Trophoblasts, invasion, and microRNA

MicroRNAs (miRNAs) have recently become essential actors in various fields of physiology and medicine, especially as easily accessible circulating biomarkers, or as modulators of cell differentiation. To this respect, terminal differentiation of trophoblasts (the characteristic cells of the placenta in Therian mammals) into syncytiotrophoblast, villous trophoblast, or extravillous trophoblast constitutes a good example of such a choice, where miRNAs have recently been shown to play an important role. The aim of this review is to provide a snapshot of what is known today in placentation mechanisms that are mediated by miRNA, under the angles of materno–fetal immune dialog regulation, trophoblast differentiation, and angiogenesis at the materno–fetal interface. Also, two aspects of regulation of these issues will be highlighted: the part played by oxygen concentration and the specific function of imprinted genes in the developing placenta.

Landscape of transcriptional deregulations in the preeclamptic placenta

Preeclampsia is a pregnancy disease affecting 5 to 8% of pregnant women and a leading cause of both maternal and fetal mortality and morbidity. Because of a default in the process of implantation, the placenta of preeclamptic women undergoes insufficient vascularization. This results in placental ischemia, inflammation and subsequent release of placental debris and vasoactive factors in the maternal circulation causing a systemic endothelial activation. Several microarray studies have analyzed the transcriptome of the preeclamptic placentas to identify genes which could be involved in placental dysfunction. In this study, we compared the data from publicly available microarray analyses to obtain a consensus list of modified genes. This allowed to identify consistently modified genes in the preeclamptic placenta. Of these, 67 were up-regulated and 31 down-regulated. Assuming that changes in the transcription level of co-expressed genes may result from the coordinated action of a limited number of transcription factors, we looked for over-represented putative transcription factor binding sites in the promoters of these genes. Indeed, we found that the promoters of up-regulated genes are enriched in putative binding sites for NFkB, CREB, ANRT, REEB1, SP1, and AP-2. In the promoters of down-regulated genes, the most prevalent putative binding sites are those of MZF-1, NFYA, E2F1 and MEF2A. These transcriptions factors are known to regulate specific biological pathways such as cell responses to inflammation, hypoxia, DNA damage and proliferation. We discuss here the molecular mechanisms of action of these transcription factors and how they can be related to the placental dysfunction in the context of preeclampsia.

[Endothelial dysfunction: role in the maternal syndrome of preeclampsia and long-term consequences for the cardiovascular system]

Preeclampsia is a pregnancy disorder being a leading cause of maternal and fetal mortality and morbidity. It is a complex multisystem disease characterized by hypertension and proteinuria. In preeclampsia the placenta releases factors into the maternal circulation which cause a systemic endothelial dysfunction. Here, we review data demonstrating the central role played by the endothelium in the development of the maternal syndrome of preeclampsia. We present also original data showing how circulating factors present in the plasma of preeclamptic women can alter the transcriptome of endothelial cells. The expression of genes involved in essential functions such as vasoregulation, oxidative stress, apoptosis and cell proliferation show differential expression when endothelial cells are exposed to preeclamptic or normal pregnancy plasma. We conclude by discussing the growing evidences that the alterations of the endothelium during preeclampsia are linked to an increased risk of cardiovascular diseases latter on life. Therefore, a better understanding of the modifications undergone by the endothelial cells during preeclampsia is essential to develop new therapeutic approaches to both, manage preeclampsia and to prevent the long-term sequelae of the disease on women cardiovascular system.

Prototype of an auto-calibrating, context-aware, hybrid brain-computer interface

We present the prototype of a context-aware framework that allows users to control smart home devices and to access internet services via a Hybrid BCI system of an auto-calibrating sensorimotor rhythm (SMR) based BCI and another assistive device (Integra Mouse mouth joystick). While there is extensive literature that describes the merit of Hybrid BCIs, auto-calibrating and co-adaptive ERD BCI training paradigms, specialized BCI user interfaces, context-awareness and smart home control, there is up to now, no system that includes all these concepts in one integrated easy-to-use framework that can truly benefit individuals with severe functional disabilities by increasing independence and social inclusion. Here we integrate all these technologies in a prototype framework that does not require expert knowledge or excess time for calibration. In a first pilot-study, 3 healthy volunteers successfully operated the system using input signals from an ERD BCI and an Integra Mouse and reached average positive predictive values (PPV) of 72 and 98% respectively. Based on what we learned here we are planning to improve the system for a test with a larger number of healthy volunteers so we can soon bring the system to benefit individuals with severe functional disability.

