Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 199 records · Page 11Linked to original sources

PubMed2000

Successfully treated descending necrotizing mediastinitis through mediansternotomy using a pedicled omental flap.

A 21-year-old man with an oropharyngeal abscess admitted to our institution was initially treated with systemic antibiotics but was referred to our department when his condition rapidly deteriorated. His respiratory insufficiency required circulatory support. A computed tomographic scan showed a parapharyngeal abscess descending into the mediastinum with multiple right-side capsulized empyema and pericardial effusion. We conducted emergency surgery through a mediansternotomy using a pedicled omental flap. Postoperative clinical and radiologic assessment showed a normal chest X-ray and primary wound healing without sternal dehiscence. Mediansternotomy using a pedicled omental flap offers excellent exposure for a complete one-stage operation with debridement of all affected tissues of the subauricular region, the mediastinum, and both pleural cavities. We conclude that this method yields good results for patients with acute widespread descending necrotizing mediastinitis.

Adult↗

PubMed2000

Expression of blood group antigens A, B and H in carcinoma tissue correlates with a poor prognosis for colorectal cancer patients.

The deletion of blood group ABH isoantigens on tumor tissues has been reported to be an adverse prognostic marker for patients with various solid tumors. In the present study, we evaluated the prognostic value of altered expression of ABH isoantigens in colorectal carcinomas. Using monoclonal antibodies, the expression of A, B, and H antigens was assessed by immunohistochemistry on paraffin-embedded carcinoma samples from 82 patients who had undergone surgery for colorectal cancer. ABH isoantigens were found to be deleted in 36 carcinomas (43.9%) and expressed in 46 (56.1%). Univariate and multivariate analysis using a logistic regression model revealed that N factor (lymph node metastasis) and blood group type were independently related to the expression of ABH isoantigens. In contrast to previous reports on other cancers, patients whose colorectal carcinomas express ABH isoantigens had a poorer prognosis than those whose carcinomas showed deletion of ABH isoantigens (P = 0.0008). The expression of ABH isoantigens was an independent prognostic variable, in addition to T (depth of tumor invasion), N, and M (distant metastasis) factors, as shown by means of Cox regression analysis. In conclusion, the expression of ABH isoantigens in carcinoma tissue is an important poor prognostic factor in patients with colorectal cancer. This variable needs to be considered in the design of future trials of therapy.

ABO Blood-Group System↗

PubMed2000

X-ray fluorescence analysis of trace metal ions following a preconcentration of metal-diethyldithiocarbamate complexes by homogeneous liquid-liquid extraction.

A homogeneous liquid-liquid extraction method for 36 metal ions with diethyldithiocarbamate was studied. As a result, 11 metal ions were extracted as metal-chelates. Under the experimental conditions, the maximum concentration factor was 500 (i.e., 0.1 mL of sedimented liquid phase was produced from 50 mL of aqueous phase). Moreover, the proposed method was utilized as a preconcentration method for X-ray fluorescence analysis of these metals. The recovery of each metal was ca. 97-100%. All calibration curves were linear over the range of 5.0 x 10(-7) mol L-1 to 1.0 x 10(-5) mol L-1. The detection limits were at the 10(-8) mol L-1 levels and the relative standard deviations were below 5% (5 determinations). When the proposed method was used for the determination of contaminants in a synthetic sample (Al-based alloy model) and of components in an Au-Pd alloy, the results were satisfactory.

Journal Article↗

PubMed2000

The management of pelvic chondrosarcoma in Japan. Japanese Musculo-Skeletal Oncology Group.

A review of 135 patients with pelvic chondrosarcoma who had been treated at 58 institutions in Japan between 1989 and 1998. In this series ablative surgery was necessary in 14 patients, and a limb salvage procedure performed in 121 patients. The surgical margins were "intra-lesional" in 27 patients, "marginal" in 30, "wide" in 77 and "unspecified" in 1. Local recurrence occurred in 33 patients and distant metastases in 25. Post-operative infection occurred in 25 patients. Revision was performed in 10 patients. The oncological outcome was "disease free" in 92 patients, "alive with disease" in 17 and "dead because of the disease" in 26. The cumulative prospective 10-year survival rate for all patients was 65%. The 6 statistically significant prognostic factors that determined the outcome were: - surgical stage, site of tumour, size of tumour, surgical margin, functional mobility and activity level after surgery. Excision of the tumour with a wide margin, or with a wide margin with partly marginal areas, and subsequent stable reconstruction are essential for improving the results of pelvic chondrosarcoma treatment.

