Insulin-like growth factor I,but not neurotrophin-3, sustains Akt activation and provides long-term protection of immature oligodendrocytes from glutamate-mediated apoptosis

Glutamate toxicity is a major contributor to death of oligodendroglia in diverse CNS disorders. The goal of these studies was to investigate the mechanisms of glutamate toxicity and trophic factor protection of the immature pro-oligodendroblast (pro-OL). Glutamate induced time- and dose-dependent DNA fragmentation and caspase-3 activation in pro-OLs. IGF-I or NT-3, but not CNTF, prevented apoptosis of pro-OLs by 24 h via a PI3-kinase-dependent pathway; however, only IGF-I protected pro-OLs from glutamate toxicity through 48 h. Long-term protection of pro-OLs by IGF-I was correlated with sustained activation of Akt while NT-3 activation of Akt was transient. The differential ability of IGF-I and NT-3 to maintain Akt activation was due to differences in receptor activation and stability. In the presence of NT-3, TrkC phosphorylation and protein expression decreased significantly while activation of the IGF-IR was maintained in the pro-OLs in the presence of IGF-I.     

Sex-related hormonal influences on pain and analgesic responses

Considerable evidence indicates sex-related differences in pain responses and in the effectiveness of various analgesic agents. Specifically, females are at greater risk for experiencing many forms of clinical pain and are more sensitive to experimentally induced pain relative to males. Regarding analgesic responses, nonhuman animal studies indicate greater opioid analgesia for males, while a limited human literature suggests the opposite. Though the mechanisms underlying these effects remain unclear, the influence of gonadal hormones on nociceptive processing represents one plausible pathway whereby such sex differences could emerge. The present article reviews the complex literature concerning sex steroid effects on pain responses and analgesia. First, nonhuman animal research related to hormonal effects on nociceptive sensitivity and analgesic responses is presented. Next, human studies regarding gonadal hormonal influences on experimental pain responses are reviewed. Several potential mechanisms underlying hormonal effects on nociceptive processing are discussed, including hormonal effects to both peripheral and central nervous system pathways involved in pain transmission. Finally, based on these findings we draw several conclusions and make specific recommendations that will guide future research as it attempts to elucidate the magnitude and importance of sex-related hormonal effects on the experience of pain.     

Increased level of polymerase Ⅲ transcribed Alu RNA in hepatocellular carcinoma tissue

There have been extensive observations that RNA containing repetitive elements accumulates in transformed cells and tumor tissues. In the present study, we first obtained result consistent with previous observations by in situ hybridization.     

Immunohistochemical expressions of Ki-67, cyclin D1, beta-catenin, cyclooxygenase-2, and epidermal growth factor receptor in human colorectal adenoma: a validation study of tissue microarrays.

BACKGROUND: Tissue microarray (TMA) holds promise as a high-throughput method for the analysis of biomarkers in tissue specimens. The validity and reliability of this method, however, may vary for different biomarkers in different tissue specimens. OBJECTIVES: In this study, we evaluated the validity and reliability of using TMA to assess biomarkers in colorectal adenomas. METHODS: Sixty-three consecutive patients with colorectal adenomas were recruited in this study. Two TMA blocks were constructed using four punches from each adenoma (one periphery, one deep, and two middle zones). The immunostaining of five markers (Ki-67, cyclin D1, beta-catenin, cyclooxygenase-2, and epidermal growth factor receptor) was analyzed, and the concordance between data obtained from TMAs and standard whole-tissue sections was evaluated by Spearman's correlation and kappa analysis. RESULTS: Colorectal adenoma exhibited zonal, heterogeneous expression patterns for all five markers. The concordance rates for the semiquantitative evaluation of markers between data from TMAs and whole sections ranged from 87% to 93% with corresponding kappa statistics of 77% to 90%. In addition, both quantitative and semiquantitative methods were used to score TMA sections, and good correlations between these two methods were shown for all five markers with intraclass correlation coefficients ranging from 0.5 to 0.8. CONCLUSION: Our study indicates that TMA can be used to reliably assess the expression levels of Ki-67, cyclin D1, beta-catenin, cyclooxygenase-2, and epidermal growth factor receptor in colorectal adenoma tissues.     

Family history of cancer, oral contraceptive use, and ovarian cancer risk.

OBJECTIVE: The purpose of this study was to determine whether women with a family history of ovarian cancer are at reduced risk of ovarian cancer from the use of oral contraceptives and to compare their risk with that of women with no family history of ovarian cancer. STUDY DESIGN: A population-based case-controlled study was conducted from May 1994 through July 1998 in which 767 women aged 20 to 69 years with a diagnosis of epithelial ovarian cancer were ascertained from 39 hospitals in 3 northeastern states. Personal interviews with the women and 1367 control subjects provided data that allowed us to estimate the relative risk of ovarian cancer in relation to a family history of cancer and total duration of oral contraception. RESULTS: Among the 33 case patients and 24 control subjects with a first-degree family history of ovarian cancer, risk of ovarian cancer declined with increasing duration of oral contraception (P =.01). Risk reduction from short-term use of oral contraceptives (< or = 48 months) did not differ significantly by family history (combined estimate of odds ratio, 0.72; 90% CI, 0.59%-0.87%). Risk reduction from long-term use of oral contraceptives (>48 months) was greater in women with a positive family history of ovarian cancer (odds ratio, 0.12) than in women with a negative family history of ovarian cancer (odds ratio, 0.51; test of interaction, P =.04; 692 case patients, 1279 control subjects). CONCLUSION: Four to 8 years of oral contraception may substantially reduce the risk of ovarian cancer by age 70 years in women with a family history of the disease, from approximately 4 women per 100 women who did not use oral contraceptives to only 2 women per 100 women who did use oral contraceptives.