E2F4 plays a key role in Burkitt lymphoma tumorigenesis

Sporadic Burkitt lymphoma (sBL) is a rapidly growing B-cell non-Hodgkin's lymphoma whose treatment requires highly aggressive therapies that often result severely toxic. Identification of proteins whose expression or function is deregulated in sBL and play a role in its formation could facilitate development of less toxic therapies. We have previously shown that E2F1 expression is deregulated in sBL. We have now investigated the mechanisms underlying E2F1 deregulation and found that the E2F sites in its promoter fail to repress its transcriptional activity in BL cells and that the transcriptional repressor E2F4 barely interacts with these sites. We also have found that E2F4 protein levels, but not those of its mRNA, are reduced in sBL cell lines relative to immortal B-cell lines. E2F4 protein expression is also decreased in 24 of 26 sBL tumor samples from patients compared with control tissues. Our data demonstrate that enforced E2F4 expression in BL cells not only diminishes E2F1 levels, but also reduces selectively the tumorigenic properties and proliferation of BL cells, while increasing their accumulation in G(2)/M. Our results therefore point to E2F4 as a target for developing novel and less toxic treatments for sBL.

Arterial and cardiopulmonary baroreflex control of renal nerve activity in cirrhosis

Cirrhotic rats (common bile duct ligation; CBDL) have increased efferent renal sympathetic nerve activity (ERSNA), which contributes significantly to the observed renal sodium and water retention and edema formation. Basal ERSNA is increased and fails to suppress normally during intravenous isotonic saline volume expansion. Arterial and cardiopulmonary baroreflex control of ERSNA in CBDL and control (CTR) rats was examined. CBDL rats exhibited hyperdynamic circulation with increased cardiac index and decreased total peripheral resistance index and arterial pressure compared with CTR rats. Increases in left ventricular end-diastolic pressure (LVEDP) produced by volume expansion increased cardiac index normally in CBDL rats. The maximal gain of aortic baroreflex control of ERSNA was similar in CBDL and CTR rats. In CBDL rats, during decreased arterial pressure, there was a decreased range of the central component, which accounted for the decreased range of the overall aortic baroreflex, with the range of the afferent component being normal. For cardiopulmonary baroreflex control of ERSNA, the LVEDP threshold was increased and the gain was decreased in CBDL compared with CTR rats; this was due to an increased LVEDP threshold and a diminished gain of the afferent component while the central portion of the reflex was normal. These abnormalities in the cardiopulmonary baroreflex account for the attenuated decrease in ERSNA in CBDL compared with CTR rats during volume expansion. In CBDL rats, attenuation of cardiopulmonary baroreflex control of ERSNA contributes to both the increased basal ERSNA and its failure to normally suppress during volume expansion.

Analysis of Survival After Liver Transplantation in Galicia, Spain

BACKGROUND

Transplantation is the treatment of choice for many patients with end-stage liver disease. We evaluated the results of liver transplantation in Galicia, an autonomous community in Northwest Spain.

METHODS

We analyzed 452 patients and 490 grafts from 1996 to 2000 for causes of loss with respect to recipient and donor variables using the actuarial method, Kaplan-Meier curves, log-rank test, and Cox proportional risks model.

RESULTS

The overall graft survival was 77% and 64% at 1 and 5 years, respectively; while that of the patients was 83% and 69%. The risk factors for graft loss were donation in heart failure (HR = 4.91, CI:2.51-9.61); donor age (HR = 1.70, CI:1.01-2.85 between 40 and 60 years; HR = 2.37, CI:1.37-4.10 in those over 60 years, as compared to patients under 40); urgent transplant (HR = 3.95, CI:2.07-7.54); and transplant due to acute liver failure (HR = 3.53, CI:1.72-7.25) as compared to alcoholic cirrhosis. For patient death the risk factors were age of recipient over 60 years, compared to those under 40 (HR = 2.42, CI:1.11-5.28); foreign place of origin (HR = 2.02, CI:1.14-3.59); transplant due to viral cirrhosis (HR = 1.76, CI:1.03-3.02) and transplant due to acute liver failure (HR = 4.62, CI:2.12-10.06), as compared to alcoholic cirrhosis; urgent transplant (HR = 2.65, CI:1.48-4.72), and age of donor over 60 years, as compared to those under 40 (HR = 2.65, CI:1.48-4.72). Infections were the principal cause of death (45%), mostly in the first month (72%); while after the first year, 74% were due to recurrence of the primary disease and de novo malignancy.

CONCLUSIONS

Graft and patient survivals were comparable to international registries. The donor characteristics had a greater influence on graft survival than on patient survival.

