Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 973 records · Page 54Linked to original sources

PubMed1994

Polyclonal human T-cell activation by silicate in vitro.

Silica (SiO2) or related substances such as silicone ([-R2Si-O-]n), which is used in plastic surgery, or asbestos (e.g. chrysotile; 3MgO.2SiO2.H2O) have 'adjuvant effects'. In a study of scleroderma patients in Germany more than 78% had experienced exposure to silicate dust. T-cell receptor (TcR) V beta gene analysis on CD4- CD8- double-negative alpha beta T cells from scleroderma patients, using polymerase chain reaction (PCR), showed that certain V beta genes, V beta 5, V beta 7 and V beta 17, were predominantly expressed in the cells. We found that certain V beta repertoires, V beta 5.3 and V beta 6.7, were predominantly expressed on fractionated T cells with a high Ca2+ level that had been stimulated by chrysotile in vitro. The intracellular Ca2+ level in human peripheral blood mononuclear cells (PBMC) increased after incubation with silica or chrysotile. Interleukin-2 (IL-2) release from PMBC also rose significantly with chrysotile stimulation, but no change was observed when major histocompatibility complex (MHC) class II DP/DR positive cells were depleted. Therefore, our results support the possibility that silicate acts as a superantigen.

Adult↗

PubMed1994

[Survival of patients with gastric cancer treated with intra-lymph nodal injection of activated carbon particles absorbed mitomycin C].

We studied the efficacy of the intra-lymph nodal injection of the activated carbon particle absorbed mitomycin C (MMC-CH40) for gastric cancer. Ninety-five patients with gastric cancer underwent gastrectomy with D1 or D2 lymph node dissection. Of these, 38 patients were treated with intra-lymph nodal injection of MMC-CH 40 (MMC-CH 40 group). The other 57 patients were classified into the control group. The survival of MMC-CH group was significantly higher than that of the control group using generalized Wilcoxon method. However, since the percentage of stage IV was higher in the control group than in MMC-CH 40 group, the survivals of subgroups of stage I-III were compared. Although the percentage of the early gastric cancer was higher in the control group of stage I-III (n = 35) than in the MMC-CH group of stage I-III (n = 38), the survival curves of MMC-CH group were higher than in the control group. The difference in survival between the two groups was significant at 8 months after surgery. These results indicate that this new therapy improves survival in patients with stage I-III gastric cancer.

Absorption↗

PubMed1994

Clinical significance of monocytosis and human monocytic colony-stimulating factor in patients with adult T-cell leukaemia/lymphoma.

We studied 79 patients with adult T-cell leukaemia/lymphoma (ATL) and 11 human T-lymphotropic virus-type I (HTLV-I-carriers to investigate the clinical significance of absolute monocyte counts in peripheral blood. Monocytosis was observed in 20% of ATL patients, but in none of the HTLV-I carriers. ATL patients with absolute monocyte counts above 1.5 x 10(9)/l had a poorer prognosis than those with counts less than 1.5 x 10(9)/l. We also investigated serum levels of human monocytic colony-stimulating factor (hM-CSF) in 7 ATL patients and 11 HTLV-I carriers at the time of diagnosis before chemotherapy, and also in 5 normal healthy individuals. The differences among the 3 groups were not statistically significant. However, markedly increased serum hM-CSF levels were found in 3 ATL patients who were considered to be in the accelerated phase of the disease and 2 of whom were previously diagnosed and had received chemotherapy. There was no correlation between serum hM-CSF level and absolute monocyte count in ATL patients or HTLV-I carriers. The results of hM-CSF assay of supernatants of cultured ATL cells revealed that the ATL cells did not produce hM-CSF themselves. In an ATL patient with pleural involvement, the pleural hM-CSF level was lower than the serum level. These facts indicate that absolute monocyte count is one of the prognostic factors in ATL and the source of the elevated hM-CSF level in some patients with ATL is not ATL cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Severe ascending aortic stenosis after one-stage repair of aortopulmonary window and interrupted aortic arch].

A 33-day-old girl was transferred to our hospital because of severe cyanosis and tachypnea. The diagnosis of aortopulmonary window and interrupted aortic arch was established by echocardiogram and cineangiocardiogram. Reconstruction of aortic arch by extended direct anastomosis and simple patch closure of aortopulmonary window were performed by means of profound hypothermia and circulatory arrest on 36 days of age. Her postoperative clinical course was uneventful, but at 2 months after operation, stenosis of the ascending aorta was noticed by echocardiographic examination. As her physical growth had been satisfactory, she was managed under close observation at outpatient clinic. At seven months after operations, she fell into progressive left heart failure, and emergency operation was carried out for the relief of stenosis of the ascending aorta, but she could not come off bypass. A stenosis of the ascending aorta is a fatal complication that may occur after one-stage repair of interrupted aortic arch with aortopulmonary window consisting of extended direct anastomosis and simple patch closure. We now consider that division of ascending aorta and pulmonary artery and repair of both of the defect is indispensable for the correction of aortopulmonary window, especially in neonate and small infant with this lesion associated with interrupted aortic arch.

