Formation of NV centers in diamond by a femtosecond laser single pulse.

The NV centers in a diamond were successfully created by the femtosecond laser single pulse. We also investigated the effect on the diamond lattice induced by the different laser pulse widths from both experimental and theoretical perspectives. Interestingly, in spite of the high thermal conductivity of a diamond, we found that there is a suitable pulse repetition rate of several tens kHz for the formation of NV center ensembles by the femtosecond laser pulse irradiation.

Hepatotoxicity, nephrotoxicity, and drug/chemical interaction toxicity of platinum nanoparticles in mice.

Nanomaterials are frequently used in microelectronics, cosmetics, and sunscreens. Platinum reagents are commonly used in disease diagnosis, cosmetics, and the food industry. Although research into the development of nanomaterialbased drug delivery systems has yielded promising results, the toxicity of these materials is not fully understood. We investigated the toxicity and drug interactions of 1- and 8-nm diameter platinum nanoparticles (nPt1 and nPt8, respectively) in mice. Acute hepato-renal toxicity of intravenously administered platinum nanoparticles was evaluated biochemically and histologically. Dose-dependent increases in serum markers of hepato-renal function (serum aminotransferases and blood urea nitrogen) were observed following administration of nPt1, whereas nPt8 had no effect, even at 20 mg/kg. Moreover, nPt1 induced interleukin (IL)-6 and IL-1ß production 3 and 6 hours after administration. The effect of nPts on drug-induced toxicity was evaluated in mice injected intraperitoneally with carbon tetrachloride or cisplatin, with or without intravenous administration of platinum nanoparticles. All treatments in the absence of nanoparticles were non-lethal and resulted in moderate toxicity. However, exacerbated toxicity was observed in mice injected with carbon tetrachloride or cisplatin together with nPt1, but not in mice co-injected with nPt8. We found that nPt1 cause hepato-renal damage, and the effect is enhanced by chemical inducers of hepatotoxicity and nephrotoxicity. This is the first report demonstrating that nPt1 not only are hepatotoxic and nephrotoxic but also exacerbate drug toxicity. These findings will be useful for future nanotechnology and nanoscience research.

Somatic mutations of the adenomatous polyposis coli gene in gastroduodenal tumors from patients with familial adenomatous polyposis.

We analyzed somatic mutations of the adenomatous polyposis coli (APC), p53, and K-ras genes in gastroduodenal polyps and normal gastroduodenal mucosa from 21 familial adenomatous polyposis patients, using PCR-single-strand conformation polymorphism and direct sequencing methods. Seventy-five polyps were obtained from these patients endoscopically or surgically, and they were histopathologically diagnosed as mild adenoma, moderate adenoma, severe adenoma, adenocarcinoma, and fundic gland polyp. Examining the APC-coding region where somatic mutations in colorectal tumors are known to be clustered, we detected 47 somatic mutations. The frequency of mutation detected was 6 of 9 (67%) in ampullary adenomas, 1 of 2 (50%) in ampullary adenocarcinoma, 11 of 24 (46%) in non-ampullary adenomas, 26 of 29 (90%) in gastric adenomas, and 3 of 11 (27%) in gastric fundic gland polyps. These mutations frequently occurred at codons 1450, 1462-1465, and 1554-1556, the third being a newly found hot spot. All mutations formed stop codons that resulted in truncated APC proteins. K-ras mutation was detected only in an ampullary adenocarcinoma, and p53 mutation was not detected in any of the tumors analyzed. There was no somatic mutation detected in samples of flat mucosa that were diagnosed as normal mucosa both endoscopically and histopathologically. Frequent APC mutations in mild and small adenomas, similar to the findings in severe and large adenomas, suggested that the genetic change in the APC gene occurs in an early stage of forming gastroduodenal adenomas. Moreover, the presence of somatic APC mutations in fundic gland polyps suggests that inactivation of the APC gene plays a role not only in forming adenomas but also in forming hyperplastic polyps in fundic gland mucosa, and there may be some additional steps to the adenoma-carcinoma sequence.

Loss of expression of the DCC gene during progression of colorectal carcinomas in familial adenomatous polyposis and non-familial adenomatous polyposis patients.

