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Biomedical subjects

U M Joshi

Publications and source records attributed to U M Joshi.

At least 37 records · Page 2Linked to original sources

Interactions between cimetidine, methylparathion, and parathion.

The purpose of this study was to determine whether cimetidine exerts a protective effect against toxicity of organophosphate pesticides requiring metabolic activation in mice and rats. In both species, pretreatment with cimetidine (75 mg/kg/ip) 30 min prior to methylparathion (MP) reduced lethality and delayed the onset of cholinergic signs of toxicity. In contrast when cimetidine was administered simultaneously with MP to mice, neither MP-induced lethality nor cholinergic signs of toxicity were altered. Moreover, cimetidine pretreatment failed to decrease parathion-induced toxicity in mice. In conclusion, pretreatment with cimetidine decreases the toxicity of MP but not of parathion in mice and rats.

Animals↗

Antacid does not reduce the bioavailability of oral contraceptive steroids in women.

The bioavailability of contraceptive steroids was studied in 12 women who were given an antacid and a contraceptive pill simultaneously. They were given a single pill containing ethinyl estradiol (EE2) 30 micrograms in combination with either norethisterone (NET) acetate 1 mg (n = 6), or levonorgestrel (LNg) 150 micrograms, (n = 6). Blood samples were collected up to 24 hours. Four weeks later the same pill was administered along with a single tablet of antacid (magnesium trisilicate 0.5 g and dried aluminum hydroxide 0.25 g) and blood samples were collected as before. Serum levels of NET, LNg and EE2 were measured by radioimmunoassay. No effect of antacid administration on bioavailability of any contraceptive steroid was observed as judged by peak levels and areas under concentration-time curve (AUC). Incidentally, significantly higher serum concentrations of EE2 were observed when it was administered in combination with NET than with LNg. The possible reasons for this finding are discussed.

Adult↗

Impact of hormonal contraceptives vis-à-vis non-hormonal factors on the vitamin status of malnourished women in India and Thailand. World Health Organization: Special Programme of Research, Development and Research Training in Human Reproduction. Task Force on Oral Contraceptives.

The effects of combined oral contraceptives containing 30 or 50 micrograms ethinyl oestradiol and 150 micrograms levonorgestrel or a 3-monthly injectable preparation depo-medroxyprogesterone acetate (DMPA) on the vitamin status of low-income group women from two urban centres in India (Bombay and Hyderabad) and one rural centre in Thailand (Chiang Mai) were examined in a follow-up study over a period of 1 year. The magnitude of malnutrition in the study population vis-à-vis a middle-income reference group was assessed by comparing the baseline data on the two groups. Effects of time-related variables such as lactation and season were also examined by a cross-sectional analysis of the baseline data on the study population. In all three centres the majority of the study population suffered from biochemical riboflavin and/or pyridoxine deficiency even before initiating contraception. Lactation appeared to have an effect on the vitamin status, which varied among the different populations. Seasonal effects were seen, but showed inconsistent trends in the three centres. Both the oral contraceptive pills and DMPA tended to increase serum vitamin A and blood folate. The thiamin, riboflavin and pyridoxine status of the women who were already deficient did not deteriorate further with the use of hormonal contraception, as judged by enzyme saturation tests. Some deterioration in the riboflavin status of the normal women of Hyderabad was seen with the use of oral pills. Women who were biochemically deficient prior to the use of oral contraceptives tended to show some improvement in B-vitamin status, over the 1-year period of hormonal contraception.

Adolescent↗

Phase I comparative clinical trial with subdermal implants--bioabsorbable levonorgestrel or norethisterone pellet fused with cholesterol.

