Search

The first non-coastal Sub-Antarctic Marine Protected Area (Namuncura) in Argentina was created in 2013, at Burdwood Bank (MPAN-BB), an undersea plateau located about 200 km south from Malvinas/Falkland Islands, SW Atlantic Ocean. The main contribution of this work was to explore fish species composition and the structure of fish assemblages in three different zones of the MPAN-BB with different conservation strategies and different surrounding areas. Twenty-two fishing trawls were performed using a demersal bottom trawl pilot net at depths between 71 and 608 m. A total of 667 fish belonging to 30 species were collected in the surveyed area. The richest family in terms of species number was Nototheniidae (seven species), followed by Macrouridae, Myxinidae and Zoarcidae (four species each), then Moridae and Arhynchobatidae (three species each), and finally Muraenolepididae and Psychrolutidae (two species each). The remaining families were represented by a single species. Three significantly different fish assemblages were detected. These distinct assemblages were largely circumscribed at the plateau, the shelf-break slope, and the area west of the BB. The results showed that fish diversity in the MPAN-BB is relatively high constituting ~ 10% of the fish composition reported for the Atlantic sector of the Magellanic Province. The present data suggest that fishes are an important component of the benthic community planned to be protected by the implementation of the MPAN-BB. These findings have important implications for habitat preservation and threatened species conservation.

We conducted a revision of the Neotropical genus Acrobrycon. A previous study synonymized the species, A. ipanquianus, distributed from the western portion of the Amazon River to the north-western region of the La Plata River Basin, and A. tarijae, with type locality in the Lipeo River in Bolivia. We revisited this result by collecting new morphometric, meristic, and genetic data (COI mitochondrial gene) for 24 individuals distributed along La Plata River Basin in Argentina, and discussed our results in the context of multiple biogeographic processes of isolation in that basin. Our results revealed a more complex history of diversification and geographic distribution across Acrobrycon species than previously suspected, probably associated with multiple biogeographic processes of isolation in La Plata River Basin. We present new evidence that led us to reconsider the validity of A. tarijae, which is distinguishable from A. ipanquianus by the number of vertebrae (37–39 vs. 41–42) and pleural ribs (12–13 vs. 14). These results were also supported by our molecular analyses that revealed a genetic divergence >4% between A. ipanquianus and A. tarijae. We also identified two main genetic clusters within A. tarijae: the first cluster consisted of specimens from the Bermejo, Pilcomayo, Itiyuro and Juramento river basins (northern Argentina); and the second cluster included specimens from the southernmost basins, such as the Salí River in Tucumán, Cuarto River in the province of Cordoba and the Quinto River in the province of San Luis. Our results suggest that the genetic structure observed in A. tarijae is the result of the type of drainage (endorheic vs. exorheic) and geographical distance.

A new species belonging to the Hoplias malabaricus complex from the Amazon basin, Brazil, is described. The new species is characterized by 15-16 predorsal scales, 37-39 lateral-line scales, 5 scales from dorsal fin to lateral line, 38-39 vertebrae, iii-iv, 7-8 anal-fin rays, ii-iv, 12-15 caudal-fin rays, last vertical series of scales on the base of caudal-fin rays forming a straight line, 6-7 dark bands in anal fin and no distinctive dark bands or blotches on flanks. The new species is also distinguished from other congeners of the H. malabaricus species-group by means of landmark-based morphometrics and DNA Barcoding (Cytochrome c Oxidase I gene). An identification key to species of the H. malabaricus species complex is provided.

We conducted a revision of the Neotropical genus

The mechanisms that drive nonalcoholic fatty liver disease (NAFLD) remain incompletely understood. This large multicenter study characterized the transcriptional changes that occur in liver tissue across the NAFLD spectrum as disease progresses to cirrhosis to identify potential circulating markers. We performed high-throughput RNA sequencing on a discovery cohort comprising histologically characterized NAFLD samples from 206 patients. Unsupervised clustering stratified NAFLD on the basis of disease activity and fibrosis stage with differences in age, aspartate aminotransferase (AST), type 2 diabetes mellitus, and carriage of PNPLA3 rs738409, a genetic variant associated with NAFLD. Relative to early disease, we consistently identified 25 differentially expressed genes as fibrosing steatohepatitis progressed through stages F2 to F4. This 25-gene signature was independently validated by logistic modeling in a separate replication cohort (n = 175), and an integrative analysis with publicly available single-cell RNA sequencing data elucidated the likely relative contribution of specific intrahepatic cell populations. Translating these findings to the protein level, SomaScan analysis in more than 300 NAFLD serum samples confirmed that circulating concentrations of proteins AKR1B10 and GDF15 were strongly associated with disease activity and fibrosis stage. Supporting the biological plausibility of these data, in vitro functional studies determined that endoplasmic reticulum stress up-regulated expression of AKR1B10, GDF15, and PDGFA, whereas GDF15 supplementation tempered the inflammatory response in macrophages upon lipid loading and lipopolysaccharide stimulation. This study provides insights into the pathophysiology of progressive fibrosing steatohepatitis, and proof of principle that transcriptomic changes represent potentially tractable and clinically relevant markers of disease progression. Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works

