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Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 397 records · Page 22Linked to original sources
PubMed1995

A proteinous factor mediating intercellular communication during the transition of Dictyostelium cells from growth to differentiation.

In general, cell differentiation and proliferation are mutually exclusive. Transition of the cellular slime mold Dictyostelium discoideum from growth to differentiation is triggered mainly by a secreted factor(s) in addition to nutritional deprivation. To purify and identify the factor required for the growth/differentiation transition, a new assay system was designed. Under low-nutrient conditions, cells could grow to multiply, but never developed. The cellular development including aggregation, however, was induced by the addition of conditioned medium (CM) in which growing or starving Dictyostelium cells had been cultured. The CM inhibited the synthesis of nuclear DNA and induced the cells to acquire chemotactic competence to cAMP, thus suggesting the presence of a secreted factor(s) required for growth/differentiation transition in the CM. The active factor(s) in CM (referred to as CMF450; conditioned medium factor) was found to be sensitive to heat and have a large molecular size. The CMF450 was purified using FPLC through a gel filtration column, and was identified to be a proteinous macromolecule of Mr 450 kDa, which was mainly composed of 94 kDa, 79 kDa, and 49 kDa subunits under a native condition.

Amino Acid Sequence↗
PubMed1995

Primary biliary cirrhosis (PBC)-CREST (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly and telangiectasia) overlap syndrome complicated by Sjögren's syndrome and arthritis.

A 36-year-old woman with primary biliary cirrhosis (PBC)-CREST (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly and telangiectasia) overlap syndrome complicated by Sjögren's syndrome and arthritis is reported. She had suffered from Raynaud's phenomenon, sclerodactyly, morning stiffness, arthralgia and sicca symptoms since 34 years of age. She exhibited an increased level of alkaline phosphatase and hyperglobulinemia at 2.8 g/dl without any symptoms, and histological findings from the biopsy specimen of the liver were consistent with those of PBC. Her human leukocyte antigen (HLA) typing was DR8 homozygous.

Adult↗
PubMed1995

Hemolytic-uremic syndrome due to deoxycoformycin: a report of the second case.

A hypercalcemic patient with adult T-cell leukemia was treated with deoxycoformycin (DCF) in a dose of 5 mg/m2 daily for three days. Several days later, severe thrombocytopenia appeared abruptly and then microangiopathic hemolytic anemia ensued. Subsequently, renal failure and hypertension developed, and the patient died seven weeks after DCF therapy. Needle necropsy of the kidney showed glomerular damage including swelling of endothelial cells, mesangiolysis and segmental collapse. This is the second reported case of hemolytic-uremic syndrome due to DCF.

Fatal Outcome↗
PubMed1995

Primary intracranial epithelioid angiosarcoma--case report.

A 39-year-old male presented with an exceedingly rare primary intracranial epithelioid angiosarcoma in the right parietal lobe manifesting as weakness of the left hand. Neuroimaging revealed a well-defined intensely enhanced lesion in the right parietal lobe with peripheral cerebral edema. The tumor was grossly totally removed. Light microscopy of the surgical specimens revealed features typical of an epithelioid vascular tumor. The tumor cells showed intense positive immunohistochemical staining for cytokeratin and vimentin and focally positive staining for both Ulex europaeus agglutinin and anti-human endothelial cells, CD31. Tumor regrowth required two further operations. This progressive growth was consistent with an angiosarcoma. The tumor was diagnosed as an epithelioid angiosarcoma based on the histological and clinical characteristics. He became progressively obtunded and finally died. This is the first intracranial epithelioid angiosarcoma which expressed epithelial markers detectable by immunohistochemical methods.

Adult↗
PubMed1995

Acute revascularization for bihemispheric anterior cerebral artery thrombosis--case report.

A 65-year-old male presented with rapidly progressive paraparesis and akinetic mutism due to occlusion of the bihemispheric anterior cerebral artery (ACA). He was treated by intra-arterial thrombolytic therapy but reocclusion of the arteriosclerotic lesion occurred. Bilateral superficial temporal artery (STA)-ACA anastomoses achieved lasting neurological improvement. Bilateral STA-ACA anastomoses are quite effective to prevent ischemia of the bilateral ACA territories.

