Expression of platelet-derived growth factor (PDGF) and its receptor (R) subunits was evaluated in normal human liver and in cirrhotic liver tissue by in situ hybridization and immunohistochemistry. In normal liver, PDGF and PDGF-R subunit expression was limited to a few mesenchymal cells of the portal tract stroma and vessels. In cirrhotic liver, PDGF-A and -B chain mRNA expression was markedly increased and was co-distributed with immunoreactivity for PDGF-AA and -BB in infiltrating inflammatory cells and along vascular structures within fibrous septa. These aspects were paralleled by a marked overexpression of PDGF-R alpha- and beta-subunit mRNAs and of the relative immunoreactivities in a wide range of mesenchymal cells in fibrous septa and in perisinusoidal alpha-smooth-muscle-actin-positive cells. In general expression and distribution of PDGF-R subunits appeared to be related to the activation of different mesenchymal cell types involved in the fibroproliferative process. Therefore, we evaluated the expression of PDGF-R subunits in liver tissue specimens with increasing degrees of necroinflammatory activity. The results of this additional study confirmed that expression of PDGF-R subunits is highly correlated with the severity of histological lesions and collagen deposition. Our results, providing evidence for a functional involvement of PDGF/PDGF-R in liver fibrogenesis, greatly support the results of previous in vitro studies and direct attention toward pharmacological strategies able to affect the series of signaling events arising from the autophosphorylation of PDGF-R subunits. 相似文献
We suitably adapt the design of a tissue-equivalent phantom used for photoacoustic imaging to construct phantoms for optical elastography. The elastography phantom we consider should have optical properties such as scattering coefficient, scattering anisotropy factor, and refractive index; mechanical properties such as storage and loss modulus; and acoustic properties such as ultrasound velocity, attenuation coefficient, and acoustic impedance to match healthy and diseased tissues. The phantom is made of poly (vinyl alcohol) (PVA) and its mechanical, optical, and acoustic properties are tailored by physical cross-linking effected through subjecting a suitable mix of PVA stock and water to a number of freeze-thaw cycles and by varying the degree of hydrolysis in the PVA stock. The optical, mechanical, and acoustic properties of the samples prepared are measured by employing different techniques. The measured variations in the values of optical scattering coefficient, scattering anisotropy factor, and refractive index and storage modulus are found to be comparable to those in normal and diseased breast tissues. The acoustic properties such as sound speed, acoustic attenuation coefficient, and density are found to be close to the average values reported in the literature for normal breast tissue. 相似文献
66 unrelated patients from Southern India with Duchenne Muscular Dystrophy (DMD) were studied for intragenic deletion in 18 exons and Pm region of the DMD gene using multiplex PCR. Of these 41 (62.1%) showed intragenic deletions. 78% of the deletions were located at the distal hotspot region (44-55 exons) and 22% of the deletions were located at the proximal region (exon 2-19). Exon 50 is most frequently deleted. Deletions in isolated cases were significantly more compared to familial cases. The lower incidence reported from South India compared to North India, is suggestive of variations in the Southern and Northern population. 相似文献
Neural tube defects (NTD) are likely to result from an interaction of several genes and environmental factors. Because periconceptional
folate intake reduces the NTD risk in the fetus, and because mothers of children with NTD showed elevated plasma homocysteine
levels, gene polymorphisms of the folate and homocysteine pathway, such as 5,10-methylenetetrahydrofolate reductase (MTHFR) 677C→T, MTHFR 1298A→C and cystathionine β-synthase (CBS) 844ins68, have been implicated in the etiology of NTD. Several studies have demonstrated that these polymorphisms may indeed
be associated with NTD in some populations. In order to evaluate the role of these polymorphisms and their interaction in
NTD, we genotyped 417 individuals for case-control studies and 129 families for transmission disequilibrium tests. We are
the first to present detailed data on MTHFR haploid genotypes in combination with CBS 844ins68. The MTHFR risk genotype 677CT/1298AC, known to be associated with decreased enzyme activity and increased homocysteine, was found significantly
more often in patients than in controls (P = 0.02). A CBS insertion allele in addition to MTHFR 677CT/1298AC heterozygosity or MTHFR 677TT/1298AA homozygosity did not result in an increased risk for NTD. This is in agreement with the recently reported homocysteine-lowering
effect of the CBS 844ins68 allele in carriers of MTHFR variants.
