[Genetic susceptibility to drug-induced liver injury]

Drug-induced liver injury (DILI) risk prediction, diagnosis establishment, clinical management, and all other aspects are facing great challenges. Although the current understanding of its pathogenesis is still incomplete, research over the past 20 years has shown that genetic susceptibility may play an important role in the occurrence and development of DILI. In recent years, pharmacogenomics studies have further revealed the association between human leukocyte antigen (HLA) genes, some non-HLA genes, and hepatotoxicity from certain drugs. However, due to the lack of well-designed, prospective, large-sample cohort validation and low positive predictive values, there may still be some way to go before the current results can be truly translated into clinical practice for precise prediction and prevention of DILI risk.

[Simulation of dose distribution in bone medium of 125I photon emitting source with Monte Carlo method]

OBJECTIVE

To present a theoretical analysis of how the presence of bone in interstitial brachytherapy affects dose rate distributions with MCNP4C Monte Carlo code and to prepare for the next clinical study on the dose distribution of interstitial brachytherapy in head and neck neoplasm.

METHODS

Type 6711,¹²⁵I brachytherapy source was simulated with MCNP4C Monte Carlo code whose cross section library was DLC-200. The dose distribution along the transverse axis in water and dose constant were compared with the American Association of Physicists in Medicine (AAPM) TG43UI update dosimetry formalism and current literature. The validated computer code was then applied to simple homogeneous bone tissue model to determine the affected different bone tissue had on dose distribution from ¹²⁵I interstitial implant.

RESULTS

¹²⁵I brachytherapy source simulated with MCNP4C Monte Carlo code met the requirements of TG43UI report. Dose rate constant, 0.977 78 cGy/(h×U), was in agreement within 1.32% compared with the recommended value of TG43UI. There was a good agreement between TG43UI about the dosimetric parameters at distances of 1 to 10 cm along the transverse axis of the ¹²⁵I source established by MCNP4C and current published data. And the dose distribution of ¹²⁵I photon emitting source in different bone tissue was calculated. Dose-deposition capacity of photons was in decreasing order: cortical bone, spongy bone, cartilage, yellow bone marrow, red bone marrow in the same medium depth. Photons deposited significantly in traversal axis among the phantom material of cortical bone and sponge bone relevant to the dose to water. In the medium depth of 0.01 cm, 0.1 cm, and 1 cm, the dose in the cortical bone was 12.90 times, 9.72 times, and 0.30 times of water respectively.

CONCLUSION

This study build a ¹²⁵I source model with MCNP4C Monte Carlo code, which is validated, and could be used in subsequent study. Dose distribution of photons in different bone medium is not the same as water, and its main energy deposits in bone medium surface, so we should consider the effect of bone medium when we design the target area adjacent to the bone tissue in ¹²⁵I sources implantation plan.

Pharmacogenetic aspects of the use of tacrolimus in renal transplantation: recent developments and ethnic considerations

INTRODUCTION

Tacrolimus (Tac) is effective in preventing acute rejection but has considerable toxicity and inter-individual variability in pharmacokinetics and pharmacodynamics. Part of this is explained by polymorphisms in genes encoding Tac-metabolizing enzymes and transporters. A better understanding of Tac pharmacokinetics and pharmacodynamics may help to minimize different outcomes amongst transplant recipients by personalizing immunosuppression.

AREAS COVERED

The pharmacogenetic contribution of Tac metabolism will be examined, with a focus on recent discoveries, new developments and ethnic considerations.

EXPERT OPINION

The strongest and most consistent association in pharmacogenetics is between the CYP3A5 genotype and Tac dose requirement, with CYP3A5 expressers having a ~ 40-50% higher dose requirement compared to non-expressers. Two recent randomized-controlled clinical trials using CYP3A5 genotype, however, did not show a decrease in acute rejections nor reduced toxicity. CYP3A4*22, CYP3A4*26, and POR*28 are also associated with Tac dose requirements and may be included to provide the expected improvement of Tac therapy. Studies focusing on the intracellular drug concentrations and on calcineurin inhibitor-induced nephrotoxicity also seem promising. For all studies, however, the ethnic prevalence of genotypes should be taken into account, as this may significantly impact the effect of pre-emptive genotyping.

