Search

Clinical studies have suggested that the enumeration of mycobacteria by using automated liquid systems is a faster and simpler alternative to quantitative cultures. Here, we show that the time to detection of M. tuberculosis growth as measured with the MGIT 320 liquid culture system inversely correlates with CFU determinations from culture on solid media and that mycobacterial quantification using the MGIT system is faster and easier to perform than CFU plating.

The trunk muscle transversus abdominis (TrA) is thought to be controlled independently of the global trunk muscles. Methodological issues in the 1990s research such as unilateral electromyography and a limited range of arm movements justify a re-examination of this theory. The hypothesis tested is that TrA bilateral co-contraction is a typical muscle synergy during arm movement. The activity of 6 pairs of trunk and lower limb muscles was recorded using bilateral electromyography during anticipatory postural adjustments (APAs) associated with the arm movements. The integrated APA electromyographical signals were analyzed for muscle synergy using Principle Component Analysis. TrA does not typically bilaterally co-contract during arm movements (1 out of 6 participants did). APA muscle activity of all muscles during asymmetrical arm movements typically reflected a direction specific diagonal pattern incorporating a twisting motion to transfer energy from the ground up. This finding is not consistent with the hypothesis that TrA plays a unique role providing bilateral, feedforward, multidirectional stiffening of the spine. This has significant implications to the theories underlying the role of TrA in back pain and in the training of isolated bilateral co-contraction of TrA in the prophylaxis of back pain., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Lymphoma arising from the skin is the second most common site of extra-nodal non-Hodgkin's lymphoma. Over the last 25 years, the incidence has been rising. There is now a new World Health Organization/European Organization for Research and Treatment of Cancer joint classification for cutaneous lymphomas and new proposed International Society for Cutaneous Lymphomas/European Organization for Research and Treatment of Cancer staging systems. This overview examines the role of radiotherapy in the current management of cutaneous T- and B-cell lymphomas encompassing technological advances, new systemic therapies and novel radio-enhancing therapies now available. Modern total skin electron beam radiotherapy and the current low-dose and combination approaches are reviewed. Radiotherapy has remained the most successful treatment for cutaneous lymphoma over the last 50 years and with the technological advances and combination approaches available now and in the future will remain so for the next 50 years., (Copyright © 2012. Published by Elsevier Ltd.)

Aims: Chemoradiation is the standard of care for the treatment of anal canal cancer, with surgery reserved for salvage. For tumours with uninvolved inguinal nodes, it is standard to irradiate the inguinal nodes prophylactically, resulting in large field sizes, which contribute to acute and late toxicity. The aim of this single-centre retrospective study was to determine if, in selected cases, prophylactic inguinal nodal irradiation could be avoided., Materials and Methods: Between August 1998 and August 2004, 30 patients with biopsy-proven squamous cell anal canal cancer were treated with chemoradiation using one phase of treatment throughout. A three-field beam arrangement was used without attempting to treat the draining inguinal lymph nodes prophylactically. The radiotherapy dose prescribed was 50Gy in 25 daily fractions over 5 weeks. Concomitant chemotherapy was delivered with the radiation using mitomycin-C 7-12mg/m(2) on day 1 and protracted venous infusional 5-fluorouracil 200mg/m(2)/day throughout radiotherapy., Results: All patients had clinically and radiologically uninvolved inguinal and pelvic nodes and all had primary lesions that were T3 or less. The median age at diagnosis was 65 years (range 41-84). The median follow-up was 41 months (range 24-113). The mean posterior field size was 14x15cm and the mean lateral field size was 12x15cm. All patients achieved a complete response. Ninety-four per cent of patients (28/30) were alive and disease free. The two patients who died did so of unrelated causes and were disease free at death. Four patients relapsed and all were salvaged with surgery; two for local disease requiring abdominoperineal resection, one with an inguinal nodal relapse requiring inguinofemoral block dissection and one for metastatic disease to the liver who underwent liver resection., Conclusions: This single-centre retrospective study supports the treatment for selected cases of anal canal cancer with smaller than standard radiation fields, avoiding prophylactic inguinal nodal irradiation. Hopefully this will translate into reduced acute and late toxicity. In future studies we would suggest that consideration is given as to whether omission of prophylactic inguinal nodal irradiation for early stage tumours should be explored.

