Raetrad model extensions for radon entry into multi-level buildings with basements or crawl spaces

The RAETRAD model was generalized to characterize radon generation and movement from soils and building materials into multi-level buildings with basements or crawl spaces. With the generalization, the model retains its original simplicity and ease of use. The model calculates radon entry rates that are consistent with measurements published for basement test structures at Colorado State University, confirming approximately equal contributions from diffusion and pressure-driven air flow at indoor-outdoor air pressure differences of deltaP(i-o) = -3.5 Pa. About one-fourth of the diffusive radon entry comes from concrete slabs and three-fourths comes from the surrounding soils. Calculated radon entry rates with and without a barrier over floor-wall shrinkage cracks generally agree with Colorado State University measurements when a sustained pressure of deltaP(i-o) = -2 Pa is used to represent calm wind (<1 m s(-1)) conditions. Calculated radon distributions in a 2-level house also are consistent with published measurements and equations.     

Cryosurgical ablation of the normal ventral prostate plus adjuvant does not protect Copenhagen rats from Dunning prostatic adenocarcinoma challenge

PURPOSE: We wished to determine if cryosurgical ablation of the normal ventral prostate of Copenhagen rats confers protective immunity against a subsequent challenge with Dunning R3327 MatLyLu prostatic adenocarcinoma. In human melanoma, tumor antigens have been characterized as normal cellular proteins. We reasoned that cryosurgical ablation of the normal prostate along with immunostimulatory adjuvants might release prostatic antigens to the immune system engendering an immune response and rendering rats immune to prostatic cancer cells. MATERIALS AND METHODS: On day 0, Copenhagen rats underwent cryosurgical ablation of the normal ventral prostate, cryosurgery and intraprostatic injection of Complete Freund's Adjuvant (CFA), CFA injection alone, or laparotomy alone. On day 21, animals received a subcutaneous challenge of MatLyLu tumor cells. Tumor dimensions were recorded at regular intervals by a single blinded investigator. RESULTS: Animals receiving cryosurgical ablation of the normal ventral prostate or intraprostatic CFA developed tumors more frequently than animals receiving laparotomy alone and the effect was statistically significant if animals received both cryosurgical ablation of the prostate and intraprostatic CFA (3 experiments, 1 x 10(4) MatLyLu cells), total number with tumors/total number challenged: laparotomy alone 3/17, cryosurgical ablation 7/17, cryosurgery plus CFA 10/16 (p = 0.013 versus laparotomy, Fisher's exact test), CFA alone 9/17. CONCLUSIONS: Cryosurgical ablation of the normal rat ventral prostate and intraprostatic CFA does not protect against and can enhance the tumorigenicity of MatLyLu prostatic cancer cells at distant sites. This could be occurring through specific immunologic effects or non-specific mechanisms induced by cryosurgery and CFA.     

Cigarette smoking, weight gain, and coronary mortality: results from the Chicago Western Electric Study

BACKGROUND: Prospective studies of overweight and coronary heart disease (CHD) have presented inconsistent findings. Previous inconsistencies may be explained by the modifying effect of cigarette smoking on the association between weight gain and coronary mortality. METHODS AND RESULTS: We prospectively studied 1531 men 40 to 59 years of age who were employed at the Hawthorne Works of the Western Electric Company in Chicago, Ill. Information collected at the initial examination in 1958 included recalled weight at age 20, present weight, height, smoking status, and other CHD risk factors. Vital status was known for all men on the 25th anniversary: 257 CHD deaths occurred over 31,644 person-years of experience. Cox regression analysis was used to investigate risk of coronary mortality associated with change in body mass index (deltaBMI) and its modification by smoking status after adjustment for age, major organ system disease, family history of CHD, and BMI at age 20. Adjustment was not performed for blood pressure or serum total cholesterol because these are intervening variables. DeltaBMI was positively associated with risk of coronary mortality in never-smokers but not in current-smokers (P for interaction =.088). For never-smokers with deltaBMI classified as stable, low gain, moderate gain, or high gain, adjusted relative risks of coronary mortality were 1.00, 1.75, 1.75, and 3.07, respectively (P for trend=.010). For current-smokers, the respective adjusted relative risks were 1.00, 0.78, 1.05, and 1.03 (P for trend=.344). CONCLUSIONS: These results support the hypothesis that cigarette smoking modifies the association between weight gain and coronary mortality. Future investigations of weight gain and coronary mortality should account for the modifying effect of cigarette smoking.     

