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Biomedical subjects

R Christopher

Publications and source records attributed to R Christopher.

At least 19 recordsLinked to original sources
PubMed2000

Type I hyperprolinemia.

Type I hyperprolinemia is an autosomal recessive disorder characterized by increased plasma and urine proline concentrations due to a deficiency of the enzyme, proline oxidase. This rare inborn error of proline metabolism is generally believed to be a benign condition although many associated clinical abnormalities have been reported. We report two siblings with Type I hyperprolinemia who presented with recurrent seizures. They had elevated plasma proline levels with massive prolinuria without an increased urinary excretion of delta 1-pyrolline-carboxylic acid.

Female↗
PubMed2000

Expression of p67 (Munc-18) in adult human brain and neuroectodermal tumors of human central nervous system.

p67 (Munc-18), is a neuron-specific protein of 67 kDa, known for its ability to bind with syntaxin and also to copurify with neuronal cdc2-like kinase. Earlier, in situ hybridization and immunocytochemical analysis of rat trigeminal ganglion and hippocampal cells demonstrated the specific localization of p67 in nerve cells and its rich distribution in axons. In the present study, we have looked for p67 expression in normal human brain and various neuroectodermal tumors. Immunohistochemical and Western immunoblot analysis of normal human brain tissue using antibodies against the N- and C-termini of p67 demonstrated the specific localization of this protein in postmitotic neurons but not in glia. Among neuroectodermal tumors, expression of p67 was observed in 100% of the tumors of neuronal origin studied, especially in the mature neuronal cell population of these tumors. Western immunoblot analysis of non-neuronal neuroectodermal tumors failed to reveal the expression of this protein in majority of cases. However, in gliomas and meningiomas, mild cytoplasmic immunohistochemical staining of neoplastic cells was noted in 64.7% and 25% of cases, respectively. Observed mild immunohistochemical staining of these tumors could be due to immunoreactivity to low molecular weight degraded products of p67, as seen on Western blot. The findings suggest that p67, by virtue of its ability to be expressed in postmitotic neurons of adult human brain and in tumors of neuronal origin, may serve as a molecular tool to understand the growth and differentiation of the nervous system in general.

Adult↗
PubMed2000

Safety of acute normovolemic haemodilution with hydroxyethyl starch during intracranial surgery.

The effect of acute normovolemic haemodilution on haemodynamics, serum osmolality and coagulation parameters was studied in 20 patients undergoing intracranial surgical procedures. After induction of anaesthesia, 740+/-153 ml of blood was collected and the same was replaced with an equal volume of 6% hexaethyl starch. Heart rate (HR), blood pressure (BP), central venous pressure (CVP) and end tidal carbon dioxide tension (Et CO2) were monitored for 45 min. Haemoglobin concentration (Hb), haematocrit (Hct), serum osmolality (Osm), bleeding time (BT), prothrombin time (PT) and platelet count were determined before and 45 min after haemodilution. Hb and Hct were significantly lower following haemodilution (13.1+/-1.8 and 10.3+/-1.7 g/dL for Hb and 38.0+/-4.6%. and 30.1+/-4.5% for Hct). There was no significant change in the HR, BP and Et CO2 throughout the study period. CVP increased marginally from 35 to 45 min but was within normal limits. There was no significant change in serum osmolality, bleeding time and prothrombin time following haemodilution. Platelet count decreased following haemodilution but the values were within normal limits. The brain relaxation, as assessed by a semiquantitative scale, was satisfactory in all cases. None of the patients developed intraoperative brain swelling. In conclusion, acute normovolemic haemodilution with hexaethyl starch is tolerated well haemodynamically. It does not cause changes in serum osmolality which can increase brain oedema. It has no adverse effect on intraoperative haemostasis. It is a safe technique to decrease homologous blood transfusion during intracranial surgery.

Adult↗
PubMed1999

Anticardiolipin antibodies: a study in cerebral venous thrombosis.

