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Natural products (NPs) are primarily recognized as privileged structures to interact with protein drug targets. Their unique characteristics and structural diversity continue to marvel scientists for developing NP-inspired medicines, even though the pharmaceutical industry has largely given up. High-performance computer hardware, extensive storage, accessible software and affordable online education have democratized the use of artificial intelligence (AI) in many sectors and research areas. The last decades have introduced natural language processing and machine learning algorithms, two subfields of AI, to tackle NP drug discovery challenges and open up opportunities. In this article, we review and discuss the rational applications of AI approaches developed to assist in discovering bioactive NPs and capturing the molecular "patterns" of these privileged structures for combinatorial design or target selectivity.

Category five hurricanes Irma and Maria (September 2017) caused significant damage to shallow seagrass communities across Puerto Rico. The magnitude and spatial extent of hurricane impacts on representative seagrass habitats of Culebra Island were addressed using a combination of random photo-quadrats and before–after hurricanes GIS-based imagery analyses. There was a significant loss of shallow seagrasses across all nine surveyed locations. Most of the documented impacts were associated with sediment bedload (horizontal transport), which resulted in burial and suffocation. There was also localized physical disruption of the seagrass habitat matrix across locations exposed to stronger wave action, creating major scars and exposing below-ground structure to further disintegration by future storm events. Displaced coral rubble also caused seagrass burial. Aerial imagery analyses (2007, 2010, 2017) showed a significant decline in seagrass percent cover. Seagrass decline was positively correlated with wave exposure (p

A method for plastic material classification using a negative-order-resonance (NOR) sensor operating at the 2.5 GHz band and support-vector-machine (SVM) for pattern recognition is presented. The proposal experimentally demonstrates the correct classification of different plastic materials based on their dielectric properties, dealing with large sources of uncertainty introduced by pellet measurements such as air gaps and position/dimension of the pellets. The proposed technique results attractive for the plastic industry as it involves a fast and nondestructive process along with the use of small circuit elements.

In light of the emerging field of Epi-informatics, ie, computational methods applied to epigenetic research, molecular docking, and dynamics, pharmacophore and activity landscape modeling and QSAR play a key role in the development of modulators of DNA methyltransferases (DNMTs), one of the major epigenetic target families. The increased chemical information available for modulators of DNMTs has opened up the avenue to explore the epigenetic relevant chemical space (ERCS). Herein, we discuss recent progress on the identification and development of inhibitors of DNMTs as potential epi-drugs and epi-probes that have been driven by molecular modeling and chemoinformatics methods. We also survey advances on the elucidation of their structure-activity relationships and exploration of ERCS. Finally, it is illustrated how computational approaches can be applied to identify modulators of DNMTs in food chemicals.

Bilioenteric fistulas are the abnormal communication between the bile duct system and the gastrointestinal tract that occurs spontaneously and is a rare complication of an untreated gallstone in the majority of cases. These fistulas can cause diverse clinical consequences and in some cases be life-threatening to the patient.To identify the incidence of bilioenteric fistula in patients with gallstones, its clinical presentation, diagnosis through imaging study, surgical management, postoperative complications, and follow-up.A retrospective study was conducted to search for bilioenteric fistula in patients that underwent cholecystectomy at our hospital center due to cholelithiasis, cholecystitis, or cholangitis, within a 3-year time frame.Four patients, 2 men and 2 women, were identified with cholecystoduodenal fistula. Their mean age was 81.5 years. Two of the patients presented with acute cholangitis and 2 presented with bowel obstruction due to gallstone ileus. All the patients underwent surgical treatment and the diagnostic and therapeutic management of each of them was analyzed.The incidence of cholecystoduodenal fistula was similar to that reported in the medical literature. It is a rare complication of gallstones and its diagnosis is difficult due to its nonspecific symptomatology. It should be contemplated in elderly patients that have a contracted gallbladder with numerous adhesions.

