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Biomedical subjects

N Honda

Publications and source records attributed to N Honda.

At least 91 records · Page 5Linked to original sources
PubMed1995

The effects of imipramine, amitriptyline and clonidine administered by iontophoresis on the pain threshold.

We performed iontophoresis of aqueous solution of imipramine and amitriptyline, tricyclic antidepressant, and clonidine, an alpha 2 agonist, in a total of 30 healthy adult volunteers. Analgesic effects were compared among the 3 drugs by measurement of the pain threshold using a thermopainmeter. No significant changes in the pain threshold were observed with imipramine or amitriptyline. On the other hand, clonidine significantly increased the pain threshold, compared with the control value before iontophoresis. Although the effects of iontophoresis of clonidine were smaller than the previously reported effects of iontophoresis with other drugs, these effects seemed to be due to the action of clonidine itself not associated with electric stimulation. More marked effects may be obtained with changes in the conditions of iontophoresis.

Adrenergic alpha-Agonists↗
PubMed1995

The effect of calcium channel antagonist administered by iontophoresis on the pain threshold.

Three calcium (Ca) channel antagonists were administered to healthy adult volunteers by iontophoresis alone or in combination with lidocaine to study their effects on the pain threshold. Nicardipine, verapamil or diltiazem administered alone elevated the pain threshold to the same degree as lidocaine. When Ca channel antagonists were administered in combination with lidocaine, the pain threshold elevation was not changed, but the duration of the analgesic action was prolonged when compared with lidocaine alone. These results suggest a role of the calcium channel in the pain control mechanism and the possible clinical application of Ca channel antagonists delivered by iontophoresis in pain management.

Adult↗
PubMed1994

[Measurement of cerebral blood flow in normal subjects by phase contrast MR imaging].

Global cerebral blood flow (CBF) was quantitatively measured with a two-dimensional phase contrast cine magnetic resonance (MR) imaging technique in 24 normal subjects (mean age, 38.6 years; range, 12-70 years). Cine transverse images of the upper cervical region (32 phases/cardiac cycle) were acquired with a 1.5 Tesla MR imaging unit. In five subjects, measurement of CBF was performed before and after intravenous administration of acetazolamide (DIAMOX, 15 mg/kg). Inter- and intraobserver variations in flow volume measurement were small (r = 0.970, standard error of the estimate (SEE) = 2.9 ml/min, n = 80; r = 0.963, SEE = 4.6 ml/min, n = 40, respectively). In measuring flow velocity, they were inferior to those of flow volume measurement. On a visually determined setting of region of interest (ROI), reproducibly of the measurement of flow velocity was not satisfactory in this study. Thus only the results of flow volume measurement are presented. Mean summed vertebral flow volume (171 ml/min, SD = 40.6) was significantly less than mean summed internal carotid flow volume (523 ml/min, SD = 111). Total blood flow volume showed a significant decline with age (r = 0.45, p < 0.05). The mean proportions of carotid and vertebral flow volume to total flow volume were 75.3% and 24.7%, respectively, and showed no significant change with age. The left-to-right ratio of vertebral flow volume (1.39) was significantly higher than that of internal carotid flow volume (0.99, r = 0.05). After DIAMOX i.v., the mean rate of increase in total flow volume was 157%. Mean rates of increase in carotid and vertebral flow volume were 154% and 166%, respectively, which were not significantly different. In conclusion, this method is useful for estimating carotid and vertebral flow volume.

Acetazolamide↗
PubMed1994

Impaired hepatic function in segmental biliary obstruction demonstrated with a receptor-binding radiotracer.

A patient with cholangiocarcinoma underwent left-sided cholangiojejunostomy, and hepatic functional imaging with a receptor-binding radiotracer and SPECT was performed to evaluate the distribution of functional reserve. It revealed decreased accumulation in the regions with residual dilatation of the intrahepatic bile ducts, indicating several kinds of focal damage in hepatic function caused by segmental biliary obstruction. The radioligand may be useful in assessing regional hepatic function, and the high spatial resolution provided by SPECT appears to play an important role for this purpose.

