Boromycin abrogates bleomycin-induced G2 checkpoint

The DNA-damaging agent bleomycin arrests the cell cycle at the G2 phase of Jurkat cells defective in the G1 checkpoint, and microtubule-acting colchicine arrests it at the M phase. Boromycin itself, an actinomycete metabolite, showed no effect on the cell cycle status of Jurkat cells at least up to 340 nM. However, the compound (3.4-340 nM) was found to abrogate bleomycin-induced G2 arrest even at 3.4 nM, resulting in a drastic decrease in cells at the G2 phase and increase in cells at the subG1 phase. On the other hand, boromycin did not show any effect on the colchicine-induced M phase arrest in Jurkat cells, nor on the cell cycle status of the bleomycin-treated or -untreated HUVEC, normal cells conserving both G1 and G2 checkpoints. Furthermore, boromycin potentiated anti-tumor activity of bleomycin in scid mice inoculated with Jurkat cells. These data suggest that boromycin disrupts the cell cycle at the G2 checkpoint of cancer cells selectively, leading to sensitization of cancer cells to anti-cancer reagents.     

Pancreatic mass lesions associated with raised concentration of IgG4

Autoimmune pancreatitis (AIP) is a recognized benign disease characterized by irregular narrowing of the pancreatic duct, swelling of parenchyma, lymphoplasmacytic infiltration and fibrosis, and a favorable response to corticosteroid treatment. In this condition, the whole pancreas is diffusely affected. Recently, however, a few cases with locally affected lesions were reported, with some of them showing features similar to cancer. We reviewed 138 patients with pancreatic mass lesion, of which 17 were not initially diagnosed despite examinations. Serum IgG4 levels were elevated in seven of them. Their biopsy specimens had a similar appearance to those of AIP. We considered that they should be diagnosed as AIP or conditions related to AIP. Among the 10 patients without elevated IgG4, 4 patients were diagnosed as pancreatic cancer after follow-up, 1 presented with an islet cell tumor, 1 presented AIP with sclerosing cholangitis, and the other 4 had chronic pancreatitis.     

Sepsis alters vessel contraction by adrenoceptor-induced nitric oxide and prostanoid

BACKGROUND: Alpha-adrenergic agents contract vascular smooth muscle (VSM) and stimulate endothelial release of secondary factors which modulate VSM contraction. Our study examined constrictor prostanoid (cPN) and nitric oxide (NO) as secondary factors which could alter alpha-1 adrenoceptor-mediated contraction during sepsis. METHODS: Sepsis was induced in rats by inoculation of an implanted sponge with Escherichia coli and Bacteroides fragilis. Aortic rings at 24 h from septic (n = 21) and control (n = 21) rats were suspended in physiological salt solution (PSS) with or without blockers to NO (N(G)-monomethylarginine), cPN (mefenamic acid, MFA), or thromboxane A2 (SQ29548). Contraction dose-response curves were generated to determine maximal contraction force (F(max)) and pD2 (sensitivity) to phenylephrine in each experimental group. RESULTS: Sepsis increased F(max) to phenylephrine (PHE) (1.18 vs 0.90 g, SEM 0.0703). COX inhibition reduced the F(max) in control (0.63 vs 0.90 g, SEM 0.0675) but not in septic animals (1.19 vs 1.18 g, SEM 0.0433). TXA2 receptor inhibition did not alter F(max) in control (1.017 vs 0.973 g, SEM 0.0959) or septic animals (1.28 vs 1.12 g, SEM 0.0823). NOS inhibition enhanced the F(max) in both nonseptic (2.03 vs 0.83 g, SEM 0.0523) and septic rats (1.96 vs 1.15 g, SEM 0.0526), but did less so in the septic animals. CONCLUSIONS: PHE-induced F(max) is determined by a balance between PHE-stimulated VSM alpha-adrenoceptor activity, and PHE-stimulated endothelial release of cPN and NO. Sepsis enhances total PHE-induced F(max) by increasing VSM alpha-adrenoceptor activity and reducing PHE-stimulated endothelial release of dilator NO. Sepsis abolishes the PHE-stimulated endothelial release of cPN. PHE-stimulated cPN is not thromboxane A2, but could be a nonprostanoid dilator in the lipoxygenase (HETE) or cytochrome P450 (EET) pathways.     

