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Biomedical subjects

M Maeda

Publications and source records attributed to M Maeda.

At least 361 records · Page 20Linked to original sources
PubMed1998

Single stranded DNA as an immunocytochemical marker for apoptotic change of ischemia in the gerbil hippocampus.

The light and electron microscopic localizations of single stranded DNA (SSD) protein, a marker of apoptosis and programmed cell death, in the gerbil hippocampus were examined by immunocytochemistry after transient brain ischemia. SSD-immunoreactive (IR) cells appeared from post-operative day 1 (PO 1) to PO 7 after 5- or 10-min ischemia. Immunoreaction was recognized in the nucleus of the CA1 pyramidal neurons without remarkable morphological changes on PO 1. These findings suggest that SSD degradation can occur during delayed neuronal death in the CA1, preceding the appearance of double strand breaks, one of the characteristic features of apoptosis.

Animals↗
PubMed1998

Effects of mild and moderate hypothermia on cerebral metabolism and glutamate in an experimental head injury.

In this study we sought to determine the optimal brain temperature for treating compression-induced cerebral ischemia. Six cats each were treated with a deep-brain temperature of 37 degrees C (control), 33 degrees C (mild hypothermia), or 29 degrees C (moderate hypothermia). Intracranial pressure (ICP) and cerebral blood flow (CBF) were monitored, as were arteriovenous oxygen difference (AVDO2) and cerebral venous oxygen saturation (ScvO2). The cerebral metabolic rate of oxygen (CMRO2) was calculated. Extracellular glutamate concentration was measured by microdialysis. ICP was increased by inflation of an epidural balloon until CBF became zero. This ischemia was maintained for 5 min, after which the balloon was deflated. Mild hypothermia showed coupled CBF-metabolic suppression, but moderate hypothermia resulted in disproportionately increased AVDO2, decreased ScvO2, and low CBF/CMRO2 (relative ischemia). Reactive hyperemia after balloon deflation was decreased after both mild and moderate hypothermia, as was the tissue volume showing Evans blue dye extravasation. Extracellular glutamate increased in control animals, an effect most effectively suppressed in the mild hypothermia group. These data favor 33 degrees C as the optimal temperature for treating compression-related cerebral ischemia.

Animals↗
PubMed1998

Control of ICP and the cerebrovascular bed by the cholinergic basal forebrain.

The involvement of the cholinergic basal forebrain in the control of ICP and the cerebrovascular bed was investigated by simultaneous measurement of CBF, BP, ICP and ETCO2 in rats and cats. Single unit spikes were also continuously recorded during ICP changes in the dorsomedial hypothalamic nucleus (DMH) of cats. Glutamate or acetylcholine (Ach) microinjection into the magnocellular basal nucleus (nucleus basalis Meynert: NBM, substantia innominata: SI) of rats or the DMH of cats caused persistent increases in ICP associated with slightly decreased BP. Microinjection of Ach into the NBM or the DMH also induced consistent increases in CBF in the cerebral cortex. Spike activities in DMH neurons increased before and during spontaneous ICP elevation. The firing rate of the DMH neurons increased in phase with the plateau wave-like ICP variations elicited by microinjection of Ach into the cholinoceptive pontine area or the contralateral DMH. Glutamate- or Ach-induced increases in ICP resulted from an increased CBV in response to a reduced cerebral vasoconstrictor tone. Activity within the cholinergic basal forebrain, as well as the central noradrenergic system, contribute to ICP changes and may be the intrinsic neuronal origin of the plateau waves occurring in some pathological conditions.

Acetylcholine↗
PubMed1998

[Two staged Starnes operation for Ebstein's anomaly with pulmonary atresia in early infancy--a report of a successful case].

Severe tricuspid valve regurgitation and decreased pulmonary blood flow in neonatal Ebstein's anomaly with pulmonary atresia, may result in cardiac respiratory failure and hypoxemia. The poor natural course and lack of standard surgical treatment make treatment for neonatal Ebstein's anomaly very difficult. The Blalock-Taussig operation was performed for hypoxemia in Ebstein's anomaly associated with pulmonary atresia and severe tricuspid regurgitation on 36th day after birth. On the 63rd day after birth, tricuspid valve orifice closure and right atrium plication (Starnes procedure) were accomplished under cardiopulmonary bypass. Heart failure became controllable and the patient condition was satisfactory at one year after surgery.

