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T Maeda

Publications and source records attributed to T Maeda.

At least 523 records · Page 29Linked to original sources
PubMed1997

[Evaluation of cerebral ischemia with metabolic image by using 3D-CSI--comparing with SPECT and PET].

MR spectroscopy(MRS) is a powerful method to evaluate brain metabolism directly and non-invasively. We developed 3D-CSI method as a multi-voxel MRS. It has some advantages or single-voxel MRS; 1) spectra in many voxels can be acquired simultaneously 2) Mapping of metabolites can be acquired 3) A small size voxel can be obtained. It make it possible to evaluate the change of NAA in wide area. In case of cerebral ischemia, we found the tendency that NAA decreases in fatal damage area and is normal in recoverable damage area. Therefore, we suppose that NAA could be a indicator of viability of neuron. It is necessary to coordinate the data from MRI/ MRS and PET/SPECT for analyzing the pathophysiology of cerebral ischemia.

Amphetamines↗
PubMed1997

Fine structure of crest synapses in the locus coeruleus of the Japanese macaque (Macaca fuscata), with special reference to noradrenergic neurons.

The crest synapse and its related structures in the locus coeruleus (LC) of the Japanese monkey, Macaca fuscata, were electronmicroscopically studied using noradrenaline (NA) immunohistochemistry and tannic acid fixation. About 20% to 25% of the noradrenergic input to the LC terminated at noradrenergic neurons. About 1/3 of these NA-NA connections formed crest synapses, although conversely, NA-immunoreactive (IR) terminals were found in 10% of all terminals forming crest synapses. The crests showing parent dendrites were clearly NA-IR, and definite nonNA-IR dendritic crests were not found. Thus, crest synapses were present almost exclusively on noradrenergic neurons in the monkey LC. The crests were composed of parallel postsynaptic membranes 120 to 130 nm in width and 550 to 610 nm in length, accompanied by a thick-dense material of cytoplasm, and regular single rows of electron dense subjunctional bodies which were arranged in approximately 8 transverse rows. A maximum of 12 electron-dense subjunctional bodies per row were counted in the middle section, and decreased bilaterally in number. The crests further contacted with the dendritic spiny processes of neighboring NA-IR neurons. These results suggest that the crest synapse is an evolved and powerful synaptic structure which makes it possible for noradrenergic neurons in the LC to fire simultaneously at a slow and constant frequency depending on the behavioral state.

Animals↗
PubMed1997

Analysis of prognostic risk factors in hepatic resection for metastatic colorectal carcinoma with special reference to the surgical margin.

BACKGROUND: Liver resection for metastatic colorectal cancer has been established. Nevertheless, it is still controversial whether the surgical margin from the tumour edge to the cut surface of the liver is a significant prognostic factor in hepatic resection for colorectal metastatic liver cancer. METHODS: To clarify the prognostic risk factors in hepatic resection for colorectal metastasis, univariate and multivariate analyses were performed. Between April 1985 and April 1995, 31 patients underwent curative hepatic resection for metastatic colorectal cancer. The clinical and pathological factors were examined retrospectively. RESULTS: Overall 1-, 3- and 5-year survival rates of the patients were 92, 42 and 39 per cent respectively. Pathological study of 16 resected specimens with a solitary liver tumour revealed hepatic vein invasion by cancer cells in two of 16 cases, portal vein invasion in three, microsatellite lesions in two and biliary tract invasion in six cases. In resected specimens with a solitary tumour measuring less than 4 cm in diameter, one of these factors was observed in only two of nine cases, whereas in specimens with a solitary tumour measuring more than 4 cm in diameter, these factors were observed in six of seven patients (P < 0.05). The distance from the tumour edge to the intrahepatic invasion was less than 10 mm. With univariate analysis, tumour size of 4 cm or more in diameter, an interval of 6 months or less between colorectal and hepatic resection, four or more gross tumours, bilobar involvement and a resection margin from the tumour of less than 10 mm were found to be significant factors indicating a poor prognosis. Cox's proportional hazards model identified a tumour of 4 cm or more in diameter and a resection margin from the tumour of less than 10 mm as poor prognostic factors (P < 0.05). CONCLUSION: In treating metastatic colorectal cancer to the liver, the surgical margin should be more than 10 mm because occult intrahepatic invasion was always found to be located within 10 mm from the edge of the tumour.

