Prion protein ablation increases cellular aggregation and embolization contributing to mechanisms of metastasis

Cellular Prion Protein (PrP(C)) is a cell surface protein highly expressed in the nervous system, and to a lesser extent in other tissues. PrP(C) binds to the extracellular matrix laminin and vitronectin, to mediate cell adhesion and differentiation. Herein, we investigate how PrP(C) expression modulates the aggressiveness of transformed cells. Mesenchymal embryonic cells (MEC) from wildtype (Prnp(+/+)) and PrP(C)-null (Prnp(0/0)) mice were immortalized and transformed by co-expression of ras and myc. These cells presented similar growth rates and tumor formation in vivo. When injected in the tail vein, PrnP(0/0)raS/myc cells exhibited increased lung colonization compared with Prnp(+/+)ras/myc cells. Additionally, Prnp(0/0)ras/myc cells form more aggregates with blood components than Prnp(+/+)ras/myc cells, facilitating the arrest of Prnp(0/0)ras/myc cells in the lung vasculature. Integrin alpha(v)beta(3) is more expressed and activated in MEC and in transformed Prnp(0/0) cells than in the respective Prnp(+/+) cells. The blocking of integrin alpha(v)beta(3) by RGD peptide reduces lung colonization in transformed Prnp(0/0) cells to similar levels of those presented by transformed Prnp(+/+) cells. Our data indicate that PrP(C) negatively modulates the expression and activation of integrin alpha(v)beta(3) resulting in a more aggressive phenotype. These results indicate that PrP(C) may have main implications in modulating metastasis formation. (C) 2009 UICC

Organ-Sparing Microsurgical Resection of Incidental Testicular Tumors Plus Microdissection for Sperm Extraction and Cryopreservation in Azoospermic Patients: Surgical Aspects and Technical Refinements

INTRODUCTION The management of nonpalpable testicular masses is a challenging task, and coexisting infertility can further complicate the treatment decisions. We present our technique for microsurgical organ-sparing resection of incidental nonpalpable testicular nodules combined with microdissection for testicular sperm extraction and tissue cryopreservation in azoospermic patients. TECHNICAL CONSIDERATIONS Five infertile patients with azoospermia presented with nonpalpable hypoechoic testicular masses that were detected by Ultrasonography and underwent organ-sparing surgery. The testis was delivered through an inguinal incision, and the blood circulation was interrupted with a vascular clamp placed on the spermatic cord. Sludged ice was used to prevent warm ischemia, and a temperature probe was used to control the temperature at 12 degrees-15 degrees C. Real-time reflex ultrasonography was used to locate the tumor, and a stereotaxic hook-shaped needle was inserted under ultrasound guidance. The needle was placed adjacent to the tumor to guide the microsurgical resection. The tunica albuginea was incised over the tumor, which was dissected and removed, along with the adjoining parenchymal tissue. Frozen section studies were performed and, if malignancy was confirmed, biopsies of the tumor cavity margins and remaining parenchyma were obtained to ensure the absence of residual tumor. Microdissection was performed for excision of selected enlarged tubules that were processed and cryopreserved. CONCLUSIONS We present a technique for microsurgical organ-sparing resection of testicular tumor and sperm extraction that can be used in selected infertile patients with azoospermia in whom incidental masses have been diagnosed by ultrasonography. This conservative approach should be especially considered for patients with a solitary testis or bilateral tumors. UROLOGY 73: 887-892, 2009. (C) 2009 Elsevier Inc.

Egr transcription factors in the nervous system

The Egr proteins, Egr-1, Egr-2, Egr-3 and Egr-4, are closely related members of a subclass of immediate early gene-encoded, inducible transcription factors. They share a highly homologous DNA-binding domain which recognises an identical DNA response element. In addition, they have several less-well conserved structural features in common. As immediate early proteins, the Egr transcription factors are rapidly induced by diverse extracellular stimuli within the nervous system in a discretely controlled manner. The basal expression of the Egr proteins in the developing and adult rat brain and the induction of Egr proteins by neurotransmitter analogue stimulation, physiological mimetic and brain injury paradigms is reviewed. We review evidence indicating that Egr proteins are subject to tight differential control through diverse mechanisms at several levels of regulation. These include transcriptional, translational and posttranslational (including glycosylation, phosphorylation and redox) mechanisms and protein-protein interaction. Ultimately the differentially co-ordinated Egr response may lead to discrete effects on target gene expression. Some of the known target genes of Egr proteins and functions of the Egr proteins in different cell types are also highlighted. Future directions for research into the control and function of the different Egr proteins are also explored. (C) 1997 Elsevier Science Ltd.

