Perinatal asphyxia induces neurogenesis in hippocampus: an organotypic culture study

There is clinical and experimental evidence indicating that neurocircuitries of the hippocampus are vulnerable to hypoxia/ischemia occurring at birth, inducing, upon re-oxygenation/re-circulation, delayed neuronal death, but also compensatory mechanisms, including neurogenesis. In the present report, perinatal asphyxia was induced by immersing foetuses-containing uterine horns removed from ready-to-deliver rats into a water bath at 37 degrees C for 20 min. Some pups were delivered immediately after the hysterectomy to be used as non-asphyxiated caesarean-delivered controls. The pups were sacrificed after seven days for preparing organotypic hippocampal cultures. The cultures were grown on a coverslip in a medium-containing culture tube inserted in a hole of a roller device standing on the internal area of a cell incubator at 35 degrees C, 10% CO2. At days in vitro (DIV) 25-27, cultures were fixed for assaying cell proliferation and neuronal phenotype with antibodies against 5-bromo-2'deoxyuridine (BrdU) and microtubule associated protein-2 (MAP-2), respectively. Confocal microscopy revealed that there was a 2-fold increase of BrdU-positive, but a 40% decrease of MAP-2-positive cells/mm3 in cultures from asphyxia-exposed, compared to that from control animals. Approximately 30% of BrdU-positive cells were also positive for MAP-2 (approximately 4800 cells), mainly seen in the dentate gyrus of the hippocampus, demonstrating a 3-fold increase of postnatal neurogenesis, when the total amount of double-labelled cells seen in cultures from asphyxia-exposed animals is compared to that from control animals.

Protective effects of organosulfur compounds towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay

The aim of this study was to investigate the protective effect of organosulfur compounds towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay. N-Nitrosopyrrolidine (NPYR) and N-nitrosodimethylamine (NDMA) incubated with formamidopyrimidine-DNA glycosylase (Fpg), caused a significant increase in oxidative DNA damage in comparison to the solvent control, the lowest effective concentrations, being 5 and 27 mM, respectively. NPYR exerted greater genotoxic effects than NDMA. None of the organosulfur compounds (OSCs) concentrations tested in presence or absence of Fpg enzyme, caused DNA damage per se. OSCs (diallyl sulfide, DAS and dipropyl sulfide, DPS, 1-50 microM; diallyl disulfide, DADS and dipropyl disulfide, DPDS, 1-5 microM) reduced the genotoxic effects of the N-nitrosamines in a dose-dependent manner when HepG2 cells were simultaneously treated with OSCs and N-nitrosamines. The effect of NPYR was attenuated by about 61-67%, respectively, with the highest concentration of DAS (50 microM) and DADS (5 microM). The protective effect of DADS (5 microM, 66%) was higher than DAS (50 microM, 53%) towards NDMA-induced oxidative DNA damage. A concentration of 50 microM DPS and 5 microM DPDS led to a 65-63% and 59-65% reduction in NPYR/NDMA-induced oxidative DNA damage, respectively. Our results indicate that OSCs protect human-derived cells against the oxidative DNA damaging effect of NPYR and NDMA, two carcinogenic compounds which occur in the environment.

Computed Tomographic Screening of Pulmonary Arterial Hypertension in Candidates for Lung Transplantation

INTRODUCTION

Computed tomography (CT) is essential to evaluate candidates for lung transplantation (LT) We sought to correlate identification of pulmonary arterial hypertension (PAH) via CT to echocardiographic (Eco) and/or hemodynamic observations (Hd) as well as the pathological findings (Path) at posttransplant pneumonectomy.

MATERIALS AND METHODS

The study included 24 consecutive months follow-up of 71 patients who were referred for LT evaluation with 54 undergoing LT. Study parameters included CT [diameter of the principal pulmonary artery (PPA) >or= 29 mm), PPA/diameter of the ascending aorta (AA) ratio > 1; diameter of the lobar artery (LA)/diameter of the lobar bronchiole (LB) ratio > 1 in three or more lobes; thickening of the anterosuperior pericardial recess (>15 mm); mosaic lung density pattern]; PAPs via Eco and/or Hd, and findings Path of PAH. Statistical analysis included chi-square and Pearson correlation coefficient.

RESULTS

Thirty-five patients had PAH. Significant relationships (P < .05) were observed between PAH (Eco and/or Hd) and PPA, PPA/AA, and LA/LB. The sensitivity of the finding PPA >or= 29 mm was 65.9%, and 85.7% when combined with LA/LB > 1. In the Path study, 14/54 patients revealed alterations compatible with PAH. Significant relationships (P < .05) were observed between PAH via Path and PPA (CT) and between PAH via Path and PAH (Eco and/or Hd).

