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Biomedical subjects

D G White

Publications and source records attributed to D G White.

126 records · Page 7Linked to original sources
PubMed1981

Current maternal attitudes to infant feeding methods.

Mothers' feeding practices and their attitudes to breast and bottle feeding were investigated. Sixty-four per cent started to breast feed and 35% continued past 2 months, a continuation rate which is higher than previously reported. Also higher than previously reported was the proportion of working class women breast feeding. This may reflect a current trend. Most women decided on their infant feeding technique early in pregnancy, and 80% followed that decision. For those who changed their minds about feeding practice postnatally, and for those who were initially undecided, the hospital was influential. Analysis of women's pleasurable and less restricting than they had anticipated. The results are discussed in relation to attempts to encourage breast feeding.

Attitude↗
PubMed1981

Interactions of mothers with their newborns in the first half-hour of life.

Eight first-time and eight second-time working class mothers were observed interacting with their newborn babies during the first half-hour of life. In all cases the father was present for at least some of this period. The interactions were notable for their passivity, mothers looked for long periods at their babies and engaged in some finger-tip touching of the babies face and head, but they engaged in very little exploration of the babies, few vocalizations and few expressive acts such as kissing. However, the presence of the father was associated with more intense mother-newborn interaction. First-time but not second-time fathers tended to be excluded from interaction with either the mother or the baby at this time. These results are discussed in the light of current thinking on mother-newborn bonding and the role of midwifery staff in promoting that bonding process.

Fathers↗
PubMed1980

The influence of ischaemia on the biliary tract.

Damage of the biliary tract at the end of a period of hepatic preservation prior to liver transplantation has been observed in man. This damage may be important in the development of early biliary complications. A model of hepatic biliary ischaemia in the pig has been developed which permits comparison between the influences of warm and cold ischaemic damage on the biliary tract. The major damage to the biliary tract in the pig in this model appears to occur after prolonged cold preservation.

Animals↗
PubMed1980

Laboratory screening for zearalenone formation in corn hybrids and inbreds.

Grains from 14 corn inbreds and 4 single cross hybrids were inoculated with 3 isolates of Gibberella zeae to determine their inhibition of zearalenone production. The corn hybrids: Pa762 x A632 (50 mg/kg zearalenone production), A619 x A632 (17 mg/kg zearalenone production), H95 x Mo17 (132 mg/kg zearalenone production), and B73 x MO17 (33 mg/kg zearalenone production) appear to have less resistance than the inbreds to toxin formation. Inbred H95 (64 mg/kg zearalenone production) supported the highest toxin production of all inbreds. The remaining 13 inbreds did not exceed 15 mg/kg zearalenone production. The inbreds A632 (4 mg/kg zearalenone production) and Pa762 (2 mg/kg zearalenone production) demonstrated some resistance; the resulting cross, hybrid Pa762 x A632 (50 mg/kg zearalenone production), does have greater resistance than hybrid H95 x Mo17 (132 mg/kg zearalenone production). Analysis of variance indicated highly significant variation between corn varieties and fungal isolates. The coefficient of variation for 29 fermentations run in duplicate on inoculated control corn to produce zearalenone (212 mg/kg) was 37%, which would include variation in both the fermentation and analysis. Isolate and variety interaction is not significant.

Fermentation↗
PubMed1975

Analysis of motor conduction velocity in the human median nerve by computer simulation of compound muscle action potentials.

A digital computer was used to reconstruct compound muscle action potentials recorded from the human thenar eminence after stimulation of the median nerve. The programme allowed the following parameters to be varied: (1) the dimensions of a representative single motor unit potential; (2) the number of motor units in the muscle and the range and distribution of conduction velocities in their nerve fibres; and (3) the distance along the nerve from the point of stimulation to the muscle. The reconstructed compound muscle action potentials were similar to real compound potentials recorded from normal subjects. The number of single motor units and the range of conduction velocities required for the reconstruction correlated with quantitative histologic studies of the recurrent branch of the median nerve to the thenar muscles. By altering the distribution of conduction velocities it was possible to study the effect of abnormal patterns of nerve conduction on the configuration of the simulated compound muscle action potentials. It was found that abnormally slow conduction caused an increased discrepancy between the main parameters of compound potentials corresponding to stimulation of the nerve at proximal and distal sites. These observations suggest that a careful analysis of the differences between pairs of compound muscle action potentials may provide a method for more detailed assessment of conduction velocity in clinical studies of peripheral nerve disorders.

Action Potentials↗
PubMedDate not supplied

The comparative effectiveness of three commercial oral solutions in correcting fluid, electrolyte and acid-base disturbances caused by calf diarrhoea.

