Safety and Efficacy of Hypofractionated Radiotherapy Combined with Tyrosine Kinase Inhibitors in Patients with Lung Metastases after Liver Transplantation for Hepatocellular Carcinoma

PURPOSE/OBJECTIVE(S)

We evaluated the safety and efficacy of hypofractionated radiotherapy (HFRT) combined with tyrosine kinase inhibitors (TKIs) in patients with pulmonary metastases after orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC).

MATERIALS/METHODS

Twenty-five patients with lung metastases after OLT for HCC who underwent HFRT using helical tomotherapy concomitantly with TKIs (sorafenib or lenvatinib) were retrospectively. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall survival (OS), local control rate (LCR), objective response rate (ORR), and treatment-related side effects.

RESULTS

The median follow-up time was 35.5 months, with a median interval from OLT to lung metastasis of 15.3 months. The median PFS and OS were 9.9 and 32.7 months, respectively. The 1-, 2-, and 3-year PFS and OS rates were 36.0%, 16.0%, and 12.0%, and 84.0%, 52.0%, and 20.0%, respectively. The LCR of pulmonary metastases at 1 year was 100%, whereas the two-year LCR was 76.9%. The 1- and 2- year ORRs were 95.2% and 69.2%, respectively, with no grade > 2 adverse events. Radiation pneumonitis was observed in 17 patients (68.0%). Grade 1 pneumonitis occurred in 15 patients (60.0%), and grade 2 pneumonitis occurred in 2 patients (8.0%).

CONCLUSION

The combination therapy of HFRT with TKIs is a feasible, safe, and promising approach in the treatment of pulmonary metastases for HCC after OLT.

Salvage Radiotherapy Improves Survival in Patients with Metastatic Liver Cancer after Immunotherapy Oligoprogression

PURPOSE/OBJECTIVE(S)

Immune checkpoint inhibitors (ICIs) have ameliorated the survival outcome of liver cancer, a majority of patients receiving ICIs have eventually developed progression. Local therapy, especially radiotherapy (RT), is increasingly being considered in the setting of oligoprogression to delay the need to change systemic therapy. The aim of this study was to evaluate the efficacy and safety of RT as a salvage treatment in patients with oligoprogression after ICIs.

MATERIALS/METHODS

This retrospective study was performed to evaluate the use of salvage radiotherapy in oligoprogressive metastatic liver cancer patients. Patients with metastatic liver cancer who had previous stability or response after ≥ 6 mo of ICIs were eligible if they developed progression of five of fewer metastases.

RESULTS

Overall, 178 patients treated between August 2018 and March 2022 were included. The patients were followed for a median of 17.2 months. The overall response rate (ORR) and disease control rate (DCR) were 38.2% and 57.8%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 6.5 (95% CI:5.116-7.884) and 17.3 (95% CI:11.166-23.434) months. In multivariate analysis, factors associated with OS included tumor size, tumor number, and radiated tumor site (intrahepatic vs. extrahepatic). The most frequent AEs were fatigue, decreased appetite, rash, fever, and nausea. The above-mentioned AEs were reversible and manageable.

CONCLUSION

Salvage radiotherapy has a potential activity and is tolerable for oligoprogression after ICIs with appropriate radiated tumor site and patient selection. A prospective randomized trial is ongoing to validate this finding (ChiCTR2200060664).

Stereotactic Body Radiotherapy Combined with Sintilimab in Patients with Recurrent or Oligometastatic Hepatocellular Carcinoma: A Phase II Clinical Trial

PURPOSE/OBJECTIVE(S)

The anti-tumor activity and tolerability of stereotactic body radiotherapy (SBRT) and PD-1 inhibitors have been illustrated in retrospective studies, but the results vary across a broad range. This study aimed to assess the clinical efficacy of SBRT combined with sintilimab in patients with recurrent or oligometastatic hepatocellular carcinoma (HCC).

MATERIALS/METHODS

This trial involved patients with recurrent or oligometastatic HCC intravenously treated with SBRT plus sintilimab every 3 weeks for 12 months or until disease progression. The primary endpoint was progression-free survival (PFS).

RESULTS

Twenty-five patients were enrolled from August 14, 2019, to August 23, 2021. The median treatment duration was 10.2 months. SBRT was delivered at a median dose of 54 in six fractions. The median follow-up time was 21.9 months, and 32 targeted lesions among 25 patients were evaluated for treatment response according to the Response Evaluation Criteria in Solid Tumors version 1.1. The median PFS was 19.7 months, with PFS rates of 68% and 45.3% at 12 and 24 months, respectively. The median overall survival (OS) was not reached, with OS rates of 91.5% and 83.2% at 12 and 24 months, respectively. The 1- and 2-year local control rate were 100% and 90.9%, respectively. The confirmed objective response rate and disease control rate was 96%, and 96%, respectively. Most adverse events were graded as 1 or 2, and grade 3 adverse events were observed in three patients.

CONCLUSION

SBRT plus sintilimab is an effective, well-tolerated treatment regimen for patients with recurrent or oligometastatic HCC.

Decadal decrease in Los Angeles methane emissions is much smaller than bottom-up estimates

Methane, a powerful greenhouse gas, has a short atmospheric lifetime ( ~ 12 years), so that emissions reductions will have a rapid impact on climate forcing. In megacities such as Los Angeles (LA), natural gas (NG) leakage is the primary atmospheric methane source. The magnitudes and trends of fugitive NG emissions are largely unknown and need to be quantified to verify compliance with emission reduction targets. Here we use atmospheric remote sensing data to show that, in contrast to the observed global increase in methane emissions, LA area emissions decreased during 2011-2020 at a mean rate of (-1.57 ± 0.41) %/yr. However, the NG utility calculations indicate a much larger negative emissions trend of -5.8 %/yr. The large difference between top-down and bottom-up trends reflects the uncertainties in estimating the achieved emissions reductions. Actions taken in LA can be a blueprint for COP28 and future efforts to reduce methane emissions.

Neoadjuvant chemoradiotherapy versus neoadjuvant chemotherapy followed by minimally invasive esophagectomy for locally advanced esophageal squamous cell carcinoma: a prospective multicenter randomized clinical trial

BACKGROUND

Neoadjuvant therapy is recommended for locally advanced esophageal cancer, but the optimal strategy remains unclear. We aimed to evaluate the safety and efficacy of neoadjuvant chemoradiotherapy (nCRT) versus neoadjuvant chemotherapy (nCT) followed by minimally invasive esophagectomy (MIE) for locally advanced esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

Eligible patients staged as cT3-4aN0-1M0 ESCC were randomly assigned (1 : 1) to the nCRT or nCT group stratified by age, cN stage, and centers. The chemotherapy, based on paclitaxel and cisplatin, was administered to both groups, while concurrent radiotherapy was added for the nCRT group; then MIE was carried out. The primary endpoint was 3-year overall survival. This study is registered with ClinicalTrials.gov (NCT03001596).

