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Biomedical subjects

N Kirchhof

Publications and source records attributed to N Kirchhof.

9 recordsLinked to original sources
PubMed1998

Posttransplant nonfunction of canine islets in PVG rats deficient in complement component C6.

BACKGROUND: Discordant islet xenografts are immediately nonfunctional in nonimmunosuppressed recipients other than the mouse, a process called primary nonfunction. Although at present it is unknown whether complement is involved, complement might participate in the induction of primary nonfunction through a number of mechanisms. We investigated the potential role of the membrane attack complex of complement in primary nonfunction of transplanted xenoislets. METHODS: Canine islets were transplanted into both nonimmunosuppressed and immunosuppressed normocomplementemic and C6-deficient (C6D) PVG rats. Cyclosporine, rapamycin, deoxyspergualin, and mycophenolate mofetil were used for immunosuppression from day -3 to cessation of islet cell function. Serum glucose was measured at 6 hr after transplant and daily thereafter. Xenograft tissue sections were obtained at various times after transplant and stained for inflammatory cells and insulin. RESULTS: Canine islets grafted in nonimmunosuppressed C6D rats and normocomplementemic rats underwent primary nonfunction in all animals. The incidence of primary nonfunction in animals receiving a four-drug immunosuppressive regimen was 33% in the normocomplementemic rats but only 10% in the C6D rats. The mean functional islet survival time was 1.57+/-0.33 days in the normocomplementemic group and 2.70+/-0.67 days in the C6D group (P=0.38). The islet xenografts showed little difference in degree and composition of cell infiltration between normocomplementemic and C6D rats. CONCLUSION: The membrane attack complex does not appear to play a major role in primary nonfunction of canine islet xenografts in nonimmunosuppressed PVG rats. However, there was a lower incidence of primary nonfunction and a longer posttransplant survival time in immunosuppressed C6D rats, suggesting the membrane attack complex may play a minor role in recipients that are heavily immunosuppressed.

Animals↗
PubMed1996

Equine adenocarcinomas of the large intestine with osseous metaplasia.

Large intestinal adenocarcinoma with osseous metaplasia was diagnosed in two horses, a 15-year-old standard bred gelding and a 9-year-old Haflinger mare. Clinically, both animals had displayed weight loss and anaemia. A presumptive diagnosis of abdominal neoplasia was made and the horses were humanely killed. At necropsy, the gelding and the mare were found to have ulcerated tumours growing into the lumen of the caecum and colon, respectively. In the mare, the mass extended through the mesocolon and was evident in the left dorsal and ventral colon. Histopathologically, the tumours consisted of well-differentiated cords of single-layered columnar to cuboidal epithelial cells. Mitotic figures were very uncommon. In both lesions, well-formed bony spicules and osteoid were present in the fibrovascular stroma. The tumours were well-demarcated from surrounding mucosal tissue but had invaded the intestinal wall. Metastases were not observed.

Adenocarcinoma↗
PubMed1996

Multiple peripheral nerve sheath tumors in the small intestine of a horse.

Multiple neurofibromas, schwannomas, and hyperplastic enteric plexuses were observed in the distal jejunum and ileum of a 6-year-old pinto gelding. The animal was presented because of an acute episode of colic. Three meters of distal small intestine, partially incarcerated in the epiploic foramen, were surgically removed. Numerous tumor nodules up to 10 mm in diameter were found adjacent to a Meckel's diverticulum, predominantly located in the subserosa of a hypertrophic segment. Histologically, tumors were well demarcated and composed of interlacing fascicles formed by spindloid cells. Adjacent enteric plexuses were hyperplastic. Immunohistochemically, all tumors were positive for vimentin and S-100. Desmin immunoreactivity was only observed in larger tumors (> 500 microns). Glial fibrillary acid protein was demonstrated nearly exclusively in smaller ones. Immunostaining for neurofilament was restricted to entrapped ganglion cells. Based on conventional light microscopic examination and immunohistochemical evaluation, the lesion was diagnosed as multiple benign peripheral nerve sheath tumors in the small intestine.

Animals↗
PubMed1995

[Intraosseous epidermoid cysts of the toe phalanx in dogs].

Out of 1057 amputated canine toes with tumours, tumour-like or other lesions, 17 cases were histopathologically diagnosed as epidermoid cysts of the terminal phalanx (EP). They were accompanied by osteolysis, reactive bone formation and chronic inflammation of phalanx 3. Extension of reactive changes to the phalangeal joint and phalanx 2 was less frequent. Various breeds were involved. There was no breed predisposition. The average age was 10.8 years; the male-female ratio 2.4:1. Nine EP were located on the forelimbs, 4 on the hindlimbs. In 4 cases location was unknown. Toes 4 and 5 were most frequently affected. A traumatic origin is suspected.

Animals↗