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Biomedical subjects

R Goldberg

Publications and source records attributed to R Goldberg.

At least 55 records · Page 3Linked to original sources
PubMed1999

Heating of cardiovascular stents in intense radiofrequency magnetic fields.

We consider the heating of a metal stent in an alternating magnetic field from an induction heating furnace. An approximate theoretical analysis is conducted to estimate the magnetic field strength needed to produce substantial temperature increases. Experiments of stent heating in industrial furnaces are reported, which confirm the model. The results show that magnetic fields inside inductance furnaces are capable of significantly heating stents. However, the fields fall off very quickly with distance and in most locations outside the heating coil, field levels are far too small to produce significant heating. The ANSI/IEEE C95.1-1992 limits for human exposure to alternating magnetic fields provide adequate protection against potential excessive heating of the stents.

Blood Vessels↗
PubMed1999

HIV-risk practices among homeless and low-income housed mothers.

BACKGROUND: Knowledge of human immunodeficiency virus (HIV) and its risk behaviors have not been systematically studied in homeless mothers. The identification of the factors associated with HIV-risk practices will guide interventions for low-income housed and homeless women. METHODS: We interviewed 220 homeless and 216 low-income housed mothers living in Worcester, Massachusetts, to gather information on demographic, psychosocial , and HIV-risk practice characteristics. We used standardized instruments and questions drawn from national surveys. The primary study outcome was high HIV-risk behavior. RESULTS: Although homeless mothers were more likely than low-income housed mothers to report first sexual contact at an early age, multiple partners during the last 6 months, and a history of intravenous drug use, homelessness was not associated with high HIV-risk practices. Both homeless and low-income housed mothers demonstrated misconceptions about HIV transmission through casual contact. Among high-risk women, approximately 75% perceived themselves as having low or no risk for contracting HIV. A history of childhood victimization, adult partner violence, or both placed women at a significantly increased likelihood of high HIV-risk practices. African American race, knowledge about HIV, and self-perception of risk were also significantly associated with high-risk practices. CONCLUSIONS: Homeless mothers are a subgroup of poor women at high risk for HIV and should be targeted for preventive interventions. In addition, there are potentially modifiable factors associated with HIV-risk practices in both low-income housed and homeless mothers that should be directly addressed.

Adult↗
PubMed1998

Investigation of the action patterns of pectinmethylesterase isoforms through kinetic analyses and NMR spectroscopy. Implications In cell wall expansion.

Well characterized pectin samples were incubated with cell wall-bound and -solubilized pure isoforms of pectinmethylesterase from mung bean hypocotyls (Vigna radiata). Both enzyme activity and average product structure were determined at intervals along the deesterification pathway at pH 5.6 and 7.6. The latter analyses were performed by 13C NMR spectroscopy, and the degree of esterification was probed by both 13C NMR and potentiometric measurements. A dichotomy was observed in the behavior of the alpha and gamma isoforms when compared with that of the beta isoenzyme. Ideal blockwise deesterification mechanisms reproduced the experimental average structures (methylester distribution) throughout the course of the reaction. In the case of the alpha and gamma isoforms, a single chain mechanism associated with a free carboxyl group at the second nearest neighbor position could be postulated at pH 5.6, whereas some multiple attack character was required to reproduce the data at pH 7.6. Several mechanisms that differed from the preceding ones were compatible with the data for the beta isoform at the two pH values. Both the nature of the polysaccharides produced in these reactions and the role of pectinmethylesterase in the cell wall-stiffening process along the growth gradient are discussed.

Carboxylic Ester Hydrolases↗
PubMed1998

Characterization of the pectin methylesterase-like gene AtPME3: a new member of a gene family comprising at least 12 genes in Arabidopsis thaliana.

