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Maki Ogawa

Publications and source records attributed to Maki Ogawa.

10 recordsLinked to original sources
PubMed2006

Salivary duct carcinoma with comedonecrosis in the mobile portion of the tongue.

We present a patient suffering from salivary duct carcinoma in the mobile portion of the tongue, arising from a minor salivary gland; this condition is extremely rare. The patient was a 64-year-old woman who presented with a nonpainful, hard mass in her tongue. An aspiration smear showed cells with very scant cytoplasm and pale oval nuclei containing small, single nucleoli. Scattered clusters of small cells had darkly stained nuclei. Neither necrosis nor cribriform areas were seen. The smears suggested a salivary gland neoplasm; however, definitive diagnosis of salivary duct carcinoma remained difficult. Partial glossectomy was performed with a wide margin. Macroscopic examination revealed an unencapsulated, submucosal tumour infiltrating underlying muscle. Microscopic examination revealed a salivary duct carcinoma with comedonecrosis and relatively few cribriform and papillary areas. This case suggests that it may not be easy to establish a definitive diagnosis of salivary duct carcinoma from an aspiration smear if the salivary duct carcinoma is composed of comedonecrosis surrounded by solid tissue in a noncribriform pattern.

Carcinoma, Ductal↗
PubMed2004

Two threonine residues and two serine residues in the second and third intracellular loops are both involved in histamine H1 receptor downregulation.

Human histamine H1 receptor (H1R) contains five possible phosphorylation residues (Thr140, Thr142, Ser396, Ser398 and Thr478) and the substitution of all these five residues to alanine completely impairs agonist-induced receptor downregulation. In the present study, to determine which residue(s) are responsible for receptor downregulation, we used mutant H1Rs in which single or multiple residues were substituted with alanine. The results suggested that two groups, i.e., residues Thr140 and Thr142, and residues Ser396 and Ser398, independently contributed to H1R downregulation. Thr140 and Ser398 mainly contributed to downregulation, and Thr142 or Ser396 had a slight inhibitory effect on Thr140- or Ser398-mediated process, respectively.

Amino Acid Sequence↗
PubMed2004

The variability of liver graft function and urinary 6beta-hydroxycortisol to cortisol ratio during liver regeneration in liver transplant recipients.

The urinary ratio of 6beta-hydroxycortisol to cortisol (6beta-OHF/F) is considered to be the simplest and most practical method for estimation of hepatic cytochrome P450 3A4 (CYP3A4) activity as a non-invasive marker of human in vivo CYP3A4 activity. However, the inter- and intra-individual variability of the urinary 6beta-OHF/F ratio during liver regeneration and the effect of variability on optimal dose of tacrolimus have not yet been clarified. The objective of this study was to clarify the change in the urinary 6beta-OHF/F ratio during liver regeneration and to determine the effect of the liver graft function on the optimal tacrolimus dose in liver transplant recipients. Two liver transplant recipients (one male and one female) and eight healthy volunteers (five males and three females) were enrolled in this study. Urine samples were collected from the recipients from 08.00 hours for 24 h on post-transplant period, 1-10 and 21-30 days postoperatively. In the healthy volunteers, morning spot urine samples were collected at 08.00 hours. The mean urinary 6beta-OHF/F ratio in the immediate postoperative period was significantly low (p < 0.05). However, a marked difference in the regulation of CYP3A4 activity during liver regeneration was found in the two recipients. A significant correlation was found between the urinary 6beta-OHF/F ratio and the C/D ratio of tacrolimus (R = 0.658, p < 0.05). The urinary 6beta-OHF/F ratio is a useful probe for estimating the variability of CYP3A4 activity in liver transplant recipients in early postoperative phase. Future studies should evaluate the clinical usefulness of the urinary 6beta-OHF/F ratio as a predictor of tacrolimus pharmacokinetics in liver transplantation.

Adult↗
PubMed2004

Identification of amino acid residues responsible for agonist-induced down-regulation of histamine H(1) receptors.

The histamine H(1) receptor (H1R) level is dynamically regulated in vivo under various physiological and pathological conditions. The H1R regulation may consist of various processes, and this study focused on the process of receptor trafficking, that is, receptor internalization to endosomes and the following receptor degradation. First, we identified five possible phosphorylation residues of human H1R, Thr(140), Thr(142), Ser(396), Ser(398), and Thr(478), based on in vitro phosphorylation studies. Then to determine the role of these residues, we constructed a mutant H1R in which all of these five residues were substituted with alanine. Both wild-type and the mutant receptors expressed in Chinese hamster ovary (CHO) cells had similar values of K(d) for [(3)H]mepyramine binding and K(i) for histamine, and these cells showed similar levels of histamine-stimulated inositol phosphate formation. Both types of H1Rs were internalized essentially in the same way upon stimulation with histamine (100 microM) for 30 min. However, down-regulation of the mutant H1R was completely impaired, whereas that of wild-type H1R occurred by approximately 60% by the treatment with 100 microM histamine for 24 h. These results suggest that these residues are responsible for receptor down-regulation but not for receptor internalization. Possibly, phosphorylation of the residues is required for receptor transport from endosomes to lysosomes.

