Postmortem redistribution of THC in the pig.

To improve the knowledge of the postmortem redistribution of Δ(9)-tetrahydrocannabinol (THC), an animal model using the Large White pig has been developed, whereby 15 pigs received an intravenous injection of THC (200 µg/kg body weight) and were euthanized 2 h after administration. An autopsy was performed on three pigs immediately after being euthanized while the others were stored in supine position at ambient temperature for 6, 15, 24, or 48 h. THC concentration in blood from the vena cava decreased after death whereas left or right cardiac blood concentrations increased. No blood specimens collected from different sites of the carcasses adequately reflected the perimortem THC concentrations. The highest concentrations of THC at anytime were observed in lung tissue, and brain tissue seemed to present the most stable concentrations over time. This study can assist toxicologists in determining which specimens can, most appropriately, be used for interpretation of cannabinoid concentrations in postmortem specimens.

Endotoxin tolerance enhances interleukin-10 renal expression and decreases ischemia-reperfusion renal injury in rats.

The potential implication of interleukin (IL) 6, tumor necrosis factor alpha (TNF-alpha), and IL-10 in the protective effect of low-dose lipopolysaccharide (LPS) administration against renal ischemia-reperfusion injury was evaluated in a rat model. Eighteen male Sprague-Dawley rats were injected intravenously with either 0.5 mg/kg of LPS (tolerant group) or saline (control group) 2 days before surgery. Ischemic renal injury was induced by clamping the left renal artery for 60 min on rats immediately after right-side nephrectomy. Reperfusion was obtained by clamp removal and was studied at R0 (no reperfusion), 2H (R2), and 24H (R24) by renal tubular disorder characterization and by plasma creatinine as well as renal cytokine (IL-6, IL-10, and TNF-alpha) studies. No differences were observed between the two groups as concerns the period immediately after renal ischemia (R0). The endotoxin-tolerant group was associated with a significantly lower creatinine level at R24 (231 +/- 28 vs 315 +/- 36 micromol/L; P = 0.007). Pretreatment with LPS significantly reduced the degree of proximal tubule necrosis and outer medulla congestion. In such tolerant animals, renal IL-6 production was decreased, whereas IL-10 production was significantly increased at R2 and R24. There were no differences in TNF-alpha renal production. In this study, we demonstrated that administration of low doses of LPS to rats had a protective effect from renal reperfusion injury, and our data suggest that IL-10 might play a role in this phenomenon.

Modulation of peripheral-type benzodiazepine receptor during ischemia reperfusion injury in a pig kidney model: a new partner of leukemia inhibitory factor in tubular regeneration.

BACKGROUND: It was demonstrated that postischemic kidney expresses different factors in a pattern that recapitulates expression of these factors in the developing kidney. We investigated whether peripheral-type benzodiazepine receptor (PBR), which belongs to the mitochondrial permeability transition pore and is essential during development, could be influenced by the ischemia-reperfusion injury process when compared with leukemia inhibitor factor (LIF). STUDY DESIGN: PBR, LIF, and LIF receptor messengers and proteins were analyzed in adult normal and ischemic kidney under conditions mimicking cardiac arrest: 18 pigs were studied after 60 minutes of warm ischemia and reperfusion for 7 days and compared with sham-operated (Sham, n = 12) and control (CONT, n = 12) groups. The same messengers and proteins were assessed in fetal kidneys. RESULTS: In normal kidney, PBR was expressed in descending and ascending limbs of Henle and in distal tubules. After ischemia-reperfusion injury, PBR mRNA significantly increased between days 1 and 7 in cortex and outer medulla. PBR protein increased between days 1 and 7, and was transiently expressed in proximal tubules at days 1 and 3 and returned to basal level at day 7. LIF messenger and protein increased rapidly at day 1 in proximal tubules. In turn, LIF receptor messenger and protein were not changed during reperfusion. CONCLUSIONS: These results suggest that PBR may be implicated in ischemia-reperfusion injury and, particularly, in the regenerative process within proximal tubules with LIF. These new insights open the possibility of novel targets for organ protection and repair.