Empty capsids in column-purified recombinant adenovirus preparations

Empty capsids from adenovirus, that is, virus particles lacking DNA, are well documented in the published literature. They can be separated from complete virus by CsCl density gradient centrifugation. Here we characterize the presence of empty capsids in recombinant adenovirus preparations purified by column chromatography. The initial purified recombinant adenovirus containing the p53 tumor suppressor gene was produced from 293 cells grown on microcarriers and purified by passage through DEAE-Fractogel and gel-filtration chromatography. Further sequential purification of the column-purified virus by CsCl and glycerol density gradient centrifugations yielded isolated complete virus and empty capsids. The empty capsids were essentially noninfectious and free of DNA. Analysis of empty capsids by SDS-PAGE or RP-HPLC showed the presence of only three major components: hexon, IIIa, and a 31K band. This last protein was identified as the precursor to protein VIII (pVIII) by mass spectrometric analysis. No pVIII was detected from the purified complete virus. Analysis by electron microscopy of the empty capsids showed particles with small defects. The amount of pVIII was used to determine the level of empty capsid contamination. First, the purified empty capsids were used to quantify the relation of pVIII to empty capsid particle concentration (as estimated by either light scattering or hexon content). They were then used as a standard to establish the empty capsid concentration of various recombinant adenovirus preparations. Preliminary research showed changes in empty capsid concentration with variations in the infection conditions. While virus purification on anion-exchange or gel-filtration chromatography has little effect on empty capsid contamination, other chromatographic steps can substantially reduce the final concentration of empty capsids in column-purified adenovirus preparations.

Extraction and characterization of adenovirus proteins from sodium dodecylsulfate polyacrylamide gel electrophoresis by matrix-assisted laser desorption/ionization mass spectrometry

A new methodology for the extraction and characterization of proteins from Coomassie-stained sodium dodecylsulfate polyacrylamide gel electrophoresis using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been described. The utility of this methodology was demonstrated in the characterization of adenovirus proteins. The key steps in the extraction and destaining process involve washing the excised band with a combination of solvents that include 10% acetic acid, acetonitrile, methanol, and formic acid:water:isopropanol mixture. By using this procedure, we determined adenovirus proteins with molecular weights ranging from 10,000 to 110,000 Da by MALDI-MS, obtaining a detection limit of approximately 6 pmol. Parallel experiments were successfully carried out to analyze adenovirus proteins from Cu-stained gels. It was observed that increase in laser intensity resulted in significant improvements in the quality of MALDI mass spectra for the analysis of inefficiently destained proteins from Cu-stained gels.

Mitochondrial DNA influences radiation sensitivity and induction of apoptosis in human fibroblasts

BACKGROUND

We aimed to assess the role of mitochondrial DNA (mtDNA) in ionizing irradiation.

MATERIAL AND METHODS

We examined three human fibroblast cell lines either lacking mtDNA (rho 0 cell), carrying mutant mtDNA (syn cell) or normal mtDNA (rho + cell). Cell survival curves were generated with colony formation and dye exclusion tests. Cell cycle analysis and apoptosis assay were performed by flow cytometry.

RESULTS

The rho 0 cell line showed a stronger resistance to irradiation than the other two cell lines when assessed by the colony formation assay. In the dye exclusion test, the rho 0 cells revealed a superior cell viability among the cell lines after 5 and 8 Gy irradiation. The rho 0 cells underwent apoptosis at lower rates than the other two cell lines after 2, 5 and 8 Gy irradiation, and showed no alterations in the cell cycle distribution among them.

CONCLUSION

mtDNA plays an important role in radiation sensitivity and induction of apoptosis.