Aged↗
PubMed1994

Glycine 85 of the trp-repressor of E. coli is important in forming the hydrophobic tryptophan binding pocket: experimental and computational approaches.

Experimental and computational analyses were performed on the corepressor (L-tryptophan) binding site of the trp-repressor of Escherichia coli to investigate the ligand-protein interactions. Gly85, one of the residues forming the hydrophobic pocket of the binding site, was systematically replaced with Ala, Val, Leu and Trp by cassette mutagenesis. Biochemical characterization showed that all these mutations caused significant decreases in tryptophan binding activity. Free energy perturbation calculations were performed for the mutants and were consistent with the experimental results. The lack of a side chain at position 85 was concluded to be essential for binding the corepressor; the structure of the binding pocket was suggested to be tight in the vicinity of Gly85.

Amino Acid Sequence↗
PubMed1994

Abnormal sympathetic innervation of the heart in a patient with myotonic dystrophy detected with I-123 MIBG cardiac SPECT.

Iodine-123 MIBG is a norepinephrine analog which can be used to image the sympathetic innervation of the heart. The authors report a patient with myotonic dystrophy whose I-123 MIBG SPECT revealed accelerated washout of I-123 MIBG from infero-posterior and a part of lateral wall, although Tl-201 SPECT showed no abnormal finding. The authors conclude that I-123 MIBG can be more sensitive in detecting the cardiac abnormality than Tl-201 SPECT in this disease.

3-Iodobenzylguanidine↗
PubMed1994

Background correction in estimating initial renal uptake. Comparison between Tc-99m MAG3 and Tc-99m DTPA.

A gamma camera method with no blood sampling assesses differential renal function based on initial renal uptake, and requires background correction. The effect of background correction on estimates of initial renal uptake was compared on renograms using Tc-99m MAG3 and Tc-99m DTPA renographies in 14 patients. Renal counts for 2-3 minutes were obtained using three sets of regions of interest (ROIs): rectangular renal and subrenal background ROIs, rectangular renal and perirenal background ROIs, and hand-drawn renal and subrenal background ROIs. Correlations between estimates of initial renal uptake by the three methods were higher for Tc-99m MAG3 renography than for Tc-99m DTPA imaging, suggesting higher reproducibility in evaluating differential renal function using Tc-99m MAG3 renography and a gamma camera method. Although the ratio of counts in the suprarenal area to those in the subrenal area was significantly higher for the right side in the Tc-99m MAG3 study, probably because of hepatic activity, the relative uptake in the right kidney for Tc-99m MAG3 did not differ from that for Tc-99m DTPA. Initial uptake of Tc-99m MAG3 was well correlated with, and about threefold that, of Tc-99m DTPA. It was suggested that initial renal uptake of Tc-99m MAG3 may be an alternative to that of Tc-99m DTPA, with less dependence on background correction in evaluating differential renal function.

Gamma Cameras↗
PubMed1994

Percutaneous hot saline injection therapy for hepatic tumors: an alternative to percutaneous ethanol injection therapy.

PURPOSE: To evaluate the usefulness of percutaneous hot saline injection therapy (PSIT) in the treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Twenty patients with HCC (23 nodules) underwent PSIT. Mean tumor diameter was < or = 30 mm. PSIT was performed by injecting hot saline into the HCC. The therapeutic effect of PSIT was evaluated with computed tomography, angiography, measurement of alpha-fetoprotein levels, and histopathologic examination of needle biopsy and resected specimens. RESULTS: No complications were encountered, and a therapeutic effect was obtained in all cases. When the injected material cools, it becomes physiologic saline making it possible to inject relatively large volumes in a single session. CONCLUSION: PSIT has promise as a form of curative local therapy for small HCCs and is expected to exert a safe and favorable therapeutic effect on large HCCs as well.

