Inhibitory effect of dietary soybean meal on the establishment of a Clostridium strain in the gastrointestinal tract of mice.

The presence of soybean meal in the diet of gnotobiotic mice was shown to prevent the establishment of a clostridial strain in the gastrointestinal tract. Soybean meal did not inhibit the growth of Clostridium in vitro, suggesting that the host plays a role in the observed inhibition of bacterial growth. The inhibitory factor in the soybean meal contains at least two components.     

Hepatitis B virus transmission in Brazilian hemodialysis units: serological and molecular follow-up

A serological and molecular study of hepatitis B virus (HBV) infection was carried out in dialysis units in Central Brazil. Between 1995 and 1999, serum samples from all HBsAg-positive hemodialysis patients (n = 43) were tested for HBeAg/anti-HBe and subtyping by monoclonal ELISA. HBV DNA was detected by PCR and positive samples were genotyped by restriction fragment polymorphism pattern (RFLP) methodology. TheHBsAg prevalence declined in this population during the survey period (12-5.8%). HBeAg and anti-HBe were detected in 23 (53.5%) and 18 (41.9%) sera, respectively. Thirty-six samples could be HBsAg subtyped: 21 were subtype ayw(3), 14 belonged to adw(2) and one was identified as adw(4). HBV DNA was present in 30 serum samples. Of these, 20 (66.7%) were genotype D, 9 (30%) genotype A, and 1 (3.3%) genotype F. In addition, the RFLP pattern could be determined in samples from 18/20 genotype D patients: D3 (10 strains), D7 (7 strains) and D4 (1 strain); from 8/9 genotype A patients: A1 (6 strains) and A3 (2 strains); and from the patient infected with genotype F: F1. Patterns D3 and D7 were associated closely with HBV infection in the two largest hemodialysis units studied. These findings confirm the value of the RFLP method as an effective molecular epidemiological tool for elucidating HBV transmission in hemodialysis units.     

Anti-MOG autoantibodies in Italian multiple sclerosis patients: specificity, sensitivity and clinical association

There is considerable evidence that multiple sclerosis (MS) is an immune-mediated disease characterized by infiltration of inflammatory cells into the CNS and demyelination. Several myelin proteins may be encephalitogenic, including myelin basic protein, proteolipid protein and myelin oligodendrocyte glycoprotein (MOG), the latter being expressed on the external layer of myelin sheaths and hence accessible to antibody attack. We investigated MOG autoreactivity in serum and cerebrospinal fluid (CSF) by ELISA, employing the recombinant extracellular domain of MOG as antigen. We tested serum samples from 262 MS patients (175 relapsing-remitting, 43 primary progressive and 44 secondary progressive), 131 patients with other neurological diseases (OND) and 307 healthy controls. No patients or controls were receiving immunomodulating treatments. We found anti-MOG antibodies in the serum of 13.7% MS patients, mainly in those with secondary progressive MS (25%), in 13.7% of OND patients and in 6.2% of controls. We found a direct correlation (R(2) = 0.6, P = 0.002) between disease severity and anti-MOG titer only in patients with primary and secondary progressive MS. Anti-MOG antibodies were present in the CSF of 11.4% MS patients and 18.9% OND patients. Intrathecal synthesis of anti-MOG antibodies was demonstrated in four (4.5%) of MS patients and no OND patients. Anti-MOG antibodies are not specific for MS; however, they may characterize a subset of MS patients and this may be revealed by serial assays in relation to changing disease phase.     

Frequency of cytokine polymorphisms in populations from western Europe,Africa, Asia,the Middle East and South America

PCR-SSOP identification procedures for IL-2, IL-6, IL-10, TNF-alpha and TNF-beta cytokine polymorphisms have been developed. Application of the procedures to a range of diverse geographically distributed populations has identified ethnic differences within the groups studied. Five populations were investigated, Northern Ireland, South African Zulu, Omani, Singapore Chinese and Mexican Mestizos.     

Proliferation, activity, and osteogenic differentiation of bone marrow stromal cells cultured on calcium titanium phosphate microspheres

In this study, the behavior of bone marrow stromal cells cultured on calcium titanium phosphate (CTP) microspheres was analyzed. Cell adhesion and proliferation were estimated by the neutral red assay and by total DNA quantification. Morphology and deposition of extracellular matrix were assessed by confocal laser scanning microscopy and/or scanning electron microscopy. The expression of the osteoblastic phenotype was evaluated by monitoring alkaline phosphatase activity and osteocalcin secretion. Results revealed that cells were able to attach and spread on the surface of CTP microspheres, and gradually grow into nearly confluent monolayers. Moreover, cells were able to bridge adjacent microspheres forming microsphere-cell clusters. Cells produced an abundant amount of fibrillar extracellular matrix that covered the substrate surface. Alkaline phosphatase activity peaked around days 7-14 and then decreased until day 21. Cells secreted osteocalcin, with higher levels being detected at day 14 than at day 21. Taken together, these results suggest that CTP microspheres are appropriate scaffolds for the growth and differentiation of cells along the osteoblastic lineage.     

