Biomedical subjects
R Saito
Publications and source records attributed to R Saito.
[The role of tachykinin NK-1 receptors in emetic action in the area postrema of ferrets].
Substance P (SP) is a member of the tachykinin family of bioactive peptides and has highest affinity for the NK-1 receptor. We have developed the non-peptide compound HSP-117 as a selective antagonist of the NK-1 receptor. Binding of 3H-SP to the membranes of IM-9 cells was inhibited by the antagonists HSP-117 and CP-99,994, the inhibitory activity of HSP-117 being 50-fold that of CP-99,994. The SP-induced firing responses of single neuron activity in slices of the nucleus tractus solitarius of ferrets were inhibited by 10 microM HSP-117. Intracerebroventricular injection of HSP-117 significantly inhibited retching and vomiting induced by copper sulphate and morphine and the inhibitory effect of HSP-117 on emesis was greater than that of CP-99,994. Moreover, emesis induced by copper sulphate and morphine were inhibited by the microinjection of HSP-117 and CP-99,994 into the area postrema and by lesion of the area postrema. These results indicate that HSP-117 is a potent anti-emetic agent, blocking NK-1 receptors in the area postrema and that NK-1 receptors in the area postrema play an important role in emesis induced by broad-spectrum emetic stimuli.
Biphasic relaxation caused by electrical field stimulation of the mesenteric arteries of rats.
Electrical field stimulation (EFS) caused biphasic relaxation, first transient and then sustained, of rat mesenteric arteries precontracted by prostaglandin (PG) F2alpha. The transient relaxation was reduced about 45%, and the sustained relaxation was not observed after endothelium denudation of the arteries. N(omega)-Nitro-L-arginine (L-NOARG) inhibited the biphasic relaxation induced by EFS. At 1 - 100 microM, L-NOARG inhibited the transient relaxation more than the sustained relaxation. Methylene blue inhibited the biphasic relaxation and at 100 microM, L-NOARG abolished the transient relaxation. These results suggest that the transient relaxation mainly involves nitric oxide (NO), whereas the sustained relaxation involves both NO and some other factor(s).
Endogenous ATP released by electrical field stimulation causes contraction via P2x- and P2y-purinoceptors in the isolated tail artery of rats.
Electrical field stimulation (EFS) caused contraction of isolated tail arteries of rats. The EFS-induced contraction showed frequency-dependence and was entirely abolished by the sodium channel blocker tetrodotoxin (1 x 10(-7) M). The EFS-induced (at 20 Hz) contraction was reduced by about 60% in the presence of phentolamine (1 x 10(-6) M). Therefore, later experiments were carried out in the presence of phentolamine. Pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) (1 x 10(-8)-1 x 10(-6) M) and basilen blue E-3G (3 x 10(-5)-5 x 10(-5) M), P2-receptor antagonists, significantly inhibited the contraction evoked by EFS. In addition, PPADS significantly inhibited the contractions induced by ATP (1 x 10(-4) M) and a selective P2x-receptor agonist, alpha,beta-methylene ATP (1 x 10(-6) M). In contrast, basilen blue E-3G did not inhibit alpha,beta-methylene ATP-induced contraction. The ecto-ATPase activator apyrase (5 and 10 U/ml) significantly reduced the EFS-induced contractions. These findings suggest that endogenous ATP released by EFS causes contractions of rat tail artery via both the P2x-receptors and P2y-receptors.
Ruptured vertebral artery-posterior inferior cerebellar artery aneurysm associated with facial nerve paresis successfully treated with interlocking detachable coils--case report.
An 81-year-old female presented with severe headache. Computed tomography revealed subarachnoid hemorrhage. She developed right facial nerve paresis on the next day. Angiography revealed a right vertebral artery-posterior inferior cerebellar artery aneurysm. The aneurysm was successfully occluded with interlocking detachable coils (IDCs) on the 7th day. Magnetic resonance (MR) imaging 1 month after IDC placement showed partially thrombosed aneurysm near the internal acoustic meatus. Ten months after the ictus, MR imaging revealed marked resolution of the intra-aneurysmal thrombus and reduction of the aneurysm size. Her facial nerve function gradually recovered during this period. Her facial nerve paresis was probably caused by acute stretching of the facial nerve by the ruptured aneurysm that was in direct contact with the nerve. Intra-aneurysmal thrombosis using coils can reduce aneurysm size and alleviate cranial nerve symptoms.