Free radical generation of protease-resistant prion after substitution of manganese for copper in bovine brain homogenate.

The exchange between copper and seven transition metals is studied in a bovine brain obex homogenate according to the redox status of the medium. In reductive conditions, almost all the studied metals can substitute for copper when it is in the reduced form Cu+. This substitution is reversible, since copper uptake as Cu++ is restored in an oxidizing medium but only Co++, Ni++ and Mn++, in this decreasing order, can substitute perfectly for copper in bovine brain homogenate. To study free radical effects on bovine brain proteins, at first a copper substitution was processed in order to inhibit superoxide dismutase-like protective properties against free radicals in copper metalloproteins. Manganese was selected since a brain copper decrease correlated with a manganese increase is well-known in transmissible spongiform encephalopathies. Results for bovine brain homogenate, initially negative in the Western blot Prionics test, indicate that the substitution of manganese for copper in a reducing medium and exposure to UVA-induced free radicals produce proteinase K resistant prion. These findings suggest that an impairment in brain metal homeostasis leading to oxidative abnormalities may be involved in transmissible spongiform encephalopathies.

Validation of Large White Pig as an animal model for the study of cannabinoids metabolism: application to the study of THC distribution in tissues.

This study presents a new animal model, the Large White Pig, which was tested for studying cannabinoids metabolism. The first step has focused on determination of plasma kinetics after injection of Delta(9)-tetrahydrocannabinol (THC) at different dosages. Seven pigs received THC by intravenous injections (50, 100 or 200 microg/kg). Plasma samples were collected during 48 h. Determination of cannabinoids concentrations were performed by gas chromatography/mass spectrometry. Results showed that plasma kinetics were comparable to those reported in humans. Terminal half-life of elimination was 10.6 h and a volume of distribution of 32 l/kg was calculated. In a second step, this model was used to determine the kinetic profile of cannabinoids distribution in tissues. Eight Large White male pigs received an injection of THC (200 microg/kg). Two pigs were sacrificed 30 min after injection, two others after 2, 6 and 24 h. Different tissues were sampled: liver, kidney, heart, lung, spleen, muscle, fat, bile, blood, vitreous humor and several brain areas. The fastest THC elimination was noted in liver tissue, where it was completely eliminated in 6 h. THC concentrations decreased in brain tissue slower than in blood. The slowest THC elimination was observed for fat tissue, where the molecule was still present at significant concentrations 24 h later. After 30 min, THC concentration in different brain areas was highest in the cerebellum and lowest in the medulla oblongata. THC elimination kinetics noted in kidney, heart, spleen, muscle and lung were comparable with those observed in blood. 11-Hydroxy-THC was only found at high levels in liver. THC-COOH was less than 5 ng/g in most tissues, except in bile, where it increased for 24 h following THC injection. This study confirms, even after a unique administration, the prolonged retention of THC in brain and particularly in fat, which could be at the origin of different phenomena observed for heavy users such as prolonged detection of THC-COOH in urine or cannabis-related flashbacks. Moreover, these results support the interest for this animal model, which could be used in further studies of distribution of cannabinoids in tissues.

Inhibition of coagulation proteases Xa and IIa decreases ischemia-reperfusion injuries in a preclinical renal transplantation model.

Coagulation is an important pathway in the pathophysiology of ischemia-reperfusion injuries. In particular, deceased after circulatory death (DCD) donors undergo a no-flow period, a strong activator of coagulation. Hence, therapies influencing the coagulation cascade must be developed. We evaluated the effect of a new highly specific and effective anti-Xa/IIa molecule, with an integrated innovative antidote site (EP217609), in a porcine preclinical model mimicking injuries observed in DCD donor kidney transplantation. Kidneys were clamped for 60 minutes (warm ischemia), then flushed and preserved for 24 hours at 4°C in University of Wisconsin (UW) solution (supplemented or not). EP217609-supplemented UW solution (UW-EP), compared with unfractionated heparin-supplemented UW solution (UW-UFH) or UW alone (UW). A mechanistic investigation was conducted in vitro: addition of EP217609 to endothelial cells during hypoxia at 4°C in the UW solution inhibited thrombin generation during reoxygenation at 37°C in human plasma and reduced tumor necrosis factor alpha, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 messenger RNA cell expressions. In vivo, function recovery was markedly improved in the UW-EP group. Interestingly, levels of thrombin-antithrombin complexes (reflecting thrombin generation) were reduced 60 minutes after reperfusion in the UW-EP group. In addition, 3 months after transplantation, lower fibrosis, epithelial-mesenchymal transition, inflammation, and leukocyte infiltration were observed. Using this new dual anticoagulant, anti-Xa/IIa activity during kidney flush and preservation is protected by reducing thrombin generation at revascularization, improving early function recovery, and decreasing chronic lesions. Such an easy-to-deploy clinical strategy could improve marginal graft outcome.

