Cystic ovarian disease in dairy cattle: Diagnostic accuracy when using B-mode and color Doppler ultrasound

The most frequently reported definition of cystic ovarian disease in cattle is an abnormally persistent follicle (>7 to 10 d) with a diameter >25 mm. Discrimination between luteal and follicular ovarian cystic structures has traditionally been conducted by measuring the rim width of luteal tissue. The most common practice used in the field for diagnosis of cystic ovarian disease is examination by rectal palpation with or without the use of a B-mode ultrasound. Color Doppler ultrasound technology allows assessment of blood flow area measurements in the ovary, which has been proposed as a potential indirect measure for plasma progesterone (P4) concentrations. The objective of this study was to compare the diagnostic accuracy of differentiating luteal structures from follicular ovarian cysts using measures collected with B-mode and color Doppler transrectal ultrasonography. The definition of an ovarian cyst was a follicle greater than 20 mm in diameter in the absence of a corpus luteum that persisted for at least 10 d. A 3-mm luteal rim width was used to differentiate follicular and luteal cysts. A total of 36 cows were enrolled in the study during routine herd reproductive examination visits, with 26 and 10 having follicular and luteal cysts, respectively. Cows enrolled in the study were examined using a Mini-ExaPad mini ultrasound with color Doppler capabilities (IMV Imaging Ltd.). Blood samples were collected from each cow to measure P4 serum concentrations. History and signalment of each cow, including days in milk, lactation, times bred, days since last heat, milk composition, and somatic cell counts, were retrieved from an online database (DairyComp 305, Valley Agricultural Software). The accuracy of diagnosing follicular from luteal cysts based on luteal rim thickness was analyzed by receiver operating characteristic (ROC) curve using P4 as the gold standard, where P4 concentrations exceeding 1 ng/mL was defined as luteal, and all other structures with less P4 were considered follicular. Luteal rim and blood flow area were selected for further analysis because they presented the best ROC curves for differentiating cystic ovarian structures, with areas under the curve of 0.80 and 0.76, respectively. Luteal rim width of 3 mm was used as the cutoff standard in the study, resulting in sensitivity and specificity of 50% and 86%, respectively. Blood flow area of 0.19 cm² was used as the cutoff standard in the study, resulting in sensitivity and specificity of 79% and 86%, respectively. When combining the use of luteal rim width and blood flow area to differentiate cystic ovarian structures, a parallel approach resulted in sensitivity and specificity of 73% and 93%, respectively, whereas an in-series approach resulted in sensitivity and specificity of 35% and 100%, respectively. In conclusion, the use of color Doppler ultrasonography when discriminating between luteal and follicular ovarian cysts in dairy cattle resulted in higher diagnostic accuracy compared with using B-mode ultrasonography alone.

A novel risk assessment tool for bovine respiratory disease in preweaned dairy calves

Due to the increased morbidity and mortality of bovine respiratory disease (BRD) in dairy calves, as well as an increasing urgency for the judicious use of antimicrobials in farm animals, a comprehensive risk assessment tool for BRD in preweaned dairy calves has been designed based on a longitudinal and a cross-sectional study. As a multifactorial disease complex in which immune function stressors increase susceptibility to respiratory pathology, risk management programs for environmental and husbandry practices may be an effective approach for BRD control. Practices of known or suspected effect on BRD in preweaned calves have been explored in 2 large studies correlating management factors to BRD prevalence (BRD 100 study) and incidence (BRD 10K study) and forming the scores presented here. Priority was given to results from multivariable over univariable model estimates. However, when used, univariable model estimates were adjusted for confounders or stratified by effect modifiers if necessary. Regression coefficients were translated into scores, which are presented in a field-ready tool consisting of (1) a risk assessment questionnaire, which identifies the herd-specific risk factors and the risk scores associated with each; (2) the California BRD scoring system to estimate the BRD prevalence at the time of risk assessment for future comparison with the prevalence after interventions; and (3) the BRD control and prevention herd management plan, which can be used to plan and track the interventions identified. Scores for 100 dairies across California were used to benchmark a dairy's risk on a spectrum. With the help of the risk assessment tool, dairy producers, calf managers, and veterinarians may be able to adjust management factors that affect BRD risk on a farm and objectively monitor BRD prevalence before and after management interventions. As a result, the BRD risk assessment tool described here is the first comprehensive effort for herd-specific BRD control and prevention.

Management factors associated with bovine respiratory disease in preweaned calves on California dairies: The BRD 100 study

The objective of this cross-sectional study was to determine how management practices on California dairies may be associated with bovine respiratory disease (BRD) in preweaned calves. A convenience sample of 100 dairies throughout California, providing a study population of 4,636 calves, were visited between May 2014 and April 2016. During each farm visit, in-person interviews with the herd manager or calf caretaker were conducted to collect information about herd demographics, maternity pen, colostrum and calf management, herd vaccinations, and dust abatement. A random sample of preweaned calves was identified and evaluated for the presence of BRD using a standardized tool. A survey-adjusted generalized linear mixed model with a logit link function was fitted with calf as the unit of analysis and dairy as the random effect. Mean study herd size (±SE) was 1,718 (±189.9) cows. Survey-adjusted estimates of breed types in the sample were 81.6% (±0.6) Holstein, 13.1% (±0.4) Jersey, and 5.3% (±0.5) crossbred or other purebred breeds, and calf sex proportions were 73.8% (±1.0) female and 26.2% (±1.0) male. Overall survey-adjusted BRD prevalence in the study herds was 6.91% (±0.69). Housing factors positively associated with BRD were metal hutches compared with wood hutches [odds ratio (OR) = 11.19; 95% confidence interval (CI) = 2.80–44.78], calf-to-calf contact in calves >75 d of age (OR = 9.95, 95% CI = 1.50–65.86), feeding Holstein calves <2.84 L of milk or replacer per day (OR = 7.16, 95% CI = 1.23–41.68), and lagoon water used for flushing manure under hutches compared with no flush (OR = 12.06, 95% CI = 1.93–75.47). Providing extra shade over hutches (OR = 0.08; 95% CI = 0.02–0.37), feeding calves at least 90% saleable milk (OR = 0.27, 95% CI = 0.13–0.54) or pasteurized milk (OR = 0.10; 95% CI = 0.03–0.36), and feeding >5.68 L of milk or replacer per day to Jersey calves (OR = 0.04; 95% CI = 0.01–0.28) were negatively associated with BRD. Our study identified management practices on California dairies with variability and that may contribute to differences in BRD prevalence, which will be incorporated into a risk-assessment tool to control and prevent BRD in preweaned dairy calves.

Short communication: Identification of coagulase-negative staphylococcus species from goat milk with the API Staph identification test and with transfer RNA-intergenic spacer PCR combined with capillary electrophoresis

Coagulase-negative staphylococci (CNS) are the most commonly isolated bacteria from goat milk, but they have often been identified with phenotypic methods, which may have resulted in misclassification. The aims of this paper were to assess the amount of misclassification of a phenotypic test for identifying CNS species from goat milk compared with transfer RNA intergenic spacer PCR (tDNA-PCR) followed by capillary electrophoresis, and to apply the tDNA-PCR technique on different capillary electrophoresis equipment. Milk samples were collected from 416 does in 5 Californian dairy goat herds on 3 occasions during lactation. In total, 219 CNS isolates were identified at the species level with tDNA-PCR and subjected to the API 20 Staph identification test kit (API Staph; bioMérieux, Durham, NC). If the same species was isolated multiple times from the same udder gland, only the first isolate was used for further analyses, resulting in 115 unique CNS isolates. According to the tDNA-PCR test, the most prevalent CNS species were Staphylococcus epidermidis, Staphylococcus caprae, and Staphylococcus simulans. Typeability with API staph was low (72%). Although the API Staph test was capable of identifying the majority of Staph. epidermidis and Staph. caprae isolates, sensitivity for identification of Staph. simulans was low. The true positive fraction was high for the 3 most prevalent species. It was concluded that the overall performance of API Staph in differentiating CNS species from goat milk was moderate to low, mainly because of the low typeability, and that genotypic methods such as tDNA-PCR are preferred.

