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Biomedical subjects

M Komaromy

Publications and source records attributed to M Komaromy.

At least 19 recordsLinked to original sources
PubMed1999

Patient-physician racial concordance and the perceived quality and use of health care.

BACKGROUND: Patients from racial and ethnic minority groups use fewer health care services and are less satisfied with their care than patients from the majority white population. These disparities may be attributable in part to racial or cultural differences between patients and their physicians. OBJECTIVE: To determine whether racial concordance between patients and physicians affects patients' satisfaction with and use of health care. METHODS: We analyzed data from the 1994 Commonwealth Fund's Minority Health Survey, a nationwide, telephone survey of noninstitutionalized adults. For the 2201 white, black, and Hispanic respondents who reported having a regular physician, we examined the association between patient-physician racial concordance and patients' ratings of their physicians, satisfaction with health care, reported receipt of preventive care, and reported receipt of needed medical care. RESULTS: Black respondents with black physicians were more likely than those with nonblack physicians to rate their physicians as excellent (adjusted odds ratio [OR], 2.40; 95% confidence interval [CI], 1.55-3.72) and to report receiving preventive care (adjusted OR, 1.74; 95% CI, 1.01-2.98) and all needed medical care (adjusted OR, 2.94; 95% CI, 1.10-7.87) during the previous year. Hispanics with Hispanic physicians were more likely than those with non-Hispanic physicians to be very satisfied with their health care overall (adjusted OR, 1.74; 95% CI, 1.01-2.99). CONCLUSIONS: Our findings confirm the importance of racial and cultural factors in the patient-physician relationship and reaffirm the role of black and Hispanic physicians in caring for black and Hispanic patients. Improving cultural competence among physicians may enhance the quality of health care for minority populations. In the meantime, by reducing the number of underrepresented minorities entering the US physician workforce, the reversal of affirmative action policies may adversely affect the delivery of health care to black and Hispanic Americans.

Adult↗
PubMed1998

Unmet mental health needs of women in public-sector gynecologic clinics.

OBJECTIVE: We examined the mental health needs of poor young women seen in public-sector gynecologic settings. STUDY DESIGN: Participants were 205 ethnically diverse women, mean age 29 years, seen by gynecologists at San Francisco General Hospital, all either uninsured or receiving public medical assistance. An interview with an instrument designed to diagnose mood, anxiety, alcohol, and eating disorders in medical patients, the Prime-MD, was used to assess current mental disorders. Any history of sexual or other physical assault was recorded. Receipt of primary care was scored for comprehensiveness. RESULTS: The rates of current psychiatric disorders were extremely high; 21.5% had current major depression. The prevalence of anxiety disorders was also elevated among these women. Many had a history of sexual trauma, and 28% had been the victims of unwanted intercourse. Finally, many reported behaviors that pose serious health risks. For example, 32% smoked and 2% used illicit drugs. Fewer than half had access to comprehensive primary medical care. CONCLUSIONS: Young, poor women who seek care in public-sector gynecologic clinics would benefit from comprehensive medical care addressing their psychosocial needs.

Adult↗
PubMed1998

Accelerated lipoprotein uptake by transplantable hepatomas that express hepatic lipase.

To test the hypothesis that hepatic lipase plays a key role in lipoprotein removal in vivo, a novel system was used. Hepatoma cells (HTC 7288c) were transfected with a cDNA encoding hepatic lipase in culture and grown as solid tumors in vivo. In culture, transfected cells degraded chylomicron remnants and low density lipoprotein (LDL) somewhat more efficiently than untransfected cells. Tumors from the transplanted cells produced hepatic lipase localized to the surface of tumors from transfected cells but not tumors from non-transfected cells, grown in the same rat. The tumors from transfected cells removed, per gm of tissue, 34% (P < 0.001) more 125I-labeled LDL than tumors from non-transfected cells in the same animal. The uptake of chylomicron remnants (by tumors from transfected cells) was also modestly enhanced (15 +/- 6%, P < 0.005). There were no differences in the uptake of 125I-labeled albumin or 125I-labeled asialoglycoprotein. Compared to the liver, the untransfected tumors took up 12%, and the transfected tumors took up about 18% as much LDL per gram of tissue. The uptake of chylomicron remnants compared to liver was far lower. Both types of tumors had about twice as much LDL receptor related protein as the liver. Wild-type tumors had the highest level of LDL receptor, twice hepatic lipase-secreting tumors, and six times that of the liver. Using the novel approach of transfecting transplantable tumor cells with hepatic lipase, the ability of hepatic lipase to facilitate the removal of apoB-containing lipoproteins was demonstrated. The liver still removes low density lipoprotein and especially chylomicron remnants more rapidly than the tumors, suggesting factors in addition to hepatic lipase and LDL receptor level play a major role in hepatic lipoprotein removal.