We have previously observed that the frequency of loss of heterozygosity (LOH) on chromosome 18q was low in adenomas and intramucosal carcinomas, whereas invasive carcinomas exhibited a high frequency in familial adenomatous polyposis patients (M. Miyaki et al., Cancer Res., 50: 7166-7173, 1990). In the present study, LOH at the DCC locus on chromosome 18q and the expression of DCC gene into mRNA were analyzed in colorectal tumors with distinct histopathological types. The carcinomas that showed 18q LOH also lost the DCC locus. The expression of DCC gene into mRNA was examined at the level of 233-base pair fragments of nucleotide 986-1218 in DCC complementary DNA. In a moderate-to-severe adenoma, 5 carcinoma-in-adenomas, and 4 intramucosal carcinomas, the level of expression was as high as in normal colorectal mucosa, whereas it was greatly reduced or not detectable in most (13 of 16) invasive carcinomas. Among these invasive carcinomas, 7 of 11 showed 18q LOH, but 4 showed no LOH. These results suggest that the DCC gene is included in the allelic deletion on chromosome 18q, and that the progression of colorectal carcinoma from early stage to advanced stage accompanies the inactivation of the DCC gene through LOH and other mechanisms.

Microsatellite instability in the progression of gastric carcinoma.

Seventy-six gastric carcinomas were analyzed with regard to whether or how microsatellite instability was associated with the development of the carcinoma. Microsatellite instability occurred as a late genetic alteration, with an incidence significantly higher in the advanced stage (17 of 51) than in the early stage (3 of 25; P < 0.05). Chromosomal losses on 5q and 17p, detected by polymerase chain reaction-restriction fragment length polymorphism, more frequently accompanied microsatellite instability (9 of 15 and 8 of 11, respectively), compared with carcinomas which lacked instability (5 of 28 and 9 of 30, respectively; P < 0.01 and P < 0.05, respectively). Epstein-Barr virus was observed in only 8 of 76 carcinomas, none of which was associated with microsatellite instability. No significant correlation was found between instability and the familial tendency to develop gastric carcinomas. Our results suggest that microsatellite instability might play a role in the progression of gastric carcinomas but not in Epstein-Barr virus-associated gastric carcinomas.

Coexistence of somatic and germ-line mutations of APC gene in desmoid tumors from patients with familial adenomatous polyposis.

Desmoid tumors, which are locally invasive with recurrence but without metastasis, are frequently observed in patients with familial adenomatous polyposis after abdominal surgery or during pregnancy. This study analyzed mutation of the adenomatous polyposis coli gene in 8 desmoid tumors from 7 familial adenomatous polyposis patients using polymerase chain reaction-single-strand conformation polymorphism and the direct sequencing method. Seven somatic mutations, 1 somatic allele loss, and 6 germ-line mutations were detected. The majority of adenomatous polyposis coli gene mutations were deletions of 1 to 19 base pairs in exon 15, and all mutations led to the formation of stop codons. A somatic mutation with repetition of 82 base pairs from codon 1399 to 1426 was also observed in a desmoid, which was most likely caused by an error during replication or repair replication. No mutation was detected in exons 1 to 2 of H-ras, K-ras, and N-ras genes and in exons 5 to 8 of p53 gene, in these tumors. The simultaneous existence of somatic and germ-line alterations of adenomatous polyposis coli gene observed in all 8 tumors strongly suggests that inactivation of both alleles of adenomatous polyposis coli gene is involved in the development of desmoid tumors.

Genetic changes of both p53 alleles associated with the conversion from colorectal adenoma to early carcinoma in familial adenomatous polyposis and non-familial adenomatous polyposis patients.

