Improvement of insulin sensitivity by a novel drug, BGP-15, in insulin-resistant patients: a proof of concept randomized double-blind clinical trial

The efficacy and safety of the new drug, BGP-15, were compared with placebo in insulin-resistant patients in a 28-day dose-ranging study. Forty-seven nondiabetic patients with impaired glucose tolerance were randomly assigned to 4 weeks of treatment with 200 or 400 mg of BGP-15 or placebo. Insulin resistance was determined by hyperinsulinemic euglycemic clamp technique and homeostasis model assessment method, and beta-cell function was measured by intravenous glucose tolerance test. Each BGP-15 dose significantly increased whole body insulin sensitivity (M-1, p=0.032), total body glucose utilization (M-2, p=0.035), muscle tissue glucose utilization (M-3, p=0.040), and fat-free body mass glucose utilization (M-4, p=0.038) compared to baseline and placebo. No adverse drug effects were observed during treatment. BGP-15 at 200 or 400 mg significantly improved insulin sensitivity in insulin-resistant, nondiabetic patients during treatment compared to placebo and was safe and well-tolerated. This was the first clinical study demonstrating the insulin-sensitizing effect of a molecule, which is considered as a co-inducer of heat shock proteins.

Fetoscopic laser treatment of twin-to-twintransfusion syndrome (TTTS)

The aim of this study was to report the results of the first 10 cases of fetoscopic laser surgery for twin-to-twin transfusion syndrome by the Rotunda Hospital Fetal Treatment Programme. All cases of severe TTTS managed by our team from 2006 to 2007 were included. All fetoscopic laser surgeries were performed by a single specialist in fetal medicine. All pregnancies were followed up to pregnancy completion and a minimum of six weeks neonatal life. Laser surgeries were performed with ultrasound guidance and percutaneously using local anaesthesia via a 2.8mm rigid fetoscope. Selective laser ablation of placental vessels was accomplished with a neodymium:YAG laser. The first 10 cases of severe TTTS managed by our team are reported. Laser ablation of placental vessels was accomplished successfully in all cases. Two pregnancies were complicated by preterm premature rupture of membranes before 22 weeks and both pregnancies were lost. Of the remaining 16 fetuses, one was diagnosed with significant ventriculomegaly postoperatively and underwent selective termination in the United Kingdom. The overall intact neonatal survival rate was 65%. Fetoscopic laser ablation of placental vessels for severe twin-to-twin transfusion syndrome is now available in Ireland, and our programme has delivered results that are in keeping with international best practices in this regard.

Metabolic aspects of organogenesis in the shoot apical meristem

Research over the last decade has led to tremendous advances in the characterization of the transcriptional networks involved in the initiation and maintenance of the shoot apical meristem (SAM), as well as the factors involved in the formation and development of leaves by this organ. However, one aspect of the SAM that has received rather limited attention is the fact that it is characterized by being heterotrophic, in contrast to the majority of cells and tissues immediately derived from it which rapidly undergo differentiation to form photosythetically active, autotrophic organs. This clear physiological and biochemical distinction of the SAM from the surrounding tissue raises interesting questions as to what controls the transition from heterotrophic to autotrophic growth, the nature and sequence of the metabolic events that must occur on this transition, as well as basic questions as to the potential interaction of development and metabolism in this small but essential organ of the plant. In this review, an overview is provided of present knowledge in this area, as well as some recent data that provide an insight into the potential intertwining of metabolic and developmental mechanisms during leaf initiation.

Monitoring patients in complete cytogenetic remission after treatment of CML in chronic phase with imatinib: patterns of residual leukaemia and prognostic factors for cytogenetic relapse

We monitored BCR-ABL transcript levels by quantitative real-time PCR in 103 patients treated with imatinib for chronic myeloid leukaemia in chronic phase for a median of 30.3 months (range 5.5-49.9) after they achieved complete cytogenetic remission (CCyR). The patients could be divided into three groups: (1) in 32 patients transcript levels continued to decline during the period of observation (nadir BCR-ABL/ABL ratio 0.015%); in five of these patients BCR-ABL transcripts became undetectable on repeated testing, (2) in 42 patients the transcript levels reached a plateau and (3) in 26 patients transcript numbers increased and the initial CCyR was lost. Three patients were not evaluable. Patients who remained in CCyR for at least 24 months appeared to have a low risk of subsequent cytogenetic relapse. We conclude that the pattern of 'residual' disease after achieving CCyR on imatinib is variable: some patients in CCyR show a progressive reduction in the level of residual disease, some reach a plateau where transcript numbers are relatively stable and others relapse with Ph-positive metaphases.

