Search PubMed⌕ Search

Biomedical subjects

D M Anderson

Publications and source records attributed to D M Anderson.

At least 127 records · Page 7Linked to original sources
PubMed1986

Transmission electron microscopy of jejunum, ileum, and caecum tissues from rats fed with gums arabic, karaya and tragacanth.

Transmission electron microscopy has been used to study the ultrastructure of rat jejunum, ileum and caecum after dietary supplementation with 10% (w/w) gum arabic, 7% (w/w) gum karaya, 4% (w/w) gum tragacanth for 45 days. Scrutiny of 65 micrographs, undertaken independently by 2 specialists, revealed no abnormalities in any of the organelles in any of the micrographs. Twelve representative micrographs are reproduced here.

Animals↗
PubMed1986

The effect of the polysaccharide composition and structure of dietary fibers on cecal fermentation and fecal excretion.

The fermentation of dietary fibers gives a clue to their mode of action. Wheat bran and gum tragacanth increase stool weight but have no effect on serum cholesterol or on hydrogen excretion. Gum arabic and pectin in the form of raw carrot have no effect on stool weight but decrease serum cholesterol and are associated with an increase in breath-hydrogen excretion. Other fiber sources like gum karaya have no effect on stool weight, serum cholesterol, or breath hydrogen. There are no correlations between the chemical composition and structure of the fibers studied and their physiological effects.

Breath Tests↗
PubMed1985

Frequency of milk expression and milk production by mothers of nonnursing premature neonates.

The relationship between frequency of expression and milk output was studied in 25 healthy mothers of premature infants with gestational ages at birth of 28 to 37 weeks. Mothers expressed milk from days 5 to 11 post partum based on card selection, either four or more times per day or three or less times per day using an electric pump. Based on a second card selection, milk expression was either maintained at the same frequency or changed to the opposite frequency for a second week. On days 11 and 18, all milk expressed was quantitated. Of the 25 mothers studied, nine mothers changed expression frequency from four or more times per day to three or less times per day or vice versa, while nine expressed at the same frequency both weeks. These data indicate that frequent expression was associated with a significantly greater milk production (342 +/- 229 mL) than infrequent expression (221 +/- 141 mL). Thus, a low-cost, noninvasive method of enhancing milk production by mothers of nonnursing, prematurely delivered infants was to encourage frequent milk expression.

Adult↗
PubMed1985

Bacteriostatic qualities of human milk.

A practical concern of the working mother is the bacteriostatic quality of human milk over time without benefit of refrigeration. Therefore, quantitative cultures of human milk stored at room temperature were performed at 0, 2, 4, 6, and 24 hours after expression. Milk from 10 mothers less than six days postpartum (colostrum) and from 10 mothers 7 to 42 weeks postpartum (mature milk) was studied. The number of colony-forming units per milliliter of milk cultured at 0 time did not significantly increase in mature milk after 6 hours nor in colostrum after 24 hours of storage at room temperature. Thus, mothers who express milk for their own infants while at work may assume that the bacterial contamination of their milk will not increase significantly for up to but no longer than 6 hours after expression, even if they have no access to refrigeration.

Adult↗
PubMed1985

Vitamin E and C concentrations in human milk with maternal megadosing: a case report.

Vitamins C and E were selected for analysis in this patient to study the effect of megavitamin ingestion on water-soluble and milk-fat-soluble vitamin concentration. This mother also had chronically consumed megadose amounts of vitamins A, B-6, B-12, and thiamin. Although these vitamins were not quantitated in her milk, one would anticipate that they were elevated, as were vitamins C and E. Long-term megavitamin intake of vitamins C and E, 40 and 99 times the RDAs, respectively, was associated with elevated blood and milk vitamin levels. The thesis that dietary water-soluble but not fat-soluble vitamins alter milk vitamin concentrations was not supported. Milk vitamin C levels were elevated above established norms, and milk vitamin E levels were more than three times the upper range of normal.

Adult↗
PubMed1984

Resistance to challenge and macrophage activity in mice previously vaccinated with formalin-killed Cryptococcus neoformans.

Mice were vaccinated with formalin-killed Cryptococcus neoformans either intranasally, intravenously, or intraperitoneally. Resistance to lethal challenge and in vitro phagocytic activity of alveolar and peritoneal macrophages was studied. Increased resistance to lethal challenge was seen following vaccination by each of the three routes but increased phagocytic activity was seen only in alveolar macrophages from mice vaccinated intranasally.

