Multisite musculoskeletal pain in adolescence as a predictor of medical and social welfare benefits in young adulthood: The Norwegian Arctic Adolescent Health Cohort Study.

BACKGROUND: Pain in adolescence is associated with mental health problems, the main reason for work disability in young adults. This study explores the relationship between multisite musculoskeletal pain in adolescence and later medical (sickness and medical rehabilitation benefits) and social welfare benefits, adjusted for sociodemographic, adolescent psychosocial and mental health problems. METHODS: Data were obtained by linkage between the National Insurance Registry (2003-11) and the Norwegian Arctic Adolescent Health Study, a school-based survey in North Norway (2003-05), accepted by 3987 fifteen- to sixteen-year-olds (68% of the total population). The start of the follow-up time was July 1st of the corresponding year the participants responded to the health study. Musculoskeletal pain was measured by the number of musculoskeletal pain sites. RESULTS: We found a positive linear relationship between adolescent musculoskeletal pain sites and the occurrence of medical and social welfare benefits in young adulthood (p ≤ 0.001). Adolescent musculoskeletal pain was a significant predictor of sickness (p < 0.001) and social welfare benefits in females (p = 0.036), when adjusted for adolescent psychosocial and mental health problems. The most important adolescent psychosocial predictors were externalizing problems, less parental involvement and adverse life events. CONCLUSION: Adolescent multisite musculoskeletal pain was found to be an important predictor of later sickness and social welfare benefit receipt from adolescence to young adulthood. SIGNIFICANCE: Adolescents with multisite musculoskeletal pain are at substantially increased risk of health and social difficulties into young adulthood. Identification and interventions for these adolescent problems could alleviate this risk and be a sound socioeconomic investment.

From hit to lead. Combining two complementary methods for focused library design. Application to mu opiate ligands.

Compound 1 obtained by random screening and displaying a micromolar activity on the mu opiate receptor was chosen as a starting point for optimization. Two complementary concepts of similarity were used for the design of analogues and compared. These are based, respectively, on a computer-aided comparison of pharmacophoric patterns and on topological similarity. The structure-activity relationships are discussed in light of both similarity concepts. Compound 40, an N-methyl-3-(4-oxo-1-phenyl-1,3,8-triazaspiro[4.5]decyl)acetamide derivative, designed by combining the structure-activity relationships enlightened by each method, has a subnanomolar affinity for mu (h) receptor (IC(50) = 0.9 nM). It is a promising lead, allowing the design of a new series of analogues substituted at the N-3 of the spirocycle moiety.

From hit to lead. Analyzing structure-profile relationships.

Two compounds, obtained by random screening, and displaying micromolar activities on the mu opiate receptor were used as starting points for optimization. In that work, the traditional concept of the activity of a compound (related to one or a few targets) was extended to the comprehensive pharmacological profile of that compound on more than 70 receptors, transporters, and channels relevant to a CNS-oriented project. Using the two complementary design strategies based on two similarity concepts described in the previous paper, we have obtained analogues with IC(50) values ranging between 0.9 nM and a few micromolar on the mu receptor and displaying qualitatively different profiles. We discuss here, both on a case-by-case basis and from a statistical standpoint, the pharmacological profiles in light of the two similarity concepts.

Evaluation of a clinical index among adult contacts of children with tuberculosis in rural Haiti.

OBJECTIVE: To analyze the prevalence of symptoms among adults with and without tuberculosis who were household contacts of children <6 years old with tuberculosis in rural Haiti. DESIGN: An analytic group comparison study to determine whether a clinical index questionnaire (previous tuberculosis diagnosis, previous tuberculosis treatment, cough >1 month, coughing up of blood in the past year, fever >1 month and weight loss in the past year), administered to adults accompanying the child to the hospital can identify which adult household contacts have pulmonary tuberculosis. Household contacts then completed the clinical index and underwent chest X-ray and sputum smear examination. RESULTS: Thirty-two children had 109 adult household contacts. Of these, 56 completed evaluation and nine had pulmonary tuberculosis. Proxy report (OR 36.6, 95%CI >2.3, P = 0.004) was better than self report (OR 2.9, 95%CI >0.36, P = 0.44) in predicting clinical tuberculosis. Investigating adults with a positive clinical index by proxy would have reduced from 26 to 11 those investigated, and no cases of pulmonary tuberculosis would have been missed. CONCLUSION: In rural Haiti, clinical index by proxy by the adult accompanying the child to the hospital can identify which adult household contacts should be investigated for pulmonary tuberculosis.

