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Biomedical subjects

K Kitamura

Publications and source records attributed to K Kitamura.

At least 433 records · Page 24Linked to original sources
PubMed1996

Superficial spreading type of early gastric cancer.

To determine the clinicopathological features of the superficial spreading type of early gastric cancer, which is defined as early gastric cancer in which the product of the longest diameter of the tumour and the diameter perpendicular to it is greater than 25 cm2, they were compared retrospectively with those of small-sized early gastric cancers, which are defined as tumours smaller than 2 x 2 cm2. The superficial spreading type accounted for 5.46% of all early gastric cancers. The distinguishing histopathological features of superficial spreading lesions were: a diffuse type of cancer, submucosal invasion and advanced lymph node involvement. Of the 32 patients with superficial spreading lesions, eight underwent an additional resection as a continuance of the first gastrectomy, because of an indistinct tumour margin. More extensive lymph node dissection was also performed on the group with superficial spreading lesions. There was no difference in 5 year survival rate between the two groups (superficial spreading type, 96.0% vs small-sized type, 95.1%). The most appropriate treatment for superficial spreading lesions is a wide surgical resection with extensive lymph node dissection.

Female↗
PubMed1996

Behaviour of adrenomedullin during acute and chronic salt loading in normotensive and hypertensive subjects.

1. Responses of adrenomedullin to acute and chronic salt loading were examined in normotensive and hypertensive subjects. 2. In the acute salt load study, isotonic saline (50 ml/kg for 1 h) was intravenously infused into nine normotensive subjects and 11 patients with essential hypertension. Plasma adrenomedullin was higher in hypertensive than in normotensive subjects but was unchanged by saline infusion in either the normotensive (before infusion, 2.4 +/- 0.2 fmol/ml; after infusion, 2.4 +/- 0.1 fmol/ml) or hypertensive (before infusion, 3.0 +/- 0.1 fmol/ml; after infusion, 2.9 +/- 0.2 fmol/ml) group, while renin was suppressed and atrial natriuretic peptide was markedly increased. Plasma endothelin was not affected either. 3. In the chronic salt load study, seven normotensive subjects and 23 patients with essential hypertension underwent two 7-day periods of 30 and 260 mmol/day sodium intake. Depending on the blood pressure change, 13 hypertensive subjects were classified as salt-resistant and 10 as salt-sensitive. Salt-sensitive hypertensive subjects had suppressed plasma renin activity even during low salt intake. Plasma adrenomedullin or endothelin were not affected by the salt intake changes in any group; however, the high salt intake increased atrial natriuretic peptide in all groups. 4. These data indicate that the circulating level of adrenomedullin is not changed by either acute or chronic salt loading in normotensive subjects and patients with essential hypertension.

Adrenomedullin↗
PubMed1996

Elevated plasma adrenomedullin level in hyperthyroidism.

Adrenomedullin is a recently discovered peptide that was first purified from phaeochromocytoma tissue and has marked vasodilatory activity, causing hypotension. In thyrotoxicosis, various haemodynamic changes are observed, including an increase in cardiac output and heart rate with a concomitant decrease in peripheral vascular resistance. To evaluate the mechanism underlying these haemodynamic changes in thyrotoxicosis, we measured the plasma adrenomedullin concentration in thyrotoxic patients with Graves' disease. The plasma concentration of adrenomedullin was elevated in hyperthyroid patients (14.7 +/- 5.7 pmol L-1) compared with euthyroid control subjects (5.6 +/- 1.3 pmol L-1) (P < 0.001). The correlation between the plasma adrenomedullin concentration and serum free thyroid hormone levels was marginally significant. The mean blood pressure was relatively low in the face of an elevated plasma adrenomedullin level. Adrenomedullin may therefore be responsible for the vasodilatation observed in thyrotoxicosis.

Adrenomedullin↗
PubMed1996

A gene for a dominant form of non-syndromic sensorineural deafness (DFNA11) maps within the region containing the DFNB2 recessive deafness gene.

