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Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 541 records · Page 30Linked to original sources
PubMed1994

Morphometry of the kidney in rat pups from uninephrectomized mothers.

BACKGROUND: The present study was designed to explore whether maternal renal dysfunction affects fetal kidney development and if the effects are lasting during the postnatal development. METHODS: Kidneys of 1-day-old and 6-week-old pups from mothers which were uninephrectomized on day 5 of gestation were studied. RESULTS: One day after birth, both the number of immature glomeruli and average volume of mature glomeruli of the neonates from uninephrectomized mothers were significantly larger than those from sham-operated mothers. Six weeks after birth, no significant differences in parameters of the kidney were observed between the pups from uninephrectomized and those from sham-operated mothers. Furthermore, blood urea nitrogen (BUN) concentration in adult female rats was determined at various days after uninephrectomy. BUN concentration in uninephrectomized rats was significantly higher than that in sham-operated ones. CONCLUSIONS: These results suggest that the fetal kidney development is accelerated by the elevated BUN level following maternal uninephrectomy and that the renotropic activity does not last during the postnatal developmental period.

Animals↗
PubMed1994

A unique murine CD43 epitope Lp-3: distinct distribution from another CD43 epitope S7.

In foregoing studies, we found a unique B cell differentiation antigen Lp-3 which is expressed on pre-B and premature B cells in the bone marrow, but is negative on bone marrow mature B cells and peripheral resting B cells. Nonetheless, Lp-3 was clearly positive on the majority of CD5 B(B1) cells. When we examined the biochemical nature and partial amino acid sequences of purified 132-kDa Lp-3 molecules and the nucleotide sequence of the cDNA clones, we found that Lp-3 is an epitope of CD43. Thus, the monoclonal antibody (mAb) Lp-3 may be the first mAb to murine CD43 defined by primary target structure analysis. Comparison of tissue distribution of Lp-3 and S7, an epitope previously suggested to associate with murine CD43, showed that they were similarly distributed on thymocytes, peripheral B and T cells, granulocytes, and platelets. In the bone marrow, while both Lp-3 and S7 were negative on mature B cells, the former was positive on all B lineage cells at an early ontogeny and the latter was positive only on the minor population of pre-B cells and pro-B cells. Lp-3 and S7 epitopes also showed different distributions on basement membranes of renal glomerulus, bronchus, and endometrium, lining cells of choroid plexus and muscular cells of arterioles in a variety of tissues. As CD43 has various isoforms generated by different degrees of glycosylation of the common core peptide, it is likely that Lp-3 and S7 are associated with different CD43 isoforms.

Amino Acid Sequence↗
PubMed1994

Mitochondrial changes in acute myopathy after treatment of respiratory failure with mechanical ventilation (acute relaxant-steroid myopathy).

A case of acute myopathy was observed in the course of treatment of respiratory failure with mechanical ventilation combined with prolonged neuromuscular blockade and administration of corticosteroids. A muscle biopsy revealed degeneration of muscle fibres. Electron microscopy showed loss of thick filaments as well as nemaline rods, vacuoles and cytoplasmic bodies. The mitochondria were increased in number, many harbouring paracrystalline inclusions, which were hitherto unknown in this condition.

Combined Modality Therapy↗
PubMed1994

Ultracytochemical demonstration of ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (Na-K ATPase) activity in cat facial nerve.

Ouabain-sensitive, K(+)-dependent, p-nitrophenylphosphatase (K-NPPase) is the second dephosphorylative property of the Na-K ATPase complex. Localization of its activity in the horizontal portion of the facial nerve in 11 normal cats was studied ultracytochemically using a cerium-based method. The fine granular reaction product of the K-NPPase activity was observed on the cytoplasmic side of the axolemma of the axon cylinder. Enzyme activity was also detected on the cytoplasmic side of the plasma membrane of Schmidt-Lanterman incisures and nodes of Ranvier. No reaction product was detected on the periaxonal and outermost plasma membrane of Schwann cells and in the myelin sheath. In control tissue samples, enzyme activity was almost completely inhibited by 10 mM ouabain, and no reaction was noted in medium without K+. The present findings indicate that localization of Na-K ATPase in the cat facial nerve simulates that of other peripheral and cranial nerves.

4-Nitrophenylphosphatase↗
PubMed1994

Effects of prophylactic intrathecal administrations of nicardipine on vasospasm in patients with severe aneurysmal subarachnoid haemorrhage.

