Biomedical subjects

N Oda

Publications and source records attributed to N Oda.

At least 109 records · Page 6Linked to original sources

PubMed1994

[Periodical blood pressure variation during cardiopulmonary bypass--effects of cervicothoracic epidural anesthesia and phentolamine].

We studied the effects of cervicothoracic epidural anesthesia or intravenous phentolamine on periodical blood pressure variation during cardiopulmonary bypass in 12 adult patients undergoing open heart surgery under fentanyl anesthesia. Spontaneous periodical fluctuation of the blood pressure was analyzed by means of autoregressive power spectrum method. Amplitudes of the low frequency (0.02-0.15 Hz) component of the blood pressure variation amplitudes were calculated. The amplitudes decreased significantly 10 minutes after cervicothoracic epidural block with 15 ml of 2% lidocaine solution (P < 0.05), and after infusion of 0.4 mg.kg-1 of phentolamine (P < 0.05). Since amplitudes of the blood pressure variation were reduced by adequate epidural block or phentolamine, they are likely to reflect sympathetic vasomotor activity.

Adult↗

PubMed1994

Angiotensin II receptor subtypes in bovine and human ventricular myocardium.

Angiotensin II (AII) binding sites in bovine and human ventricular myocardium were characterized by a radioreceptor assay. The specific binding of [125I]AII to myocardial membranes appeared to be saturable, and it was of high affinity with apparent dissociation constants of 1.60 nM (bovine) and 1.09 nM (human). The Bmax values were 39.7 fmol/mg protein (bovine) and 6.07 fmol/mg protein (human). Both losartan (angiotensin type 1 receptor subtype selective antagonist) and PD123177 (the angiotensin type 2 receptor subtype selective antagonist) inhibited specific [125I]AII binding to bovine myocardium, and their Hill coefficients were less than unity. Nonlinear least-squares regression analysis has suggested the existence of two populations of [125I]AII binding sites that have high and low affinity for losartan or PD123177. The relative proportions of high- and low-affinity sites for losartan in bovine myocardium were 68% and 32%, and those for PD123177 were 33% and 67%, respectively. On the other hand, specific [125I]AII binding in human myocardium was inhibited by losartan with much lower affinity and also by PD123177 with higher affinity, compared with bovine myocardium. The Hill coefficients for both drugs were close to one. Dithiothreitol enhanced specific [125I]AII binding to bovine myocardium in the presence of losartan, but it reduced [125I]AII binding in the presence of PD123177. This agent markedly enhanced specific [125I]AII binding to human myocardium. Thus, it is possible that bovine myocardium has both angiotensin type 1 receptor and the angiotensin type 2 receptor subtypes of AII receptors whereas human myocardium has predominantly the angiotensin type 2 receptor subtype.

Aged↗

PubMed1994

[A plurihormonal adenoma: a case report].

A case of prolactinoma secreting growth hormone is reported. A 32-year-old woman was admitted to our hospital complaining of galactorrhea, amenorrhea and bitemporal hemianopsia. She showed hyperprolactinemia about 500ng/ml and elevated growth hormone level over 10ng/ml without clinical features of acromegaly. Static perimetry represented typical bitemporal hemianopsia better than kinetic perimetry in the early stage of this pituitary tumor. Her visual acuity was 1.0 on the right and 0.02 on the left. MR images showed the intra-and suprasellar mass lesion compressing the optic nerves especially on the left. Because her visual acuity deteriorated rapidly, trans-sphenoidal tumor resection was carried out twelve days after admission. Total removal was achieved. Postoperative MRI showed that the normal pituitary gland had been preserved. The patient's visual acuity recovered to 1.2 on the right and 0.9 on the left, and bitemporal hemianopsia improved remarkably. Postoperative course was uneventful and hormonal functions were normalized. Histological examination showed that the tumor was chromophobe adnoma. The adnoma cells showed immunopositivity for growth hormone, but not for prolactin. Such absence of prolactin granules within cytoplasm might be due to the difference in antigen produced by the adenomatous gland as compared with that produced by the normal gland. Although hyperprolactinemia is often observed in acromegaly, hypersecretion of growth hormone in prolactinoma as was found in this case is very rare in medical literature.