Administration, Intranasal↗
PubMed1984

Pulmonary cell response in mice following intranasal instillation with Cryptococcus neoformans.

Cryptococcus neoformans was instilled intranasally into mice which were sacrificed to determine the fate of instilled cryptococci and the pulmonary cellular response. During the first 12 h, instilled cryptococci decreased significantly in numbers and did not disseminate to extrapulmonary sites. There was a transient increase in neutrophils which may have been due to an influx of bacteria which accompanied the process of intranasal instillation.

Acinetobacter↗
PubMed1984

Interspersed poly(A) RNAs of amphibian oocytes are not translatable.

The poly(A) RNA of the Xenopus oocytes has been shown to include both single copy and interspersed transcripts. Interspersed maternal poly(A) RNAs contain repetitive sequence elements distributed within regions transcribed from single copy sequences. When renatured these RNAs form partially double-stranded RNA networks, and as shown earlier this can be utilized for preparative separation of interspersed maternal transcripts from maternal transcripts that remain single-stranded after renaturation (Anderson et al., 1982). The translational activity of these RNA fractions was tested in vitro, in wheat germ and reticulocyte systems. While the single-stranded fractions supported protein synthesis, the interspersed oocyte RNAs displayed little translational activity. Translational activity was measured in vivo by injection into the Xenopus oocyte. Oocytes previously injected with globin mRNA were injected with increasing amounts of single-stranded, double-stranded, or denatured double-stranded RNA fractions, and the amount of globin synthesis was determined. It was found that single-stranded RNA competes with globin mRNA for the limited translational apparatus of the oocyte, as manifested by a quantitative reduction of globin synthesis. However, globin synthesis was not affected when double-stranded RNA, either in renatured or denatured form, was injected. We conclude that the interspersed RNAs are not translated within the oocyte. The amount of single and double-stranded RNAs loaded onto polysomes in the injected oocytes was also determined. Sixty seven per cent of radio-iodinated single-stranded RNA pelleted with polysomes in injected oocytes, whereas less than 20% of similarly labeled double-stranded RNA pelleted with polysomes. This value is similar to that obtained when partially hydrolyzed RNA is injected, suggesting again that essentially none of the interspersed RNA is translated in vivo. The significance of these findings in relation to translational regulation during oogenesis and early development is discussed.

Animals↗
PubMed1984

The effects of dietary gum tragacanth in man.

Following a 7-day control period, 5 male volunteers consumed 9.9 g gum tragacanth (GT) daily for 21 days. The GT was well tolerated and there were no adverse effects in any of the volunteers. The daily intake was very high in relation to the minor amounts of GT (estimated at 2 g per person per annum) likely to be ingested as a foodstuffs additive. The wide range of measurements made before and at the end of the test period show that the ingestion of GT had no significant effect on any of the following: plasma biochemistry; haematological indices; urinalysis parameters; glucose tolerance; serum cholesterol, triglycerides and phospholipids; breath hydrogen and methane concentrations. The intestinal transit time decreased and faecal fat concentration increased (P less than 0.01) for 4 subjects. The faecal wet and dry weights increased in all subjects (P less than 0.01). These changes may be of nutritional and physiological interest but do not reflect any adverse toxicological effects arising from the ingestion of large daily doses of GT.

Adult↗
PubMed1984

Transmission electron microscopy of heart and liver tissues from rats fed with gums arabic and tragacanth.

Transmission electron microscopy has been used to examine the ultrastructure of rat hearts and livers after diet supplementation with (a) 0, 0.5, 1.5, 2.5 and 3.5% (w/w) gum tragacanth (GT) for 91 days, (b) 0 and 1% GT for 5 days (c) 0, 1, 4 and 8% (w/w) gum arabic (GA) for 28 days. The preparation and scrutiny of the electron micrographs was undertaken by two independent teams of specialists. There were no detectable abnormalities in any of the organelles in the heart and liver specimens from any of the test animals and no inclusions nor other pathological changes were observed. All micrographs showed normal, healthy tissues; particular attention was given to the mitochondria in hepatocytes as they serve as sensitive indicators of the health and state of activity of cells. In addition, the data obtained from assays of the microsomal protein and cytochrome P-450 content of the livers showed that GA and GT did not cause inductive effects. These results do not support earlier suggestions, based on in vitro assays, that GA and GT cause changes in the function of rat heart and liver mitochondria and liver microsomes; however, they confirm a report by Zbinden that the ingestion of GT does not produce abnormalities in the cardiac function of rats.

