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J S Cullor

Publications and source records attributed to J S Cullor.

At least 55 records · Page 3Linked to original sources
PubMed1994

Bovine milk lymphocytes display the phenotype of memory T cells and are predominantly CD8+.

The phenotype of bovine milk lymphocytes was investigated and compared to peripheral blood lymphocytes using monoclonal antibodies specific for bovine leukocyte differentiation antigens and flow cytometry. T lymphocytes traffic selectively into bovine milk while B lymphocytes represent a minor population in milk by comparison to peripheral blood. The vast majority of T cells in milk express alpha beta T cell receptors and are predominantly CD8+. T cells in milk express twofold higher levels of CD2 and fivefold lower levels of CD45R, characteristics associated with memory T cells. Grouping of cows by lactational stage and analysis of lymphocyte subpopulation percentages indicated that CD4+ T cells are present in relatively low numbers in milk of cows in the first 50 days of lactation and have a significant tendency to increase in number as lactation progresses.

Animals↗
PubMed1994

In vitro antimicrobial activity of Shiva-11 against ocular pathogens.

Cecropins are antimicrobial peptides (30-35 amino acids) isolated from the hemolymph of the cecropia moth. Previous studies have demonstrated their antimicrobial efficacy against a variety of pathogens, including both gram-positive and -negative bacteria, fungi, protozoa, and enveloped viruses. To assess their therapeutic potential against ocular pathogens, we analyzed the in vitro antimicrobial activity of a synthetic cecropin analog, Shiva-11, against virulent microbial strains (Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans). Bacterial isolates were obtained from human cases of severe ulcerative keratitis. Shiva-11 was tested at varying concentrations in bacterial suspensions containing 1-2 x 10(6) CFU/ml at 37 degrees C. Samples were plated on nutrient agar and colonies counted after 24-48 h of incubation. Shiva-11 yielded > 3 log killing of all isolates after 60 min of exposure to this compound. The results of this study indicate that Shiva-11 possesses broad-spectrum in vitro antimicrobial activity against human clinical ocular pathogens.

Animals↗
PubMed1993

Purification, primary structures, and antibacterial activities of beta-defensins, a new family of antimicrobial peptides from bovine neutrophils.

A new family of cysteine-rich antimicrobial peptides from bovine neutrophils was isolated and characterized. Thirteen structurally homologous peptides were purified to homogeneity from a granule-rich cytoplasmic fraction of purified blood neutrophils. The complete sequences of the peptides were determined by a combination of enzymatic digestion, Edman degradation, and additional biochemical characterization of the carboxyl termini. The peptides are characterized by a highly cationic 38-42-residue chain which includes 6 invariantly spaced cysteines which form three disulfides. They share a highly conserved consensus sequence which is also found in a recently described epithelial antimicrobial peptide from bovine trachea. The in vitro antibacterial activities of the 13 neutrophil peptides, determined in assays using Staphylococcus aureus and Escherichia coli as test organisms, demonstrated that each peptide possessed antimicrobial activity, and that several were as active as the most potent neutrophil defensin, rabbit NP-1. Though the structural and functional attributes of the bovine neutrophil peptides are similar to those of defensins, the two peptide families are distinguished by their unique consensus sequences and additionally by differing tridisulfide motifs. We therefore propose that this new defensin-like antimicrobial peptide family be named beta-defensins.

Amino Acid Sequence↗
PubMed1993

Immunization and immunotherapy for mastitis.

Immunization and immunotherapy for mastitis are active areas of investigation. The past decade has seen development of effective and economical R-mutant vaccines for gram-negative mastitis. These vaccines doubtless will prove beneficial on well managed dairies that have eradicated contagious mastitis pathogens. Development of vaccines for other mastitis pathogens has been noticeably slower. A commercially available Staphylococcus aureus vaccine appears to reduce the frequency and severity of clinical episodes, but probably has minimal impact on the incidence or prevalence of infection. This product has not been extensively studied. The recent recognition of virulence factors produced in vivo by Staphylococcus aureus may provide a breakthrough in the development and production of Staphylococcus aureus vaccines. Bacterins employing this principle presently are not commercially available, however. In the case of all contagious mastitis pathogens (Streptococcus agalactiae, Staphylococcus aureus, and Mycoplasma spp.), traditional control and eradication efforts (teat dip, dry cow therapy, culling programs) likely will prove preferable to long-term immunization. Ongoing research may provide more efficacious vaccines for these mastitis syndromes. Immunostimulants are an active area of research. Although leukopoietic factors appear promising as immunostimulants, no compound has clearly demonstrated efficacy in either the prevention or treatment of bovine mastitis.

