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Biomedical subjects

D Roy

Publications and source records attributed to D Roy.

At least 325 records · Page 18Linked to original sources
PubMed1984

Identification of two of the major phosphorylated polypeptides of the bovine lens utilizing a lens cAMP-dependent protein kinase system.

Two of the major in vitro phosphorylated polypeptides of the bovine lens have been identified. Analysis by means of two-dimensional gel electrophoresis (IEF) has demonstrated that the lens phosphorylated 57,000 and 43,000 dalton polypeptides correspond in mobility to purified phosphorylated bovine lens vimentin and chicken gizzard actin, respectively. Purified actin and vimentin were phosphorylated by a partially purified cAMP-dependent protein kinase isolated from the outer cortex water soluble fraction. All detectable bovine lens vimentin isoelectric variants were phosphorylated. In both the lens fiber cell and chicken gizzard actin preparations, the phosphorylated actin isoelectric variants did not correspond in mobility to the major actin isoelectric variant, but were more acidic. Phosphorylation in all preparations occurred at serine residues.

Actins↗
PubMed1984

Changes in the activity of gamma-amino butyric acid transaminase and succinic semialdehyde dehydrogenase in the cobalt and iron experimental epileptogenic foci in the rat brain.

GABA-transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSA-DH) activities were measured in the mitochondrial fractions from the cobalt- and FeCl3-induced chronic epileptogenic foci in the rat brain. Electroencephalographically, the FeCl3 epileptogenic focus remained active for a duration longer than that of the cobalt focus. In both the foci SSA-DH activity showed significant increases which were concomitant with the EEG epileptiform activity. In cobalt focus, the GABA-T activity fell whereas, in the FeCl3 focus it was unchanged. In cobalt focus fall in GABA-T activity seemed to be concomitant with EEG epileptiform discharge. The measurements of the enzyme activities in the mirror (secondary) foci showed that, except for a brief stimulation of SSA-DH activity in the mirror focus in FeCl3 epileptic animals, the enzyme activities remained unchanged. Possible significance of the observed enzymatic changes in the physiology of epileptogenic focus is discussed.

4-Aminobutyrate Transaminase↗
PubMed1983

Clinical characteristics and long-term follow-up in 119 survivors of cardiac arrest: relation to inducibility at electrophysiologic testing.

Electrophysiologic studies were performed in 119 survivors of cardiac arrest. Sustained ventricular arrhythmias were initiated by programmed ventricular stimulation in 72 patients (61%). Coronary artery disease patients with induced sustained ventricular arrhythmias had a higher incidence of prior myocardial infarction (95 versus 72%) and ventricular aneurysm (59 versus 28%) and a lower ejection fraction (37 versus 50%) than those with no inducible sustained ventricular arrhythmias. Of the 72 patients with inducible ventricular arrhythmias, 11 (15%) died suddenly during a mean follow-up of 18 months (range 15 days to 58 months). In this group, 6 of 41 patients (15%) discharged on a successful antiarrhythmic regimen and 5 of 27 patients (19%) discharged on an unsuccessful regimen or without a predischarge study have died suddenly. Of these 27 patients, 1 of 12 patients treated with amiodarone and 4 of 15 (27%) with conventional antiarrhythmic therapy died suddenly. The remaining 4 patients died of nonarrhythmic causes in the postoperative period. Of 47 patients without inducible sustained ventricular arrhythmias, 15 (32%) died suddenly at a mean follow-up of 20 months, 10 (34%) with and 15 (28%) without empiric therapy. It is concluded that sustained ventricular arrhythmias can be initiated in most patients resuscitated from cardiac arrest. Patients with inducible arrhythmias have greater left ventricular dysfunction than those without inducible arrhythmias. Medical or surgical therapy that prevented the induction of sustained ventricular arrhythmias was predictive of a successful outcome in 85% of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Lens calcium activated proteinase: degradation of vimentin.

The lens has been shown to contain a Ca+2 activated proteinase specific for vimentin. The proteinase is present in the soluble fraction of the cortex but not in the epithelium. It is suggested that this proteinase is expressed during terminal differentiation of the epithelial cells and may be responsible for degradation of the intermediate filaments in the fiber cells. The proteinase is inhibited by EGTA but not by several proteinase inhibitors.

