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Biomedical subjects

R Desai

Publications and source records attributed to R Desai.

At least 73 records · Page 4Linked to original sources

Prolactin secretion in Sheehan's syndrome. Responses to thyrotropin-releasing hormone and metoclopramide.

The prolactin response to thyrotropin-releasing hormone (TRH) and metoclopramide was studied in 16 patients with Sheehan's syndrome and 16 matched controls in the follicular phase. Metoclopramide resulted in a greater prolactin response than TRH did in the controls. However, both stimuli failed to evoke any appreciable prolactin response in the patients with Sheehan's syndrome. Since metoclopramide is generally free of side effects and far cheaper than TRH, we recommend the prolactin response to metoclopramide as the preferred screening test in the diagnosis of Sheehan's syndrome.

Adult↗

Insulin secretion in healthy Indian volunteers.

The insulin response to a 100 g oral glucose load was studied in 20 non-obese, healthy Indian females and 20 matched Indian males. There were no differences between the mean glucose responses of the two groups. However, early-phase (0-60 minutes) insulin release was significantly greater in the females. While there were no significant differences between the two groups when the total areas under the insulin and glucose curves were computed, the female volunteers had a significantly higher mean insulinogenic index. It therefore appears that healthy Indian females have significantly greater early-phase insulin release than their matched male counterparts.

Adult↗

Intravenous glucose tolerance tests in women with twin pregnancy.

Carbohydrate metabolism was evaluated in 20 twin gestations and 20 singleton pregnancies. The groups were matched for age, parity, weight, height, and gestational age. Intravenous glucose tolerance tests were performed on all women in the third trimester of pregnancy using a glucose load of 0.5 g/kg body weight. Venous plasma glucose and insulin level were measured and statistically compared. The glucose disappearance rates (K) were not different in the two groups. No significant differences in the mean insulin or glucose responses were found between singleton and twin pregnancies. Thus, twin gestations are not at higher metabolic risk of gestational diabetes than are singleton pregnancies.

Adult↗

Small calvarial bone scan foci--normal variations.

In a series of 3,000 bone scans reviewed retrospectively 21 (0.7%) small calvarial foci were observed. Seventeen of these lesions were found along skull suture lines. No evidence for metastatic disease could be found. Skull radiographs were normal and follow-up bone scans demonstrated no change in the size or location of the lesion. These intense calvarial foci are thought to represent normal variations; among the possibilities are subradiographic cartilaginous rests, sutural foramina, or enlarged Pacchionian granulations.

Diagnosis, Differential↗

A prospective study of intrapulmonary fat accumulation in the newborn lung following intralipid infusion.

In order to assess the safety and stability of a parenteral fat emulsion (Intralipid) in total parenteral nutrition (TPN), 29 infants were infused Vamin glucose and Dextrose electrolyte solution as well as one of two isocaloric regimens; either 25% Dextrose (Group I) or 10% Intralipid (Group II). Regular biochemical monitoring was performed in all cases and no infants became lipaemic nor developed abnormally high levels of total free fatty acid. Eight infants died and only those who had received fat emulsion had lipid staining material distending the pulmonary vessels. One infant having low infusion rates of Intralipid had massive fat accumulation in the lungs, but biochemistry during life had been normal. We speculate that in ill infants the emulsion becomes less stable and agglomeration of fat particles occurs which are then fully filtered out by the lungs before metabolism of the exogenous fat can occur.

Clinical Trials as Topic↗

Effects of chrysotile on a lysosomal enzyme preparation and on the hydrolytic enzyme activity of cultured alveolar macrophages.

The interaction between chrysotile and three lysosomal enzymes (acid phosphatase, acid RNase and acid protease) in isolated lysosomal enzyme-rich preparations (LEP), from sheep alveolar macrophages maintained in the presence and absence of serum components or pulmonary surfactant at pH 5.0 and pH 7.0 for up to 22 days, is investigated. It is concluded that chrysotile does not inhibit or enhance lysosomal enzyme activity at either pH but may preferentially absorb specific enzymes and that the binding reaction between any given enzyme and mineral can be dependent on the presence of other organic compounds. The release of three hydrolytic enzymes (beta-galactosidase, acid RNase and protease) from cultured rabbit alveolar macrophages, in the presence of different concentrations of bovine serum (5-20%) and in the presence and absence of chrysotile for 72 hr, was also studied. Chrysotile enhances early differential release of each hydrolytic enzyme, but after 72 hr both control and chrysotile-treated cultures (maintained in 10-20% serum) have very similar intra- and extracellular levels of hydrolytic activity. The apparent differential release of lysosomal enzymes by untreated macrophages, which is dependent on serum concentration and time in vitro, is discussed.

