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Biomedical subjects

S Zuckerman

Publications and source records attributed to S Zuckerman.

At least 19 recordsLinked to original sources
PubMed2001

Verb movement in acquisition and aphasia: same problem, different solutions-evidence from Dutch.

This paper focuses on verb movement in agrammatism and child language. We present data from a sentence completion experiment with 6 Dutch agrammatic aphasics and 21 Dutch-speaking children. The experiment compares completion of matrix clauses (which require verb movement) and embedded clauses (where such movement is not required) in these two populations. The results reveal a clear asymmetry: Both agrammatics and children do very well with embedded clauses but fail in 50% with the matrix clauses. It is concluded that the problem which both populations are facing is one of verb movement rather than verb inflection. An error analysis of the responses reveals that, although both agrammatics and children try to avoid movement, they apply different strategies to achieve this goal.

Adult↗
PubMed2001

Pharmacokinetics of mycophenolic acid after mycophenolate mofetil administration in liver transplant patients treated with tacrolimus.

The pharmacokinetics of mycophenolic acid (MPA) was studied after oral administration of mycophenolate mofetil (MMF) in 8 liver transplant patients. The mean (+/- SD) maximum MPA plasma concentration of 10.6 (+/- 7.5) mg/ml was achieved within 0.5 to 5 hours. The mean (+/- SD) steady-state area under the plasma concentration versus time curve (AUC(0-12)) was 40 (+/- 30.9) mg/ml/h. The mean (+/- SD) half-life was 5.8 (+/- 3.8) hours. There was poor correlation between trough blood concentrations of tacrolimus (r = -0.004) or serum creatinine (r = 0.689) with MPA AUC, while the serum bilirubin concentrations correlated (r = 0.743) well with MPA AUC, suggesting impairment in MPA conjugation in patients with liver dysfunction. The mean (+/- SD) ratio of the AUC of mycophenolic acid glucuronide (MPAG) to MPA was 64 (+/- 84), which correlated significantly with serum creatinine (r = 0.72) but not with serum bilirubin concentrations (r = 0.309), indicating accumulation of MPAG in patients with renal dysfunction. In 7 primary liver transplant patients on the same dose of MMF, the trough plasma concentrations of MPA during the first week of therapy ranged from < 0.3 to 1.5 microg/ml. The MPA concentrations increased by several folds during the next few weeks, which correlates well with increases in serum albumin concentrations. Changes in albumin appear to partially contribute to the variations in the pharmacokinetics of MPA in liver transplant patients.

Adult↗
PubMed2000

The effect of changing state health policy on hospital uncompensated care.

This paper examines the effect of changing state policy, such as Medicaid eligibility, payment generosity, and HMO enrollment on provision of hospital uncompensated care. Using national data from the American Hospital Association for the period 1990 through 1995, we find that not-for-profit and public hospitals' uncompensated care levels respond positively to Medicaid payment generosity, although the magnitude of the effect is small. Not-for-profit hospitals respond negatively to Medicaid HMO penetration. Public and for-profit hospitals respond negatively to increases in Medicaid eligibility. Results suggest that public insurance payment generosity is an effective but inefficient policy instrument for influencing uncompensated care among not-for-profit hospitals. Further, in localities with high HMO penetration or high penetration of for-profit hospitals, it may be necessary to establish explicit payments for care of the uninsured.

American Hospital Association↗
PubMed2000

Confirming insurance coverage in a telephone survey: evidence from the National Survey of America's families.

Until recently, most surveys of insurance coverage have classified people as uninsured if they have not been assigned some coverage in response to one of a series of questions about specific types of insurance. This "residual" approach to measuring uninsurance rates has not required respondents to either verify their insurance status or confirm that they are uninsured. Using the 1997 National Survey of America's Families, this paper examines the impact of a question confirming whether individuals for whom no insurance coverage is reported are, in fact, uninsured. The results of our analysis suggest that a confirmation question as part of a telephone-based survey works to lower estimates of the uninsured.

