Human Fibroblast-Derived Matrix Hydrogel Accelerates Regenerative Wound Remodeling Through the Interactions with Macrophages

Herein, a novel extracellular matrix (ECM) hydrogel is proposed fabricated solely from decellularized, human fibroblast-derived matrix (FDM) toward advanced wound healing. This FDM-gel is physically very stable and viscoelastic, while preserving the natural ECM diversity and various bioactive factors. Subcutaneously transplanted FDM-gel provided a permissive environment for innate immune cells infiltration. Compared to collagen hydrogel, excellent wound healing indications of FDM-gel treated in the full-thickness wounds are noticed, particularly hair follicle formation via highly upregulated β-catenin. Sequential analysis of the regenerated wound tissues disclosed that FDM-gel significantly alleviated pro-inflammatory cytokine and promoted M2-like macrophages, along with significantly elevated vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) level. A mechanistic study demonstrated that macrophages-FDM interactions through cell surface integrins α5β1 and α1β1 resulted in significant production of VEGF and bFGF, increased Akt phosphorylation, and upregulated matrix metalloproteinase-9 activity. Interestingly, blocking such interactions using specific inhibitors (ATN161 for α5β1 and obtustatin for α1β1) negatively affected those pro-healing growth factors secretion. Macrophages depletion animal model significantly attenuated the healing effect of FDM-gel. This study demonstrates that the FDM-gel is an excellent immunomodulatory material that is permissive for host cells infiltration, resorbable with time, and interactive with macrophages, where it thus enables regenerative matrix remodeling toward a complete wound healing.

Mesenchymal stem cell-derived secretomes-enriched alginate/ extracellular matrix hydrogel patch accelerates skin wound healing

BACKGROUND

The secretomes of mesenchymal stem cells (MSCs) have great therapeutic potential and thereby their efficient delivery into the target site is of particular interest. Here, we propose a new strategy of hMSCs-derived secretomes delivery for advanced wound healing upon harnessing the working principle of extracellular matrix (ECM)-growth factors interaction in vivo.

METHODS

We prepared an alginate hydrogel based wound patch, where it contains both human MSC-derived secretomes and ECM. The ECM was obtained from the decellularization of in vitro cultured human lung fibroblasts. The alginate solution was blended with ECM suspension, crosslinked, air-dried, then rehydrated with the secretomes contained in the concentrated conditioned media (CCM) as a highly saturated form of conditioned media (CM). We tested four different groups, with or without the ECM to investigate not only the role of ECM but the therapeutic effect of secretomes.

RESULTS

The secretomes reserved many, diverse bioactive factors, such as VEGF, HGF, IGFBPs, IL-6, and IL-8. Alginate/ECM/CCM (AEC) patch could hold significantly larger amount of secretomes and release them longer than the other groups. Our AEC patch was the most effective in stimulating not only cell migration and proliferation but the collagen synthesis of dermal fibroblasts in vitro. Moreover, the AEC patch-treated full-thickness skin wounds disclosed significantly better wound healing indications: cell recruitment, neovascularization, epidermis thickness, keratinocyte migration, and mature collagen deposition, as assessed via histology (H&E, Herovici staining) and immunofluorescence, respectively. In particular, our AEC patch enabled a phenotype shift of myofibroblast into fibroblast over time and led to mature blood vessel formation at 14 day.

CONCLUSIONS

We believe that ECM certainly contributed to generate a secretomes-enriched milieu via ECM-secretomes interactions and thereby such secretomes could be delivered more efficiently, exerting significant therapeutic impact either individually or collectively during wound healing process.

The novel KV7 channel activator URO-K10 exerts enhanced pulmonary vascular effects independent of the KCNE4 regulatory subunit

KV7 channels exert a pivotal role regulating vascular tone in several vascular beds. In this context, KV7 channel agonists represent an attractive strategy for the treatment of pulmonary arterial hypertension (PAH). Therefore, in this study, we have explored the pulmonary vascular effects of the novel KV7 channel agonist URO-K10. Consequently, the vasodilator and electrophysiological effects of URO-K10 were tested in rat and human pulmonary arteries (PA) and PA smooth muscle cells (PASMC) using myography and patch-clamp techniques. Protein expression was also determined by Western blot. Morpholino-induced knockdown of KCNE4 was assessed in isolated PA. PASMC proliferation was measured by BrdU incorporation assay. In summary, our data show that URO-K10 is a more effective relaxant of PA than the classical KV7 activators retigabine and flupirtine. URO-K10 enhanced KV currents in PASMC and its electrophysiological and relaxant effects were inhibited by the KV7 channel blocker XE991. The effects of URO-K10 were confirmed in human PA. URO-K10 also exhibited antiproliferative effects in human PASMC. Unlike retigabine and flupirtine, URO-K10-induced pulmonary vasodilation was not affected by morpholino-induced knockdown of the KCNE4 regulatory subunit. Noteworthy, the pulmonary vasodilator efficacy of this compound was considerably increased under conditions mimicking the ionic remodelling (as an in vitro model of PAH) and in PA from monocrotaline-induced pulmonary hypertensive rats. Taking all together, URO-K10 behaves as a KCNE4-independent KV7 channel activator with much increased pulmonary vascular effects compared to classical KV7 channel activators. Our study identifies a promising new drug in the context of PAH.

Bidirectional sensitivity of CALHM1 channel to protons from both sides of plasma membrane

Calcium homeostasis modulator 1 (CALHM1), a newly discovered voltage-dependent nonselective ion channel, has drawn attention for its role in neuronal activity and taste sensation. Its sluggish voltage-dependent activation is facilitated by lowering extracellular Ca²⁺ concentration ([Ca²⁺]_e). Here, we investigated the effects of extracellular and intracellular pH (pH_e and pH_i) on human CALHM1. When normalized to the amplitude of the CALHM1 current (I_CALHM1) under whole cell patch clamp at symmetrical pH 7.4, I_CALHM1 decreased at acidic pH_e or pH_i, whereas it sharply increased at alkaline pH_e or pH_i. The effects of pH were preserved in the inside-out configuration. The voltage dependence of I_CALHM1 showed leftward and rightward shifts at alkaline and acidic pH_e and pH_i, respectively. Site-directed mutagenesis of the water-accessible charged residues of the pore and nearby domains revealed that E17, K229, E233, D257, and E259 are nonadditively responsible for facilitation at alkaline pH_i. Identification of the pH_e-sensing residue was not possible because mutation of putative residues impaired membrane expression, resulting in undetectable I_CALHM1. Alkaline pH_e-dependent facilitation appeared gradually with depolarization, suggesting that the sensitivity to pH_e might be due to H⁺ diffusion through the open-state CALHM1. At pH_e 6.2, decreased [Ca²⁺]_e could not recover the inhibited I_CALHM1 but further augmented the increased I_CALHM1 at pH_e 8.6, suggesting that unidentified common residues might contribute to the [Ca²⁺]_e and acidic pH_e. This study is the first, to our knowledge, to demonstrate the remarkable pH sensitivity of CALHM1, which might contribute to the pH-dependent modulation of neuronal excitability or taste sensation.

