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Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 433 records · Page 24Linked to original sources
PubMed1998

[A surgical case of angina pectoris with a severe stenosis of Lt. mid-cerebral artery: the usefulness of the monitoring of cerebral blood flow].

A 64-year-old male patient had two episodes of transient ischemic attack and a cerebral infarction. Cerebral angiography showed 50% stenosis at the junction of left internal carotid artery and 90% stenosis at left mid-cerebral artery (MCA). Coronary angiography showed two vessel disease with arteriosclerotic change and underwent coronary artery bypass grafting. To prevent intraoperative cerebral infarction, we used brain protect solution just before starting ECC, set perfusion flow around 3 l/min/m2, monitored the flow of left MCA using Transcranial Doppler (TCD) and the saturation of left internal jugular vein (SjO2) continuously. PaCO2 was controlled around 45 mmHg. TCD showed good pulsatile flow, and SjO2 was kept over 60%. The patient recovered consciousness 2 hours after operation in the intensive care unit without paresthesia. We thought the number of open-heart cases with cerebrovascular disease increased, and pulsatile low of ECC by intraaortic balloon pumping and the monitoring of SjO2 are useful for the cases.

Angina Pectoris↗
PubMed1998

Increase of low-affinity neurotrophin receptor p75 and growth-associated protein-43 immunoreactivities in the rat urinary bladder during experimentally induced nerve regeneration.

PURPOSE: Nerve regeneration in the urinary bladder after pelvic nerve plexus injury remains uncertain. The objectives were to establish a rat model of nerve regeneration in the bladder and to examine possible changes of low-affinity neurotrophin receptor p75 and growth-associated protein-43 (GAP-43) immunoreactivities during denervation and nerve regeneration. MATERIALS AND METHODS: Adult male rats were divided into 3 groups: controls, crush of the nerve bundles from the right major pelvic ganglion (MPG) to the bladder (nerve crush group) and removal of the right MPG (MPG removal group). Bladders were collected at 3, 7, 14, 30 and 60 days, and immunohistochemically stained for protein gene product 9.5 (PGP9.5: an axonal marker), p75 and GAP-43. RESULTS: In the nerve crush group, PGP9.5 positive nerves were decreased in number at 3 and 7 days, and then increased after 14 days in the muscle layer of the operated side. By 60 days, the density returned to control levels. However, MPG removal resulted in a decrease of the density of PGP9.5 positive nerves throughout the experimental periods. These findings indicate that nerve regeneration occurred in the nerve crush group. The density of p75 labeled fibers was significantly increased at 3 to 30 days postoperatively in the nerve crush group. p75 immunoreactivity showed smooth surface and cytoplasmic staining, indicating that Schwann cells were p75 positive. GAP-43 labeled fibers showed significantly greater density at 3 to 14 days postoperatively. Schwann cells were GAP-43 immunoreactive and, in particular, regenerating nerve fibers appeared to be GAP-43 positive at 14 days. CONCLUSION: The present study suggests that p75 and GAP-43 are involved in the mechanism(s) of nerve regeneration in the urinary bladder.

Animals↗
PubMed1998

[Remarkable increase of CD8+ CD11a+ and CD8+ CD57- T cells in patients with post-transfusion graft-versus-host disease].

We analyzed the distribution of two T cell subsets, CD8+ CD11a+ (CD8+ cytotoxic effector population) and CD8+ CD57- cells, in the peripheral lymphocytes of 3 post-operative patients with post-transfusion graft-versus-host disease (PT-GVHD) and 5 post-operative patients without PT-GVHD. The percentage of CD8+ CD11a+ cells in the PT-GVHD-negative control was 19 +/- 4%, and in the 3 patients with PT-GVHD, 69%, 66%, and 59%, respectively. The percentage of CD8+ CD57- cells in the PT-GVHD-negative control was 19 +/- 6%, and in the 3 PT-GVHD patients, 59%, 58%, and 55%, respectively. Significantly higher proportions of the two T cell subsets were consistently observed in the patients with PT-GVHD than in the PT-GVHD-negative control. These results suggest that the analysis of CD8+ T cell subsets may be useful for the simple and rapid laboratory diagnosis of PT-GVHD.

Acute Disease↗
PubMed1998

Effect of the angiotensin-converting enzyme inhibitor enalapril on post-transplant erythrocytosis.

