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Biomedical subjects

M Ahern

Publications and source records attributed to M Ahern.

At least 37 records · Page 2Linked to original sources
PubMed1996

Inpatient utilization by undocumented immigrants without insurance.

Data collected from a large county hospital in Miami, Florida were used to study the severity of illness (using the Case Mix Severity Index) and resource use (measured by average length of stay, procedures, and/or diagnostic tests performed) of undocumented persons from Dade Country, Florida in an inpatient setting. Compared with native-born populations and those with permanent residency status (insured by Medicaid or of uninsured status) admitted to the same hospital, undocumented immigrants had a higher Case Mix Severity Index but a lower adjusted average length of stay. Undocumented immigrants and uninsured residents of the United States had a similar number of adjusted procedures/ tests performed, but less than Medicaid beneficiaries. Policy issues are discussed.

Adult↗
PubMed1995

Iron overload facilitates hepatic fibrosis in the rat alcohol/low-dose carbon tetrachloride model.

The role of iron deposition in initiating hepatic fibrosis in iron overload disorders is not clearly established, and it is becoming increasingly recognized that iron may be interacting with other potential liver-damaging agents. The authors therefore examined the interplay of iron and alcohol in rats administered subtoxic doses of carbon tetrachloride (CCl4) vapor at 20 ppm in customized chambers. At birth, the offspring of seven pregnant Porton rats were divided into two groups: one group was fed a normal rat chow diet and the other a diet supplemented with 3% (w/w) carbonyl iron for 10 weeks after weaning. In this latter group, the mothers were fed an iron supplement while breastfeeding. At 10 weeks, the animals from the first group (normal chow) were divided into two groups of six animals and fed a Lieber-DeCarli liquid diet with daily exposure to CCl4 vapor: group 1, liquid diet+CCl4; group 2, liquid diet+alcohol 150 kcal/l+CCl4. The animals from the second iron-supplemented group were divided into two groups of six animals and fed a liquid diet with 3% (w/v) carbonyl iron and exposed to CCl4 vapor for 10 weeks: group 3, liquid diet+iron+CCl4; group 4, liquid diet+iron+alcohol supplement+CCl4. Two animals from each group of six had a liver biopsy at 4, 6, and 8 weeks, and all animals were killed after 10 weeks of CCl4 exposure. After the first 10-week iron loading period, the rats fed the carbonyl iron-supplemented diet had a 10-fold elevation in hepatic iron concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Age-related defects in CD2 receptor-induced activation in human T-cell subsets.

It is well documented that the proliferative capacity of T cells declines with advancing age. There are, however, conflicting data as to the role of the accessory cell and whether or not this loss in responsiveness extends to all T-cell stimuli and to all T cells. We report here on the capacity of subpopulations of peripheral blood CD4+ T cells from the healthy aged to proliferate in response to anti-CD2 receptor-induced activation in the complete absence of accessory cells by using various exogenous cofactors as second signals. These costimulatory factors included phorbol 12-myristate 13-acetate (PMA), interleukin (IL)-1, IL-2, IL-6 and IL-7 and the monoclonal antibodies, anti-CD28 and anti-CD44. Under these conditions, the proliferative responsiveness of CD4+CD45RO+ T cells from the aged was found to be comparable to young control cells for all stimuli tested, except anti-CD2 plus IL-7. This suggests that signal transduction pathways involving CD2, except IL-7-mediated events, are essentially intact in 'old' memory CD4+ T cells. On the other hand, several cofactors, namely IL-2, IL-6, IL-7 and to a lesser extent IL-1 beta and PMA, failed to support adequately CD2-induced activation in 'old' CD4+CD45RA+ T cells suggesting severe and multiple signalling deficiencies in this subset.

Aged↗
PubMed1995

Pulse methylprednisolone in rheumatoid arthritis: effects on peripheral blood and synovial fluid neutrophil surface phenotype.

