Mutation analysis using the restriction site mutation (RSM) assay

Although two decades of research suggests that the hippocampus plays a special role in place learning, the present paper describes a series of studies using swimming pool spatial tasks that show that hippocampal rats have considerable place learning ability, which includes the abilities of finding, remembering, and searching for places. The same studies also show that when environmental cues are uninformative, as is the case early in original learning and again in reversal learning, hippocampal rats are impaired. Since control rats quickly resolve spatial ambiguity in these situations, it is argued that they must have a system with which they can calibrate spatial cues. The discussion considers the possibility that they use dead reckoning with path integration, a spatial strategy that provides guidance based on cues generated by a point of reference and subsequent self-movement and not the cues in the environment through which they are moving. With path integration an animal can monitor its location and at the same time attach spatial meaning to cues that it encounters. An ability to recalibrate external cues may provide the tuning that allows control rats to quickly acquire place responses while hippocampal rats are constrained by the processes of associative learning.     

Child development and emergent literacy

Emergent literacy consists of the skills, knowledge, and attitudes that are developmental precursors to reading and writing. This article offers a preliminary typology of children's emergent literacy skills, a review of the evidence that relates emergent literacy to reading, and a review of the evidence for linkage between children's emergent literacy environments and the development of emergent literacy skills. We propose that emergent literacy consists of at least two distinct domains: inside-out skills (e.g., phonological awareness, letter knowledge) and outside-in skills (e.g., language, conceptual knowledge). These different domains are not the product of the same experiences and appear to be influential at different points in time during reading acquisition. Whereas outside-in skills are associated with those aspects of children's literacy environments typically measured, little is known about the origins of inside-out skills. Evidence from interventions to enhance emergent literacy suggests that relatively intensive and multifaceted interventions are needed to improve reading achievement maximally. A number of successful preschool interventions for outside-in skills exist, and computer-based tasks designed to teach children inside-out skills seem promising. Future research directions include more sophisticated multidimensional examination of emergent literacy skills and environments, better integration with reading research, and longer-term evaluation of preschool interventions. Policy implications for emergent literacy intervention and reading education are discussed.     

Metered-dose inhaler to deliver methacholine in bronchial provocation testing: a pilot study

BACKGROUND: Nonspecific bronchial provocation tests may be simplified by the use of hand-held devices to deliver methacholine. OBJECTIVE: To study the feasibility of using a metered-dose inhaler (MDI) to administer methacholine in bronchial provocation tests, and the ability of such a device to diagnose bronchial hyperresponsiveness (BHR) accurately. METHODS: In an open randomized crossover pilot study, we compared the provocative dose that induces a 20% fall in FEV1 (PD20 FEV1) obtained with the methacholine MDI with that obtained using a conventional nebulizer in 20 hyperresponsive and 20 nonhyperresponsive subjects. The MDI delivers 400 doses of 100 microg of methacholine, and was used via a spacer. Bronchial hyperresponsiveness (BHR) was defined as a PD20 FEV1 <2,000 microg with the conventional test using the nebulizer. The tests were performed in each subject in a randomized order, 1 to 7 days apart. RESULTS: Of the subjects who had a nebulizer PD20 FEV1 <2,000 microg, all but one had an MDI PD20 FEV1 <800 microg. When 800 microg was taken as the threshold for the diagnosis of BHR with the MDI test, the accuracy of this test to diagnose BHR was 97.5%, and the two tests were highly concordant for the diagnosis of BHR (Pearson chi2, 36.19; p<0.0001). CONCLUSION: A hand-held device may be suitable for delivery of methacholine during bronchial provocation tests, if these results are confirmed in large samples.     

Comparison of 5-fluoro-2'-deoxyuridine with 5-fluorouracil and their role in the treatment of colorectal cancer