Aged↗
PubMed1995

Identification of differentially expressed mRNAs during neuronal differentiation of P19 embryonal carcinoma cells.

To understand the basic mechanisms underlying neuronal differentiation, we have attempted to isolate differentially expressed genes, which may play a key role in this complex process, from neuronal differentiating P19 embryonal carcinoma cells. RNA fingerprinting by the arbitrarily primed PCR (RAP) method was adapted to detect such differentially expressed genes during P19 neuronal differentiation. Using this method with some modifications, we successfully cloned seven cDNA fragments which were expressed differentially within the first 48 h after 1 microM retinoic acid (RA) treatment, which ultimately induces neuronal differentiation. Comparison of the partial nucleotide sequences of these clones with sequences in DNA databases indicated that one of these clones was identical to a region of the mouse Oct-3 gene, which has been shown to be dramatically repressed by RA. Two clones were highly homologous to the human profilinII and leucine-rich protein genes. The other four clones were not closely related to any sequences in the databases. Except for the Oct-3 gene, the other six genes isolated here have not been reported previously as RA-regulated genes. RAP is, thus, a promising method for identification of novel and potentially important genes which are differentially regulated during neuronal differentiation.

Animals↗
PubMed1995

[Primary intracranial malignant epidermoid--case report].

Intracranial malignant epidermoid is uncommon. We report a case of a 74-year-old woman with a primary intracranial malignant epidermoid in the parapontine region. The tumor was visualized as two components (a low-density benign prepontine lesion and a malignant enhanced cerebellopontine angle lesion) on CT scan. On MRI, the benign portion demonstrated low-signal intensity on T1 weighted images and markedly increased heterogeneous signal intensity on T2 weighted images, while the malignant portion showed iso-signal intensity on T1 weighted images that was markedly enhanced and heterogeneous signal intensity on T2 weighted images. Lack of contrast enhancement is a typical finding in benign epidermoid, although rim enhancement has been described in a few cases. In our patient, the contrast enhancement on CT scan in the otherwise typical epidermoid cyst suggested malignant degeneration. Using MR imaging, we could distinguish malignant epidermoid from benign epidermoid cyst more precisely.

Aged↗
PubMed1995

[Detection of hibernating myocardium in patients with myocardial infarction by low-dose dobutamine echocardiography: comparison with thallium-201 scintigraphy with reinjection].

The identification of hibernating myocardium is important for selecting patients who will benefit from coronary revascularization. The relationship between echocardiographic and radioisotopic markers of hibernating myocardium and postrevascularization recovery of myocardial function was investigated in 21 patients who underwent successful revascularization. Each patient underwent low-dose dobutamine stress echocardiography and thallium-201 (201Tl) scintigraphy with reinjection before revascularization. The presence of contractile reserve in dobutamine stress echocardiography and Tl uptake in 201Tl scintigraphy with reinjection were defined as markers of hibernating myocardium. Follow-up echocardiograms were evaluated for improved regional wall motion in all patients at a mean of 8.6 months after revascularization. Sensitivity, specificity, and positive and negative predictive values of low-dose dobutamine stress echocardiography for indicating recovery of function after revascularization were 75.0%, 77.8%, 81.8%, and 70.0%, respectively. Sensitivity, specificity, and positive and negative predictive values of 201Tl scintigraphy with reinjection for indicating recovery of function after revascularization were 91.7%, 55.6%, 73.3%, and 83.3%, respectively. There were no statistical differences between low-dose dobutamine echocardiography and 201Tl scintigraphy in predicting postrevascularization recovery of function patients with hibernating myocardium.

Aged↗
PubMed1995

[Assessment of coronary stenosis severity using a Doppler guide wire in vivo: is the continuity equation applicable to moderate to severe coronary artery stenosis?].

