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Biomedical subjects

M Umino

Publications and source records attributed to M Umino.

At least 19 recordsLinked to original sources
PubMed2006

Delirium during intravenous sedation with midazolam alone and with propofol in dental treatment.

A 62-year-old man visited our clinic for dental implantation under intravenous sedation. He demonstrated increased psychomotor activity and incomprehensible verbal contact during intravenous sedation. Although delirium caused by midazolam or propofol in different patients has been reported, the present case represents a delirium that developed from both drugs in the same patient, possibly because of the patient's smaller tolerance to midazolam and propofol.

Alveolar Ridge Augmentation↗
PubMed2005

Lidocaine transport through living rat skin using alternating current.

The purpose of the study was to determine whether lidocaine could be transported through living rat skin using alternating current and to determine whether lidocaine transport depends on voltage. The drug delivery cell was originally constructed for the application of an electric field. Hairless rats were anaesthetised using sevoflurane, and a tracheotomy was performed. The drug delivery cell, with lidocaine solution in the donor cell, was placed on the abdominal skin. Samples were collected from the subcutaneous tissue using a microdialysis probe inserted into the abdominal subcutaneous tissue, and the lidocaine concentrations in the samples were determined using high-performance liquid chromatography. The lidocaine concentration in the rat skin increased in time, and voltage-dependency was approximately linear. The lidocaine concentration after the application of 20 V for 21 min was about ten-fold higher than that observed after 21 min of passive diffusion. Lidocaine was successfully transported through living rat skin in a voltage- and time-dependent manner. This drug delivery cell may contribute to local anaesthesia and pain management of human skin.

Administration, Cutaneous↗
PubMed2004

Application of a mandibular nerve block using an indwelling catheter for intractable cancer pain.

We report a case in which a mandibular nerve block using an indwelling catheter was employed for pain management in a terminal case of orofacial cancer. The patient was a 74-year-old female weighing 27 kg. She had a 27-month history of mouth floor and tongue cancer. The cancer recurred and spread to bilateral face and neck. The severest pain mainly originated from the right mandibular region. Two steps of pain relief were performed for the patient. First, pain control using 1% lidocaine or 0.25% bupivacaine administered intermittently or continuously through an indwelling catheter in the mandibular nerve was performed for 1 week to estimate the amount of pain relief thereby obtained. Second, a neurolytic block was applied to the mandibular nerve through the catheter. After the neurolytic block, the total dosage of morphine and diclofenac remained unchanged for 2 months. We conclude from the present case that this technique is an excellent means of obtaining long-term pain control in patients with intractable orofacial cancer pain.

Aged↗
PubMed2003

Decreased bispectral index as an indicator of syncope before hypotension and bradycardia in two patients with needle phobia.

We report two cases who exhibited a decrease in their bispectral index (BIS) score, associated with syncope during venipuncture in patients with suspected needle phobia. In case 1, the reduction in BIS score occurred during the development of hypotension and bradycardia and may well have been caused by cerebral hypoperfusion. In case 2, the patient lost consciousness with decreasing BIS score before hypotension and bradycardia; this patient's condition could not be completely explained by cerebral hypoperfusion as a result of a vasovagal reflex because the patient's blood pressure and heart rate remained normal during the syncopal episode.

Adult↗
PubMed2002

Experimental and theoretical studies of the effect of electrode polarisation on capacitances of blood and potassium chloride solution.

The effects of electrode polarisation on the observed capacitances of electrolytic solutions, including whole blood, plasma and potassium chloride solution, have been investigated experimentally in the frequency region from 10 to 10(5) Hz, by varying the area of the electrodes using plate and mesh electrodes, by varying the electrode distance, and by varying the concentration of KCl in the potassium chloride solution. The effects of the electrode polarisation on the observed capacitances were most significant in the frequencies lower than 10(2) Hz, but cannot be neglected in any frequency region. The so-called alpha dispersion observed in the frequencies lower than about 10(3) Hz was reproduced theoretically with an equivalent circuit model, using constant values independent of frequency for the four circuit parameters: sample capacitance, sample conductivity, electrode polarisation capacitance and electrode polarisation conductivity. It was concluded that the observed alpha dispersion is not a real one that represents the specific features of the samples themselves, but an apparent one that represents the characteristics of the whole measurement system, including the electrode polarisation.

Blood Physiological Phenomena↗
PubMed2002

Intravenous sedation and general anesthesia for a patient with Gilles de la Tourette's syndrome undergoing dental treatment.

Patients with Gilles de la Tourette's syndrome develop symptoms during childhood. Repetitive various motor tics or speech tics that are spontaneous, aimless, and involuntary are characteristic of the syndrome (1). Patients with the syndrome have been considered to have an aggressive, impulsive, and obsessive character (2). (3). Suicide is one of the mental symptoms of the syndrome. Routine dental treatment with this syndrome can be difficult.

Adolescent↗
PubMed2001

A mechanism of the high frequency AC iontophoresis.

