Pharmacokinetic study of penetration of meropenem into pleural effusion in patients with pleurisy

Complication by secondary infection is observed in not only bacterial pleurisy but also other pleurisy, and the appropriate administration of antibacterial agents is necessary. It is very important to secure a smooth penetration of systemically administered antibacterial agents to pleural effusion in infection therapy. In this study, we investigated the pharmacokinetics of a carbapenem antibiotic, meropenem (MEPM), in blood and pleural effusion in patients with an accumulation of pleural effusion caused by pleurisy, who underwent placement of an indwelling thoracic drain and received intravenous drip administration of MEPM for pneumonia or other respiratory tract infection. The blood pharmacokinetic parameters of MEPM after an intravenous drip administration of 0.5 g MEPM in six patients were: area under the blood concentration-time curve (AUCx), 37.9 +/- 6.2 (hr.mg/L); volume of distribution (Vd), 27.3 +/- 4.4 (L); total clearance (CLtotal), 13.4 +/- 1.8 (L/hr); elimination half life (t1/2), 0.50 +/- 0.08 (hr-1); and elimination rate constant (kel), 1.42 +/- 0.22 (hr). The pharmacokinetic parameters in pleural effusion were: AUCx, 35.7 +/- 7.1 (hr.mg/L); mean retention time (MRT), 5.00 +/- 3.25 (hr); variance of retention time (VRT), 29.9 +/- 44.6 (hr2); kel, 0.34 +/- 0.27 (hr-1); and t1/2, 3.14 +/- 2.36 (hr). The penetration rate calculated from the ratio of pleural concentration to blood concentration in each patient was 46.5 +/- 26.1%, showing good penetration comparable or superior to those of other antibacterial agents previously reported. From these results, it was suggested that MEPM was rapidly penetrated to the pleural effusion and was retained for a more prolonged time in the pleural effusion than in the blood of patients with accumulated pleural effusion, and it suggested the usefulness of MEPM in antibacterial therapy for patients with pleurisy causing accumulation of pleural effusion.     

Effect of single intracerebroventricular injection of alpha-interferon on monoamine concentrations in the rat brain.

The effect of a single intracerebroventricular (i.c.v.) injection of alpha-IFN on levels of central monoamines and their metabolites in six brain regions (frontal cortex, striatum, hypothalamus, hippocampus, mid brain and medulla) of the rat was investigated. Wistar rats (n=10) were decapitated 2 h after i.c.v. injection of alpha-IFN. The brain tissues were homogenized, and monoamine concentrations were measured by high-performance liquid chromatography with an electrochemical detector. The levels of 5-hydroxytryptamine (5-HT) were significantly reduced in the frontal cortex in a dose-dependent manner, and the levels of both 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) were reduced in the mid brain and the striatum. The levels of noradrenaline (NA) were also significantly reduced in a dose-dependent manner in the frontal cortex. Some neurophysiological changes that affect activity of the noradrenergic or/and the serotonergic neuron system may occur during IFN therapy.     

Radiotherapy for bone metastases from hepatocellular carcinoma and pancreas cancer

There are few reports on the treatment for bone metastases from hepatocellular carcinoma (HCC) and pancreas cancer. We evaluated the therapeutic effects of radiotherapy (RT) in patients with bone metastases from these cancers. Bone metastases from HCC are typically lytic and expansive. We evaluated 13 patients with 16 bone metastases from HCC undergoing RT (30-40 Gy, median 39 Gy) in our department from September 2002 to December 2004. Tumor regression was evaluated by CT or MRI. More than 50% tumor regression was achieved in 4 of 16 lesions (25%). Pain relief was achieved in 12/13 (92%). The median survival was 7 months (95% confidence interval [CI], 4-10 months), and the 6-month and 12-month local control rates were 81% and 67%, respectively. For patients with a limited life expectancy, standard dose RT is appropriate, however,with more than one year life expectancy, investigation employing dose escalation or combination with surgery or TAE is needed. Thirteen patients with 18 bone metastases from pancreas cancer received RT (20-30 Gy, median 30 Gy) from September 2002 to March 2005. The median survival was 3 months (95% CI, 1-6 months). Pain relief was achieved in 12/13 (92%). The prognosis of patients with bone metastases from pancreas cancer is still very poor, and a single fraction or short fraction schedule RT is appropriate.     

