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Biomedical subjects

R Friedman

Publications and source records attributed to R Friedman.

At least 37 records · Page 2Linked to original sources
PubMed2000

WebDietAID: an interactive Web-based nutritional counselor.

WebDietAID is a Web-based system aimed at assisting individuals affected by high serum cholesterol. The system tries to reproduce the types of intervention performed by a nutritional counselor. It is structured as a set of advisors, each of which handles a different side of the counseling process. The tasks of the advisors range from monitoring weight, to teaching about healthy nutrition, to assessing motivation and psychological obstacles to behavior change. WebDietAID is based on a development environment for Web-based applications that includes a dynamical Web server, a knowledge base management system, and an interface to a relational database. We describe the architecture of the system, and several of the implemented advisors. Finally, we discuss how the architecture could be generalized to other counseling domains.

Computer-Assisted Instruction↗
PubMed1999

Maternally inherited hearing loss in a large kindred with a novel T7511C mutation in the mitochondrial DNA tRNA(Ser(UCN)) gene.

Thirty-six of 43 maternally related members of a large African American family experienced hearing loss. A muscle biopsy specimen from the proband showed cytochrome c oxidase (COX)-deficient fibers but no ragged-red fibers; biochemical analysis showed marked reduction of COX activity. A novel T7511C point mutation in the tRNA(Ser(UCN)) gene was present in almost homoplasmic levels (>95%) in the blood of 18 of 20 family members, and was also found in lower abundance in the other two. Single-fiber PCR showed that the mutational load was greater in COX-deficient muscle fibers. The tRNA(ser(UCN)) gene may be a "hot spot" for mutations associated with maternally transmitted hearing loss.

Adult↗
PubMed1999

Classical conditioning of the human blood pressure response.

The object of this experiment was to demonstrate that blood pressure responses could be classically conditioned in human subjects and to describe the topography of the conditioned response. Despite clear evidence for classical blood pressure conditioning in animals there is little evidence concerning a clear demonstration of the phenomenon in human subjects, and no description of the form of the conditioned response. A 'neutral' 8-s 70-db tone (CS) was paired with a 500-ms electric shock (UCS) in a delay conditioning paradigm. Conditioned subjects were compared to a control group that received the CS and UCS on a truly random schedule. The subjects in the conditioning group showed a conditioned blood pressure response that emerged during the last 4 s of the 8-s CS. The results differ from those obtained from animals, where the CR typically emerges during the first half of the CS. These data may have implications for the role of learning in hypertensive disorders.

Acoustic Stimulation↗
PubMed1999

An automated telephone system for monitoring the functional status of community-residing elders.

We tested the reliability and validity of an automated telephone monitoring system for assessing changes in the functional status of disabled elders living in the community. The sample consisted of 20 adults older than 60 years of age enrolled in a home care program due to functional disabilities. Within a 72-hour period, each participant received, in random order, two automated and one personal telephone functional assessment as well as a home visit assessment by a case manager. The results indicated similarities between the personal and automated telephone assessments, but neither telephone method captured as many impairments as the case manager's home assessment. These findings suggest that the automated system cannot substitute for a case manager's in-home assessment, but it does offer a means to target individuals for additional professional assessment.

Activities of Daily Living↗
PubMed1999

Intravascular extraction of problematic or infected permanent pacemaker leads: 1994-1996. U.S. Extraction Database, MED Institute.

