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Biomedical subjects

T Maeda

Publications and source records attributed to T Maeda.

At least 271 records · Page 15Linked to original sources
PubMed1999

Neural connections of the pontine reticular formation, which connects reciprocally with the nucleus prepositus hypoglossi in the rat.

The pontine reticular formation connected with the nucleus prepositus hypoglossi was studied in the rat using anterograde and retrograde tracer techniques. The area reciprocally connected with the nucleus prepositus hypoglossi was evident in the pontine reticular formation of the rat. The region had intensive reciprocal connections with the ipsilateral subthalamic region, the contralateral pontine reticular formation and the nucleus prepositus hypoglossi. Furthermore, it was confirmed that the region received cholinergic projections mainly from the pedunculopontine tegmental nucleus and the laterodorsal tegmental nucleus, and aminergic projections from the dopaminergic cell groups A13 and A11, noradrenergic cell groups A7, A6 and A5, and the serotoninergic B9 cell group. This region in the rat was considered to be the preoculomotor structure in the function of horizontal gaze corresponding to the paramedian pontine reticular formation in other animals.

Animals↗
PubMed1999

Isolation of iron-oxidizing bacteria from corroded concretes of sewage treatment plants.

Thirty-six strains of iron-oxidizing bacteria were isolated from corroded concrete samples obtained at eight sewage treatment plants in Japan. All of the strains isolated grew autotrophically in ferrous sulfate (3.0%), elemental sulfur (1.0%) and FeS (1.0%) media (pH 1.5). Washed intact cells of the 36 isolates had activities to oxidize both ferrous iron and elemental sulfur. Strain SNA-5, a representative of the isolated strains, was a gram-negative, rod-shaped bacterium (0.5-0.6x0.9-1.5 microm). The mean G+C content of its DNA was 55.9 mol%. The pH and temperature optima for growth were 1.5 and 30 degrees C, and the bacterium had activity to assimilate 14CO2 into the cells when ferrous iron or elemental sulfur was used as a sole source of energy. These results suggest that SNA-5 is Thiobacillus ferrooxidans strain. The pHs and numbers of iron-oxidizing bacteria in corroded concrete samples obtained by boring to depths of 0-1, 1-3, and 3-5 cm below the concrete surface were respectively 1.4, 1.7, and 2.0, and 1.2 x 10(8), 5 x 10(7), and 5 x 10(6) cells/g concrete. The degree of corrosion in the sample obtained nearest to the surface was more severe than in the deeper samples. The findings indicated that the levels of acidification and corrosion of the concrete structure corresponded with the number of iron-oxidizing bacteria in a concrete sample. Sulfuric acid produced by the chemolithoautotrophic sulfur-oxidizing bacterium Thiobacillus thiooxidansis known to induce concrete corrosion. Since not only T. thiooxidans but also T. ferrooxidans can oxidize reduced sulfur compounds and produce sulfuric acid, the results strongly suggest that T. ferrooxidans as well as T. thiooxidans is involved in concrete corrosion.

Journal Article↗
PubMed1999

Poor outcome of autologous stem cell transplantation for adult T cell leukemia/lymphoma: a case report and review of the literature.

A limited number of patients with adult T cell leukemia/lymphoma (ATL) who received autologous stem cell transplantation (ASCT) have been reported. We report here a case of fatal systemic Candida krusei infection in a female patient with ATL undergoing ASCT. All of the eight patients (including seven patients in the literature) with ATL who received ASCT developed relapse of ATL or death due to ASCT complication, irrespective of subtype or remission state of ATL, source or selection of SCT or conditioning regimen. At present, ASCT appears to provide little benefit for ATL in contrast to that for other types of aggressive non-Hodgkin's lymphoma.

Adult↗
PubMed1999

Electromyographic study of the activity of jaw depressor muscles before initiation of opening movements.