Influence of colloid, preservation medium and trimetazidine on renal medulla injury.

In organ transplantation, preservation injury is an important factor which could influence short-term and long-term graft outcome. The renal medulla is particularly sensitive to oxidant stress and ischemia-reperfusion injury (IRI). Using an autotransplant pig kidney model, we investigated renal function and medullary damage determined between day 1 and week 2 after 24- or 48-h cold storage in different preservation solutions: University of Wisconsin solution (UW), Hopital Edouard Herriot solution (a high Na+ version of UW), ECPEG (high Na+ preservation solution with PEG) and ICPEG (a high K+ version of ECPEG) with or without trimetazidine (TMZ). TMZ improved renal preservation and increased renal function when added in each preservation solution (particularly HEH and ECPEG). Medullary damage led to the early appearance of trimethylamine-N-oxide (TMAO) followed by 1H-NMR in urine and plasma. TMZ and ECPEG is the most efficient association to reduce medullary damage. This study clarifies the role of colloid and polarity solution and the role of mitochondrial protection by TMZ.

Resistance in vitro to low-dose aspirin is associated with platelet PlA1 (GP IIIa) polymorphism but not with C807T(GP Ia/IIa) and C-5T Kozak (GP Ibalpha) polymorphisms.

OBJECTIVES: We investigated whether three platelet gene polymorphisms, Pl(A1/A2), C807T, and C-5T Kozak (encoding, respectively, for platelet membrane glycoproteins (GP) IIIa, GP Ia/IIa, GP Ibalpha), could contribute to the resistance to a low dose of aspirin (160 mg/day). BACKGROUND: Aspirin antiplatelet effect is not uniform in all patients, and the mechanism by which some patients are in vitro resistant to aspirin remains to be determined. However, it has been suggested that polymorphisms of platelet membrane glycoproteins might contribute to aspirin resistance. METHODS: Ninety-eight patients on aspirin (160 mg/day) for at least one month were enrolled. Aspirin resistance was measured by the platelet function analyzer (PFA)-100 analyzer; genotyping of the three polymorphisms was performed using a polymerase chain reaction-based restriction fragment-length polymorphism analysis. RESULTS: Using a collagen/epinephrine-coated cartridge on the PFA-100, the prevalence of aspirin resistance was 29.6% (n = 29). Aspirin-resistant patients were significantly more often Pl(A1/A1) (86.2%; n = 25) than sensitive patients (59.4%; n = 41; p = 0.01). Of the 29 patients, 25 were reevaluated after having taken 300 mg/day aspirin for at least one month. Only 11 patients still have nonprolonged collagen epinephrine closure time, and these were all Pl(A1/A1). No relation was found between resistance status and C-5T Kozak or C807T genotypes. CONCLUSIONS: Platelets homozygous for the Pl(A1) allele appear to be less sensitive to inhibitory action of low-dose aspirin. This differential sensitivity to aspirin may have potential clinical implications whereby specific antiplatelet therapy may be best tailored according to the patient's Pl(A) genotype.

Cyclooxygenase 1-dependent production of F2-isoprostane and changes in redox status during warm renal ischemia-reperfusion.

