Biomedical subjects

M Imai

Publications and source records attributed to M Imai.

At least 307 records · Page 17Linked to original sources

PubMed1992

[Direct observation of the epidural space by the superfine fiberscope].

The anatomy of the epidural space was examined in 82 patients 3 to 90 years old who had indications of epidural anesthesia. The superfine fiberscope with an outer diameter of 0.8 mm was utilized for this study. It was advanced through 18 gauge Tuohy needle inserted into the epidural space. All findings were documented by videography. The epidural space was located at the thoracic intervertebral space (52 patients), at the lumbar interspace (27 patients) and at the caudal space (3 patients), using an 18-gauge Tuohy needle with either median or paramedian approach. The epidural space was identified by either hanging drop or loss of resistance method. 65 of 82 cases gave a clear view of epidural space. The epidural space presented as either a space that opened widely or a space that was occupied with large masses of fat. Vessels were encountered on the dura and the flaval ligaments, as well as in the connective tissue. Large amounts of connective tissue were present in all cases. No complications, such as accidental dural puncture, epidural hematoma, infection, nerve injury attributed to this technique were observed.

Adolescent↗

PubMed1992

[A successful treatment of patient with paraquat poisoning].

A 60-year-old man was admitted 1 hour after ingesting approximately 40 ml of Gramoxon (paraquat) in an attempt to commit suicide. Gastrointestinal lavage, compulsory urination, and direct hemoperfusion (DHP) were immediately performed to remove the paraquat. He was then administered Vitamin E and high dose methylprednisolone therapy to prevent lung injury. Chest roentgenogram on the 3rd day showed ground glass appearance in the outer zone of bilateral lung fields. Chest CT scans on the 9th day revealed a faint high density area in the same area, suggesting interstitial change. The shadows gradually improved and had disappeared on the 35th day after admission. Serum superoxide dismutase (SOD) activity, measured by electron spin resonance spectroscopy, was undetectably low until the 22nd day, and then increased into the normal range. It was suggested that SOD was consumed to neutralize the paraquat toxicity. Serum SOD activity changed according to the paraquat activity, and was a useful indicator of paraquat toxic activity. He was discharged without any symptoms 50 days after admission.

Female↗

PubMed1992

[Valve injury: a new complication of internal jugular vein cannulation].

Although internal jugular vein cannulation is performed commonly, most physicians are not aware of existence of the internal jugular venous valve. This is the only valve between the right atrium of the heart and the brain, and it has an important role of preventing retrograde blood flow and increased back pressure to the brain. In this study, anatomic appearance of human internal jugular valves is described, and the competence of these valves is assessed. We examined also a safe approach to percutaneous cannulation of the internal jugular vein to avoid this complication. In the cadaveric subjects, the internal jugular vein with its valve was removed at the time of autopsy. In the living subjects, to examine the movement of this valve, endoscopic visualization utilizing the superfine fiberscope, and ultrasound techniques were applied. Next, to detect the competence of the jugular venous valve, transvalvular pressure gradients were measured. Nineteen internal jugular valves were obtained from 20 cadaveric subjects. These valves were situated directly above the termination of the internal jugular vein into the inferior bulb. The opening and closing of the valve were easily visualized with both superfine fiberscope and real-time ultrasound technique. Patients with competent valves showed transvalvular pressure gradients of 50-100 mmHg during cough-induced high intrathoracic pressure. Internal jugular venous valve is located 0.5-2.0 cm above the union of the subclavian and internal jugular veins, and the central approach performed at the summit of the cervical triangle has been shown to have a risk of injuring the internal jugular venous valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization, Peripheral↗

PubMed1992

[Control of blood pressure by a calcium antagonist during cataract surgery].

