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Biomedical subjects

A Kawaguchi

Publications and source records attributed to A Kawaguchi.

At least 91 records · Page 5Linked to original sources
PubMed1997

Regulation by thyroid-stimulating hormone of sodium/iodide symporter gene expression and protein levels in FRTL-5 cells.

To investigate the mechanism of I- transport stimulation by TSH, we studied the effects of TSH on Na+/I- symporter (NIS) messenger RNA (mRNA) and protein levels in FRTL-5 cells and correlated these with I- transport activity. When 1 mU/ml TSH was added to quiescent FRTL-5 cells, a 12-h latency was observed before the onset of increased I- transport activity, which reached a maximum [approximately 27 times basal (5H medium) levels] at 72 h. In contrast, Northern blot analysis, using rat NIS complementary DNA as a probe, revealed that addition of TSH to these cells significantly increased NIS mRNA at 3-6 h, reaching a maximum after 24 h (approximately 5.9 times basal levels). Forskolin and (Bu)2cAMP mimicked this stimulatory effect on both the I- transport activity and mRNA levels. D-ribofranosylbenzimidazole, a transcription inhibitor, almost completely blocked TSH-induced stimulation of I- transport and NIS mRNA levels. Western blot analysis demonstrated that TSH increased NIS protein levels at 36 h, reaching a maximum at 72 h, in parallel with the kinetics of TSH-induced I- transport activity. However, it also showed that the amount of NIS protein already present in FRTL-5 cell membranes before the addition of TSH was about one third of the maximum level induced by TSH. These results indicate that stimulation of I- transport activity by TSH in thyrocytes is partly due to a rapid increase in NIS gene expression, followed by a relatively slow NIS protein synthesis. However, the existence of an abundant amount of protein in quiescent FRTL-5 cells with very low I- transport activity also suggests that this activity is controlled by another TSH-regulated factor(s).

Animals↗
PubMed1997

Increased expression of the Na+/I- symporter in cultured human thyroid cells exposed to thyrotropin and in Graves' thyroid tissue.

The Na+/I- symporter (NIS) is important in hormone synthesis in the thyroid gland. NIS activity, as reflected by I- uptake, was increased by TSH (1 mU/mL) or forskolin (10 mumol/L) in primary cultured human thyroid cells. Northern blot analysis revealed that incubation of these cells with TSH or forskolin for 24 h increased the abundance of NIS messenger ribonucleic acid (mRNA) 2.3- and 2.5-fold, respectively. Immunoblot analysis revealed 2.7- and 2.4-fold increases, respectively, in the amount of NIS protein after 48 h, suggesting that elevated levels of intracellular cAMP induced the expression of NIS in human thyrocytes. We then studied the levels of NIS mRNA and protein in Graves' thyroid tissue and found that the amount of NIS mRNA in thyroid tissue from individuals with Graves' disease (n = 5) was 3.8 times that in normal thyroid tissue (n = 5). The abundance of NIS mRNA was significantly correlated with that of thyroid peroxidase or thyroglobulin mRNAs, but not with that of TSH receptor mRNA, in the Graves' and normal thyroid tissue specimens. The amount of NIS protein was also increased 3.1-fold in Graves' thyroid tissue compared with that in normal thyroid tissue. The increased expression of NIS may thus contribute to the development of Graves' disease.

Blotting, Northern↗
PubMed1997

Genetic profiles of newly inbred Dahl/Iwai salt-sensitive and salt-resistant rats.

Dahl-Iwai salt-sensitive (S) and salt-resistant (R) rat strains were established as inbred strains at Brookhaven National Laboratory, NY, and were introduced into Eisai Co., Ltd., Japan, and designated DIS/Eis and DIR/Eis. To examine whether there are different allele distributions among the substrains of inbred Dahl S and R rats, we determined biochemical and immunological alleles of DIS/Eis and DIR/Eis, and SS/Sea and SR/Sea, which were derived from SS/Jr and SR/Jr, which were developed by Rapp and Dene. Several differences of allele distribution were observed, indicating that the substrains have different genetic backgrounds. The phenotypic differences between the substrains, such as the severity of the hypertension induced, could be ascribed to the different genetic backgrounds.

Alleles↗
PubMed1997

[Evaluation of ileocolon interposition after total gastrectomy].

