Contributions of biogenic material to the atmospheric ice-nucleating particle population in North Western Europe.

A minute fraction of atmospheric particles exert a disproportionate effect on the phase of mixed-phase clouds by acting as ice-nucleating particles (INPs). To understand the effects of these particles on weather and climate, both now and into the future, we must first develop a quantitative understanding of the major INP sources worldwide. Previous work has demonstrated that aerosols such as desert dusts are globally important INPs, but the role of biogenic INPs is unclear, with conflicting evidence for their importance. Here, we show that at a temperate site all INPs active above -18 °C at concentrations >0.1 L-1 are destroyed on heating, consistent with these INPs being of biological origin. Furthermore, we show that a global model of desert dust INPs dramatically underestimates the measured INP concentrations, but is consistent with the thermally-stable component. Notably, the heat sensitive INPs are active at temperatures where shallow cloud layers in Northern Europe are frequently observed to glaciate. Hence, we suggest that biogenic material is important for primary ice production in this region. The prevalence of heat sensitive, most likely biogenic, INPs in this region highlights that, as a community, we need to quantify the sources and transport of these particles as well as determine their atmospheric abundance across the globe and at cloud altitudes.

Cyclosporine pharmacokinetics in normal and pancreatectomized dogs.

Oral and i.v. cyclosporine (Cs) pharmacokinetics determined from radioimmunoassay (RIA) data were compared in normal and pancreatectomized dogs. An altered pharmacokinetics of Cs was observed in the pancreatectomized dogs that include: a 170% larger central compartment volume; a 34% greater total-body clearance; and lower steady-state average serum concentrations relative to the normals. Even though there were marked intersubject variations, both groups displayed a triexponential decline in Cs serum concentrations and disposition kinetics. Following 7 daily oral doses of commercial cyclosporine (CsA) (20 mg/kg) the Cs serum trough concentrations of the pancreatectomized dogs were consistently below 100 ng/ml, while those of the normal dogs were above 400 ng/ml. No alteration of CsA oral absorption was noted following pancreatectomy. This study suggests that frequent serum Cs concentration monitoring, with appropriate dosage adjustments, even in normals, is necessary to assure adequate drug levels. More significantly, the CsA dosage for pancreatectomized dogs should be several times greater to maintain serum concentrations comparable to normal dogs.

Adenosine triphosphate-magnesium chloride in radiation injury.

Although adenosine triphosphate-magnesium chloride (ATP-MgCl2) has demonstrated cytoprotective effects in a variety of adverse pathophysiologic conditions, its ability to alter radiation injury is unknown. The purpose of this study, therefore, was to assess the effects of ATP-MgCl2 on colorectal radiation injury after preoperative pelvic radiotherapy. Mixed-breed pigs (n = 36) received 4250 cGy preoperative external-beam pelvic radiotherapy (350 cGy fractions three times per week for 4 weeks). During radiotherapy, animals were randomly assigned to one of three treatment groups: (1) intravenous infusions of normal saline during radiotherapy, (2) intravenous ATP-MgCl2 (30 mumol/kg) during radiotherapy, or (3) intravenous ATP-MgCl2 (60 mumol/kg) during each radiotherapy session. After completion of radiotherapy and a 4-week rest period, animals underwent colorectal resection by either the two-layer hand-sewn (n = 18) or stapled end-to-end anastomosis technique (n = 18). Laser Doppler velocimetric readings were obtained to assess mural colonic blood flow after completion of anastomosis. A second laparotomy on postoperative day 5 or 11 was done to examine the following anastomotic parameters: (1) repeat laser Doppler velocimetry, (2) gross inflammatory scoring, (3) bursting pressure, (4) preoperative barium enema to identify leak or stenosis, (5) analysis of anastomotic hydroxyproline content, and (6) incidence of cutaneous injury in the radiation portals. ATP-MgCl2 administered intravenously at 60 mumol/kg led to (1) diminished colorectal seromuscular ischemia evidenced by laser Doppler velocimetric readings, (2) decreased skin and subcutaneous tissue injury in the treatment portals, (3) significantly decreased perianastomotic inflammatory reaction, and (4) increased early hydroxyproline content. There was no significant difference in the incidence of leakage or stenosis between the study groups, nor was the anastomotic bursting strength significantly different between the treatment groups. Therefore the administration of ATP-MgCl2 (60 mumol/kg) appears to offer significant cytoprotection from preoperative pelvic radiation therapy.