The detrimental role of oxidative stress has been widely described in tissue damage caused by ischemia-reperfusion. A nonenzymatic, reactive oxygen species-related pathway has been suggested to produce 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)), an epimer of prostaglandin F(2alpha) (PGF(2alpha)), which has been proposed as an indicator of oxidative stress. Using an in vivo ischemia-reperfusion model in rat kidneys, we investigated intrarenal accumulation of 8-iso-PGF(2alpha) and PGF(2alpha). Both prostanoids accumulated in the ischemic kidney and disappeared upon reperfusion. In addition, a nonselective (acetylsalicylic acid) or selective cyclooxygenase (COX) 1 inhibitor (SC-560) completely abrogated the 8-iso-PGF(2alpha) and PGF(2alpha) formation in kidneys subjected to ischemia. COX2 inhibition had no effect on the production of these prostanoids. Therefore the two metabolites of arachidonic acid seemed to be produced via an enzymatic COX1-dependent pathway. Neither COX overexpression nor COX activation was detected. We also investigated renal glutathione, which is considered to be the major thiol-disulfide redox buffer of the tissue. Total and oxidized glutathione was decreased during the ischemic period, whereas no further decrease was seen for up to 60 min of reperfusion. These data demonstrate that a dramatic decrease in antioxidant defense was initiated during warm renal ischemia, whereas the 8-iso-PGF(2alpha) was related only to arachidonate conversion by COX1.

Evidence for a protective role of trimetazidine during cold ischemia: targeting inflammation and nephron mass.

Ischemia-reperfusion injury (IRI) is associated with an increased risk of acute rejection, delayed graft function, or chronic graft dysfunction. Mitochondria plays a central role in this process. Using an autotransplant pig kidney model, changes in renal function and morphology were determined after different periods of cold ischemia in kidneys preserved in the University of Wisconsin solution (UW), high-Na(+) version of UW (HEH) or Celsior (CEL) a newly developed high-Na(+) solution, with or without trimetazidine (TMZ). Kidney function was better preserved in HEH after 24 hr and particularly 48- and 72-hr cold storage than in CEL and UW. TMZ improved the preservation quality when added to the different solutions tested, particularly after 48- and 72-hr cold storage. Interstitial fibrosis and tubular atrophy were reduced in HEH with TMZ. CD4(+) T-cell infiltration was also modulated by the preservation conditions. Peripheral-type benzodiazepine receptor (PBR) positive cells infiltration was also modulated by preservation conditions. TMZ was efficient to reduce IRI when added in the various preservation solutions. These results suggest that protection of the mitochondrial function should be a major target to limit IRI. In addition, this study outlines the role of CD4(+) T cells and PBR expression in inflammatory responses after IRI.

Gender difference and sex hormone production in rodent renal ischemia reperfusion injury and repair.

BACKGROUND: Several lines of evidence suggest a protective effect of female sex hormones in several organs subjected to ischemia-reperfusion injury. The aim of the study was to investigate sex hormone production in male rats after a renal ischemia-reperfusion sequence and analyze the influence of gender differences on tissue remodelling during the recovery process. METHOD: Age-matched sexually mature male and female rats were subjected to 60 min of renal unilateral ischemia by pedicle clamping with contralateral nephrectomy and followed for 1 or 5 days after reperfusion. Plasma creatinine, systemic testosterone, progesterone and estradiol levels were determined. Tubular injury, cell proliferation and inflammation, were evaluated as well as proliferating cell nuclear antigen, vimentin and translocator protein (TSPO) expressions by immunohistochemistry. RESULTS: After 1 and 5 days of reperfusion, plasma creatinine was significantly higher in males than in females, supporting the high mortality in this group. After reperfusion, plasma testosterone levels decreased whereas estradiol significantly increased in male rats. Alterations of renal function, associated with tubular injury and inflammation persisted during the 5 days post-ischemia-reperfusion, and a significant improvement was observed in females at 5 days of reperfusion. Proliferating cell nuclear antigen and vimentin expression were upregulated in kidneys from males and attenuated in females, in parallel to injury development. TSPO expression was transiently increased in proximal tubules in male rats. CONCLUSIONS: After ischemia, renal function recovery and tissue injury is gender-dependent. These differences are associated with a modulation of sex hormone production and a modification of tissue remodeling and proliferative cell processes.

