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Biomedical subjects

D H Lein

Publications and source records attributed to D H Lein.

At least 37 records · Page 2Linked to original sources
PubMed1994

Hybridization of clinical Escherichia coli isolates from calves and piglets in New York State with gene probes for enterotoxins (STaP, STb, LT), Shiga-like toxins (SLT-1, SLT-II) and adhesion factors (K88, K99, F41, 987P).

Six hundred and sixty-six bovine and fifty-seven swine clinical isolates of E. coli from New York state were examined for the presence of enterotoxins (STaP, STb, LT, SLT-I, and SLT-II) and adhesins (K88, K99, F41, and 987P) using colony hybridization techniques. Three hundred and sixty-seven of the bovine isolates (45.2%) hybridized with at least one gene probe. Of these, two hundred and twenty-three (33.2%) hybridized with F41, one hundred twelve (16.7%) with K99, eighty-two (12.2%) with 987P, ninety-six (14.3%) with STaP, seven (1.1%) with STb, and none (0.0%) with LT and K88. A total of thirty-three (4.7%) of the isolates hybridized with SLT-I, and one (0.1%) with SLT-II. The major pathotypes among the 666 isolates from bovine were K99/F41/StaP (9.8%), K99/F41 (2.5%), p87P/F41 (2.1%) and 987P/K99/F41/StaP (1.4%). Of the swine clinical isolates, twenty-two hybridized with at least one gene probe. The major pathotypes among the isolates from piglets were K88/K99/F41/StaP (5.3%) and K88/F41 (5.3%).

Adhesins, Escherichia coli↗
PubMed1993

Expression and secretion of outer surface protein (OSP-A) of Borrelia burgdorferi from Escherichia coli.

Outer surface protein A (OspA) is encoded by the ospA gene from Borrelia burgdorferi. This protein induces immunity against infection in mice. The cloning and expression of OspA in Escherichia coli have been previously described, but the secretion of OspA into culture media in E. coli has not yet been reported. In this report we demonstrate that a chimeric OspA protein was secreted into culture media by E. coli when it also harbors the hemolysin secretion genes hlyBD. The OspA fusion protein was also overexpressed from a T7 promoter and purified by immobilized metal ion chromatography. This was possible because the fusion protein contains six histidyl residues in its N-terminus.

Antigens, Surface↗
PubMed1993

Cross-reactivity between B. burgdorferi and other spirochetes affects specificity of serotests for detection of antibodies to the Lyme disease agent in dogs.

Western immunoblots, the kinetics-based enzyme-linked immunosorbent assay (KELA), and the microagglutination test were used to evaluate cross-reactivity among antibodies to serovars of Leptospira interrogans (leptospiral serovars), and B. burgdorferi from naturally infected dogs, and to Serpulina (Treponema) hyodysenteriae from vaccinated rabbits. Whole-cell lysates from Borrelia spp., leptospiral serovars, and Serpulina spp. were used for SDS-PAGE, western blots, and KELA. Crossreactivity occurred between the antibodies to B. burgdorferi and leptospiral serovars when tested on the heterologous antigens. Antibodies to leptospiral serovars tended to cross-react more strongly with antigens of B. burgdorferi spp. than did antibodies to B. burgdorferi when tested against antigens of leptospiral serovars. The antibodies against B. burgdorferi showed a lesser degree of cross-reactivity to the antigens of S. hyodysenteriae and S. innocens than they did to leptospiral serovars. We conclude that cross-reactivity occurs between B. burgdorferi and leptospiral serovars. Validation and interpretation of ELISA tests for detection of antibody activity to whole cell lysates of the Lyme agent must take this cross-reactivity into consideration. Conversely, dogs infected with the Lyme agent do not show significant cross-reactivity in the microagglutination test for antibody to the leptospiral serovars.

Agglutination Tests↗
PubMed1993

Molecular analysis of the Actinobacillus pleuropneumoniae RTX toxin-III gene cluster.

Actinobacillus pleuropneumonia strains that secrete three different exotoxins (ApxI, ApxII, and ApxIII) have been implicated in the etiology of porcine pleuropneumonia. To understand the role of these toxins in the pathogenesis of this disease, we have previously reported the cloning of the hemolysin gene (apxII) (Chang et al., 1989a), which encodes a 110-kD polypeptide with hemolytic and cytotoxic activity. To clone the third toxin gene (apxIII), a new genomic library using A. pleuropneumoniae serotype 2 chromosomal DNA was constructed. A series of five overlapping recombinant phage clones carrying the gene (apxIII) for this 120-kD antigen were identified using a DNA probe containing sequences from the Pasteurella haemolytica lktBD genes. Sequence analysis of a region of the cloned DNA reveals four open reading frames encoding proteins with predicted masses of 20.4, 112.5, 80.3, and 54.7 kD. These genes, designated apxIIC, apxIIIA, apxIIIB, and apxIIID, respectively, are similar in sequence to the RTX (repeat of toxin) toxin family. The toxin produced by the cloned gene kills BL-3 cells and is not hemolytic in vitro.

