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Biomedical subjects

T Takamatsu

Publications and source records attributed to T Takamatsu.

At least 73 records · Page 4Linked to original sources
PubMed1991

Comparison of protein tyrosine phosphorylation and morphological changes induced by IL-2 and IL-3.

We constructed cell lines which can proliferate in response to IL-2 or IL-3 by introducing a wild-type and mutant forms of cDNAs encoding the human IL-2R p75 chain into an IL-3 dependent hematopoietic cell line which expresses the p55 chain of the IL-2R. We compared early events that were induced in these cells by IL-2 and IL-3. Analysis of protein tyrosine phosphorylation showed that two common protein bands, pp95 and pp90, were phosphorylated by stimulation of either IL-2 or IL-3, suggesting the possible sharing of part of a signal transduction pathway between IL-2R and IL-3R. Comparison of protein tyrosine phosphorylation profiles induced by IL-2 and IL-3 among a variety of cell lines revealed that the pp90 band is the common tyrosine phosphorylation substrate in the cell lines examined, although the general tyrosine phosphorylation pattern differed in each cell line. Mutant p75 molecules incapable of inducing tyrosine phosphorylation could bind and internalize IL-2, but could not support cell growth. We also found that swift changes of cytoskeletal protein organization are one of the early events caused by signal transduction through either IL-2R and IL-3R. Reorganization of cytoskeletal proteins seems to be associated with protein phosphorylation, as a significant portion of pp90 was found in a detergent-soluble fraction in IL-2 or IL-3 treated cells.

Base Sequence↗
PubMed1991

Imaging of calcium wave propagation in guinea-pig ventricular cell pairs by confocal laser scanning microscopy.

We describe here the use of a confocal laser scanning microscope for imaging fast dynamic changes of the intracellular calcium ion concentration ([Ca2+]i) in isolated ventricular cell pairs. The scanning apparatus of our system, paired galvanometer mirrors, can perform narrow band scanning of an area of interest at a high temporal resolution of less than 70 msec per image. The actual [Ca2+]i is obtained directly through the fluorescence intensity of injected fluo-3, which responds to changes of [Ca2+]i in optically sectioned unit volumes of the cell. Images of the calcium wave obtained during propagation between paired cells revealed that the wavefront is constant in shape and propagates at constant velocity without any delay at the cell-to-cell junction. The confocal laser scanning microscope with depth-discriminating ability is a valuable tool for taking pictures of the sequence of biological events in living cells.

Animals↗
PubMed1990

MR imaging of spastic diplegia. Comparative study between preterm and term infants.

Eighteen children (eleven preterm birth and seven term birth) with clinical evidence of spastic diplegia (SD) were studied to clarify the differences of the lesions between preterm and term SD on MR imaging. All with preterm birth showed similar abnormalities of the periventricular white matter represented by high intensity in T2-weighted imaging and low intensity in T1 imaging. It seemed that the lesions were periventricular leukomalacia (PVL) and dysmyelination pathologically and correlated well clinically with spastic diplegia. SD with term birth group showed various lesions, two brain anomalies (schizencephaly and corpocephaly), one PVL, four showed no lesions. We suggested that SD with preterm birth is not only a clinical but also a pathological entity.

Brain↗
PubMed1990

Calcium waves in mammalian heart: quantification of origin, magnitude, waveform, and velocity.

A dual, digital, indo-1 fluorescence imaging system was used to obtain high-speed ratiometric images of [Ca2+]i waves in single voltage-clamped mammalian cardiac cells. The spatiotemporal origin of [Ca2+]i waves in depolarized cells was detected as the spontaneous appearance, over 100-300 ms, of domelike regions of elevated [Ca2+]i, approximately 20 microns in diameter and 300 nM at the center. Images of [Ca2+]i taken at 67-ms intervals during propagation of [Ca2+]i waves revealed that the [Ca2+]i wave front was 1) constant in shape, 2) spatially steep, typically rising from 500 to 1200 nM in about 10 microns, and 3) propagating at constant velocity, typically 100 microns/s at 22 degrees C. The observed spatial and temporal patterns of origin and propagation of [Ca2+]i waves are consistent with the hypothesis that [Ca2+]i waves arise from propagating Ca2(+)-induced release of Ca2+ mediated by diffusion of cytosolic Ca2+. The [Ca2+]i waves are smaller in peak magnitude and can occupy a larger fraction of the cell than thought previously on the basis of indirect observations.

Animals↗
PubMed1990

[Effect of bite force on parotid secretion in human].

To determine the physiological roles of periodontal mechanoreceptors in parotid salivary secretion, we studied the effects of strength and frequency of unilateral bites on the salivary secretion from both sides of human parotid glands. Parotid saliva was collected bilaterally via modified Lashley cups, and the flow rate of parotid saliva was measured with a device using a strain gauge. The bite force was monitored with a pressure transducer. In the first experiment, subjects were constantly occluded for one minute at 80 strokes per minute at strengths of 5, 10, and 20 kg. In the second experiment, subjects were occluded for one minute at a constant force of 10 kg at frequencies of 20, 40, 80, and 120 strokes per minute, or subjects were continuously clenching for one minute. The flow rate of parotid saliva gradually increased with increasing bite strength, while it gradually decreased with increasing bite frequency. In unilateral bites, the salivary flow rate of the ipsilateral parotid gland was greater than that of contralateral parotid gland, at any strength and frequency. These results suggest that periodontal mechanoreceptors are involved in parotid salivary reflexes initiated by bite force stimuli.

