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Biomedical subjects

M Chandra

Publications and source records attributed to M Chandra.

At least 127 records · Page 7Linked to original sources
PubMed1991

Incidence and pathology of spontaneous renal pelvis transitional cell carcinomas in rats.

Spontaneous transitional cell carcinoma (TCC) originating from renal pelvis is very rare. Metastasis from this tumor having been reported only once previously. Data from control groups of 17 carcinogenicity studies in Sprague-Dawley and 10 carcinogenicity studies in Fischer 344 (F-344) rats were reviewed and evaluated to determine the incidence and pathology of TCC. Renal pelvis TCC were observed in 1 male and 1 female Sprague-Dawley rat and in 1 male F-344 rat. Metastasis from TCC to the lung was observed in 1 male Sprague-Dawley rat. Detailed histopathological features of this tumor are described and discussed.

Animals↗
PubMed1991

Clear-cell carcinoma in the trachea of a rat.

Necropsy examination of a control Sprague-Dawley male rat from a carcinogenicity study disclosed the presence of a neoplastic mass in the trachea. Microscopic examination disclosed that the tumor consisted of closely packed cells arranged in lobules and cords separated by thin connective tissue stroma. The cells had distinct cell borders and abundant pale cytoplasm. Electron microscopic examination further disclosed that the cytoplasm contained numerous argyrophilic neurosecretory granules measuring 298 nm in diameter. These granules were positive for Grimelius silver stain. The histopathologic and electron microscopic features of this tumor are consistent with a diagnosis of clear-cell carcinoma.

Adenocarcinoma↗
PubMed1991

Development of laparoscopic anterior seromyotomy and right posterior truncal vagotomy for ulcer prophylaxis.

This study investigated the feasibility of a laparoscopic antiulcer procedure. The following antiulcer operations were performed laparoscopically in 20 pigs: truncal vagotomy and pyloroplasty (n = 5), highly selective vagotomy (n = 5), right truncal vagotomy and left highly selective vagotomy (n = 5), and anterior seromyotomy and posterior truncal vagotomy (n = 5). Each procedure was videotaped and assessed in terms of ease of access, need for additional trocars, requirements for suturing, and complexity of the procedure. The anterior seromyotomy and posterior truncal vagotomy provided the optimal combination of antiulcer prophylaxis and adaptivity to the laparoscopic approach. We employed a Nd:YAG laser operating at 20 W delivered via a 600 micron sculpted tip which simplified the anterior seromyotomy. Anterior seromyotomy-posterior truncal vagotomy was then performed in three cadavers without evidence of perforation of the stomach. Our initial experience in a 46-year-old male demonstrates that the procedure can be performed with relative ease in humans. Thus, an effective antiulcer operation, anterior seromyotomy-posterior truncal vagotomy can be performed laparoscopically and may be a reasonable alternative for treating those patients who had a poor response to medical therapy.

Animals↗
PubMed1991

Diagnosis and imaging of the fetal and neonatal abdominal mass: an integrated approach.

Almost all of the renal causes of NAM and adrenal neuroblastoma, the most common nonrenal cause, can be categorized as cystic or solid by sonography. Evaluation with CT is usually the most appropriate next step for assessment of solid renal tumors lacking clinical features of RVT. Renal scintigraphy and diuretic renal scintigraphy offer valuable information about relative individual kidney GFR and excretory function, whether normal, partially, or completely obstructed. Many dilated urinary tracts, especially those diagnosed in utero, are found to resolve spontaneously when serial studies are performed. The informed pediatrician should play a major role in the selection of diagnostic procedures and determination of management strategy. Only he or she has the detailed clinical knowledge of the patient that can give appropriate direction to the consultants. A tentative algorithm for imaging studies in the evaluation of NAM is presented in Figure 1 and emphasizes the functionally more informative radionuclide studies 15,25,26 over the traditional radiocontrast studies.

Abdominal Neoplasms↗
PubMed1991

Fine structure of Calymmatobacterium granulomatis with particular reference to the surface structure.