RESULTS

A total of 264 patients were eligible for the intention-to-treat analysis. By 30 November 2021, 121 deaths had occurred. The median follow-up was 43.9 months (interquartile range 36.6-49.3 months). The overall survival in the intention-to-treat population was comparable between the nCRT and nCT strategies [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.58-1.18; P = 0.28], with a 3-year survival rate of 64.1% (95% CI 56.4% to 72.9%) versus 54.9% (95% CI 47.0% to 64.2%), respectively. There were also no differences in progression-free survival (HR 0.83, 95% CI 0.59-1.16; P = 0.27) and recurrence-free survival (HR 1.07, 95% CI 0.71-1.60; P = 0.75), although the pathological complete response in the nCRT group (31/112, 27.7%) was significantly higher than that in the nCT group (3/104, 2.9%; P < 0.001). Besides, a trend of lower risk of recurrence was observed in the nCRT group (P = 0.063), while the recurrence pattern was similar (P = 0.802).

CONCLUSIONS

NCRT followed by MIE was not associated with significantly better overall survival than nCT among patients with cT3-4aN0-1M0 ESCC. The results underscore the pending issue of the best strategy of neoadjuvant therapy for locally advanced bulky ESCC.

Perfluorooctane sulfonate affects mouse oocyte maturation in vitro by promoting oxidative stress and apoptosis induced bymitochondrial dysfunction

Perfluorooctane sulphonate (PFOS), as a surfactant, is widely applied in the agricultural production activities and has become a potential menace to human health. The mechanism of its effect on the maturation of mammalian oocytes is unclear. This study explored the toxic effect of PFOS on mouse oocyte maturation in vitro. The results revealed that PFOS under a concentration of 600 μM could significantly reduce the polar body extrusion rate (PBE) of mouse oocytes and cause symmetrical cell division. Further experiments showed that PFOS resulted in the abnormal cytoskeleton of the oocytes, causing the abnormal spindles and misplaced chromosomes, as well as the impaired dynamics of actin. Moreover, PFOS exposure inhibited the process of oocyte meiosis, which reflected in the slower spindle migration and continuous activation of spindle assembly checkpoint (SAC), then ultimately increased the probability of aneuploidy. Most importantly, PFOS exposure reduced the quality of oocytes, specifically by disrupting the function of mitochondria, inducing cell oxidative stress, and triggering early apoptosis. Furthermore, the level of methylation of histones is additionally influenced. In summary, our findings showed that PFOS exposure interfered with the maturation of mouse oocytes through affecting cytoskeletal dynamics, meiotic progression, oocyte quality, and histone modifications.

Societal shifts due to COVID-19 reveal large-scale complexities and feedbacks between atmospheric chemistry and climate change

The COVID-19 global pandemic and associated government lockdowns dramatically altered human activity, providing a window into how changes in individual behavior, enacted en masse, impact atmospheric composition. The resulting reductions in anthropogenic activity represent an unprecedented event that yields a glimpse into a future where emissions to the atmosphere are reduced. Furthermore, the abrupt reduction in emissions during the lockdown periods led to clearly observable changes in atmospheric composition, which provide direct insight into feedbacks between the Earth system and human activity. While air pollutants and greenhouse gases share many common anthropogenic sources, there is a sharp difference in the response of their atmospheric concentrations to COVID-19 emissions changes, due in large part to their different lifetimes. Here, we discuss several key takeaways from modeling and observational studies. First, despite dramatic declines in mobility and associated vehicular emissions, the atmospheric growth rates of greenhouse gases were not slowed, in part due to decreased ocean uptake of CO2 and a likely increase in CH4 lifetime from reduced NO x emissions. Second, the response of O3 to decreased NO x emissions showed significant spatial and temporal variability, due to differing chemical regimes around the world. Finally, the overall response of atmospheric composition to emissions changes is heavily modulated by factors including carbon-cycle feedbacks to CH4 and CO2, background pollutant levels, the timing and location of emissions changes, and climate feedbacks on air quality, such as wildfires and the ozone climate penalty.

Perfluorodecanoic acid induces meiotic defects and deterioration of mice oocytes in vitro

Perfluorodecanoic acid (PFDA) is a member of the perfluoroalkyl substances, which are toxic to organic functions. Recently, it has been found in follicular fluid, seriously interfering with reproduction. Follicular fluid provides the oocyte with necessary resources during the process of oocytes maturation. However, the effects of PFDA on the oocyte need investigation. Our study evaluated the impacts of PFDA on the meiosis and development potential of mouse oocytes by exposing oocytes to PFDA in vitro at 350, 400, and 450 μM concentrations. The results showed that exposure to PFDA resulted in the first meiotic prophase arrest by obstructing the function of the maturation-promoting factor. It also induced the dysfunction of the spindle assembly checkpoint, expedited the progression of the first meiotic process, and increased the risk of aneuploidy. The oocytes treated with PFDA had a broken cytoskeleton which also contributed to meiotic maturation failure. Besides, PFDA exposure caused mitochondria defections, increased the reactive oxygen species level in oocytes, and consequently induced oocyte apoptosis. Moreover, PFDA produced epigenetic modifications in oocytes and increased the frequency of mature oocytes with declined development potential. In summary, our data indicated that PFDA disturbs the meiotic process and induces oocyte quality deterioration.

Fbf1 regulates mouse oocyte meiosis by influencing Plk1

Fas binding factor 1 (Fbf1) is one of the distal appendage proteins in the centriole, located at its distal and proximal ends. It influences the duplication and separation of centrosomes, thereby affecting the progression of the cell cycle during mitosis. However, the function of Fbf1 in meiosis has remained unclear. To explore the role of Fbf1 in the in vitro maturation of mouse oocyte, immunofluorescence staining was used to examine the Fbf1 location in the oocyte and their phenotype after protein deletion. Western blot was used to examine the protein abundance. This study showed that mouse oocytes express Fbf1 which locates at the spindle poles and around the microtubules. Through taxol and nocodazole treatment, and microinjection of siRNA, it was demonstrated that Fbf1 had an important role in the spindle assembly and chromosome separation during mouse oocyte meiosis In particular, microinjection of Fbf1-siRNA resulted in severe abnormalities in the spindle and chromosome arrangement, decreased aggregation of microtubules, disrupted the first oocyte meiosis, and the extrusion of the first polar body. Furthermore, in the Fbf1-siRNA group, there was reduced expression of Plk1 and its agglutination at the spindle poles, along with retarded chromosome segregation due to the activation of the spindle assembly checkpoint (SAC) component BubR1. These results indicate that Fbf1 may function in microtubule depolymerization and agglutination, control the microtubule dynamics, spindle assembly and chromosome arrangement and, thus, influence the mouse oocyte meiotic maturation.

