The association of meniscal pathologic changes with cartilage loss in symptomatic knee osteoarthritis

OBJECTIVE

To explore the role of meniscal tears and meniscal malposition as risk factors for subsequent cartilage loss in subjects with symptomatic osteoarthritis (OA).

METHODS

Study subjects were patients with symptomatic knee OA from the Boston Osteoarthritis of the Knee Study. Baseline assessments included knee magnetic resonance imaging (MRI) with followup MRI at 15 and 30 months. Cartilage and meniscal damage were scored on MRI in the medial and lateral tibiofemoral joints using the semiquantitative whole-organ magnetic resonance imaging score. Tibiofemoral cartilage was scored on MR images of all 5 plates of each tibiofemoral joint, and the meniscal position was measured using eFilm Workstation software. A proportional odds logistic regression model with generalized estimating equations was used to assess the effect of each predictor (meniscal position factor and meniscal damage as dichotomous predictors in each model) on cartilage loss in each of the 5 plates within a compartment. Models were adjusted for age, body mass index (BMI), tibial width, and sex.

RESULTS

We assessed 257 subjects whose mean +/- SD age was 66.6 +/- 9.2 years and BMI was 31.5 +/- 5.7 kg/m2; 42% of subjects were female, and 77% of knees had a Kellgren/Lawrence radiographic severity grade > or = 2. In the medial tibiofemoral joint, each measure of meniscal malposition was associated with an increased risk of cartilage loss. There was also a strong association between meniscal damage and cartilage loss. Since meniscal coverage and meniscal height diminished with subluxation, less coverage and reduced height also increased the risk of cartilage loss.

CONCLUSION

This study highlights the importance of an intact and functioning meniscus in patients with symptomatic knee OA, since the findings demonstrate that loss of this function has important consequences for cartilage loss.

STK-1, the human homolog of Flk-2/Flt-3, is selectively expressed in CD34+ human bone marrow cells and is involved in the proliferation of early progenitor/stem cells

We cloned the cDNA for stem cell tyrosine kinase 1 (STK-1), the human homolog of murine Flk-2/Flt-3, from a CD34+ hematopoietic stem cell-enriched library and investigated its expression in subsets of normal human bone marrow. The cDNA encodes a protein of 993 aa with 85% identity and 92% similarity to Flk-2/Flt-3. STK-1 is a member of the type III receptor tyrosine kinase family that includes KIT (steel factor receptor), FMS (colony-stimulating factor 1R), and platelet-derived growth factor receptor. STK-1 expression in human blood and marrow is restricted to CD34+ cells, a population greatly enriched for stem/progenitor cells. Anti-STK-1 antiserum recognizes polypeptides of 160 and 130 kDa in several STK-1-expressing cell lines and in 3T3 cells transfected with a STK-1 expression vector. Antisense oligonucleotides directed against STK-1 sequences inhibited hematopoietic colony formation, most strongly in long-term bone marrow cultures. These data suggest that STK-1 may function as a growth factor receptor on hematopoietic stem and/or progenitor cells.

Targeting of lung cancer mutational hotspots by polycyclic aromatic hydrocarbons

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in combustion products of organic matter, including cigarette smoke. Metabolically activated diol epoxides of these compounds, including benzo[a]pyrene diol epoxide (B[a]PDE), have been suggested as causative agents in the development of lung cancer. We previously mapped the distribution of B[a]PDE adducts within the p53 tumor suppressor gene (also known as TP53), which is mutated in 60% of human lung cancers, and found that B[a]PDE adducts preferentially form at lung cancer mutational hotspots (codons 154, 157, 158, 245, 248, and 273). Other PAHs may be important in lung cancer as well.

METHODS

Here we have mapped the distribution of adducts induced by diol epoxides of additional PAHs: chrysene (CDE), 5-methylchrysene (5-MCDE), 6-methylchrysene (6-MCDE), benzo[c]phenanthrene (B[c]PDE), and benzo[g]chrysene (B[g]CDE) within exons 5, 7, and 8 of the p53 gene in human bronchial epithelial cells.

RESULTS

CDE exposure produced only low levels of adducts. Exposure of cells to the other activated PAHs resulted in DNA damage patterns similar to those previously observed with B[a]PDE but with some distinct differences. 5-MCDE, 6-MCDE, B[g]CDE, and B[c]PDE efficiently induced adducts at guanines within codons 154, 156, 157, 158, and 159 of exon 5, codons 237, 245 and 248 of exon 7, and codon 273 of exon 8, but the relative levels of adducts at each site varied for each compound. B[g]CDE, B[c]PDE, and 5-MCDE induced damage at codon 158 more selectively than 6-MCDE or B[a]PDE. The sites most strongly involved in PAH adduct formation were also the sites of highest mutation frequency (codons 157, 158, 245, 248, and 273).

