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Biomedical subjects

T Koga

Publications and source records attributed to T Koga.

At least 91 records · Page 5Linked to original sources
PubMed2000

Rib metastasis appearing 8 years after surgery for lung cancer: report of a case.

A 39-year-old man underwent a right upper lobectomy and lymph node dissection for right lung adenocarcinoma on March 7, 1988. He was referred for an evaluation of a systemic bone scintillation scan on October 29, 1996. A hot spot at the right fourth rib was recognized. After performing needle aspiration cytology, a diagnosis of adenocarcinoma was made. This case was considered to be rib metastasis occurring 8 years after surgery for lung cancer. In general, regular follow-up examinations are performed for at least 5 years after surgery; however, surgeons should also keep such late metastatic cases in mind.

Adenocarcinoma↗
PubMed2000

Cytokines and chemokines in the epidermis.

Keratinocytes (KC) produce a vast repertoire of cytokines, including interleukins, growth factors, colony stimulating factors, and chemokines. Under normal conditions, most of them are not synthesized or remain in the cytoplasm, but external stimuli, such as trauma, bacterial infections, chemical substances, or ultraviolet irradiation induce the production and release of these cytokines from KC. KC-derived cytokines regulate the immune and inflammatory responses through their receptors on KC, Langerhans cells, dermal fibroblasts and endothelial cells, and infiltrating T-cells.

Animals↗
PubMed2000

Simple and rapid detection of Streptococcus mutans and Streptococcus sobrinus in human saliva by polymerase chain reaction.

Streptococcus mutans and Streptococcus sobrinus are major pathogens causing dental caries in humans. A simple and rapid method to detect these species in human saliva simultaneously was developed using the polymerase chain reaction (PCR). Chromosomal DNA was extracted by boiling bacterial cells in lysis solution containing 1% Triton X-100. Oligonucleotide primers specific for portions of the glucosyltransferase genes (gtfB of S. mutans and gtfI of S. sobrinus) were designed. After PCR using two sets of these primers, S. mutans and S. sobrinus were specifically identified. The method was capable of amplifying DNA fragments specific for these species from chromosomal DNA extracted from 1 x 10(3) cells, or from 10 microliters of clinical saliva samples containing 1 x 10(3) colony-forming units of either streptococcal species. A second PCR, using the first PCR product as a template with newly designed internal primers, made it possible to detect 1 x 10(2) colony-forming units of either streptococcal species in 10 microliters of saliva samples. These results indicate that the PCR method developed in this study is useful for detecting S. mutans and S. sobrinus in saliva and that it can be used in epidemiological studies to evaluate the prevalence level of these organisms.

Adult↗
PubMed2000

CD1a+, CD3+, CD4+, CD8+, CD68+ and cutaneous lymphocyte-associated antigen-positive cells in Bowen's disease.

BACKGROUND: Bowen's disease (BD) is a squamous cell carcinoma in situ that rarely invades into the underlying dermis. However, little is known about its immunohistology. Objectives To evaluate the relationship between the cytological properties of the tumour cells in BD and the host immune response. METHODS: We examined the expression of p53, proliferating cell nuclear antigen (PCNA) and Ki67 antigen, and the number of mitotic cells, together with the number of intratumoral and dermal infiltrating CD1a+, CD3+, CD4+, CD8+, CD68+ and cutaneous lymphocyte-associated antigen (CLA)+ cells in 18 cases of genital BD. RESULTS: When compared with normal genital skin (n = 10), there was a significantly higher number of mitotic cells as well as higher expression of p53+, PCNA+ and Ki67+ cells in BD. There was significant mutual correlation between CD3+, CD4+ and CD68+ cells in the tumoral epidermis. The number of CD1a+ Langerhans cells significantly decreased in BD epidermis; however, dermal CD1a+ cells were increased. Interestingly, numbers of dermal CD1a+ cells significantly correlated with those of intratumoral CD3+, CD4+ and CD68+ cells. In situ hybridization for human papillomavirus (HPV) demonstrated that HPV-infected BD had significantly less infiltration of intratumoral CD3+ cells and CLA+ cells. CONCLUSIONS: The present data suggest that dermal CD1a+ cells may participate in the immune surveillance and that HPV infection may interfere with the intratumoral infiltration of CLA+ cells in BD.

Antibody Formation↗
PubMed2000

Postoperative outcome and sites of recurrence in patients following curative resection of gastric cancer.

