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Biomedical subjects

R B Miller

Publications and source records attributed to R B Miller.

At least 73 records · Page 4Linked to original sources
PubMed1989

Protein A gold identification of ureaplasmas on the bovine zona pellucida.

The object of this study was to develop a prefixation protein A gold labelling technique for Ureaplasma diversum and to apply this to bovine embryos. Sixteen hour cultures of Ureaplasma diversum strain 2312 were incubated with either specific antiserum or nonimmune serum, followed by exposure to protein A gold and negative staining. The ureaplasmas which were incubated with specific antiserum were labelled with gold particles while those ureaplasmas which were incubated with nonimmune serum were not labelled. Twenty-three unhatched, day 7 bovine embryos were then incubated in either embryo culture medium (ECM) alone, ECM with sterile ureaplasma broth added or ECM with 1.7 X 10(6) colony forming units of Ureaplasma diversum strain 2312 per embryo. After 16 hours, the embryos were washed twice and incubated with either specific antiserum or nonimmune serum. The embryos were then incubated with medium containing protein A gold and examined by electron microscopy. No ureaplasmas were identified on the zona pellucida of the control embryos. Ureaplasmas were identified on the outer surface of the zona pellucida of 13 of the 17 embryos which had been exposed to the organism. Of these, the embryos which were incubated with specific antiserum had labelled ureaplasmas while the embryos which were incubated with nonimmune serum had unlabelled ureaplasmas on the zona pellucida. It was concluded that the protein A gold method was a suitable technique for the identification of ureaplasmas in EM preparations. The presence of ureaplasmas on the outer surface of the bovine zona pellucida following in vitro exposure to the organism was confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Reproductive performance of dairy cows following treatment with cloprostenol 26 and/or 40 days postpartum: a field trial.

One hundred and seventy Holstein Friesian cows were randomly assigned to receive either 500 ug cloprostenol or saline placebo on Day 26 postpartum followed by 500 ug cloprostenol or saline on Day 40 postpartum. Four treatment groups were formed: Group 1-saline (Day 26)/saline (Day 40); Group 2-cloprostenol/(Day 26) saline (Day 40); Group 3-saline (Day 26)/cloprostenol (Day 40); Group 4-cloprostenol (Day 26)/cloprostenol (Day 40). Double blind techniques were used in administering treatments and in assessing the response to treatment. Palpation of the reproductive tract per tectum and uterine biopsies were performed on 92 cows prior to each treatment at Day 26 and Day 40 postpartum. Progesterone concentrations were determined on milk samples collected prior to treatment. There were no significant differences among treatment groups with respect to services per conception, number of heats detected before first service and culling for infertility. Cloprostenol treatment at Day 26 appeared to delay the first estrus, but it reduced the number of days to conception after the first service. Cows receiving cloprostenol at Days 26 and/or 40 had a decreased calving-to-conception interval compared to controls (P=0.01). Sequential therapy with two doses of cloprostenol resulted in slightly better reproductive performance than either treatment on Day 26 or 40 alone. Treatment with cloprostenol resulted in a decrease in the subsequent incidence of pyometra (P<0.05). It is concluded that in the herd studied, cloprostenol therapy at Day 26 and/or 40 postpartum was beneficial to reproductive performance. Although it was anticipated that cloprostenol would be more effective in cows with elevated progesterone levels, the opposite was observed at the Day 26 cloprostenol treatment. Uterine biopsy at Days 26 and/or 40 had a detrimental effect on subsequent reproductive performance.

Journal Article↗
PubMed1988

Ultrastructural assessment of a blastocyst recovered from a cow with subclinical purulent endometritis.

A blastocyst was recovered from a cow with subclinical purulent endometritis from which Actinomyces pyogenes was isolated. Ultrastructurally the blastocyst appeared viable, although the zona pellucida and pervitelline cell debris were undergoing phagocytosis by neutrophils. An increase in lysosomal activity was observed in the inner cell mass, which may represent sublethal injury due to inflammatory alteration of the uterine milieu. It was concluded that the embryo was resistant to the bystander effect of the suppurative inflammation but that the altered uterine microenvironment may have caused sublethal blastocyst injury.

