TRAF2 is essential for JNK but not NF-kappaB activation and regulates lymphocyte proliferation and survival

TRAF2 is believed to mediate the activation of NF-kappaB and JNK induced by the tumor necrosis factor receptor (TNFR) superfamily, which elicits pleiotropic responses in lymphocytes. We have investigated the physiological roles of TRAF2 in these processes by expressing a lymphocyte-specific dominant negative form of TRAF2, thereby blocking this protein's effector function. We find that the TNFR superfamily signals require TRAF2 for activation of JNK but not NF-kappaB. In addition, we show that TRAF2 induces NF-kappaB-independent antiapoptotic pathways during TNF-induced apoptosis. Inhibition of TRAF2 leads to splenomegaly, lymphadenopathy, and an increased number of B cells. These findings indicate that TRAF2 is involved in the regulation of lymphocyte function and growth in vivo.

CD28-independent, TRAF2-dependent costimulation of resting T cells by 4-1BB ligand

4-1BB ligand (4-1BBL) is a member of the tumor necrosis factor (TNF) family expressed on activated antigen-presenting cells. Its receptor, 4-1BB, is a member of the TNF receptor family expressed on activated CD4 and CD8 T cells. We have produced a soluble form of 4-1BBL using the baculovirus expression system. When coimmobilized on plastic with anti-CD3, soluble 4-1BBL induces interleukin (IL)-2 production by resting CD28+ or CD28- T cells, indicating that 4-1BBL can function independently of other cell surface molecules, including CD28, in costimulation of resting T cell activation. At low concentrations of anti-CD3, 4-1BBL is inferior to anti-CD28 in T cell activation. However, when 4-1BB ligand is provided together with strong TCR signals, then 4-1BBL and anti-CD28 are equally potent in stimulation of IL-2 production by resting T cells. We find that TNF receptor-associated factor (TRAF)1 or TRAF2 associate with a glutathione S-transferase-4-1BB cytoplasmic domain fusion protein in vitro. In T cells, we find that association of TRAF1 and TRAF2 with 4-1BB requires 4-1BB cross-linking. In support of a functional role for TRAF2 in 4-1BB signaling, we find that resting T cells isolated from TRAF2-deficient mice or from mice expressing a dominant negative form of TRAF2 fail to augment IL-2 production in response to soluble 4-1BBL. Thus 4-1BB, via the TRAF2 molecule, can provide CD28-independent costimulatory signals to resting T cells.

Increased expression of transforming growth factor beta isoforms (beta 1, beta 2, beta 3) in bleomycin-induced pulmonary fibrosis

Evidence suggests that transforming growth factor beta (TGF-beta) may play a central role in a variety of fibroproliferative disorders via the induction of extracellular matrix accumulation. The three mammalian TGF-beta isoforms are present in the normal lung, but very little is known about their expression during lung injury and repair. To more fully understand the role of TGF-beta in lung repair, we investigated the expression of the TGF-beta 1, TGF-beta 2, and TGF-beta 3 isoforms in a bleomycin-induced model of pulmonary fibrosis using immunohistochemical and in situ hybridization techniques. We found expression of the three TGF-beta isoforms, in an identical pattern, widely distributed throughout the normal rat lung: in airways, blood vessels, lung parenchyma, and alveolar macrophages. In general, the distribution of TGF-beta mRNA and protein coincided; however, bronchial epithelial cells were a notable exception, exhibiting immunoreactivity but no mRNA expression. During the "inflammatory" phase (days 1 and 3) of bleomycin-induced injury there was an increase in the mRNA and protein expression of all three TGF-beta isoforms in the injured areas, most prominently in parenchymal cells and alveolar macrophages. There was a further increase in TGF-beta isoform expression in the areas of developing fibrosis during the later reparative phase (days 7 and 14), and the bronchial epithelium, previously not expressing TGF-beta mRNA, showed strong expression of mRNA for the three isoforms concomitant with increased immunoreactivity. These findings implicate the three mammalian TGF-beta isoforms in the dysregulated repair process that results in pulmonary fibrosis. Furthermore, the pattern of TGF-beta mRNA and protein expression by the bronchial epithelium suggests that a transition may occur at this site from a paracrine mode of action in the normal lung to an autocrine mode of action during the "reparative" phase of fibrosis.

