Parallel avenues in the evolution of hearts and pumping organs

Research in animal models established that tinman, a key gene in Drosophila dorsal vessel development, is an orthologue of Nkx2-5, a key gene in vertebrate cardiac development. Similarities between the arthropod dorsal vessel and vertebrate hearts are interpreted in light of concepts such as homology or convergence. We discuss this controversy in the context of the evolution of animal circulatory pumps and propose the distinction between peristaltic and chambered pumps as a fundamental parameter for evolutionary comparisons between bilaterian pumps. Neither homology nor convergence is satisfactory to explain the origins of hearts and pumping organs. Instead, we propose that animal pumps derive from parallel improvements of an ancestral, peristaltic design represented by a layer of myocytes at the external walls of primitive vessels. This paradigm unifies disparate views, impacts our understanding of bilaterian evolution and may be helpful to interpret similarities between pumping organs of phylogenetically relevant species and emerging models.

Four-year follow-up of a prospective trial of HLA and MICA antibodies on kidney graft survival

In 2002, 1329 patients with functioning transplants were prospectively tested for HLA antibodies in the 13th International Histocompatibility Workshop. Four years after testing, deceased donor graft survival among 806 patients not having antibodies in 2002 was 81% compared to 58% for 158 patients with HLA antibodies (p < 0.0001) and 72% for 69 patients with MICA antibodies (p = 0.02). Hazard ratio (HR) using death-censored graft survival from multivariate analysis of HLA antibodies was 3.3 (p < 0.00001) and 2.04 for MICA (p = 0.01). In the 14th Workshop, at 1 year follow-up, survival for 1319 patients receiving deceased donor grafts and no HLA antibodies was 96% compared to 94% for 344 patients with HLA antibodies (p = 0.0004) and 83% survival for 33 patients with MICA (p = 0.0005). HR from multivariate analysis: HLA antibodies was 3.6 (p < 0.00001) and 6.1 for MICA (p = 0.006). Twelve patients with donor specific antibodies tested by single antigen beads had a 1 year survival of 64% (p = 0.008), and 27 patients with non-donor specific 'strong' antibodies had a 66% survival (p = 0.0003) compared to 92% survival in those with no antibodies. In conclusion, these two prospective trials, after 1 and 4 years, provided strong evidence that HLA and MICA antibodies are associated with graft failure.

14th International HLA and Immunogenetics Workshop Prospective Chronic Rejection Project: a three-year follow-up analysis

The three-year follow-up of 4,144 patients of the 14th International Workshop Prospective Chronic Rejection study has reinforced the evidence that post-transplant HLA antibodies are predictive of long-term graft loss. Three years after a single testing for HLA antibodies, 10% of kidney recipients who were antibody-positive had lost their grafts, in contrast to only 5% of antibody-negative patients (p<0.0001). The adverse effect of post-transplant antibodies on graft survival was also observed in lung, heart, and liver transplants. Donor-specific antibodies and 'strong' non-DSA had stronger association with graft loss than 'moderate' non-DSA. Periodic antibody monitoring, combined with specificity and strength analysis, would help in the early identification of allograft recipients who are at high risk of graft failure.

Scuticociliate proteinases may modulate turbot immune response by inducing apoptosis in pronephric leucocytes

