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Biomedical subjects

H Toma

Publications and source records attributed to H Toma.

At least 73 records · Page 4Linked to original sources
PubMed2001

Electrovaporization using a rollerball electrode for flat or small papillary tumors of the bladder: basic study in dogs.

PURPOSE: We investigated electrovaporization of flat bladder tumors with a rollerball electrode 3 mm in diameter as a substitute for conventional transurethral resection with a cutting loop. MATERIALS AND METHODS: A basic study of the action of electrovaporization was performed in dogs. The bladder was exposed under general anesthesia in three mongrel dogs. The rollerball electrode was attached to the resectoscope and inserted into the bladder via a cystostomy. Then electrovaporization was performed with a low or high pressure on the electrode tip and a speed of about 1 cm/sec using a Force 40 generator. The cutting mode power was set at 100 W or 200 W. The effects of the rollerball and cutting loop electrodes were also examined in the coagulation mode (45 W) as a control. RESULTS: A deeper vaporization zone was obtained by using a power of 200 W in the cutting mode than with a power of 100 W, and a desiccation zone was found below the vaporization zone (VZ). The VZ was thicker with a high contact pressure than with a low contact pressure. This VZ was deeper than the tissue defect and heat-affected zone obtained using a rollerball electrode or cutting loop electrode in the 45 W coagulation mode. CONCLUSION: Although caution is required because the VZ can become too deep with excessive pressure, the rollerball electrode seems to be safer and more useful than the cutting loop electrode for resection of flat or small papillary bladder tumors.

Animals↗
PubMed2001

[A case of loiasis].

Loiasis is quite common in the endemic regions of Central and West Africa. But only three cases were reported in Japan. This is a report of a 28 year old male from Gabon infected with Loa loa with eye symptoms as the chief complaint. For the first time in Japan he was treated with Ivermectin (IVM) which is recently attracting attention as the drug for filariasis world wide. IVM therapy was effective, and decreased the counts of microfilarias in the patient's blood. No adverse effect was seen in this patient. This case suggested that IVM is an useful drug for loiasis, and further study is warranted.

Adult↗
PubMed2001

Dynamic computer tomography is useful in the differential diagnosis of juxtaglomerular cell tumor and renal cell carcinoma.

We compared dynamic computer tomographic CT images of 3 cases of juxtaglomerular (JG) cell tumor with those of 8 cases of renal cell carcinoma (RCC). The JG cell tumor was visualized as a low- to high-density area in case 1, a low-density area in case 2, and a low- to iso-density area in case 3 before contrast enhancement. None of the JG cell tumors were stained during the early phase (1 min), but all were stained moderately during the late phase (5 min) after contrast enhancement. Although all cases of RCC were visualized as a low- to iso-density area before contrast enhancement, they were intensely stained during the early phase with significant washout during the late phase. The present results suggest that the dynamic CT scan is useful in the differential diagnosis of the JG cell tumor and RCC.

Adenocarcinoma↗
PubMed2001

[Development of new hydrophilic catheter kit for self-catheterization: study in pediatric cases].

PURPOSE: To increase the management of self-catheterization in children of school age, a catheter kit consisting of hydrophilic catheter and a packet containing sterilized water was developed. We evaluated the lubricating characteristic and clinical efficacy of this new catheter kit. MATERIALS AND METHODS: The catheter kit used in the study was a pocket-size plastic container in which a polyurethane catheter coated with hydrophilic polymer and a packet containing sterilized water were packed in combination. The lubricating characteristic of catheter was assessed by the measurement of friction value. For clinical assessment, male children aged over 6 years old who were doing self-catheterization at 17 medical institutions nationwide were selected as the subjects. The 32 children who had given informed consent (mean age: 11.6 years old) were asked to use the catheter kit continuously for 1 week. The results were investigated by a questionnaire survey in which the assessment before and after the use was expressed in scores. At the same time, urinalysis and urine culture were examined. RESULTS: The friction value of hydrophilic catheter was equivalent to or less than that observed by applying a lubricant to the conventional catheter. The comparison of conventional catheter with the kit indicated significantly higher scores (assessment in 5 grades expressed in scores) for the portability and operability of the kit. Though there was no significant difference in the ease of insertion between the two catheters, there were several comments that the kit got stuck in the urethra when it was withdrawn. The global assessment gave a significantly higher score to the kit and 30 (94%) of the 32 children wanted to use the kit continuously. No increase in hematuria which caused a clinical problem or no new apparent urinary tract infection occurred after the use of the kit. CONCLUSIONS: Compared with the conventional catheter, the hydrophilic catheter kit highly satisfied a large number of children at the time of self-catheterization. Depending on the condition of children, the kit is considered useful for continued self-catheterization for a long term.

