Surface modification of hydroxyapatite. Part II. Silica

Nanophase hydroxyapatite (HAP) particles were coated with varying amounts of silica (5-75wt%) via the hydrolysis of tetraethyl orthosilicate. The nanocomposite particles were characterized by transmission electron spectroscopy, X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), BET N(2) gas adsorption, sedimentation time studies, acid dissolution, and zeta potential (zeta). A sequential decrease in infrared spectral features characteristic of HAP was accompanied by an increase in features characteristic of silica as revealed by DRIFTS. The specific surface area of the silica-coated HAP particles showed a non-systematic increase. In comparison to the uncoated HAP (50m(2)/g), silica coatings of 5, 25, 50 and 75wt% yielded specific surface areas of 55, 93, 70, and 138m(2)/g, respectively. This behavior can be explained based on a heterocoagulation coating mechanism in which silica clusters of approximately 14nm in diameter adsorb onto the HAP particle surface. The decrease in specific surface area at 50wt% silica corresponded to the attainment of a complete surface coating. This conclusion was substantiated by the observed resistance of these particles to dissolution in 1M HCl. However, the acid treatment transformed the silica-coated HAP core particles to CaCl(2).Ca(H(2)PO(4))(2).2H(2)O (calcium chloride phosphate hydrate) based on XRD analysis.     

Physician Perception of IBS Management in Women and Men

Irritable bowel syndrome is a common gastrointestinal disorder that is manifested by abdominal pain and an alteration in bowel habits. It is estimated to occur in 20% of the US population and is diagnosed more frequently in women compared to men. The principles of management do not differ based upon gender. However, there is not data that has evaluated physician perception of IBS diagnosis and management. This study evaluated internal medicine physicians' perception of IBS in women and men. Sixty internal medicine physicians (30 men, 30 women) completed anonymous surveys evaluating their perception of the ease of diagnosis and management of IBS. A database was created and analyzed using Epi Info. Statistical significance was determined with chi-square tables that generated P values. IBS was more frequently diagnosed in women. There was a statistically significant difference in women with IBS being not easy to diagnose when compared to men with IBS (P=0.0003). There was also a statistically significant difference in men with IBS being reported to be not easy to manage when compared to women with IBS (P=0.0014). This study revealed that physicians perceive a difference in the ease of diagnosis and management of IBS based upon gender. Further research is necessary to gain insight into the influence of patient gender upon this disorder.     

Breast self-examination in women in two primary care settings: an evaluation of the impact of insurance status

Breast cancer is one of the most common cancers diagnosed among women in the United States. Screening tools available for breast cancer detection include breast self-examination (BSE), clinical breast examination, and mammography. Various studies have indicated that women may inconsistently perform BSE. This investigation evaluated the potential impact of insurance status on BSE. Women with health insurance receiving primary healthcare at a health maintenance organization (HMO) and women without health insurance receiving primary healthcare at a free clinic completed anonymous questionnaires that obtained information about the frequency of BSE performance, whether instruction was given about performing BSE, age at learning BSE, and confidence in performing BSE. One hundred fifty-five (82%) of 200 questionnaires at the HMO and 92 (92%) of 100 questionnaires at the free clinic were completed. Thirty-five percent of women (32% at the HMO, 39% at the free clinic) reported performing BSE. There were no significant differences in the rate of monthly BSE, receiving instruction about performing BSE, age at learning BSE, or confidence in performing BSE in women at the HMO and free clinic. Insurance status did not affect BSE. However, further study is needed to evaluate factors that potentially influence performance of BSE and could encourage compliance with BSE recommendations.     