Hereditary hearing loss is divided into two groups, syndromic and non-syndromic, the latter being more common and highly heterogeneous. Linkage analyses were performed on a Japanese family showing a dominant form of non-syndromic progressive sensorineural hearing loss. This gene (DFNA11) was localized within the region of chromosome 11q which contains the second gene for a recessive form of non-syndromic sensorineural hearing loss (DFNB2). Since it has been reported that another gene for dominant non-syndromic hearing loss (DFNA3) has been mapped to the same region as the first gene for recessive hearing loss (DFNB1), it is possible that different mutations in the DFNB2 gene may result in either dominant or recessive hearing loss.

Adolescent↗
PubMed1996

Crystallization and preliminary X-ray diffraction study of recombinant human eukaryotic initiation factor-4E.

Recombinant human eukaryotic initiation factor-4E (eIF-4E), purified by m7GTP-Sepharose 4B affinity chromatography, was used for crystallization. After concentration of the eIF-4E protein (7 mg/ml), the solution was subjected to crystallization by the hanging-drop method. Transparent needle crystals complexed with m7GTP were obtained from 50 mM 2-(N-morpholino)ethanesulfonic acid-KOH buffer (pH 6.5) containing 25% (w/v) polyethylene glycol 6000 and 0.2 M (NH4)2SO4. The crystals belong to tetragonal space group P4(1) or P4(3), of Z = 4, with unit-cell dimensions of a = 89.26, b = 89.26, and c = 38.51 angstrum, and diffract beyond 2.1 angstrum resolution. The Vm value was calculated to be 3.07 angstrum 3/Da, which indicates a solvent content of 59.9%.

Crystallization↗
PubMed1996

Angiotensin converting enzyme polymorphism is associated with severity of coronary heart disease and serum lipids (total cholesterol and triglycerides levels) in Japanese patients.

BACKGROUND: Much past research has concerned the relationship between coronary heart disease and the angiotensin converting enzyme (ACE) genotype, with many lines of evidence demonstrating polymorphism to be an independent risk factor for myocardial infarction. Interestingly, however, association of ACE polymorphism and severity of coronary artery stenosis according to racial background has recently been proposed. OBJECTIVE: To clarify the relationship between the ACE genotype and severity of coronary artery stenosis in Japanese patients. METHODS: In 36 consecutive patients undergoing coronary catheterization, comparative examination of coronary angiography findings with the ACE genotype was conducted. RESULTS: The severity of coronary artery stenosis indeed showed a relationship with the ACE genotype, with more severe coronary artery stenosis associated with the deletion (D) allele (P < 0.05). The serum lipids, total cholesterol and triglycerides levels, were also elevated in patients with the D allele (P < 0.05). CONCLUSION: We have provided further evidence that ACE polymorphism is associated with severity of coronary heart disease in a Japanese population. A possible relationship between serum lipids and the ACE genotype is also suggested.

Biomarkers↗
PubMed1996

Paraneoplastic pemphigus: report of a case.

A 56-year-old male with chronic lymphocytic leukemia developed extensive erosive mucocutaneous lesions with histologic acantholysis. Immunopathologic studies showed IgG deposition at the intercellular space, C3 deposition at both the intercellular space and the dermo-epidermal junction, and reactivity of the serum to rat urinary bladder epithelium. Autoantibodies in the serum to human epidermal proteins of 210 kD and 190 kD were shown by Western blotting and to proteins of 250 kD, 210 kD, and 190 kD by immunoprecipitation. All these data suggest the diagnosis of paraneoplastic pemphigus. Repeated plasmapheresis resulted in re-epithelialization of the mucocutaneous lesions and reduction in antibody titer from 1:1280 to 1:20. Although this mucocutaneous disease was established as a new autoimmune bullous disease by Anhalt et al. (1990), cases have rarely been reported from Japan. The present patient demonstrates the major characteristics of paraneoplastic pemphigus.

Autoantibodies↗
PubMed1996

Human T-lymphotropic virus type II in Japan.