Adult↗
PubMed1999

Effect of t-tube clamping on the pharmacokinetics of mycophenolic acid in liver transplant patients on oral therapy of mycophenolate mofetil.

The aim of the study was to evaluate the effect of t-tube clamping on the pharmacokinetics of mycophenolic acid (MPA) after oral administration of mycophenolate mofetil (MMF) in primary liver transplant recipients treated with tacrolimus as the primary immunosuppressive drug. We evaluated the pharmacokinetics of MPA and its primary metabolite, mycophenolic acid glucuronide (MPAG), before and after clamping the t-tube in 8 primary liver transplant recipients treated with oral MMF and tacrolimus. The concentration of MPA and MPAG in plasma, bile, and urine samples obtained over one dosing interval was measured by high-pressure liquid chromatography. Pharmacokinetic parameters of MPA estimated before and after clamping the t-tube were compared to evaluate any significant differences at a P of.05 or less. There were no significant differences in the time to reach peak plasma concentration (1.8 +/- 1.7 v 1.0 +/- 0.5 hours), trough plasma concentration of MPA (1.1 +/- 1.4 v 1.4 +/- 1.1 microgram/mL), peak plasma concentration of MPA (10.6 +/- 7.5 v 11.1 +/- 4.6 microgram/mL), area under the plasma concentration-versus-time curve (AUC) (40.1 +/- 31.9 v 43.2 +/- 21.1 microgram/mL/h) of MPA, or the percentage of MPA that is free or unbound in the plasma (3.9% +/- 1.6% v 4.1% +/- 3.0%). There was also no significant difference in the ratio of the AUC of MPAG to MPA. These observations suggest that t-tube clamping does not affect the kinetics of MPA or MPAG and that no dosing alterations of MMF are required when the t-tube is clamped in liver transplant recipients.

Administration, Oral↗
PubMed1999

A conflict of strategies: Medicaid managed care and Medicaid maximization.

OBJECTIVE: To examine the influence of state strategies aimed at increasing federal Medicaid matching dollars on the design of states' Medicaid managed care programs. STUDY DESIGN: Data obtained from the 1996-1997 case studies of 13 states to examine how states have adapted the design of their Medicaid managed care programs in part because of maximization strategies, to accommodate the many roles and responsibilities that Medicaid has assumed over the years. PRINCIPAL FINDINGS: Our study showed that as states made the shift to managed care, some found that the responsibilities undertaken in part through maximization strategies proved to be in conflict with their Medicaid managed care initiatives. Among other things, the study revealed that most states included provisions that preserved the health care safety net, such as adapting the managed care benefit package and promoting the participation of safety net providers in managed care programs. In addition, most of the study states continued to pay special subsidies to safety net providers, including hospitals and clinics. CONCLUSIONS: States have made real progress in moving a large number of Medicaid beneficiaries into managed care. At the same time, many states have specially crafted their managed care programs to accommodate safety net providers and existing funding mechanisms. By making these adaptations states, in the long run, may compromise the central goals of managed care: controlling costs and improving Medicaid beneficiaries' access to and quality of care.

Economics, Hospital↗
PubMed1999

An alternative approach to measuring the effects of insurance market reforms.

Reforms in the small group and individual insurance markets could make it easier for the currently insured to keep their coverage, and could expand coverage by making insurance more accessible to the currently uninsured. We use data from the 1989 through 1995 Current Population Survey to measure the impact of these reforms on state-level rates of uninsurance and private health insurance coverage. Instead of examining the effect of each of the various types of insurance marker reforms, we estimate the impact of packages of reforms on insurance coverage, reflecting how policies were implemented. We find that small group reforms have done little to affect insurance coverage. Individual market reforms, on the other hand, appear to increase uninsurance rates and reduce private coverage. Our findings suggest that small group reforms may have prevented erosion of private coverage, but have not reduced the numbers of uninsured people.

