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Biomedical subjects

M Yonezawa

Publications and source records attributed to M Yonezawa.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Tryptophan and its metabolite concentrations in human plasma during the perinatal period].

The concentration of tryptophan (free and protein bound) and its metabolites in the plasma of the maternal vein and in the umbilical vein, umbilical artery and neonatal vein were determined by high performance liquid chromatography. The plasma levels of tryptophan and most of its metabolites in the umbilical vein and artery were significantly higher than those in the maternal vein. Especially the 3-OHAA level in umbilical blood was approximately 50 times as high as that in maternal blood. The concentration of total tryptophan in the plasma of the neonatal vein showed a marked decrease at one day after birth in comparison with that at birth, but the total kynurenine concentration was not decreased in the plasma of the neonatal vein. In the blood, ratios of free to total tryptophan and kynurenine were kept at a constant level throughout the perinatal period. In conclusion, the present study suggests that tryptophan metabolism may play an important role in fetal development.

Chromatography, High Pressure Liquid↗
PubMed1992

The whale (Odontoceti) spleen: a type of primitive mammalian spleen.

Three spleens from two Odontoceti species were studied histo-anatomically. These spleens consisted of lymphatic nodules, the red pulp (broad sense), and the trabeculo-capsular system composed of the elasto-fibroleiomyocytic tissue. The periarterial lymphatic sheath (PALS) was unclear. Two layers, the intermediate zone and perivenous layer, were distinguishable in the red pulp (broad sense). The perivenous layer was narrow in width and consisted of venules and the intervascular reticular tissue rich in myeloid cells. The collecting and drainage veins were enclosed in this layer. The perivenous layer corresponds to the red pulp (narrow sense) of the common mammalian spleen and may be under involution in a process that probably relates to the remodelling of the intrasplenic vein. The pattern of the arteriovenous communication seemed to be closed, and no ellipsoids were noted around arterial terminals. The Odontoceti spleen has two venous drainage routes (hilar and capsular systems), suggesting a primitive state of evolution, and may be an additional example of the primitive mammalian spleen.

Animals↗
PubMed1991

Localization and developmental change of indoleamine 2,3-dioxygenase activity in the human placenta.

Previously, we pointed out the importance of the kynurenine metabolism in fetuses and neonates. We examined localization and developmental change of indoleamine 2,3-dioxygenase activity in human placenta. The indoleamine 2,3-dioxygenase was found localized in syncytiotrophoblast in the placenta. The indoleamine 2,3-dioxygenase activity was not detected in placenta in the early stage of gestation. It was first detected at around 14 weeks of gestation, increased rapidly thereafter and was maintained at high levels till near term. The indoleamine 2,3-dioxygenase activity was significantly lower in placenta with retarded intrauterine development. These results suggest the importance of placental indoleamine 2,3-dioxygenase during fetal development.

Female↗
PubMed1990

[The effects of light exposure on plasma concentrations of melatonin, LH, FSH and prolactin in women].

The effects of light exposure on plasma concentrations of melatonin, LH, FSH and prolactin were studied in 11 normal cycling women during their follicular phases. Blood samples were obtained via an indwelling venous catheter every 10 min. for 2.5 hours starting at 9:30 and 21:30h. For the blood samplings taken at night, six women were kept in a dark room and were permitted to sleep. Their blood samples were obtained using a flashlight (5-10 lux) without their rest being disturbed. However, the other five women were exposed to light (3,000 lux at eye level) and awakened from 22:40 to 24:00h. Plasma melatonin concentrations in the morning decreased from 48.7 +/- 11.6 pg/ml at 9:30h to 24.7 +/- 4.0 pg/ml at 12:00h. On the other hand, plasma melatonin concentrations at night increased from 65.4 +/- 9.6 pg/ml at 21:30h to 138.2 +/- 28.6 pg/ml at 24:00h. The pulsatile LH secretion was changed from the type of "high frequency, low amplitude" in the morning to the type of "low frequency, high amplitude" at night. Nocturnal FSH concentrations were lower than diurnal ones, but nocturnal prolactin concentrations were higher than diurnal ones. Nocturnal concentrations of melatonin were suppressed 40 min. after the light exposure (from 117.4 +/- 11.4 pg/ml at 22:40h to 74.6 +/- 13.9 pg/ml at 23:20h). On the the other hand, the light exposure increased plasma prolactin concentrations from 10.9 +/- 4.1 ng/ml at 22:40h to 17.0 +/- 4.4 ng/ml at 22:50h, maintained those higher levels for 20 min. and decreased them gradually after 23:20h. With the light exposure, mean values of nocturnal LH concentrations were increased from 11.9 +/- 1.5 mIU/ml before exposure to 14.2 +/- 1.8 mIU/ml after exposure, and those of FSH were also increased from 5.9 +/- 0.4 mIU/ml to 6.3 +/- 0.4 mIU/ml. These results showed that the secretion of melatonin, as well as LH, FSH and prolactin had daily rhythms and that melatonin and prolactin showed different responses to light exposure, suggesting different control mechanisms for the secretion of those two hormones.