Serum specimens were assayed for human T-lymphotropic virus type II(HTLV-II) infection in 1,500 individuals known to be seropositive for HTLV-I and 30,000 blood donors in Japan. All HTLV-I-positive individuals were negative for HTLV-II. However, one of the blood donors was clearly seropositive for HTLV-II. Further, the donor was shown to be positive for HTLV-IIb. Here we report at least one case with HTLV-II in Japan and discuss the origin of the infection.

Adult↗
PubMed1996

Multiple primary cancers with microsatellite instability: report of a case.

We report here a patient who developed a variety of tumors both synchronously and metachronously over a 2-year period. The involved organs were the uterus, ureter, and small and large intestines. The patient underwent open surgery 3 times and polypectomies 6 times. Postoperative histopathologic analysis showed 2 adenomas and 8 carcinomas. Genetic analysis revealed microsatellite instabilities at the tested loci in all 10 tumors, indicating that replication errors played an essential role in the tumorigenesis. Early identification of microsatellite instability could be useful for predicting development of additional primary cancers.

DNA, Neoplasm↗
PubMed1996

Clinical features of measles in immunocompromised children.

Measles is often fatal for immunocompromised hosts. Protective immunity against measles has been studied but is still not completely understood. Recently, five cases of measles were encountered in immunocompromised children. Two of these were allogeneic bone marrow transplanted cases (one common variable immunodeficiency and one severe aplastic anemia) in remission, one Wilms' tumor case in remission, one hepatoblastoma case after cytotoxic therapy at disease onset and one exaggerating hemophagocytic syndrome case with suppressed natural killer cell activity. Clinical symptoms, laboratory findings and the immunologic backgrounds of these five patients were investigated. One of the patients, an 8 year old boy with hemophagocytic syndrome, died of giant cell pneumonia which was confirmed in the section of necropsy lung specimen. Two other patients who received allogeneic bone marrow transplants were not immune to measles, despite their own and their donors' immunizations. Their clinical symptoms were rather severe but both patients recovered and have remained seropositive for as long as 13 months. This fatality from measles is the first reported in a patient with hemophagocytic syndrome. Suppressed natural killer cell activity may be a poor prognostic factor. Also, secondary immunization failure for measles can occur in bone marrow transplanted patients with rather severe clinical symptoms.

Adult↗
PubMed1996

Oestradiol-induced relaxation of rabbit basilar artery by inhibition of voltage-dependent Ca channels through GTP-binding protein.

1. Effects of oestradiol on the electrical and mechanical properties of the rabbit basilar artery were investigated by use of microelectrode, patch-clamp and isometric tension recording methods. 2. Oestradiol (10 nM-100 microM) relaxed arterial tissue pre-contracted by excess [K]o solution (30 mM) in a concentration-dependent manner. In Ca-free solution, histamine (10 microM) and caffeine (20 mM) each produced a phasic contraction, but oestradiol (10 microM) did not significantly affect their amplitude. 3. Oestradiol (< or = 100 microM) did not change the resting membrane potential of the artery whether in the presence or absence of TEA (10 mM). Action potentials observed in the presence of 10 mM TEA were abolished by oestradiol (100 microM). 4. Oestradiol (1 microM-100 microM) inhibited the voltage-dependent Ba current in a concentration-dependent manner. Oestradiol (100 microM) inhibited the Ba current observed in the presence of nicardipine (1 microM) more than that in the absence of nicardipine (to 31.0% vs 62.0% of control). 5. GTP gamma S (30 microM) in the pipette enhanced the inhibitory actions of oestradiol on the Ba current. On the other hand, with GDP beta S (1 mM) in the pipette, oestradiol failed to inhibit the Ba current. Pertussis toxin (PTX 3 micrograms ml-1) in the pipette totally prevented the inhibitory action of oestradiol on the Ba current. 6. Oestradiol (< or = 100 microM) had no significant effect on the outward K currents evoked by a membrane depolarization. 7. These results strongly suggest that oestradiol relaxes arterial tissue by inhibition of voltage-dependent Ca channels and that it inhibits both nicardipine-sensitive and -resistant Ca currents via a PTX-sensitive GTP-binding protein. The main target of oestradiol among the arterial Ca channels seems to be the nicardipine-resistant Ca channel, rather than the nicardipine-sensitive one.