Transplacental pharmacokinetics and teratogenicity of a single dose of retinol (vitamin A) during organogenesis in the mouse.

Pregnant mice received 10 or 100 mg retinol/kg body wt. by gavage on day 11 of gestation (plug day = day 0). One group of animals was used for a pharmacokinetic study. At various times after dosing, plasma and tissue samples were collected and analyzed by HPLC for retinyl esters, retinol, 13-cis- and all-trans-retinoic acid and 13-cis-4-oxo and all-trans-4-oxoretinoic acid. In the other group the fetuses were removed on day 18 and examined for malformations. After 10 mg/kg retinol, no teratogenic effect was observed. The pharmacokinetic investigation revealed a moderate increase of retinyl esters, retinol and all-trans-retinoic acid in plasma, embryonic tissue, placenta, yolk sac membranes and extraembryonic fluid. A high incidence of severe fetal malformations occurred after 100 mg/kg retinol. These malformations included limb defects (81% of fetuses) and cleft palate (55% of fetuses) which are characteristically found after administration of a single teratogenic dose of an active retinoid on day 11 of gestation. The concentration-time profile of retinoids after 100 mg/kg on day 11 showed a pronounced increase of retinyl esters and retinol in all compartments including the embryo and a massive generation of the polar metabolites all-trans-retinoic acid and all-trans-4-oxoretinoic acid. These polar metabolites were found in the embryo with peak concentrations of 327 +/- 115 and 143 +/- 20.7 ng/g (mean +/- SE) wet tissue, respectively. It is likely that all-trans-retinoic acid and all-trans-4-oxoretinoic acid, both well-known teratogens, largely contributed to the teratogenic outcome. The in-vivo oxidation of retinol may be an important factor in the teratogenic activity of high doses of vitamin A.

Vitamin (A and D)-induced premature physeal closure (hyena disease) in calves.

Hypervitaminosis A and D is a potential cause of "hyena disease" in cattle, which results from premature growth-plate closure in long bones of calves. This study showed that vitamin A induced growth-plate closure if calves were given an intramuscular injection of vitamins A and D (2,000,000 IU and 300,000 IU, respectively) on the first day after birth and, in addition, vitamin A (30,000 IU/kg body weight) in a water dispersible form was added to the milk substitute daily. Gross lesions were observed in the proximal tibial growth plates of each of seven calves after 3 weeks of vitamin-A treatment. Microscopical examination showed commencing premature growth-plate closure in the proximal tibia at 2 weeks. After one week, the growth plate showed focal thinning, and there was premature endochondral ossification of columnar cartilage. Longitudinal bone growth was dramatically reduced before growth plate closure at one week (25 microns/day in a treated animal versus 136 microns/day in a control). Liver concentrations of retinol and retinyl palmitate became strikingly elevated at on week, and thereafter increased slowly until the third week. Elevation of plasma retinol and retinyl palmitate was rapid, reaching a maximum on day 10. Plasma all-trans-retinoic acid was undetectable in many samples from treated animals, but plasma concentrations of derivatives of retinoic acid (9-cis-retinoic acid, 13-cis-retinoic acid, 13-cis-4-oxoretinoic acid, and 9, 13 dicis-retinoic acid) were elevated. The vitamin-A intake required to induce growth-plate closure in calves was found to be exceedingly high. Vitamin-A toxicity must be considered as a potential cause of hyena disease, but it would seem likely that other factors also play a role.

A rare mutation in the amelogenin gene and its potential investigative ramifications.

