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Biomedical subjects

A Goel

Publications and source records attributed to A Goel.

At least 289 records · Page 16Linked to original sources
PubMed1989

Review of a liver transplantation programme.

Liver transplantation is now a routine operation in specialist centres. The author reviews the programme of a pioneering unit in Pittsburgh, USA, which he observed during an elective.

Graft Rejection↗
PubMed1989

Cerebellopontine angle epidermoid cysts: a report on 30 cases.

Thirty cases of cerebellopontine angle epidermoid cysts treated over a period of 20 years are reviewed with regard to their clinical features, the pathophysiology of their symptoms and their management. The predominating symptoms were related to the 7th and 8th cranial nerves and headaches. The signs and symptoms were present for an average period of 4 months. It was not always possible to determine if the signs and symptoms were due to local involvement by the epidermoid, increased intracranial pressure, or both. Diagnostic procedures evolved from angiography and ventriculography to non-invasive computed tomography and MRI. The posterior cranial fossa approach was used in 27 cases. Total excision of the epidermoid was the aim and was carried out in five (18%) patients but concern regarding the preservation of nearby important neurovascular structures forced partial removal in 22 patients. To minimise reformation, the residual epidermoid was carefully coagulated with the aid of the operating microscope and bipolar cautery without damaging surrounding neurovascular structures.

Adolescent↗
PubMed1988

Bacteriocin (klebocin) typing of clinical isolates of Klebsiella pneumoniae.

Three-hundred-forty-two clinical isolates of Klebsiella pneumoniae were subjected to bacteriocin (klebocin) typing using six standard klebocin-producer strains (153-158). The overall typability was 72.8 per cent. The predominant klebocin types found were 244 (14.3 per cent), 313 (13.7 per cent) and 113 (7.6 per cent). Klebocin types 314 and 111 each contributed 5.2 per cent to the total number of isolates. No significant correlation was observed between the source of isolation and the klebocin type.

Antibiosis↗
PubMed1988

Transposable element-mediated enhancement of gene expression in Saccharomyces cerevisiae involves sequence-specific binding of a trans-acting factor.

In our studies on the regulation of adjacent-gene expression by Ty sequences, we demonstrated that a single-base-pair change (T-A----C-G) in the epsilon sequence of Ty917-derived elements is primarily responsible for enhancement of beta-galactosidase expression from lacZ fusion plasmids. Using an electrophoretic gel mobility assay, we showed that the same base pair transition is required for binding of a trans-acting factor, TyBF, from crude cell extracts in vitro. We identified the site of TyBF binding and determined the guanine nucleotide contact sites required for TyBF interaction. We propose that TyBF binding to cis-acting Ty2 sequences activates adjacent-gene transcription.

Base Sequence↗
PubMed1985

Variation in the relationship between serum and saliva lithium levels.

This study has been carried out to find out the reasons for the wide variations observed in the correlation between serum and saliva lithium levels. Serum/saliva lithium levels were monitored in 10 individuals on 6 occasions. The correlation coefficient (r) varied within individuals from 0.19 to 0.91 (p less than 0.025) whereas when all the individuals were considered simultaneously, it was 0.59 (p less than 0.005). It was concluded that prediction of serum lithium levels from salivary lithium levels would only be possible in those individuals showing good correlation. The variability in this correlation could be mainly due to inter-individual variations in the particular sample of individuals studied.

Humans↗
PubMed1983

Saliva lithium levels for monitoring lithium prophylaxis of manic depressive psychosis.

The usefulness of salivary lithium values for monitoring long-term lithium prophylaxis was studied in 60 patients on lithium therapy. A total of 99 pairs of saliva and serum samples were obtained, and the correlation between serum and salivary lithium levels (r = 0.73) was found to be significant at the 1% level. The ratio of salivary serum levels to that of serum was found to range from 1.77 to 6.68. The ratio of 51% of the samples was between 3 and 3.99. It is therefore suggested that it is important to identify the subgroup of patients who show better correlation of salivary and serum lithium levels and use each individual's ratio to monitor only his lithium therapy.

Bipolar Disorder↗
PubMedDate not supplied

Evaluation of zinc in the regulation of serum T3 and T4 levels and hepatic functions in carbontetrachloride-intoxicated rats.

Circulating tri-iodothyronine (T3) and thyroxine (T4) concentrations were determined after 6 wk of zinc treatment to carbontetrachloride (CCl4) intoxicated male albino rats. Concentrations of T3 were observed to be significantly depressed following CCl4 treatment alone. On the contrary, no significant change was noticed in the concentrations of T4 when compared to controls. However, zinc administration to hepatotoxic animals resulted in restoring the T3 activity to within normal limits, thus indicating the indirect effects of zinc on the regulation of thyroid hormone concentrations. The activities of all the serum and hepatic marker enzymes were found to be significantly elevated following CCl4 treatment. However, following zinc supplementation to these intoxicated animals, the levels of the marker enzymes decreased significantly when compared to the CCl4-treated animals. A similar trend was seen in the case of lipid peroxidation following zinc treatment.

Alanine Transaminase↗
PubMedDate not supplied

Suppressed acid formation by cofeeding of glucose and citrate in Bacillus cultures: emergence of pyruvate kinase as a potential metabolic engineering site.

Microbial cultures typically produce acids when metabolizing the common carbon source, glucose. Acid production not only represents a waste of carbon, but its accumulation can limit cell concentration and culture stability, thereby reducing productivity. On the basis of prior work, acid production was attributed to be due to a mismatch between glycolytic and tricarboxylic acid (TCA) cycle capacities. To suppress acid production, a strategy entailing adding citrate to glucose minimal medium proved extremely effective. The effect of citrate on in-vivo flux distribution was quantified using a detailed flux-model. When the molar glucose-citrate ratio was varied between 3 and 6, a significant reduction in glycolytic flux and essentially complete suppression of acid formation was found as compared to chemostat cultures grown solely on glucose. Adding other biosynthetic precursors such as glutamine did not invoke the same suppression, thus indicating that citrate's effect is at the regulatory level. We hypothesized that the reduction of glycolytic flux in the presence of citrate results from its transport being coupled with the uptake of divalent metal ions. Citrate transport alters the intracellular balance of metal ions which in turn could trigger a sophisticated series of metabolic events leading to reduction of the activities of the pyruvate kinase and phosphofructokinase (PFK), the regulatory enzymes of glycolysis. On the basis of this scenario and other regulatory information, pyruvate kinase has emerged as a potential metabolic engineering site. It's deactivation in Bacillus subtilis or Escherichia coli strains is expected to yield constructs with a much lower tendency for making acid byproducts.

Bacillus↗
PubMedDate not supplied

Structure-activity study on antiulcer agents using Wiener's topological index and molecular connectivity index.

The relationship of Wiener's topological index and molecular connectivity index with antiulcer activity of a series of 4-substituted-2-guanidino thiazole analogs has been investigated. The values of Wiener's topological index and molecular connectivity index of 128 compounds were computed and active ranges were identified. The activity assigned to each analog using these topological descriptors was subsequently compared with the reported in vitro and in vivo activities against gastric hydrogen-potassium stimulated adenosine triphosphatase (H+K(+)-ATPase) enzyme. Predictions with an accuracy of the order of approximately 89% were observed with regard to in vivo activity using these topological indices.

Animals↗