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Biomedical subjects

L Ku

Publications and source records attributed to L Ku.

At least 37 records · Page 2Linked to original sources
PubMed1995

Reproductive health care delivery. Patterns in a changing market.

Providers of reproductive health services, including clinics and office-based physicians, face new challenges as the American health system progresses toward managed care. Although services for low-income women are often subsidized, the average out-of-pocket payments for reproductive health services are the same for women with incomes below and above 200% of the poverty level. Although many women, especially those classified as low income, use clinics, most say that they would prefer to receive care in a private physician's office and in a place where they can get general health care as well. Multivariate analyses indicate the importance of type of insurance and source of primary health care in affecting a woman's selection of her reproductive health care provider. Specialized providers such as family planning clinics need to consider how they can blend with managed care plans.

Adult↗
PubMed1994

Epitope mapping of the alpha-chain of the insulin-like growth factor I receptor using antipeptide antibodies.

Insulin-like growth factor I (IGF I) is an important mitogen for vascular smooth muscle cells (VSMC). The IGF I receptor (IGF IR) is a heterotetramer composed of two cross-linked extracellular alpha-chains and two membrane-spanning beta-chains that contain a tyrosine-kinase domain. It has a high degree of sequence similarity to the insulin receptor (IR), and the putative ligand-specific binding site has been localized to a cysteine-rich region (CRR) of the alpha-chain. To obtain insights into antigenic determinants of the IGF IR, we raised a panel of site-specific polyclonal antibodies against short peptide sequences N-terminal to and within the CRR. Several antibodies raised against linear epitopes within the CRR bound to solubilized and native rat and human IGF IR by ELISA, did not cross-react with IR, but unexpectedly failed to inhibit 125I-IGF I binding. A polyclonal antibody directed against a 48-amino acid synthetic peptide, corresponding to a region of the CRR postulated to be essential for ligand binding, failed to react with either solubilized, reduced or intact IGF IR. Three antibodies specific for the N-terminus of the alpha-chain reacted with solubilized and native IGF IR. One of these, RAB 6, directed against amino acids 38-44 of the IGF IR, inhibited 125I-IGF I binding to rat aortic smooth muscle cells (RASM) and to IGF IR/3T3 cells (overexpressing human IGF IR) by up to 45%. Immunohistochemical analysis revealed strong IGF IR staining in the medial smooth muscle cell layer of rat aorta. These findings are consistent with a model wherein conformational epitopes within the CRR and linear epitopes within the N-terminus of the alpha-chain contribute to the IGF I binding pocket. These antibodies should provide a valuable tool to study structure-function relationships and in vivo regulation of the IGF IR.

Amino Acid Sequence↗
PubMed1994

Fibroblast growth factor regulates insulin-like growth factor-binding protein production by vascular smooth muscle cells.

Insulin-like growth factor I is an important mitogen for vascular smooth muscle cells, and its effects are regulated by several binding proteins. Western ligand blotting of conditioned medium from rat aortic smooth muscle cells detected a 24 kDa binding protein and a 28 kDa glycosylated variant of this protein, consistent with insulin-like growth factor binding protein-4 by size. Low amounts of a glycosylated 38 to 42 kDa doublet (consistent with binding protein-3) and a 31 kDa non-glycosylated protein also were present. Basic fibroblast growth factor markedly increased secretion of the 24 kDa binding protein and its 28 kDa glycosylated variant. This effect was dose- and time-dependent and was inhibited by co-incubation with cycloheximide. Crosslinking of [125I]-insulin-like growth factor I to cell monolayers revealed no surface-associated binding proteins, either basally or after agonist treatment. Induction of binding protein production by fibroblast growth factor at sites of vascular injury may be important in vascular proliferative responses in vivo.

Animals↗
PubMed1994

State responses to the Medicaid spending crisis: 1988 to 1992.

