Hodgkin lymphoma is as common as non-Hodgkin lymphoma in HIV-positive patients with sustained viral suppression and limited immune deficiency: a prospective cohort study.

OBJECTIVES: The incidence of HIV-related non-Hodgkin lymphoma (NHL) but not that of Hodgkin lymphoma (HL) has been declining. The aim of the study was to compare HIV-infected patients with NHL and HL with respect to antiretroviral therapy (ART) exposure at the time of lymphoma diagnosis. METHODS: HIV-infected patients with NHL and HL included in a prospective multicentre cohort study since January 2005 were compared with respect to ART exposure and viral load at the time of lymphoma diagnosis. RESULTS: As of 31 December 2012, data for 329 patients with NHL and 86 patients with HL from 31 participating centres were available. Patients with HL were more likely to be on ART (73.5% vs. 39.1%, respectively; P < 0.001) and more frequently had a viral load below the detection limit (57.3% vs. 27.9%, respectively; P < 0.001) than patients with NHL. The proportion of patients with HL was 8.0% in ART-naïve patients, 34.8% in patients with current HIV RNA < 50 HIV-1 RNA copies/mL, and 50.0% in patients with both HIV RNA < 50 copies/mL for > 12 months and a CD4 cell count of > 200 cells/µL. Of note, 45.8% of all patients with NHL were not currently on ART and had a CD4 count of < 350 cells/µL. CONCLUSIONS: This prospective cohort study shows that HL was as common as NHL in patients with sustained viral suppression and limited immune deficiency. In contrast to NHL, the majority of patients with HL were on effective ART, suggesting that ART provides insufficient protection from developing HL. The high proportion of untreated patients with NHL suggests missed opportunities for earlier initiation of ART.

Therapy and prophylaxis of opportunistic infections in HIV-infected patients: a guideline by the German and Austrian AIDS societies (DAIG/ÖAG) (AWMF 055/066).

INTRODUCTION: There was a growing need for practical guidelines for the most common OIs in Germany and Austria under consideration of the local epidemiological conditions. MATERIALS AND METHODS: The German and Austrian AIDS societies developed these guidelines between March 2010 and November 2011. A structured Medline research was performed for 12 diseases, namely Immune reconstitution inflammatory syndrome, Pneumocystis jiroveci pneumonia, cerebral toxoplasmosis, cytomegalovirus manifestations, candidiasis, herpes simplex virus infections, varizella zoster virus infections, progressive multifocal leucencephalopathy, cryptosporidiosis, cryptococcosis, nontuberculosis mycobacteria infections and tuberculosis. Due to the lack of evidence by randomized controlled trials, part of the guidelines reflects expert opinions. The German version was accepted by the German and Austrian AIDS Societies and was previously published by the Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF; German Association of the Scientific Medical Societies). CONCLUSION: The review presented here is a translation of a short version of the German-Austrian Guidelines of opportunistic infections in HIV patients. These guidelines are well-accepted in a clinical setting in both Germany and Austria. They lead to a similar treatment of a heterogeneous group of patients in these countries.

Carbamoyl phosphate synthetase: a tunnel runs through it.

The direct transfer of metabolites from one protein to another in a biochemical pathway or between one active site and another within a single enzyme has been described as substrate channeling. The first structural visualization of such a phenomenon was provided by the X-ray crystallographic analysis of tryptophan synthase, in which a tunnel of approximately 25 A in length was observed. The recently determined three-dimensional structure of carbamoyl phosphate synthetase sets a new long distance record in that the three active sites are separated by nearly 100 A.

3-T MRI reveals cranial and thoracic inflammatory changes in giant cell arteritis.

Giant cell arteritis (GCA) is a diagnostic challenge. The correct diagnosis is needed for immediate initiation of corticosteroid treatment since blindness is a dreaded complication. Typically, the superficial cranial arteries are affected by this granulomatous vasculitis of large- and medium-sized arteries. However, GCA is not limited to the cranial arteries. Involvement of various arteries such as the cervical and thoracic arteries can also occur. Here, we report a case of histologically proven GCA with cranial and extracranial involvement. We illustrate the usefulness of a comprehensive vascular high-resolution magnetic resonance imaging examination that combines assessment of mural inflammatory changes of the small temporal and occipital arteries with the evaluation of extracranial vasculature to assist in the difficult non-invasive diagnosis and to determine the extent of this inflammatory disease.

Carbamoyl phosphate synthetase: a crooked path from substrates to products.

