Prevalence and characteristics of rheumatic manifestations in patients infected with human immunodeficiency virus undergoing antiretroviral therapy.
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Anti-HIV Agents↗
Biomedical subjects
A Berman
Publications and source records attributed to A Berman.
Photoaffinity labeling of mefloquine-binding proteins in human serum, uninfected erythrocytes and Plasmodium falciparum-infected erythrocytes.
A photoreactive quinolinemethanol analog, N-[4-[1-hydroxy-2-(dibutylamino)ethyl]quinolin-8yl]-4- azido-2-salicylamide (ASA-MQ) has been synthesized which closely mimics the action of mefloquine. ASA-MQ possesses potent antimalarial activity against a mefloquine-sensitive strain of Plasmodium falciparum and shows decreased activity against a mefloquine-resistant parasite strain. Radioiodinated ASA-MQ has been used in photoaffinity labeling studies to identify mefloquine-interacting proteins in serum, uninfected erythrocytes and Plasmodium falciparum-infected erythrocytes. We have shown that mefloquine interacts specifically with apo-A1, the major protein of serum high density lipoproteins. In addition, mefloquine was shown to interact specifically with the erythrocyte membrane protein, band 7.2b (stomatin). A further two high affinity mefloquine-binding proteins with apparent molecular masses of 22 and 36 kDa were identified in three different strains of Plasmodium falciparum. We suggest that these two mefloquine-binding parasite proteins may be involved in the uptake of mefloquine or may represent macromolecular targets of mefloquine action in malaria parasites.
Affinity Labels↗
Human erythrocyte band 7.2b is preferentially labeled by a photoreactive phospholipid.
A head-group modified, photoreactive analog of phosphatidylethanolamine, N-([125I]iodo-4-azidosalicy- lamidyl)-1,2-dilauryl-sn-glycero-3-phosphatidylethanolamine ([125I]-N-ASA-DLPE), has been used in photoaffinity labeling studies of proteins of the human erythrocyte membrane. [125I]-N-ASA-DLPE was shown to be preferentially incorporated into a protein with an apparent molecular weight of 31 kDa. Protein sequencing and immunoprecipitation were used to identify this protein as the erythrocyte membrane protein, band 7.2b or stomatin. A sulphydryl-reactive ligand, 4-hydroxy-3-(iodo-[125I])-N-[2-(2-pyridinyldithio)ethyl]- benzenepropanamide ([125I]-PDA), was also shown to preferentially label band 7.2b. We propose that band 7.2b may act as a site of transbilayer reorientation of membrane phospholipids.
Affinity Labels↗
Comparison of four laboratory tests for diagnosis of Clostridium difficile-associated diarrhea.
Four different laboratory tests for diagnosis of Clostridium difficile-associated diarrhea were compared to determine the optimal one for management of patients with hospital-acquired diarrhea. Stool samples from 231 patients with diarrhea were tested by the following methods: culture for Clostridium difficile with subsequent determination of exotoxin production, with a toxigenic Clostridium difficile positive (TCP) result considered truly positive; enzyme immunoassay (EIA); latex agglutination test; and an immunobinding blot assay. The rates of positive results were as follows: EIA 5.5%, TCP 7.3%, latex agglutination 16.7%, and immunobinding blot assay 26.1%. Compared to the TCP results, the sensitivity and specificity were, respectively, 61 and 98% for EIA, 47 and 85% for latex agglutination, and 60 and 76% for the immunobinding blot assay. Samples from patients with > or = 6 stools/day were TCP and EIA positive in 27 and 17% of cases, respectively, whereas in patients with < 6 stools/day, these percentages decreased to 2 and 3%, respectively (p < 0.001). In hospitalized patients with > or = 6 stools/day, EIA appears to be the optimal test for diagnosis of Clostridium difficile-associated diarrhea, with a 73% positive predictive value and a 97% negative predictive value. However, in patients with < 6 stools/day, the prevalence of Clostridium difficile is low, and laboratory detection of this organism remains problematic.
