Search PubMed⌕ Search

Biomedical subjects

S Abraham

Publications and source records attributed to S Abraham.

At least 145 records · Page 8Linked to original sources
PubMed1989

Clastogenic effects produced by black pepper in mitotic cells of Vicia faba.

Black pepper, as is well known, is an important spice widely used in the cooking and processing of meat and fish. The aim of the present investigation was to evaluate the clastogenic potential of black pepper. This was accomplished by treating root meristems of Vicia faba with aqueous extracts of black pepper. Examination of the treated roots showed the presence of chromatid breaks, chromosome breaks, gaps and exchanges. Statistically significant differences from controls were observed. Experiments to evaluate its clastogenic potential in mouse systems are in progress and the results will be published elsewhere.

Animals↗
PubMed1989

Using a phonological framework to describe speech errors of orally trained, hearing-impaired school-agers.

A phonological framework was used to analyze and describe the meaningful speech and speech errors of 13 orally trained, hearing-impaired children ages 5:11 to 15:11 enrolled in public school programs. Using speech samples elicited from the subjects, consonant inventories and percentage scores for correct production of consonants and for frequency of occurrence of phonological processes were derived and analyzed. Results of data analyses indicated initial consonant inventories were significantly larger and more complete than final inventories, although both were incomplete. Production accuracy for consonants in the subjects' inventories was significantly related to size of consonant inventories. Accuracy of production differed significantly between sound classes and word positions. Between 4 and 9 phonological processes were productive and co-occurring in the hearing-impaired subjects' meaningful speech. Comparisons with younger, normal hearing children and phonologically disabled children are drawn, and the clinical implications of the findings are discussed.

Adolescent↗
PubMed1989

Mechanisms underlying the antiarrhythmic properties of beta-adrenoceptor blockade against ischaemia-induced arrhythmias in acutely prepared rats.

1. The mechanism underlying the limited antiarrhythmic effects of beta-adrenoceptor blocking agents against occlusion-induced arrhythmias in acutely prepared, pentobarbitone-anaesthetized rats has been investigated. 2. Atenolol, ICI 111,581 and propranolol were given at low, medium and high doses calculated to shift dose-response curves to exogenous agonists by factors of 10-30, 100-300 and 1000-3000, respectively. 3. Arrhythmias, blood pressure, heart rate, ECG changes and serum K+ were measured. 4. Antiarrhythmic activity was seen with beta-blocker treatment. This was minimal with atenolol (0.1, 1 and 10 mg kg-1) and only statistically significant with the highest dose of ICI 111,581 (5 mg kg-1), and propranolol (10 mg kg-1). 5. Treatment with beta-adrenoceptor blockers elevated serum potassium concentrations, as compared with saline controls, especially when measured at 30 min post-occlusion. 6. Only ICI 111,581 (5 mg kg-1) and propranolol (1 and 10 mg kg-1) prolonged P-R interval. 7. In order to evaluate possible mechanisms of antiarrhythmic action, attempts were made to correlate antiarrhythmic activity with beta-blockade, serum potassium concentrations, and/or with changes in the P-R interval of the ECG. 8. Reductions in arrhythmias did not correlate well with presumed beta-blockade. Better correlation was obtained with elevations of serum potassium concentration, and with prolongation of P-R interval (a presumed Class I antiarrhythmic action). 9. These results suggested that antiarrhythmic effects of adrenoceptor blocking agents in acutely-prepared anaesthetized rats, subjected to occlusion of a coronary artery, are unrelated to cardiac beta-blockade. The limited antiarrhythmic effects which were observed could be attributed to elevations in serum potassium concentration (due to peripheral beta-blockade) and/or possible Class I antiarrhythmic actions.

Adrenergic beta-Antagonists↗
PubMed1989

Antiarrhythmic properties of tetrodotoxin against occlusion-induced arrhythmias in the rat: a novel approach to the study of the antiarrhythmic effects of ventricular sodium channel blockade.