The authors attempted to clarify the primary factors affecting the timing of the initial electromyographic discharges in the jaw depressor muscles (EMG onset). The changes in EMG onset in the inferior head of the lateral pterygoid (Lpt) and the anterior belly of the digastric muscles (Dig) were measured by varying duration of the open-close movement or occlusal force during the open-close-clench cycle (OCC). EMG onset tended to precede the beginning of the opening movement during OCC. The duration of opening and closing phase and the duration of occluding phase showed no significant correlation with the time-lag between EMG onset and the beginning of the opening movement (onset time). The mean EMG activity of the masseter muscle (Mm), corresponding to the occlusal force, showed a highly significant correlation with the onset time. The maximal opening velocity was highly correlated with the mean EMG activity of the jaw depressors before jaw opening. In conclusion, it was found that occlusal force is a major factor in EMG onset in the jaw depressors. It is suggested that smooth opening needs tooth contact with some degree of occlusal force.

Adult↗
PubMed1999

Motor activity of vascularly perfused rat duodenum. 1. Characteristics of spontaneous movement.

We developed an ex vivo model of arterially perfused rat duodenum to examine the motor activity of intestine. In this preparation, spontaneously occurring pressure waves with regular rhythm were observed. The oxygen consumption and motor activity of the intestine were compared at different arterial perfusion rates to determine the degree of oxygenation required to elicit spontaneous motility. Pressure waves with regular rhythm occurred at a frequency of 1 min-1 when the arterial perfusion was 3-5 mL min-1, and stopped when the perfusion rate fell below 2 mL min-1. Atropine and hexamethonium reduced the percentage motor index/10 min of pressure waves in a dose-dependent manner, and tetrodotoxin completely blocked motor activity. Acetylcholine stimulated motor activity, and this effect was not antagonized by TTX. These findings suggest that spontaneous contraction in the ex vivo perfused rat duodenum might be mediated by a cholinergic mechanism via muscarinic receptors on smooth muscle, but that noncholinergic mechanisms may also participate in this response.

Animals↗
PubMed1999

Motor activity of vascularly perfused rat duodenum. 2. Effects of VIP, PACAP27 and PACAP38.

We examined the mechanisms of effects of vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase activating polypeptide (PACAP) 27 and PACAP38 on spontaneously occurring pressure waves in ex vivo perfused rat duodenum. VIP and PACAPs dose-dependently reduced the percentage motor index of pressure waves; this reduction was not prevented by atropine, hexamethonium or tetrodotoxin (TTX). VIP and PACAPs abolished acetylcholine-induced stimulation of pressure waves, even in the presence of TTX. These findings suggest that VIP and PACAPs may exert direct inhibitory effects via VIP/PACAP receptors located on smooth muscle rather than via cholinergic receptors. The inhibitory effects of VIP and PACAPs were partially antagonized by the VIP receptor antagonists VIP(10-28), suggesting that VIP and PACAPs share common receptor sites on intestinal smooth muscle. The effects of VIP and PACAPs were completely antagonized by nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine (L-NA), suggesting that NO mediates the inhibitory effects of VIP and PACAPs on duodenal motility. Furthermore, single injection of L-NA stimulated spontaneously occurring pressure waves, while VIP(10-28) did not affect them. These findings suggest that VIP/PACAPs and NO strongly interact as an inhibitory mediator on duodenal motility, but that their modes of action in doing so may differ.

Animals↗
PubMed1999

Expression pattern, subcellular localization and structure--function relationship of rat Tpx-1, a spermatogenic cell adhesion molecule responsible for association with Sertoli cells.