Acetabulum↗

PubMed2000

A case of chronic myeloid leukemia with minor bcr-abl transcript following fluorouracil therapy for esophageal carcinoma.

We report here a very rare case of chronic myeloid leukemia (CML) with a minor bcr-abl transcript, which developed following long-term chemotherapy with fluorouracil for esophageal carcinoma. A 64-year-old male patient was diagnosed with CML. Four years earlier, he had suffered from esophageal carcinoma, which was treated by surgical resection followed by oral administration of fluorouracil (200 mg/day) for 4 years. Molecular analysis of his Philadelphia chromosome (Ph) using reverse-transcriptase polymerase chain reaction (RT-PCR) and subsequent sequencing revealed a minor bcr-abl transcript. The clinical course of this patient was aggressive with a short chronic phase of CML. This is the first reported case of secondary CML with a minor bcr-abl transcript.

Esophageal Neoplasms↗

PubMed2000

Amyloid beta-protein (Abeta)-containing astrocytes are located preferentially near N-terminal-truncated Abeta deposits in the human entorhinal cortex.

The deposition of the amyloid beta-protein (Abeta) is a pathological hallmark of Alzheimer's disease (AD). Abeta is a peptide consisting of 39-43 amino acids and is derived by beta- and gamma-secretase cleavage from the Abeta protein precursor (AbetaPP). An N-terminal-truncated form of Abeta can occur following alpha- and gamma-secretase cleavage of AbetaPP. Fleecy amyloid is a recently identified distinct type of Abeta deposits occurring in the internal layers (pri-alpha, pri-beta and pri-gamma) of the human entorhinal cortex. Fleecy amyloid consists exclusively of N-terminal-truncated Abeta and is a transient form of Abeta deposits, which disappears in late-stage beta-amyloidosis. In this study, the entorhinal cortex of 15 cases with AD-related pathology was used to examine astrocytes in the vicinity of N-terminal-truncated Abeta in fleecy amyloid of the layers pri-alpha, pri-beta, and pri-gamma in comparison to astrocytes in the vicinity of full-length Abeta in layers pre-beta and pre-gamma. Immunohistochemistry was performed with antibodies directed against AbetaPP, Abeta40, Abeta42, APbeta17-24, Abeta1-17 and Abeta8-17 as well as by double-labeling with antibodies directed against Abeta17-24, Abeta42, and glial fibrillary acid protein (GFAP). A large number of GFAP-positive astrocytes containing N-terminal-truncated Abeta fragments appeared in the vicinity of N-terminal-truncated Abeta, whereas Abeta-containing astrocytes were rarely seen in the vicinity of full-length Abeta. These results suggest that N-terminal-truncated Abeta peptide may be cleared preferentially from the extracellular space by astrocytic uptake and processing. Such an astroglial uptake of N-terminal-truncated Abeta may account for the transient nature of fleecy amyloid and point to the use of N-terminal truncation of Abeta in potential therapeutic strategies aimed at preventing the brain from amassing full-length Abeta deposits.

Aged↗

PubMed2000

Age-related plaque morphology and C-terminal heterogeneity of amyloid beta in Dutch-type hereditary cerebral hemorrhage with amyloidosis.