BACKGROUND: Recurrence occurs in a variety of forms and in different organs after 'curative resection' of gastric cancer. This study investigated the postoperative prognosis for each type of recurrence. METHODS: From 1969 to 1988, 939 patients with gastric cancer underwent curative resection; data on 130 of 207 patients who died with recurrence were analysed. Attention was focused on the site of recurrence and the postoperative outcome. RESULTS: Haematogenous recurrence was evident in 54 per cent (70 of 130 patients), peritoneal recurrence in 43 per cent (56 of 130), lymph node recurrence in 12 per cent (16 of 130) and local recurrence in 22 per cent (29 of 130). Thirty-three patients (25 per cent) had recurrences at multiple sites. Peritoneal and local recurrences were related to infiltrative growth, in contrast to haematogenous and lymphatic recurrences. There were no statistical differences in survival time among each type of recurrence and survival was not related to the number of sites of recurrence. Survival did not depend on factors of sex, age, tumour location, tumour size, depth of invasion, tissue differentiation, histological growth pattern, lymphatic and vascular involvement, lymph node metastasis and extent of lymph node dissection. CONCLUSION: The clinicopathological characteristics of gastric cancer determine the type of recurrence, although the clinical outcome is the same for each type of tumour and is not related to the number of sites of recurrence.

Humans↗
PubMed2000

CD14-dependent and independent pathways in lipopolysaccharide-induced activation of a murine B-cell line, CH12. LX.

Using a lipopolysaccharide (LPS)-responsive murine B-cell line, CH12. LX, we assessed the possible role of CD14 in LPS-induced activation of B cells. Flow cytometric analysis indicated that CH12.LX cells expressed the CD14 molecule with a lower intensity than did the macrophage cell line J774.1. A reverse transcription-polymerase chain reaction and Northern blot analysis revealed low, but significant, levels of CD14 mRNA in CH12.LX cells, whose cDNA was identical to that of the mouse macrophage CD14 gene. After stimulation with LPS, CH12.LX cells proliferated, accompanied by up-regulations of CD14, transforming growth factor (TGF)-beta and interleukin (IL)-6 mRNA, and increased IgM and IgA secretion. In the absence of serum or with the addition of anti-CD14 monoclonal antibodies, however, LPS-stimulation induced neither the up-regulation of CD14 and TGF-beta mRNA nor an increase in IgA secretion. These findings indicate that CD14 expression is not restricted to myeloid cells, but is involved in some cellular activation events of murine B cells elicited by LPS. Furthermore, a CD14-independent pathway may also exist in the LPS-induced activation of B cells that leads to proliferation, IL-6 production and the enhancement of IgM (but not IgA) secretion.

Animals↗
PubMed2000

The Koga Hospital Center for studies on sleep: status report.

Between September 1996 and January 1999 we used polysomnography (PSG) to examine 473 patients (involving a total of 662 records). The diagnosis was a sleep-related breathing disorder in 256 patients, including sleep apnea syndrome (SAS) in 194 patients, sleep hypoxicemia in 18 and insomnia in the other four. The SAS consisted of three subtypes: central apnea (CA) in 56 patients, obstructive apnea (OA) in 124 and mixed apnea (MA) in eight. The ratio of central apnea was relatively higher than the national average. Among the 473 patients, the most common complication was heart disease (133 patients) while other complications included hypertension, and respiratory and cerebrovascular diseases. Concerning the therapy for these patients, continuous positive airway pressure therapy was the most commonly applied and was effective in each type of SAS (CA, OA, MA). Other therapies included prosthetic mandibular advancement, bilevel positive airway pressure, medication and ENT operations. In Koga Hospital, there are many patients with heart disease and/or respiratory disease. We examined those patients who presented with snoring and/or apnea using PSG. Among these patients, SAS was the most common sleep disorder. The relative ratio of CA was high and the average age was higher than those with OA.

Adult↗
PubMed2000

Vascular invasion and potential for tumor angiogenesis and metastasis in gastric carcinoma.

BACKGROUND: Hematogenous metastasis occurs when cancer cells released from the primary site enter blood vessels and are transported to distant organs, where they attach and proliferate. Angiogenesis is essential for tumor growth and metastasis and depends on the production of angiogenic factors by tumor cells. METHODS: We analyzed data on 1184 Japanese adult men and women with gastric cancer with respect to the relation between vascular invasion and the potential for tumor angiogenesis and metastasis. All these patients were treated from 1976 to 1995 in the Department of Surgery II, Kyushu University. In 300 patients, the expression of vascular endothelial growth factor (VEGF) and p53 protein in tumor tissues was examined by using an immunohistochemical staining method or Northern blotting or both. Intratumoral microvessels were stained with anti-CD31 monoclonal antibody. RESULTS: Vascular invasion was evident in 254 patients (21.5%), and in these patients lymphatic invasion was more frequent and the rate of lymph node metastasis was higher in relation to the extent of vascular invasion. The positive findings were directly related to the depth of invasion and the presence of lymph node and liver metastasis. Tumor invasive and metastatic rates increased in relation to the extent of vascular invasion. Expressions of VEGF and p53 protein were higher and microvessel density was more prominent in tumor tissues in relation to the extent of vascular invasion. A close relation between VEGF and p53 protein expressions was also noted in tumors that showed vascular invasion. The expression of VEGF is one of the independent risk factors for vascular invasion. The postoperative outcome was poorer in patients with vascular invasion in relation to the extent of vascular invasion. CONCLUSIONS: Our findings show that gastric cancers with characteristics of vascular invasion have greater intratumoral angiogenesis and that VEGF and p53 overexpression is associated with intratumoral angiogenesis and metastases to distant organs.