The authors evaluated the systemic and ocular hypotensive effects of nicardipine hydrochloride (Perdipine:NH) in 31 cases with acute hypertension (over 160/95 mmHg) during cataract surgery. All cases received an intravenous bolus injection of NH 30 micrograms/kg. Blood pressure and intraocular pressure were compared with level at rest, a preoperatively and 5 minutes after the administration of NH. Blood pressure significantly elevated from 136.9 +/- 10.6/73.4 +/- 10.2 mmHg at rest to 187 +/- 11.5/98 +/- 13.1 mmHg preoperatively (p less than 0.001), but it significantly reduced to 125.6 +/- 13.1/67.1 +/- 8.3 mmHg 5 minutes after the administration of NH (p less than 0.001). On the other hand, in the same way an blood pressure changed, intraocular pressure significantly elevated from 13.3 +/- 2.8 mmHg at rest to 19.8 +/- 2.9 mmHg preoperatively (p less than 0.001), but significantly reduced 17.1 +/- 3.0 mmHg 5 minutes after administration of NH (p less than 0.001). The hypotensive effect of NH continued for over 90 minutes. There were no side effects apart from mild tachycardia in all cases. NH is safe, easy to administer and useful for control of acute hypertension during limited-period surgery such as cataract surgery.

Aged↗

PubMed1992

Cardiac fibroma. Long-term fate after excision.

Between 1980 and July 1983 three infants and children with cardiac fibromas underwent surgical resection at Kobe Children's Hospital. Two of them survived and have an excellent clinical result 6 years and 7 years postoperatively. The results of late follow-up with the use of 24-hour dynamic electrocardiography, two-dimensional echocardiography, thallium-201 myocardial scintillation scan, and technetium 99m sodium pertechnetate-gated blood pool imaging have proved that the patients are free of arrhythmic episodes, free of recurrence of tumor, have no significant myocardial perfusion defect, and have normal left ventricular function.

Child↗

PubMed1991

Structural differences in 5'-flanking regions of rat cytochrome P-450aldo and P-450(11) beta genes.

Two rat genomic clones, one for cytochrome P-450aldo and the other for P-450(11) beta, were isolated and characterized. The two genes, encoding structurally homologous proteins, were closely similar in their intron-exon organizations. Their 5'-flanking regions, however, contained only a few homologous regions. A putative cyclic AMP responsive element, TGACGTGA, was found in the P-450aldo gene, but this sequence was altered at two positions in the P-450(11) beta gene. S1 nuclease protection assay revealed a single transcription initiation site for the P-450aldo gene, while multiple sites were found for the P-450(11) beta gene. These results suggest that transcriptional regulation of the rat P-450aldo and P-450(11) beta genes is due to differences in the sequences of their 5'-flanking regions.

Animals↗

PubMed1991

Effects of exposure to sulfate aerosols and antigen on breathing curve patterns of guinea pigs.

We investigated the effects of ammonium sulfate aerosols on asthmatic dyspnea (immediate type) induced by repeated inhalation of a mixture of bovine serum and egg albumin and on the nonspecific responsiveness of the airway tract to acetylcholine. Guinea pigs were exposed to sulfate aerosol in concentrations of 0.2, 0.4, and 2.0 mg/m3 and to 0.2 mg/m3 sulfate aerosol combined with 0.1 ppm of SO2. The exposure time was 2 h/d, 5 d/wk, 38 times in all. The animals were successively exposed to aerosol (for 2 h) and, after 30 min, to the spraying of albumin solution 3 times per week, 7 or 9 times in all. Breathing curves were continuously recorded by a body plethysmograph system during the sensitization periods. The experiments showed that the degree of asthmatic dyspnea in guinea pigs was increased by the exposure to aerosol, and that there is a quantitative relation between the severity of the dyspnea and extent of the exposure. Exposure in the combination with SO2 showed no effect at the concentration studied. Following the exposure experiment, each group of animals was exposed to the spraying of acetylcholine. The sensitivity to acetylcholine increased at aerosol concentrations of 0.4 and 2.0 mg/m3.

