[Short-term exposure to gossypol causes reversible reproductive toxicity and nephrotoxicity in mice]

OBJECTIVE

To study the toxic effects of short-term exposure to gossypol on the testis and kidney in mice and whether these effects are reversible.

METHODS

Twenty 7 to 8-week-old male mice were randomized into blank control group, solvent control group, gossypol treatment group and drug withdrawal group. In the former 3 groups, the mice were subjected to daily intragastric administration of 0.3 mL of purified water, 1% sodium carboxymethylcellulose solution, and 30 mg/mL gossypol solution for 14 days, respectively; In the drug withdrawal group, the mice were treated with gossypol solution in the same manner for 14 days followed by treatment with purified water for another 14 days. After the last administration, the mice were euthanized and tissue samples were collected. The testicular tissue was weighed and observed microscopically with HE and PAS staining; the kidney tissue was stained with HE and examined for mitochondrial ATPase activity.

RESULTS

Compared with those in the control group, the mice with gossypol exposure showed reduced testicular seminiferous epithelial cells with rounded seminiferous tubules, enlarged space between the seminiferous tubules, interstitium atrophy of the testis, and incomplete differentiation of the spermatogonia. The gossypol-treated mice also presented with complete, non-elongated spermatids, a large number of cells in the state of round spermatids, and negativity for acrosome PAS reaction; diffuse renal mesangial cell hyperplasia, increased mesangial matrix, and adhesion of the mesangium to the wall of the renal capsule were observed, with significantly shrinkage or even absence of the lumens of the renal capsules and reduced kidney mitochondrial ATPase activity. Compared with the gossypol-treated mice, the mice in the drug withdrawal group showed obvious recovery of morphologies of the testis and the kidney, acrosome PAS reaction and mitochondrial ATPase activity.

CONCLUSIONS

Shortterm treatment with gossypol can cause reproductive toxicity and nephrotoxicity in mice, but these toxic effects can be reversed after drug withdrawal.

The three-dimensional evaluation of positional change in mandibular condyle after intraoral vertical ramus osteotomy

OBJECTIVES

The purpose of this study was to compare the changes of the condylar axis, the anteroposterior condylar position relative to the glenoid fossa, after intraoral vertical ramus osteotomy (IVRO).

STUDY DESIGN

21 patients diagnosed as skeletal class III malocclusion underwent IVRO and were followed according to the authors' postoperative management regimen. The three-dimensional positions of the condyles were evaluated by cone-beam computerized tomography (CBCT) at pre-op, post-op, and at follow-up. CBCT images were referenced to assess the condylar axis change and the anteroposterior condylar position in the glenoid fossa. A repeated-measures analysis of variance (P<0.05) also was performed.

RESULTS

After surgery, both the axial condylar angles and the anteroposterior condylar position were significantly different (P<0.05). The coronal condylar axis rotated outwardly. The anteroposterior condylar position in the glenoid fossa had moved from the concentric to the anterior position. But the condyle changes between post-op and follow-up (P>0.05) were insignificant.

CONCLUSIONS

With postoperative intermaxillary elastic traction, the condyles changed their positions physiologically for newly established jaw movement after IVRO.

Mutation of the rice TCM12 gene encoding 2,3-bisphosphoglycerate-independent phosphoglycerate mutase affects chlorophyll synthesis, photosynthesis and chloroplast development at seedling stage at low temperatures

Glycolysis is a central metabolic pathway that provides energy and products of primary metabolites. 2,3-Biphosphoglycerate-independent phosphoglycerate mutase (iPGAM) is a key enzyme that catalyses the reversible interconversion of 3-phosphoglycerate (3-PGA) to 2-phosphoglycerate (2-PGA) in glycolysis. Low temperature is a common abiotic stress in rice production. However, the mechanism for rice iPGAM genes is not fully understood at low temperature. In this study, the rice mutant tcm12, with chlorosis, malformed chloroplasts and impaired photosynthesis, was grown at a low temperature (<20 °C) to the three-leaf stage, while the normal phenotype at 32 °C was used. Chlorophyll fluorescence analysis and transmission electron microscopy were used to examine features of the tcm12 mutant. The inheritance behaviour and function of TCM12 were then analysed thorough map-based cloning, transgenic complementation and subcellular localisation. The thermo-sensitive chlorosis phenotype was caused by a single nucleotide mutation (T→C) on the fifth exon of TCM12 (LOC_Os12g35040) encoding iPGAM, localised to both nucleus and membranes. In addition, TCM12 was constitutively expressed, and its disruption resulted in down-regulation of some genes associated with chlorophyll biosynthesis and photosynthesis at low temperatures (20 °C). This is the first report of the involvement of rice iPGAM gene in chlorophyll synthesis, photosynthesis and chloroplast development, providing new insights into the mechanisms underlying early growth of rice at low temperatures.

Three-dimensional architectural and structural analysis--a transition in concept and design from Delaire's cephalometric analysis

The aim of this study was to present a systematic sequence for three-dimensional (3D) measurement and cephalometry, provide the norm data for computed tomography-based 3D architectural and structural cephalometric analysis, and validate the 3D data through comparison with Delaire's two-dimensional (2D) lateral cephalometric data for the same Korean adults. 2D and 3D cephalometric analyses were performed for 27 healthy subjects and the measurements of both analyses were then individually and comparatively analyzed. Essential diagnostic tools for 3D cephalometry with modified definitions of the points, planes, and measurements were set up based on a review of the conceptual differences between two and three dimensions. Some 2D and 3D analysis results were similar, though significant differences were found with regard to craniofacial angle (C1-F1), incisal axis angles, cranial base length (C2), and cranial height (C3). The discrepancy in C2 and C3 appeared to be directly related to the magnification of 2D cephalometric images. Considering measurement discrepancies between 2D and 3D Delaire's analyses due to differences in concept and design, 3D architectural and structural analysis needs to be conducted based on norms and a sound 3D basis for the sake of its accurate application and widespread adoption.

