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Biomedical subjects

T Kawada

Publications and source records attributed to T Kawada.

At least 271 records · Page 15Linked to original sources
PubMed1989

[Effects of noise on sleep. Part 2. A case report of the effects of three levels of stationary sound on sleep parameters].

The effect of steady noise on sleep was examined experimentally for 24 nights by sleep polygraphy of a twenty-eight-year-old man. The parameters used for sleep polygraphy were sleep stage, sleep latency, frequency of sleep stage shift per hour, average sleep depth, the gradient and intercept of a regression line of sleep depth against time, and subjective sleep. The sleep stage was judged and estimated based on the criteria of Rechtschaffen & Kales by the authors' original system using a microcomputer. For the calculation of sleep depth at a given time, stages W (waking), 1, REM, 2, 3 and 4 were weighted to be 0, 1, 1.5, 2, 3 and 4, respectively. Sleep parameters were compared between the data of non-noise and noise-exposed nights. The noise exposure was overnight stationary pink noise of 40, 50 and 60 dB (A). General findings were a decreased REM stage, an increased stage 2, and deepened average sleep depth of the 60 dB (A)-night sleep compared with the control and 40 dB(A) exposure nights. When the control nights were excluded and parameters were compared between the three levels of stationary noise exposure, stage 2, the intercept of the regression line, and average sleep depth were increased almost in proportion to the increased noise exposure. In contrast, sleep latency, frequencies of sleep stage shift, stages W, 1, 3, MT, and REM, as well as the gradient of the regression line were decreased with increased noise exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Effects of noise on sleep. Part 3. A case report of the effects of three levels of intermittent sound on sleep parameters].

One healthy twenty-eight-year old man was exposed all night to intermittent, rectangular pink noise of 5 and 10 seconds' duration 9 times per hour. The peak levels prepared were 40, 50 and 60 dB(A). One level of the noise was exposed throughout a single night. Ten non-exposed control nights were also prepared. The sleep electroencephalogram was analysed by a microcomputer system of the authors' devising. Increases of sleep latency and stage W, and decreases of the REM stage and mean sleep depth, especially in the early sleep hours, were confirmed in the sleep polygraph of the 60 dB(A) exposure but not in that of the control, 40, and 50 dB(A) exposures. It was concluded from these results that the intermittent 60 dB(A) pink noise exposure clearly disturbed sleep, and that the threshold of the effect should exist between 50 and 60 dB(A) exposure.

Adult↗
PubMed1989

[Baseline study of sleep electroencephalography--daily variation and individual variation].

The aims of the present study were to observe the daily habituation to night sleep in a laboratory environment and to make clear the daily and individual sleep variations by using polygraph parameters, including electroencephalography (EEG). Sleep EEG records were obtained from a subject who slept ten successive nights, and from six subjects who each slept one night in the laboratory. The parameters used were as follows: sleep stage %, sleep latency (SL), REM latency (RL), number of stage shifts, subjective sleep, integral EMG, and slope (a) and intersect (b) of a regression equation used to estimate the sleep depth against sleep time. Stage WAKE and SL, slope (a), intersect (b) and the mean depth of sleep were found to become stable from the fifth night. Stage MT, the number of stage shifts, and integral EMG increased significantly from the fifth night and later, showing p less than 0.01, p less than 0.01, and p less than 0.05, respectively. Judging from these findings, the sleep habituation of the subject in the laboratory was completed within the first four nights. Coefficients of variation of sleep stage 2 and stage REM of the ten-nights' EEG were the lowest among all the sleep parameters examined. Almost all the parameters of day-to-day sleep of the subject who slept for ten successive nights in the laboratory showed smaller variations than those of the other six subjects. It may be concluded that the mist effect on sleep could be assessed more precisely by using an individual repeatedly than by using a group of subjects.

Adult↗
PubMed1989

Alkylated cAMP derivatives: selective synthesis and biological activities.

Many alkylated cAMPs have been prepared and tested for their antitumor and cardiac activities. Treatment of cAMP with several bases and alkyl bromides gave alkyltriesters of cAMP (2), N6,N6,2'-O-trialkyl cAMPs (3), N6,2'-O-dialkyl cAMPs (4) and 2'-O-monoalkyl cAMPs (5) in one step. N6,N6-dialkyl cAMPs (6) were prepared from 2'-O-tosyl cAMP by the similar alkylation, followed by detosylation. Synthesis of N6-monoalkyl cAMPs (7) was achieved by the reductive alkylation of cAMP with aldehydes in one step. Alkyl triesters of cAMP exhibited antitumor activities against P815 cells. N6-mono and N6,N6-dialkyl cAMPs showed significant cardiac activities.