The gene for a testicular cell adhesion protein called Tpx-1, which mediates the binding of spermatogenic cells to Sertoli cells of the rat in primary culture, was previously cloned. Here the characterization of Tpx-1 is reported. Tpx-1 messenger ribonucleic acid (mRNA) became detectable in pachytene spermatocytes and continued to be present throughout development into elongated spermatids, while the amount of Tpx-1 protein seemed to increase some time after the increment of mRNA. Tpx-1 protein was also present, although less abundantly, in spermatozoa prepared from the epididymis. Tpx-1 contains a cluster of hydrophobic amino acid residues near the amino terminus and a cysteine-rich region in the carboxyl-terminal half. Tpx-1 fused with green fluorescence protein was secreted into the medium when expressed in a cultured cell line, depending on the presence of the amino-terminal hydrophobic region. Moreover, Tpx-1 was present in the medium of testicular cell primary culture. Structure-function analysis revealed that the amino-terminal 101 amino acid residues were sufficient for cell adhesion activity, whereas the carboxyl-terminal cysteine-rich region was dispensable. In conclusion, Tpx-1 is produced and secreted from spermatogenic cells at various differentiation stages, and mediates the interaction of those cells with Sertoli cells.

Animals↗
PubMed1999

Effects of prone and supine position on sleep characteristics in preterm infants.

The purpose of this study was to address the influence of sleep position on sleep characteristics in preterm infants. We studied 16 infants at a mean post-conceptional age of 36.5 weeks. Infants were successfully recorded with videopolysomnograph in the supine and prone position. Between the two positions, there were no significant differences in percentage of active sleep and quiet sleep (QS), the occurrence of arousal, and the incidence of apnea. The first QS after the feeding was longer in the prone position. The sleep position could affect sleep characteristics but not respiratory characteristics in preterm infants.

Arousal↗
PubMed1999

Efficacy of antibiotics against influenza-like illness in an influenza epidemic.

AIM: To determine if an antibiotic reduces the incidence of complications associated with influenza-like illness during an influenza epidemic. METHODS: During the outbreak of influenza in Kobe in 1998, 85 patients suffering from an influenza-like illness were randomly assigned to two groups. Patients received placebo or sultamicillin orally for 4 days. The incidence of complications of influenza-like illness were compared and statistically assessed. RESULTS: There was no difference in the duration of fever or the incidence of acute otitis media. However, the incidence of pneumonia was significantly lower in the sultamicillin group than the placebo group (2.4 vs 16.3%, P < 0.05). CONCLUSION: Sultamicillin reduced the incidence of pneumonia associated with influenza-like illness during the influenza epidemic. This result suggests that antibiotics can reduce the rate of pneumonia associated with influenza.

Acute Disease↗
PubMed1999

Region-dependent difference in the sleep-promoting potency of an adenosine A2A receptor agonist.

The present study has demonstrated that the sleep-promoting potency of 2-[p-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamido adenosine (CGS21680), a selective agonist for the adenosine A2A receptor, varies depending on the location of the administration. CGS21680 was continuously administered to rats through a chronically implanted cannula for 6 h during their active phase. The tip of the cannula was located in the subarachnoid space or the brain ventricle neighbouring the established brain areas implicated in the regulation of sleep-wake phenomena, i.e. rostral basal forebrain, medial preoptic area, lateral preoptic area, posterior hypothalamus, and dorsal tegmentum of the pons and medulla. At an infusion rate of 2.0 pmol/min, the magnitude of increase in non-rapid eye movement sleep varied from 14 min (a 15% increase) to 96 min (a 103% increase), and those of rapid eye movement sleep varied from 6 min (a 40% increase) to 28 min (a 264% increase) from the respective baseline values. The largest increases in both types of sleep occurred when CGS21680 was administered to the subarachnoid space underlying the rostral basal forebrain. These findings were interpreted to mean that the major, if not the only, site responsible for the CGS21680-inducing sleep was located in or near the rostral basal forebrain. This interpretation was supported by the findings that the administration of CGS21680 to the rostral basal forebrain produced predominant expression of Fos within the shell of the nucleus accumbens and the medial portion of the olfactory tubercle, and that the microdialysis perfusion of CGS21680 into the shell of the nucleus accumbens also exhibited a sleep-promoting effect.

