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Biomedical subjects

S Kawano

Publications and source records attributed to S Kawano.

At least 109 records · Page 6Linked to original sources
PubMed1998

Effects of NSAIDs on proliferation of gastric cancer cells in vitro: possible implication of cyclooxygenase-2 in cancer development.

The roles of cyclooxygenase-2 (COX-2) in the development of gastric cancer are unknown. We investigated the effects of nonsteroidal antiinflammatory drugs (NSAIDs), which are specific and nonspecific inhibitors of COX-2, on proliferation of the gastric cancer cell lines KATOIII, MKN28, and MKN45. The protein level of COX-2 was examined in these cell lines by Western analysis, and mRNA levels of COX-1/2 by Northern analysis. These cell lines expressed comparable levels of COX-1 mRNA. However, mRNA and protein expression of COX-2 in these cell lines was different. MKN45 expressed higher levels of COX-2 mRNA and protein than KATOIII and MKN28. We also examined the effects of NS-398 and indomethacin, specific and nonspecific inhibitors of COX-2, on the increase in cell number and [3H]thymidine uptake of these cell lines. NS-398 and indomethacin suppressed proliferation of MKN45 cells that overexpressed COX-2, although they exerted minimal effects on proliferation of KATOIII and MKN28, which expressed lower levels of COX-2. These results are consistent with the hypothesis that COX-2 is expressed in certain groups of gastric cancers and is related to their cell proliferation. It was proposed that COX-2 plays an important role in development of gastric cancer cells. Furthermore, NSAIDs may exert antiproliferative activity against gastric adenocarcinomas that overexpress COX-2.

Adenocarcinoma↗
PubMed1998

Guidance in vitro of the pollen tube to the naked embryo sac of torenia fournieri

The precise guidance of the pollen tube to the embryo sac is critical to the successful sexual reproduction of flowering plants. We demonstrate here the guidance of the pollen tube to the embryo sac in vitro by using the naked embryo sac of Torenia fournieri, which protrudes from the micropyle of the ovule. We developed a medium for culture of both the ovule and the pollen tube of T. fournieri and cocultivated them in a thin layer of solid medium. Although pollen tubes that had germinated in vitro passed naked embryo sacs, some pollen tubes that grew semi-in vitro through a cut style arrived precisely at the site of entry into the embryo sac, namely, the filiform apparatus of the synergids. When pollen tubes were unable to enter the embryo sac, they continuously grew toward the same filiform apparatus, forming narrow coils. Pollen tubes selectively arrived at complete, unfertilized embryo sacs but did not arrive at those of heat-treated ovules or those with disrupted synergids. These results convincingly demonstrate that pollen tubes are specifically attracted to the region of the filiform apparatus of living synergids in vitro.

Journal Article↗
PubMed1998

Flow cytometric analysis of cell proliferation kinetics during duodenal ulcer healing.

Cell proliferation in the gastroduodenal mucosa of patients with duodenal ulcers was evaluated using flow cytometry. Forty patients with duodenal ulcers and 12 normal subjects were investigated. Biopsy samples were obtained during endoscopic examination and subjected to DNA analysis by flow cytometry. Thirty patients with duodenal ulcers were healed within 3 months with H2 blockers (tractable or responsive ulcers), whereas 10 patients did not respond to treatment (intractable ulcers). The percentage of cells at the DNA-synthetic phase, an index of cell proliferation, was constant in the adjacent duodenal mucosa 2 cm from ulcer margin and antral mucosa during duodenal ulcer healing. The index at the margin of tractable ulcers was elevated during the active stage (12.9 +/- 1.3), peaked during the healing stage (15.4 +/- 2.8) and returned to the same level at the scarring stage (10.9 +/- 2.0) as normal controls (10.3 +/- 1.7). However, the index was not elevated in intractable ulcers (10.3 +/- 1.7 in the healing stage) and was smaller than in tractable ulcers. These data indicate that augmented mucosal cell proliferation at the ulcer margin plays an important role in duodenal ulcer healing and intractable ulcers are characterized by an abnormal failure to accelerate DNA synthesis to achieve ulcer repair.

