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Biomedical subjects

R E Pearson

Publications and source records attributed to R E Pearson.

At least 109 records · Page 6Linked to original sources
PubMed1981

Comparison of single and multiple-trait selected sires. Response in mastitis traits.

Estimated somatic cell counts and incidence mastitis were measured on 163 daughters of two groups of bulls selected by two alternative criteria. Yield bulls were selected solely on progeny test for milk in first lactation; Merit bulls were selected by independent culling levels on fat-corrected milk yield, percent daughters culled in first lactation, and udder type conformation of daughters. Daughters of Yield sires exceeded daughters of Merit sires by 685 kg milk in first lactation. Groups did not differ significantly in measures of clinical mastitis or in measures of estimated cell counts of milk. Also, groups did not differ in kilograms milk discarded because of antibiotic treatment for mastitis, in spite of the large difference in total milk yield. Mean milk discarded per lactation completed was 171 kg, representing 64,243, and 207 g for parities one, two, and three.

Animals↗
PubMed1980

IgA, igG1, IgG2, IgM, and BSA in serum and mammary secretion throughout lactation.

Bovine IgG1, IgG2, IgA, and IgM were measured in the serum and lacteal secretions of six cows from 10 days prepartum to 240 days of lactation. Immunoglobulins in lacteal secretions were expressed in units of concentration (mg/ml) as well as in total daily output. All isotypes were selectively accumulated during colostrum formation. The rate of IgG1 accumulation decreased rapidly after calving; this decrease corresponded to a return to normal serum levels of this immunoglobulin. Selective accumulation of IgA > IgM > IgG1 was maintained throughout lactation, but IgG2 showed no selective accumulation beyond 5 days postpartum. In serum, IgA and IgM levels were elevated at parturition and showed a significant decrease postpartum. Increases in serum IgA levels 60 days postpartum corresponded to a rise in lacteal concentration. The concentration of all immunoglobulins increased during late lactation, coincident with a major reduction in milk yield. Six strains of mastitis-causing organisms were cultured during the period of the experiment; however, none resulted in clinical mastitis or showed an effect on immunoglobulin secretion.

Animals↗
PubMed1980

Shutoff of lambda gene expression by bacteriophage T4: role of the T4 alc gene.

Bacteriophage T4 normally contains 5-hydroxymethylcytosine instead of cytosine in its DNA. Multiple mutants of T4 which synthesize DNA with cytosine do not transcribe their late genes due to the action of the T4 alc gene (Snyder et al., Proc. Natl. Acad. Sci. U.S.A. 73:3098--3102, 1976), which is also responsible for unfolding the host nucleoid after T4 infection (Sirotkin et al., Nature [London] 265:28--32, 1977; Tigges et al., J. Virol. 24:775--785, 1977). It seems reasonable that T4 alc function plays a role in shutting off host transcription, and the observation that some of the RNA made after infection with a T4 alc mutant hybridizes to Escherichia coli DNA (Sirotkin et al., Nature [London] 265:28--32, 1977; Tigges et al., J. Virol. 24:775--785, 1977) supports this hypothesis. Although it is likely that the roles of the alc function in the blocking of some types of transcription and in the unfolding of the host nucleoid are related, it is not known how these effects are achieved or, in fact, whether all types of transcription are affected equally by the alc function. In an attempt to answer these questions, we studied the effect of T4 alc function on bacteriophage lambda transcription and on the structure of intracellular lambda DNA. We found that the alc function is responsible for the shutoff of lambda late transcription but probably not for the shutoff of lambda early transcription. We also found that alc does not block lambda transcription by directly removing the supercoils from circular lambda DNA via either a nicking or topoisomerase activity. Furthermore, we conclude that T4 infection also prevents the translation of non-T4 mRNA because late lambda mRNA's were made after superinfection by a T4 alcs mutant and were of normal length but were not translated into lambda late proteins.

5-Methylcytosine↗
PubMed1980

Stocking density effect on weight gain of yearling Holstein heifers in freestall and loose housing.

