Biomedical subjects

Y Kamada

Publications and source records attributed to Y Kamada.

At least 55 records · Page 3Linked to original sources

PubMed1999

Distribution and localization of cells and collagens in the proliferated intima of arterially implanted autovein grafts.

We examined the microscopic features and distribution of collagens in the hyperplastic intima of arterially implanted autovein bypass grafts under conditions of a reduced blood flow with a poor distal outflow. Vascular anastomosis was made using 7-0 nonabsorbable polypropylene sutures (PP group), or absorbable polydioxanone sutures (PDS group). On the contralateral limb, an autovein bypass graft was performed under normal flow conditions (NF group). The thickness of the intima in the NF group was approximately 50 microm throughout the duration of the study, while in the PP and PDS groups, intimal hyperplasia progressed to 290+/-112 microm and 267+/-123 microm, respectively, at 13 months after grafting. Collagen accumulated significantly in both the PP and PDS groups; types IV and V collagen in particular increased considerably in the deep layer. Regardless of the suture materials, the progression of intimal hyperplasia was considered to be closely related to the poor distal outflow to be and caused by the proliferation of myofibroblasts and active production of collagen. The increase in types IV and V collagen, particularly in the deep layer of the hyperplastic intima, was due to development of numerous vasa vasora in this region.

Anastomosis, Surgical↗

PubMed1999

Increased sensitivity to stress and episode recurrence in spontaneous recurrence of methamphetamine psychosis.

Increased sensitivity to stress associated with noradrenergic hyperactivity and dopaminergic changes may precipitate stress-related psychiatric disorders. The present study examines the relation between this increased sensitivity and vulnerability to subsequent spontaneous recurrences of methamphetamine (MAP) psychosis (i.e. flashbacks). Plasma monoamine metabolite levels were assayed in 18 subjects with flashbacks, of whom ten experienced a single flashback and eight experienced further subsequent flashbacks; in 21 subjects with a history of MAP psychosis who did not experience flashbacks; and 33 controls. A square-root transformation was applied to monoaminergic values, rendering the distribution normal. The subjects with flashbacks had undergone frightening stressful experiences during previous MAP use. The dominant factor triggering flashbacks was a mild fear of other people. During flashbacks, plasma noradrenaline levels markedly increased and 3-methoxytyramine levels, an indicator of dopamine release, were elevated. Among the 18 subjects with flashbacks, the ten with subsequent flashbacks had markedly increased noradrenaline levels during flashbacks, whereas the eight with a single flashback displayed small increases in noradrenaline levels as well as 3-methoxytyramine levels. Thus, a mild fear of other people may have elicited memories of MAP psychosis, related to frightening stressful experiences through increased sensitivity to stress associated with noradrenergic hyperactivity, involving increased dopamine release. Robust noradrenergic hyperreactivity to mild stress may predispose subjects to subsequent flashbacks.

Adult↗

PubMed1999

Changes in respiratory pattern and arterial blood gases during sedation with propofol or midazolam in spinal anesthesia.

STUDY OBJECTIVE: To investigate changes in respiratory pattern and arterial blood gases during sedation with propofol or midazolam in spinal anesthesia. DESIGN: Randomized, placebo-controlled study. SETTING: Operating room of a university-affiliated hospital. PATIENTS: 40 ASA physical status I and II patients who required spinal anesthesia. INTERVENTIONS: Spinal anesthesia with tetracaine and subsequent sedation with propofol (n = 15), midazolam (n = 15), or placebo (n = 10) was performed. MEASUREMENTS: Respiratory pattern [rib cage contribution to the tidal volume (%RC) and phase shift between rib cage and abdominal movements (PSrc-ab)] with a respiratory inductive plethysmograph (Respigraph) and arterial blood gas analysis (pH, pO2, and pCO2) were recorded. MAIN RESULTS: Spinal anesthesia per se increased %RC by 35% without changing PSrc-ab values (1.00). Sedation with propofol and midazolam decreased %RC by 60% and by 40%, respectively. PSrc-ab increased in both groups following sedation, and the increase in this parameter was higher in the propofol group (1.12) than in the midazolam group (1.04). In the placebo group, %RC decreased by 20% without any change in PSrc-ab. The decrease in pO2 was more significant in the propofol group (65.1 mmHg) than in the midazolam (74.2 mmHg) and placebo (83.1 mmHg) groups. CONCLUSION: Significant decreases in %RC and pO2 during propofol sedation seem to depend on paradoxical respiration due, in part, to upper airway obstruction; therefore, attention should be directed to the respiratory pattern during sedation, especially with propofol.

