96 results on '"Clark, S. M."'
Search Results
2. Juvenile xanthogranuloma with bilateral retinal detachment.
- Author
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Kwok C and Clark SM
- Subjects
- Blindness etiology, Exotropia etiology, Humans, Infant, Male, Retinal Detachment etiology, Xanthogranuloma, Juvenile complications
- Published
- 2015
- Full Text
- View/download PDF
3. Susceptibility in vitro of canine methicillin-resistant and -susceptible staphylococcal isolates to fusidic acid, chlorhexidine and miconazole: opportunities for topical therapy of canine superficial pyoderma.
- Author
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Clark SM, Loeffler A, and Bond R
- Subjects
- Administration, Topical, Animals, Anti-Bacterial Agents therapeutic use, Chlorhexidine therapeutic use, Dog Diseases drug therapy, Dogs, Drug Synergism, Fusidic Acid therapeutic use, Germany, Miconazole therapeutic use, Microbial Sensitivity Tests, Pyoderma drug therapy, Pyoderma microbiology, Staphylococcal Skin Infections drug therapy, Staphylococcus isolation & purification, United Kingdom, Anti-Bacterial Agents pharmacology, Chlorhexidine pharmacology, Dog Diseases microbiology, Fusidic Acid pharmacology, Miconazole pharmacology, Staphylococcal Skin Infections microbiology, Staphylococcus drug effects
- Abstract
Objectives: Increasing multidrug resistance amongst canine pathogenic staphylococci has renewed interest in topical antibacterial therapy for skin infections in the context of responsible veterinary prescribing. We therefore determined the activity in vitro of three clinically relevant topical agents and synergism between two of them against Staphylococcus pseudintermedius and Staphylococcus aureus., Methods: The MICs of fusidic acid (n = 199), chlorhexidine (n = 198), miconazole (n = 198) and a 1:1 combination of miconazole/chlorhexidine (n = 198) were determined for canine isolates [50 MRSA and 49 methicillin-resistant S. pseudintermedius (MRSP), 50 MSSA and 50 methicillin-susceptible S. pseudintermedius (MSSP)] collected from the UK and Germany using an agar dilution method (CLSI VET01-A4). Fractional inhibitory concentration (FIC) indices were calculated to assess the interaction of miconazole with chlorhexidine., Results: MICs of each drug/combination were significantly (P < 0.0005) higher for S. aureus when compared with S. pseudintermedius. Most strains (n = 172) had an MIC of fusidic acid of ≤0.03 mg/L (MIC ≥64 mg/L, n = 5 MRSA). All strains had MICs of chlorhexidine of 0.5-4 mg/L, except for one MRSA (MIC = 8 mg/L). All but four strains had MICs of miconazole of 1-4 mg/L (MIC = 16 mg/L, n = 3; MIC = 256 mg/L, n = 1). Miconazole/chlorhexidine (1:1 ratio) had a synergistic effect against 49/50 MRSA, 31/50 MSSA, 12/49 MRSP and 23/49 MSSP., Conclusions: Since the majority of these staphylococci, including methicillin-resistant isolates, had MICs that should be readily exceeded by topical skin application of these agents, their therapeutic efficacy for canine superficial pyoderma should be assessed. The synergistic interaction shown in vitro supports further clinical evaluation of miconazole/chlorhexidine combination therapy for staphylococcal infection., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.)
- Published
- 2015
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4. Beat note stabilization of mode-locked lasers for quantum information processing.
- Author
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Islam R, Campbell WC, Choi T, Clark SM, Conover CW, Debnath S, Edwards EE, Fields B, Hayes D, Hucul D, Inlek IV, Johnson KG, Korenblit S, Lee A, Lee KW, Manning TA, Matsukevich DN, Mizrahi J, Quraishi Q, Senko C, Smith J, and Monroe C
- Abstract
We stabilize a chosen radio frequency beat note between two optical fields derived from the same mode-locked laser pulse train in order to coherently manipulate quantum information. This scheme does not require access or active stabilization of the laser repetition rate. We implement and characterize this external lock, in the context of two-photon stimulated Raman transitions between the hyperfine ground states of trapped 171Yb(+) quantum bits.
- Published
- 2014
- Full Text
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5. Hysteretically reversible phase transition in a molecular glass.
- Author
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Kalkan B, Sonneville C, Martinet C, Champagnon B, Aitken BG, Clark SM, and Sen S
- Abstract
Pressure induced densification in a molecular arsenic sulfide glass is studied at ambient temperature using x-ray scattering, absorption and Raman spectroscopic techniques in situ in a diamond anvil cell. The relatively abrupt changes in the position of the first sharp diffraction peak, FSDP, and the pressure-volume equation of state near ∼2 GPa suggest a phase transition between low- and high-density amorphous phases characterized by different densification mechanisms and rates. Raman spectroscopic results provide clear evidence that the phase transition corresponds to a topological transformation between a low-density molecular structure and a high-density network structure via opening of the constituent As(4)S(3) cage molecules and bond switching. Pressure induced mode softening of the high density phase suggests a low dimensional nature of the network. The phase transformation is hysteretically reversible, and therefore, reminiscent of a first-order phase transition.
- Published
- 2012
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6. Coherent error suppression in multiqubit entangling gates.
- Author
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Hayes D, Clark SM, Debnath S, Hucul D, Inlek IV, Lee KW, Quraishi Q, and Monroe C
- Abstract
We demonstrate a simple pulse shaping technique designed to improve the fidelity of spin-dependent force operations commonly used to implement entangling gates in trapped ion systems. This extension of the Mølmer-Sørensen gate can theoretically suppress the effects of certain frequency and timing errors to any desired order and is demonstrated through Walsh modulation of a two qubit entangling gate on trapped atomic ions. The technique is applicable to any system of qubits coupled through collective harmonic oscillator modes.
- Published
- 2012
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7. Nature of phase transitions in crystalline and amorphous GeTe-Sb2Te3 phase change materials.
- Author
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Kalkan B, Sen S, and Clark SM
- Abstract
The thermodynamic nature of phase stabilities and transformations are investigated in crystalline and amorphous Ge(1)Sb(2)Te(4) (GST124) phase change materials as a function of pressure and temperature using high-resolution synchrotron x-ray diffraction in a diamond anvil cell. The phase transformation sequences upon compression, for cubic and hexagonal GST124 phases are found to be: cubic → amorphous → orthorhombic → bcc and hexagonal → orthorhombic → bcc. The Clapeyron slopes for melting of the hexagonal and bcc phases are negative and positive, respectively, resulting in a pressure dependent minimum in the liquidus. When taken together, the phase equilibria relations are consistent with the presence of polyamorphism in this system with the as-deposited amorphous GST phase being the low entropy low-density amorphous phase and the laser melt-quenched and high-pressure amorphized GST being the high entropy high-density amorphous phase. The metastable phase boundary between these two polyamorphic phases is expected to have a negative Clapeyron slope., (© 2011 American Institute of Physics)
- Published
- 2011
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8. Tenascin-X deficiency and Ehlers-Danlos syndrome: a case report and review of the literature.
- Author
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O'Connell M, Burrows NP, van Vlijmen-Willems MJ, Clark SM, and Schalkwijk J
- Subjects
- Adult, Child, DNA Mutational Analysis, Ehlers-Danlos Syndrome pathology, Enzyme-Linked Immunosorbent Assay, Female, Humans, Male, Middle Aged, Phenotype, Tenascin genetics, Ehlers-Danlos Syndrome genetics, Tenascin deficiency
- Abstract
Tenascin-X is a large extracellular matrix glycoprotein that is widely distributed within connective tissues and is associated with an autosomal recessive type of Ehlers-Danlos syndrome (EDS). Tenascin-X represents the first EDS susceptibility gene that does not code for a fibrillar collagen or collagen-processing enzyme. We describe a paediatric case of tenascin-X deficiency and review the literature., (© 2010 The Authors. BJD © 2010 British Association of Dermatologists.)