Adenosine↗
PubMed1999

Hypoxia potentiates ultraviolet A-induced riboflavin cytotoxicity.

Flavins are thought to be important chromophores for chronic photo-induced skin injury, but the mechanism is not well known. We have reported that the primary cytotoxicity remaining in ultraviolet A-irradiated riboflavin solution is attributable to hydrogen peroxide. Because the dermis is more hypoxic than the atmosphere, we investigated the cytotoxicity of riboflavin solution during and after ultraviolet A irradiation under hypoxia. Riboflavin solution showed stronger cytotoxicity during irradiation under hypoxia than under air. Riboflavin solution that had been irradiated under hypoxia at lower ultraviolet A doses showed stronger cytotoxicity and contained more hydrogen peroxide than solution irradiated under air at the same doses. At higher ultraviolet A doses, however, the cytotoxicity and hydrogen peroxide quantity were similar in riboflavin solutions irradiated under different oxygen conditions. The effect of a singlet oxygen quencher, sodium azide, on the induction of cytotoxicity and production of hydrogen peroxide by ultraviolet A irradiation of riboflavin solution was examined. The presence of sodium azide in the solution during ultraviolet A irradiation suppressed the cytotoxicity and hydrogen peroxide production to similar levels at various ultraviolet A doses regardless of oxygen conditions. At the maximum suppression by sodium azide, hydrogen peroxide production decreased to 10% of the unsuppressed production. About 40% of the oxygen molecules of hydrogen peroxide produced was thought to be derived from oxygen dissolved in the riboflavin solution.

Cell Line↗
PubMed1999

Effect of simvastatin on the lipid profile of hemodialysis patients.

BACKGROUND: Simvastatin, a 3-hydroxy 3-methylglutaryl co-enzyme A (HMG-CoA) reductase inhibitor, is used widely for treatment of hypercholesterolemia. Simvastatin may be a suitable treatment for dyslipidemia in hemodialysis (HD) patients. However, investigation of the side-effects and safety of long-term administration of simvastatin to HD patients has been limited. In this study, we investigated the effects and safety of simvastatin and its effects on lipoprotein metabolism in hypercholesterolemic patients on HD. METHODS: Simvastatin was administered at a dosage of 5 mg/day for 24 weeks to 38 HD patients with high serum total cholesterol (TC) levels (200 mg/dl) or low high-density lipoprotein cholesterol (HDL-C) levels (35 mg/dl). Every four weeks, serum lipids, apolipoprotein, lipoprotein (a) [Lp(a)] and malondialdehyde (MDA) levels were measured. In addition, lipid levels were determined in each lipoprotein fraction separated by ultracentrifugation. RESULTS: After 24 weeks of simvastatin administration, TC significantly decreased by 25.7%, and low-density lipoprotein cholesterol (LDL-C) was significantly decreased by 33.6%. Triglyceride (TG) and HDL-C showed no significant changes. Apolipoprotein (apo) B significantly decreased by 24.5% and apo E by 30.0%. No significant changes were observed in the other apolipoproteins. MDA was also significantly decreased, whereas Lp(a) was not significantly altered. In the lipoprotein fractions, very LDL cholesterol (VLDL-C), intermediate-density lipoprotein cholesterol (IDL-C), LDL1 cholesterol (LDL1-C), and LDL2 cholesterol (LDL2-C) showed significant decreases. No particular side-effects were observed during the 12 months of simvastatin administration. CONCLUSIONS: These results suggest that simvastatin appears to be safe and effective in HD patients with hypercholesterolemia.

Aged↗
PubMed1999

Endoscope disinfection using acidic electrolytic water.