Visual pathway-related horizontal reference plane for three-dimensional craniofacial analysis

OBJECTIVES

To construct three-dimensional (3D) horizontal reference planes based on visual pathway and to determine their stability and reliability by analyzing the structural patterns of normal and dysmorphology for 3D craniofacial analysis.

SETTING AND SAMPLE POPULATION

Thirty-six subjects with maxillofacial dysmorphology and malocclusion, and eight normal controls. MATERIALS AND METHODS POPULATION: On the 3D computed tomographic images of the subjects, the visual pathway-based planes, including the orbital axis plane (OAP), visual axis plane (VAP), and the optical axis plane (OpAP), were constructed and evaluated.

RESULTS

The OAP, but not the VAP and OpAP, showed the ideal relationship between the midsagittal and posterior maxillary plane, and properly described the different patterns of maxillofacial dysmorphology with craniofacial plane 1 of Delaire's analysis and the occlusal plane.

CONCLUSIONS

The proposed visual pathway-related horizontal reference planes, and in particular the OAP, seem to correctly express the visual axis and the position of the head in natural head position and can be used as a horizontal reference plane for the 3D analysis of craniofacial dysmorphology and anthropology.

Multiple copies of 16s rRNA gene affect the restriction patterns and DGGE profile as revealed by analysis of genome database

The use of 16S rRNA gene has been a "golden" method to determine the diversity of microbial communities in environmental samples, phylogenetic relationships of prokaryotes and taxonomic position of newly isolated organisms. However due to the presence of multiple heterogeneous 16S rRNA gene copies in many strains, the interpretation of microbial ecology via 16S rRNA sequences is complicated. Purpose of present paper is to demonstrate the extent to which the multiple heterogeneous 16S rRNA gene copies affect RFLP patterns and DGG E profiles by using the genome database. In present genome database, there are 782 bacterial strains in total whose genomes have been completely sequenced and annotated. Among the total strains, 639 strains (82%) possess multiple 16S rRNA gene copies, 415 strains (53%) whose multiple copies are heterogeneous in sequences as revealed by alignment, 236 strains (30%) whose multiple copies show different restrict patterns by CSP61 + Hinfl, MspI + Rsal or HhaI as analyzed in silico. Polymorphisms of the multiple copies in certain strains were further characterized by G + C% and phylogentic distances based on the sequences of V3 region, which are linked to DGGE patters. Polymorphisms of a few strains were shown as examples. Using artificial communities, it is demonstrated that the presence of multiple heterogeneous 16S rRNA gene copies potentially leads to over-estimation of the diversity of a community. It is suggested that care must be taken when interpreting 16S rRNA-based RFLP and DGGE data and profiling an environmental community.

Hyper-methylation of RIZ1 tumor suppressor gene is involved in the early tumorigenesis of hepatocellular carcinoma

The retinoblastoma protein-interacting zinc finger gene RIZ1 is a putative tumor suppressor gene, and the inactivation of the RIZ1 is frequently found in tumors through a loss of mRNA expression. In order to understand the role of RIZ1 inactivation in the tumorigenesis of hepatocellular carcinoma (HCC), we detected the RIZ1 promoter methylation status in 39 HCCs using a methylation specific PCR (MSP) method, and carried out LOH study with marker P704. We also assessed the associations between the methylation status and clinicopathological parameters, tumor size, tumor differentiation, and fractional allelic loss (FAL). The results showed that the RIZ1 promoter methylated both in advanced tumors (>3 cm), (18/31, 58.0%) and in early tumors (<3 cm), (4/8, 50.0%). There were 54.6% (12/22) tumors with hyper-methylation in the low FAL group and 45.5% (10/22) in the high FAL group. Moreover, the DNA methylation of the RIZ1 promoter was found not only in the poorly differentiated tumors (12/22, 54.6%), but also in the well differentiated tumors (10/22, 45.5%). Among the 22 HCCs (22/39, 56.4%) that showed hyper-methylation at the RIZ1 promoter region, 3 cases showed biallelic methylation. Interestingly, one case showed hyper-methylation on one allele and a loss of heterozygosity (LOH) on the other allele. In other words, 4 HCCs showed the biallelic inactivation of the RIZ1. These results suggest that the inactivation of the RIZ1 by DNA methylation at its promoter region is involved in the tumorigenesis of HCC, particularly in the early stage of disease.

Hypermethylation in human cancers of the RIZ1 tumor suppressor gene, a member of a histone/protein methyltransferase superfamily

The retinoblastoma protein-interacting zinc finger gene RIZ1 is a tumor suppressor gene and a member of a nuclear histone/protein methyltransferase superfamily. RIZ1 inactivation is commonly found in many types of human cancers and occurs through loss of mRNA expression, frameshift mutation, chromosomal deletion, and missense mutation. RIZ1 is also a tumor susceptibility gene in mice. We now show that loss of RIZ1 mRNA in human cancers is associated with DNA methylation of its promoter CpG island. Methylation of the RIZ1 promoter strongly correlated with lost or decreased RIZ1 mRNA expression in breast, liver, colon, and lung cancer cell lines as well as in liver cancer tissues. Treatment with the methylation inhibitor 5-aza-2'-deoxycytidine activated RIZ1 mRNA expression in cancer cells. Furthermore, methylation was found in 11 of 25 (44%) breast cancer specimens and 20 of 32 (62%) liver cancer specimens. Our results suggest that DNA methylation is a common mechanism in inactivating the RIZ1 tumor suppressor gene in human liver and breast cancers.