Adult↗
PubMed1998

Disturbed pyloric motility in Ws/Ws mutant rats due to deficiency of c-kit-expressing interstitial cells of Cajal.

Interstitial cells of Cajal (ICC) are believed to initiate the basic contractile activity of the gastrointestinal tract. Interstitial cells of Cajal express c-kit receptor tyrosine kinase and are deficient in Ws/Ws mutant rats with a small deletion of the c-kit gene. As Ws/Ws rats show remarkable bile reflux to the stomach, the contraction pressure of the pylorus was compared between Ws/Ws and control +/+ rats. The contraction pressure of the pylorus was measured using a microtransducer, which was inserted through a pin-hole in the anterior wall of the stomach under anesthesia. The magnitude of bile reflux was estimated by measuring the content of bile acids in the stomach. The c-kit messenger RNA-expressing cells were detected by in situ hybridization. Frequency and the maximum pressure of the contraction were comparable between Ws/Ws and +/+ rats, but the duration of the contraction was significantly shorter in Ws/Ws rats than in +/+ rats. The number of c-kit messenger RNA-expressing ICC in the pylorus of Ws/Ws rats was 1.7% that of +/+ rats. The bile reflux observed in Ws/Ws rats was attributed to the decrease in the duration of the pyloric contraction, which appeared to result from the deficiency of c-kit messenger RNA-expressing ICC.

Animal Feed↗
PubMed1998

Evaluation of the PyloriTek test for detection of Helicobacter pylori infection in cases with and without eradication therapy.

OBJECTIVE: The accuracy of the PyloriTek test (a 1-h rapid urease test) used after eradication therapy of Helicobacter pylori (H. pylori) has not been well clarified. This study was done to evaluate the accuracy of the PyloriTek test results for cases with and without eradication therapy, using culture and histology as gold standard methods, and to establish the suitable timing of the PyloriTek test after eradication treatment. METHODS: One hundred sixty-three patients undergoing upper endoscopy were randomly selected; 100 patients had not received eradication therapy and 63 had. Three biopsy specimens each were obtained from the gastric antrum and the body for examination by PyloriTek, culture, and histology. The absence of H. pylori was established with negative results from both culture and histology. RESULTS: In cases without eradication therapy, PyloriTek, correctly identified 66 of 67 H. pylori-positive cases and 30 of 33 H. pylori-negative cases, yielding 98.5% sensitivity and 90.9% specificity. In cases with eradication therapy, PyloriTek gave correct diagnoses in 10 of 17 H. pylori-positive cases and in 45 of 46 H. pylori-negative cases, for 58.8% sensitivity and 97.8% specificity. However, when PyloriTek was used more than 4 months after the end of eradication therapy, both the sensitivity and the specificity increased to 100%. CONCLUSION: Considering time and cost, the use of PyloriTek alone may be satisfactory for detecting H. pylori infection in cases without eradication therapy. When patients are examined more than 4 months after intervention, the use of PyloriTek alone may be sufficient for correctly diagnosing H. pylori infections.

Amoxicillin↗
PubMed1998

[Possibility of prevention of herpes zoster by use of varicella vaccine].

It has been considered that a decline in specific cell-mediated immunity (CMI) for the varicella-zoster virus (VZV) could be responsible for a high incidence of herpes zoster in the elderly. If the strength of CMI for VZV could be increased by immunization of the elderly with a varicella vaccine, herpes zoster might be preventable. We compared the CMI for VZV (using a lymphoproliferative assay and a varicella skin test) and VZV-IgG antibodies in serum before and after 2-3 months of vaccination in 15 subjects more than 40 years old. When the CMI for VZV was measured by the lymphoproliferative assay, a stimulation index (SI) of more than 2.0 was estimated to be positive in this study. The SIs (mean +/- SD) before and after the vaccination were 2.7 +/- 1.8 and 2.7 +/- 1.9, respectively, and no significant difference was noted. On the other hand, the diameter of erythema in the varicella skin test after the vaccination became larger than that before the vaccination in the 10 of 13 subjects. In addition, serum VZV-IgG antibodies increased after vaccination in 6 of 14 subjects. There were no obvious reasons for the discrepancy in the results of the lymphoproliferative assay and the varicella skin test. However, because of the poor response indicated by the assay, only one vaccination for the elderly might not be enough to increase the CMI for VZV. The appropriate age for vaccination should also be considered. Lastly, further investigation of the CMI for VZV before and after vaccination on larger scale is required.