CONCLUSION

The data suggest that PAHs contribute to the mutational spectrum in human lung cancer.

Change in joint space width: hyaline articular cartilage loss or alteration in meniscus?

OBJECTIVE

To explore the relative contribution of hyaline cartilage morphologic features and the meniscus to the radiographic joint space.

METHODS

The Boston Osteoarthritis of the Knee Study is a natural history study of symptomatic knee osteoarthritis (OA). Baseline and 30-month followup assessments included knee magnetic resonance imaging (MRI) and fluoroscopically positioned weight-bearing knee radiographs. Cartilage and meniscal degeneration were scored on MRI in the medial and lateral tibiofemoral joints using a semiquantitative grading system. Meniscal position was measured to the nearest millimeter. The dependent variable was joint space narrowing (JSN) on the plain radiograph (possible range 0-3). The predictor variables were MRI cartilage score, meniscal degeneration, and meniscal position measures. We first conducted a cross-sectional analysis using multivariate regression to determine the relative contribution of meniscal factors and cartilage morphologic features to JSN, adjusting for body mass index (BMI), age, and sex. The same approach was used for change in JSN and change in predictor variables.

RESULTS

We evaluated 264 study participants with knee OA (mean age 66.7 years, 59% men, mean BMI 31.4 kg/m(2)). The results from the models demonstrated that meniscal position and meniscal degeneration each contributed to prediction of JSN, in addition to the contribution by cartilage morphologic features. For change in medial joint space, both change in meniscal position and change in articular cartilage score contributed substantially to narrowing of the joint space.

CONCLUSION

The meniscus (both its position and degeneration) accounts for a substantial proportion of the variance explained in JSN, and the change in meniscal position accounts for a substantial proportion of change in JSN.

Prognosis in cutaneous T-cell lymphoma by skin stage: long-term survival in 489 patients

BACKGROUND

Although a number of studies have documented the long-term survival of patients with cutaneous T-cell lymphoma (CTCL), none have provided data as to the relative survival of all 4 skin stages.

OBJECTIVE

We document survival of CTCL patients by T stage relative to that of an age-, sex-, and race-matched population.

METHODS

The survival of 489 patients with CTCL registered since 1957 was compared with that of a California control population.

RESULTS

For stage T1 (< 10% skin involved) there was no significant difference between the observed and expected survivals. For the other 3 stages the observed survival was significantly inferior to that of the expected survival (P = .002). At 10 years the relative survivals were: T2 (10% or more skin involved) 67.4%, T3 (tumor stage) 39.2%, T4 (generalized erythroderma) 41.0%. T2 plaque stage patients had an inferior relative survival (P = .001), whereas T2 patch stage patients did not. Lymphadenopathy had an unfavorable impact on prognosis. There was a strong trend toward diagnosing CTCL at an earlier stage in more recent years. We estimate that from 15% to 20% of our patients died of CTCL or related complications.

CONCLUSION

The relative survival of CTCL patients worsens with increasing skin stage, although stages T3 and T4 had closely similar survivals. The great majority of patients with CTCL do not die of their disease.

Association of hypogonadism and estradiol levels with bone mineral density in elderly men from the Framingham study

BACKGROUND

Both hypogonadism and low estrogen levels adversely affect bone health in young men. In elderly men, who are at greatest risk for osteoporotic fracture, the influence of hypogonadism on bone mineral density remains unclear, as does the relative effect of estrogen status compared to hypogonadism.

OBJECTIVE

To examine the relation of hypogonadism and estrogen status to bone mineral density in elderly men.

DESIGN

Community-based, prospective cohort study.

SETTING

Framingham, Massachusetts.

PATIENTS

Male participants of the Framingham Study.

MEASUREMENTS

Total testosterone, total estradiol, and luteinizing hormone were measured in participants at all four biennial examinations from 1981 to 1989. Values from at least three of four examinations were averaged. Hypogonadism was defined as a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) or a mean luteinizing hormone level of 20 IU/L or greater. An alternate definition of hypogonadism based only on a mean testosterone level less than 10.4 nmol/L (<3.0 ng/mL) was also used. In 1988-1989, bone mineral density was measured at the proximal femur (femoral neck, Ward triangle, and trochanter) and lumbar spine by using dual-photon absorptiometry and at the radial shaft by using single-photon absorptiometry. The association of hypogonadism with bone mineral density was examined with adjustment for confounders, including estradiol levels. A similar model that adjusted for hypogonadism was used to examine the association of estradiol level (ranked as quartiles) with bone mineral density.