Polytetrafluoroethylene versus autogenous vein grafts for vascular reconstruction in contaminated wounds.

A high incidence of dissolution and disruption of infected autogenous vein grafts has been demonstrated. PTFE, on the other hand, has been shown to maintain its structural integrity in the presence of well-entrenched infection, with a relatively small incidence of anastomotic disruption related to host artery necrosis. In addition, PTFE performed as well as autogenous vein when antibiotics were administered. Therefore, PTFE graft material is advocated for controlled clinical trials in patients with contaminated vascular injuries.

The influence of castration on the development of prostatic carcinoma in the dog. 43 cases (1978-1985).

Prostatic carcinoma (PC) was diagnosed in 43 dogs at the Michigan State University Veterinary Clinical Center (MSU-VCC) between 1978 and 1985. Of the 43 dogs with histologically confirmed PC, 19 (44.19%) had been castrated at least three years prior to the development of any prostatic disease. Seven of the castrates had been neutered at less than 12 months of age. Fourteen dogs (32.55%) were presented as intact males at the time of diagnosis. The remaining ten dogs (23.62%) had been castrated as treatment for presumptive prostatic disease prior to referral to the MSU-VCC. Dates of castration were known in all cases. In this study, therefore, castration at any age showed no sparing effect on the risk of development of PC in the dog. The etiology of PC in the dog may not be exclusively related to testicular hormones. Work in humans suggests that the adrenal and pituitary glands play a significant role in the disease. Preliminary work in dogs supports that nontesticular androgens exert a significant influence on the canine prostate.

Carotid body tumors in the dog. Eleven cases (1978-1988).

Case records of 11 dogs with histologically confirmed carotid body tumors were reviewed. Surgical excision had been attempted in ten dogs with carotid body tumors, and one dog had been euthanatized at diagnosis. There were no intraoperative deaths but perioperative mortality was 40%. Horner's syndrome and laryngeal paralysis were the most common postoperative morbidities. The median survival time after surgery alone in the four dogs that survived the perioperative period was 25.5 months (range, 12-45 months). Two dogs treated with postoperative radiation therapy had survival times of 6 and 27 months. Of the six dogs surviving the perioperative period, two dogs are still alive at 19 and 32 months postoperatively. Of the four dogs that died, one was euthanatized 12 months postoperatively for nontumor-related causes. The remaining three dogs died of distant metastases. The carotid body tumors studied were characterized by local tissue invasion, neurovascular complications after therapy, and a propensity to metastasize to multiple sites in the body.

Intracellular magnesium concentrations in dogs with gastric dilatation-volvulus.

OBJECTIVE: To quantify and compare intracellular magnesium concentrations (Mgi) in clinically normal dogs (control dogs) and dogs that have gastric dilatation-volvulus (GDV dogs) and to determine whether there is a difference in Mgi and serum magnesium concentrations (Mgs) between GDV dogs with and without cardiac arrhythmias. ANIMALS: 41 control dogs and 21 GDV dogs. PROCEDURE: Rectus abdominis muscle specimens were obtained from control and GDV dogs for determination of Mgi. Blood samples were obtained from GDV dogs for determination of Mgs, and dogs were monitored for 48 hours for cardiac arrhythmias. Muscle specimens were frozen at -40 C, oven dried at 95 C, and digested with concentrated nitric acid. Multielemental analyses were performed by simultaneous/sequential inductively coupled plasma-atomic emission spectroscopy with fixed-cross flow nebulization. The Mg, was standardized to sulfur content to correct for the amount of fat and fascia in the muscle specimen. Mean (+/- SEM) values were recorded in parts per million (ppm). Results-There were no significant differences in Mgi between control (627 +/- 11.1 ppm) and GDV (597 +/- 20.5 ppm) dogs, in Mgi between GDV dogs with (590 +/- 34 ppm) and without (584 +/- 29 ppm) cardiac arrhythmias, and in Mgs between GDV dogs with (1.77 +/- 0.26 ppm) and without (1.51 +/- 0.09 ppm) cardiac arrhythmias. There was no correlation between Mgs and Mgi (R2 = 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that Mg depletion is not pathophysiologically important in dogs with GDV and does not play a role in the cardiac arrhythmias detected in these patients.

Bacterial population and histologic changes in dogs with perianal fistula.

