Clinical spectrum of BICD2 mutations.

BACKGROUND AND PURPOSE: Mutations in the BICD2 gene cause autosomal dominant lower extremity-predominant spinal muscular atrophy 2A (SMALED2A), a condition that is associated with a specific pattern of thigh and calf muscle involvement when studied by magnetic resonance imaging (MRI). Patients may present minor clinical sensory impairment, but objective sensory involvement has yet to be demonstrated. METHODS: We collected clinical data from 11 patients from five different families carrying mutations in BICD2. Genetic diagnosis was achieved using gene panel testing and skin biopsies were taken from two patients to study the epidermal nerve fiber density. RESULTS: In the studied patients, three new pathogenic mutations were detected as well as the already defined pathogenic p.Ser107Leu mutation. The most frequent clinical picture was characterized by lower-limb weakness in combination with foot deformities. One patient manifested clinical and electrophysiological sensory impairment, and the epidermal nerve fiber density study of another patient revealed the existence of a small-fiber neuropathy. Muscle MRI showed a common pattern of fat deposition including selective involvement of gluteus medius and minimus at the pelvic level, the anterior compartment of the thigh and the posterior compartment of the calf, with only mild or no involvement of the intrinsic foot muscles. CONCLUSIONS: We report three new pathogenic mutations in the BICD2 gene. Muscle MRI confirms the existence of a selective pattern of thigh and leg muscle involvement in SMALED2A, providing additional information regarding pelvic and foot muscles. Moreover, our results raise the possibility of sensory involvement in the disease.

Introgression of leaf rust and stripe rust resistance from Sharon goatgrass (Aegilops sharonensis Eig) into bread wheat (Triticum aestivum L.).

Leaf rust and stripe rust are devastating wheat diseases, causing significant yield losses in many regions of the world. The use of resistant varieties is the most efficient way to protect wheat crops from these diseases. Sharon goatgrass (Aegilops sharonensis or AES), which is a diploid wild relative of wheat, exhibits a high frequency of leaf and stripe rust resistance. We used the resistant AES accession TH548 and induced homoeologous recombination by the ph1b allele to obtain resistant wheat recombinant lines carrying AES chromosome segments in the genetic background of the spring wheat cultivar Galil. The gametocidal effect from AES was overcome by using an "anti-gametocidal" wheat mutant. These recombinant lines were found resistant to highly virulent races of the leaf and stripe rust pathogens in Israel and the United States. Molecular DArT analysis of the different recombinant lines revealed different lengths of AES segments on wheat chromosome 6B, which indicates the location of both resistance genes.

Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells.

The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40-100 nm and less than 44 microm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 microm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 microM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases.

Genome size in natural and synthetic autopolyploids and in a natural segmental allopolyploid of several Triticeae species.

Nuclear DNA amount (1C) was determined by flow cytometry in the autotetraploid cytotype of Hordeum bulbosum, in the cytologically diploidized autotetraploid cytotypes of Elymus elongatus, Hordeum murinum subsp. murinum and Hordeum murinum subsp. leporinum, in Hordeum marinum subsp. gussoneanum, in their progenitor diploid cytotypes, and in a newly synthesized autotetraploid line of E. elongatus. Several lines collected from different regions of the distribution area of every taxon, each represented by a number of plants, were analyzed in each taxon. The intracytotype variation in nuclear DNA amount of every diploid and autotetraploid cytotype was very small, indicating that no significant changes have occurred in DNA amount either after speciation or after autopolyploid formation. The autotetraploid cytotypes of H. bulbosum and the cytologically diploidized H. marinum subsp. gussoneanum had the expected additive amount of their diploid cytotypes. On the other hand, the cytologically diploidized autotetraploid cytotypes of E. elongatus and H. murinum subsp. murinum and H. murinum subsp. leporinum had considerably less nuclear DNA (10%-23%) than the expected additive value. Also, the newly synthesized autotetraploid line of E. elongatus showed similar reduction in DNA as its natural counterpart, indicating that the reduction in genome size occurred in the natural cytotype during autopolyploidization. It is suggested that the diploid-like meiotic behavior of these cytologically dipolidized autotetraploids is caused by the instantaneous elimination of a large number of DNA sequences, different sequences from different homologous pairs, leading to differentiation of the constituent genomes. The eliminated sequences are likely to include those that participate in homologous recognition and initiation of meiotic pairing. A gene system determining exclusive bivalent pairing by utilizing the differentiation between the two groups of homologues has been presumably superimposed on the DNA reduction process.

