Biomedical subjects

R Ishii

Publications and source records attributed to R Ishii.

At least 55 records · Page 3Linked to original sources

PubMed1999

Inhibitory effects of hydrolyzable tannins from Melastoma dodecandrum Lour. on nitric oxide production by a murine macrophage-like cell line, RAW264.7, activated with lipopolysaccharide and interferon-gamma.

An extract of Melastoma dodecandrum LOUR. with 80% aqueous acetone (MDL) inhibited nitric oxide (NO) production by a murine macrophage-like cell line, RAW264.7, activated with lipopolysaccharide (LPS) and recombinant mouse interferon-gamma (IFN-gamma). On further fractionation of the extract, the majority of the inhibitory activity was recovered in the 50% methanol extracts, which contained hydrolyzable tannins. Among the latter, casuarinin, casuarictin, pedunclagin and nobotannin B exhibited strong inhibitory activities toward NO production, with ID50 values between 2.0 and 5.1 microM. Both MDL and the purified tannins significantly reduced the induction of the inducible nitric oxide synthase (iNOS) protein in the course of macrophage activation with LPS and IFN-gamma. In addition, the NO production by macrophages preactivated with LPS and IFN-gamma for 16 h was also inhibited by these tannins, with IC50 values around 30-130 microM, but not by MDL. These results suggest that MDL has the pharmacological ability to suppress NO production by activated macrophages and that the hydrolyzable tannins have major inhibitory activities.

Animals↗

PubMed1999

Endosaccular aneurysm occlusion with Guglielmi detachable coils for obstructive hydrocephalus caused by a large basilar tip aneurysm. Case report.

The authors present the case of a 60-year-old man with obstructive hydrocephalus caused by a large basilar artery tip aneurysm, in whom direct surgical clipping of the aneurysm neck was considered hazardous. After endosaccular aneurysm occlusion, his symptoms (headache, intellectual impairment, and gait disturbance) and ventricular dilation immediately improved without placement of a ventricular shunt. To the authors' knowledge, this is the first case of its kind treated solely endovascularly.

Basilar Artery↗

PubMed1999

[Necessity and usefulness of detection by PCR of mecA and aac(6')/aph(2") genes for identification of arbekacin-resistant MRSA].

Arbekacin (ABK)-resistant bacteria (43 strains) isolated as MRSA by regular clinical procedures in Japanese clinics in 1998 were characterized in terms of taxonomic properties, aminoglycoside resistance, and mecA and aac(6')/aph(2") genes linking with ABK-resistant MRSA. Taxonomically the 43 strains fell into Staphylococcus aureus (33 strains) and Enterococcus (10 strains). As to ABK resistance, the 13 strains of MRSA clinically reported as high ABK resistance (128 micrograms/ml or higher) did not show clear high ABK resistance except for 2 strains when their ABK resistance was tested using 0.5% NaCl containing nutrient agar. We designed and established the primers and conditions for PCR to detect the above two resistance genes. PCR analysis of DNAs from the 43 strains clearly indicated that only 33 strains identified taxonomically as S. aureus possessed mecA indicating MRSA and 23 out of them possessed aac(6')/aph(2"). The other 10 strains of MRSA lacking aac(6')/aph(2") were ABK-sensitive. Thus, there were a good correlation between ABK resistance and aac(6')/aph(2") existence. Based on these, it was conclusive that the appropriate ABK resistance test as well as the detection of mecA and aac(6')/aph(2") genes by PCR are necessary and useful to avoid false ABK-resistant MRSA strains.

Acetyltransferases↗

PubMed1998

Effects of moguisteine on the cough reflex induced by afferent electrical stimulation of the superior laryngeal nerve in guinea pigs.