A regulatory role for TRAF1 in antigen-induced apoptosis of T cells

Tumor necrosis factor receptor (TNFR)-associated factor 2 (TRAF2) and TRAF1 were found as components of the TNFR2 signaling complex, which exerts multiple biological effects on cells such as cell proliferation, cytokine production, and cell death. In the TNFR2-mediated signaling pathways, TRAF2 works as a mediator for activation signals such as NF-kappaB, but the role of TRAF1 has not been previously determined. Here we show in transgenic mice that TRAF1 overexpression inhibits antigen-induced apoptosis of CD8(+) T lymphocytes. Our results demonstrate a biological role for TRAF1 as a regulator of apoptotic signals and also support the hypothesis that the combination of TRAF proteins in a given cell type determines distinct biological effects triggered by members of the TNF receptor superfamily.

Primary hyperoxaluria type 1 in the Canary Islands: a conformational disease due to I244T mutation in the P11L-containing alanine:glyoxylate aminotransferase

Primary hyperoxaluria type 1 (PH1) is an inborn error of metabolism resulting from a deficiency of alanine:glyoxylate aminotransferase (AGXT; EC 2.6.1.44). Most of the PH1 alleles detected in the Canary Islands carry the Ile-244 --> Thr (I244T) mutation in the AGXT gene, with 14 of 16 patients homozygous for this mutation. Four polymorphisms within AGXT and regional microsatellites also were shared in their haplotypes (AGXT*LTM), consistent with a founder effect. The consequences of these amino acid changes were investigated. Although I244T alone did not affect AGXT activity or subcellular localization, when present in the same protein molecule as Leu-11 --> Pro (L11P), it resulted in loss of enzymatic activity in soluble cell extracts. Like its normal counterpart, the AGXT*LTM protein was present in the peroxisomes but it was insoluble in detergent-free buffers. The polymorphism L11P behaved as an intragenic modifier of the I244T mutation, with the resulting protein undergoing stable interaction with molecular chaperones and aggregation. This aggregation was temperature-sensitive. AGXT*LTM expressed in Escherichia coli, as a GST-fusion protein, and in insect cells could be purified and retained enzymatic activity. Among various chemical chaperones tested in cell culture, betaine substantially improved the solubility of the mutant protein and the enzymatic activity in cell lysates. In summary, I244T, the second most common mutation responsible for PH1, is a protein conformational disease that may benefit from new therapies with pharmacological chaperones or small molecules to minimize protein aggregation.

Microplastic and tar pollution on three Canary Islands beaches: An annual study

Marine debris accumulation was analyzed from three exposed beaches of the Canary Islands (Lambra, Famara and Las Canteras). Large microplastics (1-5mm), mesoplastics (5-25mm) and tar pollution were assessed twice a month for a year. There was great spatial and temporal variability in the Canary Island coastal pollution. Seasonal patterns differed at each location, marine debris concentration depended mainly of local-scale wind and wave conditions. The most polluted beach was Lambra, a remote beach infrequently visited. The types of debris found were mainly preproduction resin pellets, plastic fragments and tar, evidencing that pollution was not of local origin, but it cames from the open sea. The levels of pollution were similar to those of highly industrialized and contaminated regions. This study corroborates that the Canary Islands are an area of accumulation of microplastics and tar rafted from the North Atlantic Ocean by the southward flowing Canary Current.

