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H Tatsumi

Publications and source records attributed to H Tatsumi.

At least 19 recordsLinked to original sources
PubMed1992

Molecular cloning and expression in Escherichia coli of a cDNA clone encoding luciferase of a firefly, Luciola lateralis.

We have cloned a cDNA encoding Luciola lateralis (a common firefly in Japan) luciferase from a cDNA library of lantern poly(A)+ RNA, using a cDNA of L. cruciata (another common firefly in Japan) luciferase as a probe. The primary structure of L. lateralis luciferase deduced from the nucleotide sequence was shown to consist of 548 amino acids with a molecular weight of 60,132. Sequence comparison indicates that L. lateralis luciferase has significant sequence identity (94%) to L. cruciata luciferase, and that it has less sequence similarity (67%) to Photinus pyralis (a North American firefly) luciferase. The isolated cDNA clone, when introduced into Escherichia coli, directed the synthesis of enzymatically active luciferase under the control of the lacZ promoter.

Amino Acid Sequence↗
PubMed1992

Purification and characterization of luciferases from fireflies, Luciola cruciata and Luciola lateralis.

Luciferases of Luciola cruciata and Luciola lateralis, LcL and LlL, were purified to homogeneity by ammonium sulfate precipitation, gel-filtration column chromatography, and hydroxyapatite HPLC. The molecular masses of the enzymes determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were both 62 kDa, almost identical to that of Photinus pyralis (PpL). LcL was found to be similar to PpL in thermal stability, pH stability, and the wavelength of maximum light intensity. LlL was superior to LcL and PpL in thermal and pH stability, and the reaction catalyzed by LlL emits green light with a peak intensity at 552 nm, which is 10 nm shorter in wavelength than those of PpL and LcL.

Animals↗
PubMed1992

High expression of manganese superoxide dismutase in 7,12-dimethylbenz[a]anthracene-induced ovarian cancer and increased serum levels in the tumor-bearing rats.

Manganese superoxide dismutase (Mn-SOD) is strongly expressed in human ovarian cancer, and the serum level of the enzyme is a useful marker for the diagnosis and monitoring of human ovarian cancer. In the present study we found that Mn-SOD was highly expressed in primary and transplanted ovarian cancers in rats induced by 7,12-dimethylbenz[a]anthracene (DMBA), as judged by enzyme-linked immunosorbent assay as well as by Northern blot analysis. The serum levels of Mn-SOD in the tumor-bearing rats were also higher than those in control rats. The antibody strongly reacted with rat ovarian carcinoma tissues. These data suggest that DMBA-induced ovarian cancer in rats is a good experimental model for human ovarian cancer, and that Mn-SOD is also a good marker for disease in the animal model.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1992

Distribution of manganese superoxide dismutase in rat stomach: application of Triton X-100 and suppression of endogenous streptavidin binding activity.

The distribution of rat manganese superoxide dismutase (Mn-SOD) was immunohistochemically investigated in the rat stomach with a specific polyclonal antibody and a labeled streptavidin-biotin immunoglobulin detection system in cryosections. Parietal cells in the stomach were intensely stained, whereas the other epithelial cells in the gastric gland and pit exhibited only slight staining. Rapid-freezing and freeze-substitution immunoelectron microscopy revealed that Mn-SOD in parietal cells was mainly localized in mitochondria. Therefore, the large amount of Mn-SOD in parietal cells is due to the abundant mitochondria, in which Mn-SOD is considered to play important roles in protecting the ion pump and the cell itself from superoxide insult. Application of Triton X-100, cryosectioning, and the streptavidin-biotin system are needed to distinctly visualize Mn-SOD with our antibody. Treatment of the cryosections with Triton X-100 enhanced not only the immunoreactivity but also the false-positive staining, which showed a similar distribution pattern to that of Mn-SOD and thus made it difficult to determine the localization. The most plausible cause of the false-positive staining is thought to be endogenous biotin in the stomach, which survives paraformaldehyde fixation and is revealed by Triton X-100 treatment. Suppression of the endogenous streptavidin binding activity is important when cryosections, the streptavidin-biotin system, and Triton X-100 are employed.

Animals↗
PubMed1992

Cardiovascular effects of the new generation calcium antagonist 3-pyridine carboxylic acid 5-[(cyclopropylamino)carbonyl]-1,4-dihydro-2,6-dimethyl-4-(2-nitropheny l) octyl ester.

