Pneumothorax in a dog caused by necrotizing pneumonia secondary to heatstroke.

OBJECTIVE: To describe the clinical course, diagnostic findings, medical and surgical treatments, and outcome in a dog with spontaneous pneumothorax secondary to necrotizing pneumonia thought to be a delayed complication of heatstroke. CASE SUMMARY: A 1.5-year-old Labrador Retriever developed spontaneous pneumothorax 12 days after an episode of exertional heat stroke. Computed tomography was performed and showed bilateral pneumothorax and multifocal pulmonary consolidation, especially at the lung periphery. A median sternotomy was performed, and multifocal, well-demarcated areas of consolidated pulmonary tissue with purple discoloration were identified and resected from the right middle, right caudal, and accessory lung lobes. Histologic examination of the resected pulmonary tissue indicated necrotizing pneumonia, and bacteriologic culture of the tissue resulted in growth of Pseudomonas aeruginosa. Examination of tissue from a pectoral muscle biopsy performed at this time showed necrotizing myopathy. The dog was discharged 7 days after surgery and made a full recovery. NEW OR UNIQUE INFORMATION PROVIDED: This case report describes pneumothorax and multifocal necrotizing pneumonia as a delayed complication of heatstroke, and provides the first description of the computed tomography appearance of histologically confirmed necrotizing pneumonia in a dog. Multifocal necrotizing pneumonia with or without pneumothorax should be considered in dogs that develop respiratory distress following severe systemic illness.

Effects of sample site and size, skin tension lines, surgeon, and formalin fixation on shrinkage of skin samples excised from canine cadavers.

OBJECTIVE: To assess the effects of sample size and location, skin tension lines, surgeon, and formalin fixation on the extent of shrinkage that occurs in excised canine skin samples. ANIMALS: Cadavers of 4 adult purpose-bred mixed-breed hound dogs with grossly normal skin. PROCEDURES: 54 circular areas of skin (2-, 4-, and 6-cm-diameter samples from each of 9 body regions on each side) were excised by 1 of 2 surgeons from each cadaver. The diameter of each sample was measured in 4 orientations (parallel to previously reported tension lines, perpendicular to tension lines, in a dorsoventral orientation, and in a craniocaudal [or rostrocaudal] orientation) at 3 time points (before and immediately after excision and after 24 hours of formalin fixation). RESULTS: 216 samples were measured in all 4 orientations at all 3 time points. For all samples, mean ± SE decrease in diameter after fixation, compared with pre-excision findings, was 6.2 ± 0.7 mm. No significant correlations were found between percentage of skin shrinkage and surgeon, body side or region, or measurement orientation in relation to skin tension lines. The mean sample diameter immediately after excision differed significantly from that before excision (mean diameter decrease, 5.5 ± 0.7 mm). Overall, sample diameter immediately after excision and after formalin fixation did not differ. CONCLUSIONS AND CLINICAL RELEVANCE: The extent of shrinkage of skin samples from hound cadavers that occurred immediately after excision was notable. A better understanding of the effectors of excised skin sample shrinkage is needed, especially when histopathologic findings provide guidelines for surgical margins.

Measuring level of agreement between values obtained by directly measured blood pressure and ultrasonic Doppler flow detector in cats.

