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M Koizumi

Publications and source records attributed to M Koizumi.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Serum concentration of pyridinoline cross-linked carboxy-terminal telopeptide of type-I collagen (ICTP) and carboxyterminal propeptide of human type I procollagen (PICP) in the diagnosis of bone metastases].

Recently discovered bone metabolic markers are expected to play an additional role in the diagnosis of bone metastasis. We measured bone metabolic markers, serum pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen (ICTP) and carboxyterminal propeptide of human type I procollagen (PICP) in 224 patients with breast cancer (106 with bone metastases), 61 patients with prostatic cancer (30 with bone metastases), 45 patients with lung cancer (17 with bone metastases) and 13 patients with miscellaneous cancers (7 with bone metastasis) and compared the values in the presence and absence of bone metastasis. ICTP and PICP increased significantly in patients with bone metastases. By the analysis of sensitivity and specificity, the cut-off levels were considered to be 5.0 ng/ml for ICTP and 140 ng/ml for PICP. In lung cancer (bone metastases are mostly of osteolytic), ICTP was excellent marker in detecting bone metastasis. In breast cancer (bone metastases are mostly of mixed type), ICTP was good in detecting bone metastases. In prostatic cancer (bone metastases are mostly of osteoblastic), ICTP and PICP were good markers in detecting high grade of bone metastases. Over all, ICTP was more sensitive in the diagnosis of bone metastases than PICP. However, both markers were not effective in detecting low grade bone metastases. ICTP and PICP should play a supportive role to imaging modalities in the diagnosis of bone metastases.

Aged↗
PubMed1995

Lipopolysaccharide induces manganese superoxide dismutase in the rat pancreas: its role in caerulein pancreatitis.

Intraperitoneal injection of lipopolysaccharide (LPS) at a dose of 50 micrograms/kg increased the activity and the mRNA level of manganese superoxide dismutase (Mn-SOD) but did not change those of copper/zinc-SOD (Cu/Zn-SOD) in the rat pancreas. Both the formation of pancreatic edema and the elevation of serum amylase during caerulein pancreatitis were significantly relieved in the rats pretreated with LPS (50 micrograms/kg) compared with the rats without the pretreatment. These results support the view that superoxides play a key role in the pathogenesis of caerulein pancreatitis, and that Mn-SOD in the pancreas may work as a defense against the development of this disease.

Animals↗
PubMed1995

Modification of primary structures of hairpin ribozymes for probing active conformations.

Hairpin ribozymes consist of two stem-loop domains, and these domains are assumed to interact with each other to produce the self-cleavage activity. We have studied the relationship of the tertiary structure of the hairpin ribozyme and the cleavage activity by dividing and re-joining the domains. A hairpin ribozyme (E50) was divided at the hinge region, and the main part was joined to a substrate (S1) using tri- or penta-cytidylates. These ribozymes retained the cleavage activity in the presence of the rest of the molecule, indicating that the active conformation could be maintained if the two domains interacted with each other. Based on the these results, we designed a new type of hairpin ribozyme by replacing one of the domains. To maintain the interaction of the domains, oligocytidylates were inserted at a junction. These reversely jointed ribozyme complexes showed cleavage activity that was dependent on the linker lengths. These modifications in the primary structure of the hairpin ribozyme confirm the structural requirement for the catalytic reaction and provide information for the correlation of the tertiary structure with the cleavage of the hairpin ribozyme.

Base Sequence↗
PubMed1995

Bone metabolic markers in bone metastases.

The efficacy and cost/performance benefit of radionuclide bone scintigraphy in monitoring metastatic bone activity remain controversial. Recently developed bone metabolic markers are expected to play an additional role in the diagnosis of bone metastasis. We measured osteoclastic and osteoblastic markers in 267 patients with breast cancer (100 with bone metastasis), 38 patients with prostatic cancer (25 with bone metastasis), 50 patients with lung cancer (12 with bone metastasis) and 33 patients with miscellaneous cancers (13 with bone metastasis) and compared the values in the presence and absence of bone metastasis. Bone metabolic markers, both osteoclastic and osteoblastic, increased significantly in patients with bone metastasis. In breast cancer (bone metastasis is mostly of the mixed type), osteoclastic markers were good in detecting bone metastasis. In prostatic cancer (bone metastasis is mostly osteoblastic), osteoclastic and osteoblastic markers were equally effective in detecting bone metastasis. In lung cancer (bone metastasis is mostly osteolytic), osteoclastic markers were elevated preferentially in bone metastasis. Over all, osteoclastic markers were more sensitive in the diagnosis of bone metastasis, and among osteoclastic markers, serum pyridionoline-cross-linked carboxyterminal telopeptide was the most efficient in both specificity (91.0%) and sensitivity (48.6%) for detecting bone metastasis.