The endless quest for sex determination genes

Disorders in human sex determination cause defects in gonadal function and can result in a spectrum of abnormalities in the internal and external genitalia, ranging from relatively mild sexual ambiguities to complete sex reversal. Several genes involved in sex determination have been validated in humans, and activities of their gene products are being elucidated, particularly in mouse models. However, how these genes interact in an overall process remains far from clear, and it is probable that many additional genes are involved. Management of patients with pathologies in sex determination and subsequent differentiation is currently under debate, but will require not only an understanding of the multiple definitions of an individual's sex but also an increased knowledge of the molecular mechanisms involved in sex determination.

Role of steroidogenic factor 1 and aromatase in temperature-dependent sex determination in the red-eared slider turtle

Red-eared slider turtles are genetically bipotential for sex determination. In this species, as in many other reptiles, incubation temperature of the egg determines gonadal sex. At higher incubation temperatures females are produced and increasing temperature appears to increase estrogen production in the embryonic brain. Treatment of eggs incubating at a male-producing temperature with exogenous estrogen causes ovaries to form. At a female-biased incubation temperature, prevention of estrogen biosynthesis or administration of nonaromatizable androgens results in the development of testes. In mammals, steroidogenic factor 1 (SF-1) regulates most genes required for estrogen biosynthesis, including aromatase. In both mammals and red-eared sliders, SF-1 is differentially expressed in males and females during gonadogenesis. We have examined both SF-1 gene expression and aromatase activity in embryos incubating at different temperatures and after manipulation to change the course of gonadal development. Our findings indicate a central role for SF-1 in enacting the effect of estrogen. Estrogen treatment directly or indirectly downregulates SF-1 and, ultimately, causes development of females. The inhibition of estrogen results in upregulation of SF-1 and male hatchlings. Thus, SF-1 may lie at the center of one molecular crossroad in male versus female differentiation of the red-eared slider.

Local expression of expansin induces the entire process of leaf development and modifies leaf shape

Expansins are a family of extracellular proteins proposed to play a key role in wall stress relaxation and, thus, in cell and tissue growth. To test the possible function of expansins in morphogenesis, we have developed a technique that allows transient local microinduction of gene expression in transgenic plants. We have used this system to manipulate expansin gene expression in various tissues. Our results indicate that local expansin expression within the meristem induces a developmental program that recapitulates the entire process of leaf formation. Moreover, local transient induction of expansin expression on the flank of developing primordia leads to the induction of ectopic lamina tissue and thus modulation of leaf shape. These data describe an approach for the local manipulation of gene expression and indicate a role for expansin in the control of both leaf initiation and shape. These results are consistent with the action of cell division-independent mechanisms in plant morphogenesis.

Differential expression of XET-related genes in the leaf elongation zone of F. pratensis

Festuca pratensis Huds. is a forage grass with the ability to withstand harsh climatic conditions. However, its potential agronomic use is limited by its poor competitive ability, which can be traced to limitations in leaf growth. In order to characterize this process and to identify genes which might function as markers for leaf growth, three XET-related genes in the leaf elongation zone (LEZ) of F. pratensis are reported. A detailed expression analysis is presented of the three genes in two F. pratensis genotypes with contrasting leaf growth characteristics grown under two nitrogen levels. By means of a detailed spatial analysis of growth and XET encoding transcript pattern along the LEZ, a specific correlation is shown between FpXET1 expression and tissue elongation that is maintained under the different growth conditions, while the two other XETs expressed in the LEZ show different transcript dynamics. Tissue localization of FpXET1 and FpXET2 transcripts indicate an accumulation throughout young tissue, which is consistent with the encoded proteins playing roles in cell wall modification processes during growth. It is proposed that FpXET1 is a potential marker for tissue elongation and leaf growth in F. pratensis.