RESULTS

Of 448 men with bone mineral density measurements, 405 had evaluable hormone levels (mean age, 75.7 years [range, 68 to 96 years]); 71 (17.5%) of the 405 men were hypogonadal. Bone mineral density at any site did not significantly differ in hypogonadal men compared with eugonadal men (for example, bone mineral density at the femoral neck was 0.89 g/cm(2) vs. 0.87 g/cm(2), respectively; P > 0.2), even when alternate definitions of hypogonadism were used. In contrast, compared with the lowest estradiol quartile, men with higher estradiol levels had greater mean bone mineral density at all sites (for example, bone mineral density at the femoral neck was 0.84 g/cm(2), 0.88 g/cm(2), 0.86 g/cm(2), and 0.91 g/cm(2) from the lowest to the highest estradiol quartile; P for trend = 0.002). The difference in mean bone mineral density between men in the lowest and those in the highest estradiol quartile levels was similar to the effect of 10 years of aging on bone mineral density.

CONCLUSIONS

In elderly men, hypogonadism related to aging has little influence on bone mineral density, but serum estradiol levels have a strong and positive association with bone mineral density.

Topical corticosteroids for mycosis fungoides. Experience in 79 patients

OBJECTIVE

To determine the effectiveness of topical corticosteroids in the management of mycosis fungoides.

DESIGN

Prospective study.

SETTING

Academic referral center, Veterans Affairs Medical Center, and private practice.

PATIENTS

Seventy-nine patients with patch or plaque stage of mycosis fungoides. Fifty-one were stage T1 (less than 10% of skin involved) and 28 were stage T2 (10% or more of skin involved). Seventy-five had patch-stage and 4 had plaque-stage disease as determined by histological examination.

INTERVENTION

Patients were treated with topical class I to III corticosteroids. Of the stage T1 patients, all used class I corticosteroids, and 4 (8%) also used class II or III corticosteroids. Of the stage T2 patients, 19 (68%) used class I and 12 (43%) used class II or III compounds. Some patients used more than 1 class of corticosteroid. Applications were almost always twice daily. Three stage T1 and 2 stage T2 patients used plastic film occlusion. Baseline and monthly morning serum cortisol levels were obtained during treatment.

MAIN OUTCOME MEASURES

Response to treatment and side effects.

RESULTS

The median follow-up period was 9 months. Thirty-two (63%) of stage T1 patients achieved complete remission and 16 (31%) achieved partial remission, for a total response rate of 48 (94%). The comparable figures for stage T2 patients were 7 (25%), 16 (57%), and 23 (82%), respectively. Responses were determined by clinical examination. Thirty-nine patients achieved clinical clearing. In 7 of these, posttreatment biopsy specimens were obtained, and all showed histological clearing. Reversible depression of serum cortisol levels occurred in 10 (13%). Minor skin irritation occurred in 2 patients and localized, reversible skin atrophy in 1.

CONCLUSION

Topical corticosteroids, especially class I compounds, are an effective treatment for patch-stage mycosis fungoides.

Molecular cloning of cDNA encoding a second cellular retinoic acid-binding protein

The vitamin A derivative retinoic acid is known to be a potent agent for control of differentiation and proliferation of epithelial cells and to exert profound effects on pattern formation during embryogenesis. Its action at the molecular level appears to be mediated by two distinct classes of proteins: a family of nuclear receptors that regulates gene transcription in a ligand-dependent fashion and a small cellular retinoic acid-binding protein (CRABP) for which a precise function remains to be elucidated. In this report, we describe the identification (by molecular cloning of its cDNA) of an isoform of CRABP, referred to as CRABP-II, expressed at high levels during mouse embryogenesis and in adult skin. We also show that CRABP-II mRNA levels are induced by at least 50-fold upon treatment of F9 teratocarcinoma cells with retinoic acid. The up-regulation of the gene encoding CRABP-II by its ligand suggests that CRABP-II might be involved in a feedback regulatory role in the mechanism of action of retinoic acid on cellular differentiation.

The role of vitamin D in corticosteroid-induced osteoporosis: a meta-analytic approach

OBJECTIVE

To determine if vitamin D is more effective than no therapy or calcium alone in the management of corticosteroid-induced osteoporosis, and to determine how vitamin D compares with other osteoporosis therapies, e.g., bisphosphonates, calcitonin, or fluoride, for this condition.

METHODS

We evaluated all formulations of vitamin D, including its active metabolites and analogs. A systematic search for published and unpublished studies was conducted using MEDLINE (1966-December 1997), bibliographic references, abstracts from proceedings of recent national meetings, and contact with pharmaceutical companies and content experts. We included all randomized controlled trials lasting at least 6 months (and reporting extractable results), of patients receiving oral corticosteroids, that compared vitamin D with either 1) no therapy or calcium alone, or 2) bisphosphonates, calcitonin, or fluoride. The primary outcome measure of interest was change in lumbar spine bone mineral density.

