The Effect of Montmorillonite Clay on the Crystallinity of Poly(vinyl alcohol) Nanocomposites Obtained by Solution Intercalation and In Situ Polymerization.

In this study, PVAL/sodic clay nanocomposite materials were obtained using different clay ratios. The nanocomposites were prepared by solution and in situ polymerization. They were characterized through proton relaxometry and X-ray diffraction, the latter technique used to determine the crystallinity of the PVAL matrix in the nanocomposites through the addition of unmodified montmorillonite clay. The relaxation data for the nanocomposite films obtained by solution intercalation showed a decrease in the proton spin-lattice relaxation values with increased clay proportion, forming a nanostructured material with high exfoliation degree, as a result of two phenomena: the higher molecular mobility of the polymer chains around the clay layers and the presence of paramagnetic metals in the clay layers, which accelerates the hydrogen relaxation process, causing a decrease in the relaxation value. The samples obtained through in situ polymerization were mixed nanocomposites (partly exfoliated and partly intercalated). The NMR relaxation data for the systems analyzed showed the solution intercalation process was more efficient than in situ polymerization in relation to the generation of nanostructured polymers with higher degree of exfoliated clay.

Renal tuberculosis: a case report.

Tuberculosis or TB (tubercle bacillus) remains a major public health problem in developing countries. Over the last decades extrapulmonary locations of the disease have become more frequent due to the increased prevalence of acquired immune deficiency syndrome and the increase number of organ transplants. The urogenital localization represents about 27% of all extra-pulmonary localizations of TB and may be due either to a disseminated infection or to a primitive genitourinary localization. The majority of patients, has pyuria, sometimes with hematuria. The diagnosis of urinary tuberculosis is based on the finding of pyuria in the absence of infection by common bacteria. The initial medical treatment includes isoniazide, rifampicin, pyrazinamide, ethambutol and streptomycin. This disease should be suspected in patients with unexplained urinary tract infections, especially if immunocompromised and/or coming from endemic areas.

[Contact allergy to topical ophthalmological drugs - epidemiological risk assessment]. / Kontaktallergien gegen ophthalmologische Lokaltherapeutika - eine epidemiologische Risikobewertung.

BACKGROUND: Contact allergies (CA) against active agents of topical ophthalmological therapeutics, causing inflammation of the conjunctiva and/or the lid, are usually not life-threatening, but occur not infrequently. As yet, the assessment of the CA-eliciting risk has been based on clinical data alone, while a valid epidemiological risk assessment is lacking. MATERIALS AND METHODS: The Information Network of Departments of Dermatology supplied information on diagnostic results obtained in 4,102 patients patch-tested for suspected CA to ophthalmic drugs between 1995 and 2004. Clinical prevalences were extrapolated to incidences at the German population level. These estimates served as numerator for a relative incidence (RI), which included the nationwide frequency of prescriptions collected by the WIdO, Bonn, in terms of a standardised defined daily dose (DDD) as denominator. RESULTS: The estimated annual incidence of CA ranges from 155 (atropine sulphate) to 2077 (gentamicin sulphate) and can thus be regarded as moderate. If incidence estimates are related to prescription frequencies, the highest risk was found for kanamycin and neomycin sulphate (RI > 8 / 100,000 DDD). In contrast, the RI of pilocarpine-HCl (0.3) was virtually negligible. CONCLUSIONS: The substance-specific risk of CA has been evaluated for the first time and found to differ between therapeutics (with a similar spectrum of application). CA risk should be considered in differential therapeutic decision-making.

Allergic contact dermatitis to topical drugs--epidemiological risk assessment.

PURPOSE: Estimation of the population-based relative incidence (RI) of contact sensitization to a set of topical drug allergens (cases/100,000 defined daily doses (DDDs) per year) (1995-2004) and comparison of the RI for drugs with a similar therapeutic scope. METHODS: Clinical data regarding the frequency of contact sensitization to important topical drug allergens in Germany were obtained from the Information Network of Departments of Dermatology (IVDK). This was extrapolated to the general population level using the 'clinical epidemiology and drug utilization research' (CE-DUR) approach. As denominator of exposure, national prescription data (DDDs of topical drug specialties) provided by the WIdO Research Institute (Bonn) were aggregated per substance. RESULTS: The probable RIs of contact sensitization to topical 'skin' corticosteroids ranged from 0.3 (dexamethasone phosphate disodium salt) to 23.3 (amcinonide) cases/100,000 DDDs per year. Concerning topical aminoglycoside antibiotics, the RI of framycetin sulphate was about threefold higher than that of gentamicin sulphate. Regarding topical ophthalmic use, the RI of kanamycin sulphate was higher compared to gentamicin sulphate. Active principles marketed over-the-counter (OTC) had, in general, lower RIs, with the exception of bufexamac, benzocaine, clioquinol and phenylephrine. CONCLUSIONS: The population-based risk assessment--quantitatively considering exposure in the RI estimation--revealed a ranking of contact sensitization risk to topical drugs which partly differed from the respective frequencies in the clinical patch test population. Some drugs available OTC carry non-negligible risk, too. The current findings should contribute to differential therapeutic considerations regarding topical drug use.

Contact allergy to topical drugs: prevalence in a clinical setting and estimation of frequency at the population level.

