MicroRNA-520e suppresses growth of hepatoma cells by targeting the NF-κB-inducing kinase (NIK)

MicroRNAs (miRNAs) are small, non-coding RNAs that can act as oncogenes or tumor suppressor genes in human cancer. Emerging evidence indicates that deregulation of miRNAs contributes to the hepatocarcinogenesis. In the present study, we demonstrated that the levels of miR-520e were dramatically decreased in examined hepatoma cell lines and clinical hepatocellular carcinoma (HCC) tissues. Moreover, we found that DNA hypermethylation in the upstream region of miR-520e resulted in the downregulation of miR-520e. Next, we demonstrated that introduction of miR-520e dramatically suppressed the growth of hepatoma cells in vitro and in vivo, whereas silencing the expression of miR-520e by anti-miR-520e resulted in a promoted cell proliferation, suggesting that miR-520e may be a novel tumor suppressor. Further studies revealed that NF-κB-inducing kinase (NIK) was one of the direct target genes of miR-520e, as miR-520e directly bound to the 3'untranslated region of NIK, which reduced the expression of NIK at the levels of mRNA and protein. Moreover, silencing of NIK was able to inhibit the growth of hepatoma cells, similar to the effect of miR-520e overexpression on growth of hepatoma cells. Meanwhile, the knockdown of NIK expression reversed the enhanced proliferation mediated by anti-miR-520e. In addition, miR-520e significantly decreased the phosphorylation of ERK1/2 (p-ERK1/2) and depressed the transcriptional activity and nuclear translocation of nuclear factor κB (NF-κB) (p65). These results suggest that miR-520e suppresses the growth of hepatoma cells by targeting NIK involving the NIK/p-ERK1/2/NF-κB signaling pathway. Finally, we showed that the intratumoral injection with miR-520e was able to directly repress the growth of hepatoma cells in the nude mice. Thus, our finding provides new insight into the mechanism of hepatocarcinogenesis, indicating a therapeutic potential of miR-520e in the treatment of HCC.

The use of 18F-FDG PET/CT in colorectal liver metastases--comparison with CT and liver MRI

PURPOSE

We compared 18-fluoro-2-deoxyglucose ((18)F-FDG) positron emission tomography-CT (PETCT) with contrast-enhanced whole-body CT (ceCT) in identifying extrahepatic disease and with manganese dipyridoxyl diphosphate (Mn-DPDP) liver MRI for liver metastases in patients with colorectal liver metastases being considered for surgery.

METHODS

Sixty-five patients (median age 65 years; 42 men) with colorectal cancer and known or suspicious liver metastases and who underwent a PETCT, ceCT and Mn-DPDP MRI were identified. Results were retrospectively reviewed for extrahepatic disease on PETCT and ceCT, and for the presence and number of liver metastases on PETCT and Mn-DPDP MRI. Proof of metastases was based on histopathology or clinical/imaging follow-up, demonstrating disease progression or response.

RESULTS

PETCT identified unexpected extrahepatic disease not detected on ceCT, leading to change in surgical management in 17%. There were three other false-positive cases on PETCT. For liver metastases on a per-patient basis, the sensitivity and specificity of both PETCT and Mn-DPDP MRI were 98% and 100%, respectively. On a per-lesion basis, PETCT and MRI were discordant in 15% (10/66 scans). MRI correctly identified more sub-centimeter metastases in eight scans. PETCT correctly identified more metastases in one case and confirmed disease in one equivocal MRI.

CONCLUSION

PETCT has incremental benefit over conventional ceCT in identifying extrahepatic disease in metastatic colorectal cancer. PETCT has high sensitivity and specificity for the presence of liver metastases and should be included early in initial pre-surgical evaluation and could potentially guide the use of Mn-DPDP MRI. However, Mn-DPDP MRI is superior for small liver metastases and remains a prerequisite for surgical planning in patients with confined liver metastases.

6-Mercaptopurine, an activator of Nur77, enhances transcriptional activity of HIF-1alpha resulting in new vessel formation

Hypoxia-inducible factor-1alpha (HIF-1alpha) plays a central role in oxygen homeostasis. Previously, we reported that the orphan nuclear receptor Nur77 functions in stabilizing HIF-1alpha. Here, we demonstrate that 6-mercaptopurine (6-MP), an activator of the NR4A family members, enhances transcriptional activity of HIF-1. 6-MP enhanced the protein-level of HIF-1alpha as well as vascular endothelial growth factor (VEGF) in a dose- and time-dependent manner. The induction of HIF-1alpha was abolished by the transfection of either a dominant-negative Nur77 mutant or si-Nur77, indicating a critical role of Nur77 in the 6-MP action. The HIF-1alpha protein level remained up to 60 min in the presence of 6-MP when de novo protein synthesis was blocked by cycloheximide, suggesting that 6-MP induces stabilization of the HIF-1alpha protein. The fact that 6-MP decreased the association of HIF-1alpha with von Hippel-Lindau protein and the acetylation of HIF-1alpha, may explain how 6-MP induced stability of HIF-1alpha. Further, 6-MP induced the transactivation function of HIF-1alpha by recruiting co-activator cyclic-AMP-response-element-binding protein. Finally, 6-MP enhanced the expression of HIF-1alpha and VEGF, and the formation of capillary tubes in human umbilical vascular endothelial cells. Together, our results provide a new insight for 6-MP action in the stabilization of HIF-1alpha and imply a potential application of 6-MP in hypoxia-associated human vascular diseases.

Profiling of differentially expressed genes in human uterine leiomyomas

Uterine leiomyomas are very common benign tumors resulting in clinically serious gynecological problems in women of reproductive age. Approximately, 1% of leiomyosarcoma was reported to arise in a preexisting leiomyoma. However, the molecular basis of these tumors is poorly understood. To understand the molecular changes during leiomyoma development, we profiled differentially expressed genes in ten paired leiomyoma and normal myometrial tissues using cDNA microarray chip analysis. We identified 67 genes (27 overexpressed and 40 underexpressed) which were scored as differentially expressed at least twofold in at least eight of ten patients. Eighteen of 67 genes have been already reported to be differentially expressed without their established functions in uterine leiomyoma and others have never been reported. Subsequently, the relative expression levels of representative genes from identified 67 genes were confirmed by reverse-transcriptase polymerase chain reaction and immunohistochemistry and were found to be consistent with the microarray data. This study could provide a new insight into the understanding of leiomyoma and leiomyosarcoma.