OBJECTIVE: To determine the effects of a 1000 mg intravenous pulse of methylprednisolone (MP) on the expression of cell adhesion molecules on peripheral blood and synovial fluid (SF) neutrophils in rheumatoid arthritis. METHODS: Fluorescent flow cytometric analysis was performed on peripheral blood neutrophils (n = 13 patients) and knee joint SF neutrophils (n = 7 patients) prior and at 4 and 24 h after MP. Clinical and laboratory assessments of disease activity were performed. RESULTS: There was marked improvement in all clinical stores at 24 h including a decrease in pain score (p < 0.0005), stiffness (p < 0.00005), joint tenderness score and modified Health Assessment Questionnaire (HAQ) (p < 0.005), and an increase in well being (p < 0.001). At 24 h there was a significant decrease in SF neutrophil counts to mean (SEM) of 31.5% (15%) of baseline and an increase in peripheral blood neutrophils to a mean (SEM) of 199% (25%) of baseline. Furthermore, a significant decrease was observed in the expression of both structural and functional epitopes of CD11b (p < 0.05) and CD18 (p < 0.05) on SF neutrophils at both 4 and 24 h post-MP. There was also an increase in the expression of L-selectin (CD62L), which approached significance (p = 0.01), but no significant effect on CD11a, CD44 and sialyl Lewisx (CD15s). Peripheral blood neutrophils showed decreased expression of CD11b (p = 0.1), CD18 (p = 0.07), and L-selectin (p = 0.09), which approached statistical significance without any associated effects on CD11a, CD15s, or CD44. CONCLUSION: MP is associated with a marked decrease in CD11b and CD18 expression on SF neutrophils and, to a lesser extent, peripheral blood neutrophils. This may be due to decreased neutrophil activation as these cells traffic from the vasculature through the synovial membrane or to decreased activation in the synovial space.

Aged↗
PubMed1994

Differential expression and regulation of cytokine mRNAs in normal human CD45R T cell subsets.

Cytokine mRNA expression was analyzed by reverse transcriptase (RT)/PCR in extensively purified normal peripheral CD4+CD45R T cell subsets. Both CD45RA+ and CD45 RO+ populations produced mRNAs for interleukin (IL)-2, IL-2 receptor (alpha chain), IL-6 receptor and tumour necrosis factor (TNF)-beta within 3-4 h of activation. Whilst IL-3 and RANTES were also expressed in both subsets, CD45RO+ cells were clearly the major producers of these cytokines. In contrast, mRNA transcripts for IL-1 alpha, IL-4, IL-5, IL-6, IL-10, interferon gamma (IFN-gamma) and the T cell receptor for IL-1 were almost exclusively induced in CD45RO+ T cells. A population of CD4+ T cells co-expressing intermediate levels of both CD45RA and CD45RO, namely CD45RA+/CD45RO+, appeared to be the major producers of IL-6. Addition of cycloheximide (CHx) 4 h after T cell activation resulted in substantial superinduction of IL-2 mRNA in the CD4+CD45RO+ population but had little effect on CD4+CD45RA+ cells. Taken together, these results show that normal CD4+CD45R T cell subsets exhibit distinct cytokine mRNA profiles and that these differ from the patterns displayed by Th1 and Th2 type T helper clones. Furthermore, they suggest for the first time that IL-2 mRNA turnover is differentially regulated in CD45R T cell subsets.

Adult↗
PubMed1994

Screening for genetic haemochromatosis in a rheumatology clinic.

BACKGROUND: Recent data indicate that the prevalence of genetic haemochromatosis (GH) is greater than previously recognised and suggest that this disease is underdiagnosed. AIMS: To determine the prevalence of GH in rheumatology clinic population. METHODS: Over a 12 month period 339 consecutive patients, mean age 67.0 years, attending a rheumatology clinic were screened for iron overload. RESULTS: Twenty three patients had elevated initial screening tests (transferrin saturation [Tf%] > 55%; ferritin > 500 micrograms/L). Repeat fasting Tf% and ferritin concentrations were obtained in 20 of these patients. Twelve patients had persistently elevated results, and of these patients four had liver biopsy tissue hepatic iron indices consistent with GH. One patient in the group had the diagnosis established by liver biopsy just before the screening commenced. Thus, the prevalence of GH in this population was 1.5%--five times that anticipated for the general population. Three of the patients with GH presented with an arthropathy which was not characteristic of the disease. The increased prevalence of GH in this group of patients with peripheral arthropathy provides an excellent justification for the routine screening of patients with peripheral arthritis for the exclusion of iron overload.

Aged↗
PubMed1994

Regional and individual differences in physician practices for joint-ventured versus non-joint-ventured physicians.

