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Biomedical subjects

R Cooper

Publications and source records attributed to R Cooper.

At least 199 records · Page 11Linked to original sources
PubMed1991

Lupus nephritis. Part II. A clinicopathological correlation and study of outcome.

A 5-year retrospective study of lupus nephritis at Tygerberg Hospital was performed in an attempt to document the clinical and histological spectrum of the disease and to study the outcome of the illness. Activity and chronicity scores were used in addition to the World Health Organisation classification system. Of 55 biopsies from 51 patients reviewed, 6 were class II, 13 class III, 32 class IV and 4 class V. There were 19 deaths and in 15 of these the histological classification was IV. Renal failure and infections, often with uncommon pathogens, were the most important causes of death. Serum creatinine values and creatinine clearance at the time of biopsy or follow-up, and hypertension at follow-up showed a significant relationship with outcome. WHO class IV was associated with a poor outcome (P = 0.048) when compared with the other WHO classes combined. Activity scores showed a significant relationship to the outcome (P = 0.018). The anticardiolipin antibodies IgG and IgM were not associated with WHO class or outcome. The study revealed a spectrum of histological results similar to that of other studies, with a high mortality rate, particularly in class IV disease. Poor renal function, persistent hypertension, histological classification IV, and high activity scores were found to be important prognostic indicators.

Adolescent↗
PubMed1991

Characterization of a candidate gene for GP72, an insect stage-specific antigen of Trypanosoma cruzi.

The Trypanosoma cruzi insect stage-specific antigen GP72 was purified from epimastigotes and the amino acid sequences of peptide fragments determined. Oligonucleotides derived from these data were used to amplify and clone a cDNA sequence, which was used to isolate a full-length gene. All the sequenced peptides were encoded within the gene. The characteristics of the encoded 62,600-Da protein, including a potential amino-terminal signal sequence, a hydrophobic carboxy-terminus, and a large number of potential O-glycosylation sites, are consistent with the properties of GP72. No sequence homologies were found in searches of DNA and protein data banks. GP72 is encoded by a single pair of non-telomeric allelic genes.

Amino Acid Sequence↗
PubMed1991

The effects of the falling therapeutic and subtherapeutic barbiturate blood levels on electrocerebral silence in clinically brain-dead children.

In a retrospective study at a large children's hospital, we identified 92 children who had received barbiturates that were simultaneously discontinued at the time they were being evaluated for brain death in the presence of electrocerebral silence and clinical brain death by physical exam. Of these 92 children, 67 had barbiturate levels that were monitored from initial therapeutic or subtherapeutic levels. Repeat EEGs were obtained in 76 patients, and in all electrocerebral silence and clinical brain death (by exam) persisted despite the lower barbiturate levels. The study suggests that therapeutic and subtherapeutic barbiturate levels have no effect on the outcome of children who fulfill the criteria for brain death.

Adolescent↗
PubMed1991

Socioeconomic status and cancer survival.

Survival data from eight Cancer and Leukemia Group B (CALGB) protocols were examined for patients with lung cancer (N = 961), multiple myeloma (N = 577), gastric cancer (N = 231), pancreatic cancer (N = 174), breast cancer (N = 87), and Hodgkin's disease (N = 58). After accounting for differences in survival rate attributable to type of cancer, initial performance status, age, and 14 other protocol-specific prognostic indicators, the additional predictive value of socioeconomic status (SES) was evaluated. Race (white v non-white) was not a significant predictor of survival time, but income and education were. People with lower annual incomes (below $5,000 per year in the years 1977 to 1981) and those with lower educational level (grade school only) showed survival times significantly shorter than those with higher income or education, respectively. These survival differences were associated with, but could not be fully explained by, severity of disease at initial presentation. SES continued to exert a small but significant impact on cancer survival, even after controlling for all known prognostic variables. Economically and educationally disadvantaged cancer patients may require treatment programs that include education about treatment and compliance, even after an initial diagnosis is made and treatment is initiated. Because SES is related to survival independent of all known prognostic variables, it should be included in the data bases of clinical trial groups to provide a more accurate test of the effectiveness of new therapies.

Adolescent↗
PubMed1991

Elevated pulmonary artery pressure. An independent predictor of mortality.

Analyses in this study were based on hemodynamic and angiographic data obtained in a cohort of 1,371 predominantly black patients during right and left heart catheterization. All patients were followed up prospectively for a mean of 117 weeks, and 103 fatal events were recorded. In Cox survival analysis, three variables were found to be independently related to survival: pulmonary artery mean pressure (PAMP), number of stenosed vessels, and left ventricular (LV) ejection fraction (p less than 0.01); in multivariate stepwise analysis, PAMP entered the model first with the largest chi 2 value of the three prognostic variables (chi 2 = 33.4; p less than 0.0001). The PAMP was 32 percent higher in decedents compared with survivors (25 + 11 mm Hg vs 19 + 8 mm Hg, p less than 0.01 [mean, SD]) and a 10 mm Hg increase in PAMP was associated with a more than fourfold increase in the relative risk of dying; this finding was independent of pulmonary vascular resistance and therefore could not be attributed to primary pulmonary vascular or parenchymal disease. In both the subgroup of 1,118 patients with a normal LV ejection fraction (greater than 50 percent) and the 253 patients with a reduced ejection fraction (less than 50 percent), PAMP emerged as an independent predictor of mortality (p less than 0.0001 and 0.01, respectively), and is therefore a marker of cardiac disease beyond impairment of systolic contractile function. Among patients without obstructive coronary artery disease, PAMP alone provided prognostic information in the multivariate survival analysis.

