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Biomedical subjects

T Yamaki

Publications and source records attributed to T Yamaki.

At least 19 recordsLinked to original sources
PubMed2001

Hemodynamic patterns of phosphatidylcholine hydroperoxide and hyaluronic acid during hepatic ischemia-reperfusion.

We investigated the hemodynamic pattern of serum hyaluronic acid (HA) and compared it with that of plasma phosphatidylcholine hydroperoxide (PCOOH) in terms of a convenient parameter of reperfusion injury. Using pig models, we designed two continuous ischemia groups, prepared by blockage of the blood flow at the hepatic hilum for 10 or 30 min. A discontinuous ischemia model was prepared by repeating the 10-min ischemia procedure, followed by 10 min of reperfusion, to a total ischemia period of 30 min. The PCOOH level started to increase just after reperfusion and reached the peak at 90 min, followed by a gradual decline after 6 h. The HA level increased rapidly in the continuous ischemia groups, starting immediately after ischemia onset until immediately before reperfusion, followed by a gradual decrease during up to 6 h of reperfusion. The HA levels in the three groups were almost normalized after 90 min of reperfusion, when the PCOOH level reached the peak. These results indicated that the plasma PCOOH level is a useful parameter for predicting the onset and progress of reperfusion injury in its initial stages.

Animals↗
PubMed2001

Ovarian fibrosarcoma producing multiple cytokines.

A case of ovarian fibrosarcoma producing multiple cytokines is presented. The tumor occurred in the left ovary of a Japanese woman with epigastralgia, remittent fever, leukocytosis and slight thrombocytosis with moderate increase of mast cells in bone marrow, but lack of hormonal abnormality. The resected tumor of the ovary was well encapsulated and it was composed of spindle-shaped tumor cells and scattered tubules with marked mast cell infiltration. The tumor recurred in the pelvic cavity 14 months later, accompanied by similar signs and symptoms as occurred with the primary tumor. Serum levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha were elevated. The recurrent tumor showed similar histological findings to those of the primary tumor, except for lack of tubules. Tumor cells revealed a focally positive immunoreaction for vimentin, IL-6 and TNF-alpha and alpha-inhibin. Reverse transcription-polymerase chain reaction using total RNA obtained from the recurrent tumor demonstrated mRNA expression of IL-6, IL-10, TNF-alpha and stem cell factor. This is a rare case of ovarian fibrosarcoma producing multiple cytokines, resulting in atypical clinical findings.

Cytokines↗
PubMed2001

Preliminary report of a new approach to sparing the greater saphenous vein for grafting: valvuloplasty combined with axial transposition of a competent tributary vein.

PURPOSE: To compare a new vessel-sparing technique combining valvuloplasty with axial transposition of a competent tributary vein versus single valvuloplasty for the treatment of greater saphenous vein (GSV) incompetence. METHODS: In 55 patients with GSV incompetence, 29 of 57 limbs were treated by angioscopic valvuloplasty of the subterminal valve alone, whereas the remaining 28 limbs underwent angioscopic valvuloplasty combined with axial transposition of a competent tributary vein identified preoperatively by duplex scanning. After angioscopic valvuloplasty in the latter group, the competent tributary vein was exposed and cut 1.5 cm distal to its insertion point on the GSV. The transected vein was anastomosed end to side to the GSV, which was ligated between the tributary insertion site and the anastomosis. Changes in venous hemodynamics, including venous filling index (VFI), ejection fraction (EF), and residual volume fraction (RVF), were analyzed by use of air plethysmography. RESULTS: In the 1-year follow-up, no venous thrombosis was detected in either group. In the valvuloplasty-only group, 22 (75.9%) limbs exhibited reflux in the proximal GSV; recurrent varicose veins were detected in 5 (17.2%) limbs. In contrast, only 2 (7.1%) limbs showed reflux in the valvuloplasty + transposition group. There were no significant differences in EF and RVF between the groups before or after the operation, although a significant difference was seen in VFI at 1 year (p = 0.005, Wilcoxon rank sum test). CONCLUSIONS: Valvuloplasty combined with tributary vein transposition gives a better result than valvuloplasty alone at 1 year. This new treatment option may be useful for both reducing the rate of varicose veins and sparing the GSV for grafting.

Adult↗
PubMed2001

[Clinical experience of intermittent administration of 5-FU and CDDP to patients with advanced and recurrent gastric cancer].

