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Biomedical subjects

R S Shah

Publications and source records attributed to R S Shah.

At least 55 records · Page 3Linked to original sources
PubMed1986

Macrocytic-megaloblastic anemia in male B6C3F1 mice following chronic exposure to 1,3-butadiene.

In the present study exposure to 1,3-butadiene (BD) resulted in a macrocytic-megaloblastic anemia in male B6C3F1 mice following chronic inhalation of 1250 ppm for 6 to 24 weeks. Treatment-related changes evident after 6 weeks of exposure included a decrease in circulating erythrocytes, total hemoglobin, and hematocrit and an increase in mean corpuscular volume. A leukopenia, due primarily to a decrease in segmented neutrophils, and a five- to sixfold increase in circulating micronuclei were observed after 6 and 24 weeks of exposure. These changes were not accompanied by a significant alteration in mean corpuscular hemoglobin concentration, an increase in circulating reticulocytes, or circulating nucleated erythrocytes. A consistent treatment-related alteration in bone marrow cellularity was not found. However, flow cytofluorometric analysis of bone marrow DNA cell cycle kinetics revealed a 44% increase in proliferative index relative to controls, due primarily to an increase in the proportion of cells in S phase. These findings are consistent with a treatment-related macrocytic-megaloblastic anemia and indicate the bone marrow to be an important target organ for BD toxicity.

Anemia, Macrocytic↗
PubMed1986

Altered hematopoietic stem cell development in male B6C3F1 mice following exposure to 1,3-butadiene.

The effects of the murine lymphomagen, 1,3-butadiene (BD), on the proliferation and differentiation of hematopoietic stem cells were examined in male B6C3F1 mice. Exposure to 1250 ppm BD for 6 weeks resulted in no demonstrable alteration in the frequency of spleen colony-forming units (CFU-S); however, colonies derived from treated animals were smaller than those from controls. The absence of any difference in the frequency of CFU-GM after 6 weeks exposure suggests that BD produces an alteration in the relative proportion of immature to mature pluripotent stem cells in BD-exposed animals. This was confirmed by the examination of the effects of BD on stem cell development in long-term bone marrow culture. After 14 days, the number of CFU-GM derived from cultures of animals exposed for 6 weeks was reduced compared to controls. However, at 28 days an increase relative to controls was observed. This shift in the course of differentiation of the granulocyte/macrophage precursor cell, as assessed by the CFU-GM, provides further evidence that there is an increase in the relative frequency of primitive or immature stem cells in BD-treated mice. After a 30-31 week exposure to BD, a decrease in the numbers of both CFU-S and CFU-GM was observed. These findings indicate that BD causes alterations in stem cell development and suggest that alterations in bone marrow stem cells may play an essential role in the pathogenesis of BD-induced thymic lymphoma.

Animals↗
PubMed1986

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↗
PubMed1985

Reproductive endocrine effects of intranasal administration of norethisterone (NET) to women.

Four consecutive menstrual cycles were studied in six healthy parous women. A solvent mixture comprising propylene glycol:ethanol:water (3:3:4) was sprayed intranasally daily using a glass atomizer between days 5 and 24 of the first (control) menstrual cycle. NET was dissolved in the solvent and similarly administered at a daily dose of 100 mcg during the second and third menstrual cycles. Nasal sprays were not administered during the fourth post-treatment cycle. Blood samples were taken during four consecutive cycles between days 8 and 15 and again between days 20 and 24 of the cycle to estimate levels of estradiol (E2), FSH, LH and progesterone (P). These studies revealed that nasal sprays of NET were well accepted and that no adverse clinical effects or menstrual disturbances occurred. NET inhibited ovulation in one cycle. The E2-induced mid-cycle rise in FSH and LH was either suppressed or inhibited in nine out of the 12 treated cycles. P levels in three treated cycles were indicative of luteal inadequacy. These endocrine effects of NET persisted into the post-treatment cycle in two cases.

Administration, Intranasal↗
PubMed1984

Vitamin A status of the newborn in relation to gestational age, body weight, and maternal nutritional status.

Studies were made of the vitamin A status of newborn as judged by cord serum vitamin A in relation to gestational age, birth weight, and maternal vitamin A status in 130 + 79 mother-infant pairs belonging to low and high income groups in urban Baroda. The mean values for maternal serum vitamin A (microgram/dl, mean +/- SE) in the two groups were 21.8 +/- 0.59 (n = 130) and 29.3 +/- 0.80 (n = 79), respectively. The corresponding values for cord serum vitamin A were 13.8 +/- 0.40 and 19.6 +/- 0.64 for full-term infants and 7.5 +/- 0.44 and 12.9 +/- 0.80 for premature infants. Even for comparable levels of maternal serum vitamin A, differences were found between income groups regarding birth weight and cord serum vitamin A. Mothers of premature infants had lower levels of serum vitamin A than those of full-term infants suggesting maternal vitamin A status to be one of the correlates of prematurity. Significant correlations were found between cord serum vitamin A, maternal serum vitamin A, gestational age, and growth status. These studies suggest that a poor vitamin A status is one of the features associated with a higher prevalence of prematurity and intrauterine growth retardation found in poorly nourished populations. These findings stress the importance of satisfactory vitamin A supplies to pregnant and nursing mothers to prevent vitamin A deficiency and growth retardation in the progeny.

