Biomedical subjects

T Kumazawa

Publications and source records attributed to T Kumazawa.

At least 289 records · Page 16Linked to original sources

PubMed1990

Functions of the nociceptive primary neurons.

The functions of nociceptive primary neurons are reviewed in brief, with special reference to the polymodal receptor. The polymodal receptor is considered to be a primitive sensory receptor that is not well differentiated and that plays important roles in signaling pain especially from tissues in pathological states, and in causing reflex modulations of a wide variety of bodily functions. This sensory receptor is characterized by the existence of neuropeptides in its neuron. The wide distribution of the central axon branchings of this neuron and the long-lasting effects of the neuropeptides released from the axon terminals provide an "analogue-like" action of the nervous system, which had hitherto been considered to be "digital-like," point-to-point connections in the central neuron network. Neuropeptides released from the peripheral endings of this neuron, on the other hand, play important roles in local regulation of such functions as inflammation, visceral tract motility, trophic effects, immune system functioning and so on. The functions of nociceptive primary neurons are, therefore, not limited to sensory function but should be understood as a component related to the regulation of fundamental functions of the entire organism.

Afferent Pathways↗

PubMed1990

Augmentation of muscle nociceptive respiratory reflex facilitation by vagal afferents.

Vagal influence on the facilitation of phrenic neural activity during respiratory phase-locked, gastrocnemius muscle nerve nociceptive electrical stimulation was examined in anesthetized, glomectomized, paralyzed, and artificially ventilated cats. (1) In the vagi-intact state, respiratory reflex facilitation was characterized by a sharp rise in peak amplitude, maximum rate of rise or slope, and mean rate of rise of integrated phrenic nerve activity. This was greater during inspiratory phase-locked (T1-locked) muscle nerve electrical stimulation than during expiratory phase-locked (TE-locked) muscle nerve electrical stimulation. "Evoked post-inspiratory phrenic activity" during the early expiratory phase was also observed during TE-locked muscle nerve electrical stimulation. (2) Bilateral vagotomy significantly attenuated the respiratory facilitation during both T1- and TE-locked muscle nerve electrical stimulation. In particular, the "evoked post-inspiratory phrenic activity" during TE-locked muscle nerve electrical stimulation was also attenuated or almost completely abolished. (3) Conditioning electrical stimulation of the vagus nerve revealed facilitatory reflexes which co-exist with inspiratory inhibitory reflexes. (4) The "evoked post-inspiratory phrenic activity" during TE-locked muscle nerve electrical stimulation, which was attenuated or abolished after vagotomy, was restored after vagal T1-locked conditioning stimuli combined with TE-locked muscle nerve electrical stimulation. The results suggest that vagal facilitatory reflexes augment the respiratory reflex facilitation during muscle nociceptive stimulation.

Afferent Pathways↗

PubMed1990

The tonsillar immune system: its response to exogenous antigens.

The palatine tonsil is the only lymphoid organ directly exposed to the outside environment. This characteristic anatomical feature appears to be immunologically significant with the defence activity primarily directed against exogenous antigens. However, the palatine tonsil is also often the site of secondary diseases, such as focal infections. This study investigated how the tonsil responds to horseradish peroxidase (HRP) dropped into the crypts and the effects of this response on the regional lymph node and the kidney as a distant organ. HRP entered through the microcrypts was phagocytosed by macrophages, gathered mostly around the vessels and emigrated to the regional lymph nodes. Anti-HRP antibody-producing cells were observed not only in the tonsil but also in the regional lymph node. In this long-term study with repeated immunization, fusion of the epithelial foot process and reduction of the anionic charge in the glomerulus were often found electron microscopically. This investigation suggests that the tonsil has important roles in the defence activity in relation to the general immune system; otherwise it becomes a primary site for focal infections.

Animals↗

PubMed1990

New findings in observations by tubo-tympano-aerodynamic method.

We studied Eustachian tube function of healthy adults by two air flow methods, namely tubo-tympano-aerodynamic graphy by Valsalva maneuvre, and Tyonbee maneuvre during swallowing. We observed for the first time the presence of reciprocal features in normal Eustachian tubes. We also compared the tubal function of the same group using an air flow method and sound transmission method. The results of these observations showed that 77.4% of the subjects were positive for TTAG in Valsalva pattern, and 85.4% for sonometry. It can be inferred that data on the tubal opening in response to Valsalva and Toynbee maneuvres is obtained more easily by sonometry than by TTAG. TTAG, which permits examination of minute changes in air flow dynamics even in healthy Eustachian tubes, provides more important information on tubal function than does sonotubometry.

Adolescent↗

PubMed1990

Middle ear ventilation mechanism.