Pharmacokinetics of ceftiofur crystalline free acid after single and multiple subcutaneous administrations in healthy alpacas (Vicugna pacos)

Six adult male alpacas received one subcutaneous administration of ceftiofur crystalline free acid (CCFA) at a dosage of 6.6 mg/kg. After a washout period, the same alpacas received three subcutaneous doses of 6.6 mg/kg CCFA at 5-day intervals. Blood samples collected from the jugular vein before and at multiple time points after each CCFA administration were assayed for ceftiofur- and desfuroylceftiofur-related metabolite concentrations using high-performance liquid chromatography. Pharmacokinetic disposition of CCFA was analyzed by a noncompartmental approach. Mean pharmacokinetic parameters (± SD) following single-dose administration of CCFA were Cmax (2.7 ± 0.9 μg/mL); Tmax (36 ± 0 h); area under the curve AUC0→∞ (199.2 ± 42.1 μg·h/mL); terminal phase rate constant λz (0.02 ± 0.003/h); and terminal phase rate constant half-life t1/2λz (44.7 h; harmonic). Mean terminal pharmacokinetic parameters (±SD) following three administrations of CCFA were Cmax (2.0 ± 0.4 μg/mL); Tmax (17.3 ± 16.3 h); AUC0→∞ (216.8 ± 84.5 μg·h/mL); λz (0.01 ± 0.003/h); and t1/2λz (65.9 h; harmonic). The terminal phase rate constant and the Tmax were significantly different between single and multiple administrations. Local reactions were noted in two alpacas following multiple CCFA administrations.

Progesterone milk residues in goats treated with CIDR-G(®) inserts

Progesterone (P4)-impregnated intravaginal controlled internal drug-releasing devices (CIDRs) have been used worldwide for estrus synchronization in ruminants. CIDRs serve to place all treated animals in the luteal phase of the estrous cycle. The objectives of this study were to compare P4 concentrations in milk from normal reproductively cycling, CIDR-treated, and pregnant goats. CIDRs were placed in treatment goats on day 0 and removed on day 19. Milk was collected daily from day 0 to day 21 from control and CIDR-treated goats and for 5 consecutive days between 40 and 60 days of gestation from pregnant does. Milk P4 was plotted against time (in days) for each individual, and the area under the curve (AUC) was calculated as an estimate of total milk P4. The AUC(day 0-21) for control and CIDR-treated goats were 29.5 ± 11.9 and 33.7 ± 6.6 d·ng/mL, respectively (P = 0.77). The highest single-day and highest 5-day average P4 values for each animal were also compared among groups. Single-day peak P4 levels were 4.8 ± 1.5, 4.0 ± 1.0, and 6.0 ± 0.4 ng/mL for control, CIDR-treated, and pregnant goats (P = 0.42). The highest 5-day average P4 concentrations were 3.6 ± 1.3, 2.9 ± 1.8, and 4.2 ± 0.3 for control, CIDR-treated, and pregnant goats (P = 0.56). The results of this study show that intravaginal P4 CIDR devices inserted for 19 days in healthy goats resulted in milk P4 levels similar to or less than those endogenously produced during diestrus or pregnancy.

Production and Processing of Milk from Transgenic Goats Expressing Human Lysozyme in the Mammary Gland

The potential for applying biotechnology to benefit animal agriculture and food production has long been speculated. The addition of human milk components with intrinsic antimicrobial activity and positive charge to livestock milk by genetic engineering has the potential to benefit animal health, as well as food safety and production. We generated one line of transgenic goats as a model for the dairy cow designed to express human lysozyme in the mammary gland. Here we report the characterization of the milk from 5 transgenic females of this line expressing human lysozyme in their milk at 270 microg/mL or 68% of the level found in human milk. Milk from transgenic animals had a lower somatic cell count, but the overall component composition of the milk and milk production were not different from controls. Milk from transgenic animals had a shorter rennet clotting time and increased curd strength. Milk of such nature may be of benefit to the producer by influencing udder health and milk processing.

Hot Topic: Using a Stearoyl-CoA Desaturase Transgene to Alter Milk Fatty Acid Composition

Stearoyl-CoA desaturase enzyme converts specific medium- and long-chain saturated fatty acids to their monounsaturated form. Transgenic goats expressing a bovine beta-lactoglobulin promoter-rat stearoyl-CoA desaturase cDNA construct in mammary gland epithelial cells were produced by pronuclear microinjection. The fatty acid composition of milk from 4 female transgenic founders was analyzed on d 7, 14, and 30 of their first lactation. In 2 animals, the expression of the transgene changed the overall fatty acid composition of the resulting milk fat to a less saturated and more monounsaturated fatty acid profile at d 7 of lactation; however, this effect diminished by d 30. In addition, one animal had an increased proportion of the rumen-derived monounsaturated fatty acid C18:1 trans11 converted by stearoyl-CoA desaturase to the conjugated linoleic acid isomer C18:2 cis9 trans11. Milk that has higher proportions of monounsaturated fatty acids and conjugated linoleic acid may have benefits for human cardiovascular health.

Immune responses in pregnant cattle and bovine fetuses following experimental infection with Neospora caninum

Humoral and cell-mediated immune (CMI) responses [i.e. proliferative responses and gamma interferon (IFN-gamma) production], were elicited in five cows infected between 159 and 169 days of gestation by a combined intravenous-intramuscular inoculation of Neospora caninum tachyzoites. Analysis of antigen-specific immunoglobulin (IgG) subclasses revealed a predominant IgG2 response in two cows, a mixed IgG1-IgG2 response in two other cows and a predominant IgG1 response in one cow. No correlation was found between IgG2 titers and IFN-gamma levels. CD4-T cells were responsible for the CMI responses in peripheral blood mononuclear cells from three infected cows. All five fetuses removed from infected dams at week 9 post-infection (219-231 days of gestation) mounted strong Neospora-specific humoral responses and had a predominant IgG1 response, regardless of their ability to produce IFN-gamma. However, CMI responses were highly variable between fetuses. These data indicate the complexity of the immune mechanisms associated with Neospora infection in both the dams and their fetuses.

Rat glutathione S-transferase M4-4: an isoenzyme with unique structural features including a redox-reactive cysteine-115 residue that forms mixed disulphides with glutathione

Although the existence of the rat glutathione S-transferase (GST) M4 (rGSTM4) gene has been known for some time, the corresponding protein has not as yet been purified from tissue. A recombinant rGSTM4-4 was thus expressed in Escherichia coli from a chemically synthesized rGSTM4 gene. The catalytic efficiency (k(cat)/K(m)) of rGSTM4-4 for the 1-chloro-2,4-dinitrobenzene (CDNB) conjugation reaction was 50-180-fold less than that of the well-characterized homologous rGSTM1-1, and the pH optimum for the same reaction was 8.5 for rGSTM4-4 as opposed to 6.5 for rGSTM1-1. Molecular-modelling studies predict that key substitutions in the helix alpha4 region of rGSTM4-4 account for this pK(a) difference. A notable structural feature of rGSTM4-4 is the Cys-115 residue in place of the Tyr-115 of other Mu-class GSTs. The thiol group of Cys-115 is redox-reactive and readily forms a mixed disulphide even with GSH; the S-glutathiolated form of the enzyme is catalytically active. A mutated rGSTM4-4 (C115Y) had 6-10-fold greater catalytic efficiency than the wild-type rGSTM4-4. Trp-45, a conserved residue among Mu-class GSTs, is essential in rGSTM4-4 for both enzyme activity and binding to glutathione affinity matrices. Antibodies directed against either the unique C-terminal undecapeptide or tridecapeptide of rGSTM4 reacted with rat and mouse liver GSTs to reveal an orthologous mouse GSTM4-4 present at low basal levels but which is inducible in mouse liver. This subclass of rodent Mu GSTs with redox-active Cys-115 residues could have specialized physiological functions in response to oxidative stress.

