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A simple method of screening for the common connexin-26 gene 35delG mutation in nonsyndromic neurosensory autosomal recessive deafness.

Mutations in the Connexin-26 gene are responsible for up to 60% of nonsyndromic, neurosensory autosomal recessive deafness (NSRD). Amongst all the mutations described to date, 35delG (a deletion of a G in a tract of five Gs at positions 30-35) is the most common and has been found in virtually all of the populations studied. Because its frequency varies in different populations, a rapid and simple method of detection of this mutation would be very helpful in population studies. A wide variety of methods for this detection have been described, but we herein present a very simple method using a PCR with primers designed to provide an amplicon of 94 or 93 nucleotides for the normal or mutant alleles, respectively, that can be easily distinguished in an 8% polyacrylamide gel. The entire protocol can be completed in a morning, thus supporting multiple runs. This assay will be useful in screening the large sample sizes required for population studies.

Base Sequence↗

Synthesis, pharmacology and molecular modeling of N-substituted 2-phenyl-indoles and benzimidazoles as potent GABA(A) agonists.

Among the known non-benzodiazepine hypnotic drugs, Zolpidem (1a), Indiplon (2a) and Zaleplon (2b) have shown high affinity and selectivity for the alpha(1) subunit of the GABA-A receptor. Our group has performed pharmacophoric and ADMET-prediction studies to evaluate a virtual library of new molecules based on privileged structures. Among these, we have synthesized a library of N-substituted indoles and a library of N-substituted benzimidazoles. Afterwards, in vitro screening and in vivo spontaneous motor activity in mice has revealed molecules with good in vitro affinities for the alpha(1) receptor and potent in vivo induction of sedation.

Benzimidazoles↗

Human protein tyrosine phosphatase-like gene: expression profile, genomic structure, and mutation analysis in families with ARVD.

The mouse protein tyrosine phosphatase-like gene (Ptpla) was recently cloned and data suggested that it plays a role in myogenesis and cardiogenesis. The human homologue (PTPLA) was mapped to chromosome 10p13-14, a region where we have mapped a locus responsible for arrhythmogenic right ventricular dysplasia (ARVD). As a positional candidate gene, we characterized PTPLA by determining its tissue expression, its genomic structure, and we also screened for mutations in the ARVD patients. Northern analysis demonstrated PTPLA is preferentially expressed in both adult and fetal heart. A much lower expression was detected in skeletal and smooth muscle tissues. Virtually no expression was observed in other tissues. The protein-encoding sequences of PTPLA consist of seven exons. A sequence variation (Lys64Gln) was found in all the affecteds in a large ARVD family. However, the same variant was also detected in normal control subjects (three alleles/100 chromosomes). Thus, the variant (Lys64Gln) is not responsible for ARVD in our family and is a benign polymorphism. Nevertheless, its tissue-specific expression in the developing and adult heart suggest PTPLA has a role in regulating cardiac development, differentiation, or other cellular events. The genomic structure and intragenic polymorphism of PTPLA should be useful for further clinical and genetic studies such as gene targeting of PTPLA.

Arrhythmogenic Right Ventricular Dysplasia↗

A protein trap strategy to detect GFP-tagged proteins expressed from their endogenous loci in Drosophila.

In Drosophila, enhancer trap strategies allow rapid access to expression patterns, molecular data, and mutations in trapped genes. However, they do not give any information at the protein level, e.g., about the protein subcellular localization. Using the green fluorescent protein (GFP) as a mobile artificial exon carried by a transposable P-element, we have developed a protein trap system. We screened for individual flies, in which GFP tags full-length endogenous proteins expressed from their endogenous locus, allowing us to observe their cellular and subcellular distribution. GFP fusions are targeted to virtually any compartment of the cell. In the case of insertions in previously known genes, we observe that the subcellular localization of the fusion protein corresponds to the described distribution of the endogenous protein. The artificial GFP exon does not disturb upstream and downstream splicing events. Many insertions correspond to genes not predicted by the Drosophila Genome Project. Our results show the feasibility of a protein trap in Drosophila. GFP reveals in real time the dynamics of protein's distribution in the whole, live organism and provides useful markers for a number of cellular structures and compartments.

