Pilot study of local radiotherapy for portal vein tumor thrombus in patients with unresectable hepatocellular carcinoma

BACKGROUND

Patients suffering from hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) generally have a poor prognosis. We therefore conducted a prospective pilot trial of combined transcatheter arterial chemoembolization (TACE) and local radiotherapy (RT) for PVTT in unresectable HCC. The aim of the study was to investigate the efficacy and toxicity of this preliminary trial regime and to explore RT guidelines for cirrhosis.

METHODS

Eight patients with unresectable HCC accompanied by first branch PVTT were entered into the study from February 1998 to December 1999. TACE was performed using Lipiodol, epirubicin hydrochloride and mytomycin followed by gelatin sponge cubes. RT was started 10-14 days following TACE. A total delivered dose of 60 Gy was given as daily 2 Gy fractions, with the clinical target volume defined as PVTT only. We observed a relationship between deterioration of liver function and the percent volume of the total liver receiving a dose exceeding 30 Gy (V30).

RESULTS

An objective response was observed in three of the eight patients. However, on follow-up angiograms the protrusion of PVTT into the main portal trunk was decreased in all cases. Deterioration of liver function was observed in all patients with V30 >40%.

CONCLUSION

It is possible that this combined therapy prevents PVTT from spreading to the main trunk and that indicates a further benefit of TACE. Our results indicate that V30 constitutes a predictive test for the development of liver failure. More detailed evaluations of liver function and determination of the safe irradiation volume are necessary.

Prenatal ionizing radiation-induced apoptosis of the developing murine brain with special references to the expression of some proteins

Apoptosis induced by ionizing irradiation of the developing mouse brain was investigated by using histology, analysis of DNA fragmentation on agarose gel and electron microscopy. A TUNEL-labeled index (L.I.) was calculated from the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) assay in 4 specific regions, cortical plate, intermediate zone, subependymal zone, and subependymal germinal matrix. The kinetics of apoptosis associated protein was examined by western blotting and immunofluorescence. C57BL/6J mice pregnant on embryonic day 14 (E14) were exposed to a single dose of 1.5-Gy irradiation. Irradiated fetal brains at E15 and E17 showed extensive apoptosis with morphological characteristics. In all 4 regions, L.I. was greater in irradiated brains than in control brains at E15 and E17. Most of TUNEL-labeled cells expressed a mature neuronal marker (NeuN) and Bax protein, which is up-regulated in irradiation-induced apoptosis. Ionizing radiation moderately enhanced expression of Bax, Bcl-xL, and Cpp32 proteins. Postnatal irradiated mice showed microencephaly as compared to age-matched mice and the weight of whole body including brain decreased moderately.

Expression of human brain carboxypeptidase B, a possible cleaving enzyme for beta-amyloid precursor protein, in peripheral fluids

Human brain carboxypeptidase B (HBCPB) is a novel brain protease that processes native brain beta-amyloid precursor protein (APP) in vitro. Immunoblot analysis of human serum and cerebrospinal fluid (CSF) using anti C14-module antibody, which recognizes the C-terminal peptide unique to HBCPB, detected the 30 and 40 kDa immunoreactive bands. Analysis of HBCPB prepared from both serum and CSF demonstrated proteolytic activities for brain APP. Protease inhibitor spectrum analysis also supports that these bands correspond to the mature form and and prepro form of HBCPB, respectively. As is the case in brain parenchyma, the prepro-form is dominant in CSF. In serum, however, the majority of HBCPB exists in the mature form, possibly due to an abundant trypsin-like proteolytic activity in serum. HBCPB expressed in serum and CSF, therefore, may have a significance as a peripheral marker of the brain protease, which participates in APP processing in human brain.

