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Biomedical subjects

G T Goodman

Publications and source records attributed to G T Goodman.

At least 19 recordsLinked to original sources
PubMed1987

Seasonal variation of serum lipids in the vervet monkey.

Seasonal variation of serum lipids has been observed in man, primates and other species. We are presenting data on serum lipid variation in Vervet monkeys (Cercopithecus aethiops). The monkeys (54 males, 33 females) were fed control diets (commercial pellets, fruit, vegetables) and data were pooled and grouped by season. Data having been obtained in South Africa, the seasons were: summer (December, January, February); fall (March, April, May); winter (June, July, August); and spring (September, October, November). Data presented are based on multiple samplings. Total serum cholesterol (mg/dl) and beta-lipoprotein cholesterol (mg/dl) varied significantly with season, peak values being observed in the fall months. Triglyceride and alpha-lipoprotein cholesterol levels showed seasonal variation which was not statistically significant. However, when data were analyzed by weight group (less than 3.3 kg; 3.3-4.3 kg; 4.4-5.3 kg; greater than 5.4 kg) only triglyceride and alpha-lipoprotein levels varied significantly with season. Significant interactions between diet, sex, weight, and season have also been observed. These observations can be used in planning future studies.

Animals↗
PubMed1986

Influence of dietary fiber on lipids and aortic composition of vervet monkeys.

A semipurified, cholesterol-free diet containing 40% carbohydrate can produce aortic sudanophilia or aortic atherosclerosis in vervet monkeys (Cercopithecus aethiops pygerethrus) depending on the particular carbohydrate fed. Four groups of vervet monkeys (three males and three females per group) were fed semipurified diets containing lactose. Two of the groups were also fed 15% cellulose (C) or 15% cellulose plus 0.1% cholesterol (CC); the two other groups were fed 15% pectin (P) or 15% pectin plus 0.1% cholesterol (PC). The average serum total cholesterol and low density lipoprotein cholesterol levels over the entire feeding period (mg/dl +/- SEM) were, for C, 156 +/- 14 and 95 +/- 5; for P, 173 +/- 15 and 112 +/- 8; for CC, 187 +/- 27 and 122 +/- 21; and for PC, 155 +/- 11 and 108 +/- 7. Cholesterol levels at autopsy (mg/dl +/- SEM) were, for C, 103 +/- 6; for P, 108 +/- 16; for CC, 92 +/- 9; and for PC, 106 +/- 7. Aortic sudanophilia (percentage of area) was, for C, 5.9 +/- 2.7; for P, 13.5 +/- 9.4; for CC, 5.3 +/- 2.1; and for PC, 21.6 +/- 10.3. Dietary pectin led to more severe sudanophilia (increased by 129% in the absence of cholesterol and by 308% in its presence) than did cellulose. Analysis of aortic glycosaminoglycans (GAG) revealed that dermatan sulfate levels fell in both cholesterol-fed groups, and chondroitin sulfate fell in aortas of group CC. Heparan sulfate levels were unaffected by cholesterol feeding. Hexuronic acid, galactosamine and hexosamine levels were elevated in the pectin-fed monkeys, but levels were unaffected by dietary cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Comparison of plasma profiles of oxytocin and prolactin following suckling in the rat.

The purpose of these studies was to determine the effect of suckling on the plasma oxytocin (OT) concentration profile in conscious primiparous rats during midlactation. Comparisons were made with plasma prolactin (PRL) levels obtained in the same rats. OT levels in the majority of rats exhibited a single peak during the first 5-30 min, then fell rapidly during the course of a 45-min period of suckling. The plasma OT levels were sustained over a longer period in mothers suckling 8 rather than 6 pups; the amplitudes of the OT response were similar, however. By contrast, plasma PRL profiles indicated that a steady secretion of the hormone occurred throughout the suckling period, with suckling of 8 pups resulting in significantly higher plasma levels than suckling of 6 pups. A considerably greater increase in the peak plasma OT concentration resulted when hungry foster litters of 6 pups were suckled after the mothers' own 6 pups had been suckled. Plasma PRL levels during the two sucklings, though, were similar. The rapid onset of the OT response to suckling was seen more clearly in urethane-anesthetized rats following mammary nerve stimulation. Plasma OT levels rose to a peak within 5 s after the onset, then fell to prestimulus levels by the end of the 65-second stimulation period. These results suggest that different regulating mechanisms are involved in the secretory responses of OT and PRL to suckling and that different thresholds of activation are likely to exist for the two hormones.

Animals↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Dietary cholesterol, beta-sitosterol, and stigmasterol.