Participation of intracellular Ca(2+)/calmodulin and protein kinase(s) in the pathway of apoptosis induced by a Drosophila cell death gene, reaper

To elucidate the apoptotic signaling pathway, we have generated a cell culture model: S2 cells stably transfected with a Drosophila cell death gene, reaper (rpr). Following rpr overexpression, caspase activation-mediated apoptotic cell death was induced in the cells. Apoptosis triggered by rpr required intracellular Ca(2+) ions and calmodulin. Furthermore, protein kinase inhibitors H-7 (a PKC, PKA, PKG, MLCK, and CKI inhibitor), calphostin C (a PKC inhibitor), or H-89 (a PKA and PKG inhibitor) completely blocked apoptosis induced by rpr, suggesting that some kind of serine/threonine protein kinase(s) act upstream of caspase in apoptotic pathway induced by rpr in S2 cells.

Preferential loss of a polymorphic RIZ allele in human hepatocellular carcinoma

The RIZ (PRDM2) locus commonly undergoes loss of heterozygosity (LOH) and maps within the minimal deleted region on 1p36 in hepatocellular carcinoma (HCC). Although peptide-altering mutations of RIZ are rare in HCC, the RIZ1 product is commonly lost in HCC and has tumour suppressive activities. Here, we analysed RIZ gene mutations and LOH in HCC, breast cancer, familial melanoma, colon cancer, and stomach cancer. We found 7 polymorphisms but no mutations. By analysing the Pro704-deletion polymorphism, we detected LOH of RIZ in 31 of 79 (39%) informative HCC cases, 11 of 47 (23%) colon cancer cases, 8 of 43 (19%) breast cancer cases, 8 of 66 (12%) stomach cancer cases. Importantly, loss of the Pro704(+)allele was found in 74% of the 31 LOH positive HCC cases (P< 0.01), indicating a preferential loss and hence a stronger tumour suppressor role for this allele compared to the P704(-)allele. In addition, the Pro704(+)allele was found to be more common in Asians (0.61) than Caucasians (0.42) (P = 0.0000), suggesting an interesting link between gene polymorphisms and potential differences in tumour incidence between racial groups.

Identification of novel deletion regions on chromosome arms 2q and 6p in breast carcinomas by amplotype analysis

DNA fingerprinting by arbitrarily primed PCR (AP-PCR) was employed to identify molecular genetic alterations in 37 primary breast carcinomas. AP-PCR is a PCR-based technique that uses only one primer of arbitrary sequence that generates a molecular karyotype (amplotype) of tumors. The breast cancer amplotype generated with two arbitrary primers (MCG1 and Blue) showed a relatively high frequency (more than 20% of the tumors) of gains at chromosomes 1, 4, and 8, and of losses at chromosomes 2, 4, 6, 9, 10, 11, 13, and the X chromosome. We further analyzed the regions most commonly gained at chromosome 8 (47%) and lost at chromosomes 2 (38%) and 6 (49%) by determining the subchromosomal localization of the fingerprint bands from these chromosomes. The region of gain at chromosome 8 was mapped at 8q24.1, close to MYC. Band MCG1-A1 was assigned to chromosome band 2q22, and band Blue-J was assigned to 6p21. Common losses of these chromosomal regions have not been described for breast cancer. To map these deletion regions more precisely, we performed loss of heterozygosity (LOH) analysis by microallelotyping on 20 of the 37 cancers previously analyzed by AP-PCR and another additional 52 breast carcinomas. The results suggest that the regions at 2q21-24 and 6p21-23 may harbor novel tumor suppressor genes for breast cancer. LOH at 2q21-24 (D2S2304) was more frequent in high-grade tumors (59%) than in low-grade tumors (29%) (P = 0.03). This suggests that this genetic alteration may be associated with tumor progression and shows the power of the amplotype approach in detecting novel genetic alterations that are useful as clinical parameters of breast cancer.

CDK inhibitors suppress apoptosis induced by chemicals and by excessive expression of a cell death gene, reaper, in Drosophila cells

The present study was aimed to investigate whether or not cyclin-dependent kinases (CDKs) participate in different cascades leading to apoptosis. We examined the effects of two CDK inhibitors, olomoucine (OLM) and butyrolactone-I (BL-I), on apoptosis induced in two kinds of Drosophila cell lines. Increases of caspase activity induced by actinomycin D, cycloheximide, H-7 or A23187 in a Drosophila neuronal cell line, ML-DmBG2-c2, and induced by excessive expression of a Drosophila cell death gene, reaper, in Drosophila S2 cells were suppressed by 24-h pretreatment of each CDK inhibitor. Concomitant with the suppression of the caspase activity, fragmentations of cells and DNA, representatives of apoptosis, were also inhibited. These results suggest that CDK(s) participates in progression of apoptosis. However, these effects of the CDK inhibitors were also observed even at lower doses which did not affect cell proliferation. Therefore, it was shown that apoptosis is not always related to cell cycle in Drosophila cells. It was also suggested that the target(s) of the CDK inhibitors locates upstream of caspase in the cascade(s) of apoptosis.

