Differential localization of IL-2- and -15 receptor chains in membrane rafts of human T cells

We studied whether cytokine receptors (Rs) on T cells associate with lipid microdomains ("rafts"). Low-dose phytohemagglutinin (PHA)-stimulated human T cells were separated into cytoplasmic, membrane, and raft fractions by buoyant density centrifugation. Examination of these fractions for the presence of interleukin (IL)-2- and -15R chains and associated signaling molecules by Western blotting revealed marked, selective enrichment of the IL-2/15R beta-chain in rafts before IL-2 stimulation. After IL-2 stimulation, a substantial amount of the beta-chain was found in the membrane fraction. This partial translocation was also observed for the beta-chain-associated molecules JAK-1, p56(lck), and grb-2. Finally, raft disruption with methyl-beta-cyclodextrin (MBCD) attenuated IL-2-induced tyrosine phosphorylation events and selectively decreased the surface expression of the IL-2/15R beta-chain detected by flow cytometry. These results show that the IL-2/15R beta-chain is enriched in rafts obtained from low-dose, PHA-stimulated T cells, that IL-2 binding alters this enrichment, and that this enrichment may be functionally relevant as a possible mechanism to ensure cytokine selectivity and specificity.     

Accuracy of reporting endocervical component adequacy--a continuous quality improvement project

Inaccurate reporting of the absence of an endocervical (EC) component on Pap smears often results in slide rescreens, amended reports, clinician dissatisfaction, and sometimes unnecessary repeat smears. Therefore, the accuracy of reporting EC component adequacy was selected as a quality indicator for the laboratory continuous quality improvement program (CQI). The process consisted of problem identification, analysis of the situation, collection of data, implementation of solutions, and evaluation of results. The objective of the study was to determine if the accuracy of reporting EC component adequacy on Pap smears improved after application of such a program. During the first phase, 150 Pap smears originally reported with the absence of an adequate EC component and 150 smears reported with the presence of an adequate EC component were rescreened to measure the baseline accuracy of EC component adequacy reporting. The improvement process was then implemented. A cause-and-effect diagram was developed and root cause was determined. A presentation was then made to the cytology staff. Criteria for EC component adequacy were reviewed, examples were shown, and standardized marking of EC component was implemented. Following improvement actions, a second audit of 150 Pap smears reported with the absence of an adequate EC component as well as 150 smears reported with the presence of an adequate EC component was undertaken to measure change in performance in assessing EC component adequacy. For the baseline rescreening, before initiation of the CQI program, 98% accuracy was achieved with smears that were reported as adequate for EC component present. However, the accuracy with smears reported as absence of an adequate EC component was only 71%, i.e., an adequate EC component was identified in almost 1/3 of these cases on rescreen. After the implementation of improvement actions, the accuracy with smears reported with the presence of EC component remained high (98%) and the accuracy of reporting the absence of EC component was 90%. The difference of the latter before and after the implementation was statistically significant (P = 0.015, z-test). The accuracy of reporting EC component adequacy increased following the CQI process. Using reporting EC component adequacy as an example, we demonstrate that by treating clinical problems as quality control issues and applying basic quality improvement tools, a positive outcome can be effected.     

Lay Attitudes toward Genetic Testing for Susceptibility to Inherited Diseases

One of the most important issues facing legal and medical policy makers in the coming years will be whether to employ populationbased testing for genetic markers of inherited diseases. Two hundred and twenty-six randomly selected individuals from Easton, Pennsylvania completed a mail questionnaire that was designed to assess the general public's attitudes toward many of the personal and societal issues surrounding genetic testing for disease susceptibility. Respondents were generally optimistic about the potential benefits of genetic testing, and their attitudes about genetic testing were associated with their personal interest in getting a genetic test. Respondents were more likely to be interested in undergoing genetic testing for disease susceptibility if they might have some control over the targeted disease (i.e. there was a cure) and if the test was highly predictive of their chances of developing the disease. Respondents were wary of granting access to genetic testing results to anyone other than doctors and family members, and they did not want the government, religious leaders, or the courts involved in regulating genetic testing. These results have important implications for psychologists, genetic scientists, bioethicists, and legal scholars who are grappling with the many issues related to population-based genetic testing for inherited diseases.     