Metalloproteinases and tissue inhibitor of metalloproteinases in mesothelial cells. Cellular differentiation influences expression

Mesothelial cells play a critical role in the remodeling process that follows serosal injury. Although mesothelial cells are known to synthesize a variety of extracellular matrix components including types I, III, and IV collagens, their potential to participate in matrix degradation has not been explored. We now report that human pleural and peritoneal mesothelial cells express interstitial collagenase, 72- and 92-kD gelatinases (type IV collagenases), and the counterregulatory tissue inhibitor of metalloproteinases (TIMP). Our initial characterization of the mesothelial cell metalloenzymes and TIMP has revealed: (a) they are likely identical to corresponding molecules secreted by other human cells; (b) they are secreted rather than stored in an intracellular pool; (c) a primary site of regulation occurs at a pretranslational level; (d) phorbol myristate acetate, via activation of protein kinase C, upregulates expression of collagenase, 92-kD gelatinase, and TIMP, but has no effect on expression of 72-kD gelatinase; and (e) lipopolysaccharide fails to upregulate the biosynthesis of either metalloproteinases or TIMP. Of particular interest is the observation that the state of cellular differentiation has a striking influence on the expression of metalloenzymes and TIMP, such that epitheloid cells display a more matrix-degradative phenotype (increased 92-kD gelatinase and decreased TIMP) than their fibroblastoid counterparts. We speculate that mesothelial cells directly participate in the extracellular matrix turnover that follows serosal injury via elaboration of metalloproteinases and TIMP. Additionally, the reactive cuboidal mesothelium which is characteristic of the early response to serosal injury may manifest a matrix-degenerative phenotype favoring normal repair rather than fibrosis.

CD43, a molecule with multiple functions

To initiate a specific immune response, lymphoid cells integrate a variety of signals generated through the orchestrated interaction of multiple cell surface molecules with their counter-receptors. As a result of the specific recognition of the antigen through antigen-specific receptors, and of the monitoring of their particular environment through the so-called coreceptor molecules, lymphoid cells go through elaborate processes of maturation and activation, contributing to the plasticity and sensitivity of immune response. CD43 is the major sialic acid rich protein on the surface of lymphocytes. However, the specific roles of this protein in different lymphoid cells under normal physiological conditions remain largely unknown. In this review we will mainly focus on the recent advances concerning the functions of this molecule as a coreceptor of different lymphoid cells as well as on the participation of this molecule in different pathologies.

Mild hypothermia mitigates post-ischemic neuronal death following focal cerebral ischemia in rat brain: immunohistochemical study of Fas, caspase-3 and TUNEL

Mild hypothermia is considered to have a protective effect during ischemic neuronal cell death. The present study provides experimental evidence for this beneficial role of mild hypothermia using reversible middle cerebral artery occlusion (MCAo) in a Sprague-Dawley (SD) rat model. MCAo was induced in rats for 1 h followed by reperfusion at different periods. Hematoxylin-eosin (HE) staining in normothermic (NT) 37 degrees C and hypothermic (HT) 33 degrees C groups of rats confirmed cerebral infarcts. The mean per cent infarct area was significantly reduced in the HT group of rats. Immunohistochemical analysis was done using anti-Fas and caspase-3 antibodies. The immunohistochemical expression of Fas and caspase-3 was demonstrable as early as 5 h after reperfusion, but the expression pattern maximized at 24 h after reperfusion. The expression of Fas and caspase-3 proteins showed a clear decrease in the HT group over the NT group. In situ detection of DNA fragmentation was done using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling method (TUNEL). TUNEL-positive cells were first observed at 5h after reperfusion and progressively increased by 24h. A higher number of TUNEL-positive cells was found in the NT group, but they were significantly decreased in the HT group. Further, DNA fragmentation was confirmed by size fractionation in agarose gel. These findings demonstrate a positive relation between the expression of Fas, caspase-3 and TUNEL-positive cells.

