Biomedical subjects

M Toyoda

Publications and source records attributed to M Toyoda.

At least 145 records · Page 8Linked to original sources

PubMed1997

Long-term allograft acceptance in a patient with posttransplant lymphoproliferative disorder: correlation with intragraft viral interleukin-10.

BACKGROUND: Viral (v) interleukin (IL)-10 is expressed by Epstein-Barr virus (EBV) and has pro- and anti-inflammatory actions similar to human IL-10. EBV is also a known factor in the development of posttransplant lymphoproliferative disorder (PTLPD) in allograft recipients. We observed a patient with widespread PTLPD 9 months after renal transplantation, who subsequently maintained renal function despite minimal immunosuppression, and we investigated a possible link between these factors. METHODS: The patient's chart was reviewed for relevant history. EBV DNA in blood and tissues was assessed by polymerase chain reaction. Human and vIL-10 and gamma-interferon mRNA were evaluated with reverse transcription-polymerase chain reaction using nested primers. RESULTS: After the diagnosis of PTLPD, the patient was maintained on prednisone (8 mg/day) as the only immunosuppression with preserved renal function for 17 months until death as a result of pulmonary failure. She had continuously high blood levels of EBV DNA, although only mild persistent intrarenal atypical lymphocytic infiltrates. Human IL-10 mRNA was never present; in contrast, intragraft vIL-10 mRNA was identified and associated with resolution of an intervening episode of severe acute transplant rejection. CONCLUSIONS: We suggest that the preserved renal function resulted from the anti-inflammatory actions of vIL-10 inhibiting acute rejection in the renal allograft.

Adult↗

PubMed1997

Ureteritis and cholecystitis: two unusual manifestations of cytomegalovirus disease in renal transplant recipients.

BACKGROUND: Common clinical manifestations of cytomegalovirus (CMV) infection include flu-like symptoms with fever, diarrhea, leukopenia, and elevated liver enzymes. Diagnosis is made by detection of the virus by buffy-coat blood culture or by polymerase chain reaction (PCR) analysis. METHODS: Here we describe two renal transplant recipients who presented with unusual manifestations of CMV disease (cholecystitis and ureteritis). In both patients, no symptoms or signs of systemic CMV infection were present, and they were thought to have other common causes for cholecystitis and ureteral obstruction. RESULTS: Retrospective analysis of peripheral blood by PCR analysis was positive for CMV DNA. Histologic examination of the resected gall bladder and stenotic ureteric segment showed CMV inclusions, confirmed subsequently by in situ hybridization. Thus, we report that CMV infection may present with acute cholecystitis or ureteral obstruction without its classical clinical symptoms. CONCLUSIONS: Because CMV infection is common in transplant patients, the atypical manifestations of CMV should be considered in the differential diagnosis of posttransplant complications. Detection of CMV DNA in the peripheral blood by PCR analysis may help identify these patients.

Adult↗

PubMed1997

Correlation of cytomegalovirus DNA levels with response to antiviral therapy in cardiac and renal allograft recipients.

BACKGROUND: Cytomegalovirus (CMV) infection represents a significant morbidity factor for transplant recipients. A rapid, sensitive, specific, and reliable test is desirable for early detection of CMV infection and for monitoring the efficacy of antiviral therapy. METHODS: We examined the incidence of CMV infection in 95 cardiac and 25 renal allograft recipients followed for up to 3 years using qualitative and quantitative polymerase chain reaction (PCR) techniques. Results were subsequently correlated with clinical findings. Of the 236 samples analyzed by the CMV PCR, 84 and 20 were also analyzed by blood buffy coat culture and anti-CMV antibody IgM assays, respectively. RESULTS: The sensitivity of the CMV PCR was found to be superior to that of the other assays, although the specificity of the blood buffy coat culture is as good as that of the CMV PCR, which is higher than that of the anti-CMV antibody IgM assay. CMV infection was detected by the CMV PCR in 17 of 95 cardiac and 9 of 25 renal transplant recipients. Clinical symptoms were observed when > or =500 copies of CMV DNA/1 microg of total DNA were detected by a quantitative CMV PCR assay using an external control CMV plasmid; however, some patients had symptoms when 50-100 copies were present. The levels of CMV DNA detected varied (50-1000 copies) in patients who developed asymptomatic CMV infection. The CMV DNA levels decreased to 50-100 copies 1-2 weeks after antiviral therapy was initiated and correlated well with disappearance of clinical symptoms. CMV DNA levels decreased to < or =5 copies at 4-7 weeks after treatment. This contrasts with patients who were unresponsive to anti-CMV therapy, in whom high levels of CMV DNA (> or =500 copies) persisted for at least 5 weeks and significant levels of CMV DNA (50-100 copies) were detected for several months afterward, despite multiple courses of anti-CMV therapy. Clinical symptoms also did not disappear during this period of observation. CONCLUSIONS: (1) The CMV PCR represents a rapid, sensitive, specific, reliable test for detection of CMV infection, especially for detection of virus replication in an incipient phase. (2) The quantitative CMV PCR is useful for monitoring the efficacy of antiviral therapy to distinguish patients who respond to therapy from those who do not. (3) CMV DNA levels > or =500 copies/1 microg of total DNA analyzed by the quantitative CMV PCR can be used to differentiate CMV infection from other infections and rejection.

