The pathogenesis of molybdenum cofactor deficiency, its delay by maternal clearance, and its expression pattern in microarray analysis

Molybdenum cofactor (Moco)-deficiency is a lethal autosomal recessive disease, for which until now no effective therapy is available. The biochemical hallmark of this disorder is the inactivity of the Moco-dependent sulfite oxidase, which results in elevated sulfite and diminished sulfate levels throughout the organism. In humans, Moco-deficiency results in neurological damage, which is apparent in untreatable seizures and various brain dysmorphisms. We have recently described a murine model for Moco-deficiency, which reflects all enzyme and metabolite changes observed in the patients, and an efficient therapy using a biosynthetic precursor of Moco has been established in this animal model. We now analyzed these mice in detail and excluded morphological brain damage, while expression analysis with microarrays indicates a massive cell death program. This neuronal damage appears to be triggered by elevated sulfite levels and is ameliorated in affected embryos by maternal clearance.     

A fatal case of necrotizing sinusitis due to toxigenic Corynebacterium ulcerans

A 77-year-old farmer developed cough with sputum production, fever, bloody nasal discharge and a mass in his right maxillary sinus leading to necrotic ulceration of the sinus. Corynebacterium ulcerans, carrying the beta-phage for the diphtheria toxin and secreting the toxin, was detected microscopically and by culture from the sinusoidal and ulcer discharge. Despite immediate antimicrobial chemotherapy the patient died of pulmonary failure associated with the production of large amounts of very viscous sputum. Identification of the causative agent, pathophysiological aspects and risk factors of this unusal infection are discussed.     

Melanotic ectodermal tumor of infancy (melanotic progonoma)--an unusual soft tissue tumor

In rare cases an utmost uncommonly pigmented lesion is found in young infants which is mostly located in the anterior maxilla. The histogenesis of this unusual soft tissue tumor has provoked a long-lasting debate, which is reflected in many synonyms. There is no anatomical precursor and the possibility of a phylogenetic ancestral form is discussed. Therefore, the term melanotic progonoma was proposed. Because of the derivation from neural crest cells the designation melanotic neuroectodermal tumor of infancy was introduced. This name is now generally accepted. In this study, two typical cases of this rare tumor are described. The tumors are composed of large epithelial-like melanin-producing cells and small nonpigmented cells, so-called lymphocyte- like cells resembling neuroblasts. The diagnostic relevant histological pattern is characterized by intensely pigmented cells arranged either in strands or clusters often forming the lining of small cleft-like or tubular spaces, or by alveolar structures surrounded by a fibrovascular stromal component. At ultrastructural level, the pigment corresponds to the cutaneous type of neural crest type of melanin. The histogenesis of these lesions and the classification of pigmented benign and malignant neuroectodermal tumors of the soft tissues are discussed especially taking into consideration the concept of the soft tissue variant of melanomas. The melanotic neuroectodermal tumor of infancy is a benign growth Only in very few cases a fatal outcome is reported in the literature. The melanotic neuroectodermal tumor of infancy must be distinguished from other types of benign and malignant neuroectodermal tumors. From histological point of view and with regard to its biological behaviour this lesion is a particular entity of pigmented neuroectodermal tumors of the soft tissues, and for subclassification the term melanotic progonoma should be maintained, too.     

Unrelated donors selected prospectively by block-matching have superior bone marrow transplant outcome

Previous retrospective studies have demonstrated improved outcome in patients whose donors were matched for non-HLA markers in the MHC as well as for HLA genes. Forty patients receiving transplants from unrelated donors were typed prospectively for HLA and non-HLA markers. Non-HLA markers near HLA-B (beta-block markers) and in the DRB1 introns (delta-block markers) were used to assess MHC match between donors and recipient. Patients whose donors were matched at the beta- and delta-blocks had improved event free survival (63%) compared to patients whose donors were mismatched at one or both blocks (25%) (p < 0.05). Patients whose donors were matched at the beta-block had significantly less severe acute graft versus host disease (p < 0.05). In order to investigate the basis for improved outcome block matching was correlated with HLA matching as determined by DNA sequencing. Beta-block matching was highly correlated with matching for exons 2 and 3 of HLA-B but less so for HLA-C. Delta-block matching was highly correlated with matching for exon 2 of HLA DRB1. It is concluded that matching for non-HLA markers in the MHC improves matching for HLA genes. Further studies are required to determine whether matching for non-HLA markers improves outcome to a greater extent than matching for the HLA genes alone.     

Three-dimensional in vitro model of adipogenesis: comparison of culture conditions

In vivo and in vitro studies have demonstrated both promise and current limitations in tissue engineering of fat. Herein, we report the establishment of a well-defined three-dimensional (3-D) in vitro model useful for systematic investigations of 3-D adipogenesis. Polyglycolic acid fiber meshes were dynamically seeded with 3T3-L1 preadipocytes; subsequently, cell-polymer constructs were hormonally induced and cultivation under three different conditions was evaluated. Regarding tissue coherence and intracellular lipid content, culture of cell-polymer constructs either dynamically in well plates or in stirred bioreactors yielded similar results, which were distinctly improved compared with static conditions in well plates. At the protein and mRNA levels, significantly increased expression of genes characteristic for a mature adipose phenotype was demonstrated for constructs dynamically cultured in well plates, as compared with static conditions. Furthermore, investigation of lipolysis under stimulating and inhibiting conditions demonstrated functionality of the dynamically differentiated constructs. Using dynamic culture conditions, the presented in vitro model system is suggested as a valuable tool serving both fat tissue engineering and basic research by facilitating investigations of tissue-inherent features not possible under conventional 2-D culture conditions.     

Ontogeny, differentiation and growth of the endocrine pancreas

The pancreas develops from the primitive foregut endoderm, which differentiates into ductal, acinar and endocrine cells. This complex process is probably replicated in the adult pancreas when endocrine cell renewal is required, as may be the case in diabetes mellitus. This review describes what is known about the morphogenesis of the endocrine pancreas during ontogeny and the mechanisms regulating its differentiation and growth. Received: 23 December 1999 / Accepted: 15 February 2000     

In vivo labeling with1251-CRH of human ACTH-producing pituitary adenomas heterotransplanted to nude mice

Tissue from 23 pituitary adenomas causing Cushing’s disease was implanted subcutaneously into 159 NuNu/NMRi mice, resected after 21 or 35 days, and evaluated histologically and immunohistochemically. After 21 days, 74.3% of the grafts survived, 59% having less than 30% necrotic adenoma cells. After 35 days, 45% of the adenoma fragments survived, 37% having less than 30% necrotic adenoma cells. The preservation of the grafts was essentially dependent on the grade of vascularization accomplished by migration of the host’s capillaries. As assessed by adrenal weight and histologically, biological activity of the transplants could not be detected. Histologically, the grafts maintained the features of their primary tumors, and adrenocorticotropic hormone (ACTH) could be visualized immunohistologically.Seventeen mice with subsequently proved preserved adenoma tissue received an intravenous injection of 12.5 μCi¹²⁵l-corticotropin-releasing hormone (CRH) and light microscopy-autoradiography was performed. Specific labeling, as verified by positive and negative controls, was exhibited by 1 1 of 15 transplants originating from 3 highly differentiated ACTH cell adenomas. Four did not label clearly positive. Two grafts of an undifferentiated mucoid cell pituitary adenoma did not show any labeling.The nude mouse model is a useful tool for the study of ACTH-producing pituitary adenomas in vivo. Highly differentiated ACTH cell adenomas can be labeled with radioactive CRH in vivo.