Biomedical subjects

K Kitamura

Publications and source records attributed to K Kitamura.

At least 127 records · Page 7Linked to original sources

PubMed2000

Cytologic differential diagnosis among reactive mesothelial cells, malignant mesothelioma, and adenocarcinoma: utility of combined E-cadherin and calretinin immunostaining.

BACKGROUND: The differential diagnosis between reactive mesothelial cells (RMs), malignant mesotheliomas (MMs), and adenocarcinomas (ACs) is often difficult in cytologic specimens, and the utility of various immunohistochemical markers have been explored. Because recent immunohistologic studies have suggested that E-cadherin (E-cad) and calretinin (Cal) may be useful markers for epithelial and mesothelial differentiations, respectively, the authors investigated their utility in cytologic diagnosis. METHODS: In this retrospective study, immunostaining was performed on smears retrieved from Papanicolaou-stained slides of effusions using the labeled streptavidin-biotin method. Sixteen cases of RM, 9 cases of MM, and 52 cases of AC from various sites, including 13 pulmonary primaries, were examined with primary antibodies against E-cad and Cal. RESULTS: The positive rates for E-cad and Cal, respectively, were as follows: RM, 0/16 (0%) and 16/16 (100%); MM, 9/9 (100%) and 8/8 (100%); and AC, 45/52 (86.5%) and 0/51 (0%). The E-cad expression by neoplastic cells was strongest in the intercellular junctions, and poorly differentiated neoplastic cells in the single cell form showed the weakest expression. CONCLUSIONS: In contrast to the results of previous immunohistochemical studies, the current study indicates that MMs constantly express E-cad, whereas RMs lack its expression in cytologic specimens, which would be useful in the differential diagnosis between the two. On the other hand, E-cad expression is not reliable for distinguishing AC from MM. The Cal expression can be a very useful marker for the distinction between AC and the mesothelial lineage. The combined immunostaining for E-cad and Cal has utility in differential diagnosis among RM, MM, and AC.

Adenocarcinoma↗

PubMed2000

Quasinondestructive holographic recording in photochromic LiNbO3

We have observed quasinondestructive holographic storage with a continuous-wave laser at lambda = 532 nm in near-stoichiometric LiNbO3 doped with Tb and Fe. This crystal showed an exceptionally long grating decay time and also exhibited a fast color change upon exposure to ultraviolet (UV) light. It was demonstrated that the grating recorded from the UV-exposed, colored state can be continuously read out over 9 h at a reading intensity as high as 8 mW/cm(2). In addition, the written grating could be easily erased with UV illumination which returned the crystal back to the original colored state.

Journal Article↗

PubMed2000

Molecular detection of disseminated cancer cells in the peripheral blood and expression of sialylated antigens in colon cancers.

BACKGROUND AND OBJECTIVES: To improve the survival rate of patients with colon cancer, liver metastases must be eradicated in a clinically occult state. This study was designed to find a predictor for potential liver metastases or micrometastases in colon cancer. METHODS: Peripheral blood samples and tumor specimens were obtained from 36 patients with colon cancers. The blood samples were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, and the expression of sialylated carbohydrates was also investigated in the tumors immunohistochemically. RESULTS: A carcinoembryonic antigen (CEA)-specific signal in the blood was detected in 9 of 12 (75%) patients with liver metastasis and in 8 of 24 (33%) patients without liver metastasis, respectively (P < 0.05). The positive rates of sialyl Lewis A (sLeA) and sialyl Lewis X (sLeX) were 36.3% and 40% in tumors without liver metastasis vs. 58.3% and 100% with liver metastasis, respectively. Within a year after surgery, liver metastases became clinically evident in three of the four patients without liver metastasis who showed a CEA-positive signal in their blood preoperatively and who had tumors with a strong expression of sLeX. CONCLUSIONS: A combination of both markers may provide prognostic information for liver metastases in colon cancer.

Colonic Neoplasms↗

PubMed2000

Pharmacologic doses of interleukin 8 suppositories induce follicular maturation in rabbits.