Animals↗
PubMed1997

Primary care and patient perceptions of access to care.

BACKGROUND: Although much is known about how insurance affects access to care, it is unclear whether good primary care contributes to access. The purpose of this study was to determine how optimal primary care given by providers at a regular place of care, defined in terms of continuity, comprehensiveness, communication, and availability, contributed to perceptions of access to care in a large population-based probability sample of adults. METHODS: Data were from a cross-sectional survey of 6674 English- and Spanish-speaking adults 18 to 64 years of age, randomly sampled from 41 urban California communities with a range of levels of access to care. RESULTS: Following adjustment for sociodemographics and need for care, we found that having "optimal" primary care contributed independently to improved self-rated access, as did having health insurance, a regular place, and a regular provider. The largest difference n access was between having any health insurance and not having insurance. Once insurance was available, each additional element contributed in a cumulative manner to self-rated access. For those with insurance and a regular place, adding optimal primary care improved self-rated access to an extent similar to adding a regular provider. CONCLUSIONS: We conclude that although providing insurance to the uninsured is the most effective means of improving self-rated access, the other elements each improve access as well. Once insurance and a regular place are provided, good primary care at that place may be equivalent to having a regular provider in terms of perceived access. Results support promotion of primary care as a model of health care that encourages good access.

Adolescent↗
PubMed1996

Chinese hamster ovary cells expressing a cell surface-anchored form of hepatic lipase. Characterization of low density lipoprotein and chylomicron remnant uptake and selective uptake of high density lipoprotein-cholesteryl ester.

The enzyme hepatic lipase may play several roles in lipoprotein metabolism. Recent investigation has suggested a role for the enzyme in lipoprotein and/or lipoprotein lipid uptake. To study this, a simple isolated system that mimics the in vivo system would be desirable. The enzyme is secreted by the hepatic parenchymal cell but exists, and presumably exerts its effects, while bound to capillary endothelial cells in the liver, adrenal gland, and the ovary. We constructed a cDNA that encodes the expression of a chimeric protein composed of rat hepatic lipase and the signal sequence for the addition of the glycophosphatidylinositol (GPI) anchor from human decay-accelerating factor. When transfected into Chinese hamster ovary (CHO) cells this gave rise to a cell population that had immunoreactive hepatic lipase on the cell surface. Cloning of the transfected cells produced several cell lines that expressed the chimeric protein bound to the cell surface by a GPI anchor. This was documented by demonstrating incorporation of [3H]ethanolamine into anti-hepatic lipase immunoprecipitable material; in addition, hepatic lipase was released from the cells by phosphatidylinositol-specific phospholipase C but not by heparin. Phosphatidylinositol-phospholipase C treatment of cells expressing the anchored lipase released material that comigrated with hepatic lipase on SDS-polyacrylamide gel electrophoresis and was immunoreactive with antibody to the cross-reacting determinant of GPI anchors. Cell lysates containing the anchored protein contained salt-resistant lipase activity, a known feature of the secreted hepatic lipase; thus it appears that these cells have a surface-anchored hepatic lipase molecule. Although it was not possible to demonstrate lipolysis by the enzyme while it was on the cell surface for technical reasons, the protein produced by these cells was active when studied in cell membranes. The ability of the cells to take up lipoproteins was studied. The cells demonstrated an increased affinity for low density lipoprotein (LDL) receptor mediated uptake of LDL. They did not, however, demonstrate any enhanced binding or removal of chylomicron remnants. With respect to LDL and remnants, the cells expressing anchored lipase behaved similarly to CHO cell that expressed secreted hepatic lipase. The cells expressing anchored hepatic lipase had a marked increase in the uptake of high density lipoprotein and high density lipoprotein cholesteryl ester when compared to that seen with CHO cells secreting hepatic lipase. This increase occurred primarily via the selective pathway, and was not reduced by addition of anti-LDL receptor or anti-hepatic lipase antibodies or the receptor-associated protein. Together the results suggest that hepatic lipase, when bound to the cell surface by a GPI anchor, plays a role in enhancing lipoprotein uptake. For LDL this may involve the provision of a second foot for particle binding, thus enhancing affinity for the LDL receptor. For chylomicron remnants an additional molecule or molecules are necessary to mediate this effect. For HDL, the enzyme facilitates uptake of cholesteryl ester primarily by the selective pathway.

