Search

The teratogenicity of the chemotherapeutic drug thalidomide is species-specific and affects humans, non-human primates, and rabbits. The primary oxidation of thalidomide in previously investigated rodents predominantly resulted in the formation of deactivated 5'-hydroxythalidomide. In the current study, similar in vivo biotransformations to 5-hydroxythalidomide and 5'-hydroxythalidomide were confirmed by the analysis of blood plasma from male rabbits, a thalidomide-sensitive species, after oral administration of thalidomide (2.0 mg/kg). Similar levels of thalidomide in seminal plasma and in blood plasma were detected using liquid chromatography-tandem mass spectrometry at 4 hr and 7 hr after oral doses in male rabbits. Seminal plasma concentrations of 5-hydroxythalidomide and 5'-hydroxythalidomide were also seen in male rabbits in a roughly similar time-dependent manner to those in the blood plasma after oral doses of thalidomide (2.0 mg/kg). Furthermore, the values generated by a simplified physiologically based pharmacokinetic rabbit model were in agreement with the measured in vivo blood plasma data under metabolic ratios of 0.01 for the hepatic intrinsic clearance of thalidomide to both unconjugated 5-hydroxythalidomide and 5'-hydroxythalidomide. These results suggest that metabolic activation of thalidomide may be dependent on rabbit liver enzymes just it was for cytochrome P450 enzymes in humanized-liver mice; in contrast, rodent livers predominantly mediate biotransformation of thalidomide to 5'-hydroxythalidomide. A developmental toxicity test system with experimental animals that involves intravaginal exposures to the chemotherapeutic drug thalidomide via semen should be considered in the future.

3-(6-Methylpyridine-3-yl-sulfanyl)-6-(4H-[1,2,4]triazole-3-yl-sulfanyl)-N-(1,3-thiazole-2-yl)-2-pyridine carboxamide (Cpd-D) is a novel glucokinase activator that is being developed for the treatment of type 2 diabetes. Large interindividual variations were observed in the pharmacokinetics of Cpd-D in male Sprague-Dawley (SD) rats, which were subsequently divided into two phenotypes; >6-fold longer terminal-phase half-life and ∼10-fold larger AUC0-∞ values were observed in slow metabolizers (SM) than in fast metabolizers (FM) after the oral administration of Cpd-D. The thiohydantoic acid analog (M2) was the predominant metabolite detected in the urine, bile, and plasma after the oral administration of [(14)C]Cpd-D to the FM phenotypes of bile-duct cannulated SD rats. The liver microsomes prepared from FM phenotyped rats extensively formed M2 with the highest affinity (Km = 0.09 μM) and largest Vmax/Km value in primary metabolism, whereas those from SM phenotypes had little capacity to form M2. Of the rat cytochrome P450 isoforms tested, the formation of M2 was only catalyzed by recombinant CYP2D1. Sequence substitutions (418A/421C and 418G/421T) were detected in the CYP2D1 gene and were designated F and S alleles, respectively. The genotype-phenotype correlation analysis indicated that two S alleles were homozygous (S/S) in the SM phenotypes, whereas the FM phenotypes were either homozygous for the F-alleles (F/F) or heterozygous (F/S). These results indicated that the CYP2D1 polymorphism caused by nucleotide substitutions (418A/421C versus 418G/421T) was responsible for interindividual variations leading to the polymorphism in the major metabolism and pharmacokinetics of Cpd-D in male SD rats.

The optimization of our lead GK activator 2a to 3-[(1S)-2-hydroxy-1-methylethoxy]-5-[4-(methylsulfonyl)phenoxy]-N-1,3-thiazol-2-ylbenzamide (6g), a potent GK activator with good oral availability, is described, including to uncouple the relationship between potency and hydrophobicity. Following oral administration, this compound exhibited robust glucose lowering in diabetic model rodents.

Identification and synthesis of novel 3-alkoxy-5-phenoxy-N-thiazolyl benzamides as glucokinase activators are described. Removal of an aniline structure of the prototype lead (2a) and incorporation of an alkoxy or phenoxy substituent led to the identification of 3-Isopropoxy-5-[4-(methylsulfonyl)phenoxy]-N-(4-methyl-1,3-thiazol-2-yl)benzamide (27e) as a novel, potent, and orally bioavailable GK activator. Rat oral glucose tolerance test indicated that 27e exhibited a glucose-lowering effect after 10 mg/kg oral administration.