The ventilation mechanism of the middle ear is very important as regards the pathogenesis of middle ear disease, but its mode of function is still obscure. Therefore, we tried to measure the ventilation and clearance of the middle ear using radio-isotope imaging techniques and 133Xe in order to gain a clearer picture of the ventilation mechanism. In normal Eustachian tube cases, approximately 10% of the initially insufflated gas immediately entered into the middle ear cavity and mastoid air cells. The gas introduced into the middle ear diminished at a rate of 8% of volume per hour in the normal resting state. Two hours after the first procedure, air was insufflated, and gas volume in the middle ear cavity immediately diminished by 30%. In stenotic tube cases, it proved difficult to insufflate the gas into the middle ear, however, its diminishing rate with the passage of time was slightly faster than in normal tube cases. From this data, it was evident that air could easily and quickly enter into even the periphery of the mastoid air cells by insufflation via the Eustachian tube, despite the fact that the middle ear and mastoid air cells form a closed cavity. In the resting state, moreover, the air in the middle ear was thought to be absorbed mainly into the middle ear mucosa at a regular rate. It was confirmed that the insufflation procedure as a therapy for tubal stenosis and OME is very useful for the ventilation of the middle ear.

Air↗

PubMed1990

Implication of polymodal receptor activities in intraocular pressure elevation by neurogenic inflammation.

We studied, using anesthetized albino rabbits, whether polymodal receptors are responsible for rise in the intraocular pressure (IOP) caused by algesic substances, and also whether substance P (SP) is involved in this phenomenon. Intracameral administration of bradykinin (BK), SP, hypertonic saline, and hypertonic glucose caused an IOP rise. The IOP responses to BK and hypertonic saline were reduced by benoxinate, but aspirin reduced only the response to BK. Repeated applications of BK caused a decrease in subsequent responses (tachyphylaxis). These results are consistent with the characteristics of responses of polymodal receptors, and suggest that these IOP responses are produced by neurogenic inflammation. The IOP response to SP also showed tachyphylaxis, but after the tachyphylaxis to SP had been established, subsequent intracameral administration of BK still produced a marked rise in IOP. Moreover, the administration of SP into the posterior chamber, which is known to be the site of the blood-aqueous barrier, caused a much smaller rise in the IOP. These observations indicate that the IOP response to algesic substances might be caused by activation of the polymodal receptors, and that SP might not be a mediator in these responses.

Animals↗

PubMed1990

Rapid isolation of some antiepileptic hydantoins and their analogues with Sep-Pak C18 cartridges and capillary gas chromatography with splitless injection.

A simple and rapid method for isolation of seven antiepileptics (2 hydantoin, 2 oxazolidin, and 3 suximide derivatives) from urine and plasma is presented. Urine and plasma (1 ml) samples containing seven antiepileptics were mixed with distilled water (4 ml), and the sample solution was poured into a pretreated Sep-Pak C18 cartridge; this was washed with water and chloroform/methanol was passed through it to elute the antiepileptics. The eluate was mixed with isoamyl acetate and evaporated under a stream of N2. The drugs were detected by gas chromatography with fused silica capillary columns, splitless injection and flame ionization detection. Separation of the seven antiepileptics from each other and from impurities was satisfactory with the use of an SPB-1 capillary column. The detection limit for the seven antiepileptics with the present method was 0.1-1.0 microgram/ml urine or plasma. The recovery of the drugs from urine and plasma was more than 70% and 50%, respectively.

Anticonvulsants↗

PubMed1990

[Epidural anesthesia with high dose fentanyl for abdominal surgery].

An epidural catheter was inserted at T9-L2 interspace and 10 micrograms.kg-1 fentanyl with (E+) or without (E-) epinephrine 1:100,000 was given for 82 elective abdominal surgeries. N2O 66%, enflurane and muscle relaxant were used as needed. The onset and the duration of the action were estimated to be approximately 15 minutes and 4 hours, respectively. Anesthesia was maintained with enflurane below 0.4% (0.22 +/- 0.09%) in 70 patients (85.4%). E+ group needed significantly lower concentration of enflurane than E- group. There was no severe hemodynamic change during the operation. Systolic pressure, diastolic pressure and heart rate during the operation were 115.2 +/- 16.0 mmHg, 69.4 +/- 10.8 mmHg and 74.2 +/- 11.4 min-1, respectively, each of which was about 18% less than the values on arrival in the operating room. Sixty-one patients (82.5%) woke rapidly. Almost all patients felt well and had no pain during the recovery period. Naloxone 0.05-4 mg was administered intravenously in 21 patients (31.7%) whose respiratory rate was below 10 min-1. The patients with shorter operation time (shorter than 2.5 hours) needed more naloxone. Troubles of respiratory depression did not occur in the recovery room and in the ward in both naloxone and non-naloxone groups. This anesthesia method which induces mild depression of blood pressure and heart rate may be indicated for patients with ischemic heart disease or with poor cardiac function, but has no advantages in patients with poor respiratory function who need early extubation after a short operation.