Organ Donation Process: Quinquennial Analysis in a Spanish Autonomous Region

BACKGROUND

At present, transplantation of organs represents a therapeutic alternative, but the candidates for this treatment suffer from the scarcity of donors. We analyzed the process of the donation of organs in Galicia, an autonomous region in the northwest of Spain.

METHODS

We summed all the potential donors in Galicia between January 1996 and December 2000 to analyze the reasons for nonconversion, the characteristics of the actual donors, and the use of the generated organs.

RESULTS

We found 779 potential donors of whom 443 (56%) became actual donors (annual rate 31.6 pmp), although an important interterritorial variability was observed. The main reason for not obtaining potential donors was family refusal (32%), with denial during life being given as the reason in 45% of these families. We observed a progressive aging of the donors (39% older than 60 years in 2000), who had a mean age of 46 +/- 18 years. There also was an increased percentage of deaths due to vascular causes (mean 53%), while traumatic deaths (mean 40%) showed an inverse tendency. Donation because of asystole represented 5%. Among all the retrievals, 90% were multiorgan, generating 1437 organs including 1227 that were transplanted, yielding 3.3 possible organs from each donor including 2.8 organs that were transplanted. Among donors younger than 45 years, the numbers increased to 3.7 and 3.4, respectively, and for donors older than 60 years, the numbers were 2.7 and 1.9, respectively.

CONCLUSIONS

Despite the increase in donors and organs, family refusal did not decrease, as this was the main reason for potential donor loss. Therefore it is necessary to create a regional program to promote donation.

Closed-loop control of renal perfusion pressure in physiological experiments

This paper presents the design, experimental modeling, and control of a pump-driven renal perfusion pressure (RPP)-regulatory system to implement precise and relatively fast RPP regulation in rats. The mechatronic system is a simple, low-cost, and reliable device to automate the RPP regulation process based on flow-mediated occlusion. Hence, the regulated signal is the RPP measured in the left femoral artery of the rat, and the manipulated variable is the voltage applied to a dc motor that controls the occlusion of the aorta. The control system is implemented in a PC through the LabView software, and a data acquisition board NI USB-6210. A simple first-order linear system is proposed to approximate the dynamics in the experiment. The parameters of the model are chosen to minimize the error between the predicted and experimental output averaged from eight input/output datasets at different RPP operating conditions. A closed-loop servocontrol system based on a pole-placement PD controller plus dead-zone compensation was proposed for this purpose. First, the feedback structure was validated in simulation by considering parameter uncertainty, and constant and time-varying references. Several experimental tests were also conducted to validate in real time the closed-loop performance for stepwise and fast switching references, and the results show the effectiveness of the proposed automatic system to regulate the RPP in the rat, in a precise, accurate (mean error less than 2 mmHg) and relatively fast mode (10-15 s of response time).

[Insulin glargine in intensively-treated type 1 diabetes mellitus]

OBJECTIVES

To evaluate the use of insulin glargine in intensively-treated children and adolescents. To assess the degree of patient and parent satisfaction with this treatment.

PATIENTS AND METHODS

We studied 42 patients with type 1 diabetes. There were 27 girls and 15 boys. The mean age at diagnosis was 6.8 years (range 1.2-13.2), the mean age at initiation of glargine therapy was 12.8 years (range 7.0-17.7), and the mean duration of diabetes was 6.1 years (range 2.0-11.9). Glargine indications were poor metabolic control or frequent hypoglycemia with multiple daily injections of NPH insulin, which were substituted by one dose of glargine. Patient and parent satisfaction with diabetes treatment was assessed with the scale published by Boot. ANOVA, Student's t test, Mann-Whitney and Fisher tests were applied.

RESULTS

Variables are reported as mean 6 standard deviation. After 18 months, glargine reduced hemoglobin A1c levels (7.65 % +/- 0.74 vs. 8.03 % +/- 0.69; p = 0.001), with no significant changes in insulin dose (1.03 +/- 0.19 U/kg/day vs. 1.08 +/- 0.21; p = 0.052) or body mass index SDS (standard deviation score) (+0.51 +/- 0.96 vs. 10.61 +/- 1.02; p = 0.11). Glargine also increased patient satisfaction (+44.5 +/- 18.8 points vs. -9.9 +/- 26.8; p < 0.001) and parent satisfaction (+42.0 +/- 17.9 points vs. -20.8 +/- 29.1; p < 0.001) with diabetes treatment.

CONCLUSIONS

1. Glargine insulin improves metabolic control in intensively-treated children and adolescents with type 1 diabetes. 2. Glargine also improves patient and parent satisfaction with diabetes treatment.

