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Biomedical subjects

B A Mitchell

Publications and source records attributed to B A Mitchell.

10 recordsLinked to original sources
PubMed1995

Semiautomated quantitation of urinary protein and creatinine.

The application of personal computers to routine tasks such as the recording and manipulation of data can greatly increase the speed and accuracy of the analyses. This report describes the use of a Macintosh computer and a BioTek microplate reader for the analysis of urinary protein and creatinine. Previously published assay methods for protein and creatinine were adapted for analysis using 96-well microplates. The adapted assays had excellent linearity (r2 = 0.99), with reduced variability compared to the previous methods. This resulted in increased sensitivity as demonstrated by 95% confidence limits. In addition, reductions of both assay materials and sample sizes were realized. The direct connection of the computer and microplate reader reduced the time needed to record absorbance measurements and perform analyses when compared to the more common protocols and methods of analysis. The assay protocols, equipment and interface, data file management, and methods of analysis are described.

Albuminuria↗
PubMed1984

Prevalence of mastitis pathogens in herds participating in a mastitis control program.

Bacteriological data from herd surveys by the Massachusetts Mastitis Laboratory were analyzed. Comparisons of percent cows and quarters with major mastitis pathogens and types of bacteria isolated were between Streptococcus agalactiae-positive (1105 cows from 17 herds) and Streptococcus agalactiae-negative herds (1088 cows from 17 herds). Major mastitis pathogens were isolated from 58.5% of cows and 37.0% quarters in Streptococcus agalactiae-positive herds. The most frequently isolated bacteria were Streptococcus agalactiae and Staphylococcus aureus, and together these accounted for 87% of organisms isolated. In contrast, major mastitis pathogens were isolated from only 26.3% of cows and 10.2% of quarters in Streptococcus agalactiae negative herds. Streptococci other than Streptococcus agalactiae, Staphylococcus aureus, and coliforms were the predominant organisms isolated. Seventeen additional Streptococcus agalactiae negative herds were surveyed annually over 6 yr. An average of 25.8% of cows and 10.3% of quarters were positive for major mastitis pathogens during this time. The predominant bacteria isolated were streptococci other than Streptococcus agalactiae, Staphylococcus aureus, and coliforms. There was little variation between years.

Animals↗
PubMed1983

Susceptibility of bovine mammary gland to infections during the dry period.

Quarter foremilk samples (1,574) were collected for bacteriological analysis from 40 cows during late lactation, early involution, prior to parturition, parturition, and during early lactation. Six of 160 quarters were infected with major pathogens during late lactation. Twelve new infections occurred during early involution. Twenty-two quarters were infected at parturition. Of these infections, 12 occurred after early involution, and 10 infections that originated during early involution persisted throughout the dry period. During early lactation, 21 major pathogen infections were observed. Nine occurred after calving, and 12 persisted from parturition. Most major pathogen infections (93.8%) were caused by coliforms and streptococcal species other than Streptococcus agalactiae. Numbers of streptococcal infections were highest at parturition and early lactation. Numbers of quarters infected with coliforms were similar during early involution, parturition, and early lactation. Coagulase negative staphylococcal infections increased during the dry period, whereas Corynebacterium bovis infected quarters decreased. Udder infections were few in cows completing first or second dry periods. The incidence of udder infection was highest in cows completing third or later dry periods.

Animals↗
PubMed1983

Intramammary infections in primigravid heifers near parturition.

Mammary secretion from 32 primigravid heifers was obtained aseptically to determine frequency of bacterial isolation and incidence of intramammary infection near parturition. Quarter samples were collected 14 and 7 days prior to expected parturition, at parturition, and 7 and 14 days postparturition. Analysis of culture data indicated that 77.1% of samples were bacteriologically negative, and 15.7% contained coagulase negative staphylococci, 4.4% streptococci other than Streptococcus agalactiae, 3.8% coliforms, .8% coagulase positive staphylococci, and .1% Corynebacterium bovis. Frequency of bacterial isolation was highest in samples obtained prior to and at parturition. Thirty-five of 128 quarters were infected at parturition. Twenty-six of the 35 infections were caused by coagulase negative staphylococci, 4 by streptococci other than Streptococcus agalactiae, 4 by coliforms, and 1 by coagulase positive staphylococci. Twenty infections were observed during the early postpartum period. Coagulase negative staphylococcal infections decreased markedly. However, the number and type of primary pathogen infections during early lactation were similar to those at parturition.

Animals↗
PubMed1980

Variation of lactoferrin and mastitis and their heritabilities.

Analyses were of lactoferrin and mastitis of milk samples taken every other month from 830 Holstein cows in eight herds for 1 yr. Patterns of variation and amounts in lactation, colostrum, and dry period were similar to reports. In negative mastitis tests of milk samples, lactoferrin content was lower during lactation and lower as age of the cow advanced than for positive tests. However, heritability of mastitis was .14, whereas for lactoferrin was .44 in records of 289 cows. This latter is high enough to be useful but unreliable with large standard error .30. Several sire groups differed significantly.

Animals↗