Aged↗
PubMed1995

Effects of cisapride on gallbladder emptying and pancreatic polypeptide and cholecystokinin release in humans.

We investigated the effects of cisapride on gallbladder motility and on the release of pancreatic polypeptide and cholecystokinin in the fasting and postprandial states. Cisapride (7.5 mg) and/or a test meal was administered intraduodenally to seven healthy volunteers with or without atropine pretreatment (0.5 mg, i.m.). In the fasting state, cisapride increased gallbladder volume to 154% of the basal level, and significantly elevated plasma pancreatic polypeptide levels. The effects of cisapride were inhibited by atropine. In the postprandial state, integrated pancreatic polypeptide and cholecystokinin responses were increased by cisapride to 180% and 192%, respectively, of control values. Atropine inhibited the integrated gallbladder and pancreatic polypeptide response to about 60% of the control value, but did not affect the cholecystokinin response. These observations suggest that: (1) fasting gallbladder tone is influenced by cholinergic inhibitory mechanisms, (2) acetylcholine (ACh) is the final mediator for about 40% of the postprandial gallbladder emptying and pancreatic polypeptide response, and (3) coordination between the ACh-independent cholecystokinin response and ACh-dependent pancreatic polypeptide response may be important in the regulation of postprandial gallbladder emptying.

Adult↗
PubMed1995

Nitric oxide modulates pancreatic edema formation in rat caerulein-induced pancreatitis.

This study was designed to investigate the role of nitric oxide (NO) in the formation of pancreatic edema in caerulein-induced pancreatitis in rats. Pancreatitis was produced by two intraperitoneal injections of caerulein, and plasma amylase concentration, pancreatic edema index (pancreatic wet weight/body weight), and Evans blue extravasation (as a measure of vascular permeability) were evaluated 5 h after the first injection. Four doses (1, 2.5, 5, and 10 mg/kg) of NG-nitro-L-arginine (L-NNA), an NO synthase inhibitor, were subcutaneously administered at -0.5, 0.5, 1.5, 2.5, and 3.5 h after the first injection of caerulein. L-NNA significantly lowered the edema index, the wet/dry weight ratio of the pancreas, and Evans blue extravasation in the rats with pancreatitis. The maximal effect was obtained by L-NNA at a dose of 2.5 mg/kg; this inhibited the increase in pancreatic edema formation from the control value by 60%-70%. Intraperitoneal injections (20 mg/kg, five times) of L-arginine, a substrate for NO production, partly reversed the L-NNA-induced inhibition of pancreatic edema formation, but D-arginine, an enantiomer of L-arginine, did not show any effect. Plasma amylase concentrations were not significantly affected by any dose of L-NNA, nor were they affected by L- or D-arginine. These findings strongly suggest that endogenous NO plays an important role in the formation of pancreatic edema in caerulein-induced pancreatitis in rats, probably by increasing vascular permeability and protein extravasation.

Acute Disease↗
PubMed1995

Scintigraphic detection of recurrence of medullary thyroid cancer.

A case of recurrent medullary thyroid cancer (MTC) was evaluated with 123I-MIBG, 99mTc(V)-dimercaptosuccinic acid (DMSA), and 201Tl scintigraphy. This patient had been operated on for MTC in the right thyroid. Recently a left neck mass was noticed, and was suspected of being a recurrence of MTC based on increased plasma calcitonin (CT) and carcinoembryonic antigen (CEA). He was operated on for the neck mass which revealed MTC, and papillary thyroid cancer was incidentally found in the left thyroid, but the CT and CEA levels remained high, and remaining MTC tumor was suspected. But the location of the tumor was unknown. Although 99mTc(V)-DMSA scintigraphy is generally believed to be superior in sensitivity to 123I-MIBG scintigraphy, it did not demonstrate the tumor site but 201Tl and 123I-MIBG did. Furthermore, 123I-MIBG scintigraphy has greater specificity for tumors which arise in the neural crest. Judging from the results of this case and cases reported in the literatures, both 123I-MIBG and 99mTc(V)-DMSA should be performed in the detection of recurrent MTC.

