[Safety and efficacy of the early administration of levosimendan in patients with acute non-ST-segment elevation myocardial infarction and elevated NT-proBNP levels: An Early Management Strategy of Acute Heart Failure (EMS-AHF)].

Objectives: To investigated the safety and efficacy of treating patients with acute non-ST-segment elevation myocardial infarction (NSTEMI) and elevated levels of N-terminal pro-hormone B-type natriuretic peptide (NT-proBNP) with levosimendan within 24 hours of first medical contact (FMC). Methods: This multicenter, open-label, block-randomized controlled trial (NCT03189901) investigated the safety and efficacy of levosimendan as an early management strategy of acute heart failure (EMS-AHF) for patients with NSTEMI and high NT-proBNP levels. This study included 255 patients with NSTEMI and elevated NT-proBNP levels, including 142 males and 113 females with a median age of 65 (58-70) years, and were admitted in the emergency or outpatient departments at 14 medical centers in China between October 2017 and October 2021. The patients were randomly divided into a levosimendan group (n=129) and a control group (n=126). The primary outcome measure was NT-proBNP levels on day 3 of treatment and changes in the NT-proBNP levels from baseline on day 5 after randomization. The secondary outcome measures included the proportion of patients with more than 30% reduction in NT-proBNP levels from baseline, major adverse cardiovascular events (MACE) during hospitalization and at 6 months after hospitalization, safety during the treatment, and health economics indices. The measurement data parameters between groups were compared using the t-test or the non-parametric test. The count data parameters were compared between groups using the χ² test. Results: On day 3, the NT-proBNP levels in the levosimendan group were lower than the control group but were statistically insignificant [866 (455, 1 960) vs. 1 118 (459, 2 417) ng/L, Z=-1.25,P=0.21]. However, on day 5, changes in the NT-proBNP levels from baseline in the levosimendan group were significantly higher than the control group [67.6% (33.8%,82.5%)vs.54.8% (7.3%,77.9%), Z=-2.14, P=0.03]. There were no significant differences in the proportion of patients with more than 30% reduction in the NT-proBNP levels on day 5 between the levosimendan and the control groups [77.5% (100/129) vs. 69.0% (87/126), χ²=2.34, P=0.13]. Furthermore, incidences of MACE did not show any significant differences between the two groups during hospitalization [4.7% (6/129) vs. 7.1% (9/126), χ²=0.72, P=0.40] and at 6 months [14.7% (19/129) vs. 12.7% (16/126), χ²=0.22, P=0.64]. Four cardiac deaths were reported in the control group during hospitalization [0 (0/129) vs. 3.2% (4/126), P=0.06]. However, 6-month survival rates were comparable between the two groups (log-rank test, P=0.18). Moreover, adverse events or serious adverse events such as shock, ventricular fibrillation, and ventricular tachycardia were not reported in both the groups during levosimendan treatment (days 0-1). The total cost of hospitalization [34 591.00(15 527.46,59 324.80) vs. 37 144.65(16 066.90,63 919.00)yuan, Z=-0.26, P=0.80] and the total length of hospitalization [9 (8, 12) vs. 10 (7, 13) days, Z=0.72, P=0.72] were lower for patients in the levosimendan group compared to those in the control group, but did not show statistically significant differences. Conclusions: Early administration of levosimendan reduced NT-proBNP levels in NSTEMI patients with elevated NT-proBNP and did not increase the total cost and length of hospitalization, but did not significantly improve MACE during hospitalization or at 6 months.

Predictive value of cell cycle arrest biomarkers for cardiac surgery-associated acute kidney injury: a meta-analysis.