Aged↗
PubMed1998

Cyclooxygenase-2 inhibitors suppress the growth of gastric cancer xenografts via induction of apoptosis in nude mice.

To clarify the role of mitogen-inducible cyclooxygenase (COX-2) in the development of malignant tumors, we investigated the effects of COX-2 inhibitors on the growth of gastric cancer xenografts in nude mice in vivo. MKN45 gastric cancer cells (5 x 10(6) cells/animal) that overexpress COX-2 were inoculated subcutaneously into athymic mice. NS-398, a specific COX-2 inhibitor, or indomethacin, a nonspecific COX-2 inhibitor, was administered orally to animals every day for 20 days. These drugs reduced the tumor volume significantly. Immunohistochemistry using bromodeoxyuridine, nick end labeling, and electron microscopy showed that NS-398 induced apoptosis in cancer cells in a dose-dependent manner and inhibited cancer cell replication slightly. Indomethacin also induced apoptosis and suppressed replication of tumor cells. There was a significant negative correlation between tumor volume and apoptotic cell number within the tumor. These results are consistent with the hypothesis that COX-2 inhibitors suppress growth of gastric cancer xenografts mainly by inducing apoptosis and suppressing replication of the neoplastic cells. It follows that COX-2 plays an important role in the development of gastric cancer.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Impaired peripheral vasoconstriction in response to alpha-adrenergic stimulation in patients with idiopathic hypertrophic cardiomyopathy.

Exercise hypotension has been documented in patients with hypertrophic cardiomyopathy (HCM). Some investigators reported that this is due to an inadequate increase of systemic vascular resistance during or after exercise. The aim of this study was to investigate the pathogenesis of limb vascular response abnormalities in patients with idiopathic HCM. Thirteen patients with HCM and 9 healthy controls were administered an endothelium-dependent dilator (acetylcholine), a direct smooth muscle dilator (nitroglycerin), an alpha-adrenergic stimulator (phenylephrine), and a beta-adrenergic stimulator (isoproterenol) by intra-arterial infusion. Peripheral vascular resistance was assessed by forearm plethysmography at rest and during each infusion to obtain the percentage change in vascular resistance. Isoproterenol, acetylcholine and nitroglycerin produced dose-related vasodilatation with no significant differences between HCM patients and healthy controls. The percentage increase in vascular resistance was significantly less in HCM patients than in healthy controls after phenylephrine infusions of 0.5 microg/min (155+/-38% vs 195+/-47%, mean+/-SD, p<0.05) and 1.0 microg/min (174+/-49% vs 238+/-65%, p<0.05). Vasoconstriction mediated by alpha-adrenergic receptors appeared to be impaired in the peripheral vasculature of patients with HCM.

Adrenergic alpha-Agonists↗
PubMed1998

Non-dipolarity of heart potentials estimated by magnetocardiography in normal subjects.

We studied non-dipolarity characteristics during ventricular excitation in normal adults and children by magnetocardiography (MCG) by recording magnetic field on the thorax. The source and currents of the electrical dipole from the onset up to 60 ms of ventricular excitation were analyzed in 16 adults and 5 children. A single equivalent current dipole (ECD) was estimated by Sarvas' formula for the sphere model at 1 ms intervals. The non-dipole value (NDV) was calculated from the magnetic field strength at each recording point and theoretically estimated by ECD, representing an index for the non-dipolarity. At 32-34 ms from the beginning of QRS, the mean NDV was a minimum in all subjects suggesting at least a non-dipole component during this period. High NDV (over 5%) were present in most subjects in both the early and late phase compared to this period. Thirteen of 16 adults had a high NDV in the early phase (9.3 +/- 3.0%, mean +/- SD) and all 16 subjects had a high NDV in the late phase (21.5 +/- 10.5%). All 5 children had high NDV in both the early (10.5 +/- 5.4%) and late phases (16.8 +/- 7.9%). A single ECD estimation by MCG showed a relatively low non dipolar component and MCG could be applied to the clinical evaluation of cardiac excitation in both normal and pathological conditions.