Inhibition of erythropoietin signalling destroys xenografts of ovarian and uterine cancers in nude mice

We have recently shown that malignant tumours from the ovary and uterus expressed erythropoietin (Epo) and its receptor (EpoR), and that deprivation of Epo signal in tumour blocks induced death of malignant cells and capillary endothelial cells in vitro (Yasuda et al, submitted). These in vitro results prompted us to examine the effect of Epo-signal withdrawal on tumours in vivo. RT-PCR analysis demonstrated the expression of mRNAs for Epo and EpoR in the transplants of uterine and ovarian tumours in nude mice. Then we injected locally anti-Epo antibody or soluble form of EpoR into the transplants. At 12 h, 1, 7 or 14 days after the injection, all transplants were resected and examined macro- and microscopically. Tumour size was reduced in Epo signal-deprived transplants. Immunohistochemical examinations revealed destruction of Epo-responding malignant and capillary endothelial cells through apoptotic death. The degree of tumour regression correlated well with the dose and frequency of the injections. Control xenografts with saline injection or needle insertion showed well-developed tumour masses. This Epo response pathway will have profound implications for our understanding of the development and progression of malignant tumours and for the use of Epo-signal deprivation as an effective therapy.

A novelCLCN1 mutation: P480T in a Japanese family with Thomsen's myotonia congenita

At least 50 disease-causing mutations in the skeletal muscle voltage-gated chloride channel gene (CLCN1), almost all of which originate from Caucasian families, have been identified. We investigated a Japanese family with Thomsen's myotonia congenita that included 16 affected individuals (8 men and 8 women) through five generations. Polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) screening of 11 members showed an aberrant conformer in exon 13 of CLCN1 complementary DNA (cDNA) in 8 affected and 1 unaffected members. By sequence analysis, we identified a C-to-A transition at nucleotide position 1438, resulting in a substitution of proline for threonine at amino acid position 480 (P480T), the same position of the original mutation (P480L) in Thomsen's disease. The P480T mutation was novel and absent in 100 normal controls. Seven of the 8 affected individuals were heterozygous; another, from affected parents, was homozygous. Clinically, myotonia in the homozygous patient was more severe than that in heterozygous patients, probably due to the gene dosage effect. On a long-train nerve-stimulation test at a rate of 3 Hz, M-wave responses in the homozygous patient showed marked decrement followed by recovery. In contrast, the heterozygous patients showed just a slight decrement or no changes, and none of 2 patients with myotonic muscular dystrophy or 2 normal controls revealed any decrement. Thus, the long-train nerve-stimulation test at a low stimulus frequency may be a useful tool to assess the disease-severity/genotype relationship in myotonia congenita.

In vivo gene electroporation in skeletal muscle with special reference to the duration of gene expression

To determine the limits of the duration of in vivo transferred foreign gene expression, we conducted electroporation (EP), a powerful non-viral means of gene transfer for living animals, into skeletal muscle of rats and mice with a luciferase, GFP or erythropoietin (EPO)-encoding reporter plasmid. The luciferase reporter plasmid was used for optimization of EP conditions, while GFP and EPO plasmids were used for monitoring the duration of gene expression. In the rat, increased hematocrit levels were maintained for at least 9 weeks with approximately a 3-fold increase in plasma EPO protein concentration at 4 weeks post-transfection. In the mouse, the GFP plasmid transfer confirmed that the reporter gene expression lasted as long as 3 months post-transfection. By introducing the EPO gene in vivo in the mouse, increased hematocrit levels revealed that duration of reporter gene expression was at least 14.5 months after in vivo gene EP into skeletal muscle. These results implicate an excellent potential of in vivo gene EP, applicable to both experimental and therapeutic purposes.

Growth and secretion of erythropoietin of Chinese hamster ovary cells coexpressing epidermal growth factor receptor and erythropoietin genes: Design of cells for cell culture matrix

Chinese hamster ovary (CHO) cells were transfected withboth genes encoding erythropoietin (Epo) and epidermal growthfactor receptor (EGFR). The transfection of the Epo gene wasconfirmed by an enzyme-linked immunoassay. Overexpression ofEGFR was confirmed by Western blotting of EGFR. Thetransfected CHO cells were cultured in serum-free medium inthe presence of soluble epidermal growth factor (EGF) orimmobilized EGF. The CHO cells overexpressing EGFR grew in thepresence of less EGF than the cells not overexpressing EGFR.In addition, the growth of EGFR-overexpressing CHO cells wasenhanced in the presence of immobilized EGF more efficientlythan in the presence of soluble EGF. The amount of Eposecreted from the cells increased linearly with the increaseof growth rate. Consequently, culture of CHO cellscoexpressing Epo and EGFR on EGF-immobilized matrix was themost efficient for Epo production.

