Complex genetic nature of sex-independent transmission ratio distortion in Asian rice species: the involvement of unlinked modifiers and sex-specific mechanisms.

Transmission ratio distortion (TRD), in which one allele is transmitted more frequently than the opposite allele, is presumed to act as a driving force in the emergence of a reproductive barrier. TRD acting in a sex-specific manner has been frequently observed in interspecific and intraspecific hybrids across a broad range of organisms. In contrast, sex-independent TRD (siTRD), which results from preferential transmission of one of the two alleles in the heterozygote through both sexes, has been detected in only a few plant species. We previously reported an S(6) locus-mediated siTRD, in which the S(6) allele from an Asian wild rice strain (Oryza rufipogon) was transmitted more frequently than the S(6)(a) allele from an Asian cultivated rice strain (O. sativa) through both male and female gametes in heterozygous plants. Here, we report on the effect of a difference in genetic background on S(6) locus-mediated siTRD, based on the analysis using near-isogenic lines and the original wild strain as a parental strain for crossing. We found that the degree of TRD through the male gametes varied depending on the genetic background of the female (pistil) plants. Despite the occurrence of TRD through both male and female gametes, abnormality was detected in ovules, but not in pollen grains, in the heterozygote. These results suggest the involvement of unlinked modifiers and developmentally distinct, sex-specific genetic mechanisms in S(6) locus-mediated siTRD, raising the possibility that siTRD driven by a single locus may be affected by multiple genetic factors harbored in natural populations.

Association of Lower-Extremity Muscle Performance and Physical Activity Level and Intensity in Middle-Aged and Older Adults: A Doubly Labeled Water and Accelerometer Study.

OBJECTIVES: The purpose of this study was to examine if there is a relationship between lower-extremity muscle performance (LEMP) and physical activity, especially the physical activity level (PAL) value, in community-dwelling middle-aged and older adults. DESIGN: Cross-sectional study. SETTING: Community-based. PARTICIPANTS: Participants were 54 community-dwelling and independent middle-aged and older individuals (aged 54-89 years). MEASUREMENTS: Physical activity level was calculated from the total energy expenditure of each participant obtained using the doubly labeled water method (PALDLW) and estimated basal metabolic rate. Daily step count and intensity of physical activity was monitored with a triaxial accelerometer, and LEMP was assessed using the five-repetition sit-to-stand test (STS-5) and vertical jumping (VJ). RESULTS: The results of STS-5 nearly negatively correlated with those of PALDLW when analysing the middle-aged and older man and woman, separately. VJ positively correlated with PALDLW when analysing the middle-aged and older men and woman, separately. The relationship between LEMP (e.g. STS-5 and VJ) and PAL were maintained, regardless of sex and body composition. PALDLW was significantly positively correlated with LPA, MVPA, and steps, and significantly negatively correlated with sedentary time. The relationship PALDLW and steps was described as following equation: PALDLW = 0.0000392 × steps +1.531. CONCLUSIONS: These findings suggest that PALDLW is a key contributor to increasing LEMP among middle-aged and older adults. Maintaining high PALDLW may be beneficial to independent living, and participation in recreational and social activities in middle-aged and older adults.

Similarity among the Drosophila (6-4)photolyase, a human photolyase homolog, and the DNA photolyase-blue-light photoreceptor family.

Ultraviolet light (UV)-induced DNA damage can be repaired by DNA photolyase in a light-dependent manner. Two types of photolyase are known, one specific for cyclobutane pyrimidine dimers (CPD photolyase) and another specific for pyrimidine (6-4) pyrimidone photoproducts[(6-4)photolyase]. In contrast to the CPD photolyase, which has been detected in a wide variety of organisms, the (6-4)photolyase has been found only in Drosophila melanogaster. In the present study a gene encoding the Drosophila(6-4)photolyase ws cloned, and the deduced amino acid sequence of the product was found to be similar to the CPD photolyase and to the blue-light photoreceptor of plants. A homolog of the Drosophila (6-4)photolyase gene was also cloned from human cells.

