Biomedical subjects

L M Thompson

Publications and source records attributed to L M Thompson.

At least 37 records · Page 2Linked to original sources

PubMed1992

Clinical presentation and outcome of patients with HIV infection and tuberculosis caused by multiple-drug-resistant bacilli.

OBJECTIVE: To determine the clinical manifestations of patients with human immunodeficiency virus (HIV) infection and tuberculosis caused by multiple-drug-resistant bacilli compared with those with single-drug-resistant or susceptible bacilli. DESIGN: Descriptive, case-control, and cohort studies. SETTING: A large urban teaching hospital. PATIENTS: Sixty-two patients with tuberculosis caused by multiple-drug-resistant bacilli (cases) and 55 patients with tuberculosis caused by single-drug-resistant or susceptible bacilli (controls). MEASUREMENTS: Characteristics of clinical presentation, radiographs, pathologic abnormalities, antituberculosis treatment, and clinical course. RESULTS: Twenty cases (32%) had concomitant pulmonary and extrapulmonary disease at presentation compared with 9 controls (16%; odds ratio, 2.4; 95% CI, 1.0 to 5.9). More cases had alveolar infiltrates (76%; odds ratio, 3.6; CI, 1.2 to 11.4), interstitial infiltrates with a reticular pattern (67%; odds ratio, 7.8; CI, 1.0 to 83.5), and cavitations (18%; odds ratio, 6.6; CI, 0.8 to 315.3) on initial chest radiographs compared with controls (49%, 19%, and 3%, respectively). Pathologic specimens from cases showed extensive necrosis, poor granuloma formation, marked inflammatory changes with a predominance of neutrophils, and abundant acid-fast bacilli. Twenty-five cases received two or more effective antituberculosis drugs for more than 2 months. Only 2 cases had three consecutive negative cultures for Mycobacterium tuberculosis; one patient died within 1 day of the last negative culture, and the other had positive cultures 496 days later. The remaining 23 cases had persistently or intermittently positive cultures despite therapy. The clinical course of these cases suggested overwhelming miliary tuberculosis with involvement of the lungs (77%), pleura (15%), stool (34%), meninges (13%), bone marrow (16%), blood (10%), lymph nodes (10%), and skin (8%). The median survival time was 2.1 months for cases compared with 14.6 months for controls (P = 0.001, log-rank test). CONCLUSIONS: Tuberculosis caused by multiple-drug-resistant bacilli in patients with HIV infection is associated with widely disseminated disease, poor treatment response with an inability to eradicate the organism, and substantial mortality.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Indeterminate western blot patterns in a cohort of individuals at high risk for human immunodeficiency virus (HIV-1) exposure.

Our objective was to map serial patterns of Western blot reactivity over time of a cohort of initially ELISA-negative, Western blot-indeterminate individuals from a high-risk group and to determine if these individuals were at increased risk of harboring occult HIV-1 infection. A 2-year prospective study used serial ELISA, two types of Western blot, immunologic profiles, HIV-1 culture, and analysis by polymerase chain reaction. Subjects were 20 ELISA-negative, Western blot indeterminate homosexual volunteers and 20 matched seronegative controls. Results showed that 19 of 20 study subjects completed a mean of 17.0 months of clinical and laboratory follow-up. Reactivities with p24 and/or with p55 were the two most commonly observed Western blot patterns, occurring in 70% of individuals. Specific Western blot reactivity was dependent upon the particular immunoblot preparation being used and varied considerably on a longitudinal basis. No individual pattern appeared predictive of an increased likelihood of subsequent seroconversion to HIV-1 relative to controls. By all other criteria including polymerase chain reaction analysis, samples from 17 of 19 individuals remained negative for HIV-1 at each time point. Two individuals evolved from an indeterminate to a positive Western blot and, simultaneously, from a negative to a positive polymerase chain reaction analysis, during follow-up. Our conclusions were as follows. ELISA-negative, Western blot-indeterminate individuals from a high-risk group show marked variability in immunoblot findings over time, and these patterns do not appear predictive of an increased likelihood of infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

Neuroendocrine aspects of primary endogenous depression: XII. Receiver operating characteristic and kappa analyses of serum and urine cortisol measures in patients and matched controls.

