[The mechanism of antiarrhythmic action of the endogenous ORL1 receptor agonist nociceptin]

Prophylactic intravenous (i.v.) injections of a selective agonist of ORL1 receptors nociceptin (orphanin FQ) in a dose of 0.4 mg/kg prevented the development of aconitine-induced arrhythmia in rats narcotized with diethyl ether or chloralose. Pretreatment with L-NAME (50 mg/kg) completely abolished this effect of orphanin FQ, while the pretreatment with indomethacin (10 mg/kg) only attenuated the agonist effect, rather than abolished it completely. At the same time, pretreatment with hexamethonium (10 mg/kg) or glibenclamide (3 mg/kg) had no effect on the nociceptin-dependent cardiac tolerance to the arrhythmogenic action of aconitine. Intracerebroventricular (i.c.v.) infusion of orphanin FQ (36 microg) also prevented the onset of aconitine-induced arrhythmia, but this effect was completely abolished by hexamethonium. It is concluded that the antiarrhythmic action of nociceptin with respect to aconitine-induced arrhythmia upon i.v. and i.c.v. administration is explained by different mechanisms. In the former case, the effect of orphanin FQ is related to the activation of NO synthase and cyclooxygenase, while the central action involves the vegetative nervous system.

CYP1A1, cigarette smoking, and colon and rectal cancer

Cytochrome P-450 (CYP) is involved in the activation and metabolism of polycyclic aromatic hydrocarbons in tobacco products. The authors evaluated the association of two polymorphisms in the CYP1A1 gene--the noncoding Msp I polymorphism in the 3'-untranslated region and the Ile462Val polymorphism in exon 7--with colon and rectal cancer. The authors used data from two incident case-control studies of colon cancer (1,026 cases and 1,185 controls) and rectal cancer (820 cases and 1,036 controls) conducted in California and Utah (1991-2002). CYP1A1 genotype was not associated with colon or rectal cancer. Having GSTM1 present, a CYP1A1 variant allele, and the rapid-acetylator NAT2 imputed phenotype was associated with increased risk of colon cancer (odds ratio = 1.7, 95% confidence interval: 1.2, 2.3). Among men, the greatest colon cancer risk was observed for having any CYP1A1 variant allele and currently smoking (odds ratio = 2.5, 95% confidence interval: 1.3, 4.8; Wald chi(2)test: p < 0.01). Assessment of GSTM1 and CYP1A1 and rectal cancer in men showed a twofold elevation in risk for more than 20 pack-years of smoking, except among those with GSTM1 present who had a variant CYP1A1 allele. These data support the association between smoking and colon and rectal cancer. Smoking may have a greater impact on colorectal cancer risk based on CYP1A1 genotype; this might further be modified by GSTM1 for rectal cancer risk.

Family history and colorectal cancer: predictors of risk

INTRODUCTION

While the association between family history of colorectal cancer in first-degree relatives and risk of developing colon cancer has been well defined, the association with rectal cancer is much less clear. The purpose of this study is to define rectal cancer risk associated with family history of colorectal cancer in first-degree relatives. We also evaluate diet and lifestyle factors associated with developing colorectal cancer among participants with a positive family history.

METHODS

Data were available from two population-based case--control studies of colon and rectal cancer. Participants were members of the Kaiser Permanente Medical Care Program (KPMCP) or residents of the state of Utah. Cases were first primary colon cancer diagnosed between 1991 and 1994 (n = 1308 cases and 1544 controls) or rectal cancer diagnosed between 1997 and 2001 (n = 952 cases and 1205 controls).

