Biomedical subjects

T Kanno

Publications and source records attributed to T Kanno.

At least 199 records · Page 11Linked to original sources

PubMed1997

Na+-dependent release of intracellular Ca2+ induced by purinoceptors in parotid acinar cells of the rat.

In rat parotid acinar cells, ATP caused a transient increase in the intracellular Ca2+ concentration ([Ca2+]i) in the absence of external Ca2+. The ATP-induced Ca2+ response was strongly suppressed by removal of external Na+. The sequence of potency in increasing [Ca2+]i was 3'-o-(4-benzoyl) benzoyl-ATP > ATP > uridine 5'-triphosphate (UTP). Adenosine, AMP, ADP or alpha,beta-metylene ATP did not cause an increase in [Ca2+]i. The 3'-o-(4-benzoyl) benzoyl-ATP-induced increase in [Ca2+]i was abolished by removal of external Na+, but the UTP-induced response was not. The threshold external Na+ concentration required for ATP- or 3'-o-(4-benzoyl) benzoyl-ATP-induced Ca2+ release was 10-20 mM. ATP but not UTP caused a rise in the intracellular Na+ concentration ([Na+]i). Ca2+ release stimulated by caffeine or treatment with ryanodine reduced the Ca2+ release evoked by ATP. These results suggest that ATP, acting through P2Z purinoceptors, causes Na+ entry by opening cation-permeable channels, and thereafter the increase in [Na+]i triggers Ca2+ release from ryanodine-sensitive stores. UTP, acting through P2U purinoceptors, causes Ca2+ release independent of external Na+.

Adenosine Triphosphate↗

PubMed1997

Photodynamic triggering of calcium oscillation in the isolated rat pancreatic acini.

1. Photodynamic agents, due to their photon-dependent selective activation, can selectively activate a number of physiological processes and may directly modulate signal transduction in a number of cells including pancreatic acinar cells. 2. Activation of the photodynamic agent sulphonated aluminium phthalocyanine (SALPC) triggered recurrent cytosolic calcium ([Ca2+]i) spiking in pancreatic acinar cells. 3. The photodynamically triggered calcium spiking could be blocked by phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor U73122, but not by phosphatidylcholine-specific phospholipase C inhibitor D609. 4. Removal of extracellular Ca2+ abolished spiking, as did 2-aminoethoxydiphenylborate (2-APB), an inhibitory modulator of IP3-mediated Ca2+ release from intracellular stores. 5. These data suggest that SALPC photodynamic action may permanently fix PI-PLC in an active conformation, and this produced recurrent [Ca2+]i spiking.

Animals↗

PubMed1997

Serum protein standardization project in Japan: evaluation of an IFCC reference material (RPPHS/CRM470) and establishment of reference intervals.

Reference preparation for proteins in human serum (RPPHS), also called Certified Reference Material 470 (CRM 470), was prepared by the international Federation of Clinical Chemistry (IFCC) and is intended to serve as a new international plasma protein reference material. It is now being introduced into Japan. RPPHS possesses many excellent properties, including safety, stability, and accuracy in value assignment. Moreover, the physicochemical properties of its proteins are identical to those of fresh serum, giving it immunochemical behavior that is commutable with that of existing reference materials and calibrators in given immunoassays. Reference intervals of 13 serum proteins were determined for the first time using nephelometry and a new working calibrator assigned from RPPHS, which seems certain to play a critical role in the global standardization of specific protein immunoassays.

Age Factors↗

PubMed1997

Soybean agglutinin binding as a useful prognostic indicator in stomach cancer.

Soybean agglutinin (SBA)-binding carbohydrate expression was studied immunohistochemically in 353 primary gastric carcinomas. The overall rate of positive SBA staining was 23% (81/353), and positive SBA staining was significantly correlated with tumor size, macroscopic tumor type, depth of invasion, lymph node metastasis, and venous invasion (P < 0.05). Moreover, patients with tumors that were immunoreactive for SBA demonstrated significantly higher survival (P < 0.01). From these findings we conclude that careful follow-up and intense postoperative therapy are required for patients with gastric cancers that lack immunoreactivity for SBA.

Adenocarcinoma↗

PubMed1997

A transcrista galli, translamina terminalis approach for highly placed basilar bifurcation aneurysms.

Surgery for highly placed basilar bifurcation aneurysms is one of the most difficult operations in neurosurgery. Specific surgical techniques have been developed including the temporopolar, zygomatic, transzygomatic subtemporal, transclinoid trans-seller transcavernous, and trans third ventricular approaches. The authors present some technical advances which have been developed for the transcristagalli translamina terminalis approach for the treatment of this aneurysm.

