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Biomedical subjects

H Taylor

Publications and source records attributed to H Taylor.

At least 91 records · Page 5Linked to original sources
PubMed1993

A comparison of immunoglobulin G-containing high-molecular-weight complexes isolated from children with juvenile rheumatoid arthritis and congenital human immunodeficiency virus infection.

Circulating immune complexes have been described in both juvenile rheumatoid arthritis and in AIDS. We isolated high-molecular-weight complexes from plasma of children with juvenile rheumatoid arthritis and congenital human immunodeficiency virus infection by sequential gel filtration followed by affinity chromatography on protein A-Sepharose. We demonstrate that 1) mixed IgG-, IgM-, and IgA-bearing immune complexes can be found in both juvenile rheumatoid arthritis and congenital human immunodeficiency virus infection and 2) complexes isolated via affinity chromatography on protein A-Sepharose do not have detectable C4 but activate the classic complement pathway in vitro.

Adolescent↗
PubMed1993

Intracerebral hematoma related to thrombolysis for myocardial infarction.

The incidence of intracerebral hematomas after myocardial infarction increases after thrombolysis. As noted in the case described, clots formed after the administration of thrombolytic agents may remain liquid, and this blood can be drained by a catheter. However, in this case, the patient continued to bleed locally. This problem requires the development of methods to stop such ongoing local bleeding. It may be prevented in the future by improved thrombolytic drugs.

Aged↗
PubMed1993

Measuring progression of lens opacities for longitudinal studies.

A number of classifications schemes for the grading of lens opacities have been developed but none of them have been examined for reliability and validity in prospective or longitudinal studies. The purpose of this study was to develop and test a method for determining progression which was sufficiently sensitive to true change and insensitive to measurement error. The method consists of assessing various sources of measurement error, determining the likely magnitude of the error, and setting boundaries for changes in opacification which incorporate this error. Measurement error was assessed in 203 nuclear lens photographs graded using a decimal system and 136 cortical lens photographs graded in 1/16th area. 95% confidence intervals were calculated of the distribution of differences between photographs and graders and the width of this intervals defined as measurement error. The magnitude of the measurement error was +/- 0.7 units for nuclear opacities and +/- 2/16 for cortical opacities. The utility of this approach was tested in a series of 84 clinic patients followed at irregular intervals for up to 3 years. Only one eye showed "improvement" and progression rates ranged from 1.8 to 5.5% for nuclear opacities and 0 to 7.4% for cortical opacities in this clinic-based series. This approach appears to be useful for discarding noise and enabling the assessment of progression for use in longitudinal studies.

Cataract↗
PubMed1993

Rose Questionnaire responses among black and white inpatients admitted for coronary heart disease: findings from the Birmingham-BHS Project.

Evidence of higher coronary heart disease mortality rates among blacks than among whites raises questions concerning differences in health care-seeking for heart disease between blacks and whites. As part of a larger project evaluating health care-seeking behavior for coronary heart disease, we interviewed hospitalized patients who had diagnoses of coronary artery disease, ischemic heart disease, chest pain, or myocardial infarction, or who were admitted to rule out myocardial infarction. The sample included 1140 white men, 347 black men, 574 white women, and 355 black women. The interview included demographic information, usual care, access to usual care, and chest pain items. Demographic and medical care access differences emerged between African-American and white participants. We also compared the prevalence of Rose Questionnaire angina between blacks and whites. Among patients who scored positively for Rose angina, black men reported more recent onset of their angina and fewer episodes during the past 6 months compared to all other groups, and they sought medical care less often compared with white men. Multiple logistic regression analyses suggest that African-American respondents were less likely to score positively for Rose angina and were less likely to seek treatment for their symptoms among those who had angina, when controlled for demographic, risk factor, and access to care variables. Blacks and whites in our sample also differed in factors associated with scoring positive for angina and seeking medical care for their symptoms, among those who reported angina. We interpret these findings as suggesting that promoting routine usual care among whites may be an important approach for increasing care-seeking for coronary heart disease symptoms. For blacks, improved coronary heart disease case identification and/or educational approaches to promote greater awareness of symptoms and of the need for seeking treatment for symptoms may be important to increase the likelihood that they will seek medical care for their symptoms.