Resolution of diabetes mellitus and metabolic syndrome in normal weight 24-29 BMI patients with One Anastomosis Gastric Bypass

INTRODUCTION

Diabetes mellitus type 2 (DMT2) is a major cause of death in the world. The medical therapy for this disease has had enormous progress, but it still leaves many patients exposed to the complications developed from the disease. It is well known the beneficial effects of bariatric surgery in obese diabetic patients, however it is important to investigate if the same principles of bariatric surgery that improve diabetes in obese patients, could be applied to non obese normal weight diabetics.

MATERIAL AND METHODS

Thirteen diabetic patients operated by One Anastomosis Gastric Bypass (BAGUA), were evaluated in the preoperative period and 1,3 and 6 months after surgery. Body weight and composition, Fasting Plasma Glucose, HbA1c levels, blood pressure and serum lipids levels were analyzed, as well as the monitoring of the immediate postoperative treatment necessities for Diabetes and other metabolic syndrome comorbidities.

RESULTS

After the surgery the 77% of the patients resolves its T2DM, 46% from surgery, and rest noted an significant improvement of the disease in spite of having a C peptide level near to zero some of the patients. The comorbidities, mainly hypertension and lipid abnormalities experience improvement early. All patients reduce their weight and the amount of fat mass until values consistent with their age and height.

CONCLUSIONS

The One Anastomosis Gastric Bypass leads to resolution or improvement of T2DM in non obese normal weight patients. The best results are obtained in patients with few years of diabetes, without or short term use of insulin treatment and high C-peptide levels.

Prevalence of thoracic vertebral fractures in Spanish patients hospitalized in Internal Medicine Departments. Assessment of the clinical inertia. (PREFRAMI study)

PURPOSE

To study the prevalence of vertebral fractures (VF), the associated risk factors and the degree of diagnosis and prescription upon discharge in a series of hospitalized medical patients ≥50 years of age.

METHODS

A cross-sectional, multicentre and observational study in which a prevalence cut-off was carried out concerning patients admitted to six Internal Medicine departments in Malaga (Spain). The main variables were the existence of a fracture in the spine lateral x-ray, the inclusion of the diagnosis of a fracture in the discharge report, and the establishment of anti-osteoporotic treatment at discharge.

RESULTS

254 patients were included (mean age 66.4±14.9 years). The prevalence of VF was of 14.2% (36 cases). Patients with VF presented with a higher mean age, compared to those without VF (70.14 vs. 65.7 years) (p=0.035). The means contrast for the FRAX index variable (major osteoporotic and hip fracture), grouping according to the presence of VF, did not show any statistical significance (p=0.369 and p=0.788, respectively). Only in 8.3% of the discharge reports of patients with VF had the diagnosis of VF and/or osteoporosis been recorded and the prescription of anti-osteoporotic drugs been included.

CONCLUSIONS

A high prevalence of asymptomatic VF is verified in medical inpatients ≥50 years of age. The FRAX index did not turn out to be predictive of the presence of VF in this population. There is an underdiagnosis of osteoporotic VF in the coding at hospital discharge. Action protocols are necessary to avoid clinical inactivity regarding this entity.

Evaluation of PSA testing by general practitioners: regional study in the autonomic Community of Valencia

OBJECTIVES

The aim of the study is to compare the use of PSA testing among general practitioners (GPs).

METHODS

The number of PSA tests ordered by general practitioners in the years 2008-2009 was examined in a cross-sectional study of nine health districts of Spain. The percentage of PSA ordered to men younger than 50 (PSA<50/PSAtotal) and 40 years (PSA<40/PSAtotal) was calculated. The percentage of men over 50 years who were attended was also calculated and this data was compared with the number of PSA ordered to this population. For two of the departments, these data were also compared between GPs and urologists.