Ultrastructural study of C. granulomatis, the causative organism of donovanosis (granuloma inguinale), in human tissue revealed the presence of a complex cell envelope. The cytoplasm of these organisms showed presence of electron dense polar material, in addition to regular bacterial structures like mesosome, ribosomes, and nuclear material. Surface appendages i.e., fimbriae and blebs were studied in detail. Origin of these structures was clearly endogenous to the cell wall. Morphology of fimbrium at the site of its attachment to the cell membrane has been described. A distinct layer of homogenous material of varying density surrounding the organism indicated the possibility of it being a capsule.

Cell Membrane↗
PubMed1990

In vivo and in vitro effects of aldrin on rat brain synaptosomal Mg2+ and Na+,K(+)-adenosine triphosphatase.

Aldrin, a chlorinated hydrocarbon, inhibited rat brain synaptosomal membrane-bound Na+,K(+)-adenosine triphosphatase (ATPase) and Mg2(+)-ATPase activities under in vivo and in vitro conditions. Na+,K(+)-ATPase was non-competitively inhibited whereas Mg2(+)-ATPase was inhibited uncompetitively. Arrhenius plots of both these ATPases without aldrin under in vivo and in vitro conditions were found to be linear. In the presence of aldrin, on the other hand, Arrhenius plots of the same ATPases were nonlinear. Slopes of Arrhenius plots of both ATPases under in vivo and in vitro condition were changed with change in temperature with aldrin. The activation energy (AE) of Na+,K(+)-ATPase and Mg2(+)-ATPase activities were changed over the temperature range 15-40 degrees in the presence of aldrin. These results thus suggest that aldrin increases the lipid fluidity of the synaptosomal membrane which may be a cause of inhibition of neuronal membrane-bound Na+,K+ and Mg2(+)-ATPase activities.

Aldrin↗
PubMed1990

B cell lymphoma of the thyroid in Hashimoto's thyroiditis monitored by fine-needle aspiration cytology.

An 80-yr-old female with a grade I diffuse goiter was diagnosed on fine-needle aspiration cytology as having Hashimoto's thyroiditis. Two years later, she developed a hard nodular growth in the right lobe of the thyroid, which was subjected to fine-needle aspiration and diagnosed as a non-Hodgkin's lymphoma. Immunocytology demonstrated the monoclonal B cell nature of the lesion. The patient underwent total thyroidectomy and is alive and free of the disease 27 mo after surgery.

Aged↗
PubMed1990

Idiopathic arterial calcification of infancy: a case with prolonged survival.

We describe a patient with idiopathic arterial calcification of infancy and the following unusual features of the disease: (1) prolonged survival until age 11 years, (2) discordance between the extent of vascular calcification and clinical manifestations of arterial luminal occlusion, (3) a large area of myocardial calcification, (4) symptoms of cerebral-vascular insufficiency, and (5) spontaneous resolution of hypertension.

Calcinosis↗
PubMed1990

Kinetics of serotonin in platelets in essential hypertension.

In a study of the kinetics of 5-hydroxytryptamine (5-HT) in platelets in 26 hypertensive subjects with a mean systolic and diastolic blood pressure of 153.9 +/- 26.9 and 106.9 +/- 9.1 mm Hg respectively, it has been observed that in hypertensive platelets there was a marked decrease in 5-HT uptake and content, an increase in 5-HT efflux and an accompanying increase in Plasma 5-HT and 5-HIAA levels. Regression analysis of the data indicated a significant correlation between rise in diastolic blood pressure and these changes in 5-HT kinetics.

Blood Platelets↗
PubMed1990

Spontaneous primary astrocytoma in the spinal cord of a mouse and a rat.

A spontaneous astrocytoma was observed as an incidental finding in the thoracic spinal cord of a control Charles Rivers CD-1 female mouse from a 2 yr oncogenicity study. An astrocytoma was also observed in the lumbar spinal cord of a Charles Rivers Sprague-Dawley control, female rat from a 2 yr oncogenicity study. The mouse was clinically normal and was sacrificed at the end of the 2 yr study. The rat was killed at 512 days of age because of posterior paralysis.

