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S Kaplan

Publications and source records attributed to S Kaplan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Reliability of multicenter pediatric echocardiographic measurements of left ventricular structure and function: the prospective P(2)C(2) HIV study.

BACKGROUND: To assess the reliability of pediatric echocardiographic measurements, we compared local measurements with those made at a central facility. METHODS AND RESULTS: The comparison was based on the first echocardiographic recording obtained on 735 children of HIV-infected mothers at 10 clinical sites focusing on measurements of left ventricular (LV) dimension, wall thicknesses, and fractional shortening. The recordings were measured locally and then remeasured at a central facility. The highest agreement expressed as an intraclass correlation coefficient (ICC=0.97) was noted for LV dimension, with much lower agreement for posterior wall thickness (ICC=0.65), fractional shortening (ICC=0.64), and septal wall thickness (ICC=0.50). The mean dimension was 0.03 cm smaller in central measurements (95% prediction interval [PI], -0.32 to 0.25 cm) for which 95% PI reflects the magnitude of differences between local and central measurements. Mean posterior wall thickness was 0.02 cm larger in central measurements (95% PI, -0.18 to 0.22 cm). Mean fractional shortening was 1% smaller in central measurements. However, the 95% PI was -10% to 8%, indicating that a fractional shortening of 32% measured centrally could be anywhere between 22% and 40% when measured locally. Central measurements of mean septal thickness were approximately 0.1 cm thicker than local ones (95% PI, -0.18 to 0.34 cm). Centrally measured wall thickness was more closely related to mortality and possibly was more valid than local measurements. CONCLUSIONS: Although LV dimension was reliably measured, local measurements of LV wall thickness and fractional shortening differed from central measurements.

Cardiac Volume↗
PubMed2001

Relation between paroxysmal atrial fibrillation and left ventricular diastolic function in patients with acute myocardial infarction.

The relation between left ventricular filling pattern and the occurrence of paroxysmal atrial fibrillation was evaluated using Doppler echocardiography in a prospective series of 157 patients with acute myocardial infarction. Paroxysmal atrial fibrillation after acute myocardial infarction was often associated with a higher restrictive filling pattern.

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PubMed2001

A 3'-transcribed region of the HLA-A2 gene mediates posttranscriptional stimulation by IFN-gamma.

The expression of several MHC class I genes is up-regulated at the transcriptional level by IFN-gamma. Posttranscriptional mechanisms also have been implicated, but not well characterized. To investigate the mechanism of IFN-gamma stimulation of the human MHC class I gene HLA-A2, several human tumor cell lines were transfected with reporter gene constructs driven by the HLA-A2 promoter. We have previously shown that the extended 525-bp HLA-A2 promoter alone, which includes a 5' IFN-stimulated response element consensus sequence, is not sufficient for IFN-gamma response in either K562 or Jurkat cells. In the current study, stable transfection of a genomic HLA-A2 gene construct, containing both 5'- and 3'-flanking sequences, resulted in stimulation of the gene by IFN-gamma. Nuclear run-on assays revealed that, unlike other class I genes, IFN-gamma stimulation of HLA-A mRNA accumulation occurs almost entirely through posttranscriptional mechanisms. RNA stability assays showed that the effect is not mediated by alteration of the half-life of the HLA-A2 mRNA. Formation of the 3' end was unaffected by IFN-gamma treatment. Sequences that mediate the majority of IFN-gamma induction of HLA-A2 mRNA reside in a 127-bp 3'-transcribed region of the gene. This region contains the terminal splice site, the usage of which is not affected by IFN-gamma treatment. These results demonstrate a novel posttranscriptional mechanism of regulation of MHC class I genes by IFN-gamma.

3' Untranslated Regions↗
PubMed2001

Patients' role in the use of radiology testing for common office practice complaints.