Acetylcholine↗

PubMed1991

Tissue distribution of mouse mammary tumor virus (MMTV) antigens and new endogenous MMTV loci in Japanese laboratory mouse strains.

The distribution of mouse mammary tumor virus (MMTV) antigens was studied by the immunoperoxidase method in the II-TES and I-TES mouse strains as well as their progenitors, CS and DBA/2 strains. In the II-TES, I-TES and CS strains, and BALB/c mice foster-nursed with these strains, MMTV antigens were found not only in epithelial cells of the mammary glands but also in those of other tissues including the seminal vesicle, vas deferens, epididymis, prostate, parotid, submandibular, lacrimal, sebaceous, and urethral glands. In DBA/2 and BALB/cfDBA/2 mice, however, the MMTV antigens were found only in the mammary glands. Electron microscopic examination showed MMTV particles in these organs. When we examined the presence of Mtv-1 and 2 proviruses, which are known to be responsible for MMTV expression, in the genomes of the II-TES, I-TES, CS and DBA/2 strains by Southern blotting, Mtv-2 was not found in any of the mice and Mtv-1 was found in the II-TES and DBA/2 mice but not in the I-TES and CS mice. Instead, four new endogenous MMTV loci, which have never previously been reported in laboratory mouse strains, were detected in the genomes of the II-TES, I-TES and CS strains. One (designated Mtv-42) was common in the three strains and the other three (designated Mtv-43, 44 and 45) were common in the II-TEX and I-TES strains or the II-TES and CS strains. These results thus suggest that new endogenous MMTV loci may be responsible for MMTV expression in a variety of tissues of these three strains.

Animals↗

PubMed1991

Evaluation of the antimicrobial activity of methylglyoxal bis(guanylhydrazone) analogues, the inhibitors for polyamine biosynthetic pathway.

Metabolic and antiproliferative effects of methylglyoxal bis(butylamidinohydrazone) (MGBB) and methylglyoxal bis(cyclopentylamidinohydrazone) (MGBCP), inhibitors for polyamine biosynthetic pathway, on Escherichia coli, Shigella sonnei, Aeromonas sobria, Aeromonas hydrophila and Vibrio cholerae were investigated. MGBB at the concentration of 100 mumol/l depleted intracellular putrescine and spermidine concentrations of E. coli to 25 and 20% of the controls, respectively, while MGBCP depressed their concentrations to 38 and 24%, respectively. In these polyamine-depleted E. coli cells the syntheses of RNA, DNA and protein decreased to 13, 54 and 29% of the control, respectively, with MGBB and to 23, 71 and 55%, respectively, with MGBCP. The minimum inhibitory concentrations (MIC) of MGBB for the growth of A. sobria, E. coli, A. hydrophila, V. cholerae and Sh. sonnei were estimated to be 50, 160, 240, 285 and 320 mumol/l, respectively, whereas those of MGBCP were slightly higher for respective bacteria.

Bacteria↗

PubMed1991

Electrophysiological characterization of upper portion of descending limb of long-looped nephron.

The upper portion of the descending limb of long-looped nephron (LDLu) of the hamster is characterized by high water and ion permeabilities. Although the paracellular route is considered to be the major pathway representing cation permselectivity of this segment, ion transport mechanisms through the transcellular pathway are unknown. To study this issue; we applied cable analysis and conventional microelectrode technique to the hamster LDLu perfused in vitro. The transmural voltage (VT) was not different from zero, and transmural resistance (RT) was very low, 18.3 +/- 2.0 omega.cm2 (n = 12). The basolateral membrane voltage was -80 +/- 2 mV (n = 55), and fractional apical membrane resistance was 0.92 +/- 0.23 (n = 5). Ouabain (0.1 mM) in the bath decreased basolateral membrane voltage (VB) by 23 +/- 3 mV (n = 6, P less than 0.001). Increase in K+ concentration in bath and in lumen from 5 to 50 mM decreased VB by 39 +/- 2 (n = 7, P less than 0.01) and apical membrane voltage (VA) by 10 +/- 1 mV (n = 7, P less than 0.001), respectively. Addition of 2 mM Ba2+ to bath and to lumen decreased VB by -47 +/- 2 (n = 11, P less than 0.001) and decreased VA by 8 +/- 1 mV, respectively. Reduction of HCO3- in bath from 25 to 2.5 mM decreased VB by 4 +/- 1 mV (n = 7, P less than 0.005). Reduction of bath Cl- did not cause any rapid deflection of VB. No appreciable Na+ conductance was detected in the apical membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Effect of protamine on ion conductance of upper portion of descending limb of long-looped nephron from hamsters.