Adult↗
PubMed1997

[Experimental bilateral focus model of complex partial seizure: clinical, electrophysiological and pathological studies].

Stereotactic surgery was performed in Wistar rats and stainless steel injection chemitrode were inserted in bilateral amygdala (AM). Stainless steel screws were placed on the dura over bilateral motor cortex (Cx). One week after the surgery, rats were placed in the recording chamber. Kainic acid (KA) injection was performed into the left AM and focal AM seizure status was induced. Seizures evolved into limbic seizure status during 3 days. Seven days after the first KA injection, KA was injected into the right AM. The limbic seizure status was elicited again, however, these seizures subsided within 3 days. About 3 week after the first KA injection, spontaneous limbic seizures developed. Three ictal EEG patterns were seen (1) Bilateral independent seizures, (2) Synchronous ictal discharge over the bilateral AM, and (3) Switch of lateralized ictal activity from one to the other AM. The histological study demonstrated bilateral hippocampal cell loss and hippocampal atrophy. These changes are very similar to those observed in human intractable complex partial seizures with bilateral mesial temporal focus. The result suggests that this model will be a good tool in order to resolve intractability of complex partial seizure in patients with bilateral temporal focus.

Animals↗
PubMed1997

[On intra-familial clinical diversities of a familial amyotrophic lateral sclerosis with a point mutation of Cu/Zn superoxide dismutase (Asn 86-Ser].

In a familial amyotrophic lateral sclerosis (FALS) with SOD-1 mutation (Asn 86-Ser), there were intra-familial clinical diversities. The proband, a daughter patient, shows a mild clinical course of 16 years. Her father died of respiratory failure in 3 years. His initial symptom was weakness of upper extremity. The daughter's first symptom was that of lower extremities. Her respiratory-assist started after 9 years from the onset. She is alive under whole-day respiratory assist while she had been taking nutrients per os for 15 years. Her abilities of swallowing remain, even more dependent of tube-feeding (15 years after the onset). The fact of the presence of intra-familial clinical varieties with SOD-1 mutation in FALS suggests that the mutation is not an exclusive factor to determine the clinical phenotype, age of the onset and rapidity of illness of FALS associated with SOD-1 mutation. We collect reports of FALS with SOD-1 mutation which have similar diversities of intra-familial clinical manifestations as our family. Varieties of intra-familial clinical manifestations of motor neuron disease are shown in 9 families with SOD-1 mutation. The genetic error appears to have a limit, and is not a exclusive cause of FALS. However, we should not underestimate the significance of the discovery of a gene, since it might offer a clue to still unanswered riddle of ALS pathogenesis.

Amyotrophic Lateral Sclerosis↗
PubMed1997

[Re-rupture of intracranial aneurysm caused by insertion of an intraventricular drainage tube].

A 42-year-old man was admitted to our hospital with subarachnoid hemorrhage, requiring the clipping of an intracranial aneurysm and removal of intracranial hematoma. Anesthesia was induced with thiamylal and maintained with oxygen-nitrous oxide-isoflurane. Trimethaphan was administered continuously and his systolic blood pressure was stably maintained between 100-110 mmHg. Seven minutes after insertion of an intraventricular drainage tube through the dura, his blood pressure increased to 146/76 mmHg. By transdural echogram, re-rupture of the aneurysm was confirmed, and after 6 minutes, a fresh intracranial hematoma was observed. The decrease of intracranial pressure following insertion of the intraventricular drainage tube or the stimulation by several intraventricular punctures seems to have caused re-rupture of the aneurysm. When hemodynamic change is observed without obvious cause in a patient with subarachnoid hemorrhage, it is important to speculate that a re-rupture of the aneurysm has occurred, and to treat the problem accordingly.

Adult↗
PubMed1997

Ultrastructure of the synovial sensory peptidergic fibers is distinctively altered in different phases of adjuvant induced arthritis in rats: ultramorphological characterization combined with morphometric and immunohistochemical study for substance P, calcitonin gene related peptide, and protein gene product 9.5.

