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Biomedical subjects

M Segawa

Publications and source records attributed to M Segawa.

At least 145 records · Page 8Linked to original sources
PubMed1987

Cadmium-induced osteopathy: clinical and autopsy findings of four patients.

Clinical and autopsy findings of 4 patients with chronic cadmium toxication by peroral uptake of cadmium are reported. Cadmium toxication was liable to occur in multiparous postmenopausal women, and it began with proteinuria, glycosuria, lumbago and bone pain. Then, renal function gradually decreased being accompanied with renal tubulopathy. Autopsy disclosed renal tubulopathy, which consisted of the flattening of the epithelium of proximal convoluted tubules at the peripheral portion and the mild thickening of the tubular basement membrane. There was no primary change in the glomerulus and renal interstitium. Osteomalacia was observed in the vertebrae and several other bones. The degree of osteomalacia was in good agreement with chronic renal tubular dysfunction. A decrease of the estrogen content, in addition to renal tubulopathy due to biological saturation of cadmium, seems to play an important role in the pathogenesis of cadmium-induced osteomalacia.

Acidosis, Renal Tubular↗
PubMed1987

[An electron microscopic study of malignant giant cell tumor of bone].

Three cases of malignant giant cell tumors were studied by light microscope and electron microscope. Light microscopic observation revealed three different types of tumor cells, namely, malignant stromal cells, fibrosarcomatous cell and osteosarcomatous cells. Electron microscopic observation revealed that fibrosarcomatous cells had ultrastructure similar to that of malignant stromal cells. Both types of cells showed nuclear pseudo-inclusions (NPI), and well developed organellae related to matrix synthesis in the cytoplasm. Polysaccharide staining of the same cells revealed positive products in the cytoplasm. Osteosarcomatous cells showed irregular nuclei which contained NPI and well developed r-ER. The cells were located in the non-calcified matrix which consisted of collagen fibers. No alkaline phosphatase activity was observed in this area. These facts suggest that: (1) malignant stromal cells and fibrosarcomatous cells synthesize collagenous stroma as normal fibroblasts do, and (2) osteosarcomatous cells are devoid of the ability to promote matrix calcification.

Adult↗
PubMed1986

Anatomy of Rett syndrome.

Rett syndrome is a clinical entity with a distinct set of signs and symptoms. Its etiology is unknown. We review here our observations in this disorder based upon clinical and polysomnographic examinations which are consistent with a developmental disorder of the monoaminergic neural system. These studies argue for a disorder of the noradrenergic, serotonergic and dopaminergic system arising in the locus ceruleus, raphe nuclei and substantia nigra, respectively. Because events of rapid eye movement sleep appear not disturbed, except for body movements, cholinergic neurons are probably not affected. Disordered physiologic states appear in a characteristic sequence with advancing age. Clinical symptoms associated with the aberrant caudally located neurons appear early and those rostrally located become manifested later. This caudalorostral developmental process attributable to early lesion of monoaminergic neurons may explain the age-related sequence of symptoms of Rett syndrome.

Adolescent↗
PubMed1986

Quantitative comparison of Rh1 (Rho, D) antigen on D, Du and d red cells by radioimmunoassay using 125I-protein A.

Relative Rh1 (Rho, D) antigen contents of the red Rh: 1 (Rh positive, D), Rh: wl (Rh variant, Du) and Rh: -1 (Rh negative, d) cells were estimated from the quantity of 125I-protein A bound to the sensitized red cells. The isotope binding activity to both D and Du cells decreased in parallel with the dilution of anti-D serum. The relative amount of the 125I-protein A bound to Du cells was about one-sixth that of D cells without papain treatment, while no isotope binding was observed in d cells. The Du red cells were quantitatively deficient in Rh1 (Rho, D) antigen activity compared with the D cells. A radioimmunoassay using 125I-protein A was a very useful method for studies regarding measuring the relative amounts of various blood group antigens.

Erythrocyte Membrane↗
PubMed1986

Polysomnography--functional topographical examination of the basal ganglia.

