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Biomedical subjects

D L Barber

Publications and source records attributed to D L Barber.

At least 73 records · Page 4Linked to original sources
PubMed1986

Left hepatic vein attenuation for treatment of patent ductus venosus in a dog.

Patent ductus venosus was identified in a young dog. Surgical attenuation of the anomalous vessel was performed by partial ligation of the left hepatic vein. Clinical signs resolved after surgery, and laboratory values returned to normal. Jejunal venous portography, performed 8 weeks after surgery, revealed complete occlusion of the patent ductus venosus, with normal portal vasculature to the right and central divisions of the liver. Atrophy of the left hepatic division resulted.

Animals↗
PubMed1986

Release and characterization of cholecystokinin from isolated canine jejunal cells.

We have developed an isolated intestinal cell system to study the regulation of cholecystokinin release. Enzymatically dispersed canine jejunal mucosal cells were separated by counterflow elutriation to enrich cholecystokinin content 20-fold. Release of cholecystokinin from freshly isolated cells was determined by radioimmunoassay. Elevated extracellular potassium, dibutyryl cyclic adenosine monophosphate, and the diterpene derivative forskolin each stimulated an increase in cholecystokinin release over a 60-min period compared to basal secretion. L-Tryptophan stimulated a dose-dependent and stereospecific increase in cholecystokinin. D-Tryptophan did not significantly alter basal cholecystokinin secretion. Carbachol inhibited L-tryptophan-stimulated cholecystokinin release in a dose-dependent manner. Analysis of extracts from intact jejunal mucosa by high-pressure liquid chromatography revealed three components with cholecystokinin immunoreactivity eluting in positions with cholecystokinin 8, with cholecystokinin 33/39, and after cholecystokinin 33/39. Only the two molecular forms coeluting, respectively, with cholecystokinin 8 and cholecystokinin 33/39 were present in the elutriator-enriched jejunal cells, and these two forms of cholecystokinin immunoreactivity were released from cells upon stimulation. These data suggest that L-tryptophan directly regulates the release of cholecystokinin and that membrane depolarization and intracellular generation of cyclic adenosine monophosphate may play a role in activating cholecystokinin cells. Stimulated cholecystokinin release is inhibited by the muscarinic agonist carbachol. The molecular profile of released cholecystokinin corresponded to the two molecular components, cholecystokinin 8 and cholecystokinin 33/39, contained in dispersed cells.

Animals↗
PubMed1986

Isolated canine ileal mucosal cells in short-term culture: a model for study of neurotensin release.

We have developed a new technique for maintaining isolated enteric mucosal cells containing neurotensinlike immunoreactivity (NTLI) in short-term culture to determine the regulation of NTLI release. Collagenase-dispersed ileal mucosal cells, separated by centrifugal elutriation, were enriched for NTLI-containing cells as determined by immunohistochemistry and radioimmunoassay. Bombesin (BBS) rapidly stimulated NTLI release from freshly isolated cells. However, studies with freshly isolated cells were limited by high, unstable basal release measurements and rapid degradation of added [3H]neurotensin-(1-13). A culture system of elutriator-enriched NTLI cells was therefore developed. After 48 h NTLI cells selectively adhered to the collagen substrate and constituted 40% of the viable cells in culture. The morphology of NTLI cells in culture closely resembled neurotensin cells in intestinal tissue sections, with a secretory granule diameter of 292 +/- 14 nm. Bombesin stimulated a dose-dependent increase in NTLI secretion over 120 min. In these cell cultures, degradation of added [3H]-neurotensin-(1-13) was minimal over 120 min. High-pressure liquid chromatographic analysis of culture supernatants characterized neurotensin-(1-13) as the primary molecular form of neurotensin released in response to BBS stimulation. In conclusion, we have established a primary culture of enteric neurotensin cells that provides a model for studying the regulation of peptide release. Bombesin stimulation of NTLI release verified the functional responsiveness of this isolated cell system.

Animals↗
PubMed1986

Regulation of neurotensin release from canine enteric primary cell cultures.

