Identification and analysis of genes involved in anaerobic toluene metabolism by strain T1: putative role of a glycine free radical

The denitrifying strain T1 is able to grow with toluene serving as its sole carbon source. Two mutants which have defects in this toluene utilization pathway have been characterized. A clone has been isolated, and subclones which contain tutD and tutE, two genes in the T1 toluene metabolic pathway, have been generated. The tutD gene codes for an 864-amino-acid protein with a calculated molecular mass of 97,600 Da. The tutE gene codes for a 375-amino-acid protein with a calculated molecular mass of 41,300 Da. Two additional small open reading frames have been identified, but their role is not known. The TutE protein has homology to pyruvate formate-lyase activating enzymes. The TutD protein has homology to pyruvate formate-lyase enzymes, including a conserved cysteine residue at the active site and a conserved glycine residue that is activated to a free radical in this enzyme. Site-directed mutagenesis of these two conserved amino acids shows that they are also essential for the function of TutD.

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Multidisciplinary approach to management of a hereditary neurodegenerative disorder: Huntington disease

Huntington Disease is a well known autosomal dominant inherited disease resulting in emotional problems, abnormalities of movement, and eventually dementia. It stands out as one of the most devastating illnesses, not only for its neurodegenerative progression but also for its impact on families. Care often becomes fragmented due to the person's response to symptoms and/or family breakdown. The successful interaction of health care disciplines working with Huntington Disease in our centers, namely, the family physicians, nursing, Genetics, Neurology, Psychiatry, Social Work, and Long Term Care has resulted in a comprehensive program of care for our patients and their families. This article will describe the history, structure and interaction of the multidisciplinary group. It will describe the difficulties we have overcome and offer suggestions for the implementation of similar programs for the care of people with other disorders.

Carboxylation as an initial reaction in the anaerobic metabolism of naphthalene and phenanthrene by sulfidogenic consortia

The anaerobic biodegradation of naphthalene (NAP) and phenanthrene (PHE) was investigated by using sediment collected from the Arthur Kill in New York/New Jersey harbor. The initial cultures were composed of 10% sediment and 90% mineral medium containing 20 mM sulfate. Complete loss of NAP and PHE (150 to 200 muM) was observed after 150 days of incubation. Upon refeeding, NAP and PHE were utilized within 14 days. The utilization of both compounds was inhibited in the presence of 20 mM molybdate. [14C]NAP and [14C]PHE were mineralized to 14CO2. The activities could be maintained and propagated by subculturing in mineral medium. In the presence of halogenated analogs, 2-naphthoate was detected in NAP-utilizing enrichments. The mass spectrum of the derivatized 2-napththoate from the enrichment supplemented with both [13C]bicarbonate and NAP indicates the incorporation of 13CO2 into NAP. In the PHE-utilizing enrichment, a metabolite was detected by both high-pressure liquid chromatography and gas chromatography-mass spectrometry analyses. The molecular ion and fragmentation pattern of its mass spectrum indicate that it was phenanthrenecarboxylic acid. The results obtained with [13C] bicarbonate indicate that 13CO2 was incorporated into PHE. It appears, therefore, that carboxylation is an initial key reaction for the anaerobic metabolism and NAP and PHE. To our knowledge, this is the first report providing evidence for intermediates of PAH degradation under anaerobic conditions.

Southern analysis of BT-R1, the Manduca sexta gene encoding the receptor for the Cry1Ab toxin of Bacillus thuringiensis

Various subspecies of the gram-positive bacterium Bacillus thuringiensis are known to produce a wide array of insecticidal crystal proteins (ICPs) upon sporulation. These ICPs act primarily on the brush border of midgut epithelial cells of susceptible larvae. Recently, a protein of 210 kDa, isolated from the midgut of Manduca sexta, has been demonstrated to bind the Cry1Ab toxin produced by B. thuringiensis subsp, berliner and is therefore postulated to be involved in mediating the toxicity of Cry1Ab. The cDNA encoding the 210 kDa protein, termed BT-R1 (Bacillus thuringiensis receptor-1), was recently cloned, and shows limited homology to the cadherin superfamily of proteins. Quite naturally, there is a great deal of interest in the characterization of BT-R1, the gene encoding the 210 kDa Cry1Ab binding protein. The studies presented here involve the use of various restriction fragments prepared from the cDNA encoding BT-R1 as probes of Southern blots bearing M. sexta genomic DNA cleaved with a variety of restriction endonucleases. These Southern blot data reveal that there are two discrete regions within the M. sexta genome which encode sequences homologous to BT-R1. On the basis of the signal intensities seen on Southern blots, it appears that only one of these genes encodes BT-R1, whereas the other is a closely related homologue.