Differences in the biological effects of in vitro irradiation by 65 MeV protons and 137cesium gamma-rays

Using the irradiation system constructed for research in radiation biology, we have investigated the differences in the biological effects of in vitro irradiation by 65 MeV protons and by 137Cs gamma-rays. Survival curves were generated using V79 cells. The effects on biological parameters (SF2, RBE) of protons were greater than gamma-rays. Furthermore, 3H-thymidine incorporation in KOSC-3 cells, which display the p53 gene mutation, was inhibited by protons much more than by gamma-rays. On the other hand, in bleomycin-sensitive SCCKN cells, 3H-thymidine incorporation decreased more than in bleomycin-resistant SCCTF cells, however, both were inhibited by protons much more than by gamma-rays. In this study, the biological parameters and 3H-thymidine incorporation caused by 65 MeV protons were more severe than those caused by 137Cs gamma-rays.

5 Gy irradiation does not alter the expression level of WT1 (Wilms tumor gene) in K562 and ML1

Recently, Wilm's Tumor gene (WT1) has been identified as a predisposing indicator for the activity of leukemia. To know the influence of irradiation on the expression level of WT1, we examined changes in WT1 expression after 5 Gy of irradiation of the K562 and ML1 cell lines (lymphoblastic cell lines). 48 hours after irradiation we could not find any alteration in the expression of WT1 at the mRNA and protein levels. Therefore, our results indicate that 5 Gy of irradiation does not induce differentiation of the leukemia cells.

Mechanism of aneurysm formation after 830-nm diode-laser-assisted microarterial anastomosis

OBJECTIVE

The process of aneurysm formation after laser welding is described.

SUMMARY BACKGROUND DATA

The mechanism of aneurysm formation after laser-assisted microarterial anastomosis is presently unclear.

METHODS

A series of 830-nm diode-laser-assisted longitudinal aortorrhophy with a condition of 400 to 500 J/mm2 for 1 cm length of anastomosis versus conventional manual anastomoses were performed in 90 Wistar rats. To compare this technique with normal media process, a histologic examination of aneurysm formation was conducted.

RESULTS AND CONCLUSIONS

The results show that there are two important factors that cause aneurysm formation after laser-assisted anastomosis: 1) the vessel wall is damaged by laser heating; 2) proliferation of collagen fiber at the adventitia is absent during media reconstruction.

Effect of thoracic irradiation on hepatocyte growth factor in rats lung and in bronchoalveolar lavage fluid of patients with thoracic malignancies

This study aimed to examine the physiological role of hepatocyte growth factor (HGF) after thoracic irradiation. We analysed the changes of HGF protein levels in rat lung following 12 Gy of whole thoracic irradiation. Bronchoalveolar lavage fluid (BALF) was then collected from 11 patients (10 lung cancer and one oesophageal cancer) after completion of radiation therapy. One month after irradiation, the HGF protein level in the lungs of irradiated rats decreased (p<0.05), followed by a remarkable elevation in HGF protein levels 2 (p<0.05) and 3 months (nonsignificant) after irradiation accompanied by the clinical appearance of radiation pneumonitis. Finally, HGF protein levels in the lung returned to their original level 6 months after thoracic irradiation. In humans, HGF protein levels in the BALF in the limited irradiated area were lower than those obtained from unirradiated areas (p<0.05). In conclusion, hepatocyte growth factor production is transiently suppressed in the irradiated area after irradiation.

Heparin induces rapid and remarkable elevation of hepatocyte growth factor/scatter factor during trans arterial embolization of renal cell carcinoma

BACKGROUND

Our aim was to determined the change of serum hepatocyte growth factorl scatter factor (HGF) before and after transarterial embolization (TAE) for renal cell carcinoma (RCC).

MATERIALS AND METHODS

We examined serum HGF levels in two patients.

RESULTS

Serum HGF levels rapidly increased to six-fold higher levels immediately after heparin-injection even before embolization. Serum HGF then decreased to below 1.0 ng/ml at 6 hours after the procedure. The second peak (a two-fold increase) appeared 1-3 days after TACE. The first increase may have been due to the injection of heparin which releases HGF from the cell-surface and extracellular matrix. HGF is a pleiotropic cytokine which has a potential to enhance cell motility and angiogenesis related to tumor progression and the first larger elevation of serum HGF is enough to make a physiological effects.