Local habitat and riparian modifications imposed by surrounding land use drastically impact the water quality of streams. However, whether these effects could still be discernible when the watercourse also receives urbanization effluents has not been fully explored. We evaluated the water quality of a Neotropical prairie stream exposed to urbanization and explored the role of downstream patches of different surrounding land uses (cropland and livestock) in further regulating water quality. Forty-two variables of water quality, habitat structure and riparian condition were measured at four reaches of the Langueyú stream. Significant differences in water quality were observed. Water conductivity, dissolved oxygen, salinity, dissolved solids, chloride, inorganic nitrogen and bacteriological loads displayed a continuum of recovery from the urban reach. Indeed, almost 24 percent of the total variation in water quality was explained by the longitudinal arrangement of sites. Alternatively, pH, phosphorous, suspended solids and chemical oxygen demand showed a disruption in this continuum of recovery and were highly related with local aspects of habitat structure and riparian conditions imposed by cropland and livestock. Key aspects of effluent treatment, riparian integrity and in-stream habitat must be addressed within a comprehensive social context in order to design sustainable management of fluvial urbanised ecosystems.

BACKGROUND Minimally Invasive Muscle Embedding (MIME), is a technique developed in our laboratory, to facilitate the development of donor-cell-derived muscle fibers in a host muscle. MIME involves ...

Malignant tumors of ectodermal or endodermal origin may metastasize to the sentinel lymph node, the first lymph node encountered by tumor cells that enter lymphatics in the organ of origin. This pathway is enabled by the anatomy of the disease and the causes of metastasis are the result of complex interactions that include mechanical forces within the tumor and host tissues, and molecular factors initiated by tumor cell proliferation, elaboration of cytokines and changes in the tumor microenvironment. Mechanical stresses may influence complex biochemical, genetic and other molecular events and enhance the likelihood of metastasis. This paper summarizes our understanding of interacting molecular, anatomical and mechanical processes which facilitate metastasis to SLNs. Our understanding of these interacting events is based on a combination of clinical and basic science research, in vitro and in vivo, including studies in lymphatic embryology, anatomy, micro-anatomy, pathology, physiology, molecular biology and mechanobiology. The presence of metastatic tumor in the SLN is now more accurately identifiable and, based upon prospective clinical trials, paradigm-changing SLN biopsy has become the standard of clinical practice in breast cancer and melanoma.

PURPOSE Laparoscopic intragastric resection is a surgical modality with acceptable oncologic outcomes for gastrointestinal stromal tumors and leiomyomas, particularly for masses located near the gastroesophageal junction (GEJ). We describe our technique of 2 gastrostomy laparoscopic, intragastric resection with endoscopic assistance. METHODS We detail our technique and report a unique application of this versatile approach. RESULTS Between December 2015 and July 2016, 4 patients underwent our combined technique of intragastric surgery. Complete resection was performed in the 2 patients who had gastrointestinal stromal tumors and 1 patient with a leiomyoma without complications. One patient had the unique diagnosis of gastritis cystica profunda. This mass could not be resected, but an effective Tru-cut core needle biopsy was obtained, and the mass was able to be diagnosed and decompressed. CONCLUSIONS Our technique of 2 gastrostomy laparoscopic intragastric surgery is feasible and offers an effective oncologic approach for resection of tumors near the GEJ.

