Biomedical subjects

R Yamaguchi

Publications and source records attributed to R Yamaguchi.

At least 91 records · Page 5Linked to original sources

PubMed1997

A mutant metallothionein which has inverse fragment composition exhibits high cadmium-binding ability.

In order to investigate the role of the alpha-fragment of metallothionein (MT) in metal-binding, two mutant MTs, beta Ala alpha Cys- and alpha Cys beta Cys-mutant MTs, expressed in Escherichia coli were analyzed for their metal-binding ability. A mutant MT where all of the cysteine residues in the beta-fragment of MT were substituted by alanine residues and another mutant MT that had the inverse fragment composition (alpha-beta, i.e., beta-alpha in wild-type MT) were designated as the beta Ala alpha Cys and the alpha Cys beta Cys-mutant MT's, respectively. Both expressed Cd-binding mutant MTs were identified by amino acid analyses. From their metal-binding capacities, the two mutant MTs exhibited higher Cd-binding abilities than wild-type MT. The results suggested that the alpha-fragment plays a key role in the Cd-binding of MT, and that the metal-binding tightness of MT is dependent on the metal-binding ability of a prior fragment in MT.

Alanine↗

PubMed1997

Cigarette smoking induces an increase in oxidative DNA damage, 8-hydroxydeoxyguanosine, in a central site of the human lung.

To evaluate the effect of cigarette smoking on oxidative stress in lung tissues, we compared the levels of a type of oxidative DNA damage, 8-hydroxydeoxyguanosine (8-OH-dG), in tissue obtained from the central sites of lungs from 14 current smokers, seven ex-smokers and nine non-smokers. The mean level of 8-OH-dG in the lung tissues from smokers was 1.43-fold higher than that of the non-smokers (the difference was statistically significant, P = 0.0262). A positive correlation between the 8-OH-dG levels in normal lung tissues and the Brinkman index was obtained from smokers and ex-smokers (r = 0.525; P = 0.0134). A positive correlation was also obtained for the 8-OH-dG levels in normal lung tissues and the number of cigarettes smoked per day (r = 0.436; P = 0.0132). These results suggest that oxidative DNA damage is induced in lung DNA by cigarette smoking.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed1997

Significance of alpha-fragment of metallothionein in cadmium binding.

In order to evaluate the significance of alpha- and beta-fragments of metallothionein with regard to Cd binding in biosynthetic processes, the Cd-binding ability of four mutant metallothioneins was examined using the Escherichia coli expression system. The features of the mutant metallothioneins were proteins in which cysteine residues in the alpha- or beta-fragment were replaced with alanine residues, or that the sequential order of the fragments was altered. The expressed mutant metallothioneins having an intact alpha-fragment showed the constructive abilities of the Cd-thiolate cluster. On the other hand, mutant metallothionein having an alpha-fragment lacking metal-binding sites exhibited no Cd-binding ability. The condition for maintaining the Cd-binding capability of metallothionein was that the alpha-fragment remains intact irrespective of the sequential order of the two fragments. The alpha-fragment is an indispensable component in metal-binding processes of Cd-metallothionein.

Amino Acid Sequence↗

PubMed1997

Malignant aortic body tumor in a Holstein cow.

A malignant aortic body tumor was observed in a 5-year-old female Holstein cow. The neoplastic mass, of 22 x 17 x 15 cm in size, was located at the base of the left atrium, having irregular lobular structures. The tumor cells had slightly eosinophilic cytoplasm, and a round or oval nucleus. Metastasis was only present in the premediastinal lymph node. The tumor cells exhibited intense immunoreactivity for neuron-specific enolase (NSE) and synaptophysin, and were moderately positive for chromogranin A. Electronmicroscopy revealed membrane-limited granules in the cytoplasm. The cultured cells were spindle in shape, and having projectional cytoplasm. They were intensely positive for NSE, synaptophysin, chromogranin A, and neurofilament (200 kD). Consequently, this case was diagnosed as a malignant aortic body tumor from the neuroecrodermal origin.

Animals↗

PubMed1997

alpha-Fetoprotein-producing rectal carcinoma--a case report.

A case with an alpha-fetoprotein (AFP)-producing carcinoma originating from the rectum is described. A 71-year-old male patient, who underwent a rectectomy for rectal carcinoma, developed space occupying lesions in the liver and a remarkable AFP elevation (220,000 ng/ml) in the 6th month postoperatively, and then expired one year later. Histologically, the rectal carcinoma consisted of well-differentiated adenocarcinomas, and contiguous cancerous cells proliferating in either a medullary or trabecular pattern. In the "trabecular" areas, localization of AFP was confirmed immunohistochemically. Results of concanavalin A or lens culinaris agglutinin affinity chromatography demonstrated that it was between a hepatic type and a yolk sac type, and was considered to be an intestinal type. This could have been an AFP-producing rectal carcinoma, in which the patient experienced liver metastasis at a relatively early postoperative period and died. This shows that AFP-producing rectal carcinomas are highly malignant, biologically, similar to AFP-producing gastric cancers.

