Carotid atherosclerosis and a reduced likelihood for lowered cognitive performance in a Canadian First Nations population

BACKGROUND

We investigated the associations among cardiovascular risk factors, carotid atherosclerosis and cognitive function in a Canadian First Nations population.

METHODS

Individuals aged > or = 18 years, without stroke, nonpregnant and with First Nations status were assessed by the Trail Making Test Parts A and B. Results were combined into a Trail Making Test executive function score (TMT-exec). Doppler ultrasonography assessed carotid stenosis and plaque volume. Anthropometric, vascular and metabolic risk factors were assessed by interview, clinical examinations and blood tests.

RESULTS

For 190 individuals with TMT-exec scores, the median age of the population was 39 years. Compared to the reference group, individuals with elevated levels of left carotid stenosis (LCS) and total carotid stenosis (TCS) were less likely to demonstrate lowered cognitive performance [LCS, odds ratio (OR): 0.47, 95% confidence interval (CI): 0.24-0.96; TCS, OR: 0.40, 95% CI: 0.20-0.80]. No effect was shown for plaque volume. In structural equation modeling, we found that for every 1-unit change in the anthropometric factor in kg/m(2), there was a 0.86-fold decrease in the percent of TCS (p < 0.05).

CONCLUSIONS

Individuals with elevated levels of LCS and TCS were less likely to demonstrate lowered performance. There was some suggestion that TCS mediates the effect of anthropometric risk factors on cognitive function.

Therapeutic vaccination against advanced pancreatic cancer by autologous dendritic cells pulsed with a MUC1 peptide: Preclinical results of a clinical phase I trial

e15652

Background: Pancreatic ductal adenocarcinoma has a particularly poor prognosis. Therefore, novel therapeutic strategies such as immunotherapy are required. The aim of the present phase I study was to evaluate the safety, immune responses and clinical activity of a vaccine based on autologous dendritic cells (DC) pulsed with a specific MUC1 peptide in advanced pancreatic cancer patients. Methods: Five patients who had pancreatic cancer ductal adenocarcinoma expressing MUC1 in stage of III/IV were enrolled to the clinical trial. Patients underwent leukapheresis to generate dendritic cells by culture in vitro with granulocyte macrophage colony-stimulating factor and interleukin-4 for 5 days. Dendritic cells were then pulsed overnight with MUC1 peptide (GVTSAPDTRPAPGSTAPPAH) and harvested for vaccination. Dendritic cells (3×106-6×106) were injected intradermally every 2 weeks for 3–4 times. Results: All patients remained with progressive disease. Four patients developed strong T-cell IFN-γ and Granzyme B Elispot responses to the vaccine. Most interestingly, the patient who was treated with the highest number of DC(6×106) had more number of CTL than other patients and showed delayed-type hypersensitivity responses at injection sites and this patient stopped application of the analgetics. Another patient with relapsed pancreatic cancer who had finished the 4 times of vaccination and then followed 6 times of chemotherapy with Gemcitabine had a surprisingly long term of survival of 12 month. No evidence of significant treatment related toxicity or auto-immunity was observed. Conclusions: This study showed the safety and clinical response of MUC1 peptide-pulsed dendritic cell therapy for patients with advanced pancreatic cancer. It confirms the capability of this DC vaccine to stimulate an immune response in patients with pancreatic cancer even in the presence of a large tumor burden. Dendritic cell therapy is recommended for further clinical studies in pancreatic cancer patients.

No significant financial relationships to disclose.