Anastomosis, Surgical↗
PubMed1998

Local application of basic fibroblast growth factor minipellet induces the healing of segmental bony defects in rabbits.

Fibroblast growth factor (FGF) has been reported to increase the volume of callus in a fracture model of rats. There are, however, no reports of successful repair of segmental bony defects by application of an FGF solution. In this study, the effects of basic FGF on the repair of segmental bony defects in the rabbit femur were examined. Minipellet, a new drug delivery system using atelocollagen, was employed to ensure effective delivery of FGF. Segmental bony defects (10 mm in length) were created in the right femurs of 19 rabbits. In pilot studies, no defects of this size healed spontaneously within 6 weeks. Bones were stabilized with miniexternal fixators. Minipellets containing basic FGF were implanted between fragments so as to bridge the two fragments. The healing processes were monitored radiographically and studied histologically. In rabbits in which FGF was added to the defect site at doses of 1.4 microgram or higher, approximately 90% of the defects were filled with new bone and cartilage within 6 weeks after minipellet implantation. In rabbits receiving placebo minipellets, however, approximately 15% of the defects were filled by callus within 6 weeks. Furthermore, this callus did not change into mature bone. An injection of 2 microgram of FGF solution to bony defects had no effect on the repair of segmental bony defects. These findings suggest that FGF plays a role in the production of adequate volumes of callus particularly in the initial stages of fracture healing and that sustained local release enables FGF to be effective at a low dose. In summary, large segmental bony defects healed after insertion of low-dose FGF minipellets. An adequate dose of FGF and an appropriate delivery system are required for successful healing of large bony defects. These findings imply the potential value of FGF minipellets in clinical practice.

Animals↗
PubMed1998

Aggressive non-Hodgkin's lymphoma after successful eradication of Helicobacter pylori and regression of gastric lymphoma of mucosa-associated lymphoid tissue.

A 57-year-old woman presented to our clinic with low-grade gastric lymphoma of mucosa-associated lymphoid tissue (stage IE) and Helicobacter pylori infection. She received a 2-week course of omeprazole and clarithromycin, resulting in eradication of H. pylori and histological disappearance of the lymphoma. However, 9 months later (May 1996), multiple mass lesions were found around the pancreas and hepato-duodenal ligament on abdominal computed tomography. Inguinal lymph node biopsy revealed aggressive nodal type B-cell non-Hodgkin's lymphoma, diffuse large cell type. She received chemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone, but failed to achieve remission and died in December 1996. There was no evidence of recurrent gastric lymphoma. This case emphasizes the importance of performing follow-up examinations to detect other neoplasms in patients with gastric lymphoma of mucosa-associated lymphoid tissue.

Diagnosis, Differential↗
PubMed1998

Unco-parahippocampectomy for direct surgical treatment of downward transtentorial herniation.

Downward transtentorial herniation is a major cause of death and disability caused by acute supratentorial mass lesions. Thirteen patients, 7 men and 6 women aged from 23 to 75 years old, with progressive transtentorial herniation caused by cerebral contusion with acute subdural haematoma, acute brain swelling after aneurysmal subarachnoid haemorrhage, or massive cerebral infarction were treated by direct surgery using selective removal of the uncus and parahippocampal gyrus (unco-parahippocampectomy). All patients showed progressive deterioration of transtentorial herniation (late third nerve stage or midbrain stage) with unilateral pupillary dilation and absent light reflex. Preoperative Glasgow Coma Scale scores ranged from 4 to 8. Unco-parahippocampectomy was performed via the middle temporal gyrus under the operating microscope. The oculomotor nerve, posterior cerebral artery, and midbrain were directly decompressed. Incision of the arachnoid membrane in the tentorial incisura allowed free communication of the cerebrospinal fluid between the supra- and finfra-cranial fossae to reduce the pressure gradient. Two of the 13 patients died (15%). Two of the 11 survivors (18%) were functionally independent and 1 (9%) required minimal assistance but was independent at home. This series suggests the lifesaving nature of unco-parahippocampectomy in patients with deteriorating clinical condition because of transtentorial herniation.

Adult↗
PubMed1998

Thirty-day operative mortality for thoracotomy in lung cancer.