RESULTS

A family history of colorectal cancer in any first-degree relatives slightly increased risk of rectal cancer (OR: 1.37 95% CI: 1.02-1.85). Family history of colorectal cancer was associated with the greatest risk among those diagnosed at age 50 or younger (OR: 2.09 95% CI: 0.94-4.65 for rectal tumors; OR: 3.00 95% CI: 0.98-9.20 for distal colon tumors; and OR: 7.88 95% CI: 2.62-23.7 for proximal colon tumors). Factors significantly associated with cancer risk among those with a family history of colorectal cancer, included not having a sigmoidoscopy (OR: 2.81 95% CI: 1.86-4.24): a diet not Prudent, i.e. high in fruits, vegetables, whole grains, fish and poultry, (OR: 2.79 95% CI: 1.40-5.56); smoking cigarettes (OR: 1.68 95% CI: 1.12-2.53), and eating a Western diet, i.e. a diet high in meat, refined grains, high-fat foods, and fast foods, (OR: 2.15 95% CI: 1.06-4.35). Physical inactivity was not associated with increased cancer risk among those with a positive family history of colorectal cancer.

SUMMARY

These results confirm observations reported by others that a family history of colorectal cancer increases risk of cancer among those diagnosed at a younger age. Associations with family history are weakest for rectal cancer and strongest for proximal colonic tumors. Since several diet and lifestyle factors influence development of cancer among those with a family history of the disease, there appears to be practical approaches for individuals with a family history of colorectal cancer to reduce their cancer risk.

Family history and colorectal cancer: predictors of risk

INTRODUCTION

While the association between family history of colorectal cancer in first-degree relatives and risk of developing colon cancer has been well defined, the association with rectal cancer is much less clear. The purpose of this study is to define rectal cancer risk associated with family history of colorectal cancer in first-degree relatives. We also evaluate diet and lifestyle factors associated with developing colorectal cancer among participants with a positive family history.

METHODS

Data were available from two population-based case--control studies of colon and rectal cancer. Participants were members of the Kaiser Permanente Medical Care Program (KPMCP) or residents of the state of Utah. Cases were first primary colon cancer diagnosed between 1991 and 1994 (n = 1308 cases and 1544 controls) or rectal cancer diagnosed between 1997 and 2001 (n = 952 cases and 1205 controls).

RESULTS

A family history of colorectal cancer in any first-degree relatives slightly increased risk of rectal cancer (OR: 1.37 95% CI: 1.02-1.85). Family history of colorectal cancer was associated with the greatest risk among those diagnosed at age 50 or younger (OR: 2.09 95% CI: 0.94-4.65 for rectal tumors; OR: 3.00 95% CI: 0.98-9.20 for distal colon tumors; and OR: 7.88 95% CI: 2.62-23.7 for proximal colon tumors). Factors significantly associated with cancer risk among those with a family history of colorectal cancer, included not having a sigmoidoscopy (OR: 2.81 95% CI: 1.86-4.24): a diet not Prudent, i.e. high in fruits, vegetables, whole grains, fish and poultry, (OR: 2.79 95% CI: 1.40-5.56); smoking cigarettes (OR: 1.68 95% CI: 1.12-2.53), and eating a Western diet, i.e. a diet high in meat, refined grains, high-fat foods, and fast foods, (OR: 2.15 95% CI: 1.06-4.35). Physical inactivity was not associated with increased cancer risk among those with a positive family history of colorectal cancer.

SUMMARY

These results confirm observations reported by others that a family history of colorectal cancer increases risk of cancer among those diagnosed at a younger age. Associations with family history are weakest for rectal cancer and strongest for proximal colonic tumors. Since several diet and lifestyle factors influence development of cancer among those with a family history of the disease, there appears to be practical approaches for individuals with a family history of colorectal cancer to reduce their cancer risk.

Physical activity and colorectal cancer

Physical activity has been inconsistently associated with rectal cancer despite the consistent association between physical activity and colon cancer. In this study, the authors evaluated the association between physical activity and rectal cancer using the same questionnaire used to evaluate the previously reported association with colon cancer. A population-based study of 952 incident cases of cancer in the rectum and rectosigmoid junction and 1,205 age- and sex-matched controls was conducted in Utah and northern California at the Kaiser Permanente Medical Care Program between 1997 and 2002. Vigorous physical activity was associated with reduced risk of rectal cancer in both men and women (odds ratio (OR) = 0.60, 95% confidence interval (CI): 0.44, 0.81 for men; OR = 0.59, 95% CI: 0.40, 0.86 for women). Among men, moderate levels of physical activity also were associated with reduced risk of rectal cancer (OR = 0.70, 95% CI: 0.51, 0.97). Participation in vigorous activity over the past 20 years conferred the greatest protection for both men and women (OR = 0.55, 95% CI: 0.39, 0.78 for men; OR = 0.44, 95% CI: 0.30, 0.67 for women). In summary, physical activity was associated with reduced risk of rectal cancer in these data. The reduced risk was similar to that previously observed for colon cancer.