RESULTS

PSA testing in 2009 is higher than 2008 in seven health districts. PSA testing in men younger than 50 years was increased along the period of the study and in men younger than 40 years remained steady. The differences between the values of the indicators for urologists and GPs are significant.

CONCLUSIONS

The number of PSA tests and the percentage performed to men younger 50 years has been increasing and the variability is high. These data are suggestive for interventions focused on PSA testing and prostate cancer screening in primary care settings.

Compositional properties and thermal adaptation of SRP-RNA in bacteria and archaea

Previous studies have reported a positive correlation between the GC content of the double-stranded regions of structural RNAs and the optimal growth temperature (OGT) in prokaryotes. These observations led to the hypothesis that natural selection favors an increase in GC content to ensure the correct folding and the structural stability of the molecule at high temperature. To date these studies have focused mainly on ribosomal and transfer RNAs. Therefore, we addressed the question of the relationship between GC content and OGT in a different and universally conserved structural RNA, the RNA component of the signal recognition particle (SRP). To this end we generated the secondary structures of SRP-RNAs for mesophilic, thermophilic, and hyperthermophilic bacterial and archaeal species. The analysis of the GC content in the stems and loops of the SRP-RNA of these organisms failed to detect a relationship between the GC contents in the stems of this structural RNA and the growth temperature of bacteria. By contrast, we found that in archaea the GC content in the stem regions of SRP-RNA is highest in hyperthermophiles, intermediate in thermophiles, and lower in mesophiles. In these organisms, we demonstrated a clear positive correlation between the GC content of the stem regions of their SRP-RNAs and their OGT. This correlation was confirmed by a phylogenetic nonindependence analysis. Thus we conclude that in archaea the increase in GC content in the stem regions of SRP-RNA is an adaptation response to environmental temperature.

Haemostatic effects of adrenaline-lidocaine subcutaneous infiltration at donor sites

This study sought methods in burn surgery to reduce postoperative pain and blood loss at donor sites. A prospective, randomised, controlled, blinded trial included 56 people undergoing burn surgery, divided into two groups. Both groups received subcutaneous infiltration at donor sites, with either 1:500,000 adrenaline solution containing added lidocaine or with 0.45% normal saline (controls). Outcome measurements included amount of intraoperative bleeding, need for electrocautery, days the hydrocolloid dressing remained on donor sites, percentage of re-epithelialised skin at donor sites 1 week after surgery and viability of skin grafts. Results indicated that subcutaneous adrenaline-lidocaine infiltration at donor sites reduced intraoperative bleeding, decreased postoperative pain, shortened the duration of surgery and general anaesthesia and accelerated re-epithelialisation at the donor site. The overall graft take in both groups was similar.

A hierarchical analysis of transcriptome alterations in intrauterine growth restriction (IUGR) reveals common pathophysiological pathways in mammals

Intra-uterine growth restriction (IUGR) is a frequent disease, affecting up to 10% of human pregnancies and responsible for increased perinatal morbidity and mortality. Moreover, low birth weight is an important cause of the metabolic syndrome in the adult. Protein depletion during the gestation of rat females has been widely used as a model for human IUGR. By transcriptome analysis of control and protein-deprived rat placentas, we were able to identify 2543 transcripts modified more than 2.5 fold (1347 induced and 1196 repressed). Automatic functional classification enabled us to identify clusters of induced genes affecting chromosome structure, transcription, intracellular transport, protein modifications and apoptosis. In particular, we suggest the existence of a complex balance regulating apoptosis. Among repressed genes, we noted several groups of genes involved in immunity, signalling and degradation of noxious chemicals. These observations suggest that IUGR placentas have a decreased resistance to external aggression. The promoters of the most induced and most repressed genes were contrasted for their composition in putative transcription factor binding sites. There was an over-representation of Zn finger (ZNF) proteins and Pdx1 (pancreatic and duodenal homeobox protein 1) putative binding sites. Consistently, Pdx1 and a high proportion of ZNF genes were induced at the transcriptional level. A similar analysis of ZNF promoters showed an increased presence of putative binding sites for the Tata box binding protein (Tbp). Consistently again, we showed that the Tbp and TBP-associated factors (Tafs) were up-regulated in IUGR placentas. Also, samples of human IUGR and control placentas showed that human orthologous ZNFs and PDX1 were transcriptionally induced, especially in non-vascular IUGR. Immunohistochemistry revealed increased expression of PDX1 in IUGR human placentas. In conclusion, our approach permitted the proposition of hypotheses on a hierarchy of gene inductions/repressions leading to massive transcriptional alterations in the IUGR placenta, in humans and in rodents.