Aged↗
PubMed1994

Roles of hemodynamic and tubular factors in gentamicin-mediated nephropathy.

Gentamicin (GM) often causes polyuric acute renal failure (ARF) in humans and animals. GM-mediated ARF in rats was accompanied with activated renin-angiotensin system, increased renal endothelin content, and enhanced lipid peroxidation. Suppression of the renin-angiotensin activity by desoxycorticosterone acetate and saline drinking, and treatment with superoxide dismutase attenuated the GM-induced decline in whole-kidney GFR with well-maintained RBF but did not reduce the severity of tubular necrosis. On the other hand, treatment with dimethylthiourea, a hydroxyl radical scavenger, attenuated the GM-mediated decline in GFR and lessened tubular necrosis but did not ameliorate the reduction in RBF. These data suggest contributions of both vascular and tubular factors to the GM-induced decline in GFR in rats. However, relative importance of these factors probably differs with different doses of the agent.

Acute Kidney Injury↗
PubMed1994

Erythropoietin production in patients with chronic renal failure.

Studies were performed to reexamine the response of erythropoietin (Epo) production to acute hypoxic stimuli in patients with end-stage renal disease (ESRD). In the absence of acute bleeding or hypoxia, the serum Epo level in ESRD was similar to that of normal subjects despite severe anemia. In 11 dialysis patients with acute bleeding, the decrease in the Hb level from 8.9 to 5.8 g/dL provoked a significant increase in serum Epo up to 52.2 times the normal value. The increase in serum Epo was associated with a significant increase in corrected reticulocyte. Systemic hypoxemia (PaO2 < 65 mm Hg) in 8 dialysis patients provoked a significant elevation in the serum Epo level up to 24.6 times the normal level. There was an inverse relationship between serum Epo and arterial PaO2 (r = -0.715). The serum Epo level in these patients declined to or near the normal value after recovery from acute hypoxic stress. These data suggest that the ability of the Epo production is well preserved in ESRD, indicating that acute hypoxic stimuli provoke a significant increase in serum Epo.

Acute Disease↗
PubMed1994

Correlation between histologic features and glomerular permeability in membranous nephropathy and immunoglobulin A nephropathy.

We evaluated the correlation between histologic features and glomerular permselectivity based on fractional clearances of dextrans relative to inulin (FCsDex). The subjects consisted of 12 healthy volunteers, 18 patients with membranous nephropathy, and 20 patients with immunoglobulin A nephropathy. In membranous nephropathy, FCsDex measured with large dextrans (radii larger than 56 A) increased as the capillary lesion progressed. Histologic examination showed that glomerular capillary alteration was the factor most closely linked to changes in FCsDex in membranous nephropathy. Proteinuria (normalized to glomerular filtration rate) did not correlate with FCsDex. Increased FCsDex tended to normalize during prednisolone treatment in membranous nephropathy. In immunoglobulin A nephropathy, the impairment of glomerular size selectivity depended on the degree of mesangial sclerosis and tubulointerstitial injury. FCs of dextrans of 59 A were correlated with the mesangial sclerosis index (r = 0.573, p = 0.050) and the tubulointerstitial injury index (r = 0.707, p = 0.003). Proteinuria (again normalized to glomerular filtration rate) was significantly correlated with FCs of large dextrans in immunoglobulin A nephropathy (r = 0.668, p = 0.008). We conclude that glomerular size-selective barriers were impaired both in membranous nephropathy and immunoglobulin A nephropathy. However, the mechanisms of impaired size selectivity might differ, at least in part, between these nephropathies. The predominant factors responsible for the size-selective defect seemed to be glomerular capillary wall lesions in membranous nephropathy but mesangial sclerosis or tubulointerstitial damages (or both) in immunoglobulin A nephropathy.

Adolescent↗
PubMed1994

[Intra-ocular pressure changes during laparoscopic cholecystectomy].

