Strut protrusion and shape impact on endothelial shear stress: insights from pre-clinical study comparing Mirage and Absorb bioresorbable scaffolds

Protrusion of scaffold struts is related with local coronary flow dynamics that can promote scaffold restenosis and thrombosis. That fact has prompted us to investigate in vivo the protrusion status of different types of scaffolds and their relationship with endothelial shear stress (ESS) distributions. Six Absorb everolimus-eluting Bioresorbable Vascular Scaffolds (Absorb, Abbott Vascular) and 11 Mirage sirolimus-eluting Bioresorbable Microfiber Scaffolds (Mirage, Manli Cardiology) were implanted in coronaries of eight mini pigs. Optical coherence tomography (OCT) was performed post-scaffold implantation and obtained images were fused with angiographic data to reconstruct the three dimensional coronary anatomy. Blood flow simulation was performed and ESS distribution was estimated for each scaffold. Protrusion distance was estimated using a dedicated software. Correlation between OCT-derived protrusion and ESS distribution was assessed for both scaffold groups. A significant difference was observed in the protrusion distances (156?±?137 µm for Absorb, 139?±?153 µm for Mirage; p?=?0.035), whereas difference remained after adjusting the protrusion distances according to the luminal areas. Strut protrusion of Absorb is inversely correlated with ESS (r?=??0.369, p?<?0.0001), whereas in Mirage protrusion was positively correlated with EES (r?=?0.192, p?<?0.0001). Protrusion distance was higher in Absorb than in Mirage. The protrusion of the thick quadratic struts of Absorb has a tendency to lower shear stress in the close vicinity of struts. However, circular shape of the less thick struts of Mirage didn’t show this trend in creating zone of recirculation around the struts. Strut geometry has different effect on the relationship between protrusion and shear stress in Absorb and Mirage scaffolds.     

INDUCTION OF TUMORS IN DOMESTIC RABBITS WITH NUCLEIC ACID PREPARATIONS FROM PARTIALLY PURIFIED SHOPE PAPILLOMA VIRUS AND FROM EXTRACTS OF THE PAPILLOMAS OF DOMESTIC AND COTTONTAIL RABBITS

A deoxyribonucleic acid preparation which showed infectivity and tumorigenic activity in domestic rabbits was isolated from the papillomatous tissue of wild cottontail rabbits by phenolic deproteinization procedure. The activity of the preparation could be completely abolished by its exposure to a minute amount (0.02 µg/ml) of DNAase. Antisera against Shope papilloma virus did not block the tumorigenic activity of the preparation, and trypsin and chymotrypsin had no effect on it. The extraction with phenol of a partially purified virus preparation also yielded extracts with tumorigenic potency. Extracts obtained from the domestic rabbit papilloma and submitted to phenolic deproteinization also proved infective and tumorigenic in rabbits of this sort, although the level of "tumorigenicity" was much lower than that of the cottontail preparations. Tests for intact virus, carried out with half of the extracts yielded wholly negative findings.     

A strategy for efficient cross-presentation of CTL-epitope peptides leading to enhanced induction of in vivo tumor immunity.

The activation of antitumor cytotoxic T-lymphocytes (CTLs) depends on how efficiently the relevant tumor antigen peptides are delivered into the major histocompatibility complex (MHC) class I presentation pathway in antigen presenting cells (APCs). An elegant approach to promote the peptide-MHC class I association has been described for enhanced peptide transportation into the endoplasmic reticulum (ER) by adding an ER insertion signal sequence (Eriss). Nevertheless, this approach does not appear potent enough to induce in vivo tumor protective immunity. Herein, we present a novel peptide-vaccine strategy based on the combined utilization of Eriss and fusogenic liposomes (FLs) capable of directly introducing encapsulated CTL-epitope peptides into the MHC class I pathway of APCs. APCs pulsed with free peptides, FL-encapsulated peptides, or FL-encapsulated Eriss-conjugated peptides exhibited comparable levels of antigen-presenting activity at early phases after pulsing. Interestingly, whereas in the first two methods the APC ability began to decline 40 to 60 h after pulsing, FL-encapsulated Eriss(+) peptides allowed APCs to retain peptide-presentation activity for at least 140 h. This advantage of FL-encapsulated Eriss(+) peptides correlated with the induction of more potent antitumor immunity compared with soluble Eriss(+) or Eriss(-) peptides or FL-encapsulated Eriss(-) peptides when they were administered in vivo. Thus, Eriss-conjugated CTL-epitope peptides encapsulated in FLs provide a highly efficient tumor-vaccine to enhance the induction of in vivo tumor immunity.     