RESULTS

We found a moderate beneficial effect of vitamin D plus calcium versus no therapy or calcium alone (9 trials) (effect size 0.60; 95% confidence interval [95% CI] 0.34, 0.85; P < 0.0001). In comparisons of vitamin D with other osteoporosis therapies, bisphosphonates were more effective than vitamin D (6 trials) (effect size 0.57; 95% CI 0.09, 1.05). Calcitonin was similar in efficacy to vitamin D (4 trials) (effect size 0.03; 95% CI -0.39, 0.45). Fluoride was more effective than vitamin D, but there were only 2 trials.

CONCLUSION

Vitamin D plus calcium is superior to no therapy or calcium alone in the management of corticosteroid-induced osteoporosis. Vitamin D is less effective than some osteoporosis therapies. Therefore, treatment with vitamin D plus calcium, as a minimum, should be recommended to patients receiving long-term corticosteroids.

Long-term mortality following fractures at different skeletal sites: a population-based cohort study

Adjusting for age, sex, and precipitating cause, the relative risk of death was increased following fractures at most skeletal sites.

INTRODUCTION

This study aims to determine long-term survival following fractures due to any cause at each skeletal site.

METHODS

In a historical cohort study, 2,901 Olmsted County, MN, USA, residents ≥35 years old who experienced any fracture in 1989-1991 were followed passively for up to 22 years for death from any cause. Standardized mortality ratios (SMRs) compared observed to expected deaths.

RESULTS

During 38,818 person-years of follow-up, 1,420 deaths were observed when 1,191 were expected (SMR, 1.2; 95 % CI, 1.1-1.3). The overall SMR was greatest soon after fracture, especially among the men, but remained elevated for over a decade thereafter. Adjusting for age and sex, relative death rates were greater for pathological fractures and less for severe trauma fractures compared to the fractures due to no more than moderate trauma. In the latter group, long-term mortality was increased following fractures at many skeletal sites. After further adjustment for precipitating cause, overall SMRs were elevated not only following fractures at the traditional major osteoporotic sites (i.e., distal forearm, proximal humerus, thoracic/lumbar vertebrae, and proximal femur) combined (SMR, 1.2; 95 % CI, 1.1-1.3) but also following all other fracture types combined (SMR 1.2; 95 % CI, 1.1-1.4), excluding the hand and foot fractures not associated with any increased mortality.

CONCLUSIONS

The persistence of increased mortality long after the occurrence of a fracture has generally been attributed to underlying comorbidity, but this needs to be defined in much greater detail if specific opportunities are to be identified for reducing the excess deaths observed.

The spectrum of pathogenic mutations in SPINK5 in 19 families with Netherton syndrome: implications for mutation detection and first case of prenatal diagnosis

The Comèl-Netherton syndrome is an autosomal recessive multisystemic disorder characterized by localized or generalized congenital ichthyosis, hair shaft abnormalities, immune deficiency, and markedly elevated IgE levels. Life-threatening complications during infancy include temperature and electrolyte imbalance, recurrent infections, and failure to thrive. To study the clinical presentations of the Comèl-Netherton syndrome and its molecular cause, we ascertained 19 unrelated families of various ethnic backgrounds. Results of initial linkage studies mapped the Comèl-Netherton syndrome in 12 multiplex families to a 12 cM interval on 5q32, thus confirming genetic homogeneity of Comèl-Netherton syndrome across families of different origins. The Comèl-Netherton syndrome region harbors the SPINK5 gene, which encodes a multidomain serine protease inhibitor (LEKTI) predominantly expressed in epithelial and lymphoid tissues. Recently, recessive mutations in SPINK5 were identified in several Comèl-Netherton syndrome patients from consanguineous families. We used heteroduplex analysis followed by direct DNA sequencing to screen all 33 exons and flanking intronic sequences of SPINK5 in the affected individuals of our cohort. Mutation analysis revealed 17 distinct mutations, 15 of which were novel, segregating in 14 Comèl-Netherton syndrome families. The nucleotide changes included four non-sense mutations, eight small deletions or insertions leading to frameshift, and five splice site defects, all of which are expected to result in premature terminated or altered translation of SPINK5. Almost half of the mutations clustered between exons 2 and 8, including two recurrent mutations. Genotype-phenotype correlations suggested that homozygous nucleotide changes resulting in early truncation of LEKT1 are associated with a severe phenotype. For the first time, we used molecular data to perform prenatal testing, thus demonstrating the feasibility of molecular diagnosis in the Comèl-Netherton syndrome.

Cigarette smoking and the risk for cartilage loss and knee pain in men with knee osteoarthritis

OBJECTIVE

To examine the effects of smoking on cartilage loss and pain at the knee in individuals with knee osteoarthritis.

METHODS

159 men with symptomatic knee osteoarthritis who participated in a 30-month, prospective, natural history study of knee osteoarthritis were examined. The more symptomatic knee was imaged using magnetic resonance imaging (MRI) at baseline, and again at 15 and 30 months of follow-up. Cartilage was scored using the Whole-Organ MRI Score semiquantitative method at the medial and lateral tibiofemoral joints and at the patellofemoral joint. At baseline and follow-up visits, the severity of knee pain was assessed using a Visual Analogue Scale pain score (0-100 mm).

