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Biomedical subjects

L Farber

Publications and source records attributed to L Farber.

At least 19 recordsLinked to original sources
PubMed2006

Experimental study of wet granulation in fluidized bed: impact of the binder properties on the granule morphology.

In this work, the effect of the physicochemical properties of aqueous hydroxypropyl-cellulose (HPC) binder solutions and different pharmaceutical excipients (mannitol and anhydrous CaHPO(4)) on the agglomeration kinetics and granule properties were investigated. First, a particle size distribution (PSD) analysis together with a detailed analysis of morphological properties of the excipient particles were performed. Second, the viscosity, density, surface tension and size of the spray droplets of binder solutions with different HPC concentrations were determined and wetting characteristics of the binders on the excipients were measured. Third, several fluid bed wet granulation experiments were conducted for pure excipients and their blends with binder solution of different HPC concentrations in a pilot plant Wurster granulator. The observed granule growth for different binder concentrations was a strong function of the binder concentration and the excipient solubility. For mannitol, a significant "coating" period followed by a slow granule growth was observed for the case with the diluted 5% binder. The "coating" period was significantly shorter for the 10% HPC binder and did not exist for the 15% HPC for which immediate and fast granule growth was observed. For anhydrous CaHPO(4) (trademark A-TAB), no growth was observed for the 10% HPC binder and a long coating period followed by fast granule growth was observed for the 15% HPC. Simple physically based criteria were also evaluated, which employ the morphological properties of excipients (size and surface roughness) together with physical properties of the used binder for prediction of the coating versus agglomeration regime at given flow conditions (collision velocity). As expected, a preferential coalescence and growth of the mannitol granules from the blend of mannitol+A-TAB was observed. Finally, the mechanical and morphological properties of the produced granules were measured and correlated to the HPC concentration of the binder used in the experiments. A clear correlation between the granule porosity (evaluated by X-ray tomography) and the binder concentration was found for the mannitol granules.

Calcium Phosphates↗
PubMed1999

Room-temperature deintercalation and self-extrusion of Ga from Cr2GaN

Bulk samples of the layered ternary nitride Cr2GaN were observed to extrude filaments of pure elemental gallium at room temperature. This self-extrusion phenomenon is best described as a room-temperature deintercalation of gallium from the basal planes of porous Cr2GaN samples. The extruded filaments are single crystals with 2- to 100-micrometer diameters and can be several centimeters long.

Journal Article↗
PubMed1999

Diagnostic errors of primary care screens for depression and panic disorder.

OBJECTIVE: As the health care reimbursement system has changed, brief screens for detecting mental disorders in primary care have been developed. These efforts have faced the formidable task of identifying patients with mental disorders, while at the same time minimizing the number of misclassified cases. Here we consider the balance between sensitivity and positive predictive value. Primary care patients with false positive and false negative results on screens for depression and panic disorder are compared with regard to comorbidity and functional impairment. METHODS: This was a cross-sectional psychometric study. The study sample included 1001 primary care patients from the Department of Internal Medicine at Kaiser Permanente in Oakland, California. The Symptom-Driven Diagnostic System for Primary Care (SDDS-PC) screens and Sheehan Disability Scale were completed by the subjects. The SDDS-PC diagnostic interviews were administered to all subjects. RESULTS: Patients with false positive results on the panic disorder screen did not differ from patients with false negatives results with regard to rates of other psychiatric disorders, functional impairment, or mental health service utilization. In contrast, patients with false negative depression screen results had significantly more psychiatric disorders and functional impairment than those with false positive depression results. CONCLUSIONS: A substantial number of patients with either false positive or false negative screen results met diagnostic criteria for other mental disorders. Given the nominal burden of follow-up assessments for patients with positive screens, these data suggest that erring on the side of sensitivity may have been preferable when algorithms for these screens were selected.

Adolescent↗
PubMed1998

A diagnostic aid for detecting (DSM-IV) mental disorders in primary care.

This study was designed to develop and validate a new computerized version of the Symptom Driven Diagnostic System for Primary Care (SDDS-PC) and examine its feasibility in primary care practice. One thousand and one patients (ages 18-70) coming for routine care to Kaiser-Permanente were screened on a self-administered symptom scale for major depression, alcohol and drug dependence, generalized anxiety, panic and obsessive compulsive disorders, and suicidal behavior. The screen was followed up by a brief diagnostic interview, administered by a nurse, which yielded a one-page summary of positive symptoms and a provisional computer-generated diagnosis for the physician. The physician reviewed the summary results and made a diagnosis. The nurse and physician were blind to the screen results. Patients were reinterviewed within 96 hours by a mental health professional (MHP) blind to previous results. The nurses' interviews ranged between 1.5 and 3.5 minutes for a screened positive diagnosis. Agreement between the nurse and physician diagnoses was excellent to moderate. Disagreement was usually in the direction of the physician ruling out major mental disorders in favor of subsyndromal or medical explanations. Only rarely did physicians diagnose disorders not detected by the nurse interview. Agreement between physician and MHP was moderate. Physicians using the SDDS-PC seldom made diagnoses that were not confirmed by the independent assessment of the MHP. The SDDS-PC may facilitate recognition of psychiatric disorders and minimize the physician's time in information gathering.

