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Biomedical subjects

J Brown

Publications and source records attributed to J Brown.

At least 901 records · Page 50Linked to original sources
PubMed1985

Correlation of tissue infection and serologic findings in pigs fed Toxoplasma gondii oocysts.

Each of thirteen 6-week-old pigs was inoculated per os with 10,000 sporulated oocysts of Toxoplasma gondii. By postinoculation day (PID) 13, pigs were seropositive by the indirect fluorescent antibody test. Beginning on PID 13 and every 7 days thereafter through PID 97, 1 pig was killed and 6 tissues were examined for T gondii. Of the 13 pigs, 11 were infected, including the 1st pig killed on PID 13, although none of the pigs had gross lesions of toxoplasmosis. Tissues harboring T gondii most frequently were the heart and brain; organisms were detected less frequently in the longissimus muscles, diaphragm, and liver. Toxoplasma gondii was not detected in the bronchial lymph nodes. There was good correlation between antibody and presence of T gondii in these pigs. One additional pig, maintained as a noninfected control, remained seronegative and had no evidence of infection when killed on PID 97.

Animals↗
PubMed1985

Effects of heterologous antineutrophil antibody in the cat.

Rabbit anti-cat neutrophil serum was injected intraperitoneally into cats to study its effects on blood neutrophil numbers, on development of neutrophils in bone marrow, and on the fate of circulating and developing neutrophils. There was a significant difference (P less than 0.05) in curves of blood neutrophil numbers between antineutrophil serum (ANS)- and normal rabbit serum (NRS)-injected cats; neutrophil counts tended to decrease in ANS-injected cats, whereas a transient increase in counts occurred in NRS-injected cats. Significant left shifts (P less than 0.05) were present in ANS-injected cats, but absent in NRS-injected cats. Toxic morphologic changes were noted in blood neutrophils in all ANS-injected cats. Significant bone marrow changes (P less than 0.05) occurred in ANS-injected cats, but were absent in NRS-injected cats. Myelocyte percentages of the granulocyte marrow population increased during the time that segmented neutrophil percentages decreased. In ANS-injected cats, the percentage of cells in the mitotic pool (myeloblasts, promyelocytes, myelocytes) significantly increased (P less than 0.05), with a corresponding significant decrease (P less than 0.05) in the postmitotic pool (metamyelocytes, bands, segmented neutrophils). Aspirated bone marrow smears (Wright's stain) revealed marrow macrophages containing phagocytized neutrophil bands and segmented neutrophils. Sections of liver obtained after cats were necropsied revealed neutrophil phagocytosis by Kupffer's cells, but neutrophil phagocytosis was not demonstrated in other tissues examined.

Agranulocytosis↗
PubMed1984

Intravenous chelated gadolinium as a contrast agent in NMR imaging of cerebral tumours.

NMR imaging was performed on 12 patients with cerebral tumour before and after administration of intravenous gadolinium diethylene triamine penta-acetic acid (DTPA) (0.1 mmol/kg). Contrast enhancement was seen in all cases. Ring enhancement was most frequent (7 cases) but central, linear, patchy, and diffuse enhancement were also seen with both inversion-recovery and spin-echo sequences. The degree of enhancement was greater than that seen with X-ray computed tomography (CT) in 8 cases, equal to it in 3 cases, and less in 1 case. NMR distinguished between tumour and peritumoral oedema to the same extent as did CT. No side-effects were encountered and there was no significant change in urea, creatinine and electrolytes, liver function tests, blood coagulation, or urine testing after administration of gadolinium-DTPA. Gadolinium-DTPA is likely to be of considerable value in NMR imaging of the brain.

Adult↗
PubMed1984

Angiotensin II receptors in chromatin fragments generated by micrococcal nuclease.

Rat liver nuclei were digested with micrococcal nuclease following incubation with 125I-angiotensin II (AII) or with 125I-AII and excess unlabeled hormone. Chromatin enriched in 125I was solubilized after 3 min and was applied to a BIO-GEL A-5 M column. Labeled hormone was 40-60% displaceable by unlabeled hormone, in nucleoprotein eluting with a V/Vo near 1.9, indicating that these solubilized chromatin fragments contained specific receptors for AII. Furthermore, a discrete AII binding nucleoprotein particle was resolved on DNP gel electrophoresis. Additionally, binding to specific AII nuclear receptors appeared to bring about changes in chromatin structure consistent with the induction of transcriptional activity.

