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Biomedical subjects

A Khan

Publications and source records attributed to A Khan.

At least 487 records · Page 27Linked to original sources
PubMed1988

Teratogenicity of n-propanol and isopropanol administered at high inhalation concentrations to rats.

As part of a teratological evaluation of several alcohols, 10,000, 7000 and 3500 ppm n-propanol or isopropanol were administered by inhalation to groups of 15 pregnant Sprague-Dawley rats for 7 hr/day on gestation days 1-19. The dams were killed on day 20. Half of the foetuses were examined for skeletal defects and the others for visceral defects using the Wilson technique. The highest concentration of n-propanol produced only minimal maternal toxicity, as indicated by observation and by measurement of weight gain and feed and water intake. In contrast, the same concentration of isopropanol produced narcosis in the dams, retarded body-weight gain and reduced the feed intake. At 7000 ppm isopropanol, body-weight gain was retarded but there were no other observable effects in the dams. Following exposure to 10,000 ppm of either alcohol, there were significant (P less than or equal to 0.05) increases in resorptions and decreases in foetal weights compared with the control groups. Foetal weights were also reduced significantly following exposure to 7000 ppm of either alcohol and to 3500 ppm isopropanol. Significantly more litters had malformations following exposure to 10,000 or 7000 ppm of either alcohol, but these effects were seen only in the presence of maternal toxicity. At 3500 ppm, no detectable teratogenic effects were produced by either solvent.

1-Propanol↗
PubMed1988

Preoperative localization of parathyroid adenomas.

During a 12-month period, 64 patients were operated on for primary hyperparathyroidism. Sixty-one had single adenomas and 3 had double adenomas. Preoperative imaging was used to localize the adenomas. Half of the patients (32 of 64) had magnetic resonance, thallium-201/technetium-99m subtraction scintigraphy, and high-resolution ultrasonography; the other 32 patients had 1 or 2 of the imaging modalities. Sensitivity and specificity of magnetic resonance imaging was 82 percent and 97 percent, respectively; the sensitivity and specificity of the other two modalities was 59 and 98 percent for subtraction scintigraphy and 73 and 98 percent for ultrasonography. The use of preoperative imaging facilitated surgical exploration, reduced operating time, and resulted in an increased number of successful operations. There were no negative explorations in this series as compared with 19 negative explorations (2.6 percent) in our prior experience with 720 operations.

Adenoma↗
PubMed1988

Optimization of computed tomography technique to demonstrate the fine structure of the lung.

The purpose of this investigation was to optimize the reconstruction algorithm and the slice thickness of computed tomography (CT) for the study of the fine structure of the lung. In 75 patients, we performed routine thoracic CT examination and obtained two high-resolution CT (HRCT) slices at the same level using the standard and bone algorithms, or using the slice thickness of 1.5 mm and 3.0 mm. Side-by-side comparison of the standard and bone images revealed that more branching of the small vessels and more small bronchi could be recognized on the bone image than on the standard image. Thickened bronchovascular bundles and interlobular septa were demonstrated more clearly on the bone image than on the standard image. There was no significant difference in the CT attenuation value between the standard and bone images. The difference between 1.5 mm and 3.0 mm images when demonstrating the small vessels and bronchi was minimal in such lesions as lymphangitis carcinomatosa and radiation fibrosis. Thus HRCT, with a slice thickness of 1.5 mm and 3.0 mm reconstructed by the bone algorithm, is suitable for the demonstration of the fine structure of the lung.

Humans↗
PubMed1988

Molecular cloning of 3-phenylcatechol dioxygenase involved in the catabolic pathway of chlorinated biphenyl from Pseudomonas putida and its expression in Escherichia coli.

Genes encoding 3-phenylcatechol dioxygenases were cloned from the chlorobiphenyl-degrading Pseudomonas putida strain OU83, using broad-host-range cosmid vector pCP13. Restriction enzyme analysis of DNA from 2,3-dioxygenase-positive chimeric cosmids showed DNA inserts ranging in size from 6.0 to 30 kilobases. The origin of the DNA insert in hybrid clones was established by using 32P-labeled hybrid clones (pOH101 and pOH810). A 2.3-kilobase HindIII fragment was common to two clones. The 2,3-dioxygenase from the parent P. putida strain, OU83, and the recombinant clones (pOH101 and pOH8101) showed similar characteristics as determined by isoelectric focusing and polyacrylamide gel electrophoresis. The 2,3-dioxygenase from the Escherichia coli recombinant cosmid showed a pI of 5.0, a Km of 14 microM, and broad substrate activity with catechol, 4-chlorocatechol, 4-methylcatechol, and 2,3-dihydroxybiphenyl.