Cholesterol and fat are implicated as dietary factors enhancing the risk for colon carcinogenesis. Plant sterols such as beta-sitosterol when added to diets of experimental animals treated with colon carcinogens reduce tumor yields and counteract the proliferative changes associated with carcinogenesis. The question of whether the diet of human populations at low risk for colon cancer is mirrored in their sterol composition is addressed in this study. Four study groups consisting of 18 Seventh-day Adventist (SDA) pure vegetarians, 50 SDA lacto-ovo vegetarians, 50 SDA nonvegetarians, and 50 general population nonvegetarians were selected from the greater Los Angeles basin, and 3-day composite diets were analyzed for their sterol composition. The most significant index of dietary sterol status is the ratio, beta-sitosterol + stigmasterol/cholesterol (plant sterol/cholesterol ratio). The values for the four groups ranged from 0.49 to 16.0 (general population nonvegetarians = 0.49; SDA-nonvegetarians = 0.98; SDA lacto-ovo vegetarians = 3.26; SDA pure vegetarians = 16.0). The data also show that the absolute amounts of cholesterol consumed as a factor by itself might not be as significant as its relationship to total plant sterols in the diet.

Adult↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Metabolism of neutral sterols.

Cholesterol and its metabolites, together with bile acids, are implicated as risk factors in the genesis and progression of colon cancer. This study was designed to determine differences in the neutral sterol composition of stools from four different population groups differing in their dietary habits as well as in their expected rates for colon cancer. Four study groups consisting of 18 Seventh-day Adventist (SDA) pure vegetarians, 50 SDA lacto-ovo vegetarians, 50 SDA nonvegetarians, and 50 general population nonvegetarians were selected from the greater Los Angeles Basin area. Three-day composite stool samples were lyophilized and then analyzed for their neutral sterol composition. Cholesterol excretion values consistently showed an age-dependent peak in 46- to 50-yr age group for the total population, SDA lacto-ovo vegetarian and SDA-nonvegetarian subgroups being the principal contributors to this age-dependent phenomenon. The SDA pure vegetarians exhibited the lowest fecal concentrations and daily excretion of cholesterol as expected since their intake of dietary cholesterol is insignificant. Among the other SDA, regardless of whether they are lacto-ovo vegetarians or nonvegetarians, their cholesterol excretion patterns were similar but higher than in the nonvegetarians from the general population. Since dietary intakes of cholesterol are not significantly different among the two nonvegetarian groups, the differences in excretion values are attributable to differences in colonic metabolism. The ratio of cholesterol/cholesterol metabolites showed generally lower values among nonvegetarians compared to the matched group of lacto-ovo vegetarians. The observation was made that fecal cholesterol and its metabolites tend to be higher among nonvegetarians compared to those in the corresponding vegetarian groups.

Adult↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Metabolism of bile acids.

High levels of fecal bile acids have been associated with populations at high risk for developing colon cancer. In this study, 168 subjects were drawn from populations that show low and high mortality from colon cancer [pure vegetarians, lacto-ovo vegetarians, and nonvegetarians Seventh-day Adventists (SDA) and demographically comparable group from the general population]. Lyophilized aliquots of 3-day stool samples were examined for levels of primary (cholic and chenodeoxycholic acids) and secondary (deoxycholic and lithocholic acids) bile acids. Total bile acids (mg/g lyophilized stools) were statistically different among dietary groups: SDA pure vegetarians 2.16 +/- 0.32, SDA lacto-ovo vegetarians 3.66 +/- 0.41, SDA nonvegetarians 4.39 +/- 0.44, general population nonvegetarians 6.04 +/- 0.75; but were similar when stool weights, body weights, and fat intake were taken into account. The most striking difference was evident in the ratio of secondary to primary bile acids: when compared to SDA pure vegetarians, both SDA lacto-ovo vegetarians and SDA nonvegetarians had twice the ratio while values for general population nonvegetarians were five to six times. The data indicate that these differences in excretion patterns among dietary groups reveal distinctly characteristic metabolic features associated with diet and lifestyle.

Adult↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Composition, intake, and excretion of fiber constituents.

The role of fiber in human diet in preventing a number of chronic diseases has been a widely debated topic in recent years. The claim that populations at low risk for colon cancer generally consume a more fiber-rich diet than those at high risk, has been used to postulate a protective role for this group of substances. In this study we asked the question whether populations leading different dietary lifestyles and who are at varying risks for colon cancer show marked differences in their dietary and fecal profiles of various fiber components. Four study groups consisting of Seventh-day Adventist (SDA) pure vegetarians, SDA lacto-ovo vegetarians, SDA nonvegetarians, and a group of general population nonvegetarians were selected from the greater Los Angeles Basin area. Three-day composite diets, and stools were analyzed for neutral detergent fiber (NDF), hemi-cellulose, lignin, cellulose, cutin + silica, and pectin. The percentage composition and the daily intake and output of each of these components were computed for each population group. The dietary profile revealed a trend (not statistically significant) toward generally higher daily intake values among the vegetarian subgroups, neutral detergent fiber values in g/day: SDA pure vegetarians, 63.0 +/- 7.9; SDA-lacto-ovo vegetarians, 55.8 +/- 3.5; SDA nonvegetarians, 57.2 +/- 3.5; general population nonvegetarians, 52.5 +/- 4.9), lignin, cellulose, and pectin being the major contributors to this difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Binding of bile salts to dietary residues.