GSTM-1 and NAT2 and genetic alterations in colon tumors

OBJECTIVE

Phase II metabolizing enzymes such as glutathione S-transferases and N-acetyltransferase are involved in the detoxification of carcinogens. Genetic variants of genes coding for these enzymes have been evaluated as to their association with colon cancer, both as independent risk factors and as effect modifiers for associations with diet and cigarette smoking. In this study, we evaluate associations between the GSTM-1 genotype and the NAT2-imputed phenotype and acquired mutations in tumors.

METHODS

Data is taken from a set of 1836 cases and 1958 controls with colon cancer who were part of a large case-control study of colon cancer and whose tumors were previously analyzed for Ki-ras, p53, and microsatellite instability (MSI). We also evaluate the modifying effects of these genetic variants with diet and cigarette smoking, factors previously identified as being associated with specific tumor alterations.

RESULTS

Neither GSTM-1 nor the NAT2-imputed phenotype was independently associated with Ki-ras, p53, or MSI. Cigarette smoking significantly increased the risk of tumors involving the MSI pathway. Additionally, cigarette smoking doubled the risk of p53 transversion mutations among those who were GSTM-1 present. Cases were slightly more likely to have a p53 mutation if they frequently consumed red meat and had the imputed NAT2 intermediate/rapid phenotype relative to slow phenotype/infrequent consumers of red meat (OR 2.0, 95% CI 1.3-3.0 for intermediate/rapid).

CONCLUSIONS

These data provide support that diet and cigarette smoking may be associated with specific disease pathways, although GSTM-1 and NAT2 do not independently appear to alter susceptibility to these diet and lifestyle factors.

Diet activity, and lifestyle associations with p53 mutations in colon tumors

Inactivation of the p53 tumor suppressor gene is a common event in the development of colon cancer. We use data collected as part of a multicenter case-control study of colon cancer to evaluate associations between p53 mutations and diet and lifestyle factors. p53 mutational status was determined for 1458 incident cases of colon cancer using single-strand conformational polymorphism/sequencing of exons 5-8. We determined associations among those with and without mutations compared with population-based controls (N = 2410) and to cases with p53 mutations compared with cases without p53 mutations. Associations also were examined by location and function of specific types of p53 mutations. p53 mutations were identified in tumors in 47.1% of cases; 81.9% of people with mutations had a missense mutation. Cases with a p53 mutation were more likely to consume a Western-style diet, compared with controls [odds ratio (OR), 2.03; 95% confidence interval (CI), 1.53-2.69], than were cases who were p53 wild type (Wt), compared with controls (OR, 1.57;95% CI, 1.20-2.06). Specific components of the Western-style diet, including diets with a high glycemic load (mutation versus control: OR, 1.48; 95% CI, 1.11-1.98 and Wt versus control: OR, 0.98; 95% CI, 0.75-1.28) and diets high in red meat, fast food, and trans-fatty acid (mutation versus control: OR, 1.92; 95% CI, 1.47-2.50 and Wt versus control: OR, 1.39; 95% CI, 1.08-1.80) appeared to be most strongly associated with p53 mutations. Diets with a high glycemic load (relative to lowest intake) were significantly associated with missense mutations (OR, 1.69; 95% CI, 1.23-2.33 comparing p53+ to controls and OR, 1.72; 95% CI, 1.19-2.50 comparing cases p53+ to cases p53 Wt), as were diets high in red meat, fast food, and trans-fatty acids (OR, 1.92; 95% CI, 1.14-2.56 comparing p53+ to controls and OR, 1.40; 95% CI, 1.00-1.98 comparing cases p53+ to cases p53 Wt). Physical inactivity, large body mass index, cigarette smoking, using aspirin/nonsteroidal anti-inflammatory drugs, and other dietary factors appeared to be comparably associated with colon cancer in those with and without p53 mutations. These data suggest that components of a Western-style diet such as high consumption of red meat and foods that increase glycemic load are associated with a p53 disease pathway.

