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Biomedical subjects

M D Schwartz

Publications and source records attributed to M D Schwartz.

At least 19 recordsLinked to original sources
PubMed2005

Individual differences in rhythms of behavioral sleep and its neural substrates in Nile grass rats.

Laboratory populations of grass rats (Arvicanthis niloticus) housed with a running wheel show considerable variation in patterns of locomotor activity. At the extremes are "day-active" (DA) animals with a monophasic distribution of running throughout the light phase and "night-active" (NA) animals exhibiting a biphasic pattern with an extended peak at the beginning of the dark phase and a brief peak shortly before lights-on. Here, the authors use this intraspecific variation to explore interactions between circadian and homeostatic influences on sleep and the effects of these interactions on the activity of brain regions involved in sleep regulation. Male animals were singly housed with running wheels in a 12:12 LD cycle, videotaped for 24 h, and perfused at ZT 4 or 16. Behavioral sleep was scored from the videotapes, and brains were processed for cFos immunoreactivity (cFos-ir). Sleep duration within the light and dark phases was higher in NA and DA animals, respectively, but these groups did not differ with respect to total sleep. In both groups, sleep bouts were shortest in the light phase and longest between ZT 20 and ZT 23. In the ventrolateral preoptic area (VLPO), cFos-ir was higher at ZT 16 than at ZT 4 in DA but not NA grass rats, and it was correlated with behavioral sleep at ZT 16 but not ZT 4. In OXA neurons, cFos-ir was high at ZT 4 in DA grass rats and at ZT 16 in NA grass rats, and it was correlated with behavioral sleep at both times. In the lower subparaventricular zone (LSPV), cFos-ir was higher at ZT 16 in both DA and NA animals, and it was unrelated to behavioral sleep. Thus, patterns of cFos-ir in the LSPV and OXA neurons were most tightly linked to time and sleep, respectively, whereas cFos-ir in the VLPO was influenced by an interaction between these 2 variables.

Animals↗
PubMed2004

Differences in the suprachiasmatic nucleus and lower subparaventricular zone of diurnal and nocturnal rodents.

Diurnal and nocturnal species are profoundly different in terms of the temporal organization of daily rhythms in physiology and behavior. The neural bases for these divergent patterns are at present unknown. Here we examine functional differences in the suprachiasmatic nucleus (SCN) and one of its primary targets in a diurnal rodent, the unstriped Nile grass rat (Arvicanthis niloticus) and in a nocturnal one, the laboratory rat (Rattus norvegicus). Grass rats and laboratory rats were housed in a 12:12 light:dark cycle, and killed at six time points. cFos-immunoreactive rhythms in the SCN of grass rats and laboratory rats were similar to those reported previously, with peaks early in the light phase and troughs in the dark phase. However, cFos-immunoreactivity in the lower subparaventricular zone (LSPV) of grass rats rose sharply 5 h into the dark phase, and remained high through the first hour after light onset, whereas in laboratory rats it peaked 1 h after light onset and was low at all other sampling times. Daily cFos rhythms in both the SCN and the LSPV persisted in grass rats, but not in laboratory rats, after extended periods in constant darkness. In grass rats, the endogenous cFos rhythm in the LSPV, but not the SCN, was present both in calbindin-positive and in calbindin-negative cells. Cells that expressed cFos at night in the region of the LSPV in grass rats were clearly outside of the boundaries of the SCN as delineated by Nissl stain and immunoreactivity for vasopressin and vasoactive intestinal peptide. The LSPV of the grass rat, a region that receives substantial input from the SCN, displays a daily rhythm in cFos expression that differs from that of laboratory rats with respect to its rising phase, the duration of the peak and its dependence on a light/dark cycle. These characteristics may reflect the existence of mechanisms in the LSPV that enable it to modulate efferent SCN signals differently in diurnal and nocturnal species.

Animals↗
PubMed2001

Impact of educational print materials on knowledge, attitudes, and interest in BRCA1/BRCA2: testing among Ashkenazi Jewish women.