Overexpression of Id-1 is significantly associated with tumour angiogenesis in human pancreas cancers

It has been suggested that Id-1 has a critical role in the tumour progression and aggressiveness of several human cancers. However, the clinicopathological and biological significance of Id-1 overexpression remains unclear in human primary cancer. To investigate the association between Id-1 expression and cell proliferation or tumour angiogenesis, we examined the cell cycle kinetic indices (the proliferation and apoptotic indices, PI and AI) and intratumoral microvessel density (MVD) in 65 human pancreatic cancers. We also investigated the relationship between its expression and various clinicopathological factors to determine the clinical significance of Id-1 overexpression. Out of a total 65 cases, 32 (49.3%) showed overexpression of Id-1 vs normal tissues. Id-1 expression was found to be significantly associated with MVD (P=0.002). In further analysis of subgroups with higher and lower Id-1 expression, tumours with higher Id-1 expression (scores 4 and 5) showed significantly higher MVD than tumours with lower expression of Id-1 (scores 2 and 3) (111.18+/-57.14 vs 64.13+/-28.19, P<0.001). However, no significant association was found between Id-1 overexpression and patient survival rate. No significant association was also found between Id-1 expression and cell cycle kinetic indices (PI or AI) in pancreatic cancer. Moreover, the overexpression of Id-1 protein was not correlated with any significant clinicopathologic factors. These findings indicate that Id-1 overexpression is closely related with tumour angiogenesis and a higher density of intratumoral vessel, but that it is not associated with a poorer prognosis of survival or a higher cell proliferative potential in human pancreatic cancer.

Inducible nitric oxide synthase (iNOS) immunoreactivity and its relationship to cell proliferation, apoptosis, angiogenesis, clinicopathologic characteristics, and patient survival in pancreatic cancer

BACKGROUND

The clinicopathological and biological significance of the expression of iNOS in pancreatic cancer remains unclear. The goal of this study was to determine the possible roles and clinical significance of iNOS expression in pancreatic cancer.

METHODS

Seventy-two pancreatic adenocarcinoma tissue specimens were obtained by surgical resection. We investigated the immunohistochemical expression of iNOS in 72 patients with pancreatic cancer with respect to variable clinicopathological characteristics, proliferation activity (assessed by Ki-67 expression), apoptosis (assessed by TUNEL stain), and microvessel density (assessed by CD34 expression; angiogenesis).

RESULTS

Immunohistochemical investigations demonstrated immunolabeling of tumor cells with anti-iNOS antibody. Positivity for iNOS was observed in 48/72 (66.7%). The expression of iNOS protein did not correlate with age, bilirubin, tumor marker, location, size, AJCC stage, differentiation, distant metastasis, or patient survival. No significant association was found between iNOS expression and proliferation or microvessel density in pancreatic cancer. Apoptotic index (AI) of positive iNOS expressions were significantly higher than negative expression (p < 0.001).

CONCLUSION

Inducible nitric oxide synthase (iNOS) is expressed by human pancreatic cancer, and its presence is positively correlated with apoptosis of cancer cells that could provide the basis for the development of therapeutic strategies in human pancreatic cancer.

Inhibition of rac1 reduces PDGF-induced reactive oxygen species and proliferation in vascular smooth muscle cells

In vascular smooth muscle cells, reactive oxygen species (ROS) were known to mediate platelet-derived growth factor (PDGF)-induced cell proliferation and NADH/NADPH oxidase is the major source of ROS. NADH/NADPH oxidase is controlled by rac1 in non-phagocytic cells. In this study, we examined whether the inhibition of rac1 by adenoviral-mediated gene transfer of a dominant negative rac1 gene product (Ad.N17rac1) could reduce the proliferation of rat aortic vascular smooth muscle cells (RASMC) stimulated by PDGF via decreasing intracellular ROS. RASMC were stimulated by PDGF (80 ng/mL) with or without N-acetylcysteine 1 mM or infected with 100 mutiplicity of infection of Ad.N17rac1. Intracellular ROS levels were measured at 12 hr using carboxyl-2', 7'-dichlorodihydrofluorescein diacetate confocal microscopy. At 72 hr, cellular proliferation was evaluated by cell number counting and XTT assay. Compared with control, ROS levels were increased by 2-folds by PDGF. NAC and Ad.N17rac1 inhibited PDGF-induced increase of ROS by 77% and 65%, respectively. Cell number was increased by PDGF by 1.6-folds compared with control. NAC and Ad.N17rac1 inhibited PDGF-induced cellular growth by 45% and 87%, respectively. XTT assay also showed similar results. We concluded that inhibition of rac1 in RASMCs could reduce intracellular ROS levels and cellular proliferation induced by PDGF.

Genetic alterations in hepatocellular carcinoma and intrahepatic cholangiocarcinoma

In the following study, we used comparative genomic hybridization (CGH) to screen and compare for genetic alterations of hepatocellular carcinoma (HCC) and intrahepatic choalgiocarcinoma (ICC). The studies showed distinctive features of genetic alterations between the two tumors. Characteristic abnormal changes for HCC were 1q gain and loss of 4q, 10q and 13q regions. In contrast, gains of 5p, 7p, 13q and 20q were more predominant in ICC. Losses of 16q, 17p, and 18q, and gain of 8q region showed a similar high frequency of incidence in both tumors. The most striking and different findings were 1q amplification in HCC and 20q gain in ICC. Our data indicate that ICC shows the pattern of genetic alterations similar to pancreatic and colorectal cancers. This suggests that the genetic alterations in tumorigenesis show a similar pattern depending on the origin of cells, not the organ.

A novel genetic island of meningitic Escherichia coli K1 containing the ibeA invasion gene (GimA): functional annotation and carbon-source-regulated invasion of human brain microvascular endothelial cells

The IbeA (ibe10) gene is an invasion determinant contributing to E. coli K1 invasion of the blood-brain barrier. This gene has been cloned and characterized from the chromosome of an invasive cerebrospinal fluid isolate of E. coli K1, strain RS218 (018:K1: H7). In the present study, a genetic island of meningitic E. coli containing ibeA (GimA) has been identified. A 20.3-kb genomic DNA island unique to E. coli K1 strains has been cloned and sequenced from an RS218 E. coli K1 genomic DNA library. Fourteen new genes have been identified in addition to the ibeA. The DNA sequence analysis indicated that the ibeA gene cluster was localized to the 98 min region and consisted of four operons, ptnIPKC, cglDTEC, gcxKRCI and ibeRAT. The G+C content (46.2%) of unique regions of the island is substantially different from that (50.8%) of the rest of the E. coli chromosome. By computer-assisted analysis of the sequences with DNA and protein databases (GenBank and PROSITE databases), the functions of the gene products could be anticipated, and were assigned to the functional categories of proteins relating to carbon source metabolism and substrate transportation. Glucose was shown to enhance E. coli penetration of human brain microvascular endothelial cells and exogenous cAMP was able to block the stimulating effect of glucose, suggesting that catabolic regulation may play a role in control of E. coli K1 invasion gene expression. Our data suggest that this genetic island may contribute to E. coli invasion of the blood-brain barrier through a carbon-source-regulated process.

