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Astatine-211 is considered to be one of the most promising alpha-emitters in targeted alpha therapy (TAT). However, its development has been hindered by its not so well understood chemistry. Hence, any attempt to understanding it better is imperative. Here, we show through DFT calculations that the neutral endohedral Al13 cluster follows a reactivity pattern very similar to At, more than any other halogen. The halogen and alkali bonding with Al13 and At presented a strong similarity in their charge transfer processes. Moreover, upon the interchange of At with Al13, we found a stable configuration of the compound corresponding to the astatination of aryliodonium salts, which have been considered as possible precursors for the synthesis of 211At-labeled tracers. Our results provide promising proof of concept that the Al13 cluster mimics the behaviour of At and might help in better understanding its chemistry and in streamlining the chemical processes of radiolabeling biomolecules.

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BACKGROUND: House dust mites are a ubiquitous air allergen in the human habitat. It has been shown that exposure to them is a fundamental factor in sensitisation and development of atopic disease. The objective of the study was to analyse changes in sensitisation to Dermatophagoides pteronyssinus (Der p.) in children treated in a tertiary level care hospital in Mexico City for a period of 11 years and compare with other studies carried out in Mexico. METHODS: A retrospective study was performed at the Hospital Infantil de México Federico Gómez (HIMFG). Information was gathered from skin tests for Der p. performed in the Allergy Laboratory from January 2004 to April 2015. Patients 2-18 years old who presented for examination of some type of allergic condition and who had immediate hypersensitivity tests to Der p. were included in the study. Results were compared with prior reports from other institutions. Descriptive analysis and χ2 statistics were used. RESULTS: A total of 8794 patients were included in the study; 49.3% of the tests (95% CI 48-50) were positive for Der p. The percentage of monosensitised to mites was 2.7% for Der p. (95% CI 2-3). A significant difference was found between the results of older patients and those <6 years old. The frequency of sensitisation had a tendency to decrease during the 11 years analysed in all age groups. CONCLUSIONS AND CLINICAL RELEVANCE: The frequency of sensitisation to Der p. increased with age until reaching adolescence. In the last 11 years a decrease in sensitisation to this air allergen was observed.

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Silicene, the graphene-like crystal formed by the Si hexagonal lattice, presents a periodic buckled structure whose origin is due to the pseudo Jahn-Teller instability on each of its planar six membered rings. This has been attributed to the coupling of the planar D6h ground state with the first b2g excited state through a b2g vibrational mode. Here we show, by explicitly calculating the vibronic coupling constants through a complete study of the PJT effect, that the vibronic coupling of the ground state with only one excited state to explain the planar instability is inconsistent with the linear multilevel PJT effect theory. It is also shown that in order to have consistency, the PJT model should include the next excited state, which is symmetry compatible coupled to the puckering mode. This is done by the analysis, based on DFT and TDDFT calculations, of the vibronic instability of the ground state of hexasilabenzene, the basic silicon hydrogenated hexagonal ring unit defining silicene.

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In this work we present the results of relativistic DFT calculations of magnetic moments for manganese inserted into a gold ring (Mn@Au6) or a cage-like structure (Mn@Au12) both pristine and n-thiolated. Optimization has been carried out to obtain different isomers always favouring the endohedral gold clusters with Mn inside. For the total magnetic moment (from electronic population analysis) verification of the jellium model has been performed in each case. It is concluded that the magnetic moments arise largely from the doped manganese atom and that thiolation can modulate its value, which is not present in the pure form. In the Mn@Au12 clusters we observed the formation of a hole in their structure; this could be a characteristic of insertion of a highly ferromagnetic dopant in some metal clusters, such as gold, and this could act as a precursor of the formation of gold magnetic nanotubes.