In recent years the growth of Medicaid spending has been a serious state budgetary problem. Between 1988 and 1992, state Medicaid expenditures increased at an average annual rate of 21 percent. Even when accounting for funds from special revenue programs, such as provider tax and donation programs, state Medicaid spending increased by 16 percent each year between 1988 and 1992, which is far higher than in previous years. This rapid expenditure growth occurred when states were having economic slowdowns and facing fiscal pressures in many other areas. Using a case study approach, we investigated the strategies used by nine states to address the recent surge in Medicaid spending. Despite fiscal pressures, the states generally avoided large-scale cutbacks in Medicaid. Instead they implemented a wide range of budgetary actions to reduce the effect of Medicaid growth, including increment program cutbacks, constraining other budgetary sectors, shifting program costs to the federal government, and raising state taxes.

Budgets↗
PubMed1993

Regulation of insulin-like growth factor I receptors on vascular smooth muscle cells by growth factors and phorbol esters.

Insulin-like growth factor I (IGF I) is an important mitogen for vascular smooth muscle cells. To characterize regulation of vascular IGF I receptors, we performed radioligand displacement experiments using rat aortic smooth muscle cells (RASMs). Serum deprivation for 48 hours caused a 40% decrease in IGF I receptor number. Exposure of quiescent RASMs to platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), or angiotensin II (Ang II) caused a 1.5-2.0-fold increase in IGF I receptors per cell. After FGF exposure, there was a marked increase in the mitogenic response to IGF I. IGF I downregulated its receptors in the presence of platelet-poor plasma. Stimulation of protein kinase C (PKC) by exposure of quiescent RASMs to phorbol 12-myristate 13-acetate caused a biphasic response in IGF I binding; there was a 42% decrease in receptor number at 45 minutes and a 238% increase at 24 hours. To determine the role of PKC in growth factor-induced regulation of IGF I receptors, we downregulated PKC by exposing RASMs to phorbol 12,13-dibutyrate (PDBu) for 48 hours. PDGF- and FGF- but not Ang II-mediated upregulation of IGF I receptors was completely inhibited in PDBu-treated cells. Thus, acute PKC activation by phorbol esters inhibits IGF I binding, whereas chronic PKC activation increases IGF I binding. PDGF and FGF but not Ang II regulate vascular IGF I receptors through a PKC-dependent pathway. These data provide new insights into the regulation of vascular smooth muscle cell IGF I receptors in vitro and are of potential importance in characterizing vascular proliferative responses in vivo.

Angiotensin II↗
PubMed1993

Young men's risk behaviors for HIV infection and sexually transmitted diseases, 1988 through 1991.

OBJECTIVES: This paper analyzes age- and period-related changes in risk behaviors for human immunodeficiency virus (HIV) infection and sexually transmitted diseases among young men in the United States between 1988 and 1991. METHODS: Data were from the 1988 and 1991 waves of the National Survey of Adolescent Males. The 1988 survey was a nationally representative survey of 1880 males aged 15 through 19 years. The 1991 survey was a longitudinal follow-up of 1676 males aged 17 through 22 years. RESULTS: As they aged, the young men increased their levels of sexual activity and decreased their condom use. Period-related changes between 1988 and 1991 were examined by comparing similar cohorts of 17.5- through 19-year-old men: there were signs that sexual activity and intravenous drug injection increased, but condom use did not change significantly. In 1991 51% of the young men said they were occasionally "high" during sex, a state that is related to reduced condom use. CONCLUSIONS: Early progress in fostering safer behaviors among young men slowed and possibly stopped as the nation entered the 1990s. Prevention efforts need to be renewed and should focus on older youth and young adults.

Adolescent↗
PubMed1990

Deciphering Medicaid data: issues and needs.

The wide range of data bases that can be used for Medicaid analyses and research are reviewed in this article. The Health Care Financing Administration, State Medicaid agencies, and other groups have developed useful data bases and made them available to the public. Efforts could be made to obtain better quality national data, including annual reports on State participation, expenditures and program characteristics, and person-based data bases about medicaid clients and services. State-level analyses and research could be enhanced and disseminated more widely. More complex data collection and analysis efforts are an inevitable tradeoff for the flexibility of the Federal-State structure of Medicaid.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1990

The attitudes of physicians toward health care cost-containment policies.

