Biomedical subjects
Publications and source records attributed to A Yokota.
The authors present a case in which a cavernous sinus (CS) hemangioma was totally removed following intratumoral injection of a plastic fixation material. This unique method is extremely useful for the removal of CS hemangiomas, which often feature massive intraoperative bleeding as an unsolved problem.
The mainstay of treatment for patients with localized stage HD was historically radiation therapy. However, chemotherapy has been substituting radiation therapy because of remarkable effects of chemotherapy and the late adverse effects of radiation therapy. In the treatment of advanced stage HD, ABVD therapy is currently identified as the best chemotherapy on the basis of equivalent efficacy and reduced toxicity comparing with MOPP therapy. The newer, intensified regimens such as escalated BEACOPP or Stanford V have demonstrated excellent disease control in preliminary results. For patients with primary refractory or relapsed HD after chemotherapy, current data support the use of high-dose chemotherapy with autologous stem cell rescue.
An 18-year-old man suffered severe neck pain, signs of meningeal irritation, and dysesthesia of his left breast and left arm after mild head injury incurred in a traffic accident. On the next day, magnetic resonance imaging(MRI) revealed a hematoma in the cisterna magna, and it extended into the posterior spinal subdural space. Eight days after admission, MRI demonstrated the hematoma on the right posterior aspect of the spinal cord at the level of craniovertebral junction. These MRI findings suggested a ruptured bridging dorsal vein from the spinal cord to the occipital or marginal sinus. The usefulness of MRI for diagnosis of localized hematoma around the craniovertebral junction and the mechanism of this hemorrhage are discussed.
A case of symmetrical aneurysms at the bilateral middle cerebral arteries (MCA) associated with the deep seated arteriovenous malformation (AVM) in the midline was presented. Because symmetrical aneurysms at the MCA are 1.17% of all aneurysms, and those associated with the deep seated AVM in the midline are very rare. A 75-year-old female suffered from a sudden onset of a severe headache and a loss of consciousness, and was admitted to our department on June 14, 1996. Computed tomography(CT) showed a subarachnoid hemorrhage (SAH) in the right sylvian fissure (Fisher's Group 4). Bilateral symmetrical MCA's aneurysms and the deep seated AVM were clarified by angiography. The symmetrical aneurysms stood out anterior lateral side and the right aneurysm had bleb. On the other hand, the afferent vessels of the AVM were the branches of bilateral posterior cerebral arteries, and the efferent vessel was the vein of Galen. So we determined SAH due to right MCA aneurysm, and performed the neck clipping of the ruptured aneurysm. The symmetrical aneurysms at the MCA associated with AVM in midline have not been reported. Each parent's artery was not connected each other. These origins, therefore, are suggested to be related not only to acquired factors like hypertension, hemodynamic stress etc, but also to a congenital factor. The origin of the saccular aneurysm is suggested congenital either but it isn't definite.
Here we report a case of bitemporal epilepsy that was well controlled after unilateral temporal lobectomy. The patient was a 31-year-old woman, who was born in an asphyxia state and had a history of a febrile convulsion. Complex partial seizure(CPS) preceded by abdominal aura appeared at the age of three. Despite anticonvulsant medication, the seizures gradually increased in frequency and sometimes developed into secondary generalized convulsions. Her scalp electroencephalogram(EEG) showed interictal spikes and seizure activities arising from the bilateral temporal lobes. No apparent lateralities in regard to the size or blood flow at the hippocampus were detected by MRI and SPECT studies. Intracranial EEG monitoring revealed that 80% of the clinical seizures originated from the left mesial temporal lobe, which was the non-dominant side for speech and memory functions as demonstrated by Wada test. Therefore, we performed a left temporal lobectomy that resulted in the complete disappearance of CPS. The present case exemplified the usefulness of intracranial EEG monitoring to clarify the dominant epileptic focus for surgery.