Biodegradation, Environmental↗
PubMed1988

DST results in nonpsychotic depressed outpatients.

In two studies using the dexamethasone suppression test (DST) to evaluate the efficacy of newer antidepressants in depressed outpatients, the authors found a DST nonsuppression rate of 13% (11 of 86 patients). Thirty-three of the DST suppressors received an antidepressant and 42 received placebo; the drug-treated group showed a significant therapeutic response. The low rate of DST nonsuppression in these depressed outpatients, a finding consistent with that of other investigators, does not confirm or refute reports that these patients are relatively resistant to placebo in comparison with active medication. The authors recommend that DST results not be used as selection criteria in studies assessing newer therapies for depressed outpatients.

Adult↗
PubMed1988

Enhancement of cell-mediated cytotoxicity by recombinant tumor necrosis factor (TNF alpha).

The effects of recombinant tumor necrosis factor (rTNF alpha) on the immune responses were investigated. A single iv injection of rTNF alpha (6 x 10(3) U) caused regression of sarcoma-180 transplanted into BALB/c nu/+ mice, but failed to regress this tumor in nu/nu mice. A higher dose of rTNF alpha (2 x 10(4) U) was necessary to induce antitumor effect in nu/nu mice. A host-related factor seemed to be involved in mediating tumor regression. Therefore, the effects of rTNF alpha on various T-dependent immune responses, including delayed footpad reaction (DFR), cell mediated cytolysis (CMC), and plaque-forming cells (PFC) were examined in BALB/c mice, immunized ip with chicken erythrocytes (CRBC). A single injection of rTNF alpha, at the time of the antigen administration, induced the augmentation of CMC to CRBC in a dose-dependent manner. DFR and PFC were not affected in optimal immunization procedures. The TNF alpha injection, at or after the time of antigen administration, was more effective in inducing augmentation of CMC. The increase in CMC by TNF alpha was mediated by nonadherent, Thy 1.2, Lyt 2.2 positive cells and neutralization of TNF alpha by the anti-TNF alpha monoclonal antibody abolished the effect on CMC. These results indicated that the human recombinant TNF alpha induced changes in the T-cell-mediated responses.

Adjuvants, Immunologic↗
PubMed1988

Increased expression of adhesive proteins on leukocytes by TNF alpha.

To further elucidate the role of tumor necrosis factor alpha (TNF alpha) in cell adhesion, we investigated the effect of TNF alpha on the expression of surface adhesive protein. After treatment with TNF alpha for 1 h, the increased expression of surface adhesive proteins (beta subunit) was observed on granulocytes but not on monocytes or lymphocytes. The expression of Mac-1 (3,4-fold increase) was consistently enhanced more than p 150,95 (1.4-fold increase) and LFA-1 expression was unchanged. Dose-response and time course studies indicated a parallel relationship between TNF alpha-increased expression of surface adhesive proteins and TNF alpha-induced granulocyte adhesion. The anti-inflammatory drug Dexamethasone suppressed both TNF alpha-induced granulocyte adhesion and TNF alpha-induced expression of surface adhesive proteins. The inhibition of granulocyte adhesion correlated with the reduction of surface adhesive protein expression. The data suggest that one contributing factor in the mechanism by which Dexamethasone inhibited TNF alpha-induced granulocyte adhesion may be diminished expression of surface adhesive proteins.

Antigens, Surface↗
PubMed1988

Psychotic and nonpsychotic depression: comparison of response to ECT.

The charts of 46 patients who underwent ECT in a teaching hospital between 1980 and 1986 were reviewed. All patients were suffering from major depression, with or without psychotic features, and were resistant to pharmacotherapy. Response to ECT was compared between those with psychotic features (N = 27) and those without psychotic features (N = 19). Both groups had equal and effective response to ECT. Therefore, the presence of psychotic features was not significant in predicting response to ECT.

Delusions↗
PubMed1988

[Percutaneous transluminal balloon dilatation of discrete membranous subvalvular aortic stenosis].