The evolvement of amyloid beta (Abeta) deposition in the frontal cerebral cortex of 24 patients of increasing age with Dutch-type hereditary cerebral hemorrhage with amyloidosis (HCHWA-D) was studied using end-specific monoclonal antibodies to Abetax-42 (Abeta42) or Abetax-40 (Abeta40) and markers for degenerating neurites. Abeta42 immunostaining revealed parenchymal Abeta deposits with a heterogeneous morphology and distribution, i.e., clouds, fine/dense diffuse, coarse, and homogeneous plaques. Clouds and diffuse plaques were associated with glial Abeta granules. Abeta40 labeling was absent in clouds/fine diffuse plaques, inconsistent and variably intense in dense diffuse/coarse plaques and consistent in homogeneous plaques. In a subset of Abeta40-positive plaques, degenerating neurites--without tauopathy--and/or amyloid cores were observed. Electron microscopy revealed no apparent amyloid fibrils in fine diffuse plaques, small bundles of fibrils in dense diffuse/homogeneous plaques, and amyloid masses in coarse plaques. The parenchymal Abeta pathology was age-related: the ratio of fine to dense diffuse plaques decreased with age, clouds were limited to younger patients; coarse plaques to the oldest old. Homogeneous/cored plaques were present most consistently in older patients. Plaque density did not increase with age. Vascular Abeta deposits stained for both Abeta species, but exclusively Abeta42-positive, presumably recent deposits were also observed. This study suggests that HCHWA-D is a model of plaque evolution in which clouds leave fine diffuse plaques, which may become dense diffuse and ultimately coarse or homogeneous plaques.

Adult↗

PubMed2000

The relationship between circulating sialyl Tn antigen and polypoid or nonpolypoid growth characteristics in colorectal cancer.

Recent studies delineated two different patterns of tumor growth in colorectal carcinoma characterized as polypoid and nonpolypoid (PG-type and NPG-type, respectively). We quantified serum sialyl Lewis (Le)a (CA19-9), sialyl Lex (SLX), sialyl Tn (STN), and carcinoembryonic antigen (CEA) in 269 colorectal cancer patients to establish whether their levels correlated with any biological or clinical differences between PG-type and NPG-type cancer. Patients were divided into high and low antigen groups (higher or lower than a selected diagnostic-based cut-off value) and compared. Statistical testing was by univariate and multivariate (logistic regression) analyses. Forty-seven (17.5%) patients with PG-type and 222 (82.5%) with NPG-type cancer were studied. In contrast to NPG-type, the characteristics of the PG-type cancers included a low rate of lymph node metastasis and a high serum STN level. In contrast to a low STN level, a high STN level was independently related to the presence of distant metastasis in patients with PG-type cancer, and also to the presence of distant metastasis and large-sized tumor in patients with NPG-type cancer. These data suggest that differences in STN levels in the serum of patients with PG-type or NPG-type colorectal carcinomas may be at least partly responsible for different tumor progression behavior.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed2000

Autoimmune reactivity of sera to hepatocyte plasma membrane in type 1 autoimmune hepatitis.

Type 1 autoimmune hepatitis (AIH-1) is an organ-specific autoimmune liver disease for which no tissue-specific autoantigen has yet been identified. We examined the reactivity by sensitive immunoblotting with enhanced chemiluminescence (IB-ECL) of 43 sera from patients with AIH-1 and 182 sera from patients with other diseases on hepatocyte plasma membrane derived from rat or human liver (RHPM, HHPM) and separated by aqueous two-phase partition. The sera studied were from patients with AIH-1, primary biliary cirrhosis, chronic viral hepatitis, and systemic lupus erythematosus (SLE); and from normal subjects. Specificity of reactivity by IB-ECL was sought: (i) by testing sera on human or rat liver membrane; (ii) by testing sera on liver or kidney membrane; (iii) by serial titration of reactive sera; and (iv) by testing reactive sera from AIH-1 before and after successful treatment with prednisolone. The results were that in AIH-1 there were multiple reactive components which were not species-specific, since they were detected with both RHPM and HHPM, but were mostly tissue-specific for liver. There was no significant correlation between antinuclear antibodies (ANA) titer and the frequencies of sera reactivities against RHPM. Most of these reactive components were demonstrable at a lesser frequency in other liver diseases and in SLE. There was a striking decrease in reactivity by IB-ECL of AIH-1 sera with liver membrane after clinical remission, further suggesting that differences between AIH-1 and other inflammatory liver diseases and SLE are predominantly quantitative rather than qualitative. However, our study did point to candidate liver membrane antigens with molecular sizes of 136, 116, 81, and 49 kDa, additional to components previously described by others. The molecular identification of these prominent reactants with AIH-1 sera could prove informative for ascertaining pathogenesis.