Angiotensin II↗
PubMed1984

The effect of westernization on urine estrogens, frequency of ovulation, and breast cancer risk. A study of ethnic Chinese women in the Orient and the USA.

In a 10-year incidence survey of breast cancer in the City of Boston, 14 cases in American Chinese women were observed, while approximately 13 were expected on the basis of age-specific incidence in the white population. In Hawaii, on the other hand, while breast cancer incidence rates for ethnic Chinese are approximately three times as high as those of indigenous Chinese populations, data indicate that they are still 35% lower than those of whites in Hawaii or on the US mainland. We have compared estrogen concentrations in the urine of Chinese women in the Orient, Honolulu, and Boston. Levels of estrone (E1) and estradiol (E2) increased greatly from the low to the high risk group. The increase was evident among both the younger (15-19 years) and the older (20-24 years) women, in both follicular and luteal phase specimens. The crude unweighted average increase from Oriental to continental US Chinese was about 38% and 34% for E1 and E2, respectively. On the other hand, levels of E3 decreased from the low-risk to the high-risk group, but the decrease was modest (16%) and not always regular. There were no systematic or significant differences in the frequency of ovulation in the three groups of women. These results are compatible with the hypothesis that high levels of estrone and estradiol are important to breast carcinogenesis. Whether E3 has some additional "protective" effect or is irrelevant is unclear. The data do not support the hypothesis that total urine estrogens (E1 + E2 + E3) are predictive of population groups at high risk for breast cancer and they appear inconsistent with the hypothesis that frequency of ovulation (or anovulation) is an important aspect of breast carcinogenesis.

Adolescent↗
PubMed1984

Hemodynamic and pulmonary studies in pulmonary alveolar microlithiasis.

A 34-year-old woman with biopsy-proved pulmonary alveolar microlithiasis is described. Cardiac catheterization data and results of pulmonary function studies are presented. Mild to moderate pulmonary hypertension occurred with supine leg exercise, possibly reflecting a reduced capacity of the vascular bed evident only with increased pulmonary blood flow and tachycardia. Attention should be paid to the level of physical activity in patients with this disease, particularly if the vital capacity is reduced below 80 percent of that predicted.

Adult↗
PubMed1984

Amplification by macrophages of prostaglandin-mediated immunosuppression in mice bearing syngeneic tumors.

The role of macrophages in tumor-mediated immunosuppression was examined, using C57B1/6 strain mice bearing four different immunosuppressive transplantable syngeneic tumors (Lewis Lung Carcinoma, B16 Melanoma, and two fibrosarcomas induced by methylcholanthrene in our laboratory). When tested for immunosuppressive activity, in inhibiting the induction of antibody formation by normal spleen cells in response to SRBC in vitro, the splenic and peritoneal macrophages from tumor-bearing mice were all significantly suppressive. The degree of suppression correlated with immunosuppression in tumor-bearing mice challenged in vivo with SRBC. Direct action of tumor cells on normal splenic macrophages in vitro caused them to become suppressive, the extent of suppression dependent on the time of interaction and on the immunosuppressive activity of the tumor cells in vivo. Pretreatment of suppressive splenic macrophages with indomethacin, a potent inhibitor of the synthesis of prostaglandins (PG), reduced significantly their immunosuppressive activity. Also, peritoneal macrophages from tumor-bearing mice produced significantly more PGE in culture than control macrophages. Thus, tumor-activated macrophages, presumably those macrophages that infiltrate the tumor in a host reaction against the tumor, serve to amplify the level of immunosuppression in the host by producing relatively large amounts of PGE that is a key physiological mediator in the activation and function of suppressor T lymphocytes. The stimulation of PGE synthesis in macrophages, as a result of their interaction with syngeneic tumors, is initiated by PGE produced in relatively large amount by the tumor cells.

Animals↗
PubMed1984

Pre-exposure rabies prophylaxis: efficacy of a new packaging and delivery system for intradermal administration of human diploid cell vaccine.