The binding of glycocholic and glycochenodeoxycholic acids to dried defatted residues of homogenized diets consumed by four dietary groups has been measured. The four groups were true vegetarian Seventh-day Adventists (SDA), lacto-ovo vegetarian SDA, nonvegetarian SDA, and the general population. Glycocholic acid was bound to the same extent (7 to 9%) by all four dietary residues. The true vegetarian SDA residues bound significantly more glycochenodeoxycholic acid than those of either lacto-ovo vegetarian SDA (p less than 0.001) or nonvegetarian SDA (p less than 0.001). The general population residue bound significantly more glycochenodeoxycholic acid than did those of nonvegetarian SDA (p less than 0.001). Binding of glycochenodeoxycholic acid was significantly correlated with dietary neutral detergent fiber (p less than 0.001), hemicellulose (p less than 0.01) and cellulose (p = 0.01). There was no correlation between the binding of glycochenodeoxycholic acid and dietary lignin, pectin, or cutin.

Adult↗
PubMed1984

Diet, nutrition intake, and metabolism in populations at high and low risk for colon cancer. Comparison of serum hexosaminidase levels.

Elevated levels of serum hexosaminidase (beta-2-acetamido-2-deoxy-D-glucoside; N-acetamidodeoxy-D-glucohydrolase, EC 3.2.1.30)(HEX) have been found in patients with cancer. In view of the reported low levels of colon cancer among Seventh-day Adventists (SDA) we determined levels of total HEX, and its heat-labile (HEX-A) and heat-stable (HEX-B) isozymes in vegetarian SDA, lacto-ovo vegetarian SDA, nonvegetarian SDA, and the general public. Lowest levels of total HEX and highest percentage of HEX-B were found in vegetarian SDA. The levels in the other three groups were comparable, and these differences were seen at all age levels. Female subjects exhibited significantly lower total HEX levels than the males but the percentage of HEX-B was the same.

Adult↗
PubMed1983

Neuroendocrine control of the milk ejection reflex.

The rate and extent to which milk is ejected from the mammary gland during suckling or milking depend upon the relative functioning of a complex array of facilitatory and inhibitory factors which are intertwined and capable of adapting. Some of these operate to regulate the release of oxytocin from the neurohypophysis; others function peripherally to regulate the contractile effectiveness of the oxytocin-sensitive myoepithelium within the mammary gland.

Animals↗
PubMed1981

Prolactin regulation of cytological differentiation of mammary epithelial cells in periparturient cows.

The influence of periparturient secretion of PRL on cytological differentiation of mammary epithelial cells was studied in 17 multiparous, monotocous Holstein cows. Mammary tissue was obtained 10 days prepartum and 10 days postpartum from untreated cows and from cows treated with CB154 (2-Br-alpha-ergokryptin) or CB154 plus PRL. CB154 was administered from 12 days before expected parturition through 10 days postpartum to reduce serum PRL concentrations, whereas exogenous PRL was administered for 6 days during the periparturient period to mimic the normal periparturient surge of the hormone. On day 10 postpartum, mammary epithelial cells of cows given CB154 alone were classified 18% undifferentiated, 65% intermediately differentiated, and 18% fully differentiated. In contrast, there were no undifferentiated epithelial cells in either postpartum controls or cows treated with CB154 plus PRL, and 73% and 79% of epithelial cells, respectively, were fully differentiated. Ultrastructural analysis demonstrated a relative lack of cellular differentiation in cows given CB154 alone. Specifically, the rough endoplasmic reticulum occupied 24% and 27% of the epithelial cell area in postpartum controls and cows treated with CB154 plus PRL, respectively; but the rough endoplasmic reticulum occupied only 16% of the cellular area in cows treated with CB154 alone (P less than 0.01). The relative area occupied by Golgi membranes and vacuoles was approximately 11% lower (P less than 0.01) in cows treated with CB154 than in lactating controls or cows that received PRL replacement therapy. The data demonstrate that periparturient secretion of PRL is necessary for complete structural differentiation of bovine mammary alveolar epithelium.

Animals↗
PubMed1977

The influence of long term estrogen treatment on plasma prolactin levels induced by ether anesthesia in ovariectomized rats.

2 methods of continuous estrogen delivery, polyestradiol phosphate injection and implantation of Silastic capsules of estradiol-17 beta, in ovariectomized rats induced increases in plasma prolactin in the afternoon (15.00-17.00) beginning at 1 week and continuing for 4-8 weeks. In addition these methods of estrogen treatment potentiated the ether-induced increase in plasma prolactin in the morning (9.00-11.00) beginning on week 2 and continuing for 3-8 weeks. These results indicate that estrogen activates the mechanisms that cause an afternoon surge in prolactin before potentiating a morning elevation induced by ether anesthesia.

Anesthesia↗