Influence of bacteria isolated from rice plants and rhizospheres on antibiotic production by the antagonistic bacterium <Emphasis Type="Italic">Serratia marcescens</Emphasis> strain B2

Serratia marcescens strain B2 is an antagonistic bacterium that produces the red-pigmented antibiotic prodigiosin and suppresses rice sheath blight caused by Rhizoctonia solani AG-1 IA. Rice sheath blight disease was suppressed when plants were inoculated with this bacterium an hour before pathogen inoculation but not when plants were treated 4 weeks before pathogen inoculation. In both cases the bacteria were detected in the rice rhizosphere 4 weeks after inoculation. Bacteria isolated from the rice plant and rhizosphere inhibited biosynthesis of prodigiosin in S. marcescens strain B2. We suggest that bacteria isolated from rice plants and rhizospheres mediate the suppression of antibiotic production of biological control agents and that such suppression is common under field conditions.     

The nutritional needs of a continuous passage horse leucocyte culture

The addition of three amino acids (arginine, cystine and histidine) to existing common media prevented spontneous degeneration in a continuous passage horse leucocyte cell culture. The type of degeneration was the same for each of the amino acids previously described for the HeLa cell.     

Effects of light conditions on prodigiosin stability in the biocontrol bacterium Serratia marcescens strain B2

Serratia marcescens strain B2 is a potential biocontrol agent that produces the antibiotic pigment prodigiosin. When this strain was incubated under white or blue light conditions (<100µmol m^–2s^–1), prodigiosin concentration in bacterial cells decreased, but growth did not. However, red and far-red light had no effect on prodigiosin concentration in bacterial cells. Purified prodigiosin was degraded under white or blue light conditions but was not degraded under red and far-red light. Because white and blue light appeared to affect the stability of prodigiosin itself, light conditions may affect the suppressive effects of the biocontrol agent S. marcescens strain B2.     

A case of gastrinoma in a Shih-Tzu dog

A five-year-old male Shih-Tzu dog presented with severe vomiting and weight loss. The clinical signs were successfully improved by an eight-day treatment with an H(2)-receptor antagonist, gastrointestinal protectant and antibiotics. Ten days later, however, recurrence of vomiting was seen despite continuous medical treatment. Based on clinical signs and the results of various diagnostic tests including CBC, biochemical analysis, contrast radiography, and endoscopy, a duodenal or pancreatic neoplasm was suspected and exploratory laparotomy was conducted. Some swollen pancreatic regions were found, and biopsy of the pancreas indicated the diagnosis of a gastrin-secreting tumor. Consequently, based on a high serum gastrin level as well as clinical signs and immunohistological findings, we diagnosed the disease as canine gastrinoma, a rare tumor of the pancreas.     

Relationships between velocities of pulmonary venous flow and plasma concentrations of atrial natriuretic peptide in healthy dogs

OBJECTIVE: To investigate the relationship between velocities of pulmonary venous flow (PVF) and plasma concentrations of atrial natriuretic peptide (ANP) in healthy dogs. ANIMALS: 7 healthy Beagles. PROCEDURES: Dogs were anesthetized, intubated, and positioned in left lateral recumbency. Lactated Ringer's solution was infused (200 mL/kg/h) for 60 minutes via a cephalic vein. Transmitral flow and PVF velocities were measured echocardiographically by use of the apical 4-chamber view. Pulmonary capillary wedge pressure (PCWP) and ANP concentrations were determined. RESULTS: IV infusion significantly increased heart rate and PCWP. Similarly, the ANP concentration significantly increased from baseline (before infusion of lactated Ringer's solution) values. Transmitral flow velocities were significantly increased, although the ratio of velocity of the flow during early ventricular diastole (E wave) to velocity of the atrial flow (A wave; E:A ratio) was unchanged. Regarding the PVF velocities, forward flow during ventricular systole (S wave) and retrograde flow during atrial contraction were significantly increased, whereas velocity of the forward flow during ventricular diastole (D wave) was unchanged. Ratio of the velocity of the S wave to velocity of the D wave was increased significantly, and this ratio was significantly correlated with PCWP or ANP concentration. However, the E:A ratio was not correlated with PCWP or ANP concentration. CONCLUSIONS AND CLINICAL RELEVANCE: PVF velocities were strongly correlated with PCWP and plasma ANP concentration in clinically normal dogs. Therefore, PVF velocities may serve as a sensitive indicator and provide additional information for monitoring acute preloading conditions and estimating atrial filling abnormalities in dogs.     

ACVIM consensus guidelines for the diagnosis and treatment of myxomatous mitral valve disease in dogs

This report, issued by the ACVIM Specialty of Cardiology consensus panel, revises guidelines for the diagnosis and treatment of myxomatous mitral valve disease (MMVD, also known as endocardiosis and degenerative or chronic valvular heart disease) in dogs, originally published in 2009. Updates were made to diagnostic, as well as medical, surgical, and dietary treatment recommendations. The strength of these recommendations was based on both the quantity and quality of available evidence supporting diagnostic and therapeutic decisions. Management of MMVD before the onset of clinical signs of heart failure has changed substantially compared with the 2009 guidelines, and new strategies to diagnose and treat advanced heart failure and pulmonary hypertension are reviewed.     

Corneal squamous cell carcinoma in two dogs

Purpose To report two cases of corneal squamous cell carcinoma (SCC) in dogs. Methods Corneal tumors were resected by superficial keratectomy in two cases. Immunohistochemistry of the corneal tissues was performed using anti‐p53 antibody. Results The prominent features of the cases were a clinical history of pigmentary keratitis and chronic keratitis. In each case, a corneal mass was surgically removed with a superficial keratectomy and histologically diagnosed as corneal SCC. Both masses were negative for p53. To reduce chronic corneal irritation, 0.1% hyaluronate sodium ophthalmic solution was applied. After more than 15 months of postsurgical follow‐up there has been no recurrence of either neoplasm. Conclusion and discussion Chronic corneal irritation was suspected as the primary etiology for the corneal SCC. Appropriate surgical removal of the mass and subsequent conservative treatment for keratitis provided effective therapy in these two cases.     

Establishment of an Invasive Prostate Cancer Model in Transgenic Rats by Intermittent Testosterone Administration

We have established a transgenic rat for adenocarcinoma of the prostate (TRAP) model that features uniform adenocarcinoma development in prostatic lobes at high incidence within a short experimental period. However, no invasive carcinomas with reactive stroma characteristics similar to those in man were observed. We therefore have focused on a new model for invasive carcinoma of the prostate using TRAP rats. In experiment 1, male TRAP rats in groups 1 and 2 were treated with orchiectomy at day 0 of the experiment. Rats in groups 1–3 underwent testosterone propionate (TP) implantation from weeks 1 to 4 and from weeks 6 to 16. Rats in groups 1 and 3 were given 3,2’-dimethyl-4-aminobiphenyl (DMAB) after TP implantation. The rats of group 4 served as controls. In experiment 2, the rats were divided into three groups, none of which received DMAB or orchiectomy, treated with TP continuously or with the treatment withdrawn once or twice. In experiment 1, invasive adenocarcinomas with abundant collagenous stroma were found in the dorsolateral and anterior prostate, some of which showed perineural space invasion at week 16. The number of invasive carcinoma foci was most frequent in group 3. In experiment 2, invasive adenocarcinoma development in the lateral prostates was correlated with the number of TP administration/withdrawal cycles. In conclusion, our newly established rat model for invasive adenocarcinoma of the prostate could serve as a useful preclinical model for evaluating the in vivo efficacy of preventive and therapeutic agents targeting of the tumor microenvironment.