Alanine↗
PubMed2003

Synthesis and properties of oligodeoxyribonucleotides containing the new base pairs, Im-N(O):Na-O(N) and Im-O(N):Na-N(O), with the ability to form four hydrogen bonds.

Previously, we synthesized oligodeoxyribonucleotides (ODNs) containing novel base pairing motif consisting of tricyclic nucleosides, Im-N(O) and Im-O(N), with the ability to form four hydrogen bonds (H-bonds). When the base pair, Im-N(O):Im-O(N) pair, was incorporated into the duplex, thermal stability of the duplex depended on the sequence context. In this time, on the basis of previous results, we designed two new bicyclic nucleosides, Na-N(O) and Na-O(N) as complementary nucleobase of the tricyclic nucleobases. These nucleosides were synthesized via a Pd-mediated cross coupling reaction as a key step. When the new Im-O(N):Na-N(O) pair was incorporated into the duplex, it was remarkably stabilized independent of the sequence context.

Base Pairing↗
PubMed2003

[A variant hemoglobin found by dissociation of blood glucose from HbA1c on routine physical examination].

Discrepancy between HbA1c measured by routine HPLC and blood glucose was observed in four out of 340 persons on physical examination. We investigated whether this discrepancy was due to abnormal hemoglobin. HbA1c was measured by routine HPLC and latex agglutination. For further examinations, a hemoglobin specimen was analyzed by weak cation-exchange column(PolyCAT A) chromatography, ESI/MS and MS/MS. HbA1c levels measured by HPLC were about half of those measured by latex agglutination. An abnormal peak between HbA1c and HbA0 was detected on HPLC chromatography in three consanguineous persons. The abnormal hemoglobin from one of the related person was also confirmed by PolyCAT A chromatography. The hemoglobin specimen contained almost same amounts of normal HbA0 and abnormal Hb. Analyses of the globin by ESI/MS and MS/MS revealed that glutamate at the 22nd amino acid residue of the beta-chain was replaced by alanine. This variant was the same as HbG-Coushatta[beta 22(B4) Glu-->Ala]. Family studies showed that the variant was inherited as a dominant trait. The dissociation observed in the case was due to a presence of a variant hemoglobin. In the other case HbA1c levels measured by the two methods were similarly low, and no abnormal peak was observed on HPLC chromatography. Similar studies on the hemoglobin of this case did not disclose any abnormalities. The low values of HbA1c of this case were considered in the lowest region of the normal range.

Aged↗
PubMed2003

Hemoglobin variant HbG-coushatta (beta-22 Glu --> Ala) found by dissociation of blood glucose from values of HbA1C measured by HPLC.

OBJECTIVE: Unexpectedly low values of HbA1C, measured by HPLC compared with their blood glucose levels were found in three related persons. We investigated whether this discrepancy was due to abnormal hemoglobin. PATIENTS AND METHODS: HbA1C was measured by latex agglutination and ordinary HPLC. For further examination, a hemoglobin specimen from the 82-year-old female case was prepared and analyzed by PolyCAT A chromatography, ESI/MS and MS/MS. The HbA1C levels of the three cases measured by HPLC were lower than those measured by latex agglutination. The elution profiles on HPLC of the three gave an unusual peak between HbA1C and HbA0. RESULTS: PolyCAT A chromatography revealed two additional peaks which were not present in normal hemolysates. These peaks were revealed to correspond to abnormalities of HbA0 and HbA1C. The amounts of HbA0 and HbX were almost the same (1:0.85) and their glycation ratios were almost equal (5.2% and 5.9%). ESI/MS showed that the woman's intact globin contained an abnormal beta(X)-chain in addition to the normal alpha(A)- and beta(A)-chains. The molecular weight of this abnormal beta(X)-chain was 58 Da lower than that of the normal beta(A)-chain. Glutamate at the 22nd amino acid residue of the beta(A)-chain was replaced by alanine in the abnormal beta(X)-chain. This variant of Hb was revealed to be the same as HbG-Coushatta (beta-22 Glu --> Ala) from the library of variant Hb. Family studies showed that the variant was inherited as a dominant trait. CONCLUSION: The dissociation was due to underestimation of HbA1C in the measurement by HPLC which excluded glycated variant Hb.

Aged↗