OBJECTIVES: Anticardiolipin antibodies (aCL) have been recognized as a marker for an increased risk of thrombosis. There are no documented reports from India on the prevalence of aCL in patients with cerebral venous thrombosis (CVT). Our study aimed at establishing the prevalence of these antibodies in patients with CVT and evaluating their clinical significance. SUBJECTS AND METHODS: Thirty-one patients with CVT diagnosed by angiography and/or cranial CT were investigated for the presence of aCL along with 31 age- and sex-matched normal controls. All subjects had no overt evidence of systemic lupus erythematosis or related autoimmune disorders. The titres of IgG and IgM type of aCL were estimated in the sera using a solid phase enzyme-linked immunosorbent assay. RESULTS: Anticardiolipin antibodies were detected in 22.6% of CVT patients compared to 3.2% of normal controls (95% confidence interval (CI) 1.01 to 75.65). Five CVT patients had both IgG and IgM antibodies, and 2 had only IgG antibodies. The aCL positive group did not differ from the aCL-negative group with respect to the clinical characteristics and the demographic and risk factor profile. CONCLUSION: The findings suggest that anticardiolipin antibodies are a risk marker for cerebral venous thrombosis. Further studies on a larger group of patients are needed to establish the role of aCL in the pathogenesis of CVT.

Adult↗
PubMed1999

Non-traumatic acute rhabdomyolysis.

A boy developed sudden severe generalized muscle stiffness, bulbar weakness and passed dark coloured urine. Laboratory tests revealed marked elevation of creatinine kinase(CK) levels and myoglobinuria. Histopathology of quadriceps muscle showed features of acute rhabdomyolysis. Patient made complete clinical recovery over a period of three weeks and CK returned to normal level. The possible aetiologies of non-traumatic rhabdomyolysis are discussed and the relevant literature reviewed.

Acute Disease↗
PubMed1999

Plasma antithrombin III deficiency in ischaemic stroke in the young.

A deficiency of plasma antithrombin III has been identified as a potential risk factor for thrombosis. In a pilot study of 56 patients aged less than 40 years who presented with ischaemic stroke of unknown etiology, we detected only one case of plasma antithrombin III deficiency. Antithrombin III activity was estimated by a chromogenic assay. Hence, antithrombin III deficiency, though rare, should be considered while evaluating young patients with stroke of unknown etiology.

Adult↗
PubMed1999

An intrasubject comparison of two doses of succinylcholine in modified electroconvulsive therapy.

UNLABELLED: The electroconvulsive therapy (ECT) guideline of the Royal College of Psychiatrists recommends a 0.5 mg/kg of succinylcholine for ECT modification. Our clinical experience suggests that this dose is insufficient for Indian patients. The dose recommended by the Royal College of Psychiatrists (0.5 mg/kg) and a larger dose (1 mg/kg) were compared in 50 patients referred for ECT. In one ECT session, patients were equally randomized to receive one of the two doses and in the next session they were switched to the other dose. The extent of motor seizure modification was rated on a five-point scale by two independent raters who were blinded to the succinylcholine dose. The interrater reliability was good (K = 0.85). "Poor" seizure modification occurred in 48% and 12% of patients with the 0.5 and 1 mg/kg doses, respectively. Of the 24 patients who had poor modification with 0.5 mg/kg, 20 had "good" modification in the session with 1 mg/kg (P < 0.001). A small delay (mean = 55 s) occurred in time to recover from the respiratory paralysis with the 1 mg/kg dose of succinylcholine. No patient, however, had prolonged apnea requiring special measures. We recommend 1 mg/kg of succinylcholine dose be used in the first ECT session. For subsequent sessions, the dose may be altered, depending on the response for optimal motor seizure modification. IMPLICATIONS: The dose of muscle relaxant (succinylcholine) recommended in modified electroconvulsive therapy is not based on empirical research. In the same patients (n = 50), two doses-0.5 mg/kg and 1 mg/kg-were compared during different electroconvulsive therapy sessions. The larger dose was more effective in modifying the peripheral convulsion.

Adult↗
PubMed1999

Preceding infection as a risk factor of stroke in the young.

