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Biomedical subjects

T Asai

Publications and source records attributed to T Asai.

At least 253 records · Page 14Linked to original sources
PubMed1998

Gastric emptying of indigestible solids--a rat model.

The effects of ingestion of digestion of digestible solids and liquids on gastric emptying of indigestible solids were studied. Thirty rats were allocated to one of five groups; in four groups, rats had been fasted for 24 h before the experiment, whereas in the fifth group, they had not been fasted. In all groups, ten steel balls (1.0 mm in diameter) were inserted through an orogastric cannula into the stomach under brief halothane anesthesia. In the four groups of fasted rats, one of the following substance was then given into the stomach: (1) 0.5 g digestible solids; (2) 1.0 ml saline; (3) 1.0 ml contrast medium (45% wv sodium diatrizoate); (4) no substance (control group). Three hours later, the number of balls which had passed into the intestine was counted. Ingestion of 0.5 g meal in fasted rats significantly delayed gastric emptying of steel balls (P < < 0.001), whereas there was no difference in gastric emptying of steel balls between fasted rats and fully fed rats. Ingestion of the contrast medium (P < < 0.001), but not that of saline, significantly delayed the emptying of the balls. Therefore, ingestion of digestible solids or liquids may delay gastric emptying of indigestible solids. Clinical implications of gastric emptying of indigestible solids are discussed.

Animals↗
PubMed1998

[Pitfalls and their solution in MIDCAB].

Between July 1996 and September 1997, 11 patients underwent coronary artery bypass starting with left anterior small thoracotomy. All patients were evaluated with Electron Beam Computed Tomography (EBCT) preoperatively. Two patients out of 11 required conversion to sternotomy due to inadequate length of left internal mammary artery (LIMA) graft. One patient had a graft occlusion and underwent reoperation, when a graft avulsion was identified. Distance between LIMA and LAD by EBCT highly predicted needs of procedure modification to obtain additional length of graft. We demonstrated anterior pericardiopexy as an additional technique for protecting LIMA graft from abnormal tension. We conclude that it is crucial to harvest adequate length of LIMA in MIDCAB and anterior pericardiopexy may be useful to prevent a graft avulsion.

Aged↗
PubMed1998

Effects of morphine, nalbuphine and pentazocine on gastric emptying of indigestible solids.

The effects of morphine (CAS 57-27-2), nalbuphine (CAS 20594-83-6) and pentazocine (CAS 359-83-1) on gastric emptying of indigestible solids were studied. In rats, which were fasted for 24 h, either morphine, nalbuphine, pentazocine or saline was injected intraperitoneally, and ten steel balls (1.0 mm in diameter) were inserted into the stomach. At 3 h, the number of balls which had passed into the small intestine was counted. If these drugs inhibited gastric emptying, naloxone was injected concurrently to study the mechanisms of the inhibitory effect. Morphine, nalbuphine and pentazocine significantly inhibited gastric emptying (ED50:0.041 [95% confidence interval: 0.0078-0.14] mg kg-1, 0.0012 [0.00037-0.0081] mg kg-1 and 0.81 [0.41-1.30] mg kg-1, respectively). Naloxone 0.3 mg kg-1 antagonized the inhibitory effect of both morphine 1.3 mg kg-1 (ED75) and nalbuphine 0.005 mg kg-1 (ED75). In contrast, naloxone 0.3 or 1.0 mg kg-1 did not antagonize the effect of pentazocine 1.9 mg kg-1 (ED75), but a higher dose of naloxone (3.0 mg kg-1) did so. Therefore, in the rat, morphine, nalbuphine and pentazocine inhibit gastric emptying of indigestible solids, and it is likely that morphine and nalbuphine inhibit the emptying through the same opioid receptor, whereas pentazocine does so through a different receptor interaction.

Analgesics, Opioid↗
PubMed1998

[A case of renal pelvic cancer with high serum level of CA 19-9].

