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Biomedical subjects

N Sakamoto

Publications and source records attributed to N Sakamoto.

At least 91 records · Page 5Linked to original sources
PubMed1999

The effect of diet on blood vitamin K status and urinary mineral excretion assessed by a food questionnaire.

To assess Vitamin K (VK) status by food questionnaire, healthy young males (32) and females (9) were given a food list of 50 VK rich foods (identified in the 4th edition standard tables of food composition in Japan). After checking the food names and approximate amount eaten for 7 days, early morning blood and urine samples were collected. Prothrombin and hepaplastin was tested and plasma protein induced by VK absence factor II (PIVKA-II), osteocalcin, and calcium, phosphorous and magnesium in plasma and urine were determined. Participants who have a habit of eating natto, a traditional Japanese food very rich in Vitamin K, VK were excluded, and lowest and highest VK consumers were compared (males; lowest 7 vs. highest 7, females; 3 vs. 3). Plasma PIVKA-II levels, and urinary calcium and magnesium excretion of the lowest was significantly higher, but urinary phosphorus was lower, than that of the highest in females. In the natto eaters, daily mean VK intakes and hepaplastin test results of natto eaters were significantly higher, but urinary calcium excretions were lower than that of non natto eaters in males. These results suggest that Daily VK intake estimated from a questionnaire, is well related to real VK status, and also that natto is a good dietary source of vitamin K.

Adult↗
PubMed1999

Neural response of mechanoreceptors to acute inflammation in the rotator cuff of the shoulder joint in rabbits.

We examined with electrophysiological techniques the effects of experimentally induced inflammation on the mechanosensitive afferent units in the rotator cuff of the shoulder joint of 21 rabbits. We identified 21 mechanosensitive units belonging to group III. 12 units had mechanical thresholds of > 7.0 g and 9 units had thresholds of < 7.0 g. After injection of inflammatory agents, kaolin and carrageenan, into the joint space, ongoing afferent discharge rates increased in all units. The average discharge rate increased significantly from 7 imp/s to 15 imp/s after injection. 5 units had a decreased mechanical threshold after the injection. Acute inflammation seems to have an excitatory and sensitizing effect on the high- and low-threshold units in the rotator cuff.

Acute Disease↗
PubMed1999

[Clinicopathological analysis of transition zone cancer of the prostate: the clinical significance of coexistent non-transition zone cancer foci].

BACKGROUND: Dominant cancer of transition zone origin of the prostate (TZ cancer) has been frequently detected, because ultrasound-guided systematic biopsies have been generalized. In cases of TZ cancer, we attempted to determine clinical significance of coexistent non-TZ cancer foci. MATERIALS AND METHODS: Twenty cases with TZ cancer who underwent radical prostatectomy or cystoprostatectomy were clinicopathologically evaluated using step-sectioned specimens. RESULTS: In TZ cancer foci, there were extraprostatic extension in 5 cases (25%), seminal vesicle invasion in 2 cases (10%), positive surgical margin in 6 cases (30%) and bladder neck invasion in 4 cases (20%). The extraprostatic extension and the positive surgical margin occurred at the anterior or anterioapical portion of the prostate in all the cases. On the other hand, 17 (85%) had coexistent non-TZ cancer foci. In non-TZ cancer foci, there were extraprostatic extension in 3 cases (15%), seminal vesicle invasion in 1 case (5%) and positive surgical margin in 1 case (5%). The extraprostatic extension and the positive surgical margin occurred at the posteriolateral portion of the prostate in all the cases. In 3 cases a coexistent non-TZ cancer focus showed the extraprostatic extension, the seminal vesicle invasion or the positive surgical margin, although a TZ cancer focus were organ-confined. CONCLUSION: We should add attention to coexistent non-TZ cancer foci in TZ cancer cases. Particularly, we believe that pre-operative evaluation of non-TZ cancer foci is needed in TZ cancer cases of the candidates for nerve-sparing radical prostatectomy.

Aged↗
PubMed1999

Relationship between acute insulin response and vitamin K intake in healthy young male volunteers.

To evaluate the effects of vitamin K (VK) on pancreatic function, especially on acute insulin response, 25 healthy young male volunteers were given an oral load of 75 g of glucose, and their mean daily VK intake was estimated by a one-week food check list. After excluding low (<20) and high (> or =25) body mass index (BMI) subjects, the remaining 16 participants were divided into three semi-equal groups according to VK intake. Blood VK status of the low VK intake group tended to be poorer than that of the high intake group (median of 5 samples: prothrombin time; 12.5 vs 12.2s and protein-induced VK absence-factor-II; 23 vs 15 mAU/ml), but fasting plasma glucose status was not markedly different between both groups: [plasma glucose (PG); 87 vs 86 mg/dl, immunoreactive insulin (IRI); 6.7 vs 5.3 microU/ml, HbA1c; 4.8 vs 4.9%]. However, at 30 min after glucose loading, PG of the low VK intake group tended to be higher than those of the high intake group (160 vs 145 mg/dl) and IRI was lower (36.1 vs 52.3 microU/ml). Insulinogenic index (incremental IRI/incremental PG, 0-30 min) of the low VK intake group was significantly lower than that of the high intake group (0.4 vs 0.9). These results suggested that VK may play an important role on the acute insulin response in glucose tolerance.