Stimulus-dependent synergism of the antiapoptotic tumor necrosis factor receptor-associated factor 2 (TRAF2) and nuclear factor kappaB pathways

Tumor necrosis factor (TNF) signaling leads to pleiotropic responses in a wide range of cell types, in part by activating antiapoptotic and proapoptotic signaling pathways. Thus, although TNF can cause apoptosis and may prove useful in the treatment of malignancies, most cells are resistant to TNF-induced cell death unless de novo protein synthesis is inhibited. Previous studies suggested that TNF activation of the nuclear factor (NF)-kappaB transcription factor family antagonizes the proapoptotic signals initiated by TNF-alpha. TNF receptor-associated factor (TRAF)2 has also been shown to mediate crucial antiapoptotic signals during TNF stimulation, yet is not essential in activation of NF-kappaB under physiologic conditions, thus raising questions about the relationship between these antiapoptotic pathways. We report here that inhibition of TRAF2 and NF-kappaB function in primary cells, by coexpression of a constitutive repressor of multiple NF-kappaB/Rel proteins (IkappaBalpha.DN) and a dominant negative form of TRAF2 (TRAF2.DN), synergistically enhanced TNF-induced apoptosis. The effects were stimulus dependent, such that neither inhibitory molecule affected Fas- and daunorubicin-induced apoptosis to the same degree as TNF-induced death. These findings indicate that the NF-kappaB and TRAF2 pathways activate independent antiapoptotic mechanisms which act in concert to suppress the proapoptotic signals induced by TNF-alpha.

Strength training combined with plyometric jumps in adults: sex differences in fat-bone axis adaptations

Leptin and osteocalcin play a role in the regulation of the fat-bone axis and may be altered by exercise. To determine whether osteocalcin reduces fat mass in humans fed ad libitum and if there is a sex dimorphism in the serum osteocalcin and leptin responses to strength training, we studied 43 male (age 23.9 2.4 yr, mean +/- SD) and 23 female physical education students (age 23.2 +/- 2.7 yr). Subjects were randomly assigned to two groups: training (TG) and control (CG). TG followed a strength combined with plyometric jumps training program during 9 wk, whereas the CG did not train. Physical fitness, body composition (dual-energy X-ray absorptiometry), and serum concentrations of hormones were determined pre- and posttraining. In the whole group of subjects (pretraining), the serum concentration of osteocalcin was positively correlated (r = 0.29-0.42, P < 0.05) with whole body and regional bone mineral content, lean mass, dynamic strength, and serum-free testosterone concentration (r = 0.32). However, osteocalcin was negatively correlated with leptin concentration (r = -0.37), fat mass (r = -0.31), and the percent body fat (r = -0.44). Both sexes experienced similar relative improvements in performance, lean mass (+4-5%), and whole body (+0.78%) and lumbar spine bone mineral content (+1.2-2%) with training. Serum osteocalcin concentration was increased after training by 45 and 27% in men and women, respectively (P < 0.05). Fat mass was not altered by training. Vastus lateralis type II MHC composition at the start of the training program predicted 25% of the osteocalcin increase after training. Serum leptin concentration was reduced with training in women. In summary, while the relative effects of strength training plus plyometric jumps in performance, muscle hypertrophy, and osteogenesis are similar in men and women, serum leptin concentration is reduced only in women. The osteocalcin response to strength training is, in part, modulated by the muscle phenotype (MHC isoform composition). Despite the increase in osteocalcin, fat mass was not reduced.

Leptin receptor 170 kDa (OB-R170) protein expression is reduced in obese human skeletal muscle: a potential mechanism of leptin resistance

