Morphological, Cultural, Biochemical, and Serological Comparison of Japanese Strains of Vibrio parahemolyticus with Related Cultures Isolated in the United States

Morphological, cultural, biochemical, and serological characteristics of 79 strains of Vibrio parahemolyticus isolated from patients suffering from gastroenteric disease in Japan were compared with 17 suspected V. parahemolyticus cultures isolated from wound infections and 14 nonpathogenic vibrios isolated from an estuarine environment in the United States. These groups were differentiated on the basis of several key reactions which included: the range of growth temperature and salt tolerance; the production of catalase and acetoin; the hydrolysis of starch; the fermentation and utilization as single carbon source of sucrose, cellobiose, and arabinose; and the ability to swarm on 1% agar. The separation of the groups on the basis of cultural and biochemical analyses was confirmed by means of slide agglutinations with specific anti-K antisera. The results of this study strongly suggest that the wound infection isolates are V. parahemolyticus species which are easily distinguished from the nonpathogenic estuarine vibrios.     

The effects of methyltestosteone on reproductive function in male greyhounds

Oral administration of methyltestosterone (MT) at 50 mg/dog/day to intact adult male greyhounds for 90 d resulted in decreased (P < 0.05) mean daily sperm output and mean testicular length. Additionally, the mean diameter of seminiferous tubules in MT-treated dogs tended to decrease (P = 0.08). Mean concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) and concentrations of testosterone in serum were also decreased or tended to decrease (P = 0.0003 to 0.059) at various sampling periods during MT treatment, suggesting alterations in spermatogenesis resulted from decreased serum concentrations of gonadotropins and steroids. Mean daily sperm output, mean testicular length, mean seminiferous tubule diameter and mean concentrations of FSH in serum were not decreased (P > 0.05) at the end of a 90-d recovery period. However, mean concentrations of serum LH and concentrations of testosterone were still lower (P < 0.05) during five of six and one of six sampling times, respectively, during the recovery period than the pretreatment levels, suggesting a prolonged effect of MT treatment on the pituitary/gonadal axis.     

Comparison of NK-1 Receptor Antagonist (Maropitant) to Morphine as a Pre-Anaesthetic Agent for Canine Ovariohysterectomy

Objective

To compare the NK-1 receptor antagonist maropitant to morphine during and after surgery in dogs undergoing ovariohysterectomy (OHE).

Methods

30 healthy female dogs were randomly divided to receive either a pre-anaesthetic dose of morphine (0.5 mg/kg SQ) or maropitant (1 mg/kg, SQ) prior to OHE. Anaesthesia was induced with propofol and maintained with isoflurane. Expired isoflurane concentration, heart rate (HR), systolic arterial pressure (SAP) and respiratory rate were measured. Post-operative pain scores and appetite were evaluated during the recovery period. Rescue analgesia (morphine 0.1 mg/kg IV) was administered as needed post-operatively based on blinded pain score assessments.

Results

Although clinically comparable; during surgical stimulation, the maropitant group had lower HR (108±18 vs 115±24 bpm; p = 0.04), lower SAP (114±23 vs 125±23 mmHg; p = 0.003) and required slightly lower percent of isoflurane anaesthetic (1.35±0.2 vs 1.51±0.4%; p = 0.005), when compared to the morphine group. In the recovery period, the maropitant group had lower pain scores at extubation (1.7±0.7 vs 3.4±2.3; p = 0.0001) and were more likely to eat within 3 hours after extubation (64.7 vs 15.3%). However, post-operative rescue analgesia requirements were similar between groups. All other measured parameters were similar between groups. The overall difference observed between groups was small and all monitored and measured parameters were within the expected range for anesthetized dogs.

Clinical Significance

No major differences in cardiorespiratory parameters or anaesthetic requirements were observed between maropitant and morphine when used as a pre-anesthetic agent for OHE. Further studies are necessary to fully elucidate the benefits of maropitant as a pre-anaesthetic agent for canine OHE.     

Thermal inactivation of ileal loop-reactive Clostridium perfringens type A strains in phosphate buffer and beef gravy.

The thermal resistance of spore crops produced from each of two ileal loop-reactive strains of Clostridium perfringens type A was determined in two suspending vehicles consisting of 0.067 M (pH 7.0) phosphate buffer and a commercial beef gravy. D115.6 values obtained in buffer and enumerated after pretreatment with sodium ethylenediaminetetraacetate and recovery in plating medium containing lysozyme were two- to threefold greater than those obtained without this treatment. D115.6 values obtained with beef gravy were less than those obtained in buffer with or without lysozyme; however, the D98.9 and D104.4 values were 1.3 to 2 times greater than those obtained in buffer with lysozyme. The z values were within the ranges reported by previous investigators.     

Wnt-5/pipetail functions in vertebrate axis formation as a negative regulator of Wnt/beta-catenin activity

We provide genetic evidence defining a role for noncanonical Wnt function in vertebrate axis formation. In zebrafish, misexpression of Wnt-4, -5, and -11 stimulates calcium (Ca2+) release, defining the Wnt/Ca2+ class. We describe genetic interaction between two Wnt/Ca2+ members, Wnt-5 (pipetail) and Wnt-11 (silberblick), and a reduction of Ca2+ release in Wnt-5/pipetail. Embryos genetically depleted of both maternal and zygotic Wnt-5 product exhibit cell movement defects as well as hyperdorsalization and axis-duplication phenotypes. The dorsalized phenotypes result from increased beta-catenin accumulation and activation of downstream genes. The Wnt-5 loss-of-function defect is consistent with Ca2+ modulation having an antagonistic interaction with Wnt/beta-catenin signaling.     