Fetal leukocyte trafficking as a stimulus for the production of maternal antibodies in the goat

The production of antibodies during pregnancy or after parturition is a natural occurrence in many mammalian species. Fetal cells have been detected in the peripheral blood of women and mice and are thought to be the immune stimulus for antibody production. The aim of this study was to investigate if the production of maternal anti-fetal antibodies during ruminant pregnancy is the result of fetal leukocyte trafficking across the placenta. Maternal pregnancy serum was collected from 94 does whose fetuses received sheep hematopoietic stem cells via in utero transplantation at 49 to 62 d of gestation. Serum samples were collected before surgery and at weekly intervals throughout gestation. A lymphocyte microcytotoxicity assay was used to screen the serum samples from does that carried chimeric fetuses to term (n = 75). Of these 75 does, 28 parous does had presurgery serum that contained alloreactive antibodies. Nine of the 75 does had nonreactive presurgery serum, but they produced alloreactive antibody titers during gestation. Xenoreactive antibodies were detected in the pregnancy sera from 2 of the 75 does tested. Hemolytic assays confirmed the species-specificity of the xenoreactive serum from these 2 does. In view of the fact that hematopoietic cells were the only source of anti-sheep antibody stimulation in this model, we propose that fetal leukocyte trafficking does take place across the caprine placenta.

Evidence against humoral immune attack as the cause of sheep-goat interspecies and hybrid pregnancy failure in the DOE

The failure of interspecies and hybrid pregnancies between the domestic sheep (Ovis aries) and goat (Capra hircus) is not completely understood. The sheep-goat hematopoietic chimera is a unique model for studying the role of the maternal immune response in failure of interspecies and hybrid pregnancies between these species. Hematopoietic chimeras were created by in utero transplantation of sheep fetal liver cells into goat fetuses. The resulting chimeric females were recipients of sheep demi-embryos genetically identical to their sheep cells and/or were bred to a ram to create a hybrid pregnancy. Pregnancy sera were analyzed for the presence of anti-species antibodies (Ab) using a lymphocyte microcytotoxicity assay. None of the concepti survived to term. Gross and histological evaluations of two interspecies sheep concepti revealed abnormal placentome formation. The humoral immune response of several hematopoietic chimeras to the challenging concepti differed from control animals. We observed delayed onset of Ab production, low and absent titers, and persistent Ab titers with delayed fetal death. Ultrasonography typically revealed normal fetal development associated with high volumes of placental fluids and retarded placentome development. We conclude that fetal death was associated with abnormal placental development that was not the result of maternal humoral immune attack.

Acetaminophen selectively reduces glioma cell growth and increases radiosensitivity in culture

Glioblastoma multiforme (GBM) is a highly lethal brain cancer. Using cultures of rodent and human malignant glioma cell lines, we demonstrated that millimolar concentrations of acetylsalicylate, acetaminophen, and ibuprofen all significantly reduce cell numbers after several days of culture. However, their mechanisms of action may vary, as demonstrated by (1) differences in the morphological changes produced by these compounds; (2) varied responses to these drugs with respect to toxicity kinetics; and (3) respective rates of cell proliferation, DNA synthesis, and mitotic index. We studied the effects of acetaminophen on relative cell number further. Evidence is presented that acetaminophen induced cell death by an apoptotic mechanism after a brief burst of mitosis in which cell numbers increased transiently, followed by a reduction in cell number and an increase in DNA fragmentation, as evidenced by terminal deoxytransferase-mediated dUTP-biotin nick end labeling (TUNEL) analysis. Using cultures of adult human brain and embryonic rat brain, we demonstrated that glioma cells were several-fold more sensitive to acetaminophen than normal brain cells in culture. Finally, subtoxic doses of acetaminophen increased the sensitivity of the human glioma cells in culture to ionizing radiation. Taken together, these results suggest that acetaminophen may prove to be a useful therapeutic agent in the treatment of human brain tumors.

Hematopoietic Stem Cell Transplantation in Utero Produces Sheep–Goat Chimeras

Both allogeneic and xenogeneic hematopoietic chimera models have been developed, including fetal sheep models that demonstrated high levels of stable, multilineage engraftment created by in utero hematopoietic stem cell transplantation. The aim of this study was to test the efficacy of in utero transplantation to create xenogeneic sheep-goat hematopoietic chimeras. Fetal liver cells and T-cell-depleted adult bone marrow were tested as sources of hematopoietic stem cells. Donor cells were injected intraperitoneally into 130 recipient fetuses between 49 and 62 days of gestation. Groups 1 and 2 received crude fetal liver cell preparations. Group 3 received fetal liver cells that were incubated overnight in a phytohemagglutinin-stimulated lymphocyte-conditioned medium (PHA-LCM). In Group 4, hematopoietic stem cells were concentrated by using additional density separations. Group 5 fetal recipients received low-density, T-cell-depleted adult bone marrow cells. In Group 1, fetuses were accessed via hysterotomy. Hematopoietic stem cells were injected into Groups 2, 3, 4, and 5 without cutting through the uterine wall. Fetal survival in the five groups ranged from 56 to 100%. The percentage of chimeras from injected fetuses ranged from 43 to 92% by FACS and PCR analyses; however, levels of chimerism were low (<1%). The highest rates of chimerism were found among recipients of low-density fetal liver cells. Despite the pre-immunocompetent status of the fetal recipients and the genetic similarities between sheep and goats, high levels of engraftment were not observed. The consistently low levels of chimerism observed in this study, as well as the poor results recently reported by others using these procedures, indicate that significant barriers exist to transplanting hematopoietic stem cells in utero.

Successful pregnancy in goats carrying their genetically identical conceptus

Mammalian pregnancies are naturally allogeneic, but syngeneic pregnancies have been carried to term in laboratory animal species. The need for maternal immune recognition during mammalian pregnancy is still unclear. Allogeneic pregnancies are protected from maternal immune attack by the nature of the trophoblast and its interactions with maternal tissues at the maternal-fetal interface. Syngeneic pregnancy models and the success of pregnancies in immunosuppressed mice challenge the necessity of a maternal immune response in mammals. This study was designed to investigate if outbred, domestic sheep and goats can successfully establish and maintain a syngeneic pregnancy. Embryo splitting and cryopreservation techniques were used to enable sheep and goat demi-embryos to be transferred to genetically identical females. Allogeneic pregnancies were established from the transfer of demi-embryos subjected to the same manipulations to assess demi-embryo survival and pregnancy rates under conventional immune compatibility conditions. Syngeneic pregnancies were established and carried to term in goats (2/11) but not in sheep (0/24). Microsatellite and DNA fingerprinting analyses confirmed that each kid was a genetically identical twin to the female that carried it to term. Our results demonstrated that genetic disparity is not required for the establishment and maintenance of pregnancy in goats, but our results were inconclusive for sheep.