This study analyzed physician attitudes toward a variety of health care cost-containment policies, based on a national survey of 500 practicing doctors in 1984. Reactions to 23 policies were simplified to nine common themes using factor analysis. Although there was great diversity in views, physicians generally favored policies that increased responsibilities or costs for patients and disfavored policies that decreased physicians' autonomy of practice. For most policies, practice characteristics (specialty; type of practice, e.g., solo or group, salaried or self-employed; membership in medical societies; or percent of time in direct patient care) were not significant determinants of attitudes. Physicians who were more "conservative" with respect to the health care system tended to favor policies that shifted cost to patients, while more "liberal" doctors were more supportive of using prepaid health care, reducing the intensity of care, or selecting efficient providers. Overall, this study indicates that physicians still place a high value on their professional autonomy.

Attitude of Health Personnel↗
PubMed1985

Base modification and cloning efficiency of oligodeoxyribonucleotides synthesized by the phosphoramidite method: methyl versus cyanoethyl phosphorus protection.

We have found large oligodeoxyribonucleotides (50-120 bases) synthesized with N,N-dialkylmethylphosphoramidites to have considerably lower cloning efficiencies than biological DNA. As evidenced by HPLC analysis, these large fragments contain as much as 30% thymidine conversion to 3-methylthymidine. If cyanoethyl- instead of methyl-phosphorous protection is employed, as anticipated, no thymidine methylation is noted. More importantly, large fragments produced by N,N-diisopropylcyanoethyl-phosphoramidite coupling show cloning efficiencies indistinguishable from biological DNA.

Amides↗
PubMed1984

Construction and evaluation of an instrument for the automated synthesis of oligodeoxyribonucleotides.

The details for constructing an easily used and maintained laboratory instrument capable of routine oligodeoxyribonucleotide synthesis are presented. The synthesizer consists of relatively inexpensive, commercially available components and is controlled by an Apple IIe computer. Since reagents are distributed from pressurized reservoirs through a liquid manifold by opening solenoid-activated valves, no pump is required. More than 600 oligomers containing up to 122 bases have been produced with a condensation cycle time of approximately 15 min with apparent coupling yields of 98.5%. A unique bidirectional flow reactor and controlled reagent distribution system provide for rapid mass transfer during solvent and reactant equilibrations and for long-term stability of reagent solutions. Aspects of the system should also find use in other solid-phase synthetic and analytical strategies.

Automation↗
PubMed1984

Inhibition of fibronectin binding to matrix components by nonenzymatic glycosylation.

We examined the effect of nonenzymatic glycosylation on the ability of fibronectin, an extracellular glycoprotein that interacts with cell surfaces and matrix components, to bind to collagen and heparin. Nonenzymatic glycosylation was accomplished by incubation of the protein with glucose, both cold and [14C]-labeled, and documented by measurement of ketoamine-bound carbohydrate with the thiobarbituric acid assay. Effect on binding was assessed with affinity chromatography on heparin-Sepharose and gelatin-Sepharose, and with an in vitro assay that detects complexation of fibronectin with [3H]-heparin. Glycosylated fibronectin did not bind to these immobilized matrix components, and in vitro binding of the glycosylated protein was reduced compared with that of nonglycosylated fibronectin. Inhibition of heparin binding in the in vitro assay was observed even with levels of glycosylation about threefold those of control, which is comparable to the degree of glycosylation determined in fibronectin isolated from plasma of two patients with uncontrolled diabetes. The findings indicate that nonenzymatic glycosylation of fibronectin inhibits its binding to connective tissue components, and suggest that this process contributes to faulty integrity of extracellular matrices in diabetes.

Chromatography, Affinity↗
PubMed1984

Glomerular polyol accumulation in diabetes and its prevention by oral sorbinil.

Although enhanced activity of the polyol pathway has been implicated in the pathogenesis of certain complications of diabetes, evidence that aldose reductase activity and sorbitol content are increased in the characteristic tissue site of the diabetic renal lesion has been lacking. We therefore measured polyols in glomeruli isolated from control and streptozotocin-diabetic rats, and assessed whether changes in diabetic glomeruli could be prevented by oral administration of the aldose reductase inhibitor sorbinil . Compared with control, polyol content of glomeruli isolated from diabetic rats was increased 10-fold and fourfold at 6 and 9 wk, respectively, after induction of diabetes, but was unchanged in glomeruli from rats treated with sorbinil throughout the experimental periods. In contrast, glomerular myo-inositol content was reduced in diabetic samples; this fall in myo-inositol levels was also completely prevented by sorbinil . These results establish that glomeruli contain aldose reductase activity and provide the first demonstration that glomerular polyol content increases while myo-inositol content decreases in diabetes and that oral sorbinil prevents these changes despite persistent hyperglycemia.