Post-transplant erythrocytosis (PTE) is increasingly recognized as a complication of kidney transplantation. In this study we report the effect of the angiotesin-converting enzyme (ACE) inhibitor enalapril on hematocrit (Ht) and erythropoietin in four patients with PTE. Four renal allograft recipients with Ht greater than 51% were studied. Treatment was initiated with enalapril administered orally at a dose of 2.5 mg/day. All the patients had an increase of hemoglobin (Hb) (17.7 +/- 0.64 g/dl), Ht (54.5 +/- 1.29%) and red blood cell count (RBC) (584 +/- 19.2 x 10(4)/microliter). All patients responded to enalapril in 8 weeks with a significant decrease of Hb, Ht, and RBC. In one patient, the downward trend was more rapid and sustained, and treatment had to be discontinued to prevent the development of anemia. Serum erythropoietin showed normal in all four patients and remained unchanged during the study, even after discontinuation of enalapril treatment. Serum creatinine remained relatively stable throughout the study. These results suggest that PTE may not be dependent upon circulating erythropoietin and that enalapril treatment may be an effective treatment of PTE without renal dysfunction.

Adult↗
PubMed1998

Increased subglottic gallium uptake in relapsing polychondritis.

Gallium scintigraphy was performed on a 14-yr-old girl with subglottic airway narrowing that caused wheezing and dyspnea. The study showed increased gallium uptake in the neck. A biopsy was performed on the subglottic region, and the histology was compatible with relapsing polychondritis. After treatment with steroids, laboratory data that had indicated active inflammation soon normalized. Repeat gallium scintigraphy showed diminished uptake, although the subglottic stenosis did not improve. These results suggest that gallium scintigraphy is valuable for evaluating inflammatory activity in relapsing polychondritis.

Adolescent↗
PubMed1998

[Chronic liver disease prevents the development of atherosclerosis in spite the risk factor].

We investigated whether hypertension contributes to the development of atheloscrelosis in patients with chronic liver disease. There were no significant differences with respect to the ordinary biochemical data of serum concentrations of both protein and lipid metabolites between the hypertension group (n = 21) and the non-hypertension group (n = 31). In the hypertension group, serum creatinine level and serum concentration of lipoprotein (a) were significantly higher than those in non-hypertension group. However, there was no significant difference between the two groups with respect to the atherogenic index (apolipoproteins B versus A1 ratio). Serum glutamic oxaloacetic transaminase activity was positively correlated with serum apolipoprotein E concentration, and inversely correlated with serum lipoprotein (a) concentration, in 52 patients with chronic liver disease. Active hepatitis in patients with chronic liver disease might retard the development of atherosclerosis.

Aged↗
PubMed1998

Effects of maternal prone position on the umbilical arterial flow.

OBJECTIVE: The objective of our study was to clarify the effect of the maternal prone position on the feto-placental flow. In this position, the uterine compression of the large maternal vessels was expected to be completely eliminated. METHODS: Twenty-three normal pregnant women were cross-sectionally examined in the supine, the left lateral, the right lateral and the prone position. The systolic/diastolic ratios for the umbilical artery were calculated for each position. RESULTS: The umbilical arterial systolic/diastolic ratio in the prone position significantly decreased compared with that in the supine position. The left and right lateral position showed no significant change in the systolic/diastolic ratio. CONCLUSION: The maternal prone position can provide complete relief of uterine compression of the large maternal vessels.

Cross-Sectional Studies↗
PubMed1998

[A case of intrathoracic lipoma arising from the chest wall resected by video-assisted thoracoscopic surgery].

We present a case of lipoma arising from the chest wall spreading into the thoracic cavity. Although asymptomatic, a 65-year-old female was pointed out an abnormal shadow on the chest X-ray film taken at the mass survey. The tumor, measuring 3.4 x 3.0 x 2.0 cm in diameter, was surgically removed under thoracoscopic visualization through a small thoracotomy incision of lt. 1st intercostal space, and the diagnosis of lipoma was confirmed postoperatively by histopathologic examination.

Aged↗
PubMed1998

[123I-metaiodobenzylguanidine (MIBG) scintigraphy for the staging of neuroblastoma].

Nineteen children with neuroblastoma (aged 2 w.-7 y.o.) were studied to evaluate the optimal scan conditions for Iodine-123-Metaiodobenzylguanidine (MIBG) scintigraphy for accurate staging at the time of diagnosis. Six and 24 hours after an injection of 123I-MIBG, whole body image and truncal spot and SPECT images were obtained. Compared with other studies (CT or MRI and bone scintigraphy), each 123I-MIBG image was evaluated visually to investigate which image can demonstrate the extent of neuroblastoma most exactly. MIBG images demonstrated primary tumors in all patients, and metastatic lymphadenopathy in 8 of 9 patients. Twenty-four hour SPECT images gave us the most detailed information about the extent of abnormal accumulation. As to bone and bone marrow lesions, 6 hour images were superior to 24 hour images in detectability. Moreover, MIBG showed many more lesions and more extended accumulation than the bone scan. 123I-MIBG scintigraphy was very useful in detecting neuroblastomas. In order to get the most valuable information, both delayed SPECT and early whole body planar images should be obtained.