Polyethylene glycols interact with membrane glycerophospholipids: is this part of their mechanism for hypothermic graft protection?

Polyethylene glycol (PEG), a high-molecular-weight colloid present in new organ preservation solutions, protects against cold ischemia injuries leading to better graft function of transplanted organs. This protective effect cannot be totally explained by immuno-camouflaging property or signaling-pathway modifications. Therefore, we sought for an alternative mechanism dependent on membrane fluidity. Using the Langmuir-Pockles technique, we show here that PEGs interacted with lipid monolayers of defined composition or constituted by a renal cell lipid extract. High-molecular-weight PEGs stabilized the lipid monolayer at low surface pressure. Paradoxically, at high surface pressure, PEGs destabilized the monolayers. Hypothermia reduced the destabilization of saturated monolayer whereas unsaturated monolayer remained unaffected. Modification of ionic strength and pH induced a stronger stabilizing effect of PEG 35,000 Da which could explain its reported higher effectiveness on cold-induced injuries during organ transplantation. This study sheds a new light on PEG protective effects during organ preservation different from all classical hypotheses.

Direct thrombin inhibitor prevents delayed graft function in a porcine model of renal transplantation.

BACKGROUND: Kidney transplantations from donors after cardiac arrest (DCA) are characterized by an increase in the occurrence of delayed graft function and primary nonfunction. In this study, Melagatran, a selective reversible direct thrombin inhibitor was used to limit renal injury in a DCA pig kidney transplantation model. METHODS: We used a porcine model of DCA to study the effects of treatment with Melagatran in the peri-conservation period. Thromboelastography was used to check Melagatran antithrombin effect on in vitro clot formation. Reverse-transcriptase polymerase chain reaction was used to analyze the peripheral immune cells activation status. Renal function and morphologic study were performed at days 1 and 7. Finally, we analyzed the mechanisms of Melagatran protection on kidney microvasculature primary endothelial cells. RESULTS: Prolongation of coagulation time (Ex-Tem) was observed 10 min after injection; however, Melagatran did not modulate increases of thrombin-antithrombin complexes following reperfusion. Melagatran significant treatment lowered the proinflammatory status of circulating immune cells. Animal's survival was increased in Melagatran-treated groups (9 of 10 in Melagatran groups vs. 4 of 10 in controls at day 7). Renal injury and inflammation were also significantly reduced in treated groups. We also demonstrated a direct protective effect of Melagatran against endothelial cell activation and inflammation in vitro. CONCLUSION: Direct thrombin inhibitor administration in the periconservation period improved graft outcome and reduced renal injury in a model of DCA.

A p38 mitogen-activated protein kinase inhibitor protects against renal damage in a non-heart-beating donor model.

Ischemia-reperfusion injury is one of the central nonimmunologic processes involved in renal allograft dysfunction. Kidneys from non-heart beating donors (NHBD) exhibit higher rates of delayed graft function (DGF) than those from other donors. Primary nonfunction and DGF are the main barriers to the use of kidneys from NHBD. Using a pig model of NHBD transplantation, we studied the effect of FR167653 (a p38 MAP kinase inhibitor) on the recovery and reparation of kidneys exposed to both warm (WI: 1 h) and cold ischemia (24 h). Our results demonstrate that the addition of FR167653 increases the kinetics of proximal tubule cell regeneration after 60 min of WI. Hypoxia-inducible factor and vascular endothelial growth factor expression was also more important in FR167653-treated kidneys compared with those in nontreated groups. Also, expression of peripheral-type benzodiazepine receptor, involved in tissue repair, was increased in the FR167653-treated groups. At 3 mo, the protective effects of FR167653 were accompanied by a reduction of long-term inflammation process and tubulointerstitial fibrosis development associated with a limitation of ischemia-induced remodeling. This study suggests that such treatment may be useful in protocols aimed at improving the quality of renal transplants from NHBD. In addition, the beneficial role of FR167653 in limiting early injury is associated with secondary reduction in development of tubular atrophy and interstitial fibrosis which are together the hallmark of failing renal transplants. The more efficient effect was observed when FR167653 was added in combination before WI, during cold storage and reperfusion.