Black People↗
PubMed1991

Blood pressure and educational level among factory workers in Ibadan, Nigeria.

An epidemiological survey of blood pressure was carried out among men employed at a single factory in Ibadan, Nigeria. All available employees participated, with only four persons excluded at the time of analysis for missing data. Hypertension was uncommon (blood pressure greater than or equal to 160/95 = 8%) and little rise in mean blood pressure was observed with age. Obesity was likewise uncommon, although body mass index was related to blood pressure (r = 0.22; P less than 0.01). Contrary to reports from Western industrialised countries, education was found to have a significant positive association with blood pressure, and this finding was independent of age, body mass index, pulse, and alcohol consumption. The process of modernisation is associated with rising blood pressure in West Africa at the present time, but the absolute risk remains low.

Adolescent↗
PubMed1991

Rett syndrome.

Explore the source record for details and available documents.

Carbon Dioxide↗
PubMed1990

Parvovirus B19-induced perturbation of human megakaryocytopoiesis in vitro.

Parvovirus B19 infection leads to transient aplastic crises in individuals with chronic hemolytic anemias or immunodeficiency states. An additional unexplained sequela of B19 infection is thrombocytopenia. Because B19 is known to have a remarkable tropism for human erythropoietic elements, and is not known to replicate in nonerythroid cells, the etiology of this thrombocytopenia is uncertain. We sought to define the pathobiology of B19-associated thrombocytopenia by examining the role of B19 on in vitro megakaryocytopoiesis. B19 infection of normal human bone marrow cells significantly suppressed megakaryocyte (MK) colony formation compared with mock-infected cells. No such inhibition was observed with a nonpathogenic human parvovirus, the adeno-associated virus 2 (AAV). The B19-MK cell interaction was also studied at the molecular level. Whereas low-density bone marrow cells containing erythroid precursor cells supported B19 DNA replication, no viral DNA replication was observed in B19-infected MK-enriched fractions as determined by the presence of viral DNA replicative intermediates on Southern blots. However, analysis of total cytoplasmic RNA isolated from B19-infected MK fractions showed a low-level expression of the B19 genome as detected by quantitative RNA dot blots as well as by Northern analysis. Furthermore, a frame-shift mutation in a recombinant AAV-B19 hybrid genome segment that encodes the viral nonstructural (NS1) protein significantly reduced the observed inhibition of MK colony formation. These studies indicate tissue-tropism of B19 beyond the erythroid progenitor cell, and lend support to the hypothesis that B19 genome expression may be toxic to cell populations that are nonpermissive for viral DNA replication.

Blotting, Northern↗
PubMed1990

Care is the key.

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Appointments and Schedules↗
PubMed1990

Characterization of peptidyl-nucleoside antifungal antibiotics from fermentation broth.

Characterization of sinefungin related antifungal antibiotics from fermentation broth was accomplished by coupling photodiode array (PDA) detection to high performance liquid chromatography (HPLC). From the combined HPLC-PDA evaluation of broth filtrate, we detected five sinefungin related components. Fast atom bombardment (FAB) mass spectroscopic evaluations, mass-analysed ion kinetic energy spectra (MIKES) and collision activated (CA) MIKES of these components confirmed their respective identities. Our findings from the combination of HPLC photodiode array acquisition and FAB-mass spectrometry suggest we have detected the presence of a previously unreported sinefungin analogue.

Adenosine↗
PubMed1990

Single papillary muscle and ostium primum defect.

Parachute mitral valve (single papillary muscle) is commonly associated with complete atrioventricular (AV) canal. We report a case of ostium primum defect associated with single papillary muscle.

Echocardiography, Doppler↗
PubMed1990

Changes of slow and steady brain potentials during complex tasks.

Recordings of slow potentials and changes of steady level of the EEG in man during manual and mental tasks show that an increase in mental load (as determined by the difficulty of the task) is accompanied by an increase in negativity at midline electrodes. It is suggested that this negativity is due to cortical excitation that facilitates performance.

Electroencephalography↗
PubMed1990

Carbendazim-induced alterations of reproductive development and function in the rat and hamster.

