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Biomedical subjects

M Tsuruoka

Publications and source records attributed to M Tsuruoka.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Development of a new system for measuring the mean film thickness of the white silicone on the fitness test of the denture base].

A new system is developed for measuring the mean film thickness of the white silicone on the fitness test of the denture base. This system is based on analysing the B/W film density replaced from the thickness of the silicone. The detective feature of this system is as follows: 1. An adequate correlation between the logarithm of the thickness of the white silicone and the logarithm of the B/W film density was estimated from the results of experimental values. 2. With use of the computer assembled into the system, it is capable to quickly process data. 3. Compared with the conventional method, the proper suggestion was gotten to the clinical data. 4. The system is available to use of investigating the bite force and the mean film thickness of the white silicone.

Bite Force↗
PubMed1989

Physiological identification and property of afferents from the masseter muscle to the caudal part of the trigeminal nucleus in rat.

The present study was to identify the physiological properties of the afferent fibers from the masseter muscle to the caudal part of the spinal trigeminal nucleus of rat using a microelectrode technique. When electrical stimulation was applied to the masseter muscle, the evoked potentials were recorded with a shorter latency (the S-response) or a longer latency (the L-response). The threshold current intensity of the S-response was lower than that of the L-response. There were statistical significant differences between the S-response and the L-response in latency and in threshold current intensity. Both the S- and L-responses could follow by stimulation of low frequencies (10 to 30 Hz), indicating that the evoked responses were the component of the secondary neuron activities. On the anatomical and physiological assumption, the conduction velocities of the S- and the L-responses were calculated and they were in the range of that of A-delta fibers. We also observed that both the S- and the L-responses could not follow high frequency stimulation of the masseter muscle. This effect may reflect the phenomenon of fatigue in the finely myelinated fibers or polymodal nociceptors. Thus, the present study suggested the involvement of the afferents from the masseter muscle to the spinal trigeminal nucleus in the transmission and the relay of the masticatory muscle pain.

Afferent Pathways↗
PubMed1989

[An experimental study of the measuring system of the mean film thickness of white silicone through image analysis].

Clinically, the fitness test of a denture base employing white silicone has been widely used, and there are several methods for assessing the results. However, none of the conventional methods of assessment are completely objective or quantitative. For solving these problems, a new system has been developed for measuring the mean film thickness of white silicone based on image analyzing. There are several factors that affect the results of the fitness test of the denture base, such as the shape of the denture, the condition of the mucosa within denture bearing area, bite force and the state of occlusal contact. Then, using the new system, these factors were examined for clinical application of the mean film thickness of white silicone. The experiments are composed of three stages. In the first stage, the white silicone was pressurized between two of tablets involved in three types, with a pressurizer. These data resulted in a regression equation applying the rheological equation. In the second stage, pressurizing tests were performed on the models of jaw mucosa with uniform compressibility. The models were categorized into three types according to their compressibility. A result was the more compressible the models of jaw mucosa are, the thicker the white silicone film is. In the third stage, the compressibilities were mixed in the models of jaw mucosa. In the pressurizing test, the compressing dies were modeled on the denture base. Five loading points were established on the surface. Correlation between data obtained from the results of the pressurizing test at each loading point was investigated. The results from these experiments were as follows. 1. The regression equation was established from the compressing test of white silicone between tablets of rigid type. H = 0.236 (r1r2/square root of P) -0.0008 R = 0.977 H: mean film thickness of white silicone R: coefficient of correlation P: loading volume r1: 1/2 of the major side of the each tablet r2: 1/2 of the minor side of the each tablet Units are expressed in the C. G. S system. The film thickness was more highly correlated with the distance to the open system of each tablet than the area.

Denture Bases↗
PubMed1988

Quantitative relationship between the stimulus intensity and the response magnitude in the tail flick reflex.

The purpose of the present study was to investigate the quantitative relation between the stimulus intensity and the response magnitude of the tail flick reflex. The EMG of a tail muscle was recorded from the extensor caudae medialis (ECM) muscle in the side contralateral to heat stimulation, and the area of integrated EMG for 1 sec was measured as the magnitude of EMG activity. The minimum temperature to the onset of the EMG was 42.3 +/- 0.4 degrees C. The relation between the stimulus intensity and the magnitude of an integrated EMG followed a power function with an exponent of about 8.5. The magnitude of an integrated EMG was decreased by about 50% of the control by an intraperitoneal administration of morphine (0.5 mg/kg). These results suggest that tail flick reflex is closely related to painful sensation, and that EMG activity of the ECM muscle is applicable as an electrophysiological indicator to noxious stimulation of the tail and an expressible indicator of the magnitude of pain.

Animals↗
PubMed1988

Three cases of delivery under sodium valproate--placental transfer, milk transfer and probable teratogenicity of sodium valproate.

Here is a report of three cases of delivery from women who have taken sodium valproate (VPA). One neonate was born with polydactylism, and we reviewed the congenital malformations in children of mothers who have taken VPA. In the other two cases, we also examined the levels of VPA in the cord serum and breast milk. The levels of VPA in the cord serum were 50 micrograms/ml at 12 hours after the last maternal dose and 75 micrograms/ml at 14 hours after the last maternal dose. The blood levels of VPA in the two mothers were 48-59 micrograms/ml and 55-85 micrograms/ml in their late pregnancy, respectively. The levels of VPA in the breast milk were 2.0-3.5 micrograms/ml and the ratio of VPA in the breast milk to blood was 2-3%. These results suggest the high rate of placental transfer and the low rate of milk transfer of VPA.

Abnormalities, Drug-Induced↗
PubMed1988

[The expression of c-myc, c-fms, c-sis oncogenes in the trophoblast of normal pregnancy and trophoblastic disease].

