Rat interscapular brown adipose tissue at different ages: a morphometric study

Interscapular brown adipose tissue (IBAT) was studied in newborn and 1, 3, 5, 7, 13, 26, 52, 78 and 104-week-old rats maintained under standard laboratory conditions in order to define its morphological modifications and assess previous statements on an involution phase of IBAT after the first weeks of extrauterine life. Serial sections were analysed morphometrically to quantify the multilocular, the monolocular and the connective-vascular components of IBAT. Morphometry shows that the IBAT weight and volume progressively increase up to the twenty-sixth week of age, these figures remaining almost constant thereafter. The volume of the unilocular and connective components increased with age. The volume of the multilocular component increases up to the sixth month of age, and slightly reduces thereafter. The number of the multilocular adipocytes is almost constant from the third week up to the second year of life. Our results suggest that, in IBAT of adult animals, despite a slight prevalence of unilocular adipocytes, the number of multilocular cells is not reduced with respect to younger animals.     

Primary alveolar soft part sarcoma of the stomach: a case report and review

Alveolar soft part sarcoma (ASPS) is a rare tumor typically located in skeletal muscles and muscolofascial planes. Isolated cases of ASPS have been described as arising in the viscera. We report a mesenchymal tumor of the stomach in a 54-year-old Italian woman without evidence of primary neoplasm elsewhere ten years following the initial diagnosis. The histologic, histochemical, immunohistochemical, and electron microscopic findings were all consistent with the diagnosis of ASPS and allowed differentiating it from morphologically similar and more common tumors, such as metastatic renal cell carcinoma and paraganglioma. The patient is alive and well ten years following the initial presentation.     

S-100 protein in white preadipocytes: An lmmunoelectronmicroscopic study

Differentiation of adipocytes from their precursor cells (preadipocytes) is an important problem in the study of the pathogenesis of obesity. Unfortunately, among the immature stages of adipocytes, only relatively differentiated forms can be identified by their fine structure; because early preadipocytes cannot be distinguished from fibroblasts solely on the basis of their morphology, it is impossible to assess the size of the preadipocyte population. S-100 protein has been identified in various mammalian tissues and recently mature adipocytes have been shown to be positive for this protein. Because fibroblasts are negative for S-100 protein, the present study tested the S-100 immunoreactivity of preadipocytes by the peroxidase-antiperoxidase (PAP) preembedding method at the ultrastructural level both in vivo and in culture. Mature adipocytes and early preadipocytes, including fibroblast-like cells devoid of lipid droplets, were positive both in vivo and in culture. Endothelial cells and pericytes were negative; but flattened, lipid-free, fibroblast-like cells surrounding the pericytes were positive. True fibroblasts both in vivo and in culture were negative. Therefore, S-100 protein can be a useful biochemical marker in distinguishing fibroblasts from early preadipocytes.     

Multiple symmetric lipomatosis. Ultrastructural investigation of the tissue and preadipocytes in primary culture

Multiple symmetric lipomatosis (MSL) is characterized by enlarging, painless fat deposits in the neck and upper trunk. The pathogenesis of MSL is unknown. Owing to localization of MSL fat deposits in the neck and interscapular region, it has been suggested that they could originate from brown fat. However, the histological appearance of MSL adipose tissue is that of white fat, with prevailing monovacuolar adipocytes. Nevertheless, MSL adipocytes are smaller than adipocytes of the common white adipose tissue and show peculiar metabolic features. The ultrastructure of MSL lesions has been not described. The present work investigated the ultrastructural morphology of MSL adipose tissue and lipomatous adipocyte precursors maintained in long-term culture. Samples of lipomatous tissue were obtained from patients affected with MSL undergoing surgical lipectomy. Portion of the tissue was processed for electron microscopy; the rest was digested with collagenase, and isolated preadipocytes from the stromal-vascular fraction were cultured up to 15 days. Cultured cells were prepared for electron microscopy in situ and their morphology compared with human white adipose tissue preadipocytes and rat brown preadipocytes cultured in parallel. Results show the following. 1) Adipocytes of MSL are not monovacuolar and resemble the largest adipocytes that can be found in rat and human brown fat. 2) Some morphological features of MSL adipocyte precursors resemble brown adipocyte more than white: cultured MSL preadipocytes transiently develop large mitochondria with parallel cristae resembling those of the brown fat cell and maintain a multivacuolar lipid deposit in culture, i.e. a typical feature of brown preadipocytes. 3) Some morphological features suggest a neoplastic nature of MSL adipocytes. Taken together, these findings suggest that MSL is a neoplastic disease which could originate in brown fat.     