Child↗
PubMed2001

Evaluation of the AMPLICOR CMV, COBAS AMPLICOR CMV monitor and antigenemia assay for cytomegalovirus disease.

The AMPLICOR CMV (qualitative DNA assay by PCR), COBAS AMPLICOR CMV Monitor (quantitative DNA assay by PCR), and antigenemia assay were tested for their ability to diagnose cytomegalovirus (CMV) infection in 115 immunocompromised patients. The AMPLICOR qualitative assay and the antigenemia assay were positive for all nine patients with a clinical diagnosis of CMV disease. The AMPLICOR quantitative assay was negative for one of the nine patients. In 106 patients without CMV disease, the AMPLICOR qualitative test was positive in 22, the quantitative test was positive in 23, and the antigenemia test was positive in 55 patients. The AMPLICOR qualitative and quantitative assays had specificities of 79% and 78% in patients without CMV disease, while that of the antigenemia assay was 48%. Diagnostic efficiencies were 79% for the AMPLICOR qualitative assay, 69% for the AMPLICOR quantitative assay, and 48% for the antigenemia assay. All three tests yielded positive results before, or at the same time as, the onset of CMV disease in most cases, which suggests they can be used to predict disease before the onset of symptoms. During antiviral treatment, test results tended to decrease quantitatively and finally became negative; negative results were followed by remission of symptoms. This suggests that the AMPLICOR quantitative assay and the antigenemia assay could be useful for monitoring therapeutic efficacy. The AMPLICOR qualitative and quantitative assays, as well as the antigenemia assay were considered effective for all of the following: diagnosing CMV disease, predicting the onset of disease, and evaluating the effectiveness of antiviral chemotherapy. The antigenemia assay was at times difficult to perform in the case of severely neutropenic patients, whereas the AMPLICOR assays could be used in such cases.

Antigens, Viral↗
PubMed2001

Sonographic characteristics of the urinary tract in healthy neonates.

PURPOSE: In infancy it has been reported that intravesical pressure is generally higher in males than in females. We investigated whether there are significant differences in the sonographic characteristics of the urinary tract in male and female neonates. MATERIALS AND METHODS: The study comprised 280 consecutive full-term newborns, including 146 males and 134 females. Kidneys were assessed for hydronephrosis and graded according to Society for Fetal Urology guidelines. Kidney measurements included maximum longitudinal length and largest longitudinal area. Bladder measurements included bladder dimensions and wall thickness. Bladder wall thickness was measured only in neonates with an estimated bladder volume of greater than 10 ml. RESULTS: Of the 280 neonates 114 had mild renal pelvic dilatation in at least 1 kidney and the incidence in males was significantly higher than in females (53% versus 27%). Kidney longitudinal length and largest area were significantly greater in males on each side. Mean bladder volume was essentially equal in the 169 male and female neonates with an estimated bladder volume of greater than 10 ml. but mean bladder wall thickness was significantly greater in males than in females (1.63 versus 1.38 mm.). CONCLUSIONS: Our study shows that there are marked differences in sonographic findings in male and female neonates in regard to renal pelvic dilatation, renal size and bladder wall thickness. These differences should be considered when sonography is done for screening for urinary tract anomalies in newborns.

Female↗
PubMed2001

The influence of sex hormones on renal osteopontin expression and urinary constituents in experimental urolithiasis.

PURPOSE: To our knowledge the influence of sex hormones on urinary stone formation remains undetermined. We investigated the effect of castration on urinary lithogenic factors and renal osteopontin expression in rats previously treated with ethylene glycol. MATERIALS AND METHODS: Sprague-Dawley rats were divided normal males, castrated males, males with 2 weeks of 0.75% ethylene glycol treatment, castrated males with 2 weeks of 0.75% ethylene glycol treatment, normal females, castrated females, females with 2 weeks of 0.75% ethylene glycol treatment and castrated females with 2 weeks of 0.75% ethylene glycol treatment. We analyzed 24-hour urine samples for urinary constituents, such as calcium, oxalate, citrate, uric acid, phosphate, magnesium, sodium, potassium and creatinine. The kidneys were examined for osteopontin expression by Northern blot analysis and for crystal deposition by histological examination. RESULTS: In intact male rats calcium and citrate excretion decreased and oxalate excretion increased significantly after ethylene glycol treatment. Castrated male rats with ethylene glycol had greater calcium and less oxalate excretion than male intact rats with ethylene glycol. In intact female rats uric acid excretion decreased and only calcium excretion increased significantly after ethylene glycol treatment. Castrated female rats with ethylene glycol excreted significantly more oxalate and less calcium than intact female rats with ethylene glycol. Renal osteopontin expression was the same in male intact and castrated rats, and in female intact and castrated rats. In males with ethylene glycol expression was stronger in castrated than in intact rats. In females with ethylene glycol expression was weaker in castrated than in intact rats. No crystal deposits were found in the kidneys in any group. CONCLUSIONS: Testosterone appears to promote stone formation by suppressing osteopontin expression in the kidneys and increasing urinary oxalate excretion. Estrogen appears to inhibit stone formation by increasing osteopontin expression in the kidneys and decreasing urinary oxalate excretion.