Lower troponin expression in the right ventricle of rats explains interventricular differences in E-C coupling

Despite distinctive functional and anatomic differences, a precise understanding of the cardiac interventricular differences in excitation–contraction (E–C) coupling mechanisms is still lacking. Here, we directly compared rat right and left cardiomyocytes (RVCM and LVCM). Whole-cell patch clamp, the IonOptix system, and fura-2 fluorimetry were used to measure electrical properties (action potential and ionic currents), single-cell contractility, and cytosolic Ca²⁺ ([Ca²⁺]_i), respectively. Myofilament proteins were analyzed by immunoblotting. RVCM showed significantly shorter action potential duration (APD) and higher density of transient outward K⁺ current (I_to). However, the triggered [Ca²⁺]_i change (Ca²⁺ transient) was not different, while the decay rate of the Ca²⁺ transient was slower in RVCM. Although the relaxation speed was also slower, the sarcomere shortening amplitude (ΔSL) was smaller in RVCM. SERCA activity was ∼60% lower in RVCM, which is partly responsible for the slower decay of the Ca²⁺ transient. Immunoblot analysis revealed lower expression of the cardiac troponin complex (cTn) in RVCM, implying a smaller Ca²⁺ buffering capacity (κ_S), which was proved by in situ analysis. The introduction of these new levels of cTn, I_to, and SERCA into a mathematical model of rat LVCM reproduced the similar Ca²⁺ transient, slower Ca²⁺ decay, shorter APD, and smaller ΔSL of RVCM. Taken together, these data show reduced expression of cTn proteins in the RVCM, which provides an explanation for the interventricular difference in the E–C coupling kinetics.

M2 Macrophage-Derived Concentrated Conditioned Media Significantly Improves Skin Wound Healing

BACKGROUND

Macrophages, with many different phenotypes play a major role during wound healing process, secreting the cytokines crucial to angiogenesis, cell recruitment and ECM remodeling. Therefore, macrophage-derived cytokines may be attractive therapeutic resource for wound healing.

METHODS

To obtain a conditioned media (CM) from macrophages, human monocyte THP-1 cells were seeded on TCP or human fibroblast-derived matrix (hFDM) and they were differentiated into M1 or M2 phenotype using distinct protocols. A combination of different substrates and macrophage phenotypes produced M1- and M2-CM or M1-hFDM- and M2-hFDM-CM, respectively. Proteome microarray determines the cytokine contents in those CMs. CMs-treated human dermal fibroblast (hDFB) was analyzed using collagen synthesis and wound scratch assay. Concentrated form of the CM (CCM), obtained by high-speed centrifugation, was administered to a murine full-thickness wound model using alginate patch, where alginate patch was incubated in the M2-CCM overnight at 4 °C before transplantation. On 14 day post-treatment, examination was carried out through H&E and Herovici staining. Keratinocyte and M2 macrophages were also evaluated via immunofluorescence staining.

RESULTS

Cytokine analysis of CMs found CCL1, CCL5, and G-CSF, where CCL5 is more dominant. We found increased collagen synthesis and faster wound closure in hDFB treated with M2-CM. Full-thickness wounds treated by M2-hFDM-CCM containing alginate patch showed early wound closure, larger blood vessels, increased mature collagen deposition, enhanced keratinocyte maturation and more M2-macrophage population.

CONCLUSION

Our study demonstrated therapeutic potential of the CM derived from M2 macrophages, where the cytokines in the CM may have played an active role for enhanced wound healing.

Intramolecular Disulfide Bonds for Biogenesis of CALHM1 Ion Channel Are Dispensable for Voltage-Dependent Activation

Calcium homeostasis modulator 1 (CALHM1) is a membrane protein with four transmembrane helices that form an octameric ion channel with voltage-dependent activation. There are four conserved cysteine (Cys) residues in the extracellular domain that form two intramolecular disulfide bonds. We investigated the roles of C42-C127 and C44-C161 in human CALHM1 channel biogenesis and the ionic current (ICALHM1). Replacing Cys with Ser or Ala abolished the membrane trafficking as well as ICALHM1. Immunoblotting analysis revealed dithiothreitol-sensitive multimeric CALHM1, which was markedly reduced in C44S and C161S, but preserved in C42S and C127S. The mixed expression of C42S and wild-type did not show a dominant-negative effect. While the heteromeric assembly of CALHM1 and CALHM3 formed active ion channels, the co-expression of C42S and CALHM3 did not produce functional channels. Despite the critical structural role of the extracellular cysteine residues, a treatment with the membrane-impermeable reducing agent tris(2-carboxyethyl) phosphine (TCEP, 2 mM) did not affect ICALHM1 for up to 30 min. Interestingly, incubation with TCEP (2 mM) for 2-6 h reduced both ICALHM1 and the surface expression of CALHM1 in a time-dependent manner. We propose that the intramolecular disulfide bonds are essential for folding, oligomerization, trafficking and maintenance of CALHM1 in the plasma membrane, but dispensable for the voltage-dependent activation once expressed on the plasma membrane.

Thermosensitivity of the voltage-dependent activation of calcium homeostasis modulator 1 (calhm1) ion channel

Calcium homeostasis modulator 1 (calhm1) proteins form an outwardly rectifying nonselective ion channel having exceedingly slow kinetics and low sensitivity to voltage that is shifted by lowering extracellular Ca²⁺ ([Ca²⁺]_e). Here we found that physiological temperature dramatically facilitates the voltage-dependent activation of the calhm1 current (I_calhm1); increased amplitude (Q₁₀, 7-15) and fastened speed of activation. Also, the leftward shift of the half-activation voltage (V_1/2) was similary observed in the normal and lower [Ca²⁺]_e. Since calhm1 is highly expressed in the brain and taste cells, the thermosensitivity should be considered in their electrophysiology.

Management of isolated recurrence after surgery for pancreatic adenocarcinoma

BACKGROUND

Recurrence of pancreatic cancer after primary pancreatectomy occurs in the vast majority of patients. The role of surgical treatment for recurrent pancreatic cancer is not well established.

METHODS

Patients who underwent primary pancreatectomy with curative intent from 2000 to 2014 at a single large-volume centre were evaluated retrospectively. CT or PET was used to select patients with an isolated recurrence. The clinicopathological features and survival outcomes were compared according to treatment modalities.

RESULTS

Of the 1610 patients with pancreatic cancer who underwent resection, 1346 (83·6 per cent) were diagnosed with recurrent pancreatic cancer. Recurrence was locoregional in 366 patients (27·2 per cent), distant multifocal in 251 (18·6 per cent), distant isolated in 188 (14·0 per cent), locoregional plus distant in 153 (11·4 per cent) and peritoneal seeding in 388 (28·8 per cent). Of the 1346 patients with recurrence, 197 (14·6 per cent) had isolated recurrence; of these, 48 (24·4 per cent of all isolated recurrences; 3·6 per cent of all recurrences) underwent resection. Median survival of the 197 patients after diagnosis of isolated recurrence was 14·7 months; it was longer in patients who underwent surgical resection than among those treated non-surgically (23·5 versus 12·0 months; P = 0·014). Multivariable analysis showed that chemotherapy and resection for recurrence were associated with better prognosis. Median survival after recurrence was longest in the 23 patients with isolated pulmonary recurrence (33·3 months). Survival after recurrence was better in patients who underwent resection of isolated recurrence in the remnant pancreas (median 28·0 versus 12·0 months, P = 0·010) and lung (median 36·5 versus 9·5 months; P = 0·010) than in those who did not undergo resection.

CONCLUSION

Surgical resection may be considered an option for treatment of patients with isolated recurrent pancreatic cancer.

Monitoring rate and predictability of intraoperative monitoring in patients with intradural extramedullary and epidural metastatic spinal tumors

STUDY DESIGN

Single-center retrospective study.

OBJECTIVES

To evaluate the monitoring rate, sensitivity and specificity of intraoperative monitoring (IOM) during removal of intradural extramedullary (IDEM) or epidural metastatic spinal tumors. Also, to assess the efficacy of monitoring somatosensory-evoked potentials (SSEP) when motor-evoked potentials (MEP) are not measurable.

SETTING

The Neuro-Oncology Clinic, National Cancer Center, Korea.