Black or African American↗
PubMed1993

Complement activation and immune complexes in juvenile rheumatoid arthritis.

We investigated the potential role of the complement system in juvenile rheumatoid arthritis (JRA) by examining plasma for levels of complement activation fragments C4d and Bb. We correlated findings with both disease activity and laboratory abnormalities, including immune complex (IC) levels. While there was a strong correlation between active disease and both C4d and Bb plasma levels in JRA, no strong correlations could be made between IC levels and complement activation products; weak associations were seen between complement activation fragments and erythrocyte sedimentation rate. Our data suggest that plasma complement activation is a concomitant of active disease in JRA; however, its role in the pathophysiology of JRA remains uncertain.

Antigen-Antibody Complex↗
PubMed1992

The uninsured and the debate over the repeal of the Massachusetts universal health care law.

OBJECTIVES: The debate in Massachusetts over the repeal of the first state-based "pay or play" universal health plan is discussed using data from a survey of 1066 Massachusetts households. The survey attempted to measure the problems of the uninsured, to estimate the likelihood that they would buy insurance if offered, and to calculate the proportion of the uninsured who would be covered under an employer mandate. DESIGN: A survey conducted in person and by telephone in 1066 households, with an oversample of uninsured households, using stratification, clustering, disproportionate sampling, and poststatistical weighting. PARTICIPANTS: Adults aged 18 years and older who were knowledgeable about the insurance status of persons in their household. MAIN OUTCOME MEASURES: Insurance status, employment status, access to and use of health services, and willingness to purchase health insurance. RESULTS: First, the present system of hospital-based uncompensated care in Massachusetts is inadequate by itself to meet the needs of uninsured residents. Uninsured persons are less likely than insured ones to seek medical care for chronic health problems and serious symptoms requiring evaluation. Second, 83% of uninsured families and 24% of uninsured individual respondents would purchase one of several insurance options with 30% of the cost subsidized. Last, the employer mandate provisions of the legislation would cover 43% of the uninsured in Massachusetts. CONCLUSION: In the current economic climate, the political viability of the universal health care plan and similar national initiatives is uncertain given the intractable conflict between perceptions of the financial stability of small businesses that do not offer insurance and the health care needs of uninsured individuals.

Cluster Analysis↗
PubMed1992

Cloning and structural analysis of the human c-kit gene.

The recent identification of the mouse White spotting and Steel loci as genes encoding the c-kit receptor and its ligand, respectively, has shed light on the importance of this ligand and receptor in embryogenesis, melanogenesis and hematopoiesis. In order to determine if the c-kit proto-oncogene is involved in human disease, we isolated seven overlapping lambda recombinants, using a fetal brain cDNA, and characterized the normal human gene (KIT). The longest mapped transcript is 5230 bp, is alternatively spliced and includes 21 exons that span more than 70 kb of DNA. From the exon-intron structure, we have localized an alternative splice site to the 3' end of exon 9. The overall c-kit gene structure closely resembles that found in the CSF-1R gene (c-fms). This similarity includes a large first intron, the same number of exons containing translated sequence and very similar exon-intron boundaries. Using pulsed-field gel electrophoresis, we have linked KIT to the platelet-derived growth factor receptor A gene, with both residing on a 700-kb BssHI fragment. These data will allow investigation into the control of KIT expression and the potential to identify mutations or altered expression of this gene in human disease.

Base Sequence↗
PubMed1992

Indirect effect of guanine nucleotides on antagonist binding to A1 adenosine receptors: occupation of cryptic binding sites by endogenous vesicular adenosine.