Prognostic significance of allelic imbalances on chromosome 9p in stage I non-small cell lung carcinoma.
Loss of heterozygosity (LOH) on chromosomes 2q, 9p, 18q, and 22q frequently occurs in advanced non-small cell lung carcinoma (NSCLC). The association of p53 mutations with prognosis is still unclear in NSCLC. Therefore, we investigated the prognostic significance of allelic imbalances (AI) on these chromosomes and p53 mutations in 108 cases of stage I NSCLC by PCR amplification of polymorphic dinucleotide repeat-containing sequences and PCR-single strand conformation polymorphism analysis. AI on 2q, 9p, 18q, and 22q was detected in 22, 38, 29, and 15% of cases, respectively, whereas p53 was mutated in 41% of stage I NSCLC. AI on 9p and 22q and p53 mutations were significantly associated with shortened survival of the patients (P = 0.010, 0.024, and 0.022, respectively). Although gender and smoking history showed more significant associations with prognosis than other clinicopathological and molecular parameters, independent prognostic significance for AI on 9p was observed (P = 0.002) in male patients with a positive smoking history. These results indicate that clinical aggressiveness of early-stage NSCLC can be partly defined by the presence of AI on chromosome 9p in cancer cells, and that AI on 9p could be a clinically useful prognostic indicator for early-stage NSCLC patients.
[Analysis of actual coverage of the immunization program in Niigata Prefecture and development of a simple estimation of its coverage].
OBJECTIVE: We investigated measles immunization coverage and the actual situation of immunization in Niigata Pref. METHOD: We distributed questionnaires to all parents of pediatric outpatients who went to hospitals and clinics in Niigata Pref. from January 20 to 31. In the questionnaire, we asked parents about the measles immunization status of not only patients but also their sisters and brothers in each household, reasons for their immunization failure, and sources of information on immunization. We were able to collect 4,840 questionnaires from the parents who lived in Niigata Pref. and analyzable data obtained from 9,783 children. Furthermore we compared these with data from official annual reports of public health centers in Niigata Pref. RESULT: Our survey showed that around 90% of the children who had been born since 1979 to 1993 had received measles vaccine, while the official annual reports indicated low immunization coverage (around 70%). The age at which children received measles vaccine was one year old (38.2% of the vaccinated) and two years old (37.5%), and finally 93.6% of children were immunized by three years old. The primary reason for failure to receive immunization was that he or she was infected with measles before immunization (30.4%). Around 53% of these were infected with measles by 2 years old. With regard to sources of information on immunization, public announcements and letters were the greatest sources, whereas the contribution of doctors and paramedical staffs which was expected to be the main providers of the information to parents was quite low. CONCLUSIONS: 1) It was shown that there was a difference of measles immunization coverage between our results (90%) and the official record (70%), indicating that the current coverage survey method does not reflect the actual situation of immunization. Since more than 90% of children were immunized by three years old, we recommend that measles immunization coverage should be surveyed through interviews and data in maternity record book at the health examination for three year-old children which is operated by the government and has good attendance. 2) More than 50% of children who were infected with measles before immunization were infected by two years old, suggesting further promotion of measles immunization before two years old. 3) The main source of information on immunization was public announcements and publications. Further participation of doctors and paramedical staffs in disseminating information and providing education activities is desired.
Clinicopathological significance of Fhit protein expression in stage I non-small cell lung carcinoma.