3-Iodobenzylguanidine↗
PubMed1997

Scanning and transmission electron microscopy of Ruffini endings in the periodontal ligament of rat incisors.

The Ruffini organ is an arborized axon ending categorized as a low-threshold stretch receptor. We have previously shown that the lingual periodontal ligament of rat incisors is densely innervated with Ruffini endings. In the present study, fine structures in the surface of the periodontal Ruffini endings and their topographical relationship with the surrounding collagen fibers were observed by a combination of scanning and transmission electron microscopy to analyze the mechanism of the stretch reception. The entire length of the branches of the Ruffini endings, excepting their terminal portions, corresponded well with those depicted by previous investigators in the following points: (1) their cylindrical appearance covered by Schwann cell processes; (2) the presence of numerous axon fingers protruding through gaps in the Schwann sheath and; (3) their isolation from collagen fibers by multilayered basal lamina. On the other hand, tips of the axon branches-together with their Schwann sheaths-became attenuated and projected into tight bundles of collagen, indicating their susceptibility to mechanical deformations of the surrounding tissue. Margins of the axon terminals were conspicuously ruffled with long tongue-like projections of Schwann cells. The Schwann cell tongues twined around collagen bundles in their distal portions, and associated closely with fine axon projections in their proximal portions, suggesting their involvement in the mechanical transmission of stimuli to axon terminals.

Animals↗
PubMed1997

Enhancement of DNA repair in human skin cells by thymidine dinucleotides: evidence for a p53-mediated mammalian SOS response.

Thymidine dinucleotide (pTpT) stimulates melanogenesis in mammalian pigment cells and intact skin, mimicking the effects of UV irradiation and UV-mimetic DNA damage. Here it is shown that, in addition to tanning, pTpT induces a second photoprotective response, enhanced repair of UV-induced DNA damage. This enhanced repair results in a 2-fold increase in expression of a UV-damaged chloramphenicol acetyltransferase expression vector transfected into pTpT-treated skin fibroblasts and keratinocytes, compared with diluent-treated cells. Direct measurement of thymine dimers and (6-4) photoproducts by immunoassay demonstrates faster repair of both of these UV-induced photoproducts in pTpT-treated fibroblasts. This enhanced repair capacity also improves cell survival and colony-forming ability after irradiation. These effects of pTpT are accomplished, at least in part, by the up-regulation of a set of genes involved in DNA repair (ERCC3 and GADD45) and cell cycle inhibition (SDI1). At least two of these genes (GADD45 and SDI1) are known to be transcriptionally regulated by the p53 tumor suppressor protein. Here we show that pTpT activates p53, leading to nuclear accumulation of this protein, and also increases the specific binding of this transcription factor to its DNA consensus sequence.

Cells, Cultured↗
PubMed1997

Monoamine oxidase B (MAOB)-containing structures in MAOA-deficient transgenic mice.

Monoamine oxidase (MAO)-containing structures were studied for the first time in type A MAO (MAOA)-deficient transgenic mice (Tg8) derived from C3H strain, using MAO enzyme histochemistry. In this mutant line, MAOA activity was not detected in neurons of the locus coeruleus. In contrast, in their dorsal raphe neurons, we noted an intense activity of type B MAO (MAOB). Based on pharmacological MAOA suppression experiments employing a specific inhibitor (clorgyline), we confirmed that the localization of MAOB-positive structures are not different between Tg8 mutant and normal C3H line. Many of MAOB-positive structures which have not been described previously in the rat, cat and primates were described in this study. In the forebrain, MAOB-containing neurons were discriminated in the striatum, septal nuclei, major island of Calleja, diagonal band, medial forebrain bundle, ventral pallidum and amygdaloid nucleus. Stained neurons in the thalamus and hypothalamus were much more extensively distributed in the mouse than the rat. Pontine laterodorsal tegmental neurons showed MAOB activity. The present data suggest that serotonin, a preferential substrate for MAOA, can be oxidized by MAOB in MAOA-deficient Tg8 mice.

Animals↗
PubMed1997

L-DOPA neurotoxicity is mediated by glutamate release in cultured rat striatal neurons.