Abdomen↗

PubMed1990

[Repeated inadvertent subdural catheterization: a case report].

We had a patient who had repeated inadvertent subdural catheterization. Eighty-two year old woman with post herpetic neuralgia had a continuous epidural anesthesia for the relief of pain. An epidural catheter was inserted at the Th 5-6 interspace using a paramedian approach. Fifteen minutes after 4 ml test dose of 1% lidocaine injection, she developed circulatory depressions and massive sensory block. The exact position of the catheter and the distribution of the local anesthetic agent were confirmed by radiographic contrast material. The catheter was observed in the subdural space. Anesthesia was therefore continued with an injection of 1.5 ml mepivacaine. After one month, epidural catheterization was done in the same patient. The catheter was inserted in subdural space again. The subdural injection has been implicated in a case in whom there has been extensive spread of an epidural block. The diagnosis of subdural block can be made by a subsequent injection of contrast medium, since an unusual clinical course might be seen. Subdural space has a poor blood supply, and injected medium may stay in this space for considerable period of time. Subdural catheterization in epidural anesthesia probably occurs more frequently than previously recognized.

Aged↗

PubMed1989

Facilitatory effects of opioids on the discharges of visceral nociceptors.

Effects of opioids on the activity of visceral nociceptors were tested using the in vitro testis-spermatic nerve preparations excised from deeply anesthetized dogs. Morphine, DADLE and dynorphin (10 microM) elicited discharges of polymodal receptors in approximately 1/3 of the tested cases. The incidence of the excitatory response of morphine increased at higher concentrations. The excitatory responses were quite variable among preparations and showed a strong tendency for tachyphylaxis. Similar increases in discharges were elicited when morphine was applied during the steady state of the response evoked by bradykinin (BK) or BK mixed with prostaglandin E2. Pretreatment of morphine for 5 min significantly augmented the subsequent BK responses for 30 min or more. Naloxone per se induced neither excitation nor augmentation of the subsequent BK response, however it reversed the augmenting effect of morphine on BK response. In contrast with previous reports proposing peripheral analgesic effects of opioids, suppressive effects on nociceptors were never observed in the present experiment. Peripheral effects of opioids were discussed.

Animals↗

PubMed1989

Effects of sevoflurane with or without nitrous oxide on cardiac contractility and sinoatrial node rate.

Cardiac effects of sevoflurane (SE) with or without nitrous oxide were examined in the canine blood-perfused papillary muscle and sinoatrial node preparations. Although SE depressed developed tension (DT), mean arterial pressure (MAP) and heart rate of the donor dog (DHR) dose dependently, sinoatrial rate (SAR) was not changed significantly. No significant changes in MAP, DHR and SAR were observed with the addition of nitrous oxide to SE. However, the addition of nitrous oxide to SE resulted in significant decrease of DT. These results suggest that SE depresses BP and cardiac contractility dose dependently, but dose not change heart rate. The combination of nitrous oxide and SE may produce less cardiovascular depressant effect at a given MAC level than SE given alone.

Journal Article↗

PubMed1989

Increased P-glycoprotein expression and multidrug-resistant gene (mdr1) amplification are infrequently found in fresh acute leukemia cells. Sequential analysis of 15 cases at initial presentation and relapsed stage.

Using a DNA probe of mdr1 and an anti-P-glycoprotein monoclonal antibody (MRK16), the authors investigated 19 cases of adult acute leukemia patients (one M1, six M2, three M3, one M4, three M5, two L1, and three L2), comparing leukemia cells at the initial presentation (I) with those at the relapsed stage (R). By Southern hybridization analysis mdr1 DNA levels were not amplified in 32 samples from 19 patients (I: 14, R: 18). By Northern hybridization analysis mdr1 mRNA levels were not expressed in ten samples from seven patients (I: 4, R: 6). By indirect immunofluorescent assay with MRK16 antibody P-glycoprotein was not detected in 30 samples from 18 patients (I: 13, R: 17). Thus, P-glycoprotein expression and mdr1 gene amplification occurred infrequently not only in leukemia cells at the initial presentation but also in those at the relapsed cases and may not be a major cause of refractoriness to antileukemia drugs in adult acute leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1989

Effects of sevoflurane on myocardial metabolism during postischemic reperfusion in the rat.

