Comparison of reproductive performance of primiparous dairy cattle following revaccination with either modified-live or killed multivalent viral vaccines in early lactation.

The objective of this randomized clinical trial was to compare the effect of revaccination in primiparous dairy cows with modified live viral (MLV) or killed viral (KV) vaccines containing bovine viral diarrhea virus (BVDV) and bovine herpesvirus-1 (BoHV-1) on (1) pregnancy rate following estrus synchronization-timed artificial insemination (TAI), (2) serum progesterone concentrations, and (3) serum neutralizing antibody titers at revaccination and at TAI. Primiparous dairy cows (n=692) that had been previously vaccinated with 4 doses of MLV vaccine as calves or heifers were randomized to receive either an MLV or a KV vaccine between 21 and 28 d in milk and 17 d before initiation of a double-Ovsynch-TAI protocol. Serum was collected within the double-Ovsynch protocol for determination of progesterone concentrations, and at vaccination and TAI for serum neutralizing antibody titers. Ultrasound pregnancy determinations were made at 30 and 60 d after TAI. No differences in pregnancy rates were observed between cows receiving MLV vaccine (44%; n=326) or KV vaccine (43%; n=336). No differences were observed in serum progesterone concentrations during a double-Ovsynch-TAI protocol between cows receiving MLV and KV vaccines. No differences were observed in BVDV 1 or BVDV 2 antibody titers at vaccination and TAI between cows receiving MLV or KV vaccine; however, BoHV-1 antibody titers were greater at TAI in cows receiving KV vaccine. Overall response to vaccination-defined as the percent of all individual cows that had any detectable increase in antibody titer from vaccination to TAI-was 39% for BVDV 1, 45% for BVDV 2, and 61% for BoHV-1. In this research, use of an MLV vaccine did not impede reproduction when revaccination was performed between 21 and 28 DIM and just before enrollment in an estrus synchronization-TAI program in primiparous dairy cows; however, response to vaccination as defined by increases in virus-specific antibody titers could be considered less than ideal for this population of cattle.

Exposure of neonatal rats to anti-androgens induces penile mal-developments and infertility comparable to those induced by oestrogens.

We previously reported that oestrogen exposure in neonatal rats induced permanent infertility and malformed penis characterized by fat accumulation, which replaced most of the smooth muscle cells and cavernous spaces in the body of the penis, structures essential for erection. The objective of this study was to determine if reduced androgen production/action in the neonatal period, in the absence of exogenous oestrogen exposure, induces penile deformities similar to those caused by oestrogen. Male rats were treated from postnatal days 1-6 with GnRH antagonist antide (A, 10 mg/kg) or androgen receptor (AR) antagonist flutamide (F, 50 mg/kg) or F + A, with or without AR agonist dihydrotestosterone (DHT, 20 mg/kg). For comparison, pups received diethylstilbestrol (DES, 0.1 mg/kg), with or without DHT. Tissues were collected at ages 7 and 12 days and at adulthood. Flutamide alone decreased penile length and weight significantly (p < 0.05), but it caused neither fat accumulation, nor affected fertility (80% vs. 87% in controls). Antide alone reduced penile length and weight significantly, and induced fat accumulation in 4/11 rats and infertility in 13/14 rats. Conversely, all 11 F + A-treated rats, similar to all nine DES-treated rats, had fat accumulation and loss of smooth muscle cells and cavernous spaces in the body of the penis and were infertile. In addition, reductions in penile length and weight were higher than in rats treated with F or A alone. DHT co-administration mitigated penile deformities in the DES group, but did not in the F + A group. Testicular testosterone was reduced by 70-95% at 7 or 12 days of age in all treated groups, except in the F group, which had threefold higher testosterone than controls. Collectively, data unequivocally show that reduced androgen production/action in the neonatal period, in the absence of oestrogen exposure, induces permanent infertility and malformed penis similar to that caused by oestrogen.

Estrogen-induced developmental disorders of the rat penis involve both estrogen receptor (ESR)- and androgen receptor (AR)-mediated pathways.