The role of proteinases of the histiophagous ciliate Philasterides dicentrarchi, purified by affinity chromatography in bacitracin-Sepharose, on apoptosis (programmed cell death) of turbot pronephric leucocytes (PL) was investigated. The results showed that more than 90% of proteinases purified by bacitracin-Sepharose were cysteine proteinases, which lacked significant caspase-3-like activity and generated three main gelatinolytic bands of molecular weights 36, 45 and 77 kDa as determined by gelatine-SDS-PAGE and immunoblot. Viability of PL cells after 24 h stimulation with P. dicentrarchi cysteine proteinases did not differ from that of non-stimulated cells. Apoptosis was confirmed by: (i) caspase activity, (ii) DNA fragmentation, and (iii) nucleus fragmentation. The caspase-3-like activity in PL incubated for 4h in the presence of 125, 250 and 500 microg/ml of proteinases increased in a dose-dependent fashion. The PL DNA was fragmented following 24-h exposure to P. dicentrarchi cysteine proteinases and characteristic DNA ladders consisting of multimers of approximately 180-200 pb were produced. Morphological changes, such as chromatin condensation and nucleus fragmentation, were observed under fluorescence microscopy after DAPI staining of the PL cells incubated with cysteine proteinase-incubated for 24 h. The results suggest that the pathogenic scuticociliate P. dicentrarchi may induce host leucocyte programmed cell death via the production of cysteine proteinases, as a mechanism of pathogenesis and evasion of the turbot innate immune response.

[Genital ulcers caused by sexually transmitted diseases: current therapies, diagnosis and their relevance in HIV pandemy]

The sexual transmitted pathogens associated with genital ulcers are Treponema pallidum, Haemophilus ducreyi, Calymmatobacterium granulomatis, Chlamydia trachomatis and Herpes simplex virus type 1 or 2. Although geographic differences still exist, herpetic infections prevalence is growing worldwide as the most frequent ulcerative sexual transmitted disease. The failure of the many different used guidelines in achieving a sustained reduction in the number of new cases, in particular the WHO syndromic management, leads into an over treatment of bacterial agents and missing of viral agents. This situation is also associated with poor efficacy and wasting of economical resources. Ulcerative and non-ulcerative sexual transmitted diseases are important in the world HIV pandemy because they promote HIV transmission and are also associated with the disease evolution. Portugal had until recently the highest incidence of HIV infection in Europe and that points out to importance of treating and control of both ulcerative and non-ulcerative sexual transmitted diseases in order.

HOMA, QUICKI and MFfm to Measure Insulin Resistance in Morbid Obesity

BACKGROUND

The relationship between morbid obesity (MO) and insulin resistance (IR) has been widely demonstrated. The euglycemic-hyperglycemic clamp method for diagnosis of IR is neither practical nor cost-effective for population-based studies. However, the application of mathematical models (HOMA, QUICKI and Mf(fm) indices) can be useful.

METHODS

The data from 171 patients were retrospectively evaluated. We recorded general anthropometric parameters and the basal levels of glucose, triglycerides and insulin and calculated the metabolic indexes both before surgery (Capella gastric bypass) and 6, 12, 24, 36 and 48 months after the operation.

RESULTS

Before surgery, patients could be classified according to their waist-hip ratio (WHR) into 2 groups. Group A (n = 131, 108 females and 23 males) with WHR values 1.10 +/- 0.1 SD for males and 0.94 +/- 0.1 for females (central obesity); and Group B (n = 40, 34 females and 6 males) with WHR values 0.90 +/- 0.1 for males and 0.84 +/- 0.1 for females (peripheral obesity). Group A patients showed elevated serum levels of glucose, triglycerides and insulin and high values of the HOMA index with low values of QUICKI and Mf(fm). Group B patients showed lower levels of glucose, triglycerides, insulin and HOMA index and higher values of QUICKI and Mf(fm). These abnormal levels began to decrease 6 months after bypass and the QUICKI and Mf(fm) began to increase.

CONCLUSIONS

The high baseline levels of insulin and the high prevalence of hypertension, diabetes or both conditions in patients with central obesity confirm that they suffer a metabolic syndrome, Meanwhile, patients with peripheral obesity with lower levels of chemical parameters and of the metabolic indices suffer peripheral resistance against insulin. Clinical application of these mathematical indices can be useful in patients with MO; they are easily performed and lack the high costs and risks associated with the clamp technique.

