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Biomedical subjects

M Kawamura

Publications and source records attributed to M Kawamura.

At least 721 records · Page 40Linked to original sources
PubMed1987

In vitro calcification in human osteoblastic cell line derived from periosteum.

Human osteoblastic cell cultures were established from human periosteum, identified on the basis of high alkaline phosphatase activity in the confluent state. The cells in the growing state showed a fibroblastic morphology and grew to form multiple layers. The cells could spontaneously calcify, and the process was accelerated by alpha-glycerophosphate. Minerals deposited on the cells consisted exclusively of calcium and phosphorus, and matured into hydroxyapatite crystals. The calcification was stimulated by the treatment with 1 alpha,25-dihydroxy-vitamin D3. These results indicate that the osteoblastic cells have the capacity to differentiate into osteocytes and form calcified human bone tissue in vitro.

Adult↗
PubMed1987

[ATPase inhibitory activities found in the soluble fraction of an ascidian (Halocynthia rotezi) muscle].

Crude extracts obtained by water extraction from the muscle of an ascidian (Halocynthia rotezi) are shown to possess an inhibitory activity on ATPase [(Na, K) ATPase, TF1-ATPase, HMM-ATPase]. Gel filtration of the extract with Sephadex G-10 separated the activity into two peaks, and the latter peak (inhibitor II) was further purified by HPLC. This inhibitor was non-competitive for ATP and associated firmly with the (Na, K) ATPase.

Animals↗
PubMed1987

Release of atrial natriuretic polypeptide by graded right atrial distension in anesthetized dogs.

In order to verify the contribution of right atrial pressure to atrial natriuretic polypeptides (ANP) release, we measured plasma levels of immunoreactive (ir)-ANP when graded rise of right atrial pressure was executed in anesthetized dogs. Increasing right atrial pressure (RAP) from 2.7 +/- 0.6 to 9.0 +/- 0.7 mmHg, plasma levels of ir-ANP in aorta tended to increase by 33% but not significantly (p greater than 0.05). However, when RAP was increased from 9.0 +/- 0.7 to 17.0 +/- 1.1 mmHg, ir-ANP levels in aorta were significantly (p less than 0.05) increased by 132% of control within 5 min from the start of RAP elevation. The RAP elevation produced a sustained increase in plasma levels of ir-ANP. There was a positive correlation between right atrial pressure and plasma levels of ir-ANP. The plasma levels of ir-ANP were similar between aorta and pulmonary artery. These results demonstrate that increasing atrial pressure is closely correlated with ANP release and ANP is not greatly metabolized by pulmonary circulation.

Animals↗
PubMed1987

A comparative study of attenuation correction algorithms in single photon emission computed tomography (SPECT).

A computer based simulation method was developed to assess the relative effectiveness and availability of various attenuation compensation algorithms in single photon emission computed tomography (SPECT). The effect of the nonuniformity of attenuation coefficient distribution in the body, the errors in determining a body contour and the statistical noise on reconstruction accuracy and the computation time in using the algorithms were studied. The algorithms were classified into three groups: precorrection, post correction and iterative correction methods. Furthermore, a hybrid method was devised by combining several methods. This study will be useful for understanding the characteristics, limitations and strengths of the algorithms and searching for a practical correction method for photon attenuation in SPECT.

Algorithms↗
PubMed1987

Monte Carlo estimates of absorbed dose rate in various tissues and organs.

A computer program based on the Monte Carlo technique was developed for calculation of absorbed dose rate in various tissues and organs. The accuracy of the program was tested by reproducing Berger's values of the specific absorbed fractions for point isotropic sources in water, and a good agreement with those obtained by the moments method was found within an error of several percent. In comparing with experiment and other Monte Carlo results, good agreement was also obtained within the range of statistical error. The absorbed dose rate for an 123I, 124I, 125I, 126I and 99mTc point source and their specific dose constants in various tissues and organs were calculated using this program. This computer program has the mass energy absorption and attenuation coefficients for 69 tissues and organs as a database file, and can be extended to various radionuclides used in nuclear medicine by adding their nuclear data to the program.

Humans↗
PubMed1987

Pathogenicity and immunogenicity in chickens of Newcastle disease viruses isolated from wild ducks. Brief report.

Three Newcastle disease viruses (NDV) isolated from wild ducks in Japan were evaluated for their biological activities, pathogenicity and immunogenicity against one-day-old chickens. One isolate was of the mesogenic type and the other two were of the lentogenic type for chicken. The lentogenic isolates could induce enough immunity in chickens to protect them from challenge with a virulent strain of NDV.

Animals↗
PubMed1987

Complementation studies with clinical and biochemical characterizations of a new variant of multiple sulphatase deficiency.