Stocking densities of replacement yearling Holstein heifers were studied under freestall conditions (1.0, .71, and .63 freestall/head) and loose housing conditions (4.5, 3.2, and 2.8 m2/head under roof) in two 180-day growth trials. Heifers gained .69, .69, and .66 kg/day under freestall conditions and .63, .56, and .71 kg/day under loose housing conditions for the stocking densities. Stocking densities of replacement herd heifers may be increased to .63 freestall/head under freestall conditions or to 2.8 m2/head under loose housing conditions without expanding existing facilities.

Animals↗
PubMed1980

Quarter milk variation in immunoglobulins and ability to support phagocytosis.

Milk samples were collected from two quarters in each of 8 cows that had Wisconsin Mastitis Test scores of less than 8.0. After letdown was stimulated, 35 ml of foremilk, the sixth 35 ml (middle milk), and 45 ml of strippings were collected by hand. Measured on each fraction were immunoglobulins, serum albumin, total protein, pH, percentage fat, Wisconsin Mastitis Test, and the ability of skim milk and whole milk to support phagocytosis of Staphylococcus aureus by isolated donor milk neutrophils. Foremilk and middle milk differed in immunoglobulin M (.014 to .018 mg/ml) and in the ability of whole milk to support phagocytosis (32 to 28% S. aureus phagocytosed). The following measures differed from middle milk to strippings: immunoglobulin A (.063 to .083 mg/ml); immunoglobulin G1 (.238 to .302 mg/ml); immunoglobulin M (.018 to .023 mg/ml); fat (3.9 to 7.4%); and Wisconsin Mastitis Test (5.0 to 9.2). Immunoglobulin G2, bovine serum albumin, total protein, pH, and the ability of skim milk and whole milk to support phagocytosis did not change. Although small differences may exist between foremilk and middle milk, foremilk gave reliable estimates.

Animals↗
PubMed1980

Performance of calves fed fermented mastitic milk, colostrum, and fresh whole milk.

Weight gains, milk intake, and health of calves fed fermented mastitic milk from cows treated and not treated with antibiotics were compared with those of calves fed fermented colostrum or fresh normal milk at two intakes. Calves fed fermented mastitic milk from cows treated with antibiotics, not treated with antibiotics, fermented colostrum (diluted 1:1 with water), and fresh normal milk gained .13, .14, .13, and .10 kg/day in trial 1 fed at 8% of body weight daily, and .09, .11, .18, and .13 dg/day in trial 2 fed at 10% of body weight daily from birth through 30 days of age. All calves were housed in individual pens during milk feeding. Feeding milk at 10% in trial 2 did not improve gains over those in trial 1. Incidence of health disorders and mastitis in first lactation of cows fed fermented mastitic milk as calves was not different from those of cows fed fresh normal milk or fermented colostrum. Fermented mastitic milk appears to be an economical and safe feed for rearing calves when calves are housed individually during milk feeding.

Animals↗
PubMed1980

Effect of local immunization of the mammary gland on phagocytosis and intracellular kill of Staphylococcus aureus by polymorphonuclear neutrophils.

Four cows in the latter part of their 2nd, 3rd, or 4th lactations were immunized by multiple intramammary infusions of heat-killed Staphylococcus aureus in 2 quarters. The direct bactericidal effects of milk whey from the immunized and control quarters, before and after immunization, and the ability of these whey to support phagocytosis and intracellular kill were determined by incubating live S aureus with polymorphonuclear neutrophils isolated from milk. Immunoglobulins (Ig) were determined by single radial immunodiffusion. One immunized and 1 control quarter in each cow were challenge exposed with live S aureus and the courses of the infections were determined for 2 weeks. There were significant cow differences in all Ig classes and in percentage of phagocytosis. Immunization resulted in a significant increase in IgA, IgG2, and IgM in the immunized quarters. Whey collected from immunized quarters supported phagocytosis of S aureus by isolated milk polymorphonuclear neutrophils significantly greater than did whey from control quarters. Extracellular live S aureus in the incubation medium was decreased by 59% in whey collected after immunization from immunized quarters. This decrease in extracellular S aureus was associated with a concomitant increase in total intracellular S aureus. However, intracellular live organisms showed no change. This lack of change indicated that the additional S aureus that were phagocytosed were killed. Direct bactericidal effects of whey were not observed. Intracellular live S aureus was not significantly correlated with any of the variables measured.