Anticipatory postural adjustments (APAs) are postulated to ameliorate the effects of the disturbance to posture caused by voluntary movement. The primary hypothesis tested in our study was that the magnitude of anticipatory trunk muscle activity is altered by abdominal muscle fatigue. A subsidiary aim of the present study was to examine the directional nature of APAs and use this information to elucidate the central or peripheral nature of changes in postural muscle activity associated with abdominal muscle fatigue. The present study was a within subject design, where abdominal muscle fatigue was induced by a static abdominal curl. Surface EMG was used to assess postural muscle activity in the following trunk muscles; rectus abdominis, erector spinae and internal oblique. Following abdominal muscle fatigue, the magnitude of muscle activity during APAs was significantly reduced by 20% in both the rectus abdominis (fatigued muscle) and the erector spinae (not fatigued) indicating a central rather than peripheral fatigue effect on muscle activity. Abdominal muscle fatigue also induced a 30% increase in the baseline muscle activity of the internal oblique. The changes in magnitude of APA muscle activity may reflect a change in system gain or a change in postural control perhaps related to a change in perceived postural stability. An increase in baseline muscle activity in the internal oblique may compensate partially for the reduction in APAs., (Copyright 2005 Elsevier B. V.)

Post-implantation dosimetry is an important element of permanent prostate brachytherapy. This process relies on accurate localization of implanted seeds relative to the surrounding organs. Localization is commonly achieved using CT images, which provide suboptimal prostate delineation. On MR images, conversely, prostate visualization is excellent but seed localization is imprecise due to distortion and susceptibility artefacts. This paper presents a method based on fused MR and x-ray images acquired consecutively in a combined x-ray and MRI interventional suite. The method does not rely on any explicit registration step but on a combination of system calibration and tracking. A purpose-built phantom was imaged using MRI and x-rays, and the images were successfully registered. The same protocol was applied to three patients where combining soft tissue information from MRI with stereoscopic seed identification from x-ray imaging facilitated post-implant dosimetry. This technique has the potential to improve on dosimetry using either CT or MR alone.

Aims: The role of postoperative radiotherapy and hormone treatment after radical prostatectomy is uncertain, with no good evidence base to guide practice. In particular, it is not known whether a blanket policy of adjuvant therapy offers any advantage over a selective approach using salvage treatment in people who develop biochemical failure. Furthermore the technique for postoperative radiotherapy to the prostate bed has not been well described. We surveyed the opinion of UK clinical oncologists to describe current practice, with a view to informing the design of clinical trials in this setting., Materials and Methods: A questionnaire was designed to elicit the opinion and clinical practice of UK clinical oncologists on the use of radiotherapy and hormone therapy after radical prostatectomy. The questionnaire was distributed to the delegates at the British Institute of Radiology Conference 'Contemporary issues in Prostate Cancer Radiotherapy' on 9 May 2003., Results: Forty-nine out of 70 (70%) clinical oncologists completed the questionnaire. With an undetectable postoperative prostate-specific antigen (PSA) less than 0.04 ng/ml, opinion was divided on the role of adjuvant therapy. For example, adjuvant radiotherapy was recommended by 51% (25/49) of respondents for cases with pT3 margin positive disease. When recommending adjuvant radiotherapy, 60% (59/99) recommended hormone therapy in addition. In cases with an asymptomatic rising PSA after radical prostatectomy who had not received adjuvant therapy, 93% (43/46) recommended salvage radiotherapy, but the PSA threshold for recommending such treatment varied widely. The two most common dose-fractionation regimens for salvage radiotherapy to the prostate bed were 62-64 Gy in 2 Gy daily fractions (47%), and 50-55 Gy in 20 fractions (30%)., Conclusions: Opinion is varied within the UK on the role of radiotherapy and hormone therapy after radical prostatectomy. The results of this survey should inform the design of future clinical trials.