The cardiovascular effects of 3-pyridine carboxylic acid 5-[(cyclopropylamino)carbonyl]-1,4-dihydro-2,6-dimethyl-4-(2-nitro phenyl) oxtyl ester (NP-252, CAS 132031-81-3) were examined in anesthetized closed- or open-chest dogs and Langendorff perfused rabbit hearts, and compared with those of nifedipine (NF) and nicardipine (NC). In anesthetized closed- and open-chest dogs, NP-252 (i.v.) selectively increased vertebral and coronary blood flow with a fall in mean blood pressure (MBP). These effects were nearly equipotent with those of NF and NC, but more durable. A similar effect was obtained by intraduodenal administration of NP-252. Also, NP-252 (i.v.) decreased MBP, total peripheral resistance (TPR), left ventricular pressure and dLVP/dtmax while cardiac output (CO) and stroke volume (SV) increased without apparent changes in heart rate and myocardial contractility index. Decreases in MBP and TPR by NP-252 were equipotent with NF and NC, whereas increases in CO and SV were more potent than those of the two drugs. These actions of NP-252 were longer than those of the reference agents. Further, in perfused rabbit hearts, NO-252 increased coronary perfusion flow (CPF), accompanying a slight negative inotropy. Its effect in CPF was equipotent with NF and 2 times less than that of NC, however the duration was much longer than those of the reference drugs. On the other hand, the negative inotropic effect of NP-252 was less than NF, but greater than that of NC. In the preparations controlled by pacing, NP-252 and NF lengthened atrio-His bundle conduction time, without affecting His bundle-ventricular conduction time. Lengthening effect of NP-252 was about 4 times less than that of NF. These results suggest that NP-252 acts more selectively on vascular smooth muscle than cardiac muscle, and has almost equipotent but markedly longer vasodilating actions as compared to NF and NC. It may be expected that NP-252 is a new generation of tissue specific and long acting Ca2+ antagonist.

Anesthesia↗
PubMed1991

Pharmacological characteristics of NP-252, a new dihydropyridine slow Ca2+ channel blocker, in isolated rabbit vascular smooth muscle and guinea pig myocardium: vascular selectivity.

NP-252, a new dihydropyridine derivative, and nifedipine non-competitively inhibited contractile responses to KCl and responses to Ca2+ in Ca(2+)-free medium containing KCl in rabbit aorta and renal, mesenteric, coronary and basilar arteries, mesenteric veins and vena cava. The effects of NP-252 in these smaller arteries and veins were much greater than those in aorta. However, a similar differential selectivity was not seen with nifedipine. In aorta, only NP-252 reduced total La3+ resistant 45Ca binding. However, the increases in bound 45Ca at La3+ resistant sites and 45Ca unidirectional influx due to KCl were inhibited by both NP-252 and nifedipine. The displacement of [3H]nitrendipine binding to rabbit aorta was monophasic for both NP-252 and nifedipine. In guinea-pig papillary muscles, NP-252 (greater than 10(-7) M) slightly decreased action potential duration, developed tension and slow action potentials. The cardiac effects of NP-252 were much less prominent than those of nifedipine. These results indicate that NP-252 inhibits voltage-operated Ca2+ channels in small arteries and veins much more effectively than those in aorta, and this tissue selectivity is more apparent for NP-252 than nifedipine.

Action Potentials↗
PubMed1991

Cloning and expression in yeast of a cDNA clone encoding Aspergillus oryzae neutral protease II, a unique metalloprotease.

The neutral protease II (NpII) from Aspergillus oryzae is a zinc-containing metalloprotease with some unique properties. To elucidate its structure, we isolated a full-length cDNA clone for NpII. Sequence analysis reveals that NpII has a prepro region consisting of 175 amino acids preceding the mature region, which consists of 177 amino acids. As compared with other microbial metalloproteases, NpII is found to be unique in that it shares only a limited homology with them around two zinc ligand His residues and that the positions of the other zinc ligand (Glu) and the active site (His) cannot be established by homology. When a plasmid designed to express the prepro NpII cDNA was introduced into Saccharomyces cerevisiae and the transformant was cultured in YPD medium (2% glucose, 2% polypeptone, 1% yeast extract), it secreted a proNpII. However, in a culture of the same medium containing 0.2 mM ZnCl2, it secreted a mature NpII with a specific activity and N-terminus identical to those of native NpII. This observation suggests that either an autoproteolytic activity or a yeast protease effected the processing.