Adolescent↗
PubMed1997

False positive results: a challenge for psychiatric screening in primary care.

OBJECTIVE: The goal of this study was to characterize primary care patients with false positive results on screens for mental disorders. METHOD: A sample of 1,001 primary care patients completed self-administered screens and structured interviews for DSM-IV diagnoses. RESULTS: A substantial proportion of the patients with false positive screen results for at least one diagnosis met the diagnostic criteria for other psychiatric disorders. They also had significantly greater functional impairment and higher rates of recent use of mental health services than the subjects with true negative results on the screens. CONCLUSIONS: Although the positive predictive values of screens for specific mental disorders are in line with those of other medical screens, false positive results are not uncommon. This may be due in part to the sensitivity of brief screening instruments to nonspecific symptoms. The results suggest that as with other screens used in primary care, patients with false positive results on screens for mental disorders should receive clinical attention.

Adolescent↗
PubMed1997

Mental disorders and disability among patients in a primary care group practice.

OBJECTIVE: This article examines social and occupational disability associated with several DSM-IV mental disorders in a group of adult primary care outpatients. METHOD: The subjects were 1,001 primary care patients (aged 18-70 years) in a large health maintenance organization. Data on each patient's sociodemographic characteristics and functional disability, including scores on the Sheehan Disability Scale, were collected at the time of a medical visit. A structured diagnostic interview for current DSM-IV disorders was then completed by a mental health professional over the telephone within 4 days of the visit. RESULTS: The most prevalent disorders were phobias (7.7%), major depressive disorder (7.3%), alcohol use disorders (5.2%), generalized anxiety disorder (3.7%), and panic disorder (3.0%). A total of 8.3% of the patients met the criteria for more than one mental disorder. The proportion of patients with co-occurring mental disorders varied by index disorder from 50.0% (alcohol use disorder) to 89.2% (generalized anxiety disorder). Compared with patients who had a single mental disorder, patients with co-occurring disorders reported significantly more disability in social and occupational functioning. After adjustment for other mental disorders and demographic and general health factors, compared with patients with no mental disorder, only patients with major depressive disorder, bipolar disorder, phobias, and substance use disorders had significantly increased disability, as measured by the Sheehan Disability Scale. CONCLUSIONS: Primary care patients with more than one mental disorder are common and highly disabled. Individual mental disorders have distinct patterns of psychiatric comorbidity and disability.

Persons with Disabilities↗
PubMed1997

Assessing psychiatric impairment in primary care with the Sheehan Disability Scale.

OBJECTIVE: Several recent studies have documented that substantial functional impairment is associated with many of the mental disorders seen in primary care. However, brief measures of mental health-related functional impairment are not commonly applied in primary care settings. The Sheehan Disability Scale (SDS), a three-item instrument for assessing such impairment, is evaluated in this study. METHOD: A psychometric analysis of the SDS was conducted with a sample of 1001 primary care patients at Kaiser Permanente In Oakland, California. The SDS and the Symptom Driven Diagnostic System for Primary Care assessments were completed. RESULTS: The internal consistency reliability of the SDS is high, with coefficient alpha of 0.89. The construct validity was substantiated in two ways. A one-factor model fit the data quite well. Furthermore, patients with each of six psychiatric disorders had significantly higher impairment scores than those who did not. Finally, over 80 percent of the patients with mental disorder diagnoses had an elevated SDS score and nearly 50 percent of those with elevated SDS scores had at least one disorder. CONCLUSIONS: The psychometric properties of the SDS were evaluated in primary care. The internal consistency reliability was high. The analyses also lend empirical support for the construct validity. The scale is a sensitive tool for identifying primary care patients with mental health-related functional impairment, who would warrant a diagnostically-oriented mental health assessment.

Adolescent↗
PubMed1996

Subthreshold psychiatric symptoms in a primary care group practice.