Adult↗
PubMed1999

[Analeptics].

Explore the source record for details and available documents.

Adult↗
PubMed1998

Analysis of temporal expression pattern and cis-regulatory sequences of chicken pepsinogen A and C.

Three groups of pepsinogens exist in vertebrates, namely, pepsinogen A, pepsinogen C, and prochymosin, which are produced at different developmental stages. In the chicken, prochymosin is expressed only in the embryonic stage, while pepsinogens A and C are secreted from adult chicken proventricular (glandular stomach) mucosa. In order to understand the mechanism of transcriptional regulation of these genes, we have cloned the genes encoding chicken pepsinogens A and C and analyzed the sequences possibly involved in their regulation. 5'-Upstream sequences of both genes contain putative binding motifs for transcription factors such as GATA, Sox, and HNF-3 beta, which are expressed in the chicken gut epithelium. Moreover, we found seven putative binding motifs for human MZF-1 in intron 8 of pepsinogen A gene. These transcription factors may act as regulators of expression of chicken pepsinogen genes.

Amino Acid Sequence↗
PubMed1998

Preparation of a novel functional hydrogel consisting of sulfated glucoside-bearing polymer: activation of basic fibroblast growth factor.

Sulfated poly(glucosyloxyethyl methacrylate) [poly(GEMA)-sulfate] and its hydrogel were synthesized and evaluated to develop novel tissue regeneration assist devices. The poly(GEMA)-sulfate hydrogel was obtained by gamma-ray irradiation. Basic fibroblast growth factor (bFGF) was expected to be subsequently incorporated with hydrogel matrices and activated or released from the matrices. A sustained release of bFGF from the poly(GEMA)-sulfate hydrogel was not realized; however, bFGF from poly(GEMA)-sulfate hydrogel was effectively activated. Poly(GEMA)-sulfate hydrogels are thought to be potential component materials for a tissue engineering matrix.

Cell Adhesion↗
PubMed1998

Identification of a point mutation associated with a silent phenotype of human serum butyrylcholinesterase--a case of familial cholinesterasemia.

A point mutation which caused a silent phenotype of human serum butyrylcholinesterase (BChE) was identified in the DNA of a 47-year-old Japanese woman who visited our hospital complaining of hypertension. The propositus exhibited an unusually low level of BChE activity, whereas her younger sister and her daughter had intermediate levels of BChE activity and her elder sister a normal level. Immunologically, the amount of BChE protein in the serum of the propositus was normal. DNA sequence analysis of the propositus identified a point mutation at codon 199 (GCA --> GTA), resulting in a Ala --> Val substitution. This alteration is one downstream codon from the catalytic active site (Ser, 198). A family study showed her younger sister and her daughter to have the same mutation.

Blotting, Western↗
PubMed1998

Structure and function of a sea urchin orthodenticle-related gene (HpOtx).

Two distinct types of orthodenticle-related proteins (HpOtxE/L) have been implicated as transcription activators of the aboral ectoderm-specific arylsulfatase (Ars) gene. Here, we describe the structure of HpOtx gene and present evidence that mRNAs of HpOtxE/L are transcribed from a single HpOtx gene by altering the transcription start site and by alternative splicing. By transactivation experiments, we have also demonstrated that HpOtxL activates the Ars promoter in the gastrula-stage embryo.

Animals↗
PubMed1998

Effects of platelet release products on neutrophilic Fc gamma receptors.

Large and small macromolecular activators of phagocytosis from platelets (I-MAPP and s-MAPP, respectively), which function via the neutrophilic Fc gamma receptors (Fc gammaR) were refined from platelet release products by gel filtration and affinity chromatography with the use of an anti transferrin antibody column and the mechanism of phagocytosis activation was investigated. Flow cytometry revealed that 1-MAPP and s-MAPP did not increase the expression of neutrophilic Fc gammaRII (CD32) and Fc gammaRIII (CD16) antigens, whereas rosette formation of neutrophils with rabbit IgG-sensitized sheep erythrocytes (EA) in the presence of anti Fc gammaR antibodies suggested that both MAPPs increase the binding ability of Fc gammaRII. On the other hand, the enhancing effect of I-MAPP and s-MAPP on neutrophilic phagocytosis disappeared with the increase in phagocytosis by the phosphate-buffered saline control neutrophils when they were centrifuged with EA before incubation for phagocytosis. The enhanced phagocytosis, both by the two MAPPs and centrifugation, was canceled by treatment of the neutrophils with anti-CD32 Fab. The phagocytosis activatory effects of MAPP on neutrophils were canceled by anti-CD71 monoclonal antibody but not by transferrin.