Employment↗
PubMed1999

The National Survey of America's Families: an overview of the health policy component.

This report describes one aspect of "Assessing the New Federalism," a multi-year research project, started by the Urban Institute in 1996, to analyze the devolution of responsibility for social programs from the federal government to the states. The project combines case studies in 13 diverse states with analyses of data drawn from a wide range of sources, including a new household survey--the National Survey of America's Families (NSAF). The NSAF, which contains nationally representative data from almost 45,000 families, was fielded in 1997 and 1999, and is planned for 2001 and again at subsequent two-year intervals. In this paper, we provide an overview of the NSAF's purpose; the sampling approach and methods; the questionnaire content, with particular emphasis on questions of interest to health policy researchers; health policy research planned by Urban Institute staff; and the timetable for public release of the NSAF data.

Family Health↗
PubMed1998

Doctor talk and diabetes: towards an analysis of the clinical construction of chronic illness.

During the last two decades the illness narrative has emerged as a popular North American literary form. Through poignant stories, well-educated patients have recounted their struggle with disabling diseases as well as with the hospitals and health care bureaucracies from whom they seek service. However, much less has been written about the doctor's narrative construction of chronic diseases either in the process of learning medicine or through diagnosing, treating and counseling chronically ill patients. Indeed, following Kleinman's lead, the physician's narrative has been narrowly viewed as a discourse on the verifiable manifestations of pathophysiology. Drawing on contemporary theories of storytelling--including the conception of narrative as conversational interaction--the present paper argues that doctor narratives are equally complex if quite different than patient stories. Indeed, through an analysis of doctor talk centering on diabetes mellitus collected in several distinct venues--case presentations, narrative interviews and medical consultations--it is argued that physician stories not only employ very evocative tropes, but that these stories combine didactic, rhetorical and soterological elements in the telling. The research was conducted at two, urban family practice training sites in Chicago.

Attitude of Health Personnel↗
PubMed1998

Urban health care in transition: challenges facing Los Angeles County.

The authors examine the Medicaid Section 1115 Demonstration Project currently underway in Los Angeles County. The waiver was designed as part of a response to a financial crisis the Los Angeles County Department of Health Services (LACDHS) faced in 1995. It provides financial relief to give the county time to restructure its system for serving the medically indigent population. Los Angeles County's goal is to reduce its traditional emphasis on emergency room and hospital care by building an integrated system of community-based primary, specialty, and public health care. This case study describes activities completed through the spring of 1997, approximately 1 year after the waiver was approved.

Community Health Services↗
PubMed1996

Financial pressure and competition. Changes in hospital efficiency and cost-shifting behavior.

Using data from the American Hospital Association and the Medicare program, the authors analyzed the effects of financial pressure and market competition on changes in several measures of performance of 1,435 acute care hospitals between 1987 and 1989. Over the observation period, the least profitable hospitals constrained their growth in total expenses to half that for the most profitable hospitals (13.3% versus 27.6%) by limiting the growth of their staffs and their total assets. These changes were associated with a reduction in inefficiency of 1.8% (11.2%) compared with a very slight increase in inefficiency for the highest profit group. Similarly, hospitals in highly competitive markets controlled expenses relative to those in the least competitive areas. However, they also experienced slower revenue growth than did less competitive hospitals so that, in relative terms, their profit rates fell. The authors found no evidence to suggest that financial pressures created by either low profits or market competition resulted in hospitals engaging in cost-shifting. The authors conclude that health care reforms or market forces that put financial pressures on hospitals can result in cost-containment and improved efficiency without significant cost-shifting.

Cost Allocation↗
PubMed1996

Preferred provider organizations and physician fees.

