Reproductive careers of Thoroughbred broodmares before and after surgical correction of ≥360 degree large colon volvulus.

BACKGROUND: Limited data exist describing broodmare longevity and reproductive efficiency after surgical correction of ≥360 degree large colon volvulus (° LCV). OBJECTIVES: Compare career duration and foals delivered for broodmares before and after ≥360° LCV surgery. STUDY DESIGN: Retrospective case series. METHODS: Broodmares registered with The Jockey Club that had surgical correction of ≥360° LCV and survived to hospital discharge at Rood and Riddle Equine Hospital from 1 January 2000 to 31 December 2015 were included. Information was collected from the hospital's medical data base and The Jockey Club produce records about the mares' reproductive careers. Data were evaluated using parametric and nonparametric tests, P≤0.05. RESULTS: Mares that were bred but never foaled prior to surgery (n = 19) had shorter careers (mean ± standard deviation [s.d.]), 4.4 ± 4.5 years, and fewer foals, 3.1 ± 3.3, compared with mares that delivered ≥1 foal before surgery (n = 565), 10.4 ± 4.5 years and 7.4 ± 3.4 foals, respectively, P<0.001. Broodmares that delivered foals before surgery produced more foals in the years before surgery, 4.8 ± 3.0, than after surgery, 2.6 ± 2.4, P<0.001, and had longer breeding careers, 5.9 ± 3.8 vs. 4.5 ± 3.3 years before compared with after surgery, P<0.001. No significant differences in career length or number of foals delivered were detected for mares with a single compared with multiple LCV surgeries. Mares that were 3-11 years old at the time of surgery had significantly more foals after surgery compared with mares ≥12 years old, P<0.001, as expected. MAIN LIMITATIONS: Retrospective collection of data. CONCLUSIONS: Broodmares had productive careers following surgery for ≥360° LCV that were largely influenced by the mares' age at the time of surgery.

Hereditary aspects of decreased hypoxic response.

Decreased ventilatory responses to hypoxia and hypercapnia have been demonstrated in a variety of disorders; however, the etiology of these decreased drives remains virtually unknown. Recent observations have suggested a familial influence on hypoxic and hypercapnic ventilatory response, but it is unclear whether this influence is the result of hereditary or environmental influences. Therefore we measured the ventilatory response to isocapnic hypoxia (HVR) and hyperoxic hypercapnia in 12 pairs of identical and 12 pairs of nonidentical twins. Significant correlation (P less than 0.01) was found for HVR within identical twin pairs but not within nonidentical twin pairs. Identical twins resembled each other more closely with respect to HVR than was the case for nonidentical twins (P less than 0.0125). This was independent of body size, blood PCO2, or pH. No such correlation could be found for ventilatory response to hyperoxic hypercapnia. It is concluded that hereditary influences affect HVR and it is speculated that such influences may play a role in clinical conditions characterized by decreased hypoxic ventilatory responses.

Creatinine concentrations of accumulated intrauterine fluid to confirm the clinical diagnosis of urometra in mares.

Urine pooling, as a persistent condition, is a cause of infertility in mares due to endometrial inflammation and sperm toxicity. Identification of urometra can be challenging in mares presenting with the condition intermittently, or when urine flows into the uterus but is undetectable in the vagina. Currently, there are no reported objective methods to confirm the clinical diagnosis of urine contamination in intrauterine-fluid accumulations. Since creatinine is present in high concentrations in urine and does not diffuse across cell membranes, creatinine concentration should be increased in mares with urometra, but negligible in normal and mares with intrauterine fluid accumulation (non-urometra cases). To test this hypothesis, creatinine concentrations of intrauterine fluid were measured in mares with a clinical diagnosis of urine accumulation (n=9) or intrauterine fluid containing no urine (n=10). Results showed that creatinine concentrations (mg/dl) were significantly higher in mares that had a clinical diagnosis of urometra (42.8±12.6, range 4.1-109.2) compared with those that did not (0.38±0.1, range 0-0.9). Also, two mares after urethral extension surgery demonstrated a remarkable reduction in creatinine concentrations. This study highlights an undocumented approach to confirm a clinical diagnosis of urometra in mares; the authors anticipate that testing for creatinine in the uterine fluid of mares may become a standard tool for identifying urometra in mares and confirming the success of urogenital surgeries.

Down's syndrome as a model disease.