Mapping of a minimal deleted region in human hepatocellular carcinoma to 1p36.13-p36.23 and mutational analysis of the RIZ (PRDM2) gene localized to the region

Human chromosome band 1p36 commonly undergoes loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC) but the minimal deleted region remains to be mapped. This chromosomal region contains a candidate HCC suppressor gene, RIZ (PRDM2), that is a member of the PR (PRDI-BF1-RIZ homology)-domain-containing zinc finger gene family. One characteristic of this family is the unusual yin-yang involvement in human cancers. The PR-domain-containing RIZ1 product of the RIZ locus, in contrast to the PR-domain-minus product RIZ2, is commonly lost or underexpressed in HCC. Furthermore, RIZ1 can induce cell cycle arrest, apoptosis, or both and suppress HCC tumorigenicity in nude mice. To help identify the putative HCC locus on 1p36 and to evaluate a genetic role of RIZ in HCC, we studied 97 HCC cases and mapped a minimal deleted region in HCC to 1p36.13-p36. 23 between markers D1S434 and D1S436. Notably, RIZ mapped within this region and was found to undergo LOH in 37% (25/67) of HCC cases. Single-strand conformation polymorphism (SSCP) analysis, however, did not show mutations in the PR-domain region of RIZ1 in 49 cases of HCC examined. Our data suggest that the RIZ locus is a target of frequent deletion in HCC, but that the more common way of RIZ inactivation in HCC may not involve mutations that alter peptide sequences. Genes Chromosomes Cancer 28:269-275, 2000.

Mapping of a minimal deleted region in human hepatocellular carcinoma to 1p36.13-p36.23 and mutational analysis of the RIZ (PRDM2) gene localized to the region

Human chromosome band 1p36 commonly undergoes loss of heterozygosity (LOH) in hepatocellular carcinoma (HCC) but the minimal deleted region remains to be mapped. This chromosomal region contains a candidate HCC suppressor gene, RIZ (PRDM2), that is a member of the PR (PRDI-BF1-RIZ homology)-domain-containing zinc finger gene family. One characteristic of this family is the unusual yin-yang involvement in human cancers. The PR-domain-containing RIZ1 product of the RIZ locus, in contrast to the PR-domain-minus product RIZ2, is commonly lost or underexpressed in HCC. Furthermore, RIZ1 can induce cell cycle arrest, apoptosis, or both and suppress HCC tumorigenicity in nude mice. To help identify the putative HCC locus on 1p36 and to evaluate a genetic role of RIZ in HCC, we studied 97 HCC cases and mapped a minimal deleted region in HCC to 1p36.13-p36. 23 between markers D1S434 and D1S436. Notably, RIZ mapped within this region and was found to undergo LOH in 37% (25/67) of HCC cases. Single-strand conformation polymorphism (SSCP) analysis, however, did not show mutations in the PR-domain region of RIZ1 in 49 cases of HCC examined. Our data suggest that the RIZ locus is a target of frequent deletion in HCC, but that the more common way of RIZ inactivation in HCC may not involve mutations that alter peptide sequences. Genes Chromosomes Cancer 28:269-275, 2000.

Frequent chromosomal instability but no microsatellite instability in hepatocellular carcinomas

Microsatellite instability (MSI) phenotype, caused by a deficiency of DNA mismatch repair genes, has been detected in a subset of tumors in the gastrointestinal tract. However, it is not clear how MSI is involved in the tumorigenesis of hepatocellular carcinomas (HCC). Results with HCC are controversial, with positive results published with American and European tumors, but negative with Japanese tumors. We report the absence of MSI in 39 Korean HCCs after analysis with 6 mononucleotide- and over 150 dinucleotide-repeat markers. Only one such dinucleotide-repeat (D2S213) exhibited a reproducible shift in mobility, representing a somatic mutation present in only some of the tumor cells. This may be the result of a spontaneous error of replication due to the intrinsic mutability of these unstable sequences and without any connection to true genomic instability. In support of this interpretation, no frameshift mutations were found at the coding repeats of target genes for the microsatellite mutator phenotype including TGF-betaRII, BAX, hMSH3, and hMSH6. In contrast, we observed frequent allelic losses on chromosomes 4q, 8p, 16q, and 17p by the analysis of dinucleotide repeats (microallelotyping), reflecting a high degree of tumor chromosomal instability, which was significantly associated to the tumor differentiation (p=0.036, Fisher's exact test). These results suggest that, unlike chromosomal instability, widespread MSI plays no role in the development or progression of HCC.

Frequent frameshift mutations of RIZ in sporadic gastrointestinal and endometrial carcinomas with microsatellite instability

Many lines of evidence suggest that the retinoblastoma protein interacting zinc finger gene RIZ is a strong candidate for the tumor suppressor locus on 1p36, a region commonly deleted in many human cancers with chromosomal instability. In addition, a role for RIZ in tumors of the microsatellite instability pathway is suggested by frequent frameshift mutations in hereditary non-polyposis colorectal carcinomas. Here we studied RIZ mutations in sporadic cancers with microsatellite instability. Frameshift mutations in the two coding polyadenosine tracks of RIZ were found in 19 (48%) of 40 gastric carcinomas, 6 (33%) of 18 endometrial carcinomas, 14 (26%) of 51 of colorectal carcinomas, and 7 (54%) of 13 cell lines. Eleven tumor tissues showed biallelic inactivation of RIZ. In contrast, no frameshift mutations were found in 70 microsatellite stable tumors. These results suggest an important role for RIZ in sporadic cancers with microsatellite instability.

p16 is a major inactivation target in hepatocellular carcinoma

BACKGROUND

The p16(INK4A) gene encodes 2 cell cycle regulator proteins, p16 and p14(ARF), by alternative splicing. This genetic locus also contains another cell cycle regulator gene, p15(INK4B), which encodes p15. The inactivation of the p16 protein has been demonstrated in some hepatocellular carcinomas (HCCs); however, the inactivation of the other 2 cell regulator proteins and their inactivation patterns are not well characterized.

