Effects of professional oral health care on elderly: randomized trial

OBJECTIVE

To better understand the role of the professional oral health care for elderly in improving geriatric oral health, the effects of short-term professional oral health care (once per week for 1 month) on oral microbiological parameters were assessed.

METHODS

Parallel, open-labelled, randomize-controlled trial was undertaken in a nursing home for elderly in Shizuoka, Japan. Thirty-four dentate elderly over 74 years were randomly assigned from ID number to the intervention (17/34) and control (17/34) groups. The outcomes were changes in oral microbiological parameters (number of bacteria in unstimulated saliva; whole bacteria, Streptococcus, Fusobacterium and Prevotella: opportunistic pathogens detection: and index of oral hygiene evaluation [Dental Plaque Index, DPI]) within the intervention period. Each parameter was evaluated at before and after intervention period. Four elderly were lost from mortality (1), bone fracture (1), refused to participate (1) and multi-antibiotics usage (1). Finally, 30 elderly were analysed (14/intervention and 16/control).

RESULTS

At baseline, no difference was found between the control and intervention groups. After the intervention period, the percentage of Streptococcus species increased significantly in the intervention group (Intervention, 86% [12/14]; Control, 50% [8/16]: Fisher's, right-tailed, P < 0.05). Moreover, DPI significantly improved in the intervention group (Intervention, 57% [8/14]; Control, 13% [2/16]: Fisher's, two-tailed, P < 0.05). The improvement in DPI extended for 3 months after intervention. None of side effects were reported.

CONCLUSION

The short-term professional oral health care can improve oral conditions in the elderly.

Development of in-vessel components of the microfission chamber for ITER

Microfission chambers (MFCs) will measure the total neutron source strength in ITER. The MFCs will be installed behind blanket modules in the vacuum vessel (VV). Triaxial mineral insulated (MI) cables will carry signals from the MFCs. The joint connecting triaxial MI cables in the VV must be considered because the MFCs and the MI cables will be installed separately at different times. Vacuum tight triaxial connector of the MI cable has been designed and a prototype has been constructed. Performance tests indicate that the connector can be applied to the ITER environment. A small bending-radius test of the MI cable indicates no observed damage at a curvature radius of 100 mm.

Different susceptibility to peroxisome proliferator-induced hepatocarcinogenesis in rats with polymorphic glutathione transferase genes

Although peroxisomal bifunctional enzyme (enoyl-CoA hydratase/L-3-hydroxyacyl-CoA dehydrogenase; BE) is a positive marker for peroxisome proliferation, it is completely absent or expressed very weakly in rat hepatic preneoplastic and neoplastic lesions induced by peroxisome proliferators (PP). After administration of PP for 8-15 weeks, some rats exhibit BE-negative preneoplastic foci but other rats do not. In the present study, to investigate the involvement of glutathione S-transferase (GST) M1 gene polymorphism in interindividual differences in susceptibility to PP, we developed a method to determine the genotypes of rats. We then examined whether rats with one type encoding 198Asn-199Cys (NC-type) or another encoding 198Lys-199Ser (KS-type) exhibit differences in clofibrate (CF) susceptibility. After administration of 0.3% CF for 6 weeks or more, BE-negative foci were found immunohistochemically in KS/KS-type rats, but not in NC/NC-type rats. The number of BE-negative foci in KS/KS rats was 15.3 +/- 9.0 foci/cm2 of liver section after 6 weeks of CF administration, and the values did not alter thereafter. The mean areas of BE-negative foci in KS/KS rat livers increased during the period from 6 to 60 weeks. At weeks 30 and 60, almost all BE-negative foci exhibited a clear cell phenotype, a type of preneoplastic hepatic lesion. BE-negative foci were devoid of peroxisome proliferator-activated receptor alpha, whereas surrounding tissues were positive for the receptor. These results indicate that rats that are polymorphic for the GST M1 gene exhibit different susceptibilities to CF in vivo.

