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Biomedical subjects

M Ohki

Publications and source records attributed to M Ohki.

At least 163 records · Page 9Linked to original sources
PubMed1987

Primary leiomyosarcoma of bone. A case report and review of the literature.

A 62-year-old female with primary leiomyosarcoma of the left femur is reported with a review of 21 cases reported in the literature. The resected specimen showed that the tumor extended from the femoral head to the diaphysis for 13 cm in length. The tumor showed mainly intramedullary proliferation, but extraosseous growth was also noted at the great trochanter. Microscopic examination revealed well differentiated leiomyosarcoma characterized by interlacing bundles of fusiform cells with eosinophilic cytoplasm and rod-shaped hyperchromatic nuclei. PAP stain of actin on the tumor cells was positive. On electron microscopy, microfilament of 6-8 nm in diameter, dense bodies, pinocytotic vesicles, marginal attachment plate, and basal lamina were noted. The patient died with pulmonary metastasis, 1 year and 7 months after the operation. An autopsy showed metastases in the right pelvic cavity and bilateral lungs, and confirmed the primary site to be the left femur.

Female↗
PubMed1986

Nucleotide sequence of the Escherichia coli dnaJ gene and purification of the gene product.

The dnaJ and dnaK genes are essential for replication of Escherichia coli DNA, and they constitute an operon, dnaJ being downstream from dnaK. The amount of the dnaJ protein in E. coli is substantially less than that of the dnaK protein, which is produced abundantly. In order to construct a system that over-produces the dnaJ protein, we started our study by determining the DNA sequence of the entire dnaJ gene, and an operon fusion was constructed by inserting the gene downstream of the lambda PL promoter of an expression vector plasmid, pPL-lambda. Cells containing the recombinant plasmid produced dnaJ protein amounting to 2% of the total cellular protein when cells were induced. The overproduced protein was purified, and Edman degradation of the protein indicated that the NH2-terminal methionine was found to be processed. From the DNA sequence of the dnaJ gene, the processed gene product is composed of 375 amino acid residues, and its molecular weight is calculated to be 40,975.

Amino Acid Sequence↗
PubMed1986

Endotoxin-inactivating activity in normal and pathological human blood samples.

The endotoxin-specific chromogenic test revealed that plasma endotoxin-inactivating activity was markedly diminished by endotoxemia, but not by fungemia or by dialysis with cellulose membranes, suggesting that fungal polysaccharides and other nonendotoxic, Limulus-reactive materials do not consume endotoxin-inactivating factors in the blood. There was a close negative correlation between plasma endotoxin concentration and endotoxin-inactivating activity. The specificity of the test was improved by fractionating amebocyte lysate and using only the factors that constitute the endotoxin-sensitive coagulation pathway of the horseshoe crab. This test was able to differentiate endotoxemia from fungemia and from contamination with other nonendotoxic, Limulus-reactive materials.

Endotoxins↗
PubMed1986

Studies of transnasal pressure and airflow values in a Japanese population.

The proportions of subjects who attained transnasal pressure and flow values of different magnitudes during spontaneous nasal breathing at rest were determined. Several co-ordinate points on transnasal pressure: flow curves generated by 77 (34 M, 43 F) healthy Japanese subjects aged 15-65 years were examined. By posterior rhinomanometry the proportion approximated 100% at Brom's radii R1 and R2 and 80-90% at 0.25 l/sec flow and at 0.5 cm H2O (50 Pa) pressure when both nasal cavities were patent. When one nasal cavity was occluded the results were 100% at radius R1 and 80-90% at radius R2 and 0.5 cm H2O (50 Pa) pressure. By anterior rhinomanometry, the proportion approximated 100% at radius R1 and 0.5 cm H2O (50 Pa) pressure and was quite high at radius R2 and 1.0 cm H2O (100 Pa) pressure. Pressure and flow are more representative at points where the pressure: flow curve includes the turbulent flow component than at radius R1 and 0.5 cm H2O (50 Pa) pressure. Calculation of total nasal resistance from unilateral resistances at 1.0 cm H2O (100 Pa) appears a suitable compromise and this point is recommended for a Japanese population.