Aneuploid chromosomal disorders may offer insight into the pathogenesis of certain common diseases. The birth defects and mental retardation that characterize Down's syndrome are well recognized. In addition, the altered chromosomal content that occurs in the syndrome apparently affects the prevalence of a variety of disorders, such as malignancy, endocrine dysfunction, infection, atherosclerosis, and premature aging. Because the single distinguishing factor in Down's syndrome is the presence of an excess of a part of chromosome 21, the genetic information contained in this chromosomal segment seems to be responsible for the disease manifestations. Techniques of somatic cell genetics and molecular biology allow mapping of human genes and study of their expression. With such methods it should be possible to understand Down's syndrome and other aneuploid disorders and to apply these considerations to other areas of medicine.

Moderate alcohol dose and chronic obstructive pulmonary disease: not a cause of hypoventilation.

Six patients with chronic obstructive pulmonary disease (COPD) (forced expiratory volume in one second, 1.01 +/- 0.08 L [mean +/- SEM] ) were given either 1 mL of 100% alcohol per kilogram of body weight in an aqueous solution or a similar volume of water in a crossover design on consecutive days. All subjects became intoxicated and the peak alcohol concentration was 137 +/- 11 mg/dL, 40 minutes after ingestion. No significant difference was found in either PaO2 or PaCO2 between the alcohol and control period. A significant decrease in arterial pH occurred following alcohol (P less than .05), and represented a mild metabolic acidosis. Alcohol ingestion resulted in an increase in oxygen consumption (P less than .05) and carbon dioxide production (P less than .05) but no change in respiratory rate. It appears that small to moderate amounts of alcohol will not cause marked changes in oxygen tension or alveolar hypoventilation in patients with severe COPD who do not have marked hypercapnia. Nevertheless, other effects of alcohol on the cardiopulmonary system and the concomitant use of sedatives have to be considered before condoning the use of alcohol.

Tuberculosis of the skull.

Because tuberculosis of the skull is relatively unusual occurrence, it may not be immediately recognized. It responds readily to chemotherapy and should be suspected in disseminated tuberculosis or in any draining lesion of the skull that is sterile or fails to respond to conventional antibiotic therapy.

Impaired oxygenation during sleep in excessive polycythemia of high altitude: improvement with respiratory stimulation.

Although polycythemia of high altitude is usually due to excessive hypoxemia, in some patients the hematocrit is elevated out of proportion to the degree of hypoxemia measured awake. One possible explanation is that severe hypoxemia occurs during sleep in these subjects. We therefore monitored oxygen saturation (SaO2), breathing pattern, and electroencephalogram (EEG) during sleep in five normal high-altitude residents and in five patients with excessive polycythemia. The polycythemic patients were studied as part of a placebo--drug double-blind crossover trial of the respiratory stimulant drug medroxyprogesterone acetate (MPA). The polycythemic patients while taking placebo were much more hypoxemic during sleep than the normals (all-night mean SaO2: 79.4 +/- 1.7% versus 87.8 +/- 1.7%, p less than 0.01). Abnormalities in breathing patterns were observed in all the subjects, especially during REM stage sleep. In polycythemic subjects, this resulted in precipitous hypoxemia with SaO2 as low as 50%--70%. Severe hypoxemia was not observed in control subjects despite similar abnormalities in breathing. Significant improvement in nocturnal SaO2 occurred when the polycythemic patients were taking MPA, mean SaO2 rising from 79.4 +/- 1.7% to 83.7 +/- 0.7%, p less than 0.05. Of probably greater importance, MPA largely prevented the precipitous drops in SaO2, mean lowest SaO2 rising from 64.6 +/- 4.7% to 76.0 +/- 2.1% p less than 0.05. The severe decreases in SaO2 during sleep may explain elevations in hematocrit that are out of proportion to the awake SaO2 in man at high altitude. The therapeutic effect of MPA in this condition may be due to amelioration of sleep hypoxemia.

Exercise-induced asthma.

Exercise-induced bronchospasm is a common condition of patients who have asthma. Its mechanism appears to be related to cooling of the airways. Clinically, it can be managed by pretreatment with beta-adrenergic medications or cromolyn. Measures to protect the airway from excessive loss of heat, such as the use of scarves or participating in indoor activity, are also effective strategies in its management.

Fiberoptic bronchoscopy in bronchial asthma. A word of caution.