BACKGROUND: A biomarker test based on a combination of urine tissue inhibitor of metalloproteinases 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) has been used as a potential biomarker of acute kidney injury (AKI). This meta-analysis aimed to evaluate the predictive value of this biomarker for cardiac surgery-associated acute kidney injury (CSA-AKI). METHODS: We searched MEDLINE, PubMed, Cochrane, and EMBASE for studies. We evaluated the methodological quality of each included study using the Quality Assessment of Diagnostic Accuracy Studies 2 criteria. Meta-DiSc and STATA were used for statistical analyses. RESULTS: A total of 10 studies (747 patients) were included in this meta-analysis. Pooled sensitivity and specificity with corresponding 95% confidence intervals (CI) were 0.77 (95% CI: 0.70-0.83, I2=40.7%) and 0.76 (95% CI: 0.72-0.79, I2=69.1%), respectively. Pooled positive likelihood ratio (LR), negative LR, and diagnostic odds ratio were 3.26 (95% CI: 2.51-4.23, I2=50.7%), 0.32 (95% CI: 0.24-0.41, I2=6.7%), and 10.08 (95% CI: 6.85-14.84, I2=6.7%), respectively. The area under the curve estimated by summary receiver operating characteristics was 0.83 [standard error (SE) 0.023] with a Q* value of 0.759 (se 0.021). There was no heterogeneity amongst the 10 studies from both threshold and non-threshold effects. Subgroup analysis showed that the diagnostic value was related to the severity of AKI and time measurement. CONCLUSIONS: Urinary [TIMP-2]·[IGFBP7] is an effective predictive test for cardiac surgery associated acute kidney injury with good diagnostic accuracy within 24 h. Studies examining use of biomarker-guided care bundles are indicated.

Linking lignocellulosic dietary patterns with gut microbial Enterotypes of Tsaitermes ampliceps and comparison with Mironasutitermes shangchengensis.

Tsaitermes ampliceps (lower termites) and Mironasutitermes shangchengensis (higher termites) are highly eusocial insects that thrive on recalcitrant lignocellulosic diets through nutritional symbioses with gut dwelling prokaryotes and eukaryotes. We used denaturing gradient gel electrophoresis and a 16S rRNA clone library to investigate i) how microbial communities adapt to lignocellulosic diets with different cellulose and lignin content, ii) the differences in the dominant gut microbial communities of the 2 types of termites. The results indicated that gut microbiota composition in T. ampliceps was profoundly affected by 2-week diet shifts. Comparison of these changes indicated that Bacteroidetes and Spirochaetes act in cellulose degradation, while Firmicutes were responsible for lignin degradation. Additionally, Proteobacteria consistently participated in energy production and balanced the gut environment. Bacteroidetes may function without hindgut protozoans in higher termites. The diversity of enteric microorganisms in M. shangchengensis was higher than that in T. ampliceps, possibly because of the more complicated survival mechanisms of higher termites.

Cellulolytic activity and structure of symbiotic bacteria in locust guts.

Locusts are able to digest the cellulose of Gramineae plants, resulting in their being considered as major crop pests. To illustrate the mechanism involved in cellulose digestion, the cellulolytic activity and zymography in the gut contents of 16 locust species were determined using carboxymethyl cellulose (CMC) as substrate. The diversity of gut symbiotic bacteria was studied using denaturing gradient gel electrophoresis (DGGE). The results showed that high CMC activity was present in Acrididae gut fluid (mean 356.4 U/g proteins). Of the 5 locust species, Oxya chinensis had the highest diversity of intestinal symbiotic bacteria, characterized by the DGGE profile containing more than 20 bands of 16S rRNA. Klebsiella pneumoniae, in the gut of Locusta migratoria manilensis, was identified as the most abundant symbiotic bacterium by DNA sequencing, with a relative abundance of 19.74%. In comparison, Methylobacterium sp was the most dominant species in the Atractomorpha sinensis gut, with a relative abundance of 29.04%. The results indicated that the cellulolytic enzymes and gut microbial communities probably reflected their phylogenetic relationship with different locust species and associated feeding strategies.

Evaluation of cellulolytic activity in insect digestive fluids.