- Published
- 2010
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9. Silver hair in a 3-year-old.
- Author
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Batchelor RJ and Clark SM
- Subjects
- Cerebellum pathology, Child, Preschool, Diagnosis, Differential, Female, Humans, Hydrocephalus diagnosis, Hydrocephalus surgery, Piebaldism genetics, Hair Color, Meningitis diagnosis, Piebaldism diagnosis
- Published
- 2009
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10. Primary carbonatite melt from deeply subducted oceanic crust.
- Author
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Walter MJ, Bulanova GP, Armstrong LS, Keshav S, Blundy JD, Gudfinnsson G, Lord OT, Lennie AR, Clark SM, Smith CB, and Gobbo L
- Abstract
Partial melting in the Earth's mantle plays an important part in generating the geochemical and isotopic diversity observed in volcanic rocks at the surface. Identifying the composition of these primary melts in the mantle is crucial for establishing links between mantle geochemical 'reservoirs' and fundamental geodynamic processes. Mineral inclusions in natural diamonds have provided a unique window into such deep mantle processes. Here we provide experimental and geochemical evidence that silicate mineral inclusions in diamonds from Juina, Brazil, crystallized from primary and evolved carbonatite melts in the mantle transition zone and deep upper mantle. The incompatible trace element abundances calculated for a melt coexisting with a calcium-titanium-silicate perovskite inclusion indicate deep melting of carbonated oceanic crust, probably at transition-zone depths. Further to perovskite, calcic-majorite garnet inclusions record crystallization in the deep upper mantle from an evolved melt that closely resembles estimates of primitive carbonatite on the basis of volcanic rocks. Small-degree melts of subducted crust can be viewed as agents of chemical mass-transfer in the upper mantle and transition zone, leaving a chemical imprint of ocean crust that can possibly endure for billions of years.
- Published
- 2008
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11. A comparative study of the Children's Dermatology Life Quality Index (CDLQI) in paediatric dermatology clinics in the UK and Bulgaria.
- Author
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Clayton TH, Clark SM, Britton J, Pavlov S, and Radev S
- Subjects
- Adolescent, Bulgaria, Child, Child, Preschool, Female, Humans, Infant, Infant, Newborn, Male, Translations, United Kingdom, Dermatology methods, Pediatrics methods, Quality of Life, Skin Diseases psychology, Surveys and Questionnaires
- Published
- 2007
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12. Congenital plaque on the chest. Diagnosis: solitary giant congenital juvenile xanthogranuloma.
- Author
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Clayton TH, Mitra A, Holder J, and Clark SM
- Subjects
- Diagnosis, Differential, Disease Progression, Female, Humans, Infant, Thorax pathology, Xanthogranuloma, Juvenile congenital, Carcinoma in Situ pathology, Skin Neoplasms pathology, Xanthogranuloma, Juvenile pathology
- Published
- 2007
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13. A slowly enlarging painless nodule on the elbow.
- Author
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Clayton TH and Clark SM
- Subjects
- Adolescent, Calcinosis surgery, Elbow, Humans, Male, Skin Neoplasms surgery, Calcinosis pathology, Skin Neoplasms pathology
- Published
- 2007
- Full Text
- View/download PDF
14. The treatment of severe atopic dermatitis in childhood with narrowband ultraviolet B phototherapy.
- Author
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Clayton TH, Clark SM, Turner D, and Goulden V
- Subjects
- Adolescent, Child, Chronic Disease, Female, Follow-Up Studies, Humans, Male, Retrospective Studies, Dermatitis, Atopic radiotherapy, Ultraviolet Therapy
- Abstract
Background: There is a lack of data regarding the use of narrowband ultraviolet B (NB-UVB) phototherapy in children with atopic dermatitis (AD). Many centres use this mode of treatment for children with AD; however, there have only been two previous studies observing the effect of NB-UVB in children with AD., Aim: We undertook a retrospective review of children with severe eczema who had undergone NB-UVB consecutively in our department between 1999 and 2005., Methods: All children with AD who had undergone NB-UVB consecutively in our department between 1999 and 2005 were identified from the phototherapy database. Their clinical notes were reviewed for information on age, sex, skin type, minimal erythema dose (MED), adjuvant therapy, previous therapy, adverse effects, number of exposures, cumulative dose, response to treatment and length of remission., Results: In total, 50 children (83%) completed more than 10 exposures of NB-UVB. Complete clearance or minimal residual activity was achieved in 20 children (40%). A good improvement was achieved in a further 10 children (23%), and a moderate improvement in 13 (26%). Children with MEDs > 390 mJ/cm2 were more likely to clear, and this was found to be statistically significant (P = 0.02). Overall, the treatment was well tolerated and the median length of remission was 3 months., Conclusion: NB-UVB is an effective treatment for children with severe AD. Children with MEDs > 390 mJ/cm2 are more likely to clear. Further studies are needed to evaluate the efficacy of NB-UVB and long-term safety in treating children with severe AD.
- Published
- 2007
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15. Temporal changes in sebum excretion and propionibacterial colonization in preadolescent children with and without acne.
- Author
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Mourelatos K, Eady EA, Cunliffe WJ, Clark SM, and Cove JH
- Subjects
- Acne Vulgaris metabolism, Age Factors, Child, Child, Preschool, Female, Follow-Up Studies, Gram-Positive Bacterial Infections metabolism, Humans, Longitudinal Studies, Male, Sebaceous Glands microbiology, Acne Vulgaris microbiology, Gram-Positive Bacterial Infections complications, Propionibacterium acnes physiology, Sebaceous Glands metabolism, Sebum metabolism
- Abstract
Background: It is generally accepted that the onset of sebum secretion occurs before puberty in boys and girls as a result of increasing androgen output during the adrenarche. Propionibacteria are part of the commensal skin flora and, in adults, are found in highest numbers in sebum-rich areas of skin such as the face and upper trunk. Previous studies investigating the association between sebum output and propionibacterial population densities have been cross-sectional and have been carried out mainly in adults., Objectives: The purpose of this study was to examine the association between the onset of sebum secretion and expansion of the propionibacterial flora in a population of early adolescent children aged between 5.5 and 12 years, and to evaluate the temporal relation between the two factors longitudinally. In addition, the study aimed to evaluate the change with age in sebaceous gland activity and propionibacterial colonization on the skin and in the nares between children who developed acne and those who did not., Methods: Biannual examinations of volunteers included age, pubertal (Tanner) stage, weight and height, lesion counting on the face, propionibacterial colonization on the skin surface and in the nares and sebum secretion. A longitudinal analysis based on all observations of each subject throughout the study was applied to examine the change of sebaceous gland activity and propionibacterial colonization with age and pubertal stage. A generalized estimating equation was used with a 0.05 level of significance., Results: The commencement of sebum production was asynchronous, with only a small number of follicles initially starting to secrete sebum onto the skin surface. The number of secreting follicles and the area of sebum increased with age and pubertal stage (P < 0.0001, P < 0.05, respectively). Numbers of propionibacteria on the skin tended to increase after the age of 9 years, but not significantly so. In contrast, numbers of propionibacteria in the nares increased significantly with age (P < 0.0001) but not with pubertal maturation. Children who developed acne had higher sebum output and propionibacterial densities with increasing age than children who did not develop acne. This effect was significant for the increase of total sebum area with age in pubertal children (P = 0.0023), the increase in number of secreting follicles with age (P = 0.020) in prepubertal children, and the increase in propionibacteria densities in the nares with age (P = 0.0005) in pubertal children. Sebaceous gland activity and propionibacterial numbers on the skin surface remained unchanged with increasing age in children who did not develop acne. Propionibacterial population densities in the nares increased with age regardless of the development of acne., Conclusions: Onset of sebum secretion and consequently expansion of the propionibacterial skin flora occur earlier in children who develop acne than in children of the same age and pubertal status who do not develop acne. These observations suggest that postponing the onset of sebum production or the expansion of the propionibacterial skin flora until after puberty may represent ways of preventing the disease or minimizing its severity. Determinants of propionibacterial colonization on the skin and in the nares may be different.
