Atmospheric Spectroscopy and Photochemistry at Environmental Water Interfaces.

The air-water interface is ubiquitous in nature, as manifested in the form of the surfaces of oceans, lakes, and atmospheric aerosols. The aerosol interface, in particular, can play a crucial role in atmospheric chemistry. The adsorption of atmospheric species onto and into aerosols modifies their concentrations and chemistries. Moreover, the aerosol phase allows otherwise unlikely solution-phase chemistry to occur in the atmosphere. The effect of the air-water interface on these processes is not entirely known. This review summarizes recent theoretical investigations of the interactions of atmosphere species with the air-water interface, including reactant adsorption, photochemistry, and the spectroscopy of reactants at the water surface, with an emphasis on understanding differences between interfacial chemistries and the chemistries in both bulk solution and the gas phase. The results discussed here enable an understanding of fundamental concepts that lead to potential air-water interface effects, providing a framework to understand the effects of water surfaces on our atmosphere.

Impacts of cloud water droplets on the OH production rate from peroxide photolysis.

Understanding the difference between observed and modeled concentrations of HOx radicals in the troposphere is a current major issue in atmospheric chemistry. It is widely believed that existing atmospheric models miss a source of such radicals and several potential new sources have been proposed. In recent years, interest has increased on the role played by cloud droplets and organic aerosols. Computer modeling of ozone photolysis, for instance, has shown that atmospheric aqueous interfaces accelerate the associated OH production rate by as much as 3-4 orders of magnitude. Since methylhydroperoxide is a main source and sink of HOx radicals, especially at low NOx concentrations, it is fundamental to assess what is the influence of clouds on its chemistry and photochemistry. In this study, computer simulations for the photolysis of methylhydroperoxide at the air-water interface have been carried out showing that the OH production rate is severely enhanced, reaching a comparable level to ozone photolysis.

Effects of the substituents on the reactivity of carbonyl oxides. A theoretical study on the reaction of substituted carbonyl oxides with water.

The reactions between fifteen carbonyl oxides and water have been investigated with the aim of contributing to a better understanding of the effects of the substituents in the reactivity of carbonyl oxides. We have employed density functional theory and large scale ab initio methods (CCSD(T), CASSCF, and CASPT2), combined with transition state theory, to investigate the addition of water to carbonyl oxide and, for those carbonyl oxides having a methyl substituent in syn, the hydrogen transfer from the methyl group to the terminal oxygen of carbonyl oxide. In this case, the water acts as a catalyst and this reaction can contribute to the atmospheric formation of a hydroxyl radical. Carbonyl oxides with electron withdrawing substituents and zwitterionic character have low energy barriers and react fast, whereas carbonyl oxides with electron releasing substituents have high energy barriers and react slowly. The position of the substituents plays also an important role and carbonyl oxides having a hydrogen atom substituent in syn react faster than carbonyl oxides having a hydrogen atom substituent in anti. The differences in the reactivity of different substituted carbonyl oxides raise up to ten orders of magnitude and the branching ratios for the two different reactions investigated are also reported.

A multicenter double-blind study comparing lovastatin and gemfibrozil in the treatment of primary hypercholesterolemia.

The efficacy and tolerability of lovastatin and gemfibrozil were compared in a randomized double-blind 12-week study including 182 patients with primary hypercholesterolemia, from 7 hospitals in Spain. Inclusion criteria were total-cholesterol of at least 250 mg/dl and triglycerides less than 350 mg/dl. Patients were stratified in two groups: group 1, cholesterol less than 300 mg/dl, and group II, cholesterol equal to or more than 300 mg/dl. Patients were randomized to gemfibrozil (600 mg b.i.d.) or lovastatin (20 mg q.p.m., group I and 40 mg q.p.m., group II). If after 6 weeks of treatment cholesterol remained above 200 mg/dl, lovastatin does were doubled. In group I, lovastatin decreased cholesterol by 20%, LDL-C by 28%, and triglycerides by 17%, and increased HDL-C by 8%. In group II the results were: -26%, -33%, -19% and +6% respectively. The corresponding results with gemfibrozil were: -8%, -9%, -28% and +14% (group I); and -13%, -14%, -33% and +9% (group II). In both groups, lovastatin was more effective in reducing cholesterol and LDL-C (P less than 0.001) and gemfibrozil in reducing triglycerides (P less than 0.05 group I and P less than 0.01 group II). Both drugs were well tolerated. Thus, lovastatin and gemfibrozil are effective lipid-lowering agents; lovastatin has more pronounced effects in patients with hypercholesterolemia.