A novel tumor-associated mucin of gastrointestinal carcinoma

PURPOSE

To identify a new tumor-associated antigen, a monoclonal antibody, SC142, was produced by immunizing mice with a stomach cancer cell line. The tumor specificity of mAb SC142 was studied by immunohistochemical staining, and the biochemical characteristics of this new gastrointestinal tumor-associated antigen were also studied.

METHODS

The expression of SC142-reactive antigen was investigated in various cancers by immunohistochemical staining. The SC142-reactive antigen was characterized by immunoblotting, sodium metaperiodate treatment assay, O-glycanase digestion assay, and lectin binding assay.

RESULTS

The SC142-reactive antigen was highly expressed in 78% of gastric cancers (29/37) and 87% of colon cancers (27/31). No normal colon or stomach tissues remote from the tumor were positive for the antigen. The antibody also reacted with other tumors of epithelial origin such as lung squamous cell cancer (2/4), breast ductal cancer (2/20), bladder transitional cell carcinoma (4/6), and uterine cancer (3/16). Western blot analysis of the antigen revealed glycoprotein(s) which migrated as a smear ranging from the origin of the gel to about the 80 kDa region. The reactivity of this antigen with SC142 was reduced by sodium metaperiodate treatment or O-glycanase digestion, but not by N-glycanase, suggesting that the epitope is an O-glycan. In lectin-binding assay, this antigen reacted only with wheat germ agglutinin but not with Ricinus communis agglutinin, Datura stramonium agglutinin, and Sambucus nigra agglutinin.

CONCLUSIONS

Our findings indicate that the antigen defined by SC142 is a tumor-associated antigen that could differentiate the gastrointestinal cancer cells from the normal cells. Therefore, SC142 may become a valuable tool for the immunohistochemical diagnosis and tumor immunoscintigraphy of the gastrointestinal cancer patients.

DNA sequence copy number aberrations associated with histological subtypes and DNA ploidy in gastric carcinoma

We have analyzed DNA sequence copy number aberrations (DSCNAs) and DNA ploidy by using comparative genomic hybridization and laser scanning cytometer in gastric carcinomas (GCs) to elucidate the genomic aberrations in relation to clinicopathological parameters. Thirty-two out of 33 cases showed one or more DSCNAs with a mean number of 11.7 per tumor. High-level gains were detected at 2p, 3q, 6p, 7p, 7q, 8q, 12p, 13q, 19q, and 20q. Frequency of gross genomic abnormalities and chromosome regions that have genomic aberrations were similar in both intestinal- and diffuse-type GCs, except aberrations at 8p, 9p, 12q, and 20q. The overall number of DSCNAs was significantly greater in DNA aneuploid tumors than that in DNA diploid tumors. We detected genomic aberrations characterized by histological subtype, tumor location, and DNA ploidy status: gain of 20q and losses of 8p and 9p in intestinal-type GCs, gains of 8p and 12q in diffuse-type GCs, gain of 20q in the lower third GCs, and loss of 5q, 9p, 10q, 16q, and 18q in DNA aneuploid GCs. Furthermore, 5q loss is associated with DNA aneuploidy (P = 0.0001) or the total number of losses (P = 0.001), gain + losses (P = 0.004), and high-level gains (P = 0.001) in GCs. Among these loci, chromosome 8p was unique. Gain of 8p was more common in diffuse-type GC, whereas loss of 8p was more frequently detected in intestinal-type GC. In conclusion, we describe chromosomal regions of 5q, 8p, and 20q, which are of interest for further investigation of GCs.

Comparative genomic hybridization analysis reveals 3q gain resulting in genetic alteration in 3q in advanced oral squamous cell carcinoma

We analyzed DNA sequence copy number aberrations (DSCNAs) in 17 primary oral squamous cell carcinomas (OSCCs) by comparative genomic hybridization. DSCNAs were detected frequently at 3q25-qter (7/17), Xp21 (5/17), and Xq12-q23 and 8q23-q24 (4/17), and losses were detected frequently at 13q21-q22 (5/17), 3p21-pter, 4p15-pter and 17p13 (4/17), and 8p22-pter and 9p21-pter (3/17). Four tumors showed amplifications of seven loci: 3q11-qter, 3q13, 3q26, 7q21-q22, 8q23-qter, 9p22-pter, and 12p11. The total number of DSCNAs was significantly greater in stage III and stage IV tumors than in stage I and stage II tumors (P=.008). Furthermore, 3q gain was detected preferentially in stage III and stage IV tumors (6/8) rather than in stage I and stage II tumors (1/9, P=.013). In our study, all tumors with gain of 3q also contained one or more loss(es) in common regions. On the other hand, all tumors with gain of 9p did not contain 3q gains. These observations indicate that gain of 3q and accumulation of DSCNAs are strongly associated with tumor progression in OSCC. Furthermore, 3q gain and loss of one or more additional loci in common aberration regions appears to be a group of DSCNs associated with dominant genetic pathways of leading to advanced OSCCs.

Characterization of the effect of hyperthermia on nanoparticle extravasation from tumor vasculature

The efficacy of novel cancer therapeutics can be hampered by inefficient delivery of agents to the tumor at effective concentrations. Liposomes have been used as a method to overcome some delivery issues and, in combination with hyperthermia, have been shown to increase drug delivery to tumors. This study investigates the effects of a range of temperatures (34-42 degrees C) and hyperthermia treatment scheduling (time between hyperthermia and drug administration as well as between consecutive hyperthermia treatments) on the extravasation of nanoparticles (100-nm liposomes) from tumor microvasculature in a human tumor (SKOV-3 ovarian carcinoma) xenograft grown in athymic nude mouse window chambers. Under normothermic conditions (34 degrees C) and at 39 degrees C, nanoparticles were unable to extravasate into the tumor interstitium. From 40 to 42 degrees C, nanoparticle extravasation increased with temperature, reaching maximal extravasation at 42 degrees C. Temperatures higher than 42 degrees C led to hemorrhage and stasis in tumor vessels. Enhanced nanoparticle extravasation was observed several hours after heating, decaying back to baseline at 6 h postheating. Reheating (42 degrees C for 1 h) 8 h after an initial heating (42 degrees C for 1 h) did not result in any increased nanoparticle extravasation, indicating development of vascular thermotolerance. The results of this study have implications for the application and scheduling of hyperthermia combined with other therapeutics (e.g., liposomes, antibodies, and viral vectors) for the treatment of cancer.