Multicenter phase II study of FOLFOX for metastatic colorectal cancer (mCRC) in Japan; SWIFT-1 and 2 study.

BACKGROUND/AIMS: This study assessed the efficacy and toxicity of the FOLFOX4 (SWIFT1) and mFOLFOX6 (SWIFT2) regimens in Japanese patients with metastatic colorectal cancer (mCRC). METHODOLOGY: Patients with mCRC were required to have ECOG performance status of 0 to 1, and to have adequate organ function. Two multicenter Phase II studies (SWIFT1/SWIFT2) were conducted in chemotherapy naive patients with mCRC. RESULTS: 112 patients were enrolled in these studies (SWIFT1: 54 patients / SWIFT2: 58 patients). The disease sites for each study were the colon in 27 patients and 28 patients, and the rectum in 27 patients and 30 patients, respectively. All patients received a median of 8 courses. After a median follow-up period of 35 months, 54 patients and 58 patients were evaluable in the respective studies, and the overall response rate was 50.0% (CR:31 PR:53). The response rate according to the sites of metastasis were as follows: liver, 54.1% (46/85); lung, 17.4% (4/23); and lymph node, 23.3% (7/30). Grade 3/4 neutropenia occurred in 14 patients (12.5%), while Grade 3/4 non-hematological toxicities were observed in 16 patients (31.0%) and Grade 3 neurotoxicity was observed in 6patients (5.4%) and 5 patients (4.5%), respectively. CONCLUSIONS: FOLFOX4 (SWIFT1) and mFOLFOX6 (SWIFT2) regimens complying with the international standard dosage and schedule can also be administered safely and effectively in Japan.

The significance of gastrectomy in advanced gastric cancer patients with non-curative factors.

BACKGROUND: The role of gastrectomy in the treatment of advanced gastric cancer patients with non-curative factors remains controversial. We investigated prognostic factors and evaluated the role of gastrectomy in such patients. PATIENTS AND METHODS: Eighty-eight advanced gastric cancer patients with non-curative factors were prospectively studied. The patients were categorized into the following two groups: Group A: 52 patients who underwent gastrectomy and subsequently received chemotherapy, Group B: 36 patients who received chemotherapy alone. RESULTS: The median survival times of group A and B patients were 351 and 182 days, respectively (p=0.008). Multivariate analysis showed that gastrectomy was the only positive independent prognostic factor, with no effect on the results of chemotherapy. There was no significant difference in the duration of hospital stay between patients of the two groups, while significantly longer maintenance of oral intake was observed for group A. CONCLUSION: In advanced gastric cancer patients with non-curative factors, gastrectomy was beneficial for survival with longer maintenance of oral intake.

Discal cysts of the lumbar spine: a case report.

Discal cysts--intraspinal cysts communicating with an adjacent intervertebral disc--are an uncommon cause of lumbar radiculopathy. We report a case of discal cyst of the lumbar spine. The cyst contents were bloody and clotted rapidly; no disc materials were seen. Communication between the cyst and the intervertebral disc was detected. Histopathology of the cyst wall revealed fibrous connective tissue without synovial lining cells. We hypothesise that the discal cyst was formed by haemorrhage of the epidural venous plexus caused by separation of the peridural membrane by mechanical force transmitted by an annulus fibrosis fissure. The minute segmental motion caused by the affected disc may have stimulated continuous bleeding.

Deletion of 17p and amplification of the int-2 gene in esophageal carcinomas.

We have analyzed allelic deletion at 23 loci on 18 different chromosomes in 35 esophageal squamous cell carcinoma tissues by using restriction fragment length polymorphism markers. Loss of heterozygosity was detected on chromosomes 2, 3, 6, 7, 11-14, 16-18, 21, and 22, while no loss was detected on chromosomes 1, 4, and 8-10. Only the loss of chromosome 17p was detected with high frequency (45%), and losses on other chromosomes had frequencies of less than 22%. These losses with low frequencies might be random losses caused by chromosomal rearrangement during the course of tumor development and progression. On the contrary, the loss of 17p might play an important role in the development of esophageal squamous cell carcinoma, such as inactivation of a tumor suppressor gene. Amplification of the int-2 gene was observed in 39% of the tumors. However, no significant relationship between int-2 amplification and the deletion of any chromosome was detected.

