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Biomedical subjects

K Maruyama

Publications and source records attributed to K Maruyama.

At least 37 records · Page 2Linked to original sources
PubMed2003

Nicotine applied by transdermal patch induced HSV-1 reactivation and ocular shedding in latently infected rabbits.

The identification of factors involved in herpes virus latency and reactivation is critical to a better understanding of the mechanisms essential to viral neuroinvasiveness and neurovirulence. Recurrent episodes of ocular herpes infections cause irreversible corneal scarring and are the primary cause of loss of vision due to an infectious agent in industrialized countries. In this study, we examined the ability of nicotine, a compound known to be involved in stress-associated immunomodulation and recognized as one of the most frequently used addictive agents, to induce ocular shedding in rabbits latently infected with herpes simplex virus type 1 (HSV-1) strain McKrae. New Zealand white rabbits latently infected with HSV-1 at 3-4 weeks post-inoculation were randomly divided into two groups. The corneas of all rabbits were free of lesions as verified by slit lamp biomicroscopy. One group received nicotine by transdermal patch (21 mg/day) for 20 days and the other group served as the control. Reactivation data were obtained by detection of virus in tear film collected by ocular swabbing performed concurrently with the administration of nicotine. Compilation of data from three separate experiments demonstrated that 16.5% (258/1560) of the swabs taken from rabbits treated with nicotine were positive for virus, compared with 8.3% (53/639) of swabs taken from controls. Rabbits receiving nicotine exhibited a significantly (P < 0.0001) higher rate of ocular shedding than controls. The concentration of nicotine in the serum was determined at various times (0-24 hrs) after new patch replacement. Peak (average) serum level of nicotine was obtained 8 hours after patch replacement and exhibited a broad range of values (0.233 microg/mL-6.21 microg/mL). These results suggest that an initial systemic exposure to nicotine significantly increases HSV-1 reactivation. Further studies are needed to reveal any effects of nicotine dependency and nicotine withdrawal on herpesvirus reactivation.

Administration, Cutaneous↗
PubMed2003

Impaired cardiac response to exercise in post-menopausal women: relationship with peripheral vascular function.

Endothelial dysfunction has been demonstrated in post-menopausal women. To assess the relationship between peripheral vascular reserve and cardiac function during exercise in post-menopausal women, 91 subjects, who had no ischaemic findings on myocardial SPECT, were assigned to four groups: pre-menopausal women (n=13), post-menopausal women (n=33), younger men aged < or =50 years (n=10), and older men aged >50 years (n=35). First-pass radionuclide angiography was performed before and during bicycle exercise to calculate ejection fraction (EF) and peripheral vascular resistance (VR). There were no differences in haemodynamic variables among the groups at baseline. The per cent increase in EF=(exercise EF - resting EF)x100/resting EF, and the per cent decrease in VR=(resting VR - exercise VR)x100/resting VR were depressed in the post-menopausal women (0.4+/-2% and 35+/-3%, respectively) compared to the pre-menopausal women (10+/-3% and 47+/-3%, respectively; P<0.05 each). Although the age dependent impairment is thought to cause this depression, neither the per cent increase in EF nor the per cent decrease in VR in the older men was significantly different from that in the younger men. Post-menopausal women exhibited depressed cardiac function during exercise, which may be related to the impairment of peripheral vascular function after menopause.

Adult↗
PubMed2003

Targeting of post-ischemic cerebral endothelium in rat by liposomes bearing polyethylene glycol-coupled transferrin.

To achieve an efficient delivery targeting to post-ischemic cerebral vascular endothelium, PEG-liposome conjugated with transferrin (Tf) (Tf-PEG-liposome) was intravenously administered to the rats after 90 min of transient middle cerebral occlusion. The expression of Tf receptor (TfR) in the cerebral endothelium increased with a peak at 1 day after the reperfusion and returned to the control level by 6 days. The Tf-PEG fluorescence was marginally detectable in sham control brain, but remarkably increased with a peak at 2 days, showing about 70% of TfR positive vascular endothelium double-labeled with Tf-PEG. These results indicate that the Tf-PEG-liposome could be utilized as an efficient drug delivery tool to the brain after stroke.