This study explores whether male and hermaphrodite plants of Phillyrea angustifolia (Oleaceae) show physiological and structural differences at the leaf level under severe water stress driven by drought and soil salinity. Leaf traits were measured in summer, at the height of the summer drought period, in male and hermaphrodite plants from two adjacent sites under contrasting soil salinity levels. Male plants from the saline site had significantly higher leaf proline content compared to males from the nonsaline site. By contrast, leaf proline levels were similarly low in hermaphrodite plants from both sites. On the other hand, hermaphrodite plants from the saline site had higher leaf stomatal frequency than hermaphrodites from the nonsaline site, whereas this parameter did not differ for male plants across sites. Such differences could be interpreted as the result of two different solutions to the same selective pressure in the androdioecious shrub P. angustifolia.

We present a new analytical direct parameter-extraction methodology for obtaining the small-signal equivalent circuit of HBTs. It is applied to cryogenically operated SiGe HBTs as a means to allow circuit design of SiGe HBT low-noise amplifiers for cooled radio astronomy applications. We split the transistor into an intrinsic transistor (IT) piece modeled as a Pi-topology, and the quasi-intrinsic transistor (QIT), obtained from the IT after that the base resistance (Rb) has been removed. The relations between Z-Y-parameters of the IT and QIT are then established, allowing us to propose a new methodology for determining Rb. The present extraction method differs from previous studies in that each of the model elements are obtained from exact equations that do not require any approximations, numerical optimization, or post-processing. The validity of this new extraction methodology is demonstrated by applying it to third-generation SiGe HBTs operating at liquid-nitrogen temperature (77 K) across the frequency range of 2-22 GHz.

In this paper we present experimental results for some microwave and millimeter-wave planar structures from room temperature to 10°K. The structures are designed and electromagnetically analyzed by means of two of the most popular EM software packages on the market. The structures were fabricated on 25-mil-thick Al2O3 substrates and the electrical characterization was performed in a test bench integrated with a vector network analyzer HP 8110-C and an in-house-developed cryogenic chamber based on the CTI-Cryogenic closed-cycle unit. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 547–553, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21405

A two‐element interferometer for monitoring atmospheric phase fluctuations (radio seeing) is presented; this uses the unmodulated beacon signal at 11.715 GHz from a geostationary satellite. The system measures phase differences on the signal received by two small antennas separated by 50 m. The system incorporates the best features from previous designs: a heterodyne phase‐lock receiver and an IQ demodulator system. Phase fluctuations measured at this frequency may be extrapolated to millimetric and submillimetric wavelengths since the atmosphere is not dispersive at these frequencies. The instrument has been tested at the Observatory San Pedro Martir (Mexico) at 2800 m above sea level. The final destination of the instrument is Cerro la Negra (Mexico), where the Large Millimeter Telescope is under construction, at an altitude of 4600 m.

A new type of a microwave reflection amplifier with very low noise properties is presented. The proposed amplifier consists of a circulator and a one-port circuit with the use of a transistor operating under negative resistance conditions. An expression for estimating the noise figure for this type of amplifier is proposed. Experimental results show that such a class of amplifiers that use only one transistor provides a higher transmission gain and a smaller noise figure than a conventional single-stage amplifier, making it interesting to operate at millimeter-wave frequencies. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 100–104, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10236

Experimental research on the influence of a transistor amplifier on the noise power value of a passive resistor was performed. An expression for the noise temperature cooling using an attenuator–amplifier circuit is proposed, avoiding physical cooling. A significant deviation of the electromagnetic radiation value from the linear characteristics of a passive resistor is obtained into a given operation bandwidth of the amplifier for relatively small attenuation values and as a function of the input return losses. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 423–427, 2001.

Today, antireflux surgery has an established position in the management of gastroesophageal reflux disease. Some case series have shown good short-term results, but there is still little information regarding long-term results. Studies have recently focused on evaluating residual symptomatology and its impact on quality of life.To determine the postoperative quality of life and degree of satisfaction in patients that underwent laparoscopic Nissen fundoplication.A total of 100 patients (59 women and 41 men) were studied after having undergone laparoscopic Nissen fundoplication. The variables analyzed were level of satisfaction, gastrointestinal quality of life index (GIQLI), residual symptoms, and the Visick scale.No variation was found in relation to sex; 49 men and 51 women participated in the study. The mean age was 49 years. The degree of satisfaction encountered was: satisfactory in 81 patients, moderate in 3, and bad in 2 patients. More than 90% of the patients would undergo the surgery again or recommend it. The Carlsson score showed improvement at the end of the study (p0.05). In relation to the GIQLI, a median of 100.61 points±21.624 was obtained. Abdominal bloating, regurgitation, and early satiety were the most frequent residual symptoms. The effect on lifestyle measured by the Visick scale was excellent.The level of satisfaction and quality of life obtained were comparable with reported standards; and the residual symptoms after antireflux surgery were easily controlled.