Actinobacillus pleuropneumoniae↗
PubMed1992

Comparison of spermatozoal movement and semen characteristics with fertility in stallions: 64 cases (1987-1988).

Information pertaining to evaluation of single ejaculates of semen and records for 2 consecutive breeding seasons were obtained. In all, data for 99 individual breeding seasons (n = 43 Standardbreds and 56 Thoroughbreds) were evaluated. Included in each semen evaluation was examination of semen characteristics and computer-aided analysis of spermatozoal movement characteristics. On the basis of the analysis of breeding records for 4,175 mares (7,017 estrous cycles), a per-estrous cycle fertility rate was calculated from data for 96 of the breeding seasons. Stallions with lower fertility than the mean overall season fertility had significantly (P less than 0.01) lower mean values for subjective appraisal of the percentage of motile and progressively motile spermatozoa and for percentage of morphologically normal spermatozoa. Lower mean values were obtained for computer-aided movement analysis of the percentage of motile and progressively motile spermatozoa, and for mean velocity of motile spermatozoa. Semen characteristics, including spermatozoal movement characteristics, and fertility were significantly (P less than 0.05) correlated for Thoroughbred and Standardbred stallions when analyzed individually and when data for both breeds were combined. Characteristics most highly correlated (P less than 0.01) with fertility data for both breeds combined were: subjective appraisal of the percentage of motile (r = 0.40) and progressively motile (r = 0.46) spermatozoa; percentage of morphologically normal spermatozoa (r = 0.36); and computer-aided analysis of percentage of motile spermatozoa (r = 0.34). However, on the basis of evaluation of a single ejaculate for each stallion, the variation in these characteristics only accounted for approximately 20% of the observed variation in fertility rate.

Animals↗
PubMed1992

Sequence analysis of the ROB-1 beta-lactamase gene from Actinobacillus pleuropneumoniae.

The ROB-1 beta-lactamase gene from Actinobacillus pleuropneumoniae was cloned and sequenced. The structural gene encodes a 305 amino acid polypeptide. The ROB-1 beta-lactamase gene sequence is identical to that derived from Pasteurella haemolytica and only one amino acid different from that of Haemophilus influenzae, suggesting that they are derived from the same ancestor, and transformed from one to another.

Actinobacillus pleuropneumoniae↗
PubMed1992

Characterization of plasmids with antimicrobial resistant genes in Pasteurella haemolytica A1.

Two R plasmids, pYFC1 and pYFC2, from Pasteurella haemolytica A1 encoding sulfonamide, streptomycin (pYFC1), and ampicillin (pYFC2) resistances have been characterized by restriction endonuclease digestions, subcloning or DNA sequencing. pYFC1 consists of 4225 bp and is 51.9% in AT content. Physical mapping indicated a highly conserved region of restriction sites among pYFC1, RSF1010, pGS05, pFM739, pHD148 and pGS03B. pYFC1 encoded a dihydropteroate synthase (29.8 kDa), and streptomycin kinase (29.6 kDa) which is homologous in nucleotide sequences or deduced amino acid sequence to that encoded by a broad-host range IncQ plasmid RSF1010. Based on the primary structure of pYFC1, the sulfonamide and streptomycin genes are derived from the same ancestor of RSF1010. pYFC2 is similar to the plasmid from P. haemolytica LNPB51 isolated in France by partial restriction enzyme mapping. pYFC1 and pYFC2 have the same size of 4.2 kbp.

Amino Acid Sequence↗
PubMed1991

The repeatability and effect of season on seminal characteristics and computer-aided sperm analysis in the stallion.