The formation of carbamoyl phosphate is catalyzed by a single enzyme using glutamine, bicarbonate and two molecules of ATP via a reaction mechanism that requires a minimum of four consecutive reactions and three unstable intermediates. The recently determined X-ray crystal structure of carbamoyl phosphate synthetase has revealed the location of three separate active sites connected by two molecular tunnels that run through the interior of the protein. It has been demonstrated that the amidotransferase domain within the small subunit of the enzyme from Escherichia coli hydrolyzes glutamine to ammonia via a thioester intermediate with Cys269. The ammonia migrates through the interior of the protein, where it reacts with carboxy phosphate to produce the carbamate intermediate. The carboxy phosphate intermediate is formed by the phosphorylation of bicarbonate by ATP at a site contained within the amino-terminal half of the large subunit. The carbamate intermediate is transported through the interior of the protein to a second site within the carboxy-terminal half of the large subunit, where it is phosphorylated by another ATP to yield the final product, carbamoyl phosphate. The entire journey from substrate to product covers a distance of nearly 100 A.

High-resolution X-ray structure of UDP-galactose 4-epimerase complexed with UDP-phenol.

UDP-galactose 4-epimerase from Escherichia coli catalyzes the interconversion of UDP-glucose and UDP-galactose. In recent years, the enzyme has been the subject of intensive investigation due in part to its ability to facilitate nonstereospecific hydride transfer between beta-NADH and a 4-keto hexopyranose intermediate. The first molecular model of the epimerase from E. coli was solved to 2.5 A resolution with crystals grown in the presence of a substrate analogue, UDP-phenol (Bauer AJ, Rayment I, Frey PA, Holden HM, 1992, Proteins Struct Funct Genet 12:372-381). There were concerns at the time that the inhibitor did not adequately mimic the sugar moiety of a true substrate. Here we describe the high-resolution X-ray crystal structure of the ternary complex of UDP-galactose 4-epimerase with NADH and UDP-phenol. The model was refined to 1.8 A resolution with a final overall R-factor of 18.6%. This high-resolution structural analysis demonstrates that the original concerns were unfounded and that, in fact, UDP-phenol and UDP-glucose bind similarly. The carboxamide groups of the dinucleotides, in both subunits, are displaced significantly from the planes of the nicotinamide rings by hydrogen bonding interactions with Ser 124 and Tyr 149. UDP-galactose 4-epimerase belongs to a family of enzymes known as the short-chain dehydrogenases, which contain a characteristic Tyr-Lys couple thought to be important for catalysis. The epimerase/NADH/UDP-phenol model presented here represents a well-defined ternary complex for this family of proteins and, as such, provides important information regarding the possible role of the Tyr-Lys couple in the reaction mechanism.

Structure of the beta 2 homodimer of bacterial luciferase from Vibrio harveyi: X-ray analysis of a kinetic protein folding trap.

Luciferase, as isolated from Vibrio harveyi, is an alpha beta heterodimer. When allowed to fold in the absence of the alpha subunit, either in vitro or in vivo, the beta subunit of enzyme will form a kinetically stable homodimer that does not unfold even after prolonged incubation in 5 M urea at pH 7.0 and 18 degrees C. This form of the beta subunit, arising via kinetic partitioning on the folding pathway, appears to constitute a kinetically trapped alternative to the heterodimeric enzyme (Sinclair JF, Ziegler MM, Baldwin TO. 1994. Kinetic partitioning during protein folding yields multiple native states. Nature Struct Biol 1: 320-326). Here we describe the X-ray crystal structure of the beta 2 homodimer of luciferase from V. harveyi determined and refined at 1.95 A resolution. Crystals employed in the investigational belonged to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions of a = 58.8 A, b = 62.0 A, and c = 218.2 A and contained one dimer per asymmetric unit. Like that observed in the functional luciferase alpha beta heterodimer, the major tertiary structural motif of each beta subunit consists of an (alpha/beta)8 barrel (Fisher AJ, Raushel FM, Baldwin TO, Rayment I. 1995. Three-dimensional structure of bacterial luciferase from Vibrio harveyi at 2.4 A resolution. Biochemistry 34: 6581-6586). The root-mean-square deviation of the alpha-carbon coordinates between the beta subunits of the hetero- and homodimers is 0.7 A. This high resolution X-ray analysis demonstrated that "domain" or "loop" swapping has not occurred upon formation of the beta 2 homodimer and thus the stability of the beta 2 species to denaturation cannot be explained in such simple terms. In fact, the subunit:subunit interfaces observed in both the beta 2 homodimer and alpha beta heterodimer are remarkably similar in hydrogen-bonding patterns and buried surface areas.

The nutritional and metabolic effects of a carbohydrate-rich diet in a glycogen supercompensation training regimen.

