A human putative Suv3-like RNA helicase is conserved between Rhodobacter and all eukaryotes.

We have cloned and sequenced a cDNA of the human homologue of the Saccharomyces cerevisiae Suv3 putative RNA helicase which is indispensable for mitochondrial function in yeast. The human Suv-3-like protein has a typical mitochondrial leader sequence. Northern blot data and analysis of ESTs in the data banks indicate that this human gene (SUPV3L1) is expressed in practically all tissues, though at different levels. Sequence homology analysis has shown a strong conservation of the protein in a number of eukaryotic organisms -- plants, mammals and fungi, but no close homologues exist in bacteria with the exception of the purple bacterium Rhodobacter sphaeroides. This gene is thus ubiquitously present in all eukaryotic organisms.

Computed tomographic evaluation of the normal adult odontoid. Implications for internal fixation.

STUDY DESIGN: Computed tomography scans of the dens were performed on patients who had no atlantoaxial pathology. OBJECTIVES: To determine whether one or two screws is optimal for fracture fixation and whether two screws can always negotiate the intramedullary odontoid cavity. SUMMARY OF BACKGROUND DATA: Fixation of Type II dens fractures traditionally has used C1-C2 posterior wiring and fusion. Two screws placed across an odontoid fracture as a method of rigid internal fixation also has been described. However, it is not known whether two screws can always negotiate the odontoid canal. METHODS: Ninety-two consecutive computerized tomography scans of the dens were performed on adults who had no atlantoaxial pathology. Measurements were taken from the scan and compared with the cross-sectional diameter of two odontoid screws. RESULTS: The critical diameter for the placement of two 3.5-mm cortical screws with tapping was 9.0 mm. This dimension was present in 95% of the patients studied. CONCLUSIONS: Correct orientation of the computerized tomography scanner is critical for accurate measurements. Two 3.5-mm screws can be used in internal fixation of Type II dens fractures in 95% of the patients if the inner cortex is tapped.

MELAS as an example of a mitochondrial disease.

MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) is a disease mainly due to a mutation at position 3243 (A --> G) in the leucine tRNA gene in mitochondrial DNA. Symptoms of the disorder are complex and the exact pathogenesis is not understood. A review of the literature on the subject is presented.

Human mitochondria in health, disease, ageing and cancer.

In every human cell there are hundreds of mitochondria, which are required for oxidative phosphorylation as well as many other metabolic processes. Each mitochondrion contains approximately 5 mitochondrial DNA molecules. These circular DNAs of 16.5 kb in size contain only 39 genes. Mutations in mitochondrial DNA are responsible for many diseases. Alterations in these molecules may also play a role in ageing and in tumour formation.

[Mitochondrial diseases--causes and diagnosis]. / Choroby mitochondrialne--przyczyny i diagnostyka.

Increasing numbers of diseases due to disturbances in mitochondrial DNA (mtDNA) are being discovered. Mutations in mtDNA mainly cause malfunctioning of muscle and nerve cells. The most common diseases and their molecular diagnosis are briefly described.

Depth perception of surfaces in pictures: looking for conventions of depiction in Pandora's box.

The perception of depth in monocularly viewed pictures has been investigated with the use of a binocular rangefinder developed by Gregory. Two experiments are reported which focus upon stimulus conditions that were identified by Haber as conventions for rendering depth in pictures. Several conclusions, which concern assumptions that must be made in interpreting pictures according to such conventions, are supported by the results. There is a default or assumed layout of background space. The interpretation of a point in a depiction depends upon the interpretation of neighboring points, so that interpretations of local features influence the interpretations of nearby 'empty' areas. In photographs, the magnitude of apparent depth depends upon the degree of discrepancy between the position of the illuminating source and the observer's supposed light-source position. Also in photographs, apparent depth increases as the contrast between highlights and attached shadows increases.

T-DNA from Agrobacterium tumefaciens as an efficient tool for gene targeting in Kluyveromyces lactis.

