PubMed Health⌕ Search

Biomedical subjects

R Fuller

Publications and source records attributed to R Fuller.

At least 73 records · Page 4Linked to original sources
PubMed1987

[Selectivity of rural migrants from the Sierra of Ecuador].

"This paper examines characteristics of recent rural-urban out-migrants leaving households in the Sierra of Ecuador. A large, household survey focussing specifically on migration is utilized, allowing detailed crosstabulations by sex and origin-destination combination and providing information about migrants generally not found in more generic surveys or censuses. Differences are noted between migrants and non-migrants in basic demographic characteristics, reasons for migrating, and economic activities prior to and subsequent to moving. Differences in the characteristics of migrants moving between various types of place of origin and place of destination are also noted." (SUMMARY IN ENG)

Americas↗
PubMed1987

The impact of origin community characteristics on rural-urban out-migration in a developing country.

It is widely believed that structural variables such as inequitable land distribution, lack of rural employment opportunities, and rural-urban wage and amenity gaps influence population movements in developing countries. Yet quantitative evidence is scant. In this paper a multilevel model is used to investigate the effects of individual-, household-, and areal-level factors on rural-urban out-migration in the Ecuadorian Sierra. Data from a detailed survey carried out in 1977-1978 and from government macro-areal statistics are used to investigate factors affecting the out-migration of youths aged 12-25. Preliminary conclusions are presented on the usefulness of multilevel models in studying migration and policy implications for Ecuador.

Adolescent↗
PubMed1986

Probiotics.

Explore the source record for details and available documents.

Animals↗
PubMed1985

Quantitation of zinc in nitric acid-digested plasma by atomic absorption spectrophotometry.

Human plasma, digested in a screw-capped Teflon vial for 1 h at 130 degrees C in concentrated nitric acid, is assayed for zinc by atomic absorption spectrophotometry using a single-slot, 10-cm burner and air/acetylene flame. The assay is linear to 10.00 mg Zn/liter, recovery averages 100.9%, and inter- and intraassay coefficients of variation are 5.9 and 1.9%. With this method, there is no burner clogging or adjustment necessary for sample viscosity. Sodium chloride does not interfere with the assay. The linear regression data of the standard curve for milligrams of Zn per liter (x) and milliabsorbance units (y) is y = 40x + 0.001.

Humans↗
PubMed1985

The influence of the host on expression of intestinal microbial enzyme activities involved in metabolism of foreign compounds.

The activities of four enzymes (beta-glucuronidase, nitrate reductase and nitroreductase) in selected intestinal bacteria (Escherichia coli, Clostridium sp., Streptococcus sp., Bacteroides sp. and Lactobacillus salivarius) were measured after growth in vitro and in vivo. The five strains differed in their activities with Clostridium sp. being the most active for beta-glucosidase, beta-glucuronidase and nitroreductase, and E. coli the most active producer of nitrate reductase. Enzyme activity in vivo tended to be higher than in vitro but there were instances where the comparative activities were reversed.

Animals↗
PubMed1985

Intestinal bacteria--passengers or partners?

The gut of all warm-blooded animals contains a large population of bacteria. The metabolic activities of this diverse collection of bacteria can affect the host animal in a variety of ways, some of which are harmful and some of which are beneficial. The way in which an organism reacts with its host can be affected by diet or by other bacteria present in the gut. The complex inter-relationship between the different bacteria and between the bacteria and the host are discussed.

Animal Nutritional Physiological Phenomena↗
PubMed1984

Bile acid deconjugation and attachment of chicken gut bacteria: their possible role in growth depression.

Bacteria isolated from the chicken gut were tested for their ability to deconjugate bile acids and attach to chicken epithelial cells (crop squamous cells and duodenal brush borders). Clostridium perfringens, streptococci and some of the bifidobacteria and lactobacilli were able to deconjugate all 4 substrates whereas the bacteroides deconjugated only the taurine conjugates and the coliforms were completely inactive. None of the strains of Escherichia coli or streptococci attached to squamous cells, but the anaerogenic coliform, the strain of Klebsiella aerogenes and the lactobacilli did show attachment. Attachment to brush borders was obtained with the anaerogenic coliforms, K. aerogenes, 2 out of 5 of the lactobacilli, and 4 out of 9 of the streptococci, but none of the strains of E. coli.

Adhesiveness↗
PubMed1984

The effect of yoghurt on some components of the gut microflora and on the metabolism of lactose in the rat.