Birth Weight↗
PubMed1979

Family with three apparently balanced t(3;15) (p27;q22) translocation carriers. Association with deficits in language acquisition and mental retardation: a possible example of position effect in man.

A father, son, and daughter had a (3;15) (p27;q22) simple reciprocal translocation. No abnormality in the G-banding pattern was noted. The girl was most severely affected; she had an abnormal phenotype, noticeable delay in receptive and expressive language development, bilateral hearing impairment, and definite mental retardation. The boy had a moderate delay in receptive language skills, had moderate hearing impairment in one ear, and showed mild mental retardation. The father has low-set ears, some deficits in receptive language skills, is illiterate, and was found to be borderline mentally retarded. The mother and younger child do not have the translocation and are normal in terms of phenotype, intellect, and verbal skills. The accumulating evidence suggests that balanced translocations are associated with an increased frequency of intellectual deficit and congenital anomalies, and the cytogenetic mechanism may be that of position effect.

Adult↗
PubMed1977

Guanabenz and methyldopa on hypertension and cardiac performance.

In previous placebo-controlled studies, guanabenz was shown to be a safe and effective antihypertensive drug without acute effects on cardiac function. In view of its therapeutic advantages, a double-blind comparison of guanabenz with methyldopa was performed in a group of 36 patients over 6 mo. Both drugs produced statistically and clinically significant decreases in blood pressure with similar side effects. No laboratory or electrocardiographic abnormalities were found other than positive Coombs' tests which developed in 3 patients during methyldopa therapy. Cardiac performance in 26 of the patients, as measured by noninvasive techniques, showed no significant changes from either drug except for a progressive and statistically significant increase in systolic time interval (QS2) and the ratio of the pre-ejection period to left ventricular ejection time (PEP/LVET) during methyldopa therapy. For an additional 6 mo, continued efficacy and safety were shown under open conditions in those patients who had received guanabenz. The study suggests that guanabenz may be an important new antihypertensive drug because of effectiveness, absence of adverse cardiac effects, and paucity of side effects.

Adult↗
PubMed1977

Respiratory failure in pulmonary tuberculosis.

Of 852 patients admitted to Cook County Hospital with bacteriologically-proved pulmonary tuberculosis, 16 suffered respiratory failure. Of these 16, 5 died and 11 recovered. On follow-up, the survivors demonstrated significant improvement in oxygenation, but continued to show a severe restrictive ventilatory defect. Our patients, unlike those in previous reports, did not show airway obstruction. The principles of management are the same as for other pulmonary patients. Arterial blood gas analyses should be done on patients with advanced tuberculosis so that abnormalities of gas exchange will not be missed.

Adult↗
PubMed1976

Rapid prediction of need for hospitalization in acute asthma.

Sixty-seven episodes of acute asthma were treated in an emergency room. The characteristics of the attacks and subsequent course were then analyzed to determine criteria that could be used for an early decision in regard to the need for hospitalization. Attacks that were not successfully treated in the emergency room were most often characterized by very severe obstruction and a poor response to an initial injection of epinphrine. It is suggested that severely obstructed patients (peak flow less than 16% of predicted) whose peak flow remains less than 60 liters/min, or who exhibit a less than 16% improvement following 0.3 ml epinephrine, be promptly admitted.

Acute Disease↗
PubMed1976

Guanabenz effects on blood pressure and noninvasive parameters of cardiac performance in patients with hypertension.

Guanabenz (2,6 dichlorobenzylidene amino guanidine acetate) is a new antihypertensive whose mechanism of action appears to involve both central alpha adrenergic stimulation leading to suppression of sympathetic nervous system activity from bulbar vasoconstriction centers as well as peripheral adrenergic neuron blockade. In this study, the drug was shown to produce a statistically and clinically significant decrease in blood pressure during a 4-wk placebo-controlled double-blind study. For three additional months continued efficacy and safety were shown under open conditions in 17 hypertensive patients. Mild sedation occurred, but there were no postural hypotension, tachycardia, evidence of sodium retention, gastrointestinal disturbances, or electrocardiographic (ECB) abnormalities. Noninvasive parameters of cardiac performance in 10 patients after single doses of guanabenz showed no significant changes. Although the numbers of patients were relatively small, the data suggest that this new drug may be a useful antihypertensive agent that warrants further investigation.

Adult↗
PubMed1976

Bronchiectasis following heroin-induced pulmonary edema. Rapid clearing of pulmonary infiltrates.

We observed a patient who developed diffuse bronchiectasis subsequent to heroin-induced pulmonary edema. Unlike the previously reported cases, there was rapid clearing of pulmonary infiltrates and little evidence of severe aspiration. The development of bronchiectasis was attributed to a bronchial infection subsequent to clearing of the pulmonary edema. Physiologic dysfunction was characterized by marked obstruction, pulmonary hypertension, and mild hypoxemia.

Adult↗