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Biomedical subjects

A Kumar

Publications and source records attributed to A Kumar.

At least 1,549 records · Page 86Linked to original sources
PubMed1990

Synthetic, immunological and structural studies on repeat unit peptides of Plasmodium falciparum antigens.

Using solid phase methodology, we have synthesized five peptides (16-18 residues long) corresponding to repeat sequences of four antigens of a human malarial parasite, Plasmodium falciparum. Three of these antigens (RESA, FIRA, and ABRA) are found in the asexual blood-stages of the parasite, while the remaining one (CSP) is found in the sporozoites. The synthetic peptides, conjugated to bovine serum albumin, elicited high levels of antibodies in rabbits, and these antibodies were found to cross-react with the heterologous peptides. The degree of cross-reactivity, as estimated in an ELISA, was quite remarkable among all the peptides. The peptide corresponding to the RESA tetrapeptide repeat was found to be the most immunogenic and highly cross-reactive. For this reason this tetrapeptide repeat unit, peptide 1, may be a suitable candidate for inclusion in a multiple epitope polypeptide vaccine design. Conformational studies using circular dichroism spectroscopy show that these peptides have similar conformational characteristics with a common feature of approximately 30% and approximately 50% helical content water and TFE respectively. Theoretical predictions regarding conformation using the Chou-Fasman method have also been presented.

Amino Acid Sequence↗
PubMed1990

Bilateral angiosarcoma of the breast: an overview.

Angiosarcoma of the breast is a rare and aggressively malignant tumour. A case of a young lady presenting with bilateral mammary angiosarcoma and associated pregnancy is reported. Only one such case is documented in the literature. Existing literature is also reviewed. The often deceptively benign histological appearances which are extremely variable demand serious suspicion of angiosarcoma when confronted with an angiomatous lesion of the breast. Early and complete surgical excision is the treatment of choice, and adjuvant chemotherapy may have a role in the treatment. Histological grading is the most important prognostic factor with poor grades having an unfavourable outlook.

Adolescent↗
PubMed1990

Chromosomal localization and copy number of 18S + 28S ribosomal RNA genes in evolutionarily diverse mosquitoes (Diptera, Culicidae).

In situ hybridization using 3H-labeled 18S and 28S ribosomal DNA (rDNA) probes from Aedes albopictus was performed on the mitotic chromosomes of 20 species of mosquitoes belonging to 8 genera of subfamilies Culicinae and Anophelinae. In all but one species examined, the rDNA family was localized to a single chromosome per haploid genome. Aedes triseriatus was the only exception, with the rDNA cistrons present on chromosome 1 and on chromosome 3. The ribosomal RNA genes were located on chromosome 1 in Ae. albopictus, Ae. aegypti, Ae. flavopictus, Ae. seatoi, A. polynesiensis, Ae. alcasidi, Ae. annandalei, Ae. mascarensis, Ae. hendersoni, Ae. atropalpus, Ae. epactius, Culex pipiens quinquefasciatus, Wyeomyia smithii, and Sabethes cyaneus; chromosome 2 in Ae. mediovittatus and Haemagogus equinus; chromosome 3 in Armigeres subalbatus and Tripteroides bambusa; and the heteromorphic X and Y chromosomes in Anopheles quadrimaculatus. The variation in the location of ribosomal RNA genes on the different chromosomes and at different positions on the chromosome arm among the mosquito species examined is suggestive of considerable chromosome repatterning through translocations and inversions in the karyotypic evolution of mosquitoes. Dot-blot hybridization was used to estimate copy number of rRNA genes; the copy number per haploid genome ranged from 39 +/- 3.27 in Sa. cyaneus to 1023 +/- 68.14 in Ae. flavopictus.

Animals↗
PubMed1990

Orbital cysticercosis--an ultrasonic diagnosis.