Comparing outcomes of major models of police responses to mental health emergencies

OBJECTIVE: The study compared three models of police responses to incidents involving people thought to have mental illnesses to determine how often specialized professionals responded and how often they were able to resolve cases without arrest. METHODS: Three study sites representing distinct approaches to police handling of incidents involving persons with mental illness were examined-Birmingham, Alabama; and Knoxville and Memphis, Tennessee. At each site, records were examined for approximately 100 police dispatch calls for "emotionally disturbed persons" to examine the extent to which the specially trained professionals responded. To determine differences in case dispositions, records were also examined for 100 incidents at each site that involved a specialized response. RESULTS: Large differences were found across sites in the proportion of calls that resulted in a specialized response-28 percent for Birmingham, 40 percent for Knoxville, and 95 percent for Memphis. One reason for the differences was the availability in Memphis of a crisis drop-off center for persons with mental illness that had a no-refusal policy for police cases. All three programs had relatively low arrest rates when a specialized response was made, 13 percent for Birmingham, 5 percent for Knoxville, and 2 percent for Memphis. Birmingham's program was most likely to resolve an incident on the scene, whereas Knoxville's program predominantly referred individuals to mental health specialists. CONCLUSIONS: Our data strongly suggest that collaborations between the criminal justice system, the mental health system, and the advocacy community plus essential services reduce the inappropriate use of U.S. jails to house persons with acute symptoms of mental illness.     

Colorectal cancer surveillance in African-American and white patients at an urban university medical center.

Colorectal cancer causes significant morbidity and mortality in the United States. Recommendations for colorectal cancer screening have been developed. This study evaluated the colorectal cancer screening practices of African-American and white patients by internal medicine resident physicians. A retrospective chart review was conducted during 1989-1994. The performance of rectal examination, fecal occult blood testing, and flexible sigmoidoscopy among patients > 50 years was evaluated. The medical records of 200 patients (90 men and 110 women) were reviewed. Ninety-one rectal examinations, 26 fecal occult blood testing, and 30 flexible sigmoidoscopies were performed. There were 129 African-American (54 men and 75 women) and 52 white (26 men and 27 women) patients. Of the African-American patients, 57 underwent a rectal examination, 17 had fecal occult blood testing, and 26 underwent flexible sigmoidoscopy. Of the white patients, 24 had a rectal examination, 8 had fecal occult blood testing, and 12 underwent flexible sigmoidoscopy. These results demonstrate that resident physicians adhered poorly to colorectal cancer screening recommendations. There was no statistically significant difference in the screening of African-American and white patients. Increased efforts should be made to improve colorectal cancer screening practices by resident physicians.     

Inhibition of the immediate allergic reaction in the nose by the beta-2 adrenostimulant fenoterol

Sympathomimetic agents inhibit antigen-induced release of histamine in animal experiments and in in vitro studies of human tissue, but the significance of this effect for treatment of allergic airway diseases has not been established. It was the aim of our study to investigate the protective effect of the beta-2 adrenostimulant fenoterol on allergen-induced nasal symptoms and to relate the efficacy to dose and time. In a double-blind crossover design 16 patients with hay fever were challenged with grass pollen extract in the nose after pretreatment with intranasal placebo and fenoterol in different doses, delivered as a micronized powder from a pressurized canister and as a watery solution from a pump spray. Sneezing was recorded, and rhinorrhea and changes in nasal airway resistance were measured for 15 min after the provocation. Fenoterol, micronized powder as well as solution, had a marked inhibitory effect on all three nasal symptoms (p < 0.05) in doses ordinarily used for inhalation in the treatment of branchial asthma. The effect lasted for more than 4 hr. Our study has suggested that topical application of beta-2 adrenostimulants has a mast cell stabilizing effect in the airways and that these drugs may be of value for treatment of allergic rhinitis.     

Irritable bowel syndrome

Irritable bowel syndrome is a common gastrointestinal disorder characterized by abdominal pain and a change in bowel habits. It is estimated to occur in 9% to 22% of the US population, and is more often diagnosed in women than in men. There are no diagnostic markers for irritable bowel syndrome and no evidence of organic disease. Moreover, the pathophysiology is not completely understood; however, abnormal gastrointestinal motility, altered sensory activity, central neural dysfunction, psychological disturbances, and luminal factors have been proposed. Treatment requires a multifaceted approach. Education, dietary measures, fiber supplementation, and pharmacological and psychological interventions have been used in the management of this disorder.