The complete sequence of the coding region of the ATM gene reveals similarity to cell cycle regulators in different species

Ataxia-telangiectasia (A-T) is an autosomal recessive disorderinvolving cerebellar degeneration, immunodeficiency, radiationsensitivity, and cancer predisposition. A-T heterozygotes aremoderately cancer prone. The A-T gene, designated ATM, was recentlyidentified in our laboratory by positional cloning, and a partialcDNA clone was found to encode a polypeptide with a PI-3 kinasedomain. We report here the molecular cloning of a cDNA contigspanning the complete open reading frame of the ATM gene. Thepredicted protein of 3056 amino acids shows significant sequencesimilarities to several large proteins in yeast, Drosophilaand mammals, all of which share the PI-3 kinase domain. Manyof these proteins are involved in the detection of DNA damageand the control of cell cycle progression. Mutations in theirgenes confer a variety of phenotypes with features similar tothose observed in human A-T cells. The complete sequence ofthe ATM gene product provides useful clues to the function ofthis protein, and furthers understanding of the pleiotropicnature of the A-T mutations.     

Familial Mediterranean fever gene and protection against asthma.

BACKGROUND: Asthma is an inflammatory airway disease caused by interaction between susceptibility genes and diverse environmental factors. In Israel, asthma seems to be familial and more severe in patients of Iraqi Jewish descent. On the other hand, asthma is less frequent in individuals with familial Mediterranean fever, an autoinflammatory disease prevalent in the Iraqi Jewish community and linked to mutations in the familial Mediterranean fever gene, designated MEFV. OBJECTIVES: To explore a possible role for mutated MEFV in the reduced susceptibility to asthma and to determine its expression in Israeli subjects of Iraqi origins. METHODS: Using a case-control approach, we studied the presence of the 3 most common MEFV mutations (M694V, V726A, and E148Q) in DNA samples from 75 patients with asthma and 45 asymptomatic first-degree relatives, all of Iraqi Jewish origin. The severity of asthma was evaluated using a published severity score. RESULTS: Eleven patients with asthma and 14 of their relatives carried 1 or 2 mutations in the MEFV gene, a carrier rate significantly lower in patients with asthma than in their first-degree relatives and in ethnically matched healthy individuals (P < .03 and P < .003, respectively). Carriers of MEFV mutations had less severe disease, compared with noncarriers (P < .002). CONCLUSION: These findings suggest that MEFV mutations may have a protective effect in the pathogenesis of asthma.     

A novel system to diagnose cutaneous adverse drug reactions employing the cellscan--comparison with histamine releasing test and Inf-gamma Releasing Test

Background: There are several mechanisms to describe allergic drug reactions yet the methods to diagnose them are limited. Objective: To compare several conventional clinical and laboratory methods to diagnose skin reactions to drugs to a new method of diagnosing drug reactions by the CellScan system. Methods: The study entailed 21 patients who were diagnosed as suffering from drug eruptions, and 105 healthy controls with no history of drug allergy. The drugs were classified into two groups according to suspicion of causing drug allergy: high and low. Most of the patients were on more than one drug, leading to 41 patient-drug interactions (assays). Histamine releasing test (HRT), interferon (INF)-γ releasing test and CellScan examination were performed on lymphocytes of the patients and controls. Results: The HRT was interpreted as positive in 9 out of 18 (50%) patients and in 13 out of 35 (37%) assays. Based on the INF-γ releasing test, positive results were observed in 16 out of 21 (76%) patients and in 24 out of 41 (59%) assays. In the CellScan test (CST), positive results were observed in 17 out of 21 (81%) patients and in 29 out of 41 (71%) assays. The rate of identifying the drug for eruption in the high suspicion level drugs was 9 out of 22 (41%) assays in the HRT, 20 out of 24 (83%) assays in the INF-γ releasing test, and 21 out of 24 (87%) studies with the CellScan method. The rate of determining of the drug that caused the eruption in the low suspicion level drugs was 4 out of 13 (31%) in the HRT, 4 out of 17 (24%) assays in the INF-γ releasing test, and 8 out of 17 (47%) analyses in the CST. When examined in the CellScan, 99 out of 105 (94%) controls were interpreted as negative. Conclusion: This preliminary study indicates that the CellScan seems to be an easy and promising method for the detection of drugs responsible for adverse skin reactions. In contrast to the HRT and to the Interferon-γ secretion test, the CellScan method is characterized by its ability to track and monitor the reaction of individual cells. By measuring the kinetic parameters of selected cells before and after adding the suspected drug, we were able to identify the culprit drug. The CellScan method had the highest sensitivity, and the interferon-γ secretion test had the highest specificity for detection of the culprit drug. In contrast, the analysis of 105 normal control sera disclosed a high specificity of 94% for the CellScan method.     

