Targeted disruption of mouse long-chain acyl-CoA dehydrogenase gene reveals crucial roles for fatty acid oxidation

Abnormalities of fatty acid metabolism are recognized to play a significant role in human disease, but the mechanisms remain poorly understood. Long-chain acyl-CoA dehydrogenase (LCAD) catalyzes the initial step in mitochondrial fatty acid oxidation (FAO). We produced a mouse model of LCAD deficiency with severely impaired FAO. Matings between LCAD +/− mice yielded an abnormally low number of LCAD +/− and −/− offspring, indicating frequent gestational loss. LCAD −/− mice that reached birth appeared normal, but had severely reduced fasting tolerance with hepatic and cardiac lipidosis, hypoglycemia, elevated serum free fatty acids, and nonketotic dicarboxylic aciduria. Approximately 10% of adult LCAD −/− males developed cardiomyopathy, and sudden death was observed in 4 of 75 LCAD −/− mice. These results demonstrate the crucial roles of mitochondrial FAO and LCAD in vivo.     

Impact of HIV Counseling and Testing on HIV-Infected Men Who Have Sex with Men: The South Beach Health Survey

The impact of HIV counseling and testing on sexual risk-taking and related behaviors reported by HIV-infected men who have sex with men (MSM) was examined in a cross-sectional study conducted among a representative sample of residents living in a resort area. Participants provided specimens of oral mucosal transudate for HIV-antibody testing, were interviewed in their homes, and completed a self-administered questionnaire. Specimens were tested by modified ELISA and, if repeatedly positive, confirmed by Western blot. Of 205 men enrolled, 51 (24.9%) tested positive for antibody to HIV. All 51 had been counseled and tested for antibody to HIV-1 (median = 4 tests); 37 (74%) of 50 reported that their most recent test was positive. Twenty (39.2%) said they had engaged in unprotected insertive anal intercourse in the past year; 15 (29.4%) engaged in unprotected insertive anal intercourse with partners who may have been susceptible to HIV infection. Men who reported that their last HIV-antibody test was positive were three times more likely to have engaged in unprotected insertive anal intercourse in the past year (45.9%) as those who did not know they were infected with HIV (15.4%). Counseling and testing is ineffective as a measure for promoting behavior change among HIV-positive MSM in South Beach. More effective social and behavioral interventions must be developed, implemented, and evaluated.     

Biological variability in Wistar-Kyoto rats. Implications for research with the spontaneously hypertensive rat

The spontaneously hypertensive rat (SHR) initially bred in Kyoto is the most widely studied animal model of essential hypertension. As controls for the SHR, most workers have used normotensive descendants of Wistar rats from the colony in Kyoto from which the SHR strain was derived (Wistar-Kyoto rats, WKY). But the presumption that WKY are serviceable controls for SHR rests on the tacit assumption that all WKY constitute a single inbred strain. It appears, however, that whereas the National Institutes of Health distributed breeding stocks of SHR after they had been fully inbred (i.e., after 20 generations of brother-sister mating), the breeding stocks of WKY were distributed before they had been fully inbred. Accordingly, the biological variability of WKY may be greater than that of SHR. To investigate this possibility, we obtained SHR and WKY from two of the largest commercial suppliers in the United States and systematically measured the growth rate and blood pressure of these rats under identical physical and metabolic conditions. We found that WKY from one source differed from those of the other in both growth rate and blood pressure. In contrast, the SHR from the two suppliers were not different with respect to either growth rate or blood pressure. Because the National Institutes of Health may have distributed breeding stocks of WKY as early as the F6 generation, it is possible that rats currently designated as WKY do not constitute a single inbred strain. Thus, interpretation of studies employing "the Wistar-Kyoto rat strain" as a control for the SHR may be much more problematic than has previously been recognized.     

Modern management of non-chemotherapy drug-induced agranulocytosis: a monocentric cohort study of 90 cases and review of the literature

BACKGROUND: The present study reports a monocentric experience of 90 drug-induced agranulocytosis cases and discusses their management, in particular the role of hematopoietic growth factors. METHODS: Data from 90 patients with drug-induced agranulocytosis who met the criteria of the IAAAS group and of Bénichou and Solal-Celigny [Nouv Rev Fr Hematol 1993; 33: 257.] were retrospectively reviewed. All cases were extracted from a cohort study of the Hopitaux Universitaires de Strasbourg, France. Data were specifically analyzed with regard to the use of hematopoietic growth factors (in 42 patients). RESULTS: Mean patient age was 63 (range 17-95) years and the sex ratio (M/F) was 0.39. An underlying disease was present in 37% of the patients. Antibiotics (25%), antithyroid drugs (23%), and antiaggregative platelet agents (16%) were the most frequent causative drugs. Main clinical features included isolated fever (41%), septicemia or septic shock (31%), and pneumonia (10%). Mean neutrophil count was 0.13 (range 0-0.46)x10(9)/l. Outcome was favorable in 98% of patients. The mean durations of hematological recovery (neutrophil count over 1.5x10(9)/l), antibiotic therapy, and hospitalization was 8.5 (range 2-21) days, 9.2 (range 2-21) days, and 10.5 (range 3-23) days, respectively. All patients were treated with broad-spectrum antibiotics and 42 patients with hematopoietic growth factors. In these 42 patients, the mean durations for hematological recovery, antibiotic therapy, and hospitalization were significantly reduced at: 6.3 (range 2-16) days, 7.1 (range 2-16) days, and 9.1 (range 3-23) days, respectively (all P<0.05). CONCLUSIONS: The present study shows that new causative drugs are emerging (antibiotics, antithyroid, and antiaggregative platelet agents), that drug-induced agranulocytosis remains typically a serious accident with severe sepsis, and that modern management with broad spectrum antibiotics and hematopoietic growth factors may reduce the mortality.     