Animals↗
PubMed2002

Caspase-12 processing and fragment translocation into nuclei of tunicamycin-treated cells.

Excess endoplasmic reticulum (ER) stress induces processing of caspase-12, which is located in the ER, and cell death. However, little is known about the relationship between caspase-12 processing and cell death. We prepared antisera against putative caspase-12 cleavage sites (anti-m12D318 and anti-m12D341) and showed that overexpression of caspase-12 induced autoprocessing at D(318) but did not induce cell death. Mutation analysis confirmed that D(318) was a unique autoprocessing site. In contrast, tunicamycin, one of the ER stress stimuli, induced caspase-12 processing at the N-terminal region and the C-terminal region (both at D(318) and D(341)) and cell death. Anti-m12D318 and anti-m12D341 immunoreactivities were located in the ER of the tunicamycin-treated cells, and some immunoreactivities were located around and in the nuclei of the apoptotic cells. Thus, processing at the N-terminal region may be necessary for the translocation of processed caspase-12 into nuclei and cell death induced by ER stress. Some of the caspase-12 processed at the N-terminal and C-terminal regions may directly participate in the apoptotic events in nuclei.

Active Transport, Cell Nucleus↗
PubMed2002

Choledocholithiasis in an infant of extremely low birthweight.

A five-month-old infant of extremely low birthweight with choledocholithiasis is reported. A baby girl was delivered at 26 weeks gestation as a second twin, weighing 834 g. At 30 days of age, gallbladder stones were found by routine ultrasonography. She had vomiting at 157 days of age. Ultrasonography revealed calculi in the gallbladder and a dilated common bile duct. She was conservatively treated with scopolamine, antibiotics and dehydrocholic and ursodeoxycholic acids, and the calculi had disappeared by 189 days of age. Although conservative treatment succeeded in this patient, further cases should be analysed to establish how to manage choledocholithiasis in such small infants.

Dehydrocholic Acid↗
PubMed2002

Prognostic value of EEG depression in preterm infants for later development of cerebral palsy.

The aim of this study is to examine the most appropriate timing for EEG recordings in order to predict the risk of cerebral palsy (CP) on the basis of the degree of acute stage abnormalities (ASA) in preterm infants. We retrospectively investigated the correlation between the degree of ASA and psychomotor outcome of 295 infants born between 27 and 32 weeks of gestational age whose initial EEG recording was performed within 7 days of life. Forty-six infants were diagnosed as having CP at 18 months of corrected age, and most of them suffered from diplegia due to periventricular leukomalacia (PVL). The maximum degree of ASA correlated with a later development of CP and its severity. Correlation between the degree of ASA and the severity of CP was highest on day 1 - 2, but this tendency was less clear after day 3. Specificity and negative predictive value were generally high within the first 7 days of life. But sensitivity was markedly decreased after day 3, and positive predictive value was highest on day 2. An EEG on day 1 or 2 will be useful in order to predict developmental outcome of preterm infants on the basis of the grade of ASA.

Acute-Phase Reaction↗
PubMed2002

Microscopic response of radiation on imaging plates.

The microscopic response of alpha particles on an imaging plate was studied experimentally. It is proved that a single alpha event can be discriminated from background signals and be recorded on the imaging plate. The spatial resolution of the dose distribution was found to be 43 +/- 2 microns when alpha particles were injected perpendicularly. The observed output signals are well described by the deposited energy.