The emergence of drug-resistant strains of Mycobacterium tuberculosis is a serious public health problem. Many of the specific gene mutations that cause drug resistance in M. tuberculosis are point mutations. We are developing a PCR-peptide nucleic acid (PNA)-based ELISA as a diagnostic method to recognize point mutations in genes associated with isoniazid and rifampin resistance in M. tuberculosis. Specific point mutation-containing sequences and wild-type sequences of cloned mycobacterial genes were PCR-amplified, denatured, and hybridized with PNA probes bound to microplate wells. Using 15-base PNA probes, we established the hybridization temperatures (50 degrees C-55 degrees C) and other experimental conditions suitable for detecting clinically relevant point mutations in the katG and rpoB genes. Hybridization of PCR-amplified sequences that contained these point mutations with complementary mutation-specific PNAs resulted in significant increases in ELISA response compared with hybridization using wild-type-specific PNAs. Conversely, PCR-amplified wild-type sequences hybridized much more efficiently with wild-type PNAs than with the mutation-specific PNAs. Using the M. tuberculosis cloned genes and PCR-PNA-ELISA format developed here, M. tuberculosis sequences containing point mutations associated with drug resistance can be identified in less than 24 h.

Setting: The diagnosis of extra-pulmonary tuberculosis (EPTB) remains an important clinical problem, primarily because of the inadequate sensitivity of conventional bacteriologic methods for detecting Mycobacterium tuberculosis in extra-pulmonary specimens., Objective: To evaluate whether a IS6110-based polymerase chain reaction (PCR) method can be utilized to detect M. tuberculosis in non-pulmonary specimens., Design: Specimens from 286 Mexican patients with a presumptive clinical diagnosis of EPTB were prospectively examined by Ziehl-Neelsen staining, mycobacterial culture on Löwenstein-Jensen slants, and by PCR. The DNA for PCR was extracted by the buffer lysis method and phenol-guanidine thiocyanate-chloroform. Primers that amplify a 200 bp fragment from the insertion-like M. tuberculosis sequence element IS6110 were utilized., Results: Our results demonstrate that this PCR method is highly specific (100%) for identifying M. tuberculosis from a variety of specimens including cerebrospinal fluid (CSF), pleural fluid, ascitic fluid, pericardial fluid, urine, and lymph node exudate. Moreover, the sensitivity of PCR for detecting M. tuberculosis in CSF (94%), pleural fluid (94%), ascitic fluid and other extrapulmonary specimens (93%) greatly exceeds the sensitivity of conventional smear and culture methods., Conclusion: These results demonstrate that PCR can be a highly specific and sensitive aid in the detection of M. tuberculosis from extra-pulmonary specimens.

PSA is currently being used to detect and monitor quantitatively the development of prostate cancer by serum levels of PSA and has also been found to be present in high concentrations in semen. Elegantly simple, sensitive, and reproducible methods have been developed for analysis of the presence of PSA, including the Tandem-E PSA Immunoenzymetric Assay. The most common procedures for the forensic identification of semen have focused on the microscopic detection of sperm, acid phosphatase activity, and immunoelectrophoretic methods for the detection of PSA. Although these methods have been used for many years, there are problems associated with each method. The Tandem-E PSA Immunoenzymetric Assay detected PSA in 100% of the forensic casework fabric samples, 80% of the forensic casework vaginal swabs and 100% of the vasectomized individuals tested. The cut-off value was determined to be 1.77 ng/mL. These results indicate that this method can be used to identify the presence of semen in forensically significant specimens.

The mechanisms by which heparin protects the liver during induced episodes of liver ischemia-reperfusion are poorly understood. Previous work in a swine model demonstrated that serum levels of glycohydrolases and lipid peroxide peaked within 3 h after 45 minutes of hepatic ischemia followed by reperfusion. Serum levels of lactate dehydrogenase and aspartate aminotransferase peaked 20-24 h later. The aim of this study was to evaluate the effect of heparin on these two-phases of enzyme release, using a pig model of hepatic ischemia-reperfusion injury. Twenty male swine were divided into control (n = 8) and heparin (n = 12) groups. In the heparin group, heparin was administered prior to and concurrent with ischemia-reperfusion. Following 45 min of hepatic ischemia, the levels of beta-galactosidase, beta-glucosidase, acid phosphatase, purine nucleoside phosphorylase, lipid peroxides, lactate dehydrogenase, and aspartate aminotransferase in serum were monitored for up to 166 h and compared to pre-ischemic and control levels. With heparin infusion, the peak levels of beta-galactosidase, beta-glucosidase, and the lipid peroxide were reduced to 50-60% of the control levels. Acid phosphatase and purine nucleoside phosphorylase activities in serum were reduced to 25% and 60%, respectively. The peak concentrations of lactate dehydrogenase and aspartate aminotransferase were reduced to about 25% of the control level. In addition, the serum enzymes of control pigs did not return to pre-ischemic levels until 2 weeks after hepatic ischemia, while they normalized in less than 1 week in the heparin-treated animals. Systemic heparinization had different protective effects on the first and secondary phases of liver injury. These differences may reflect heparin protection of different types of liver cells. The protection of the parenchymal cells may be the combined result of reduced sinusoidal cell injury and the anticoagulant properties of heparin.