METHODS

Patients (n=101) with IDEM or epidural metastatic spinal tumors at the cord level underwent surgeries monitored with SSEP and/or MEP. The monitoring rate was defined as negative when MEP or SSEP could not be measured after reversal of the neuromuscular block under general anesthesia. Positive IOM changes included more than a 50% change in the MEP or SSEP amplitude and more than a 10% delay in SSEP latency.

RESULTS

MEP was measurable in 73% of patients. The MEP monitoring rate in patients with motor power grades of 3 or less was 39%, which was lower than that of SSEP (83%). The sensitivity, specificity and predictability of MEP for motor changes were 93, 90 and 91%, respectively. Conversely, the sensitivity, specificity and predictability of SSEP were 62, 97 and 89%, respectively. In patients in whom MEP was not measurable (n=24), SSEP was monitored with a predictability of 83%.

CONCLUSION

In cases of extramedullary spinal tumors, MEP shows a higher sensitivity than SSEP does. However, the monitoring rate of MEP in non-ambulatory patients was lower than that of SSEP. In those cases, SSEP can be useful to monitor for postoperative neurological deficits.

Immature Rubus coreanus Shows a Free Radical-Scavenging Effect and Inhibits Cholesterol Synthesis and Secretion in Liver Cells

Rubus coreanus fruits have been employed as a traditional medicine for centuries in the Asia-Pacific region. Its pharmacological action differs according to the different extraction methods utilized and the degree of fruit ripening. In this study, we determined the cellular effect of different ethanol extracts of mature and immature Rubus coreanus fruits in human hepatic cell line, HepG2 cells. The antioxidant activity, effect on superoxide dismutase activity and cholesterol biosynthesis efficiency was also evaluated. Immature Rubus coreanus extract showed higher antioxidant capability, compared with that of its mature fractions. Cellular antioxidant proteins including HO-1, Cu/Zn-superoxide dismutase and catalase were highly expressed in the presence of Rubus coreanus. Cholesterol levels in HepG2 cells treated with the water fraction of immature Rubus coreanus were significantly reduced. This antihyperlipidaemic action of Rubus coreanus is a consequence of cholesterol biosynthesis and extracellular secretion in HepG2 cells. These results indicate that among different ethanol fraction of mature and immature Rubus coreanus fruit extracts, water extract of immature fruit extract shows higher antioxidant as well as higher antihyperlipidaemic action.

Prevalence of atopy and allergic diseases in Korean children: associations with a farming environment and rural lifestyle

BACKGROUND

The results of recent studies suggest that factors in rural environments may protect against the development of allergic diseases, but the underlying mechanisms are not well understood. The aim of this study was to investigate the prevalence of allergic diseases, to establish if this prevalence is influenced by migration from rural to urban areas and to identify environmental risk factors associated with these diseases.

METHODS

A cross-sectional study of children aged 9-12 years from a rural village, a rural town and an urban city in Korea was conducted. Demographic and disease-related information was obtained via a detailed questionnaire, and skin prick tests were performed.

RESULTS

There were significant differences in lifestyle and environmental factors between children from the rural village, the rural town and the urban children. The prevalence of allergic diseases and atopy was higher in urban children. A lower prevalence of allergic diseases and atopy was associated with farming parents, contact with farm animals during pregnancy, owning pets or a stable, breast-feeding and having older siblings. A comparison of rural village and rural town children revealed no evidence of an association of allergic diseases and atopy with farming parents, contact with farm animals during pregnancy or owning a stable. On the other hand, having older siblings and antibiotic use during infancy were significantly associated with allergic diseases and atopy in these children.

CONCLUSIONS

Protective factors associated with a farming environment and/or rural lifestyle may influence the prevalence of allergic diseases and atopy in Korean children.

Longitudinal split of the posterior cruciate ligament: description of a new MR finding and evaluation of its potential clinical significance

AIM

To evaluate the clinical significance of the intra-substance longitudinal split of the posterior cruciate ligament (LS-PCL) and to evaluate its potential clinical significance on MRI.

MATERIALS AND METHODS

The databases of two centres were searched for LS-PCL, 6917 knee magnetic resonance imaging (MRI) examinations undertaken were retrospectively reviewed. LS-PCL was defined as increased signal intensity in a PCL in the longitudinal direction, but with an intact ligament outer surface on MRI. Twelve patients were enrolled in this study. Available arthroscopic results, degree of posterior knee instability, and changes in MRI findings, or the degree of instability during follow-up (FU), were reviewed from the patients medical records and via their MRI images. MRI images were reviewed by two musculoskeletal radiologists in consensus for presence and location of LS-PCL and any combined injuries: menisci lesions, ligament injuries, and bone marrow changes.

RESULTS

Seven of 12 patients (58.3%) had morphological or functional evidence of PCL injury or insufficiency according to the change of posterior instability on FU stress testing (n=3), insufficiency during arthroscopy (n=2), or decreased extent and altered shape of the PCL split on the FU MRI (n=3). One patient revealed both change of posterior instability on FU stress testing and insufficiency during arthroscopy. Combined injuries were revealed in seven patients. Five patients had isolated LS-PCL: two patients underwent arthroscopic PCL reconstructions; and another three patients revealed knee instability on stress testing.

CONCLUSION

Although LS-PCL has not been described before, it can be a type of partial tear of the PCL, which causes PCL insufficiency.

Secular trends in adult male smoking from 1992 to 2006 in South Korea: age-specific changes with evolving tobacco-control policies

OBJECTIVES

For years, South Korea has had one of the highest levels of tobacco use among males in the world, but a steady decline has been observed recently. This study examined how the smoking behaviour of male adults changed with age after the implementation of national tobacco control policies in 1995.

STUDY DESIGN

Repeated cross-sectional study using a national survey.

METHODS

Data were obtained from the 1992, 1995, 1999, 2003 and 2006 results of a repeated cross-sectional survey, the Social Statistics Survey. The smoking status of adult men was compared before (1992 and 1995 surveys) and after (1999, 2003 and 2006 surveys) the implementation of government-directed tobacco control policies using graphical methods and logistic regression analysis.

RESULTS

After the implementation of tobacco control policies, the percentage of current male smokers decreased while the percentage of former smokers increased markedly. Smoking prevalence among older men (aged 50 years or more) reduced initially, and this decline was more pronounced after the tobacco control policies were implemented. Smoking prevalence in younger men (aged 30-49 years) declined in 2003 when more comprehensive tobacco control policies were implemented.

CONCLUSIONS

This study suggests that comprehensive tobacco control policies in South Korea reduced smoking prevalence among males, initially among older men and later among both older men and younger men.

Which oblique plane is more helpful in diagnosing an anterior cruciate ligament tear?

AIM

To evaluate the diagnostic role of additional oblique coronal and oblique sagittal magnetic resonance imaging (MRI) for an anterior cruciate ligament (ACL) tear.

MATERIALS AND METHODS

A total of 101 patients who had undergone preoperative knee MRI examinations with orthogonal and two sets of oblique images were enrolled in the study. Two radiologists evaluated the MRI images by the use of four methods: orthogonal images only (method A); orthogonal and additional oblique coronal images (method B); orthogonal and oblique sagittal images (method C); and orthogonal images with oblique coronal and sagittal images (method D). The status of the ACL (normal or tear) was determined by consensus. The sensitivity, specificity, and accuracy for an ACL tear with the use of each method were calculated in comparison with arthroscopy as the reference standard, and values were statistically analysed using the McNemar test. The diagnostic accuracies were compared using receiver operating characteristic (ROC) analysis.

RESULTS

Arthroscopy identified 10 partial ACL tears and 30 complete ACL tears. The specificities and accuracies for methods B, C, and D were significantly higher than the specificities and accuracies for method A (p<0.05). There was no significant difference in the sensitivity, specificity, and accuracy for methods B, C, and D. Diagnostic ability was not significantly different for each method, as determined by ROC analysis (p>0.05).