A novel recombinant tandem repeat DNA vaccine targeting at MUC1

3066

Background: Tandem repeat (TR) is the key epitope of mucin 1 (MUC1) for inducing cytotoxic T lymphocytes (CTL) to kill the tumor cells specifically. A novel recombinant TR DNA vaccine was constructed to study its induced immune responses. Methods: A recombinant human TR (rhTR) gene encoding a single TR polypeptide of MUC1 was synthesized and cloned into the multiple cloning sites of plasmid pcDNA3.1/Myc-his (+) A to construct the recombinant plasmid pcDNA3.1-TR/Myc-his (+) A (pTR plasmid). Expression of pTR plasmid was confirmed by transfection assay and Western blot analysis. C57BL/6 (H-2b) mice were immunized with pTR plasmid (n=15) by tibial muscle injection. Mice inoculated with the empty vector (EV group, n=15) and 0.9% NaCl solution (NS group, n=15) were used as vector and blank control respectively. Four weeks later, all mice were immunized again. Specific antibody detection and cytotoxic assay were used to evaluate the vaccine-induced TR specific immune responses. Results: DNA sequencing confirmed that the pTR plasmid was exactly constructed. Transfection assay and Western blot analysis found that the transfected COS7 cells expressed TR polypeptide of MUC1 48 hours after transfection. Cytotoxic assay showed that immunization with pTR plasmid into C57BL/6 mice resulted in more efficient induction of CTL specific cytolysis against TR polypeptide than that of EV group and NS group (p<0.01). Vaccine immunized mice had a higher equivalent concentration of anti-TR specific antibodies (2324μg/ml±238μg/ml) than that of EV group (1896μg/ml±533μg/ml, p<0.01) and NS group (1736μg/ml±142μg/ml, p<0.01). Conclusions: The novel recombinant TR DNA vaccine targeting at MUC1 was exactly constructed, immunization with which could induce TR specific CTL response and antibodies response in mice.

No significant financial relationships to disclose.

[Studies on the feasibility of detecting circulating antibodies in saliva of Schistosoma japonicum infected rabbits]

AIM

To investigate the feasibility of detecting anti-Schistosoma japonicum antibodies in saliva.

METHODS

Saliva and serum samples of 5 infected, 7 reinfected and 8 treated rabbits were collected at different times periods. The CAb in saliva and serum was detected by using ELISA.

RESULTS

The sensitivity of ELISA was 94.7% for saliva and 100% for serum. The specificity of ELISA was 100% for both saliva and serum.

CONCLUSION

Saliva can be used to detect circulating antibodies for the diagnosis of schistosomiasis japonica.

[Preparation of monoclonal antibodies by intrasplenic immunization of mice with urine circulating antigen from patients infected with Schistosoma japonicum]

AIM

To explore an efficient method for preparing monoclonal antibodies against circulating antigen of S. japonicum in the urine of schistosomiasis patients.

METHODS

The urine of schistosomasis patients were precipitated with 5% trichloroacetic acid, and then used to immunize the BALB/c mice by intrasplenic immunization to prepare McAb.

RESULTS

Two monoclonal cell lines against the CAg in the urine of schistosomiasis patients have been established. The immunoglobulin subclass of the 2 McAbs (2E6 and 2B11) were identified as IgM. The titres of 2E6 and 2B11 were 2.56 x 10(5) and 6.4 x 10(4). On immunodiffusion, McAb 2E6 showed one precipitation line with IHU-CAg, however, both McAbs did not react with NHU-CAg. Using ascitic fluid of 2B11 and 2E6 as capture antibody separately, and HRP-H11 as labelled antibody to detect the urine of 12 acute schistosomasis patients, 2B11 2E6 gave 6 and 3 positive, respectively, whereas 8 normal urine were all negative.

CONCLUSION

It is feasible to use CAg from schistosomasis patients' urine to prepare anti-CAg McAb by intrasplenic immunization in mice.

[Determination of circulating antigen in urine of rabbits infected with Schistosoma japonicum]

AIM

To develop an immunoassay for the detection of circulating schistosome antigen (CSA) in host urine.

METHODS

CSA extracted from the urine of the rabbits infected with Schistosoma japonicum was used for preparing and selecting specific monoclonal antibody. A one-step dot-ELISA using this specific McAb and a 2nd antibody was used for detection of circulating schistosome antigen in the urine of infected rabbits.

RESULTS

No CSA was detected in urine from all of 22 rabbits before infection. The positive rate of CSA in infected rabbits was correlated with the intensity of infection and the time of infection. No CSA was detected in the urine rabbits of 3 weeks after infection with 25 cercariae while the positive rate of CSA in the urine from rabbits infected with 200 cercariae was 40% and 100% after 3 and 6 weeks, respectively. A combination of CSA detection in both urine and serum may increase the detectability.

CONCLUSION

The specific McAb prepared by urine CSA of Schistosoma japonicum-infected rabbits can be used as a probe for detecting CSA in the urine of infected rabbits.