Animals↗
PubMed1983

Polyamines in normal and cataractous human lenses: evidence for post-translational modification.

The polyamine composition of normal and cataractous human lenses has been studied. Polyamines (putrescine, spermidine and spermine) have been shown to occur in the unbound form in the acid-soluble fraction and in the bound form in the acid-insoluble fraction of the lens. It has also been shown that only putrescine occurs in both conjugated and non-conjugated states in the lens, while putrescine as well as spermidine occur in both forms in the aqueous fluid. Estimation of the polyamine content in cataractous lenses indicates elevated levels of both bound and unbound polyamines in these lenses in comparison to the normal lenses. Evidence is presented which indicates an increase in the level of polyamines covalently bound to protein, in a gamma-glutamyl linkage, in the cataractous lens.

Aged↗
PubMed1983

Effect of centrophenoxine on the antioxidative enzymes in various regions of the aging rat brain.

This study investigated the effect (in vivo) of centrophenoxine (Helfergin) on the activity of antioxidant enzymes (glutathione peroxidase GSH-PER, glutathione reductase GSSG-RED, superoxide dismutase SOD and catalase) in subcellular fractions from the regions of the brain (cerebrum, cerebellum and brain stem) of rats aged 6, 9 and 12 months. In all age groups, normal (control) activity of GSH-PER, GSSG-RED and SOD in the three brain regions was higher in the soluble fractions than in the particulate fractions. The three regions of the brain showed different levels of the enzyme activities. Enzymes in soluble fractions (except GSSG-RED in cerebrum of rats aged 12 months) did not change with age. In particulate fractions, however, the enzymes showed age-related changes: GSH-PER decreased with age in cerebellum and brain stem, but showed an age-related increase in cerebrum, GSSG-RED and SOD increased with age in all the three brain regions. Catalase activity in all the three brain regions remained unchanged in all age groups. Six week administration of centrophenoxine (once a day in doses of 80 mg/Kg and 120 mg/Kg) to the experimental animals produced increases in the activity of SOD, GSH-PER and GSSG-RED in particulate fractions from all the three brain regions. In the soluble fractions, however, only SOD and GSH-PER activity was increased. In vitro also centrophenoxine stimulated the activity of GSH-PER. A dosage of 80 mg/Kg produced greater changes than a 120 mg/Kg dosage. The drug had no effect on the activity of catalase. Centrophenoxine also reduced lipofuscin deposits (studied both biochemically and histochemically) thus indicating that the drug inhibited lipofuscin accumulation by elevating the activity of the antioxidant enzymes. The data suggest that alleviation of senescence by centrophenoxine may, at least, partly be due to activation by it of antioxidant enzymes.

Aging↗
PubMed1983

Subendocardial resection for refractory ventricular tachycardia: effects on ambulatory electrocardiogram, programmed stimulation and ejection fraction, and relation to outcome.

The inducibility of ventricular tachycardia by programmed stimulation was correlated with ventricular ectopic activity on ambulatory electrocardiogram, ejection fraction and clinical outcome in 36 patients after endocardial resection for medically refractory ventricular tachycardia. Ventricular tachycardia was noninducible postoperatively in 25 patients and was inducible in 11. After administration of antiarrhythmic drugs, ventricular tachycardia could no longer be induced in four patients and remained inducible in the other seven patients. All 36 patients had postoperative and 20 had preoperative ambulatory electrocardiograms obtained while they were not receiving drug therapy. Pre- and postoperative ambulatory electrocardiograms did not differ in mean hourly ventricular premature depolarization frequency, Lown arrhythmia grade or change in grade (pre- vs. postoperative). The majority of postoperative patients had repetitive forms of ventricular arrhythmia postoperatively and there was no difference between patients with inducible and noninducible ventricular tachycardia in regard to Holter monitoring characteristics. There was no significant difference in postoperative ejection fraction between patients with inducible and noninducible ventricular tachycardia postoperatively. Ventricular tachycardia has recurred in 2 of 29 patients who had no inducible tachycardia at the time of hospital discharge and were followed up for a mean of 1 year; it has recurred in one of seven patients in whom it was still inducible at the time of hospital discharge and who were followed up for a mean of 7 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Effects of a high-complex-carbohydrate, low-fat diet and daily exercise on individuals 70 years of age and older.

