Mechanisms of cold sensitivity of paramyotonia congenita mutation R1448H and overlap syndrome mutation M1360V

Missense mutations of the human skeletal muscle voltage-gated Na⁺ channel (hSkM1) cause a variety of neuromuscular disorders. The mutation R1448H results in paramyotonia congenita and causes cold-induced myotonia with subsequent paralysis. The mutation M1360V causes an overlapping syndrome with both K⁺-induced muscle weakness and cold-induced myotonia. The molecular mechanisms of the temperature dependence of these disorders are not well understood. Therefore we investigated physiological parameters of these Na⁺ channel mutations at different temperatures. Channel proteins were recombinantly expressed in human embryonic kidney cells and studied electrophysiologically, using the whole-cell patch-clamp technique. We compared the wild-type (WT) channel with both mutants at different temperatures. Both mutations had slower inactivation and faster recovery from inactivation compared to WT channels. This effect was more pronounced at the R1448H mutation, leading to a larger depolarization of the cell membrane causing myotonia and paralysis. The voltage dependence of activation of R1448H was shifted to more negative membrane potentials at lower temperature but not at the M1360V mutation or in the WT. The window current by mutation R1448H was increased at lower temperatures. The results of this study may explain the stronger cold-induced clinical symptoms resulting from the R1448H mutation in contrast to the M1360V mutation.     

Prevalence of Helicobacter pylori vacuolating cytotoxin and its allelic mosaicism as a predictive marker for Iranian dyspeptic patients

Helicobacter pylori infects the majority of the population in the developing countries. However, the rate of gastrointestinal complications such as peptic ulcers and gastric malignancies has no parallel with the infection. In order to determine whether cytotoxin (vacA) and its allelic polymorphism can serve as screening markers for such a population, H. pylori strains were isolated from one hundred and thirty two dyspeptic patients. H. pylori genomic DNA was extracted and underwent PCR-amplification for the cytotoxin alleles. Genotyping of the signal sequence region of the vacA gene identified 68% (70 out of 103) of patients with non ulcer dyspepsia (NUD) and 79% (23 out of 29) of the patients with peptic ulcer disease (PUD) possessing the s1 genotype. S1 strains were significantly more prevalent among patients with PUD as compared to the NUD (p < 0.05). In regard to the middle region, 55% of the patient isolates belonged to the m2 genotype with no correlation to disease. The s1m2 genotype was the most prevalent among all patients and significantly correlated with the PUD group (p < 0.05).     

Propylene Polymerization with rac‐SiMe2(2‐Me‐4‐PhInd)2ZrMe2/MAO: Polymer Characterization and Kinetic Models

Poly(propylene)s were prepared with metallocene catalyst rac‐SiMe₂(2‐Me‐4‐PhInd)₂ZrMe₂/MAO (rac‐dimethylsilylbis(2‐methyl‐4‐phenylindenyl)dimethylzirconium/methylaluminoxane) in heptane solution at temperatures from 50 to 80 °C with varying concentrations of monomer, hydrogen, triisobutylaluminium (TIBA) and MAO. Polymer molar mass depended on the monomer, MAO, TIBA, and hydrogen concentrations and on polymerization temperature. The isotacticity was very high (mmmm > 95%), and only a slight decrease was detected at high temperatures. Regio selectivity was also high; the total amount of 2,1‐ and 3,1‐insertions was less than 0.4 mol‐%. Lowering the monomer concentration and raising the temperature increased the amount of 3,1 defects over the amount of 2,1 defects. End‐group analysis by ¹³C NMR spectroscopy revealed isobutyl and allyl end‐groups. Chain transfer to aluminium and β‐CH₃ elimination were concluded to be the dominating chain‐termination mechanisms. The importance of β‐CH₃ elimination increased with temperature. Hydrogen addition changed both the initiation and termination mechanisms as indicated by the presence of propyl, butyl and 2,3‐dimethylbutyl end‐groups. According to modeling studies, the molar mass follows a first‐order relationship with propylene and hydrogen concentrations, and a half‐order relationship with MAO concentration. Arrhenius‐type activation energy coefficients were 125 kJ · mol^?1 for β‐CH₃ elimination, 66 kJ · mol^?1 for chain transfer to aluminium, and 53 kJ · mol^?1 for chain transfer to hydrogen. A value of 45 kJ · mol^?1 was used for the propagation.