Lymph node metastases (LNMets) are common problems for patients and those involved in their management. Patients with LNMets from various cancers are often at a higher risk for death from cancer than those whose lymph nodes (LNs) are free of cancer. Clinical and pathologic staging of cancer is dependent upon identification of LNMets. Understanding how tumor cells migrate to LNs is still evolving. The relationship among LNMets and systemic metastases are vigorously debated; those who believe that LNMets merely identify those tumors that have probably already metastasized systemically (“marker” hypothesis) and those who believe that systemic metastases are derived from passage through regional LNs and only very rarely by direct blood vessel invasion (“incubator” hypothesis). Diagnosis and treatment of LNMets has advanced significantly over the past century and it seems likely that further improvements will develop. This chapter is a brief introduction into the present understanding of LNMets.

The reaction chemistry and kinetics of the low temperature hydroformylation of the water-soluble substrates, 4-penten-1-ol and 3-buten-1-ol, in aqueous solution utilizing the catalyst HRh(CO)(TPPTS)3 is reported where, TPPTS is trisulphonated triphenylphosphine. The reactions were carried out at relatively low temperature and high stirring rates (1700 rpm) to maintain similar rates of mass transfer of gases into the aqueous phase. Activation parameters and reaction selectivity for the hydroformylation of 4-penten-1-ol are found to be dependent on solution ionic strength. At [Rh]=5×10−4 M, an activation energy for the hydroformylation of 4-penten-1-ol of 23 kcal mol−1 is estimated. As sodium sulfate is added to the catalytic phase the activation energy increases. The dependence of reaction selectivity on ionic strength is unexpected. The reaction can be directed to yield a product distribution of modest linearity (75%) or an exceptionally high ratio of the branched product, observed exclusively as a cyclic 2-hydroxy-3-methyltetrahydropyran (98%), by control of solution ionic strength and temperature. A wider range of selectivities can be obtained for 4-penten-1-ol in water with HRh(CO)(TPPTS)3 than can be obtained in toluene with HRh(CO)(PPh3)3. The hydroformylation of 3-buten-1-ol is less sensitive to reaction conditions. An activation energy of 25 kcal mol−1 is estimated at [Rh]=2.5×10−4 M. Reaction selectivity favors in this case the formation of a six-membered over a five-membered cyclic acetal and is not influenced by temperature or solution ionic strength. It appears that the hydroxy group can direct the site of CO addition to alkenols, perhaps by chelate formation, and that solution ionic strength affects its ability to do so.

The biphasic hydrogenations of a number of polymeric materials, polybutadiene (PBD), nitrile-butadiene rubber (NBR) and styrene-butadiene rubber (SBR), were investigated in a toluene/N,N′-butylmethylimidazolium tetrafluoroborate, (BMI+BF4−) system with a water-soluble analogue of Wilkinson's catalyst, RhCl(TPPTS)3 (TPPTS=triphenylphosphine, trisulfonated) at 100 °C and 3.1 MPa. The catalyst shows reasonable activity within ionic liquids with PBD although it was necessary in the case of NBR and SBR to add water as a co-solvent to solubilize the catalyst within the ionic media. Both the extent of hydrogenation and the ratio of the internal 1,4-olefins to vinyl 1,2-olefins were monitored. A clear preference for the external olefins was observed even within NBR and SBR where functionalization on the polymer might enhance the degree of hydrogenation of the internal olefins. The effect of adding NaCl to the PBD system was also investigated. The addition of salt decreases the activity of the catalyst but has no effect on the preference for the hydrogenation of vinyl olefins.

Background and aims A significant decrease of left ventricular ejection fraction (LVEF) at stress has been reported with 99Tc(m) gated single-photon emission computed tomography (gSPECT) in severe myocardial stunning up to 1 h after exercise. This study was designed to show whether 201Tl gSPECT can measure LVEF evolution from rest to stress in routine examination and give additional information to perfusion interpretation since acquisition starts immediately after stress test. Methods Post-exercise and rest 201Tl gSPECT were performed in 187 patients with suspected coronary artery disease. Myocardial perfusion was quantified by 20-segment analysis. Patients were divided into four groups according to their summed perfusion score, reversibility rate and electrocardiographic findings, i.e. in order of severity: I = normal perfusion, II = fixed defect owing to a myocardial infarction, III = full reversible ischaemia, and IV = partial reversible ischaemia. LVEF was calculated by Germano's automatic algorithm. Results Normal subjects (n = 29) and infarcted patients (n = 34) showed a significant LVEF increase between rest and stress, +7 +/- 9% and +5 +/- 7% respectively. In full reversible ischaemic patients (n = 46), stress LVEF showed no increase (+1 +/- 8%) and this group was statistically different from both group I and group II. Furthermore, when ischaemia was partially reversible (n = 31), LVEF decreased significantly (-3 +/- 8%), particularly when exercise tests were abnormal (-4 +/- 8%). Group IV was statistically different from groups I and II. Conclusions Good agreement exists between the severity of ischaemic perfusion pattern and LVEF degradation at stress, which is consistent with previously published data using 99Tc(m) gSPECT. Additionally, the use of 201Tl for immediate post-exercise imaging allows the observation of a physiological LVEF increase in normal and infarcted patients.