In experiments on isolated rat heart lung preparation, the effects of sevoflurane on myocardial metabolism during postischemic reperfusion were evaluated with intramyocardial high energy phosphates, lactate and glycogen. Hearts were perfused for 10 min initially and made globally ischemic for 8 min. Afterwards, they were reperfused for 12 min. Sevoflurane was administered from 5 min after the start of perfusion to the end of reperfusion. There was no significant difference in myocardial lactate levels between the sevoflurane (S) and control groups. However, the myocardial ATP level in Group S was significantly higher than that in control (17.45 +/- 1.51 vs 15.50 +/- 0.87 : P < 0.01). The administration of sevoflurane to the isolated rat heart during pre- and post-ischemia enhanced metabolic recovery in the postischemic state.

Journal Article↗

PubMed1989

Ontogeny of calcitonin gene-related peptide in the organ of Corti of the rat.

The ontogeny of calcitonin gene-related peptide (CGRP)-like immunoreactive (CGRPI) fibers in the rat cochlea was examined using immunocytochemistry. It was found that the CGRPI cochlear system developed markedly in the postnatal period; CGRPI fibers first appeared in the inner spiral bundle at postnatal day 8, then at the base of the outer hair cells, tunnel spiral bundle and tunnel radial fibers at postnatal day 19. The ontogenetical profile elucidated by this study suggests that CGRP has a role as a neuromodulator or neurotransmitter in this system.

Animals↗

PubMed1989

Rapid isolation with Sep-Pak C18 cartridges and wide-bore capillary gas chromatography of some butyrophenones.

A simple and rapid method for isolation of five butyrophenones with Sep-Pak C18 cartridges from human samples, and their wide-bore capillary gas chromatography (GC), are presented. The GC was made by both flame ionization and electron capture detections. The drugs contained in alkaline samples were directly applied to the cartridges and eluted with chloroform/isopropanol (9:1). The recoveries with use of the cartridges were excellent for most drugs in both urine and plasma samples. We can recommend the Sep-Pak C18 cartridges for isolation of butyrophenones because of simplicity and rapidity, and also wide-bore capillary GC because of high sensitivity and low decomposition of drugs during passage through the column.

Antipsychotic Agents↗

PubMed1989

Clinical evaluation for the mechanism of cisplatin with bromodeoxyuridine by flow cytometry and clinico-histological study.

The tumor cell kinetics before and after intra-arterial injection of cisplatin (CDDP) was examined in a patient with maxillary carcinoma using flow cytometry and propidium iodide and fluorescein isothiocyanate labeled bromodeoxyuridine double staining. In addition, the viability was determined with fluorescein diacetate and compared with the histological picture. The action mechanism which the authors obtained 24 hours after intra-arterial injection of CDDP to the clinical case was considered to be S phase block, especially early S phase block. Markedly decreased viability also makes us consider the cytocidal effect. These findings correlated with the data of the fundamental investigation reported previously. Histological examination after the intra-arterial injection of CDDP revealed remarkable necrosis in the tissue.

Bromodeoxyuridine↗

PubMed1989

Effects of naloxone on cardiac energy metabolism in hypovolemic shock in rats.

It has been reported that naloxone may be useful in the treatment of hypovolemic shock. However, the effects of naloxone on cardiac energy metabolism in hemorrhagic shock have not been investigated. The effects of naloxone on myocardial metabolism were evaluated in the rats which were bled to a systolic pressure of 40 mmHg and maintained at that pressure for 30 min. Naloxone (10 mg/kg) was administered intravenously 5 min before the heart was removed. Then the intramyocardial high energy phosphates, pyruvate, lactate, and glycogen were measured. Naloxone increased systolic blood pressure and decreased heart rate significantly. However, there were no significant differences in high energy phosphates, energy charge, pyruvate, lactate and glycogen between the control and naloxone groups. These data suggest that naloxone may have no direct effect on the cardiac energy metabolism in a 30-min hypovolemic shock.

Animals↗

PubMed1989

Semicarbazide-sensitive amine oxidase activity in catfish tissues.

1. Semicarbazide-sensitive amine oxidase activity was found in five tissues of the siluroid catfish, Parasilurus asotus, using benzylamine as substrate. It was highest in the intestine, followed by the liver and skin. 2. The apparent Km value and optimal pH for benzylamine in the intestine were 49.8 microns and 8.8, respectively. 3. Substrate specificity of the enzyme was tested in the intestine and the highest activity was found with beta-phenylethylamine, followed by tryptamine and benzylamine.

Amine Oxidase (Copper-Containing)↗