METHODS

To characterize the role of the above 3 cell cycle regulator proteins in HCCs, the authors examined the genomic status of the p16(INK4A) and p15(INK4B) genes and their RNA products in 20 HCC tissues and 7 human HCC cell lines. Homozygous deletions in each exon of p16(INK4A) and p15(INK4B) were evaluated by comparative multiplex polymerase chain reaction (PCR), and the methylation status of the p16(INK4A) and p15(INK4B) promoter region was analyzed by methylation specific PCR.

RESULTS

Homozygous deletions were found in 6 of 20 HCCs (30%) and 2 of 7 HCC cell lines (29%). In 20 HCCs, the frequency of homozygous deletions was 20% in exon 1 of p15(INK4B), 20% in exon 2 of p15(INK4B), 10% in exon 1beta of p16(INK4A), 25% in exon 1alpha of p16(INK4A), 15% in exon 2 of p16(INK4A), and 15% in exon 3 of p16(INK4A). The authors found hypermethylation of the p16(INK4A) promoter region in 7 HCCs (35%) and 3 HCC cell lines (43%). The overall frequency of p16 alterations in HCCs, including hypermethylation and homozygous deletions, was 60% (12 of 20 cases). According to reverse transcriptase-PCR analysis, the absence of RNA expression was most frequent in p16 (11 of 20 cases, 55%) and less frequent in p15 (7 of 20 cases, 35%) and p14(ARF) (5 of 20 cases, 25%).

CONCLUSIONS

Among the 3 cell cycle regulator proteins encoded at the 9p21 genetic locus, inactivation of p16 is the most frequent event in HCCs in which promoter hypermethylation and homozygous deletions are the common mechanisms.

p16 is a major inactivation target in hepatocellular carcinoma

BACKGROUND

The p16(INK4A) gene encodes 2 cell cycle regulator proteins, p16 and p14(ARF), by alternative splicing. This genetic locus also contains another cell cycle regulator gene, p15(INK4B), which encodes p15. The inactivation of the p16 protein has been demonstrated in some hepatocellular carcinomas (HCCs); however, the inactivation of the other 2 cell regulator proteins and their inactivation patterns are not well characterized.

METHODS

To characterize the role of the above 3 cell cycle regulator proteins in HCCs, the authors examined the genomic status of the p16(INK4A) and p15(INK4B) genes and their RNA products in 20 HCC tissues and 7 human HCC cell lines. Homozygous deletions in each exon of p16(INK4A) and p15(INK4B) were evaluated by comparative multiplex polymerase chain reaction (PCR), and the methylation status of the p16(INK4A) and p15(INK4B) promoter region was analyzed by methylation specific PCR.

RESULTS

Homozygous deletions were found in 6 of 20 HCCs (30%) and 2 of 7 HCC cell lines (29%). In 20 HCCs, the frequency of homozygous deletions was 20% in exon 1 of p15(INK4B), 20% in exon 2 of p15(INK4B), 10% in exon 1beta of p16(INK4A), 25% in exon 1alpha of p16(INK4A), 15% in exon 2 of p16(INK4A), and 15% in exon 3 of p16(INK4A). The authors found hypermethylation of the p16(INK4A) promoter region in 7 HCCs (35%) and 3 HCC cell lines (43%). The overall frequency of p16 alterations in HCCs, including hypermethylation and homozygous deletions, was 60% (12 of 20 cases). According to reverse transcriptase-PCR analysis, the absence of RNA expression was most frequent in p16 (11 of 20 cases, 55%) and less frequent in p15 (7 of 20 cases, 35%) and p14(ARF) (5 of 20 cases, 25%).

CONCLUSIONS

Among the 3 cell cycle regulator proteins encoded at the 9p21 genetic locus, inactivation of p16 is the most frequent event in HCCs in which promoter hypermethylation and homozygous deletions are the common mechanisms.

Deletion mapping of chromosome 16q in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) frequently shows an allelic imbalance (AI) on chromosome 16q. In order to define the commonly affected regions on chromosome 16q, we assessed AI studies in 41 HCCs using a panel of 37 microsatellite markers. Thirty-five cases (85%) showed AI at one or more loci. Among the 35 cases with AI, 21 cases showed multiple AI, suggesting the wide scope of deletion on the long arm of chromosome 16, and the remaining 14 cases showed partial AI. Detailed deletion mapping identified two independent commonly deleted regions on this chromosome arm. These included the D16S3106 locus and D16S498 locus. In conclusion, we have demonstrated frequent AI on 16q in HCCs and identified two loci with frequent AI, which may harbour new tumour suppressor genes.

Deletion mapping on the short arm of chromosome 8 in hepatocellular carcinoma

To define the commonly deleted region on chromosome 8p for further positional cloning of the putative tumor suppressor gene, we carried out allelic imbalance (AI) studies in 41 HCCs using a panel of 37 microsatellite markers. The overall AI on 8p was 87.8% (36 of 41). Among the 36 cases with AI, 13 cases showed AI in all of the loci, suggesting entire deletion on the short arm of chromosome 8, while the remaining 23 cases showed partial AI. Detailed deletion mapping identified two independent commonly deleted regions on chromosome 8p. These were as follows: (1) centered by the D8S1819 and D8S1706 loci between the D8S561 and D8S1825 loci, (2) centered by the D8S1733 locus between the D8S298 and D8S1739 loci. These results suggest that the two putative tumor suppressor genes may be present on chromosome 8p.