CONCLUSIONS

CT is useful for the detection of PAH. Findings of PAH via CT were indicative of the need for further confirmatory studies. In contrast, the absence of findings with CT does not exclude the possible presence of PAH.

Venous Graft Thrombosis in Patients on Peritoneal Dialysis Before Transplantation

BACKGROUND

It has been described that patients on peritoneal dialysis (PD) suffer from thrombotic events (vascular access, deep venous thrombosis, and graft thrombosis) more frequently after transplantation than other recipients. We analyzed the incidence of allograft thrombosis among patients transplanted in a 6-year period (January 1, 2000, to December 31, 2005) to identify etiological factors, such as inherited thrombophilia.

MATERIALS AND METHODS

We performed 197 renal transplants in 189 patients, including 115 who had been on hemodialysis (HD), 44 on PD, and 30 preemptive. We recorded immunological and demographic data, studied graft and patient survivals, and evaluated the hypercoagulable state of those who experienced graft thrombosis.

RESULTS

The mean age of the patients at transplantation was 49 years. There were no demographic or immunological differences between the three groups of patients, except for the number of previous blood transfusions and panel reactive antibodies (PRA) levels. Forty-seven grafts were lost in the first year; 14 suffered venous thrombosis, and there were 10 acute rejection epidoses (ARE), 7 death-censored graft failures, 3 chronic allograft nephropathies (CAN), 6 primary nonfunctions, 5 removed due to infection, 1 primary disease relapse, and 1 hemolytic-uremic syndrome. Of the 14 cases of thrombosis in 12 patients, 10 had been on PD and 4 on HD immediately before transplant. One-year graft and patient survivals were similar: 74% HD, 68% PD, 86% preemptive, and 93% HD, 95% PD, and 96% preemptive, respectively. The hypercoagulable state showed inherited thrombophilia patterns in some cases, but most of them were normal.

CONCLUSION

Renal graft thrombosis was responsible for graft lost in PD patients within the first year, while in the HD group it was ARE and in the preemptive cohort, death with a functioning graft. The hypercoagulable state pretransplant should be more accurately studied to identify thrombotic factors other than those which are inherited.

Mortality After Heart-Lung Transplantation Experience in a Reference Center

The 2006 International Society for Heart and Lung Transplantation registry reported that there were differences in mortality after heart-lung transplantation (HLT) depending on the etiology for transplantation. Our objective was to conduct an analysis on mortality after HLT at our center.

MATERIALS AND METHODS

From January 1991 to December 2006, 25 HLT were performed on patients with the following characteristics: mean age of 38 +/- 11 years with 62% males and 4% with previous surgery. The cohort included 17% urgent transplants. The mean ischemia time was 198 +/- 60 minutes. We divided patients into four etiologic groups: congenital heart disease of the Eisenmenger type; primary pulmonary hypertension; chronic obstructive pulmonary disease/emphysema/fibrosis with right ventricular impact; or pulmonary dysfunction with concomitant left ventricular depression. Three patients were excluded from the analysis because they did not fit in any of the groups.

RESULTS

The mean follow-up of the sample was 862 +/- 1290 days. The overall hospital survival as well as that at 1 and 5 years was 59%, 50%, and 37%, respectively. In the Eisemmenger's syndrome cohort no death occurred during hospitalization and survival at 5 years was 50%.

CONCLUSIONS

HLT was a therapeutic option with high mortality. Hospital mortality was high in absolute terms. Congenital heart disease of the Eisenmenger type may be a lower risk group.

Pneumonia after lung transplantation in the RESITRA Cohort: a multicenter prospective study

The aim of the present study is to evaluate the epidemiology, etiology and prognosis of pneumonia in lung transplant (LT) recipients. This is a prospective, multicenter study of a consecutive cohort of LT recipients in Spain. From September 2003 to November 2005, 85 episodes of pneumonia in 236 LT recipients were included (incidence 72 episodes per 100 LT/year). Bacterial pneumonia (82.7%) was more frequent than fungal (14%) and viral pneumonia (10.4%). The most frequent microorganisms in each etiological group were Pseudomonas aeruginosa (n = 14, 24.6%), CMV (n = 6, 10.4%) and Aspergillus spp. (n = 5, 8.8%). Incidence of Aspergillus spp. and CMV pneumonia is lower than previously reported, probably due to the spread of universal prophylaxis. Pneumonia caused by viruses appeared significantly later than pneumonia due to gram-negative bacilli, fungi and those without known etiology (p < 0.01, p = 0.03 and p = 0.02, respectively). The routine use of ganciclovir has changed the natural history of CMV infection, so that pneumonia appears later, once prophylaxis is suspended. The probability of survival during the first year of follow-up was significantly higher in the multivariate analysis in LT recipients who did not have a pneumonia episode compared with those that had at least one episode (p < 0.01).