Pectin demethylesterification appears to be catalysed by a number of pectin methylesterase (PME) isoenzymes in higher plant species. In order to better define the biological role of these isoenzymes in plant cell growth and differentiation, we undertook molecular studies on the PME-encoding genes in Arabidopsis thaliana. In this paper, we report the characterization of AtPME3, a new PME-related gene of 4kb in length that we have mapped on Chromosome III. AtPME3 encodes a putative mature PME-related isoenzyme of 34kDa with a basic isoelectric point. Since the extent of the gene family encoding PME in higher plant species is still unknown, we resorted to the use of degenerate primers designed from several well-known consensus regions to identify new PME-related genes in the genome of Arabidopsis. Our results, in combination with several known expressed sequences tags (ESTs), indicate that the Arabidopsis genome contains at least 12 PME-related genes. Consequently, a method of systematic gene expression analysis has been applied in order to discern the expression pattern of these 12 genes throughout the plant at the floral stage. Whereas most of these genes appeared to be more or less ubiquitously expressed throughout the plant, several genes are distinguishable by their strikingly specific expression in certain organs. The present data bring a new insight into the role of specific PME-related genes in flower and root development.

Amino Acid Sequence↗
PubMed1998

Full polysomnography in the home.

STUDY OBJECTIVES: To evaluate unattended full polysomnography (PSG) recorded in the home by the DigiTrace Home Sleep System (DHSS) and to assess the ability to acquire, store and analyze polysomnographic data using the DHSS compared to standard paper PSG. DESIGN: Part 1 used a prospective, cross-over design. Part 2 consisted of a prospective concurrent collection of polysomnographic data. SETTING: Sleep Disorders Center in a university medical center. PARTICIPANTS: All adult patients who required standard clinical PSG as part of their clinical evaluation, regardless of suspected diagnosis, except patients requiring video recording for abnormal behaviors. MEASUREMENTS AND RESULTS: The DHSS is a digital recording system with miniature preamplifiers and the capacity to record 18 channels of polysomnographic data, including 4 channels of EEG (C3-A2, C4-A1, C3-O1 and C4-O2), right and left EOG, two channels of chin EMG, ECG naso-oral airflow, respiratory effort (piezo crystal thoracic and abdominal belts and bilateral interacostal EMG), snore microphone, bilateral anterior tibialis EMG, and body-position sensor. In part 1,77 DHSS home recordings were evaluated. No recordings were lost due to equipment failure and each parameter was scorable in greater than 95% of all epochs. Most of the subjective assessments by questionnaire following each study revealed no difference between the two testing situations. However, patients reported more sleep time and a better overall test experience in the lab. Assessments of sleep quality and morning alertness compared to usual were rated higher in the lab. After completing both studies, more patients preferred the lab study (p < .01), mostly because of minor inconveniences and apprehension regarding acquisition of data during the home study. There was no difference in the assessment of which test most accurately represented their sleep. In Part 2, the DHSS recorded concurrently with paper PSG in the laboratory in 16 patients. The results show no significant differences for any parameter and strong positive correlations for all parameters. CONCLUSION: Using the DHSS, unattended full PSG can be performed in the home with reliable and high quality recordings. Full PSG can be extended to a larger patient population, because it is no longer limited by the number of beds, and there is a reduction in cost due to elimination of overnight staff and facility cost.

Adolescent↗
PubMed1998

The Taskforce 2000 survey on medical education in sleep and sleep disorders.

Previous research has shown evidence of a widening gap between scientific research and clinical teaching in sleep and sleep disorders. To address the deficiencies in current medical education in sleep, the Taskforce 2000 was established by the American Sleep Disorders Association. The present study was undertaken to assess the teaching activities, needs and interests of the membership of the two largest professional sleep societies (American Sleep Disorders Association and Sleep Research Society). Survey instruments included a brief, 5-item postcard survey, which was mailed to all members, followed by an in-depth, 34-item questionnaire, which was completed by 158 respondents from the intitial postcard survey (N = 808). Results indicated that the majority of respondents (65.2%) are currently involved in teaching sleep to medical students or postgraduate trainees, although the average amount of teaching time was only 2.1 hours for undergraduate and 4.8 hours for graduate education in sleep. Teaching of sleep laboratory procedures and clinical evaluation of sleep-disordered patients is limited at either an undergraduate or postgraduate level. The major deficiencies noted were the lack of time in the medical curriculum and the need for better resources and teaching facilities. A large majority of respondents indicated their willingness to be involved in sleep education for physicians, and rated this a high priority for the professional organization.