Cutaneous manifestations of thrombophilia

The aim of this article is to review the hypercoagulable states (thrombophilia) most probably found by dermatologists; their cutaneous signs including livedo racemosa, skin necrosis, digital ischemia and ulcerations, retiform purpura and leg ulcers; their appropriate treatment; to describe the skin manifestations that require laboratory tests for thrombophilias and the tests indicated in these clinical conditions.

Microcirculatory effects of local and remote ischemic preconditioning in supraceliac aortic clamping

Introduction: Supraceliac aortic clamping in major vascular procedures promotes splanchnic ischemia and reperfusion (I/R) injury that may induce endothelial dysfunction, widespread inflammation, multiorgan dysfunction, and death. We tested the hypothesis that local or remote ischemic preconditioning (IPC) may be protective against injury after supraceliac aortic clamping through the modulation of mesenteric leukocyte-endothelial interactions, as evaluated with intravital microscopy and expression of adhesion molecules. Methods: Fifty-six male Wistar rats (weight, 190 to 250 g), were divided into four groups of 14 rats each: control sham surgery without aortic occlusion; I/R through supraceliac aortic occlusion for 20 minutes, followed by 120 minutes of reperfusion; local IPC through supraceliac aortic occlusion for two cycles of 5 minutes of ischemia and 5 minutes of reperfusion, followed by the same protocol of the IR group; remote IPC through infrarenal aortic occlusion for two cycles of 10 minutes of ischemia and 10 minutes of reperfusion, followed by the same protocol of the IR group. Seven animals per group were used to evaluate in vivo leukocyte-endothelial interactions in postcapillary venules with intravital microscopy and another seven animals per group were used to collect mesentery samples for inmmnohistochemistry demonstration of adhesion molecules expression. Results: Supraceliac aortic occlusion increased the number of rolling leukocytes with slower velocities and increased the number of adherent leukocytes to the venular surface and leukocyte migration to the interstitium. The expression of P-selectin, E-selectin, and intercellular adhesion molecule-1 was also increased significantly after I/R. Local or remote IPC reduced the leukocyte recruitment in vivo and normalized the expression of adhesion molecules. Conclusions: Local or remote IPC reduces endothelial dysfunction on mesenteric microcirculation caused by I/R injury after supraceliac aortic clamping. (J Vase Surg 2010;52:1321-9.) Clinical Relevance: The present study demonstrates that ischemia and reperfusion injury induced by supraceliac aortic occlusion promotes endothelial dysfunction and leukocyte recruitment on mesenteric microcirculation. Local and remote preconditioning reduced leukocyte-endothelial interactions and normalized the expression of endothelial adhesion molecules involved in this process. Although we recognize the limitation of an experimental model, our findings suggest that local and remote ischemic preconditioning minimize the endothelial dysfunction and leukocyte recruitment events that play a central role in systemic inflammation and multiorgan dysfunction after major aortic reconstructions.

Role of nitric oxide in hyperpnea-induced bronchoconstriction and airway microvascular permeability in guinea pigs

The present study aimed to evaluate the role of nitric oxide (NO) on hyperpnea-induced bronchoconstriction (HIB) and airway microvascular hyperpermeability (AMP). Sixty-four guinea pigs were anesthetized, tracheotonnized, cannulated, and connected to animal ventilator to obtain pulmonary baseline respiratory system resistance (Rrs). Animals were then submitted to 5 minutes hyperpnea and Rrs was evaluated during 15 minutes after hyperpnea. AMP was evaluated by Evans blue dye (25 mg/kg) extravasation in airway tissues. Constitutive and inductible NO was evaluated by pretreating animals with N(G)-nitro-1-arginine methyl ester (I-NAME) (50 mg/kg), aminoguadinine (AG) (50 mg/kg), and I-arginine (100 mg/kg) and exhaled NO (NOex) was evaluated before and after drug administration and hyperpnea. The results show that I-NAME potentiated (57%) HIB and this effect was totally reversed by I-arginine pretreatment, whereas AG did not have effect on HIB. I-NAME decreased basal AMP (48%), but neither I-NAME nor AG had any effect on hyperpnea-induced AMP. NOex levels were decreased by 50% with I-NAME, effect that was reversed by I-arginine treatment. These results suggest that constitutive but not inducible NO could have a bronchoprotective effect on HIB in guinea pigs. The authors also observed that neither constitutive nor inducible NO seems to have any effect on hyperpnea-induced AMP.