Ages of 44 dogs with perianal fistula, ranged from 6 months to 13 years (mean, 5.2 years). German Shepherd Dogs and Irish Setters were statistically (P less than 0.01) over-represented compared with those breeds in a canine hospital population (n = 22,047) for the same period. There was a 2:1 male-to-female ratio, with 38 (86.4%) of dogs sexually intact and 6 (13.6%) of dogs neutered. Eleven types of bacterial organisms were recovered from deep perianal tissues of which Escherichia coli, Staphylococcus aureus, beta-hemolytic streptococci, and Proteus mirabilus were most common. Organisms were not recovered from 7 dogs. Of 93 isolates, 88.3% were susceptible to gentamicin, 80.5% to cephalothin, 79.2% to chloramphenicol, and 74% to trimethoprim-sulfamethoxazole. Fifty-one biopsy specimens from 44 dogs were classified as having early, intermediate-, and late-stage lesions based on the amount of fibrosis, severity of the inflammatory response, and, if present, depth of sinus tracts. In most biopsy specimens, all 3 stages were represented in the same histologic section. In 45 specimens, most inflamed lesions were in the dermis of the zona cutanea. Hidradenitis was present in 22 biopsy specimens and was associated with the formation of epithelial-lined sinus tracts.

Thyroid and immunologic status of dogs with perianal fistula.

Lymphocyte-proliferation responses, absolute lymphocyte counts, and thyrotropin-stimulation responses were determined in 33 dogs with perianal fistula; serum immunoglobulin values also were determined in 15 of the 33 dogs. Lymphocytes were stimulated with concanavalin A, pokeweed mitogen, and phytohemagglutinin and were cultured with medium containing normal pooled canine serum or fresh patient's autologous serum. Initially, lymphocytes from 9 dogs (27.3%) had depressed stimulation responses to greater than or equal to 1 phytomitogen, and 4 of the 9 dogs had absolute lymphopenia. One month after recovery in these 9 dogs, lymphocytes from 4 dogs (66.7%) had normal proliferation responses. Of immunoglobulin determinations in 15 dogs, serum IgA values were 32 to 185 mg/dl (mean, 69 +/- 10 mg/dl) and were low in 2 dogs (13%), and serum IgM values were 48 to 610 mg/dl (mean, 263 to 46 mg/dl) and were high in 8 dogs (53%). Serum IgG values were 1,050 to 3,220 mg/dl (mean, 2,339 +/- 165 mg/dl) and were high in 10 dogs (71%). After thyrotropin stimulation, 1 dog was considered hypothyroid. Neither pathogenesis nor prognosis of canine perianal fistula was clarified via immunoglobulin concentrations or absolute lymphocyte counts. Based on lymphocyte-proliferation assays, suppression of cell-mediated immunity was probably a result of perianal fistula, rather than a cause of the fistula.

Treatment of left laryngeal hemiplegia in standardbreds, using a nerve muscle pedicle graft.

The efficacy of a nerve muscle pedicle (NMP) graft in restoring upper airway function was evaluated in exercising horses with induced left laryngeal hemiplegia. The NMP graft was created from the first cervical nerve and the omohyoideus muscle and transplanted into the left cricoarytenoideus dorsalis muscle. Seven adult Standardbreds were trained to exercise on a treadmill inclined at 6.38 degrees. With the horses at rest and exercising at 4.2 and 7.0 m/s, the following variables were recorded: peak inspiratory and expiratory transupper airway pressures (defined as the pressure difference between a lateral tracheal catheter and a mask catheter), peak inspiratory and expiratory air flow, inspiratory and expiratory impedance, tidal volume, minute ventilation, heart rate, and respiratory frequency. Measurements were made before left recurrent laryngeal neurectomy (LRLN), 28 days after LRLN, and 12, 24, and 52 weeks after the NMP graft (n = 5) or sham operation (n = 2). Before LRLN, exercise increased inspiratory and expiratory air flow and transupper airway pressure, whereas the impedance was unchanged. After LRLN, transupper airway inspiratory pressure and impedance were significantly greater and inspiratory air flow was significantly less than baseline values at 7.0 m/s. The sham operation did not improve airway function. Twelve weeks after insertion of the NMP graft, inspiratory impedance and inspiratory air flow were significantly different (improved) from LRLN values. Twenty-four weeks after insertion of the NMP graft, inspiratory impedance was not significantly different from LRLN values.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuromuscular pedicle graft for restoration of arytenoid abductor function in dogs with experimentally induced laryngeal hemiplegia.