U2AF homology motifs: protein recognition in the RRM world

Recent structures of the heterodimeric splicing factor U2 snRNP auxiliary factor (U2AF) have revealed two unexpected examples of RNA recognition motif (RRM)-like domains with specialized features for protein recognition. These unusual RRMs, called U2AF homology motifs (UHMs), represent a novel class of protein recognition motifs. Defining a set of rules to distinguish traditional RRMs from UHMs is key to identifying novel UHM family members. Here we review the critical sequence features necessary to mediate protein-UHM interactions, and perform comprehensive database searches to identify new members of the UHM family. The resulting implications for the functional and evolutionary relationships among candidate UHM family members are discussed.     

Phenotypic abnormalities: terminology and classification

Clinical morphology has proved essential for the successful delineation of hundreds of syndromes and as a powerful instrument for detecting (candidate) genes (Gorlin et al. [2001]; Syndromes of the Head and Neck; Oxford: Oxford University Press. 1 p]. The major approach to reach this has been careful clinical evaluations of patients, focused on congenital anomalies. A similar careful physical examination performed in patients, who have been treated for childhood cancer, may allow detection of concurrent patterns of anomalies and provide clues for causative genes. In the past, several studies were performed describing the prevalence of anomalies in patients with cancer. However, in most studies, it was not possible to indicate the biologic relevance of the recorded anomalies, or to judge their relative importance. Are the detected anomalies common variants, and should they thus be regarded as normal, or are they minor anomalies or true abnormalities, indicating a possible developmental cause? Classification of items in the categories of common variants (disturbances of phenogenesis with a prevalence >4%), minor anomalies (disturbances of phenogenesis with a prevalence 相似文献   

Origin of Fueguian‐Patagonians: An approach to population history and structure using R matrix and matrix permutation methods

A complicated history of isolation between Fueguian and Patagonian groups (originated by the appearance of the Straits of Magellan) as much as differences in population structure and life strategies constitute important factors in the clustering pattern of those groups. The aim of this work was to test several hypotheses about population structure and history of Fueguian‐Patagonians to propose a model that incorporates predictions for future studies. R matrix methods and matrix permutation analyses were performed upon a data matrix of craniofacial measurements of 441 skulls divided into nine samples pertaining to six Patagonian and three Fueguian populations. Association of biological distances with three matrices representing several settlement patterns was tested using matrix permutation tests. Results of R matrix study show that the minimum genetic distance obtained confirms separation between Fueguians and Patagonians. Moreover, an analysis of residual variances from the expected regression line confirms admixture between Andean and Pampean populations and Araucanian groups, consistent with ethnohistorical observations. A model representing a long history of isolation between Fueguian and Patagonians, rather than a model emphasizing differences in life‐strategies, presented the best correlation with the biological distance matrix. Because similar results were already obtained in archaeological, molecular, and morphological studies, a model for the settlement of Tierra del Fuego is proposed. It is summarized by four main hypotheses that can be tested independently by different disciplines in the future. Am. J. Hum. Biol. 14:308–320, 2002. © 2002 Wiley‐Liss, Inc.     

Solitary fibrous tumour of the thyroid: Clinicopathological,immunohistochemical and ultrastructural study of three cases

We describe three cases of solitary fibrous tumour (SFT) arising from thyroid stroma. Grossly, the tumours were clearly delimited but only partly encapsulated. The following histomorphological growth patterns were observed: bundles of cells in storiform configuration; non-structured bundles; prevalence of fibrous matrix; highly cellular, non-structured; prevalence of loose, non-structured extracellular substance; cellular proliferation and vascular spaces in a haemangiopericytic configuration and a lipomatous component. Immunohistochemical investigation demonstrated intense, diffuse vimentin positivity and focal, less intense actin positivity in all three cases. At electron microscopy we observed a primitive cell of mesenchymal type, with cytoplasm poor in organelles and rich in filaments; this cell sometimes presented differentiation characteristics. SFT is at present the most correct term for the lesions presented here despite some morphological characteristics which differ from cases reported in the literature.