We administered 5-FU and CDDP (FP) intermittently to four patients with advanced and recurrent gastric cancer. A minor response (MR) and partial response (PR) were achieved in two of four patients who had evaluable lesions for this treatment, and few side effects were observed. Only one patient among six showed grade 2 leucocytopenia after 15 administrations of this chemotherapy, when she had attained a partial response in a lung metastasis. The other patients had no side effects such as bone marrow suppression or digestive symptoms. This intermittent FP treatment may be an effective and promising therapy with few side effects even for the patients with serious conditions.

Aged↗
PubMed2001

[Intermittent administration of 5-FU and isovorin to patients with advanced and recurrent colon cancer].

We attempted a new regimen of intermittent administration of 5-FU and low-dose Isovorin (F.I) to four patients with advanced and recurrent colon cancer. A partial response (PR) was achieved in two of four patients who had evaluable lesions for this treatment. We observed few side effects among these patients. Only one patient among four showed grade 1 neuropathy after two administrations of this chemotherapy. However, after a two-week pause in administration, the neuropathy disappeared and we could continue the therapy. This patient with multiple liver metastases achieved a partial response. Other patients had no side effects such as bone marrow suppression or digestive symptoms. This intermittent F.I treatment might be an effective and promising therapy with few side effects even for patients with poorer conditions.

Aged↗
PubMed2000

Predictive Values in the Progression of Chronic Venous Insufficiency Associated with Superficial Venous Incompetence.

The purpose of this study was to define predictive values in the progression of chronic venous insufficiency in patients with isolated superficial venous incompetence using duplex ultrasound and air plethysmography (APG). Five hundred eight legs in 371 patients with isolated superficial venous incompetence were included in this study. A color duplex scanner with a 5- to 10-MHz linear transducer was used to assess the distribution and the extent of venous reflux as well as the duration of reflux and the retrograde peak velocity at the saphenofemoral junction, greater saphenous vein in the thigh, and the saphenopopliteal junction. Venous reflux was considered to be present if the duration of reflux was greater than 0.5 s. The extent of greater saphenous vein is divided into 3 types. Type I: reflux from the groin to the ankle. Type II: reflux from the groin to the below-knee level. Type III: reflux from the groin to the above-knee level. Values obtained by APG were the venous volume (VV), venous filling index (VFI), ejection fraction (EF), and residual venous fraction (RVF). Between-group differences were analyzed using Wilcoxon's nonparametric rank sum test. Type I limbs had highest incidence of advanced chronic venous symptoms. Based on the duplex-derived duration of reflux and retrograde peak velocity in Type I limbs, there were three major groups: limbs with a retrograde peak velocity greater than 30 cm/s and a duration of reflux less than 3 s (group A), limbs with a retrograde peak velocity greater than 30 cm/s and a duration of reflux greater than 3 s (group B) and limbs with a retrograde peak velocity of less than 30 cm/s and a duration of reflux greater than 3 s (group C). Most of the class 2 and class 3 limbs belonged to Group C, whereas most of the class 4 limbs and all of the class 5 and class 6 limbs belonged to group A and group B. APG-derived VFI had significantly higher values in group A and group B compared with group C (P < 0.002). Peak velocity greater than 30 cm/s had a high positive predictive value of 75.0% with a sensitivity of 91.1%. Although duplex-derived duration of reflux is widely used to assess venous reflux, our data suggest that the peak velocity is a better predictor of the progression of chronic venous insufficiency and that it correlates well with the severity of the clinical manifestation in cases with isolated superficial venous insufficiency.

Journal Article↗
PubMed2000

Abnormal pigmentation of schwannoma attributed to excess production of neuromelanin-like pigment.

Five cases of non-melanotic pigmented schwannoma with excess accumulation of neuromelanin are presented. The tumors were composed basically of spindle or fusiform tumor cells, compatible with those of classical schwannoma, together with varying numbers of tumor cells containing various amounts of light brown or grayish pigment. Fontana-Masson stain demonstrated argentaffin granules in some tumor cells of each tumor and bleaching with potassium permanganate abolished argentaffin reaction. Ultrastructural examination demonstrated the granules contained fine particles with heterogeneous density, occasionally together with coarse granular materials or amorphous high-density areas, indicating lysosome or autophagosome. Neither typical melanosomes nor neurosecretory granules were detected. In immunohistochemistry, neurogenic markers as well as CD68 were expressed in most tumor cells in each case and various numbers of tumor cells were positive for Leu7 and CD34. Lysozyme was also frequently positive in tumor cells, especially in granular cells. HMB45 was not expressed in any of the cases. These findings indicate that these cases are schwannomas with abnormal accumulation of neuromelanin-like pigment.