Homocysteine metabolism, hyperhomocysteinaemia and vascular disease: an overview

Hyperhomocysteinaemia has been regarded as a new modifiable risk factor for atherosclerosis and vascular disease. Homocysteine is a branch-point intermediate of methionine metabolism, which can be further metabolised via two alternative pathways: degraded irreversibly through the transsulphuration pathway or remethylated to methionine by the remethylation pathway. Both pathways are B-vitamin-dependent. Plasma homocysteine concentrations are determined by nongenetic and genetic factors. The metabolism of homocysteine, the role of B vitamins and the contribution of nongenetic and genetic determinants of homocysteine concentrations are reviewed. The mechanisms whereby homocysteine causes endothelial damage and vascular disease are not fully understood. Recently, a link has been postulated between homocysteine, or its intermediates, and an alterated DNA methylation pattern. The involvement of epigenetic mechanisms in the context of homocysteine and atherosclerosis, due to inhibition of transmethylation reactions, is briefly overviewed.

Effect of tibolone on cytochrome c oxidase I, beta-2-microglobulin and vascular endothelial growth factor gene expression in the lower urinary tract of castrated rats

INTRODUCTION

The objective of this study was to evaluate the effect of tibolone on cytochrome oxidase I (COX I), beta-2-microglobulin (B2M) and vascular endothelial growth factor (VEGF) gene expression in the lower urinary tract of castrated rats. These genes are related to cell energy, cellular immunity and vascularization processes.

METHODS

Fifty adult castrated rats remained at rest for 28 days. Thereafter they were randomly divided into two groups of 25 animals each. The lower urinary tract (bladder and urethra) was extracted in animals of one group and the other group received tibolone at a dose of 0.25 microg/animal/day for another 28 days followed by removal of the lower urinary tract. Total RNA was extracted from animals of both groups, forming two pools. After RT-PCR (reverse transcriptase polymerase chain reaction), expression of COX I, B2M and VEGF genes was evaluated by agarose gel electrophoresis, visualized by UV illumination.

RESULTS

Expression of the three genes (COX I, B2M and VEGF) was greater in the group treated with tibolone.

CONCLUSION

The use of tibolone increases the expression of COX, B2M and VEGF genes in the lower urinary tract as compared with that in castrated rats.

Morbid obesity, hypertensive disease and the renin-angiotensin-aldosterone axis

BACKGROUND

Resistance to insulin and secondary hyperinsulinemia seem to be the putative link between morbid obesity (MO) and hypertensive disease (HD). Adipose tissue can secrete leptin and angiotensinogen, among other substances. Leptin activates the sympathetic nervous system, leading to HD. Angiotensinogen is a substrate for renin, therefore taking part in the renin-angiotensin-aldosterone axis and the regulation of blood pressure. In MO, both hypertrophy and hyperplasia of the adipocytes lead to an increase in the secretion of both substances, leading to loss of the equilibrium between the levels of both hormones. The aim of the present study was to evaluate these abnormalities and their potential reversibility following bariatric surgery.

METHODS

Data from 100 patients with MO was retrospectively evaluated. Anthropometric data, the plasma renin activity (PRA), plasma levels of aldosterone, ACE, potassium and sodium were collected both prior to surgery and 6, 12, 24 and 36 months after surgery.

RESULTS

The waist-hip ratio (WHR) before surgery allowed classification of our patients in two groups: central obesity (WHR > or =0.90 in men and > or =0.85 in women); peripheral obesity (WHR <0.90 in men and <0.85 in women). In patients with central obesity, high levels of PRA, aldosterone and ACE with sodium retention and potassium loss and high insulin levels, were found. These changes were not found in patients with peripheral obesity. After gastric bypass, these abnormalities tended to disappear, mainly in the first 6 months.

CONCLUSIONS

The reduction of BMI and WHR after gastric bypass confirmed this operation to be effective against MO. The high basal levels of insulin and the high rate of HD and diabetes in patients with central obesity seem to indicate that they suffer a metabolic syndrome with significant hormonal imbalances and sodium retention. Patients with peripheral obesity only showed a peripheral resistance against insulin, probably with a shorter duration of the hormonal action, but they did not show hormonal abnormalities or sodium retention. After gastric bypass these abnormal hormone levels tended to normalize.