BACKGROUND AND STUDY AIMS: The aim of the present study was to evaluate a new endoscope disinfector (WM-1) that uses acidic electrolytic water (AEW). MATERIALS AND METHODS: AEW was produced by electrolysis of a 0.05% NaCl-water mixture, with a redox potential greater than 1000 mV and a pH lower than 2.7. In the first study, an endoscope artificially contaminated with 15 species of bacteria and four strains of viruses was treated using the WM-1. In the second study, endoscopic contamination after clinical use was examined by culture for Helicobacter pylori and other bacteria, and by polymerase chain reaction for the H. pylori urease gene and hepatitis C virus. The extent of contamination was then examined after exposing the WM-1 to AEW. The safety of AEW was examined using both in vivo and in vitro studies. RESULTS: All of the bacteria and viruses were destroyed or inactivated after the instrument had been exposed to AEW. Clinical contamination was detected from the instrument in 19 of 30 endoscopic procedures, whereas no bacteria or viruses were detected after five minutes' exposure to AEW. AEW was found to be nonirritant, nontoxic to cells, and nonmutagenic. CONCLUSION: The WM-1 successfully and safely disinfected the endoscopes. With running costs of yen 24 per day ($0.21 per day), the WM-1 provides an effective and inexpensive alternative to conventional disinfection equipment.

Acids↗
PubMed1999

Differential expression of the splicing regulatory factor genes during two-step chemical transformation in a BALB/3T3-derived cell line, MT-5.

Although the alternative splicing of various genes is a common event in human tumors, the mechanisms behind it have not been characterized. We hypothesized that the expression of splicing regulatory factors would be changed during cellular transformation. Gene expression of three splicing regulatory factors, alternative splicing factor/splicing factor 2 (ASF/SF2), heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) and the 65 kDa subunit of U2 small nuclear ribonucleoprotein particles auxiliary factor (U2AF(65)), were examined by northern blotting in a two-step chemical transformation model. This in vitro model is composed of BALB/3T3 cells and a BALB/3T3-derived N-methyl-N-nitro-N-nitrosoguanidine (MNNG)-initiated cell line (MT-5). MT-5 cells can be transformed on exposure to 12-O-tetradecanoylphorbol-13-acetate (TPA). ASF/SF2 mRNA levels were decreased 2-fold in both MNNG-initiated cells and TPA-induced transformed cells compared with the normal parental cells, whereas hnRNP A2 mRNA expression did not significantly change between these three types of cells. U2AF(65) mRNA levels were markedly increased ( approximately 4.7-fold) associated with progression of cellular transformation. Moreover, RT-PCR analysis showed that distinct forms of ASF/SF2 mRNA were present in the MNNG-initiated cells and TPA-induced transformed cells but not in the parental cells. These findings indicate that ASF/SF2 or U2AF(65) gene expression is altered during in vitro two-step chemical transformation. The data suggest that the differential expression of splicing regulatory factors is one cause of aberrant expression of alternatively spliced mRNAs encoded by various genes in tumor cells.

3T3 Cells↗
PubMed1999

Immunohistochemical localization of carbonic anhydrase isozyme II in the gustatory epithelium of the adult rat.

The distribution of carbonic anhydrase isozyme II (CA II)-like immunoreactivity (-LI) in the gustatory epithelium was examined in the adult rat. In the circumvallate and foliate papillae, CA II-LI was observed in the cytoplasm of the spindle-shaped taste bud cells, with weak immunoreaction in the surface of the gustatory epithelium. No neuronal elements displayed CA II-LI in these papillae. There was no apparent difference in the distribution pattern between the anterior and posterior portions of the foliate papillae. In immunoelectron microscopy, immunoreaction products for CA II were diffusely distributed in the entire cytoplasm of the taste bud cells having dense round granules at the periphery of the cells. No taste bud cells displaying CA II-LI were detected in the fungiform papillae, but a few thick nerve fibers displayed CA II-LI. In the taste buds of the palatal epithelium, neither taste bud cells nor neuronal elements exhibited CA II-LI. The present results indicate that CA II was localized in the type I cells designated as supporting cells in the taste buds located in the posterior lingual papillae of the adult animal.

Animals↗