Biomedical subjects

H Mukai

Publications and source records attributed to H Mukai.

At least 163 records · Page 9Linked to original sources

PubMed1992

[The role of insulin on renal sodium handling and sympathetic nerve activity in overweight normotensive subjects].

Recently, it was suggested that the role of hyperinsulinemia on the hypertensive mechanism of essential hypertension might be related to renal sodium handling and sympathetic nerve activity, especially in obese hypertensive patients. However, the interrelationship between insulin, obesity, renal sodium metabolism and sympathetic nerve activity in normotensive subjects (NT) still remains unclear. The present study, therefore, was undertaken to clarify the role of insulin on renal sodium handling and sympatho-adrenal function in overweight NT. The study consisted of 24NT, who were divided into two groups of twelve non-obese (NNT) and twelve obese (ONT) subjects. NNT was categorized as a body mass index (BMI) less than, and ONT as a BMI equal to or more than 25kg/m2. In the early morning, after overnight fasting, all subjects remained in a supine state and were examined for renal clearance test. During the two-hour clearance period, mean arterial pressure (MAP), heart rate (HR), endogenous creatinine clearance(CCr), urinary excretion of sodium (UNaV), fractional excretion of sodium (FENa), plasma immunoreactive insulin (IRI), plasma norepinephrine concentration (pNE), and plasma epinephrine concentration (pE) were determined. Although no significant difference was found in age, MAP, HR, pE, CCr or UNaV between the two groups, a significantly higher IRI (p less than 0.05) and lower FENa (p less than 0.05) were observed in ONT than in NNT. There was no significant correlation between IRI and UNaV, FENa or pE in ONT or in NNT. In addition, no significant correlation was shown between FENa and pNE or pE in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Medulla↗

PubMed1992

cDNA cloning of a neural visinin-like Ca(2+)-binding protein.

A 21,000-dalton Ca(2+)-binding protein (Walsh, M.P., Valentine, K.A., Ngai, P.K., Carruthers, C.A., and Hollengerg, M.D. (1984) Biochem. J. 224, 117-127) was purified from the rat brain and through the use of oligonucleotide probe based on partial amino acid sequence, cDNA clones were obtained from rat brain cDNA library. The complete amino acid sequence deduced from the cDNA contains 191 residues and has a calculated molecular mass of 22,142 daltons. There are three potential Ca(2+)-binding sites like the EF hands in the sequence. It displays striking sequence homology with visinin and recoverin, retina-specific Ca(2+)-binding proteins. Northern blot analysis revealed that the protein is highly and specifically expressed in the brain.

Amino Acid Sequence↗

PubMed1992

Clinical application of ultrasonic probes in the biliary and pancreatic duct.

The clinical use of an ultrasonic probe with the radial scan transducer in the biliopancreatic ducts is reported in 35 patients with biliopancreatic lesions, including 11 cases of bile duct and 5 of pancreatic carcinoma. Two approaches are available for the intraductal scanning of bile and/or pancreatic ducts. One is the percutaneous insertion via a percutaneous transhepatic biliary fistula established for cholangioscopy. The other approach is the transpapillary insertion of the probe via the working channel of the duodenoscope. Using both approaches, ultrasonographic images of the bile duct wall, pancreas head and neighboring major blood vessels could be observed clearly. The extent of bile duct and pancreatic carcinoma could also be visualized. We believe that intraductal scanning using ultrasonic probes is a promising method in the staging of biliopancreatic malignancy.

Bile Duct Neoplasms↗

PubMed1992

cDNA cloning of an aspartic proteinase secreted by Candida albicans.

cDNA of an aspartic proteinase secreted by Candida albicans No. 114 was isolated using the polymerase chain reaction (PCR). The primary structure of the enzyme was deduced from the nucleotide sequence of the cDNA and compared with the structures of Saccharomyces cerevisiae proteinase A and vacuolar aspartyl proteinase of C. albicans. The mature aspartic proteinase consisted of 341 amino acid residues, and was 17.6 and 15.3% identical with the proteinase A and the aspartyl proteinase, respectively. Two active aspartic acid sites and the amino acids near those sites were conserved in the aspartic proteinase. We also showed that there is another gene of aspartic proteinase than that of strain ATCC10231 reported by Hube et al (J. Med. Vet. Mycol. 29 (1991)) in the same C. albicans genome, both in that strain and in No. 114.

