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Biomedical subjects

R Ponnudurai

Publications and source records attributed to R Ponnudurai.

At least 19 recordsLinked to original sources
PubMed2001

Prednisone withdrawal followed by interferon alpha for treatment of chronic hepatitis C infection: results of a randomized controlled trial.

Immunosuppressive therapy increases levels of hepatitis C virus (HCV) RNA, and when combined with interferon, corticosteroids have been reported to variably improve or have no effect on sustained response rates. We conducted a randomized double-blind placebo-controlled trial in 39 patients with biopsy-proven chronic HCV infection and elevated alanine aminotransferase levels. Patients received either 6 weeks of a tapering dose of prednisone (60 ng, 40 mg, and 20 mg in 2-week intervals) or an identical placebo. All patients then received recombinant interferon alpha-2b, 3 million units three times a week for 24 weeks. Patients were then followed for a further 24 weeks. At the end of the study there was no significant difference in the sustained biochemical response rates between the two groups (4/20 vs. 3/19, p value was not significant). Prednisone-treated patients had a significant increase in HCV RNA from baseline during steroid treatment (400 +/- 60% increase vs. -280 +/- 140% decrease; p = 0.005). Two prednisone-treated patients were withdrawn from the study secondary to serious complications related to therapy. Prednisone priming before interferon alpha therapy in patients with chronic HCV infection does not improve the sustained response rate. This therapy was associated with an increase in viral burden and significant morbidity.

Adult↗
PubMed2001

Ondansetron: a selective 5-HT(3) receptor antagonist and its applications in CNS-related disorders.

Ondansetron is a selective 5-hydroxytryptamine(3) (5-HT(3)) receptor antagonist that has been introduced to clinical practice as an antiemetic for cancer treatment-induced and anesthesia-related nausea and vomiting. Its use under these circumstances is both prophylactic and therapeutic. It has a superior efficacy, safety and pharmacoeconomic profile compared with other groups of antiemetics, namely antidopaminergics, antihistamines and anticholinergics. However, its place in the management of anticipatory and delayed vomiting in cancer treatment and as a rescue antiemetic in surgical patients needs to be further explored. Furthermore, recent animal and human research also reflects its possible novel application in the treatment of other disease states, such as alcoholism, cocaine addiction, opioid withdrawal syndrome, anxiety disorders, gastrointestinal motility disorders, Tourette's syndrome and pruritus. This review revisits the widespread physiological and pathological effects of 5-HT and discusses both the basic science literature and the clinical developments responsible for the conventional and novel uses of ondansetron. In addition, new discoveries relating to the effects of ondansetron on other receptors/channels and their possible therapeutic applications are presented.

Animals↗
PubMed1999

Relevance of sequential development of dermatoglyphics to schizophrenia.

Since the embryogeneses of epidermal ridges of hands and feet are reported to be identical, although those of the feet develop two or three weeks later, a tendency for symmetry or correspondence between each side finger and toe pairs could be envisaged. Any prenatal insult could disturb such developmental mechanisms, causing the lowering of either finger or toe ridge counts which might result in augmentation of differences between them. To test this hypothesis, the differences between each side thumb and big toe ridge counts of 89 schizophrenic patients and 65 control subjects were assessed. These samples were also subgrouped into those with and without identical pattern distributions on each side of their thumb and big toe pairs. Female schizophrenics who displayed identical patterns manifested significantly greater differences between their right thumb and big toe ridge counts in comparison to the control subjects (P = 0.0142). To elucidate the contributory digit for such a greater difference, the ridge counts of the right thumbs and big toes of the female patients were compared with the corresponding counts of the control subjects. The mean ridge count of the big toes was lesser in the patient group compared with that in the control subjects, a difference, however, that did not attain statistical significance.

Adult↗
PubMed1999

Ultracentrifugation and concentration of a large volume of serum for HCV RNA during treatment may predict sustained and relapse response in chronic HCV infection.

The ability to predict accurately a sustained response during therapy in patients with hepatitis C virus (HCV) infection is unavailable. The aim of this study was to differentiate, during therapy, patients who would relapse from those with a sustained response by ultracentrifugation for residual serum HCV RNA. Sixty-one specimens (from 32 patients) collected during interferon therapy were assessed by ultracentrifugation. All were negative using a quantitative polymerase chain reaction (PCR) (detection limit < or = 100 copies/ml). One-milliliter aliquots were ultracentrifuged at 23,000 x g (160 min), and then the nucleic acid pellet was extracted, precipitated, and resuspended. Qualitative PCR was carried out in quadruplicate using two separate 5'UTR primer sets (8 results/specimen). A specimen was positive if > or = 1 gels was positive compared to controls. At weeks 12 and 24, 9/9 (100%) sustained response patients were negative by ultracentrifugation. In the 23 relapse patients at week 12, 7/12 specimens were positive; at week 24, 7/14 were positive. Earlier time points could not differentiate the patients' eventual response to therapy. The predictive value of a positive ultracentrifugation test for relapse at week 12 or 24 was 100%. The predictive value of a negative test for sustained response was 62% and 50% at week 12 and 24, respectively. These preliminary results indicate that patients with an eventual sustained response will have no detectable serum HCV RNA by week 12 or week 24. A positive result is 100% predictive of relapse.