Interleukin 8 (IL-8) is a neutrophil chemoattractant/activating factor that plays a role in the ovarian physiology leads to investigate the effects of IL-8 on follicular maturation. Experiments were conducted using suppositories containing 100 ng, 200 ng, 400 ng IL-8, 500 microl Witepsol-base (control), human menopausal gonadotropin (im) and conjugate of fluorescein isithiocyanate-labelled IL-8. The levels of IL-8 in ovarian fluid were also measured. Histology of ovaries treated with 200 ng IL-8 showed large antral follicles filled with follicular fluid. The theca layer was divided into an interna and an externa with large extracellular spaces. The granulosa cells were loosened and appeared to be detaching from the granulosa layer. Neutrophils were localized predominantly in the theca and medulla (P<0.0001, P<0.004), and relative collagen concentration was significantly decreased in ovaries of 200 ng IL-8 (P<0.0001) compared with controls. The IL-8 was detected in ovarian fluid after 6 h (P<0.0001), 12 h (P<0.001), and 18 h (P<0.01) compared with 0 h. Fluorescein isithiocyanate-labelled IL-8 conjugate was seen in the follicular wall and endometrium. We conclude that pharmacological dosage of exogenous IL-8 exerts an effect on follicular maturation through granulocyte chemotaxis and activation.

Animals↗

PubMed2000

Effects of peptidase inhibitors on anti-nociceptive action of dynorphin-(1-8) in rats.

Previous in vitro studies showed that the degradation of dynorphin-(1-8) [dyn-(1-8)] by cerebral membrane preparations is almost completely prevented by a mixture of three peptidase inhibitors (PIs), amastatin, captopril and phosphoramidon. In the present investigations, effects of the three PIs on the anti-nociception induced by the intra-third-ventricular (i.t.v.) administration of dyn-(1-8) were examined. The inhibitory effect of dyn-(1-8) on the tail-flick response was increased more than 100-fold by the i.t.v. pretreatment of rats with the three PIs. The inhibition produced by dyn-(1-8) in rats pretreated with any combination of two PIs was significantly smaller than that in rats pretreated with three PIs, indicating that any residual single peptidase could inactivate significant amounts of dyn-(1-8). The antagonistic effectiveness of naloxone, a relatively selective mu-opioid antagonist, indicates that dyn-(1-8)-induced inhibition of tail-flick response in rats pretreated with three PIs is mediated by mu-opioid receptors. Furthermore, mu-receptor-mediated inhibition induced by dyn-(1-8) was significantly greater than that produced by [Met5]-enkephalin in rats pretreated with three PIs. The data obtained in the present investigations together with those obtained in previous studies strongly indicate that dyn-(1-8) not only has well-known kappa-agonist activity but also has high mu-agonist activity.

Analgesics, Opioid↗

PubMed2000

Presence and possible role of the spliced isoform of the P2X1 receptor in rat vascular smooth muscle cells.

An alternatively spliced isoform of the P2X1 receptor (P2X1a) was cloned from rat mesenteric artery. The spliced isoform does not have the 27 amino acids that are in the middle of the putative extracellular loop domain of the P2X1 original subunit (P2X1). Reverse transcriptase polymerase chain reaction (RT-PCR) revealed co-localization of P2X1a mRNA and P2X1 mRNA in vascular and other smooth muscle tissues and heart, but not in the spinal cord. In HEK293 cells transfected with P2X1 cDNA, ATP (1 microM) evoked an inward current which strongly desensitized, and an intense signal for GFP (green fluorescent protein) fused with P2X1 was detected at the membrane. Neither of these results was obtained in HEK293 cells expressing P2X1a alone. The fluorescent GFP signal was detected at the membrane when GFP-fused P2X1a was co-expressed with P2X1, and no significant difference in the ATP-activated current was noted between cells expressing P2X1 and those coexpressing P2X1 and P2X1a. These results indicate that the 27-amino-acid sequence (175-201) is important for protein trafficking to the membrane and for the formation of a functional P2X1 receptor. Our results also show that P2X1a is transported to the membrane when P2X1a is co-expressed with P2X1, although the co-expression of P2X1a does not modify the channel's current properties.