Differential expression of alpha- and beta-expansin genes in the elongating leaf of Festuca pratensis

Grasses contain a number of genes encoding both alpha- and beta-expansins. These cell wall proteins are predicted to play a role in cell wall modifications, particularly during tissue elongation. We report here on the characterisation of five alpha- and three vegetative beta-expansins expressed in the leaf elongation zone (LEZ) of the forage grass, Festuca pratensis Huds. The expression of the predominant alpha-expansin (FpExp2) was localised to the vascular tissue, as was the beta-expansin FpExpB3. Expression of another beta-expansin (FpExpB2) was not localised to vascular tissue but was highly expressed in roots and initiating tillers. This is the first description of vegetative beta-expansin gene expression at the organ and tissue level and also the first evidence of differential expression between members of this gene family. In addition, an analysis of both alpha- and beta-expansin expression along the LEZ revealed no correlation with growth rate distribution, whereas we were able to identify a novel xyloglucan endotransglycosylase (FpXET1) whose expression profile closely mimicked leaf growth rate. These data suggest that alpha- and beta-expansin activities in the grass leaf are associated with tissue differentiation, that expansins involved in leaf growth may represent more minor components of the spectrum of expansin genes expressed in this tissue, and that XETs may be useful markers for the analysis of grass leaf growth.

Estradiol and incubation temperature modulate regulation of steroidogenic factor 1 in the developing gonad of the red-eared slider turtle

Red-eared slider turtles are genetically bipotential for sex determination, with incubation temperature of the egg determining gonadal sex. At higher incubation temperatures, females are produced, possibly due to increased biosynthesis of estrogen. Exogenous estrogen causes the formation of ovaries, and prevention of estrogen biosynthesis results in the development of testes. In mammals, steroidogenic factor 1 (SF-1) regulates most genes required for estrogen biosynthesis from cholesterol. In mammals as well as red-eared slider turtles, SF-1 is differentially expressed in males and females during gonadogenesis. To examine a possible role for SF-1 in temperature-dependent sex determination, we assayed its expression in red-eared slider turtles after treatments that alter sex development during gonadogenesis of the wild-type organism. We examined gonadal SF-1 expression in embryos 1) incubating at three different temperatures, 2) after treating eggs with estrogen at a male-producing temperature, and 3) after inhibition of estrogen biosynthesis at a female-producing temperature. Our findings suggest that both temperature and estrogen lie upstream of SF-1 in a sex-determining regulatory hierarchy in red-eared slider turtles and that estrogen directly or indirectly modulates the regulation of SF-1 expression.

The role of the notochord in vertebral column formation

The backbone or vertebral column is the defining feature of vertebrates and is clearly metameric. Given that vertebrae arise from segmented paraxial mesoderm in the embryo, this metamerism is not surprising. Fate mapping studies in a variety of species have shown that ventromedial sclerotome cells of the differentiated somite contribute to the developing vertebrae and ribs. Nevertheless, extensive studies in amniote embryos have produced conflicting data on exactly how embryonic segments relate to those of the adult. To date, much attention has focused on the derivatives of the somites, while relatively little is known about the contribution of other tissues to the formation of the vertebral column. In particular, while it is clear that signals from the notochord induce and maintain proliferation of the sclerotome, and later promote chondrogenesis, the role of the notochord in vertebral segmentation has been largely overlooked. Here, we review the established role of the notochord in vertebral development, and suggest an additional role for the notochord in the segmental patterning of the vertebral column.

Prehospital intubation in patients with severe head injury

BACKGROUND

Prehospital intubation and airway control is routinely performed by paramedics in critically injured patients. Despite the advantages provided by this procedure, numerous potential risks exist when this is performed in the field. We reviewed the outcome of patients with severe head injury, to determine whether prehospital intubation is associated with an improved outcome.

