Biomedical subjects

G J Sexton

Publications and source records attributed to G J Sexton.

5 recordsLinked to original sources

PubMed1992

Comparative hypolipidemic effects of lovastatin and simvastatin in patients with heterozygous familial hypercholesterolemia.

We have compared the effects of lovastatin and simvastatin on plasma lipoproteins, fibrinogen and urinary mevalonic acid excretion in twenty-three patients with heterozygous familial hypercholesterolemia. After a baseline period patients were randomly assigned to receive lovastatin or simvastatin at doses of 10, 20 and 40 mg twice daily, for a period of 2 months each, and then, after a 4-week wash-out period, all patients received the alternate drug for a similar period of therapy. Both drugs were well-tolerated and no patients were withdrawn due to side effects. Lipid values returned to baseline after discontinuation of therapy and no carry-over effect was observed. Treatment with lovastatin resulted in decreases in LDL cholesterol concentrations from 274 mg/dl at baseline to 211, 192 and 178 mg/dl, respectively, on doses of 20, 40 and 80 mg/day. Treatment with simvastatin reduced concentrations of LDL cholesterol to 194, 168 and 156 mg/dl, respectively, on doses of 20, 40 and 80 mg/day. Concentrations of HDL cholesterol increased on both drugs, but no dose response relationship was apparent. Both drugs reduced the 24-h urinary excretion of mevalonic acid, an intermediate in cholesterol biosynthesis, but the magnitude of decrease was similar with lovastatin and simvastatin. Small, but statistically non-significant decreases in fibrinogen occurred with both drugs. Patients who showed the greatest hypolipidemic effect during treatment with lovastatin also showed an excellent therapeutic response to simvastatin and vice versa. We conclude that, on a milligram per milligram basis, simvastatin is twice as potent as lovastatin in the treatment of familial hypercholesterolemia and that with both drugs, reductions in LDL cholesterol concentrations are accompanied by decreases in the urinary excretion of mevalonic acid.

Adult↗

PubMed1992

Automation of conformational analysis and other molecular modeling calculations.

A software system has been developed for facilitating modeling calculations on large numbers of molecules. Using the system, it is possible to subject one or more molecules to a series of calculations, each requiring use of a different computer program. No user intervention is required: where necessary, output from one program is used automatically as input to the next. Names are assigned to output files automatically and in a systematic manner. As an example, the system can be used to perform a succession of calculations aimed at identifying the major low-energy conformers of each of a set of molecules, starting only from their chemical connectivities. The reliability of the results has been tested by calculations on 40 molecules taken from the Cambridge Structural Database. The observed crystal structure geometry could be found for the majority of these molecules.

Computer Simulation↗

PubMed1979

Pulmonary function in heterozygotes for alpha,-antitrypsin deficiency: a case-control study.

In this paper we present the initial cross-sectional data from a prospective study of lung aging in heterozygotes for alpha 1-antitrypsin deficiency. Using a case-control design, our cases included 37 heterozygotes for alpha 1-antitrypsin deficiency, protease inhibitor phenotypes MZ and MS, selected because they were parents of children with homozygous alpha 1-antitrypsin deficiency identified in a statewide newborn screening program between 1971 and 1974. All of the heterozygotes were less than 40 yr of age. Our control subjects were selected from a random sample of a working population participating in a longitudinal study of lung aging, using a 2:1 match of control subjects to cases, matching age, sex, ethnic origin, and smoking. Using a respiratory symptom questionnaire, spirometry, and the single-breath N2 test, we found no significant difference between heterozygotes and control subjects in terms of respiratory symptoms or pulmonary function data. We conclude that to 40 yr of age, the heterozygous phenotype (Pi MZ and MS) is not a risk factor for impairment of pulmonary function.

Adult↗

PubMed1979

The effect of smoking cessation on pulmonary function: a 30-month follow-up of two smoking cessation clinics.

To obtain further information about the effects of cessation of smoking on pulmonary function, we followed subjects who attended 2 smoking cessation clinics during a period of 30 months. This paper reports the results from 15 persons who succeeded in stopping smoking for the full 30-month period and from 42 who did not succeed for more than one month. Testing included a respiratory questionnaire, spirometry, and the single-breath N2 test. Standardized methods, the same equipment, and the same experienced personnel were used throughout the study. We found that forced vital capacity, one-second forced expiratory volume, closing volume as a percentage of vital capacity, closing capacity as a percentage of total lung capacity, and the slope of the alveolar plateau of the single-breath N2 test all improved significantly in the subjects who stopped smoking. This improvement continued for as long as 6 to 8 months, and then remained stable. There was no sex difference in the response to smoking cessation, nor could we find a threshold of function below which cessation did not result in improvement. On the contrary, those subjects with the greatest impairment initially showed the greatest improvement. Respiratory symptoms virtually disappeared in those who stopped smoking. Subjects who continued to smoke showed an initial improvement in some function tests, probably due to a marked decrease in consumption, but no significant improvement during the whole period. We concluded from this study that cessation of smoking results in definite improvement in pulmonary function, that there is greater improvement in persons who begin with impaired function than in those whose function is initially normal, that respiratory symptoms disappear rapidly.

Adult↗

PubMed1976

The effect of smoking cessation and modification on lung function.

The purpose of this study was to obtain more information about the effect on lung function of stopping smoking or of modifying the smoking habit and to determine the time course of change. We followed a group of 75 cigarette smokers who attended a smoking cessation clinic in May 1973, using a respiratory symptom questionnaire, spirometry, closing volumes, and the slope of the alveolar plateau of the single-breath nitrogen test. Subjects were tested before stopping smoking and at 1, 3, 6, and 12 months after the initial testing. We found a significant (P less than 0.05) improvement in closing volume as a percentage of vital capacity and closing capacity as a percentage of total lung capacity at 6 and 12 months and in the slope of the alveolar plateau at 1, 6, and 12 months in those who stopped smoking. There was also a dramatic decrease in respiratory symptoms in those who stopped smoking, a moderate decrease in those who reduced their consumption by at least 25 per cent, and very little change in those who did not appreciably modify their smoking consumption.

Adult↗