Biomedical subjects

K Imai

Publications and source records attributed to K Imai.

At least 163 records · Page 9Linked to original sources

PubMed2001

Human collagenase (matrix metalloproteinase-1) expression in the lungs of patients with emphysema.

Pulmonary emphysema is believed to result from an imbalance between proteolytic enzymes and their inhibitors. Multiple studies have examined the presence of various proteases within the bronchoalveolar lavage fluid from patients with chronic obstructive pulmonary disease (COPD). However, to date extensive examination of the lung parenchyma for the expression of destructive enzymes has not yet been determined. The following study examines the lung parenchyma of 23 patients with emphysema and 8 normal control samples for the expression of matrix matalloproteinase-1 (MMP-1), MMP-12, and MMP-9. We report here that interstitial collagenase (MMP-1) RNA, protein, and activity are present in the lung parenchyma of patients with emphysema and not in the lung of normal control subjects. In contrast, metalloelastase (MMP-12) expression is absent in these samples. Immunohistochemistry studies localized MMP-1 to the Type II pneumocyte in patients with emphysema and not normal control subjects or smokers without emphysema. This observation demonstrates that the lung is altered in emphysema such that the Type II pneumocyte secretes MMP-1 and suggests that MMP-1 may be an important enzyme involved in the destruction of the lung in the human disease. In addition, the induction of a proteolytic enzyme within the Type II pneumocyte suggests that the cells within the lung itself are capable of producing degradative enzymes in this disease process.

Adult↗

PubMed2001

Altered GalNAc-alpha-2,6-sialylation compartments for mucin-associated sialyl-Tn antigen in colorectal adenoma and adenocarcinoma.

Sialyl-Tn (STn), a mucin-associated disaccharide antigen carried by apomucins such as MUC2, plays an important role in tumor biology. However, little is known about the subcellular localization and compartments involved in STn synthesis. In this study we used immunoelectron microscopy to localize STn and MUC2 apomucin in human colorectal tissues. MUC2 apomucin was localized predominantly in the rough endoplasmic reticulum (RER) in normal colorectal mucosa (n=6), colorectal adenoma (n=8), and colorectal adenocarcinoma (n=10). STn, recognized by monoclonal antibody TKH2, was not readily detectable in normal colorectal mucosa but becomes manifest in both trans-Golgi apparatus and mucin droplets in colorectal adenoma. In colorectal adenocarcinoma, STn was localized not only in late but also in early Golgi compartments, and particularly in some RER lumens. Furthermore, electron microscopic in situ hybridization revealed that gold particles representing MUC2 mRNA are primarily localized over the RER. Our findings indicate that in colorectal adenoma STn sialylation takes place in the trans-Golgi apparatus, whereas in colorectal cancer STn sialylation occurs in all the Golgi compartments and in the RER.

Adenocarcinoma↗

PubMed2001

Gene expression profiles in Ciona intestinalis tailbud embryos.

A set of 3423 expressed sequence tags derived from the Ciona intestinalis tailbud embryos was categorized into 1213 independent clusters. When compared with DNA Data Bank of Japan database, 502 clusters of them showed significant matches to reported proteins with distinct function, whereas 184 lacked sufficient information to be categorized (including reported proteins with undefined function) and 527 had no significant similarities to known proteins. Sequence similarity analyses of the 502 clusters in relation to the biosynthetic function, as well as the structure of the message population at this stage, demonstrated that 390 of them were associated with functions that many kinds of cells use, 85 with cell-cell communication and 27 with transcription factors and other gene regulatory proteins. All of the 1213 clusters were subjected to whole-mount in situ hybridization to analyze the gene expression profiles at this stage. A total of 387 clusters showed expression specific to a certain tissue or organ; 149 showed epidermis-specific expression; 34 were specific to the nervous system; 29 to endoderm; 112 to mesenchyme; 32 to notochord; and 31 to muscle. Many genes were also specifically expressed in multiple tissues. The study also highlighted characteristic gene expression profiles dependent on the tissues. In addition, several genes showed intriguing expression patterns that have not been reported previously; for example, four genes were expressed specifically in the nerve cord cells and one gene was expressed only in the posterior part of muscle cells. This study provides molecular markers for each of the tissues and/or organs that constitutes the Ciona tailbud embryo. The sequence information will also be used for further genome scientific approach to explore molecular mechanisms involved in the formation of one of the most primitive chordate body plans.