Anti-Bacterial Agents↗
Interaction between inclusions embedded in membranes.
We calculate the membrane-induced interaction between inclusions, in terms of the membrane stretching and bending moduli and the spontaneous curvature. We find that the membrane-induced interaction between inclusions varies nonmonotonically as a function of the inclusion spacing. The location of the energy minimum depends on the spontaneous curvature and the membrane perturbation decay length, where the latter is set by the membrane moduli. The membrane perturbation energy increases with the inclusion radius. The Ornstein-Zernike theory, with the Percus-Yevick closure, is used to calculate the radial distribution function of inclusions. We find that when the spontaneous curvature is zero, the interaction between inclusions due to the membrane deformation is qualitatively similar to the hard-core interaction. However, in the case of finite spontaneous curvature, the effective interaction is dramatically modified.
Kinetics↗
[Limb injuries at the Aerodium hover sport facility in Eilat].
The Aerodium hover sport facility in Eilat has been in operation for the past 4 years and 33 patients have been treated for injuries caused by falls while hovering. The Aerodium is a new sport facility in Israel, similar to others in the US and Switzerland. It includes a 4-meter-wide wind tunnel with air pushed vertically upwards toward its center. Air flow velocity is adjustable and ranges between 120 and 140 km/hr, with a maximum of approximately 180 km/hr. Participants wear special suits and jump into the center of the column of air to hover. The hover suits are very wide, and puff up like a balloon; the sleeves and leggings have vents through which air escapes. Participants hover with their arms spread out and their legs slightly spread apart. The inexperienced hover at a height about 2 m. and the more experienced at heights of up to 5 m. During falls the person hovering lands on air mattresses surrounding the air column. Failure to follow rules and procedures, usually while changing limb position during hovering, can unbalance the inexperienced participant and lead to uncontrolled spins and falls.
Athletic Injuries↗
Effect of heat stress on follicular development during the estrous cycle in lactating dairy cattle.
In this study we examined, in two experiments, patterns of follicular development and dominance under conditions of heat stress. Estrous cycles were programmed to include two follicular waves (wave 1 and 2). On Day 1 of the estrous cycle (Day 0 = estrus), cows were assigned randomly to cooled (C; n = 6) or heat-stressed (H; n = 6) groups. In experiment 1, on Day 12 prostaglandin (PG) F2 alpha was injected and a controlled intravaginal drug release device (1.9 g progesterone) was inserted (this was removed on Day 17). In experiment 2, PGF 2 alpha was injected on Day 14. Ovarian structures were examined daily by ultrasonography, and blood samples were collected at each scanning. Cycle lengths were 20 and 17 days in experiments 1 and 2, respectively. Mean maximal body temperatures were higher (p < 0.01) in H (40.3 degrees C) than in C (38.8 degrees C) cows. In experiment 1, the rate of increase in number of large follicles (> or = 10 mm) was greater in H than in C cows (p < 0.01), resulting in 53% more large follicles in H cows during wave 1; this was associated with a lower (p < 0.05) number of medium-sized (6-9 mm) follicles between Days 7 and 10 of the cycle. Heat stress hastened (p < 0.02) the decrease in size of the first-wave dominant follicle and hastened (p < 0.01) the emergence of the second dominant (preovulatory) follicle by 2 days.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Sex differences in blood flow distribution of normothermic and heat-stressed rabbits.
Sex differences in blood flow (BF) distribution of male and female mature laboratory rabbits were determined in normothermic and heat-stressed states. Animals were anesthetized with alpha-chloralose, and BF distribution was determined by radioactive microspheres in the thermoneutral state and then again during hyperthermia after 2 h of heat exposure. Cardiac output did not change in either sex during heat stress. BF to the toe and ear skin and to nasal turbinates was lower in females than in males, whereas that to the diaphragm, sternum, intercostal muscles, spleen, and skeletal muscles was higher in females. A thermal state-by-sex interaction was detected in several organs, indicating that during heat stress in males, BF is significantly higher than in the controls, whereas in females a decline, no change, or only a slight increase was recorded. Males did not exhibit any decrease in inner organ BF during heat stress, whereas females did. Results show sex differences in BF distributions under normothermia and hyperthermia, suggesting that males and females differ in their BF regulation in both peripheral organs, which are active in heat dissipation, and inner body organs.