Aged↗
PubMed2000

Clear cell sarcoma arising in the transverse colon.

A case of clear cell sarcoma (CCS) arising in the transverse colon is presented. The tumor consisted of sheets or small nests of epithelioid malignant cells possessing pleomorphic nuclei with one or more prominent nucleoli and ample clear or slightly eosinophilic cytoplasm. Some of the tumor cells contained various amounts of melanin pigments that were confirmed by histochemical and ultrastructural examinations. Immunohistochemical examination showed a positive immunoreactivity for HMB45 and S-100 protein. A metastatic nodule, which was found 9 months after surgery, showed similar histological findings to those of the primary one but lacked melanin pigments. Reverse transcriptase- polymerase chain reaction using total ribonucleic acid obtained from metastatic nodule demonstrated the presence of EWS-ATF-1 fusion gene. Based on these findings, the present case tumor is a CCS of the colon.

Aged↗
PubMed2000

Quantitative assessment of superficial venous insufficiency using duplex ultrasound and air plethysmography.

OBJECTIVE: The purpose of this study was to quantitatively evaluate venous reflux in limbs with isolated superficial venous insufficiency using color duplex ultrasound. In addition, air plethysmography (APG) was used to investigate possible correlations of duplex-derived peak velocity, duration of reflux, and CEAP classification. METHODS: One hundred and forty-six legs in 109 patients with isolated superficial venous insufficiency refluxing throughout the length of the limb were selected for prospective study by duplex scan. Reflux was defined as duration of reflux >/=0. 5 seconds. This study was conducted in a university hospital. Venous reflux was evaluated with the patients standing, by the duration of reflux, retrograde peak velocity, reflux volume at the saphenofemoral and saphenopopliteal junction as well as the greater saphenous vein in the thigh. Values obtained by APG were the venous volume (VV), venous filling index (VFI), ejection fraction (EF), and residual venous fraction (RVF). A significant difference was defined as P <.05. Three groups of limbs were analyzed: group A limbs with a retrograde peak velocity greater than 30 cm/second and a duration of reflux of less than 3 seconds; group B with a retrograde peak velocity >/=30 cm/second and a duration of more than 3 seconds; and group C with a retrograde peak velocity of less than 30 cm/second and a duration of reflux of more than 3 seconds. RESULTS: Groups A and B contained 103 limbs, and 24 of these were in CEAP class 5 and 6. Group C contained 43 limbs, none of which were in class 5 or 6. APG demonstrated significant reflux in group A, and VFI was significantly higher compared to group B and group C (P =.0007 and P =.0064, respectively). A significant correlation was demonstrated between peak retrograde reflux velocity and VFI. CONCLUSIONS: Severe chronic venous insufficiency is found in limbs with high reflux velocity (greater than 30 cm/second) and the duration of reflux does not correlate with severe chronic insufficiency.

Adult↗
PubMed2000

Color duplex-guided sclerotherapy for the treatment of venous malformations.

BACKGROUND: Although surgical extirpation is the standard method for the treatment of vascular malformations, this procedure often leads to loss of motor function, nerve damage, and massive bleeding if the excision is extensive. Sclerotherapy is an alternative method of treatment for venous malformations. OBJECTIVE: This study was conducted to assess the effect of color duplex ultrasound-guided sclerotherapy on venous malformations and the coagulability induced by sclerosing solution. METHODS: Twenty-eight patients with venous malformations underwent percutaneous sclerotherapy by direct puncture under duplex ultrasound guidance. Intravenous catheters were inserted into duplex ultrasound-confirmed venous spaces and fine plastic tubing filled with normal saline was attached to the needle. When the needle tip was observed to pierce the vein wall, aspiration of the blood confirmed its intraluminal position. The mean volume of 3.6 ml of 3% polidocanol was injected. Subfascial ligation of the lateral marginal venous collector was performed in patients with Klippel-Trenaunay syndrome. D-dimer (DD) and thrombin-antithrombin III (TAT) were measured preoperatively and on the first and fifth postoperative days. RESULTS: The head and neck, which was the most common site of venous malformations were involved in 57% of the patients. Venous malformations disappeared in 44% of the patients and decreased in 28%. Localized pain was the most common complication, occuring in 82% of the patients. Sclerotherapy for venous malformations produced significant swelling in 75% of the patients, which required 5-7 days to subside. Significant differences were detected in both DD and TAT concentrations on the first and fifth postoperative days. CONCLUSIONS: Color duplex-guided sclerotherapy was effective in 82% of the patients. This procedure prevents intra-arterial injection accidents. Although patients with venous malformations showed greater coagulability, no serious thrombotic sequelae were found.

