Hepatitis C virus antibodies in chronic liver diseases of different aetiology.

To define the prevalence of Hepatitis C Virus (HCV) infection in patients with chronic hepatitis or cirrhosis of any aetiology, we tested a group of 372 consecutive subjects with biopsy-proven chronic liver disease (CLD) for anti-HCV antibodies, excluding active drug-addicts and alcoholics. Our results show that in Southern Italy HCV infection is widespread among subjects with cryptogenic chronic liver disease, as well as in liver diseases with features of autoimmunity (71.7% and 66.7% anti-HCV positive, respectively). Anti-HCV is infrequent among non drug-addicted HBsAg positive subjects (4.7%), and bears no relation to hepatitis D superinfection. Subjects with CLD and a history of parenteral exposure are almost always anti-HCV positive (89.2%). Patients with HBV-related CLD and previous drug-addicts are on the average younger than other disease groups, irrespective of their HCV status. Among subjects whose CLD is related to parenteral exposure, cryptogenic or autoimmune no increase in the rate of anti-HCV positivity seems to bear a parallel relationship to age. No known risk factor for parenteral transmission, other than use of blood or blood products and previous drug-addiction, can be clearly related to HCV infection. No trend to familiar clustering of HCV-induced liver disease is apparent. Liver disease severity, as assessed by transaminase levels and liver histology, does not correlate to anti-HCV status.     

MRI and PET of delayed heavy-ion radiation injury in the rabbit brain

Magnetic resonance imaging (MRI) and positron emission tomography (PET) techniques were used to obtain in vivo scans of delayed (30 GyE helium ion, 230 MeV/u) radiation injury in rabbit brain. T2-weighted (T2W) MRI scans demonstrated alterations that were restricted primarily to the white matter tracts and the deep perithalamic and thalamic regions. Quantitative measurements of T2 and T1 values demonstrated wide variations in absolute values. However, paired comparisons in hemibrain-irradiated rabbits revealed significant increases in T2 (p less than 0.001) and T1 (p less than 0.01) in irradiated versus unirradiated brain. Gadolinium DTPA (GdDTPA) enhanced MRI and 82Rubidium (82Rb) PET detected focal regions of blood-brain barrier (BBB) disruption restricted to the deep white matter and thalamic regions. Sequential GdDTPA enhanced MRI scans showed the spreading of the tracer from the initial site of contrast enhancement. 18Fluorodeoxyglucose (18FDG) PET studies demonstrated the markedly depressed metabolic profiles of irradiated brain. Histological findings of tissue edema and necrosis correlated well with the in vivo imaging abnormalities. These initial studies demonstrate that the irradiated rabbit brain is a suitable animal model for examining the delayed effects of radiation injury in the brain.     

An experimental compartmental flow model for assessing the hemodynamic response of intracranial arteriovenous malformations to stereotactic radiosurgery

Stereotactic radiosurgery has proven to be an effective method of treating selected inaccessible or inoperable arteriovenous malformations (AVMs) of the brain. Radiation-induced obliteration of successfully-treated AVMs, however, occurs only after some latent period after treatment, depending on size, location, and dose. An experimental compartmental flow model is proposed to describe the hemodynamic alterations in the AVM as a result of the pathophysiological changes after radiosurgery, and to analyze temporal alterations in AVM blood flow rates and pressure gradients before complete obliteration. In representative small (low-flow, 150 ml/min) and large (high-flow, 440 ml/min) AVMs, it is found that increases in pressure gradients across certain vascular structures within the AVM occur during the normal course of radiation-induced flow decrease and AVM obliteration. The magnitude of these pressure alterations, however, may be within the normal physiological variations in cerebrovascular blood pressure. The effects of partial-volume irradiation of the AVM is examined by limiting radiosurgical treatment to varying portions of the flow compartments within the model. It is found that alterations in pressure gradients persist in unirradiated vascular shunts, even after complete obliteration of the treated AVM volume. These pressure alterations may increase the probability of hemorrhage from the untreated shunts of the AVM and cause redistribution of regional cerebral blood flow resulting in increased flow through these untreated shunts.     

