Evaluation of Drug Blood-Brain-Barrier Permeability Using a Microfluidic Chip

The blood-brain-barrier (BBB) is made up of blood vessels whose permeability enables the passage of some compounds. A predictive model of BBB permeability is important in the early stages of drug development. The predicted BBB permeabilities of drugs have been confirmed using a variety of in vitro methods to reduce the quantities of drug candidates needed in preclinical and clinical trials. Most prior studies have relied on animal or cell-culture models, which do not fully recapitulate the human BBB. The development of microfluidic models of human-derived BBB cells could address this issue. We analyzed a model for predicting BBB permeability using the Emulate BBB-on-a-chip machine. Ten compounds were evaluated, and their permeabilities were estimated. Our study demonstrated that the permeability trends of ten compounds in our microfluidic-based system resembled those observed in previous animal and cell-based experiments. Furthermore, we established a general correlation between the partition coefficient (Kp) and the apparent permeability (Papp). In conclusion, we introduced a new paradigm for predicting BBB permeability using microfluidic-based systems.

Common femoral arterial access and arteriography in infants: Principles, pearls, and pitfalls

Infant femoral arterial access is an essential part of interventional procedures, hemodynamic monitoring, and support of critically ill patients. Due to small luminal diameter, superficial location, mobility, and increased risk of vasospasm, dissection, and thrombosis, femoral artery access in the infant is a technically demanding procedure. The purpose of this manuscript is to describe an approach to successful common femoral arterial access and arteriography in infants including common pearls and pitfalls.

Successive development of ischemic malignant strokes in a patient with multiple fusiform aneurysms: A case report

BACKGROUND

Intracranial fusiform aneurysms are rare, spindle-shaped, and nonsaccular arterial dilatations that may be caused by dissection.

CASE SUMMARY

A 48-year-old man complained of wake-up onset of dysarthria and left-sided weakness. Diffusion-weighted magnetic resonance imaging of the brain revealed an infarction in the territories of the right middle and posterior cerebral arteries. Computed tomography angiography showed fusiform aneurysms in the right vertebral artery and bilateral petrous segments of the internal carotid arteries (ICAs). Despite conservative management, malignant ischemic stroke recurred in the contralateral ICA territory within a day of the onset of the index stroke.

CONCLUSION

We report a rare case of successive malignant strokes in a patient with multiple fusiform aneurysms. Herein, we emphasize that clinicians should consider aggressive treatment for patients with ischemic stroke and multiple fusiform aneurysms.

Synthesis and biological evaluation of xanthine derivatives with phenacyl group as tryptophan hydroxylase 1 (TPH1) inhibitors for obesity and fatty liver disease

Tryptophan hydroxylase 1 (TPH1) has emerged as a target for the treatment of metabolic diseases including obesity and fatty liver disease. A series of xanthine derivatives were synthesized and evaluated for their TPH1 inhibition. Among the synthesized compounds, compound 40 showed good in vitro activity and liver microsomal stability. Docking studies revealed that compound 40 showed better binding to TPH1 via key intermolecular interactions involving the xanthine scaffold, imidazo-thiazolyl ring, and hydroxyl-containing phenacyl moiety. In addition, compound 40 effectively suppressed the adipocyte differentiation of 3 T3-L1 cells.

Lesion Detection Through MRI Postprocessing in Pathology-Proven Focal Cortical Dysplasia: Experience at a Single Institution in the Republic of Korea

BACKGROUND AND PURPOSE

Focal cortical dysplasia (FCD) is one of the most common causes of drug-resistant epilepsy, and necessitates a multimodal evaluation to ensure optimal surgical treatment. This study aimed to determine the supportive value of the morphometric analysis program (MAP) in detecting FCD using data from a single institution in Korea.

METHODS

To develop a standard reference for the MAP, normal-looking MRIs by two scanners that are frequently used in this center were chosen. Patients with drug-resistant epilepsy and FCD after surgery were candidates for the analysis. The three-dimensional T1-weighted MRI scans of the patients were analyzed as test cases using the MAP.

RESULTS

The MRI scans of 87 patients were included in the analysis. The radiologist detected abnormal findings correlated with FCD (RAD positive [RAD(+)]) in 34 cases (39.1%), while the MAP could detect FCD in 25.3% of cases. A combination of the MAP (MAP[+] cases) with interpretations by the radiologist increased the detection to 42.5% (37 cases). The lesion detection rate was not different according to the type of reference scanners except in one case. MAP(+)/RAD(-) presented in three cases, all of which had FCD type IIa. The detection rate was slightly higher using the same kind of scanner as a reference, but not significantly (35.0% vs. 22.4% p=0.26).

CONCLUSIONS

The results of postprocessing in the MAP for detecting FCD did not depend on the type of reference scanner, and the MAP was the strongest in detecting FCD IIa. We suggested that the MAP could be widely utilized without developing institutional standards and could become an effective tool for detecting FCD lesions.