Amino Acid Sequence↗
PubMed1996

The role of black and Hispanic physicians in providing health care for underserved populations.

BACKGROUND: Patients who are members of minority groups may be more likely than others to consult physicians of the same race or ethnic group, but little is known about the relation between patients' race or ethnic group and the supply of physicians or the likelihood that minority-group physicians will care for poor or black and Hispanic patients. METHODS: We analyzed data on physicians' practice locations and the racial and ethnic makeup and socioeconomic status of communities in California in 1990. We also surveyed 718 primary care physicians from 51 California communities in 1993 to examine the relation between the physicians' race or ethnic group and the characteristics of the patients they served. RESULTS: Communities with high proportions of black and Hispanic residents were four times as likely as others to have a shortage of physicians, regardless of community income. Black physicians practiced in areas where the percentage of black residents was nearly five times as high, on average, as in areas where other physicians practiced. Hispanic physicians practiced in areas where the percentage of Hispanic residents was twice as high as in areas where other physicians practiced. After we controlled for the racial and ethnic makeup of the community, black physicians cared for significantly more black patients (absolute difference, 25 percentage points; P < 0.001) and Hispanic physicians for significantly more Hispanic patients (absolute difference, 21 percentage points; P < 0.001) than did other physicians. Black physicians cared for more patients covered by Medicaid (P = 0.001) and Hispanic physicians for more uninsured patients (P = 0.03) than did other physicians. CONCLUSIONS: Black and Hispanic physicians have a unique and important role in caring for poor, black, and Hispanic patients in California. Dismantling affirmative-action programs as is currently proposed, may threaten health care for both poor people and members of minority groups.

Black or African American↗
PubMed1996

Physician practice style and rates of hospitalization for chronic medical conditions.

Hospitalization rates for chronic medical conditions vary across small areas and are associated inversely with community income. The authors studied whether variation in hospitalization rates can be attributed to differences in physician practice style. Using census and hospital discharge data, hospitalization rates were calculated for asthma, congestive heart failure, and diabetes in 40 medical service areas in California. The authors surveyed a random sample of 1,530 emergency physicians, general internists, and family and general practitioners in these areas, and measured clinical admission threshold by asking physicians whether they would hospitalize patients presented in 15 vignettes of graded severity. The authors measured social admission predisposition by asking how physicians' admission decisions would be influenced by social characteristics that increase patients' vulnerability to illness, including homelessness and drug use; 1,090 physicians responded (71%). There was significant variation across areas in both the clinical (P < 0.0001) and social (P < 0.001) admission scores. Variation in hospitalization rates correlated with physicians' clinical (r = .34, P = 0.03) and social (r = .36, P = 0.02) admission scores. However, in a multiple linear regression analysis that included community sociodemographic factors, physician practice style was not associated significantly with hospitalization rates. Physician practice style varies across areas, but does not explain variation in admission rates for chronic medical conditions after adjusting for community sociodemographic factors. Using methods such as practice guidelines or utilization review to re-set physicians' threshold for admission may not be effective in reducing hospitalizations for chronic medical conditions.

Adult↗
PubMed1996

Relative roles of the LDL receptor, the LDL receptor-like protein, and hepatic lipase in chylomicron remnant removal by the liver.