The most serious complaints after total gastrectomy are alkaline esophagitis and postalimentary syndrome. We have performed ileocolon interposition as a gastric substitution which uses the ileocecal valve to prevent bile reflux. The ileocolon segment consists of 7 cm of terminal ileum and 10 cm of coecum and ascending colon on a vascular pedicle. This isolated segment is rotated upwards between the esophagus and the duodenum. To evaluate the function of the ileocolon as a gastric substitute, Barium X rays, O-GTT and gastric emptying time (99Tc EDTA) were examined. Barium X-rays showed that the air at the coecal portion looks like a gastric fornix and there is no barium reflux into the esophagus even in the supine position. Likewise, there were no complaints from patients of symptoms of reflux esophagitis. In case of Rouxen-Y reconstructions, blood sugar level after O-GTT show oxyhyperglycemia. Those in ileocolon interposition rose rapidly, but almost to the same degree as in normal subjects. The appearance of the gastric emptying curve using Tc-DTPA in case of ileocolon interposition shows that there is good reservoir function.

Colon↗
PubMed1996

A case of small cell carcinoma of the uterine cervix presenting Cushing's syndrome.

A proportion of small cell carcinoma of the uterine cervix is known to secrete a neuroendocrine substance. However, cases presenting Cushing's syndrome due to ACTH secreted from a cervical small cell carcinoma are extremely rare. Here, we report a case of small cell carcinoma of the uterine cervix that ectopically secreted ACTH and presented Cushing's syndrome. A 42-year-old woman was initially admitted to the endocrine unit for investigation of ectopic ACTH syndrome. Serum cortisol and plasma ACTH levels were elevated with no diurnal variation. After gynecologic examination, her original disease was found to be a stage IIb cervical small cell carcinoma. She underwent a radical hysterectomy and pelvic lymphadenectomy. The entire tumor was excised and post-TNM classification was T2bN1M0. Immunohistochemically, tumor cells stained strongly for ACTH and chromogranin. Electronmicroscopic pictures showed typical neurosecretory granules. Although plasma ACTH returned to normal after surgery, liver metastasis appeared during the course of postoperative irradiation. She died 9 months after operation in spite of vigorous systemic chemotherapy.

Adrenocorticotropic Hormone↗
PubMed1996

Endothelins contract guinea-pig pulmonary artery and enhance its adrenergic response via ET(A) receptors.

1. This study has pharmacologically characterized endothelin (ET) receptor subtype(s) mediating contraction and enhancement of adrenergic contraction in guinea-pig pulmonary artery. Isometric tension of the isolated endothelium-denuded ring preparations was measured in the presence of indomethacin (10(-5) mol/L) and N(G)-nitro-L-arginine methyl ester (L-NAME; 3 x 10(4) mol/L) to exclude a mechanism via endothelium, cyclo-oxygenase-generated eicosanoids and nitric oxide. 2. In the additional presence of tetrodotoxin (TTX; 3 x 10(-7) mol/L), ET-1 (10(-11)-10(-7) mol/L) concentration-dependently contracted the preparations. The rank order of potency to contract the preparations among ET receptor agonists was ET-1, sarafotoxin (STX)6b > ET-3 > IRL 1620, STX 6c. BQ-123 (7 x 10(-7)-7 x 10(-6) mol/L) concentrations-dependently shifted the concentration-contraction curve for ET-1 to the right in a parallel manner. Pretreatment with STX 6c (3 x 10(-7) mol/L for 30 min) did not significantly desensitize contractions to ET-1, ET-3 or IRL 1620 (P > 0.05; t-test, 10 d.f). 3. ET-1 (10(-10)-10(-9) mol/L) and STX 6b (10(-9)-10(-8) mol/L) significantly enhanced the electrical field stimulation-induced contraction in a BQ-123-sensitive manner (P < 0.05: t-test, 24-38 d.f), while ET-3 (10(-11)-10(-8) mol/L) and STX 6c (10(-11)-10(-7) mol/L) did not affect contractions. ET-1 (10(-11) mol/L) significantly enhanced contractions to exogenous noradrenaline in the presence of TTX (3 x 10(-7) mol/L) (P < 0.05; t-test, 16 d.f.). 4. These data indicate that the BQ-123-sensitive ET(A) receptor mediates both contraction and enhancement of adrenergic contractions in the guinea-pig pulmonary artery.

Animals↗
PubMed1996

[Review of results after surgery for pulmonary embolism].