Animals↗
PubMed2001

Possibility of false-positive detection for sporozoites in mosquitos (Diptera: Culicidae) by nested polymerase chain reaction using Plasmodium yoelii genomic DNA.

Anopheles stephensi Liston and An. saperoi Bohart and Ingram infected with the rodent malaria parasite Plasmodium yoelii nigeriense. They were examined 12 and 19 days after blood feeding for sporozoites in head with anterior thorax (HT) and oocysts in abdomen with posterior thorax (AB) by light microscopy and by the nested polymerase chain reaction (nested PCR-based on the amplification of the sequences of the small subunit ribosomal RNA gene). The detection rate of parasite DNA by nested PCR in HT samples 12 days after blood feeding was similar to that by microscopic method. However, in HT samples 19 days after blood feeding, the rate by the PCR method was higher than that by the microscopic method. The incidence of sporozoites in salivary glands of infected mosquitos for 12 days after blood sucking was examined by the PCR method. Parasite DNA in HT of Aedes albopictus Skuse (a non vector for the rodent malaria) as well as An. stephensi and An. saperoi was detected for up to 4 days after feeding on mouse with the rodent malaria parasites. The results indicate that when the PCR method is used for detection of sporozoites of human malaria in mosquitos collected in the field, there are possibilities of including false-positive data for mosquitos that have just or recently fed on human blood infected with malaria (erythrocytic form).

Aedes↗
PubMed2000

Role of anti-A/B antibody titers in results of ABO-incompatible kidney transplantation.

BACKGROUND: Our previous studies showed that the incidence of humoral rejection was extremely high in ABO-incompatible living kidney transplantation. This result suggests that anti-A/B antibody titers directly influence the graft survival of ABO-incompatible kidney transplantation. In this study, we examined the impact of preoperative anti-A/B antibody titers on the results of ABO-incompatible living kidney transplantation. METHODS: Sixty-seven patients underwent ABO-incompatible living kidney transplantation at our institution between January 1989 and December 1995. The mean age was 34.9 years with 38 males and 29 females. Sixty-one of the 67 recipients were included in an analysis of the impact of anti-A/B antibody titer in long-term graft survival. The remaining six patients were excluded because of death with a functioning graft (three patients) and withdrawal of immunosuppression due to nonimmunological reasons (three patients) within 1 year after renal transplantation. RESULTS: The graft survival rate for the level of less than 1:16 in maximum IgG antibody before transplantation (n=21) at 1, 5, and 8 years was 81.0, 66.8, and 66.8%, respectively. The corresponding values for the level of 1:32-1:64 (n=33) and higher than 1:128 (n=7) were 93.9, 90.5, and 79.7%, and 42.9, 28.6, and 28.6%, respectively (log-rank test, P=0.0007). There was no significant association between maximum anti-A/B IgM titers, minimum anti-A/B IgM titers, minimum anti-A/B IgG titers, and graft survival. CONCLUSIONS: Preoperative maximum anti-A/B IgG titers correlated with the long-term graft survival in ABO-incompatible living kidney transplantation. Thus, preoperative maximum levels of anti-A/B IgG titers are one of the good predictors of the results of ABO-incompatible living kidney transplantation.

ABO Blood-Group System↗
PubMed2000

Anti-AB titer changes in patients with ABO incompatibility after living related kidney transplantations: survey of 101 cases to determine whether splenectomies are necessary for successful transplantation.