Lipid peroxidation end products-responded induction of a preneoplastic marker enzyme glutathione S-transferase P-form (GST-P) in rat liver on admistration via the portal vein

The in vivo induction mechanism of a preneoplastic marker enzyme, glutathione S-transferase P-form (GST-P), by a number of carcinogens and some noncarcinogens such as anti-oxidants [Proc. Natl. Acad. Sci. U.S.A. 85 (1984) 3964] has remained to be solved. Among the various administration routes tested, GST-P became immunohistochemically demonstrable in the liver centrilobular zone 3 after 24-48h on administration of prostaglandin J2's, 15-deoxy-Delta(12,14)-PGJ2, PGJ2 and Delta(12)-PGJ2 to male rats via the portal vein, whereby the animals had been pretreated with Soya oil intraperitoneally to exhaust fatty acid binding proteins. Unsaturated aldehydes, 4-hydroxynonenal, crotonaldehyde and acrolein, given by the same route induced putatively preneoplastic single cells positive for GST-P. As these lipid peroxidation end products are the substrates as well as inducers of the enzyme, its physiological function could be their detoxication. These results indicate that GST-P expression can be mediated through lipid peroxidation possibly accounting for induction observed with a wide variety of carcinogens. In addition, present method may also be of use as a direct, simple, rapid, and sensitive in vivo test in examination of other biological responses.

KAI1, CAR, and Smad4 expression in the progression of colorectal tumor

PURPOSE

The abnormal expression of several genes is involved in the development of colorectal tumors. The aim of this study was to examine the expression of KAI1, CAR, and Smad4, which has been associated with the progression of other cancers.

METHODS

We examined 12 adenomas, 38 primary carcinomas, 10 liver metastases, and 7 adenocarcinoma cell lines, by fluorescent multiplex reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

KAI1 expression was higher in adenomas (2.55 +/- 0.61; P < 0.05) and primary carcinomas (3.30 +/- 0.42; P < 0.005) than in normal mucosa, but it was not correlated with tumor stage. CAR expression was lower in Dukes' B (1.28 +/- 0.53) than in Dukes' A (2.38 +/- 0.48) (P < 0.05), but increased with tumor progression; Dukes' C (1.45 +/- 0.25), Dukes' D (1.53 +/- 0.14), and metastases (2.09 +/- 0.39) (P < 0.05). Smad4 expression increased in adenomas (2.30 +/- 0.46; P < 0.05), but decreased with tumor progression; Dukes' A (2.14 +/- 0.37), Dukes' B (1.65 +/- 0.41), Dukes' C (1.57 +/- 0.25), Dukes' D (1.08 +/- 0.18), and metastases (0.82 +/- 0.21) (P < 0.05).

CONCLUSIONS

These results suggest that the upregulation of CAR and down-regulation of Smad4 are associated with the progression of colorectal tumors, while the upregulation of these genes and of KAI1 seems to be involved in the early stage.

Alterations in expression of E2F-1 and E2F-responsive genes by RB, p53 and p21(Sdi1/WAF1/Cip1) expression

RB, p53 and p21(Sdi1/WAF1/Cip1) interact in the induction of G1 arrest. We established osteosarcoma cell lines in which a tetracycline-regulatable promoter controls the induction of RB, p53 and p21. By using these cell lines, we investigated whether RB, p53 or p21 regulates, in the same manner or differently, expression and function of E2F-1 and its responsive genes. E2F-1 gene products and transcripts of the E2F-responsive genes decreased in response to RB. Similar changes occurred to p53 and p21 when RB is present. However, in the absence of RB, some of the E2F-responsive genes decreased in response to p53 but not to p21. Thus, RB is a critical component for regulating the E2F-responsive genes, while p53 alone affects only a subset of these genes.

Diagnostic application of CD44 variant expression in pancreatic juice for detection of pancreatic neoplasm

Recently, increased and disorganized expression of CD44 variant exons (CD44v) has been demonstrated in several types of human malignancy. We tried to investigate CD44v expression in pancreatic juice from patients who underwent endoscopic retrograde pancreatography. We analyzed 24 patients with pancreatic neoplasms diagnosed histologically (adenocarcinoma, 17; adenoma, 7) and 15 patients with non-neoplastic lesions. The expression of CD44v mRNA in pancreatic juice was detected by using the reverse-transcription polymerase chain reaction technique followed by Southern hybridization with exon-specific probes. Of 17 patients with adenocarcinoma, 14 (82%) showed expression of CD44v6 mRNA and 11 (65%) showed expression of CD44v2 mRNA. Of 7 patients with adenoma, 6 (86%) were positive CD44v6 mRNA expression and 2 (29%) for CD44v2 mRNA expression; while, out of 15 patients with non-neoplastic lesion, 5 (33%) showed positive findings for CD44V6 mRNA and 3 (20%) for CD44v2 mRNA. Comparing of diagnostic accuracy among CD44v6, CD44v2 and cytological examination, the sensitivities for adenocarcinoma were 82%, 65% and 41% respectively. However, the specificity was lower in CD44v6 (50%), CD44v2 (77%) than in cytology (100%), because CD44v was positive in adenoma cases and normal cases. A combination of RT-PCR analysis for the expression of CD44v with cytological examination in the pancreatic juice may increase the accuracy of diagnosis for pancreatic cancer.