Alternative Splicing↗

PubMed2000

Molecular dynamics generation of nonarbitrary membrane models reveals lipid orientational correlations.

This report addresses the following problems associated with the generation of computer models of phospholipid bilayer membranes using molecular dynamics simulations: arbitrary initial structures and short equilibration periods, an Ewald-induced strong coupling of phospholipids, uncertainty regarding which value should be used for surface tension to alleviate the problem of the small size of the membrane, and simultaneous realization of both order parameters and the surface area. We generated a computer model of the liquid-crystalline L-alpha-dimyristoylphosphatidylcholine (DMPC) bilayer, starting from a configuration based on a crystal structure (rather than from an arbitrary structure). To break the crystalline structure, a 20-ps high-temperature pulse of 510 K (but not 450 or 480 K) was effective. The system finally obtained is an all-atom model, with Ewald summation to evaluate Coulombic interactions and a constant surface tension of 35 dynes/cm/water-membrane interface, equilibrated for 12 ns (over 50 ns total calculation time), which reproduces all of the experimentally observed parameters examined in this work. Furthermore, this model shows the presence of significant orientational correlations between neighboring alkyl chains and between shoulder vectors (which show the orientations of the lipids about their long axes) of neighboring DMPCs.

Computer Simulation↗

PubMed2000

Cholesterol effects on the phosphatidylcholine bilayer polar region: a molecular simulation study.

A molecular dynamics (MD) simulation of a fully hydrated, liquid-crystalline dimyristoylphosphatidylcholine (DMPC)-Chol bilayer membrane containing approximately 22 mol% Chol was carried out for 4.3 ns. The bilayer reached thermal equilibrium after 2.3 ns of MD simulation. A 2.0-ns trajectory generated during 2.3-4.3 ns of MD simulation was used for analyses to determine the effects of Chol on the membrane/water interfacial region. In this region, 70% of Chol molecules are linked to DMPC molecules via short-distance interactions, where the Chol hydroxyl group (OH-Chol) is 1) charge paired to methyl groups of the DMPC choline moiety ( approximately 34%), via the hydroxyl oxygen atom (Och); 2) water bridged to carbonyl ( approximately 19%) and nonester phosphate ( approximately 14%) oxygen atoms, via both Och and the hydroxyl hydrogen atom (Hch); and 3) directly hydrogen (H) bonded to carbonyl ( approximately 11%) and nonester phosphate ( approximately 5%) oxygen atoms, via Hch ( approximately 17% of DMPC-Chol links are multiple). DMPC's gamma-chain carbonyl oxygen atom is involved in 44% of water bridges and 51% of direct H bonds formed between DMPC and Chol. On average, a Chol molecule forms 0.9 links with DMPC molecules, while a DMPC molecule forms 2.2 and 0.3 links with DMPC and Chol molecules, respectively. OH-Chol makes hydrogen bonds with 1.1 water molecules, preferentially via Hch. The average number of water molecules H bonded to the DMPC headgroup is increased by 7% in the presence of Chol. These results indicate that inclusion of Chol decreases interlipid links and increases hydration in the polar region of the membrane.

Cholesterol↗

PubMed2000

Evaluation of the poly(ADP-ribose) polymerase gene in human stroke.