Journal Article↗
PubMed1988

The recovery of ureaplasmas from bovine embryos following in vitro exposure and ten washes.

Twenty-six unhatched embryos and ova were exposed to Ureaplasma diversum strain 2312 in vitro for 16 h and subsequently washed ten times. Fifteen of the embryos and their wash fluids were cultured for ureaplasmas. Of the remaining 11 embryos, six were incubated with rabbit anti-Ureaplasma immunoglobulin (RAI) and five were incubated with serum from naive rabbits(NRS), after which all were incubated with protein A gold and prepared for electron microscopy. On ultrastructural examination, ureaplasmas were observed on the outer surface of the zona pellucida of all 11 embryos. The ureaplasmas on the six embryos incubated with RAI were labeled with gold particles, while those on the five embryos incubated with NRS were not labeled. Ureaplasmas were recovered from all 15 of the cultured embryos and all of the first and second wash fluids as well as intermittently from the third, fourth, sixth, seventh, eighth and ninth wash but not fom the fifth or tenth wash. It was concluded that viable ureaplasmas adhered to the zona pellucida during in vitro exposure of bovine embryos and were not removed by ten washes.

Journal Article↗
PubMed1988

Hereditary parakeratosis in shorthorn beef calves.

Parakeratosis was diagnosed in 9 Shorthorn beef calves over a 4-year period. When pedigrees of these calves were analyzed, familial associations were strong. Thirty-six coefficients of relationship among all possible combinations of the 9 affected calves ranged from 0.5 to 39.8% and averaged 15.6%. All affected calves were descendants of bull A. Of 9 affected calves, 6 had bull A in their paternal and maternal pedigrees. The 3 remaining affected calves had bull A in their sire's pedigree and were born to 2 full-sib dams. Seemingly, parakeratosis in this Shorthorn herd was hereditary with the mode of inheritance being that of a simple autosomal recessive.

Animals↗
PubMed1988

Seroprevalence and association with abortion of leptospirosis in cattle in Ontario.

Sera were collected using a systematic random sampling from 348 cattle herds in Ontario, in proportion to the cattle population in different areas. One cow in five from 296 dairy herds and one in three from 52 beef herds were sampled. The sera were analyzed for prevalence of antibodies to Leptospira interrogans serovar grippotyphosa, hardjo, icterohaemorhagiae and pomona using the microscopic agglutination test. Herd seroprevalence (one or more animals with titer greater than or equal to 80) in beef and dairy herds combined was grippotyphosa 2%, hardjo 13.8%, icterohaemorrhagiae 10.1% and pomona 25.8%; 39% of all herds showed evidence of leptospiral infection with one or more serovars; 44.2% of 52 beef herds had serological evidence of infection with serovar hardjo compared to 8.4% of 296 dairy herds (P less than 0.0001). Seroprevalence of other serovars was not significantly different between beef and dairy herds. The proportion of beef animals seropositive for hardjo and for pomona increased with age, particularly for hardjo; 26.5% of beef animals aged nine years or over were seropositive for hardjo. Dairy animals showed a significant rise of hardjo but not pomona titers with age. The seroprevalence of pomona infection was significantly higher in dairy cattle in eastern Ontario than in other regions. Thirty-four (6.1%) of 553 aborted bovine fetuses had leptospires detected by immunofluorescence techniques. Sixty-five percent of these fetuses were from submissions made between November and January. Leptospires were identified as serovar hardjo by specific immunofluorescence. There appeared, however, to be a paradoxical serological response in that eight aborting cows had antibody titers to pomona rather than hardjo.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗
PubMed1987

A light and electron microscopical study of intranuclear cytoplasmic invaginations in interstitial cell tumours of dogs.