Experimental multivisceral xenotransplantation

Background: Organ shortage impairs the proposition of multivisceral transplantation to treat multiple organ failure. Interspecies (xeno) transplantation is a valid solution for organ shortage; however, suitable models of this advance are lacking. We describe an effective model of multivisceral xenotransplantation to study hyperacute rejection. Methods: Under general anesthesia, we in block recovered the distal esophagus, stomach, small bowel, colon, liver, pancreas, spleen, and kidneys from donors and implanted heterotopically in the lower abdomen of recipients. Animals were divided into four groups: I-canine donor, swine recipient (n = 6); II - swine donor, canine recipient (n = 5); III-canine donor, canine recipient (n = 4); and IV-swine donor, swine recipient (n = 5). Groups I and 11 comprised experimental (xenotransplantation) and III and IV control groups (allotransplantation). During the experiment, we appraised recipient evolution and graft modification by sequential biopsy up to 3 h. At this time, we killed animals for autopsy (experimental end point). Results: We accomplished all experiments successfully. Every grafts attained customary appearance and convenient urine output immediately after unclamp. Around 15 min after reperfusion, xenografts achieved signs of progressive hyperacute rejection and absence of urine output. At the end of experiments we observed moderate to severe hyperacute rejection at small bowel, colon, mesenteric lymph node, liver, spleen, pancreas, and kidney, while stomach and esophagus achieved mild lesions. In contrast, allograft achieved normal or minimum ischemia/reperfusion injury and constant urine output. Conclusion: The present procedure assembles a simple and effective model to study multivisceral xenotransplantation and may ultimately spread researches toward hyperacute rejection.

Differential expression of Egr-1-like DNA-binding activities in the naive rat brain and after excitatory stimulation

Egr-1 and related proteins are inducible transcription factors within the brain recognizing the same consensus DNA sequence. Three Egr DNA-binding activities were observed in regions of the naive rat brain. Egr-1 was present in all brain regions examined. Bands composed, at least in part, of Egr-2 and Egr-3 were present in different relative amounts in the cerebral cortex, striatum, hippocampus, thalamus, and midbrain. All had similar affinity and specificity for the Egr consensus DNA recognition sequence. Administration of the convulsants NMDA, kainate, and pentylenetetrazole differentially induced Egr-1 and Egr-2/3 DNA-binding activities in the cerebral cortex, hippocampus, and cerebellum. All convulsants induced Egr-1 and Egr-2 immunoreactivity in the cerebral cortex and hippocampus. These data indicate that the members of the Egr family are regulated at different levels and may interact at promoters containing the Egr consensus sequence to fine tune a program of gene expression resulting from excitatory stimuli.

Narrowed lumen of the right coronary artery in chronic chagasic patients is associated with ischemic lesions of segmental thinnings of ventricles

Thinning of myocardial segments, mainly at the apex and basal posterior region of left ventricle, are frequent lesions in chronic chagasic cardiopathy (CCC), but still without a well determined etiology. Previously we found severe myocardial microvascular dilatation that could cause ischemia in watershed regions. In this study we analyzed whether narrowness in epicardial coronary arteries in CCC might explain these thinned ventricular lesions. Two groups of dilated hearts with similar weights were compared: eleven hearts from patients with CCC versus four hearts from patients with dilated cardiomyopathy (IDCM). As normal controls we studied three non dilated normal weight hearts. There were no atherosclerotic plaques in the main branches of epicardial coronary arteries and cross-sectional luminal areas of proximal and distal segments were histologically measured. It was found that CCC hearts presented a lower mean luminal area in the right coronary artery (RCA) branch than IDCM, in proximal (4.3 +/- 1.4 vs 6.6 +/- 2.0 mm(2); p = 0.02) and in distal (1.6 +/- 1.0 vs 3.4 +/- 0.9 mm(2); p = 0.01) segments, with no statistical differences with normal hearts (2.7 +/- 1.3 and 1.5 +/- 0.3 mm(2)) in proximal (p = 0.2) and distal (p = 0.11) sections. In conclusion thinning of ventricular wall in CCC patients seems to be ischemic lesions in the peripheral territory irrigated by the right coronary artery, possibly due to a steal phenomenon by the left coronary, induced by micro vessels dilatation.