To examine whether obesity-associated leptin resistance could be due to down-regulation of leptin receptors (OB-Rs) and/or up-regulation of suppressor of cytokine signalling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle, which blunt janus kinase 2-dependent leptin signalling and signal transducer and activator of transcription 3 (STAT3) phosphorylation and reduce AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) phosphorylation. Deltoid and vastus lateralis muscle biopsies were obtained from 20 men: 10 non-obese control subjects (mean +/- s.d. age, 31 +/- 5 years; height, 184 +/- 9 cm; weight, 91 +/- 13 kg; and percentage body fat, 24.8 +/- 5.8%) and 10 obese (age, 30 +/- 7 years; height, 184 +/- 8 cm; weight, 115 +/- 8 kg; and percentage body fat, 34.9 +/- 5.1%). Skeletal muscle OB-R170 (OB-R long isoform) protein expression was 28 and 25% lower (both P < 0.05) in arm and leg muscles, respectively, of obese men compared with control subjects. In normal-weight subjects, SOCS3 protein expression, and STAT3, AMPKalpha and ACCbeta phosphorylation, were similar in the deltoid and vastus lateralis muscles. In obese subjects, the deltoid muscle had a greater amount of leptin receptors than the vastus lateralis, whilst SOCS3 protein expression was increased and basal STAT3, AMPKalpha and ACCbeta phosphorylation levels were reduced in the vastus lateralis compared with the deltoid muscle (all P < 0.05). In summary, skeletal muscle leptin receptors and leptin signalling are reduced in obesity, particularly in the leg muscles.

Influence of dialysis duration and modality on kidney transplant outcomes

BACKGROUND

The influence of pretransplantation dialysis on kidney transplant outcomes has been the subject of longstanding interest. Although increased time on dialysis prior to kidney transplantation is associated with decreased graft and patient survivals, analyses of the impact of dialysis modality on kidney allograft outcome have produced conflicting results.

OBJECTIVE

The objective of this study was to evaluate the influence of dialysis duration and modality on the function and survival of renal allografts.

PATIENTS

We retrospectively reviewed the clinical data of 421 adults who received first kidney transplantations from cadaveric heart-beating donors performed in our unit from May 1989 to May 2007. Three hundred seventy-four patients (88.8%) were on hemodialysis (HD) prior to kidney transplantation, including 247 patients (58.7%) on treatment for at least 24 months.

RESULTS

Patients with a dialysis duration > or =24 months were significantly older (45.9 vs 42.8 years; P = .013). Renal function at 3, 12, 60, and 96 months was similar between the 2 groups. Longer duration on dialysis was associated with poorer overall graft and patient survivals. No differences were observed in renal function or graft and patient survivals comparing HD or peritoneal dialysis (PD). Multivariate analysis confirmed the lack of correlation between dialysis duration or modality and allograft failure.

CONCLUSION

Longer dialysis duration influenced overall graft and patient survival. However, dialysis modality showed no influence on graft function or survival.

Acid secretory capacity and plasma gastrin concentration after administration of omeprazole to normal subjects

In a randomized double-blind study, two groups of eight healthy volunteers received either placebo or omeprazole 40 mg o.m. for 14 days. Fasting plasma gastrin concentration and peak acid output in response to a maximal intravenous dose of pentagastrin were measured before, during and after the 14 days of treatment. Omeprazole caused a 68% (mean) decrease in the peak acid output when measured 24 hours after the last dose, with a simultaneous increase in the fasting plasma gastrin concentration. When measured 1, 2, 3 and 8 weeks after cessation of treatment, there was no significant difference in the peak acid output between the two groups. The study demonstrates that there is no increase in the acid production capacity after 2 weeks of treatment with omeprazole. Thus it would appear that the rise in the plasma gastrin concentration during short-term treatment with omeprazole does not induce parietal cell hypertrophy or hyperplasia.

Insulin - producing cells derived from stem cells: recent progress and future directions