Little information is available on the direction-dependency of shear behavior in mandibular condylar cartilage. Therefore, we tested the hypothesis that such a dependency of the dynamic shear properties is present in mandibular condylar cartilage. From each of 17 condyles, two cartilage-bone plugs were dissected and tested in a simple shear sandwich configuration under a compressive strain of 10%. Sinusoidal shear strain (frequency range: 0.01-10Hz) was applied in the medio-lateral or antero-posterior direction with an amplitude of 1.0%, 2.0%, and 3.0%. The magnitudes of the dynamic shear moduli, as calculated from the resulting shear stress, were found to increase with applied frequency and the shear strain amplitude. The values of vertical bar G*vertical bar, G' and G" for a medio-laterally applied shear were about 20-33% of those in the antero-posterior shear, although the loss tangent (elasticity/viscosity ratio) was almost the same. In conclusion, the present results clearly show the direction-dependent characteristic of the mandibular condylar cartilage in dynamic shear.

The osteoinductive activity induced by recombinant human BMP-2 (rhBMP-2) blunts proportionately as the recipient ages. In order to compensate for this bluntness administration of fibroblast growth factor-2 (FGF-2) has been considered. The aim of this study was to determine whether FGF-2 administration augments osteoinductive activity caused by rhBMP-2 and to evaluate the effect of aging on bone formation induced by coadministration of rhBMP-2 and FGF-2. Sixty-four Wistar strain male rats of 8-week-old (prepubertal) and 16-week-old (postpubertal) received bone defects bilaterally in the parietal bone and the defects were filled by a polylactic acid polyglycolic acid copolymer/gelatin sponge (PGS) impregnated with rhBMP-2 plus 0 ng, 25 ng, and 250 ng FGF-2 (n=10 in each). At 2 weeks after grafting, the new bone volume seemed to be larger in the rhBMP-2+FGF-2 groups than in the rhBMP-2 alone group. At 4 weeks, the new bone formation was linked to the adjacent original bone. In the prepubertal rats, all newly formed bone was similarly calcified. In the postpubertal rats, only the rhBMP-2+25 ng FGF-2 group showed this higher degree of calcification. At 2 weeks, alkaline phosphatase (ALP) activity in the rhBMP-2+25 ng FGF-2 group was significantly (p

A novel series of (2R)-2-[(1R)-3, 3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamides was designed and synthesized based on the structure and biological profiles of an active metabolite 2 of our prototype muscarinic M(3) receptor selective antagonist 1, to develop a potent, long-acting, orally active M(3) antagonist for the treatment of urinary tract disorders, irritable bowel syndrome, and respiratory disorders. Investigation of (2R)-2-[(1R)-3, 3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamides containing a phenyl or heterocyclic ring as the piperidinyl side chain in place of the 4-methyl-3-pentenyl moiety of 15a revealed that this acid moiety was a versatile template for improving the selectivity for M(3) over M(2) receptors in comparison with the corresponding cyclopentylphenylacetic acid group. However, since the in vitro metabolic stability of these analogues was insufficient compared with that of 2, further derivatization was performed by introducing an appropriate hydrophilic group into the phenyl or 2-pyridyl ring. Thus, the 1-(6-aminopyridin-2-ylmethyl)piperidine analogue 15y exhibiting 190-fold selectivity for M(3) receptors (K(i) = 2.8 nM) over M(2) receptors (K(i) = 530 nM) in a human binding assay and good in vitro metabolic stability in dog and human hepatic microsomes was identified. This compound has excellent oral activity at 4 h after oral dosing (1 mg/kg), inhibiting methacholine-induced bronchoconstriction in dogs, and may be useful in clinical situations in which M(3) over M(2) selectivity is desirable.