BACKGROUND: The recent identification of several BRCA1/BRCA2 founder mutations among Ashkenazi Jewish individuals has led to increased salience of BRCA1/BRCA2 testing for Jewish individuals. Little is known about interest in BRCA1/BRCA2 testing among Ashkenazi Jews from the general population. Furthermore, previous research has not generally evaluated the impact of education on interest in testing among individuals from the general population. The goal of the current study was to examine whether a brief educational booklet regarding BRCA1/BRCA2 testing would influence knowledge, attitudes, and interest in testing among Ashkenazi Jewish women from the general population. METHODS: After a baseline telephone interview, participants were randomized to receive either genetic testing educational print materials (n = 195 women) or general breast cancer education control materials (n = 196 women). One month after receiving these materials, the authors reassessed knowledge, attitudes, and interest in BRCA1/BRCA2 gene testing. RESULTS: Relative to the breast cancer education control materials, the genetic testing education materials led to increased knowledge, increased perception of the risks and limitations of testing, and decreased interest in obtaining a BRCA1/BRCA2 mutation test. CONCLUSIONS: These data indicate that preliminary print education can be used to educate low-risk individuals about BRCA1/BRCA2 genetic testing. This approach may be used to educate low-risk individuals about the benefits and risks/limitations of BRCA1/BRCA2 testing, so that they can make informed decisions about whether to pursue genetic counseling.

BRCA2 Protein↗
PubMed2001

Consent to the use of stored DNA for genetics research: a survey of attitudes in the Jewish population.

The use of anonymized stored tissue is a routine practice in genetic research. Investigators who utilize stored samples are neither required nor able to obtain informed consent before each use. Many genetic studies, however, are conducted on specific ethnic populations (e.g., Ashkenazi Jews). The results in these cases, although individually anonymous, are not anonymous with respect to the ethnicity of the participants. This lack of group anonymity has led to concern about the possibility of stigmatization and discrimination based on the results of the genetic research. In the present study we surveyed Jewish individuals about their attitudes regarding the practice of using stored DNA samples for genetic research. Specifically, we were interested in whether attitudes about informed consent and willingness to participate in genetics research using stored DNA would depend on the circumstances in which the material was collected (i.e., clinical setting vs. research setting) and the characteristics of the disease or trait under investigation. Overall, most respondents reported that written informed consent should be required and that they would be willing to provide such consent. Participants were most willing to provide consent, however, when the sample had been collected in a research rather than clinical setting. Further, participants were more likely to endorse the need for obtaining consent when the sample was collected in a clinical setting. Finally, participants were significantly less willing to participate in research that examined stereotypical or potentially stigmatizing traits as opposed to research that examined medical or mental illnesses.

Adolescent↗
PubMed2001

Flock house virus RNA replicates on outer mitochondrial membranes in Drosophila cells.

The identification and characterization of host cell membranes essential for positive-strand RNA virus replication should provide insight into the mechanisms of viral replication and potentially identify novel targets for broadly effective antiviral agents. The alphanodavirus flock house virus (FHV) is a positive-strand RNA virus with one of the smallest known genomes among animal RNA viruses, and it can replicate in insect, plant, mammalian, and yeast cells. To investigate the localization of FHV RNA replication, we generated polyclonal antisera against protein A, the FHV RNA-dependent RNA polymerase, which is the sole viral protein required for FHV RNA replication. We detected protein A within 4 h after infection of Drosophila DL-1 cells and, by differential and isopycnic gradient centrifugation, found that protein A was tightly membrane associated, similar to integral membrane replicase proteins from other positive-strand RNA viruses. Confocal immunofluorescence microscopy and virus-specific, actinomycin D-resistant bromo-UTP incorporation identified mitochondria as the intracellular site of protein A localization and viral RNA synthesis. Selective membrane permeabilization and immunoelectron microscopy further localized protein A to outer mitochondrial membranes. Electron microscopy revealed 40- to 60-nm membrane-bound spherical structures in the mitochondrial intermembrane space of FHV-infected cells, similar in ultrastructural appearance to tombusvirus- and togavirus-induced membrane structures. We concluded that FHV RNA replication occurs on outer mitochondrial membranes and shares fundamental biochemical and ultrastructural features with RNA replication of positive-strand RNA viruses from other families.

Animals↗
PubMed2001

Effects of coping style and BRCA1 and BRCA2 test results on anxiety among women participating in genetic counseling and testing for breast and ovarian cancer risk.

Using the monitoring process model (MPM), the authors examined the immediate effects of coping style and test results on the psychological distress of women at increased risk for breast and/or ovarian cancers. Cases selected for analysis were 107 probands and relatives of positive probands participating in genetic counseling and testing for heritable cancer risk. Specifically, the authors explored the relationships among coping style (high and low monitoring), test results (BRCA1 and BRCA2 mutation carrier and noncarrier status), and psychological distress (state anxiety). Consistent with the MPM, higher monitoring was associated with greater psychological distress while anticipating genetic test results. After test results were disclosed, greater distress was associated with testing positive for a mutation. The implications of the findings for breast and ovarian cancer patients are discussed.

