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Biomedical subjects

L H Lauerman

Publications and source records attributed to L H Lauerman.

At least 19 recordsLinked to original sources
PubMed1991

Chemically induced viral resistance in single preimplantation bovine embryos.

Viral mRNA encoding vesicular stomatitis virus glycoprotein sequences was detected and quantitated using a DNA-hybridization dot-blot technique. This assay was employed to determine if the synthetic double-stranded polynucleotide complex of polyriboinosinic-polyribocytidylic acid would elicit viral resistance in vitro in single day 9 bovine embryos. The levels of viral mRNA were assayed in 4 groups of bovine embryos: unexposed, virus-exposed, polynucleotide-treated, and virus plus polynucleotide treated. Reduced quantities of viral mRNA in single polynucleotide treated embryos demonstrated that resistance to viral infection was induced in day 9 bovine embryos.

Animals↗
PubMed1990

Monoclonal antibody in the identification of Haemophilus somnus.

Electrophoretic comparisons of outer membrane proteins of Haemophilus somnus isolates revealed 2 major protein bands (46 and 14 kilodaltons [kD]) common to all isolates tested. A monoclonal antibody raised against H. somnus reacted to the 46-kD band. Coagglutination tests were performed using a monoclonal antibody coagglutination assay. The monoclonal reagent was produced by incubating Cowan strain Staphylococcus aureus suspension, used as a source of crude protein A, with mouse ascitic fluid monoclonal antibody or goat anti-H. somnus hyperimmune serum. Bacteria to be tested were suspended at a concentration of 4.5 x 10(9) cells/ml. The coagglutination test was performed by the addition of 50 microliters of the monoclonal reagent to 50 microliters of the bacterial suspension on a glass plate and manual rotation for 2-3 minutes. The coagglutination assay using Cowan strain Staphylococcus aureus protein A, coupled with the monoclonal antibody, agglutinated 10 different H. somnus isolates. The antibody reagent did not coagglutinate with Actinobacillus suis, A. equuli, Pasteurella haemolytica, P. multocida, or P. pneumotropica under similar test conditions.

Agglutination Tests↗
PubMed1989

Trypsin treatment of bovine ova after in vitro exposure to vesicular stomatitis virus.

Preimplantation bovine ova were exposed in vitro to vesicular stomatitis virus, Indiana serotype, to document adherence of the virus to the zona pellucida. To determine the efficacy of this treatment, some of the ova were treated with trypsin after exposure to the virus. Vesicular stomatitis virus was isolated from 5 of 10 groups of zona pellucida-intact ova after 12 sequential washes without trypsin treatment. Vesicular stomatitis virus was also isolated from 4 of 11 groups of zona pellucida-intact ova after trypsin treatment.

Adhesiveness↗
PubMed1988

Adherence of Haemophilus somnus to bovine embryos after in vitro exposure.

Preimplantation bovine embryos were exposed in vitro to Haemophilus somnus to determine whether the bacteria would adhere to zona pellucida-intact embryos or would adhere to or infect zona pellucida-free embryos. The effect of H somnus on in vitro embryonic development also was investigated. After exposure to H somnus and before washing, some of the zona pellucida-intact embryos were held in antibiotic-containing medium. Haemophilus somnus was isolated from 10 to 42 zona pellucida-intact embryos and none of the zona pellucida-free embryos. Haemophilus somnus was not recovered from any of the 32 antibiotic-treated embryos. The coculture system was not compatible with normal embryonic development, and all embryos had begun to degenerate by the end of the 18-hour exposure period.

Animals↗
PubMed1987

Monolayer culture of cells originating from a preimplantation bovine embryo.

