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Biomedical subjects

M Kamada

Publications and source records attributed to M Kamada.

At least 109 records · Page 6Linked to original sources
PubMed1998

Overexpression of c-Met/hepatocyte growth factor receptors in human prostatic adenocarcinoma.

Hepatocyte growth factor (HGF) and c-met proto-oncogene product (c-Met) have varied biological functions in different tissues and have been implicated in mitogenic, motogenic and morphogenic responses in both organ regeneration and carcinogenesis. Some studies have suggested that the overexpression of c-Met and epidermal growth factor receptor (EGFR) are associated with growth advantage, while transforming growth factor-beta receptor II (TGF beta R II) is associated with growth disadvantage of human prostatic adenocarcinoma. However, it is unclear if the expression of c-Met correlates with the expression of EGFR and TGF beta R II, and with the proliferative status of human prostatic adenocarcinoma. Using immunohistochemical staining with anti-c-Met (C-12), anti-EGFR (NCL-EGFR) and anti-TGF beta R II (L-21) antibodies, we determined the frequency of expression of c-MET, EGFR, and TGF beta R II respectively in a series of 134 radical prostatectomy specimens. We evaluated the relationship between the expression of these receptors and clinicopathological characteristics. Overall, c-Met immunostaining was detected in 54 of 134 (40.3%) cases, EGFR in 45 (33.6%) and TGF beta R II in 64 (48.4%). The overexpression of c-Met was significantly more common in poorly differentiated (P < 0.0001) and in the diffusely infiltrated specimens (P < 0.0005). In contrast, TGF beta R II was significantly overexpressed in the well differentiated specimens (P < 0.0001) and associated negatively with c-Met (P < 0.0001). Overall, these data suggest that c-Met/HGF receptor and TGF beta R II overexpression may be involved in the differentiation of human prostatic adenocarcinoma, c-Met with de-differentiation and TGF beta R II with differentiation.

Adenocarcinoma↗
PubMed1997

IL-1 alpha induces inducible nitric oxide synthase in uterine smooth muscle.

In a previous report, we have identified interleukin-1 alpha (IL-1 alpha) in amniotic fluid of women with premature rupture of the amniotic membrane (PROM), and suggested that this cytokine may play a role in the development of the fetus. To clarify the functional role of amniotic IL-1 alpha, we studied its effect on the induction of nitric oxide (NO) synthesis in the uterus. IL-1 alpha administered intraperitoneally to rats induced an increase in the amount of mRNA encoding the macro-phage-type iNOS which was determined by reverse transcription-polymerase chain reaction. NO measurement by NO selective electrode revealed that NO production in the rat and human uterus treated with IL-1 alpha was promoted by the addition of 1 mM L-arginine to the culture medium. These findings suggest that in women with PROM, amniotic IL-1 alpha may reduce uterine contractions, in part, by inducing of iNOS.

Animals↗
PubMed1997

Pathogenicity and virulence of Rhodococcus equi in foals following intratracheal challenge.

Twelve foals, between 27 and 83 days old, were infected with 2 strains of Rhodococcus equi by intratracheal administration. Ten of the 12 foals were inoculated with 10(4)-10(10) colony forming units (cfu) of ATCC 33701 strain. The other 2 foals were inoculated with 10(9) cfu of a plasmid-cured derivative of the ATCC 33701 strain (ATCC 33701P-). All of the 10 foals challenged with the ATCC 33701 strain showed clinical signs of pulmonary disease within 5-13 days, such as gross lesions associated with acute bronchopneumonia and microscopic lesions associated with granulomatous pneumonia. The two foals challenged with the ATCC 33701P- strain showed neither clinical signs of disease nor gross lesions. Apparently, when lacking plasmid, the virulent Rhodococcus equi lost its pathogenicity.

Actinomycetales Infections↗
PubMed1997

Comparison of tracheal aspiration with other tests for diagnosis of Rhodococcus equi pneumonia in foals.

The diagnostic value of tracheal aspiration was evaluated through comparison with other diagnostic methods using an experimental model of Rhodococcus equi (R. equi) pneumonia in foals. Pneumonia was induced by spraying of the virulent R. equi strain ATCC 33701 into the trachea of foals. All foals developed fever from 11 to 16 days after bacterial inoculation. One foal was euthanized on day 26 due to its poor prognosis, and other foals euthanized on day 43. During the experiment, some tests for diagnosis of Rhodococcus equi pneumonia such as tracheal aspiration, radiography, serodiagnosis and fecal culture were carried out. R. equi was continually isolated from tracheal aspirates collected via a silicone catheter inserted transnasally on day 8 to day 32 after bacterial inoculation. On the other hand, radiography, serodiagnosis and fecal culture were demonstrated to be valuable diagnostic methods, but to be limited compared with tracheal aspiration. Indirect fluorescent antibody technique (IFA) using a monoclonal antibody against the 15- to 17-kDa virulence-associated antigens (VapA) of R. equi and PCR targeting the structural gene of VapA detected bacteria in tracheal aspirates less sensitively than the isolation technique although they were more rapid. Therefore, we conclude that a combination of tracheal aspiration and bacterial isolation was the most valuable method for routine diagnosis of R. equi pneumonia in foals.