Adult↗

PubMed1999

Chemoprevention by curcumin during the promotion stage of tumorigenesis of mammary gland in rats irradiated with gamma-rays.

We have evaluated the chemopreventive effects of curcumin on diethylstilbestrol (DES)-induced tumor promotion of rat mammary glands initiated with radiation. Sixty-four pregnant rats received whole body irradiation with 2.6 Gy gamma-rays from a 60Co source at day 20 of pregnancy and were divided into two groups after weaning. In the control group of 39 rats fed a basal diet and then implanted with a DES pellet for 1 year, 33 (84.6%) developed mammary tumors. Twenty-five rats were fed diet containing 1% curcumin immediately after weaning and received a DES pellet, as for the control. The administration of dietary curcumin significantly reduced the incidence (28.0%) of mammary tumors. Multiplicity and Iball's index of mammary tumors were also decreased by curcumin. Rats fed the curcumin diet showed a reduced incidence of the development of both mammary adenocarcinoma and ER(+)PgR(+) tumors in comparison with the control group. On long-term treatment with curcumin, body weight and ovarian weight were reduced, but liver weight was increased. Compared with the control rats, the curcumin-fed rats showed a significant reduction in serum prolactin, whereas estradiol-17beta and progesterone concentrations were not significantly different between the two groups. Curcumin did not have any effect on the concentration of free cholesterol, cholesterol ester and triglyceride. Feeding of the curcumin diet caused a significant increase in the concentrations of tetrahydrocurcumin, arachidonic acid and eicosapentaenoic acid and a significant decrease in thiobarbituric acid-reactive substance concentration in serum. Whole mounts of the mammary glands showed that curcumin yielded morphologically indistinguishable proliferation and differentiation from the glands of the control rats. These findings suggest that curcumin has a potent preventive activity during the DES-dependent promotion stage of radiation-induced mammary tumorigenesis.

Animals↗

PubMed1999

Generation of peroxynitrite and apoptosis in placenta of patients with chorioamnionitis: possible implications in placental abruption.

The reaction of nitric oxide (NO) and superoxide results in the formation of peroxynitrite, a potent and relatively long-lived oxidant. In infectious diseases, these molecules are not only bactericidal but also toxic to host cells. Chorioamnionitis is often complicated by premature rupture of membranes and can be associated with placental abruption. These diseases are significant causes of premature low-birth-weight deliveries and consequently the morbidity and mortality of neonates. Lipopolysaccharide, bacterial endotoxin, is known to be elevated in the amniotic fluid of patients with chorioamnionitis. Lipopolysaccharide is known to induce the formation of NO and superoxide. We report here that nitrite/nitrate, stable metabolites of NO, were increased in serum from patients with chorioamnionitis. Immunohistochemical studies demonstrated enhanced expression of inducible NO synthase and formation of nitrotyrosine, a footprint of peroxynitrite, in the placentae from patients with chorioamnionitis and also in patients with placental abruption. Furthermore, apoptotic cell death was also increased in the placentae from patients with both diseases. These results suggest that chorioamnionitis and a portion of placental abruption may share a common cascade of placental injury. Nitric oxide and its metabolities may play an important role in this cascade.

Adult↗

PubMed1999

Clinical experience of long-term transdermal treatment with nitric oxide donor for women with preeclampsia.