Effects of organosulfurs, isothiocyanates and vitamin C towards hydrogen peroxide-induced oxidative DNA damage (strand breaks and oxidized purines/pyrimidines) in human hepatoma cells

The aim of this study was to evaluate the effects of organosulfurs, isothiocyanates and vitamin C towards hydrogen peroxide-induced DNA damage (DNA strand breaks and oxidized purines/pyrimidines) in human hepatoma cells (HepG2), using the Comet assay. Treatment with hydrogen peroxide (H(2)O(2)) increased the levels of DNA strand breaks and oxidized purine and pyrimidine bases, in a concentration and time dependent manner. Organosulfur compounds (OSCs) reduced DNA strand breaks induced by H(2)O(2). In addition, OSCs also decreased the levels of oxidized pyrimidines. However, none of the OSCs tested reduced the levels of oxidized purines. Isothiocyanates compounds (ITCs) and vitamin C showed protective effects towards H(2)O(2)-induced DNA strand breaks and oxidized purine and pyrimidine bases. The results indicate that removal of oxidized purine and pyrimidine bases by ITCs was more efficient than by OSCs and vitamin C. Our findings suggest that OSCs, ITCs and vitamin C could exert their protective effects towards H(2)O(2)-induced DNA strand breaks and oxidative DNA damage by the free radical-scavenging efficiency of these compounds.

The limitations on organic detection in Mars-like soils by thermal volatilization-gas chromatography-MS and their implications for the Viking results

The failure of Viking Lander thermal volatilization (TV) (without or with thermal degradation)-gas chromatography (GC)-MS experiments to detect organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV-GC-MS may be blind to low levels of organics on Mars. A comparison between TV-GC-MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10-90 mug of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV-GC-MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO(2)) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50-700 ppm of CO(2) by TV-GC-MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV-GC-MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life.

Perioperative Complications of Lung Transplantation in Patients With Emphysema and Fibrosis: Experience From 1992–2002

Our objective was to describe the incidence of perioperative complications of lung transplantation among patients with emphysema and fibrosis and the morbidity and mortality risk factors.

MATERIALS AND METHODS

We performed a retrospective study of 111 lung transplant patients engrafted from 1992 to 2002 for emphysema (n = 65) or lung fibrosis (n = 46). This descriptive study included the most frequent complications during the perioperative period in the intensive care unit.

RESULTS

The most frequent intraoperative complications were reperfusion syndrome, hemodynamic instability, and cardiac arrhythmias. Among patients with emphysema, the follow-up of postoperative complications proved statistically significant on univariate analysis for an association of patient mortality with prolonged intubation (P = .005), rejection (P = .0001), hemorrhage (P = .0001), sepsis (P = .0001), renal failure (P = .001), and implantation response (P = .014). Mortality among these patients was 16.9%. Mechanical ventilation for over 48 hours and postoperative hemorrhage were the variables with the greatest predictive value for mortality in the postoperative period. Among patients with fibrosis, the complication-related mortality were reperfusion syndrome (P = .039), implantation response (P = .039), renal failure (P = .013), rejection (P = .016), and sepsis (P < .001). The mortality rate was 23.9% with sepsis (P = .000) being the most frequent cause of death in the immediate postoperative period.

CONCLUSIONS

The most frequent intraoperative complications were reperfusion syndrome and hemodynamic instability. The most frequent postoperative complications were implantation response, sepsis, prolonged intubation, hemorrhage, and renal failure.

Plasticity of the central nervous system (CNS) following perinatal asphyxia: does nicotinamide provide neuroprotection?