This study tested the hypothesis that the estrogen receptor (ESR) pathway, androgen receptor (AR) pathway, or both mediate estrogen-induced developmental penile disorders. Rat pups received diethylstilbestrol (DES), with or without the ESR antagonist ICI 182,780 (ICI) or the AR agonist dihydrotestosterone (DHT) or testosterone (T), from Postnatal Days 1 to 6. Testicular T concentration, penile morphology and morphometry, and/or fertility was determined at age 7, 28, or 150 days. DES treatment alone caused 90% reduction in the neonatal intratesticular T surge; this reduction was prevented by ICI coadministration, but not by DHT or T coadministration. Unlike the T surge, coadministration of ICI and coadministration of DHT or T mitigated penile deformities and loss of fertility. Generally, ICI, DHT, or T treatment alone did not alter penile morphology; however, fertility was 20% that of controls in ICI-treated rats vs. 70%-90% in DHT- or T-treated rats. The lower fertility in the rats treated with ICI alone could be due to altered sexual behavior, as these males did not deposit vaginal plugs. In conclusion, observations that both an ESR antagonist and AR agonists prevent penile deformities and infertility suggest that both pathways are involved in estrogen-induced penile disorders. Observations that coadministration of ICI, but not DHT or T, prevents the DES-induced reduction in the neonatal T surge suggest that, although ICI exerts its mitigating effect both at the level of Leydig cells and penile stromal cells, DHT and T do so only at the level of stromal cells.

The effects of chronic mercuric chloride ingestion in female Sprague-Dawley rats on fertility and reproduction.

Thirty-days-old female rats were chronically exposed, for 60 days, to 1or 2mg/kg/day of mercuric chloride or an equivalent volume of water, via gavage. At 90 days of age they were mated with unexposed males. At approximately day 13 of gestation necropsies were performed on the females. Data were collected on the number of implantations and non-viable implantations in the uterus. No physical signs of Hg intoxication were seen except in weight gain. There were significantly fewer implantations in the high HgCl2 group, with significantly more non-viable implantations in the low and high HgCl2 groups, compared to controls. Lower levels of progesterone and higher levels of pituitary luteinizing hormone (LH) were found in the high HgCl2 group compared to controls, whereas pituitary follicle stimulating hormone levels (FSH), while not significant, showed a dose-response relationship to HgCl2 levels. No difference was found in the number of corpora lutea. The experiment indicated low level chronic ingestion of mercuric chloride, in female rats, while not effecting ovulation, produced disruption of implantation and fetal viability. Lower progesterone levels, higher LH, and possibly FSH levels, indicate that mercuric chloride may have a disruptive effect in the corpora lutea which manifests itself after ovulation.

Estrogen receptor alpha mediates estrogen-inducible abnormalities in the developing penis.

Previously, we reported an association between estrogen receptor-alpha (ERalpha) upregulation and detrimental effects of neonatal diethylstilbestrol (DES) exposure in the rat penis. The objective of this study was to employ the ERalpha knockout (ERalphaKO) mouse model to test the hypothesis that ERalpha mediates DES effects in the developing penis. ERalphaKO and wild-type C57BL/6 mice received oil or DES at a dose of 0.2 microg/pup per day (0.1 mg/kg) on alternate days from postnatal days 2 to 12. Fertility was tested at 80-240 days of age and tissues were examined at 96-255 days of age. DES caused malformation of the os penis, significant reductions in penile length, diameter, and weight, accumulation of fat cells in the corpora cavernosa penis, and significant reductions in weight of the bulbospongiosus and levator ani muscles in wild-type mice. Conversely, ERalphaKO mice treated with DES developed none of the above abnormalities. While nine out of ten male mice sired pups in the wild-type/control group, none did in the wild-type/DES group. ERalphaKO mice, despite normal penile development, are inherently infertile. Both plasma and intratesticular testosterone levels were unaltered in the DES-treated wild-type or DES-treated ERalphaKO mice when compared with controls, although testosterone concentration was much higher in the ERalphaKO mice. Hence, the resistance of ERalphaKO mice to developing penile abnormalities provides unequivocal evidence of an obligatory role for ERalpha in mediating the harmful effects of neonatal DES exposure in the developing penis.

Role of estrogen in induction of penile dysmorphogenesis: a review.

