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Biomedical subjects

S Kikuchi

Publications and source records attributed to S Kikuchi.

At least 145 records · Page 8Linked to original sources
PubMed2000

Lasting changes in NMDAR1 mRNA level in various regions of cerebral cortex in epileptogenesis of amygdaloid-kindled rat.

The involvement of NMDA receptor subunit, NR1, with kindling phenomenon has been reported, but the role of NR1 in epileptogenesis is still unknown. We have examined the expression levels of NR1 mRNA in the cerebral cortices of amygdaloid-kindled rats. Northern blot analysis showed a significant increase in NR1 mRNA expression level in the ipsilateral frontal and temporal cortices at 4 weeks after the last generalized seizure. At the same time, NR1 mRNA decreased in the bilateral piriform cortices. These data suggest that NR1-mediated transmission may have an impact in the neurobiological basis of enduring epileptogenesis.

Amygdala↗
PubMed2000

Ictal brain hemodynamics in the epileptic focus caused by a brain tumor using functional magnetic resonance imaging (fMRI).

Using functional magnetic resonance imaging (fMRI) we were able to observe, in detail, ictal brain hemodynamics during epileptic seizure caused by a brain tumor. A 53-year-old man was experencing partial motor seizures of the left side of his face and neck. In a brain MR image a mass lesion was found in the subcortical area of the right frontal lobe. We found focal spikes in his right hemisphere, though dominantly in C4 and T4 regions. fMRI investigations were carried out at 1.5 T (GE Signa Horizon) using gradient-echo echo-planar neuroimaging. We were able to perform the ictal examination twice. The activated regions were focalized and clearly found only on the lateral side of the tumor base. The region was in agreement with the epileptic focus examined using an electrocorticogram (ECOG). The signal intensity in the seizure focus rapidly increased 30 seconds before the convulsion was observed. After the end of the convulsion it also took 30 seconds to restore the signal intensity to the baseline value. fMRI is a very useful tool for various studies such as the identification of the epileptic focus, the mechanism of epileptic seizure, and so on.

Brain Mapping↗
PubMed2000

Cytokines and T-cell responses in superantigen-related glomerulonephritis following methicillin-resistant Staphylococcus aureus infection.

BACKGROUND: We have previously reported that 10 patients who developed glomerulonephritis (GN) in association with methicillin-resistant Staphylococcus aureus (MRSA) infection showed a marked increase in DR+CD4+ and DR+CD8+ subsets of T cells and in T cells expressing several T-cell receptor (TCR) V beta+cells, perhaps representing V beta-specific T-cell activation by MRSA-derived superantigens (Kidney Int 1995; 47: 207-216). In this study we examine cytokine levels, T-lymphocyte subsets, natural killer NK cells, memory T cells, and the expression of IL-2 receptors in order to better understand the role of bacterial superantigens and cytokines in the pathogenesis of MRSA-associated GN. METHODS: Twenty-two patients with MRSA infection who later developed GN caused by staphylococcal enterotoxin were evaluated immunologically in comparison with patients whose MRSA infection was not followed by GN (non-GN group) and normal individuals. RESULTS: Among peripheral lymphocytes, the frequency of T cells expressing several TCR V betas, especially V beta 5-family TCR, was higher in the GN group than in both the non-GN group and the normal healthy control group. GN patients also showed increased serum levels of several cytokines, including tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-2, IL-6, IL-8, and IL-10, which have been implicated in the onset of nephritis. Memory cells, and IL-2 receptors also were elevated in the GN group. CONCLUSION: These results suggest that T cells activated by MRSA-derived staphylococcal enterotoxins and subsequent production of cytokines may play an important role in the pathogenesis of MRSA-associated GN.

Adult↗
PubMed2000

Inhibitory effects of tranilast on the proliferation and functions of human pterygium-derived fibroblasts.

PURPOSE: We studied the possibility that tranilast, an antiallergic and antiproliferative drug, may be beneficial for the treatment of pterygium. METHODS: Pterygium-derived cells were identified by immunohistochemical methods. Growth rate of pterygium-derived cells was determined by using a hemocytometer. Chemotaxis was determined in a microchemotaxis chamber. Pterygium-derived cells were cultured on floating collagen gel, and the contracted diameter was measured. Collagen synthesis by pterygium-derived cells was determined by the collagenase digestive method. Tranilast was added to the culture medium at final concentrations of 0, 12.5, 25, 50, and 100 microg/ml. RESULTS: Pterygium-derived cells were stained with anti-prolylhydroxylase and anti-alpha-smooth muscle actin, and identified as fibroblasts. Tranilast inhibited the proliferation and chemotaxis of pterygium-derived fibroblasts, and the collagen-gel contraction induced by these cells, but it exerted no inhibitory action on collagen synthesis by pterygium-derived fibroblasts. CONCLUSION: Tranilast may be useful for suppressing the recurrence and, possibly, the development of pterygium.