Adult↗
PubMed2000

Characterization of a novel Vibrio parahaemolyticus phage, KVP241, and its relatives frequently isolated from seawater.

A vibriophage, KVP241, and six of its relatives were isolated independently from seawater using Vibrio parahaemolyticus as the host. All of the phages had the same morphology (a hexagonal head and a tail with a contractile sheath) and the same host range (specific for some V. parahaemolyticus strains). DNA-DNA hybridization experiments elucidated that their genomes are highly homologous to each other. Analyses of amino acid sequences of putative major capsid proteins indicated that KVP241 may be weakly related to T4-type phages having a more elongated head.

Amino Acid Sequence↗
PubMed2000

Formation of methyl mercaptan from L-methionine by Porphyromonas gingivalis.

Methyl mercaptan production by oral bacteria is thought to be one of the main causes of oral malodor. We examined the ability of periodontopathic Porphyromonas gingivalis to produce methyl mercaptan from L-methionine and found that the invasive strains W83 and W50 produced large amounts of methyl mercaptan. We cloned and sequenced the mgl gene encoding L-methionine-alpha-deamino-gamma-mercaptomethane-lyase (METase) from P. gingivalis W83. The structural mgl gene consisted of 1,200 bp and encoded a 43.3-kDa protein. To examine the role of methyl mercaptan in the pathogenesis of P. gingivalis, a METase-deficient mutant of P. gingivalis W83 was constructed. The methionine degradation activity and virulence of the mutant (M1217) and the parent strain (W83) in mice were compared. M1217 showed a marked decrease in the formation of methyl mercaptan from L-methionine and decreased virulence compared with the wild-type strain W83. These results suggest that methyl mercaptan not only is one of the sources of oral malodor, but may also play a role in the pathogenicity of P. gingivalis.

Animals↗
PubMed2000

Role of serotype-specific polysaccharide in the resistance of Streptococcus mutans to phagocytosis by human polymorphonuclear leukocytes.

To clarify the role of cell surface components of Streptococcus mutans in resistance to phagocytosis by human polymorphonuclear leukocytes (PMNs), several isogenic mutants of S. mutans defective in cell surface components were studied with a luminol-enhanced chemiluminescence (CL) assay, a killing assay, and a transmission electron microscope. The CL responses of human PMNs to mutant Xc11 defective in a major cell surface antigen, PAc, and mutant Xc16 defective in two surface glucosyltransferases (GTF-I and GTF-SI) were the same as the response to the wild-type strain, Xc. In contrast, mutant Xc24R, which was defective in serotype c-specific polysaccharide, induced a markedly higher CL response than the other strains. The killing assay showed that human PMNs killed more Xc24R than the parent strain and the other mutants. The transmission electron microscopic observation indicated that Xc24R cells were more internalized by human PMNs than the parental strain Xc. These results may be reflected by the fact that strain Xc24R was more phagocytosed than strain Xc. The CL response of human PMNs to a mutant defective in polysaccharide serotype e or f was similar to the response to Xc24R. Furthermore, mutants defective in serotype-specific polysaccharide were markedly more hydrophobic than the wild-type strains and the other mutants, suggesting that the hydrophilic nature of polysaccharides may protect the bacterium from phagocytosis. We conclude that the serotype-specific polysaccharide, but not the cell surface proteins on the cell surface of S. mutans, may play an important role in the resistance to phagocytosis.

Antigens, Bacterial↗
PubMed2000

Biophysical properties and responses to neurotransmitters of petrosal and geniculate ganglion neurons innervating the tongue.

The properties of afferent sensory neurons supplying taste receptors on the tongue were examined in vitro. Neurons in the geniculate (GG) and petrosal ganglia (PG) supplying the tongue were fluorescently labeled, acutely dissociated, and then analyzed using patch-clamp recording. Measurement of the dissociated neurons revealed that PG neurons were significantly larger than GG neurons. The active and passive membrane properties of these ganglion neurons were examined and compared with each other. There were significant differences between the properties of neurons in the PG and GG ganglia. The mean membrane time constant, spike threshold, action potential half-width, and action potential decay time of GG neurons was significantly less than those of PG neurons. Neurons in the PG had action potentials that had a fast rise and fall time (sharp action potentials) as well as action potentials with a deflection or hump on the falling phase (humped action potentials), whereas action potentials of GG neurons were all sharp. There were also significant differences in the response of PG and GG neurons to the application of acetylcholine (ACh), serotonin (5HT), substance P (SP), and GABA. Whereas PG neurons responded to ACh, 5HT, SP, and GABA, GG neurons only responded to SP and GABA. In addition, the properties of GG neurons were more homogeneous than those of the PG because all the GG neurons had sharp spikes and when responses to neurotransmitters occurred, either all or most of the neurons responded. These differences between neurons of the GG and PG may relate to the type of receptor innervated. PG ganglion neurons innervate a number of receptor types on the posterior tongue and have more heterogeneous properties, while GG neurons predominantly innervate taste buds and have more homogeneous properties.