OBJECTIVE: The 30-day operative mortality for thoracotomy in lung cancer is described herein. METHODS: From January 1994 through December 1994, the Japanese Association for Chest Surgery surveyed the number of thoracotomies for lung cancer by operative procedure, age, and operative mortality. The operative mortality was defined as death within 30 days of operation. RESULTS: The total number of operations was 7099. The overall 30-day operative mortality was 1.3%. By operative procedure, the mortalities were 3.2% for pneumonectomy, 1.2% for lobectomy, and 0.8% for a lesser operation, which showed a significant difference between pneumonectomy and lobectomy (p < 0.01). The mortality by age was 0.4% for patients younger than 60 years, 1.3% for those aged 60 to 69, 2.0% for those aged 70 to 79, and 2.2% for those aged 80 or older, which showed significant differences between the less than 60-year and 60- to 69-year-old groups, and between the 60- and 69-year-old and 70- and 79-year-old groups (p < 0.01 and p = 0.047, respectively). Pneumonia and respiratory failure caused most deaths (51.6%). CONCLUSIONS: The operative mortality in Japan for thoracotomy in lung cancer was satisfactorily low. The results of this study on a large population could serve as a standard when discussing the operative outcome of lung cancer.

Age Factors↗
PubMed1998

Differentially expressed olfactomedin-related glycoproteins (Pancortins) in the brain.

Messenger RNA differential display is conducted to search for genes that are expressed in a region-specific pattern in the rodent brain. Eleven novel gene fragments are isolated. One of these genes which we call pancortin, based on its predominant mRNA expression in the cerebral cortex of the adult, is studied. These pancortin cDNA clones are grouped into four different types of cDNA, designated as pancortin-1 to -4. All pancortin cDNAs share a common sequence in the middle of their structure, having two alternative sequences at both 5'- and 3'-ends, respectively. Deduced amino acid sequence shows that all pancortins have sequences of hydrophobic amino acids at N-terminus and no obvious membrane spanning regions. In situ hybridization histochemistry using oligonucleotide probes specific for 5'- and 3'-end variable parts has revealed that these four pancortin mRNAs are expressed differentially in the adult rodent brain. Robust expression of pancortin-1 and -2 mRNA is observed in the cerebral cortex (including the hippocampus and the olfactory bulb). However, little of pancortin-3 and -4 mRNA is observed there. In the cortex, some neurons are stained by an antibody raised against Pancortin. Immuno-electron microscopic study has revealed that Pancortin-like immunoreactive products are localized mainly in the endoplasmic reticulum and not in the Golgi apparatus indicating that Pancortins are the endoplasmic reticulum-anchored proteins. Our results suggest that each Pancortin is differentially regulated and may perform different functions in the brain.

Amino Acid Sequence↗
PubMed1998

Interaction between sodium ascorbate and dopamine.

The interaction between sodium ascorbate and dopamine was investigated by three different parameters: radical intensity, prooxidant action, and cytotoxicity induction. Sodium ascorbate and dopamine produced the doublet and quartet ESR signals under alkaline conditions (pH 8.0-9.5), respectively. Addition of increasing concentrations of sodium ascorbate completely scavenged the dopamine radical and replaced the latter with its own radical. Similarly, dopamine slightly, but significantly reduced the radical intensity of sodium ascorbate. These two compounds stimulated the methionine oxidation and hydrogen peroxide generation in culture medium, but in combination, their stimulation activities were weakened. Both of these two compounds dose-dependently reduced the viable cell number of human oral squamous carcinoma HSC-4 cells, and their cytotoxic activity was significantly reduced by catalase. When these two compounds were mixed together before adding to HSC-4 cells, both of their cytotoxic activities were diminished. The present study demonstrates the interaction between sodium ascorbate and dopamine, which might modify their biological activities and generation of nerve disorders such as Parkinson's disease.

Amino Acids↗
PubMed1998

The effect of electrical acupuncture-stimulation therapy using thermography and plasma endothelin (ET-1) levels in patients with progressive systemic sclerosis (PSS).