Prevalence of osteomyelitis in non-healing diabetic foot ulcers: usefulness of radiologic and scintigraphic findings.

The study was conducted in order to assess the prevalence of osteomyelitis and the predictive value of radiographic (xR) and combined Tc 99-bone and leukocyte scanning (CS) findings in diabetic foot ulcers that met criteria for hospital admission (FUH). Out of 150 episodes of ulceration managed in an outpatient basis, 33 (in 28 NIDDM patients) requiring admission were evaluated. In all cases plain xR and CS were carried out. Seventeen episodes (51.5%) had a good outcome (healed or improving, at the time of the last follow up). Osteomyelitis was found in 21 episodes and 14 (66.6%) of them required an amputation. In 13 cases where xR showed characteristic radiologic changes of osteomyelitis (11 of them had a positive CS) 11 (84.6%) underwent an amputation. However, when osteomyelitis was diagnosed only by a positive CS, only 3/8 (37.5%) required a toe amputation. Severe peripheral vasculopathy was present in 44% of cases who required amputation and only in 17.6% of those who did not. We conclude that in FU underlying osteomyelitis is frequent and associated to a higher amputation rate than when no bone infection is identified (66.6 vs 17%), even when corrected for vascular status (OR 11, CI 95% 1.65-74.2), with a worse outcome when xR changes are already present.

Antibodies to human immunodeficiency virus (HIV-1) in autoimmune diseases: primary Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis and autoimmune thyroid diseases.

The aetiology of autoimmune diseases remains unknown. The relationship between virus, and more recently retrovirus, has been suggested with this group of diseases. Immunoblotting is a useful method for determining the presence of proteins coded by different retrovirus genes. Since the prevalence of these types of proteins in patients with primary Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and autoimmune thyroid diseases has not been fully established, the aim of this work was to determine the prevalence of antibodies to immunodeficiency human virus type 1 (HIV-1) proteins in these diseases and their possible relationship with the presence of anti-nuclear, anti-DNA, anti-SSA (Ro) and anti-SSB (La) autoantibodies. Antibodies to human immunodeficiency virus (HIV-1) were studied in a group of 341 patients with autoimmune diseases (77 SS, 98 SLE, 75 RA, 91 autoimmune thyroid diseases) and 126 blood donors as a control group. A Western blot was used to detect antibodies to HIV-1, and a double polymerase chain reaction (PCR) using nested primers in the gag and pol gene of HIV-1. Antinuclear antibodies, anti-DNA, anti-SSA (Ro) and anti-SSB (La) were determined by enzyme-linked immunosorbent assays. At least one band was shown on immunoblotting in 26% of patients with autoimmune diseases and 35% of controls. The presence of antibodies to p55 or p68 proteins in patients with SS or SLE proved to be the only statistically significant difference between the other autoimmune diseases studied and the control group. These antibodies were not associated with autoantibodies ANA, DNA, SSA (Ro) or SSB (La).(ABSTRACT TRUNCATED AT 250 WORDS)

Tamoxifen failure in medullary thyroid carcinoma.

We report the results of short-term tamoxifen treatment (20 mg two times a day orally) in 2 patients with metastatic medullary thyroid carcinoma. Patient A had a rapid tumor progression with development of Cushing's syndrome before initiation of tamoxifen treatment. Patient B had a slowly progressive course. In both cases, neither clinical nor biochemical improvement were observed, after 1 and 3 months of tamoxifen therapy, respectively.