Bite Force↗
PubMed1990

[A case of autoimmune hemolytic anemia and bullous pemphigoid-like skin lesion combined with idiopathic thrombocytopenic purpura].

A case of autoimmune hemolytic anemia (AIHA) and bullous pemphigoid (BP)-like skin lesion combined with Idiopathic thrombocytopenic purpura (ITP) is reported. A 25-years-old male, who had been diagnosed as ITP and treated at another hospital, was admitted in this hospital recently complaining of disseminated bullous-vesicular eruptions on the whole body and autoimmune hemolytic anemia. Examinations, disclosed that RBC was 364 X 10(4)/microliters, reticulocyte 40, platelet 3000/microliters, direct and indirect Coombs test positive, and platelet Coombs consumption test was positive leading to the diagnosis of AIHA and ITP, known as "Evans syndrome." Vesicular biopsy-findings and immunofluorescence study showed suspicion of BP, but clinical course and blister was not improved though the administration of prednisolone was performed. Reports of cases of BP complicated by Evans syndrome are very few. AIHA, ITP and BP are considered to have autoimmune disorders and their pathogenetic mechanism are discussed. This patient consulted another hospital one year later, when we heard that skin eruptions already had disappeared.

Adult↗
PubMed1989

[Silent period and initial occlusal sliding time in patients with premature contacts].

This study was designed to examine the relationship between frequency of silent period and initial occlusal sliding time. The subjects consisted of three volunteers with normal occlusal contacts and three patients with premature contacts. Electromyograms of the bilateral masseter muscles, initial occlusal contacts and jaw movements during the habitual tapping (20-25) were synchronously recorded and replayed using Takamatsu's technique. Results were as follows: 1. The frequency of silent period in the bilateral masseter muscles was 95-100% in subjects with normal occlusal contacts and 34-53% in patients with premature contacts. 2. The silent period latency in three normal subjects was 8.9 +/- 1.3 msec in the left masseter and 13.9 +/- 2.2 msec in the right masseter. The silent period latency in three patients with premature contacts was 12.4 +/- 2.6 msec in the left masseter and 13.9 +/- 8.2 msec in the right masseter. 3. The duration of silent period in three normal subjects was 12.4 +/- 2.6 msec in the left masseter and 11.1 +/- 3.7 msec in the right masseter. The duration of silent period in three patients with premature contacts was 9.1 +/- 1.7 msec in the left masseter and 11.1 +/- 5.6 msec in the right masseter. 4. Initial occlusal sliding time in three subjects with normal occlusal contacts was less than 30 msec, and 98% of all slidings lasted for less than 15 msec. Initial occlusal sliding times in patients with premature contacts were distributed between 6 and 80 msec (40%: 6 to 15 msec, 60%: greater than 15 to 80 msec).(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Occlusion, Traumatic↗
PubMed1989

[Clinical study of bruxism. Comparison of muscle activity during sleep between patients conscious of bruxism and those not conscious of the condition].

Bruxism has been considered to be one of the most important factors in accelerating the progression of established periodontal lesions. However the objective diagnostic method has not yet been established. At present, diagnosing bruxism might mainly be dependent on interview. The purpose of this study was to compare and analyze the differences in frequency and duration of bruxism between a group of patients conscious of the problem and a group not conscious of bruxism. After interviewing, the subjects were divided into two groups; 1) group A consisted of 8 subjects who were conscious of bruxism and 2) group B of 8 subjects who were not conscious of bruxism. The frequencies and durations of muscle activity during sleep at night were compared between groups A and B using EMG with a telemetric method. In the one-night observation, muscle activity supposed to be bruxism was observed in both groups. Significant differences in frequencies of muscle activity were not found between the two groups. A similar result was obtained in the durations of muscle activity. In a seven-day observation, muscle activity was seen in all three volunteers, although marked differences were not found among them. A long duration of muscle activity was found under conditions of physical or mental stress. The results of this study showed the difficulty of diagnosing bruxism by interview and the necessity of an objective method.

Bruxism↗
PubMed1989

Soluble interleukin-2 receptors in plasma cell dyscrasias.