We are developing a data base that will allow us to select endpoints that would be useful in the detection of reproductive toxicity in a multigenerational test. In this effort, carbendazim (MBC), a known reproductive toxicant, was administered to male and female rats from weaning, through puberty, gestation, and lactation. A similar study was conducted with hamsters. In rats, MBC was administered at 0, 50, 100, 200, or 400 mg/kg/day. Hamsters were dosed at 0 or 400 mg/kg/day. In the parent (P0) generation, landmarks of puberty were measured. In females, estrous cyclicity, litter size, the number of implants, organ weights, and histology were assessed. Our assessment of the male rat included organ weights, testicular and epididymal sperm counts, a quantitative measure of sperm motility, sperm morphology, testicular histology, and endocrine measures. The growth, viability, and reproductive function of the offspring (F1) were observed during a 4-month period of continuous breeding. In the P0 of both species. MBC did not alter pubertal development, growth, or viability. The reproductive potential of the rats treated with MBC at 200 and 400 mg/kg/day was reduced due to effects on sperm production and fetal viability. In the male rat, MBC treatment markedly altered sperm morphology, testicular and epididymal weights, and sperm numbers and testicular histology. Fertility, sperm motility, and hormonal levels were altered, primarily in the males with very low sperm counts. The ability to conceive did not appear to involve a female factor. In P0 female rats, MBC administration caused postimplantation losses in the high-dosage groups and a few malformed rat pups were found in the litters from the 100 and 200 treatment groups. MBC was less toxic to the hamster than the rat. The only reproductive effects induced by MBC treatment were on sperm measures. Fertility of the P0 generation and fetal and neonatal (F1) viability were not decreased by MBC administration. In the male rat, testis weight, sperm numbers in the cauda epididymis and testis and sperm morphology were sensitive to the effects of MBC. In females, counting implantation scars at necropsy was useful, as this information allowed us to confirm pregnancy and identify postimplantation losses induced by MBC administration.

Animals↗
PubMed1990

Survival determinants in black patients with angiographically defined coronary artery disease.

Long-term survival of blacks with angiographically defined coronary artery disease was examined in a series of 1233 consecutive patients who underwent cardiac catheterization at a large urban municipal hospital. Vital status information was available at a mean of 86 weeks for the cohort as a whole, and 94 deaths were recorded. As noted in other angiographic series that included blacks, a high proportion of patients in this study had unobstructed coronary arteries (41%), and there was a preponderance of women (56%). Hypertension was present in 82% of the cases, whereas 68% of the sample had left ventricular hypertrophy as revealed by echocardiogram. The cumulative proportion of patients who were surviving at 5 years was 90 +/- 1 (+/- SEM), 79 +/- 4, and 70 +/- 4 for patients with no obstructive lesions, one-vessel disease, and multivessel disease, respectively. The survival rate at 3 years for patients who had undergone bypass surgery (N = 152) was only 82% (+/- 5%). Noninvasive univariate predictors of mortality included male sex, history of myocardial infarction, Q waves on electrocardiogram, exercise duration on treadmill stress testing, and left ventricular hypertrophy. Angiographic predictors included left ventricular end-diastolic pressure, the number of diseased coronary vessels, ejection fraction, and mean pulmonary artery pressure. Regression analysis showed an independent association for all the angiographic variables noted previously as well as for echocardiographically determined left ventricular hypertrophy. Survival rates for blacks with coronary artery disease in this series were considerably lower than those currently reported for whites, particularly for patients who underwent coronary bypass grafting.(ABSTRACT TRUNCATED AT 250 WORDS)

Black or African American↗
PubMed1990

Correlation of electroencephalogram, respiration and movement in the Rett syndrome.

Day time video records of 14 girls with the Rett syndrome (RS) (6-17, mean 7 years) were analysed to correlate episodic abnormalities in respiration, movement and electroencephalograms (EEG). Records were compared with those of 12 healthy girls (6-18, median 14 years) who hyperventilated voluntarily. Three RS girls (6-7 years) had minimal respiratory dysrhythmia and showed no correlation between EEG respiration and movement. The other 11 RS girls (6-17 years) had severe awake respiratory dysrhythmia; 10 showing hyperventilation (with hypocapnia) which alternated with active expiratory apnoeic pauses and one with the latter only. All had periods of awake regular breathing with normal respiratory gases. In these girls EEG showed non-epileptic generalised slow activity some of which was paroxysmal. In the six youngest (6-10 years) of these 11 RS girls, non-epileptic paroxysms of EEG slow activity at 1 1/2-4 Hz occurred and were associated with periods of normal breathing and normal pCO2 levels whether girls were alert, drowsy or asleep, but were uncommon during episodes of hyperventilation (and hypocapnia). In four of these girls the EEG paroxysms occupied less than or equal to 1-3% of the time during periods of respiratory dysrhythmia (81 minutes) and 8-100% of the time during alert periods with normal breathing (29 minutes), p less than or equal to 0.001 for this difference. Short bursts of EEG slowing occasionally followed prolonged apnoeic pauses. In two cases brief partial complex seizures occurred. In five of these girls stereotypic movements exacerbated during episodes of respiratory dysrhythmia and reduced during normal breathing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

The nature of pre-operative anxiety.

In a study of 247 patients who had general anaesthesia for dental procedures, the incidence of individual anxieties was noted using a questionnaire completed by the patient. The most common anxieties related to the period before transfer to the operating theatre, intra-operative awareness and postoperative pain. These anxieties were present in over half the patients questioned. The follow-up questionnaire was completed by 207 patients in order to indicate which anxieties they would expect to have if they needed anaesthesia in the future. All anxieties were less frequent than found before operation.

Adult↗