Studies were carried out in mice utilizing inhibitors of several cell surface molecules to evaluate their relative roles in chylomicron remnant removal. Anti-LDL receptor antibody inhibited approximately 45% of rapid remnant removal from plasma, prolonged their half life (63 s to 115 s) and reduced hepatic uptake by 45%. Receptor-associated protein (RAP) (1 mg/mouse), a high affinity inhibitor of the LDL receptor-related protein (LRP) and a low affinity inhibitor of the LDL receptor decreased remnant removal approximately 55%, prolonged the half life from 63 s to 230 s, and reduced hepatic uptake by 70%. RAP, but not anti-LDL receptor antibody, inhibited splenic uptake. With both injected together, an incremental effect was seen; plasma removal decreased 60%, T1/2 increased to 290 s, and hepatic uptake decreased by 80%. Thus, it is likely that virtually all of the very rapid removal of remnants from the plasma by the liver requires the presence of at least one of these members of the LDL receptor family. Anti-hepatic lipase antibody caused a small but significant delay in remnant removal from plasma and a larger decrease in hepatic uptake (22.5%). It doubled adrenal uptake. The anti-hepatic lipase antibody was not additive with either the anti-LDL receptor antibody or RAP. Anti-rat hepatic lipase antibody did not inhibit lipolysis by mouse hepatic lipase, suggesting that lipolysis is not the way hepatic lipase enhances remnant uptake. Hepatic lipase bound to remnants to a greater degree than it bound to other lipoproteins. Together these data suggest that hepatic lipase may serve as a binding site for chylomicron remnants, thereby enhancing their affinity for the liver surface, and thus removal by the proteins of the LDL receptor family. Other molecules may also play a role in removal from the circulation under conditions where the LDL receptor family receptors are absent or occupied.

Animals↗
PubMed1995

Preventable hospitalizations and access to health care.

OBJECTIVE: To examine whether the higher hospital admission rates for chronic medical conditions such as asthma, hypertension, congestive heart failure, chronic obstructive pulmonary disease, and diabetes in low-income communities resulted from community differences in access to care, prevalence of the diseases, propensity to seek care, or physician admitting style. DESIGN: Analysis of California hospital discharge data. We calculated the hospitalization rates for these five chronic conditions for the 250 ZIP code clusters that define urban California. We performed a random-digit telephone survey among adults residing in a random sample of 41 of these urban ZIP code clusters stratified by admission rates and a mailed survey of generalist and emergency physicians who practiced in the same 41 areas. SETTING: Community based. PARTICIPANTS: A total of 6674 English- and Spanish-speaking adults aged 18 through 64 years residing in the 41 areas were asked about their access to care, their chronic medical conditions, and their propensity to seek health care. Physician admitting style was measured with written clinical vignettes among 723 generalist and emergency physicians practicing in the same communities. MAIN OUTCOME MEASURES: We compared respondents' reports of access to medical care in an area with the area's cumulative admission rate for these five chronic conditions. We then tested whether access to medical care remained independently associated with preventable hospitalization rates after controlling for the prevalence of the conditions, health care seeking, and physician practice style. RESULTS: Access to care was inversely associated with the hospitalization rates for the five chronic medical conditions (R2 = 0.50; P < .001). In a multivariate analysis that included a measure of access, the prevalence of conditions, health care seeking, and physician practice style to predict cumulative hospitalization rates for chronic medical conditions, both self-rated access to care (P < .002) and the prevalence of the conditions (P < .03) remained independent predictors. CONCLUSION: Communities where people perceive poor access to medical care have higher rates of hospitalization for chronic diseases. Improving access to care is more likely than changing patients' propensity to seek health care or eliminating variation in physician practice style to reduce hospitalization rates for chronic conditions.

Adult↗
PubMed1995

Site-directed mutagenesis using thermostable enzymes.

The two-primer method for site-directed mutagenesis facilitates the mutation of targets in double-stranded DNA. We have encountered difficulties using the original method for the mutagenesis of DNA cloned into pBluescript vectors, which is possibly due to the presence of regions of secondary structure that cannot be efficiently copied by the enzymes used. We report a modification of the two-primer method using the thermostable VentR DNA polymerase and Thermus aquaticus ligase, allowing an increase in reaction temperatures. The modified method is functional with the pBluescript family of vectors.

Base Sequence↗
PubMed1995

California physicians' willingness to care for the poor.