Animals↗
Interactions between body condition at calving and cooling of dairy cows during lactation in summer.
This study examined the interactions between dietary manipulation for increased body condition during the last trimester of pregnancy (spring) and postpartum cooling (summer lactation). Effects of diet on milk production of Holstein cows were examined to determine whether body stores could compensate for reduced DMI during heat stress. Cows calving between May and July with high (3.8 on a six-point scale) or low (2.7) body condition scores were assigned postpartum to be cooled by sprinkling and ventilation or to serve as uncooled controls. Cooled cows ate 1.6 kg more DM/d and consumed 9 L less of water/d than uncooled cows. Cooled cows maintained body temperatures below 38.9 degrees C during day hours; peak body temperature for uncooled cows was 39.7 degrees C. For 8 wk postpartum, glucose and insulin concentrations in plasma were unaltered by cooling or body condition. The NEFA were lower, and urea was slightly higher, for cows with low body condition. Milk production increased 1.9 kg/d with cooling, fat production increased with both body condition and cooling, and protein production increased with cooling but not with body condition. Performance was lowest for the uncooled subgroup with low body condition. Among cooled cows, no advantage was attributable to high body condition. An additive effect of high body condition and cooling on milk production in summer was not evident.
Animal Nutritional Physiological Phenomena↗
Immunodeficiency states and associated rheumatic manifestations.
For immunodeficiency states, the past year has been marked with the discovery of a series of events at the gene level and cell-to-cell interaction, particularly in common variable immunodeficiency, severe combined immunodeficiency, IgA deficiency, and immunodeficiency associated with IgM hyperimmunoglobulinemia. Clinical expression, especially in the musculoskeletal system, as well as infectious complications and therapy, also have been reported.
Common Variable Immunodeficiency↗
Bone mineral density in a native population of Argentina with low calcium intake.
OBJECTIVE: To determine the bone mineral density (BMD) of a group of natives from Tafi del Valle, Argentina, to examine possible differences compared to other populations. METHODS: BMD of lumbar spine and proximal femur was evaluated by dual x-ray absorptiometry (DEXA), in volunteer natives of El Potrerillo y El Rincon (descendants of the Amaichas and Quilmes). Forty-seven women and 31 men between 20 and 80 years of age were assessed. Average daily intake of calcium, physical activity level, serum levels of 25-OH vitamin D (25-OH-D), calcium, phosphorus and alkaline phosphatase were also determined. RESULTS: Average calcium intake was 345 +/- 22.4 mg/day (mean +/- SD). The average sunlight exposure was 3.8 +/- 0.44 h. Degree of physical activity was moderate/hard (grade 4) to very hard (grade 6) in those 60 yrs of age or younger. Laboratory values were normal except for 25-OH-D levels, which were significantly greater in Tafi del Valle (26.8 ng/ml) than in Buenos Aires (20.7 ng/ml); (p < 0.05) BMD of the proximal femur of both sexes was significantly greater compared to the reference groups; Z score of the female population was femoral neck: +/- 0.64 (p < 0.05); Ward's triangle: +/- 0.64 (p < 0.001); trochanter: +/- 0.90 (p < 0.001). Among men, femoral neck: +/- 0.53 (p < 0.01); Ward's triangle: +/- 1.45 (p < 0.001); trochanter: +/- 0.95 (p < 0.001). No significant differences were observed in the lumbar spine BMD. The high physical activity required by the mountainous land of Tafi del Valle may be the cause of increased BMD at the proximal femur among these people. High values of vitamin D produced by increased sun exposure can lead to greater absorption of calcium despite low calcium intake. CONCLUSION: Greater physical activity, higher levels of vitamin D, and racial factors in the native population could explain the greater BMD seen in the proximal femur despite low calcium intake.