The non-Mendelian inheritance of organelle genes is a phenomenon common to almost all eukaryotes, and in the isogamous alga Chlamydomonas reinhardtii, chloroplast (cp) genes are transmitted from the mating type positive (mt(+)) parent. In this study, the preferential disappearance of the fluorescent cp nucleoids of the mating type negative (mt(-)) parent was observed in living young zygotes. To study the change in cpDNA molecules during the preferential disappearance, the cpDNA of mt(+) or mt(-) origin was labeled separately with bacterial aadA gene sequences. Then, a single zygote with or without cp nucleoids was isolated under direct observation by using optical tweezers and investigated by nested PCR analysis of the aadA sequences. This demonstrated that cpDNA molecules are digested completely during the preferential disappearance of mt(-) cp nucleoids within 10 min, whereas mt(+) cpDNA and mitochondrial DNA are protected from the digestion. These results indicate that the non-Mendelian transmission pattern of organelle genes is determined immediately after zygote formation.
A considerable amount (approximately 1.6 microg from 1 mg of dried nematode) of non-sulfated chondroitin, two orders of magnitude less yet an appreciable amount of heparan sulfate, and no hyaluronate were found in Caenorhabditis elegans nematodes. The chondroitin chains were heterogeneous in size, being shorter than that of whale cartilage chondroitin sulfate. The disaccharide composition analysis of heparan sulfate revealed diverse sulfation including glucosamine 2-N-sulfation, glucosamine 6-O-sulfation and uronate 2-O-sulfation. These results imply that chondroitin and heparan sulfate are involved in fundamental biological processes.
Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1. 39) obtained from a thermophilic red alga Galdieria partita has the highest specificity factor of 238 among the Rubiscos hitherto reported. Crystal structure of activated Rubisco from G. partita complexed with the reaction intermediate analogue, 2-carboxyarabinitol 1,5-bisphosphate (2-CABP) has been determined at 2.4-A resolution. Compared with other Rubiscos, different amino residues bring the structural differences in active site, which are marked around the binding sites of P-2 phosphate of 2-CABP. Especially, side chains of His-327 and Arg-295 show the significant differences from those of spinach Rubisco. Moreover, the side chains of Asn-123 and His-294 which are reported to bind the substrate, ribulose 1,5-bisphosphate, form hydrogen bonds characteristic of Galdieria Rubisco. Small subunits of Galdieria Rubisco have more than 30 extra amino acid residues on the C terminus, which make up a hairpin-loop structure to form many interactions with the neighboring small subunits. When the structures of Galdieria and spinach Rubiscos are superimposed, the hairpin region of the neighboring small subunit in Galdieria enzyme and apical portion of insertion residues 52-63 characteristic of small subunits in higher plant enzymes are almost overlapped to each other.
The amino acid sequence deduced from the open reading frame designated sll0755 in Synechocystis sp. PCC 6803 is similar to the amino acid sequences of thioredoxin peroxidases from other organisms. In the present study, we found that a recombinant SLL0755 protein that was expressed in Escherichia coli was able to reduce H2O2 and tertiary butyl hydroperoxide with thioredoxin from E. coli as the electron donor. Targeted disruption of open reading frame sll0755 in Synechocystis sp. PCC 6803 cells completely eliminated the H2O2-dependent and tertiary butyl hydroperoxide-dependent photosynthetic evolution of oxygen and the electron flow in photosystem II. These results indicate that the product of open reading frame sll0755 is a thioredoxin peroxidase whose activities are coupled to the photosynthetic electron transport system in Synechocystis sp. PCC 6803.
CD44 is a widely expressed cell surface glycoprotein with various functions. This molecule is shed from the cell surface and released as a soluble molecule. High serum levels of CD44 have been demonstrated in some solid tumours. In this study we measured serum CD44 in 25 patients with acute leukemia, in 12 with bacterial infections, and in 13 normal controls. The levels of serum CD44 of patients with bacterial infections were significantly higher (mean 531.3+/-60.1 ng/ml, p<0.001) than those of normal controls (299. 0+/-115.4 ng/ml). Acute leukemia patients before treatment had almost four-fold higher levels of serum CD44 than normal controls (mean 1301.9+/-1384.6 ng/ml, p<0.01). Serum CD44 levels were correlated with clinical status. After treatment the serum CD44 levels significantly decreased, but they were still higher than in normal controls. Patients in complete remission all relapsed if serum CD44 levels were higher than 500 ng/ml (normal+2 SD) after chemotherapy. The serum CD44 levels were correlated with the absolute numbers of leukemic cells in peripheral blood. The results demonstrated that serum CD44 levels correlate well with the clinical status of acute leukemia, and such evaluation may provide a reliable tumour marker of acute leukemia.