Actins↗
PubMed2000

Suppression of lethal toxicity of endotoxin by biscoclaurine alkaloid cepharanthin.

Suppressive effects of Cepharanthin (CE) on lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNFalpha) production followed by liver injury were investigated. Pretreatment with CE reduced limulus activity of LPS. Intraperitoneal treatment with CE 10 min before an i.v. challenge of LPS resulted in protection from LPS lethality in D-galactosamine (GalN)-sensitized BALB/c but not in C57BL/6 and C57BL/10ScSn mice. Treatment with CE before the LPS challenge significantly reduced serum TNF levels in a dose-dependent manner. The suppression was most effective when CE was administered 10 min before the LPS challenge. Increased levels of enzymes released from hepatocytes into the circulation, as a result of LPS-induced liver injury, were reduced by CE administration. Histological evaluation demonstrated that massive cell infiltration after severe injury developed in liver of mice injected with LPS plus D-GalN unless they were pretreated with CE. Apoptotic cells decreased by treatment with CE. Treatment with CE retarded lethal shock induced by an infection with 10(8) CFU Salmonella typhimurium deltaaroA mutant. These results suggest that action of CE is initiated through suppression of LPS-induced TNF production.

Alanine Transaminase↗
PubMed2000

Long-term effect of Helicobacter pylori infection on serum pepsinogens.

Serum pepsinogen values are markers of gastric mucosal status and of gastric cancer risk. The effect of Helicobacter pylori infection and sibship size on change of serum pepsinogen values over a seven-year span was investigated. Data from 2584 subjects with phlebotomy were analyzed both in 1989 and in 1996. The subjects were classified by H. pylori serology and sibship size (1 - 3 vs. 4 and more). Pepsinogen I (PG I) to II (PG II) ratio in '96 minus that in '89 was defined as DeltaPG I / II and compared among the groups. DeltaPG I / II was lower and decrease of PG I / II was more frequent among H. pylori-positive subjects than among negative subjects. The difference was owing to a decrease of PG I in all subjects and owing to an increase of PG II in those not younger than 30 years in '89. In H. pylori-positive subjects, those with a larger sibship size showed lower DeltaPG I / II and higher frequency of PG I / II decline. H. pylori infection exerts a reducing effect on PG I / II during the seven-year span. The effect of H. pylori is stronger among those with a larger sibship size, who are expected to have been infected with H. pylori in childhood. Inducing atrophy of gastric mucosa, which is reflected by a decline of PG I / II, may be one of the mechanisms through which H. pylori elevates the risk of gastric cancer.

Adult↗
PubMed2000

Effect of age on the relationship between gastric cancer and Helicobacter pylori. Tokyo Research Group of Prevention for Gastric Cancer.

Helicobacter pylori is thought to be involved in the pathogenesis of gastric cancer, but the time point at which it produces its effects (critical time) is unknown. We measured the serum level of H. pylori antibody in 787 gastric cancer patients and 1007 controls aged 20 to 69. Odds ratios for different gastric cancer types and stages were determined for each 10-year age class. The overall odds ratio for gastric cancer decreased with age, being 7.0 for those aged 20 - 29, 14.5 for those aged 30 - 39, 9.1 for those aged 40 - 49, 3.5 for those aged 50 - 59, and 1.5 for those aged 60 - 69 (trend in odds ratios: P < 0.01). However, there was no such age-dependent trend for early diffuse-type cancer; the odds ratios were 12.6, 4.0, 7.2, 6.5, and 18.5 respectively (P = 0.29). Early cancer tended to show higher seroprevalence than advanced cancer, especially in older subjects. No significant difference in seroprevalence was observed between diffuse and intestinal cancers within each age-class. Seroreversion must have occurred in the time interval between the critical time and the diagnosis of the cancer, especially in older patients. The age-dependent relationship between H. pylori and gastric cancer may be due to seroreversion, which itself may be independent of age. This age-independence indicates that prolonged exposure to H. pylori does not increase the magnitude of its influence on gastric carcinogenesis. Possible mechanisms through which H. pylori exerts pathogenic effects are continuous inflammation in adulthood and / or irreversible damage to gastric mucosa in childhood or the teenage years.

Adult↗
PubMed2000

Valproic acid-induced hyperammonemic encephalopathy with triphasic waves.