Interplay among Conformation, Intramolecular Hydrogen Bonds, and Chameleonicity in the Membrane Permeability and Cyclophilin A Binding of Macrocyclic Peptide Cyclosporin O Derivatives

A macrocyclic peptide scaffold with well-established structure-property relationship is desirable for tackling undruggable targets. Here, we adopted a natural macrocycle, cyclosporin O (CsO) and its derivatives (CP1-3), and evaluated the impact of conformation on membrane permeability, cyclophilin A (CypA) binding, and the pharmacokinetic (PK) profile. In nonpolar media, CsO showed a similar conformation to cyclosporin A (CsA), a well-known chameleonic macrocycle, but less chameleonic behavior in a polar environment. The weak chameleonicity of CsO resulted in decreased membrane permeability; however, the more rigid conformation of CsO was not detrimental to its PK profile. CsO exhibited a higher plasma concentration than CsA, which resulted from minimal CypA binding and lower accumulation in red blood cells and moderate oral bioavailability (F = 12%). Our study aids understanding of CsO, a macrocyclic peptide that is less explored than CsA but with greater potential for diversity generation and rational design.

Neurochemical Effects of 4-(2Chloro-4-Fluorobenzyl)-3-(2-Thienyl)-1,2,4-Oxadiazol-5(4H)-One in the Pentylenetetrazole (PTZ)-Induced Epileptic Seizure Zebrafish Model

Epilepsy is one of the most common neurological disorders, and it is characterized by spontaneous seizures. In a previous study, we identified 4-(2-chloro-4-fluorobenzyl)-3-(2-thienyl)-1,2,4-oxadiazol-5(4H)-one (GM-90432) as a novel anti-epileptic agent in chemically- or genetically-induced epileptic zebrafish and mouse models. In this study, we investigated the anti-epileptic effects of GM-90432 through neurochemical profiling-based approach to understand the neuroprotective mechanism in a pentylenetetrazole (PTZ)-induced epileptic seizure zebrafish model. GM-90432 effectively improved PTZ-induced epileptic behaviors via upregulation of 5-hydroxytryptamine, 17-β-estradiol, dihydrotestosterone, progesterone, 5α -dihydroprogesterone, and allopregnanolone levels, and downregulation of normetanephrine, gamma-aminobutyric acid, and cortisol levels in brain tissue. GM-90432 also had a protective effect against PTZ-induced oxidative stress and zebrafish death, suggesting that it exhibits biphasic neuroprotective effects via scavenging of reactive oxygen species and anti-epileptic activities in a zebrafish model. In conclusion, our results suggest that neurochemical profiling study could be used to better understand of anti-epileptic mechanism of GM-90432, potentially leading to new drug discovery and development of anti-seizure agents.

Efficacy and pharmacokinetics evaluation of 4-(2-chloro-4-fluorobenzyl)-3-(2-thienyl)-1,2,4-oxadiazol-5(4H)-one (GM-90432) as an anti-seizure agent

Epilepsy is a common chronic neurological disease characterized by recurrent epileptic seizures. A seizure is an uncontrolled electrical activity in the brain that can cause different levels of behavior, emotion, and consciousness. One-third of patients fail to receive sufficient seizure control, even though more than fifty FDA-approved anti-seizure drugs (ASDs) are available. In this study, we attempted small molecule screening to identify potential therapeutic agents for the treatment of seizures using seizure-induced animal models. Through behavioral phenotype-based screening, 4-(2-chloro-4-fluorobenzyl)-3-(2-thienyl)-1,2,4-oxadiazol-5(4H)-one (GM-90432) was identified as a prototype. GM-90432 treatment effectively decreased seizure-like behaviors in zebrafish and mice with chemically induced seizures. These results were consistent with decreased neuronal activity through immunohistochemistry for pERK in zebrafish larvae. Additionally, electroencephalogram (EEG) analysis revealed that GM-90432 decreases seizure-specific EEG events in adult zebrafish. Moreover, we revealed the preferential binding of GM-90432 to voltage-gated Na⁺ channels using a whole-cell patch clamp technique. Through pharmacokinetic analysis, GM-90432 effectively penetrated the blood-brain barrier and was distributed into the brain. Taken together, we suggest that GM-90432 has the potential to be developed into a new ASD candidate.

Identification of new arylsulfide derivatives as anti-melanogenic agents in a zebrafish model

A series of aryl sulfide derivatives was synthesized and evaluated for their anti-melanogenic activities. Several compounds, including 3e, 3i and 3q exhibited good anti-melanogenic activities. Among the derivatives, compound 3i showed good inhibitory effects against melanin synthesis and showed no toxicity in reconstituted human eye and skin tissues.

