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Biomedical subjects

N Fujimura

Publications and source records attributed to N Fujimura.

At least 19 recordsLinked to original sources
PubMed2003

Preoperative selective internal carotid artery dural branch embolisation for petroclival meningiomas.

We assessed the clinical value of preoperative embolisation of the dural branches of the internal carotid artery (ICA) in cases of petroclival meningioma was evaluated. We carried out preoperative selective embolisation on seven consecutive patients with large petroclival meningiomas, using nonbraided 2 F steam-shaped microcatheters and shapeable hydrophilic microguide-wires to enter the dural branches of the ICA. The embolisations were performed using digital subtraction fluoroscopy with 150-250 microm polyvinyl alcohol particles. The tumours were resected a few days after embolisation. We reviewed angiographic findings before and after endovascular devascularisation, blood loss during tumour resection and clinical outcome. All endovascular procedures were technically successful, and postembolisation angiography showed disappearance of or marked decrease in tumour stain in all cases. Intraoperative bleeding was easily controlled, and intraoperative blood loss was low.

Adult↗
PubMed2001

[Swelling of the tongue after intraoperative monitoring by transesophageal echocardiography].

Tongue swelling after surgery is a rare but potentially lethal postoperative complication. This is a case report of a 62-yr-old patient who developed tongue swelling after intraoperative monitoring by transesophageal echocardiography. The patient underwent replacement of the descending aorta with an interposition graft under cardiopulmonary bypass. A transesophageal echocardiography (TEE) probe was inserted after the induction of general anesthesia. Surgery and anesthesia were uneventful. After the surgical procedure, the TEE probe was removed. At that time, marked swelling of the tongue was noted. However, there was no diffuse edema in the neck, face, supraglottic structures or the larynx. The tongue swelling was thought to have been caused by local mechanical compression of the tongue with the TEE probe. The tongue returned to normal size the next day. Care should be taken to prevent the occurrence of this complication during and after TEE examination under general anesthesia.

Echocardiography, Transesophageal↗
PubMed2000

Dilated rough endoplasmic reticulum corresponding to septate cytoplasmic vacuoles in papillary thyroid carcinoma.

Septate cytoplasmic vacuoles, which are one of the cytologic findings characteristic of papillary thyroid carcinoma, are small, uniform, and well-defined vacuoles, with defined strands of cytoplasm separating them. We report on a case with histologic and ultrastructural findings corresponding to septate cytoplasmic vacuoles, which have not been previously described. The patient was a 51-yr-old man with a mass in the left anterior of the neck, measuring 4.0 x 3.5 cm in diameter. Aspiration cytology smears revealed findings typical of papillary thyroid carcinoma, including papillary tissue fragments, intranuclear inclusions, nuclear grooves, powdery chromatin, and psammoma bodies. The tumor cells which were located at the periphery of small three-dimensional clusters, and others which showed a sheet-like arrangement, demonstrated uniform, small vacuoles in relatively abundant, dense cytoplasm. Histologically, a small number of papillary thyroid carcinoma cells with multiple vacuoles were observed, which were limited to the hobnail-shaped cells located at papillary configurations or floating tumor cells within the papillary lumen. Ultrastructurally, the hobnail-shaped tumor cells demonstrated various-sized dilated rough endoplasmic reticulum and rich heterochromatin. We emphasize that septate cytoplasmic vacuoles correspond to dilated rough endoplasmic vacuoles and are probably related to degenerative changes.

Carcinoma, Papillary↗
PubMed2000

Purification and characterization of organic solvent-stable lipase from organic solvent-tolerant Pseudomonas aeruginosa LST-03.