The results of direct pulmonary embolectomy in 20 cases of pulmonary embolism treated in our facility from 1982 to May, 1995 was analyzed. The ages of the patients ranged from 25 to 72 years (mean: 46 years). The male-to-female ratio was 12:8. The 20 cases were divided into three groups based on the type of pulmonary embolism: Group I (4 cases of acute massive pulmonary thrombo-embolism). Group II (12 cases of chronic pulmonary thrombo-embolism) and Group III (4 cases of tumor embolism). In Group I, 2 patients developed shock and 2 developed severe right heart failure. Emergency thrombectomy using cardiopulmonary bypass succeeded in saving the lives of 3 patients in this group. In Group II, the preoperative NYHA grade was II in 1 case, III in 9 cases, and IV in 2 cases. The preoperative systolic pressure of the pulmonary artery ranged from 24 to 90 mmHg (mean: 74 mmHg). Surgery through a thoracotomy was carried out on 7 cases (on the right side in 4 cases on the left in 3 cases). Of these 7 patients, 2 died of heart failure and respiratory failure because thromboendarterectomy was inadequate. In another 2 patients, symptoms improved enough to allow them to resume their previous lives. The other three patients showed no change in their symptoms after surgery, but they could be discharged. The remaining 5 patients in Group II underwent surgery through the median approach. Deep hypothermia with circulatory arrest was used in the latter 4 of these 5 patients during surgery. 3 patients died during the perioperative period because adequate thromboendarterectomy was not possible and because their preoperative condition was very poor. 2 patients who were able to be performed adequate thromboendarterectomy showed good postoperative courses. Of the 4 patients in Group III, one patient survived 11 months after surgery, but the other 3 died during the preoperative period because very little embolus could be removed. These results allow us to conclude that the lives of patients with acute pulmonary thromboembolism can be saved by early detection and prompt surgery, but that management of chronic pulmonary thromboembolism involves difficulties in selecting surgical cases and in performing thromboendarterectomy.

Adult↗
PubMed1996

[Informed consent of the esophageal cancer].

An informed consent (IC) is composed of sufficient explanation from medical providers about illness and proposed treatment and its acceptance by a patient with a principal intention to protect patients. Esophageal cancer has some characteristic features in contrast to other malignancy that is (1) high prevalence in elderly with advanced stage (2) significant malignant potential in nature (3) high surgical risk with mortality of 3% and morbidity of over 50% (4) availability of diverse treatment modality such as resection, irradiation and chemotherapy. Therefore it is highly advised for medical providers to inform patients of their diagnosis and explain anticipated surgical risks to help them understand the negative features mentioned above although extent of revelation of illness should be highly individualized according to the judgment of medical providers. It is also mandatory for medical providers to inform patients of available treatment modalities applicable according to the stage of disease and evaluated surgical risk before obtaining a consent to a proposed treatment. Illustrated figures advocate patients to further understand the stage of disease, the necessity of proposed treatment, surgical risk with anticipated complication etc, and explanatory forms if accompanied are even more helpful in this respect. An informed consent is to be signed to verify the acceptance of a proposed treatment by a patients who has been fully aware of illness. An informed consent should be utilized to establish ensured patient, doctor relationship through its make-up process instead of being considered as an exclusive legal document of agreement.

Esophageal Neoplasms↗
PubMed1995

Impaired photosystem II in a mutant of Chlamydomonas reinhardtii defective in sulfoquinovosyl diacylglycerol.

The photosynthetic apparatus was characterized in a mutant of Chlamydomonas reinhardtii, hf-2, defective in the synthesis of a chloroplast-specific lipid, sulfoquinovosyl diacylglycerol (SQui-acyl2Gro). hf-2 showed reduced photosystem II (PSII) activity with little effect on photosystem I (PSI) activity, as compared with the parent. PAGE in the presence of dodecyl beta-D-maltoside (DodGlc2) of C. reinhardtii thylakoid membranes was used to isolate chlorophyll-protein complexes without chlorophyll (Chl) release in order to examine lipid species bound to these complexes. The four complexes obtained were shown to be the PSI complex, the PSII core complex and the two groups of the light-harvesting complex of PSII by analyses of 77-K emission spectra of Chl fluorescence and of subunit compositions. Lipid analysis of Chl-protein complexes in the parent revealed the localization of SQui-acyl2Gro in the PSII core complex and the two groups of the light-harvesting complex of PSII, but not in the PSI complex. These results suggest that SQui-acyl2Gro is responsible for PSII activity by associating with the core and light-harvesting complexes of PSII.

Animals↗
PubMed1995

Isolation and characterization of mutants affected in lipid metabolism of Chlamydomonas reinhardtii.

Two mutants affected in lipid metabolism of Chlamydomonas reinhardtii were isolated by treating cells with ultraviolet light. Both mutants showed high chlorophyll fluorescent yields, as compared with parents, and were designated as hf-2 and hf-9 (for high fluorescence). hf-2 was shown to be defective in the synthesis of a chloroplast-specific lipid, sulfoquinovosyl diacylglycerol. hf-9 was shown to be defective in desaturation at the omega 6 position of fatty acids of monogalactosyl diacylglycerol, digalactosyl diacylglycerol, sulfoquinovosyl diacylglycerol and phosphatidylglycerol. The mutants exhibited alterations in photosynthetic activity and chloroplast ultrastructure.