Adenocarcinoma↗

PubMed1997

Effect of solution pH on the calcium phosphates formation and ionic diffusion on and through the collagenous matrix.

The effect of pH on the calcification and the permselectivity for the Ca2+ and PO4(3-) ions of a collagenous matrix were studied at pH6.5, 7.0 and 7.4 and at 37 degrees C, using slices of Achilles tendon of a cow, which were cut into disks, in an experimental system where Ca2+ and PO4(3-) ions diffused into the collagen disk from the mutually opposite sides of the disk. The products on and inside the disk were a mixture of octacalcium phosphate (OCP) and apatite regardless of the solution pH. At pH6.5, few crystals grew on the PO4-side of the disk, while many crystals grew on the Ca-side. Crystal growth on the PO4-side was enhanced at higher pH, while that on the Ca-side was suppressed. With an increase in pH, the diffusion of Ca2+ ion through the disk increased, while that of PO4(3-) ion decreased. The mode of crystal growth on the collagen disk was consistent with the mode of ionic diffusion through the matrix. Inside the disk, the influence of pH on the crystal growth was not obvious. It was suggested that the electrochemical property of the collagenous matrix regulated the ionic inflow into the matrix and thereby affected its calcification.

Achilles Tendon↗

PubMed1997

Multiple urinary cytokine levels of bacterial cystitis.

PURPOSE: We have examined urinary cytokine levels to define the inflammatory response in patients with bacterial cystitis or microhematuria relative to normal subjects. Cytokines examined include interleukin-1beta (IL-1beta), IL-1alpha, tumor necrosis factor (TNF alpha), IL-6 and IL-4. Unique features of this study include a) a simultaneous study of several relevant cytokines b) a study of the inflammatory response at both low and high counts of bacterial infection and c) an assessment of whether microhematuria without bacterial cystitis or pyuria is associated with cytokine elevation compared to normals. MATERIALS AND METHODS: Enzyme immunoassays were utilized for each cytokine. Patients studied include those with bacterial cystitis (n = 49), patients with microhematuria (n = 11), and normal subjects (n = 36). Cytokine levels were also determined for patients with low count bacterial cystitis (1,000-50,000 organisms; n = 15) and compared to high count bacterial cystitis (>100,000 organisms; n = 34) and normal subjects. Statistical analysis was carried out using the Kruskal-Wallis test followed by pairwise testing with Newman-Keuls test. RESULTS: a) The means for normal, microhematuria and bacterial cystitis groups were significantly different (p <0.05) for IL-1beta, IL-1alpha, TNF alpha and IL-6, but not for IL-4. b) Except for IL-4, all cytokines were found to be significantly elevated in low count bacterial cystitis compared to normals. No statistically significant difference was observed between low and high count bacterial cystitis groups for any of the cytokines tested. CONCLUSIONS: a) Significant and similar inflammatory responses are present in both low and high count bacterial cystitis groups as compared with the normal group. b) IL-6 and TNF alpha are significantly elevated in patients with microhematuria compared to normals. c) The potential clinical utility of the assays lies in identifying the specific cytokines elevated, understanding the pathways that give rise to their production, and in defining potential virulence factors that may produce significant inflammation at low count bacterial infections.

Colony Count, Microbial↗

PubMed1997

Clinical, morphologic, and biochemical characteristics of Chediak-Higashi syndrome in fifty-six Japanese black cattle.

OBJECTIVE: To characterize Chediak-Higashi syndrome (C-HS) in Japanese Black cattle. ANIMALS: 56 of 200 cattle with a bleeding disorder and giant granules in leukocytes. PROCEDURE: Clinical observation, CBC, hemostatic screening test, platelet aggregometry, electron microscopy, platelet constituent analysis, and ophthalmoscopic examination were done. RESULTS: Affected Japanese Black cattle had increased bleeding tendency and abnormal granules in their leukocytes. Susceptibility to infection was not increased. Cutaneous albinism was evident in 6 new-born calves, but not in most affected cattle. In all affected cattle, the tapetal fundus was pale and the nontapetal fundus was almost devoid of pigment. By electron microscopy, a remarkable decrease in the number of dense granules in platelets was observed. Functionally, collagen-induced platelet aggregation was markedly reduced. CONCLUSIONS: This bleeding disorder was diagnosed as C-HS. With regard to susceptibility to infection, albinism, and mortality, clinical manifestations of C-HS in Japanese Black cattle were moderate, compared with C-HS in human beings and Hereford cattle. CLINICAL RELEVANCE: Because an autosomal recessive mode of inheritance was documented and recessive homozygotes could be easily detected, C-HS in Japanese Black cattle can be controlled.