The usefulness of a Doppler guide wire was evaluated in the estimation of coronary stenosis severity in patients with moderate to severe coronary stenosis using the continuity equation. The maximal coronary flow velocities (V) proximal to the stenosis (p), at the stenosis (s), and distal to the stenosis (d) were measured using a Doppler guide wire (12-MHz, 0.018-in) in 12 patients with mild coronary stenosis (less than 50% diameter stenosis: group A) and 12 patients with moderate to severe coronary stenosis (more than 50% diameter stenosis: group B). Percent diameter stenosis (%DS) was calculated from Vp/Vs by: %DS = (1 - square root of Vp/Vs) x 100 (%) (Vp = the maximal velocity proximal to the stenosis; Vs = the peak velocity at the stenotic site) Percent DS was calculated from Vd/Vs by: %DS = (1 - square root of Vd/Vs) x 100 (%) (Vd = the peak velocity distal to the stenosis) Regression of Doppler-derived %DS from Vp/Vs compared to quantitative coronary angiographic % DS were: Group A: y = 0.83x + 3.0 (r = 0.79), Group B: y = 0.63x + 9.4 (r = 0.81), Overall: y = 0.63x + 9.6 (r = 0.91) Regression of Doppler-derived %DS from Vd/Vs compared to quantitative coronary angiographic %DS were: Group A: y = 0.98x - 1.0 (r = 0.81), Group B: y = 0.67x + 14.6 (r = 0.84), Overall: y = 0.79x + 7.6 (r = 0.91) The continuity equation method using a Doppler guide wire underestimates coronary stenosis severity in patients with moderate to severe coronary stenosis, although Doppler-derived %DS is correlated with angiographic %DS.

Blood Flow Velocity↗
PubMed1995

[Relationship between regional flow reserve supplied by the great saphenous vein graft and regional left ventricular wall motion: a Doppler guide wire study].

The relationship between regional flow reserve supplied by a great saphenous vein graft and myocardial infarction and anterior wall motion assessed by left ventriculography was studied in 28 patients with no stenosis in the great saphenous vein graft and the peripheral site of the recipient left anterior descending coronary arteries. The proximal segment to the anastomosis was totally or subtotally occluded. The resting graft blood flow velocity was measured using a Doppler guide wire, then 0.56 mg/kg of dipyridamole was injected for 4 minutes intravenously and the resultant increase in graft blood flow velocity was recorded. The regional flow reserve of the anterior wall supplied by great saphenous vein grafts in 11 patients with anterior myocardial infarction (MI group) was significantly lower than that in 17 patients without myocardial infarction (non-MI group) (1.5 +/- 0.3 vs 2.6 +/- 0.7, p < 0.01). The flow reserve supplied by great saphenous vein grafts in 11 patients with normal anterior wall motion was 2.8 +/- 0.7, 10 with hypokinesis 1.9 +/- 0.3, and with akinesis 1.3 +/- 0.3. Reduced anterior wall motion induced a significant decrease in the flow reserve of the anterior wall supplied by the great saphenous vein graft (p < 0.01). The anterior wall motion score of four segments assessed by left ventriculography showed a significant correlation with the flow reserve of the anterior wall supplied by the great saphenous vein graft (y = -0.24 x + 3.7, r = 0.75, p < 0.001). The results show infarcted myocardium was an important influence on coronary flow reserve.

Adult↗
PubMed1995

[Intravascular ultrasound scanning assessment of plaque distribution in the left anterior descending coronary artery just distal to the bifurcation].

Coronary plaque has a distinct spatial distribution with the peak incidence on the outer wall around the bifurcation of the left main coronary artery. Intravascular ultrasound scanning was used to evaluate the distribution of the plaque in the proximal site of the left anterior descending coronary artery in 16 patients. Coronary angiography showed the examined sites were normal in all patients. A cross-sectional coronary scan was recorded in the left anterior descending coronary artery just distal to the bifurcation using a 4.3 Fr, 30 MHz intravascular ultrasound catheter. The thickness of the plaque was measured at 0, 90, 180, and 270 degrees, where 0 degree indicates the left circumflex coronary artery branching direction. The scan was divided into four areas of 90 degrees and labeled 1 to 4 in the counterclockwise direction (site 1 was the left circumflex coronary artery branching direction). The thickness and area of the plaque were measured in each site. The percentage plaque fraction was calculated as (plaque area in each site)/(plaque area of all) x 100. In 15 (94%) of the 16 patients, images of crescent shaped plaques were obtained. The mean thicknesses of the plaque at sites 1-4 were 0.25 +/- 0.07 mm, 0.46 +/- 0.21 mm, 0.82 +/- 0.19 mm, and 0.42 +/- 0.23 mm, respectively. The mean percentage plaque fractions were 7.9 +/- 3.6% (site 1), 18.1 +/- 7.2% (site 2), 55.0 +/- 8.1% (site 3), 18.7 +/- 6.9% (site 4), respectively. In site 3, opposite to the left circumflex coronary artery branching, the thickness and percentage plaque fraction were significantly greater than the remaining three sites (p < 0.001). In vivo intravascular ultrasound scanning revealed that coronary plaque in angiographically normal left anterior descending coronary artery just distal to the bifurcation has a distinct distribution with a peak incidence opposite to the left circumflex coronary artery branching.