A POLYGEN-adjuvanted killed Neospora caninum tachyzoite preparation failed to prevent foetal infection in pregnant cattle following i.v./i.m. experimental tachyzoite challenge

Cattle immunised with a POLYGEN-adjuvanted killed Neospora caninum tachyzoite preparation were previously shown to produce interferon (IFN)-gamma at levels similar to those of tachyzoite-infected cattle. In view of the critical role of IFN-gamma in resistance of mice to N. caninum infection, these results prompted us to test the POLYGEN-adjuvanted preparation in pregnant cattle to determine whether it will be able to prevent foetal infection following an experimental tachyzoite challenge. Seven heifers were immunised at 35 and 63 days of gestation with the POLYGEN-adjuvanted preparation, while five heifers were inoculated with POLYGEN alone at the same days of gestation. Four weeks later, all heifers were challenged with a combined i.v./i.m. inoculation of tachyzoites. The same challenge was given to seven unimmunized heifers at the same stage of gestation. An additional unimmunized heifer was inoculated with uninfected monolayer cell culture material. All challenged heifers, immunized and unimmunized, had infected foetuses. Immunized heifers developed both parasite-specific humoral and cellular immune responses, characterised by increased IFAT titres, a predominant IgG1 response, elevated lymphoproliferative response and IFN-gamma production. Following tachyzoite challenge, they developed an anamnestic humoral response and produced similar amounts of IgG1 and IgG2 antibodies, but did not have an anamnestic cellular immune response. The lack of anamnestic cellular immune response and/or the large i.v/i.m tachyzoite inoculum may have contributed to the failure of the preparation.

Single-arm, open-label phase II study of intravenously administered tirapazamine and radiation therapy for glioblastoma multiforme

PURPOSE

This phase II study tested the efficacy and safety of tirapazamine (Sanofi Synthelabo Research, Malvern, PA), a bioreductive agent, in glioblastoma multiforme (GBM) patients. The patients were staged according to a model constructed by a recursive partitioning analysis (RPA) of glioma patients in prior Radiation Therapy Oncology Group (RTOG) trials and compared with a matched standard population, as predicted by the model.

PATIENTS AND METHODS

A total of 124 patients diagnosed with a GBM were treated with radiation therapy and intravenous tirapazamine between January 27,1995, and April 25,1997. All patients received 60 Gy in 2-Gy fractions. Tirapazamine was delivered three times a week for 12 treatments during radiotherapy. Fifty-five patients received tirapazamine at 159 mg/m(2). A second dose level, 260 mg/m(2), was opened, and 69 patients were entered.

RESULTS

There was no significant survival advantage to the drug in any RPA class at either dose level. The median survival time was 10.8 months for the patient population treated with the 159-mg/m(2) dose of tirapazamine and 9.5 months for the group treated with the 260-mg/m (2) dose of tirapazamine. Survival times by RPA class for patients receiving tirapazamine at 159 mg/m(2) were 27.4 months (class III), 10.8 months (class IV), 7.9 months (class V), and 3.8 months (class VI). Survival times by RPA class for patients receiving tirapazamine at 260 mg/m(2) were 16.2 months (class III), 10.3 months (class IV), 5. 1 months (class V), and 1.3 months (class VI). Patients in RPA class III treated in the 159 mg/m(2) dose arm had a notably longer survival than patients in the RTOG database RPA class III, but the difference did not reach statistical significance. There were no fatal toxicities. Grade 3/4 toxicities were more frequent at the higher dose level.

CONCLUSION

Survival in the population treated with radiation and tirapazamine was equivalent to the control population. Patients in RPA class III treated with radiation and tirapazamine at the 159-mg/m(2) dose had a longer survival when compared with the historical controls. The improvement in survival did not reach statistical significance. Toxicity was acceptable in both treatment arms, but grade 3/4 toxicities were more frequent in the higher dose regimen.

Progestin implants can rescue demi-embryo pregnancies in goats: a case study

Survival after transfer of demi-embryos (i.e., half-embryos produced by embryo splitting) to recipients usually is lower than survival after transfer of intact embryos. Reduced survival after demi-embryo transfer could be due to loss of viability after splitting, failure of a viable demi-embryo to prevent corpus luteum (CL) regression in the recipient female, or a combination of factors. From a retrospective analysis of pregnancy and embryo survival rates after demi-embryo transfer in sheep and goats, we report the rescue of caprine demi-embryo pregnancies in which CL regression occurred at the end of diestrus despite the presence of a viable conceptus in the uterus with progestin implants. Day 5 or 6 morulae and blastocysts were flushed from superovulated ewes and does and split into demi-embryos of approximately equal halves. Demi-embryos were either transferred fresh to synchronized recipients of the homologous species or frozen in liquid nitrogen. Approximately half of the recipient does and ewes were treated with norgestomet implants on Day 10 of the embryo transfer cycle and again 2 wk later. Serum collected on Day 25 from recipients with implants was assayed for progesterone to determine if a CL of pregnancy had been maintained. Pregnancy was diagnosed by ultrasonography on Day 35 of gestation. Corpus luteum regression occurred despite the presence of a viable conceptus in the uterus in 6 of 55 progestin-treated caprine demi-embryo recipients and in 0 of 66 ovine demi-embryo recipients. Five of the caprine pregnancies were maintained to term with norgestomet implants and produced 5 live kids. The sixth fetus, which was carried by a progestin implant-treated 8-mo-old doeling, died at approximately 50 d of gestation. These results suggest that, at least in goats, some demi-embryos may provide inadequate signaling for maternal recognition of pregnancy, and such pregnancies can be rescued with progestin treatment to the doe.

Selective expression of a glutathione S-transferase subclass during spermatogenesis

Levels of the hGSTM3 glutathione S-transferase (GST) subunit in testis of the human fetus and infant were found to be only a small fraction of those in adults. To understand these observations and to determine whether hGSTM3 subunit expression is developmentally and/or hormonally regulated, an experimental model based on the rat testis homologue (subunit rGSTM5) was used. For prepubertal rats, testicular rGSTM5 subunit levels were very low, but a sharp increase was observed between weeks 6 and 7 of development, when testicular growth includes increased numbers of germ cells associated with spermatogenesis. In adult hypophysectomized rats, the rGSTM5 subunit content of testis decreased progressively over 5 weeks, at which time the subunit was barely detectable. In contrast, the other GST subunit types did not vary significantly during development or after hypophysectomy. These results suggest that rGSTM5 subunits in rat testis could originate from spermatogenic cells. Accordingly, GSTs were purified from human sperm, and it was shown that the hGSTM3 subunit was, by a large measure, the predominant form. These data are consistent with the notion that the differential expression of hGSTM3 during human testicular development can also be explained on the basis of its preferential location in germs cells.

Overview of diseases and drug needs for sheep and goats. Veterinarians' and producers' perspectives

A survey among small ruminant veterinary practitioners and producers of the United States was conducted to determine the most important health problems of sheep and goats and the need for drugs to treat these diseases. Gastrointestinal nematodes and pneumonia were the most important health concerns. Ceftiofur, long acting tetracyclines, penicillins, tilmicosin and enrofloxacin were the antibiotics most needed. The approval of ivermectin and albendazole for goats, and fenbendazole for sheep were among the most common requests for anthelmintics. Veterinarians also stressed the need for drugs to manipulate the estrous cycle, anti-inflammatory drugs, analgesics and anesthetics. Among the viral diseases, lentivirus infections (ovine progressive pneumonia and caprine arthritis encephalitis) and soremouth were the greatest concerns among veterinarians and producers. Both groups indicated that the availability of a generic antiviral drug would be important. The lack of a rabies vaccine was of great concern particularly among goat producers. Extra-label use of drugs in food animals may result in drug residues in tissues that may be hazardous for consumers. Therefore; in order for producers to provide high quality, safe products while remaining competitive in a global market economy, research to determine safety levels and tissue depletion times of new drugs is an urgent need for the sheep and goat industry.