Aged↗

PubMed1997

Effects of carbachol and catecholamines on ultrastructure and intracellular calcium-ion dynamics of acinar and myoepithelial cells of lacrimal glands.

The current study was carried out to investigate autonomic nervous control of secretory functions in the lacrimal gland. To distinguish the difference between the responses to cholinergic and adrenergic agonists in acinar and myoepithelial cells in the lacrimal gland of guinea pigs, the morphological and functional responses to the agonists were examined by electron microscopy and by digital-imaging analysis of the intracellular concentration of Ca2+ ([Ca2+]i) using fluorescent Ca2+-indicators (Fura-2/AM and Indo-1/AM). In the resting state, exocytosis was rare, and the [Ca2+]i in acinar and myoepithelial cells was low (less than 300 nM). Stimulation with carbachol (CCh) induced a rapid rise in [Ca2+]i reaching a peak level followed by gradual decay and an appearance of many exocytotic figures. Approximately 4-8 s after an initial increase of [Ca2+]i, myoepithelial cells commenced contraction. Noradrenaline or adrenaline induced an increase in [Ca2+]i and exocytosis in acinar cells, but caused no [Ca2+]i increase in myoepithelial cells. In a Ca2+-deficient environment, the responses to CCh in myoepithelial cells and those to noradrenaline in acinar cells were inhibited, whereas the responses to CCh in acinar cells remained unchanged. Isoproterenol caused no effect on [Ca2+]i dynamics, although it occasionally induced exocytosis. Different cellular signaling pathways may be involved in the responses in acinar and in myoepithelial cells to different agonists. Lacrimation mechanisms are redundant.

Animals↗

PubMed1997

Classification and treatment of vertebral dissecting aneurysm.

BACKGROUND: For many years, dissecting aneurysms of the intracranial vertebral artery were believed to be quite rare. In recent years, because vascular disorders have been studied more thoroughly by three dimensional-computed tomography (3D-CT), angiographically and pathologically, these aneurysms are being reported with more frequency. METHODS: Among the 45 patients diagnosed to have aneurysms arising from the vertebral artery or its branches over a 20-year period, 16 had dissecting aneurysms. The authors present their therapeutic strategy for these patients. Surgery was performed in the 16 patients, the most common technique being clip-occlusion or trapping of the parent artery wherever feasible, in an attempt to optimize cerebral blood flow. The dissecting aneurysms of the vertebral artery were classified into two groups for the purpose of determining a therapeutic approach, namely unilateral and circumferential groups. In the unilateral group, the dissection seemed to involve only on one side of the vessel according to the conventional cerebral angiogram. These patients underwent surgical reconstruction of the vertebral artery by direct clipping. In the circumferential group, the dissection was all around the artery. Proximal clipping or trapping was performed in this group. RESULTS: In six out of eight patients with unilateral dissecting aneurysms, vascular reconstruction was possible by direct clipping. Of these six patients, the surgical outcome was considered excellent in four, fair in one, and one patient died of cardiac failure after 12 days as his preoperative morbid condition remained the same after surgery. Two other patients with unilateral dissecting aneurysms were treated with trapping technique and the surgical outcome was excellent in one patient and good in the other patient. Both patients resumed a normal social life. In five out of eight patients with circumferential dissecting aneurysms, trapping or proximal clipping was performed and the surgical outcome was excellent in two patients, good in one and fair in one patient. One patient with preoperative brain stem infarction died of aspiration pneumonitis after 8 months. Two patients who were noted to have an increase in the size of aneurysm during follow-up angiography underwent a craniotomy with clipping and wrapping of the aneurysm. There was a favorable surgical outcome in both patients. The remaining three patients had Grade IV subarachnoid hemorrhage (SAH) prior to surgery and at autopsy a disturbed vascular wall was detected. CONCLUSION: The authors' experience suggests that when surgically feasible, direct clipping is an effective alternative approach in the treatment of dissecting aneurysms of the vertebral artery in which blood flow in the parent artery is to be preserved.

Adult↗

PubMed1997

Operation on high-lying basilar bifurcation aneurysms.