Humoral and cellular responses to cow milk proteins in patients with milk-induced IgE-mediated and non-IgE-mediated disorders

BACKGROUND

Cow milk allergy (CMA) is one of the most common food allergies in childhood. Patients with CMA present with a wide range of immunoglobulin (Ig)E- and non-IgE-mediated clinical syndromes. Limited information is known about the specific humoral and cellular responses to cow milk proteins in these various forms of CMA.

OBJECTIVE

The aim of the study was to determine IgE, IgA, IgG1 and IgG4 antibody levels and lymphocyte proliferative responses to the major cow milk allergens in patients with IgE- and non-IgE-mediated CMA.

METHODS

One hundred and forty cow milk allergic patients, 6 months to 22 years of age, were included in the study. One hundred and thirteen patients had IgE-mediated CMA, 11 had milk protein-induced enterocolitis syndrome and 16 had allergic eosinophilic gastroenteritis. Twenty-one patients without food allergy, 8 months to 18 years of age, served as controls. Serum IgE, IgA, IgG1 and IgG4 antibodies to alpha-, beta-, and kappa-casein, alpha-lactalbumin and beta-lactoglobulin were measured using enzyme-linked immunosorbent assays. For a subset of these patients, we performed lymphocyte proliferation assays to the various milk allergens.

RESULTS

Patients with IgE-mediated CMA had higher specific IgE concentrations to casein compared with whey proteins (P < 0.001). In this group of patients, there was a positive correlation between IgE levels and levels of the other isotypes for all four milk proteins (P < 0.001). In general, the caseins were the more allergenic and antigenic proteins in all groups of patients. Patients with enterocolitis syndrome produced less milk protein-specific IgG4 (P < 0.05) and had a trend for higher IgA antibody levels when compared to the control group. Lymphocyte proliferative responses in all groups with CMA were significantly higher than controls (P < 0.05), although this response was similar in patients with IgE- and non-IgE-mediated CMA.

CONCLUSION

There is a distinct pattern of humoral antibody response in the different forms of CMA. Patients with IgE-mediated CMA have an elevated polyisotypic response to cow milk protein. The relative lack of specific IgG4 production in patients with enterocolitis syndrome may be involved in the pathogenesis of the disease. In general, caseins appear to be the predominant allergen in patients with CMA.

Functional analysis of genetic variants in the human concentrative nucleoside transporter 3 (CNT3; SLC28A3)

The human concentrative nucleoside transporter, CNT3 (SLC28A3), plays an important role in mediating the cellular entry of a broad array of physiological nucleosides and synthetic anticancer nucleoside analog drugs. As a first step toward understanding the genetic basis for interindividual differences in the disposition and response to antileukemic nucleoside analogs, we examined the genetic and functional diversity of CNT3. In all, 56 variable sites in the exons and flanking intronic region of SLC28A3 were identified in a collection of 270 DNA samples from US populations (80 African-Americans, 80 European-Americans, 60 Asian-Americans, and 50 Mexican-Americans). Of the 16 coding region variants, 12 had not been previously reported. Also, 10 resulted in amino-acid changes and three of these had total allele frequencies of >/=1%. Nucleotide diversity (pi) at nonsynonymous and synonymous sites was estimated to be 1.81 x 10(4) and 18.13 x 10(4), respectively, suggesting that SLC28A3 is under negative selection. All nonsynonymous variants, constructed by site-directed mutagenesis and expressed in Xenopus laevis oocytes, transported purine and pyrimidine model substrates, except for c. 1099G>A (p. Gly367Arg). This rare variant alters an evolutionarily conserved site in the putative substrate recognition domain of CNT3. The presence of three additional evolutionarily conserved glycine residues in the vicinity of p. Gly367Arg that are also conserved in human paralogs suggest that these glycine residues are critical in the function of the concentrative nucleoside transporter family. The genetic analysis and functional characterization of CNT3 variants suggest that this transporter does not tolerate nonsynonymous changes and is important for human fitness.