CONCLUSIONS

Additional oblique imaging for an ACL tear improved the specificity. Either of the oblique imaging methods is sufficient, and no further improvement in the diagnostic efficacy was achieved by simultaneous use.

Release of Ciprofloxacin from Chondroitin 6-Sulfate-Graft-Poloxamer Hydrogel In Vitro for Ophthalmic Drug Delivery

The system was designed to use Poloxamer as a vehicle for ophthalmic drug delivery using in situ gel formation property. To enhance the wound healing and cell adhesion as well as transparency of Poloxamer hydrogel, chondroitin 6-sulfate (C6S) was introduced into Poloxamer. For this purpose, mono amine-terminated Poloxamer (MATP), which was end-capped with ethylene amine group only in one side of terminal hydroxyl groups of Poloxamer, was synthesized. Subsequently, C6S-graft-Poloxamer copolymer (C6S-g-Poloxamer) was prepared by reaction between the amine groups of MATP and carboxyl groups of C6S in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carboimide (EDC). The coupling of MATP with C6S was clarified by 1H-NMR and FT-IR spectroscopy. The gelation temperature of graft copolymers was determined by measuring the temperature at which immobility of the meniscus in each solution was first noted. Release behavior of ciprofloxacin from C6S-g-Poloxamer hydrogel in vitro was investigated as a function of C6S content in the graft copolymer by a spectrophotometric assay at 287 nm using an UV spectrophotometer. Differences in the adhesion and morphology of human lens cell between Poloxamer- and C6S-g-Poloxamer-coated surfaces were also investigated. The gelation temperatures of C6S-g-Poloxamer copolymers were lowered with increasing of the concentration of the copolymer and decreasing of C6S content. The release of ciprofloxacin from the graft copolymer was sustained compared with Poloxamer itself and decreased with increasing the content of C6S in the copolymer due to the in situ gel formation of the copolymer and viscous properties of C6S. Human lens cells (B3) adhered to C6S-g-Poloxamer-coated surface were observed as transformed shapes after 2 days. The bioadhesive and thermally gelling of these graft copolymers will be expected to be an excellent drug carrier for the prolonged delivery to surface of the eye.

Pharmacokinetic and pharmacodynamic consequences of inhibition of terazosin metabolism via CYP3A1 and/or 3A2 by DA-8159, an erectogenic, in rats

BACKGROUND AND PURPOSE

Recently, orthostatic hypotension was observed in patients with benign prostatic hyperplasia who are taking vardenafil (a PDE 5 inhibitor) and terazosin (a long acting alpha blocker). Therefore, this study was performed with DA-8159 (a long acting PDE 5 inhibitor) and terazosin in rats to find whether or not pharmacokinetic and pharmacodynamic interactions between the two drugs were observed.

EXPERIMENTAL APPROACH

Pharmacokinetic and pharmacodynamic (changes in blood pressure) interactions between DA-8159 and terazosin were evaluated after simultaneous i.v. and p.o. administration of DA-8159 (30 mg kg(-1)) and terazosin (5 mg kg(-1)) to male Sprague-Dawley rats.

KEY RESULTS

After simultaneous i.v. and p.o. administration of terazosin and DA-8159, the total area under the plasma concentration-time curve from time zero to time infinity (AUC) of terazosin became significantly greater (57.4 and 75.4% increase for i.v. and p.o. administration, respectively) than those of without DA-8159. The blood pressure dropping effect was considerable after simultaneous p.o. administration of DA-8159 and terazosin compared with each drug alone.

CONCLUSIONS AND IMPLICATIONS

The significantly greater AUC of terazosin after both simultaneous i.v. and p.o. administration of both drugs could be due to the hepatic (both i.v. and p.o.) and intestinal (p.o.) inhibition of the metabolism of terazosin via CYP3A1 and/or 3A2 by DA-8159, since both DA-8159 and terazosin are metabolized via CYP3A1 and/or 3A2 in rats. The blood pressure lowering effect after simultaneous p.o. administration of both drugs could be due to significant increase in plasma concentrations of terazosin.

Evaluation of the photoneutron field produced in a medical linear accelerator

The doses and spectra of photoneutrons produced in a medical linear accelerator with photon energies of 10 and 15 MV were evaluated. The Monte Carlo code, MCNPX, was used to simulate the transport of these photoneutrons around the head for 10 and 15 MV photons. The fully-described geometry of the accelerator head was used in this calculation. The photoneutron energy spectra and doses for various photon field sizes were calculated at each of 20 positions. The results indicate that the maximum dose equivalents are observed in 20 x 20 cm(2) case among photon fields. It was found the neutron average energy at isocenter for a 0 x 0 cm(2) field is 0.38 MeV for 10 MV and is 0.45 MeV for 15 MV. The neutron doses at 10 positions around the head in the treatment room of the operation facility at 10 and 15 MV were measured using the bubble detectors. Measurements were compared with the calculations under the same geometry in the experiment. It was found that the majority of the calculated results agreed to within the standard deviations of the measurements. These above results can be applied in the verification of maximum allowed neutron leakage percentage of treatment dose defined in the IEC. We have been employing them to derive the empirical formula for neutron dose equivalent level at the maze entrance of medical accelerator treatment rooms in a study that is still underway.

MR imaging of the brain in Wilson disease of childhood: findings before and after treatment with clinical correlation

BACKGROUND AND PURPOSE

Although brain MR imaging findings in adult Wilson disease have been described in considerable detail, a paucity of information currently exists regarding brain MR imaging findings in pediatric Wilson disease. The purpose of this study was to analyze the brain MR imaging findings in Wilson disease of childhood at the initial stage and during follow-up after treatment and to correlate these observations with clinical response.

METHODS

We evaluated 50 patients with pediatric Wilson disease. Fifty initial and 20 follow-up MR images from 15 patients following penicillamine treatment were analyzed retrospectively, and the data were correlated with clinical findings.

RESULTS

Patients were categorized into 3 groups on the basis of initial MR imaging findings. Group I (n = 23) showed normal MR imaging findings. Group II (n = 15) was characterized by T1-weighted images with increased signal intensity in the globus pallidus (n = 15, 100%) followed by the putamen, midbrain, and caudate nucleus. Group III (n = 12) demonstrated T2-weighted images with increased signal intensity in the putamen (n = 10, 83%), followed by the caudate nucleus, globus pallidus, thalamus, midbrain, and pons. There was a significant difference in mean age, the presence of neurologic symptoms, and Child-Pugh classification among the 3 groups (P < .001). Following copper chelating therapy, the changes on follow-up MR imaging were strongly correlated with clinical response to treatment (P < .001).

CONCLUSION

Brain MR imaging in children with Wilson disease can be categorized into distinct groups and demonstrated a significant correlation with clinical findings. Interval changes on follow-up MR imaging were also closely correlated with clinical findings and helpful in assessing the clinical response.