Allelotype analysis of esophageal squamous cell carcinoma.

In previous studies, we have shown that allelic loss on chromosome 17p, on which the p53 gene is located, is very frequent, and loss-of-function mutations of the p53 gene are closely associated with the tumorigenesis of esophageal cancer. In this study, we performed allelotype analysis to investigate whether other tumor suppressor genes are also involved in esophageal cancer. Using 55 polymorphic DNA markers covering every autosomal arm except 13p, 21p, and 22p, restriction fragment length polymorphism analysis was performed on 36 esophageal squamous cell carcinomas (ESCs) and their adjacent normal tissue samples. Frequent loss of heterozygosity (LOH) of > 30% of the informative cases was observed on chromosomes 3p (41.1%), 5q (52.6%), 6p (30.4%), 8p (33.3%), 9p (35.7%), 9q (30.8%), 11p (32.4%), 13q (52.7%), 17p (55.2%), 17q (33.3%), 18q (45.7%), and 19q (30.4%). Among these, LOH on 5q, 13q, 17p, and 18q was previously reported in ESC and is considered to involve the APC, RB, p53, and DCC genes, respectively. However, our deletion analysis of chromosome 18q revealed that the region commonly lost did not include the DCC locus, suggesting that a possible tumor suppressor gene on 18q other than the DCC gene is involved in ESC. We screened 60 primary ESC tumors and 20 cultured ESC cell lines for the mutation of the APC gene within a mutation cluster region in exon 15, where the "hot spot" of somatic mutation for colorectal and pancreatic cancers is thought to be. We could not find any mutation despite the high frequency of LOH on chromosome 5q. We also analyzed the relationship between the clinicopathological data and the allelic loss and found that LOH on chromosomes 6p and 13q was associated with poor prognosis.

Loss of heterozygosity frequently affects chromosome 17q in non-small cell lung cancer.

Although the short arm of chromosome 17, which contains the p53 gene, is frequently affected by loss of heterozygosity (LOH) in lung cancer, little is known about similar changes on the long arm. We found that LOH affected one or more of six loci along chromosome 17 in 59% of 102 informative non-small cell lung cancer (NSCLC) cases. Specifically, the frequency of LOH at 17q was 42%, approaching that at 17p (54%), and two distinct 17q regions were implicated. LOH at D17S4 on 17q was more frequent in adenocarcinomas than in squamous cell carcinomas, whereas squamous cell carcinomas had more LOH at 17p than at 17q, findings that indicate molecular genetic heterogeneity between the major NSCLC subtypes. In addition, LOH at 17q correlated with higher T stages and a significantly worse prognosis. In comparison, 25% of cases had mutations of p53 exons 5-8 but these were not associated with stage or survival. The data suggest that independent of p53, there are important tumor suppressor gene(s) on 17q that may influence NSCLC pathogenesis, progression, and survival.

Chromosomal reorganization for the expression of recessive mutation of retinoblastoma susceptibility gene in the development of osteosarcoma.