Animals↗

PubMed2001

Nuclear deviation in hepatic parenchymal cells on sinusoidal surfaces in Arctic animals.

In normal rat and human, most of the nuclei of hepatic parenchymal cells are centrally located in the cytoplasm. However, it is reported that the nuclei of hepatic parenchymal cells are situated at a deviated position on sinusoidal surfaces under pathological situations such as chronic hepatitis, hepatocellular carcinoma, adenomatous hyperplasia, or regeneration. During a study on the mechanism of extreme vitamin A-accumulation in hepatic stellate cells of arctic animals including polar bears, arctic foxes, bearded seals, and glaucous gulls, we noticed that these arctic animals displayed the nuclear deviation in hepatic parenchymal cells on sinusoidal surfaces. In this study, we assessed the frequency of hepatic parenchymal cells showing the nuclear deviation on the sinusoidal surfaces in arctic animals. A significantly higher frequency of the nuclear deviation in hepatic parenchymal cells was seen in polar bears (89.8+/-3.4%), arctic foxes (68.6+/-10.5%), bearded seals (63.6+/-8.4%), and glaucous gulls (24.2+/-5.8%), as compared to that of control rat liver (9.8+/-3.5%). However, no pathological abnormality such as fibrosis or necrosis was observed in hepatic parenchymal and nonparenchymal cells of arctic animals, and there were no differences in the intralobular distribution of parenchymal cells displaying the nuclear deviation in the livers from either arctic animals and control rats. The hepatic sinusoidal littoral cells such as stellate cells or extracellular matrix components in the perisinusoidal spaces may influence the nuclear positioning and hence the polarity and intrinsic physiological function of parenchymal cells.

Animals↗

PubMed2001

Functional analysis of the iron(II) etiocorrphycene incorporated in the myoglobin heme pocket.

The iron(III) complex of 2,7,12,17-tetraethyl-3,6,11,18-tetra-methylcorrphycene, an isomeric heme, was complexed with apomyoglobin to examine the ligand binding ability of the novel macrocycle under physiological conditions. The reconstituted holoprotein was found to be functionally active at pH 7.4 and 20 degrees C and to bind oxygen and carbon monoxide reversibly with a half-saturation pressure at 6.7 and 3.5mmHg, respectively. Equilibrium affinities for these ligands are one to two orders of magnitude lower than those reported for native myoglobin. The functional anomaly was ascribed to the geometric and electronic strain on the iron(II) atom in the trapezoidal coordination core of corrphycene.

Heme↗

PubMed2001

Lipid peroxidation may predict restenosis after coronary balloon angioplasty.

The present study assessed whether lipid peroxidation in plasma might predict restenosis after coronary balloon angioplasty. A total of 87 patients, who had undergone successful coronary balloon angioplasty using standard techniques, were enrolled. Fasting blood samples before the intervention were measured for plasma levels of thiobarbituric acid reactive substances (TBARS, an indicator of lipid peroxidation). Angiography was carried out before and 15 min after angioplasty, and at follow-up (4 months after angioplasty), and evaluated using a quantitative approach. There were 23 patients with restenosis (group R) and 64 patients without restenosis (group N) after coronary balloon angioplasty. The plasma TBARS level (mean+/-SEM) of 4.3+/-0.1 micromol/L in group R was significantly higher than that of 3.2+/-0.1 micromol/L in group N (p<0.01). There were no significant differences in other parameters, including plasma lipid levels, between the 2 groups. The plasma level of TBARS positively correlated with lumen loss of the coronary artery at the time of follow-up angiography (r=0.57, p<0.01). Our results suggest that oxidative stress contributes to restenosis and indicate that an elevated plasma level of TBARS may be a reliable predictor of restenosis.

Aged↗

PubMed2001

Effects of dehydroepiandrosterone on oleic acid formation in the liver of rats, mice and guinea pigs.

