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Biomedical subjects

D Strauss

Publications and source records attributed to D Strauss.

At least 37 records · Page 2Linked to original sources
PubMed1998

Assessment of intersignal variability for discrimination of atrial fibrillation from atrial flutter.

The analysis of endocardial signals obtained from an electrode located in the right atrium enabled by new dual chamber implantable cardioverter defibrillators may be helpful to provide additional therapies such as overdrive pacing or low energy atrial cardioversion for the treatment of concomitant atrial flutter (AFL) or atrial fibrillation (AF). Algorithms for discrimination of atrial tachyarrhythmias based on rate counting are of limited efficacy. The aim of this study was to assess the intersignal variability by using fast discrete wavelet transforms (FDWT) as a new method of discrimination of AF from AFL. Patients with spontaneous episodes of AF/AFL or patients who developed AF/AFL during an electrophysiological study were studied. The endocardial signals were recorded from the high right atrium using a transvenous 5 Fr bipolar electrode catheter (interelectrode spacing: 1 cm). The signals were digitized (2 kHz, 12-bit resolution) after amplification and filtering (40-500 Hz). Within data segments of 10-second duration, 25 consecutive signals were selected and normalized and FDWT was applied. Standard deviations of the wavelet coefficients (SD) from coarse scales (scale 4-8) were calculated. A total of 94 data segments (AF: 52, AFL: 42) from 28 patients were analyzed. SD at each considered scale was higher for AF than for AFL (P < 0.001). SD at scale 8 discriminated between AF from AFL with 100% sensitivity and specificity. We conclude that assessment of intersignal variability of bipolar endocardial recordings using FDWT is an effective method for the discrimination of AF from AFL. The implementation of this tool in a discrimination algorithm of an implantable device may help provide the appropriate differential therapy for atrial tachyarrhythmias.

Algorithms↗
PubMed1998

Discrimination of sinus rhythm, atrial flutter, and atrial fibrillation using bipolar endocardial signals.

INTRODUCTION: Analysis of endocardial signals obtained from an electrode located in the right atrium as realized in newly designed dual chamber, implantable cardioverter defibrillators might be used to provide additional therapeutic options, such as overdrive pacing or low-energy atrial cardioversion for the treatment of concomitant atrial flutter (AFL) or atrial fibrillation (AF). Therefore, we developed a computer algorithm for discrimination of normal sinus rhythm (NSR), AFL, and AF that may lead to adequate differential therapy of atrial tachyarrhythmias in an automated mode. METHODS AND RESULTS: During an electrophysiologic study, bipolar endocardial signals from the high right atrium were obtained in 28 patients during sustained AFL or AF and after restoration of NSR. A total of 286 data segments of 5-second duration were recorded (NSR: 96, AFL: 86, AF: 104). Mean atrial cycle length (MCL), standard deviation of mean atrial cycle length (SDCL), and index of irregularity (IR), defined as the ratio between MCL and SDCL, were calculated for each data segment. A cutoff of 315 msec for MCL allowed discrimination of NSR from atrial tachyarrhythmias with 100% sensitivity and specificity. For discrimination of AF from AFL by using SDCL, a cutoff value of 11.5 msec led to a sensitivity of 99% and a specificity of 90%. Best discrimination of AF from AFL was found for the criterion IR > or = 7.5%, resulting in a sensitivity of 100% with a specificity of 95% for AF detection. CONCLUSION: The investigated algorithm provides discrimination of NSR, AFL, and AF with high sensitivity and specificity. Incorporation of this algorithm in an implantable automated antitachycardia device may lead to adequate differential therapy in patients suffering from spontaneous episodes of AF and AFL.

Algorithms↗
PubMed1998

Mortality of adults with developmental disabilities living in California institutions and community care, 1985-1994.

We compared risk factor-adjusted mortality for California adults with developmental disabilities based on 22,576 adults receiving services in California, 1985-1994. Mortality rates were adjusted for factors such as age and level of functioning. Risk factor-adjusted mortality was 72% higher in community care than in institutions. The mortality pattern over the years 1993-1994, which had not previously been studied, was comparable to that of 1985-1992. The substantially increased risk in community care suggests that community settings may be less effective in preventing mortality in this population.

Adult↗
PubMed1998

Causes of death of persons with developmental disabilities: comparison of institutional and community residents.

Between 1993 and 1995, 1,878 persons transferred from California institutions into the community. By early 1996, 45 had died--significantly more than expected (Strauss, Shavelle, Baumeister, and Anderson, 1998). We report here on the death certificates for this group, using a comparison group of 45 certificates for institutional residents. Thirty-two of the community deaths versus 10 of the institution deaths were "sudden" or "subacute." All of the institution deaths versus 79% of the community deaths were reported to the coroner, and 55% of the institutional deaths were followed by autopsy compared to 33% in the community. Six deaths were due to perforated bowels, 5 of which were in individuals residing in the community.

Adolescent↗
PubMed1998

Mortality in persons with developmental disabilities after transfer into community care.