Adenoma, Chromophobe↗

PubMed1994

[Transverse sinus thrombosis in a patient with colon and rectal double cancers: a case report].

We report a case of transverse sinus thrombosis accompanied by colon and rectal double cancers. A 48-year-old male transferred to our department from the division of surgery due to deterioration manifested by headache after colectomy and low anterior resection of the rectum. There was bilateral papilledema and right upper homonymous hemianopsia. On admission all the laboratory data were within normal range. CT showed a left temporal mass lesion of heterogeneous density, which was suspected as being intratumorous hematoma in a metastasis. MRI revealed a left transverse sinus thrombosis. The left transverse and sigmoid sinuses were not opacified, but angiography showed that the occipital and marginal sinuses seemed to be markedly developed. Evacuation of the subcortical hematoma was carried out. Histologically, it was a mixed hematoma in acute and chronic stages without any carcinoma component or vascular malformation. Postoperative course was uneventful, and the patient was returned to the division of surgery in order to follow up the cancer 2 weeks after operation. Angiography 4 months after operation showed almost no recanalization in the left transverse sinus. Further, development of the collateral flow and the double occipital sinus was opacified. Because the coagulation system is often activated by the presence of cancer, it is important to distinguish intracerebral hemorrhage due to sinus thrombosis from intratumorous hemorrhage within a metastatic tumor.

Adenocarcinoma↗

PubMed1993

Accelerated evolution of Trimeresurus flavoviridis venom gland phospholipase A2 isozymes.

Six Trimeresurus flavoviridis (Habu snake) venom gland phospholipase A2 (PLA2) isozyme genes were found to consist of four exons and three introns and to encode proteins of 138 amino acid residues, including the signal sequence of 16 amino acid residues. Comparison of the nucleotide sequences showed that the introns are much more homologous than the protein-coding regions of exons except for the signal peptide-coding region of the first exon. The numbers of nucleotide substitutions per site (KN) for introns are approximately one-fourth of the numbers of nucleotide substitutions per synonymous site (KS) for the protein-coding regions, indicating that the introns are unusually conserved. The absence of an apparent functional role for the introns suggests that the protein-coding regions, except for the signal peptide-coding domains, have evolved at greater substitution rates than introns. The fact that the numbers of nucleotide substitutions per nonsynonymous site (KA) are close to or larger than KS values for relevant pairs of genes revealed that Darwinian-type accelerated substitutions have occurred in the protein-coding regions or exons. This is compatible with the presence of PLA2 species with diverse physiological activities in the venom.

Amino Acid Sequence↗

PubMed1993

Calcium entry blocking activities of MPC-1304 and of its enantiomers and metabolites.

The Ca2+ entry blocking effects of MPC-1304, a new Ca2+ entry blocker of the 1,4-dihydropyridine type, and of its (S) and (R) enantiomers and metabolites were examined on Ca(2+)-induced contractions in isolated rabbit arteries. The Ca2+ entry blocking activity of the (S) enantiomer of MPC-1304 was approximately 150 times greater than that of its (R) enantiomer. Likewise, the antihypertensive effect of the (S) enantiomer was twice as great as that of MPC-1304 (racemate) in conscious spontaneously hypertensive rats, while the (R) enantiomer was ineffective. Thus, most of the pharmacological activity of MPC-1304 resides in its (S) configuration. The main metabolic products of MPC-1304 also inhibited the Ca(2+)-induced contraction in the isolated vascular smooth muscles. These active metabolites showed a stereoselectivity similar to that of MPC-1304 for Ca2+ entry blocking activity, and may contribute to the potent antihypertensive action of MPC-1304.

Animals↗

PubMed1993

Purification, sequencing and characterization of single amino acid-substituted phospholipase A2 isozymes from Trimeresurus gramineus (green habu snake) venom.