OBJECTIVE: To characterize sequential ultramorphological changes in synovial sensory peptidergic fibers in different phases of adjuvant induced arthritis. METHODS: Topographically defined regions of the tarsal joints from arthritic rats were evaluated 7, 10, 14, and 21 days after inoculation with Freund's adjuvant. Peptidergic fibers were identified by high resolution video microscope, then fibers containing calcitonin gene related peptide (CGRP) were visualized by electron microscopy. Morphometric quantification of synovial fibers immunohistochemically stained for CGRP, substance P (SP), and protein gene product 9.5 (PGP 9.5) was done at this time. RESULTS: The control synovial lining contained numerous ramified axon terminals, whereas the sublining contained mostly nerve fiber bundles, except for axon terminals visible around the blood vessels. In arthritis, on Day 14, there were few immunoreactive nerve fibers and terminals. Instead, electron microscopy disclosed numerous activated and/or degenerated axons [CGRP: 2973 +/- 345 vs 495 +/- 288; SP: 657 +/- 344 vs 199 +/- 60; PGP 9.5: 4473 +/- 944 vs 886 +/- 299, all p < 0.05 (units: microm/mm2)]. On Day 21 CGRP and PGP 9.5 immunoreactive fibers were numerous again (4892 +/- 551 and 3613 +/- 1350, respectively), but SP immunoreactive nerve fibers did not seem to regenerate (126 +/- 44). Regenerating nerve fibers had a distinctive ultrastructure and they were always seen in association to Schwann cells. CONCLUSION: The healthy synovial lining is innervated by peptidergic nerve terminals. During the inflammatory phase of arthritis neuropeptides are locally released due to stimulation and degeneration of the axons. The apparently unaffected Schwann cells seem to play a pivotal role in subsequent regeneration of peptidergic axons. However, the ultrastructure and the neuropeptide content (and probably the function) of the regenerating axons are different from those of the normal synovial nerve fibers.

Animals↗
PubMed1997

[Arterial infusion chemotherapy in pelvic space for advanced rectal cancer].

Three rectal cancer patients were treated with arterial infusion chemotherapy through the internal iliac artery. Two patients with pelvic recurrences unresectable after APRA were treated with intensive chemotherapy and the other patient with neoadjuvant chemotherapy. In all cases, 5-FU (500 mg/ body/day) was administered continuously for 5 days or 14 days. We attempted three methods for this procedure which were a bilateral catheterization to the internal iliac artery, a single catheterization with an embolization to the other internal iliac artery and a single catheterization without the embolization. As the result of this treatment, in the resected specimen with neoadjuvant case, histological necrosis was found in 50% in the main tumor and the metastatic lymph nodes. One patient with pelvic recurrence showed a partial response in CT imaging, but died one year later of the recurrence around the external iliac artery. The other patient with pelvic recurrence treated with the bilateral catheterization had no efficacy on CT imaging, but his CEA level has decreased at present. It was concluded that arterial infusion chemotherapy was effective for advanced rectal cancer and the pelvic recurrences. However, the efficacy of this treatment is limited to the area to which the drugs are delivered. Thus, it is important that the method and the location of the catheterization are determined adequately for each case.

Antidotes↗
PubMed1997

[Thrombocytopenia associated with sodium polystyrene sulfonate].

A 84-year-old man was admitted with diabetes mellitus, hypertension and chronic renal failure in September 1994. In October 1995, his renal function gradually worsened with hyperkalemia. Sodium polystyrene sulfonate (Kayexalate) was administered orally for the treatment of hyperkalemia. However, after 7 days from the start of Kayexalate therapy, thrombocytopenia progressed gradually, and 12 days later the initial platelet count of 20.7 x 10(4)/microliter decreased to 8.6 x 10(4)/microliter. This thrombocytopenia rapidly improved after cessation of Kayexalate administration. In December 1995, readministration of Kayexalate for the treatment of hyperkalemia induced thrombocytopenia again. Bone marrow aspiration biopsy revealed normal counts of nucleated cells and megakaryocytes with no increase in blasts. No other disorders which cause thrombocytopenia were seen in this patient. The complication of thrombocytopenia associated with Kayexalate has not been reported. This is the first reported case of thrombocytopenia caused by Kayexalate administration.