Amino Acid Sequence↗

PubMed1992

Distinct cellular expression of calcineurin A alpha and A beta in rat brain.

Specific polyclonal antibodies that distinguish the two distinct isoforms of the catalytic subunit of calmodulin-dependent protein phosphatase, calcineurin A alpha and A beta, were prepared, and the distribution of calcineurin A alpha and A beta in rat brain was studied using immunochemical and immunocytochemical techniques. Immunochemical measurement revealed that the regional distributions of the two isoforms differed and that A alpha was more abundant than A beta in the rat brain. The subcellular distribution patterns of both isoforms were similar. Both isoforms were highly enriched in cytosolic fractions, including the synaptosomal cytosol. Immunocytochemical analysis revealed that both A alpha and A beta immunoreactivities differed in regional and cellular localizations. These different patterns of expression suggest that the two isoforms of calcineurin A may each have specific functions in modulating neuronal activity in particular cell types.

Animals↗

PubMed1992

[Electrophysiologic effect of a new Ca(2+)-antagonist, TA-3090 on supraventricular tachycardia and conduction system].

We investigated the effect of a new Ca-antagonist, TA-3090 on supraventricular tachycardia (SVT) and conduction system, comparing it with the effect of Diltiazem Hydrochloride, in 11 patients who had paroxysmal SVT attacks. Seven of the 11 patients presented atrioventricular reentrant tachycardia (AVRT) via retrograde concealed conduction through an accessory pathway, and the others presented AV nodal reentrant tachycardia (AVNRT). After SVT was induced by means of programmed electrical stimulation at high right atrium, TA-3090 (0.1 mg/kg body weight) or Diltiazem (0.2 mg/kg) was administered intravenously for 3 minutes. TA-3090 terminated nine of 11 SVTs, while Diltiazem terminated four of 4 SVTs. On termination of SVT, both drugs interrupted A-H conduction during AVRT and the slow pathway during AVNRT. After TA injection, five of 11 SVTs could not be induced by programmed electrical stimulation, while two of 4 SVTs could not be induced after Diltiazem. In AVRT, three patients in which TA-3090 prevented SVT induction had a longer AV node effective refractory period than that of the others in which TA-3090 could not prevent SVT (330 +/- 46 vs 210 +/- 24 msec, p less than 0.01). However, SVT was induced more easily than before in three of the 11 patients treated with TA-3090 administration, and in one of the 4 patients treated with Diltiazem administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[A case of pulmonary blastoma].

A 45-year-old male with pulmonary blastoma was described. The patient suffered from headache and gait disturbance, and was diagnosed metastatic brain tumor. The histopathology of the removed tumor indicated metastasis from pulmonary blastoma. The pulmonary tumor, which had been detected on the chest x-ray film but misdiagnosed tuberculous lesion, was subsequently diagnosed pulmonary blastoma by TBLB. The patient underwent left upper lobectomy with mediastinal lymph node dissection, but died 12 months after the operation. To our knowledge, only 54 cases with pulmonary blastoma have hitherto been reported in the Japanese literature.

Brain Neoplasms↗

PubMed1992

[A case of idiopathic chronic interstitial nephritis progressed to renal failure without proteinuria nor hematuria].

A case of idiopathic interstitial nephritis who underwent to chronic renal failure without history of hematuria nor proteinuria is discussed. A 46 years old woman who showed gradually elevation of serum creatinine (1.3-2.5 mg/dl) admitted on our hospital. On occasions of pregnancy, health examination or hospital visit, she has never been pointed out hematuria nor proteinuria. Immunological disorders such as SLE, metabolic diseases, urinary tract obstruction and chronic urinary tract infection were excluded by the examinations after admission. Because of the severe enzymuria (beta 2-microglobulin, N-acetyl glucosaminidase), chronic interstitial nephritis was considered, and renal biopsy was performed. Severe tubulointerstitial changes were observed histologically, however, glomerular damage was comparatively mild. From these results, she was diagnosed idiopathic chronic tubulointerstitial nephritis. In this case, hematuria and proteinuria were absent until severe renal dysfunction. This may be caused by that inflammation was located to the tubulointerstitial area. The observation of enzymuria seemed to be important to diagnosis and follow-up of the interstitial nephritis.

