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Biomedical subjects

D T Crowe

Publications and source records attributed to D T Crowe.

36 records · Page 2Linked to original sources
PubMed1988

Characterization of the cis and trans elements essential for rat insulin II gene expression.

We have constructed 14 different linker-scanner (LS) mutants throughout the enhancer and promoter of a rat insulin II-CAT fusion gene. These LS mutants were transiently transfected into an insulin-producing (HIT) cell line and three mutants (LS-261/252, LS-102/91, LS-54/45) displayed drastically reduced levels of CAT activity. Therefore, at least three regions are essential for the in vivo expression of an insulin-CAT fusion gene. To identify the trans-acting factors which interact with this cell-specific promoter, we performed band-shifting assays with either HIT or HeLa nuclear extracts and an end-labelled insulin fragment (-100 to +49). Three binding activities were common to both extracts, and another one was unique to HIT cells. DNase I protection studies localized one binding activity to -60 to -40 bp 5' to the cap site. We show that this factor is common to both cell lines and is identical to a previously characterized transcription factor (COUP) which binds to the chicken ovalbumin upstream promoter.

Animals↗
PubMed1986

Use of a nasogastric tube for gastric and esophageal decompression in the dog and cat.

Distension of the stomach with air and fluid was treated successfully in 9 of 10 dogs by use of an indwelling nasogastric tube. A nasogastric tube was used to remove swallowed air and gastric fluid after surgery, as a precautionary measure to prevent recurrence of gastric distention in 2 dogs. A nasoesophageal tube was used to remove retained barium sulfate and saliva in a cat with megaesophagus and esophageal obstruction caused by gastroesophageal intussusception. Passage of the tube through the nose into the esophagus or stomach was easily accomplished in 10 of the 13 animals, requiring only mild restraint and an anesthetic instilled locally into the nostril. Moderate restraint and more than one attempt at passage of the tube through the nose (ventral meatus) were required in the other 3 animals. In one of these, passage through the ventral meatus and into the pharynx could not be accomplished. Of the 12 animals in which the tube was inserted successfully, 11 tolerated it. The tubes remained inserted from 5 minutes to 48 hours (average, 18.5 hours) without clinically detected complications. This technique offers an alternative to orogastric, gastrostomy, or pharyngostomy tubes for initial and continuous intubation and decompression of the stomach and/or esophagus in the dog and cat. It was found to be practical and effective for the removal of air or fluid, but not the removal of coarse food particles.

Animals↗
PubMed1986

Colonic perforation in corticosteroid-treated dogs.

Clinical findings for 5 new cases of colonic perforation in corticosteroid-treated dogs were presented and 8 other cases from the literature were reviewed. Colonic perforation was a fatal complication in all 13 dogs, 12 of which had had recent major surgery. Ten dogs were neurosurgical patients, 1 dog received medical therapy for head trauma and nonambulatory paresis, and 2 dogs were operated on for non-neurologic conditions. Dexamethasone was the most frequently used corticosteroid, and 12 dogs received a mean cumulative dose of 6.4 mg/kg over an average period of 5.1 days. Depression, anorexia, and emesis, the most frequent signs attending colonic perforation, became evident 3 to 8 days after surgery. Signs preceded death by an average of 22.3 hours. Correct antemortem diagnosis (5 dogs) and surgical intervention (3 dogs) had no effect on eventual outcome (mortality = 100%). Colonic perforation most frequently developed in the proximal descending portion and always involved the antimesenteric border. Gross fecal contamination of the peritoneal cavity and acute generalized peritonitis were evident in all but one dog. Adhesions were observed at the lesion site in 6 dogs, but prevented gross soilage in only one dog.

Adrenal Cortex Hormones↗
PubMed1985

Upper airway obstruction. General principles and selected conditions in the dog and cat.

This article presents an overview of the clinical features of upper airway obstructive disorders. It includes more detailed discussions of certain common conditions such as brachycephalic airway syndrome, laryngeal paralysis, and upper airway obstruction due to trauma, foreign bodies, extraluminal masses, and tumours of the larynx and trachea.