Periannular complications in infective endocarditis involving prosthetic aortic valves

The periannular extension of infection in prosthetic valve endocarditis (PVE) is a serious complication of infective endocarditis associated with high mortality. Periannular lesions in PVE occasionally rupture into adjacent cardiac chambers, leading to aortocavitary fistulae and intracardiac shunting. It is unknown whether the prognosis of patients with aortocavitary fistulae is worse than that of those with nonruptured abscesses. The aims of this study were to determine the distinctive clinical characteristics of patients with PVE and either aortocavitary fistulization or nonruptured abscesses. In a retrospective multicenter study of >872 PVE episodes, 150 patients (17%) with periannular complications in PVE in the aortic position were identified (29 with aortocavitary fistulization and 121 with nonruptured abscesses). Early-onset PVE was present in 73 patients (49%). Rates of heart failure (p = 0.09), ventricular septal defect (p <0.01), and third-degree atrioventricular block (p = 0.07) were higher in patients with fistulization. Surgical treatment was undertaken in 128 patients (83%). In-hospital mortality in the overall population was 39%. Multivariate analysis identified heart failure (odds ratio [OR] 3.3, 95% confidence interval [CI] 1.6 to 6.8), renal failure (OR 2.5, 95% CI 1.2 to 5.2), and co-morbidity (OR 2.4, 95% CI 1.1 to 5.1) as independent risk factors for death. Fistulous tract formation was not associated with increased in-hospital mortality (OR 1.6, 95% CI 0.7 to 3.7). The actuarial 5-year survival rate in surgical survivors was 100% in patients with fistulae and 78% in patients with nonruptured abscesses (log-rank p = 0.14). In conclusion, aortocavitary fistulous tract formation in PVE complicated with periannular complications is associated with higher rates of heart failure, ventricular septal defect, and atrioventricular block than nonruptured abscesses. Despite the frequent complications, fistulous tract formation in the current era of infective endocarditis is not an independent risk factor for mortality.

Periannular complications in infective endocarditis involving native aortic valves

The extension of infection in native valve infective endocarditis (IE) from valvular structures to the periannular tissue is incompletely understood. It is unknown, for example, whether the prognosis of patients with aortocavitary fistulae is worse than that of those with nonruptured abscesses. The aims of this study were to determine the distinct clinical characteristics of patients with aortocavitary fistulae and nonruptured abscesses in native valve IE and to evaluate the impact of fistulization on the outcomes of patients with native aortic valve IE complicated with periannular lesions. In a retrospective multicenter study of 2,055 native valve IE episodes, 201 patients (9.8%) with periannular complications in aortic valve IE were identified (46 with aortocavitary fistulization and 155 with nonruptured abscesses). Rates of heart failure (p = 0.07), ventricular septal defect (p <0.001), and third-degree atrioventricular block (p = 0.07) were higher in patients with fistulization. Surgical treatment was undertaken in 172 patients (86%), and in-hospital mortality in the overall population was 29%. Multivariate analysis identified age >60 years (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.3 to 5.2), renal failure (OR 3.0, 95% CI 1.5 to 6.0), and moderate or severe heart failure (OR 2.5, 95% CI 1.2 to 5.2) as independent risk factors for death. There was a trend toward increased in-hospital mortality in patients with aortocavitary fistulae (OR 1.5, 95% CI 0.7 to 3.0). The actuarial 5-year survival rate in surgical survivors was 80% in patients with fistulae and 92% in patients with nonruptured abscesses (log-rank p = 0.6). In conclusion, aortocavitary fistulous tract formation in the setting of native valve IE is associated with higher rates of heart failure, ventricular septal defect, and atrioventricular block than nonruptured abscess. Despite these higher rates of complications, fistulous tract formation in the current era of IE is not an independent risk factor for mortality.

