Early cathepsin K degradation of type II collagen in vitro and in vivo in articular cartilage.

OBJECTIVE: To characterize the initial events in the cleavage of type II collagen mediated by cathepsin K and demonstrate the presence of the resulting products in human and equine articular osteoarthritic cartilage. DESIGN: Equine type II collagen was digested with cathepsin K and the cleavage products characterized by mass spectrometry. Anti-neoepitope antibodies were raised against the most N-terminal cleavage products and used to investigate the progress of collagen cleavage, in vitro, and the presence of cathepsin K-derived products in equine and human osteoarthritic cartilage. RESULTS: Six cathepsin K cleavage sites distributed throughout the triple helical region were identified in equine type II collagen. Most of the cleavages occurred following a hydroxyproline residue. The most N-terminal site was within three residues of the previously identified site in bovine type II collagen. Western blotting using anti-neoepitope antibodies showed that the initial cleavages occurred at the N-terminal sites and this was followed by more extensive degradation resulting in products too small to be resolved by SDS gel electrophoresis. Immunohistochemical staining of cartilage sections from equine or human osteoarthritic joints showed staining in lesional areas which was not observed in non-arthritic sites. CONCLUSIONS: Cathepsin K cleaves triple helical collagen by erosion from the N-terminus and with subsequent progressive cleavages. The liberated fragments can be detected in osteoarthritic cartilage and may represent useful biomarkers for disease activity.

RADON SURVEY IN SCHOOL AND ESTIMATION OF EFFECTIVE DOSE USING CORRECTED RADON CONCENTRATION.

Radon exposure in schools is different from that in dwellings because the residence pattern is very different each other. So, when effective dose is calculated in schools, different approach should be considered from in dwellings. The aim of this study was to estimate actual effective dose due to inhaled radon considering the residence time in schools. It could help avoid overestimation when effective dose is calculated in schools. The range of radon concentration in 376 schools was 18.1-2810 Bq m-3 and that of annual effective dose was estimated 0.0902-8.92 mSv y-1 considering the residence time in spring and autumn semesters.

The consequence of PRELP overexpression on skin.

PRELP is a member of the small leucine-rich repeat proteoglycan family that is abundantly expressed in many cartilages compared to other connective tissues. To study the consequence of PRELP overexpression in tissues where it is normally expressed at low abundance, transgenic mice were generated in which the human PRELP transgene was placed under control of the CMV promoter. A connective tissue phenotype was observed in the skin, where the organization of collagen fibrils in the dermis was perturbed and the thickness of the hypodermal fat layer was diminished.

Direct temperature measurement.

Hyperthermia has little hope of progressing as a clinical modality without accurate assessment of the temperature distributions obtained. At the present time only direct, invasive temperature-measuring techniques are possible, posing severe limitations. Established techniques for clinical temperature measurement have developed over the past few years, and for both ultrasound and electromagnetic hyperthermia it is possible to get temperature-time profiles at a large number of spatial points. Position uncertainty, thermal conduction smearing, and artifactual heating limit the accuracy to about 0.2 degrees (electromagnetic) or 0.5 degrees (ultrasound), but this is probably less of a hindrance than the inadequate percentage of tumor and normal tissue volume for which achieved temperatures can be documented.

Plasma tocopherol and prevalence of colorectal adenomas in a multiethnic population.

Although vitamin E can block mutagenesis and cell transformation in vitro and can reduce the number of chemically induced colonic adenomas in mice, previous clinical trials have found no protective effect of vitamin E supplements against colorectal adenomas, and epidemiological studies have found only weak protective effects of dietary or plasma alpha-tocopherol against colorectal cancer. We previously examined first diagnosis of colorectal adenomas in a sigmoidoscopy screening population and failed to find a protective effect of dietary vitamin E. Because measurements of dietary intake may not be a good proxy of vitamin E status, we assayed plasma alpha- and gamma-tocopherol concentration for 332 subjects with colorectal adenomas and 363 control subjects from this previous sigmoidoscopy-based study. Increasing alpha-tocopherol and decreasing gamma-tocopherol levels were associated with decreased occurrence of large (> or = 1 cm) but not of small (<1 cm) adenomas; however, after adjustment for potential confounding variables, these trends were not statistically significant. A strong trend (P = 0.02) was observed by using the alpha-tocopherol:gamma-tocopherol ratio, which may be a more sensitive indicator of alpha-tocopherol intake. Subjects in the highest versus lowest quintile of alpha-tocopherol: gamma-tocopherol ratio had an odds ratio of 0.36 (95% confidence interval, 0.14-0.95) for large adenomas. The finding that a high alpha-tocopherol:gamma-tocopherol ratio is associated with decreased occurrence of large, but not of small, colorectal adenomas is consistent with previous findings that alpha-tocopherol may be protective against colon cancer. A high plasma alpha-tocopherol:gamma-tocopherol ratio may be a better predictor of decreased cancer risk than high plasma alpha-tocopherol alone.

Anatomical site-specific modalities for hyperthermia.

The clinical application of hyperthermia in the treatment of deep-seated tumors remains an empirical science. The pleomorphic nature of the neoplasms and the great diversity in the anatomy and physiology of the individual tumor locations make the treatment of nearly every neoplasm a unique challenge. A wide variety of devices is required, both for the administration of hyperthermia and for the measurement of the temperatures achieved. At Stanford University, these include the BSD Medical Corp. annular phased array system, an isospherical ultrasound device, and interstitial radiofrequency for deep heating. Ultrasound transducers and a variety of microwave applicators are used for superficial hyperthermia. Six illustrative case studies, selected from the 91 patients treated in our program since October 1981, are presented, with discussion and comparison of treatment devices. Difficulties in deep heating were encountered in several instances, believed secondary to the thickness of the s.c. fat, the relatively high heat-induced tumor blood flow, and the presence of adjacent bone. It is suggested that ultimate improvement in clinical results will be possible once a better understanding is achieved of such anatomical and physiological factors.

