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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 793 records · Page 44Linked to original sources
PubMed1988

Pharmacokinetics of gentamicin in cats given Escherichia coli endotoxin.

Nineteen cats were given 3 mg of gentamicin sulfate/kg of body weight by rapid IV, SC, or IM injection for baseline values. Serum concentration of gentamicin vs time data were analyzed using a noncompartmental model based on statistical moment theory. One week later, each cat was given 0.5 microgram of Escherichia coli endotoxin/kg, IV. After cats had an increase in rectal temperature of at least 1 C, 3 mg of gentamicin/kg was administered by the same route used the previous week. Serum concentration of gentamicin vs time data were analyzed, and pharmacokinetic values were compared with base-line values. For IV studies, the half-life (t1/2) of gentamicin and the mean residence time were significantly different (P less than 0.05) compared with base line, whereas the total body clearance and apparent volume of distribution at steady state were not. The harmonic mean +/- pseudo SD for the t1/2 of gentamicin after IV administration was 76.8 +/- 12.6 minutes for base line and was 65.2 +/- 12.2 minutes in the same cats given endotoxin. The t1/2 of gentamicin after SC administration was 74.6 +/- 6.2 minutes for base line and was 65.2 +/- 13.6 minutes in the same cats given endotoxin. After IM administration, the t1/2 of gentamicin was 60.3 +/- 10 minutes for base line and was 59.7 +/- 13.6 minutes in the same cats given endotoxin. After IV administration of gentamicin, the arithmetic mean +/- SD for the mean residence time was 102.4 +/- 16.1 minutes for base line vs 79.2 +/- 18.4 minutes in the same cats given endotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Pathologic changes and tissue gentamicin concentrations after intravenous gentamicin administration in clinically normal and endotoxemic cats.

Hematologic and serum biochemical values, tissue gentamicin concentrations, and renal pathologic changes were determined in clinically normal and endotoxemic cats given 3 mg of gentamicin/kg of body weight, IV. Endotoxemia was induced by IV administration of 0.5 microgram of Escherichia coli endotoxin/kg of body weight. In experiment 1, 6 cats were given endotoxin. After rectal temperature increased at least 1 degree C, cats were given gentamicin. Blood samples were collected before and at 1 and 3 hours after administration of gentamicin. With the exception of severe leukopenia, other hematologic changes or changes in serum biochemical values were not observed. In experiment 2, 24 cats were allotted to 4 groups and were given gentamicin, endotoxin, gentamicin plus endotoxin, or neither substance. Three hours later, cats were euthanatized, and tissue and body fluid specimens were obtained and were assayed for gentamicin concentration. Kidney specimens were examined microscopically. Endotoxemic cats had more gentamicin in the renal medulla than did control cats, but none of the cats had detectable renal lesions. The possible nephrotoxic synergism between gentamicin and severe endotoxemia and the lack of major differences in gentamicin concentration in extrarenal tissues indicated that the dosage of gentamicin in endotoxemic cats does not have to exceed the dosage recommended for clinically normal cats. A single dose of gentamicin administered IV did not cause renal damage in mildly endotoxemic cats, but nephrotoxicity ascribed to multiple doses of gentamicin in more severely endotoxemic cats needs to be evaluated.

Animals↗
PubMed1988

Effect of atropine on cystometry and urethral pressure profilometry in the dog.

Effects of atropine on cystometry and urethral pressure profilometry were examined in 12 healthy young adult dogs by comparing recordings obtained after xylazine alone with those obtained after administration of xylazine and atropine. Significant differences (P greater than 0.05) were not found, indicating that atropine, when administered SC with xylazine, did not markedly affect cystometrographic results and urethral pressure profiles.

Animals↗
PubMed1988

Pharmacokinetic and pathological evaluation of gentamicin in cats given a small intravenous dose repeatedly for five days.

Gentamicin was administered to six cats at a dosage of 3 mg/kg of body weight intravenously every 8 h for five days. Peak and trough serum gentamicin concentrations were measured after each injection. Gentamicin elimination rate and serum half-life were calculated. Serum urea nitrogen, creatinine, biochemistry profile, electrolyte, glucose, total protein, and albumin concentrations were measured daily. Urinalyses were performed before and after the five-day experimental period. The mean +/- SD peak serum gentamicin concentration was 7.19 +/- 1.10 micrograms/mL, and the trough concentration was 0.59 +/- 0.09 microgram/mL. These concentrations are known to be effective against most gentamicin-sensitive bacteria. The mean +/- SD gentamicin elimination rate was 0.0065 +/- 0.0004 min-1. The harmonic mean +/- pseudo standard deviation serum half-life of gentamicin was 107.21 +/- 12.79 min. There were no significant increases (P greater than 0.05) in clinicopathological variables. Microscopic examination of renal sections did not disclose pathological lesions. Signs of vestibular impairment were not observed. A dosage of 3 mg gentamicin/kg given intravenously every 8 h for five days was determined to be safe and to produce therapeutic blood levels in cats.

Animals↗
PubMed1988

Effect of levamisole on immune function and reproductive performance in first-litter gilts.

First-litter commercial cross-bred gilts were treated with levamisole (1.5, 2.5, or 3.5 mg/kg of body weight) weekly during the last 4 weeks of gestation, because similar treatment of dairy heifers had improved postpartum maternal health and neonatal survival. In the gilts, differences in reproductive performance were not found on the basis of pig survival at birth, pig survival at weaning, birth weight, or weaning weight. Also, differences between treated and control gilts were not found in response of circulating lymphocytes to mitogen stimulation (phytohemagglutinin A, concanavalin A, and pokeweed mitogen). In all gilts, the lymphocyte response to mitogen stimulation was decreased during the first week after farrowing.