Actinomycetales Infections↗
PubMed1997

Development of a novel octadecyl-bonded silica column and evaluation of its reliability in chromatographic analysis.

The chromatographic characterization of an octadecyl-bonded silica (ODS) column for high-performance liquid chromatography is described. In general, columns of the same type but obtained from various manufacturers give different chromatographic results, due to differences in the purity of column packings, the properties of the silica gel supports and the density of silanols on the surface of the silica gel. In order to solve this problem and to obtain a high performance ODS column, a series of methods with different samples and conditions were evaluated. The result is important for the optimization of conditions for the synthesis of ODS packings and for minimizing the deleterious effects arising from adsorption activity and metal impurity.

Acetic Acid↗
PubMed1997

Emergence of rifampin-resistant Rhodococcus equi in an infected foal.

To investigate the emergence of rifampin resistance in Rhodococcus equi strains isolated from foals and their environment in Japan, we compared the in vitro antimicrobial susceptibilities to rifampin of 640 isolates from 64 infected foals and 98 soil isolates from their horse-breeding farms. As a control, 39 human isolates from patients with and without AIDS were also tested for susceptibility to rifampin. All of the isolates showed rifampin sensitivity, except isolates from one infected foal and two patients with AIDS that showed rifampin resistance. To investigate the emergence of rifampin-resistant R. equi in the infected foal, which had received rifampin monotherapy for a month before euthanasia, 99 isolates of R. equi from the lesions and 20 isolates from the intestinal contents of the one foal with rifampin-resistant organisms were analyzed for rifampin susceptibilities, pathogenicities, and ribotypes. Of the 99 isolates from the lesions, all of which were virulent R. equi strains containing a virulence plasmid with a size of 85 or 90 kb, 90 (91%) isolates were rifampin resistant (MIC, > or = 12.5 microg/ml). On the other hand, of the 20 isolates from the intestinal contents, 11 (55%) isolates showed rifampin resistance (MIC, > or = 25 microg/ml), and 5 of them were avirulent R. equi strains. Among these 101 rifampin-resistant R. equi isolates with and without virulence plasmids characterized by ribotyping, 58 were type I, 20 were type II, 11 were type III, and 12 were type IV. These results demonstrated that at least eight different rifampin-resistant R. equi strains emerged concurrently and respectively from the different lesions and intestinal contents of the infected foal.

Actinomycetales Infections↗
PubMed1997

Coil occlusion for patent ductus arteriosus in Japan.

We surveyed Japanese experience of coil occlusion of patent ductus arteriosus up to 30 September 1996 by sending questionnaires to 175 hospitals. Thirty-four hospitals reported outcome data for 231 procedures in 218 patients. Successful implantation was achieved in 94% and acute complete closure of the ductus occurred in 71% of those in whom implantation of the coil was successful. Of the latter, 83% reported late complete closure. When those patients who underwent reocclusion for residual shunt are included, 89% attained complete closure. No life-threatening complications have occurred so far. Late reopening was reported in 3 cases. Although the angiographic type of ductus was significantly related to successful implantation (p < 0.01), there was no significant correlation with complete occlusion. Ductuses with a minimum diameter greater than 3 mm had a decreased chance of successful implantation, whereas those less than 2 mm had a greater incidence of complete closure.

Child↗
PubMed1997

Genetic analysis of equine methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis (PFGE) was used to determine genetic relationships among 15 methicillin-resistant Staphylococcus aureus (MRSA) isolates from mares with metritis and from a stallion with dermatitis in Hokkaido. All the 15 isolates showed phage pattern 6/47/54/75, coagulase type IV, and enterotoxin type A. The restriction endonuclease SmaI cut their genomic DNAs into 15 or 16 fragments ranging in size from 8 to 630 kb. Fourteen of the 15 isolates showed the same PFGE pattern, whereas the remaining one appeared to be closely related. The 9 human MRSA isolates showing the same phenotypic characteristics as the horse isolates gave different PFGE patterns from those of the horse isolates.

Animals↗
PubMed1997

[Successful open commissurotomy and resection of dysplastic myxomatous tissue on the leaflet edges in a neonate and an early infant with critical aortic stenosis].