Management of hypercholesterolemia: practice patterns for primary care providers and cardiologists

This retrospective study, conducted as part of a private practice quality assurance process for patients with coronary artery disease (CAD), compares practice patterns in the LIFEHELP lipid clinic and non-lipid clinic settings at the Heart Institute of St. Petersburg. Quality assurance parameters included documentation of low-density lipoprotein (LDL) cholesterol, initiation of lipid-lowering therapy, and achievement of the Second National Cholesterol Education Program (NCEP II) goal for CAD patients of LDL cholesterol < or =100 mg/dL. A total of 934 patient charts with ICD-9 codes of 410-414 for ischemic heart disease were randomly selected and reviewed by a utilization review nurse. A higher level of documentation and treatment of elevated LDL cholesterol to NCEP II goal in CAD patients was found for those followed in the lipid clinic. Among non-lipid clinic physicians, cardiologists documented and treated elevated LDL cholesterol more frequently than primary care physicians. Women and the elderly subgroups received improved care in the lipid clinic setting. Screening activities and risk-factor management by cardiologists within a lipid clinic, therefore, demonstrated an improved standard of care that came closer to achieving national guidelines in the secondary prevention of CAD.

Amniotic fluid index in twin gestation

This study was performed to describe a methodology for a two-pocket amniotic fluid index (AFI) for each fetus of a twin gestation. Data included 216 pairs of measurements that were analyzed to yield regressions (curves) for all observations, as well as for the larger and smaller AFI of each observation on a particular set of twins. The twin AFI increased non-linearly until week 27. From week 27 to week 36, decreasing linear trends were found. Measures of intrasonographer, intersonographer, within-mother and between-mothers variation are reported. The estimates of variation were used to plot confidence limits for all three curves.

Microcirculation and metastasis in a new mouse mammary tumor model system

Two new metastatic mouse mammary tumor transplant lines have been established in nude mice. The Met-1 line, with the polyoma virus middle T (PyV-MT) transgene, metastasized with 100% efficiency. The Db-7 line, expressing a PyV-MT transgene mutated at positions 315 and 322, metastasized with 8.8% efficiency. Histology and computer-assisted intravital microscopy demonstrated that internal microcirculation in Met-1 was more complex than Db-7; Met-1 exhibited higher microvessel density and tortuosity (P < 0.0001). These indices of microvascular complexity correlated with the higher Met-1 metastatic rate (P < 0.0001). These two transplantable lines will be useful for investigating the complex relationship between angiogenesis and metastasis.

Clinical characteristics and management of acute stroke in patients with atrial fibrillation admitted to US university hospitals

The optimal evaluation and management of patients with atrial fibrillation who suffer an acute ischemic stroke remains controversial.

METHODS

Medical records of 171 consecutive patients with atrial fibrillation and acute stroke at six U.S. university hospitals were reviewed. Data collected included the use of antithrombotic therapy, brain and cardiac imaging, bleeding complications, stroke risk factors, and contraindications to anticoagulation.

RESULTS

Mean age was 75.4 years. Cardiovascular risk factors associated with increased stroke risk were present in 87%; 35% had at least one contraindication to anticoagulation. Half of the patients with stroke risk factors and no contraindications to anticoagulation were not receiving any antithrombotic therapy at the time of admission. Of the 22 patients who were treated with warfarin, and had INR values on admission, 16 had levels of < 2.0; only six had INR values between 2.0 and 3.0. Transthoracic echocardiography was performed in 107 patients (63%); intracardiac thrombi were visualized in only 5%. Initial brain imaging revealed hemorrhagic transformation in nine. Heparin was used in 93 patients (54%), usually within 48 hours of stroke onset. Patients who received delayed heparin typically did not have repeat brain imaging prior to starting heparin. One patient had a delayed symptomatic cerebral hemorrhage. Of the survivors, 47% were discharged and treated with warfarin (or warfarin plus aspirin), 28% with ASA, 7% with other antithrombotic therapies, and 18% with no antithrombotic therapy.

CONCLUSION

Antithrombotic therapy was underutilized and inadequately monitored in atrial fibrillation patients prior to stroke onset. After hospital admission, a wide range of diagnostic and management strategies, which often did not follow current recommendations, were employed.

