Surgery for right ventricle to pulmonary artery conduit obstruction: risk factors for further reoperation.

OBJECTIVE: To identify the surgical approaches and risk factors which influence longevity of right ventricle to pulmonary artery (RV-PA) conduits following first reoperation for obstruction. METHODS: Between January 1993 and August 2003, 114 patients underwent 141 reoperations for RV-PA conduit obstruction. Diagnoses included 'Truncus Arteriosus' (n=52), 'Pulmonary atresia/Tetralogy of fallot' (n=39), 'Double outlet right ventricle' (n=10), 'Transposition of great arteries, VSD, and pulmonary atresia' (n=9), and the 'Ross operation' (n=4). All patients had undergone a previous biventricular repair. The first reoperation for conduit obstruction was performed in 112 hospital survivors by: total conduit replacement (Group A, n=73) with valved (homograft=10 and xenograft=54) or non-valved (n=9) conduit, and patch enlargement of the obstructed RV outflow tract with preservation of the posterior and sides of the conduit wall after removing of the fibrocalcific peel and degenerated valve (Group B, n=39). Mean age at first reoperation was 8.8+/-6.7 and 7.5+/-5.3 years in patients of groups A and B, respectively. Seven patients in Group A and 18 in Group B required a second reoperation and two patients in Group B a third reoperation. RESULTS: There were two hospital deaths and no late deaths. Mean follow-up was 5.8+/-3.2 years. Risk factors for second reoperation by univariate analysis were: homograft conduit use (P=0.004), Group B surgical approach (P=0.0001), higher RV-PA systolic pressure gradient at discharge (P=0.02), and age <5-years-old (P=0.01). Multivariate analysis showed that inclusion in Group B and younger age (<5-years-old) at repair were independent risk factors for second reoperation. Group B surgical approaches had higher RV-PA systolic pressure gradient at discharge (P=0.02) and required more PA bifurcation repair at the time of second reoperation (P=0.05). Freedom from second reoperation for conduit obstruction was significantly higher in Group A patients at 5 and 8 years (P<0.04) and those with xenografts rather than homograft (P=0.04). CONCLUSIONS: Our results support the optimal surgical approach for RV-PA conduit obstruction is total replacement with a xenograft. RV outflow reconstruction by other techniques without complete dissection of PA bifurcation does not completely relieve the stenosis and could cause early restenosis. Higher systolic gradients at discharge and younger age at first reoperation are predictors of earlier reoperation.     

Treatment of a narrow, single tooth edentulous area with mini-dental implants: a clinical report.

The narrowing of an extraction site often becomes problematic when attempting to restore the space with a conventional wide-diameter implant. A woman is presented who was treated with a square head, mini-dental implant-supported fixed denture for a maxillary with a narrowed edentulous area, with a mesiodistal width of 5 mm. The implant, with a diameter of 2.4 mm, was inserted without reflecting the mucoperiosteal flap and was loaded immediately. During 12 months of follow-up, there has been no bone resorption and no inflammation observed around the implant. In conclusion, in terms of both clinical and aesthetic criteria, small diameter, mini-dental implants can be successfully used as an alternative to treatment with fixed partial dentures.     

A methodological approach to the classification of dermoscopy images.

In this paper a methodological approach to the classification of pigmented skin lesions in dermoscopy images is presented. First, automatic border detection is performed to separate the lesion from the background skin. Shape features are then extracted from this border. For the extraction of color and texture related features, the image is divided into various clinically significant regions using the Euclidean distance transform. This feature data is fed into an optimization framework, which ranks the features using various feature selection algorithms and determines the optimal feature subset size according to the area under the ROC curve measure obtained from support vector machine classification. The issue of class imbalance is addressed using various sampling strategies, and the classifier generalization error is estimated using Monte Carlo cross validation. Experiments on a set of 564 images yielded a specificity of 92.34% and a sensitivity of 93.33%.     

Histological comparison of implanted cadaveric and porcine dermal matrix grafts.

OBJECTIVES: Histological comparison of human-based (AlloDerm) and porcine-based (ENDURAGen) dermal matrices regarding tissue incorporation and neovascularization as potential soft tissue augmentation materials. STUDY DESIGN: In vivo, rat model. METHODS: Subcutaneous implantation of 1-mm thick, 1 cm x 1 cm pieces of AlloDerm, ENDURAGen, and meshed ENDURAGen was performed in 24 Sprague Dawley rats. Implant materials were harvested at 4 (n = 12) and 8 weeks (n = 12). Histological quantification of soft tissue ingrowth and microvascular density was performed following hematoxylin-eosin staining and CD34 immunohistochemistry, respectively. RESULTS: AlloDerm showed significantly greater soft tissue ingrowth and microvascular density compared with both ENDURAGen and meshed ENDURAGen at 4 and 8 weeks (P < 0.001). CONCLUSIONS: Although these results may differ in human host tissues, AlloDerm seems to be a more suitable dermal matrix implant than ENDURAGen for cases in which tissue incorporation and neovascularization are sought for the optimal outcome based on this animal model.     

Effect of hydrocortisone succinate on growth of Chlamydia pneumoniae in vitro.

We examined the effect of hydrocortisone succinate on the growth of three isolates of Chlamydia pneumoniae in vitro. There was a significant increase in the number of inclusions seen in two of the C. pneumoniae strains in the presence of hydrocortisone. There was no significant increase in the number of inclusions with various concentrations of hydrocortisone over time. The addition of hydrocortisone did not affect the in vitro activities of azithromycin, erythromycin, and doxycycline against C. pneumoniae.     