Abnormalities in structure and expression of the FHIT gene have been detected in a considerable fraction of primary lung tumors. Previous reports indicated that FHIT gene alterations can be simply detected by immunohistochemical methods. Therefore, we investigated the association of Fhit expression with clinicopathological features and allelic imbalance (AI) at the FHIT locus in 105 stage I non-small cell lung cancers (NSCLC) by the immunohistological method and PCR analysis. Thirty-six of 105 (34%) tumors showed marked reduction of Fhit immunoreactivity. Fhit expression was markedly reduced in most squamous cell carcinomas (24 of 28, 86%), whereas such a reduction was detected only in a small subset of adenocarcinomas (7 of 67, 10%; P < 0.001). A marked reduction of Fhit protein expression was observed more frequently in patients with a smoking history (32 of 80, 40%) than in patients without a smoking history (4 of 25, 16%; P = 0.013). These results indicate that FHIT gene alterations preferentially occur in squamous cell carcinomas and in smokers. Furthermore, a reduction of Fhit protein expression in tumor cells was associated with a poorer survival of patients with stage I NSCLC, irrespective of histological subtypes of tumors (P = 0.005; log-rank test). Fhit expression was reduced preferentially in tumors with AI at the FHIT locus; however, AI at the FHIT locus did not correlate with patients' survival (P = 0.262; log-rank test). These results suggested that Fhit protein expression could be a useful molecular marker for the prognosis of patients with surgically resected stage I NSCLC.
Effects of arginine-vasopressin on neuronal interaction from the area postrema to the nucleus tractus solitarii in rat brain slices.
The effects of arginine-vasopressin (AVP) on area postrema (AP) neurons and the neuronal connection between the AP and nucleus tractus solitarii (NTS) were electrophysiologically investigated in rat medulla slices. In the AP, 27.9% of 129 neurons were excited by AVP and 20.5% were inhibited. The excitation was blocked by an V1 receptor antagonist. Synaptic transmission of the AP to the NTS was mainly mediated by non-N-methyl-D-aspartate (NMDA) receptors. Local application of AVP to the AP activated the NTS neurons. This excitation was also blocked by an NMDA antagonist. These results suggest that the excitation originating in the AP is conveyed to the NTS via non-NMDA receptors and then modified by NMDA receptor activation secondly. These processes may be important in the regulation of the arterial baroreceptor reflex.
Anti-emetic effects of a novel NK-1 receptor antagonist HSP-117 in ferrets.
We have developed a non-peptide compound, HSP-117, antagonist of the tachykinin NK-1 receptor. Binding of 3H-substance P (SP) to the membranes of IM-9 cells was inhibited by the antagonists HSP-117 and CP-99,994, the inhibitory activity of HSP-117 being about 50-fold that of CP-99,994. The SP-induced firing responses of single neuron activity in slices of the nucleus tractus solitarius of ferrets were inhibited by 10 microM HSP-117. Intracerebroventricular injection of HSP-117 significantly inhibited retching and vomiting induced by copper sulphate and morphine and the inhibitory effect of HSP-117 on emesis was greater than that of CP-99,994. These results indicate that (1) HSP-117 is a potent anti-emetic agent, blocking NK-1 receptors in the nucleus tractus solitarius and (2) NK-1 receptors in the nucleus tractus solitarius play an important role in emesis induced by broad-spectrum emetic stimuli.
Bcl-2 is located predominantly in the inner membrane and crista of mitochondria in rat liver.
Bcl-2 is now recognized as a potent inhibitor of apoptotic cell death. It has been reported that Bcl-2 is located in the mitochondria, endoplasmic reticulum, and nuclear membrane in some cell lines, and it is not expressed in normal human and rat liver. An earlier study showed that Bcl-2 is an inner mitochondrial membrane protein. On the contrary, the following investigations using immunoelectron microscopy demonstrated that Bcl-2 resides predominantly in the mitochondrial outer membrane. In this study, using a cryo-sectioning immunogold labeling technique and immunoblotting, we carefully determined the subcellular localization of Bcl-2. Here we report that Bcl-2 is expressed in normal rat liver, and it is located predominantly in the inner membrane and crista rather than in the outer membrane of mitochondria.
Central administration of a nitric oxide synthase inhibitor causes pressor responses via the sympathetic nervous system and the renin-angiotensin system in Wistar rats.