[The effect of inhaled nitric oxide and helium-oxygen mixture on the pulmonary function of asthmatics]

OBJECTIVE

To investigate the effect of inhaled nitric oxide (NO) combined with helium-oxygen mixture on the pulmonary function of asthmatics.

METHODS

18 asthmatic patients were included in this study. The patients were divided into two groups randomly. One group of patients inhaled 100 ppm NO combined with helium-oxygen mixture, the other group inhaled 40 ppm NO-containing helium-oxygen mixture. Pulmonary function was examined intermittently during the study process and compared with that of the patients treated with salbutamol.

RESULTS

It is shown that inhalation of helium-oxygen mixture improved the forced vital capacity, forced expiratory volume during the first 1.0 second (FEV(1)), peak expiratory flow rate (PEFR) and maximal midexpiratory flow rate (MMEF) significantly as compared with inhalation of air. Although salbutamol inhalation improved FEV(1) and MMEF, the effect was weaker than helium-oxygen mixture inhalation. However the effect of helium-oxygen mixture lasted only one minute. Inhalation of 100 ppm NO with helium-oxygen mixture only slightly improved FEV(1) and PEFR as compared with inhalation of helium-oxygen mixture. 40 ppm NO with helium-oxygen mixture did not influence the pulmonary function in the asthmatic patient as compared with helium-oxygen mixture alone.

CONCLUSION

It is suggested that inhalation of helium-oxygen mixture can improve the pulmonary function of asthmatic patients significantly. However, inhalation of NO exerts a weak bronchodilatory effect.

Deletion mapping of chromosome 4q in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) frequently shows a loss of heterozygosity (LOH) on chromosome 4q. In order to define the commonly affected region on chromosome 4q for further positional cloning of the putative tumor suppressor gene, we carried out allelic imbalance (AI) studies in 41 HCCs using a panel of 43 microsatellite markers. Thirty-four cases (82.9%) showed AI at one or more loci. Detailed deletion mapping identified 7 independent, frequently deleted regions on this chromosome arm. These were the (1) D4S1615 locus, (2) D4S1598 locus, (3) D4S620 locus, (4) D4S1566 and D4S2979 loci, (5) D4S1617 and D4S1545 loci, (6)D4S1537 locus; and (7) from the D4S2920 to D4S2954 locus. Among these 7 frequently deleted regions, 5 were associated with tumor differentiation. Our results suggest that several putative tumor suppressor genes may be present on chromosome 4q and that the AI of chromosome 4q may play a role in the aggressive progression of HCC.

Deletion mapping of chromosome 4q in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) frequently shows a loss of heterozygosity (LOH) on chromosome 4q. In order to define the commonly affected region on chromosome 4q for further positional cloning of the putative tumor suppressor gene, we carried out allelic imbalance (AI) studies in 41 HCCs using a panel of 43 microsatellite markers. Thirty-four cases (82.9%) showed AI at one or more loci. Detailed deletion mapping identified 7 independent, frequently deleted regions on this chromosome arm. These were the (1) D4S1615 locus, (2) D4S1598 locus, (3) D4S620 locus, (4) D4S1566 and D4S2979 loci, (5) D4S1617 and D4S1545 loci, (6)D4S1537 locus; and (7) from the D4S2920 to D4S2954 locus. Among these 7 frequently deleted regions, 5 were associated with tumor differentiation. Our results suggest that several putative tumor suppressor genes may be present on chromosome 4q and that the AI of chromosome 4q may play a role in the aggressive progression of HCC.

Clinical significance of clonality in thyroid nodules

BACKGROUND

Many different neoplastic and hyperplastic thyroid diseases present with clinically apparent thyroid nodules. Clonality analysis indicates whether a nodule arises from the polyclonal proliferation of a group of cells or forms a clone from a genetically altered cell and thus provides objective information on the origin of the thyroid nodules. Clonality was studied in thyroid nodules using the polymerase chain reaction (PCR) assay in the X-linked human androgen receptor (HUMARA) gene by random X chromosome inactivation in women.

METHODS

DNA samples were obtained from 28 nodules in 21 women. All nodules and non-tumour thyroid tissues were fractioned selectively under a cryostat. Genomic DNA was isolated and digested with HhaI. PCR amplification of the HUMARA locus was performed using PCR mixtures containing [alpha-32P]2'-deoxycytidine 5'-triphosphate. The PCR products were analysed by denaturing gel electrophoresis.

RESULTS

The HUMARA alleles were heterogeneous in 18 of 21 patients. Among the 23 nodules from 18 patients, all of the eight papillary thyroid carcinomas were monoclonal. Two solitary nodules from follicular adenomas were monoclonal. Of the 13 follicular nodules from nodular goitres, ten were polyclonal and three were monoclonal. The monoclonal follicular nodules were larger in size (3.5 versus 2.0 cm, P< 0.05) and had a tendency towards more cystic changes than polyclonal nodules.

CONCLUSION

PCR-based clonality study of thyroid nodules may help to distinguish hyperplastic from neoplastic nodules.

