Randomised comparison of initial triple DMARD therapy with methotrexate monotherapy in combination with low-dose glucocorticoid bridging therapy; 1-year data of the tREACH trial.

OBJECTIVES: To compare 1-year clinical efficacy of (1) initial triple disease-modifying antirheumatic drug therapy (iTDT) with initial methotrexate (MTX) monotherapy (iMM) and (2) different glucocorticoid (GC) bridging therapies: oral versus a single intramuscular injection in early rheumatoid arthritis. METHODS: In a single-blinded randomised clinical trial patients were randomised into three arms: (A) iTDT (methotrexate+sulfasalazine+hydroxychloroquine) with GCs intramuscularly; (B) iTDT with an oral GC tapering scheme and (C) MTX with oral GCs similar to B. Primary outcomes were (1) area under the curve (AUC) of Health Assessment Questionnaire (HAQ) and Disease Activity Score (DAS) and (2) the proportion of patients with radiographic progression. RESULTS: 281 patients were randomly assigned to arms A (n=91), B (n=93) or C (n=97). The AUC DAS and HAQ were respectively -2.39 (95% CI -4.77 to -0.00) and -1.67 (95% CI -3.35 to 0.02) lower in patients receiving iTDT than in those receiving iMM. After 3 months, treatment failure occurred less often in the iTDT group, resulting in 40% fewer treatment intensifications. The difference in treatment intensifications between the arms required to maintain the predefined treatment goal remained over time. No differences were seen between the two GC bridging therapies. Respectively 21%, 24% and 23% of patients in arms A, B and C had radiographic progression after 1 year. Patients receiving iTDT had more adjustments of their medication owing to adverse events than those receiving iMM. CONCLUSIONS: Treatment goals are attained more quickly and maintained with fewer treatment intensifications with iTDT than with iMM. However, no difference in radiographic progression is seen. Both GC bridging therapies are equally effective and, therefore, both can be used. TRIAL REGISTRATION NUMBER: ISRCTN26791028.

Computer-assisted videokeratography to measure changes in astigmatism induced by sutureless cataract surgery.

PURPOSE: To compare the visual outcome, change in surgically induced astigmatism, and corneal thickness after sutureless cataract surgery through either a scleral tunnel or clear corneal incision. SETTING: Department of Ophthalmology, Kangnam St. Mary's Hospital, Catholic University Medical College, Seoul, Korea. METHODS: This retrospective study evaluated 79 eyes of 64 patients who had cataract surgery using a 6.0 mm scleral tunnel incision (Group 1, n = 20 eyes), 3.1 mm clear corneal incision at the 10 o'clock position (Group 2, n = 35 eyes), or 3.1 mm clear corneal incision at the 10 o'clock position (Group 3, n = 24 eyes). Changes in surgically induced astigmatism were analyzed using computer-assisted videokeratography (CVK) 1 day, 8 weeks, and 6 months postoperatively. RESULTS: Eleven eyes (55.0%) in Group 1, 15 (42.8%) in Group 2, and 11 (48.5%) in Group 3 had an uncorrected visual acuity of 20/40 or better 1 day postoperatively. The CVK measurements showed significantly more flattening at radial distances of 0.75, 1.50, and 2.50 mm along the 90 degree semimeridian in Group 2 than in Group 1 (P < .05) 1 day after surgery; in Group 3, flattening along the incisional semimeridian fell between the amounts in Groups 1 and 2. At 8 weeks, the amount of flattening decreased in all groups, and the differences between groups were not statistically significantly different (P > .05). In the CVK pattern, corneal flattening along the incisional meridian was narrower and longer in Groups 2 and 3 than in Group 1. CONCLUSION: Localized flattening along the incisional meridian was prominent temporally after clear corneal incision surgery. However, there was no difference in early visual rehabilitation between the clear corneal and scleral tunnel incision groups.

In vitro stability and intestinal absorption characteristics of hexapeptide endothelin receptor antagonists.

Endothelins are potent vasoconstrictor peptides which have a wide range of tissue distribution and three receptor subtypes (ET(A), ET(B) and ET(C)). Among the linear hexapeptide ET(A)/ET(B) receptor antagonists, PD 145065 (Ac-D-Bhg-L-Leu-L-Asp-L-Ile-L-Ile-L-Trp, Bhg = (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-yl)-Gly) and PD 156252 (Ac-D-Bhg-L-Leu-L-Asp-L-Ile-(N-methyl)-L-Ile-L-Trp) were selected to evaluate the metabolic stability and intestinal absorption in the absence and/or in the presence of protease inhibitors. In vitro stability of both compounds was investigated in fresh plasma, lumenal perfusate, intestinal and liver homogenates. PD 156252 was more stable than PD 145065 in intestinal tissue homogenate (63.4% vs. 20.5% remaining) and liver homogenate (74.4% vs. 35.5% remaining), while both compounds showed relatively good stability in the fresh plasma (94.5% vs. 86.7% remaining) and lumenal perfusate (85.8% vs. 72.3% remaining). The effect of protease inhibitors on the degradation of PD 145065 and PD 156252 was also investigated. Amastatin, thiorphan, chymostatin and the mixture of these three inhibitors were effective in reducing the degradation of both compounds. The pharmacokinetic parameters of PD 156252, calculated by using a non-compartmental model, were 6.95 min (terminal half-life), 191 mL (Vss), and 25.5 mL/min (Cl(tot)) after intravenous administration in rats. The intestinal absorption of PD 156252 in rats was evaluated in the absence and/or in the presence of protease inhibitors. The results indicate that the major elimination pathway of PD 156252 appears to be the biliary excretion and protease inhibitors increase the intestinal absorption of PD 156252 through increasing metabolic stability.