Morbid obesity and gastric bypass surgery: biochemical profile

BACKGROUND

Morbid obesity (MO) and the pathologies associated with it constitute an important public health problem, accounting for 7% of the health expenditure in industrialized countries. An important percentage of this expense is attributed to the different biochemical tests performed in these patients, who suffer from several metabolic derangements. We evaluated the basic biochemical abnormalities in MO patients and their reversibility by weight loss after gastric bypass, to standardize the surveillance of the different metabolic abnormalities in obese patients.

METHODS

By a retrospective analysis on 125 patients operated in our hospital, we evaluated anthropometric and biochemical data before and 1, 3, 6, 12 and 24 months after gastric bypass.

RESULTS

Preoperatively hyperinsulinemia, hyperglycemia, dyslipidemia and hypertensive disease were present, and began to improve 1 and 3 months after surgery (although not significantly) and significantly at 6, 12 and 24 months after it. We also observed deficient protein nutrition and a deficiency of micronutrients both before bypass and during the follow-up.

CONCLUSION

After gastric bypass, a marked decrease in insulin occurred, with normalization of blood pressure and the biochemical parameters associated with the metabolic syndrome. We propose a biochemical follow-up protocol for MO patients.

Does electrical stimulation of the pelvic floor make any change in urodynamic parameters? When to expect a cure and improvement in women with stress urinary incontinence?

OBJECTIVE

Our study aimed at determining the effects of pelvic floor electrical stimulation assessed by the number of leakages per day recorded in a voiding diary over 90 days of treatment and urodynamic parameters.

STUDY DESIGN

This prospective study was carried out with 34 patients presenting stress urinary incontinence who were treated and evaluated by voiding diaries and urodynamic tests. The primary outcome measure was the number of leakages during the 90 days of treatment. Urodynamic tests were performed before and after treatment.

RESULTS

In our series, average and maximum flow rates and residual urine volume were within normal range in all subjects before and after treatment. Maximum urethral closure pressure and functional profile length on urethral pressure profiles did not change after treatment. In the cystometry, bladder capacities at the first (p < 0.0082) and maximum sensations (p < 0.01) improved significantly after treatment. During the 90 days of treatment, we observed a gradual drop in the number of leakages. This decrease began around day 22. It dropped in half around day 45, tending to zero close to day 90 of treatment (p < 0.01).

CONCLUSIONS

The number of incontinent leakage dropped to half around the 8th week, and on average, there was a tendency of the patients to be cured after the 12th week of treatment. At urodynamic studies we observed a significant increase in bladder capacity at the first desire to void and in the maximum cystometric capacity.

Urodynamic alterations after pelvic floor exercises for treatment of stress urinary incontinence in women

The following study improves the effectiveness of pelvic floor exercise in women with stress urinary incontinence. A group of 27 women with stress urinary incontinence performed specific pelvic floor exercises twice a week for 45 minutes under a therapist's supervision for a period of 12 weeks. This group had urodynamic and urethral pressure profile studies and filled in a daily diary. The patients self-evaluated their symptoms. After the therapy, the urodynamic and urethreal pressure profile studies were repeated and the results were: 66.7% patients were self-evaluated as cured; 14.8% improved and 18.5% unchanged. The urodynamic results showed that 48.2 % of the patients did not have urinary loss, however, 51,8% of the patients that had a loss showed an increase in vesicle volume, and only 7.3% remained unchanged. The results show that pelvic floor exercises are an effective and low cost treatment for stress urinary incontinence rehabilitation.

5,10-Methylenetetrahydrofolate reductase 677C-->T and 1298A-->C mutations are genetic determinants of elevated homocysteine

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR) is one of the main regulatory enzymes of homocysteine metabolism. Elevated plasma total homocysteine (tHcy) is a major risk for cardiovascular disease. A common 677C-->T mutation in the MTHFR gene results in decreased enzymic activity, and contributes to increased plasma tHcy, in association with low plasma folate. A recently described 1298A-->C mutation in the MTHFR gene clearly reduces MTHFR activity (although to a lesser extent than the 677C-->T) but its effect on plasma tHcy levels is not yet clear.