The effects of methylmercury chloride (MMC) on the degenerative changes in rat brain and cranial nerves were studied. Twelve Wistar rats were divided into two equal groups. The rat model of methylmercury intoxication (MMC group) was made by subcutaneously administering 10 mg mercury/g body weight daily for 7 days. Control group rats were infused with the same amount of normal saline during this period. Magnetic resonance imaging (MRI) measurements were performed before and 14 days after the first MMC administration, using a 4.7-T MR system. No significant focal changes were observed on T1- and T2-weighted MR images regarding the internal structures of the brains of the MMC-intoxicated rats, atrophy of the cerebellum, and dilatation of the arachnoid space around the brain stem of MMC-treated rats, but were demonstrated without edematous change. The apparent diffusion coefficients (ADC) of the cortex, caudate-putamen, and trigeminal nerve were not significantly different between the MMC-treated and control rats. However, the ADC parallel to the optic nerves were significantly increased in the MMC group, in contrast to the unchanged ADC perpendicular to the optic nerves. An electron microscopy study revealed a marked decrease of microtubules and moderate decrease of neurofilaments in the axons of myelinated fibers of optic nerves of the MMC-treated rats. We have thus demonstrated a disturbance in the integrity of microtubules and neurofilaments as a toxic action of MMC in the rat nervous system in vivo, particularly in the optic nerves. The use of ADC values calculated by diffusion-weighted MRI is a promising approach for the evaluation of changes in brains and nerves in methylmercury intoxication research.
A case of meningioma coexisting with both lipomatous and secretory components, the latter characterized by hyaline inclusion bodies, is reported. The neuroradiological features of lipomeningioma are reevaluated, and the possible pathogenetic mechanisms of this unique combination in the present case are discussed.
Although molecular phylogenetic studies of cyanobacteria on the basis of the 16S rRNA gene sequence have been reported, the topologies were unstable, especially in the inner branchings. Our analysis of 16S rRNA gene phylogeny by the maximum-likelihood and neighbor-joining methods combined with rate homogeneous and heterogeneous models revealed seven major evolutionary lineages of the cyanobacteria, including prochlorophycean organisms. These seven lineages are always stable on any combination of these methods and models, fundamentally corresponding to phylogenetic relationships based on other genes, e.g., psbA, rbcL, rnpB, rpoC, and tufA. Moreover, although known genotypic and phenotypic characters sometimes appear paralleled in independent lineages, many characters are not contradictory within each group. Therefore we propose seven evolutionary groups as a working hypothesis for successive taxonomic reconstruction. New 16S rRNA sequences of five unicellular cyanobacterial strains, PCC 7001, PCC 7003, PCC 73109, PCC 7117, and PCC 7335 of Synechococcus sp., were determined in this study. Although all these strains have been assigned to "marine clusters B and C," they were separated into three lineages. This suggests that the organisms classified in the genus Synechococcus evolved diversely and should be reclassified in several independent taxonomic units. Moreover, Synechococcus strains and filamentous cyanobacteria make a monophyletic group supported by a comparatively high statistical confidence value (80 to 100%) in each of the two independent lineages; therefore, these monophylies probably reflect the convergent evolution of a multicellular organization.
Bacillus ehimensis EAG1 (IFO15659) produced and secreted chitosanase in the presence of exogenous chitosan. The chitosanase was purified from the culture filtrate of the bacterium to apparent homogeneity in SDS-polyacrylamide gel electrophoresis. The purified enzyme had a molecular weight of approximately 31,000. A 1.9-kbp DNA fragment containing the chitosanase gene was cloned and the complete nucleotide sequence was determined. The sequence was found to contain a single open reading frame encoding a protein of 302 amino acids. The deduced amino acid sequence showed significant homology with the chitosanase from Bacillus circulans MH-K1.
