Common white facial markings in bay and chestnut Arabian horses and their hybrids

Common white facial and leg markings have a multifactorial mode of inheritance in Equus caballus. Evidence for the complexity of the genetic component is the observation that chestnut (e/e) horses have more extensive white markings than do bay (E/-) horses. Computerized records obtained from the Arabian Horse Registry of America, Inc., were used to determine if heterozygous (E/e) bay horses have more extensive white facial markings than do homozygous (E/E) bay horses. Thirty-five sire families were analyzed. Each sire family consists of a sire, his foals, and the dams of those foals. The facial region was divided into five areas, and each horse was given a score from 0 to 5 according to the number of areas with whiteness. Since dams and foals with E/E genotypes cannot be identified in these sire families, mean facial scores were compared in dams and foals that were E/e and E/-. It was assumed that if a difference exists between E/e and E/E horses, the presence of E/E horses in the E/- group would reduce the mean of the E/- group. The results show that Arabian horses with the genotype E/e have more white markings than do horses with the genotype E/-, leading to the conclusion that horses with the genotypes e/e, E/e, and E/E vary as to the quantitative expression of white facial markings, with heterozygotes having an intermediate expression.     

The stability, toxicity and effectiveness of unmodified and phosphorothioate antisense oligodeoxynucleotides in Xenopus oocytes and embryos.

The properties of antisense phosphorothioate and unmodified oligodeoxynucleotides have been studied in Xenopus oocytes and embryos. We find that phosphorothioates, like unmodified oligodeoxynucleotides, can degrade Vg1 mRNA in oocytes via an endogenous RNase H-like activity. In oocytes, phosphorothioate oligodeoxynucleotides are more stable than unmodified oligodeoxynucleotides and are more effective in degrading Vg1 mRNA. In embryos, neither unmodified nor phosphorothioate deoxyoligonucleotides were effective in degrading Vg1 message at sub-toxic doses.     

Evidence for eumelanin and pheomelanin producing genotypes in the Arabian horse

The ultrastructural imaging of melanocytes coupled with analyses to detect sulfur-containing melanosomes by energy-dispersive X-ray spectroscopy were used to test the hypothesis that the yellowish-red and black pigments found in Arabian horses result from pheomelanogenesis and eumelanogenesis, respectively. These procedures detected pheomelanosomes in follicles at the base of hairs in chestnut horses and eumelanosomes in follicles at the base of hairs in black horses. By analyzing tissue obtained by skin biopsy, these procedures also demonstrated that skin melanocytes in a chestnut horse produce eumelanosomes, and follicular melanocytes in the same horse produce pheomelanosomes. It was also shown that the type of follicular melanosome present in light bay horses is correlated with the color of the hair. The results of this study give experimental evidence for the Odriozola-Adalsteinsson hypothesis that the e allele is responsible for the chestnut phenotype; they also give fine structure and chemical confirmation of the action of the A and E loci in the Arabian horse as currently proposed for the mouse and other mammals.     

Hematology and serum chemistry of cottontail rabbits of southern Illinois.

In 1983 and 1984 blood was collected from 79 cottontail rabbits (Sylvilagus floridanus) confined to an outdoor enclosure in southern Illinois to establish reference values for hematology and serum chemistry. Packed cell volume, sodium, potassium, chloride, glucose, calcium, carbon dioxide, blood urea nitrogen, creatinine, uric acid, cholesterol, albumin, bilirubin, alkaline phosphatase, aspartate transaminase, alanine aminotransaminase, total protein, albumin/globulin ratio, and osmolality were measured. Sex and age (adult versus juvenile) of rabbit as well as season (June to September versus October to May) and method of capture (trap versus shot) variously affected most hematology and serum chemistry variables.     

The isolation and properties of phenylalanine hydroxylase from human liver

Phenylalanine hydroxylase was prepared from human foetal liver and purified 800-fold; it appeared to be essentially pure. The phenylalanine hydroxylase activity of the liver was confined to a single protein of mol.wt. approx. 108000, but omission of a preliminary filtration step resulted in partial conversion into a second enzymically active protein of mol.wt. approx. 250000. Human adult and full-term infant liver also contained a single phenylalanine hydroxylase with molecular weights and kinetic parameters the same as those of the foetal enzyme; foetal, newborn and adult phenylalanine hydroxylase are probably identical. The K(m) values for phenylalanine and cofactor were respectively one-quarter and twice those found for rat liver phenylalanine hydroxylase. As with the rat enzyme, human phenylalanine hydroxylase acted also on p-fluorophenylalanine, which was inhibitory at high concentrations, and p-chlorophenylalanine acted as an inhibitor competing with phenylalanine. Iron-chelating and copper-chelating agents inhibited human phenylalanine hydroxylase. Thiol-binding reagents inhibited the enzyme but, as with the rat enzyme, phenylalanine both stabilized the human enzyme and offered some protection against these inhibitors. It is hoped that isolation of the normal enzyme will further the study of phenylketonuria.     