Preferred provider organizations (PPOs) represent a form of managed care in which providers agree to accept discounted fees in exchange for the expectation that their patient volume will increase or at least be maintained. Managed care plans that rely on discounted fee-for-service (FFS) payments have increased from about 10 plans in 1981 to over 700 plans in 1994. In this study, we document levels of discounts achieved by two large national insurers and discuss how the size of the discount varies by type of service and how the discounted rates relate to Medicare fees. Our results show that, despite achieving large discounts (approximately 10 20 percent) relative to their indemnity plans, the two nationwide PPOs studied here pay at rates substantially above Medicare levels.

Fee-for-Service Plans↗
PubMed1995

Tacrolimus analysis: a comparison of different methods and matrices.

We determined the through blood and plasma concentrations of tacrolimus from the day of transplantation through 30 days posttransplantation in four liver and four kidney transplant patients by three different methods. The first method involved a solid phase extraction of the blood or plasma using Sep-Pak columns (SPs) followed by quantitation of tacrolimus using an enzyme-linked immunosorbent assay (ELISA); the second method involved a liquid-liquid extraction using methylene chloride (MC) followed by quantitation of tacrolimus using the ELISA, and the third method involved a high-performance liquid chromatography (HPLC) fractionation of the extract obtained from the solid-phase extraction and quantitation of tacrolimus in the fractions by ELISA. The trough plasma tacrolimus concentrations ranged from 0.1 to 5.2 ng/ml. While the trough plasma concentrations of tacrolimus were similar and independent of the method of analysis in kidney transplant patients and in liver transplant patients with normal biochemical profile, in patients with liver dysfunction, tacrolimus plasma concentrations were higher when measured by SP-ELISA and MC-ELISA methods as compared to the HPLC-ELISA method. In plasma samples obtained from liver transplant patients with liver dysfunction, the presence of some metabolites that cross-reacted with the antibody used in the ELISA could be documented in the HPLC fraction corresponding to the metabolites. This indicates that while tacrolimus metabolites that cross-react significantly with the antibody used in the ELISA do not accumulate in kidney transplant patients, they can appear in the plasma of patients, they can appear in the plasma of patients with liver dysfunction. The trough blood tacrolimus concentrations in patients were significantly higher than the corresponding plasma concentrations and ranged from 1.4 to 107 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatography, High Pressure Liquid↗
PubMed1995

Inhibitory effect of indomethacin on prostacyclin receptor-mediated cerebral vascular responses.

The present study addresses the hypothesis that indomethacin, in addition to blocking prostaglandin synthesis, directly inhibits prostacyclin receptor-mediated cerebral vascular responses. To test this hypothesis, the effects of indomethacin on pial arteriolar dilation in response to the prostacyclin receptor agonist iloprost were investigated using a cranial window technique in newborn pigs. Topically applied iloprost resulted in dose-dependent pial arteriolar dilation and concomitant increases in cortical adenosine 3',5'-cyclic monophosphate (cAMP). Indomethacin (5 mg/kg iv + 10(-4) M topically) greatly reduced both the vasodilation and the increase in cortical cAMP in response to iloprost. In contrast, indomethacin did not attenuate beta-adrenoreceptor-mediated vasodilation and the increase in cortical cAMP in response to isoproterenol. Aspirin (50 mg/kg iv + 10(-3) M topically) did not affect pial arteriolar dilation or the increase in cortical cAMP in response to iloprost. Unlike indomethacin, aspirin was not effective in inhibiting prostanoid-associated cerebral vasodilation and increase in cortical cAMP in response to hypercapnia. The present data suggest that indomethacin selectively inhibits prostacyclin receptor-mediated responses in the newborn pig cerebral circulation. The combination of highly effective inhibition of prostaglandin H synthase and prostacyclin receptor-mediated vasodilation may contribute to the increased efficacy of indomethacin compared with other prostaglandin H synthase inhibitors in blocking certain vasodilator responses associated with prostanoids.

Animals↗
PubMed1995

Clinical pharmacokinetics of tacrolimus.