Aorta↗

PubMed1994

[A resected case of sporadic myxoma of the right ventricle: the diagnosis was supported with DNA flow cytometry].

We report a rare case of a 16-year-old male who had myxoma originating from septal band of the right ventricle. His ECG anomaly was found incidentally upon a physical examination. Subsequently, echocardiography and angiocardiography demonstrated a tumor occupying the right ventricular outflow tract and protruding into the main pulmonary artery in systolic phase. He was operated upon using extracorporeal circulation. By right ventriculotomy the tumor was resected together with septal tissue 5 mm around the stalk, which branched into the myocardium. The defect was closed using mattress sutures with Dacron felt strips. We also analyzed the DNA content of the tumor. The DNA flow cytometry yielded a single cell population with diploid DNA content. This result showed that the tumor is sporadic form of cardiac myxoma. His postoperative course was uneventful. Thirty months after the surgery, patient has no sign of recurrence. The DNA flow cytometry is helpful for detecting clinical behavior of the cardiac myxoma, because microscopic examination can not readily distinguish sporadic myxoma from so-called complex myxoma.

Adolescent↗

PubMed1994

The natural course of myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine.

The natural course of ossification of the posterior longitudinal ligament, particularly the relationship between the onset of myelopathy and factors associated with its aggravation, was studied in 207 patients during an average period of 10 years 3 months. Myelopathic signs were already present in 37 (18%) patients at the time of the initial examination. Fourteen of these 37 patients showed aggravation of symptoms during the observation period. Myelopathy appeared during the observation period in 33 (16%) of the 207 patients. One hundred thirty-seven (66%) patients were free of myelopathy. Some patients had no myelopathic signs, despite severe spinal stenosis, because of the ossification. In these patients, the range of motion of the cervical spine was severely limited, indicating that dynamic factors are important in the development of myelopathy. In treating this disease, it is necessary to take into consideration the natural course of the disease and to identify the involvement not only of static factors, such as compression caused by ossification, but also of dynamic factors.

Adult↗

PubMed1994

[Surgical treatment of supravalvular aortic stenosis].

In the last 14 years, 7 consecutive patients with supravalvular aortic stenosis (SVAS) underwent surgical treatment for SVAS and/or for associated lesions. There were 5 male and 2 female patients ranging in age from 3 months to 12 years. Six of them had associated other cardiac anomalies; two had severe multiple peripheral pulmonary stenoses (PPS) and one each had ventricular septal defect (VSD), valvular pulmonary stenosis, coarctation of aorta with patent ductus arteriosus (PDA), total anomalous pulmonary venous return (TAPVR) with pulmonary branch stenosis, PPS and left lower pulmonary venous obstruction. The type of SVAS were localized in all and 5 of them underwent successful surgical repair of SVAS (3 with extended aortoplasty and 2 with patch aortoplasty). In 2 patients with VSD or valvular pulmonary stenosis, associated cardiac anomalies and SVAS were repaired simultaneously. Four patients had undergone previous operations, which included repair of severe multiple PPS by extended peripheral pulmonary arterioplasty (case 4, 6), repair of coarctation of aorta and division of PDA (case 5), repair of TAPVR (Ia + IIa) and pulmonary branch stenosis (case 7). There was no operative death and one patient died late postoperatively (case 7) due to right heart failure in a follow up period of 3 to 14 years. In conclusion, it is important to select the appropriate surgical treatment according to the location and the severity of associated other cardiac anomalies as well as the severity of SVAS, and extended peripheral pulmonary arterioplasty is considered to be a recommended method for the relief of severe multiple PPS associated with SVAS.

Aorta↗

PubMed1994

[Ultrasonographic blood flow velocimetry in maternal and umbilical arteries during maternal exercise].

