Apolipoprotein E-dependent inverse regulation of vertebral bone and adipose tissue mass in C57Bl/6 mice: modulation by diet-induced obesity.

The long prevailing view that obesity is generally associated with beneficial effects on the skeleton has recently been challenged. Apolipoprotein E (apoE) is known to influence both adipose tissue and bone. The goal of the current study was to examine the impact of apoE on the development of fat mass and bone mass in mice under conditions of diet-induced obesity (DIO). Four week-old male C57BL/6 (WT) and apoE-deficient (apoE(-/-)) mice received a control or a diabetogenic high-fat diet (HFD) for 16 weeks. The control-fed apoE(-/-) animals displayed less total fat mass and higher lumbar trabecular bone volume (BV/TV) than WT controls. When stressed with HFD to induce obesity, apoE(-/-) mice had a lower body weight, lower serum glucose, insulin and leptin levels and accumulated less white adipose tissue mass at all sites including bone marrow. While WT animals showed no significant change in BV/TV and bone formation rate (BFR), apoE deficiency led to a decrease of BV/TV and BFR when stressed with HFD. Bone resorption parameters were not affected by HFD in either genotype. Taken together, under normal dietary conditions, apoE-deficient mice acquire less fat mass and more bone mass than WT littermates. When stressed with HFD to develop DIO, the difference of total body fat mass becomes larger and the difference of bone mass smaller between the genotypes. We conclude that apoE is involved in an inverse regulation of bone mass and fat mass in growing mice and that this effect is modulated by diet-induced obesity.

Clinical and immunohistologic typing of salivary duct carcinoma: a report of 50 cases.

BACKGROUND: Due to the low incidence of salivary duct carcinoma (SDC), only limited data in regard to the biologic behavior of this tumor and its immunohistochemical characteristics are available. The authors analyzed the clinical, molecular, and genetic profile of SDC and identified prognostic factors. METHODS: The follow-up of 50 patients with SDC was obtained and paraffin-embedded tumor samples were examined immunohistochemically. In all samples, the expression of Ki-67, HER-2, and the oncoproteins p16 and p53 was examined immunohistochemically, followed by a mutation analysis of p16 and p53. The survival rate was calculated by the Kaplan-Meier method and prognostic variables were analyzed with the log-rank test. RESULTS: SDC predominantly effected male patients (66%) in their 7th decade of life. SDC mainly occurred in the parotid gland (78%; submandibular gland, 12%; minor salivary glands, 10%). Approximately two-thirds of the patients (33 of 50) presented with a T3/T4 tumor. In 28 patients (56%), cervical lymph node metastasis was present at the time of diagnosis. Local disease recurrence was observed in 48% of patients an average of 17.4 months after initial treatment. Distant disease metastasis developed in 48% of patients an average of 29 months after initial treatment. The average overall survival period was 56.2 months. In the current study, 20.6% of the probes with positive HER-2/neu expression were (+++) positive. p53 was expressed in 83.9% of the tumor samples. In 11.8% of the tumor samples, there was a lack of p16 expression. CONCLUSIONS: Mutations of the p53 gene were more frequent in tumor samples with (++) and (+++) immunoreactivity and mainly affected exons 7 and 8. A mutation of the p16 gene was only found in 1 tumor sample. Expression of HER-2/neu and p53 was statistically linked (P < 0.05) to early local disease recurrence, distant disease metastasis, and survival rates.

Immunohistochemical long-term evaluation of laminin expression in microvascular anastomoses of the carotid artery in the Wistar rat.

INTRODUCTION: The main risk of complications of free-flap tissue transfer is from the microvascular anastomoses. The anastomoses are threatened by thrombosis, aneurysm and vascular insufficiency. Laminin is associated with the basement membrane complex and plays an essential role in vascular tissue organization, wound healing and supports mechanical properties of vessels. A long-term animal experiment was used to obtain new information on the distribution of laminin in anastomoses. METHODS: Seventy Wistar rats, seven groups of 10 animals each, were operated upon. A 4mm long segment of common carotid artery was removed and reinserted. After various periods (from directly postoperative to 6 months later), the common carotid arteries, including the bifurcation, were isolated after cardiovascular perfusion. Carotid arteries were embedded and cross-sections stained using an immunohistochemical anti-laminin-antibody. Two anastomoses with four sutures each were examined by using this technique to evaluate histomorphology and intensity of anti-laminin staining. RESULTS: Compression, shift and dehiscence were often seen following vessel apposition. A loss of laminin expression was observed in the media in cases of compression and shift after 6 months. The grade of expression of laminin in anastomoses was dependent on the extent of injury. CONCLUSIONS: The application of antibodies to identify the laminin distribution was valuable for studying vascular healing. A well-performed microvascular anastomosis is clinically important not only for the acute phase following the operation, but also long term. Further antibody studies could be used in follow-up studies of vascular prostheses.