Chronic Disease↗

PubMed1991

[Magnetic resonance imaging of the adrenal gland].

Adrenal imaging was performed using magnetic resonance (MR) was in 100 patients who had no clinical or biochemical evidence of adrenal abnormality and in 19 patients with 24 adrenal lesions (adenoma in 5, hyperplasia in 2, metastasis in 5, (lung cancer in 1, hepatoma in 4) adrenal cancer in 1, pheochromocytoma in 3, neuroblastoma in 3). Normal adrenal glands showed intermediate intensity between muscle and liver, and were detected in over 90% of cases on T1-weighted images (T1-weighted SE, inversion recovery). Adenomas and hyperplasias had the same intensity as normal glands. Medullary masses showed extreme hyperintensity on T2-weighted images and could be differentiated from cortical masses. Neuroblastomas were detected as hyperintense tumors with intratumoral hemorrhage and necrosis on T2-weighted MR images. Metastatic adrenal tumors from lung cancer were hyperintense on T2-weighted images, while metastasis from hepatoma showed low intensity on the same pulse sequence. In diagnosing adrenal metastasis, we must compare and contrast the tumor intensity and structure with those of the primary lesions. MR is considered a useful modality in characterizing adrenal tissue.

Adenoma↗

PubMed1991

Nonradioactive labeling with chemically modified cytosine tails by the polymerase chain reaction.

We developed a modified nonradioactive method for the detection of DNA. This method makes use of the polymerase chain reaction for preparation of probes; that is, a DNA fragment inserted in the polylinker region of an M13 or pUC vector is amplified with primers that have a modified cytosine tail at the 5' terminus (C-tailed primers). By this method, large amounts of labeled probes can be obtained easily. After hybridization, modified cytosine tails can be detected immunologically. DNA labeled by this method could be used in plaque hybridization. We could detect 0.05 pg of dot-blotted labeled DNA in 30 min with an enzyme-catalyzed chemiluminescence reaction.

Base Sequence↗

PubMed1991

cDNA cloning of a calcineurin B homolog in Saccharomyces cerevisiae.

We have isolated a cDNA clone encoding a homolog of mammalian calcineurin B (the regulatory subunit of calmodulin-dependent protein phosphatase) by screening a cDNA expression library of Saccharomyces cerevisiae with antiserum against bovine calcineurin B. The yeast calcineurin B homolog (YCNB) is composed of 175 amino acids with a calculated molecular mass of 19,639 daltons and contains four putative Ca(2+)-binding domains. The amino-acid alignment of YCNB with human calcineurin B demonstrates 53% sequence identity and 82% homology. Southern blot analysis indicates that the gene for YCNB is a single-copy gene. Thus, yeast calmodulin-dependent protein phosphatase apparently has a heterodimeric structure similar to that of the enzyme in mammalians.

Amino Acid Sequence↗

PubMed1991

cDNA cloning of a novel testis-specific calcineurin B-like protein.

A cDNA clone encoding a novel calcineurin B-like protein (CBLP) was isolated from a rat testis cDNA library by cross-hybridization with a calcineurin B cDNA probe. CBLP is composed of 176 amino acids and contains four putative Ca(2+)-binding domains. The overall predicted amino acid sequence homology between CBLP and calcineurin B is 82%. Northern blots showed that transcripts for CBLP are specifically and highly expressed in the testis.

Amino Acid Sequence↗

PubMed1991

[Renal sodium handling and renal dopaminergic activity in overweight normotensive subjects].