To estimate the contribution of paracellular shunt pathway to the cation-selective permeability in the upper portion of the descending limb of long-looped nephron (LDLu) of hamsters, we observed the effect of protamine on salt-diffusion voltage (delta VT) and transmural resistance (RT). delta VT generated on reduction of lumen NaCl concentration was decreased from 12.0 +/- 1.4 to 7.3 +/- 1.2 mV when 100 micrograms/ml protamine were added to the lumen. Although the effect of protamine persisted after removal of the agent from the lumen, addition of 30 U/ml heparin reversed the delta VT toward the control level. The effect of protamine was dose dependent in the range from 3 to 1,000 micrograms/ml. Protamine was without effect from the bath. Studies on single salt dilution voltage revealed that 100 and 300 micrograms/ml protamine inhibited relative Na+ to Cl- permeability from 4.03 +/- 0.38 to 2.14 +/- 0.21 and from 3.75 +/- 0.37 to 1.36 +/- 0.09, respectively. Protamine markedly decreased the apparent transference number for Na+ but slightly increased the value for Cl-. Protamine also inhibited permeabilities for K+, Rb+, and Li+ relative to Cl-, indicating that the inhibitory effect of protamine was not confined to Na+ but was generalized to cations. Transmural cable analysis showed that 100 micrograms/ml protamine increased RT from 14.0 +/- 1.1 to 19.3 +/- 1.2 omega.cm2, with the effect being reversed by 30 U/ml heparin. Because the effect of protamine on RT was unaffected by ouabain in the bath, changes in RT may mainly represent those of the paracellular shunt resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Interaction of trichlormethiazide or amiloride with PTH in stimulating Ca2+ absorption in rabbit CNT.

To determine the renal tubular site and mechanism of the anticalciuric effects of trichloromethiazide (TCM) and amiloride, we studied the effects of these diuretics on net Ca2+ absorption (JCa) in isolated rabbit connecting tubules (CNT) and cortical collecting ducts (CCD). TCM (100 microM) in the lumen increased JCa in the CNT without affecting lumen-negative transepithelial voltage (VT). This effect was dependent on the amount of parathyroid hormone (PTH, 0.1 or 1 nM) in the bath. TCM had no detectable effect on JCa in the absence of PTH. Addition of 100 microM ouabain to the bath decreased PTH-stimulated JCa and abolished the TCM-stimulated JCa. Elimination of Na+ from the lumen increased PTH-stimulated JCa. Under this condition the ability of TCM to increase JCa was abolished, suggesting that the inhibition of Na+ entry from the lumen with TCM may account for the increase in PTH-stimulated JCa. Elimination of Na+ from the bath in the presence of PTH decreased JCa and abolished the stimulatory effect of TCM on JCa in the presence of PTH. Changes in VT caused by amiloride may not account for the increase in JCa, because JCa was not changed when VT was deflected to more positive direction by increasing bath K+ from 5 to 15 mM. Neither TCM nor amiloride affected JCa in the CCD. From these observations, we speculate that the inhibition of Na+ entry across the apical cell membrane by either thiazides or amiloride may stimulate PTH-induced JCa. The intact Na(+)-Ca2+ antiporter in the basolateral cell membrane is essential for the anticalciuric effect of thiazides and amiloride.