Animals↗
PubMed1993

Antibiotic residue tests for mammary gland secretions.

Current control methods are not effective in eliminating various mastitis pathogens, and antimicrobial therapy introduces some risk of contaminating dairy products with antibiotic residues. Individuals involved in animal agriculture are sensitive to their responsibility to prevent antibiotic residues from entering the food chain. The ability to understand and perform the appropriate screening systems for determining the residue status of an individual animal, bulk tank, or tanker truck sample provides an opportunity to practice residue management and enhance the quality of dairy products available to the consumer.

Animals↗
PubMed1993

Evaluation of milk antibiotic residue screening tests in cattle with naturally occurring clinical mastitis.

Milk from 172 commercial cows with mild to moderate clinical mastitis was tested with five antibiotic residue detection assay systems. One hundred cows were treated with one of two intramammary beta-lactam antibiotics, and the remaining 72 cows were treated with intramuscular oxytocin. Milk samples were collected pretreatment, twice after therapy, and again 21 d following the initiation of treatment. Presumptive false-positive assay results were tabulated from all pretreatment and 21-d milk samples and from samples collected following oxytocin therapy. The percentage of false-positive results was 43.6, 37.7, 81.7, 2.6, and 18.8% for the CITE probe (beta-lactam), Delvotest-P, Charm Farm, LacTek (beta-lactam), and Bacillus stearothermophilus var. calidolactis disk assay, respectively. In four of the assay systems, average SCC were significantly higher in samples yielding false-positive results than in those with negative results. Specificity and sensitivity were estimated for each assay system, and, based on these estimates, positive and negative predictive value curves were graphed as the prevalence of milk samples containing detectable concentrations of exogenous antibiotic residues in the sample population was varied from 0 to 100%.

Animals↗
PubMed1993

Efficacy of intramammary antibiotic therapy for treatment of clinical mastitis caused by environmental pathogens.

For three California dairy herds with bulk tank SCC < 200,000/ml, twice daily milking, and no mastitis vaccine, 254 quarters with mild clinical mastitis were randomly assigned to three groups. Group A (n = 74) was treated with 62.5 mg of intramammary amoxicillin every 12 h for three milkings. Group C (n = 75) was treated with 200 mg of intramammary cephapirin every 12 h for two milkings. Group O (n = 105) was treated with 100 units of intramuscular oxytocin every 12 h for two or three milkings. Aseptic pretreatment quarter samples revealed 94 (37%) coliforms, 65 (26%) environmental streptococci, 34 (13%) other bacteria, and 61 (24%) with no isolate on bovine blood agar plates. Contagious pathogens were not isolated. Clinical cure (return of quarter and milk to normal) and bacterial cure (absence of primary pathogen isolated pretreatment) were assessed at milking 8 and d 20 after initial treatment. No difference existed in clinical (67.6, 67.7, or 66.7%) or bacterial (43.9, 55.0 or 49.1%) cure rate among groups. Clinical cure rates did not differ when quarters were grouped by etiology, but clinical cure rates for quarters with pathogens other than streptococci or coliforms were lower in group O.

Amoxicillin↗
PubMed1992

Milk antimicrobial drug residue assay results in cattle with experimental, endotoxin-induced mastitis.

Antimicrobial drug residue testing was performed on milk samples obtained from 8 cows with experimental endotoxin-induced mastitis, using 4 commercially available assay kits. Although none of the cows in the study received antimicrobials, only 1 of the 4 assay procedures, assay C, had consistently negative results (specificity = 1.00). The proportion of positive assay results varied from 0 to 1.00 among combinations of sampling time, sample status (endotoxin-infused quarter vs composite noninfused sample). The proportion of positive results found when assay C was used (0) differed significantly from the proportion found when the 3 other assays were used. The proportion of positive results did not differ significantly between assay A (0.45) and assay B (0.48); however, both assays had a significantly lower proportion of positive assays than did assay D (0.86). Logistic regression models were developed predicting positive milk antimicrobial drug residue assay results as a function of assay kit, sample status, and time interval following experimental challenge exposure. Using assay A as a baseline risk, assay B and assay D were more likely to have positive assay results, and assay C had a decreased risk of positive assay results. Milk samples from endotoxin-infused quarters were at increased risk for positive assay results, compared with noninfused composite samples. Samples collected from endotoxin-infused quarters or control quarters were at increased risk for positive assay results following the intramammary infusion of endotoxin. Our findings suggest that specificity of milk antimicrobial drug residue assays varies greatly among assay kits and that intramammary inflammation may increase the proportion of false-positive assay results.

