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Biomedical subjects

A Perera

Publications and source records attributed to A Perera.

At least 37 records · Page 2Linked to original sources
PubMed1995

Brain single-photon emission tomography with technetium-99m hexamethylpropylene amine oxime in adolescents with initial-stage schizophrenia.

The objective of this study was to search for regional cerebral blood flow (rCBF) abnormalities in adolescents with initial-stage schizophrenia by means of brain single-photon emission tomography (SPET) using technetium-99m hexamethylpropylene amine oxime (HMPAO). SPET studies were performed on a homogeneous sample of 15 carefully selected adolescents with a recent diagnosis of schizophrenia, and without previous electroconvulsive or antipsychotic drug treatment. Computed tomography (CT) and electro-encephalographic (EEG) studies were performed in all patients. Qualitative and semiquantitative analysis of 99mTc-HMPAO SPET studies showed an impaired rCBF in 12 patients (80%). The most common pattern was a decreased uptake of 99mTc-HMPAO in the frontal lobes, usually in the left hemisphere. Conventional and quantitative EEG was positive in 12 (80%) and 15 (100%) patients, respectively. CT findings were positive in two patients (13%). There was a high level of concordance between SPET and EEG results and between SPET and clinical features (P>0.05). This study suggests that previously untreated patients in the first stages of schizophrenia present functional abnormalities that are revealed by brain SPET.

Adolescent↗
PubMed1995

A locally made mucus aspirator.

Examination of nasopharyngeal aspirate for the presence of viral antigens in children with acute lower respiratory tract infections is a standard procedure in establishing a viral aetiology. In the absence of other sophisticated methods such as lung puncture or trans-tracheal aspiration, mucopus aspirated from the nasopharynx can be used even to identify caustive organisms. Here, it is essential to perform a microscopic examination in addition to culture. The disposable mucus aspirators used in other countries are expensive and are not practical for routine use in our country. This paper describes how a mucus aspirator was turned out with low cost heat resistant materials that are locally available. The aspirator is steam sterilisable and can be used with a disposable F8 gauge feeding tube. The cost of one aspirator is about Rs. 100.

Humans↗
PubMed1992

A comparative binding of platinum anti-tumour compounds to plasma proteins in the rat (in vivo) and mouse (in vitro).

Plasma protein binding of 195mPt-labelled cisplatin, carboplatin and iproplatin has been studied in vivo in rat and in vitro in mouse, using both electrophoresis and trichloroacetic acid precipitation. After intravenous injection plasma clearance rates were biphasic for all 3 compounds, (t1/2 alpha, 13-17 min) but cisplatin was retained thereafter longer than the others. By 5 min, gel electrophoresis showed protein labelling with all 3 drugs but none involved low mol.wt. proteins (< 16 kDa). At 2 h a notable proportion of the protein bound platinum was associated with the latter components. There was a general resemblance between the distribution patterns of cisplatin and carboplatin whereas iproplatin showed a persistent retention of the label with time to higher mol. wt. proteins. From in vitro incubation with mouse plasma, rates of interaction respectively were cisplatin t1/2 alpha, 35 min, beta 8 h, carboplatin t1/2, 44 h and iproplatin t1/2, 104 h. By electrophoresis the protein bound fraction pattern (1 h) was again similar for cisplatin and carboplatin with virtually no binding to low mol. wt. proteins. After 24 h these were now involved to a high degree (40%). Iproplatin showed relatively marked binding to proteins of higher mol. wt. but no transfer with time to the low mol. wt. protein zone. A possible explanation is the need for in vivo metabolism for this compound as manifest in the rat. It is suggested that the significance of interaction with low mol. wt. proteins merits further investigation in relation to the antitumour and toxicological actions of these drugs.

Animals↗
PubMed1992

Therapy with fluconazole for tinea corporis, tinea cruris, and tinea pedis.