The study aimed to further demonstrate the peripheral antitussive properties of moguisteine. Firstly, the antitussive effect of moguisteine on the cough reflex induced by inhalation of citric acid aerosol was evaluated in conscious guinea pigs. Secondly, the effects of both moguisteine and codeine on the centrally mediated cough reflex induced by afferent electrical stimulation of the superior laryngeal nerve were investigated in anesthetized guinea pigs. Moguisteine (2.5-10 mg/kg, intravenously, i.v.) reduced the cough reflex induced by 7.5% citric acid aerosol in a dose-dependent manner, with an ED50 value of 0.55 mg/kg. Both i.v. (0.5-4 mg/kg) and intracerebroventricular (i.c.v., 5-20 microg) injection of codeine dose dependently inhibited the cough reflex induced by afferent electrical stimulation of the superior laryngeal nerve; the ED50 values were 0.91 mg/kg and 7.90 microg, respectively. The inhibitory effect of codeine (4 mg/kg i.v.) was abolished by pretreatment with naloxone (2 mg/kg intraperitoneally). In contrast to codeine, neither i.v. (4 and 20 mg/kg) nor i.c.v. (20 microg) injection of moguisteine affected the cough reflex. These results suggest that the antitussive effect of codeine is mediated by central opioid mechanisms, whereas the antitussive effect of moguisteine is mediated by peripheral mechanisms.

Aerosols↗

PubMed1998

Simultaneous determination of five macrolide antibiotics in meat by high-performance liquid chromatography.

A simple and rapid method using high-performance liquid chromatography (HPLC) for the simultaneous determination of five macrolides (josamycin, kitasamycin, mirosamicin, spiramycin and tylosin) in meat has been developed. The drugs were extracted with 0.3% metaphosphoric acid-methanol (7:3, v/v), and the extracts were cleaned up on a Bond Elut SCX (500 mg) cartridge. The HPLC separation was performed on a Puresil 5C18 column (150 x 4.6 mm I.D.) with a gradient system of 0.025 M phosphate buffer (pH 2.5)-acetonitrile as the mobile phase at a flow-rate of 1.0 ml/min. The drugs were detected at 232 mn for josamycin, kitasamycin, mirosamicin and spiramycin, and 287 mn for tylosin. The calibration graphs were rectilinear from 2.5 to 100 ng for each drug. The recoveries at the level of 1.0 microgram/g were 70.8-90.4%, and detection limits were 0.05 microgram/g for each drug.

Animals↗

PubMed1998

Brainstem lesion in Aicardi-Goutières syndrome.

Aicardi-Goutières syndrome is characterized by the calcification of basal ganglia, leukodystrophy, and lymphocytosis in cerebrospinal fluid. No brainstem lesion has been described. We report a Japanese girl who presented with delayed development and microcephalus at early infancy. Magnetic resonance imaging revealed T2-weighted high intensity in the cerebral white matter and brainstem, and nerve conduction velocity was delayed in the central nervous system, indicating that she manifested dysmyelination in the brainstem white matter similar to that in the cerebral white matter.

Basal Ganglia Diseases↗

PubMed1998

Unequal cleavage in the early Tubifex embryo.

Unequal cleavage that produces two blastomeres of different size is a cleavage pattern that many animals in a variety of phyla, particularly in Spiralia, adopt during early development. This cleavage pattern is apparently instrumental for asymmetric segregation of developmental potential, but it is also indispensable for normal embryogenesis in many animals. Mechanically, unequal cleavage is achieved by either simple unequal cytokinesis or by forming a polar lobe at the egg's vegetal pole. In the present paper, the mechanisms for unequal cytokinesis involved in the first three cleavages in the oligochaete annelid Tubifex are reviewed. The three unequal cleavages are all brought about by an asymmetrically organized mitotic apparatus (MA). The MA of the first cleavage is monastral in that an aster is present at one pole of a bipolar spindle but not at the other. This monastra form, which arises as a result of the involvement of a single centrosome in the MA assembly, is both necessary and sufficient for unequal first cleavage. The egg cortex during the first mitosis is devoid of the ability to remodel spindle poles. In contrast to the non-cortical mechanisms for the first cleavage, asymmetry in the MA organization at the second and third cleavages depends solely on specialized properties of the cell cortex, to which one spindle pole is physically connected. A cortical attachment site for the second cleavage spindle is generated de novo at the cleavage membrane resulting from the first cleavage; it is an actin-based, cell contact-dependent structure. The cortical microtubule attachment site for the third cleavage, which functions independently of contact with other cells, is not generated at the cleavage membrane resulting from the second cleavage, but is located at the animal pole; it may originate from the second polar body formation and become functional at the 4-cell stage.