Animals↗
PubMed1995

Assessment of coronary artery distensibility by intravascular ultrasound. Application of simultaneous measurements of luminal area and pressure.

BACKGROUND: Atherosclerotic change in the coronary artery is associated with an impaired vessel wall distensibility. However, there are few data regarding the relation between vessel wall morphology and distensibility. Therefore, with intravascular ultrasound, we assessed coronary artery distensibility in angiographically normal coronary segments of humans. METHODS AND RESULTS: Data were analyzed at 35 angiographically normal coronary sites where circumferential or noncircumferential lesions were demonstrated by ultrasound in 22 patients (mean age, 55 years). After intracoronary injection of 500 micrograms nitroglycerin (NTG), coronary luminal area was measured with intravascular ultrasound (30 MHz, 3.5F to 4.3F, 1800 rpm). Intracoronary pressure was simultaneously measured with a 2F micromanometer-tipped catheter located at the left main coronary artery. The coronary distensibility index was calculated as 10-fold the ratio of luminal area change to intracoronary pressure change during a cardiac cycle. Another pressure-independent vascular stiffness index, beta, was derived by the following formula: beta = [ln(SBP/DBP)]/(dD/diastolic mean diameter), where SBP is systolic intracoronary pressure, DBP is diastolic intracoronary pressure, and dD is the difference between systolic and diastolic diameters. At the sites where luminal areas were measured, thickness of intima-media complex, defined as the distance between the intimal leading edge and the adventitial leading edge, was determined as an index of the severity of atherosclerosis. In seven segments, distensibility index was determined before and after NTG injection to examine the effect of NTG on coronary distensibility. In all examined sites, including circumferential and noncircumferential lesions, the luminal area was 12.6 +/- 5.0 mm2 during systole and 11.6 +/- 4.6 mm2 during diastole, and the calculated coronary distensibility index ranged from 0 to 0.83 mm2/mm Hg. The thickness of the intima-media complex ranged from 0.12 to 1.30 mm, suggesting the presence of various grades of atherosclerosis even in the absence of angiographic lesions. There was a poor inverse correlation between thickness of the intima-media complex and distensibility index (r = .19, y = -0.17x + 0.41, P = .29). However, when noncircumferential lesions were excluded for evaluation, there was a significant inverse correlation between them (r = .58, y = -0.50x + 0.72, P < .01). Under these conditions, the thickness of the intima-media complex also correlated with the value of beta (X10(-1), which ranged from 0.28 to 3.99 (r = .70). After NTG injection, coronary distensibility increased by an average of 71% in the segments with a thin intima-media complex, whereas it did not substantially change in those with a relatively thick intima-media complex. CONCLUSIONS: These results suggest that coronary distensibility is impaired in the coronary sites accompanying occult atherosclerosis, none of which can be detected by the conventional angiography. NTG can augment coronary distensibility in the segments without a markedly thickened intima-media complex. We suggest that thickness of the intima-media complex can contribute to determining the coronary distensibility in clinical settings.

Adult↗
PubMed1995

Expression of the Escherichia coli fabA gene encoding beta-hydroxydecanoyl thioester dehydrase and transport to chloroplasts in transgenic tobacco.

The fabA gene of Escherichia coli encodes beta-hydroxydecanoyl thioester dehydrase (HDDase), a pivotal enzyme in the biosynthesis of the unsaturated fatty acid cis-vaccenic acid, through the anaerobic pathway. This enzyme is specific to bacterial fatty acid biosynthetic pathways, although other enzymes for fatty acid synthesis are very similar in plants and bacteria. We constructed chimaeric plant expression vectors, pfab21 and pfab22, carrying the fabA gene under the transcriptional control of the cauliflower mosaic virus (CaMV) promoter of 35S RNA. In pfab21, fabA was placed directly under the control of the CaMV 35S promoter; whereas in pfab22, the DNA sequence coding for the chloroplast-targeting transit peptide (TP) of the pea ribulose-1,5-bisphosphate carboxylase (RuBisCo) small subunit was fused to the fabA gene in order to allow transport of HDDase to the chloroplast, the organelle responsible for de novo fatty acid biosynthesis in plants. Transgenic plants of Nicotiana tabacum were obtained by Agrobacterium-mediated transformation with pfab21 or pfab22. Expression of fabA transcripts of sizes expected from the chimaeric constructs was shown by RNA blot hybridization. The HDDase protein derived from pfab22 was correctly processed and transported to chloroplasts in transformed plants. The enzymatic activity of HDDase was also detected in chloroplasts isolated from the transformants derived from pfab22 (but not pfab21) and in total leaf protein of all transformants. However, no significant changes were observed in the fatty acid compositions, including cis-vaccenic acid, of leaf chloroplasts and self-fertilized seeds. These results are discussed in relation with the possible structural organization of plant fatty acid synthase.