Prevention and cure of complications from multiple-electrode radiofrequency treatment of liver tumors

BACKGROUND/AIMS

To determine the complication rate of multiple-electrode radiofrequency treatment of liver tumors, and their prevention and cure.

METHODS

114 patients with liver tumors were treated 170 times using multiple-electrode radiofrequency. The clinical complications and their prevention and cure were observed.

RESULTS

The complication rate was 9.6%. The complications included 1 case of colon perforation, 4 cases of skin burn, 5 cases of hydrothorax, and 1 case subcutaneous hemorrhage, but none of the patient died due to these complications.

CONCLUSION

The complication rate of multiple-electrode radiofrequency treatment of liver tumors is low and the complications could be prevented and cured.

Characterization of 5'-regulatory region of human myostatin gene: regulation by dexamethasone in vitro

We cloned and characterized a 3.3-kb fragment containing the 5'-regulatory region of the human myostatin gene. The promoter sequence contains putative muscle growth response elements for glucocorticoid, androgen, thyroid hormone, myogenic differentiation factor 1, myocyte enhancer factor 2, peroxisome proliferator-activated receptor, and nuclear factor-kappaB. To identify sites important for myostatin's gene transcription and regulation, eight deletion constructs were placed in C(2)C(12) and L6 skeletal muscle cells. Transcriptional activity of the constructs was found to be significantly higher in myotubes compared with that of myoblasts. To investigate whether glucocorticoids regulate myostatin gene expression, we incubated both cell lines with dexamethasone. On both occasions, dexamethasone dose dependently increased both the promoter's transcriptional activity and the endogenous myostatin expression. The effects of dexamethasone were blocked when the cells were coincubated with the glucocorticoid receptor antagonist RU-486. These findings suggest that glucocorticoids upregulate myostatin expression by inducing gene transcription, possibly through a glucocorticoid receptor-mediated pathway. We speculate that glucocorticoid-associated muscle atrophy might be due in part to the upregulation of myostatin expression.

Lifestyle factors and Ki-ras mutations in colon cancer tumors

Heterogeneity in colon tumors implies that environmental, lifestyle, or genetic factors influence the type of mutations seen in tumors. In this study we evaluate the association between previously identified risk factors for colon cancer and Kirsten-ras (Ki-ras) mutations in tumors. The presence of Ki-ras mutations in codons 12 and 13 were determined in a population-based case-control study of colon cancer. Participants were between 30 and 79 years of age at time of diagnosis and include both men and women. Questionnaire data were used to obtain information on lifestyle factors. Valid study data and Ki-ras mutational status were available from 1428 cases of colon cancer, data from 2410 controls were available for comparative purposes. Participants with Ki-ras mutations were more likely to have proximal rather than distal tumors. Cigarette smoking, use of aspirin and/or NSAIDs, use of vitamin/mineral supplements, and consumption of caffeine were associated with both Ki-ras+ and Ki-ras- tumors; the associations were not confounded by dietary intake or other lifestyle factors. Among men, but not among women, those with low levels of physical activity were more likely to have a tumor with a Ki-ras mutation than one without a Ki-ras mutation. However, among women, those with a larger BMI were more likely to have a Ki-ras mutation in their tumor. Given the limited information available on what causes Ki-ras mutations, the information generated from this study indicates that these factors previously associated with colon cancer work through other disease pathways.