OBJECTIVE: This article compares characteristics of physicians who have invested in health care business (joint ventures) to characteristics of physicians who have not, based on a survey of Florida physicians. DATA SOURCES/STUDY SETTING: In early 1990, a survey was mailed to a stratified random sample of 1,000 Florida physicians. Half were randomly selected from lists of joint-ventured physicians who had been identified as owners in a previous study by the Florida Health Care Cost Containment Board. The remaining half were assumed to be non-joint-ventured (although incomplete results from the previous study meant that some of these physicians would be joint ventured as well). We tagged survey variables with additional variables from the same year representing exogenous influences. STUDY DESIGN: The survey was mailed to a stratified random sample of physicians across specialty and geographic area, with half to identified joint-ventured physicians and half to a control group, some of whom were expected to be joint-ventured. Thus, results regarding differences would be understated. Key variables include referring versus nonreferring physician, to shed light on motivation for joint-venturing; clientele served, to see if systematic differences had implications related to access for poor or underserved persons; geographic area, to see if joint-ventures were undertaken to increase access in rural areas; and other practice variables such as size and type of practice. DATA COLLECTION/EXTRACTION METHODS: Data from all received surveys were encoded and analyzed using SPSS. Incomplete surveys were also encoded so that all information would be available for possible use. PRINCIPAL FINDINGS: Results indicate that joint-ventured physicians are more likely than non-joint-ventured physicians to be referring physicians. Also, joint-ventured physicians report serving lower proportions of Medicaid and self-pay (uninsured) patients and higher proportions of Medicare patients. Joint-ventured physicians are also more likely to practice in urban areas, to practice full time, to be members of larger practices, and to practice in group practices. Further, joint-ventured physicians are more likely to practice in areas with high proportions of Medicare patients. CONCLUSIONS: Policymakers should continue to regard physician joint ventures as problematic, since results of this study indicate that physicians who engage in a joint venture almost always have the ability to refer patients to that joint venture due to the nature of their practices. Results also show that joint ventures are associated with decreased access: that is, they provide care to lower proportions of poor and underserved patients and rural patients than their non-joint ventured counterparts.

Economics, Medical↗
PubMed1994

Inclusion body myositis in association with rheumatoid arthritis.

We describe 2 patients with rheumatoid arthritis (RA) and inclusion body myositis (IBM). Examination and laboratory tests including muscle biopsy with frozen section and electron microscopy were performed. Both patients fulfilled diagnostic criteria for IBM, which is increasingly recognized in association with autoimmune disease. A high index of suspicion and early thorough investigation are required to diagnose IBM in patients with RA.

Aged↗
PubMed1993

A comprehensive analysis of peripheral blood lymphocytes in healthy aged humans by flow cytometry.

This study used a panel of mAb and multiparameter flow cytometry to assess the composition of PBL from healthy aged individuals. The results showed that while total lymphocyte numbers altered only marginally in the aged (> or = 70 years) there were significant changes in the distribution of various sub-populations; for example, there were lower numbers of CD3+ and CD8+ cells, and higher numbers of CD16+ (NK) cells. As a direct result of these changes the numbers of CD2+ cells remained unchanged in the aged compared with young adult controls (18-25 years). The number of CD4+ T cells expressing CD45RO isoform (memory cells) exceeded the number of CD4+CD45RA+ (naive) cells in aged donors, whereas the converse was true for young donors. In addition, associated with this increase in CD45RO+ cells, the aged showed an expanded population of CD45RO+ T cells displaying low surface levels of CD45RO. These data suggest that shifts in the distribution of regulatory T cell subsets may play a role in age-related changes in immune response.

Adolescent↗
PubMed1993

Effects of payment changes on urgent/emergent admissions in rural and urban communities.

Reimbursement changes during the 1980s, particularly Medicare diagnosis-related group (DRG) reform and the growth of managed care, have squeezed hospital revenues available for cross-subsidizing care for uninsured patients and patients for whom marginal costs exceed marginal revenues. This study uses logistic regression with time and residence interactions to explore the impact of payment changes on rural versus urban patients' admission status (urgent versus nonurgent). Findings show that uninsured rural patients had a significantly higher probability in 1987 than they did in 1983 of being admitted to hospitals in an urgent/emergent condition. Findings also show incrementally higher probabilities for Medicare and Medicaid rural patients in 1987. Results are consistent with the view that cross-subsidization is no longer effective for covering uninsured rural care and that more direct subsidies may be necessary.

California↗
PubMed1993

Survey of Florida physicians. Characteristics and satisfaction.

Data from a 1991 physician survey jointly sponsored by the Florida Medical Association and the Florida Physicians Association are used to assess characteristics and satisfaction of Florida physicians in the current environment of increased managed care initiatives. Significant predictors of HMO affiliation include an urban practice location, a low proportion of Medicare patients, and Hispanic ethnicity. Income is negatively associated with HMO-affiliation, although not significantly. Physicians affiliated with HMOs are less satisfied than their counterparts with respect to current and future earnings, skills enhancement opportunities, time with patients, patient appreciation, specialty referral systems, overall quality of practice, opportunity to practice in desired manner, and overall satisfaction. Other results showed that Florida's primary care physicians are less satisfied than other physicians across some components of their practices. Also, HMO-affiliated physicians who participate in managerial decision-making are significantly more satisfied than other physicians.

Adult↗
PubMed1992

Reducing older patients' reliance on the emergency department.

Older adults tend to avoid mental health services and rely on hospital emergency departments for medicalization of these conditions. An intervention was designed for use in emergency departments to refer older adult patients with mental and social health problems to appropriate services within the hospital and community. Most of the patients in the study used the services to which they were referred; further, the intervention was found to decrease repeat utilization of the emergency department. Social work practice and policy implications of the findings are also discussed.