Although generalist physicians appear to be more likely than specialists to provide care for poor adult patients, they may still perceive financial and nonfinancial barriers to caring for these patients. We studied generalist physicians' attitudes toward caring for poor patients using focus groups and used the results to design a survey that tested the generalizability of the focus group findings. The focus groups included a total of 24 physicians in 4 California communities; the survey was administered to a random sample of 177 California general internists, family physicians, and general practitioners. The response rate was 70%. Of respondents, 77% accepted new patients with private insurance; 31% accepted new Medicaid patients, and 43% accepted new uninsured patients. Nonwhite physicians were more likely to care for uninsured and Medicaid patients than were white physicians. In addition to reimbursement, nonfinancial factors played an important role in physicians' decisions not to care for Medicaid or uninsured patients. The perception of an increased risk of being sued was cited by 57% of physicians as important in the decision not to care for Medicaid patients and by 49% for uninsured patients. Patient characteristics such as psychosocial problems, being ungrateful for care, and noncompliance were also important. Poor reimbursement was cited by 88% of physicians as an important reason not to care for Medicaid patients and by 77% for uninsured patients. Policy changes such as universal health insurance coverage and increasing the supply of generalist physicians may not adequately improve access to care unless accompanied by changes that address generalist physicians' financial and nonfinancial concerns about providing care for poor patients.

Adult↗
PubMed1993

Sexual harassment in medical training.

BACKGROUND: Sexual harassment has become a national concern and one that is increasingly recognized in the field of medicine. Although there are reports of the sexual harassment of medical trainees, there is little information on the prevalence of this problem and whether it is adequately addressed by training institutions. METHODS: Surveys with descriptions and examples of sexual harassment were mailed to 133 internal medicine residents in a university training program. The residents were asked to report anonymously whether they had encountered sexual harassment during medical school or residency, the frequency and type of harassment, its effect on them, whether they chose to report it to a person in authority, and the factors that influenced this decision. RESULTS: Surveys were returned by 82 residents (response rate, 62 percent), 33 women and 49 men. Twenty-four women (73 percent) and 11 men (22 percent) reported that they had been sexually harassed at least once during their training. The women were more likely than the men to have been physically harassed, and the women's harassers were of higher professional status. Among those harassed, 19 of the women (79 percent) and 5 of the men (45 percent) thought that the experience created a hostile environment or interfered with their performance at work, but only 2 women and no men reported their experiences to an authority. The women cited a lack of confidence that they would be helped as the main reason for not reporting the experience, whereas men most commonly said that they had dealt with the problem without the need for outside assistance. CONCLUSIONS: Many medical trainees encounter what they believe to be sexual harassment during medical school or residency, and this often creates a hostile learning and work environment. Training institutions need to address the adverse effects this may have on medical education and patient care.

Female↗
PubMed1993

Early induction of LDL receptor gene during rat liver regeneration.

After partial hepatectomy in the rat, there is substantial lipid accumulation in the liver. No information is available on the possible role of receptor-mediated endocytosis in this process. Since the low density lipoprotein (LDL) receptor is stimulated as a part of an early growth response in cell culture (Ellsworth et al.: Biochem. J. 279:175-187, 1991), the metabolism of this receptor during liver regeneration was studied. The mRNA and membrane protein level of the receptor were measured in the liver and in the adrenal glands at different times after partial hepatectomy, corresponding to different phases of the cell cycle. A discontinuous pattern of receptor expression is detectable in the regenerating liver; a large increase of mRNA and membrane protein occurs at an early time (2-4 h), suggesting that there is induction of LDL receptor gene transcription shortly after partial hepatectomy. This response seems specific for the liver following injury since the adrenal receptor does not show a different pattern in partially hepatectomized rats and sham-operated controls. After returning to control levels, the LDL receptor again increases slightly above control at 24 h, a time when cell replication begins.

Adrenal Glands↗
PubMed1989

Hepatic lipase in the rat ovary. Ovaries cannot synthesize hepatic lipase but accumulate it from the circulation.

