The effect of health insurance coverage on the appropriate use of recommended clinical preventive services.

INTRODUCTION: Lack of health insurance coverage has been shown to reduce use of some preventive services. However, even when care is free or fully covered by insurance, clinical preventive services are not used at recommended levels. This study investigates the impact of different levels of health insurance coverage (ranging from none, some, most, and all preventive services covered) on the use of recommended clinical preventive services for adult men and women. METHODS: Logistic regression was used to estimate the effect of different levels of health insurance coverage for preventive care on the probability of receiving six different clinical preventive services including periodic health exam, blood pressure screening, cholesterol screening, Pap smear, clinical breast exam, and screening mammography, as well as all recommended services for a given age and gender group. The study sample of adults ages 18 to 64 is from the Centers for Disease Control's 1991 Behavioral Risk Factor Surveillance System (BRFSS) (n = 53,981). RESULTS: The results demonstrate a positive and statistically significant dose-response relationship between level of health insurance coverage for preventive care and receipt of recommended preventive services in adult men and women. The odds ratios (ORs) of men who had full coverage for preventive care receiving recommended preventive services compared to men with no coverage for preventive care ranged from 1.8 to 2.8. For women the ORs were 1.2 to 2.0. The ORs for men with "most" preventive services covered compared to none covered ranged from 1.3 to 2.1, and for women from 1.2 to 2.0. CONCLUSIONS: The level of health insurance coverage for preventive care is one of the most important determinants of receipt of recommended preventive services for adult men and women 18-64 years of age. These results suggest that comprehensive health insurance coverage for clinical preventive care may significantly increase receipt of recommended preventive services for this population.

In vitro radiation survival parameters of human colon tumor cells.

As part of an ongoing research program in the biology of human colon cancer cells, a database is being generated on the radiation responses of established lines in vitro. In this report, data are summarized on the graded single dose clonogenic survival responses to graded single doses of 250 kVp X rays of 16 exponentially growing lines. These data were analyzed using the linear quadratic (LQ) formalism for X ray inactivation; the 95% confidence limits on the colony forming efficiencies (CFEs), the alpha and beta parameters from the LQ equation, the surviving percentage at 2 Gy, and the mean inactivation dose (D, Gy) are listed herein. The average D from these 16 colon tumor lines was 2.35 Gy (95% confidence limits 2.10-2.60 Gy), which indicates that these tumor cells are of equal radioresistance to melanoma or head and neck cells, with only glioblastoma cells being of greater radioresistance.

Bis(sulfo-N-succinimidyl) [15N,2H16]doxyl-2-spiro-4'-pimelate, a stable isotope-substituted, membrane-impermeant bifunctional spin label for studies of the dynamics of membrane proteins: application to the anion-exchange channel in intact human erythrocytes.

We have synthesized and characterized an isotopically substituted homologue of the membrane-impermeant bifunctional spin label bis(sulfo-N-succinimidyl) doxyl-2-spiro-4'-pimelate (BSSDP) [Beth et al. (1986) Biochemistry 25, 3824-3832] in which the nitroxide N is substituted with 15N and all of the protons in the doxylpimelate moiety are replaced by deuterons ([15N,2H16]BSSDP). Like its normal isotope homologue, [15N,2H16]BSSDP reacts with the anion-exchange channel in intact human erythrocytes at a site that spans the single extracytoplasmic chymotryptic cleavage site and that overlaps the stilbenedisulfonate site. The narrower line widths in the EPR spectrum of [15N,2H16]BSDP-labeled anion channels allow calculation of a minimum separation of 16 A between spin labels bound at the functionally important stilbenedisulfonate sites on adjacent subunits of an anion channel dimer. The 15N and 2H isotopic substitutions also provide substantial improvement in signal to noise of motionally sensitive regions of the ST-EPR spectrum of [15N,2H16]BSSDP-labeled anion channels in intact erythrocytes. [15N,2H16]BSSDP-labeled anion channels in intact erythrocytes were cross-linked to covalent dimers in the extracytoplasmic domain with the membrane-impermeant cross-linking reagent bis(sulfo-N-succinimidyl) suberate [Staros (1982) Biochemistry 21, 3950-3955], and the saturation-transfer EPR spectrum of these cells was compared with that of cells treated with [15N,2H16]BSSDP but not subsequently cross-linked. The spectra were essentially identical, supporting the hypothesis that anion channel subunits form stable dimers in the membranes of intact erythrocytes.

Axonal transport of [35S]methionine labeled proteins in Xenopus optic nerve: phases of transport and the effects of nerve crush on protein patterns.

Axonal transport of proteins in the Xenopus optic nerve was examined by labeling proteins in the eye with [35S]methionine injected intraocularly and then analyzing the labeled proteins in the eye, nerve, and tectum on linear gradient SDS polyacrylamide gels at different times after the injection. Because the optic nerve in Xenopus is short, in order to distinguish transported proteins from locally synthesized proteins, the optic nerve on one side of the animal was crushed at the orbit (to stop axonal transport) 5-30 min prior to injection and the crushed and normal nerve segments were compared. Proteins in the intact nerve which were absent in the crushed nerve were identified as axonally transported proteins. By such criteria several waves corresponding to transported material moving at greater than or equal to 6 mm/day, 1.6-2.8 mm/day, and approximately 0.2 mm/day were detected in the nerve. The most rapid phases of transport could be further resolved in the optic tectum into 3 additional components at 60-96 mm/day, 30-48 mm/day, and 6-11 mm/day. Analysis of labeled proteins in the crushed nerves distal to the crush, near the injury site, revealed several locally synthesized proteins (mol. wt. 54,000, 48,000, 43,000 daltons) which were not present in normal, uninjured nerves. Such proteins are probably synthesized by glia in response to injury.

Vertebrate class distribution of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetylhydrolase in serum.

Serum from numerous mammals and lower vertebrates contains an enzyme activity that is specific for the hydrolysis of the acetate moiety of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (PAF, platelet activating factor). Acetylhydrolase (EC 3.1.1.47, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine acetylhydrolase) was found in all mammalian sera with activity ranging from 11 (fetal calf) to 178 (rabbit) pmol acetate liberated/microliter serum/min. The enzyme is not present in avian serum but is a constituent of reptiles and bony fishes.