Adult↗

PubMed2000

Carcinoma of the splenic flexure: multivariate analysis of predictive factors for clinicopathological characteristics and outcome after surgery.

The clinicopathological characteristics and outcome of splenic flexure cancer after surgery have yet to be fully elucidated. The aim of the current study was, therefore, to establish predictive factors related to splenic flexure cancer and outcome after surgery. We compared the clinicopathological characteristics and outcome of 34 patients with splenic flexure cancers (which represents 3.7% of the total number of colon cancers in our series) with those of 418 patients with right colon and 475 patients with left colon cancers by univariate and multivariate analyses, using logistic regression analysis and Cox's proportional hazards model. Splenic flexure cancers had a high risk of obstruction (26.5% of patients), and had a more advanced stage and lower cure rate than left colon cancers. Logistic regression analysis revealed that two independent factors, colonic obstruction and the presence of distant metastases, were related to the splenic flexure tumor site. Splenic flexure cancer patients had a poorer outcome than those with left colon cancer (P = 0.0361). However, there was no difference in survival between patients with splenic flexure, those with right colon cancer and those with left colon cancer who underwent curative surgery. Cox's regression analysis revealed that neither the site of splenic flexure nor colonic obstruction was an independent prognostic factor. In conclusion, splenic flexure cancer is characterized by a high risk of obstruction and the presence of distant metastases. However, after curative resection, splenic flexure cancer has a similar outcome to colon cancer at other sites. In addition, neither the splenic flexure site nor colonic obstruction had an independent influence on patient survival after surgery.

Colonic Neoplasms↗

PubMed2000

Characteristic biological effects of itraconazole on L929 fibroblasts and their cell membrane.

Itraconazole (ITCZ), a triazole antifungal agent, was studied for its effects on the morphology and function of L929 fibroblasts. L929 fibroblasts were cultured for 20 h with ITCZ or one of several other triazoles (fluconazole, ketoconazole, and hydroxy-itraconazole [ITCZ-OH]) at the concentration of 0.5 microg/ml. Among these agents, only ITCZ and its metabolite ITCZ-OH markedly elongated the cells bidirectionally. Scanning electron microscopy studies showed that the surface of the elongated cells was smoother than that of the untreated cells. The viability of L929 cells cultured with 0.5 microg/ml of ITCZ for 20 h was not lowered. However, after treatment with 0.0375% sodium deoxycholate (DOC) solution, the viability of the cells treated with ITCZ, as evaluated by the 3-(4,5-dimethyl-2thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) proliferation assay or the release of lactic dehydrogenase from cytoplasm, was decreased. When L929 cells were cultured in the presence of a combination of ITCZ and vincristine, their growth was synergistically inhibited. This synergism was also observed when ITCZ was replaced by ITCZ-OH, but not by the other azoles. These findings suggest that the exposure of L929 fibroblasts to low ITCZ concentrations affects the physiological nature of their cell membrane.

Animals↗

PubMed2000

Comparison of the therapeutic efficacy of oral doses of fluconazole and itraconazole in a guinea pig model of dermatophytosis.

The therapeutic efficacy of orally administered fluconazole (FLCZ) and itraconazole (ITCZ) in a guinea pig model of dermatophytosis was compared, using the infection intensity of local skin tissue as an index. After Trichophyton mentagrophytes infections had been established in the test animals, the antifungal agents were administered once per day for 14 days. FLCZ had a dose-dependent therapeutic effect and significantly ameliorated infections at doses of 10 and 20 mg/kg per day (both P < 0.01) compared with the untreated control group. The pathogen could not be cultured from previously infected skin tissue from 11% of the animals treated with FLCZ at 10 mg/kg per day, and from 20% of the animals treated with FLCZ at 20 mg/kg per day. The therapeutic efficacy of FLCZ was approximately equal to that of ITCZ administered at the same doses. These results suggest that FLCZ may be a useful treatment for dermatophytosis.