We have investigated the idea that nicotinamide, a non-selective inhibitor of the sentinel enzyme Poly(ADP-ribose) polymerase-I (PARP-1), provides neuroprotection against the long-term neurological changes induced by perinatal asphyxia. Perinatal asphyxia was induced in vivo by immersing foetuses-containing uterine horns removed from ready-to-deliver rats into a water bath for 20 min. Sibling caesarean-delivered pups were used as controls. The effect of perinatal asphyxia on neurocircuitry development was studied in vitro with organotypic cultures from substantia nigra, neostriatum and neocortex, platted on a coverslip 3 days after birth. After approximately one month in vitro (DIV 25), the cultures were treated for immunocytochemistry to characterise neuronal phenotype with markers against the N-methyl-D-aspartate receptor subunit 1 (NR1), the dopamine pacemaker enzyme tyrosine hydroxylase (TH), and nitric oxide synthase (NOS), the enzyme regulating the bioavailability of NO. Nicotinamide (0.8 mmol/kg, i.p.) or saline was administered to asphyctic and caesarean-delivered pups 24, 48 and 72 h after birth. It was found that nicotinamide treatment prevented the effect of perinatal asphyxia on several neuronal parameters, including TH- and NOS-positive neurite atrophy and NOS-positive neuronal loss; supporting the idea that nicotinamide constitutes a therapeutic alternative for the effects produced by sustained energy-failure conditions, as occurring during perinatal asphyxia.

Interpreting post-transplant proteinuria in patients with proteinuria pre-transplant

Increasing numbers of patients receive kidney transplants before initiation of dialysis or shortly thereafter. Some of these patients have significant proteinuria pre-transplant making the interpretation of post-transplant proteinuria problematic. In this study, we evaluated post-transplant proteinuria in 115 patients who had urine protein measured within 3 months of transplant and assessed the association of proteinuria with allograft pathology. Proteinuria declined rapidly from 3650 +/- 3702 mg/day pre-transplant to 550 + 918 at 3 weeks (p < 0.0001) and continued to decline until 1 year post-transplant (472 +/- 1116, p < 0.0001 vs. 3 weeks). Proteinuria greater than 3000 mg/day was present in 48 patients (42%) pre-transplant, in 1 patient (1%) at 3 weeks and in 4 patients (4%) at 1 year. Surveillance graft biopsies were done at 1 year in 93% of patients. Proteinuria > or = 1500 mg/day and/or an absolute increase in proteinuria > 500 mg/day after 3 weeks post-transplant was associated with allograft glomerular pathology. In conclusion, pre-transplant proteinuria, even when high grade, declines rapidly after transplantation. Failure to decline or persistence of proteinuria greater than 1500 mg/day is indicative of allograft pathology.

Pulmonary tuberculosis in lung and heart-lung transplantation: fifteen years of experience in a single center in Spain

The increase in the number of solid organ transplants has resulted in an increased incidence of opportunistic infections, including infection by typical and atypical mycobacteria, with risk of developing tuberculosis. Pretransplant chemoprophylaxis with isoniazid has become increasingly common in an attempt to prevent the disease. The source of infection in tuberculosis (TB) may be difficult to identify. Infection may be caused by reactivation of a primary infection in the recipient, reactivation of a lesion from the donor lung, or primary infection. There are few reports on TB in lung transplantation. Incidence in the reported series ranges from 6.5% to 10%. Our series of 7 patients out of a total 271 patients (2.58%) represents a rate higher than reported for the general Spanish population, 26.7/10(5) inhabitants and for lung transplant candidates (0.18%). Our aim was to evaluate the incidence, clinical signs, and outcome of TB in our series of patients undergoing lung transplantation in the 15 years since inception of the program (February 1990 to December 2004). Morbidity and mortality was high (42.8%), but limited to patients in whom treatment was not administered or could not be successfully completed. However, early detection and treatment are essential.

Effects of perinatal asphyxia on cell proliferation and neuronal phenotype evaluated with organotypic hippocampal cultures

The present report summarizes studies combining an in vivo and in vitro approach, where asphyxia is induced in vivo at delivery time of Wistar rats, and the long term effects on hippocampus neurocircuitry are investigated in vitro with organotypic cultures plated at postnatal day seven. The cultures preserved hippocampus layering and regional subdivisions shown in vivo, and only few dying cells were observed when assayed with a viability test at day in vitro 27. When properly fixed, cultures from asphyxia-exposed animals showed a decreased amount of microtubule-associated protein-2 immunocytochemically positive cells (approximately 30%), as compared with that from controls. The decrease in microtubule-associated protein-2 immunocytochemistry was particularly prominent in Ammon's horn 1 and dentate gyrus regions (approximately 40%). 5-Bromo-2'deoxyuridine labeling revealed a two-fold increase in cellular proliferation in cultures from asphyxia-exposed, compared with that from control animals. Furthermore, confocal microscopy and quantification using the optical disector technique demonstrated that in cultures from asphyxia-exposed animals approximately 30% of 5-bromo-2'deoxyuridine-positive cells were also positive to microtubule-associated protein-2, a marker for neuronal phenotype. That proportion was approximately 20% in cultures from control animals. Glial fibrillary acidic protein-immunocytochemistry and Fast Red nuclear staining revealed that the core of the hippocampus culture was surrounded by a well-developed network of glial fibrillary acidic protein-positive cells and glial fibrillary acidic protein-processes providing an apparent protective shield around the hippocampus. That shield was less developed in cultures from asphyxia-exposed animals. The increased mitotic activity observed in this study suggests a compensatory mechanism for the long-term impairment induced by perinatal asphyxia, although it is not clear yet if that mechanism leads to neurogenesis, astrogliogenesis, or to further apoptosis.