Absorptiometry, Photon↗
Photoaffinity labelling of Plasmodium falciparum proteins involved in phospholipid transport.
Erythrocytes infected with mature-stage malaria parasites accumulate phospholipids from exogenous sources. We show that the transport of N-(7-nitrobenzy-2-oxa-1,3-diazol-4-yl)-1,2- dipalmitoyl-sn-glycero-3-phosphatidylethanolamine (N-NBD-DPPE), from the erythrocyte membrane to the intracellular malaria parasite, is dependent upon metabolic energy. A photoreactive phospholipid analogue, N-[125I]iodo-4-azidosalicylamidyl-1, 2-dilauryl-sn-glycero-3-phosphatidylethanolamine (N-125I-ASA-DLPE), has been synthesised and used in an attempt to identify proteins involved in phospholipid trafficking in malaria-infected erythrocytes. This photoreactive probe was found to preferentially label a protein with an apparent molecular weight of 22 kDa. Photolabelling of the 22-kDa protein was enhanced upon ATP depletion of malaria-infected erythrocytes.
Adenosine Triphosphate↗
Diurnal fluctuations in plasma ions and water intake of dairy cows as affected by lactation in warm weather.
The presumption that water, Na, K, and Cl homeostasis is affected by the initiation of lactation, especially in hot weather, was examined. The study was conducted using five Israel Holstein cows at 1 to 2 wk before parturition (period 1) and at 2 wk (initiation of lactation) and 7 wk (established lactation) postpartum (periods 2 and 3, respectively). In period 1, most water intake was related to feed (in the absence of overt Na or osmotic stimuli). In contrast, during lactation, drinking was probably a combined response to feed-related and hypertonicity stimuli. Diurnal fluctuations in plasma ions, frequency of drinking, and volume ingested at each drinking increased postpartum. In period 2, plasma ion concentrations still were regulated around mean values, which was not the case in period 3, during which large diurnal variation in mean values occurred. The lowest values and highest variabilities were recorded in period 3 at midday. With the transition from the dry period to lactation, plasma concentrations of Na and Cl were reduced and became more labile, but the relationships between them remained stable. Plasma K seemed to vary independently of the two other ions. The reduced homeostatic efficiency of plasma ions during early and established lactation in hot weather may have consisted of an accumulation of their deficiencies, enhanced excretion of K in sweat, and sequestration of Na and Cl in the rumen.
Animals↗
Adhesion of mouse hepatocytes to type I collagen: role of supramolecular forms and effect of proteolytic degradation.
Mouse hepatocytes were found to adhere much stronger to intact native type I collagen than to native, telopeptide-devoid collagen. Removal of telopeptides (by pepsin treatment) caused disintegration of supramolecular collagen aggregates. Similar differences in hepatocyte adhesion were observed between oligomeric and monomeric collagens separated from intact native preparations. It was concluded that the more active cell binding to intact collagen is due to a higher binding affinity of hepatocytes to supramolecular (oligomeric) forms of type I collagen. Heat denturation did not affect cell adhesion to intact collagen but restored adhesion to telopeptide-devoid substrates. Cell adhesion to denatured collagen was RGD-dependent whereas adhesion to native substrates proved RGD-independent. These data provide the first evidence of the role of supramolecular arrangement and the effect of proteolytic degradation of type I collagen on its adhesive behavior.
Amino Acid Sequence↗
Cytoreductive surgery prior to interleukin-2-based therapy in patients with metastatic renal cell carcinoma.
