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Biomedical subjects

H Okazaki

Publications and source records attributed to H Okazaki.

At least 307 records · Page 17Linked to original sources
PubMed1985

Lumbar spinal stenosis. Clinical features, diagnostic procedures, and results of surgical treatment in 68 patients.

Our experience with 68 patients with strictly defined, myelographically proven, surgically confirmed lumbar spinal stenosis seen over a 30-month period was reviewed. Pseudoclaudication was the commonest symptom (94%) and was described by patients as pain (93%), numbness (63%), or weakness (43%). Symptoms were frequently bilateral (68%) and generally relieved by flexing the lumbosacral spine. Neurologic abnormalities were found in a minority of patients and were usually mild. Electromyography showed one or more lumbosacral radiculopathies in 34 of 37 patients examined. Radiographic evidence of degenerative disk or joint disease was found in 63 patients. All patients had stenosis on myelography, with narrowing at L2, L3, and L4 being the commonest; 30% had multi-level stenosis. Two of ten computed tomograms were normal. Surgery was extensive; 72% of patients had three or more laminae removed. At a mean of 4 years after surgery, 84% of patients reported that surgery had yielded good to excellent results.

Adult↗
PubMed1985

Intracranial germ cell tumors: pathobiological and immunohistochemical aspects of 70 cases.

Seventy cases of histologically verified intracranial germ cell tumor were reviewed: 43 germinomas, 16 immature teratomas, seven mature teratomas, two embryonal carcinomas, one choriocarcinoma, and one yolk sac tumor. The male-to-female ratio was 2.6:1. The average age was 19 years in patients with germinoma, 11 years in patients with immature teratoma, and 17 years in patients with mature teratoma. Duration of symptoms averaged 19 months for germinoma, three months for immature teratoma, and 11 months for mature teratoma. Sixty-six lesions were located in the midline. Fifty-eight percent of the germinomas arose anterior to the pineal gland, whereas 29% of the immature and 14% of the mature teratomas were located anteriorly. The histologic appearance of the germinomas was indistinguishable from that of the usual testicular seminoma. The immature teratomas contained tissue from all three germ layers and exhibited morphologic features of fetal tissue. Of 14 immature teratomas, seven contained, in addition, foci of other malignant germ cell elements; thus, there were two teratocarcinomas, two lesions with germinoma and immature teratoma, two lesions with extensive rhabdomyoblastic differentiation in an immature teratoma, and one lesion with both germinoma and embryonal carcinoma in addition to immature teratoma. The seven mature teratomas consisted of fully differentiated epithelial and mesenchymal tissues. In 23 cases, immunoperoxidase stains for human chorionic gonadotropin (HCG), alpha-fetoprotein (AFP), and carcino-embryonic antigen (CEA) revealed patterns which, with minor exceptions, were essentially identical to those found in genital germ cell lesions. Survival was longest for patients with germinomas. In classifying germ cell tumors of the central nervous system, the World Health Organization's (WHO) classification of testicular germ cell tumors is preferable to its present classification of intracranial germ cell tumors.

Adolescent↗
PubMed1984

Nucleotide sequence of a cloned cDNA for proopiomelanocortin precursor of chum salmon, Onchorynchus keta.

We have isolated a cDNA clone encoding salmon proopiomelanocortin precursor. Polyadenylated RNA was isolated from pituitary neurointermediate lobes and used to construct a cDNA library. The library was screened with 17 mer of oligodeoxyribonucleotides specific for the hexapeptide sequence in salmon beta-endorphin I, Phe-Met-Lys-Pro-Tyr-Thr at positions 4-9 excluding the third nucleotide. One positive clone, pSSM17 containing an insert of 1303 base pairs (bp) was characterized. Sequence determination revealed that it possessed sequences covering the entire regions encoding ACTH and beta-lipotropin and that the mRNA had the same overall organization as those of other mammalian species, i.e., the following peptide hormones were arranged in order from 5' upstream, ACTH including alpha-melanotropin and corticotropin-like intermediate lobe peptide, beta-lipotropin including gamma-lipotropin, beta-melanotropin and beta-endorphin. Amino acid sequences for putative salmon ACTH, beta-, and gamma-lipotropin were predicted. Comparison of the salmon mRNA sequence with those of mammals showed that the regions of alpha- and beta-MSH are relatively homologous, but other regions are much less so, especially in the 3' nontranslated region where it is much longer and completely heterologous.

Amino Acid Sequence↗
PubMed1984

Heterogeneity of 3' nontranslated regions in proopiomelanocortin (POMC) precursor mRNA of chum salmon Onchorynchus keta: polymorphism of the gene.

Heterogeneity of salmon pituitary proopiomelanocortin (POMC) mRNA was shown by comparison of the nucleotide sequence of independently isolated cDNA clones encoding POMC, pSSM90, pSSM53 and pSSM17, the last of which was previously characterized. Newly isolated clones pSSM90 and pSSM53 contained inserts of 1228 and 666 base pairs, respectively (excluding poly(A)). Sequence analysis revealed that the former contained sequences coding for the carboxy half of putative corticotropin (ACTH), the whole region of beta-lipotropin (beta-LPH), and the entire 3' nontranslated region, while the latter contained only the 3' nontranslated region. Sequence comparison of the three clones revealed that there are some definite nucleotide changes in the 3' nontranslated regions, i.e., base replacements and base additions at multiple sites, whereas no single change was observed in the coding regions, thus demonstrating heterogeneity and hence polymorphism of the gene in the salmon genome.

Adrenocorticotropic Hormone↗
PubMed1984

Human brain phenol sulfotransferase: biochemical properties and regional localization.