CAFs secreted exosomes promote metastasis and chemotherapy resistance by enhancing cell stemness and epithelial-mesenchymal transition in colorectal cancer

BACKGROUND

Cancer associated fibroblasts (CAFs) are key stroma cells that play dominant roles in tumor progression. However, the CAFs-derived molecular determinants that regulate colorectal cancer (CRC) metastasis and chemoresistance have not been fully characterized.

METHODS

CAFs and NFs were obtained from fresh CRC and adjacent normal tissues. Exosomes were isolated from conditioned medium and serum of CRC patients using ultracentrifugation method and ExoQuick Exosome Precipitation Solution kit, and characterized by transmission electronic microscopy, nanosight and western blot. MicroRNA microarray was employed to identify differentially expressed miRNAs in exosomes secreted by CAFs or NFs. The internalization of exosomes, transfer of miR-92a-3p was observed by immunofluorescence. Boyden chamber migration and invasion, cell counting kit-8, flow cytometry, plate colony formation, sphere formation assays, tail vein injection and primary colon cancer liver metastasis assays were employed to explore the effect of NFs, CAFs and exosomes secreted by them on epithelial-mesenchymal transition, stemness, metastasis and chemotherapy resistance of CRC. Luciferase report assay, real-time qPCR, western blot, immunofluorescence, and immunohistochemistry staining were employed to explore the regulation of CRC metastasis and chemotherapy resistance by miR-92a-3p, FBXW7 and MOAP1.

RESULTS

CAFs promote the stemness, epithelial-mesenchymal transition (EMT), metastasis and chemotherapy resistance of CRC cells. Importantly, CAFs exert their roles by directly transferring exosomes to CRC cells, leading to a significant increase of miR-92a-3p level in CRC cells. Mechanically, increased expression of miR-92a-3p activates Wnt/β-catenin pathway and inhibits mitochondrial apoptosis by directly inhibiting FBXW7 and MOAP1, contributing to cell stemness, EMT, metastasis and 5-FU/L-OHP resistance in CRC. Clinically, miR-92a-3p expression is significantly increased in CRC tissues and negatively correlated with the levels of FBXW7 and MOAP1 in CRC specimens, and high expression of exosomal miR-92a-3p in serum was highly linked with metastasis and chemotherapy resistance in CRC patients.

CONCLUSIONS

CAFs secreted exosomes promote metastasis and chemotherapy resistance of CRC. Inhibiting exosomal miR-92a-3p provides an alternative modality for the prediction and treatment of metastasis and chemotherapy resistance in CRC.

FMNL2 destabilises COMMD10 to activate NF-κB pathway in invasion and metastasis of colorectal cancer

BACKGROUND

Diaphanous-related formins (DRFs), actin necleator, have been known to participate in the progression of cancer cells. We previously reported that FMNL2 (Formin-like2), a member of DRFs, was a positive regulator in colorectal cancer (CRC) metastasis, yet proteins and pathways required for the function of this pro-invasive DRFs remain to be identified.

METHODS

The relationship between FMNL2 and COMMD10 was examined using Co-IP, GST pull-down, immunofluorescence and in vitro ubiquitination assay. The in vitro and in vivo function of COMMD10 in CRC was evaluated using CCK-8 proliferation assay, plate colony formation, cell cycle, apoptosis and animal models. The inhibition of NF-κB signalling by COMMD10 was detected using dual-luciferase reporter assay and western blotting. Co-IP, GST pull-down and nuclear protein extraction assay were performed to evaluate the effect on p65 by COMMD10. Real-time PCR and western blotting were performed to detect expressions of FMNL2, COMMD10 and p65 in paired tissues.

RESULTS

FMNL2 targets COMMD10 for ubiquitin-mediated proteasome degradation in CRC cells. COMMD10 targets p65 NF-κB (nuclear factor-κB) subunit and reduces its nuclear translocation, thereby leading to the inactivation of NF-κB pathway and suppression of CRC invasion and metastasis. Inhibition of NF-κB signalling by COMMD10 is necessary for FMNL2-mediated CRC cell behaviours. Downregulation of COMMD10 predicts poor prognosis of CRC patients. The expressions of FMNL2, COMMD10 and p65 are highly linked in CRC tissues.

CONCLUSIONS

These data demonstrate that the FMNL2/COMMD10/p65 axis acts as a critical regulator in the maintenance of metastatic phenotypes and is strongly associated with negative clinical outcomes.

Detection of Cytomegalovirus (CMV) Infection in Wheezing Infants by Urine DNA and Serum IgG Testing

BACKGROUND The aim of this study was to investigate the involvement of CMV infection in wheezing infants and the association between CMV-DNA and immunoglobulins (Igs). MATERIAL AND METHODS A total of 243 wheezing infants and 3,000 parturients were enrolled in this study. The infants were randomly grouped to receive blood HCMV-DNA tests (n=46) or urine HCMV-DNA tests (n=197). Furthermore, all participants had serum CMV-specific IgM and IgG testing. Afterwards, 10 HCMV-IgG positive infants were randomly selected for simultaneous blood and urine HCMV-DNA tests, and 25 HCMV-IgG positive puerperants were randomly selected for urine HCMV-DNA tests. RESULTS The detection rate of urine HCMV-DNA was significantly higher than that of blood HCMV-DNA (67.5% vs. 13.0%, p<0.001). Fifteen (6.2%) and 190 (80.0%) infants showed positive CMV-specific IgM and IgG results (p<0.001), respectively. Among the 10 HCMV-IgG positive infants tested further, only two infants had positive HCMV-DNA blood tests, while all of the 10 infants had positive HCMV-DNA urine tests. However, HCMV-DNA was not detected in the urine of the 25 randomly selected parturients positive for HCMV-IgG. CONCLUSIONS CMV infection may be one of the causes of wheezing in infants; CMV infection can be detected by urine-HCMV-DNA and serum HCMV-IgG testing. Infants were more susceptible to CMV infection than parturients.