Isosorbide dinitrate (ISDN), a nitric oxide donor, was applied transdermally for 4-16 days to 4 preeclamptic women with oligohydramnios, intrauterine fetal growth retardation (IUGR), and elevated resistance of blood flow in the uterine arteries. Pulsed Doppler ultrasonography revealed immediate and drastic improvement of pulsatility index (PI) of uterine arteries following treatment with ISDN. The average PI in uterine arteries of the 4 patients was reduced to approximately 67% of that of the untreated state. In 2 patients the amniotic fluid gradually increased over a few days which suggested improvement of fetoplacental circulation during administration of ISDN. This study suggests that long-term transdermal ISDN is an effective therapy, at least in a portion of preeclamptic women, to avoid maternal hypertension, fetal distress, oligohydramnios, and IUGR, and consequentially to prolong the gestational period.

Administration, Cutaneous↗

PubMed1999

Whole-blood flow-cytometric analysis of induction of adhesion molecules expression on eosinophils stimulated by phorbol-12-myristate-13-acetate/ionomycin.

BACKGROUND: Activation of eosinophils is closely associated with the pathology of allergic inflammatory disease, especially bronchial asthma. We recently investigated the activation of eosinophils by applying whole blood to a flow cytometer. We measured here beta1 and beta2 integrin on eosinophils stimulated by phorbol-12-myristate-13-acetate (PMA)/ionomycin to evaluate eosinophil activation in vitro using whole blood. METHODS: Heparinized whole blood was diluted with the same volume of RPMI 1640, then cells were incubated in the presence or absence of PMA and ionomycin for 45 min at 37 degrees C. After hemolyzation with lysing solution, flow-cytometric findings for CR3, LFA1-alpha, LFA1-beta and VLA-4 expression on eosinophils were examined. RESULTS: Mean fluorescent intensity (MFI) of CR3 and LFA1-beta stimulated by PMA and ionomycin was significantly higher than that of the unstimulated control. MFI of LFA1-alpha showed no significant difference from the unstimulated control. On the other hand, MFI of VLA-4 tended to decrease. CONCLUSIONS: Our method to distinguish eosinophils from various cell groups in whole blood is simple and time-saving, similar to conditions in vivo and may allow intensive investigation of eosinophils in clinical laboratories as well as in research laboratories. We are currently investigating the influence of different kinds of stimulations, regulation factors or agents on eosinophils using this method.

Carcinogens↗

PubMed1999

CCR3 mRNA expression in bronchial epithelial cells and various cells in allergic inflammation.

BACKGROUND: RANTES and eotaxin are important chemokines involved in the activation and migration of eosinophils and are considered to play a major role in allergic inflammation. METHODS: In this study, we used RT-PCR to investigate the kinds of cells that express mRNA for CCR3, a common receptor of these chemokines, and eotaxin, a ligand for CCR3. RESULTS: CCR3 mRNA was expressed in eosinophils, peripheral mononuclear cells, an eosinophilic cell line (EoL-1), a bronchial epithelial cell line (NCI-H(292)), human endothelial cells and nasal washings from patients with allergic rhinitis. CONCLUSION: These results suggest that the CCR3-eotaxin system plays an important role in generating inflammation, since these substances are expressed not only in cells implicated in activation or migration of eosinophils but also in various other cells involved in allergic inflammation.

Bronchi↗

PubMed1999

Effect of eotaxin on the generationof reactive oxygen species from eosinophil cell line, YY-1.

BACKGROUND: The CC chemokine eotaxin is a selective chemoattractant for eosinophils. Eosinophils have been considered to be the major effector cells in allergic inflammation, since not only eosinophil-specific granule proteins but also reactive oxygen species (ROS) from eosinophils may cause the damage to the cells or tissue of the mucosal epithelium. In this study, we examined the effect of eotaxin on ROS from an eosinophil cell line, YY-1. METHODS: ROS in luminol-dependent reaction were examined. Calcium ionophore A23187 were added to the mixture of YY-1 cells with luminol, and then ROS were determined. RESULTS: Eotaxin primed the production of ROS from YY-1 cells. ROS from untreated YY-1 cells evoked with calcium ionophore A23187 in luminol-dependent chemiluminescence gave a maximal value of 1,928 +/- 223 intensity counts (IC; mean +/- SE, n = 4) and an integral value of 17.04 +/- 1. 51 IC (x10(-4)), while eosinophils that were treated with eotaxin gave a maximal value of 2,264 +/- 86 IC (10 nM), 2,691 +/- 124 IC (100 nM) and an integral value of 21.22 +/- 0.67 IC (x10(-4); 10 nM), 26.20 +/- 1.41 IC (x10(-4); 100 nM). CONCLUSION: Eotaxin might play important roles in the pathogenesis of allergic inflammation through eosinophil activation by priming of eosinophil oxidative metabolism as well as involvement in selective eosinophil chemotaxis.