Adolescent↗
PubMed1985

A new chromogenic endotoxin-specific assay using recombined limulus coagulation enzymes and its clinical applications.

A conventional limulus test is not specific to endotoxin because of the presence in amebocyte lysate of a (1----3)-beta-D-glucan-sensitive factor. By fractionating coagulation enzymes in the lysate and recombining only those factors involved in endotoxin-induced coagulation, we have developed a new test specific to endotoxin. The recombined enzymes reacted only with endotoxin, and not with fungal polysaccharides. Conventional amebocyte lysate, on the other hand, reacted with both of them. A good linearity was obtained with this method between endotoxin concentration and absorbance with a sensitivity of 1 pg/ml of Escherichia coli 0111:B4 endotoxin. The regression lines for different types of endotoxins were parallel to one another. For the correct diagnosis of endotoxemia, this new test has a definite advantage over the one using whole amebocyte lysate.

Arthropod Proteins↗
PubMed1985

Exercise-induced change of nasal resistance in asthmatic children.

Exercise-induced change of nasal resistance and forced expiratory volume in 1 second (FEV1.0) were studied in 30 asthmatic children and seven normal children. Exercise-induced asthma (EIA) was diagnosed in 19 (63%) of the 30 asthmatic patients. Unilateral complete nasal blockage after exercise (exercise-induced nasal obstruction [EINO]) was found in nine (30%) of the 30 asthmatic patients. A marked decrease in nasal resistance took place immediately or 4 minutes after exercise in all cases. EIA is most severe 5 minutes after exercise, and EINO took place 14 or 19 minutes after exercise. The seven normal children had neither EIA nor EINO. The pathophysiologic relationship between EIA and EINO is discussed.

Adolescent↗
PubMed1984

The E. coli divE mutation, which differentially inhibits synthesis of certain proteins, is in tRNASer1.

The temperature-sensitive divE mutant of Escherichia coli cannot synthesize certain membrane and cytoplasmic proteins at a non-permissive temperature. Growth of the mutant cells is arrested at a specific stage of the cell cycle when exposed to the non-permissive conditions, suggesting that the divE mutant possesses a defect in cell division control. From sequence determination of a cloned 1.35-kbp DNA fragment that complements the temperature-sensitive divE42 mutation, we characterized two genes in the segment ; one for tRNASer1 and the other for a 23 500 dalton protein. In parallel experiments we cloned the homologous 1.35-kbp DNA fragment from the divE42 mutant and determined its entire nucleotide sequence. Comparison of the two sequences showed that the mutation site is located not in the protein gene, but in the tRNA gene, where A10 is replaced by G10 in the D-stem. Lambda transducing phages carrying the subcloned tRNASer1 gene complemented the divE42 mutation, thereby confirming the conclusion obtained from sequence analyses of the fragments. This finding indicates that tRNASer1 is specifically involved in regulation of cell cycle-specific protein synthesis, coupled with an important step in the process of cell division, or that usage of serine tRNA is functionally specific for the biosynthesis of certain proteins.

Bacterial Proteins↗
PubMed1983

The nucleotide sequence of Bacillus subtilis tRNA genes.

Clones carring Bacillus subtilis tRNA genes were isolated from a lambda 816 library. A recombinant phage lambda 816-BS83 which was hybridized effectively with unfractionated tRNA probes contained a 3-kb fragment. By a Southern's blot analysis, it was found that tRNA genes were located in Eco RI-Hinc II region of this fragment. Sequence determination revealed the presence of a cluster of four tRNA genes in this region. The gene organization was as follows: tDNALys-9bp-tDNAGlu-81bp-tDNAAsp-30bp-tDNAPhe. The RNA sequences expected from tDNALys and tDNAPhe were identical with the reported RNA sequences. Two tRNA genes, tDNALys and tDNAAsp encoded the CCA sequence of 3'-terminal region, but the other two, tDNAGlu and tDNAPhe did not. A promoter-like sequence which corresponds to the sigma 55-recognition site was found in a region about 100bp upstream from tDNALys.