Adult↗
PubMed1998

The incidence and characteristics of silent cerebral infarction in elderly diabetic patients: association with serum-soluble adhesion molecules.

The purpose of this study was to investigate the relationship between complications arising from silent cerebral infarction (SCI) and changes in the levels of serum-soluble adhesion molecules in 82 elderly diabetic patients aged 60 years and older. SCI was found in 43 % of the 82 patients, with incidence increasing in relation to age. The prevalence of SCI was higher in subjects with hypertension, poor metabolic control and increased fibrinolysis. The levels of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1) and E-selectin (sE-selectin) were higher in diabetic patients than in non-diabetic subjects (p < 0.05, p < 0.001, and p < 0.05, respectively). Also, sICAM-1 and sVCAM-1 were found at increased levels in diabetic patients with SCI compared to those without SCI (p < 0.01 and p < 0.05, respectively). In particular, the level of sICAM-1 was increased in patients with SCI due to perforating arterial occlusion, while the level of sVCAM-1 was increased in patients with SCI due to cortical arterial occlusion. However, no significant difference was found in sE-selectin levels. Overall average of the intima and media thickness (IMT) of the common carotid arteries increased with age. IMT proved to be greater in patients with SCI than in patients without SCI (p < 0.05), and showed a weak but significant positive correlation with sVCAM-1, while no correlation was found with either sICAM-1 or sE-selectin levels. In conclusion, measurement of serum adhesion molecules may be useful for diagnosing the early stages of brain damage and for prophylactic treatment which may prevent the onset or progression of SCI.

Aged↗
PubMed1998

Fusion variations of pancreatic ducts in patients with anomalous arrangement of pancreaticobiliary ductal system.

Fusion variations of the pancreatic ducts were studied to elucidate the significance of such variations. We classified structural fusion anomalies of the main and accessory pancreatic ducts on endoscopic retrograde cholangio-pancreatography (ERCP) in 37 patients with anomalous arrangement of the pancreaticobiliary ductal system (AAPB). The fusion variations of the pancreatic ducts were classified into five types: common, ansa pancreatica, branch fusion, looped, and separated. These fusion variations, except for common type, were found in 68% of the 37 patients with AAPB on ERCP. Fusion variations of the pancreatic ducts were very frequent (93%) in the 30 patients with congenital cystic dilatation of the common bile duct (CCD). The branch confluence fashion, in which the terminal bile duct communicated with a pancreatic duct branch, was found only in patients with cystic dilatation cyst of the CCD, and it appeared that cystic dilatation cyst of CCD might differ from spindle or cylindrical cyst originating from embryonic formation of an anomalous confluence. It was also suggested that in patients with fusion variations of the pancreatic ducts, the flow of pancreatic juice might be disordered, leading to the development of acute pancreatitis or pancreatic dysfunction. Consequently, it appears to be necessary to carefully examine patients with AAPB for the presence or absence of any fusion variations of the pancreatic ducts and to observe such patients with long-term monitoring by ERCP, and computed temography, and with pancreatic function tests.

Adult↗
PubMed1998

Effects of feedback inhibition on transit time in a linear pathway of Michaelis-Menten-type reactions.

An analysis of the effects of external and internal metabolites on the steady-state behavior of linear pathways comprising a sequence of three Michaelis-Menten-type reactions with and without a simple feedback inhibition (i.e. an interaction of an internal metabolite with the pathway) is performed with respect to the transit time tau by its formulation as rectangular-hyperbolic functions of the flux J, instead of direct expressions in terms of the external metabolite concentrations. For a given concentration of the external metabolite M1 (substrate of the pathway) or M4 (product of the pathway), the flux J has a lower value in the pathway with feedback inhibition than in the pathway without feedback inhibition. With variation in the M1 concentration the transit time tau shows a concave relationship with the flux J which is virtually identical for both pathways, yielding a minimum at a certain value of J. With variation in the M4 concentration the transit time tau monotonously decreases with higher value of J, and for a given value of J the feedback inhibition allows a lower transit time. This effect is enhanced with stronger feedback inhibition, and is in turn greatly reduced with higher values of total concentration and rate constants for the first enzyme in the pathway.