A recently developed primary cell-culture system allows direct study of the cellular mechanisms regulating neurotensin secretion from intestinal mucosal cells. We now report the use of these methods to evaluate the modulation of neurotensin release by adrenergic, cholinergic, and peptidergic transmitters. Collagenase-dispersed canine ileal mucosal cells, enriched for neurotensinlike immunoreactivity (NTLI) by centrifugal elutriation, were maintained for 48 h on collagen-coated culture dishes. Epinephrine (0.01-100 microM) stimulated a dose-dependent increase increase in NTLI secretion. The NTLI response to epinephrine increase in NTLI secretion. The NTLI response to epinephrine was competitively inhibited by propranolol, producing a parallel rightward shift of the epinephrine dose-response curve. alpha-Adrenergic agonist methoxamine (10 microM) and clonidine (10 microM) did not alter basal NTLI secretion. Epinephrine stimulation was not significantly inhibited by the alpha-adrenergic antagonists prazosin (10 microM) or yohimbine (10 microM). The diterpene forskolin, an adenyl cyclase activator, increased NTLI release and had an additive effect on the response to epinephrine. In contrast to beta-adrenergic activation, carbachol and somatostatin produced a dose-dependent inhibition of epinephrine-stimulated NTLI release. At 100 microM carbachol, NTLI release was inhibited 68%, and this action was partially blocked by atropine (0.1 microM). Somatostatin (100 nM) produced a 96% inhibition that was not surmountable by 1 mM epinephrine. These data indicate that neurotensin release is stimulated by beta-adrenergic agonists and adenylate cyclase activation. Somatostatin and the muscarinic agonist carbachol directly inhibit NTLI release.

Adenylyl Cyclases↗
PubMed1984

Pelvic bladder in dogs without urinary incontinence.

Double-contrast cystography was performed simultaneously with cystometrography in 6 male and 6 female dogs. All dogs were continent, and results of urinalyses were normal. Initial radiographs were made following intravesical infusion of 0.88 ml of positive contrast medium/kg of body weight. Additional radiographs were made during infusion of CO2. The last radiographs were made at the time of detrusor reflex (11 dogs) or when intravesical pressure reached 50 cm H2O (1 female). An average of 34% (range, 11% to 67%) of bladder length was within the pelvic canal when only the positive contrast medium was infused into the bladders. By the end of CO2 infusion, the bladder neck was more cranially located in 5 of 6 males and in 5 of 6 females. On the last radiographs made, an average of 19% (range, 10% to 35%) of bladder length was within the pelvic canal in 3 of 6 males and in 4 of 6 females. The bladder neck was rounded in 10 of 12 dogs. Thus, it was concluded that previous reports associating pelvic urinary bladder with urinary incontinence and other urologic abnormalities are questionable.

Animals↗
PubMed1984

Cystometry in dogs under oxymorphone and acepromazine restraint.

Cystometry was performed in 12 dogs under oxymorphone and acepromazine restraint. A detrusor reflex occurred in 10 of 12 dogs (83%). Mean threshold pressure and volume were 31 cm H2O and 22 ml/kg, respectively. Tonus limb II varied inversely with threshold volume. Threshold volume varied directly with body weight; threshold pressure was independent of body weight.

Acepromazine↗
PubMed1981

Hyperprolactinemia in monkeys: induction by an estrogen-progesterone synergy.

To evaluate the synergistic effect of estrogens and progesterone on prolactin secretion, rhesus and cynomolgus monkeys in the early follicular phase received estradiol benzoate (100 microgram/kg/day, sc) alone for 14 days, then in combination with progesterone (subcutaneous silastic capsule) for an additional 14 days. Blood was drawn daily by femoral venipuncture under ketamine hydrochloride anesthesia (15 mg/kg). Similarly, this protocol for exogenous steroid treatment was employed in a monkey having a chronically indwelling (femoral insertion into the vena cava) cannula maintained by a vest and mobile tether apparatus; however, no anesthesia was used to obtain serum specimens. In addition, this assembly was applied to six monkeys to determine the acute effects of ketamine hydrochloride on prolactin secretion. Concentrations of prolactin, estradiol-17 beta, and progesterone in serum were determined by conventional radioimmunoassays. Under estrogen therapy alone, mean circulating prolactin levels declined from approximately 15 to less than 5 ng/ml; in contrast, the addition of progesterone caused an abrupt serum prolactin elevation, approximately 8-12 fold. This estradiol-progesterone course led to sustained hyperprolactinemia in the chronically catheterized monkey, whereas ketamine administration raised serum prolactin only briefly, the elevation lasting less than three hours after injection. These findings establish that an estrogen-progesterone synergy, separate from the transient effects of ketamine, induced hyperprolactinemia in cycling monkeys having prevailing levels of estrogen and progesterone near those characteristic of late gestation, when sustained prolactin elevations are observed normally.