Levels of the soluble form of the interleukin-2 receptor (sIL-2R) were evaluated in the peripheral blood of 69 patients with plasma cell dyscrasias. A close relationship was seen between serum sIL-2R levels and clinical features. Among patients with normal BUN and creatinine levels, the mean (+/- 1SD) level of sIL-2R in 44 patients with multiple myeloma (MM) was higher than that of normal controls (457 +/- 227 U/ml vs 288 +/- 124 U/ml, P = 0.01). The mean level of sIL-2R in eight patients with primary macroglobulinemia was 722 +/- 251 U/ml. In MM, those with active or refractory disease showed a significantly higher mean level of sIL-2R than those in the remission phase (577 +/- 240 U/ml vs 335 +/- 103 U/ml, P = 0.01). There was a negative correlation between sIL-2R and hemoglobin levels in MM patients (r = -0.45, P = 0.01). Five patients with complications of renal insufficiency had elevated levels of sIL-2R. In a longitudinal study of a patient with plasmacytoma and an extremely high sIL2-R level, the sIL-2R level showed a strong relationship with tumor burden. Patients with high sIL-2R levels generally had a poor prognosis than those with normal levels. Thus a high sIL-2R level may be an indicator of a poor prognosis in MM.

Aged↗
PubMed1989

[Dynamic local cerebral circulation study in patients with cerebral diseases--using 99mTc-HSA-D mainly compared with 99mTc-HSA].

We have been using 99mTc-RBC and 99mTc-HSA for cerebral angiography and measurement of the local cerebral blood volume (LCBV) and cerebral/peripheral hematocrit ratio (alpha). 99mTc-HSA, however, has a problem of poor stability in the blood. We conducted basic and clinical studies on 99mTc-HSA-D, a ready-to-use preparation with good stability in the blood. We measured the regional cerebral circulation dynamics in patients with cerebral diseases in comparison with 99mTc-RBC and 99mTc-HSA. 99mTc-HSA-D and 99mTc-RBC showed more than a 90% retention ratio in the blood 60 min after administration, and good SPECT images were obtained using these two pharmaceuticals. On the contrary, 99mTc-HSA was unstable and its retention ratio was 60s% 60 min after administration. 99mTc-HSA does not provide good SPECT images due to free 99mTcO4- which seems to be liberated from 99mTc-HSA in the body, etc. There were no adverse reactions or abnormal laboratory findings caused by the 99mTc-HSA-D administration in any of the patients. Based on these results, it is surmised that 99mTc-HSA-D is clinically useful for measurement of the cerebral blood volume and cerebral/peripheral hematocrit ratio (alpha).

Adult↗
PubMed1988

A quantitative analysis of human astrocytosis.

The number of astrocytes in an atrophic human brain was counted with the aid of immunohistochemistry for glial fibrillary acidic protein. Microscopically, astrocytosis was remarkable in the cerebral neocortex and white matter. Taking the cortical atrophy into consideration, however, the total number of astrocytes in the cortical layers II-VI was not increased. The number of astrocytes in the white matter was not increased either. It is indicated that astrocytosis does not always mean hyperplasia (net increase of total number) of astrocytes.

Astrocytes↗
PubMed1988

Changes in nuclear DNA content and cell size of injured human corneal endothelium.

To understand how human corneal endothelium compensates for cell loss, nuclear DNA-cytofluorometry and cell morphometry were carried out on injured corneal endothelium. The examined corneas included two cases of keratoconus complicated with acute hydrops and one without acute hydrops, two cases of herpetic keratitis, one case of post-intracapsular cataract extraction (post-ICCE) and one case of luetic keratitis. The endothelial cell layer was separated from Descemet's membrane and double-stained with Rhodamine-labeled wheat germ agglutinin-lectin (WGA) and 4',6-diamidino-2-phenylindole dihydrochloride (DAPI). The area of each cell was measured with a color image analyser and compared with its cytofluorometric nuclear DNA content. The endothelium in apparently intact regions of the diseased corneas showed the same DNA-ploidy pattern and cell area as the physiological corneas. However, endothelial cells in injured regions had greater area, even in diploidy, than in presumably normal ones and showed a larger number of hyperploid cells ranging from 4C to 36C. Hyperploid cells consisted of many multinucleates and few polyploidies and had extremely large and bizarre cytoplasm. All injured corneas were accompanied by cells with numerous micronuclei. A few asymmetrical 4C-binucleates (with DNA values such as 1.3 plus 2.6C) appeared in the case of the post-ICCE. It is concluded that damage to human corneal endothelial cells in vivo results in cell enlargement with or without DNA synthesis. Those changes appear more severe in diseased corneas than in the situation of physiological aging which we have reported previously. In severe cases, micronuclei, polyploid cells and multinucleated giant cells are frequent, thereby suggesting a possible long-persistent metabolic impairment of the endothelium after severe damage to the cornea.

Adolescent↗
PubMed1988

Microscopic tomography by laser scanning microscopy and its three-dimensional reconstruction.

We have developed a new confocal laser scanning microscope equipped with two galvanometer mirrors which swing the laser beam. With this set up we can observe large and fragile specimens. Using a focused laser beam as light source to minimize 'flare' and a pinhole in front of a photodetector to eliminate out-of-focus data, we could obtain a depth-discriminated fluorescence image. The scanning apparatus of our system can eliminate mechanical vibration and sweep widely, to obtain images at a low magnification. A thinly sectioned image with high resolution and high contrast could be obtained optically from an in situ thick specimen. We have called this technique 'microscopic tomography'. Combining the laser scanning microscope with the colour image analyser generated semi-automatically a three-dimensional picture of the biological material with information on its interior.

Animals↗