BACKGROUND: A shortage of organ donors for transplantation has become a serious problem throughout the world. To overcome this problem, transplantations across ABO blood barriers have been performed with some success. In general, however, the graft survival rate for transplantation with ABO incompatibility is lower than that of transplantation with ABO compatibility. Unfortunately, the mechanism by which isohemagglutinins might injure an ABO-incompatible graft remains uncertain. Here, the pre- and posttransplantation anti-AB titers in patients who received transplants from ABO-incompatible living donors are reviewed and the pathological findings are compared. METHODS: One hundred and one patients underwent ABO-incompatible living related kidney transplantation (i-LKT) between January 1989 and October 1999 at our hospital. Plasmapheresis and immunoadsorption were performed in all of the i-LKT patients before the transplantation to remove anti-AB antibodies. A splenectomy was also performed during the operation, followed by the local irradiation of the graft with a dose of 150 rad. The anti-AB titers and pathological findings for 93 i-LKT patients, excluding 8 patients who died, were then examined. RESULTS: Immediately after the i-LKT, the anti-AB titer dropped rapidly to below 1:4 in all 93 cases. Seventy of patients (70/93, 75%) showed no elevation in their anti-AB titer during their follow-up. However, the remaining 23 patients (23/93, 25%) showed a significant elevation of their anti-AB titer to over 1:16. Sixteen of these patients (16/93, 17%) exhibited an anti-AB titer of over 1:32. Out of these 16 patients, 11 patients (11/16, 69%) lost their grafts. The anti-AB titer in the remaining five patients (5/16, 31%) spontaneously decreased without any special treatment. Seven patients (7/93, 8%) exhibited an elevated titer of 1:16. Out of these patients, only one patient (1/7, 14%) lost his graft. The elevated titers in the remaining six patients (6/7, 86%) eventually decreased. The graft function improved in patients whose elevated anti-AB titers eventually decreased. Control patients (ABO-compatible kidney transplant patients) showed a normal elevation of their titer values compared with preoperative titers. Pathological findings showed severe humoral rejections in all cases with high anti-AB titers that lost grafts. Humoral rejection was also detected in most of the patients whose anti-AB titer was elevated to over 1:16 after the transplantation, but excellent renal function was resumed once the titers decreased to below 1:4. CONCLUSIONS: In 23 out of 93 i-LKT patients (25%), the anti-AB titers were significantly elevated after the splenectomy. In view of other reports of i-LKT without splenectomy, we feel that a splenectomy in i-LKT patients might be unnecessary. Pathological evidence suggests that the decrease in the anti-AB titer after transplantation might be the net result of plasmapheresis before the operation and the adsorption of antibodies to the endothelium of the transplanted organ after the operation, neither of which is influenced by a splenectomy.

ABO Blood-Group System↗
PubMed2000

Sialyl Lewis(x) (CD15s) monitoring as a means to select antirejection therapy in patients with rejection after renal transplantation: CD15s monitoring for treatment and diagnosis in patients with acute rejection after renal transplantation.

BACKGROUND: Sialyl Lewis(x) (CD15s), which is known to serve as a ligand for the cell adhesion molecules E-selectin and P-selectin, is expressed on peripheral lymphocytes in renal transplant patients with rejection. In this study, we examined whether CD15s monitoring could differentiate the patients with rejection in whom steroids were effective from those in whom steroids were not effective. METHODS: To investigate CD15s expression on peripheral lymphocytes, flow cytometry was performed before and after steroid pulse therapy in 20 recipients with rejection after renal transplantation, including 5 recipients resistant to steroid therapy. We also compared CD15s expression with pathological findings before and after steroid pulse therapy. RESULTS: CD15s expression was stronger before steroid pulse therapy in the 5 patients resistant to steroids than in the 15 patients responsive to steroid treatment. In addition, CD15s expression remained high without any pathological improvement in the 5 patients resistant to steroids after steroid treatment, although CD15s recovered to normal levels with remarkable improvement of pathological findings in the other 15 patients. Five patients in whom steroids were not effective, had full recovery of serum creatinine levels as well as CD15s expression after muromonab (OKT3) therapy. CONCLUSIONS: CD15s monitoring might help clinicians to select antirejection therapy.

Adult↗
PubMed2000

Early increased chemokine expression and production in murine allogeneic skin grafts is mediated by natural killer cells.