Intranuclear cytoplasmic invaginations, so-called "pseudoinclusions", were seen in all 7 interstitial cell tumours identified among 32 consecutive canine testicular tumours examined. The proportion of cells with intranuclear cytoplasmic invaginations varied from less than 1 per cent to 15 per cent. Similar "pseudoinclusions" were not seen in any other canine testicular tumours examined; this finding might be helpful in differential diagnosis, especially in less differentiated tumours. Histologically, the cytoplasmic invaginations appeared as round, eosinophilic, clearly demarcated intranuclear inclusions and stained with periodic acid-Schiff. Affected nuclei were enlarged. The process of progressive cytoplasmic invaginations into the nucleus and replacement of most of the nuclear volume of the neoplastic interstitial cells with cytoplasmic material was examined by transmission electron microscopy. Two or more cytoplasmic invaginations were sometimes present within a single nucleus. The nuclear membrane could be followed continuously around the cytoplasmic invaginations and nuclear pores were present in the membrane covering invaginations. The invaginations contained smooth and rough endoplasmic reticulum, vesicles, lipid vacuoles, myelin figures and disrupted membranous profiles. Bundles of interwoven cytoplasmic filaments were among the organelles seen in the invaginations in one tumour. Possible reasons for the formation of intranuclear cytoplasmic inclusions are discussed and maintenance of the normal ratio of nuclear surface to nuclear volume is suggested as the mechanism promoting formation of inclusions in interstitial cell tumours.

Animals↗
PubMed1987

Hormonal changes in sows after induced porcine parvovirus infection in early pregnancy.

Hormonal changes, lesions, and virus isolation studies were determined in sows after uterine artery inoculation with porcine parvovirus [( PPV], strain NADL-8) in early pregnancy. Two sows were given PPV on days 14 or 16 and were euthanatized and necropsied on day 35 after twice daily plasma collection for hormone measurement. Parvovirus was given to 4 sows on day 14 and to 4 sows on day 21 with 5 times daily plasma samples collected for 1 week. Sows were examined on days 21 and 28, respectively. Four control sows in each group on days 14 and 21 were given a placebo injection and were similarly studied. All embryos in all but 1 sow given PPV were in various stages of resorption at necropsy. Normal embryos were present in all control sows. Estrone sulfate values increased logarithmically, progesterone values remained stable, and concentrations of 13, 14-dihydro-15-keto-prostaglandin (PG) F2 alpha (PGFM), a PGF2 alpha metabolite, were less than 200 ng/ml for sows given a placebo. In contrast, sows with resorbing embryos did not have an increase in estrone sulfate values. A decrease in plasma progesterone values occurred in 9 of 10 sows inoculated with PPV; this decrease was accompanied by greater than or equal to 1 marked increase in PGFM concentrations. Quantitative assessment of the uterus revealed significantly greater cytoplasmic density in endometrial and glandular cell (P less than 0.01), a greater glandular epithelium height (P less than 0.05), and twice the number of glands (P less than 0.05) in control sows, compared with values in sows inoculated with PPV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Isolation of Leptospira hardjo from kidneys of Ontario cattle at slaughter.

Kidneys from 117 cattle from 110 Ontario farms were examined at slaughter for leptospires. Leptospira hardjo (hardjo-bovis A) was isolated from 11 kidneys and L. kennewicki from one. The isolations were all made (12/89, 13.5%) from beef cattle from feedlots, no isolates being obtained from dairy or beef cattle from extensive farms (0/28). Isolations were only made from cattle with antibody titers (greater than or equal to 20) against the serovars recovered. Isolation was more sensitive than immunofluorescence in identifying leptospira, particularly in animals with low antibody titers against L. hardjo. Leptospira were isolated from two kidneys with multiple gross lesions of focal nephritis, but there was no correlation between the presence of scanty kidney lesions and isolations of leptospira. Leptospira hardjo infection appears to be common in Ontario feedlot cattle.

Abattoirs↗
PubMed1987

The effect of intrauterine inoculation with Ureaplasma diversum on bovine fertility.

To determine the influence of Ureaplasma diversum on bovine fertility 11 uninfected virgin heifers with normal ovarian cyclic activity were randomly allocated to test or control groups. At a synchronized estrus, five test heifers were given an intrauterine broth inoculum containing 1.09 x 10(8) to 1.4 x 10(9) colony forming units of U. diversum and six control animals were infused with sterile ureaplasma broth medium. All animals were artificially inseminated within one hour of infusion. Pregnancy was diagnosed in one of five test heifers and all of six controls by serum progesterone concentrations measured to 25 days postinsemination. The difference in pregnancy rates between the two groups was statistically significant (p = 0.0152). It was concluded that under the conditions of this experiment U. diversum is capable of causing infertility in cattle.