Reproducibility of skin testing and serum venom specific IgE in Hymenoptera venom allergy.

BACKGROUND: The decision regarding an immunotherapy regimen for venom-allergic patients is based on the results of skin testing and serum venom specific IgE measurements. However, their reliability has been questioned, and their reproducibility has not been examined. OBJECTIVE: To evaluate the reproducibility and reliability of the results of skin testing and serum venom specific IgE measurement in venom-allergic patients. METHODS: Patients with a systemic reaction after an insect sting were evaluated twice, 2 to 6 weeks apart, by intradermal skin tests and by determination of serum venom specific IgE to Hymenoptera venoms. RESULTS: Thirty-five patients were evaluated 1 to 168 months (mean, 23 months) after the sting reaction. Reproducibility of skin test results for all venoms at the 2 sessions was found in 23 patients (66%). Reproducibility of venom specific IgE results for all venoms was found in 16 (59%) of 27 patients from whom 2 blood samples were available for evaluation. Concordance between skin test and venom specific IgE results for all venoms was found in 30 (51%) of 59 samples available for evaluation. CONCLUSIONS: The reproducibility of venom skin test and serum venom specific IgE results is relatively poor. It is common practice for therapeutic decisions regarding venom immunotherapy to be based on a single diagnostic evaluation. Consequently, many patients are either overtreated or undertreated. Better diagnostic methods are required in venom allergy.     

Computerized cognitive testing in patients with type I Gaucher disease: effects of enzyme replacement and substrate reduction.

PURPOSE: Because of concern for drug-induced cognitive dysfunction during clinical trials using substrate reduction therapy (miglustat) in type 1 Gaucher disease and because it has been suggested that some patients with type 1 Gaucher disease may develop neurocognitive impairment as part of the natural history, two different batteries of neuropsychological tests were devised to examine these issues. Using these tests, cognitive function was assessed in patients treated with miglustat, in patients receiving enzyme replacement (standard care for symptomatic patients), and in untreated (milder) patients. METHODS: For this study, 55/60 patients exposed to miglustat in Israel participated in psychologist-administered testing; 36/55 participated in computerized testing. Of these, 31 enzyme-treated patients and 22 untreated patients participated in the psychologist-administered testing, and 15 enzyme-treated patients and 18 untreated patients participated in computerized testing. The psychologist-administered battery consisted of 18 standard neuropsychological subtests specific to executive and visuospatial functioning. The computerized battery (Mindstreams, NeuroTrax Corp., New York, NY) consisted of 10 subtests tapping multiple cognitive domains. Between-group analyses for each modality compared cognitive performance. RESULTS: In the psychologist-administered testing, patients exposed to miglustat performed significantly less well than the other groups in 5/18 subtests. On the computerized tests, all patients performed comparably to normal controls. Scores in patients exposed to miglustat were higher than in untreated patients, particularly in visuospatial function, whereas enzyme-treated patients performed less well. However, with the exception of visuospatial function, these results were not statistically significant. CONCLUSIONS: It is unclear why different testing methods yielded discordant results. Any dysfunction suggested by the current study is apparently subtle and of doubtful clinical relevance given that cognitive status did not interfere with patients' daily intellectual function. The computerized battery has methodological advantages (e.g., language options, objectivity, brevity, and ease of use) that make it well-suited for longitudinal studies, for long-term surveillance of substrate reduction therapy as well as for comparisons with other lysosomal storage disorders and other chronic diseases. These preliminary findings should allay fears of cognitive dysfunction due to short-term miglustat therapy.     