Mutation and loss of heterozygosity (LOH) in the p53 gene were analyzed in 274 colorectal tumors of 4 histopathological grades. Among 160 tumors from 40 familial adenomatous polyposis patients, none of 58 adenomas with moderate dysplasia had p53 mutations, whereas 8% (3 of 37) of severe adenomas, 15% (6 of 40) of intramucosal carcinomas, and 40% (10 of 25) of invasive carcinomas had p53 mutations. Only 3% (1 of 33) of severe adenomas showed both mutation and LOH, while 25% (6 of 24) of intramucosal carcinomas and 40% (10 of 25) of invasive carcinomas had both mutation and LOH. All intramucosal and invasive carcinomas that had mutations lost the other allele of the p53 gene. In 114 tumors from 86 non-familial adenomatous polyposis patients, similar results were obtained; no adenoma showed both mutation and LOH, but both alterations occurred in intramucosal and invasive carcinoma. As regards specificity in 56 mutations detected in the present study, the frequently affected codons were codons 175, 238, 245, 248, 273, and 282, 4 of these amino acids being arginine, and 72% (39 of 54) of all mutations were GC to AT transition. Although expression into p53 polyadenylated RNA was high in every invasive carcinoma irrespective of the presence of mutation or LOH, there was a correlation between mutation and protein level; immunostaining of p53 protein was negative in almost all adenomas, but it was positive in 86% of invasive carcinomas exhibiting p53 mutation. These data suggest that genetic changes on both alleles of the p53 gene through mutation and LOH, which result in abnormal protein accumulation, are involved in the conversion of adenoma to early carcinoma. Also, carcinoma cells with p53 mutations existing within adenoma tissues are detectable by immunostaining, even in formalin-fixed, paraffin-embedded specimens.

Characteristics of somatic mutation of the adenomatous polyposis coli gene in colorectal tumors.

Mutation of the adenomatous polyposis coli (APC) gene was analyzed in 500 colorectal tumors from 70 familial adenomatous polyposis (FAP) and 102 non-FAP patients and in normal tissues from 119 FAP patients, using polymerase chain reaction-single-strand conformation polymorphism and direct sequencing methods. These tumors were histopathologically diagnosed. Sixty-eight germ line mutations (62% deletion, 9% insertion, and 29% single-base substitution) and 241 somatic mutations (56% deletion, 12% insertion, and 32% single-base substitution) were detected. All mutations formed stop codons resulting in truncated APC proteins, except for one germ line mutation. Differences were found between somatic and germ line mutations, including 3 new hot spots of mutation at codons 1378, 1450, and 1487-1490, which frequently occurred in somatic mutations but not in germ lines. The frequency of mutation in each histopathological type of FAP tumor was 53% in moderate adenoma, 64% in severe adenoma, 52% in intramucosal carcinoma, and 33% in invasive carcinoma, whereas the loss of heterozygosity including the APC gene increased with development to each histopathological type. A similar tendency was observed in non-FAP tumors. Additionally, we found 10 FAP tumors that had both somatic mutation and loss of heterozygosity. These tumors were assumed to have developed from moderate adenomas with germ line and somatic mutations, followed by deletion of the allele with germ line mutation. These results suggest that inactivation of the APC gene by two mutations is involved in the development of moderate adenoma, and loss of heterozygosity of the APC gene is associated with further development to carcinoma. It was also observed that the distribution of 75 somatic mutations from one FAP patient on the APC sequence was similar to the distribution of 159 somatic mutations from 83 patients with FAP and non-FAP, which suggests that the position of somatic mutation is mostly due to the APC sequence itself.

Suppression of tumourigenicity in human colon carcinoma cells by introduction of normal chromosome 1p36 region.

Development of colon carcinomas appears to be associated with inactivation of multiple tumour suppressor genes. Cytogenetic and DNA analyses of colon carcinomas have detected a high frequency of chromosome 1p deletion, which suggests the presence of a tumour suppressor gene. We therefore introduced normal human chromosome 1 into colon carcinoma COKFu cells, through microcell hybridization. Six clones of hybrid cells containing normal chromosome 1 were obtained, four of which had a small fragment of the introduced chromosome 1, including 1p36-34. The morphology of hybrid cells with chromosome 1 markedly altered to a flat shape. The cloning efficiency of all six hybrid cells in soft agar was significantly reduced, and the tumourigenicity in athymic nude mice was completely suppressed. Hybrid cells containing only the region of 1p36-34, as well as those containing intact chromosome 1, showed suppressed transformed phenotype. Furthermore, several tumourigenic revertant cells were obtained from the hybrid cells. These revertant cells had a morphology similar to that of COKFu cells, and were found to have lost the 1p36 region from the introduced chromosome 1. These results indicate that a normal chromosome 1p36 carries a tumour suppressor gene for colon carcinogenesis.