Adaptation, Psychological↗
PubMed2000

Determining the growing season of land vegetation on the basis of plant phenology and satellite data in Northern China.

The objectives of this study are to explore the relationships between plant phenology and satellite-sensor-derived measures of greenness, and to advance a new procedure for determining the growing season of land vegetation at the regional scale. Three phenological stations were selected as sample sites to represent different climatic zones and vegetation types in northern China. The mixed data set consists of occurrence dates of all observed phenophases for 50-70 kinds of trees and shrubs from 1983 to 1988. Using these data, we calculated the cumulative frequency of phenophases in every 5-day period (pentad) throughout each year, and also drew the cumulative frequency distribution curve for all station-years, in order to reveal the typical seasonal characteristics of these plant communities. The growing season was set as the time interval between 5% and 95% of the phenological cumulative frequency. Average lengths of the growing season varied between 188 days in the northern, to 259 days in the southern part of the research region. The beginning and end dates of the surface growing season were then applied each year as time thresholds, to determine the corresponding 10-day peak greenness values from normalized difference vegetation index curves for 8-km2 pixels overlying the phenological stations. Our results show that, at the beginning of the growing season, the largest average greenness value occurs in the southern part, then in the northern, and finally the middle part of the research region. In contrast, at the end of the growing season, the largest average greenness value is measured in the northern part, next in the middle and lastly the southern part of the research region. In future studies, these derived NDVI thresholds can be applied to determine the growing season of similar plant communities at other sites, which lack surface phenological data.

China↗
PubMed2000

Managed care, time pressure, and physician job satisfaction: results from the physician worklife study.

OBJECTIVE: To assess the association between HMO practice, time pressure, and physician job satisfaction. DESIGN: National random stratified sample of 5,704 primary care and specialty physicians in the United States. Surveys contained 150 items reflecting 10 facets (components) of satisfaction in addition to global satisfaction with current job, one's career and one's specialty. Linear regression-modeled satisfaction (on 1-5 scale) as a function of specialty, practice setting (solo, small group, large group, academic, or HMO), gender, ethnicity, full-time versus part-time status, and time pressure during office visits. "HMO physicians" (9% of total) were those in group or staff model HMOs with > 50% of patients capitated or in managed care. RESULTS: Of the 2,326 respondents, 735 (32%) were female, 607 (26%) were minority (adjusted response rate 52%). HMO physicians reported significantly higher satisfaction with autonomy and administrative issues when compared with other practice types (moderate to large effect sizes). However, physicians in many other practice settings averaged higher satisfaction than HMO physicians with resources and relationships with staff and community (small to moderate effect sizes). Small and large group practice and academic physicians had higher global job satisfaction scores than HMO physicians (P <.05), and private practice physicians had quarter to half the odds of HMO physicians of intending to leave their current practice within 2 years (P <.05). Time pressure detracted from satisfaction in 7 of 10 satisfaction facets (P <.05) and from job, career, and specialty satisfaction (P <.01). Time allotted for new patients in HMOs (31 min) was less than that allotted in solo (39 min) and academic practices (44 min), while 83% of family physicians in HMOs felt they needed more time than allotted for new patients versus 54% of family physicians in small group practices (P <.05 after Bonferroni's correction). CONCLUSIONS: HMO physicians are generally less satisfied with their jobs and more likely to intend to leave their practices than physicians in many other practice settings. Our data suggest that HMO physicians' satisfaction with staff, community, resources, and the duration of new patient visits should be assessed and optimized. Whether providing more time for patient encounters would improve job satisfaction in HMOs or other practice settings remains to be determined.

Adult↗
PubMed2000

NF-kappaB regulatory mechanisms in alveolar macrophages from patients with acute respiratory distress syndrome.

