Post-mortem evaluation of expanded polytetrafluoroethylene (ePTFE) used in mitral valve repair in dogs

Mitral valve repair is one of the treatment options for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) is a polymer that has been widely used in cardiovascular surgery. In this case series, we report the autopsy and histological findings in 6 dogs that underwent cardiopulmonary bypass for mitral annuloplasty using ePTFE sheets and chordoplasty using ePTFE sutures.From May 2005 to October 2009, 3 female and 3 male dogs with severe mitral regurgitation underwent mitral valve repair. This case series included 3 Cavalier King Charles spaniels, 2 Maltese, and 1 Shih Tzu. The survival period after surgery was 19–72 (35 ± 19) months.In all the cases, autopsy revealed that the ePTFE sheets and sutures were not damaged and well integrated into the surrounding highly differentiated, connective tissues. Low-power microscopy revealed that in all cases, the tissues surrounding the ePTFE sheet in the mitral valve annulus had almost completely been covered by granulation tissue. No inflammatory infiltrate or thrombogenesis was observed around the ePTFE in any of the cases.There was no evidence of reactive changes in the region surrounding the ePTFE. These results suggest that ePTFE has excellent tissue compatibility and durability and can be effectively used for canine mitral valve repair.     

Control of clubroot of crucifers by Phoma glomerata and its product epoxydon

Phoma glomerata strain JCM9972 controls clubroot of cruciferous crops caused by Plasmodiophora brassicae and the activity depends upon epoxydon (5-hydroxy-3-(hydroxymethyl)-7-oxabicyclo [4.1.0]hept-3-en-2-one) produced by the strain.     

Effects of bovine lactoferrin by the intramammary infusion in cows with staphylococcal mastitis during the early non-lactating period

To evaluate the clinical effects of bovine lactoferrin on staphylococcal mastitis in Holstein cows during the early non-lactating period, 41 mammary quarters were selected randomly from 36 cows on 3 dairy farms. Twelve quarters were infused intramammarily with bovine lactoferrin. Twenty-nine quarters were infused with antibiotic as a control. In the bovine lactoferrin-infused group, 91.7% of mastitic quarters were cured at 7 days after calving, compared with 48.3% in the control group. Furthermore, the changes in mammary secretion induced by the infusion of bovine lactoferrin were investigated. Mean numbers of staphylococci in mammary gland secretions were significantly decreased in both 5 bovine lactoferrin-infused quarters and 5 antibiotic-infused control quarters (p<0.05). Unlike in the control quarters, the mean total cell concentration in the mammary gland secretions increased in bovine lactoferrin-infused quarters. Similar results were obtained in 6 healthy quarters which were infused with bovine lactoferrin. In these quarters, the cell population contained mainly phagocytes such as polymorphonuclear leukocytes and cells positive for CD11b which is known as a complement receptor. The mean concentration of C3 in mammary gland secretions was significantly increased in 5 mastitic quarters infused with bovine lactoferrin (p<0.05), but showed no significant change in 5 mastitic control quarters. These results suggested that bovine lactoferrin treatment for staphylococcal mastitis in the early non-lactating period might increase the rate of cure through the induction of innate immunity in the host.     

p27(Kip1) negatively regulates the activation of murine primordial oocytes

In mice, small oocytes (primordial oocytes) are enclosed within flattened granulosa cells to form primordial follicles around birth. A small number of primordial oocytes enter the growth phase, whereas others are quiescent. The mechanism regulating this selection of primordial oocytes is not well understood. The objective of the present study was to understand the role of p27(Kip1), which regulates cell cycle progression in somatic cells, in the growth initiation of primordial oocytes in neonatal mice. We studied the localization of p27(Kip1) in 0-, 3-, 5-, 7- and 21-day-old mouse ovaries by immunohistochemistry. Ovaries from 3-day-old mice were treated with p27(Kip1) siRNAs (small interfering RNAs), and knockdown of p27(Kip1) was determined by immunohistochemistry and Western blotting. Ovaries treated with siRNAs were organ-cultured for 6 days, and oocyte growth was estimated histologically. Expression of p27(Kip1) was undetectable in the primordial oocytes of newborn mice. In the 3-day-old ovaries (n=3), p27(Kip1) was demonstrated in the nucleus of 36 ± 6% primordial oocytes. The percentage of p27(Kip1)-positive primordial oocytes increased to 72 ± 8 (n=3), 85 ± 7 (n=3) and 93 ± 5 (n=3) in the 5-, 7- and 21-day-old mouse ovaries, respectively. After knockdown of the p27(Kip1) protein by siRNAs, a higher proportion of oocytes entered the growth phase in cultured ovaries than those in the control. These results suggest that p27(Kip1) negatively regulates primordial oocyte growth and that knockdown of p27(Kip1) leads primordial oocytes to enter the growth phase in vitro.     

