Systemic availability of guanidinoacetate affects GABAA receptor function and seizure threshold in GAMT deficient mice

Deficiency of guanidinoacetate methyltransferase (GAMT) causes creatine depletion and guanidinoacetate accumulation in brain with the latter deemed to be responsible for the severe seizure disorder seen in affected patients. We studied electrical brain activity and GABAA mediated mechanisms of B6J.Cg-Gamt(tm1Isb) mice. Electrocorticographic (ECoG) monitoring of pharmacological treatments with ornithine (5 % in drinking water for 5-18 days) and/or Picrotoxin (PTX) (a GABAA receptor antagonist) (1.5 mg/kg, I.P.) in Gamt(MUT) and Gamt(WT) groups [n = 3, mean age (SEM) = 6.9 (0.2) weeks]. Mice were fitted with two frontal and two parietal epidural electrodes under ketamine/xylazine anesthesia. Baseline and test recordings were performed for determination of seizure activity over a 2 h period. The ECoG baseline of Gamt(MUT) exhibited an abnormal monotonous cortical rhythm (7-8 Hz) with little variability during awake and sleep states compared to wild type recordings. Ornithine treatment and also PTX administration led to a relative normalization of the Gamt(MUT) ECoG phenotype. Gamt(WT) on PTX exhibited electro-behavioral seizures, whereas the Gamt(MUT) did not have PTX induced seizures at the same PTX dose. Gamt(MUT) treated with both ornithine and PTX did not show electro-behavioral seizures while ornithine elevated the PTX seizure threshold of Gamt(MUT) mice even further. These data demonstrate: (1) that there is expression of electrical seizure activity in this Gamt-deficient transgenic mouse strain, and (2) that the systemic availability of guanidinoacetate affects GABAA receptor function and seizure thresholds. These findings are directly and clinically relevant for patients with a creatine-deficiency syndrome due to genetic defects in GAMT and provide a rational basis for a combined ornithine/picrotoxin therapeutic intervention.

[Inborn errors of metabolism: transition from childhood to adulthood]

Inborn errors of metabolism (IEM) are due to mutations of genes coding for enzymes of intermediary metabolism and are classified into 3 broad categories: 1) intoxication, 2) energy defect and 3) cellular organelles synthesis or catabolism defect. Improvements of therapy over these last 20 years has improved prognosis of children with IEM. These children grow up and should have their transition to specialized adult care. Adult patients with IEM are a relatively new phenomenon with currently only limited knowledge. Extrapolated pediatric guidelines are applied to the adult population taking into account adult life stages (social independence, pregnancy, aging process and potential long-term complications).

Pure red cell aplasia associated with systemic lupus erythematosus

Pure red cell aplasia is a rare condition described in patients with autoimmune diseases such as systemic lupus erythematosus. Bone marrow examination of a 52-year-old female showed selective severe hypoplasia, scarce hematopoietic reserves, and no abnormality in other cell lineages, which are findings compatible with red cell aplasia. This condition has not responded to corticosteroids, cytotoxic drugs or intravenous immunoglobulin. After therapy with high doses of glucocorticoids, cyclophosphamide, and immunoglobulin failed, she was treated with human recombinant erythropoietin, monthly pulses of methylprednisolone, and cyclophosphamide, simultaneously. Data on treatment with erythropoietin for pure red cell aplasia associated with systemic lupus erythematosus is limited, but it appears to be reasonable to try in refractory cases.

Association of the ROBO1 gene with reading disabilities in a family-based analysis

Linkage studies have identified a locus on chromosome 3 as reading disabilities (RD) and speech and sound disorder (SSD) susceptibility region, with both RD and SSD sharing similar phonological processing and phonological memory difficulties. One gene in this region, roundabout homolog 1 (ROBO1), has been indicated as a RD candidate and has shown significant association with measures of phonological memory in a population-based sample. In this study, we conducted a family-based association analysis using two independent samples collected in Toronto and Calgary, Canada. Using the two samples, we tested for association between ROBO1 single nucleotide polymorphisms (SNPs) and RD, along with quantitative measures for reading, spelling and phonological memory. One SNP, rs331142, which was selected based on its correlation with ROBO1 expression in brain tissue, was found to be significantly associated with RD in the Toronto sample with over transmission of the minor C allele (P = 0.001), correlated with low expression. This SNP is located ~200 bp from a putative enhancer and results for a marker within the enhancer, rs12495133, showed evidence for association with the same allele in both the Toronto and Calgary samples (P = 0.005 and P = 0.007). These results support previous associations between ROBO1 and RD, as well as correlation with low gene expression, suggesting a possible mechanism of risk conferred by this gene.