Preferential loss of 5q14-21 in intestinal-type gastric cancer with DNA aneuploidy

BACKGROUND

Little is known about the genetic changes associated with DNA ploidy in gastric cancer (GC). The aim of this study was to identify recurrent or specific chromosomal regions of DNA sequence copy number aberrations (DSCNAs) that might harbor genes associated with DNA aneuploidy in GC.

METHODS

We analyzed DSCNAs with comparative genomic hybridization and DNA ploidy by laser scanning cytometry in 16 primary intestinal-type GCs.

RESULTS

All GCs examined showed at least one DSCNA (loss or gain); eight were DNA diploid (DD) tumors and eight were DNA aneuploid (DA) tumors. The frequent (>30%) DSCNAs were loss of 5q14-21 and gains of 7p11-14, 8q, 20q, and Xq25-26. Recurrent amplifications (>10%) were detected at chromosomal regions 6p, 7p, and 13q. The overall number of DSCNAs was significantly greater in DA than in DD tumors (P = 0.006). Furthermore, the number of aberrations was clearly greater with 5q loss than without 5q loss (P = 0.002). Losses of 5q14-21, 9p21-pter, 16q, and 18q21-qter were preferentially detected in DA tumors.

CONCLUSION

The present observations indicate that there is a close relationship between DSCNA and DNA ploidy in intestinal-type GC and that gene(s) at 5q14-21, 9p21-pter, 16q, and/or 18q21-qter may play important roles in acquisition of DNA aneuploidy.

Efficacy of liposomes and hyperthermia in a human tumor xenograft model: importance of triggered drug release

The tumor drug concentrations, drug distributions, and therapeutic efficacies achieved by three fundamentally different liposomes, nonthermosensitive liposome (NTSL), traditional thermosensitive liposome (TTSL), and low temperature sensitive liposome (LTSL); free doxorubicin (DOX); and saline in combination with hyperthermia (HT) were directly compared in a human tumor xenograft model. NTSL is a nonthermosensitive liposome in the physiological temperature range, TTSL is a traditional thermosensitive liposome that triggers in the range of approximately 42-45 degrees C and releases drug over approximately 30 min, and LTSL is a new low temperature sensitive liposome that triggers in the range of approximately 39-40 degrees C and releases drug in a matter of seconds. Because of the different attributes of the liposomes, it was possible to delineate the relative importance of liposome drug encapsulation, HT cytotoxicity, HT-drug interaction, HT-induced liposomal delivery, and HT-triggered liposomal drug release in achieving antitumor activity. Athymic nude mice bearing the FaDu human tumor xenograft were given a single i.v. dose of 5 mg/kg of DOX (free drug or liposome encapsulated), and the tumors were then heated to either 34 degrees C or 42 degrees C for 1 h at 34 degrees C. All treatment groups were similar, achieving low concentrations of DOX (0-4.5 ng/mg). At 42 degrees C, the LTSL (25.6 ng/mg) achieved the highest DOX concentration (P < 0.04), but all three liposomal formulations (7.3-25.6 ng/mg) were higher than saline or DOX (0-0.7 ng/mg; P < 0.02). LTSL + HT was also the only group that resulted in significant amounts of DNA-bound DOX (silver nitrate-extractable fraction; P < 0.02). Tumor tissue sections were visualized for DOX fluorescence to investigate the local distribution of the drug in the tumor and confirm the relative drug concentrations based on fluorescence intensity. There was relatively little fluorescence seen with treatment groups at 34 degrees C. At 42 degrees C, the LTSL showed the most DOX fluorescence (P < 0.01), and the fluorescence, although not homogeneous, was pervasive throughout the tumor sections. Therapeutic efficacy of treatments was determined from tumor growth time. At 34 degrees C, the only treatment group significantly better than the saline group (9.8 days) was the NTSL group, with a growth time of 20.9 days (P < 0.02). At 42 degrees C, all three liposomal formulations were more efficacious than DOX. LTSL + HT had the longest growth time (51.4 days) and the most number of local controls at 60 days (six of nine tumors). With HT, the DOX concentrations and fluorescence were tightly correlated with tumor growth delay, indicating that adequate (increased) drug delivery can be predictive of therapeutic effect. Overall, the LTSL + HT group showed the largest DOX concentration, the highest and most pervasive DOX fluorescence, and the most antitumor effect. Thus, HT-triggered liposomal drug release may account for the largest differential therapeutic effect and demonstrates the importance of rapid drug release from the drug carriers at the tumor site.

Effects of tumor necrosis factor-alpha and interferon-gamma on expressions of matrix metalloproteinase-2 and -9 in human bladder cancer cells

We have investigated the effects of tumor necrosis factor-alpha (TNF-alpha) and interferon (INF-gamma), the potent Bacillus Calmette-Guerin (BCG)-induced cytokines on the production of MMP-2, MMP-9, TIMP-1, TIMP-2 and MT1-MMP in high grade human bladder cancer cell lines, T-24, J-82 and HT-1376 cell lines. MMP-2 expression and activity were decreased in T-24 cells treated with both cytokines in a dose dependent manner. However, J-82 cells treated with TNF-alpha and INF-gamma revealed dose dependent increases of MMP-9 expression and activity with similar baseline expression and activity of MMP-2. HT-1376 cells after exposure to TNF-alpha only enhanced the expression and activity of MMP-9. These results indicate that TNF-alpha and INF-gamma could regulate the production of MMP-2 or MMP-9 on bladder cancer cells and their patterns of regulation are cell specific. Furthermore, this diverse response of bladder cancer cells to TNF-alpha and INF-gamma suggests that BCG immunotherapy may enhance the invasiveness of bladder cancer in certain conditions with induction of MMPs.