- Published
- 2007
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16. Unilateral naevoid trichoepitheliomas on the face of a child.
- Author
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Strauss RM, Merchant WJ, Stainforth JM, and Clark SM
- Subjects
- Child, Female, Humans, Facial Neoplasms pathology, Neoplasms, Basal Cell pathology, Skin Neoplasms pathology
- Abstract
Trichoepitheliomas are benign epidermal appendage tumours that present most commonly as solitary lesions, and less often as multiple, symmetrically distributed lesions on the face, scalp, neck and trunk. Only a few patients have been reported in whom trichoepitheliomas were found as unusually configured linear or plaque-like confluent lesions, all of which occurred in patients with skin types V or VI. We describe a white girl with a hemifacial plaque of confluent naevoid trichoepitheliomas, the first report of such lesions in a white patient.
- Published
- 2006
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17. Killed Mycobacterium vaccae suspension in children with moderate-to-severe atopic dermatitis: a randomized, double-blind, placebo-controlled trial.
- Author
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Berth-Jones J, Arkwright PD, Marasovic D, Savani N, Aldridge CR, Leech SN, Morgan C, Clark SM, Ogilvie S, Chopra S, Harper JI, Smith CH, Rook GA, and Friedmann PS
- Subjects
- Adolescent, Bacterial Vaccines administration & dosage, Bacterial Vaccines adverse effects, Child, Child, Preschool, Dermatitis, Atopic therapy, Double-Blind Method, Drug Administration Schedule, Eczema drug therapy, Eczema immunology, Female, Humans, Injections, Intradermal adverse effects, Male, Severity of Illness Index, Treatment Outcome, Bacterial Vaccines immunology, Dermatitis, Atopic immunology, Mycobacterium immunology
- Abstract
Background: The hygiene hypothesis is often proposed to explain the high prevalence of atopy in the western world. Dysregulation of the immune system may result from inadequate exposure to micro-organisms such as mycobacteria. A small trial suggested that a killed extract of Mycobacterium vaccae ameliorates atopic dermatitis (AD)., Objectives: To confirm in a large clinical trial whether killed M. vaccae ameliorates AD in 5-16-year-old children., Methods: This was a randomized, placebo-controlled, double-blind, multi-centre study of the effect of intradermal injection of killed M. vaccae (0.1 or 1 mg) on patients, aged 5-16, with moderate-to-severe AD. Patients were followed up for 24 weeks. The primary end point was the change in severity of AD at 12 weeks, assessed using the six area, six-sign, atopic dermatitis (SASSAD) score. Secondary end points included changes in disease extent, patient's global assessment and children's dermatology life quality index., Results: There were 166 patients randomized. The mean SASSAD score fell to a similar degree at week 12 in all treatment arms: from 33 to 24, (26%) in the high-dose group, from 30 to 23 (25%) in the low-dose group and from 36 to 27 (24%) in the placebo group (P>0.05). Secondary end points followed the same trend. Adverse events were generally those expected to occur in this population. Injection site reactions occurred in 32 patients at week 4., Conclusions: M. vaccae was no more effective than the placebo in ameliorating the severity of AD.
- Published
- 2006
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18. Allergic contact dermatitis in children: should pattern of dermatitis determine referral? A retrospective study of 500 children tested between 1995 and 2004 in one U.K. centre.
- Author
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Clayton TH, Wilkinson SM, Rawcliffe C, Pollock B, and Clark SM
- Subjects
- Adolescent, Age Factors, Allergens adverse effects, Child, Child, Preschool, Dermatitis, Allergic Contact etiology, Dermatitis, Allergic Contact pathology, Female, Humans, Infant, Infant, Newborn, Male, Nickel adverse effects, Patch Tests, Referral and Consultation, Retrospective Studies, Sex Factors, Statistics as Topic, Dermatitis, Allergic Contact diagnosis
- Abstract
Background: Allergic contact dermatitis (ACD) increases with age, and a prevalence of between 13.3% and 24.5% has been reported. Patch testing infants may be particularly difficult, and false-positive reactions may occur., Objectives: The purpose of this retrospective study was to determine whether the site of primary dermatitis in children could predict a diagnosis of ACD. The current frequency of sensitization in children was also evaluated and the main sensitizing substances among children were verified., Methods: Between 1995 and 2004, 500 children were patch tested and entered on to the patch test database at Leeds General Infirmary. Analysis of the database included identifying the presenting patterns of eczema and reviewing the patch test results for each child., Results: Of the children, 133 (27%) had one or more positive patch test result. The effect of age on the likelihood of a positive patch test was highly significant (P < 0.001). Girls were significantly more likely to have a positive patch test compared with boys: odds ratio for a positive test 0.62 (95% confidence interval 0.41-0.95; P = 0.029). Type IV allergy to nickel (33%) was the most frequent finding. Reactions to fragrance mix (18%), cobalt (11%), mercapto chemicals, Myroxylon pereirae and p-phenylenediamine (each 8%) were the next most common. No statistical significance was found in the relationship between the site of primary dermatosis and a positive patch test result., Conclusions: The pattern of presenting dermatitis in children should not determine referral for patch testing. Any child with persistent eczema should be referred for patch testing.
- Published
- 2006
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19. Treatment of recalcitrant hidradenitis suppurativa with oral ciclosporin.
- Author
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Rose RF, Goodfield MJ, and Clark SM
- Subjects
- Administration, Oral, Adult, Female, Humans, Male, Treatment Outcome, Cyclosporine administration & dosage, Dermatologic Agents administration & dosage, Hidradenitis Suppurativa drug therapy
- Published
- 2006
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20. Iron spin transition in Earth's mantle.
- Author
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Speziale S, Milner A, Lee VE, Clark SM, Pasternak MP, and Jeanloz R
- Abstract
High-pressure Mössbauer spectroscopy on several compositions across the (Mg,Fe)O magnesiowüstite solid solution confirms that ferrous iron (Fe(2+)) undergoes a high-spin to low-spin transition at pressures and for compositions relevant to the bulk of the Earth's mantle. High-resolution x-ray diffraction measurements document a volume change of 4-5% across the pressure-induced spin transition, which is thus expected to cause seismological anomalies in the lower mantle. The spin transition can lead to dissociation of Fe-bearing phases such as magnesiowüstite, and it reveals an unexpected richness in mineral properties and phase equilibria for the Earth's deep interior.
- Published
- 2005
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21. A new paradigm to extend diffraction measurements beyond the megabar regime.
- Author
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Clark SM and Jeanloz R
- Abstract
The possibility of using X-ray diffraction to precisely monitor crystal structure at the extremes of pressure and temperature produced by shock-wave loading is explored. A summary of the advantages of using various X-ray sources for this work and an outline of the necessary experimental layout is given.
