Quantitation of plasma oxidatively modified low density lipoprotein by sandwich enzyme linked immunosorbent assay.
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Adult↗
Biomedical subjects
G Chang
Publications and source records attributed to G Chang.
HIV-1 proviral genotypes from the peripheral blood mononuclear cells of an infected patient are differentially represented in expressed sequences.
The RNA genome of the human immunodeficiency virus type 1 (HIV-1) is established as proviral DNA in infected cells. Only some of these cells may actively produce the array of viral RNAs that support progeny virion production. In vivo expression of a subset of proviral genotypes could influence the experimental characterization of the viral quasispecies. We have explored the relationship between DNA and cDNA genotypes of the envelope gene by the molecular cloning and nucleotide sequencing of these templates from noncultivated peripheral blood mononuclear cells from an HIV-1-infected patient. Eleven proviral DNA and nine cDNA clones representing the V1-V3 region of gp120 were recovered and sequenced. The proviral group was more heterogeneous than the cDNA group by nucleotide sequence changes and V1 length polymorphisms. Deduced amino acid sequences from this data set showed that the two groups were distinct in primary structure, in the position of N-linked glycosylation sites, and in the net charge of the V3 loop. The V1-V2 region discriminated between the groups more strongly than the V3 region. The differential representation of HIV-1 envelope genotypes in the cDNA versus the proviral compartment may have important implications for the pathogenesis of disease and for the design of antiviral therapeutics.
Amino Acid Sequence↗
Characterization of the murine macrophage mannose receptor: demonstration that the downregulation of receptor expression mediated by interferon-gamma occurs at the level of transcription.
The macrophage mannose receptor (MMR) is a 175-Kd cell-surface transmembrane glycoprotein that is expressed on tissue macrophages where it functions both to mediate the uptake of mannose-rich glycoproteins and as a phagocytic receptor for bacteria, yeasts, and other pathogenic microorganisms. In this report we describe the cloning of the full-length cDNA of the mouse macrophage mannose receptor and we investigate the level at which interferon gamma (IFN-gamma) downregulates mannose receptor expression. The latter is a marker of the functional state of the cell as high levels are expressed on resident and inflammatory macrophages, whereas cells activated by treatment with IFN-gamma have decreased-to-absent cell-surface mannose receptor expression. The murine MMR cDNA contains an open reading frame that predicts a protein of 1,456 amino acids. Transient expression of the protein in heterologous cells shows that this cDNA encodes a functional mannose receptor. The deduced amino acid sequence of this protein has an overall 82% homology with the human mannose receptor and as such, the ectodomain contains an N-terminus that is cysteine-rich followed by a fibronectin type II domain and eight carbohydrate recognition domains (CRDs). The ectodomain is linked to a hydrophobic transmembrane region and a 46-amino acid cytoplasmic tail. All of the eight CRDs are particularly well conserved, especially CRD4, which shows 92% homology with the equivalent region of the human protein. Steady-state levels of murine MMR mRNA were measured in the macrophage cell line J774E, which is known to express the protein at the cell surface. These levels were decreased by a 4- to 8-hour incubation with IFN-gamma, but were almost abolished by overnight treatment with this cytokine. Nuclear run-on experiments showed that IFN-gamma inhibits MMR gene transcription. Therefore, the regulation of mannose receptor expression by IFN-gamma provides a novel system in which to study the mechanisms by which this cytokine represses gene expression.
Amino Acid Sequence↗
Naltrexone and coping skills therapy for alcohol dependence. A controlled study.
Ninety-seven alcohol-dependent patients were treated for 12 weeks in a double-blind, placebo-controlled study evaluating naltrexone and two manual guided psychotherapies in the treatment of alcohol dependence. Patients were randomized to receive either naltrexone or placebo and either coping skills/relapse prevention therapy or a supportive therapy designed to support the patient's own efforts at abstinence without teaching specific coping skills. Naltrexone proved superior to placebo in measures of drinking and alcohol-related problems, including abstention rates, number of drinking days, relapse, and severity of alcohol-related problems. Medication interacted with the type of psychotherapy received. The cumulative rate of abstinence was highest for patients treated with naltrexone and supportive therapy. For those patients who initiated drinking, however, patients who received naltrexone and coping skills therapy were the least likely to relapse.
Adaptation, Psychological↗
Systemic phospholipase A2 and cachectin levels in adult respiratory distress syndrome and multiple-organ failure.