Animals↗

Low-dose streptokinase for occluded Hickman catheters.

In 14 patients, 16 episodes of occluded Hickman catheters were evaluated by contrast venography. In 13 instances, a fibrin sheath occluding the distal catheter was observed. A mechanical problem was responsible for occlusion in three catheters. Low-dose streptokinase effectively restored lumen patency in 12 catheters (92%) occluded by a fibrin sheath.

Catheterization↗

Is fetal respiratory function a major determinant of perinatal survival?

A high proportion of infants who die in the perinatal period have undersized lungs of reduced weight and DNA content relative to body weight. Failure of formation or leakage of amniotic fluid causes a spectrum of changes varying from severe failure of growth and maturation of the lung to a predominantly maturational deficiency. The changes are associated with narrow airways suggesting a failure to secrete or retain lung liquid. Conditions in which there is reduction of thoracic volume, or certain neural and muscular abnormalities, are associated with failure of lung growth without impaired maturation. Studies in animals indicate that liquid secretion into the fetal airways and breathing movements are essential for normal lung growth. Such functions are readily inhibited by operations, drugs, or non-specific forms of stress. The success or failure of adaptation to extrauterine respiration may often be determined by the balance of actors influencing respiratory function in early fetal life.

Amniotic Fluid↗

beta-hemolytic streptococcal infection appearing as persistent fetal circulation.

Sixty neonates who were transferred to a neonatal intensive care unit during a four-year period had diagnoses of persistent fetal circulation (PFC). Six of these 60 neonates had beta-hemolytic streptococcal infection. The clinical appearance of these six neonates included respiratory distress, cyanosis, and/or apnea. The chest roentgenograms showed mild to moderate lung disease. All six neonates had progressive acidosis with hypoxemia. The diagnosis of PFC was made by cardiac catheterization or contrast echoangiography. The neonates were treated with mechanical ventilation, antibodies, and supportive therapy, including tolazoline hydrochloride. Mortality was high; only one of the six neonates survived. Streptococcal infection should be added to the growing list of conditions associated with PFC.

Apnea↗

High prevalence of symptomatic bradyarrhythmias due to atrioventricular node-fascicular and sinus node-atrial disease in patients with mitral anular calcification.

Mitral anular calcification (MAC) is associated with high frequency of conduction defects. To delineate this association in patients with symptomatic bradyarrhythmias, 68 consecutive patients requiring pacemakers (group I) and 56 matched controls (group II) were studied. The patients comprised 41 men and 27 women, whose ages ranged from 24 to 92 years (mean 68). The control group consisted of 56 subjects without bradyarrhythmias, whose ages ranged from 30 to 86 years (mean 70); there were 36 men and 20 women. MAC was detected in 59 patients (87%) with symptomatic bradyarrhythmias compared with 8 subjects (14%) in the control group. In group I, 15 patients (22%) had complete atrioventricular block, 23 patients (34%) had atrial fibrillation with slow ventricular response, and 30 patients (44%) had intermittent sinus arrest. The incidence of MAC was similar among these subgroups (93%, 83%, and 87%, respectively). Thus the present study confirms the strong association of MAC with symptomatic bradyarrhythmias.

Adult↗

Chemistry and hypoglycemic activity of benzimidoylpyrazoles.

A series of benzimidoylpyrazoles was synthesized and evaluated as hypoglycemic agents. Methyl 1-(N-cyclohexylbenzimidoyl)-5-methyl-3-pyrazolecarboxylate (13) and methyl 1-[N-(4-methoxyphenyl)benzimidoyl]-5-methyl-3-pyrazolecarboxylate (33) are two of the more interesting compounds. A comparison of these benzimidoylpyrazoles with classical standards (tolazamide, phenformin, and buformin) in several experimental models show that these compounds seem to combine in one molecule some of the biological activities of the beta-cytotrophic sulfonylureas and some of the activities of the biguanides. A synthetic scheme for the preparation of the benzimidolypyrazoles and a preliminary structure-activity relationship are presented.