Animals↗
PubMed1990

Low serum immunoglobulin G--a predictor of frequent relapses in idiopathic nephrotic syndrome.

Serum immunoglobulins were measured in 25 children at the onset of nephrotic syndrome, in 20 during remission and in 19 during relapse. On follow up, 10 of them were frequent relapsers (FR). As compared to children who were infrequent relapsers (IFR), frequent relapsers had significantly lower levels of IgG at onset (p less than 0.001) which persisted during remission. IgG in FR at onset and at remission were 27.2 and 42.5% of normal mean as compared to 70.0 and 74.4% of normal mean observed at onset and remission, respectively in IFR. Very low levels of IgG may help predict onset of a tendency towards frequent relapses in children with minimal change nephrotic syndrome.

Child↗
PubMed1990

Effects of commonly used NSAID's on gastric mucosa. A clinico-endoscopic and histopathological study.

Non steroidal anti-inflammatory drugs (NSAID's) are one of the most commonly used agents in clinical practice today. All these drugs are known to produce gastro-intestinal lesions. In the present study we found that aspirin, indomethacin and phenylbutazone caused gastric mucosal damage in 90.9%, 100%, respectively while ibuprofen and paracetamol caused gastric mucosal damage in 33.3% and 37.5% respectively. Thus latter two drugs were safer NSAID's. Further more we have demonstrated that endoscopic monitoring of the patients on NSAID's is a sensitive method of early detection of gastric mucosal damage. This monitoring may be particularly valuable in high risk subjects on NSAID's.

Acetaminophen↗
PubMed1990

Clinical, histopathologic & immunologic features of cutaneous lesions in acute meningococcaemia.

Fifty children with culture proven acute meningococcaemia were studied during the winter outbreak of the disease in 1986-87. Purpuric lesions were seen in 60 per cent, erythematous papules in 32 per cent, faint pink macules in 28 per cent, conjunctival petechiae in 10 per cent and herpes labialis in 20 per cent. Histopathology of skin lesions showed that the primary damage was to the dermal vessels, the extent of damage depending on the type of skin involvement. Diplococci in Gram's stained sections were seen frequently in purpuric as compared to the other skin lesions. They were located in degenerating neutrophils, endothelial cells, fibrin clots or freely in the vascular lumen. Electron microscopic study showed vascular changes accompanied by a perivascular phagocytic response. Both light and electronmicroscopy indicated the involvement of the coagulative mechanism in the pathogenesis of meningococcaemia. However, clinical parameters of clotting were often within normal limits. In the case of a child (who died eventually), a low platelet count and prolonged coagulation indices were observed. Sera from some of the children were tested for the presence of antibodies against meningococci by indirect immunofluorescence. Antibodies were detected in the sera and they may have a role in regulating the severity and course of the illness. The significance of immunoglobulin deposits in the skin lesions is not clear.

Antibodies, Bacterial↗
PubMed1990

Effects of commonly used non steroidal anti-inflammatory drugs on gastric mucosa. A clinical, endoscopic and histopathological study.

Non steroidal anti-inflammatory drugs (NSAIDS) are known to produce gastro-intestinal lesions. In the present work we found that aspirin, indomethacin and oxyphenbutazone caused gastric mucosal damage in 90.9%, 100% and 100% respectively, while ibuprofen and paracetamol caused damage in 33.3% and 37.5% of cases respectively. Thus the latter two drugs were much safer NSAIDs. Furthermore we demonstrated that endoscopic monitoring of patients on NSAIDs is a sensitive method for early detection of gastric mucosal damage. This monitoring may be particularly valuable in high risk subjects on NSAIDs.

Adolescent↗
PubMed1990

Platelet ionic calcium and serum total calcium in essential hypertension.

A total of 44 cases comprising hypertensive (31) and normotensive group (13) were studied. Serum total calcium concentrations remained unaltered in hypertensives. Platelet cytosolic calcium in hypertensive group was significantly higher as compared to the normotensive controls. Platelet cytosolic calcium correlated with systolic and diastolic blood pressure and mean arterial pressure significantly.

Blood Platelets↗