Over the past few years, the Australian forensic science community has adopted a common methodology and technology in the application of DNA profiling for investigative and forensic purposes. The ultimate objective of this initiative is the establishment of a national DNA database similar to that used in the UK. An integral part of this methodology is the use of "Profiler Plus," a nonaplex of STRs combined with amelogenin, a locus utilized for sex determination. This paper reports the results from a case where a mutation in the annealing region of the amelogenin primers appears to have resulted in the failure to amplify the amelogenin Y-homolog from a phenotypically normal male. The result was confirmed using two different primer sets that amplify different regions of the amelogenin gene. This situation suggests that the genetic determination of sex based on the amelogenin sequences from specimens of unknown origin, such as crime scene samples, should not be considered infallible.

An in vivo model of femtosecond laser intrastromal refractive surgery.

BACKGROUND AND OBJECTIVE: To develop an animal model for evaluation of femtosecond laser intrastromal refractive surgery. METHODS: Intrastromal photodisruption was performed in New Zealand Albino rabbits using a femtosecond laser system. This surgical pattern consisted of a 100 microm-tick pyramid of laser pulses starting 180 microm below the corneal surface. Animals underwent serial slit lamp examinations and corneal thickness measurements at 1,3,7,14, and 28 days, then monthly up to 1 year. RESULTS: Approximately 70 microm of central corneal thinning were seen at 1 week, remaining stable up to 7 months. CONCLUSIONS: Intrastromal photodisruption with femtosecond lasers produced consistent changes in corneal thickness without loss of corneal transparency. These changes were more stable than those produced with excimer laser procedures in a similar animal model.

The contribution of DNA to the disaster victim identification (DVI) effort.

As part of the disaster victim identification (DVI) response to the 2009 Victorian bushfires disaster, a number of scientific disciplines contributed to the human identification process--forensic pathology, anthropology and odontology, as well as fingerprinting and DNA profiling. The DNA laboratory received 182 post-mortem (PM) samples from 120 DVI cases and 236 reference samples corresponding to 163 missing persons (and two non-DVI cases). DNA analysis yielded full DNA profiles for 102 DVI cases and 190 ante-mortem (AM) samples (relating to all 163 missing persons), respectively. Subsequent comparison of DNA profiles, through direct and kinship matching, resulted in the submission of 76 DNA reports to the DVI Reconciliation Centre which assisted in the identification of 67 deceased. This paper describes the contribution of DNA analysis towards the DVI response to the 2009 Victorian bushfires disaster.

Differential teratogenesis of all-trans-retinoic acid administered on gestational day 9.5 to SWV and C57BL/6N mice: emphasis on limb dysmorphology.

BACKGROUND: Mouse strain differences in teratologic response are well documented. However, because retinoids cause similar malformation syndromes across many species, the strain differences may be predicted to be minimal. The goals of this study were to characterize and explain the differences between the C57BL/6N and SWV mouse strains in terms of all-trans-retinoic acid (RA)-induced teratologic effects at the time of gestation that cause postaxial forelimb ectrodactyly. METHODS: Visceral and skeletal malformations were determined by Wilson's sectioning and double-staining techniques, respectively; developmental staging was performed according to the somite count; and retinoid concentrations were assessed by HPLC. RESULTS: C57BL/6N mice were more susceptible than SWV mice to induction of embryolethality, cardiovascular defects, and forelimb ectrodactyly, whereas the opposite was true for the induction of ear, thymus, and tail agenesis, and cleft palate, gastroschisis, and anal atresia. As determined by somite counts, 1 strain intercross was developmentally advanced compared to the parental strains and the reciprocal cross. Retinoid susceptibility was equivalent between the reciprocal crosses for some malformations and determined by the maternal genotype for others. Toxicokinetic experiments showed that whole-embryo peak retinoid concentrations did not differ between the strains, but the area under the curve (AUC) for all-trans-RA was 1.3 times higher in C57BL/6N than in SWV embryos. CONCLUSIONS: The malformation spectrum induced by RA was strain-specific, and the strain sensitivity for forelimb ectrodactyly was consistent with all previously tested teratogenic agents (i.e., C57BL/6N was more sensitive than SWV). The strain differences in teratologic effects were not explained by developmental timing differences or toxicokinetic differences at the whole-embryo level.

