Twiddler's syndrome and pectoral stimulation in a patient with dual-site unipolar atrial pacing.

Twiddler's syndrome is a rare condition of pacemaker rotation; when associated with unipolar pacing it could provoke extracardiac muscular stimulation. We report a case of an obese woman who unintentionally reversed her triple-chamber, dual-site unipolar atrial pacemaker, implanted for the prevention of paroxysmal atrial fibrillation. The extracardiac pectoral stimulation was due to unipolar atrial stimulation. The polarity mode was not programmable and output reduction was unsuccessful. Thus, the problem was resolved noninvasively by means of external manual rotation of the pacer. At 24 months of follow-up, the patient was still free of symptoms.     

New carvacrol and thymol derivatives as potential insecticides: synthesis,biological activity,computational studies and nanoencapsulation

New compounds with potential insecticide activity were synthesized by structural modifications performed in the monoterpenoid phenolic moieties of carvacrol and thymol, resulting in a set of derivatives with the ether function containing the propyl, chloropropyl or hydroxypropyl chains, as well as a bicyclic ether with an unsaturated chain containing a carboxylic acid terminal. In addition, an analogue of carvacrol and thymol isomers bearing methoxyl, 1-hydroxyethyl and (3-chlorobenzoyl)oxy, instead of the three original methyl groups, was also synthesized. Several structural changes that resulted in diminished insecticide activity have been identified, but two significantly active molecules have been synthesized, one of them being less toxic to human cells than the naturally-derived starting materials. Structure-based inverted virtual screening and molecular dynamics simulations demonstrate that these active molecules likely target the insect odorant binding proteins and/or acetylcholinesterase and are able to form stable complexes. For the most promising compounds, nanoencapsulation assays were carried out in liposomes of egg phosphatidylcholine/cholesterol (7 : 3) prepared by both thin film hydration and ethanolic injection methods. The compound-loaded liposomes were generally monodisperse and with sizes smaller than or around 200 nm. The thin film hydration method allowed high encapsulation efficiencies (above 85%) for both compounds and a delayed release, while for the systems prepared by ethanolic injection the encapsulation efficiency is lower than 50%, but the release is almost complete in two days.

Thymol and carvacrol derivatives were synthesised. Two of them proved to be mildly active against Sf9 insect cell line and one has presented selectivity by proving to be less toxic to human cells than the naturally derived starting materials.     

The influence of temporal resolution in determining pharmacokinetic parameters from DCE‐MRI data

We investigated the influence of the temporal resolution of dynamic contrast‐enhanced MRI data on pharmacokinetic parameter estimation. Dynamic Gd‐DTPA (Gadolinium‐diethylene triamine pentaacetic acid) enhanced MRI data of implanted prostate tumors on rat hind limb were acquired at 4.7 T, with a temporal resolution of ～5 sec. The data were subsequently downsampled to temporal resolutions in the range of 15 sec to 85 sec, using a strategy that involves a recombination of k‐space data. A basic two‐compartment model was fit to the contrast agent uptake curves. The results demonstrated that as temporal resolution decreases, the volume transfer constant (K^trans) is progressively underestimated (～4% to ～25%), and the fractional extravascular extracellular space (v_e) is progressively overestimated (～1% to ～10%). The proposed downsampling strategy simulates the influence of temporal resolution more realistically than simply downsampling by removing samples. Magn Reson Med 63:811–816, 2010. © 2010 Wiley‐Liss, Inc.     

Rhombencephalosynapsis: CT and MRI findings

An unusual disorder of cerebellar development, rhombencephalosynapsis is a unique entity which presents with cerebellar fusion and absence of cerebellar vermis on imaging studies, often associated with supratentorial findings. No specific clinical syndrome has been described in these patients so far, and most cases are found in infancy and childhood. MRI and its multiplanar capabilities and high spatial and contrast resolution increased its recognition. Two cases are reported, with emphasis on imaging findings.     

Aedes aegypti (l.) population in an endemic area of dengue in Southeast Brazil

OBJECTIVE: A Aedes aegypti population from an area of dengue transmission was studied to determine mosquito's frequency, spatial distribution, parity, its ovarian development and midgut contents. METHODS: The study carried out in S?o José do Rio Preto country, S?o Paulo, SP, Brazil. Low and intermediate socioeconomic level regions were chosen to the study, which was carried out 1996 and 1997. Using a manual electric aspirator, captures were performed inside and outside the houses. Dissections were conducted to allow classify female mosquitoes according to their physiologic state. RESULTS: One hundred and eighty-eight males and 189 females were captured in both regions. A general index of 0.46 Ae. aegypti females per house was determined. Of the total sample, 82.4% of males and 87.3% of females were collected indoors. Greater proportions of females were found in the region of low socioeconomic level, and higher population density. One hundred and forty-eight female mosquitoes were analyzed: 27.0% were nulliparous and 10.1% parous. The rest were classified as Christophers and Mer's (C & M) phases III to V, 28.0% of which had red blood in their midgut. Of the total female population, 87.9% had bloodmeals. CONCLUSIONS: The mosquito species revealed a high degree of endophily. There was a higher proportion of nulliparous mosquitoes, although the majority of the females were classified as C & M's phases III to V. These results highlight both the great number of females who had had bloodmeals, and the lack of gonotrophic concordance.     

Clinical and histologic characteristics of breast cancers in women with previous pathologic diagnosis of benign breast disease in Spain

Women with a benign breast disease (BBD) have an increased risk of subsequent breast carcinoma. Information is scarce regarding the characteristics of breast carcinomas diagnosed after a BBD. Our aim was to point out the differences in clinical and histologic characteristics of breast carcinomas diagnosed in women with and without a previous pathologic diagnosis of BBD in the context of population‐based mammography screening. Retrospective cohort study of all women aged 50‐69 years who were screened at least once in a population‐based screening program in Spain, between 1994 and 2011 and followed up until December 2012. The mean follow‐up was 6.1 years. We analyzed 6645 breast carcinomas, of whom 238 had a previous pathologic diagnosis of BBD. Information on clinical and histologic characteristics was collected from pathology reports. Logistic regression was used to estimate the odds ratio (OR) and 95% confidence intervals (95%CI) of occurrence of selected histologic characteristics of breast carcinomas in women with and without a previous BBD. Women with a previous BBD had a higher proportion of ductal carcinoma in situ (DCIS) compared with women without a BBD (22.1% and 13.6%, respectively). Among those diagnosed with an invasive breast carcinoma, women with previous BBD were more likely to be diagnosed with carcinomas sized >2 cm (OR = 1.46; 95%CI = 1.03‐2.08), metastatic positive (OR = 2.66; 95%CI = 1.21‐5.86), and with a high Ki‐67 proliferation rate (OR = 1.93; 95%CI = 1.24‐2.99). No differences were found across histologic subtypes of BBD. Screening participants with a previous pathologic diagnosis of BBD had a higher proportion of DCIS. However, invasive carcinomas detected in women with a BBD were associated with clinical and histologic characteristics conferring a worst prognosis.