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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 1,261 records · Page 70Linked to original sources
PubMed1993

Pulmonary vascular disease in neonates with transposition of the great arteries and intact ventricular septum.

BACKGROUND: Progressive pulmonary vascular disease in surgically unrepaired transposition of the great arteries with or without ventricular septal defect had been frequently described in the past. Occurrence of progressive pulmonary vascular disease has been reported even after atrial switch procedure done at three months of age. With the advent of neonatal surgical repair, this problem is virtually non-existent. There is a small subgroup of infants with transposition of the great arteries who show pulmonary vascular disease in the neonatal period that can adversely affect the surgical outcome. The clinico-pathological correlation in this group of patients was studied. OBSERVATIONS: Three patients, with transposition of the great arteries and intact ventricular septum, who showed histological evidence of pulmonary vascular disease in the neonatal period or early infancy are described. Two of these patients, continued to have poor systemic oxygenation despite adequate atrial communication. One patient had a close ductus arteriosus within the first two hours of birth while on prostaglandin E1 infusion. CONCLUSIONS: In the absence of left ventricular outflow tract obstruction, a poor response to atrial septostomy suggests pulmonary hypertension and pulmonary vascular disease. Antenatal constriction of the ductus arteriosus may contribute to such changes in pulmonary vasculature.

Female↗
PubMed1993

Reductions in parietal and temporal cerebral metabolic rates for glucose are not specific for Alzheimer's disease.

Reduction in the regional cerebral metabolic rate for glucose (rCMRglc) in the parietal and temporal regions has been shown in Alzheimer's disease (AD). The specificity of these findings for this disease state is uncertain. We repeatedly measured rCMRglc with positron emission tomography and [18F]2-fluoro-2-deoxy-D-glucose in the resting state in a 68 year old man with slowly progressive dementia who, during life, was initially diagnosed as having dementia of the Alzheimer type, then Parkinson disease with dementia, but was found to have only Parkinson's disease at necropsy. Metabolic ratios (rCMRglc/mean grey CMRglc) were significantly (p < 0.05) reduced in parietal and temporal regions, as well as in the prefrontal and premotor areas. This pattern was similar in regional distribution and magnitude of the defect to that seen in patients with probable AD. These results suggest that reductions of glucose metabolism in association neocortex in AD are not specific to the disease process, but may be related to the dementia state.

Aged↗
PubMed1993

Monoclonal antibodies against farmer's lung antigens having specific binding to IgG antibodies.

Hypersensitivity pneumonitis resulting from environmental exposure to Saccharopolyspora rectivirgula (Micropolyspora faeni) among farmers has been well recognized. The diagnosis of the disease depends on demonstration of circulating antibodies against S. rectivirgula. However, dependable pure antigens are not available for serodiagnosis. In the present study we have employed hybridoma technology to obtain monoclonal antibodies against S. rectivirgula antigens. These monoclonal antibodies were employed to purify antigens through affinity chromatography. When tested in ELISA, high levels of antibodies were demonstrated against these antigens in farmer's lung patient sera compared to exposed but asymptomatic individuals from the same household. In Western blots patient sera reacted with components of crude antigens with molecular masses of 28, 35, 60, 65 and 68 kD and 4 components above 100 kD, while the monoclonal antibodies reacted only with the 60-kD protein. These purified antigens can be used as reliable reagents in the specific diagnosis of farmer's lung disease.

Animals↗
PubMed1993

Population pharmacokinetics of ceftizoxime in premature newborns.

The population pharmacokinetic parameters of ceftizoxime were determined in 50 premature newborns less than 1 week of age (birth weight = 1.8 +/- 0.6 kg) with a clinical diagnosis of suspected sepsis. Each infant received ceftizoxime 25 mg/kg every 12 h intravenously over 30 min for a total of 6 doses. Serum concentrations of ceftizoxime were assayed by HPLC at 0.5, 1, 2.5 and 11.5 h or at 0.5, 1.5, 4.5 and 11.5 h after the first and the sixth dose. A total of 184 serum concentrations following the first dose and 160 following the sixth dose were fit separately and then collectively to a one-compartment model using NONMEM. The separately estimated parameters were not significantly different between the first and the sixth dose. The final parameter estimates were 27.1 ml/h/kg, 333 ml/kg and 8.5 h for clearance, volume of distribution and half-life, respectively. Other factors including gestational and postnatal age were not associated with alterations in ceftizoxime clearance. That the large variability in clearance was decreased from a coefficient of variation of 80 to 50% warrants dosing premature infants on the basis of body weight. The results of this study suggest that 25 mg/kg ceftizoxime every 12 h appears to be an appropriate dosing regimen for premature neonates.