BACKGROUND: The authors define 6 groups of subthreshold psychiatric symptoms that do not meet the full criteria for a DSM-IV Axis I disorder and examine the clinical significance of these symptoms in an outpatient primary care sample. METHODS: The subjects were 1001 adult primary care patients in a large health maintenance organization. Data on sociodemographic characteristics and functional impairment, including scores on the Sheehan Disability Scale, were collected at the time of the medical visit, and a structured diagnostic interview for DSM-IV disorders was completed by telephone within 4 days of the visit. Subthreshold symptoms were defined for depressive, anxiety, panic, obsessive-compulsive, drug, and alcohol symptoms. RESULTS: Subthreshold symptoms were as or more common than their respective Axis I disorders: panic (10.5% vs 4.8%), depression (9.1% vs 7.3%), anxiety (6.6% vs 3.7%), obsessive-compulsive (5.8% vs 1.4%), and alcohol (5.3% vs 5.2%) and other drug (3.7% vs 2.4%) cases. Patients with each of the subthreshold symptoms had significantly higher Sheehan Disability Scale scores (greater impairment) than did patients with no psychiatric symptoms. Many patients (22.6%-53.4%) with subthreshold symptoms also met the full criteria for other Axis I disorders. After adjusting for the confounding effects of other Axis I disorders, other subthreshold symptoms, age, sex, race, marital status, and perceived physical health status, only depressive symptoms, major depressive disorder, and, to a lesser extent, panic symptoms were significantly correlated with the impairment measures. CONCLUSIONS: In these primary care patients, the morbidity of subthreshold symptoms was often explained by confounding mental, physical, or demographic factors. However, depressive symptoms and, to a lesser extent, panic symptoms were disabling even after controlling for these factors. Primary care clinicians who detect subthreshold psychiatric symptoms should consider a broad psychiatric assessment.

Adult↗
PubMed1996

Suicidal ideation in primary care.

OBJECTIVE: To describe the prevalence and clinical characteristics of primary care patients who report suicidal ideation during the month before their medical visit. DESIGN: Analysis of a self-administered suicidal ideation screening item using sociodemographic data, treatment history, and clinical data from structured interviews. SETTING: Three Rhode Island private family practices, a South Carolina family medicine residency, and a California prepaid internal medicine group practice. PATIENTS: Adult primary care patients (N = 2,749), 18 to 70 years old, who are able to read and write English, able to complete study forms, and willing to provide informed consent. RESULTS: Sixty-seven (2.44%) of the patients reported suicidal ideation ("feeling suicidal") during the past month, and most of those patients (58.2%) received no mental health care during that time. The adjusted risk of suicidal ideation was significantly elevated for patients with self-reported fair or poor physical health (odds ratio [OR] 2.5; 95% confidence interval [CI] 1.5, 4.1), fair to poor emotional health (OR 18.0; 95% CI 8.8, 37.0), marital distress (OR 4.4; 95% CI 2.2, 8.8), and recent mental health-related work loss (OR 6.3; 95% CI 3.7, 10.5). In the California sample, patients with major depression (R 31.2; 95% CI 12.8, 76.1). generalized anxiety disorder (OR 23.4; 95% CI 8.1, 67.1), and drug abuse or dependence (OR 9.6; 95% CI 2.9, 31.6) were at increased risk of suicidal ideation. The "feeling suicidal" item identified 10 of 12 patients who acknowledged a recent plan to kill themselves. CONCLUSIONS: In these primary care patients, suicidal ideation is strongly associated with mental disorder and mental health-related functional impairment, and can be detected with a single self-report "feeling suicidal" item.

Adolescent↗
PubMed1996

Psychotic symptoms in primary care.

BACKGROUND: Psychotic symptoms include a variety of disturbances in perception, reality testing, speech, and behavior. We examine the prevalence, distribution, treatment, and functional impairment associated with psychotic symptoms in primary care patients. METHODS: Data are drawn from a recent study of adult primary care patients (N = 1001) in a large, urban, prepaid group practice. At the medical visit, patients completed a questionnaire that probed demographic characteristics, health status, and mental health care utilization. Following the visit, patients received a telephone-administered, structured psychiatric interview that included 11 psychotic symptoms. Medication prescription data were also available. Comparisons are presented of patients with and without psychotic symptoms. RESULTS: Thirty-seven (3.7%) patients reported one or more psychotic symptoms, most commonly a belief that others were spying on or following them (n = 16). As compared with patients without psychotic symptoms, a larger proportion of the patients with psychotic symptoms reported mental health-related work loss (54.1% vs 17.9%, P < .0001), suicidal ideation (21.6% vs 2.6%, P < .0001), major depressive disorder (32.4% vs 6.3%, P < .0001), bipolar disorder (29.7% vs 1.2%, P < .0001), and several other mental disorders. An antipsychotic medication had been prescribed during the previous 17 to 20 months for only two (5.4%) of the patients with psychotic symptoms. CONCLUSIONS: Psychotic symptoms were relatively common (3.7%) in this practice and were strongly associated with functional impairment and affective, anxiety, or substance use disorders. Primary care physicians are encouraged to examine patients with these mental disorders for the presence of psychotic symptoms.

Adult↗