A patient with a new variant of multiple sulphatase deficiency (MSDv) is reported. Unlike the usual type, onset was late and progress was slow. The phenotypic changes were those usually seen in multiple sulphatase deficiency but much milder. Cytoplasmic accumulations were found in skin fibroblasts, and urinary mucopolysaccharides and sulphatides were high. Arylsulphatases A, B and C (ASA, B and C), heparan N-sulphatase sulphoiduronate sulphatase, and N-acetylgalactosamine 6-sulphatase all had low activity in lymphocytes and cultured skin fibroblasts. Complementation for ASA activity was found in hybrids between MSDv and metachromatic leukodystrophy (MLD) as well as between multiple sulphatase deficiency (MSD) and MLD. Complementation for ASC activity was also seen in hybrids between MSDv and X-linked ichthyosis (XLI), and between MSD and XLI. However, neither ASA nor ASC activity increased in hybrid cells of MSDv and MSD. These results suggested that the mutations of MSDv and of MSD were allelic, although of different phenotypes.

Adult↗
PubMed1987

Enhanced degradation of low density lipoprotein in human monocyte-derived macrophages associated with an increase in its free fatty acid content.

Low density lipoprotein (LDL) rich in oleic acid (designated FFA-rich LDL) was produced by the reconstitution technique. FFA-rich LDL, like acetyl LDL, moved faster than native LDL in agarose gel electrophoresis. While FFA-rich LDL was observed to degrade far less than natural LDL in lymphocytes, its degradation in monocyte-derived macrophages was three times higher than that of natural LDL or LDL reconstituted without the addition of oleic acid. A competitive study showed that the catabolism of FFA-rich LDL in macrophages may be influenced by systems other than the acetyl LDL receptor.

Cells, Cultured↗
PubMed1987

Retinal vascular loss in idiopathic central serous chorioretinopathy with bullous retinal detachment.

Three patients with idiopathic central serous chorioretinopathy (ICSC) and bullous retinal detachment (RD) were examined at least 2 years after the onset of the disease in one patient and over 10 years in the other two patients. There were large areas of retinal pigment epithelium (RPE) degeneration in each patient. Interestingly, there was loss of retinal vascular trees in the inferior peripheral retina where the subretinal fluid presumably persisted for a long time. In one patient, there was a retinal neovascularization with sea-fan formation along the border of the vascular loss. To the authors' knowledge, this finding has not been described in the literature.

Adult↗
PubMed1987

Alloaesthesia.

Alloaesthesia is a condition in which a sensory stimulus given on one side of the body is perceived at the corresponding area on the other side. We observed this in 20 out of 123 patients with hypertensive cerebral haemorrhage in the acute stage (within twenty days), all except 1 in the right hemisphere. This phenomenon was observed in 17 out of 35 patients with right putaminal haemorrhage and only 1 out of 30 patients with right thalamic haemorrhage, suggesting it may be useful in differentiating putaminal from thalamic haemorrhage in the right hemisphere. Three patients, with cervical tumour, cervical disc herniation and multiple sclerosis also showed alloaethesia. They had anterolateral lesions of the spinal cord. The cerebral and spinal cord lesions presented similar symptomatic characteristics of alloaesthesia. It is suggested that as alloaesthesia is produced by noxious stimuli not only in spinal cord but also in cerebral lesions it may represent an elementary sensory disturbance of sensory pathways, and not a higher cortical dysfunction.

Cerebral Hemorrhage↗
PubMed1987

Electropalatographic analysis of apraxia of speech in a left hander and in a right hander.

Two cases with 'pure' apraxia of speech are reported. The articulatory disturbances were quite similar. One of the two cases was a left-handed male with a subcortical haemorrhage and the other a right-handed male with a cerebral infarct. The MRI and CT scans showed that the first case had a lesion that mainly involved the right precentral gyrus and its deep white matter, and that the second had a lesion mainly affecting the lower parts of the left precentral and postcentral gyri and their deep white matter. These findings and a literature review suggest that a corticosubcortical lesion of the lower part of the left precentral gyrus in most right handers and a lesion of the symmetric region in the right hemisphere in some left handers cause apraxia of speech. The omission errors for sounds articulated by the tongue and the hard palate were analysed using electropalatography, which records visually the dynamics of the palatolingual contact. The results demonstrated that there were three kinds of omission errors: true omissions (no palatolingual contact); omissions with incorrect contact (palatolingual contact for a different sound or undifferentiated sound); and omissions with correct contact (correct palatolingual contact for a target sound). The latter two types of omission error were observed for initial consonants and they were probably caused by a delay in air flow. The patients also showed a tendency to substitute one of the two consonants/t, t/for other sounds, which suggested that they had difficulty in the inhibition of tongue activity.

Adult↗
PubMed1987

Antigenic variation of Newcastle disease viruses isolated from wild ducks in Japan.

Nineteen strains of Newcastle disease virus (NDV) isolated from wild ducks in Japan were placed into 4 distinct antigenic groups on the basis of their reactivities to 8 monoclonal antibodies against the HN molecule of NDV in hemagglutination inhibition tests. The NDV strains of duck origin were antigenically distinct from NDV-B1 and NDV-Miyadera originated from chickens, and varied in their virulence to chicken embryos. No apparent correlation was found between the antigenicity of the HN molecule and virulence.

Animals↗