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Biomedical subjects

K Satoh

Publications and source records attributed to K Satoh.

At least 649 records · Page 36Linked to original sources
PubMed1994

Inhibitory effects of dantrolene on contractile responses in gastric smooth muscle of the rat.

Effects of dantrolene on contractions evoked by KCl, carbachol (CCh) and caffeine were studied in the circular smooth muscle of rat stomach. Dantrolene (10-100 microM) suppressed contractions evoked by KCl (40 mM) and CCh (1 microM), but not those induced by caffeine (3 mM) in physiological saline. After intracellular Ca stores were depleted by treatment with ryanodine (50 microM) plus caffeine (10 mM), or by repetitive applications of caffeine (10 mM) or CCh (0.1 mM) in the absence of extracellular Ca, combined application of KCl (150 mM) with Ca (2.5 mM) or CCh (1 microM) with Ca (2.5 mM) elicited contractions which were due to Ca influx. Nifedipine (10 microM) almost abolished the contractions induced by KCl, but only partially reduced the contractions induced by CCh. Dantrolene inhibited contractions induced by KCl with various concentrations of Ca (0.3-10 mM), and those induced by CCh with Ca (1-10 mM) in the presence of nifedipine. Dantrolene failed to inhibit the caffeine- and CCh-induced contractions depending on intracellularly stored Ca. In skinned muscle preparations, dantrolene had no effect on the contractions induced by Ca (6.3 x 10(-7M). These results suggest that dantrolene inhibits Ca influx through both nifedipine-sensitive and -resistant pathways of the plasma membrane but does not affect Ca release from intracellular stores and the contractile machinery in the circular smooth muscle of rat stomach.

Animals↗
PubMed1994

Vasodilator mechanisms of action of amrinone do not involve the opening of either ATP-sensitive or Ca(2+)-activated K+ channels.

Amrinone is more coronary vasodilatory than positive inotropic compared with other newer phosphodiesterase inhibitors. In order to explore possible involvements of ATP-sensitive K+ (KATP) and large-conductance Ca(2+)-activated K+ (KCa) channels in the vasodilator effect of amrinone, we investigated whether amrinone-induced vasodilation would be antagonized by glibenclamide, a blocker of KATP channels, or by charybdotoxin or tetraethylammonium, blockers of KCa channels. In isolated, blood-perfused canine papillary muscle preparations, the amrinone-induced increase in blood flow was not affected by glibenclamide given to support dogs. In canine large coronary arteries contracted with high (25 mM) KCl, amrinone-induced relaxation was not affected by glibenclamide, charybdotoxin and tetraethylammonium. These results suggest that the vasodilator mechanisms of amrinone do not involve the opening of either KATP or KCa channels.

Adenosine Triphosphate↗
PubMed1994

The importance of prevention of sinusoidal endothelial cell injury during cold preservation of liver graft.

We investigated adenosine triphosphate (ATP) synthesis, lipid peroxidation, and activities of radical scavenging enzymes in mitochondria, as well as the ultrastructural morphological changes during cold preservation of swine liver grafts (n = 6) with either Euro Collins (EC) or University of Wisconsin (UW) solutions. The liver, harvested by a standard procedure, was preserved in one of the solutions at 4 degrees C. The values of the total adenine nucleotide and mitochondrial respiratory control ratio (RCR), an index of ATP synthesis, decreased gradually for up to 24 hr during preservation with either of the two solutions and there was no statistical difference between them. Chemiluminescence of mitochondria, an index of lipid peroxidation, in the graft preserved with EC solution or UW solution decreased, and after 24 hr there was no significant difference between the two solutions. Activities of radical scavenging enzymes were well maintained in any of the two solutions. Transmission electron microscopy (TEM) findings showed that the sinusoidal endothelial cells were preserved much better with UW solution than with EC solution even after 12 hr preservation. We concluded that UW solution, more effective for the protection against injuries of the sinusoidal endothelial cells during cold preservation, leads to better results in clinical transplantation, but this solution has no protective effects on energy production, nor radical scavenging enzyme activities of mitochondria. In the maintenance of liver graft viability, protection of the sinusoidal microcirculatory disturbance is more important than that of the mitochondrial function.