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Enteroparasites in children from three marginal urban districts of Trujillo (Peru) were studied to treat these children and to design a prevention and control programme. A total of 845 children were examined. The general prevalence of enteroparasites was of 66.3%, and 45.6% were multiparasitized. The pathogenic enteroparasite prevalence were 23.8% (Giardia lamblia), 4.6% (Iodamoeba buschlii), 2.6% (Cyclospora cayetanensis), 2.2% (Hymenolepis nana), and 2% (Cryptosporidium spp.). G. lamblia was the most frequent parasite both in diarrheic children (28.1%) as well as in nondiarrheic ones (19.5%). The G. lamblia genotypes were molecularly characterized by sequence analysis of the glutamate dehydrogenase (gdh) gene using PCR and RFLP. Sequence analysis revealed both Assemblage A (AI and AII) and Assemblage B (BIV), with the predominance of Assemblage AI. All the samples with Assemblage A were diarrheic but not those with Assemblage B. This is the first study of molecular characterization of G. lamblia in Peruvian children and confirms the importance of asymptomatic patients in the transmission of the giardiosis, especially in places with poor hygiene and sanitation.

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Intestinal parasitism was studied in children of Trujillo (Peru) to create a prevention and control program. Fecal samples of 489 children were examined. The general prevalence of intestinal parasitosis was found to be 68%. The most frequent pathogenic enteroparasites were Giardia lamblia (26.4%), Cyclospora cayetanensis (13%), Hymenolepis nana (2%), Hymenolepis diminuta (1.6%), and Cryptosporidium spp. (1%). All these parasites appeared both in diarrheic and nondiarrheic children, except Cryptosporidium, which invariably caused diarrhea. Multiple parasitism was frequent, 45.6% of the children presenting two, three, or four intestinal parasites. Cryptosporidium was the only parasite that was not associated with the others. Only five children were affected of cryptosporidiosis, presenting explosive diarrhea, nausea, and vomiting. Cryptosporidium species and genotypes involved in the infantile cryptosporidiosis were determined by polymerase chain reaction-restriction fragment length polymorphism. Four children were parasitized by Cryptosporidium hominis and only one by Cryptosporidium parvum. Our results confirm that anthroponotic transmission of Cryptosporidium is predominant in Peru.

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OBJECTIVE: Percutaneous mitral valvotomy (PMV) is an alternative to the surgical treatment of mitral stenosis. Results obtained with PMV appear to depend on the echocardiographical characteristics of the valvular apparatus. The purpose of this study was to report the immediate and late-term results with PMV. The incidence of late events (restenosis, mitral valve replacement and death), and their correlation with echocardiographic score (Wilkin's score) are also discussed. METHODS: Between December 1987 and August 1999, a total of 160 PMVs were performed at our institution. Ninety-six patients with a minimum of 6 months follow-up and echocardiographic evaluation of the mitral valve (Wilkin's score) before and after the procedure were selected for this study. Follow-up was available for 99% of the patients, with a mean follow-up of 33 +/- 22 months (range, 6 months to 11 years). Hazard ratio (HR) and Cox's regression were used for statistical analyses. RESULTS: PMV was successfully performed in 97% of the cases; in 84%, the result was considered optimal. The incidence of complications related to the procedure was 10%; no mortality was observed due to PMV. Severe mitral regurgitation was observed in 7% of the patients, but only 3% of the total group developed ventricular dysfunction or worsened their New York Heart Association functional class. Eight-four percent of the patients were free of late events at the end of the follow-up period. A restenosis rate of 34% was observed during follow-up; this rate did not correlate with age, functional class or atrial fibrillation. Restenosis was associated with pulmonary hypertension (HR 2.85; 95% confidence interval, 0.68-11.80). Also, Wilkin's score was not useful to predict the development of restenosis or clinical events in the mid- to long-term. CONCLUSION: In our series, PMV had a high immediate success rate and a low incidence of complications due to the procedure. Incidence of late events was also low and was unrelated to the Wilkin's score; however, recurrence of stenosis was observed in one-third. Pulmonary hypertension should be considered to be an important clinical predictor of restenosis.