Data were obtained from 70 individuals (M age = 78.7, SE = 4.1 years) who attended the Pritikin Longevity Center's 26-day residential program where they were exposed to a high-complex-carbohydrate, low-fat diet, and daily exercise. During the 26-day program, serum cholesterol was reduced from 222 (SE = 5) to 179 (SE = 5) mg/dl, and triglycerides were reduced from 156 (SE = 10) to 141 (SE = 7) mg/dl. Body weight was reduced an average of 2.2 kg. Treadmill performance increased from 3.7 (SE = .1) to 5.5 (SE = .2) METs. During the final week of the program, average daily walking was 5.1 (SE = .3) km. Forty-six hypertensive patients reduced their pressure from 154/80 to 150/77 mmHg, with 9 of 18 patients discontinuing their antihypertensive medication. Thirteen type II diabetic patients reduced their fasting serum glucose from 164 (SE = 4) to 120 (SE = 2) mg/dl.

Aged↗
PubMed1983

Repetitive responses to ventricular extrastimuli: incidence and significance in patients without organic heart disease.

Of 110 patients without organic heart disease undergoing electrophysiological evaluation, 72 patients (65%) manifested some form of repetitive ventricular response to ventricular stimulation. In 58 (53%) bundle branch re-entry was induced and in 19 patients (17%) intraventricular re-entry. In five patients (4%) both types of repetitive responses were initiated. The indication for study was documented as ventricular tachycardia or fibrillation in 13% of the patients, supraventricular tachycardia in 51% and Wolff-Parkinson-White syndrome, syncope or conduction disturbances in the remaining patients. The incidence of clinical and inducible ventricular tachycardia or fibrillation was 8 and 2% respectively, in the group of patients manifesting only bundle branch re-entry, 37 and 32% in patients with intraventricular re-entry and 8 and 11% in patients without repetitive ventricular responses during ventricular stimulation. The predictive value of intraventricular re-entry as an indicator of severe ventricular arrhythmias was 36%. We conclude that in our population of patients without organic heart disease, bundle branch re-entry is a frequent finding and is not related to ventricular arrhythmias, that intraventricular re-entry is less frequent and although it is associated with a higher incidence of ventricular tachycardia or fibrillation, it is a poor predictor of these arrhythmias in this study population.

Adult↗
PubMed1983

The prevention of recurrent suicidal acts.

1 There have been few controlled prospective investigations into the prevention of suicidal behaviour and by and large they have failed to demonstrate the efficacy of social work, psychotherapy or psychiatric treatment. 2 A group of 58 high-risk patients with multiple episodes of suicidal behaviour was treated with mianserin 30 mg at night or placebo in a six month double-blind trial of the efficacy of an antidepressant in reducing suicidal behaviour. 3 Patients were screened for depression, schizophrenia and organic disease. Patients were diagnosed as suffering from personality disorders according to DSM-III criteria mainly borderline or histrionic. 4 There was no significant difference in outcome between the mianserin and placebo treated group at any point in the six month study. 5 An item analysis of the MADRS showed that at entry the item 'reduced appetite' predicted subsequent suicidal attempt. The total MADRS score did not predict further suicidal acts at entry but was highly significant at four weeks. At four weeks the items 'reduced sleep' and 'reduced appetite' were highly significant predictors of further suicidal acts and the items 'lassitude', 'suicidal thoughts', 'inability to feel' and 'pessimistic thoughts' were significant predictors.

Adult↗
PubMed1983

Plasma levels and clinical response with imipramine in a study comparing efficacy with mianserin and nomifensine.