Pachydermoperiostosis (primary hypertrophic osteoarthropathy): report of a case with evidence of endothelial and connective tissue involvement.

A case of pachydermoperiostosis characterised by the presence of finger clubbing, periostosis, sweating of hands and feet is described. Modifications of capillaroscopic pattern and of arteriovenous anastomoses are reported. The periungual border and finger tip tissue showed diffuse endothelial hyperplasia, hyalinosis, and sclerosis with packing of collagen fibres. Electron microscopy showed hypertrophic and activated endothelia (numerous and hypertrophic Golgi complexes, several Weibel-Palade bodies, vesicles of micropinocytosis, and glycogen particles), the basal membrane thickened and reduplicated, perivasal infiltrate in superficial derma, reticulation and segmentary reduplication of basal membrane in arteriovenous shunt. In the perineural connective tissue numerous Luse bodies (long spacing collagen) were evident. The data indicate that in the early phase of pachydermoperiostosis morphological endothelial and collagen fibre abnormalities are present, though there is a normal peripheral blood flow.     

“CADASIL coma” in an Italian homozygous CADASIL patient: comparison with clinical and MRI findings in age-matched heterozygous patients with the same G528C NOTCH3 mutation

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic disorder caused by mutations in the NOTCH3 gene, with a striking variability in phenotypic expression. To date, only two homozygous patients have been reported, with divergent phenotypic features. We describe an Italian CADASIL patient, homozygous for G528C mutation, in whom early manifestation of the disease was migraine, but whose clinical evolution was characterized by a reversible acute encephalopathy followed by full recovery (“CADASIL coma”). Clinical evaluation, MR scan, neuropsychological and neurophysiological investigation did not reveal substantial differences between our homozygous patient and her heterozygous relatives sharing the same mutation, or between our patient and a group of heterozygous individuals with the same mutation but from different families. Skin biopsy identified peculiar features in the homozygous patient, with cytoplasmic pseudoinclusions likely containing granular osmiophilic material (GOM) in the vascular smooth muscle cells, but further studies are necessary to substantiate their possible relationships with CADASIL homozygosis. “CADASIL coma” did not seem to be specific of patient’s homozygosis, since it was observed in one of her heterozygous relatives, whereas its pathogenesis seems to be related to peculiar constellations of unknown predisposing factors. The present study demonstrated that CADASIL conforms to the classical definition of dominant diseases, according to which homozygotes and heterozygotes for a defect are phenotypically indistinguishable.     

A New Anorganic Equine Bone Substitute for Oral Surgery: Structural Characterization and Regenerative Potential

Different xenogeneic inorganic bone substitutes are currently used as bone grafting materials in oral and maxillo-facial surgery. The aim of the present study was to determine the physicochemical properties and the in vivo performance of an anorganic equine bone (AEB) substitute. AEB is manufactured by applying a process involving heating at >300 °C with the aim of removing all the antigens and the organic components. AEB was structurally characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier-transformed infrared (FT-IR) spectroscopy and compared to the anorganic bovine bone (ABB). In order to provide a preliminary evaluation of the in vivo performance of AEB, 18 bone defects were prepared and grafted with AEB (nine sites), or ABB (nine sites) used as a control, in nine Yucatan Minipigs. De novo bone formation, residual bone substitute, as well as local inflammatory and tissue effects were histologically evaluated at 30 and 90 days after implantation. The structural characterization showed that the surface morphology, particle size, chemical composition, and crystalline structure of AEB were similar to cancellous human bone. The histological examination of AEB showed a comparable pattern of newly formed bone and residual biomaterial to that of ABB. Overall, the structural data and pre-clinical evidence reported in the present study suggests that AEB can be effectively used as bone grafting material in oral surgery procedures.