OBJECTIVE: To determine if blood pressure measured with an ultrasonic Doppler flow detector (Doppler) is in good agreement with directly measured blood pressures in anesthetized cats. DESIGN: Prospective observational study. SETTING: University veterinary teaching hospital. ANIMALS: Thirty-nine cats undergoing routine neutering. INTERVENTIONS: Cats were divided into 2 groups; 19 cats enrolled in Group A had a 24-Ga catheter inserted into a dorsal pedal artery; 20 cats in Group B had a 20-Ga catheter placed in a femoral artery. In both groups, systolic, diastolic, and mean arterial pressures were directly measured using a validated pressure measurement system. Indirect values were compared against direct blood pressure measurements. RESULTS: There was no difference between groups. Overall, there was poor agreement with a significant bias observed between Doppler and directly measured blood pressures. For the systolic arterial pressure the bias was -8.8 with limits of agreements (LOA) of -39.3 and 21.7. For the mean arterial pressure, the bias was 14.0 with LOA of -13.9 and 41.9. For the diastolic arterial pressure, the bias was 27.9 with LOA of -4.4 and 60.2. Methodology, weight, sex, and replicates did not have a significant effect on the difference between indirect and direct measurements in any model. CONCLUSIONS: Results suggest poor agreement between Doppler values and directly measured blood pressures in anesthetized cats. Use of Doppler in cats could be misleading and readings should be interpreted with caution in a clinical context.

Evaluation of shock waveform configuration on the defibrillation capacity of implantable cardioverter defibrillators in dogs.

BACKGROUND: Implantable cardioverter defibrillators (ICD) are programmed to detect ventricular arrhythmias and terminate them by delivering an electrical shock. A defibrillation threshold (DFT) at least 10 J below the maximum device output is recommended for successful therapy. Shock waveform configuration is a programmable parameter used to achieve a low DFT. It is hypothesized that a fixed-pulse configuration results in lower defibrillation energy requirements than a fixed-tilt configuration. ANIMALS: 10 mongrel dogs. MATERIALS AND METHODS: ICD generator and transvenous lead were surgically implanted. Defibrillation threshold was determined using a protocol guided by the upper limit of vulnerability. Fixed-pulse and fixed-tilt (50%/50%) waveform configurations were tested in a random order. Plasma cardiac troponin I (cTnI) was measured for signs of myocardial injury. RESULTS: The experiment was completed in 9 dogs. Overall mean DFT value was 424 ± 88 V (9.2 ± 3.9 J). Mean differences among voltage, energy and impedance at the DFT for fixed-pulse (422 ± 97 V, 9.1 ± 4.2 J, 62.6 ± 13.8 Ω) and fixed-tilt (426 ± 83 V, 9.3 ± 3.8 J, 62.8 ± 18.5 Ω) configurations were not statistically significant (All P > 0.21). Cardiac TnI concentration changed from 0.03 ng/mL (95% CI: 0.02-0.04) at baseline to 0.11 ng/mL (95 CI: 0.08-0.16) after DFT was obtained with the first waveform configuration and 0.19 ng/mL (95% CI: 0.13-0.28) at the end of the study period. There were no significant changes in heart rate, end-tidal CO2 and blood pressure over time (all P > 0.09). CONCLUSION: The tested ICD device and lead placement reliably produced acceptable DFT values, based on a 10-J safety margin below the maximum device output. A benefit of fixed-pulse configuration could not be demonstrated over the standard fixed-tilt waveform. Signs of acute myocardial damage from repeated high-voltage shocks and episodes of ventricular fibrillation seemed of limited clinical significance.

Saline volume necessary to achieve predetermined intraluminal pressures during leak testing of small intestinal biopsy sites in the dog.

OBJECTIVE: To determine the volume of saline needed to achieve targeted intraluminal pressures during leak testing of closed jejunal biopsy sites in the dog. STUDY DESIGN: Experimental. ANIMALS: Dogs (n=38). METHODS: Jejunal biopsies in dogs were performed and closed using 3-4 full thickness simple interrupted sutures. Saline volumes needed to achieve 2 predetermined intraluminal pressures (20 and 34 cm water [15 and 25 mmHg]) in a 10 cm canine jejunal segment containing a closed biopsy site using 2 methods of luminal occlusion were recorded. RESULTS: The 95% confidence intervals for the volume of saline needed to achieve 20 and 34 cm water intraluminal pressure were 10.9-13.6 and 16.3-19.0 mL, respectively with digital occlusion and 8.5-11.1 and 12.1-14.8 mL, respectively with Doyen occlusion. Correlation between volume of saline instilled and the pressure achieved was 0.76 for digital occlusion and 0.86 for Doyen occlusion. CONCLUSION: Correlation between volume of saline instilled and pressure achieved was greater with Doyen than digital occlusion. CLINICAL RELEVANCE: For canine jejunum, saline volumes of 16.3-19 mL (digital occlusion) and 12.1-14.8 mL (Doyen occlusion) can be used to achieve intraluminal pressures of 34 cm water during leak testing of a 10 cm segment containing a closed biopsy site.

