Disentangling the Effect of Local and Global Spatial Variation on a Mosquito-Borne Infection in a Neotropical Heterogeneous Environment

Mosquito-borne pathogen transmission exhibits spatial-temporal variability caused by ecological interactions acting at different scales. We used local spatial statistics and geographically weighted regression (GWR) to determine the spatial pattern of malaria incidence and persistence in northeastern Venezuela. Seven to 11 hot spots of malaria transmission were detected by using local spatial statistics, although disease persistence was explained only for four of those hot spots. The GWR models greatly improved predictions of malaria risk compared with ordinary least squares (OLS) regression models. Malaria incidence was largely explained by the proximity to and number of Anopheles aquasalis habitats nearby (1–3 km), and low-elevation terrains. Disease persistence was associated with greater human population density, lower elevations, and proximity to aquatic habitats. However, there was significant local spatial variation in the relationship between malaria and environmental variables. Spatial modeling improves the understanding of the causal factors operating at several scales in the transmission of malaria.     

MR imaging-guided cryoablation of metastatic brain tumours: initial experience in six patients

Objective  

The objective was to evaluate the initial experience and safety of magnetic resonance imaging (MRI)-guided transcranial cryoablation in cystic metastatic brain tumours.     

Detection of Hard Exudates in Retinal Images Using a Radial Basis Function Classifier

Diabetic retinopathy (DR) is one of the most important causes of visual impairment. Automatic recognition of DR lesions, like hard exudates (EXs), in retinal images can contribute to the diagnosis and screening of the disease. The aim of this study was to automatically detect these lesions in fundus images. To achieve this goal, each image was normalized and the candidate EX regions were segmented by a combination of global and adaptive thresholding. Then, a group of features was extracted from image regions and the subset which best discriminated between EXs and retinal background was selected by means of logistic regression (LR). This optimal subset was subsequently used as input to a radial basis function (RBF) neural network. To improve the performance of the proposed algorithm, some noisy regions were eliminated by an innovative postprocessing of the image. The main novelty of the paper is the use of LR in conjunction with RBF and the proposed postprocessing technique. Our database was composed of 117 images with variable color, brightness and quality. The database was divided into a training set of 50 images (from DR patients) and a test set of 67 images (40 from DR patients and 27 from healthy retinas). Using a lesion-based criterion (pixel resolution), a mean sensitivity of 92.1% and a mean positive predictive value of 86.4% were obtained. With an image-based criterion, a mean sensitivity of 100%, mean specificity of 70.4% and mean accuracy of 88.1% were achieved. These results suggest that the proposed method could be a diagnostic aid for ophthalmologists in the screening for DR.     

Prevalence of human papillomaviruses in urine samples of male patients infected with HIV‐1 in Sao Paulo,Brazil

Human papillomavirus is a DNA virus that includes 118 genotypes. HPV16 is responsible for 80% of cervical cancer in women. Men are important reservoirs and major transmitters of HPV to their partners. The aim of this study was to detect HPV DNA and to determine the prevalence of HPV types 6, 11, 16, and 18 in urine samples of men infected with HIV‐1. This study included 223 patients infected with HIV‐1 from the Center of Reference on HIV/AIDS (CRT‐SP) and an outpatient clinic of HIV. Urine samples were collected and after DNA extraction real‐time PCR was performed for detection of HPV DNA. Positive samples were then tested by conventional PCR using type‐specific primers for the four HPV types. A total of 223 men infected with HIV‐1 were tested, 81% of whom were on HAART. Four (5.8%) were positive for HPV6, 18 (26.1%) were positive for HPV11, 22 (31.9%) were positive for HPV16 and five (7.2%) were positive for HPV18 by conventional PCR. Twenty (29%) patients had other HPV types and five patients (1.5%) had multiple types. The mean T CD4+cells count was 517 and 441 cells/mm³ (P = 0.30), in HPV negative and positive men, respectively. The HIV viral load was higher in the HPV negative group than for in the men with HPV (P = 0.0002). A 30.9% prevalence of HPV was found in asymptomatic urine samples of men infected with HIV‐1. This study suggests that urine may be a useful specimen for HPV screening. J. Med. Virol. 81:2007–2011, 2009. © 2009 Wiley‐Liss, Inc.     