Of the 400,000-500,000 permanent pacemaker leads implanted worldwide each year, around 10% may eventually fail or become infected, becoming potential candidates for removal. Intravascular techniques for removing problematic or infected leads evolved over a 5-year period (1989-1993). This article analyzes results from January 1994 through April 1996, a period during which techniques were fairly stable. Extraction of 3,540 leads from 2,338 patients was attempted at 226 centers. Indications were: infection (27%), nonfunctional or incompatible leads (25%), Accufix or Encore leads (46%), or other causes (2%). Patients were 64+/-17 years of age (range 5-96); 59% were men, 41% women. Leads were implanted 47+/-41 months (maximum 26 years), in the atrium (53%), ventricle (46%), or SVC (1%). Extraction was attempted via the implant vein using locking stylets and dilator sheaths, and/or transfemorally using snares, retrieval baskets, and sheaths. Complete removal was achieved for 93% of leads, partial for 5%, and 2% were not removed. Risk of incomplete or failed extraction increased with implant duration (P<0.0001), less experienced physicians (P<0.0001), ventricular leads (P<0.005), noninfected patients (P<0.0005), and younger patients (P<0.0001). Major complications were reported for 1.4% of patients (<1% at centers with >300 cases), minor for 1.7%. Risk of complications increased with number of leads removed (P<0.005) and with less experienced physicians (P<0.005); risk of major complications was higher for women (P<0.01). Given physician experience, appropriate precautions, and appropriate patient selection, contemporary lead removal techniques allow success with low complication rates.

Adolescent↗
PubMed1999

Distress and conception in infertile women: a complementary approach.

OBJECTIVES: To examine the relationship of pretreatment psychological distress and demographics to conception in infertile women attending a group cognitive-behavioral treatment program. METHODS: Pre- and postprogram psychological measures and live birth rates were collected for 132 infertile women attending a ten-session group cognitive-behavioral treatment program. Subjects completed the Beck Depression Inventory (BDI) and the Symptom Checklist-90 (Revised) (SCL-90R). Conceptions that resulted in live births within six months of completing the program were noted. RESULTS: Women who conceived viable pregnancies within six months of the program had higher levels of psychological distress at program entry. Using logistic regression analysis, the best predictors of viable birth were younger age and a higher score on the global severity index of the SCL-90R. Significant pre- to postprogram psychological improvement was demonstrated by the SCL-90R and the BDI. Forty-two percent of the sample conceived viable pregnancies within six months of completing the program. CONCLUSIONS: Preprogram psychological distress and younger age were associated with significantly higher viable pregnancy rates.

Adult↗
PubMed1998

Effects of therapy with nifedipine GITS or atenolol on mental stress-induced ischemic left ventricular dysfunction.

OBJECTIVES: We sought to determine the effect of nifedipine gastrointestinal therapeutic system (GITS) or atenolol on ischemic left ventricular dysfunction induced by mental stress. BACKGROUND: The efficacy of conventional antianginal therapy in preventing myocardial ischemia induced by mental stress is unknown. METHODS: Nifedipine GITS, atenolol and placebo were administered to 15 subjects with stable angina in a double-blind crossover trial. Subjects underwent a series of mental stressors at the end of each treatment. Radionuclide ventriculography was performed at baseline and at peak mental stress. Other measured variables included time to ischemia on exercise treadmill testing, ischemia on 48-h ambulatory electrocardiogram (ECG) monitoring, and resting and mental stress-induced levels of plasma catecholamines, tissue plasminogen activator antigen, plasminogen activator inhibitor-1 and platelet aggregability. RESULTS: Mental stress resulted in a significant increase in plasma epinephrine and norepinephrine levels during each treatment phase. Atenolol therapy was associated with lower baseline and postmental stress rate-pressure product compared with nifedipine or placebo. Therapy with either nifedipine GITS or atenolol prevented the development of wall-motion abnormalities and the decline in regional ejection fraction (EF) in the segment with the largest deterioration in wall motion during placebo therapy. Both medications prevented the decrease in global EF in subjects who demonstrated at least a 5% fall in global EF on placebo therapy. No therapy exerted a statistically significant benefit on exercise performance or frequency of ischemia during ambulatory ECG monitoring. CONCLUSIONS: Both nifedipine GITS and atenolol are effective at preventing mental stress-induced wall-motion abnormalities, although the mechanisms may be different.

Adrenergic beta-Antagonists↗
PubMed1998

Comparison of long-term care in an acute care institution and in a long-term care institution.