In this clinical study we have prospectively measured plasma phospholipase A2 (PLA2) activity and tumor necrosis factor (TNF) levels in ventilated intensive care unit (ICU) patients with (n = 9) and without (n = 12) evidence of respiratory distress syndrome (ARDS) and multiple-organ failure (MOF). The median peak TNF concentration in control patients was 40 ng/L (range less than 40-100 ng/L) and in ARDS patients 231 ng/L (range 100-2550 ng/L; p less than 0.001). All of the control patients were discharged alive from the ICU, whereas 6 of 9 ARDS patients died in the ICU. In 6 ARDS patients, it was possible to measure more than 4 consecutive plasma TNF levels. Of these 6 patients, the 3 with persistent elevations in systemic TNF above 230 ng/L succumbed (p less than 0.05, one-tailed). Patients with ARDS also had parallel elevations in plasma PLA2 activity above controls. These elevations were significant for arterial PLA2 activity but not for venous PLA2 activity. Our study suggests that serial measurement of plasma (arterial or venous) TNF levels may have (1) prognostic and (2) etiologic significance in ICU patients with ARDS and MOF.
Critical Care↗
Improving treatment outcome in pregnant opiate-dependent women.
Outcomes for 6 pregnant methadone-maintained opiate-dependent subjects in enhanced treatment were compared to those of 6 women receiving conventional methadone maintenance. Enhanced treatment consisted of weekly prenatal care, relapse prevention groups, thrice weekly urine toxicology screening with positive contingency awards for abstinence, and therapeutic child care during treatment visits in addition to treatment as usual. Treatment as usual included daily methadone, group counseling, and random urine toxicology screening. Study patients differed from the comparison group in three important ways, having fewer urine toxicology screens positive for illicit substances (59% vs. 76%), three times as many prenatal visits (8.8 vs. 2.7), and heavier infants (median birth weight, 2959 vs. 2344 grams). These results suggest that enhanced drug treatment can improve pregnancy outcome and, in particular, reduce low birth weight for this high-risk population.
Adult↗
Reporting alcohol-impaired drivers: results from a national survey of emergency physicians.
STUDY OBJECTIVE: The purpose of this exploratory study was to learn of physicians' opinions on mandatory reporting of alcohol-impaired drivers they encounter in the course of their clinical work to the police or authorities from the Division of Motor Vehicles. DESIGN AND PARTICIPANTS: Two thousand four hundred sixty-four physicians randomly selected from the American College of Emergency Physicians were sent an anonymous, one-time only, self-administered questionnaire seeking demographic information and assessing attitudes toward mandatory reporting and alcohol treatment. MEASUREMENTS AND MAIN RESULTS: One thousand fifty-five physicians returned the survey. Seventy-eight percent of respondents agreed with mandatory reporting. More than half expressed strong agreement. Through canonical discriminant analysis we are able to identify the complex factors influencing attitude toward mandatory reporting. CONCLUSION: Although our preliminary results must be interpreted with caution, it appears that with the appropriate legal safeguards, physicians are supportive of mandatory reporting of the alcohol-impaired driver encountered in the course of clinical work.
Adult↗
Phospholipid peroxidation deacylation and remodeling in postischemic skeletal muscle.
Reperfusion of ischemic skeletal muscle is associated with white blood cell (WBC) sequestration and hydroperoxy-conjugated diene (HCF) formation, a marker of free radical-mediated phospholipid peroxidation. The purpose of this study was to define the kinetics of phospholipid fatty acyl peroxidation, deacylation, and remodeling in postischemic skeletal muscle during prolonged reperfusion in vivo, and to determine whether reperfusion with WBC and plasma-depleted blood would attenuate postischemic phospholipid peroxidation and myocyte necrosis. The isolated, paired, canine gracilis muscle model was used. After 5 h of ischemia, muscles underwent unaltered reperfusion or initial reperfusion with WBC-deficient blood cells resuspended in hydroxyethyl starch, followed by return to normal circulation (modified reperfusion). The concentration of native fatty acids and HCDs of linoleic acid extracted from muscle phospholipids was quantified by gas chromatography and positively identified by mass spectrometry. Ischemia and reperfusion resulted in phospholipid deacylation and a selective increase in phospholipid stearic acid content, but had no effect on total phospholipid phosphorus. Modified reperfusion decreased 1) early HCD formation (54%) and 2) postischemic skeletal muscle necrosis (49%). These data suggest that reperfusion results in phospholipid deacylation and remodeling, and that the initial oxidant stress during reperfusion may be a significant determinant of ultimate muscle necrosis.