Left laryngeal hemiplegia was induced by resection of the left recurrent laryngeal nerve in 12 dogs. A neuromuscular pedicle graft formed from the first cervical nerve and sternothyroideus muscle was transplanted after 1 week to the denervated cricoarytenoideus dorsalis muscle in 8 dogs. The remaining 4 dogs served as controls. Left arytenoid abduction was blindly evaluated by laryngoscopy with video photography at time 0, at 1 week, and at 19 weeks in all dogs. At 19 weeks, biopsy specimens of the left cricoarytenoideus dorsalis muscle and the neuromuscular pedicle were taken from 4 of the treatment dogs, and biopsy specimens of the left cricoarytenoideus dorsalis muscle were taken from the 4 control dogs. All biopsy specimens were blindly evaluated by histologic and histochemical examination. At 36 to 44 weeks, the remaining 4 treatment dogs, from which biopsy specimens had not been taken, were reevaluated by use of laryngoscopy with video photography. Complications and difficulties encountered during surgery included hemorrhage in the area of the cricoarytenoideus dorsalis muscle, location of a branch of the first cervical nerve that was long enough to prevent tension at the graft site, orientation of the muscle pedicle in the cricoarytenoideus dorsalis muscle without the use of an operating microscope, and preservation of the terminal portion of the first cervical nerve while forming the neuromuscular pedicle. Results of the arytenoid movement evaluations revealed improvement in arytenoid abductor function in the treatment group, compared with that in the control group at 19 weeks. Arytenoid abduction in the treatment group at this time, however, was still significantly decreased (P less than 0.05), compared with presurgical movement evaluations.(ABSTRACT TRUNCATED AT 250 WORDS)

Transplantation of pancreatic islets in dogs.

Dispersed pancreatic islet tissue, prepared by collagenase digestion without separation of exocrine and endocrine components, was transplanted into the splenic pulp of 12 dogs made diabetic by total pancreatectomy. Four dogs (group 1) were given autotransplants, and all became euglycemic 4.5 +/- 1.5 days (mean +/- SE) after the transplantation was done. Three of these dogs remained euglycemic until splenectomized 60 days after transplantation was done. Four dogs (group 2) given allogeneic transplants from histocompatible littermates within the same group were administered cyclosporine (40 mg/kg of body weight/day; starting 2 days before transplantation was done until dogs were splenectomized), and 3 of these dogs became euglycemic 8.0 +/- 2.0 days after the transplant was done. Two of the 3 dogs that became euglycemic remained so until splenectomized 60 days after transplantation was done, and the 3rd was euglycemic until 31 days after transplantation. Four dogs (group 3) given allogeneic islet transplants from nonrelated histocompatible donors within the same group were given cyclosporine (40 mg/kg/day; as described for group 2), and none became euglycemic.

Changes in renal function associated with treatment of hyperthyroidism in cats.

We measured glomerular filtration rate (GFR) estimated by plasma disappearance of 99mTc-labeled diethylenetriaminepentaacetic acid, serum concentrations of thyroxine (T4), creatinine, and urea nitrogen, and urine specific gravity in 13 cats with naturally acquired hyperthyroidism before and 30 days after treatment by bilateral thyroidectomy, and in a group of 11 control cats. Mean (+/- SD) serum T4 concentration decreased from a pretreatment value of 120.46 (+/- 39.21) nmol/L to a posttreatment value of 12.15 (+/- 6.26) nmol/L (P < 0.0001; reference range, 10 to 48 nmol/L). Treatment of hyperthyroidism resulted in a decrease in mean (+/- SD) glomerular filtration rate, from 2.51 (+/- 0.69) ml/kg of body weight/min to a posttreatment value of 1.40 (+/- 0.41) ml/kg/min (P < 0.0001). Mean serum creatinine concentration increased from 1.26 (+/- 0.34) mg/dl to 2.05 (+/- 0.60) mg/dl (P < 0.01). Mean serum urea nitrogen concentration increased from 26.62 (+/- 6.83) mg/dl to a mean postthyroidectomy concentration of 34.92 (+/- 8.95) mg/dl (P < 0.01). All changes were significant. Two cats developed overt renal azotemia after treatment of hyperthyroidism. Our results provide further evidence that treatment of hyperthyroidism can result in impaired renal function. In addition, our results suggest that, in some instances, thyrotoxicosis might mask underlying chronic renal insufficiency.

Naproxen-induced toxicosis in a dog.

Naproxen, a nonsteroidal anti-inflammatory drug, induced gastric ulceration and bleeding in a dog. Clinical signs included vomiting, anemia, melena, and weakness. The dog responded to a blood transfusion and supportive treatment (lactated Ringer's solution with added K+ and B vitamins, an antacid, and cimetidine). Naproxen had been given to the dog by the owner, as treatment for shoulder stiffness.