Lung mesothelial cell and fibroblast responses to pleural and alveolar macrophage supernatants and to lavage fluids from crocidolite-exposed rats

An early phase of proliferation by mesothelial cells and fibroblasts occurs in the lung after asbestos deposition, but the source and identity of the cytokine(s) involved is not clear. In the present study, rats received crocidolite asbestos intratracheally and were killed at 1 and 6 wk later, animals received tritiated thymidine 1 h before death. An increase in inflammatory cells was found in bronchoalveolar and pleural lavage fluids at both times, and after 6 wk the lungs showed fibrosis which was confirmed biochemically. Asbestos fibers were found in alveolar and interstitial macrophages but not in pleural macrophages. In autoradiographs, both mesothelial cells and fibroblasts showed increased DNA synthesis at 1 wk, but only fibroblast labeling was increased at 6 wk. Lavaged macrophages from the lung (alveolar macrophages; AM) and the pleura (pleural macrophages; PLM) were cultured and supernatants tested on rat lung mesothelial cells and fibroblasts in vitro; concentrated lavaged fluids were also tested. At 1 wk, macrophages secreted growth factors for both cell types but the effect was more pronounced using lavage fluids, particularly from the pleura. The increase in fibroblast growth was reduced by an antibody to platelet-derived growth factor, but this had no effect on mesothelial cells. The growth stimulation of these cells was blocked by an antibody to keratinocyte growth factor (KGF). Using cell supernatants and lavage fluids from rats 6 wk after asbestos, growth stimulation was only observed in fibroblasts. The results suggest at least 2 cytokine effects in the lung and pleural space after asbestos exposure; one responsible for fibroblast stimulation is seen up to 6 wk later, while the other, probably involving KGF, stimulates mesothelial cell proliferation in the early response phase after a single exposure to crocidolite.

Cardiopulmonary effects of carfentanil in dama gazelles (Gazella dama)

Sixteen (10 female, six male) captive-born dama gazelles (Gazella dama) weighing 48 +/- 10 kg (mean +/- SD) were used to evaluate the cardiopulmonary effects of i.m. carfentanil and to validate the use of pulse oximetry in immobilized gazelles. Carfentanil (18.4 +/- 2.2 micrograms/kg i.m.) produced rapid induction (6 +/- 3 min), moderate muscle relaxation, and a significant (P < 0.05) decrease in heart rate (87 +/- 12 beats/min) beginning 5 min following induction and continuing throughout the immobilization period. A decrease in respiratory rates began 15 min following induction (11 +/- 4 breaths/min). Systemic hypertension was present throughout the immobilization period. Arterial blood gas analysis, performed at 10, 20, and 30 min after induction, showed PaCO2 and PaO2 values within normal limits. Arterial blood oxygen saturation (SaO2) was < 95% 10 min after induction. Relative arterial oxygen saturation (SpO2) values indicated by pulse oximetry were generally lower than SaO2 values but reliably demonstrated trends in arterial oxygen saturation as confirmed by arterial blood gas analysis. Periods of hypoxemia were usually indicated by the pulse oximeter reading and confirmed by SaO2 measurements. There was an increase in creatine phosphokinase values (88 +/- 53 U/L to 109 +/- 48 U/L) at 30 min postimmobilization. Naltrexone reversal (1.8 +/- 0.3 mg/kg, half i.v. and half s.c.) was rapid and uneventful, and time to standing was 2 +/- 1 min.

Cellular analysis of the mode of action of methyl-3,5-diiodo-4-(4'-methoxyphenoxy) benzoate (DIME) on tumor cells

The hormonally inactive methyl-3,5-diiodo-4-(4'-methoxyphenoxy) benzoate (DIME) at 1-4 mu M concentration induces morphologic changes in E-ras 20 and MDA-MB-231 and other human cancer cells such as multinucleation and enlargement and arrests the cell cycle in the M phase without affecting interphase. Time-lapse videomicroscopy allowed us to follow individual cells. Cells exposed to DIME divided in an abnormal manner, leading to 20% cell fusion and multinucleation. Chromosome painting demonstrated a large accumulation of chromosomes after 5 days of treatment with DIME, consistent with the failure of cells to divide normally. Chromosome breakage was not observed. On the other hand, highly abnormal tubulin-containing structures ensue upon exposure to DIME (1 mu M for 18 h) treatment, indicating an early biochemical action of DIME on the spindle assembly system.