It has been suggested that glycogen depletion followed by a protein-fat diet and a carbohydrate-rich diet improves performance. This study was designed to determine the nutritional and metabolic effects of a carbohydrate-rich diet in a glycogen supercompensation training regimen. Four male subjects participated in a 5-week protocol of which the first 3 weeks were devoted to a control period and the last 2 weeks to the experimental phase of the study. The variables measured before, during, and following the experimental phase included anthropometric and basal metabolic rate measurements, urinary and serum analysis for vitamins, SMA 12/60 blood profile and aerobic performance (VO2max). Results indicated an appreciable modification of the metabolic and nutritional profile of the subjects as a result of the diets. During the protein-fat diet there was a decrease in serum glucose and resting respiratory quotient and an increase in cholesterol, blood urea nitrogen, riboflavin, and N1-methylnicotinamide excretion. Subsequent to the carbohydrate-rich diet there was an increase in triglycerides and vitamin C, riboflavin, and thiamin excretion while there was a decrease in serum blood urea nitrogen, and N1-methylnicotinamide excretion. Aerobic performance was slightly decreased and the mean postexercise lactate levels were slightly higher after the carbohydrate-rich diet. It was hypothesized that the reduced niacin intake during the carohydrate-rich diet may hamper the aerobic oxidative pathways.

Steroidal allylic fluorination using diethylaminosulfur trifluoride: a convenient method for the synthesis of 3 beta-acetoxy-7 alpha- and 7 beta-fluoroandrost-5-en-17-one.

This paper discusses our findings regarding fluorination of the diastereomeric 3 beta-acetoxy-7-hydroxyandrost-5-en-17-ones (3 and 4) at the allylic 7-hydroxyl group using diethylaminosulfur trifluoride under various experimental conditions. The reaction led to the formation of allylic 7 alpha- and 7 beta-fluoro derivatives, 6 and 7, contaminated with small amounts of 3 beta-acetoxy-5 alpha-fluoroandrost-6-en-17-one (8), the rearrangement product, and 3 beta-acetoxyandrosta-4,6-dien-17-one (9), the elimination product. However, synthesis of 3 beta-acetoxy-7 alpha-fluoroandrost-5-en-17-one (6) and 3 beta-acetoxy-7 beta-fluoroandrost-5-en-17-one (7) has been achieved in high isomeric purity by careful manipulation of the experimental conditions. Also included herein is a convenient chemical synthesis of pure 3 beta-acetoxy-7 alpha-hydroxyandrost-5-en-17-one (4) and 3 beta-acetoxy-7 beta-hydroxyandrost-5-en-17-one (3), the starting materials for the present fluorination reaction. The structure of a degradation product, 3 beta-acetoxy-5 alpha-hydroxyandrost-6-en-17-one (5), has been established by X-ray diffraction analysis to ascertain unambiguously its absolute configuration.

Continuous versus intermittent exercise effects on urinary excretion of albumin and total protein.

Several studies have reported post-exercise increases of urinary concentrations of plasma proteins. However, under normal conditions, through mechanisms of size and electrical charge selection, the kidney restricts the clearance of molecules as large as albumin. Post-exercise increases in albuminuria occur following the physiological stress of intense exercise, most likely as a result of the exercise induced blood acidity changes which lead to a change in the arrangement of the albumin molecule, and subsequently the filtration characteristics of the glomerular capillary wall. The purpose of the present study was therefore to determine the extent to which different types of exercise could induce a transient condition of post-exercise increases in the urinary output of total protein and albumin. All 14 males, who agreed to participate in the study, performed a continuous and an intermittent cycling protocol on a stationary bicycle ergometer. The results showed that: a) intermittent exercise had a greater influence than continuous exercise on the total output of urine albumin, and of urine total protein; b) concentrations of blood pH and blood lactate, were associated with changes in the clearance of urine albumin and urine total protein. Post-exercise proteinuria response seems to be transient and therefore renal trauma is not suspected at the early stages of observation. Furthermore, these results indicate that the kidney undergoes distinct physiological adjustments during exercise, and that these adjustments are relative to the intensity of the exercise stress.

Physiological effects of inspiratory resistance on progressive aerobic work.

