Chrysotile and chrysophosphate chemical modification of the chrysotile surface and its effect on biological behavior.

Chrysotile asbestos was reacted with phosphorus oxychloride (POC) gas to produce a chemically modified fiber referred to as chrysophosphate. The presence of phosphorus and chlorine on the fiber surface and in small fiber bundles was verified by means of energy dispersive x-ray spectrometry and laser mass spectrometry. The altered fiber exhibits different physical-chemical properties when compared with the unaltered precursor material. In addition to marked surface changes, fibrils of the reacted material appear to be cross-linked increasing the size of particulates, fiber bundles and increasing their mechanical stability. The reacted specimens exhibit fewer fibrils reducing their surface area. In vitro testing using the human erythrocyte model showed the membranolytic activity of the reacted fiber to be substantially reduced to the background level measured for mechanical membrane breakage during manipulation. Membranolytic activity of unreacted chrysotile displayed values reported previously in the literature. These data support the observation made in other studies that fiber surface modification by means of an industrial process may be a method for reducing the biological potential of mineral particles. The membrane model is considered a useful and preliminary examination. These materials will require further testing in more complex in vivo systems. Some in vivo assays were performed on chrysophosphate with results that appeared to differ from our membrane tests. These differences are described and the variation of batch chemistry, stability of the reacted surface, and the resulting surface chemistry, are discussed.

Cluster randomised trial of an active, multifaceted educational intervention based on the WHO Reproductive Health Library to improve obstetric practices.

OBJECTIVE: We conducted a trial to evaluate the effect of an active, multifaceted educational strategy to promote the use of the WHO Reproductive Health Library (RHL) on obstetric practices. DESIGN: Cluster randomised trial. The trial was assigned the International Standardised Randomised Controlled Trial Number ISRCTN14055385. SETTINGS: Twenty-two hospitals in Mexico City and 18 in the Northeast region of Thailand. METHODS: The intervention consisted primarily of three interactive workshops using RHL over a period of 6 months. The focus of the workshops was to provide access to knowledge and enable its use. A computer and support for using both the computer and RHL were provided at each hospital. The control hospitals did not receive any intervention. MAIN OUTCOME MEASURES: The main outcome measures were changes in ten selected clinical practices as recommended in RHL starting approximately four to six months after the third workshop. Clinical practice data were collected at each hospital from 1000 consecutively delivered women or for a 6-month period whichever was reached sooner. RESULTS: The active, multifaceted educational intervention we employed did not affect the ten targeted practices in a consistent and substantive way. Iron/folate supplementation, uterotonic use after birth and breastfeeding on demand were already frequently practiced, and we were unable to measure external cephalic version. Of the remaining six practices, selective, as opposed to routine episiotomy policy increased in the intervention group (difference in adjusted mean rate = 5.3%; 95% CI -0.1 to 10.7%) in Thailand, and there was a trend towards an increased use of antibiotics at caesarean section in Mexico (difference in adjusted mean rate = 19.0%; 95% CI: -8.0 to 46.0%). There were no differences in the use of labour companionship, magnesium sulphate use for eclampsia, corticosteroids for women delivering before 34 weeks and vacuum extraction. RHL awareness (24.8-65.5% in Mexico and 33.9-83.3% in Thailand) and use (4.8-34.9% in Mexico and 15.5-76.4% in Thailand) increased substantially after the intervention in both countries. CONCLUSION: The multifaceted, active strategy to provide health workers with the knowledge and skills to use RHL to improve their practice led to increased access to and use of RHL, however, no consistent or substantive changes in clinical practices were detected within 4-6 months after the third workshop.

A controlled clinical trial of vitamin E supplementation in patients with congestive heart failure.

BACKGROUND: Oxidative stress is increased in patients with congestive heart failure and can contribute to the progressive deterioration observed in these patients. Increased oxidative stress is the result of either an increased production of free radicals or a depletion of endogenous antioxidants, such as vitamin E. OBJECTIVE: We aimed to determine whether vitamin E supplementation of patients with advanced heart failure would modify levels of oxidative stress, thereby preventing or delaying the deterioration associated with free radical injury. DESIGN: Fifty-six outpatients with advanced heart failure (New York Heart Association functional class III or IV) were enrolled in a double-blind randomized controlled trial for 12 wk. At a baseline visit and at 2 follow-up visits, blood and breath samples were collected for the measurement of indexes of heart function and disease state, including malondialdehyde, isoprostanes, and breath pentane and ethane. Quality of life was also assessed at baseline and after 12 wk of treatment. RESULTS: Vitamin E treatment significantly increased plasma concentrations of alpha-tocopherol in the treatment group but failed to significantly affect any other marker of oxidative stress or quality of life. In addition, concentrations of atrial natriuretic peptide (a humoral marker of ventricular dysfunction), neurohormonal-cytokine markers of prognosis, tumor necrosis factor, epinephrine, and norepinephrine were unchanged with treatment and were not significantly different from those in the control group. CONCLUSION: Supplementation with vitamin E did not result in any significant improvements in prognostic or functional indexes of heart failure or in the quality of life of patients with advanced heart failure.