Cycloprodigiosin hydrochloride, H(+)/CL(-) symporter, induces apoptosis and differentiation in HL-60 cells

Cycloprodigiosin hydrochloride (cPrG * HCl), a novel H(+)/Cl(-) symporter, induces acidification of the cytosol and leads to apoptosis in rat and human liver cancer cells. In the present study, the effect of cPrG * HCl on a promyelocytic leukemia cell line (HL-60) was examined. cPrG * HCl lowered intracellular pH and induced apoptosis through up-regulation of Fas ligand, activation of stress-activated protein kinase (SAPK/JNK) and caspase. Apoptosis induced by cPrG * HCl was strongly suppressed when a cell-permeable weak base, imidazole, was present, indicating that cytosol acidification introduced by cPrG * HCl triggered caspase activation, leading to apoptosis. Concomitantly, cell differentiation into monocyte was also induced by cPrG * HCl both morphologically and functionally. However, the cPrG * HCl-induced differentiation was not suppressed by addition of imidazole, indicating that the differentiation process is unrelated to cytosol acidification. Further, the differentiation induced by cPrG * HCl was blocked by tyrosine kinase inhibitors (lavendustin A and HMA) but unaffected by the inhibitors of A-kinase (H-89) or C-kinase (H-7). Taken together, these findings suggest that cPrG * HCl, through apoptosis and differentiation induction, may be useful in leukemia treatment.     

Rapamycin, a specific inhibitor of the mammalian target of rapamycin, suppresses lymphangiogenesis and lymphatic metastasis

Tumor lymphangiogenesis is now known to play a causal role in lymph node metastasis, and thus its inhibition would have great significance for the prevention of lymph node metastasis in cancer therapy. VEGF-C has recently been identified as a key molecule that involved in tumor lymphangiogenesis and lymphatic metastasis. However, the expressional regulation of VEGF-C is not fully understood. We investigated the role of mTOR, which is a downstream kinase of the phosphatidylinositol 3-kinase/Akt pathway, and the MAPK family (MEK1/2, p38, and JNK) in the regulation of VEGF-C and VEGF-A expression in B13LM cells, a lymphatic metastasis-prone pancreatic tumor cell line. We also investigated the antilymphangiogenic effect of rapamycin, a specific inhibitor of mTOR in vivo using male BALB/c nu/nu mice. VEGF-C expression was inhibited by the inhibitors for mTOR, p38, and JNK, but not by the inhibitor for MEK1/2, whereas VEGF-A expression was inhibited by all four of these inhibitors. The serum starvation-induced expression of VEGF-C was inhibited by rapamycin, whereas that of VEGF-A was incompletely inhibited. The metastatic experiment in vivo demonstrated that the number and the area of lymphatic vessels in the primary tumors were significantly decreased by rapamycin. Finally, the lymph node metastasis was significantly suppressed in rapamycin-treated mice. Our results suggest that mTOR, p38, and JNK play important roles in VEGF-C expression, and that rapamycin has an antilymphangiogentic effect and exerts the expected inhibition of lymphatic metastasis.     

PRTFDC1, a possible tumor-suppressor gene, is frequently silenced in oral squamous-cell carcinomas by aberrant promoter hypermethylation

Array-based comparative genomic hybridization (array-CGH) has good potential for the high-throughput identification of genetic aberrations in cell genomes. In the course of a program to screen a panel of oral squamous-cell carcinoma (OSCC), cell lines for genomic copy-number aberrations by array-CGH using our in-house arrays, we identified a 3-Mb homozygous deletion at 10p12 in 1 of 18 cell lines (5.6%). Among seven genes located within this region, expression of PRTFDC1 mRNA was not detected in 50% (9/18) or decreased in 5.6% (1/18) of OSCC cell lines, but detected in normal oral epithelia and restored in gene-silenced OSCC cells without its homozygous loss after treatment with 5-aza-2'-deoxycytidine. Among 17 cell lines without a homozygous deletion, the hypermethylation of the PRTFDC1 CpG island, which showed promoter activity, was observed in all nine cell lines with no or reduced PRTFDC1 expression (52.9%). Methylation of this CpG island was also observed in primary OSCC tissues (8/47, 17.0%). In addition, restoration of PRTFDC1 in OSCC cells lacking its expression inhibited cell growth in colony-formation assays, whereas knockdown of PRTFDC1 expression in OSCC cells expressing the gene promoted cell growth. These results suggest that epigenetic silencing of PRTFDC1 by hypermethylation of the CpG island leads to a loss of PRTFDC1 function, which might be involved in squamous cell oral carcinogenesis.     