PURPOSE: To examine a patient with valproic acid (VPA)-induced hyperammonemic encephalopathy accompanied by triphasic waves. METHODS: A 61-year-old male patient with epilepsy experienced disturbance of consciousness after VPA dose was increased because of poor seizure control. The electroencephalogram (EEG) taken on admission revealed triphasic waves and high-amplitude delta-activity with frontal predominance. Although serum hepatic enzymes, such as AST and ALT, were normal, serum ammonium level was high at 96 microg/dl (normal range, 3-47 microg/dl). Serum amino acid analysis showed multiple minor abnormalities. Administration of VPA was discontinued immediately after admission, while other anticonvulsants were continued. RESULTS: The patient's condition was improved on the fourth day of admission. An EEG, serum ammonium level, and amino acid profile were normal on the eighth day. Based on VPA administration, serum ammonium levels, and results of amino acid analysis, this patient had VPA-induced hyperammonemic encephalopathy. CONCLUSIONS: Our case indicates that caution is required if triphasic waves appear in VPA-induced hyperammonemic encephalopathy.

Amino Acids↗
PubMed2000

Viability of an Escherichia coli pgsA null mutant lacking detectable phosphatidylglycerol and cardiolipin.

Phosphatidylglycerol, the most abundant acidic phospholipid in Escherichia coli, has been considered to play specific roles in various cellular processes and is believed to be essential for cell viability. It is functionally replaced in some cases by cardiolipin, another abundant acidic phospholipid derived from phosphatidylglycerol. However, we now show that a null pgsA mutant is viable, if the major outer membrane lipoprotein is deficient. The pgsA gene normally encodes phosphatidylglycerophosphate synthase that catalyzes the committed step in the biosynthesis of these acidic phospholipids. In the mutant, the activity of this enzyme and both phosphatidylglycerol and cardiolipin were not detected (less than 0.01% of total phospholipid, both below the detection limit), although phosphatidic acid, an acidic biosynthetic precursor, accumulated (4.0%). Nonetheless, the null mutant grew almost normally in rich media. In low-osmolarity media and minimal media, however, it could not grow. It did not grow at temperatures over 40 degrees C, explaining the previous inability to construct a null pgsA mutant (W. Xia and W. Dowhan, Proc. Natl. Acad. Sci. USA 92:783-787, 1995). Phosphatidylglycerol and cardiolipin are therefore nonessential for cell viability or basic life functions. This notion allows us to formulate a working model that defines the physiological functions of acidic phospholipids in E. coli and explains the suppressing effect of lipoprotein deficiency.

Cardiolipins↗
PubMed2000

Acquired anomalous intrapulmonary venous connection secondary to pulmonary venous stenosis.

An unusual case of acquired development of anomalous intrapulmonary venous connection with pulmonary venous stenosis is presented. Appearances on a chest radiograph resembled the "scimitar" sign in a patient with previous surgery for partial anomalous pulmonary venous return. Spiral CT and pulmonary arteriography showed stenosis of the right upper pulmonary vein and an anomalous intrapulmonary venous connection between the right upper pulmonary vein and the right lower pulmonary vein. We consider the slow progression of pulmonary vein stenosis led to anomalous intrapulmonary venous connection as an intrapulmonary collateral.

Adult↗
PubMed2000

Femoral bone density and changes therein associated with differing histories of pregnancy and lactation in aged rats.

OBJECTIVE: To examine the effect of prior pregnancy and lactation on bone density in aged rats. MATERIALS AND METHODS: 2 month-old female Fischer-344 rats were divided into 4 groups: 1)13 rats were allowed to get pregnant and to nurse their offspring for two or three cycles; 2)14 rats were allowed to get pregnant two or three times and were immediately separated from their young after each delivery prior to lactation; 3)10 rats were not allowed to become pregnant; and 4)7 rats were sacrificed at the beginning of the experiment. All rats were fed ad libitum. After the rats had completed two or three pregnancies with or without subsequent lactation, all were fed a restricted diet until they were 25 months old (aged rats). Then they were sacrificed and both femurs were removed from each rat. One bone was used for analysis of mineral content and the other bone was used for photodensitometry of the diaphysis. RESULTS: 31 rats (83.8% ) survived until they were sacrificed. The femurs of the aged rats showed increased ash weight compared to those of 2 month-old rats. Aged rats with prior pregnancies with or without subsequent lactation had higher femoral ash weight than those without prior pregnancies. There were no differences among aged rats in regard to marrow diameter, bone diameter, cortical width or bone density of the diaphysis in femur by photodensitometry. CONCLUSION: In aged rats, past pregnancies but not lactation were related to increases in bone density of the femur.