In this review, we report permanent dysmorphogenesis of the penis and loss of fertility in adult rats treated neonatally with estrogen. Specifically, we report replacement of smooth muscle cells and cavernous spaces by fat cells in the corpus cavernosum penis, but not in the adjoining corpus spongiosum. Induction of these novel, region-specific phenotypes is dose-dependent, requires a critical window of exposure and associated with decreased testosterone and up-regulation of estrogen receptor alpha (ER alpha). The resistance of ER alpha knockout mice to develop these abnormalities implies an unequivocal role for ER alpha in mediating maldevelopment of the penis. Additionally, the prevention of estrogen-inducible penile abnormalities by ER antagonist ICI 182 780 implies that a functional ER-mediated pathway is essential for inducing penile abnormalities. Likewise, the ability of testosterone or dihydrotestosterone to negate these abnormalities suggests a role for an androgen receptor (AR)-mediated pathway. Taken together, these observations led us to hypothesize that neonatal estrogen exposure, via an ER-mediated pathway (direct action) or an AR-mediated pathway (indirect action through decreased testosterone) or both pathways, up-regulates ER alpha expression in stromal cells of the penis, which are then reprogrammed such that their differentiation into smooth muscle cells is inhibited and their differentiation into adipocytes is stimulated.

Estrogen-induced abnormal accumulation of fat cells in the rat penis and associated loss of fertility depends upon estrogen exposure during critical period of penile development.

We previously reported that diethylstilbestrol (DES) or estradiol valerate (EV) exposure at a dose of 0.10-0.12 mg/kg, or higher, per day, on alternate days, from postnatal days 2-12, resulted in abnormal penis development and infertility (H. O. Goyal et al., 2005, J. Androl. 26, 32-43). The objective of this study was to identify a critical developmental period(s) during which EV exposure results in the observed penile abnormalities. Male pups received EV at a dose of 0.10-0.12 mg/kg on postnatal day(s) 1, 1-3, 4-6, 1-6, 7-12, 13-18, 19-24, or 25-30. Fertility was tested at 102-115 days of age and tissues were examined at 117-137 days. Both penile morphology and fertility were unaltered in rats treated with EV after 12 days of age. Conversely, except in rats treated on postnatal day 1 only, none of the males treated prior to 12 days of age sired pups, and all had abnormal penises, including varying degrees of abnormal accumulation of fat cells and loss of cavernous spaces and smooth muscle cells in the corpora cavernosa penis, which were maximal in the 1-6-day group. Also, the preputial sheath was partially released or its release was delayed, and the weight of the bulbospongiosus muscle was significantly reduced. Plasma testosterone (T) in the 1-6- and 4-6-day groups and intratesticular T in the 4-6-day group were significantly lower. The testosterone surge, characteristic of controls in the first week of life, was suppressed in the 1-3-day group. Estrogen receptor alpha mRNA expression was enhanced in the body of the penis in the 1-3-day group, but not in the 13-18-day group. Hence, EV exposure prior to 12 days of age (as short as 1-3 days postnatal), but not after 12 days of age, results in long-term abnormal penile morphology, characterized by abnormal accumulation of fat cells in the corpora cavernosa penis and, consequently, loss of fertility.

Exposure of neonatal male rats to estrogen induces abnormal morphology of the penis and loss of fertility.

The research objectives are to determine whether estrogen-induced infertility is associated with abnormal morphology of the penis and if morphological alterations can be reversed by testosterone (T). Male pups received diethylstilbestrol (DES) on alternate days from postnatal days 2 to 12. They received T or empty implants at 180 days, were tested for fertility at 188 days, and terminated at 200 days. While 5/7 control males sired pups, only 1/6 did in the DES group, and 0/8 in the DES plus T group. In addition to reductions in penile length and weight, the novel structural change induced by DES, and not reversed by T, was a replacement of cavernous spaces by fat cells in the penis body. Hence, T substitution for 8 days at adulthood did not reverse infertility in rats treated neonatally with DES and provided evidence that infertility probably resulted from absence of cavernous spaces and/or accumulation of fat cells in the penis body.

Abnormal morphology of the penis in male rats exposed neonatally to diethylstilbestrol is associated with altered profile of estrogen receptor-alpha protein, but not of androgen receptor protein: a developmental and immunocytochemical study.