Alkylation↗
PubMed1989

[Membrane glycoproteins of human platelets: structures, functions, and abnormalities in Glanzmann's thrombasthenia and Bernard-Soulier syndrome].

Platelet membrane glycoproteins, especially those of GP II b-III a complex and GP Ib-IX complex, serve as receptors for adhesive proteins including fibrinogen, von Willebrand factor and fibronectin, thus supporting cell-cell and cell-matrix interactions. Thrombasthenia (TA) and Bernard-Soulier syndrome (BSS) are inherited bleeding disorders in which these membrane glycoprotein complexes are defective. This paper deals with the recent advances in platelet membrane glycoprotein research, and the membrane glycoprotein abnormalities in TA and BSS platelets, which have been disclosed by the development of improved methods of analysis. Furthermore, a case of TA is reported in which flow cytometry using murine monoclonal antibody revealed 18% of the normal level of GP II b-III a complexes in her platelets. The platelets of this patient aggregated well by the addition of high concentrations of collagen (40 micrograms/ml). The results of this patient show the necessity of new criteria for the diagnosis of TA based on the quantification of the residual contents of GP II b-III a complexes in platelets in each patient.

Bernard-Soulier Syndrome↗
PubMed1989

Anticardiolipin antibodies by an enzyme-linked immunosorbent assay: fundamental studies on the conditions for antigen-application and specificity of the assay.

We have established an enzyme-linked immunosorbent assay (ELISA) for anticardiolipin antibodies (aCL) using standard sera obtained from the Rayne Institute, St. Thomas' Hospital (London, U.K.). In this study, we compared several fundamental requirements for the assay with the standard assay as a reference, such as conditions for antigen application and test samples using our patients' samples. In addition, the specificity of our assay and cross-reactivities of aCL were also evaluated. In the standard assay, the concentration of antigen was optimal in the range of 30-100 micrograms/ml. The antigen-coating temperature was optimal at 4 degrees C for 16 hours. The method based on rapid evaporation of CL-ethanol solution can be used instead of the standard method. On the other hand, there was no significant difference in the results between physical conditions of the antigen (CL-ethanol solution vs. CL-micelles), between washing solutions (saline vs. PBS containing 0.05% Tween-20) and between test samples (sera vs. plasma). The aCL activity in our patients' samples was almost completely inhibited by pre-incubation of sera with either CL or phospholipid reagent for activated partial thromboplastin time (APTT). Interestingly, the aCL activity of the lupus anticoagulant was negative, but aCL-positive samples were also absorbed by the reagent for APTT. No inhibition of the aCL activity, however, was observed when patients' sera were preincubated with ss-DNA.

Autoantibodies↗
PubMed1989

[The results of bypass with the BioPump in the surgery of traumatic rupture of the thoracic aorta without heparin].

In surgery of the traumatic rupture of descending thoracic aorta, external shunt without systemic heparinization is commonly employed to avoid the bleeding of other injured organs as well as the ischemic injury of spinal cord. However, it provides no means of controlling the flow. We employed the BioPump without heparinization in 2 cases of traumatic rupture of descending thoracic aorta and additional 2 cases of aneurysm of thoracic aorta. Significant platelet loss occurred immediately after operation, however, there was no postoperative evidence of the organ failures due to microembolization. Heparinless bypass with the BioPump is considered to be safe and simple as an adjunct means in surgery of the traumatic rupture of thoracic aorta.

Adolescent↗
PubMed1989

[Idiopathic retroperitoneal fibrosis: report of 4 cases].

We report 4 cases of idiopathic retroperitoneal fibrosis (IRF). Two cases were demonstrated by surgical biopsy, and in one of them ureterolysis was performed at the same time. After pathological diagnosis, these two patients were treated by steroid therapy. The other two patients were suspected to have acute renal failure due to IRF, and they were treated by nephrostomy or by double-J ureteral stent. In one of them retroperitoneal fibrous tissue had almost disappeared on CT examination. None of these 4 patients have had recurrence of IRF.

Acute Kidney Injury↗
PubMed1988

Simultaneous micro-determination of nicotinamide and its major metabolites, N1-methyl-2-pyridone-5-carboxamide and N1-methyl-4-pyridone-3-carboxamide, by high-performance liquid chromatography.