Animals↗
PubMed1987

In vitro exposure of bovine morulae to Ureaplasma diversum.

Ureaplasma diversum has been associated with infertility in the cow experimentally and in naturally occurring cases. However, the pathogenic mechanism is undetermined. The purpose of this study was to determine whether ureaplasmas are pathogenic for bovine morulae in vitro. Twenty-one morulae were recovered from three superovulated, mature, Holstein cows six or seven days postestrus. The embryos were divided into three groups (A,B,C) and incubated for 16 hours at 37 degrees C in humidified air with 10% CO2. Group A was incubated in embryo culture medium alone, Group B was incubated in culture medium with sterile ureaplasma broth added and Group C was incubated in culture medium containing 1.7 X 10(6) colony forming units Ureaplasma diversum strain 2312. After incubation, the morulae were examined using an electron microscope. Structures morphologically identical to U. diversum were present on the outer surface of the zonae pellucidae of all the morulae exposed to the organism and none were present on the unexposed control embryos. No other morphological differences were observed in either the ureaplasma-exposed embryos or the two groups of control embryos. Ureaplasma diversum was isolated from three of the five embryos incubated in culture medium with sterile ureaplasma broth added. These three embryos were recovered from one donor cow which cultured positive for U. diversum from the vulva and flush fluid. This finding suggests that the contaminating organisms entered the embryo culture wells either in the embryo collection medium or attached to the embryos.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Inhibition of mammalian collagenases by thiol-containing peptides.

The following thiol-containing peptide analogues of the carboxyl side of the collagenase-sensitive bond of collagen were synthesized and tested as inhibitors of collagenases partially purified from homogenates of rabbit V-2 tumor and culture medium of pig synovium: HSCH2CH(CH3)CO-Ala-OEt (I), HSCH2CH(CH2Ph)CO-Ala-OEt (II), HSCH2CH[CH2CH(CH3)2]CO-Ala-OEt (III); HSCH2 CH-[CH2CH(CH3)2]CO-Ala-Gly-OEt (IV); HSCH2CH[CH2CH(CH3)2]CO-Ala-Gly-Gln (V). The compounds are listed in order of their inhibitory potency when assayed with nonfibrillar-acid-soluble calf skin collagen at pH 7.6, 35 degrees C. The best inhibitor (III) gave 50% inhibition between 1 and 4 microM. II was a competitive inhibitor with a Ki value of 75 microM. The enzymes preferred an isobutyl side chain at the 2-carbon position, and, where tested (III, IV), did not discriminate strongly between stereoisomers at the chiral 2-carbon. Increasing the length of the inhibitor did not markedly increase potency.

Animals↗
PubMed1986

The maternal to fetal transfer of immunoglobulins associated with placental lesions in sheep.

In this study we evaluated maternofetal transmission of immunoglobulins in ewes under conditions of altered placental morphology. Intravenous injection of human red blood cells was used to induce immunoglobulins in pregnant ewes. The hemagglutination test was used to detect antibody in maternal serum, fetal and placental fluids. Placental injury was induced by intravenous inoculation of Escherichia coli endotoxin or spores of Aspergillus fumigatus into pregnant ewes at days 99 or 100 of gestation respectively. Placental infarction, thrombosis of maternal placental vessels and variable neutrophil infiltrate characterized lesions produced by A. fumigatus. Endotoxin treated ewes developed marked placental edema, congestion, hemorrhage and focal loss of uterine epithelium. Human red blood cell agglutinating antibody was not detected in placental or fetal fluids obtained from ewes with either of the above placental lesions. Placentitis of undetermined etiology was observed in seven ewes. Two ewes had received A. fumigatus, two had received endotoxin and three were untreated ewes. Histological examination of their placentas revealed trophoblastic and endometrial epithelial necrosis and necrotizing vasculitis of the chorioallantois. Human red blood cell agglutinating antibody was detected only in the fetal and placental fluids of the seven ewes with these placental lesions. The nature of these lesions would have produced a functional confluence of the maternal and fetal circulations. Antibody transfer from dam to fetus was observed only in association with placental lesions which produced this confluence of circulations. The character of the placental lesions, rather than the mere presence of placental lesions apparently determined the transfer of immunoglobulins.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Veterinary↗