An improved strategy for evaluating the extent of chronic arterial baroreceptor denervation in conscious rats

There is no index or criterion of aortic barodenervation, nor can we differentiate among rats that have suffered chronic sham, aortic or sino-aortic denervation. The objective of this study was to develop a procedure to generate at least one quantitative, reproducible and validated index that precisely evaluates the extent of chronic arterial barodenervation performed in conscious rats. Data from 79 conscious male Wistar rats of about 65-70 days of age with diverse extents of chronic arterial barodenervation and used in previous experiments were reanalyzed. The mean arterial pressure (MAP) and the heart rate (HR) of all rats were measured systematically before (over 1 h) and after three consecutive iv bolus injections of phenylephrine (PHE) and sodium nitroprusside (SNP). Four expressions of the effectiveness of barodenervation (MAP lability, PHE ratio, SNP ratio, and SNP-PHE slope) were assessed with linear fixed models, three-level average variance, average separation among levels, outlier box plot analysis, and overlapping graphic analysis. The analysis indicated that a) neither MAP lability nor SNP-PHE slope was affected by the level of chronic sodium intake; b) even though the Box-Cox transformations of both MAP lability [transformed lability index (TLI)] and SNP-PHE slope [transformed general sensitivity index (TGSI), {((3-(ΔHR(SNP)-ΔHR(PHE)/ΔMAP(SNP)-ΔMAP(PHE)))(-0.4)-1)/-0.04597}] could be two promising indexes, TGSI proved to be the best index; c) TLI and TGSI were not freely interchangeable indexes for this purpose. TGSI ranges that permit differentiation between sham (10.09 to 11.46), aortic (8.40 to 9.94) and sino-aortic (7.68 to 8.24) barodenervated conscious rats were defined.

Enhanced increase of plasma sodium pump inhibitory activity to saline expansion in vagosympathectomized and anaesthetized dogs

To investigate whether plasma sodium pump inhibitory activity is controlled by cardiopulmonary and aortic baroreceptors, mean arterial pressure, right atrial pressure, sodium and water balances, plasma renin activity, plasma aldosterone concentration and plasma antinatriferic activity (PAA; plasma sodium pump inhibitory activity) were determined before, during and after Ringer volume expansion (10% of body wt) in anaesthetized dogs. Animals were studied with intact reflexes (CTR, n = 7) and after acute cervical bilateral vagosympathetic denervation (VGT, n = 8). With the exception of PAA, none of the parameters were different between groups before, during or after Ringer volume expansion. The PAA (microA cm-2) was similar for both groups before expansion and before either sham (CTR) or vagosympathectomy (VGT) was performed (CTR = 3.6 +/- 0.4 vs. VGT = 4.3 +/- 0.3). Compared to baseline, PAA at the end of the volume expansion phase increased in both groups (CTR = 6.1 +/- 0.8, P < 0.05; VGT = 9.1 +/- 0.7, P < 0.0005); however, this PAA value was significantly greater in the VGT group than in the CTR group (P < 0.01). At the end of the post-expansion phase, PAA levels returned toward baseline in both groups (CTR = 4.4 +/- 0.5 vs. VGT = 4.8 +/- 0.2; n.s. vs. baseline); however, this PAA value in the CTR group was not significantly different from its pak value. The present data confirm that PAA is increased in response to saline volume expansion, and suggest that PAA synthesis and/or release is under inhibitory vagosympathetic control during saline volume expansion.

Supranormal natriuretic response to volume expansion in vagotomized and renal-denervated rats

1. To investigate the participation of both vagal cardiopulmonary baroreceptor activity and efferent renal sympathetic nerve activity (ERSNA) in the natriuretic response to saline volume expansion (SVE), three series of experiments were undertaken in anaesthetized rats. 2. In the first two series of experiments, the natriuretic (series A) and ERSNA (series B) responses to SVE were evaluated in both sham operated and cervical bilateral vagotomized rats. The acute experiment consisted of two baseline (BL) periods, treatment (sham control (CTR) or real cervical bilateral vagotomy), a volume expansion phase (Ringer's solution, 10% bodyweight) and a postexpansion phase. The results of these two series indicate that vagotomy significantly enhances basal ERSNA (37 +/- 8%; P < 0.05 vs BL) and significantly attenuates the renal sympathoinhibitory response (by approximately 50%; P < 0.05 vs CTR) but not the natriuretic response to SVE, suggesting the potential expression of a vagotomy induced compensatory natriuretic mechanism. 3. To assess this, the natriuretic response to SVE was evaluated in chronic sham operated or renal denervated groups of rats in which vagotomy was or was not performed (series C). There were no differences among groups in either systemic haemodynamics or plasma protein concentration. Vagotomy plus chronic renal denervation induced a supranormal natriuretic and diuretic response (approximately 30%; P < 0.01) to SVE when compared with similar natriuretic and diuretic responses of the remaining groups. 4. These data support the idea that, in intact rats on a normal sodium diet, neither cardiopulmonary baroreceptors nor renal nerves are necessary for the elimination of an acute intravenous isotonic sodium load and indicate that during SVE the activation of vagal cardiopulmonary baroreceptors exerts an inhibitory effect on both ERSNA and the expression of a natriuretic mechanism. Such a natriuretic mechanism is expressed only when SVE is induced in vagotomized rats (compensating for the vagotomy mediated antinatriuretic effects of an enhanced ERSNA), but is unmasked only when, in addition, renal nerves are chronically transected. All of this offers an efficient element of safety in eliminating an acute isotonic sodium load when cardiopulmonary baroreceptors are severed.

