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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↗
PubMed1983

Cause and pathogenesis of middle ear infection in young feedlot cattle.

Two populations of feedlot cattle--weaned calves and yearlings--suffered otitis media. In calves the disease was acute and epizootic and had a prevalence of about 400 cases per 2000 cattle, whereas in yearlings, it was chronic and sporadic and had a prevalence of 1 case per 2000 cattle. Clinical signs were facial paralysis, otorrhea, and head tilt. The middle ears from 64 dead calves and 22 dead yearlings were examined. Calf ears had acute infection, with exudate in air cells and rupture of tympanic membranes. Yearling ears had chronic infection, with exudate in air cells, rupture or destruction of tympanic membranes, and necrosis of air cell partitions. Mixtures of Pasteurella multocida and Corynebacterium pseudotuberculosis were isolated from diseased ears, but Pasteurella multocida predominated in acute infections and Corynebacterium pseudotuberculosis predominated in chronic infections.

Acute Disease↗
PubMed1982

Effects of chloramphenicol on the development of immune responses to canine distemper virus in beagle pups.

The effect of oral chloramphenicol (CHPC) on the development of immune responses to canine distemper virus (CDV) in Beagle pups was studied. Dogs were treated with CHPC for 14 days at a dose of 50 mg/kg, three times a day. Hematologic changes in CHPC-treated dogs included: polychromasia, anisocytosis, and target cell formation of red blood cells concurrent with vacuolation of lymphocytes and basophilic granule formation in neutrophils. Dogs given this therapy showed normal in vivo and in vitro immune responses after CDV vaccination and survived a virulent CDV challenge, whereas untreated, unvaccinated dogs became ill or died after challenge exposure. The results of this study indicate that CHPC therapy does not interfere with either the prechallenge immune response to attenuated viral antigen or the efficient immune mechanisms invoked during virulent virus challenge.

Animals↗
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↗
PubMed1982

Purification and partial characterization of a macrophage cytotoxin from Pasteurella haemolytica.

A protein from Pasteurella haemolytica that was highly immunogenic and toxic toward bovine alveolar macrophages was partially purified. When isolated from culture supernatants of P haemolytica serotype 1 or serotype 6, the protein reacted on Ouchterlony immunodiffusion tests with antisera from 12 serotypes of P haemolytica, but did not cross-react with antisera to serotypes of P multocida. This indicated that the protein may be specific for P haemolytica. Bacteria were grown in dialysis culture in a brain-heart infusion and calf-serum growth medium. The protein was isolated from the medium by ultrafiltration and size-exclusion chromatography and has a molecular weight of approximately 150,000 daltons. The protein, which is highly immunogenic and has the characteristics of a virulence factor, is common to all serotypes of P haemolytica, and may be an effective agent for immunization against P haemolytica in cattle.

Antigens, Bacterial↗
PubMed1982

Metabolic and cellular profile testing in calves maintained under feedlot conditions: protein fractions and lactate dehydrogenase isoenzymes--changes over time.

Mean concentrations for total serum protein and serum protein fractions, and mean activities for total lactate dehydrogenase (LDH) and LDH isoenzymes were determined in 114 crossbred yearling cattle during a 56-day feeding trial. These values were to be used as predictors of performance (weight gain). The mean total serum protein concentration on day 0 was high (7.27 g/dl), reached a low on days 7 and 14 (6.47 and 6.50 g/dl), and then equilibrated toward the end of the study. The mean concentration for the albumin fraction also reached a low on days 7 and 14 (2.83 and 2.84 g/dl) and then increased, remaining steady until termination of the feeding trial. The alpha-, beta-, and gamma-globulin fractions fluctuated throughout the study. The mean for total LDH activity peaked on day 21 (1,363 IU) and then remained relatively constant through day 56. Mean serum activities for the LDH3 activity peaked on day 7 (27%) and then decreased progressively to day 56 (17%). The overall trend for LDH4 and LDH5 activities seemed to be a steady increase.

Animal Feed↗
PubMed1982

Ischemia: a cause of hepatic telangiectasis in cattle.

We histologically examined (i) 73 bovine livers condemned by packing house inspectors for telangiectasis, (ii) 15 bovine livers passed by the same inspectors as normal, and (iii) 8 livers from cattle given an injection into their mesenteric veins: 6 with a suspension of agar particles containing viable Haemophilus somnus and 2 with diluent only. The injected cattle were killed and necropsied 2 to 12 days after the inoculations. Of the 73 telangiectatic livers, 57 (78%) had thrombosed and occluded or contracted and empty portal veins (venopathies), whereas 1 of the 15 normal livers contained one microscopic focus of telangiectasis and nearby venopathy. Of the 6 livers injected with suspended particles, all had venopathies and telangiectasis and the 2 control livers had neither.

Animals↗
PubMed1981

Laryngeal diphtheria and papillomatosis in feedlot cattle.

In a random sample of 30,444 larynges from slaughtered beef cattle, 441 (1.4%) had chronic diphtheria and 1,345 (4.4%) had papillomatosis. Both types of lesions were centered in mucous membranes over the vocal processes and medial angles of the arytenoid cartilages. Since they are found in the same anatomical locations as laryngeal contact ulcers, we hypothesize that ulcers are primary and diphtheria and papillomatosis are secondary.

Animals↗
PubMed1981

Osteochondrosis in feedlot cattle.

Beginning in summer 1977 and continuing through four consecutive seasons, we examined lame limb joints from 106 partially fattened cattle and 28,235 pairs of occipital condyles from fully fattened cattle for osteochondrosis. Of the 106 lame cattle, nine (8.5%) had characteristic lesions, usually in their stifle joints, and of the 28,235 atlanto-occipital joints, 1063 (3.8%) had lesions on their condyles. Slices of affected articular cartilage and subjacent bone were studied radiographically and histologically. Radiographs showed subchondral defects and epiphyseal "cyst-like" lesions, and histologic sections showed disarrayed and degenerated chondrocytes. Splits occurred along osteochondral junctions or in adjacent cartilage or bone. Some bone trabeculae had been replaced by fibrous tissue that, in some areas, extended deep into epiphyses.

Animals↗
PubMed1981

Purification and biological characterizationof endotoxin fractions from Pasteruella haemolytica.

A sequential extraction procedure was used to provide 3 endotoxin fractions from Pasteurella haemolytica with distinct biological and solubility properties. After acetone dessication, extraction with phenol, chloroform, and petroleum ether (2:5:8) provided a fraction designated rough lipopolysaccharide (LPS). Subsequent extraction of the cells with 45% phenol at 68 C yielded a fraction designated smooth LPS, which was further divided into smooth precipitate and smooth supernatant, based on sedimentation at 105,000 x g for 4 hours. Yields of the 3 fractions were 1.5%, 3%, and 5.5% of the dry weight of the cells. The polysaccharide moieties of the rough LPS amd smooth precipitate fractions were obtained by partial acid hydrolysis followed by chloroform extraction. Biological activities of all 5 fractions were compared with activities of standard LPS fractions from Serratia marcescens and Salmonella typhimurium. Results of chicken embryo lethality, the local Shwartzman's phenomenon, nonspecific resistance enhancement ot challenge exposure by S typhimurium pyrogenicity, and the Limulus amebocyte lysate assay were reported.

Animals↗