Adolescent↗
PubMed2000

Development of a new inhibitor of glucosylceramide synthase.

Analogs of the potent inhibitor of glucosylceramide (GlcCer) synthase, D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4), based on substitutions in the palmitoyl group were made by means of a stereo-selective synthetic method in order to elucidate the role of the hydrophobic portion in both the inhibitory action toward the enzyme and the biological effects. While P4 strongly inhibited GlcCer synthase with an IC(50) of 0.5 microM in vitro, it also inhibited cell growth by 50% at the concentration of 7 microM. The shorter N-acyl chain analogs including decanoyl, octanoyl, and hexanoyl groups showed similar IC(50) values for GlcCer synthase (around 2 microM) but the hexanoyl analog exhibited only a slight inhibitory effect on cell growth, showing the dissociation between GlcCer depletion and cell growth. Several compounds which exhibit similar hydrophobicity to the hexanoyl analog of P4 were subsequently designed. We found that D-threo-1-phenyl-2-benzyloxycarbonylamino-3-pyrrolidino-1-pr opanol (PBPP) was a most potent inhibitor, showing an IC50 of 0.3 microM. In cultured cells, PBPP was able to deplete glycosphingolipids without affecting cell growth or the ceramide level.

Animals↗
PubMed2000

False localization of rupture site in patients with multiple cerebral aneurysms and subarachnoid hemorrhage.

OBJECTIVE: Patients with subarachnoid hemorrhage and multiple intracranial aneurysms present a unique challenge to the neurosurgeon. Unless all aneurysms can be clipped through a single craniotomy, the surgeon must accurately determine which aneurysm has ruptured. Misjudgment may result in disastrous postoperative rebleeding from the untreated but true ruptured lesion. We assessed the risk of false localization of the rupture site and subsequent rebleeding and documented the problems in predicting the true rupture site when patients have multiple intracranial aneurysms. METHOD: We reviewed the records of a consecutive series of 93 patients treated over a period of 12 years who presented with their first subarachnoid hemorrhage and who had multiple intracranial aneurysms. The rupture site was determined on the basis of computed tomographic and angiographic findings, and the supposed ruptured aneurysm was clipped within 2 days of hemorrhage in each patient. Additional aneurysms that could not be accessed in the same surgical session were operated on at a later stage. All patients' records were reviewed, and all computed tomographic scans and angiograms, including repeat studies performed in some patients, were retrospectively reevaluated by the authors, who had no knowledge of the patients' clinical information. RESULTS: The location of the aneurysm that ruptured was verified at the time of surgery or during the autopsy in 76 patients (82%). The aneurysm that ruptured was the one predicted as ruptured by the surgeon before surgery in 69 patients (91%) and in retrospect in 72 patients (95%). Five of the 6 patients in whom the ruptured aneurysm was not correctly identified were thought to have only a single aneurysm. Four patients rebled after surgery, and 2 patients died as a result of the rebleeding. CONCLUSION: In the reported series, the most common cause of rebleeding soon after aneurysm surgery was failure to obliterate the ruptured aneurysm, usually because it was missed on the initial angiogram. The results support not only meticulous radiological investigation of all intracranial arteries before surgery but also thorough surgical inspection of the target aneurysm in all cases of subarachnoid hemorrhage even after one candidate lesion has been discovered.

Adult↗
PubMed2000

[Diagnosis of brain tumor with proton MR spectroscopy--the quantification of gliomas compared with normal brain].