RESULTS

Among the 159 men, 19 (12%) were current smokers at baseline. Current smokers were younger (mean (standard deviation (SD)) age 62 (9) v 69 (9) years) and leaner (mean (SD) body mass index (BMI): 28.9 (3.2) v 31.3 (4.8) kg/m(2)) than men who were not current smokers. When adjusted for age, BMI and baseline cartilage scores, men who were current smokers were found to have an increased risk for cartilage loss at the medial tibiofemoral joint (odds ratio (OR) 2.3, 95% confidence interval (CI) 1.0 to 5.4) and the patellofemoral joint (OR 2.5, 95% CI 1.1 to 5.7). Current smokers also had higher adjusted pain scores at baseline (60.5 v 45.0, p<0.05) and at follow-up (59.4 v 44.3, p<0.05) than men who were not current smokers.

CONCLUSIONS

Men with knee osteoarthritis who smoke sustain greater cartilage loss and have more severe knee pain than men who do not smoke.

Assessing forearm fracture risk in postmenopausal women

A diverse array of bone density, structure, and strength parameters were significantly associated with distal forearm fractures in postmenopausal women, but most of them were also correlated with femoral neck areal bone mineral density (aBMD), which provides an adequate measure of bone fragility at the wrist for routine clinical purposes.

INTRODUCTION

This study seeks to test the clinical utility of approaches for assessing forearm fracture risk.

METHODS

Among 100 postmenopausal women with a distal forearm fracture (cases) and 105 with no osteoporotic fracture (controls), we measured aBMD and assessed radius volumetric bone mineral density, geometry, and microstructure; ultradistal radius failure load was evaluated in microfinite element (microFE) models.

RESULTS

Fracture cases had inferior bone density, geometry, microstructure, and strength. The most significant determinant of fracture in five categories were bone density (femoral neck aBMD; odds ratio (OR) per standard deviation (SD), 2.0; 95% confidence interval (CI), 1.4-2.8), geometry (cortical thickness; OR, 1.5; 95% CI, 1.1-2.1), microstructure (structure model index (SMI); OR, 0.5; 95% CI, 0.4-0.7), and strength (microFE failure load; OR, 1.8; 95% CI, 1.3-2.5); the factor-of-risk (applied load in a forward fall / microFE failure load) was 15% worse in cases (OR, 1.9; 95% CI, 1.4-2.6). Areas under receiver operating characteristic curves (AUC) ranged from 0.62 to 0.68. The predictors of forearm fracture risk that entered a multivariable model were femoral neck aBMD and SMI (combined AUC, 0.71).

CONCLUSIONS

Detailed bone structure and strength measurements provide insight into forearm fracture pathogenesis, but femoral neck aBMD performs adequately for routine clinical risk assessment.

Decomposition rates of isothiocyanate conjugates determine their activity as inhibitors of cytochrome p450 enzymes

Thiol conjugates of isothiocyanates (thiol-ITCs) are metabolites of ITCs formed in the mercapturic acid pathway in mammals. They are effective chemopreventive agents in mouse lung tumor bioassays and in other models. Thiol-ITCs are inhibitors of P450s, but it has not been determined if P450 inhibition is due to conjugates themselves or to parent ITCs released by deconjugation reactions. In studies of mechanism of chemopreventive action of thiol-ITCs, rates of deconjugation of Cys, GSH, and N-acetyl-L-cysteine (NAC) conjugates of benzyl isothiocyanate (BITC), phenethyl isothiocyanate (PEITC), 6-phenylhexyl isothiocyanate (PHITC), and sulforaphane (SFN), expressed as the first-order rate constant k(1) and the half-life of decomposition Dt(1/2), were measured in aqueous solutions at pH 7.4 and 37 degrees. The Dt(1/2)s for the Cys conjugates were severalfold shorter than the Dt(1/2)s for respective GSH conjugates, while the Dt(1/2)s for the NAC conjugates were the longest. Cleavage of thiol conjugates was pH dependent, much slower under acidic conditions than at pH 7.4. Inhibition of P450 enzymes by thiol-ITCs was followed using PROD (pentoxyresorufin O-dealkylation) for P450 2B1 and EROD (ethoxyresorufin O-dealkylation) for P450 1A1. The inhibition of PROD and EROD by aqueous thiol-ITCs increased with preincubation time and was roughly parallel to the extent of decomposition of the conjugate that had occurred, indicating that both potency of the respective parent ITC and the rate of reductive cleavage of the conjugate influenced enzyme inhibition. In the presence of 250-1000 microM GSH, comparable to physiological levels, rates of deconjugation of thiol-ITCs were markedly reduced; inhibition of PROD was also proportionately reduced. Slow rates of decomposition of thiol-ITCs anticipated in plasma and tissues suggests that inhibition of P450 enzymes involved in carcinogen activation by ITCs released from thiol-ITCs may not be a principal mechanism for their tumor inhibitory activity; other mechanisms probably contribute to their chemopreventive activity.