Recently, we reported that the blunted natriuretic ability related to an attenuation of renal dopaminergic activity might play an important role in the hypertensive mechanisms of overweight patients with essential hypertension. On the other hand, the interrelationships between obesity, blood pressure and renal sodium handling in normotensives (NT) have not been clear. The purpose of the present study is to reveal the role of renal dopaminergic activity on renal sodium handling in overweight NT. The study consisted of 52 hospitalized NT receiving a regular diet containing 200mEq of sodium, 75mEq of potassium, 2400kcal/day, who were divided into two groups of 31 non-obese (NNT) and 21 obese (ONT) subjects. NNT was categorized as the body mass index (BMI) less than, and ONT as the BMI equal to or more than, 25kg/m2. In the early morning, after overnight fasting, all subjects remained in a supine state and were examined for renal clearance. During the clearance period, mean arterial pressure (MAP), heart rate (HR), endogenous creatinine clearance (Ccr), urinary excretion of sodium (UNaV), fractional excretion of sodium (FENa) and of inorganic phosphorus (FEP) and urinary excretion of free dopamine (uDA) were determined. There were no significant differences in age, HR, Ccr or UNaV between the two groups. Higher MAP and lower FENa) were observed in ONT than in NNT, but the differences in these parameters were not statistically significant. However, FENa in ONT was significantly lower than in MAP-and Ccr-matched NNT. In addition, FENa correlated negatively with BMI in ONT, unlike in NNT. MAP was correlated positively with FENa, and a similar tendency was found between MAP and FEP in NNT, but not in ONT. On the other hand, there was no significant correlation between BMI and uDA in either NNT or ONT. This result was different from our previous data in patients with essential hypertension (EHT) in which BMI correlated with uDA positively in non-obese EHT and negatively in obese EHT. These findings suggest that blunted natriuretic ability may exist in ONT, and the role of renal dopaminergic activity related to the attenuated natriuretic ability in ONT may be less important than in obese EHT.

Adult↗

PubMed1991

Percutaneous fiberoptic angioscopy of the cardiac valves.

The feasibility of percutaneous translumial angioscopy of the cardiac valves was examined in eight patients with and in 11 patients without valvular disease. In eight of these patients, a guiding balloon catheter (9F) was introduced into the aortic root, a guide wire (0.014 or 0.025 inch) was introduced through the catheter into the left ventricle to prevent dislocation of the catheter, and a fiberscope (1.6 or 4.6F) was advanced to the distal tip of the catheter. The balloon was then inflated with carbon dioxide and was manipulated against the aortic valve; a body temperature heparinized saline was infused through the catheter for observation. Similarly, the balloon catheter was advanced transseptally into the left atrium for observation of the mitral valve in four patients. Also, the balloon catheter was advanced through the right femoral vein into the right atrium for observation of the tricupid valve in three patients. In patients with a normal aortic valve, the aortic cusp surface was smooth and white and the edges were sharp. They opened briskly during systole and coapted each other completely during diastole. In rheumatic aortic regurgitation, the cuspus were thick and blunt and their coaptation insufficiency was observed during diastole. In a patient with rheumatic AS, globular and yellow cusps were observed. Mitral valve leaflets were smooth and white in a patients without mitral valvular disease, while the leaflets were yellow, thick and irregular, and blood regurgitation from the left ventricle into the left atrium could be observed in two patients with rheumatic MSR. The process of opening and closure of a tricuspid valve was also observed in three patients without tricuspid valvular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

Structure-activity relationships of mammalian bombesin-like neuropeptides in the contraction of rat uterus.

Various peptide derivatives of the C-terminal decapeptide of gastrin releasing peptide (GRP-10) and neuromedin B (NMB), i.e., carboxyl terminal fragments, amino terminal fragments and substituted analogues, were chemically synthesized and the structure-activity relationships of the peptides were investigated by comparing their contractile activities on the rat uterus. Peptides with chain lengths of 8 and 9 amino acid residues from the C-terminus of GRP-10 and NMB, respectively, had considerable contractile activities. At position 6 of both decapeptides, Val seems to be more favourable than Thr for inducing contraction of the rat uterus. The substitution of His at position 3 and Leu at position 9 of GRP-10 by Leu and Phe, as in NMB leads to a decrease in activity. Moreover, Trp at position 4 and -Met-NH2 at the C-terminus are essential for activity. Furthermore, in order to characterize the bombesin-receptor profile of rat uterus, the inhibitory effect of two peptide antagonists, [D-Arg1, D-Pro2, D-Trp7,9, Leu11]-substance P and [Leu13-phi (CH2NH)-Leu14]-bombesin on the contraction of rat uterus were examined.