Cell Line↗

PubMed1999

Coxsackievirus B4 myocarditis in an orangutan.

A 37-year-old female orangutan died at the zoological garden. Autopsy examination demonstrated severe coxsackievirus B4 myocarditis immunohistochemically as a cause of the death. Apoptosis of the cardiac muscle cells was observed using the TdT-mediated dUTP-biotin nick endo labeling method and was considered to play a role in the myocarditis. Congestion of the liver and both lungs due to cardiac failure was also observed. Coxsackievirus infection is found frequently in the Okinawan human population. The present orangutan's infection might have come from visitors who were allowed to go near the orangutan. Malignant tumors, severe suppurative infections, and intestinal parasite infections were not observed. Epstein-Barr virus DNA was detected in lymph nodes, but there was no Burkitt's lymphoma.

Animals↗

PubMed1999

A new devised skirted elephant trunk technique.

A simple and effective new elephant trunk technique was devised and applied to two patients with a successful result. In advance before the operation, an arch graft with a skirted elephant trunk was made. This was done by inserting a smaller, 22 mm diameter sized graft into the arch graft at the distal end and suturing it so as to leave a skirt extending over the smaller graft. This configuration facilitates the distal anastomosis and effectively shortens anastomotic time.

Adult↗

PubMed1999

[Effects of speed of injection on anesthesia induction with propofol and fentanyl].

We examined the effects of injection rate of propofol on injection pain and postinduction hypotension and bradycardia when fentanyl was administrated before propofol. Fifty-five patients premedicated with midazolam and atropine were randomly allocated to two groups. Three minutes after administration of fentanyl 100 micrograms, propofol 1.5 mg.kg-1 was injected to a forearm vein at a rate of 800 ml.hr-1 in Group FS or 1 ml.s-1 in Group FR. Anesthesia was maintained with 67% nitrous oxide in oxygen and supplemental propofol infusion. The incidence and severity of pain on injection were not influenced with injection speed. The rapid rate of injection significantly shortened the induction time. The decrease in systolic and diastolic blood pressures and heart rate after induction were not affected by injection speed. In conclusion, rapid injection of propofol after fentanyl was effective to shorten the induction time without increasing the postinduction hypotension and bradycardia.

Aged↗

PubMed1999

[Effects of the bolus injection rate on anesthesia induction with propofol].

We examined the influence of the bolus injection rate of propofol on the cardiovascular depression and injection pain. Fifty-one patients of ASA grade 1 or 2 were randomly allocated to two groups. After premedication with midazolam 0.06 mg.kg-1 and atropine 0.006 mg.kg-1 i.m., propofol 2 mg.kg-1 was injected to a forearm vein at a rate of 800 ml.hr-1 in Group A or 1 ml.s-1 in Group B. Anesthesia was maintained thereafter with 67% nitrous oxide in oxygen and propofol infused at 6 mg.kg-1.hr-1. The incidence and severity of pain on injection were lower in Group B compared with Group A, but the difference was not statistically significant. The induction time was significantly shorter in Group B than in Group A (40 vs. 73 sec: P < 0.01). There were no significant differences between the two injection rates in peak reductions in systolic and diastolic blood pressure and heart rate. In conclusion, rapid injection of propofol was effective to shorten the induction time without any adverse effects.

Adolescent↗

PubMed1999

[Is local anesthesia necessary for spinal needle insertion?].