The development of novel vaccines for use in the prevention and immunotherapy of tuberculosis is an area of intense interest for scientific researchers, public health agencies and pharmaceutical manufacturers. Development of effective anti-tuberculosis vaccines for use in specific target populations will require close cooperation among several different international organizations including agencies responsible for evaluating the safety and effectiveness of new biologics for human use. In this review, the major issues that are addressed by regulatory agencies to ensure that vaccines are pure, potent, safe, and effective are discussed. It is hoped that the comments provided here will help accelerate the development of new effective vaccines for the prevention and treatment of tuberculosis.

Recent studies examining the molecular mechanisms of isoniazid (INH) resistance in Mycobacterium tuberculosis have demonstrated that a significant percentage of drug-resistant strains are mutated in the katG gene which encodes a catalase-peroxidase, and the majority of these alterations are missense mutations which result in the substitution of a single amino acid. In previous reports, residues which may be critical for enzymatic activity and the drug-resistant phenotype have been identified by evaluating INH-resistant clinical isolates and in vitro mutants. In this study, site-directed mutagenesis techniques were utilized to alter the wild-type katG gene from M. tuberculosis at 13 of these codons. The effects of these mutations were determined using complementation assays in katG-defective, INH-resistant strains of Mycobacterium smegmatis and Mycobacterium bovis BCG. This mutational analysis revealed that point mutations in the katG gene at nine of the 13 codons can cause drug resistance, and that enzymatic activity and resistance to INH are inversely related. In addition, mutations in the mycobacterial catalase-peroxidase which reduce catalase activity also decrease peroxidase activity.

Mutations that eliminate KatG catalase-peroxidase activity prevent activation of isoniazid and are a major mechanism of resistance to this principal drug for the treatment of Mycobacterium tuberculosis infections. However, the loss of KatG activity in clinical isolates seemed paradoxical because KatG is considered an important factor for the survival of the organism. Expression of either KatG or the recently identified alkyl hydroperoxidase AhpC was sufficient to protect bacilli against the toxic effects of organic peroxides. To survive during infection, isoniazid-resistant KatG mutants have apparently compensated for the loss of KatG catalase-peroxidase activity by a second mutation, resulting in hyperexpression of AhpC.

In the United States, disseminated infection with environmental mycobacteria, including the Mycobacterium avium complex, is the most common opportunistic bacterial infection seen in AIDS patients. However, the source and relative degree of exposure to environmental mycobacteria during childhood are unknown. To examine the age-related exposure to mycobacteria, we obtained serum samples from 150 children ranging in age from 6 months to 18 years. Each sample was tested against both M. avium (serovar 1) sonic extracts and mycobacterial lipoarabinomannan, using an enzyme-linked immunosorbent assay (ELISA). All serum samples were also subjected to immunoblot analysis with the sonic extract antigen. These studies established that elevated ELISA values (P < 0.0001) and increased immunoblot reactivity (P < 0.0001) against mycobacterial antigens were both associated with increasing age. The seroreactivity differences were most striking when comparing the age groups of children below the age of 6 with the older age groups. Our results suggest that the development of humoral immune responses to mycobacterial antigens in children correlates with increasing age and that there may be an environmental factor predisposing to mycobacterial exposure which is related to advancing age.