Differences in carcinogenesis by the length of carcinogen exposure period in rat colon

To clarify the carcinogenic factors--whether it is the kind of carcinogen or their length of exposure--that determine whether colorectal cancer develops from an adenoma or develops de novo in the absence of an adenoma, we histopathologically analyzed a total of 229 rat colon tumors induced by administration of 1,2-dimethyl-hydrazine (DMH) or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for three or 15 weeks. In the three-week-exposure groups, 71% of DMH-induced carcinomas and 82% of MNNG-induced carcinomas coexisted with low-grade dysplasia (adenomatous remnant). However, in the 15-week-exposure groups, lowgrade dysplasia was observed in only 10% of DMH-induced and 27% of MNNG-induced carcinomas. Even in the tumors smaller than 20 mm3, it was observed in only 10% of DMH-induced and 32% of MNNG-induced carcinomas. Furthermore, carcinomas without low-grade dysplasia predominated from the initial period of tumor occurrence. Next, we investigated association of K-ras and APC gene mutations with these carcinogenesis patterns in 80 tumors. K-ras mutations were not detected in any tumors induced by three weeks of exposure. However, in the 15-week-exposure groups, this mutation was observed in 57% of DMH-induced tumors and 13% of MNNG-induced tumors. APC mutations in the region homologous to the human mutation cluster region were observed in only 6% of tumors. Thus, our results suggest that the carcinogenesis patterns in rat colon are dependent on the length of exposure to carcinogen and that K-ras mutations were partly involved in a subset of them.

Apoptosis-inducing activity of a driselase digest fraction of green tea residue

We enzymatically digested green tea residue with Driselase, a crude preparation containing cellulase, pectinase and proteases, in order to examine the potential usefulness of the residue. A fraction of the digest soluble in 70% ethanol was found to induce the death of U937 human histiocytic lymphoma cells by apoptosis. Other enzyme preparations gave similar products with cell death-inducing activity of varing potency. The green tea residue may therefore be a useful source of potential agents with anti-cancer activity.

Induction of apoptosis and cell cycle arrest in mouse colon 26 cells by benastatin A

Benastatin A, isolated from Streptomyces bacteria, is reported to inhibit mammalian glutathione transferases (GSTs). Since GST inhibitors such as ethacrynic acid are suggested to induce apoptosis in some cell lines, the effect of benastatin A on the survival of mouse colon 26 adenocarcinoma cells was compared with that of ethacrynic acid. When cells in stationary phase were treated with benastatin A, viable cells were found to be dose-dependently decreased after 3 days. In the case of ethacrynic acid, this became apparent within 24 h. Electrophoretic analysis revealed DNA fragmentation, indicating that cell loss was due to apoptosis in both cases. The dominant GST in colon 26 cells was identified as the class Pi-form (GST-II), and the activities in crude extracts as well as purified GST-II were almost completely inhibited by 50 microM ethacrynic acid. Immunoblot and northern blot analyses revealed increased GST-II protein and mRNA levels in cells treated with ethacrynic acid. Benastatin A did not significantly affect the activity in the crude extract even at 20 microM, a 10-fold higher concentration than that which almost completely inhibited the activity of purified GST-II. However, GST activity and GST-II protein were decreased in colon 26 cells treated with benastatin A for 5 days, no significant activity being detected in the range of 16 - 20 microM. In addition, beta-actin and bax mRNAs were also decreased in a dose-dependent manner. Furthermore, flow cytometric analysis of colon 26 cells revealed that benastatin A blocked the cell cycle at the G1/G0 phase. Thus, benastatin A also induces apoptosis of colon 26 cells, but this is unlikely to be due to inhibition of GST activity.