Type 1 diabetes is characterized by the selective destruction of pancreatic beta-cells caused by an autoimmune attack. Type 2 diabetes is a more complex pathology which, in addition to beta-cell loss caused by apoptotic programs, includes beta-cell dedifferentiation and peripheric insulin resistance. beta-Cells are responsible for insulin production, storage and secretion in accordance to the demanding concentrations of glucose and fatty acids. The absence of insulin results in death and therefore diabetic patients require daily injections of the hormone for survival. However, they cannot avoid the appearance of secondary complications affecting the peripheral nerves as well as the eyes, kidneys and cardiovascular system. These afflictions are caused by the fact that external insulin injection does not mimic the tight control that pancreatic-derived insulin secretion exerts on the body's glycemia. Restoration of damaged beta-cells by transplantation from exogenous sources or by endocrine pancreas regeneration would be ideal therapeutic options. In this context, stem cells of both embryonic and adult origin (including beta-cell/islet progenitors) offer some interesting alternatives, taking into account the recent data indicating that these cells could be the building blocks from which insulin secreting cells could be generated in vitro under appropriate culture conditions. Although in many cases insulin-producing cells derived from stem cells have been shown to reverse experimentally induced diabetes in animal models, several concerns need to be solved before finding a definite medical application. These refer mainly to the obtainment of a cell population as similar as possible to pancreatic beta-cells, and to the problems related with the immune compatibility and tumor formation. This review will summarize the different approaches that have been used to obtain insulin-producing cells from embryonic and adult stem cells, and the main problems that hamper the clinical applications of this technology.

Total body zinc depletion and its relationship to the development of hyperprolactinemia in chronic renal insufficiency

Modulation of free plasma zinc levels has been implicated in the increase in plasma prolactin levels seen in patients with chronic renal insufficiency (CRI). The relative importance of this mechanism in comparison to others, however, has not been elucidated. Zinc equilibrium between plasma and red blood cells is partly dependent upon red blood cell carbonic anhydrase (CA). In the present paper, we have investigated the interrelationships among total plasma zinc, leukocyte zinc, prolactin, and erythrocyte CA in patients with CRI. Uremic patients were shown to have significantly increased levels of plasma prolactin and erythrocyte CA activity when compared to normal controls. Moreover, red blood cell CA total concentration and isoenzyme-I and-II levels, as well as plasma zinc were found to be significantly decreased in uremic patients in comparison to normal controls. In patients with CRI, a negative correlation was demonstrated between erythrocyte CA catalytic activity and plasma zinc, as well as between plasma zinc and plasma prolactin levels. Moreover, leukocyte zinc content, which is a reliable indicator of total body zinc stores, was found to be significantly decreased in uremic patients when compared to normal controls. A strong negative correlation between leukocyte zinc content and plasma prolactin levels was documented in CRI patients. Our results suggest that alterations in erythrocyte CA levels, enzymatic activity or isoenzyme profile are most probably mechanistically and etiologically unrelated to the high plasma prolactin levels in CRI patients. Contrariwise, depletion of total body zinc stores, rather than redistribution of this trace metal among extracellular compartments, may represent one of the major contributing mechanisms leading to uremic hyperprolactinemia.

Inflammatory responses induced by poly-L-arginine in rat lungs in vivo

The inflammatory responses induced by the synthetic polycation poly-L-arginine injected either into the pleural cavity or into the trachea in rats have been investigated. Poly-L-arginine (4-40 nmol/rat) injected intrapleurally induced exudate formation and leucocyte migration (mainly polymorphonuclear cells). The exudate formation (but not cell migration) was dependent on the molecular weight of the poly-L-arginine used (24 and 115 kD). The poly-L-arginine-induced pleurisy was mainly dependent on activation of mast cells since it was significantly reduced either in rats depleted of their stores of histamine and serotonin or in rats previously treated with the serotonin receptor antagonist methysergide. The polyanions heparin and dermatan sulphate when administered intrapleurally with the polycation markedly reduced the exudate formation. Poly-L-arginine (115 kD, 8.5 nmol/rat) injected intratracheally caused lung oedema, increased leucocyte number and protein content of bronchoalveolar lavage, respiratory insufficiency and 60% mortality in 6 h. Depletion of histamine and serotonin stores or of circulating neutrophils decreased the leucocytes in bronchoalveolar lavage but did not increase survival rate, whereas the polyanion dermatan sulphate prevented the mortality completely. These results suggest that the inflammatory changes caused by poly-L-arginine are dependent on mast cell activation but that the lethality after intratracheal administration is due to electrostatic interactions of the polycation with anionic surfaces present in the pulmonary epithelium.