AIM

To investigate the frequency of these two MTHFR polymorphisms in a Portuguese population, and to correlate the MTHFR genotype with the biochemical phenotype at the level of homocysteine and folate concentrations.

DESIGN

Prospective population survey.

METHODS

We studied 117 healthy volunteers (71 females, 46 males). The 677C-->T and 1298A-->C mutations were screened by PCR-RFLP. Levels of plasma tHcy and folate, and red blood cell folate, were determined.

RESULTS

The allele frequencies of the 677C-->T and 1298A-->C mutations were 0.33 and 0.28, respectively. Homozygotes for the 677C-->T mutation had significantly elevated plasma tHcy and RBC folate levels and significantly lowered plasma folate concentrations than subjects without the mutation. The 1298A-->C mutation showed a significant effect on plasma tHcy, but not on plasma folate or RBC folate levels.

DISCUSSION

The observed 677T allele frequency is not consistent with the idea of a north-south gradient as previously suggested. The 1298A-->C mutation is common in Portugal. Both MTHFR mutations showed effects on plasma tHcy levels.

RenaGel efficacy in severe secondary hyperparathyroidism

BACKGROUND

Haemodialysis patients frequently have simultaneous hypercalcemia and hyperphosphatemia, posing a therapeutic dilemma for the traditional calcium--and aluminum--based binders. RenaGel (sevelamer hydrochloride) is an effective phosphate binder without changes in serum calcium or aluminum levels. However being an expensive medication it is currently used mainly for patients with moderate to severe secondary hyperparathyroidism. However most of the previous studies have not included patients with severe secondary hyperparathyroidism.

METHODS

Our purpose is to determine RenaGel binder efficacy in haemodialysis patients with severe secondary hyperparathyroidism. As a secondary purpose we have followed the variations of parathyroid hormone, serum calcium, serum lipids [low- and high-density lipoprotein cholesterol, triglycerides and Lipoprotein(a)], uric acid and bicarbonate. All phosphate binders previously used were suspended one week before RenaGel prescription. Our study included 18 adult haemodialysis patients, with PTHi of 810 +/- 330 pg/ml after the "pre-treatment" washout. The binder was administered during 12 weeks, beginning with a mean dose of 2.4 +/- 0.4 g daily and adjusted to obtain serum phosphorus under 6.5 mg/dl (at the end of the study, the mean RenaGel dose was 2.8 +/- 0.6 g daily.

RESULTS

The mean changes after RenaGel in serum phosphorus was -0.7 +/- 1.5. mg/dl (P < 0.05), in serum calcium was 0.5 +/- 1.0 mg/dl (P < 0.05) and in calcium x phosphate product of -4.0 +/- 12.4 mg/dl (P = NS). "Post-treatment" the PTHi levels remained stable (820 +/- 360 pg/ml vs 810 +/- 330) but serum alkaline phosphatase increased (14.3 +/- 14.4 U/l; P < 0.01). LDL cholesterol serum levels decreased by -35 +/- 10 mg/dl (P < 0.01), HDL cholesterol showed a trend to increase (3.0 +/- 8.1 U/l; P = NS), triglycerides decreased by 38 +/- 56 mg/dl (P < 0.05) and Lipoprotein(a) remained stable. Serum albumin increased by 0.1 +/- 0.2 g/L (P < 0.05), uric acid decreased -0.8 +/- 1.2 mg/dl (P < 0.05) and bicarbonate remained unchanged.

CONCLUSIONS

RenaGel is an effective phosphate binder, even in haemodialysis patients with severe secondary hyperparathyroidism. The lipid profile improved with the treatment, with the exception of Lipoprotein(a) stabilization. Selection of patients with severe secondary hyperparathyroidism at the beginning of RenaGel disposal, for economic reasons is debatable, but could be correct.