BACKGROUND: Acute care hospitals in Quebec are required to reserve 10% of their beds for patients receiving long-term care while awaiting transfer to a long-term care facility. It is widely believed that this is inefficient because it is more costly to provide long-term care in an acute care hospital than in one dedicated to long-term care. The purpose of this study was to compare the quality and cost of long-term care in an acute care hospital and in a long-term care facility. METHODS: A concurrent cross-sectional study was conducted of 101 patients at the acute care hospital and 102 patients at the long-term care hospital. The 2 groups were closely matched in terms of age, sex, nursing care requirements and major diagnoses. Several indicators were used to assess the quality of care: the number of medical specialist consultations, drugs, biochemical tests and radiographic examinations; the number of adverse events (reportable incidents, nosocomial infections and pressure ulcers); and anthropometric and biochemical indicators of nutritional status. Costs were determined for nursing personnel, drugs and biochemical tests. A longitudinal study was conducted of 45 patients who had been receiving long-term care at the acute care hospital for at least 5 months and were then transferred to the long-term care facility where they remained for at least 6 months. For each patient, the number of adverse events, the number of medical specialist consultations and the changes in activities of daily living status were assessed at the 2 institutions. RESULTS: In the concurrent study, no differences in the number of adverse events were observed; however, patients at the acute care hospital received more drugs (5.9 v. 4.7 for each patient, p < 0.01) and underwent more tests (299 v. 79 laboratory units/year for each patient, p < 0.001) and radiographic examinations (64 v. 46 per 1000 patient-weeks, p < 0.05). At both institutions, 36% of the patients showed anthropometric and biochemical evidence of protein-calorie undernutrition; 28% at the acute care hospital and 27% at the long-term care hospital had low serum iron and low transferrin saturation, compatible with iron deficiency. The longitudinal study showed that there were more consultations (61 v. 37 per 1000 patient-weeks, p < 0.02) and fewer pressure ulcers (18 v. 34 per 1000 patient-weeks, p < 0.05) at the acute care hospital than at the long-term care facility; other measures did not differ. The cost per patient-year was $7580 higher at the acute care hospital, attributable to the higher cost of drugs ($42), the greater use of laboratory tests ($189) and, primarily, the higher cost of nursing ($7349). For patients requiring 3.00 nursing hours/day, the acute care hospital provided more hours than the long-term care facility (3.59 v. 3.03 hours), with a higher percentage of hours from professional nurses rather than auxiliary nurses or nursing aides (62% v. 28%). The nurse staffing pattern at the acute care hospital was characteristic of university-affiliated acute care hospitals. INTERPRETATION: The long-term care provided in the acute care hospital involved a more interventionist medical approach and greater use of professional nurses (at a significantly higher cost) but without any overall difference in the quality of care.

Aged↗
PubMed1998

Accuracy of conversion formulae for estimation of glycohaemoglobin.

To analyse the accuracy of the conversion formulae for estimation of glycohaemoglobin (GHb) measured by different methods, we analysed 210 samples for HbA1c using HPLC. Fifty of these specimens were analysed by micro-column chromatography (MC), 43 by electrophoresis (EP), 50 by IMX system (Abbott Laboratories), 38 by Primus HPLC and 29 by Diamat HPLC. Regression analyses were performed and the equations were used to estimate HbA1c values (HbA1c calc) for the five methods. The 95% limits of agreement between HPLC and the converted results were -1.77 to 1.71%, -1.54 to 1.54%, -0.92 to 0.88%, -0.46 to 0.56%, and -0.39 to 0.41% for MC, EP, IMX, Primus and Diamat equations, respectively. The mean relative errors were 3.4 (-28.2 to 35%), 1.3 (-22.9 to 25.5%), 0.4 (-14.6 to 15.0%), 0.51 (-6.55 to 7.57%), -0.20 (-5.8 to 5.4%), for MC, EP, IMX, Primus and Diamat, respectively. These results show that conversion formulae based on methods that do not measure HbA1c (MC, EP and IMX) are inaccurate and can mask a clinically relevant variation of HbA1c. However, GHb results obtained by HPLC methods could be interchangeably converted with an absolute variation of less than 1%. Converted HbA1c results from non-standardized methods should be interpreted with caution.

Chromatography, Affinity↗
PubMed1998

Profiling outcomes of ambulatory care: casemix affects perceived performance.

