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Biomedical subjects

R Prakash

Publications and source records attributed to R Prakash.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of a DMSA kit for instant preparation of 99mTc(V)-DMSA for tumour and metastasis scintigraphy.

A kit has been developed to instantly prepare 99mTc(V)-DMSA. The freeze-dried kit consisting of DMSA, stannous chloride and ascorbic acid in appropriate proportions, produces quality 99mTc(V)-DMSA when mixed with 0.2 mL of 3.5% NaHCO3 solution and 2-4 mL of (99mTc)pertechnetate. The radiopharmaceutical characterized by chromatography with ITLC-SG in 0.9% saline and horizontal paper electrophoresis in 50 mM vernol buffer, pH 8.6, at a potential gradient of 15 V/cm showed a different mobility with respect to 99mTc(III)-DMSA, a known agent for kidney imaging. The new agent exhibited less plasma protein binding compared to that of 99mTc(III)-DMSA. Biodistribution of the pentavalent DMSA in mouse demonstrated greater uptake in bone and muscle and lower uptake in liver and kidney with respect to trivalent DMSA. The soft tissue tumour specificity and its suitability for tumour scintigraphy was apparent from the scintigrams of mammary carcinoma in a C3H Jax mouse and medullary carcinoma in a patient. Brain metastatic lesions were also visible in a breast carcinoma patient after administering him with the agent.

Animals↗
PubMed1992

Physical and sexual growth pattern of affluent Indian children from 5 to 18 years of age.

The present study was conducted to study growth parameters on 12,899 boys and 9,951 girls of affluent class from 8 States of the country. In pooled data, the 50th centile height approached 30-40th centile till 6 1/2 years in boys and up to 10 years in girls, and ultimately the height growth curves for both fell between the 10-20th centile of NCHS standards. Similarly, for weight, they approached 10-20th centile of NCHS at the age of 17 yr. Comparison with other European countries showed that Indian affluents are shorter and lighter; however, they are similar to their counterparts of Asian origin. The secular trend for height in Delhi showed increase of 2.1 cm for boys, and 2.7 cm for girls per decade at 17 yr and 14 yr, respectively. In Varanasi, the corresponding trend was 1.5 and 2.1 cm at 16 yr for boys and girls, respectively. The mean ages for genital development stages G 2-5 were 11.9, 13.3, 14.6 and 15.9 yr; respectively. In girls, the breast development Stages B 2-5 had mean ages of 10.9, 12.8, 13.9 and 14.8 yr, respectively. The mean age for menarche was 12.6 yr. In 14 yr old boys, the mean height may vary between 150.3, 155.8, 161.2 and 165.2 cm and mean weight between 38.0, 42.5, 46.8 and 52.9 kg for genital stages G 2-5, respectively. Similarly, girls of 12.5 yr (close to menarcheal age of 12.6 yr) had mean height 145.3, 150.3, 152.1 and 153.8 cm and mean weight 34.7, 41.2, 45.4 and 54.4 kg for breast stages B 2-5, respectively. It is recommended that for growth assessment during adolescence these charts in relation to sexual development and age be used for comparison.

Adolescent↗
PubMed1992

Tc-99m(V) DMSA imaging. A new approach to studying metastases from breast carcinoma.

Combined Tc-99m MDP skeletal imaging and Tc-99m(V) DMSA whole body scans to detect metastases were performed during the follow-up of 30 patients who underwent surgery for breast carcinoma. Eight patients had normal Tc-99m MDP and Tc-99m(V) DMSA scans and were declared free of metastatic disease, further confirmed by no change in symptomatology over a 1-year follow-up period. Twenty-two patients had positive Tc-99m MDP scans with varied skeletal involvement. Tc-99m(V) DMSA scans showed matched areas of increased radiotracer concentration in bony metastases in 20 of these patients. Tc-99m(V) DMSA concentration was not seen in traumatic vertebral collapse or in coexistent osteoarthritic disease in vertebral metastatic involvement. Interestingly, Tc-99m(V) DMSA showed increased concentration in brain and liver metastases. Pentavalent Tc-99m(V) DMSA appears useful for detecting skeletal and soft-tissue metastases in breast carcinoma, and can improve the specificity of Tc-99m MDP bone scans in screening for bone metastases.

Adult↗
PubMed1991

Human platelet calcium measurements. Methodological considerations and comparisons with calcium mobilization in vascular smooth muscle cells.

Platelets are used as models for vascular smooth muscle cells (VSMC) in evaluating intracellular calcium ([Ca2+]i) metabolism in humans. This study was designed to determine if agonist-induced increases in [Ca2+]i in platelets occur via release from intracellular stores as previously demonstrated for VSMC. Incubation of purified platelets loaded with fura-2-AM in media containing 1.5 mmol/L Ca2+ resulted in higher basal [Ca2+]i than platelets incubated in Ca(2+)-free media. In addition, vasopressin-induced platelet [Ca2+]i transients were almost completely blocked by Ca2+ channel blockers. Thus, in contrast to VSMC, the transmembranous flux of extracellular Ca2+ is the major mechanism in vasopressin-induced increases in platelet [Ca2+]i, while mobilization of intracellular Ca2+ stores is only minimally involved.

