AIDS; new developments. I. HIV tests: time for a more active policy

Until recently, an HIV test was of limited importance for persons who had been at risk for HIV as effective drugs were not available. With the advent of a new generation of antiretroviral drugs with beneficial effect after early treatment, knowledge of the HIV serostatus has become of more importance to asymptomatic persons. There is no need for a mass screening campaign however, as there is no cure as yet.     

Putative liver progenitor cells: conditions for long-term survival in culture

BACKGROUND AND OBJECTIVES: We operated on three patients with leiomyosarcoma of the inferior vena cava. METHODS: Complete excision was possible in all three patients. RESULTS: One patient developed widespread metastasis at 23 months, one patient is alive with no evidence of disease at 70 months, and one patient is alive at 15 months. The third patient had subcutaneous and pulmonary metastases at the time of presentation, which are radiologically nondetectable at present following postoperative chemotherapy. CONCLUSIONS: The clinicopathologic features, prognostic factors, and treatment of 130 cases found in a comprehensive literature search and our three cases are reported.     

Mitogenic effect of retinoid X receptor agonists in rat liver

Thirty-nine acrylates and methacrylates that had been used in dental resin materials were evaluated by a cytotoxicity test, and the relationships between their structures and cytotoxicity were studied to predict cytotoxic levels of dental resin materials in order to develop new low-toxic resin materials. All the acrylates evaluated were more toxic than corresponding methacrylates. In both the acrylates and methacrylates, a hydroxyl group seemed to enhance cytotoxicity. Dimethacrylates with 14 or fewer oxyethylene chains showed similar cytotoxicity while dimethacrylates with 23 oxyethylene chains showed lower cytotoxicity. The cytotoxicity ranking of monomers widely used in dental resin materials was bisphenol A bis 2-hydroxypropyl methacrylate (bisGMA) > urethane dimethacrylate (UDMA) > triethyleneglycol dimethacrylate (3G) > 2-hydroxyethyl methacrylate (HEMA) > methyl methacrylate (MMA). In acrylates, methacrylates, and ethylmethacrylates with either substituents, the lipophilicity of substituents affected their cytotoxicity, and an inverse correlation between IC50 and logP was observed. These results will be useful in developing new resin materials with low toxic monomer compositions.     

Gastrointestinal autonomic nerve tumors. A clinicopathological, immunohistochemical, and ultrastructural study of 12 cases

The gastrointestinal autonomic nerve tumor (GAN tumor) is an uncommon stromal tumor of the intestinal tract and retroperitoneum first described by Herrera and associates in 1984. Distinction of GAN tumors from other gastrointestinal stromal tumors is based on electron microscopic findings. Thus far there have been 12 reported cases. We present an additional 12 GAN tumors, identified by us during 4 years. There were seven male and five female patients and they ranged in age from 10 to 85 years (mean: 58 years). Sites of the tumors were stomach (three), jejunum (two), ileum (four), mesentery (one), and retroperitoneum (two). Eight of the tumors measured > 10 cm in greatest dimension. Usually well circumscribed, the neoplasms were tan to light pink, sometimes hemorrhagic, and soft. There was a variety of histologic patterns including fascicles, palisades, and whorls. Mitotic activity varied from 0 to 23 mitosis per 10 high-power fields (HPF). Using a panel of 10 immunohistochemical stains, only vimentin was consistently positive. There was neuron-specific enolase reactivity in six and S-100 protein reactivity in two cases. All muscle markers were negative. Ultrastructural studies showed neuron-like cells with long axonic cytoplasmic processes ending in bulbous synapse-like structures containing dense-core neurosecretory granules and clear vesicles. Basement membrane was absent. These features are reminiscent of ganglia of the intestinal autonomic nervous system. The patients were followed for 5-125 months (mean of 26 months). Tumor recurred or metastasized to the liver in seven patients (58%) and four patients died with tumor. There were correlations between tumor size (> 10 cm), mitotic count (at least five per 10 HPF), and aggressive behavior.     

Peritraumatic dissociation and posttraumatic stress in male Vietnam theater veterans

OBJECTIVE: The aim of this study was to determine the reliability and validity of a proposed measure of peritraumatic dissociation and, as part of that effort, to determine the relationship between dissociative experiences during disturbing combat trauma and the subsequent development of posttraumatic stress disorder (PTSD). METHOD: A total of 251 male Vietnam theater veterans from the Clinical Examination Component of the National Vietnam Veterans Readjustment Study were examined to determine the relationship of war zone stress exposure, retrospective reports of dissociation during the most disturbing combat trauma events, and general dissociative tendencies with PTSD case determination. RESULTS: The total score on the Peritraumatic Dissociation Experiences Questionnaire--Rater Version was strongly associated with level of posttraumatic stress symptoms, level of stress exposure, and general dissociative tendencies and weakly associated with general psychopathology scales from the MMPI-2. Logistic regression analyses supported the incremental value of dissociation during trauma, over and above the contributions of level of war zone stress exposure and general dissociative tendencies, in accounting for PTSD case determination. CONCLUSIONS: These results provide support for the reliability and validity of the Peritraumatic Dissociation Experiences Questionnaire--Rater Version and for a trauma-dissociation linkage hypothesis: the greater the dissociation during traumatic stress exposure, the greater the likelihood of meeting criteria for current PTSD.     

