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Biomedical subjects

B Levin

Publications and source records attributed to B Levin.

428 records · Page 24Linked to original sources

Temporal lobectomy in early childhood.

Children with medically resistant temporal lobe seizures that persist into adolescence often experience psychosocial deterioration and medical morbidity. It is therefore especially important to evaluate the contribution of surgical therapy in preadolescent children. We describe our experience with temporal lobectomy in 16 children less than 12 years (mean age 7 years) who had intractable seizures of temporal lobe origin. Structural lesions were identified on neuroimaging studies in 11 patients. In all patients, the standard anterior temporal lobectomy was tailored according to the extent of the lesion and epileptogenic field. At follow-up, 11 children were seizure-free, three were 90% improved, one was 50% improved, and one was unchanged. Neuropathological abnormalities were identified in virtually all children. Prenatally acquired abnormalities of neurogenesis were the most common, whereas mesial temporal sclerosis was found in only two children. We conclude that tailored temporal lobectomy in the first decade of life is highly beneficial in carefully selected children with medically refractory seizures.

Adult↗

American Cancer Society guidelines for screening and surveillance for early detection of colorectal polyps and cancer: update 1997. American Cancer Society Detection and Treatment Advisory Group on Colorectal Cancer.

In the past, differences in opinion among professional groups about colorectal cancer screening have been a barrier to colorectal cancer prevention. It is clear that screening for colorectal cancer is currently practiced by fewer than 20% of American adults. However, a growing consensus now exists that even though we do not yet have trial data to compare precisely the various methods for screening, there is now both a compelling case for screening and a reasonable set of methods that clinicians and patients can consider. By applying the knowledge we already have, it is likely that most of the deaths from colorectal cancer in the United States could be prevented.

Adult↗

American Cancer Society guidelines for the early detection of cancer: update of early detection guidelines for prostate, colorectal, and endometrial cancers. Also: update 2001--testing for early lung cancer detection.

Updates to the American Cancer Society (ACS) guidelines regarding screening for the early detection of prostate, colorectal, and endometrial cancers, based on the recommendations of recent ACS workshops, are presented. Additionally, the authors review the "cancer-related check-up," clinical encounters that provide case-finding and health counseling opportunities. Finally, the ACS is issuing an updated narrative related to testing for early lung cancer detection for clinicians and individuals at high risk of lung cancer in light of emerging data on new imaging technologies. Although it is likely that current screening protocols will be supplanted in the future by newer, more effective technologies, the establishment of an organized and systematic approach to early cancer detection would lead to greater utilization of existing technology and greater progress in cancer control.

Colorectal Neoplasms↗

Loci for efficient detection of microsatellite instability in hereditary non-polyposis colorectal cancer.

Most hereditary non-polyposis colorectal cancer (HNPCC) is due to germline mutations in DNA mismatch repair genes. Tumors arising as a result of these mutations display instability in microsatellites, which are short tandem repeats of DNA that are distributed throughout the genome. Although a subset of sporadic colorectal carcinomas also have microsatellite instability (MSI), the phenotype is a useful screening test in identifying patients with HNPCC caused by mutations in mismatch repair (MMR) genes. Studies have shown that some microsatellite markers are more efficient than others in identifying tumors with MSI. Furthermore, the frequency of instability can be assessed by categorizing patients into high (MSI-H, >/= 30-40% positive markers), low (MSI-L), and microsatellite stable (MSS) groups. Using a panel of 28 microsatellite markers, tumor and normal DNA from 10 HNPCC patients was used to identify the five most efficient markers for detecting MSI (BAT26, D2S123, FGA, D18S35, and TP53-DI). Each of the five markers detected MSI in 80-100% of the cases examined. We then expanded the sample size to 17 tumors from HNPCC patients. Each case had evidence for a mutation in either hMSH2 or hMLH1. We compared the efficiency of our panel of five best markers with another panel of five markers (BAT25, BAT26, D2S123, D17S250, and D5S346) identified as being efficient markers for detection of MSI at a recent NCI workshop. Our five selected markers were more efficient (85% vs. 79%) in detecting MSI. However, using either panel, 100% of the cases fell into the MSI-H category and the probability of misclassifying an MSI-H case as MSI-L is very low (0.002-0.008). We also examined four cases meeting the Amsterdam criteria for HNPCC, but with no evidence for mutation in either the hMSH2 or hMLH1 gene. With our panel, three were classified as MSI-H, while only two were classified as such with the NCI reference panel. The probability of misclassifying an MSI-L case as an MSI-H, using a panel of five markers is high (0.263).

