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A J Guidry

Publications and source records attributed to A J Guidry.

71 records · Page 4Linked to original sources
PubMed1979

Improved methodology for quantitative determination of serum and milk proteins by single radial immunodiffusion.

Single radial immunodiffusion is a simple inexpensive method for quantitating specific proteins in a heterogenous mixture. However, it has been criticized for its lack of accuracy and repeatability; coefficients of variation of 25% have been reported by some workers. We have adopted several refinements to the single radial immunodiffusion techniques which have appeared in the literature and have made several innovations of our own. Also, as an integral part of the technique, we have developed a computer program that determines the best-fitting curve for a given set of standards, applies this curve to the raw ring-diameters, and corrects the data for plate variation and sample dilution. This program has reduced errors greatly in calculating protein concentration since all data handling beyond the recording of the precipitant ring diameter is by computer. It also allows for the storage, retrieval, and analysis of large volumes of data on many different proteins simultaneously. The overall result of this system has been to decrease the coefficients of variation to below 5% for all the milk and serum proteins tested.

Animals↗
PubMed1977

Enhancement of chemotactic response of polymorphonuclear leukocytes into the mammary gland and isolation from milk.

Intramammary infusion of saline containing .1% glycogen resulted in diapedesis of numerous leukocytes (93% polymorphonuclear leukocytes) into milk. Direct microscopic somatic cell counts of primary milk 11 h after infusion with 100 ml of either saline containing .1% glycogen, saline, distilled water, or noninfused averaged 4.17, 1.06, .05, and .10 X 10(6) cells/ml of milk. Four times more polymorphonuclear leukocytes were isolated from residual milk (6.1 X 10(9) cells) collected 11 h following infusion than from primary milk (1.5 X 10(9)). The polymorphonuclear leukocytes isolated from either the primary or residual milk collected 11 h after infusion of saline containing .1% glycogen phagocytosed Staphylococcus aureus with great avidity. Sixty-eight percent of a culture of heat-killed phosphorus-32-labeled Staphylococcus auresu (400 X 10(6)) were phagocytosed within 60 min by 25 X 10(6) polymorphonuclear leukocytes. When isolated polymorphonuclear leukocytes were incubated with live Staphylococcus aureus, 98% of the ingested organisms were killed. Isolation of polymorphonuclear leukocytes from residual milk 11 h after intramammary infusion of saline containing .1% glycogen will provide large numbers of polymorphonuclear leukocytes for in vitro studies of the cellular defense of the mammary gland.

Animals↗
PubMed1977

Response of plasma corticosteroids and circulating leukocytes in cattle following intravenous injection of different doses of adrenocorticotropin.

The relationships among exogenous adrenocorticotropin (ACTH), plasma corticosteroids, and circulating leukocytes were studied in 7 lactating cows. Blood samples were obtained from jugular cannulas at -2, -1, and 0 hours before ACTH was injected (base line) and 0.25, 0.50, 1, 2, 3, 6, and 24 hours after injection. Plasma corticosteroids were increased progressively by injecting doses of ACTH between 1 and 200 IU. Plasma corticosteroids reached peak concentrations between 15 and 30 minutes and returned to base line within 1 to 3 hours after 1, 5, and 10 IU doses of ACTH were injected, but required as long as 6 hours after injection of 100 and 200 IU. Base line counts of circulating leukocytes averaged 7.3 X 10(3) cells/mm3 and remained unchanged after injecting 0 and 1 IU of ACTH (P less than 0.05). Significant dose-dependent increases in circulating leukocytes were detected within 2 hours after administering 5, 10, and 100 IU of ACTH. Responses to 100 and 200 IU were similar. The average concentration of leukocytes increased up to 6 hours after ACTH administration and returned to base line values within 12 to 24 hours in cows injected with 5 and 10 IU, but not until 48 hours in cows injected with 100 and 200 IU of ACTH. In contrast to the delayed and sustained responses observed for leukocytes, corticosteroid responses were rapid and transient. Moreover, the administration of 200 IU of ACTH was considered to increase circulating corticosteroids and leukocytes beyond that found in dairy cattle exposed to stress associated with overmilking, acute coliform mastitis, or parturition.

Adrenal Cortex Hormones↗
PubMed1976

Effect of bovine neutrophil maturity on phagocytosis.

The ability of immature circulating neutrophils to phagocytose foreign particles was determined. One quarter of each of 4 cows, which were free of mastitis and pathogens and had milk somatic cell counts of less than 1 X 10(6) cells/ml, was infused with endotoxin of Escherichia coli (0.5 mg in 3 ml of saline solution) to induce a milk leukocytosis and a shift to the left in circulating leukocytes. Milk samples were taken from the infused and one uninfused quarter before and after infusion. Blood samples were collected at 9 hours after infusion, at 2-hour intervals from 13 to 21 hours, and at 36 hours after infusion. Phagocytosis was determined by incubating whole blood with yeast cells and determining the precentage of neutrophils phagocytosing and the number of yeast cells per neutrophil. Milk somatic cells increased from an average of less than 1.0 X 10(6) cells/ml before infusion to 37.0 X 10(6) cells/ml at the next milking (postinfusion hour 11). Circulating immature neutrophils increased from 7.6% before infusion to 56.6% at postinfusion hour 21. The percentage of neutrophils phagocytosing was 99 to 100 throughout the study. Number of yeast cells per neutrophil (mean phagocytosis) decreased from 6.5 before infusion was done to 5.2 after infusion. However, there was no correlation between percentage of immature neutrophils and mean phagocytosis. The decrease in yeast cells per neutrophil was attributed to the decrease in concentration of neutrophils and yeast cells in the in vitro procedure (r = 0.50). Apparently the immature neutrophils that appear after depletion of the mature form are as phagocytic as the mature neutrophils.