Suppression of tumorigenicity and invasiveness of colon carcinoma cells by introduction of normal chromosome 8p12-pter.

The development of human colon carcinomas is associated with a number of genetic alterations. A high frequency of deletion of the short arm of chromosome 8 at a late stage of colon carcinogenesis was detected by DNA analysis of colon carcinomas, which suggests the presence of a tumor suppressor gene. We therefore, introduced normal human chromosome 8 into colon carcinoma cells that showed allele loss on 8p21, through microcell hybridization. Five clones of hybrid cells were obtained from independent experiments. Three hybrids exhibited morphological alteration and suppressed tumorigenicity in the subcutis of nude mice, but the other two did not. The difference between the two types of hybrids was the region of the introduced normal chromosome 8: Three hybrids exhibiting morphological alteration and suppressed tumorigenicity had the entire region of the introduced chromosome 8, whereas the other two, exhibiting no change, lacked 8p12-pter from the introduced chromosome. Furthermore, the invasiveness of the hybrids with suppressed tumorigenicity was reduced to one-fifth of that of the parental cells. These results indicate that 8p12-pter carries a gene that contributes to suppression of both tumorigenicity and invasiveness of colon carcinomas.

Increased cell-substratum adhesion, and decreased gelatinase secretion and cell growth, induced by E-cadherin transfection of human colon carcinoma cells.

Metastasis of colon carcinomas is assumed to be caused by multiple steps, which include a loss of cell adhesion that results in the release of carcinoma cells from the original tumor tissue. A human colon carcinoma cell line COKFu was established from a poorly differentiated metastatic adenocarcinoma without cell-cell adhesion and without expression of E-cadherin mRNA and protein. This cell line was co-transfected with mouse E-cadherin cDNA in an expression vector and a neomycin-resistant gene. The parental carcinoma cells had a spindle shape and were scattered, whereas the transfected cells, which expressed exogenous E-cadherin gene, showed a more compact shape with strong cell-cell adhesion and with increased adhesiveness to collagen gel. These cells showed a significantly low anchorage independency (2-7%) and decreased invasiveness (30%) compared to the parental cells. Growth rate of transfectants was decreased both in vitro and in the subcutis of nude mice, with decreased lymphnode metastasis in the case of intravenous injection. It was additionally found that activity of 62 kd gelatinase, secreted from parental cells, was lost or decreased in E-cadherin-transfected cells. These results suggest that E-cadherin is not only involved in the cell-cell adhesion of colon carcinomas, it also has a wider effect, including cell-substratum adhesion and the regulation of proteinase secretion from the cells, resulting in partial suppression of invasiveness and tumorigenic growth.

Malignant transformation of rat embryo fibroblasts by cotransfection with eleven human mutant p53 cDNAs and activated H-ras gene.

Eleven different missense and one nonsense mutant-type p53 cDNAs, which have been frequently detected in human colorectal carcinomas, were constructed and examined for their ability to cooperate with activated human H-ras genes, pSK2 and pHs49, in transfection of rat embryo fibroblasts (REF). Each missense mutant-type p53 cDNA with either of the two activated H-ras genes transformed REF with a different frequency of transformation depending on the different kind of mutation, whereas wild-type p53 (with ras), nonsense mutant-type p53 (with ras), as well as mutant-type p53 (alone) and ras (alone), did not transform REF. Six transformed REF cell lines were established from cotransfection with missense mutant-type p53 cDNA and ras gene; all of them exhibiting exogenous human p53 DNA, RNA, protein, and H-ras DNA and RNA. All six transformed cell lines showed both tumorigenicity and lung metastatic potential in nude mice. They also exhibited 92 kilodalton gelatinase activity, which was not detected in parental REF. These results suggest that missense mutations in p53 gene have a role in malignant transformation as well as metastatic potential.

p300 gene alterations in colorectal and gastric carcinomas.