We conducted quantification of proton MR spectroscopy (MRS) using water signal as an internal standard, in order to quantify the concentrations of metabolites in normal adult brains and in gliomas in vivo. Single-voxel spectra were acquired using a point-resolved spectroscopic (PRESS) pulse sequence as part of the Probe. P spectroscopy package on a GE Signa Horizon Hispeed LX1.5T scanner (TR/TE/Ave = 3000 msec/30 msec/64). The volume of interest (VOI) varied from 15.0 x 15.0 x 15.0 mm3 to 20.0 x 20.0 x 20.0 mm3 for the brain. The present study included 26 healthy volunteers and 12 patients with gliomas, whose diagnoses were verified by histologic examination. The calculated concentrations of N-acetyl-aspartate (NAA), creatine (Cre) and choline (Cho) in normal hemispheric white matter were 23.66 +/- 1.94 mM (mean +/- SD), 12.97 +/- 1.44 mM, and 4.38 +/- 0.60 mM, respectively. We found they were not necessarily uniform in different parts of the brain, for example, in the pons and basal ganglia. The concentrations of NAA and Cre decreased in all gliomas (p < 0.001). Cho concentration also decreased in the glioma (p < 0.005). The NAA/Cre, NAA/Cho, and Cre/Cho ratios can distinguish normal brain from gliomas, and NAA/Cho ratio can distinguish low-grade astrocytoma from the high-grade group. The results indicate that this noninvasive method offers reasonable estimation of metabolite concentrations in the brain in vivo and therefore is useful in diagnoses of gliomas.

Adult↗
PubMed1999

Covalent structures of BmK AS and BmK AS-1, two novel bioactive polypeptides purified from Chinese scorpion Buthus martensi Karsch.

Complete amino acid sequences of two novel bioactive polypeptides, each containing 66 amino acid residues, BmK AS and BmK AS-1 purified from the venom of Chinese scorpion Buthus martensi Karsch, have been determined by Edman sequencing and mass spectrometry on native proteins, reduced and S-carboxymethylated proteins and their peptides obtained after cleavage with proteolytic enzymes. Sequence analysis showed 86.4% structural identity between BmK AS and BmK AS-1 and also a high sequence similarity between BmK ASs and AaH IT4, a unique anti-insect toxin and a ligand of Na+ channels obtained from Sahara scorpion A. australis Hector, but poor sequence homology between BmK ASs and those of the known alpha-, beta-type and long-chain insect-selective type scorpion neurotoxins. The positions of four disulfide bridges in BmK AS-1 were established as Cys-12 and Cys-62, Cys-16 and Cys-37, Cys-23 and Cys-44, and Cys-27 and Cys-46, which are the same as those in alpha- and beta-scorpion neurotoxins. These results suggest that BmK ASs and AaH IT4 may form a new group sharing similar structural and functional properties in the family of scorpion neurotoxic polypeptides.

Amino Acid Sequence↗
PubMed1999

Yolk sac tumor of the stomach with an adenocarcinomatous component: a case report with immunohistochemical analysis.

A 56-year-old male treated for a gastric yolk sac tumor with an adenocarcinomatous component is described. A mixed area of reticular and glandular neoplastic components was morphologically identified in this tumor. Immunohistochemically, the yolk sac tumor expressed alpha-fetoprotein (AFP), placental alkaline phosphatase (PLAP), and cytokeratin, but was negative for carcinoembryonic antigen (CEA). The adenocarcinoma was positive for CEA and cytokeratin, partially positive for PLAP, and negative for AFP. In the mixed area, the tumor cells were positive for cytokeratin, weakly expressed AFP and PLAP, and sporadically stained for CEA both in the reticular and glandular components. This area was identified as a transitional area of the yolk sac tumor and adenocarcinoma. These findings demonstrate that the yolk sac and adenocarcinomatous components are closely related. It also suggests that the tumor arose from multipotential neoplastic mucosal epithelial cells with both yolk sac and gastric mucosal phenotypes.

Adenocarcinoma↗
PubMed1999

Acute massive pulmonary embolism following high ligation combined with compression sclerotherapy for varicose veins report of a case.

A case of acute pulmonary embolism following high ligation and compression sclerotherapy for varicose veins is reported. A 54-year-old women developed superficial varicosities and stasis pigmentation on her left leg 1 year prior to her first visit to hospital. No deep vein thrombosis was detected by ascending phlebography performed 3 months prior to operation. High ligation combined with compression sclerotherapy was performed for the varicose veins. One day after treatment, the patient complained of chest pain and discomfort, and then collapsed. Perfusion scintigraphy revealed multiple embolisms in the bilateral lungs. The patient recovered after aggressive anticoagulant and thrombolytic therapy. Although pulmonary embolism is a rare complication of sclerotherapy, it is potentially one of the most serious.

Acute Disease↗