FBX8 is a metastasis suppressor downstream of miR-223 and targeting mTOR for degradation in colorectal carcinoma

F-box proteins are critical components of the SKP1-CUL1-F-box (SCF) E3 ubiquitin ligases and involved in the ubiquitin-dependent proteolytic pathway. Dysregulation of F-box protein-mediated proteolysis often leads to human malignancies. F-box only protein 8 (FBX8), a novel component of F-box proteins, is down-regulated in several tumors and closely correlates with tumor progression. However, little is known about its function, regulatory mechanisms and substrates in the progression of colorectal carcinoma (CRC). Combining microRNA (miRNA) assay, functional characterization, mechanistic studies with clinical validation, we identify FBX8 as a CRC metastasis suppressor downstream of miR-223, a metastasis promoting miRNA that is transcriptionally regulated by Myocyte enhancer factor (MEF2A). mTOR is a substrate of FBX8 for ubiquitin-mediated degradation and is required for FBX8 induced cell proliferation and invasion in CRC cells. FBX8 is down-regulated in human CRC tissues and correlates with MEF2A, miR-223 and mTOR expression levels. Notably, low FBX8 expression status in CRC tissues was a significant prognostic factor for poor overall survival of patients. These findings illustrate FBX8 as a metastasis suppressor that functions through mTOR signaling pathway and has significant prognostic power.

Preparation and identification of an antiserum against recombinant UL31 protein of pseudorabies virus

Pseudorabies virus (PRV) early protein UL31 is a homologue of herpes simplex virus 1 (HSV-1) UL31, which is a multifunctional protein important for HSV-1 infection. However, the precise roles of PRV UL31 in virus life cycle are still poorly understood. A relatively crucial tool for uncovering the function of UL31 is an antiserum that specifically detects UL31 in the PRV-infected cells. For this purpose, a recombinant UL31 protein consisting of N-terminal 27 aa of UL31 fused to EYFP and His-tag was expressed, purified and used for the preparation of antiserum in BALB/c mice. Our results show that Western blot analysis and immunofluorescence assay showed that this antiserum could specifically detect the purified recombinant UL31 as well as full-length UL31 in the PRV infected cells. These results demonstrate that the prepared antiserum could serve as a valuable tool for further studies of UL31 functions in PRV infection.

Retrieval and analysis of atmospheric XCO2 using ground-based spectral observation

Atmospheric CO2 column concentration (column-averaged dry air mole fractions of atmospheric carbon dioxide) data obtained by ground-based hyperspectral observation is an important source of data for the verification and improvement of the results of CO2 retrieval based on satellite hyperspectral observation. However, few studies have been conducted on atmospheric CO2 column concentration retrieval based on ground-based spectral hyperspectral observation in China. In the present study, we carried out the ground-based hyperspectral observation in Xilingol Grassland, Inner Mongolia of China by using an observation system which is consisted of an optical spectral analyzer, a sun tracker, and some other elements. The atmospheric CO2 column concentration was retrieved using the observed hyperspectral data. The effect of a wavelength shift of the observation spectra and the meteorological parameters on the retrieval precision of the atmospheric CO2 concentration was evaluated and analyzed. The results show that the mean value of atmospheric CO2 concentration was 390.9 microg x mL(-1) in the study area during the observing period from July to September. The shift of wavelength in the range between -0.012 and 0.042 nm will generally lead to 1 microg x mL(-1) deviation in the CO2 retrievals. This study also revealed that the spectral transmittance was sensitive to meteorological parameters in the wavelength range of 6 357-6 358, 6 360-6 361, and 6 363-6 364 cm(-1). By comparing the CO2 retrievals derived from the meteorological parameters observed in synchronous and non-synchronous time, respectively, with the spectral observation, it was showed that the concentration deviation caused by using the non-synchronously observed meteorological parameters is ranged from 0.11 to 4 microg x mL(-1). These results can be used as references for the further improvement of retrieving CO2 column concentration based on spectral observation.

Evidence for factors modulating radiation-induced G2-delay: potential application as radioprotectors

Manipulation of checkpoint response to DNA damage can be developed as a means for protecting astronauts from the adverse effects of unexpected, or background exposures to ionizing radiation. To achieve this goal reagents need to be developed that protect cells from radiation injury by prolonging checkpoint response, thus promoting repair. We present evidence for a low molecular weight substance excreted by cells that dramatically increases the duration of the G2-delay. This compound is termed G2-Arrest Modulating Activity (GAMA). A rat cell line (A1-5) generated by transforming rat embryo fibroblasts with a temperature sensitive form of p53 plus H-ras demonstrates a dramatic increase in radiation resistance after exposure to low LET radiation that is not associated with an increase in the efficiency of rejoining of DNA double strand breaks. Radioresistance in this cell line correlates with a dramatic increase in the duration of the G2 arrest that is modulated by a GAMA produced by actively growing cells. The properties of GAMA suggest that it is a low molecular weight heat-stable peptide. Further characterization of this substance and elucidation of its mechanism of action may allow the development of a biological response modifier with potential applications as a radioprotector. GAMA may be useful for protecting astronauts from radiation injury as preliminary evidence suggests that it is able to modulate the response of cells exposed to heavy ion radiation, similar to that encountered in outer space.

Assay of serum arylesterase activity by fitting to the reaction curve with an integrated rate equation

BACKGROUND

Conventional enzyme activities make use of the initial reaction rate at high substrate concentrations. Because this is not always practical, alternative enzyme assays have been sought.

METHODS

Reaction curve fitting with an integrated rate equation was investigated to assay serum arylesterase (ArE) activity using phenyl acetate (PA) and p-nitrophenol acetate (PNPA) as substrates. At a much lower initial concentration of substrate (S(0)), the simplified integrated rate equation for the ArE reaction was ln(S(0)/S(i))=(V(m)/K(m)+K(d))t(i). Treating S(0) as a parameter, the enzyme activity as V(m)/K(m) was estimated through nonlinear least square fitting to reaction curve, and the multiplication of V(m)/K(m) by K(m) produced V(m). Spontaneous hydrolysis of the substrate with a rate constant, K(d), served as the background for the estimation of V(m)/K(m).

RESULTS

Substrate concentration at 8% of K(m) was well suited for the estimation of V(m)/K(m). With either substrate, the V(m)/K(m) showed a close relation to the percentage of substrate consumed, and was not affected by common systematic errors. With either substrate, the between-run precision for V(m)/K(m) was 6% (n>7), V(m)/K(m) was proportional to the amount of ArE and closely correlated with its initial rate. The upper limit of linearity by this integrated method was much higher than the initial rate method, while the detection limit was comparable. By using either V(m)/K(m) or the initial rate, there was negligible interference with ArE activity assay from triglycerides, bilirubin, and hemoglobin.

CONCLUSIONS

These results indicate the feasibility of the integrated method for routine assay of serum enzyme activity.