Genetics of resistance to wheat leaf rust, stem rust, and powdery mildew in Aegilops sharonensis.

Aegilops sharonensis (Sharon goatgrass) is a wild relative of wheat and a rich source of genetic diversity for disease resistance. The objectives of this study were to determine the genetic basis of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis and also the allelic relationships between genes controlling resistance to each disease. Progeny from crosses between resistant and susceptible accessions were evaluated for their disease reaction at the seedling and/or adult plant stage to determine the number and action of genes conferring resistance. Two different genes conferring resistance to leaf rust races THBJ and BBBB were identified in accessions 1644 and 603. For stem rust, the same single gene was found to confer resistance to race TTTT in accessions 1644 and 2229. Resistance to stem rust race TPMK was conferred by two genes in accessions 1644 and 603. A contingency test revealed no association between genes conferring resistance to leaf rust race THBJ and stem rust race TTTT or between genes conferring resistance to stem rust race TTTT and powdery mildew isolate UM06-01, indicating that the respective resistance genes are not linked. Three accessions (1644, 2229, and 1193) were found to carry a single gene for resistance to powdery mildew. Allelism tests revealed that the resistance gene in accession 1644 is different from the respective single genes present in either 2229 or 1193. The simple inheritance of leaf rust, stem rust, and powdery mildew resistance in A. sharonensis should simplify the transfer of resistance to wheat in wide crosses.

Nuclear DNA amount and genome downsizing in natural and synthetic allopolyploids of the genera Aegilops and Triticum.

Recent molecular studies in the genera Aegilops and Triticum showed that allopolyploidization (interspecific or intergeneric hybridization followed by chromosome doubling) generated rapid elimination of low-copy or high-copy, non-coding and coding DNA sequences. The aims of this work were to determine the amount of nuclear DNA in allopolyploid species of the group and to see to what extent elimination of DNA sequences affected genome size. Nuclear DNA amount was determined by the flow cytometry method in 27 natural allopolyploid species (most of which were represented by several lines and each line by several plants) as well as 14 newly synthesized allopolyploids (each represented by several plants) and their parental plants. Very small intraspecific variation in DNA amount was found between lines of allopolyploid species collected from different habitats or between wild and domesticated forms of allopolyploid wheat. In contrast to the constancy in nuclear DNA amount at the intraspecific level, there are significant differences in genome size between the various allopolyploid species, at both the tetraploid and hexaploid levels. In most allopolyploids nuclear DNA amount was significantly less than the sum of DNA amounts of the parental species. Newly synthesized allopolyploids exhibited a similar decrease in nuclear DNA amount in the first generation, indicating that genome downsizing occurs during and (or) immediately after the formation of the allopolyploids and that there are no further changes in genome size during the life of the allopolyploids. Phylogenetic considerations of the origin of the B genome of allopolyploid wheat, based on nuclear DNA amount, are discussed.

Genome size and genome evolution in diploid Triticeae species.

One of the intriguing issues concerning the dynamics of plant genomes is the occurrence of intraspecific variation in nuclear DNA amount. The aim of this work was to assess the ranges of intraspecific, interspecific, and intergeneric variation in nuclear DNA content of diploid species of the tribe Triticeae (Poaceae) and to examine the relation between life form or habitat and genome size. Altogether, 438 plants representing 272 lines that belong to 22 species were analyzed. Nuclear DNA content was estimated by flow cytometry. Very small intraspecific variation in DNA amount was found between lines of Triticeae diploid species collected from different habitats or between different morphs. In contrast to the constancy in nuclear DNA amount at the intraspecific level, there are significant differences in genome size between the various diploid species. Within the genus Aegilops, the 1C DNA amount ranged from 4.84 pg in A. caudata to 7.52 pg in A. sharonensis; among genera, the 1C DNA amount ranged from 4.18 pg in Heteranthelium piliferum to 9.45 pg in Secale montanum. No evidence was found for a smaller genome size in annual, self-pollinating species relative to perennial, cross-pollinating ones. Diploids that grow in the southern part of the group's distribution have larger genomes than those growing in other parts of the distribution. The contrast between the low variation at the intraspecific level and the high variation at the interspecific one suggests that changes in genome size originated in close temporal proximity to the speciation event, i.e., before, during, or immediately after it. The possible effects of sudden changes in genome size on speciation processes are discussed.

