Proceedings of the National Science Council, Republic of China. Part B, Life sciences最新文献

This study, using the MBT-2 murine bladder tumor model, mainly investigated the role of interleukin-12 (IL-12) in the specific antitumor immune response of a tumor-bearing host when systemically administrated after surgery. Day 17 tumor-bearing mice (D17TBM) along with non-tumor bearing naive mice were treated with daily intraperitoneal (i.p.) injection of IL-12 (0.25 microg/mouse) from day 18 to day 24 for a total of 7 doses. Their splenocytes were obtained on Day 31 for natural killer cells (NK), lymphokine activated killer cells (LAK) and cytotoxic T lymphocyte (CTL) activity assay and lymphocyte subsets phenotypic analysis. The tumor suppression effect of systemic IL-12 administration was evaluated based on the tumor outgrowth of the higher number of tumor cells rechallenged 24 hours after resectioning of the primary tumor. After evaluation on Day 31, the result of in vitro cytotoxicity assay revealed that systemic administration of IL-12 mainly enhanced the splenic LAK and CTL activities in non-tumor-primed naive mice, and the NK activity in tumor-primed D17TBM, respectively. However, in vivo administration of IL-12 with or without IL-2 failed to upgrade the proportions of either CD4+ CD44+ or CD8+ CD44+ T cells subsets in the spleens and regional inguinal lymph nodes (LNs) of both the D17TBM and naive mice. However, the splenic CD8+ CD44+ T-cell subset in the IL-12-treated D17TBM increased prominently after further culturing in the presence of IL-2 400 units/ml plus IL-12 25 ng/ml for 4 days. The fact that systemic administration of IL-12 significantly suppressed the outgrowth of Day-18 challenged tumor cells, especially in D17TBM, clearly indicates that the established specific antitumor immunity in tumor-primed D17TBM was efficiently augmented. From the results of this study, we conclude that, after surgical resection of a primary tumor, systemic administration of IL-12 can be an effective adjuvant therapy because it demonstrates a significant augmentation effect on the tumor-specific immune response in the tumor-primed host.

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder with expansion of trinucleotide CAG repeats in the coding region of the gene. Expansion of the repeat tract beyond the normal range produces gene products with extended polyglutamine tracts. In this study, we analyzed the distribution of the CAG repeats in the DRPLA alleles in a normal Taiwanese population. We observed 15 different alleles and found that the range of the CAG repeat number was from 7-21. The most frequent allele contained 15 CAG repeats that represented 20% of the total analyzed alleles, followed by the 17 repeats (15.8%). The heterozygosity rate of this locus was 88%. Twelve parents-to-children transmissions of the DRPLA alleles in a Machado-Joseph disease family appeared to be normal without any alteration of the CAG repeat numbers. Phenotypes of DRPLA overlapped those of autosomal dominant cerebellar ataxia (ADCA). In order to identify DRPLA patients in Taiwan, we screened six autosomal dominant cerebellar ataxia patients without expansion in known spinocerebellar ataxia genes. All six patients had the repeat numbers within the normal range; thus, the possibility of DRPLA could be excluded.

Tea is one of the most widely consumed beverages, second only to water. Many experimental researches in laboratory animals demonstrated that tea components had an inhibitory effect on carcinogenesis at a number of organ sites. The inhibitory effects of tea against carcinogenesis have been attributed to the biologic activities of the polyphenol fraction in tea. This review summarizes experimental data on chemopreventive effects of tea polyphenols in various tumor bioassay systems. Many laboratory studies have demonstrated the inhibitory effects of green tea polyphenols, especially (-)-epigallocatechin-3-gallate (EGCG), on carcinogenesis in animals models. The majority of these studies have been conducted in mouse skin tumor models, where tea polyphenols were used either as oral feeding in drinking water or in direct local application. Most studies used 12-O-tetradecanoylphorbol-13-acetate (TPA) or ultraviolet (UV) radiation as the tumor promoter and found anticarcinogenic effects caused by green tea polyphenols. Black tea was also found to be effective, although the activity was weaker than that of green tea in some experiments. Other studies showed that black tea polyphenols-theaflavins exhibited stronger anticarcinogenic activity than did EGCG. Caffeine in tea was also important for tea to prevent tumorigenesis. The molecular mechanisms of the cancer chemopreventive effects of tea polyphenols are not completely understood. They are most likely related to the mechanisms of biochemical actions of tea polyphenols, which include antioxidative activities, modulation of xenobiotic metabolite enzymes and inhibition of tumor promotion. In addition, we have also proposed that tea polyphenols function as cancer chemopreventive agents through modulation of mitotic signal transduction. However, the molecular mechanisms involved in this modulation need further investigation.