The majority of studies investigating the diagnostic utility of hypothalamo-pituitary-adrenal (HPA) axis measures in major depression have focused on the dexamethasone (DEX) suppression test (DST). The DST correlates well, but imperfectly, with other measures of HPA activity. Fewer studies have considered the ability of basal cortisol measures to discriminate depressives from non-depressed patients or normal subjects. We used receiver operating characteristic (ROC) analysis to examine the mean 24-hr serum cortisol concentration, our benchmark of basal HPA axis activity, compared to smaller segments of the 24-hr cortisol profile, post-DEX serum cortisol values, and pre- and post-DEX 24-hr urinary free cortisol (UFC) levels in 40 primary endogenous major depressives compared to 40 matched normal control subjects. No statistically significant differences in ROC curves were found between mean 24-hr cortisol and the other cortisol measures. The mean 24-hr, 1300h-1600h, 1600h-1900h, and 16-hr post-DEX serum cortisol concentrations and the post-DEX UFC level all appeared to be comparable estimators of HPA activity. The single 2300h pre-DEX serum cortisol concentration and the pre-DEX 24-hr UFC level performed notably poorer than did the other measures. We additionally calculated kappa statistics to determine the optimally sensitive and specific discriminators of the cortisol measures between the depressives and the normal controls. The 2300h post-DEX serum cortisol measure was optimally sensitive, and the 1500h post-DEX serum cortisol was optimally specific. The 0700h, 1500h, and 2300h post-DEX serum cortisols were very close together as the optimally efficient measures (best combination of sensitivity and specificity).

Adult↗

PubMed1992

A recombination event that redefines the Huntington disease region.

We report both a recombination event that places the Huntington disease gene proximal to the marker D4S98 and an extended linkage-disequilibrium study that uses this marker and confirms the existence of disequilibrium between it and the HD locus. We also report the cloning of other sequences in the region around D4S98, including a new polymorphic marker R10 and conserved sequences that identify a gene in the region of interest.

Chromosomes, Human, Pair 4↗

PubMed1992

Contractual arrangements between residency programs and HMOs.

BACKGROUND: Although one out of seven health maintenance organizations (HMOs) is directly involved in graduate medical education (GME), either as an accredited sponsoring organization or through a contractual agreement with an academic medical center or teaching hospital to serve as an ambulatory rotation site, relatively little is known about the extent to which HMOs have provider contracts with faculty or residents of GME programs. Such provider contracts are not agreements to collaborate on the education of residents, but rather contractual arrangements under which individual physicians or groups (who happen to be residents or faculty) agree to provide services to HMO enrollees in return for some form of compensation. METHODS: In 1990, the Group Health Association of America conducted a survey of a sample of residency training programs in family medicine, internal medicine, and pediatrics to ascertain the extent to which (1) residents and faculty of residency training programs are participating physicians in HMOs; and (2) HMO enrollees are serving as the patient base for GME in ambulatory settings. RESULTS: Overall, 42% of the residency program respondents indicated that they contract with HMOs to provide services to enrollees. Nearly two thirds (64%) of family practice programs have provider contracts as compared with 28% of pediatrics programs and 24% of internal medicine programs. Provider contracts with independent practice associations are by far the most common, followed by group, network, and staff model contracts, in that order. CONCLUSIONS: It is apparent that provider contractual arrangements between HMOs and primary care residency programs are quite common, especially in the area of family practice. These contractual arrangements have probably resulted in a more predictable and stable patient revenue base for residency programs. The long-term effects on provider practice styles and the financing of graduate medical education are less clear.

Contract Services↗

PubMed1991

A rare insertional translocation of proximal segment with heterochromatic region of 1q into 7p in monozygotic twins and spontaneous abortions.

We present a family identified through a healthy 20-year-old female with a history of multiple successive spontaneous abortions. Her karyotype demonstrates a rare balanced insertional translocation between chromosomes 1 and 7, 46,XX,dir ins(7;1)(p15.3;q12q21.3). This is the first reported case of a 7;1 insertional translocation involving the proximal segment of chromosome 1 and may well be the cause of the multiple spontaneous abortions in our proband.