Two phospholipases A2 named PLA2-III and IV were newly isolated from Trimeresurus gramineus (green habu snake) venom in addition to PLA2-I and II reported previously [ODA et al. (1991) Toxicon 29, 157; Fukagawa et al. (1992) Toxicon 30, 133]. Their isoelectric points were determined to be about 4.5. PLA2-III and IV exhibited almost unchanged lipolytic activity toward egg-yolk when compared with PLA2-I. The amino acid sequences were determined by sequencing the native proteins and the peptides produced by enzymatic (Achromobacter protease I and clostripain) and chemical (hydroxylamine) cleavages of the S-carboxamidomethylated derivative of the proteins. Both proteins consisted of 122 amino acid residues. When compared with PLA2-I, PLA2-III showed only a single amino acid substitution at the N-terminal position; namely from His to Asn. PLA2-IV also showed a single substitution from Ala to Asp at position 72. It was inferred that these amino acid substitutions between PLA2-I and PLA2-III or IV are due to the single base substitution at the corresponding codons of genes, which might be preserved independently. The unique presence of Phe at position 28, where Tyr is commonly located and assumed to be a part of the Ca(2+)-binding loop, was conserved in both PLA2-III and IV as in PLA2-I. There was no significant difference in the dissociation constants (4.3-5.2 x 10(-4) M) for Ca2+ between these PLA2S and Tyr-28-containing PLA2S. These results suggested that the p-hydroxy group of Try-28 does not play a crucial role in binding of PLA2S to Ca2+.

Amino Acid Sequence↗

PubMed1993

Vertebral bone metastasis of small cell carcinoma of lung in a diabetic patient, initially diagnosed as pyogenic vertebral osteomyelitis.

A 40-year-old man with a 3-year history of uncontrolled NIDDM, 2-pack/month cigarette smoking habit and alcohol abuse, was admitted to our university hospital. He presented with severe back pain, persistent cough and fever. A left lung infiltrate was noted on chest X-ray film. Staphylococcus aureus was isolated from arterial blood. Thoracic bone destruction with pleural mass lesion confirmed by computed tomography (CT) and magnetic resonance image (MRI). These findings mislead our diagnosis to pyogenic osteomyelitis associated with NIDDM. An absence of marked clinical and roentgenological improvement after antibiotic therapy and strict glycemic control with insulin was noted. This suggested to us the need for needle biopsy of the osteolytic and mass lesions confirmed by imaging techniques. This resulted in making the diagnosis of metastasis of small cell carcinoma from the left lung. The correlation between NIDDM and pulmonary small cell carcinoma possibly induced by genetic abnormality remains to be resolved. By making the most of imaging techniques and needle biopsy, the possibility of pulmonary small cell carcinoma complicating NIDDM can be appropriately evaluated.

Adult↗

PubMed1993

Ossifying fibromyxoid tumor of soft parts: a case report.

A case of ossifying fibromyxoid tumor of soft tissue parts in the presacral region, which developed in a 46-year-old Japanese man is reported. The enucleated tumor was an encapsulated, elastic, hard mass measuring 2.5 x 2.2 x 1.4 cm. Microscopically, the tumor was characterized by foci of round to polygonal cells dispersed in a fibromyxoid matrix, containing varying amounts of collagen and osteoid tissue. At the marginal zone, the shell of bone and osteoid tissue with calcification separated the tumor from the surrounding tissues. Our patient is showing no evidence of recurrence after a one-year follow-up period. The findings are compatible with those proposed for ossifying fibromyxoid tumor of soft parts by Enzinger et al. in 1989. This tumor should be differentiated from cartilaginous, osteogenic and neural tumors.

Fibroma↗

PubMed1992

Unusually high conservation of untranslated sequences in cDNAs for Trimeresurus flavoviridis phospholipase A2 isozymes.

As a step toward understanding the structure and function of phospholipases A2 (PLA2s), we isolated and sequenced several cDNAs encoding Trimeresurus flavoviridis venom PLA2 isozymes including two [Lys49]PLA2s called basic proteins I and II, [Thr37]PLA2, and PLX'-PLA2. Comparison of the nucleotide sequences of these cDNAs with the previously isolated [Asp49]PLA2 cDNA revealed some interesting findings from the viewpoint of evolution. First, the homologies of the 5' and 3' untranslated regions (98% and 89%, respectively) were much higher than that of the protein-coding regions (67%). The predicted secondary structure showed the characteristic stem-loop structures for both the untranslated regions of the mRNAs, suggesting that these regions play some functional role(s) in translation or stability of mRNAs. Second, base substitutions appeared to have occurred at similar rates for the three positions of codons among these PLA2s. The results are discussed in terms of evolution of PLA2s. Northern blot analysis showed that these PLA2s are specific to venom gland.