[Change of pulmonary diffusing capacity, membrane diffusing capacity and pulmonary capillary blood volume in patients with COPD and connective tissue disease at rest and post-exercise]

OBJECTIVE

Studying the changes of pulmonary diffusing capacity (DL), alveolar capillary membrane diffusing capacity (Dm) and pulmonary capillary blood volume (Vc) in patients with COPD and connective tissue disease (CTD) at rest and post-exercise; evaluating the diagnostic values of DL, Dm and Vc in early stage of pulmonary involvement of CTD.

METHOD

Spirometry was performed in the sit position. Several measurements of diffusing capacity of the lung for carbon monoxide (DLCO) were measured by single-breath method at increasing alveolar oxygen tension. The estimations of Dm and Vc were done by the method of Roughton and Forster.

RESULT

(1) In COPD group, the values of DL were lower than that of the control group at rest. The decreases were due to the reduction of Dm, but Vc were normal. In CTD group, all the value of DL, Dm and Vc were lower than that of its control group at rest. (2) COPD patients had the higher DL, Dm and Vc after the end of exercise than that of at rest. But the changes of DL Dm and Vc in COPD patients were lower compared with the control group. In contrast to the control group, DL, Dm and Vc did not increase or even decreased after the end of exercise in CTD group. (3) There was no significant differences of DL, Dm and Vc between the 7 CTD patients with normal pulmonary volume and DLCO and the control subjects at rest. But after the end of exercise, DL, Dm and Vc of CTD patients kept unchanging or even decreasing. The difference between CTD patients and its control group was found significant.

CONCLUSION

The measurements of post-exercise Dm and Vc are sensitive tests for pulmonary involvement in of CTD patients. The results are abmormal much earlier in subject with minimal dyspnea and roentgenologic change. They are useful tests for early stage CTD.

Expression of hMSH2 and hMLH1 in colorectal carcinomas with microsatellite instability

Microsatellite instability (MIN) due to defective mismatch repair (MMR) genes has been reported in a subset of sporadic colorectal carcinomas and in the majority of tumors from patients with hereditary nonpolyposis colorectal cancer (HNPCC) syndrome. Among the known MMR genes, hMSH2 and hMLH1 genes are known to be predominantly altered in HNPCC patients and MIN-positive tumors. In this study, we examined MIN and the protein expression pattern of the hMSH2 and hMLH1 by Western blot and immunohistochemistry from 32 sporadic colorectal carcinomas. MIN was observed in 6 (18%) colorectal carcinomas. Of the 6 MIN-positive tumors, one case showed no expression of either protein, 3 cases showed an absence of hMSH2 protein expression, one case showed an absence of hMLH1 protein expression and one case showed no altered expression of either protein by immunohistochemistry. The decreased expression of the hMSH2 protein in a tumor compared to the normal mucosa was also observed in 5 of the 6 MIN-positive cases by Western blot analysis. All of the MIN-negative tumors showed expression of both proteins by immunohistochemistry. Thus most of the MIN-positive tumors appear to be directly related to the altered expression of these two genes and can be diagnosed by the examination of protein expression.

Allelotype analysis of hepatocellular carcinoma

To elucidate the genetic events which may play important roles in hepatocarcinogenesis, we examined every non-acrocentric chromosome arm of 22 hepatocellular carcinomas (HCCs) for loss of heterozygosity (LOH) using 68 highly polymorphic microsatellite markers. Thirty-six (92%) of 39 chromosome arms showed LOH in at least one patient, however 3 chromosome arms, 2p, 2q, and 20q, did not show any LOH. High to moderate frequency of LOH (> 30% of informative cases) was observed at chromosomes 1q (68.1%), 4q (72.7%), 8p (63.6%), 8q (77.3%), 10q (33.3%), 13q (40%), 14q (46.1%), 16q (59.1%), and 17p (46.2%). Among these, LOH on chromosomes 1q and 8q have not been previously identified in HCC. Our results suggest that novel tumor suppressor genes may be involved in the development and progression of HCC.

Homozygous deletions of the CDKN2 gene and loss of heterozygosity of 9p in primary hepatocellular carcinoma

To elucidate the alterations of CDKN2 in hepatocarcinogenesis, we performed a loss of heterozygosity (LOH) study using eight polymorphic markers surrounding the CDKN2 gene and analyzed the homozygous deletions and mutations of the CDKN2 gene in 41 primary hepatocellular carcinomas (HCCs). Frequent LOH (27.8-44%) was found in the eight loci on chromosome 9p, however, no intragenic mutations of CDKN2 were observed by PCR-SSCP analysis. Homozygous deletions were detected in 25 of 41 HCCs (61%) by a comparative multiplex PCR. No expression of the CDKN2 protein was noted in five out of nine available HCCs by Western blot analysis. These results suggest that inactivation of the CDKN2 gene in HCC is a frequent event in which homozygous deletions are the most common mechanism of CDKN2 inactivation.

Allelotype analysis of hepatocellular carcinoma

To elucidate the genetic events which may play important roles in hepatocarcinogenesis, we examined every non-acrocentric chromosome arm of 22 hepatocellular carcinomas (HCCs) for loss of heterozygosity (LOH) using 68 highly polymorphic microsatellite markers. Thirty-six (92%) of 39 chromosome arms showed LOH in at least one patient, however 3 chromosome arms, 2p, 2q, and 20q, did not show any LOH. High to moderate frequency of LOH (> 30% of informative cases) was observed at chromosomes 1q (68.1%), 4q (72.7%), 8p (63.6%), 8q (77.3%), 10q (33.3%), 13q (40%), 14q (46.1%), 16q (59.1%), and 17p (46.2%). Among these, LOH on chromosomes 1q and 8q have not been previously identified in HCC. Our results suggest that novel tumor suppressor genes may be involved in the development and progression of HCC.