The objective of this study was to establish a method by which trophectodermal cells originating from individual preimplantation bovine embryos could be perpetuated in monolayer culture. A single, Day-11 bovine embryo collected nonsurgically from a mixed-breed beef cow was cultured in Ham's F10 medium supplemented with fetal bovine serum, sodium pyruvate, insulin, and epidermal growth factor. After 13 d in culture the embryo had adhered to the surface of the plastic culture vessel and a monolayer covering 0.3 cm2 had developed in the manner of a tissue explant. The monolayer was successfully dispersed using trypsin-EDTA and the cells were passaged. Expansion to a 25-cm2 flask was achieved by the 4th passage. By passaging cultures at a dilution ratio of 1:2, cells were maintained for 38 passages before growth slowed. Transfers beyond the 44th passage were unsuccessful. The cell line, designated BE-13, was successfully frozen and thawed at the 9th, 12th, 15th, and 20th passages. The cell line contains both mono- and binucleate cells with a prominent rough endoplasmic reticulum characteristic of ruminant trophoblast cells. Susceptibility to eight bovine viruses was demonstrated. Such cell lines may provide inexpensive systems for the study of trophoblast metabolism and for investigation of the role of the trophoblast in the pathogenesis of selected bovine abortifacient diseases. Because of their range of viral susceptibility, these cells might also be useful for diagnostic purposes.

Animals↗
PubMed1986

In vitro exposure of preimplantation bovine embryos to vesicular stomatitis virus.

Vesicular stomatitis virus New Jersey serotype (VSV-NJ) adhered to 14 of 20 zonae pellucidae intact (ZP-I) bovine embryos exposed in vitro. The VSV-NJ-exposed ZP-I bovine embryos were washed by a single- or multiple-pipette procedure. The multiple-pipette washing procedure was more efficient in removing unattached virus than the single-pipette procedure, but neither washing procedure was effective in consistently removing attached virus from ZP-I embryos. The virus plaque assay with Vero-MARU cells was more sensitive than was the suckling mouse intracerebral inoculation procedure for detection of VSV-NJ from the sonic extracts of bovine embryos. A maximum of 15 infective VSV-NJ particles were detected adhering to one virus-exposed, washed ZP-I bovine embryo.

Animals↗
PubMed1986

Resistance of preimplantation bovine embryos to infection with Brucella abortus.

Preimplantation bovine embryos were exposed in vitro to Brucella abortus to determine if the bacteria would adhere to zona pellucida (ZP)-intact embryos or adhere to or infect ZP-free embryos. Brucella abortus was not isolated from ZP-intact or ZP-free groups of embryos after 10 sequential antibiotic-free washings. Brucella abortus was isolated from all groups containing ZP-defective embryos after the exposure period and washing. Detrimental effects on healthy in vitro development of embryos were not observed.

Animals↗
PubMed1985

Laboratory evaluation of aqueous humor in the healthy dog, cat, horse, and cow.

Using routinely available clinical laboratory methods, aqueous humor samples were evaluated from 12 healthy dogs, 15 healthy cats, 7 healthy horses, and 6 healthy cows. Aqueous humor was almost acellular; cells that were present had degenerated beyond recognition. Protein concentration was low; only albumin was detectable on electrophoresis. Creatine phosphokinase and lactate dehydrogenase isoenzymes were not detected. Artifacts induced by sampling were insignificant compared with alterations in aqueous humor composition that occur with ocular diseases.

Albumins↗
PubMed1982

Bluetongue virus in pregnant elk and their calves.

Two pregnant North American elk (Cervus canadensis), in the 3rd and 4th months of gestation, were inoculated with bluetongue (BT) virus (BTV) serotype 11. The virus was not isolated from the blood of the cows beyond postinoculation day (PID) 8, but was isolated from bone marrow and spleen samples obtained at necropsy on PID 190. Although neither cow had overt clinical signs of BT infection, fluctuations in specific neutralizing BTV antibody titers indicated viral replication. However, in 2 attempts, BTV was not recovered biologically via bites of colonized Culicoides variipennis (biting gnats) with subsequent transmission of the BTV to sheep. Bluetongue virus was isolated from the elk calves at birth and before they nursed. These calves remained latently infected, and BTV was transmitted from each calf to sheep by bites of the biting gnats. Most of the BTV biological recovery attempts resulted in suspicious BT clinical responses in sheep, but without viral isolation. However, after challenge exposure with the homologous virus, 5 of 7 recipient sheep bitten by the gnats reacted with an intensified BT clinical response that indicated viral sensitization. One calf was born weak, never attained a healthy appearance, was latently infected with BTV, and had fluctuating BTV neutralizing antibody titers. The other calf was in apparently good health, was latently infected with BTV, and was immunologically tolerant to BTV.