Spindle/smooth muscle cell proliferation is an additional neoplastic process related to immunosuppression and EBV infection. We describe four post transplant children with this diagnosis. Multiple organ systems may be involved, particularly the liver, gastrointestinal tract, and lungs. Lesions are radiographically, clinically, and endoscopically indistinguishable from those of post-transplant lymphoproliferative disease (PTLD).

Large-scale receiver operating characteristic (ROC) studies are expensive and time-consuming. If most of the difference in diagnostic accuracy occurs in a subset of subtle cases, considerable effort could be saved by restricting comparisons to this subset. We investigate the effect of subtle cases on diagnostic accuracy, the magnitude of error that can occur because of an imbalance of subtle cases in two groups, and the potential for sample size reductions if only subtle cases are used.Data from a previous study of posteroanterior chest radiographs were reanalyzed separately for subsets of typical cases and subsets of subtle cases. Actually positive and actually negative cases were classified as subtle or typical and as difficult or easy for diagnosis of the specific abnormality. The area under the ROC curve (Az) was used as the measure of diagnostic accuracy. Pairwise comparisons were done among three techniques and for the detection of nodules and interstitial disease.The performance index (Az) was significantly (or = 25%) lower for the subset of subtle cases as compared with the subset of typical cases. The difference in observer performance between two techniques was more often greater in the subset of subtle cases than in the subset of typical cases.The difference in diagnostic accuracy between the subset of typical cases and the subset of subtle cases is large enough that a difference in the proportion of subtle cases in two samples could result in clinically significant false differences in observer performance. Furthermore, the generally larger difference observed in the group of subtle cases suggests that sample sizes for some experiments could be reduced by 45-90% if the experiment were restricted to subtle cases.

Structures having symmetrically centered microstrip lines enclosed in a metallic waveguide are analyzed by the finite-element method. Single and combined shielding effects on the microstrip effective dielectric constant due to a top cover and two side walls are investigated. A finite-element computer program has been written in Fortran for a supercomputer to obtain very accurate numerical results by means of the solution of a very large system of linear equations. In addition, a new set of accurate empirical equations adequate for CAD to take both effects into account has been developed. Results are compared with other numerical and empirical methods, and discussions are also presented. © 1994 John Wiley & Sons, Inc.

Combination antiretroviral therapy (cART) is associated with lipodystrophy (lipoatrophy and lipoaccumulation) and several metabolic abnormalities that together can contribute to an increased cardiovascular risk. The aim of this study was to evaluate the prevalence of obesity in patients on cART according to the presence of clinical lipodystrophy (CL) and to analyze factors associated with obesity.We evaluated 368 HIV-infected adults on cART.CL was present in 59.0%. Independently of gender, patients with CL were more frequently underweight [5.7% (21/368)] and of normal weight [47.3% (174/368)], and less frequently overweight [33.2% (122/368)] or obese [13.9% (51/368)]. Mean body mass index was higher in patients with abdominal prominence regardless of the presence of clinical lipoatrophy. Patients with CL had lower waist circumference, higher waist/hip and fat mass ratio and lower total and subcutaneous fat, without significant difference in visceral fat but with a higher visceral/subcutaneous fat ratio, as evaluated by CT at abdominal level. CL was significantly less frequent in overweight [odds ratio (OR)=0.21, 95% confidence interval (CI): 0.05-0.92] and obese (OR=0.05, 95%CI: 0.01-0.26) patients, when compared to underweight ones, independent of age, gender, duration of infection, cART regimen, virological suppression, and HIV-infection risk factor.Being overweight or obese is highly prevalent in HIV-infected patients on cART. Patients with CL were more frequently under- or normal weight, and less frequently overweight or obese. Obesity is a condition that should be considered in HIV patients on cART.