Diffusion-weighted MR imaging in hypertensive encephalopathy: clues to pathogenesis

We investigated the effects of organic buffers on the NO-like biological activities of ONOO-. In HEPES buffer (50 mM), ONOO- (1 mM) induced a 20-fold increase in endothelial cGMP accumulation and the effect was comparable to that elicited by a maximally active concentration of the NO donor DEA/NO. ONOO- produced a 12-fold increase of cGMP in MOPS buffer (50 mM), but was virtually inactive in phosphate buffer (50 mM). Electrochemical detection of NO showed that the biological effects of ONOO- in HEPES or MOPS were due to accumulation of compounds that released NO in the presence of copper ions. CuCl2-induced formation of NO was completely blocked by the Cu(I) chelator neocuproine but unaffected by the Cu(II) chelator cuprizone, pointing to a Cu(I)-catalyzed decomposition pathway. Formation of NO from ONOO- was not detectable in phosphate buffer, in agreement with the lack of effect of ONOO- on cGMP accumulation in this buffer. These data demonstrate that certain buffer components present in cell culture media may yield artificial results in experiments with authentic ONOO-.     

Sildenafil, a novel inhibitor of phosphodiesterase type 5 in human corpus cavernosum smooth muscle cells

In human corpus cavernosum, release of nitric oxide from the non-adrenergic, non-cholinergic nerves and/or the endothelium activates guanylyl cyclase and increases intracellular cGMP levels. The increase in intracellular cGMP modulates intracellular calcium and in turn regulates smooth muscle contractility and erectile function. Phosphodiesterases play an important physiological role by regulating the intracellular levels of cyclic nucleotides. In this study, we investigated the kinetic parameters of inhibition of phosphodiesterase (PDE) type 5 (E.C. 3.1.4.35 3',5'-cyclic GMP phosphodiesterase) by a novel, high affinity, selective PDE type 5 inhibitor, sildenafil, in soluble extracts of human corpus cavernosum smooth muscle cells. Sildenafil inhibited PDE type 5 cGMP-hydrolytic activity, in the crude extract (Ki=4-6 nM) and in partially purified preparations (Ki=2 nM) in a competitive manner, as determined by Dixon plots. Sildenafil (Ki=2-4 nM) was a more effective PDE type 5 inhibitor than zaprinast (Ki=250 nM). Stimulation of intracellular cGMP synthesis by the nitric oxide donor, sodium nitroprusside, resulted in less than a 5% increase in cGMP levels in the absence of sildenafil and a 35% increase in cGMP levels in the presence of sildenafil, in intact cells at physiological temperatures. These results are in accord with the clinical observations that sildenafil, taken orally, promotes penile erection through increased intracellular cGMP in response to sexual stimulation, potentiating smooth muscle relaxation.     

Managed care and unintended pregnancy

This article assesses the adequacy of coverage of contraceptive services and supplies for US women in the various types of managed care plans, with special attention to Medicaid. Between 1993 and 1995, the percent of insured private-sector employees enrolled in managed care plans rose from 51% to 73%. By 1996, the health care of 40% of low-income Medicaid recipients was also under managed care administration. Although 84% of managed care plans cover oral contraceptives--a rate substantially higher than that for traditional indemnity plans, several logistic factors impede access to this and other reproductive health benefits. The requirement of preauthorization may delay access to care when timely presentation is essential to the prevention of unwanted pregnancy. Some plans restrict members to one visit per year with an obstetrician-gynecologist. Coordination of an enrollee's total health care through the primary care physician can raise confidentiality problems for those who seek sensitive reproductive health services. There are fewer restrictions on the access of Medicaid recipients to family planning providers and services, but treatment of sexually transmitted diseases may not be part of the reproductive health package. The explosion of managed care onto the US health care market has led to public sector regulation legislation--a process that is proceeding in a piecemeal rather than comprehensive way. Because of the importance of reproductive health care to the lives of women, communities, and the broader society, more systematic action on this front is essential.