Blockade of ventricular sodium conductance (gNa) is believed to play an important role in the beneficial antiarrhythmic effects of class I antiarrhythmic agents. The present study was undertaken to examine the importance of ventricular gNa blockade by assessing the antiarrhythmic profile of tetrodotoxin (TTX), a selective sodium channel blocker. Experiments were performed in pentobarbital-anesthetized and artificially ventilated rats. Two doses of TTX were tested for antiarrhythmic action: a low dose (low TTX, 10 micrograms/kg of bolus + infusion of 10 micrograms/kg/hr) which blocked only neuronal activity, and a high dose (TTXh, 50 micrograms/kg of bolus + infusion of 50 micrograms/kg/hr) which also produced signs of ventricular gNa blockade in normal hearts. To control for the decreases in blood pressure and heart rate caused by TTX, hexamethonium, nitroprusside and propranolol were also used. Only TTXh possessed antiarrhythmic activity in rats subjected to myocardial ischemia (produced by ligation of the left anterior descending coronary artery). Arrhythmia scores (mean, n = 9) were: saline, 3.8; hexamethonium, 3.8; nitroprusside, 3.2; nitroprusside + propranolol, 4.3; low TTX, 3.9; and TTXh, 0.9. Only TTXh reduced dV/dt max. of the action potential (recorded in vivo by means of 3 M KCl filled microelectrodes) as well as action potential height, and concomitantly prolonged the P-R and QRS intervals of normal hearts. In conclusion, our study demonstrated that drugs which produced hypotension, bradycardia and loss of autonomic function were not antiarrhythmic. On the other hand, the marked antiarrhythmic activity of TTXh appeared to depend upon ventricular gNa blockade. Thus, TTX provides a useful tool for examining the antiarrhythmic properties of ventricular gNa blockade.

Action Potentials↗
PubMed1988

Women's attitudes to withdrawal bleeding and their knowledge and beliefs about the oral contraceptive pill.

One hundred and fifty-eight attenders at general practices and family-planning clinics, and 20 young female doctors volunteered to complete a questionnaire about how women take the oral contraceptive pill, their knowledge of the Pill and their attitudes to withdrawal bleeding. Forty-three per cent of female patients has used the Pill to alter the time of withdrawal bleeding. Twenty-two per cent of female patients had taken the Pill daily for more than six weeks on at least one occasion and all reported positive experiences. However, 83% of female patients believed that it was necessary to bleed monthly when taking the Pill and 69% of the female patients believed that continuous use of active medication is undesirable. The over-all knowledge of the Pill was poor and 43% of female patients did not know what to do if they missed two consecutive Pills. Female doctors were better informed but had similar attitudes about the Pill to those of other women. Forty-six per cent of the female patients and 55% of young female doctors would chose to bleed at intervals of three months or greater if they could determine their own Pill regimen.

Adult↗
PubMed1988

Detecting bacteriuria in a primary maternal and child health care programme.

Urinary tract infection in pregnancy has not been adequately dealt with in developing countries, though its consequences are well recognised. This is primarily because of constraints on resources coupled with a lack of technological infrastructure. An evaluation of the Griess test for the mass screening of urinary tract infection among antenatal women was carried out prospectively using a case-control method. The Griess test was found to be a valid, reliable, and economical screening test for urinary tract infection which can be integrated into a primary maternal and child health care programme.

Bacteriological Techniques↗
PubMed1988

Lipogenic enzyme activities in primary cultures of adult mouse hepatocytes.

The effects of various unsaturated fatty acids such as oleic (18:1n-9), linoleic (18:2n-6) and arachidonic (20:4n-6) on the activities of fatty acid synthetase (FAS), malic enzyme (ME), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) all were determined in primary cultures of mouse hepatocytes. Activities of FAS and ME were found to decrease with time in culture regardless of whether hepatocyte donors were fed diets containing polyunsaturated fatty acid-free hydrogenated cottonseed oil (HCTO) or corn oil (CO). On the other hand, while G6PDH activity also declined in cultured hepatocytes obtained from HCTO-fed mice, the activity of this enzyme increased in cells cultured from CO-fed mice. 6PGDH activity was found to increase in hepatocytes obtained from both diet groups. Neither 18:2 nor 20:4 when added to media could alter FAS or ME activities compared with those observed with either 18:1-containing or fatty acid-free media. Since lactic dehydrogenase activity and the rate of incorporation of [3H] leucine into FAS protein were unaltered with time in hepatocyte cultures, the decreased activities of FAS and ME cannot be attributed to a loss in cell viability during culture but rather appear to be specific for those enzymes which respond to diet hormones in vivo.

Animals↗
PubMed1988

Peritonsillar abscess in an infant.

Although a common enough condition in the general population, quinsy is rare in children and even rarer in infants. In most cases the diagnosis is easy on the basis of the suggestive clinical picture. A case is presented of a peritonsillar abscess in a 7-month-old baby. Here, the diagnosis was somewhat doubtful, due to the uncharacteristic clinical appearance and the young age of the patient. Some of the dangers of an inadequate antibiotic treatment are briefly discussed.

Ampicillin↗
PubMed1988

Activation of multiple hemopoietic growth factor genes in Abelson virus-transformed myeloid cells.