Deficiency of human BRCA2 leads to impaired homologous recombination but maintains normal nonhomologous end joining

Carriers of BRCA2 germline mutations are at high risk to develop early-onset breast cancer. The underlying mechanisms of how BRCA2 inactivation predisposes to malignant transformation have not been established. Here, we provide direct functional evidence that human BRCA2 promotes homologous recombination (HR), which comprises one major pathway of DNA double-strand break repair. We found that up-regulated HR after transfection of wild-type (wt) BRCA2 into a human tumor line with mutant BRCA2 was linked to increased radioresistance. In addition, BRCA2-mediated enhancement of HR depended on the interaction with Rad51. In contrast to the tumor suppressor BRCA1, which is involved in multiple DNA repair pathways, BRCA2 status had no impact on the other principal double-strand break repair pathway, nonhomologous end joining. Thus, there exists a specific regulation of HR by BRCA2, which may function to maintain genomic integrity and suppress tumor development in proliferating cells.

The radioresistance to killing of A1-5 cells derives from activation of the Chk1 pathway

Checkpoints respond to DNA damage by arresting the cell cycle to provide time for facilitating repair. In mammalian cells, the G(2) checkpoint prevents the Cdc25C phosphatase from removing inhibitory phosphate groups from the mitosis-promoting kinase Cdc2. Both Chk1 and Chk2, the checkpoint kinases, can phosphorylate Cdc25C and inactivate its in vitro phosphatase activity. Therefore, both Chk1 and Chk2 are thought to regulate the activation of the G(2) checkpoint. Here we report that A1-5, a transformed rat embryo fibroblast cell line, shows much more radioresistance associated with a much stronger G(2) arrest response when compared with its counterpart, B4, although A1-5 and B4 cells have a similar capacity for nonhomologous end-joining DNA repair. These phenotypes of A1-5 cells are accompanied by a higher Chk1 expression and a higher phosphorylation of Cdc2. On the other hand, Chk2 expression increases slightly following radiation; however, it has no difference between A1-5 and B4 cells. Caffeine or UCN-01 abolishes the extreme radioresistance with the strong G(2) arrest and at the same time reduces the phosphorylation of Cdc2 in A1-5 cells. In addition, Chk1 but not Chk2 antisense oligonucleotide sensitizes A1-5 cells to radiation-induced killing and reduces the G(2) arrest of the cells. Taken together these results suggest that the Chk1/Cdc25C/Cdc2 pathway is the major player for the radioresistance with G(2) arrest in A1-5 cells.

Efficient rejoining of radiation-induced DNA double-strand breaks in vertebrate cells deficient in genes of the RAD52 epistasis group

Rejoining of ionizing radiation (IR) induced DNA DSBs usually follows biphasic kinetics with a fast (t(50): 5-30 min) component attributed to DNA-PK-dependent non-homologous endjoining (NHEJ) and a slow (t(50): 1-20 h), as of yet uncharacterized, component. To examine whether homologous recombination (HR) contributes to DNA DSB rejoining, a systematic genetic study was undertaken using the hyper-recombinogenic DT40 chicken cell line and a series of mutants defective in HR. We show that DT40 cells rejoin IR-induced DNA DSBs with half times of 13 min and 4.5 h and contributions by the fast (78%) and the slow (22%) components similar to those of other vertebrate cells with 1000-fold lower levels of HR. We also show that deletion of RAD51B, RAD52 and RAD54 leaves unchanged the rejoining half times and the contribution of the slow component, as does also a conditional knock out mutant of RAD51. A significant reduction (to 37%) in the contribution of the fast component is observed in Ku70(-/-) DT40 cells, but the slow component, operating with a half time of 18.4 h, is still able to rejoin the majority (63%) of DSBs. A double mutant Ku70(-/-)/RAD54(-/-) shows similar half times to Ku70(-/-) cells. Thus, variations in HR by several orders of magnitude leave unchanged the kinetics of rejoining of DNA DSBs, and fail to modify the contribution of the slow component in a way compatible with a dependence on HR. We propose that, in contrast to yeast, cells of vertebrates are 'hard-wired' in the utilization of NHEJ as the main pathway for rejoining of IR-induced DNA DSBs and speculate that the contribution of homologous recombination repair (HRR) is at a stage after the initial rejoining.

Genetic evidence for the involvement of DNA ligase IV in the DNA-PK-dependent pathway of non-homologous end joining in mammalian cells

Cells of vertebrates remove DNA double-strand breaks (DSBs) from their genome predominantly utilizing a fast, DNA-PKcs-dependent form of non-homologous end joining (D-NHEJ). Mutants with inactive DNA-PKcs remove the majority of DNA DSBs utilizing a slow, DNA-PKcs-independent pathway that does not utilize genes of the RAD52 epistasis group, is error-prone and can therefore be classified as a form of NHEJ (termed basic or B-NHEJ). We studied the role of DNA ligase IV in these pathways of NHEJ. Although biochemical studies show physical and functional interactions between the DNA-PKcs/Ku and the DNA ligase IV/Xrcc4 complexes suggesting operation within the same pathway, genetic evidence to support this notion is lacking in mammalian cells. Primary human fibroblasts (180BR) with an inactivating mutation in DNA ligase IV, rejoined DNA DSBs predominantly with slow kinetics similar to those observed in cells deficient in DNA-PKcs, or in wild-type cells treated with wortmannin to inactivate DNA-PK. Treatment of 180BR cells with wortmannin had only a small effect on DNA DSB rejoining and no effect on cell radiosensitivity to killing although it sensitized control cells to 180BR levels. This is consistent with DNA ligase IV functioning as a component of the D-NHEJ, and demonstrates the unperturbed operation of the DNA-PKcs-independent pathway (B-NHEJ) at significantly reduced levels of DNA ligase IV. In vitro, extracts of 180BR cells supported end joining of restriction endonuclease-digested plasmid to the same degree as extracts of control cells when tested at 10 mM Mg(2+). At 0.5 mM Mg(2+), where only DNA ligase IV is expected to retain activity, low levels of end joining ( approximately 10% of 10 mM) were seen in the control but there was no detectable activity in 180BR cells. Antibodies raised against DNA ligase IV did not measurably inhibit end joining at 10 mM Mg(2+) in either cell line. Thus, in contrast to the situation in vivo, end joining in vitro is dominated by pathways with properties similar to B-NHEJ that do not display a strong dependence on DNA ligase IV, with D-NHEJ retaining only a limited contribution. The implications of these observations to studies of NHEJ in vivo and in vitro are discussed.