To see hemodynamic changes induced by exercise in pregnant women, we performed blood flow velocimetry with an ultrasonic pulsed Doppler in femoral (FA), external carotid (CA), uterine (UA) and umbilical arteries (Umb A) of pregnant women before and after aerobic dancing at an intensity of approximately 65% maximal heart rates. The subjects were 21 volunteer pregnant women at from 34 to 40 weeks of gestation without obstetrical problems. The velocimetry was done at intervals of five minutes for only one artery of the four arteries. The measurement was repeated 4 times. The following results were obtained: (1) Both pulse rates and blood pressure (BP) increased significantly five minutes after the onset of exercise (p < 0.05) and tachycardia continued for 20 minutes. The intensity of exercise was equivalent to 68.8 +/- 1.1% of the maximal heart rates (mean +/- S.E.). (2) Systolic peak velocity in the FA of the pregnant women increased by 130%, flow volume per minute jumped by 337% (p < 0.05), and the pulsatility index (PI) decreased by 80% (p < 0.05). (3) Neither the systolic peak velocity nor the PI of CA and UA changed significantly. (4) The FHR became tachycardic due to exercise from 142.2 +/- 2.5 bpm to 161.1 +/- 3.8 bpm, associated with the increase in maternal pulse rates. (5) The PI of Umb A was decreased from 0.95 +/- 0.04 to 0.80 +/- 0.03 by exercise. The PI showed a negative correlation (r = -0.37, p < 0.05) with the FHR, not different from a correlation shown without exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Both lisinopril and verapamil reduced platelet-derived growth factor-A chain mRNA levels in human saphenous vein endothelial cells stimulated by thrombin.

BACKGROUND: Both angiotensin-converting enzyme inhibitors and calcium channel blockers decrease postinjury intimal thickening in vivo, but their mechanisms of inhibitory action are unclear. Expression of the gene for platelet-derived growth factor (PDGF), a smooth-muscle mitogen, in endothelial cells (ECs) after vessel injury has been postulated to cause intimal thickening. In this study, we tested whether lisinopril, an angiotensin-converting enzyme inhibitor, or verapamil, a calcium channel blocker, would suppress the PDGF gene expression in stimulated human saphenous vein ECs. METHODS: Drugs were added to replicate EC cultures 30 minutes before adding 10 units/ml alpha-thrombin. Changes in PDGF-A chain mRNA levels were measured by Northern blot analysis or reverse transcription-polymerase chain reaction method. PDGF-AA homodimer in conditioned media was measured by ELISA: RESULTS: Lisinopril attenuated the induction by thrombin of PDGF-A chain mRNA levels significantly in human ECs at doses of 10(-6) mol/L and 10(-5) mol/L (p < 0.05) and appeared to decrease PDGF-AA homodimer released in conditioned medium. Verapamil also reduced thrombin induction of PDGF-A chain mRNA levels significantly at a dose of 10(-5) mol/L (p < 0.05) and appeared to reduce PDGF-AA homodimer secretion. CONCLUSIONS: These data suggest that one means by which lisinopril and verapamil both suppress intimal thickening might be inhibition of PDGF-A chain gene expression in ECs regrowing over vessel injury areas that are sites of thrombin generation.

Base Sequence↗

PubMed1994

[Functional parameters calculated by 99mTc-MAG3 in transplanted kidney].

A newly developed 99mTc-labeled renal tubular agent, 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) was evaluated and compared with 99mTc-DTPA and 123I-OIH in 10 patients with a transplanted kidney. Renal uptake of MAG3 correlated well with both DTPA and OIH; however, these uptake values of MAG3 were lower than those of OIH and higher than those of DTPA. Renogram parameters also correlated well with each other, but excretion of MAG3 was slower than that of OIH and faster than that of DTPA. The bladder to kidney ratio of MAG3 also correlated well, but these ratios of MAG3 were lower than those of OIH and higher than those of DTPA. In conclusion, MAG3 is a promising agent for evaluating the function of transplanted kidney.

Adult↗

PubMed1994

[Additional palliative operation and staged definitive operation for pulmonary atresia with intact ventricular septum].

Between 1981 and 1992, 38 consecutive patients underwent initial operation for pulmonary atresia with intact ventricular septum. Transpulmonary valvotomy using balloon occlusion of RV outflow was carried out in 24 patients at a mean age of 20 days. An additional Blalock-Taussig shunt was required in 4 patients early in the series. Based on a retrospective review on the patients early in the series, initial palliative procedure had been decided in conformity with the value of an index of RV development (RVDI) = RVEDV% x TVD% x RVODmm/BSAm2 x 10(-5), and recent 3 patients with RVDI < 0.35 and patent RV outflow underwent concomitant valvotomy and Blalock-Taussig shunt. Fourteen patients with muscular atresia of RV outflow or major sinusoidal coronary artery communication underwent Blalock-Taussig shunt. There were 1 operative and 3 late deaths and second Blalock-Taussig shunt was required in 6 patients. Definitive repair was carried out in 20 patients between 1985 and 1994. Fifteen patients with RVEDV > 30% of normal had biventricular repair (partial closure of ASD in 6) and 5 underwent Fontan type repair. In terms of the definitive procedures, when the RV.TV index (= RVEDV% x TVD% x 10(-4)) is greater than 0.4, complete repair should be performed. When the index is between 0.2 and 0.4, the atrial septal defect should only be partially closed when the outflow tract is reconstructed. In those cases with an index of less than 0.2, the Fontan procedure seems to be a procedure of choice.