To better understand the regulation of insulin-like growth factor binding protein-5 (IGFBP-5) expression, we cloned the IGFBP-5 gene from human genomic libraries and identified a region in the 5' flanking sequence which functions as a promoter. The human IGFBP-5 gene is divided into four exons which, primarily due to a first intron of approximately 25 kilobases, span approximately 33 kilobases of DNA. Southern analysis identified a single copy of the IGFBP-5 gene in the haploid human genome, and several independent mapping strategies found this gene tightly linked with, and in opposite transcriptional orientation to, the IGFBP-2 gene at chromosomal region 2q33-34. Primer extension studies identified the IGFBP-5 mRNA cap site 772 base pairs (bp) 5' to the first nucleotide of the translation start codon. Analysis of the 5'-flanking sequence identified a potential TATA element beginning 33 bp 5' to the mRNA cap site. When a DNA fragment containing this cap site and 461 bp of upstream sequence was placed 5' to the chloramphenicol acetyltransferase reporter gene and transfected into MDA-MB-468 human breast cancer cells, it directed chloramphenicol acetyltransferase expression in an orientation-specific manner, suggesting that this region contains elements essential for IGFBP-5 promoter activity.

Infection caused by Mycobacterium avium is the major cause of bacteremia in patients with AIDS. A critical event in the initiation of a variety of bacterial infections is the adherence of bacteria to host cell surfaces, which is often brought about by the interaction of specific molecules on the bacterial surface with host cell surface receptors. In the present study, a sonicate of M. avium was used to isolate monocyte-binding proteins by affinity chromatography with CNBr-Sepharose-4B coupled to extracts of monocytes. A 68 kd protein present on the surface of M. avium was identified as one of nine monocyte-binding proteins. This protein was isolated and further characterized. The N-terminal amino acid sequence (22 residues) of the protein was determined and was found to exhibit strong homology with the 65 kd heat shock proteins of M. tuberculosis, M. leprae, and M. bovis. However, a previously characterized monoclonal antibody directed against a 66 kd antigen of M. avium was found to cross-react with the 68 kd protein from M. avium but not with the 65 kd proteins from M. leprae and M. bovis, suggesting that the 68 kd antigen may differ from the 65 kd proteins of M. leprae and M. bovis with respect to certain epitopes. In an in vitro inhibition assay, the 68 kd protein was found to compete with the attachment of intact fluorescein isothiocyanate-labeled M. avium to monocyte-derived macrophages, inhibiting this attachment in a dose-dependent manner up to 42%. The 65 kd proteins of M. leprae and M. bovis, on the other hand, did not appear to inhibit this attachment substantially (13.9% and 14.6%, respectively). These results suggest that the 68 kd protein of M. avium may be involved in binding to receptors on macrophages and help in the attachment of the organism to its host cell.

Occupational safety and health encompasses four core disciplines: industrial hygiene, occupational safety, occupational medicine, and occupational health nursing. This chapter traces the growth of these specialties throughout the 20th century in response to growing demands of the workplace. Graduate and certification programs are described for each of these four areas.

The recent emergence of indolent and rapidly fatal drug-resistant strains of Mycobacterium tuberculosis has renewed interest in defining the molecular mechanisms of drug resistance in the tubercle bacilli. In this report, we have examined the mechanism of resistance to streptomycin (Sm) in M. tuberculosis through the cloning and nucleotide sequence analysis of the gene encoding the ribosomal S12 protein (rpsL gene) from streptomycin-resistant strains and their streptomycin-sensitive parental strains. We have demonstrated that five singly SmR M. tuberculosis strains and an SmR isolate that has reduced sensitivity to multiple antibiotics have identical point mutations at codon 43 of the rpsL gene. Mutations at this same site confer SmR in Escherichia coli. In contrast, two other multiple drug-resistant M. tuberculosis strains that are resistant to Sm have rpsL genes that have the same nucleotide sequence as their drug-sensitive parent strains, suggesting that different resistance mechanisms are involved in these strains.