More than 2,000 persons with developmental disabilities have been transferred from California state institutions into community care in recent years. We investigated whether this has been accompanied by a change in mortality rates, using data on 1,878 clients moved since April 1993. Mortality rates were compared to those expected for comparable persons in institutions. Risk-adjusted mortality rates for movers exceeded institutional rates by 51%, p < .05. After removal of cancer deaths in both groups, this increased to 67%. The effect was largest shortly after the move and in the subjects who had moved most recently. The deinstitutionalization process in California appears to have resulted in a substantial increase in mortality, indicating the need to ensure continuous, consistent, and competent medical care and supervision in the community.

Activities of Daily Living↗
PubMed1998

Life expectancy of persons with chronic disabilities.

The life expectancy is an important summary measure of an individual's prognosis for survival. The life table is the preferred method for computing life expectancies, but it is not always feasible. We show that for several chronic disabilities, the logarithms of the age-specific mortality ratios (relative to the general population) decline linearly with age, reaching parity at age 85 or older. This, combined with a standard modeling of an individual's current mortality rate, yields a set of age-specific mortality rates that can be used to produce a "customized" life table. The life expectancy is then immediately available. In a series of empirical comparisons the method performed better than an assumption of constant excess death rate (EDR), and much better than one of constant mortality ratio (MR). The method may be useful for a variety of non-progressive disabilities, such as cerebral palsy and injuries of the brain or spinal cord.

Adolescent↗
PubMed1998

Comparative mortality of persons with autism in California, 1980-1996.

The authors studied mortality rates of persons with autism, using the extensive California developmental disabilities registry. There was an overall mortality ratio (MR) of 213%. The MR for females (490%) was strikingly higher than for males (167%). The excess mortality rate (EDR) increased with age, while the mortality ratio (MR) decreased with age. Persons with autism are subject to increased mortality risk, as summarized in the provided tables.

Activities of Daily Living↗
PubMed1998

Comparative mortality in cerebral palsy patients in California, 1980-1996.

BACKGROUND: The large database of the California Department of Developmental Services provides a data source for mortality rates in persons with mental retardation by age, sex, severity, cause and associated conditions. This study involves patients with a diagnosis of cerebral palsy. RESULTS: After a table of demographic data, four tables are used to show detailed age-related observed and expected mortality rates for Cerebral Palsy patients by sex and a severity factor that divides the patients into two groups of approximately equal size. The factor used was quadriplegia (all four limbs involved in motor dysfunction). Spasticity was the predominant feature of the motor dysfunction. CONCLUSION: Excess mortality was moderate in the less severe Cerebral Palsy patients, but was higher in those with quadriplegia (overall EDR--Excess Death Rate--about 6 per 1000 and 16 per 1000, respectively). In less severe cases EDR was higher at ages 1-4 years, the almost constant to age 49, then rose with advancing age. In case with quadriplegia EDR decreased in childhood and young adults to a relatively stable minimum at ages 25-49, then increased at older ages. There was little sex difference in EDR.

Activities of Daily Living↗
PubMed1998

Using Kleisli to Bring Out Features in BLASTP Results.

BLASTP gives a good overall indication of what function a protein might have. However, analysis of BLASTP reports to discover various domain features in the protein is still tedious. We address this problem by using the modern data integration system, Kleisli, to bring out annotated features of BLASTP results. We further strengthen our solution by incorporating additional information from SEG, ClustalW, hmmPfam, etc. It is also noteworthy that the codes of our implementation is sufficiently short to be presented in its entirety.

Journal Article↗
PubMed1998

Life expectancy of adults with cerebral palsy.

To determine the predictors of mortality and find the life expectancies of adults with cerebral palsy (CP), data on 24,768 individuals aged 15 years and over who received services in California between January 1980 and December 1995 were analyzed. Multivariate statistical methods to identify mortality predictors, and actuarial methods to determine corresponding life expectancies were used. The key predictors were lack of basic functional skills: mobility and feeding. Adults lacking these skills had much reduced life expectancies, as short as 11 years for the worst functioning groups. By contrast, survival of high-functioning adults was close to that of the general population. The influence on survival of cognitive skills, type of CP, and other factors appears to be expressed largely through their effect on basic functioning. Life expectancies of adults of a given age can differ by 40 years or more, according to their functional level.

Activities of Daily Living↗
PubMed1997

Adenovirus E1a interferes with expression of vaccinia viral genes.

The 12S and 13S cDNAs of the oncogene E1a encoded by the early region of adenovirus 12 (Ad12) were overexpressed using the T7/encephalomyocarditis (EMC)/vaccinia hybrid expression system. The E1a proteins were stable for at least 12 h in monkey epithelial BSC1 cells. The E1a proteins were recognized by a rabbit polyclonal antibody and displayed phosphorylation patterns similar to those displayed by the E1a proteins expressed in Ad12-transformed cells. Expression of E1a proteins by recombinant vaccinia virus led to inhibition of vaccinia viral protein synthesis which was observed as soon as 6 h after infection. This suppression was mediated by both the 12S and the 13S products of Ad12E1a and to a somewhat lesser extent by the 13S product of Ad2E1a. The inhibition of vaccinia virus gene expression resulted in enhanced survival of vaccinia virus-infected cells. These results suggest that the proteins encoded by the E1a sequester a viral or a cellular product(s) that is essential for the expression of vaccinia virus-encoded genes.