Vitamin A supplementation increases levels of retinoic acid compounds in human plasma: possible implications for teratogenesis.

The concentrations of retinoic acid compounds were monitored by a newly developed highly sensitive HPLC procedure in plasma of six volunteers who received 833 IU vitamin A per kg body weight per day during a 20-day period. There was a significant increase of all-trans-retinoic acid (two-fold), 13-cis-retinoic acid (7-fold) and 13-cis-4-oxoretinoic acid (5-fold) over endogenous plasma levels of these retinoids. The same compounds had previously been found after treatment with the teratogenic drug isotretinoin (Roaccutan, Accutane). Our results raise the possibility that high vitamin A intake may carry a teratogenic risk attributable to increased levels of retinoic acid compounds generated from retinol by metabolic processes.

Identification and quantitation of all-trans- and 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid in human plasma.

Human plasma was analyzed by high performance liquid chromatography for the presence of retinoic acid and 4-oxoretinoic acid isomers. Peaks that coeluted with the reference compounds all-trans-retinoic acid, 13-cis-retinoic acid, and 13-cis-4-oxoretinoic acid were routinely observed in human plasma. These retinoids were unequivocally identified by the following methods: comigration with reference compounds under several high performance liquid chromatographic conditions; comparison of ultraviolet spectra with those of reference compounds; derivatization with diazomethane and coelution of the methyl esters with reference compounds in a high performance liquid chromatographic system as well as in a gas chromatography system with a mass selective detector. In vitro formation of 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid as artifacts during the analytical procedure was excluded by control experiments. The mean plasma concentrations of the vitamin A metabolites in ten male volunteers were: all-trans-retinoic acid: 1.32 +/- 0.46 ng/ml; 13-cis-retinoic acid: 1.63 +/- 0.85 ng/ml; and 13-cis-4-oxoretinoic acid: 3.68 +/- 0.99 ng/ml. After oral dosing with vitamin A (833 IU/kg body weight) in five male volunteers, mean plasma all-trans-retinoic acid increased to 3.92 +/- 1.40 ng/ml and 13-cis-retinoic acid increased to 9.75 +/- 2.18 ng/ml. Maximal plasma 13-cis-4-oxoretinoic acid concentrations (average 7.60 +/- 1.45 ng/ml) were observed 6 h after dosing which was the last time point in this study. Concentrations of all-trans-4-oxoretinoic acid were low or not detectable. Our findings suggest that, in addition to all-trans-retinoic acid, 13-cis-retinoic acid and 13-cis-4-oxoretinoic acid are present in normal human plasma as metabolites of vitamin A.

Effects of two oral antimycotics, ketoconazole and fluconazole, upon steroidogenesis in rat adrenal cells in vitro.

Rat adrenal cells were incubated with various concentrations of two orally active azole antimycotics in order to evaluate the effects on steroidogenesis. The first compound was ketoconazole, a well-known inhibitor not only of fungal cytochrome P-450 but at higher concentrations also of mammalian cytochrome P-450 dependent enzymes. The second was fluconazole, a newly developed oral antimycotic with a triazole structure, which likewise inhibits fungal cytochrome P-450. The influence of both drugs on mammalian cytochrome P-450 dependent enzymes was investigated in this study. Ketoconazole inhibited ACTH-stimulated corticosterone (IC50 = 0.9 microM) and aldosterone secretion (IC50 = 1.4 microM) and enhanced 11-deoxycorticosterone output at low concentrations but reduced it at higher concentrations. Radiotracer experiments with [3H]pregnenolone or [3H]11-deoxycorticosterone as exogenous substrates revealed a 50% inhibition of the oxidative substrate metabolism at about 1 microM ketoconazole. These effects could also be observed with fluconazole but occurred at concentrations approximately two orders of magnitude higher as compared to ketoconazole. We conclude that fluconazole has a much higher selectivity for fungal cytochrome P-450 than ketoconazole. The order of sensitivity of the cytochrome P-450 dependent enzymes of rat adrenal steroidogenesis to ketoconazole was the 11 beta/18-hydroxylase, the cholesterol side chain cleavage enzyme and the 21-hydroxylase with decreasing sensitivities.