Efficient and low-cost cellulolytic enzymes are urgently needed to degrade recalcitrant plant biomass during the industrial production of lignocellulosic biofuels. Here, the cellulolytic activities in the gut fluids of 54 insect species that belong to 7 different taxonomic orders were determined using 2 different substrates, carboxymethyl cellulose (CMC) (approximating endo-ß-1,4-glucanase) and filter paper (FP) (total cellulolytic activities). The use of CMC as the substrate in the zymogram analysis resulted in the detection of distinct cellulolytic protein bands. The cellulolytic activities in the digestive system of all the collected samples were detected using cellulolytic activity analysis. The highest CMC gut fluid activities were found in Coleoptera and Orthoptera, while FP analysis indicated that higher gut fluid activities were found in several species of Coleoptera and Lepidoptera. In most cases, gut fluid activities were higher with CMC than with FP substrate, except for individual Lepidoptera species. Our data indicate that the origin of cellulolytic enzymes probably reflects the phylogenetic relationship and feeding strategies of different insects.

Expression of activin A and follistatin in glioblastoma and their effects on U87 in vitro.

In some cancer cell lines, the gene encoding activin A (inhibin ßA [INHBA]) is over-expressed and enhances cancer proliferation. Protein levels of activin A and follistatin were assessed in glioblastoma and normal brain tissues in this study, and the effect of activin A and follistatin treatment on the proliferation of U87 human glioblastoma cells in vitro was also studied. High levels of activin A were observed in glioblastomas compared with normal brain tissue. In contrast, follistatin levels were similar between the two tissues. [(3)H]Thymidine assay showed that activin A (3 - 30 ng/ml) produced a dose-dependent increase in DNA synthesis of U87 cells compared with controls. Flow cytometric analyses showed that activin A increased the proliferative index of U87 cells compared with controls. Activin A also induced up-regulation of p-SMAD2/3 in a dose-dependent manner. Treatment of U87 cells with follistatin blocked these activin A-induced effects. The disequilibrium between activin A and follistatin may play a role in the development of glioblastoma.

Upregulation of long noncoding RNA MRCCAT1 predicts poor prognosis and functions as an oncogene in glioma.

OBJECTIVE: This study aimed to investigate the expressions, clinical significances, roles, and mechanism of action of MRCCAT1 in glioma. PATIENTS AND METHODS: The expression of MRCCAT1 in 103 glioma tissues with different grades and 21 normal brain tissues was measured by qPCR. The prognostic value of MRCCAT1 was investigated by Kaplan-Meier survival analysis. The biological roles of MRCCAT1 on glioma cell proliferation were assessed by Glo cell viability assays and ethynyl deoxyuridine incorporation assays. The roles of MRCCAT1 on glioma cell migration were evaluated by transwell assays. The effects of MRCCAT1 on p38-MAPK signaling were assessed by Western blot. RESULTS: MRCCAT1 is upregulated in glioma tissues and positively associated with glioma grades. Increased expression of MRCCAT1 confers poor prognosis of glioma patients independent of glioma grades. Ectopic expression of MRCCAT1 promotes glioma cell proliferation and migration. Knockdown of MRCCAT1 inhibits glioma cell proliferation and migration. Mechanistically, we found that MRCCAT1 activates p38-MAPK signaling in glioma. CONCLUSIONS: MRCCAT1 is upregulated in glioma. Increased expression of MRCCAT1 predicts poor outcome of glioma patients. MRCCAT1 promotes glioma cell proliferation and migration via activating p38-MAPK signaling. MRCCAT1 may be a potential prognostic biomarker and therapeutic target for glioma.

Saturated fat intake and prostate cancer aggressiveness: results from the population-based North Carolina-Louisiana Prostate Cancer Project.