Cytomegalovirus↗

PubMed1997

Ultrastructural evidence for the participation of Langerhans cells in cutaneous photoaging processes: a quantitative comparative study.

Langerhans cells were studied comparatively by electron microscopy in order to explore their possible participation in cutaneous photoaging processes in chronically photodamaged preauricular skin and in paired sun-protected postauricular sites of 25 Caucasian women aged 56-76 years. The characteristic ultrastructural features of Langerhans cells in photodamaged skin compared to those in sun-protected skin were as follows: (1) a significant decrease in the density of Langerhans cells and Birbeck granules, and an increase in the number of indeterminate cells, (2) an inversely proportional relationship between intraepidermal density of Langerhans cells and the severity of epidermal photodamage, (3) frequent apposition of Langerhans cells to vacuolar structures of photodamaged keratinocytes, (4) predominant distribution of Langerhans cells in the lower epidermis, (5) degenerative changes suggesting direct cellular damage, without evidence of apoptosis, (6) a strong correlation of the number of degenerated Langerhans cells with the degree of epidermal photodamage, (7) loss of dendritic processes, (8) direct contact of Langerhans cells with melanocytes suggesting interaction between these two types of cells, (9) juxtaposition of Langerhans cells and lymphocytes in the epidermis. These results suggest marked qualitative and quantitative ultrastructural differences in Langerhans cells between photodamaged and intrinsically aged skin and the positive involvement of Langerhans cells in the processes of cutaneous photoaging.

Aged↗

PubMed1997

Selective expression of the interleukin-2 gene discriminates between the auto- and allo-mixed lymphocyte reaction.

The in vitro mixed lymphocyte reaction (MLR) is a useful model to study alloresponsiveness to histocompatibility antigens. Secretion of different cytokine proteins in the supernatant of allo-MLR cultures has been reported in a few studies with no reference to results in auto-MLR. Since most cytokines are autocrine factors, their levels in the supernatant may not reflect the actual intracellular production. Therefore, we studied cytokine gene expression in auto- and allo-MLR by Northern dot blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. mRNA for IL-beta and IL-8 was detected in both auto- and allo-MLR by Northern dot blotting. mRNA for IL-2, gamma-IFN, TNF-alpha, IL-4, IL-10 and IL-2 receptor (IL-2R) was not found by Northern dot blotting and could only be detected by RT-PCR. Expression of mRNA for IL-4, IL-10, TNF-alpha, gamma-IFN and IL-2R by RT-PCR analysis was seen in both auto- and allo-MLR. There was slightly increased expression of gamma-IFN, IL-2R and TNF-alpha in allo-MLR in comparison to auto-MLR. However, IL-2 was exclusively expressed in allo-MLR and was detected as early as 5 h of initiation of culture. These results indicate that mRNA expression for a number of cytokines can be seen in both auto- and allo-MLR using RT-PCR analysis. However, the consistent expression of IL-2 in the allo-MLR indicates that it is an important cytokine which discriminates an allo- from an autoresponse. These findings suggest that detection of IL-2 gene expression by RT-PCR may be useful for immune monitoring of allograft rejection.

Blotting, Northern↗

PubMed1997

Cytomegalovirus infection induces anti-endothelial cell antibodies in cardiac and renal allograft recipients.