The regulation of insulin-like growth factor binding protein-1 (IGFBP-1) by its ligands, IGF-I and IGF-II, was studied in continuous cultures of HepG2 human hepatoma cells. Both IGF-I and IGF-II in concentrations as low as 1-10 nmol/l caused significant suppression of IGFBP-I protein levels. This suppression was accompanied by decreased IGFBP-1 mRNA levels occurring within 2-4 h of exposure to IGF-I or IGF-II, and by a significant decrease in IGFBP-1 promoter activity. IGF-I and IGF-II were equipotent in suppressing basal levels of IGFBP-1 protein, mRNA and promoter activity. IGF-I, IGF-II, and IGF-analogs with low IGFBP-1 affinity, (des 1-3)IGF-I and long R3IGF-I, all potently suppressed the previously characterized increase in IGFBP-1 protein levels and promoter activity induced by cAMP and theophylline. In contrast, [Leu-27]IGF-II, which interacts with the type II but not type I IGF receptor, had no effect on IGFBP-1 protein levels or promoter activity. Our data indicate that IGFBP-1 production is inhibited by its ligands, IGF-I and IGF-II, and that this effect is probably mediated at the transcriptional level. The effects of IGF-I and IGF-II apparently occur as a result of binding to the type I IGF receptor, and are similar to the previously characterized suppressive effects of insulin on IGFBP-1 transcription mediated through the insulin receptor. When considered with previous data regarding expression of IGFBP-1 and the type I IGF receptor, our results suggest that IGF regulation of IGFBP-1 may play an as yet undefined role in fetal development and postnatal hepatic regeneration.

We report the case of a 63-year-old woman whose indwelling urethral catheter became blocked regularly at 4-5 day intervals over a period of 10 weeks. 'Worm-like' structures 25-30 cm in length were found either in the catheter, completely occluding the lumen, or in the drainage tube thereby blocking the valve of the drainage bag. Electron microscopy showed that these structures were composed of bacteria, while culture revealed them to be mixed communities of Pseudomonas aeruginosa, Escherichia coli, Enterococcus faecalis and Proteus mirabilis. Following treatment with ciprofloxacin, catheter drainage continued freely for a further period of 10 weeks.

Insulin inhibits the hepatic transcription of insulin-like growth factor binding protein-1 (IGFBP-1). In the present studies, human HEP G2 hepatoma cells were transiently transfected with human IGFBP-1 gene promoter constructs in order to identify cis elements and trans-acting factors that confer the insulin effect. Transfections of IGFBP-1 promoter deletion constructs localized an insulin responsive element (IRE) between approximately 140- and approximately 103-base pair (bp) 5' to the mRNA capsite. This region contains a 25-bp sequence which is 100% conserved in the rat IGFBP-1 promoter and which has two AT-rich, 8-bp elements exhibiting dyad symmetry. Site-directed mutagenesis of both elements in the same 1205-bp IGFBP-1 promoter construct abolished the inhibitory effect of insulin on promoter activity. Also, the native but not the mutant IGFBP-1 IRE conferred the inhibitory effect of insulin to the heterologous thymidine kinase promoter. Gel mobility shift assays identified a DNA binding activity which specifically binds the native IGFBP-1 IRE and which is not altered by prior insulin treatment. The IGFBP-1 IRE sequence is similar to those of functionally mapped IREs from other gene promoters, suggesting that this common IRE and the protein(s) which it binds confer the insulin effect to a number of insulin-sensitive genes.

This report examines the effects of inhibitors of cell proliferation on transforming growth factor alpha (TGF-alpha) expression in low-density cultures of poorly (PD) and well-differentiated (WD) human colon carcinoma cells, continuously maintained in serum-free medium. In contrast to results in certain untransformed cells, growth inhibitors such as transforming growth factor beta 1 (TGF-beta 1) and N,N-dimethylformamide up-regulated TGF-alpha mRNA and protein expression in these human colon carcinoma cells. Treatment of low-density WD cells with TGF-beta 1 (10 ng/ml) resulted in a 1.5-fold increase in TGF-alpha mRNA levels within 4 h of treatment. TGF-alpha mRNA levels increased to 2.7-fold above control values by 48 h after TGF-beta 1 addition. Additionally, over a TGF-beta 1 concentration range of 1-30 ng/ml, TGF-alpha protein levels were increased by 2-10-fold, despite the fact that the growth of the WD cells remained inhibited. Although TGF-beta 1 control of TGF-alpha expression was altered in these WD colon carcinoma cells, relative to that in untransformed cells previously examined, the cells retained the ability to up-regulate TGF-alpha expression in an epidermal growth factor-dependent manner. In similarity to the results with TGF-beta 1 in WD colon carcinoma cells, the differentiation agent N,N-dimethylformamide (0.7%) resulted in an increase of TGF-alpha mRNA of approximately 3.8-fold in PD colon carcinoma cells, as well as a 4.4-fold increase in TGF-alpha protein after 4 days of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycobacterial disease remains a serious international public health concern. Improved methods to rapidly and specifically detect mycobacterial infections would greatly enhance clinical management of these diseases. To define species-specific T cell epitopes that may be useful for the immunodiagnosis of mycobacterial infections, polymerized synthetic peptides from the 19-kD Mycobacterium tuberculosis and Myco. intracellulare protein homologues were tested in guinea pig DTH assays. Five Myco. tuberculosis and eight Myco. intracellulare peptides evoked skin test responses. Although all of the active Myco. tuberculosis and seven of the Myco. intracellulare peptides elicited non-specific DTH reactions, the peptide IN13 induced a Myco. intracellulare-specific skin test reaction, and thus represents a specific Myco. intracellulare T cell DTH epitope. This result suggests that the development of monospecific peptide-based immunodiagnostic reagents may be feasible for future clinical use.