Blood flow and leukocyte adhesiveness are reduced in the microcirculation of a peritoneal disseminated colon carcinoma

Dynamic behavior of leukocytes in the microcirculation of solid tumor tissue was visualized using a fluorescent labeling technique combined with the use of a real-time confocal laser-scanning microscope (CLSM) system. Colon tumor cells (RCN-9) were inoculated into the peritoneal cavity of male Fischer 344 rats. Tumor-free rats were similarly injected with physiological saline (intraperitoneally). Ten days after tumor inoculation, the mesentery was exteriorized and subjected to vital microscopic observation under the CLSM system. Leukocytes were labeled with rhodamine 6G (100 microg kg(-1), intravenously), and their behavior within the microvessels (10-30 microm in diameter) was analyzed both in the solid tumor tissues and the normal mesentery. Wall shear rate was calculated from the measured values of vessel diameter and erythrocyte flow velocity. In tumor microvasculature of tumor-bearing rats, the centerline erythrocyte velocity (0.73 +/- 0.58 mm s(-1), mean +/- standard deviation) and wall shear rate (210 +/- 151 s(-1)) were significantly lower than those of the tumor-free rats (1.27 +/- 0.83 mm s(-1), 344 +/- 236 s(-1), respectively). Despite such reduced flow conditions, flux of the rolling leukocytes as well as density of the adhered leukocytes both decreased significantly in tumor microvasculature as compared with normal controls. The methods developed in this work show promise in improving our understanding of tumor biology and pathophysiology.

Identification of glutathione S-transferase p-1 as the class pi form dominantly expressed in mouse hepatic adenomas

To clarify which of the two genes for pi class glutathione S-transferases (GSTs) (p-1 and p-2) is dominantly expressed in mouse hepatic adenomas, the relative mRNA levels were examined by means of the reverse transcription-polymerase chain reaction (RT-PCR). Hepatic adenomas were induced in male and female B6C3F1 mice by diethylnitrosamine treatment. Northern blot analysis revealed that pi class mRNA levels were decreased in adenomas of male mice, but increased in those of females, with reference to the respective surrounding non-adenoma tissues. In contrast to the marked sex difference in surrounding tissues, pi class GST mRNA levels in adenomas were almost the same in both males and females. To evaluate p-1 and p-2 mRNA levels separately, the products of RT-PCR employing primers common for both cDNAs were digested with the endonuclease BanI (specific for p-2) and then resolved by electrophoresis. The p-1 mRNA was thus found to be dominant in adenomas of both female and male mice. The p-2 mRNA levels were increased in the lesions as compared with those in the surrounding non-adenoma tissues. Recombinant p-1 and p-2 proteins were expressed in Escherichia coli. Unlike p-1, the p-2 protein did not show any significant activity towards 1-chloro-2,4-dinitrobenzene and did not bind to S-hexylglutathione-Sepharose despite immunological cross-reactivity. The dominant pi class form in adenomas could also be identified as p-1 by its binding to S-hexylglutathione-Sepharose. Single radial immunodiffusion analyses confirmed that the p-1 protein levels were in line with the mRNA findings, i.e., 1.9+/-0.3 mg/g adenoma as compared to 6.5+/-1.2 mg/g non-adenoma tissue for males and 2.2+/-0.6 mg/g as compared to 0.7+/-0.2 mg/g for females. The results thus indicated that the change of pi class forms in adenomas is caused mainly by alteration in the p-1 level and the contribution of p-2 is minimal.

Hepatocyte culture utilizing porous polyvinyl formal resin maintains long-term stable albumin secretion activity

To investigate the effects of culture conditions on the maintenance of metabolic functions of cultured hepatocytes, long-term hepatocyte culture lasting 20 days was performed under two different culture conditions, i.e. stationary cultures utilizing porous polymer (polyvinyl formal (PVF) resin) as a substratum and conventional monolayer dish cultures without PVF. Metabolic activities specific to hepatocytes were evaluated in terms of ammonia metabolism, urea synthesis, and albumin secretion. Concerning ammonia metabolic and urea synthetic activities, no significant differences in maintenance of these activities were found between the two culture conditions, and these activities rapidly decreased with the elapse of the culture period, especially during the early stage of the experiments. However, after day 10, these activities in the stationary cultures were maintained at a slightly more favorable level than in the monolayer cultures. On the other hand, compared with ammonia metabolism and urea synthesis, stable and well-maintained albumin secretion of hepatocytes (60% of the activity in day 1) was exhibited in the stationary culture experiments, despite that this particular activity under the monolayer culture condition gradually reduced to a very low level (5.7% of that on day 1) at the end of the culture. From the morphological observations, hepatocytes immobilized in the PVF resin revealed individual spherical shapes without forming multicellular aggregation, and it was suggested that this characteristic structure contributed to good albumin secretion of hepatocytes. In conclusion, the advantages of the hepatocyte culture technique utilizing PVF resin over the conventional dish culture in maintaining some representative metabolic function specific to hepatocytes were clarified.