- Published
- 2005
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22. Rectal bleeding following acitretin therapy for discoid lupus erythematosus.
- Author
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Fairhurst DA and Clark SM
- Subjects
- Conjunctivitis chemically induced, Epistaxis chemically induced, Facial Dermatoses drug therapy, Female, Humans, Middle Aged, Rectum, Scalp Dermatoses drug therapy, Acitretin adverse effects, Gastrointestinal Hemorrhage chemically induced, Keratolytic Agents adverse effects, Lupus Erythematosus, Discoid drug therapy
- Published
- 2005
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23. A case of childhood dermatofibrosarcoma protuberans without detected cytogenetic abnormality.
- Author
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Strauss RM, Merchant WJ, Roberts P, Wright AL, and Clark SM
- Subjects
- Biopsy, Child, Preschool, Cytogenetic Analysis, Dermatofibrosarcoma genetics, Diagnosis, Differential, Humans, Male, Predictive Value of Tests, Skin Neoplasms genetics, Dermatofibrosarcoma pathology, Skin Neoplasms pathology
- Abstract
Dermatofibrosarcoma protuberans (DFSP) is a rare, infiltrative skin tumour of intermediate malignancy, with a limited potential for metastasis but a high rate of recurrence; specific cytogenetic abnormalities are now known. Childhood DFSP has been considered a rarity in the past, but it is now recognized that many cases of childhood DFSP are diagnosed only in adulthood. Despite advances in the understanding of its pathogenesis as well as the development of valuable immunohistochemical and cytogenetic diagnostic techniques, there often remains a significant delay between the initial presentation and diagnosis of DFSP. We report a case of childhood DFSP in which the diagnosis was reached only after a nodular lesion developed in a plaque that was initially present. Causes for delay between initial presentation and diagnosis in childhood DFSP are discussed. Histology and immunostaining in our patient showed the typical features of DFSP, but the G-banded cytogenetic analysis of short-term tissue culture was negative. However, this technique offers only a detection rate between 50% and 80%. Clinicians should be aware of the limitations of newer diagnostic techniques. Increasing recognition amongst paediatricians and paediatric dermatologists that childhood DFSP is not as rare as once believed will probably lead to the use of newer diagnostic methods at an earlier stage, and so reduce the delay between the onset of symptoms and diagnosis.
- Published
- 2003
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24. A SAXS/WAXS XAFS study of crystallisation in cordierite glass.
- Author
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Greaves GN, Bras W, Oversluizen M, and Clark SM
- Abstract
New Cr X-ray absorption fine structure (XAFS) data have been combined with the results of small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) experiments to probe in detail the crystallisation mechanism in cordierite (Mg2Al4Si5O18) glass doped with 0.34 mol% Cr2O3. By direct comparison with chromo-aluminate spinels (MgCr2xAl2(1 - x)O4) Cr XAFS is used to determine the composition of the devitrified Cr species. This is identified as MgCr(0.18)Al(1.82)O4, which can be directly related to the Cr content in the starting glass and as a result the total crystalline volume in the fully developed ceramic is predicted to be 4%. In situ WAXS not only reveals the presence of the spinel phase but also a silica-rich stuffed quartz phase. This grows independently of the spinel and is probably nucleated from the glass surface. From our knowledge of the compositions of both crystalline phases we are able to deduce that the SAXS contrast between the surrounding glass and the spinel crystallites is 30 times greater than that between the quartz crystallites and the glass matrix, and therefore dominates the measured scattered intensity and the SAXS invariant that is derived from it. As a consequence we are able to show that the spinel crystalline volume fraction inherent in the SAXS is in close agreement with the 4% value obtained from the Cr XAFS. Furthermore in situ SAXS reveals the gradual development of the spinel particle size and shape during heat treatment. This is conducted in the super-cooled region just above the glass transition temperature, Tg. By employing a two-step annealing process nucleation can be separated from growth and from time-resolved SAXS measurements the alumino-chromate nanocrystals are found to be closely monodispersed. Over a total time course of 600 min they grow from rough crystallites to smooth spherical particles of radius 21 +/- 2 nm, with a final density of (1.2 +/- 0.4) x 10(21) m(-3). As the process of ceramic formation takes place in the viscous melt, growth is indeed found to be limited by diffusion and is complete when all the Cr is exhausted. We use this comprehensive in situ study of crystallisation in cordierite glass to demonstrate the advantages of combining SAXS, WAXS and XAFS for probing the time-resolved chemistry, the microstructure and its development from nucleation sites, that underpins the processing of nanoparticle ceramics.
- Published
- 2003
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25. Comedogenesis: some aetiological, clinical and therapeutic strategies.
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Cunliffe WJ, Holland DB, Clark SM, and Stables GI
- Subjects
- Administration, Cutaneous, Humans, In Situ Hybridization, Keratins metabolism, Retinoids therapeutic use, Acne Vulgaris classification, Acne Vulgaris etiology, Acne Vulgaris therapy, Keratinocytes metabolism
- Abstract
Hypercornification is an early feature of acne and usually precedes inflammation. It is associated with ductal hyperproliferation, and there are many controlling factors such as androgens, retinoids, sebum composition and cytokines. Cycling of normal follicles and of comedones may explain the natural resolution of comedones and, in the longer term, resolution of the disease itself. There is a need to tailor treatment according to comedonal type. Suboptimal therapy can often result from inappropriate assessments of comedones, especially microcomedones, sandpaper comedones, submarine comedones and macrocomedones. Macrocomedones can produce devastating acne flares, particularly if patients are inappropriately prescribed oral isotretinoin. Gentle cautery under topical local anaesthesia is a useful therapy in the treatment of such lesions. The newer retinoids and new formulations of all-trans-retinoic acid show a better benefit/risk ratio., (Copyright 2003 S. Karger AG, Basel)
- Published
- 2003
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26. Laser treatment of erythema and telangiectasia associated with rosacea.
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Clark SM, Lanigan SW, and Marks R
- Subjects
- Adult, Erythema etiology, Erythema pathology, Female, Flushing etiology, Humans, Lasers adverse effects, Male, Middle Aged, Telangiectasis etiology, Telangiectasis pathology, Erythema radiotherapy, Laser Therapy, Rosacea complications, Telangiectasis radiotherapy
- Abstract
The response of rosacea-associated erythema and telangiectasia to treatment with the pulsed tunable dye laser (PDL) was evaluated in 12 patients. Improvements in erythema, telangiectasia, flushing, the physician's and the patient's perception of overall severity, treatment tolerability, and the adverse side effects were examined. With the sole exception of the patient's assessment of overall severity we have found highly significant improvements in all other parameters evaluated, with excellent tolerance of treatment. We therefore conclude that the PDL is a safe and effective treatment for the erythemato-telangiectatic component of rosacea.
- Published
- 2002
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27. Staphylococcus aureus colonization of children with atopic eczema and their parents.
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Patel GK, Wyatt H, Kubiak EM, Clark SM, and Mills CM
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- Adolescent, Adult, Carrier State, Child, Preschool, Humans, Infant, Prevalence, United Kingdom epidemiology, Dermatitis, Atopic microbiology, Staphylococcal Infections epidemiology, Staphylococcal Infections microbiology, Staphylococcus aureus isolation & purification
- Published
- 2001
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28. Exercise in the reduction of cardiovascular events. Lessons from epidemiologic trials.