Animals↗

PubMed1998

Magnetic resonance imaging of non-specific inflammatory granulation involving the skull base--two case reports.

A 55-year-old male presented with a 20-day history of nuchal pain and hypoglossal nerve paresis on the right. T2-weighted magnetic resonance (MR) imaging showed an isointense lesion with a small hypointense part in the hypoglossal canal and caudal clivus. A 66-year-old female presented with a long-standing history of left orbital pain. T2-weighted MR imaging showed a hypointense lesion occupying the orbital apex which on recurrence became isointense. The histological diagnosis of both lesions was non-specific inflammatory granulation. The T2-weighted MR imaging appearance of this entity is variable, and can change within the clinical course of the same lesion.

Aged↗

PubMed1998

Cerebral mycotic aneurysm treated with endovascular occlusion--case report.

A 56-year-old male with two mycotic aneurysms associated with infective endocarditis was treated by endovascular surgery before mitral valve replacement. Angiography revealed a ruptured proximal aneurysm and an unruptured distal aneurysm on the right middle cerebral artery. The ruptured aneurysm was successfully treated with an interlocking detachable coil, and patency of the parent artery was preserved. The unruptured distal aneurysm disappeared as a result of antibiotic therapy. Endovascular surgery of the mycotic aneurysm is less invasive and more effective than craniotomy under general anesthesia for patients with infective endocarditis.

Aneurysm, Infected↗

PubMed1998

Changes in plasma and urinary norepinephrine following transdermal clonidine in spontaneously hypertensive rats.

To support a long-lasting antihypertensive effect of transdermal clonidine (CAS 4205-90-7), changes in plasma norepinephrine (NE) levels and urinary NE excretion as indices of the sympathetic nervous activities were investigated following transdermal and oral clonidine in conscious spontaneously hypertensive rats. Plasma NE levels were significantly reduced for 24 h during transdermal application of clonidine patch at 1.5 and 4.5 mg/kg on the back of each rat. Oral clonidine at 100 microgram/kg also lowered plasma NE levels. However, significant falls in the levels lasted only for 4 h after oral dosing. Urinary NE excretion was significantly decreased during both 4-8 and 8-24 h periods, and during an 8-24 h period following transdermal clonidine at 1.5 and 4.5 mg/kg, respectively. Significant decrease in urinary NE excretion was also produced during a 4-8 h period following oral clonidine at 100 micrograms/kg. Total urinary NE excretion during a 0-24 h period was dose-dependently reduced following transdermal clonidine, but was not altered following oral dosing. These findings suggest that the sympathoinhibitory effect of transdermal clonidine is more persistent than that of oral clonidine. Therefore, long-lasting antihypertensive effect of transdermal clonidine is closely associated with the sustained suppression of the sympathetic nervous activity.

Administration, Cutaneous↗

PubMed1998

[Relationship between visual field loss and retinal nerve fiber layer thickness in open-angle glaucoma].

We studied the correlation between retinal nerve fiber layer thickness and visual field loss in 117 eyes of 62 patients with open angle glaucoma using the Aulhorn Classification as modified by Greve. We divided the peripapillary area into four quadrants [superior (S), inferior (I), temporal (T), nasal (N)] and the total (T0), and measured the peripapillary retinal nerve fiber layer thickness (NFLT) with a confocal scanning laser polarimeter (Nerve Fiber Analyzer). We also obtained the relative ratios (mean ratios) of the total circumference to the nasal quadrant (T0/N), the superior to the nasal quadrant (S/N), the temporal to the nasal quadrant (T/N), the inferior to the nasal quadrant (I/N), the total to the temporal quadrant (T0/T), the superior to the temporal quadrant (S/T), the nasal to the temporal quadrant (N/T), and the inferior to the temporal quadrant (I/T). Significant decreases were observed in the mean ratios to the temporal quadrant, i.e., T0/T, S/T, and I/T, in stages I to VI when compared with stage 0. However, no significant differences were observed among stages I to VI. These results suggest that these parameters may not precisely reflect the progression of the disease, but may aid differential diagnosis of the early stage (stage 0) from the middle and late stages (stages I to VI).