Calcium antagonists are currently most widely used for chronic cerebral vasospasm after aneurysmal subarachnoid haemorrhage (SAH). However, the vasodilatory effects of systemically administered calcium antagonists can be limited secondary to hypotension. We previously compared intrathecal and intravenous routes of administration of nicardipine. Intrathecal administration of nicardipine significantly dilated spastic basilar arteries on day 7 in a two-haemorrhage canine model of vasospasm. In the present communication, the effects of prophylactic, serial administration of intrathecal nicardipine on vasospasm was examined in 50 patients. Patients were classified as Fisher SAH group 3 and all had their aneurysms clipped within 3 days of SAH. Following placement of a cisternal drain, 2 mg of nicardipine was injected, three times each day for an average of 10 days. The control group consisted of 91 similar patients with cisternal drainage not treated with nicardipine. Intrathecal administration of nicardipine decreased the incidence of symptomatic vasospasm by 26%, angiographic vasospasm by 20% and increased good clinical outcome at one month after the haemorrhage by 15%. Postoperative angiograms revealed that patients in the nicardipine group showed less vasospasm of major cerebral arteries, near the tip of a drain in the basal cistern, but vasospasm in the A2 and M2 segments was not decreased. Radio-isotope cisternography suggested that nicardipine might not reach the subarachnoid space around A2 and M2 segments. Nine patients complained of headache probably secondary to nicardipine induced vasodilation. Two patients suffered from meningitis, both were successfully treated. Intrathecal administration nicardipine appears to be effective in the treatment of vasospasm, but side effects were significant.

Adult↗
PubMed1994

A novel in vitro assay system for transendothelial tumor cell invasion: significance of E-selectin and alpha 3 integrin in the transendothelial invasion by HT1080 fibrosarcoma cells.

The interaction of tumor cells with endothelial cells is a key event in tumor metastasis. We established an in vitro invasion assay system, in which the invasion of tumor cells after interaction with endothelial cells can be examined. Two chamber culture wells separated by porous membrane were used. Human umbilical vein endothelial cells (HUVEC) were placed on porous membranes coated with matrix components. The invasion by HT1080 fibrosarcoma cells was determined in this system by counting the number of cells that moved through the membranes from upper to lower chambers. HUVEC cells did not migrate through the membranes as judged by the staining with UEA-I. Observation by scanning electron microscopy revealed that HT1080 cells bound to HUVEC surfaces and migrated underneath the HUVEC monolayer. Effects of antibodies specific for cell surface adhesion molecules on the migration of HT1080 cells were examined. Invasion of uncoated membranes and membranes coated with HUVEC cells was compared. Antibody against E-selectin significantly suppressed an increase of HT1080 cell invasion of HUVEC monolayers stimulated by IL-1 beta or TNF alpha. Antibody against integrin alpha 3 subunit remarkably inhibited the invasion of HUVEC cell-coated membranes, suggesting that integrins with the alpha 3 subunit may play an important role in the transendothelial invasion by HT1080 cells.

Cell Adhesion Molecules↗
PubMed1994

Genotoxic activities in vivo of cobaltous chloride and other metal chlorides as assayed in the Drosophila wing spot test.

A series of metal chlorides were subjected to the wing spot test of Drosophila melanogaster. In the test, larvae trans-heterozygous for the wing-hair mutations mwh and flr were orally treated at the third instar stage with a test compound and the wings were inspected at the adult stage for spots expressing phenotypes of the markers. CoCl2, MnCl2, MoCl3, NiCl2 and ZnCl2 were clearly effective in inducing spots with one or two mutant hairs (small spots). CoCl2 was clearly effective in inducing spots with three or more mutant hairs (large spots) as well. CrCl3, FeCl2 and FeCl3 were negative under the conditions used. Based on estimated frequencies of small spots induced at the LD50, the genotoxic effectiveness of the positive metal salts were ranked in a sequence of CoCl2 > ZnCl2 > MoCl3 > (MnCl2, NiCl2). Since CoCl2 did not induce large spots in the wings of the mwh/TM3 flies with a suppressed ability of mitotic crossing-over, the large spots induced by this compound in the mwh/flr system were ascertained as mutant clones due to mitotic crossing-overs.