Adult↗
PubMed1998

Effects of propofol on a Ca2+-activated CI- current in rabbit ventricular myocytes.

Propofol is a widely used intravenous anesthetic, which is known to affect cardiac functions. Cardiac effects may be caused by direct actions on ion channels of the heart. While effects of propofol on several ion channels have been studied at the whole cell and single-channel levels, its effects, if any, on anion currents have yet to be examined. Effects of propofol on Ca2+-activated Cl- current (I(Cl(Ca))) were investigated in single myocytes isolated from rabbit ventricles by the whole-cell patch clamp technique at 36 degrees C. I(Cl(Ca)) was activated by perfusing internal solutions with 0.1 microM free Ca2+ in the absence and presence of 10 mM internal Na+, eliciting I(Ca)-dependent and -independent component, respectively. By the application of propofol (0.1-300 microM), I(Ca)-independent I(Cl(Ca)) was strongly inhibited in a dose-dependent manner with an IC50 of about 5 microM. The blocking effects of propofol were voltage independent. On the other hand, the I(Ca)-dependent component of I(Cl(Ca)) was little affected by propofol at concentrations of up to 50 microM. The outward Na+/Ca2+ exchanger current was also blocked by application of 5 microM propofol. We conclude that propofol inhibits cardiac I(Cl(Ca)) in rabbit ventricular myocytes, mainly the I(Ca)-independent component, at therapeutic concentrations. The inhibition may be due to block of a reverse mode of Na+/Ca2+ exchange current.

Action Potentials↗
PubMed1998

Changes in urinary excretion of deoxypyridinoline in tail-suspended rats: effects of a bisphosphonate, YH529.

Urinary excretion of deoxypyridinoline (D-Pyr) has been shown to be a useful marker for bone resorption. In this study, we investigated whether D-Pyr could be used to monitor the changes in bone resorption of the hind limb induced by tail-suspension. Male Wistar rats 5-weeks old were tail-suspended in a metabolic cage to unload the hind limbs. The control rats were not suspended. YH529 (YH), an inhibitor of bone resorption, or a vehicle (phosphate buffered saline=PBS) was administered daily starting 3 days before the commencement of tail-suspension. In the non-suspended rats receiving PBS, urinary excretion of D-Pyr did not show any significant change during the one-week experimental period. In the non-suspended rats receiving YH, D-Pyr excretion significantly decreased on day 5 and 7 when compared with that observed on day 0, in accordance with the systemic inhibition of bone resorption by YH. In the tail-suspended rats receiving PBS, D-Pyr excretion showed a tendency to increase on day 1, which is in agreement with our previous report that tail-suspension causes an early (on day 1 of suspension) and transient increase in bone-resorption of the hind limbs. In the tail-suspended rats treated with YH, the increase in D-Pyr excretion on day 1 was not observed, and a significantly lower excretion was noted from day 3 to 7 during the tail-suspension. It was suggested that D-Pyr excretion might reflect the transient increase in hind limb bone resorption induced by tail-suspension. As observed in-YH treated rats, D-Pyr excretion could serve as a good marker for the inhibition of systemic bone resorption.

Amino Acids↗
PubMed1998

[Acute myocardial infarction due to traumatic hemorrhagic shock with open fracture: a case report of staged amputation and CABG].

A 55-years-old man was admitted to an emergent hospital with hypovolemic pre-shock and open fracture of the right lower extremity. CPR was needed for myocardial infarction induced by hemorrhagic shock. Wound infection and bacteremia (Enterococcus SP) were noted 10 days after admission. Severe three vessel disease was demonstrated by preoperative (amputation) evaluation, he was also referred for CABG. For a control of infectious focus before using cardiopulmonary bypass, two-stage-operation (amputation and CABG) were selected. Both perioperative courses were uneventful and the patient recovered well after rehabilitation.

Amputation, Surgical↗
PubMed1998

[Intrapulmonary arterial injection of Albunex for left heart contrast echocardiography].