1 The comparative antidepressant efficacy of 150 mg imipramine, 60 mg mianserin and 150 mg nomifensine was studied in 45 depressed patients in a six week double-blind investigation. 2 In the efficacy analysis of 41 patients completing the study there was no overall significant difference in efficacy between the groups. Individual group comparisons showed no significant difference in response between mianserin and nomifensine, and mianserin and imipramine. There was a significant (z = 1.99, P less than 0.05) improved response in the imipramine compared with the nomifensine treated group. The imipramine treated group were significantly older. 3 No significant plasma concentration/clinical response relationships were demonstrated with nomifensine, mianserin, imipramine or desipramine. 4 Plasma level monitoring of imipramine recommended by some investigators does not seem to be appropriate.

Adult↗
PubMed1983

Localization of the accessory pathway in the Wolff-Parkinson-White syndrome from the ventriculo-atrial conduction time of right ventricular apical extrasystoles.

In 18 consecutive patients with the Wolff-Parkinson-White syndrome undergoing electrophysiologic study, the ventriculo-atrial conduction time of right ventricular apical extrasystoles which advanced atrial activation during circus movement tachycardia was studied in relation to accessory pathway location. Accessory pathway location was determined by delta wave morphology during maximal pre-excitation, mapping of atrial activation during circus movement tachycardia and ventricular pacing, the effect of bundle branch block on ventriculo-atrial conduction time during circus movement tachycardia, and the effect of pacing from different sites in the atria on the stimulus-to-delta wave interval. In 7 patients with septal accessory pathways, ventriculo-atrial conduction time was similar during circus movement tachycardia and following right ventricular apical extrasystoles (mean difference 0 +/- 6 ms, range -5 to +10 ms). In contrast, in 11 patients with a left free wall accessory pathway, ventriculo-atrial conduction time increased by 46 +/- 15 ms (range 15 to 65 ms) following right ventricular apical extrasystoles. Therefore, measurement of the ventriculo-atrial conduction time of right ventricular extrasystoles during circus movement tachycardia provides an easy way to distinguish between septal and left free wall accessory pathways. This finding may be of particular use in determining the location of concealed bypass tracts.

Adolescent↗
PubMed1983

Horizontal and longitudinal dissociation of the A-V node during atrial tachycardia.

The co-existence of horizontal and longitudinal dissociation of the atrioventricular (A-V) node has not previously been reported. Analysis of ECG tracings from 4 patients with supraventricular tachycardias showing an irregular ventricular rate suggest that such a mechanism was responsible for the irregular A-V conduction pattern. His bundle recording was obtained in one patient and revealed the site of block to be located in the A-V node. Multi-level block and longitudinal dissociation of the A-V node is probably not rare and should be included in the discussion of supraventricular arrhythmias displaying irregular ventricular rates.

Adult↗
PubMed1983

Atrial tachycardia facilitating initiation of ventricular tachycardia.

A 17-year-old male was studied because of clinically documented tachycardias showing narrow and wide QRS complexes. He was found to suffer from an atrial and a ventricular tachycardia. It was demonstrated that initiation of ventricular tachycardia occurred on reaching a critical ventricular rate during atrial tachycardia. Our study illustrates the value of electrophysiological studies in patients suspected of suffering from double or multiple tachycardias. It also shows that the occurrence of one type of tachycardia may be critically related to another type of tachycardia.

Adolescent↗
PubMed1983

Age-related changes in glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in the subcellular fractions from the rat brain and the effect of dimethylaminoethanol.

The activity of pentose phosphate pathway enzymes (glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase) was measured in the cytosol and the particulate fractions (mitochondrial-synaptosomal and microsomal) from the cerebrum and the cerebellum of the rats aged 1, 2, 3, 6, 9 and 12 months. The results showed that the two enzymes occurred both in cytosol and particulate fractions. Both the enzymes were higher in the particulate fractions from cerebellum than in the same fractions from cerebrum. In both regions of the brain, particulate fraction enzymes showed an age-related decline in their activity, but the cytosol fraction enzymes remained unchanged in all the age groups. Dimethylaminoethanol, an important molecular constituent of some antiageing drugs, increased the activity of these enzymes in a dose dependent manner only in the particulate fractions.

Aging↗