Adenosine Diphosphate↗

PubMed1997

A new human hepatocellular carcinoma cell line (HAK-2) forms various structures in collagen gel matrices.

We established a new human hepatocellular carcinoma (HCC) cell line, designated HAK-2, from a surgically resected HCC of a 57-yr-old Japanese man. The patient's tumor consisted of 5 different histological features in a single nodule: well-differentiated HCC with trabecular pattern; and moderately differentiated HCC with 4 different patterns (i.e., trabecular, pseudoglandular, solid, and scirrhous). Morphologically, HAK-2 cells on a plastic dish showed oval-shaped nuclei and large flat, polygonal eosinophilic cytoplasm and proliferated in a monolayered sheet with a population doubling time of 36.8 hours. Meanwhile, various structures, such as compact, trabecular, and tubular arrangements, were induced in HAK-2 cells cultured in type I collagen gel matrix. Also, HAK-2 cells in vitro underwent spontaneous apoptosis more frequently than other HCC cell lines examined. HAK-2 cells secreted various plasma proteins including albumin into the culture medium. Chromosome and flow cytometric analyses revealed that HAK-2 had many structural abnormalities with human karyotype and a single aneuploid cell population with a DNA index of 3.7, respectively. These findings suggest that HAK-2 is a new human HCC cell line representing two morphological characteristics; (1) formation of various structures in the presence of extracellular matrix and (2) frequent spontaneous apoptosis in vitro.

Aneuploidy↗

PubMed1996

Paxillin association in vitro with integrin cytoplasmic domain peptides.

Short cytoplasmic domains of integrin heterodimers are crucial for transduction of signals generated by adhesion of cells to the extracellular matrix. Here, we describe the use of peptides mimicking the intracellular tails of integrin alpha5beta1 to assay in vitro associations with cytoskeletal proteins. Our results suggest that the focal adhesion protein, paxillin, may interact directly with the intracellular region of the integrin beta1 subunit. Paxillin is known to form stable complexes with several signaling molecules, including focal adhesion kinase. Physical interaction between paxillin and the beta1 cytoplasmic domain suggests a model in which paxillin may function as a key intermediary in integrin-mediated signal transduction.

Amino Acid Sequence↗

PubMed1996

Increase of a type of oxidative DNA damage, 8-hydroxyguanine, and its repair activity in human leukocytes by cigarette smoking.

To investigate the oxidative stress induced by cigarette smoking, the levels of a form of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), and its repair activity in the leukocytes of current smokers, ex-smokers, and complete nonsmokers were measured. The mean level of 8-OH-Gua was 1.88-fold higher in smokers as compared to complete nonsmokers (the difference was statistically significant, P = 0.013). The mean 8-OH-Gua repair activity was 1.6-fold higher in smokers than complete nonsmokers (the difference was statistically significant, P = 0.0053). A positive association was observed for the 8-OH-Gua levels and its repair activity. Considerable interindividual variations in the 8-OH-Gua levels (current smokers, 3.5-fold; nonsmokers, 7.2-fold) and in its repair activity (current smokers, 7.5-fold; nonsmokers. 5.5-fold) were observed. These results demonstrate that not only smoking status but also life-style, environment, and genetic differences might have effects on the level of 8-OH-Gua and its repair activity in human leukocytes.

Adult↗

PubMed1996

Lack of a kinetic interaction between fluconazole and mexiletine.

OBJECTIVE: To investigate the effect of fluconazole on the kinetics of mexiletine. METHODS: Six healthy male volunteers participated in a crossover study. On the 1st day, the subjects received 200 mg mexiletine alone. On days 2-7 they received 200 mg fluconazole orally, and on day 8 they received 200 mg mexiletine and 200 mg fluconazole concomitantly. In a third phase two subjects received 400 mg fluconazole daily. RESULTS: No differences in concentrations were observed between the three phases. The area under the concentration curves (AUC) after administration of mexiletine alone and in combination with fluconazole 200 mg/day were 6.63 and 7.31 micrograms.h.ml-1, respectively. CONCLUSION: These findings suggest that fluconazole does not inhibit mexiletine metabolism.

Adult↗

PubMed1996

Special considerations in endopyelotomy in a horseshoe kidney.

We report a patient with ureteropelvic junction obstruction in a horseshoe kidney who was successfully managed with an antegrade endopyelotomy. Follow-up at 1 year confirmed a good result. Special considerations are necessary for the successful performance of an endopyelotomy in a horseshoe kidney. Recommendations will be made regarding percutaneous access and orientation of the incision as well as a review of the literature.

Adult↗

PubMed1996

Postprostatectomy incontinence.