Deletion of the M6P/IGF2r gene in primary hepatocellular carcinoma

To evaluate the different alteration patterns of the mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2r) gene in hepatocellular carcinoma (HCC), 41 HCCs were screened for homozygous deletion and loss of heterozygosity (LOH) at the M6P/IGF2r gene with a dinucleotide repeat polymorphic marker. Of these, three (8.8%) were heterozygous and LOH was observed in two (66.7%) of these informative cases. Five (14.7%) out of 34 informative cases showed homozygous deletions for the dinucleotide repeat polymorphic marker. The frequent allelic loss and homozygous deletion of the M6P/ IGF2r gene suggest that the M6P/IGF2r gene functions as a tumor suppressor gene in the development of HCC.

Relationship between loss of heterozygosity of tumor suppressor genes and histologic differentiation in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common human tumors in Asia and Africa. The molecular genetic changes involving both protooncogenes and tumor suppressor genes are known to be involved in hepatocarcinogenesis, but the roles of the known tumor suppressor genes in hepatocarcinogenesis are not fully elucidated. In this study, the authors analyzed the loss of heterozygosity (LOH) of known tumor suppressor genes in HCC and evaluated the relationship between LOH of tumor suppressor genes and clinicopathologic features.

METHODS

The authors assessed the LOH of the 10 known tumor suppressor genes (VHL, APC, EXT1, WT1, Rb1, p53, BRCA1, nm23, DPC4, and DCC) with microsatellite markers in 29 consecutively resected HCC specimens.

RESULTS

The authors found frequent LOH of tumor suppressor genes in HCC. Twenty five of 29 cases (86%) had LOH of tumor suppressor genes and 17 cases (59%) had LOHs involving 2-4 tumor suppressor genes. Among the tumor suppressor genes, frequent LOH was noted in the p53 (66%), Rb1 (33%), EXT1 (33%), and APC (20%) genes. LOH of the p53 gene and multiple LOH of the tumor suppressor genes were more frequent in poorly differentiated HCCs (P = 0.02).

CONCLUSIONS

The LOH of tumor suppressor genes is frequent in HCCs and LOH of the p53 gene and accumulated LOHs are related to poorly differentiated HCC. Abnormalities of the p53 gene or the accumulated abnormalities of the tumor suppressor genes may play a role in the aggressive progression of HCC.

Clonality of large regenerative nodules in liver cirrhosis

The role of the large regenerative nodule (RN) in hepatocarcinogenesis is not clear, although the incidence of hepatocellular carcinoma (HCC) is high in cirrhotic liver. This study was aimed at clarifying the preneoplastic nature of large RN without atypia. We analyzed the clonality of HCCs and large RNs, ranging in size from 0.6 to 1.2 cm, of cirrhotic liver by X-linked human androgen receptor (HUMARA) gene assay, using the principle of random X chromosome methylation and inactivation in females. Eleven cases of HCC and five cases of large RN without atypia from ten female patients were selected. All HCCs, large RNs and paired non-tumorous tissue from adjacent liver were selectively microdissected from deparaffinized hematoxylin and eosin stained slides. Genomic DNA was isolated and digested with Hha I. Polymerase chain reaction (PCR) amplification of the HUMARA gene was performed using a PCR mixture containing [alpha-32P]-dCTP. The PCR products were separated by gel electrophoresis and analysed by autoradiography. HUMARA was informative in nine out of ten female patients. In the informative 10 HCCs from nine patients, 9 HCCs were monoclonal and one case was polyclonal. The HCC case that showed polyclonality contained many inflammatory cells in the tumor. All of the large RNs were polyclonal. No allelic loss of chromosome 18q was present in the large RNs in constrast to the 3 out of 7 HCCs, which showed allelic deletion in chromosome 18q. We conclude that all or most of the cells composing the large RNs without atypia are polyclonal and the size of a nodule may not be important in hepatocarcinogenesis. This clonality assay may be informative for the differentiation between regenerative and preneoplastic nodules in cirrhotic liver.

Relationship between microsatellite instability and histologic types of colorectal carcinoma

To evaluate the relationship between microsatellite instability (MIN) and histologic types of carcinomas in different organs, we analyzed how often MIN occurred in signet ring cell carcinomas of the colon (7 cases), stomach (13 cases), urinary bladder (5 cases), and prostate (3 cases). We also analyzed MIN and the expression of Epstein-Barr virus encoded RNA (EBER) transcripts in undifferentiated carcinoma with lymphoid stroma: 18 cases of lymphoepithelioma-like carcinoma (LELC) of the colorectum and 8 of the stomach and 9 cases of lymphoepithelial nasopharyngeal carcinoma (NPC). MIN was frequently observed in the signet ring cell carcinomas (4/7, 57%) and LELCs (12/18, 67%) of the colorectum, but was not found in the signer ring cell carcinomas of the urinary bladder or prostate or in NPCs and occurred significantly (p<0.05) less often in both gastric signer ring cell carcinoma (1/13, 8%) and gastric LELCs (1/8, 13%). Most of the gastric LELCs (5/6) and all of the NPCs in which MIN was not identified expressed EBER transcripts. Thus, MIN appear to be specific for signer ring cell carcinomas and LELCs of the colorectum, but there was no strong correlation between MIN and carcinomas in other organs. Different genetic alterations in the different organs could result in the formation of carcinomas of similar types.