Animals↗
PubMed1987

Urine estrogens and breast cancer risk factors among post-menopausal women.

Creatinine-adjusted levels of estrone, estradiol and estriol were determined in overnight urine specimens from 220 post-menopausal women, aged 54 to 66 years, from Boston (121 women) and Athens (99 women). The associations of individual and total estrogens with various characteristics of the women (age at menopause, years since menopause, parity, age at menarche, schooling, height, weight, tobacco smoking and alcohol drinking) were studied by multiple regression procedures, to explore possible relationships and evaluate their compatibility with the descriptive epidemiology of female breast cancer. Weight was consistently and significantly related to higher levels of total estrogens and of each individually; the pattern of these associations was similar in American and Greek women, suggesting that the known qualitative differences in nutrition between the two groups of women are not important modifiers of the associations between weight and estrogens. Estrogen levels in these post-menopausal women were about 40% of the corresponding follicular levels among teen-age women. They did not decrease with age. There were suggestive but non-significant negative associations between estrogen levels on the one hand, and parity and age at menarche on the other. There was no consistent association of estrogen levels with alcohol consumption. The data provide only modest support for the hypothesis that estrogens are important in breast cancer etiology.

Aged↗
PubMed1987

Heterogeneous cytogenetic abnormalities in small cell lung cancer cell lines.

Ten cell lines were established from different biopsies from nine patients with small cell lung cancer (SCLC). These were established from metastases in the marrow (7), breast (1), pleural fluid (1), and spinal cord (1) and had been in culture for periods varying from 1 to 11 months. All cell lines exhibited typical cytological features of SCLC, and produced neuron specific enolase. All lines examined (5) contained dense core granules and were tumorigenic when injected intracranially into nude mice. None of the six cell lines tested had an amplified oncogene (c-myc or n-myc) previously reported to be amplified in SCLC. Detailed chromosome analyses were undertaken and showed that a structural abnormality of chromosome 3(p11p23) was a frequent (6 of 10) but not invariable finding. Our study and one other indicate that there is not a unique chromosome abnormality present in all cases of SCLC, although loss of chromosome 13 and structural abnormalities of chromosome 3 were frequently found. A feature of these SCLC cell lines established from metastatic deposits was the complexity of the karyotypes due to numerical and structural chromosomal abnormalities.

Biopsy↗
PubMed1987

Hypoglycaemia in African children with severe malaria.

Hypoglycaemia, defined as a plasma glucose concentration below 2.2 mmol/l, developed in 15 of 47 prospectively studied Gambian children with severe chloroquine-sensitive falciparum malaria. 5 of these hypoglycaemic children died compared with 1 in the normoglycaemic group (p = 0.02). In contrast to previous observations in quinine-treated adults, in whom hypoglycaemia was associated with hyperinsulinaemia, plasma concentrations of insulin were appropriately low and plasma ketones were high. Raised plasma concentrations of lactate and alanine suggested impairment of hepatic gluconeogenesis. In African children, hypoglycaemia is an important and treatable manifestation of severe malaria and is unrelated to antimalarial treatment.

Acute Disease↗
PubMed1987

Dopaminergic cells in the caudal A13 cell group express somatostatin-like immunoreactivity.

The caudal extension of the hypothalamic A13 dopamine cell group (A13c) was studied in the rat brain with immunohistochemical techniques using antibodies raised against the dopamine synthesizing enzymes tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC). Adjacent sections revealed that the TH- and AADC-staining patterns exhibited a clear overlap with that for somatostatin (SOM). Employing a double-labelling method with SOM- and AADC-antisera and subsequent elution and restaining of the same section with TH-antiserum, it was found that all immunoreactivities occurred in the same cell bodies. This study gives the first evidence for the presence of SOM-immunoreactivity in dopamine neurons.

Animals↗
PubMed1987

The distribution of lung damage in children with cystic fibrosis and its relationship to colonisation with Pseudomonas aeruginosa.

Ventilation-perfusion lung scans were performed with 81mKr inhalation and 99mTc-albumin injection in 33 children with cystic fibrosis. It was found that both ventilation and perfusion scans yielded more information than radiographs of the chest in assessing lung damage. Using a scoring system, it was demonstrated by statistical methods that in the worst affected patients the disease was worse in the upper zones of the lungs, which changes were not detectable on chest radiographs. Pseudomonas was present in the sputum of these patients.

Adolescent↗
PubMed1987

Preoperative two-dimensional echocardiographic prediction of prosthetic aortic and mitral valve size in children.

Preoperative two-dimensional echocardiograms (2D-ECHOs) were done on 18 patients to determine the accuracy of assessing the mitral and aortic anulus diameter in children undergoing valve replacement. Fourteen patients underwent primary valve replacement and four underwent repeat valve replacement. The mean age was 11.5 years (range 2 to 17 years). The 2D-ECHO measured mitral or aortic valve anulus was compared with the external diameter of the largest prosthetic valve that could be inserted. There was a strong correlation (r = 0.99, p less than 0.001, SEE = 1.0 mm) between the 2D-ECHO measurements and the prosthetic valve size in patients undergoing primary valve replacement, but the correlation (r = 0.16, p = NS) was poor for those undergoing repeat valve replacement. In conclusion, 2D-ECHO prediction of prosthetic mitral and aortic valve size is accurate in children undergoing primary valve replacement but is poor in those undergoing repeat valve replacement.

Adolescent↗
PubMed1987

Left anterior fascicular block and masking of inferior wall infarction.

A case of inferior wall myocardial infarction that was obscured by left anterior hemiblock is presented. This report illustrates that changes in the sequence of electrical activation of the left ventricle resulting from this conduction disturbance may lead to a missed electrocardiographic diagnosis.

Electrocardiography↗