Hyperthermia enables tumor-specific nanoparticle delivery: effect of particle size

The efficacy of novel cancer therapeutics has been hampered by the ability to deliver these agents to the tumor at effective concentrations. Liposomes have been used as a method to overcome some delivery issues and, in combination with hyperthermia, have been shown to increase drug delivery to tumors. Particle size has been shown to affect the delivery of liposomes, but it is not known how hyperthermia affects size dependence. This study investigates the effect of hyperthermia (42 degrees C) on the extravasation of different sized nanoparticles (albumin; 100-, 200-, and 400-nm liposomes) from tumor microvasculature in a human tumor (SKOV-3 ovarian carcinoma) xenograft grown in mouse window chambers. In this model (at 34 degrees C), no liposomes were able to extravasate into the tumor interstitium. Hyperthermia enabled liposome extravasation of all sizes. The magnitude of hyperthermia-induced extravasation was inversely proportional to particle size. Thus, at normothermia (34 degrees C), the pore cutoff size for this model was between 7 and 100 nm (e.g., liposomes did not extravasate). At 42 degrees C, the pore cutoff size was increased to >400 nm, allowing all nanoparticles tested to be delivered to the tumor interstitium to some degree. With hyperthermia, the 100-nm liposome experienced the largest relative increase in extravasation from tumor vasculature. Hyperthermia did not enable extravasation of 100-nm liposomes from normal vasculature, potentially allowing for tumor-specific delivery. These experiments indicate that hyperthermia can enable and augment liposomal drug delivery to tumors and potentially help target liposomes specifically to tumors.

Interferon-gamma-responsive neuronal sites in the normal rat brain: receptor protein distribution and cell activation revealed by Fos induction

Constitutive expression of the interferon-gamma receptor protein (IFN-gammaR), and the distribution of cells in which Fos, a marker of cell activation, is induced by intracerebroventricular administration of IFN-gamma, were studied in the rat brain by immunohistochemistry. IFN-gammaR immunopositivity was found in neuronal elements, which exhibited a selective distribution being concentrated in the piriform and entorhinal cortex, midline thalamus and medial hypothalamic structures, brainstem nociceptive relays (including the periaqueductal gray, the parabrachial nuclei and the caudal part of the spinal trigeminal nuclei), and circumventricular organs such as the median eminence and area postrema. IFN-gamma-induced Fos expression mostly corresponded to neuronal sites of receptor distribution. Because of its topographical distribution, it is suggested that activation of the IFN-gammaR in neurons may play a role to limit spread of infections in the brain and, in concert with other proinflammatory cytokines, to modulate adaptive responses to an antigen challenge mediated by the central nervous system.

A new temperature-sensitive liposome for use with mild hyperthermia: characterization and testing in a human tumor xenograft model

The single biggest challenge now facing drug delivery (for liposomes and indeed other carriers) is to initiate and produce release of the encapsulated drug only at the diseased site and at controllable rates. Our efforts have focused on developing a new thermal-sensitive drug delivery system, specifically for the local control of solid tumors. We describe here a new lipid formulation containing doxorubicin that has been optimized for both mild hyperthermic temperatures (39 degrees C to 40 degrees C) that are readily achievable in the clinic and rapid release times of drug (tens of seconds). This new liposome, in combination with mild hyperthermia, was found to be significantly more effective than free drug or current liposome formulations at reducing tumor growth in a human squamous cell carcinoma xenograft line (FaDu), producing 11 of 11 complete regressions lasting up to 60 days posttreatment.

Clofilium, a potassium channel blocker, induces apoptosis of human promyelocytic leukemia (HL-60) cells via Bcl-2-insensitive activation of caspase-3

We have demonstrated that clofilium, a potassium channel blocker, induces apoptosis on human promyelocytic leukemia (HL-60) cells. Cells treated with clofilium led to suppression of viability and proliferation in both time and concentration-dependent manners. Nuclear DAPI staining and electronmicroscopic examination revealed typical nuclear features of apoptosis in cells treated with clofilium that was further verified in DNA fragmentation analysis. Flow cytometry analysis with FITC-annexin V and propidium iodide (PI) revealed that apoptotic cell population with Annexin V+/PI- increased gradually from < 2% at 0 h, to 20% at 4 h and 29% at 16 h after exposure to 10 microM clofilium in HL-60 cells. Furthermore, fluorometric immunosorbent enzyme assay for activity of caspase-3 showed approximately a 10-fold increase of activity in cells treated with 10 microM of clofilium for 2-3 h compared with the basal level of its activity in untreated control cells. Immunoblotting analysis revealed proteolytic cleavage of caspase-3 and subsequent cleavage of PARP. However, there was no significant change of Bcl-2 and Bax proteins. These results indicate that clofilium exerts antiproliferative action and growth inhibition on HL-60 through induction of apoptosis which is mediated via Bcl-2-insensitive activation of caspase-3, and suggest chemotherapeutic and cytostatic potentials of this compound in human leukemias.

Induction of granulocytic differentiation in acute promyelocytic leukemia cells (HL-60) by 2-(allylthio) pyrazine

Induction of hematopoietic differentiation in human promyelocytic leukemia cells (HL-60) by new synthetic drugs or natural products has recently been recognized as a new strategy in the identification and testing of potential cancer chemopreventive and/or chemotherapeutic agents. 2-(Allythio) pyrazine (2-AP) is a pyrazine derivative of allysulfide, which has been suggested to be a potential cancer chemopreventive agent in previous in vivo and in vitro experiments. In the present study, we have investigated the inducing effect of granulocytic differentiation in HL-60 cells by 2-AP. Treatment of HL-60 cells with various concentrations of 2-AP (1-100 microM) for 7 days showed the induction of granulocytic differentiation following both morphological examination and NBT (nitroblue tetrazolium) testing (up to 40 and 52%, respectively). The expressions of bcl-2 and c-myc were down-regulated during granulocytic differentiation of HL-60 cells (up to 40%). The immunoblots for G1 cyclins in the G1-S phase transition (cyclin D1 and E) showed a progressive decrease of their expressions in both concentration- and time-dependent manners (up to 30 and 50%, respectively). These results suggest that 2-AP could induce the differentiation of HL-60 cells and might have potent cancer chemoprevention and/or chemotherapy roles in human leukemias.