Curriculum↗
PubMed1998

Inhibition of interleukin-1alpha-induced cartilage oligomeric matrix protein degradation in bovine articular cartilage by matrix metalloproteinase inhibitors: potential role for matrix metalloproteinases in the generation of cartilage oligomeric matrix protein fragments in arthritic synovial fluid.

OBJECTIVE: To determine whether matrix metalloproteinases (MMPs) degrade cartilage oligomeric matrix protein (COMP) to produce fragments similar to those found in synovial fluid (SF) from patients with arthritis. METHODS: COMP fragments were generated in vitro by treating (a) bovine articular cartilage with interleukin-1alpha (IL-1alpha), (b) purified bovine COMP with MMPs, and (c) articular cartilage with MMPs. The fragments generated in each case were analyzed by Western blot, using an antibody to the C-terminal heptadecapeptide of COMP. RESULTS: IL-1alpha stimulation of cartilage resulted in a fragmentation of COMP, which was inhibited by MMP inhibitors CGS 27023A and BB-94. Isolated, recombinant MMPs rapidly degraded purified COMP, as well as COMP residing in cartilage. Several COMP fragments produced in vitro had similar electrophoretic mobility to those in SF of patients with arthritis. CONCLUSION: MMPs may contribute to the COMP fragments found in vivo. Quantitation of MMP-specific fragments may be useful in the evaluation of MMP inhibitors in patients with arthritis.

Animals↗
PubMed1998

An efficient procedure for studying pectin structure which combines limited depolymerization and 13C NMR.

A protocol for partial thermally-induced depolymerization of differently methoxylated pectin samples is described. The resulting macromolecules have been fully characterized with various complementary techniques, such as size exclusion chromatography (SEC), potentiometry, viscometry and 13C NMR. Optimum conditions afford samples at 50-80% yield with weight-average molecular weights in the 4 to 20 kDa range. The major fraction of these polysaccharides adopts the random-coil conformation and such samples are suitable for 13C NMR structural studies at room temperature. The methoxyl distributions of two apple pectin samples with a degree of esterification (DE) between 54 and 74% and a citrus pectin (DE, 72%) were shown to be random in nature, whereas that of a lightly methoxylated apple pectin (DE 39%) was partially blockwise. The carbon relaxation parameters of the depolymerized pectins attain asymptotic values for Mw > 4 kDa. The Mw values estimated from intrinsic viscosity data with the Mark-Houwink relationship reported for native pectins are in good agreement with those obtained by either end-group analysis (NMR) or SEC. Thus, all the physicochemical data indicate that the secondary structure of the isolated chains of depolymerized pectin is closely related to that of the parent polymers. Finally, pectinmethylesterase activity towards the depolymerized pectins was similar to that of the untreated samples.

Carbon Isotopes↗
PubMed1998

Critical pathway for the emergency department management of acute asthma: effect on resource utilization.

STUDY OBJECTIVE: To determine the effect of a critical pathway on resource utilization in asthmatic patients. METHODS: The study combined a prospective analysis of 149 patients with asthma treated by a pathway protocol with a retrospective analysis of 97 patients with asthma treated by conventional means. The setting was a community hospital. RESULTS: Among patients treated by protocol, oxygen use declined by 19% (P = .001), handheld nebulizer treatments by 33% (P = .001), saline locks by 15% (P = .011), and intravenous steroid administration by 13% (P = .034). There was an increase in the use of metered-dose inhalers with spacer by 64% (P = .001) and oral steroids by 18% (P = .027). CONCLUSION: A critical pathway, based primarily on national guidelines, can be an effective means of treating asthma patients in terms of resource utilization.