Hepatic lipase is proposed to have a role in steroidogenesis through its involvement in the metabolism of high density lipoproteins. We examined the activity, synthesis, distribution, and uptake of this enzyme and assessed the content of its mRNA in luteinized ovaries. We found that during peak steroidogenesis, ovaries of pregnant mare's serum gonadotropin-human chorionic gonadotropin-treated immature rats contained heparin-releasable hepatic lipase-like activity which was neutralized in a dose-dependent manner by purified antibodies to hepatic lipase isolated from post-heparin perfusates of rat livers. Quantitative immunoelectron microscopy revealed that ovarian hepatic lipase occurred along endothelial cells and was 3-fold more abundant in blood vessels of corpora lutea than those of stroma. However, hepatic lipase was not synthesized by the ovary since radiolabeled enzyme was not immunoisolated from the medium of dispersed luteinized granulosa cells incubated with [35S]methionine whereas it was present in the medium of control cells (hepatocytes). Similarly, hepatic lipase mRNA was detectable in liver but not ovaries or kidneys by Northern or slot blot analyses or by the polymerase chain reaction. Finally, 125I-labeled hepatic lipase injected into tail veins was quickly cleared from the systemic circulation, accumulating in liver, ovaries, kidneys, and spleen. Subsequent heparin injection caused rapid reappearance of radioactivity in the bloodstream and a marked decline of radiolabel in liver and ovaries but a modest decrease of that in kidneys and none in spleen. Exogenous 125I-bovine serum albumin also accumulated in all four organs but was not displaced from liver or ovaries by subsequent administration of heparin. Taken together, these data suggest that steroidogenically active ovaries possess but do not synthesize hepatic lipase. Instead, hepatic lipase originating elsewhere, presumably in the liver, is accumulated from the circulation at heparin-sensitive sites in ovarian blood vessels.

Animals↗
PubMed1984

Analysis of membrane and surface protein sequences with the hydrophobic moment plot.

An algorithm has been developed which identifies alpha-helices involved in the interactions of membrane proteins with lipid bilayers and which distinguishes them from helices in soluble proteins. The membrane-associated helices are then classified with the aid of the hydrophobic moment plot, on which the hydrophobic moment of each helix is plotted as a function of its hydrophobicity. The magnitude of hydrophobic moment measures the amphiphilicity of the helix (and hence its tendency to seek a surface between hydrophobic and hydrophilic phases), and the hydrophobicity measures its affinity for the membrane interior. Segments of membrane proteins in alpha-helices tend to fall in one of three regions of a hydrophobic moment plot: (1) monomeric transmembrane anchors (class I HLA transmembrane sequences) lie in the region of highest hydrophobicity and smallest hydrophobic moment; (2) helices presumed to be paired (such as the transmembrane M segments of surface immunoglobulins) and helices which are bundled together in membranes (such as bacteriorhodopsin) fall in the adjacent region with higher hydrophobic moment and smaller hydrophobicity; and (3) helices from surface-seeking proteins (such as melittin) fall in the region with still higher hydrophobic moment. alpha-Helices from globular proteins mainly fall in a region of lower mean hydrophobicity and hydrophobic moment. Application of these methods to the sequence of diphtheria toxin suggests four transmembrane helices and a surface-seeking helix in fragment B, the moiety known to have transmembrane function.

Amino Acid Sequence↗
PubMed1984

An inexpensive semi-automated sequence reader for the Apple II computer.

We describe a relatively inexpensive digitizing pad, available from Houston Instruments, for which we have written software which allows the direct reading of DNA (or RNA) sequencing gel autoradiographs. This eliminates several sources of error in nucleic acid sequencing, and renders computer analysis less cumbersome.

Autoradiography↗
PubMed1983

The structure of the mouse immunoglobulin in gamma 3 membrane gene segment.

The genomic region containing the mouse immunoglobulin gamma 3 heavy chain membrane (M) exons has been located and sequenced. The exon structure is highly similar to that of the other mouse gamma chains, with strong sequence conservation in the coding regions and the intron 5' to the M1 exon. The intron between M1 and M2 shows moderate sequence homology but very strong conservation of size. RNA blots suggest that gamma 3 membrane exon usage is similar to that seen in other immunoglobulin membrane heavy chain mRNAs. The transmembrane region contains the invariant residues which have been noted in all other heavy chain sequences and which were previously proposed to be interactive in a two-chain model for insertion through the lymphocyte membrane. Conserved residues with similar spacing have been seen in class II histocompatibility antigens, which are also two-chain transmembrane molecules, but not in class I antigens, which span cell membranes with a single chain.

Amino Acid Sequence↗