Post-prostatectomy incontinence is a devastating complication that is frustrating for the patient and the surgeon. Bladder dysfunction with or without sphincteric incompetence is the main cause for post-prostatectomy incontinence. Treatment based on the urodynamic evaluation is effective in restoring continence and improving the patient's quality of life.

Humans↗

PubMed1996

Increased 8-hydroxyguanine levels in DNA and its repair activity in rat kidney after administration of a renal carcinogen, ferric nitrilotriacetate.

The renal carcinogen, ferric nitrilotriacetate (Fe-NTA), is known to induce oxidative stress and the subsequent formation of a type of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), in the rat kidney (Umemura et al., 1990). Using an improved DNA isolation method (Nakae et al., 1995), which reduces the background level of 8-OH-Gua, we found a five-fold increase in the 8-OH-Gua level in kidney DNA after a single i.p. injection of Fe-NTA. On the basis of the report that 8-OH-Gua repair activity is enhanced after cells are exposed to oxidative stress due to ionizing radiation (Bases et al., 1992), the measurement of 8-OH-Gua repair activity will also be useful to assess cellular oxidative stress. The 8-OH-Gua repair enzyme activity was determined with an endonuclease assay using a 22 mer DNA that contains 8-OH-Gua at a specific position. A five-fold increase in the 8-OH-Gua repair activity as compared with the control, was observed in the target organ, the rat kidney, 120 h after Fe-NTA administration. In the non-target organ, the liver, the increase was not as large (two-fold). This simple assay of oxidative DNA damage repair will be useful for evaluating the carcinogenicity of oxygen radical forming chemicals, in addition to chemical analyses of oxidative DNA damage.

Animals↗

PubMed1996

8-hydroxyguanine levels in nuclear DNA and its repair activity in rat organs associated with age.

8-Hydroxyguanine (8-OH-Gua) is one of the most abundant types of oxidative DNA damage. The levels of 8-OH-Gua, and its repair activity, were quantified in 3-week-, 5-month-, and 30-month-old male Sprague-Dawley rat organs such as liver, kidney, spleen, lung, small intestine, and brain. The levels of 8-OH-Gua were significantly higher in the 5-month-old rat kidney and brain and 30-month-old rat spleen when compared to that of the 3-week-old rats. However, no significant differences were found in the organs between 5- and 30-month-old rats that were due to the aging process. The repair activity levels of kidney, spleen, and lung were higher than those of liver, small intestine, and brain. This pattern was consistent for the three age stages.

Aging↗

PubMed1996

Sensitive plaque assay and propagation of Chuzan (Kasba) virus, a Palyam serogroup orbivirus, in BHK-21 cells.

Various factors influencing plaque formation of Chuzan virus in BHK-21 cell monolayers were studied and a practical method for plaque assay was developed. On addition of trypsin (5 micrograms/ml) and/or diethylaminoethyl (DEAE)-dextran (50 micrograms/ml) to the virus diluent as the virus adsorption medium and agar overlay medium, the number of plaques increased. When 100 micrograms/ ml DEAE-dextran was added to the diluent and overlay medium, plaques were produced in about 10-fold higher numbers than without trypsin and DEAE-dextran. Based on these results, a practical plaque assay method for Chuzan virus was established. Using this method, one-step growth of Chuzan virus was performed at an input multiplicity of 25 plaque-forming units (PFU) per cell. Cytopathic effects were first observed at 7.5 h post-inoculation (p.i.), and were complete at 12 h p.i. The titre of cell-associated virus, after gradual decline during the first 3 h of incubation, showed a rise within 4.5 h p.i. and a rise to a plateau of 10(6.3)PFU/0.2 ml at 12 h p.i. By indirect immunofluorescence, virus-specific antigen was detected in the cytoplasm of the cells at 4.5 h p.i., and all the cells fluoresced at 6 h p.i. Haemagglutination activity was first detected in infected whole cultures at 7.5 h p.i. reaching a plateau of 1:64 at 15 h p.i. Plaque formation and haemagglutination by the virus were specifically inhibited by antisera against the original and the plaque-cloned virus.

Animals↗

PubMed1996

A method for evaluating the cariogenicity of oral bacteria using radio-labelled synthetic hydroxyapatite.

Radioactive hydroxyapatite was synthesized using 45Ca to evaluate the cariogenicity of oral streptococci. Discs prepared from it were suspended in media containing sucrose, then inoculated with Streptococcus mutans or Streptococcus sanguis. The radioactivity in the supernatant fluid was measured at specified time intervals. Released 45Ca in the supernatant fluids markedly increased in both species during the experimental period, while Strep. mutans showed much higher decalcification than Strep. sanguis. The present method would be useful for semi-quantitative evaluation of bacterial decalcification ability.

Calcium Radioisotopes↗