An organic solvent-stable lipase (LST-03 lipase) secreted into the culture broth of the organic solvent-tolerant Pseudomonas aeruginosa LST-03 was purified by ion-exchange and hydrophobic interaction chromatography in the presence of 2-propanol. The purified enzyme was homogeneous as determined by SDS-PAGE. The molecular mass of the lipase was estimated to be 27.1 kDa by SDS-PAGE and 36 kDa by gel filtration. The optimum pH and temperature were 6.0 and 37 degrees C. LST-03 lipase was stable at pH 5-8 and below 40 degrees C. Its hydrolytic activity was highest against tricaproin (C6), methyl octanoate (C8), and coconut oil respectively among the triacylglycerols, fatty acid methyl esters, and natural oils investigated. The enzyme cleaved not only the 1,3-positioned ester bonds, but also the 2-positioned ester bond of triolein. It exhibited high levels of activity in the presence of n-decane, n-octane, DMSO, and DMF as well as in the absence of an organic solvent. In addition, LST-03 lipase was stabler in the presence of n-decane, ethyleneglycol, DMSO, n-octane, n-heptane, isooctane, and cyclohexane than in the absence of an organic solvent.

Journal Article↗
PubMed2000

Propofol enhances a d-tubocurarine-induced twitch depression in septic rat diaphragm.

UNLABELLED: We estimated the effect of d-tubocurarine (dTc) on neuromuscular transmission and the action of propofol on dTc-induced twitch depression by using sham control and septic rat nerve-hemidiaphragm preparations in vitro. Isometric twitch tension elicited by indirect (phrenic nerve) or direct (muscle) stimulation at 0.1 Hz was evaluated. Sepsis induced by panperitonitis attenuated the twitch tension elicited by indirect and direct stimulation (P < 0.01 in each group) in the absence of significant morphological inflammatory damage to the diaphragm. dTc (1 microM) decreased the twitch tension elicited by indirect stimulation (P < 0.01) less intensely in the septic group than in the sham group (P < 0.01). Propofol accentuated dTc-induced depressed twitch more intensely in the septic group (P < 0.01 or 0.05). These results demonstrate that sepsis attenuates both muscle contractile force and the effect of a neuromuscular blocker and that propofol more intensely enhances dTc-induced twitch depression during sepsis. IMPLICATIONS: Propofol and nondepolarizing muscle relaxants are widely used for various clinical cases, including sepsis. Interactions between nondepolarizing muscle relaxants and propofol during sepsis are interesting from a clinical point of view. We demonstrated that propofol significantly enhances d-tubocurarine-induced twitch depression in vitro in the septic rat model compared with that in the nonseptic rat model.

Anesthetics, Intravenous↗
PubMed2000

Alteration in diaphragmatic contractility during septic peritonitis in rats: effect of polyethylene glycol-absorbed superoxide dismutase.

OBJECTIVES: To assess the alterations in diaphragmatic contractility measured in vitro during experimental septic peritonitis and to evaluate the effect of polyethylene glycol-absorbed superoxide dismutase (PEG-SOD) on the alterations in contractility. DESIGN: Prospective, randomized, controlled animal trial. SETTING: Research laboratory. SUBJECTS: A total of 321 male Wistar rats, weighing 250-300 g. INTERVENTIONS: Rats were treated with cecal ligation and puncture (CLP). In the first experiment, diaphragmatic contractility was measured at 4, 10, 12, and 16 hrs after CLP. In the second experiment, PEG-SOD (4,000 units/kg) was administered intraperitoneally, and then diaphragmatic contractility was measured at 10 and 16 hrs after CLP. Levels of lipid peroxides and antioxidant enzymes in the diaphragm tissue were measured at 10 and 16 hrs after CLP. MEASUREMENTS AND MAIN RESULTS: In experiment 1, diaphragmatic twitch characteristics and force-frequency relationships were determined at 4, 10, 12, and 16 hrs after CLP. In experiment 2, the effects of administration of PEG-SOD on twitch characteristics and force-frequency relationships were determined at 10 and 16 hrs after CLP. The levels of diaphragmatic thiobarbituric acid reactive substances and superoxide dismutase (SOD) and glutathione peroxidase activities were measured at 10 and 16 hrs after CLP. Twitch tension and force-frequency curves were significantly lower in the CLP groups than in the sham-operated group. Administration of PEG-SOD attenuated the reduction in twitch tension and the downward shift of force-frequency curves after CLP. Diaphragmatic levels of thiobarbituric acid reactive substances increased after CLP. However, the administration of PEG-SOD prevented increases in levels of diaphragmatic thiobarbituric acid reactive substances after CLP. Diaphragmatic SOD activity, but not glutathione peroxidase activity, was increased after CLP. CONCLUSIONS: Intra-abdominal sepsis (CLP) induced a marked reduction in diaphragmatic contractility, but PEG-SOD attenuated this reduction. Therefore, we conclude that oxygen-derived free radicals play an important role in the alterations in diaphragmatic contractility during intra-abdominal sepsis.