Tacrolimus, a novel macrocyclic lactone with potent immunosuppressive properties, is currently available as an intravenous formulation and as a capsule for oral use, although other formulations are under investigation. Tacrolimus concentrations in biological fluids have been measured using a number of methods, which are reviewed and compared in the present article. The development of a simple, specific and sensitive assay method for measuring concentrations of tacrolimus is limited by the low absorptivity of the drug, low plasma and blood concentrations, and the presence of metabolites and other drugs which may interfere with the determination of tacrolimus concentrations. Currently, most of the pharmacokinetic data available for tacrolimus are based on an enzyme-linked immunosorbent assay method, which does not distinguish tacrolimus from its metabolites. The rate of absorption of tacrolimus is variable with peak blood or plasma concentrations being reached in 0.5 to 6 hours; approximately 25% of the oral dose is bioavailable. Tacrolimus is extensively bound to red blood cells, with a mean blood to plasma ratio of about 15; albumin and alpha 1-acid glycoprotein appear to primarily bind tacrolimus in plasma. Tacrolimus is completely metabolised prior to elimination. The mean disposition half-life is 12 hours and the total body clearance based on blood concentration is approximately 0.06 L/h/kg. The elimination of tacrolimus is decreased in the presence of liver impairment and in the presence of several drugs. Various factors that contribute to the large inter- and interindividual variability in the pharmacokinetics of tacrolimus are reviewed here. Because of this variability, the narrow therapeutic index of tacrolimus, and the potential for several drug interactions, monitoring of tacrolimus blood concentrations is useful for optimisation of therapy and dosage regimen design.

Drug Interactions↗
PubMed1994

Measuring hospital efficiency with frontier cost functions.

This paper uses a stochastic frontier multiproduct cost function to derive hospital-specific measures of inefficiency. The cost function includes direct measures of illness severity, output quality, and patient outcomes to reduce the likelihood that the inefficiency estimates are capturing unmeasured differences in hospital outputs. Models are estimated using data from the AHA Annual Survey, Medicare Hospital Cost Reports, and MEDPAR. We explicitly test the assumption of output endogeneity and reject it in this application. We conclude that inefficiency accounts for 13.6 percent of total hospital costs. This estimate is robust with respect to model specification and approaches to pooling data across distinct groups of hospitals.

Data Collection↗
PubMed1994

CO2 and cerebral circulation in newborn pigs: cyclic nucleotides and prostanoids in vascular regulation.

The role of cyclic nucleotides and prostanoids in cerebrovascular reactivity to increased carbon dioxide was investigated in anesthetized and artificially ventilated newborn pigs equipped with closed cranial windows. Pial arteriolar diameter was measured, and cortical periarachnoid cerebrospinal fluid (CSF) was collected from beneath the cranial window for determination of adenosine 3',5'-cyclic monophosphate (cAMP), guanosine 3',5'-cyclic monophosphate (cGMP), and prostanoids. Progressively increasing arterial PCO2 (PaCO2) from normocapnia (33 +/- 1 mmHg) to hypercapnia (final PaCO2, 83 +/- 2 mmHg) resulted in dose-dependent pial arteriolar dilation and concomitant increases in cAMP, cGMP, and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) in cortical CSF. N omega-methyl-L-arginine, N omega-nitro-L-arginine, N omega-nitro-L-arginine methyl ester, methylene blue, and LY 83583 did not inhibit cerebral vasodilation or the increases in cortical cAMP/cGMP induced by hypercapnia. Indomethacin abolished the vasodilatory response to hypercapnia and attenuated the hypercapnia-induced increases in cAMP and cGMP. Prostacyclin analogues increased both cAMP and cGMP levels in cortical CSF and induced pial arteriolar dilation (iloprost > carbaprostacyclin). The present data suggest that in newborn pigs cyclic nucleotides are involved in cerebral vasodilation in response to hypercapnia via a prostanoid-dependent mechanism.

Amino Acid Oxidoreductases↗