In Vitro Generation of Atrioventricular Heart Valve Neoscaffolds

Tissue engineering of cardiovascular structures represents a novel approach to improve clinical strategies in heart valve disease treatment. The aim of this study was to engineer decellularized atrioventricular heart valve neoscaffolds with an intact ultrastructure and to reseed them with umbilical cord‐derived endothelial cells under physiological conditions in a bioreactor environment. Mitral (n = 38) and tricuspid (n = 36) valves were harvested from 40 hearts of German Landrace swine from a selected abattoir. Decellularization of atrioventricular heart valves was achieved by a detergent‐based cell extraction protocol. Evaluation of the decellularization method was conducted with light microscopy and quantitative analysis of collagen and elastin content. The presence of residual DNA within the decellularized atrioventricular heart valves was determined with spectrophotometric quantification. The described decellularization regime produced full removal of native cells while maintaining the mechanical stability and the quantitative composition of the atrioventricular heart valve neoscaffolds. The surface of the xenogeneic matrix could be successfully reseeded with in vitro‐expanded human umbilical cord‐derived endothelial cells under physiological flow conditions. After complete decellularization with the detergent‐based protocol described here, physiological reseeding of the xenogeneic neoscaffolds resulted in the formation of a confluent layer of human umbilical cord‐derived endothelial cells. These results warrant further research toward the generation of atrioventricular heart valve neoscaffolds on the basis of decellularized xenogeneic tissue.     

The HIV 5′ Gag Region Displays a Specific Nucleotide Bias Regulating Viral Splicing and Infectivity

Alternative splicing and the expression of intron-containing mRNAs is one hallmark of HIV gene expression. To facilitate the otherwise hampered nuclear export of non-fully processed mRNAs, HIV encodes the Rev protein, which recognizes its intronic response element and fuels the HIV RNAs into the CRM-1-dependent nuclear protein export pathway. Both alternative splicing and Rev-dependency are regulated by the primary HIV RNA sequence. Here, we show that these processes are extremely sensitive to sequence alterations in the 5’coding region of the HIV genomic RNA. Increasing the GC content by insertion of either GFP or silent mutations activates a cryptic splice donor site in gag, entirely deregulates the viral splicing pattern, and lowers infectivity. Interestingly, an adaptation of the inserted GFP sequence toward an HIV-like nucleotide bias reversed these phenotypes completely. Of note, the adaptation yielded completely different primary sequences although encoding the same amino acids. Thus, the phenotypes solely depend on the nucleotide composition of the two GFP versions. This is a strong indication of an HIV-specific mRNP code in the 5′ gag region wherein the primary RNA sequence bias creates motifs for RNA-binding proteins and controls the fate of the HIV-RNA in terms of viral gene expression and infectivity.     

Systemic lupus erythematosus in three ethnic groups. XX. Damage as a predictor of further damage

OBJECTIVE: To examine the predictors of damage in a multiethnic cohort of systemic lupus erythematosus (SLE) patients with a specific focus on damage at baseline. Patients and METHODS: SLE patients from a multiethnic US (Hispanic, African-American and Caucasian) cohort (LUMINA: Lupus in Minority populations, Nature versus nurture) were included if they had > or =6 months of follow-up in the cohort. Damage was measured with the Systemic Lupus International Collaborating Clinics (SLICC) Damage Index (SDI). The dependent variable was the change in SDI score between study visits. Predictors were from the preceding visit. Variables known to affect damage accrual in SLE were included in the analyses. RESULTS: Three hundred and fifty-two patients (82 Hispanics, 153 African-Americans and 117 Caucasians) representing 1795 patient visits were included. Previous damage was found to be a significant predictor of subsequent damage accrual (P < 0.0001). Other variables predictive of subsequent damage accrual were disease activity (P < 0.0001), older age (P = 0.041) and use of corticosteroids (P = 0.0048). CONCLUSIONS: Once damage occurs in SLE, further damage is expected to occur. This is more likely to be the case if disease activity persists. These data have clinical implications for the management of SLE patients.     

A community-based TB drug susceptibility study in Mimika District, Papua Province, Indonesia.