Animals↗
PubMed1994

HIV type 1 infection of CD4+ T cells depends critically on basic amino acid residues in the V3 domain of envelope glycoprotein 120.

The third variable domain (V3 domain) of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 is a major determinant of phenotypic variability. The V3 domain of HIV-1 has many basic amino acid residues. Lymphocytotropic HIV-1 tends to have a V3 domain with a higher density of positive charge than does monocytotropic HIV-1. The importance of basic residues in the V3 domain for the HIV-1 infectivity, however, has not been well investigated. Here we show that mutation of basic amino acid residues at positions 303, 306, 309, 313, and 325 in the V3 domain of the lymphocytotropic isolate NL4-3 results in a dramatic elimination of both virus infectivity and syncytium-inducing ability. Three basic amino acid substitutions (at position 306, 309, and 313) induced a decrease in the binding ability of two kinds of neutralizing antibodies (NEA9284 and 0.5 beta) that recognize a different site in the V3 domain. This suggests that the basic residues play an important role in maintaining the tertiary structure of the V3 domain. Monocytotropism was not simply dependent on either decreased positive charge in the V3 domain of NL4-3 or on mutation of lysine to glutamate at position 320, which is a characteristic amino acid of monocytotropic HIV-1. These findings contribute to our understanding of the significance of basic residues on the function of envelope glycoprotein.

Amino Acid Sequence↗
PubMed1994

Inhibition of vasoactive amine induced contractions of vascular smooth muscle by hydrogen peroxide in rabbit aorta.

OBJECTIVE: The aims were to investigate the effects of H2O2 on arterial contractions induced by vasoactive amine agonists and a high concentration of potassium ions (high K+) in vitro and to explore the possible underlying mechanism(s) involved. METHODS: Isometric tension of rabbit isolated aortic strips was measured and the effects of pretreatment with H2O2 on contractions induced by phenylephrine and high K+ were compared. The effects of H2O2 on precontracted strips were determined in the presence and absence of the aortic endothelium and compared with those of acetylcholine. RESULTS: The tension developed in response to an agonist was expressed as a percentage of the contraction induced by high K+ (64.7 mM) superfusion. Pretreatment with 300 microM H2O2 reduced the mean phenylephrine (0.3 microM) induced contraction from 96.2(SEM 1.4) to 61.8(2.8)%; the effect was stable and reversed by washing out the H2O2. Hydrogen peroxide relaxed phenylphrine precontracted strips with and without endothelium but it showed no relaxant effect when the strips were precontracted by high K+, whereas acetylcholine (1 microM) induced transient relaxation of high K+ precontracted strips by 27.8(2.9)%. The relaxant effect of H2O2 was not affected by pretreatment with indomethacin (a cyclo-oxygenase inhibitor), desferrioxamine (a hydroxyl radical scavenger), or diphenylphenylenediamine (a lipophilic antioxidant). CONCLUSIONS: H2O2 inhibits vasoactive amine induced contractions of the vascular smooth muscle of rabbit aorta in vitro without affecting voltage dependent Ca2+ influx or contractile machinery. The mechanism responsible for its inhibitory effects may be related to impairments of the cellular signalling reactions initiated by the agonists.

Acetylcholine↗
PubMed1994

Cytochrome c electronic structure characterization toward the analysis of electron transfer mechanism.

Seventy-four kinds of cytochrome c sequences have been compared in order to determine the conserved residues and residues of which the characters are conserved. Twenty-three residues are invariant throughout all the aligned sequences, while the residues at 17 other positions share common characters. The prosthetic group as well as these conserved and character-conserved residues are considered to constitute a model molecule to elucidate the electron transfer process in cytochrome c. Their coordinates in the structure of tuna cytochrome c are extracted, and an extended Hückel molecular orbital calculation has been executed on this molecule. The examination of the shapes and the energy levels of the resulting MOs has suggested that three nearly degenerate HOMOs might play an important role in the electron transfer. These HOMOs are exposed to the protein surface around the heme, Cys-17, and Phe-82. A delocalized electron system developing in these regions is proposed to be the electron transfer pathway of cytochrome c.

Amino Acid Sequence↗
PubMed1994

Association between a cytochrome P450 CYPIA1 genotype and incidence of lung cancer.