A case of left renal pelvic cancer with a high level of serum CA19-9 is reported. Radiological examination showed a left renal pelvic cancer with lymph node metastasis, but did not reveal any tumors producing CA19-9 in any other organs. Chemotherapy was performed in addition to left total nephroureterectomy. The serum level of CA19-9 decreased to the normal range within three weeks after the operation. Immunohistochemical examination demonstrated that CA19-9 might have been produced from the tumor cells themselves in this case.

Biomarkers, Tumor↗
PubMed1997

The absence of effect of gid or mioC transcription on the initiation of chromosomal replication in Escherichia coli.

Despite the widely accepted view that transcription of gid and mioC is required for efficient initiation of cloned oriC, we show that these transcriptions have very little effect on initiation of chromosome replication at wild-type chromosomal oriC. Furthermore, neither gid nor mioC transcription is required in cells deficient in the histone-like proteins Fis or IHF. However, oriC that is sufficiently impaired for initiation by deletion of DnaA box R4 requires transcription of at least one of these genes. We conclude that transcription of mioC and especially gid is needed to activate oriC only under suboptimal conditions. We suggest that either the rifampicin-sensitive step of initiation is some other transcription occurring from promoter(s) within oriC, or the original inference of transcriptional activation derived from the rifampicin experiments is incorrect.

Bacterial Proteins↗
PubMed1997

Partial reconstitution of mammalian phosphoribosylpyrophosphate synthetase in Escherichia coli cells. Coexpression of catalytic subunits with the 39-kDa associated protein leads to formation of soluble multimeric complexes of various compositions.

Rat liver phosphoribosylpyrophosphate (PRPP) synthetase exists as complex aggregates composed of 34-kDa catalytic subunits (PRS I and PRS II) and homologous 39- and 41-kDa proteins termed PRPP synthetase-associated proteins (PAPs). While a negative regulatory role was indicated for PAPs, the physiological function of PAPs is less well understood. We attempted to prepare recombinant 39-kDa PAP (PAP39) and to reconstitute the enzyme complex. Free PAP39 was poorly expressed in Escherichia coli, while expression of protein fused with glutathione S-transferase was successful. The purified fusion protein had no PRPP synthetase activity, and bound to dissociated PRS I and PRS II, with a similar affinity. A free form of PAP39 prepared from the fusion protein formed insoluble aggregates. The enzyme complex was then partially reconstituted in situ by coexpression of PAP39 with PRS I or PRS II in E. coli cells. This coexpression led to formation of soluble complexes of various compositions, depending on the conditions. When the relative amount of PAP39 was higher, specific catalytic activities, in terms of the amount of the catalytic subunit, were lowered. PAP39 complexed with PRS I was more readily degraded by proteolysis than seen with PRS II, in vivo and in vitro. These results provide additional, strong evidence for that PAP39 has no catalytic activity in the enzyme complex, but does exert inhibitory effects in an amount-dependent manner, and that composition of the enzyme complex varies, depending on the relative abundance of components present at the site of aggregate formation.

Adenosine Diphosphate↗
PubMed1997

Propiverine hydrochloride, an anti-pollakiuric agent, inhibits the activity of actomyosin ATPase from the urinary bladder.

The present study was performed to investigate the effects of propiverine hydrochloride (1-methyl-4-piperidyl diphenylpropoxyacetate hydrochloride, P-4), a novel anti-pollakiuric agent, on the contractile proteins of smooth muscle. P-4 (30-300 microM) inhibited the activity of native actomyosin adenosine triphosphatase (ATPase) that had been freshly purified from canine urinary bladder, and calmodulin at 10 microM overcame this inhibition. P-4 also inhibited myosin light chain kinase from smooth muscle in a dose-dependent manner. However, at 300 microM, P-4 was unable to inhibit by 50% the activity of trypsin-treated myosin light chain kinase, which was independent of Ca2+/calmodulin. 1 mol of calmodulin bound 4 to 5 mol of [14C]P-4 in a Ca2+-dependent manner with a K(d) of 77.4 microM. These results indicate that calmodulin is one of the intracellular target molecules for P-4 and that inhibition of the action of calmodulin by P-4 might cause the inhibition of actomyosin ATPase activity, with subsequent relaxation of the smooth muscle of the urinary bladder.