Adult↗
PubMed1990

Peripheral neuropathy in xeroderma pigmentosum.

The pathology of the peripheral nervous system (PNS) in 2 autopsied cases of group A xeroderma pigmentosum (De Sanctis Cacchione syndrome) are presented. Motor nerves including those of the oculomotor systems were severely affected, but involvement of the sensory system was even more marked. Minor hypertrophic changes were present in the distal portions of the peripheral nerve trunks, but there was no appreciable difference in the density of myelinated nerve fibres between proximal and distal levels. Morphometric data including teased fibre analyses and g ratio scattergrams suggest that the underlying pathogenetic mechanism is that of a neuronopathy. Unmyelinated axons were also severely depleted. Review of the previous literature revealed that the pathological changes of the PNS in group A xeroderma pigmentosum are thought to be slowly progressive, which is also suggested by the severe and widespread sclerotic changes of the CNS in the present 2 cases.

Adult↗
PubMed1990

Adrenoleukodystrophy associated with cerebral arteriovenous malformation.

Adrenoleukodystrophy (ALD) is now considered to be an X-linked recessive peroxisomal disorder. We report the case of a patient with ALD associated with a left parietal arteriovenous malformation (AVM) who deteriorated progressively six months after recovery from a hemorrhage of the AVM. Serial CT scans and MR imagings showed progressive demyelination spreading from the affected area. This case suggests that local brain damage due to AVM hemorrhage may accelerate the progress of demyelination.

Adrenoleukodystrophy↗
PubMed1990

Acquired radioresistance after low dose X-irradiation in mice.

Low doses (2.5-15 cGy) of X-irradiation two months prior to a second exposure to a sublethal dose enhanced the survival rate in mice. Optimal and significant increase was observed with 5-10 cGy. Endogenous spleen colony counts (endo-CFUs) after 7 Gy increased by a factor of about 1.7 in mice pre-irradiated with 5-10 cGy, while the number of blood forming stem cells (CFUs) in the pre-irradiated group did not exceed that in the sham-irradiated control group at the period of the second exposure (two months after irradiation with 5 cGy). The low dose exposure seems to stimulate recovery of blood forming stem cells after the second irradiation and favors a decrease in the incidence of bone marrow death.

Animals↗
PubMed1990

[A determination of anti-insulin receptor antibody in serum--a radioreceptor assay excluded the influence of insulin and anti-insulin antibody].

We studied an anti-insulin receptor antibody (IRAb) assay that excludes the influence of serum insulin and anti-insulin antibody in patients with anti-insulin antibody and normal subjects. The placental membranes strongly bound with 125I-insulin at 4 degrees C. The insulin specificity of the radioreceptor assay was confirmed by adding excess non-labeled insulin and other human hormones to the assay system. The strong correlation between the receptor binding reactivity (%) and the anti-insulin antibody levels was noted in the conventional direct IRAb assay (r = -0.95), but not in the present IRAb assay (r = 0.46) in 10 clinical samples. The placental membranes were stable as the target insulin receptor for IRAb assay at -80 degrees C for at least 4 months. A significant difference in IRAb levels was found between 10 patients with positive anti-insulin antibody and 20 normal controls (p less than 0.01, student t test). The coexistence of insulin and anti-insulin antibody were removed by absorbance to silicagel and by utilizing the two-step (indirect) assay, respectively. IRAb assay without the influence of serum cofactors showed excellent reproducibilities (CV 4.4% (N = 5) and 12.5% (N = 5) in within and between assay variations, respectively).