We analysed 267 samples from patients with lung cancer and 54 samples from patients with pancreatic cancer and classified them into three types (A, B and C) based on their P450CYPIA1 genotypes. This was performed by restriction fragment length polymorphism (RFLP) analysis of DNA (that had been amplified) using the polymerase chain reaction (PCR). Our results reconfirmed previous studies with RFLP analyses by revealing significantly higher frequencies of C type in lung cancer patients, particularly light smokers with squamous cell carcinoma (p < 0.001). Also when we compared the appearance rate of P450CYPIA1 genotype in lung cancer patients between metastasis group and no metastasis group, lymph node or distant metastasis was more frequently observed among the patients of squamous cell carcinoma, especially the light smoking group, with C genotypes (p < 0.05). These results suggested that this genotype is not only associated with the etiology of lung cancer but also with the status of metastasis. Furthermore, genotyping could be useful in predicting the incidence of lung cancer in the smokers and the general population as well as the prognosis of individuals who develop this disease.

Aged↗
PubMed1994

Detection of DNA of causative agent of spotted fever group rickettsiosis in Japan from the patient's blood sample by polymerase chain reaction.

The polymerase chain reaction (PCR) was applied for the etiological diagnosis of spotted fever group (SFG) rickettsiosis in Japan. Nucleotide primers derived from the 17-kDa antigen gene of Rickettsia rickettsii primed a rickettsia-specific 246-base-pair product for all of the Katayama, Abe, Misaka and Kojima strains, which we had isolated previously. Moreover, we were able to detect the same product by PCR amplification from the peripheral blood of a patient in the acute stage of the illness. The PCR method is considered to be useful for rapid etiological diagnosis of SFG rickettsiosis in Japan.

Animals↗
PubMed1994

Purification and characterization of gonadotropin I and II from pituitary glands of tuna (Thunnus obesus)

The duality of teleost pituitary gonadotropins was established in an advanced marine fish, the tuna (Thunnus obesus). Two different molecular forms of gonadotropins, designated tGTH I and tGTH II, were isolated from an alcoholic extract of pituitary glands following ion-exchange chromatography and reversed-phase HPLC. Both tGTH I and tGTH II stimulated estradiol-17 beta and testosterone production in tuna ovarian follicles in vitro, although responses to tGTH II were significantly greater than those to tGTH I. Each gonadotropin consisted of alpha- and beta-subunits. tGTH I was stable in acidic conditions, whereas tGTH II dissociated into two subunits after acid treatment. Alpha subunits of tGTH I and tGTH II had identical amino acid sequences of 94 amino acid residues. The tGTH I beta and tGTH II beta consisted of 102 and 115 amino acid residues, respectively, and showed 35% sequence identity. tGTH I beta is structurally more similar to salmon GTH I beta than to salmon GTH II beta, whereas tGTH II beta is more similar to salmon GTH II beta. Thus it is evident that the tuna pituitary gland produces two chemically distinct gonadotropins.

Amino Acid Sequence↗
PubMed1994

Long-term follow-up study of 10 adolescent patients with sleep-wake schedule disorders.

Therapeutic trials for sleep-wake schedule disorders have been described, but a long-term follow-up of adolescents with such disorders have not previously been reported. We investigated 10 adolescents with sleep-wake schedule disorders who had formerly received intensive treatment. The investigation was carried out with detailed questionnaires about current sleep conditions and social state. The follow-ups were obtained from 1.2 to 11.2 years after the initial treatment. Three cases have remitted, and six have improved in illness severity. All patients showed improvement in social adaptation. Improvement in the social adaptation level was greater than improvement in the illness severity level. More cases should be studied to learn what factors influence the prognosis of these disorders.

Adolescent↗
PubMed1994

Cultural anthropology approach to psychopathology of Muslim murderer.

We report a case involving a 31-year-old Islamic male who murdered his associate under particular circumstances. We took the opportunity to test psychiatrically this man who has been diagnosed in his mother country as a schizophrenic. He came to Japan and was working as a laborer. He is an earnest practicing Muslim. We took an interest in this case because of his bizarre behavior previous to the actual crime. We are interested in the actual method of the murder in relation to Mr. A's cultural and religious background. We demonstrated the significance of the religious cultural knowledge relative to the indigenous ritual for expelling satan and the Islamic pilgrimage to Mekka (Hajj). We conclude that a cultural anthropological and religious viewpoint is necessary in objectively understanding the sources of suffering in patients with mental illness who are from foreign countries.

Adult↗