Acylation↗
A clinically applicable method for long-term salvage of postischemic skeletal muscle.
The clinical significance and applicability of interventions aimed at reducing reperfusion injury in postischemic skeletal muscle remain unproven, since long-term muscle salvage has not been demonstrated by most treatment protocols that attenuate early reperfusion injury. We have shown that reperfusion of ischemic skeletal muscle results in an early and prolonged sequestration of white blood cells and activation of the alternative complement cascade. The purpose of this study was to determine if 40 minutes of reperfusion with blood depleted of white blood cells and complement proteins, followed by 2 days of normal perfusion, would reduce muscle necrosis after 5 hours of ischemia. The isolated paired canine gracilis muscle model was used. The treatment muscle was initially reperfused with arterial blood that had been spun, washed, passed through a leukocyte removal filter, and resuspended in hydroxyethyl starch (greater than 99.9% removal of white blood cells and the complement proteins factor B and C4). The contralateral control muscle was subjected to unaltered reperfusion. Blood flow (ml/min/100 gm) was measured by timed collection of gracilis venous blood. Myeloperoxidase activity (absorbance at 655 nm/min/mg tissue protein) in muscle biopsies was used to monitor white blood cell sequestration. After 48 hours of reperfusion in vivo, necrosis was quantified by nitroblue tetrazolium staining. Initial reperfusion with white blood cell and complement depleted blood significantly reduced muscle necrosis (53% +/- 3% vs 29% +/- 8%, p less than 0.0025, paired t test). Early blood flow was improved, (p = 0.0025, repeated measure-ANOVA), but subsequent white blood cell sequestration was not altered (p = 0.33, repeated measure-ANOVA). This suggests that a significant amount of white blood cell mediated injury occurs during the first 40 minutes of reperfusion. Preventing early complement activation and white blood cell mediated reperfusion injury is an intervention that is feasible during surgery and may result in clinically significant salvage of postischemic skeletal muscle.
Animals↗
Factors predicting inpatient length of stay in a CMHC.
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Adult↗
Lifetime psychiatric illness and premenstrual syndromes.
The frequency of affective symptoms in most descriptions of premenstrual syndromes (PMS) suggests a potential etiologic link between menstrually-related mood changes and specific psychiatric disorders. The purpose of this study is to assess women presenting with "PMS" for lifetime psychiatric illness and PMS, according to rigorous diagnostic criteria comparable to those for "late luteal phase disorder," a proposed DSM-III-R diagnosis requiring further study. The women were interviewed with the Schedule for Affective Disorders and Schizophrenia Lifetime Version (SADS-L) and they kept prospective records of menstrual symptoms with the Moos Menstrual Distress Questionnaire - Form T (Moos MDQ-T). Of the 20 women evaluated, 85% had lifetime psychiatric illness and 30% had PMS. Careful psychiatric assessment is recommended in patients presenting with "PMS" as their chief complaint.
Adult↗
Astemizole-induced paresthesia.
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Astemizole↗
Mutational analysis of the C-terminus of human interferon-gamma.
We have developed an expression/mutagenesis system and a series of screening procedures for the study of structure-function relationships in human interferon-gamma (HuIFN-gamma). Here we report a preliminary evaluation of the C-terminal portion of the molecule. An expression vector, p652trp gamma, was constructed which includes (i) the HuIFN-gamma gene under control of the trp promoter, (ii) elements controlling replication of both single- and double-stranded versions of the vector DNA; and (iii) the ampicillin resistance gene. (Other vectors using these same elements were constructed but proved to be unsatisfactory, being characterized by a rapid decline, as cells containing them were passaged, in their potential to achieve high expression levels.) A mutagenesis cassette was constructed by introduction of unique restriction sites flanking the nucleotides encoding the C-terminal 23 amino acids, and this cassette was replaced with chemically synthesized, degenerate oligonucleotides by ligation. Colonies from cells transformed with the reconstructed vector were stored in LB glycerol in microtiter plates, and these were screened by hybridization with synthetic oligonucleotides. Plates were grown in minimal medium to express the encoded interferon and lysed by an efficient, mild procedure. A polyclonal antibody specific for the C-terminal four amino acids of HuIFN-gamma was used to establish that the lysis procedure preserved the C-terminus, and to score for frame shift and nonsense mutations. Immunochemical assays also were used, with mixed results, to quantify IFN-gamma concentration in the lysate. An antiviral assay was employed to assess biological activity. Over 1000 isolates were screened and clones with properties representative of various classes of phenotypes were further characterized, in some cases after partial purification from the lysate. Three types of mutations were isolated: point mutations, nonsense mutations and frame shift mutations. The results from each type of mutation confirm earlier observations of the important role of basic residues in the 128-131 region of the molecule for biological activity. At the same time, the results suggest that most residues within the cassette can be altered without significant effects on biological activity. These results are discussed in the context of several possible mechanisms.