Autoantibodies↗
PubMed1990

[Clinical significance of measurement of plasma melatonin concentration in women with irregular menstrual cycles].

To study the effects of melatonin on the human hypophyseal ovarian axis, we measured the concentrations of melatonin in the plasma of women with a regular menstrual cycle and of women with an abnormal menstrual cycle, at days 5 through 10 after the onset of menstruation or withdrawal bleeding. In seven women with a regular menstrual cycle, there was a tendency for the plasma melatonin concentration to gradually decrease chronologically from 49.0 +/- 9.8pg/ml (M +/- S.E.) at 9:30 h to 19.0 +/- 4.0pg/ml at 12:00 h. On the other hand, the plasma melatonin concentration at 21:30 h was 50.3 +/- 7.4pg/ml which was almost the same as the level at 9:30 h, while the concentration during the night significantly increased chronologically to 106.3 +/- 28.6pg/ml at 24:00 h. By comparing the plasma melatonin concentration measured during the day with that measured during the night, a significant difference was discovered after 21:40 h (p less than 0.05). The plasma melatonin concentration at 10:00 h and 22:00 h in 20 women with a regular menstrual cycle was 28.1 +/- 3.4pg/ml and 72.2 +/- 9.9pg/ml, respectively, showing a diurnal rhythm with a significantly higher level during the night than during the day. On the other hand, the plasma melatonin concentration in most of the women with an anovulatory cycle or amenorrhea was within the range of the mean level of +/- 1.5 x the standard deviation obtained from the 20 women with a regular menstrual cycle. However, an increase in plasma melatonin during the night was not found in three of nine women with an anovulatory cycle and one of two women with second grade amenorrhea.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian Rhythm↗
PubMed1990

[A case of three-year-old boy with periodic apnea during waking and sleep, severe psychomotor retardation and hypotonia].

We presented a 3-year-old boy, a product of consanguineous parents, with periodic apnea during waking and sleep states, severe psychomotor retardation and hypotonia. According to polysomnographical recordings, he exhibited frequent central apneas which decreased in frequency and regularity in the stage REM. He showed abnormal background EEG, undifferentiated sleep stage and very short duration of stage REM. The initiation of breathing after apnea was often accompanied with generalized muscles contraction like a startle response. In the waking state the apnea induced generalized muscular hypotonicity and the decline of wakefulness. Arterial CO2 and O2 saturation was within normal limits. It was suggested that the malfunction of the brain stem responsible for the control of breathing, sleep-wakefulness cycle and determination of sleep stages was closely connected with the pathogenesis of abnormal breathing patterns.

Apnea↗
PubMed1989

Hodgkin's disease in a killer whale (Orcinus orca).

Hodgkin's disease (HD) is reported in a killer whale (Orcinus orca). Generalized lymphadenopathy and splenomegaly were noted at necropsy and histopathological examination revealed diffuse proliferation of atypical large cells with huge eosinophilic nucleoli. They were often multinucleated, and binucleated forms characteristic of Sternberg-Reed cells of human HD were occasionally present. There was no cytological atypia in the background lymphocytes. Thus, the lesion was identified as analogous to HD in man. To our knowledge, this is the first recorded case of HD in the killer whale.

Animals↗
PubMed1989

Radiation protection by Shigoka extract on split-dose irradiation in mice.

Radioprotective effect of a Shigoka extract was studied on split-dose irradiation. Mice were exposed to 4 Gy X 4 or 3 Gy X 4 for examining survival ratio or hemogram, respectively. The extract was i.p. injected immediately after each irradiation. The extract significantly (p less than 0.001) increased the survival ratio, and it increased leukocyte count within the period of the death (days 2-12 after the final exposure). Cerebral hemorrhage after 4 Gy X 4 was diminished by the extract. Recovery of leukocytogenesis seems much more important for survival at split-dose irradiation than at single acute irradiation.