Cyclin D1 overexpression is an indicator of poor prognosis in resectable non-small cell lung cancer

Cyclin D1 is one of the G1 cyclins that control cell cycle progression by allowing G1 to S transition. Overexpression of cyclin D1 has been postulated to play an important role in the development of human cancers. We have investigated the correlation between cyclin D1 overexpression and known clinicopathological factors and also its prognostic implication on resected non-small-cell lung cancer (NSCLC) patients. Formalin-fixed and paraffin-embedded tumour tissues resected from 69 NSCLC patients between stages I and IIIa were immunohistochemically examined to detect altered cyclin D1 expression. Twenty-four cases (34.8%) revealed positive immunoreactivity for cyclin D1. Cyclin D1 overexpression is significantly higher in patients with lymph node metastasis (50.0% vs 14.4%, P = 0.002) and with advanced pathological stages (I, 10%; II, 53.8%; IIIa, 41.7%, P = 0.048; stage I vs II, IIIa, P = 0.006). Twenty-four patients with cyclin D1-positive immunoreactivity revealed a significantly shorter overall survival than the patients with negativity (24.0 +/- 3.9 months vs 50.1 +/- 6.4 months, P = 0.0299). Among 33 patients between stages I and II, nine patients with cyclin D1-positive immunoreactivity had a much shorter overall survival (29.7 +/- 6.1 months vs 74.6 +/- 8.6 months, P = 0.0066). These results suggest that cyclin D1 overexpression is involved in tumorigenesis of NSCLCs from early stage and could be a predictive molecular marker for poor prognosis in resectable NSCLC patients, which may help us to choose proper therapeutic modalities after resection of the tumor.

Hyperthermia and liposomes

Hyperthermia and liposomal drug delivery are treatment modalities that have been used to treat cancer over the last two decades. More recently, the two therapies have been used together in an attempt to exploit their mutual interactions against cancer. The goal of this review is to explore the literature related to combined hyperthermia and liposomal drug delivery for cancer therapy. The motivation behind combining hyperthermia and liposomal drug delivery is discussed from a physical chemical and physiological standpoint. Two types of therapeutic ratios were calculated for in vivo studies from across the literature. These ratios compared the results obtained from hyperthermia and liposomes to hyperthermia and free drug as well as to liposomes without hyperthermia. These two therapeutic ratios were applied to both tumour drug uptake and tumour growth delay studies. In all studies reviewed, hyperthermia in combination with liposomal drug showed an enhanced therapeutic effect compared to either treatment modality alone or hyperthermia and free drug. Future work needs to be focused on optimizing thermosensitive liposomes and understanding the effect of thermal dose on liposomal drug delivery. Though not currently used in the clinic, this combination therapy seems to hold great promise towards improving current cancer therapeutic regimens.

2-(allylthio)pyrazine suppresses the growth and proliferation of human promyelocytic leukemia (HL-60) cells via induction of apoptosis

Apoptosis or programmed cell death is a highly organized physiologic process of not only maintaining homeostasis but also selectively eliminating damaged or abnormal cells. Apoptotic destruction of predisposed cells may reduce the proportion of cells available for malignant progression. Thus, pharmacologic manipulation of apoptotic pathway is regarded as a novel strategy in cancer chemoprevention as well as therapy. 2-(Allylthio)pyrazine (2-AP), a pyrazine derivative of allylsulfide synthesized for use as a chemoprotective agent, has been shown to protect against experimental carcinogenesis and mutagenesis. The present study examined the capability of 2-AP to induce apoptosis in cultured human promyelocytic leukemia (HL-60) cells. Treatment of HL-60 cells with 2-AP led to suppression of viability and proliferation in a concentration-dependent manner. Microscopic examination of the treated cells revealed typical morphological features of apoptosis, such as nuclear fragmentation and chromatin condensation. Furthermore, cells treated with 2-AP exhibited internucleosomal DNA fragmentation. Flow cytometric analysis of HL-60 cells exposed to 2-AP showed appearance of a distinct peak representing the subdiploid cell population. 2-AP treatment decreased the ratio of anti-apoptotic Bcl-2 to the death stimulating protein Bax, which may account for the molecular basis of apoptosis-inducing activity of this chemopreventive organosulfur derivative.

Resveratrol, an antioxidant present in red wine, induces apoptosis in human promyelocytic leukemia (HL-60) cells

Resveratrol, a triphenolic stilbene present in grapes and other plants, has striking antioxidant and anti-inflammatory activities which have been considered to be responsible for the beneficial effects of red wine consumption on coronary heart disease. Recent studies reveal that resveratrol can inhibit each step of multistage carcinogenesis. However, the molecular mechanisms underlying anti-tumorigenic or chemopreventive activities of this phytochemical remain largely unknown. In the present work, we have found that resveratrol reduces viability and DNA synthesis capability of cultured human promyelocytic leukemia (HL-60) cells. The growth inhibitory and antiproliferative properties of resveratrol appear to be attributable to its induction of apoptotic cell death as determined by morphological and ultrastructural changes, internucleosomal DNA fragmentation, and increased proportion of the subdiploid cell population. Resveratrol treatment resulted in a gradual decrease in the expression of anti-apoptotic Bcl-2. These results, together with previous findings, suggest the cancer therapeutic as well as chemopreventive potential of resveratrol.

Bcl-2 and p53 expressions in invasive bladder cancers

We investigated the Bcl-2 and P53 protein expressions in 89 patients with bladder cancers using immunohistochemical analysis. In superficial tumors, the times of tumor recurrence and progression were significantly shorter in the P53-positive group than in the negative group (p < 0.005, p < 0.05, respectively). In invasive tumors, the disease-specific actuarial survivals were significantly lower in the P53 and Bcl-2-positive groups (p <0.05, p < 0.025, respectively). In multivariate analysis, overexpression of p53 and Bcl-2 had independent prognostic value for survivals in invasive tumor, while disease-free survival was related independently to overexpression of p53 in superficial tumor. The results of our assessment for chemoeffectiveness revealed that the patients with Bcl-2-positive tumors had significantly lower response rates than those with Bcl-2-negative tumors (p < 0.05). We conclude that p53 expression is an independent, poor prognostic marker in invasive tumors as well as in superficial tumors and that overexpression of Bcl-2 is independently associated with a reduced-survival in patients with invasive tumors. These prognostic differences related to P53 and Bcl-2 expression in invasive bladder cancers may be partly due to chemo- or radio-sensitivity in relation to apoptotic process.

