PubMed Health⌕ Search

Biomedical subjects

G M Fischer

Publications and source records attributed to G M Fischer.

At least 37 records · Page 2Linked to original sources
PubMed1981

Increased synthesis of aortic collagen and elastin in experimental atherosclerosis. Inhibition by contraceptive steroids.

Rabbits were fed an atherogenic or normal control diet for 3 months; half of each group were treated with mestranol--norethynodrel (M--N) and half with cottonseed oil vehicle. At the end of the 3-month period rabbits were killed and aortic collagen and elastin synthesis determine. Collagen and elastin synthesis was increased in aortas of rabbits on an atherogenic diet, but those treated with M--N had a lower rate of collagen synthesis and less deposition of cholesterol in the aorta than those administered cottonseed oil. It is suggested that long-term administration of the contraceptive steroid combination may retard the progression of atherosclerosis through the hormone's effect on vascular connective tissue.

Animals↗
PubMed1980

Increased vascular collagen and elastin synthesis in experimental atherosclerosis in the rabbit. Variation in synthesis among major vessels.

Collagen and elastin synthesis was determined in 5 regions of the vascular system in rabbits on (a) normal diet and (b) atherogenic diet. Increased connective tissue synthesis was found in 3 different sections of the aorta and in the pulmonary artery of rabbits on the atherogenic diet. The inferior vena cava showed no difference between the two groups. Regional variation in connective tissue synthesis was found in both normal and atherosclerotic animals, the vessels associated with the greatest degree of pulsatile distention in vivo having the greatest synthesis and the inferior vena cava, a low pressure, low distention vessel having the lowest synthesis. It is concluded that the atherogenic process includes stimulation of collagen and elastin synthesis. It is suggested that in addition to the effect of pressure on connective tissue synthesis, pulsatile distention may be a factor in synthesis and may be related to lesion formation.

Animals↗
PubMed1980

Pulsatile distention and vascular collagen synthesis in the rabbit.

In rabbits, collagen synthesis was studied in five different regions of the vasuclar tree which are subjected to different degrees of pulsatile distention, i.e., cyclic stretching, and mean pressure. The vessels with greatest pulsatile distention had the highest specific activity of hydroxyproline in collagen after incubation with 14C-proline and the inferior vena cava with low pressure and negligible pulsatile distention had the lowest specific activity. The findings suggest a link between mechanical stretching and cellular metabolic function and have significance as to the relationship of pulsatile flow to normal vascular and organ physiology.

Animals↗
PubMed1980

Plasma lipid levels and systolic blood pressure in ovariectomized and intact rats treated with contraceptive and other sex steroids.

Ovariectomized rats were treated for three weeks with cottonseed oil, estraiol, progesterone, mestranol-norethynodrel, or testosterone, and intact female rats were treated with cottonseed oil, or testosterone. Plasma total cholesterol, plasma triglycerides, and systolic blood pressure were then measured. Estradiol administration resulted in an increase in plasma cholesterol and triglycerides. Administration of testosterone to intact rats produced a decrease in cholesterol. Rats administered estradiol had significantly higher systolic blood pressure than any other group except the contraceptive treated group. By use of the ovariectomized rat model, the individual effects of sex hormones are delineated and it is demonstrated that estrogen has more effect than progestogen on both plasma lipids and systolic blood pressure.

Animals↗
PubMed1977

Effect of sex hormones on blood pressure and vascular connective tissue in castrated and noncastrated male rats.

Aortic collagen and elastin were quantitated in three groups of castrated and two groups of noncastrated male rats treated by intramuscular injection for 3 wk with oil, testosterone, or estradiol. The greatest differences were found between the castrated rats receiving testosterone and those receiving estradiol, the estradiol-treated rats having significantly lower total collagen, percent collagen, total elastin, and collagen/elastin (C/E), and higher percent elastin than those rats receiving testosterone. In noncastrated rats, administration of estradiol resulted in significantly lower total collagen, percent collagen, total elastin, and C/E. Systolic blood pressure was highest in rats receiving testerone and lowest in rats receiving estradiol. It is concluded that 1) estradiol in the presence or absence of testosterone decreases total accumulation of vascular connective tissue and alters the proportions of collagen and elastin so that the vessel is more distensible, 2) testosterone has an opposite but less marked effect than estradiol on vascular connective tissue, and 3) estradiol and testosterone alter blood pressure in opposite directions in the male rat.

Animals↗
PubMed1976

Plasma cadmium and zinc in human hypertension.

1. Plasma cadmium and zinc were determined by atomic absorption spectrophotometry in inferior venal caval or peripheral venous blood in thrity hypertensive patients and fifteen normal subjects. 2. The mean plasma cadium in hypertensive patients was significantly higher than in normal control subjects. 3. The plasma cadmium/zinc ratio was significantly greater in hypertensive patients. 4. There was a significant positive correlation between the plasma cadmium/zinc ratio and the mean arterial blood pressure.

Adult↗
PubMed1975

Altered arterial connective tissue in racing greyhound dogs.

Vascular collagen and elastin contents and the ratio of collagen/elastin (C/E) were studied in racing greyhound dogs, a breed which exhibits increased cardiac output. As compared to mongrel dogs, vascular C/E was lower, suggesting a greater distensibility of vessels as an adaptive response to hemodynamic stress.

Animals↗