The soil bacterium Agrobacterium tumefaciens can transfer a part of its tumour-inducing (Ti) plasmid, the T-DNA, to plant cells. The virulence (vir) genes, also located on the Ti plasmid, encode proteins involved in the transport of T-DNA into the plant cell. Once in the plant nucleus, T-DNA is able to integrate into the plant genome by an illegitimate recombination mechanism. The host range of A. tumefaciens is not restricted to plant species. A. tumefaciens is also able to transfer T-DNA to the yeast Saccharomyces cerevisiae. In this paper we demonstrate transfer of T-DNA from A. tumefaciens to the yeast Kluyveromyces lactis. Furthermore, we found that T-DNA serves as an ideal substrate for gene targeting in K. lactis. We have studied the efficiency of gene targeting at the K. lactis TRP1 locus using either direct DNA transfer (electroporation) or T-DNA transfer from Agrobacterium. We found that gene targeting using T-DNA was at least ten times more efficient than using linear double-stranded DNA introduced by electroporation. Therefore, the outcome of gene targeting experiments in some organisms may depend strongly upon the DNA substrate used.

Hemiplegic gait. Relationships between walking speed and other temporal parameters.

It has been asserted that speed alone is an effective indicator of the degree of gait abnormality. To determine the validity of this assertion, relationships between velocity and 18 other temporal gait parameters were determined in 25 patients with a first hemispheric stroke resulting in hemiplegia or hemiparesis of at least one month duration. Gait characteristics were recorded using footswitchs connected to a portable computerized monitoring device. Velocity was found to be significantly correlated with cadence, mean cycle duration, mean cycle length, hemiplegic limb stance phase duration, nonhemiplegic limb stance phase duration and percent, nonhemiplegic limb swing phase percent, double support phase duration and percent, hemiplegic limb swing/stance phase ratio, nonhemiplegic limb swing/stance phase ratio, and swing phase symmetry ratio but not with the hemiplegic limb stance phase percent, hemiplegic limb swing phase duration and percent, nonhemiplegic limb swing phase duration, stance phase symmetry ratio, and overall asymmetry ratio. Velocity is related to most, but not all, of the other temporal measures of hemiplegic gait. A comprehensive gait evaluation should also include characterization of the degree of asymmetry and descriptions of individual phase durations and proportions (particularly hemiplegic stance and swing percentages).

Identification of supernumerary marker chromosomes derived from chromosomes 5, 6, 19, and 20 using FISH.

A large number of cases with supernumerary marker chromosomes (SMCs) should be compared to achieve a better delineation of karyotype-phenotype correlations. Here we present four phenotypically abnormal patients with autosomal marker chromosomes analysed by fluorescence in situ hybridisation using centromeric, telomeric, and unique sequence probes, as well as forward and reverse painting. We also report the first case, to the best of our knowledge, of an SMC derived from chromosome 5. Furthermore, a marker chromosome 20 in a patient with sex differentiation abnormalities, a double mar(6) in a boy with psychomotor retardation, and the association of r(19) with dup(21q21.2q22.12) are described. Although the mar(6) was very small, the presence of euchromatin was shown, suggesting that the partial trisomy of pericentric region derived sequences is implicated in the aetiology of the abnormal phenotypes.

The timer-logger-communicator gait monitor: recording temporal gait parameters using a portable computerized device.

A portable microprocessor-based device, the timer-logger-communicator (TLC), was adapted and connected to footswitches to monitor and record temporal gait parameters in 25 hemiplegic and 30 normal subjects. Controls walked at 1.36 m/s with symmetric gait. Hemiplegic subjects had a mean walking speed of 0.43 m/s, asymmetric gait, and varying proportions of time spent in each phase, consistent with previously reported gait parameters. Trends in objective gait measures more closely paralleled trends in functional ambulation classification than in Brunnstrom motor recovery stages. The TLC gait monitor is a useful instrument to measure temporal parameters of gait in the clinical setting.