Absorption↗

PubMed1991

Effect of protamine on ion conductance of ascending thin limb of Henle's loop from hamsters.

To evaluate the contribution of paracellular shunt pathway in ascending thin limb (ATL) of hamsters, we examined the effect of protamine, a selective blocker of paracellular conductance, on salt-diffusion voltage (dVT) and transmural resistance (RT) during in vitro microperfusion. Lumen-negative dVT generated on reduction of lumen NaCl concentration was increased further from -7.3 +/- 0.5 to -10.3 +/- 0.7 mV when 300 micrograms/ml protamine was added to the lumen, and calculated Na+/Cl- permeability ratio was decreased from 0.46 +/- 0.03 to 0.31 +/- 0.03. Although the effect of protamine persisted after removal of the agent from the lumen, addition of 30 U/ml heparin returned the dVT toward the control level. The effect of protamine was dose dependent from 30 to 300 micrograms/ml. Protamine also exerted its effect from the bath, and the effect was inhibited by heparin either from the lumen or from the bath. The inhibitory effect was almost the same when the orientation of imposed NaCl gradient was reversed. Inhibition of transcellular Cl- transport with 0.1 mM 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) in the bath caused lumen-positive dVT. This voltage was decreased significantly by protamine. Protamine markedly decreased the apparent transference number for Na+ but slightly increased the value for Cl-. Transmural cable analysis showed that 300 micrograms/ml protamine added to the lumen increased RT from 0.59 +/- 0.10 to 1.20 +/- 0.20 omega.cm2, with the effect being reversed by 30 U/ml heparin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Bactericidal effect of 15-deoxyspergualin on Staphylococcus aureus.

15-Deoxyspergualin (DSG), an immunosuppressive agent used in organ transplantation, exerts metabolic and antiproliferative effects on methicillin- and gentamicin-resistant Staphylococcus aureus and other bacteria (e.g. Sarcina lutea, Bacillus subtilis, Shigella sonnei, Salmonella typhi and Citrobacter freundii). DSG, at the concentration of 20 mg/l, depleted intracellular putrescine and spermidine in S. aureus to 43 and 40% of the controls, respectively. In these polyamine-depleted S. aureus cells, the synthesis of protein, DNA and RNA was decreased to 20, 85, 78% of the controls. The minimal inhibitory concentrations (MIC) of DSG for growth of S. aureus, S. lutea, B. subtilis, S. sonnei, S. typhi and C. freundii were 17, 13, 7, 15, 4, and 29 mg/l, respectively.

Bacteria↗

PubMed1991

Effect of S-8666 on Cl- transport in the rabbit connecting tubule perfused in vitro.

S-8666, [6, 7-dichloro-5-(N, N-dimethylsulfamoyl)-2, 3-dihydrobenzofurancarboxylic acid] is a potent diuretic with uricosuric action. Although the major site of action of S-8666 has been proven by the in vitro microperfusion study to be the thick ascending limb of Henle's loop, clearance studies in the rat suggested that this drug has an additional thiazide-like action. To provide direct evidence that S-8666 acts also on distal nephron segments, we examined effect of S-8666 on Cl- flux across the rabbit connecting tubule perfused in vitro. The drug suppressed the lumen-to-bath Cl- flux by 96 +/- 41 (S.E.)pmol.mm-1.min-1 (n = 9) without affecting transmural voltage. To demonstrate that S-8666 acts on the connecting tubule cell, the target of thiazide diuretics, we compared effects of S-8666 and trichlormethiazide on the basolateral membrane voltage of the connecting tubule cell. Both drugs added to the lumen caused a small but significant hyperpolarization of the basolateral membrane without affecting transmural voltage. We conclude that S-8666 is a unique uricosuric diuretic having actions on both thick ascending limb of Henle's loop and connecting tubule.

