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Biomedical subjects

J A Preston

Publications and source records attributed to J A Preston.

7 recordsLinked to original sources
PubMed1997

Mammography underutilization among older women in Connecticut.

OBJECTIVES: The primary goals were to examine mammography use rates among older women in Connecticut and to determine if there was significant variation among different areas and racial groups in the state. The secondary goal was to examine what impact the initiation of Medicare reimbursement for mammography screening has had on mammography use. DESIGN: Statewide use rates were determined by retrospective Medicare Part B mammography claims analysis. Small area analysis methodology (SAA) was used to identify mammography rates for 23 hospital service areas (HSAs), representing all of the catchment areas for Connecticut's acute care hospitals. PARTICIPANTS: Female Medicare beneficiaries 65 years and older with Part B coverage residing in Connecticut during the study period. MEASUREMENTS: The main outcome (the use of at least one mammogram) was calculated for the calendar years 1991, 1992, and 1993. Mean annual use rates in 1993 were generated for the 23 HSAs and the different racial groups in Connecticut. To examine the effect that Medicare reimbursement for screening mammograms has had on mammography use, rates were calculated for women who met Medicare reimbursement criteria in 1991 through 1993. The rates in 1992 and 1993 were then compared with those in 1991, when the reimbursement program was first initiated. MAIN RESULTS: The mean statewide annual rates among women aged 65 years and older were 23.4% (1991), 24.5% (1992), and 24.9% (1993). The mammography use rates among black women 65 years and older were significantly lower than their white peers in 1991 (18.8% black vs 23.8% white, P < .001), 1992 (20.6% vs 24.7%, P < .001), and 1993 (22.0% vs 25.1%, P < .001). Significant variation was identified among hospital service areas (HSAs) within the state for each time interval studied. The use rates among women aged 65 years and older who were eligible for Medicare screening mammography reimbursement increased significantly from 14.6% in 1991, when Medicare reimbursement for screening mammograms was first initiated, to 18.9% in 1992 (P < .001). The rates in 1993 (17.4%) also increased from the baseline year 1991 (P < .001). However, the observed increases since 1991 have been limited in magnitude. CONCLUSIONS: Low mammography use persists among older women in Connecticut and, in particular, among older black women. The initiation of Medicare reimbursement for screening mammograms in 1991 has had some impact on mammography use although its effects are still limited. Through the use of small area analysis methodology, significant underutilization of mammography in localized areas of the state was identified. These findings have facilitated local outreach interventions. Additional research is needed to understand if health service barriers are contributing to the local variation in rates observed in this study.

Black or African American↗
PubMed1997

The human V3 pituitary vasopressin receptor: ligand binding profile and density-dependent signaling pathways.

The vasopressin (AVP) V3 pituitary receptor (V3R) is a G protein-coupled corticotropic phenotypic marker that is overexpressed in ACTH-hypersecreting tumors. Studies of the agonist/antagonist binding profile and signal transduction pathways linked to the human V3R have been limited because of the scarcity of this protein. To define the signals activated by V3Rs and the eventual changes triggered by developmental or pathological receptor regulation, we developed Chinese hamster ovary (CHO)-V3 cells stably expressing low, medium, or high levels of human V3Rs (binding capacity, <10, 10-25, and 25-100 pmol/mg, respectively). The affinity of the V3R for 21 peptide and nonpeptide AVP analogs was clearly distinct from that exhibited by the human V1R and V2R. AVP triggered stimulation of phospholipase C in CHO-V3 cells (partially sensitive to treatment with pertussis toxin) with a potency directly proportional to receptor density. V3R-mediated arachidonic acid release also was also sensitive to pertussis toxin and more efficacious in cells exhibiting medium than in those with high receptor density. AVP also stimulated the pertussis toxin-insensitive uptake of [3H]thymidine in CHO-V3 cells. The concentration-response curves for this effect were monophasic in cells expressing low and medium levels of V3Rs; on the contrary, a biphasic curve was observed in cells with high V3R density. Coupling of V3R to increased production of cAMP was only observed in CHOV3 high cells, suggesting a negative relationship between increased cAMP production and DNA synthesis. Activation of mitogen-activated protein kinases by V3R was pertussis toxin insensitive, but was dependent on activation of phospholipase C and protein kinase C; both the level and duration of activation were a function of the receptor density. Thus, the human V3R has a pharmacological profile clearly distinct from that of the human V1R and V2R and activates several signaling pathways via different G proteins, depending on the level of receptor expression. The increased synthesis of DNA and cAMP levels observed in cells expressing medium and high levels of V3Rs, respectively, may represent important events in the tumorigenesis of corticotroph cells.

Animals↗
PubMed1991

The management of geriatric hypertension in health maintenance organizations.

OBJECTIVE: To evaluate the quality of medical care received by Medicare enrollees with hypertension in health maintenance organizations (HMOs) compared to that received by a similar group of elderly hypertensives in a fee-for-service (FFS) setting. DESIGN: A quasi-experimental design was used to study an historical cohort of newly evaluated hypertensive patients over a 2-year period. SETTING: Medicare HMO and FFS practice settings. PARTICIPANTS: Eight Medicare HMOs and 87 FFS primary care physicians in the same communities were selected. A sample of 685 elderly hypertensive patients was studied, 336 in FFS settings and 349 in HMOs. MEASUREMENTS AND MAIN RESULTS: An expert panel of physicians selected standards of care for the management of geriatric hypertension, and medical records were reviewed. The results showed significant differences (P less than 0.01) in recording medications (94.5% HMO versus 88% FFS) and smoking histories (75.8% HMO versus 64.7% FFS), checking orthostatic blood pressures (9.5% HMO versus 3.3% FFS), performing funduscopy (44.4% HMO versus 27% FFS), completing cardiac examinations (90.8% HMO versus 79.8% FFS), and obtaining chest x-rays (72.8% HMO versus 64.3% FFS, P less than 0.05). Treatment and follow-up were similar between the two groups, except that FFS hypertensives were more likely to have medications adjusted and electrolytes ordered. CONCLUSIONS: The results suggest that elderly hypertensives in HMOs received equal or better quality of care for most criteria compared to elderly hypertensives in FFS settings.

Aged↗