Amino Acid Sequence↗
Mutational analysis of the C-terminus of human gamma-interferon.
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Amino Acid Sequence↗
The emergency department surveillance of alcohol intoxication after motor vehicle accidents.
To assess the surveillance of alcohol intoxication by surgical house staff, we examined the charts of 346 motor vehicle accident patients who presented to the trauma center of an urban teaching hospital emergency department. Half of the charts were reviewed before and half were reviewed after June 1986, when Connecticut enacted PA86-345, a law changing court rules of evidence so that the analysis by a hospital of a patient's blood could be used to establish probable cause for driving while under the influence of an intoxicant. We predicted and found no change in house-staff practice after passage of the law, since information about intoxication was obtained for immediate treatment. The rate of testing remained constant at 25%, with the median alcohol concentration at 200 mg/dL. Not one patient was referred for alcohol abuse evaluation or treatment. We recommend more vigorous attempts to evaluate, diagnose, and refer patients who abuse alcohol since they threaten the public health.
Accidents, Traffic↗
Physicians' recognition of psychiatric disorders in children and adolescents.
We examined the ability of physicians to recognize psychiatric and behavioral problems in the children and adolescents under their care. The report by 35 physicians of psychopathology in their patients was compared with the reports of parents and of children which were derived from direct and independent assessments of the children and of parents about their children. Physicians' reports of psychological problems were also compared with reports by a child psychiatrist who used all available data on the children and made a best estimate diagnosis. Agreement between the physicians and any of the three other sources of information--parents, children, or child psychiatrist--was poor, with kappa ranging from -15 to .11. Physicians tended to underreport both minor and serious psychiatric problems in children. These results are discussed in the context of the recent American Medical Association initiative to improve the health of children and adolescents.
Adolescent↗
Physical and hydrodynamic factors affecting erythrocyte adhesion to polymer surfaces.
Using a flow cell design which ensures fully developed laminar flow, the influence of various hydrodynamic and physical factors in determining the extent of erythrocyte adhesion to various polymer surfaces has been examined. Specifically we have investigated the effect of exposure time, flow rate, erythrocyte concentration, and substrate surface tension on the extent of erythrocyte adhesion. The results indicate: (1) the extent of erythrocyte adhesion is most extensive on the more hydrophobic surfaces; (2) the rate of adhesion is higher on the more hydrophobic surfaces; (3) saturation coverage occurs after 7-10 min of exposure to the erythrocyte suspension for all substrates examined. No "lag-time" in the onset of adhesion was observed; (4) The level of saturation depends on the bulk erythrocyte concentration, increasing with increasing cell concentration; (5) the extent of adhesion decreases with an increase in flow rate; and (6) substrate surface defects such as roughness have a major effect on the pattern of erythrocyte adhesion.
Biocompatible Materials↗
Endothelialization of polymer surfaces.
The role that substrate surface properties play in influencing the extent of endothelialization of polymer surfaces has been investigated. For a wide range of polymer surfaces, the degree of endothelialization for both porcine and bovine endothelial cells is directly related to polymer surface tension: increased endothelialization occurring with increasing substrate surface tension. As a result of adsorption of the proteins in the culture media, the surface properties of the polymers are altered considerably. The protein-coated polymers were characterized by means of liquid-liquid contact angle measurements under non-denaturing conditions. A striking correlation is observed between the degree of endothelialization and the measured dextran contact angle. The degree of endothelial cell spreading is not related to polymer surface tension. Cell morphology and extracellular matrix production, however, are influenced by substrate surface properties.
Adsorption↗