- Author
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Gibbons LW and Clark SM
- Subjects
- Cardiovascular Diseases mortality, Clinical Trials as Topic, Coronary Disease mortality, Humans, Myocardial Infarction mortality, Risk Factors, Survival Rate, Cardiovascular Diseases prevention & control, Coronary Disease prevention & control, Exercise, Myocardial Infarction prevention & control
- Abstract
In conclusion, much has been learned about the effects of exercise in reducing events in those with CHD. Some data are confusing, however, and some gaping holes exist in our understanding. Hopefully, new data forthcoming in the next 5 to 10 years will clear up this picture significantly. Meanwhile, cardiovascular exercise, coupled with other risk factor reduction, has been firmly established as a lifesaving and life-improving tool in those who have developed manifestations of CHD.
- Published
- 2001
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29. Early use of percutaneous endoscopic gastrostomy feeding in toxic epidermal necrolysis.
- Author
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Clark SM, Thomas G, and Holt PJ
- Subjects
- Humans, Male, Middle Aged, Enteral Nutrition methods, Gastrostomy methods, Stevens-Johnson Syndrome therapy
- Published
- 2001
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- View/download PDF
30. Acute necrotic skin reaction to intramuscular Depo-Provera.
- Author
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Clark SM and Lanigan SW
- Subjects
- Adult, Female, Humans, Injections, Intramuscular, Necrosis, Skin drug effects, Contraceptive Agents, Female adverse effects, Medroxyprogesterone Acetate adverse effects, Skin pathology
- Published
- 2000
- Full Text
- View/download PDF
31. Treatment of keratosis pilaris atrophicans with the pulsed tunable dye laser.
- Author
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Clark SM, Mills CM, and Lanigan SW
- Subjects
- Adolescent, Adult, Child, Child, Preschool, Erythema etiology, Face, Female, Humans, Male, Statistics, Nonparametric, Treatment Outcome, Keratosis therapy, Laser Therapy
- Abstract
Background: Few therapies are currently available to treat keratosis pilaris atrophicans (KPA), a spectrum of disorders which includes ulerythema ophryogenes and atrophoderma vermiculata., Objective: To evaluate the response of KPA to treatment with the pulsed dye laser (PDL) with regard to improvements in erythema and skin roughness, treatment tolerability, and side effects., Methods: Treatment of all facial areas involved with KPA with the PDL at 585 nm was evaluated in 12 patients. Prior to and after each treatment skin erythema was estimated using an erythema meter, and skin roughness was analysed using micrometer evaluation of a skin surface biopsy taken from the same mapped area and analysed by computer to calculate the roughness profile., Results: Patients received 2 to 8 treatments with the PDL with energies ranging from 6.0 to 7.5 J/cm2. Clinical improvement was noted in all patients with significant reduction in erythema scores. Pre-treatment scores ranged from 4 to 13 (mean 8.3) and post-treatment 0 to 8 (mean 3.1) (P < 0.05). Improvements in skin roughness were clinically apparent in all but two patients, but these were not significant on evaluation of skin surface biopsies. Treatment was generally well tolerated, and side effects other than local pain during treatment were very few., Conclusion: PDL treatment appears to be a safe and effective treatment for the erythema associated with KPA but does not give significant improvement in associated skin roughness.
- Published
- 2000
- Full Text
- View/download PDF
32. In situ EXAFS, X-ray diffraction and photoluminescence for high-pressure studies.
- Author
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Sapelkin AV, Bayliss SC, Russell D, Clark SM, and Dent AJ
- Abstract
A new facility for simultaneous extended X-ray absorption of fine structure (EXAFS), X-ray diffraction and photoluminescence measurements under high pressures has been developed for use on station 9.3 at the Daresbury Laboratory Synchrotron Radiation Source. This high-pressure facility can be used at any suitable beamline at a synchrotron source. Full remote operation of the rig allows simultaneous collection of optical and structural data while varying the pressure. The set-up is very flexible and can be tailored for a particular experiment, such as time- or temperature-dependent measurements. A new approach to the collection of high-pressure EXAFS data is also presented. The approach significantly shortens the experimental times and allows a dramatic increase in the quality of EXAFS data collected. It also opens up the possibility for EXAFS data collection at any pressure which can be generated using a diamond cell. The high quality of data collected is demonstrated with a GaN case study. Particular attention will be paid to the use of energy-dispersive EXAFS and quick-scanning EXAFS techniques under pressure.
- Published
- 2000
- Full Text
- View/download PDF
33. Site-directed cross-linking of b to the alpha, beta, and a subunits of the Escherichia coli ATP synthase.
- Author
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McLachlin DT, Coveny AM, Clark SM, and Dunn SD
- Subjects
- Amino Acid Substitution, Binding Sites, Cell Membrane enzymology, Cross-Linking Reagents, Cysteine, Escherichia coli genetics, Macromolecular Substances, Models, Molecular, Mutagenesis, Site-Directed, Peptide Fragments chemistry, Proton-Translocating ATPases genetics, Recombinant Proteins chemistry, Recombinant Proteins metabolism, Sequence Deletion, Escherichia coli enzymology, Proton-Translocating ATPases chemistry, Proton-Translocating ATPases metabolism
- Abstract
The b subunit dimer of the Escherichia coli ATP synthase, along with the delta subunit, is thought to act as a stator to hold the alpha(3)beta(3) hexamer stationary relative to the a subunit as the gammaepsilonc(9-12) complex rotates. Despite their essential nature, the contacts between b and the alpha, beta, and a subunits remain largely undefined. We have introduced cysteine residues individually at various positions within the wild type membrane-bound b subunit, or within b(24-156), a truncated, soluble version consisting only of the hydrophilic C-terminal domain. The introduced cysteine residues were modified with a photoactivatable cross-linking agent, and cross-linking to subunits of the F(1) sector or to complete F(1)F(0) was attempted. Cross-linking in both the full-length and truncated forms of b was obtained at positions 92 (to alpha and beta), and 109 and 110 (to alpha only). Mass spectrometric analysis of peptide fragments derived from the b(24-156)A92C cross-link revealed that cross-linking took place within the region of alpha between Ile-464 and Met-483. This result indicates that the b dimer interacts with the alpha subunit near a non-catalytic alpha/beta interface. A cysteine residue introduced in place of the highly conserved arginine at position 36 of the b subunit could be cross-linked to the a subunit of F(0) in membrane-bound ATP synthase, implying that at least 10 residues of the polar domain of b are adjacent to residues of a. Sites of cross-linking between b(24-156)A92C and beta as well as b(24-156)I109C and alpha are proposed based on the mass spectrometric data, and these sites are discussed in terms of the structure of b and its interactions with the rest of the complex.
- Published
- 2000
- Full Text
- View/download PDF
34. Comedogenesis: some new aetiological, clinical and therapeutic strategies.
- Author
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Cunliffe WJ, Holland DB, Clark SM, and Stables GI
- Subjects
- Acne Vulgaris pathology, Acne Vulgaris therapy, Cautery, Humans, Retinoids therapeutic use, Acne Vulgaris etiology
- Abstract
Hypercornification is an early feature of acne and precedes inflammation. It is associated with ductal hyperproliferation and there are many controlling factors such as androgens, retinoids and cytokines. Cycling of normal follicles and of comedones may explain the natural resolution of comedones and, in the longer term, resolution of the disease itself. There is a need to tailor treatment according to comedonal type. Suboptimal therapy can often result from inappropriate assessments of comedones, especially microcomedones, missed comedones, sandpaper comedones, submarine comedones and macrocomedones. Macrocomedones can produce devastating acne flares, particularly if patients are inappropriately prescribed oral isotretinoin. Gentle cautery under topical local anaesthesia is a useful therapy in the treatment of such lesions. The newer retinoids and new formulations of all-trans-retinoic acid show a better benefit/risk ratio. Evidence-based studies are required to allow adequate comparisons.