HIV-lipodystrophy syndrome is characterized by different patterns of body fat distribution (BFD) which are identified by clinical and body composition (BC) assessment, including bioimpedance analysis (BIA). Our aim was to compare BC in HIV-infected patients on combination antiretroviral therapy (cART) according to 4 distinct phenotypes of BFD (G1-no lipodystrophy, G2-isolated central fat accumulation, G3-lipoatrophy, G4-mixed forms of lipodystrophy) and assessed factors associated with them. Anthropometry and BIA were performed in 344 HIV-1 patients. G2 and G4 phenotype patients had significantly higher fat mass (FM) but no differences were observed in fat-free mass (FFM) and total body water among the 4 phenotypes. Significant negative associations were found between the presence of lipoatrophy and female gender, body mass index (BMI), waist (WC), hip (HC) and thigh circumferences, and total body FM estimated by BIA. After adjustment for gender, cART duration and BMI, G3 had significant lower WC [odds ratio (OR)=0.84; 0.78- 0.90] and HC (OR=0.88; 0.81-0.96) mean. Independently of gender, cART duration and BMI, G2 remained significantly associated with higher WC (OR=1.11; 1.05-1.18) and HC (OR=1.15; 1.07-1.23) mean, and with FM estimated by BIA [FM as %, OR=1.17 (1.09-1.26); and FM as kg, OR=1.15 (1.06- 1.25)]. There was a significant positive association between G4 and female gender (OR=1.66; 1.01-2.75), BMI (OR=1.10; 1.04-1.17) and WC (OR=1.15; 1.09-1.21). The similar FFM along the BFD spectrum describes the actual BC of these patients without sarcopenia. In a clinical setting, BIA is an easy and useful tool to evaluate fat mass and FFM and gives us a picture of BC that was not possible with anthropometry.

The aim of this study is to report a case and review the relevant literature. The patient was a 64-year-old male with a right lumbar mass of 5 × 6 cm, which protruded when abdominal pressure was increased. Surgery revealed a defect of 3 × 2 cm in the transversalis fascia in the superior lumbar triangle; prosthetic material was used in the preperitoneal space. Lumbar hernias are rare defects of the abdominal wall (2% of wall hernias); fewer than 300 cases have been reported in the literature. All lumbar hernias can be corrected with surgical treatment. A tension-free mesh repair is almost always necessary, and gives satisfactory results.

The use of open tension-free techniques in hernia surgery seems to be superior to those techniques that apply tension to the suture line. However, the cost-effectiveness of tension vs. tension-free repairs has not been investigated before. This study is a cost-effectiveness analysis within a randomized controlled clinical trial that compared open-tension (OT) versus mesh-plug tension-free (MPTF) hernia repair, with a 2-year follow-up for each patient. Between July 2002 and June 2003, 106 patients with inguinal hernia were randomized to either procedure. Main outcome measures included average surgical time, time to full recovery, pain visual analog scale, amount of analgesics required, off-work time, hospital stay, and heath-care costs. The average cost was $885.15 (95% CI $843.56–$926.74) and $837.66 (95% CI $796.42–878.89) USD for the OT and the MPTF herniorrhaphy, respectively (P

COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only. In this work, it is described the Imaging Magnetograph eXperiment, IMaX, one of the three postfocal instruments of the Sunrise mission. The Sunrise project consists on a stratospheric balloon with a 1 m aperture telescope, which will fly from the Antarctica within the NASA Long Duration Balloon Program. IMaX will provide vector magnetograms of the solar surface with a spatial resolution of 70 m. This data is relevant for understanding how the magnetic fields emerge in the solar surface, how they couple the photospheric base with the million degrees of temperature of the solar corona and which are the processes that are responsible of the generation of such an immense temperatures. To meet this goal IMaX should work as a high sensitivity polarimeter, high resolution spectrometer and a near diffraction limited imager. Liquid Crystal Variable Retarders will be used as polarization modulators taking advantage of the optical retardation induced by application of low electric fields and avoiding mechanical mechanisms. Therefore, the interest of these devices for aerospace applications is envisaged. The spectral resolution required will be achieved by using a LiNbO3 Fabry-Perot etalon in double pass configuration as spectral filter before the two CCDs detectors. As well phase-diversity techniques will be implemented in order to improve the image quality. Nowadays, IMaX project is in the detailed design phase before fabrication, integration, assembly and verification. This paper briefly describes the current status of the instrument and the technical solutions developed to fulfil the scientific requirements. Peerreview