Three instances of intense laryngospasm and bronchospasm occurred as a result of fiberoptic bronchoscopic examination in three patients with quiescent bronchial asthma. The indications for the procedure were hemoptysis in one patient and lobar collapse in two. It is likely that vagally mediated reflex laryngospasm and bronchoconstriction occur when irritant receptors are mechanically stimulated by the bronchoscope. Therefore, in the asthmatic population with its increased airway reactivity, indications for fiberoptic bronchoscopy should be absolute, and the procedure should be performed under optimal conditions. A rationale for minimizing the risk of this procedure in patients with bronchial asthma is discussed.

Bitolterol compared to isoproterenol in advanced chronic obstructive pulmonary disease.

Twenty-eight patients with advanced emphysema and/or chronic bronchitis and severe airflow obstruction were randomly assigned to receive either bitolterol or isoproterenol aerosol delivered by a metered dose device which was administered three times daily. Randomization resulted in similar patients with like degrees of airflow obstruction and responsiveness to a test dose of inhaled bronchodilator. Significantly greater improvement in airflow was achieved by administration of bitolterol compared to isoproterenol. Pharmacologic responses continued after 90 days of daily dosing. Both drugs were well tolerated and side effects included mild degrees of tachycardia for both drugs. Two patients assigned to isoproterenol stopped therapy during the study due to side effects. This study indicates that bitolterol is more effective than isoproterenol in degree and duration of bronchodilatation in patients with advanced chronic obstructive pulmonary disease.

Somatic cell genetic approaches to Down's syndrome.

Somatic cell genetic analysis of mutants of Chinese hamster ovary cells with deficient purine synthesis and of hybrids between these mutants and human cells is described. Data are presented substantiating that two genes for enzymes of purine synthesis, AdeC and AdeG, can be coordinately regulated in mammalian cells. Analysis of a human-hamster hybrid cell, Ade C/21, which contains a normal complement of hamster chromosomes and human chromosome 21 as its only human genetic component recognizable by electrophoretic and immunogenetic techniques demonstrates that genes associated with the presence of human chromosome 21 and required for the synthesis of specific polypeptides and specific human lethal cell surface antigens can be detected in these hybrids.

Aerosolized terbutaline sulfate in the treatment of bronchospasm.

Terbutaline sulfate, a relatively selective beta2 agonist, is indicated for the treatment of bronchospasm associated with chronic obstructive pulmonary disease. Studies have shown that when administered via an aerosol, terbutaline has a rapid onset, a prolonged duration of action, and a low incidence of systemic side effects. Because the drug is delivered directly to the bronchi, one can administer low doses of aerosolized terbutaline and achieve a bronchodilatory effect comparable to that achieved with higher doses of the oral form.

Application of molecular biology to pulmonary disease.

The techniques of molecular biology now make it possible to clone specific genes, determine the nature of their molecular message, produce their protein product, and study their function in health and disease. DNA probes, particularly those for ribosomal RNA, offer a new way for the diagnosis of infectious diseases affecting the lung, particularly TB. In addition, recombinant DNA libraries of mycobacteria can be used to isolate mycobacterial antigens recognized by patients with TB. This may allow development of better immunologic tests and vaccines. A specific chromosomal abnormality of human chromosome 3 has been found in small cell lung cancer. It is hypothesized that loss of genes from this region may play a role in the pathogenesis of lung cancer. Another important factor in development of the disease is the expression of cancer-associated oncogenes. In addition to insights into the biology of lung cancer, these oncogenes might provide a method to classify various types of lung cancer and predict response to therapy. Specialized DNA markers known as RFLPs have now been linked with CF. This has resulted in localization of the CF gene to human chromosome 7 and the detection of the gene in most of its carriers who have been studied. Knowing where the gene resides and use of techniques of genetic engineering will eventually allow isolation of the CF gene (or genes) on chromosome 11 and determination of the biochemical defect for which it codes. Similarly, the gene for human alpha 1-antitrypsin has also been cloned. A practical benefit is the production of normal and mutant enzyme for replacement therapy in patients.

DNA molecular biology in the diagnosis of pulmonary disease.