Animals↗
PubMed1976

Effects of parturition and lactation on blood and milk cell concentrations, corticosteroids, and neutrophil phagocytosis in the cow.

Blood differential leukocytes, erythrocytes, milk somatic cells, and neutrophil phagocytosis in 14 Holstein-Friesian cows were measured at 2-day intervals for 2 weeks before parturition, on the day of parturition, on postpartum days 1,2,5,10,15, and 30, and at monthly intervals throughout lactation. Circulating corticosteroids were measured in 6 cows on days -6, -4, -2, on the day of parturition, and on days +1, +2, +5, +10, +15, +30, and +60. Circulating neutrophils on day -2 on the day of parturition, on days 2, 10, and 15 averaged 3,363, 5,889, 3,085, 4,116, and 3,558/mm, respectively. The increase in neutrophils at parturition was accompanined by an increase in corticosteroids (2.7, 9.0, 11.1, 6.1, and 5.4 ng/ml of blood plasma on days -4 and -2, on the day of parturition, and on days +1 and +2, respectively). The phagocytic ability of circulating neutrophils was determined by incubating yeast cells with whole blood (30 minutes, 37 C) and microscopically counting yeast cells per neutrophil. Mean yeast cells per neutrophil decreased (P less than 0.01) during the 2nd week after parturition (7.4, 6.5, 6.6, and 7.2 on days +2, +10, +15, and +30, respectively). But this decrease was compensated for by an increase in circulating neutrophils during the same period.

Adrenal Cortex Hormones↗
PubMed1975

Measurement of phagocytosis of 32P-labeled Staphylococcus aureus by bovine leukocytes: lysostaphin digestion and inhibitory effect of cream.

A procedure to measure phagocytosis by blood and milk neutrophils was developed. One milliliter of heat-killed 32P-labeled Staphylococcus aureus ([32P]SA) (180-200 X 10(6) CFU), 1 ml of phosphate-buffered saline solution (PBSS), and 2 ml of serum, whole milk, skimmed milk, whey, or PBSS were incubated in duplicate for 60 minutes at 37 C. Isolated blood or milk nuetrophils (polymorphonuclear leukocytes (PMN), 25 X 10(6) cells/ml; 1 ml) were added and incubated at 37 C for 30 minutes. Unphagocytosed [32P]SA organisms were lysed by incubation with 5 ml of lysostaphin (10 U) at 37 C for 30 minutes, and the PMN and phagocytosed T2P]SA were removed by centrifugation. Radioactivity of the supernatant was determined in a scintillation spectrometer and was used in estimate the percentage of [32P]SA phogocytosed. With this procedure, 25 assays in duplicate could be conducted each day with an expected coefficient of variation between duplicates of 5.6%. Blood PMN phagocytosed 80, 44, 74, 72, and 11% of the [32P]SA when incubated in serum, whole milk, skimmed milk, whey, and PBSS, respectively. Mik PMN phagocytosed 78, 44, 72, 74, and 22%, respectively. The addition of cream to either skimmed milk or serum reduced phagocytosis of [32P]SA by both blood and milk PMN. The inhibitory effect of cream was verified by the microscopic observation that PMN containing large quantities of ingested fat contained fewer S aureus. Seemingly, PMN upon entering the alveoli of the mammary gland become less efficiently phagocytic for bacteria, because of the presence of milk fat globules. This phef intramammary infection by invading mastitic pathogens.

Animals↗
PubMed1975

Effects of estrus and exogenous estrogen on circulating neutrophils and milk somatic cell concentration, neutrophil phagocytosis, and occurrence of clinical mastitis in cows.

In a study involving 56 quarters (14 cows), it was seen that standing estrus did not affect circulating neutrophil and milk somatic cell concentrations, neutrophil phagocytosis, milk production, or occurrence of clinical mastitis. The subcutaneous injection of 17beta-estradiol (E2) (0.05 mg/kg of body weight 2 times daily for 2 consecutive days) did not affect neutrophil phagocytosis or milk somatic cell values. However, a significant increase in circulating neutrophils and a significant decrease in milk production were observed. The injection of E2 was followed by clinical mastitis in 4 uninfected quarters, in 7 quarters infected with Corynebacterium bovis, and in 1 quarter infected with Streptococcus uberis and Escherichia coli.

Animals↗
PubMedDate not supplied

Production and preparation of hyperimmune bovine colostrum for passive immunotherapy of cryptosporidiosis.

Pregnant cows were immunized to produce hyperimmune bovine colostrum (HBC) by intramuscular injection or intramammary infusion (TI) followed by 3 successive TI boosters with Cryptosporidium parvum (Cp) oocyst antigen mixed with Freund's (F) or Ribi (R) adjuvant. Control cows received no Cp. Colostrum from all cows was skimmed of butterfat and tested for specific anti-Cp immunoglobulin isotypes by ELISA. The HBC from Cp-F and Cp-R immunized cows had IgG1 titers exceeding 1:400,000 and 1:800,000, respectively. Some HBC from Cp-F immunized cows was freeze-dried to facilitate storage and some were irradiated at 42.5 kGy to kill potentially contaminating pathogens. Freeze-drying, but not irradiation, reduced IgG1 titers by only one dilution. Neither treatment affected Western blot banding patterns.

Animals↗