A neonate and an early infant with critical aortic stenosis successfully underwent open commissurotomy and resection of dysplastic myxomatous tissue on the leaflet edges using cardiopulmonary bypass. Case 1: A 31-day-old boy admitted to our unit with shock. Echocardiography demonstrated critical aortic stenosis and severe left ventricular dysfunction (EF = 15%). Case 2: A 12-day-old boy suddenly deteriorated and required resuscitation with ventilation and inotropic support. Emergency operation was required in both cases using cardiopulmonary bypass with systemic hypothermia (30 degrees C). In both cases, the aortic valve was bicuspid and dysplastic with gelatinous myxomatous tissue on the leaflet edges. Commissurotomy and resection of myxomatous tissue were performed. Their postoperation courses were uneventful and they have been free from medication at present. These results suggest that aortic commissurotomy and resection of myxomatous tissue under direct vision may be preferable for critical aortic stenosis with dysplastic aortic valve.

Aortic Valve↗
PubMed1997

Immunological functions of adult T cell leukemia cells of a patient complicated with synchronous double primary gynecologic cancer.

A patient with triple malignancies is reported, who presented cervical cancer, vulvar cancer and adult T cell leukemia (ATL). ATL was diagnosed as a smouldering type, because antibody to human T cell leukemia virus associated antigen (ATLA) was positive with a titer of 1:160. Although her malignant cells had an OKT 4+8-3+Tac+ phenotype, the cells did not display helper T cell functions. Namely they showed no response to Phytohemagglutinin (PHA) and Interleukin 2 (IL-2) and suppressed the PWM driven IgG synthesis of B cells obtained from healthy donor. They did not produce IL-2 by stimulation with PHA and phorbol myristate acetate (PMA). Furthermore, these ATL cells were producing IL-2 inhibitor like factors. As synchronous triple malignancies are extremely rare, two gynecologic cancers seem to ascribe to the suppressing state of the immunosurveillance mechanism by viral infection.

Aged↗
PubMed1997

[Estrogen, progesterone--biosynthesis, receptor and action].

Ovarian sex steroid hormones, estrogen and progesterone, have crucial effects on female reproductive functions such as the development and maturation of reproductive organs and the appearance of normal menstrual cycles. The precursor of steroid hormones is a cholesterol that is synthesized de novo from acetate or that is taken in as LDL-cholesterol via LDL-receptor. Members of cytochrome P450 superfamily and hydroxysteroid dehydrogenase (HSD) involved in the biosynthesis of the steroid hormones. In the corpus luteum, P450scc and 3 beta-HSD catalyze the pathway from cholesterol to progesterone and in the granulosa cells, P450arom (aromatase) and two HSDs catalyze the biosynthesis of estrogen from C19 steroid synthesized in the theca cells having P450(17) alpha. In the target cell, steroid binds to and activates its receptor located primarily in the nucleus. Binding of ligand results in dimerization of the receptor due to its conformational change. The steroid-receptor complex binds to specific hormone responsive element of the target gene at the site of DNA binding region and then activates transcription of the gene. Main action of estrogen is to stimulate the proliferation and development of cells due to enhancement of the synthesis of specific DNAs and proteins in the female reproductive organs. Progesterone regulates the action of estrogen through the decrease of estrogen receptor and down regulation of its own receptor.

Estrogens↗
PubMed1996

Expression of Tn and sialyl-Tn antigens in the neoplastic transformation of uterine cervical epithelial cells.

The expression of simple mucin-type carbohydrate antigens, Tn and sialyl-Tn antigens, was evaluated by immunohistochemical staining with monoclonal antibodies in normal squamous epithelium, dysplasia, carcinoma in situ, and invasive squamous cell carcinoma of the uterine cervix. The expression of the Tn antigen detected by HB-Tn1 and B1.1 was found in 17 (20%) and 19 (23%) of the 83 invasive carcinomas, respectively, but was not found in the 36 normal squamous epithelia, 22 severe dysplasias, or 24 carcinomas in situ. The sialyl-Tn antigen was detected by HB-STn1 and TKH-2 in 14 (64%) and 11 (50%) of the 22 severe dysplasias, 13 (54%) and 10 (42%) of the 24 carcinomas in situ and 48 (58%) and 42 (51%) of the 83 invasive carcinomas, respectively, but was completely absent in 36 normal squamous epithelia. Coexpression of the sialyl-Tn antigen was observed in 89% of the cases expressing the Tn antigen. No significant difference was observed between the immunoreactivities of the antigens in the metastatic lymph nodes and primary tumors. No correlation was found between the expression of each antigen and clinical state, histologic type, depth of invasion, parametrial spread, lymphatic and vessel permeation, lymph node metastasis, or 5-year survival rate. The expression of Tn and sialyl-Tn demonstrates a specific change in the neoplastic progression from carcinoma in situ to invasive carcinoma and from normal to dysplasia, respectively, in squamous cell neoplastic lesions of the cervix. Tn and sialyl-Tn antigens may be useful markers for biologic investigation of neoplastic transformation in cervical squamous cell carcinoma.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1996

Late aneurysm after subclavian flap aortoplasty for coarctation of the aorta.