Paracrine regulation of FSH by follistatin in folliculostellate cell-enriched primate pituitary cell cultures

Primary pituitary cell cultures are an important tool for understanding pituitary hormone gene expression. In the course of study of pituitary cell cultures from nonhuman adult male primates, pituitary secretory cells were noted to be rapidly overgrown by epithelioid cells with the morphological, immunocytochemical, and proliferative characteristics of folliculostellate cells. Using competitive RT-PCR assays, follistatin mRNA levels were found to increase 4-fold as folliculostellate cells proliferated with time in culture, whereas FSH-beta mRNA and FSH secretion were suppressed. Follistatin gene expression was stimulated by activin-A and pituitary adenylate cyclase-activating polypeptide but not by [D-Trp(6)]-GnRH ethylamide. Testosterone (T) also increased follistatin mRNA levels and follistatin protein secretion. FSH-beta mRNA was stimulated by [D-Trp(6)]-GnRH ethylamide and activin but was suppressed by T. The reciprocal relationship between follistatin and FSH-beta mRNA levels as folliculostellate cells proliferate with time in culture implies a role for folliculostellate cells in the follistatin-activin system in primates. The actions of GnRH and T on follistatin and FSH-beta mRNA levels in these cultures were opposite to effects observed in pituitary cultures from rats and identify species differences in the control of FSH production that may be folliculostellate cell-related.     

Sludge and stone formation in the gallbladder in bedridden elderly patients with cerebrovascular disease: influence of feeding method

Purpose. The incidence of gallbladder sludge or gallstone formation in bedridden patients with cerebrovascular disease (CVD) remains obscure. The aim of this study was to determine the incidence, relationship to feeding method, and mechanisms of gallbladder sludge and gallstone formation in elderly patients with CVD. Methods. Using ultrasonography, we determined the development of gallbladder sludge and gallstone over a 12-month period, the area of the gallbladder, the gallbladder contractile response to cerulein, and fasting levels of plasma cholecystokinin (CCK) in 40 bedridden elderly patients with CVD. The patients were divided into three groups based on the feeding method: oral ingestion (OI), nasogastric feeding (NF), and total parenteral nutrition (TPN). Results. Gallbladder sludge and gallstone were not observed in any of the 14 OI patients, but occurred in 6 and 1 of the 11 NF patients, and in 14 and 3 of the 15 TPN patients, respectively. Fasting gallbladder areas were significantly larger in the TPN group than in the other two groups. The TPN group showed a marked decrease in cerulein-induced gallbladder contractility. Fasting plasma CCK levels were lower in the TPN group than in the OI group. Conclusions. Our results indicate that elderly patients with CVD confined to bed over long periods are not necessarily at risk of gallbladder sludge or gallstone formation, and the development of these features may be associated with the feeding method. The predisposition of CVD patients on TPN to gallbladder disease is probably caused by failure of gallbladder contraction, resulting from insufficient secretion of CCK and impaired sensitivity of the gallbladder to CCK. Received: August 1, 2000 / Accepted: December 1, 2000     

Governing step of metastasis visualized in vitro

Metastasis is the ultimate life-threatening stage of cancer. The lack of accurate model systems thwarted studies of the metastatic cell’s basic biology. To follow continuously the succeeding stages of metastatic colony growth, we heritably labeled cells from the human lung adenocarcinoma cell line ANIP 973 with green fluorescent protein (GFP) by transfection with GFP cDNA. Labeled cells were then injected intravenously into nude mice, where, by 7 days, they formed brilliantly fluorescing metastatic colonies on mouse lung [Chishima, T., Miyagi, Y., Wang, X., Yang, M., Tan, Y., Shimada, H., Moossa, A. R. & Hoffman, R. M. (1997) Clin. Exp. Metastasis 15, 547–552]. The seeded lung tissue was then excised and incubated in the three-dimensional sponge-gel-matrix-supported histoculture that maintained the critical features of progressive in vivo tumor colonization while allowing continuous access for measurement and manipulation. Tumor progression was continuously visualized by GFP fluorescence in the same individual cultures over a 52-day period, during which the tumors spread throughout the lung. Histoculture tumor colonization was selective for lung cancer cells to grow on lung tissue, because no growth occurred on histocultured mouse liver tissue, which was also observed in vivo. The ability to support selective organ colonization in histoculture and visualize tumor progression by GFP fluorescence allows the in vitro study of the governing processes of metastasis [Kuo, T.-H., Kubota, T., Watanbe, M., Furukawa, T., Teramoto, T., Ishibiki, K., Kitajima, M., Moossa, A. R., Penman, S. & Hoffman, R. M. (1995) Proc. Natl. Acad. Sci. USA 92, 12085–12089]. The results presented here provide significant, new opportunities to understand and to develop treatments that prevent and possibly reverse metastasis.     