Animals↗
PubMed1989

[ELISA for platelet-associated IgG, IgM, and C3, and their clinical application].

The platelet-associated IgG (PAIgG) has been reported to elevate in the patients with idiopathic thrombocytopenic purpura (ITP) and other autoimmune diseases. However, low PAIgG levels have been often recognized in thrombocytopenia. We speculated about the increasing of other platelet-associated proteins in those patients, and tried to determine platelet-associated IgM (PAIgM) and platelet-associated C3 (PAC3) using a high sensitive competitive micro-ELISA as well as PAIgG. Our results showed the specific elevation of PAIgM and PAC3 in thrombocytopenia as well as the PAIgG level (p less than 0.01). Further, the weak correlations among these levels were found (PAIgG/PAIgM: n = 7, correlation coefficient (r) = 0.55, PAIgG/PAC3: n = 73, r = 0.61, PAIgM/PAC3: n = 56, r = 0.39). We discussed on the possibility that the PAIgM and PAC3 also could be an indicator for the platelet injury and may cause the short platelet life span resulting thrombocytopenia as well as PAIgG.

Autoantibodies↗
PubMed1987

Differentiation between eclampsia and cerebrovascular disorders by brain CT scan in pregnant patients with convulsive seizures.

Six pregnant women with convulsions between 25 to 40 weeks of gestation were experienced. Among them, 4 patients were diagnosed as having intracranial hemorrhage and two as simple eclampsia. With the aid of brain CT scan, one case of arteriovenous malformation was detected and treated surgically with good prognosis for both the mother and the fetus. Two patients were diagnosed to have cerebral hemorrhage with subsequent penetration into the lateral ventricles and were treated conservatively. Their fetuses were delivered alive by cesarean section, but the mothers expired. The other patient with cerebral hemorrhage was treated surgically, and both the mother and the fetus survived. One of the simple eclampsia patients was noted to have a growth retarded fetus at 32 weeks of pregnancy with subsequent intra-uterine death, but the mother recovered after conservative treatment. Another patient at 40 weeks of pregnancy was also treated conservatively and both the fetus and the mother survived. Brain CT scan findings differed between these two eclampsia patients; local brain edema for the second patient and generalized brain edema for the first patient. Thus more active application of brain CT scan is recommended in managing pregnant patients with convulsions.

Adult↗
PubMed1987

[Postoperative outcome of residual pyelocaliceal stones].

The purpose of this paper is to investigate the outcome of postoperative residual stones and their influence to the renal function. We followed up 65 patients (73 kidneys) with residual stones after conventional operation. The follow-up period was on an average 11 years and 9 months. 50 of 73 kidneys were infected before surgery. The most frequently cultured organisms was Proteus mirabilis. Urinary infection persisted in 34 of 50 kidneys after surgery. The residual stones smaller than 5 mm existed in 10 kidneys, of which 7 became sterile. The stones between 5 and 10 mm existed in 18 kidneys, of which 7 (38.9%) became sterile, but in 22 kidneys with stones larger than 10 mm, the infection was not eliminated but in 2 kidneys. Conversely, postoperative infection was never found in 23 kidneys being sterile before operation. Residual stones increased in size in 39 kidneys, did not change in 19 kidneys, diminished in 3 kidneys, fell to the ureter requiring surgery in 7 kidneys and the spontaneous passage of stones was observed in 4 kidneys. In comparing the stone increase group with that of stone stable, the former had a high frequency of stones larger than 5 mm, of postoperative urinary infection and of many stone forming factors. We studied the change of renal function only by IVP in 71 kidneys. Thirty-two kidneys with residual stones and infection showed moderate or severe deterioration of renal function in a large majority of cases. Conversely, in 24 of 34 kidneys without infection, the renal function was stable and only 6 kidneys showed moderate or severe deterioration of renal function.

Follow-Up Studies↗