Embryonic delivered dose of isotretinoin (13-cis-retinoic acid) and its metabolites in hamsters.

All-trans-retinoic acid (all-trans-RA) is required in normal embryogenesis and both deficiency and excess are teratogenic. Isotretinoin (13-cis-RA) is teratogenic in all species examined; based on administered dose, humans appear most sensitive, followed by (in order or decreasing sensitivity) monkey, rabbit, hamster, mouse, and rat. Identification of the teratogenic threshold in these species is difficult because RAs are normal physiologic constituents. The rabbit no-observed-adverse-effect-level (NOAEL) and lowest-observed-adverse-effect-level (LOAEL) administered doses (3 and 15 mg/kg/day, respectively, on gestation Days 8-11) are less than the corresponding values in hamster (7.5 and 37.5 mg/kg/day, respectively, on gestation Days 7 and 8), but drawing conclusions from administered dose alone ignores differences in absorbed, metabolized, and embryonic delivered dose. Therefore, distribution and metabolism studies of 13-cis-RA at the NOAEL and LOAEL in pregnant hamsters were performed and plasma and tissue concentrations of parent compound and metabolites were compared to those found in rabbits. Metabolites of 13-cis-RA common to all species include three RAs (all-trans-RA, all-trans-4-oxoRA, 13-cis-4-oxoRA) and the glucuronide conjugate of 13-cis-RA (13-cis-RAG). As in rabbits, we found 13-cis-4-oxoRA also to be the major metabolite of 13-cis-RA in hamster plasma, peripheral tissues, and embryo. Of maternal tissues, peak 13-cis-RA concentrations were highest in liver. Total concentration of RA (13-cis-RA + 13-cis-4-oxoRA + all-trans-RA + all-trans-4-oxoRA) per gram of wet tissue was greatest in maternal liver, followed by that in lung, adipose tissue, muscle, kidney, and brain. At the NOAEL, total RA plasma Cmax in hamster was 6 times that in rabbit; at the LOAEL, hamster plasma total RA Cmax was 4 times that in rabbit. Hamster absorbed and metabolized dose (as AUC of plasma total RA) at the NOAEL and LOAEL was 2.6 and 2.4 times that in rabbit, respectively. In the embryo, hamster total RA Cmax was 2.7 times (at NOAEL) and 2.6 times (at LOAEL) that in rabbit. However, embryonic delivered dose (total RA AUC in hamster and rabbit embryo, respectively) at the NOAEL (2.08 and 2.14 microg . hr.g-1) and LOAEL (5.34 and 5.54 microg . hr . g-1) was virtually identical. Embryonic AUCs in hamster and rabbit for all-trans-RA and all-trans-4-oxoRA, metabolites which transactivate directly the nuclear RA receptors (RARs), were also very similar at the NOAEL (0.66 and 0.81 microg . hr g-1) and at the LOAEL (1.14 and 1.32 microg . hr g-1). Based on embryonic delivered dose, we suggest that 13-cis-RA is an equipotent teratogen in hamster and rabbit.

[Plasma level and metabolism of vitamin A (Vitadral) in women of reproductive age]. / Untersuchungen über Plasmaspiegel und Metabolismus von Vitamin A (Vitadral) bei Frauen im fertilen Alter.

Using a sensitive HPLC method, plasma concentrations of vitamin A and metabolites were measured from 6 female volunteers who had taken once daily 0.46 mg/kg BW retinol palmitate (Vitadral) for 10 days. The metabolites all-trans- and 13-cis-retinoic acid were increased significantly (2- and 5-fold, resp.) 6 h after the ist intake. 13-cis-4-oxo retinoic acid the 10th intake in the morning of the 10th day (9.22 +/- 2.77 ng/ml, 4-fold increase). The results show continuous increase of retinoic acids, which have to be considered as potential teratogens, after administration of vitamin A. The plasma concentration of retinol itself did not change, whereas only short-term increases were observed for retinol esters.

Distribution, teratogenicity, and embryonic delivered dose of retinoid Ro 23-9223.

