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Biomedical subjects

M Sakaguchi

Publications and source records attributed to M Sakaguchi.

At least 469 records · Page 26Linked to original sources
PubMed1982

Effective treatment of the postoperative maxillary cyst by marsupialization.

The postoperative maxillary cyst occurs as a delayed complication after radical surgical intervention in the maxillary sinus. The recommended procedures for treating this entity have been enucleation followed by formation of an antronasal window, primary closure, or open packing. To prevent recurrence and unnecessary tissue destruction from surgery, marsupialization was performed in eight unilocular postoperative maxillary cysts. With the exception of a case in which the long-term results could not be obtained, the cysts disappeared in four months to two and a half years. Possible indications for marsupialization of the postoperative maxillary cyst are discussed.

Adult↗
PubMed1982

Potential radiosensitizing agents. 4. 2-Nitroimidazole nucleosides.

A series of 2-nitroimidazole nucleoside analogues has been synthesized as potential radiosensitizers in an effort to reduce neurotoxicity and increase therapeutic efficacy. The 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl and glucothiopyranosyl analogues of 2-nitroimidazole were synthesized by condensation in the presence of stannic chloride and mercuric cyanide. The deacetylation of these esters was carried out with sodium methoxide at 0 degree C. Condensation of the trimethylsilyl derivative of 2-nitroimidazole with methyl 2-deoxy-2-chloro-4,7,8,9-tetra-O-acetyl-N-acetyl-alpha-D-neuraminate was achieved in the presence of mercuric bromide. These agents were tested for cytotoxicity and radiosensitization in vitro against Chinese hamster (V-79) cells under oxic and hypoxic conditions. The thioglucose and sialic acid analogues were found to be active radiosensitizers.

Animals↗
PubMed1982

[Pharmacological studies on a prescription containing Bupleuri Radix (IV). Effects of saikosaponin on the anti-inflammatory action of glucocorticoid].

Effects of saikosaponin d extracted from Bupleuri Radix on the antigranulomatous action of glucocorticoid were investigated in rats by the cotton pellet method. Saikosaponin d (0.1 mg/kg/day x 4 days) and dexamethasone (0.1 mg/kg/day x 4 days) reduced the weight of cotton-induced granuloma to 89.58% and 88.54% of the control, respectively. These antigranulomatous actions failed to show a significant difference from the control. However, the combined administration of saikosaponin d and dexamethasone produced a significant antigranulomatous action, namely, the decrease in the weight of granuloma to 62.5% of the control. While the combination of saikosaponin d and dexamethasone showed an inhibitory trend against the increase in serum triglyceride as induced by dexamethasone, the cholesterol level was elevated by the combination. The body weight was significantly reduced by the combined administration as compared with the group treated with dexamethasone alone, but no apparent difference existed in the adrenal and thymus weights between them.

Animals↗
PubMed1981

Conduction velocity of peristaltic waves in the in vivo ureter: application of a new diameter gauge.

The conduction velocity of peristaltic movements of the canine ureter was measured under anaesthesia with a new type of diameter gauge using an image sensor. The peristaltic velocity was 34.1 +/- 6.2 mm/sec in 10 experiments. Noradrenaline at a low dosage of 1 microgram/kg i.v. reduced the resting diameter, increased the conduction velocity to 47--56 mm/sec, and approximately doubled the frequency of contraction. The application of acetylcholine also caused an increase in both frequency and conduction velocity (42--46 mm/sec). A plot of the conduction velocity against the mean period of peristaltic contraction was hyperbolic in shape.

Acetylcholine↗
PubMed1981

Erythrocyte membrane stabilization by plant saponins and sapogenins.

Effects of saponins extracted from Bupleuri Radix (saikosaponin) and the corresponding aglycones on hypotonic or hyperthermic hemolysis were investigated. Low concentrations of saikosaponins protect or stabilize rat erythrocytes against both hypotonic and heat-induced hemolysis. Minor modifications of the aglyconic part of the saikosaponin have enormous effects on the membrane stabilizing potency. Saikogenins also protect erythrocytes from hypotonic hemolysis but do not show any prevention of heat-induced hemolysis. It is suggested that saikogenins react with erythrocyte membranes in a quite different manner from saponins and that the existence of the sugar moiety plays an important role in the reaction with membranes as does a slight modification of the molecular structure in the aglyconic part.

Animals↗
PubMed1981

A comparative study on the rate of de-esterification of dexamethasone phosphate and dexamethasone sulfate in synovial fluids.