Objectives of the study were to determine developmental changes in morphology and expression of androgen receptor (AR) and estrogen receptor (ER)alpha in the body of the rat penis exposed neonatally to diethylstilbestrol (DES). Male pups received DES at a dose of 10 microg per rat on alternate days from Postnatal Day 2 to Postnatal Day 12. Controls received olive oil vehicle only. Tissue samples were collected on Days 18 (prepuberty), 41 (puberty), and 120 (adult) of age. DES-induced abnormalities were evident at 18 days of age and included smaller, lighter, and thinner penis, loss of cavernous spaces and associated smooth muscle cells, and increased deposition of fat cells in the corpora cavernosa penis. Fat cells virtually filled the entire area of the corpora cavernosa at puberty and adulthood. Plasma testosterone (T) was reduced to an undetectable level, while LH was unaltered in all treated groups. AR-positive cells were ubiquitous and their profile (incidence and staining intensity) did not differ between control and treated rats of the respective age groups. Conversely, ERalpha-positive cells were limited to the stroma of corpus spongiosus in all age groups of both control and treated rats, but the expression in treated rats at 18 days was up-regulated in stromal cells of corpora cavernosa, coincident with the presence of morphological abnormalities. Hence, this study reports for the first time DES-induced developmental, morphological abnormalities in the body of the penis and suggests that these abnormalities may have resulted from decreased T and/or overexpression of ERalpha.

Influence of estradiol, progesterone, and nutrition on concentrations of gonadotropins and GnRH receptors, and abundance of mRNA for GnRH receptors and gonadotropin subunits in pituitary glands of beef cows.

Nutritionally induced anovulatory cows (n = 28) were used to determine the effect of steroids on regulation of synthesis and secretion of gonadotropins. Anovulatory cows were ovariectomized and received intravaginal inserts containing estradiol (E2), progesterone (P4), E2 and P4 (E2P4), or a sham intravaginal insert (C) for 7 d. Concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were quantified in serum and E2 and P4 were quantified in plasma. Cows were exsanguinated within 1 to 2 h after removal of intravaginal inserts and pituitary glands were collected and stored at -80 degrees C until messenger ribonucleic acid (mRNA) for gonadotropin-releasing hormone receptor (GnRH-R) and gonadotropin subunits, pituitary content of GnRH-R, and LH and FSH were quantified. Pituitary glands from five proestrous cows were harvested to compare gonadotropin characteristics between ovariectomized, anovulatory cows and intact cows. Plasma concentrations of E2 were greater (P < 0.05) in E2-treated cows than in sham-treated cows. Concentrations of P4 were greater (P < 0.05) in cows treated with P4 than in sham-treated cows. Mean serum concentrations of LH and FSH were not significantly influenced by steroid treatments. However, frequency of LH pulses of ovariectomized, nutritionally induced anovulatory cows was increased (P < 0.05) by treatment with E2 and amplitude of LH pulses was greater (P < 0.05) in cows treated with E2 or P4 than in cows treated with E2P4 or sham-treated. Quantity of mRNA for LHbeta in the pituitary gland was greater when cows were treated with P4. Concentrations of LH in the pituitary gland were not affected by steroid treatments; however, pituitary concentrations of FSH were less (P < 0.1) in E2 cows than in sham-treated cows. The number of GnRH-R was increased (P < 0.05) in cows treated with E2, but P4 treatment did not influence the number of GnRH-R. Abundance of mRNA for GnRH-R, common alpha-subunit, and FSHbeta were not affected by treatments. Pituitary concentrations of LH were greater (P < 0.05) and concentrations of FSH were less (P < 0.05) in proestrous cows than in ovariectomized, anovulatory cows treated with or without steroids. Abundance of mRNA for GnRH-R, common alpha-subunit, LHbeta and FSHbeta were similar for proestrous and anovulatory cows. We conclude that treatment of nutritionally induced anovulatory cows with progesterone and estradiol may cause pulsatile secretion of LH.

Neonatal estrogen exposure of male rats alters reproductive functions at adulthood.

