Biomedical subjects

B Schanbacher

Publications and source records attributed to B Schanbacher.

11 recordsLinked to original sources

PubMed2005

Innervation and connexin isoform expression during diabetes-related bladder dysfunction: early structural vs. neuronal remodelling.

Urinary bladder dysfunction is a major complication in diabetes mellitus and its mechanism has been attributed to altered neurological function (autonomic and/or peripheral neuropathy). Previous studies have demonstrated impaired nerve deficiencies, including either loss of nerve function and/or anatomical loss of neuromuscular nerve terminals. While the phenomenon of diabetes-related neurological injury is well recognised, its pathogenesis is not well understood. Using a well established rat model of diabetes (streptozotocin model), we investigated the prevalence of sympathetic and parasympathetic nerves and relative prevalence of connexin isoforms (gap junction proteins) during diabetes-related bladder dysfunction. Immunohistochemistry and digital image analysis was used to detect the prevalence of postsynaptic neuronal markers, NOS1 and connexin isoform expressions. Immunohistochemistry showed significant increases in tyrosine hydroxylase (marker of sympathetic innervation) and decreased vesicular acetylcholine transporter (marker of parasympathetic innervation), predominantly in the smooth muscle layer, 3 days after diabetes induction, when compared to age-matched controls. Time-dependent and cell-specific decreases in the connexin 43 isoform, but transient increases in connexin 32 and 26, were also observed in diabetic rats vs. controls (p<0.05). These data suggest that selective and time-dependent expression of gap junction proteins and altered prevalence of sympathetic/parasympathetic innervation are early events during diabetes-related bladder dysfunction and remodelling.

Animals↗

PubMed2002

Plasma adrenocorticotropin (ACTH) concentrations and clinical response in horses treated for equine Cushing's disease with cyproheptadine or pergolide.

Plasma ACTH levels have been variable in horses with a positive clinical response for therapy for equine Cushing's Disease (ECD). Therefore, our purpose was to determine the value of monitoring plasma adrenocorticotropin (ACTH) levels during treatment of equine Cushing's disease (ECD) with either cyproheptadine (n = 32) or pergolide (n = 10). First, we validated the chemiluminescent ACTH assay (specificity, precision, accuracy, intra-assay and interassay variations) and tested methods of handling the whole blood from the time of collection to when the ACTH was assayed. The sensitivity and specificity of high plasma ACTH levels for detecting ECD was determined in a retrospective study on hospitalised horses (n = 68). Surveys were sent to veterinarians who submitted equine ACTH levels that were high initially and had at least 2 ACTH samples to determine the value of monitoring ACTH levels during therapy of ECD. The ACTH chemiluminescent assay was valid. The ACTH was stable when whole blood was collected and held in plastic tubes for 8 h before separating the plasma. The sensitivity and specificity of plasma ACTH levels for detecting ECD were 84% (n = 19,95% CI 60,97) and 78% (n = 49,95% CI 63,88), respectively. Treated horses generally showed a decrease in plasma ACTH. Plasma ACTH levels may be helpful when monitoring therapy of ECD, although improvement in clinical signs should be considered most important. There were no differences between cyproheptadine and pergolide in terms of improvements in any of the clinical signs.

Adrenocorticotropic Hormone↗

PubMed1989

Function of pancreas allografts more than 1 year following transplantation.

At the University of Iowa, Iowa City, 75 pancreas transplant procedures were performed for type I diabetes mellitus from March 1984 to September 1988. Forty-seven of these transplants were performed simultaneously with kidney transplants from the same donor; 23 followed previous kidney transplants, and 5 were preuremic pancreas-only transplants. The 1-year patient survival rate is 85% and pancreas graft survival rate is 54%. The simultaneous kidney and pancrease group had a 1-year patient survival rate of 82%, a pancreas graft survival rate of 59%, and a renal graft survival rate of 73%. Thirty-one of 70 kidney and pancreas recipients had a functioning pancreas 1 year post transplantation and 26 of 31 currently have a functioning pancreas and are insulin free. Patient symptoms of neuropathy and gastroenteropathy are improved with long-term graft function. Some patients may develop type II diabetes post transplantation with impaired glucose tolerance despite high insulin production by the graft. Pancreas transplantation is the only therapy that achieves a euglycemic state as indicated by glycosylated hemoglobin and glucose tolerance testing. Centers must continue to follow up patients on a long-term basis to determine the final effects on the secondary complications of diabetes.