The exposure of cultured rat striatal neurons to L-DOPA caused marked cell death. The L-DOPA cytotoxicity was inhibited by the addition of Mg2+ to and by the removal of Ca2+ from the culture medium, and also by the application of tetrodotoxin. Moreover, prolonged application of L-DOPA increased the glutamate content in the culture medium. These results indicate that L-DOPA produces neurotoxicity by facilitating glutamate release.

Animals↗
PubMed1997

Electron-microscopic study of MAOB-containing structures in the nucleus accumbens shell: using MAOA-deficient transgenic mice.

MAOB-containing structures in the nucleus accumbens were ultrastructurally studied for the first time, using MAOA-deficient transgenic mice and MAO enzyme histochemistry. Among the striatal structures, the nucleus accumbens, and in particular its dorsal shell, showed the strongest MAOB activity. MAOB-active cell bodies were embedded in a dense MAOB-active fiber plexus. MAOB-positive terminals formed axo-dendritic synapses which were exclusively of the asymmetric type. It is suggested that dopamine in the nucleus accumbens shell is transported into MAOB-positive fibers where it is degraded by MAOB.

Animals↗
PubMed1997

Modulation of cell-adhesive activity of fibronectin by the alternatively spliced EDA segment.

Fibronectin (FN) has a complex pattern of alternative splicing at the mRNA level. One of the alternatively spliced segments, EDA, is prominently expressed during biological processes involving substantial cell migration and proliferation, such as embryonic development, malignant transformation, and wound healing. To examine the function of the EDA segment, we overexpressed recombinant FN isoforms with or without EDA in CHO cells and compared their cell-adhesive activities using purified proteins. EDA+ FN was significantly more potent than EDA- FN in promoting cell spreading and cell migration, irrespective of the presence or absence of a second alternatively spliced segment, EDB. The cell spreading activity of EDA+ FN was not affected by antibodies recognizing the EDA segment but was abolished by antibodies against integrin alpha5 and beta1 subunits and by Gly-Arg-Gly-Asp-Ser-Pro peptide, indicating that the EDA segment enhanced the cell-adhesive activity of FN by potentiating the interaction of FN with integrin alpha5beta1. In support of this conclusion, purified integrin alpha5beta1 bound more avidly to EDA+ FN than to EDA- FN. Augmentation of integrin binding by the EDA segment was, however, observed only in the context of the intact FN molecule, since the difference in integrin-binding activity between EDA+ FN and EDA- FN was abolished after limited proteolysis with thermolysin. Consistent with this observation, binding of integrin alpha5beta1 to a recombinant FN fragment, consisting of the central cell-binding domain and the adjacent heparin-binding domain Hep2, was not affected by insertion of the EDA segment. Since the insertion of an extra type III module such as EDA into an array of repeated type III modules is expected to rotate the polypeptide up to 180 degrees at the position of the insertion, the conformation of the FN molecule may be globally altered upon insertion of the EDA segment, resulting in an increased exposure of the RGD motif in III10 module and/or local unfolding of the module. Our results suggest that alternative splicing at the EDA exon is a novel mechanism for up-regulating integrin-binding affinity of FN operating when enhanced migration and proliferation of cells are required.

Alternative Splicing↗
PubMed1997

Calretinin-like immunoreactivity in the Ruffini endings, slowly adapting mechanoreceptors, of the periodontal ligament of the rat incisor.

The distribution and ultrastructural localization of calretinin (CR)-like immunoreactivity (-LI) were investigated in the lingual periodontal ligament of rat incisors. Some thick nerve fibers within the nerve bundle displayed CR-LI; these CR-like immunoreactive (-IR) nerve fibers entered the alveolar half of the lingual periodontal ligament of the incisor where dendritic terminal arborization was exhibited. Thin and beaded CR-IR nerve fibers were rarely observed in the periodontal ligament. Observations of adjacent sections immunostained with protein gene-product 9.5 (PGP 9.5) revealed that most, if not all, PGP 9.5-IR nerve terminals showing a dendritic arborization expressed CR-LI. Immunoelectron microscopic observations showed that electron-opaque immunoreaction products were localized in the axoplasm of the axon terminals, except for the mitochondria, which were surrounded by Schwann sheaths and multiple-layered basal lamina. Neither cell bodies, the cytoplasmic extension of terminal Schwann cells, nor other cellular elements such as periodontal fibroblasts exhibited CR-LI. The present findings suggest that Ruffini endings, an essential mechanoreceptor in the periodontal ligament and categorized as a slowly adapting mechanoreceptor, express CR-LI, and that CR may participate in the Ca2+ homeostasis against external stimuli in the periodontal Ruffini endings.

Animals↗