Tissue-specific regulation of erythropoietin production in the murine kidney, brain, and uterus

Erythropoietin (Epo) produced by the kidney regulates erythropoiesis. Recent evidence suggests that Epo in the cerebrum prevents neuron death and Epo in the uterus induces estrogen (E(2))-dependent uterine angiogenesis. To elucidate how Epo expression is regulated in these tissues, ovariectomized mice were given E(2) and/or exposed to hypoxia, and the temporal patterns of Epo mRNA levels were examined. Epo mRNA levels in the kidney and cerebrum were elevated markedly within 4 h after exposure to hypoxia. Although the elevated level of Epo mRNA in the kidney decreased markedly within 8 h despite continuous hypoxia, the high level in the cerebrum was sustained for > or = 24 h, indicating that downregulation operates in the kidney but not in the brain. E(2) transiently induced Epo mRNA in the uterus but not in the kidney and cerebrum. Interestingly, the uterine Epo mRNA was hypoxia inducible only in the presence of E(2). Thus Epo expression appears to be regulated in a tissue-specific manner, endorsing the tissue-specific functions of Epo.

Complete genome sequence of the alkaliphilic bacterium Bacillus halodurans and genomic sequence comparison with Bacillus subtilis

The 4 202 353 bp genome of the alkaliphilic bacterium Bacillus halodurans C-125 contains 4066 predicted protein coding sequences (CDSs), 2141 (52.7%) of which have functional assignments, 1182 (29%) of which are conserved CDSs with unknown function and 743 (18. 3%) of which have no match to any protein database. Among the total CDSs, 8.8% match sequences of proteins found only in Bacillus subtilis and 66.7% are widely conserved in comparison with the proteins of various organisms, including B.subtilis. The B. halodurans genome contains 112 transposase genes, indicating that transposases have played an important evolutionary role in horizontal gene transfer and also in internal genetic rearrangement in the genome. Strain C-125 lacks some of the necessary genes for competence, such as comS, srfA and rapC, supporting the fact that competence has not been demonstrated experimentally in C-125. There is no paralog of tupA, encoding teichuronopeptide, which contributes to alkaliphily, in the C-125 genome and an ortholog of tupA cannot be found in the B.subtilis genome. Out of 11 sigma factors which belong to the extracytoplasmic function family, 10 are unique to B. halodurans, suggesting that they may have a role in the special mechanism of adaptation to an alkaline environment.

Identification of a sequential B-cell epitope on major allergen (Cry j 1) of Japanese cedar (Cryptomeria japonica) pollen in mice

BACKGROUND

Japanese cedar (Cryptomeria japonica; CJ) pollinosis is one of the most common allergic diseases in Japan. B cell epitopes on Cry j 1, a major allergen of CJ pollen, have been analyzed by the specific monoclonal antibodies to Cry j 1, and most of these epitopes may be conformational, but no previous report has addressed the analysis of sequential epitope mapping with synthetic peptides. The main purpose of the present study is to identify IgE and IgG B cell epitopes on Cry j 1 by using a synthetic peptide approach in mice.

METHODS

We synthesized 35 overlapping peptides that cover the entire length of Cry j 1 and examined whether mouse IgE and IgG antibodies produced by immunization with Cry j 1 reacted to the Cry j 1 peptides.

RESULTS AND CONCLUSION

We found that mouse IgE and IgG antibodies reacted strongly to Cry j 1 peptide No. 15 ((141)GVEPVHPQDGDALTLRTATN(160)), though those antibodies did not react with other peptides. IgE and IgG antibody binding to peptide No. 15 was completely inhibited by Cry j 1 and the peptide. To determine the minimum epitope in peptide No. 15, we conducted an ELISA inhibition test. IgE and IgG antibody binding to peptide No. 15 was inhibited by smaller peptides of this peptide. We found the core of the epitope to be (145)VHPQDGDA(152).