Aged↗
PubMed1992

Age-related changes in the expression of T cell activation antigens following phytohaemagglutinin stimulation.

The role of accessory cells (AC) in the temporal expression of several key T-cell-activation-associated antigens has been studied in healthy aged subjects. Compared to responses seen in young adults, phytohaemagglutinin (PHA) induced weak proliferation in peripheral blood mononuclear cells from the aged and lower numbers of T cells expressing CD71, CD25, CD38 or HLA-DR. T cell responses to the monoclonal antibody OKT3, however, were normal. Whereas HLA-DR+ T cell numbers could be increased by raising the AC content (up to 50%) in cultures comprising purified T cells and graded numbers of autologous AC, CD25+ T cell numbers remained largely unaltered. Co-stimulation with PHA + phorbol myristate acetate in the absence of AC restored both proliferation and CD25 expression in the aged. These results indicate that T cells from the healthy aged show selective deficiencies in their capacity to respond to mitogenic stimuli and suggest that impaired PHA responsiveness is due, at least in part, to defective AC-derived signals.

Aged↗
PubMed1992

Emergency room admissions: changes during the financial tightening of the 1980s.

During the 1980s, as hospital payment systems constricted and the number of uninsured Americans grew, the configuration of admissions through the emergency room changed (measured through logit estimation using discharge data for California patients in 1983 and 1987). In particular, the probability that uninsured and minority patients were admitted through the emergency room increased between 1983 and 1987. In addition, between 1983 and 1987, the probability of admission through the emergency room for urgent/emergent medical conditions increased for uninsured patients and Medicaid patients, indicating that access for these groups has deteriorated during the period when payment systems have constricted.

Adolescent↗
PubMed1991

Age-related changes in the activation requirements of human CD4+ T-cell subsets.

In agreement with previous studies, we found that the proliferative response of unfractionated T-cells to phytohaemagglutinin (PHA) was severely impaired in healthy aged individuals (70-85 years). On the other hand, we did not observe significant differences between aged and young adults in T-cell responsiveness to mab OKT3 (anti-CD3). PHA responses in "old" T-cells could be substantially improved, however, by the addition of recombinant interleukin-2 (rIL-2) or KOLT2 (anti-CD28 mab). When individual CD4+ T-cell subpopulations were isolated from young and old donors and stimulated with PHA in the presence of autologous accessory cells, age-related deficiencies were seen in both CD4+CD45RA+ (naive) and CD4+CD45RO+ (memory) cell populations. Further analysis using a panel of coactivators in cultures depleted of accessory cells identified specific abnormalities in the CD2 or alternate pathway of T-cell activation. These were predominantly seen in CD4+ naive T-cells. The capacity of rIL-2, KOLT2, and PMA to restore, at least partially, T-cell responsiveness in the aged suggests a defect(s) in an early signal transduction mechanism.

Adult↗
PubMed1990

T cell activation in the elderly: evidence for specific deficiencies in T cell/accessory cell interactions.

We studied T cell activation in the healthy aged (greater than 70 years) by examining lymphocyte proliferative responses to various mitogenic stimuli in accessory cell (AC)-dependent and AC-independent systems. Results show that despite a near normal response to the anti-CD3 monoclonal antibody (mAb) OKT3, peripheral blood mononuclear cells (PBM) from the elderly exhibit a profound reduction in phytohaemagglutinin (PHA)-responsiveness (approximately 30% of young adults). This deficit becomes even more severe at suboptimal doses of PHA. Adding exogenous interleukin-2 (IL-2) or pretreating the AC population with gamma interferon (IFN-gamma) returns the level of proliferation to that seen with young adults. Furthermore, replacing "old" AC with AC from young adults or with U937 (a monocytic cell line) in T cell/AC cell-mixing experiments restores PHA-responsiveness in 70% of cases. On the other hand, AC from the aged fully support PHA responses in T cells from young adults. In AC-depleted cultures, purified T cells from the aged respond normally to the co-mitogenic stimuli, PHA + PMA. Taken together, these results suggest that the age-associated diminution in PHA-responsiveness is due, at least in part, to specific deficiencies in T cell/AC communication.

Aged↗
PubMed1988

Local radiotherapy for pedal manifestations of HLA-B27-related arthropathy.

Four males with characteristic foot manifestations of HLA-B27-related arthropathy are reported. The severity of this problem and its recalcitrance to standard therapies led to the use of local radiotherapy. The beneficial outcome and minimal short-term side effects of this treatment are discussed in relation to previous experience with radiotherapy in ankylosing spondylitis.

Adolescent↗