SETTING: A district level tuberculosis (TB) control programme in Papua Province, Indonesia. OBJECTIVE: To determine the nature and extent of drug-resistant TB in newly diagnosed sputum smear-positive patients. METHODS: Sputum was collected from previously untreated smear-positive pulmonary TB patients diagnosed in the district over a 10-month period. Sputum specimens were processed and inoculated into a BACTEC MGIT960 tube. Isolates were identified by Ziehl-Neelsen staining, hybridisation with nucleic acid probes and biochemical investigations. Susceptibility testing was performed using the radiometric proportion method. Pyrazinamide testing was performed using the Wayne indirect method. RESULTS: One hundred and seven patients had sputum sent to a reference laboratory; 101 (94.4%) were culture-positive for Mycobacterium tuberculosis, with 87 (86.1%) fully sensitive to first-line anti-tuberculosis drugs. Two per cent were multidrug-resistant (MDR-TB) and 12 (11.9%) had other drug resistance. Each of the MDR-TB isolates was susceptible to amikacin, capreomycin, ciprofloxacin and para-aminosalicylic acid (PAS), but were resistant to rifabutin. One isolate was also resistant to ethionamide. CONCLUSIONS: MDR-TB is present in Indonesia but is not a major problem for TB control in this district. Generalisability to other districts in Indonesia, particularly large urban areas, needs to be confirmed by future studies.     

Gut inflammation and expression of ICC in a fetal lamb model of fetoscopic intervention for gastroschisis

Background

The pathogenesis of intestinal dysmotility in gastroschisis is not completely understood. Peel formation and disorganization of interstitial Cajal cells (ICC) have been proposed in humans. The aim of this study was to evaluate the impact of prenatal coverage of gastroschisis on gut inflammation and expression of ICC in a fetal lamb model.

Methods

Twenty-one German blackhead sheep with an abdominal wall defect that was created fetoscopically on day 77 of 145 days gestation were used in this study. Intrauterine surgery with the aim to cover the defect was performed 3 weeks later; two fetuses were covered completely, 5 partially and 11 remained uncovered. Three fetuses without gastroschisis were used as controls. All fetuses were retrieved by cesarean section at day 135. Samples of the small intestine were stained with hematoxylin and eosin for histologic analysis of peel formation and serosal and muscular thickness. For ICC detection, immunohistochemistry using anti-CD117 (c-Kit) antibody was used.

Results

In all samples with exposure to amniotic fluid, peel formation and significantly decreased ICC were found. Complete coverage reduced peel formation and disorganization of ICC compared to uncovered animals almost to the level of controls.

Conclusions

Peel formation and ICC derangement were significantly reduced by prenatal coverage of gastroschisis. Moreover, this animal model mimics the histopathological bowel changes as seen in human gastroschisis and may, therefore, be used for further research on the pathophysiology and fetal therapy of this malformation.     

Melanoma in childhood: An EORTC-MCG multicenter study on the clinico-pathological aspects

Melanoma in children is rare. Nevertheless, it is imperative that clinicians be aware that melanoma does occur in childhood. Yet there is very little information available on the clinico-pathologic variations, and the prognostic parameters of melanoma in children. This report presents the results of a multicenter study of 102 lesions originally diagnosed as cutaneous melanoma, conducted among 5 Western European countries and collected during the period 1961–1994. Criteria for inclusion in the study included: (1) diagnosis of cutaneous melanoma; (2) age up to 16 years at diagnosis; and (3) availability of representative microscopic slides. On the basis of the histologic review only, 60 lesions were confirmed as melanoma, and 42 lesions initially diagnosed as melanoma were reclassified as nevi; 31 of the latter contained a predominance of spindle cells. The only significant parameter associated with the development of metastases or fatal outcome was thickness of more than 2.00 mm. The 5-year survival rate observed in this study was 84%. Based on these findings we conclude that considerable over-diagnosis of melanomas in children occurs. In order, therefore, to give consistent epidemiological data on melanomas in children and to improve proper recognition of their diagnostic features, both by clinicians and by pathologists, we propose to set up a central registry of melanomas in children in Europe, under the auspices of the European Organization for Research and Treatment of Cancer. © 1996 Wiley-Liss, Inc.     

Sub-angiographic peripheral emboli in high resolution DWI after endovascular recanalization

Journal of Neurology - To analyze the incidence of peripheral emboli after successful mechanical thrombectomy (MT) of intracranial large vessel occlusions (LVO). We performed a prospective analysis...     

Ischemic stroke and dose adjustment of oral Factor Xa inhibitors in patients with atrial fibrillation

Journal of Neurology - Oral Factor Xa inhibitors for the prevention of stroke in atrial fibrillation require dose adjustment based on certain clinical criteria, but the off-label use of the reduced...