Aldehyde Reductase↗
PubMed1983

Age-related changes in sulfation of basement membrane glycosaminoglycans.

Alterations in heparan sulfate, the principal glycosaminoglycan species in glomerular basement membrane, have been proposed as contributory to permeability changes in nephropathic disorders. In the present study, the extent of sulfation of glycosaminoglycans isolated from pronase digests of human glomerular basement membrane, obtained from subjects 15-89 years old, was examined. The sulfate to hexuronic acid ratio significantly diminished as a function of increasing age. These results suggest that decreased sulfation of glycosaminoglycans and consequent reduction in net negative charge alters permselective properties of the glomerular basement membrane with aging.

Adolescent↗
PubMedDate not supplied

Welfare and immigration reforms: unintended side effects for Medicaid.

Welfare reform and changes in immigrants' eligibility may lead to significant reductions in Medicaid caseloads, even though many states are expanding Medicaid eligibility rules to accommodate changes under the new welfare programs. In 1996, for the first time in almost a decade, Medicaid participation of adults and children fell about 2 percent, and further reductions seem likely in 1997. The gradual restrictions on new immigrants also will affect future caseloads. Although new initiatives such as the State Children's Health Insurance Program (CHIP) should expand health coverage for children, the welfare reform and immigration changes will disproportionately lead to loss of insurance among adults.

Adult↗
PubMedDate not supplied

Left out: immigrants' access to health care and insurance.

Recent policy changes have limited immigrants' access to insurance and to health care. Fewer noncitizen immigrants and their children (even U.S.-born) have Medicaid or job-based insurance, and many more are uninsured than is the case with native citizens or children of citizens. Noncitizens and their children also have worse access to both regular ambulatory and emergency care, even when insured. Immigration status is an important component of racial and ethnic disparities in insurance coverage and access to care.

Adult↗
PubMedDate not supplied

Older, but not wiser: how men get information about AIDS and sexually transmitted diseases after high school.

CONTEXT: As they reach adulthood, young men are less likely to use condoms and are at increased risk for exposure to AIDS and other sexually transmitted diseases (STDs). Little is known about which prevention efforts reach men in their 20s. METHODS: Longitudinal data from the 1988, 1990-1991 and 1995 waves of the National Survey of Adolescent Males are used to identify sources of information about AIDS and STDs among 1,290 young men aged 22-26. Information receipt from four main sources, the topics covered by each source and the personal characteristics associated with getting more information are all explored. RESULTS: Twenty-two percent of men surveyed discussed disease prevention topics with a health provider in the last year, 48% attended a lecture or read a brochure, 51% spoke to a partner, friend or family member, and 96% heard about AIDS or STDs from the media (e.g., television advertisements, radio or magazine). Excluding media sources, 30% of young men reported getting no STD or AIDS prevention messages in the last year. Being black or Hispanic, having had a physical exam or an AIDS test in the last year, and having discussions about AIDS or STDs with parents or a health care provider in the past were associated with receiving more information. CONCLUSIONS: Although young men who are at higher risk for STD or HIV infection are more likely than other young men to get information about disease prevention, young adult men are much less likely than adolescents to receive AIDS or STD prevention education. More prevention efforts need to be aimed at young adults.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Sliding-scale premium health insurance programs: four states' experiences.

As publicly funded health insurance shifts more toward coverage of working families of low and moderate incomes, there has been growing interest in beneficiary cost sharing, in the form of sliding-scale premiums. In the 1990s, Hawaii, Minnesota, Tennessee, and Washington initiated expansion programs that used sliding-scale premiums for working-class families. The experience in these states indicates that it is feasible to require cost sharing of premiums, but there are a number of design and operational complexities. A preliminary analysis indicates that, as expected, higher out-of-pocket premium shares were associated with lower participation rates.

Cost Sharing↗