Adenosine↗
PubMed1994

Induction and altered localization of 90-kDa heat-shock protein in rat kidneys with cisplatin-induced acute renal failure.

We purified 90-kDa heat-shock protein (HSP90) from murine brains and produced a specific antibody against the protein in a rabbit. This antibody cross-reacted with rat renal HSP90 on immunoblot analysis. Using the antibody, we observed serial immunohistochemical localizations of HSP90 in rat kidneys with cisplatin-induced acute renal failure. In normal kidneys, HSP90 was mainly localized in the cytoplasm of distal tubules and collecting ducts. Twenty-four hours after the cisplatin exposure, a rapid expression of HSP90 was observed in the cytoplasm of epithelial cells in the Henle's loops (especially at the luminal side), although there was little change in these cells on light microscopy. Degenerative changes of epithelial cells appeared in the S3 segment of proximal tubules on day 3, and epithelial cell regeneration in this portion was found from day 5. On day 5, HSP90 was markedly expressed in both the cytoplasm and the nucleus of epithelial cells in the S3 segment with a granular pattern. The induced HSP90 was then accumulated in the cytoplasm of these cells on day 7 and disappeared on day 14. Immunoblot analysis of isotonic buffer-extractable renal fractions showed that there was a rapid induction of HSP90 from day 1, and that the maximum induction of HSP90 in the extract at day 5 was 6-fold that of a control. These results suggest that HSP90 plays some role related to functional abnormalities of the Henle's loops at the luminal side, and in the regeneration of damaged cells in the S3 segment of proximal tubules, during the course of cisplatin-induced acute tubular injury.

Acute Kidney Injury↗
PubMed1994

Morphological aspects of the cytotoxic action of Helicobacter pylori.

OBJECTIVE: To morphologically investigate the cytotoxic action of Helicobacter pylori on gastric mucosal cells. METHODS: Twenty biopsy specimens were obtained from the antrum and greater curvature of the upper body of the stomach, and examined by electron microscopy to elucidate the process of mucus cell injury induced by H. pylori. RESULTS: Only H. pylori colonies in intimate contact with the mucosal cells caused various cell alterations, including loss of microvilli, mucus depletion, cell membrane injury and degeneration of the cytoplasm. In contrast, H. pylori that were not in contact with the mucosa had no effect on the surface mucus cells. CONCLUSIONS: The results of this study suggested the following mechanism of H. pylori-induced gastric mucosal injury. Intimate contact between H. pylori and the epithelial cell is necessary for cytotoxic action. During the process of cytotoxic action, degradation of the mucous gel layer and the glycocalyx are first caused by the proteolytic enzymes produced by H. pylori. Then the microorganism approaches the surface mucus cell, making intimate contact with the cell surface. Finally, H. pylori adheres directly to the cell membrane, effecting direct action of the toxins on the cell membrane. Subsequently, the degenerative changes induced destroy the cell membrane, resulting in degeneration of the cell itself.

Bacterial Adhesion↗
PubMed1994

Relationship between Helicobacter pylori and atrophic gastritis.

OBJECTIVES: To investigate the relationship between Helicobacter pylori and atrophic gastritis. DESIGN AND METHODS: The extent of atrophic gastritis was assessed endoscopically in 97 non-ulcer patients, and their H. pylori status was assessed by enzyme-linked immunosorbent assay. RESULTS: The prevalence of H. pylori infection was greatest in the early stages of atrophic gastritis. Small numbers of H. pylori-negative patients were identified at different stages during the extension of atrophic gastritis. CONCLUSIONS: H. pylori infection precedes the extension of atrophic gastritis, and a minority of patients with atrophic gastritis may never have been infected with H. pylori.

Adolescent↗
PubMed1994

[A 37-year-old man with memory loss, homonymous hemianopsia, and elevation of anti-herpes simplex virus antibody titer].