A modified agglutination test for Neospora caninum: development, optimization, and comparison to the indirect fluorescent-antibody test and enzyme-linked immunosorbent assay

Current serologic tests used to detect antibodies to Neospora caninum require species-specific secondary antibodies, limiting the number of species that can be tested. In order to examine a wide variety of animal species that may be infected with N. caninum, a modified direct agglutination test (N-MAT) similar to the Toxoplasma gondii modified direct agglutination test (T-MAT) was developed. This test measures the direct agglutination of parasites by N. caninum-specific antibodies in serum, thus eliminating the need for secondary host-specific anti-isotype sera. The N-MAT was compared to the indirect fluorescent-antibody test (IFAT) and the enzyme-linked immunosorbent assay (ELISA) with a "gold standard" serum panel from species for which secondary antibodies were available (n = 547). All positive samples tested were from animals with histologically confirmed infections. Up to 16 different species were tested. The N-MAT gave a higher sensitivity (100%) and specificity (97%) than the ELISA (74 and 94%, respectively) and had a higher sensitivity but a lower specificity than the IFAT (98 and 99%, respectively). The reduced specificity of the N-MAT was due to false-positive reactions in testing fetal fluids with particulate matter or severely hemolyzed serum. Overall, the N-MAT proved to be highly sensitive and specific for both naturally and experimentally infected animals, highly reproducible between and within readers, easy to use on large sample sizes without requiring special equipment, and useful in testing serum from any species without modification.

Glutathione S-transferases in human renal cortex and neoplastic tissue: enzymatic activity, isoenzyme profile and immunohistochemical localization

1. Glutathione S-transferase (GST) activity in the cytosol of renal cortex and tumours from eight men and eight women was measured using 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate. GST activities ranged from 685 to 2192 nmol/min/mg protein in cortex (median 1213) and from non-detectable (minimum 45) to 2424 nmol/min/mg protein in tumours (median 469). The activities in the tumours were lower than those in the normal cortices (p < 0.05). 2. In men, the activity in the cortical cytosol was in all cases higher than that measured in the corresponding tumours (p < 0.05). In women, the difference in activity between cortices and tumours was not significantly different (p > 0.05). 3. The age of the patients ranged from 42 to 81 years (median 62) and was not found to play a role in the levels of GST activity observed in cortex or in renal tumours from either sex. 4. Immunoblotting and immunohistochemical studies confirmed that GST-alpha was the predominant form expressed both in normal cortex and tumour and probably accounted for most of the GST activity present in these samples. GST-mu and GST-phi were expressed in both tumours and normal cortex and, while in some cases the level of expression in the cortices was higher than that found in the tumours, the reverse was also observed. Within the GST-mu class, GST M1/M2 was only detected in one sample (tumour), which showed the highest overall expression of GST-mu. GSTM3 was the predominant isoenzyme of the mu class in normal and tumour tissue, whereas GTM4 and GSTM5 were not detected. 5. These differences could have functional significance where xenobiotics or cytotoxic drugs are specific substrates for the different classes of GSTs.

Human testicular glutathione S-transferases: insights into tissue-specific expression of the diverse subunit classes

Cytosolic glutathione S-transferase (GST) subunits from human testis were resolved by HPLC and unambiguously identified by combined use of peptide sequence-specific antisera and electrospray ionization mass spectrometry (ESI MS). Allelic variants of hGSTP1, hGSTM1 and hGSTA2 were distinguished on the basis of observed differences in their molecular masses. Relative amounts of the multiple different subunit types in various human tissues were determined from HPLC profiles. From this type of analysis, tissues from hGSTM1 null allele individuals were readily discerned at the protein level; liver was the only tissue in which the hGSTM1 subunit was the major mu-class GST. hGSTM4 and hGSTM5 subunits were found at very low levels in all tissues examined. By far the tissue richest in the unique hGSTM3 subunit was testis, although brain also has significant levels.

Rationale for reclassification of a distinctive subdivision of mammalian class Mu glutathione S-transferases that are primarily expressed in testis

A rat testicular Mu-class glutathione S-transferase (GST) resolved by reversed-phase high performance liquid chromatography cross-reacted with peptide sequence-specific antisera raised against the human hGSTM3 subunit. Electrospray ionization mass spectrometry indicated that this rat GST subunit (designated rGSTM5 in this report) has a significantly greater molecular mass (26,541 Da) than the other rat GST subunits. The mouse homologue (mGSTM5 subunit) was also identified and characterized by high performance liquid chromatography and electrospray ionization mass spectrometry. Sequence analysis of rGSTM5 peptide fragments and the sequence deduced from a cDNA clone showed that the protein is highly homologous to the hGSTM3 and murine mGSTM5 subunits. All three GSTs of this subclass have N- and C-terminal extensions with C-terminal cysteine residues, but the two penultimate amino acids near the C terminus are divergent in the three species. The proteins of this class Mu subfamily have similar catalytic specificities and mechanisms, are all cysteine rich, are found mainly in testis, and share characteristics that distinguish them from other GSTs. Moreover, the rGSTM5 subunit isolated from rat testis was not found in heterodimeric combination with other common Mu-class GST subunits. As the rGSTM5, mGSTM5, and hGSTM3 subunits are structurally more closely related to each other than they are to other Mu GSTs, it is proposed that they be considered a functionally distinct and separate subfamily within class Mu. The identification of this unique mammalian GST subclass could advance strategies for interspecies comparisons of GSTs and provides a rodent model for studies on functions and regulatory mechanisms for human GSTs.

Negligible prevalence of antibodies against Trypanosoma cruzi among blood donors in the southeastern United States

Trypanosoma cruzi, a hemoflagellate, causes Chagas' disease and is endemic throughout Latin America. Increasing Latin American immigration to the United States has enhanced concern about transmission of Chagas' disease by infected donor blood. The insect vector and parasites also have been found in the southeastern United States. Autochthonous infection of several species of wild and domesticated mammals suggests that the general human population also may be at risk. To assess the prevalence of antibodies to T cruzi in humans, randomly selected donor blood was screened. Initial screening was performed by indirect hemagglutination (1:4 initial serum dilution) and at least one of three different enzyme immunoassays. All samples testing positive by at least one screening method were tested by radioimmunoprecipitation and indirect immunofluorescence supplemental methods, which were used for confirmation and calculation of specificity. Of the 6,013 serum samples evaluated, 85 tested positive by one screening method. Only 10 of the samples tested positive by more than one method. The percentages of positive screening tests are 0.05% by indirect hemagglutination and 0.06%, 0.91%, 3.97% by Abbott Laboratories (Abbott Park, Ill), Gull (Gull Laboratories, Salt Lake City, Utah), and Polychaco (Polychaco S.A.I.C., Buenos Aires, Argentina) enzyme immunoassays, respectively. All samples were negative by radioimmunoprecipitation and indirect immunofluorescence. These results suggest that although parasite and vector are found in the southeastern United States and both infect mammals, the risk of natural infection to humans in this region seems to be negligible. There was variation in positivity among different screening methods. The highest percentage of positive results was with the enzyme immunoassay, in which the binding of serum antibodies to antigens is amplified by enzymatic reactions.