[Establishment and application of dipstick sandwich colloidal dye immunoassay for circulating antigen detection in schistosomiasis patients]

AIM

To set up a simple immunoassay for the detection of circulating antigens in host serum.

METHODS

A kind of colloidal pale purple dye (HFRL) used as a staining reagent for immunoassay was first selected from the dyes produced in China and an optimum condition for labelling the dye onto the combined IgM antibodies was explored. A dipstick sandwich colloidal dye immunoassay (DS-DIA) for the detection of circulating antigens in host sera was established.

RESULTS

The minimal concentration of SEA detected was 5 ng/ml by DS-DIA. Serum circulating antigen detection in 14 cases of acute schistosomiasis japonica, 113 chronic cases and in 113 healthy controls revealed that the sensitivity was 100% in acute cases, 52.2% in chronic cases and the specificity was 92.9% for uninfected students. The sensitivity and specificity of DIA were similar to those of dot-ELISA. A certain degree of diagnostic complementarity up to 76.1% in sera from these patients was seen when DS-DIA and dot-ELISA were used in paralle.

CONCLUSION

DS-DIA is a simple, economical and reliable method for detecting circulating antigens of Schistosoma japonicum, having a wide potential value especially for field use.

[Comparative observation on the efficacy of several test/probe systems for detecting schistosome circulating antigen]

AIM

To compare the efficacy of 5 test/probe systems for the detecting of schistosomal circulation antigen (SCA) in sera from infected rabbits.

METHODS

Nine rabbits were infected with monosexual cercariae (either male or female), 7 rabbits were infected with bisexual cercariae as controls. Blood samples were collected periodically post infection (p.i). 15 rabbits were infected each with 250 bisexual cercaria and divided into 3 groups, 2 groups were treated with allyl thiourea (295-590 mg/kg) from 19 d or 46 d respectively, to inhibit their egg formation. One untreated group was used as control. Blood samples were collected weekly until 8 wk post infection. SCA detecting methods include (1) dot-ELISA/McAb anti-surface membrane antigen of adult worms (8SE4), (2) dot-ELISA/McAb anti-CCA (3D10), (3) Sandwich dot-ELISA/McAb anti-egg antigen (MG2), (4) Sandwich-ELISA/McAb anti-egg antigen (2H10), (5) Sandwich-ELISA/McAb anti-CAA (1B10).

RESULTS

Using method (1) all of the 18 rabbits infected with monosexual cercariae were negative. Using method (2) only 1 rabbit harboured 133 male worms showed positive. Using method (5) no SCA were detected in sera from female cercariae-infected rabbits but 3 out of 9 male cercariae-infected rabbits showed positive reaction. SCA detecting results from rabbits treated with allyl thiourea: both method (1) and (3) showed negative in rabbits treated from 19 d (p.i.) but all gave positive reaction in 6-7 wk in rabbits treated from 46 d (p.i.). There were all negative detected by using method (4) and all positive at 6 wk (p.i.) detected by method (5) in rabbits of 3 groups whether treated or non-treated.

CONCLUSION

Various test/probe systems have different efficacy in detecting SCA but (5) of the methods (1)(2) tests/probe systems could not detect SCA in rabbits with single female cercariae infection. From the egg formation inhibition study, the SCA detected by McAb 8SE4 dot-ELISA might be related to egg maturation. Whether the surface membrane antigen of adult worm has common antigenic component with egg antigen remains to be studied.

Artificial neural network-based predictive model for bacterial growth in a simulated medium of modified-atmosphere-packed cooked meat products

The data of Devilieghere et al. (Int. J. Food Microbiol. 1999, 46, 57--70) on bacterial growth in a simulated medium of modified-atmosphere-packed cooked meat products was processed for estimating maximum specific growth rate mu(max) and lag phase lambda of Lactobacillus sake using artificial neural networks-based model (ANNM) computation. The comparison between ANNM and response surface methodology (RSM) model showed that the accuracy of ANNM prediction was higher than that of RSM. Two-dimensional and three-dimensional plots of the response surfaces revealed that the relationships of water activity a(w), temperature T, and dissolved CO(2) concentration with mu(max) and lambda were complicated, not just linear or second-order relations. Furthermore, it was possible to compute the sensitivity of the model outputs against each input parameter by using ANNM. The results showed that mu(max) was most sensitive to a(w), T, and dissolved CO(2) in this order; whereas lambda was sensitive to T the most, followed by a(w), and dissolved CO(2) concentrations.