BACKGROUND: Epidemiologic and laboratory evidence supports a role for cholesterol in prostate cancer (PC). Dietary saturated fat content impacts serum cholesterol levels. However, epidemiologic associations between saturated fat and PC aggressiveness are inconsistent. We hypothesized that high saturated fat intake would be associated with increased PC aggressiveness, and that statin use would modify this association. METHODS: Of 1854 PC cases in the North Carolina-Louisiana PC Project, 321 (17%) were classified as high aggressive (Gleason sum ⩾8, PSA>20 ng ml-1, or Gleason sum ⩾7 and clinical stage T3-4) or low/intermediate aggressive (all other cases). Using low/intermediate aggressive cases as the referent group, we examined the association between tertiles of total fat-adjusted saturated fat intake and high aggressive PC using logistic regression, overall and stratified by race and statin use. We examined total fat-adjusted polyunsaturated and monounsaturated fatty acids (PUFA and MUFA, respectively), trans fat and cholesterol intake in secondary analysis. RESULTS: High total fat-adjusted saturated fat intake was associated with an elevated odds ratio (OR) for aggressive PC (ORT3vsT1 1.51; 95% CI 1.10-2.06; P-trend=0.009), with an attenuated association in statin users (ORT3vsT1 1.16; 95% CI 0.67-2.01; P-trend=0.661) compared with non-users (ORT3vsT1 1.71; 95% CI 1.16-2.51; P-trend=0.053). High total fat-adjusted cholesterol intake was associated with aggressive PC in European Americans (ORT3vsT1 1.62; 95% CI 1.02-2.58; P-trend=0.056), but not African Americans (ORT3vsT1 0.92; 95% CI 0.60-1.42; P-trend=0.750). High total fat-adjusted PUFA was inversely associated with PC aggressiveness (ORT3vsT1 0.75; 95% CI 0.55-1.03), although this was not significant. No associations were found between total fat-adjusted MUFA or trans fat and PC aggressiveness. CONCLUSIONS: High total fat-adjusted saturated fat intake was associated with increased PC aggressiveness, with a suggestion of a stronger effect in men not using statins. The association between total fat-adjusted cholesterol intake and PC aggressiveness was most pronounced in European Americans.

Macrophage colony-stimulating factor complementary DNA: a candidate for gene therapy in metastatic melanoma.

BACKGROUND: At present, there is no highly effective treatment for metastatic melanoma. Innovative approaches aimed at inducing a more effective immune response against tumors have shown promising results in animal models. One approach involves the genetic modification of tumor cells so that they produce cytokines that stimulate an immune response. PURPOSE: The aim of this study was to determine the effectiveness of cytokine gene therapy for metastatic melanoma in a murine melanoma model. METHODS: B16F10 murine melanoma cells, which readily metastasize to the lungs, were transduced with a retroviral vector containing genes encoding neomycin resistance and human macrophage colony-stimulating factor (M-CSF). The presence of M-CSF messenger RNA in transduced cells was examined by coupled reverse transcription and polymerase chain reaction. Concentrations of soluble M-CSF in cell culture supernatants were determined by enzyme-linked immunosorbent assays (ELISAs). A clonal cell line, designated N+/CSF+, that expressed and secreted M-CSF was identified. Another clonal cell line, designated N+/CSF-, did not secrete M-CSF at levels detectable by ELISA. B16F10, N+/CSF-, and N+/CSF+ cells, individually or in combination, were injected intravenously or subcutaneously into C57BL/6 mice; we then evaluated the tumorigenicity and metastatic behavior of the cells, as well as the immune responses and survival of the mice. The immune responses assayed were the cytotoxic T lymphocyte (CTL) and peritoneal exudate cell (PEC) tumoricidal activities. RESULTS: Injection of B16F10 cells into the tail vein of C57BL/6 mice led to the establishment of lung metastases by week 2 and death by week 8. Injection of the N+/CSF+ or N+/CSF- cells led to the establishment of lung metastases that were detected at 2 and 3 weeks, respectively; however, these metastatic lesions were eliminated, and the animals had survival rates similar to those of the noninjected control mice. Injection of mice with a mixture of B16F10 and N+/CSF- cells resulted in the development of metastatic disease and 0% survival at 8 weeks, whereas mice that had been given an injection of a mixture of B16F10 and N+/CSF+ cells had an 80% survival rate at 8 weeks and survived at least two times longer (P = .007). The CTL and PEC tumoricidal activities in animals given an injection of N+/CSF+ cells suggested that monocytes and lymphocytes were responsible for the observed antitumor response. CONCLUSION: These findings suggest that the expression of M-CSF by genetically modified melanoma cells caused an effective antitumor immune response in host C57BL/6 mice and, thus, prolonged survival over that observed in the control mice.