Single cell-derived clones from human adipose stem cells present different immunomodulatory properties

Human adipose mesenchymal stem cells are a heterogeneous population, where cell cultures derived from single-cell-expanded clones present varying degrees of differential plasticity. This work focuses on the immunomodulatory/anti-inflammatory properties of these cells. To this end, five single-cell clones were isolated (generally called 1.X and 3.X) from two volunteers. Regarding the expression level of the lineage-characteristic surface antigens, clones 1·10 and 1·22 expressed the lowest amounts, while clones 3·10 and 3·5 expressed more CD105 than the rest and clone 1·7 expressed higher amounts of CD73 and CD44. Regarding cytokine secretion, all clones were capable of spontaneously releasing high levels of interleukin (IL)-6 and low to moderate levels of IL-8. These differences can be explained in part by the distinct methylation profile exhibited by the clones. Furthermore, and after lipopolysaccharide stimulation, clone 3.X produced the highest amounts of proinflammatory cytokines such as IL-1β, while clones 1·10 and 1·22 highly expressed IL-4 and IL-5. In co-culture experiments, clones 1.X are, together, more potent inhibitors than clones 3.X for proliferation of total, CD3(+) T, CD4(+) T and CD8(+) T lymphocytes and natural killer (NK) cells. The results of this work indicate that the adipose stem cell population is heterogeneous in cytokine production profile, and that isolation, characterization and selection of the appropriate cell clone is a more exact method for the possible treatment of different patients or pathologies.

Trypanosoma brucei brucei: regulation of ornithine decarboxylase in procyclic forms and trypomastigotes

Ornithine decarboxylase (ODC) activity was measured in procyclic forms of Trypanosoma brucei brucei grown in semidefined medium. ODC activity rapidly increased in late log-phase cells which were resuspended in fresh medium. A biphasic induction curve similar to that observed in mammalian cells was observed over an 18-hr period. ODC activity increased 4.5- to 25-fold over control levels measured at zero time. Actinomycin D and cycloheximide inhibited induction by greater than 90%. Polyamines at a level not inhibitory to growth (10 microM) inhibited ODC induction, but only by 30-50%, late in the induction period. Putrescine inhibited the first peak of induction and suppressed activity at 14 hr by 75%. Polyamine analogs such as bis(ethyl)spermidine were not effective suppressors of ODC activity. The half-life of ODC in procyclic forms grown in the presence of cycloheximide was greater than 6 hr, while that of bloodstream trypomastigotes in mice treated with cycloheximide was 5 hr. A single dose of the ODC inhibitor DL-alpha-difluoromethylornithine given to infected rats or mice suppressed trypanosome ODC activity greater than 90% for more than 7 hr. These studies indicate that although trypanosome ODC increases rapidly under log growth conditions, it is less susceptible to fluctuation and external control than the enzyme from mammalian sources. The latter may be a factor in the clinical efficacy of ODC inhibitors.

Late onset of subcutaneous emphysema and hypercarbia following laparoscopic cholecystectomy

Laparoscopic surgical techniques are increasingly being applied to treat intraperitoneal abnormalities. These minimally invasive techniques potentially offer decreased operation time, decreased morbidity, and decreased length of hospitalization stays. These procedures, however are not without potential morbidity. Herein we describe two patients treated with laparoseopic cholecystectomy whose cases were complicated with subcutaneous emphysema and hyperearbia without pneumothorax. In each of these cases, carbon dioxide gas was used to induce pneumoperitoneum. In one of the cases, the hypercarbia was a late event occurring during the surgery, and in the second case, the first such description in the literature (to our knowledge), hypercarbia developed after termination of the induced pneumoperitoneum.

Impact of donor age on renal allograft function and survival

BACKGROUND

The lack of cadaveric donors coupled with a rapidly growing number of potential recipients have stimulated the implementation of several strategies, including the acceptance of older donors, to increase the organ pool and reduce the waiting list for kidney transplantation. However several studies have demonstrated higher incidences of delayed graft function and poor graft outcomes among kidneys harvested from older donors.