Feeding yoghurt or base milk (from which the yoghurt was prepared by fermentation) to rats increased the counts of coliforms in the gut whereas the counts of lactobacilli were reduced by yoghurt but not by the base milk. Lactobacillus bulgaricus survived in the guts of gnotobiotic and conventional rats when yoghurt was fed continuously. Streptococcus thermophilus also survived in gnotobiotic rats but its ability to survive in conventional rats could not be examined. Both organisms failed to colonise the gut when a small inoculum of yoghurt was administered orally to germfree rats maintained on the stock diet. Streptococcus thermophilus but not Lact. bulgaricus grew in the rat diet when tested in vitro. Two enzyme systems (beta-galactosidase and lactase) were studied using, respectively, o-nitrophenyl-beta-D-galactopyranoside (ONPG) and lactose as the test substrates. Enzyme levels estimated with both substrates increased in the gut contents when rats were fed yoghurt but an increase was only found with ONPG in the intestinal mucosa fraction. The bacterial origin of all this increased activity is discussed. The other lactose-containing diets did not affect enzyme activity to the same degree. Feeding yoghurt changed the lactobacillus flora from one which was predominantly heterofermentative (Lact. reuteri ) to one which was predominantly homofermentative (Lact. salivarius).

Animals↗
PubMed1984

The adhesion of coagulase negative staphylococci to human skin and its relevance to the bacterial flora of milk.

Twenty-eight isolates of coagulase negative staphylococci were obtained from nipple swabs provided by one non-lactating woman and five nursing mothers. All but two of these isolates were shown by scanning electron microscopy to adhere to the surface of human skin. Experiments with frozen sections of human skin confirmed and extended these results by showing that isolates exhibited one of three patterns of adhesion, suggesting that there are three different adhesion receptors on epidermal cells. It is proposed that adhesion of staphylococci to the nipple and areolar epidermis provides a mechanism whereby large numbers of bacteria, nourished by residues of milk and saliva, are maintained on the surface of the skin.

Adhesiveness↗
PubMed1983

Compliance with disulfiram treatment of alcoholism.

One hundred twenty-four men were randomly assigned to receive disulfiram with a riboflavin marker or riboflavin alone. During a one year follow-up urine specimens were collected at each visit and analyzed for riboflavin. There was a strong relationship between excellent attendance and infrequent drinking. For subjects taking disulfiram there was a high correlation between a subject submitting 15 or more positive urines during follow-up and infrequent drinking. For the disulfiram patients there was also a strong relationship between continuous usage of disulfiram and infrequent drinking. However, the correlation between percentage of urine specimens positive for the riboflavin marker and infrequent drinking was slight. This occurred because a person who was drinking tended to return for follow-up only when he was not drinking and thus submitted only a few specimens of which the majority were positive. We conclude that (1) excellent attendance, (2) submission of a large number of positive urines and (3) a period of continuous compliance to the disulfiram regimen were highly associated with infrequent drinking.

Adult↗
PubMed1983

Trace-nutrient-binding proteins in milk and the growth of bacteria in the gut of infant rabbits.

1. The influence of trace-nutrient-binding proteins on the growth of coliforms, streptococci and lactobacilli in the gastrointestinal tract was examined in neonatal rabbits delivered germ-free and dosed with an artificial flora (ESL), or born conventionally and dosed with ESL or rabbit faeces. 2. In the stomach and small intestine of both gnotobiotic and conventional animals the counts of coliforms were usually atypically high and those of streptococci were always low. In the colon the counts of coliforms and streptococci were high. Lactobacilli usually became established in the gut of the gnotobiotic animals but were not found in the conventional rabbits. 3. Sterilization (freeze-drying followed by gamma-irradiation) of the milk decreased its capacity to bind added iron by 45% and vitamin B12 by 30%. When compared with raw milk, feeding of radiation-sterilized milk did not affect the viable count of coliforms and streptococci in the gut of gnotobiotic animals. 4. Saturating the nutrient-feeding proteins in milk with Fe, folic acid and vitamin B12 had no effect on the numbers of coliforms, streptococci and lactobacilli recovered from the intestine.

Animals↗
PubMed1983

The activities of amylase and a trypsin-like protease in the gut contents of germ-free and conventional chickens.

1. Proteolytic and amylase activities were assayed in the gut contents of germ-free and conventional chickens aged 3 and 14 d. 2. The tendency was for the proteolytic activity to be increased and the amylase activity to be decreased in conventional chicks. These differences were statistically significant in the caecum. 3. All of the additional proteolytic activity detectable in the caecum of conventional chicks was inhibited by soybean trypsin inhibitor. However, the increased activity was not detectable in the small intestine and was, therefore, not due to pancreatic trypsin. 4. Attempts to demonstrate in vitro bacterial production of a trypsin-like enzyme were unsuccessful.

Amylases↗