- Published
- 2000
- Full Text
- View/download PDF
35. Rapid methods for the calibration of solid-state detectors.
- Author
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Walker D, Clark SM, Jones RL, and Cranswick LM
- Abstract
A complementary pair of rapid methods for the energy calibration of solid-state detectors have been developed. Each method requires only a single measurement from either (i) a glass sample containing elements chosen to produce fluorescence lines over a suitable energy range when exposed to a polychromatic beam of X-rays, or (ii) a powder diffraction standard in the presence of diffraction slits. The fluorescent glass method has the advantage of allowing simultaneous energy calibration of a number of detectors without requiring diffraction slits. There is the potential for the glass material to be incorporated into virtually any sample holder to allow a continuous in situ calibration. Complementary observations of a powder diffraction standard allow simultaneous calibration of diffraction 2theta and monitoring of the detector for drift.
- Published
- 2000
- Full Text
- View/download PDF
36. Men's attitudes regarding genetic testing for hereditary prostate cancer risk.
- Author
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Miesfeldt S, Jones SM, Cohn W, Lippert M, Haden K, Turner BL, Martin-Fries T, and Clark SM
- Subjects
- Adult, Aged, Aged, 80 and over, Humans, Male, Middle Aged, Risk Factors, Genetic Testing psychology, Health Knowledge, Attitudes, Practice, Prostatic Neoplasms genetics
- Abstract
Objectives: Little is known about the attitudes of men unselected for a family history for prostate cancer concerning genetic testing for prostate cancer risk or genetic testing for inherited cancer predisposition. To explore this, we examined the interest in molecular testing for hereditary prostate cancer (HPC) predisposition among a self-selected cohort of 342 men presenting for prostate cancer screening., Methods: Participants were surveyed concerning their attitudes about DNA testing for HPC predisposition and knowledge of prostate cancer-associated risk factors, including heredity., Results: Of the participants completing the survey, 92% expressed interest in learning about DNA testing, and 89% stated that they would undergo DNA analysis for HPC predisposition, if available. Twenty-eight percent of respondents failed to demonstrate an adequate understanding of the concept of "inherited tendency." The demonstrated level of understanding of this concept did not differ by the respondent's family history, although it varied by race. An interest in learning about or undergoing testing did not vary by race, family history, or demonstrated understanding of the concept of inherited risk., Conclusions: Among men presenting for routine prostate cancer screening, interest in learning about testing for HPC predisposition and in having such testing performed may be high. The data also provide evidence that, in a population of men unselected for family history, interest in molecular testing for this common, male-specific cancer may parallel the high interest level demonstrated among women in DNA testing for inherited breast and ovarian cancer risk.
- Published
- 2000
- Full Text
- View/download PDF
37. Localised facial swelling associated with isotretinoin.
- Author
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Patel GK, Chowdhury MM, Clark SM, and Knight AG
- Subjects
- Acne Vulgaris drug therapy, Adult, Humans, Male, Middle Aged, Edema chemically induced, Face, Isotretinoin adverse effects
- Published
- 1999
- Full Text
- View/download PDF
38. Conflicting responses: the experiences of fathers of infants diagnosed with severe congenital heart disease.
- Author
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Clark SM and Miles MS
- Subjects
- Adaptation, Psychological, Adult, Emotions, Heart Defects, Congenital nursing, Humans, Infant, Newborn, Internal-External Control, Longitudinal Studies, Male, Object Attachment, Professional-Family Relations, Fathers psychology, Heart Defects, Congenital psychology
- Abstract
Purpose: To explore the experiences of fathers of infants newly diagnosed with severe congenital heart disease., Design: An analysis of qualitative data collected as part of a larger longitudinal study of parenting the medically fragile infant., Participants: Eight fathers whose infants were hospitalized for severe congenital heart disease, were technology dependent at time of enrollment, and were expected to have serious chronic health problems at discharge. DATA COLLECTION MEASURES: Semistructured interviews in the hospital and the home until the child reached 15 months adjusted age., Results: Findings indicate that fathers experience four interrelated conflicting reactions: the joy of seeing the child born and becoming a father, plus the sadness and loss associated with the baby's illness; the challenge of becoming attached while dealing with fears about the infant's vulnerability and potential death; the need to try to maintain control while feeling a loss of control; and the struggle to remain strong for others while hiding their intense emotions. These findings extend the previous limited research about fathers by identifying the unique conflicts fathers of seriously ill infants experience in coping with the child's diagnosis and treatment. Findings have implications for intervening with fathers during the early diagnostic phase of a serious illness, particularly serious congenital heart disease.
- Published
- 1999
- Full Text
- View/download PDF
39. An outbreak of El Tor cholera associated with a tribal funeral in Irian Jaya, Indonesia.
- Author
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Korthuis PT, Jones TR, Lesmana M, Clark SM, Okoseray M, Ingkokusumo G, and Wignall FS
- Subjects
- Cholera etiology, Cholera microbiology, Cholera mortality, Endemic Diseases, Epidemiologic Methods, Ethnicity, Female, Humans, Indonesia epidemiology, Risk Factors, Seasons, Serotyping, Surveys and Questionnaires, Vibrio cholerae classification, Cholera epidemiology, Disease Outbreaks, Funeral Rites, Vibrio cholerae isolation & purification
- Abstract
An outbreak of El Tor biotype cholera occurring in a rural village in Irian Jaya, Indonesia was evaluated for risk factors associated with death from cholera. Among those dying in the village during the epidemic, a significant association between membership in one of the five tribal groups in the village complex was associated with an elevated risk of suffering a cholera death (odds ratio = 5.9). Interviews with members of the decedents' families revealed a very strong association (odds ratio = 11.6) between risk of cholera death and having attended the two day funeral of a woman who died of a cholera-like illness a few days prior to an outbreak of cholera-like diarrheal disease in the village complex. Recent flooding may have contributed to the creation of an environment conducive to cholera transmission.
- Published
- 1998
40. Phototoxic contact dermatitis from 5-methoxypsoralen in aromatherapy oil.
- Author
-
Clark SM and Wilkinson SM
- Subjects
- 5-Methoxypsoralen, Baths, Child, Female, Humans, Methoxsalen administration & dosage, Methoxsalen adverse effects, Aromatherapy, Dermatitis, Phototoxic etiology, Methoxsalen analogs & derivatives
- Published
- 1998
- Full Text
- View/download PDF
41. Localization of a constitutively active, phagocyte-like NADPH oxidase in rabbit aortic adventitia: enhancement by angiotensin II.