Acute Disease↗
PubMed1998

High-dose busulfan, melphalan and thiotepa followed by autologous peripheral blood stem cell (PBSC) rescue in patients with advanced stage III/IV ovarian cancer.

The purpose of this study was to evaluate the efficacy of high-dose chemotherapy (HDC) with busulfan, melphalan and thiotepa (BUMELTT) followed by autologous PBSC infusion in treating patients with advanced ovarian cancer. Thirty-one patients, 18 with stage III/IIIc and 13 with stage IV ovarian cancer, were treated with BU (12 mg/kg), MEL (100 mg/m2) and TT (500 mg/m2) and autologous PBSC rescue. Fifteen patients were in clinical complete remission (CR) at treatment; 11 had platinum-sensitive disease. Sixteen patients were not in CR; two had platinum-sensitive disease. The probabilities of overall survival (OS), event-free survival (EFS) and relapse (R) for all patients at 18 months were 0.57, 0.30 and 0.63; for patients in CR, the rates were 0.87, 0.44 and 0.49 and for patients not in CR, 0.38, 0.13 and 0.81. Two patients (6.5%) died of treatment-related causes. Among the 13 patients with platinum-sensitive disease, all are still alive, with seven having relapsed 129-1021 days after PBSC infusion. OS, EFS and R were 1.00, 0.52 and 0.48. Of the 18 patients with platinum-resistant disease, four remain alive (two in remission). Six patients did not respond and eight relapsed from days 104-429. The OS, EFS and R were 0.33, 0.11 and 0.78. We conclude that BUMELTT is well tolerated in patients with advanced ovarian cancer and results are equivalent to other published HDC regimens.

Adult↗
PubMed1998

Health characteristics and medical service use patterns of sheltered homeless and low-income housed mothers.

OBJECTIVE: To compare the health characteristics and service utilization patterns of homeless women and low-income housed women who are heads of household. DESIGN: Case-control study. SETTING: Community of Worcester, Massachusetts. PARTICIPANTS: A sample of 220 homeless mothers and 216 low-income housed mothers receiving welfare. MEASUREMENTS AND MAIN RESULTS: Outcome measures included health status, chronic conditions, adverse lifestyle practices, outpatient and emergency department use and hospitalization rates, and use of preventive screening measures. Both homeless mothers and housed mothers demonstrated low levels of physical and role functioning and high levels of bodily pain. Prevalence rates of asthma, anemia, and ulcer disease were high in both groups. More than half of both groups were current smokers. Compared with the housed mothers, homeless mothers reported more HIV risk behaviors. Although 90% of the homeless mothers had been screened for cervical cancer, almost one third had not been screened for tuberculosis. After controlling for potential confounding factors, the homeless mothers, compared with the housed mothers, had more frequent emergency department visits in the past year (adjusted mean, homeless vs housed, 1.41 vs .95, p = .10) and were significantly more likely to be hospitalized in the past year (adjusted odds ratio 2.22; 95% confidence interval 1.13, 4.38). CONCLUSIONS: Both homeless mothers and low-income housed mothers had lower health status, more chronic health problems, and higher smoking rates than the general population. High rates of hospitalization, emergency department visits, and more risk behaviors among homeless mothers suggest that they are at even greater risk of adverse health outcomes. Efforts to address gaps in access to primary care and to integrate psychosocial supports with health care delivery may improve health outcomes for homeless mothers and reduce use of costly medical care services.

Adult↗
PubMed1998

Genetic heterogeneity of Saethre-Chotzen syndrome, due to TWIST and FGFR mutations.