Differential expression of receptor tyrosine kinases (RTKs) and IGF-I pathway activation in human uterine leiomyomas.

Uterine leiomyomas (fibroids) are benign tumors that are prevalent in women of reproductive age. Research suggests that activated receptor tyrosine kinases (RTKs) play an important role in the enhanced proliferation observed in fibroids. In this study, a phospho-RTK array technique was used to detect RTK activity in leiomyomas compared with myometrial tissue. We found that fifteen out of seventeen RTKs evaluated in this study were highly expressed (P < 0.02-0.03) in the leiomyomas, and included the IGF-I/IGF-IR, EGF/EGFR, FGF/FGF-R, HGF/HGF-R, and PDGF/PDGF-R gene families. Due to the higher protein levels of IGF-IR observed in leiomyomas by us in earlier studies, we decided to focus on the activation of the IGF-IR, its downstream effectors, and MAPKp44/42 to confirm our earlier findings; and validate the significance of the increased IGF-IR phosphorylation observed by RTK array analysis in this study. We used immunolocalization, western blot, or immunoprecipitation studies and confirmed that leiomyomas overexpressed IGF-IRbeta and phosphorylated IGF-IRbeta. Additionally, we showed that the downstream effectors, Shc, Grb2, and MAPKp44/42 (P < 0.02-0.001) were also overexpressed and involved in IGF-IR signaling in these tumors, while IRS-I, PI3K, and AKT were not. In vitro studies showed that IGF-I (100 ng/mL) increased the proliferation of uterine leiomyoma cells (UtLM) (P < 0.0001), and that phosphorylated IGF-IRbeta, Shc, and MAPKp44/42 were also overexpressed in IGF-I-treated UtLM cells (P < 0.05), similar to the tissue findings. A neutralizing antibody against the IGF-IRbeta blocked these effects. These data indicate that overexpression of RTKs and, in particular, activation of the IGF-IR signaling pathway through Shc/Grb2/MAPK are important in mediating uterine leiomyoma growth. These data may provide new anti-tumor targets for noninvasive treatment of fibroids.

Localization of the sulfate/anion exchanger in the rat liver.

Although the sulfate/anion transporter (sat-1; SLC26A1) was isolated from a rat liver cDNA library by expression cloning, localization of sat-1 within the liver and its contribution to the transport of sulfate and organo sulfates have remained unresolved. In situ hybridization and immunohistochemical studies were undertaken to demonstrate the localization of sat-1 in liver tissue. RT-PCR studies on isolated hepatocytes and liver endothelial and stellate cells in culture were performed to test for the presence of sat-1 in these cells. In sulfate uptake and efflux experiments, the substrate specificity of sat-1 was evaluated. Sat-1 mRNA was found in hepatocytes and endothelial cells. Sat-1 protein was localized in sinusoidal membranes and along the borders of hepatocytes. The canalicular region and bile capillaries were not stained. Sulfate uptake was only slightly affected by sulfamoyl diuretics or organo sulfates. Sulfate efflux from sat-1-expressing oocytes was enhanced in the presence of bicarbonate, indicating sulfate/bicarbonate exchange. Estrone sulfate was not transported by sat-1. Sat-1 may be responsible for the uptake of inorganic sulfate from the blood into hepatocytes to enable sulfation reactions. In hepatocytes and endothelial cells, sat-1 may also supply sulfate for proteoglycan synthesis.

