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Biomedical subjects

M Higuchi

Publications and source records attributed to M Higuchi.

At least 415 records · Page 23Linked to original sources
PubMed1982

Age-related changes in the nucleus pulposus of intervertebral disc in mice. An electronmicroscopic study.

The nucleus pulposus of the intervertebral discs in mice from newborn to four months of age was examined by electron microscopy. The nucleus pulposus was packed with the cells which were distended with large vacuoles and aggregations of glycogen particles. These cells contained many filaments and poorly developed organelles. Numerous pinocytotic vesicles were present along the cell surface. Neighboring cells were connected with desmosomes. Thus, the cells composing the nucleus pulposus were similar to notochordal cells. The intercellular space contained granular substances as seen in the matrix of the cartilage. In the peripheral region of the nucleus pulposus, the cells relatively rich in organelles were occasionally observed. At two months or more of age, vacuoles of the cells of the nucleus pulposus became larger and more numerous, and the scanty cytoplasm contained fewer organelles but well-developed filaments. However, many pinocytotic vesicles could be still observed along the cell surface. Degenerated cells appeared.

Age Factors↗
PubMed1982

[Studies on neurobehavioral response (Scanlon test) in newborns after epidural anesthesia with various anesthetic agents for cesarean section].

In order to examine the influence of larger doses of anesthetic drugs on newborns, 146 infants delivered by cesarean section with epidural anesthesia employing various anesthetic agents were assessed by Apgar score, blood gas analysis, drug concentration as well as Scanlon's examination. The following results were obtained: 1. The fetal/maternal concentration ratio for bupivacaine was lowest compared with those of lidocaine and mepivacaine. 2. There was no significant difference among the epidural anesthesia with four kinds of anesthetic agents and spinal anesthesia groups in pH, Pco2, Po2 values or Apgar scores obtained from blood from the maternal artery or the umbilical vein. 3. The groups whose mothers had received epidural block with either lidocaine or mepivacaine for cesarean section showed significantly lower scores in Scanlon test compared with the groups with bupivacaine or chloroprocaine and spinal anesthesia group. From these findings, it may be concluded that bupivacaine or chloroprocaine does offer some advantages over (three local anesthetic agents) lidocaine, mepivacaine or tetracaine to the obstetric patients who need cesarean section for delivery.

Anesthesia, Epidural↗
PubMed1981

Transmural distribution of myocardial high energy phosphates and lactate in relation to the epicardial ECG in the underperfused canine heart.

The influence of coronary perfusion pressure (CPP) on the transmural distribution of myocardial metabolites was examined in the canine heart. Myocardial contents of high energy phosphates and lactate were measured in the inner, middle and outer third of transmural biopsies taken from the underperfused area of the left ventricle; simultaneously epicardial ECG was recorded. Maximum autoregulation of flow was reached when CPP was decreased by approximately 50%; this was indicated by the absence of reactive hyperemia. At this level, high energy phosphate and lactate contents as well as hemodynamic function remained relatively unaltered. At 40% of CPP, coronary flow and the high energy phosphate contents decreased significantly, especially in the subendocardium. At 30% of CPP, there was an accumulation of lactate and a decrease in creatine phosphate content to below one-third of the control in all layers; under these conditions also the ST-segment of the epicardial ECG was elevated. The ST-segment appeared to be relatively insensitive to subendocardial damage; instead, elevation of the ST-segment seemed to be correlated wit the content of lactate in the subepicardium.

Adenosine Triphosphate↗
PubMed1981

Participation of coronary perfusion pressure in transmural energy metabolism in the hypoperfused canine heart.

The participation of coronary perfusion pressure in hemodynamic and transmural metabolic changes was examined in the open chest canine heart. At lower pressure than 50% of the control, reactive hyperemia disappeared and the coronary arterial inflow precipitously decreased. In 8 dogs, when the coronary arterial inflow was decreased to 47-49% of the control by coronary constriction for 15 min, the coronary perfusion pressure fell in various degrees ranging from 39 to 73% of the control. At a lower pressure than 60% of the control, creatine phosphate (CP) content and its ratio of subendocardium (ENDO) to subepicardium (EPI) decreased, while lactate (LA) content and its ratio of ENDO to EPI increased depending on the degree of the fall in coronary perfusion pressure. A little decrease in ATP content was produced only in the subendocardium under the lower pressure than 50% of the control. When the CP content decreased to below one-third of the control, the significant accumulation of lactate and the precipitous decrease in ATP occurred. Our results suggest that the coronary perfusion pressure has an important role for a severity of the transmural energy metabolism in the hypoperfused ventricle.

Animals↗
PubMed1981

The thromboplastic activity of lung surfactant in amniotic fluid and its application to prenatal assessment of fetal lung maturity.

Based on the fact that both tissue thromboplastin and lung surfactant show lamellar structures under the electron microscope and belong chemically to lipoprotein, the thromboplastic activity of lung surfactant in amniotic fluid was studied by measuring plasma recalcification time. The results obtained were as follows (1) The surfactant fractions isolated from amniotic fluid and rabbit or pig lung showed the thromboplastic activity with dose response. (2) The thromboplastic activity of amniotic fluid increased with advancing gestational age. (3) It was found that the thromboplastic activity determined by plasma recalcification time was parallel with the surfactant concentration of amniotic fluid. (4) The shortening rate of plasma recalcification time in amniotic fluid could estimate well the risk of RDS, and the critical value for RDS was assumed to be about 33%.