The efficiency and the voltage dependence of the AC iontophoresis were studied in vitro. Two cylindrical glass cells separated by a cellophane film were used, where the donor cell was filled with the solution of target electrolytes and the receptor cell with distilled water. The sinusoidal AC voltage with a frequency of 1 kHz was applied between the two platinum plates located at the opposite ends of two cells. The time variation of the ion concentration was evaluated by measuring the impedance of the solution in the receptor cell. The transportation velocity of the ions increased with the amplitude of the voltage applied between two platinum plate electrodes apart 20 mm up to approximately 15 V, and leveled off above approximately 15 V. A theoretical model is proposed on the AC iontophoresis, where each ion moves together with the surrounding water molecules when it is hydrated. The effective Stokes radius of an ion is assumed to be half of the whole size of the ion with hydrating water molecules. When the external alternating electric field strongly vibrates the ion, the ion-dipole interactions between the ion and water molecules are broken, resulting in the reduced effective Stokes radius, which leads to the increase of the diffusion efficiency.

Algorithms↗
PubMed2001

Heterotopic painful stimulation decreases the late component of somatosensory evoked potentials induced by electrical tooth stimulation.

The purpose of this study was to determine the relationship between the late component of somatosensory evoked potentials (SEP) induced by electrical tooth stimulation and subjective pain estimation when heterotopically painful stimulation was delivered to humans. The noxious electrical conditioning stimuli were applied to the left median nerve in noxious session I and the right median nerve in noxious session II for 10 min. The amplitude of the late component and visual analogue scale (VAS) value were both decreased significantly by conditioning stimuli in both sessions. The maximum decreases in SEP amplitude and VAS value induced by conditioning stimuli were respectively 40.2 and 37.2% in noxious session I and 49.3 and 42.3% in noxious session II. After-effect was observed 5 min after removal of the conditioning stimuli. The rates of decrease were thus nearly the same and independent of the site of conditioning stimulation in noxious sessions I and II. The SEP amplitude was significantly correlated with VAS values. The present study revealed that SEP amplitude and subjective pain intensity estimated by VAS following electrical tooth stimulation can be decreased by noxious stimuli to hand. This finding that heterotopic painful stimulation attenuates experimentally-induced tooth pain suggests a triggering of diffuse noxious inhibitory control (DNIC) with after-effect in trigeminal region.

Adult↗
PubMed2000

First example of memory of chirality in carbenium ion chemistry

The non-Kolbe reaction of N-benzoyloxazolidine derivatives 6 derived from L-serine gave optically active N,O-acetals 7 when graphite was used as an anode material. This reaction represents the first example of "memory of chirality" in carbenium ion chemistry. The material used for the anode was critical for the memory of chirality. The substitution of carboxyl group with methoxyl group was found to proceed with an inversion mechanism.

Journal Article↗
PubMed2000

Trigeminally induced cardiovascular reflex responses in spinalized rats.

The effects on cardiovascular functions of noxious stimulation to the orofacial areas innervated by trigeminal afferent nerves were analyzed in urethane-anesthetized, spinal cord-intact rats and in rats acutely spinalized at the second cervical level. In the spinal cord-intact rats, pinching of the upper lip produced increases in both heart rate (HR) and mean arterial pressure (MAP). Both responses were considered to be due to activation of sympathetic efferent nerves to the cardiovascular organs. Both responses were attenuated but did not disappear after spinalization at the C2 level. In spinalized rats, sympathetic preganglionic neurons emerging from the thoracolumbar spinal cord could not receive any neural influences from the brain. The HR response in the spinal rats was abolished after either bilateral vagotomy or intravenous injection of a peripherally acting muscarinic cholinergic receptor antagonist, methylatropine. This suggests that the increase in HR was elicited via vagal cholinergic efferent fibers, probably by decreasing tonic activity of vagus nerves to the heart. In spinal rats, neither vagotomy nor cholinergic blockade affected the increase in MAP, but i.v. injection of the vasopressin V1 receptor antagonist, OPC-21268, abolished the response of MAP. This suggests that the response of MAP was due to peripheral vasoconstriction elicited by vasopressin secreted from the posterior pituitary lobe. The present study demonstrated that, in rats acutely spinalized at the C2 level, noxious stimulation of orofacial areas innervated by the trigeminal nerve could produce reflex increases both in HR, by decreasing cholinergic vagal nerve activity to the heart, and blood pressure, by secreting vasopressin from the pituitary gland, even though sympathetic efferent innervation to the cardiovascular organs could not be directly affected by trigeminal afferent nerve excitation.

Animals↗
PubMed2000

Benign hyperthermia following prolonged TIVA with propofol.