Animals↗
PubMed2000

Pathology and pathophysiology of pneumoconiosis.

Cellular and molecular mechanisms, as well as associated gene expressions, in silicosis and asbestosis are widely investigated, and compound mechanisms involved in initiating inflammation and progression to fibrosis are comprehensively studied, though not yet totally understood. Recent advances in this field, especially concerning pathophysiology of these pneumoconioses, are reviewed in this article. Silicosis and asbestosis are two major types of pneumoconiosis. Although the clinico-pathologic features presented are apparently different, silicosis and asbestosis are both interstitial lung diseases caused by chronic exposure to airborne inorganic dusts, and the pathology of these two diseases is essentially a fibrosis.

Asbestosis↗
PubMed2000

Effects of isoproterenol on diaphragmatic contractility in septic peritonitis.

We investigated the effects, and the mechanism of the effects, of isoproterenol on diaphragmatic contractility and fatigue in septic peritonitis in vitro. Ninety-six rats were divided into two groups of 48. One group (CLP group) was treated with cecal ligation and perforation (CLP) and the other (sham group) was treated with laparotomy. The left hemidiaphragm was removed at 16 h after the operation. We assessed the diaphragmatic contractility by twitch characteristics and force-frequency curves in vitro. Diaphragm fatigue was induced by rhythmically stimulating strips to contract at 60/ min (20 Hz, 0.33-s trains, 1 train/s) over a 4-min period. Force-frequency curves were determined before and after fatigue. Isoproterenol (10(-9), 10(-8), and 10(-7) M), a beta-adrenoceptor agonist, was cumulatively administered to the organ bath. Isoproterenol significantly increased diaphragmatic contractility. There were no significant changes in diaphragmatic contractility in the sham group. Isoproterenol (10(-7) M) significantly accelerated diaphragmatic recovery of fatigue and increased cAMP levels both in the sham group and the CLP group. Propranolol (10(-7) M), a general beta-adrenoceptor blocker, completely abolished the positive inotropic effect of isoproterenol (10(-7) M) and increased cAMP levels in the CLP group. Dibutyryl cAMP (10(-3) M), a derivative of cyclic AMP, mimicked the effects of isoproterenol in the CLP group. These results suggest that isoproterenol increases diaphragmatic contractility and accelerates diaphragmatic recovery of fatigue in septic peritonitis by activating the adenylate cyclase system.

Adenylyl Cyclases↗
PubMed2000

Effect of free radical scavengers on diaphragmatic contractility in septic peritonitis.

We investigated the effects of polyethylene glycol-adsorbed superoxide dismutase (PEG-SOD), polyethylene glycol-adsorbed catalase (PEG-CAT), and DMSO on diaphragmatic contractility and malondialdehyde (MDA) concentrations in septic peritonitis in vitro. One hundred eighty-six rats were divided into two groups. One group (CLP group) was treated with cecal ligation and perforation (CLP), and the other (sham group) was treated with laparotomy. PEG-SOD, PEG-CAT, and DMSO were administered intraperitoneally 30 min before and 12 h after CLP. The left hemidiaphragm was removed at 10 h or 16 h after the operation. We assessed the diaphragmatic contractility by twitch characteristics and force-frequency curves in vitro. We measured MDA concentrations, as an index of oxygen-derived free radical-mediated lipid peroxidation, and the activities of two main antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPx), as an index of antioxidant defenses, after CLP. Diaphragmatic force generation capacity was significantly reduced after CLP. Diaphragmatic MDA levels were significantly elevated after CLP. PEG-SOD, PEG-CAT, and DMSO significantly improved diaphragmatic contractility and prevented the elevation in diaphragmatic MDA concentrations after CLP. Diaphragmatic SOD activities were significantly increased after CLP. These results suggest that several types of oxygen-derived free radicals play a role in the reduction in diaphragmatic contractility after CLP.