Animals↗

Sirius red histophotometry and spectrophotometry of sections in the assessment of the collagen content of liver tissue and its application in growing rat liver.

By means of staining with Sirius Red F3BA in a saturated picric acid solution, the collagen contents of rat livers with varying degrees of fibrosis have been measured quantitatively in fixed and sectioned material, using both histophotometry in situ and extraction of bound dye with colorimetric analysis. These findings have been correlated with chemical assays of the hydroxyproline content in homogenates from the same livers. It appears that a highly significant correlation exists between both section-based analysis methods and the hydroxyproline content, the Spearman-Rank correlation coefficients being virtually identical. For analysis of collagen accumulation in rat liver, both section-based methods seem to be useful and reliable, the extraction method giving the quickest results for large-scale screening, and the histophotometric method being more appropriate to take readings in selected areas. With human liver material, indications have been obtained for the existence of large sampling errors due to inhomogeneous distribution of collagen deposits. Using the extraction method, no significant changes could be observed in the volume density of collagen during postnatal growth from 1 week to 21 months in rat liver: only on the third day after birth was a higher value of collagen/total protein obtained, possibly due to a higher water content of the hepatocytes. Partial hepatectomy was found to have no influence at all on the collagen content of rat liver during the period of restorative growth or after it.

Animals↗

Testing the proficiency to distinguish locations with elevated plantar pressure within and between professional groups of foot therapists.

BACKGROUND: Identification of locations with elevated plantar pressures is important in daily foot care for patients with rheumatoid arthritis, metatarsalgia and diabetes. The purpose of the present study was to evaluate the proficiency of podiatrists, pedorthists and orthotists, to distinguish locations with elevated plantar pressure in patients with metatarsalgia. METHODS: Ten podiatrists, ten pedorthists and ten orthotists working in The Netherlands were asked to identify locations with excessively high plantar pressure in three patients with forefoot complaints. Therapists were instructed to examine the patients according to the methods used in their everyday clinical practice. Regions could be marked through hatching an illustration of a plantar aspect. A pressure sensitive platform was used to quantify the dynamic bare foot plantar pressures and was considered as 'Gold Standard' (GS). A pressure higher than 700 kPa was used as cut-off criterion for categorizing peak pressure into elevated or non-elevated pressure. This was done for both patient's feet and six separate forefoot regions: big toe and metatarsal one to five. Data were analysed by a mixed-model ANOVA and Generalizability Theory. RESULTS: The proportions elevated/non-elevated pressure regions, based on clinical ratings of the therapists, show important discrepancies with the criterion values obtained through quantitative plantar pressure measurement. In general, plantar pressures in the big toe region were underrated and those in the metatarsal regions were overrated. The estimated method agreement on clinical judgement of plantar pressures with the GS was below an acceptable level: i.e. all intraclass correlation coefficient's equal or smaller than .60. The inter-observer agreement for each discipline demonstrated worrisome results: all below .18. The estimated mutual agreements showed that there was virtually no mutual agreement between the professional groups studied. CONCLUSION: Identification of elevated plantar pressure through clinical evaluation is difficult, insufficient and may be potentially harmful. The process of clinical plantar pressure screening has to be re-evaluated. The results of this study point towards the merit of quantitative plantar pressure measurement for clinical practice.

Adult↗

Breastfeeding: breast milk banks and human immunodeficiency virus.

HIV in infants and children in Zimbabwe is virtually limited to vertical transmission. Less than 5 cases of transfusion acquired HIV infections have been documented to date. Zimbabwe was the third country in the world after the United States, to screen transfusion blood and blood products. The controversy of HIV transmission through breast milk is still far from resolved. In developing countries, breast-milk substitutes for formulae are not only prohibitively expensive but dangerous because of unhygienic and economic constraints. The paper argues the case for continued breast-feeding of infants by their HIV seropositive mothers.

Adult↗

History of posttransfusion hepatitis.