The purpose of this study was to determine the potential effects on progressive aerobic work while breathing through a new military type chemical and biological (CB) respirator loaded with three different types of purifying canisters. Twelve healthy well-motivated male subjects (mean age 23 +/- 3 years) participated in the study. Results indicated that mean maximal oxygen uptake (VO2max), time to exhaustion, respiratory exchange ratio, rate of perceived exertion, respiratory rate and tidal volume at exhaustion, maximal lactate and the 2-min post-exercise lactate were not significantly influenced when breathing with the respirator and the canisters in comparison to a laboratory valve. Mean pulmonary ventilation, however, was reduced by 21% while oxygen and carbon dioxide ventilatory equivalents were significantly lower by 9% and 8% respectively. Review of the stage-by-stage responses to the treadmill test between the laboratory valve and respirator/canister conditions indicated no significant differences (NS) in oxygen uptake but slightly lower heart rates (NS). Ventilation was not influenced by the canisters until 80% of VO2max at which time the mean oxygen ventilatory equivalent became significantly lower. Blood lactate was significantly depressed between 60% and 90% VO2max under the respirator/canister conditions. It was concluded that, although physiological adaptation occurred, breathing with the new CB respirator and each of the three purifying canisters had no detrimental effect on progressive aerobic work to exhaustion. However, prolonged work at intensities greater than 80-85% of VO2max would in all probability be impaired when breathing with the CB mask and the canisters.

Dramatic differences in the binding of UDP-galactose and UDP-glucose to UDP-galactose 4-epimerase from Escherichia coli.

UDP-galactose 4-epimerase catalyzes the interconversion of UDP-galactose and UDP-glucose during normal galactose metabolism. Within recent years the enzyme from Escherichia coli has been studied extensively by both biochemical and X-ray crystallographic techniques. One of several key features in the catalytic mechanism of the enzyme involves the putative rotation of a 4'-ketopyranose intermediate within the active site region. The mode of binding of UDP-glucose to epimerase is well understood on the basis of previous high-resolution X-ray crystallographic investigations from this laboratory with an enzyme/NADH/UDP-glucose abortive complex. Attempts to prepare an enzyme/NADH/UDP-galactose abortive complex always failed, however, in that UDP-glucose rather than UDP-galactose was observed binding in the active site. In an effort to prepare an abortive complex with UDP-galactose, a site-directed mutant protein was constructed in which Ser 124 and Tyr 149, known to play critical roles in catalysis, were substituted with alanine and phenylalanine residues, respectively. With this double mutant it was possible to crystallize and solve the three-dimensional structures of reduced epimerase in the presence of UDP-glucose or UDP-galactose to high resolution. This study represents the first direct observation of UDP-galactose binding to epimerase and lends strong structural support for a catalytic mechanism in which there is free rotation of a 4'-ketopyranose intermediate within the active site cleft of the enzyme.

Reproducibility of body temperature response to standardized test conditions when assessing clothing.

The traditional use of core temperature to assess the thermal effects of clothing has recently been questioned. The purpose of this study was to assess the reproducibility of body temperature in five subjects (mean age, 22.6 +/- 1.5 years) wearing either athletic clothing or a chemical protective overgarment while exercising at 20 degrees C and at 40 degrees C. The exercise was preceded by a 1 h adaptation period in a controlled environmental chamber. Results indicated that mean group change in rectal temperature (delta Tr) appeared to be reproducible for both garment ensembles at 20 degrees C but not at 40 degrees C. For mean change in oesophageal temperature (delta T(oes)) at 20 degrees C, reproducibility was obtained for the overgarment but not for the athletic garment; at 40 degrees C, mean delta T(oes) appeared to be reproducible with both garments. However, when individual responses were examined, there was little reproducibility for either delta Tr or delta T(oes). In addition, these measurements failed to show differences in the types of clothing worn. It was concluded that the use of core temperature to assess heat stress imposed by wearing clothing during exercise may lead to erroneous conclusions.

A comparison of human thermoregulatory response following dynamic exercise and warm-water immersion.

We tested the hypothesis that the prolonged elevated plateau of esophageal temperature (Tes) following moderate exercise is a function of some exercise-related factors and not the increase in heat content and Tes during exercise, by comparing the response to increase Tes during exercise (endogenous heating) and warm-water immersion (exogenous heating). Nine healthy, young [24.0 (1.9) years] subjects performed two separate experiments: (1) 15 min of treadmill exercise at 70% (VO2max) and 15 min rest in a climatic chamber at 29 degrees C, followed by 15 min of immersion in a 42 degrees C water bath and a further 60 min of recovery in the climatic chamber [exercise-water (EW)]; and (2) 15 min of immersion in a 42 degrees C water bath followed by 60 min of recovery in the climatic chamber [water-only (WO)]. Esophageal (Tes) and skin (Tsk) temperatures were recorded at 5-s intervals throughout. The Tes at which the forearm to finger temperature gradient (Tfa-Tfi) abruptly decreases was used to identify the threshold for forearm cutaneous vessel dilation (Thdil) during exercise. Pre-exercise Tes values were 36.64 degrees C and 36.74 degrees C for EW and WO respectively. The EW post-exercise Tes value fell to a stable level of 37.12 degrees C and this value differed by 0.48 degree C (P < 0.05) from baseline, but was similar to Thdil (37.09 degrees C). Despite a 1.2 degrees C increase in Tes during the subsequent warm-water immersion, Tes returned to the post-exercise value (37.11 degrees C). The WO post-immersion Tes fell to a stable plateau of 36.9 degrees C, which was not statistically different from the pre-immersion Tes. The data for both warm-water treatments support the hypothesis that increases in Tes and heat content alone are not the primary mechanisms for the post-exercise elevation in Tes and Thdil. These data also support our previous observation that the exercise-induced elevation in Thdil persists into recovery.