Nonhomologous end-joining of ionizing radiation-induced DNA double-stranded breaks in human tumor cells deficient in BRCA1 or BRCA2

Mutations in the BRCA1 or BRCA2 genes predispose to a wide spectrum of familial cancers. The functions of the proteins encoded by BRCA1 and BRCA2 remain to be elucidated, but their interaction and colocalization with hRAD51 suggest a role in homologous recombination and DNA double-strand break (DSB) repair. The role of BRCA1 and BRCA2 in the rejoining of ionizing radiation (IR)-induced DNA DSBs, which may represent a step in the overall process of repair, remains uncertain because recent reports provide conflicting results. Because elucidation of the role of these proteins in DNA DSB rejoining is important for their functional characterization, we reexamined this end point in cells with mutations in either BRCA1 or BRCA2. We show that two pancreatic carcinoma cell lines known to have either wild-type (BxPC3) or mutant forms (Capan-1) of BRCA2 rejoin IR-induced DNA DSBs to a similar extent following biphasic kinetics characterized by a fast and a slow component. Importantly, inactivation of DNA-dependent protein kinase (DNA-PK) by wortmannin generates similar shifts from the fast to the slow component of rejoining in BRCA2-proficient and BRCA2-deficient cells. This suggests that the functioning of either the fast, DNA-PK-dependent component or the slow, DNA-PK-independent component of rejoining is not affected by mutations in BRCA2. Also, a human breast cancer cell line with mutated BRCA1 shows normal rejoining of IR-induced DNA DSBs and levels of inhibition by wortmannin commensurate with the degree of DNA-PK inhibition. These observations fail to confirm a direct role for BRCA1 or BRCA2 in the rejoining of IR-induced DSBs in the genome of human tumor cells and, as a result, an involvement in nonhomologous end-joining. They are in line with similar observations with mutants deficient in genes implicated in homologous recombination and support the view that the radiosensitivity to killing of cells deficient in BRCA1 or BRCA2 derives from defects in this repair pathway.

Homologous recombination as a potential target for caffeine radiosensitization in mammalian cells: reduced caffeine radiosensitization in XRCC2 and XRCC3 mutants

The radiosensitizing effect of caffeine has been associated with the disruption of multiple DNA damage-responsive cell cycle checkpoints, but several lines of evidence also implicate inhibition of DNA repair. The role of DNA repair inhibition in caffeine radiosensitization remains uncharacterized, and it is unknown which repair process, or lesion, is affected. We show that a radiosensitive cell line, mutant for the RAD51 homolog XRCC2 and defective in homologous recombination repair (HRR), displays significantly diminished caffeine radiosensitization that can be restored by expression of XRCC2. Despite the reduced radiosensitization, caffeine effectively abrogates checkpoints in S and G2 phases in XRCC2 mutant cells indicating that checkpoint abrogation is not sufficient for radiosensitization. Another radiosensitive line, mutant for XRCC3 and defective in HRR, similarly shows reduced caffeine radiosensitization. On the other hand, a radiosensitive mutant (irs-20) of DNA-PKcs with a defect in non-homologous end-joining (NHEJ) is radiosensitized by caffeine to an extent comparable to wild-type cells. In addition, rejoining of radiation-induced DNA DSBs, that mainly reflects NHEJ, remains unaffected by caffeine in XRCC2 and XRCC3 mutants, or their wild-type counterparts. These observations suggest that caffeine targets steps in HRR but not in NHEJ and that abrogation of checkpoint response is not sufficient to explain radiosensitization. Indeed, immortalized fibroblasts from AT patients show caffeine radiosensitization despite the checkpoint defects associated with ATM mutation. We propose that caffeine radiosensitization is mediated by inhibition of stages in DNA DSB repair requiring HRR and that checkpoint disruption contributes by allowing these DSBs to transit into irreparable states. Thus, checkpoints may contribute to genomic stability by promoting error-free HRR.

Phase I clinical trial of oral furtulon and combined hepatic arterial chemoembolization and radiotherapy in unresectable primary liver cancers, including clinicopathologic study

Surgical resection has been accepted as the only curative therapy for primary liver cancer (PLC). Unfortunately, most patients are surgically unresectable when they seek treatment. An alternative therapeutic approach for some of these patients is transcatheter arterial chemoembolization. However, this is not curative by itself, and additional therapy is required to eradicate residual disease. This study investigates the approach of preoperative hepatic arterial chemoembolization followed by the combination of oral Furtulon (5'-deoxy-5-fluorouridine) as a radiosensitizer and external beam radiotherapy (RT). From July 1997 to December 1998, 25 patients with unresectable PLC were treated with hepatic arterial chemoembolization followed by limited-field radiotherapy plus oral Furtulon as a radiosensitizer. Hepatic arterial chemoembolization was performed with 5-fluorouracil 1 g, cisplatin 80 mg (DDP), mitomycin C (MMC) 10 mg, and arterial embolization with iodized oil-10 ml mixed with 10 mg MMC. Hepatic arterial chemoembolization was performed at regular intervals of 6 weeks, and the patients then received limited-field RT. Mean tumor dose was 4,600 cGy (range, 4,100-5,200 cGy) in daily 1.8-Gy fractions, 5 times a week. The toxicity and responses between RT and surgery were assessed. After surgical evaluation, resection was performed. The histopathologic study was also performed in the specimens of both normal and radiation-injured liver tissues from the patients who underwent resection. Seventeen of 25 patients (68%) showed an objective response. One patient with cholangiocarcinoma involving the portal lymph nodes attained a complete response. Eight patients (32%) underwent sequential resection. The most common toxicity was an increase in liver enzymes, which were less than twofold of the upper limit of normal. Follow-up computed tomography studies after treatment showed a low-attenuation area adjacent to the hepatic tumor in the target volume. On pathologic evaluation, the low-attenuation area revealed hyperemia, distended hepatic sinusoids packed with erythrocytes, and hepatic cell loss when examined with microscopy; "new-born" hepatocytes, hepatic cords in the process of forming, and endothelial cells have appeared on electronic microscopic examination. The combination of hepatic arterial chemoembolization and external radiotherapy is efficacious and a safe modality for unresectable primary liver cancers. Furtulon offers the potential for use as a clinical radiosensitizer. Radiation can significantly damage the liver tissue between 41 Gy and 52 Gy, but the new hepatocytes were forming within the radiation-injured liver after RT.