The risk of hepatitis virus transmission from tranfusions has declined dramatically from that of the 1940s when posttransfusion hepatitis (PTH) was first appreciated. Introduction of hepatitis B surface antigen screening and conversion to volunteer donors for whole-blood donations in the late 1960s and early 1970s led to substantial reduction in PTH cases. However, up to 10% of the recipients continued to develop PTH, most cases of which were attributed to an unknown non-A, non-B viral agent. Implementation of surrogate marker testing (i.e., alanine aminotransferase and anti-hepatitis B virus core antigen) for residual non-A, non-B hepatitis in the late 1980s reduced the per unit risk of PTH from 1 in 200 to about 1 in 400. Hepatitis C virus was discovered in 1989 and quickly was established as the causative agent of > 90% of non-A, non-B PTH. Introduction of progressively improved antibody assays in the early 1990s reduced the risk of PTH due to hepatitis C virus to about 1 in 100000. Although additional hepatitis viruses exist (e.g., hepatitis G virus), these appear to be minor contributors to clinical PTH, which has been virtually eradicated.

Alanine Transaminase↗

New evidence from Le Moustier 1: computer-assisted reconstruction and morphometry of the skull.

In this study, we present a new computerized reconstruction of the Le Moustier 1 Neanderthal skull and discuss its significance for Neanderthal growth and variability. Because of the precarious state of preservation of the original material, we applied entirely noninvasive methods of fossil reconstruction and morphometry, using a combination of computed tomography, computer graphics, and stereolithography. After electronic restoration, the isolated original pieces were recomposed on the computer screen using external and internal anatomical clues to position the bone fragments and mirror images to complete missing parts. The inferred effects of general compressive deformation that occurred during fossilization were corrected by virtual decompression of the skull. The resulting new reconstruction of the Le Moustier 1 skull shows morphologic features close to the typical Neanderthal adult state. Residual asymmetry of skeletal parts can be traced to in vivo skeletal modification: the left mandibular joint shows signs of a healed condylar fracture, and the anatomy of the occipital region suggests mild plagiocephaly. Using micro-CT analysis, the left incus could be recovered from the matrix filling of the middle ear cavity. Its morphometric dimensions are similar to those of the La Ferrassie III incus. The morphometric characteristics of the inner ear deviate substantially from the condition reported as typical for Neanderthals and fall within the range of modern human variability.

Animals↗

Detection and prevention of uterine cancer.

The two major uterine cancers, squamous carcinoma of the cervix and adenocarcinoma of the endometrium, are highly vulnerable to detection technology and, therefore, secondary prevention. High risk groups for each have been defined, cancer precursors described, i.e., dysplasia of the cervix and adenomatous hyperplasia of the endometrium, and efficient screening methods made available. For the cervical tumor cytologic testing is most appropriate, while histologic screening is more efficient for endometrial precursor lesions. The strategies of approach of these accessible tumors are models for detection and prevention methods elsewhere in the body and we should exploit them to virtual eradication of these uterine tumors.

Carcinoma↗

Drug testing: technical complications of a complex social issue.

To control the adverse effects of substance abuse, urinary drug testing has become common practice in some occupational settings. Although it is virtually impossible to assess accurately the impact of drug abuse at work, increased accidents and absenteeism as well as impaired productivity have been attributed to drug abuse. The major analytical techniques used to screen for illegal drug use are thin-layer chromatography and enzyme- and radioimmunoassays. Gas chromatography-mass spectrometry is uniformly recommended to confirm any positive screening test. The major technical problem in interpreting screening tests is that the presence of a substance in the urine indicates merely exposure to the drug, not necessarily intoxication, habituation, or addiction. Since no certifying criteria are available to insure quality control among laboratories performing urinary drug testing, results may vary widely. In fact, a study conducted by the Centers for Disease Control suggests that poor performance of some laboratories may adversely affect the treatment of drug abuse. The Federal Rehabilitation Act (1973, section 504) prohibits discrimination against the handicapped, which includes both drug abuse and alcoholism. Legal challenges to urinary drug testing have focused on issues related to the right to privacy and freedom from unreasonable searches. Because of the wide-ranging legal, ethical, and medical ramifications of drug-screening programs, careful review of these issues is recommended before an organization establishes such a program.

Alcoholism↗

The T cell receptor V beta 6 domain imparts reactivity to the Mls-1a antigen.