Guiding ribozyme cleavage through motif recognition: the mechanism of cleavage site selection by a group ii intron ribozyme.

The mechanism by which group II introns cleave the correct phosphodiester linkage was investigated by studying the reaction of mutant substrates with a ribozyme derived from intron ai5gamma. While fidelity was found to be quite high in most cases, a single mutation on the substrate (+1C) resulted in a dramatic loss of fidelity. When this mutation was combined with a second mutation that induces a bulge in the exon binding site 1/intron binding site 1 (EBS1/IBS1) duplex, the base-pairing register of the EBS1/IBS1 duplex was shifted and the cleavage site moved to a downstream position on the substrate. Conversely, when mismatches were incorporated at the EBS1/IBS1 terminus, the duplex was effectively truncated and cleavage occurred at an upstream site. Taken together, these data demonstrate that the cleavage site of a group II intron ribozyme can be tuned at will by manipulating the thermodynamic stability and structure of the EBS1/IBS1 pairing. The results are consistent with a model in which the cleavage site is not designated through recognition of specific nucleotides (such as the 5'-terminal residue of EBS1). Instead, the ribozyme detects a structure at the junction between single and double-stranded residues on the bound substrate. This finding explains the puzzling lack of phylogenetic conservation in ribozyme and substrate sequences near group II intron target sites.

Characterization of an autoantigen associated with chronic ulcerative stomatitis: the CUSP autoantigen is a member of the p53 family.

A unique clinical syndrome has been described in which patients have chronic oral ulceration and autoantibodies to nuclei of stratified squamous epithelium. We have characterized the autoantibodies from patients sera and found that the major autoantigen is a 70 kDa epithelial nuclear protein. Sequencing of the cDNA for this protein, chronic ulcerative stomatitis protein, revealed it to be homologous to the p53 tumor suppressor and to the p73 putative tumor suppressor, and to be a splicing variant of the KET gene. The p53-like genes, p73 and the several KET splicing variants, are recently described genes of uncertain biologic and pathologic significance. This study provides the first clear association of a p53-like protein with a disease process.

Nutritional status of folate and colon cancer risk: evidence from NHANES I epidemiologic follow-up study.

PURPOSE: This manuscript utilized the NHANES I Epidemiologic Follow-up Study (NHEFS), a national probability sample of the U.S. non-institutionalized population, to examine whether the intake of folate at baseline is associated with colon cancer risk. METHODS: The NHEFS consists of 14,407 subjects with 20 years of follow-up. Sociodemographic status, dietary information, family history of colon cancer, alcohol and aspirin use, smoking status, and body mass index (BMI) are included in the Cox proportional hazard model to examine confounding effects. RESULTS: After adjusting for confounders, a marginally significant association was observed between folate intake and reduced colon cancer risk. Gender and alcohol consumption appears to have an interactive effect with this association. The stratified results suggest that dietary folate is significantly inversely associated with colon cancer in men (relative risk (RR) = 0.40, 95% confidence interval (CI) = 0.18, 0.88) who consumed more than 249 microg/day of folate and that there is a significant dose-response relationship (p = 0.03). The association did not reach statistical significance in women. Using a composite dietary profile, we found that there is a significantly increased risk for men who consumed low-folate, low-methionine, and high alcohol diets when compared to male non-drinkers who consumed high-folate and high methionine diets (RR = 2.67, 95% CI = 1.16, 6.16). CONCLUSIONS: This study found significant association between folate intake and reduced colon cancer risk among men and non-drinkers, but not women or drinkers. The study supports a synergistic interaction between intakes of folate, methionine and alcohol and colon cancer risk.