Spatio-temporal genetic variation in populations of wild emmer wheat, Triticum turgidum ssp. dicoccoides, as revealed by AFLP analysis.

Genetic structure of natural populations of wild crop relatives has been the subject of many studies. Yet, most of them focused on the assessment of spatial genetic diversity, while information on long-term variation, affected by yearly changes, has been considered only in few cases. The present study aimed therefore, to estimate the spatio-temporal genetic variation in populations of wild emmer wheat, the progenitor of domesticated wheat, and to assess the contribution of spatial versus temporal factors to the maintenance of genetic variation in a population. Single spikes were collected in the years 1988 and 2002 from plants that grew in the same sampling points, from six different habitats in the Ammiad conservation site, Eastern Galilee, Israel. Seeds were planted in a nursery and DNA was extracted from each plant and analyzed by the AFLP method. Fourteen primer combinations yielded 1,545 bands of which 50.0 and 48.8% were polymorphic in the years 1988 and 2002, respectively. Genetic diversity was much larger within populations than between populations and the temporal genetic diversity was considerably smaller than the spatial one. Nevertheless, population genetic structure may vary to some degree in different years, mainly due to fluctuations in population size because of yearly rainfall variations. This may lead to predominance of different genotypes in different years. Clustering the plants by their genetic distances grouped them according to their habitats, indicating the existence of genotype-environment affinities. The significance of the results in relation to factors affecting the maintenance of polymorphism in natural populations is discussed.

Linearity and time-scale invariance of the creep function in living cells.

We report here the creep function measured in three cell types, after a variety of interventions, and over three time decades (from 3 ms to 3.2 s). In each case the response conformed to a power law, implying that no distinct molecular relaxation times or time constants could characterize the response. These results add to a growing body of evidence that stands in contrast to widely used viscoelastic models featuring at most a few time constants. We show instead that the ability of the matrix to deform is time-scale invariant and characterized by only one parameter: the power law exponent that controls the transition between solid-like and liquid-like behaviour. Moreover, we validate linearity by comparison of measurements in the time and frequency domains.

RFLP-based analysis of three RbcS subfamilies in diploid and polyploid species of wheat.

The RbcS multigene family of hexaploid (bread) wheat, Triticum aestivum (genome BBAADD), which encodes the small subunit of Rubisco, comprises at least 22 genes. Based on their 3' non-coding sequences, these genes have been classified into four subfamilies (SFs), of which three (SF-2, SF-3 and SF-4) are located on chromosomes of homoeologous group 2 and one (SF-1) on homoeologous group 5. In the present study we hybridized three RbcS subfamily-specific probes (for SF-1, SF-2 and SF-3) to total DNA digested with four restriction enzymes and analyzed the RFLP patterns of these subfamilies in eight diploid species of Aegilops and Triticum, and in two tetraploid and one hexaploid species of wheat (the diploid species are the putative progenitors of the polyploid wheats). The three subfamilies varied in their level of polymorphism, with SF-2 being the most polymorphic in all species. In the diploids, the order of polymorphism was SF-2 > SF-3 > SF-1, and in the polyploids SF-2 > SF-1 > SF-3. The RbcS genes of the conserved SF-1 were previously reported to have the highest expression levels in all the wheat tissues studied, indicating a negative correlation between polymorphism and gene expression. Among the diploids, the species with the D and the S genomes were the most polymorphic and the A-genome species were the least polymorphic. The polyploids were less polymorphic than the diploids. Within the polyploids, the A genome was somewhat more polymorphic than the B genome, while the D genome was the most conserved. Among the diploid species with the A genome, the RFLP pattern of T. urartu was closer to that of the A genome of the common wheat cultivar Chinese Spring (CS) than to that of T. monococcum. The pattern in Ae. tauschii was similar to that of the D genome of CS. Only partial resemblance was found between the RFLP patterns of the species with the S genome and the B genome of CS.

[Familial periodic ataxia with myokymia sensitive to acetazolamide: a family case]. / Ataxia periódica familiar con mioquimia sensible a acetazolamida: presentación de una familia.