Conditional inactivation of the murine serum response factor in the pancreas leads to severe pancreatitis

The Serum Response Factor (SRF) is widely expressed transcription factor acting at the confluence of multiple signaling pathways and has been implicated in the control of differentiation, growth, and cell death. In the present study, we found that SRF is expressed in the developing and adult pancreas. To explore the possible role of SRF in this organ, we have generated mutant mice with conditional disruption of the Srf gene. Such mutants presented normal development of both the exocrine and endocrine pancreas indicating that SRF is dispensable for pancreas ontogenesis. However, after weaning, these mice developed profound morphological alterations of the exocrine pancreas, which were reminiscent of severe pancreatitis. In these mice, massive acinar injury, Nuclear Factor Kappa B activation and proinflammatory cytokines release led to complete destruction of the exocrine pancreas and its replacement by adipose tissue. Despite these changes, the organization and function of the endocrine islets of Langerhans remained well-preserved. This new animal model of spontaneous pancreatitis could prove a valuable tool to gain further insight into the physiopathology of this disease.

Interplay between FGF10 and Notch signalling is required for the self-renewal of pancreatic progenitors

Recent studies have shown that persistent expression of FGF10 in the developing pancreas of transgenic mice results in enhanced and prolonged proliferation of pancreatic progenitors, pancreatic hyperplasia and impaired pancreatic differentiation. These studies have also suggested that FGF10 prevents the differentiation of pancreatic progenitors by maintaining persistent Notch signalling. Here, we provide experimental evidence sustaining the capacity of FGF10 to induce the proliferation of pancreatic precursors, while preventing their differentiation. Using explant cultures of E10.5 isolated dorsal pancreatic epithelium, we found that FGF10 maintained Notch activation and induced the expansion of pancreatic precursors while blocking their differentiation. In addition, by using a gamma-secretase inhibitor, we were able to down-regulate the expression of Hes1, a target gene of the Notch pathway in explant cultures of pancreatic epithelium treated with FGF10. In such explants, the effect of FGF10 on the proliferation and maintenance of pancreatic progenitors was suppressed. These results demonstrate that activation of the Notch pathway is required as a downstream mediator of FGF10 signalling in pancreatic precursor cells.

Quantification of the drawing of an Archimedes spiral through the analysis of its digitized picture

We have developed a new quantitative analysis of spiral drawing that is able to evaluate any spiral execution and it has not temporal or spatial limitations in the obtaining of specimens. Thirty-one patients with action tremor and 24 control subjects were asked to draw an Archimedes spiral over a print template. Specimens were scanned and then treated through a semiautomatic computer program that reconstructs the temporal sequence of the spiral drawing by the subject. The spirals were first analysed by means of the cross-correlation coefficient with the spiral template. Secondly, the mean and the standard deviation of the distance between each point of the spiral drawing and the corresponding point of the spiral model were determined. Finally, the reconstructed spiral was analysed using the Fourier Transform. Its results were interpreted with the aid of a computer model of a tremulous spiral. The experimental variables were greater in the patients group respect to age-matched controls. There was also a high linear correlation between them and the clinical score given by three neurologists. Finally, Receiver Operating Characteristic (ROC) curves analysis shown that the method classified the spirals better than human ratters.

Dysphagia as the sole manifestation of myasthenia gravis

Three patients are described who had dysphagia as the sole manifestation of myasthenia gravis. Severity ranged from the need to be fed by nasogastric tube to moderate dysphagia requiring only diet change. Oesophageal manometry was carried out in two patients and showed generalised weakness of peristaltic contractions which included the smooth muscle part of the oesophagus. These disturbances worsened with repeated swallows. They were partly reversed by intravenous edrophonium and by rest. Repetitive nerve stimulation was normal in all three patients, but stimulated single fibre EMG of the frontalis muscle showed that all had impairment of neuromuscular transmission. Anti-AChR antibodies were found in only one patient. The most affected patient was treated with pyridostigmine, plasmapheresis, and high dose prednisone. The remaining two patients received only oral anticholinesterases.