The effects of neonatal exposure to different doses of diethylstilbestrol (DES) on the reproductive functions of male rats at adulthood were evaluated. Sprague-Dawley rats (5-8/group) received sc injections of 25 microl olive oil containing DES (Sigma Chemical Co., St. Louis, MO) at a dose of 10 microg, 1 microg, 100 ng, 10 ng, or 1 ng per rat on alternate days from Postnatal Days 2-12. Control animals received olive oil only. All animals were allowed to develop until 83-91 days of age; however, when they were 70 to 80 days old, four male rats each from the 10 microg, 1 microg, 100 ng, and control groups were cohabited with untreated 60- to 70-day-old females (1:1) for 12 days. At the end of cohabitation, both mated and unmated male rats were weighed, and blood and tissue samples were collected and processed. Results revealed that although sperm motility patterns and sperm morphology were adversely affected in the 10- microg group, other reproductive parameters, including 1). daily sperm production (DSP)/testis; 2). absolute and relative weights of the testis, epididymis, and seminal vesicle; and 3). sperm numbers in both regions of the epididymis declined significantly in a dose-dependent manner in the 10- and 1- microg groups. Conversely, in the <1- microg groups, none of these parameters (except DSP/testis and weight of the epididymis in the 100-ng group, and sperm numbers in the epididymis of the 100- and 10-ng groups) was different from controls. Generally, plasma testosterone levels decreased in the 10- and 1- microg groups, FSH level increased in the 10-microg group, and prolactin and LH levels were unaltered. In the fertility study, although each male in the 1-microg, 100-ng, and control groups produced a copulatory plug and impregnated a female, none could do so in the 10-microg group. The mean number of pups per litter was reduced to eight in the 1-microg group, in contrast to 15 each in the 100-ng and control groups. In conclusion, exposure of neonatal male rats to DES altered sperm motility patterns, sperm fertility (as evident from the reduced number of pups in the 1-microg group), and sexual behavior (as evident from the absence of copulatory plugs in the 10-microg group) and reduced weights of reproductive organs, DSP/testis, and sperm numbers in the epididymis. Whether these alterations/reductions persist in older rats (6-8 mo of age) is under investigation.

Luteal and clinical response following administration of dinoprost tromethamine or cloprostenol at standard intramuscular sites or at the lumbosacral acupuncture point in mares.

OBJECTIVE: To determine whether administration of a microdose of prostaglandin at the BAI HUI acupuncture point offers any advantage over IM injections for luteolysis, ovulatory interval, or systemic response in mares. ANIMALS: 17 mature cycling mares, 3 to 20 years of age and weighing 400 to 500 kg. PROCEDURE: Conventional and microdoses of the prostaglandin dinoprost tromethamine (PGF2alpha), the analogue cloprostenol, or sterile water (control) were administered to mares in 7 treatment groups. Treatments were assigned by dose, administration site (semimembranosus, semitendinosus, or lumbosacral region), and treatment type (PGF2alpha, analogue, or sterile water). Mares were observed for ovulatory interval and systemic response to treatment, including heart, and respiratory rates, rectal temperature, and sweat score. Plasma progesterone concentrations were also determined at the time of treatment and at 24-hour intervals for 96 hours following treatment. RESULTS: Ovulatory interval was shortened and progesterone concentrations decreased in prostaglandin-treated mares, compared with control mares, regardless of dose or treatment site. However, no differences in ovulatory interval were observed among prostaglandin-treated mares. Mares treated with conventional doses of PGF2alpha had greater systemic responses than mares treated with microdoses of PGF2alpha or sterile water. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of prostaglandins at the BAI HUI acupuncture point does not appear to offer any advantage over administration at standard IM injection sites for induction of luteolysis or to shorten the ovulatory interval. However, administration of a microdose of the analogue cloprostenol was effective at inducing luteolysis and shortening ovulatory interval regardless of administration site.

Expression of insulin-like growth factor binding protein (IGFBP)-3, and the effects of IGFBP-2 and -3 in the bovine corpus luteum.