The purpose of the present study is to answer the question of whether there is a species difference in the effects of a pharmacological dose of dehydroepiandrosterone (DHEA) on the enzymes that participate in oleic acid (18:1) formation in the liver. Feeding a diet containing 0.5% (w/w) DHEA for 14 days markedly increased the activities of acyl-coenzyme A (CoA) synthetase, palmitoyl-CoA chain elongase and stearoyl-CoA desaturase in the liver of rats and mice. These enzyme activities, however, were not changed by DHEA in guinea pigs. The treatments of rats and mice with DHEA markedly increased proportions of 18:1 in hepatic lipids, especially phosphatidylcholine (selectively at C-2 position), triacylglycerol and cholesterol ester. DHEA caused no significant changes in acyl compositions of hepatic lipids of guinea pigs. The levels of DHEA or dehydroepiandrosterone sulfate (DHEAS) were markedly increased in serum and livers by DHEA administration to rats, mice and guinea pigs. High correlations were observed between hepatic levels of DHEA or DHEAS and stearoyl-CoA desaturase activities in rats. These results indicate that there are species differences in the inducing effects of DHEA or DHEAS on hepatic formation of 18:1 and that guinea pigs lack the machinery to induce the enzymes.

Acetyltransferases↗

PubMed2001

Rapid degradation of the silkworm diapause hormone by trypsin and its suppression by VAP-map, a synthetic analog of the cuticular peptide of silkworm, Bm ACP-6.7 (VAP-peptide).

Very fast tryptic degradation of the silkworm diapause hormone was found and the degradation pathway was analyzed by moderating the reaction conditions. It proceeded via cleavage at Arg23 and finally at Arg15 of DH. As the C-terminal structure of DH was essential for exhibiting bioactivity, the first cleavage caused rapid inactivation of the hormone. This tryptic digestion was strongly suppressed by adding VAP-map, a synthetic analog of the cuticular peptide of silkmoths, Bm ACP-6.7 (VAP-peptide), which is a natural synergist of DH. VAP-map suppressed the enzymic reaction by interacting with the substrate, but not with the enzyme.

Amino Acid Sequence↗

PubMed2001

Isolation and characterization of the novel lipophilic protein, Pb CP-12.7, from the shell of the pink shrimp, Pandalus borealis.

Past research on diapause-inducing substances of the silkworm has isolated an extremely lipophilic peptide and demonstrated its unique characteristics. In the present work, similar lipophilic proteins were searched for in the shell of the shrimp, Pandalus borealis, and one novel protein, Pb CP-12.7, was isolated. Its structure comprising 126 amino acids was revealed by a combination of a sequence analysis and the enzymic fragmentation technique. Pb CP-12.7 is unique in that it was insoluble in neutral-slightly basic water, but highly soluble in some organic solvents. It contained an abundance of hydrophobic amino acids and repeating sequences. In addition, it was adsorbed to chitin, a major component of the shell of the shrimp.

Adsorption↗

PubMed2001

Association between blood pressure and insulin resistance in obese females during weight loss and weight rebound phenomenon.

The purpose of this study was to investigate the effect of weight loss on blood pressure and its related variables in moderately obese Japanese females, including an investigation of the rebound phenomenon. Study I examined the effects of weight loss on blood pressure in 138 moderately obese, nondiabetic females (BMI 29.3+/-0.3 kg/M2; age, 46.3+/-0.8 years) during a 3-month therapeutic dietary and exercise program. Study II investigated the effect of weight rebound on blood pressure over an additional 21 months of exercise in 48 subjects from Study I subjects. After 3 months, the BMI significantly decreased to 27.9+/-0.3 kg/m2. Abdominal total fat, visceral fat (V), and subcutaneous fat (S) also decreased significantly. In addition, the summation of insulin (sigmaIRI), plasma glucose (sigmaPG) and HOMA during 75 g oral glucose tolerance test also all significantly decreased. Significant decreases in both the SBP and DBP were observed after the 3 month weight reduction program. Multiple regression analysis revealed that the reduction in SBP was significantly and positively associated with the reduction in log sigmaIRI and the reduction in log 24h-urinary norepinephrine excretion at the end of Study I. The DBP showed a significantly positive association with the log sigmaIRI. With regard to the weight rebound phenomenon, Study II showed that the SBP, DBP and sigmaIRI all increased significantly, and a positive correlation was observed between the changes in the SBP and those in the log sigmaIRI. However, no such correlation was observed regarding the abdominal total fat and visceral fat during both periods. These results suggest that weight loss therefore caused the BP to decrease due to both an improvement in hyperinsulinemia and a decrease in the adrenergic activity which may be involved in the urinary catecholamine. As a result, hyperinsulinemia is thus considered to play an important role in the pathogenesis of blood pressure due to obesity not only during weight loss, but also during the weight rebound phenomenon.