Phenotypic alterations of small cell lung carcinoma induced by different levels of wild-type p53 expression

p53 induces both growth arrest and apoptosis in cancer cells. To clarify whether the level of p53 expression determines the response of small cell lung carcinoma (SCLC) cells, we assessed the effect of various p53 levels on a p53-null SCLC cell line, N417, using a tetracycline (Tc)-regulated inducible p53 expression system. Apoptosis was induced in SCLC cells with high p53 expression. Although low levels of p53 induced G1 arrest accompanied by p21 expression, cells with G1 arrest seemed to undergo apoptosis after further cultivation. Expression of exogenous p21 induced G1 arrest but not apoptosis in SCLC cells, suggesting that p53-mediated G1 arrest was induced through p21 expression. Moreover, high level of p53 expression down-regulated Bcl-2 expression in SCLC cells, while Bax was consistently expressed irrespective to the level of p53 expression. These results suggest that p53-mediated apoptosis and G1 arrest depend on level of p53 expression in SCLC cells and that the relative dominancy of Bax to Bcl-2 is involved in the induction of apoptosis by high level of p53 expression.

Kinetic evaluation of beta-neoendorphin hydrolysis by the somatic and testicular isozymes of human angiotensin-converting enzyme

Angiotensin-converting enzyme (ACE) has both somatic and testicular isozymes, the former possessing two catalytically active domains, amino-terminal and carboxyl-terminal, while the latter has only the carboxyl-terminal one. We compared hydrolysis processes of the nonapeptide beta-neoendorphin by the two isozymes of human ACE. Both isozymes hydrolyzed the peptide to Tyr1-Gly2-Gly3 by the sequential removal of carboxyl-terminal dipeptides in three consecutive steps. The rate constant values for the second step, conversion of beta-neoendorphin1-7 to Leu-enkephalin, by the somatic isozyme in the presence of 10 or 200 mM NaCl were 4-fold higher than those for the first step, conversion of beta-neoendorphin1-9 to beta-neoendorphin1-7. The k(cat) values of the somatic isozyme for beta-neoendorphin1-7 were 2-fold higher than those for beta-neoendorphin1-9, indicating that beta-neoendorphin1-7 is more rapidly hydrolyzed than beta-neoendorphin1-9. The rate constant value for the second step at 10 mM NaCl was 5-fold higher than that for the testicular isozyme. Similar extent of difference was also observed in k(cat) values for beta-neoendorphin1-7 between the two isozymes. These results suggest that the amino-terminal domain of the somatic isozyme mainly contributes to the conversion of beta-neoendorphin1-7 to Leu-enkephalin at a low NaCl concentration. Optimal chloride concentrations for the individual steps of beta-neoendorphin1-9 hydrolysis differed between the two isozymes.

Differentiation induced by RB expression and apoptosis induced by p53 expression in an osteosarcoma cell line

Multiple genetic alterations, including concurrent inactivation of RB and p53, occur frequently in several human cancers. To investigate the biological significance of RB and p53 gene inactivations, a wild-type RB or p53 cDNA expression vector regulated by tetracycline was introduced by stable transfection into an osteosarcoma cell line Saos-2, in which both the RB and p53 genes were inactivated. Induction of introduced RB expression resulted in suppression of cell growth, increased percentage of cells at the G0/G1 phase, and enlargement of the cells. Furthermore, activity of alkaline phosphatase was increased and expression of fibronectin was decreased, suggesting the induction of cell differentiation by RB expression. Induction of p53 expression also resulted in significant suppression of cell growth with slight accumulation of cells at the G0/G1 and G2/M phases. The cells were detached from culture dishes and the dead cell fraction increased. Furthermore, condensation of chromatin and DNA fragmentation were observed, suggesting the induction of apoptosis by p53. These results suggest that RB and p53 play different roles in carcinogenesis of osteoblast; RB inactivation releases cells from G0/G1 arrest and suppresses cell differentiation while p53 inactivation assists the cells to proliferate by repressing both apoptosis and cell cycle arrest at G0/G1 and G2/M.

Evaluation of DNA polymerase beta gene mutation as a genetic marker for colorectal carcinoma

DNA polymerase beta is known to be involved in repair of DNA damage. Frequent mutation of its gene in the segment encoding amino acids 149-297 has been reported in colorectal cancer. To investigate whether mutation in this region is available as a genetic marker for colorectal cancer, 11 primary tumors and 4 liver metastases from 11 patients were examined by fragment length analysis and single-strand conformation polymorphism (SSCP) analysis of reverse-transcription polymerase chain reaction (RT-PCR) products. Although allelic imbalance in the p53 and DCC genes were observed in ten out of eleven primary tumors and all liver metastases using a dinucleotide repeat polymorphism, mutation was not detected in the DNA polymerase beta mRNA. Neither was it detected in seven colon cancer cell lines. Present results suggest that mutation in this region is uncommon in colorectal cancers and is not a useful genetic marker for colorectal cancer.