Animals↗
PubMed1979

Techniques for evaluating humoral and cell-mediated immunity in mule deer fawns (Odocoileus hemionus).

Twenty mule deer fawns (Odocoileus hemionus) were removed from their dams 48 h after birth, and hand-reared. Methods for monitoring their immune capability are described. Passive humoral immunity was determined by serum protein electrophoresis. Active humoral immunity following Clostridium toxoid vaccination was determined by immunodiffusion. Cell-mediated immunity was assayed using contact sensitization to 1-nitro, 2,4-dichlorobenzene (DNCB).

Animals↗
PubMed1979

Correlations between leukocidin production and virulence of two isolates of Fusobacterium necrophorum.

Leukocidin production by Fusobacterium necrophorum was suggested to be an important element in the development of intraabdominal and liver abscesses in mice. Leukocidin production by cultures of F necrophorum was demonstrated by an in vitro assay. One of two isolates of F necrophorum was demonstrated to produce leukocidin. The leukocidin-producing strain was observed to be more infective than the nonleukocidin-producing strain (as demonstrated by abscess formation following intraperitoneal injection of immune-suppressed and normal mice). The infectivity of the leukocidin-producing strain was increased by successive passage in immune-suppressed mice. A simultaneous increase in leukocidin production was also demonstrated. The nonleukocidin-producing strain could not be passed effectively and was relatively noninfective for mice.

Animals↗
PubMed1978

Biological and biochemical characteristics of Fusobacterium necrophorum leukocidin.

The production of a leukocidal exotoxin by 18-hour dialysis cultures of Fusobacterium necrophorum was detected in vitro by a cytotoxicity assay, using bovine leukocytes isolated from peripheral blood. Biological characteristics were determined while maximizing the in vitro assay. Biochemical characteristics of heat stability and stability to degradative enzymes were investigated and indicated that the leukocidin is protein in nature. The characteristics indicate that this leukocidin is different from previous descriptions in the literature of the characteristics of a leukotoxin produced by F necrophorum.

Biological Assay↗
PubMed1978

Metabolic and cellular profile testing in calves under feedlot conditions: protein fractions and lactate dehydrogenase isoenzymes--reference values.

Serum protein and lactate dehydrogenase (LDH) isoenzyme values were determined for frozen serum samples from crossbred yearling feedlot cattle on feed for 56 days. The mean percentage values for serum protein components from 114 samples were: albumin, 46.5; alpha-globulin, 10.4; beta-globulin, 18.7; gamma-globulin, 23.8. For LDH isoenzymes, they were: LDH1, 36.5; LDH2, 24.7; LDH3, 16.9; LDH4, 12.0; LDH5, 9.1. These values are compared with values from dairy cattle.

Animal Feed↗
PubMed1977

Immunoglobulin response to bluetongue virus soluble antigen in subcutaneous chambers.

Group-specific antibodies were produced by inoculation of bluetongue virus soluble antigen into polyethylene chambers implanted subcutaneously in 8 rabbits and 2 sheep. For comparison, 5 rabbits and 1 sheep were inoculated intramuscularly with the soluble antigen in Freund's complete adjuvant. Antibodies present in the serum and chamber fluids were detected by the agar gel precipitin or serum-neutralization tests, qualitatively examined by immunoelectrophoresis and immunofluorescence, and quantitated by electroimmunodiffusion.

Animals↗
PubMed1976

Characteristics of semen changes during Brucella ovis infection in rams.

The effect of brucellosis on semen quality in rams was studied by means of artificially infecting five rams with a strain of Brucella ovis isolated in Kenya. Infection resulted in reduced semen quality including reduced total sperm output, poor motility and a high percentage of morphological abnormalities. Variation in semen quality both between and within rams appeared to be related to progress of the disease in the epididymis as well as to the distribution and severity of lesions in the reproductive tract.

Animals↗