The effect of DA-8159, a novel PDE5 inhibitor, on erectile function in the rat model of hypercholesterolemic erectile dysfunction

This study examined the effects of a new phosphodiesterase type 5 inhibitor, DA-8159, on erectile function associated with hypercholesterolemia. First of all, in order to investigate whether chronic administration of DA-8159 prevents the development of erectile dysfunction associated with hypercholesterolemia, male SD rats were divided into four groups (normal control, hypercholesterolemic control, DA-8159 5 or 20 mg/kg/day). Over a 5-month period, the animals were fed a 2% cholesterol diet and administered DA-8159 orally once a day. After 5 months, the electrostimulation-induced penile erection and the vascular function using acetylcholine-induced vasodilation with endothelium-intact aortic rings were examined. Furthermore, the plasma lipid profiles, endothelin and N(G),N(G)-dimethylarginine (asymmetrical dimethylarginine, ADMA) concentrations were measured. In order to investigate the acute treatment effect of DA-8159 on the erectile function in an established hypercholesterolemic model, additional animals were given a 2% cholesterol diet for 5 months without DA-8159. At the end of 5 months, the rats were divided into three groups (hypercholesterolemic control, DA-8159 0.3 or 1 mg/kg). DA-8159 was administered intravenously 1 min prior to the intracavernous pressure (ICP) measurement. In a chronic treatment study, while the hypercholesterolemic control showed a significantly lower erectile function, vascular reactivity, and increased plasma cholesterol, endothelin and ADMA concentration, the chronic DA-8159 treatment clearly restored the erectile responses by electric stimulation, preserved the potential of thoracic aortic relaxation in a dose-dependent manner, and significantly decreased the plasma endothelin and ADMA concentrations. In an acute treatment study, DA-8159 induced a dose- and frequency-dependent increase in ICP. The ICP/BP ratio and the corresponding AUC values, and the detumescence time were also significantly increased compared to the hypercholesterolemic control. These results suggest that DA-8159 is beneficial for erectile dysfunction in a rat hypercholesterolemic model and provided a rationale for the potential use of DA-8159 for treating erectile dysfunction secondary to hypercholesterolemia.

Dehydrocostus lactone enhances tumor necrosis factor-alpha-induced apoptosis of human leukemia HL-60 cells

Sesquiterpene lactones have raised considerable interest because of their ability to block the activation of nuclear transcription factor-kappaB (NF-kappaB). NF-kappaB plays an important role in the resistance of cancer cells to the induction of apoptosis by anticancer drugs and tumor necrosis factor-alpha (TNF-alpha). Pharmacological inhibition of NF-kappaB offers the promise of enhancing the efficacy of anticancer therapies. Here, we demonstrate that dehydrocostus lactone (DL), the major sesquiterpene lactone isolated from the roots of Saussurea lappa, inhibits NF-kappaB activation by preventing TNF-alpha-induced degradation and phosphorylation of its inhibitory protein I-kappaB alpha in human leukemia HL-60 cells and that DL renders HL-60 cells susceptible to TNF-alpha-induced apoptosis by enhancing caspase-8 and caspase-3 activities.

The effect of PDE5 inhibition on the erectile function in streptozotocin-induced diabetic rats

The aim of this study was to assess the effect of phosphodiesterase 5 inhibitor, DA-8159, on erectile function throughout the quantitative analysis of vascular endothelial cell, smooth muscle (SM), TGF-beta1 expression in rat corpus cavernosum and measurement of intracavernous pressure (ICP) in diabetic rats. DA-8159 (0, 5, 10, 20 mg/kg) was administered orally once a day to diabetic rats. After 8 weeks, immunohistochemistry and computerized image analysis were performed to quantify the percent area within the Corpora Cavernosa occupied by the endothelial cells, SM cells and fibrotic tissues. ICP/mean arterial pressure (MAP) was also measured by electrostimulation of the cavernous nerve. Diabetic rats showed a significant decrease in the SM and endothelial cell content, and an increase in the TGF-beta1 expression level within the cavernosa areas compared to the normal rats. The mean cavernous SM, endothelial cell content and TGF-beta1 expression level were 9.7+/-0.7, 4.5+/-0.7 and 17.9+/-2.1%, respectively. DA-8159 prevented reduction of SM (12.3+/-0.4% (5 mg/kg), 13.8+/-0.4% (20 mg/kg)) and endothelial cell content (5.6+/-0.5% (5 mg/kg), 6.3+/-0.6% (20 mg/kg)). Immunoreactivity of TGF-beta1 and intracorporal fibrosis were also significantly lower in DA-8159-treated groups (11.8+/-1.2% (5 mg/kg), 9.5+/-1.1% (20 mg/kg)). Electrostimulation of the cavernous nerve induced significant increase in maximum ICP (62.2+/-13.6 mmHg in 10 mg/kg vs 37.5+/-17.5 mmHg in diabetic group) and area under the curve of the ratio of ICP/MAP (8891.09+/-1957 in 10 mg/kg vs 6315.87+/-2272 in diabetic group). These results suggest that subchronic treatment of DA-8159 can prevent the development of erectile dysfunction (ED), and provides a rationale for the use of DA-8159 as treatment of diabetic ED.

In Vitro Cytotoxicity of Mokko Lactone in Human Leukemia HL‐60 Cells: Induction of Apoptotic Cell Death by Mitochondrial Membrane Potential Collapse

We studied the effect of mokko lactone (ML) isolated from the roots of Saussurea lappa (Compositae), a plant that is used for medicinal purposes in Korea, on the induction of apoptosis in human leukemia HL-60 cells. ML was cytotoxic to HL-60 cells, and this cytotoxic effect of ML appears to be attributable to its induction of apoptotic cell death, as ML induced nuclear morphologic changes and internucleosomal DNA fragmentation and increased the proportion of Annexin V-positive cells and the activity of caspase-3. Further studies revealed that the induction of apoptosis by ML was associated with the loss of mitochondrial membrane potential. Collectively, our results suggest that apoptosis induced by ML in HL-60 cells was executed by a collapse of mitochondrial membrane potential followed by the activation of caspase-3. This is the first report on the mechanism of apoptosis-inducing effect of ML.

Comparative bioavailability of silibinin in healthy male volunteers

AIM

To study a comparative bioavailability of Liverman capsule to Legaion capsule and Silymarin tablet (which contain silibinin) in 24 healthy volunteers.

VOLUNTEERS AND METHODS

Twenty-four healthy male Korean volunteers received each medicine at the silibinin dose of 120 mg in a 3 x 3 crossover study. There was a 1-week washout period among the doses. Plasma concentrations of silibinin were monitored by a high-performance liquid chromatography for over a period of 12 hours after the administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated by the trapezoidal rule extrapolation method. Cmax (maximum plasma drug concentration) and tmax (time to reach a Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf, AUC(0-12h), and Cmax and untransformed tmax.

RESULTS

After an oral administration of Liverman capsule, the pharmacokinetic parameters of silibinin, such as AUC(0-12h) (5.59, 4.24 and 13.9 microg/ml x h for Legalon capsule, Silymarin tablet and Liverman capsule, respectively) and AUCinf (6.00, 4.63 and 15.1 microg/ml x h) were significantly greater, Cmax (1.33, 1.13 and 6.04 microg/ml) was significantly higher and tmax (1.83, 2.10 and 0.875 h) was significantly faster than those after Legalon capsule and Silymarin tablet.

CONCLUSION

These results indicate that the absorption and the extent of relative oral bioavailability of silibinin after Liverman capsule were significantly faster and greater, respectively, than those after Legalon capsule and Silymarin tablet.

In vitro and in vivo study of lens refilling with poloxamer hydrogel

AIM

To evaluate the compatibility of poloxamer hydrogel as a material for an injectable intraocular lens, in vivo and in vitro.

METHODS

The appropriate concentration of poloxamer hydrogel was determined for injection by examining the transparency and gelling temperature of this material, assessing the lens capsule refilling technique, and studying the postoperative findings in a rabbit model.

RESULTS

Poloxamer hydrogel showed excellent transparency and 25% was identified as an appropriate concentration for the lens refilling material. The authors developed a technique for injecting the material in vivo and obtained excellent short term results.

CONCLUSIONS

Poloxamer hydrogel was identified as an appropriate material for direct lens refilling, and the developed injection technique produced excellent short term results.