Craniopharyngiomas are rare brain tumors of the hypothalamo-pituitary region, developing from embryonic remnants of Rathke's pouch and sac. Their overall incidence is 0.13 per 100,000 person years. Most frequently, they are suprasellar, start growing in childhood and originate neurological and hormonal symptoms. We retrospectively studied patients treated in our institution for craniopharyngioma in the last 10 years, in order to evaluate their clinical, imaging and pathological characteristics. Of the 32 patients analysed, 18 were females and 14 males with ages ranging between 6 and 81 years (early onset group--EOG aged 5-14 years: 7 patients; middle age onset group--MAOG aged 15-49 years: 15 patients; late age onset group--LOG agedor = 50 years: 10 patients). Visual impairment was the most frequent presenting clinical feature in EOG (71.4%) and MAOG (86.6%), while in the LOG personality and cognitive changes including memory loss predominated (60%). Headaches were very frequent in all groups (EOG 42.8%, MAOG 60%, LOG 40%). Meningitis and seizures were presenting features, each in one patient. Regarding endocrine symptoms and signs, growth failure was present in 57.2% of the EOG. Amenorrhea was present in 5 of 10 female patients of the MAOG. Preoperatively, TSH was deficient in 25%, ACTH in 15.6% and gonadotropin in 25% of the patients. There were no cases of diabetes insipidus. Preoperative CT and MR revealed a calcified mass in 12 (37.5%), a partially cystic mass in 20 (62.5%) and a lesion involving or extending into the third ventricle in 7 (21.9%) patients. Twenty seven (84.4%) patients were treated primarily by surgery. In 4 (12.5%) cases the tumour was considered inoperable and 1 (3.1%) patient refused surgery; all were in the LOG. Surgical approach was transsphenoidal in 2/27 (7.4%) (all of them in the LAOG) and by craniotomy in the others. The tumour removable was considered complete in 10 (37%--EOG 2/7, MAOG 6/15, LOG 2/5) and subtotal in 17 (62.9%) patients. Eight (29.6%) patients were reoperated for recurrent tumour. Postoperative radiotherapy was administered in 12 cases with residual tumor, and 3 inoperable tumors were treated primarily by conventional external radiotherapy. Pathological study revealed the adamantinomatous type in 25 (92.6%) and the papillary type in 2 (7.4%--all men in the MAOG) tumors. The average follow-up was longer in the EOG (82.6 +/- 40.7 months) than in MAOG (57.2 +/- 48.5 months) and in LOG (48 +/- 92 months). Four (12.5%) patients died, 1 during the follow-up period due to a radiation-induced astrocytoma and 3 in the postoperative period because of cerebral hemorrhage and hydrocephalus (1 in the EOG and 2 in the LOG). In summary, we found the clinical presentation to be different in the 3 age groups, with a large number of patients in the MAOG. In this group were the only examples of the papillary form. Better prognosis was associated with a total resection at initial surgery.

Enrique Pacheco, Roberto Conte, Francisco J. Mendieta, Ramon Muraoka, Jose Luis Medina, Arturo Arvizu CICESE Research Center US mail address: PO BOX 434944 San Diego, CA 92143-4944 Km. 107 Carretera Tijuana-Ensenada, Ensenada, B.C. Mexico 22860 Tel. +52 646 175 0554 Fax.+52 646 175 0555 epacheco@cicese.mx, conte@cicese.mx, jmendiet@cicese.mx, rmuraoka@cicese.mx, jmedina@cicese.mx, arvizu@cicese.mx