In all 11 patients with progressive systemic sclerosis (PSS; Barnett type I, 2; type II, 5; type III, 4 cases; male 1; female 10 cases; 45.2 +/- 10.2 years-old), 6 cases of scleroderma spectrum disorders (SSD, male 1; female 5 cases; 51.2 +/- 13.2 years-old) and 7 healthy controls (HC, male 1; female 6 cases; 43.1 +/- 8.4 years-old) were entered to be examined. The plasma endothelin-1 (ET-1) levels of PSS, SSD and HC were 1.98 +/- 0.69, 1.76 +/- 0.39 and 1.15 +/- 0.38 pg/ml, respectively. After the stimulation with the low frequency electrical current, electrical acupuncture, for unilateral side of hand/arm (30 min), the plasma ET-1 levels decreased in 10 cases of PSS treated (1.61 +/- 0.45 pg/ml), but no change of plasma serotonin levels. In 4 of 6 cases of SSD, plasma ET-1 levels increased (2.06 +/- 0.39 pg/ml), however, nitrate levels increased and serotonin decreased in 3 of 5 cases of SSD. In 6 cases of HC treated with the electrical acupuncture, the plasma ET-1 levels increased (1.72 +/- 0.58 pg/ml). Thermographically, 9 of 11 cases of PSS and 5 of 6 cases of SSD showed temporally temperature-elevation of hand/fingers not only in treated sides, but also in non treated sides, although none of 7 HC showed temperature-elevation of hands/fingers. The decrease in plasma ET-1 levels due to the electrical acupuncture was thought to induce the vasodilatation and elevate the surface temperature in patients with PSS. These results will provide an excellent basis to study the efficacy of electrical acupunctural stimulation.

Acupuncture Therapy↗
PubMed1998

Further purification and structural analysis of calcium spirulan from Spirulina platensis.

An antiviral sulfated polysaccharide, calcium spirulan (Ca-SP), isolated from Spirulina platensis, was subjected to further purification. Ca-SP was found to be composed of rhamnose, 3-O-methylrhamnose (acofriose), 2,3-di-O-methylrhamnose, 3-O-methylxylose, uronic acids, and sulfate. The backbone of Ca-SP consisted of 1,3-linked rhamnose and 1,2-linked 3-O-methylrhamnose units with some sulfate substitution at the 4-position. The polymer was terminated at the nonreducing end by 2,3-di-O-methylrhamnose and 3-O-methylxylose residues.

Antiviral Agents↗
PubMed1998

Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa isolation from pharyngeal swab cultures among the Japanese elderly at admission to a geriatric hospital.

The isolation rate of Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa from pharyngeal swab cultures in the Japanese elderly was studied at admission to a geriatric hospital which had long-term care units. The subjects were 233 consecutive patients who were admitted to K Hospital in the time period April 1994 to March 1996. The isolation rate of MRSA and of Pseudomonas aeruginosa was 10.3% and 8.2% respectively. The proportions of the patients with severely to moderately limited Activities of Daily Living (ADL) (ADL score = 0-1) (P < 0.01), those with fever (P < 0.01), those with CRP positive (P = 0.04) and those with hypoalbuminemia (serum albumin < 3.5 g/dl) (P < 0.01) were higher in the MRSA positive patients than in the negative patients while the proportion of the patients with fever was higher in the Pseudomonas aeruginosa positive patients than in the negative patients (P < 0.02). In the multiple logistic regression analysis, the limitation of ADL (ADL score 0-1 vs 2-3, OR = 1.54, 95% CI = 1.02-2.33) and fever (with vs without, OR = 1.77, 95% CI = 1.18-2.66) remained as risk factors for the isolation of MRSA while only fever (with vs without, OR = 1.67, 95% CI = 1.11-2.53) remained as a risk factor for the isolation of Pseudomonas aeruginosa.

Activities of Daily Living↗
PubMed1998

Monoclonal-based enzyme-linked immunosorbent assay and immunochromatographic rapid assay for monensin.

Monensin, a member of the ionophoric polyether antibiotics, is used primarily as a coccidiostat. A protein conjugate of monensin was prepared and utilized to produce monoclonal antibodies in the BALB/c-P3X63Ag8U.1 fusion system. Only one hybridoma that produces monoclonal antibody against monensin was isolated from one in 329 wells. The monoclonal antibody was used to develop quantitative assays for monensin by means of an enzyme-linked immunosorbent assay (ELISA). The detection limit was 1 ng ml-1 and the relative standard deviations were 2.1-6.3% intra-assay and 5.9-12.9% inter-assay. All ELISA results for assay of chicken plasma and cattle milk were confirmed using a bioassay to be used as the official method. The ELISA and bioassay results showed close correlations for plasma (r2 = 0.98, n = 25) and milk (r2 = 0.95, n = 25). Using the anti-monensin monoclonal antibodies produced, a rapid test kit based on the immunochromatographic method was developed. Detection limits of monensin for cattle milk, cattle plasma and chicken plasma were about 40, 40 and 160 ppb. respectively.