We report a 37-year-old man who presented memory loss, homonymous right hemianopsia, and elevation of anti-herpes simplex antibody titer. He had an auto accident in January 1992 in that the car he was driving slipped down a 3 m slope; his car was severely damaged, however, he himself was not injured. Shortly after this accident, he went out of his house less often than before, and he noted some difficulty in his vision. He changed his glasses twice, but his vision was unchanged. In July of 1992, he had an onset of difficulty in recent memory and disorientation to time. He also noted diplopia, and difficulty in seeing objects in his right visual field. He was admitted to our hospital on August 26 of the same year. General physical examination was unremarkable. On neurologic examination, he was alert but disoriented to time and place; calculation was also impaired. Mini-mental state examination was 18/30. He had no aphasia, apraxia, or agnosia. He showed a tendency to neglect his left side. Optic fundi and visual acuity were normal; right homonymous hemianopsia was present. Ocular movement was moderately restricted to most of the directions; pupils were isocoric and reacted to light promptly. He complained of diplopia in right gaze, and monocular nystagmus was induced in his right eye upon right lateral gaze. Trigeminal nerves appeared intact. Minimum left facial weakness was present. The remaining of the cranial nerves appeared intact. His gait was wide-based and tandem gait was impossible. Muscle strength was normal as was the muscle tone. Finger to nose and heel to knee tests were done normally.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Effect of shear stress on hemostatic regulation in endothelium].

The vascular endothelium plays a pivotal role in regulating the hemostatic system. Various cytokines, such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) are known to perturb endothelial cells to reduce antithrombogenicity. On the other hand, blood flow has been shown to affect the endothelium to maintain its antithrombogenicity under some levels of shear stress in the laminar flow system. We examined the role of hemodynamic forces on the vascular system under cytokine stimulation using a cone-plate type viscometer. Treatment of endothelial cells with either IL-1 beta or TNF-alpha under static conditions increased PAI-1, vWF and prostacyclin release, while t-PA secretion was unchanged. When cells were exposed to steady shear stress of 0, 6, 12, 18 and 24 dyne/cm2, the release of t-PA, t-PA-PAI complex and prostacyclin elevated with the increase of shear stress intensity, while a gradual decrease of total PAI-1 secretion was observed and vWF secretion was unchanged. On the contrary, active PAI-1 secretion was significantly decreased under the shear stress of over 18 dyne/cm2. Interestingly, cytokines, which did not affect t-PA secretion of resting cells, increased the t-PA secretion and had an additive effect on prostacyclin secretion with shear stress under the shear stress of over 18 dyne/cm2. PAI-1 elevation induced by cytokines was markedly abolished under the same shear forces. No additive effect was observed in the secretion of vWF. Thus, shear stress attenuates the alteration of the balance in the fibrinolytic and coagulation system induced by cytokines. These findings clearly indicate that hemodynamic forces play a crucial role in regulating the hemostatic activity in vivo.

Blood Coagulation↗
PubMed1994

[Surgical treatment of pancreatobiliary carcinoma in the elderly].

Between January, 1980 and December, 1992, 256 patients underwent resection of pancreatobiliary carcinoma. Sixty eight of these patients were more than 70 years old and are the subject of this review. The morbidity rate for pancreatic cancer patients undergoing pancreaticoduodenectomy was 50%. The five years survival rate was 15%. The morbidity rate for biliary cancer patients undergoing major resection was 40%. The five year survival rate was 40%. The data presented demonstrate that extended operation for pancreatic cancer should not be performed in the elderly patients but major resection for biliary cancer can be performed, even in elderly patients, with a low but somewhat increased mortality risk. Methods of estimating risk factor for elderly patients are required.

Aged↗
PubMed1994

Some personal comments on the Sydney system for the classification of chronic gastritis.