OBJECTIVES: To estimate the prevalence of contact allergy (CA) to a set of topical drugs patch tested in the research network IVDK (Information Network of Departments of Dermatology; www.ivdk.org) between 1995 and 2004, and to extrapolate these clinical data to the German population. METHODS: Clinical data comprised results of allergy patch tests with topical drugs in patients with suspected CA. Clinical epidemiology and drug utilization research (CE-DUR) methods were employed to grossly estimate the incidence of CA to these topical drugs during two 5-year periods (1995-1999 and 2000-2005) in the German general population. To estimate the number of persons eligible for patch testing (with the topical drugs) on a general population level, sales data of patch test material were obtained. By relating this denominator to the CA frequency observed in the IVDK, the incidence of CA to selected topical drugs in the German general population was crudely estimated. RESULTS: In general, topical aminoglycosides showed the highest CA frequencies and, except for gentamicin sulfate, frequencies of CA to all other allergens tested were lower in the 2nd period of analysis. According to the medium model, 1-year incidence rates ranged from 1 (hydrocortisone-17-butyrate) to 29 persons/100,000 (neomycin sulfate) in the general population (1995-1999). CONCLUSION: The CE-DUR approach yielded incidence estimates of CA to relevant topical drugs in the German general population, which, despite their limited precision in absolute terms, illustrate the relative frequency of this particular adverse effect. However, comparative risk assessment should preferably take exposure information into account.

High incidence of adverse reactions to initial antiretroviral therapy in Brazil

A concurrent prospective study was conducted from 2001 to 2003 to assess factors associated with adverse reactions among individuals initiating antiretroviral therapy at two public referral HIV/AIDS centers in Belo Horizonte, MG, Brazil. Adverse reactions were obtained from medical charts reviewed up to 12 months after the first antiretroviral prescription. Cox proportional hazard model was used to perform univariate and multivariate analyses. Relative hazards (RH) were estimated with 95 percent confidence intervals (CI). Among 397 charts reviewed, 377 (95.0 percent) had precise information on adverse reactions and initial antiretroviral treatment. Most patients received triple combination regimens including nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and protease inhibitors. At least one adverse reaction was recorded on 34.5 percent (N = 130) of the medical charts (0.17 adverse reactions/100 person-day), while nausea (14.5 percent) and vomiting (13.1 percent) were the most common ones. Variables independently associated with adverse reactions were: regimens with nevirapine (RH = 1.78; 95 percent CI = 1.07-2.96), indinavir or indinavir/ritonavir combinations (RH = 2.05; 95 percent CI = 1.15-3.64), female patients (RH = 1.93; 95 percent CI = 1.31-2.83), 5 or more outpatient visits (RH = 1.94; 95 percent CI = 1.25-3.01), non-adherence to antiretroviral therapy (RH = 2.38; 95 percent CI = 1.62-3.51), and a CD4+ count of 200 to 500 cells/mm³ (RH = 2.66; 95 percent CI = 1.19-5.90). An independent and negative association was also found for alcohol use (RH = 0.55; 95 percent CI = 0.33-0.90). Adverse reactions were substantial among participants initiating antiretroviral therapy. Specially elaborated protocols in HIV/AIDS referral centers may improve the diagnosis, management and prevention of adverse reactions, thus contributing to improving adherence to antiretroviral therapy among HIV-infected patients.

Contact allergy to neomycin sulfate: results of a multifactorial analysis.

PURPOSE: To perform a comprehensive, multifactorial analysis of potential risk factors (demographic and clinical) for contact allergy to neomycin sulfate, a common adverse reaction resulting from the topical use of this drug; especially in some subgroups of the population. METHODS: Retrospective analysis of allergy test data of the Information Network of Departments of Dermatology (IVDK, www.ivdk.org) between 1998 and 2003, including all patients patch tested with a standard screening series because of suspected allergic contact dermatitis (ACD). As one outcome, a positive (allergic) test reaction to neomycin sulfate was considered. An alternative outcome included only those patients with a positive test to neomycin sulfate and a final diagnosis of ACD. The association between outcome and potential risk factors was analyzed with Poisson regression analysis, deriving prevalence ratios (PR) as risk estimates. RESULTS: Of the 47,559 patients tested, 2.5% had positive reactions to neomycin sulfate, while in 1.1% ACD was additionally diagnosed. The results of the multifactorial analysis indicated that the risk of both outcomes decreased slightly during the period covered; was higher among patients with leg dermatitis; varied significantly with age and increased progressively with the number of additional positive reactions to other standard series allergens. Cross-reactivity to other, selectively tested, aminoglycoside antibiotics was substantial (kappa = 0.67; 95%CI: 0.63-0.71) for framycetin sulfate, to low (kappa = 0.33; 95%CI: 0.27-0.37) for gentamicin sulfate. CONCLUSIONS: The prevalence of contact sensitization to neomycin sulfate was noteworthy among patients patch tested in the IVDK centers. Supplementing clinical epidemiology, neomycin contact allergy has been estimated to be relatively common even on the level of the unselected population (prevalence approx. 1%). Hence, the topical use of neomycin sulfate by patients should be carefully monitored, considering its potential to induce ACD, with emphasis on subgroups at risk.