Recent evidence indicates that the mutation of retinoblastoma susceptibility (RB) gene is also involved in the development of osteosarcoma. We studied 30 cases of osteosarcoma for the structural anomalies of the RB gene by Southern hybridization analysis with cDNA probes of the RB gene. Thirteen cases (43%) showed structural anomalies of the RB gene. They included the total or partial deletion, or rearrangement of the RB gene; seven with homozygous deletions and six with hemizygous deletions or rearrangements. By the use of restriction fragment length polymorphism fragments as chromosome markers, those seven tumors having homozygous deletions and four of six tumors having hemizygous anomalies showed the loss of heterozygosity at other loci on chromosome 13. Among those tumors with no apparent structural changes of the RB gene, seven cases showed the loss of heterozygosity on chromosome 13, and altogether the loss of heterozygosity by either homozygosity or hemizygosity was found in 18 (64%) of 28 informative cases. The loss of heterozygosity was also found for nine of 10 other chromosomes, of which chromosome 17 showed the highest frequency (77%). The tumors with loss of chromosome 13 alleles also showed additional losses of alleles on other chromosomes, while tumors retaining heterozygosity of chromosome 13 also retained heterozygosity at the informative loci on other chromosomes. Southern hybridization and karyotype analysis in some selected cases suggest that the concerted loss of heterozygosity at multiple loci may be a consequence of the polyploidization-segregation process.

Amplification and overexpression of the cyclin D1 gene in aggressive human hepatocellular carcinoma.

We analyzed the genetic alterations of the cyclin D1 and INT-2 genes in hepatocellular carcinomas (HCCs) from 45 patients. Among these, expression of the cyclin D1 mRNA was also analyzed in 18 of them by Northern blotting. The cyclin D1 gene was amplified 3-16 fold in five HCCs (11%); among these, the INT-2 gene was also amplified 2-10 fold in four HCCs. We analyzed the mRNA of cyclin D1 in four HCCs with gene amplifications, and 6-10 fold overexpressions were detected in all of them. Because the cyclin D1 gene was amplified in patients at an advanced stage of HCC with rapid tumor growth, it appeared to be associated with the aggressive behavior of tumors. Studies on loss of heterozygosity on chromosome 13q, where the retinoblastoma (RB) gene is located, indicated that all HCCs with an amplified cyclin D1 gene retained heterozygosity on chromosome 13q. These results suggest that amplification and overexpression of the cyclin D1 gene result in the rapid growth of a subset of HCC, even though the function of the RB gene is retained.

Assignment of common allele loss in osteosarcoma to the subregion 17p13.

Human osteosarcomas frequently show loss of alleles on chromosome 17 as well as those on chromosome 13 that harbors the retinoblastoma gene, indicating concerted operation of another tumor-suppressing gene on chromosome 17. To assign the affected gene to a defined region of chromosome 17, we performed mitotic recombination/deletion mapping by the use of 10 polymorphic loci on chromosome 17. Of 37 tumors studied, 28 (75.7%) showed loss of heterozygosity on chromosome 17. The affected regions varied among tumors, ranging in extent from a whole chromosome to a distal segment of the short arm. However, allele loss in one region, notably in 17p13 between D17S1 and D17S30, was common to all 28 tumors, suggesting the presence of a tumor-suppressing gene in this defined region.

Loss of 17p, mutation of the p53 gene, and overexpression of p53 protein in esophageal squamous cell carcinomas.

We analyzed mutations of the p53 gene by single-strand conformation polymorphism analysis of polymerase chain reaction products and direct sequencing through all coding exons and exon-intron junctions in 32 cases with esophageal squamous cell carcinoma. Mutations were detected in 15 of 32 (47%) tumor samples, in which G:C to T:A transversions were rather frequent (33%). Previously, we reported deletion of chromosome 17p where the p53 gene is located in 45% of Japanese esophageal squamous cell carcinoma, and here the relationship between mutation of the p53 gene and loss of 17p was analyzed. Mutations were observed in 12 of 16 patients with loss of 17p, whereas only 2 of 11 without loss were positive for mutations, suggesting that mutations of the p53 gene were closely associated with a 17p deletion. Furthermore, we immunohistochemically analyzed the expression of p53 protein in esophageal squamous cell carcinoma tumor tissues using a monoclonal antibody. Five of 6 tumors with missense mutations of the p53 gene were positively stained, while in tumors with nonsense mutations or without mutations of the p53 gene staining was very weak or negative. These results suggest a good correlation between mutations and abnormal expression of the p53 gene.