A monoclonal antibody secreting hybridoma was established by fusing spleen cells from a rat immunized with a murine T cell clone, OI11, which has I-Ab restricted specificity for the male H-Y antigen and unrestricted specificity for the minor lymphocyte stimulating antigen, Mls-1a, to the mouse myeloma P3X63AG8.653 and screening for the capacity of the hybridoma supernatants to stimulate the OI11 T cell clone. An antibody (RR4-7) was found to be specific not only for the immunizing T cell clone but virtually for all T cells using the V beta 6 TCR gene product as part of their surface antigen receptor. When the expression of the V beta 6 gene in various strains of mice was analyzed, it was found that strains expressing the Mls-1a antigen contained few T cells expressing V beta 6-encoded TCRs. The majority of T cell hybridomas which expressed V beta 6-encoded TCRs were found to be reactive to the Mls-1a antigen. These data confirm the finding of H. R. MacDonald et al. (Nature (London) 332, 40, 1988) that most TCRs encoded by the V beta 6 gene have a biased specificity for the Mls-1a antigen.

Animals↗

Absence of somatic alterations of the EB1 gene adenomatous polyposis coli-associated protein in human sporadic colorectal cancers.

The human EB1 gene product was recently found, by a yeast two-hybrid screening, to be associated with the carboxy terminus of the APC (adenomatous polyposis coli) protein, the product of a tumour-suppressor gene thought to act as a gatekeeper in colorectal carcinogenesis. Because virtually all of the APC mutations result in the synthesis of carboxy-terminal truncated proteins, mutant APC proteins are expected to lose their ability to interact with EB1 gene product. Thus, the interaction between APC and EB1 proteins may be important for the tumour-suppressor activity of APC protein, and raises the hypothesis that EB1 is also involved in sporadic colorectal tumorigenesis. To investigate this hypothesis, somatic mutations in the entire coding sequence of EB1 cDNA were searched by reverse transcriptase single-strand conformational polymorphism (SSCP) analysis in 21 sporadic colorectal cancers and seven adenomas. None of these tumours contained somatic mutation, whereas a silent cDNA variant was identified in 14% of alleles. Furthermore, to investigate whether EB1 locus was included within a region subjected to losses of heterozygosity, four polymorphism markers surrounding EB1 locus were surveyed. Only one out of 28 colorectal tumours contained a loss of heterozygosity at the D20S107 marker. In conclusion, the present findings strongly suggest that EB1 gene is not involved in somatic colorectal carcinogenesis.

Adenomatous Polyposis Coli↗

Virtual endoscopy--comparison with colonoscopy in the detection of space-occupying lesions of the colon.

BACKGROUND AND STUDY AIMS: A new technique has been described which combines abdominal helical computed tomography (CT) scanning and virtual reality computer technology, known as virtual colonoscopy (VC); the reconstructed images provide a simulation of the interior of the colon as viewed by endoscopy. We compared VC with conventional colonoscopy in patients with suspected or known colonic neoplasia. PATIENTS AND METHODS: A total of 38 patients, in whom there was a high likelihood of colonic polyps or cancer, underwent a noncontrast helical CT scan of the abdomen and pelvis after regular colonoscopy bowel preparation. The images were reconstructed into a VC presentation and compared with the subsequent conventional colonoscopy in a blinded manner. RESULTS: Conventional colonoscopy identified a total of 24 polyps 5 mm or greater. VC correctly identified five of 13 polyps 5-9 mm in size, and ten of 11 lesions greater than or equal to 10 mm in diameter. The reasons for four missed lesions were identified as being secondary to a collapsed rectum in two patients and stool in the right colon in two patients. The sensitivity and specificity per patient of VC for lesions greater than or equal to 5 mm were 66.7% and 75.0% respectively, and for lesions greater than 1 cm were 90.0% and 82.1%, respectively. CONCLUSIONS: Virtual colonoscopy is feasible, well tolerated, and capable of detecting most lesions greater than 10 mm in diameter. This technique is continuing to be developed and warrants further evaluation as a diagnostic and screening tool in colorectal neoplasia.

Adult↗

Antipsychotic-induced type 2 diabetes: evidence from a large health plan database.