Nitric oxide (NO) and its reactant product, peroxynitrite, have been implied to mediate neuronal damage following cerebral ischemia. However, the cellular targets of these compounds remain unclear. Studies using poly(ADP-ribose) polymerase (PARP) inhibitors and PARP knock-out mice have recently demonstrated that excessive activation of this nuclear enzyme plays an important role in NO-induced neurotoxicity. To evaluate the relevance of this plausible candidate gene to human stroke, we undertook a case-control study in Japanese. Participants comprised 213 cerebral infarction cases and 374 age- and sex-matched controls. As a primary investigation, we screened polymorphic sites of the PARP gene, and newly identified a total of four polymorphisms in 1230-bp 5'-flanking sequence. None of them were, however, located on the known promoter components of the gene. Two bi-allelic polymorphisms selected and a CA-repeat polymorphism were subsequently characterized in the case-control study, but none were significantly associated with cerebral infarction in the present study. Our data thus suggest that the tested PARP polymorphisms do not principally contribute to cerebral infarction, although extensive searches would be required to clarify whether the PARP gene plays an important role in the pathogenesis of human stroke.

Adult↗

PubMed2000

Topical dinitrochlorobenzene therapy in the treatment of refractory atopic dermatitis: systemic immunotherapy.

BACKGROUND: Repeated dinitrochlorobenzene (DNCB) application has been proposed as a systemic immunotherapy on the basis of its ability to stimulate T helper 1 (T(H)1) responses, such as those for systemic lupus erythematosus and HIV infection. OBJECTIVE: We report the effect of topical DNCB therapy in an open trial in patients with refractory atopic dermatitis (AD). METHODS: Eight patients with refractory AD received weekly application of 0.2% to 1% DNCB to a 2. 5-cm(2) area on the upper arm after sensitization with 5% DNCB; the position was rotated at each application. Disease activity was monitored by pruritus score, percentage of body involvement, clinical severity score, eosinophil counts, serum IgE levels, and serum soluble interleukin 2 receptor levels. RESULTS: Six of 8 patients (patients 1-6) showed apparent improvement both on clinical scores and laboratory data until 16 weeks after DNCB therapy (week 16). The clinical severity scores of patients 1 to 6 were significantly correlated with eosinophil counts, IgE levels, and serum soluble interleukin 2 receptor levels. One patient did not show clear improvement, and another (patient 8) showed deterioration. DNCB therapy was discontinued at week 12 for patient 8. CONCLUSION: Topical DNCB may systemically stimulate T(H)1 cell responses of patients with AD, resulting in restoration of the T(H)1/T(H)2 imbalance and possible clinical improvement. These results, however, should be interpreted with caution until additional documentation is obtained.

Administration, Topical↗

PubMed2000

Invasive verrucous carcinoma: a temporal bone histopathology report.

Only nine cases of primary verrucous carcinoma of the temporal bone have been reported in the English literature. We describe histopathologic findings in a 78-year-old man dying of intracranial complications of primary verrucous carcinoma of the external auditory canal. Following autopsy the temporal bone was prepared for light microscopic examination. The temporal bone was serially sectioned horizontally after fixation, decalcification, and embedding, and each 10th section was stained with hematoxylin and eosin and examined by light microscopy. The carcinoma originated from the external auditory canal, infiltrating the mastoid cavity, the middle ear, tissue adjacent to the internal carotid artery, and the posterior cranial fossa, where it invaded the right cerebellum and produced an abscess. The labyrinth and internal auditory canal were not infiltrated. Metastasis to lymph nodes or distant sites was not identified. In the present case, the verrucous carcinoma originating from the external auditory canal extended into the posterior cranial fossa, while it did not invade the membranous labyrinth.

Aged↗

PubMed2000

Leukocytoclasis: ultrastructural in situ nick end labeling study in anaphylactoid purpura.