Lymphoproliferative Disease After Lung and Heart-Lung Transplantation: First Description in Spain

Lymphoproliferative syndromes are the most common tumors in transplant recipients. More than 90% of posttransplantation lymphoproliferative syndromes (PTLS) are considered to be associated with Epstein-Barr virus, and 86% are of the B-cell line. Histopathology ranges from polymorphic-reactive to monomorphic forms. Clonality should be studied using molecular biology techniques. Clinically, a differentiation is usually made between early PTLS (occurring within 1 year after transplantation) and late PTLS, which occur as localized or disseminated nodal lymphomas. In localized forms, immunosuppression should be discontinued or decreased, and the involved area should be subsequently resected or irradiated. In disseminated cases, immunosuppression should be decreased and administration of acyclovir/ganciclovir should be considered. If this is not effective, treatment should be started with anti-CD20 monoclonal antibodies (rituximab). If no response occurs, use of chemotherapy, possibly with interferon, should be considered. Our aim was to report the incidence, clinical signs, and treatment in a series of patients undergoing lung transplantation (LTx).

MHC-F DNA sequences in bonobo, gorilla and orangutan

The major histocompatibility complex (MHC)-F class Ib locus shows a limited polymorphism, and the function of its mainly intracellular protein is not clear. We have identified human leucocyte antigen (HLA)-F orthologous DNA sequences in Pongidae in order to study the MHC-F gene evolution and its products' function. HLA-F orthologous cDNA transcripts are found in chimpanzee and in the new primate species studied (bonobo, gorilla and orangutan). Analyses of the predicted amino acid sequences and their comparison with other primate MHC-F proteins show that MHC-F may be a protein with a typical class I structure and that the key residues of the peptide-binding region (PBR) are highly conserved in MHC-F in all studied primates species. Thus, MHC-F conservation along the primate evolution suggests an important role in cellular physiology. It is possible that the MHC-F protein could be involved, together with MHC-G and MHC-E, in the natural killer (NK) cell activity regulation, although rhesus macaque does not express MHC-G and MHC-E orthologues. The evolutionary pathway of the six-base-pair deletion at exon 2 existing in some primates is put forward.

Aspergillus infections in lung transplant recipients: risk factors and outcome

This retrospective study of 251 lung transplant patients aimed to determine the prevalence, clinical presentation and mortality of Aspergillus infection in order to define specific risk factors and to compare survival in patients with and without infection. Aspergillus was isolated from 86 (33%) cases, which involved colonisation (n = 50), tracheobronchial lesions (n = 17) or invasive aspergillosis (n = 19). Overall, aspergillosis had an impact on survival (p < 0.05); in fact the 5-year mortality rate was substantially higher in single lung transplant recipients with bronchial anastomotic infection, and in those with late-onset infections and chronic rejection. A significant association (p < 0.05) was found between acute rejection and the time at which fungal infection was diagnosed. Aspergillus infection was not related to cytomegalovirus infection or treatment with corticosteroids. The mortality rate for invasive infections was 78% and was related to survival (p < 0.0001); invasive aspergillosis was also associated with chronic rejection (p < 0.05), but not with high corticosteroid doses (p 0.49) or use of tacrolimus (p 0.73). In conclusion, Aspergillus infection was associated with a reduction in the 5-year survival rate of lung transplant recipients, and this was particularly true for patients infected with the invasive forms and for patients with single lung transplants, bronchial anastomotic infection and chronic rejection. Isolation of Aspergillus spp. from respiratory samples preceded acute rejection, and may be a marker of graft dysfunction and/or airway inflammation. Close monitoring, or even pre-emptive antifungal therapy, is recommended for patients with chronic rejection or bronchial airway mechanical abnormalities and persistent Aspergillus colonisation.