Considering the importance of the 21-OH group in promoting the anti-inflammatory activity of the steroids, it is possible that differences in the rate of hydrolysis of steroid esters may influence the potency of pharmacological activity of the steroids (Polley and Mason, 1950, Goldfien, et al., 1955). In the present paper the rate of de-esterification of the steroid esters in human synovial fluids was studied in vitro. Hydrolytic rates of dexamethasone-21-sulfate (DS) and dexamethasone-21-phosphate (DP) in synovial fluids aspirated from the knee joint of 10 patients each with rheumatoid arthritis and osteoarthritis of the knee measured by radioimmunoassay. DP was hydrolyzed to the extent of 10%, 30%, 50%, 80% after incubation for 1, 3, 6, 24 hours respectively. On the other hand, DS was hydrolyzed to the extent of less than 10% even after incubation for 24 hours. The difference between the rate of de-esterification of DP and DS for each period was statistically highly significant (p less than 0.001). These results suggest that DP is hydrolyzed in synovial fluids much faster than DS and converted into free dexamethasone which may exhibit a powerful anti-inflammatory action.

Arthritis, Rheumatoid↗
PubMed1981

Initiation of uterine contractions by purely mechanical stretching of the uterus at midpregnancy.

Purely mechanical stretching was applied to the uterus in normal midpregnancy by means of two No. 10 Nelaton catheters. Very gradual and steady onset of uterine contractions without hypertonia and hyperactivity were noted in all cases. All patients, in whom all possible afferent nerves of the uterus were blocked by continuous extradural and caudal anesthesia throughout the stretch treatment, also showed similar inauguration of uterine contractions. Uterine activity values indicated no significant difference between the nerve block and the non-nerve block groups (p = 0.68), but these values differed significantly with increasing time after stretching (p less than 0.001). All fetuses were delivered unaffected. The delivered placentas showed normal histologic integrity, and autoradiographic study proved the viability of the trophoblasts. It was concluded that the nerve and fetoplacental functions are probably not involved in the initiation of labor in this method.

Abortion, Legal↗
PubMed1980

A camera-type diameter gauge applicable to small blood and lymph vessels.

A camera-type diameter gauge was constructed and used in physiological experiments. The distinctive features of the design and use of the gauge may be summarized as follows. Installation of an image sensor in the focal plane of a single-lens reflex camera equipped with a set of extension tubes which makes it possible to measure outer diameters of blood and lymph vessels as small as 100 micrometer. Using the gauge, we can distinguish a diameter change of about 12 micrometer. Simultaneous measurements of the diameters of two different vessels can be made using two window signals generated independently at desired moments for appropriate periods within the video scans.

Animals↗
PubMed1980

An approach to the pathogenesis of "white finger" induced by vibratory stimulation: acute but sustained changes in vascular responsiveness of canine hindlimb to noradrenaline.

A fixed vibratory stimulation (60 Hz in frequency, 3 g in acceleration, and 2.2 mm in amplitude) was applied to a hindlimb (test limb) of dogs anaesthetised with sodium pentobarbital. Peripheral vascular resistance in the test limb was calculated as the ratio of mean pressure difference between the femoral artery and the femoral vein to the rate of femoral arterial blood flow. By means of a highly sensitive clinical thermometer, interdigital temperature was recorded not only from the test limb but also from a forelimb (control limb). The vibratory stimulation significantly reduced the peripheral resistance in the test limb. The increase in peripheral resistance induced by noradrenaline administration was suppressed during, and enhanced 1 h after, the stimulation. With the start of the vibratory stimulation, interdigital temperature in the test limb rose gradually and reached a constant level. The temperature first went below, and then returned to, the initial level after interruption of the stimulation. No change in the temperature was produced in the control limb. The decrease of temperature induced by noradrenaline administration was suppressed during, and enhanced 1 h after, the stimulation. These results indicate that, even in the living body, the conclusion of our previously report is valid: ie the responsiveness of arterial smooth muscle to noradrenaline decreases during, and increases soon after, vibratory stimulation. Assuming that our results obtained from acute experiments can be applicable to human digital arteries, the occurrence of "white fingers" on vibration disease may be understood in terms of vibration-induced hyperresponsiveness following stimulation.

Animals↗
PubMed1980

Active and passive mechanical characteristics of bovine mesenteric lymphatics.

Pressure-volume and pressure-radius relationships in lymphangions isolated from bovine mesenteric lymphatics were similar in pattern with those in the vein. Circumferential modulus of elasticity of the lymphatics ranged from 4.2 x 10(4) tatic walls. The contractile force increased in early stages of distension and decreased after an optimal intraluminal pressure was attained. The spontaneous activity was also affected by the rate of wall deformation. The pacemaker site of spontaneous activity seemed to be in the wall in the immediate vicinity of the inlet valve of a lymphangion. The activity propagated with a velocity of 4-5 mm/s. Ejection fraction of a lymphangion was between 45 and 65%. The endurance limit of the lymphatic valve was 68.4 +/- 7.6 cmH2O in specimens of about 3 mm in outer diameter. These findings suggested that lymphatic smooth muscle seemed to play a major role in elastic behavior of the wall and in regulation of the spontaneous activity, thereby affecting significantly passive and active lymph transport.

Animals↗