Despite more than 30 years of intensive studies on new drugs against advanced colorectal cancer, the fluoropyrimidines remain the drugs of choice for systemic treatment and for hepatic artery infusion (HAI). This overview describes new developments in advanced colorectal cancer chemotherapy, providing a rationale for more effective use of the fluoropyrimidines, with biochemical modulation, scheduling or by revealing biochemical mechanisms of action that correlate with antitumour activity. In human colorectal cancer cell lines and various animal tumour model systems 5-fluoro-2'-deoxyuridine (FdUrd) is more effective than 5-fluorouracil (5-FU). Comparably, FdUrd's modulation by leucovorin (LV) is more potent than 5-FU. In animal studies it is shown that intermittent high-bolus administration of FdUrd generates better antitumour activity, compared with equal toxic doses or any other schedule of 5-FU. These effects are related to prolonged-thymidylate synthase (TS) inhibition and the prevention of TS induction, rather than RNA incorporation. Preclinical studies with modulators such as N-phosphonacetyl-L-aspartate (PALA), WR-2721, mitomycin C and platinum derivatives provide a rationale for clinical use in the future. The first choice systemic chemotherapy of patients with advanced colorectal cancer remains 5-FU combined with LV. Some improvement in therapeutic efficacy has been achieved with locoregional HAI. In randomised studies HAI FdUrd improves the quality of life and survival as compared with optimal systemic therapy. Chronomodulation decreases toxicity, allowing dose intensification, while modulators such as LV or dexamethasone increase survival of patients treated with HAI FdUrd to 86% after 1 year. In conclusion, the clinical use of FdUrd has not been fully explored. Intermittent high-dose FdUrd, chronomodulation together with the use of modulators or drugs focused on prolonged TS inhibition, should be studied in large randomised studies.     

Design and synthesis of small semi-mimetic peptides with immunomodulatory activity based on myelin basic protein (MBP)

Bile reflux has been implicated in the pathogenesis and malignant degeneration of Barrett's esophagus, but clinical studies in patients with adenocarcinoma arising in Barrett's esophagus are lacking. Ambulatory esophageal measurement of acid and bile reflux was performed with the previously validated fiberoptic bilirubin monitoring system (Bilitec) combined with a pH probe in 20 asymptomatic volunteers, 19 patients with gastroesophageal reflux disease (GERD) but no mucosal injury, 45 patients with GERD and erosive esophagitis, 33 patients with GERD and Barrett's esophagus, and 14 patients with early adenocarcinoma arising in Barrett's esophagus. Repeat studies were done in 15 patients under medical acid suppression and 16 patients after laparoscopic Nissen fundoplication. The mean esophageal bile exposure time showed an exponential increase from GERD patients without esophagitis to those with erosive esophagitis and benign Barrett's esophagus and was highest in patients with early carcinoma in Barrett's esophagus (P <0.01). Pathologic esophageal bile exposure was documented in 18 (54.5%) of 33 patients with benign Barrett's esophagus and 11 (78.6%) of 14 patients with early adenocarcinoma in Barrett's esophagus. Nissen fundoplication but not medical acid suppression resulted in complete suppression of bile reflux. Bile reflux into the esophagus is particularly prevalent in patients with Barrett's esophagus and early cancer. Bile reflux into the esophagus can be completely suppressed by Nissen fundoplication but not medical acid suppression alone.     

Measurement of walking endurance and walking velocity with questionnaire: validation of the walking impairment questionnaire in men and women with peripheral arterial disease

This paper presents an application of the continuous wavelet transform (CWT) in the analysis of electrogastrographic (EGG) signals. Due to the nonstationary nature of EGG signals, the CWT method, which uses multiresolution scaled windows, gives a better time-frequency resolution than the short-time Fourier transform, which uses a fixed window. Spike activity due to gastric contraction was investigated through experiments on dogs. During spike activity we observed an increase in magnitude of the slow wave and the appearance of a low frequency component with half the frequency of the slow wave. Studies of the EGG signals from the small intestine are also presented to investigate the hypothesis that its slow wave might be confounded with spike activity in the stomach due to the similarity of their frequency ranges.     

Localized mucosal involvement and severe pulmonary involvement in a young patient with paraneoplastic pemphigus associated with Castleman''s tumour

OBJECTIVES: This study examined the impact of state legislation on mammography quality and access in Michigan. METHODS: The impact of state legislation was analyzed with respect to utilization, numbers of machines and facilities, and image quality. RESULTS: The legislation had a positive effect on image quality improvement, had no impact on utilization by women aged 50 years and above, and resulted in few facility closures. CONCLUSIONS: Michigan's legislative intervention appears to have had a positive effect on efforts to improve mammography quality assurance with implications for other federal and state efforts to achieve quality assurance in health care delivery.     

