Biomedical subjects
Publications and source records attributed to R K Gupta.
A patient with the rare presentation of posterior mediastinal echinococcosis is reported. Magnetic resonance imaging (MR) demonstrated the extension of a primary retroperitoneal cyst into the posterior mediastinum which was subsequently confirmed surgically to be of echinococcal origin. Such a case of phrenomediastinal echinococcosis has been described only once before in literature.
A simple and inexpensive micromethod based on methaemoglobin reduction technique (MRT) for screening of glucose-6 phosphate dehydrogenase deficiency has been studied using reagent-impregnated curvettes incubated in a makeshift waterbath. The cuvettes shelf life has been tested upto nine months. As the test can be done with finger prick blood, it promises to be more acceptable in the field. The sensitivity of this is similar to classical MRT.
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Studies by prior workers have shown that insect repellents can act as attractants when present as low concentrations, deposits or residues. In the present study deet and ethyl hexanediol were tested in 2-fold serial doses from 1.9 X 10(-9) to 1.6 X 10(-2) mg/cm2 on the forearms of volunteers against colonized Anopheles albimanus, Aedes aegypti and Ae. taeniorhynchus. Both compounds were significantly repellent at the high end of the dose range, as expected. Neither was significantly attractant to An. albimanus in low doses. However, deet was significantly attractant to Ae. aegypti in the dose range 7.6 X 10(-9) to 1.2 X 10(-4) mg/cm2 and to Ae. taeniorhynchus in the dose ranges 1.9 X 10(-9) to 3.1 X 10(-8) mg/cm2 and 2.0 X 10(-6) to 2.5 X 10(-4) mg/cm2. Ethyl hexanediol was significantly attractant to Ae. taeniorhynchus in the dose range 1.9 X 10(-9) to 6.2 X 10(-5) mg/cm2. Based on these results and prior work of V.G. Dethier and C.N.E. Ruscoe, a model sequence of the effects of chemicals on insects with increasing dose was developed. It was concluded that the labels of commercial repellents should be amended to include instructions to wash off or reapply the repellent when it is no longer effective.
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The indirect haemagglutination (IHA) test was standardized for the assay of antibodies against Japanese encephalitis (JE) virus. Glutaraldehyde fixed sheep erythrocytes were sensitized with purified and concentrated JE vaccine (200-300% brain concentration). The JE vaccine made from Nakayama-NIH strain of JE virus was purified by protamine sulphate treatment and by ultracentrifugation in a sucrose gradient. The sensitized cells were quite stable in liquid as well as in lyophilized state both at -70 degrees C and 4-8 degrees C. These cells could be used for two years without much loss (4-8 times loss) in titre. The IHA test was as sensitive as the neutralization (N) test performed by plaque reduction method in chick embryo fibroblasts. The sensitivity of the test was influenced by the source of erythrocytes i.e., from the different sheep from which these were drawn. After standardization of the test, 16 human sera and 18 sera of immunized mice were assayed for antibodies against JE virus by N and IHA tests. There were no significant differences between titres of both human and mice sera determined by N and IHA tests (P greater than 0.05). The correlation coefficient between N and IHA titres for human sera was 0.60 (P less than 0.05) and for mice sera 0.82 (P less than 0.01). The IHA test has been found to be very simple, inexpensive, sensitive and reproducible.
Calcium is important in the maintenance of arterial smooth muscle function and its alteration from normal may predispose to atherogenesis and hypertension. Slow channel inhibitors such as nifedipine and calcium salts have been used separately to modulate arterial calcium in patients with hypertension. This study included 41 patients with essential hypertension, of whom 29 responded to calcium gluconate therapy (9.8/6.3 mmHg) and the remaining 12 (group B) showed either no response or a rise in blood pressure. Combined administration of calcium and nifedipine in responders (29 cases, group A) in a single-blind, placebo-controlled manner showed a further substantial decrease (9.6/3.2 mmHg) in pressure compared with pressures during placebo administration in both short- as well as long-term administration in group B patients. Although it is difficult to predict the positive role of calcium in hypertension, non-obese females with increased salt intake show a greater response to calcium therapy. It is possible that calcium salts plus calcium blocker therapy can further reduce the blood pressure in a particular subset of hypertensives. However, this needs further confirmation in a larger study.
Immunologic status of 43 children, 13 with bronchiolitis and 30 with bronchial asthma was studied, and compared with 10 infants and 16 healthy children of respective control groups. Humoral immunity was assessed by absolute eosinophil count and B cell count (EAC rosette method) and cellular immunity by T cell count (E rosette method) and DNCB skin test. B cell subset of lymphocytes were raised in both the study groups but associated significant eosinophilia was seen only in bronchial asthma. The study demonstrated significantly lower mean T cell count and depressed DNCB reactivity in children of bronchial asthma. Children with bronchiolitis too had significantly lower mean T cell count. Thus both humoral and cellular immunity were altered in children with bronchial asthma and bronchiolitis.
A female patient with right sided nodular goitre who presented with thyrotoxic symptoms is described. She was diagnosed as a case of hemiagenesis of the left lobe of the thyroid gland with chronic lymphocytic thyroiditis and treated with propranolol; she became euthyroid over eight weeks.