Abortion, Spontaneous↗

PubMed1991

A gene encoding a fibroblast growth factor receptor isolated from the Huntington disease gene region of human chromosome 4.

The gene responsible for Huntington disease (HD), an autosomal dominant neurodegenerative disorder, is located near the terminus of the short arm of chromosome 4. Detailed genetic linkage and physical mapping studies have defined a region of approximately 2.5 million basepairs where the disease gene is likely to be located. Efforts to identify the disease gene are now focused on the identification and characterization of expressed genes in this region. Nucleotide sequence analysis of a cDNA clone derived from the HD gene region has revealed that it encodes a member of the fibroblast growth factor subfamily of tyrosine kinase receptors, some members of which are known to be involved in the differentiation and survival of certain cell types within the central nervous system. Histochemical analysis using in situ hybridization revealed its expression in many areas of the brain, among them being the caudate and putamen. The nature of this gene, FGFR3, and its map location make it a possible candidate for the HD gene.

Amino Acid Sequence↗

PubMed1991

Involvement of health maintenance organizations in graduate medical education.

Prepaid health care plans are likely to play an important part in the current transition from inpatient to ambulatory care training of physicians, because such plans enroll one in seven Americans. In the spring of 1990, the Group Health Association of America conducted a survey of health maintenance organizations (HMOs) to assess their level of involvement in graduate medical education (GME). A questionnaire was sent to the 481 HMOs in the United States that had been operational for at least four years; 58% responded. Fifteen percent (42 HMOs) indicated that they were directly involved in GME. The majority of these 42 indicated that they had an agreement with an academic medical center (AMC) or a teaching hospital to serve as an ambulatory care rotation site. About one-sixth of the 42 HMOs had been approved by the Accreditation Council for Graduate Medical Education to serve as a sponsoring organization. HMOs directly involved in GME were more likely to be staff model and group model HMOs; older plans with an enrollment of 50,000 or more; not-for-profit plans; and those owned or sponsored by an AMC.

Academic Medical Centers↗

PubMed1990

Effects of increasing doses of beta-agonists on airway and parenchymal hysteresis.

We examined the effects of a deep inhalation on airway caliber before and after increasing doses of a beta-agonist in eight subjects, including one former and two current but mild asthmatics. With bronchodilation the increase in maximal flow on the partial flow-volume curve (P), initiated from functional residual capacity, exceeded that seen on the maximal curve (M), initiated from total lung capacity, such that isovolumic maximal flows diminished after a deep inhalation; i.e., M/P ratios fell with bronchodilation, as we and others have found. Five of eight reversed this downward trend in M/P ratios at higher cumulative doses. Quasistatic pressure-volume curves (QSPV) were simultaneously performed on two of these five and demonstrated a decrease in pressure-volume hysteresis (PVH) at the higher doses associated with a rising M/P ratio. Three of eight had continuing low and diminishing M/P ratio up to the highest dose given. QSPV were performed in two of these three and indicated no change in PVH at any of the doses. One of these two had a repeat study using a subcutaneous beta-agonist after the inhaled drug was given, and the M/P ratio rose as QSPV PVH fell. These data support the relative hysteresis analysis of airway and parenchyma as an explanation for volume history effects on airway caliber.

Administration, Inhalation↗

PubMed1989

Dispensable presequence for cellular localization and function of mitochondrial malate dehydrogenase from Saccharomyces cerevisiae.

The nucleotide sequence corresponding to codons for the 17-amino acid residues in the presumed targeting presequence for yeast mitochondrial malate dehydrogenase was removed by oligonucleotide-directed mutagenesis of the isolated gene (MDH1). Integrative transformation was used to insert the "leaderless" gene (mdhl-) into the MDH1 chromosomal locus of a strain containing a disrupted MDH1 gene. Expression of the mature form of malate dehydrogenase as a primary translation product was verified by demonstrating that the mature form is synthesized in mdhl- cells at the same rate as the precursor form in MDH1 cells in the presence of carbonyl cyanide m-chlorophenylhydrazone and by comparison of in vitro translation products of RNAs from mdhl- and MDH1 cells. Expression of mdhl- restores total cellular malate dehydrogenase activity to levels comparable to those in wild type cells and reverses the phenotype associated with strains containing MDH1 disruptions by restoring wild type rates of growth in media containing acetate as a carbon source. Immunochemical analyses and enzyme assays show comparable levels of malate dehydrogenase in the matrix fractions from mitochondria isolated from mdhl- and MDH1 cells and give no evidence for accumulation of the mature enzyme in the cytosol of mdhl- cells. These results indicate that the presequence for malate dehydrogenase is not essential for efficient mitochondrial localization or function in yeast.