Arginine Vasopressin↗
PubMed1991

Follicular thyroid carcinoma masquerading as subacute thyroiditis. Diagnosis using ultrasonography and radionuclide thyroid angiography.

The rare presentation of a follicular thyroid carcinoma mimicking the clinical and radionuclide features of subacute thyroiditis is described. Granulomatous thyroiditis was initially suspected on the clinical basis of acute onset of a hard, tender right lobe thyroid enlargement with associated systemic symptoms, modest elevation of thyroid hormone levels and suppressed thyroid RAIU. Fine needle aspiration cytology specimens were unsatisfactory for characterization. Three weeks later the thyroid RAIU was normal. The thyroid enlargement persisted, now being clearly visualized as a hypofunctional nodule on scintiscan. Repeat fine needle aspiration cytology was suggestive of acinar proliferation with hyperfunction. Ultrasonography revealed a solid nodule with a peripheral sonolucent halo. Radionuclide angiography showed intense arterial flow of Tc-99m pertechnetate through the right lobe thyroid enlargement suggestive of malignant thyroid pathology. Surgical excision and histopathological examination revealed a follicular carcinoma involving the right lobe. The possibility of carcinomatous involvement should be considered in those patients where initially tender thyroid nodularity persists longer than expected for a benign inflammatory disease, careful follow-up and relevant investigations being necessary to confirm the diagnosis.

Adenocarcinoma↗
PubMed1991

Architecture of the lower end of the human tibia.

The cancellous bone in the lower end of the human tibia is divisible into 3 broad categories, according to the density and disposition of its lamellae. Parallel fenestrated tubes of cancellous bone arise perpendicular to the inferior articular facet of the tibia and meet the shaft obliquely. They diverge from the neutral axis which inclines posterolaterally from the centre of the inferior articular facet. Horizontal lamellae course the medial malleolus, at right angle to its articular facet. The density of the cancellous bone decreases from the periphery to the neutral axis. Spicules of thin bone can be traced from the attachment of ligaments into cancellous bone lying perpendicular to the articular facets.

Humans↗
PubMed1990

Differentiation between suppressed thyroid tissue and thyroid hemiagenesis with Tc-99m pertechnetate radionuclide angiography.

Tc-99m pertechnetate thyroid angiography was performed on 62 patients who had unilateral thyroid enlargement and no radionuclide uptake in the contralateral lobe in an attempt to differentiate suppressed thyroid tissue from thyroidal hemiagenesis. In 55 cases of toxic, autonomous functioning thyroid nodules, the suppressed contralateral lobe was unequivocally demonstrated, the flow study showing tracer coursing through this tissue in the sequential arterial images. No arterial flow was demonstrable on the rapid sequence imaging in the agenetic lobe in seven patients who had thyroidal hemiagenesis. Radionuclide thyroid angiography appears a safe, simple, and accurate one-step study for distinguishing between suppressed thyroid tissue and thyroid hemiagenesis and precludes the requirement for additional studies, such as the thyrotropin stimulation test and Tl-201 scintigraphy.

Adult↗
PubMed1990

Study of innervation of the pancreatic duct of Lepus europaeus, using the cholinesterase technique.

The innervation of the pancreatic duct was studied in the European Hare (Lepus europaeus) by the cholinesterase technique. The duct was accompanied by thick myelinated and thin non-myelinated nerve fibres, which subsequently formed a plexi. The plexi were associated with the fibres of the plexi of the islet of Langerhans, or with ganglia, blood vessels or neural networks. No chain of ganglia was observed on or near the duct and the ductules.

Acetylcholinesterase↗
PubMed1989

Primary mediastinal tuberculous abscess: demonstration with MR.

An unusual case of primary mediastinal tuberculous abscess is presented in whom the diagnosis was obtained on magnetic resonance (MR) and ultrasound (US) guided aspiration cytology. Mycobacterium tuberculosis was isolated from direct smear as well as from culture of the "pus". Normal spine signal with MR and normal bone scintigraphy excluded any vertebral focus of infection. MR was helpful in, defining the extent and characterising the abscess, besides excluding a vertebral focus of infection.

Abscess↗
PubMed1989

Torsional moment to failure for carbon fibre polysulphone expandable rivets as compared with stainless steel screws for carbon fibre-reinforced epoxy fracture plate fixation.

A method of securing carbon fibre-reinforced epoxy bone plates with carbon fibre polysulphone expanding rivets was investigated. Six carbon fibre-reinforced epoxy bone plates were secured to rods with carbon fibre polysulphone rivets and six were secured with standard cortical stainless steel screws. These constructions were then subjected to pure torsional load to failure. The carbon fibre expandable rivets failed at a greater torsional moment.

Biocompatible Materials↗
PubMed1989

Technetium-99m radiocolloid scintigraphy, planar and SPECT red blood cell imaging and ultrasonography in diagnosis of hepatic hemangioma.