In order to characterize leukocytoclasis of polymorphonuclear neutrophils (PMNs), the method of in situ nick end labeling for DNA breakdown was applied on tissue samples from 36 patients with anaphylactoid purpura at ultrastructural, as well as light microscopic, level. Light microscopic immuno-peroxidase technique showed positively labeled PMNs infiltrating in the dermis of 24 cases in which leukocytoclastic vasculitis was fully developed, suggesting that breakdown of DNA strands is triggered in the PMNs. Electron microscopic immuno-gold technique employed in six patients with the fully developed stage of inflammation identified the DNA breaks in the nuclei of PMNs. Ultrastructure of these cells, however, showed that only a minor population ( approximately 1/60) of PMNs showed the condensed and marginated nuclei, being compatible with typical apoptotic change. However, the majority of immuno-gold-labeled cells showed relatively intact nuclei without margination of condensed heterochromatin and with disintegrated cytoplasmic organelles and plasma membrane, suggesting that apoptotic cell removal mechanism may be incomplete. The immuno-gold-positive nuclear debris scattering in the tissue is most likely the remnants of unsatisfactory disposal by apoptosis of potentially injurious PMNs, resulting in the vascular and perivascular damage in leukocytoclastic vasculitis in anaphylactoid purpura.

Adolescent↗

PubMed2000

Single molecule analysis of the actomyosin motor.

Progress in imaging techniques and nano-manipulation of single molecules has been remarkable. These techniques have allowed the accurate determination of myosin-head-induced displacements and of how the mechanical cycles of the actomyosin motor are coupled to ATP hydrolysis. This has been achieved by measuring mechanical and chemical events of actomyosin directly at the single molecule level. Recent studies have made detailed measurements of myosin step size and mechanochemical coupling. The results of these studies suggest a new model for the mechanism of motion underlying actomyosin motors, which differs from the currently accepted lever-arm swinging model.

Actomyosin↗

PubMed2000

The spike of S phase cyclin Cig2 expression at the G1-S border in fission yeast requires both APC and SCF ubiquitin ligases.

We describe a novel set of oscillation mechanisms for the fission yeast S phase cyclin Cig2, which contains an authentic destruction box and is destroyed at anaphase via the APC/cyclosome (APC/C). Unlike the mitotic cyclin Cdc13, however, Cig2 mRNA and protein peak at the G1/S boundary and decline to low levels in G2 and M phases. We show here that SCF(Pop1, Pop2) plays a role in transcriptional periodicity, as pop mutations result in constitutive cig2(+) transcripts. The instability of Cig2 during G2 and M is independent of either the APC/C or Pop1/Pop2, but requires Skp1, a core component of SCF. These data indicate that the APC/C and SCF control Cig2 levels differentially at different stages of the cell cycle.

Anaphase↗

PubMed2000

Cross-sectional study on risk factors of HIV among female commercial sex workers in Cambodia.

To describe epidemiological features on HIV prevalence among female commercial sex workers (CSWs), a cross-sectional study on sexual behaviour and serological prevalence was carried out in Cambodia. The CSWs were interviewed on their demographic characters and behaviour and their blood samples were taken for testing on sexually transmitted diseases, including HIV, Chlamydia trachomatis, syphilis, and hepatitis B. Associations between risk factors and HIV seropositivity were analysed. High seroprevalence of HIV and Chlamydia trachomatis IgG antibody (CT-IgG-Ab) was shown among the CSWs (54 and 81.7%, respectively). Univariate logistic regression analyses showed an association between HIV seropositivity and age, duration of prostitution, the number of clients per day and CT-IgG-Ab. Especially, high-titre chlamydial seropositivity showed a strong significant association with HIV prevalence. In multiple logistic regression analyses, CT-IgG-Ab with higher titre was significantly independently related to HIV infection. These suggest that existence of Chlamydia trachomatis is highly related to HIV prevalence.

Adolescent↗

PubMed2000

Prognostic value of p53 gene mutations and the product expression in de novo acute myeloid leukemia.