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The population of patients who have congestive heart failure of ischemic origin is large and growing. It imposes a heavy burden on human suffering and economic costs such as the chronic use of costly medications, recurrent hospital admissions, and, eventually, death or the necessity of heart transplantation. Therefore, the development of methods for detecting viable myocardium may allow the accurate selection of those patients with coronary artery disease with severe left ventricular dysfunction who are most likely to benefit from revascularization, but also excludes patients who are unlikely to obtain any improvement with revascularization techniques. The presence of reversible dysfunctional myocardium that may improve after revascularization implies the concepts of stunned and hibernating myocardium. Recent evidence suggests that hibernation may not be a stable condition since it might evolve toward an irreversible dysfunction if it is not revascularized at the right moment. The techniques available for viability studies are single-photon emission computed tomography using thallium-201 or compounds labeled with technetium-99m, positron emission tomography, and dobutamine stress echocardiography. Newer and promising techniques are magnetic resonance imaging and contrast echocardiography, whose definitive roles are not clear yet. There is abundant evidence from several important studies showing that patients with a significant amount of viable myocardium have a poor outcome if they are treated medically. Conversely, if these patients are revascularized, their outcomes improve and their symptoms significantly decrease, with less necessity of medication, fewer admissions to the hospital, and even in some cases avoiding heart transplantation. On the other hand, patients with poor or no viability who are revascularized do not obtain significant benefit.

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BACKGROUND: Endoscopic ligation is the treatment of choice for bleeding esophageal varices. The usefulness of additional sclerotherapy is not clear. AIM: To assess the effectiveness of ligation followed by sclerotherapy in the treatment of variceal bleeding. PATIENTS AND METHODS: Forty eight patients with variceal bleeding admitted for emergency treatment and 73 patients admitted for elective treatment were studied. Varices were ligated until a significant reduction in size was achieved. Eradication was completed with the injection of 1% polidocanol. RESULTS: In 34 of 48 patients admitted for emergency treatment, the site of variceal rupture was identified. In all these subjects, and in 13 of 14 patients in whom the rupture site was not identified, hemorrhage was stopped with the procedure. Varices were eradicated in 108 of the 121 patients. Hemorrhage recidivated in 12.5% of patients admitted for emergency treatment, in a period of 14 months of follow up and in 9.6% of those admitted for elective treatment, in a period of 16 months follow up. Mortality was 14, 18 and 57% among patients classified as Child Pugh A, B or C, respectively. CONCLUSIONS: Endoscopic ligation is effective in the treatment of variceal bleeding. Adding sclerotherapy, variceal eradication is achieved in a high percentage of patients. Survival depends on hepatic function.

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BACKGROUND: Sclerosis, injection of cianoacrylate and rubber band ligation are the most commonly used endoscopic techniques for the treatment of bleeding esophageal varices. AIM: To assess the effectiveness of cianoacrylate and polidocanol in the treatment of bleeding esophageal varices. PATIENTS AND METHODS: Sixty eight patients with active variceal bleeding were studied. Bleeding varices were classified as thin, thick or gastric. Bleeding from thin varices was treated with polidocanol. Bleeding from thick or gastric varices was treated with cianoacrylate. Variceal eradication was done with polidocanol. RESULTS: Bleeding came from thin esophageal varices in 23% of patients and endoscopic treatment stopped bleeding in 95% of them, from thick esophageal varices in 62% and endoscopic treatment was successful in 94% of these, and from gastric varices in 12% and treatment stopped bleeding in 87% of these (in 3% bleeding was considered subcardial). Twenty-five percent of patients bled again during variceal eradication, 12% died due to uncontrollable bleeding and 20% died due to liver failure. During variceal eradication 59% of patients classified as Child Pugh C, died. CONCLUSIONS: Treatment of bleeding esophageal varices with cianoacrylate or polidocanol is effective. Patients classified as Child Pugh C have a had prognosis.