The Sydney system for the classification of chronic gastritis is a system for describing the histopathological findings of a biopsy specimen. It involves the analysis of two to four biopsies of the gastric mucosa taken from arbitrary sites, which, taken alone, are insufficient for extrapolation to the diagnosis of the whole stomach. The system seems to be useful as a computer-oriented method fo documenting the histopathological analysis of the two to four biopsy specimens obtained from the arbitrary sites in the antrum or corpus. One biopsy specimen is obtained from the anterior wall of the antrum, the other from the posterior wall. They would be better obtained from the lesser and greater curvatures, which areas would provide more accurate data concerning the antrum or body. While this may be invaluable for researchers with particular interests, it is quite valueless for the majority of clinicians who must diagnose and treat their patients. When a classification is made, its purposes should, firstly, be clear and definite. Secondly, the classification should be simple and easy to use. If a classification is effective, it will be widely used. However, in this field, it is almost impossible to achieve a classification that will fully satisfy all practitioners and researchers with different interests. The Sydney system alone is not sufficient for the classification of chronic gastritis. It is merely a system for describing the histopathological findings of biopsy specimens. It does not allow for an integrated diagnosis of chronic gastritis of the entire stomach.

Adolescent↗
PubMed1994

[Clinical studies on biapenem (L-627) in the pediatric field].

Biapenem (L-627) was given intravenously to 17 children with acute bacterial infections including 3 with purulent tonsillitis, 1 with bronchitis, 4 with pneumonia, 2 with sepsis, 3 with pyelonephritis, 2 with SSSS. (2 cases are omitted from evaluation because of Mycoplasma pneumonia and infectious mononucleosis). Daily dosages per kg bodyweight ranging from 18.3 to 60 mg were given in 3 divided doses per day for 4 to 6 days. Clinical responses were excellent in 12 (80%), good in 2 (13.3%), fair in 1 (6.7%) and poor in 0 (0%), with an overall efficacy rate of 93.3%. Good bacteriological responses were obtained in all of the 9 cases from which pathogens were identified. A side effect is observed in only 1 case with mild diarrhea. The above results suggest that L-627 is a useful new carbapenem derivative for the treatment of bacterial infections in children.

Bacterial Infections↗
PubMed1994

[Thallium-201 single photon emission computed tomography in the evaluation of therapeutic response for brain tumors].

To evaluate the effectiveness of radiation and chemotherapy of malignant brain tumors, 201TlCl-SPECT (Tl-SPECT) was compared with CT and MRI. The subjects were 14 patients with malignant brain tumors; 12 malignant astrocytomas, 1 medulloblastoma and 1 malignant lymphoma. Tl-SPECT was performed before and immediately after the therapy. On the Tl-SPECT, count ratio (Tl-index) of tumor to normal brain tissue was measured. To evaluate the size of tumor, CT or MRI was performed before and immediately after the therapy, and 1-2 months after the therapy. The change of Tl-index immediately after therapy was compared with the change of the size of tumor. Though the change of Tl-index did not correlate with the change of tumoral size immediately after therapy, it correlated with the change of tumoral size 1-2 months after the therapy, i.e., it was thought that Tl-index reflected the change of tumoral size 1-2 months after the therapy. Tl-SPECT will be feasible for the evaluation of the effectiveness of the therapy for malignant brain tumors, because it reflects the effectiveness of the therapy earlier than CT or MRI.

Adult↗
PubMed1994

[The two familial occurrence of von Hippel-Lindau disease].

Five cases of von Hippel-Lindau disease in two families were reported. In one family there were 2 cases in a mother (55 years old) and her daughter (26 years old) which had multiple hemangioblastomas in the optic nerve, cerebellum and spinal cord in each case. Retinal angioma appeared in the case of daughter, but not in the mother. In the other family there were 3 cases in a father (28 years old), his son (11 years old) and daughter (14 years old). All of them had retinal angioma and cerebellar hemangioblastoma. Two cases out of 5 cases in the two families were associated with abdominal organ diseases which were renal cell carcinoma in a case and pancreas cyst in the other. The familial occurrence of von Hippel-Lindau disease in Japan was recognized in 21 families with 103 cases including our cases. On the study of reported cases hemangioblastoma frequently occurred in multiple region such as cerebellum, medulla oblongata and frequently presented with renal cell carcinoma, pheochromocytoma and cyst in pancreas, kidney and liver. The location of hemangioblastoma and combined disease was similar in cases in each family. The age of onset of von Hippel-Lindau disease in the second generation was younger than that of the first generation.