13 pages, 8 figures.-- Published in: "Optical, Infrared, and Millimeter Space Telescopes" [Section: Solar], edited by John C. Mather.-- Contributed to the conference with same title, Glasgow, Jun 21, 2004., Final full-text version available Open Access at: http://www.iaa.es/~jti/publications/SPIE2Valentin.pdf, The SUNRISE balloon project is a high-resolution mission to study solar magnetic fields able to resolve the critical scale of 100 km in the solar photosphere, or about one photon mean free path. The Imaging Magnetograph eXperiment (IMaX) is one of the three instruments that will fly in the balloon and will receive light from the 1m aperture telescope of the mission. IMaX should take advantage of the 15 days of uninterrupted solar observations and the exceptional resolution to help clarifying our understanding of thesmall-scale magnetic concentrations that pervade the solar surface. For this, IMaX should act as a diffraction limited imager able to carry out spectroscopic analysis with resolutions in the 50.000-100.000 range and capable to perform polarization measurements. The solutions adopted by the project to achieve all these three demanding goals are explained in this article. They include the use of Liquid Crystal Variable Retarders for the polarization modulation, oneLiNbO3 etalon in double pass and two modern CCD detectors that allow for the application of phase diversity techniques by slightly changing the focus of one of the CCDs., This project is funded by the Spanish Programa Nacional del Espacio under project ESP2003-07735.

A telemetry and command subsystem developed in Mexico is presented. The goal of this project is the design, construction, implementation and testing of a RF subsystem to be used on a digital communication link at 148 MHz (VHF band, uplink) and 400 MHz (UHF band, downlink), for the SATEX I microsatellite. The whole system consists of transmitter-receiver equipment for the satellite and its counterpart equipment for the master Earth station. The system also includes a minimal computation subsystem, which acts as a backup in case both the main and redundant onboard computers fail, generating a survival communications mode. Both terrestrial and space segments have an active (hot standby) 2:1 redundancy. A description of the developed prototype and its details are presented.

Distal symmetrical polyneuropathy in diabetics (DPN) has a variable prevalence around 30% and increases the risk for foot ulcers and amputations. We aimed at evaluating the prevalence of clinical DPN and associated risk factors in patients followed in primary care centers.101 type 2 diabetics were evaluated and 8 were excluded due to the presence of other causes of neuropathy. The remaining 93 had a mean age of 65.4 +/- 10.1 years and a mean diabetes duration of 10.1 +/- 11.1 years, 60.2% were women and 39.8% men. DPN was defined as the presence of both altered sensitivities and reflexes, regardless of symptoms.Seventy-two (80%) patients had symptoms of polyneuropathy, but DPN was present only in 29 (32.2%). Calluses (37.8%) and trophic skin (74.4%) and nail (75.6%) changes were found in both feet. There was a significant positive association of DPN with age (69.0 +/- 9.1 vs 63.3 +/- 9.9 years, p=0.01), disease duration (15.7 +/- 13.5 vs 7.2 +/- 8.8 years, p=0.001), feet skin changes (38.8 vs 13.0%, p=0.04) and myocardial infarction/ischemia (14.8 vs 1.7%, p=0.03).This sample of diabetic patients cared by family doctors presented a high prevalence of DPN. Aging, disease duration, the presence of feet skin changes and myocardial infarction/ischemia are factors that increase the prevalence of the disease. Primary care doctors awareness of the problem might help to decrease the associated morbidity.

Congenital generalized lipodystrophy, or Berardinelli-Seip syndrome (BSCL), is a rare autosomal recessive disease characterized by a near-absence of adipose tissue from birth or early infancy and severe insulin resistance. Other clinical and biological features include acanthosis nigricans, hyperandrogenism, muscular hypertrophy, hepatomegaly, altered glucose tolerance or diabetes mellitus, and hypertriglyceridemia. A locus (BSCL1) has been mapped to 9q34 with evidence of heterogeneity. Here, we report a genome screen of nine BSCL families from two geographical clusters (in Lebanon and Norway). We identified a new disease locus, designated BSCL2, within the 2.5-Mb interval flanked by markers D11S4076 and D11S480 on chromosome 11q13. Analysis of 20 additional families of various ethnic origins led to the identification of 11 families in which the disease cosegregates with the 11q13 locus; the remaining families provide confirmation of linkage to 9q34. Sequence analysis of genes located in the 11q13 interval disclosed mutations in a gene homologous to the murine guanine nucleotide-binding protein (G protein), gamma3-linked gene (Gng3lg) in all BSCL2-linked families. BSCL2 is most highly expressed in brain and testis and encodes a protein (which we have called seipin) of unknown function. Most of the variants are null mutations and probably result in a severe disruption of the protein. These findings are of general importance for understanding the molecular mechanisms underlying regulation of body fat distribution and insulin resistance.