INTRODUCTION: Acetazolamide responsive hereditary paroxysmal cerebellar ataxia with myokymia is a type of autosomal dominant cerebellar ataxia which locus was found to be linked to the short arm of chromosome 12 and the etiology is unknown. CLINICAL CASE: A 12 years-old man who suffered from childhood daily episodes of sudden attacks sport induced with giddiness, ataxia and dysarthria for minutes. The familial history shows the same clinical findings in three generations. Intercritical general neurologic evaluation is otherwise normal. The following tests were performed with normal results: Biochemistry, electroencephalogram, cerebral magnetic resonance imaging. The electromyography showed myokymic discharges. The patient's symptoms improve on treatment with acetazolamide immediately. CONCLUSIONS: Acetazolamide responsive hereditary paroxysmal cerebellar ataxia with myokymia needs to think on it to be diagnosed. No typical complementary test (electromyography exception) induces to base diagnosis in the clinical findings, the familial history and the fast clinical improvement after starting treatment with acetazolamide.

Intrathecal chemotherapy-related myeloencephalopathy in a young child with acute lymphoblastic leukemia.

Since the mid-1960s intrathecal chemotherapy (methotrexate [MTX], cytarabine [Ara-C], or both, plus hydrocortisone) has constituted the standard approach to prophylaxis and treatment of central nervous system (CNS) leukemia and lymphoma. Intrathecal chemotherapy-related neurotoxicity has been described in a variable proportion of patients. At least 35 cases of subacute myeloencephalopathy with transient or permanent paraplegia/quadriplegia after intrathecal chemotherapy have been reported. Different factors have been cited: high cumulative MTX dose, meningeal leukemia, cranial irradiation, and preservatives in MTX and Ara-C. A direct toxic effect of the intrathecal chemotherapy seems the most likely mechanism. Early imaging studies are usually normal. We describe a nonfatal case of permanent flaccid quadriplegia after the fourth triple intrathecal chemotherapy in a 6-year-old girl with acute lymphoblastic leukemia and no evidence of meningeal involvement. Six months after intrathecal chemotherapy, CNS magnetic resonance imaging showed severe atrophy of spine, cerebellum, and cerebral hemispheres. The outcome of reported cases is diverse. No treatment has been shown to reverse neurotoxicity. Among the cases reported in the literature, complete recovery of neurologic deficits was observed in 9 patients, partial recovery with variable sequelae in 6, no recovery in 8, and 13 patients died from the initial oncologic disease or neurotoxicity progression.

[Diltiazem poisoning: hemodynamic aspects]. / Intoxication médicamenteuse par diltiazem: aspects hémodynamiques.

A case is reported of a 50-year-old man who took a massive overdose of diltiazem (5,400 mg), together with 1,350 mg potassium clorazepate and 390 mg nordazepate, five months after having experienced a myocardial infarction (MI). On admission, systolic blood pressure was 80 mmHg, with an irregular heart rate of 60 b.min-1. There was superficial polypnea (40 c.min-1) with hypoxia (PaO2: 63.5 mmHg). The ECG revealed, besides the MI scar, complete sinus arrest. Endotracheal intubation and mechanical ventilation were rapidly required. The patient then had gastric lavage, and was given activated charcoal. Treatment with 1.5 mg atropine and 2 g intravenous calcium chloride were unable to amend the cardiac dysrhythmia. A continuous isoproterenol infusion restored a sinus rhythm, but this was not maintained because of the risk of side-effects. Cardiovascular collapse was treated with dobutamine (10 micrograms.kg-1.min-1). As the peripheral and pulmonary vascular resistances were greatly diminished (464 dyn.s.cm-5 and 86 dyn.s.cm-5 respectively), alpha and beta mimetics were used: 1 microgram.kg-1.min-1 noradrenaline and 15 micrograms.kg-1.min-1 dobutamine. After 7 h of this treatment, spontaneous sinus rhythm returned abruptly. Noradrenaline and dobutamine were replaced thereafter with adrenaline (0.25 microgram.kg-1.min-1), which was stopped 24 h later. There was a marked respiratory and haemodynamic improvement, the patient leaving the intensive care unit on the fourth day and returning home one week after the overdose. The relationships between cellular calcium movements and the adrenergic system are discussed, as well as the possible mechanism of cardiac failure.

Long-term in vitro culture of wheat grains.

Wheat (Triticum aestivum, Triticum durum) grains were excised immediately following fertilization and cultured until maturity. A rachis fragment attached to the grain was required to ensure an increase in grain size for the first 10 days following fertilization. A (14)C-labeling study revealed that 8-day-old grains accumulated more dry matter into the ethanol-insoluble fraction when grown on agar rather than when immersed in liquid medium. Light enhanced the absorption of sucrose from the medium only in the latter case. In agar-based culture, when no contact was made between the grain surface and the medium, peeling off the outer pericarp layers increased sugar absorption, leading to a threefold increase in the amount of accumulated dry matter in the ethanol-insoluble fraction. Culturing of wheat grains with attached rachis fragment and peeled pericarp is recommended for maximum in vitro growth.