Airway Obstruction↗
PubMed1983

Ribosomal RNA gene number and sequence divergence in the diploid-tetraploid species pair of North American hylid tree frogs.

Hyla chrysoscelis (2n = 24) and H. versicolor (2n = 48) are a diploid-tetraploid species pair of tree frogs. Hybridization saturation of isolated 125I-labeled ribosomal RNAs (rRNAs) with filter-immobilized DNA shows that there are twice as many rRNA genes in the tetraploid as in the diploid. For the diploid, saturation occurs at 0.037%, from which it is calculated that there are about 618 copies of the (18 S + 28 S) rRNA genes per haploid genome. Analysis of the extent of hybridization and also the thermal stability of homologous and heterologous hybrids shows that considerably more base substitutions have occurred in the tetraploid rDNA genes than in the diploid since their divergence. This is interpreted to reflect either a relaxation of the gene regulatory "correction" mechanism hypothesized to be responsible for the maintenance of identical tandem rRNA genes in the tetraploid or a release of one gene set from the normal selective constraints.

Animals↗
PubMed1983

Effect of surgery on the in vitro response of canine peripheral blood lymphocytes to phytohemagglutinin.

The effects of surgery (ovario-hysterectomy) and anesthesia on phytohemagglutinin-induced lymphocyte blastogenesis were studied in vitro in 12 dogs. Four dogs had depressed lymphocyte blastogenic responses after surgery. This suppression was transient with normal blastogenic responses occurring in cells from all dogs 24 hours after surgery. Seemingly, T-lymphocyte function may be depressed, only transiently, after surgery.

Anesthesia↗
PubMed1983

AET reduces the frequency of micronuclei in bone marrow cells of mice exposed to gamma radiation.

The purpose of this paper was to determine whether or not a radioprotective agent which binds to DNA and inhibits DNA damage could also provide protection against radiation-induced micronuclei. Male mice were injected intraperitoneally with such an agent, 2-aminoethylisothiouronium bromide hydrobromide (AET), or its solvent 15 min prior to a single 10-min exposure to 60Co gamma rays delivered at various dose rates. Animals were killed 24 hr after irradiation and examined for the frequency of polychromatic erythrocytes containing micronuclei. The results showed a significant dose response to the irradiation for both treatments and a significant reduction in the frequency of micronucleated cells in the mice receiving the radioprotective agent.

Animals↗
PubMed1983

Diagnostic peritoneal lavage before and after abdominal surgery in dogs.

Complete blood cell counts and peritoneal lavage (PL) were done 2 days before and 2 days after abdominal surgery. Abdominal surgery consisted of intestinal resection/anastomosis and cystotomy in 18 dogs in group 1 and gastrotomy, pyloromyotomy, and repair of diaphragmatic laceration in 20 dogs in group 2. Insertion of the dialysis catheter for PL preoperatively in a right paramedian location resulted in more PL samples contaminated with blood than when the catheter was inserted on the abdominal midline. The number of nucleated cells found in PL fluid when the catheter was inserted in a right paramedian location was not significantly different (P less than 0.05) from that observed in PL fluid collected after insertion of the catheter through the abdominal midline. The predominant cell type in preoperative PL fluid was the segmented neutrophil. In groups 1 and 2, WBC counts and nucleated cell counts in PL fluid were significantly increased (P less than 0.05) postoperatively. Segmented neutrophils and macrophages were most frequently present in postoperative PL fluid. Degenerative neutrophils in postoperative PL fluid were associated with the appearance of immature neutrophils in the blood and increased rectal temperature. Dogs with these findings appeared to have more peritoneal inflammation at necropsy than did others in their groups. Concentrations of alkaline phosphatase, alanine aminotransferase, amylase, and creatinine in preoperative PL fluid were extremely low. Except for creatinine in group 2, all of these were significantly increased (P less than 0.05) postoperatively. The complication rate associated with the performance of PL on dogs postoperatively was not greater than that which was observed preoperatively.