Animals↗
PubMed1997

Identification of heparin-binding sites in midkine and their role in neurite-promotion.

Midkine (MK) is a heparin-binding growth factor, which promotes neurite outgrowth in embryonic neurons and enhances their survival. The three dimensional structure of MK clarified by NMR spectroscopy indicates that several basic amino acids are exposed on the surface of the C-terminal half domain, which retains heparin-binding and neurite-promoting activity. We performed site-directed mutagenesis of these amino acids, and found that mutation of arginine78 reduced the heparin-binding activity. Mutation of either lysine83 or lysine84 scarcely affected heparin-binding activity, while the double mutant involving both lysine residues showed reduction in the activity. Neurite-promoting activity of mutant MKs always correlated with their heparin-binding activity, illustrating the close relationship of the two activities. Thus, the present result verifies the occurrence of two distinct heparin-binding sites involved in neurite-promoting activity of MK molecule.

Animals↗
PubMed1997

Increase in Ref-1 mRNA and protein by thyrotropin in rat thyroid FRTL-5 cells.

Thyrotropin (TSH) induces the expression of fos and jun family genes in thyroid cells. The DNA-binding activity of these gene products (AP-1) has been shown to be enhanced by ubiquitous nuclear redox factor-1 (Ref-1). We thus examined whether TSH regulates Ref-1 gene expression in rat thyroid FRTL-5 cells. Northern blot analysis revealed that the abundance of Ref-1 mRNA significantly increased within 3 hours after TSH followed by a sustained increase until 12 hours. The increase was also induced by treatment with forskolin but not in the presence of cycloheximide, indicating that the TSH effect on Ref-1 mRNA is mediated by intracellular cAMP and requires de novo protein synthesis. Consistent with the elevation of the mRNA level, Western blot analysis showed an increase in Ref-1 protein 3 hours after TSH. The level continued to increase until 12 hours. These results suggested that increased Ref-1 by TSH might regulate the binding activity of AP-1 in thyroid cells. Considering that Ref-1 also has a DNA repair function, Ref-1 may play dual roles in gene regulation and DNA repair processes in thyroid cells.

Animals↗
PubMed1997

Magnetic resonance imaging of reticulo-endothelial system in patients with idiopathic thrombocytopenic purpura.

Idiopathic thrombocytopenic purpura (ITP) is characterized by accelerated platelet destruction in the reticulo-endothelial system (RES). We performed magnetic resonance imaging (MRI) to estimate the degree of activated RES. MRI was performed with a Gyroscan S-15 (1.5 tesla) in 7 healthy volunteers and 22 patients with ITP. The 22 patients included 19 who were at initial diagnosis or were nonresponders to the therapy (non-DX group), and 3 who were responders. For the non-DX group, the T1 relaxation time of the spleen was initially significantly shorter than for healthy volunteers, but normalized after responding to the therapy. The initially shorter T1 values of the spleen for ITP patients correlated with a low platelet count (P < 0.05). This condition may indicate foam cells or fatty components due to platelet destruction. There was no significant relationship between the sequestration in (111)In-scan and T1 values of the liver or spleen. However, MRI is a noninvasive method, and it may be a clinically useful tool in the evaluation of RES in patients with ITP.

Adolescent↗
PubMed1997

Modulation of synovial cell function by somatostatin in patients with rheumatoid arthritis.