Contrast enhancement of the left heart cavity and myocardium were assessed after venous injection of the ultrasound contrast agent Albunex. Myocardial perfusion was also assessed using a drug stress and image analyzing system. The study population consisted of 46 patients with normal cardiac function and without coronary artery disease, and 38 patients with effort angina. Contrast echocardiography was performed by imaging the parasternal or apical long-axis view during pulmonary arterial injection of Albunex through a Swan-Ganz catheter. Contrast enhancement in the left ventricular cavity and ascending aorta were visually assessed. Hemodynamic, arterial blood gas and electrocardiography changes were recorded before and after the injection of Albunex. Contrast echocardiography was performed before and during intravenous infusion of dipyridamole to assess left ventricular myocardial enhancement by both visual inspection and peak background-subtracted gray level using an image analyzing system. Doppler flow signal change after the injection of Albunex was assessed in 26 patients using a Doppler guide wire located in the left anterior descending coronary artery. Good contrast enhancement was obtained in all patients in the left ventricular cavity and in 17% of patients in the ascending aorta. No significant changes were observed in hemodynamics, electrocardiograms and aortic gas analysis. Significant myocardial enhancement was not seen in any patient but gray level analysis of the echo images during dipyridamole infusion showed significant enhancement in 25% of the patients without coronary artery disease and in 34% of the patients with effort angina. Doppler flow signal in the coronary artery was significantly augmented in all patients after injection of Albunex and suggests that ultrasound contrast agent reaches coronary arteries in all patients regardless of myocardial contrast enhancement. Contrast echocardiography with pulmonary arterial injection of Albunex is safe and useful to obtain sufficient left ventricular contrast enhancement. For myocardial perfusion assessment, further refinement of the ultrasound contrast agent and echo equipment is necessary.

Adult↗
PubMed1998

[Mucosal microcirculation and angiogenesis in gastrointestinal tract].

In this review, various aspects of gastrointestinal microcirculation were described. Endothelin-1, vasoconstrictor, is elevated in gastric mucosa, causes gastric ischemia and results in gastric ulceration in human and animals under physical stress. Vasodilators such as NO anticipate the alove actions of endothelin, and thereby protect mucosa from injury. Once ulcer is developed, angiogenesis plays a key role in its healing. Various growth factors, cyclooxygenases-1 and -2, and non-peptide angiogenic factors stimulate this phenomenon and participate in ulcer healing. However, acidic conditions, H. pylori and its product, ammonia, suppress angiogenesis in vitro and in vivo. These evidences may explain why ulcer heals so slowly in gastroduodenal mucosa.

Animals↗
PubMed1998

Dual mechanisms of Mg2+ block of ryanodine receptor Ca2+ release channel from cardiac sarcoplasmic reticulum.

We investigated the effects of cytosolic Mg2+ on ryanodine receptor Ca2+ release channel (RyR) of bovine cardiac sarcoplasmic reticulum incorporated into planar lipid bilayers recording single channel activities. Channels were activated by > or = 0.1 microM Ca2+ in the cis solution. At constant Ca2+, application of Mg2+ (0.1-1 mM) to cis side decreased channel activity in a concentration-dependent manner. A half maximal blocking concentration (Kd) was 35 microM and a complete block was obtained at 1 mM. In the presence of 1 mM free Mg2+ in cis solution, the relation between the channel open probability (Po) and concentration of free Ca2+ in cis solution ([Ca2+]cis) shifted to the right, indicating the competition of Mg2+ and Ca2+. Blocking effects of Mg2+ on RyR were antagonized by increasing [Ca2+]cis > or = 0.1 mM. In the presence of 1 m Mg2+ and 1 mM Ca2+ in cis solution, the channel conductance was markedly depressed to approximately 400 pS (n = 7) from 603 +/- 40 pS (mean +/- S.D., n = 22) in the absence of Mg2+, indicating the flickering block. These results show that Mg2+ causes a direct inhibition of RyR in cardiac SR and this inhibition may be mediated through two different mechanisms. A competition of Mg2+ and Ca2+ at a Ca2+ sensitive site on the RyR and a flickery block of the open channel by Mg2+.

Animals↗