Comparison of protective effects of trimetazidine against experimental warm ischemia of different durations: early and long-term effects in a pig kidney model.

Acute renal failure (ARF) is often the consequence of an ischemia-reperfusion injury (IRI) and associated with high mortality. Warm ischemia (WI) is a crucial factor of tissue damage, and tissue destruction led by ischemia-reperfusion (I/R) can impact the early and long-term functional outcome. Trimetazidine (TMZ) is an anti-ischemic drug. Previously, we already verified its protective effect on a cold-ischemic pig kidney model by directly adding TMZ into the preservation solution (Faure JP, Baumert H, Han Z, Goujon JM, Favreau F, Dutheil D, Petit I, Barriere M, Tallineau C, Tillement JP, Carretier M, Mauco G, Papadopoulos V, Hauet T. Biochem Pharmacol 66: 2241-2250, 2003; Faure JP, Petit I, Zhang K, Dutheil D, Doucet C, Favreau F, Eugene M, Goujon JM, Tillement JP, Mauco G, Vandewalle A, Hauet T. Am J Transplant 4: 495-504, 2004). In this study, we aimed to study the potential effect of TMZ pretreatment (5 mg/kg iv 24 h before WI) on the injury caused by WI for 45, 60, and 90 min and reperfusion in a WI pig kidney model. Compared with sham-operated (control) and uninephrectomized animals (UNX), TMZ pretreatment significantly reduced deleterious effects after 45 min, and particularly 60 and 90 min, of WI by improving the recovery of renal function and minimizing the inflammatory response commonly prevalent in ischemic kidney injury. Compared with controls (control group and UNX group), it was observed that 1) hypoxia-inducible factor-1 (HIF-1alpha) expression occurred earlier and with a higher intensity in the TMZ-treated groups; 2) the reduction of IRI during the first week following reperfusion was correlated with an earlier and greater expression of stathmin, which is involved in the process of tubular repair; and 3) the tubulointerstitial fibrosis was reduced, particularly after 60 and 90 min of WI. In conclusion, TMZ made the warm-ischemic kidneys more resistant to the deleterious impact of a single episode of I/R and reduced early and long-term subsequent damage.

Lack of correlation between nutritional status and seroprotection against influenza in a long term care facility.

UNLABELLED: We conducted a prospective study in a long-term care facility. Virologic diagnosis was assessed using viral isolation, polymerase chain reaction and serology for all patients with a flu-like syndrome. Albumin, vitamins and trace elements were also measured. RESULTS: The risk of influenza increased 6.5-fold in patients with an antibody titer of 40 during the influenza outbreak (P=0.04). Micronutrients and vitamins deficiencies were important. Patients with antibody titer >1:40 could still be infected by the virus without correlation with the nutritional status. CONCLUSION: Humoral protection with a titer >1:40 might not be protective in the elderly. Nutritional deficiencies were too prevalent to detect any effect on the results.

Cloning, sequencing, and chromosomal localization of pig peripheral benzodiazepine receptor: three different forms produced by alternative splicing.

We report the molecular cloning of the cDNA sequence for pig peripheral benzodiazepine receptor (PBR) by using RT-PCR and 5'/3' terminal extension. Three different transcripts (long, middle, and short) are identified. The open reading frame (ORF) of the longest PBR mRNA encodes a deduced polypeptide of 169 amino acids with a calculated molecular weight of 18,609 Da and an estimated pI of 9.70, which corresponds to the authentic PBR of other mammalian species. The middle transcript (PBR-M) contains a 141-codon ORF, which is consistent with that of the authentic PBR, but lacks a region of 84 bp so that its encoded polypeptide lacks a region of 28 amino acids from 35 to 62 of the authentic PBR polypeptide. The short transcript (PBR-S) contains a 104-codon ORF, which overlaps that of the authentic PBR, but lacks a region of 211 bp so that its encoded polypeptide lacks a region of 65 amino acids of the N-terminal of the authentic PBR. The pig PBR gene was mapped to the telomeric end of SSC5p. In addition, PBR mRNA was the more abundant detected form in pig tissues and in warm kidney that underwent ischemia suggesting functional implications of PBR during the renal repair process.