Breast cancer is the most common cancer affecting women worldwide. Prediction models stratify a woman's risk for developing cancer and can guide screening recommendations based on the presence of known and quantifiable hormonal, environmental, personal, or genetic risk factors. Mammography remains the mainstay breast cancer screening and detection but magnetic resonance imaging and ultrasound have become useful diagnostic adjuncts in select patient populations. The management of breast cancer has seen much refinement with increased specialization and collaboration with multidisciplinary teams that include surgeons, oncologists, radiation oncologists, nurses, geneticist, reconstructive surgeons and patients. Evidence supports a less invasive surgical approach to the staging and management of the axilla in select patients. In the era of patient/tumor specific management, the advent of molecular and genomic profiling is a paradigm shift in the treatment of a biologically heterogenous disease.

The rates of dissolution of olivine (Fo92) were measured over the pH range of 1.8 to 3.8 and from 25 to 45°C using an externally recycled mixed flow reactor. The data were filtered to remove several sources of systematic errors including non-steady state measurements, solution concentrations that were less than 50% above the detection limit, and Mg/Si rate ratios 40% (∼3σ or 98% confidence limit) greater or smaller than 1.84, which is the stoichiometric ratio of these elements in the mineral used. The effect of random errors on calculated values of Ea and n were minimized by collecting a large amount of data. Twenty-eight different runs produced 772 rate measurements of which 284 were rejected in order to remove systematic and large random errors, leaving 488 data. The errors associated with these remaining data are normally distributed. The data were regressed to the equation log r- log A− E a 2.303R 1 T −n pH to find that log A = 0.54 ± 0.14, Ea = 42.6 ± 0.8 kJ/mol, and n = 0.50 ± 0.004 (R2 = 0.97). Based on these results, we postulate that the activated complex for forsterite dissolution involves a hydronium ion adsorbed to the forsterite surface in such a way that two of the three hydrogen atoms are associated with two Si-O-Mg bridging oxygen atoms. In this configuration, the adsorbed hydronium ion dissociates to form H-O-Si bonds as water molecules move from the solution to hydrate the two Mg atoms, breaking the Mg-O-Si bonds. This dissociation of the hydronium ion to form two H-O-Si groups on the forsterite surface leads to the observed reaction order for hydrogen ions of 0.5. The rate of breakdown of this activated complex is proportional to the rate at which the water molecules move from the solution to hydrate the Mg ions. Several other silicate mineral dissolution reactions, which have reaction orders of 0.5, may involve similar activated complexes.

XPS analyses of naturally formed iron and manganese oxide surfaces reveals important information used for interpreting mineral surface reactivity in our environment. Specifically, these oxides and oxyhydroxides give us details about the oxidation state of manganese phases commonly found during heterogeneous reactions. This type of analysis is also useful for interpreting the formation history of natural mineral surfaces. In this submission we present XPS data on the mineral surfaces hematite (α-Fe2O3), goethite (α-FeOOH), pyrolusite (β-MnO2), and manganite (α-MnOOH).

Sentinel lymph node(SLN) biopsy has become the gold standard for patients with melanoma and breast cancer but it's clinical application in other solid tumor types such as cancers of the esophagus, stomach, colon and rectum, head and neck, penis, uterine cervix and endometrium has been somewhat limited. Commonly used mapping techniques utilizing the combination of radiocolloid and blue dye may result in reduced SLN detection and increased false negative rates when applied to cancers with more complex lymphatic drainage patterns. Novel localization techniques includingnear infrared fluorescence, high resolution imaging and molecular targeted agents have been developed to address the limitations of conventional SLN detection practices in many solid tumor types. This article reviews the indications, techniques and detection rates for SLN biopsy in several different solid tumor types as well as the promising novel techniques created to address the contemporary limitations of this procedure.