Colorectal tumors frequently have loss of heterozygosity on chromosome 22q, suggesting that inactivation of tumor suppressor gene(s) on 22q participates in the tumor development. Neurofibromatosis 2 (NF2) gene and E1A binding protein p300 gene, recently identified on 22q, are thought to be candidates for tumor suppressor genes. In this study, mutation of the NF2 gene in 59 colorectal carcinomas, and mutation of the p300 gene in 27 colorectal and two gastric carcinomas, were analysed using PCR-SSCP, RT-PCR-SSCP and direct sequencing methods. Missense mutations of p300 gene were detected in a colorectal carcinoma, and in a gastric carcinoma, though no mutation of NF2 gene was detected. Both p300 mutations were somatic and coupled to deletion of the second allele of the gene, which suggests inactivation of the p300 gene, in these carcinomas. The mutations are located within the Cys/His-rich regions, which are assumed to play important roles in the function of p300. These are the first cases in which p300 gene has been found to be altered in both alleles, suggesting that inactivation of the p300 gene may be involved in the development of carcinomas, and that this gene may be the target of loss of 22q in carcinomas of the digestive tract.

Drastic genetic instability of tumors and normal tissues in Turcot syndrome.

Turcot syndrome is characterized by an association of malignant brain tumors and colon cancer developing in the patient's teens. Since the mechanism of carcinogenesis in Turcot syndrome is still unclear, we analysed genetic changes in tumors from a Turcot patient with no family history of the condition. All tumors, including one astrocytoma, three colon carcinomas, and two colon adenomas, exhibited severe replication error (RER), and all colon tumors showed somatic mutations at repeated regions of TGFbetaRII, E2F-4, hMSH3, and/or hMSH6 genes. Somatic APC mutations were detected in three of three colon carcinomas, and somatic p53 mutations were detected in the astrocytoma and two of three colon carcinomas, both of which showed two mutations without allele loss. We also found that normal colon mucosa, normal skin fibroblasts and normal brain tissue from this patient showed respective high frequencies of RER, in contrast to usual HNPCC patients in which RER was very rare in normal tissues. These results suggest that extreme DNA instability in normal tissues causes the early development of multiple cancer in Turcot syndrome. A missense mutation (GAG to AAG) at codon 705 of hPMS2 gene was detected in one allele of this patient, which was inherited from his mother without tumors. Additional unknown germline mutation may contribute to the genetic instability in normal tissues.

Germ line mutations of hMSH2 and hMLH1 genes in Japanese families with hereditary nonpolyposis colorectal cancer (HNPCC): usefulness of DNA analysis for screening and diagnosis of HNPCC patients.

Mutations in hMSH2 and hMLH1 genes were analyzed in patients from 11 Japanese families that had been diagnosed as carrying hereditary nonpolyposis colorectal cancer (HNPCC) by clinical examination. Germ line mutations of hMSH2 gene were identified in 5 independent families in which colorectal (87% of patients), endometrial (30%), ovarian (17%), gastric (14%), and other cancers existed. Five mutations detected between codons 136 and 811 included single-base substitutions (C-->T and T-->G), a T deletion, and an A insertion, all of which produced stop codons resulting in truncated proteins, and an A-->T substitution at splice donor site of exon 5 which resulted in deletion of this exon. Moreover, one HNPCC family was presumed to have germ line mutation of hMSH2 gene because a somatic mutation of hMSH2 gene was detected in a cancer from a patient in this family. In addition to these 11 families already diagnosed with HNPCC, 3 new families with germ line mutations of hMSH2 gene and hMLH1 gene were found through analysis of DNA from patients who had multiple cancers with alteration in microsatellite DNA. These mutations included an AG deletion at codons 877-878 of hMSH2 gene, an AAG deletion at codons 616-618 of hMLH1 gene, and a C-->T single-base substitution at codon 217 of hMLH1 gene. Seven of eight germ line mutations found in this study are new mutations that have not been reported previously. In families in which germ line mutations were identified presymptomatic examination was then carried out using polymerase chain reaction single-strand conformation polymorphism analysis of DNA from peripheral blood, and the result was the detection of family members predisposed to HNPCC who did not yet show signs of cancer. These results indicate the value of DNA analysis in the screening and diagnosis of HNPCC patients and families.

Preferential hydrolysis of phosphatidylethanolamine in rat ischemic heart homogenates during in vitro incubation.