Ceftizoxime↗
PubMed1993

Analysis of clinical and laboratory profile in Indian childhood systemic lupus erythematosus and its comparison with SLE in adults.

Data on the clinical and laboratory profiles of 83 children with SLE have been analysed and compared with data on 187 adults with the disease. The clinical features of childhood SLE are similar to those seen in adults, although clinical and laboratory parameters reflect propensity to a more severe form of the disease in the juvenile age group. However, in comparison to descriptions of childhood lupus from developed countries, in India the female-to-male ratio in this age group parallels that in adults. Renal involvement is noted to be more common, whereas gastro-intestinal and haematological abnormalities are less common. Interestingly, leucopenia, lymphopenia and nephritic type of renal involvement are commonly seen in boys with SLE, but these features are non-existent in men.

Adolescent↗
PubMed1993

Prevalence of systemic lupus erythematosus in India.

Prevalence of systemic lupus erythematosus (SLE) was studied in the northern Indian population by means of a two-pronged approach: (a) antinuclear antibody (ANA) screening of the general population by a new well-standardized finger-prick 'filter paper' technique (sensitivity and specificity: 95.4% and 86.2%, respectively); and (b) a questionnaire survey carried out primarily by trained personnel in the community (sensitivity and specificity: 100% and 68.6% respectively). The low specificity of the two methods was improved by the introduction of a step of secondary screening by the authors, thus excluding false positives. ANA screening of 52,062 individuals yielded 13 positive results, of which only two were found to be true cases of SLE after secondary screening. Questionnaire survey of 39,826 individuals similarly yielded 3393 positive results. On secondary screening, only one of these persons was found to be a case of SLE. Thus, three cases of SLE were detected in a population survey of 91,888, giving a point prevalence of 3.2 per 100,000 (95% CI = 0-6.86 per 100,000). The reported prevalence of SLE ranges from 14 to 60 per 100,000. Thus, the prevalence of SLE in India is comparatively low. Although the reasons for low prevalence are not clear, the study used highly sensitive methodology and it is therefore unlikely that SLE cases were missed. It is hypothesized that SLE is a disease of modernization and therefore its prevalence in a predominantly rural population like that of India is low.

Antibodies, Antinuclear↗
PubMed1993

Major histocompatibility complex genes and susceptibility to systemic lupus erythematosus in northern India.

Fifty-eight patients with systemic lupus erythematosus (SLE) from Northern India were tissue typed for HLA class I and II antigens. The results revealed an appreciable increase of HLA-DR4 (37.5%) among patients compared with controls (17.9%), P < 0.03. Additionally, haplotype B8-DR3 was encountered frequently in the patient group. The findings suggest an important role of MHC genes in influencing susceptibility to SLE.

Adolescent↗
PubMed1993

Posterior fossa surgery: an unusual cause of superficial siderosis.

With the widespread use of magnetic resonance imaging, an increasing number of cases of superficial siderosis are being discovered. However, the cause remains uncertain in almost half the cases. We report a case where previous surgery for a pontine hematoma established a pathway for extravasation of blood into the 4th ventricle, resulting in superficial siderosis that was demonstrated on a follow-up magnetic resonance imaging scan 8 years later. This case presents an unusual iatrogenic cause of superficial siderosis that has not been reported previously.

Brain Neoplasms↗
PubMed1993

Radiosensitization of human lung fibroblasts by chemical that decrease ATP levels.

Radiosensitization by lactate, pyruvate, nalidixic acid and novobiocin was studied in exponentially growing SH-18L human lung fibroblasts. All the chemicals had a slight radiosensitizing effect at a low concentration and a definite effect at a higher one. Decreases in the D0 and/or Dq values were present in each dose survival curve. Fibroblasts incubated with the low concentration of each chemical for 24 hrs after X irradiation showed no reduction in intracellular ATP content, whereas, the higher concentration produced a significant decrease. These observations suggest that the decrease in the ATP content may be involved in the radiosensitization of human fibroblasts at high concentrations of these chemicals. In contrast, radiosensitization at a low concentration is not explained by a relationship to ATP content. Different mechanisms may be involved in radiosensitization at low and high concentrations of these chemicals.

Adenosine Triphosphate↗
PubMed1993

Rebound caloric nystagmus.