Anthralin and its derivatives containing a variety of simple or functionalized aliphatic and aromatic substituents are of special interest in research on psoriasis. In this connection, 10-arylthio-1,8-dihydroxy-9(10H)-anthracenones were synthesized and examined by means of mass spectrometry. In general, the molecules in question fragmented upon electron impact into ions at m/z 225 (C-S bond cleavage and charge retention at the anthralin component) and into ions of unknown structure at m/z 226, requiring H-migration from the S-bound substituent R into the anthralin moiety. Since mass spectrometry methods furnished us elegant, matchless means of tracing the amounts of material in the analysis, especially in the case of physiologically active compounds, we decided to use mass spectrometry procedures for unequivocal identification and purity determination of 10-arylthio-anthralins.

A total of 65 blood samples collected from Holstein cattle were employed for DNA extraction. Genomic DNA were amplified by means of random amplified polymorphic DNA (RAPD). One hundred and one random primers (Operon kits OPAA, OPAO, OPAV, OPC, OPE and OPA-06) were used for polymerase chain reactions (PCR). The PCR products were size fractionated by means of electrophoresis in agarose gel, transferred to a nylon membrane, and then hybridized with a alpha-32P-labeled microsatellite probe for random amplified microsatellite polymorphism (RAMPO) analysis. All the primers produced many amplification patterns in RAMPO fingerprints, but only OPE-01 (5'-CCCAAGGTCC-3') yielded a male-specific strong signal. Among the 65 cases, the specific band could be observed in the RAMPO fingerprints of the 24 male samples but not in the 41 female samples. Therefore, this specific band is peculiar to male cattle.

The purpose of this study was to investigate the effect of acetic acid-extracted bone proteins on human periodontal ligament fibroblasts (hPF) with respect to mitogenic and cell attachment promoting activity. Alveolar bone was harvested from healthy donors and subjected to 0.5 M acetic acid extraction, dialysis and lyophilization, and gel filtration. Promotion of cell attachment and stimulation of DNA synthesis by the crude extract and gel-filtrated fractions were studied in cultured hPE Many protein components, varying in molecular weight from 10-14 to 120 kDa, were detectable in 10% SDS-PAGE of the extract. Gel filtration of bone extract disclosed four fractions with molecular weights of 55, 34, 29 and 19-20 kDa. Both the 34 and 55 kDa fractions at a concentration of 5 microg/ml, but not the 29- or 19-20 kDa fractions, were found to promote cell attachment while only the 55 kDa fraction (5 microg/ml) stimulated DNA synthesis of hPF, Both mitogenic activity and the promotion of the cell attachment by gel-filtrated active fractions were resistant to thermal treatment (70 degrees C) and pH (4 to approximately 8) changes. These findings suggest that acetic acid extract of alveolar bone may contain components which are capable of modulating cell attachment and mitogenesis of hPF.

Previously, we have used the biochemical receptor binding method to investigate whether down-regulation of the opioid receptor is a mechanism for morphine tolerance, and we were led to a negative conclusion. In the current study, we further used immunohistochemistry to reinvestigate this issue. Male Sprague-Dawley rats (250-300 g) were chronically treated with morphine s.c. for 2, 4 or 6 days, using an escalating dosage paradigm (5-45 mg), which resulted in a 1.8 to 4.0-fold increase in AD50. Rat brains were removed, frozen, coronally sectioned (14 microm) and processed for mu- or delta-opioid receptor immunohistochemistry using the Avidin-Biotin Complex (ABC) method. No significant decrease in mu-opioid receptor (MOR) immunodensity was found in most of the brain regions, which were enriched with MOR after chronic treatment with morphine except for the anteroventral thalamic nucleus in the ventrolateral part (AVVL). No significant change in delta-opioid receptor (DOR) immunodensity after chronic treatment with morphine was found either. Therefore, our conclusion is that down regulation of opioid receptors may not be an important mechanism for morphine tolerance.