Adenoviridae↗
PubMed1997

Characterization of glutamine synthetase transcript, protein, and enzyme activity in the human placenta.

This study characterizes the molecular mechanisms necessary for glutamine synthesis in the human placenta. RNA hybridization and protein immunoblotting were used to verify the presence of glutamine synthetase (GS) transcripts and protein, respectively. Additionally, the presence of GS was determined by immunohistochemistry. RNA hybridization demonstrated the presence of 1.8- and 2.8-kB transcripts and protein immunoblotting yielded a single 49-kDa band, characteristics of GS transcripts and protein, respectively. The mean (+/- s.d.) specific activity of placental GS, expressed as mumol gamma-glutamyl hydroxamic acid/mg protein/h was 1.80 +/- 0.59, which is comparable to other organs which are net glutamine producers. Immunohistochemical analysis indicated the presence of GS within the cytotrophoblast and mesenchyme layers of placental villi, but not in the syncytiotrophoblast. Although these results suggest that the human placenta is capable of synthesizing glutamine, the fate of glutamine produced by this organ remains speculative.

Female↗
PubMed1997

Tubefeeding and mortality in children with severe disabilities and mental retardation.

OBJECTIVE: To study the contribution of tubefeeding to mortality for children with severe disabilities and mental retardation. Previous research has suggested an association between tubefeeding and mortality. However, risk has never been determined using population-based data or defined in regard to patient variables. METHODS: Retrospective analysis of a comprehensive statewide data set comprised of 4921 children with severe disabilities and mental retardation living in community and congregate care settings. The outcome measure was mortality; primary study variables included the presence of a feeding tube, measures of functional independence, type of residence, and medical comorbidity. RESULTS: There were four findings. First, the use of a feeding tube was associated with virtually every disability. Second, when no study variables were controlled, statistically significant differences in mortality rates were noted between children who were tubefed and those who were not. The relative risk of mortality associated with use of a feeding tube was 2.1. Third, the use of a feeding tube was associated with a reduction in relative risk of mortality in children with tracheostomy (relative risk of mortality: .55). However, this association did not achieve statistical significance. Fourth, when study variables were controlled in a multivariate analysis, feeding tube use was associated with no identifiable increase in mortality among children with very severe disabilities, but was associated with an approximated doubled mortality rate among those with less severe disabilities. CONCLUSIONS: We hypothesize that the increased mortality associated with tubefeeding may be attributable to a differential increase in pulmonary disease secondary to overly vigorous nutritional maintenance and subsequent aspiration after tube placement. For children with tracheostomy this risk may be reduced. If tracheostomy proves to be associated with a relatively more favorable outcome for tubefeeding, we hypothesize that it would reflect the benefits of tracheostomy in allowing access to the airway for suctioning and ventilation. Given the observed higher mortality rates among the less severely disabled children who are tubefed and the substantial costs associated with tubefeeding, a prospective, controlled study may be clinically indicated, ethically justifiable, and economically warranted.

Adolescent↗
PubMed1997

Comparative mortality in mentally retarded patients in California, with and without Down's syndrome, 1986-1991.

BACKGROUND: The large database of the California Department of Developmental Services provides a data source for mortality rates in persons with mental retardation by age, sex, severity, cause and associated conditions. RESULTS: Data for 1986-1991 were used to determine age-related mortality rates in cases with and without Down's Syndrome, in three severity levels of mental retardation. Distribution data for the data-base population are also given. CONCLUSION: In both Down's and non-Down's patient groups excess mortality increased with severity of mental retardation at all ages. In both groups excess mortality tended to decrease with advancing age to age 35-39 years, and to increase at the older ages. The age increase in excess death rate at age 40 years and up was steeper in the patients with Down's Syndrome.

Adolescent↗
PubMed1997

Prognosis for survival and improvement in function in children with severe developmental disabilities.

OBJECTIVE: To derive prognostic data for survival and clinical improvement in children with severe developmental disabilities. STUDY DESIGN: A 13-year follow-up study of several cohorts of children initially evaluated before their first birthday. The outcomes studied were survival and improvement in condition. Methods were used to overcome limitations in previously published work on the same California data base. Of the 11,912 children who received services from the California Department of Developmental Services between January 1980 and December 1993, we focused on three cohorts defined according to mobility and need for tube feeding. RESULTS: Children who were tube fed and unable to lift their heads by ages 3 to 12 months were at high risk for early death, with a median remaining life expectancy of 3.2 years. Of those who survived an additional 2 years, the condition of about one third improved. A substantial majority of those who either showed improvement or died had done so by that age. CONCLUSION: By age 5 years, the prognoses for survival and improvement have to a large extent been clarified. For children who survive to age 5 years, even those in the lowest functioning cohort have a 60% chance of surviving an additional 5 years. Detailing the probabilities of various outcomes at various ages should be useful to parents, pediatricians, and others concerned with children with developmental disabilities.

Age Distribution↗