Received: August 28, 2000 / Accepted: December 4, 2000 相似文献
Adenosine Deaminase (ADA) levels were estimated in cord blood of 30 neonates born with birth weight less than or equal to 2.5 kg and 30 neonates born with birth weight greater than 2.5 kg. The mean ADA levels in low birth weight (LBW) group was found to be 6.94 U/L and in normal birth weight group the mean ADA levels were 14.37 U/L which was statistically significant. Therefore ADA may be useful in assessing CMI status in low birth weight infants. 相似文献
Kinetic studies of the polymerization of 1-octene with the Ziegler-Natta catalyst systems VOCl3—AlEt3 (I) and VOCl3—AlEt2Br (II) are reported. The effect of the various parameters such as the Al/V ratio, catalyst and monomer concentrations, reaction time, aging time and temperature on rate of reaction and molecular weight of polymer were studied. Each of these parameters has a profound effect on the polymer yield and the rate of the reaction for both systems. The rate of polymerization increases linearly with increasing temperature, catalyst and monomer concentrations. The reaction is first order with respect to both the monomer and the catalyst concentration in the two catalyst systems studied. From the Arrhenius plot the overall activation energy of polymerization for the two systems was found to be 51,2 and 43,5 kJ/mol, respectively. The mechanism of polymerization is discussed on the basis of the dependence of the polymerization rate on the alkylaluminium concentration. 相似文献
Glioblastoma is associated with a poor prognosis. Even though survival statistics are well-described at the population level, it remains challenging to predict the prognosis of an individual patient despite the increasing number of prognostic models. The aim of this study is to systematically review the literature on prognostic modeling in glioblastoma patients. A systematic literature search was performed to identify all relevant studies that developed a prognostic model for predicting overall survival in glioblastoma patients following the PRISMA guidelines. Participants, type of input, algorithm type, validation, and testing procedures were reviewed per prognostic model. Among 595 citations, 27 studies were included for qualitative review. The included studies developed and evaluated a total of 59 models, of which only seven were externally validated in a different patient cohort. The predictive performance among these studies varied widely according to the AUC (0.58–0.98), accuracy (0.69–0.98), and C-index (0.66–0.70). Three studies deployed their model as an online prediction tool, all of which were based on a statistical algorithm. The increasing performance of survival prediction models will aid personalized clinical decision-making in glioblastoma patients. The scientific realm is gravitating towards the use of machine learning models developed on high-dimensional data, often with promising results. However, none of these models has been implemented into clinical care. To facilitate the clinical implementation of high-performing survival prediction models, future efforts should focus on harmonizing data acquisition methods, improving model interpretability, and externally validating these models in multicentered, prospective fashion.
Anthropometric standards were employed to assess the nutritional status of 452 newborns and 2210 additional children under 5 years of age, from both urban and semi-urban areas of Manipur, India. According to the Indian Standard, 86.3% of these children had normal weight-for-age and 73.8% had weights exceeding 100% of this standard. However, when the US (Harvard) standard was used, 64% were classified as having low weight-for-age and 66% had protein-energy malnutrition. In terms of height, 90% were normal according to the Indian Standard, compared to only 64.7% by the Harvard standard. Mid-upper arm circumference was 90% of the US standard. Chest and head circumference ratios exceeded 1 by the second year of life, while 6 months is the expected time for this development. Malnutrition was more prevalent among girls than boys. Recurrent infections and parasite infestations are presumed to have a cumulative negative effect on child nutritional status in this population. 相似文献