Humans↗

PubMed1993

Interleukin 6 inhibits mouse placental lactogen II but not mouse placental lactogen I secretion in vitro.

The mouse placenta produces several polypeptides belonging to the prolactin-growth hormone gene family, including mouse placental lactogen (mPL) I and mPL-II. The present study was undertaken to determine whether the secretion of mPL-I and mPL-II is regulated by interleukin 6 (IL-6), which is present in the placenta and has previously been reported to stimulate the secretion of pituitary members of this gene family. Effects of human and mouse IL-6 on mPL-I and mPL-II secretion were examined in primary cultures of placental cells from days 7, 9, and 12 of pregnancy. IL-6 caused a dose-dependent reduction in the mPL-II concentration in the medium of cells from days 9 and 12 of pregnancy but did not affect the mPL-II concentration in the medium of cells from day 7 of pregnancy or the mPL-I concentration in the medium of cells from days 7 or 9 of pregnancy. The lowest concentration of human IL-6 that significantly inhibited mPL-II secretion was 250 pM. The effect of IL-6 on the mPL-II concentration in the medium was due primarily to inhibition of mPL-II synthesis, which resulted at least partly from a decrease in the steady-state level of mPL-II mRNA. These data raise the possibility that IL-6 may regulate mPL-II production after midpregnancy in vivo.

Animals↗

PubMed1993

In vitro expansion of human peripheral blood CD34+ cells.

To elucidate the role of recombinant human colony-stimulating factors (CSFs) for expanding peripheral blood (PB) CD34+ cells, these cells were purified up to 94.5% +/- 1.3% and the effects of individual and combined CSFs on the proliferation and differentiation of these cells were studied in a 7-day suspension culture. The majority of CD34+ cells coexpressed CD38 (81.8% +/- 5.1%), but was negative for CD33 (88.5% +/- 3.4%). Among the individual CSFs examined, recombinant interleukin-3 (rIL-3) was identified as the most potent factor for expanding PB progenitor cells and increased nonerythroid progenitor cells 13- +/- 4-fold (P < .01). Recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF), recombinant granulocyte-CSF (rG-CSF), recombinant macrophage-CSF (rM-CSF), rIL-6, rIL-11, and recombinant stem cell factor (rSCF) did not alone expand nonerythroid progenitor cells. A combination of 5 CSFs, ie, rIL-3, rIL-6, rGM-CSF, rG-CSF, and rSCF, was identified as the most potent combination of those tested and increased nonerythroid progenitor cells 57- +/- 11-fold. After a 7-day suspension culture of CD34+ cells with these 5 CSFs, CD34+ cells expanded 14.5-fold, and CD34+/CD33- cells and CD34+/CD33+ cells were also expanded 2.9-fold and 307-fold, respectively. Most secondary colonies derived from expanded cells were small; however, the absolute number of large-sized colonies expanded 5.9- +/- 3.3-fold. Thus, the combination of CSFs can achieve a degree of amplification of PB CD34+ cells. The capability of in vitro expansion of PB CD34+ cells as an adjunct to PB stem cell transplantation is worthy of consideration.

Adult↗

PubMed1993

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. 1. 2-[2-(1-Imidazolyl)alkyl]-1(2H)-phthalazinones.

A number of 4-substituted 2-[omega-(1-imidazolyl)alkyl]-1(2H)-phthalazinones were synthesized in order to develop agents possessing both thromboxane A2 synthetase inhibitory and bronchodilatory activities. The pharmacological evaluation of these compounds disclosed that they have both activities to various extents. Both activities were slightly dependent on the length of the 2-substituents and largely affected by the nature of the 4-substituents. Compounds bearing phenyl and thienyl groups exhibited relatively high and well-rounded activities. Among these compounds, 12j and 15f were found to be the most effective agents having well-rounded activities in vitro and in vivo. Introduction of a carboxyl group reduced both activities contrary to our expectation. 4-(3-Pyridyl)phthalazinone 18b was of particular interest because of unexpectedly high in vivo activities in spite of an absence of significant in vitro activities.