The central roles of nitric oxide (NO) in regulations of the blood pressure and heart rate were examined in anesthetized rats. Intracerebroventricular (i.c.v.) injection of Nomega-nitro-L-arginine methyl ester (L-NAME) caused dose-dependent increase in the blood pressure and heart rate. The pressor response of the blood pressure to L-NAME (2 micromol, i.c.v.) was reduced by L-arginine (5 micromol, i.c.v). Pretreatment with a ganglionic blocker, pentolinium (10 mg/kg, i.v.), significantly inhibited both pressor responses induced by L-NAME (2 micromol, i.c.v). The later pressor response of the blood pressure to L-NAME was also inhibited by the angiotensin II AT-1 blocker losartan (10 mg/kg, i.v). These results suggest that the response of the blood pressure to L-NAME is mediated by both the sympathetic nervous system and the renin-angiotensin system.
Peripheral edema after esophagectomy.
Patients who have undergone major surgery such as esophagectomy may develop peripheral edema in the immediate postoperative period, the cause of which is not fully understood. The purpose of this study was therefore to determine the mechanism of this phenomenon. Finger edema was measured as a marker for peripheral edema before and after esophagectomy in eight patients. Plasma interleukin-6 (IL-6) was also measured by an enzyme-linked immunosorbent assay. Finger edema markedly increased in the immediate postoperative period and remained significantly elevated until after postoperative day (POD) 3 compared to the preoperative value (P < 0.05). Plasma IL-6 also markedly increased in the immediate postoperative period and remained significantly elevated on POD 2 compared to the preoperative value (P < 0.05). The degree of finger edema highly correlated with the level of plasma IL-6 (r = 0.71, P = 0.0001). These findings indicate that peripheral edema after esophagectomy might be caused by a proinflammatory cytokine response.
[An analysis of the mechanism of postoperative hyperbilirubinemia following resection of thoracic esophageal cancer in terms of hepatic venous oxygen saturation and excessive systemic reactions].
Hepatic venous oxygen saturation (ShvO2), parameters of systemic circulation and cytokine (Interleukin 6) (IL-6)) level were measured in 21 patients with thoracic esophageal cancer in order to analyze the mechanism of occurrence of postoperative hyperbilirubinemia (PHB). ShvO2 fell during operation, especially during intrathoracic procedures, and a significant correlation was noted between the total time during which ShvO2 was below 60% and the postoperative peak serum bilirubin level (peak-Bil) (r = 0.595, p = 0.0037). Patients with PHB (group H) had worse systemic circulation and a lower oxygen supply postoperatively than patients without PHB (group N). Body weight and water balance recovered earlier in group N. Postoperatively, numbers of peripheral lymphocytes and platelets changed lower in group H, while CRP and IL-6 changed higher in group H. Furthermore, a significant correlation was noted between the IL-6 level just after operation and peak-Bil (r = 0.669, p = 0.0006). These results suggests PHB results from intraoperative liver hypoxia and poor postoperative systemic circulation. Individual severeness of reactions to the operative stress, excessive or adequate, plays a role in the occurrence of PHB as well.
Hydrogen peroxide derived from hepatocytes induces sinusoidal endothelial cell apoptosis in perfused hypoxic rat liver.
BACKGROUND & AIMS: Evidence is accumulating that hypoxic liver injury involves not only necrosis but also apoptosis. Reactive oxygen species can cause apoptosis. This study examined the hypothesis that H2O2 induces apoptosis in hypoxic rat liver. METHODS: Blood-perfused rat livers were made hypoxic by reducing the perfusion flow. H2O2 was detected by both 2',7'-dichlorofluorescein fluoroimaging and cerium electron-microscopic methods. To evaluate the apoptosis, the liver was stained with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) method. To further investigate the involvement of H2O2 in hypoxia-induced liver cell apoptosis, small pieces of liver in the cultured media were exposed to 0.5 mmol/L of reagent H2O2 and stained with the TUNEL method. RESULTS: In the hypoxic liver, H2O2 was produced predominantly by hepatocytes, and the number of apoptotic nonparenchymal cells was significantly increased, particularly in the midzone. All the apoptotic cells were positively stained with monoclonal antibody against the hepatic sinusoidal endothelial cells (SECs). In incubated liver pieces, reagent H2O2 induced apoptosis selectively in SECs. CONCLUSIONS: Low-flow hypoxia induces H2O2 production in hepatocytes, and this H2O2 induces apoptosis selectively in SECs in the rat liver.