- Author
-
Pagano PJ, Clark JK, Cifuentes-Pagano ME, Clark SM, Callis GM, and Quinn MT
- Subjects
- Animals, Aorta cytology, Cells, Cultured, Immunohistochemistry, NADPH Dehydrogenase metabolism, Phosphoproteins metabolism, Rabbits, Angiotensin II pharmacology, Aorta metabolism, Membrane Transport Proteins, NADPH Oxidases metabolism, Phagocytes metabolism, Vasoconstrictor Agents pharmacology
- Abstract
Superoxide anion (O2-) plays a key role in the endogenous suppression of endothelium-derived nitric oxide (NO) bioactivity and has been implicated in the development of hypertension. In previous studies, we found that O2- is produced predominantly in the adventitia of isolated rabbit aorta and acts as a barrier to NO. In the present studies, we characterize the enzyme responsible for O2- production in the adventitia and show that this enzyme is a constitutively active NADPH oxidase with similar composition as the phagocyte NADPH oxidase. Constitutive O2--generating activity was localized to aortic adventitial fibroblasts and was enhanced by the potent vasoconstrictor angiotensin II. Immunohistochemistry of aortic sections demonstrated the presence of p22(phox), gp91(phox), p47(phox), and p67(phox) localized exclusively in rabbit aortic adventitia, coincident with the site of staining for O2- production. Furthermore, immunodepletion of p67(phox) from adventitial fibroblast particulates resulted in the loss of NADPH oxidase activity, which could be restored by the addition of recombinant p67(phox). Further study into the regulation of this adventitial source of O2- is important in elucidating the mechanisms regulating the bioactivity of NO and may contribute to our understanding of the pathogenesis of hypertension.
- Published
- 1997
- Full Text
- View/download PDF
42. Improved stability and electrophoretic properties of preformed fluorescent cationic dye-DNA complexes in a taps-tetrapentylammonium buffer in agarose slab gels.
- Author
-
Zeng Z, Clark SM, Mathies RA, and Glazer AN
- Subjects
- Buffers, DNA metabolism, Fluorescent Dyes metabolism, Quaternary Ammonium Compounds chemistry, Sulfonic Acids chemistry, DNA chemistry, Electrophoresis, Agar Gel methods, Fluorescent Dyes chemistry
- Abstract
High-resolution capillary electrophoresis sizing of preformed complexes of bis-intercalating fluorescent dyes with double-stranded DNA has been demonstrated using hydroxyethylcellulose and 3-[tris-(hydroxymethyl) methylamino]-1-propanesulfonic acid-tetrapentylammonium (Taps-NPe+4) buffers (S. M. Clark and R. A. Mathies, Anal. Chem. 69, 1355-1363, 1997). Such capillary electrophoresis separations were unattainable in conventional buffers containing other cations such as Tris+, Na+, and NH+4. We report here the behavior of preformed double-stranded DNA-dye complexes on agarose slab gel electrophoresis in 40 mM Taps-NPe+4, 1 mM H2EDTA, pH 8.2. Upon electrophoresis in this buffer (a) complexes formed at DNA base pairs:dye ratios ranging from 100:1 to 5:1 show the same mobility; (b) the half-lives of DNA-dye complexes with monointercalators are two- to threefold longer than those in commonly used Tris buffers; (c) there is little dye transfer between labeled and unlabeled DNA molecules; and (d) precise two-color sizing of preformed restriction fragment-dye complexes with fluorescent bisintercalators is achieved.
- Published
- 1997
- Full Text
- View/download PDF
43. Treatment of acne with intermittent isotretinoin.
- Author
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Goulden V, Clark SM, McGeown C, and Cunliffe WJ
- Subjects
- Adult, Drug Administration Schedule, Female, Humans, Isotretinoin therapeutic use, Keratolytic Agents therapeutic use, Male, Acne Vulgaris drug therapy, Isotretinoin administration & dosage, Keratolytic Agents administration & dosage
- Abstract
Adults with acne represent an increasingly important population of acne sufferers referred for treatment. Acne, in these patients, is generally mild or moderate in severity but tends to be resistant to conventional antibiotic therapy. A study was carried out to assess the efficacy of intermittent moderate dose isotretinoin as a treatment for acne. Eighty consecutive patients, over the age of 25 years, referred with acne unresponsive to, or relapsing rapidly after three or more courses of conventional antibiotic therapy were recruited. Acne severity was assessed on the face, chest and back using the Leeds grading scale and the number of inflamed lesions was counted at the site showing the highest acne grade. The patients were 22 men and 58 women. The treatment regimen consisted of isotretinoin, 0.5 mg/kg per day for 1 week in every 4 week for a total period of 6 months. Seventy-five patients completed the study. The therapy was very well tolerated with mild cheilitis as the only side-effect. At the end of treatment, both total acne grade and lesion counts were significantly reduced (P < 0.0001). The acne had resolved in 68 (88%) patients. Twelve months after treatment, acne grades and inflamed lesion counts remained significantly improved (P < 0.0001) in the 68 patients who responded; however, 26 (39%) patients had relapsed. There was a significantly higher incidence of relapse in patients with predominantly truncal acne (P = 0.01). Patients who relapsed also had a significantly higher total acne grade, lesion count (P < 0.0001) and sebum excretion rate (P < 0.001) compared with those whose acne resolved. This study suggests that intermittent moderate dose isotretinoin may be a cost-effective alternative to full dose isotretinoin in a carefully selected group of adult patients with-acne. Selection criteria should include predominantly facial acne, total acne grade less than 1, inflamed lesion count less than 20 and sebum excretion rate less than 1.25 micrograms/cm2 per min.
- Published
- 1997
44. Multiplex dsDNA Fragment Sizing Using Dimeric Intercalation Dyes and Capillary Array Electrophoresis: Ionic Effects on the Stability and Electrophoretic Mobility of DNA-Dye Complexes.
- Author
-
Clark SM and Mathies RA
- Abstract
Methods have been developed for performing accurate, high-resolution, multiplex capillary electrophoresis separations of dsDNA using dimeric intercalation dyes as noncovalent labeling reagents. The quality of these separations is highly dependent on the cation present during electrophoresis. Using buffers that contain only one cation, we show that the tetrapentylammonium (NPe(4)(+)) ion results in high-resolution, high-sensitivity separations but that smaller ions such as sodium or the commonly used buffer ion tris produce low-resolution, low-intensity separations of DNA-dye complexes. Using an 80 mM taps-NPe(4), 1 mM H(2)EDTA, pH 8.4, 0.8% HEC separation buffer, high-quality multiplex separations were performed using TOTO and buTOTIN, YOYO and TOED2, and TO and buTOTIN labeled restriction digests. In the taps-NPe(4) buffer, there is no significant mobility shift when complexes are formed with DNA-dye ratios from 100 to 5 bp per dye and very little dye transfer was observed. This property permits accurate multiplex sizing of samples having a wide concentration range simply by mixing the DNA with a dye solution before electrophoresis. This capability is demonstrated by diluting unpurified PCR products 10-, 100-, and 1,000-fold before mixing with a 1 nM TOTO solution and separating these samples with a ΦX174 HAEIII sizing ladder complexed with buTOTIN. Sizing precisions of better than 1% were obtained at all concentrations of target DNA. The mechanism for the increased DNA-dye complex stability and electrophoretic resolution in the taps-NPe(4) buffer is discussed.