Retinoic acid stimulates erythropoietin gene transcription in embryonal carcinoma cells through the direct repeat of a steroid/thyroid hormone receptor response element half-site in the hypoxia-response enhancer

We have previously reported that expression of the erythropoietin (Epo) gene in mouse embryonal cells was not induced by hypoxia, although hypoxia induced other hypoxia-inducible genes. This study identifies retinoic acid (RA) as an inducer for Epo production in the embryonal carcinoma cell lines P19 and F9. RA induced Epo production through the transcriptional activation of the Epo gene in an oxygen-independent manner. With the use of reporter assays in P19 cells, it is shown that a direct repeat of the nuclear hormone receptor-binding motif separated by a 2-bp spacer (DR-2) in the hypoxia-response enhancer was responsible for the transcriptional activation by RA. Electrophoretic mobility shift assays show that nuclear extracts from P19 cells contained RA receptor complexes that bound to DR-2. In human hepatoma Hep3B cells, an orphan receptor, hepatocyte nuclear factor-4, strongly augmented hypoxic induction of the Epo gene in cooperation with hypoxia-inducible factor-1 (HIF-1) by binding to DR-2, whereas in P19 cells, the interaction of RA receptors with DR-2 was sufficient for RA-induced transcriptional activation of the Epo gene without the requirement of the HIF-1 site. These results suggest that DR-2 regulates expression of the Epo gene by acting as the binding site for different transcription factors in different types of cells.

Increased risk of prostate cancer and benign prostatic hyperplasia associated with a CYP17 gene polymorphism with a gene dosage effect

The CYP17 gene (CYP17) codes for the cytochrome P450c17alpha enzyme, which mediates two key steps in the sex steroid synthesis. There is a polymorphism (a T-to-C substitution) in the 5'-untranslated region, which may influence the transcription level of CYP17 mRNA. There is a continuing controversy as to whether the variant allele is associated with a subset of breast cancer or polycystic ovary syndrome. In prostate cancer research, there are contradictory data concerning the CYP17 risk allele. We explored the association between CYP17 polymorphism and a risk of prostate cancer or benign prostatic hyperplasia (BPH) in a Japanese population. This study included 252 prostate cancer patients, 202 BPH patients, and 131 male controls. A 451-bp fragment encompassing the polymorphic site was amplified by PCR, treated with restriction enzyme MspA1, and electrophoresed on an agarose gel. The MspA1-undigested allele with the published sequence and the MspA1-digested variant allele were designated as A1 and A2, respectively. There was a significant difference (P < 0.05) in the genotypes between prostate cancer patients and male controls, and between BPH patients and male controls. Men with the A1/A1 CYP17 genotype had an increased risk of prostate cancer [odds ratio (OR), 2.57; 95% confidence interval (CI) = 1.39-4.78] and BPH (OR, 2.44; 95% CI = 1.26-4.72) compared with those with the A2/A2 genotype. Men with the A1/A2 genotype had an intermediate increased risk of prostate cancer (OR, 1.45; 95% CI = 0.84-2.54) and BPH (OR, 1.60; 95% CI = 0.89-2.87) compared with those with the A2/A2 genotype. The trend of an increasing risk of prostate cancer and BPH with an increasing number of the A1 allele was statistically significant (prostate cancer versus male control, P = 0.003; OR, 1.57; 95% CI = 1.16-2.12; BPH versus male control, P = 0.008; OR, 1.55; 95% CI = 1.12-2.13). There was no significant association between the CYP17 genotype and the tumor status (grade and stage) of prostate cancer. Our results suggest that the A1 allele of the CYP17 polymorphism is associated with an increased risk of prostate cancer and BPH, with a gene dosage effect. However, the CYP17 genotype does not seem to influence the disease status in prostate cancer.

Erythropoietin: multiple physiological functions and regulation of biosynthesis

Erythropoietin (Epo), which is produced by the kidney in the adult and by the liver in the fetus, increases red blood cells by supporting the survival of erythroid progenitor cells and stimulating their differentiation and proliferation via binding to Epo receptor (EpoR). The main signal in the control of Epo production is oxygen; hypoxia stimulates Epo production through activation of Epo gene transcription. Tremendous progress in our understanding of molecular mechanisms of Epo action on erythroid cells and regulation of the Epo production has been made by manipulation of cDNAs and genes of Epo and EpoR. Studies on hypoxic induction of Epo gene transcription led to the identification of hypoxia-inducible factor (HIF-1), a transcriptional factor, that functions as a global regulator of hypoxic gene expression. Paracrine Epo/EpoR systems that are independent of the endocrine erythropoietic system (kidney/bone marrow) have been found in the central nervous system and uterus. Novel functions of Epo at these local sites and tissue-specific regulation of Epo production including a newly found potent regulator (estrogen) have been proposed. The tissue-specific regulation rationalizes the specific functions of Epo produced by individual tissues.