Animals↗
PubMed1998

Histologic findings in polyacrylamide-coated polytetrafluoroethylene (PTFE) arterial grafts in the rat abdominal aorta.

To improve cell attachment without inducing thrombogenesis, the authors coated the inner surface of polytetrafluoroethylene (PTFE) prostheses (I.D.: 1 mm; length: 10 mm; wall thickness: 0.5 mm; fibril length: 30 microm) with polyacrylamide (PAA), known to have a strong antithrombotic effect (PAA-PTFE). They implanted the prostheses into the abdominal aorta of rats, and retrieved them at intervals of up to 9 months. Graft healing was observed under light and scanning electron microscopy. All the inner surfaces of the grafts examined were barely covered with fibrin or platelets. The PAA-coated fibers had many projections, in contrast to the original PTFE prostheses. Neo-endothelium was observed to be directly attached to these structural fibers of the PAA-PTFE grafts. Restoration of the neointima was also observed in these vascular prostheses.

Acrylic Resins↗
PubMed1998

Mechanism of 201thallium-chloride uptake in tumor cells and its relationship to potassium channels.

The purpose of this study was to elucidate the mechanism of 201Thallium-chloride (201Tl) uptake in tumor cells and its possible relationship to potassium channels. The subcellular biodistribution of 201Tl in tumor cells was examined in colon cancer (LS180) bearing nude mice using sequential centrifugation. The involvement of potassium channels in 201Tl uptake in tumor cells was examined by uptake inhibition with potassium channel blockers (ouabain, bumetanide, and glibenclamide) in cultured leukemia cells (K562). Greater than 90% of 201Tl was found in the soluble cytoplasmic fraction. 201Tl uptake was inhibited by ouabain and bumetanide but not by glibenclamide. These data demonstrate that 201Tl uptake in tumor cells is mediated by the Na(+)-K+ ATPase and the Na(+)-K(+)-2Cl- cotransporter with 201Tl acting as a potassium analogue.

Adenosine Triphosphate↗
PubMed1998

Effects of mild (33 degrees C) and moderate (29 degrees C) hypothermia on cerebral blood flow and metabolism, lactate, and extracellular glutamate in experimental head injury.

The effects of mild (33 degrees C) and moderate (29 degrees C) hypothermia were investigated to determine which temperature was more effective against compression-induced cerebral ischemia. Eighteen cats were anesthetized. The animals were divided into three groups according to deep-brain temperature (control, 37 degrees C; mild hypothermia, 33 degrees C; and moderate hypothermia, 29 degrees C). Intracranial pressure (ICP) and cerebral blood flow (CBF) were monitored, the latter by hydrogen clearance. Arteriovenous oxygen difference (AVDO2) and cerebral venous oxygen saturation (ScvO2) were measured in blood samples from the superior sagittal sinus. The cerebral metabolic rate of oxygen (CMRO2) and the cerebral metabolic rate of lactate (CMR lactate) were calculated. Extracellular glutamate was measured by microdialysis. ICP was increased by inflation of an epidural balloon until CBF became zero, and this ischemia was maintained for 5 min, after which the balloon was quickly deflated. All parameters were recorded over 6 h. Evans blue was injected to examine vascular permeability changes. CBF was decreased by 56% by mild hypothermia and by 77% by moderate hypothermia. Mild hypothermia had a coupled metabolic suppression whereas moderate hypothermia significantly increased AVDO2 and decreased ScvO2, producing a low CBF/CMRO2 (relative ischemia). After balloon deflation, all three groups showed reactive hyperemia, which was significantly reduced by mild and moderate hypothermia. CBF then decreased to 50% of pre-inflation values and ScvO2 decreased (post-ischemic hypoperfusion). CBF/CMRO2, ScvO2, and AVDO2 did not differ significantly between the three groups. After balloon deflation, all three groups showed increased CMR lactate, which was significantly reduced by mild and moderate hypothermia. Extracellular glutamate increased in control animals (3.8 +/- 1.72 microM), an effect most effectively suppressed in the mild hypothermia group (1.0 +/- 0.46 microM). Damaged tissue volumes as indicated by Evans blue dye extravasation were 729 +/- 89 mm3 in control, 247 +/- 56 mm3 in mild hypothermia, and 267 +/- 35 mm3 in moderate hypothermia animals. These data suggest that mild hypothermia (33 degrees C) might be the optimal brain temperature to treat compression-related cerebral ischemia.

Animals↗