Bacterial sulphate reduction is the predominant process in the cycling of organic matter and anthropogenic contaminants in permanently anoxic sediments such as those of the Venice canal network. Urban materials delivered to the canals and suspended particles transported by tidal currents from the open lagoon cause the silting up of the channel bed at a rate of 2 cm y-1, therefore requiring periodic dredging. As the recent maintenance interventions on canals are accompanied by the extensive improvement of the sewer system, there is an increasing interest for understanding how effective are natural processes in the metabolism of the large amount of organic matter accumulating in the sediment. A specific investigation on sulphate reduction was then started on May 2003. Sulphate reduction rates were measured, as sulphate depletion on incubated sample of the superficial sediment (0-5 cm), in 5 test canals. Measurements were repeated in July and October 2003, to investigate how the rates vary in response to temperature changes. If compared to typical values for estuary and salt marshes, rates measured are among the highest (up to 1.7 mmol l-1 d-1), the limiting factor being only the concentration of S2-. As expected, the highest rates were measured in summer (0.5-1. 7 mmol l-1 d-1). However, significant spatial differences were observable, particularly in the way each site responds to seasonal changes. We interpret major changes as the effect of a non-uniform distribution of bacterial population within the network sediments or a different diffusion of SO42- as a result of local changes in the aggregation state of the sediment. A simple first-order kinetic model applied to S042- concentrations measured in pore waters from 30 cm-long sediment cores finally permitted to better estimate the mean annual sulphate reduction rates which are consistent with values obtained by the incubation of surface sediments.

The fate of anthropogenic heavy metal in the contaminated anoxic sediments of the Venice canals is mainly conditioned by sulphidic transformations occurring during the early diagenesis. Bacterial sulphate reduction is the key process in the metabolism of organic matter supplied to the system by the untreated effluents directly discharged in the network. Based on our recent measurements of sulphate reduction rates in representative sites, an average of more than 500 kg d-1 of sulphate-S is converted into S 2- in the warm period (May-October). Part of the so formed S2- can diffuse across the sediment water-interface, being eventually released to the water column and readily oxidised. However, a considerable proportion of S2- combines with reactive iron in pore waters forming insoluble sulphides, mainly FeS, which accumulate in the sediment ultimately leading to the formation of FeS2. Anthropogenic heavy metal are generally adsorbed to or coprecipitated in these newly formed phases. However, if metals enter the system as coarse particles, as easily occurs in the Venice canals, a variety of bulk metal-sulphides can form as the result of direct sulphurisation of the original metallic compounds. The partitioning of sulphur compounds in sediments from 5 selected sites of the network was investigated by collecting 35 cm-long cores. Pore water concentration of heavy metals, SO42- and S2- as well as the distribution of solid-phase sulphur (S0, AVS, CRS) and AVS-metals concentrations were considered revealing interesting implications, particularly for As and S2-. The gravity-separation of dried sediment aliquots permitted a detailed investigation on sulphide particles by reflected light optical microscopy, and the study of their microchemistry by scanning electron microscopy combined to energy dispersive x-ray fluorescence. The results show as Cu and Zn sulphides are commonly found in replacement of original compounds and can coexist in intimate association with FeS and FeS2, sometimes forming reaction rims.

Background: Sentinel lymph node (SLN) tumor metastasis size (TMS) and extra-capsular extension (ECE) are predictive of non-SLN metastasis. We hypothesized that SLNTMS and ECE would also be predictive of systemic metastasis and death. Materials and Methods: Data from 2,001 women with breast cancer who underwent SLN biopsy were prospectively collected and retrospectively analyzed. SLNTMS and ECE were measured, reported according to standard pathologic protocols and recorded. Data were analyzed from 252 patients with both SLNTMS and ECE information available. Cancer-specific mortality and all-cause mortality were observed, calculated and multivariable analyses performed to identify significant interacting variables amongst demographics, clinical stage and pathological characteristics. Results: Thirty eight treated patients died from any cause and 12 died of cancer during the 16.4 year follow-up. Patients with ER expression had a significantly lower risk of dying of cancer compared to those who lacked ER expression (HR = 0.198, 95% CI 0.06-0.62; P = 0.006). SLNTMS (P = 0.929 and 0.677) and ECE (P = 0.723 and 0.926) were not significant in the multivariable models of either disease specific or all-cause mortality. Conclusion: Neither SLNTMS nor the presence of ECE affected disease-specific or overall mortality in our breast cancer patients.