Animals↗

PubMed1993

Novel antiasthmatic agents with dual activities of thromboxane A2 synthetase inhibition and bronchodilation. 2. 4-(3-Pyridyl)-1(2H)-phthalazinones.

A series of novel 4-(3-pyridyl)-1(2H)-phthalazinone derivatives which possess dual activities of thromboxane A2 (TXA2) synthetase inhibition and bronchodilation was synthesized, and their pharmacological activities were evaluated. While the length and the bulk of 2-alkyl substituents had no influence on either activity, the 2-substituents with polar groups reduced bronchodilatory activity. Furthermore, we introduced heteroaromatic nuclei into the 4-position of the phthalazinone and found that 1-imidazolyl (13a) and 5-thiazolyl (16b and 16c) derivatives were as active as the parent 3-pyridyl compound 5b. These findings suggest that heteroaromatic nuclei at the 4-position of phthalazinones play a critical role in TXA2 synthetase inhibition. Additionally, the hydrophobicity of the compounds was found to exert a marked influence on bronchodilatory activity. These observations led to the selection of 2-ethyl-4-(3-pyridyl)-1(2H)-phthalazinone (5b) (KK-505) and 2-methyl-4-(5-thiazolyl)-1(2H)-phthalazinone (16b) (KK-562) for further studies. Although their precise mechanism of action remains unclear, this series of novel phthalazinone derivatives represents a new class of antiasthma agents with dual activities.

Animals↗

PubMed1993

Autopsy report of acute necrotizing opticomyelopathy associated with thyroid cancer.

We report an autopsied case of paraneoplastic necrotizing myelopathy. The patient had bilateral blindness, quadriplegia, and dyspnea of acute onset and died without remission 7 weeks later. The severe tissue necrosis and demyelination were found in the optic chiasm and from the medulla oblongata throughout the whole length of spinal cord. A papillary carcinoma was found in the thyroid gland at autopsy. In the present case IgG, myelin basic protein and activated helper T cells were increased in the CSF at onset, suggesting a mechanism of autoimmune demyelination for the condition.

Autoimmune Diseases↗

PubMed1993

Nucleotide sequence and promoter-specific effect of a negative regulatory region located upstream of the mouse proliferating cell nuclear antigen gene.

Different portions of the 5'-upstream region of the mouse proliferating cell-nuclear-antigen (PCNA) gene were combined with the bacterial chloramphenicol acetyltransferase (CAT) gene of a CAT vector. A transient expression assay of CAT activity in mouse neuroblastoma N18TG2 cells transfected with these recombinant plasmids and RNase protection analysis have revealed the existence of a negative regulatory region between nucleotides -1231 and -624 (+1 denotes the transcription initiation site). The CAT expression levels were gradually increased, depending on the extent of deletion from the 5'-terminus in this region, suggesting that the negative regulatory region consists of multiple elements with rather weak repressing activities. Significant sequence similarity was found between the negative regulatory region of the PCNA gene and those of the several reported genes. A 752-bp segment containing this negative regulatory region repressed the function of the PCNA gene promoter in an orientation-independent and position-independent manner. However, the negative regulatory region showed almost no repressing effect on the functions of the heterologous gene promoters such as the simian virus 40 enhancer promoter, the enhancer promoter in the Rous sarcoma virus long-terminal repeat and the mouse DNA polymerase beta gene promoter. These results suggest that the negative regulatory region of the mouse PCNA gene functions specifically to its own promoter. This unique property is discussed in comparison with that of the negative regulatory elements of the mouse DNA polymerase beta gene.

Animals↗

PubMed1993

Use of glucomannan for the separation of DNA fragments by capillary electrophoresis.

Glucomannan, a natural polysaccharide extracted from Amorphophallus konjac, was employed as a sieving additive for the separation of restriction DNA fragments in capillary electrophoresis. A stable solution of entangled glucomannan was successfully prepared under mild conditions. The separation capillary filled with 0.25% glucomannan exhibited excellent resolution and reproducibility on separation of DNA fragments over the range of ca. 1400 base pairs. The separation was dependent on the size of the fragments, which allowed the determination of the size of separated DNAs directly from the migration time. In addition to these separation characteristics, glucomannan has practical advantages in its chemical stability, non-toxicity and ease of handling. Because the method is applicable to the separation and characterization of the DNA fragments generated by digestion with restriction enzymes or produced by polymerase chain reactions, it is concluded that glucomannan is a good alternative to the conventional sieving additives for capillary electrophoresis, such as polyacrylamide and hydroxymethylcellulose.

Bacteriophage phi X 174↗