Animals↗
PubMed1980

Diskospondylitis in dogs.

During a 3-year period, diskospondylitis was diagnosed in 32 dogs. The condition affected primarily large dogs, with males outnumbering females by approximately 2:1. Diagnosis was made principally by evaluation of radiographs, wherein various degrees of vertebral lysis, sclerosis, and spondylosis were seen. Evaluation of titers for Brucella canis and bacterial cultures of blood, urine, and bone were used to identify the causative organism(s). Six of 24 dogs were seropositive for B canis, 21 of 26 dogs were blood culture-positive, 10 of 23 dogs were urine culture-positive, and 9 of 11 dogs were bone culture-positive. Staphylococcus aureus was the most common organism identified by cultures of blood, urine, and bone. Antibiotic therapy alone and in combination with vertebral curettage was used to treat dogs with minimal neurologic dysfunction. Dogs with severe neurologic deficits were treated with curettage, hemilaminectomy, vertebral immobilization, and antibiotics. Follow-up information was available for 29 dogs. Twenty dogs were clinically normal after treatment. Five dogs were euthanatized because of the severity of neurologic dysfunction; three of these dogs were not treated, and two deteriorated despite treatment. Three dogs died while hospitalized, and one dog died after discharge.

Animals↗
PubMed1980

Endometriosis: role of ovarian steroids in initiation, maintenance, and suppression.

Although endometriosis is commonly associated with infertility, the hormonal requirements for its spontaneous initiation and maintenance remain unknown. Since endometriosis occurs in the monkey, these primates are useful for examining the hormonal dependencies of endometrial plaques. Sequential estradiol and progesterone in Silastic capsules were placed subcutaneously into long-term castrated monkeys (N = 26). Blood samples obtained biweekly were assayed for progesterone and estradiol by radioimmunoassay. Three weeks later, endometriectomies were performed and the minced endometrium was "seeded" into the peritoneal cavity. Thereafter, monkeys were divided into four groups: (1) control, received no therapy; (2) received only estradiol capsules; (3) received only progesterone capsules; and (4) received both estradiol and progesterone capsules. All monkeys underwent laparotomy 4, 12, and 16 weeks after endometrial transplantation to determine whether viable endometrial plaques were present. After 4 weeks, endometriosis was found in all groups, including the controls. At 12 and 16 weeks, monkeys treated with both estradiol and/or progesterone contained viable endometrial plaques, whereas monkeys without steroid supplementation contained only "burnt out" plaques, that is, nonviable endometrial tissue. In conclusion, endometrial tissue transplanted into the peritoneum required no steroid supplementation for initiation. However, once implanted, either estradiol or progesterone, alone or in combination, was required for maintenance. These findings suggest that successful treatment of endometriosis may require both the eradication of existing endometrial plaques and the prevention of reseeding over the peritoneum resulting from retrograde menstruation.

Animals↗
PubMed1980

Canine excretory urogram: correlation with base-line measurements.

Ten healthy, adult mongrel dogs were each given various dose levels of sodium iothalamate IV, and postinjection radiographs were made. Base-line plasma and urine osmolality, glomerular filtration rate, packed cell volume, plasma protein concentration, serum urea nitrogen concentration, serum creatinine concentration, and urine specific gravity were measured. The base-line values and the dose of contrast medium were compared statistically with linear and density measurements made from the post-injection radiographs. Base-line plasma osmolality was directly related to the pyelographic and nephrographic density. The dose of contrast medium directly influenced the kidney length, the kidney, pelvic, diverticular, and ureteral widths, and the renal and diverticular densities despite variations in base-line values within accepted limits.