Enteropathogenicity of Vibrio parahaemolyticus in the ligated rabbit ileum.

The enteropathogenicity of Vibrio parahaemolyticus was investigated by contrasting the effects of whole cells, cell fragments, cell-free preparations, and media constituents injected into rabbit ileal loops. Three of 20 cultures utilized were Kanagawa-negative strains from seawater and sea fish. The remaining 17 cultures included both Kanagawa-positive and -negative strains from Japanese victims of gastroenteritis. Broth culture filtrates concentrated 10-fold by dialysis against 30% Carbowax were unreactive, whereas lyophilized filtrates, regardless of Kanagawa type, as well as all sterile broth preparations containing greater than or equal to 5% NaCl gave positive reactions in the rabbit gut. In contrast, crude lysates derived from broth cultures of Kanagawa-positive strains caused loop dilatation; lysate supernatants were unreactive. Lysates of cells washed from brain heart infusion agar were more reactive than lysates from Trypticase soy agar-grown cells. When agar-grown cell lysates prepared by disruption in saline were dialyzed against distilled water, they were devoid of gut reactivity. Reactivity was restored in dialysands resuspended in saline and in dialysates concentrated 10-fold. The agar-grown cell lysates exhibited Kanagawa-type hemolysis. Our data support the conclusion that the rabbit loop reactivity observed with lyophilized, cell-free culture filtrates may result from excessively elevated NaCl concentrations, and that a toxic factor associated with large-cell particles may be dialyzable, depends on saline for expression, and resembles the Kanagawa hemolysin.     

Isolation of an enteropathogenic, Kanagawa-positive strain of Vibrio parahaemolyticus from seafood implicated in acute gastroenteritis.

A strain of Vibrio parahaemolyticus, serotype O4/K4, that was Kanagawa positive and reactive in the rabbit ileal loop test, was isolated in low numbers from raw oysters implicated in a case of acute gastroenteritis. To our knowledge, this is the first report of the isolation of a Kanagawa-positive strain from suspect food in the United States.     

Demonstration of invasiveness of Vibrio parahaemolyticus in adult rabbits by immunofluorescence.

To determine possible pathogenesis of Vibrio parahaemolyticus-host-organ system interactions, studies of invasiveness were made by a direct fluorescent-antibody method. Broth cultures of live cells isolated from seafish or symptomatic humans were inoculated separately into ligated ileal loops of young New Zealand white rabbits. After suitable incubation, rabbits were sacrificed, and ileal loops and tissue specimens were aseptically removed. Ileal loops were prepared and stained with specific fluorescein-tagged antibody, and organ specimens were cultured for isolation of the inoculated Vibrio strain. All strains tested penetrated into the lamina propria of the ileum and were isolated from the cultured tissue specimens, indicating that the organism is capable of more than a superficial colonization of the gut. The presence of Vibrio in cultured tissue specimens suggests invasion of deeper tissue by either the lymphatic or the circulatory system.     

Effective ileal loop dose of Kanagawa-positive Vibrio parahaemolyticus.

Groups of 16 rabbits per strain were injected with broth culture dilutions of three Kanagawa-positive Vibrio parahaemolyticus strains. The effective dose required to produce ileal loop dilatation in 50% of rabbits for pure cultures of strains 10136-76 and 553-72 from patients stools and NY 477 from incriminated food was 1.1 x 10(6), 2.6 x 10(5), and 7.7 x 10(6) organisms, respectively. When each of these cultures was admixed with greater than or equal to 10(9) Vibrio alginolyticus cells, the 50% effective dose was 1.2 x 10(6), 1.1 x 10(7), and 1.3 x 10(8) cells, respectively. Although concomitant injection of large numbers of competitive nonvirulent cells did not affect the 50% effective dose for strain 10136-76, that for the remaining two was increased 20- to 40-fold. The initiation of ileal loop response as estimated from sigmoidal plots of proportion of positive loops versus cell concentrations was given by as few as 10(2) cells of strain 553-72. Strains NY 477 and 10136-76 required approximately 10(5) cells. Half of the maximal response from these plots corresponded well with the 50% effective dose for the strains. These results suggest that pathogenicity of Kanagawa-positive V. parahaemolyticus strains may involve the participation of some virulence mechanisms in addition to the Kanagawa hemolysin.     

Rapid Method for Detection and Enumeration of Fecal Coliforms in Fresh Chicken

A rapid method for enumerating fecal coliforms in foods was developed employing an agar pour-plate medium. After 7 h of incubation at 41.5 +/- 0.05 C, this medium effectively allows the growth of fecal coliforms only. This rapid method was compared with the Association of Official Analytical Chemists multiple-tube dilution method for Escherichia coli, by using 21 samples of fresh, cut-up chicken and a surface rinsing procedure for sample preparation. Verification of picked colonies was carried out in EC broth using parallel incubation temperatures of 45.5 and 44.5 +/- 0.05 C. Verifications for these temperatures averaged 79 and 98%, respectively. All positively verified isolates were E. coli types I and II, as were the negatives. Geometric means for the verified 7-h plate count were within 12% of the standard means for both EC broth incubation temperatures.