Ocular cysticercosis, a platyhelminth infection, involves various ocular and adnexal sites. Orbital cysticercosis is a relatively rare site of presentation. We illustrate that this parasitic cyst, when present in the orbit, mimics an orbital pseudotumour. We have used ultrasound as an effective pre-operative diagnostic modality.

Adult↗
PubMed1990

Virological investigations of acute encephalopathy in India.

A total of 740 consecutive children aged between 6 months and 12 years who presented with acute encephalopathic illnesses during a three year period were assessed both clinically and by laboratory investigations. Cerebrospinal fluid was examined for the presence of cells or other abnormal substances, and any organisms were cultured. Blood examination included white cell count and estimations of haemoglobin, urea, glucose, and electrolyte concentrations and serum alanine aminotransferase and aspartate aminotransferase. A firm diagnosis was established in 278 patients (38%). Pyogenic meningitis (n = 134), measles encephalopathy (n = 38), and electrolyte imbalance (n = 23) were important causes in this group, cerebral malaria (n = 4) was uncommon and there were no cases of Reye's syndrome. The diagnoses of the remaining 462 were combined under the heading 'acute unexplained encephalopathy'. Altogether 394 of the 462 patients underwent virological investigations for arboviruses and 92 (23%) had one or more indicators of Japanese encephalitis. No other arboviruses could be isolated. Throat swabs from 187 patients with acute unexplained encephalopathy were studied on monkey kidney tissue cell lines of which 14 were positive (8%). These were identified as adenovirus, parainfluenza, influenza, poliomyelitis, Coxsackie, and echovirus; in two cases the virus was untypable. Japanese encephalitis is an important cause of acute childhood encephalopathy in this region. Clinical features of the illness may be mimicked by several disorders which require specific treatment. Thirty four of the 92 died (37%).

Acute Disease↗
PubMed1990

CT and MR imaging of intralabyrinthine schwannoma: report of two cases and review of the literature.

Two cases of intralabyrinthine schwannoma were studied with computed tomography (CT) and magnetic resonance (MR) imaging. On CT scans, a soft-tissue mass was identified in the round window niche in both cases. Widening of the basilar turn of the cochlea and characteristic erosion of the promontory were noticed in one case. Preoperative MR imaging (performed in only one case) revealed a soft-tissue mass in the labyrnth, extending into the round window niche. Findings at CT and MR imaging are discussed, and a differential diagnosis is given. The literature is reviewed. The authors' findings suggest that CT and MR imaging may prove very valuable in the previously difficult preoperative diagnosis of these tumors. In the setting of progressive sensorineural hearing loss, atypical Meniere disease, or recurrent vertigo, the presence of a mass in the labyrinth or labyrinthine windows- delineated on CT or MR images, despite a normal internal auditory canal, cerebellopontine angle, or brain stem - is highly suggestive of intralabyrinthine schwannoma.

Aged↗
PubMed1990

Influence of desglycinamide-(arg8) vasopressin on memory in healthy subjects.

In 12 healthy student volunteers the influence on memory, attention and mood of a single dose of 2 mg of the vasopressin analog, desglycinamide-(arg8) vasopressin (DGAVP), given by the nasal route was investigated. On day 1 all subjects received placebo (single-blind), 1 week later they were given either DGAVP or placebo (double-blind). Memory effects were measured with the Buschke restrictive reminding method. DGAVP significantly improved storage processes, with retrieval processes less affected. Attention and mood processes were not influenced. It is suggested that DGAVP has an influence on memory processes.

Adult↗
PubMed1990

Subgroups in dementia of the Alzheimer type identified using positron emission tomography.

We examined patterns of cerebral glucose metabolism in 33 patients with dementia of the Alzheimer type by applying principal component analysis to identify subgroups. Four subgroups were identified: one with predominant parietotemporal hypometabolism (15 patients); one with paralimbic metabolic deficits (8 patients); one with left hemisphere neocortical abnormality (5 patients); and one with frontal and parietotemporal deficit (5 patients). Differences among the subgroups were found in neuropsychological impairments and prevalence of psychiatric symptoms. These metabolic subgroups could not be explained on the basis of dementia severity, illness duration, or age, but were most likely related to an underlying pathology with a variable regional distribution.