The present study was conducted to gain insight into the insulin-like growth factor (IGF) system in the bovine corpus luteum (CL). Specific aims were to measure the levels of IGF binding protein-3 (IGFBP-3) and RNA encoding IGFBP-3 in the CL throughout diestrus, and to investigate the effects of IGFBP-2 and -3 on IGF-I-stimulated progesterone (P4) production and IGF-I-receptor binding. Bovine CL were collected from a local abattoir and classified according to stage of diestrus based on anatomical characteristics. Corpora lutea from early, mid and late diestrus were each analyzed for the presence of IGFBP-3 by ligand blot analysis, and for RNA encoding IGFBP-3 by Northern blot analysis. Dissociated cells from mid-cycle CL were treated with IGF-I, IGFBP-2 or -3, or a combination of IGF-I and IGFBP-2 or -3. The effect of IGFBP-2 and IGFBP-3 on [(125)I] IGF-I binding to its receptor on CL plasma membranes also was investigated. IGFBP-3 protein and RNA expression were higher in early CL, compared to mid or late CL (p < 0.05). IGF-I stimulated P4 production in a dose-dependant manner (p < 0.05). IGFBP-2 and -3 blocked the stimulatory effect of IGF-I on P4 production (p < 0.05). Both IGFBP-2 and -3 inhibited [(125)I]-IGF-I binding to its receptor in a dose-dependant manner. These results demonstrate that IGFBP-3 protein and RNA are expressed predominantly during early diestrus in the bovine CL. Moreover, both IGFBP-2 and -3 can modulate IGF-I actions in the CL by interfering with binding of IGF-I to its receptor.

Diethylstilbestrol-treated adult rats with altered epididymal sperm numbers and sperm motility parameters, but without alterations in sperm production and sperm morphology.

In this study, we characterized estrogenic effects of diethylstilbestrol (DES) on reproductive parameters in male rats to identify a minimal dose level that alters epididymal and sperm functions but has little or no effect on sperm production and/or spermatogenesis. Adult rats (five animals/group) received s.c. injections of 0.2 ml of corn oil containing DES at a rate of 1.0 mg, 200 microg, 40 microg, 8 microg, 1.6 microg, or 320 ng x rat(-1) x day(-1) for 12 days. The control group received corn oil only. DES effects were similar in the 8-microg group and higher dose groups and included significant (P < or = 0.05) reductions in 1) absolute and relative weights of the head and body of the epididymis (EP), tail of the EP, and seminal vesicle, 2) numbers of sperm in both regions of the EP, and 3) motility characteristics in sperm collected from the tail of the EP. Conversely, no significant changes were observed in relative testis weight, daily sperm production, spermatogenesis, seminiferous epithelial height in stage VII, and sperm morphology. All of the above parameters in the 1.6-microg group (except seminal vesicle weight) and 320-ng group were comparable to those of controls. Plasma testosterone (T) level was reduced to an almost undetectable level in the > or = 8-microg groups and to a very low level in the 1.6-microg group (0.35 vs. 2.36 ng/ml in controls or 320-ng group), but LH level was unaltered. In a parallel fertility study, males received DES at a rate of 40, 8, or 1.6 microg x rat(-1) x day(-1) for 12 days prior to and 12 days during cohabitation (1:1) with untreated females. Of the 15 females cohabited with treated males (5 females/dose), none in the 40-microg and 8-microg groups and 1 in the 1.6-microg group formed a copulatory plug and delivered 8 pups, in contrast to 5/5 copulatory plugs and 13-15 pups/litter in the controls. DES at a rate of 8 microg x rat(-1) x day(-1) for 12 days reduced EP weights, sperm numbers in the EP, and sperm motility patterns but caused minimal to no alterations in daily sperm production, spermatogenesis, or sperm morphology. Factors other than T, or in addition to lower T, may be responsible for DES-induced reproductive disorders (despite lower T, sperm contents and sperm motility patterns in the EP were normal in the 1.6-microg group). Deficits in EP sperm functions and/or sexual behavior (as evident from absence of copulatory plugs) probably accounted for reduced fertility in treated males.

Radiographic, biomechanical, and pathologic effects of hemoglobin glutamer-200 in dogs undergoing cemented total hip arthroplasty.

