The use of mammography by women aged 75 and older: factors related to health, functioning, and age.

BACKGROUND AND OBJECTIVES: Mammographic screening for breast cancer is of uncertain clinical benefit for women 75 years of age and older. Some have argued against instituting routine screening in this age group, noting that disability and shorter life expectancy may diminish the desirability and cost-effectiveness of screening. We sought to determine the extent to which health, functioning, and age influence mammography use in this cohort. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study of a representative sample of women in the US aged 75 and older (n = 2352) who participated in the Medicare Current Beneficiary Survey. MEASURES: Information about general health, level of functioning, medical history, age, and various sociodemographic characteristics elicited in the survey was linked with subjects' Medicare bills for 1991 and 1992 to ascertain patterns of mammography use. RESULTS: Overall, 26.7% of the women had mammograms during the 2-year period. Advanced age was associated with a decreased likelihood of receiving a mammogram. This did not reflect simply the decline in health and functioning that may accompany aging; those aged 85 and older were less likely to receive mammograms than those in the 75 to 79 age group, controlling for general health, medical history, functional status, and sociodemographic factors (adjusted OR = .41; 95% CI = 0.27 to 0.64). ADL limitations were also associated independently with decreased mammography use. For example, controlling for age, women with any limitations in Activities of Daily Living were 0.71 times as likely to have mammograms as women without ADL limitations (95% CI = 0.59 to 0.85). However, several comorbid conditions, including hypertension, diabetes mellitus, and a history of myocardial infarction were not significantly related to mammography use. CONCLUSIONS: Within the cohort of women aged 75 and older, more advanced age and impaired functional status both substantially reduce the likelihood of mammography use. The extent to which this reflects patients' informed decisions, physicians' judgments, or other factors remains to be explored.

Visits to specialists under Medicare: socioeconomic advantage and access to care.

This study examines the relationship between socioeconomic advantage and the likelihood of receiving specialty care in a nationally representative sample of older Americans participating in fee-for-service Medicare. In 1992, 62.9 percent of Americans aged 65 and older visited a specialist physician at least once. Being white, having more education, and having a higher income were each independently associated with a higher likelihood of visiting a specialist. Having insurance to supplement basic Medicare coverage was also independently associated with an increased likelihood of visiting a specialist; disadvantaged elders are less likely to have such supplemental insurance. Therefore, based both upon socioeconomic disadvantage and a lack of insurance to supplement the basic Medicare benefit, black, less educated and low-income elders are less likely to receive specialty services under fee-for-service Medicare. As the program evolves, it will be important to continue to monitor access to specialty care in vulnerable, socioeconomically disadvantaged populations.

Faithful patients: the effect of long-term physician-patient relationships on the costs and use of health care by older Americans.

OBJECTIVES: This study examined the impact of duration of physician-patient ties on the processes and costs of medical care. METHODS: The analyses used a nationally representative sample of Americans 65 years old or older who participated in the Medicare Current Beneficiary Survey in 1991 and had a usual source of care. RESULTS: Older Americans have long-standing ties with their physicians; among those with a usual source of care, 35.8% had ties enduring 10 years or more. Longer ties were associated with a decreased likelihood of hospitalization and lower costs. Compared with patients with a tie of 1 year or less, patients with ties of 10 years or more incurred $316.78 less in Part B Medicare costs, after adjustment for key demographic and health characteristics. However, substantial impacts on the use of selected preventive care services and the adoption of certain healthy behaviors were not observed. CONCLUSIONS: This preliminary study suggests that long-standing physician-patient ties foster less expensive, less intensive medical care. Further studies are needed to confirm these findings and to understand how duration of tie influences the processes and outcomes of care.

Circulating growth factor studies in growth plate versus resting cartilage in vitro. II. Recognition of growth factors in rat serum.

The growth-promoting effects of GH can be explained in part by the mediation of somatomedins/insulin-like growth factors (IGFs). However, large quantities of the IGFs are required to stimulate growth in vivo, and in some conditions, IGF levels may correlate poorly with GH levels and growth status. These observations suggest that other circulating factors may also be important for growth. We have examined the growth-promoting activity in rat serum, as assessed by stimulation of sulfate and/or thymidine uptake by resting and growth plate cartilage (osteochondral junction) from hypophysectomized rats in vitro. Although stimulation by a low molecular weight somatomedin fraction (approximately 5,000-12,000) accounted for about 90% of serum stimulation of sulfate uptake by resting cartilage, it explained only about 60% of stimulation of the growth plate. Growth plate and resting cartilage appeared equally insensitive to insulin, but the growth plate exhibited reduced sensitivity to inhibitor(s) in diabetic rat serum. Fractionation of normal rat serum by gel filtration at neutral pH revealed comparable stimulation of growth plate and resting cartilage by high molecular weight factors, presumably somatomedins bound to carrier proteins. After gel filtration at acid pH, both growth plate and resting cartilage responded to somatomedins with molecular weights from 5,000-12,000. However, the growth plate also responded to a 12,000-22,000 mol wt factor [Sephadex G-75; 5 X 120 cm; sulfate uptake, 68 +/- 16% above buffer (mean +/- SEM); P less than 0.01] which did not affect resting cartilage (sulfate uptake, 27 +/- 21% above buffer; P = NS). Levels of both the low and higher molecular weight factors were reduced in the serum of hypophysectomized rats. We conclude that circulating growth-promoting activity includes both the low molecular weight somatomedins and a higher molecular weight growth plate growth factor which is not recognized by resting cartilage. Use of the osteochondral junction assay system may permit elucidation of the regulation and nature of this growth factor.