Efficacy of DA-8159, a new PDE5 inhibitor, for inducing penile erection in rabbits with acute spinal cord injury

DA-8159 is a pyrazolopyrimidinone derivative which exhibits potent and selective phosphodiesterase type 5 (PDE5) inhibition. The aim of this study was to investigate the effects of DA-8159 on inducing a penile erection in rabbits with an acute spinal cord injury (ASCI). DA-8159 was given either orally (1, 3, or 10 mg/kg) or intravenously (0.1 or 0.3 mg/kg) to conscious male albino rabbits with a surgical transection of the spinal cord at the L2-L4 lumbar vertebra or ischemic-reperfusion SCI rabbits. Erection was evaluated in a time-course manner by measuring the length of the uncovered penile mucosa. DA-8159 induced a dose-dependent erection in both transection and ischemic-reperfusion ASCI rabbits. The efficacy of DA-8159 was potentiated by an intravenous injection of sodium nitroprusside, a nitric oxide donor. Potentiation of the effect by nitric oxide donor implies that DA-8159 can enhance the erectile activity during sexual arousal. These results suggest that DA-8159 may be useful for treating erectile dysfunction in patients with an SCI.

No effect of cysteine on the pharmacokinetics of intravenous azosemide in rats with protein-calorie malnutrition by pretreatment with 3-methylcholanthrene

The effects of cysteine on the pharmacokinetics of azosemide were investigated after intravenous administration of drug, 10 mg/kg, to male Sprague-Dawley rats pretreated with 3-methylcholanthrene fed on 23% protein diet (control rats) and 5% protein diet without (rats with protein-calorie malnutrition, PCM) or with (rats with PCMC) oral cysteine (250 mg/kg, twice daily starting from the fourth week) for 4 weeks. After intravenous administration to rats with PCM, the metabolites of azosemide excreted in urine and recovered from gastrointestinal tract decreased significantly than those in control rats, however, the plasma concentrations, total area under plasma concentration-time curve from time zero to time infinity (AUC) and time-averaged total body clearance (CL) were not significantly different between two groups of rats. It was reported that after intravenous administration of azosemide, 10 mg/kg, to rats with PCMC without pretreatment 3-methylcholanthrene, some pharmacokinetic parameters restored fully or more than the level of control rats; the time-averaged nonrenal clearance and apparent volume of distribution at steady state were comparable to those in control rats, but the terminal half-life and mean residence time were significantly shorter, AUC was significantly smaller, and time-averaged renal clearance and CL were significantly faster than those in control rats. However, the above mentioned effects of cysteine on the pharmacokinetic parameters of azosemide in rats with PCM were not observed with pretreatment with 3-methylcholanthrene.

Pharmacokinetics, stability, and blood partition of DA-8159, a new phosphodiesterase V inhibitor

The pharmacokinetics of DA-8159, a new phosphodiesterase V inhibitor, after 1 min intravenous, 30 mg/kg, and oral, 30 mg/kg, administration of the drug to rats, the stability of DA-8159 in various pH solutions ranging from 1 to 13, and human and rat plasma and urine, and the blood partition of DA-8159 between plasma and blood cells of rabbit were evaluated. After intravenous administration, DA-8159 was eliminated fast with the mean total body clearance of 126 ml/min/kg, and was almost completely metabolized in rats; 5.98% of intravenous dose of DA-8159 were excreted unchanged in 24-hr urine. The extent of absolute oral bioavailibility of DA-8159 was approximately 25%. The apparent volume of distribution at steady state was considerably large, 15048 ml/kg, suggesting that DA-8159 has a good affinity to rat tissues. DA-8159 was relatively stable in various pH solutions, and human and rat plasma and urine for up to 48 h incubation in a water-bath shaker kept at 37 degrees C and at a rate of 50 oscillations per min. DA-8159 reached equilibrium fast (within 30 sec mixing manually) between plasma and blood cells of rabbit blood and the plasma-to-blood cell concentration ratios were independent of initial blood concentrations of DA-8159, 1, 5, and 10 microg/ml, when the rabbit whole blood was incubated for up to 120 min; the ratios were in the range of 0.662-0.812. There was no in vitro 'blood storage effect' in the plasma concentration of DA-8159.

Effects of cysteine on the pharmacokinetics of intravenous phenytoin in rats with protein-calorie malnutrition

The effects of cysteine on the pharmacokinetics of phenytoin and one of its metabolites, 5-(p-hydroxyphenyl)-5-phenylhydantoin (pHPPH) were investigated after intravenous administration of phenytoin, 25 mg/kg, to control rats (4-week fed on 23% casein diet) and rats with PCM (protein-calorie malnutrition, 4-week fed on 5% casein diet) and PCMC (PCM with oral cysteine supplementation, 250 mg/kg, twice daily starting from the fourth week). In rats with PCM and PCMC, the phenytoin hydroxylation (to form pHPPH) activities were significantly smaller (164, 103 and 95.3 pmol/min per mg protein for the control rats, and rats with PCM and PCMC, respectively) than that in control rats. In rats with PCMC, the intrinsic clearance of phenytoin, CL(int) was significantly slower than those in control rats and rats with PCM (0.175, 0.131 and 0.044 ml/min). The above data suggested that the formation of pHPPH could be reduced in rats with PCM and PCMC. This was supported by significantly smaller 24-h urinary excretion of pHPPH (54.7, 35.6 and 32.5% of intravenous dose of phenytoin) in rats with PCM and PCMC than that in control rats. In rats with PCM, the maximum velocity (0.344, 0.203 and 0.196 microg/min), apparent volume of distribution in central compartment (44.4, 65.4 and 72.2 ml/kg) of phenytoin, and total area under the plasma concentration-time curve from time zero to time infinity (609, 714 and 1210 microg min/ml), renal clearance (20.5, 13.4 and 4.67 ml/min per kg) and 24-h urinary excretion (54.7, 35.6 and 32.5% of intravenous dose of phenytoin) of pHPPH were not returned to control levels by cysteine supplementation (rats with PCMC). This could be mainly due to the fact that the phenytoin hydroxylation activity in rats with PCMC was not returned to control level.

Bioequivalence of clarithromycin tablet formulations assessed in Korean males

AIM

Determination of the bioequivalence of 2 clarithromycin tablet formulations manufactured in Korea.

PATIENTS AND METHODS

Twenty-four healthy male Korean volunteers received each of the 2 clarithromycin formulations at a dose of 250 mg in a 2 x 2 crossover study. There was a one-week washout period between doses. Plasma concentrations of clarithromycin were monitored by high-performance liquid chromatography over a period of 12 hours after administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated using the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and Tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf and Cmax and untransformed Tmax.

RESULTS

The point estimates and 90% confidence intervals for AUCinf (parametric) and Cmax (parametric) were 0.971 (0.886 approximately 1.063) and 0.982 (0.868 approximately 1.107), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. The corresponding value of Tmax was 0.000 (-0.250 approximately 0.250).

CONCLUSION

These results indicate that the 2 medications of clarithromycin are bioequivalent and, thus, may be prescribed interchangeably.

Cerebellopontine angle ganglioglioma: MR findings

We present a case of cerebellopontine (CP) angle ganglioglioma in a young child with developmental delay and no trigeminal nerve symptoms. MR imaging demonstrated a mass of homogeneous low signal intensity in the left CP angle on T1-weighted images with no enhancement with gadolinium, and of relatively homogeneous high signal intensity on T2-weighted images.