In the course of developing a metabolically stable M3 receptor antagonist from the prototype antagonist, J-104129 (1), introduction of certain substituents into the cyclopentane ring of 1 was found to be effective not only in improving metabolic stability but also in greatly enhancing the subtype selectivity. Among the cyclopentane analogues, sulfonamide derivatives (10f) and (10g) displayed 160- and 310-fold selectivity for M3 over M2 receptors, and both were significantly more selective than the prototype antagonist (120-fold). Subsequent derivatization of the sulfonamide series led to the highly selective M3 receptor antagonists (10h, 10i and 10j) with >490-fold selectivity for M3 over M2 receptors. Among them, p-nitrophenylsulfonamide (J-107320, 10h) exhibited 1100-fold selectivity for M3 receptors (Ki = 2.5 nM) over M2 receptors (Ki = 2800 nM) in the human muscarinic receptor binding assay using [3H]-NMS as a radio ligand.

Dorzolamide hydrochloride (MK-507), (-)-(4S, 6S)-4-ethylamino-5, 6-dihydro-6-methyl-4H-thieno-[2, 3-b]-thiopyran-2-sulfonamide-7, 7-dioxide monohydrochloride, is a new topical carbonic anhydrase inhibitor. The binding of dorzolamide and its N-deethylated metabolite (L-706, 803) to rat erythrocytes was investigated, and the pharmacokinetics of dorzolamide in rats was studied after a single intravenous administration.1. Dorzolamide was incorporated into rat erythrocytes rapidly, while the uptake of L-706, 803 was slower.2. There were two types of binding site for dorzolamide and L-706, 803 in rat erythrocytes. For both dorzolamide and L-706, 803, the maximum binding capacity was about 60 μM for the high affinity isozyme and 30 μM for the low affinity isozyme.3. The Kd values of dorzolamide and L-706, 803 for low affinity binding were 0.387 and 0.497 μM, respectively. The Kd values of dorzolamide and L-706, 803 for high affinity binding were about 1/100 and 1/250 of those for low affinity binding, respectively.4. After administration of dorzolamide hydrochloride to rats at the dose of 0.5 mg/kg, dorzolamide and L-706, 803 were not detected in plasma. At the dose of 5 mg/kg, the plasma half-lives of dorzolamide and L-706, 803 were 1.0 and 2.6 hr, respectively.5. At the dose of 0.5 mg/kg, the half-lives of dorzolamide and L-706, 803 in blood were 157 and 116 hr, respectively, and decreased to respective values of 101 and 99 hr after administration of 5 mg/kg.6. After administration of dorzolamide hydrochloride at the dose of 0.5 mg/ kg, the blood AUC values of dorzolamide and L-706, 803 were 1093 and 115 μg hr/ml, respectively. The AUC value of dorzolamide at the dose of 5 mg/kg decreased by 50% and that of L-706, 803 increased about five-fold.7. The Vdss and CLtot of dorzolamide were 99.9 ml/kg and 0.46 ml/hr/kg after administration of 0.5 mg/kg and increased 15 and 25-fold after 5 mg/kg, respectively.

The absorption, distribution, metabolism and excretion of [14C]dorzolamide hydrochloride (MK-507) were studied in rats after single administration. In vitro plasma protein binding was also investigated.1. Following intravenous administration of [14C]dorzolamide hydrochloride to male rats at doses ranging from 0.1 to 5 mg/kg, blood AUC values increased proportionally with doses up to 0.5 mg/kg, but no increase in the values was observed for the dose range of 1 to 5 mg/kg. Most of the radioactivity in blood was present in erythrocytes. The elimination of radioactivity from the blood was very slow and the estimated t1/2 was 10.5-11.3 days.2. No sex differences were observed in blood concentration profiles regardless route of administration, oral or intravenous. After oral administration, almost all [14C]dorzolamide was absorbed.3. After intravenous administration at the dose of 0.5 mg/kg, most of the radioactivity was distributed in blood. At 30 min after dosing, the highest radioactivity was found in the kidney, followed by lung, spleen, bone marrow, stomach, liver, caecum and large intestine. The concentration-time profiles of most tissues were similar to that of blood.4. Within 31 days after intravenous administration at the dose of 0.5 mg/kg, the excretion of radioactivity accounted for 74.7% in urine and 11.8% in feces. Within 24 hr after oral administration at the dose of 0.5 and 5 mg/kg, 24.7 and 73.8% of administered radioactivity were excreted in urine, respectively.5. N-deethylated dorzolamide was found in the blood, urine and tissues. The ratio of the radioactive N-deethylated metabolite to the total radioactivity in blood or in tissues after administration at the dose of 5 mg/kg was larger than those after dosing at the dose of 0.5 mg/kg.6. The in vitro binding of dorzolamide and N-deethylated dorzolamide to plasma proteins accounted for less than 30% in all species studied, and these compounds were mainly bound to albumin.