Aged↗
PubMed1997

[A case of primary mucinous adenocarcinoma of jejunum].

A 73-year old woman consulted our hospital for consciousness disorder and was hospitalized under a diagnosis of cerebral infarction. On admission, retention of a large volume of ascites was noted. There were also marked increases in tumor markers. Serum CEA, CA19-9 and CA125 levels were 871.9 ng/ml, 1048.2U/ml, and 444.7U/ml, respectively. Cytological examination of the ascites showed class V. Abdominal CT showed a mass measuring 4 cm in diameter and dilatation of the small intestinal tract. During detailed examination, she developed ileus. Fluoroscopy through the lung tube suggested a small intestinal tumor. Laparotomy was performed to relieve ileus. In the abdominal cavity, the greater omentum formed a mass due to dissemination. Tumor was found in the jejunum approximately 60 cm from Treitz's ligament toward the anal side. Omentectomy and partial jejunectomy were performed. Macroscopic findings showed tumor protruding from the mucosal surface. Histological diagnosis was mucinous adenocarcinoma. Primary small intestinal cancer is very rare. In particular, only one case of mucinous adenocarcinoma of the small intestine was reported in Japan. We reported the second case in Japan with a review of the literature.

Adenocarcinoma, Mucinous↗
PubMed1996

Three-dimensional structures of the amyloid beta peptide (25-35) in membrane-mimicking environment.

The three-dimensional structure of amyloid beta peptide (25-35), which has neurotoxic activity, in lithium dodecyl sulfate micelles was determined by two-dimensional 1H NMR spectroscopy with simulated annealing calculations. A total of 20 converged amyloid beta peptide structures were obtained on the basis of 110 experimental constraints, including 106 distance constraints reduced from the nuclear Overhauser effect (NOE) connectivities and four torsion angle (phi) constraints. The atomic root mean square difference about averaged coordinates is 1.04 +/- 0.25 A for the backbone atoms (N, C alpha, C) and 1.39 +/- 0.27 A for all heavy atoms of the entire peptide. The molecular structure of amyloid beta peptide in membrane-mimicking environment is composed of a short alpha helix in the C terminal position. The three residues from the N-terminus are disordered, but the remaining eight C-terminal residues are well-ordered, which is supported by the RMSD values of the C-terminal region, Lys28-Leu34. In this region, the RMS differences from averaged coordinates are 0.26 +/- 0.11 A for the backbone atoms (N, C alpha, C) and 0.77 +/- 0.21 A for all heavy atoms, which is very low compared with those for the entire peptide. The four amino acid residues from the N-terminus are hydrophilic and the other seven amino acid residues in C-terminus are hydrophobic. So, our results show that the C-terminal region of amyloid beta peptide (25-35) is buried in the membrane and assumes alpha-helical structure, whereas the N-terminal region is exposed to the solvent with a flexible structure. This structure is very similar to membrane-mediated structure of substance P previously reported. The three-dimensional structure of a non-neurotoxic mutant of amyloid beta peptide (25-35), where Asn27 is replaced by Ala, in lithium dodecyl sulfate micelles was also determined. The structure is similar to that of the wild type amyloid beta peptide (25-35) in the C-terminal region, but the N-terminal flexible region is different. The structural comparison of amyloid beta peptide (25-35), its non-neurotoxic mutant and substance P gives a structural basis to understand the mechanism of neurotoxicity caused by amyloid beta peptide.

Amino Acid Sequence↗
PubMed1996

Differential neurotoxicity induced by L-DOPA and dopamine in cultured striatal neurons.