In acute myeloid leukemia (AML), p53 mutations are reportedly infrequent but associated with a poor prognosis. The majority of mutations are missense mutations, which generally lead to accumulation of nuclear p53 protein. However, the prognostic significance of the accumulation remains unknown in AML. In this study, we compared the prognostic value of p53 mutations versus accumulation of the product. p53 mutations were found in 9 (4.5%) of 200 patients with de novo AML. The p53 mutation detectable (mutation+) group had a worse prognosis (p = 0.0009) than the mutation not detectable (mutation-) group. Multivariate analysis showed that the p53 mutation was an independent factor (p = 0.005) for short overall survival as well as 60 yr or older (p = 0.001) and unfavorable karyotypes (p = 0.001). In 79 of the 200 patients, the expression of p53 was studied by immunocytochemistry (ICC) using anti-p53 monoclonal antibody (DO-7). All samples carrying missense mutations (N = 6) were positive for ICC in over 15% of nuclei of each sample, chosen as the optimized cutoff value of p53 accumulation. Accumulation was thus found in 14 of the 79 patients. However, there was no prognostic difference according to the accumulation, because the mutation-/accumulation+ group (N = 8) tended to have a good prognosis. These findings indicate that molecular detection of p53 mutations yields better prognostic information than ICC. In a subset of AML, p53 protein might be accumulated without mutation presumably due to upstream signals of p53.

Acute Disease↗

PubMed2000

Involvement of CD95-independent caspase 8 activation in arsenic trioxide-induced apoptosis.

Arsenic trioxide (As2O3)-treatment is effective in acute promyelocytic leukemia (APL) patients with t(15;17). Clinically achievable concentrations of As2O3 induce apoptosis in NB4, an APL cell line, in vitro. Here, to study the mechanism of As2O3-induced apoptosis, we established an As2O3-resistant subline, NB4/As. Growth of NB4/As was inhibited by 50% after 2 day-treatment (IC50) at 1.6 microM As2O3, whereas IC50 of NB4 was 0.3 microM. Degradation of PML-RARalpha and change of the PML-subcellular localization were similarly induced by As2O3 in NB4 and NB4/As, suggesting that their contribution to apoptosis is small. Treatment with 1 microM As2O3 induced the activation of caspase 3 as well as a loss of mitochondrial transmembrane potential (deltapsim) in NB4 but not in NB4/As. Caspase 8 and Bid were also activated by As2O3 in NB4 but not in NB4/As. In NB4, an inhibitor of caspase 8 blocked not only the activation of caspase 3 but also the loss of deltapsim. Neither cell line expressed CD95/Fas, and agonistic anti-Fas antibody (CH-11) failed to cause apoptosis. Neither antagonistic anti-CD95/Fas antibody nor anti-Fas ligand antibodies influenced the As2O3-induced apoptosis. NB4/As had a higher concentration of intracellular glutathione (GSH) than NB4 (96 vs 32 nmol/mg). Reduction of the GSH level by buthionine sulfoxide (BSO) completely restored the sensitivity to As2O3 in NB4/As. Furthermore, caspase activation and the loss of deltapsim were recovered by combination treatment with BSO. These findings suggest that the As2O3 treatment activates caspase 8 in a CD95-independent but GSH concentration-dependent manner. In combination with BSO, As2O3 might be applied to therapy of leukemia/cancers which are insensitive to the clinically achievable concentrations of As2O3.

Antineoplastic Agents↗

PubMed2000

Role of P-glycoprotein in all-trans retinoic acid (ATRA) resistance in acute promyelocytic leukaemia cells: analysis of intracellular concentration of ATRA.

We analysed the relationship between all-trans retinoic acid (ATRA) resistance and P-glycoprotein (P-gp)-associated multidrug resistance (MDR) in acute promyelocytic leukaemia (APL). There was no difference in the intracellular ATRA accumulation between NB4 cells and an MDR1 cDNA-transduced NB4 subline and between ATRA-resistant NB4 cells (NB4/RA) and an MDR1 cDNA-transduced NB4/RA subline. PSC833, a MDR modifier, did not increase the intracellular accumulation of ATRA or affect the expression of CD11b, the nitroblue tetrazolium (NBT) reduction activity, the proportion of apoptotic cells or the morphology of these four ATRA-treated cell lines. Similar results were obtained in the analysis of APL cells from five patients relapsed after ATRA-induced complete remission.

ATP Binding Cassette Transporter, Subfamily B, Mem↗