Aorto-cavitary fistulous tract formation in infective endocarditis: clinical and echocardiographic features of 76 cases and risk factors for mortality

AIMS

To investigate the clinical features, echocardiographic characteristics, management, and prognostic factors of mortality of aorto-cavitary fistulization (ACF) in infective endocarditis (IE). Extension of infection in aortic valve IE beyond valvular structures may result in peri-annular complications with resulting necrosis and rupture, and subsequent development of ACF. Aorto-cavitary communications create intra-cardiac shunts, which may result in further clinical deterioration and haemodynamic instability.

METHODS AND RESULTS

In a retrospective multi-centre study over 4681 episodes of IE, a total of 76 patients with ACF [1.6%, confidence interval (CI) 95%: 1.2-2.0%] diagnosed by echocardiography or during surgery were identified. Fistulae were found in 1.8% of cases of native valve IE and in 3.5% of cases of prosthetic valve IE from the general population and in 0.4% of drug abusers. PVE was present in 31 (41%) cases of ACF. Transthoracic and transoesophageal echocardiography detected the fistulous tracts in 53 and 97% of cases, respectively. Peri-annular abscesses were detected in 78% of cases, fistulae originated in similar rates from the three sinuses of Valsalva, and the four cardiac chambers were equally involved in the fistulous tracts. Heart failure (HF) developed in 62% of cases and surgery was performed in 66 (87% CI 95% 77-93%) patients with a mortality of 41% (95% CI 30-53%) in the overall population. Multivariate analysis identified HF (OR 3.4, CI 95% 1.0-11.5), prosthetic IE (OR 4.6, CI 95% 1.4-15.4) and urgent or emergency surgical treatment (OR 4.3, CI 95% 1.3-16.6) as variables significantly associated with an increased risk of death. Major complications during follow-up (death, re-operation, or re-admission for HF) among the five operative survivors with residual fistulae occurred in 20 and 100% of patients at 1 and 2 years, respectively.

CONCLUSION

Aorto-cavitary fistulous tract formation is an uncommon but extremely serious complication of IE. In-hospital mortality was exceptionally high despite aggressive management with surgical intervention in the majority of patients. Prosthetic IE, urgent surgery, and the development of HF identify the subgroup of patients with IE and ACF that have significantly increased risk of in-hospital death.

Brucella Endocarditis: Clinical, Diagnostic, and Therapeutic Approach

Brucella endocarditis is an uncommon focal complication of brucellosis. Presented here are 11 cases of Brucella endocarditis, all managed uniformly. The median duration of symptoms prior to diagnosis was 3 months. Five patients (45%) had underlying valvular damage, and in six (55%) endocarditis involved a normal valve. There was a predominance of aortic involvement (82%) and a high incidence of left ventricular failure (91%). Diagnostic suspicion was essential in order to test blood cultures correctly, which in this series were positive in 63% of the patients. Surgical treatment was undertaken in eight patients (72%), all with aortic involvement and left ventricular failure impossible to control with medication. One patient died during the immediate postoperative period. All the other patients received antibiotic therapy for 3 months, with no signs of relapse of the infection or malfunction of the prosthesis during a minimum follow-up period of 24 months.

Computer simulation of jitter phenomenon in neuromuscular transmission disorders

Neuromuscular jitter is a sensitive measure of the safety factor of neuromuscular transmission. Nevertheless, the actual relationship between jitter and the safety factor is unknown because these parameters have not been simultaneously measured. In order to explore the theoretical relationship between them, a computer model of mammalian neuromuscular transmission has been developed. If the safety factor is expressed as the absolute value of the natural logarithm of the probability of a block, the model predicts a double exponential relationship between the safety factor and jitter, except when the percentage of blocks is greater than 90%. In that case, the jitter value decreases. Simulation of acetylcholinesterase inhibition shows that this treatment decreases the neuromuscular transmission blocks more effectively in postsynaptic than in presynaptic disorders. In contrast, when the percentage of blocks is greater than 60%, the jitter value increases in both conditions.