Late aneurysms are common after repair of coarctation of the aorta by prosthetic patch aortoplasty but are rare after subclavian flap aortoplasty. We present the case of a 14-year-old boy who underwent a grafting procedure for a descending thoracic aortic aneurysm after subclavian flap aortoplasty for coarctation of the aorta when he was 2 years old. This is the fifth report of late aneurysm formation after subclavian flap aortoplasty.

Adolescent↗
PubMed1996

Inducible nitric oxide synthase in uterine smooth muscle.

The expression of inducible nitric oxide synthase (iNOS) mRNA in rat uterus upon in vivo stimulation with lipopolysaccharide (LPS) was studied by reverse transcription and polymerase chain reaction. The injection of LPS induced an increase in mRNA levels of a macrophage-type iNOS. In unstimulated rats, low levels of iNOS mRNA was detected in the uterus and lungs, but absent or negligible in the kidneys and liver. NO was produced in the LPS-treated uterus by addition of 1 to 1000 microM L-arginine. The production of NO in uterine tissue that faces the outside of the body may provide a bacteriocidal protective function against microorganisms in physiological condition. However, NO produced in a large amounts by cytokine and LPS may play some pathological reaction during septic shock or infection.

Animals↗
PubMed1996

Lack of virulence of the murine fibroblast adapted strain, Kentucky A (KyA), of equine herpesvirus type 1 (EHV-1) in young horses.

The virulence of the cell culture adapted KyA strain of equine herpesvirus type 1 (EHV-1), which lacks at least six genes by deletions in its genome, was assessed by intranasal inoculation of six young horses that were serologically negative for EHV-1. No horses showed clinical signs, and a neutralizing antibody response against EHV-1 was detected in two horses which had antibodies against EHV-4 prior to the inoculation. A challenge experiment using a highly virulent strain of EHV-1 conducted 4 weeks later against 4 of the 6 horses inoculated intranasally with the KyA strain and 2 control horses revealed that (i) the KyA inoculated horses were protected from manifestation of clinical signs detected in both control horses, with the exception of pyrexia, (ii) duration of virus isolation from the KyA inoculated horses after the challenge was remarkably shortened as compared to that from control horses; (iii) thus, animals inoculated with the KyA and challenged with pathogenic EHV-1 showed a reduction in the time of virus shedding and viremia; (iv) two horses which exhibited no antibody responses after the KyA inoculation showed antibody responses after the challenge significantly higher than those of control horses. The results reveal that the KyA strain has no virulence but still possesses immunogenicity for horses, suggesting that some of the genes deleted from the KyA strain might have importance in the expression of EHV-1 virulence.

Animals↗
PubMed1996

Serum antibody responses of foals to virulence-associated 15- to 17-kilodalton antigens of Rhodococcus equi.

Humoral immune responses in 16 foals to virulence-associated 15- to 17-kDa antigens of Rhodococcus equi were studied during the first fourteen weeks of life on two horse-breeding farms with a persistent incidence of R. equi infection. Serum antibody levels specific for 15- to 17-kDa antigens were measured by enzyme-linked immunosorbent assay and Western immunoblotting. Immunoglobulin G (IgG) antibodies specific to 15- to 17-kDa antigens were detected by all the foals. R. equi was found in the feces of foals during week 1 of life, and the number of fecal R. equi rapidly increased to the highest level. Virulent R. equi were isolated from the feces of the foals at a high frequency and from their environmental soil on the farms. Evidence that serum antibody response to 15- to 17-kDa antigens of virulent R. equi occurred naturally in every foal in correlation with the quantitative changes of fecal R. equi during the first 1 to 3 months of life suggests that intestinal virulent R. equi might be the most important source of antigenic stimulation in foals from contaminated farms.

Actinomycetales Infections↗
PubMed1996

Effect of IL-1 in amniotic fluid on the fetal keratinocyte.

IL-1 alpha is predominantly increased in amniotic fluid of the patients with premature rupture of the membrane (PROM). In the present study we examined the effect of IL-1 on the fetal keratinocytes, one of the main tissue exposed to the increased IL-1. Exposure of IL-1 at over 0.1 pg/ml IL-1 significantly (p < 0.01) inhibited proliferation of the keratinocytes in low calcium keratinocyte growth medium obtained from the umbilical cord. Immunohistochemical analysis using antibodies to various cytokeratins revealed that the umbilical cord keratinocytes is more similar to the mucosal epithelium than the skin epithelium. These results suggest that IL-1 alpha increased in amniotic fluid in the PROM cases leads the immature proliferating mucosal epithelium to maturate for protection of the fetus against environment.

Amniotic Fluid↗