Effect of caffeic acid esters on carcinogen-induced mutagenicity and human colon adenocarcinoma cell growth

Propolis, a honey bee hive product, is thought to exhibit a broad spectrum of activities including antibiotic, antiviral, anti-inflammatory and tumor growth inhibition; some of the observed biological activities may be due to caffeic acid (cinnamic acid) esters that are present in propolis. In the present study we synthesized three caffeic acid esters, namely methyl caffeate (MC), phenylethyl caffeate (PEC) and phenylethyl dimethylcaffeate (PEDMC) and tested them against the 3,2'-dimethyl-4-aminobiphenyl, (DMAB, a colon and mammary carcinogen)-induced mutagenicity in Salmonella typhimurium strains TA 98 and TA 100. Also, the effect of these agents on the growth of human colon adenocarcinoma, HT-29 cells and activities of ornithine decarboxylase (ODC) and protein tyrosine kinase (PTK) was studied. Mutagenicity was induced in Salmonella typhimurium strains TA 98 and TA 100 plus S9 activation using 5 and 10 micrograms DMAB and antimutagenic activities of 0-150 microM MC, 0-60 microM PEC and 0-80 microM PEDMC were determined. The results indicate that MC, PEC and PEDMC were not mutagenic in the Salmonella tester system. DMAB-induced mutagenicity was significantly inhibited with 150 microM MC, 40-60 microM PEC and 40-80 microM PEDMC in both tester systems. Treatment of HT-29 colon adenocarcinoma cells with > 150 microM MC, 30 microM PEC and 20 microM PEDMC significantly inhibited the cell growth and syntheses of RNA, DNA and protein. ODC and PTK activities were also inhibited in HT-29 cells treated with different concentrations of MC, PEC and PEDMC. These results demonstrate that caffeic acid esters which are present in Propolis possess chemopreventive properties when tested in short-term assay systems.

Rapid single-dose model for lung tumor induction in A/J mice by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and the effect of diet

This paper describes the development of a relatively rapid single-dose model for induction of lung adenomas in female A/J mice by the tobacco-specific nitrosamine 4-(methylnitros-amino)-1-(3-pyridyl)-1-butanone (NNK). Mice maintained on AIN-76A semi-synthetic diet were given a single i.p. dose of 2.5, 5 or 10 mumol NNK in saline and killed 3-7 months later. Maximum lung tumor induction, measured by lung tumors per mouse (tumor multiplicity), occurred in 3.5 months. There was no significant increase in tumor multiplicity between 3.5 and 7 months. Four months after treatment, numbers of lung tumors per mouse were 11.9 +/- 1.0 (10 mumol NNK), 3.6 +/- 0.4 (5 mumol), 0.9 +/- 0.4 (2.5 mumol) and 0.07 +/- 0.1 (saline). Lung tumor multiplicity in mice treated with a single dose of 10 mumol NNK and maintained on AIN-76A diet was significantly higher (8.3 +/- 0.5) than in mice treated with NNK and maintained on NIH-07 diet (2.5 +/- 0.3). The results of this study establish a useful bioassay for identification of compounds that can modify NNK-induced lung tumorigenesis.

Fidelity of translesional synthesis past benzo[a]pyrene diol epoxide-2'-deoxyguanosine DNA adducts: marked effects of host cell, sequence context, and chirality

We have used a site-specific approach to investigate the mutagenic potential of (+)- and (-)-trans-anti-benzo[a]pyrene diol epoxide (BPDE) DNA adducts. Oligodeoxyribonucleotides (5'TCCTCCTG1G2-CCTCTC), modified at the exocyclic amino groups of G1 or G2, were incorporated into a single-stranded shuttle vector and introduced into Escherichia coli or simian kidney (COS) cells. This experimental system permits translesional synthesis to proceed in the absence of DNA repair. The presence of (+)- or (-)-BPDE-N2-dG adducts strongly inhibited translesional synthesis in E. coli; induction of cellular SOS functions reduced this blocking effect. Vectors containing (+)-BPDE adducts at G1 or G2 generated mutation frequencies of 19% and 3%, respectively; these values were not altered significantly by induction of SOS functions. In COS cells, (+)-BPDE-modified vectors generated mutation frequencies of 13% at G1 and 45% at G2. In E. coli, the (-)-BPDE adduct generated mutation frequencies of < or = 2% at G1 and G2 and, in COS cells, 13% at G1 and 21% at G2. The predominant mutations in E. coli and COS cells were G-->T transversions targeted to the site of the lesion; however, when G2 was modified, a significant number of targeted G-->A and G-->C mutations were observed in COS cells. We conclude from this study that (+)-and (-)-BPDE-N2-dG adducts pair preferentially to dCMP and dAMP during translesional synthesis in a process that is strongly influenced by the stereochemistry of the adduct, by the bases flanking the lesion, and by host cell factors.