The potential for antifertility effect of two bioabsorable pellets, one containing norethisterone (NET) and the other containing levonorgestrel (LNG) fused with cholesterol, was studied in a group of healthy, menstruating but sterilised women. The pellets weighed approximately 30 mg and contain 85% steroid and 15% cholesterol. A single NET pellet was inserted in 4 subjects, out of which 2 were also studied for steroid pattern in blood. After reaching peak levels within 48 hours, the plasma NET levels declined gradually within a fortnight's time, and thereafter, ranged between 200 to 700 mg/ml up to 90 days post-insertion. After this period, occassional spurts of NET release were seen. Bleeding pattern was studied in 37 cycles; mid-luteal progesterone (P) estimation was done in 16 cycles, mid-cycle cervical mucus was studied in 27 cycles and post-coital test (PCT) in 7 cycles. Cycle length with pellet insertion was of 25 to 37 days duration except one cycle of 55 days duration. All cycles studied during the treatment were ovulatory (P greater than 5 ng/ml) and no consistent effect was observed on cervical mucus as well as on PCT. Thus, a single NET pellet does not seem to have a reliable contraceptive potential. A single LNG pellet was inserted in 8 subjects, and steroid patterns were studied in 6 women. Peak levels of LNG were reached within 24 hours of pellet insertion and the levels fell gradually in a week's time. Thereafter, LNG levels ranged between 100-400 pg/ml up to 8 months. In contrast to the observation with NET pellets, only one subject showed frequent spurts of LNG release until the 4th month of treatment. Bleeding pattern was studied in 90 cycles, P was estimated in 52 cycles, mid-cycle cervical mucus studied in 55 cycles and PCT done in 26 cycles. Breakthrough bleeding (BTB) occurred on 15 occasions, 11 episodes being in 2 subjects. Cycle length varied between 21 to 42 days. The LNG pellet did not exert a consistent effect either on ovulation inhibition or cervical mucus or PCT. In their present form, therefore, a single LNG pellet also does not appear to have a reliable contraceptive effect.

Absorption↗

Histological observations on the liver of Tilapia mossambica after exposure to monocrotophos, an organophosphorus insecticide.

The histological changes in the liver of Tilapia mossambica were observed after exposure to a sublethal level (2.5 ppm) of monocrotophos. The changes observed after 2 days of exposure were characterized by necrosis and vacuolation of hepatocytes. Fatty degeneration was observed after 10 days of exposure. However, normalization of histological picture was evident after 15 days of treatment, though some patches of degenerating zones were also found to exist concomitantly. A wave of secondary intensively degenerative changes was observed from 30 days up to 45 days of experimentation. The possible significance of histological lesions and adaptation to exposure after sublethal doses as well as continuous exposure are discussed.

Animals↗

Penicillinase as a marker in enzyme-linked immunosorbent assays for steroid hormones.

Using penicillinase (E.C. 3.5.2.6) as marker and microtitre ELISA plates for immunoadsorption, sensitive and specific assays for two steroid hormones viz. testosterone in plasma and estrone-3-glucuronide in urine were developed. The entire assay can be performed in 4 h and requires simple laboratory equipment such as an incubator and a colorimeter. The enzyme labelled steroids have a shelf life of more than 3 years.

Cross Reactions↗

A simple, rapid and reliable enzyme-linked immunosorbent assay (ELISA) for measuring estrone-3-glucuronide in urine.

A rapid, simple and sensitive enzyme-linked immunosorbent assay for the estimation of estrone-3-glucuronide (E1G) in diluted unprocessed urine has been developed using E1G-penicillinase (E.C.3.5.2.6.) prepared via carbodiimide linkage. Polyvinyl chloride ELISA plate (Dynatech) coated with antibody was used for separation of the antibody bound ligand. A complete assay could be performed within 4 hours with good precision (C.V. less than 17%). Minimum detectable amount of E1G was 25 pg/well. Parallelism was observed between sample dilution curve and standard curve. Recovery of E1G from urine ranged between 85-105%. Results obtained on 29 urine samples by the ELISA procedure were comparable to those obtained with an established RIA procedure (r = 0.96). The present method may thus provide a useful tool for the assessment of ovarian function.