From May 1985 to December 1990, 93 patients with the clinical diagnosis of metastatic renal cell carcinoma and their primary tumor in place were evaluated for cytoreductive surgery as preparation for systemic therapy with regimens based on interleukin-2. These patients had typical sites of metastatic disease and manifestations of paraneoplastic syndromes. Patients underwent removal of the primary tumor, as well as debulking when this could be performed safely. Thirty-two percent of patients (30/93) had a second surgical resection in addition to their nephrectomy, frequently because of the large size of the primary tumor and its invasion of adjacent structures. Thirteen percent of patients (12/93) experienced postoperative complications. There were no perioperative mortalities. Forty percent of patients (37/93) who underwent nephrectomy could not be treated with immunotherapy, usually because of progression of disease. A preoperative ECOG status greater than or equal to 2 was the only significant risk factor associated with failure to undergo immunotherapy (P = 0.043). The response rate to immunotherapy in the 56 patients receiving interleukin-2 was 27 percent (4 CR, 11 PR).
Adolescent↗
Suicidality in hospitalized adolescents: relationship to prior abuse.
The effects of admission status, prior abuse, and the frequency and duration of both physical and sexual abuse on measures of suicidality for a sample of 117 hospitalized adolescents were investigated. Having been abused was found to have a significant association with the number of previous suicide attempts and to interact with the variable of admission status in measures of suicide ideation.
Adolescent↗
A mathematical model of oscillatory insulin secretion.
Insulin is secreted in sustained oscillatory fashion from isolated islets of Langerhans. This finding has led to the assumption of an underlying synchronizing process that coordinates insulin oscillations. This assumption was tested by developing a mathematical model of oscillatory insulin secretion in which we included degree of synchrony as a parameter. We first evaluated insulin oscillations in perifused isolated rat islets, using spectral analysis to determine their regularity and frequency. A parsimonious mathematical model was developed to account for these characteristics. The model postulates a group of secretory units discharging at discrete intervals with the same underlying period. Variation from two sources, phase differences between units (synchrony) and regularity within units, is introduced by adding two normally distributed random variables with standard deviations (Sg and Si, respectively) to the secretory period. Sets of 100 simulations for different values of Sg and Si were run. Results of the simulations suggest that the system tolerates a relatively large degree of asynchrony yet still demonstrates regularity of oscillations on spectral analysis. Comparison with perifusion data suggests that a moderate degree of asynchrony between islets can best account for the pattern of insulin oscillations observed. This model provides a theoretical basis for the study of mechanisms for insulin oscillations.
Adenoma↗
Effect of heat stress on tonic and GnRH-induced gonadotrophin secretion in relation to concentration of oestradiol in plasma of cyclic cows.
Effects of acute and seasonal heat stress on tonic and GnRH-induced LH and FSH secretion were examined during the early follicular phase of the oestrous cycle of cows (n = 40). Prostaglandin F2 alpha was injected on day 11 +/- 1 of the oestrous cycle and on the next day blood samples were collected at intervals of 15-20 min for 14 h, and i.m. injection of GnRH was given after 7 h. Treatments compared were control versus acute heat stress during blood sampling in winter, and cooled versus chronic heat stress in summer. Before GnRH injection, chronic heat stress in summer did not affect basal concentrations of plasma LH, but did lower LH pulse amplitude. However, in cows with low plasma oestradiol (1.9 +/- 0.2 pg ml-1), the mean and basal concentrations and amplitude of tonic LH pulses were reduced by heat stress (3.1, 2.1 and 4.8 versus 1.9, 1.4 and 2.5 ng ml-1, respectively). In cows with high plasma oestradiol (6.3 +/- 0.5 pg ml-1), these parameters were not affected. In chronically heat stressed cows in summer, GnRH-induced increases in plasma LH and FSH concentrations were the same as in the cooled controls. However, in cows with low plasma oestradiol, mean concentrations of FSH in plasma (31.8 versus 25.5 ng ml-1), the peak of the GnRH-induced FSH and LH surge (FSH 47.4 versus 35.6 ng ml-1, LH 50.7 versus 37.3 ng ml-1) and the shape of the GnRH-induced FSH and LH curves (treatment by time interaction) were significantly lower in non-cooled versus cooled controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