[Study on the relation between the cell cycle regulators and laryngeal carcinogenesis]

OBJECTIVE

To investigate the clinicopathological significance of the Cyclin E, p21WAF1/CIP1 and p53 expression in laryngeal carcinogenesis.

METHOD

The expression of Cyclin E, p21WAF1/CIP1 and p53 was examined by using immunohistochemical method in normal epithelia (20), dysplastic epithelia (40) and laryngeal cancers (60).

RESULT

1. In normal epithelium, dysplastic squamous epithelium and in squamous cell carcinoma of the larynx, the positive immunostaining rate of Cyclin E protein was 5.0%(1/20), 20.0%(8/40) and 45.0%(27/60) respectively (P < 0.001), and p21WAF1/CIP1 protein was 95.0%(19/20), 75.0%(30/40) and 63.3%(38/60) respectively (P < 0.01), while the rate of p53 was 0, 30.0%(12/40) and 61.7%(37/60)(P < 0.001) respectively. 2. p21WAF1/CIP1 positive expression in highly, moderately and poorly differentiated carcinomas were 76.2%(16/21), 66.5%(19/29) and 30.0%(3/10) respectively (P < 0.05), p21WAF1/CIP1 protein expression was significantly associated with tumour cell differentiation. 3. The positive expression of Cyclin E closely related with the positive expression of p53 (P < 0.05). No correlation was found between p21WAF1/CIP1 expression and p53 expression.

CONCLUSION

1. Cyclin E and p53 could be an early molecular event in the carcinogenesis of larynx. 2. p21WAF1/CIP1 expression is associated with tumour cell differentiation. 3. The mutual mechanism of cell cycle regulators (Cyclin E, p21WAF1/CIP1 and p53) play an important role in the laryngeal carcinoma.

Physician-patient discussions of controversial cancer screening tests

BACKGROUND

Screening mammography for younger women and prostate-specific antigen (PSA) measurement have controversial benefits and known potential adverse consequences. While providing informed consent and eliciting patient preference have been advocated for these tests, little is known about how often these discussions take place or about barriers to these discussions.

METHODS

We administered a survey to medical house staff and attending physicians practicing primary care. The survey examined physicians' likelihood of discussing screening mammography and PSA testing, and factors influencing the frequency and quality of these discussions.

RESULTS

For the three scenarios, 16% to 34% of physicians stated that they do not discuss the screening tests. The likelihood of having a discussion was significantly associated with house staff physicians' belief that PSA screening is advantageous; house staff and attending physicians' intention to order a PSA test, and attending physicians' intention to order a mammogram; and a controversial indication for screening. The most commonly identified barriers to discussions were lack of time, the complexity of the topic, and a language barrier.

CONCLUSIONS

Physicians report they often do not discuss cancer screening tests with their patients. Our finding that physicians' beliefs and intention to order the tests, and extraneous factors such as time constraints and a language barrier, are associated with discussions indicates that some patients may be inappropriately denied the opportunity to choose whether to screen for breast and prostate cancer.

Phospholipase C is involved in kinetochore function in Saccharomyces cerevisiae

The budding yeast PLC1 gene encodes a homolog of the delta isoform of mammalian phosphoinositide-specific phospholipase C. Here, we present evidence that Plc1p associates with the kinetochore complex CBF3. This association is mediated through interactions with two established kinetochore proteins, Ndc10p and Cep3p. We show by chromatin immunoprecipitation experiments that Plc1p resides at centromeric loci in vivo. Deletion of PLC1, as well as plc1 mutations which abrogate the interaction of Plc1p with the CBF3 complex, results in a higher frequency of minichromosome loss, nocodazole sensitivity, and mitotic delay. Overexpression of Ndc10p suppresses the nocodazole sensitivity of plc1 mutants, implying that the association of Plc1p with CBF3 is important for optimal kinetochore function. Chromatin extracts from plc1Delta cells exhibit reduced microtubule binding to minichromosomes. These results suggest that Plc1p associates with kinetochores and regulates some aspect of kinetochore function and demonstrate an intranuclear function of phospholipase C in eukaryotic cells.