A simultaneous micro-determination of nicotinamide and its major metabolites, N1-methyl-2-pyridone-5-carboxamide (2-py) and N1-methyl-4-pyridone-3-carboxamide (4-py) by high-performance liquid chromatography is described. The method employs a 7-ODS-L (250 mm X 4.6 mm I.D., particle size 7 microns) column eluted with 10 mM potassium dihydrogenphosphate-acetonitrile (96:4, v/v; pH adjusted to 3.0 by the addition of concentrated phosphoric acid) at a flow-rate of 1.0 ml/min. The UV detector was set at 260 nm. The detection limits for nicotinamide, 2-py and 4-py were 10 pmol (1.22 ng), 2 pmol (304 pg) and 2 pmol (304 pg), respectively, at a signal-to-noise ratio 5:1. Isonicotinamide was used as an internal standard. The technique was applied to the analysis of rat and human urines. The total analysis time was ca. 15 min.

Animals↗
PubMed1988

Portopulmonary shunt by splenopneumopexy for portal hypertension in children.

Portopulmonary shunting by splenopneumopexy was successfully performed on seven children with portal hypertension, associated with extrahepatic portal vein occlusion in six and congenital hepatic fibrosis in one. Technically, this procedure is very simple and safely performed even in infancy. No operative mortality has been encountered to date. All children with portal hypertension treated by this portopulmonary shunt are doing very well, without any disturbances in their growth. Their postoperative survival ranges from 8 years and 9 months to 17 years and 9 months. Splenic pulp pressure was reduced to a postoperative mean value of 306 +/- 40.7 mmH2O from a preoperative mean value of 402.9 +/- 35.7 mmH2O. Hemorrhages esophageal varices were completely controlled postoperatively. Postoperative liver function tests were essentially unchanged from the preoperative values.

Child↗
PubMed1988

Adrenal sympathetic efferent nerve and catecholamine secretion excitation caused by capsaicin in rats.

Capsaicin enhances adrenal medullary catecholamine secretion. The participation of the central nervous system on this enhancement by capsaicin was investigated in alpha-chloralose-urethan- or halothane-anesthetized rats. Intravenous administration of capsaicin caused a rapid and marked increase in adrenal sympathetic nerve activity. The nerve activity began to show an increase with the administration of capsaicin at a dosage of 20 micrograms/kg and significantly increased with a dosage of 200 micrograms/kg, i.e., capsaicin was found to cause a dose-dependent increase in adrenal nerve activity. Cholinergic blocking with hexamethonium bromide and atropine sulfate (1 and 5 mg/kg iv, respectively) attenuated the adrenal epinephrine secretion caused by capsaicin. The direct action of capsaicin on adrenal catecholamine secretion was examined using a retrograde perfusion system of left adrenal gland. Up to 8.2 X 10(-5) M capsaicin did not enhance catecholamine secretion from the adrenal gland. These results suggest that the enhancement of physiological catecholamine secretion by capsaicin is mainly through activation of the central nervous system.

Adrenal Glands↗
PubMed1988

Effect of capsaicin pretreatment on capsaicin-induced catecholamine secretion from the adrenal medulla in rats.

The effect of capsaicin pretreatment on adrenal catecholamine secretion induced by intravenously administered capsaicin was investigated in alpha-chloralose and urethane anesthetized rats. In neonatal vehicle pretreated rats, capsaicin (200 micrograms/kg, iv) caused a rapid and significant increase in adrenal epinephrine secretion, but neonatal capsaicin pretreatment (50 mg/kg, sc, on the 2nd day of life) significantly reduced both the basal and capsaicin-induced epinephrine secretion from the adrenal medulla. Adult capsaicin pretreatment (6 increasing doses/6 days, total 310 mg/kg, sc) also reduced both the basal and capsaicin-stimulated adrenal epinephrine secretion, though it was less effective compared with the neonatal capsaicin pretreatment. These results suggest the participation of capsaicin-sensitive neurons in capsaicin-induced catecholamine secretion from the adrenal medulla.

Adrenal Medulla↗
PubMed1988

Some pungent principles of spices cause the adrenal medulla to secrete catecholamine in anesthetized rats.

We recently reported that capsaicin, a pungent principle of hot red pepper, evokes catecholamine secretion from the rat adrenal medulla. In this study, the effects of some pungent principles of spices on adrenal catecholamine secretion were investigated as compared with that of capsaicin. An increase in catecholamine, especially epinephrine, secretion was observed not only on capsaicin infusion but also on piperine (a pungent principle of pepper) and zingerone (ginger) infusion. Even on infusion of the same amount (650 nmol/kg, i.v.), the order of potency as to catecholamine secretion was capsaicin much greater than piperine greater than or equal to zingerone. While, sulfur-containing and volatile pungent principles, allylisothiocyanate (mustard, etc.) and diallyldisulfide (garlic, etc.), did not even cause slight catecholamine secretion. Furthermore, these adrenergic secretagogues were readily transported via the gut into the body. These results indicate that some pungent principles of dietary spices can induce a warming action via adrenal catecholamine secretion.

Adrenal Medulla↗