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Biomedical subjects

K Oka

Publications and source records attributed to K Oka.

At least 469 records · Page 26Linked to original sources
PubMed1986

Hemangiomas of the central nervous system in Japan: an epidemiological and clinicopathological study with special reference to venous and cavernous malformations.

Our experiences with cerebrovascular malformations in Japanese patients have been reviewed, presenting 29 cases of venous malformation, 30 cases of cavernous angiomas and one case of capillary telangiectasis. We also present the data from the 763 cases of AVM obtained in the cooperative studies which were supported by the Ministry of Health and Welfare of Japan, and discussed the epidemiological and clinicopathological aspects in relation to those reported in the literature. The cooperative studies on these subjects were primarily done in conjunction with the investigation of Moya-Moya disease which is by far frequently found in Japan. Regarding the vascular malformations of the C.N.S., there seem to be no noticeable differences in the epidemiological aspects as seen in Japan and in other countries. It should be stressed also from our experiences that all kinds of vascular malformation, either intracranial or intraspinal, bleed probably more often than we expect. Neurosurgeons should pay more careful attention to these vascular malformations with appropriate concepts of the disease.

Adolescent↗
PubMed1986

Mandibular ameloblastoma with intracranial extension and distant metastasis.

A case of mandibular ameloblastoma which invaded intracranially through the skull base and developed distant metastasis to the femur is reported. The intracranial extension of the tumor was partially removed three times and the metastasis of the femur was curetted. The remaining tumor temporarily responded to chemotherapy, but the patient died of intracranial tumor regrowth. The period from the initial treatment of the mandibular tumor to death was 21 years.

Adult↗
PubMed1986

Presence and formation of codeine and morphine in the rat.

Endogenous codeine and morphine were identified in rat brain by immunological determination following HPLC. To demonstrate occurrence of a biosynthetic pathway to morphine in mammals similar to that used by the poppy plant, (+)-salutaridine, (-)-thebaine, and (-)-codeine were administered to rats intravenously. These compounds, which are intermediates in the synthesis of morphine in Papaver somniferum, caused a marked increase in the codeine and morphine levels in rat tissues. This provides evidence for a biosynthetic pathway to morphine in mammalians.

Animals↗
PubMed1986

A case report of mantle zone lymphoma progressing into follicular lymphoma.

The authors report a case of mantle zone lymphoma (MZL) progressing into follicular lymphoma (FL) with macroglobulinemia (IgM, lambda). At a first lymph node biopsy, a diagnosis of MZL was made on the basis of the presence of vague neoplastic nodules, consisting of small lymphoid cells and small cleaved cells. At a second lymph node biopsy, nodules of follicular lymphoma were observed in the central zones of the vague neoplastic nodules. At a third biopsy, the central zones were found to expand, revealing FL dominant pattern. The progress of FL from MZL also was suggested by sIg, AIPase, anti-CALLA (common acute lymphoblastic leukemia antigen) antibody, and anti-DRC (dendritic reticulum cell) antibody findings. Consequently, this is suggested to be a neoplasm of B-lymphocytes differentiating from small lymphocytes in the primary follicle or the mantle zone of secondary follicle into germinal center cells. The anti-DRC antibody findings suggest the neoplastic cells of FL induce DRC as the neoplastic stroma.

Adult↗
PubMed1986

[A study on the antibacterial activity of amniotic fluid--the significance of intraamniotic transferrin].

In order to study the antimicrobial activity of amniotic fluid, attempts were made to evaluate the in vivo growth of bacteria in amniotic fluid and the role of transferrin in antibacterial activity. The bacteria chosen for these experiments were Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus faecalis, respectively. The results obtained were as follows: Amniotic fluid was shown have an antibacterial effect on Escherichia coli and Staphylococcus aureus, while Pseudomonas aeruginosa and Streptococcus faecalis proliferated readily in amniotic fluid. Individual difference in each sample appeared to be responsible for the inconsistent potency of the inhibitory effect observed. When amniotic fluid was heated at 100 degrees C for 5 minutes, the antibacterial activity was lost. The level of transferrin in amniotic fluid obtained at term was determined to be 29.1 +/- 17.6mg/dl (N = 90). The value correlated with neither those measured in cord sera nor maternal sera. The antimicrobial activity was restored by adding transferrin into heat-treated amniotic fluid at a concentration of 250mg/dl or higher. Simultaneous addition of transferrin and a sufficient concentration of iron made it possible to form a transferrin-iron complex. A subsequent decrease in unbound transferrin resulted in the loss of antibacterial properties.