Ro 23-9223 is a highly lipophilic aromatic retinoid with antiproliferative and sebum supressive effects in preclinical disease models of acne. To investigate the relation between Ro 23-9223 developmental toxicity, drug distribution, and transplacental transfer, groups of pregnant hamsters were given oral doses of 50-500 mg/kg Ro 23-9223 on days 8 and 9 of gestation. The teratogenic phenotype induced at doses greater than 125 mg/kg per day was similar to that found after exposure to doses of 13-cis-retinoic acid (isotretinoin, Accutane) greater than 37.5 mg/kg per day. Oral bioavailability of Ro 23-9223 was very low compared to 13-cis-retinoic acid. The highest concentrations of Ro 23-9223 were found in maternal liver, lung, adipose tissue, cardiac muscle, and placenta, whereas only little of the compound crossed the blood-brain barrier. Based on embryo AUC, Ro 23-9223 had a 30- to 50-fold greater embryo:maternal concentration ratio than 13-cis-retinoic acid plus its bioactive metabolites following similar doses of the two retinoids. In preclinical pharmacology studies, oral doses of Ro 23-9223 (5 mg/kg per day) and 13-cis-retinoic acid (10 mg/kg per day) produced comparable gland size reductions in the hamster ear sebaceous gland reduction assay. Under these conditions, Ro 23-9223 plasma AUC was 40 times smaller than that of 13-cis-retinoic acid plus its bioactive metabolites. Assuming that the near linear dose-exposure relationship of Ro 23-9223 extends beyond the dose range of this study, embryo AUCs of Ro 23-9223 and 13-cis-retinoic acid (plus metabolites) would be near identical following pharmacologically equivalent doses. A comparison of embryo retinoid AUCs suggests a 4-fold lower teratogenic potency of Ro 23-9223 compared to with 13-cis-retinoic acid. Despite high embryo levels in hamsters, the data suggest an improved therapeutic index for Ro 23-9223 compared with 13-cis-retinoic acid in a preclinical acne disease model.

Human plasma all-trans-, 13-cis- and 13-cis-4-oxoretinoic acid profiles during subchronic vitamin A supplementation: comparison to retinol and retinyl ester plasma levels.

Plasma concentrations of retinyl esters, retinol, retinol-binding protein and the polar retinol metabolites all-trans-retinoic acid, 13-cis-retinoic acid, all-trans-4-oxoretinoic acid and 13-cis-4-oxoretinoic acid were measured for six male volunteers who received 0.46 mg retinyl palmitate per kilogram body weight as oily drops (equivalent to 0.25 mg retinol per kilogram body weight) once daily over a 20-d period. Retinol and retinol-binding protein levels remained virtually constant throughout the study. Following absorption of vitamin A, retinyl esters as well as all-trans-retinoic acid and 13-cis-retinoic acid were transiently increased in plasma. 13-cis-4-Oxoretinoic acid increased gradually to a steady state level present on d 10 or 20. All-trans-4-oxoretinoic acid was not detected in plasma of the volunteers, with the exception of one on d 10 of the study. Plasma pharmacokinetic profiles of retinyl esters and polar metabolites of retinol displayed great interindividual differences (peak concentrations, time to peak, area-under-the-concentration-time curve values) among the volunteers. Because of the relatively high and consistent steady state concentrations of plasma 13-cis-4-oxoretinoic acid, we suggest that this compound be further investigated as a biochemical marker of vitamin A uptake in humans.

Characterization of oxidized and glucuronidated metabolites of retinol in monkey plasma by thermospray liquid chromatography/mass spectrometry.