BACKGROUND: Radiological studies are an important component of ambulatory medical costs, and guidelines often focus on their appropriate use. However, little is known about the correlates of the use of those services, particularly the influence of patients' preferences on physicians' utilization decisions. OBJECTIVES: To study patients presenting for outpatient treatment of respiratory problems and low back pain, and to examine the magnitude of the effect of the patients' perceived need for radiological studies (radiology preference score) on use of those services. DESIGN: Cross-sectional survey. SETTING: Office practices of generalist physicians in predominantly rural areas of 8 states. PARTICIPANTS: A total of 52 generalist physicians agreed to enroll consecutive Medicare-eligible patients making office visits for respiratory problems or low back pain. Of 1785 eligible patients invited to participate, 132 (7%) refused and 1137 (69%) of 1653 returned questionnaires. MEASUREMENTS: Radiology utilization rates (plain film, computed tomographic scan, or magnetic resonance image scan) were determined by patient self-report. To assess perceived need for radiological studies, we asked patients how necessary they believed an x-ray film was in the evaluation of 4 common complaints (respiratory problems, low back pain, knee pain, and knee swelling). A summary radiology preference score was created from 3 of the 4 items, excluding the item referring to the patients' index complaint. RESULTS: Six hundred fifteen respiratory and 522 low back pain patients were enrolled; mean ages were 69 and 64 years, respectively. Radiology utilization rates were 37% for respiratory and 26% for low back pain patients. In multiple logistic regression models, for respiratory patients radiology utilization was related significantly to the radiology preference score (odds ratio [OR] for fourth quartile compared with first quartile, 1.94; 95% confidence interval [CI], 1.11-3.37; P = .02), to having a physician who owned radiology equipment (OR, 1.81; 95% CI, 1.23-2.66; P = .002), and current smoking (OR, 1.58; 95% CI, 1.04-2.41; P = .03). For low back pain patients, radiology utilization was significantly related to the radiology preference score (OR for fourth compared with first quartile, 2.55; 95% CI, 1.29-5.06; P = .007), bothersomeness of the pain (OR for fourth compared with first quartile, 3.74; 95% CI, 1.74-8.04; P<.001), and a diagnosis of osteoporosis (OR, 1.67; 95% CI, 1.01-2.75; P = .04). CONCLUSIONS: Patients' perceived need for radiological studies was significantly associated with use of those services for outpatients with respiratory problems and low back pain. These findings suggest that patients communicate their wishes to physicians, either directly or indirectly, regarding services they think are necessary. Differences in physicians' adherence to guidelines regarding radiology utilization may in part reflect variations in patients' perceived need for those services. Efforts to educate patients about when radiological studies are medically indicated may be an important complement to practice guidelines or other utilization-related financial incentives.

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PubMed2001

Coping with change: the small experiment as a strategic approach to environmental sustainability.

The patterns of living, planning, and resource utilization as practiced in Western countries for decades are not sustainable; change of some sort is essential. But what changes are appropriate, and, perhaps more important, will people accept them? The small experiment framework provides a strategy for meeting the challenge of change. By encouraging participation, limiting the scale of initial change, and incorporating some aspects of the familiar, many of the difficulties that make change so problematic can be mitigated or even eliminated. An exploration, from a psychological perspective, of the characteristic difficulties surrounding potential change provides the context for a discussion of the components of the small experiment and an analysis of how these elements address these characteristic challenges. A comparison to adaptive management is drawn, and several concrete examples illustrate how the strategy has been used successfully to address a variety of environmental problems.

Adaptation, Psychological↗
PubMed2001

Child abuse in Turkey: an experience in overcoming denial and a description of 50 cases.

OBJECTIVE: To share the experiences of the first clinical multidisciplinary child abuse and neglect (CAN) team in Turkey with international child abuse community. METHODS: The authors established the first Turkish CAN follow-up team at Dr. Behcet Uz Children's Hospital. Following a training program in five teaching hospitals in Izmir, the authors kept a record of every case diagnosed with CAN from these hospitals between 1996 and 1998. The demographic, epidemiologic, and medical features of this case series are summarized. RESULTS: Fifty cases were diagnosed and followed-up. Seventy-six percent of patients were reported from Dr. Behcet Uz Children's Hospital. Age and sex distribution was 9.2 +/- 6.7 years and 46% male, 54% female, respectively. The offenders were only father in 38%, only mother in 28%, and multiple in 34%. More than three CAN risk factors were present in 94%. Of the children reported 44% survived, 14% died, and 42% were lost to follow-up. Sixteen percent were free of reabuse, and 42% survived with handicaps. CONCLUSIONS: Child abuse and neglect is a reality in Turkey. The team's work increased pediatricians' awareness of CAN. Reporting these cases to Social Affairs Bureau was established for the first time in Turkey. Physicians in Turkey need training to diagnose and properly report CAN. The implemen tation of a national CAN prevention program is an urgent need for Turkey.