Blood Glucose↗

PubMed2001

Invasive pulmonary aspergillosis in a puerperant with drug-induced agranulocytosis.

Invasive pulmonary aspergillosis (IPA) is an acute infection of Aspergillus species to the lungs. It generally occurs in immunocompromised hosts, especially with neutropenia. We report a 30-year-old puerperant, who developed IPA from agranulocytosis. She had been treated for threatened labor with ritodrine and cefepime, one of which induced agranulocytosis. After vaginal delivery of twins, pneumonia emerged in the right lower lobe. She was diagnosed to have IPA according to the halo sign on computed tomography (CT) and positive circulating antibody against Aspergillus, and was treated successfully with oral itraconazole followed by surgical resection. It is important to note that IPA might arise in otherwise immunocompetent hosts when neutropenia is long-standing.

Adult↗

PubMed2001

Inflammatory pseudotumor of the liver complicated with recurrent gouty arthritis.

Inflammatory pseudotumor (IPT) of the liver is a rare benign lesion of unknown etiology and is often accompanied by fever. Unexplained persistent fever unresponsive to antibiotics developed in a 70-year-old man suffering from intractable recurrent gouty arthritis. 67Ga-scintigraphy disclosed intense focal uptake in the upper abdomen. The lesion in the left lobe of the liver was an ill-defined hypodensity mass on computed tomographic scan and was enhanced on dynamic magnetic resonance imaging. The tumor was surgically removed and a diagnosis of IPT was made. Fever and arthritis resolved completely after surgery. Possible interaction between IPT of the liver and gouty arthritis was suggested.

Aged↗

PubMed2001

Brain metastases of malignant melanoma showing unbalanced whole arm chromosomal translocations der (8; 14) (q10; q10) and der (11; 15) (q10; q10) in a Japanese patient.

Since malignant melanoma is a rare malignancy in Japan, little is known about the cytogenetic abnormalities in Japanese patients. We report a case of malignant melanoma showing complex chromosomal abnormalities. A 70-year-old woman was admitted to our hospital because of anorexia, delirium, and right hemiplegia. Cranial CT disclosed several metastatic brain tumors. Multiple subcutaneous and intra-abdominal metastases were also found. A diagnosis of metastatic malignant melanoma was made by biopsy of a subcutaneous tumor. Chromosomal analysis of the tumor cells disclosed complex karyotypic abnormalities including novel unbalanced whole arm translocations der (8; 14) (q10; q10) and der (11; 15) (q10; q10).

Aged↗

PubMed2001

Epstein-Barr virus-associated gastric cancer in a patient with dermatomyositis.

A 59-year-old man was admitted presenting systemic rash and muscle weakness. He was diagnosed to have dermatomyositis and a check was made for internal malignancy. Gastrointestinal endoscopy revealed a Borrmann type II tumor on the middle body of the stomach. Biopsy specimens showed a well differentiated adenocarcinoma, and total gastrectomy was performed. The final diagnosis was moderately differentiated adenocarcinoma invading into the proper muscular layer, with metastases to regional lymph nodes. Most of the neoplastic cells were shown to be positive for Epstein-Barr virus by means of EBV-encoded RNA in situ hybridization. The symptoms of dermatomyositis disappeared completely after surgery.

Adenocarcinoma↗

PubMed2001

[Case of protein-losing gastroenteropathy associated with scleroderma in which central serous chorioretinopathy developed].