BACKGROUND: Increased expression of chemokine mRNA is observed in allogeneic but not syngeneic skin grafts 3-4 days after transplantation. The recipient cells mediating this early inflammatory response in allografts remain unidentified. METHODS: Isogeneic and allogeneic skin grafts were transplanted to euthymic and athymic nude mice. mRNA expression and protein production of macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, and the murine homolog of Gro(alpha), i.e. KC, from graft homogenates retrieved 3-4 days posttransplantation was tested by Northern blot hybridization and ELISA. To deplete NK cells, recipients were treated with antiasialo GM1 (ASGM1) antisera or with anti-NK1.1 mAb before transplantation. RESULTS: Expression of KC, MIP-1alpha, and MIP-1beta mRNA was equivalent in C57BL/6 allogeneic skin grafts and BALB/c isografts at day 2 posttransplant. At day 3 posttransplant, chemokine mRNA levels decreased in isografts but were maintained at high levels in the allografts. Increased early chemokine mRNA was also observed in C57BL/6, but not BALB/c++ grafts on BALB/c athymi(nu/nu) recipients. Treatment of allograft recipients with ASGM1 or with anti-NK1.1 antibody eliminated NK cells from the spleen and allograft infiltrating cell populations and decreased early chemokine mRNA levels in allografts 60-70%. Analyses of allograft homogenates indicated increased levels of KC, MIP-1alpha, and MIP-1beta protein at day 4 posttransplant that were decreased in recipients depleted of NK cells. Early chemokine mRNA levels were equivalent in isogeneic and semiallogeneic F1 grafts. CONCLUSIONS: Early chemokine mRNA expression and protein production in allogeneic skin grafts is amplified by recipient natural killer (NK) cells. These results indicate a novel function for infiltrating NK cells in mediating early increased intra-allograft chemokine production and inflammation during the initiation of acute rejection.

Animals↗
PubMed2000

Clinical utility of monitoring sialyl Lewis(X) (CD15S) antigen on peripheral lymphocytes for the diagnosis and treatment of rejection after renal transplantation.

BACKGROUND: In organ transplantation, the grafts must be carefully monitored, but it is often difficult to make a quick and accurate diagnosis of unusual changes. Extensive research has failed to identify a useful marker for rejection. We investigated the clinical utility of sialyl Lewis(X) (CD15s) monitoring in 17 renal transplant patients with acute rejection. METHODS: The expression of CD15s on peripheral lymphocytes was examined using flow cytometry in renal transplant recipients with rejection (n=17), without rejection (n=23), recipients infected with cytomegalovirus (n=7), recipients with other diseases (n=7), and healthy volunteers (n=18). CD15s expression was compared with histological findings, and was also examined before and after steroid pulse therapy to investigate the effects of steroids on CD15s antigen expression on the surface of the peripheral lymphocytes. RESULTS: CD15s was strongly expressed in all patients with rejection, but was not expressed in any of the patients without rejection or in any healthy volunteers. Histologically, cell infiltration into the rejected graft was moderate or severe in all patients with strong expression of CD15s. In contrast, no or only mild infiltration was observed in patients with weak expression of CD15s. In addition, 14 of 17 patients (14/17, 82%) with strong CD15s expression improved upon administration of steroid pulse therapy, although there was no benefit from steroids in any of the patients with weak expression of CD15s. CONCLUSIONS: The CD15s antigen is expressed strongly on the peripheral lymphocytes at the time of rejection. It is interesting that the efficacy of steroid therapy in the patients with elevated creatinine could be predicted by CD15s expression on the peripheral lymphocytes before graft biopsy. There have been only few reports showing the relationship between CD markers and the efficacy of the treatment in patients with elevated creatinine. We report that the detection of CD15s on the peripheral lymphocytes by flow cytometry was an easy, helpful, and noninvasive means for the diagnosis and treatment of patients with elevated creatinine after renal transplantation.

Adult↗
PubMed2000

ABO-incompatible pediatric kidney transplantation in a single-center trial.

We have performed ten pediatric kidney transplantations from living-related ABO-incompatible donors. All patients underwent preoperative plasmapheresis with or without immunoadsorption to reduce isoagglutinin. Primary immunosuppression consisted of methyl-prednisolone, cyclosporin or tacrolimus, azathioprine, anti-lymphocyte globulin, and/or deoxyspergualin. At transplantation splenectomy was simultaneously performed in all patients. Median follow-up is 65 months (range 4-95 months). The patient and graft survival rates are 100% to date. Post-transplantation isoagglutinin titers did not increase more than 1:32, except for 1 patient, without uncontrollable vascular rejection episodes. Despite the heavy immunosuppressive regimen, cytomegalovirus infection occurred in only three patients, who were successfully treated with ganciclovir and cytomegalovirus high-titer gamma globulin. Our small series clearly shows that the preoperative reduction of isoagglutinin, splenectomy, and strict immunosuppressive therapy lead to successful long-term results in children.

ABO Blood-Group System↗