OBJECTIVES: The authors explored the role of casemix adjustment when profiling outcomes of ambulatory care. METHODS: The authors reviewed the medical records of 656 patients with hypertension, diabetes, or chronic obstructive pulmonary disease (COPD) receiving care at one of three Department of Veterans Affairs medical centers. Outcomes included measures of physiological control for hypertension and diabetes, and of exacerbations for COPD. Predictors of poor outcomes, including physical examination findings, symptoms, and comorbidities, were identified and entered into regression models. Observed minus expected performance was described for each site, both before and after casemix adjustment. RESULTS: Risk-adjustment models were developed that were clinically plausible and had good performance properties. Differences existed among the three sites in the severity of the patients being cared for. For example, the percentage of patients expected to have poor blood pressure control were 35% at site 1, 37% at site 2, and 44% at site 3 (P < 0.01). Casemix-adjusted measures of performance were different from unadjusted measures. Sites that were outliers (P < 0.05) with one approach had observed performance no different from expected with another approach. CONCLUSIONS: Casemix adjustment models can be developed for outpatient medical conditions. Sites differ in the severity of patients they treat, and adjusting for these differences can alter judgments of site performance. Casemix adjustment is necessary when profiling outpatient medical conditions.

Aged↗
PubMed1998

Problems in assessing diabetes control in an ambulatory setting.

Problems in using medical records to assess outcomes of diabetes care have not been well defined. We reviewed the medical records of 288 patients with diabetes receiving ambulatory care over a 2-year period. We determined the availability of different tests of glycemic control and described site performance as the percentage of patients with a blood glucose exceeding either 180 or 240 mg/dl. Glycosylated hemoglobin determinations were performed in only 26.7% of patients. A blood glucose was available in 208 patients (72.2%) during a 6-month outcome period. For almost 50% of the sample, the glucose was greater than 180 mg/dl, whereas in 20% it exceeded 240 mg/dl. Judgments of whether sites differed in performance depended on how control was defined. Using a single glucose determination and a threshold of 180 mg/dl, similar fractions of patients were poorly controlled at each site (51.2 versus 45.0 versus 47.0%) (P = 0.75). At 240 mg/dl, although, one site performed much worse than the other two (14.6 versus 16.7 versus 31.8%) (P = 0.02). These results highlight difficulties in defining the outcome measure when using medical records to evaluate quality of care.

Aged↗
PubMed1997

Continuous infusion of prostacyclin normalizes plasma markers of endothelial cell injury and platelet aggregation in primary pulmonary hypertension.

BACKGROUND: Primary pulmonary hypertension (PPH) is characterized by vascular injury of pulmonary arterioles, in which endothelial dysfunction may play a major role. Although continuous infusion of prostacyclin (prostaglandin I2, a potent vasodilator released by vascular endothelial cells) improves the clinical status and survival in PPH, its mechanism or mechanisms of action remain unclear. METHODS AND RESULTS: We measured endothelium-derived clotting factors and assayed platelet aggregation in 64 patients (26 adults and 38 children) with PPH before long-term PGI2 therapy. Repeat studies were performed in 42 patients (18 adults, 24 children) after one year of PGI2 therapy. At baseline, 87% of adults and 79% of children had abnormal platelet aggregation. In addition, factor VIII, von Willebrand (vW) antigen, and ristocetin cofactor levels were abnormally high in 92%, 72%, and 52%, respectively, of the adults versus 29%, 16%, and 16%, respectively, of the children (P<.005 adults versus children). With long-term PGI2, platelet aggregation normalized in 83% of the adults and 80% of the children who had platelet aggregation abnormalities at baseline (P<.01). Factor VIII, vW antigen, and ristocetin cofactor also decreased with long-term PGI2 in both groups (P<.02). The ratio of ristocetin cofactor to vW antigen, which may reflect biological activity of vW factor, increased with long-term PGI2 in adults from an abnormally low level (0.6+/-0.2) to normal level (1.10+/-0.4), and in children the ratio increased from 0.8+/-0.3 to 1.3+/-0.4 (normal, 0.8 to 1.4). CONCLUSIONS: Alterations in the coagulation system may contribute to the pathogenesis of PPH; the normalization of these endothelial markers concomitant with improvement in hemodynamic parameters with long-term PGI2 suggests that long-term PGI2 remodels the pulmonary vascular bed with subsequent decreases in endothelial cell injury and hypercoagulability.