Animals↗
PubMed1992

Indolicidin, a novel bactericidal tridecapeptide amide from neutrophils.

A potent and structurally novel antimicrobial peptide was purified from the cytoplasmic granules of bovine neutrophils. Suspensions of Staphylococcus aureus and Escherichia coli were virtually sterilized by the peptide at a concentration of 10 micrograms/ml. The peptide was found to be comprised of 13 amino acids, 5 of which were tryptophan residues, and the carboxyl-terminal arginine was carboxamidated. The primary structure of the peptide, which we have named indolicidin, is H-Ile-Leu-Pro-Trp-Lys-Trp-Pro-Trp-Trp-Pro-Trp-Arg-Arg-NH2. The mole percent of tryptophan in indolicidin is the highest observed among known protein sequences. The multiple tryptophan residues presumably play an important role in the function of this unique antibiotic peptide.

Amino Acid Sequence↗
PubMed1992

eNAP-2, a novel cysteine-rich bactericidal peptide from equine leukocytes.

We purified a novel cysteine-rich antibiotic peptide, eNAP-2 (M(r), approximately 6,500), from acid extracts of equine neutrophils by sequential gel filtration and reversed-phase high-performance liquid chromatography and determined its partial N-terminal amino acid sequence. Although its cysteine motif distinguished eNAP-2 from all other currently known endogenous antibiotic peptides, including defensins and granulins, it showed substantial sequence similarity to WDNM1, a putative member of the four-disulfide-core protein family that also includes animal and human antiproteases, snake venom neurotoxins, and rat and mouse whey proteins. The antibacterial properties of eNAP-2 were tested against several equine uterine pathogens, namely, Streptococcus zooepidemicus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Killing of S. zooepidemicus was very efficient, as evidenced by a 94% decrease in numbers of CFU per milliliter after exposure to 100 micrograms of eNAP-2 per ml (approximately 15 microM) for 2 h. Exposure of E. coli and P. aeruginosa to 200 micrograms of eNAP-2 per ml for 2 h resulted in 90.2 and 77.6% reduction, respectively, in the numbers of CFU per milliliter. Bacteriostasis, without bactericidal activity, occurred after K. pneumoniae was incubated with 200 micrograms of eNAP-2 per ml. Additional studies will be required in other species and cell types to determine whether eNAP-2 is restricted to equine neutrophils or is the index member of a larger family of endogenous antibiotics.

Amino Acid Sequence↗
PubMed1992

Identification of eNAP-1, an antimicrobial peptide from equine neutrophils.

Endogenous, cysteine-rich antimicrobial peptides known as defensins are prominent components of human, rabbit, and rat neutrophils, yet little is known about their occurrence in other mammalian species. Although we did not detect mature (i.e., processed) defensins in equine neutrophil granules, we found that these granules contained small amounts of other cysteine-rich peptides with antimicrobial activity. One of these, eNAP-1, was purified by a combination of gel permeation and reversed-phase high-performance liquid chromatography from acid extracts prepared from the cytoplasmic granules of equine neutrophils. The molecular mass of eNAP-1 was approximately 7.2 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Amino acid analysis revealed that eNAP-1 had an unusually high cysteine content and that it was relatively enriched in alanine, glycine, lysine, and proline residues. The partial (N-terminal) amino acid sequence of eNAP-1 was DVQCGEGHFCHDXQTCCRASQGGXACCPYSQGVCCADQRHCCPVGF. Thirty-six of these residues (78.3%) were identical to those of a recently cloned human neutrophil peptide of unknown function and belonging to the granulin family. Homologous peptides have also been noted in rat bone marrow cells and rat kidney epithelins. We tested the ability of eNAP-1 to kill several equine uterine pathogens. Streptococcus zooepidemicus was killed most effectively, sustaining a greater than 99.8% decrease in CFU per milliliter after a 2-h exposure to 100 micrograms of eNAP-1 per ml (approximately 15 microM). Escherichia coli and Pseudomonas aeruginosa were somewhat less susceptible, manifesting 87.0 and 87.1% mean decreases in CFU per milliliter, respectively, after incubation for 2 h with 200 micrograms of eNAP-1 per ml. Klebsiella pneumoniae numbers were not significantly reduced after exposure to eNAP-1. These antimicrobial properties suggest that eNAP-1 may contribute to phagocyte-mediated host defense against equine infections.