PURPOSE: Propofol is widely used for general anesthesia because of its rapid onset and recovery. We had four cases that had higher body temperatures toward the end of anesthesia. The etiology of the hyperthermia is discussed. CLINICAL FEATURES: Four patients (three male, one female, 22-26 yr of age, weighing 53-57 kg) with facial deformities were anesthetized with propofol infusion (3-10 mg x kg(-1) x hr(-1)) and fentanyl (400-1,300 microg) without nitrous oxide, immobilized with vecuronium bromide (18-37 mg) or pancuronium bromide (31 mg). In order to reduce blood loss and improve the surgical view, tri-nitro-glycerin (TNG) was used in all cases. Osteotomy of maxilla and mandible or sagittal split ramus osteotomy of mandible was successfully performed. Although their body temperatures were normal preoperatively and stable during the operation, toward the end of anesthesia (one hour), they increased to over 38 degrees C. The room temperature was decreased and the water blanket on the operating table was also decreased. In addition, cool crystalloid solution was infused. Body temperature returned to normal in the ward and no complications due to the high temperature were seen postoperatively. It is thought that lighter anesthesia was masked by continuous infusion of propofol and TNG-induced hypotension and that benign hyperthermia occurred toward the end of anesthesia. CONCLUSION: Propofol reduces blood pressure, which suggests deep anesthesia. However, care must be taken to maintain the optimum depth of anesthesia during propofol anesthesia, especially when deliberate hypotensive anesthesia is induced.

Adult↗
PubMed2000

Morphological evaluation of the baboon hind limb muscles based on relative weight.

Morphological features of the hind limb muscles reflect the muscular function correlating with the locomotion. In this study, the muscles of the baboon hind limb were weighed and the relative muscle weights were compared with those of the human lower extremity. In the baboon, the biceps femoris was the largest (11.60%) and the vastus lateralis (10.67%) was placed second. The gluteus medius (8.55%) among the hip muscles and the gastrocnemius (4.38%) among the leg muscles were predominant in each segment. The relative weights of the gluteus medius and the biceps femoris were especially larger in the baboon than in the human, while the gluteus maximus and the soleus were larger in the human. The baboon gluteus medius and biceps femoris chiefly generate the propulsive power during quadrupedal locomotion and the human soleus is essential for the erect bipedalism.

Animals↗
PubMed2000

[Dental treatment for the handicapped by a combination of public community, dental association and university hospital--a system of Suginoki Dental Clinic].

Suginoki Dental Clinic, which is managed by Suginami Dental Association, financially supported by Suginami City, and technically assisted by the University Hospital, Tokyo Medical and Dental University, was established for dental treatment of handicapped persons living in Suginami City, Tokyo who are difficult to be treated by private practitioners. It has one full-time dentist, 12 part-time dentists, two dental hygienists, one nurse, and one clerk; one of the part-time dentists practices twice a week there. Since December 1994, 406 patients visited the clinic and the total cases was 9,273 in December 1999; 99 cases were mentally retarded, 36 autism, and 30 epileptic patients in the younger group; and 65 cases were cerebrovascular disease and 27 cardiac malfunction patients in the older group. Almost all the patients needed special care such as monitoring, intravenous sedation, nitrous oxide sedation, and general anesthesia. Four cases underwent general anesthesia, and no complication was seen among the cases. It was concluded that the clinic has been successful due to a good relationship among the Dental Association, Suginami City, and the dental hospital.

Community Dentistry↗
PubMed1998

Effects of propofol on a Ca2+-activated CI- current in rabbit ventricular myocytes.

Propofol is a widely used intravenous anesthetic, which is known to affect cardiac functions. Cardiac effects may be caused by direct actions on ion channels of the heart. While effects of propofol on several ion channels have been studied at the whole cell and single-channel levels, its effects, if any, on anion currents have yet to be examined. Effects of propofol on Ca2+-activated Cl- current (I(Cl(Ca))) were investigated in single myocytes isolated from rabbit ventricles by the whole-cell patch clamp technique at 36 degrees C. I(Cl(Ca)) was activated by perfusing internal solutions with 0.1 microM free Ca2+ in the absence and presence of 10 mM internal Na+, eliciting I(Ca)-dependent and -independent component, respectively. By the application of propofol (0.1-300 microM), I(Ca)-independent I(Cl(Ca)) was strongly inhibited in a dose-dependent manner with an IC50 of about 5 microM. The blocking effects of propofol were voltage independent. On the other hand, the I(Ca)-dependent component of I(Cl(Ca)) was little affected by propofol at concentrations of up to 50 microM. The outward Na+/Ca2+ exchanger current was also blocked by application of 5 microM propofol. We conclude that propofol inhibits cardiac I(Cl(Ca)) in rabbit ventricular myocytes, mainly the I(Ca)-independent component, at therapeutic concentrations. The inhibition may be due to block of a reverse mode of Na+/Ca2+ exchange current.

Action Potentials↗
PubMed1998

[Transient global amnesia after general anesthesia].

A 61 year old male patient with left mandibular cyst, received marsupialization of the left mandible under general anesthesia. Four hours after the end of anesthesia, his memory for the past 4 months and short term memory plastisity were impaired. No neurological abnormalies were found at that time. On the 2nd postoperative day, he recovered his lost memory for the past 4 months. The memory of events between 6 hours before operation and next morning, however, remained lost. It is suggested that the memory disorder is the TGA due to various causes including transient hypertension, operative stress, postoperative pain and diazepam.

Adjuvants, Anesthesia↗