METHODS

A retrospective review of registry data of patients admitted to an urban trauma center with severe head injury (field Glasgow Coma Scale score of < or =8 and head Abbreviated Injury Scale score of > or =3) was performed. Patients were stratified by methods of airway control performed by prehospital personnel: not intubated, intubated, or unsuccessful intubation. Mortality was determined for each group. To control for significant variables between these populations, matching and multivariate analysis were performed.

RESULTS

Patients requiring prehospital intubation or in whom intubation was attempted had an increased mortality (81% and 77%, respectively) when compared with nonintubated patients (43%). The mortality for patients who had prehospital intubation performed did not demonstrate an improved survival using matching. In fact, intubated patients had a significantly higher relative risk (RR) of mortality when compared with nonintubation (RR = 1.74,p < 0.001) and unsuccessful intubation patients (RR = 1.53, p = 0.008)

CONCLUSION

For patients with severe head injury, prehospital intubation did not demonstrate an improvement in survival. Further prospective randomized trials are necessary to confirm these results.

A genetic risk factor for mouse neural tube defects: defining the embryonic basis

Genetic polymorphisms are thought to play an important role in determining susceptibility to neural tube defects (NTDs), for example between different ethnic groups, but the embryonic manifestation of these polymorphic genetic influences is unclear. We have used a mouse model to test experimentally whether polymorphic variations in the pattern of cranial neural tube closure can influence susceptibility to NTDs. The site at which cranial neural tube closure begins (so-called closure 2) is polymorphic between inbred mice. Strains with a caudal location of closure 2 (e.g. DBA/2) are relatively resistant to NTDs, whereas strains with a rostrally positioned closure 2 (e.g. NZW) exhibit increased susceptibility to NTDs. We tested experimentally whether altering the position of closure 2 can affect susceptibility to cranial NTDs, by back- crossing the splotch ( Sp (2H) ) mutant gene onto the DBA/2 background. As a control, Sp (2H) was transferred onto the NZW background, which resembles splotch mice in its closure pattern. Approximately 80% of Sp (2H) homozygotes develop NTDs, both cranial (exencephaly) and spinal (spina bifida). After transfer to the DBA/2 background, the frequency of cranial NTDs was reduced significantly in Sp (2H) homozygotes, confirming a protective effect of caudal closure 2. In contrast, Sp (2H) homozygotes on the NZW background had a persistently high frequency of cranial NTDs. The frequency of spina bifida was not altered in either backcross, emphasizing the specificity of this genetic effect for cranial neurulation. These findings demonstrate that variation in the pattern of cranial neural tube closure is a genetically determined factor influencing susceptibility to cranial NTDs.

Developmental expression of steroidogenic factor 1 in a turtle with temperature-dependent sex determination

A variety of reptiles possess temperature-dependent sex determination (TSD) in which the incubation temperature of a developing egg determines the gonadal sex. Current evidence suggests that temperature signals may be transduced into steroid hormone signals with estrogens directing ovarian differentiation. Steroidogenic factor 1 (SF-1) is one component of interest because it regulates the expression of steroidogenic enzymes in mammals and is differentially expressed during development of testis and ovary. Northern blot analysis of SF-1 in developing tissues of the red-eared slider turtle (Trachemys scripta), a TSD species, detected a single primary SF-1 transcript of approximately 5.8 kb across all stages of development examined. Analysis by in situ hybridization indicated nearly equivalent SF-1 expression in early, bipotential gonads at male (26 degrees C)- and female (31 degrees C)-producing incubation temperatures. In subsequent stages, as gonadal sex first becomes histologically distinguishable during the temperature-sensitive period, SF-1 expression increased in gonads at a male-producing temperature and decreased at a female-producing temperature, suggesting a role for SF-1 in the sex differentiation pathway. SF-1 message was also found in adrenal and in the periventricular region of the preoptic area and diencephalon, but there was no apparent sex bias in these tissues at any stage examined. The overall developmental pattern of SF-1 mRNA expression in T. scripta appears to parallel that found in mammals, indicating possible homologous functions.