CONCLUSION

Therefore, we should remind the physiological influence of heparin injection not only to prevent of clotting.

HDR and MDR intracavitary treatment for carcinoma of the uterine cervix. A prospective randomized study

AIM

Treatment of carcinoma of the uterine cervix by remote afterloading brachytherapy has been accompanied with new isotopes having dose rates different from the classical low-dose rate (LDR) radium source. The dose rate conversion factor from LDR to high-dose rate (HDR) found to be around 0.54 in most studies. As regards medium-dose rate (MDR) brachytherapy, the published data are very few and the experience is still short. In this study the experience of Osaka University Hospital with micro-HDR-Selectron and Selectron-MDR, as a preliminary report of the clinical trial, is presented.

PATIENTS AND METHOD

From August 1991 through April 1993, a total of 45 patients with carcinoma of the uterine cervix were randomly allocated to either microSelectron-HDR or Selectron-MDR at the Osaka University Hospital. As regards HDR, dose to point A was adjusted to 32 Gy (for stages I and II). 30 Gy/4 fractions, and 22.5 Gy/3 fractions, for stages III, and IV, respectively. The corresponding values in case of MDR were 35.6, 34 Gy/4 fractions, and 25.5 Gy/3 fractions. External irradiation, according to the stage, was the same in the 2 groups. Nucletron Planning System (NPS) was used for pre-treatment dose calculation at point A, rectal and bladder wall. The dose rate at point A ranged from 24 to 75.6 cGy/min for the HDR group, while for the MDR group ranged among 174.8 to 229.6 cGy/h.

RESULTS

The 3-year survival and loco-regional control rates for both modalities were nearly equivalent (62% and 67% for HDR and 68% and 74% for MDR). The cumulative rectal and bladder complication rates were the same in both groups (29% at 3 years), with only 1 patient (MDR-group) developed grade 3 rectal and bladder complication. In this study, point A dose rate correction factor from LDR to HDR was 0.53 and 0.6 from LDR to MDR.

CONCLUSIONS

From the previous reports from Osaka University Medical School, as well as others, HDR was proposed as an alternative to LDR brachytherapy for treatment of carcinoma of the uterine cervix. In this report, Selectron-MDR was nearly equivalent to the microSelectron-HDR as regards survival and loco-regional control rates as well as radiation-induced complication. This is a preliminary report, and the study still needs larger number of patients, and longer follow-up period.

Lack of effect of hepatocyte growth factor on bone marrow suppression induced by total body irradiation in the rat

We examined the role of hepatocyte growth factor (HGF) on the bone marrow suppression by irradiation, by analyzing peripheral blood counts 2 weeks after 7 Gy of total body irradiation in rats. The rats underwent two weeks of continuous intraperitoneal human recombinant HGF injection (50 mg/day) from one day before irradiation using an Alzet osmotic pump. Red blood cell, white blood cell, and platelet counts did not increase with response to administration of HGF. Thus HGF does not show protection against myelosuppression caused by total body irradiation.

Comparison of radiobiological effective depths in 65-MeV modulated proton beams

To assess the achievement of uniformity of radiobiological effectiveness at different depths in the proton spread-out Bragg peak (SOBP), Chinese hamster ovary (CHO) cells were exposed to 65-MeV modulated proton beams at the Research Center for Nuclear Physics (RCNP) of Osaka University. We selected four different irradiation positions: 2 mm depth, corresponding to the entrance, and 10, 18 and 23 mm depths, corresponding to different positions in the SOBP. Cell survival curves were generated with the in vitro colony formation method and fitted to the linear-quadratic model. With 137Cs gamma-rays as the reference irradiation, the relative biological effectiveness (RBE) values for a surviving fraction (SF) level of 0.1 are 1.05, 1.10, 1.12 and 1.19 for depths of 2, 10, 18 and 23 mm respectively. A significant difference was found between the survival curves at 10 and 23 mm (P < 0.05), but not between 18 and 10 mm or between 18 and 23 mm. There was a significant dependence of RBE on depths in modulated proton beams at the 0.1 surviving fraction level (P < 0.05). Moreover, the rise of RBEs significantly depended on increasing SF level or decreased approximately in correspondence with irradiation dose (P = 0.0001). To maintain uniformity of radiobiological effectiveness for the target volume, careful attention should be paid to the influence of depth of beam and irradiation dose.