DNA molecular biology is becoming increasingly important in clinical medicine. It has provided a new method to diagnose an inherited pulmonary disease in which the biochemical defect has been defined. Alpha-1-antitrypsin deficiency can now be diagnosed by direct analysis for the disease gene. In cystic fibrosis, another inherited pulmonary disease, the biochemical defect has not yet been defined. However, the search has been narrowed. The cystic fibrosis genetic defect has recently been localized to the long arm of chromosome 7. Because polymorphic DNA markers (RFLPs) are available for this region of chromosome 7, it is now often possible, using linkage analysis, to trace the inheritance of the cystic fibrosis gene(s) in families known to have cystic fibrosis. When the cystic fibrosis genetic defect is defined, it will then be possible to look directly for the disease gene. Finally, the greatest impact in clinical medicine may well be the development of rapid DNA hybridization techniques to diagnose infectious diseases that currently take days to weeks to diagnose.

Equine sperm-oocyte interaction: results after intraoviductal and intrauterine inseminations of recipients for oocyte transfer.

Insemination of recipients for oocyte transfer and gamete intrafallopian transfer (GIFT) in five experiments were reviewed, and factors that affected pregnancy rates were ascertained. Oocytes were transferred into recipients that were (1) cyclic and ovulated at the approximate time of oocyte transfer, (2) cyclic with aspiration of the preovulatory follicle, and (3) noncyclic and treated with hormones. Recipients were inseminated before, after, or before and after transfer. Intrauterine and intraoviductal inseminations were done. Pregnancy rates were not different between cyclic and noncyclic recipients (8/15, 53% and 37/93, 39%). The highest numerical pregnancy rates resulted when recipients were inseminated with fresh semen from fertile stallions before oocyte transfer or inseminated with cooled transported semen before and after oocyte transfer. Oxytocin was administered to recipients before oocyte transfer when fluid was imaged within the uterus. Administration of oxytocin to recipients at the time of oocyte transfer resulted in significantly higher pregnancy rates than when oxytocin was not administered (17/26, 65% and 28/86, 33%). Intraoviductal and intrauterine inseminations of recipients during oocyte transfer resulted in similar embryo development rates when fresh semen was used (12/22, 55% and 14/26, 55%). However, embryo development rates significantly reduced when frozen (1/21, 5%) versus fresh sperm were inseminated into the oviduct. Results suggest that insemination of a recipient before and after transfer could be beneficial when semen quality is not optimal; however, a single insemination before transfer was adequate when fresh semen from fertile stallions was used. Absence of a preovulatory follicle did not appear to affect pregnancy rates in the present experiments. The transfer of sperm and oocytes (GIFT) into the oviduct was successful and repeatable as an assisted reproductive technique in the equine.

Clinical evaluation of a new ear oximeter.

Ear oximetry offers a noninvasive method of determining and monitoring oxygen saturation in arterialized capillary blood. A new apparatus has recently been developed which provides improved accuracy as well as increased ease of use. We have found it to be at least as accurate as the American Optical oximeter which measures oxygen saturation directly from arterial blood. It has proved to be of value in clinical situations such as monitoring critically ill patients (particularly those being mechanically ventilated) and patients undergoing treadmill exercise or fiberoptic bronchoscopy and in the diagnosis of disorders characterized by periodic hypoxia.

Embryo development rates after transfer of oocytes matured in vivo, in vitro, or within oviducts of mares.

Objectives of the present study were to use oocyte transfer: 1) to compare the developmental ability of oocytes collected from ovaries of live mares with those collected from slaughterhouse ovaries; and 2) to compare the viability of oocytes matured in vivo, in vitro, or within the oviduct. Oocytes were collected by transvaginal, ultrasound-guided follicular aspiration (TVA) from live mares or from slicing slaughterhouse ovaries. Four groups of oocytes were transferred into the oviducts of recipients that were inseminated: 1) oocytes matured in vivo and collected by TVA from preovulatory follicles of estrous mares 32 to 36 h after administration of hCG; 2) immature oocytes collected from diestrous mares between 5 and 10 d after aspiration/ovulation by TVA and matured in vitro for 36 to 38 h; 3) immature oocytes collected from diestrous mares between 5 and 10 d after aspiration/ovulation by TVA and transferred into a recipient's oviduct <1 h after collection; and 4) im mature oocytes collected from slaughterhouse ovaries containing a corpus luteum and matured in vitro for 36 to 38 hours. Embryo development rates were higher (P < 0.001) for oocytes matured in vivo (82%) than for oocytes matured in vitro (9%) or within the oviduct (0%). However, neither the method of maturation nor the source of oocytes affected (P > 0.1) embryo development rates after the transfer of immature oocytes.

Pregnancies from vitrified equine oocytes collected from super-stimulated and non-stimulated mares.