CUSP/p63 expression in rat and human tissues.

The human homolog of KET, p63, bears strong homology to the tumor suppressor p53 and plays an essential role in epithelial development. CUSP, the most abundant cutaneous product of p63, has been identified as an autoantigen in chronic ulcerative stomatitis (CUS). The original report of KET expression at least partially contradicts p63 expression subsequently reported by many different groups. We have examined p63 expression by Northern analysis of RNA from multiple human tissues and by indirect immunofluorescence of rat tissue with CUS patient sera. Northern analysis reveals p63 RNA in skin, thymus, placenta, skeletal muscle, kidney, and lung, with non-transactivating p63 RNA in skin, thymus, and placenta. Reverse transcriptase polymerase chain reaction (rtPCR) assays show abundant non-transactivating p63 RNA, and little to no transactivating p63 RNA, in human basal cell carcinoma as well as in normal skin adjacent to the tumors. p63 RNA expression was not detected in brain, heart, colon, spleen, liver, or small intestine. Immunofluorescence reveals p63 expression in skin, oral epithelium, tongue, kidney, and trachea, but not in liver, large intestine, testis, skeletal muscle, or heart. Focal p63 expression within tissues, the complex array of isoforms encoded by the gene, and the specificity of the probes and antibodies utilized, may all contribute to contradictory accounts of CUSP/p63 expression.

Effect of parental mental health status on adolescents' dietary behaviors.

PURPOSE: The purpose of this study was to explore whether adolescents of substance-abusing and depressed parents were more likely to have poor dietary behaviors than those in the health comparison families. METHODS: The sample consisted of 841 adolescents in families of substance-abusing parents, depressed parents, and parents without a diagnosable psychiatric disorder. All adolescents were given a food frequency questionnaire. RESULTS: Adolescents whose parents had substance abuse disorder had lower intakes of fruits and higher intakes of high fat foods, and also ate more frequently at fast-food restaurants and purchased more snacks. Adolescents whose parents were depressed had lower intakes of all food groups. Mother's mental health status impacted more on adolescents' dietary behaviors than did the father's mental health status. CONCLUSION: This research suggests that at-risk behaviors among youth of psychiatrically impaired parents may extend to food behaviors.

Antiangiogenic therapy with somatostatin receptor-mediated in situ radiation.

Tumor growth and the development of metastases require an angiogenic response. Angiogenic vessels uniquely express somatostatin subtype 2 (sst 2) receptors that can transport somatostatin or its analogs into the cell. We hypothesized that radiolabeled somatostatin analogs could inhibit the angiogenic response by selectively destroying proliferating endothelial cells. We evaluated the antiangiogenic effects of 111In-pentetreotide, an sst 2-preferring somatostatin analog in a human vessel model. Disks of human placental vein were embedded in fibrin gels in culture and observed for angiogenic sprouting for 14 days. Vein disks were treated with 111In-pentetreotide (1.5, 15, and 150 microCi/mL) on the day of implantation. Control groups included disks treated with nutrient medium alone, with 111In-chloride, and with unlabeled pentetreotide. The percentage of wells that initiated an angiogenic response and the overall length and density of neovessel sprouts were assessed on Day 14. 111In-pentetreotide treatment did not completely block initiation of the angiogenic response but significantly decreased the growth of neovessels after initiation. Both the receptor-specific Auger electron-induced and nonspecific gamma radiation-mediated effects contributed to the angiotoxicity.