In vitro and in vivo studies with tetra-hydro-jasmonic acid (LR2412) reveal its potential to correct signs of skin ageing

BACKGROUND

LR2412, a synthetic derivative of jasmonic acid, improved the reconstruction and homeostasis of our organotypic skin models.

OBJECTIVES

The need for efficient 'anti-ageing' treatments, in particular for the management of photoaged skin, prompted us to investigate this new ingredient for its potential to correct signs of skin ageing in vitro and in vivo and to identify its mode of action.

RESULTS

In vitro, penetration of LR2412 was evaluated using a Franz diffusion cell on excised human skin. Its exfoliating properties and interactions with the stratum corneum were studied using electron microscopy and X-ray diffraction. Experiments were performed on a human reconstructed skin model. In vivo, the effects of LR2412 on steroid-induced skin atrophy, a clinical skin ageing model, were assessed vs. vehicle. A patch test study evaluated its effect on deposition of fibrillin-rich microfibrils in the papillary dermis in clinically photoaged volunteers. A clinical study on the appearance of crow's feet wrinkles was conducted over 3 months of daily application. Penetration studies revealed that LR2412 reaches viable epidermis and superficial dermis, which are skin targets of anti-ageing actives. Within the upper layers of the stratum corneum LR2412 accelerates desquamation and improves the mechanical properties. At the dermal-epidermal junction of reconstructed skin, collagen IV, laminin-5 and fibrillin were stimulated. In vivo, LR2412 reversed steroid-induced atrophy. The patch test model confirms the deposition of fibrillin-rich microfibrils, then an in use clinical study revealed that it reduced facial wrinkles.

CONCLUSIONS

The in vitro and in vivo data demonstrate that based on its multiple interactions within human skin, LR2412 has potential to partially correct the signs of ageing in intrinsically and photoaged skin.

A family-based association analysis and meta-analysis of the reading disabilities candidate gene DYX1C1

Reading disabilities (RD) have a significant genetic basis and have shown linkage to multiple regions including chromosome 15q. Dyslexia susceptibility 1 candidate gene 1 (DYX1C1) on chromosome 15q21 was originally proposed as a candidate gene with two potentially functional polymorphisms at the -3G/A and 1249G/T positions showing association with RD. However, subsequent studies have yielded mixed results. We performed a literature review and meta-analysis of the -3G/A and 1249G/T polymorphisms, including new unpublished data from two family-based samples. Ten markers in DYX1C1 were genotyped in the two independently ascertained samples. Single marker and -3G/A:1249G/T haplotype analyses were performed for RD in both samples, and quantitative trait analyses using standardized reading-related measures was performed in one of the samples. For the meta-analysis, we used a random-effects model to summarize studies that tested for association between -3G/A or 1249G/T and RD. No significant association was found between the DYX1C1 SNPs and RD or any of the reading-related measures tested after correction for the number of tests performed. The previously reported risk haplotype (-3A:1249T) was not biased in transmission. A total of 9 and 10 study samples were included in the meta-analysis of the -3G/A and 1249G/T polymorphisms, respectively. Neither polymorphism reached statistical significance, but the heterogeneity for the 1249G/T polymorphism was high. The results of this study do not provide evidence for association between the putatively functional SNPs -3G/A and 1249G/T and RD.

Resequencing microarray method for molecular diagnosis of human arboviral diseases

BACKGROUND

Resequencing DNA microarray (RMA) technology uses probes designed to identify a panel of viral sequences. It can be used for detecting emerging viruses by revealing the nucleotide polymorphisms within the target of interest.

OBJECTIVES/STUDY DESIGN

As a new tool for molecular diagnosis of arbovirus infection, high density PathogenID v2.0 RMA (PID2-RMA) was assessed for the detection and genetic analysis of dengue, West Nile, and Chikungunya viruses in spiked blood samples or sera from individuals infected with dengue virus. Viral RNAs extracted from biological samples were retrotranscribed into cDNA and amplified using the Phi 29 polymerase-based method. This amplified cDNA was used for hybridization on PID2-RMA.

RESULTS

A good specificity of RMA-based detection was demonstrated using a panel of arboviruses including Dengue, West Nile and Chikungunya viruses. This technology was also efficient for the detection and genetic analysis of the different serotypes of dengue virus in sera of infected patients. Furthermore, the mixing of dengue, West Nile and Chikungunya prototype viruses within a single sample of human blood did not interfere with the sensitivity of PID2-RMA.