In vivo mammalian brain imaging using one- and two-photon fluorescence microendoscopy

One of the major limitations in the current set of techniques available to neuroscientists is a dearth of methods for imaging individual cells deep within the brains of live animals. To overcome this limitation, we developed two forms of minimally invasive fluorescence microendoscopy and tested their abilities to image cells in vivo. Both one- and two-photon fluorescence microendoscopy are based on compound gradient refractive index (GRIN) lenses that are 350-1,000 microm in diameter and provide micron-scale resolution. One-photon microendoscopy allows full-frame images to be viewed by eye or with a camera, and is well suited to fast frame-rate imaging. Two-photon microendoscopy is a laser-scanning modality that provides optical sectioning deep within tissue. Using in vivo microendoscopy we acquired video-rate movies of thalamic and CA1 hippocampal red blood cell dynamics and still-frame images of CA1 neurons and dendrites in anesthetized rats and mice. Microendoscopy will help meet the growing demand for in vivo cellular imaging created by the rapid emergence of new synthetic and genetically encoded fluorophores that can be used to label specific brain areas or cell classes.     

Linear regression of eye velocity on eye position and head velocity suggests a common oculomotor neural integrator

The oculomotor system produces eye-position signals during fixations and head movements by integrating velocity-coded saccadic and vestibular inputs. A previous analysis of nucleus prepositus hypoglossi (nph) lesions in monkeys found that the integration time constant for maintaining fixations decreased, while that for the vestibulo-ocular reflex (VOR) did not. On this basis, it was concluded that saccadic inputs are integrated by the nph, but that the vestibular inputs are integrated elsewhere. We re-analyze the data from which this conclusion was drawn by performing a linear regression of eye velocity on eye position and head velocity to derive the time constant and velocity bias of an imperfect oculomotor neural integrator. The velocity-position regression procedure reveals that the integration time constants for both VOR and saccades decrease in tandem with consecutive nph lesions, consistent with the hypothesis of a single common integrator. The previous evaluation of the integrator time constant relied upon fitting methods that are prone to error in the presence of velocity bias and saccades. The algorithm used to evaluate imperfect fixations in the dark did not account for the nonzero null position of the eyes associated with velocity bias. The phase-shift analysis used in evaluating the response to sinusoidal vestibular input neglects the effect of saccadic resets of eye position on intersaccadic eye velocity, resulting in gross underestimates of the imperfections in integration during VOR. The linear regression method presented here is valid for both fixation and low head velocity VOR data and is easy to implement.     

Removal of hydrosalpinges increases endometrial leukaemia inhibitory factor (LIF) expression at the time of the implantation window

BACKGROUND: The presence of hydrosalpinges is associated with lower implantation and pregnancy rates in women undergoing IVF-embryo transfer, while salpingectomy improves these parameters. Although the mechanism by which hydrosalpinges affects fertility is not entirely understood, an adverse effect on endometrial receptivity has been postulated. In this study, we hypothesized that the adverse effects of hydrosalpinges on fertility may be in part mediated by inappropriate endometrial expression of leukaemia inhibitory factor (LIF), a cytokine implicated in implantation. METHODS: In order to test our hypothesis, we prospectively examined the expression of LIF during the window of implantation in the endometrium of infertile women (n = 10) with hydrosalpinges prior to and following salpingectomy and of fertile controls (n = 10) by Western blotting and immunohistochemistry. RESULTS: LIF expression was significantly lower in infertile women with hydrosalpinges compared with fertile controls (P < 0.05). Salpingectomy resulted in an increase in LIF expression in eight out of 10 women with hydrosalpinges. LIF levels were increased by 231 +/-49% (mean +/- SEM) following salpingectomy. Immunohistochemical analysis confirmed the Western blot findings. The increased LIF immunoreactivity was predominantly localized to luminal and glandular epithelial cells. CONCLUSIONS: Our findings suggest that observed benefit from salpingectomy in infertile women with hydrosalpinges may be in part mediated by the up-regulation of endometrial LIF expression.     

Lipoxygenase-3 (ALOXE3) and 12(R)-lipoxygenase (ALOX12B) are mutated in non-bullous congenital ichthyosiform erythroderma (NCIE) linked to chromosome 17p13.1.

We report the identification of mutations in lipoxygenase-3 (ALOXE3) and 12(R)-lipoxygenase (ALOX12B) genes in non-bullous congenital ichthyosiform erythroderma (NCIE) linked to chromosome 17. Linkage disequilibrium analysis of six families affected by NCIE permitted us to reduce a recently reported interval of 8.4 cM on chromosome 17p13.1 to a 600 kb region around the marker D17S1796, which contains LOX genes. LOX products have long been implicated in skin disorders. Two point mutations and one deletion were found in ALOXE3 and three point mutations were found in ALOX12B in these consanguineous families from the Mediterranean basin. ALOXE3 and ALOX12B are two genes which are physically linked and functionally related. They are separated by 38 kb, have one more exon than the other LOX genes and are mainly expressed in epithelial cells including keratinocytes. Although the main substrate(s) of the two enzymes is (are) still unknown, the products of ALOX12B obtained in experimental systems have been demonstrated to be of R-chirality. It seems likely that the product of one of these enzymes may be the substrate of the other, and that they belong to the same metabolic pathway.