Mechanisms underlying the attenuation of endothelium-dependent vasodilatation in the mesenteric arterial bed of the streptozotocin-induced diabetic rat

Experiments were designed to investigate the mechanisms underlying the diabetes-related impairment of the vasodilatations of the perfused mesenteric arterial bed induced by acetylcholine (ACh) and K(+). In streptozotocin (STZ)-diabetic rats, the ACh-induced endothelium-dependent vasodilatation was attenuated. The dose-response curves for ACh in control and diabetic rats were each shifted to the right by N(G)-nitro-L-arginine (L-NOARG) and by isotonic high K(+) (60 mM). The ACh dose-response curves under isotonic high K(+) were not different between control and diabetic rats. We also examined the vasodilatation induced by K(+), which is a putative endothelium-derived hyperpolarizing factor (EDHF). The mesenteric vasodilatation induced by a single administration of K(+) was greatly impaired in STZ-induced diabetic rats. Treatment with charybdotoxin plus apamin abolished the ACh-induced vasodilatation but enhanced the K(+)-induced response in controls and diabetic rats. After pretreatment with ouabain plus BaCl(2), the ACh-induced vasodilatation was significantly impaired and the K(+)-induced relaxation was abolished in both control and diabetic rats. The impairment of the endothelium-dependent vasodilatation of the mesenteric arterial bed seen in STZ-induced diabetic rats may be largely due to a defective vascular response to EDHF. It is further suggested that K(+) is one of the endothelium-derived hyperpolarizing factors and that the vasodilatation response to K(+) is impaired in the mesenteric arterial bed from diabetic rats.     

Antibody‐dependent cellular cytotoxicity toward neuroblastoma enhanced by activated invariant natural killer T cells

Anti‐ganglioside GD2 antibodies mainly work through antibody‐dependent cellular cytotoxicity (ADCC) and have demonstrated clinical benefit for children with neuroblastoma. However, high‐risk neuroblastoma still has a high recurrence rate. For further improvement in patient outcomes, ways to maximize the cytotoxic effects of anti‐GD2 therapies with minimal toxicity are required. Activated invariant natural killer T (iNKT) cells enhance both innate and type I acquired anti‐tumor immunity by producing several kinds of cytokines. In this report, we investigated the feasibility of combination therapy using iNKT cells and an anti‐GD2 antibody. Although some of the expanded iNKT cells expressed natural killer (NK) cell markers, including FcγR, iNKT cells were not directly associated with ADCC. When co‐cultured with activated iNKT cells, granzyme A, granzyme B and interferon gamma (IFNγ) production from NK cells were upregulated, and the cytotoxicity of NK cells treated with anti‐GD2 antibodies was increased. Not only cytokines produced by activated iNKT cells, but also NK‐NKT cell contact or NK cell‐dendritic cell contact contributed to the increase in NK cell cytotoxicity and further IFNγ production by iNKT cells and NK cells. In conclusion, iNKT cell‐based immunotherapy could be an appropriate candidate for anti‐GD2 antibody therapy for neuroblastoma.     

Gemcitabine enhances rituximab‐mediated complement‐dependent cytotoxicity to B cell lymphoma by CD20 upregulation

Although rituximab, a chimeric monoclonal antibody that specifically binds to CD20, has significantly improved the prognosis for diffuse large B cell lymphoma (DLBCL), one‐third of DLBCL patients demonstrate resistance to rituximab or relapse after rituximab treatment. Thus, a novel approach to rituximab‐based treatment is likely to be required to improve the efficacy of DLBCL treatment. As complement dependent cytotoxicity (CDC) is a key mechanism mediating rituximab's tumoricidal activity, rituximab binding to CD20 on tumor cells is a critical factor for effective rituximab‐based treatments against DLBCL. We found that gemcitabine (GEM), but not lenalidomide (LEN) or azacitidine (AZA), can upregulate CD20 expression in TK and KML‐1 cells, two human DLBCL cell lines. Treatment of TK and KML‐1 cells with GEM enhanced CD20 expression at both the mRNA and protein levels. CD20 upregulation by GEM treatment was accompanied by increased rituximab binding to CD20. In TK cells, GEM treatment synergistically increased rituximab‐mediated CDC activity in a dose‐dependent manner. In KML cells, GEM treatment also induced upregulation of complement regulatory proteins, possibly leading to resistance to CDC. Treatment with LEN, a drug that did not upregulate CD20, did not enhance rituximab‐mediated CDC activity. GEM treatment activated nuclear factor‐kappa B (NF‐kB) signaling in these cells. Furthermore, a specific inhibitor to NF‐kB suppressed GEM‐induced CD20 upregulation, indicating that GEM‐induced NF‐kB activation is closely associated with CD20 upregulation. These results suggest that when used in combination, GEM might enhance the antitumor efficacy of rituximab against DLBCL due to its unique ability to upregulate CD20.