A familial inverted duplication/deletion of 2p25.1-25.3 provides new clues on the genesis of inverted duplications

We studied a family in which the same 10 Mb inverted duplication of 2p25.3-p25.1 segregates in two children and their father, all showing a trisomy phenotype. As FISH analysis demonstrated that the duplication was inverted, we suspected that a contiguous terminal deletion was also present, according to the classical inv dup del type of rearrangements. Although FISH with 2p and 2q subtelomeric probes gave normal results, 100 kb resolution array-C/GH (aCGH) showed that, beside the duplication, a 273 kb deletion was also present. The presence of a single-copy region between the deleted and duplicated regions was further suspected through high-resolution aCGH analysis (approximately 20 kb), although only one informative spot having a normal log ratio was detected. The precise structure of the rearrangement was re-defined by real-time PCR and breakpoint cloning, demonstrating the presence of a 2680 bp single-copy sequence between deleted and duplicated regions and the involvement of a simple repeat with the potential for forming a non-B DNA structure. The rearrangement was not mediated by segmental duplications or short inverted repeats, and the double-strand break might have been repaired by non-homologous end joining or microhomology-mediated intrastrand repair. These data highlight the fact that concomitant deletions associated with inverted duplications are very likely to be more frequent than classical cytogenetic methods alone have been able to demonstrate. The phenotypic effects of the trisomy and of the terminal 2p deletion are discussed.     

Immunohistochemical identification of MMP-2 and MMP-9 in human dentin: correlative FEI-SEM/TEM analysis

Matrix metalloproteinases (MMPs) are a family of peptidases trapped within mineralized dentin matrix and involved with degradation of the extracellular matrix components in hybrid layers and caries. Despite their identification through indirect evidences and biochemical assays, MMP-2 and -9 have not been localized within the human dentin extracellular organic matrix. Thus, this study aimed to assess the localization and distribution of MMP-2 and -9 in human dentin organic matrix by employing a correlative field emission in-lens-scanning electron microscopy (FEI-SEM) and transmission electron microscopy (TEM) immunohistochemical approach. Dentin specimens were submitted either to a preembedding or to a postembedding immunolabeling technique using primary monoclonal antibodies anti-MMP-2 and anti-MMP-9 and exposed to a secondary antibody conjugated with gold nanoparticles. MMP-2 and -9 labelings were identified in the demineralized dentin matrix as highly electron-dense gold particles dispersed on the collagen fibrils. Correlative FEI-SEM/TEM observations confirmed that MMP-2 and MMP-9 are endogenous components of the human dentin organic matrix and revealed the three-dimensional relationship between these proteinases and the collagen fibrils, showing that both antibodies yielded a similar labeling pattern. In conclusion, the results of the study contribute to reveal distinct distribution pattern of gelatinases and support the hypothesis that these enzymes are intrinsic constituents of the dentin organic matrix after decalcification.     

Vaginal cuff dehiscence after hysterectomy: a multicenter retrospective study

Objective

This study estimates the incidence of vaginal cuff dehiscence resulting from different approaches to hysterectomy.

Study design

This multicentric study was carried out retrospectively. We retrospectively analyzed 8635 patients; 37% underwent abdominal hysterectomy, 31.2% vaginal hysterectomy, and 31.8% laparoscopic hysterectomy. All the hysterectomies were considered, vaginal evisceration was registered and analyzed for time of onset, trigger event, presenting symptoms, details of prolapsed organs and type of repair surgery. Continuous variables were compared using the one-way analysis of variance between groups as all data followed a Gaussian distribution, as confirmed by the Kolmogorov–Smirnov test. Differences among subgroups were assessed using the Tukey–Kramer multiple comparisons test. Categorical variables were compared with two tailed Chi-square tests with Yates correction or Fisher's exact test, as appropriate. Pearson's linear correlation was used to verify linear relationships between the dehiscence interval and patient's age at surgery.

Results

Thirty-four patients (0.39%) experienced vaginal evisceration. The laparoscopic route was associated with a significantly higher incidence of dehiscence (p < 0.05). No differences were found between the 6027 patients (69.8%) who had closure of the vaginal cuff and the 2608 (30.2%) who had an unclosed cuff closure technique.

Conclusion

Vaginal evisceration after hysterectomy is a rare gynecological surgical complication. Sexual intercourse before the complete healing of the vaginal cuff is the main trigger event in young patients, while evisceration presents as a spontaneous event in elderly patients. Surgical repair can be performed either vaginally or laparoscopically with similar outcomes.