Guanine nucleotides such as guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) have been found to increase the binding of antagonists to adenosine A1 receptors. This response can be attributed either to a direct effect of GTP on receptors to increase antagonist affinity or to an indirect effect to decrease the affinity of receptors for a pool of endogenous adenosine that cannot be readily removed from membranes. In this study, adenosine content was measured in preparations of membranes and 3-[(3-cholamidopropyl)dimethylamino]-1-propanesulfonate (CHAPS)-solubilized receptors by a sensitive radioimmunoassay. In both preparations, pools of adenosine (2.5-10 pmol/mg of protein) were detected that were resistant to deamination by added adenosine deaminase (0.5-3 units/ml) unless membrane lipids were first dissolved in acetone. Electron microscopic examination of crude CHAPS-solubilized receptors revealed the existence of small vesicles (< 1 microns in diameter). Furthermore, most "solubilized" receptors were retained by a 0.1-microns filter. The effects of GTP gamma S were evaluated on the binding of an antagonist, 3-(4-amino-3-125I-phenethyl)-1-propyl-8-cyclopentylxanthine (125I-BW-A844U), to A1 receptors of bovine brain membranes, receptors solubilized in CHAPS (crude solubilized), or receptors partially co-purified with G proteins by agonist affinity chromatography (partially purified). GTP gamma S (10 microM) increased antagonist binding to membranes (20-50%) and crude CHAPS-solubilized receptors (> 200%) but increased binding to partially purified receptors by only 10-15%. GTP gamma S decreased agonist (125I-N6-aminobenzyladenosine) binding and increased antagonist Bmax, but did not significantly decrease (5%) the dissociation rate of the antagonist. Omission of Mg2+ mimicked the effects of GTP gamma S on agonist and antagonist binding and increased both the association and dissociation rates of 125I-BW-A844U. These data suggest that a Mg(2+)-dependent GTP gamma S-induced increase in antagonist binding to membranes and solubilized receptors is primarily due to unmasking of cryptic binding sites occupied by contaminating vesicular adenosine. These findings are consistent with the observation that adenosine receptor antagonists have been found to have little or no inverse agonist physiological effects in well oxygenated tissues.

Adenosine↗
PubMed1991

Discrete subpopulations, defined by CD45 isoforms, coexist within the leukaemic cells of B-chronic lymphocytic leukaemia patients.

The expression of CD45 isoforms by B-CLL leukaemic lymphocytes has been analysed by 2 colour flow cytometry and vectorial iodination. The cytometry has demonstrated the presence of cells with different CD45 phenotypes which vary in the relative expression of the CD45RA and CD45RO determinants. Discrete populations have been detected which can coexist within an individual patient. One of these populations which is CD45RO-negative consists of cells expressing only the 230 kD isoform, in the others the smaller isoforms are expressed, the appearance of the CD45RO determinant of 180 kD being accompanied by the appearance of the 190 kD isoform. The relative proportion of cell populations is stable within patients but can be altered by phorbol ester which enhances CD45RO expression and diminishes CD45RA expression. The populations may be partially resolved by the density gradient fractionation.

Antigens, CD↗
PubMed1991

Hemoglobin Columbia Missouri or alpha 2[88 (F9) Ala----Val]beta 2: a new high-oxygen-affinity hemoglobin that causes erythrocytosis.

A previously undescribed hemoglobin variant, hemoglobin Columbia Missouri, alpha 88 (F9) Ala----Val, was detected in a 22-year-old white man who was undergoing assessment for erythrocytosis. This new hemoglobin variant does not separate from hemoglobin A by electrophoresis in conventional media, by isoelectric focusing, or by electrophoresis of purified globin chains in 8 M urea. It exhibits a high oxygen affinity, with a P50 (oxygen tension at 50% saturation) of 19.3 torr for the patient's whole blood. The substitution of hemoglobin Columbia Missouri is an internal residue near the end of the F helix of the alpha chain. Hemoglobin Okazaki has an arginyl residue substitution for a cysteinyl residue at F9 (beta 93) in the beta chain. In comparison with hemoglobin Okazaki, the substitution in hemoglobin Columbia Missouri has a more pronounced effect on oxygen affinity. Consequently, hemoglobin Columbia Missouri is associated with erythrocytosis, whereas hemoglobin Okazaki is not.

Adolescent↗
PubMed1991

Does the system fit?

A new poll shows an American social ethic similar to other people's. So why is our health-care system so different?

Attitude to Health↗