Agglutination Tests↗
PubMed1980

Effect of udder inflammation on milk immunoglobulins and phagocytosis.

Udder inflammation was induced in two quarters in each of eight cows by infusing oyster glycogen in saline solution. Milk was collected before and after infusion for immunoglobulin (Ig) and phagocytosis assays. Milk Ig and bovine serum albumin were measured by single radial immunodiffusion. The concentrations (mg/ml) of the immunoglobulins (IgA, IgG1, IgG2, and IgM) and bovine serum albumin before and after infusion were: IgA = 0.064 (before), 0.084 (after); IgG1 = 0.323, 0.486; IgG2 = 0.046, 0.094; IgM = 0.091, 0.124; and bovine serum albumin = 0.207, 0.451. The fact that IgA, IgG1, IgG2, and IgM were significantly correlated with bovine serum albumin within the cows before and after inflammation suggests a passive transfer of these Ig during inflammation. Phagocytosis was determined by incubating polymorphonuclear leukcotyes collected after infusion with 32P-tagged Staphylococcus aureus in autologous skim milk collected before and after infusion. The difference in percentage of phagocytosis before (42%) and after (36%) infusion was not significant. None of the Ig were significantly correlated with phagocytosis.

Animals↗
PubMed1980

Relationship among leukocyte phagocytosis, milk immunoglobulins, and susceptibility to intramammary infection.

A study was conducted to determine the variation among cows (n = 7 and among quarters within cows in the ability of milk to support phagocytosis, immunoglobulin (Ig) concentration, and the response to intramammary challenge exposure with live Staphylococcus aureus. Before challenge exposure, the average concentration (milligrams/milliliter) of each class of Ig was: IgA = 0.05, IgG1 = 0.42, IgG2 = 0.06, and IgM = 0.05. The percentage of phagocytosis of S aureus by milk neutrophils was significantly correlated with IgA (r = 0.59; P < 0.01), IgG1 (r = 0.52; P < 0.01), and agglutination titer (r = 0.68; P < 0.01). Agglutination titer was significantly correlated with IgA (r = 0.52; P < 0.01) and IgG1 (r = 0.63; P < 0.01). Bovine serum albumin was significantly correlated with IgA (r = 0.55; P < 0.01) and IgG2 (r = 0.49; P < 0.01). An IgG1/IgG2 ratio of 7.0 in milk, as compared with an IgG1/IgG2 ratio of 0.7 in serum, indicated a selective transport for IgG1. After challenge exposure, the IgG1/IgG2 ratio in infected and noninfected quarters was 12.9 and 16.0, respectively. The fact that neither the bovine serum albumin nor the direct microscopic somatic cell count in the noninfected quarters changed indicated that the increase in the IgG1/IgG2 ratio was due to an increase in selective transport in all quarters and not to a change in permeability due to a generalized inflammatory response. The correlation between the number of challenge exposures required to produce an infection was significantly correlated with percentage of phagocytosis (r = 0.70; P < 0.01).

Agglutination Tests↗
PubMed1979

Leukocytes--second line of defense against invading mastitis pathogens.

In mammals, neutrophile polymorphonuclear leukocytes constitute one of the essential body defenses against disease. In a large mammal, such as the dairy cow, billions of neutrophils are mobilized to fight infection. For example, over 50 million neutrophils per milliliter milk are commonly in a mammary quarter inflicted with clinical mastitis. However, in spite of these numerous leukocytes, pathogenic organisms remain viable. Recent evidence indicates that bacteria are not eliminated from a diseased quarter because the phagocytic capacity of the neutrophils is reduced in the mammary gland. The morphology and physiology of the leukocyte is examined in this review in an attempt to explain why the phagocytic capacity of the neutrophil is reduced in the mammary gland of the bovine.

Animals↗
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↗
PubMed1979

Three times a day milking during the first half of lactation.