Effect of radiotherapy on serum level of interleukin 6 in patients with cervical carcinoma

To determine the inflammatory state of cervical cancer after radiotherapy, we examined serum interleukin 6 levels (sIL-6) and C-reactive protein (CRP) before and after radiation therapy in sixteen patients with cervical cancer. External radiation therapy did not cause changes in sIL-6 and CRP during the examined periods. On the other hand, brachytherapy caused transient elevation of sIL-6 on the day after treatment by 6.39 +/- 1.89 pg/ml to 13.41 +/- 2.34 pg/ml (p < 0.05) while CRP did not show any significant change. Therefore, brachytherapy would induce a small inflammatory reaction. However, we confirmed that radiotherapy is a less invasive treatment than surgery from the point of view of cytokine related inflammation.

C-reactive protein as an indicator of effect and of adverse reaction to transcatheter arterial embolization

Serum C-reactive protein (sCRP) levels were measured before and after angiography and transcatheter arterial embolization (TAE) in 25 patients (four angiography, 21 TAE for hepatocellular carcinoma) to examine the correlation of sCRP to patients' reaction to TAE and the efficacy of TAE. Four patients without TAE showed little elevation of sCRP. Twenty-one patients with TAE showed a significant increase in sCRP. Peak levels of sCRP in the patients who achieved partial response were higher than those of the no-change group after TAE (p = 0.005). Peak sCRP levels of patients who showed an adverse reaction to TAE were higher than those of patients with no adverse reaction (p = 0.02). Increased sCRP after TAE reflects not only the degree of untoward reaction but also the effectiveness of TAE. Therefore, measurement of sCRP may be a useful means to assess the effect of TAE.

Radiographic changes following radiotherapy in the patients with lung cancer. Is the irradiated area of the mediastinum in the simulation film a significant factor?

BACKGROUND

Radiation induced lung injury is an ominous adverse reaction in the management of thoracic disease by radiation therapy. Although the importance of the area of irradiated lung is well known, the irradiated area of mediastinum is little to be considered in the routine treatment.

PURPOSE

To evaluate the significance of the irradiated area of the mediastinum in the simulation film for radiation induced lung injury.

PATIENTS AND METHODS

A total of 208 patients with primary lung cancer treated with radiation therapy were analyzed for incidence of radiation induced lung injury. Lung injury was defined as the appearance of an abnormal shadow on the chest radiograph. CT images were used to differentiate recurrence or other conditions. Age, sex, irradiation dose, irradiated lung area, T and N factors of the tumor, irradiated mediastinum area, performance status of patients, location of irradiated fields and use of chemotherapy were analyzed with Cox's multivariate regression model.

RESULTS

The cumulative rate of radiation induced lung injury at 12 months was 85%. Significant factor of radiation induced lung injury was irradiated area of the mediastinum (p = 0.03). Irradiated area of the lung (p = 0.18, n.s.), total tumor dose (p = 0.1, n.s.), use of chemotherapy (p = 0.08, n.s.) and location of irradiated field (p = 0.08, n.s.) may also have an effect on radiation induced lung injury.

CONCLUSION

The irradiated area of the mediastinum is one of the significant factors in radiation induced lung injury.