BACKGROUND: The surgical approach to basilar bifurcation aneurysms is a complicated procedure, especially with those located high in the interpeduncular cistern. We have developed a surgical approach to these aneurysms involving only a small anterior temporal craniotomy and detachment of the zygomatic arch. METHODS: The skin incision is placed 5 mm below the inferior border of the zygomatic arch and 5 mm anterior to the tragus, extending on towards the eyebrow but well within the hairline. The zygomatic arch is detached on either side followed by a small temporal craniotomy exposing the anterior temporal lobe. The temporal lobe is retracted and the internal carotid artery, posterior cerebral artery, posterior communicating artery, and inferior aspect of the optic chiasma are exposed. RESULTS: We have performed a transzygomatic anterior subtemporal approach in 12 patients with high-lying basilar bifurcation aneurysm. Eight patients demonstrated a good recovery as per the Glasgow outcome scale and four patients had a moderate disability that correlated with a poor WFNS grade preoperatively. One patient had an oculomotor palsy and another experienced a small infarction postoperatively. CONCLUSIONS: This approach is a suitable procedure for high-lying basilar bifurcation aneurysms in the interpeduncular cistern and 1.2 cm above the clinoid process.

Aged↗

PubMed1997

Do reactive oxygen species underlie the mechanism of apoptosis in the tadpole tail?

Although "programmed cell death" has been postulated to underlie the mechanism for the disappearance of the tadpole tail, critical factors that trigger this phenomenon remain to be elucidated. To investigate the mechanism for the disappearance of the tail, changes in morphology, DNA status and the enzymes which metabolize reactive oxygen species were determined in the tail of Rana rugosa tadpoles. Histological examination revealed that apoptotic cell death was apparent in the tail myocytes during metamorphosis. Electrophoretic analysis of the tail DNA revealed a marked fragmentation. During the apoptotic changes, the activity of Cu/Zn-type superoxide dismutase (SOD) in the tail markedly increased with a concomitant decrease in its catalase activity. The apoptotic process was markedly enhanced by adding hydrogen peroxide (H2O2) and aminotriazole, a catalase inhibitor, to the medium. These observations suggested that apoptotic cell death in the tadpole tail might be triggered, at least in part, by a mechanism depending on active oxygen species, such as H2O2.

Amitrole↗

PubMed1997

Clinical study of 16 fully grown cerebral aneurysms.

The mechanismus of recurrence and enlargement of 16 cerebral aneurysms have been analyzed: 2 dissecting aneurysms, 6 fully grown aneurysms after neck clipping, 1 case after treatment with dome clip, 3 ruptured aneurysms that developed at the same sites and 4 cases that developed at other sites. From our investigation we concluded it was fundamentally important that the factor of the elastic lamina interna must attach in whole around the neck with precise neck clipping or adequate tight embolization involving positioning of the remaining elastica lamina interna in coil embolization.

Aortic Dissection↗

PubMed1997

Normal perfusion pressure breakthrough syndrome in giant arteriovenous malformations.

The treatment of large, high-flow cerebral arteriovenous malformations is one of the most difficult operations which neurosurgeons encounter because of the complex surgery and the post-operative effects on the brain. We have evaluated 10 patients with large, high-flow AVMs who underwent surgical resection. Patients were investigated with contrast-enhanced computed tomography and magnetic resonance imaging, 1231-IMP single photon emission computed tomography (SPECT) studies of cerebral flow and cerebral vasodilatory function, intraoperative Laser Doppler flowmetry (4 or 10 patients), and conventional angiography. The volume of the arteriovenous malformation nidi ranged from 32.8 to 210.5 cc. SPECT imaging performed on the first post-operative day showed marked hyperperfusion in the brain tissue surrounding the resected nidus, and these regions were normal on images on the 7th post-operative day. Laser Doppler flowmetry showed sudden, and marked increase in CBF immediately following placement of temporary clips on the main feeding artery. Angiograms done on 7-14 days following surgery showed a stagnating artery, fragile vessel, and a prolonged circulation time. Our results indicate that pre- and post-operative SPECT study, especially a dynamic SPECT study done on the first post-operative day, was the most useful examination for ascertaining the post-operative normal perfusion pressure breakthrough.

Adolescent↗

PubMed1997

Isolation and molecular cloning of epidermal- and hair follicle-specific peptidylarginine deiminase (type III) from rat.