Nucleotide-dependent movement of the epsilon subunit between alpha and beta subunits in the Escherichia coli F1F0-type ATPase

Mutants of ECF1-ATPase were generated, containing cysteine residues in one or more of the following positions: alphaSer-411, betaGlu-381, and epsilonSer-108, after which disulfide bridges could be created by CuCl2 induced oxidation in high yield between alpha and epsilon, beta and epsilon, alpha and gamma, beta and gamma (endogenous Cys-87), and alpha and beta. All of these cross-links lead to inhibition of ATP hydrolysis activity. In the two double mutants, containing a cysteine in epsilonSer-108 along with either the DELSEED region of beta (Glu-381) or the homologous region in alpha (Ser-411), there was a clear nucleotide dependence of the cross-link formation with the epsilon subunit. In betaE381C/epsilonS108C the beta-epsilon cross-link was obtained preferentially when Mg2+ and ADP + Pi (addition of MgCl2 + ATP) was present, while the alpha-epsilon cross-link product was strongly favored in the alphaS411C/epsilonS108C mutant in the Mg2+ ATP state (addition of MgCl2 + 5'-adenylyl-beta,gamma-imidodiphosphate). In the triple mutant alphaS411C/betaE381C/epsilonS108C, the epsilon subunit bound to the beta subunit in Mg2+-ADP and to the alpha subunit in Mg2+-ATP, indicating a significant movement of this subunit. The gamma subunit cross-linked to the beta subunit in higher yield in Mg2+-ATP than in Mg2+-ADP, and when possible, i.e. in the triple mutant, always preferred the interaction with the beta over the alpha subunit.     

Acid-base and electrolyte effects of shortening steeplechase in a three-day-event

This study was designed to characterise the acid-base and electrolyte effects of shortening the distance required during steeplechase (Phase B) in the face of hot and humid weather conditions during a treadmill-simulated Speed and Endurance test. Eight conditioned Thoroughbred horses underwent 3 randomised permutations of a standardised exercise test on a high speed treadmill. Each test consisted of trotting at 3.7 m/s for 10 min (Phase A); galloping at 11 m/s (Phase B) for 4 (cool laboratory conditions), 3 (hot and humid), or 2 (hot and humid) min; trotting at 3.7 m/s for 30 min (Phase C); and walking at 1.8 m/s for 10 min (Phase X). The treadmill slope was 4% for trotting and galloping and 0% for walking. Cool versus hot and humid conditions were 20 degrees C and 50-60% relative humidity vs. 26-28 degrees C and 80-85% relative humidity, respectively. Pulmonary artery blood samples were obtained at rest prior to exercise (Rest); at the end of Phases A (A10) and B (B2-4); at 10 (C10), 20 (C20) and 30 (C30) min through Phase C; and at 5 min into Phase X (X5). Additional samples for lactate (LA) and glucose (GLC) analysis were obtained 5 min into Phase C (C5) and at the end of Phase X (X10). Samples were analysed for packed cell volume (PCV), haemoglobin (HB), total plasma protein (TP), sodium (Na), potassium (K), chloride (Cl), anion gap (AG), plasma glucose (GLC) and lactate (LA), pH, PCO2, bicarbonate (HCO3) and base excess (BE). Shortening steeplechase distance by 50% under hot and humid conditions (2 min B) resulted in a consistent return to control measurements (4 min B) only for plasma LA. Changes in PCV, HB, TP, K and Cl were related more to the longer galloping distance in the 4 min B trials than to hot vs. cold laboratory conditions. Alternatively, changes in LA, GLC, pH, PCO2 and AG were more related to hot and humid laboratory conditions than they were to galloping distance. These latter variables, when combined with physical measures such as core temperature, bodyweight loss, point of fatigue on Phase C and recovery heart rates may serve as the best monitors of positive responses in future studies of proposed modifications to Phase C, rather than those variables which were more distance than weather-related.     

Intramuscular collagen characteristics of ram, wether, and zeranol-implanted ram lambs

Eighteen spring-born Columbia ram, wether, and zeranol-implanted ram lambs were studied to determine the influence of castration or zeranol implants on intramuscular collagen (IMC) properties and muscle shear force values. Warner-Bratzler shear force values for longissimus muscle were greatest for ram lambs, intermediate for implanted rams, and least for wethers (P < .05). Nonreducible collagen crosslink concentration was greater in IMC of rams and implanted rams (P < .05). The IMC from rams compared with that from wethers contained proportionately more Type III than Type I collagen (P < .05); values for implanted rams were intermediate. Heat-soluble muscle collagen concentration was greater for rams and implanted rams than for wethers (P < .05); however, insoluble collagen concentration did not differ by treatment. Muscle collagen concentrations were not different for rams, wethers, or implanted rams. Increased shear force values in rams were associated with elevated collagen crosslink concentration and increased proportion of Type III collagen. Greater concentration of soluble collagen in ram IMC neither diminished nor diluted IMC crosslinking. The proportion of heat-labile collagen in the fractions did not reflect the IMC crosslinking profile for ram and wether lambs. Zeranol implantation modified IMC characteristics of rams such that shear force values and some collagen properties were similar to those of wethers.