The neurotoxicity of L-DOPA and dopamine (DA) on striatal neurons was examined by using primary cultures of rat striatum. Exposure to L-DOPA and DA at concentrations of 30-300 microM induced dose-dependent cell death in both younger cultures (3 days in culture, 3 DIC) and elder cultures (10 days in culture, 10 DIC). The cytotoxicity of L-DOPA and DA was also dependent on the exposure time (6-24 h). Ascorbic acid (200 microM) inhibited both L-DOPA- and DA-induced cytotoxicity in 3 DIC cultures, whereas it provided significant protection against DA- but not L-DOPA-induced cytotoxicity in 10 DIC cultures. The L-DOPA cytotoxicity in 10 DIC cultures was prevented by a non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and by an NMDA receptor antagonist, MK-801. Neither antagonist prevented DA cytotoxicity. D-DOPA did not affect the viability of 10 DIC cultures, though it elicited marked toxicity in 3 DIC cultures. These results suggest that there are two components in the mechanisms that mediate the L-DOPA neurotoxicity on striatal neurons: one is autoxidation-relevant and the other is autoxidation-irrelevant. With respect to the latter, glutamate receptor stimulation may be involved. In contrast, autoxidation plays an important role in DA neurotoxicity.

Animals↗
PubMed1996

Demonstration of a new dopamine-containing cell group in the primate rostral telencephalon.

The presence of dopaminergic neurons in the rostral forebrain has long been uncertain though the existence of tyrosine-hydroxylase (TH)-containing cells has been known in the region. Using an antibody to dopamine (DA), we demonstrated neurons immunoreactive (ir) to DA in the rostroventral striatum of the Japanese monkey (Macaca fuscata). The DA-ir cells were found at the ventral margin of the rostral part of the caudate nucleus, at the ventral margin of the rostral part of the nucleus accumbens, in the olfactory tubercle, and along the lateral margin of the putamen. These cells were intensely stained, small in size, and fusiform or ovoid in shape, and had one or two short processes. DA-ir cells were far smaller in number than TH-ir ones. The primates may possess a unique dopaminergic system in the rostral telencephalon.

Animals↗
PubMed1996

Inhibition of peritoneal dissemination of colon carcinoma in syngeneic mice immunized with interleukin-2-producing cells.

We have examined the antitumor effect of murine colon carcinoma cells engineered to produce human interleukin-2 (IL-2) in syngeneic mice. Subcutaneous inoculation of retrovirally-transduced cells with IL-2 gene formed small tumors, but they became regressed spontaneously. Consequently, the inoculated mice showed prolonged survival. Histological examination of the tumors derived from IL-2-producers revealed predominant infiltration of macrophages around tumor necrotic masses. Thus, inoculation of IL-2-producing cells could protect the mice from subsequent subcutaneous or intraperitoneal challenges with wild-type cells, suggesting the induction of acquired immunity due to the effect of tumor vaccination.

Animals↗
PubMed1996

Des-gamma-carboxy prothrombin and alpha-fetoprotein positive status as a new prognostic indicator after hepatic resection for hepatocellular carcinoma.

BACKGROUND: The aim of this study was to elucidate the usefulness of measuring the positive status of both des-gamma-carboxy prothrombin (DCP) and alpha-fetoprotein (AFP) preoperatively as a new prognostic indicator of hepatocellular carcinoma (HCC). METHODS: One hundred forty-seven patients who underwent curative hepatic resection for primary HCC were studied. The definitions of DCP and AFP positivity were: positive DCP > 0.1 AU/ml, and positive AFP > 50 ng/ml. The patients were classified into four groups according to their levels of positivity for DCP and/or AFP: Group 1 (n = 59), negative levels of both DCP and AFP; Group 2 (n = 28), negative DCP and positive AFP levels; Group 3 (n = 31), positive DCP and negative AFP levels; and Group 4 (n = 29), positive levels of both DCP and AFP. RESULTS: Patient survival and disease free survival in Group 4 were the worst among the four groups. By multivariate analysis, using Cox proportional hazards model, both the DCP- and AFP-positive status (in combination) and poorly differentiated histology were independent factors of poor prognosis for patient survival; and DCP- and AFP-positive status (in combination), poorly differentiated histology, positive intrahepatic metastasis, and tumor diameter over 5 cm were independent factors of poor prognosis for disease free survival. CONCLUSIONS: The combination of DCP- and AFP-positive status is a new prognostic indicator for patients with HCC after hepatic resection.

Adult↗