Rebound caloric nystagmus (RCN), a distinctly different phenomenon from secondary phase nystagmus (SPN), was serendipitously discovered during the course of routine neurotological evaluations. RCN occurred when the horizontal semicircular canal was brought into a truly horizontal plane after the primary phase nystagmus (PPN) had ended. The maximum slow-phase velocities (SPVMax) of both PPN and RCN were almost identical. The pathological lesion was an Arnold-Chiari malformation (ACM). Two other patients with posterior fossa lesions also showed RCN. To determine if RCN is an unrecognized normal phenomenon, 11 healthy subjects were tested. The average SPV of RCN in normals was 0.7 degrees per second. Such a small value of RCN is probably of no significance. It therefore appears that RCN is a sign of posterior fossa neuroaxial lesions.

Adult↗
PubMed1993

The mystery ingredients: sweeteners, flavorings, dyes, and preservatives in analgesic/antipyretic, antihistamine/decongestant, cough and cold, antidiarrheal, and liquid theophylline preparations.

OBJECTIVE: Pharmaceutical preparations may contain a variety of excipients ("inert ingredients"). These excipients are generally inactive; however, rare adverse effects caused by excipients have been reported. Information about the excipients in a particular preparation is not readily available. METHODS: The information about sweeteners, flavorings, dyes, and preservatives for the chewable and liquid preparations of over-the-counter and prescription products of antidiarrhea, cough and cold, antihistamine/decongestant, analgesic/antipyretic, and liquid theophylline medications was collected. RESULTS: Information about excipients in 102 chewable and liquid preparations was compiled. An average preparation contained two sweeteners. Saccharin and sucrose were the most common sweeteners found--each was present in 52 preparations--followed by sorbitol, glucose, fructose, and others. For 36 of the 102 preparations, type of flavoring was not specified. In the remaining preparations, cherry was the most common flavoring, followed by vanilla and lemon. Twenty-one different dyes and coloring agents were used. Red dye No. 40 was the most common (42/102), followed by yellow No. 6 (27/102). Of the eight preservatives used, sodium benzoate and methylparabens were present in 42 and 27 of the preparations, respectively. Tables detailing these excipients and adverse effects reported are presented. CONCLUSIONS: The tables should be helpful to physicians in selecting preparations containing different excipients when an adverse reaction occurs. The mandatory labeling of excipients in all pharmaceutical preparations is the only way that physicians and patients can be fully informed.

Analgesics↗
PubMed1993

Effect of sodium valproate on serum amylase in epileptics.

Thirty-eight patients of generalised tonic-clonic seizures of epileptics in the age group of 15-30 years were included in this study. Of these 20 were started sodium valproate afresh and 18 already taking it for more than one year prior to inclusion. Serum amylase and serum valproic acid levels were measured in all of them, initially and at every 3 months interval for 9 months. Though no clinical evidence was present, there was significant increase in serum amylase levels in both the groups which has no correlation with dose or serum valproic acid levels.

Adolescent↗
PubMed1993

Acute non-lymphocytic leukemia with expression of surface antigen CD7--morphological, cytochemical, immunological and ultrastructural features in eight patients.

Of late, there has been an increase in the number of acute leukemias coexpressing markers believed to be restricted to a single lineage. Eight patients with ANLL whose blast coexpressed the T cell associated CD7 antibody were identified among 462 consecutive ANLL cases. Seven had FAB defined AML according to morphocytochemical criteria, whereas one patient was classified as MO on the basis of ultrastructural studies. The incidence of CD7 positivity was particularly significant in the less differentiated sub-types MO and M1 compared to other FAB sub-groups. Detailed long term studies will be required to realize their biological and clinical significance.

Adolescent↗
PubMed1993

Multiple CCAAT binding proteins regulate the expression of the angiotensinogen gene.

Angiotensinogen is a serum glycoprotein which is primarily synthesized in the liver and converted into the octapeptide hormone angiotensin-II in circulation. Transient transfection studies have identified a cis-acting DNA element located between 115 and 145 bp upstream from the transcriptional initiation site in the promoter of the rat angiotensinogen gene which is involved in the regulation of its transcription. This region of the promoter has sequence homology with NF-1/CCAT, C/EBP, and CP1 binding sites. We show here by DNase-I footprint and gel shift assay in presence of recombinant transcription factors and their antibodies that NF-1/CAAT and C/EBP like transcription factors bind to this region of the promoter. Our DNase footprint assay with recombinant NF-1/CAAT has also identified another NF-1 binding site between -180 and -190. Since our previous studies have identified a NF-1 site in the proximal promoter region and two C/EBP binding sites in the distal promoter region of the angiotensinogen gene, our data suggests that multiple CAAT binding factors regulate the expression of the angiotensinogen gene in liver cells. In accordance with these results, we show that cotransfection of mammalian expression vectors containing NF-1/CAAT or C/EBP coding sequence increases the promoter activity of the angiotensinogen gene in human hepatoma cells.

Angiotensinogen↗