Amniotic Fluid↗
PubMed1981

[Human fetal breathing movements: basic analysis and clinical relationship to fetal well-being (author's transl)].

By means of real time B-scan, human fetal breathing movements (FBM) was basically and clinically investigated on 244 observations in 215 pregnancies. The results obtained were as follows. (1) FBM was frequently observed during active sleep in which FHR variability and fetal movement increased. (2) The incidence of FBM increased rapidly from 12.5% at 23-27 weeks to 77-100% at more than 35 weeks gestation, but reduced to 44% at delivery. (3) FBM became more regular and deeper with advancing weeks of pregnancy, especially after 36 weeks of gestation. The frequency of FBM in normal pregnancy was slightly high at 28-29 weeks, but almost the same rates at 30-41 weeks. (4) Maternal mean blood glucose level of 6 cases (72.3 +/- 5.8 mg/dl) in which FBM absent in repeated observations was significantly lower than those of 10 cases (94.7 +/- 14 mg/dl) in which the percentage time spent breathing were 50% or more. (5) Clinically, a relationship between the presence or absence of FBM and Apgar score was not recognized. However, when the percentage time spent breathing was less than 30% or FBM was continuous and considerably deep, the incidence of neonatal asphyxia or FHR abnormality during labor was significantly increased.

Blood Glucose↗
PubMed1981

[Postnatal histogenesis of the cartilage plate of the spinal column -light and electron microscopic observations (author's transl)].

In mice ranging in age from birth to 45 weeks, the cartilage plate in the spinal column was systemically examined by light and electron microscopy. In addition, the proximal end of tibia in 3 week-old mice was studied for comparison. In early life immediately after birth, the nucleus pulposus was separated by cartilage tissue from the ossified vertebral body. The cartilage could be divided into two portions, one portion close to the nucleus pulposus and the other close to the vertebral body. At 1 week, the cartilage toward the nucleus was further divided into two layers, a superficial thin cartilaginous layer close to the nucleus and a deep layer composed of degenerating and degenerated chondrocytes and calcified matrix. After 8 weeks, the deep layer was invaded with numerous irregularly-shaped cavities which contained osteoblasts, osteoclasts and blood vessels. Thus, the deep layer could be considered to be ossified. On the other hand, the cartilage which was near the vertebral body in early life, consisted of chondrocytes which were arranged in column. Thus the cartilage near the vertebral body was thought to be involved in ossification and development of the vertebrated body. From a comparison with the proximal end of tibia, the superficial layer close to the nucleus pulposus, the succeeding deep portion, and the cartilage close to the vertebral body seemed to correspond to the articular cartilage, the secondary ossification center, and the epiphyseal plate of long bones, respectively. Thus, the junction of vertebral bodies was thought to be similar in structure to the joint between long bones. Therefore, the cartilage plate of the spinal column can be regarded to belong to a component of the vertebral body.

Animals↗
PubMed1980

Evaluation of long-term treatment of essential hypertension with guanfacine.

1. Twenty-two patients with moderately severe essential hypertension were treated for a period of 12 months with guanfacine (BS 100-141), a new centrally-acting antihypertensive agent. A twice daily schedule was followed and the dose range of guanfacine was 1-8 mg daily. 2. In twenty patients satisfactory blood pressure responses (diastolic pressure below 95 mmHg) were achieved in both the supine and the standing position. Pulse rate decreased slightly, though not significantly. 3. Tolerance to the pressure-lowering effect of the drug developed during the third or fourth month of therapy. This could be overcome by either increasing dosage or adding a diuretic. 4. All patients reported side-effects, mainly dryness of the mouth and fatigue. These side-effects became less or disappeared at the end of 3 months. Rebound hypertension on discontinuation of therapy occurred in two patients. 5. Plasma concentrations of noradrenaline and adrenaline as well as plasma renin activity were decreased after 1 week of treatment with the drug. 6. Guanfacine in conjunction with a diuretic is a useful drug in the long-term treatment of hypertension. Reduced central sympathetic outflow may be the major mechanism underlying the antihypertensive effect of the drug.

Adult↗
PubMed1980

[Surfactant lipoprotein concentration in amniotic fluid of abnormal pregnancies and premature deliveries (author's transl)].

As shown in our previous report surfactant lipoprotein concentration (SLPC) in amniotic fluid measured by sucrose density gradient centrifugation predicts accurately the risk of RDS. In this study SLPC estimations were made on 91 amniotic fluid samples from abnormal pregnancies, spontaneous premature deliveries and anencephalies. The results were as follows. SLPCs increased in placental insufficiency and severe preeclampsia, especially associated with SFD infant, on the other hand, SLPCs decreased in maternal diabetes (Class B), Rh-isoimmunization and anencephaly as compared with normal pregnancy. In most of premature deliveries SLPCs were higher than those of normal pregnancies except for RDS cases. Present evidence suggests that the maturation of fetal lung is accelerated in severe preeclampsia and placental insufficiency and is delayed in maternal diabetes (Class B), Rh-isoimmunization and anencephaly, and it is considered that in spontaneous premature delivery surfactant production in fetal lung is not accelerated but surfactant excretion from fetal lung into amniotic fluid is enhanced by effect of uterine relaxant such as isoxsuprine or terbutaline.

Adult↗