Adolescent↗
PubMed2001

Patent ductus arteriozus associated with anomalous origin of the right coronary artery: a case report.

Patent ductus arteriozus (PDA) is the most common type of extracardiac shunt and it usually closes within 2 or 3 days of birth, but it may remain patent for one's lifetime. In this paper, we report a 65-year-old woman with PDA associated with a right coronary arising anomaly. To our knowledge, the anomalous origin of the right coronary artery associated with PDA has not been published to date. In this case report, we used only the standard Judkins type of a left coronary catheter for cannulation of both left and right coronary arteries and as well as PDA.

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PubMed2001

The home stretch, a first analysis of the nearly completed genome of Rhodobacter sphaeroides 2.4.1.

Rhodobacter sphaeroides 2.4.1 is an alpha-3 purple nonsulfur eubacterium with an extensive metabolic repertoire. Under anaerobic conditions, it is able to grow by photosynthesis, respiration and fermentation. Photosynthesis may be photoheterotrophic using organic compounds as both a carbon and a reducing source, or photoautotrophic using carbon dioxide as the sole carbon source and hydrogen as the source of reducing power. In addition, R. sphaeroides can grow both chemoheterotrophically and chemoautotrophically. The structural components of this metabolically diverse organism and their modes of integrated regulation are encoded by a genome of approximately 4.5 Mb in size. The genome comprises two chromosomes CI and CII (2.9 and 0.9 Mb, respectively) and five other replicons. Sequencing of the genome has been carried out by two groups, the Joint Genome Institute, which carried out shotgun-sequencing of the entire genome and The University of Texas-Houston Medical School, which carried out a targeted sequencing strategy of CII. Here we describe our current understanding of the genome when data from both of these groups are combined. Previous work had suggested that the two chromosomes are equal partners sharing responsibilities for fundamental cellular processes. This view has been reinforced by our preliminary analysis of the virtually completed genome sequence. We also have some evidence to suggest that two of the plasmids, pRS241a and pRS241b encode chromosomal type functions and their role may be more than that of accessory elements, perhaps representing replicons in a transition state.

Journal Article↗
PubMed2001

Introduction.

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Journal Article↗
PubMed2001

A simple technique to measure the movements of the microscope stage along the x and y axes for stereological methods.

Measurements of microscope stage movements in the x and y directions are of importance for some stereological methods such as the optical disector and optical fractionator. The length of stage movements can be measured with great precision and accuracy using a suitable motorized stage, which is generally a computer-assisted instrument. This type of equipment is generally too expensive for and not readily available in many laboratories. This paper describes a simple method to measure the movements of the microscope stage along the x and y directions, which can be used for purposes such as systematic uniform random sampling. It needs a microscope attachment consisting of two dial indicators; one of them is used to measure the amount of stage movement along the x-axis and the other measures the amount of movement along the y-axis. Movements of the stage on the micrometre-scale can be measured easily using this device.

Journal Article↗
PubMed2001

Dilation of the aortic root in children infected with human immunodeficiency virus type 1: The Prospective P2C2 HIV Multicenter Study.

BACKGROUND: Vascular lesions have become more evident in human immunodeficiency virus type 1 (HIV)-infected patients as the result of earlier diagnosis, improved treatment, and longer survival. Aortic root dilation in HIV-infected children has not previously been described. This study was undertaken to determine the prevalence of aortic root dilation in HIV-infected children and to evaluate some of the potential pathogenic mechanisms. METHODS: Aortic root measurements were incorporated into the routine echocardiographic surveillance of 280 children of HIV-infected women: an older cohort of 86 HIV-infected children and a neonatal cohort of 50 HIV-infected and 144 HIV-uninfected children. RESULTS: By repeated-measures analyses, mean aortic root measurements were significantly increased in HIV-infected children versus HIV-uninfected children (P values of < or =.04 and < or =.005 at 2 and 5 years of age, respectively, for aortic annulus diameter, sinuses of Valsalva, and sinotubular junction). Heart rate, systolic blood pressure, stroke volume, hemoglobin, and hematocrit were not significantly associated with aortic root size. Left ventricular dilation, increased serum HIV RNA levels, and lower CD4 cell count measurements were associated with aortic root dilation at baseline. CONCLUSIONS: Mild and nonprogressive aortic root dilation was seen in children with vertically transmitted HIV infection from 2 to 9 years of age. Aortic root size was not significantly associated with markers for stress-modulated growth; however, aortic root dilation was associated with left ventricular dilation, increased viral load, and lower CD4 cell count in HIV-infected children. As prolonged survival of HIV-infected patients becomes more prevalent, some patients may require long-term follow-up of aortic root size.

