Evidence for intact semantic representations in patients with frontal lobe lesions

Patients with frontal lobe lesions and control participants were assessed on 2 tests of semantic knowledge. In the triadic comparison task, participants were shown all possible triplets of 12 animal names and judged which 2 of each triplet were most alike. In the ordered similarity task, participants rank ordered animals in terms of their similarity to a target animal. For both tasks, semantic structure--derived from multidimensional scaling techniques--revealed similar representations in patients with frontal lobe lesions and control participants. Additional pathfinder analyses also produced networks that did not differ between groups. These patients exhibited intact semantic knowledge despite deficits on tests of free recall and verbal fluency that involved the same semantic category and exemplars. Thus, intact representation of semantic knowledge in frontal patients stands in contrast to their marked deficits in strategic retrieval of semantic knowledge.     

Myosin VIIA gene: heterogeneity of the mutations responsible for Usher syndrome type IB

Usher syndrome is recognized as the most frequent cause of hereditary deaf-blindness. Usher syndrome type I (USH1), the most severe form of the disease, is characterized by profound congenital sensorineural deafness, constant vestibular dysfunction, and retinitis pigmentosa of prepubertal onset. This form is genetically heterogeneous and five loci (USH1A-E) have been mapped thusfar. However, only the gene responsible for USH1 B (which accounts for approximately 75% of USH1 cases) has been characterized. It encodes a long-tailed unconventional myosin, myosin VIIA, with a predicted 2215 amino acid sequence. Primers covering the complete myosin VIIA coding sequence as well as the 3' non coding sequence were designed, allowing direct sequence analysis of each of the 48 coding exons and flanking splice sites in seven patients affected by USH1. Four novel mutations were thereby identified. The possibility should now be considered of a sequence-based prenatal diagnosis in some of the families affected by this very severe form of Usher syndrome.      

Evaluation of FDA licensed HIV assays using plasma from Cameroonian blood donors

Several diagnostic assays for the detection of HIV infection have been approved and licensed by the FDA for blood donor screening. However, the performance of these assays is unknown when testing genetically divergent blood specimens. To evaluate the performance of these assays with diverse HIV strains, we chose to study specimens collected from blood donors in Cameroon where genetic diversity and recombinant variants are prevalent. In this study, we tested 240 human plasma specimens collected from two blood centers in Cameroon. These samples were screened initially in Cameroon for antibody to HIV using a rapid assay. We also performed sequencing to determine subtype. Our evaluation has demonstrated that HIV infection in most HIV plasma samples could be detected by most of the US FDA licensed diagnostic assays. With the exception of a few specimens, HIV-1 p24 antigen was not detected in any of the samples. In addition, some nucleic acid tests (NAT) assays were not able to detect a few serologic reactive samples and all new variants including some CRF02_AG variants.     

Detection of Human T-Lymphotropic Virus (HTLV) tax Sequences in New York City Blood Donors Seronegative for HTLV Types 1 and 2

A potential public health concern is the reported detection of the human T-lymphotropic virus (HTLV) tax gene in the lymphocytes of up to 11% of a low-risk group of New York City blood donors (NYBD). This study aimed to independently confirm the prevalence of HTLV tax sequences in 293 NYBD. All NYBD tested negative for antibodies to HTLV types 1 and 2 and HTLV Tax. HTLV tax sequences were not detected in the NYBD lymphocytes. These data demonstrate the lack of HTLV-1 tax in this group of NYBD at low risk for HTLV infection.     

Illicit drug use,cigarette smoking and alcohol drinking behaviour among a sample of high school adolescents in the Pietersburg area of the Northern Province,South Africa

AIM: The aim of this study was to investigate the prevalence of illicit drug use, cigarette smoking and alcohol drinking behaviour among a sample of high-school adolescents in the Pietersburg area (Central Region) of the Northern Province, South Africa. PARTICIPANTS: Participants in this study were 435 secondary-school adolescent students around the Pietersburg area (Central Region), in the Northern Province. Two hundred and forty-three (56%) participants were female and 192 (44%) were male. They were aged between 15 and 19 years, with the mean age of 17.25 years (S.D.=1.34). Their educational level ranged between standards 7 and 10 (Grades 9-12). INSTRUMENTS: Participants' demographic variables were determined by use of a questionnaire which covered participants personal characteristics such as age and gender, as well as educational level. Illicit drug use, cigarette smoking, and alcohol drinking behaviour were also measured using the questionnaire. RESULTS: Findings of this study indicate the prevalence rate of 19.8% for illicit drug use, 10.6% for cigarette smoking and 39.1% for alcohol consumption among the participants. Both drug use, cigarette smoking and alcohol consumption are associated more with males than with females. The majority of the drug users and cigarette smokers indicated that they do so when they are bored, tired or stressed up, or at parties; and most of those who drink alcohol indicated that they do so at parties, weekends, or any other time. The mean age for first drug use is 14.9 years (S.D.=1.77); 14.54 years (S.D.=1.80) for first cigarette smoking and 15.33 years (S.D.=1.91) for first alcohol consumption. Among those who drink alcohol, 24.1% and 14.1% experience unplanned drunkenness and irritability, respectively. Unplanned drunkenness is associated with males, while unplanned irritability (after drinking alcohol) is not associated with any gender. CONCLUSION: Mental health workers and the law-enforcement agencies should take note of the above findings while planning preventive and therapeutic strategies for the reduction of drug use, cigarette smoking and alcohol use and abuse among adolescents in the area.     