Acetylcholine↗
PubMed2000

A single amino acid deletion in the carboxy terminal of apolipoprotein A-I impairs lipid binding and cellular interaction.

The carboxy-terminal region of apolipoprotein (apo) A-I has been shown by mutagenesis or synthetic peptides to play an important role in lipid binding. However, the precise functional domain of the C-terminal remains to be defined. In this study, apoA-I Nichinan, a naturally occurring human apoA-I variant with a deletion of glutamic acid 235, was expressed in Escherichia coli to examine the effect of this mutation on the functional domain of apoA-I for lipid binding and related consequences. A dimyristoyl phosphatidylcholine binding study with recombinant (r-) proapoA-I Nichinan showed a significantly slow initial rate of lipid binding. On preincubation with human plasma lipoprotein fractions (d<1.225 g/mL) at 37 degrees C for 1 hour, (125)I-labeled normal r-proapoA-I was chromatographed as a single peak at the high density lipoprotein (HDL) fraction, whereas (125)I-labeled r-proapoA-I Nichinan was chromatographed into the HDL fraction as well as the free r-proapoA-I fraction (23% of radioactivity). Circular dichroism measurements showed that the alpha-helix content of lipid-bound r-proapoA-I Nichinan was reduced, being 62% (versus 73%) of normal r-proapoA-I. Nondenaturing gradient gel electrophoresis of reconstituted HDL particles assembled with r-proapoA-I Nichinan and normal r-proapoA-I showed similar particle size. To study cholesterol efflux, human skin fibroblasts were labeled with [(3)H]cholesterol, followed by incubation with either lipid-free r-proapoA-I or DMPC/r-proapoA-I complex. Fractional cholesterol efflux from [(3)H]cholesterol-labeled fibroblasts to lipid-free r-proapoA-I Nichinan or DMPC/r-proapoA-I Nichinan complexes was significantly reduced relative to that of normal r-proapoA-I or DMPC/r-proapoA-I during the 6-hour incubation. Binding assays of human skin fibroblasts by lipid-free r-proapoA-I showed that r-proapoA-I Nichinan was 32% less bound to fibroblasts than was normal r-proapoA-I. Our data demonstrate that the deletion of glutamic acid 235 at the C-terminus substantially reduces the lipid-binding properties of r-proapoA-I Nichinan, which may cause a reduction in its capacity to interact with plasma membranes as well as to promote cholesterol efflux from cultured fibroblasts.

Apolipoprotein A-I↗
PubMed2000

Neurally mediated syncope induced by lung cancer--a case report.

The authors present hemodynamic and autonomic features of recurrent and episodic neurally mediated syncope in a man with lung cancer involving afferent vagus. He revealed extreme hypotension with bradycardia occurring during sitting or standing. A head-up tilt test also induced syncope. However, syncope attacks no longer occurred 2 weeks after admission. Alternatively, the paralyses of the left recurrent laryngeal nerve and the left phrenic nerve developed. It is suggested that the lung cancer involved upper rootlets of the left vagus and caused transient hypersensitivity of baroreceptor function that resulted in neurally mediated syncope.

Carcinoma, Large Cell↗
PubMed2000

Adult reversible cardiomyopathy with pituitary adrenal insufficiency caused by empty sella--a case report.

The authors report a first case of reversible cardiomyopathy in an adult with adrenal insufficiency. A 62-year-old man was administered to hospital because of congestive heart failure. The electrocardiogram showed prolonged QT interval and negative T wave on the right precordial leads and frequent multifocal ventricular premature contractions. On the echocardiogram, the left ventricle was revealed to be diffusely hypokinetic with remarkable enlargement. 201Thallium single photon emission computed tomography (SPECT) revealed multiple flow defects in the left ventricular wall. He also had pituitary adrenal insufficiency secondary to an empty sella, which was diagnosed by hormonal studies and magnetic resonance images of the brain. After the replacement therapy with hydrocortisone, heart failure was sufficiently resolved. Abnormal flow defects in the myocardium on SPECT were also improved. To the authors' knowledge, adrenal insufficiency with cardiomyopathy has not been previously described in adult patients.

Adrenal Insufficiency↗