OBJECTIVE: To elucidate the role of neurologic, endocrine, and immune system interactions in the development of pathologic responses in patients with rheumatoid arthritis (RA), we studied somatostatin (SOM) production and somatostatin receptor (SOMR) expression in RA synovium and its function in patients with RA. METHODS: The effects of SOM on proinflammatory cytokine (interleukin-6 [IL-6] and IL-8) and collagenase production by RA synovial cells were estimated by enzyme-linked immunosorbent assay, and their messenger RNA expression was assessed by reverse transcription-polymerase chain reaction (RT-PCR) using limiting dilutions of the complementary DNA. The expression of SOMR by RA synovial cells was also studied by RT-PCR. Local production of SOM was estimated by RT-PCR and immunohistochemical staining. RESULTS: Physiologic concentrations (approximately 10(-10)M) of SOM inhibited proliferation of RA synovial cells. The production of proinflammatory cytokines and matrix metalloproteinases by RA synovial cells was also modulated by SOM. SOMR subtypes 1 and 2 were expressed on fibroblast-like synovial cells, and the expression of SOMR-2 was up-regulated by proinflammatory cytokine treatment of the synovial cells from patients with RA. RA fibroblast-like cells synthesized SOM by themselves, suggesting that SOM acts as an autocrine regulator of synovial cell function in patients with RA. CONCLUSION: SOM inhibited aberrant synovial cell function in patients with RA, suggesting possible clinical applications of this neuropeptide.

Activating Transcription Factor 1↗
PubMed1997

Identification of Entamoeba histolytica and E. dispar cysts in stool by polymerase chain reaction.

An attempt to identify cysts of Entamoeba histolytica and E. dispar in human stool was conducted by polymerase chain reaction (PCR) using two sets of primers (p11 plus p12 and p13 plus p14) specific for either species of ameba. The cysts in stool specimens obtained from 12 infected individuals were concentrated, freeze-thawed, and treated with Triton X-100 before their examination by PCR. The results of PCR on the cysts were generally consistent with data obtained by PCR on ameba trophozoites hatched from the cysts, by zymodeme analysis, and by enzyme-linked immunosorbent assay (ELISA) and with clinical findings. This PCR was negative for the stool containing large numbers of cysts of either E. coli, E. hartmanni, or Giardia lamblia as well as for the stool specimens obtained from uninfected individuals. The ameba cyst in stool processed using the present method was effective for the PCR analysis even after 1 month of storage at 4 degrees C. The present PCR was sensitive enough to detect ten cysts of either of the amebae.

Animals↗
PubMed1997

Simple in-office closure of small intractable tympanic membrane perforations after myringoplasty.

Perforations produced following myringoplasty are very difficult to close by ordinary cautery or patching even if they are small. Therefore we decided to close these intractable perforations with a skin graft from the cartilaginous ear canal. Our method is an in-office operation under local anesthesia. After the removal of epithelium from around the perforation a skin graft was placed by the over-lay method. A total of 11 patients were treated, of which 81.8% (9/11) demonstrated successful closure in the initial surgery and two re-perforations were successfully closed by a second and third operation, respectively. The technique used in this surgery is relatively easy and appropriate for in-office operations. The method's advantages include decreased invasiveness with minimal anesthesia and no requirement for ear canal packing or fixatives, and cosmetic benefit. This method also can be applied to perforations caused by chronic otitis media, traumatic perforations, and perforations after inserting tubes.

Adolescent↗
PubMed1997

Clonidine inhibits gastric motility in the rat.

We have studied the effect of clonidine on gastric motility, by examining the effect on gastric emptying of indigestible solids. In Wistar rats, either clonidine or saline was injected intraperitoneally, and ten steel balls (1.0 mm in diameter) were inserted into the stomach. Gastric emptying was examined at 3 h. Clonidine delayed gastric emptying of steel balls (ED50 = 0.0071 [95% confidence interval: 0.0033-0.013) mg kg-1). Yohimbine, but not naloxone, significantly antagonized the inhibitory effect of clonidine. We conclude that clonidine inhibits gastric motility through the alpha 2 adrenoceptor.

Adjuvants, Anesthesia↗