Expression of Wilms tumor gene (WT1) in children with acute leukemia

Wilms tumor gene (WT1) expression occurs in various malignancies including adult leukemia. WT1 expression was studied in children with acute leukemia according to morphological types and immunophenotypes. RT-PCR was used to examine relative level of WT1 transcripts from the peripheral blood of 15 children diagnosed with acute leukemia: 12 acute lymphoblastic leukemias (ALLs) and 3 acute myelogenous leukemias (AMLs); 8 ALLs newly diagnosed, 2 ALLs in first marrow relapse, 2 ALLs in remission over 2 years, 2 AMLs newly diagnosed, and 1 AML in second marrow relapse. Six healthy adult volunteers were studied for controls. WT1 was detectable in 7 out of 10 ALLs and all 3 AMLs, but not in 2 ALLs in remission and the controls. The expression levels were higher for AMLs than for ALLs. According to the types of ALL, WT1 was detectable in 2 out of 2 non-T group II, 4 out of 6 non-T group III, but not in one CD20+ non-T group IV, while one T-ALL showed a relatively high level. WT1 expression was detectable more frequently in ALL-L2 than in ALL-L1 and with higher levels for ALL-L2. WT1 expression was frequently noted in children with acute leukemia. The results suggest that WT1 transcripts may prove to be a significant tumor marker, possibly as an MRD monitor in evaluating remission status and early relapse, and may also prove to be useful in predicting outcomes in acute leukemia in children.

p53 mutations and human papillomavirus DNA in oral squamous cell carcinoma: correlation with apoptosis

Forty-two oral squamous cell carcinomas (SCCs) were analysed for p53 mutations and human papillomavirus (HPV) infection to examine the prevalency of these factors and correlation with apoptotic index (AI; number of apoptotic cells per 100 tumour cells) of the tumour tissue. In polymerase chain reaction (PCR)-Southern blot analysis, HPV DNAs were detected from 22 out of 42 SCCs (52%) with predominance of HPV-16 (68%). p53 mutations in exons 5-8, screened by nested PCR-single-strand conformation polymorphism (PCR-SSCP) analysis, were observed in 16 of 42 tumours (38%). The state of the p53 gene did not show any correlation with HPV infection. The terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL) method was used for detection of apoptotic cells. The mean AI was 2.35, ranging from 0.31 to 6.63. SCCs associated with p53 mutation had significantly lower AI than those without p53 mutation (P < 0.01), whereas no difference in AI was found between SCCs with and without HPV infection. The results of this study confirmed that HPV infection and/or p53 mutations are implicated, but are not mutually exclusive events, in carcinogenesis of oral SCC and also showed that decrease in apoptosis is more closely related to p53 mutation than HPV infection.

Expression of cyclin dependent kinase inhibitor p21WAF1 alone and in combination with p27KIP1 shows prognostic value in gastric carcinoma

Evidence suggests that multiple molecular events, including alteration of cell cycle regulators are involved in the development and progression of gastric carcinoma. Recently, it has been reported that the expression of p21 and p27, integrating the effects of one or more cell cycle regulators, consequently, acting as a single indicator of several possible cell cycle gene alterations is associated with tumor suppression. In the present study, we studied the immunohistochemical expression of p21 and p27 in gastrectomy specimens from 84 patients with gastric adenocarcinoma, and analysed its correlation to clinicopathologic data, including patients survival. Loss of p21 and p27 expression was noted in 45 (53.6%) and 44 (52.4%) of the 84 gastric carcinoma tissues, respectively. The expression of p21 was significantly correlated with histological type (p= 0.005), recurrence (p=0.002) and death (p=0.002) after surgery, and p27 expression (p=0.001). Kaplan-Meier survival plots showed p21 negative group (p= 0.0014) or both p21 and p27 negative group (p=0.0048) was significantly poorer in overall survival than both p21 and p27 positive or one of both positive group. Our results suggest that the status of p21 and p27 expression in immunohistochemical stain may be a useful prognostic marker of gastric carcinoma.

Beta-adrenergic receptor kinase-1 acutely regulates PTH/PTHrP receptor signalling in human osteoblastlike cells

To investigate whether G protein-coupled receptor kinases (GRKs) are involved in the regulation of the PTH/PTHrPR, we have established mutant SaOS-2 cells which stably overexpress (> 10-20-fold) a dominant negative form of the beta-adrenergic receptor kinase-1 (beta ARK-1). Acute (< or = 2 h) incubation with hPTH (1-34) induced significantly less (by up to 50%) downregulation of the PTH/PTHrPR in beta ARK-1 mutant SaOS-2 cells than observed in wild-type cells. Pretreatment of wild-type cells with PTH for 2 h induced homologous cAMP desensitisation to a second challenge with PTH, while the effect was blunted by up to 60% in beta ARK-1 mutant cells. We conclude that activation of beta ARK-1 (or a closely related GRK) is a critical component of the acute phase (< or = 2 h) of PTH-induced receptor downregulation and homologous cAMP desensitisation of the PTH/PTHrPR.

Overexpression of cyclin D1 correlates with early recurrence in superficial bladder cancers

Cyclin D1 is a cell cycle regulator essential for G1 phase progression and is frequently overexpressed in several human tumour types as a consequence of gene amplification or chromosomal rearrangements. We analysed the expression of cyclin D1 in 75 patients with transitional cell carcinoma (TCC) to investigate the possible relationship between its expression and clinical outcome as well as histopathological findings using the immunohistochemical method. We observed strong staining (++, > 50% positive cells) for cyclin D1 in 19 cases (25.3%) and weak staining (+, 5-50% positive cells) in 19 cases (25.3%). Overexpression of cyclin D1 was not associated with tumour invasion. No significant association was found between overexpression of cyclin D1 and tumour grade (P > 0.05). We assessed the differences of disease-free interval in superficial tumours and actuarial survival probability in invasive tumours according to the status of cyclin D1 expression. Tumours with (++) staining for cyclin D1 recurred much more rapidly than (-) and/or (+) staining tumours (P < 0.01 for - vs ++; P < 0.05 for + vs ++). However, overexpression of cyclin D1 was not associated with a shortened overall survival of patients with invasive tumours (P < 0.1). These results suggest that genetic alteration of cyclin D1 appears to be an early event in the tumorigenesis of bladder TCC and is associated with early recurrence in superficial tumours.

Distinct tyrosine phosphorylation sites in ZAP-70 mediate activation and negative regulation of antigen receptor function

Biochemical and genetic evidence has implicated two families of protein tyrosine kinases (PTKs), the Src- and Syk-PTKs, in T- and B-cell antigen receptor signaling. ZAP-70 is a member of the Syk-PTKs that associates with the T-cell antigen receptor and undergoes tyrosine phosphorylation following receptor activation. Three tyrosine residues, Tyr-292, -492, and -493, have been identified as sites of phosphorylation following T-cell antigen receptor engagement. Utilizing ZAP-70- and Syk-deficient lymphocytes (Syk-DT40 cells), we provide biochemical and functional evidence that heterologous trans-phosphorylation of Tyr-493 by a Src-PTK is required for antigen receptor-mediated activation of both the calcium and ras pathways. In contrast, cells expressing mutations at Tyr-292 or -492 demonstrate hyperactive T- and B-cell antigen receptor phenotypes. Thus, phosphorylation of ZAP-70 mediates both activation and inactivation of antigen receptor signaling.