Bacillus subtilis↗
PubMed1983

Pyridazinones. 2. Synthesis and antisecretory and antiulcer activities of thiourea and 2-cyanoguanidine derivatives.

In an effort to develop new types of antiulcer agents, we synthesized a series of novel 2-[omega-(thioureido)alkyl]- and 2-[omega-(cyanoguanidino)alkyl]-3(2H)-pyridazinone derivatives. All target compounds were evaluated for gastric antisecretory activity in the pylorus-lygated rat by the method of Shay, and selected compounds were evaluated in the stress-induced ulcer test in rats. Structure-activity relationships were established. Two series of the compounds had significant activity in antisecretory and/or antiulcer tests. The molecular features essential for the activities are a thiourea group or a 2-cyanoguanidine group, a phenyl group in the C-6 position of the 3(2H)-pyridazinone ring, a four-carbon chain length between the 3(2H)-pyridazinone ring and the functional group, and a methyl group at the N-3 position of the functional group. Among them, the three thiourea derivatives (24, 26, and 38) and the six 2-cyanoguanidine derivatives (61, 62, 65, 75, 85, and 86) had the most potent antisecretory and/or antiulcer activities. These compounds are not histamine H2-receptor antagonists.

Acetylcholine↗
PubMed1983

Pyridazinones. 3. Synthesis, antisecretory, and antiulcer activities of 2-cyanoguanidine derivatives.

3(2H)-Pyridazinone derivatives having a 2-cyanoguanidine moiety, as well as a sulfur or an oxygen atom in the alkylene side chain, were synthesized and evaluated for gastric antisecretory and antiulcer activities. The key intermediates, free amines having a thioether linkage, were synthesized by the reaction of 2-(omega-chloroalkyl) derivatives with cysteamine, while other intermediates having an ether linkage were synthesized from 2-(omega-chloroalkyl)oxymethyl derivatives. These free amines were converted via the 3-cyano-2-methyl-1-isothiourea derivatives into the desired 2-cyano-3-substituted-1-guanidine derivatives. All compounds synthesized were evaluated for gastric antisecretory activity in the pylorus-ligated rat by the method of Shay, and selected compounds were evaluated in the stress-induced ulcer test in rat. Structure-activity relationships are discussed. The molecular features for the best activities are a phenyl group in the C-6 position of the 3(2H)-pyridazinone ring, a four-atom chain length between the 3(2H)-pyridazinone ring and the 2-cyanoguanidine moiety, and a thioether rather than an ether linkage. Among them, compound 14, 2-[[[2-(2-cyano-3-methyl-1-guanidino)ethyl]thio]methyl]-6-phenyl-3 (2H)-pyridazinone, had the most potent antisecretory and antiulcer activities. These compounds are neither histamine H2 receptor inhibitors nor anticholinergic agents.

Animals↗
PubMed1983

Nucleotide sequence of the regulatory region of malB operons in E. coli.

The nucleotide sequence of a cloned section of the Escherichia coli chromosome containing the promoter regions of the malB divergent operons was determined. The region of the proximal gene, malE of the malEFG operon, was identified on the basis of the known amino acid sequence of the precursor molecule of maltose-binding protein. The region of malK, the proximal gene of the malKlamB operon, was deduced from the observation that a cloned segment contains an amino-terminal portion of the malK gene. The non-coding region between malE and malK is 299 base pairs long and contains two long GC clusters. Another feature of this region that may be related to the regulation of gene expression is the presence of two palindromic structures between the GC clusters. The DNA regions binding to cyclic AMP binding protein were determined by a method using polyacrylamide gel electrophoresis. The sites are thought to be located close to GC clusters.

Base Sequence↗