Amino Acid Sequence↗
PubMed1991

Design and synthesis of antitumor compounds based on the cytotoxic diterpenoids from the genus Rabdosia.

Two active sites responsible for antitumor activity, an oxirane ring and an alpha-methylene-cyclopentanone moiety, have been extracted from studies on the structure-activity relationship of the cytotoxic diterpenoids isolated from Rabdosia shikokiana. Series of the simplified cyclopentanone derivatives containing both of the two active sites in the molecule have been synthesized and evaluated for cytotoxicity against P 388 cells. The compounds possessing both of two active sites displayed cytotoxicity at a concentration of 1 microgram/ml, while those possessing a single active site showed no activity.

Animals↗
PubMed1991

Post-embedding immuno-electron microscopy with rapid freezing and freeze-substitution techniques for the localization of manganese superoxide dismutase.

Dehydration of specimens with ethanol or acetone makes it impossible to detect manganese superoxide dismutase (Mn-SOD) by immunohistochemistry. To circumvent obstacles and demonstrate localization by post-embedding immuno-electron microscopy, a rapid freezing and freeze-substitution technique was employed using Lowicryl K4M embedding medium. This was effective enough to allow the specific observation of immunogold particles for Mn-SOD on the mitochondria of cardiac muscle cells and WI-38 cells (human normal fetal lung diploid cells). This method preserved the antigen-antibody binding activity of Mn-SOD even after dehydration. Therefore, rapid freezing and freeze-substitution is useful for post-embedding immuno-electron microscopy of Mn-SOD and can further be employed for other antigens previously difficult to detect by conventional methods.

Acrylic Resins↗
PubMed1991

Isolation and characterization of the alkaline protease gene of Aspergillus oryzae.

The genomic DNA for the alkaline protease (Alp) of the fungus Aspergillus oryzae was isolated using synthetic oligonucleotides as hydridization probes, and the complete nucleotide sequence was identified. The Alp gene is 1374 nucleotides long and contains three introns, one of which is in the pro region and two in the mature coding region. Sequences related to the TATA box (TATAAAT) and the CAAT box (CCAAAT) were found in the 5'-noncoding region. Primer extension analysis showed that three transcriptional start points are present.

Amino Acid Sequence↗
PubMed1990

Cloning and sequence analysis of mink growth hormone cDNA.

A cDNA clone for mink growth hormone (GH) was isolated from a mink pituitary cDNA library, employing a part of rat growth hormone cDNA sequence as a probe. According to the nucleotide sequence, mature mink GH consists of 190 amino acids with a calculated molecular weight of 21,720. The amino acid sequence homology between the mature region of mink GH and those of pig GH, rat GH, bovine GH and human GH was 98.4%, 93.7%, 89.0% and 66.7%, respectively.

Amino Acid Sequence↗
PubMed1990

A new method for three-dimensional reconstruction from serial sections by computer graphics using "meta-balls": reconstruction of "hepatoskeletal system" formed by Ito cells in the cod liver.

A new method is described for three-dimensional reconstruction from serial ultrathin sections, using "meta-balls" as a primitive of object modeling in computer graphics (CG). We take advantage of the meta-ball's blobbiness characteristic and its rendering system for reconstructing images. The two-dimensional outline data from serial sections are converted into three-dimensional meta-ball data with a graphic editor, "Metack," by which we can check the correctness of the data conversion. Then the converted data are visualized on a color display with a CG rendering software, "Tracy". This reconstruction method is applied in studying the spatial distribution of Ito cells (fat storing cells) in the cod liver in relation to the blood capillary. By observing the reconstructed images, we can easily understand the three-dimensional relationship between the Ito cells and the blood capillary. The Ito cells surround the blood capillary and extend their cytoplasmic processes into the inter-parenchymal space to make a well-developed network system. These findings would support a concept of "hepatoskeletal system" formed by Ito cells in the cod liver. Therefore, we think that the meta-ball reconstruction method is useful in morphological study.

Animals↗
PubMed1990

Hereditary motor and sensory neuropathy type 1 (HMSN1) associated with cranial neuropathy: an autopsy case report.

A family with hereditary motor and sensory neuropathy type 1 (HMSN1) is reported. Three patients suffered only pupillary abnormality, two patients showed Adie's syndrome and peripheral neuropathy, and one had cranial neuropathy. Adie's syndrome and severe peripheral neuropathy. Autopsy of the latter revealed reduction of myelinated nerve fibers in the trigeminal, facial and hypoglossal nerves. There was extensive degeneration of the posterior column of the spinal cord. At the anterior horns, loss of motor neurons was observed, particularly at the lumbar level. The anterior and posterior roots showed loss of myelinated fibers. HMSN1 is only rarely associated with cranial neuropathy, and this is probably the first autopsy-proved case.