Alpha Particles↗
PubMed2002

14 C-deoxyglucose imaging overestimates myocardial viability in subacute infarction of rats.

Clinical studies using 18F-fluorodeoxyglucose suggest that this tracer may overestimate myocardial viability. This study aimed to elucidate whether 2-deoxyglucose accurately indicates myocardial viability at the early phase of myocardial infarction. Autoradiography with 14C-deoxyglucose was performed in fasting rats whose left coronary artery was occluded for 60 min and then reperfused. 14C-deoxyglucose was injected 30 min after the reperfusion (acute; n=10) or 1 week later (subacute; n=9). Infarction and risk areas were identified by triphenyl tetrazolium chloride or haematoxylin-eosin staining and methylene blue, respectively. Immuno-histochemical staining using anti-glucose transporter 1 and 4 antibodies was performed. At the acute stage, the uptake of deoxyglucose was consistent with the grade of anti-glucose transporter 4 expression. At the subacute stage, the uptake of deoxyglucose in poorly viable myocardium (543.4+/-343.7%: normalized with the uptake at the right ventricle) as well as in the viable one (335.2+/-149.8%) in the risk area was significantly greater than that in the remote area (116.4+/-94.9%, P<0.01). Anti-glucose transporter 1 was expressed in the poorly viable area where inflammatory cells infiltrated. It is concluded that deoxyglucose uptake by inflammatory cells which express anti-glucose transporter 1 causes overestimation of myocardial viability at subacute stage.

Acute Disease↗
PubMed2002

Early-onset group B streptococcal sepsis in a preterm infant with Kostmann syndrome.

UNLABELLED: A preterm infant died of group B streptococcal sepsis 7 h after birth. The infant's complete blood count showed total agranulocytosis. Histopathology of the major organs showed significant bacterial invasion without infiltration of polymorphonuclear leucocytes. Examination of the bone marrow revealed normal cellularity of the granulocyte precursors with arrested maturation. These findings are consistent with Kostmann syndrome. CONCLUSION: It is suggested that in patients with deteriorating early-onset infection, underlying congenital abnormalities in host defence, such as Kostmann syndrome, should be considered.

Age of Onset↗
PubMed2002

Guillain-Barré syndrome associated with central nervous system lesions.

We report the clinical course, and neurophysiological and neuroimaging findings of a patient with Guillain-Barré syndrome associated with central nervous system lesions. During a course of intravenous immunoglobulin therapy, she had headache with meningism. Cerebral magnetic resonance imaging showed lesions in both frontal and right occipital lobes. Cerebrospinal fluid showed a raised protein concentration accompanied by mild pleocytosis. Her symptoms resolved within two months. Subsequent magnetic resonance imaging revealed cavity formation in the deep white matter and atrophic changes in the right occipital lobes.

Brain Diseases↗
PubMed2002

Correlation of inhaled nitric-oxide induced reduction of pulmonary artery pressure and vascular changes.

The purpose of the present study was to determine the relationship between hypertensive pulmonary vascular remodelling and the changes in mean pulmonary artery pressure (mPAP) during low-dose nitric oxide (NO) inhalation. Rats were exposed to chronic hypobaric hypoxia (air at 50.5 kPa (380 mmHg), 10% oxygen, for 5-29 days) to induce chronic pulmonary hypertension (PH) with pulmonary vascular structural changes. After the chronic hypoxic exposure, the rats had an indwelling pulmonary artery catheter inserted and changes in mPAP with NO were correlated to morphometrical analysis of pulmonary vascular changes. All concentrations of inhaled NO (0.1-2.0 parts per million) reduced mPAP with a similar per cent reduction from baseline mPAP in PH rats, while no changes were observed in control rats. During NO inhalation in PH rats, the absolute value of the decrease in mPAP, but not per cent reduction in mPAP, significantly correlated with baseline mPAP, the percentage of muscularised arteries at the alveolar wall level and at the alveolar duct level, and the per cent medial wall thickness of muscularised arteries. In the chronic hypoxic pulmonary hypertension model, the severity of pulmonary vascular remodelling did not alter the reactivity of the pulmonary arteries to nitric oxide and might, in part, determine the magnitude of nitric-oxide induced absolute reduction in mean pulmonary artery pressure.