Combined anterior thigh flaps and vascularised fibular graft for reconstruction of massive composite oromandibular defects.
Six massive, composite oromandibular defects were reconstructed using combined anterior (anterolateral and anteromedial) thigh flaps and vascularised fibular graft in bridge or chimeric fashion. Except for minor dehiscence in one case and infection in another, all flaps survived without complication. Anterior thigh flaps provide large-calibre, long vascular pedicles while derivative branches from the lateral circumflex femoral system facilitate simultaneous transplantation of multiple components. Because the pedicle of the vascularised fibular graft is of insufficient length, the lateral circumflex femoral vessels provide a remote vascular source as a flow-through vascular conduit. A combined flap using the lateral circumflex femoral system is considered to be most suitable for reconstruction of through-and-through defects of the head and neck. The authors describe the advantages of this method and the detailed anatomy of the cutaneous perforators of the anterior thigh flaps.
Identification and characterization of families with aggregation of lung cancer.
BACKGROUND: To clarify genetic factors involved in the susceptibility to lung cancer, it is essential to identify families with lung cancer clustering and to characterize the mode of clustering. Since somatic mutations of the p53, RB and p16 genes occur frequently in lung cancer and the replication error phenotype is seen in a subset of lung cancer, it is possible that germ-line mutations of the p53, RB, p16 and mismatch repair genes influence the susceptibility to lung cancer. METHODS: In this work, cases with familial clustering of lung cancer were selected from 1068 families with primary lung cancer cases in analogy with the criteria for hereditary non-polyposis colorectal cancer (HNPCC). Cases with Li-Fraumeni syndrome, familial retinoblastoma, familial melanoma and HNPCC were also searched among these 1068 families. RESULTS: There were only four families (0.4%) in which more than three relatives were affected by lung cancer. Two successive generations were affected in 36 families (3.4%). Patients with lung cancer before the age of 50 were present in 165 families (15.5%). However, no family conformed to all three criteria. There was only one family with Li-Fraumeni syndrome and no family with familial retinoblastoma, familial melanoma and HNPCC. CONCLUSION: Familial aggregation of lung cancer is rare and germ-line mutations of the p53, RB, p16 and mismatch repair genes may not contribute greatly to susceptibility to lung cancer.
Relationship between the structure and cytotoxic activity of asterriquinone, an antitumor metabolite of Aspergillus terreus, and its alkyl ether derivatives.
Asterriquinone (ARQ) is an antitumor metabolite of Aspergillus terreus IFO 6123. In this study we synthesized several ARQ alkyl ethers and studied their cytotoxic activity against mouse leukemia P388 cells. The dissociation constant was also similar among the ARQ monoalkyl ethers. There was a good correlation between the hydrophobicity of ARQ monoalkyl ethers estimated by high performance liquid chromatography and the intracellular content accumulated for 60 min. ARQ monoalkyl ethers were cytotoxic, but ARQ dimethyl ether was not, as previously reported. The cytotoxicity of the ARQ monoalkyl ether derivatives was increased with extension of the alkyl chain length. The cytotoxicity was closely correlated with the intracellular content. The strongest ARQ derivative, ARQ monohexyl ether (ARQHex), formed more DNA-interstrand cross-links in the cells than ARQ. After treatment of P388 cells with ARQ and ARQHex for 6 h, a nucleosomal ladder pattern, as well as the appearance of degraded DNA, observed by flow cytometry, indicated that these compounds caused cellular apoptosis. Moreover, ARQ and ARQHex accumulated in the cells at the G1 phase of the cell cycle. These results indicated that ARQ monoalkyl ethers increased cytotoxicity, according to their membrane permeability based on the hydrophobicity, and they caused apoptotic cell death, as did ARQ.