Adie Syndrome↗
PubMed1990

Inhibition of calcium currents by noradrenaline, somatostatin and opioids in guinea-pig submucosal neurones.

1. Whole-cell recordings were made from submucosal neurones acutely dissociated from guinea-pigs. The actions of noradrenaline, somatostatin and [Met5]enkephalin on currents carried by calcium ions were studied. 2. On depolarization from a holding potential of -70 mV, an inward current activated at -40 mV, reached its peak amplitude at 10 mV and reversed to outward at 72 mV (with external calcium of 5 mM and internal caesium of 160 mM). 3. Cadmium, nickel and cobalt reversibly blocked the calcium current; concentrations causing 50% block were 2.5, 500 and 2000 microM respectively. The calcium current (holding at -70 or -30 mV) was reversibly blocked by omega-conotoxin (100 nM), and unaffected by Bay K 8644 (0.1-10 microM) and nifedipine (1 microM). Cadmium caused an outward shift in holding current at -30 mV, implying that there was a persistent inward calcium current at this potential. 4. Noradrenaline, somatostatin and [Met5]enkephalin decreased the calcium current. The maximal inhibition observed with any one agonist, or with a combination of two agonists, did not exceed 50%; concentrations giving half-maximal inhibition were 5.5 microM for noradrenaline, 4 nM for somatostatin and 1 microM for [Met5]enkephalin. The inhibition was independent of membrane potential. All three agonists also reduced the persistent calcium current at -30 mV. 5. Inhibition of the calcium current by noradrenaline occurred with a latency of not less than 175 ms; cadmium applied by the same method depressed the current within 5-45 ms. 6. Experiments with selective agonists and antagonists indicated that the receptor types involved in calcium current inhibition were alpha 2-adrenoceptors and delta-opioid receptors. Somatostatin acted at a distinct receptor. 7. Calcium currents were also inhibited by intracellular dialysis with guanosine 5'-O-(3-thiotriphosphate) (GTP-gamma-S). Agonists were ineffective in cells pre-treated with pertussis toxin, but their action was restored when purified GTP-binding proteins (Go or Gi) were included in the intracellular recording solution. 8. It is concluded that noradrenaline, somatostatin and [Met5]enkephalin act at their respective receptors on guinea-pig submucosal neurones to inhibit a voltage-dependent calcium current. Activation of the same receptors also increases a potassium conductance in these cells: in both cases a pertussis-sensitive G protein is involved.

Action Potentials↗
PubMed1990

Cation current activated by hyperpolarization (IH) in guinea pig enteric neurons.

Intracellular microelectrode and whole cell patch-clamp recordings were made from guinea pig enteric neurons in vitro. In most myenteric AH neurons (but not S neurons), step hyperpolarizations from the resting potential evoked an inward current (IH). IH peaked in approximately 400 ms (at 36 degrees C), was fully activated at -100 mV, and did not inactivate during 10 s. IH was associated with a conductance increase and reversed polarity at about -40 mV (by extrapolation). IH was reduced in low-sodium concentrations and increased when the concentration of extracellular potassium ions was increased. Cesium (2 mM) blocked IH in a voltage-dependent manner; this led to an increase in the amplitude of the spike after-hyperpolarization. Cobalt (2-4 mM) or barium (0.01-1 mM) did not alter IH. Only 12% of submucous plexus neurons showed IH and this subgroup included both S and AH neurons. In myenteric AH neurons, IH would act in opposition to the persistent calcium-activated potassium current and thus stabilize the resting potential.

Action Potentials↗
PubMed1990

[Effects of cisapride on gastric emptying].

To evaluate the effects of cisapride on gastric emptying, gastric emptying was measured in six healthy volunteers using radioisotopic techniques which were established three areas of interest, i.e. the whole stomach, the proximal stomach and the antrum. Following results were obtained. 1. At the half emptying times, cisapride induced a more rapid gastric emptying than did placebo in 5 of 6 volunteers. 2. By analyzing gastric emptying curves obtained from three areas of interest, it was suggested that cisapride enhanced the transfer of gastric contents from the proximal stomach to the antrum together with the antral emptying, so that gastric emptying was accelerated.

Adult↗