     

Somatic FGF9 mutations in colorectal and endometrial carcinomas associated with membranous beta-catenin

We previously described striking molecular features including high frequency of membranous beta-catenin in subsets of familial colon cancers with as yet unknown predisposition. We hypothesized that such tumors might carry mutations in Wnt/beta-catenin target genes. Fibroblast growth factor 9 (FGF9) was an attractive target, as it maps to a common area of loss of heterozygosity (LOH) in colorectal carcinomas on 13q12.11. Here, we report, for the first time, the occurrence of FGF9 mutations in human cancers. We found a total of six distinct FGF9 mutations including one frameshift, four missense, and one nonsense, in 10 (six colorectal and four endometrial) out of 203 tumors and cell lines. The frameshift mutation was detected in five different tumors. Mapping of these mutations onto the crystal structure of FGF9 predicted that they should all lead to loss of function albeit through variable mechanisms. The p.R173K mutation should diminish ligand affinity for heparin/heparan sulfate, the p.V192M, p.D203G, and p.L188YfsX18 (FGF9(Delta205-208)) mutations should negatively impact ligand's interaction with receptor, while p.G84E and p.E142X (FGF9(Delta142-208)) mutations should interfere with ligand folding. Consistent with these structural predictions, the p.V192M, p.D203G, and p.L188YfsX18 (FGF9(Delta205-208)) mutations impaired the ability of ligand to activate mitogen-activated protein kinase (MAPK) cascade in cultured cells expressing FGF receptors. LOH was observed in seven out of nine FGF9 mutant tumors, supporting the predicted loss of function. Interestingly, eight out of 10 (80%) of the FGF9 mutant tumors showed normal membranous beta-catenin expression and the absence of mutation in the beta-catenin gene (CTNNB1). These data suggest that FGF9 plays a role in colorectal and endometrial carcinogenesis.     

Structural basis by which alternative splicing modulates the organizer activity of FGF8 in the brain

Two of the four human FGF8 splice isoforms, FGF8a and FGF8b, are expressed in the mid-hindbrain region during development. Although the only difference between these isoforms is the presence of an additional 11 amino acids at the N terminus of FGF8b, these isoforms possess remarkably different abilities to pattern the midbrain and anterior hindbrain. To reveal the structural basis by which alternative splicing modulates the organizing activity of FGF8, we solved the crystal structure of FGF8b in complex with the "c" splice isoform of FGF receptor 2 (FGFR2c). Using surface plasmon resonance (SPR), we also characterized the receptor-binding specificity of FGF8a and FGF8b, the "b" isoform of FGF17 (FGF17b), and FGF18. The FGF8b-FGFR2c structure shows that alternative splicing permits a single additional contact between phenylalanine 32 (F32) of FGF8b and a hydrophobic groove within Ig domain 3 of the receptor that is also present in FGFR1c, FGFR3c, and FGFR4. Consistent with the structure, mutation of F32 to alanine reduces the affinity of FGF8b toward all these receptors to levels characteristic of FGF8a. More importantly, analysis of the mid-hindbrain patterning ability of the FGF8b(F32A) mutant in chick embryos and murine midbrain explants shows that this mutation functionally converts FGF8b to FGF8a. Moreover, our data suggest that the intermediate receptor-binding affinities of FGF17b and FGF18, relative to FGF8a and FGF8b, also account for the distinct patterning abilities of these two ligands. We also show that the mode of FGF8 receptor-binding specificity is distinct from that of other FGFs and provide the first biochemical evidence for a physiological FGF8b-FGFR1c interaction during mid-hindbrain development. Consistent with the indispensable role of FGF8 in embryonic development, we show that the FGF8 mode of receptor binding appeared as early as in nematodes and has been preserved throughout evolution.     

Occurrence of parent-reported food hypersensitivities and food allergies among children aged 1–4 yr

Food allergies (FAs) and hypersensitivities (FHSs) have rarely been studied in large unselected child populations. This population-based cross-sectional survey estimated the occurrence of FHS as perceived by parents and that of FA diagnosed by a physician among children aged 1–4 yr in south-eastern Finland. Before the scheduled annual follow-up visit to the local child health clinic, the parents of children who were born between 1 April, 2001 and 31 March, 2005, and living in the Province of South Karelia (data from Finnish Population Register) were mailed a questionnaire containing items on the child's background, physician-diagnosed FAs and FHSs perceived by the parents. The questionnaires were returned during the visit. Three thousand three hundred and eight (69%) out of the 4779 questionnaires were returned. The lifetime prevalence of physician-diagnosed FAs was 9%. In an additional 21%, FHSs were perceived by the parents only. In a further 19% at least one food item had been eliminated from the diet without any perception of symptoms, this proportion having a downward trend by age. Physician-diagnosed FAs were more common in boys than in girls. Cow's milk was the most commonly reported cause of food-associated symptoms (13% of all children). One-third of the children aged 1–4 yr suffered from food-associated symptoms, and in an additional fifth at least one food item had been eliminated from their diet, implying that every other child had possibly been subjected to some form of elimination diet.     