Three commercial oral rehydration solutions (Effydral ('E'), Lectade ('L') and Lectade Plus ('LP')) were evaluated in young calves with diarrhoea following the administration of E. coli. Twenty calves with non-fatal diarrhoea were included in each group and examined for electrolytes, acidosis (pH, PCO2 and TCO2), PCV and selected biochemical parameters. Faecal consistency and clinical state were also assessed. Eight calves were examined for plasma and ECF volume. Calves were treated with the appropriate ORS only for 2 days and with ORS plus milk substitute for a further 2 days. No other treatments were given. Solutions E, L and LP were chosen specifically to test the hypothesis that their ability to repair extracellular volume would depend on their sodium content (E > L > LP) and their ability to correct metabolic acidosis would reflect their content of bicarbonate precursor (E > LP > L). Both hypotheses were confirmed as was the fact that the higher sodium content of E helps it to repair ECF volume without predisposing to hypernatraemia. The importance of correcting hyponatraemia as well as ECF volume is emphasized. Direct measurement of such changes proved much more sensitive than traditional clinical parameters such as weight loss, skin elasticity, etc. Although this study was not designed to examine mortality, it is noted that nine treated calves died, none in the E-treated group.

Acid-Base Imbalance↗
PubMedDate not supplied

Characterization of antibiotic-resistant bacteria in rendered animal products.

Antibiotics are used in food animal production to treat diseases and also to improve performance. Antibiotics are not used on all farms, and antibiotic resistance is occasionally found on farms that do not use antibiotics. Rendered animal protein products are often included in poultry feeds and could potentially serve as a source of antibiotic-resistant bacteria. One hundred sixty-five rendered animal protein products from cattle, poultry, and fish were aseptically collected from poultry feed mills. Fifty-five percent of the poultry meal samples had detectable levels of gram-negative bacteria ranging from 40 to 10,440 colony-forming units/g of sample. Poultry meal and meat and bone meal had the greatest number of samples with bacteria resistant to five or more antibiotics. A high percentage of feed samples (85%) contained bacteria resistant to amoxicillin, ampicillin, clavulanic acid, or cephalothin, whereas few samples contained bacteria resistant to ciprofloxacin, kanamycin, or trimethoprim/sulfamethoxazole. Acinetobacter calcoaceticus, Citrobacter freundii, and Enterobacter cloacae were the most commonly isolated antibiotic-resistant bacteria. Isolation for Salmonella was also performed, with 14% of the meat and bone meal samples containing Salmonella sp. Only one of the meat and bone meal isolates, Salmonella livingstone, was resistant to five or more antibiotics. Many of the antibiotic-resistant bacteria contained integrons, genetic elements that mediate multiple drug resistance.

Animal Feed↗
PubMedDate not supplied

Virulence factors of Escherichia coli associated with colisepticemia in chickens and turkeys.

Four hundred twenty turkey and 80 chicken Escherichia coli isolates from colisepticemic birds were examined for the following properties: heat-labile toxin (LT), heat-stable enterotoxin, verotoxin, colicinogenicity, hemolysin, and hydroxamate/aerobactin production. Twenty-four (5.7%) of the 420 turkey isolates and six (7.5%) of the 80 chicken isolates produced an LT that was cytotoxic for both Vero and Y-1 cells. In contrast, 48 (11.4%) of the turkey isolates and 18 (22.5%) of the chicken isolates produced a distinct LT that was cytotoxic only for Vero cells. In addition, 64 (80.0%) of the chicken isolates and 309 (74.0%) of the turkey isolates produced aerobactin. Colicinogenicity occurred in 51 (64.0%) of the chicken isolates, with 41 (51.0%) producing colicin V. By contrast, 254 (61.0%) of the turkey isolates produced a colicin, of which 176 (42.0%) produced colicin V. None of the chicken and turkey isolates produced hemolysin or heat-stable enterotoxin.

Animals↗
PubMedDate not supplied

Rapid thin layer chromatographic method for determination of zearalenone and zearalenol in grains and animal feeds.

A rapid and inexpensive method has been developed for the analysis of zearalenone and zearalenol in grains and animal feeds. The method involves extraction with 75% methanol, precipitation of pigments with lead acetate, and defatting with petroleum ether. The mycotoxins are subsequently partitioned into toluene-ethyl acetate, chromatographed on high performance thin layer chromatographic plates, and detected after treatment with Fast Violet B salt solution. Sensitivity of the method is better than 80 ng/g for zearalenone and 200 ng/g for zearalenol. Ten samples can be completed in less than 2 h. The method is applicable for zearalenone in corn, wheat, barley, millet, and swine feeds.

Animal Feed↗