An alternative health delivery system for the chronically ill elderly.

The present health care system is fragmented, uncoordinated, and too costly for the chronically ill, elderly patient. Project OPEN provides preventive health and social services in order to reduce costs and provide more effective care. This alternative delivery system is based on a consortium brokerage model which provides functional assessment, care plan development and service coordination. A randomized sample of 338 elderly individuals participated in a time series experiment. Client functional status, service utilization, and all health costs were collected for six months. The results indicated a maintenance in functioning levels, a decrease in acute hospitalizations, and a 20% reduction in health care costs for the demonstration participants as compared to the control group. Project OPEN provided more effective care while simultaneously reducing health expenditures to the chronically ill elderly.

Circulating growth factor studies in growth plate versus resting cartilage in vitro: tissue responsiveness.

We attempted to develop a system in which cartilage growth-plate responses could be examined in vitro. In vivo, rat osteochondral growth-plate width was decreased by hypophysectomy and restored toward normal by GH. Subsequently, segments of resting costal cartilage and osteochondral growth plate from hypophysectomized rats were incubated in vitro with [35S]sulfate and [3H]thymidine. Within ribs, growth plate generally had basal uptake greater than resting cartilage and a greater increase in activity on addition of normal rat serum. Across ribs 3-9, there was little change in growth plate or resting cartilage sulfate uptake, and only a modest increase in thymidine uptake caudally. Increasing concentrations of normal rat serum provided parallel stimulation for both growth plate and resting cartilage, with significant responses to as little as 1 microliter (sulfate uptake) or 5 microliters (thymidine uptake). Stimulation for both growth plate and resting cartilage by hypophysectomized rat serum was significantly less than by normal rat serum; activity was restored by GH in vivo, establishing growth plate responsiveness to GH- and pituitary-dependent factors. Growth plate and resting cartilage were generally unaffected by exposure in vitro to supraphysiological concentrations of GH, cortisol, testosterone, estradiol, or T3. Use of osteochondral junction tissue appears to yield an assay system that is sensitive and sufficiently reproducible to allow study of growth factor action at the growth plate in vitro.

The thrombin-like enzyme from Bothrops atrox snake venom. Properties of the enzyme purified by affinity chromatography on p-aminobenzamidine-substituted agarose.

The trhombin-like activities from the snake venoms of two subspecies of Bothrops atrox, moojeni (type I) and marajoensis (type II), were purified to homogeneity by affinity chromatography on a support consisting of the inhibitor, p-aminobenzamidine, linked to Sepharose 4B with a spacer of diaminodipropylaminosuccinate. At room temperature the enzyme was not bound to the affinity support but rather was retarded in relation to the unbound protein. As a result the thrombin-like activity eluted in a large volume following the main protein fraction. However, at 4 degrees the enzyme was absorbed to the affinity support and could be eluted specifically with the ligand benzamidine (0.15 M). Optimal conditions for column loading and washing were 0.05 M Tris.HCl/0.4 M NaCl, pH 9.0 at 4 degrees. The type I enzyme isolated in this manner showed a single major band on pH 8.9 disc gel electrophoresis as well as two minor bands. Further purification by isoelectric focusing yielded one major and two minor components. All three protein fractions had identical thrombin-like activities and amino acid composition. The major band had a specific activity of 210 to 230 NIH thrombin units/mg, a S20, w of 2.65 S, a molecular weight of 29,000, and an E1% 280 of 15.6. This protein has a carbohydrate content, measured as hexose, glucosamine, and sialic acid, of 27%. From the amino acid and carbohydrate composition a partial specific volume of 0.700 ml/g was calculated. The type I enzyme, purified on affinity chromatography only, did not activate Factor XIII and was free of thromboplastin-like activity. The type II enzyme behaved very differently from the type I on pH 8.9 polyacrylamide disc gels yielding two major bands and two minor bands. The relative amounts of these four bands were not a function of purity. The type II enzyme had a specific activity of 650 to 700 NIH thrombin units/mg, a S20, w of 2.60, and a molecular weight of 31,400.

The primary structure of cytochrome c from the rust fungus Ustilago sphaerogena.

1. The complete amino acid sequence of cytochrome c from the basidiomycete Ustilago sphaerogena was determined from the amino acid compositions and sequences of either tryptic or chymotryptic peptides, and in homology with at least thirty other established sequences of cytochrome c. 2. The primary structure of the molecule bears all of the characteristics of a mammalian-type cytochrome c, showing the typical clustered distribution of hydrophobic and basic residues with a single polypeptide chain of 107 residues. 3. Like all other fungal cytochromes c, it possesses a free N-terminus, and one less residue at the C-terminus than vertebrate cytochromes c. The region of residues 70-80 is strictly conserved, as is histidine at position 18. Position 26 is occupied by an asparagine residue, in contrast to histidine which occurs at this location in most of the known sequences of mammalian-type cytochromes c. 4. In contrast to some other fungal and plant cytochromes c of known primary structures, the Ustilago cytochrome c molecule does not contain trimethyl-lysine. 5. The sequence of Ustilago cytochrome c differs from the sequences of human, horse, chicken, tuna, wheat, and baker's yeast proteins at loci 47, 43, 44, 44 and 38 respectively.