Amino Acid Sequence↗
PubMed1992

Hematologic and bone marrow changes after short- and long-term administration of two recombinant bovine granulocyte colony-stimulating factors.

Colony-stimulating factors are a category of glycoproteins that are instrumental in the regulation of hematopoiesis and inflammation. This investigation documented the clinical bone marrow and peripheral blood responses to short-term and long-term administration of a recombinant bovine granulocyte colony-stimulating factor (rb-GCSF) and an analog, where the cysteine at position 17 was substituted with a serine (rb-GCSF ser17). The colony-stimulating factors produced the expected changes in the hematologic findings of the bovine subjects in the study, and there was a cell-specific response to the compounds. The sustained neutrophilia in the long-term study indicates that the bovine species can tolerate the administration of recombinant forms of bovine GCSF for extended periods of time without detectable adverse side effects. The neutrophils from the short-term study revealed no apparent fluctuation, either as enhanced or reduced capability to reduce nitro blue tetrazolium as compared to pretreatment neutrophils. The administration of both recombinant forms of GCSF produced large increases in the bone marrow myeloid:erythroid (M:E) ratio concomitantly with the neutrophilias. This is the first preliminary report documenting the bone marrow response of cattle to the native and recombinant (rb-GCSF ser17) forms of bovine GCSF.

Animals↗
PubMed1991

Preliminary field evidence for the association of clinical mastitis with altered interestrus intervals in dairy cattle.

Clinical mastitis and reproductive records from two southern California dairy herds were used in a cross-sectional study to determine the risk of an altered interestrus interval following clinical mastitis. An altered interestrus interval was defined as cycles occurring at either less than 18 day or more than 24-day intervals. The data were stratified by herd to assess herd differences and by lactation number to assess confounding by cow parity. The predominant pathogen isolated from mastitis cases in Herd 1 was Staphylococcus aureus , whereas the predominant pathogens in Herd 2 were gram-negative isolates. Cows in Herd 1 which had coliforms cultured from mastitic milk were excluded in the analysis for comparison with Herd 2. In Herd 1, cows with clinical mastitis were less likely to have an altered interestrus interval (Relative Risk [RR]=0.9; 95% Confidence Interval [CI]=0.6,1.6) than herdmates without clinical mastitis. However, cows in Herd 2 were almost two times more likely to have an altered interestrus interval following an episode of clinical mastitis compared to herdmates without clinical mastitis (RR=1.6; 95% CI=1.3,2.0). Because herd management practices differ and could cause differences in mastitis and reproductive outcomes at the dairies, this preliminary field evidence should be followed by prospective studies of luteal function after clinical coliform mastitis.

Journal Article↗
PubMed1991

Bactericidal potency and mechanistic specificity of neutrophil defensins against bovine mastitis pathogens.

Two neutrophil defensins, rabbit peptides NP-1 and NP-5, were examined for their in vitro antibacterial activity against a panel of Gram-positive and Gram-negative organisms isolated from mastitic cows. Incubation for 60 minutes with 5 micrograms/ml of NP-1 in 10 mM sodium phosphate buffer resulted in substantial killing (greater than 95%) of all organisms tested. Although NP-5 was virtually inactive under these same conditions, supplementation of the incubation mixture with dilute nutrient media sensitized otherwise resistant organisms to this defensin. For both NP-1 and NP-5, bactericidal activity was dependent on time and concentration. Our findings demonstrate that the spectrum of defensin bactericidal activities include clinically important bovine pathogens. Further, the data demonstrate that NP-1 and NP-5, peptides which are homologous in 18 of their 33 residue positions, possess distinct mechanisms of action.

Amino Acid Sequence↗
PubMed1991

The combined use of lipoxygenase and cyclooxygenase inhibitors in Klebsiella pneumoniae-induced bovine mastitis.