Respective roles of cyclobutane pyrimidine dimers, (6-4)photoproducts, and minor photoproducts in ultraviolet mutagenesis of repair-deficient xeroderma pigmentosum A cells.

The role of UV light-induced photoproducts in initiating base substitution mutation in human cells was examined by determining the frequency and spectrum of mutation in a supF tRNA gene in a shuttle vector plasmid transfected into DNA repair deficient cells (xeroderma pigmentosum complementation group A). To compare the role of two major UV-induced photoproducts, cis-syn cyclobutane-type pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs), each photoproduct was removed from UV-irradiated plasmid by photoreactivation before transfection. Removal of either CPDs or 6-4PPs by in vitro photoreactivation reduced the mutation frequency while keeping the mutation distribution and the predominance of G:C-A:T transitions as UV-irradiated plasmid without photoreactivation, indicating that both cytosine-containing CPDs and 6-4PPs were premutagenic lesions for G:C-A:T transitions. On the other hand, A:T-G:C transitions were not recovered from plasmids after the removal of 6-4PPs, whereas this type of mutation occurred at a significant level (11%) after the removal of CPDs. Thus, the premutagenic lesions for the A:T-G:C transition are 6-4PPs. Removal of both CPDs and 6-4PPs resulted in the disappearance of mutational hot spots and random distribution of mutation as observed in unirradiated control plasmids. However, the mutational spectrum of photoreactivated plasmids differed significantly from that of unirradiated plasmids. A characteristic feature is a high portion of A:T-T:A transversions (11%) in the photoreactivated plasmid. This mutation is due to nondipyrimidinic "minor" photoproducts, and the mutation spectrum suggests that TA*, the major photoproduct of thymidylyl-(3'-5')-deoxyadenosine, is the premutagenic lesion for this mutation. This is the first report revealing the distinct mutagenic roles of the major UV photoproducts and "minor" photoproducts by the use of (6-4)photolyase.

p53 mutation, murine double minute 2 amplification, and human papillomavirus infection are frequently involved but not associated with each other in esophageal squamous cell carcinoma.

We examined the relationship between p53 mutation, murine double minute 2 (MDM2) gene amplification, and human papillomavirus (HPV) infection in 72 esophageal squamous cell carcinomas. We identified p53 mutations in 29 tumors (40.3%) by PCR-single-strand conformation polymorphism analysis and direct sequencing. Amplification of the MDM2 gene was detected by Southern blot hybridization in 13 (18.1%) of 72 tumor tissues and in 4 (33.3%) of 12 cultured esophageal squamous cell lines. All four cell lines with MDM2 amplifications showed overexpression of the MDM2 mRNA in Northern blotting. We observed HPV infection in 15 (20.8%) of 72 tumor tissues by specific PCR amplification and Southern blot hybridization. In most tumors, amplification of the MDM2 gene or infection of HPV was not associated with p53 mutations, except in four cases with p53 mutation and MDM2 amplification, and three cases with p53 mutation and HPV infection. Since p53 mutations, MDM2 overexpression, and HPV infection are all considered to abrogate the normal function of p53 protein, each of these genetic changes may be equally important in tumorigenesis. In addition, we found that patients with MDM2 amplification exhibited a significantly shorter survival period (P = 0.0053).

Novel and global approach of the complex and interconnected phenomena related to the contact line movement past a solid surface from hydrophobized silica gel.