Oral Langerhans cell histiocytosis: antigen-Ki-67 as a indicator for local tumor behaviour.

AIM: Our aim was to compare the different methods of treatment available for Langerhans cell histiocytosis (LCH) in the oral maxillofacial region. A classification based on clinical and immunohistochemical data is proposed and a grading for disease severity is provided. PATIENTS AND METHODS: The records and clinical data of 12 patients were evaluated retrospectively. The patients ages ranged from 20 months to 47 years. Nine had manifestations in the maxillo-facial region, of which six had a single oral manifestation only, with the three remaining ones having multiple manifestations in this region. Three patients had additional manifestations in the upper thorax (coming to a total of twelve patients). Eleven patients were surgically treated with one having been treated previously with a steroid-therapy. One patient had been treated with chemotherapy. The longest duration of follow-up was 16 years. Immunohistochemical stains for antigen-CD1a, antigen-S-100 and antigen-Ki-67 were performed. A proposal for staging the manifestations in the oromaxillo-facial-region was made. The intensity of the antigen-Ki-67 stains were evaluated. RESULTS: One patient presented a relapse only implying that surgical treatment was very effective in the eradication and cure of the disorder. Eleven patients exhibited no signs of recurrence. It is felt that the number of antigen-Ki-67-positive cells is related to the activity of the disease. CONCLUSION: Langerhans cell histiocytosis should be treated surgically. Only in very severe cases should surgical treatment be complimented by either radiotherapy or chemotherapy. Especially in disseminated cases, chemotherapy seems to improve the outcome. Antigen-Ki-67 as a proliferation marker is suggested as a grading parameter for local tumor behaviour.

Relative paucity of gross genetic alterations in myoepitheliomas and myoepithelial carcinomas of salivary glands.

The diagnosis of salivary gland myoepithelioma, an entity with heterogeneous cytomorphology and inconsistent immunophenotype, rests on conventional histology. However, the clinical course cannot be predicted reliably from cytomorphological and immunophenotypic analysis. The present study determined the immunophenotype of a representative series of 12 myoepitheliomas and 21 malignant myoepitheliomas. Among the seven markers tested, antibodies against cytokeratins 5/6, S-100 protein, and vimentin produced the most consistent reactivity profile. Comparative genomic hybridization (CGH) profiles of 12 myoepitheliomas showed chromosomal losses in three of 12 cases. In myoepithelial carcinomas, however, ten of 19 tissues investigated by CGH lacked detectable cytogenetic aberrations. In five cases, aberrations involved chromosome 8, in line with observations in salivary gland carcinomas of other differentiation. One case that was represented in three separately localized manifestations of the disease proved informative as to the relevance of gross aberration for tumour development, as these tumours differed in their CGH profiles. Staining for cytokeratins 5/6 is a useful addition to the established immunohistological marker panel in the work-up of myoepitheliomas, because of its reliable expression in most cases and because it may underline the epithelial nature of the lesion. CGH proved to be of limited value as a diagnostic adjunct; the presence of numerous gross cytogenetic aberrations should raise the suspicion of malignancy. The low frequency of aberrations detectable by CGH in overtly malignant myoepithelial neoplasms suggests that gross cytogenetic alterations were acquired in the course of tumour progression and points to the relevance of genetic changes not resolved by CGH.

Oral Langerhans cell histiocytosis.

AIM: Our aim is to compare the different methods of treatment available for Langerhans cell histiocytosis (LCH) in the oral and maxillo-facial region. A classification based on clinical and immunohistochemical data is proposed and a grading for the severity of the disease is proposed. PATIENTS AND METHODS: Records and clinical data of 12 patients were evaluated retrospectively. The patients' ages ranged from 20 months to 47 years. Nine had manifestations in the maxillo-facial region, of which six had a single oral lesion only, with the three remaining patients having multiple lesions in this region. Three patients had lesions in the upper thorax in addition to their oral lesions. Eleven patients were treated surgically with one having been treated previously with steroid-therapy. One patient had already been treated with chemotherapy. The longest follow-up was 16 years. Immunohistochemical stains for antigen-CD-1a, antigen-S-100 and antigen-Ki-67 were performed. A proposal for staging the lesions in the oro-maxillo-facial region was made. The intensity of the antigen-Ki-67 stains was evaluated. RESULTS: Eleven patients exhibited no signs of recurrence whilst only one patient had a recurrence implying that surgical treatment was very effective in eradication and cure of the disorder. It is felt that the number of antigen-Ki-67 positive cells is related to the activity of the disease. CONCLUSION: Langerhans cell histiocytosis should be treated surgically. Only in very severe cases should surgical treatment be complemented with either radio-therapy or chemotherapy. Especially in disseminated cases, chemotherapy would appear to improve the outcome. The antigen Ki-67 as proliferation marker is suggested as a grading parameter of this disease.