It is a routine procedure for anesthesiologists to use local anesthesia (LA) before spinal needle insertion (SNI), but LA itself produces pain on injection. We evaluated the necessity of LA before spinal block using a 25-gauge needle by questioning whether LA makes SNI painless and easy. Sixty patients without lumbar abnormality for spinal block were allocated to 3 groups: Group A, LA with 2 ml of 1% lidocaine using a 24-gauge needle; Group B, LA with 0.5 ml of 1% lidocaine using a 27-gauge needle; Group C, without LA. Visual analog pain scales of LA and SNI were obtained respectively. Though LA reduced the pain associated with SNI, total pain scales in Group A and Group B were significantly larger than those in Group C. The pain scale of LA was significantly lower in Group B than Group A, but there were no significant differences in the pain on SNI between the Groups. The times needed for SNI were not significantly different among the three Groups. In conclusion, LA with 2 ml of 1% lidocaine using a 24-gauge needle is not useful for pain relief on spinal block using a 25-gauge needle. Intradermal anesthesia using a 27-gauge needle is preferable to reduce the pain on SNI, if LA is necessary.

Adult↗

PubMed1999

[Utility of an infrared ear thermometer as an intraoperative core temperature monitor].

We investigated the utility of an infrared ear thermometer (M 10, Terumo) as an intraoperative core temperature monitor. Temperatures of the axilla and inner ear were measured before and after anesthesia. Bladder, rectal, and forehead deep temperatures were continuously measured using a core temperature monitor (CTM-205, Terumo) during anesthesia. At the same time, the temperature of the inner ear was measured 4 times every 15 minutes (twice from cephalad and twice from caudal directions). There were no significant differences in the measured inner ear temperatures, either between directions of measurement or between the 1st and 2nd measurements. The inner ear temperature showed a close correlation with rectal, bladder, forehead deep, and axillary temperatures (r = 0.72-0.79, P < 0.01). The smallest temperature difference in this study was found to be that between the inner ear and forehead deep temperatures (-0.10), and the limit of agreement between these temperatures was also the smallest (0.81). In conclusion, we recommended the use of an infrared ear thermometer as an intraoperative core temperature monitor, especially in lower abdominal surgery, in which neither rectal nor bladder temperature monitoring is reliable.

Anesthesia, General↗

PubMed1998

Reconstitution of peptide bond formation with Escherichia coli 23S ribosomal RNA domains.

It was recently demonstrated that peptide bond formation can occur using an Escherichia coli naked 23S ribosomal RNA without any of the ribosomal proteins. Here, the six domains of the 23S ribosomal RNA were individually synthesized and shown to be capable, when complexed together, of stimulating the reaction. Omission and addition experiments indicated that the activity could be reconstituted solely by domain V at a concentration 10 times higher than that of the intact 23S ribosomal RNA, whereas domain VI could enhance the activity in trans. These findings suggest that fragments of an RNA molecule have the ability to associate into a functional whole.

Catalysis↗

PubMed1998

[Thoracoscopic surgery for diagnosis of interstitial pneumonia special reference to medicoeconomical effect].

We compared thoracoscopic surgery (TS) and open thoracotomy for the diagnosis of interstitial pneumonia. Intraoperative blood loss and duration of postoperative chest drainage were significantly less with TS than with thoracotomy. The length of postoperative hospital stay and social insurance costs with TS was significantly less than with thoracotomy. These results show that TS for the diagnosis of interstitial pneumonia is superior to open thoracotomy in terms of surgical stress and cost.

Adult↗

PubMed1998

Successful treatment of bilateral deep femoral aneurysms and multiple iliac aneurysms associated with severe aortic valve disease: report of a case.

We report herein the case of a patient in whom aneurysms of the bilateral deep femoral arteries (DFA) and multiple iliac aneurysms associated with severe aortic valve disease were successfully treated by a two-staged operation. The patient was a 74-year-old man who had dense calcification of the ascending aorta and aortic arch. Prior to aortic valve replacement (AVR), the aneurysms of the DFA and internal iliac arteries were resected. The terminal end of the abdominal aorta and bilateral common iliac arteries were then reconstructed with a Y graft to be used as a possible alternative arterial input route in place of the ascending aorta for extracorporeal circulation during the AVR. The inferior mesenteric artery (IMA) was well developed, and the external iliac arteries and their branches were preserved at aneurysmectomy. Postoperatively, there was no ischemia of the pelvic organs or the hip muscles. The AVR was subsequently performed 5 weeks after the first operation, and the patient was discharged after an uneventful postoperative course.

Aged↗