Characterization and comparative study of the rrn operons of alkaliphilic Bacillus halodurans C-125

The ribosomal RNA operons (rrn) of alkaliphilic Bacillus halodurans C-125 were characterized and compared with those of B. subtilis. We isolated clones containing rrn operons from a lambda phage library of the C-125 chromosome, and the complete nucleotide sequence of each was determined. Eight rrn operons were identified by PFGE analysis of the C-125 chromosome digested with I-CeuI. The transcriptional orientation of the rrn operons mapped on the chromosome by Southern hybridization analysis was the same as the direction of replication of the chromosome. These operons were designated as rrnA-H, starting from the oriC locus in clockwise rotation. Sequence and structural analyses of these operons suggested that six of the rrn operons in the C-125 chromosome, rrnA, rrnB, rrnC-rrnD, rrnE, and rrnH, correspond to rrnO, rrnA, rrnJ-rrnW, rrnI, and rrnD in B. subtilis, whereas the other rrn operons (rrnF and rrnG) were specifically observed in C-125. The rrn loci were positioned from 0 degrees to 90 degrees on the physical map, with the oriC locus assigned the position zero degrees. Two ORFs annotated as tnpA and ykfC, whose gene products are likely to act as transposases, were found downstream of these six operons. Comparative analysis of the 16S-23S and 23S-5S ITS (internally transcribed sequence) regions of B. halodurans C-125 and those of B. subtilis revealed that the ITS regions in C-125 were much longer than those in B. subtilis. There was no substantial difference in the length of potential promoter sequences in B. halodurans and B. subtilis.

The clinical utility of measuring total PSA, PSA density, gamma-seminoprotein and gamma-seminoprotein/total PSA in prostate cancer prediction

BACKGROUND

To evaluate whether serum total prostate-specific antigen (PSA), PSA density (serum total PSA level divided by prostate volume), gamma-seminoprotein and gamma-seminoprotein/total PSA ratio could predict prostate cancer (PCa) prior to biopsy.

METHODS

A total of 316 consecutive patients who had undergone transrectal prostate biopsy and/or transurethral resection were examined. The prostate volume was determined by transrectal ultrasonography (TRUS) and the ability of the above-mentioned four variables to distinguish PCa from benign prostatic hyperplasia (BPH) was evaluated.

RESULTS

PCa was detected in 61 cases. Receiver-operating characteristic (ROC) analysis revealed that both the PSA density and serum total PSA were the most useful predictors of PCa among the four variables. For the patients with a serum total PSA level of 4.1-10.0 ng/ml, PSA density was significantly more accurate than total PSA (p < 0.005). An optimum PSA density value of 0.18 was chosen as a cutoff because it showed the highest sum of sensitivity and specificity, 92 and 54%, respectively. Using this PSA density cutoff, the number of biopsies could have been reduced to 57 from 63% when compared with a PSA density of 0.15.

CONCLUSIONS

PSA density was significantly more accurate than other variables in predicting PCa. To avoid unnecessary biopsies, the PSA density cutoff value of 0.18 would be recommendable for determining a prostate biopsy for Japanese males with a serum total PSA level of 4.1-10.0 ng/ml.