Adolescent↗
PubMed1994

[anorexia nervosa; an association with certain types of soft tissue emphysema].

A 17-year-old female with anorexia nervosa developed pneumomediastinum, subcutaneous emphysema, retroperitoneal emphysema, interstitial pulmonary emphysema and epidural emphysema (epidural emphysema; air between the dura mater and the vertebral arch). She had no history of bronchial asthma. The mechanism was presumed to be weakness of the alveolar wall due to malnutrition, leading to rupture of alveoli, followed by air entering the interstitium and dissecting along perivascular sheaths (interstitial pulmonary emphysema) into the mediastinum. A further increase in mediastinal pressure may bring about opening of the fascial planes along great vessels and allow air to penetrate into subcutaneous tissues and the spinal canal. These types of emphysema have been reported in bronchial asthma cases and in those on positive pressure breathing. To our knowledge, there are no previous reports of anorexia nervosa associated with these phenomena.

Adolescent↗
PubMed1994

Pharmacological properties of the new stable prostacyclin analogue 3-Oxa-methano-prostaglandin I.

The pharmacological characteristics of the 3-oxamethano-prostaglandin I1 compound (+)-methyl [2-[(2R,3aS,4R,5R,6aS)-octahydro-5-hydroxy-4- [(E)-(3S,5S)-3-hydroxy-5-methyl-1-nonenyl]-2-pentalenyl]etho xy] acetate (SM-10902, CAS 139403-31-9), a novel stable analogue of prostacyclin and its free acid, SM-10906, were studied. SM-10902 was rapidly deesterified to its free acid in rabbit and human serum. SM-10902 and SM-10906 exhibited antiplatelet potency against ADP-induced aggregation in rabbit and human platelets. In the presence of diisopropyl fluorophosphate, an esterase inhibitor, the antiplatelet activity of SM-10902 was markedly reduced, to much less than that of SM-10906. SM-10906 inhibited platelet aggregation induced by various inducers in several species and enhanced the cyclic AMP (cAMP) level in human platelets. These activities were nearly equal to those of prostaglandin (PG) E1 and less than those of PGI2. SM-10906 relaxed isolated rabbit mesenteric and bovine coronary arteries, and elevated the cAMP level in bovine coronary arteries. SM-10906 given intravenously exhibited a sustained reduction in blood pressure based on vasodilation in ganglion-blocked, angiotensin II-supported rats. SM-10902 applied to the guinea-pig auricles increased the skin temperature, but SM-10906 and PGI2 showed no such effect. In conclusion, SM-10902, which is considered to be a prodrug of SM-10906, was suggested to exert its anti-platelet and vasodilator activities through the increase of cAMP. Since SM-10902 penetrates well into the skin, it may be useful as an external preparation to improve peripheral circulatory insufficiency.

Adenylyl Cyclase Inhibitors↗
PubMed1994

[Effect of epinephrine added to spinal anesthesia with lidocaine and tetracaine].

The effect of epinephrine added to the solution of lidocaine and tetracaine for spinal anesthesia was investigated in patients undergoing elective surgery of lower extremities. Thirty patients received 3ml of 2% lidocaine and 0.4% tetracaine and 30 patients received the solution with 0.1 mg of epinephrine added. A lumbar puncture was performed at the L2-3 interspace, using a midline approach with a 25-gauge spinal needle. Mean highest level of pinprick analgesia was Th6.1 without epinephrine and Th4.4 with epinephrine, and mean time for regression to Th10 was 2.3 hours without epinephrine and 3.6 hours with epinephrine. Progression of analgesia level was significantly faster and prolongation of duration was significant greater after adding epinephrine. No severe complications were found in any patients. We concluded that adding 0.1 mg of epinephrine to 3 ml of 2% lidocaine and 0.4% tetracaine could produce clinically useful prolongation of spinal analgesia.

Adolescent↗