Activation of the nuclear regulatory factor NF-kappaB occurs in the lungs of patients with the acute respiratory distress syndrome (ARDS) and may contribute to the increased expression of immunoregulatory cytokines and other proinflammatory mediators in this setting. Because of the important role that NF-kappaB activation appears to play in the development of acute lung injury, we examined cytoplasmic and nuclear NF-kapppaB counterregulatory mechanisms, involving IkappaB proteins, in alveolar macrophages obtained from 7 control patients without lung injury and 11 patients with established ARDS. Cytoplasmic levels of the NF-kappaB subunits p50, p65, and c-Rel were significantly decreased in alveolar macrophages from patients with ARDS, consistent with enhanced migration of liberated NF-kappaB dimers from the cytoplasm to the nucleus. Cytoplasmic and nuclear levels of IkappaBalpha were not significantly altered in alveolar macrophages from patients with established ARDS, compared with controls. In contrast, nuclear levels of Bcl-3 were significantly decreased in patients with ARDS compared with controls (P = 0.02). No IkappaBgamma, IkappaBbeta, or p105 proteins were detected in the cytoplasm of alveolar macrophages from control patients or patients with ARDS. The presence of activated NF-kappaB in alveolar macrophages from patients with established ARDS implies the presence of an ongoing stimulus for NF-kappaB activation. In this setting, appropriate counterregulatory mechanisms to normalize nuclear levels of NF-kappaB and to suppress NF-kappaB-mediated transcription, such as increased cytoplasmic and nuclear IkappaBalpha levels or decreased Bcl-3 levels, appeared to be induced. Nevertheless, even though counterregulatory mechanisms to NF-kappaB activation are activated in lung macrophages of patients with ARDS, NF-kappaB remains activated. These results suggest that fundamental abnormalities in transcriptional mechanisms involving NF-kappaB and important in the inflammatory response occur in the lungs of patients with ARDS.

B-Cell Lymphoma 3 Protein↗
PubMed2000

Spiritual faith and genetic testing decisions among high-risk breast cancer probands.

Despite widespread access to genetic testing for the BRCA1 and BRCA2 breast cancer susceptibility genes, little is known about rates or predictors of test use among individuals from newly ascertained high-risk families who have self-referred for genetic counseling/testing. The objective of this study was to examine rates of test use within this population. In addition, we sought to determine whether spiritual faith and psychological factors influenced testing decisions. Participants were 290 women with familial breast cancer. All were offered genetic counseling and testing for alterations in the BRCA1 and BRCA2 genes. Baseline levels of spiritual faith, cancer-specific distress, perceived risk, and demographic factors were examined to identify independent predictors of whether participants received versus declined testing. The final logistic model revealed statistically significant main effects for spiritual faith [odds ratio (OR), 0.2; 95% confidence intervals (CIs), 0.1 and 0.5] and perceived ovarian cancer risk (OR, 2.4; 95% CIs, 1.3 and 4.7) and a statistically significant spiritual faith by perceived risk interaction effect. Among women who perceived themselves to be at low risk of developing breast cancer again, those with higher levels of spiritual faith were significantly less likely to be tested, compared with those with lower levels of faith (OR, 0.2; 95% CIs, 0.1 and 0.5). However, among women with high levels of perceived risk, rates of test use were high, regardless of levels of spiritual faith (OR, 1.2; 95% CIs, 0.4 and 3.0). These results highlight the role that spirituality may play in the decision-making process about genetic testing.

Adult↗
PubMed1999

Distress, personality, and mammography utilization among women with a family history of breast cancer.

The authors examined the impact of psychological distress and the personality construct of conscientiousness (as measured by the Neuroticism, Extraversion, and Openness-Five Factor Inventory) on mammography utilization among women who were at increased risk for breast cancer. Participants were 200 women who had at least 1 first degree relative with breast cancer. Overall, 80% of the participants had obtained a mammogram in the previous year. Analyses controlling for potential confounders (perceived risk, decisional balance, and physician recommendation for mammography), revealed that distress was negatively associated with mammography utilization among participants who were low in conscientiousness. Distress was not significantly related to mammography utilization among highly conscientious women. The results are discussed in terms of their implications regarding interventions designed to increase mammography utilization in this population.

Adult↗
PubMed1999

Refining the measurement of physician job satisfaction: results from the Physician Worklife Survey. SGIM Career Satisfaction Study Group. Society of General Internal Medicine.

BACKGROUND: Physician job satisfaction has been linked to various patient care and health system outcomes. A survey instrument that concisely measures physicians' satisfaction with various job facets can help diverse stake-holders to better understand and manage these outcomes. OBJECTIVE: To document the development and validation of a multidimensional physician job satisfaction measure and separate global satisfaction measures. DESIGN: Self-administered questionnaire: Physician Worklife Survey (PWS). SUBJECTS: A pilot study employed a national American Medical Association Masterfile sample of US primary care physicians and random samples from four states. Responses (n = 835; 55% return rate) were randomly assigned to developmental (n = 560) or cross-validation (n = 275) samples. A national sample (n = 2,325; 52% response rate) of physicians was used in a subsequent validation study. RESULTS: A 38-item, 10-facet satisfaction measure resulting from factor and reliability analyses of 70 pilot items was further reduced to 36 items. Reliabilities of the 10 facets ranged from .65 to .77. Three scales measuring global job, career, and specialty satisfaction were also constructed with reliabilities from .84 to .88. Results supported face, content, convergent, and discriminant validity of the measures. CONCLUSIONS: Physician job satisfaction is a complex phenomenon that can be measured using the PWS.