Induction of apoptosis but not G1 arrest by expression of the wild-type p53 gene in small cell lung carcinoma

Multiple genetic alterations, including inactivation of the p53 and RB genes and loss of heterozygosity on chromosome 3p, occur commonly in small cell lung carcinoma (SCLC). To assess the biological significance of p53 inactivation in the development of SCLC, tetracycline (Tc)-inducible p53 expression plasmids were introduced into a SCLC cell line, N417, in which the p53 gene as well as the RB gene was inactivated. In the absence (induced) of Tc, cells transfected with the wild-type p53 gene formed colonies in 29-58% of those with a mutant p53 gene. However, wild-type p53 genes were expressed in 0 of 43 transfectants, whereas mutant p53 genes were expressed in 75% (36/48) of the transfectants, suggesting that the growth of SCLC cells was suppressed by the expression of the wild-type p53 gene. Thus, wild-type p53-inducible clones were further established by transfection in the presence (repressed) of Tc. The in vitro growth was significantly suppressed by the induction of wild-type p53 expression, and apoptosis but not G1 arrest was observed within 24 h of p53 induction. These results strongly suggest that the restoration of the p53 function is sufficient to suppress the growth of SCLC cells in which other genetic alterations remain uncorrected, and that growth suppression by p53 is due to induction of apoptosis but not due to induction of G1 arrest through the RB pathway.

Alternative splicing of the neurofibromatosis 1 gene correlates with growth patterns and neuroendocrine properties of human small-cell lung-carcinoma cells

Two distinct transcripts, type I and type II, of the neurofibromatosis I (NFI) gene are generated by alternative splicing in the region corresponding to the gene's GTPase-activating protein-related domain (GRD). Relative expression levels of these 2 transcripts were previously correlated to neural differentiation. Since small-cell lung carcinoma (SCLC) often exhibits neuroendocrine properties, we analyzed the type-I to type-II mRNA ratio in 15 SCLC cell lines, using reverse transcriptase and polymerase chain reaction methods. The type-I mRNA was predominant in 10 cell lines; 8 of them grew as floating aggregates in culture and had high L-dopa decarboxylase (DDC) activity. The other 5 lines predominantly expressed type-II mRNA, adhered to the culture substrate, and expressed low or undetectable levels of neural cell-adhesion molecule (NCAM) antigen and DDC activity. N2+, one of the subclones of NCI-N417 cells, exhibited a higher type-I to type-II ratio after the cells had adhered to a laminin-coated plate and had emitted neurite-like processes. These findings provide evidence that alternative splicing patterns of NFI mRNA correlate with the mechanisms that regulate the growth patterns and neuroendocrine properties of SCLC cells in vitro.

Reconstitution of the RB gene suppresses the growth of small-cell lung carcinoma cells carrying multiple genetic alterations

Multiple genetic alterations, including inactivation of the RB gene, occur commonly in small-cell lung carcinoma (SCLC). To assess a functional role of RB inactivation in the development of SCLC, an RB expression plasmid was introduced by stable transfection into SCLC cell lines, Lu-135 and N417, in which the RB gene was inactivated. Lu-135 and N417 cells transfected with the wild-type RB gene formed G418-resistant colonies twofold less efficiently than those with a mutated RB gene or with the control vector. Intact exogenous wild-type RB genes were detected only in approximately 20% of G418-resistant clones; three of 14 in Lu-135 and three of 16 in N417, respectively. Transcripts from the transfected RB gene were also detected in two of these three clones from Lu-135 and two of three from N417 but the amount of RB mRNA and protein was less than one fifth of that in normal fibroblast cells WI-38. Furthermore, clones with exogenous wild-type RB expression showed either reduced growth rates in culture or suppressed tumorigenicity in nude mice. These findings suggest that functional correction of the RB gene is sufficient to suppress the growth of SCLC cells, even though several other genetic alterations in the cells remain uncorrected.