Subacute toxicities and toxicokinetics of a new erectogenic, DA-8159, after single and 4-week repeated oral administration in dogs

The subacute toxicities and toxicokinetics of a new erectogenic, DA-8159, were evaluated after single (at the 1st day) and 4-week (at the 28th day) oral administration of the drug, in doses of 0 (to serve as a control), 12.5, 50 and 200 mg/kg/day, to male and female dogs (n=3 for male and female dogs for each dose). DA-8159 had an effect on the immune-related organs (or tissues), circulatory systems, liver, adrenal glands, ovaries and pancreas. The toxic dose was 200 mg/kg and no observed adverse effect level was less than 50 mg/kg for male and female dogs. There were no significant gender differences in the pharmacokinetic parameters of DA-8159 for each dose after both single and 4-week oral administration. The pharmacokinetic parameters of DA-8159 were dose-independent after single oral administration; the time to reach a peak plasma concentration (T(max)) and the dose-normalized area under the plasma concentration-time curve from time zero to 24 h in plasma (AUC(0-24 h)) were not significantly different among three doses. However, accumulation of DA-8159 after 4-week oral administration was considerable at toxic dose, 200 mg/kg/day. For example, after 4-week administration, the dose-normalized AUC(0-24 h) value at 200 mg/kg/day (4.71 and 15.3 microg h/ml) was significantly greater than that at 12.5 mg/kg/day. After 4-week oral administration, the dose-normalized C(max) and AUC(0-24 h) at 200 mg/kg/day were significantly higher and greater, respectively, than those after a single oral administration.

Effects of cysteine on the pharmacokinetics and pharmacodynamics of intravenous and oral azosemide in rats with protein-calorie malnutrition

The effects of cysteine on the pharmacokinetics and pharmacodynamics of azosemide were investigated after intravenous (10 mg/kg) and oral (20 mg/kg) administration to male Sprague-Dawley rats fed on 23% protein diet (control rats), and 5% protein diet with (rats with PCMC) or without (rats with PCM) oral cysteine (250 mg/kg, twice daily for the fourth week) for 4 weeks. After intravenous administration to rats with PCMC, some pharmacokinetic parameters restored fully or more than the level of control rats; the time-averaged nonrenal clearance (2.70 versus 2.32 ml/min/kg) and apparent volume of distribution at steady state (160 versus 189 ml/kg) were comparable to those in control rats, however, the terminal half-life (34.7 versus 57.2 min) and mean residence time (73.3 versus 99.3 min) were significantly shorter, area under the plasma concentration-time curve from time zero to time infinity (AUC, 1930 versus 2680 microg min/ml) was significantly smaller, and time-averaged renal (2.24 versus 1.21 ml/min/kg) and total body (CL, 4.98 versus 3.65 ml/min/kg) clearances were significantly faster than those in control rats. This could be mainly due to significantly faster renal clearance and at least partly due to increased cytochrome P450 1A2 activity by cysteine supplementation. After intravenous administration to rats with PCMC, the total amount of 8-hr urinary excretion of unchanged azosemide was significantly greater (457 versus 305 microg/g body weight), however, the 8-hr urine output (15.3 versus 31.1 ml/g kidney) was not significantly different between control rats and rats with PCMC. This could be due to the fact that urine output seemed to reach an upper plateau from 10 mg/kg dose of azosemide in rats.

Bioequivalence of two aceclofenac tablet formulations after a single oral dose to healthy male Korean volunteers

A bioequivalence study of aceclofenac tablets (test formulation: Dong-A, reference formulation: Airtal) was conducted in 16 healthy male Korean volunteers who received each medicine at a dose of 100 mg in a 2 x 2 crossover study. There was a one-week washout period between the doses. Plasma concentrations of aceclofenac were monitored by high-performance liquid chromatography over a period of 24 hours after the administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated by the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf and Cmax, and non-transformed tmax. There were no significant differences between the medications in AUCinf and Cmax. The point estimates and 90% confidence intervals for AUCinf (parametric) and Cmax (parametric) were 1.04 (0.93 to approximately 1.17) and 0.99 (0.91 to approximately 1.08), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value for tmax was 0.75 (0.00 to approximately 1.00). Moreover, the modified Pitman-Morgan's adjusted F-test indicated that the bioavailabilities of aceclofenac in the 2 medications were comparable regarding intra- and interindividual variability. Therefore, these results indicate that the 2 medications of aceclofenac are bioequivalent and, thus, may be prescribed interchangeably.

Factors influencing the protein binding of a new phosphodiesterase V inhibitor, DA-8159, using an equilibrium dialysis technique

Various factors influencing the protein binding of DA-8159 to 4% human serum albumin (HSA) were evaluated using an equilibrium dialysis technique at an initial DA-8159 concentration of 5 microg/mL. It took approximately 8 h incubation to reach an equilibrium between 4% HSA and an isotonic phosphate buffer of pH 7.4 containing 3% of dextran ('the buffer') using a Spectra/Por 2 membrane (mol. wt. cut-off: 12,000--14,000) in a water bath shaker kept at 37 degrees C and at a rate of 50 oscillations per min. The extent of binding was dependent on DA-8159 concentrations, HSA concentrations, incubation temperature, buffer pH, and alpha-1-acid glycoprotein (AAG) concentrations. The binding of DA-8159 in heparinized human plasma (93.9%) was significantly higher than in rats (81.4%), rabbits (80.4%), and dogs (82.2%), and this could be due to differences in AAG concentrations in plasma.

Bioequivalence assessment of closerin capsule to dura seromycin capsule of cycloserine after a single oral dose administration to healthy male volunteers

AIM

A bioequivalence study of the closerin capsules to the dura seromycin capsules was conducted.

PATIENTS AND METHODS

Twenty-four healthy male Korean volunteers received each medicine at the cycloserine dose of 250 mg in a 2 x 2 crossover study. There was a one-week washout period between the doses. Plasma concentrations of cycloserine were monitored by a high-performance liquid chromatography for over a period of 72 hours after the administration. AUCinf (the area under the plasma concentration-time curve from time zero to time infinity) was calculated by the linear-log trapezoidal method. Cmax (maximum plasma drug concentration) and Tmax (time to reach Cmax) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed AUCinf and Cmax, and untransformed Tmax.

RESULTS

There were no significant differences between the medications in AUCinf and Cmax. The point estimates and 90% confidence intervals for AUCinf (parametric) and Cmax (parametric) were, in point estimate (90% confidence interval), 0.992 (0.950 approximately 1.037) and 1.051 (0.965 approximatly 1.144), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. The corresponding value of Tmax was 0.000 (-0.250 approximatly 0.125). Moreover, the modified Pitman-Morgan's adjusted F test and equal variance test (one-sided) indicated that the 2 medications were comparable in intra- and inter-individual variability in cycloserine bioavailability.

CONCLUSION

Therefore, these results indicate that the 2 medications of cycloserine are bioequivalent and, thus, may be prescribed interchangeably.

Effects of cysteine on the pharmacokinetics of intravenous adriamycin in rats with protein-calorie malnutrition

In rats with protein-calorie malnutrition (PCM, 5% caseine diet for 4 weeks), hepatic cytochrome P450 levels suppressed markedly and cytochrome P450 mRNAs decreased significantly compared with those in control rats (23% caseine diet for 4 weeks), however, the values completely (or partially) returned to control levels by a week (from fourth week) of cysteine supplementation (rats with PCMC) (Cho, Kim et al., Arch. Biochem. Biophys. 1999, 372: 150-158). The formation of aglycone metabolites of adriamycin and adriamycinol, M3 and M4, respectively, seemed to be induced (Lee and Lee, Res. Commun. Mol. Pathol. Pharmacol. 1999, 105: 87-96) by pretreatment with dexamethasone (possibly by hepatic cytochrome P450 RL 33/cDEX, Komori and Oda, J. Biochem. 1994, 116: 114-120) in rats. Adriamycin, 16 mg/kg, was administered intravenously in 1-min to control rats and rats with PCM and PCMC. In rats with PCM, the plasma concentrations of adriamycin was higher (the area under the plasma concentration-time curve from time zero to 12 hr, AUC(0-12 hr), tended to be higher) and 24-hr urinary excretion of M3 (including its 'conjugates') seemed to increase than those in control rats, suggested that the formation of M3 was inhibited in rats with PCM. In rats with PCMC, the plasma concentrations of adriamycin were lower (the AUC(0-12 hr) was significantly smaller) and 24-hr urinary excretion of M3 (including its 'conjugates') were significantly greater than those in rats with PCM, suggested that the formation of M3 increased significantly by cysteine supplementation by restoring the enzyme system(s) that metabolize adriamycin to M3. The altered pharmacokinetic parameters of adriamycin mentioned above in rats with PCM returned to greater than those of control rats after cysteine supplementation (rats with PCMC). Above data suggested that other hepatic cytochrome P450 isozyme(s) which catalyze(s) the formation of M3 from adriamycin could be induced by cysteine supplementation.