Subunit diversity and tissue distribution of human glutathione S-transferases: interpretations based on electrospray ionization-MS and peptide sequence-specific antisera

Uncertainties about the composition and identities of glutathione S-transferases (GSTs) in human tissue have impeded studies on their biological functions. A rigorous protocol has therefore been developed to characterize the human proteins. Cytosolic GST subunits were resolved by reverse-phase HPLC methods, individual components were assigned to Alpha, Mu and Pi classes on the basis of their immunoreactivities, and peptide-sequence-specific antisera were used to distinguish among five different Mu-class subunits (GSTM1-GSTM5). Each subunit type was characterized and identified unambiguously by electrospray ionization-MS. Acetylation of N-terminal residues in the GSTA1, GSTA2, GSTM3 and GSTM4 subunits were the only natural post-translational modifications detected. The unique structure of GSTM3, with N- and C-terminal peptide extensions predicted from cDNA sequences, was confirmed. Only testis and brain were rich sources of GSTM3 subunits. Subunit profiles were distinct and characteristic of the particular tissue type, and this tissue specificity in GST expression was evident even in organs from different individuals. For instance, livers had relatively simple GST compositions, consisting of a preponderance of Alpha-class subunits and GSTM1 (when present). By contrast, representation of most subunit types was a characteristic feature of testis, which had the highest levels of GSTs. GSTM4 and GSTM5 subunits, here identified for the first time in human tissue extracts, were minor components, with GSTM5 found only in brain, lung and testis. Specimens devoid of GSTM1 subunits, particularly those from null-genotype individuals, were readily discerned at the protein level. Liver was the only rich source of the GSTM1 subunit (although it also constituted a major fraction of adrenal GSTs), and so the functional consequences of the GSTM1 gene deletion are likely to vary in extrahepatic tissues.

Detection of Neospora sp. from infected bovine tissues by PCR and probe hybridization

Neospora sp. can cause fetal abortion or neurological disease in congenitally infected calves. Latent tissue stages in infected cows may contribute to vertical transmission of Neospora sp. from dam to offspring in multiple pregnancies. In this investigation, the polymerase chain reaction (PCR) and Neospora-specific assay were employed to detect Neospora sp. by amplification of nuclear small-subunit rRNA gene sequences in infected cattle tissues. Tissues from 11 cattle, including 6 experimentally and 2 naturally infected cows, 1 naturally infected newborn calf, and 2 uninfected control cows, were evaluated in this study. Neospora-specific PCR products were amplified from DNAs of different bovine tissues, including brain, spinal cord, heart, lung, kidney, diaphragm, skeletal muscle, and placenta, as well as amniotic fluid samples of infected cattle. The PCR-based amplification and probe hybridization system proved useful in assessing the location of tissue-stage parasites in naturally and experimentally infected cattle, even when Neospora sp. antibody titers fall below normal cut-off values by an indirect immunofluorescent antibody test.

Evidence of vertical transmission of Neospora sp infection in dairy cattle

OBJECTIVE

To determine whether heifers with naturally acquired congenital exposure to Neospora sp would transmit the infection to their offspring during gestation.

DESIGN

Prospective cohort study.

ANIMALS

Neonatal heifers on a dairy with a history of Neospora sp infections were selected for the study on the basis of their serum titers to Neospora sp, as determined by the use of indirect fluorescent antibody testing. Seropositive heifers (n = 25) had titers > or = 1:5,120 and seronegative heifers (25) had titers < or = 1:80. All heifers were raised and bred on the dairy, and samples were obtained from heifers and their calves at the time of calving.

PROCEDURE

Blood samples were tested for Neospora sp antibodies. Histologic evaluations, Neospora sp immunohistochemical examinations, and protozoal culturing were performed on samples obtained from selected offspring (second-generation calves).

RESULTS

Seropositive heifers gave birth to calves with titers > or = 1:1,280 to Neospora sp. All offspring from seropositive heifers that were necropsied had evidence of Neospora sp infection. All seronegative heifers and their offspring had titers < 1:80 to Neospora sp.

CLINICAL IMPLICATIONS

Congenitally acquired Neospora sp infection can persist in clinically normal heifers and be transmitted transplacentally to their offspring. Vertical transmission can be a way by which neosporosis is maintained in herds.

Risk factors for transmission and methods for control of caprine arthritis-encephalitis virus infection

The major route of transmission of caprine-encephalitis virus (CAEV) is through the ingestion of CAEV-infected colostrum or milk. Less efficient routes of transmission are associated with prolonged contact with infected goats and are reviewed in this article. Prevention of CAEV is based on the removal of kids from their dam at birth, and feeding the kids heat-treated colostrum and pasteurized milk until weaning. Serologic testing and segregation or culling of seropositive goats is necessary to minimize horizontal transmission of CAEV.

Identification of bovine Neospora parasites by PCR amplification and specific small-subunit rRNA sequence probe hybridization

Neospora is a newly recognized genus of pathogenic coccidia, closely related to Toxoplasma gondii, that can cause abortion or congenital disease in a variety of domestic animal hosts. On the basis of the small-subunit rRNA gene sequences of Neospora spp. and other apicomplexa coccidia, oligonucleotide primers COC-1 and COC-2 were used for PCR amplification of conserved sequences of approximately 300 bp in size. A Neospora-specific chemiluminescent probe hybridized to Southern blots of amplification products from Neospora DNA but not to Southern blots with amplified DNA from the other coccidian parasites tested. A Toxoplasma-specific probe whose sequence differed from that of the probe for Neospora spp. by a single base pair was used to distinguish these parasites by specific Southern blot hybridization. The PCR system detected as few as one Neospora tachyzoite in the culture medium or five tachyzoites in samples of whole blood or amniotic fluid spiked with Neospora parasites. In addition, Neospora PCR products were successfully amplified from whole blood and amniotic fluid samples of experimentally infected bovine and rhesus macaque fetuses. These results indicate that this PCR and probe hybridization system could be a valuable adjunct to serology and immunohistochemistry for the diagnosis of Neospora infections in bovine or primate fetuses.

Radiosurgery for the treatment of previously irradiated recurrent primary brain tumors and brain metastases: initial report of radiation therapy oncology group protocol (90-05)

PURPOSE

To determine the maximum acutely tolerable dose of single fraction radiosurgery in patients with recurrent previously irradiated primary brain tumors or brain metastases.

METHODS AND MATERIALS

Between August 1990 and September 1993, 102 analyzable patients were entered on Radiation Therapy Oncology Group (RTOG) protocol 90-05, 38 of whom had recurrent primary brain tumors (median prior dose 60 Gy), and 64 of whom had recurrent brain metastases (median prior dose 30 Gy) < or = 40 mm in maximum diameter. Unacceptable toxicity was defined as irreversible Grade 3, any Grade 4, or Grade 5 central nervous system (CNS) toxicity according to the RTOG CNS criteria, occurring in > 20% of patients per treatment arm within 3 months of radiosurgery.

RESULTS

Patients were initially entered onto one of three treatment arms according to the maximum diameter of the recurrent lesion. Twelve to 22 patients were entered on each arm. The dose levels were: arm 1, < or = 20 mm, 18 Gy; arm 2, 21-30 mm, 15 Gy; and arm 3, 31-40 mm, 12 Gy. Subsequently, doses were escalated as follows: arm 4, < or = 20mm, 21 Gy; arm 5, 21-30 mm 18 Gy; and arm 6, 31-40 mm, 15 Gy. Unacceptable acute toxicity secondary to cerebral edema occurred in 0, 7 and 5% of patients on Arms 1, 2 and 3, respectively, and in no patients on arms 4, 5, or 6. Multivariate analysis revealed that tumor volume > or = 8200 mm(3) and a ratio of maximum dose to prescription dose (MD/PD) > or = 2 were significantly associated unacceptable toxicity. Of 15 patients with both tumor volume > or = 8200 mm(3) and MD/PD > or = 2, unacceptable toxicity occurred in 2 of 4 treated with a single isocenter and 1 of 11 treated with multiple isocenters. Subsequently, operation for symptomatic radionecrosis was required in 6% of patients.