The canine RAD51 mutation leads to the attenuation of interaction with PALB2

RAD51 forms a complex with BRCA2 and plays a central role in the DNA damage response pathway that is associated with homologous recombination. The structures of RAD51 and its homologues are highly conserved from prokaryotes to higher eukaryotes. Although a large number of BRCA2 mutations have been reported, there are only a few reports on the mutations of RAD51, which have been shown in humans and dogs. However, several mutations of canine RAD51 were identified from mammary gland tumour tissues in a recent study. Some of these mutations seem to have an influence on the homo‐oligomerization or interaction with “Partner and localizer of BRCA2” (PALB2). In this study, we cloned the canine PALB2 homologue and investigated the effect on its interaction with the RAD51 mutants to evaluate the alteration in the function of RAD51 mutants. The A209S and T225S mutants of RAD51 show an attenuation of the interaction between RAD51 and PALB2. These results indicate that the canine RAD51 mutations can potentially alter the homologous recombination pathways in response to DNA damage in dogs.     

Persorption of bovine lactoferrin from the intestinal lumen into the systemic circulation via the portal vein and the mesenteric lymphatics in growing pigs

The absorption and the transportation of intestinally administrated bovine lactoferrin (LF) were immunohistochemically and physiochemically investigated in the small intestine of growing pigs. At the apical halves of the small intestinal villi, bovine LF was absorbed by transcytosis as small vesicles through villous columnar epithelial cells. The presence of bovine LF-positive membranes of transcytotic vesicles suggests that the absorption was mediated by LF-binding factors on the epithelial cell membranes. Almost all of the absorbed bovine LF was demonstrated to be transported via the lymphatics and the portal vein into the systemic circulation. The LF-concentration in systemic circulation was significantly higher at 1 hr following intestinal administration of bovine LF. Bovine LF-positive lymphocytes also were transferred into the systemic circulation from intestine via the lymphatics and the portal vein.     

Swim bladder tumor in the young adult scoliotic medaka (Oryzias latipes)

A swim bladder tumor was detected in one scoliotic medaka aged 22 weeks. The tumor was located in the dorsal abdominal cavity, with maximum dimension of 1,850 × 1,500 µm. No swim bladder lumen was identified, and the region where the swim bladder lumen would have been located, was replaced with adipose tissues. The tumor was a non-invasive, expansile, and encapsulated solid mass with a few cysts, and comprised a homogenous population of well-differentiated, densely packed, gas glandular epithelium-like cells. The tumor mass was connected to a rete mirabile that showed a hyperplastic capillary plexus; however, the tumor cells did not invade the rete mirabile, thereby revealing that the tumor was an adenoma originating from the gas glandular epithelium of the swim bladder. Since proliferative lesions in the swim bladder have been reported in some teleosts with skeletal deformations, including medaka, the occurrence of a spontaneous swim bladder tumor in teleosts is considered to be closely associated with various types of skeletal deformation, and spinal curvature in particular.     

Prognostic factors for dogs with surgically resected gastrointestinal stromal tumors

Few reports have investigated prognosis of canine gastrointestinal stromal tumor (GIST) cases treated by surgical resection alone. In the present study, we investigated the overall survival (OS) and prognostic factors for dogs with GIST treated by surgical complete resection alone. Fifty-three dogs were included, and the median OS was 18 months. Multivariate analysis showed that primary tumors in small intestine (P=0.04) is significantly associated with shorter OS, and median OS of the cases with cecum lesion and those with small intestine lesion was 22 and 6 months, respectively. The present study suggested primary tumor site was a novel prognostic factor for dogs with GIST treated by surgical complete resection alone.