In this work a generalized hydrodynamic theory for water flow into a mesoporous matrix from hydrophobized silica gel is suggested. Although we examine a fluid dynamics problem, the motion of the water-gas-solid contact line past a hydrophobized silica gel surface, motivation for such research derives from the investigation of a novel principle of mechanical energy dissipation, called surface dissipation, and its attached machine element, named a colloidal damper (CD). Similar to a hydraulic damper, this absorber has a cylinder-piston structure, but oil is replaced by a colloid consisting of a mesoporous matrix and a lyophobic liquid. Here, the mesoporous matrix is from silica gel modified by linear chains of alkyldimethylchlorosilanes and water is the associated lyophobic liquid. Mainly, the colloidal damper energy loss can be explained by the dynamic contact angle hysteresis in advancing (liquid displaces gas) and receding motion (gas displaces liquid); such hysteresis occurs due to the geometrical and chemical heterogeneities of the solid surface. Although this new kind of dissipation could be attractive for many applications, the subject remains almost unexplored in the scientific literature. Many different, complex, and interconnected aspects are related to this subject: capillary hydrodynamics, slippage effect, contact angle hysteresis, estimation of dissipated energy, thickness optimization of the grafted layer on the surface of the mesoporous matrix, etc. For this reason, a novel and global approach to all the complex and interconnected phenomena related to the contact line movement past a solid surface from hydrophobized silica gel is proposed. Our approach has a modest experimental basis but this is compensated for with rich references to other experimental and theoretical work oriented to the study of surface phenomena in such systems. We tried to sort the existing results and to find the right place for each in building our global view of the problem. This work is structured as follows. The measurement technique of the hysteresis loop is described. From experimental data one calculates the dissipated energy versus length of the grafted molecule on the silica gel surface. These results are justified by flow analysis. Generalized hydrodynamic theory means here that the basic structure of the Navier-Stokes equations is kept, but in order to include the relation between macroscopic flow and molecular interactions, slip is allowed on the solid wall. The nanopillar architecture of the silica gel hydrophobic coating is described. Concepts of slip and contact angle hysteresis are detailed and their connection is revealed. During adsorption, water penetrates the pore space by maintaining contact with the top of the coating molecules (region of -CH(3) groups); after that, water is forced into and partially or totally fills the space between molecules (region of -CH(2) groups). In such circumstances, at the release of the external pressure, desorption occurs. An original energetic-barriers approach is proposed to understand the filling of the nanosize canals which occur in the hydrophobic grafted layer. Employing this energetic-barriers approach, one finds the optimum length of the grafted molecule which maximizes the dissipated energy of the CD reversible cycle. Such results are useful for the appropriate design of ultrahydrophobic surfaces in general, and for the optimal design of a hydrophobic coating of a mesoporous matrix destined for CD use.

Somatic mosaicism for DNA repair capacity in fibroblasts derived from a group A xeroderma pigmentosum patient.

A female Japanese xeroderma pigmentosum (XP) patient with severe skin lesions and various neurologic abnormalities was assigned to complementation group A by conventional cell fusion studies. Ultraviolet (UV)-irradiated skin fibroblasts showed a biphasic survival curve, as measured by colony-forming ability. The surviving fraction decreased rapidly up to 2 J/m2 of UV, with a steep slope of D(O) (mean lethal dose) = 0.95 J/m2. At much higher doses it decreased more slowly, with D(O) = 3.5 J/m2. To èlucidate the cause of this unique survival response, we isolated a large number of independent clones from single colonies and measured their responses to UV. Of 81 clones analyzed, ten showed a marked resistance to killing by UV, which was only slightly more sensitive than normal cells, and these clones had a rate of unscheduled DNA synthesis (UDS) that was about 45% of normal cells. By contrast, the remaining 71 clones were extremely sensitive to UV, typical of XP group A strains, and had a UDS level 1%-3% of normals. Analysis of restriction fragment length polymorphism using seven polymorphic DNA probes indicated that the UV-resistant clones were derived from the same individual as the UV-sensitive clones. These results clearly demonstrate that this patient's fibroblast cells consist of two types with differing responses to UV, and provide direct evidence of somatic mosaicism for DNA repair capacity in an XP patient.

Three-dimensional visualization of ultraviolet-induced DNA damage and its repair in human cell nuclei.