Morphological changes of endothelial cells after exposure to fluid-imposed shear stress: differential responses induced by extracellular matrices

Effects of extracellular matrices (ECMs) and fluid-imposed shear stress on the cell shape and the cytoskeletal structure of microfilaments were studied in cultured porcine aortic endothelial cells (PAECs). The PAECs were cultured until confluent on non-coated or on ECM-coated glass coverslips. The components of ECM used were type IV collagen, heparan sulfate, chondroitin sulfate and dermatan sulfate. The PAECs cultured on the mixed ECMs showed marked elongation and segmental orientation with randomly distributed cell axis even under a no-flow static condition, and the microfilaments were mostly observed in parallel with the cell axis. After shear flow exposure (2 Pa, 24-48 hrs), the PAECs on non-coated glass were significantly elongated and oriented to the flow direction, however the PAECs on ECM-coated glass showed more retarded responses than the ones on non-coated glass, indicating that the anchorage to the substrate was enhanced by ECMs. The stress fibers were reorganized in accordance with the cell shape and oriented to the flow direction. These findings suggest that ECM may act together with shear stress to modify and maintain the endothelial cell configuration.

[Accumulation of genetic alterations during human tumor progression]

This study was designed to identify tumor suppressor genes whose inactivation is associated with the acquisition of metastatic ability in colorectal carcinoma. The results indicate that a specific subset of tumor suppressor genes is involved in metastasis of colorectal carcinoma. First, both the p53 and DCC genes were altered in 100% of liver metastases. Second, the incidence of loss of heterozygosity (LOH) at loci on chromosomes 13q, 14q, and 18q in liver metastases was higher than in primary tumors. Third, LOH or rearrangement not detected in the primary tumors was observed on chromosomes 13q, 14q and 18q in liver metastases from the same patients, while alterations on chromosome 17p were always detected in both lesions. These observations indicate that concordant inactivation of the p53 and DCC genes and inactivation of several tumor-suppressor genes, especially those on chromosomes 13q and 14q, play important roles in the acquisition of metastatic potential in colorectal carcinoma.

Concordant p53 and DCC alterations and allelic losses on chromosomes 13q and 14q associated with liver metastases of colorectal carcinoma

To identify genetic alterations associated with acquisition of metastatic ability in colorectal carcinoma, 31 liver metastases and 40 primary tumors of colorectal carcinoma from 55 patients were analyzed for loss of chromosomal heterozygosity using 46 polymorphic DNA markers covering 15 chromosomes. Loss of heterozygosity (LOH) and/or rearrangement at the TP53 and DCC loci were detected in all liver metastases (10 of 10 at TP53 and 19 of 19 at DCC), and were observed in 59% (10 of 17) at TP53 and 75% (18 of 24) at DCC respectively in the primary tumors. Furthermore, the incidence of LOH on chromosomes 13q and 14q was higher than that on other chromosomes in liver metastasis, and it was higher in liver metastases than in primary tumors (20/30 vs. 18/39, p = 0.072 on chromosome 13q and 21/31 vs. 16/40, p = 0.018 on chromosome 14q). In 4 cases, LOH or rearrangement at loci on chromosomes 13q, 14q and 18q not detected in primary tumors was observed in liver metastases from the same patients. These results suggest that concordant p53 and DCC alterations and inactivation of several other tumor-suppressor genes, especially those on chromosomes 13q and 14q, play important roles in the acquisition of metastatic potential of colorectal carcinoma.

Time course changes in cytoskeletal structures of cultured endothelial cells exposed to shear stress

Changes in patterns of microfilament distribution were analyzed using cultured porcine aortic endothelial cells under shear flow. Within the elongated endothelial cells after shear flow exposure (20 dyne/cm2, 0-24 h), F-actin filaments were mainly observed as stress fibers. After 24 h exposure, the fluorescence intensity of rhodamine-phalloidin-stained cells was enhanced, indicating the increase in F-actin content. It was suggested that not only F-actin distribution but also the content may be affected by shear stress at the early stage of exposure.

Central nervous system involvement of adult T-cell leukemia-lymphoma with multinucleated giant cells in the brain, skin, and kidney

BACKGROUND

A case of central nervous system (CNS) involvement in a patient with adult T-cell leukemia-lymphoma (ATLL) with multinucleated giant cells (MNGC) is presented.

METHODS

A 48-year-old woman with human T-lymphotropic virus type I (HTLV-I) antibody titer had multiple focal brain symptoms and skin eruptions without lymphadenopathy, hepatosplenomegaly, or increased abnormal lymphocytes in the peripheral blood. No spastic paraparesis of the lower limbs was found. The encephalopathy was progressive, and she died 5 months later despite repeated intrathecal administration of methotrexate, cytosine arabinoside, and prednisolone and monthly systemic chemotherapy with doxorubicin, cyclophosphamide, vincristine, and prednisolone.