Animals↗

PubMed1991

Actual characteristics of the glands distributed in the lamina propria mucosae of the fowl esophagus.

We performed histological and histochemical investigations on the glands distributed in the lamina propria mucosae of the fowl esophagus and demonstrated their actual characteristics. 1. Glandular cells of the compound tubular glands located in the lamina propria mucosae contained a number of fine pepsinogen granules. 2. Reactions to neutral, weak and strong acid mucopolysaccharides, neutral mucus type II and III and sialomucin were evidently positive in these cells. 3. Based on the facts in 1) and 2), we consider that the glands located in the fowl esophagus are undifferentiated gastric glands. 4. The same glands possessed no parietal cells. 5. We demonstrated that the esophageal cardiac glands in the lamina propria mucosae of human esophagus were undifferentiated gastric glands, and they possessed parietal cells. These glands were confirmed in humans alone among the mammalia. 6. The significance of the existence of the same kind of gland in human and fowl esophagus is extremely important. 7. PAS-positive substance in the above-mentioned glands in the fowl esophagus contains sulfuric, acid, neutral mucopolysaccaride and neutral mucus of type II and III but no glycogen. The compound tubular glands distributed in the lamina propria mucosae of the fowl esophagus have been described as mucous glands. We performed histochemical investigation and demonstrated that these glands were undifferentiated gastric glands.

Animals↗

PubMed1991

Proventricular glands in fowl.

Some researchers have already described the fowl proventriculus. However, we believed there was a need for detailed carbohydrate histochemical investigations on the same glands. Moreover, some researchers had erred about the lamina muscularis mucosae. The results of these investigations are as follows. 1. The proventricular glands consist of both superficial and profound gastric glands. 2. The superficial glands are distributed in the lamina propria mucosae while the profound glands exist in the tela submucosa. 3. The superficial glands are simple, branched tubular glands. The columnar glandular cells are arranged in a simple layer and react strongly to PAS, AB (pH 2.5 and 0.5). These appear to be dark purple when they are stained with PAS-AB (pH 2.5). Some other methods have also been tried. 4. Judging from the data 3), the superficial gastric glands contain neutral, weak and strong acids, sulfuric and acid mucopolysaccharides, sialomucin, and II and III neutral mucus type. 5. Glandular cells in the body and basal portions of the superficial gastric glands contain a large number of fine pepsinogen granules. 6. Judging from the data of 3)-5), we believe that the superficial gastric glands are undifferentiated gastric glands and that they are same kinds of glands that are found in mammals. 7. A large number of profound gastric glands fill the tela submucosa. They are compound tubular glands, and are composed of many glandular alveoli. Their columnar glandular cells are arranged in a simple layer. 8. These glandular cells react moderately to PAS, negatively to AB (pH 2.5 and 0.5) and PAS-AB (pH 2.5). Moreover, we observed some other reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Pepsinogen granules in the esophageal epithelium of the rock snake.

We demonstrated a large number of pepsinogen granules in the esophageal pseudostratified ciliated epithelium of the rock snake. 1. The snake esophagus is covered with a pseudostratified ciliated epithelium. 2. This epithelium develop mostly in the upper portion of the esophagus. 3. Long supranuclear portions of the same cells are strongly PAS-positive and contain pepsinogen granules. Those cells possess cilia. 4. The strongly PAS-positive cells and pepsinogen granules decrease or are lost in the middle and lower portions of the esophagus. 5. Glands are distributed in the lamina propria mucosae of the esophagus of the Japanese lizard and gecko. Those in humans and the bird are compound tubular glands and those of the Japanese lizard and gecko are bottle-shaped. The pepsinogen granules of these glands are secreted into the excretory ducts and then discharged into the esophageal lumen. 6. However, the same granules of the snake are contained in the supranuclear portion of the epithelium and are secreted directly into the esophageal lumen. 7. The mode of pepsinogen granule secretion of the esophagus is most simple in the snake.

Animals↗