Aged↗
PubMed1990

Paracetamol overdose in children.

The severity of paracetamol poisoning varies but in general, children are considered less susceptible to its toxic effects compared to adults. In this report we describe the relatively benign ingestion of paracetamol in children and also highlight a case of intrauterine exposure to a potentially toxic dose of paracetamol.

Acetaminophen↗
PubMed1990

Cimetidine: an immunomodulator.

Suppressor T lymphocytes possess histamine2 (H2) receptors and contribute significantly to the function of the immune system. Experimentally, cimetidine, an H2-receptor antagonist, has been shown to enhance a variety of immunologic functions both in vivo and in vitro because of its inhibitory effects on suppressor-cell function. Successful tumor immunotherapy, as well as some protection from infection, has been reported in experimental animals. Patients receiving cimetidine have been shown to exhibit enhanced cell-mediated immunity as evaluated by increased response to skin-test antigens, restoration of sensitivity following development of acquired tolerance, and increased responses of lymphocytes to mitogen stimulation. Preliminary reports also indicate that cimetidine may offer therapeutic benefits for patients with Varicella zoster and Herpes simplex infections, as well as those suffering from mucocutaneous candidiasis and common variable hypogammaglobulinemia. These immunoregulatory effects are dose-related but are not always consistent. Because of its inhibitory effect on suppressor function, cimetidine treatment may be deleterious in patients with organ transplant and autoimmune disorders. Cimetidine should be used as an immunomodulator on an experimental basis only.

Adjuvants, Immunologic↗
PubMed1990

Intracavernous papaverine in the management of psychogenic impotence.

Intracavernous papaverine has found an important place in the management of male erectile failure. The effect of this mode of therapy was studied in 48 patients with psychogenic impotence. The average follow-up for this group of patients ranged from 7 months to 37 months (mean 16.3 months). All the patients in this group were advised sex therapy as an initial mode of therapy. On refusal to undergo sex therapy, they were offered an option of intracavernous papaverine injection. Papaverine appears to break the performance anxiety erectile failure cycle and was noted to have good results. Overall 57.9% patients expressed complete satisfaction with this mode of therapy. One patient (2.1%) developed priapism, which was adequately treated with intracavernous epinephrine. Use of low dosage of papaverine is suggested as an additional mode of therapy in the management of psychogenic impotence.

Adult↗
PubMed1990

Eosinophilic granuloma of the spine with neurological deficit.

A case of a 14-year-old boy with a solitary eosinophilic granuloma of the thoracic spine, with paraplegia secondary to the collapse of the vertebra and peridural spread of tumor, is presented. It is the 14th case recorded in literature to this date. This disease is self-limiting, and there is no role of steroids or radiotherapy observed.

Adolescent↗
PubMed1990

Intraventricular morphine for intractable craniofacial pain.

This case management report on a patient with advanced craniofacial neoplasm discusses the successful treatment of chronic pain by the cortical intraventricular narcotic administration. A previously treated patient with surgery and radiotherapy for carcinoma of the palate developed severe intractable pain despite high dose oral morphine therapy. Investigations revealed that neoplasm had reoccurred with extensive infiltration. Intraventricular morphine therapy was discussed and accepted by the patient and family. A ventricular shunt with an Ommaya reservoir was inserted under local anaesthesia. Preservative-free morphine sulphate in increasing doses of 0.25 to 1 mg was administered, once daily, which kept the patient in a pain-free state. The treatment was initiated in the hospital and continued at home till the demise of the patient on the 9th week. The home care was provided by the nurses of Home Nursing Foundation and Singapore Cancer Society under physician supervision. There were no complications which had been reported in the literature, observed in the management of this patient.

Drug Administration Schedule↗