We sought to evaluate dobutamine stress echocardiography (DSE) for predicting recovery of viable myocardium after revascularization with cineangiography as a gold standard for left ventricular (LV) function. We studied the influence of late vessel reocclusion on regional LV function.Dobutamine stress echocardiography is a well established evaluation method for myocardial viability assessment. In previous studies the reference method for assessing LV recovery was echocardiography, long-term vessel patency has not been systematically addressed.Sixty-eight patients with a first acute myocardial infarction (AMI) and residual stenosis of the infarct related artery (IRA) underwent DSE (mean +/- standard deviation) 21 +/- 12 days after AMI to evaluate myocardial viability. Revascularization of the IRA was performed in 54 patients by angioplasty (n = 43) or bypass grafting (n = 11). Coronary angiography and LV cineangiography were repeated at four months to assess LV function and IRA patency.Sensitivity and specificity of DSE for predicting myocardial recovery after revascularization were 83% and 82%. In the case of late IRA patency, specificity increased to 95%, whereas sensitivity remained unchanged. In the 16 patients with myocardial viability and late IRA patency, echocardiographic wall motion score index decreased after revascularization from 1.83 +/- 0.15 to 1.36 +/- 0.17 (p = 0.0001), and left ventricular ejection fraction (LVEF) increased from 0.52 +/- 0.06 to 0.57 +/- 0.06 (p = 0.0004), whereas in five patients, reocclusion of the IRA prevented improvement of segmental or global LV function despite initially viable myocardium.Dobutamine stress echocardiography is reliable to predict recovery of viable myocardium after revascularization in postinfarction patients. Late reocclusion of the IRA may prevent LV recovery and influence the accuracy of DSE.

Every RiMG volume is unique and special and, over the years, RiMG volumes have cumulatively covered the atomic to global scales for a variety of topics related to mineralogy and geochemistry. Carbon in Earth continues in this tradition. In Carbon in Earth , the reader will learn about the intricate aspects of atomic mineral crystal structures, models of carbon emissions …

The spectrum of pulmonary disorders associated with HIV infection includes both infectious and noninfectious diseases (table 1) [1,2]. In 1993, Pneumocystis carinii pneumonia (PCP) is still the most common HIV-related pulmonary infection in Europe and in the United States; other opportunistic pathogens are less frequent (although their relative incidence is increasing as the number of patients under PCP prophylaxis has risen and survival has been prolonged) [2]. Usual pathogens are also frequently found, particularly in Africa, and the frequency of tuberculosis is increasing elsewhere [2]. However, it must be kept in mind that the differential diagnosis of a suspected infection still includes several noninfectious complications (table 1) such as symptomatic pulmonary Kaposi sarcoma (KS) [1]. Furthermore, most of the patients have multiple infectious and noninfectious pulmonary complications simultaneously or alternately during the course of their HIV disease [1,2]. Since each pulmonary disorder requires a specific treatment, a definite diagnosis should be made each time a complication occurs and may often need repeated fiberoptic investigations [1,2]. Unfortunately, chest X-ray may be normal, clinical and radiological data are often non-specific and results obtained from pulmonary testing are neither specific nor sensitive in detecting pulmonary disease [1,2]. This emphasizes the need for new noninvasive procedures to limit the number of patients who really require exhaustive pulmonary diagnostic evaluation. In this context, two different radionuclides, gallium-67 citrate and technetium-99m diethylenetriamine pentaacetate (Tc-DTPA), have been used for assessment of the lungs of patients with HIV infection [3–5]. Gallium was used first as a means of detecting whether or not lung disease was present [6–18]. Tc-DTPA was then used, initially for research purposes, to study the permeability characteristics of the lung parenchyma, [19–22] but it has recently been considered more sensitive than gallium to detect PCP in HIV infected patients [23,24].

We retrospectively compared the results of 67Ga chest scans and 99mTc-DTPA aerosol clearance measurements with those of fiberoptic bronchoscopy in 88 patients infected with the human immunodeficiency virus. Of 100 investigations, a pulmonary infection was diagnosed in 39, mainly Pneumocystis carinii pneumonia and a noninfectious disorder was found in 42, mainly Kaposi's sarcoma and lymphocytic alveolitis. Gallium scans and DTPA clearance were abnormal respectively in 74% and 92% of infectious complications, and in 12% and 60% of noninfectious disorders. In 10 cases, DTPA clearance was accelerated, while chest x-ray, arterial blood gases and even gallium scanning were normal. A value of DTPA clearance greater than 4.5%.min-1 was both sensitive and specific for the diagnosis of Pneumocystis carinii pneumonia. The gallium scan was always normal in bronchopulmonary Kaposi's sarcoma. We conclude that in symptomatic patients: (1) DTPA clearance measurements are useful for detecting lung disease when chest x-ray and/or PaO2 are normal and (2) a gallium scan is indicated to distinguish progressive Kaposi's sarcoma from a superimposed second process when radiological abnormalities of pulmonary Kaposi's sarcoma are present.