Intra-ocular pressure (IOP) was measured during laparoscopic cholecystectomy (n = 20) under continuous epidural block and nitrous oxide-oxygen anesthesia. There was a slight but significant increase in IOP and peak airway pressure when the abdominal CO2 insuffration was started, and the IOP recovered to the preoperative level after the postural change to the head-up position. It was not associated with any significant change in mean arterial pressure and end-tidal CO2. In one ocular hypertension case undergoing laparoscopic chorecystectomy and appendectomy, however, there was profound increase in IOP during abdominal CO2 insuffration with head down position. We speculate that it was due to the effect of increased CVP with abdominal CO2 insuffration and postural change on the IOP. Thus the laparoscopic operation with head-down position should be avoided in patients with ocular hypertension.

Anesthesia, Epidural↗
PubMed1994

[Effect of pirenzepine on gastric mucosal blood flow in patients after cardiac surgery].

Effect of pirenzepine on gastric mucosal blood flow (GMBF) in adult patients after coronary artery bypass grafting and mitral and aortic valve replacement was evaluated by using endoscopic laser-Doppler velocimetry. Heart rate, blood pressure and cardiac output increased temporarily after intravenous administration of pirenzepine 20 mg. GMBF also increased with these hemodynamic changes. However, GMBF remained significantly higher even after the decrease of cardiac output. Therefore, the increase in GMBF, which might be due in part to increase in cardiac output, could be explained by pirenzepine's own effect on gastric mucosa. Since the GMBF is one of the most important gastric mucosal defensive factors, pirenzepine may be useful in preventing acute gastric mucosal lesions in patients with low cardiac output.

Aged↗
PubMed1994

[Evaluation of a new nitric oxide delivery system during mechanical ventilation].

A new nitric oxide delivery and continuous monitoring system is described. During mechanical ventilation, this new system connected with Siemens Servo 900C ventilator was shown to be able to provide a constant inspired NO concentration (10-100 ppm) using chemiluminescence technique for NO analysis. Gas was analysed at the mixing chamber in front of the ventilator inlet and inspiratory tube connected with the soda-lime carbon-dioxide absorber. Both NO concentrations showed a good correlation (r = 0.99). The actual NO concentration from the NO supply cylinder was 1154 ppm and NO2 concentration was 14 ppm. In mongrel dogs, after 20 minutes of NO inhalation (10-100 ppm), the blood methemoglobin level reached a peak value of 2.2% starting from the pre-inhalation level of 0%. To optimize the safety of the clinical application of NO, its concentration should be measured continuously with chemiluminescence technique.

Animals↗
PubMed1994

[Perioperative management of the patient with hypertrophic obstructive cardiomyopathy].

We experienced the perioperative management of a patient with hypertrophic obstructive cardiomyopathy, who underwent open heart surgery. We performed three kinds of overload examinations, which included overdrive test using the pacemaker, continuous dopamine infusion with overdrive test and continuous diltiazem infusion with overdrive test, before and after cardio-pulmonary bypass under observation of the cardiac performances with transesophageal echocardiogram. We gained some important and interesting informations about the cardiac reserve of the patient. We could perform adequate perioperative management for the patient, taking the results of overload examinations into consideration.

Aged↗
PubMed1994

Angiogenic activity of human villi and decidua in the first trimester of pregnancy.

Angiogenic activity in the extracts of human villi and decidua in the first trimester of pregnancy was examined using chorioallantoic membrance assay. Blood vessel density on the chorioallantoic membrane increased greatly with the addition of villi extract, and slightly by decidua extract. Neovascularization with a spoke wheel appearance was induced by both villi and decidua, and this response pattern by the villi was stronger than that by the decidua. Maternal serum did not induce any vascular response. These results suggested that angiogenic activity was present both in the villi and decidua in the first trimester of pregnancy and that the villi activity was stronger than the decidua.

Blood Vessels↗