Water diffusion in the different microenvironments of breast cancer

The parameters that characterize the intricate water diffusion in tumors may serve to reveal their distinct pathology. Specifically, the application of diffusion magnetic resonance imaging (MRI) can aid in characterizing breast cancer, as well as monitoring response to therapy. We present here a non-invasive, quantitative MRI investigation, at high spatial resolution, of water diffusion in hormonal dependent MCF7 breast tumors implanted orthotopically in immunodeficient mice. Distinctive MRI protocols were designed in this study, utilizing a broad range of diffusion times and diffusion gradient strengths. Application of these protocols allowed water diffusion in the tissue extracellular and intracellular compartments to be distinguished, and the effect of restricted diffusion and water exchange on the water diffusion in these compartments to be evaluated. Pixel-by-pixel analysis yielded parametric maps of the estimated volume fraction and apparent diffusion coefficient of each compartment. The diffusion of the water in the extracellular microenvironment was approximately two fold slower than that of free water, and in the intracellular compartment was about one order of magnitude slower than that of free water and demonstrated restriction of water diffusion at long diffusion times. Mapping of the water fraction in each compartment was further employed to monitor changes during tumor progression and to assess tumor response to hormonal manipulation with a new antiestrogenic drug, tamoxifen methiodide (TMI). It was found that, in parallel to the growth arrest by this drug, the volume fraction of the slowly diffusing water increased, suggesting a TMI-induced cell swelling. This study can serve as a basis for extending diffusion breast MRI in the clinical setting.     

The great mimicker: Phenotypic overlap between constitutional mismatch repair deficiency and Tuberous Sclerosis complex

Constitutional mismatch repair deficiency is a rare cancer predisposition syndrome caused by biallelic mutations in one of the four mismatch repair genes. Patients are predisposed to various tumors including hematological malignancies, brain tumors and colorectal carcinomas. Phenotypic overlap with Neurofibromatosis-1 is well known, with most patients presenting with café-au-lait macules. Other common features include axillary and/or inguinal freckling and intracranial MRI foci of high T2W/FLAIR signal intensity similar to the typical FASI seen in Neurofibromatosis-1. In this cohort of eight patients with constitutional mismatch repair deficiency we describe overlapping phenotypical features with Tuberous Sclerosis complex. In addition to “ash-leaf like” hypomelanotic macules (five patients), we detected intracranial tuber-like lesions (three patients), renal cysts (three patients) and renal angiomyolipomas (two patients). All our patients also had Neurofibromatosis-1 like features, mainly café-au-lait macules. This study suggests that features of Tuberous sclerosis especially when overlapping with those of Neurofibromatosis 1 or malignancies atypical for these syndromes should raise the possibility of constitutional mismatch repair deficiency. Correct diagnosis is essential for appropriate genetic counseling and pre-emptive cancer surveillance.     

Effects of aging on the novelty P3 during attend and ignore oddball tasks

The effects of attention were assessed on novelty P3 amplitude and scalp distribution elicited by environmental sounds in young and elderly volunteers who participated in either actively attended or ignored oddball conditions. For the young, novelty P3 amplitude decreased with time on task during both attend and ignore sequences. Amplitude decrements were greatest at frontal sites during the attend condition, but at all sites during the ignore condition. A reliable amplitude decrement was not observed for the elderly in either the attend or ignore oddball series. The data suggest that attention differentially activates multiple generators that contribute to scalp-recorded novelty P3 activity. The lack of novelty P3 habituation seen in the elderly is consistent with changes in frontal lobe function as age increases.     

Gene dosage and down's syndrome: Metabolic and enzymatic changes in PC12 cells overexpressing transfected human liver-type phosphofructokinase

Down's syndrome (DS) is a human genetic disease caused by triplication of the distal third of chromosome 21 and overexpression of an unknown number of genes residing in it. The gene for the liver-type subunit of phosphofructokinase (PFKL), a key glycolytic enzyme, maps to this region and the product is overproduced in DS erythrocytes and fibroblasts. These facts, together with abnormalities which occur in DS glycolysis, make PFKL overexpression a candidate for causing some aspects of the DS phenotype. A cellular model for examining the consequences of PFKL overexpression in DS was constructed by transfecting rat PC12 cells with the human PFKL cDNA. Phosphofructokinase (PFK) isolated from PFKL-overexpressing clones was more inhibited by ATP and citrate and less activated by fructose-6-phosphate than control PFK; similar results were obtained when PFK preparations from DS and control fibroblasts were compared. In vivo NMR measurements determined that cells overexpressing PFKL performed glycolysis 40% faster than controls. These results show that overexpression of PFKL is the cause for altered biochemical regulatory characteristics of PFK in DS fibroblasts and can result in enhancement of glycolysis rates. It is also shown that increased gene dosage can exert its influence not merely by enhancing the amounts of gene products but also by altering their biochemical nature.