Effects of cilastatin on the pharmacokinetics of a new carbapenem, DA-1131, in rats, rabbits, and dogs

DA-1131, a new carbapenem antibiotic, undergoes renal metabolism by renal dehydropeptidase I (DHP-I), located on the brush border of the proximal tubular cell. Species differences with regard to the effects of cilastatin, a renal DHP-I inhibitor, were investigated after a 1-min intravenous infusion of DA-1131, with or without cilastatin, to rats, rabbits, and dogs. After intravenous infusion, the nonrenal clearance (CL(NR)) of DA-1131 was significantly slower in rats (3.00 versus 8.01 ml/min/kg) and rabbits (2.41 versus 6.77 ml/min/kg) when the drug was coadministered with cilastatin; this could be due to the slower metabolism of DA-1131 by rat and rabbit kidney DHP-I. This indicated that renal metabolism of DA-1131 by renal DHP-I was inhibited by cilastatin. However, coadministration with cilastatin to dogs did not affect the CL(NR) of DA-1131.

Mucous gland adenoma of the bronchus: CT findings in two patients

Mucous gland adenoma of the bronchus is a truly benign, well defined, intraluminal mass that manifests on CT with air-meniscus sign or abutting the bronchus. We report the CT findings of mucous gland adenoma in two patients.

Echocardiographic and morphologic characteristics of left atrial myxoma and their relation to systemic embolism

We examined the relation between the echocardiographic morphology of cardiac myxoma and systemic embolism in 25 patients. Two distinct types of myxoma could be identified by echocardiography: round type characterized by solid and round shape with nonmobile surface (n = 13, 52%), and polypoid type characterized by soft and irregular shape with mobile surface (n = 12, 48%); multiple regression analysis revealed the polypoid type of tumor was the only independent predictor of systemic embolism (p = 0.0029).

Nephroprotective effect of betamipron on a new carbapenem, DA-1131, in rabbits

The nephroprotective effect of betamipron (200 mg/kg) was evaluated after intravenous administration of a high dose of DA-1131 (200 mg/kg) to rabbits. Extensive tubular necrosis was observed without betamipron but the necrosis was not observed with betamipron at 8 h after intravenous administration of DA-1131 based on kidney microscopy. By treatment with betamipron, the amounts and tissue to plasma (T/P) ratios of DA-1131 in renal cortex and whole kidney decreased significantly (65-91% decrease) at both 30 min and 2 h after intravenous administration of the drug to rabbits. This indicated that the accumulation of DA-1131 in rabbit renal cortex and whole kidney was inhibited by betamipron. This resulted in significantly greater percentages of intravenous DA-1131 excreted in urine as unchanged drug, 60.9 versus 40.1%, and significantly faster renal clearance (Cl(r)) of DA-1131 (6.10 versus 3.22 mL/min/kg) by treatment with betamipron. By treatment with betamipron, the amounts and T/P ratios of DA-1131 in renal cortex and whole kidney decreased significantly from 30 min and the renal function remained intact at 8 h after intravenous administration of DA-1131. The above data suggested that the nephroprotective effect of betamipron was fast and persisted for a long period of time in rabbits.

Pharmacokinetics and tissue distribution of a new carbapenem DA-1131, after intravenous administration to mice, rats, rabbits and dogs

The pharmacokinetic parameters including tissue distribution and/or biliary excretion of DA-1131, a new carbapenem, were evaluated after intravenous (iv) administration to mice, rats, rabbits, and dogs. After i.v. administration to mice (20, 50, 100, and 200 mg kg-1), rats (50, 100, 200, and 500 mg kg-1), rabbits (20, 50, 100, and 200 mg kg-1), and dogs (10, 20, 50, 100, and 200 mg kg-1), the pharmacokinetic parameters of DA-1131 seemed to be independent of DA-1131 doses studied in all four animal species. However, the renal clearance of percentage of i.v. dose of DA-1131 excreted in 24 h urine as unchanged drug decreased significantly in rabbits (from 200 mg kg-1) and dogs (from 100 mg kg-1) due to reduced kidney function induced by DA-1131. The creatinine clearance decreased significantly in rabbits at 200 mg kg-1 compared with that in the control rabbits (0.466 versus 4.31 mL min-1 kg-1). Renal active secretion of DA-1131 was observed in rabbits and was less considerable in rats, but renal active reabsorption of DA-1131 was observed in dogs. Although DA-1131 was widely distributed in all tissues studied in mice (20-200 mg kg-1), rats (200 mg kg-1), rabbits (50 mg kg-1), and dogs (50 mg kg-1) affinity of DA-1131 for tissues was low: the tissue-to-plasma concentration ratios were greater than unity only in the kidney and/or liver. The low affinity of DA-1131 for tissues was also supported by relatively low values of the apparent volume of distribution at steady state in rats (147-187 mL kg-1), rabbits (91.7-148 mL kg-1), and dogs 243-298 mL kg-1). The contribution of biliary excretion of unchanged DA-1131 to nonrenal clearance of DA-1131 seemed to be minor in rats (200 mg kg-1) and dogs (50 mg kg-1); the percentages of i.v. dose excreted in 8 h bile as unchanged DA-1131 were 1.76 and 2.71% after i.v. administration of the drug to rats and dogs, respectively.

Pharmacokinetic changes of M1, M2, M3 and M4 after intravenous administration of a new anthracycline, DA-125, to rats pretreated with phenobarbital, 3-methylcholanthrene, chloramphenicol, or SKF-525A

The pharmacokinetics of M1-M4, the metabolites of a new anthracycline antineoplastic agent, DA-125, were compared after intravenous (i.v.) administration of DA-125, 15 mg kg-1, to rats pretreated with enzyme inducers, such as phenobarbital (PBT, n = 14) and 3-methylcholanthrene (MCT, n = 15), or enzyme inhibitors, such as SKF-525A (SKT, n = 11) and chloramphenicol (CMT, n = 15), and to their control rats (n = 15 for PBC, CMC or SKC, and n = 11 for MCC). After i.v. administration of DA-125, the plasma concentrations of both M1 and M2 declined slowly from 1 to 2 h onwards to 8 h in all groups of rats due to the continuous formation of M2 from M1. The AUC0-8 h of M1 (47.1 versus 7.85 micrograms min mL-1) and M2 (20.7 versus 44.3 micrograms min mL-1) decreased significantly in the PBT group compared to those in the PBC group. However, the corresponding value of only M1 (74.6 versus 89.9 micrograms min mL-1) decreased significantly in the MCT group. The above data indicate that metabolism of M1 is increased by pretreatment with both PB and 3-MC, and that of M2 with PB, but not with 3-MC. The AUC0-8 h of both M1 (126 versus 78.5 micrograms min mL-1) and M2 (69.2 versus 44.3 micrograms min mL-1) increased significantly in the SKT group compared to the SKC group. However, the corresponding values were not significantly different between CMC and CMT groups. The above data indicate that the metabolism of both M1 and M2 is inhibited by pretreatment with SKF-525A, but not with CM.