The within-stallion repeatability and effect of season on sperm movement characteristics, determined by computer-aided sperm analysis (CASA), were compared with those of other seminal characteristics. The computer-aided determinations of sperm movement were more repeatable than the seminal characteristics of gel-free volume and sperm cell concentration based on coefficients of variation obtained from the analysis of multiple ejaculates from the same stallions. A significant (P<0.05) seasonal effect on the computer-aided movement characteristic of mean sperm linearity was observed, with a reduction in sperm linearity in the winter months. The percentage of motile and progressively motile cells and mean sperm velocity determined by CASA also tended to be lower in the winter months. These changes in sperm movement characteristics paralleled changes in other seminal characteristics. The use of CASA may have value in the potential fertility evaluation of a stallion in that it can provide relatively precise quantification of sperm movement characteristics from the evaluation of only a few ejaculates. Some CASA derived sperm movement characteristics may be lower during the physiological nonbreeding season than during the breeding season.

Journal Article↗
PubMed1990

Determination of the relationship between sperm morphologic classifications and fertility in stallions: 66 cases (1987-1988).

The analysis of breeding records and sperm morphologic classifications from ejaculated semen during 99 stallion seasons, over a 2-year period, revealed a significant correlation (r = 0.34, P less than 0.01) between the percentage of morphologically normal sperm in ejaculates and the per cycle fertility estimate of the stallions studied. In addition, the percentage of sperm classified as having major defects (abnormal heads, proximal droplets, and abnormal midpieces) was significantly inversely correlated (r = -0.36, P less than 0.01) with the same fertility estimates. Multiple variable regression demonstrated that the variation in 2 morphologic features classified as major defects, abnormal heads, and proximal droplets, accounted for the largest amount of variation in fertility. It appears that in stallions, a large percentage of ejaculated sperm with major defects or other defects in combination with major defects is associated with a larger reduction in fertility than is associated with other defects.

Animals↗
PubMed1989

Comparison of effects of transcutaneous electrical nerve stimulation of auricular, somatic, and the combination of auricular and somatic acupuncture points on experimental pain threshold.

This study compared the effects of high intensity, low frequency transcutaneous electrical nerve stimulation of auricular, somatic, and combined auricular and somatic acupuncture points on experimental pain threshold measured at the wrist. Sixty-seven healthy adults, aged 18 to 39 years, were assigned randomly to one of four groups: 1) the Auricular Group (n = 17) received TENS to auricular acupuncture points, 2) the Somatic Group (n = 17) received TENS to somatic acupuncture points, 3) the Combined Group (n = 17) received TENS to both auricular and somatic acupuncture points, and 4) the Control Group (n = 16) received no TENS and served as controls. Pain threshold was measured immediately before and after treatment or rest. Pain threshold significantly increased (p less than .05) in the Auricular, Somatic, and Combined Groups following treatment, with no statistically significant differences in mean pain threshold change scores among treatment groups. The Control Group demonstrated no statistically significant change in pain threshold. The results indicate that TENS applied to any of the three sets of acupuncture points equally increases pain threshold, thus possibly increasing options in choosing stimulation sites for treating patients with pain.

Acupuncture Therapy↗
PubMed1989

Self-limiting reflex luteinizing hormone release and sexual behavior during extended periods of unrestricted copulatory activity in estrous domestic cats.

Estrous female cats (queens) were permitted 36-h periods of unrestricted mating activity; they then were injected with various doses of gonadotropin-releasing hormone (GnRH) at 36 h and allowed single copulations at 48 or 72 h of study. Serum luteinizing hormone (LH) levels were determined in samples collected prior to and 2 h after the initial copulation, before and 30 min after selected copulations during the next 10 h, and before and 30 min after copulations occurring at 20-24, 36, and 48-72 h, as well as 0, 15, and 30 min after the GnRH injections (0.3-3.0 micrograms/kg) at 36 h of study. Copulations occurred 14-20 times in 12 h and 20-36 times in 36 h. Copulation frequency (mean +/- SEM) decreased (p less than 0.05) from 5.5 +/- 0.6/2 h initially to 1.5 +/- 0.6/2 h during the subsequent 2-h period, and was 1.4 +/- 0.2/2 h at 12-36 h of study. Intromissions lasted 1-27 (8 +/- 0.3) s. Variation in durations of mounting by males (1.7 +/- 0.1 min; range, 0.3-10 min) or of the postcoital behavioral reactions displayed by the queens (2.5 +/- 0.1 min; range, 1-17 min) could not be related to animals or time of study. Peak serum LH levels (11-280 ng/ml; mean, 112 +/- 30 ng/ml) were observed at 2-4 h after the first mating. Mean LH steadily declined thereafter, reached basal values (less than or equal to 3 ng/ml) by 20-24 h, and remained low at 36 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Objective analysis of stallion sperm motility.

