Comparison of three techniques for decellularization of porcine bone-tendon-bone grafts.

Anterior cruciate ligament injuries are frequent afflictions related to sports or physical trauma. Autograft reconstruction strategies cause secondary injury to the patient. One alternative, supported by clinical evidence, is porcine xenografts. For clinical use, xenografts must be conditioned to avoid immune rejection. The most widely accepted procedure is tissue decellularization. We analyzed three decellularization strategies: the application of the anionic detergent sodium dodecyl sulfate (SDS), sonication, and freezing and thawing cycles. The treated tissues were evaluated histologically using H&E, Masson's trichrome, Verhoeff-van Gieson staining, and DAPI for fluorescent staining of nuclei. Finally, collagen fiber preservation was evaluated by quantifying this protein by colorimetry. The most efficient decellularization techniques were sonication and SDS. Collagen fibers were preserved in all experimental conditions.

Histopathological, ultrastructural, and biochemical traits of apoptosis induced by peroxisomicine A1 (toxin T-514) from Karwinskia parvifolia in kidney and lung.

Peroxisomicine A1 (PA1) is a toxin isolated from the Karwinskia genus plants whose target organs are the liver, kidney, and lung. In vitro studies demonstrated the induction of apoptosis by PA1 in cancer cell lines, and in vivo in the liver. Apoptosis has a wide range of morphological features such as cell shrinkage, plasma membrane blistering, loss of microvilli, cytoplasm, and chromatin condensation, internucleosomal DNA fragmentation, and formation of apoptotic bodies that are phagocytized by resident macrophages or nearby cells. Early stages of apoptosis can be detected by mitochondrial alterations. We investigated the presence of apoptosis in vivo at the morphological, ultrastructural, and biochemical levels in two target organs of PA1: kidney and lung. Sixty CD-1 mice were divided into three groups (n = 20): untreated control (ST), vehicle control (VH), and PA1 intoxicated group (2LD50). Five animals of each group were sacrificed at 4, 8, 12, and 24 h post-intoxication. Kidney and lung were examined by morphometry, histopathology, ultrastructural, and DNA fragmentation analysis. Pre-apoptotic mitochondrial alterations were present at 4 h. Apoptotic bodies were observed at 8 h and increased over time. TUNEL positive cells were detected as early as 4 h, and the DNA ladder pattern was observed at 12 h and 24 h. The liver showed the highest value of fragmented DNA, followed by the kidney and the lung. We demonstrated the induction of apoptosis by a toxic dose of PA1 in the kidney and lung in vivo. These results could be useful in understanding the mechanism of action of this compound at toxic doses in vivo.

Peroxisomicine A1 (toxin T-514) induces cell death of hepatocytes in vivo by triggering the intrinsic apoptotic pathway.

Karwinskia parvifolia possesses the highest concentration levels of the anthracenone T-514 (PA1). Studies have demonstrated the induction of apoptosis by PA1 in cancer cell lines. The aim was to investigate the effects of PA1 on the apoptosis of the mouse liver in vivo and its underlying pathway. Sixty CD-1 mice were divided into three groups: untreated, vehicle, and treated with PA1. The animals were euthanized at 4, 8, 12, and 24 h post-treatment. To confirm the toxic effect of PA1 we determined the activity of catalase. Liver sections were prepared for morphological examination and for immunohistochemical evaluation of anti and pro-apoptotic markers. DNA fragmentation was detected by TUNEL assay and electrophoresis. Pre-apoptotic mitochondrial alterations and cytochrome c oxidase activity were analyzed by transmission electron microscopy. PA1 induced pre-apoptotic mitochondrial alterations, a high activity of the cytochrome oxidase, and apoptosis in hepatocytes. PA1 caused p53 over-expression and down regulation of PCNA. PA1 also increased the expression levels of the pro-apoptotic markers Bax and Bak, whereas the anti-apoptotic molecule Bcl-2 was decreased. PA1 induces apoptosis by activating the intrinsic mitochondrial apoptotic pathway. These results will be useful for studies regarding the use of PA1 as an antineoplastic agent.

In vivo pathogenicity of Trichosporon asahii isolates with different in vitro enzymatic profiles in an immunocompetent murine model of systemic trichosporonosis.

Trichosporon asahii is an opportunistic yeastlike fungus that colonizes the gastrointestinal and respiratory tracts and human skin. Although it is an important cause of disseminated infections by non-Candida species, there are a few reports related to its virulence factors and their possible role in in vivo pathogenicity. We developed a murine model of disseminated trichosporonosis in immunocompetent mice for the evaluation of the in vivo pathogenicity of 6 T. asahii isolates with different in vitro virulence factor profiles. Tissue fungal burden was determined on days 1, 3, 7, 15, and 25 post-challenge. Overall, the largest fungal load was detected in the kidney on the 5 experimental days, while brain, spleen, and liver displayed a comparatively low fungal count. We observed a fungal burden decrease in most experimental groups from day 15. Histological analysis showed the presence of T. asahii in tissue and a generalized inflammatory infiltrate of polymorphonuclear cells in the kidney, liver, red pulp of the spleen, and the hippocampus. Even though our isolates showed different in vitro virulence factors profiles, we did not detect relevant differences when assayed in vivo, except for a higher persistence of a protease- and biofilm-producing strain in kidney, liver, and brain.