Physiological and chemotaxonomical studies were carried out on microorganisms isolated from a composter operated at around 50 to 60 degrees C. Only gram-positive rods were isolated and the microbial counts on agar plates were relatively low (10(3) to 10(5) cfu/g-sample). The chemotaxonomic properties of the ten isolates revealed that they were typical of the genus Bacillus. Identification by the Biolog system concurred with the chemotaxonomy; all the strains were determined to be Bacillus. 16S rDNA analysis closely identified five of the isolates as B. licheniformis, one as B. subtilis, and two as B. thermoamylovorans, while the remaining two strains seemed to belong to a new species. However, in several cases 16S rDNA analysis and the Biolog system gave different results at the species level. The stability of microflora within the composter was also investigated using the Biolog system. Analysis of colonies obtained during three sampling periods--December 1997, April 1998, and June 1998--showed that the microflora in the composter remained fairly stable.
The taxonomic positions of 'Pseudomonas hydrogenothermophila' strain TH-1 and 'Flavobacterium autothermophilum' strain TH-4 were studied by 16S rDNA sequencing. These organisms are Gram-negative, strictly aerobic, thermophilic, facultatively chemolithoautotrophic hydrogen-oxidizing rods and have a DNA G + C content of 63-65 mol%. The major isoprenoid quinone is ubiquinone-8 and 3-hydroxy decanoic acid (3-OH C10:0) is the major 3-hydroxy cellular fatty acid. A phylogenetic analysis based on 16S rDNA sequences placed strains TH-1T and TH-4 in the beta-subclass of the Proteobacteria. The taxonomic characteristics of these organisms are different from those of previously described aerobic, facultatively chemolithoautotrophic, hydrogen-oxidizing bacteria that belong to the beta-subclass of Proteobacteria. On the basis of the information described above, a new genus and species, Hydrogenophilus thermoluteolus gen. nov., sp. nov., is described to include both strains. The type strain is strain TH-1T (= IFO 14978T).
The HY1 locus of Arabidopsis is necessary for phytochrome chromophore biosynthesis and is defined by mutants that show a long hypocotyl phenotype when grown in the light. We describe here the molecular cloning of the HY1 gene by using chromosome walking and mutant complementation. The product of the HY1 gene shows significant similarity to animal heme oxygenases and contains a possible transit peptide for transport to plastids. Heme oxygenase activity was detected in the HY1 protein expressed in Escherichia coli. Heme oxygenase catalyzes the oxygenation of heme to biliverdin, an activity that is necessary for phytochrome chromophore biosynthesis. The predicted transit peptide is sufficient to transport the green fluorescent protein into chloroplasts. The accumulation of the HY1 protein in plastids was detected by using immunoblot analysis with an anti-HY1 antiserum. These results indicate that the Arabidopsis HY1 gene encodes a plastid heme oxygenase necessary for phytochrome chromophore biosynthesis.
PURPOSE: To evaluate whether Doppler ultrasonographic (US) velocimetry in renal interlobar arteries is altered in women with pregnancy-induced hypertension (PIH) compared with that in healthy pregnant and nonpregnant women. MATERIALS AND METHODS: Flow waveform measurements in renal interlobar arteries were obtained in 39 nonpregnant women, 77 healthy pregnant women at 16-40 weeks gestation, and 15 women with PIH at 28-39 weeks gestation by using color and pulsed Doppler US. RESULTS: In the nonpregnant group, the mean (+/- SD) peak systolic velocity, end-diastolic blood flow velocity, resistive index, and acceleration time were 0.34 m/sec +/- 0.08, 0.14 m/sec +/- 0.03, 0.62 m/sec +/- 0.07, and 52.3 m/sec +/- 13.7, respectively. In the healthy pregnant group, the peak systolic and end-diastolic blood flow velocities at 16 weeks gestation had decreased greatly by 40 weeks gestation. However, the values of other indexes in this group did not change with gestational age. In the PIH group, the acceleration time values were greatly prolonged compared with those in the other groups. CONCLUSION: Acceleration time is one of the hemodynamic parameters of substantial upstream stenosis. These findings suggest that severe stenosis or continuous vasospasm in the proximal arteries, such as the main renal artery and segmental artery, might be implicated in the pathogenesis of PIH.