Female↗

PubMed1998

[Relationship between the retinal nerve fiber layer thickness and the effect of aging in normal eyes].

We studied the correlation between the thickness of the retinal nerve fiber layer and the role of age in 155 normal eyes of 83 subjects without significant ocular diseases. Subjects with a refractive error exceeding +/- 5 diopters were excluded. We divided the peripapillary area into four quadrants: superior (S), inferior (I), temporal (T), and nasal (N). We measured peripapillary retinal nerve fiber layer thickness (NFLT) in these four quadrants and in the total area (T(o)) using a confocal scanning laser polarimeter (Nerve Fiber Analyzer), and determined the correlation coefficients. The retinal nerve fiber layer thickness of the total area and of the four quadrants was not significantly associated with an increase in age. Since changes in the thickness were small in the nasal and temporal quadrants, we measured the relative ratios of the thickness in each quadrant to that in the nasal and temporal quadrants. The ratio of the total area to the nasal quadrant (T(o)/N), the superior to the nasal quadrant (S/N), the inferior to the nasal quadrant (I/N), the total area to the temporal quadrant (T(o)/T), the superior to the temporal quadrant (S/T), and the inferior to the temporal quadrant (I/T) was significantly associated with an increase in age. Multiple comparison in each age group revealed no age-related significant decreases in any of the parameters. These findings suggest that these parameters may reflect the degree of aging in normal eyes, but age-related abnormality in the retinal nerve fiber layer thickness may be small.

Adult↗

PubMed1998

[Sevoflurane anesthesia for myotonic dystrophy].

We successfully anesthetized a 14-year-old boy with myotonic dystrophy for orthopedic surgery using sevoflurane. Sevoflurane enabled anesthetic induction and tracheal intubation without intravenous anesthetics and muscle relaxants. Sevoflurane also provided stable anesthetic maintenance without intravenous anesthetics. The patient showed rapid anesthetic recovery and adequate spontaneous breathing. We conclude that sevoflurane is a useful anesthetic for patients with myotonic dystrophy.

Adolescent↗

PubMed1997

Equalization of unequal first cleavage in the Tubifex egg by introduction of an additional centrosome: implications for the absence of cortical mechanisms for mitotic spindle asymmetry.

The first cleavage in the Tubifex egg is unequal and involves a monastral mitotic apparatus (MA), which remains at the egg's center from metaphase through telophase. The monastral form of the MA is thought to arise due to the involvement of a single maternal centrosome in the MA assembly (R. Ishii and T. Shimizu, Dev. Growth Differ. 37, 687-701, 1995). To investigate the mechanisms that generate asymmetry in this division, we have examined the cleavage patterns in eggs that are manipulated to inherit two centrosomes during the first mitosis. When eggs are prevented from extruding polar bodies, centrosomes located at both poles of the first meiotic spindle persist into the first mitosis without showing any sign of duplication and generate astral spindle poles. Eggs that inherit these centrosomes exhibit two types of MA configurations, viz., an amphiastral MA and twin monastral MAs. We found that eggs with amphiastral MAs undergo bipolar equal divisions, while those with twin MAs divide into three cells simultaneously (tripolar divisions). The amphiastral MAs are located at the egg's center and their astral poles are organized symmetrically, suggesting that Tubifex eggs are unable to generate asymmetry in the amphiastral MAs during the first mitosis. These results suggest that inheritance of a single centrosome during the first mitosis is critical for Tubifex eggs to undergo unequal cleavage. We propose that the cortical mechanisms for MA asymmetry are lacking in the Tubifex egg during the first mitosis.

Animals↗

PubMed1997

Three-dimensional combined flaps for reconstruction of complex facial defects following cancer ablation.

