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Biomedical subjects

R P Schwartz

Publications and source records attributed to R P Schwartz.

At least 19 recordsLinked to original sources
PubMed2001

Decreasing the variability observed in urine analysis.

Urine analysis is affected significantly by biological variability. The objective of this study was to study the feasibility of reducing the biological variability of excretion of various analytes in urine, especially albumin in children with diabetes, by mixing small volumes of early morning samples. Twenty-two male children with type 1 diabetes collected early morning aliquots of approximately 10 ml of urine on 3 consecutive days and kept them refrigerated in sealed containers. The urine collection was repeated every 4-6 months in the diabetic children. Ten normal children and 10 normal adults participated as controls. The specimens were analyzed individually and as mixed samples for each subject. Mixing the 3 urine samples before analysis decreased the biological variability of all urine assays (albumin, glucose, creatinine, total protein, potassium). The diabetic children had 3 times higher variability of urine albumin (as a ratio to creatinine) compared to normal children, when the urine samples were collected individually (61% vs 19%, respectively). The variability in the diabetic children decreased when the 3 specimens were analyzed as a single sample after mixing, especially when urine albumin was expressed as a ratio to creatinine. Blood glycated hemoglobin levels correlated better with urine glucose levels when 3 urine samples were mixed before analysis.

Adolescent↗
PubMed2000

Nutritional rickets in African American breast-fed infants.

OBJECTIVE: To analyze the characteristics of infants and children diagnosed with nutritional rickets at two medical centers in North Carolina in the 1990s. STUDY DESIGN: The physical and radiographic findings, calcium, phosphorus, alkaline phosphatase, and 25-hydroxyvitamin D levels of infants and children diagnosed with nutritional rickets at two medical centers were reviewed. Breast-feeding data were obtained from the North Carolina Women, Infants and Children Program (WIC). RESULTS: Thirty patients with nutritional rickets were first seen between 1990 and June of 1999. Over half of the cases occurred in 1998 and the first half of 1999. All patients were African American children who were breast fed without receiving supplemental vitamin D. The average duration of breast-feeding was 12.5 months. The age at diagnosis was 5 to 25 months, with a median age of 15.5 months. Growth failure was common: length was <5th percentile in 65% of cases, and weight was <5th percentile in 43%. CONCLUSION: Factors that may have contributed to the increase in referrals of children with nutritional rickets include more African American women breast-feeding, fewer infants receiving vitamin D supplements, and mothers and children exposed to less sunlight. We recommend that all dark-skinned breast-fed infants and children receive vitamin D supplementation.

Black People↗
PubMed2000

A sensitive solid-phase fluoroimmunoassay for detection of opiates in urine.

An automated flow fluorometer designed for kinetic binding analysis was adapted to develop a solid-phase competitive fluoroimmunoassay for urinalysis of opiates. The solid phase consisted of polymer beads coated with commercial monoclonal antibodies (MAbs) raised against morphine. Fluorescein-conjugated morphine (FL-MOR) was used as the fluorescein-labeled hapten. The dissociation equilibrium constant (K(D)) for the binding of FL-MOR to the anti-MOR MAb was 0.23 nM. The binding of FL-MOR to the anti-MOR MAb reached steady state within minutes and was displaced effectively by morphine and other opiates. Morphine-3-glucuronide (M3G), the major urinary metabolite of heroin and morphine, competed effectively with FL-MOR in a concentration-dependent manner for binding to the antimorphine MAb and was therefore used to construct the calibration curve. The sensitivity of the assay was 0.2 ng/mL for M3G. The assay was effective at concentrations of M3G from 0.2 to 50 ng/mL, with an IC50 of 2 ng/mL. Other opiates and heroin metabolites that showed >50% crossreactivity when present at 1 microg/mL included codeine, morphine-6-glucuronide, and oxycodone. Methadone showed very low crossreactivity (<5%), which is a benefit for testing in patients being treated for opiate addictions. The high sensitivity of the assay and the relatively high cutoff value for positive opiate tests allows very small sample volumes (e.g., in saliva or sweat) to be analyzed. A double-blind comparison using 205 clinical urine samples showed good agreement between this single-step competitive assay and a commercially performed enzyme multiplied immunoassay technique for the detection of opiates and benzoylecgonine (a metabolite of cocaine).