Recently it has been suggested that proto-oncogene plays a role not only in cellular proliferation, development and differentiation, but also in neoplastic transformation. We now show the expression and its localization of c-myc, c-fms and c-sis proto-oncogenes in human developing chorionic tissue and fresh surgical specimens of mole and choriocarcinoma with the method of Northern blotting and In-situ hybridization. The 2.4kb c-myc transcript has been localized to the cytotrophoblast in early placenta and also localized to the C and S typed trophoblastic cells in mole and choriocarcinoma. The 4.0kb c-fms transcript has been localized to the syncytiotrophoblast, especially the highly differentiated syncytiotrophoblast in the second and third trimesters and S typed trophoblastic cells in mole and choriocarcinoma. Moreover, the 4.0kb c-sis transcript has been localized to the cytotrophoblast in early placenta, but not detected in mole or choriocarcinoma. First, these results suggest that the stage and site specific expression of c-myc, c-fms and c-sis proto-oncogenes are clearly related to the proliferation, development and differentiation of normal trophoblastic cells. Second, the expression of c-myc, c-fms proto-oncogenes may be of particular importance in the tumorigenesis and progression of trophoblastic disease.

Blotting, Northern↗
PubMed1987

Suppression of the tail flick reflex by electroacupuncture delivered at the intra- and extrasegmental needling points.

Electroacupuncture effects conveyed by A beta afferent nerve impulses from the different dermatomes, the Zusanli and the Hoku, was compared using the tail flick reflex in lightly anesthetized rats. The Zusanli stimulation decreased the EMG activity, but the threshold temperature did not change. These effects were not antagonized by naloxone (1 mg/kg). The Hoku stimulation also produced the suppression of the EMG activity without the increase of the threshold temperature. However, these effects were antagonized by naloxone (1 mg/kg). These results suggest that intrasegmental stimulation presynaptically inhibits the input of the noxious message in the spinal cord through the non-opiate system, while extrasegmental stimulation presynaptically inhibits this input through the opiate system.

Acupuncture Therapy↗
PubMed1987

[The prevention of CDDP-induced emesis with a combination regimen including metoclopramide, dexamethasone, droperidol and diphenhydramine].

The dose limiting factors of cisplatinum are nephrotoxicity and emesis. Nephrotoxicity has been reduced by hydration but nausea and vomiting caused by cisplatinum have led to refusal of potentially curative therapy by a number of patients. The prevention of nausea and vomiting by a combination of antiemetic drugs administered to ovarian patients receiving chemotherapy inducing (cisplatinum 50mg/m2, adriamycin 300 mg/m2, cyclophosphamide 300 mg/m2 and 5FU 350 mg/m2) was studied. the combination antiemetic drugs were metoclopramide (1mg/kg), dexamethasone (10mg/m2), droperidol (1mg/m2) and diphenhydramine (20mg/body). These drugs without diphenhydramine were administered intravenously 30 minutes before and 2.5 hours, 5 hours and 7.5 hours after chemotherapy. Diphenhydramine was administered intramuscularly 30 minutes before and 5 hours after chemotherapy. No vomiting was noted in 82.6% (19/23) of cases, and no patient vomited more than four times. This combination regimen provided very good protection against cisplatinum induced emesis.

Adult↗
PubMed1983

Improvement of the oral bioavailability of digitalis glycosides by cyclodextrin complexation.

Inclusion complexes of the digitalis glycosides digitoxin, digoxin, and methyl digoxin with three cyclodextrins (alpha-, beta-, gamma-homologues) in water and in the solid state were studied by a solubility method, IR and 1H-NMR spectroscopy, and X-ray diffractometry. Solid complexes (in a molar ratio of 1:4) of the digitalis glycosides with gamma-cyclodextrin were prepared and their in vivo absorption examined. The rapidly dissolving form of the gamma-cyclodextrin complex significantly increased plasma levels of digoxin (approximately 5.4-fold) after oral administration to dogs.

Animals↗
PubMed1982

Induction of choline kinase by polycyclic aromatic hydrocarbons in rat liver. II. Its relation to net phosphatidylcholine biosynthesis.

The effect of a single dose (50 mg/kg body weight) of 3-methylcholanthrene on de novo phosphatidylcholine biosynthetic activities in rat liver was studied both in a cell-free system and with slice experiments. 3-Methylcholanthrene caused a significant depression of either [methyl-14C]choline or [2-(3)H]glycerol incorporation into phosphatidylcholine when the precursor was incubated with liver slices. At the same time, there occurred a significant accumulation of radioactivity in either cholinephosphate or diacylglycerol molecule from [14C]choline or [3H]glycerol, respectively, suggesting that 3-methylcholanthrene could cause an inhibitory effect on hepatic phosphatidylcholine synthesis at the cholinephosphotransferase or/and cholinephosphate cytidylyltransferase step. Subsequent studies, where the activities of the three enzymes involved in de novo phosphatidylcholine synthesis were compared between control and 3-methylcholanthrene-pretreated rat liver subcellular fractions, demonstrated that the cholinephosphotransferase step could be the site of inhibition by 3-methylcholanthrene. On the other hand, 3-methylcholanthrene caused a significant induction of choline kinase activity in a time-dependent manner and, at the same time, the cholinephosphate pool size in liver cytosol was enlarged 2-3-fold when compared to the respective control. The overall results suggested strongly that 3-methylcholanthrene causes the counteractive effects on the de novo phosphatidylcholine biosynthesis, induction of choline kinase activity and inhibition of cholinephosphotransferase activity, both of which could participate in a concomitant increase in cholinephosphate pool size in rat liver.

Animals↗