Administration, Inhalation↗
PubMed2001

Endogenous melanin-concentrating hormone receptor SLC-1 in human melanoma SK-MEL-37 cells.

Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that regulates several physiological functions. The orphan G protein-coupled receptors SLC-1 and MCHR2 were recently found to bind MCH with high affinity. We show here that the human melanoma cell line SK-MEL-37 expresses SLC-1 mRNA but not MCHR2 by RT-PCR analysis and immunofluorescence studies. Using Chinese hamster ovary cells and 293 cells overexpressing SLC-1 by cDNA transfection, it was shown that SLC-1 coupled to both G alpha(i)/G alpha(o) and G alpha(q) proteins. In SK-MEL-37 cells, MCH inhibited forskolin-stimulated cyclic AMP accumulation and induced mitogen-activated protein kinase (MAPK) in a pertussis toxin-(PTX)-sensitive manner. The MAPK activity leads to the production of phosphorylated forms of p42/p44 MAPK. However, an increase in the intracellular free Ca(2+) concentration was not elicited by MCH in SK-MEL-37 cells. These results show that SLC-1 is coupled only to PTX-sensitive G alpha(i)/G alpha(o) in SK-MEL-37 cells. This study provides for the first time a skin-derived cellular model to analyze the molecular mechanism of the MCH signaling pathway.

Animals↗
PubMed2001

Absence of exacerbation of myocardial stunning in anesthetized dogs treated with KAD-1229, a novel hypoglycemic agent.

The effect of (+)-momocalcium bis[(2S,3a,7a-cis)-alpha-benzylhexahydro-gamma-oxo-2-isoindolinebutyrate]dihydrate (KAD-1229), a novel hypoglycemic agent with a chemical structure different from that of the sulfonylureas, on myocardial stunning was assessed in anesthetized dogs by comparison with that of glibenclamide, a sulfonylurea. Even though their hypoglycemic effects were of similar magnitude, glibenclamide (1 mg/kg, i.v.), but not KAD-1229, exacerbated the myocardial stunning induced by occlusion/reperfusion of the descending coronary artery. In a receptor-binding experiment, unlabeled glibenclamide completely inhibited [(3)H]glibenclamide binding to the myocardium, but KAD-1229 did not. These results suggest that the difference in binding properties of KAD-1229 and glibenclamide toward cardiac sulfonylurea receptors is one of the causes of their different effects on myocardial stunning. It is likely that KAD-1229 is highly specific for pancreatic sulfonylurea receptors and is speculated to be a safer hypoglycemic agent than, at least, glibenclamide.

ATP-Binding Cassette Transporters↗
PubMed2001

Association of maspin expression with the malignancy grade and tumor vascularization in breast cancer tissues.

Maspin belongs to a tumor suppressing protein which is usually expressed highly in myoepithelial cells, and is significantly downregulated in breast cancer cells. We focused on identifying the correlation between maspin expression and the clinicopathological features of human breast cancer tissues using immunohistochemistry. There was a significant correlation in that maspin-positive tumor specimens showed a low pathological grade of malignancy, such as a lower infiltration of the tumor into the surrounding tissue and a downregulation of c-erbB2 expression. Moreover, maspin-positive cases showed a significant decrease in tumor vessels positively stained with anti-factor VIII-related antigen antibody. These results suggest that maspin production in myoepithelial cells could downregulate the malignant phenotype of breast cancer.

Biomarkers, Tumor↗
PubMed2001

Invertebrate connectin spans as much as 3.5 microm in the giant sarcomeres of crayfish claw muscle.

