1-Butanol absorption in poly(styrene-divinylbenzene) ion exchange resins for catalysis.

The swelling behaviour of poly(styrene-co-divinylbenzene), P(S-DVB), ion exchange resins in 1-butanol (BuOH) has been studied by means of atomistic classical molecular dynamics simulations (MD). The topological characteristics reported for the resin in the dry state, which exhibited complex internal loops (macropores), were considered for the starting models used to examine the swelling induced by BuOH contents ranging from 10% to 50% w/w. Experimental measurements using a laser diffraction particle size analyzer indicate that swelling causes a volume variation with respect to the dry resin of 21%. According to MD simulations, such a volume increment corresponds to a BuOH absorption of 31-32% w/w, which is in excellent agreement with the indirect experimental estimation (i.e. 31% w/w). Simulations reveal that, independently of the content of BuOH, the density of the swelled resin is higher than that of the dry resin, evidencing that the alcohol provokes important structural changes in the polymeric matrix. Thus, BuOH molecules cause a collapse of the resin macropores when the content of alcohol is ≤20% w/w. In contrast, when the concentration of BuOH is close to the experimental value (∼30% w/w), P(S-DVB) chains remain separated by pores faciliting the access of the reactants to the reaction centers. On the other hand, evaluation of both bonding and non-bonding interactions indicates that the mixing energy is the most important contribution to the absorption of BuOH into the P(S-DVB) resin. Overall, the results displayed in this work represent a starting point for the theoretical study of the catalytic conversion of BuOH into di-n-butyl ether in P(S-DVB) ion exchange resins using sophisticated electronic methods.

Embarazo gemelar con mola hidatiforme completa coexistiendo con feto / Twin pregnancy with complete hydatid mole coexisting with the fetus

Se presenta un caso de embarazo gemelar consistente en mola hidatiforme completa coexistiendo con feto, diagnosticado en la semana 15 de gestación. Es un raro fenómeno, con una incidencia de 1:22.000 a 1:100.000 embarazos. Estas pacientes tienen un alto riesgo de desarrollar una enfermedad trofoblástica persistente. Las investigaciones prenatales mostraron por ecografía una placenta heterogénea sugerente de un desorden trofoblástico coexistiendo con un feto morfológicamente normal, asociado con niveles preevacuación muy elevados de -HCG (3.320.000 mUI/ml).El proceder terapéutico debe ser individualizado y dependerá de la viabilidad fetal, del deseo de la paciente de continuar el embarazo, de la edad gestacional estimada y de la condición clínica de la paciente. En este caso, la paciente presentó las graves complicaciones descritas en la mola clásica (preeclampsia, metrorragia..) junto a la gran elevación de -HCG. Se adoptó una actitud radical activa (histerectomía total con feto intraútero), con rápida regresión de los niveles séricos de -HCG tras la evacuación (AU)

[Evaluation of 2 tuberculosis chemoprophylaxis regimens in patients infected with human immunodeficiency virus. The GECMEI Group]. / Evaluación de dos pautas de quimioprofilaxis tuberculosa en pacientes infectados por el virus de la inmunodeficiencia humana. Grupo GECMEI.

OBJECTIVE: To assess the compliance, tolerance and efficacy of a short chemoprophylaxis regimen (IR) for tuberculosis using isoniazid (INH) plus rifampin (RIF) during 3 months versus a standard regimen (I) of isoniazid during 12 months in HIV positive patients. MATERIAL AND METHODS: Prospective, comparative, randomized and open clinical trial in four general hospitals and one prison hospital of Castilla-La Mancha. Prophylaxis was administered to PPD-positive patients and to anergic patients according to the CDC recommendations (1991). Patients were randomized in two treatment groups: regimen IR, isoniazid 300 mg daily and rifampin 600 mg daily; regimen I, isoniazid 300 mg during 12 months. RESULTS: 133 patients were included, 64 to regimen I and 69 to regimen IR. Regimen IR had a better tolerance with a 28% of adverse effects versus 55% in regimen I. Hepatotoxicity was more frequent in regimen I with a RR = 2.2 (CI 95% 1.23-4.01). Severe hepatotoxicity leading to treatment withdrawal was related to drug administration time and was more frequent in the 12 months regimen group. Short regimen showed a better compliance, without significant differences. Tuberculosis incidence rate was a 4.23 cases/100 persons--year for regimen I and 2.08 in regimen IR, with a relative risk for developing tuberculosis with regimen IR group of 0.51 (CI 95% 0.09-2.8) versus regimen I group, without statistical significance. Prison stay was associated to a significant risk for tuberculosis, regardless of both regimens (RR = 9.2 CI 95%, 1.06-80.2). CONCLUSIONS: In HIV-infected patients with PPD(+) or anergic, regimen with IR is at least as effective as regimen I for preventing the development of tuberculous disease, and has less adverse effects.