Aged↗
PubMed1995

[A study of acquisition time using compartment analysis with 99mTc-GSA liver scintigraphy].

99mTc-galactosyl human serum albumin (99mTc-GSA) is a newly developed receptor-binding agent specific for the asialoglycoprotein receptor, which resides exclusively on the plasma membrane of mammalian hepatocytes. Liver scintigraphy using 99mTc-GSA was performed on 13 patients with liver disease. Dynamic data were obtained by gamma camera during 40 min after the intravenous injection of 3 mg (185 MBq) of 99mTc-GSA. Heart and liver time activity curves with acquisition times of 40,30 and 20 min were created, and two different compartment analyses were examined. One was a nonlinear five-compartment model adopting the Michaelis-Menten type for the transfer of 99mTc-GSA from hepatic blood to receptor, and the other was a linear five-compartment model assuming a linear rate constant (P(2)*) for the transfer of 99mTc-GSA. The maximum removal rate obtained by the nonlinear model, P(2), was found to be independent of the change in acquisition time, while the maximum removal rate obtained by the linear model, P(2)*.Km, which was given by the product of P(2)* and the Michaelis constant Km, increased with shortening acquisition times from 40 to 20 min. For both models, the liver blood flow rate decreased with shortening acquisition time. The maximum removal rate and liver blood flow rate obtained by the linear model were significantly correlated with those obtained by the nonlinear model. It was concluded that linear model with an acquisition time of 20 min was applicable to liver scintigraphy with 99mTc-GSA.

Adolescent↗
PubMed1995

The effects of hemodialysis (HD) membranes on interleukin 1-beta (IL-1 beta) production from peripheral blood mononuclear cells (PBMC).

Dialysis-related symptoms are thought to be mediated by monocyte/macrophage-derived inflammatory cytokines, including interleukin 1-beta (IL-1 beta) and tumor necrosis factor alpha (TNF alpha). We investigated the effect of hemodialysis (HD) membranes on IL-1 beta production using cultured peripheral blood mononuclear cells (PBMC). PBMC were stimulated with lipopolysaccharide (LPS) and the cell content and production of IL-1 beta were measured by ELISA. PBMC from a single healthy donor incubated with 5% of untreated plasma, and we found that HD patients plasma enhanced IL-1 beta production less than normal control plasma. The plasma obtained from the venous side of HD patients 15 minutes after starting a single HD (15-min HD plasma) did not enhance IL-1 beta production as much as the plasma from the arterial side, either before or upon completion of a single HD (pre-HD plasma, post-HD plasma). We studied IL-1 beta productivity when pre-HD plasma (arterial side) and 15-min HD plasma (venous side) were added to autologous PBMC. The IL-1 beta production by PBMC was less when the 15-min HD plasma was added to PBMC as compared to when the pre-HD plasma was added. This reduction tended to be greater when a dialyzer membrane used was a large-pore type made of regenerated cellulose (RC) or polymethylmetacrylate (PMMA) than with a small-pore RC membrane. After HD for 2 weeks using a small-pore RC membrane, the same HD patient was then treated with a large-pore RC membrane. The PBMC IL-1 beta production level decreased with the use of the large-pore RC as compared to the case with the small-pore RC membranes. The present study suggests that large-pore dialyzer membranes remove middle molecules and low molecular weight proteins which enhance IL-1 beta production, and that this production may be regulated by some mechanism unrelated to complement activation.

Biocompatible Materials↗