The two major forms of DNA damage produced by 254 nm UV light are cyclobutane pyrimidine dimer (CPD) and (6-4) photoproduct (6-4PP). Both photolesions are repaired in normal human cells by nucleotide excision repair; however, little is known about where CPD or 6-4PP are repaired in relation to the various subnuclear structures. This study aimed to produce a three-dimensional demonstration of UV-induced DNA damage and its repair in human cell nuclei. We first investigated the repair kinetics of CPD and 6-4PP using an enzyme-linked immunosorbent assay with damage-specific monoclonal antibodies in normal human and xeroderma pigmentosum complementation group C cells. We also examined the kinetics of repair DNA synthesis (unscheduled DNA synthesis) using a quantitative immunofluorescence method with anti-5-bromo-2'-deoxyuridine antibodies. We confirmed the normal repair in normal human cells and the impaired repair in xeroderma pigmentosum complementation group C cells. Then, using laser scanning confocal microscopy, we succeeded in forming a three-dimensional visualization of the nuclear localization of CPD, 6-4PP, and unscheduled DNA synthesis in individual human cells. The typical three-dimensional images of photolesions or unscheduled DNA synthesis at various repair times reflected the repair kinetics obtained by enzyme-linked immunosorbent assay or immunofluorescence very well. The important finding is that the punctate, not diffusely spread, nuclear localization of unrepaired 6-4PP was found 2 h after irradiation. Similarly, the focal nuclear localization of unscheduled DNA synthesis was observed during both the first and the second 3 h repair periods. The present results suggest that both 6-4PP and CPD are nonrandomly repaired from nuclei in normal human cells.

Enhancement by X-ray irradiation of target cell susceptibility to natural killer cells.

The in vitro effect of X-ray irradiation on tumor cell susceptibility to lysis by natural killer (NK) cells was studied in human systems. When relatively NK-resistant T24 bladder transitional carcinoma cells were irradiated with X-rays and cultured for 18 h, they showed increased sensitivity to lysis by blood lymphocytes in a 4-h 51Cr release assay. No enhancement was seen when irradiated target cells were tested immediately after exposure to X-rays. The X-ray-induced augmentation was observed with as little as 1 Gy of irradiation, the level of which was comparable to that observed at higher doses. The doses of X-rays did not influence the viability and spontaneous release of the target cells. Treatment with mitomycin C of target cells did not change their NK sensitivity. On the other hand, irradiation with X-rays of blood lymphocytes resulted in a transient increase in NK activity at 3 h, and then the activity declined and was completely lost by 24 h. However, when irradiated lymphocytes were stimulated with interferon (IFN), they maintained the high activity against untreated T24 cells. These results suggest the possible use of relatively low doses of X-ray irradiation in combination with IFN for treatment of human cancer.

Expression of second class of KIP protein p57KIP2 in human colorectal carcinoma.

p57KIP2, the second class of KIP family protein, is one of the negative regulators of the cell cycle. To elucidate the role of p57KIP2 in colorectal normal mucosa and cancer, we examined the expression of p57KIP2 protein in 110 pairs of colorectal non-tumor and cancer tissues. Immunohistochemical analysis showed that p57KIP2 was weakly detected in the normal colonic epithelium and lymph follicles. A unique expression pattern of p57KIP2 was exclusively noted in the elastic fibers within the walls of relatively large blood vessels (diameter > 100 microm). In cancer tissues, p57KIP2 protein was localized mainly in nuclei. Using the mean percentage of nuclear p57KIP2 expression (25%) as the cut-off value, we divided our cases into those with high expression (n = 44, 40%) and low expression (n = 66, 60%) of p57KIP2 among 110 colorectal cancer cases tested. The clinical and pathological survey showed a significant correlation between low expression of p57KIP2 and large tumor size (p < 0.05) or the presence of tumors in females (p < 0.01). Survival analysis showed that p57KIP2 expression did not influence prognosis. RT-PCR analysis was also performed using RNA extracts from 6 colorectal cancer tissues. When the levels of p57KIP2 mRNAs were compared with expression of p57KIP2 protein, a clear correlation was found, suggesting that expression of the p57KIP2 protein may be regulated at the transcription level. The present study revealed p57KIP2 expression in colorectal cancer and suggests that p57KIP2 may not play a central role in the progression of colorectal cancer.