[Bronchial-associated lymphoid tissue lymphoma]. / Linfoma de tejido linfoide asociado al bronquio (BALT).

Two cases of non-Hodgkin's endobronchial or bronchial-associated lymphoid tissue lymphoma are reported; such cases are either extremely rare or underestimated. We emphasize the need to perform endoscopic examination in patients with lymphoma and clinical findings that suggest bronchial disease.

Limitations in the use of attachments in a Mediterranean population.

It has been asserted that the average height of natural teeth in Mediterranean Latin populations is relatively short and that these teeth are of insufficient size to host standard attachments manufactured by different companies. The occlusogingival height of 159 potential abutment teeth from 50 Spanish patients was measured and compared to the sizes of intracoronal and extracoronal attachments available from one manufacturer. Twenty-one abutments (13% of the sample) were smaller than the smallest intracoronal attachment available. Eighty-seven percent of the abutments in the sample would have allowed the use of an attachment. However, only 11% of the sample would have allowed the use of a large intracoronal or medium extracoronal attachment, and none would have been able to host a large extracoronal attachment. In addition, 35% of the sample could only have accepted a small intracoronal attachment. In such cases, the capacity for retention would have to be carefully evaluated.

Study of the mandibular movements during swallowing.

The authors recorded the mandibular movement produced during the swallowing of 150 ml of water with the aid of a straw between the lips using a kinesiograph in a random sample of 66 people between the ages of 24 and 35. In each recording 13 variables were measured, and a descriptive analysis of each one was carried out. The authors' findings support that there is no dental contact during liquid swallowing with the aid of a straw between the lips.

[Psychosis as the initial manifestation of systemic lupus erythematosus: the role of lupus band test and anti-ribosomal antibodies]. / Psicosis como manifestación inicial de lupus eritematoso sistémico: valor de la prueba de la banda lúpica frente a los anticuerpos antirribosomales.

INTRODUCTION: Diffuse brain disease in systemic lupus erythematous (SLE) can be difficult to assess because of the sparse biological expression of the disorder, resulting in usually normal neuroimaging and laboratory findings. For this reason, it is likely that patients without a previous SLE diagnosis that presented initially with a pure psychiatric disorder, as psychosis or depression, can remain undiagnosed, and, in fact, they are exceptionally reported. As a biological marker, antiribosomal P protein antibodies have been closely related to SLE psychosis although their pathogenic role and specificity is under discussion. CLINICAL CASE: A young woman, without relevant medical history, presented with an acute psychotic catatonic picture, suspected organic in nature due to the existence of persistent mild CSF pleocytosis, while neuroimaging and laboratory studies were negative, including antinuclear and antiribosomal antibodies. Finally, a SLE diagnosis could be established because of a strong lupic band phenomenon in skin biopsy. CONCLUSIONS: It is important to maintain a high suspicion of SLE in acute psychotic patients, especially if atypical features are present. As the biological expression of the disorder in such cases may be elusive, we propose the study of lupus band in skin biopsy for these patients, regardless the absence of antiribosomal antibodies.

Role of vibrational anharmonicity in atmospheric radical hydrogen-bonded complexes.

Harmonic and anharmonic vibrational frequency calculations are reported for the most stable hydrogen bonded complexes formed between the hydroperoxyl radical and formic, acetic, nitric, and sulfuric acids which are of atmospheric interest. A comparison between the calculated IR spectra of the hydrogen bonded complexes with the corresponding separate monomers is also reported with the aim to facilitate a possible experimental identification of these complexes. The calculations have been carried out using the second-order vibrational perturbative treatment implemented by Barone applied to the PES obtained with the B3LYP functional using the 6-31+G(d,p) and 6-311+G(2d,2p) basis sets. Our calculations for the separate monomers predict vibrational frequencies with quite a good agreement with the experimental values. The anharmonic contribution results in differences of around 40 cm(-1) with respect to the harmonic values; although in some cases involving highly anharmonic modes, these differences can rise up to 300 and 450 cm(-1).