Cytomegalovirus (CMV) infection represents a significant morbidity factor for transplant recipients. CMV infection has an association with the development of allograft rejection (AR) through graft endothelial cell (EC) damage, but the mechanisms are not yet clear. There are few reports addressing the role of humoral immunity in vascular EC injury mediated by CMV infection whereas many reports are available regarding the mechanism(s) of CMV-associated allograft EC injury mediated by cellular immunity. Here we examine the incidence of CMV infection in 40 cardiac and 25 renal allograft recipients using polymerase chain reaction (PCR) techniques. We also monitored sera for the development of anti-EC antibodies (AECA) using an ELISA with human umbilical vein ECs as targets, and IL-2 levels using an ELISA. AECA levels (immunoglobulin-G and immunoglobulin-M) were significantly elevated in allograft recipients who demonstrated CMV-PCR positivity when compared with the CMV-PCR negative group (IgG: 23.1 +/- 16.4 vs 4.7 +/- 4.5, p < 0.0001; IgM: 47.0 +/- 53.6 vs 7.0 +/- 11.2, p < 0.0001). Serum AECA (IgG and IgM) levels increased one to four weeks after CMV DNA was detected and elevated AECA levels persisted for at least one to two months, and sometimes for several months. Elevated AECA levels correlated well with serum IL-2 levels. These results suggest that CMV infection is associated with an increased humoral immune response to EC antigens, which may be a risk factor for vascular rejection, chronic rejection and decreased allograft survival.

Autoantibodies↗

PubMed1997

Folliculosebaceous cystic hamartoma with a neural component: an immunohistochemical study.

We present a case of follicular cystic hamartoma, a distinctive cutaneous malformation characterized by marked overgrowth of folliculosebaceous units accompanied by appreciable mesenchymal alterations, including fibroplasia, increased vascular components, and numerous adipocytes. A conspicuous feature of our case is an aggregation of thick trespassing nerve bundles in the deep portion of the neoplasm. An immunohistochemical study revealed the nerve bundles were immunoreactive for the general neuronal marker protein gene product 9.5. The nerves, however, stained negatively with antibodies against neuropeptides such as calcitonin gene-related peptide, substance P, vasoactive intestinal polypeptide, and neuropeptide Y, all of which are known to be contained in normal cutaneous nerves. The presence of these aberrant nerve bundles devoid of the normal expression of neuropeptides supports the concept that folliculosebaceous cystic hamartoma is a true, tumor-like malformation characterized by abnormal overgrowth of normal components of the skin.

Biomarkers↗

PubMed1997

Tyrosine phosphorylation sites at amino acids 239 and 240 of Shc are involved in epidermal growth factor-induced mitogenic signaling that is distinct from Ras/mitogen-activated protein kinase activation.

Epidermal growth factor (EGF) induces tyrosine phosphorylation of the Shc adapter protein, which plays an important role in EGF-stimulated mitogenesis. Shc stimulates Ras/mitogen-activated protein kinase (MAPK) through forming a complex with Grb2 at the phosphorylated tyrosine (Y) residue 317. In this study, we identified novel phosphorylation sites of Shc, at Y239 and Y240. To define the Shc pathway further, we used NIH 3T3 cells expressing the previously characterized mutant EGF receptor (EGF-R) which lacks all known autophosphorylation sites but retains EGF-stimulated mitogenesis with selective phosphorylation of Shc. We constructed wild-type (WT) or mutant Shc cDNAs in which Y317 or/and Y239 and Y240 are replaced with phenylalanine (F) and introduced them into NIH 3T3 cells expressing WT or mutant EGF-R. In the WT EGF-R-expressing cells, the Y239/240/317F Shc, but not Y317F or Y239/240F Shc, decreased EGF-stimulated cell growth. In the mutant EGF-R-expressing cells, Y317F Shc or Y239/240F Shc decreased EGF-stimulated cell growth significantly, though Y317F was a little more potent than Y239/240F. Although cells expressing the Y317F Shc hardly activated MAPK in response to EGF, cells expressing the Y239/240F Shc fully activated MAPK. In contrast, Y239/240F Shc, but not Y317F Shc, reduced the EGF-induced c-myc message. These results suggest that Shc activates two distinct signaling pathways, Y317 to Ras/MAPK and Y239 and Y240 to another pathway including Myc, and that both are involved in EGF-induced mitogenic signaling.

3T3 Cells↗

PubMed1997

[Correlations between cell proliferating activity and apoptosis in the colorectal cancer and apoptosis in the mucosa adjacent to colorectal cancer].

To investigate the growth and progression of colorectal cancer, cell production versus cell loss in colorectal cancer was examined using the proliferating cell nuclear antigen (PCNA) positivity rate and apoptotic index (AI). Cell loss was then examined using AI in the mucosa adjacent to colorectal cancer. The higher the PCNA positivity rate, the higher the apoptotic index in colorectal cancer. These results suggested that changes in cell production and cell loss may be closely correlated and play a role in the growth and progression of colorectal cancer. In patients with advanced colorectal cancer, the mucous composition of the adjacent mucosa was classified as sialomucin-predominant. Apoptosis at the proliferating zone in the mucosa adjacent to colorectal cancer (one or two glandular ducts) was also examined using the TUNEL method. This suggests that the mucosa adjacent to cancer is involved in apoptosis.