In crayfish claw closer muscle, the giant sarcomeres are 8.3 microm long at rest, four times longer than vertebrate striated muscle sarcomeres, and they are extensible up to 13 microm upon stretch. Invertebrate connectin (I-connectin) is an elastic protein which holds the A band at the center of the sarcomere. The entire sequence of crayfish I-connectin was predicted from cDNA sequences of 53 424 bp (17 352 residues; 1960 kDa). Crayfish I-connectin contains two novel 68- and 71-residue repeats, and also two PEVK domains and one kettin region. Kettin is a small isoform of I-connectin. Immunoblot tests using antibody to the 68-residue repeats revealed the presence of I-connectin also in long sarcomeres of insect leg muscle and barnacle ventral muscle. Immunofluorescence microscopy demonstrated that the two repeats, the long spacer and the two PEVK domains contribute to sarcomere extension. These regions rich in charged amino acids, occupying 63% of the crayfish I-connectin molecule, may allow a span of a 3.5 microm distance as a new class of composite spring.

Amino Acid Sequence↗
PubMed2001

Immunohistochemically detected micrometastases of the lymph nodes in patients with gastric carcinoma.

BACKGROUND: Lymph node status is a major determinant of disease recurrence after patients undergo curative resection for gastric carcinoma. A proportion of patients without lymph node metastasis develop systemic recurrences. Recent studies in a range of solid tumors have found a high incidence of micrometastases in the regional lymph nodes of patients with apparently negative lymph nodes. In patients with breast and colorectal carcinoma, the presence of micrometastases has been associated with a poorer prognosis. In patients with gastric carcinoma, the significance of micrometastases in lymph nodes remains controversial. Most published reports on this subject suffer from the problems of small sample size and selection bias. METHODS: One hundred seven patients with pathologic T2N0M0 (tumor invades muscularis propria or subserosa [T2], no regional lymph node metastasis [N0], and no distant metastasis [M0]; pT2N0M0) gastric carcinoma who underwent gastric resection between 1984 and 1990 at the National Cancer Center Hospital were studied. Two consecutive sections were newly prepared from each lymph node for hematoxylin and eosin staining and immunohistochemical staining (IHC) with antibody against cytokeratin. Associations between clinicopathologic factors and the presence of micrometastases as well as micrometastases and survival were sought. RESULTS: Micrometastases were identified in 38 of 107 patients (35.5%) and in 87 of 4484 lymph nodes (1.94%) by IHC. The incidence of micrometastases was significantly higher in patients with infiltrative tumors than in patients with expansive, growing tumors (P = 0.02). Other clinicopathologic findings had no statistically significant correlation with the incidence of micrometastases. The 5-year survival rates of patients with and without micrometastases were 94% and 89%, respectively. Similarly, the 10-year survival rates were 79% and 74%, respectively. The survival curves of patients with or without micrometastasis were nearly superimposed (P = 0.86). CONCLUSIONS: The presence of immunohistochemically detected micrometastases in the regional lymph nodes did not affect the survival of Japanese patients with pT2N0M0 gastric carcinoma who had undergone gastrectomy with D2 lymph node dissection.

Adult↗
PubMed2001

Human wild presenilin-1 mimics the effect of the mutant presenilin-1 on the processing of Alzheimer's amyloid precursor protein in PC12D cells.

Most familial early-onset Alzheimer's disease (FAD) is caused by mutations in the presenilin-1 (PS1) gene. Abeta 42 is derived from amyloid precursor protein (APP) and increased concentrations are widely believed to be a pathological hallmark of abnormal PS function. Thus, the interaction between PS1 and APP is central to the molecular mechanism of AD. To examine the effect of wild-type human PS1 on rat APP metabolism, we made several PC12D cell lines that expressed human wild or mutant PS1, and analyzed the processing of endogenous rat APP and the intracellular gamma-secretase activity. We found the ratio of Abeta 42/Abeta 40 increased in PC12D cells expressing wild-type human PS1. These changes were identical to those found in PC12D cells expressing human PS1 bearing the A260V mutation. These results suggest that APP metabolism is physiologically regulated by the PS1 and that loss of normal PS1 affects gamma-secretase activity.

Alzheimer Disease↗