Insulin-like growth factor binding protein-1 (IGFBP-1) serum levels are increased by glucocorticoids and glucagon, and are decreased by insulin; these effects seem to reflect changes in hepatic IGFBP-1 expression. Human HEP G2 hepatoma cells respond to cAMP or insulin with stimulation or inhibition of IGFBP-1 expression, respectively; however, dexamethasone alone does not stimulate IGFBP-1 expression. Studies presented here show that in the presence of cAMP and theophylline, nontransfected HEP G2 cells respond to further addition of dexamethasone with a approximately 70% rise in IGFBP-1 mRNA levels, and HEP G2 cells transfected with IGFBP-1 promoter constructs respond to further addition of dexamethasone with a approximately 70% rise in IGFBP-1 protein levels and a approximately 9-fold rise in IGFBP-1 promoter activity. The stimulatory effect of dexamethasone and cAMP, conferred to the IGFBP-1 promoter between 357 and 103 base pairs 5' to the mRNA cap site, is inhibited by insulin. Thus, the cis elements necessary to confer multihormonal regulation of IGFBP-1 expression appear to reside in a short stretch of DNA just upstream from the IGFBP-1 transcription start site.

Untransformed rat intestinal epithelial cells (IEC-18) were chemically mutagenized, selected in the presence of TGF beta 1, and cloned by limiting dilution. Two clones (4-5, 4-6) were resistant to growth inhibition by both TGF beta 1 and TGF beta 2. Another clone (4-1) was more sensitive to both TGF beta isoforms (relative to parental IEC-18 cells). IC50 values for TGF beta 1 and 2 in the 4-1 cells were at least 1/9 those of the parental cells; growth rates were reduced by 49% for TGF beta 1 and by 26% for TGF beta 2 in this clone. This increased sensitivity to TGF beta was explained by the 5- to 10-fold increase, relative to parental cells, in binding of TGF beta 1 and TGF beta 2 to both the type I and II receptors. In contrast, the resistance to growth inhibition by TGF beta in the 4-5 and 4-6 cells could not be explained by a decrease in either TGF beta binding affinities or in total number of receptors expressed, by the presence of serum binding components, or by occupation of receptor binding sites with autocrine TGF-beta 1. However, in comparison to TGF beta-sensitive cells (IEC-18, 4-1), the resistant cells displayed a higher ratio of type II relative to type I receptor binding by TGF-beta 1. Thus, a critical ratio of binding to receptor subtypes correlated with growth inhibition by TGF-beta 1. Resistance to TGF-beta 2 in the same clones did not appear to be receptor related. Thus, different mechanisms for resistance to TGF-beta 1 and TGF-beta 2 were observed within a given clone.