CONCLUSION

We found that the incidence of acute toxicity was acceptable at 0-7% in patients with recurrent, previously irradiated primary brain tumors or brain metastases < or = 40 mm in maximum diameter treated according to the protocol described.

Protochlorophyllide reductase in photosynthetic prokaryotes and its role in chlorophyll synthesis

1. DNA sequences hybridizing with the wheat protochlorophyllide reductase gene have been detected during genomic Southern blots of various cyanobacterial DNA samples. No such hybridization was observed with DNA from photosynthetic bacteria. 2. A fragment amplified from Phormidium laminosum DNA has been characterized and shown to be 73% similar to the corresponding wheat sequence. At the protein level the similarity is 91%. When used as a probe for Southern blotting the Phormidium DNA fragment confirmed the authenticity of some of the original signals obtained with the wheat probe. 3. Peptides of molecular mass 36, 30 and 60 kDa are immunodetected by a wheat reductase antibody during Western blotting of Phormidium preparations. These are purported to correspond to the cyanobacterial mature reductase protein, a stable proteolytic fragment and soluble dimeric forms of the latter respectively. 4. Adaptation of Phormidium to growth in red light (delta > 670 nm) or darkness led to no significant changes in the total level of immunodetected peptides or protochlorophyllide within the cells. 5. The specific activity of the reductase in Phormidium membranes has been tentatively estimated as 0.5 unit/mg of protein, a value comparable with that found in preparations from mature chloroplasts of higher plants.

Double-nested polymerase chain reaction for detection of caprine arthritis-encephalitis virus proviral DNA in blood, milk, and tissues of infected goats

A nested polymerase chain reaction (PCR) for detecting proviral DNA of caprine arthritis-encephalitis virus (CAEV) in biological samples was developed. Primers for both gag and pol sequences of the CAEV genome were included in a single tube for simultaneous amplification ('double' PCR), and the resulting bands were resolved visually in ethidium bromide-stained agarose gels. Internal gag and pol probes were used to verify the identity of the amplified products by non-radioactive Southern hybridization. Final confirmation of the identity of representative PCR bands was provided by DNA sequence analysis. A comparison between the PCR and an antibody ELISA (with recombinant CAEV p28 as target) using 141 caprine blood samples indicated very strong agreement between the two assays (kappa = 0.912). Four of 7 goats with indeterminate ELISA results were PCR-positive as were 5 of 40 (12.5%) seronegative goats, most probably indicating delayed seroconversion. Eleven of 27 goats (41%) PCR-positive on blood had detectable CAEV proviral DNA in milk. Proviral DNA was also detected in lung, mesenteric lymph node, bone marrow, synovial membrane, and mammary gland of a seropositive, clinically affected goat, but not in equivalent tissues of a healthy seronegative goat.

Reproductive performance in high producing dairy cows treated with recombinant bovine somatotropin

The reproductive performance of 156 cows treated with recombinant bST for two consecutive lactations was assessed as part of a target animal safety study conducted in the San Joaquín Valley of central California. Daily intramuscular administration of 17.2, 51.6, and 86 mg of bST per cow started at d 70 postpartum and ended at dry-off or 305 d postpartum. The AI did not begin until d 70 postpartum. During the first lactation study, multiparous cows treated with bST had significantly decreased pregnancy rates, increased behavioral anestrus, and increased anestrus confirmed by palpation. Treated primiparous cows in first lactation had shorter mean days to first standing estrus. In the second lactation study, cows treated with bST had an increased rate of delayed uterine involution, cystic ovarian condition, behavioral anestrus, and anestrus confirmed by palpation. Progeny from the first lactation cows were evaluated for rates of growth, morbidity, mortality, and for reproductive performance; no difference was detected between the progeny from different groups.

Interval from calving to conception in high producing dairy cows treated with recombinant bovine somatotropin

Intervals from calving to conception in cows treated for two lactations with recombinant bST were ascertained using survival analysis methods. Daily intramuscular administration of placebo, 17.2, 51.6, or 86 mg of bST per cow started at d 70 postpartum and ended at culling or drying off. Breeding began at d 70 postpartum. Multiparous cows treated during the first lactation had significantly longer intervals from calving to conception. Cows treated during the previous lactation, but not during the second lactation, had significantly shorter intervals from calving to conception. Cox proportional hazards regression analysis was used with adjustment for the confounding effect of serum metabolites, milk production, energy balance, and body condition.

DNA deoxyribophosphodiesterase and an activity that cleaves DNA containing thymine glycol adducts in Deinococcus radiodurans

Deinococcus radiodurans is the most radioresistant bacterium discovered to date. Recently it has been demonstrated that this organism contains the DNA repair enzyme uracil-DNA glycosylase and an apurinic/apyrimidinic (AP) endonuclease that may function as part of a DNA base excision repair pathway. We demonstrate here that a DNA deoxyribophosphodiesterase activity that acts on incised AP sites in DNA to remove deoxyribose-phosphate groups is found in lysates prepared from D. radiodurans cells. The partially purified activity was found to be smaller in size than the E. coli dRpase activity, with an estimated molecular weight of 25-30 kDa. In addition, an activity that recognizes and cleaves DNA containing thymine glycols was also detected, with a molecular weight of approximately 30 kDa. This enzyme may be analogous to the thymine glycol glycosylase/AP lyase endonuclease III of E. coli.

Experimental reproduction of bovine fetal Neospora infection and death with a bovine Neospora isolate

Studies were conducted to determine the pathogenic potential of the recently isolated bovine Neospora protozoa (BPA-1) for the bovine fetus. Cows chosen for study had Neospora titers < 160 using an indirect immunofluorescent antibody (IFA) test. Four experimental groups were studied. In group 1, 2 fetuses were inoculated in utero at 118 days gestation with culture-derived Neospora tachyzoites. A pregnant control cow was housed in the same pen, observed daily and screened serologically for evidence of exposure to Neospora. In group 2, 2 cows were infected with Neospora tachyzoites at 138 or 161 days gestation, and 1 control cow was given uninfected cell culture suspension simultaneously at 154 days gestation. Groups 3 (85 days gestation) and 4 (120 days gestation) each consisted of 2 cows infected with Neospora tachyzoites and 1 control cow given uninfected material at the same stage of gestation. Dead fetuses were surgically removed from the infected cows in group 1 on postinfection day (PID) 17. The histopathology was compatible with protozoal fetal infection, and protozoa were identified by immunohistochemistry. Viable fetuses were removed surgically from cows in group 2 on PID 28-30. The histopathology was compatible with protozoal fetal infection, protozoa were identified by immunoperoxidase techniques, and Neospora tachyzoites were reisolated in vitro from tissues of the 2 infected fetuses. In groups 3 and 4, the control fetus and 1 infected fetus were removed surgically between PID 26 and PID 33. The remaining infected cows were observed until fetal death or abortion occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered RNA turnover in carcinogenesis. The diagnostic potential of modified base excretion

Excretion of urinary modified nucleosides is frequently elevated in patients with oncogenic disease. Increases of urinary pseudouridine excretion are now demonstrated in patients with a variety of brain tumors. The potential use of urinary modified base excretion as a cancer marker is discussed and possible sources of the elevated nucleosides are detailed. The specific steps in RNA metabolism that result in increased levels of RNA nucleoside excretion are poorly understood. This knowledge will be necessary to understand the molecular mechanism and the clinical significance of urinary nucleoside excretion in treatment and diagnosis of oncogenic disease.