Diabetes Mellitus, Type 1↗

PubMed1988

Radioimmunoassay of inhibin: serum responses to unilateral and bilateral orchidectomy.

An overnight double antibody RIA using a rabbit antiserum to porcine inhibin alpha-chain [Tyr30] (1-30) NH2 [pI alpha(1-30)], radioiodinated pI alpha(1-30), and a preprecipitated second antibody complex has been developed to measure inhibin concentrations in sera and other biological fluids. The assay is accurate, precise (intraassay coefficient of variation, 4.8%), sensitive (25 pM; 2.5 fmol/tube), and specific for inhibin. The synthetic reference standard pI alpha(1-30) produced a displacement curve that paralleled intact male ovine and bovine sera, crude bovine follicular fluid, and a partially purified porcine follicular fluid reference preparation (WHO/NIH 86/690). Bilateral castration of prepubertal and postpubertal ram lambs resulted in a rapid decrease in serum inhibin concentrations and a subsequent increase in serum FSH. Inhibin levels were high in prepubertal lambs (approximately 375 pM), but these levels were not sustained near the time of puberty (approximately 180 pM). Intensive sampling by jugular venipuncture after castration indicated a 50% drop in circulating inhibin levels within 2 h of testes removal with chronic castrate levels (approximately 75 pM) achieved by 6 h postcastration. A rapid fall in circulating levels of inhibin was also observed after unilateral castration, but these values stabilized within hours to levels intermediate (i.e. approximately 200 pM) to those of intact and bilateral castrate rams. Hemicastrates exhibited a more subtle rise in serum FSH after testis removal, with FSH and inhibin levels of prepubertal hemicastrates returning to mature intact ram values by 15 weeks of age. Serum inhibin levels remained low and FSH levels high at 14 days in unilateral castrate postpubertal rams. Inhibin immunoreactivity increased abruptly in castrate ewes and rams injected iv with 5 ml bovine follicular fluid. Serum inhibin reached 300 pM immediately after bovine follicular fluid injection, and castrate FSH levels decreased 30% to a nadir 8 h later. These physiological findings provide support for the validity and utility of this inhibin RIA and further suggest that the Sertoli cells (not the germ cells) are the likely source of the FSH release-inhibiting factor from the testis.

Aging↗

PubMed1987

[Augmentation, by naloxone, of the frequency and amplitude of LH-RH pulses in hypothalamo-hypophyseal portal blood in the castrated ram].

The effect of naloxone administration on the LH-RH secretion in hypophyseal portal blood and LH secretion in peripheral blood was studied in four short term castrated rams (between 2 to 4 days after castration). For two animals (A and B) given a single naloxone injection, an increase of LH-RH pulse amplitude was observed (A, 22.3 to 80.5 pg/ml and B, 22.5 to 34.5 pg/ml) with only a small (nonsignificant) increase in LH-RH pulse frequency. For animals C and D given four injections of naloxone, both LH-RH pulse amplitudes and LH-RH pulse frequency were increased. Means of LH-RH pulse amplitude increase from 29.3 to 65.1 pg/ml and from 34.6 to 50.8 pg/ml for animals C and D respectively and the number of LH-RH pulses detected during the 3 hrs. before and after the first injection of naloxone were respectively 3 vs. 5 and 3 vs. 7. Whereas all LH pulses were preceded with a LH-RH pulse in animals A and B, after the multiple naloxone injections in animals C and D, a rapid LH-RH pulse frequency was associated with a sustained increment of LH secretion in peripheral blood in such a way that individual LH pulses were not clearly defined. The present report is the first documentation on naloxone increasing the release of LH-RH secretion in hypophyseal portal blood of conscious, unrestrained, short-term castrated rams. The results indicate: (1) that the opiate antagonist naloxone is able to increase both the amplitude and the frequency of LH-RH discharge by the hypothalamus and (2), when the LH-RH pulse frequency exceeds one pulse every 30 min., discrete LH secretory episodes are not observed in peripheral blood.

Animals↗

PubMed1987