Disseminated Mycobacterium avium/Mycobacterium intracellulare complex (MAC) disease is a frequent complication in patients with the acquired immune deficiency syndrome (AIDS). In this report, we present the nucleotide sequence of the M. intracellulare MI22 gene. Computer sequence comparisons reveal that the MI22 gene, which encodes a serologically active protein, has 78% DNA sequence identity and 77% protein sequence identity with the seroreactive 19 kDa Mycobacterium tuberculosis lipoprotein antigen. Southern blot hybridizations indicate that an MI22 gene probe binds similar-sized restriction fragments in M. tuberculosis and M. intracellular genomic DNA. In addition, immunoblot analyses demonstrate that MI22 is recognized by sera from tuberculosis patients. These data further support the existence of 19 kDa MAC and M. tuberculosis protein homologues. Phase partitioning experiments and the presence of a consensus lipid modification site in the deduced MI22 protein sequence strongly suggest that M122 is also a lipoprotein. Comparative analyses of these mycobacterial antigenic homologues may provide the basis for the design of species-specific diagnostic reagents.

The immunoreactivity of four recombinant Mycobacterium intracellulare beta-galactosidase fusion proteins, which correspond to 22, 40, 43 and 85 kDa M. intracellulare antigens, was assessed. Lymphoproliferative assays demonstrated that Escherichia coli lysates containing each of the fusion proteins stimulated T cells in vitro. Purified preparations of three of these recombinant M. intracellulare antigens (22, 43 and 85 kDa) also induced delayed-type hypersensitivity (DTH) reactions in sensitized guinea pigs. However, the skin test responses evoked by each of these antigens was not species-specific. Given these results, the potential utility as skin test reagents of the purified antigens or peptides derived from these proteins is discussed.

The transforming growth factor beta (TGF beta) family members are ubiquitously expressed and control a variety of cellular processes by interacting with at least two types of high affinity cell surface receptors. However, the primary signal transduction mechanism of the receptors is unknown. The ras-encoded 21-kDa GTP binding proteins have recently been shown to mediate the effects of other polypeptide growth factors. Here we show that both TGF beta 1 and TGF beta 2 (5 ng/ml) result in a rapid (within 6 or 12 min, respectively) stimulation of GTP bound to p21ras in TGF beta-sensitive intestinal epithelial cells. Further, the CCL64 epithelial cell line, extremely sensitive to growth inhibition by TGF beta, displayed a concentration-dependent increase in GTP bound to p21ras by TGF beta 1 and a rapid activation of p21ras by TGF beta 2. The results provide the first direct evidence for rapid activation of a receptor coupling component for TGF beta in epithelial cells.

The plasmid profiles of 12 Mycobacterium avium strains isolated from 12 different patients with acquired immunodeficiency syndrome were analysed. Plasmids were identified in 9 of these strains. Plasmids were isolated from all 7 serovars 4 and 8 strains, a serovar 20a strain and an untypeable strain, but were not detected in either of 2 serovar 3b strains or an untypeable isolate. Southern blot hybridisations revealed that extracts derived from all of the plasmid-containing strains hybridised to a DNA probe prepared from known mycobacterial plasmid sequences. However, restriction analyses suggest that native plasmids which hybridised to the DNA probe and were similar in mass were not identical.

Health care workers are exposed to an array of physical, chemical, biological, and psychosocial hazards. At a national conference in Seattle May 11-13, 1983, hospital occupational medicine programs were characterized as lagging far behind those in industries with comparable illness and injury rates. Participants and speakers recommended that health care workers be trained to recognize occupational hazards; that epidemiologic, laboratory, and clinical studies be undertaken to discern trends and establish the mechanisms of effects from hazardous exposures; and that adequate employee health and safety programs be established in health care settings.

Nineteen patients with ARDS or pneumonia who were ventilated with PcIRV on the Siemens-Elema Servo 900 C were retrospectively reviewed. The PcIRV reduced peak airway pressure, PEEP, increased Paw, and improved ventilation and oxygenation in these patients. When these patients were compared with themselves on prior conventional IPPV, all had a decrease in PIP, an increase in Paw and most had a decrease in VE, with no change in PaCO2 and an increase in PaO2. The increase in Paw may have contributed to this improved arterial oxygenation. High levels of PIP and PEEP during IPPV have been identified as risk factors in the development of barotrauma and residual parenchymal pulmonary damage. We propose that PcIRV allows for adequate ventilation and oxygenation with decreases in PIP, extrinsically added PEEP and inspired O2 concentration. This mode of ventilation may decrease the morbidity associated with IPPV utilizing high PIP and PEEP.