DNA-dependent protein kinase stimulates an independently active, nonhomologous, end-joining apparatus

Double-strand breaks (DSBs) can be efficiently removed from the DNA of higher eukaryotes by nonhomologous end-joining (NHEJ). Genetic studies implicate the DNA-dependent protein kinase (DNA-PK) in NHEJ, but the exact function of this protein complex in the rejoining reaction remains to be elucidated. We compared rejoining of DNA DSBs in a human glioma cell line, M059-J, lacking the catalytic subunit of DNA-PK (DNA-PKcs), and their isogenic but DNA-PK-proficient counterpart, M059-K. In both cell lines, rejoining of DNA DSBs was biphasic, with a fast and a slow component operating with a half-life of approximately 22 min and 12 h, respectively. Deficiency in DNA-PK activity did not alter the half-times of either of these components of rejoining but increased from 17 to 72% the proportion of DNA DSB rejoining with slow kinetics. DNA DSB rejoining was nearly complete in both cell lines, and there was only a small increase in the number of unrejoined breaks in M059-J as compared with M059-K cells after 30 h of incubation. Wortmannin radiosensitized to killing M059-K cells and strongly inhibited DNA DSB rejoining. Wortmannin did not affect the radiosensitivity to killing and produced only a modest inhibition in DNA DSB rejoining in M059-J cells, suggesting that, for these end points, DNA-PK is the principal target of the drug. These observations demonstrate that DNA-PK deficiency profoundly decreases the proportion of DNA DSB rejoining with fast kinetics but has only a small effect on the fraction remaining unrejoined. We propose that in higher eukaryotes, an evolutionarily conserved, independently active, but inherently slow NHEJ pathway is stimulated 30-fold by DNA-PKcs to rapidly remove DNA DSBs from the genome. The stimulation is expected to be of local nature and the presence of DNA-PKcs in the vicinity of the DNA DSB determines whether rejoining will follow fast or slow kinetics. Structural and regulatory functions of DNA-PKcs may mediate this impressive acceleration of DNA DSB rejoining, and regions of chromatin within a certain range from this large protein may benefit from these activities. We propose the term DNA-PK surveillance domains to describe these regions.

Improved long-term survival for unresectable hepatocellular carcinoma (HCC) with a combination of surgery and intrahepatic arterial infusion of 131I-anti-HCC mAb. Phase I/II clinical trials

Resectional therapy has been accepted as the only curative therapy for hepatocellular carcinoma (HCC). Unfortunately, it is estimated that only 10% of HCC are resectable at the time of diagnosis. Cytoreduction and sequential resection offer a new hope for patients with unresectable HCC. Radioimmunotherapy (RIT) is an attractive approach for cytoreduction. We have previously shown that intrahepatic arterial 131I-labelled anti-HCC monoclonal antibody (131I-Hepama-1 mAb) could be used safely in combination with hepatic artery ligation for treatment of unresectable HCC, and encouraging results have been achieved. In this paper, the long-term survival and the prognostic factors in HCC patients treated with radioimmunotherapy will be analysed. Sixty-five patients with surgically verified unresectable HCC were treated with hepatic artery ligation plus hepatic artery cannulation and infusion from 1990 to 1992. Thirty-two patients were enrolled in a phase I-II clinical trial with infusion of 131I-radiolabelled anti-HCC monoclonal antibody (Hepama-1 mAb) via the hepatic artery (the RIT group). Another 33 patients formed the group treated with intrahepatic-arterial chemotherapy (the non-RIT group). T cell subsets were measured in 24 patients and human anti-(murine Ig) antibody (HAMA) were monitored in the RIT group. The 5-year survival rate was significantly higher in the RIT group than in the chemotherapy group, being 28.1% compared to 9.1% (P < 0.05); this was mainly a result of better cytoreduction and a higher sequential resection rate (53.1% compared to 9.1%). Significant prognostic factors in the RIT group included tumour capsule status and the number of tumour nodules. HAMA incidence and CD4+ T lymphocytes influenced short-term, but not long-term survival. It is suggested that intrahepatic-arterial RIT, using 131I-Hepama-1 mAb, combined with hepatic artery ligation might be an effective approach to improve long-term survival in some patients with unresectable HCC, which may successfully be made resectable by intra-arterial infusion of 131I-Hepama-1 mAb.

Photosensitization of bilirubin on proliferation and DNA synthesis in ascitic hepatoma cells

AIM

To observe the effects and its mechanism of photosensitization of bilirubin on ascitic hepatoma (Hep A) cells.

METHODS

After the cells were illuminated under the light (1.0 x 10(5) lx) for 10 min, deoxy[3H]thymidine was added for DNA synthesis assay. The cells were dyed with 0.5% trypan blue and were counted.

RESULTS

The cell mortality of illuminated groups were much higher than that of dark groups (P < 0.01). The inhibitions of DNA synthesis of illuminated groups were stronger than that of dark groups (P < 0.01). The cell mortality and inhibition of DNA synthesis of illuminated groups were positively dependent upon the concentrations of bilirubin and illuminating time. No difference of DNA synthesis between room light illumination groups and dark groups (P < 0.05).

CONCLUSION

The photosensitization of bilirubin killed Hep A cells obviously. Bilirubin under room light had no effect on inhibition of DNA synthesis. The photosensitization of bilirubin was closely related to 1O2 and H2O2 and not to OH. and O2-. Bilirubin, the end product of heme catabolism in mammals, is a potentially cytotoxic, lipid soluble waste product that needs to be excreted. However, bilirubin at micromolar concentration in vitro, efficiently scavenges peroxyl radicals. In liposomes, bilirubin suppresses the antioxidation more than alpha-tocopherol, which is regarded as the best antioxidant of lipid peroxidation. Thus bilirubin is a physiological, chain-breaking antioxidant. Bilirubin exhibited antitumor activity and acted as a photosensitizer with four pyrrole rings. Many photosensitizers have been used to treat cancer due to their photosensitization. In this paper, the photosensitization of bilirubin on DNA synthesis in ascitic hepatoma (Hep A) cells and on cell mortality were studied.

Observation of changes in peripheral T-lymphocyte subsets by flow cytometry in patients with liver cancer treated with radioimmunotherapy

An analysis of lymphocyte subsets was performed in 24 patients with surgically verified unresectable hepatocellular carcinoma (HCC). In all cases, the hepatic artery was cannulated and ligated and a single dose of 131I-Hepama-1 monoclonal antibody (MAb) was infused through a hepatic artery catheter. Blood samples were obtained before infusion and 1 month post-infusion. The results indicated that the CD3+ T-cells (pan T-cells) were normal, whereas the CD4+ T-cells (T-helper/inducer cells) decreased and the CD8+ T-cells (T-suppressor/cytotoxic cells) increased significantly in comparison with the control group. So the CD4+:CD8+ ratio declined markedly. One month post-radioimmunotherapy (RIT), the T-cell subsets did not change, but CD4+, CD8+ and the CD4+:CD8+ ratio differed significantly between patients with and without sequential resection. The changes in the T-cell subsets were closely related to tumour capsule status and the human anti-murine antibody (HAMA) response, but no relationship was found between the tumour and administration of a moderate dose of radioimmunoconjugate. Therefore, determination of changes in the T-lymphocyte subsets and the CD4+:CD8+ ratio could be used as clinical and prognostic indicators in patients who have received RIT. Furthermore, RIT did not affect the distribution of T-cell subsets in patients with HCC.