Expression and regulation of mRNAs for insulin-like growth factor-I receptor and LH receptor in corpora lutea

Relationship between insulin-like growth factor-I receptor (IGF-IR) and luteinizing hormone receptor (LHR) mRNA expression as well as their regulation was determined in rat corpora lutea (CL). In the CL of estrous cycle rat, LHR mRNA positive CL expressed high level of mRNA of IGF-IR. While the expression of LHR mRNA decreased on estrus, the CL still expressed relatively high level of IGF-IR mRNA. In pseudopregnant rat CL, the expression level of LHR mRNA was low on day 1, the most intense signals were detected on day 8, the signals of LHR mRNA became undetectable on day 14. In contrast to LHR expression, the high level of IGF-IR mRNA was observed in pseudopregnant CL of day 1, and thereafter its signals were detected from day 2 to day 14. Pregnant rat CL expressed both LHR and IGF-IR mRNAs. IGF-I stimulated LHR expression in CL. PGF(2alpha) inhibited expression of IGF-IR and LHR. PGE(2) negated the inhibiting effects of PGF(2alpha). These data suggest that IGF-I may be involved in regulating CL function, and maintaining CL structure through changes in expression of its receptors. Inhibited expression of IGF-IR by PGF(2alpha) may be part of mechanisms for regression of CL.

[The protective effects of cardiac ischemic preconditioning on lung in cardiac operation with cardiopulmonary bypass]

Twenty direct vision intracardial operation patients were divided into two groups randomly. After cardiopulmonary bypass, ten patients were treated with myocardial ischemic preconditioning. The aorta were clamped for 3 minutes and released for 3 minutes (Group IP). Another ten patients were not treated with ischemic preconditioning (Group C), only underwent 6 minutes cardiopulmonary bypass. Then the aorta were clamped and intracardial operation were done. The left atrium blood and lung tissue were collected just after thoractomy and half an hour after cardiac reperfusion in both groups.

RESULTS

(1) The numbers of polymorphonuclear (PMN) of the two groups were increased significantly after cardiopulmonary bypass (P < 0.01). (2) The number of PMN and SOD, PaO2 contents were significantly higher in Group IP than in Group C (P < 0.05). (3) The numbers of PMN in lung interstitum under microscopy were less in Group IP than in Group C. (4) MDA contents were less in Group IP than in Group C (P < 0.05). (5) Histological finding showed less damage in Group IP than in Group C. It is evident that cardiac ischemic preconditioning could protect lung against ischemia reperfusion injury. The possible mechanisms are that ischemic preconditioning inhibites the accumulation and activation of PMN in lung tissue and reduces the production of oxygen free radicals.

Inhibition of constitutively activated Stat3 signaling pathway suppresses growth of prostate cancer cells

Overexpression of interleukin 6, a downstream target of the GBX2 homeobox gene, has been linked to the progression of prostate cancer. The Janus kinase-signal transducers and activators of transcription signaling pathway transmits interleukin 6-mediated signals from cell surface receptors to the target genes in the nucleus and is critical in mediating cellular growth and differentiation. We demonstrate that cells derived from both rat and human prostate cancers have constitutively activated Stat3, with Stat3 activation being correlated with malignant potential. Blockade of activated Stat3 by ectopic expression of a dominant-negative Stat3 in human prostate cancer cells significantly suppresses their growth in vitro and their tumorigenicity in vivo. Furthermore, the Janus kinase inhibitor, tyrphostin AG490, inhibited the constitutive activation of Stat3 and suppressed the growth of human prostate cancer cells. These results indicate that activation of Stat3 signaling is essential in the progression of prostate cancer cells and suggest that targeting Stat3 signaling may yield a potential therapeutic intervention for prostate cancer.

Interleukin-6 induces prostate cancer cell growth accompanied by activation of stat3 signaling pathway

BACKGROUND

Interleukin-6 (IL-6) is a pleiotropic cytokine that regulates growth and differentiation of various types of malignant tumors, including prostate carcinomas. The levels of IL-6 are elevated in sera of patients with metastatic prostate cancer. In this study, we evaluate the role of IL-6 in the growth regulation of prostate cancer cells.