Phosphorylation of SLP-76 by the ZAP-70 protein-tyrosine kinase is required for T-cell receptor function

Two families of tyrosine kinases, the Src and Syk families, are required for T-cell receptor activation. While the Src kinases are responsible for phosphorylation of receptor-encoded signaling motifs and for up-regulation of ZAP-70 activity, the downstream substrates of ZAP-70 are unknown. Evidence is presented herein that the Src homology 2 (SH2) domain-containing leukocyte protein of 76 kDa (SLP-76) is a substrate of ZAP-70. Phosphorylation of SLP-76 is diminished in T cells that express a catalytically inactive ZAP-70. Moreover, SLP-76 is preferentially phosphorylated by ZAP-70 in vitro and in heterologous cellular systems. In T cells, overexpression of wild-type SLP-76 results in a hyperactive receptor, while expression of a SLP-76 molecule that is unable to be tyrosine-phosphorylated attenuates receptor function. In addition, the SH2 domain of SLP-76 is required for T-cell receptor function, although its role is independent of the ability of SLP-76 to undergo tyrosine phosphorylation. As SLP-76 interacts with both Grb2 and phospholipase C-gamma1, these data indicate that phosphorylation of SLP-76 by ZAP-70 provides an important functional link between the T-cell receptor and activation of ras and calcium pathways.

Molecular mechanisms of agonist-induced desensitization of the cloned mouse kappa opioid receptor

Prolonged exposure of opioid receptors to agonists can cause desensitization, a cellular event linked to tolerance. Although evidence exists for mu and delta opioid receptor desensitization, much less information is available concerning the in vitro regulation of kappa opioid receptors because no cell lines exist that specifically express this class of opioid receptor. Recently we have cloned the mouse kappa opioid receptor. After expression in COS-7 cells, this protein exhibits the pharmacological specificity of a kappa 1 receptor and mediates agonist inhibition of cAMP formation. Continuous exposure of COS-7 cells expressing the kappa receptor to the agonist trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]- benzeneacetamide methanesulfonate salt (U50,488) reduces the specific binding of the kappa-selective agonist [3H]U69,593. Furthermore, the potency of U50,488 to inhibit the binding of the opiate antagonist [3H]naloxone to the kappa receptor is reduced. However, total specific binding of [3H]naloxone is not altered, indicating that short-term (2-4 hr) agonist treatment of the kappa receptor reduces the affinity of the receptor for agonists but does not reduce the density of kappa receptors. The reduction in affinity of the kappa receptor for agonists is dependent on the time of agonist exposure and is reversible. The reduced affinity of the receptor for agonists is associated with kappa receptor desensitization, because kappa receptor-mediated inhibition of cAMP formation is lost in cells pretreated with U50,488. The desensitization of the kappa receptor is dependent on the time and concentration of agonist treatment, is blocked by the kappa-selective antagonist nor-binaltorphimine and is reversible.(ABSTRACT TRUNCATED AT 250 WORDS)

A beta-adrenergic receptor kinase dominant negative mutant attenuates desensitization of the beta 2-adrenergic receptor

The beta-adrenergic receptor kinase (beta ARK) specifically phosphorylates the activated form of the beta 2-adrenergic receptor (beta 2AR) and related G protein-coupled receptors. To further elucidate the role of beta ARK in receptor desensitization, we generated a beta ARK dominant negative mutant by converting an invariant lysine residue in the protein kinase catalytic domain to an arginine. Expressed and purified beta ARK-K220R was able to inhibit wild type beta ARK phosphorylation of the beta 2AR in vitro. When stably transfected into human bronchial epithelial BEAS-2B cells, beta ARK-K220R promoted a > 2-fold increase in beta-agonist-stimulated cAMP production without affecting beta 2AR sequestration. In contrast, beta ARK-K220R had no effect on the desensitization of the prostaglandin E2 receptor response in BEAS-2B cells. These findings directly demonstrate a role for beta ARK in desensitization of the beta 2AR in intact cells and establish the potential utility of using dominant negative mutants to elucidate the substrate specificity of G protein-coupled receptor kinases.

Response of recurrent giant cell myocarditis in a transplanted heart to intensive immunosuppression

A 35-year-old man developed giant cell myocarditis resulting in severe congestive cardiac failure. He needed urgent orthotopic cardiac transplantation despite maximal doses of inotropes and augmentation with an intra-aortic balloon pump. The patient presented with rhythm disturbances and echocardiographically diminished ventricular function at subsequent follow-up. Biopsies then taken revealed recurrence of myocarditis in the transplanted heart. Investigations revealed no obvious cause for the myocardial granulomas nor any evidence of systemic granulomatous disease. The patient received, in addition to maintenance cyclosporin A and azathioprine, high doses of corticosteroids which resulted in complete resolution of the inflammatory process and no recurrence has been detected to date. This case shows that giant cell myocarditis can recur in the transplanted heart despite routine immunosuppression with azathioprine and cyclosporin A and that additional treatment with high dose corticosteroids is effective in causing regression of the inflammatory process.

[A study on pharmacokinetics of 3H-mitoxantrone in experimental animals]

Mitoxantrone (DHAQ) we studied is a new semisynthetic antitumor drug prepared in China. This paper reports the pharmacokinetic studies of 3H-mitoxantrone in mice by liquid scintillation. The results showed that the decline of radioactivity in the plasma was a biphasic curve after intramuscular and intravenous injection in rats. The adsorption of 3H-DHAQ was ready and complete after intramuscular injection, it was widely distributed in body tissues. The concentration order of various organs was liver greater than intestine greater than kidney greater than lung greater than heart greater than muscles greater than brain. The elimination of the drug was slow, T1/2 was 42.56 h. In 72 h after administration the cumulative excretion of radioactivity in urine was 7% of the total dose, while that in feces was 43%. The main forms of the drug in urine were its metabolites.

Middle-ear disease in Indians of the Mount Currie Reservation, British Columbia

Complete otological examinations, including audiograms, were carried out on 504 British Columbia Indians of the Mount Currie Reservation. Of these, 79 were found to have evidence of current middle ear pathology, while 226 were known to have had previous disease. Among 364 subjects who could be formally tested, 112 had a 15-decibel or greater hearing loss in the speech frequencies. Among these Indians, middle-ear disease began early in life and recurrences were frequent. The prevalence of aural disease was related to poor social conditions, family history and presence of nasal discharge. No other relationships could be demonstrated, and there was no evident benefit from adenotonsillectomy. No secretory otitis or otosclerosis and almost no sensorineural high-tone hearing loss were discovered.