Case evidence suggests that some of the atypical antipsychotics may induce type 2 diabetes. The objective of this study was to evaluate the association of antipsychotic treatment with type 2 diabetes in a large health plan database. Claims data for patients with psychosis within a health plan of nearly 2 million members were analyzed using logistic regression. Frequencies of newly treated type 2 diabetes in patients untreated with antipsychotics and among patients treated with quetiapine, risperidone, olanzapine, and conventional antipsychotics were compared. Based on exposure measured in months of antipsychotic treatment, quetiapine and risperidone patients had estimated odds of receiving treatment for type 2 diabetes that were lower than those of patients untreated with antipsychotics (not statistically significant); patients treated with conventional antipsychotics had estimated odds that were virtually equivalent to those of patients untreated with antipsychotics; olanzapine alone had odds that were significantly greater than those of patients untreated with antipsychotics (P = 0.0247). Odds ratios based on 8 months of screening for pre-existing type 2 diabetes and assuming 12 months of antipsychotic treatment were: risperidone = 0.660 (95% CI 0.311-1.408); olanzapine = 1.426 (95% CI 1.046-1.955); quetiapine = 0.976 (95% CI 0.422-2.271); and conventional antipsychotics = 1.049 (95% CI 0.688-1.613). Case reports, prospective trials, and other retrospective studies have increasingly implicated olanzapine and clozapine as causing or exacerbating type 2 diabetes. Few have implicated risperidone while evidence on quetiapine has been limited. This study supports earlier findings on risperidone versus olanzapine and builds evidence on quetiapine. Additional studies are needed to evaluate the association of antipsychotic treatment with type 2 diabetes.

Adult↗

Bacteriostatic, fungistatic, and algistatic activity of fatty nitrogen compounds.

A total of 164 fatty nitrogen compounds, consisting of quaternary ammonium compounds, alkylamines, N-alkyl-1, 3-propylene diamines, substituted amino hydroxystearonitriles, substituted amino hydroxystearyl amines, and nitrogen-containing surfactants, were screened for bacteriostatic, fungistatic, and algistatic activity. The most active compounds were dodecylamine and dodecylamine acetate. A number of compounds were very active against gram-negative bacteria. Most of the surfactants were virtually nontoxic to all of the test organisms.

Amines↗

Hepatitis C markers in hemodialysis patients.

The prevalence of hepatitis C virus (HCV) infection among the patients of a hemodialysis unit in Taiwan was determined by an immunoblot and reverse transcriptase-polymerase chain reaction algorithm to be 58.8% (67 of 114 patients) after serological surveys with two advanced-generation enzyme-linked immunosorbent assays (ELISAs) for anti-HCV and a C 100-3 single-antigen test. The results of the second-generation ELISAs, the supplementary immunoblot test, and the test for HCV RNA were in good agreement with each other, from 86.0 to 98.2%. The first-generation C 100-3 test lacked the sensitivity of the four other systems. The two advanced-generation screening ELISAs for anti-HCV, a multiple-recombinant-antigen test, the Abbott second-generation ELISA, and a synthetic peptide multiple-antigen test, the UBI HCV EIA, provided reliable and virtually equivalent detection of potentially infected blood. Antibodies to capsid 1 and capsid 2 determinants of the Liatek immunoblot system were the most frequently detected reactivities to HCV in the HCV-infected hemodialysis patients. The percentage of HCV-infected patients with abnormal liver function (alanine aminotransferase level, greater than 100 IU/liter) was higher than that of the uninfected patients. The prevalence of HCV infection was correlated to the duration of hemodialysis treatment and the amount of blood transfused, and the most common transmission mode was thought to be patient-to-patient transmission through the dialysis equipment. Several means of reducing the frequency of transmission between hemodialysis patients are suggested.

Adult↗

Natural products and antifungal drug discovery.

The need for new antifungal agents continues, fueled by opportunistic infections in immune-compromised patients and by the development of resistance to existing agents. Natural products offer a virtually unlimited source of unique molecules and not only serve as a reservoir for new potential drugs and drug prototypes, but also for probes of fungal biology. In this chapter, whole-cell screening methods targeted for natural products are illustrated, including general microplate-based screening, bioautography, and mode of action studies, including the use of genetically altered fungal strains now available commercially.

Antifungal Agents↗