3-Iodobenzylguanidine↗
PubMed1995

The role of endogenous glucocorticoids in rat experimental models of acute pancreatitis.

BACKGROUND & AIMS: Cytokines activate the hypothalamic-pituitary-adrenal axis and suppress inflammation by stimulating glucocorticoid secretion. The state of adrenocortical function during acute pancreatitis and its role in this disease were determined. METHODS: Cerulein-induced pancreatitis or closed duodenal loop pancreatitis was produced in rats that had undergone adrenalectomy or sham adrenalectomy, and the serum corticosterone and interleukin 8 levels and the intensity of the pancreatitis were examined. RESULTS: Serum corticosterone levels were significantly higher than basal levels in both models of experimental pancreatitis. In both models, adrenalectomy increased serum amylase and pancreatic edema and produced more severe inflammation. Adrenalectomy significantly increased mortality in animals with closed duodenal loop pancreatitis. Exogenous hydrocortisone administered to adrenalectomized animals suppressed the elevation of serum interleukin 8 levels and decreased both the severity of pancreatitis and mortality. CONCLUSIONS: These results suggest that the adrenocortical function is stimulated during acute pancreatitis and that the secretion of endogenous glucocorticoids may play an important role in mitigating the progress of this disease, probably by inhibiting cytokine production.

Acute Disease↗
PubMed1995

Phylogenetic position of yeast-like symbiotes of rice planthoppers based on partial 18S rDNA sequences.

The rice planthoppers, Nilaparvata lugens, Sogatella furcifera, and Laodelphax striatellus, harbor intracellular yeast-like symbiotes (YLS) in the fat body. The YLS are obligated endosymbiotes and are transovarially inherited. Nucleotide sequences of the 18S rRNA genes from the YLS were analyzed by direct sequencing. The YLS of the three species of planthoppers were monophyletic and their taxonomic positions were in the class Pyrenomycetes in the subphylum Ascomycotina.

Animals↗
PubMed1995

Structural composition of hammerhead ribozymes.

Eleven kinds of hammerhead ribozymes were designed and synthesized to investigate the structural composition of the complexes and to find suitable crystallization conditions, the substrate chains having been modified to prevent hydrolysis. Electrophoresis patterns indicated that the two strands except for the substrate chain form a binary complex and that they form a ternary complex when mixed with the substrate chain. Both complexes were crystallized. The crystal of the binary complex belongs to a Laue symmetry of 32 (space group of P321, P3(1)21, or P3(2)21) with cell dimensions of a = b = 53.4 and c = 59.4 A. The volume per one nucleotide allows the asymmetric unit to contain one binary complex. Our results suggest that the catalytic part forms a rigid ribozyme structure which induces a scissile reaction when the substrate is bound, in a similar manner to an enzyme protein.

Base Sequence↗
PubMed1995

The effect of helodermin in rat dispersed pancreatic acini.

Helodermin is a 35 amino acid-residue peptide of the vasoactive intestinal polypeptide (VIP) family, which was originally isolated from the venom of Heloderma suspectum on the basis of its capacity to stimulate adenylate cyclase in the rat pancreas. In the present study, using rat dispersed pancreatic acini, we examined the binding characteristics of helodermin, its action on amylase secretion, and the production of intracellular cyclic AMP (cAMP). Helodermin stimulated intracellular cAMP production dose dependently in a manner that was nearly identical to that of VIP. Helodermin stimulated amylase secretion dose dependently, showing an efficacy similar to that of VIP but with 100 times less potency than VIP. Adding 0.5 mM 3-isobutyl-1-methylxanthine increased the potency of helodermin's action on amylase secretion but did not change the efficacy. The binding study showed that the order of binding affinity to VIP receptors was VIP = helodermin > secretin, while the order of that to secretin receptors was secretin > helodermin > VIP. These results suggest that helodermin stimulated amylase secretion from rat dispersed pancreatic acini via VIP-preferring receptors that are coupled to the production of intracellular cAMP, but a part of the postreceptor mechanism for enzyme secretion is different from that of VIP.

Amylases↗
PubMed1995

Regulation of arylsulfate sulfotransferase from a human intestinal bacterium by nucleotides and magnesium ion.