Quality assurance is a relatively recent concern but already plays a major role in health care management and provision. Quality involves the definition of a comprehensive programme tailored by realistic and effective objectives and norms that include the structured review of procedures (namely clinical audits) and the use of up-to-date protocols. The involvement and motivation of health professionals, together with an adequate internal and external communication strategy, play a key role in the planning and application of these programmes. The use of programmed assessment, based on a solid knowledge of current practice, should have practical implications, optimising procedures in order to improve the quality of care. This commitment towards quality in health care should go far beyond governmental policy and should have clear support from health professionals.

The Bronchogenic Carcinoma Cooperative Group of the Spanish Society of Pneumology and Thoracic Surgery (GCCB-S) has been enrolled in a prospective data collection project from patients with bronchogenic carcinoma who underwent thoracotomy in 20 Spanish hospitals from October 1993 to September 1997. In this 4-year period, 2995 patients were registered and demographic, clinical, biological, diagnostic, surgical, pathological and follow-up information collected in a homogeneous way. The main objectives of the Group are to describe the population with lung cancer at the time of diagnosis in Spain; to analyse operative morbi-mortality; and to identify multiple prognostic factors. So far, some preliminary results have already been published concerning the description of the population, the methodology of the Group, the assessment of morbi-mortality, and the validation of the 1997 TNM classification.

The noninvasive preoperative assessment of lung cancer is currently based on CT scan. This technique is used to find out the local extension of the tumor and to identify the presence of mediastinal adenopathies by distinguishing as accurate as possible between benign and metastatic adenopathies according to their size. When CT scan suggests the presence of suspected mediastinal lymph nodes, invasive diagnostic methods are indicated to confirm whether the lymph nodes are affected (transbronchial needle aspiration, mediastinoscopy, mediastinotomy and thoracoscopy). Transesophageal echography (TEE) was first used in the 80's as a diagnostic guide in the clinical classification of gastrointestinal tumors and may be of help in the mediastinal evaluation of lung cancer as well. Several studies have demonstrated the value of TEE in detecting mediastinal adenopathies and mediastinal structures involvement (great vessels and mediastinal organs) by assessing the direct growth of the primary tumor which is crucial in the surgical decision. To distinguish benign from metastatic nodes TEE, unlike CT scan, does not consider their size only but other issues as shape, definition of edges and echographic structure. Generally speaking, TEE detects more adenopathies than CT scan but not in all mediastinal stations since it is limited by the presence of air; thus, adenopathies located in the upper mediastinum, mainly on the right side, are usually missed by TEE. The areas more clearly visualized are the subcarinal, paraesophageal, tracheobronchial and hilar ones and mainly those located in the aortopulmonary window. Currently, TEE can be used also to guide a thin needle toward the lymph nodes and to perform its aspiration biopsy. In conclusion, transesophageal and/or endobronchial echography are developing promising diagnostic methods which provide additional information that can influence the clinical decision making process and the prognosis. They are well tolerated by the patients but time is needed to find out their role. Lastly, their usefulness will depend also on their feasibility since an expensive equipment and specifically well trained staff are needed.

The authors review some etiological, clinical and diagnostic aspects of nephrolithiasis, describing briefly the approach that should be taken to study this disease. Some of the practical aspects of its treatment are also discussed.

[ES] La estimación de la evapotranspiración es esencial en los sistemas de riego, en el cálculo de pérdidas de agua en embalses, en la estimación de balances hídricos, en las predicciones de escorrentía, así como en estudios climatológicos y meteorológicos. Las nuevas técnicas denominadas teledetección y sistemas de información geográfica (SIG) permiten el cálculo de la distribución espacial de este parámetro. Un nuevo modelo racional, SEBAL (Bastiaanssen, 1995), basado en la ecuación de conservación de la energía, ha sido aplicado en el estudio que se presenta. En este modelo se ha reducido el número de relaciones empíricas, además de presentar otras ventajas. El modelo ha sido calibrado y validado en una zona localizada en el Valle del Guadalquivir (España), a partir de una imagen del satélite Landsat-TM5 y de información climática. Posteriormente, el modelo ha sido utilizado con una resolución menor que la original por medio de un procedimiento de agregación de la imagen TM original. Este cambio en la resolución fue adoptado al objeto de comprobar la posible utilización de otras clases de imagen de satélite (por ejemplo, el NOAA). La evapotranspiración y otras variables obtenidas por teledetección se relacionan con ciertas características superficiales, por medio del uso de mapas de cultivos, suelos y mapas digitales de elevación del área de estudio., Se agradece a M. Menenti y W.G.M. Bastiaanssen del Department of Water Management in Arid Zones (DLO-Winand Staring Centre, Wageningen. The Netherlands) y sus colaboradores, todos los comentarios y material proporcionado para determinar la ET usando imágenes Landsat.