Contrast, coagulation, and fibrinolysis

Some adverse clinical effects of intravascular radiologic contrast agents have been attributed to their interference with the normal hemostatic processes. This study compares the effects of the low osmolality agents with those of the conventional agents by in vitro studies of platelet function, fibrin formation, and fibrinolytic activation. In various degrees, all the contrast agents studied inhibit platelet aggregation and fibrin formation but show virtually no direct activation of fibrinolysis. The new low osmolality agents generally show lesser inhibitory effects on the hemostatic mechanisms. Some clinical implications are discussed.

Dose-response study of the carcinogenicity of tobacco-specific N-nitrosamines in F344 rats

Tobacco and tobacco smoke contain relatively high amounts of four tobacco-specific N-nitrosamines. Of these, N-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and N'-nitrosoanatabine (NAT) were bioassayed at three dose levels by subcutaneous injections into male and female F344 rats in 60 subdoses amounting in total to 9,3, and 1 mmol/kg. Compared with the solvent control group (trioctanoin), both NNN and NNK induced significant numbers of tumors of the nasal cavity (P less than 0.01) at all three dose levels in both male and female rats. Significant numbers of tumors were also induced by NNK in the lung at all three dose levels and in the liver at the highest dose level (P less than 0.05). In addition to nasal tumors NNN also induced esophageal tumors at a significant rate in male rats at the high and medium dose levels and in female rats at the high level (P less than 0.05); NAT was inactive at the three doses tested. Bioassays at lower dose levels as well as biochemical studies are strongly indicated for NNN and NNK since these nitrosamines occur in relatively high amounts in both chewing tobacco and tobacco smoke.

Tumorigenicity in newborn mice of fjord region and other sterically hindered diol epoxides of benzo[g]chrysene, dibenzo[a,l]pyrene (dibenzo[def,p]chrysene), 4H-cyclopenta[def]chrysene and fluoranthene

Diol epoxides of benzo[g]chrysene, dibenzo[a,l]pyrene (dibenzo[def,p]chrysene), 4H-cyclopenta[def]chrysene and fluoranthene were tested for tumorigenicity in newborn mice. The compounds tested were racemic trans-11,12-dihydroxy-anti-13,14-epoxy-11,12,13, 14-tetrahydrobenzo[g]-chrysene (BgCDE), trans-11, 12-dihydroxy-anti-13,14-epoxy-11,12,13,14-tetrahydrodibenzo [a,l]pyrene (DB[a,l]PDE), trans-1,2-dihydroxy-anti-3, 3a-epoxy,1,2,3,3a-tetrahydro-4H-cyclopenta[def]chrysene (C[def]C-1,3a-DE), trans-6,7-dihydroxy-anti-8,9-epoxy-10b,1, 2,3-tetrahydrofluoranthene (FDE). BgCDE and DB[a,l]PDE are fjord region diol epoxides and their tumorigenic activities were compared to those of trans-3,4-dihydroxy-anti-1, 2-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene (BcPDE), a fjord region diol epoxide with known high tumorigenicity and trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9, 10-tetrahydrobenzo[a]-pyrene (BPDE), a highly tumorigenic bay region diol epoxide. The protocol called for testing of each compound at a total dose of 25 nmol per mouse, administered on days 1, 7 and 15 of life, with killing at age 35 weeks. BgCDE had similar activity as BcPDE for induction of lung tumors and was more active than BcPDE for induction of liver tumors in male mice. Both compounds were significantly more tumorigenic than BPDE. DB[a,l]PDE was highly toxic. All mice died within 1 week of the first dose. It was then tested in a second study using total doses of 5 and 1 nmol per mouse. Only the first dose of the intended 5 nmol total dose was given due to toxicity. The full course of doses with a total of 1 nmol per mouse was administered; DB[a,l]PDE induced a significant incidence and multiplicity of lung tumors and, in male mice, liver tumors at both doses. These results demonstrate that fjord diol epoxides are highly active tumorigens in newborn mice, with activity greater than that of the most active unsubstituted bay region diol epoxide, BPDE. C[def]C-1-3a-DE and C[def]-6-9-DE were compared to trans-1,2-dihydroxy-anti-3, 4-epoxy-1,2,3,4-tetrahydrochrysene (CDE), at a total dose of 500 nmol per mouse. FDE was also tested at this dose. The most active compound among the chrysene derivatives was C[def]C-1-3a-DE, followed by C[def]C-6-9-DE and CDE. C[def]C-1-3a-DE has a sterically constrained bay region, in which the benzylic carbon of the tri-substituted epoxide ring is part of a fused ring system. This feature is also present in FDE, which and considerable tumorigenic activity, greater than that of CDE in lung and greater than any of the chrysene derivatives in liver.(ABSTRACT TRUNCATED AT 400 WORDS)