Enzymes↗
PubMed1998

Aromatic L-amino acid decarboxylase- and tyrosine hydroxylase-immunohistochemistry in the adult human hypothalamus.

The distribution of cell bodies immunoreactive for tyrosine hydroxylase and aromatic L-amino acid decarboxylase was studied in the adult human hypothalamus. Many neurons in the posterior (A11) and caudal dorsal hypothalamic areas (A13) as well as in the arcuate (A12) and periventricular (A14) zone were immunoreactive for the two enzymes, suggesting that they were dopaminergic. Numerous tyrosine hydroxylase-immunoreactive neurons, which were not immunoreactive for aromatic L-amino acid decarboxylase, could be seen in the paraventricular, supraoptic and accessory nuclei (A15) as well as in the rostral dorsal hypothalamic area. These were considered to be non-dopaminergic. Conversely, large numbers of small neurons immunoreactive for aromatic L-amino acid decarboxylase but not for tyrosine hydroxylase, were identified in the premammillary nucleus (D8), zona incerta (D10), lateral hypothalamic area (D11), anterior portion of the dorsomedial nucleus (D12), suprachiasmatic nucleus (D13), medial preoptic area and bed nucleus of the stria terminalis (D14). In the human hypothalamus, besides dopaminergic cell bodies, there exists a large number of tyrosine hydroxylase-only and aromatic L-amino acid decarboxylase-only neurons, whose physiological roles remain to be determined.

Aged↗
PubMed1998

Availability of software services for a hospital information system.

Hospital information systems (HISs) are becoming more important and covering more parts in daily hospital operations as order-entry systems become popular and electronic charts are introduced. Thus, HISs today need to be able to provide necessary services for hospital operations for a 24-h day, 365 days a year. The provision of services discussed here does not simply mean the availability of computers, in which all that matters is that the computer is functioning. It means the provision of necessary information for hospital operations by the computer software, and we will call it the availability of software services. HISs these days are mostly client-server systems. To increase availability of software services in these systems, it is not enough to just use system structures that are highly reliable in existing host-centred systems. Four main components which support availability of software services are network systems, client computers, server computers, and application software. In this paper, we suggest how to structure these four components to provide the minimum requested software services even if a part of the system stops to function. The network system should be double-protected in stratus using Asynchronous Transfer Mode (ATM) as its base network. Client computers should be fat clients with as much application logic as possible, and reference information which do not require frequent updates (master files, for example) should be replicated in clients. It would be best if all server computers could be double-protected. However, if that is physically impossible, one database file should be made accessible by several server computers. Still, at least the basic patients' information and the latest clinical records should be double-protected physically. Application software should be tested carefully before introduction. Different versions of the application software should always be kept and managed in case the new version has problems. If a hospital information system is designed and developed with these points in mind, it's availability of software services should increase greatly.

Computer Communication Networks↗
PubMed1998

Bradykinin B2-receptor-mediated modulation of membrane currents in guinea-pig cardiomyocytes.

1. In order to define the electrophysiological mechanism(s) responsible for bradykinin (BK)-induced positive inotropic and chronotropic responses in isolated guinea-pig atria, effects of BK on the membrane currents were examined in isolated atrial cells using patch clamp techniques. 2. BK (0.1-1000 nM) increased the L-type Ca2+ current (I(Ca)), which was recorded from enzymatically-dissociated atrial myocytes by the nystatin-perforated patch method, in a concentration-dependent fashion, and the calculated EC50 value for increasing I(Ca) was 5.2 nM. In conventional ruptured patch experiments, BK inhibited the muscarinic acetylcholine receptor-operated K+ current (I(K.ACh)) that was activated by the muscarinic agonist carbachol (1 microM) with an EC50 value of 0.57 nM. Both the increase in I(Ca) and the decrease in I(K.ACh) were blocked by HOE140, a selective bradykinin B2 receptor antagonist. 3. The BK-induced inhibition of I(K.ACh) was significantly attenuated by staurosporine and calphostin C, protein kinase C inhibitors. In addition, the I(K.ACh) inhibition by BK was also attenuated by the tyrosine kinase inhibitor genistein or tyrphostin but not by daidzein, an inactive analogue of genistein. However, neither protein kinase C inhibitor nor tyrosine kinase inhibitor affected the BK-induced increase in I(Ca). 4. In the presence and absence of muscarinic stimulation, BK prolonged the action potential recorded from the atrial cells in the current clamp mode. 5. We conclude that BK increases I(Ca) and decreases I(K.ACh) in atrial cells, resulting in positive inotropic and chronotropic responses in atrial preparations. Protein kinase C activation, and possibly tyrosine kinase activation, may be involved in the B2-receptor-mediated I(K.ACh) inhibition.

Action Potentials↗