Identification of benzo(a)pyrene diol epoxide-binding DNA fragments using DNA immunoprecipitation technique

Benzo(a)pyrene diol epoxide (BPDE), an active metabolite of the tobacco carcinogen benzo(a)pyrene, can induce p53 gene mutation, down-regulate retinoic acid receptor beta, and increase cyclooxygenase-2 expression in human epithelial cells. However, it remains unknown whether these effects are direct or indirect. To investigate the direct effects of BPDE on gene expression, we used our newly developed DNA immunoprecipitation technique to identify and clone BPDE-binding DNA fragments. A total of 67 fragments were sequenced and grouped into four categories after their sequences were blasted in the GenBank database: (a). 15 fragments matched known gene sequences; (b). 24 matched expressed sequence tag clones; (c). 22 matched genomic DNA of unknown genes; and (d). 6 clones did not show any homology with GenBank sequences known to date. The 67 fragments include DNA repair and apoptosis-related genes, zinc finger protein, cellular enzymes, expressed sequence tag clones, and CpG islands. These data further demonstrate that BPDE-induced gene alterations are important events in carcinogenesis and that the identification of the resulting clones may help us to better understand the mechanisms of BPDE-induced carcinogenesis.     

Macrocystic serous cystadenoma of the pancreas: case report

We report a case of macrocystic serous cystadenoma of the pancreas. The lesion consisted of a large main cyst and several small cysts, and each cyst showed high intensity on T1-weighted and very high intensity on T2-weighted magnetic resonance images. High-intensity cyst contents may be a characteristic, if not a specific, finding of macrocystic serous cystadenoma of the pancreas. Received: 24 April 2000/Accepted: 31 May 2000     

Post-initiation effects of a super critical extract of propolis in a rat two-stage carcinogenesis model in female F344 rats

Post-initiation modifying effects of dietary administration of a super critical extract of propolis on major organs were examined using a two-stage carcinogenesis model. Groups of 21 or 22 F344 female rats were treated sequentially with 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN, i.g.), 7,12-dimethylbenz[a]anthracene (DMBA, i.g.), 1,2-dimethylhydrazine (DMH, s.c.) and N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN, in drinking water) during the first 3 weeks for initiation, and then administered diet containing 0.1 or 0.01% propolis for 33 weeks. Further groups were treated with the carcinogens alone, 0.1% propolis alone or basal diet alone. All surviving animals were killed at week 36, and major organs were examined histopathologically for development of preneoplastic and neoplastic lesions. The incidence and multiplicity of mammary carcinomas were significantly decreased by the 0.1 and 0.01% propolis treatments. In the urinary bladder, the incidence of PN hyperplasia but not tumors was, in contrast, significantly increased by 0.1% propolis. Similarly, the number and area of glutathione S-transferase placental form (GST-P)-positive liver foci were significantly elevated with this high dose. The results indicate that a low dose of a super critical extract of propolis may find application as a potent chemopreventor of mammary carcinogenesis.     

Distribution of alpha1L-adrenoceptors in canine prostate: characterization by quantitative autoradiography

Our aim was to determine the distribution of alpha1L-adrenoceptors in canine prostate by an autoradiographic technique using [3H]JTH-601 (an alpha1L-adrenoceptor antagonist) and [3H]JTH-601-G1 (an active metabolite of JTH-601). Prostates were removed from three male beagle dogs. Several slices of the specimens were incubated with 5 nM of [3H]JTH-601, [3H]JTH-601-G1 and [3H]tamsulosin (an alpha1A-adrenoceptor antagonist). For macroscopic autoradiography, visualization was performed using an imaging plate and image-analyser. To examine microscopic localization of binding sites, preparations were exposed, developed and fixed. Specific binding of [3H]JTH-601 and [3H]JTH-601-G1 was observed diffusely throughout the entire interstitium on macroscopic autoradiography. Specific binding of [3H]tamsulosin was also recognized although the binding was weaker than that of [3H]JTH-601. On microscopic autoradiograms, the grains of each ligand were mainly distributed on smooth muscle. These results indicate morphologically that specific binding sites of JTH-601 and JTH-601-G1 exist in canine prostate, suggesting the distribution of alpha1L-adrenoceptors in this tissue, in addition to alpha1A-adrenoceptors.     

Expression of metalloproteinase-2 (gelatinase A) in labial salivary glands of patients with Sj?gren's syndrome with HTLV-I infection.

OBJECTIVE: To determine whether gelatinase A (MMP-2) plays a significant role in the pathogenesis of Sj?gren's syndrome (SS) with or without HTLV-I infection. METHODS: We examined 24 patients with SS (14 HTLV-I-seropositive and 8 HTLV-I-seronegative). Labial salivary gland tissue samples were analysed immunohistochemically using anti-MMP-2 monoclonal antibodies. RESULTS: In normal salivary glands, MMP-2 expression was not detected. All biopsy samples of 8 SS patients with HTLV-I-associated myelopathy (HAM) and 3 of 6 HTLV-I-seropositive SS patients without manifestation of HAM stained positively for MMP-2. However, the other samples were negative for MMP-2. CONCLUSION: Our study showed the MMP-2 expression in labial salivary glands of HTLV-I seropositive SS patients, especially in all SS patients with HAM. The presence of MMP-2 in the salivary glands of these patients suggests that it may play a role in cellular infiltration and destruction in salivary glands of SS.