Amino Acid Sequence↗

PubMed1991

Calmodulin antagonists differentiate between Ni(2+)- and Mn(2+)-stimulated phosphatase activity of calcineurin.

The interaction of calmodulin antagonists with a phosphoprotein phosphatase, calcineurin, was investigated using para-nitrophenyl phosphate (pNPP) as a substrate. Calmidazolium, a potent calmodulin antagonist, inhibited the Ni(2+)-stimulated calmodulin-independent phosphatase activity to much the same extent as it did the Ca2+/calmodulin-stimulated activity. Other calmodulin antagonists, such as trifluoperazine, thioridazine, and W-7, also inhibited the Ni(2+)-stimulated phosphatase activity. On the other hand, calmidazolium only weakly and partially inhibited the Mn(2+)-stimulated phosphatase activity and the other calmodulin antagonists examined increased the Mn(2+)-stimulated activity, in the absence of calmodulin. With the addition of an equimolar amount, as to the inhibited holoenzyme, of the purified B subunit of calcineurin, the Ni(2+)-stimulated phosphatase activity recovered from 38 to 63% of the control level in the presence of 5 microM calmidazolium. When the amount of additional B subunit was increased, the phosphatase activity recovered to 94% of the control level, thereby implying that calmidazolium inhibits the Ni(2+)-stimulated phosphatase activity by interacting with the B subunit, in the absence of calmodulin. The Mn(2+)-stimulated phosphatase activity also recovered from the inhibition by calmidazolium, but a much larger amount of the B subunit was necessary for the recovery. These results indicate that the Ni(2+)- and Mn(2+)-stimulated activities of calcineurin are differentially affected by calmodulin antagonists and that the B subunit plays a crucial role in the expression of the Ni(2+)-stimulated phosphatase activity.

4-Nitrophenylphosphatase↗

PubMed1991

Structure and transforming potential of the human cot oncogene encoding a putative protein kinase.

A new transforming gene has been molecularly cloned from hamster SHOK cells transformed with DNA extracted from a human thyroid carcinoma cell line and named the cot (cancer Osaka thyroid) oncogene. cDNA sequencing disclosed that this oncogene codes for a protein with 415 amino acid residues, and computer matching showed 42 to 48% similarity matches with serine protein kinases. Its gene product was identified as a 52-kDa protein by transcription and translation in vitro. Expression of cot cDNA under transcriptional control by a retroviral long terminal repeat induced morphological transformation of NIH 3T3 cells as well as SHOK cells. Protein kinase activity associated with constructed p60gag-cot was detected by immune complex kinase assay with anti-gag antiserum. The cot oncogene was overexpressed in transformed SHOK cells and found to have a rearranged 3' end in the last coding exon, which probably resulted in a deletion and an altered C' terminus in the transforming protein. This DNA rearrangement appeared to have occurred during transfection of the tumor DNA into hamster SHOK cells and not in the original thyroid tumor.

Amino Acid Sequence↗

PubMed1991

Stereotactic Aqua-Stream and Aspirator in the treatment of intracerebral hematoma. An experimental study.

The efficacy of the Stereotactic Aqua-Stream and Aspirator (SAS&A) was experimentally investigated by using hematoma models in the test tube and in gelatin. Even a solid hematoma can be crushed by the water jet and aspirated easily. The greater the positive pressure of the water jet and the negative pressure of suction, the stronger the ability to remove clots. A water jet pressure of 10-20 kg/cm2 and a suction pressure of 100-200 mm Hg were sufficient to remove experimental clots from the test vessels. When the SAS&A was operated in the brain of dogs with a water jet pressure of 20 kg/cm2 and a suction pressure of 200 mm Hg, aspirated brain tissue was less than 15 mg/min in weight, and histological brain injuries were observed only in the area less than 2 mm from the window of the probe, indicating that the procedure with the SAS&A would be relatively atraumatic. We conclude that these observations indicate that the SAS&A can be safe and extremely useful for removal of hypertensive intracerebral hematomas, even in the acute stage.

Animals↗