Animals↗
PubMed1984

Hypertrophic obstructive cardiomyopathy. Effects of acute and chronic verapamil treatment on left ventricular systolic and diastolic function.

Changes in left ventricular systolic and diastolic function and outflow gradient were evaluated in patients with obstructive hypertrophic cardiomyopathy after intravenous acute treatment with verapamil (15 patients) and after six months of oral chronic treatment (11 patients). All patients had severe symptoms despite beta blockade, and the condition of all but two improved appreciably after chronic treatment with verapamil. Resting left ventricular outflow tract gradient decreased in six of 15 patients after intravenous verapamil, and in five of 11 patients after long term treatment, but there was no change in provocable gradients nor any correlation between changes in gradient and improvement in symptoms. Left ventricular ejection rate did not change after intravenous or oral treatment. End systolic pressure/end systolic volume index remained unchanged after oral verapamil treatment. Whereas left ventricular total stroke volume index and end diastolic volume index increased without any significant change in left ventricular end diastolic pressure, indicating improved left ventricular diastolic function. In some patients the left ventricular diastolic pressure-volume curve shifted downwards or to the right or both. These findings suggest that improvement in symptoms with verapamil in patients with obstructive hypertrophic cardiomyopathy is unlikely to be related to changes in left ventricular outflow gradient or in systolic function and may be related to improved diastolic function.

Adolescent↗
PubMed1983

The effects of dietary gum karaya (Sterculia) in man.

Following a 7-day control period, 5 male volunteers consumed 10.5 g gum karaya (GK) daily for 21 days. Measurements before and at the end of the test period showed that the ingestion of GK had no significant effect on the following: intestinal transit time, faecal wet or dry weight, concentrations of faecal fat, total and individual volatile fatty acids, bile acids, and neutral sterols; breath hydrogen and methane concentrations; glucose tolerance; serum cholesterol, HDL cholesterol, triglycerides and phospholipids; plasma biochemistry; haematological indices; urinalysis parameters. The daily test intake, which was large in relation to the very minor amounts of GK used in foodstuffs, did not cause any toxic effects in terms of the wide range of measurements made; moreover the GK had no metabolic action of any consequence.

Administration, Oral↗
PubMed1983

A study of the effects of dietary gum arabic in humans.

Gum arabic administered to men for 3 wk has little effect on glucose tolerance and stool weight, but decreases the serum cholesterol. There was no significant increase in fecal bile acids and neutral sterols. Breath hydrogen increased only after chronic administration. Gum arabic could not be recovered from the stool which suggests metabolism of gum arabic in the colon.

Adult↗
PubMed1983

Length of gestation and nutritional composition of human milk.

A comparative analysis of the composition of milk produced during the first 14 days of lactation by mothers who deliver prematurely and those who deliver at term is described and these values are contrasted with the composition of donor milk specimens. Twenty-four-hour milk collections (days 3, 7, and 14 postpartum) were obtained from nine mothers delivered between 37 to 42 wk gestation (term) and from 14 mothers who delivered between 28 to 36 wk gestation (preterm). A single spot milk collection was obtained from nine mothers who were 6 to 10 months postpartum (donor). Term and preterm milk was compared on specific postpartum days using an analysis of covariance controlling for 24-h milk volume. The protein, carbohydrate, fat, and energy content varied in a similar fashion in term and preterm milk over the 14 postpartum days studied. Furthermore, there was no significant difference between the two milk groups on any single postpartum day evaluated in terms of protein, carbohydrate, fat, or energy concentration. The milk volumes were significantly greater from the mothers delivered at term on days 7 and 14 (p less than 0.01) and the protein content of both term and preterm milk was negatively correlated with milk volume (r = -0.6 or more on each day studied). The nutrient and energy composition of spot donor milk was highly variable and frequently quite different from either term or preterm 24-h milk collections. These data indicate that milk from mothers who deliver prematurely does not contain significantly different concentrations of nutrients or energy than milk from mothers delivered at term and suggest that the differences previously noted between the two groups may be related to 24-h milk volume.

Female↗