Arylsulfate sulfotransferase (ASST) from a human intestinal bacterium stoichiometrically catalyzed the transfer of a sulfate group from phenylsulfate esters to phenolic compounds. Pentachlorophenol, one of the selective inhibitors of phenol sulfoconjugation in mammalian tissues, inhibited both phenol and tyramine sulfation by ASST. Nucleotide triphosphates such as ATP, GTP, UTP and CTP, and pyrophosphate inhibited the ASST activity, whereas Mg2+ and Mn2+ activated the enzyme and prevented its inhibition by ATP and pyrophosphate. Equimolar binding of [alpha-] and [gamma-32P]ATP to the enzyme showed that the enzyme protein was not phosphorylated, but bound ATP. These results suggest that nucleotide triphosphates and divalent cations are important modulators in the control of ASST activity.

Adenosine Triphosphate↗
PubMed1995

[Planning for brachytherapy using a 3D-simulation model].

A 3D-simulation model made with a milling system was applied to HDR-brachytherapy. The 3D-simulation model is used to simulate the 3D-structure of the lesion and the surrounding organs before the actual catheterization for brachytherapy. The first case was recurrent prostatic cancer in a 61-year-old man. The other case was lymph node recurrence of a 71-year-old woman's upper gum cancer. In both cases, the 3D-simulation model was very useful to simulate the 3D-conformation, to plan the treatment process and to avoid the risk accompanying treatment.

Aged↗
PubMed1995

The nerve supply to coracobrachialis in apes.

The origin of the nerve supply to coracobrachialis from the brachial plexus in apes was investigated in 4 arms from 4 chimpanzees, both arms of a gorilla and 4 arms from 4 gibbons. The general architecture of the brachial plexus was the same as in the human. In the apes examined, the nerves supplying this muscle could be classified into 2 groups: (1) distal branches arising from the musculocutaneous nerve, and (2) proximal branches arising in the region of the lateral cord. On the basis of their origin and course, the proximal branches were classified into 3 types, namely a deep ramus arising from the middle trunk and passing dorsal to the upper trunk, a medial ramus arising from the upper trunk in the lateral cord, and a superficial ramus arising from the ventral surface of the middle trunk or the root of the pectoral nerve. This classification also applies to branches to coracobrachialis in man. The 3 types of proximal branch often communicated with each other to supply coracobrachialis, whereas the proximal and distal branches were separated from each other spatially. This indicates that coracobrachialis possesses characteristics both of the pectoral girdle muscles and the flexor muscles of the upper arm.

Animals↗
PubMed1995

[BT-PABA test].

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4-Aminobenzoic Acid↗
PubMed1995

Design and anti-HIV-1 activity of ribozymes that cleave HIV-1 LTR.

A hairpin ribozyme (HR112) and two hammerhead ribozymes (RZ115 and RZ119) containing a 5'C(UUCG)G3' loop were designed to cleave the long terminal repeat (LTR) of HIV-1. When the ribozyme catalyzed RNA cleavage reaction for a chemically synthesized 19 mer (LTR 19) was measured, the t 1/2 value of LTR 19 mediated by RZ115 was smaller than that of the RZ119 case. Moreover, the transformed CEM cells harboring the gene encoding these ribozymes were challenged with a HIV-1IIIB strain, two ribozymes, HR112 and RZ119 possessed strong anti-HIV-1 activity. However, the anti-HIV-1 activity displayed by RZ115 was weak. On the basis of secondary structure predictions of the RNA transcribed with the gene encoding ribozymes, the secondary structure of the transcribed RNA with RZ115 sequences was observed to be different from those with the other ribozymes. It has been demonstrated that the secondary structures of transcribed RNAs can possibly influence the anti-HIV-1 activity.

Antiviral Agents↗
PubMed1995

Construction of new hairpin ribozymes with replaced domains.

We have constructed a new type of hairpin ribozyme by cleaving and reverse-joining one of the two catalytic domains to conserve an essential bending structure. The two domains of the new ribozymes were tethered by different lengths of cytidylate linkers. These ribozymes retained the cleavage activity and the cleavage activities depended on the linker lengths. Although these rejoined ribozymes showed weak turnover abilities, those with 18 cytidylates showed a larger kcat/K(m) value than the natural hairpin ribozymes. These modifications in the primary structure of the hairpin ribozyme confirm the bent conformation for the catalytic reaction of this ribozyme, and provide a new approach for the design of highly efficient ribozymes.

Base Sequence↗