Treatment of unresectable primary liver cancer: with reference to cytoreduction and sequential resection

Unquestionably, progress has been made in the early detection and early treatment of primary liver cancers (PLCs), although most remain unresectable, mainly because the cancer is advanced and coexists with liver cirrhosis, particularly in Oriental patients. Thanks to the progress of regional cancer therapy, a multidisciplinary approach, and changing concepts about surgical oncology, it has been proved that some unresectable but not far advanced PLCs are potentially convertible to being resectable, particularly those cancers confined to the right lobe of a cirrhotic liver. A retrospective analysis of 571 unresectable PLCs revealed the following: (1) There was an increase in 5-year survivals in the series, from 0% during the 1960s (n = 61), to 4.8% during the 1970s (n = 163), to 21.2% during the 1980s (n = 347). It might be a result of the increase in double- or triple-modality treatments in these series (from 9.8%, to 19.6%, to 70.3%, respectively) and in the sequential resection rate after cytoreduction (from 0%, to 2.5%, to 14.7%). (2) The combination of hepatic artery ligation, hepatic artery cannulation and infusion, and intrahepatic arterial radioimmunotherapy has resulted in better shrinkage of the tumor, a higher sequential resection rate, and a higher 5-year survival (28.2%). (3) Of the 55 patients who had initially unresectable PLCs and yielded "cytoreduction and sequential resection," the 5-year survival was 58.5%. It is concluded that cytoreduction and sequential resection might be an important approach to improving the prognosis of patients with unresectable PLCs.

Human anti-(murine Ig) antibody responses in patients with hepatocellular carcinoma receiving intrahepatic arterial 131I-labeled Hepama-1 mAb. Preliminary results and discussion

Human anti-(murine Ig) antibody (HAMA) responses were monitored in 32 patients with unresectable hepatocellular carcinoma (HCC) undergoing radioimmunotherapy using 131I-labeled anti-HCC monoclonal antibody (Hepama-1 mAb) intrahepatic arterial infusion. Dosages of Hepama-1 mAb ranged from 5 mg to 20 mg and the mAb was radiolabeled with 0.74-4.00 GBq (20-108 mCi) 131I (4-6 mCi/mg). T lymphocyte subsets were examined before and after radioimmunotherapy in 24 patients. In this series, 34.4% (11/32) of patients developed HAMA within 2-4 weeks after the infusion. All patients with a negative HAMA response (n = 14), had CD4+ T lymphocyte subsets (T helper/inducer) much lower than those of the HAMA-positive (n = 10) patients and the control group (n = 40) (P < 0.01) prior to infusion. The sequential resection and survival rates in the HAMA-negative group were also lower than that of the HAMA-positive group. Thus, the determination of T lymphocyte subsets might help to predict the HAMA response in HCC patients during radioimmunotherapy.

Radioimmunotherapy for unresectable hepatocellular carcinoma using 131I-Hepama-1 mAb: preliminary results

Twenty-three patients with surgically verified unresectable hepatocellular carcinoma (HCC) have been treated by intrahepatic arterial administration of 131I-labeled anti-HCC monoclonal antibody (Hepama-1) combined with hepatic artery ligation. Radioimmunoimaging demonstrated that the median tumor/liver ratio was 2.1 (1.1-3.6) at day 5. A decline in alpha-fetoprotein level and shrinkage of tumor were observed in 75% (12/16) and 78% (18/23) of patients respectively. Sequential resection was done in 11 patients (48%) after treatment. The surgical specimens revealed massive necrosis of tumor, but residual cancer cells were found at the edge of the specimens. Anti-antibody was determined in 43% (10/23) of patients 2-4 weeks after the administration of 131I-Hepama-1 mAb. No marked toxic effects were noted. It is suggested that 131I-Hepama-1 mAb might be of value as one of the multimodality treatments for unresectable HCC.

[Anatomic study of longitudinal cutting of the right hepatic duct]

6 fresh liver from adult human specimen to casting model by perfusing with A. B. S. acetone solution and 42 formalin-fixated livers (adult 32 and children 10) were used in present study. The whole length and inner-diameter of the right hepatic duct as well as the angle between right and common hepatic duct were measured. The right hepatic duct were cut open longitudinally and their relations were classified. The relationship among the right hepatic duct and the right hepatic artery, the right trunk of portal vein and its branches, as well as gallbladder bed were observed. The method and the cautions in the operation of Longitudinal cutting of the right hepatic duct were described.

Phosphorylation of the carotenoid droplet protein p57 by the catalytic subunit of cyclic adenosine monophosphate-dependent protein kinase and the effect of fluoride

We have previously shown that the dispersion and aggregation of carotenoid droplets in goldfish xanthophores are regulated, respectively, by phosphorylation and dephosphorylation of a carotenoid droplet protein p57. There is a basal level of p57 phosphorylation of p57 in unstimulated cells, which is greatly stimulated by adrenocorticotropic hormone (ACTH) or cyclic adenosine monophosphate (cAMP) acting via cAMP-dependent protein kinase. We have also observed that, in permeabilized xanthophores, pigment dispersion can be induced when cAMP is replaced by fluoride. Since p57 has multiple phosphorylation sites, there is the question of whether all p57 phosphorylation is by cAMP-dependent protein kinase or whether phosphorylation by cAMP-independent protein kinase coupled with inhibition of phosphatase activity by fluoride can replace cAMP-dependent protein kinase and that the ability of fluoride to replace cAMP for pigment dispersion in permeabilized cells is probably due to activation of adenylcyclase. We also show that ACTH causes an approximately threefold increase in the level of cAMP in these cells.

Purification of anterogin, a protein factor necessary for the dispersion of carotenoid droplets in permeabilized xanthophores of goldfish

We reported previously that the dispersion of carotenoid droplets in permeabilized xanthophores requires cAMP, ATP, and a cytosolic factor present in several secretory tissues as well as in xanthophores. We have now purified this factor from beef liver to apparent/near homogeneity. It appears to be a heterodimer with Mr approximately 125,000. The purified factor has little or no ATPase activity, with or without the presence of actin. Nor does it stimulate the ATPase activity of carotenoid droplets. Its exact function in carotenoid droplet dispersion is thus unclear. Since dispersion of carotenoid droplets is an anterograde translocation, we propose the name anterogin for this protein. We also report that yeast cytosol has anterogin activity.