Potentializing the effects of GM1 by hyperbaric oxygen therapy in acute experimental spinal cord lesion in rats

Study design: Experimental, controlled, animal study. Objectives: To evaluate the effect of GM1 ganglioside, hyperbaric oxygen and both in combination, in the treatment of experimental spinal cord lesions in rats. Setting: Brazil. Methods: Thirty-two Wistar rats with spinal cord lesions were divided into four groups: one group received GM1 ganglioside, one was submitted to hyperbaric oxygen therapy (HBOT), the third received both treatments and the fourth received no treatment (control). Results: There were no significant differences between the groups in the histological analysis, for any of the variables (necrosis, hemorrhage, hyperemia, cystic degeneration, P>0.06). Neither were there any significant differences in the comparison of left and right sides in the functional tests (P>0.06 for all). No significant differences were found in the locomotor ratings, in the comparison of groups at 2, 7, 21 and 28 days after the surgical procedure. However, in the evaluation on day 14, group 3, which received the combined therapy, showed a significantly higher Basso Beattie and Bresnahan score than the other groups (P = 0.015). Conclusion: The therapeutic effect of GM1 in locomotor evaluation of rats submitted to spinal cord lesion is anticipated by HBOT. Spinal Cord (2010) 48, 808-813; doi:10.1038/sc.2010.37; published online 27 April 2010

Changes in plasma free fatty acid levels in septic patients are associated with cardiac damage and reduction in heart rate variability

Free fatty acids (FFAs) have been shown to produce alteration of heart rate variability (HRV) in healthy and diabetic individuals. Changes in HRV have been described in septic patients and in those with hyperglycemia and elevated plasma FFA levels. We studied if sepsis-induced heart damage and HRV alteration are associated with plasma FFA levels in patients. Thirty-one patients with sepsis were included. The patients were divided into two groups: survivors(n = 12) and nonsurvivors (n = 19). The following associations were investigated: (a) troponin I elevation and HRV reduction and (b) clinical evolution and HRV index, plasma troponin, and plasma FFA levels. Initial measurements of C-reactive protein and gravity Acute Physiology and Chronic Health Evaluation scores were similar in both groups. Overall, an increase in plasma troponin level was related to increased mortality risk. From the first day of study, the nonsurvivor group presented a reduced left ventricular stroke work systolic index and a reduced low frequency (LF) that is one of HRV indexes. The correlation coefficient for LF values and troponin was r(2) = 0.75 (P < 0.05). All patients presented elevated plasma FFA levels on the first day of the study (5.11 +/- 0.53 mg/mL), and this elevation was even greater in the nonsurvivor group compared with the survivors (6.88 +/- 0.13 vs. 3.85 +/- 0.48 mg/mL, respectively; P < 0.05). Cardiac damage was confirmed by measurement of plasma troponin I and histological analysis. Heart dysfunction was determined by left ventricular stroke work systolic index and HRV index in nonsurvivor patients. A relationship was found between plasma FFA levels, LFnu index, troponin levels, and histological changes. Plasma FFA levels emerged as possible cause of heart damage in sepsis.

Anti-Inflammatory Effects of Peritoneal Lavage in Acute Pancreatitis

Objectives: Intraperitoneal administration of trypsin stimulates the production of cytokines from peritoneal macrophages. Removing the pancreatitis-associated ascitic fluid from the peritoneal cavity may decrease the systemic inflammatory response in acute pancreatitis (AP). We investigated the effect of peritoneal lavage on the systemic inflammatory response in severe AP. Methods: Acute pancreatitis was induced in Wistar rats by 5% taurocholate intraductal injection. Peritoneal lavage was performed for 4 hours after onset of AP. At 4 hours after induction of AP, serum samples were assayed for amylase and inflammatory cytokines (tumor necrosis factor alpha, interleukin-6 [IL-6], and IL-10). Expression of pancreatic cyclooxygenase-2 and inducible nitric oxide synthase, liver mitochondrial function, and pulmonary myeloperoxidase activities were determined. Results: Peritoneal lavage after AP led to a decrease in serum levels of tumor necrosis factor alpha and IL-6 and an increase in IL-10. In the pancreas, this treatment reduced cyclooxygenase-2 and inducible nitric oxide synthase expression. Liver mitochondrial dysfunction was also reduced. There were no differences on serum amylase levels and pulmonary myeloperoxidase between groups with AP. Conclusions: Peritoneal lavage has a systemic anti-inflammatory effect in severe AP and may be able to decrease the severity of severe AP.