Noninvasive prenatal diagnosis of monogenic diseases by digital size selection and relative mutation dosage on DNA in maternal plasma

Prenatal diagnosis of monogenic diseases, such as cystic fibrosis and β-thalassemia, is currently offered as part of public health programs. However, current methods based on chorionic villus sampling and amniocentesis for obtaining fetal genetic material pose a risk to the fetus. Since the discovery of cell-free fetal DNA in maternal plasma, the noninvasive prenatal assessment of paternally inherited traits or mutations has been achieved. Due to the presence of background maternal DNA, which interferes with the analysis of fetal DNA in maternal plasma, noninvasive prenatal diagnosis of maternally inherited mutations has not been possible. Here we describe a digital relative mutation dosage (RMD) approach that determines if the dosages of the mutant and wild-type alleles of a disease-causing gene are balanced or unbalanced in maternal plasma. When applied to the testing of women heterozygous for the CD41/42 (–CTTT) and hemoglobin E mutations on HBB, digital RMD allows the fetal genotype to be deduced. The diagnostic performance of digital RMD is dependent on interplay between the fractional fetal DNA concentration and number of DNA molecules in maternal plasma. To achieve fetal genotype diagnosis at lower volumes of maternal plasma, fetal DNA enrichment is desired. We thus developed a digital nucleic acid size selection (NASS) strategy that effectively enriches the fetal DNA without additional plasma sampling or experimental time. We show that digital NASS can work in concert with digital RMD to increase the proportion of cases with classifiable fetal genotypes and to bring noninvasive prenatal diagnosis of monogenic diseases closer to reality.     

The Impact of the Acculturation Process on Asian American Youth's Psychological Well-Being

TOPIC: Acculturation process and Asian American youth's psychological well-being. PURPOSE: This paper provides an overview of acculturation, its correlates, and psychological well-being of Asian American youth. SOURCES USED: Interdisciplinary research related to acculturation, ethnic socialization, and minority youth's psychological outcomes. CONCLUSIONS: Familial ethnic socialization is mediated by demographic variables, parents' attitudes, and parent–child relationships. Parent–child relationships during acculturation predicts Asian American youth's psychological outcomes. The key components of culturally sensitive health care for Asian American youth include evaluation of family relationships, congruence in parents' and youth's acculturation patterns, and sensitivity to implications of the model minority image.     

Relaxation-compensated fast multislice amide proton transfer (APT) imaging of acute ischemic stroke.

Amide proton transfer (APT) imaging is a variant form of chemical exchange saturation transfer (CEST) imaging that is based on the magnetization exchange between bulk water and labile endogenous amide protons. Given that chemical exchange is pH-dependent, APT imaging has been shown capable of imaging ischemic tissue acidosis, and as such, may serve as a surrogate metabolic imaging marker complementary to perfusion and diffusion MRI. In order for APT imaging to properly diagnose heterogeneous pathologies such as stroke and cancer, fast volumetric APT imaging has to be developed. In this study the evolution of CEST contrast after RF irradiation was solved showing that although the CEST steady state is reached by the apparent longitudinal relaxation rate, the decreases of CEST contrast after irradiation is governed by the intrinsic relaxation constant. A volumetric APT imaging sequence is proposed that acquires multislice images immediately after a single long continuous wave (CW) RF irradiation, wherein the relaxation-induced loss of CEST contrast is compensated for during postprocessing. The proposed technique was verified by numerical simulation, a tissue-like dual-pH phantom, and demonstrated on an embolic stroke animal model. In summary, our study has established a fast volumetric pH-weighted APT imaging technique, allowing further investigation to fully evaluate its diagnostic power.     

Relationship between grip strength and bone mineral density in healthy Hong Kong adolescents

Summary  This study evaluated the magnitude of the correlations among grip strength, bone mineral density (BMD) and bone mineral content (BMC), after controlling for weight, height, pubertal development, weight-bearing activities and calcium intake. The results lead to the conclusion that grip strength is an independent predictor of bone mass in both sexes. The relationship between muscle strength and bone mass is systemic. Introduction  Previous studies had shown a site-specific relationship between muscle strength and bone in pubertal children. This study evaluated the magnitude of the correlations among grip strength, bone mineral density (BMD) and bone mineral content (BMC) at distant bone. Methods  Cross-sectional data of 169 11- to 12-year-old boys and 173 10- to 11-year-old girls came from the baseline result of a cohort study. Grip strength, BMD, BMC, weight, height, pubertal development, weight-bearing activities and calcium intake were measured. Pearson correlations and multiple regressions were used to calculate univariate and adjusted associations among grip strength and bone mass at distant bone. Results  Significant correlations were shown between grip strength and bone mass at hip, spine and whole body (boys: BMC:0.72–0.74, BMD:0.38–0.60; girls: BMC:0.71–0.72, BMD:0.44–0.63; p<0.0001). Multiple regressions with all covariates showed that about 70% and 50%, respectively, of the variations in BMC and BMD could be explained but not for whole body BMD. Grip strength was an independent predictor of bone mass, except hip BMD in boys and whole body BMD in girls. Stepwise regression showed that grip strength was a robust predictor in both sexes. Prediction models by grip strength and weight explained about 60% and 40% of the variations in BMC of different sites and in BMD of hip and spine, respectively. Conclusions  We found that grip strength is an independent predictor of bone mass in both sexes. The relationship between muscle strength and bone mass is systemic.