Animals↗
PubMed2000

Intrauterine and intravaginal insemination with frozen canine semen using an extender consisting of orvus ES paste-supplemented egg yolk tris-fructose citrate.

Our previous report indicated that addition of Orvus ES Paste (OEP) to the extender of frozen canine semen protected acrosomes and maintained sperm motility after thawing. In this study, artificial insemination (AI) using the frozen semen was carried out. The frozen semen was prepared using egg yolk Tris-fructose citrate, and the final concentrations of glycerol and OEP were 7% (v/v) and 0.75% (v/v), respectively. AI was performed during the optimal mating period predicted from the peripheral plasma progesterone level. In intrauterine insemination (IUI), the bitches were laparotomized and 1 x 10(8) spermatozoa were infused into one of the uterine horns. In insemination of non-OEP supplemented semen, 3 x 10(8) spermatozoa were inseminated. In intravaginal insemination (IVI), 10-40 x 10(8) spermatozoa were inseminated. Conception was obtained in nine of 10 bitches (90.0%) that underwent IUI. The number of newborns was from 1 to 7 (mean 3.6 +/- 0.9). The mean ratio of the number of puppies to the number of ovulations in the inseminated uterine horn was 71.8%. The number of puppies did not exceed the number of ovulation in the inseminated uterine horn. Conception using non-OEP supplemented frozen semen was unsuccessful in all four bitches. In IVI, conception was not obtained in any of the six bitches that received insemination of 10 x 10(8) or 40 x 10(8) spermatozoa, but two of three bitches that received insemination of 20 x 10(8) spermatozoa were fertilized. It was shown that a high conception rate can be obtained by IUI using OEP-supplemented frozen canine semen. Developmenmt of a non-surgical method of IUI and a method of freezing canine sperm applicable to IVI is necessary.

Animals↗
PubMed2000

[Clinical features and outcomes of mechanically ventilated patients with acute respiratory failure during treatment with immunosuppressive drugs].

We examined clinical features and outcomes of mechanically ventilated patient (n = 11) retrospectively who had developed acute respiratory failure during treatments with immunosuppressive drugs. The mean APACHE II score was 22.6, and the mean lung injury score was 2.9. In eight patients chest X-ray and computed tomography showed interstitial pneumonia. Fungus and/or cytomegalovirus were isolated most often from patients with interstitial pneumonia. Observed mortality (72.7%) was significantly (P < 0.001) higher than predicted mortality (45.1%) in the APACHE II score. Patients, who were complicated with septic shock caused by fungus infection, showed poor mortality. These results suggest that the fungus and cytomegalovirus infections might be associated with poor prognosis in patients with acute respiratory failure during treatment with immunosuppressive drugs.

Acute Disease↗
PubMed1999

Sepsis attenuates the intensity of the neuromuscular blocking effect of d-tubocurarine and the antagonistic actions of neostigmine and edrophonium accompanying depression of muscle contractility of the diaphragm.