Administration, Oral↗

PubMed2000

Differences in release mechanisms and distributions for sialyl Le(a) and sialyl Le(x) antigens in colorectal cancer.

BACKGROUND: To investigate colorectal cancer-related carbohydrate antigen release and distribution, we evaluated serum levels of sialyl Le(a) (CA19-9) and sialyl Le(x) antigen (SLX) in blood samples obtained from both a peripheral vein and a tumor's draining vein. METHODS: Blood samples were obtained during surgery from 126 patients. Based on these samples, patients were placed into a high-antigen group, with a concentration above a selected cutoff value, or into a low-antigen group, with a tumor marker concentration below that same value. The blood samples obtained from peripheral veins were designated by the "p" prefix, and samples from drainage veins were designated by the "d." RESULTS: Serum d-SLX levels were significantly higher than p-SLX levels (P < .0001), although there was no difference between those of d-CA19-9 and p-CA19-9. Only 1 (3.6%) of 28 patients in the high d-CA19-9 group had a low p-CA19-9. In contrast, 6 (33.3%) of 18 patients in the high d-SLX group had low p-SLX levels (P = .0103). Correlations between pathological variables and either p-CA19-9 levels or d-CA19-9 levels were similar. However, both distant metastasis and venous invasion did prove to be independent variables related to d-SLX levels, as shown by logistic regression analysis. CONCLUSIONS: SLX may drain predominantly via the draining veins of colorectal tumors into portal circulation, whereas CA19-9 may drain via another route.

Aged↗

PubMed2000

Effect of apolipoprotein E allele epsilon4 on the initial phase of amyloid beta-protein accumulation in the human brain.

Deposition of amyloid ss-protein (Ass), a hallmark of Alzheimer's disease, occurs to some extent in the brains of most elderly individuals. We sought to learn when Ass deposition begins and how deposition is affected by apolipoprotein E allele epsilon4, a strong risk factor for late-onset Alzheimer's disease. Using an improved extraction protocol and specific enzyme-linked immunosorbent assay, we quantified the levels of Ass40 and Ass42 in the insoluble fractions of brains from 105 autopsy cases, aged 22 to 81 years at death, who showed no signs of dementia. Ass40 and Ass42 were detected in the insoluble fractions from all of the brains examined; low levels were even found in the brains of patients as young as 20 to 30 years of age. The incidence of significant Ass accumulation increased age-dependently, with Ass42 levels beginning to rise steeply in some patients in their late 40's, accompanied by much smaller increases in Ass40 levels. The presence of the apolipoprotein E epsilon4 allele was found to significantly enhance the accumulation of Ass42 and, to a lesser extent, that of Ass40. These findings strongly suggest that the presence of epsilon4 allele results in an earlier onset of Ass42 accumulation in the brain.

Adult↗

PubMed2000

Expressions of amyloid precursor protein, synaptophysin and presenilin-1 in the different areas of the developing cerebellum of rat.

This study reveals the expressions of Alzheimer's disease-related amyloid precursor protein, presenilin-1, and a presynaptic marker protein, synaptophysin, in the archi-, paleo- and neocerebellum during the postnatal development of the rat. The Western blot results demonstrate a gradual increase in the soluble amyloid precursor protein level in the archicerebellum during the first 3 weeks, while in the neo- and paleocerebellum the levels reach a plateau as early as the 1st week. Immunohistochemically, the protein is present in the deep part of the external granule cell layer and the internal granule cell layer in the newborn animal, while in 3-week-old animals the staining appears mainly in the perikarya and dendrites of the Purkinje cells. The level of synaptophysin increases progressively from postnatal day 7 up to 3 weeks in the archi- and paleocerebellum, and up to 6 weeks in the neocerebellum. Immunohistochemically, the amyloid precursor protein staining appears first in the inner part of the molecular layer and in the internal granule cell layer. In a 3-week-old animal, synaptophysin staining is present in all areas of the cerebellar molecular layer and in the internal granule cell layer. The presenilin-1 immunohistochemical reaction appeared equally in the archi-, paleo- and neocerebellum. Much of the staining is present in the glial cells and Purkinje cells. Less immunoreactivity is observed in the Golgi cells and granule cells. It is concluded that the postnatal expressions of soluble and membrane-bound amyloid precursor protein, synaptophysin and presenilin-1 are regulated differently during the ontogenetical development of the archi-, paleo- and neocerebellum of rat. Further, the amyloid precursor protein and presenilin-1 may be present in cells which do not degenerate in Alzheimer's disease.