Open peritoneal drainage for treatment of contaminated peritoneal cavity and septic peritonitis in dogs and cats: 24 cases (1980-1986).

The medical records of 22 dogs and 2 cats in which generalized peritonitis had been treated by open peritoneal drainage were reviewed. The age of the affected animals ranged from 5 months to 14 years. The causes of peritonitis were numerous, with the most common being leakage of gastrointestinal contents through spontaneous gastric or intestinal perforations and peritoneal contamination resulting from surgical complications. Bacteria were isolated from 18 (94.7%) of 19 specimens obtained for culturing at the time of diagnosis of peritonitis and from 8 (80%) of 10 specimens obtained for culturing at the time of final abdominal closure. Only 2 (25%) of 8 of the animals in which bacteria were isolated at the time of final abdominal closure died. The overall mortality was 33%. The mortality attributable to peritonitis or its direct complications was 21%. Open peritoneal drainage was tolerated well by all patients.

Radiographic evaluation of esophageal function in Chinese Shar Pei pups.

Liquid barium esophagography was done in 29 clinically normal Chinese Shar Pei pups and observed fluoroscopically, beginning when they were approximately 3 months old and repeated periodically until they were at least 18 months old, if possible. Of these dogs, 69% had relatively slow stimulation of secondary waves, 48% had generalized poor esophageal tone or motility, and 38% had esophageal redundancy. Sequential studies revealed apparent improvement with age for those dogs initially showing slow motility, provided that redundancy was not also present. Another group of 9 Chinese Shar Pei pups had histories of either regurgitation or vomiting. Five of these had hiatal hernia and 2 had megaesophagus.

Renal and ureteral duplication in a dog.

Duplication of a kidney and ureter in an 18-month-old male English Bulldog was demonstrated radiographically and was confirmed surgically. Urinary tract infection had been a problem for a year. Antimicrobial therapy resolved the clinical signs of urinary infection but did not eliminate bacteriuria.

Gastric dilatation-volvulus after splenic torsion in two dogs.

Two dogs developed gastric dilatation-volvulus 2 and 17 months, respectively, after splenectomy for treatment of splenic torsion. Splenic displacement and torsion may stretch the gastric ligaments, allowing increased mobility of the stomach. After splenectomy, an anatomic void may be created in the cranioventral part of the abdomen, contributing to the mobility of the stomach. Veterinarians treating dogs with isolated splenic torsion may wish to consider prophylactic gastropexy at splenectomy, to reduce the chance of future gastric dilatation-volvulus. Prophylactic gastropexy should be done only if the dog's hemodynamic status is stable enough to allow for performance of the additional surgery.

Acute onset of hypokalemia and muscular weakness in four hyperthyroid cats.

Sudden onset of muscular weakness and ventroflexion of the neck were identified in 4 hyperthyroid cats. In each cat, the onset of clinical signs was associated with an acute decrease in serum potassium concentration. The cause for hypokalemia was undetermined, but could have resulted from deficits in total body potassium content or shifts of potassium from the extracellular space into the intracellular space. The 4 cats responded to administration of potassium. Hyperthyroid cats may be prone to disturbances in potassium homeostasis. Clinicians should be aware of potential changes in potassium homeostasis during the treatment of cats with hyperthyroidism.

Surgical correction of late-onset Budd-Chiari-like syndrome in a dog.

An 18-month-old dog was examined because of ascites of 1 month's duration. Typical causes of ascites, including hepatic failure, heart failure, and protein-losing enteropathy, were ruled out. The dog's history included being hit by a car 6 months earlier, and the caudal vena cava had an S shape on thoracic radiographs. In addition, the abdominal fluid had a high protein concentration and low cellular content. These findings were all consistent with a diagnosis of postsinusoidal hypertension secondary to obstruction of hepatic venous outflow (Budd-Chiari-like syndrome). During exploratory thoracotomy, the pericardium appeared to have been torn from the heart and was partially wrapped around the caudal vena cava, causing a constriction. The pericardium was removed and the dog recovered without any further complications. Blunt trauma has been previously reported to cause kinking of the caudal vena cava and Budd-Chiari-like syndrome in dogs; but in these dogs, clinical signs of ascites developed a few days to several weeks after the traumatic incident. It appears that, depending on the cause of the hepatic venous outflow obstruction, onset of Budd-Chiari-like syndrome may be delayed for months.