We have recently shown that Abelson murine leukemia (A-MuLV) virus can transform cells in large mixed colonies to give tumorigenic myeloid cell lines capable of autonomous growth in vitro. Initial studies revealed that granulocyte-macrophage colony-stimulating factor (GM-CSF) production was consistently activated in these cells. Using a sensitive S1 RNA mapping technique and additional bioassays, we have now obtained evidence of expression of other hemopoietic growth factor genes. Uniformly 32P-labeled, single-stranded DNA probes (greater than 4 x 10(8) cpm/micrograms) were generated for interleukin 3 (IL-3) and GM-CSF using pTZ based vectors. IL-3 mRNA was detected in four of four cloned transformants (from two different infections) at approximately 1% of the level seen in pokeweed mitogen (PWM)-stimulated spleen cells. GM-CSF mRNA was detected in the two clones that showed the highest IL-3 mRNA levels. Medium conditioned by these cells was able to stimulate IL-3-dependent 32D cells, and IL-3- and GM-CSF-dependent B6SUtA cells, and also supported the growth of a variety of single and multilineage colonies in assays of mouse marrow cells even in the presence of neutralizing antibodies to GM-CSF. Rearrangements of the IL-3 and GM-CSF genes were not apparent by Southern blot analysis. Additional bioassays revealed the presence of two other growth factors: IL-6 (hybridoma growth factor or Ifn-beta 2) assayed on B13.29 cells, a factor-dependent murine B-cell hybridoma; and a new pre-B-cell stimulatory factor different from any of the above. Elucidation of the mechanism underlying this phenomenon may provide important insights into the regulation of hemopoietic growth factor gene expression and the role such genes play in human leukemogenesis.

Abelson murine leukemia virus↗
PubMed1988

Diet-induced asymmetry of the phosphatidylcholine fatty acyl composition in rat erythrocyte membranes.

The effect of dietary fat on the distribution of fatty acids within the bilayer of red cell membrane phosphatidylcholine was determined after feeding young female rats semipurified diets containing 10% of either hydrogenated cottonseed oil, menhaden oil, or corn oil for 4 days. Changes in fatty acyl composition of both plasma and erythrocyte phosphatidylcholine were noted. The composition of the fatty acids in phosphatidylcholine in the outer leaflet of the bilayer was determined after hydrolysis of outer leaflet phospholipids, first with phospholipase A2 and subsequently with sphingomyelinase. The distributions of acyl constituents of phosphatidylcholine in the inner and the outer monolayers of the membrane were found to be distinctively different, regardless of the dietary fat intake. For example, palmitic acid and oleic acid were predominantly present in the phosphatidylcholine of the inner monolayer, and arachidonic acid and docosahexaenoic acid were present in that of the outer monolayer. Despite such diet-induced changes in phosphatidylcholine fatty acid composition, no alteration in erythrocyte integrity was observed when monitored by either morphology or ektacytometry.

Animals↗
PubMed1987

Metabolism of cis-12-octadecenoic acid and trans-9,trans-12-octadecadienoic acid and their influence on lipogenic enzyme activities in mouse liver.

High carbohydrate (65% glucose) diets containing cis-12-octadecenoic acid (12c-18:1) or trans-9,trans-12-octadecadienoic acid (9t,12t-18:2) were fed to weanling mice to investigate the influence of fatty acid structure on six hepatic enzyme activities involved in lipid metabolism. Results with these diets were compared to those with diets containing no fatty acids, saturated fatty acids; cis-9-octadecenoic acid (9c-18:1) and cis-9,cis-12-octadecadienoic acid (9c,12c-18:2). These comparisons show saturated fatty acids, 9c-18:1, 12c-18:1, and 9t,12t-18:2, had little or no influence on the activity levels of fatty acid synthetase, malic enzyme (EC 1.1.1.40)citrate cleavage enzyme (EC 4.1.3.8), glucose-6-phosphate dehydrogenase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 1.1.1.44) and acetyl-CoA carboxylase (EC 6.4.1.2). Neither 12c-18:1 nor 9t,12t-18:2 produced the dramatic enzyme-lowering effect exhibited by the diet containing 9c,12c-18:2 when compared to the diet devoid of fat. Thus, both the 9 and 12 bonds must be present in the same molecule. Also, at least one and probably both bonds must be in the cis configuration to depress liver enzyme activities. Capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were both used for analysis of the methyl esters derived from the hepatic lipids. The GC and GC-MS data provided (a) direct evidence for incorporation of both isomers into hepatic lipids and (b) indirect evidence that 9t,12t-18:2 lowered liver delta 9-desaturase activity. In addition, since these products were found in the complex liver lipids, there is no doubt that the various enzymes concerned with activation and acylation utilize both of these isomeric fatty acids as substrates.

Animals↗