A 44-year-old woman noticed edema of the lower limbs in May 1999 and visited our hospital in September 1999 to undergo further examination. On admission, severe hypoalbuminemia (1.9 g/dl) was detected with a negative urinary protein level. Protein leakage into the gastrointestinal tract and deposition of immune complex in the colonic mucosa were shown by the fluorescent antibody method. In addition, anti-centromere antibody, sclerodactyly, and findings indicative of histological sclerotic changes on a skin biopsy were observed. These findings supported a diagnosis of protein-losing gastroenteropathy complicated by scleroderma. Administration of oral corticosteroids was begun one month after admission and the patient experienced diminished visual acuity immediately after steroid pulse therapy in November. Central serous chorioretinopathy (CSC) was diagnosed at the Department of Ophthalmology of our hospital, and the administration of corticosteroids was suspected as a possible cause of CSC. Considering the severity of hypoproteinemia, the corticosteroid treatment was continued despite corticosteroids being strogly suspected as the primary cause of CSC. A complete disappearance of CSC was achieved in 30 days after the onset of symptoms despite continuation of the steroid therapy, and her serum albumin and complement levels both normalized. We concluded that damage to the retinal pigment epithelium secondary to the vascular lesion at the choroidal level plays a causative role in CSC. In the present case, the findings suggested that the deposition of immune complex in choroidal tissues as well as the gastrointestinal tract caused hyperpermeability of choroidal vessels and led to the development of CSC.

Adult↗

PubMed2001

[Brain abscess developed five years after splenectomy in a patient with idiopathic thrombocytopenic purpura].

The increased susceptibility to infection following splenectomy has been well documented. We report here, a case of brain abscess developed five years after splenectomy in a patient with idiopathic thrombocytopenic purpura (ITP). A 65-year-old woman was admitted to our hospital because of fever, mental disorientation, and weakness in August, 1999. She had been followed with diagnoses of essential hypertension and type 2 diabetes mellitus (DM) since 1988. The patient was diagnosed as having ITP in 1992, and then underwent splenectomy in 1994. Monoclonal gammopathy of undetermined significance (MGUS) of IgG, lambda type was found in February 1999. Though high grade fever persisted after admission, blood cultures were negative. Antibiotics were given without a satisfactory effect. Right hemiparesis and worsening of consciousness developed subsequently. Contrast enhanced cranial computed tomography (CT) disclosed a ringed enhanced low density mass in the left parieto-occipital lobe compatible with a diagnosis of brain abscess. Surgical drainage was performed and 20 ml of pus was obtained. No primary infectious focus of the brain abscess was detected with intensive examinations.

Aged↗

PubMed2001

[Association of idiopathic thrombocytopenic purpura and type 1 diabetes mellitus in a patient with sarcoidosis].

Occurrence of autoimmune diseases with sarcoidosis is well known. However, a case in which more than one of these diseases coexist with sarcoidosis is rare. We present a young man with suspected sarcoidosis, complicated by idiopathic thrombocytopenic purpura (ITP) and type 1 A diabetes mellitus (DM). A 21-year-old man was admitted to our hospital because of thrombocytopenia, hyperglycemia, and bilateral hilar lymphadenopathy (BHL). Although a histological proof could not be obtained, the patient was considered to have sarcoidosis because 67-gallium scintigraphy disclosed "Lambda" and "Panda" signs which are highly specific for sarcoidosis. Type 1 A DM was also diagnosed as the patient had antiglutamic acid decarboxylase antibodies. The patient disclosed no hepatosplenomegaly or no lymphadenopathy and diagnosis of ITP was confirmed by bone marrow examination. High dose steroid was started as the thrombocytopenia progressed. The platelet number increased satisfactorily and shrinkage of BHL was also observed with the therapy.

Adult↗

PubMed2001

Natural killer activity and its changes among participants in a smoking cessation intervention program--a prospective pilot study of 6 months' duration.

We examined the effect of smoking cessation on natural killer (NK) activity of peripheral blood lymphocytes in terms of a prospective study of 27 Japanese subjects who participated in a smoking cessation intervention program. This program was delivered by means of group-counseling offering 7 sessions of about 2 hours over 6 months to help smokers to discontinue the habit. Thirteen subjects ceased smoking (quitters), while 14 continued to smoke (cigarette smokers). NK activity before the intervention was correlated positively with age (correlation coefficient=0.46, P<0.05). NK activity remained almost constant among quitters, comparing the activity before and after the intervention, while it decreased among cigarette smokers although it was not statistically significant. In the subgroup analysis, NK activity increased among those aged less than 65 years, or urine cotinine levels over 800 ng/ml before the intervention, especially among quitters, but there were no statistical significances. Multiple regression analysis showed changes in NK activity were correlated significantly only with age (standard regression coefficient=-0.44, P<0.05). These findings suggest that smoking cessation intervention programs might have been more effective for younger than elder subjects in consideration of NK activity.

Aged↗