How to discriminate between vibration syndrome and local fatigue of motorcyclists

Motorcyclists who work in some offices sometimes complained of coldness, pain and numbness of upper limbs. We studied how to discriminate between vibration syndrome and local fatigue of the motorcyclists. Subjects are 42 motorcyclists of an office in Aichi prefecture. 25 of them held several letters in their left hand when they delivered the letters. They complained of coldness, pain and numbness in the left upper limbs more than in the right limbs (p less than 0.01). We think that it is the local fatigue rather than the disorder of vibration syndrome that causes such symptoms. So it is very important to recognize the existence of local fatigue in order to know how to discriminate between vibration syndrome and local fatigue of the motorcyclists.     

Glutamine Synthetase of the Human Brain: Purification and Characterization

Glutamine synthetase (GS) isolated from human brain formed a single band on sodium dodecyl sulfate-polyacrylamide gel with a molecular weight of 44,000. The enzyme had a specific activity of 179.2 U/mg protein when assayed by measuring the rate of the formation of gamma-glutamylhydroxamate using hydroxylamine as a substrate. In the presence of manganese ions, the relative activity of human brain GS was much lower than that of the sheep brain enzyme. The suppression of activity by increasing the ADP concentration, however, was less marked in the human enzyme than that in the sheep enzyme. Antibodies were raised in rabbits against the purified enzyme. The double-immunodiffusion technique disclosed cross-reactivities among GSs isolated from human, sheep, and rat brains, but the enzymes were not immunologically identical. Immunohistochemically, GS was localized in the cytoplasm of astrocytes in the human and rat brains and in pericentral hepatocytes of the liver.     

cDNA cloning of a novel heterogeneous nuclear ribonucleoprotein gene homologue in Caenorhabditis elegans using hamster prion protein cDNA as a hybridization probe.

The mammalian prion protein (PrPc) is a cellular protein of unknown function, an altered isoform of which (PrPsc) is a component of the infectious particle (prion) thought to be responsible for spongiform encephalopathies in humans and animals. The evolutionary conservation of the PrP gene has been reported in the genomes of many vertebrates as well as certain invertebrates. In the genome of nematode Caenorhabditis elegans, the sequence capable of hybridizing with the mammalian PrP cDNA probe has been demonstrated, predicting the presence of the PrP gene homologue in C.elegans. In this study, Southern analysis with the hamster PrP cDNA (HaPrP) probe confirmed the previous observation. Moreover, Northern analysis revealed that the sequence is actively transcribed in adult worms. Thus, we screened C.elegans cDNA libraries with the HaPrP probe and isolated a cDNA that hybridizes to the same sequence in C.elegans that hybridized with the HaPrP probe in the Southern and Northern analyses. The deduced amino acid sequence of this cDNA, however, is substantially homologous with heterogeneous nuclear ribonucleoprotein (hnRNP) core proteins rather than mammalian PrPc. The hnRNPs contain the glycine-rich domain in the C-terminal half of the molecule, which also seemed to be in PrPc at the N-terminal half of the molecule. Both of the glycine-rich domains are composed of tracts with high G + C content, indicating that these tracts may due to the hybridizing signals. These results suggest that this cDNA clone is derived from a novel hnRNP gene homologue in C.elegans but not from a predicted PrP gene homologue.     

Properties of the Escherichia coli RuvA and RuvB proteins involved in DNA repair, recombination and mutagenesis

The ruvA and ruvB genes constitute an operon, which is regulated by the SOS system and involved in DNA repair, recombination and mutagenesis. RuvA protein binds to both single-stranded and double-stranded DNA. RuvB protein has weak ATPase activity. RuvA bound to DNA greatly enhances ATPase activity of RuvB. UV-irradiation to supercoiled DNA further enhances the stimulatory effect of RuvA on the RuvB ATPase activity. In the presence of ATP the RuvA-RuvB complex has an activity that renatures cruciform structures formed by heating and gradually cooling supercoiled DNA with an inverted repeat. These findings suggest that the RuvA-RuvB complex interacts with an irregular conformation in damaged DNA and induces conformational changes in DNA using energy provided by ATP hydrolysis, so that it facilitates DNA repair, recombination and error prone replication.     

Chondrosarcoma of the trachea. A case report and literature review

The cytologic presentation of a case of chondrosarcoma of the trachea in a 72-year-old man is described. A mass detected on routine chest roentgenogram and defined by CT scan was used to make a touch imprint smear during partial tumor resection. The cytologic findings included round or polygonal cells with occasional binucleation, round hyperchromatic nuclei and prominent nucleoli, present in an amorphous pink-violet or light-blue background containing fragments of chondroid tissue. The histopathology was interpreted as a low-grade chondrosarcoma. Cartilaginous tumors of the trachea should be considered in the differential diagnosis of upper airway obstruction.     

A new hereditary single band variant of the Gc system

Summary A new single band variant (Gc Ar) or the Gc subtypes not identical with the known Gc variants has been detected in the plasma of a healthy blood donor by isoelectric focusing. Using this technique the variant is represented by a single band which has a similar isoelectric point to the Gc 1C2 anodal band. It is well known that the single band Gc phenotypes remain unaltered after neuraminidase treatment. Nevertheless, the new single band variant (Gc Ar) is altered after neuraminidase treatment as is Gc 2A3. After neuraminidase treatment, the Gc Ar band is affected and moved to the nearby position of the Gc 2 band. Investigation of the proband's family shows that the variant occurs combined with the common alleles Gc 1F, Gc 1S and that it has an autosomal dominant inheritance.     

Sodium- and Calcium-Dependent Spike Potentials in the Secretory Neuron Soma of the X-Organ of the Crayfish

Membrane characteristics of neuron somata in the medulla terminalis ganglionic X-organ of crayfish have been investigated with intracellular glass microelectrodes. The soma membrane developed action potentials with 10–20 mv of overshoot. Delayed rectification appeared at 10–20 mv above resting membrane potential. In 50% of the neuron somata examined, action potentials were observed in Na-free medium or TTX medium. The peak potential level of the spike in these media depended on the extracellular concentration of Ca ion. It increased with the Ca concentration. In low calcium media, the peak potential level of the spike varied with Na concentration. Action potentials of the X-organ-sinus gland tract disappeared after bathing in Na-free or TTX medium, suggesting that the conductive action potential was dependent on Na ions. From these results, it is concluded that there are two systems in the neuron soma, one of which responds to the Na ion and the other, to the Ca ion. Inhibitory innervation of the X-organ by the cerebral ganglion was manifested by IPSP's when the optic peduncle was stimulated. A postulated connection between the Ca-dependent spike and the release of hormone in X-organ neuron somata is discussed.     

Heptapeptide toxin production during the batch culture of two Microcystis species (Cyanobacteria)

Changes in the content of cyclic heptapeptide hepatotoxins called microcystins were investigated during batch culture of two Microcystis species using high performance liquid chromatography. After adsorption to ODS-silica gel cartridges and elution with methanol, the toxins were analyzed and quantified by HPLC. 35 μg per 100 mg dry cells of microcystin-RR, 34 μg of -YR and 43 μg of -LR were present at the beginning of the exponential growth phase of M. viridis. Microcystin-RR increased markedly towards the end of the exponential phase with the maximum content of 112 μg per 100 mg cells was measured at the late stage of the exponential phase. A remarkable increase of microcystin-YR from 130 μg per 100 mg cells to 1020 μg was observed during the exponential phase of a highly toxic strain of M. aeruginosa. However no clear differences were found in the pattern of change among the three toxins during the growth course.