Determination of right ventricular ejection fraction in children with cystic fibrosis.

The radionuclide right ventricular ejection fraction (RVEF) determined by means of Krypton-81m represents a simple, noninvasive, and accurate procedure to quantify the right ventricular contractility. This procedure was applied to 25 young patients with cystic fibrosis. The RVEF tended to decrease with the progression of the lung disease, as assessed by the clinical S-K score, the degree of the defects on lung scintigraphy, the PaO2, and the lung function tests. However, the decrease of RVEF in patients with marked lung function tests. However, the decrease of RVEF in patients with marked lung involvement was moderate, and terminal lung disease was sometimes associated with normal right heart contractility.

Monosomic analysis of heading date and spikelet number in the common wheat (Triticum aestivum L.) multispikelet line 'Noa'.

Genetic analysis of heading date and spikelet number was carried out in the common wheat (Triticum aestivum L.) multispikelet line 'Noa', by using the monosomic series of the regular line 'Mara'. 'Noa's' high number of spikelets was found to be controlled by a recessive major gene on chromosome 2D; a slight reduction in spikelet number was induced by another recessive gene on 'Noa's' 7A chromosome. 'Noa's' late heading date was found to be controlled by two recessive genes, located on chromosome 2D (a major effect) and 6B (a minor effect). The nature of the genes located on 'Noa's' 2D chromosome and the relationship between spikelet number and heading date are discussed.

Genetic control of heading date and spikelet number in common wheat (T. aestivum L.) line 'Noa'.

The phenology and build-up of spikelet number under 10 h day-length were studied in five wheat lines: the multispikelet line 'Noa', the regular line 'Mara', the F1 hybrid between them and monosomics 2D of 'Mara' and of this hybrid (lacking the 2D chromosome of 'Mara'). 'Noa' had a longer spike development phase, a higher initial number of spikelet primordia and a slower rate of spikelet production than 'Mara'. The F1 hybrid was similar to 'Noa' in its high initial number of spikelets and to 'Mara' in its high rate of spikelet production. This hybrid had a shorter spikelet phase than both parents. Deletion of one dose of the 'Mara' 2D chromosome from either 'Mara' or the F1 hybrid caused a reduction in the rate of spikelet production and an increase in the duration of the spikelet phase. These effects were due to the reduced dosage of the 2D chromosome. However, in the F1 hybrid this deletion also caused an increase in the spike development phase - an indication that 'Noa' carries on its 2D chromosome a recessive gene for late heading date which acts on the spike development phase. This gene of 'Noa' is independent of the day-length sensitive gene ppd, and is different from 'Noa's dominant gene for large initial number of spikelets.

Evidence for maternal effect in the inheritance of grain protein in crosses between cultivated and wild tetraploid wheats.

Reciprocal crosses were made between cultivated wheat (Triticum turgidum var. 'durum') and a high-protein line of wild tetraploid wheat (T. turgidum var. 'dicoccoides'). F1 grains (on maternal spikes) were very similar to the selfed grains on the maternal parent in protein percentage, weight and protein content. These traits were also analyzed in F3 grains developed on F2 spikes of segregating populations derived from reciprocal crosses between the same cultivated parent and another high-protein line of var. 'dicoccoides'. No significant differences in the mean values of these traits were found between the reciprocal crosses, indicating no cytoplasmic effect. It has been concluded that these grain characteristics are largely determined by the maternal plant.

Genotypic effects of the maternal tissues of wheat on its grain weight.

Reciprocal crosses were made between semi dwarf spring wheat cultivars (Triticum aestivum L.) differing in grain weight. The weights of the F1 grains (on maternal spikes), from intact as well as from defoliated plants, and those of the F2 grains (on f1 spikes), were examined. Grain weight was controlled primarily by the genotype of the maternal tissues (pericarp, testa or other floret or spikelet organs, including the vascular system), with complete dominance of heaviness. No indications suggesting maternal inheritance were obtained. The frequency distribution of the weights of the F2 grains indicated the presence of genotypic effects exerted by the endosperm or embryo. The embryo or endosperm factors for heaviness also seemed to be dominant.