Weakening of one more alcohol control pillar: a review of the effects of the alcohol tax cuts in Finland in 2004

Aims   To review the consequences of the changes in Finnish alcohol policy in 2004, when quotas for travellers' tax-free imports of alcoholic beverages from other European Union (EU) countries were abolished, Estonia joined the EU and excise duties on alcoholic beverages were reduced in Finland by one-third, on average.
Design   A review of published research and routinely available data.
Setting   Finland.
Measurements   Prices of alcoholic beverages, recorded and unrecorded alcohol consumption, data on criminality and other police statistics, alcohol-related deaths and hospitalizations, service use.
Findings   Alcohol consumption increased 10% in 2004, clearly more than in the early 2000s. With few exceptions, alcohol-related harms increased. Alcohol-induced liver disease deaths increased the most, by 46% in 2004–06 compared to 2001–03, which indicates a strong effect on pre-2004 heavy drinkers. Consumption and harms increased most among middle-aged and older segments of the population, and harms in the worst-off parts of the population in particular.
Conclusions   Alcohol taxation and alcohol prices affect consumption and related harms, and heavy drinkers are responsive to price. In Finland in 2004, the worst-off parts of the population paid the highest price in terms of health for cuts in alcohol prices. The removal of travellers' import quotas, which was an inherent part of creating the single European market, had serious public health consequences in Finland.     

Langerhans Cell Histiocytosis of the Lung and Thyroid, Co-Existing with Papillary Thyroid Cancer

A 24-year-old man presented to our center with a huge goiter compressing his airway. He had a previous diagnosis of Langerhans cell histiocytosis (LCH) of the lung. Core needle biopsy was consistent with histiocytosis. Thyroidectomy was performed. A very invasive mass was encountered at the time of surgery. Histopathology result was consistent with an invasive papillary cancer of thyroid co-occurring with LCH. Although association of LCH with different malignancies has been reported, co-existing invasive papillary thyroid cancer and LCH is a rare combination.     

Healing of subcapital femoral osteotomies fixed with self-reinforced poly-L-lactide screws: an experimental long-term study in sheep

Subcapital femoral osteotomies of ten young adult sheep were fixed with two bioabsorbable, self-reinforced, poly- L-lactide (SR-PLLA) lag screws of 4.5 mm in diameter. At 3 weeks radiographs were taken to check the reduction and fixation achieved. After follow-up periods of 12 weeks, 1 year and 3 years with three sheep in each group, and of 7 years and 4 months with one sheep, the sheep were killed, and the healing of the osteotomies, degradation and tissue response of the implants were examined radiographically, histologically and microradiographically. All osteotomies healed with a firm bony union. There was no dislocation or wound infection. Histologically, there was no marked tissue response in the bone tissue. At 12 weeks the implants were grossly intact, at 1 year granulation tissue and new bone formation had started to penetrate into the implant, and at 3 years the implant area was mostly replaced by connective tissue and new bone, but implant material was still seen as little islands surrounded by some lymphocytes. At 7 years and 4 months, the implant material had been degraded and replaced by tight bone. Self-reinforced poly- L-lactide lag screws seem to possess adequate mechanical properties and good biocompatibility for this demanding fixation.     

Intermediate follow-up of a composite stentless porcine valved conduit of bovine pericardium in the pulmonary circulation

BACKGROUND: In the pediatric population, glutaraldehyde-preserved bovine pericardium conduit containing a stentless porcine valve has been proposed as an alternative to homografts for right ventricular outflow tract reconstruction. METHODS: Between June 1996 and March 2000, a total of 55 patients, 20 with truncus arteriosus, 21 with pulmonary atresia with ventricular septal defect, and 14 with miscellaneous defects, received this conduit. Median age at implantation was 3.4 months (range, 3 days to 19 years), and 27 patients (50%) were less than 3 months old. Clinical outcome, echocardiographic data, and pathologic analysis were recorded. End points for conduit failure were conduit replacement or dilation. A mean follow-up of 27 months (range, 2 to 46 months) was available for 47 survivors. RESULTS: Procedure for conduit obstruction was required in 13 patients. The most common procedure was operation, and all but 3 patients had an unsuccessful balloon angioplasty before reoperation. Actuarial freedom from conduit dilation or reoperation was 93.6% (95% confidence limits, 82% to 99%), 81.9% (95% confidence limits, 64% to 91%), 77.8% (95% confidence limits, 39% to 78%), and 64.3% (95% confidence limits, 26% to 73%) at 1, 2, 3, and 4 postoperative years, respectively. Univariate analysis identified small conduit size as a risk factor for conduit obstruction. CONCLUSIONS: Although this new conduit was not free from progressive obstruction, our clinical results (easy to work and good valvular function) and the availability in small sizes encouraged us to use it as an alternative to small-size homografts when those were not available.