Phenol sulfotransferase (PST) catalyzes the sulfate conjugation of catecholamines and phenol and catechol drugs. The human blood platelet contains a thermolabile (TL) form of PST that catalyzes the sulfate conjugation of dopamine and other monoamines and a thermostable (TS) form that catalyzes the sulfate conjugation of micromolar concentrations of phenol and p-nitrophenol. Experiments were performed to determine whether the brain contains forms of PST analogous to the TL and TS forms found in the human platelet, and to determine whether there are regional variations in human brain PST activity. We found that the human brain contains at least two forms of PST, forms that are similar to the platelet TS and TL forms of the enzyme with respect to substrate specificity, apparent Km constants, thermal stability, and sensitivity to inhibitors. Optimal conditions were determined for the measurement of these two activities in brain homogenates. The stability of PST activities in the human brain after death was determined in five samples of cerebral cortex that were obtained during clinically indicated neurosurgical procedures. An average of 76 +/- 8% and 80 +/- 9% (mean +/- SEM) of the basal TL and TS PST activities, respectively, remained in these five samples of cerebral cortex after 8 h of storage under simulated post-mortem conditions. Six human brains were then obtained less that 8 h after death from patients who had no neurological disease prior to death. The mean activities of the TL and TS forms of PST were measured in 17 different regions of the six brains. If the pituitary was excluded from consideration, TL and TS PST activities both varied approximately fivefold among these regions, and both activities were highest in cerebral cortex. However, the average TS activity in the anterior pituitary, a tissue of non-neural origin embryologically, was 6.5-fold greater than the highest average TS PST activity found in cerebral cortex.

Arylsulfotransferase↗
PubMed1984

Neurosurgical management of low-grade astrocytoma of the cerebral hemispheres.

The authors conducted a retrospective review of surgically treated, histologically proven cases of low-grade (Grade 1 or 2) astrocytomas. Follow-up analysis, with survival time as the end-point, was completed using multivariant statistical analysis. In the 461 cases of supratentorial low grade astrocytoma in this study, age of the patient at the time of surgery was by far the most important variable in predicting length of survival. Other variables correlating with increasing survival times were: gross total surgical removal, lack of major preoperative neurological deficit, long duration of symptoms prior to surgery, seizures as a presenting symptom, lack of major postoperative neurological deficit, and surgery performed in recent decades. The multi-variant regression analysis showed that radiation therapy was of clear benefit, primarily in older patients with incompletely removed tumors. For purposes of establishing prognosis and testing the results, a "score" was developed to predict survival times, based on the most important variables. The data in this study provide a basis for the analysis of future modes of management of low-grade gliomas.

Adolescent↗
PubMed1984

Inhibition of fatty acid synthesis by the antibiotic thiolactomycin.

The antibiotic thiolactomycin inhibits the growth of Escherichia coli K-12 and Pseudomonas aeruginosa 507 (beta-lactam supersensitive mutant). A micrograph of E. coli cells, which were grown at a sublethal concentration of thiolactomycin (20 micrograms/ml), revealed the morphological change with cell elongation. The effects of the antibiotic on syntheses of cellular constituents were studied by measuring the incorporation of labeled precursors into lipids and macromolecules. This antibiotic preferentially inhibited the incorporation of [14C]acetate into fatty acids and lipids. Addition of both palmitate and oleate, but not of either fatty acid alone, reversed the growth inhibition of P. aeruginosa by thiolactomycin. These findings support the conclusion that the effects of thiolactomycin are due to a specific inhibition of fatty acid synthetase.

Anti-Bacterial Agents↗
PubMed1984

Cephabacins, new cephem antibiotics of bacterial origin. I. Discovery and taxonomy of the producing organisms and fermentation.

Three Gram-negative bacteria produce new cephem antibiotics, named cephabacins, with unique 3-side chains. Cephabacins include F group antibiotics with a 7-formylamino substituent and H group antibiotics without the substituent. The producing bacteria were taxonomically characterized and designated as Lysobacter lactamgenus sp. nov. YK-90 and Xanthomonas lactamgena sp. nov. YK-278 and YK-280.

Bacteria↗
PubMed1984

Cephabacins, new cephem antibiotics of bacterial origin. II. Isolation and characterization.

Fifteen components of new antibiotics, cephabacins, were isolated from the culture filtrates of Lysobacter lactamgenus YK-90, Xanthomonas lactamgena YK-280 and X. lactamgena YK-278. They were purified by column chromatography using cation-exchange resins, activated carbon, high porous resins and cation-exchange Sephadex and by preparative reverse-phase HPLC. The basic, water-soluble antibiotics were characterized as having a cephem skeleton and oligopeptide(s) as a side chain constituent from their spectroscopic analyses and amino acid analyses.

Cephalosporins↗
PubMed1984

Cephabacins, new cephem antibiotics of bacterial origin. IV. Antibacterial activities, stability to beta-lactamases and mode of action.

Cephabacin F group antibiotics with a 7-formylamino substituent showed antibacterial activity against a wide variety of bacteria including beta-lactamase-producing clinical isolates and anaerobic bacteria. Cephabacin H group antibiotics without the substituent showed more potent activity against Gram-positive bacteria than cephabacin F group antibiotics, but were not active against Gram-negative bacteria producing beta-lactamases. Cephabacin F group antibiotics were highly resistant to hydrolysis by various types of beta-lactamases and showed strong inhibitory activity against a cephalosporinase of Proteus vulgalis GN 4413 due to the 7-formylamino substituent. Mode of action of cephabacin F1 and H1 was examined using Escherichia coli and Bacillus subtilis as the test organisms. They showed strong lytic activity against these organisms and inhibited their peptidoglycan synthesis. Cephabacin F1 had the highest affinity for penicillin-binding protein (PBP) 1 in E. coli and PBP 4 in B. subtilis. Cephabacins showed a protective effect in experimentally infected mice.

Bacteria↗