The fuel cell technology for the advanced portable life support system is reviewed, using the breadboard test data, and the design concepts are presented for the development of the improved preprototype fuel cell. Subscale test results confirm the suitability of the solid polymer electrolyte fuel cell fueled by hydride stored hydrogen and oxygen for extravehicular mobility unit (EMU) power generation. Issues verified include passive, zero-G product water removal, nonventing operation in the EMU duty cycle, and complete recovery of product water in potable form. The long cycle life and quick rechargeability are confirmed in 600 h of testing including 150 deep discharge cycles.

We have developed a novel approach for undergraduate laboratory education termed "interlaboratory collaboration" in which students in distinct laboratory courses are responsible for different aspects of a single project that spans these courses. This approach attempts to model the industrial workplace where separate groups are responsible for different aspects of a project. By having students synthesize or study a set of different compounds the students within a class can compare their data and investigate trends in chemical reactivity or physical properties. Students enrolled in both an inorganic synthesis and a physical chemistry laboratory course concurrently are assigned compounds to analyze that they did not synthesize. At the end of this process students share their findings with their peers. The approach has been well received by students and faculty, alike.

Digital subtraction angiography (DSA) performed via a peripheral vein was compared prospectively with selective conventional pulmonary angiography (CPA) in 54 patients suspected of having pulmonary embolism (PE). All patients also underwent ascending venography. In contrast to the conventional pulmonary angiograms, all of which were considered satisfactory, 13 of 54 digital subtraction angiograms (24%) were technically unsatisfactory. The interpretable digital subtraction angiograms had 81% sensitivity and 64% specificity. With DSA, one cannot exclude the diagnosis of PE on the basis of normal angiograms (27% false-positive results) as one can with perfusion scanning. On the other hand, DSA showed good sensitivity (94%) in medium to major PE. Therefore it may be the technique of choice in the screening of life-threatening PE for which curative emergency treatment with thrombolytic agents or embolectomy is often necessary.

The lung epithelial permeability to inhaled solutes is primarily attributed to the degree of distension of the interepithelial junctions and thus of the alveolar volume. To assess this hypothesis, a submicronic aerosol of technetium-99m-labeled diethylenetriamine pentaacetate (99mTc-DTPA) was inhaled by eight normal subjects in left lateral decubitus (LLD). The regional lung clearance of 99mTc-DTPA was measured in LLD, then in right lateral decubitus (RLD) to reverse the relative distension of the alveoli. Although in LLD the deposition of the aerosol is the greatest in the gravity-dependent regions of the left lung, their 99mTc-DTPA clearances are significantly lower than those of the nondependent regions of the right lung (0.7 +/- 0.3 vs. 2 +/- 0.8%/min, P less than 0.001). In RLD, these regions placed in opposite positions significantly reversed their clearances (1.6 +/- 0.8 vs. 0.6 +/- 0.2%/min, P less than 0.001). Results indicate in lateral decubitus a gravity gradient of 99mTc-DTPA clearances independent of the aerosol deposition. This gradient of epithelial permeability to solutes appears to be influenced by the gradient of alveolar volume.

Ventilation perfusion scanning fails to diagnose pulmonary embolism in matched defects. In 61 patients (19 with pulmonary embolism proved by angiography, 32 with chronic obstructive lung disease and 10 with acute bacterial pneumonia) we computed the ventilation perfusion ratio (V/Q) in these matched defects, using Krypton 81 m. This analysis demonstrated that the diagnosis of pulmonary embolism could be made with a specificity of 100% when the V/Q ratio was greater than 1.2 in the matched defects. Pulmonary embolism was characterized by a perfusion defect with a high V/Q ratio, even in Laennec infarction. In contrast, the analysis excluded the diagnosis of pulmonary embolism and suggested another disease when the V/Q was less than 0.95 with a specificity of 95%. Perfusion defects in acute pneumonia always had a V/Q less than 1. The diagnosis remained difficult in chronic obstructive lung disease when pulmonary embolism was suspected on subsegmental defects. Nevertheless this could be solved in about 50% of the cases by quantitative analysis. We feel, therefore, that ventilation perfusion scanning should be quantified by V/Q analysis to improve the diagnosis of pulmonary embolism.