Glucokinase activators (GKAs) are currently under investigation as potential antidiabetic agents by many pharmaceutical companies. Most of GKAs reported previously possess N-aminothiazol-2-yl amide moiety in their structures because the aminothiazole moiety interacts with glucokinase (GK) and shows strong GK activation. During the development of N-aminothiazol-2-yl amide derivatives, we identified a bioactivation and metabolic liability of 2-aminothizole substructure of GKA 3 by assessing covalent binding, metabolites in liver microsomes and glutathione (GSH) trap assay.

Background Osteoblasts and adipocytes are derived from a common mesenchymal progenitor and an inverse relationship between expression of the two lineages is seen with certain experimental manipulations and in certain diseases, i.e., osteoporosis, but the cellular pathway(s) and developmental stages underlying the inverse relationship is still under active investigation. To determine which precursor mesenchymal cell types can differentiate into adipocytes, we compared the effects of BRL-49653 (BRL), a selective ligand for peroxisome proliferators-activated receptor (PPAR)γ, a master transcription factor of adipogenesis, on osteo/adipogeneis in two different osteoblast culture models: the rat bone marrow (RBM) versus the fetal rat calvaria (RC) cell system. Results BRL increased the number of adipocytes and corresponding marker expression, such as lipoprotein lipase, fatty acid-binding protein (aP2), and adipsin, in both culture models, but affected osteoblastogenesis only in RBM cultures, where a reciprocal decrease in bone nodule formation and osteoblast markers, e.g., osteopontin, alkaline phosphatase (ALP), bone sialoprotein, and osteocalcin was seen, and not in RC cell cultures. Even though adipocytes were histologically undetectable in RC cultures not treated with BRL, RC cells expressed PPAR and CCAAT/enhancer binding protein (C/EBP) mRNAs throughout osteoblast development and their expression was increased by BRL. Some single cell-derived BRL-treated osteogenic RC colonies were stained not only with ALP/von Kossa but also with oil red O and co-expressed the mature adipocyte marker adipsin and the mature osteoblast marker OCN, as well as PPAR and C/EBP mRNAs. Conclusion The data show that there are clear differences in the capacity of BRL to alter the fate choices of precursor cells in stromal (RBM) versus calvarial (RC) cell populations and that recruitment of adipocytes can occur from multiple precursor cell pools (committed preadipocyte pool, multi-/bipotential osteo-adipoprogenitor pool and conversion of osteoprogenitor cells or osteoblasts into adipocytes (transdifferentiation or plasticity)). They also show that mechanisms beyond activation of PPARγ by its ligand are required for changing the fate of committed osteoprogenitor cells and/or osteoblasts into adipocytes.

The correction of a severe maxillary protrusion in an adult by distal movement of the maxillary molars has been one of the most difficult biomechanical problems in orthodontics. This article reports on the treatment of an adult case of severe maxillary protrusion and a large overjet treated with a skeletal anchorage system. A female patient, age 22 years and 3 months, complained of the difficulty of lip closure due to severe maxillary protrusion with a gummy smile. Overjet and overbite were +7.6 mm and −0.9 mm, respectively. She had a history of orthodontic treatment in which her maxillary first premolars were extracted. In order to conduct distal movement of the maxillary molars, anchor plates were placed in the zygomatic process. After achieving a Class I molar relationship, retraction and intrusion of the maxillary incisors were performed. After a 2-year treatment, an acceptable occlusion was achieved with a Class I molar relationship. Her convex facial profile with upper lip protrusion was considerably improved, and the lips showed less tension in lip closure. After a 2-year retention period, an acceptable occlusion was maintained without recurrence of maxillary protrusion, indicating a stability of the occlusion. The result of this treatment indicated that skeletal anchorage is of great importance as a remedy for achieving intrusion and retraction of the maxillary incisors in cases of severe maxillary protrusion with a patient who had previous orthodontic treatment.