BACKGROUND: Prolonged effects of non-depolarizing muscle relaxants in septic patients have been reported, although the influence of sepsis on neuromuscular transmission has not yet been clarified satisfactorily. These studies were intended to elucidate the influence of sepsis on neuromuscular transmission and on the action of drugs being utilized for regulation of muscle tone (a neuromuscular blocker and anti-cholinesterase (anti-ChE) drugs). METHODS: The effect of d-tubocurarine (dTc) on neuromuscular transmission and the antagonistic action of anti-ChE drugs (neostigmine and edrophonium) on dTc-induced twitch depression were estimated using sham control and septic rat nerve-hemidiaphragm preparations in vitro. Isometric twitch tension elicited by indirect (phrenic nerve) or direct (muscle) stimulation at 0.1 Hz was evaluated. RESULTS: Sepsis induced by panperitonitis attenuated the twitch tension elicited by indirect or direct stimulation (P < 0.01) without obvious morphological inflammatory damage to the diaphragm. dTc dose-dependently decreased twitch tension elicited by indirect stimulation (P < 0.01) less intensely in the septic group than in the sham group (P < 0.01). The antagonistic actions of the anti-ChE drugs on dTc (1 microM)-induced twitch depression were less intense in the septic group (P < 0.01 or 0.05). CONCLUSION: These results demonstrate that sepsis in the acute phase attenuates the effects of a neuromuscular blocker and anti-ChE drugs and depresses muscle contractility simultaneously.

Animals↗
PubMed1999

Membrane dysfunction induced by in vitro ischemia in immature rat hippocampal CA1 neurons.

We investigated differences between immature and mature hippocampal neurons in their response to deprivation of oxygen and glucose (in vitro ischemia), using intracellular recording techniques from CA1 pyramidal neurons in rat brain slices. The membrane was more depolarized in immature hippocampal CA1 neurons (postnatal day 7, P7) compared with the adult neurons (P140), and the apparent input resistance in immature neurons was higher than that in adult neurons. In immature neurons, the threshold for action potential generation was high, and the peak amplitude of the action potential was low in comparison with adult neurons. A time-dependent inward rectification, at potentials negative than the resting potential, was prominent in neurons of P14 and P21. After P21, the resting membrane potential, the apparent input resistance, and the threshold and the peak amplitude of the action potential did not significantly change with increasing age. In adult neurons, application of ischemia-simulating medium caused irreversible changes in membrane potential consisting of an initial hyperpolarization followed by a slow depolarization and a rapid depolarization. Once the rapid depolarization occurred, reintroduction of oxygen and glucose failed to restore the membrane potential, a state referred to as irreversible membrane dysfunction. In neurons of ages P7 or P14, the initial hyperpolarization was not apparent, whereas a slow depolarization followed by a rapid depolarization was observed. With development of the neurons, the latency for onset of the rapid depolarization became shorter and its maximal slope increased. Moreover, neurons of ages P14 or P21 showed a partial or complete recovery after reintroduction of oxygen and glucose, unlike mature neurons. In summary, the present study has demonstrated that the initial hyperpolarization and rapid depolarization induced by in vitro ischemia is age dependent. The rapid depolarization is not readily produced in the neurons in age less than P21 during ischemic exposure.

Action Potentials↗
PubMed1999

[A case of aneurysmal neck clipping following incomplete neck clipping and coil embolization].

We report a case with radical neck clipping following incomplete embolization with coils and imperfect neck clipping. A 43-year-old woman suffered from a subarachnoid hemorrhage (Hunt & Hess Grade IV) due to the rupture of a left paraclinoid internal carotid aneurysm on 28 October, 1996. Neck clipping of the aneurysm was performed at day 1. Follow-up angiogram at 2 weeks after surgery showed however a small residual aneurysm. The second angiogram 1.5 months later showed the growth of the residual aneurysm. The residual part of the aneurysm was then treated with endovascular embolization using interlocking detachable coils (IDC), resulting in incomplete occlusion of the aneurysm. The direct surgical clipping of the residual aneurysm was performed via Dolenc approach. A fenestrated clip was applied to the partial embolized aneurysm, when the aneurysmal wall was ruptured between the occluded part of the aneurysm and the residual dome. The fenestrated clip was then reapplied successfully under temporary occlusion of the parent artery. Because of the stenosis of the parent artery, STA-MCA anastomosis was then performed. Postoperative recovery of the patient was uneventful and postoperative angiogram showed stenosis of the parent artery with patent bypass flow. The patient was discharged without complications. Technical problems in neck clipping following incomplete embolization with coils are discussed.

Adult↗
PubMed1999

Milrinone, a phosphodiesterase III inhibitor, antagonizes the neuromuscular blocking effect of a non-depolarizing muscle relaxant in vitro.