Aorta↗
PubMed2001

Fitting hierarchical holographic modeling into the theory of scenario structuring and a resulting refinement to the quantitative definition of risk.

A point of view is suggested from which the Hierarchical Holographic Modeling (HHM) method can be seen as one more method within the Theory of Scenario Structuring (TSS), which is that part of Quantitative Risk Assessment having to do with the task of identifying the set of risk scenarios. Seen in this way, HHM brings strongly to our attention the fact that different methods within TSS can result in different sets of risk scenarios for the same underlying problem. Although this is not a problem practically, it is a bit awkward conceptually from the standpoint of the "set of triplets" definition of risk, in which the scenario set is part of the definition. Accordingly, the present article suggests a refinement to the set of triplets definition, which removes the specific set of scenarios, found by any of the TSS methods, from the definition of risk and casts it, instead, as an approximation to the "true" set of scenarios that is native to the problem at hand and not affected by the TSS method used.

Journal Article↗
PubMed2001

Generalized approach to the regulation and integration of gene expression.

The volume of electron flow through the cbb3 branch of the electron transport chain and the redox state of the quinone pool generate signals that regulate photosynthesis gene expression in Rhodobacter sphaeroides. An inhibitory signal is generated at the level of the catalytic subunit of the cbb3 cytochrome c oxidase and is transduced through the membrane-localized PrrC polypeptide to the PrrBA two-component activation system, which controls the expression of most of the photosynthesis genes in response to O2. The redox state of the quinone pool is monitored by the redox-active AppA antirepressor protein, which determines the functional state of the PpsR repressor protein. The antirepressor/repressor system as well as a modulator of AppA function, TspO, together with FnrL and PrrA stringently control photopigment gene expression. These regulatory elements, together with spectral complex-specific assembly factors, control the ultimate cellular levels and composition of the photosynthetic membrane.

Bacterial Proteins↗
PubMed2001

TspO as a modulator of the repressor/antirepressor (PpsR/AppA) regulatory system in Rhodobacter sphaeroides 2.4.1.

The TspO outer membrane protein of Rhodobacter sphaeroides has been shown to be involved in controlling the transcription of a number of genes which encode enzymes involved in photopigment biosynthesis and the puc operon. The display of regulated genes appears identical to those genes encompassing the PpsR/AppA repressor/antirepressor regulon, although the effect of TspO is modest relative to that of PpsR/AppA. To directly address the hypothesis that TspO is effective through the PpsR/AppA system, we constructed mutant strains with mutations in both tspO and appA. In all cases, the phenotypes examined resembled those of the appA lesion by itself, leading us to conclude that TspO works through or modulates the PpsR/AppA system and acts upstream of the site of action of these regulatory proteins. In earlier publications, we had suggested that TspO is involved in the efflux of a certain intermediate(s) of the porphyrin biosynthesis pathway and that transcriptional regulation of target gene expression could be explained by the accumulation of a coactivator of AppA function. Although the data reported here do not precisely identify this coactivator, they lend support to this hypothesis. We discuss the importance of this form of gene control as the result of the recent extension of the TspO system to Sinorhizobium meliloti, as described by Davey and de Bruijn (M. E. Davey and F. J. de Bruijn, Appl. Environ. Microbiol. 66:5353-5359, 2000). It is therefore possible that this system constitutes a more widely, although not universally, demonstrated form of gene regulation.

Bacterial Proteins↗
PubMed2001

The default state of the membrane-localized histidine kinase PrrB of Rhodobacter sphaeroides 2.4.1 is in the kinase-positive mode.