Influence of coronary artery disease assessment and treatment in the incidence of cardiac events in renal transplant recipients

Background: The best strategy for pre-transplant investigation and treatment of coronary artery disease (CAD) is controversial. Methods: We evaluated 167 renal transplant recipients before transplantation to determine the incidence of cardiac events and death. We performed clinical evaluations and myocardial scans in all patients and coronary angiography in select patients. Results: Asymptomatic patients with normal myocardial scans (n = 57) had significantly fewer cardiac events (log-rank = 0.0002) and deaths (log-rank = 0.0005) than did patients with abnormal scans but no angiographic evidence of CAD (n = 76) and individuals with CAD (n = 34) documented angiographically. CAD increased the probability of events (HR = 2.27, % CI 1.007-5.11; p = 0.04). The incidence of cardiac events (log-rank = 0.349) and deaths (log-rank = 0.588) was similar among patients treated medically (n = 23) or by intervention (n = 11). Conclusion: Asymptomatic patients with normal myocardial scans had a better cardiac prognosis than did patients with or without CAD and positive for myocardial ischemia. Patients with altered scan and CAD had the poorer outcome. Guideline-oriented medical treatment is safe and yields results comparable to coronary intervention in renal transplant patients with CAD. The data do not support pre-emptive myocardial revascularization for renal transplant candidates.

Role of p21 and oxidative stress on renal tubular resistance after acute ischaemic injury

Background. Subsequent ischaemic episodes may induce renal resistance. P21 is a cell cycle inhibitor that may be induced by oxygen-free radicals and may have a protective effect in ischaemic acute kidney injury (AKI). This study aimed at evaluating the role of oxidative stress and p21 on tubular resistance in a model of acquired resistance after renal ischaemia and in isolated renal tubules. Methods. Wistar rats were divided into: Group 1-sham; Group 2-sham operated and after 2 days submitted to 45-min ischaemia; and Group 3-45-min ischaemia followed after 2 days by a second 45-min ischaemia. Plasma urea was evaluated on Days 0, 2 and 4. Serum creatinine, creatinine clearance and oxidants (thiobarbituric acid-reactive substances) were determined 48 h after the second procedure (Day 4). Histology, immunohistochemistry for lymphocytes (CD3), macrophages (ED1), proliferation (PCNA) and apoptosis (TUNEL) were also evaluated. Rat proximal tubules (PTs) were isolated by collagenase digestion and Percoll gradient from control rats and rats previously subjected to 35 min of ischaemia. PTs were submitted to 15-min hypoxia followed by 45-min reoxygenation. Cell injury was assessed by lactate dehydrogenase release and hydroperoxide production (xylenol orange). Results. Ischaemia induced AKI in Group 2 and 3 rats. Subsequent ischaemia did not aggravate renal injury, demonstrating renal resistance (Group 3). Renal function recovery was similar in Group 2 and 3. Plasma and urine oxidants were similar among in Group 2 and 3. Histology disclosed acute tubular necrosis in Group 2 and 3. Lymphocyte infiltrates were similar among all groups whereas macrophages infiltrate was greater in Group 3. Cell proliferation was greater in Group 2 compared with Group 3. Apoptosis was similar in groups 2 and 3. The p21 expression was increased only in Group 3 whereas it was similar in groups 1 and 2. PTs from the ischaemia group were sensitive to hypoxia but resistant to reoxygenation injury which was followed by lower hydroperoxide production compared to control PT. Conclusion. Renal resistance induced by ischaemia was associated with cell mechanism mediators involving oxidative stress and increased p21 expression.

Changes in Perfusion-Weighted Magnetic Resonance Imaging after Carotid Angioplasty with Stent

Carotid artery stenosis due to arteriosclerosis increases the risk of cerebral ischemia via embolic phenomena or reduced blood flow. The changes in cerebral perfusion that may occur after treatment are not clearly understood. This study evaluated the changes in cerebral microcirculation following carotid angioplasty with stenting (CAS) under cerebral protection with filters using ultrafast gradient echo (GRE) perfusion weighted imaging (PWI) with magnetic resonance imaging (MRI). Prospectively, 21 cervical carotid stenosis patients, mean age 69.95 years, underwent MRI 12 h before and 72 h after CAS. PWI parameters were collected for statistical analysis: cerebral blood volume (CB V), mean transit time (MTT) and time to peak (TTP). Statistical analysis was applied to absolute parameters and to values normalized against those from the contralateral parenchyma. The main finding of this study was improved hemodynamics for the normalized data after CAS, shown by reduced MTT (p<0.001) and TTP (p=0.019) in the territory fed by the middle cerebral artery ipsilateral to the CAS. Absolute data showed increased blood volume in the cerebral hemispheres after CAS, which was more accentuated on the stent side (p=0.016) than the contralateral side (p=0.029). Early improvements in cerebral perfusion, mainly seen in the normalized data, were clearly demonstrated in the timing parameters - TTP & MTT - after CAS.