Biomedical subjects

N Chetty

Publications and source records attributed to N Chetty.

44 records · Page 3Linked to original sources

PubMed1985

Long-term ultra-low-dose aspirin therapy and platelet function.

The effect of ultra-low-dose aspirin on platelet aggregation and thromboxane B2 (TXB2) production was studied in two groups of normal subjects. Group 1 received 162 mg/d and group 2 received 20 mg/d for 4 weeks. For the first 2 weeks the effects were similar in the two groups, namely inhibition of aggregation and inhibition of TXB2 production. However, after 4 weeks there was significantly less inhibition of platelet aggregation in those receiving 20 mg/d. Inhibition of TXB2 production in the two groups was not significantly different. Two of 9 individuals receiving 20 mg/d showed an escape from the aspirin effect by the 4th week. When 40 mg/d was given to these 2 individuals they again responded. A daily dose of 20 mg aspirin is therefore too small to maintain adequate inhibition of platelet function in normal subjects.

Adenosine Diphosphate↗

PubMed1983

The effect of low-dose aspirin and platelet aggregation in familial hypercholesterolaemia.

Since the platelets of patients with familial hypercholesterolaemia (FH) are hyperaggregable, the inhibitory effect of low-dose aspirin on platelet aggregation in response to adenosine diphosphate, collagen, adrenaline and arachidonic acid was tested in 9 young adult patients with FH and compared with that in 9 normal subjects. After a single oral dose (150 mg) of aspirin the degree of inhibition of platelet aggregation was the same in the two groups, as was the recovery time (in days) for full restoration of platelet aggregation . In a second experiment in which 162 mg aspirin was administered daily for 28 days, inhibition of platelet aggregation was sustainable in both the patient and the control groups. These results suggest that despite the recognized hyperaggregability of platelets from patients with FH, daily low-dose aspirin ingestion effectively inhibits their in vitro aggregation and may therefore prove beneficial as supplemental therapy to reduce the rate of myocardial infarction in this high-risk group.

Adult↗

PubMed1983

The effects of a vegetarian diet on platelet function and fatty acids.

Nine healthy subjects taking an average mixed "Western" diet were placed on a vegetarian diet poor in arachidonic acid for four weeks. All animal and marine foods except for cows milk and milk products were excluded. Platelet aggregation responses to arachidonic acid and epinephrine increased slightly whereas responses to ADP and collagen were unchanged. Platelet thromboxane production, platelet counts, serum LDL cholesterol and triglycerides did not change but total and HDL serum cholesterol levels fell significantly. There was a significant rise in platelet arachidonic acid content but other platelet fatty acids did not change significantly. A reduction in dietary arachidonic acid did not inhibit platelet aggregation or thromboxane production.

Adult↗

PubMed1983

The effects of a mixed fish diet on platelet function, fatty acids and serum lipids.

Eight healthy subjects were fed a diet containing 1-4 g eicosapentaenoic acid (EPA) daily for 8-21 days. The EPA was derived from 300-400 g per day of sardines, pilchards, herring and/or kabeljou. Sources of arachidonic acid (AA) in the diet were reduced. At the end of the experimental period there was an increase in the ratio of EPA to AA in the platelets and a decrease in platelet aggregation to ADP, epinephrine and collagen. Aggregation to AA was not reduced. Thromboxane production in response to all four agonists was reduced. Serum total and HDL cholesterol levels fell significantly but platelet counts, LDL cholesterol and triglyceride values did not change. We conclude that even a relatively modest intake of EPA derived from a mixed fish diet together with a reduction in AA intake can alter in vitro platelet function and serum lipids significantly. A long term controlled trial of a palatable mixed fish diet to assess possible antithrombotic and antiatherogenic effects is justifiable.

Adenosine Diphosphate↗

PubMed1982

Dosage frequency for suppression of platelet function by low dose aspirin therapy.

A study of platelet aggregation and MDA production after an oral dose of 300 mg aspirin indicated that partial recovery of platelet function occurred when approximately one third of the circulating platelets had been replaced by new (uninhibited) platelets. In vitro studies on mixtures of normal and aspirin inhibited platelets indicated partial restoration of platelet aggregation and thromboxane B2 production with as little as 10% of normal platelets in some subjects. Restoration of full function required a higher proportion of normal platelets. There was considerable variation between subjects. These data suggest that complete suppression of platelet functions in all normal subjects requires daily administration of the drug.

Adenosine Diphosphate↗

PubMed1982

Platelet function in familial hypercholesterolaemia in South Africa and the effects of probucol.

Patients with Familial Hyperlipoproteinaemia Type II showed evidence of increased platelet aggregability when compared to normal controls. This abnormality was not influenced by oral therapy with probucol whether or not the serum cholesterol levels were lowered during the study period. Probucol assays indicated adequate compliance during the study period but did not demonstrate any uptake of the drug by platelets. In vitro studies also failed to demonstrate any inhibition of platelet function at therapeutic drug levels although higher levels were inhibitory.

Adolescent↗

PubMedDate not supplied

Metallic stents in malignant biliary obstruction: results of a multicenter European study of 240 patients.

PURPOSE: In this retrospective multicenter study, the authors analyzed the clinical efficacy of different metallic stents in the palliative treatment of patients with neoplastic obstructive jaundice. PATIENTS AND METHODS: Two hundred forty patients were treated in four European centers. Causes of obstruction were pancreatic carcinoma (n = 84), biliary neoplasm (n = 99), metastases in hilar nodes (n = 34), primary or secondary liver tumors (n = 4), and other tumors (n = 19). A total of 388 metallic stents were used: 300 Wallstents, 35 nitinol Strecker stents, 40 Gianturco-Rosch Z stents, and 13 tantalum Strecker stents. RESULTS: Overall 25- and 50-week survival rates were 42% and 16%, respectively; the 30-day mortality rate was 14.6%. Two deaths were related to the procedure (0.8%); 19 patients (8%) had major complications. The 25-week patency rate was significantly higher for the nitinol Strecker stents and the Wallstents (78% and 67%, respectively) than for the Z stents and the tantalum Strecker stents (30% and 20%, respectively) (P < .01 and P < .001, respectively). Average patency was 8.3, 5.9, 2.3, and 4.0 months, respectively. Reintervention due to stent obstruction was necessary in 53 patients. CONCLUSION: The Wallstent and the nitinol Strecker stents were the most effective in achieving long-term palliation. Patency was significantly affected by the level of obstruction but not by the type of obstructing tumor.

Aged↗

PubMedDate not supplied

Hyperbaric oxygen therapy for delayed radiation injuries in gynecological cancers.

Delayed radiation-induced injuries are difficult to treat. The treatment of delayed radiation injuries with hyperbaric oxygen therapy (HBOT) is reported in small case series and case reports. This study reports the experience of a single institution with HBOT in delayed radiation injuries in patients with gynecological cancers. At least 20 sessions of 100% oxygen inhalation at 2.4 Atmospheric Absolutes (ATA) for 90 min in a hyperbaric chamber were carried out. Of the 14 patients included in the study, 10 patients have healed or showed improvement of more than 50%, resulting in a success rate of 71%. Mean follow-up was 31.6 months (range 6-70 months). The adverse events were acceptable. HBOT should be considered for patients with delayed radiation injuries, not responding to other treatments.

Adult↗