Base Sequence↗
PubMed1995

[Analysis of p53 expression and DNA ploidy pattern in esophageal cancer].

DNA ploidy pattern analyzed by cytofluorometry and p53 protein expression using immunohistochemical method were studied in 35 cases of esophageal cancer. p53 protein were positive in 19 cases (54%), and DNA aneuploidy pattern were detected in 26 cases (74%). There was no relationship between DNA ploidy pattern or p53 expression and clinico-pathological factors. DNA aneuploidy or p53 positive cases were significantly poor prognoses in five-year survival rate. DNA aneuploidy and p53 positive cases were worst in four groups. It is effective for evaluation of biological malignancy and detection of post operative schedules to study not only clinico-pathological factors but also DNA ploidy pattern and p53 expression in esophageal cancer.

DNA, Neoplasm↗
PubMed1995

Overexpression and localization of cyclin D1 mRNA and antigen in esophageal cancer.

We examined the expression of cyclin D1 mRNA in two human carcinoma cell lines (A431 and TT) and 17 specimens of esophageal cancer with in situ hybridization. Cyclin D1 mRNA was overexpressed in the cytoplasm of cancer cells that showed cyclin D1 gene amplification by Southern blot hybridization. Cyclin D1 antigen was overexpressed in the nucleus of these cancer cells. The distribution of cyclin D1 mRNA-positive cells was similar to that of cyclin D1 antigen-positive cells in the cancer tissues. We then attempted to correlate overexpression of cyclin D1 antigen and prognosis, by using 55 formalin-fixed, paraffin-embedded specimens of esophageal cancer. The overall 5-year survival of patients with strongly staining tumors was significantly lower than that of patients with weakly or nonstaining tumors (7 versus 59%; P < 0.01). There was no significant correlation between cyclin D1 expression and other clinicopathological factors. These results suggest that cyclin D1 may play an important role in carcinogenesis and that cyclin D1 overexpression may be a useful prognostic factor in esophageal cancer.

Base Sequence↗
PubMed1994

Transcription of the faoAB operon which encodes the HDT multienzyme complex involved in fatty acid beta-oxidation in Pseudomonas fragi B-0771.

Transcription of the two clustered genes, faoA and faoB, for the multienzyme complex for fatty acid beta-oxidation (HDT) from the Gram-negative bacterium, Pseudomonas fragi, was investigated. Northern blot hybridization and primer extension analysis indicated that these genes comprised an operon, giving a 3.6 kb mRNA. Transcription of the 3.6 kb faoAB mRNA was induced by palmitic acid. Using the lacZ gene as a reporter gene for a promoter activity search, the essential region for induction of the faoAB gene transcription by palmitic acid was mapped at the 331 bp region just upstream of the transcription initiation site. Deletion of the 136 bp SalI-NheI fragment just downstream of the transcription initiation site caused the constitutive expression of the faoA-lacZ fusion protein in P. fragi, suggesting that there is a regulatory element interacting with the transcription repressor.

Base Sequence↗
PubMed1994

Intratracheal pulmonary ventilation (ITPV): control of positive end-expiratory pressure at the level of the carina through the use of a novel ITPV catheter design.

A new mode of pulmonary ventilation called intratracheal pulmonary ventilation (ITPV) was studied. Briefly, a continuous flow of air/oxygen is introduced through a small catheter, the tip of which is positioned at the carina, with a diffuser mounted at its distal end. A timed expiration valve, when closed, provides for inspiration; when open, it provides for expiration. The system as first described had a potential for significant back pressure at the level of the carina, which was more at rapid gas flows and with smaller endotracheal tubes. We have now mounted a venturi on the tip of the catheter (reverse thrust catheter [RTC]) that avoids back pressure, and which facilitates expiration. At respiratory rates from 10 to 120/min, the ITPV system with the RTC maintained end-expiratory pressure at the level of the carina at, or near 0 cm H2O. Compared to conventional mechanical ventilation, at identical respiratory rates, this system reduced tidal volume by one half at the lowest respiratory rates, and by as much as two thirds at the highest respiratory rates, with a proportional decrease in peak inspiratory pressure. ITPV has the smallest minute volume ventilation of any conventional or nonconventional mode of pulmonary ventilation.

Animals↗