- Published
- 1997
- Full Text
- View/download PDF
45. Post-adolescent acne: a review of clinical features.
- Author
-
Goulden V, Clark SM, and Cunliffe WJ
- Subjects
- Acne Vulgaris complications, Acne Vulgaris pathology, Adult, Age Factors, Cicatrix etiology, Female, Humans, Hyperandrogenism complications, Male, Middle Aged, Prospective Studies, Sex Factors, Acne Vulgaris etiology
- Abstract
Acne is usually recognized as a disorder of adolescence. However, the referral of patients over the age of 25 years with acne has significantly increased over the past 10 years. The clinical features of 200 patients over the age of 25 years, referred to our department for treatment of acne, were evaluated with a view to establishing possible aetiological factors. There were 152 (76%) women and 48 (24%) men. The mean age of the patients was 35.5 years (range 25-55 years). The acne was mild or moderate in severity, consisting principally of inflammatory lesions, with mean total acne grade (Leeds Grading Scale) of 1.125 for men and 0.75 for women. Most patients had persistent acne; but true late-onset acne (onset after the age of 25 years) was seen in 28 (18.4%) of women and four (8.3%) of men. Thirty-seven per cent of women had features of hyperandrogenicity. One hundred and sixty-four patients (82%) had failed to respond to multiple courses of antibiotics, and 64 (32%) had relapsed after treatment with one or more courses of isotretinoin. External factors, such as cosmetics, drugs and occupation, were not found to be significant aetiological factors. A family history revealed that 100 (50%) of patients had a first-degree relative with post-adolescent acne. Patients with post-adolescent acne appear to represent an increasingly important population of acne sufferers. External factors do not seem to have a significant aetiological role. Two main clinical groups were identified: those with persistent acne and those with late-onset acne. A minority of women also had features of hyperandrogenicity. These patients, and those with late-onset acne, may represent a subgroup who have underlying abnormalities of ovarian, adrenal or local androgen metabolism, and require separate investigation.
- Published
- 1997
46. DNA sequencing using a four-color confocal fluorescence capillary array scanner.
- Author
-
Kheterpal I, Scherer JR, Clark SM, Radhakrishnan A, Ju J, Ginther CL, Sensabaugh GF, and Mathies RA
- Subjects
- Base Sequence, Electrophoresis, Capillary methods, Humans, Molecular Sequence Data, Sequence Analysis, DNA methods, Sierra Leone, DNA, Mitochondrial chemistry, Electrophoresis, Capillary instrumentation, Sequence Analysis, DNA instrumentation
- Abstract
The design, construction and operation of a four-color capillary array electrophoresis scanner are presented. The use of sensitive energy transfer primers facilitates four-color detection of the DNA sequencing fragments following excitation at a single laser wavelength (488 nm). This scanner collects fluorescence data from up to 25 capillaries in parallel. The resulting four-color image files are automatically reduced to four-color line plots, and a base-calling program (Sax) is used to call the sequence. The performance of this system for DNA sequencing is demonstrated by examining twelve different motifs of the hypervariable region I of human mitochondrial (mt) DNA obtained from a Sierra Leone population.
- Published
- 1996
- Full Text
- View/download PDF
47. A Novel X-ray Diffractometer to Study the Texture of Materials.
- Author
-
Tang CC, Miller MC, Clark SM, Player MA, and Craib GR
- Abstract
An X-ray energy-dispersive diffraction technique to study the texture of materials using synchrotron radiation has been developed. The design and commissioning of the diffraction instrument are described. The technique was first applied to study a drawn-wire aluminum sample which has a well known deformation texture. To demonstrate its capability further, results obtained from an erbium evaporated thin film are also presented.
- Published
- 1996
- Full Text
- View/download PDF
48. Periodontal files--a comparative study.
- Author
-
Pasquini R, Clark SM, Baradaran S, and Adams DF
- Subjects
- Equipment Design, Humans, Microscopy, Electron, Scanning, Surface Properties, Dental Instruments, Dental Scaling instrumentation, Periodontics instrumentation
- Abstract
Periodontal files are used by many dentists for instrumentation of root surfaces as a part of periodontal treatment. The purposes of this study were: 1) to examine, evaluate, and compare several periodontal files in 3 different conditions: new, used, and used/sharpened and 2) to evaluate the efficacy of 5 sharpening devices. The main characteristics observed included: the number, shape, and interval of blades; the active, rake, and lip angles; changes induced by wear; the influence of sharpening; and the type of metal surfaces comprising the blades. There was a wide range of active angles on each individual file, from a high of 75 degrees to a low of 51 degrees. The range of active angles for all blades on all new files was even greater, from a high of 87 degrees to a low of 30 degrees. Wear, observed on some but not all blades, was not extensive and appeared either as abrasion or, occasionally, as fracture of the blade edge. Sharpness scores (5 = sharpest and 1 = dullest) for new file blades were also extremely variable and spanned the full range of values, with a majority of blades scoring 3.5 and below. Attempts to sharpen files with several devices produced inconsistent results. All 5 sharpening devices had significant shortcomings. It was concluded that the extreme ranges both in active angles and in sharpness scores probably have a significant influence on effectiveness of root instrumentation.
- Published
- 1995
- Full Text
- View/download PDF
49. Psychological outcome of ECMO-eligible neonates with severe respiratory failure treated using conventional medical therapy.
- Author
-
Mathias JL, Clark SM, Nettelbeck T, James SL, and White DA
- Subjects
- Adaptation, Psychological, Case-Control Studies, Child Behavior Disorders epidemiology, Child Behavior Disorders etiology, Child Behavior Disorders prevention & control, Child, Preschool, Developmental Disabilities epidemiology, Developmental Disabilities prevention & control, Family Health, Female, Follow-Up Studies, Humans, Hypoxia mortality, Hypoxia therapy, Infant, Infant, Newborn, Male, Mothers psychology, Prevalence, Respiratory Insufficiency mortality, Respiratory Insufficiency therapy, Risk Factors, South Australia epidemiology, Developmental Disabilities etiology, Extracorporeal Membrane Oxygenation, Hypoxia complications, Respiratory Insufficiency complications
- Abstract
Objective: The present study addressed a National Health and Medical Research Council (NHMRC) recommendation that the outcome of neonates who are treated conventionally for respiratory problems be further investigated before setting up additional extracorporeal membrane oxygenation (ECMO) centres in Australia., Methodology: The cognitive and behavioural outcome of ECMO eligible infants who received conventional treatment for respiratory problems at birth was assessed in 18 infants aged 1.5-3 years (index group). ECMO was not available at either of the treating hospitals. Index children were compared to a matched control group of children who did not experience any major complications at birth. Children were assessed using either the Bayley or McCarthy scales of infant development and the Child Behavior Checklist., Results: Overall, a mortality rate of 19% and a psychological morbidity rate of 18% suggest that children born with severe respiratory failure, who meet existing ECMO eligibility criteria, have a good prognosis when treated using conventional medical therapy., Conclusions: Improvements to conventional treatments indicate that ECMO eligibility criteria may need to be revised to identify accurately those infants who are at extreme risk of mortality if treated conventionally.
- Published
- 1995
- Full Text
- View/download PDF
50. Modeling cation/anion-water interactions in functional aluminosilicate structures.
- Author
-
Richards AJ, Barnes P, Collins DR, Christodoulos F, and Clark SM
- Subjects
- Anions chemistry, Calcium Compounds chemistry, Cations chemistry, Computer Simulation, Hydrogen Bonding, Kaolin chemistry, Models, Chemical, Molecular Structure, Monte Carlo Method, Silicates chemistry, Water chemistry, Zeolites chemistry, Aluminum Silicates chemistry, Computer Graphics, Models, Molecular
- Abstract
A need for the computer simulation of hydration/dehydration processes in functional aluminosilicate structures has been noted. Full and realistic simulations of these systems can be somewhat ambitious and require the aid of interactive computer graphics to identify key structural/chemical units, both in the devising of suitable water-ion simulation potentials and in the analysis of hydrogen-bonding schemes in the subsequent simulation studies. In this article, the former is demonstrated by the assembling of a range of essential water-ion potentials. These span the range of formal charges from +4e to -2e, and are evaluated in the context of three types of structure: a porous zeolite, calcium silicate cement, and layered clay. As an example of the latter, the computer graphics output from Monte Carlo computer simulation studies of hydration/dehydration in calcium-zeolite A is presented.
- Published
- 1995
- Full Text
- View/download PDF
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