INTRODUCTION: The cause of stroke in the young remains unknown in 20-50% of the patients. Infections preceding stroke have been recently recognised to be an independent risk factor of stroke. MATERIAL AND METHODS: Sixty consecutive patients aged 40 years or less presenting with ischaemic completed stroke are taken up for the study. Patients with neurological deficit of less than 24 hours, evidence of haemorrhage on CT scan, infection occurring after the onset of stroke were excluded. Controls consisted of age and sex matched persons residing in the same area. Both the groups were enquired about preceding fever and infections and were examined for evidence of infections. Serum was examined for antibodies against measles, herpes simplex, and Japanese B encephalitis viruses. Cultures were put up from appropriate samples and CSF examined in patients only. RESULTS: Evidence of infection was noted in 26 (43.3%) of patients and 6 controls (p < 0.001). History of fever was elicited in 23 patients and 3 controls while 15 patients were febrile on examination at admission. Signs of local infection was observed in 14 patients and one control. The commonest site of infection was respiratory tract. Cultures were positive in 11 patients, commonest being beta haemolytic streptococci in six from throat. Conventional risk factors were identical in both groups of patients with and without evidence of preceding infection. Smoking and alcoholism were significantly higher in patients with preceding infection. CONCLUSION: Preceding infection is an important risk factor of stroke in the young. Smoking and alcoholism are more frequent in patients with preceding infection. Whether they predispose the individual for infection or infection increases the stroke risk in them needs to be examined.

Adult↗
PubMed1997

Anticardiolipin antibodies in ischemic stroke in the young: Indian experience.

Anticardiolipin antibodies (aCL) have been recognised as a marker for an increased risk of thrombosis. The prevalence of these antibodies in young Indian ischemic stroke population is not known. Our study establishes the prevalence of these antibodies and evaluates their clinical significance in 60 patients aged 40 years or less who presented with completed ischemic stroke. Immunoglobulin G and immunoglobulin M class antibodies to anticardiolipin were determined using a standardized enzyme-linked immunosorbent assay. The prevalence of these antibodies in stroke patients was 23% compared to 3.2% in the controls. All patients studied had no overt evidence of systemic lupus erythematosus or related autoimmune disorders. The aCL-positive stroke patients did not differ significantly from aCL-negative stroke patients with regard to demographic characteristics, risk factor profile, and radiological features. Prior transient ischemic attacks, ischemic retinopathy, and asymptomatic infection were more frequent in the aCL-positive group. The role of anticardiolipin antibodies as a disease marker for ischemic stroke is under-recognised in India and warrants further investigation.

Adult↗
PubMed1996

Case-control study of serum lipoprotein(a) and apolipoproteins A-I and B in stroke in the young.

OBJECTIVES: Abnormalities of lipoprotein(a) and apolipoproteins A-I and B are being recognised as independent risk factors in ischaemic heart disease and atherosclerosis. There are no studies from India where stroke in the young constitutes nearly 20-30% of all strokes. SUBJECTS AND METHODS: Fasting serum lipids, lipoproteins, apolipoproteins A-I and B and lipoprotein(a) were measured in 50 patients aged less than 40 years presenting with completed stroke and 50 normal, age and sex-matched control subjects. Apolipoproteins A-I and B were measured by immunoturbidimetry and lipoprotein(a) by enzyme-linked immunosorbent assay. RESULTS: The serum total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol, triglycerides and apolipoproteins A-I and B were not significantly different in the test group as compared to the controls. However, serum lipoprotein(a) was significantly higher in the young stroke patients. CONCLUSION: These findings confirm the hypothesis that an elevated serum lipoprotein(a) level is an important risk factor in the development of cerebral ischaemia in patients aged less than 40 years. It may be worthwhile to study whether it is useful in identifying patients most at risk for stroke.

Adolescent↗
PubMed1994

Biopsy of inoperable pancreatic tumors does not adversely influence patient survival time.

PURPOSE: To determine the influence of pancreatic biopsy on the survival times of patients with inoperable tumors of the pancreas. MATERIALS AND METHODS: One hundred seventy patients were examined; results of histologic analysis confirmed pancreatic malignancy in 119. The biopsy and nonbiopsy groups were comparable for age, sex, the presence of liver metastases, and nodal status. RESULTS: No statistically significant difference was demonstrated between the survival time for the biopsy group (median, 23 weeks) and that for the nonbiopsy group (median, 22 weeks). The estimated relative risk for death (biopsy group compared with nonbiopsy group) was 0.85 (95% confidence limits = 0.61, 1.18). CONCLUSION: Pancreatic biopsy does not appear to adversely influence survival time for patients with inoperable pancreatic tumors. Because histologic examination aids clinical management, biopsy should be part of the diagnostic work-up for patients with suspected inoperable pancreatic carcinoma.

Aged↗