Phosphodiesterase (PDE) inhibitors are occasionally used in patients receiving non-depolarizing muscle relaxants during anesthesia and intensive care. However, little is known about the influence of PDE III inhibitors on the effects of non-depolarizing muscle relaxants. The aim of this study was to elucidate the effects of milrinone, a PDE III inhibitor, on d-tubocurarine (dTc)-induced muscle relaxation in vitro and then to compare its effects with those of other activators of the adenylate cyclase (AC) system (aminophylline, a non-selective PDE inhibitor; forskolin, a direct AC activator; and isoproterenol, a beta-adrenoceptor agonist). Isometric twitch tensions of rat nerve-hemidiaphragm preparations elicited by indirect or direct stimulation (0.1 Hz) were measured. Indirectly elicited twitch tension partially depressed by dTc (1 microM) was antagonized by milrinone, aminophylline, and forskolin but was attenuated by isoproterenol. Directly elicited twitch tension was increased by aminophylline, forskolin, and isoproterenol but was not altered by milrinone. The results indicate that milrinone antagonizes dTc-induced muscle relaxation by recovering the neuromuscular transmission. It is noteworthy that PDE inhibitors and a beta-adrenergic agonist affect non-depolarizing muscle relaxation in opposite direction.

Adrenergic beta-Agonists↗
PubMed1997

Contribution of ATP-sensitive potassium channels to hypoxic hyperpolarization in rat hippocampal CA1 neurons in vitro.

To investigate the mechanism of generation of the hypoxia-induced hyperpolarization (hypoxic hyperpolarization) in hippocampal CA1 neurons in rat tissue slices, recordings were made in current-clamp mode and single-electrode voltage-clamp mode. Superfusion with hypoxic medium produced a hyperpolarization and corresponding outward current, which were associated with an increase in membrane conductance. Reoxygenation produced a further hyperpolarization, with corresponding outward current, followed by a recovery to the preexposure level. The amplitude of the posthypoxic hyperpolarization was always greater than that of the hypoxic hyperpolarization. In single-electrode voltage-clamp mode, it was difficult to record reproducible outward currents in response to repeated hypoxic exposure with the use of electrodes with a high tip resistance. The current-clamp technique was therefore chosen to study the pharmacological characteristics of the hypoxic hyperpolarization. In 60-80% of hippocampal CA1 neurons, glibenclamide or tolbutamide (3-100 microM) reduced the amplitude of the hypoxic hyperpolarization in a concentration-dependent manner by up to approximately 70%. The glibenclamide or tolbutamide concentrations producing half-maximal inhibition of the hypoxic hyperpolarization were 6 and 12 microM, respectively. The chord conductance of the membrane potential between -80 and -90 mV in the absence of glibenclamide (30 microM) or tolbutamide (100 microM) was 2-3 times greater than that in the presence of glibenclamide or tolbutamide. In contrast, the reversal potential of the hypoxic hyperpolarization was approximately -83 mV in both the absence and presence of tolbutamide or glibenclamide. In approximately 40% of CA1 neurons, diazoxide (100 microM) or nicorandil (1 mM) mimicked the hypoxic hyperpolarization and pretreatment of these drugs occluded the hypoxic hyperpolarization. When ATP was injected into the impaled neuron, hypoxic exposure could not produce a hyperpolarization. The intracellular injection of the nonhydrolyzable ATP analogue 5'-adenylylimidodiphosphate lithium salt reduced the amplitude of the hypoxic hyperpolarization. Furthermore, application of dinitrophenol (10 microM) mimicked the hypoxic hyperpolarization, and the dinitrophenol-induced hyperpolarization was inhibited by either pretreatment of tolbutamide or intracellular injection of ATP, indicating that the hypoxic hyperpolarization is highly dependent on intracellular ATP. It is therefore concluded that in the majority of hippocampal CA1 neurons, exposure to hypoxic conditions resulting in a reduction in the intracellular level of ATP leads to activation of ATP-sensitive potassium channels with concomitant hyperpolarization.

Adenosine Triphosphate↗