Treatment of genotype 2 and 3 chronic hepatitis C virus-infected patients.

AIM: Before pegylated interferon alpha (IFN) was introduced for the therapy of chronic hepatitis C virus (HCV)-induced hepatitis, conventional thrice weekly IFN therapy was supplemented by ribavirin. Also, at that time, higher and more frequent doses of IFN were expected to be more effective than the standard regimen of 3 MU thrice weekly. As ribavirin significantly increases side effects and negatively influences the quality of life particularly in young patients, we started a prospective non-randomized study with a daily IFN-2a monotherapy as an initial treatment for chronic hepatitis C. METHODS: Forty-six consecutive chronic HCV-infected patients received 3 MU IFN-2a per day as an initial treatment. Patients with genotype 2 or 3 (n = 12) were treated for 24 wk, and patients with genotypes other than 2 or 3 (n = 34) for 48 wk. Treatment outcome was followed up for 48 wk after the end of treatment (EOT). Virological response was defined as the absence of detectable serum HCV-RNA. Patients without virological response at 12 wk after the start of treatment received low-dose ribavirin (10 mg(kg/d)) additionally. RESULTS: During treatment, three genotype 3 patients were excluded from the study due to incompliance. The remaining patients (n = 9) infected with genotype 2 or 3 showed an initial virological response rate of 100%. Six patients (66.7%) were still found to be virus-free at the end of follow-up period. In these patients, initial virological response was evident already after 2 wk of treatment. In contrast, initial virological response occurred first after 4 wk of treatment in the three patients who relapsed (33.3%). In comparison, patients infected with genotypes other than 2 or 3 (n = 34) showed an initial virological response rate of only 23.5% (n = 8), and even in combination with ribavirin a sustained virological response (SVR) rate of only 11.8% (n = 4) could be achieved. CONCLUSION: In chronic HCV-infected patients with genotype 2 or 3, a SVR can be expected after 24 wk of daily dose IFN-2a treatment without ribavirin, if initial virological response develops early. This finding is worth to be confirmed in a prospective randomized study with pegylated IFN.

Irradiation leads to susceptibility of hepatocytes to TNF-alpha mediated apoptosis.

BACKGROUND AND PURPOSE: The pathogenesis of radiation-induced-liver-disease (RILD) is still unknown. We tested the hypothesis that irradiated liver macrophages influence the viability of radiation stressed hepatocytes. PATIENTS AND METHODS: Hepatocytes and liver macrophages were isolated from rat liver, cultured and irradiated with doses of 2, 8, and 25 Gy. Cell viability was measured by trypan blue exclusion, and by annexin V/propidium iodide staining. TNF-alpha in the supernatants from liver macrophage cell culture was quantitatively detected by ELISA. TNF-alpha mRNA from liver macrophages was measured by real time PCR. RESULTS: Irradiation had no influence on cell viability. Apoptosis of irradiated hepatocytes was detected 24h after replacing 50% of medium with supernatants of irradiated liver macrophages 6 h after irradiation (32.0+/-5.8% compared to solely irradiated cells (12+/-2.9%, P=0.02)). In supernatants of hepatocytes, no TNF-alpha secretion could be measured. A radiation dependent increase was found in supernatants of liver macrophages. Addition of anti-TNF-alpha-antibodies to the supernatants of irradiated liver macrophages reduced apoptosis (20+/-0.9%). Incubation of irradiated hepatocytes with purified recombinant TNF-alpha increased apoptosis in irradiated hepatocytes. This effect could be abrogated by additional administration of TNF-alpha-antibodies. CONCLUSIONS: Irradiation leads to susceptibility of hepatocytes to TNF-alpha mediated apoptosis. Liver macrophages may be one of the sources of TNF-alpha in case of liver-irradiation. This cell-cell-interaction may be an important initial step towards RILD and liver fibrosis.