Amniotic Fluid↗
PubMed1985

Immunoelectron microscopic study of Hodgkin's disease.

Seven patients with Hodgkin's disease were studied for the presence of lysozyme and alpha-1-antitrypsin activity by immunoelectron microscopy. As a result, Reed-Sternberg cells, Hodgkin's cells, and atypical cells were distinctly positive for lysozyme in four cases and weakly positive in the remaining three cases. These cells were also positive for alpha-1-antitrypsin in all cases. Because the cells of the monocyte-macrophage lineage also bore lysozyme and alpha-1-antitrypsin, it is suggested that Reed-Sternberg cells, Hodgkin's cells, and the atypical cells are derived from the monocyte-macrophage lineage.

Histocytochemistry↗
PubMed1985

Efficient chromatographic fractionation of steroids in human serum through regulation of liquid--liquid distribution ratios.

To improve the clean-up process in the analysis of biological fluid constituents, an efficient liquid--liquid distribution system was developed. Closed-bed columns containing fine diatomaceous earth granules were prepared by slurry packing for the fractionation of steroid hormones in human serum before quantitative assay by liquid chromatography or radioimmunoassay. Four columns were connected to construct the aqueous liquid--liquid chromatography--fractionation system. The first was coated with neutral water for distribution of serum, the second was weakly alkaline with sodium hydrogen carbonate for extrusion of strong acidic components, and the third was strongly alkaline with sodium hydroxide to capture oestrogens. The final column was acidic with sulphuric acid to remove basic components. Optimization of the stepwise gradient solvents was achieved on the basis of the results of a linear relationship between the logarithms of the capacity ratios and solvent composition determined from an analytical run. Neutral steroid hormones added to serum were eluted from the column system by a stepwise gradient elution technique to obtain first very non-polar materials, then progesterone and testosterone, and finally to extract the corticosteroids. Phenolic oestrogens were recovered from the strong alkaline column with a mobile phase solvent after the pH of the stationary phase had been adjusted with a phase transfer neutralizer. The fractional constituents were purified and enriched. This procedure was used to determine Solu-medrol, an acidic corticosteroid drug, in human serum.

Chromatography, Liquid↗
PubMed1985

Three-dimensional structure of the ribonuclease T1 X 3'-guanylic acid complex at 2.6 A resolution.

The mother enzyme of RNase T1 was co-crystallized with its natural product, 3'-GMP at pH 4.0. The X-ray structure of this complex was refined with 2432 reflections in the 5.4-2.6 A range using a stereochemical restrained method (conventional R = 27.4%). The overall polypeptide chain folding is very similar in the secondary structure elements to the RNase T1 in the complex with 2'-GMP crystallized also at pH 4.0, but larger conformational changes occur in the loop regions. The base recognition scheme is identical in both complexes but in RNase T1 X 3'-GMP, the ribose phosphate is not seen in the electron density, probably due to static disorder.

Chemical Phenomena↗
PubMed1985

In vitro degradation of oxytocin by pregnancy serum, placental subcellular fractions and purified placental aminopeptidases.