Peptidylarginine deiminase (PAD) is a post-translational modification enzyme that catalyzes deimination of arginine residues of proteins in the presence of calcium ions. There are three types of PAD in rodent tissues: PAD types I, II, and III [Terakawa et al. (1991) J. Biochem. 110, 661-666]. Type III enzyme was detected only in the epidermis and in hair follicles. In this study, we have purified PAD type III from 2-day-old rat epidermis by a four-step procedure that included soybean trypsin inhibitor-affinity chromatography. The enzyme was purified about 600-fold from the crude extract and the recovery was 23%. The final preparation of the enzyme gave only a single protein band on SDS-PAGE and showed an apparent molecular weight of 76,000. Subsequently, we cloned and sequenced the full-length cDNA encoding rat PAD type III by reverse transcription-polymerase chain reaction (RT-PCR) using degenerate oligonucleotide primers designed from the internal amino acid sequences and by the rapid amplification of the cDNA ends method. The composite cDNA sequence contained a 5' untranslated region of 42 bp, an open reading frame of 1,995 bases that encoded 664 amino acids (Mr=75,036), a 3' untranslated region of 1,063 bp, and part of a poly(A)+ tail. The entire reading frame sequence of rat PAD type III showed 51% homology with that of rat PAD type II, and the C-terminal region is highly conserved between the two types. The cloned gene was expressed in Escherichia coli cells to produce PAD type III, which had not only enzymatic activity, but also immunoreactivity against specific antibodies toward PAD type II. Furthermore, the specific expression of the enzyme in the epidermis and hair follicles was confirmed by RT-PCR assays of mRNAs from several tissues.

Amino Acid Sequence↗

PubMed1997

2APB, 2-aminoethoxydiphenyl borate, a membrane-penetrable modulator of Ins(1,4,5)P3-induced Ca2+ release.

The effects of a novel membrane-penetrable modulator, 2APB (2-aminoethoxy diphenyl borate), on Ins(1,4,5)P3-induced Ca2+ release were examined. 2APB inhibited Ins(1,4,5)P3-induced Ca2+ release from rat cerebellar microsomal preparations without affecting [3H]Ins(1,4,5)P3 binding to its receptor. The IC50 value (concentration producing 50% inhibition) of 2APB for inhibition of Ins(1,4,5)P3 (100 nM) induced Ca2+ release was 42 microM. Further increase in the concentration of 2APB (more than 90 microM) caused a gradual release of Ca2+ from cerebellar microsomal preparations. Addition of 2APB to the extracellular environment inhibited the cytosolic Ca2+ ([Ca2+]c) rise in intact cells such as human platelets and neutrophils stimulated by thromboxane-mimetic STA2 or thrombin, and leukotriene B4 (LTB4) or formyl-methionine-leucine-phenylalanine (FMLP), respectively. 2APB inhibited the contraction of thoracic aorta isolated from rabbits induced by angiotensin II (AII), STA2, and norepinephrine in a non-competitive manner, but showed no effect on the contraction of potassium-depolarized muscle. 2APB had no effect on the Ca2+ release from the ryanodine-sensitive Ca2+ store prepared from rat leg skeletal muscle and heart. Although the specificity of 2APB with respect to the intracellular signaling system was not fully established, 2APB is the first candidate for a membrane-penetrable modulator of Ins(1,4,5)P3 receptor, and it should be a useful tool to investigate the physiological role of the Ins(1,4,5)P3 receptor in various cells.

Animals↗

PubMed1997

Simplified preparation of a refined milk formula comparable to rat's milk: influence of the formula on development of the gut and brain in artificially reared rat pups.

BACKGROUND: Milk formulas for artificially reared (AR) rat pups are mostly based on complex cow's milk products, prepared by laborious and time-consuming processes. The aim of this study was to develop a simplified procedure for preparing a refined formula and to examine its influences on gut and brain development. METHODS: The formula comprised a combination of purified cow's casein and whey proteins, five kinds of edible oil, minerals, and vitamins. Detailed analyses showed that the composition of macro- and micro-nutrients, osmolarity, and pH of the new formula closely resembled those of rat's milk. Rat pups, each with an intragastric cannula implanted at age 5 days, were artificially reared for the following 10-15 days. RESULTS: The body weight gain of AR pups matched that of mother-reared (MR) pups. Histoplanimetrical analyses showed that the small intestine in AR pups was more developed in relation to area of a transverse section, number and length of villi, and thickness of tunica muscularis than that of MR pups. Fat components in the formula influenced the fatty acid composition and the cholesterol-to-phospholipid ratio in the small intestinal microvillus membrane (MVM) of AR pups, but not the MVM fluidity. Brain weight was not significantly different between the two groups at age 15-20 days. CONCLUSION: This formula is useful for artificial rearing of rats and for identifying dietary components contributing to metabolic adaptation during the suckling period.

Animals↗

PubMed1997

A novel aspect of photodynamic action: induction of recurrent spikes in cytosolic calcium concentration.