Apoptosis↗

PubMed1997

[Studies on the stability of 89 pesticides in organic solvent].

The stability of 89 pesticides (17 organochlorine, 33 organophosphorus, 8 pyrethroid, 12 carbamate, and 19 other pesticides) in 6 kinds of organic solvents (methanol, ethanol, 2-propanol, ethyl acetate, n-hexane, and acetone) was investigated using gas chromatography/mass spectrometry (GC/MS). All of the investigated pesticides were stable in all of the tested organic solvents during storage for 6 hours at room temperature in the dark except captafol, captan, phosmet, chinomethionat, and dicofol. However, the decreases of captafol, captan, phosmet, and chinomethionat were observed in methanol. The decreases of captafol, captan, and phosmet were also observed in ethanol. Moreover, the decrease of dicofol was observed in acetone. The decrease of captafol dissolved in methanol at a concentration of 2 micrograms/ml was faster than those of captan, phosmet, and chinomethionat; the residual captafol was 75% after 30 min of storage. Dicofol dissolved in acetone also decreased during storage in a refrigerator. 4,4'-dichlorobenzophenone (DCBP) and chlorobutanol were detected in the acetone solution of dicofol after storage. Furthermore, it was found that dicofol was decomposed by acetone at an injection port, and DCBP and chlorobutanol were formed when it was injected into GC with acetone.

Carbamates↗

PubMed1997

[Specific determination of deltamethrin and tralomethrin by preparative HPLC and GC-ECD].

Tralomethrin quickly changes to deltamethrin in gas chromatograph by debromination. Therefore deltamethrin and tralomethrin are not able to be distinguished by gas chromatographic determination. A method for specific determination of deltamethrin and tralomethrin was established. The method consists of fractionation by high performance liquid chromatography and determination by gas chromatography. Recoveries of deltamethrin and tralomethrin spiked to three agricultural products were from 42 to 78% and from 18 to 76%, respectively with relative standard deviations ranging from 0.3 to 15%. From the analysis of samples spiked with tralomethrin, it was found that a part of tralomethrin quickly changed to deltamethrin in homogenate of agricultural products. The addition of phosphoric acid to the homogenate did not prevent the change of tralomethrin.

Chromatography, Gas↗

PubMed1997

[Relationship between design of calibration and precision of measurement].

The method to estimate the confidence interval of calibration line was established. The method used the variance of measurement that can be predicted based on the background fluctuation. The validity of the estimated confidence interval was verified experimentally. The relationship between the calibration design and the analytical precision can be predicted with this method. The ill-designed calibration line deteriorates the trueness of the measurement as well as the precision.

Calibration↗

PubMed1996

Changes of expressions of phosphotyrosine phosphatases in rat hepatocellular carcinoma induced by 3'-methyl-4-dimethylamino-azobenzene.

Using rats with hepatocellular carcinoma induced by 3'-methyl-4-dimethylamino-azobenzene (3'-MeDAB), we evaluated the expression of a protein tyrosine phosphatase (PTPase) in the tumor region, non-tumorous region and control rat liver. The expression of SHPTP2 increased 4.1 fold (p < 0.05) in mRNA, 2.1 fold (p < 0.01) in cytosol fraction, and 5.1 fold (p < 0.05) in membrane fraction, respectively, at a protein level in the tumor region compared with control liver. The expression of other phosphatases, LAR, LRP, and PTPase1B, did not change significantly. SHPTP2 phosphatase activity in the tumor region from rats also increased compared with control, suggesting that an increase of this activity may parallel the expression of SHPTP2. This increase of expression of SHPTP2 may contribute to the progression of hepatocellular carcinoma in this rat model.

Animals↗

PubMed1996

Innervation of melanocytes in human skin.