The PrrBA two-component activation system of Rhodobacter sphaeroides plays a major role in the induction of photosynthesis gene expression under oxygen-limiting or anaerobic conditions. The PrrB histidine kinase is composed of two structurally identifiable regions, the conserved C-terminal kinase/phosphatase domain and the N-terminal membrane-spanning domain with six transmembrane helices framing three periplasmic and two cytoplasmic loops. Using a set of PrrB mutants with lesions in the transmembrane domain, we demonstrate that the central portion of the PrrB transmembrane domain including the second periplasmic loop plays an important role in both sensing and signal transduction. Signal transduction via the transmembrane domain is ultimately manifested by controlling the activity of the C-terminal kinase/phosphatase domain. The extent of signal transduction is determined by the ability of the transmembrane domain to sense the strength of the inhibitory signal received from the cbb(3) terminal oxidase (J.-I Oh, and S. Kaplan, EMBO J. 19:4237-4247, 2000). Therefore, the intrinsic ("default") state of PrrB is in the kinase-dominant mode. It is also demonstrated that the extent of prrB gene expression is subject to the negative autoregulation of the PrrBA system.

Amino Acid Sequence↗
PubMed2001

Consumer satisfaction at a child and adolescent state psychiatric hospital.

OBJECTIVE: This study examined satisfaction with services among patients in a child psychiatric hospital and their parents, and assessed the relationship between consumer satisfaction and the perception of improvement in the problem that led to hospitalization. METHODS: A consumer satisfaction survey developed by the investigators was administered to three sampling waves of child and adolescent psychiatric inpatients (N=157) and their parents or guardians (N=111). Ninety-five percent of patients contacted and 97 percent of their parents or guardians agreed to participate in the study. The survey provided data about the children's and parents' satisfaction with inpatient care and their perceptions of the children's clinical improvement. RESULTS: Most parents and children reported high satisfaction with patient care. Twenty-eight percent of children and 21 percent of parents reported some form of abuse by the staff during the hospital stay. Those who reported abusive behavior were significantly less satisfied with the hospital experience than those who did not report abuse. The participants' perception of clinical improvement was only weakly related to their satisfaction. CONCLUSIONS: Most child psychiatric patients and their parents will participate in consumer satisfaction surveys about inpatient care. Consumers are critical of a hospital if specific prompts in the survey are provided. An unexpectedly high level of consumer-reported abuse was found. Consumer-perceived clinical improvement was only weakly related to satisfaction.

Adolescent↗
PubMed2001

Serum lipoprotein(a) and its relation to left ventricular thrombus in patients with acute myocardial infarction.

It is well known that the incidence of left ventricular (LV) thrombosis is high in patients with acute myocardial infarction (AMI). Due to the high degree of structural homology with plasminogen, lipoprotein(a) may produce thrombogenic effects by modulating the fibrinolytic system. However, the role of Lp(a) level in the formation of LV thrombus has not been studied. This study sought to determine whether Lp(a) is a risk factor for LV thrombus in patients with AMI. We have analyzed clinical, echocardiographic and biochemical data in 102 consecutive patients (aged 58+/-12 years, 92 men / 10 women) with first anterior AMI. Two-dimensional examination was performed on days 1, 3, 7, 15, and 30. Blood samples were obtained within 12 h after the onset of symptoms and before beginning the therapy. Plasma levels of fibrinogen and Lp(a) were measured using enzyme-linked immunosorbent assay and immunonephelometric methods, respectively. LV thrombus was detected in 20 (20.3%) patients. No significant difference was found for admission Lp(a) levels between patients with or without thrombus (30.5+/-17.2 vs 32.3+/-22.4 mg/dl, p = 0.7). Univariate analysis showed that patients with LV thrombus had a higher wall motion score index (1.8+/-0.3 vs 1.4+/-0.3, p = 0.002), a higher peak creatine kinase level (2945+/-898 vs 1805+/-1336, I / U p = 0.004), a larger end-diastolic volume (139.7+/-38.6 vs 114.1+/-41.8 ml, p = 0.04), a larger end-systolic volume (83.1+/-34.3 vs 59.2+/-30.6 ml, p = 0.02 ), and a lower ejection fraction (38+/-12 vs 47+/-11, p = 0.04). In multivariate analyses, only peak creatine kinase level (p = 0.04) and LV wall motion score index (p = 0.002) were independent predictors of left ventricular thrombus formation. These results suggest that Lp (a) is not a risk factor for LV thrombus in patients with AMI. Our data demonstrate that the best predictors of LV thrombus formation after AMI are a high peak creatine kinase level and a high LV wall motion score index.

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