CHO/hPEPT1 cells overexpressing the human peptide transporter (hPEPT1) as an alternative in vitro model for peptidomimetic drugs.

The present study characterized Chinese hamster ovary cells overexpressing a human intestinal peptide transporter, CHO/hPEPT1 cells, as an in vitro model for peptidomimetic drugs. The kinetic parameters of Gly-Sar uptake were determined in three different cell culture systems such as untransfected CHO cells (CHO-K1), transfected CHO cells (CHO/hPEPT1) and Caco-2 cells. Vmax in CHO/hPEPT1 cells was approximately 3-fold higher than those in Caco-2 cells and CHO-K1 cells, while Km values were similar in all cases. The uptake of beta-lactam antibiotics in CHO/hPEPT1 cells was three to twelve fold higher than that in CHO-K1 cells, indicating that CHO/hPEPT1 cells significantly enhanced the peptide transport activity. However, amino acid drugs also exhibited high cellular uptake in both CHO-K1 and CHO/hPEPT1 cells due to the high background level of amino acid transporters. Thus, cellular uptake study in CHO/hPEPT1 cells is not sensitive enough to distinguish the peptidyl drugs from amino acid drugs. The potential of CHO/hPEPT1 cells as an in vitro model for peptidomimetic drugs was also examined through the inhibition study on Gly-Sar uptake. Peptidomimetic drugs such as beta-lactam antibiotics and enalapril significantly inhibited Gly-Sar uptake whereas the nonpeptidyl compounds, L-dopa and alpha-methyldopa, did not compete with Gly-Sar for cellular uptake within the therapeutic concentrations. In conclusion, the present study demonstrates the further characterization of CHO/hPEPT1 cells as an uptake model as well as inhibition study and suggests their utility as an alternative in vitro model for drug candidates targeting the hPEPT1 transporter.

Targeted prodrug design to optimize drug delivery.

Classical prodrug design often represents a nonspecific chemical approach to mask undesirable drug properties such as limited bioavailability, lack of site specificity, and chemical instability. On the other hand, targeted prodrug design represents a new strategy for directed and efficient drug delivery. Particularly, targeting the prodrugs to a specific enzyme or a specific membrane transporter, or both, has potential as a selective drug delivery system in cancer chemotherapy or as an efficient oral drug delivery system. Site-selective targeting with prodrugs can be further enhanced by the simultaneous use of gene delivery to express the requisite enzymes or transporters. This review highlights evolving strategies in targeted prodrug design, including antibody-directed enzyme prodrug therapy, gene-directed enzyme prodrug therapy, and peptide transporter-associated prodrug therapy.

Role of intraepithelial lymphocytes in mucosal immune responses of mice experimentally infected with Cryptosporidium parvum.

In order to investigate the role of intestinal intraepithelial lymphocytes (IELs) in host defense against Cryptosporidium parvum infection, conventionally bred immunocompetent (ImCT) ICR mice and immunosuppressed (ImSP) littermates were infected orally with 10(6) C. parvum oocysts. Then fecal oocyst excretion, the number and location of IELs, and their T lymphocyte subsets were observed on days 4, 7, 10, 13, 16, and 20 postinfection (PI). Uninfected ImCT and ImSP mice were used as controls. The starting point of oocyst excretion was day 4 PI in both ImCT- and ImSP-infected mice. The highest oocyst excretion occurred on day 7 PI in both groups, though the number of oocysts excreted was 3 times greater in ImSP than in ImCT mice. In ImCT mice, IELs greatly increased in number on days 16 and 20 PI (P < 0.05), but the increase was minimal in ImSP mice. IELs changed their location from the basal area to intermediate and apical areas of villous epithelial cells during the early stage of infection. In ImCT-infected mice, IEL phenotypes also changed; whereas CD4+ cells increased temporarily on day 7 PI (P < 0.05), CD8+ cells increased significantly on days 16 and 20 PI (P < 0.05). The results strongly suggest that IELs play a significant role in host defense against C. parvum infection, with helper T cells initiating control of the infection and cytotoxic T cells eliminating the parasites.