RESULTS

Postmortem examinations identified unusual ATLL lesions composed of marked infiltrations of atypical mononuclear cells and bizarre MNGC with histiocytic granulomatous reactions in the leptomeninges, brain tissues along the Virchow-Robin spaces, skin, and kidney. Immunohistochemical stains confirmed the T-cell nature of such mononuclear cells and partially T-cell and partially macrophage nature of the MNGC, although no evidence of HTLV-I expression was found.

CONCLUSIONS

ATLL presenting with CNS symptoms is rare. It was assumed that the direct cytopathic effects of HTLV-I were responsible for the formation of the MNGC after considering the similarity with MNGC in encephalopathy caused by the human immunodeficiency virus.

Changes in the microstructure of cultured porcine aortic endothelial cells in the early stage after applying a fluid-imposed shear stress

Time course changes in the cell shape and in the patterns of microfilament distribution were analyzed quantitatively using cultured porcine aortic endothelial cell monolayers before and after a shear flow exposure. Geometrical parameters of the cell and of the microfilament were measured on fluorescent photomicrographs of the cells stained with rhodamine-phalloidin. After the shear flow exposure (20 dyn cm-2, 0-24 h), the endothelial cells on glass were elongated and oriented to the direction of the flow. Under the no-flow condition, F-actin filaments were mainly localized at the periphery of the cell, although some filaments were seen in the more central portion. The angles of the filaments were randomly distributed. After 3 h, the stress fiber-like structure of an F-actin bundle was formed in the central part of the cells, and these filaments were oriented to the direction of the flow. The degree of orientation increased as the time of exposure to shear stress became longer. This change in F-actin preceded cell elongation and orientation; these changes were statistically significant only after 6 h. After 24 h, peripheral filaments were again observed, and the fluorescence intensity of rhodamine-phalloidin-stained cells was enhanced. These findings suggest that the redistribution of F-actin filaments is one of the early cellular responses to the onset of shear stress and that it is one of the most important factors controlling cell elongation and orientation to the direction of the flow.

Platelet thrombi produced on cultured endothelial cells by the dye/light method

Platelet adhesion and aggregation were induced on cultured endothelial cells using the fluorescent dye/light method. A cone-and-plate apparatus was newly developed to observe interactions between platelets and cultured endothelial cells under a shear flow condition. The platelet deposition grew on the light-irradiated area of the cells. Degree of endothelial cell injury induced by the dye/light reaction seemed to depend on the dye concentration. Application of either aspirin or indomethacin significantly inhibited the growth of platelet aggregation, but was not effective for the platelet adhesion to endothelial cells. The platelet thrombi were formed on endothelial cells without their denudation. It was found by transmission electron microscopy that platelets directly adhered to endothelial cells which were not seriously damaged. This thrombus model is expected to be applicable to some physiological and pharmacological studies investigating platelet-endothelial cell interaction and mechanism of platelet thrombus formation in blood vessels.

Emigration of activated leukocytes augments transvascular permeability in mesenteric venules of rat

Effects of leukocyte adhesion and emigration on the microvascular permeability were analyzed by the combined use of high resolution transilluminated intravital microscopy and the epiilluminated fluorescent tracer imaging. After stimulating leukocytes by topical application of PAF-LPS or fMLP solution on the mesentery of a rat, a dynamic process of leukocyte emigration was visualized under high resolution transilluminated microscopic observation. When considerable emigration of leukocytes was observed, the same microvasculature was subjected to a permeability study to visualize the diffusional process of the FITC-labeled macromolecules under an epiilluminated fluorescent microscope. Dye diffusion was accelerated in the PAF-LPS or fMLP-treated group, and also a distinctly spotty leakage was observed in venules where successive adhesion and emigration of leukocytes were observed.

Performance of a new hybrid artificial liver support system using hepatocytes entrapped within a hydrogel

To develop a hybrid artificial liver support system (ALSS), the authors constructed a rotating-disk type ALSS using hepatocytes entrapped within a calcium alginate hydrogel. This module was designed in imitation of the gas-liquid contactor that uses the same principle. Forty disks with film-shaped hydrogel were mounted to a horizontal rotating axis and were kept in contact with blood. The concentration of hepatocytes in the gel varied from 1.9 X 10(9) to 1.7 X 10(10) cells/L gel. Entrapping hepatocytes within hydrogel kept the hepatocytes viable, and results of in vitro experiments showed ammonium metabolism and urea synthesis. The results of ex vivo perfusion experiments using cats with acute hepatic insufficiency indicated that this module had the ability to replace liver function in vivo.