The regional lung clearance of a deposited aerosol of [99mTc] diethylenetriaminepentaacetic acid was successively computed at rest and at exercise in seven nonsmoking volunteers in upright posture. The subjects were seated on a bicycle with their backs against a gamma camera. At rest there was a gradient of clearance from the apex to the base of the lung, the apical clearance being significantly higher. At exercise this regional gradient was enhanced by a large and significant increase of the apical clearances (3.40 +/- 0.63% min-1 s.d. compared with 1.82 +/- 0.75% min-1 s.d. at rest, n = 7, p less than 0.01). By contrast the changes of the basal clearances were slight and unsignificant (1.46 +/- 0.71% min-1 s.d. compared with 1.40 +/- 0.82% min-1 s.d.). This increase of the apical lung clearance could be attributed primarily to the increase of apical blood flow induced by exercise and to the subsequent increase of the permeability surface area product.

To understand the meaning of somatic changes to the adolescent and their possible effects on behavior, developmentalists have begun to examine maturational timing and status in detail. Efforts have been hampered by the necessity of obtaining somatic growth data by physician examination. In the present study, 3 self-report methods for rating secondary sexual characteristic growth were compared to physician ratings; the accuracy of self-reported height and weight also was assessed. Specifically, 151 11-, 12-, and 13-year-old girls rated their breast and pubic hair development using schematics of the 5 Tanner stages and filled out the Pubertal Development Scale (PDS); their mothers also rated their daughters' development using the Tanner stage schematics. The correlation with physician Tanner ratings was .82 for self-ratings, .85 for ratings by the mother, and between .61 and .67 for self-reports on the PDS. The correlations for self- and actual reports of weight and height were .98 and .75, respectively. The usefulness of the PDS, Tanner ratings, and self-reported height and weight as adequate estimates of pubertal development is discussed.

Long-term treatment must be considered in cases of chronic asthma. Its main purpose is to suppress or decrease the frequency of acute dyspneic episodes; however, it may be more difficult to improve the bronchial obstruction of the patients. In allergic broncho-pulmonary aspergillosis, the treatment aims to prevent irreversible bronchiectasis. The methods and surveillance of long-term treatment are discussed.

A case of a right-to-left intracardiac shunt caused by a right atrial myxoma is reported. Sudden hypoxaemia was the unique symptom. Measurement of Pao2 while the patient breathed pure oxygen demonstrated the presence of a shunt. Right heart catheterization showed a patent foramen ovale and a pressure gradient between the right atrium and the right ventricle, and between the right and the left atria, explaining the shunt. Cineangiography demonstrated a right atrial myxoma, which was surgically removed. This case report illustrates how a step-by-step diagnostic procedure, based on pathophysiology, may lead to such unexpected findings.

The development of a fuel cell energy storage system for the Space Station Extravehicular Mobility Unit (EMU) is discussed. The ion-exchange membrane fuel cell uses hydrogen stored as a metal hydride. Several features of the hydrogen-oxygen fuel cell are examined, including its construction, hydrogen storage, hydride recharge, water heat, water removal, and operational parameters.

The risk of early recurrence of pulmonary embolism in patients with venous thromboembolic disease treated by anticoagulants is not well established. To determine the risk linked to contemporary proximal deep venous thrombosis, a prospective study was organised to give clinical and scintigraphic surveillance to 50 patients with angiographically proved pulmonary embolism plus phlebographically proved proximal deep vein thrombosis during the first 15 days of anticoagulant treatment. Perfusion lung scans were performed initially and on days 3, 7, and 15. Only two patients had a recurrence of pulmonary embolism during this period; both episodes were revealed by new symptoms, and one recurrence was fatal. The systematic performance of angiography in four patients found to have new scintigraphic defects led to the diagnosis of "spurious scintigraphic recurrence" in three of them. It is concluded that (a) adjusted anticoagulant treatment showed an effectiveness of 96% for preventing early recurrence of pulmonary embolism in this group of supposed high risk patients, and (b) in patients with recent pulmonary embolism new defects on systematic perfusion lung scans are not specific indicators of recurrent pulmonary embolism.

Previous research indicates that the latency of learned responses is inversely related to the strength of the stimulus-response bond. If this is true for stuttering, then a word stuttered on the fi...