Functionalized gold nanorods for thermal ablation treatment of bladder cancer.

Nanomaterial-directed, photothermal ablation is a practical future approach for the treatment of early-stage bladder cancer. Using a new PEGylation technique with bi-functional nitrophenyl carbonate PEG (bi-NPC-PEG) that promotes uniform suspension of the nanomaterial in solution, we have shown that gold nanorods conjugated to an anti-EGFR antibody (nano-alphaEGFR) bind effectively to EGFR-expressing bladder cancer cells. The subsequent application of infrared light, specifically tuned to the plasmon resonance of the nanorods used in this work, allows for the specific heating of nano-alphaEGFR to the point of localized cellular death. Such an approach, administering nano-alphaEGFR intravesically via a urinary catheter and infrared light via a modified cystoscope, represents a novel, future clinical application of this technology, which avoids the problem of systemic exposure and clearance of nanoparticles from body.

Sequence of cDNA for rat cystathionine gamma-lyase and comparison of deduced amino acid sequence with related Escherichia coli enzymes.

A cDNA clone for cystathionine gamma-lyase was isolated from a rat cDNA library in lambda gt11 by screening with a monospecific antiserum. The identity of this clone, containing 600 bp proximal to the 3'-end of the gene, was confirmed by positive hybridization selection. Northern-blot hybridization showed the expected higher abundance of the corresponding mRNA in liver than in brain. Two further cDNA clones from a plasmid pcD library were isolated by colony hybridization with the first clone and were found to contain inserts of 1600 and 1850 bp. One of these was confirmed as encoding cystathionine gamma-lyase by hybridization with two independent pools of oligodeoxynucleotides corresponding to partial amino acid sequence information for cystathionine gamma-lyase. The other clone (estimated to represent all but 8% of the 5'-end of the mRNA) was sequenced and its deduced amino acid sequence showed similarity to those of the Escherichia coli enzymes cystathionine beta-lyase and cystathionine gamma-synthase throughout its length, especially to that of the latter.

Visualizing the solvent-inaccessible core of a group II intron ribozyme.

Group II introns are well recognized for their remarkable catalytic capabilities, but little is known about their three-dimensional structures. In order to obtain a global view of an active enzyme, hydroxyl radical cleavage was used to define the solvent accessibility along the backbone of a ribozyme derived from group II intron ai5gamma. These studies show that a highly homogeneous ribozyme population folds into a catalytically compact structure with an extensively internalized catalytic core. In parallel, a model of the intron core was built based on known tertiary contacts. Although constructed independently of the footprinting data, the model implicates the same elements for involvement in the catalytic core of the intron.

Involvement of Gas7 in nerve growth factor-independent and dependent cell processes in PC12 cells.

Gas7, a growth arrest-specific gene originally isolated from serum-starved mouse fibroblast cells, is expressed in vivo predominantly in the brain and is required for neurite formation in cultured mouse cerebellar neurons (Ju et al. [1998] Proc. Natl. Acad. Sci. USA 95: 11423-11428). Here we report that Gas7 plays a key role in the morphological differentiation of PC12 preneuronal rat pheochromocytoma cells (PC12 cells). We found that overexpression of murine Gas7 in PC12 cells leads to an expanded cell morphology and promotes spike-like cell processes that resemble the early stages of neurite formation. These processes undergo elongation upon addition of nerve growth factor (NGF). We also found that the addition of NGF induces the production of endogenous rat-Gas7 (rGas7), which is transiently elevated prior to the appearance of NGF-promoted neurite outgrowths. Furthermore, inhibition of endogenous rGas7 production by antisense nucleotides complimentary to the translation initiation region of a rGas7 cDNA (AJ131902) reduces the NGF-promoted neurite outgrowths. Our results demonstrate that Gas7 by itself influences early cell morphological development and likely functions as an early-stage intermediary in NGF-induced neuronal differentiation of PC12 culture cells.