Eight metabolites of retinol were isolated by high-performance liquid chromatography (HPLC) from the plasma of the non-human primate Macaca fascicularis after acute exposure to 150,000 IU of vitamin A per kilogram body weight. After enrichment and further chromatographic purification, the metabolites were reinjected individually into a second HPLC system which was connected on-line by a thermospray interface to a mass spectrometer operated in the positive ionization mode. Six retinoids were identified by (i) a comparison of their retention times with those of appropriate reference compounds in the two chromatographic systems and (ii) by comparison of their mass spectra with those of reference compounds. These retinoids were: 13-cis-4-oxoretinoic acid, all-trans-4-oxoretinoic acid, 13-cis-retinoic acid, all-trans-retinoic acid, all-trans-retinoyl beta-glucuronide and all-trans-retinyl beta-glucuronide. One further metabolite could be identified for the first time as all-trans-4-oxoretinoyl beta-glucuronide by its mass spectrum and, after treatment of the unknown metabolite with beta-glucuronidase, by its hydrolysis product all-trans-4-oxoretinoic acid. The molecular structure of one metabolite could not be elucidated. A major metabolic pathway of high-dose vitamin A in the non-human primate is apparently the oxidation of the primary alcohol group of retinol resulting in the formation of all-trans-retinoic acid. Subsequently, a broad spectrum of various metabolites of all-trans-retinoic acid, including beta-glucuronides and retinoids with a 13-cis configuration, appear in the plasma.

Suppression of collagenase gene expression by all-trans and 9-cis retinoic acid is ligand dependent and requires both RARs and RXRs.

Retinoic acids (RA) are active metabolites of vitamin A which affect the expression of many genes involved in embryonic development, cell differentiation, and homeostasis. One important target gene for RA is matrix metalloproteinase (MMP-1, collagenase), the only enzyme active at neutral pH that can degrade interstitial collagen, a major component of extracellular matrix. Using a cell line of normal rabbit synovial fibroblasts, HIG82 cells, as a model, we report that both all-trans- and 9-cis-RA inhibit collagenase synthesis. This inhibition occurs at a transcriptional level and is ligand-dependent. Constitutive levels of retinoic acid receptor (RAR) mRNA levels are low, but are increased by all-trans and by 9-cis RA. In contrast, constitutive levels of retinoid X receptor (RXR) mRNA are higher and are not affected by RA. To measure DNA/protein interactions, we used a gel mobility shift assay with oligonucleotides containing either an AP-1 site or a 40 bp region between -182/-141, nuclear extracts from RT-treated cells, and antibodies to RARs and RXRs. We found that both RARs and RXRs interact with these regions of the collagenase promoter, perhaps as part of a complex with other proteins. Our results suggest that heterodimers between RARs and RXRs mediate suppression of the collagenase gene by RA, and that RAR is a limiting factor in this negative regulation.

Pharmacokinetics of 13-cis-, all-trans-, 13-cis-4-oxo-, and all-trans-4-oxo retinoic acid after intravenous administration in the cynomolgus monkey.

The intravenous pharmacokinetics of 13-cis-, all-trans-, 13-cis-4-oxo, and all-trans-4-oxo retinoic acid (RA) were determined in nonpregnant female cynomolgus monkeys. All-trans- and 13-cis-RA were injected at two doses (0.25 or 0.0125 mg/kg) and all-trans-4-oxo RA and 13-cis-4-oxo RA at 0.25 mg/kg. Total body clearance, volume of distribution, and volume of distribution at steady state of all-trans-RA were dose-dependent with greater values at the lower dose. Elimination half-life was longer for the cis-compounds and not dose-dependent (N = 1 for 13-cis-4-oxo RA, N = 3 for other compounds, harmonic mean +/- pseudostandard deviation, min): 13-cis-4-oxo RA (837) > or = 13-cis-RA (301 +/- 204) > all-trans-RA (38 +/- 3) > all-trans-4-oxo RA (11 +/- 2). Secondary plasma peaks were noted only after administration of 13-cis-4-oxo RA. The low area under the time concentration curves for observable metabolites after intravenous injection of the oxidated compounds suggests further metabolism plays a minimal role in the elimination of these compounds from the monkey. Plasma-time concentration curves were fitted to multicompartmental models and suggested < 30% of each compound was available in the central compartment for elimination in the postdistribution phase. A comparison of the kinetics of the isomers indicated oxidation of all-trans-RA to all-trans-4-oxo RA increased mean total body clearance values 4-fold.(ABSTRACT TRUNCATED AT 250 WORDS)