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A great progress in the knowledge about hepatitis virus has occurred in the last decades and several virus have been identified. Virus B, C and D are transmitted parenterally, while virus A and E use the enteral route. Highly effective vaccines for A and B hepatitis are presently available. Virus C is an important cause of chronic liver disease at the present moment. Since the identification of virus C and E, the number of acute hepatitis denominated as non A non B has decreased considerable. Although there are still patients with viral hepatitis of unknown origin and there is considerable effort to identify the agents causing them. Virus G and TT are frequently present in the sera of patients with chronic liver diseases but their real pathogenic role is not completely elucidated.

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BACKGROUND: The high prevalence of chronic hepatitis C virus infection in patients with porphyria cutanea tarda, specially in those without family history of the disease, suggests that this could be an acquired disease and one of the most frequent extra hepatic manifestations of hepatitis C virus infection. AIM: To study the excretion of porphyrins and its precursors in cirrhotic patients with and without hepatitis C virus infection. PATIENTS AND METHODS: Eighteen patients with cirrhosis Child-Pough A, eight infected with hepatitis C virus, were studied. Urinary excretion of [symbol see text] aminolevulinic acid, porphobilinogen, coproporphyrins, uroporphyrins and fecal excretion of coproporphyrins and protoporphyrins were measured. Red blood cell protoporphyrin was also measured. RESULTS: There were no differences in the measured parameters between patients with or without hepatitis C virus infection. No patient had uroporphyrin excretion values over the normal range. Some patients had slight elevations in some parameters, but always below the values observed in porphyrias. CONCLUSIONS: In these group of patients, hepatitis C virus infection of its associated liver disease, do not cause detectable alterations in porphyrin metabolism.

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Risk of perforation is a major impediment to the use of polyvinyl bougies in palliative dilation of cancerous strictures of the esophagus. We encountered 23 patients with complex malignant strictures in whom initial dilation with Savary-Gilliard bougies was thwarted because attempts to pass a conventional Eder-Puestow guide wire were unsuccessful. As a recourse, we probed these strictures with a very flexible guide wire of the type used to implant prostheses in the biliary tract. The purpose was to establish a passage through which a standard guide wire could then be inserted. The procedure was successful in all but 4 of the 23 patients. We conclude that in such cases the preliminary use of the very flexible guide, even though time-consuming, improves the chance of effective dilation with minimal added risk.

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The presence of hepatitis C virus antibodies was studied in 64 patients with non alcoholic liver disease and found in 11 (17%). The greater frequency of positive antibodies was found among patients with cryptogenetic liver disease, specially those without serum auto-antibodies (32%). The antibody was unusually found (0 to 11%) in non alcoholic liver diseases of other etiologies. It is concluded that hepatitis C virus chronic infections may be the etiology of an important number of non alcoholic chronic liver diseases.

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The prevalence of hepatitis C antibody was studied using the EIA 2 Abbott assay in patients and staff of the San Juan de Dios Hospital Hemodialysis Unit. The antibody was detected in 29.8% of patients, no member of the staff had positive antibodies. Patients with a positive antibody had been on hemodialysis for a longer time than those with a negative test (53.3 +/- 18.8 vs 37.9 +/- 33.5 months respectively). No differences in the number of transfusions received were observed between patients with positive or negative antibodies. Hepatitis B surface antigen was detected in 2 patients, with negative hepatitis C virus antibody. No clinical evidence of liver disease was found among patients with positive antibodies.

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The aim of this study was to assess the effect of propranolol treatment on the recurrence of variceal bleeding and mortality in patients with hepatic cirrhosis. Fifty seven patients were studied; they were recruited within 15 days of an episode of variceal bleeding, assigned randomly to receive propranolol (n = 29) placebo (n = 28) and followed during 4 years. Three patients were lost from follow up and in 3 propranolol was discontinued due to secondary effects. Bleeding recurrence was less frequent in the treated patients (Kaplan Meier analysis p < 0.01). Ten patients on placebo and 1 receiving the active drug died. Life table analysis showed a significantly better survival in the group of patients treated with propranolol. It is concluded that propranolol decreases the recurrence of variceal bleeding and improves survival in patients with hepatic cirrhosis.

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