It has been suggested that the septum plays an inhibitory role in the behavioral function. Recent work has shown that the septum is heterogeneous from the neuroanatomical perspective. The present study examined the water intake of rats lesioned with kainic acid (0.5 microg/0.5 microl/site) on three septal subregions: anterior medial (MSa), posterior medial (MSp), and lateral (LS) sites. Drinking volume was enhanced mostly in rats with the MSp lesion, and so was locomotor activity. However, these two measures were not significantly correlated. This polydipsia induced by MSp lesion was also found in a chronic domain. Another experiment further determined the dipsogenic effects of polyethylene glycol (PEG; 20%) and hypertonic saline (1 M NaCl) in MSp lesioned rats. Water intake increased significantly after administration of the hypertonic saline treatment, but not after injection of PEG. However, this disparity approached a nonsignificant level 8 hr after thirst challenges were conducted. In addition to revealing septal hyperdipsia. these data suggest that the septal subareas can be functionally heterogeneous in drinking behavior. The dipsogenic response profiles for the cellular and extracellular thirst challenges could be differentially affected by kainate lesion in the MSp.

Porcine reproductive and respiratory syndrome (PRRS) is a highly contagious disease that affects pigs of all ages worldwide. One of the key features of PRRS pathogenesis is the prolonged viremia in which the virus coexists with antibody. Prolonged viremia raises the concern that porcine products and boar semen may be contaminated by residues of the PRRS virus serving as vehicles for spreading of the virus. To answer this question, we sampled blood, muscles and viscera organs from market pigs slaughtered using an on-the-rail system and utilized a direct reverse transcription-polymerase chain reaction (RT-PCR) to detect residual viral RNA. We found that the overall seropositive rate of the market pigs was 85.4% (205/240), yet only 7.9% (11/140) of the blood samples contained detectable amounts of virus residues, and all tested carcase specimens (n = 472) were negative. The clinical sensitivity of this PCR varied with the tissues tested, with 5 TCID50 per 50 microliters of serum, as determined by means of a spiking experiment. Semen samples (n = 38) of clinically healthy seropositive and seronegative boars were collected from six herds which were routinely subjected to artificial insemination for production purposes. None of the seminal plasma or sperm-rich fractions contained PCR detectable virus residues. However, the possibility of PRRS virus present in semen cannot be totally excluded. We conclude that in naturally infected albeit clinically healthy pigs, the amounts of PRRS virus residues in carcases or semen are minimal. Thus, the risk of these products causing animal health hazards is low.

Further to our work on the feasibility of application of photodynamic therapy (PDT) to the canine prostate, this study evaluates the biological responses of the prostate and adjacent vital structures with meso-tetra-(m-hydroxylphenyl) chlorin (mTHPC) or aluminum disulfonated phthalocyanine (AlS2Pc) based PDT as a preparatory step for clinical trials. Skin photosensitivity was not particularly problematic if light protection could be implemented properly for 2 weeks following sensitization. Prostate PDT was well tolerated by the experimental animals with only minor physical distress. mTHPC was more powerful than AlS2Pc in terms of prostate lesions induced. A large portion of prostate tissue could be destroyed by PDT with 4 punctures. Physical distress was probably caused by severe urethral irritation and aching from acute swelling of the prostate. Although the voiding condition normalized within 10 days, regeneration of urethral epithelium was not complete until 3-4 weeks after PDT. Improper placement of laser fiber caused extensive ecchymosis of the retroperitoneal organs. The biological significance of PDT induced hyperemia in the periprostatic structures remains poorly defined. Neither periprostatic nerve damage nor rectal lesions were seen in dogs receiving either mTHPC or AlS2Pc. Glandular atrophy with papillary cystic regeneration of the prostate was the most prominent finding 90 days after PDT. The glandular architecture was well preserved because the interlobular collagens were less affected than the cellular components of the glands. Our study suggests that PDT with mTHPC and AlS2Pc is safe and promising for necrosing a substantial amount of prostate tissue. The completeness of treatment and long-term therapeutic effectiveness for prostate cancer, however, remains to be determined through further investigation.