Discrete membranous subaortic stenosis (DMSS) which is localized immediately subvalvular and can be differentiated from fibromuscular stenosis of the left ventricular outflow tract, represents theoretically a well-suited lesion for uncomplicated balloon dilatation. The practical use of balloon dilatation for treatment of DMSS has been reported by two groups [6, 10]. In this overview, we will report our experience with balloon dilatation of DMSS in six children. Between June, 1986 and June, 1987, balloon dilatation of DMSS was carried out in six male children ranging in age from four to ten years (Table 2). In one child, coarctation of the aorta had been present and was previously treated successfully with balloon dilatation. In two children, the aortic valve was thickened with or without stenosis. All children had mild aortic regurgitation. After transvenous right heart catheterization and transarterial left heart catheterization including levocardiography and supraaortic angiography, 50 units of heparin per kilogram of body weight were administered and a guidewire advanced to the left ventricle for positioning of the balloon catheter in the left ventricular outflow tract. The choice of balloon diameter was based on measurement of the angiographically-determined aortic ring diameter (Table 1). Pressure measurements were obtained by means of a diagnostic catheter after the dilatation. No complications were observed either during or immediately after the intervention. After the dilatation, all children were discharged from the hospital to go home. Pressure in the left ventricle was reduced from 225 +/- 55 to 116 +/- 29 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Stenosis, Subvalvular↗
PubMed1988

[Percutaneous transvenous antegrade balloon angioplasty in aortic isthmus stenosis].

Balloon angioplasty of native or postoperative coarctation of the aorta has been recommended as an alternative method to surgical treatment. On use of the retrograde approach via the femoral artery, after introduction of the catheter into a vessel of narrow lumen, not infrequently, injury or obstruction was observed. This overview summarizes our experience primarily on use of antegrade balloon angioplasty for coarctation of the aorta, the first description of which was published as a case report in 1986. Between December, 1985, and September, 1987, balloon angioplasty was carried out for native coarctation of the aorta in seven neonates, age two to 30 days. Concomitant cardiovascular anomalies included ventricular septal defect in five, patent ductus arteriosus in five, mitral valve atresia in two and transposition of the great arteries with and without double outlet right ventricle in two (Table 1). Prior to balloon angioplasty for coarctation, in four neonates therapeutic balloon atrial septostomy had been performed. For balloon angioplasty, via the right femoral vein, an end-hole catheter was advanced into the right ventricle. In five neonates, the catheter could be advanced into the ascending aorta directly from the right ventricle or through a ventricular septal defect. In the two other neonates, the catheter was advanced via the foramen ovale and the mitral valve into the left ventricle and the ascending aorta. Pressure was measured by the end-hole catheter as well as in the femoral artery after direct puncture.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Coarctation↗
PubMed1988

Plagioporus gonii nov. spec. (Trematoda: Opecoelidae) from the fish Labeo gonius of Kalri Lake, Sind, Pakistan.

A new trematode, Plagioporus gonii sp. n., is described from the fish Labeo gonius of Kalri Lake, Sind, Pakistan. This species is characterized by possessing round, subterminal oral sucker; small prepharynx; pharynx subglobular; oesophagus short; acetabulum larger than oral sucker; caeca simple; testes subspherical to irregular in shape; ovary irregular in shape; vitellaria rounded, follicular, extending little behind intestinal bifurcation to the end of the body, interrupted on one or both sides at the level of the acetabulum; cirrus sac preacetabular; genital pore posterior to intestinal bifurcation; and eggs 0.071-0.078 by 0.033-0.042 mm in size.

Animals↗
PubMed1987

Metastatic neuroblastoma after 52 years of dormancy.

A metastatic neuroblastoma arose in a posterior mediastinal tumor that had been present for at least 52 years. The diagnosis of neuroblastoma was first made when the patient was 81 years of age from biopsy of a metastatic lesion to the femur and later from biopsy of the mediastinal mass.

Aged↗
PubMed1987

Purification of a kappa-opioid receptor subtype from frog brain.

A kappa-opioid receptor subtype was purified from a digitonin solubilized preparation of frog brain membranes using affinity chromatography. The affinity resin was prepared by coupling D-Ala2-Leu5-enkephalin to Sepharose-6B matrix. After elution of the receptor by 50 mumol naloxone, the kappa-subtype was separated from the mu- and delta-subtypes by gel permeation chromatography on Sepharose-6B. The purified receptor binds 3,900 pmol [3H]-ethylketocyclazocine per mg protein (a 4,300-fold purification over the membrane-bound receptor) with a KD of 8.3 nM. The purified receptor protein exhibits high affinity for kappa-selective ligands. The purified fraction shows two bands (Mr 65,000 and 58,000) in sodium dodecyl sulfate gel electrophoresis.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1987

Mitral valve abnormalities and catecholamine activity in anxious patients.

We studied 38 anxiety disorder patients, 19 of whom had evidence of mitral valve abnormalities by two-dimensional echocardiography. The presence or absence of mitral valve abnormalities was not related to 3-methoxy-4-hydroxyphenylglycol/creatinine excretion, platelet and plasma monoamine oxidase-type activity, or autonomic arousal as measured by blood pressure and resting heart rate. These findings fail to support the hypothesis that mitral valve abnormalities identify a specific subpopulation of anxious patients with differences in catecholamine function.

Adult↗