OBJECTIVE: To determine whether use of hemoglobin glutamer-200 (bovine) as a partial blood volume replacement in dogs undergoing cemented total hip replacement caused any deleterious effects on the bone-cement or cement-prosthesis interface, exerted any deleterious effects on body organs, or caused any complications during the anesthetic, immediate recovery, or long-term recovery period. ANIMALS: 9 adult dogs. METHODS: Dogs were anesthetized, and 15% of the blood volume was removed. Simultaneously, lactated Ringer's solution was infused, and 6 dogs were given hemoglobin glutamer (1 g/kg of body weight, IV). Unilateral total hip replacement was performed. Limb use was assessed visually, and force-plate and radiographic evaluations were performed before, and 8 weeks after, surgery. Eight weeks after surgery, dogs were euthanatized, necropsies were performed, and prosthetic component pullout forces were determined. RESULTS: There were no significant differences between treated and control dogs in regard to biomechanical (visual assessment of gait, force-plate analysis, femoral and acetabular component pullout forces) and pathologic evaluations (physical examination, CBC, serum biochemical analyses, necropsy, and histologic evaluations). Radiographic signs of loosening of the femoral component were seen in 4 dogs treated with hemoglobin glutamer. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of hemoglobin glutamer as a blood substitute did not appear to have any deleterious effects in dogs undergoing total hip arthroplasty. The radiographic findings, which were discordant with the biomechanical results, merit further investigation.

Effects of interleukins on secretion of luteinizing hormone from ovine pituitary cells.

OBJECTIVE: To determine whether cytokines of homologous species might mediate the stimulatory effects of endotoxin on release of luteinizing hormone (LH) from pituitary cells. SAMPLE POPULATION: Cells from pituitary glands collected from 8- to 14-month-old wethers. PROCEDURE: Cells from the anterior pituitary gland were cultured in the presence of recombinant ovine or bovine cytokines (interleukin [IL]-1alpha, IL-1beta, and IL-2), tumor necrosis factor-alpha (TNF), and interferon-gamma (IFN-gamma). Luteinizing hormone that was released into the medium was measured. Cells were also cultured with modulators of signal transduction pathways to evaluate the second messenger system used by IL-1 alpha and IL-1beta. RESULTS: Similar to effects of endotoxin, IL-1alpha and IL-1beta stimulated release of LH. Interleukin 2, TNF, and IFN-gamma did not have a detectable effect on release of LH. Stimulation of LH release by IL-1alpha and IL-1beta required activation of voltage-dependent Ca2+ channels and appeared to involve protein kinase C. CONCLUSIONS: IL-1alpha and IL-1beta may mediate the direct stimulatory effect of endotoxin on release of LH in vitro. Interleukin 2, TNF, and IFN-gamma do not have a direct effect on release of LH; therefore, they do not mediate this effect of endotoxin. CLINICAL RELEVANCE: Stressors, including infection, are often associated with reduced fertility. Infection resulting in endotoxin release, production of interleukins, or both, can lead to direct stimulation of LH release from the pituitary gland. Inopportune release of LH via cytokines may interfere with normal pulsatile release of LH, thereby suppressing gonadal function.

Keratinocyte growth factor expression by the bovine corpus luteum.

Communication between cells of the corpus luteum (CL) is thought to be necessary for normal luteal function. Keratinocyte growth factor (KGF) is produced by mesenchymally derived cells in numerous tissues and acts on epithelial cells. In bovine follicles, theca cells produce KGF, which can stimulate granulosa cell proliferation. Whether KGF is produced by ovarian cells after luteinization is unknown. Our objective was to determine whether KGF mRNA and protein were present in bovine luteal tissue, and if so, to determine what type(s) of luteal cells contains KGF. CL (n = 3-4/day) were obtained from specific days throughout diestrus. Presence of KGF mRNA in CL was determined using a porcine KGF anti-sense cRNA probe. Northern analyses of luteal tissue poly(A)+ RNA revealed a single transcript (approximately 2.0 kilobases), the quantity of which did not change throughout diestrus. Western analysis revealed an immunoreactive band (28 kDa) in luteal tissues and theca cell homogenates that was absent from granulosa cell homogenates. Immunocytochemistry showed KGF predominantly in theca and small luteal cells. Results indicate that bovine CL produce and contain KGF, which is primarily localized in small luteal cells. Therefore, KGF may participate in paracrine communication within the bovine CL.