OBJECTIVE

The objective of this study was to evaluate the influence of donor age on the function and long-term survival of renal allografts.

PATIENTS

We performed a retrospective review of the clinical data from 441 adult kidney transplantation from cadaveric heart-beating donors performed in our unit from May 1989 to May 2007.

RESULTS

Recipients of kidney allografts from older donors were significantly older (49.2 vs 43.7 years; P < .0001) and had a higher incidence of delayed graft function (15.1% vs 5.4%; P = .005). Renal function was superior following kidney transplantation using younger donors not only at 3 months (P < .0001) and 12 months (P < .0001) posttransplantation, but also upon long-term follow-up at 60 months (P < .0001) and 96 months (P = .030). Allograft survival censored for death with a functioning graft and patient survival were not different when comparing older versus younger donors. Multivariate analysis confirmed the lack of correlation between donor age and allograft failure.

CONCLUSION

Donor age showed no influence on allograft survival. However, kidney allografts from older donors displayed lower first year and long-term renal function.

Mycophenolate mofetil: ten years' experience of a renal transplant unit

Mycophenolate mofetil (MMF) use in renal transplantation has allowed a significant decrease in early acute rejection rates. We retrospectively evaluated the incidence of acute rejection episodes, renal function at the first year posttransplant, patient and graft survivals, cytomegalovirus (CMV) infection rate, influence of the degree of sensitization, and number of MHC antigen mismatches on graft survival in two groups of patients receiving either MMF or azathioprine. Group 1 included 149 patients receiving cyclosporine, MMF, and prednisolone; group 2 included 191 patients receiving cyclosporine, azathioprine, and prednisolone. The two groups did not differ in terms of age, sex, degree of sensitization (expressed as percentage of antibodies reactive to panel), MHC mismatch number, cold ischemia time, donor age, or anti-thymocyte globulin induction. In group 1 (MMF) there was a significant decrease in early acute rejection rate (19% vs 57%, P < .0001), longer graft survival at 10 years (92% vs 75%, P = .006), and higher rate of CMV infection (22% vs 12%, P = .004). Renal function at the first year posttransplant and patient survival during follow-up did not differ between the groups. The degree of sensitization influenced graft survival in group 2. The number of MHC mismatches did not influence graft survival in either group. With MMF, there was a significant reduction in early acute rejection rate, a significant increase in graft survival at 10-year follow-up, and diminished impact of the degree of sensitization on graft survival.

GATA-1 mutation alters the spermatogonial phase and steroidogenesis in adult mouse testis

GATA-1 is a transcription factor from the GATA family, which features zinc fingers for DNA binding. This protein was initially identified as a crucial regulator of blood cell differentiation, but it is currently known that the Gata-1 gene expression is not limited to this system. Although the testis is also a site of significant GATA-1 expression, its role in testicular cells remains considerably unexplored. In the present study, we evaluated the testicular morphophysiology of adult ΔdblGATA mice with a mutation in the GATA-1 protein. Regarding testicular histology, GATA-1 mutant mice exhibited few changes in the seminiferous tubules, particularly in germ cells. A high proportion of differentiated spermatogonia, an increased number of apoptotic pre-leptotene spermatocytes (Caspase-3-positive), and a high frequency of sperm head defects were observed in ΔdblGATA mice. The main differences were observed in the intertubular compartment, as ΔdblGATA mice showed several morphofunctional changes in Leydig cells. Reduced volume, increased number and down-regulation of steroidogenic enzymes were observed in ΔdblGATA Leydig cells. Moreover, the mutant animal showed lower serum testosterone concentration and high LH levels. These results are consistent with the phenotypic and biometric data of mutant mice, i.e., shorter anogenital index and reduced accessory sexual gland weight. In conclusion, our findings suggest that GATA-1 protein is an important factor for germ cell differentiation as well as for the steroidogenic activity in the testis.