We treated 20 patients who had tinea corporis and/or tinea cruris and 20 patients who had tinea pedis with oral fluconazole. All patients were given a single 150-mg dose of fluconazole upon entry into the study; at that time, and at each follow-up visit, clinical signs and symptoms were evaluated and mycological and laboratory examinations were performed. If clinical and/or mycological cure or significant improvement in a patient's condition was not evident at the 7-day follow-up visit, a second dose of fluconazole (150 mg) was given. A maximum of four doses, one week apart, were given. A long-term evaluation of the efficacy of fluconazole in the treatment of these infections was performed 28-30 days after the last dose was administered to each patient. For the treatment of tinea corporis and/or tinea cruris, 70% of patients required two doses, 20% required three doses, and 10% required four doses. At the long-term follow-up visit the clinical and mycological response rates were determined to be 95% cure and 5% relapse. For the treatment of tinea pedis, 20% of the patients required two doses, 20% required three doses, and 60% required four doses. For these patients, the long-term clinical response rates were 70% cure and 30% improvement; mycological response rates were 75% eradication, 10% persistence of infection, and 15% relapse. This treatment was well tolerated; no adverse effects or clinically significant laboratory abnormalities were reported.

Administration, Oral↗
PubMed1991

Variation in hypothalamic gonadotrophin-releasing hormone content, plasma and pituitary LH, and in-vitro testosterone release in a long-distance migratory bird, the garden warbler (Sylvia borin), under constant photoperiods.

Changes in concentrations of hypothalamic gonadotrophin-releasing hormone (GnRH), pituitary and plasma LH, testicular mass, in-vitro release of testosterone, body mass and migratory activity were measured in male garden warblers (Sylvia borin) kept from November to June under a constant photo-period of 12.8 h. Under such conditions garden warblers gradually change from the photorefractory to the photosensitive state and gonadal recrudescence then occurs. Hypothalamic GnRH content was low from December to March, but increased in April to reach the highest levels in June. The spontaneous increase in GnRH was paralleled by increases in pituitary LH content, testicular mass and in-vitro testosterone release. Body mass decreased 1 month and nocturnal activity 2 months before the spontaneous increase in GnRH. Ovine LH increased in-vitro testosterone release over basal release at all times. The results suggest that in garden warblers (1) changes in hypothalamic GnRH content can occur under constant photoperiodic condition, (2) the gradual change from the photorefractory to the photosensitive state is not characterized by a gradual increase in hypothalamic content of GnRH (cf. starlings), and (3) Leydig cells are capable of testosterone release even during the photorefractory state.

Animals↗
PubMed1989

Counterion diffusion in heparin solutions.

The physiological importance of heparin is due to its strong interaction with bivalent counterions, especially Ca2+. A diffusional approach of this property is presented in this article: the observable is the self-diffusion coefficient of the counterions, as a function of the ratio of the polyelectrolyte over the added salt concentrations. All the results are in agreement with a simple "quasi-chemical model" in which two different states are assumed for the counterions: "free" or "bound." The proportions of these two types of ions are calculated according to the distribution function of the counterions around the polyion. We assume that those of counterions located at a distance closer than a, the characteristic distance, are bound; the others are free. The ionic distribution function is evaluated by a numerical integration of a cell model Poisson-Boltzmann equation. Finally, this model leads to a very good agreement with the experimental results, if the radius of heparin polyion is assumed to be 6 and 10 A.

Diffusion↗
PubMed1989

Failure of repeated blood patch in the treatment of spinal headache.

The management of a persistent, incapacitating postdural puncture headache that required four consecutive autologous epidural blood patches is presented. Inadequate blood volumes, early patching and steroid in the epidural space are considered as possible causes of failure. Other associated problems and interventions are briefly discussed.

Adult↗
PubMed1988

An autoradiographic study of the intrarenal localisation and retention of cisplatin, iproplatin and paraplatin.

The intrarenal localisation of platinum following the intravenous administration of platinum-195m-labelled cisplatin, iproplatin and paraplatin was studied using autoradiography. Following injection of cisplatin, platinum was distributed throughout the kidney even up to 14 days after treatment. In the case of iproplatin and paraplatin rapid platinum clearance was noted from the glomeruli, blood vessels and renal medulla within 2 h of administration. Relative cortical and medullary platinum radionuclide concentrations for all three agents were determined by Chalkley grid analysis. This showed greater relative concentrations of platinum in the cortex at increasing times following iproplatin and paraplatin compared with cisplatin. It is suggested that the lower renal toxicity of iproplatin and paraplatin than of cisplatin may be due to reduced platinum retention within the pars recta.

Animals↗