METHODS

Expression of IL-6 and its receptors in human prostate cancer cells was measured by ELISA and RT-PCR. The effects of IL-6 on cell growth were evaluated by ectopically expressing IL-6 cDNA into IL-6-negative LNCaP human prostate cancer cells. Stat3 DNA binding activities were analyzed by electromobility shift assay and supershift assay.

RESULTS

Expression of IL-6 was detected in the androgen-insensitive prostate cancer cell lines (i.e. , TSU, PC3, and DU145), but not in the androgen-sensitive LNCaP cell line. IL-6 receptors, including both IL-6-specific receptor alpha chain and gp130 signal transducer, are expressed in all human prostate cancer cell lines (i.e., LNCaP, TSU, PC3, and DU145). Overexpression of IL-6 by ectopically expressing IL-6 into IL-6-negative LNCaP human prostate cancer cells significantly increased clonogenic ability and cell proliferation in vitro compared to the IL-6-negative parental LNCaP cells and the antisense controls. This growth stimulation by IL-6 was accompanied by activation of the Stat3 signaling transduction pathway.

CONCLUSIONS

IL-6 is an autocrine growth factor for LNCaP human prostate cancer cells; the effects of IL-6 on prostate cancer cell growth are mediated through the Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling pathway.

Enhanced GBX2 expression stimulates growth of human prostate cancer cells via transcriptional up-regulation of the interleukin 6 gene

Previous studies demonstrated that the GBX2 homeobox gene is consistently overexpressed in cultured human prostate cancer cell lines. In this study, the human GBX2 cDNA was cloned and a quantitative reverse transcription-PCR method used to demonstrate that GBX2 mRNA expression is enhanced in approximately 70% of human prostate cancer tissues compared with normal human prostate tissues. Purified recombinant GBX2 protein binds specifically to an ATTA motif within the promoter of the interleukin 6 (IL-6) gene. Using an antisense approach, down-regulation of the expression of GBX2 correlated with decreased expression of IL-6 and an inhibition of tumorigenicity of PC3 human prostate cancer cells. In addition, in vitro growth of the antisense clones was partially restored by exogenous addition of recombinant IL-6 protein to the culture media. These data demonstrated that enhanced GBX2 expression results in a stimulation of malignant growth of prostate cancer cells and that part of this stimulation involves up-regulation in the transcription of the IL-6 gene.

Methylation of the CD44 metastasis suppressor gene in human prostate cancer

Previous studies demonstrated that CD44 is a metastasis suppressor gene for prostate cancer and that the expression of CD44 both at mRNA and protein levels is down-regulated during prostate cancer progression, with down-regulation being correlated with higher tumor grade, aneuploidy, and distant metastasis. In this study, we evaluated DNA hypermethylation as a potential mechanism accompanying this decreased CD44 expression in human prostate cancer. Nucleotide sequence analysis revealed a CpG island in the CD44 transcriptional regulatory region. We found that cytosine methylation of CD44 promoter occurs in CD44-negative prostate cancer cell line (i.e., LNCaP) but not in prostate cancer cell lines (i.e., TSU, PC3, and DU145) expressing this gene. In addition, we examined methylation status of CD44 in 84 matched normal and cancer prostate specimens. Hypermethylation of the 5' CpG island of CD44 gene was observed in 31 of 40 primary prostate cancer specimens, 3 of 4 distant organ site metastases obtained at autopsy from men who died of prostate cancer, and 4 of the 40 matched normal tissues. These results demonstrated that methylation of the 5' CpG island of CD44 gene is closely associated with transcriptional inactivation, resulting in a decreased expression of CD44 in human prostate cancer.

Suppression of the tumorigenicity of prostatic cancer cells by gene(s) located on human chromosome 19p13.1-13.2

BACKGROUND

In previous reports, we used microcell fusion-mediated chromosomal transfer to introduce normal human chromosomes into highly metastatic rat prostatic cancer cells to map the location of tumor and metastasis suppressor genes. The gene for prostate-specific antigen as well as several classes of genes, including cell adhesion molecules, previously demonstrated to be altered during prostate cancer progression, were mapped to human chromosome 19.