The efficacy of a newly designed syringe prepacked with human diploid cell vaccine in a sufficient quantity to deliver individual 0.1 ml doses intradermally was tested by injecting 40 veterinary students with a single dose on each of days 0, 7 and 28. A second group of 20 students received the ordinary series of three 1.0 ml intramuscular vaccine doses by needle and syringe. All participants in both groups developed neutralizing antibodies to rabies above the suggested minimum of 0.5 international units per ml by day 49. The geometric mean titres were somewhat lower in the group receiving the 0.1 ml doses compared to the group given 1.0 ml doses; however, this was considered of no clinical significance since everyone achieved a titre above the suggested minimum. There was little difficulty in reconstituting the vaccine prepacked in the lumen of the syringe and the syringe was easy to manipulate.

Adult↗
PubMed1984

The effects of benzodiazepines on hormones in women with idiopathic hirsutism.

A single blind study was planned to investigate whether benzodiapines would reduce androgens in women with idiopathic hirsutism. Placebo was given for the first month followed by four months of a benzodiazepine (chlorazepate 15 mg nocte or diazepam 10 mg nocte ). Plasma samples were collected during the follicular and luteal phases of each therapy month. Hair growth was assessed monthly. Eighteen women concluded the five months of the trial of whom ten received chlorazepate and eight diazepam. Comparison of follicular plasma samples during the placebo phase and fourth month of benzodiazepine found a significant increase in sex hormone binding globulin and a significant decrease in dehydroepiandrosterone sulphate with benzodiazepine therapy. No significant effects on hair growth were observed. A longer therapy time may be needed to demonstrate effects of benzodiapines on hirsutism. Further studies are needed to determine whether benzodiazepines affect hormonal parameters in normal men and women.

Adult↗
PubMed1984

Lateral asymmetry of positive and negative emotions.

This reaction time study examined whether the left and right hemispheres are differentially specialized to process positive and negative affect respectively in adult females and males. Either happy or sad facial expressions of emotion were presented simultaneously with neutral facial expressions to the two visual fields. Happy faces were responded to more rapidly in the left visual field-right hemisphere with no visual field differences for sad faces. Females were superior to males when emotional facial stimuli were presented to the left visual field and were more accurate in recognizing sad faces compared to happy ones.

Adult↗
PubMed1984

Effect of variation of in vitro culture techniques upon oocyte fertilization and embryo development in human in vitro fertilization procedures.

Human in vitro fertilization requires a safe healthy environment for gamete interaction. This report compares the use of tube cultures with that of organ culture dishes for human in vitro fertilization procedures. Moreover, an oocyte grading system is described that provides an individualized approach for timing of insemination. From the results of this study, the use of organ culture dishes and variable oocyte preincubation demonstrates a significant improvement in human fertilization success in vitro.

Culture Media↗
PubMed1984

Correlation of inhibin and follicle regulatory protein activities with follicular fluid steroid levels in anovulatory patients.

Follicular fluid was obtained from anovulatory patients (n = 12), stimulated with human menopausal gonadotropin, clomiphene, and human chorionic gonadotropin to evaluate the relative responses of inhibin, follicle regulatory protein, and steroid levels in follicles from ovaries requiring exogenous stimulation for follicular development. Follicular fluid concentrations of estradiol, progesterone, androstenedione, testosterone, dihydrotestosterone, and 3 alpha-androstenediol were determined by radioimmunoassay. Follicular fluid inhibin activity was determined by suppression of rat pituicyte follicle-stimulating hormone, and follicle regulatory protein activity was determined by suppression of porcine granulosa cell aromatase. The mean level of steroids were progesterone (7529 +/- 1601 ng/ml), estradiol (1082 +/- 158 ng/ml), androstenedione (15.2 +/- 3.17 ng/ml), 3 alpha-androstenediol (0.90 +/- 0.13 ng/ml), testosterone (2.23 +/- 33 ng/ml), and dihydrotestosterone (0.77 +/- 0.11 ng/ml). Follicle regulatory protein activity was 16.6% +/- 4.3% and mean inhibin level was 62.9 +/- 7.52 U. These results are in contrast to reports of follicular fluid steroid levels from normal ovulatory patients treated with exogenous gonadotropin. Although altered levels of hormones were present within these follicles, they clearly were not atretic, as evidenced by elevated estradiol levels and estradiol/androstenedione ratios. Alterations in the normal follicular response to pharmacologic gonadotropin stimulation in the follicles of anovulatory women suggest the presence of granulosa cell dysynchrony .

Adult↗