Aging↗
PubMed2000

Paradoxical progression of biliary strictures against recovery of biochemical parameters under ursodeoxycholic acid treatment in a case of primary sclerosing cholangitis with ulcerative colitis.

Ursodeoxycholic acid (UDCA) treatment for primary sclerosing cholangitis (PSC) has been considered a rational therapy, though its effectiveness in the clinical course is still open to discussion. In this report, we describe a 22-year-old man with PSC at an early stage, which was associated with ulcerative colitis (UC). He showed progressive strictures of bile ducts over a 1.5-year period in spite of an improvement in the biochemical parameters by UDCA treatment. Therefore, care should be taken in interpreting the effectiveness of UDCA, because the biochemical parameters may not change in parallel with the clinical course of PSC.

Adult↗
PubMed2000

A high level of physical fitness during thirties is a negative risk factor for colonic polyps during fifties.

This case-control study examined the relationship between the occurrence of colonic polyps in men in their fifties and the level of their physical fitness while in their thirties. The subjects consisted of 51 male Japan Self-Defense Forces officials in their fifties who had colonic polyps, as diagnosed by colonoscopic examination, and 46 control individuals. As an indicator of physical fitness between 30 and 39, we selected the best time recorded for each individual during that decade of life for the 1,500 meter Physical Fitness Test run. We calculated the odds ratio for polyps according to selected risk factors (including physical fitness), and a logistic regression analysis was used to adjust for possible confounding variables. Odds ratio (95% confidence interval, p value) for colonic polyps with physical fitness in the thirties was 0.36 (0.16-0.82, p < 0.05). With adjustment for the subjects' maximum Body Mass Index in both their thirties and fifties, and serum total cholesterol, the odds ratio was 0.39 (0.15-0.99, p < 0.05). We suggest that the occurrence of colonic polyps in men in their fifties can be reduced by maintaining a high level of physical fitness while in their thirties.

Adult↗
PubMed2000

Lymph-node staining with activated carbon CH40: a new method for axillary lymph-node dissection in breast cancer.

OBJECTIVE: To demonstrate the usefulness of activated carbon particles (CH40) as a vital staining dye for visualizing lymphatic vessels and lymph nodes in breast cancer. DESIGN: A retrospective evaluation. SETTING: Department of Surgery in Sendai National Hospital, Japan, a 716-bed teaching hospital. METHODS: To identify as many lymph nodes as possible in the axillary fat, by which we might decrease the possibility of the presence of undetected metastatic nodes, an emulsion of activated carbon particles (CH40) was injected into the centre of the mammary gland, close to the tumour site, 3 days before radical surgery. MAIN OUTCOME MEASURE: The number of lymph nodes found by the traditional method and by the CH40-injection method were recorded. RESULTS: After injection, the CH40 was readily adsorbed into regional lymphatics and streamed along with the lymph flow to blacken regional lymph nodes. The CH40-guided method increased the mean number of nodes per case found in the axilla from 8.4, by the traditional method, to 14.0 nodes per case. CONCLUSIONS: The use of the CH40 technique has two technical advantages; one is that it allows surgeons to locate the blackened lymph nodes at the time of surgery and the other is that it allows pathologists to look for the nodes in fatty tissue. Lymph-node dissection with the aid of activated carbon particles is inexpensive, easy to perform and enables the smallest lymph nodes to be easily recognized. CH40 is the technique of choice for the detection of axillary lymph nodes in cases where the number of lymph nodes detected by the traditional method is too small for accurate surgery. In conclusion, the present study demonstrates that CH40 could be an appropriate tool for more accurate staging of breast cancer axillary specimens.

Adult↗
PubMed2000

[Anesthetic management for reconstruction of the superior vena cava by monitoring of peripheral venous pressure in a patient with a mediastinum tumor].

A 26-years-old man with a giant mediastinum tumor was scheduled for reconstruction of the superior vena cave and tumor resection. Anesthetic management for reconstruction of the superior vena cava was performed by monitoring of peripheral venous pressure. A bypass between the inominate vein and right auricula was made by using an artificial vessel before clamping the superior vena cava. When the superior vena cava was clamped, peripheral venous pressure increased suddenly to 42 mmHg. Immediately after the venesection from the peripheral vessel, it was possible to control peripheral venous pressure at about 20 mmHg. Blood was re-transfused from the femoral vein to the patient. Cerebral neurological symptom due to the increasing venous pressure was not detected. In conclusion, monitoring peripheral venous pressure during reconstruction of the superior vena cava in a patient with a mediastinum tumor may be a useful technique.

Adult↗