CONCLUSIONS

Our data show that high density PID2-RMA was suitable for the identification of medically important arboviruses. It appears to be particularly adapted to the genetic analysis of dengue, West Nile, and Chikungunya viruses in urgent clinical situations where the rapid identification and characterization of the pathogen is essential.

A three-year retrospective study of emergency visits at an oral health clinic in south-east Queensland

BACKGROUND

There is little information available regarding dental emergencies for children in Australia. The aim of this study was to investigate the reasons for dental emergency cases which were treated at a public oral health clinic in a low socioeconomic district in south-east Queensland.

METHODS

From a register kept at a public oral health clinic, we analysed the monthly number of emergency visits for children over a three-year period (January 2008 to August 2010) with respect to numbers treated, reasons for presentation and types of treatment rendered.

RESULTS

During the period 2008-2010, there was a mean of 196 ± 86 cases presenting for emergency care each month. The proportions of the various types of emergencies remained fairly consistent over the three-year period, with the majority presenting for caries related problems (74-75%), followed by trauma (8-9%), orthodontic treatment related (2-5%) and other reasons (16-11%). Between 8-11% of cases were preschool children who were added to the waitlist for treatment for caries under general anaesthesia at the public hospital.

CONCLUSIONS

Trends in the past three years at a public oral health clinic in a low socioeconomic district in south-east Queensland show that dental caries constitute nearly three-quarters of all paediatric emergency appointments.

Thalidomide and chemotherapy combination

Angiogenesis has been shown to be important in tumor growth and metastasis. Thalidomide, an oral sedative, has recently been found to inhibit angiogenesis. We therefore set out to ask whether thalidomide can be used as therapy for breast cancer. In a mouse model of breast cancer, we found that thalidomide alone did not suppress tumor growth. However, mice treated with thalidomide in combination with cytoxan and adriamycin had significantly smaller tumors than those given the two chemotherapeutic agents alone (3,432 +/- 303 mm(3) versus 4,643 +/- 203 mm(3), p = 0.0005). We proceeded to administer thalidomide together with chemotherapy to seven breast cancer patients in the context of a Phase I trial. Side effects attributed to thalidomide were minimal, and included constipation and a rash. We concluded that an approach at cancer therapeutics combining an antiangiogenic agent such as thalidomide with conventional chemotherapy may be feasible and deserves further studies.

[How to prevent severe hypoglycemia in older patients with type 2 diabetes]

Severe hypoglycemia is a feared complication of treatment in older diabetic patients (> 75 years) and a limiting factor for good glycemic control. Its real incidence is not well studied and probably underestimated. Cognitive impairment, malnutrition and/or cachexia, polypharmacy and a recent hospitalization are risk factors for severe hypoglycemia specific for older patients. Cognitive impairment screening can identify patients unable to manage their treatment. Simplification of treatment and/or transferring its execution to relatives must then be considered. Prevention also involves the detection of malnutrition and comorbidities, Age-adjusted therapeutic targets (HbA1c 7-8%) are important to avoid an exceedingly strict glycemic control. However, giving up on good glycemic control is not an adequate prevention strategy in itself.

[Management of gestational diabetes: current knowledge and future perspectives]

Gestational diabetes (GDM) is one of the most common complications of pregnancy and its prevalence is increasing continuously. Diagnosis, screening of GDM and therapeutic interventions are topics of ongoing controversies and uncertainty that have contributed to make the management of GDM complex and different from one country to another. Recent studies, such as ACHOIS and HAPO, have contributed to better define screening criteria and international recommendations and have demonstrated that management of GDM, including glucose monitoring, diet and insulin if needed, is worthwhile. This article summarizes the current status of screening, management of GDM and postpartum follow-up.

[Glycated hemoglobin: a new screening tool?]

Evaluation of mean glycemic control in diabetic patients is possible with the measure of glycosylated hemoglobin (HbA1c). Recently, new recommendations were made giving this test a diagnostic value for diabetes. HbA1c is the best prediction parameter of complications linked to diabetes; its measure is relatively accurate and simple. Nevertheless, the threshold value is arbitrary and a standardized method of dosage still remains limited. The aim of this article is to analyze the implementation of this dosage, its advantages and disadvantages as a diagnostic tool in comparison with plasma glycaemia, and current data concerning its sensibility, specificity and clinical implication.