Animals↗
PubMed1996

Analysis of the critical sites for protein thermostabilization by proline substitution in oligo-1,6-glucosidase from Bacillus coagulans ATCC 7050 and the evolutionary consideration of proline residues.

To identify the critical sites for protein thermostabilization by proline substitution, the gene for oligo-1,6- glucosidase from a thermophilic Bacillus coagulans strain, ATCC 7050, was cloned as a 2.4-kb DNA fragment and sequenced. In spite of a big difference in their thermostabilities, B. coagulans oligo-1,6-glucosidase had a large number of points in its primary structure identical to respective points in the same enzymes from a mesophilic Bacillus cereus strain, ATCC 7064 (57%), and an obligately thermophilic Bacillus thermoglucosidasius strain, KP1006 (59%). The number of prolines (19 for B. cereus oligo-1,6-glucosidase, 24 for B. coagulans enzyme, and 32 for B. thermoglucosidasius enzyme) was observed to increase with the rise in thermostabilities of the oligo-1,6-glucosidases. Classification of proline residues in light of the amino acid sequence alignment and the protein structure revealed by X-ray crystallographic analysis also supported this tendency. Judging from proline residues occurring in B. coagulans oligo-1,6-glucosidase and the structural requirement for proline substitution (second site of the beta turn and first turn of the alpha helix) (K. Watanabe, T. Masuda, H. Ohashi, H. Mihara, and Y. Suzuki, Eur. J. Biochem. 226:277-283, 1994), the critical sites for thermostabilization were found to be Lys-121, Glu-290, Lys-457, and Glu-487 in B. cereus oligo-1,6-glucosidase. With regard to protein evolution, the oligo-1,6-glucosidases very likely follow the neutral theory. The adaptive mutations of the oligo-1,6-glucosidases that appear to increase thermostability are consistent with the substitution of proline residues for neutrally occurring residues. It is concluded that proline substitution is an important factor for the selection of thermostability in oligo-1,6-glucosidases.

Amino Acid Sequence↗
PubMed1996

Inhibition of aldosterone production by adrenomedullin, a hypotensive peptide, in the rat.

Recently, we conducted in vitro studies and reported that adrenomedullin, a novel hypotensive peptide, inhibits aldosterone secretion by dispersed rat adrenal zona glomerulosa cells. To assess the physiological role of this inhibitory effect, we investigated the effect of adrenomedullin on aldosterone production in vivo. Male Sprague-Dawley rats were fed a normal sodium diet before the experiments. To begin the experimental procedure, we stimulated aldosterone production with a sodium-deficient diet or bilateral nephrectomy. After 3 days of sodium depletion or immediately after nephrectomy, we injected synthetic human adrenomedullin (2.5 nmol/kg SC) and repeated the injection three times at 6-hour intervals. Two hours after the last injection, the rats were decapitated and adrenal capsular tissue was collected. Adrenomedullin had no effect on plasma and adrenal aldosterone concentrations in the rats fed a normal sodium diet. Rats fed a sodium-deficient diet had significantly increased aldosterone concentrations in both plasma (4770.1 +/- 364.3 pmol/L) and adrenal gland (57.34 +/- 3.27 pmol per adrenal). Subsequently, injection of adrenomedullin significantly inhibited increases in concentrations (plasma, 2648.9 +/- 313.2 pmol/L; adrenal, 44.28 +/- 4.94 pmol per adrenal). In nephrectomized rats, increased aldosterone concentrations in plasma and adrenal gland were also significantly inhibited by adrenomedullin. In the second part of the study, plasma renin concentration, adrenal renin activity, plasma corticosterone concentration, serum potassium concentration, and plasma immunoreactive adrenomedullin concentration were examined for adrenomedullin effects. The first four were unaffected, and the last, plasma immunoreactive adrenomedullin, was elevated 15% to 30%. These in vivo results, together with our in vitro data, suggest that adrenomedullin may indeed play a physiological role in the control of blood pressure and electrolyte balance.