Effect of gonadotropin-releasing hormone (GnRH) pulse frequency on serum and pituitary concentrations of luteinizing hormone and follicle-stimulating hormone, GnRH receptors, and messenger ribonucleic acid for gonadotropin subunits in cows.

Thirty-two nutritionally anestrous cows were used to determine the effect of the frequency of exogenous GnRH pulses on ovarian follicular growth, serum concentrations of LH and FSH, and concentrations of LH, FSH, GnRH receptors (GnRH-R), messenger RNA (mRNA) for GnRH-R, and mRNA for gonadotropin subunits in the pituitary. Cows were randomly assigned to one of four treatments: 2 micrograms GnRH infused (i.v.) continuously during 1 h, 2 micrograms GnRH infused during 5 min once every hour, 2 micrograms GnRH infused during 5 min once every fourth hour, or saline (control) for 13 days. Infusion of GnRH every hour increased LH concentrations in serum (P < 0.05), but FSH concentrations were not affected by GnRH infusion. Luteal activity (LA) was assessed by the presence of corpora lutea and/or serum progesterone greater than 1 ng/ml. Six of eight cows infused with GnRH every hour had LA by day 13, whereas only 25% of cows infused either continuously or with a pulse every fourth hour had LA by day 13. None of the control cows had LA during the experiment (P < 0.01). Concentrations of LH and FSH in the pituitary were significantly reduced when GnRH was infused hourly or continuously. Concentrations of common alpha and FSH beta mRNA were not influenced by treatment. However, continuous infusion of GnRH decreased (P < 0.05) LH beta mRNA subunit. Concentrations of GnRH-R (P < 0.1) and GnRH-R mRNA (P < 0.05) were reduced when GnRH was infused continuously. We concluded that pulsatile secretion of LH is necessary for follicular growth and LA in beef cattle, and GnRH treatment differentially regulates LH and FSH gene transcription and serum concentrations of LH and FSH in cattle.

Use of force-plate analysis of gait to compare two surgical techniques for treatment of cranial cruciate ligament rupture in dogs.

OBJECTIVE: To use ground reaction forces and related impulses as an objective measurement of limb function in the comparison of 1 extracapsular and 1 intracapsular surgical technique for repair of cranial cruciate ligament rupture in dogs. ANIMALS: 18 healthy dogs. DESIGN: All dogs underwent force-plate analysis of gait prior to transection of the left cranial cruciate ligament. The dogs were randomly allotted to 3 groups. The ligamentous instability was corrected, using a modified retinacular imbrication technique (MRIT) in 1 group and an under-and-over technique in another group. No attempt was made to correct the ligamentous instability in a control group. Clinical grading of lameness and force-plate analysis of gait were performed at 4, 8, 12, 16, and 20 weeks after surgery. PROCEDURE: Peak vertical force and vertical, braking, and propulsion impulses were recorded for each limb at each time. The degree of clinical lameness was graded at each time. RESULTS: Left hind limb peak vertical forces and vertical impulses were significantly decreased at all times after surgery in the control and under-and-over technique group, compared with values before surgery. Dogs of the MRIT group had improved by 20 weeks, with no significant differences between left hind limb peak vertical forces or vertical impulses recorded before surgery and at 20 weeks. CONCLUSION: Peak vertical forces and vertical impulses in dogs undergoing MRIT repair after experimentally created cranial cruciate ligament rupture are not significantly different when values recorded for the operated limb at 20 weeks after surgery are compared with those recorded prior to surgery.

Effects of subject velocity on force plate-measured ground reaction forces in healthy greyhounds at the trot.

Force plate gait analysis was used to study the effects of subject velocity on ground reaction forces. Seven adult Greyhounds were trotted at 3 distinct velocities: 1.5 to 1.8 m/s, 2.1 to 2.4 m/s, and 2.7 to 3.0 m/s. Forelimb and hind limb peak vertical forces increased with increase in velocity (P < 0.05). Forelimb and hind limb vertical impulses decreased as velocity increased (P < 0.05). Significant variations were not observed for craniocaudal or mediolateral peak forces or impulses. It was concluded that velocity significantly (P < 0.05) influenced ground reaction forces and impulses, and must be controlled in experimental design.