Amino Acid Sequence↗

PubMed1989

Integrated proviral human immunodeficiency virus type 1 is present in CD4+ peripheral blood lymphocytes in healthy seropositive individuals.

Evidence of a latent human immunodeficiency virus type 1 (HIV-1) infection in healthy, seropositive individuals who do not have viral antigens in their sera and from whom virions cannot be rescued in cocultivation experiments was examined. Proviral DNA was detected by amplification by the polymerase chain reaction procedure. In each of 10 seropositive individuals, the presence of HIV-1 proviral sequences was demonstrated in their peripheral blood mononuclear cells. By using fluorescence-activated cell sorting, we obtained highly enriched subpopulations of peripheral blood mononuclear cells and found that the CD4+ T-cell subset is the cell subset that consistently harbors the HIV-1 proviral sequences. The number of HIV-1-infected CD4+ T cells was variable among the 10 healthy individuals, ranging from 1 in 100 to 1 in 40,000. While in vitro infection of CD4+ T cells causes down regulation and eventual loss of CD4 surface molecules, this is not true in vivo where it is only the CD4+ population that harbors the virus. This disparity may reflect differences between a latent infection in vivo with the lytic response of cells infected in vitro.

Antibodies, Monoclonal↗

PubMed1989

Effects of lung volume, volume history, and methacholine on lung tissue viscance.

We examined the effects of lung volume change and volume history on lung resistance (RL) and its components before and during induced constriction. Eleven subjects, including three current and four former asthmatics, were studied. RL, airway resistance (Raw), and, by subtraction, tissue viscance (Vtis) were measured at different lung volumes before and after a deep inhalation and were repeated after methacholine (MCh) aerosols up to maximal levels of constriction. Vtis, which average 9% of RL at base line, was unchanged by MCh and was not changed after deep inhalation but increased directly with lung volume. MCh aerosols induced constriction by increasing Raw, which was reversed by deep inhalation in inverse proportion to responsiveness. such that the more responsive subjects reversed less after a deep breath. Responsiveness correlated directly with the degree of maximal constriction, as more responsive subjects constricted to a greater degree. These results indicate that in humans Vtis comprises a small fraction of overall RL, which is clearly volume-dependent but unchanged by MCh-induced constriction and unrelated to the degree of responsiveness of the subject.

Adult↗

PubMed1988

Gene sequence and primary structure of mitochondrial malate dehydrogenase from Saccharomyces cerevisiae.

The nucleotide sequence was determined for a 1.5-kilobase genomic fragment containing the mitochondrial malate dehydrogenase gene (MDH1) of Saccharomyces cerevisiae. The open-reading frame encodes a precursor form of the mature enzyme containing an amino-terminal extension of 17 amino acid residues. In vitro translation experiments confirm that the initial translation product of MDH1 is larger than the mature polypeptide. Transcription of MDH1 initiates at several sites from 83 to 97 nucleotides 5' of the translational start site. Alignment of the amino acid sequence for the mature yeast enzyme with those for mammalian mitochondrial and for Escherichia coli malate dehydrogenases reveals polypeptides of very similar sizes with identical amino acids at 54% and 48% of the residue positions, respectively. The amino acid sequences of the yeast and mammalian mitochondrial targeting sequences are similar but less related than the mature polypeptides. The yeast MDH1 gene is shown to reside on chromosome XI.

Amino Acid Sequence↗

PubMed1988

Evaluation of six new 99mTc-IDA agents for hepatobiliary imaging.