Technetium-99m planar sulfur colloid scintigraphy, red blood cell imaging and ultrasonography were performed in eighteen patients of hepatic hemangioma to evaluate their diagnostic utility. Radiocolloid scans detected fourteen hemangiomas in 12 patients as focal hepatic defects but missed 9 lesions smaller than 2.5 cm in the other 6 patients, accounting for a 61% sensitivity. All 23 lesions were avascular or normovascular on radionuclide flow study. Serial planar red blood cell scintigraphy showed characteristic gradually increasing focal isotopic accumulation in the 14 hemangiomas which had identifiable cold areas on the radiocolloid study. One of 6 patients with normal radiocolloid scan also showed the typical increasing blood pool pattern of hemangioma, five had normal planar scans till 1 1/2 hours. SPECT red blood cell imaging in these 5 patients detected an additional seven hemangiomas. All 7 lesions were smaller than 2.5 cm. One 1.5 cm hemangioma was missed on both planar and SPECT red blood cell imaging. Region of interest ratios in SPECT transaxial images confirmed gradually increasing concentration of labeled red blood cells in the lesions. Ultrasonography detected 22 of the 23 hemangiomas. Ten were hyperechoic, average size 2.25 cm. Twelve were of mixed pattern, generally larger, average size 7.2 cm. Sonography is useful in the detection of hepatic hemangiomas as a focal mass lesion, but the variable sonographic appearance precludes a definite pathological diagnosis. Technetium-99m red blood cell imaging appears a sensitive technique in detection of hepatic hemangioma, with SPECT being especially useful in locating smaller lesions. The addition of useful in locating smaller lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Non-invasive evaluation of global ventricular functions in coronary artery disease by exercise radionuclide angiocardiography.

Rest and exercise radionuclide angiocardiographic measurement of left ventricular functions were obtained in 12 normal subjects (group I) and 42 patients with well documented coronary artery disease (group II). Additionally thirty-five patients had an exercise tread mill test. Resting left ventricular ejection fraction less than 50% provided the greatest diagnostic information. Exercise was induced by supine bicycle exercise ergometer. In group II 32 patients of coronary artery disease with normal global ventricular function at rest, new regions of dysfunction developed during exercise and global ejection fraction fell by 8 to 15 percent while in group I there was an increase in LVEF and no areas of any ventricular wall motion abnormalities were detected. Exercise radionuclide angiocardiography is a useful non invasive technique which permits accurate assessment of the presence and functional severity of coronary artery disease.

Adult↗
PubMed1989

Glycogen in the muscles of rats poisoned by metal ions.

Glycogen was determined in the skeletal muscles of rat after exposure to several salts of mercury, cadmium, zinc, copper, molybdenum, lead, cobalt and manganese. Treatment with these metals depleted muscle glycogen except in the case of copper and zinc. The causes and significance of the changes involved are discussed.

Animals↗
PubMed1988

Abnormal resting regional cerebral blood flow patterns and their correlates in schizophrenia.

Regional cerebral blood flow (CBF) was measured under resting conditions in 108 right-handed schizophrenic inpatients and a matched group of normal controls with the xenon 133 inhalation technique. Forty-six patients were free of all medication for two weeks. There were no significant differences in CBF to the two hemispheres. The patients showed a comparatively reduced anteroposterior (AP) gradient for CBF. Though there were no differences in frontal flow, the patients had higher flow to several postcentral brain regions, bilaterally. Cerebral blood flow in the patients correlated inversely with age and positively with carbon dioxide level. Women had higher flow than men. Duration of the illness was the only significant predictor of the reduced AP gradient in patients. Higher left temporal and right parietal flow were found to be the best discriminators between patients and controls. Mean hemispheric flow to both hemispheres and several brain regions correlated with the total score and the item, unusual thought content, of the Brief Psychiatric Rating Scale. There were no differences in regional CBF between medicated and unmedicated patients.

Adult↗
PubMed1988

Carbon fibre reinforced epoxy implants for bridging large osteoperiosteal gaps.

An experimental study was undertaken to evaluate the suitability or otherwise of carbon fibre reinforced epoxy (CFRE) implants for bridging large osteoperiosteal gaps, devoid of periosteum. Using the basic principles of composite mechanics and simple design criteria, CFRE implants were designed and developed. These implants were put in simulated osteoperiosteal gaps in the ulna of healthy mature rabbits. Ten wk postoperative results clearly demonstrated that implants made of CFRE induced callus bone formation (in the form of woven bone) which totally encapsulated the implant thereby providing reunion of the two bone segments. Further follow-up showed formation of lamellar bones and formation in the pores of the implant. Radiological and scanning electron microscopical evidence is presented.

Animals↗
PubMed1988

Acute effect of decaffeinated coffee on heart rate, blood pressure, and exercise performance in healthy subjects.

The effect of decaffeinated coffee on the cardiovascular exercise performance in nine healthy volunteers was evaluated in a double-blind randomized fashion. The heart rate, blood pressure, and duration of exercise were unchanged, and no arrhythmias or ischemic changes were seen on the electrocardiogram after drinking decaffeinated coffee. It was concluded that decaffeinated coffee has no discernible, acute, adverse cardiovascular effects.

Adult↗