The influence of extracellular buffer concentration and propionate on lactate efflux from frog muscle.

Lactate efflux from frog sartorius muscles was measured following a lactate load of about 18 mumol X g-1 induced by a 4-min period of stimulation. Lactate efflux rate was buffer concentration dependent. The initial efflux rate increased from about 150 nmol X g-1 X min-1 in 1 mM MOPS buffer to 400 nmol X g-1 X min-1 in 25 mM MOPS buffer. The addition of 20 mM propionate reduced mean intracellular pH by about 0.2 units and increased lactate efflux rate by 70% at the highest buffer concentration and 400% at the lowest buffer concentration. The observed results are in reasonable agreement with predictions based on a model in which net efflux is limited by diffusion of both buffer and lactate in the extracellular space. Transmembrane lactate efflux appears to consist of two components, one of which is proton linked and carried either by undissociated lactic acid or coupled proton-lactate transport, the other being carried by independent lactate ions.

Effect of inspiratory resistance to prolonged exercise in a hot environment wearing protective clothing.

The effects of inspiratory resistance on prolonged work in a hot environment wearing a nuclear, bacteriological and chemical warfare (NBCW) mask and overgarment were assessed in 10 males. Subjects walked on a treadmill at 5 km/hr, 2% gradient, until their core temperature reached 39 degrees C or for a duration of 90 min. Rectal temperature, heart rate, ventilation, oxygen consumption and rate of perceived breathing were measured. There were no differences between break-point time without the canister (62.2 +/- 21 min) and with the canister (58.9 +/- 17 min). Regression analysis indicated that the mean core temperature increased by 0.02 degrees C for every minute of work performed and heart rate by 6 beats/min for every increase of 0.2 degrees C in core temperature. Reduction in heat transfer brought about by wearing the protective overgarment and mask with or without the canister will significantly increase core temperature and limit the performance of moderate work to approximately 1 h in a moderately fit individual.

Molecular structures of the S124A, S124T, and S124V site-directed mutants of UDP-galactose 4-epimerase from Escherichia coli.

UDP-galactose 4-epimerase plays a critical role in sugar metabolism by catalyzing the interconversion of UDP-galactose and UDP-glucose. Originally, it was assumed that the enzyme contained a "traditional" catalytic base that served to abstract a proton from the 4'-hydroxyl group of the UDP-glucose or UDP-galactose substrates during the course of the reaction. However, recent high-resolution X-ray crystallographic analyses of the protein from Escherichia coli have demonstrated the lack of an aspartate, a glutamate, or a histidine residue properly oriented within the active site cleft for serving such a functional role. Rather, the X-ray crystallographic investigation of the epimerase.NADH.UDP-glucose abortive complex from this laboratory has shown that both Ser 124 and Tyr 149 are located within hydrogen bonding distance to the 4'- and 3'-hydroxyl groups of the sugar, respectively. To test the structural role of Ser 124 in the reaction mechanism of epimerase, three site-directed mutant proteins, namely S124A, S124T, and S124V, were constructed and crystals of the S124A.NADH.UDP, S124A.NADH.UDP-glucose, S124T. NADH.UDP-glucose, and S124V.NADH.UDP-glucose complexes were grown. All of the crystals employed in this investigation belonged to the space group P3221 with the following unit cell dimensions: a = b = 83.8 A, c = 108.4 A, and one subunit per asymmetric unit. X-ray data sets were collected to at least 2.15 A resolution, and each protein model was subsequently refined to an R value of lower than 19.0% for all measured X-ray data. The investigations described here demonstrate that the decreases in enzymatic activities observed for these mutant proteins are due to the loss of a properly positioned hydroxyl group at position 124 and not to major tertiary and quaternary structural perturbations. In addition, these structures demonstrate the importance of a hydroxyl group at position 124 in stabilizing the anti conformation of the nicotinamide ring as observed in the previous structural analysis of the epimerase.NADH. UDP complex.