CASE REPORT: Pure Red Cell Aplasia Associated with Parvovirus B19 Infection in a Patient with Ulcerative Colitis

Anemia is a common problem that results from various causes in patients with ulcerative colitis (UC), but there is little information on the association of UC with pure red cell aplasia (PRCA). We describe the first case of parvovirus-induced PRCA in UC. A 28-year-old woman with chronic UC was admitted to the hospital for treatment of active pancolitis. Three courses of pulse therapy with methylprednisolone provided complete remission. However, the patient developed reticulocytopenia and a subsequent fall in hemoglobin to 6.2 g/dl. Bone marrow examination revealed selective aplasia of red cell precursors and giant pronoromoblasts. Enzyme immunoassay identified specific immunoglobulin M antibody against parvovirus B19 in the serum. Based on these findings, the diagnosis of PRCA caused by the virus was made. The patient was treated with a 3-day course of intravenous immunoglobulin (5 g/day), resulting in brisk reticulocytosis, folowed by normalization of hemoglobin level. In conclusion, Chronic or acute blood loss in UC associated with enhanced red cell turnover might be a risk factor for PRCA when affected patients contract parvovirus B19 infection.     

Androgen receptors in gonadotrophs in pituitary cultures from adult male monkeys and rats

There is substantial evidence demonstrating that the principal feedback action of androgens to decrease LH secretion in male primates, including man, is to slow the GnRH pulse generator, whereas in male rats androgens not only decrease GnRH but also suppress LH synthesis and secretion through a direct pituitary effect. Previous experiments in our laboratory revealed that testosterone (T) suppresses LH secretion and decreases alpha-subunit mRNA levels in male rat pituitary cell cultures perifused with pulses of GnRH but not in pituitary cells from adult male monkeys. In the present study, we sought to determine whether the lack of responsiveness of gonadotrophs to androgens in the primate is androgen receptor (AR) related. Primary cultures were prepared from the anterior pituitary glands of adult male monkeys and rats. Cells were identified as gonadotrophs if they were immunoreactive for LH-beta or FSH-beta. Of these cells in the monkey, 80% contained both gonadotropins, 17% contained only LH-beta, and 3% contained only FSH-beta. AR immunoreactivity (IR) was nuclear in 22% and 15%, respectively, of monkey and rat FSH-beta-positive cells in the absence of T. Following T treatment, nuclear AR IR was identified in 79% of monkey and 81% of rat gonadotrophs. T treatment similarly intensified AR IR in mouse gonadotroph alphaT3-1 and LbetaT2 cells and in monkey and rat fibroblasts. Single-cell RT-PCR confirmed coexpression of LH-beta and AR mRNA as well as LH-beta and GH mRNA in monkey gonadotrophs. Our data reveal that most monkey, as well as rat, gonadotrophs are AR-positive with nuclear localization in the presence of T. GH expression is not required for AR expression in gonadotrophs. We conclude that the failure of T to inhibit LH secretion and decrease alpha-subunit mRNA expression in the male primate is not due a disturbance in AR nuclear shuttling.     

Validation of endoscopic 13C-urea breath test with nondispersive infrared spectrometric analysis in the management of Helicobacter pylori infection

BACKGROUND/AIMS: 13C-EUBT (endoscopic 13C-urea breath test), that combines the conventional urea breath test with endoscopy, provides excellent accuracy for detection of H. pylori. Recently, a simpler, less expensive and isotope-selected nondispersive infrared spectrometer has been developed for the urea breath test. We validated the diagnostic performance of 13C-EUBT using nondispersive infrared spectrometer in the management of H. pylori infection. METHODOLOGY: EUBT was performed in 232 patients by first collecting a baseline breath sample followed by upper gastrointestinal endoscopy. A 20-mL aliquot of 13C-urea solution was sprayed over the entire stomach under endoscopic guidance. Breath samples taken 0 and 20 minutes after spraying were analyzed using nondispersive infrared spectrometer. H. pylori infection was assessed by rapid urease test and histology. The cutoff level was determined by a receiver-operating characteristic curve analysis. Forty-four samples were also analyzed by the conventional isotope ratio mass spectrometer to compare results from both analyzers. We also applied the nondispersive infrared spectrometer-based EUBT to evaluate the efficacy of eradication therapy. RESULTS: Employing 2.4 per mL as the best cutoff value, the EUBT yielded an excellent diagnostic accuracy, with a sensitivity of 99% and specificity of 99%. The sensitivity and specificity of the test for assessing eradication therapy were 94% (16/17) and 100% (57/57), respectively. There was a high linear correlation between nondispersive infrared spectrometer and isotope ratio mass spectrometer (r = 0.998, p < 0.0001). CONCLUSIONS: 13C-EUBT using nondispersive infrared spectrometer is a highly accurate and rapid method for the assessment of H. pylori eradication as well as for detecting H. pylori infection. We believe that nondispersive infrared spectrometer gives more rapid and less expensive method for the management of H. pylori infection with the EUBT.