Structural specificity and tumoricidal action of methyl-3,5-diiodo-4-(4'-methoxyphenoxy) benzoate (DIME)

Seventeen homologs and analogs of methyl-3,5-diiodo-4(4'-methoxyphenoxy) benzoate (DIME), a hormonally inactive analog of thyroid hormones, have been synthesized and their antitumor activity scored by assaying their antitumorigenic effect in vivo following pretreatment of E-ras 20 cells with the drug. In vivo feeding of DIME in large doses had a similar antitumor effect on human tumor xenogafts in vivo without noticeable toxicity of DIME. Inhibition of clonogenicity with MDA-MB-231 cells by DIME yielded I-50 values similar to those found in tests measuring cell growth inhibition (median I-50 less than 1.0 mu M) The apparent ultimate signal for cytocidal action of DIME is the development of dose-dependent double strand cuts of DNA. All human tumor cells so far tested, with the exception of A-549 cells (lung cancer), show high sensitivity to DIME (I-50 1.0 mu M or below). The partially refractory behavior of A-549 cells to DIME is due to the presence of an esterase that cleaves the methyl ester group of DIME. Other tumor cells have negligible esterase activity, while such activity in homogenates of normal mouse tissues is high. Cells in culture take up DIME and the magnitude of uptake parallels drug sensitivity to DIME. Extrapolation from the correlations between drug efficacy, drug uptake, esterase activity and the absence of significant in vivo toxicity of DIME point to uptake of DIME by cells in culture but not by normal cells operating in intact organs in vivo. In contrast, tumor cells in vivo take up DIME and succumb to its cytocidal action just like cells in culture.

Enhanced alveolar type II cell growth on a pulmonary extracellular matrix over fibroblasts

The growth of alveolar type II cells was studied when these cells were maintained for 2 days on a pulmonary endothelium-derived extracellular matrix (ECM) on a filter with or without lung fibroblasts in the lower chambers of culture wells. Type II cell proliferation was enhanced by the ECM compared with other substrates but was significantly higher with fibroblasts beneath. This was determined by thymidine uptake and cell numbers. The diffusing factor from fibroblasts appeared to be keratinocyte growth factor (KGF), because this cytokine increased type II cell growth in culture and the neutralizing antibody to KGF blocked the observed fibroblast-induced growth increase. None of the antibodies to various cytokines had any effect on the ECM-induced proliferation. Although the type II cells were shown to produce degradative activity for the ECM, there was little secreted enzyme activity in supernatants and there was no demonstrated autocrine-regulated growth effect. The results suggest that type II cell growth may be stimulated by both 1) a matrix-bound factor that acts through a cell contact-mediated process, and 2) a fibroblast-secreted factor that appears to be KGF.

Identification and sequence analysis of two regulatory genes involved in anaerobic toluene metabolism by strain T1

T1 is a denitrifying bacterium isolated for its ability to grow with toluene serving as the sole carbon source. Mutants of this strain that have defects in the toluene utilization pathway have been isolated and have been separated into classes based on growth phenotypes. A cosmid clone has been isolated by complementing the tutB16 (for toluene utilization) mutation. The complementing gene has been localized to a 3.3-kb DNA fragment. An additional open reading frame upstream of the tutB gene has also been identified and is designated tutC. The nucleotide sequence and the predicted amino acid translation of the 6.4-kb DNA fragment that contains these genes are presented. The tutB and tutC gene products of strain T1 have homology to members of the two-component sensor-regulator family and are proposed to play a role in the regulation of toluene metabolic genes of strain T1. To our knowledge, this is the first published report of the isolation of mutants defective in anaerobic aromatic hydrocarbon degradation. Additionally, we report for the first time the cloning of genes involved in an anaerobic aromatic hydrocarbon degradation pathway.

Molecular aspects of monogamy

Comparative studies of monogamous and nonmonogamous voles demonstrate species differences in the regional expression of oxytocin (OT) receptors in the brain. These species differences have not been observed with other neurotransmitter receptors (except vasopressin). Species differences for OT receptor distribution were also observed in other microtine and murine species selected as monogamous or promiscuous. These chemical neuroanatomic differences appear to be functionally relevant, as treatments with selective OT agonists and antagonists influence those behaviors that appear critical to pair bonding in the monogamous prairie vole. To investigate the mechanism controlling tissue-specific expression of OT receptors, we sequenced the OT receptor gene in both prairie voles and montane voles. The findings are inconclusive. Although both species differ markedly from rat and human in their regulatory (but not their coding) sequences, the species show very subtle differences from each other. Ongoing studies are investigating the consequences of these subtle differences between prairie and montane voles. At the same time, several transactivating factors that might influence OT receptor expression need to be explored. NOTE ADDED IN PROOF: The rat oxytocin receptor gene sequence, cited in FIGURES 4 and 5, was based on an error published in ref. 22. The corrected sequence has now been published (Rosen et al. 1996. Proc. Natl. Acad. Sci USA 93: 12501). The correct sequence shows greater homology with the vole oxytocin receptor gene sequences, but the remaining differences support the argument made herein for species differences in regional receptor expression.