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Red-cell enzymes and reduced glutathione (GSH) were assayed on cord blood in 307 Indian neonates. On follow-up, 20 of them developed pathologic jaundice. Of these, six had red-cell enzyme/GSH deficiency, seven had associated non-enzymatic causes of jaundice, and in the remaining seven the cause could not be diagnosed. In 41 other neonates, there was enzyme/GSH deficiency without pathologic jaundice. The degree of enzyme deficiency had no relation with jaundice. Red-cell enzyme/GSH deficiency state in neonates was associated with pathologic jaundice more frequently (six of 47; 12.8%) than in the absence of such deficiency (14 of 260; 5.4%). None of the jaundiced patients had very high levels of bilirubin nor needed exchange blood transfusion. There was no reduction in haemoglobin level in the enzyme/GSH deficient group with jaundice in comparison with non-deficient jaundiced neonates or normal subjects. The incidence of red-cell enzyme/GSH deficiency appears to be high in Indian neonates; however, the majority of them do not precipitate pathologic jaundice.
The intracellular free calcium ion concentration ([Ca2+]i) of the neuroblastoma x glioma hybrid cell line, NG108-15, was measured using the 19F-nuclear magnetic resonance divalent cation indicator, 1,2-bis(2-amino-5-fluorophenoxy)ethane-N,N,N',N'-tetra-acetic acid (5F-BAPTA). The basal [Ca2+]i was measured to be 106 +/- 14 nM. Treatment with 5 microM lead (Pb) for 2 h produced a 2-fold increase in [Ca2+]i to 200 +/- 24 nM and a measurable intracellular free Pb2+ concentration ([Pb2+]i) of 30 +/- 10 pM. Intracellular free Zn2+ concentrations ([Zn2+]i) were also observed in the presence of Pb. This represents the first direct demonstration that Pb elevates the [Ca2+]i in neurons, thus providing evidence for a role of [Ca2+]i in mediating the neurotoxicity of Pb.
The quantitation of intracellular sodium ion concentration [Na+]in perfused organs using NMR spectroscopy requires a knowledge of the extent of visibility of the 23Na resonance and of the intracellular volume of the organ. We have used a multinuclear NMR approach, in combination with the extracellular shift reagent dysprosium (III) tripolyphosphate, to determine the NMR visibility of intra- and extracellular 23Na and 35Cl ions, intracellular volume, and [Na+]in in the isolated Langendorff perfused rat heart. Based on a comparison of the extracellular volumes calculated using 2H and 23Na, 35Cl, or 59Co NMR of the perfused heart we conclude that resonances of extracellular sodium and chloride ions (including ions in interstitial spaces) are fully visible, contrary to assumptions in the literature. Furthermore, prolonged hypoxia or ischemia caused a dramatic increase in intracellular Na+ and [Na+] in rose to approach that in the external medium indicating full visibility of the intracellular 23Na resonance. Resonance intensities of intra- and extracellular 23Na ions, along with a knowledge of the extracellular space as a fraction of the total organ water space, yielded an average [Na+] in of about 10 mM (10 +/- 1.5 mM) for the rat heart at 37 degrees C. Double-quantum filtered 23Na NMR of the perfused rat heart in the absence and presence of paramagnetic reagents revealed, contrary to assumptions in the literature, that both intra- and extracellular sodium ions contribute to the detected signal.
During the maturation process reticulocytes lose their intracellular organelles and undergo changes in membrane lipid composition and ion transport properties. While several reports indicate differences in the levels of magnesium, sodium and calcium in reticulocytes and erythrocytes, controversy remains concerning the actual magnitude and direction of ionic alterations during reticulocyte maturation. One problem with all of these studies is that the techniques used are invasive and are limited to measuring only the total cell ion content. We have used 31P, 23Na and 19F nuclear magnetic resonance (NMR) spectroscopy to compare the intracellular free ion and phosphometabolite levels in guinea pig reticulocytes and mature red blood cells. In contrast to a sharply decreased concentration of ATP in erythrocytes in comparison to reticulocytes, the intracellular free magnesium, measured using 31P-NMR, was increased by about 65% upon maturation (150 mumol/l cell water in reticulocytes in comparison to 250 mumol/l cell water in erythrocytes). Sizeable but opposite changes in intracellular sodium (5.5 mumol/ml cells in reticulocytes vs. 8.5 mumol/ml cells in erythrocytes) and intracellular free calcium (99 nM vs. 31 nM in reticulocytes and mature red cells, respectively) were also observed, suggesting that alterations in the kinetics of membrane ion transport systems, accompanying changes in phospholipid and cholesterol content, occur during the process of red cell maturation. However, in contrast to dog red blood cells, there was no evidence for the presence of a Na+/Ca2+ exchanger in guinea pig reticulocytes or erythrocytes.
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Cyanine and merocyanine dyes are introduced as new fluorescent reagents for covalently labeling proteins and other biomolecules. These dyes, which contain iodoacetamide functional groups, have high extinction coefficients and moderate quantum yields. A major advantage of these polymethine dyes is the easy manipulation of their spectral properties during synthesis. Cyanines containing reactive functional groups can be made with absorption maxima ranging from less than 500 nm to greater than 750 nm. This property opens additional regions of the spectrum for experiments involving the simultaneous multicolor analysis of different fluorescent probes. The cyanines, which are relatively insensitive to solvent property changes, are complemented by the merocyanines, which are keen indicators of solvent polarity.
Two cases of mucinous cystadenocarcinoma of the pancreas are described in which the diagnosis was made from the material obtained by a computed tomography-guided fine-needle aspiration cytology examination. It is strongly felt that aspiration cytology, when performed under imaging guidance, is sensitive and specific in the diagnosis of mucinous cystadenocarcinoma and allows for a relatively simple yet confident diagnostic interpretation of this uncommon pancreatic tumour.