Abdomen↗
PubMed1976

Diagnostic abdominal paracentesis and lavage in the evaluation of abdominal injuries in dogs and cats: clinical and experimental investigations.

Abdominal paracentesis and lavage, using a peritoneal dialysis catheter, was evaluated clinically for use in detecting intraabdominal injury in 20 dogs and 3 cats. The technique was also evaluated experimentally in 12 dogs in which various volumes of autogenous blood were infused into the abdomen. The procedure was found to be safe, well tolerated, and reliable in the detection of intraabdominal injuries. The volume of free blood in the abdomen of the experimental dogs was accurately determined. The procedure was superior to physical examination and to needle paracentesis for the early detection and evaluation of intraabdominal injuries.

Abdomen↗
PubMedDate not supplied

Osteofascial compartment syndrome in the dog.

Experimentally induced osteofascial compartment syndrome (OFCS) has been reported in the craniolateral compartment of the canine crus. In this study, anatomic dissections and contrast radiographs were used to describe three additional osteofascial compartments in canine limbs. Experimental OFCS was produced in four different compartments, and caused muscle and nerve pathology in each. When compartment pressures were evaluated in traumatized animals, moderate elevations in compartment pressures were found. A compartment syndrome that developed in one dog was surgically decompressed, returning elevated pressures to a safe level.

Animals↗
PubMedDate not supplied

Rapid tissue expansion for the development of rotational skin flaps in the distal portion of the hindlimb of dogs: an experimental study.

In phase I, tissue expanders were implanted subcutaneously over the lateral crural region of four dogs. The expanders were inflated daily to maintain a constant intraluminal pressure for 7 days. All animals tolerated the pressurized expanders well. Some animal patient discomfort was associated with repeated injections into the subcutaneous filling port. One dog developed a limited area of tissue loss and exposure of the expander. Tissue response to the expanders included epidermal hyperplasia, dermal collagen compression with early fibroplasia, and subcutaneous granulation tissue formation adjacent to the expander pocket. In phase II, a second group of four dogs underwent rapid skin expansion over 7 days. The pressure applied to the expanding skin was determined daily and adjusted to approximate the value reported for capillary pressure in the dog. Tissue discoloration occurred in two dogs, suggestive of impaired circulation. Skin flaps were developed from expanded skin and rotated over the talocrural region. Wound dehiscence occurred along the distal flap margin in three phase II dogs. These wounds healed by second intention. Branches of the caudal saphenous artery were identified, using angiography, as the primary blood supply to the skin flaps.

Animals↗
PubMedDate not supplied

Esophagostomy tubes for feeding and decompression: clinical experience in 29 small animal patients.

Esophagostomy tubes were placed surgically in 13 dogs and 16 cats. The placement technique used was rapid and only required curved forceps, a scalpel blade, and suture material. Flexible tubes (5- to 30-French) were used for feeding liquids or blenderized diets for up to 557 days. Additionally, esophageal and gastric decompression were accomplished using these tubes. Following tube removal, all ostomy wounds healed by second intention without evidence of esophageal stricture or esophagocutaneous fistula. Complications included kinking, placement in an inappropriate location, obstruction, inflammation or infection of the ostomy site, and reflux of feedings.

Animals↗
PubMedDate not supplied

The use of polymeric liquid enteral diets for nutritional support in seriously ill or injured small animals: clinical results in 200 patients.

This prospective, multicenter study evaluated the use of four polymeric liquid enteral (PLE) diets manufactured for dogs and cats in 200 ill or injured patients. Polymeric liquid enteral diets were administered by free-choice feeding, syringe, or feeding tube for up to 208 days. Overall results indicated a 4.9% incidence of vomiting in dogs and a 7.9% incidence in cats; an 8.9% incidence of diarrhea in dogs and an 18.4% incidence in cats. Patients fed the PLE diets seven days or longer had an average increase in body weight of 1.4% in dogs, an average decrease in body weight of 3.8% in cats, increases in lymphocyte counts, and mild decreases in serum albumin.

Aging↗