Pregnancy incidence in high producing dairy cows treated with recombinant bovine somatotropin

Reproductive performance in cows exposed for two lactations to recombinant bST was measured using unconditional logistic regression. Intramuscular administration of 17.2, 51.6, and 86 mg of recombinant bST/d per cow started at d 70 postpartum and ended at dry-off or 305 d postpartum. Performance was measured as the cumulative incidence of cows becoming pregnant by 305 d post-partum. Within each parity group, cows treated with bST had higher total milk yield. During the first study lactation, the log odds of a cow becoming pregnant decreased linearly as dose increased, following adjustment for serum cholesterol, blood urea N, average daily milk yield, peak milk yield, net energy balance, and body condition score. However, differences in pregnancy incidence between treated and untreated cows were statistically significant only at the higher dose categories, the 51.6 and 86.0 mg of recombinant bST per cow. During the second study lactation, pregnancy rates were similar to those in the first lactation; rates reduced as recombinant bST dose increased. The singular exception was for cows exposed to recombinant bST during the previous lactation but not during the second. In the latter group, previously treated cows had higher pregnancy incidence than did the controls.

Microinjection of bovine embryos with a foreign gene and its detection at the blastocyst stage

This study was designed to measure the survival and development of pronuclear stage bovine zygotes after microinjection with DNA and either culture in vitro or incubation in the sheep oviduct and to determine the percentage of embryos that retain exogenous DNA at the blastocyst stage. In vitro matured and fertilized oocytes were examined for pronuclear development 18 to 20 h after coincubation with sperm. An ovine somatotropin gene construct was microinjected into ova with visible pronuclei. Microinjected ova and unmanipulated ova from the same in vitro derived pool were cocultured with oviductal epithelial cells or incubated in the sheep oviduct and cocultured, respectively, for 7 d. Blastocysts were subjected to polymerase chain reaction analysis for detection of exogenous DNA. The percentage of cleaved embryos that formed blastocysts was similar for microinjected and unmanipulated cultured ova. The percentage of blastocysts recovered from the sheep oviduct that hatched was higher than for blastocysts that developed in coculture. Fourteen of 26 (54%) blastocysts that developed from microinjected ova were positive for the exogenous DNA by polymerase chain reaction. The implications are discussed for polymerase chain reaction detection of the exogenous gene construct in a relatively high proportion of microinjected blastocysts.

Cohort study of natural transmission and two methods for control of caprine arthritis-encephalitis virus infection in goats on a California dairy

A prospective observational cohort study of 361 dairy goat kids was conducted to compare 2 methods of controlling caprine arthritis-encephalitis virus infection under commercial dairy conditions. To compare effectiveness of feeding kids pasteurized milk vs serologic testing and segregation in addition to pasteurized milk feeding, goats were monitored up to the age of 30 months by use of monthly agar gel immunodiffusion testing. Survival analysis methods were used to determine whether age at seroconversion differed between the 2 groups. Significantly lower rates of seroconversion were observed in the segregated group (P < 0.001), compared with the nonsegregated group. Of 193 goats in the pasteurized milk-only group, 146 (75.6%) seroconverted within the 30-month study period, whereas infection was detected in 39 (23.2%) of 168 goats in the test/segregated group. Nonsegregated goats were 3.37 times more likely to seroconvert by 24 months of age, and 70.3% of seroconversions by 24 months of age could be attributed to nonsegregation. For age-specific intervals beyond 180 days of age, 70 to 100% of seroconversions could be attributed to lack of segregation. Cohort life tables for age at seroconversion were reported for each group. Type of colostrum fed, sex, and weaning group (season) were not significantly associated with age at seroconversion. Saanen goats had lower age-specific risk of seroconversion in the nonsegregated group alone and overall. Non-Saanen goats wee 1.5 times more likely to seroconvert than were Saanen goats, when adjusted for a possible confounding effect of weaning group. Results indicate that pasteurized milk feeding and routine test and segregation would be a substantially more effective means of control of the disease in dairy goat herds than would pasteurized milk feeding alone.

Risk factors associated with the incidence of seroconversion to caprine arthritis-encephalitis virus in goats on California dairies

Incidence of seroconversion to caprine arthritis-encephalitis virus (CAEV) was determined for 1,194 goats on 11 dairies, using 2 repeated annual herd tests for CAEV. Current life table methods were used to compare age-specific incidence of seroconversion for pasteurized milk-raised and unpasteurized milk-raised goats. Logistic regression models were used to determine the risk factors associated with CAEV seroconversion, and to estimate odds ratios for seroconversion for various factor levels. Goats raised by unpasteurized milk-feeding methods were 2.5 to 6.7 times more likely to seroconvert than were goats raised by pasteurized milk-feeding methods, depending on the method of comparison. Similarly, 61.6 to 85.0% of seroconversions in yearling goats possibly were attributable to unpasteurized milk feeding. Among yearling goats, CAEV seroconversion was associated with feeding method, breed, and source of goat (herd of origin) when the effect of dairy was considered. In addition to the 6.7 times greater risk of seroconversion for unpasteurized milk-raised goats, yearling goats of the Saanen and Toggenburg breeds were 2.2 and 3.3 times, respectively, more likely to seroconvert than were Alpine yearling goats. Yearling goats purchased from another source were less likely to seroconvert than were yearlings raised on the dairy where they were studied. Among goats > 1 year old, age was associated with risk of seroconversion. Goats that were 3 years old or were > or = 4 years old were 1.7 and 3.2 times, respectively, more likely to seroconvert than were 2-year-old goats, when adjusted for effect of dairy. The effects of dairy were significant (P < or = 0.001) in yearling and older goats.

Risk factors associated with caprine arthritis-encephalitis virus infection in goats on California dairies

Log-linear methodology was used to examine relations among caprine arthritis-encephalitis virus (CAEV) seroreactivity and host/management factors in a cross-sectional study of 2,826 goats on 13 California dairies. The CAEV serologic status was associated with age and feeding method (pasteurized/unpasteurized milk), but not with breed. Data from a prevalence survey of 321 goats from 2 additional dairies demonstrated very good fit of the selected log-linear model (P = 1.00), indicating that the model was very appropriate to describe the relations. Odds of seropositivity and odds ratios were generated by use of a logit model derived from the log-linear model. Goats raised by the unpasteurized feeding method were estimated to have been 3.3 times more likely to be CAEV-seropositive than goats fed by the pasteurized method, when adjusted for the effects of age. Goats aged 2, 3, 4, and 5 or greater years were estimated to have been 1.7, 2.6, 4.5, and 5.7 times, respectively, more likely to be CAEV-seropositive than were yearling goats when ratios were adjusted for pasteurization status. Breed, gender, and herd of origin were not associated with CAEV seroreactivity when the effects of other factors were considered. Estimated odds of CAEV seroreactivity and the associated odds ratios for combinations of factor levels are reported. In this study, the magnitude and direction of the associations among CAEV serologic status, age, and pasteurized feeding methods were demonstrated.

Production of sheep-goat chimeras by inner cell mass transplantation

Embryos were surgically flushed from goats and sheep on d 6 and 7, respectively, following the first day of estrus (d 0). After enzymatic removal of the zonae pellucidae, inner cell masses were isolated from caprine blastocysts by immunosurgery. The intact inner cell masses were injected into ovine blastocysts with the aid of a micromanipulator. Twenty-two manipulated blastocysts were surgically transferred into 12 ovine recipients. Nine ewes gave birth to a total of 13 young (59% embryo survival). Ten were classified by serum electrophoretic assays or karyotypes as lambs, one as a kid, and two as interspecific chimeras.