METHODS

A normal human chromosome 19 was introduced into Dunning-R3327 AT6.1 rat and TSU-prl human prostatic cancer cells by microcell-mediated chromosome transfer to test the suppressive effects of this chromosome on prostate cancer. Five independent hybrid clones from Dunning-R3327 AT6.1 rat prostatic cancer cells and four independent hybrid clones from TSU-pr1 human prostatic cancer cells were isolated, karyotyped, allelotyped, and analyzed for in vitro and in vivo growth characteristics.

RESULTS

Introduction of human chromosome 19 into both the rat and human prostatic cancer cells resulted in alteration of cell morphology in vitro and suppression of tumorigenicity in vivo in athymic nude mice. Highly polymorphic SSR2 markers mapped to human chromosome 19 were used to determine the portions of human chromosome 19 retained in the hybrids. These analyses identified a region localized on human chromosome 19p13.1-13.2 that is responsible for the tumor suppression of both rat and human prostatic cancer cells. The expression of several genes previously mapped to this human chromosome 19p13.1-13.2 region (i.e., ICAM-1, Notch3, and Stau) were analyzed to evaluate if they could be candidate suppressor genes for prostate cancer cell growth in vivo, but no expression patterns consistent with those predicted for a suppressor gene were observed.

CONCLUSIONS

Human chromosome 19p13.1-13.2 contains potential tumor suppressor gene(s) for prostate cancer.

A novel membrane-bound glutathione S-transferase functions in the stationary phase of the yeast Saccharomyces cerevisiae

The glutathione S-transferases (GSTs) represent a significant group of detoxification enzymes that play an important role in drug resistance in all eukaryotic species. In this paper we report an identification and characterization of the two Saccharomyces cerevisiae genes, GTT1 and GTT2 (glutathione transferase 1 and 2), coding for functional GST enzymes. Despite only limited similarity with GSTs from other organisms (approximately 50%), recombinant Gtt1p and Gtt2p exhibit GST activity with 1-chloro-2, 4-dinitrobenzene as a substrate. Both Gtt1p and Gtt2p are able to form homodimers, as determined by two hybrid assay. Subcellular fractionation demonstrated that Gtt1p associates with the endoplasmic reticulum. Expression of GTT1 is induced after diauxic shift and remains high throughout the stationary phase. Strains deleted for GTT1 and/or GTT2 are viable but exhibit increased sensitivity to heat shock in stationary phase and limited ability to grow at 39 degreesC.

Ischemic preconditioning enhances donor lung preservation in canine lung transplantation

OBJECTIVE

To prove the protective effect of lung ischemic preconditioning on enhancing the canine lung preservation and reducing allograft lung dysfunction after transplantation.

METHODS

Ten pairs of adult canines underwent left lung allotransplantation. Five donors were treated with ischemic preconditioning [their left hilus was clamped for 10 minutes and released for 15 minutes (Group IP)], and five donors were not treated with ischemic preconditioning (Group C). The donor lungs were flushed with 4 degrees C Euro-Collin's solution (ECS) and stored in the same solution for two and a half hour, then transplanted to the recipient canines, who were observed for one to two hours after transplantation. The lung venous blood of the recipient and the donor lung tissue were collected just after thoracotomy and one hour after reperfusion of the transplanted lung in both groups.

RESULTS

The number of polymorphonuclear (PMN) was significantly higher in Group IP than in Group C (P < 0.05). However, the number of PMN in lung interstitium under microscope was less in Group IP than in Group C. The thromboxane (TXB2), malondialdehyde (MDA) and mean pulmonary artery pressure (MPAP) contents were significantly lower in Group IP than in Group C (P < 0.05). The superoxide dismutase (SOD) and the lung venous blood oxygen tension (PvO2) contents were significantly higher in Group IP than in Group C (P < 0.05). Histological findings showed less damages in Group IP than in Group C.

CONCLUSIONS

The protective effect of ischemic preconditioning together with ECS flush and storage is superior to using ECS alone. The possible mechanisms may be that ischemic preconditioning inhibits the accumulation and activation of PMN in lung tissue and reduces the production of oxygen free radicals.