[Risk factors for refusing kidneys in Galicia. Is it possible to increase its use?]

INTRODUCTION

Demographic changes along with an increase in the demand of organs and an increase in the expertise of transplantation teams, lead to a constant modification of donors' characteristics and, accordingly, of the supply of the organs used and refused.

OBJECTIVE

Analyze the use and refusal of kidneys generated in Galicia. Subjects and method. A follow-up of kidney donors was carried out between 1996 and 2000, studying the reasons for non extraction and refusal of kidneys and analyzing the influence that donors' characteristics have on them. In order to evaluate the risk factors of not using grafts, multiple logistic regression patterns were made, assessing odds ratios with confidence intervals at 95%.

RESULTS

836 kidneys were recovered from 433 donors, and 697 were implanted out of them. 17% of the organs extracted, a percentage approaching 25% in the two latest years, were discarded, due to the biopsy findings (27%), donor's previous conditions (22%), anatomical disorders (16%), prolonged cold ischemia (12%) or recipient not located or unsuitable (14%). The average age of refused grafts was significantly higher than that of implanted ones, in such a way that having more than 45 years old was an independent risk for refusing kidneys (OR = 1.76 and p = 0.05, for 45-59 years old; OR = 6.1 and p = 0.000, for older than 60 years old). The same happened with history of hypertension (OR = 1.59 and p = 0.044), high serum creatinine level (OR = 1.83 and p = 0.005) and positive serology for HCV (OR = 5.65 and p = 0.001) and anti-HBc (OR = 2.91 and p = 0.017).

CONCLUSIONS

Elderly donors and donors with concomitant diseases enable us to increase the number of grafts, although they also lead to an increase in refusals, which nearly amounts to 20% of the ones generated. However, more than the half were refused due to pontentially avoidable reasons and therefore these could have been valued for transplantation to limit recipients.

[Renal transplantation in the northwest of Spain: analysis of the activity in the region of Galicia]

BACKGROUND

Spain is the world leader in organ transplant rates, and the national average is maintained in the northwestern Spanish region of Galicia. However, there is no official registry recording transplantation results in this region. In this paper we report a study of patient and graft survival and risk factors among kidney transplant patients in Galicia between January 1996 and December 2000.

METHODS

Patients receiving kidney transplants in Galicia in the above period were monitored up to the end of 2001, deaths and graft losses were recorded and analysed by actuarial and Kaplan-Meier methods, and possible risk factors for death and graft loss were evaluated using Cox's proportional hazards model.

RESULTS

In the study period, 672 kidneys were transplanted, all from deceased donors. Graft and patient survival rates were respectively 80% and 94% after 1 year, and 67% and 83%, after 5 years. Two-thirds of graft losses occurred within the first year and the most common cause was vascular thrombosis (44%). Independent risk factors for graft loss were donor asystole (relative risk [RR] = 3.41, 95% confidence interval [CI]: 1.73-6.73), donor age (RR = 1.54, CI: 1.05-2.27 for 40-60-year-olds, RR = 2.59, CI: 1.66-4.07 for over-60s, relative to under-40s), donation from outside the institution in which implant was performed (RR = 1.43, CI: 1.02-2.02), acute rejection (RR = 2.32, CI: 1.63-3.22), and retransplantation (RR = 1.56, CI: 1.03-2.37). The main causes of death were infections (38%), followed by cardiovascular pathologies (30%) and tumours (11%).

CONCLUSIONS

The kidney transplant rate varies excessively within Galicia; the global rate is 50 per million inhabitants per year. Patient survival is similar to those recorded in national registers, but graft survival is deficient, apparently due to a high incidence of vascular thrombosis.