Thirty-two unrelated patients with features of Saethre-Chotzen syndrome, a common autosomal dominant condition of craniosynostosis and limb anomalies, were screened for mutations in TWIST, FGFR2, and FGFR3. Nine novel and three recurrent TWIST mutations were found in 12 families. Seven families were found to have the FGFR3 P250R mutation, and one individual was found to have an FGFR2 VV269-270 deletion. To date, our detection rate for TWIST or FGFR mutations is 68% in our Saethre-Chotzen syndrome patients, including our five patients elsewhere reported with TWIST mutations. More than 35 different TWIST mutations are now known in the literature. The most common phenotypic features, present in more than a third of our patients with TWIST mutations, are coronal synostosis, brachycephaly, low frontal hairline, facial asymmetry, ptosis, hypertelorism, broad great toes, and clinodactyly. Significant intra- and interfamilial phenotypic variability is present for either TWIST mutations or FGFR mutations. The overlap in clinical features and the presence, in the same genes, of mutations for more than one craniosynostotic condition-such as Saethre-Chotzen, Crouzon, and Pfeiffer syndromes-support the hypothesis that TWIST and FGFRs are components of the same molecular pathway involved in the modulation of craniofacial and limb development in humans.

Acrocephalosyndactylia↗
PubMed1998

Oculoplastic experience with the cosmetic use of botulinum A exotoxin.

BACKGROUND: Botulinum toxin is a neuromuscular blocking agent produced by the bacterium Clostridium botulinum. It has been used as a therapeutic agent in ophthalmology for over 18 years. OBJECTIVE: To present the cosmetic use of botulinum toxin in oculoplastic surgery. METHODS: We present our experience with botulinum toxin as a cosmetic agent. RESULTS: Botulinum toxin was successful in treating hyperfunctional lines of the face and neck. CONCLUSIONS: Botulinum toxin is a safe and effective method of treating dynamic lines of the face and neck.

Botulinum Toxins, Type A↗
PubMed1998

Assessment of chest pain onset and out-of-hospital delay using standardized interview questions: the REACT Pilot Study. Rapid Early Action for Coronary Treatment (REACT) Study Group.

OBJECTIVE: To determine the consistency of responses to a standardized 2-part "key" question (Key-Q) about acute symptom onset in patients presenting with chest pain when measured using alternative questions (Qs) about symptom perception and decisions to seek treatment. METHODS: A structured patient interview was performed at 3 university teaching hospitals and 1 community hospital. Convenience samples of adult patients presenting to these EDs with chest pain were asked specific questions related to their symptoms and recognition of illness. Information obtained included the 2-part Key-Q: "What are the symptoms that brought you here today?" and "When did those symptoms start?" The alternative Qs (in order of use) were as follows: Q1 = "When did your very first symptom or sensation begin?"; Q2 = "When did your symptoms lead you to think something was wrong or that you were ill?"; Q3 = "When did your symptoms become serious enough for you to seek medical care?"; and Q4 = "When did you actually call 9-1-1/emergency medical services (EMS) or go to the hospital?" The documented ED arrival time, demographic variables, and whether the patient arrived by ambulance were obtained from the medical record. Patients also were queried regarding potential barriers to seeking medical care and their cardiac risk factors. RESULTS: Of the 135 patients surveyed, 9 were unsure of the date and time of symptom onset. For the 126 patients with analyzable data, the mean (+/- SD) patient age was 62 +/- 16 years, and 59% were male. The general sequence of events reported from acute symptom onset until hospital care was Q1/Key-Q-->Q2-->Q3-->Q4-->ED arrival. The median differences and interquartile ranges (IQRs) in minutes between Q times and the Key-Q response were: Q1 = 0 (0-0); Q2 = 30 (0-210); Q3 = 140 (30-720); Q4 = 265 (90-1,215); and ED arrival = 340 (120-1,230). The interval from the Key-Q response until calling 9-1-1/EMS or going to the hospital was shorter for those who used an ambulance and for those who did not consult a physician first. The interval from the Key-Q response until considering symptoms to be serious was shorter for those with a family history of heart disease, but longer for non-white patients. CONCLUSION: The Key-Q elicited a response recalled near the time of first symptoms and generally before the patient had concluded something was "wrong or that he or she was ill." Measurement of the out-of-hospital delay in chest pain patients using the Key-Q appears promising.

Acute Disease↗
PubMed1998

Determinants of health and service use patterns in homeless and low-income housed children.