The effect of combined administration of flunixin meglumine (FM) and nordihydroguaiaretic acid (NDGA) on milk prostaglandin F2 alpha (PGF2 alpha) and leukotriene B4 (LTB4) concentrations, and inflammatory indicators of bovine mastitis was examined. Mastitis was induced in six Holstein cows by the inoculation of Klebsiella pneumoniae via the teat canal. Four cows were intravenously treated with FM (1.1 mg/kg) and NDGA (10 mg/kg) 1 hour prior to bacterial inoculation and again at post inoculation hour (PIH) 11. Two control cows were intravenously treated with equivalent volume doses of sterile isotonic saline solution at the same post inoculation time points. Combined use of FM and NDGA was effective in reducing elevations in milk PGF2 alpha levels and slightly effective in reducing elevations in milk LTB4 levels in the mastitic cows. Elevations in milk bovine serum albumin (BSA) levels were partially reduced during the early post inoculation time period in the FM and NDGA treated cows as compared to the saline treated control cows. Milk somatic cell counts from inoculated quarters were not significantly altered by FM and NDGA treatment. Elevations in rectal temperature were not reduced by FM and NDGA treatment, but clinical signs of quarter inflammation (warmth and swelling) were reduced by FM and NDGA treatment.

Animals↗
PubMed1991

Role of eicosanoids in abortion and its prevention by treatment with flunixin meglumine in cows during the first trimester of pregnancy.

Intravenous infusion of E. coli endotoxin at a rate of 4.16 ng/kg/min over 6 hr (total dose 1.5 micrograms/kg) in 5 cows in the first trimester of gestation induced abortion between 60 and 72 hr in three cows. Plasma PGF2 alpha levels in the aborting cows increased significantly to 289% of the zero time control (ZTC) at 1 hr and remained elevated for 9 hr. The PGF2 alpha level remained unaffected in the non-aborting cows except at 2 hr. The plasma TxB2 levels were increased by 6 to 18 fold for 6 hr in both the aborting and non-aborting cows relative to their ZTC controls. The 6-keto-PGF1 alpha levels were significantly increased to 2 to 3 fold only in the aborting cows. Plasma cortisol levels were increased maximally to 1,500% of ZTC at 5 hr in the aborting cows. Thereafter, the levels gradually declined but remained significantly elevated for 24 hr. The increases in the cortisol levels in the non-aborting cows were only 280% of ZTC at 5 hr and returned to ZTC value by 12 hr. Plasma progesterone levels in the aborting cows remained unaffected until 12 hr followed by a progressive decline through 18 hr to extremely low levels at 3, 4, and 5 days. Endotoxin-infusion caused hyperglycemia in both aborting and non-aborting cows and lactic acidemia in the aborting cows. Treatment with two doses of flunixin meglumine (FM, 1.1 mg/kg), an inhibitor of cyclooxygenase, 1 hr prior to endotoxin infusion and then 13 hr later, completely prevented the endotoxin-induced abortion and increases in the plasma PGF2 alpha, TxB2 and 6-keto-PGF1 alpha concentrations. The PGE level remained unaffected. Although FM treatment failed to abolish endotoxin-induced increases in the plasma cortisol and lactic acid levels, it effectively prevented marked decreases in the progesterone and increases in the glucose concentrations. It was concluded that the use of FM offers therapeutic promise in preventing bovine abortion caused by endotoxin resulting from bacterial infection during the 1st trimester of gestation.

Abortion, Veterinary↗
PubMed1991

Intracellular and extracellular enzymatic deacylation of bacterial endotoxin during localized inflammation induced by Escherichia coli.

Acyloxyacyl hydrolase (AOAH), an enzyme that removes the secondary acyl chains of gram-negative bacterial lipid A (endotoxin), has been identified previously in human neutrophils and mouse macrophages. We report here that bovine leukocytes also contain AOAH activity. Although bovine AOAH deacylates bacterial lipopolysaccharide in a manner similar to human AOAH, it is active in vitro over a broader pH range, from 4.0 to 7.0. By using Escherichia coli infection of the bovine mammary gland as a model of localized gram-negative bacterial disease and associated tissue inflammation, AOAH activity per leukocyte increased. In addition, AOAH activity increased in the cell-free portion of infected mammary secretions. These data indicate that AOAH activity increases in leukocytes associated with inflammation induced by gram-negative bacteria and provide additional evidence of its potential involvement in the defense against the effects of bacterial endotoxin.

Animals↗