Adrenomedullin↗
PubMed1996

Plasma adrenomedullin concentration in patients with heart failure.

We measured plasma concentrations of adrenomedullin (AM), a novel bioactive peptide with potent vasodilator activity, in 21 patients with chronic congestive heart failure due to various heart diseases and compared them to levels in age- and sex-matched healthy subjects to examine the pathophysiological role of plasma AM in heart failure. In addition, the relationship between plasma AM and other hormones known to control the cardiovascular system was examined in these patients. The plasma AM level in the patients with heart failure was significantly (P < 0.01) higher than that in the control subjects (mean +/- SEM, 2.94 +/- 0.15 fmol/mL; n = 16), with a significantly (P < 0.05) higher concentration in patients in class III or IV (11.82 +/- 1.81 fmol/mL; n = 5) of the New York Heart Association functional classification than in those in class I or II (8.74 +/- 0.44 fmol/mL; n = 16). There were no significant correlations between plasma AM and catecholamine levels, whereas the plasma AM level was significantly correlated with the concentrations of plasma atrial natriuretic peptide (r = 0.58; P < 0.01), brain natriuretic peptide (r = 0.47; P < 0.05), and PRA (r = 0.77; P < 0.01) in the patients. Thus, the plasma AM concentration increased in proportion to the severity of heart failure along with the hormones known to modulate the development of congestive heart failure. The present findings suggest a possible role for AM as a circulating hormone participating in the defense mechanism against further deterioration of congestive heart failure in patients with heart disease.

Adrenomedullin↗
PubMed1996

Chronic effect of beta-adrenoceptor blockade on plasma levels of brain natriuretic peptide during exercise in essential hypertension.

Many factors have been reported to stimulate the release of brain natriuretic peptide (BNP) as well as atrial natriuretic peptide (ANP). In hypertensive patients, however, little is known about whether these factors differ from those in normotensive subjects or if they are influenced by antihypertensive treatment. We measured the plasma concentrations of BNP and ANP in 12 hypertensive patients and examined the chronic effects of beta-adrenoceptor blockade on BNP secretion during exercise with a bicycle ergometer. The exercise raised both plasma BNP and ANP with concomitant increases in systolic blood pressure, heart rate (HR) and plasma norepinephrine (NE) and epinephrine (Epi) before and after treatment. Before treatment, the changes in ANP and BNP correlated with that in HR (p < 0.05). After treatment 4 wk of treatment, the change in ANP correlated with those in NE and Epi as well as HR. Multivariate regression analysis indicated that only NE was a significant stimulus for ANP secretion during the treatment period. As for BNP, HR was the only significant stimulant for its secretion both before and after treatment. In essential hypertension, beta-adrenergic receptor blockade affected the factors stimulating exercise-induced ANP release but not those stimulating BNP release. BNP release, therefore, seems to be stimulated by similar but distinct factors from those that stimulate ANP release.

Adrenergic beta-Antagonists↗
PubMed1996

Antihypertensive therapy reduces increased plasma levels of adrenomedullin and brain natriuretic peptide concomitant with regression of left ventricular hypertrophy in a patient with malignant hypertension.

We investigated the potential role of increased plasma adrenomedullin and brain natriuretic peptide (BNP) levels in a patient with malignant hypertension. A 51-year-old man was admitted to our hospital with a chief complaint of visual disturbance. His blood pressure was 270/160 mmHg on admission. Papillary edema associated with retinal bleeding was observed. Echocardiography revealed marked concentric left ventricular hypertrophy with mild systolic dysfunction. Plasma levels of adrenomedullin and BNP were markedly elevated. Antihypertensive therapy reduced the plasma levels of adrenomedullin in association with a concomitant decrease in blood pressure. The plasma level of BNP also decreased and regression of left ventricular hypertrophy and normalization of left ventricular systolic function were observed. Our findings suggest that adrenomedullin may be involved in the defense mechanism against further elevations in blood pressure in patients with hypertension and that the plasma level of BNP may reflect left ventricular systolic dysfunction, left ventricular hypertrophy, or both, in patients with severe hypertension.

Adrenomedullin↗