Aging↗

PubMed2000

The role of cognitive cueing in eliciting vocal variability.

Variation in duration and frequency during three readings of each of eight sentences by 9 normal and 4 voice-disordered subjects are compared. Instructions to the subjects varied with respect to the amount and type of cognitive cueing presented in the trials, and the sentences were read in random order. Variability in fundamental frequency (F0) was greater when pitch variation was specifically cued. Also, the portion of the sentence that was cued had greater variability in F0 than other parts of the sentence. Variation in fundamental frequency was significantly greater in the cued versus uncued sentence trials for the voice-disordered subjects but not for the normal subjects. However, all subjects exhibited significantly greater duration for cued versus uncued readings of the same sentences. Implications for theory and practice are discussed.

Adult↗

PubMed2000

Effects of stimulation techniques on vocal responses: implications for assessment and treatment.

During voice evaluation and treatment it is customary for clinicians to elicit samples of the vowel /a/ from clients using various elicitation techniques. The purpose of this study was to compare the effects of four commonly used stimulation tasks on the laryngeal mechanism. Eleven female singing students, studying at a university music school, served as subjects for the study. The subjects phonated the vowel /a/ using 4 vocal stimulation techniques: yawn-sigh, gentle onset, focus, and the use of the voiceless fricative. Videoendoscopic and acoustic evaluations of their productions were done. Results show that, in the first 100 ms following the end of the formant transition, these techniques affected voice differently. The fundamental frequency was found to be highest in the yawn-sigh condition, whereas the maximum frequency perturbation was obtained for the voiceless fricative condition. Planned comparisons were made by comparing the data across 2 dimensions: (1) vowels elicited with voiced contexts versus those elicited with voiceless consonantal contexts and (2) vowels elicited with obstruent versus vowels elicited with nonobstruent consonantal contexts. Some changes in acoustic parameters brought about by these stimulation techniques may be explained on the basis of coarticulatory effects of the consonantal context.

Adolescent↗

PubMed2000

The activity of fatty acid synthase of epidermal keratinocytes is regulated in the lower stratum spinousum and the stratum basale by local inflammation rather than by circulating hormones.

The epidermal keratinocytes produce and secrete lipids to maintain the water barrier of the epidermis. To clarify the regulation of epidermal lipid synthesis, we investigated the hormonal effect on the activity of fatty acid synthase (FAS) of the keratinocytes, and the expression of FAS in the human skin. In cultured keratinocytes, the FAS activity, assayed by measuring the oxidation of NADPH, was slightly increased by hydrocortisone or testosterone, but not influenced by thyroid hormone, estrogen, progesterone or insulin. In immunohistochemical study of normal human epidermis, FAS was expressed strongly in the stratum granulosum and moderately in the uppermost layer of the stratum spinousum (SS), suggesting that fatty acid synthesis may increase during normal epidermal differentiation. In inflammatory disorders, such as psoriasis, lichen planus, and atopic dermatitis, FAS was also expressed in the lower SS and the stratum basale (SB), resulting in strong staining in the whole layers of the epidermis. Remarkable increase of FAS expression was only observed in the lower SS and the SB. Therefore, the activity of FAS in the epidermis may be regulated in the lower SS and the SB by local inflammation rather than by circulating hormones. In other components of the skin, FAS was strongly expressed not only in adipose tissue and sebaceous glands, which are known as active sites of lipid synthesis, but also in sweat glands, suggesting that the sweat glands can synthesize abundant fatty acids de novo.

Antibodies↗