Adult↗
PubMed1996

Failure to support a pseudoautosomal locus for schizophrenia.

Evidence for a pseudoautosomal locus for schizophrenia was sought through an assessment of the psychiatric status of the uncles and aunts (n = 30) of schizophrenic patients. The proportion of affected paternal uncles did not differ from that of affected paternal aunts. Likewise, the proportion of affected maternal aunts did not differ from that of affected maternal uncles. The research design used in this study failed to support the pseudoautosomal hypothesis of schizophrenia.

Adult↗
PubMed1996

Deceptive prothrombin and activated partial thromboplastin times in alcoholic cirrhosis.

It is believed that perioperative hemorrhage, in the hepatoportal area, results from a coagulopathy. This study determined if this could be quantitated by a modified recalcification time (MRT) test developed in our laboratory. Unlike prothrombin (PT) and activated partial thromboplastin times (APTT), the MRT is performed with whole blood to ensure the role of blood cells and chemicals (particularly tissue factor, a potent procoagulant) in the coagulation process. Candidates for liver transplantation (n = 11) were studied. Samples (5 mL) of citrated venous blood were obtained from the patients. Aliquots (1 mL) from these samples were divided into groups of vials labeled C, S, and E. Groups C and S received 20 microL saline and group E, 20 microL of saline containing 10 micrograms of Escherichia coli endotoxin (055: B5W). Vial C was incubated for 10 minutes and vials S and E for 120 minutes, all at 37 degrees C. Then, the MRT was determined on 300 microL of blood from each vial after adding 40 microL of 0.1M calcium chloride. Mean MRT values (minutes +/- standard deviation) for C (MRTC), for S (MRTS), and for E (MRTE) were compared with like values from healthy controls (n = 29). Despite prolonged PT and APTT values, MRT values were shortened in patients with cirrhosis. This hypercoagulability detected by the MRT exonerates a hemorrhagic coagulopathy and possibly implicates widened and thinned gaps in the walls of the portal venous tributaries as the cause of perioperative hemorrhage.

Blood Coagulation Disorders↗
PubMed1995

Tumor necrosis factor-induced necrosis: a monocyte-mediated hypercoagulable effect.

The mechanisms by which tumor necrosis factor (TNF) exerts its necrotic effects are somewhat obscure. We hypothesize that TNF, by monocyte activation, produces the procoagulant tissue factor, thus leading to a state of hypercoagulability with resultant thrombotic vascular occlusion and tissue necrosis. To test this hypothesis, modified recalcification time values (in minutes +/- standard deviation) were obtained on aliquots of blood with A) 20 microL of albumin, B) 20 microL of saline containing endotoxin, and C) 20 microL of albumin with 450 units of TNF. No differences were noted if the samples were not incubated. We conclude that TNF, can cause tumor (tissue) necrosis, and since incubation is required, TNF alone (without monocyte activation) has no procoagulant activity.

Blood Coagulation↗
PubMed1995

Are hypertensives hypercoagulable?

Angiotensin II is a prothrombotic vasoconstrictor. This study proves that many hypertensives are hypercoagulable and at risk for myocardial infarction. The modified recalcification time (MRT) test, used to assess hypercoagulability, incorporates the role of tissue factor in coagulation by activating the monocyte with endotoxin to release latent tissue factor. Aliquots of citrated blood obtained from hypertensives and normotensive controls were placed in two groups of vials, one with saline (group S) and one with endotoxin (group E). All vials were incubated at 37 degrees C for 2 hours, citrate neutralized with calcium chloride, and the MRT (in minutes) for group S (MRT S) and for group E (MRT E) was determined. Mean MRT S values +/- standard deviation (SD) for hypertensives (n = 25) and for controls (n = 27) were 6.4 +/- 1.2 and 6.8 +/- 1.2, respectively. The MRT E values were 4.3 +/- 1.2 and 5.7 +/- 0.9 for the hypertensives and controls, respectively. The MRT E, not the MRT S, was significant. Hypertensives had MRT E values < 4.5 minutes, and by our established criteria, were hypercoagulable. We conclude that because hypercoagulability is a risk factor for thrombosis, hypertensives with short MRT E values may be at increased risk for myocardial or other thrombotic events.

Blood Coagulation Tests↗