Adult↗
PubMed1999

Measuring physician job satisfaction in a changing workplace and a challenging environment. SGIM Career Satisfaction Study Group. Society of General Internal Medicine.

BACKGROUND: Changes in the demographic, specialty, and employment sector composition of medicine have altered physicians' jobs, limiting autonomy and reducing morale. Because physician job satisfaction has been linked to clinical variables, better measurement might help to ameliorate conditions linked to medical disaffection, possibly improving health care. OBJECTIVE: To document conceptual development, item construction, and use of content experts in designing multidimensional measures of physician job satisfaction and global satisfaction scales for assessing physicians' job perceptions across settings and specialties. DESIGN: Using previous research, physician focus groups, secondary analysis of survey data, interviews with physician informants, and a multispecialty physician expert panel, distinct job facets and statements representing those facets were developed. RESULTS: Facets from previously validated instruments included autonomy, relationships with colleagues, relationships with patients, relationships with staff, pay, resources, and status. New facets included intrinsic satisfaction, free time away from work, administrative support, and community involvement. Physician status items were reconfigured into relationships with peers, patients, staff, and community, yielding 10 hypothetical facets. Global scales and items were developed representing satisfaction with job, career, and specialty. CONCLUSIONS: A comprehensive approach to assessing physician job satisfaction yielded 10 facets, some of which had not been previously identified, and generated a matching pool of items for subsequent use in field tests.

Attitude of Health Personnel↗
PubMed1999

A randomized trial of breast cancer risk counseling: the impact on self-reported mammography use.

OBJECTIVES: We evaluated the impact of individualized breast cancer risk counseling on mammography use among women at risk for breast cancer. METHODS: Participants (n = 508) were randomized to the breast cancer risk counseling intervention or a general health education control intervention, and 85% completed follow-up. RESULTS: In multivariate modeling, a significant group-by-education interaction demonstrated that among less-educated participants, breast cancer risk counseling led to reduced mammography use. There was no intervention effect among the more-educated participants. CONCLUSIONS: These results suggest that standard breast cancer risk counseling could have an adverse impact on the health behaviors of less-educated women.

Adult↗
PubMed1998

The impact of a brief problem-solving training intervention for relatives of recently diagnosed breast cancer patients.

Previous studies have found high levels of psychological distress in women who have a family history of breast cancer. We evaluated a brief Problem-Solving Training (PST) intervention designed to reduce distress among women with a first-degree relative recently diagnosed with this disease. Participants were randomly assigned to either the PST group (N = 144) or a General Health Counseling (GHC) control group (N = 197). At baseline, these groups did not differ on any sociodemographic, risk factor, or psychological distress variables. We evaluated the impact of PST, relative to GHC, at the three-month follow-up assessment using a 2 (treatment group) x 2 (time of assessment) mixed factor analysis of variance (ANOVA). Although there were significant decreases in both cancer-specific and general distress in both the PST and GHC groups, the magnitude of these decreases did not differ. However, when PST participants were divided into those who regularly practiced the PST techniques and those who did not, significant differences emerged. Participants who regularly practiced the PST techniques had significantly greater decreases in cancer-specific distress [Impact of Event Scale (IEs) intrusion and avoidance subscales] compared to infrequent practicers and GHC participants. Effects on general distress were not found. Additional studies are needed to identify ways to promote the practice of PST techniques and to evaluate other psychosocial interventions for female relatives of breast cancer patients.

Adaptation, Psychological↗
PubMed1998

Ambulatory versus inpatient rotations in teaching third-year students internal medicine.

We studied 63 randomly selected third-year students who split their 10-week medicine clerkship between ambulatory and inpatient components. Compared with their inpatient experience, during the ambulatory rotation, the 63 students felt more like doctors, more responsible for patients, and more able to know and help their patients. Students reported that ambulatory attending staff appeared happier and less stressed, and did not embarrass them as frequently. Compared with their 619 "inpatient" classmates, these 63 "ambulatory" students scored as well on the medicine examination, and were as likely to receive honors (44% vs 41%), and to choose internal medicine residencies (35% vs 34%). In conclusion, students experienced better relationships with their patients and teachers during the ambulatory rotation, which was academically comparable to the inpatient experience.

Adult↗