OBJECTIVE: Previous studies of homeless children have described more health problems and service use than in housed children, but failed to control for potential confounding factors that may differ between these children. This observational study examines the relationship of homelessness and other determinants to health status and service use patterns in 627 homeless and low-income housed children. METHODS: Case-control study of 293 homeless and 334 low-income housed children aged 3 months to 17 years and their mothers conducted in Worcester, Massachusetts. Information was collected about mothers' housing history, income, education, emotional distress, and victimization history. Standardized instruments were administered to assess children's health. Health service use questions were adapted from national surveys. Main outcome measures included health status, acute illness morbidity, emergency department and outpatient medical visits. Multivariable regression analyses were used to examine the association of family and environmental determinants, including homelessness, with health status and service use outcomes. RESULTS: Mothers of homeless children were more likely to report their children as being in fair or poor health compared with their housed counterparts. Homeless children were reported to experience a higher number of acute illness symptoms, including fever, ear infection, diarrhea, and asthma. Emergency department and outpatient medical visits were higher among the homeless group. After controlling for potential explanatory factors, homeless children remained more likely to experience fair or poor health status (adjusted odds ratio [OR] = 2.83; 95% confidence interval [CI], 1.16, 4.87), and a higher frequency of outpatient (OR = 1.71; 95% CI, 1.18, 2.48) and emergency department visits (OR = 1.21; 95% CI, 0.83, 1.74). Mothers' emotional distress was independently associated with acute illness symptoms and frequent use of outpatient and emergency department settings. CONCLUSIONS: Homelessness is an independent predictor of poor health status and high service use among children. The present findings highlight the importance of preventive interventions and efforts to increase access to primary care among homeless children.

Adolescent↗
PubMed1998

Directly observed therapy in an inner city hospital.

SETTING: A directly observed therapy (DOT) tuberculosis (TB) program in a large urban teaching hospital in the East Harlem section of New York City. OBJECTIVE: In response to an emergent epidemic of TB, the State Department of Health mobilized a coalition of providers outside the public sector to provide DOT and medical care for people with TB, with the goal of treatment until cure. The results of the first 150 patients of one program are reviewed. DESIGN: A multidisciplinary DOT team coordinated treatment at several sites within and without the institution, according to established medical regimens. RESULTS: The program served a hard-to-reach population, 63% human immunodeficiency virus (HIV) positive, 64% substance users, 17% inadequately housed and 15% indigent. In the program's first three years there was 85% overall compliance with DOT visits. Using the completion of therapy index, 66% of patients completed therapy, 13% remained on treatment, 7% transferred to self medication and 1% were lost to follow up. No patient on DOT developed a drug resistant organism. There were no hospital readmissions for TB. CONCLUSION: The experience of this program demonstrates the efficacy of an intensive, personalized DOT program in ensuring treatment until cure.

AIDS-Related Opportunistic Infections↗
PubMed1997

Bayesian analysis for a single 2 x 2 table.

The simple comparison of two binomial populations is frequently of interest in epidemiology when the domains are large. For small domains, however, there are no exact methods except Fisher's exact test. A basic problem, therefore, is to compare two populations by assessing the difference between the proportions of individuals who possess a characteristic in the first and second populations. When there is prior information, we take the proportions to have independent conjugate beta distributions with known parameters, thereby facilitating a Bayesian analysis. We consider Bayesian inference on functions of the proportions, and the three most common scalar measures used in epidemiology and health services research, namely relative risk, odds ratio and attributable risk. We develop the highest density regions (both exact and approximate) for relative risk, odds ratio and attributable risk. In addition, we consider the Bayes factor for testing whether the model with a common proportion holds rather than one with distinct proportions. Using data from the population-based Worcester Heart Attack Study, we apply our methodology to study gender differences in the therapeutic management of patients with acute myocardial infarction (AMI) by selected demographic and clinical characteristics. The Bayes factor, the approximate and exact intervals generally suggest that there are no substantial differences in the pharmacologic management of males and females hospitalized with AMI.

Adult↗