Pathogenesis of adenocarcinoma in Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is an autosomal dominant condition characterized by intestinal hamartomatous polyps, mucocutaneous melanin deposition, and increased risk of cancer. Families with PJS from the Johns Hopkins Polyposis Registry were studied to identify the molecular basis of this syndrome and to characterize the pathogenesis of gastrointestinal hamartomas and adenocarcinomas in PJS patients. Linkage analysis in the family originally described by Jeghers in 1949 and five other families confirmed linkage to 19p13.3 near a recently identified gene responsible for PJS. Germ-line mutations in this gene, STK11, were identified in all six families by sequencing genomic DNA. Analysis of hamartomas and adenocarcinomas from patients with PJS identified loss of heterozygosity (LOH) of 19p markers near STK11 in 70% of tumors. Haplotype analysis indicated that the retained allele carried a germ-line mutation, confirming that STK11 is a tumor suppressor gene. LOH of 17p and 18q was identified in an adenocarcinoma but not in hamartomas, implying that allelic loss of these two regions corresponds to late molecular events in the pathogenesis of cancer in PJS. The adenocarcinomas showing 17p LOH also demonstrated altered p53 by immunohistochemistry. None of the 18 PJS tumors showed microsatellite instability, LOH on 5q near APC, or mutations in codons 12 or 13 of the K-ras proto-oncogene. These data provide evidence that STK11 is a tumor suppressor gene that acts as an early gatekeeper regulating the development of hamartomas in PJS and suggest that hamartomas may be pathogenetic precursors of adenocarcinoma. Additional somatic mutational events underlie the progression of hamartomas to adenocarcinomas, and some of these somatic mutations are common to the later stages of tumor progression seen in the majority of colorectal carcinomas.     

A complex program of striatal gene expression induced by dopaminergic stimulation

Dopamine acting in the striatum is necessary for normal movement and motivation. Drugs that change striatal dopamine neurotransmission can have long-term effects on striatal physiology and behavior; these effects are thought to involve alterations in gene expression. Using the 6-hydroxydopamine lesion model of Parkinson's disease and differential display PCR, we have identified a set of more than 30 genes whose expression rapidly increases in response to stimulation of striatal dopamine D1 receptors. The induced mRNAs include both novel and previously described genes, with diverse time courses of expression. Some genes are expressed at near-maximal levels within 30 min, whereas others show no substantial induction until 2 hr or more after stimulation. Some of the induced genes, such as CREM, CHOP, and MAP kinase phosphatase-1, may be components of a homeostatic response to excessive stimulation. Others may be part of a genetic program involved in cellular and synaptic plasticity. A very similar set of genes is induced in unlesioned animals by administration of the psychostimulant cocaine or the antipsychotic eticlopride, although in distinct striatal cell populations. In contrast to some previously described early genes, most of the novel genes are not induced in cortex by apomorphine, indicating specificity of induction. Thus we have identified novel components of a complex, coordinated genetic program that is induced in striatal cells in response to various dopaminergic manipulations.     

An in vitro comparison between laser fluorescence and visual examination for detection of demineralization in occlusal pits and fissures

Metabolism of xenobiotics such as alcohol and organic solvents can be divided roughly into two types: functional and conjugation reactions. Cytochrome P450 (CYP) is the primary group of enzymes involved in the former. Therefore, CYP analysis is essential for the study of the metabolism and toxicity of these chemicals. Of the isozymes, CYP2E1 is a low-km isozyme and has a high affinity for volatile hydrocarbons of low molecular mass, and is primarily involved in the metabolism of alcohol and organic solvents. There are many methods for analysis of CYPs including CYP2E1. The measurement of the metabolic rate of the target chemical in the liver is the most common. When combined with monoclonal or polyclonal antibody to CYP, contribution of the isozymes to the metabolism can be resolved, and the expression level is also identified by western blot analysis. The use of the reconstituted system of purified CYP isozymes is useful to determine the true activity (specific activity), but not common especially in that of human tissue. There are sometimes species differences in the enzymatic character of CYP isoforms, which causes difficulties in extrapolating to humans. In these case, the use of a cDNA expression system of human CYPs can cover the difficulties. The use of transgenic animals can answer the contribution of each CYP isoform in the in vivo metabolism and toxicity. The genotype of each isozyme is analyzed by PCR method, which can identify the polymorphism as well as the susceptibility to the chemicals.