Gender differences in vascular reactivity of aortas from rats with and without portal hypertension.

BACKGROUND: Inflammatory responses related to portal hypertension may be different in male and female rats. Most experimental studies of portal hypertension have involved male animals, and little information is available on gender differences in this setting. The aim of the present study was to compare aortic reactivity in female and male rats with and without portal hypertension. METHODS: Contraction response curves to phenylephrine were studied with aortic rings, with and without endothelium. For relaxation studies, rings were precontracted with phenylephrine 10(-7) mol/L and then exposed to acetylcholine 10(-4) mol/L. Portal hypertension was provoked by calibrated portal stenosis performed 2 weeks before experiments. RESULTS: In non-hypertensive conditions, the contractile response to increasing phenylephrine concentrations was significantly stronger in rings from male than female rats, both with and without endothelium. In male rats with portal hypertension, the phenylephrine concentration-response curves were lowered and shifted to the right in aortic rings both with and without endothelium. In female rats, portal hypertension did not induce significant changes in the phenylephrine concentration-response curves. In female rats, portal hypertension induced a marked increase in relaxation (157 +/- 123% vs 81 +/- 64% in controls); the increase was also stronger than that in male rats with portal hypertension (95 +/- 6%; P < 0.01). CONCLUSION: Clear gender differences were observed in vasoconstrictor responsiveness of aortic rings from rats with and without portal hypertension. Contrary that in male rats, portal hypertension did not induce vascular hyporesponsiveness in female rats. Further investigations are required to explain these differences.

A rapid and specific whole blood HPA-1 phenotyping by flow cytometry using two commercialized monoclonal antibodies directed against GP IIIa and GP IIb-IIIa complexes.

The human platelet antigen 1 (HPA-1) system has been implicated in rare but severe diseases, such as neonatal alloimmune thrombocytopenic purpura, post-transfusion purpura and immune platelet refractoriness. We developed a flow cytometry assay for HPA-1 phenotyping using two commercial monoclonal antibodies, P2 and SZ21, directed against glycoprotein (GP) IIb-IIIa and GP IIIa respectively. One hundred and twenty-seven healthy controls were studied and ratios of mean fluorescence intensity for P2 and SZ21 discriminated between HPA-1a homozygotes and heterozygotes. These two monoclonal antibodies, coupled with flow cytometry represent a rapid and reliable tool for platelet HPA-1 typing to aid diagnosis.

Polyethylene glycol reduces early and long-term cold ischemia-reperfusion and renal medulla injury.

Ischemia-reperfusion injury (IRI) after transplantation is a major cause of delayed graft function, which has a negative impact on early and late graft function and improve acute rejection. We have previously shown that polyethylene glycol (PEG) and particularly PEG 20M has a protective effect against cold ischemia and reperfusion injury in an isolated perfused pig and rat kidney model. We extended those observations to investigate the role of PEG using different doses (30g or 50g/l) added (ICPEG30 or ICPEG50) or not (IC) to a simplified preservation solution to reduce IRI after prolonged cold storage (48-h) of pig kidneys when compared with Euro-Collins and University of Wisconsin solutions. The study of renal function and medulla injury was performed with biochemical methods and proton NMR spectroscopy. Histological and inflammatory cell studies were performed after reperfusion (30-40 min) and on days 7 and 14 and weeks 4, 8, and 12. Peripheral-type benzodiazepine receptor (PBR), a mitochondrial protein involved in cholesterol homeostasis, was also studied. The results demonstrated that ICPEG30 improved renal function and reduced medulla injury. ICPEG30 also improved tubular function and strongly protect mitochondrial integrity. Post-IRI inflammation was strongly reduced in this group, particularly lymphocytes TCD4(+), PBR expression was influenced by IRI in the early period and during the development of chronic dysfunction. This study clearly shows that PEG has a beneficial effect in renal preservation and suggests a role of PBR as a marker IRI and repair processes.