Ethnography of fertility and menstruation in rural Mexico.

In rural populations in Mexico, the system of ideas in relation to the reproductive cycle is built on a mestizo base, with pre-Colombian and Western elements. The objective of the study was the analysis of concepts and resources related to human reproduction in Morelos, in order to design a primary reproductive health care program. The use of ethnographic methods helped identify bio-cultural constructs on which the communities base their reproductive patterns. Our main research results reveal that these populations attribute great value to the extension of the family through descendants. Women's sexuality is directly linked to reproduction and blood is the supremely feminine substance. Great importance is consistently attributed to menstruation about which well-defined concepts exist in the community, where as pre-menarche changes are perceived as a state of bio-psychosocial maturity. Menarche beyond 14 years of age is considered abnormal and is attributed to an 'excess of cold' in the body, therapy is usually administered by traditional birth attendants. In the mythical explanations given for bleeding, the moon plays a fundamental role, as the first rupture of the hymen is attributed to it. A general lack of knowledge about ovulation and its relation to reproduction was observed, resulting in incorrect contraceptive practices.

A comparison of biofeedback-assisted cardiodeceleration in type A and B men: modification of stress-associated cardiopulmonary and hemodynamic adjustments.

The primary purpose of this experiment was to examine the cardiac effects of instructions and biofeedback to reduce heart rate during both rest and a behavioral stressor. A second purpose was to assess respiratory, hemodynamic, and metabolic function in conjunction with heart rate. A final aim was to compare the effects of biofeedback on Type A and B men. Type A subjects fell in the upper 10% of the distribution of Jenkin's Activity Survey scores and Type B subjects fell in the lower 10%. Subjects experienced one of three instructional sets during an initial session: instructions to reduce heart rate with biofeedback; instructions to reduce heart rate without biofeedback; and instructions to sit quietly. During a second session, all subjects received identical instructions prior to the behavioral stressor. Heart rate, pulmonary gas exchange, and ventilation were measured breath-by-breath. During the first session, the groups did not differ in any measured parameter, but Type As had higher heart rates than did Type Bs across all conditions. During the second session, subjects given instructions to reduce heart rate with and without biofeedback did not differ in heart rate; as expected, however, both of these groups had smaller increases in heart rate than did the control group. Interestingly, the tachycardia of the control group occurred without an increase in oxygen consumption, indicating a cardiac-metabolic dissociation in this group. The modification of heart rate without a concomitant change in metabolism is important in understanding the association between cardiac and metabolic function.

Pneumoconiosis associated with exposure to glass and abrasive particles.

A patient with a history of decorating glass fixtures by means of abrasive etching presented with a disease characterized by diffuse infiltrates on chest roentgenogram and restriction and diffusion impairment on pulmonary function testing. Mineralogic analysis of biopsied pulmonary lesions showed particles consistent in composition to the glasses etched and abrasives used. The former particles were noncrystalline. Silicate mineral phases were identified as well, these displaying crystalline properties. Previous studies of workers exposed to abrasives, ie, silicon carbide and emery (as a form of corundum) suggest slight pneumoconiotic risk exists; this is also the case for workers exposed to forms of industrially made glass. The question is raised as to whether there exists, in this present case, an etiological association between exposure to respirable glassy particles and the development of pulmonary scarring.

Vitamin profile of 174 mothers and newborns at parturition.

Thiamin, biotin, B12, folate, pantothenate, riboflavin, nicotinate, B6, vitamins A, E, C, and beta-cartene was estimated in the blood of 174 mothers and in the cord blood of their neonates at parturition. A vitamin profile of normal preganancy was established for mother and neonate. This was based on values obtained from 95 percent confidence limits in 74 mothers not taking oral vitamins and 133 mothers ingesting various vitamin supllements. Circulating vitamin levels in 38 neonates born to mothers with no laboratory evidence of hypovitaminemia was persented. The higher incidence of hypobitaminemia in gravidas not taking vitamins was folate, thiamin, vitamins A, C, B12, BL and nicotinate in descending order. Ingestion of vitamins supplements reduced the incidence of hypovitaminemia. A similar relationship held for neonates from these mothers. However, despite vitamin ingestion thiamin, folate, vitamins C, A, B6, B12 and nicotinate hypovitaminemia was evident. There was an approximate 1:2-5 ratio between mother and neonate blood vitamins; vitamins A, B6, E, and beta-carotene were exceptions. Vitamin B6 ran parallel, while vitamins A, B6, E, and beta-carotene ratios reversed in favor of the mother at an approximate ratio of 2:1, 4:1 and 7:1, respectively. It is concluded that vitamin profile for mother and neonate, taking into account values established from a lorge gravid population, should now permit an evaluation of the effects of hypoviteminemia on the outcome of pregnancy and infant health.