Adolescent↗
PubMed1997

Glucocorticoid repression of gonadotropin-releasing hormone gene expression and secretion in morphologically distinct subpopulations of GT1-7 cells.

Two morphologically distinct subpopulations of GT1-7 cells have been characterized and examined for their responsiveness to glucocorticoids. Type I cells have a neuronal phenotype, extending many lengthy processes, and express neuronal, but not glial, markers. Type II cells show weaker or negative immunostaining for neuronal markers and exhibit fewer processes. The effect of glucocorticoids on gonadotropin-releasing hormone (GnRH) secretion and gene expression was compared in type I and type II GT1-7 cells. For secretion studies, cells were attached to Cytodex beads and perifused with control medium or medium containing dexamethasone (dex). The high level of GnRH secreted by type I cells was slightly enhanced in the presence of dex, whereas dex rapidly and profoundly decreased the already low level of GnRH secreted by type II cells. Immunocytochemistry for GnRH showed dark reaction product in the cell bodies and processes of type I cells and little or no immunoreactivity in type II cells. Both the endogenous mouse GnRH mRNA and the transcriptional activity of a mouse GnRH promoter luciferase reporter gene plasmid were suppressed to a greater extent in type II cells than in type I. In electrophoretic mobility shift assays, there was no difference between type I and type II nuclear extracts in the pattern of protein-DNA complexes formed on two previously identified negative glucocorticoid response elements located at -237 to -201 and -184 to -150 bp of the mouse promoter. Both cell types contained glucocorticoid receptors (GR) by Western blot analysis. Cytosols from type I or type II cells were incubated with [3H]dex to obtain GR binding parameters. Binding data were consistent with a one-site model for dex binding in each case. Small differences in Kd (1.7 nM, type I; 3.1 nM, type II) or Bmax (approximately 3600 sites/cell, type I; approximately 1800 sites/cell, type II) were not likely to account for the differential sensitivity to dex treatment. In conclusion, nuclear alterations in type II cells leading to greater transcriptional susceptibility to dex, coupled with low GnRH storage levels, may be reflected in exquisite sensitivity of GnRH secretion to glucocorticoid repression. This represents the first example of a steroid hormone acting directly on GnRH-producing cells to alter GnRH secretion.

Animals↗
PubMed1997

Additional antianginal and anti-ischemic efficacy of mibefradil in patients pretreated with a beta blocker for chronic stable angina pectoris.

This study assessed the safety, tolerability, and efficacy of mibefradil when added to beta-blocker monotherapy in patients with chronic stable angina pectoris. Two hundred five patients were randomized to receive double-blind treatment with either placebo (n = 70), mibefradil 25 mg (n = 67), or mibefradil 50 mg (n = 68) for 2 weeks. Exercise tolerance tests (ETTs) were performed at the end of the run-in (baseline) and double-blind treatment periods, and patients maintained an anginal diary. Compared with placebo, treatment with mibefradil 50 mg resulted in significant increases in exercise duration (36 +/- 51 seconds; p = 0.036), time to onset of angina (48 +/- 65 seconds; p = 0.002), and time to persistent 1-mm ST-segment depression (47 +/- 77 seconds; p = 0.004). Greater reductions in heart rate, blood pressure, and the rate-pressure product were more apparent at each stage of the ETT in the 50-mg mibefradil group than in the placebo group. Daily treatment with mibefradil 50 mg was associated with a significant decrease in the number of weekly anginal attacks (-2.1 +/- 4.0, p = 0.020) compared with placebo. The addition of mibefradil to existing beta-blocker therapy was well tolerated. Dizziness was the most frequently reported adverse event in the mibefradil 50-mg dose, and occurred with an incidence of 4.4%. The addition of mibefradil 50 mg, administered once daily, to patients on stable beta-blocker therapy produced additive antianginal and anti-ischemic effects and was well tolerated.

Adrenergic beta-Antagonists↗