Diagnostic yield of a PCR assay in focal complications of brucellosis

In order to evaluate the diagnostic yield of a PCR assay for patients with focal complications of brucellosis, we studied by PCR and by conventional microbiological techniques 34 nonblood samples from 32 patients with different focal forms of brucellosis. The samples from patients with brucellosis were paired to an equal number of control samples from the same locations of patients whose illnesses had different etiologies. Thirty-three of the 34 nonblood samples (97%) from the brucellosis patients were positive by PCR, whereas Brucella spp. were isolated from only 29.4% of the conventional cultures. For 11.4% of the patients, the confirmatory serological tests were either negative or showed titers below the diagnostic range. Two patients (6.2%) from the control group, both with tuberculous vertebral osteomyelitis, had a positive PCR result. The brucella PCR of blood from these two patients was also positive, and the two strains of Mycobacterium tuberculosis isolated were analyzed by the brucella PCR, with no evidence of amplification. These results show that the PCR assay is far more sensitive than conventional cultures, and this, coupled with its speed and reduction in risk to laboratory workers, makes this technique a very useful tool for the diagnosis of focal complications of brucellosis.

Molecular characterization of Ct-hrp65: identification of two novel isoforms originated by alternative splicing

Hrp65, a protein with two conserved RNA-binding domains, has been identified in Chironomus tentans as a component of nuclear fibers associated with ribonucleoprotein particles in transit from the gene to the nuclear pore. We have cloned two novel hrp65 isoforms and characterized the structure of the hrp65 gene. Comparison of the hrp65 gene to the hrp65 cDNAs revealed that the multiple hrp65 isoforms, hrp65-1, hrp65-2 and hrp65-3, are generated by alternative splicing of a single pre-mRNA. The hrp65-3 mRNA is only detected in C. tentans tissue culture cells of embryonic origin, whereas hrp65-1 and hrp65-2 mRNAs appear to be constitutively expressed. The hrp65 mRNAs are generated by differential 3' splice site selection at the last exon of the gene. Thus, the three hrp65 transcripts contain different 3' UTRs and encode proteins that vary in their C-terminal ends. Interestingly, the variant C-terminal region determines the subcellular localization of the hrp65 proteins. In transient transfection assays, hrp65-1 is efficiently targetted to the nucleus, whereas hrp65-2 and hrp65-3 localize mainly to the cytoplasm. Moreover, hrp65-3 is associated with cytoplasmic actin fibers. All together, our findings suggest that the different hrp65 isoforms serve specialized roles related to mRNA localization/transport in the different cell compartments.

Early development of beta-cells is impaired in the GK rat model of type 2 diabetes

The Goto-Kakisaki (GK) rat is a genetic model of type 2 diabetes obtained by selective inbreeding of mildly glucose-intolerant Wistar rats. Previous studies have shown that at birth, the beta-cell mass of the GK rat is severely reduced compared with that of the Wistar rat. Therefore, beta-cell deficit could be the primary defect leading to type 2 diabetes in this model. To identify the abnormality at the origin of the beta-cell mass deficit, we compared the fetal development of GK and Wistar rats. Our study reveals that during early development (embryonic day 12-14 [E12-14]), GK fetuses present a delayed global growth that progressively recovers: at birth, no size or weight difference persists. However, from E18 onward, the weight and DNA content of the pancreas and liver are reduced by 30% in the GK fetuses. Cell proliferation is reduced in the GK pancreas from E16 to E20. Whereas apoptotic cells are scarce in the Wistar fetal pancreas, a wave of apoptosis from E16 to E18 was detected in the GK pancreas. Analysis of pancreas differentiation revealed that from E12 to E14, there are no significant differences in the number of alpha- and beta-cells between the GK and Wistar pancreas. However, by E16, the average number of beta-cells in the GK pancreas represents only 50% that of the Wistar pancreas, and this difference persists until birth. The number of alpha-cells was reduced by 25% from E18 to E21. To determine whether the defect in GK pancreas development depends on intrinsic pancreatic factors or on endocrine extrapancreatic factors, we performed in vitro cultures of E12 pancreatic rudiments. The cultures show that in vitro, the growth and endocrine differentiation of the GK and Wistar pancreatic rudiments are identical. Thus, impaired development of the GK pancreas probably results from insufficiency of extrapancreatic factor(s) necessary for the growth and survival of fetal pancreatic cells.