The degradation of oxytocin (formula; see text) by human placental particulate and soluble fractions, pregnant and non-pregnant sera, and purified enzymes such as microsomal placental leucine aminopeptidase (P-LAP), retroplacental serum P-LAP and placental post-proline endopeptidase, was studied by measuring liberated amino acids with a high performance liquid chromatograph (HPLC). While the placental particulate fraction degraded oxytocin almost completely into single amino acid and amide, the placental soluble fraction did not liberate any amino acid and amide. Purified retroplacental P-LAP liberated Tyr2, Ile3, Gln4 and Asn5 from the cyclic structure of oxytocin actively. Pregnancy serum containing the retroplacental P-LAP liberated also these amino acids and amides. Purified microsomal P-LAP liberated Leu8 in addition to these amino acids and amides. Although purified placental post-proline endopeptidase or porcine kidney leucine aminopeptidase (LAP) could not liberate any amino acid and amide from oxytocin, the combination of the post-proline endopeptidase with porcine kidney LAP or with placental microsomal P-LAP actively liberated all amino acids and amides detectable by HPLC. When the ratio of amino acid liberation velocity to LAP activity measured with leu-p-nitroanilide was calculated, the ratios for cyclic amino acids such as Tyr2 and Ile3 were high with the placental particulate fraction, the mixture of post-proline endopeptidase and microsomal P-LAP, retroplacental P-LAP, and pregnancy serum. The ratio for Leu8 was high with the placental particulate fraction and the mixture of post-proline endopeptidase and microsomal P-LAP.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1985

Isolation of morphine from toad skin.

A nonpeptide opioid was found in toad skin and purified to homogeneity by using HPLC with electrochemical detection. A nonpeptide opioid also was detected in bovine brain and adrenals as well as rabbit and rat skin, by reversed-phase HPLC following Sephadex G-15 column chromatography. The material in toad skin was identical to morphine by immunological, pharmacological, and physical chemical criteria.

Adrenal Glands↗
PubMed1985

Determination of pipemidic acid in plasma by normal-phase high-pressure liquid chromatography.

An improved high-pressure liquid chromatography procedure for determining the concentration of pipemidic acid in human plasma was developed, which uses a normal-phase silica gel column and aqueous mobile solvent system similar to that used in reverse-phase chromatography. Precolumn derivatization of pipemidic acid was achieved by a methylation reaction with boron trifluoride in methanol after extraction from plasma with chloroform containing 4% ethanol. The percent recovery of pipemidic acid was 88.3 +/- 7.7, the variation of which became negligible when quinacrine was used as an internal standard for the determination. High-pressure liquid chromatography analysis was performed by conventional silica gel and mobile solvent mixtures containing 3% of 0.14% HClO4 solution, 19% methanol, and 78% chloroform. The UV detector was set at 265 nm. The detection limit of pipemidic acid methyl ester was as low as 10 ng of the injection amounts or 0.5 micrograms of the plasma per ml, with 0.01 absorbance units (full scale) and a signal-to-noise ratio of 3.

Adult↗
PubMed1985

Microsurgical anatomy of the superficial veins of the cerebrum.

The microsurgical anatomy of the superficial cortical veins was examined in 20 cerebral hemispheres. The superficial cortical veins are divided into three groups based on whether they drain the lateral, medial, or inferior surface of the hemisphere. The veins on the three surfaces are further subdivided on the basis of the lobe and cortical area that they drain. The superficial cerebral veins collect into four groups of bridging veins: a superior sagittal group, which drains into the superior sagittal sinus; a sphenoidal group, which drains into the sphenoparietal and cavernous sinuses on the inner surface of the sphenoid bone; a tentorial group, which converges on the sinuses in the tentorium; and a falcine group, which empties into the inferior sagittal or straight sinus or their tributaries. The superior sagittal group drains the superior part of the medial and lateral surfaces of the frontal, parietal, and occipital lobes and the anterior part of the basal surface of the frontal lobe. The sphenoidal group drains the parts of the frontal, temporal, and parietal lobes adjoining the sylvian fissure. The tentorial group drains the lateral surface of the temporal lobe and the basal surface of the temporal and occipital lobes. The falcine group drains an area that includes the cingulate and parahippocampal gyri and approximates the cortical parts of the limbic lobe of the brain. The relationship of these veins to the venous lacunae was also examined.

Adult↗
PubMed1985

[A case of abdominal wall fistula due to cholangioma].

A 59-year-old woman was admitted to our hospital complaining of intractable abdominal wall fistula. Several examinations led to the suspicion of a fistula due to liver cell tumor. Histologically, the tumor was diagnosed as cholangioma. Chemotherapy was very effective after fistulectomy, and to date, she has been doing well for 34 months.

Abdominal Muscles↗