Three milking frequency treatments were compared: twice daily milking; thrice daily milking until milk dropped below 24 kg; thrice daily milking until milk dropped below 31 kg. Three time milking was at least 45 days but no more than 150 days. Cows (12 to 14 per group) were managed alike except for milking frequency. In early lactation, increased milking had little effect. With time the superiority in yields increased such that cows on three times for 150 days were outproducing two time cows by 20%. Cumulative milk yields were greater for the thrice groups than for the twice group by 5% at 56 days, 11 and 8% at 154 days, 11 and 9% at 182 days, and 10% at 280 days. Fat percentage, adjusted for previous lactation fat percentage, averaged .2 to .3% lower for the cows milked three times until 24 kig but only .1% lower for cows milked thrice until 31 kg. Increased yield was primarily from prolonged peak yield and less subsequent decline. Switching from three to two milkings decreased yield 6 to 8% in the 1st wk. However, three time milking had a positive carryover, apparently due to higher starting yield at the point at which they were switched.

Animals↗
PubMed1978

Comparison between tail vein and jugular vein cannulation in cattle.

Blood samples obtained simultaneously from the jugular and tail (coccygeal) veins during induction of bovine mastitis infection and after administration of 250 IU of adrenocorticotropin did not differ in percentage of hematocrit, concentration of total corticosteroid in plasma, or concentrations of total circulating erythrocytes and leukocytes. Patency of the tail vein cannula was maintained for 1 mo. Tail vein cannulation is a practical alternative to jugular cannulation in cattle.

Animals↗
PubMed1978

Closed intramedullary shortening of the femur.

Closed intramedullary shortening of the femur in the adult provides a method for leg length equalization that poses minimal operative risks, maximizes healing, and produces an excellent functional and cosmetic result. The etiology of anisomelia and any associated abnormalities must be carefully analyzed preoperatively. A series of 40 closed intramedullary shortenings of the femur were performed; shortening averaged 3.3 cm (range 2.0 to 5.0 cm). Three patients had significant complications: delayed union in one patient required renailing; two cases of symptomatic external rotation deformity required correction. The technique for the procedure is demanding in terms of experience and equipment. Otherwise, intramedullary femoral shortening is an excellent method for managing adult anisomelia.

Adolescent↗
PubMed1978

Variation among cows in the ability of milk to support phagocytosis and in the ability of polymorphonuclear leukocytes to phagocytose Staphylococcus aureus.

Marked variation existed among cows in the ability of their milk to support phagocytosis and in the ability of polymorphonuclear leukocytes isolated from their milk to phagocytose Staphylococcus aureus. Furthermore, milk samples that supported a low degree of phagocytosis were generally obtained from cows that had a greater occurrence of clinical mastitis per lactation (r = 0.41). Results from this study suggest that variation in the phagocytic defense mechanism of the bovine mammary gland could contribute to the difference in susceptibility to infection by mastitis pathogens.

Animals↗
PubMed1977

Lithium in depression: a biochemical study.

Two groups of depressed subjects, one with a history of recurrent depression, the other with a history of persistent apathy, were given lithium carbonate 1,200 mg q.i.d. and supplementart potassium 1,200 mg t.d.s. for 1 week. Measurements were made before and after the lithium treatment of total body water (tritium space), extracellular fluid (sulphate space), total exchangeable sodium (Nae) and total exchangeable potassium (Ke) using sodium-24 and potassium-42 multiple isotope dilution techniques. Prior to treatment when compared with a group of normal subjects, both depressed groups showed changes in body fluid volumes and electrolyte levels. Total body water, intracellular fluid and intracellular potassium were lowered, while electrolyte levels. Total body water, intracellular fluid and intracellular potassium were lowered, while intracellular sodium was raised. After treatment with lithium the values in the apathetic group showed little change but the group with recurrent depression showed a significant increase in intracellular fluid (p less than 0.025), Ke (p less than 0.001), intracellular potassium (p less than 0.025) and a significant decrease in Nae (p less than 0.05). There was a marked increase in mood in the group with recurrent depression but not in the apathetic group following lithium treatment. These findings suggest that recurrent depression, both in clinical improvement, mood and also correction of water and also correction of water and electrolyte disturbances arise, but not in patients with long-standing apathy.

Aged↗