The Value of Pulmonary Function Studies in the Assessment of Patients for Cardiac Surgery

Preoperative pulmonary function, intracardiac pressures and degree of dyspnea were related to the incidence of postoperative respiratory insufficiency in 102 adult patients who underwent cardiac surgery. The purpose was to seek a reliable method of prognosticating the risk of postoperative respiratory insufficiency, especially after the use of cardiopulmonary bypass. When the heart-lung pump was used, 24 of 30 patients with a vital capacity less than 80% of the predicted normal developed respiratory insufficiency, whereas only eight of 41 patients with a normal vital capacity had this complication. In 26 patients where the vital capacity and gas diffusion were both normal, only three developed postoperative respiratory insufficiency. Other single or combined pulmonary function abnormalities, including tests of the mechanics of breathing, were of no greater value in predicting the postoperative course. The degree of dyspnea and the level of intracardiac pressures, although sometimes helpful, were often misleading.     

Directional and anteroposterior asymmetry of common white markings in the legs of the Arabian horse: response to selection

Arabian bay horses manifest, on the average, more common white markings in their hind legs than their forelegs (anteroposterior asymmetry) and more common white markings in their left legs than their right legs (directional asymmetry). To determine if genetic variation exists for these types of asymmetry, the phenotypic response was studied in bay foals when their dams and sires were selected for the directions of fore-hind and left-right differences. In the fore-hind studies, the quantitative shifts in the bay foals were in the direction specified by the selection scheme and the observed deviations were all statistically significant. The shifts were also consistently in the direction favored by selection in the left-right studies, but only two of six observed deviations were statistically significant using a one-tailed test of significance. Thus, only marginal statistical evidence is available to support the observed consistent responses to selection in the left-right studies. These differential responses are reflected in the magnitudes of the heritability estimates. Based on the overall results, it is concluded that both types of asymmetry have a genetic basis in the Arabian horse, but much more genetic variation is present for anteroposterior asymmetry than for directional asymmetry. This revised version was published online in July 2006 with corrections to the Cover Date.     

A study of fluctuating dermatoglyphic asymmetry in the sibs and parents of cleft lip propositi.

Fluctuating asymmetry was studied in cleft lip propositi and their normal sibs and parents. The traits examined were a-b ridge counts and fingerprint patterns. Propositi with a family history of this congenital malformation and their normal sibs and parents were significantly different from the controls for this type of asymmetry. Propositi without a family history and their normal sibs and parents were similar to the controls. These results support the hypothesis that familial and sporadic cases of congenital cleft lip are different entities and give evidence for a genetic mechanism in the parents and sibs of the familial cases that may account for this congenital disorder and, concomitantly, increased fluctuating asymmetry.     

The estrous cycle of captive woodchucks (Marmota monax)

Changes in vaginal cytology were assessed and correlated with temporal changes in circulating concentrations of progesterone (P) and estradiol-17 beta (E2) during the breeding season (February to March) in a seasonally breeding rodent, the woodchuck (Marmota monax). Ten individually caged adult females, maintained under laboratory conditions for 3-11 mo, were studied. Vaginal smears were taken each morning for 2 consecutive months beginning 1 February 1990. Seven of 10 females exhibited readily identifiable estrus, characterized by a clear predominance (83%) of cornified cells. The earliest estrous smear was recorded on 3 February and the latest on 12 March. These animals were monoestrous and remained in a prolonged estrous period during their brief breeding season. The average duration of estrus was 18.1 +/- 2.1 days, ranging from 12-27 days. Levels of P and E2 were determined in serum samples taken before, during, and after estrus from 7 females who exhibited estrus. No changes in the circulating levels of P were apparent during the estrous cycle. However, there was a consistent pattern of estradiol secretion characterized by elevated levels of E2 before and during estrus, followed by a significant (p less than 0.05) decline in E2 levels one week after the end of estrus. Elevated levels of E2 preceded and coincided with maximal degree of vaginal cornification. Thus, the termination, but not the onset, of estrus in woodchucks reflected closely the temporal pattern of changes in serum E2 levels during the breeding season.     

Identification of a potentially neurotoxic pyridinium metabolite of haloperidol in rats

In vivo metabolic studies have revealed that haloperidol is converted to the corresponding pyridinium metabolite which has been characterized in both urine and brain tissues isolated from haloperidol treated rats. Unlike the corresponding conversion of the structurally related Parkinsonian inducing agent MPTP to the ultimate neurotoxic pyridinium metabolite MPP+, the oxidative biotransformation of haloperidol is not catalyzed by MAO-B. Microdialysis studies in the rat indicate that intrastriatal administration of this pyridinium metabolite is about 10% as effective as MPP+ in causing the irreversible depletion of striatal nerve terminal dopamine. The results point to the possibility that some of the neurological disorders observed in experimental animals and man during the course of chronic haloperidol treatment may be mediated by this pyridinium metabolite.