Retinoic acid inhibition of cell cycle progression in MCF-7 human breast cancer cells

Cell cycle analysis indicates that retinoic acid (RA) inhibition of MCF-7 cell growth occurs through induction of G1 arrest with a concomitant reduction in the proportion of cells in S and G2 + M phases. RA did not affect cyclins D1, A, and E and cyclin-dependent kinase 2 (CDK2) expression, but significantly reduced cyclin D3 and CDK4 expression after 24 h. RA also inhibited cyclin B1 and CDC2 expression, possibly responsible for the reduction of the proportion of cells in G2 + M and S phases. RA did not induce p16 and p27 expression, but obviously reduced p21 level in MCF-7 cells. The retinoid markedly reduced pRB protein level and abrogated pRB phosphorylation after 48 h; it also reduced transcription factor E2F1 expression at both the mRNA and protein levels. E2F1 promoter activity was reduced by 60%, which is probably responsible, at least in part, for the reduction of E2F1 expression in RA-treated MCF-7 cells. These observations demonstrate a marked effect of RA on some of the key cell cycle regulatory proteins in MCF-7 cells. Cyclin D3 and CDK4 are likely the early targets of RA, followed by reduced pRB expression and phosphorylation, as well as by the inhibition of the E2F1 transcription factor which controls progression from G1 to S phase. Most of these events precede the observed reduction in MCF-7 cell growth, which begins at Day 3 of RA treatment.

Synthesis of (-)-[4-3H]epigallocatechin gallate and its metabolic fate in rats after intravenous administration

Because a great deal of attention has been focused on the metabolism of (-)-epigallocatechin gallate (EGCg), quantitative analysis of this compound is required. For this purpose we developed a method of chemical synthesis of [4-(3)H]EGCg. Synthesized [4-(3)H]EGCg showed 99.5% radiochemical purity and a specific activity of 13 Ci/mmol. To clarify the excretion route of EGCg, the radioactivity levels of bile and urine were quantified after intravenous administration of [4-(3)H]EGCg to bile-duct-cannulated rats. Results showed that the radioactivity of the bile sample excreted within 48 h accounted for 77.0% of the dose, whereas only 2.0% of the dose was recovered in the urine. The excretion ratio of bile to urine was calculated to be about 97:3. These results clearly showed that bile was the major excretion route of EGCg. Time-course analysis of the radioactivity in blood was also performed to estimate the pharmacokinetic parameters following intravenous administration of [4-(3)H]EGCg. In addition, EGCg metabolites excreted in the bile within 4 h after the intravenous dose of [4-(3)H]EGCg were analyzed by HPLC. The results showed that 4',4"-di-O-methyl-EGCg was present in the conjugated form and made up about 14.7% of the administered radioactivity.

Mutagenic potential of stereoisomeric bay region (+)- and (-)-cis-anti-benzo[a]pyrene diol epoxide-N2-2'-deoxyguanosine adducts in Escherichia coli and simian kidney cells

We have investigated the mutagenic potential of site-specifically positioned DNA adducts with (+)- and (-)-cis-anti stereochemistry derived from the binding of r7,t8-dihydroxy-t9,10-epoxy-7,8,9, 10-tetrahydrobenzo[a]pyrene (BPDE) to N2-2'-deoxyguanosine (G1 or G2) in the sequence context 5'TCCTCCTG1 G2CCTCTC. BPDE-modified oligodeoxynucleotides were ligated to a single-stranded DNA vector and replicated in Escherichia coli or simian kidney (COS7) cells. The presence of (+)- or (-)-cis adduct strongly reduced the yield of transformants in E. coli, and the yield was improved by the induction of SOS functions. Both adducts were mutagenic in E. coli and COS cells, generating primarily G --> T transversions. In E. coli, the (-)-cis adduct was more mutagenic than the (+)-cis adduct, while in COS cells, both adducts were equally mutagenic. These results were compared with those obtained with stereoisomeric (+)- and (-)-trans adducts [Moriya, M., et al. (1996) Biochemistry 35, 16646-16651). In E. coli, cis adducts, especially (-)-cis adducts, are consistently more mutagenic than the comparable trans adduct. In COS cells, trans adducts yield higher frequencies of mutations than the two cis adducts and, with the exception of the high-mutation frequency associated with the (+)-trans adduct at G2, relatively small differences in mutation frequencies are observed for the three other adducts. In E. coli, mutation frequency is a pronounced function of adduct stereochemistry and adduct position. These findings suggest that the fidelity of translesional synthesis across BPDE-dG adducts is strongly influenced by adduct stereochemistry, nucleotide sequence context, and the DNA replication complex.