Amino Acid Sequence↗

PubMed1992

Validity of putative calcium binding loops of photoprotein aequorin.

Three peptides containing the putative Ca2+ binding loops, I, II and III, respectively, of a photoprotein, aequorin, from jellyfish Aequorea victoria were synthesized by a solid-phase procedure. The peptides bound Ca2+ with dissociation constants of 10(-3) to 10(-4) M, providing evidence for the assumption that Ca2+ binding loops are actually responsible for the binding of Ca2+. When the highly conserved 6th glycine residue in the 12-residue loops was replaced by arginine, no large effect was observed on Ca2+ binding. Exposure to a hydrophobic environment and the binding of Ca2+ brought about conformational changes to the peptides.

Aequorin↗

PubMed1992

Evaluation of retinal integrity in eyes with retained intraocular metallic foreign body by ERG and EOG.

In three eyes with a retained intraocular metallic foreign body, the neural retina and retinal pigment epithelial (RPE) integrity were evaluated by means of ERG (a-wave, b-wave, oscillatory potentials) and non-photic EOG responses from the RPE (hyperosmolarity response, Diamox response, bicarbonate response). All three cases were judged in an early stage of retinal impairment on the basis of a well-preserved or supernormal b-wave amplitude and showed good postoperative prognosis. Out of three non-photic responses from the RPE, only the bicarbonate response was preoperatively reduced in two out of the three eyes.

Adult↗

PubMed1992

Sequence determination and characterization of a phospholipase A2 isozyme from Trimeresurus gramineus (green habu snake) venom.

In addition to phospholipase A2-I (PLA2-I) reported previously (ODA et al., 1991, Toxicon 29, 157), a new PLA2 named PLA2-II was isolated from Trimeresurus gramineus (green habu snake) venom, and its amino acid sequence was determined by sequencing the native protein and the peptides produced by enzymatic (Achromobacter protease I and clostripain) cleavages of the carboxamidomethylated derivative of the protein. The protein consisted of 122 amino acid residues and His-47, Asp-48, and Asp-98 which have been assumed to be essential for PLA2 activity were conserved. Its sequence similarity to PLA2-I was 79%, with 26 residual differences. In contrast to the unique presence of Phe-28 in PLA2-I, PLA2-II contains Tyr-28 as seen in most of other PLA2s. There was no significant difference between the dissociation constants of PLA2-I and PLA2-II for Ca2+. Secondary structure compositions of PLA2-II were similar to those of PLA2-I and Crotalus atrox PLA2. A striking difference was found between these isozymes in contractile activity of isolated smooth muscle preparation of guinea-pig ileum. PLA2-II was over ten times more potent than PLA2-I, although its lipolytic activity toward egg-yolk was even slightly weaker (73%) than that of PLA2-I. The difference in contractile activities of PLA2-I and PLA2-II could be assumed to be due to discriminative lipid recognition brought about by different amino acid residues at the 58th position (Asp for PLA2-I and Asn for PLA2-II).

Alcaligenes↗

PubMed1992

[Coexistence of intracranial and spinal cavernous angiomas: case report].

A case of a 43-year-old man with coexistence of intracranial and spinal cavernous angiomas is presented. The patient had a 2-year history of severe back pain incurred by neck flexion, and he became aware of weakness of the right lower extremity and paresthesia of the left lower extremity. Neurological examinations at the time of the first admission demonstrated incomplete Brown-Séquard syndrome. Myelograph, myelo-CT and contrast enhanced CT showed an intramedullary mass at the Th3-Th5 level. The patient received laminectomy with total removal of the lesion. Pathological diagnosis was cavernous angioma. Six years later, the patient complained of subacute weakness and numbness of the left upper extremity. Head CT demonstrated a high density lesion of about 2cm in diameter in the right frontal lobe. MRI showed a mixed signal intensity lesion with a marked low-intensity rim in the same area. Total extirpation of the lesion was performed. Pathological diagnosis of the intracerebral lesion was also cavernous angioma. Intramedullary cavernous angioma is very rare. Furthermore, bifocal cavernous angiomas involving both the spinal cord and the brain are extremely rare, and, only 5 cases have been reported in the literature. To our knowledge, this is the first case diagnosed by surgical specimens of coexisting intramedullary and intracerebral lesions.