Adrenalectomy↗

Use of DNA estimation for growth assessment in normal and hypoplastic fetal lungs.

Total DNA was estimated in the lungs of 80 fetuses and newborn infants varying in gestation from 14 weeks to term. In fetuses of appropriate weight for gestational age total lung DNA increased at a constant rate from about 35 mg at 17 weeks' gestation to 480 mg at term. The lungs of immature fetuses were heavier and contained more DNA relative to body weight than did those of mature infants. Small-for-dates infants had lower lung DNA levels for gestation than infants with weights appropriate for gestational age, but there was no difference when lung DNA was corrected for body weight. Lung hypoplasia defined in terms of lung/body weight ratio was associated with low lung DNA content for gestation, even when corrected for body weight. The total lung DNA at 34-40 weeks' gestation in infants with lung hypoplasia associated with fetal anuria or urinary outflow obstruction was equivalent to that seen in normal fetuses at 20-22 weeks' gestation. We conclude that the early second trimester is a critical period for human fetal lung growth.

Body Weight↗

Fetal lung hypoplasia: biochemical and structural variations and their possible significance.

Quantitative biochemical criteria for lung growth and maturation were compared with the histological appearances in hypoplastic lungs from 20 fetuses and newborn infants. Cases associated with oligohydramnios showed a characteristic series of changes with narrow airways, retardation of epithelial and interstitial growth, delay in development of blood-air barriers, and low concentrations of phospholipid phosphorus, lecithin phosphorus, total palmitate, and lecithin palmitate. The growth and maturation arrest appeared to affect the peripheral part of the acinus. Examples of other types of lung hypoplasia showed different features. Hypoplastic lungs from infants with normal or increased amniotic fluid were of mature structure with phospholipid concentrations similar to those of infants with normally developed lungs at term. The hypoplastic left lung in 2 cases of congenital diaphragmatic hernia had an immature structure with low phospholipid concentrations, whereas the right lung has structurally and biochemically more mature. It is suggested that fetal lung growth may be impaired by any influence which reduces thoracic volume but that maturation arrest is due specifically to loss of the ability to retain lung liquid.

DNA↗

Pulmonary fat accumulation after intralipid infusion in the preterm infant.

Eight preterm infants who died after 'Intralipid' infusion had fat accumulation in the lungs. The rate of infusion in six of the infants was below the recommended maximum for preterm infants and in no case was the plasma lipaemic on regular visual inspection. Histological examination revealed varying degrees of lung involvement. The commonest finding was distension of empty pulmonary capillaries, but specific staining techniques for fat showed that the capillaries were engorged with large lipid globules. Removal of accumulated fat by histiocytes was seen in infants dying some time after cessation of intralipid infusion. Analysis of homogenised lung showed that those who died after intralipid infusion had a significantly greater (p < 0.001) concentration of lioleic acid, a marker for intralipid, than infants who died without receiving parenteral fat solution. Fat accumulation after intralipid infusion may be common but unrecognised and may seriously exacerbate ventilation/perfusion inequalities.

Capillaries↗

Effect on lung growth of cervical cord section in the rabbit fetus.

Experiments were performed to clarify the mechanism by which cervical cord transection retards lung growth in the fetal rabbit. In 10 sets of fetuses operated on at 24 1/2 days gestation and studied 3--4 days later, cord section at C1--C3 (high section) caused a significantly greater reduction in lung weight and lung DNA than cord section at C5--C8 (low section) as compared with control littermates. Comparison with the lungs of additional control fetuses removed at the time of operation showed that high section had reduced lung growth by 70% and low section had reduced growth by 40% relative to sham-operated controls. The hypoplastic lungs of the high-section group had poorly expanded, thick-walled terminal sacs, while those of the low section group more nearly resembled the controls. Fetal weights and weights of liver, kidneys, thymus and diaphragm did not differ significantly between the groups, but the hearts of the low-section group were unduly large. In a separate 6 sets of fetuses tracheal ligation at the time of high-cord section was found to result in large fluid-filled lungs with a normal DNA content. The results indicate that preservation of an upper motor neurone supply to the phrenic nucleus is of critical importance for fetal lung growth, and confirm the growth-promoting effects of liquid distension of the fetal lungs. We conclude that normal fetal lung growth depends on development and maintenance of a sophisticated form of function involving integration of respiratory movements and lung lipid secretion. This functional control of fetal lung growth has important implications for perinatal medicine.

Animals↗