Cellular uptake mechanism of amino acid ester prodrugs in Caco-2/hPEPT1 cells overexpressing a human peptide transporter.

PURPOSE: This study characterized the cellular uptake mechanism and hydrolysis of the amino acid ester prodrugs of nucleoside antiviral drugs in the transiently transfected Caco-2 cells overexpressing a human intestinal peptide transporter, hPEPT1 (Caco-2/hPEPT1 cells). METHODS: Amino acid ester prodrugs of acyclovir and AZT were synthesized and their apical membrane permeability and hydrolysis were evaluated in Caco-2/hPEPT1 cells. The cellular uptake mechanism of prodrugs was investigated through the competitive inhibition study in Caco-2/hPEPT1 cells. RESULTS: L-Valyl ester of acyclovir (L-Val-ACV) was approximately ten fold more permeable across the apical membrane than acyclovir and four times more permeable than D-valyl ester of acyclovir (D-Val-ACV). Correspondingly, L-valyl ester of AZT (L- Val-AZT) exhibited three fold higher cellular uptake than AZT. Therefore, amino acid ester prodrugs significantly increased the cellular uptake of the parent drugs and exhibited the D,L-stereoselectivity. Furthermore, prodrugs were rapidly hydrolyzed to the parent drugs by the intracellular hydrolysis, following the apical membrane transport. In the inhibition studies, cephalexin and small dipeptides strongly inhibited the cellular uptake of L-Val-ACV while L-valine had no effect, indicating that the peptide transporter is primarily responsible for the apical membrane transport of L-Val-ACV. In addition, the cellular uptake of L-Val-ACV was five times higher in Caco-2/hPEPT1 cells than the uptake in the untransfected Caco-2 cells, implying the cellular uptake of L-Val-ACV was related to the enhancement of the peptide transport activity in Caco-2/hPEPT1 cells. CONCLUSIONS: Caco-2/hPEPT1 system is an efficient in vitro model for the uptake study of peptidyl derivatives. Amino acid ester prodrugs significantly improved the cellular uptake of the parent drugs via peptide transport mechanism and were rapidly converted to the active parent drugs by the intracellular hydrolysis.

Drug transport and targeting. Intestinal transport.

A wide variety of transporters are found in the intestine, and are involved in the membrane transport of daily nutrients as well as drugs. These intestinal transporters are located in the brush border membrane as well as basolateral membrane. Each transporter exhibits its own substrate specificity, and some have broader specificities than others. In addition, the distribution and characteristics of the intestinal transporters exhibit regional differences along the intestine, implying diverse physiologic functions and in some cases pathologic responses. Indeed several genetic disorders have been shown to result from deficient intestinal transporters. The development of prodrugs that target to intestinal transporters has been successful in improving oral absorption. For example, the intestinal peptide transporter is utilized in order to increase the bioavailability of several classes of peptidomimetic drugs, especially ACE inhibitors and beta-lactam antibiotics. The bioavailability of poorly absorbed drugs can be improved by utilization of the transporters responsible for the intestinal absorption of various solutes and/or by inhibiting the transporter involved in the efflux system. Recent advances in gene cloning and molecular biology techniques make it possible to study the characteristics and distribution of transporters at the molecular level. Based on molecular characterizations of membrane transporters and accumulated biochemical data on their specificities and kinetics, structural modification and targeting of a specific transporter is a promising strategy for the design of drugs that improve bioavailability and tissue distribution.

Cephalometric characteristics of Korean Class III surgical patients and their relationship to plans for surgical treatment.

In comparison to gender-matched normal Koreans, Korean patients selected for surgical correction of skeletal Class III problems have, on average, a shorter anterior and posterior cranial base, a shorter maxilla, a longer mandible, increased lower facial height, and a retrusive upper lip. In both males and females, about 40% of a group of Class III patients scheduled for surgery had a maxilla within one standard deviation of the normal position and a prognathic mandible, as compared with a group of normal Korean adults. Almost as many males (37%) in the surgical group had both a retrognathic maxilla and a prognathic mandible, while 18% had a retrognathic maxilla and normal mandible. In females, 25% had only a retrognathic maxilla and 25% had both jaws outside the normal range. The percentage of the Korean patients whose Class III relationship was primarily a result of mandibular prognathism (48%) is more than twice as high as the corresponding number for American Class III surgical patients (19%), somewhat higher than in Chinese patients (39%), and similar to the percentage of Japanese (50%). Maxillary surgery, alone or in conjunction with mandibular setback, is currently used in the treatment of most Class III patients. Both the esthetic consideration of widening the already broad Asian nose and the relative proportions of maxillary versus mandibular abnormalities suggest that mandibular setback alone can be considered for a higher number of Asian than Caucasian Class III patients.