Antibodies, Monoclonal↗
PubMed1999

Assessment of an automated solid phase competitive fluoroimmunoassay for benzoylecgonine in untreated urine.

A new solid phase fluoroimmunoassay using a fully automated flow fluorometer adapted for urinalysis of drug metabolites is described. Fluorescein-conjugated benzoylecgonine (FL-BE) and monoclonal antibodies (mAb) against benzoylecgonine (BE) were the reagents used for demonstration. The solid phase consisted of anti-BE mAbs immobilized on the surface of polymethyl methacrylate (PMMA) beads. Free BE in solution competed with FL-BE and reduced bead-bound fluorescence in a concentration-dependent manner. The binding of FL-BE to the anti-BE mAb reached steady-state within minutes. FL-BE was not bound by uncoated beads nor beads coated with non-specific proteins or IgG. The signal-to-noise ratio was 33, and the sensitivity of the assay was 2 ng ml(-1) for BE. The effective concentration of BE was 1 to 100 ng ml(-1), with an IC50 value of 12 ng ml(-1). The mAb showed equal affinities for BE, cocaine, and cocaethylene, but a five order-of-magnitude lower affinity for ecgonine and ecgonine methylester. In a double-blind comparison using clinical urine samples, the data from this single-step competitive assay had excellent agreement with results obtained using a fiber-optic biosensor (FOB), and the EMIT assay performed commercially. The assay provided kinetic data rapidly and can be used to detect small analytes for which antibodies and fluorescein conjugates are available. The affinity of the mAb for FL-BE, calculated from kinetic analysis of the time course of the on and off reaction, was 2.25 x 10(-9) M.

Antibody Affinity↗
PubMed1999

Familial medullary thyroid carcinoma: presymptomatic diagnosis and management in children.

Two kindreds with familial medullary thyroid carcinoma (MTC) are described in which affected family members had variable clinical and pathologic manifestations. Genetic testing in 2 children from one kindred revealed a mutation in exon 10, codon 618 (TGC to AGC) in the extracellular cysteine-rich region of the RET gene. In this kindred an 11-year-old had microscopic evidence of MTC; however, a 17-year-old had no evidence of pathology on thyroidectomy. In a second kindred a rare mutation in exon 14, codon 804 (GTG to TTG) of the intracellular tyrosine kinase region of the RET gene was detected. In this kindred MTC has occurred in the 4th to 5th decades of life, with a clinical spectrum in mutation-positive family members ranging from no disease and C-cell hyperplasia to carcinoma with lymph node metastasis; a 7-year-old with the mutation and a normal response to provocative testing was also identified. Management recommendations in children from families with clearly defined familial MTC may be individualized to reflect emerging genotype-phenotype correlations.

Adolescent↗
PubMed1999

Hypocalcemic tetany in a toddler with undiagnosed rickets.

A 17-month-old black girl presented to the pediatric emergency department with sudden onset of her hands and feet "drawing up." A diagnosis of vitamin D deficiency rickets with tetany was made on a history of exclusive breast-feeding, low serum calcium, phosphorus, and 25-hydroxyvitamin D levels, and bone radiographs. Nutritional rickets should be considered in the differential diagnosis of acute hypocalcemia.

Acute Disease↗
PubMed1999

A 12-year follow-up of a methadone medical maintenance program.

Methadone Medical Maintenance (MDM) is an alternative for treatment of stable methadone maintained individuals. It involves a monthly physician's visit, at which methadone take-home doses are dispensed to last until the next appointment. The safety and efficacy of this treatment modality is currently under investigation. The purpose of this study was to evaluate the long-term safety and efficacy of MDM in a methadone program in Baltimore. A sample of 21 patients was enrolled in the study and followed for 12 years. They were evaluated once a month by a primary care physician affiliated with a methadone clinic who collected urine toxicology samples and dispensed the monthly methadone dose. The results showed that only 6 (28.6%) patients dropped out during the 12 years of the study. Twelve (0.5%) of 2,290 urine samples collected were positive for drugs. No methadone overdose or diversion was observed. Participants reported significant improvement in their quality of life. The results of this study support the safety and efficacy of medical maintenance of stable methadone maintained individuals.