The objectives were to compare embryo development rates after transfer into inseminated recipients, vitrified thawed oocytes collected from super-stimulated versus non-stimulated mares. In vivo matured oocytes were collected by transvaginal, ultrasound guided follicular aspiration from super-stimulated and non-stimulated mares 24-26 h after administration of hCG. Oocytes were cultured for 2-4 h prior to vitrification. Cryoprotectants were loaded in three steps before oocytes were placed onto a 0.5-0.7 mm diameter nylon cryoloop and plunged directly into liquid nitrogen. Oocytes were thawed and the cryoprotectant was removed in three steps. After thawing, oocytes were cultured 10-12 h before transfer into inseminated recipients. Non-vitrified oocytes, cultured 14-16 h before transfer, were used as controls. More oocytes were collected from 23 non-stimulated mares (20 of 29 follicles), than 10 super-stimulated mares (18 of 88 follicles; P < 0.001). Of the 20 oocytes collected from non-stimulated mares, 12 were vitrified and 8 were transferred as controls. After thawing, 10 of the 12 oocytes were morphologically intact and transferred into recipients resulting in one embryonic vesicle on Day 16 (1 of 12 = 8%). Fourteen oocytes from super-stimulated mares were vitrified, and 4 were transferred as controls. After thawing, 9 of the 14 oocytes were morphologically intact and transferred into recipients resulting in two embryonic vesicles on Day 16 (2 of 14 = 14%). In control transfers, 7 of 8 oocytes from non-stimulated mares and 3 of 4 oocytes from super-stimulated mares resulted in embryonic vesicles on Day 16. The two pregnancies from vitrified oocytes resulted in healthy foals.

Strategies to improve the ovarian response to equine pituitary extract in cyclic mares.

Equine pituitary extract (EPE) has been reported to induce heightened follicular development in mares, but the response is inconsistent and lower than results obtained in ruminants undergoing standard superovulatory protocols. Three separate experiments were conducted to improve the ovarian response to EPE by evaluating: (1) effect of increasing the frequency or dose of EPE treatment; (2) use of a potent gonadotropin-releasing hormone agonist (GnRH-a) prior to EPE stimulation; (3) administration of EPE twice daily in successively decreasing doses. In the first experiment, 50 mares were randomly assigned to one of four treatment groups. Mares received (1) 25 mg EPE once daily; (2) 50 mg EPE once daily; (3) 12.5 mg EPE twice daily; or (4) 25 mg EPE twice daily. All mares began EPE treatment 5 days after detection of ovulation and received a single dose of cloprostenol sodium 7 days postovulation. EPE was discontinued once half of a cohort of follicles reached a diameter of >35 mm and hCG was administered. Mares receiving 50 mg of EPE once daily developed a greater number (P = 0.008) of preovulatory follicles than the remaining groups of EPE-treated mares, and more (P = 0.06) ovulations were detected for mares receiving 25 mg EPE twice daily compared to those receiving either 25 mg EPE once daily and 12.5 mg EPE twice daily. Embryo recovery per mare was greater (P = 0.05) in the mares that received 12.5 mg EPE twice daily than those that received 25 mg EPE once daily. In Experiment 2, 20 randomly selected mares received either 25 mg EPE twice daily beginning 5 days after a spontaneous ovulation, or two doses of a GnRH-a agonist upon detection of a follicle >35 mm and 25 mg EPE twice daily beginning 5 days after ovulation. Twenty-four hours after administration of hCG, oocytes were recovered by transvaginal aspiration from all follicles >35 mm. No differences were observed between groups in the numbers of preovulatory follicles generated (P = 0.54) and oocytes recovered (P = 0.40) per mare. In Experiment 3, 18 mares were randomly assigned to one of two treatment groups. Then, 6-11 days after ovulation, mares were administered a dose of PGF2, and concomitantly began twice-daily treatments with EPE given in successively declining doses, or a dose of PGF2alpha, but no EPE treatment. Mares administered EPE developed a higher (P = 0.0004) number of follicles > or = 35 mm, experienced more (P = 0.02) ovulations, and yielded a greater (P = 0.0006) number of embryos than untreated mares. In summary, doubling the dose of EPE generated a greater ovarian response, while increasing the frequency of treatment, but not necessarily the dose, improved embryo collection. Additionally, pretreatment with a GnRH-a prior to ovarian stimulation did not enhance the response to EPE or oocyte recovery rates.