Basic Helix-Loop-Helix Proteins↗

[Candida carriage in the oral mucosa of a student population: adhesiveness of the strains and predisposing factors].

The aim of this study was to establish oral carriage of Candida and possible factors associated to their virulence in young adults and their relation with local and general situations considered as predisposing factors. Samples were obtained from dorsum tongue in 70 students attending the Faculty of Dentistry (University of Buenos Aires) average age: 23, all in healthy oral conditions. Of these, 21.42% were Candida positive. These samples were seeded in CHROMagar. Candida identification was completed in milk agar and Fungichrom 1. The following species were identified: 11 Candida albicans (C.a), 2 Candida parapsilosis (C.p) and 1 Candida glabrata (C.g). In one case, 2 species (C.a and C.g) were isolated in the same sample. Virulence was determined as adherence capacity by biofilm or in vitro plaque formation and hydrophobicity. Different host factors were analyzed statistically to establish their importance as predisposing factors to allow Candida colonization. Adherence of C.a. was found to be similar in all C.a. strains, whereas significant differences were found between C.a. and C.p. and between C.a. and C.g. Only the antiseptic mouthrinse and the diet were significant among the considered factors.

Adult↗

Sources of variability in normal CA 125 levels.

Two hundred eighty-eight serum specimens from 144 asymptomatic menopausal women were assayed two times each for CA 125. The specimens were randomly assigned to sixteen CA 125 kits. Our purpose was to quantitate the biological variability and the assay variability that occurs at low levels of this tumor marker. All of the subjects had CA 125 values less than 35 units/ml. The total error from all sources was about 13% of the observed values. These findings suggest that single, low CA 125 values are reliable indicators of a woman's true CA 125 value. Clinical trials of ovarian cancer screening that incorporate CA 125 measurements should evaluate the performance of this test at thresholds lower than the usual 35 units/ml.

Adult↗

The role of vitamin D3 in the proliferation of a human colon cancer cell line in vitro.

LoVo, a cultured colon cancer cell line, is shown to possess a receptor for 1,25-dihydroxy vitamin D3 (1 alpha,25(OH)2D3) with a low capacity (28 fmol/mg protein) and high affinity (Kd: 1.9 x 10(-21)0M). When these cells were grown in monolayer culture in a chemically defined serum-free medium, a significant inhibition of proliferation was seen in the presence of 10 nM to 1 microM of 1 alpha,25(OH)2D3 (p less than 0.005. Furthermore, 1 alpha,25(OH)2D3 delayed early attachment of cells. After 8 days of treatment, aggregated cuboidal cells showed a marked change to an apparently spindle like morphology. The 1 alpha,25(OH)2D3 growth-inhibitory effect was modulated by verapamil (1 microM), a calcium channel blocker, hydrocortisone (1 microM), and moxestrol (1 mM), an estrogen analogue, and 2% charcoal-treated fetal bovine serum. This study represents the first demonstration of 1 alpha,25(OH)2D3 modulation of growth of human colon cells.

Calcitriol↗

Aspirin and other nonsteroidal anti-inflammatory drugs and risk of colorectal adenomatous polyps among endoscoped individuals.

Most epidemiological evidence supports the inverse association between use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) and colorectal cancer. Few studies have investigated the relation between use of aspirin and other NSAIDs and adenomatous polyps, which are recognized as precursors of colorectal cancer. We examined the association of adenomatous polyps and the dose and duration of use of aspirin and other NSAIDs in a case-control study of dietary risk factors for colorectal adenomatous polyps. The study population comprised 157 case and 480 control individuals who underwent an endoscopy at collaborating gastroenterology clinics in Houston, TX. Face-to-face interviews were conducted to obtain risk factor data that included information on frequency and duration of use of aspirin and other NSAIDs. Compared to the nonusers, the multivariate odds ratios for individuals who took aspirin and other NSAIDs on a weekly basis and for those who took these once/day or more were 0.77 (95% confidence interval, 0.39-1.55) and 0.36 (95% confidence interval, 0.20-0.63), respectively. Compared to the nonusers, the odds ratio for individuals who used aspirin and other NSAIDs for <5 years was 0.39 (95% confidence interval, 0.39-1.55) and 0.36 (95% confidence interval, 0.20-0.71), and for those who used these for 5 years or more, the odds ratio was 0.60 (95% confidence interval, 0.32-1.14). The results of this study suggest that aspirin and other NSAIDs are associated with a decreased risk for adenomatous polyps. Limited dose-response analyses found that the point estimate decreased with the frequency but not the duration of use of aspirin and other NSAIDs.

Adenomatous Polyps↗