Comparative Pathogenicity of Lomentospora prolificans (Scedosporium prolificans) Isolates from Mexican Patients.

We identified 11 Lomentospora prolificans isolates recovered from Mexican patients using phenotypic and molecular characteristics. The identification of isolates was assessed by internal transcribed spacer (ITS rDNA) sequencing. In vitro susceptibility to amphotericin B, fluconazole, voriconazole, posaconazole, caspofungin, anidulafungin and micafungin was determined according to Clinical and Laboratory Standards Institute (CLSI) procedures. Three isolates (07-2239, 11-2242 and 04-2673) were used to induce systemic infection in immunocompetent ICR mice. Survival and tissue burden studies were used as markers of pathogenicity. All of the strains were resistant to every antifungal tested with MIC's for AmB (8->8 µg/ml), VRC (16->16 µg/ml), PSC (16->16 µg/ml), FLC (64->64 µg/ml) and echinocandins with MICs ≥8 µg/ml. One hundred, ninety and sixty percent of the infected mice with the strains 07-2239, 11-2242 and 04-2673 died during the study, respectively. Regarding tissue burden, the highest fungal load of the infected mice was detected in brain followed by spleen and kidney, regardless of the strain.

Ketamine reduces intestinal injury and inflammatory cell infiltration after ischemia/reperfusion in rats.

PURPOSE: Intestinal ischemia reperfusion (I/R) induces severe injury and significant mortality. New therapeutic interventions are needed; ketamine is an anesthetic with anti-inflammatory properties, which has shown protective effects on I/R in various organs. This study investigated effects of ketamine on intestinal I/R injury. METHODS: Male Wistar rats underwent either sham surgery or 30 min of intestinal ischemia followed by 60 min reperfusion. Ketamine pretreatment was administered by intraperitoneal injections at doses of 100, 50, 12.5, or 6.25 mg/kg. The intestinal morphology, mucosal damage, leukocyte infiltration, serum P-selectin, serum intracellular adhesion molecule-1 (ICAM-1), serum antithrombin-III (ATIII), and myenteric ganglion cell structure were evaluated. RESULTS: Intestinal I/R led to severe mucosal damage, leukocyte (especially neutrophil) infiltration, P-selectin and ICAM-1 elevations, ATIII depletion, and myenteric ganglion cell morphological alterations. The ketamine dose dependently diminished these alterations (except for ICAM-1 serum levels), reaching statistical significance at 100, 50, and 12.5 mg/kg. CONCLUSIONS: Ketamine protects the intestine against I/R injury. Ketamine anesthesia has been recommended for clinical situations of sepsis and hemodynamic instability, both frequent during intestinal I/R. The clinical application of ketamine in situations of intestinal I/R warrants consideration.

Ketamine and the myenteric plexus in intestinal ischemia/reperfusion injury.

BACKGROUND AND AIMS: Intestinal ischemia/reperfusion (I/R) is a common clinical entity with severe consequences. We studied the effects of ketamine and the participation of the myenteric plexus in I/R injury. METHODS: Rats were divided into six groups: sham, IR (30 min ischemia/60 min reperfusion), KET+IR (50 mg/kg i.p. ketamine injection before I/R), DEN (myenteric plexus ablated with benzalkonium chloride (BAC) and sham operation performed), DEN+IR (BAC treated and I/R induced), and DEN+KET+IR (BAC treated, ketamine administered, and I/R induced). Serum concentrations of p-selectin, intracellular adhesion molecule-1 (ICAM-1), and antithrombin III (ATIII) were measured, and tissue samples were obtained for histological analysis. RESULTS: IR group had higher intestinal mucosa injury and elevated serum concentrations of ICAM-1 and p-selectin, as well as ATIII depletion, compared with sham group (P < 0.05). In KET+IR group these alterations were significantly reduced (P < 0.05). DEN group showed ICAM-1 elevations when compared with sham group (P < 0.05), and DEN+IR group showed no difference in any parameter compared with IR group. However, ketamine administration in group DEN+KET+IR had no effect on any parameter when compared with DEN+IR group. CONCLUSIONS: Ketamine was able to diminish alterations induced by I/R. Myenteric plexus ablation with BAC treatment alone had no effects on intestinal I/R injury. However, this procedure abolished ketamine's protective effects. Ketamine seems to require an intact enteric nervous system to exert its protective action.