Polysomnographical examinations were performed on two cases with unilateral lesion in the basal ganglia. One (case 1) was a 10-year-old girl with tuberous sclerosis with subependymal nodules on the left thalamostriatal sulcus and rotatory seizures, and pharmacologically the existence of a postsynaptic supersensitivity of the dopaminergic (DA) neurons, was suggested. The other (case 2) was an 8-year-old boy with infarction of the left putamen. Two types of body movements (BMs); gross movements (GM) and twitch movements (TM), were evaluated. The mode of occurrence of these BMs against each sleep stage, the pattern of BMs, and the ratio of the number of TM in the mentalis muscle in stage REM against the number of rapid eye movements (REMs) (ment TM REM/REMs) were estimated. The modulation of these parameters by L-Dopa and pimozide was studied. The pattern of GM reflected the DA activity of the side of the lesion. TM of the contralateral side reflected the pathophysiology of the lesion. TM of the ipsilateral extremities of case 1 showed the pattern of DA hyperactivity, which were reduced by small doses of L-Dopa. In case 2, TM of the ipsilateral extremities showed a normal pattern and rate, which increased markedly after L-Dopa. The TM of the sternocleidomastoideus revealed abnormal ipsilaterally in case 1 and contralaterally in case 2. The ment TM REM/REMs ratio reflected the real function of the DA neurons and did not reflect their hyperfunction due to postsynaptic supersensitivity. The numbers and direction of REMs might reflect the function of the basal ganglia, particularly of the DA neurons.

Basal Ganglia↗
PubMed1986

Growth, psychologic characteristics, and sleep-wakefulness cycle of children with sex chromosomal abnormalities.

This study of girls with Turner syndrome (16 cases) and boys with XXY (two cases) and XYY (eight cases) constitutions was designed to follow the longitudinal growth and to analyze the psychologic findings and the sleeping patterns in them. The growth curves of stature in Turner syndrome were below the 3rd percentile at all ages. The mean of SDS of height in cases less than 5 years old was -2.38, that in cases older than 6 years old -2.40. The shoulders in Turner syndrome have a tendency to broaden with time, in contrast to the development of the pelvis, which is not so good. The height of 47,XYY boys from infancy to 9 years of age was between the 10th and 90th percentiles, with one exception in which the height was above the 90th after 8 years of age. Relatively common psychologic findings in cases with Turner syndrome were as follows: low responsiveness to emotional stimuli, poor emotional expressions, passive and negative mental attitudes, low activity and low productivity, narrow and limited interests, passiveness and common sense adaptability, lower impulsiveness and aggressiveness, etc. The circadian oscillation was observed up to 3 years of age with shifting of the sleeping time to the night period. After that, day sleep gradually tends to decrease with age. Age variation in day and night sleep of an XXY boy was compared with that of a normal child. This showed the normal variation in circadian rhythms in early childhood, although the infant with this syndrome slept more, both day and night, than normal. In early childhood, no difference was noted. Similar studies were performed on a child with the chromosomal aberration XYY and revealed the sleep parameters to be quite normal in infancy and early childhood.

Adolescent↗
PubMed1985

Rett syndrome--an early catecholamine and indolamine deficient disorder?

The results of clinical and polysomnographical examinations on 11 Japanese Rett syndrome cases were summarized to substantiate further our previous results regarding the pathophysiology of the disease. It was concluded that the disease starts early in infancy and takes a progressive course. Each characteristic symptom appears in an orderly sequence which is thought to reflect the sequential systemic involvement of certain neuronal systems. Based on the characteristic symptoms and signs, and polysomnographical studies, we speculated that the initial lesion was the locus coeruleus with a hypoactive noradrenergic system combined with other hypoactive monoaminergic systems, including those of serotonin and dopamine, occurring along with the early developmental course. In later stages, hyperfunction possibly due to postsynaptic supersensitivity of the dopamine system causes the characteristic symptoms of the Rett syndrome.

5-Hydroxytryptophan↗
PubMed1985

Effects of neurosurgical treatment on diffuse slow spike and wave complex: a case of left frontal mass lesion with diffuse slow spike and wave complex (DSSW).

A 10-year-old girl with a mass lesion in the left deep frontal lobe was reported. Clinically, seizures occurred at 3 years and 8 months and became intractable around the age of 5.5 years. EEG initially showed focal spikes on the left fronto-central area and later developed into diffuse slow spike and wave complexes (DSSW). Her seizures were clinically different from those in Lennox-Gastaut syndrome. After a left frontal lobectomy, her intractable seizures completely disappeared with marked EEG improvement and without any neurological deficit. Radiological findings before the operation suggested that the expanding effects extended to the deep temporal structures, adjacent to the frontal lobe. These structures, deep frontal and temporal lobes, both or either, were assumed to be involved in generating DSSW in this case.

Child↗