IDA derivatives of three substituted benzothiazol, and two substituted chlorophenyl and one substituted pyrazoline compounds have been labeled with 99mTc and screened with four rat models with hepatocellular dysfunction manifesting varying degrees of change of liver architecture and hepatocellular damage associated with an active parenchymal destruction, fatty metamorphosis and cirrhosis. Organ distribution studies at 1 h postinjection have been compared in normal and diseased animal models for each agent labeled with 99mTc and with 99mTc-Disofenin (Disida) and Lidofenin (Hida) and 131I-Rose Bengal. From the data obtained with the six new IDA derivatives, the distribution kinetics of 99mTc-Arclophenin, (N-N'-2-benzoyl-4-chlorophenyl)carbamoylmethyl) imino diacetic acid (Phenida), are closely comparable to 99mTc-Disofenin in all animal models. Crossover patient studies (n = 14) for clinical evaluation of 99mTc-Arclophenin vs 99mTc-Disofenin indicate the close similarity of the 2 agents with regard to blood pool retention, gross liver/heart ratios and liver washout, suggesting Arclofenin as a suitable agent for hepatobiliary function studies. The impaired hepatocellular animal models presented should serve for fast screening of hepatobiliary agents and enable comparison of a series of closely related compounds.

Adult↗

PubMed1988

Cytogenetic studies of renal cell carcinoma.

To examine the possibility that patients with renal cell carcinoma (RCC) have chromosomal abnormalities at a common gene locus, we undertook a study of patients with and without a history of hereditary disease as part of an ongoing population-based case-control study of risk factors in RCC. We identified 112 patients for cytogenetic study. Chromosome preparations were made from peripheral blood cultures with standard and giemsa (GTG) banding techniques. C-banding was used to determine C-polymorphism. Eighty-nine cases had completely normal male and female karyotypes. Twenty-seven of them had C-polymorphism. In 16 patients, random numerical and structural abnormalities were observed. In the remaining seven patients, four had mosaic karyotypes, and the other three showed structural abnormalities. There was no statistically significant difference in the frequency of the abnormal karyotypes between the hereditary and nonhereditary RCC patients. This concludes a negative cytogenetic study of RCC patients that failed to show any constitutional rearrangement in blood cells.

Adolescent↗

PubMed1988

Out on a limb.

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Allied Health Personnel↗

PubMed1987

Dealing with AIDS and fear: would you accept cookies from an AIDS patient?

Acquired immunodeficiency syndrome (AIDS) has engendered a crisis of fear among the public and health professionals alike. In addition to the myriad anxieties that generally accompany dying and death, AIDS patients must deal with numerous additional fears. In rushing to treat the physiologic aspects of AIDS, health professionals have generally failed to provide adequate support systems to deal with the emotional needs of dying AIDS patients. Health professionals must now move rapidly to develop support systems based on a realistic understanding of the fears and the other powerful emotions confronted by AIDS victims. Such systems must permit AIDS patients to give meaning to their adversity.

Acquired Immunodeficiency Syndrome↗

PubMed1987

Isolation and expression of the gene encoding yeast mitochondrial malate dehydrogenase.

The mitochondrial tricarboxylic acid cycle enzyme malate dehydrogenase was purified from Saccharomyces cerevisiae, and an antibody to the purified enzyme was obtained in rabbits. Immunoscreening of a yeast genomic DNA library cloned into a lambda gt11 expression vector with anti-malate dehydrogenase immunoglobulin G resulted in identification of a lambda recombinant encoding an immunoreactive beta-galactosidase fusion protein. The yeast DNA portion of the coding region for the fusion protein translates into an amino acid sequence which is very similar to carboxy-terminal sequences of malate dehydrogenases from other organisms. In s. cerevisiae transformed with a multicopy plasmid carrying the complete malate dehydrogenase gene, the specific activity and immunoreactivity of the mitochondrial isozyme are increased by eightfold. Expression of both the chromosomal and plasmid-borne genes is repressed by growth on glucose. Disruption of the chromosomal malate dehydrogenase gene in haploid S. cerevisiae produces mutants unable to grow on acetate and impaired in growth on glycerol plus lactate as carbon sources.

Amino Acid Sequence↗