Cefminox versus Cefoxitin in Hysterectomy Prophylaxis : Clinical Efficacy and Serum and Tissue Concentrations.

This phase III, prospective, randomised, open, controlled clinical trial compared the efficacy of single-dose cefminox (2g) versus triple-dose cefoxitin (2g every 4 hours) as antibiotic prophylaxis in 112 women undergoing gynaecological surgery (vaginal or abdominal hysterectomy). Peak, intraoperative and trough serum concentrations were determined for both antibiotics, as well as their concentrations in myometrial tissue in a subset of patients from the study (22 patients from the cefminox group and 18 from the cefoxitin group). Clinical response was satisfactory in all women treated with cefminox (59 of 59) and in 52 of 53 patients treated with cefoxitin. Fever-related morbidity, hospital stay and adverse reactions were similar in both groups. Peak serum concentrations were 132.3 mg/L for cefminox and 82.2 mg/L for cefoxitin. 12-hour concentrations were 2.82 mg/L for cefminox and 2.17 mg/L for cefoxitin, and were higher than the respective minimum inhibitory concentrations (MICs) for pathogens commonly associated with this pathology. Uterine tissue concentrations were 24.5 and 41.6 mg/L for cefminox and cefoxitin, respectively, and also clearly exceeded MIC. It was shown that the use of a single preoperative dose of cefminox was similar in efficacy to 3 doses of cefoxitin administered every 4 hours, and that the serum and tissue concentrations attained provide adequate antibiotic coverage. In view of the general trend towards the use of a single dose for prophylaxis, cefminox offers a new alternative for antibiotic prophylaxis in gynaecological surgery.

Comparative bioavailability of a dispersible formulation of diclofenac and finding of double plasma peaks.

We carried out a comparative study of the bioavailability of a typical, enteric-coated diclofenac with regard to a new dispersible formulation whose faster dissolution results in an earlier onset of its analgesic effect. This randomized, crossover study was conducted in 12 healthy male volunteers, who received in fasting 100 mg of enteric-coated diclofenac (Dolotrén, FAES) and 100 mg of dispersible diclofenac (Dolotrén Dispersable, FAES), with one-week interval between both. Blood samples were taken at pre-established times during the 24 hours after dosing, and plasma concentrations of diclofenac were determined by HPLC. Possible adverse experiences were monitored with a check-list, and blood and urinalysis were performed for safety assessment. The dispersible formulation showed a relative extent of bioavailability between 78% and 99% (90% CI) for the AUC0-infinity, being the 90% CI for the Cmax 63%-129%. The time to Cmax (Tmax) was significantly shorter with the dispersible than with the enteric-coated formulation (95% CI for the difference = 1.5-4.25 hours) as the T0(lag) or time to measurable plasma concentrations (1.9-4.2 hours, 95% CI). A relevant feature in the study was the finding of a second peak at 2-2.5 hours post-dosing in 7 out of 11 profiles of subjects receiving the dispersible formulation. Both formulations were well tolerated in clinical and laboratory terms. In conclusion, the new dispersible formulation of diclofenac allows absorption to begin more rapidly and plasma peak is reached earlier, a fact that may be relevant to the analgesic treatment of acute pain.

Osteoarticular infection in intravenous drug abusers: influence of HIV infection and differences with non drug abusers.

OBJECTIVES: To determine (a) the influence of HIV in developing osteoarticular infections in intravenous drug abusers (IVDAs) and (b) the differences between the clinical features of osteoarticular infections in IVDAs and a control group of non-IVDAs. METHODS: A comparative study of the clinical features of osteoarticular infections in all HIV positive and HIV negative IVDAs admitted to the departments of rheumatology and internal medicine during a 10 year period was carried out. The joint infections of all IVDAs, irrespective of HIV status, were compared with those of a control group of non-IVDAs lacking risk factors for HIV infection. RESULTS: A total of 482 HIV positive and 85 HIV negative IVDAs was studied, in whom 25 (5%) and six (7%) osteoarticular infections were found respectively. There were no differences in age, sex, joints affected, and causative agents between these two groups. A comparison of the 31 (5.5%) osteoarticular infections in all IVDAs with 21 infections in 616 (3.4%) non-IVDAs showed significant differences in the mean age (27.5 v 54), the frequency of affection of the axial joints (hip, sacroiliac, and sternocostal joints) (64.5% v 16.6%), and in the incidence of Candida albicans (19% v 0%). CONCLUSIONS: (1) HIV may not predispose to osteoarticular infections in IVDAs. (2) The hip, sacroiliac, and sternocostal joints (axial joints) were most commonly affected in IVDAs. (3) In Spain, unlike other countries, Gram positive bacteria and C albicans seem to be predominant agents in osteoarticular infections in IVDAs, with a low incidence of Gram negative bacteria.