Acetylation polymorphism and prevalence of colorectal adenomas.

Polymorphic N-acetyltransferase (NAT2), an enzyme present in the colon, may effect incidence of colon cancer. Individuals with NAT2 fast acetylator genotypes may have higher colon cancer risks due to faster conversion of certain carcinogens to mutagens. We determined NAT2 genotypes in 447 subjects with distal colon adenomas and in 487 controls. No significant increase in adenoma prevalence among fast acetylators was observed. However, there was a suggestion of ethnic differences in NAT2 effects. For example, white fast acetylators potentially had slightly increased risks for adenomas (odds ratio, 1.29; 95% confidence interval, 0.90-1.84), whereas fast acetylation was potentially protective among blacks (odds ratio, 0.64; 95% confidence interval, 0.32-1.28). The apparent difference between blacks and whites may simply reflect random variation around an overall null effect, or it could represent a real difference. There was preliminary evidence for a possible interaction between NAT2 and the glutathione transferase M1 null genotype. Smokers' adenoma prevalence was 10-fold higher for fast acetylators with the null genotype compared to slow acetylators without the null genotype. Large, multiethnic populations and analysis of combinations of genes for carcinogen metabolism may be needed to further assess the role of NAT2 in colorectal tumorigenesis.

Glutathione transferase (GSTM1) null genotype, smoking, and prevalence of colorectal adenomas.

Colorectal cancer is caused by environmental exposures and genetic predisposition. However, little is known of hereditary factors that influence development of common, non-Mendelian forms of this cancer. Interactions among carcinogen exposure, hereditary variants of enzymes involved in carcinogen metabolism, and other host factors may play a role. Genetic polymorphisms of carcinogen metabolism, such as the glutathione transferase M1 (GSTM1) null genotype, are thus possibly related to cancer risk. The GSTM1 enzyme detoxifies mutagens formed from polycyclic aromatic hydrocarbons which are found in tobacco smoke. We analyzed GSTM1 genotypes and smoking among 488 controls and 446 individuals with a first time diagnosis of colorectal adenomas which are precursors to cancer. Subjects were from two Kaiser Permanente sigmoidoscopy clinics in southern California. We observed no overall effect of the GSTM1 null genotype on the risk for colorectal adenomas (odds ratio, 0.85; 95% confidence interval = 0.65-1.10). The odds ratio for smokers with the null genotype was 2.07 (95% confidence interval = 1.14-3.77) when compared to "never smokers" without the null genotype. Using this same reference group, the odds ratio for smokers without the null genotype was 1.73 (95% confidence interval = 1.03-2.90). These two odds ratios were not significantly different (P = 0.30).

Clinical and microbiological effects of a subantimicrobial dose of oral doxycycline on periodontitis in dogs.

Doxycycline is regarded as an effective treatment for periodontal inflammation. In humans, it has been shown that the long-term administration of a subantimicrobial dose of doxycycline (SDD) does not induce antimicrobial effects on the subgingival microflora and furthermore does not affect antimicrobial susceptibility. The present study was designed to evaluate the influence of oral administration of SDD on normal periodontal microflora and antimicrobial susceptibility in dogs. Experimental periodontitis was induced in 12 experimental dogs using a silk and wire-twisted ligature for 60 days. After the periodontitis induction period, the ligature was removed, and dental cleaning (subgingival and supragingival ultrasonic scaling) was performed. The dogs were randomly assigned to one of two groups: an SDD group with six dogs receiving 2 mg/kg PO once daily and a control group with six dogs receiving a placebo. At weeks 0, 4 and 8, clinical periodontal parameters were evaluated. After the clinical assessments, subgingival plaque was sampled and then cultured in an anaerobic system for one week, and the total anaerobes, Porphyromonas spp., Bacteroides spp. and Pasteurella spp. counts were investigated. Using the agar dilution method, the minimum bactericidal concentration of doxycycline was evaluated and the resistance for doxycycline was monitored during this experimental phase. The clinical periodontal status of the SDD group was significantly improved compared to the control group (P <0.05). Bacterial counts were not significantly different between the two experimental groups (P > 0.05), and antibacterial resistance was not established in the SDD group during the experimental periods (P <0.05). These results suggest that the once daily oral regimen of 2 mg/kg of doxycycline could serve as a SDD in dogs.

Geographical distribution of indoor radon and related geological characteristics in Bonghwa County, a provisional radon-prone area in Korea.

The detailed indoor radon survey was conducted during a year (from September 2012 to August 2013) quarterly in Bonghwa county, one of the provisional radon-prone areas in Korea. The surveyed area was selected on the basis of previously conducted nationwide radon survey results. In order to minimise statistical and environmental uncertainties, ∼3 % of the entire dwellings were carefully selected based on the statistical annual report of Bonghwa county. The measurement is carried out by using solid-state nuclear track detector. The range of indoor radon concentration in each dwelling was 4.36-858 Bq m(-3) and that of annual effective dose due to inhaled radon of the resident in each dwelling was 0.19-23.5 mSv y(-1). Each dwelling was determined for geology criterion using one-way Analysis of Variance for the purpose of comparing indoor radon distribution with geology. Geographical distribution of indoor radon is closely related to the geological characteristics of basement rocks. In addition, the comparison between geographical distribution of indoor radon and terrestrial gamma radiation was done.