Effects of photodynamic action of gadolinium porphyrin-like macrocycle B (PLMGdB) on cytosolic Ca2+ concentration, [Ca2+]c, was investigated in isolated rat pancreatic acini. The PLMGdB alone or light alone (2 min) had no effect on [Ca2+]c. Cell-bound PLMGdB upon brief (0.5-2.0 min) light activation triggered recurrent spikes in [Ca2+]c. At lower PLMGdB concentration (100 nM) the spikes continued during the whole period of monitoring [Ca2+]c. At a higher concentration of 500 nM, the spikes continued for the first 40 min, followed by a gradual increase in basal [Ca2+]c upon which smaller spikes were superimposed. At 1 microM, the spikes continued for the first 20 min, after that spiking gradually degenerated into a plateau phase. In many aspects, photodynamically triggered spikes resembled spikes generated by physiological concentrations of cholecystokinin. The spikes triggered by photodynamic action were likely to be the result of the ignition of a physiological "chain reaction", because functional inositol-1,4,5-trisphosphate (IP3) receptors were required for spiking to occur. Two-aminoethoxydiphenylborate, an inhibitory modulator of IP3-triggered Ca2+ release from intracellular stores, effectively inhibited photodynamically generated spikes. Therefore photodynamic action appears to be able to permanently transfix a physiological process, leading to long-lasting pharmacological or therapeutic effects.

Animals↗

PubMed1997

[A case of the tuberculous abscess in the abdominal wall].

A case of the tuberculous abscess in the abdominal wall is reported. A 84-year-old female was admitted to our hospital with evaluation of soft tumor at the left lower abdomen. She has a mass in the abdominal wall measuring 4 cm in diameter, and abscess in the abdominal wall was detected by ultrasonogram and CT. The confirmed diagnosis of abdominal wall tuberculosis was made by means of bacterial culture and polymerase chain reaction (PCR method) of the aspirated fluid from a mass. Multiple calcified lesions on the abdominal X-ray were seen, which were thought to past history of tuberculous peritonitis. Antituberculosis therapy of three-drug regimens was not effective. Four month later, resection of the abscess was then performed. Adhesion was demonstrated between greater omentum and peritoneum, therefore the abscess in the abdominal wall was considered to arise and advance directly from the abdominal cavity.

Abdominal Muscles↗

PubMed1997

A novel transcript encoding an N-terminally truncated AML1/PEBP2 alphaB protein interferes with transactivation and blocks granulocytic differentiation of 32Dcl3 myeloid cells.

The gene AML1/PEBP2 alphaB encodes the alpha subunit of transcription factor PEBP2/CBF and is essential for the establishment of fetal liver hematopoiesis. Rearrangements of AML1 are frequently associated with several types of human leukemia. Three types of AML1 cDNA isoforms have been described to date; they have been designated AML1a, AML1b, and AML1c. All of these isoforms encode the conserved-Runt domain, which harbors the DNA binding and heterodimerization activities. We have identified a new isoform of the AML1 transcript, termed AML1 deltaN, in which exon 1 is directly connected to exon 4 by alternative splicing. The AML1 deltaN transcript was detected in various hematopoietic cell lines of lymphoid to myeloid cell origin, as revealed by RNase protection and reverse transcriptase PCR analyses. The protein product of AML1 deltaN lacks the N-terminal region of AML1, including half of the Runt domain, and neither binds to DNA nor heterodimerizes with the beta subunit. However, AML1 deltaN was found to interfere with the transactivation activity of PEBP2, and the molecular region responsible for this activity was identified. Stable expression of AML1 deltaN in 32Dcl3 myeloid cells blocked granulocytic differentiation in response to granulocyte colony-stimulating factor. These results suggest that AML1 deltaN acts as a modulator of AML1 function and serves as a useful tool to dissect the functional domains in the C-terminal region of AML1.

Amino Acid Sequence↗

PubMed1997

Early experience with real-time CT-fluoroscopy for an intracranial lesion.

We have developed a real-time CT-fluoroscopy (CTF) system of which the initial trial was reported in 1993. This paper deals with the early clinical experience with this system. A third-generation scanner equipped with a slip-ring (Toshiba) was used. Images were reconstructed and displayed at a rate of 6/s with a 0.83-second delay time using a newly designed array processor. CTF was carried out in 12 cases (10 brain hemorrhages, 2 tumors). Good-quality fluoroscopic images were obtained in all cases. Real-time monitoring with CTF of needle placement and advancement was useful for accurate puncture needle biopsy and evacuation of the lesions. No serious complication was experienced in this series.

Biopsy, Needle↗