Widespread expression of alpha-synuclein and tau immunoreactivity in Hallervorden-Spatz syndrome with protracted clinical course

Hallervorden-Spatz syndrome (HSS) is a rare autosomal recessive disorder clinically characterized by extrapyramidal signs and progressive dementia. In a typical case, the clinical symptoms become apparent during late childhood, and usually the course is protracted over a decade or more. We recently had an opportunity to study the brains of two cases of HSS with a clinical course of over 30 years. Case 1 was a 44-year-old female and case 2 was a 37-year-old male. Grossly, the brains showed severe fronto-temporal lobar atrophy with abundant spheroids and mild iron deposits in the globus pallidus, associated with features of motor neuron disease. In addition, there was diffuse sponginess in the atrophic cortex as well as widespread Alzheimer's neurofibrillary tangles (NFTs) and Lewy bodies (LBs) in the cortical and subcortical regions, including the spinal cord. Ultrastructurally, NFTs were composed of paired helical filaments, and LBs of central dense cores with radiating fibrils. Discrete immunostaining was demonstrated in NFTs and neuropil threads with various antibodies against phosphorylated tau, and in LBs with antibody against alpha-synuclein. In addition, diffuse, overlapping immunoreactivity of alpha-synuclein and phosphorylated tau was seen within the cytoplasm of many neurons. However, when LBs and NFTs coexisted within the same neurons, they were clearly segregated. The findings of our present cases as well as those reported in the literature may indicate that simultaneous and extensive occurrence of abnormal phosphorylation of tau and accumulation of alpha-synuclein may constitute cardinal pathological features of HSS with protracted clinical course.

The efficacy of conventional radiation therapy in the management of pituitary adenoma

PURPOSE

To evaluate the efficacy of conventional radiotherapy for reducing tumor size and endocrine hypersecretion of pituitary adenomas.

METHODS AND MATERIALS

We reviewed the records of 91 patients with pituitary adenoma, who were first treated between 1969 and 1994 and had been followed for more than 2 years (median, 8.2 years.) Of these patients, 86 had received postoperative radiotherapy, and 5 had received radiotherapy alone. The median total dose was 51 Gy. Clinical symptoms related to mass effects or endocrine hypersecretion were assessed. The efficacy of radiotherapy was evaluated before treatment and during the follow-up period (1-14 years; median, 3 years) by estimating tumor size on computed tomography or magnetic resonance imaging in 56 patients, as well as by endocrine testing in the 22 patients who had secreting adenomas. Local control rate, prognostic factors, and side effects were analyzed.

RESULTS

Mass-effect symptoms improved in 72% and 79% of patients who had such symptoms due to nonsecreting adenomas and secreting adenomas, respectively. Symptoms of endocrine hypersecretion abated in 67% of patients who had such symptoms. Excessive hormone levels normalized in 74% of patients who showed endocrine hypersecretions. The greatest size reduction was seen 3 years after the completion of radiotherapy (24% CR, 62% PR, 12% NC, and 3% PD in nonsecreting adenomas, and 32% CR, 36% PR, 27% NC, and 5% PD in secreting adenomas). Three patients with secreting adenomas (2 with prolactinoma and 1 with Cushing's disease) showed a mismatch between reduction in tumor size and normalization of endocrine hypersecretion. The 10-year local control rates were 98%, 85%, 83%, and 67% for nonsecreting adenoma, growth-hormone-secreting adenoma, prolactinoma, and Cushing's disease, respectively. Univariate analyses showed that disease type and radiation field size were significant prognostic factors. Brain necrosis occurred in 1 patient who received a 60-Gy dose of irradiation.

CONCLUSION

We conclude that conventional external radiotherapy with 50 Gy is safe and sufficient to control pituitary adenoma. Careful observation is required in the management of secreting adenomas because the effects on tumor size and endocrine hypersecretion may be mismatched in some secreting adenomas.

The oviduct produces erythropoietin in an estrogen- and oxygen-dependent manner

Previously, we showed that erythropoietin (Epo) is produced in the mouse uterus, where Epo is indispensable for estrogen (E(2))-dependent angiogenesis. Expression of uterine Epo mRNA is stimulated by E(2) and hypoxia. The hypoxic induction requires the presence of E(2). In the present study, we examined other female reproductive organs in the mouse with respect to Epo mRNA expression and its stimuli (E(2) and hypoxia)-induced changes. Although Epo mRNA expression was seen in the ovary and oviduct, the E(2)-induced stimulation of Epo mRNA was found only in the oviduct. The E(2)-induced stimulation in the oviduct was transient and rapidly downregulated. Epo mRNA expression in the oviduct was hypoxia inducible, in both the presence and the absence of E(2). E(2)-dependent production of Epo and its mRNA expression were also found by use of cultured oviducts. The E(2) action is probably mediated through the E(2) receptor, and de novo protein synthesis is not required for E(2) induction of Epo mRNA. In the oviduct, the ampulla and isthmus regions produce Epo.