Recently, disconnect systems for CAPD that are associated with a reduced frequency of peritonitis have been introduced. Our objective was to compare the incidence of peritonitis using three current CAPD systems in a high-risk population with low educational and socioeconomic levels, and high prevalence of malnutrition.In a prospective controlled trial, 147 patients commencing CAPD were randomly assigned to one of three groups: 29 to the conventional, 57 to the Y-set, and 61 to the twin bag systems. The number of peritonitis episodes was registered, and patients were followed up for an average of 11.3 months.The average peritonitis-free interval for the conventional group was 6.1 months, for the Y system was 12.0 months, and for the twin bag was 24.8 months (P0.001). By multivariate analysis, the only factor associated with peritonitis was the CAPD system. Peritonitis-related hospitalization was 5.3 +/- 2.0, 2.7 +/- 1.0, and 1.5 +/- 0.9 days/patient/year in the conventional, Y system, and twin bag groups, respectively. The cost per bag was similar for the conventional and Y system, but higher for the twin bag. However, the total costs of treatment (pesos/patient/year) were lower for twin bag (62,159 for the conventional, 70,275 for the Y system, and 54,387 for the twin bag), due to the lower peritonitis incidence and associated hospitalizations.Y system and twin bag use was associated with a reduction of 50 and 75% peritonitis incidence, respectively, in patients on CAPD. The cost of the twin bag was actually lower, because of savings from a decreased usage of antibiotics and fewer hospitalizations.

After analyzing the prior questions which determine the nursing field contents, the authors propose "reflective practice" as the methodological and pedagogical philosophy of choice in the formation of nurses. According to the authors, the professor is responsible for developing the curriculum. As such, the professor makes decisions regarding course design, methodology, content development, and student evaluation in terms of aptitute, attitude and knowledge acquisition. Research studies seem to demonstrate that the knowledge which, in the end, aids in comprehending the context taught and which determines the decisions a professor takes, is that knowledge based on a reflective practice, a product of the professor's experiences, background, knowledge and active relationship with nursing practice. The contents in this article were presented as a conference in the Third Seminar of Professors of Nursing for General Practice and Surgery.

Spindle/smooth muscle cell proliferation is an additional neoplastic process related to immunosuppression and EBV infection. We describe four post transplant children with this diagnosis. Multiple organ systems may be involved, particularly the liver, gastrointestinal tract, and lungs. Lesions are radiographically, clinically, and endoscopically indistinguishable from those of post-transplant lymphoproliferative disease (PTLD).

Generalised lipodystrophy of the Berardinelli-Seip type (BSCL) is a rare autosomal recessive human disorder with severe adverse metabolic consequences. A gene on chromosome 9 (BSCL1) has recently been identified, predominantly in African-American families. More recently, mutations in a previously undescribed gene of unknown function (BSCL2) on chromosome 11, termed seipin, have been found to be responsible for this disorder in a number of European and Middle Eastern families. We have studied the genotype/phenotype relationships in 70 affected subjects from 44 apparently unrelated pedigrees of diverse ethnic origin. In all subjects, hepatic dysfunction, hyperlipidaemia, diabetes mellitus, and hypertrophic cardiomyopathy were significant contributors to morbidity with no clear differences in their prevalence between subjects with BSCL1 or BSCL2 and those with evidence against cosegregation with either chromosome 9 or 11 (designated BSCLX). BSCL2 appears to be a more severe disorder than BSCL1 with a higher incidence of premature death and a lower prevalence of partial and/or delayed onset of lipodystrophy. Notably, subjects with BSCL2 had a significantly higher prevalence of intellectual impairment than those with BSCL1 or BSCLX (p