Communication between the nervous system and epidermal melanocytes has been suspected on the basis of their common embryologic origin and apparent parallel involvement in several disease processes, but never proven. In this study, confocal microscopic analysis of human skin sections stained with antibodies specific for melanocytes and nerve fibers showed intraepidermal nerve endings in contact with melanocytes. This intimate contact was confirmed by electron microscopy, which further demonstrated thickening of apposing plasma membranes between melanocytes and nerve fibers, similar to synaptic contacts seen in nervous tissue. Since many intraepidermal nerve fibers are afferent nerves that act in a "neurosecretory" fashion through their terminals, cultured human melanocytes were stimulated with calcitonin gene-related peptide (CGRP), substance P, or vasoactive intestinal peptide, neuropeptides known to be present in cutaneous nerves, to examine their possible functions in the epidermal melanin unit. CGRP increased DNA synthesis rate of melanocytes in a concentration- and time-dependent manner. Cell yields after 5 d were increased 25% compared with controls maintained in an otherwise optimized medium. Furthermore, stimulation by CGRP induced rapid and dose-dependent accumulation of intracellular cAMP, suggesting that the mitogenic effect is mediated by the cAMP pathway. These studies confirm and expand a single earlier report in an animal model of physical contact between melanocytes and cutaneous nerves and for the first time strongly suggest that the nervous system may exert a tonic effect on melanocytes in normal or diseased human skin.

Calcitonin Gene-Related Peptide↗

PubMed1996

Free eosinophil granules in urticaria: a correlation with the duration of wheals.

To determine the factors associated with the duration of wheals in urticaria, we carried out a quantitative study of mast cells and eosinophils in both peripheral bloods and skin lesions. The percentage of cytoplasmic vacuolation, indicating a result of eosinophil degranulation of all types of specific granules of circulating eosinophils was significantly increased in the long-duration group compared with the short-duration group. Many extracellular free eosinophil granules were observed in the vicinity of disrupted eosinophils in the long-duration wheals. On the other hand, the short-duration wheals had few free eosinophil granules. The number of free eosinophil granules and the percentage of free eosinophil granules to eosinophils were significantly different between the long-and the short-duration wheals, whereas there was no significant difference between the early stage and the late stage of the long-duration wheals. The numbers of all inflammatory cells, eosinophils, and activated mast cells were increased in the late stage of the long-duration wheals. These findings suggest that free eosinophil granules liberated from infiltrating eosinophils by some stimulus may provoke the persistent activation of mast cells, and the mast-cell-derived mediators may induce the persistent state of inflammation in the long-duration wheals.

Adolescent↗

PubMed1996

Histopathological study of stromal smooth muscle cells in fibroadenoma of the breast.

Smooth muscle cells are extremely rare stromal components of fibroadenoma. Eighty-five cases of fibroadenoma were reviewed in order to investigate the frequency of smooth muscle cells and to discuss its origin. Of the 85 cases, four (4.7%) cases showed smooth muscle cells in the stroma. Distribution in terms of age and tumor size did not show any difference from other cases. Three cases were classified as an intracanalicular subtype, and one was a mastopathic subtype. The cells possessed most of the ultrastructural characteristics of smooth muscle cells, but poor indentation of nuclear contours suggested the last remnant of fibroblasts. It was therefore easy to recognize the cells derived from fibroblasts. In two of four cases, smooth muscle cells were observed in the stroma, which had marked hyalinization and calcification. Therefore, it was supposed that smooth muscle cells could appear in the stroma of long-standing tumors.

Adolescent↗

PubMed1996

Epidermal innervation correlates with severity of photodamage. A quantitative ultrastructural study.

Intraepidermal nerve fibers were studied by electron microscopy in chronically photodamaged preauricular skin and in paired sun-protected postauricular sites of 20 Caucasian women aged 56-70 years. As previously reported, basal keratinocytes in the sun-exposed skin showed various degrees of degenerative changes including intracellular vacuolar structures and widened intercellular spaces. Neurites were frequently closely apposed to basal keratinocytes in preauricular sun-exposed skin, but were observed less than 10% as often in sun-protected postauricular skin. When degree of epidermal photodamage was quantified by means of the number of degenerated keratinocytes per 100 keratinocytes in the basal layer, the number of intraepidermal nerve fibers was significantly correlated by linear regression analysis to the severity of epidermal photodamage (r = 0.913) independent of anatomical sites. These results demonstrate for the first time a correlation between degree of epidermal innervation and chronic photodamage and suggest the possibility of neural involvement in the pathophysiology and/or repair of photodamaged skin.

Aged↗

PubMed1996

Quantitative evaluation of passive cutaneous anaphylaxis (PCA) using a hand-held spectrophotometer.

A hand-held spectrophotometer was used for the quantitative evaluation of PCA caused by anti-TNP-IgE and TNP-BSA. A good relationship existed between the dilution of sera and the value of delta E*ab (a numerical expression of color) obtained by a hand-held spectrophotometer. In addition, the value of delta E*ab and the amount of Evans blue measured by the conventional colorimetric method correlated well. Because the method using a hand-held spectrophotometer provides a simple and objective analysis, it appears that the method is suitable as a substitute for the conventional method, which is time-consuming and requires killing animals cruelly.

Animals↗