Spontaneous urinary calculus in young LEW rats caused by Corynebacterium renale

Characterization of Corynebacterium species in macaques

Bacteria of the genus Corynebacterium are important primary and opportunistic pathogens. Many are zoonotic agents. In this report, phenotypic (API Coryne analysis), genetic (rpoB and 16S rRNA gene sequencing), and physical methods (MS) were used to distinguish the closely related diphtheroid species Corynebacterium ulcerans and Corynebacterium pseudotuberculosis, and to definitively diagnose Corynebacterium renale from cephalic implants of rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques used in cognitive neuroscience research. Throat and cephalic implant cultures yielded 85 isolates from 43 macaques. Identification by API Coryne yielded C. ulcerans (n = 74), Corynebacterium pseudotuberculosis (n = 2), C. renale or most closely related to C. renale (n = 3), and commensals and opportunists (n = 6). The two isolates identified as C. pseudotuberculosis by API Coryne required genetic and MS analysis for accurate characterization as C. ulcerans. Of three isolates identified as C. renale by 16S rRNA gene sequencing, only one could be confirmed as such by API Coryne, rpoB gene sequencing and MS. This study emphasizes the importance of adjunct methods in identification of coryneforms and is the first isolation of C. renale from cephalic implants in macaques.

Large animal models of fulminant hepatic failure in artificial and bioartificial liver support research

Among the large range of organs involved in the field of tissue engineering (skin, blood vessels, cartilage, etc.) the liver has been given broad attention in the last decade. Liver support systems encompassing artificial and bioartificial systems are applied to treat patients with fulminant hepatic failure (FHF) as a bridge to orthotopic liver transplantation or to liver regeneration. To test safety, technical applicability and therapeutic effect of liver support systems, reliable animal models are needed. Due to the complexity of FHF many diverse attempts have been made to develop an adequate animal model to study liver failure, liver regeneration and liver support systems. In this paper an overview is given of the different models and their advantages and disadvantages are discussed. Suggestions are made for the most suitable large animal model to test liver support systems.

Distribution of Corynebacterium renale among apparently healthy rats

We examined the distribution of Corynebacterium renale, a causative agent of urinary calculus, in clinically normal rats at 6 animal facilities in Japan. Swabs of the vulva and vaginal vestibule or prepuce of the rats were cultured for isolation of the organisms. C. renale has been isolated at only one animal facility, where cases of urinary calculus were reported several years ago. In this facility, 32% of female (43/135) and 22% of male (18/82) rats, 4-28 weeks old, were positive for C. renale. In contrast, 92 female and 169 male rats at other facilities without a history of the disease were negative for the organisms.

Regeneration of bladder urothelium, smooth muscle, blood vessels and nerves into an acellular tissue matrix

PURPOSE

To study the cellular events occurring during bladder development and regeneration we developed an in vivo model of bladder augmentation with an acellular tissue graft. We propose that the extracellular matrix orchestrates the regenerative capacity of host bladder cells (urothelium, smooth muscle, blood vessels and nerve cells) after bladder augmentation with acellular tissue matrix.

MATERIALS AND METHODS

A total of 40 adult rats underwent partial cystectomy and augmentation with a patch of extracellular matrix representing the full thickness of rat gastric or bladder tissue. Sections were examined histologically to assess urothelial, smooth muscle and neuronal invasion of the graft.

RESULTS

A total of 32 rats was evaluated 1 day to 26 weeks after grafting. Epithelialization occurred by day 4, accompanied by granulocytic infiltration. Smooth muscle regenerated 2 weeks after grafting in juxtaposition to epithelial surfaces and it matured into normal sized bundles by 26 weeks. Neovascularity was noted 2 weeks postoperatively. Neural elements formed around developing smooth muscle bundles as early as 4 weeks after grafting.

CONCLUSIONS

We demonstrated the regeneration of urothelium, smooth muscle, blood vessels and nerves within a full thickness grafted acellular tissue matrix scaffold in the rat. The spatial orientation of these elements suggests that mesenchymal-epithelial interactions occur during phenotypic regeneration of the bladder. Urothelium appears to regulate the early forming smooth muscle. This in vivo model provides a suitable method to study cellular events during regeneration.