Esophageal achalasia secondary to mesothelioma

Summary Achalasia secondary to malignancy is rare, with most cases associated with gastric adenocarcinoma of the gastroesophageal junction. This report describes the clinicopathologic features of a 64-year-old man found to have mesothelioma as the cause of secondary achalasia. To our knowledge, this is the first case of secondary achalasia produced by a mesothelioma. We reviewed the English literature in regard to achalasia induced by tumors.This work was supported by the Veterans Administration.     

Perturbed hematopoiesis in individuals with germline DNMT3A overgrowth Tatton-Brown-Rahman syndrome

Tatton-Brown-Rahman syndrome (TBRS) is an overgrowth disorder caused by germline heterozygous mutations in the DNA methyltransferase DNMT3A. DNMT3A is a critical regulator of hematopoietic stem cell (HSC) differentiation and somatic DNMT3A mutations are frequent in hematologic malignancies and clonal hematopoiesis. Yet, the impact of constitutive DNMT3A mutation on hematopoiesis in TBRS is undefined. In order to establish how constitutive mutation of DNMT3A impacts blood development in TBRS we gathered clinical data and analyzed blood parameters in 18 individuals with TBRS. We also determined the distribution of major peripheral blood cell lineages by flow cytometric analyses. Our analyses revealed non-anemic macrocytosis, a relative decrease in lymphocytes and increase in neutrophils in TBRS individuals compared to unaffected controls. We were able to recapitulate these hematologic phenotypes in multiple murine models of TBRS and identified rare hematological and non-hematological malignancies associated with constitutive Dnmt3a mutation. We further show that loss of DNMT3A in TBRS is associated with an altered DNA methylation landscape in hematopoietic cells affecting regions critical to stem cell function and tumorigenesis. Overall, our data identify key hematopoietic effects driven by DNMT3A mutation with clinical implications for individuals with TBRS and DNMT3A-associated clonal hematopoiesis or malignancies.     

Advances in the processing, sterilization, and crosslinking of ultra-high molecular weight polyethylene for total joint arthroplasty.

Despite the recognized success and worldwide acceptance of total joint arthroplasty, wear is a major obstacle limiting the longevity of implanted UHMWPE components. Efforts to solve the wear problem in UHMWPE have spurred numerous detailed studies into the structure, morphology, and mechanical properties of the polymer at every stage of its production from original resin into stock material and final fabricated form. Scientific developments in this field are occurring at an accelerating rate, and periodic review of UHMWPE technology is therefore increasingly necessary. The present article provides a four-part comprehensive review of technological advancements in the processing, manufacture, sterilization, and crosslinking of UHMWPE for total joint replacements. The first part of this article describes the recently updated nomenclature of UHMWPE, including the process of resin production and conversion to stock material. The second part outlines the methods of manufacturing UHMWPE into joint replacement components and provides overviews of alternate forms of UHMWPE, namely carbon-fiber reinforced UHMWPE (Poly II) and UHMWPE recrystallized under high temperature and pressure (Hylamer). The third part summarizes the sterilization and degradation of UHMWPE. Newly developed methods for accelerating the oxidation of UHMWPE after sterilization (for preconditioning of test specimens), as well as methods for quantifying the oxidation of UHMWPE, are also discussed. Finally, the fourth part reviews the development and properties of crosslinked UHMWPE, a promising alternate biomaterial for total joint replacements.     

Therapist effects on functional analysis outcomes with young children

Analog functional analyses (FAs) are commonly used to assess factors that maintain problem behavior of individuals with intellectual disabilities. These analyses are usually conducted by trained staff in clinic settings. However, recent research suggests that FAs conducted by unfamiliar individuals, such as hospital or clinic staff, may result in inaccurate or at least different outcomes. This finding, though, has not been sufficiently examined with young children (i.e., under 5 years of age), where therapist familiarity likely has more influence. The current study compared the outcomes of FAs conducted by unfamiliar staff with FAs conducted by parents for five children ages 2–5 years. Results demonstrate that FAs conducted by unfamiliar therapists may result in a number of differing outcomes, including no responding from the child, failure to identify a particular behavioral function, and decreased rates of responding.