Instead of conventional multiple-paddle or folded free flaps, the authors introduce three types of free combined tissue transfers for cosmetic and functional restoration of massively large facial defects. Three cases reported here were repaired with combined flaps consisting of two or more tissues, such as combined free anterolateral thigh flaps and vascularized muscle or bone grafts. In cases with complex defects in the upper lateral face, facial dynamics were also reconstructed with a free vascularized innervated muscle graft. A complex hemifacial defect involving the orbita and nose can be easily reconstructed with free osteocutaneous flaps in two stages. For complex craniofacial defects, the concept of combined chimeric tissue transfers is most suitable. The ideal pedicle vessels for the combined flaps are considered to be those in the lateral circumflex femoral system, which is far from the head and neck regions, because flap elevation can proceed simultaneously with tumor resection.

Aged↗

PubMed1997

Effects of magnesium sulphate on atrioventricular conduction times and surface electrocardiogram in dogs anaesthetized with sevoflurane.

We have studied the effects of magnesium on atrioventricular (AV) conduction times and surface electrocardiogram during both sinus rhythm and atrial pacing in seven dogs anaesthetized with 1 MAC of sevoflurane. A bolus dose of magnesium sulphate (MgSO4) 30, 60 and 90 mg kg-1 significantly increased plasma magnesium concentrations from 1.3 (SEM 0.1) to 15.3 (1.3) mg dl-1. MgSO4 significantly prolonged A-H (AV nodal conduction time during sinus rhythm), St-H (intra-atrial and AV nodal conduction time during atrial pacing) and H-S (total ventricular conduction time) intervals at doses > or = 30 mg kg-1 ; H-V interval (His-Purkinje conduction time) at doses > or = 60 mg kg-1; RR and PR intervals and QRS duration at doses > or = 30 mg kg-1 in a dose-related manner during both sinus rhythm and atrial pacing. QTc interval remained unchanged during sinus rhythm. The doses of MgSO4 used did not have deleterious effects on AV conduction times and surface electrocardiogram during 1 MAC of sevoflurane anaesthesia. This finding suggests that MgSO4 in high doses was safe and may be indicated for cardiac arrhythmia and hypertension during sevoflurane anaesthesia. However, further study is required to apply these findings to clinical anaesthesia.

Anesthetics, Inhalation↗

PubMed1997

Effects of magnesium sulphate on the cardiovascular system, coronary circulation and myocardial metabolism in anaesthetized dogs.

We have studied the effects of i.v. bolus doses of magnesium sulphate (MgSO4) 60, 90 and 120 mg kg-1 on haemodynamic state, the coronary circulation and myocardial metabolism in nine dogs anaesthetized with pentobarbitone and fentanyl. MgSO4 produced dose-dependent decreases in arterial pressure, heart rate, left ventricular dP/dtmax and left ventricular minute work index (LVMWI) and an increase in the time constant of left ventricular isovolumic relaxation. Stroke volume increased, systemic vascular resistance decreased and cardiac output did not change significantly. MgSO4 produced decreases in coronary perfusion pressure, coronary vascular resistance and myocardial oxygen consumption (MVO2). Coronary sinus blood flow, lactate extraction ratio and the ratio of LVMWI to myocardial MVO2, that is an index of cardiac efficiency, did not change significantly. This study indicated that the depressant effect of MgSO4 on cardiac function was offset by lowering of peripheral vascular resistance, so that cardiac pump function remained effective, and the almost constant coronary sinus blood flow resulted from the decrease in coronary vascular resistance even at higher doses.

Animals↗

PubMed1997

Inclusion of trithia[5]heterohelicene by various serum albumins. An effective probe for chiral discrimination.

Racemic 2-hydroxymethyltrithia[5]heterohelicene (2-HT), which has a labile helical structure was incorporated into serum albumins of nine species in 1% ethanolic aqueous solution, giving 1:1 complexes which exhibited induced circular dichroism spectra with species specificity. The application of 2-HT to bovine serum as a probe for chiral recognition revealed that the serum itself manifested an apparent chiral discrimination between enantiomers of 2-HT.

Animals↗