Phospholipid-hydrolyzing activities were examined in rat hearts with ischemia induced by occlusion of the left main coronary artery. When homogenates of ischemic heart were incubated in vitro at 37 degrees C, a significant amount of phosphatidylethanolamine (PE) was degraded, whereas the contents of other phospholipids did not change significantly. During the incubation, a stoichiometrical amount of lysoPE was concomitantly formed. The lysoPE formed had mainly saturated fatty acids and its composition resembled that of fatty acids detected at the sn-1 position in the glycerol backbone of heart PE. No appreciable PE degradation was observed in homogenates prepared from nonischemic rat heart. No difference in phospholipase activities was found between ischemic and nonischemic heart homogenates when exogenous radioactive phospholipids were used as substrates. Rabbit anti-rat 14-kDa type II phospholipase A2 antibody suppressed the degradation of PE observed in ischemic heart homogenates. These findings indicate that the type II phospholipase A2 activity may be involved in the breakdown of endogenous PE in ischemic heart homogenates.

Hydrolysis of platelet activating factor and its methylated analogs by acetylhydrolases.

We examined the substrate specificity of PAF-degrading enzymes from various sources using platelet activating factor (PAF) and its synthetic analogs. The results were as follows: 1) Tissue-originated acetylhydrolases, such as rat kidney soluble enzyme, deacetylated 1S-methyl-1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (1S-Me-PAF) slightly more rapidly than PAF, whereas plasma acetylhydrolase hydrolyzed PAF more effectively than 1S-Me-PAF. 2) Rat polymorphonuclear leukocytes, monocytes, and lymphocytes homogenates showed an appreciable acetylhydrolase activity, the substrate specificity of which resembled that of the plasma enzyme. 3) Pleural exudates in an experimental pleurisy induced in rats by carrageenan contained an acetylhydrolase activity, the properties of which were similar to those of the plasma enzyme. 4) An extracellular phospholipase A2 activity, which was also observed in the pleural exudate and required Ca2+ ion for maximum activity, seemed not to participate in the deacetylation of PAF, since addition of EDTA did not affect the PAF deacetylation catalyzed by the pleural exudate. These findings indicate that the inactivation reaction of PAF present in the extracellular space is mainly catalyzed by plasma acetylhydrolase, which yields lysoPAF.

Blomhotin: a novel peptide with smooth muscle contractile activity identified in the venom of Agkistrodon halys blomhoffii.

A novel peptide has been isolated from the venom of Agkistrodon halys blomhoffii using a bioassay that monitors the stimulant effect on rat stomach fundus. The 11-amino acid peptide, named blomhotin, was purified to homogeneity by gel-filtration column chromatography and reverse-phase HPLC. The amino acid sequence of blomhotin was determined to be pGlu-Gly-Arg-Pro-Pro-Gly-Pro-Pro-Ile-Pro-Arg, which is similar to that of bradykinin-potentiating peptides which themselves cause no contraction of smooth muscle. The contraction induced by blomhotin showed homologous desensitization, implicating the involvement of a blomhotin-specific site in the response.

Guinea pig bone marrow cells treated with platelet-activating factor generate factor(s) which affects their DNA synthesis and microbicidal activity.

We have previously reported that platelet-activating factor (PAF) induces proliferation and microbicidal activity of guinea pig bone marrow cells. In the present study, we have found that the conditioned medium of PAF- or nonmetabolizable PAF agonist-treated guinea pig bone marrow cells augmented DNA synthesis and induced microbicial activity of bone marrow cells. A PAF specific antagonist, CV-6209, inhibited generation of the active conditioned medium by PAF. Addition of the PAF antagonist only partially suppressed the augmentative effect of the active conditioned medium on DNA synthesis; this is consistent with the fact that, because of the rapid breakdown, no appreciable amount of PAF remained in the conditioned medium of PAF-treated cells. Although mouse bone marrow cells did not respond to PAF unlike guinea pig cells, their DNA synthesis was significantly enhanced by the conditioned medium of PAF-treated guinea pig bone marrow cells. Thus, some newly generated factor(s) distinct from the originally inoculated PAF seemed to modulate the bioactions of PAF on bone marrow cells. An appreciable amount of PAF was produced by calcium ionophore-treated guinea pig bone marrow cells. These findings indicate that PAF synthesized in guinea pig bone marrow cells induces generation in the cells of some factor(s) which affects proliferation or microbicidal activity.