Summary of complementation groups of UV-sensitive CHO cell mutants isolated by large-scale screening

A summary is given for the lineage and complementation groupassignments of 153 UV-sensitive mutants of the CHO AA8 cellline. The distribution of mutants among six complementationgroups was highly non-random, with the great majority of theisolates belonging to groups 1 and 2. This asymmetry is consistentwith the known hemizygosity of these two linked loci in CHOcells. The relative numbers of mutants induced in group 2 wasfound to depend greatly on the type of mutagen used. Mutagenesiswith UV radiation, ethyl methanesulfonate (EMS), N-methyl-N'-nitro-N-nitroso-guanidine and 7-bromomethylbenz[a]anthraceneproduced high frequencies of group 2 mutants. In contrast, ICR170and ICR191, which are thought to produce mostly frameshift mutations,yielded very few mutants in group 2. These results are of particularimportance in light of the recent finding that the human ERCC2gene, which corrects group 2 mutants, has very strong homologywith the yeast gene RAD3. RAD3 is an essential gene for viabilityin yeast, and the low recovery of group 2 mutants using theframeshift agents strongly suggests that frameshift mutationstend to be lethal in the hamster ERCC2 locus. Several mutagen-sensitivedouble mutants were isolated in two-step selections from EMS-,mitomycin C- or UV-sensitive parental cells, including the lineUVU1, the first mammalian line with two mutations that affectUV sensitivity. The first mutation inactivated excision repair,and the second mutation appears to have affected some otherrecovery process. UVU1 should be useful for studying recoveryprocesses that are separate from nucleotide excision repair. ¹To whom correspondence should be addressed     

"Acadian" and "classical" forms of Friedreich ataxia are most probably caused by mutations at the same locus

"Acadian ataxia" is a form of Friedreich ataxia found in individuals of Acadian ancestry. It was described by Barbeau (in Sobue I (ed): Spinocerebellar Degeneration; Tokyo: Univ. Tokyo Press, pp 121-142, 1980) as having a slower course of degeneration and less severe secondary symptoms than "classical" Friedreich ataxia. He suggested that these 2 forms of the disease may be distinct. The mutation causing "classical" Friedreich ataxia has recently been mapped to chromosome 9 through genetic linkage studies, and here we show that the locus causing Friedreich ataxia in Acadian families from southwestern Louisiana is tightly linked to the same DNA marker, D9S15. Thus, these 2 disorders, which may be differentiated clinically, are most probably due to mutation(s) at the same locus on chromosome 9.     

Diversity of aminoglycoside resistance inEnterobacter cloacae in Greece

NinetyEnterobacter cloacae strains isolated from 12 Greek hospitals were examined in terms of epidemiological types and resistance mechanisms. Using O serotyping 69 % of the strains were assigned to a specific serotype and overall 16 different serotypes were identified. The combination of serotyping, phagetyping and biotyping efficiently discriminated most of the strains, indicating that single epidemic strains were not prevalent, although serotypes 3, 7, and group II predominated. Eight representative strains, all resistant to gentamicin, tobramycin, amikacin and netilmicin, were further examined for transferability and mechanisms of resistance. Aminoglycoside resistance was found to be transferable in most strains, and 13 R plasmids of 40–120 MDa molecular weight were detected. The enzymes detected consisted of three enzymes active against gentamicin [ANT(2), AAC(3)-I and AAC(3)-V]; three active against tobramycin [ANT(2), AAC(3)-V and AAC(6)-I]; two active against netilmicin [AAC(3)-V and AAC(6)-I]; and one active against amikacin [AAC(6)-I]. APH(3) and ANT (3), which modify neomycin and streptomycin plus spectinomycin respectively, were also found. Overall up to five aminoglycoside modifying enzymes were detected on the same R plasmid, AAC(6)-I plus ANT(2) being the most prevalent. The high incidence of multiresistance inEnterobacter cloacae and the fact that resistance is due to enzymatic inactivation of the antibiotics, indicate that in Greece this species might act as a gene pool for the spread of resistance to other bacteria of clinical relevance.     

Psychologic predictors of psychosocial and medical outcomes in patients undergoing coronary angioplasty

The relationship between psychologic variables (the match between repressive style and level of cardiac information, and anxiety level) and medical complications, re-stenosis (renarrowing), and psychosocial adjustment was studied in 97 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) for treatment of narrowed coronary arteries. Three major findings emerged for outcomes measured 6 months after PTCA: repressors with a high level of cardiac information (coping style-information level mismatch) and no history of heart attack were at higher risk for late medical complications (p less than 0.001); sensitizers with a low level of cardiac information (coping style-information level mismatch) and whose PTCA was only moderately successful were at higher risk for re-stenosis of the artery previously widened during PTCA (p less than 0.01); and patients who were more anxious during hospitalization had poorer social functioning and more mood disturbance 6 months after PTCA (p less than 0.05). Thus, psychologic, information, and medical factors are important in predicting 6-month outcomes in patients undergoing PTCA.