Osteoblast responses to as-deposited and heat treated sputtered CaP surfaces

The clinical success of dental implants is governed by implant surfaces and bone cell responses that promote rapid osseointegration. The objective of this study was to evaluate the in vitro osteoblast cell response to heat treated and non-heat treated CaP coatings. In this study, the heat treated surfaces exhibited a poorly crystallized HA-type structure whereas the non-heat treated surface exhibited an amorphous structure. The heat treated CaP surfaces were observed to have a mean contact angle measurement of 57.95+/-0.95 degrees, whereas the non-heat treated CaP surfaces were observed to have a mean contact angle measurement of 44.6+/-0.3 degrees. From the in vitro cell culture study, the ATTC CRL 1486 human embryonic palatal mesenchyme (HEPM) cells displayed a similar protein production and hexosaminidase activity on the heat treated and non-heat treated CaP surfaces throughout the nine day experiment. However, the HEPM cells cultured on non-heat treated CaP surfaces were observed to have higher specific ALP activity after nine days' incubation compared to cells cultured on heat treated CaP surfaces. The higher specific ALP activity by cells on non-heat treated surfaces were suggested to be attributed to the lower degree of crystallinity and the lower contact angles observed in this study.

Nuclear export of influenza virus ribonucleoproteins: identification of an export intermediate at the nuclear periphery

A critical phase of the influenza virus life cycle is the regulated translocation of genomic ribonucleoproteins (vRNPs) from the nuclear interior, across the nuclear envelope, and into the cytoplasm. Two viral proteins, M1 and NS2, have previously been implicated as mediators of vRNP export. We show here that vRNP nuclear export is prevented by leptomycin B (LMB), an inhibitor of the cellular factor CRM1. In LMB-treated cells, vRNPs were found in a peripheral nuclear location that localized with the nuclear lamina. vRNPs were not colocalized with either M1 or NS2. In situ extraction of cells late in infection also revealed a peripheral localization of nuclear vRNPs, whereas early in infection vRNPs were dispersed throughout the nuclear interior. We believe that vRNPs at the nuclear periphery represent a novel intermediate in the influenza virus nuclear export pathway.

Polyproline II helix is a key structural motif of the elastic PEVK segment of titin

Titin is a family of giant elastic proteins that constitute an elastic sarcomere matrix in striated muscle. In the I-band region of the sarcomere, where titin extends and develops passive force upon stretch, titin is composed of tandem repeats of approximately 100 residue immunoglobin domains and approximately 28-residue PEVK modules. We have performed 2D NMR and circular dichroism (CD) studies of the conformations of one representative 28-mer PEVK module from human fetal titin (PEPPKEVVPEKKAPVAPPKKPEVPPVKV). NMR data of synthetic peptides of this module as well as three constituent peptides of 9 to 12 residues in aqueous solutions reveal distinguishing features for left-handed three-residue per turn PPII helices: the lack of NOE NN(i, i+1), very large NOE alphaN(i, i+1)/NN(i, i+1), no medium range NOE alphaN(i, i+2), and dihedral angles phi and psi values of -78 and 146, respectively. Structural determinations indicate the presence of three short stretches of PPII helices of 4, 5, and 6 residues that are interposed with an unordered, and presumably flexible, spacer region to give one "polyproline II helix-coil" or "PhC" motif for roughly every 10 residues. These peptides also display the characteristic PPII CD spectra: positive peak or negative shoulder band at 223 nm, negative CD band near 200 nm, and biphasic thermal titration curves that reflect varied stability of these PPII helices. We propose that this PhC motif is a fundamental feature and that the number, length, stability, and distribution of PPII is important in the understanding of the elasticity and protein interactions of the PEVK region of titin.

[An immunohistochemistry study on extracellular matrix of lamina cribrosa in optic nerve head of experimental glaucoma]

OBJECTIVE

To observe the change of the macromolecular components of extracellular matrix of lamina cribrosa (LC) in experimental glaucoma.

METHODS

Immunoperoxidase (ABC) staining method was used to investigate the changes of collagen type IV and laminin in the lamina cribrosa of 9 monkey eyes with experimental glaucoma.

RESULTS

At the late stage of glaucoma, the labeling of collagen type IV and laminin were increased at pre-LC and LC area due to the accumulation of basement membrane-like materials.

CONCLUSION

The changes may be a selective response to elevated intraocular pressure. This response may alter the biochemical composition and the biomechanics of the lamina cribrosa.