Target cells of apoptosis in the adult murine dentate gyrus and O4 immunoreactivity after ionizing radiation

The occurrence of radiation-induced apoptosis and the determination of target cells were investigated by using the TdT-mediated dUTP-biotin nick end labeling assay and immunohistochemical analyses. The O4 immunoreactivity, an oligodendrocytes surface antigen, was also evaluated by using western blotting analysis. C57BL/6J adult female mice were subjected to single dose irradiation of 10 Gy. Eight hours after irradiation, the most significant increase of apoptotic cells was detected in the subgranular zone and the hilus of the dentate gyrus. The target cells of radiation-induced apoptosis are the subgranular progenitor cells and the oligodendrocytes in the hilus. The amount of the O4 immunoreactivity, a marker for premature oligodendrocytes, was unchanged until 8 h but enhanced after 12 h of irradiation. These results are the first to show the increase of the O4 immunoreactivity after irradiation and may be associated with the pathogenesis of radiation injury.

A new biological strategy for high productivity of recombinant proteins in animal cells by the use of hypoxia-response enhancer

Oxygen supply is one of the major problems in the production of useful proteins by cultured animal cells and therefore it is of importance to devise a system by which a high productivity of human therapeutic recombinant proteins can be maintained or enhanced under low oxygen concentrations. A number of hypoxia-inducible genes have been found in animal cells and the induction in most cases is due to hypoxic activation of the gene transcription. A consensus sequence (HRE = hypoxia-response enhancer) responsible for the hypoxic activation exists in these genes and the binding of a protein, which is widely distributed in animal cells, to this sequence responding to hypoxia activates the promoter activity. The promoter of lactate dehydrogenase A gene is active in Chinese hamster ovary (CHO) cells and the vicinal HRE stimulates the promoter activity efficiently in hypoxia. We have prepared a number of permanent CHO cell lines producing recombinant human erythropoietin (Epo) under control of this promoter/HRE. Epo production was highly hypoxia-inducible when the wild-type of HRE was used but uninducible when the mutant HRE was used. There was little difference in the in vitro and in vivo activities, and glycosylation between Epo produced by the cells cultured in 21% and 2% oxygen. Furthermore, forced expression of hypoxia-inducible factor-1alpha (HIF-1alpha) enhanced Epo production in all oxygen concentrations. These results indicate that a biological strategy based on the hypoxic induction of gene transcription provides a novel system which guarantees a high productivity even uner low oxygen concentrations.

Association of vitamin D receptor gene polymorphism with prostate cancer and benign prostatic hyperplasia in a Japanese population

Recent studies have suggested that vitamin D is an important determinant of prostate cancer risk and inherited polymorphisms in the 3'-untranslated region (3'UTR) of the vitamin D receptor (VDR) gene are associated with the risk and progression of prostate cancer. This study was conducted to explore the association of VDR gene polymorphisms with prostate cancer risk in Japanese men who are considered to be much less influenced by environmental risk factors for prostate cancer. We studied 222 prostate cancer patients, 209 benign prostatic hyperplasia (BPH) patients, 128 male controls who were over 60 years old and without any evidence of prostate cancer or BPH, and 198 female controls. A PCR-RFLP method was used to determine three VDR gene polymorphisms in the 3'UTR characterized by restriction enzymes BsmI, ApaI and TaqI. In the BsmI polymorphism, heterozygosity or homozygosity for the absence of the BsmI restriction site was associated with one-third the risk of prostate cancer (P < 0.0001; odds ratio, 3.31; 95% confidence interval, 2.05-5.32) and with one-half the risk of BPH (P < 0.005; odds ratio, 2.07; 95% confidence interval, 1.33-3.22) compared with the male controls. The TaqI and ApaI polymorphisms did not show any significant association with either prostate cancer or BPH. The results indicate that the BsmI polymorphism in the VDR gene plays a significant role in protection against prostate cancer and BPH. Because of the racial difference in the strength of the linkage disequilibrium between the three polymorphisms, additional studies are required to apply the present results to other racial-ethnic groups.