Adult↗
PubMed1999

The relationship between parental history and substance use severity in drug treatment patients.

The authors explored the relationship between the history of parental problematic alcohol and drug use and their adult children's alcohol and drug use disorders. Subjects were 347 admissions to an outpatient substance abuse program. There was a positive relationship between the number of parents affected by alcohol and/or drug problems and the percentage of probands with co-existing alcohol and drug use disorders for probands with alcohol use disorders but not for those with only drug abuse. Probands with two affected parents had significantly higher alcohol abuse scores and drug, family, and psychiatric composite test scores than those with a negative family history. This preliminary study indicates that the severity of a proband's substance use disorder may be influenced by parental substance use history.

Adult↗
PubMed1997

Suicidal ideation and behavior and noncompliance with the medical regimen among diabetic adolescents.

OBJECTIVE: To examine (1) the 1-year and lifetime prevalence of suicidal thoughts and behavior among adolescents with insulin-dependent diabetes mellitus (IDDM), (2) the relationship between suicidal thoughts and serious noncompliance with the medical regimen, and (3) factors including psychiatric disorder, self-efficacy expectations, and hopelessness that might mediate the relationship between suicidal thoughts and noncompliance. METHOD: Semistructured and structured interview instruments and self-report questionnaires were used to determine history of suicidal thoughts and behavior, serious noncompliance with the medical regimen, current psychiatric disorder, hopelessness, and self-efficacy expectations among 91 adolescents attending outpatient clinic appointments. RESULTS: The rate of suicidal ideation among the diabetic adolescents was higher than expected, but the rate of suicide attempts was comparable with that reported for the general population. Suicidal thoughts were strongly associated with serious noncompliance with the medical regimen. Duration of IDDM and psychiatric diagnosis were related to both suicidal ideation within the previous year and lifetime suicidal ideation. Diagnosable psychiatric disorder and not living in a two-parent home were related to noncompliance with medical treatment. CONCLUSIONS: Suicidal thoughts and serious noncompliance with the medical regimen are strongly associated among diabetic teenagers, and psychiatric disorder is a common correlate of both.

Adolescent↗
PubMed1996

New developments in employee assistance programs.

Employee assistance programs have developed from alcoholism assessment and referral centers to specialized behavioral health programs. Comprehensive employee assistance programs are defined by six major components: identification of problems based on job performance, consultation with supervisors, constructive confrontation, evaluation and referral, liaison with treatment providers, and substance abuse expertise. Other services have been added as enhancements to the basic model and include managed behavioral health activities and professional assistance committees, which provide services for impaired professionals and executives. Recent developments in the field are illustrated through examples from the experience of the employee assistance program at the University of Maryland Medical System in Baltimore.

Alcoholism↗
PubMed1995

Four years experience of a hospital's impaired physician committee.

Physician impairment contributes to patient morbidity, malpractice claims, physician license loss and suicide. This paper describes four years of experience of the University of Maryland's Professional Assistance Committee. The committee is composed of medical staff members. Its mission is to help impaired physicians obtain assessment, treatment and monitoring, and to protect patients from harm. The committee has evaluated 23 cases over the past four years. Ten were credential checks, and 13 investigations of active problems. Eight of the 23 cases were for alcohol, eight for drug, and seven for behavioral problems. Only one person lost medical staff privileges. The committee has been well accepted by the medical staff and hospital administration and can be easily reproduced in other hospitals.

Credentialing↗
PubMed1993

Rehabilitation for adults with severe mental illness and substance use disorders. A clinical trial.

Faced with many patients with comorbid severe mental illness and substance use disorders, a university-affiliated, inner-city community mental health center and a psychosocial rehabilitation center initiated this clinical trial assessing a program to care for these patients. Fifty-four patients, age 18 to 40, with either schizophrenia or major affective disorder and a substance use disorder were randomly assigned to usual community mental health center and rehabilitation services with or without an innovative group and intensive case management program. One-year follow-ups detected no significant advantages on patient outcomes for adding the innovative program to usual services. Failure to engage patients in the experimental program posed a major and enduring barrier to treatment, despite intensive case management. Future efforts must give greater consideration to effective engagement techniques and patients' readiness for active treatment.

Adolescent↗