An image-analysis system utilizing a microcomputer and CellSoft computer-assisted semen analysis software package was evaluated to assess stallion sperm motility characteristics. Analyses were performed at 37 degrees C on a 6 microl drop of diluted semen placed on a glass slide and covered with an 18 mm(2) coverslip. Four groups of 25 cells each per slide, four slides per ejaculate and four ejaculates from each of three stallions were analyzed in a nested model. The percentage of motile sperm cells, mean velocity (microm/sec), mean linearity, and mean angular head displacement (microm) were measured. Statistical analysis of variance components showed that within ejaculates, more variation was accounted for in the differences among groups of 25 cells than among slides. Predicted standard deviations calculated for combinations of slides and groups of cells showed that a combination of two slides from which a total of 400 cells were analyzed resulted in a mean intra-assay coefficient of variation (CV) of 5.7% for the four measured variables. The following are individual coefficients of variation: percentage of motile cells (7.8%), mean velocity (6.4%), mean linearity (1.9%) and mean angular head displacement (6.6%). When ejaculate differences were included in the model and predicted standard deviations were calculated for a single ejaculate, the mean inter-assay CV was 9.2%. Mean velocity (6.4%) and mean linearity (4.7%) were more repeatable among ejaculates than either the percentage of motile sperm (14.4%) or angular head displacement (11.2%). It was concluded that this system is precise enough to determine differences in motility characteristics of stallion semen samples.

Journal Article↗
PubMed1988

A new antibiotic combination for frozen bovine semen 1. Control of mycoplasmas, ureaplasmas, Campylobacter fetus subsp. venerealis and Haemophilus somnus.

Systematic evaluations of new combinations of antibiotics for the control of bovine mycoplasmas, ureaplasmas, Campylobacter fetus subsp. venerealis and Haemophilus somnus in a bovine frozen semen process were made. These organisms were standardized to 10(5) to 10(6) colony forming unit (CFU) and inoculated into each ml of raw semen. Antibiotics in a final volume of 0.02 ml were added to each ml of the raw semen and were contained at the same concentration in the nonglycerol portion of the extenders (whole milk, 20% egg yolk citrate, 20% egg yolk tris, Plus-X, and 28% egg yolk tris). The combination of gentamicin (500 ug/ml) tylosin (100 ug/ml) and Linco-Spectin (300/600 ug/ml) was more effective for the control of mycoplasmas and ureaplasmas and equally effective for the control of C. fetus subsp. venerealis and Haemophilus somnus than the standard combination of penicillin, dihydrostreptomycin and polymyxin B sulfate.

Journal Article↗
PubMed1984

Transmissibility of the contagious equine metritis organism for the cat.

A group of SPF cats were moderately susceptible to the causal organism of contagious equine metritis (CEM) following intra-uterine or intrapreputial challenge with an Irish streptomycin resistant strain isolated from a clinically infected mare. Subclinical infections were established in only 50% of the cats, none of which became long-term carriers of the organism. Cytological examination of vaginal smears was of no diagnostic value in confirming infection in inapparently infected cats. Bacteriological responses after primary or secondary challenge with the CEM organism were essentially similar, with one exception, a female cat in which there was possible evidence of local immunity persisting after the primary infection. Efforts to reactivate shedding subsequent to the immediate post-challenge period were unsuccessful. Throughout the experimental period, the cats remained sero-negative to the complement-fixation test, and they failed to develop any significant increase in the levels of antibody activity as measured by the kinetics-based ELISA or KELA system. On day 89 after primary challenge, the cats were euthanized and various sites in the genitourinary tract and the internal iliac lymphatic glands subjected to bacteriological and pathological examination for evidence of CEM infection with negative results. The findings of this study, although establishing the transmissibility of the CEM organism for the cat, demonstrate the limited value of this species as an experimental model system for the disease in the horse.

Animals↗
PubMed1984

Canine inherited hypertrophic neuropathy: clinical and electrodiagnostic studies.

Clinical and electrodiagnostic features of acute and chronic canine-inherited hypertrophic neuropathy were studied in 20 affected dogs. The age of onset was consistently between 7.5 and 10 weeks of age. Affected pups had rapidly developing limb weakness accompanied by muscle hypotonia and hyporeflexia. There was no clinical evidence of cranial nerve dysfunction. Pups that did not develop limb contractures later regained some strength and became clinically stable for long periods, although they always remained weak. Progressive slowing of nerve conduction velocities occurred during the development of clinical signs of limb weakness. Temporal dispersion of evoked muscle action potentials was present in more chronically affected dogs. Transient spontaneous activity was present in muscles of affected dogs examined by electromyography. An autosomal recessive mode of inheritance was supported by the results of breeding studies.

Animals↗