Animals↗
PubMed1979

Radiographic findings in induced bacterial pyelonephritis in dogs.

Unilateral bacterial pyelonephritis was induced in nine dogs. The upper urinary tracts of these and six control dogs were evaluated by excretory urography prior to and 9 to 10 days following experimental manipulations. Two of the dogs with unilateral pyelonephritis and one control dog were evaluated at intervals throughout a 58-day period. At necropsy, all nine inoculated kidneys were infected, one experimental dog had bilateral pyelonephritis, and one control dog had unilateral pyelonephritis. Most of the infected kidneys had abnormal radiographic changes 9 to 10 days after induction of infection. There was no statistically significant radiographic change in size of infected kidneys at 9 to 10 days. Seven of the 11 infected kidneys and 7 of the 9 inoculated kidneys had renal pelvic and ureteral dilatation. Of the nine dogs with unilateral pyelonephritis, six had decreased opacity of contrast medium in the collecting system and of the vascular nephrogram on the infected side. The size of infected kidneys decreased progressively during the 58-day period. In one of the two dogs evaluated throughout the period, the collecting system of the infected kidney remained dilated; in the other, it returned toward normal size.

Animals↗
PubMed1979

Cranial thoracic diskospondylitis in two dogs.

Cranial thoracic diskospondylitis was diagnosed in 2 dogs. Staphylococcus aureus was isolated from the vertebral lesion of both dogs, from the urine of one dog, and from the blood of the other dog. In each case, curettage of the affected disk and contiguous vertebrae was accomplished via thoracotomy. Both dogs recovered following curettage and antibiotic therapy.

Animals↗
PubMed1979

Normal canine excretory urogram: effects of dose, time, and individual dog variation.

Ten healthy, young, adult mongrel dogs were given sodium iothalamate at dose levels of 200, 400, and 800 mg of iodine/0.45 kg of body weight on separate occasions by rapid IV injection; urinary bladders of the dogs were empty before injections were begun. Seven of the ten dogs were given an additional dose of sodium iothalamate (400 mg of iodine/0.45 kg) with the bladder partially distended with sterilized saline solution. Ventrodorsal abdominal radiographs were obtained immediately and at 5, 10, 20, 40, 60, and 120 minutes after injection of contrast medium. The kidneys, renal pelves, pelvic diverticula, and ureters were evaluated for radiographic density (radiopacity). The lengths and widths of the kidneys, pelves, and diverticula and the width of the ureters were determined, and those measurements were standardized by dividing the values by the corresponding length of the second lumbar vertebral body. From these evaluations, it was determined that postinjection radiographs should be obtained immediately and at 5, 20, and 40 minutes. The optimal dose of contrast medium was 400 mg of iodine/0.45 kg of body weight. It was also determined that the dose of contrast medium, as well as the time of postinjection radiography, significantly influenced many of the measurements (both linear and density) in the excretory urogram of normal dogs. Values for the measurements of the urinary structures based on the results of the present study are also presented.

Animals↗
PubMed1977

Serum estradiol and progesterone during pregnancy and the status of the corpus luteum at delivery in cynomolgus monkeys (Macaca fascicularis).

Levels of estradiol and progesterone in peripheral serum of seven cynomolgus monkeys (Macaca fascicularis) were measured from about the 30th day of pregnancy until parturition. Although the pattern of each steroid in circulation differed somewhat from the respective patterns in rhesus monkeys (Macaca mulatta), there were basic similarities. On the day of delivery, the corpus luteum was excised and in vitro incubation of dispersed luteal cells was performed. Isolated luteal cells produced progesterone under control conditions and responded to the addition of HCG with enhanced steroidogenesis. Accordingly, "rejuvenation" of the corpus luteum may occur during advanced gestation in cynomolgus monkeys. These findings, along with establishing the efficacy of the Subhuman Primate Pregnancy Test kit to diagnose pregnancy in this macaque, extend previous evidence for utility of cynomolgus monkeys as a primate model for study of steroid hormones in pregnancy.

Animals↗