Enzyme-Linked Immunosorbent Assay↗

Clinical performance and endocrine profiles with contraceptive vaginal rings containing a combination of estradiol and D-norgestrel.

Contraceptive vaginal rings (CVRs) impregnated with a combination of estradiol and d-norgestrel were studied in 39 women. The rings were inserted as three weeks "in" and one week "out" schedule to allow withdrawal bleeding. Ovulation was inhibited in all cycles and promptly resumed on completion of the treatment cycles. Bleeding control was excellent. Incidence of breakthrough bleeding was 2.11 per cent in 273 cycles studied, with 89 per cent of the cycles within the acceptable range (25 - 35 days). Levels of estradiol after an initial rise were maintained between 50-100 pg/ml and, d-norgestrel levels were relatively constant between 1.8-3 ng/ml during the period while the ring remained in situ. Clinical acceptance was good. The main problem encountered was of spontaneous expulsion of the ring in the toilet, which might be due to the squatting toilet habits of Indian women and laxity of vaginal wall.

Alkaline Phosphatase↗

Endocrine and accessory sex organ function after vasectomy and vasovasostomy.

There are no major short- or long-term changes in pituitary testicular axis due to vasectomy. The response of the prostate and epididymis to endogenous may be altered after vasectomy. However, the secretory functions of the two organs return to normal after vasovasostomy. The effects of vasectomy and vasovasostomy on the pituitary gonadal axis and on the accessory sex organs' function are reported.

Cross-Sectional Studies↗

A simple and sensitive color test for the detection of human chorionic gonadotropin.

A simple, rapid, sensitive, and reliable ELISA test for the detection of urinary human chorionic gonadotropin (hCG) has been developed using penicillinase (EC no. 3.5.2.6) as the label and a microtiter ELISA plate as a solid support for antibody. The results of the test is assessed visually for the dark blue that indicates the presence of hCG. A minimum of 500 mU of hCG/ml of urine can be detected easily and the test can be completed in 2 hours with good precision. Accurate negative results are obtained in urine samples of normally ovulatory women, postmenopausal women, and adult males, suggesting that the physiologic concentrations of luteinizing hormone do not influence the assay results. In samples referred for pregnancy detection 95.5% accurate results were obtained when compared with histopathologic and/or clinical findings. There were 2 false-negative results, and only in 4 of 132 subjects studied were false-positive results obtained. This test, if properly performed, should prove a valuable tool in the detection of hCG as early as 30 to 35 days from the last menstrual period.

Chorionic Gonadotropin↗

A study of interaction of a low-dose combination oral contraceptive with anti-tubercular drugs.

Low-dose combination contraceptive (containing norethisterone acetate 1 mg and ethinyl estradiol 30 micrograms) was administered to women receiving concurrent therapy with either Rifampicin or "triple" antitubercular treatment consisting of paraaminosalicylic acid (PAS), isonicotinic acid hydrazide (INH) and streptomycin. Plasma levels of norethisterone (NET) and ethinyl estradiol (EE), PAS and INH were measured and the area under curve (AUC) was calculated for NET and EE. Rifampicin treatment (9 women) caused a statistically significant reduction of the plasma NET levels as well as the AUC of NET. In this group of women, though a trend for reduction in EE levels was observed in individual subjects, it was not statistically significant. Out of 7 regularly menstruating women on Rifampicin therapy, 2 showed a premenstrual rise of plasma progesterone (P) levels (> 4 ng/ml) suggesting an ovulatory cycle and 3 experienced menstrual irregularities. In contrast, plasma levels of NET and EE as well as their AUCs were not altered in 8 women receiving "triple" antitubercular therapy. Only one woman out of 8, had menstrual irregularity and all women had P levels in the anovulatory range. Furthermore, oral contraceptive treatment did not alter the plasma levels of PAS and INH.

Adult↗