Adult↗

PubMed1991

The posterior inferior cerebellar artery originating from the internal carotid artery, associated with multiple aneurysms.

We report the rare case of ipsilateral posterior inferior cerebellar artery originating from the carotid artery, and associated with multiple concurrent aneurysms. This is the 23rd reported case of carotid-cerebellar anastomosis and the first case with three concurrent aneurysms reported in the literature. Of the 23 cases, 6 had single aneurysms, 2 had double aneurysms and the present case had triple aneurysms.

Adult↗

PubMed1991

Amino acid sequence of a phospholipase A2 from the venom of Trimeresurus gramineus (green habu snake).

Two phospholipases A2, named phospholipases A2-I and A2-II, were purified to homogeneity from the venom of Trimeresurus gramineus (green habu snake). The complete amino acid sequence of phospholipase A2-I was determined by sequencing the native protein and the peptides produced by enzymatic (Achromobacter protease I, clostripain, and chymotrypsin) and chemical (hydroxylamine) cleavages of the S-pyridylethylated derivative of the protein. The protein consisted of 122 amino acid residues and was similar in sequence to phospholipases A2 from the venoms of crotalid snakes which belong to the category of Group II. A most striking feature of this protein is that tyrosine at the 28th position which is common in phospholipases A2 and is assumed to be a part of the Ca2(+)-binding loop is replaced by phenylalanine. Such replacement is the first finding in Group II phospholipases A2. Secondary structure compositions of phospholipase A2-I are similar to those of Crotalus atrox phospholipase A2. No appreciable Ca2(+)-induced difference spectrum was observed, due probably to the absence of the effective chromophoric groups in the neighborhood of the Ca2+ binding site although Ca2+ is bound with affinity similar to that for T. flavoviridis phospholipase A2.

Amino Acid Sequence↗

PubMed1991

Contributions of genetic studies to clinical psychiatry.

Recent twin and family studies have demonstrated a genetic factor in Gilles de la Tourette syndrome, some cases of infantile autism, enuresis, specific reading disability, sleepwalking, night terrors, common fears and anxiety. Family studies have been used to elucidate the nosological relationship of psychiatric disorders; e.g. anorexia nervosa (to affective disorder), Gilles de la Tourette syndrome, and sleeptalking. Advances in biochemical genetics and in enzyme polymorphisms suggest that there are wide individual variations in the adverse effects of drugs and that dosage should be tailored to the individual patient. Recently molecular genetic methods have been introduced to psychiatry, but a major breakthrough in this field appears to be still years away.

Adolescent↗

PubMed1991

Fluvirucins A1, A2, B1, B2, B3, B4 and B5, new antibiotics active against influenza A virus. IV. Taxonomy on the producing organisms.

The morphology, chemotaxonomy, and cultural and physiological characteristics were examined on the five strains of actinomycetes which produce antiviral antibiotics, fluvirucin congeners. All strains have meso-2,6-diaminopimelic acid in the cell wall. Four strains, Q464-31, L407-5, R359-5 and R516-16, belong to the maduromycetes since they have madurose in the whole cell. The remaining one strain, R869-90, has rhamnose but no madurose, and is a nocardioform actinomycete. These five strains were classified and designated as follows: Strain Q464-31 (fluvirucin A1 producer): Microtetraspora tyrrhenii sp. nov. (Actinomadura pusilla group). Strain L407-5 (fluvirucin B2 producer): A maduromycete. Strain R359-5 (fluvirucin B1 producer): Microtetraspora pusilla (Actinomadura pusilla group). Strain R869-90 (fluvirucin A2 producer): Saccharothrix mutabilis. Strain R516-16 (fluvirucins B2, B3, B4 and B5 producer): A maduromycete.

Actinomyces↗