Serum interleukin 6 as a predicator of the therapeutic effect and adverse reactions after transcatheter arterial embolization

To evaluate the value of serum interleukin 6 (sIL-6) for the prediction of therapeutic effect and adverse reaction after transcatheter arterial embolization (TAE), sIL-6 was measured before and after angiography or TAE in 18 patients (three after angiography and 15 after TAE for hepatocellular carcinoma). The three patients with only angiography showed no elevation of sIL-6, while a significant increase was observed after TAE in the 15 hepatocellular carcinoma patients. The sIL-6 levels of patients with a partial response to TAE were higher at 48-72 hours after the procedure than those of patients with no response (P = 0.045), and the sIL-6 levels of patients who showed adverse reactions were higher at 6-24 h than those of patients without adverse reactions (P = 0.019). sIL-6 level at 48-72 h after TAE reflects the efficacy of TAE, whereas the level at 6-24 h after TAE is related to the severity of adverse reactions. Therefore, sIL-6 may be a useful indicator for prediction of the therapeutic effect of TAE as well as adverse reactions.

High-dose-rate remote afterloading intestinal radiotherapy employing the template technique for recurrent cancer in the pelvic area

Between December 1991 and August 1992, five patients with recurrent cancer in the pelvic area (four gynecological cancers and one rectal cancer) were treated at Osaka University Hospital with a remote afterloading interstitial implantation employing the template technique. External irradiation (40 to 50 Gy) was performed in four cases one to four weeks before brachytherapy. Interstitial high-dose-rate brachytherapy (24 to 40 Gy/four to eight fractions/two to four days) was performed twice a day. Three of the five patients achieved complete local tumor control. The remaining two patients obtained symptom relief. There were no complications serious enough to need surgical treatment. Moreover, this procedure is well tolerated and therefore an effective modality for elderly and frail patients.

Role of total body irradiation as based on the comparison of preparation regimens for allogeneic bone marrow transplantation for acute leukemia in first complete remission

The role of total body irradiation (TBI) for allogeneic bone marrow transplantation (BMT) for acute leukemia in first complete remission was reevaluated in this study. From Japanese BMT Registry, data of 123 acute leukemia patients in first complete remission who underwent allogeneic bone marrow transplantation in 22 hospitals between 1988 and 1990 were available for the present comparative study of preparation regimens with or without total body irradiation. Two-year survivals were 77% and 51% in the TBI containing regimen group and in the non-TBI regimen group, respectively (p = 0.0010). Corresponding two-year relapse rates were 16% and 37%, respectively (p = 0.0197). Corresponding probabilities of developing interstitial pneumonitis were 21% and 24%, respectively (p = 0.8127). The analysis of causes of death indicated that non-TBI regimen increased the incidence of septicemia and lethal organ failures, such as liver, heart, lung and other multiple sites. It was emphasized that an additional role of total body irradiation was to disperse the treatment-related toxicity in allogeneic bone marrow transplantation for acute leukemia.

Temperal and spatial measurement of rf electric field in a magnetized plasma using an emissive probe

rf electric field in the ion cyclotron frequency range (10 kHz-1MHz) is measured directly in the plasma using an emissive probe operated in a novel manner.

Interaction of steroids with nucleic acids

17beta-Estradiol and testosterone bind to both native and denatured DNA, and to RNA and poly(A)-poly(U). Binding affinity depends on the conformation of nucleic acid. Lowering the electrolyte concentration and raising the temperature increase the binding of 17beta-estradiol to native DNA and decrease that to denatured DNA. In 0.01 M NaCl and at 37 degrees, more 17beta-estradiol is bound to native DNA than to denatured DNA. Higher binding of steroid to denatured DNA relative to native DNA at low temperature and high ionic strength is related to larger fraction of binding sites per unit nucleotide in denatured DNA. In addition to 17beta-estradiol and testosterone, 17alpha-estradiol, 17beta-estradiol-3-methyl ether and 19-nortestosterone also stabilize the structure of nucleic acids and poly(A)-poly(U) against thermal denaturation. The 17beta-estradiol induced elevation of the T-m of DNA is diminished by methanol or high NaCl concentration. These results indicate the involvement of hydrogen bonding and hydrophobic interactions between steroids and nucleic acids. The results of binding isotherms and optical studies suggest a conformational dependence of the binding of steroids to nucleic acids.