This study reports the treatment of an adolescent patient with dilacerated maxillary incisor. She complained of severe crowding with a high-positioned left upper canine. Her left central incisor had been impacted and moved to proper position at the age of eight years, resulting in a severe root dilaceration. To avoid any progression of root dilacerations and resorption in the maxillary incisor, maxillary lateral expansion and molar distalization plus multibracket appliance were selected as the best nonextraction treatment plan. The maxillary expansion and molar distalization should provide adequate space for the correction of the severe crowding, and treatment with a multibracket appliance was initiated. After a 17-month treatment with a multibracket appliance, an acceptable occlusion was achieved with a Class I molar relationship. An acceptable occlusion was maintained without recurrence of the crowding and impairment of the dilacerated root in the maxillary incisor during three years of retention. It is emphasized that careful planning is required to avoid any progression of the root dilaceration and resorption through orthodontic treatment. A shortening of the period of applying orthodontic force on the dilacerated incisor and avoidance of tooth extraction will minimize the risk factors.

Control of the height of posterior dentoalveolar regions is of great importance for the correction of skeletal open bite. Traditionally, second premolar extraction facilitates the closure of open bite by inducing a counterclockwise mandibular rotation without molar intrusion. This article reports treatment for a 24-year six-month-old female patient with an open bite and large anterior facial height. She complained of occlusal disturbances and difficulty of lip closure because of the open bite. Overjet and overbite were +3.0 mm and -3.0 mm, respectively. To correct open bite and crowding, the bilateral extraction of the maxillary and mandibular second premolars plus multibracket appliances for mesial movement of the molars was selected as the treatment plan. After a two-year treatment, an acceptable occlusion was achieved, the lower anterior facial height was decreased, and the lips showed less tension in a lip closure. An acceptable occlusion was maintained without recurrence of the open bite during a three-year retention period, indicating a long-term stability of the occlusion. The results of this treatment indicated that the correction of open bite with no or less molar intrusion or incisor extrusion is of great importance for achieving stable occlusion and avoiding the relapse of open bite.

Optimization of the amine part of our original muscarinic M(3) receptor antagonist 1 was performed to identify M(3) receptor antagonists that are superior to 1. Compounds carrying a variety of diamine moieties without hydrophobic substituent on the nitrogen atom were screened against the binding affinity for the M(3) receptor and the selectivity for M(3) over the M(1) and M(2) receptors. This process led to a 4-aminopiperidinamide (2l) with a K(i) value of 5.1 nM and with a selectivity of the M(3) receptor that was 46-fold greater than that of the M(2) receptor. Further derivatization of 2l by inserting a spacer group or by incorporating alkyl group(s) into the amine part resulted in the identification of an 4-(aminoethyl)piperidinamide 2l-b with a K(i) value of 3.7 nM for the M(3) receptor and a selectivity for the M(3) receptor that was 170-fold greater than that of the M(2) receptor.

Alterations in the pattern of gene expression were studied during differentiation of the human embryonal carcinoma (EC) cell line NEC14. NEC14 cells can be induced to differentiate by the addition of 10-2 M N,N′-hexamethylene-bis-acetamide (HMBA). The efficiency of DNA transfection of undifferentiated and differentiated NEC14 cells was compared by measuring the activities of endogenous and exogenously introduced promoters for the beta-actin gene and heat shock protein 70 gene. The results indicated that the efficiency was not significantly different in cells of these two states. Under the conditions used, all the viral enhancer-promoters tested showed very little or no activity in undifferentiated cells, but activities of SV40, BKV, adenovirus and RSV enhancers were greatly increased after differentiation. Activities of these viral enhancers in differentiated cells were completely repressed by cotransfection with the adenovirus E1A gene. An E1 A-inducible promoter of the adenovirus E2 gene showed stronger activity in differentiated than in undifferentiated cells, and was not activated efficiently by cotransfection with the E1 A gene in either undifferentiated or differentiated cells. These results indicate that factor(s) regulating activities of various enhancer-promoters in NEC14 cells is or are different from E1A-like factor(s) present in mouse EC F9 cells.