Prospective,randomized evaluation of a cuffed expanded polytetrafluoroethylene graft for hemodialysis vascular access

BACKGROUND: A cuffed expanded polytetrafluoroethylene (ePTFE) hemodialysis graft was developed to address the problem of recurrent stenosis at the graft-vein anastomosis. The purpose of this study was to compare graft patency and blood flow rates of cuffed and noncuffed (standard) ePTFE grafts placed for hemodialysis access. METHODS: Forty-eight patients were prospectively randomized and followed for up to 24 months after placement of a cuffed or standard ePTFE graft for hemodialysis access. Study end points included time to graft failure and blood flow rates on hemodialysis. RESULTS: Risk factors for graft failure were similar in both groups. However, the overall incidence of graft failure was significantly lower in the cuffed ePTFE graft group (P =.039). Graft patency rates in the cuffed versus standard groups were 64% versus 32% at 12 months (P =.037) and 58% versus 21% at 24 months (P =.0213). No cuffed ePTFE graft failed as a result of venous outflow stenosis. Average graft flow rates were similar when first measured 3 months postoperatively (845 mL/min, cuffed vs 715 mL/min, standard; P =.51) but declined more rapidly in the standard group (12 months, 623 vs 253 mL/min [P =.037]; 24 months, 531 vs 121 mL/min [P =.012]). CONCLUSIONS: The cuffed ePTFE graft was associated with increased blood flow rates during hemodialysis and improved graft patency compared with a standard ePTFE graft. Our results suggest a beneficial effect of the cuffed venous geometry for hemodialysis vascular access.     

Subclinical rejection in tacrolimus-treated renal transplant recipients

BACKGROUND: Subclinical rejection, defined as histologic acute rejection in the absence of graft dysfunction, has been suggested as a cause of chronic allograft rejection. In cyclosporine-treated patients, the incidence of subclinical rejection 3 months after transplant is reported to be approximately 30%. The intent of our study was to determine the incidence of subclinical rejection in tacrolimus-treated renal allograft recipients. METHODS: We prospectively studied the incidence of subclinical rejection on surveillance biopsies performed 3 months after transplantation in 114 patients transplanted between September 1, 1998 and November 30, 2000. All patients received tacrolimus, mycophenolate mofetil, and prednisone, and 56% received antibody induction. RESULTS: Subclinical rejection was detected in 2.6% of patients (3/114, 95% confidence interval 0.5-7.5%). Borderline changes were detected in 11% (12/114). Subclinical rejections were treated with bolus methylprednisolone. CONCLUSIONS: The incidence of subclinical rejection early after kidney transplantation is extremely low in tacrolimus-treated patients in whom early rejections are aggressively treated, suggesting that surveillance biopsies may not be necessary with this regimen.     

Multicollinearity in prognostic factor analyses using the EORTC QLQ-C30: identification and impact on model selection

Clinical and quality of life (QL) variables from an EORTC clinical trial of first line chemotherapy in advanced breast cancer were used in a prognostic factor analysis of survival and response to chemotherapy. For response, different final multivariate models were obtained from forward and backward selection methods, suggesting a disconcerting instability. Quality of life was measured using the EORTC QLQ-C30 questionnaire completed by patients. Subscales on the questionnaire are known to be highly correlated, and therefore it was hypothesized that multicollinearity contributed to model instability. A correlation matrix indicated that global QL was highly correlated with 7 out of 11 variables. In a first attempt to explore multicollinearity, we used global QL as dependent variable in a regression model with other QL subscales as predictors. Afterwards, standard diagnostic tests for multicollinearity were performed. An exploratory principal components analysis and factor analysis of the QL subscales identified at most three important components and indicated that inclusion of global QL made minimal difference to the loadings on each component, suggesting that it is redundant in the model. In a second approach, we advocate a bootstrap technique to assess the stability of the models. Based on these analyses and since global QL exacerbates problems of multicollinearity, we therefore recommend that global QL be excluded from prognostic factor analyses using the QLQ-C30. The prognostic factor analysis was rerun without global QL in the model, and selected the same significant prognostic factors as before.     

Development and validation of a literacy assessment tool for persons with diabetes

PURPOSE: This research was conducted to develop a valid, reliable, quick, and nonstigmatizing tool for assessing literacy in the healthcare setting. METHODS: The Literacy Assessment for Diabetes (LAD) instrument was developed as a word recognition test composed of 3 graded word lists in ascending difficulty. This literacy test, which was specific to diabetes, measured a patient's ability to pronounce terms that they would encounter during clinic visits and in reading menu and self-care instructions. The majority of the terms were on a 4th-grade reading level, with the remaining words ranging from the 6th-through 16th-grade levels. To assess reliability and validity, the LAD was compared with the Wide Range Achievement Test (WRAT3) and the Rapid Estimate of Adult Literacy in Medicine (REALM) by administering all 3 tests to 203 participants in a test-retest study design. RESULTS: All 3 tests (LAD, REALM, and WRAT3) reliably detected true intrasubject variation in word recognition from test to retest. In addition, LAD measured word recognition ability similar to the REALM and WRAT3. CONCLUSIONS: The LAD is a reliable and valid instrument for measuring literacy in adults with diabetes. It can be administered in 3 minutes or less, and the raw score is scaled to a reading grade level.