Neurochemical and behavioral analysis by acute exposure to bisphenol A in zebrafish larvae model

Bisphenol A (BPA) is a chemical monomer widely used in the production of hard plastics for food containers and personal items. Through improper industrial control and disposal, BPA has become a pervasive environmental contaminant, and toxicological studies have shown potent xenobiotic endocrine disruptor activity. Prenatal exposure in particular can lead to infertility and nervous system disorders characterized by behavioral aggression, depression, and cognitive impairment, thus necessitating careful hazard assessment. In this study, we evaluated BPA accumulation rate, blood-brain barrier (BBB) permeability, lethality, cardiotoxicity, behavioral effects, and impacts on multiple neurochemical pathways in zebrafish larvae. The bioconcentration factor (BCF) ranged from 1.95 to 10.0, resulting in a high rate of accumulation in the larval body. Also, high BBB permeability allowed BPA to accumulate at similar rates in both zebrafish and adult mouse (blood to brain concentration ratios of 3.2-6.7 and 1.8 to 5.5, respectively). In addition, BPA-exposed zebrafish larvae exhibited developmental deformities, reduced heart rate, and impaired behavioral patterns, including decreased total distance traveled, slower movement velocity, and altered color-preference. These impairments were associated with inhibition of the phenylalanine to dopamine synthesis pathway and an imbalance between excitatory and inhibitory neurotransmitter systems. Our results suggest that behavioral alteration in BPA-exposed zebrafish result from high accumulation and ensuing dysregulation of serotonergic, kynurenergic, dopaminergic, cholinergic, and GABAergic neurotransmitter systems. In conclusion, similarities in toxic responses to mammalian models highlight the utility of the zebrafish larva as a convenient model for screening environmental toxins.

Semi-automatic segmentation and surface reconstruction of computed tomography images by using rotoscoping and warping techniques

BACKGROUND

Quick and large-scale segmentation along with three-dimensional (3D) reconstruction is necessary to make precise 3D musculoskeletal models for surface anatomy education, palpation training, medical communication, morphology research, and virtual surgery simulation. However, automatic segmentation of the skin and muscles remain undeveloped.

MATERIALS AND METHODS

Therefore, in this study, we developed workflows for semi-automatic segmentation and surface reconstruction, using rotoscoping and warping techniques.

RESULTS

The techniques were applied to multi detector computed tomography images, which were optimised to quickly generate surface models of the skin and the anatomical structures underlying the fat tissue.

CONCLUSIONS

The workflows developed in this study are expected to enable researchers to create segmented images and optimised surface models from any set of serially sectioned images quickly and conveniently. Moreover, these optimised surface models can easily be modified for further application or educational use.

Anti-inflammatory effect of a novel synthetic compound 1-((4-fluorophenyl)thio)isoquinoline in RAW264.7 macrophages and a zebrafish model

The compound, 1-((4-fluorophenyl)thio)isoquinoline (FPTQ), is a synthetic isoquinoline derivative. To test the anti-inflammatory effect of FPTQ, we used neutrophil-specific transgenic zebrafish Tg(mpx::EGFP)ⁱ¹¹⁴ line and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. We also used two different methods, involving tail transection and LPS stimulation in the zebrafish model. Neutrophils translocation in the zebrafish tail-transected model was inhibited by FPTQ. Neutrophil aggregation was also inhibited by FPTQ in the LPS-stimulated zebrafish model. Decreased mRNA expression of the pro-inflammatory cytokine genes, interleukin-1β (il-1β) and interleukin-6 (il-6), was found in zebrafish larvae injected with FPTQ. Additionally, production of nitric oxide was inhibited by FPTQ in RAW264.7 macrophage cells treated with LPS. Moreover, the mRNA expression of Il-1β and Il-6 suppressed by FPTQ treatment in RAW264.7 macrophage cells, and an enzyme immunoassay showed that FPTQ suppressed the secretion of IL-1β and IL-6 in RAW264.7 cells. These results demonstrate that FPTQ reduced inflammatory responses and, therefore, suggest that it may be effective as an anti-inflammatory agent.

Periodic Limb Movements During Sleep Are Not Associated With Hypertension in a Clinical Cohort of Korean Adults

BACKGROUND

There is growing evidence of increased cardiovascular risk including hypertension in patients with periodic limb movements during sleep (PLMS). In a multiethnic cohort study, the association between prevalent hypertension and PLMS varied according to ethnicity. We evaluated whether PLMS are associated with hypertension in Koreans.

METHODS

We enrolled 1,163 subjects who had polysomnography (PSG) from 2 tertiary hospitals. All subjects completed a sleep questionnaire before the PSG study. Coincidental hypertension was recorded according to past medical history. We analyzed the association between periodic limb movement index (PLMI), periodic limb movement associated with arousal index (PLMAI), and coincidental hypertension. Covariates were age, sex, body mass index (BMI), restless legs syndrome, apnea-hypopnea index (AHI), arousal index, and average oxygen saturation.

RESULTS

A total of 304 subjects (26.1%) had hypertension. The proportion of subjects with hypertension in the PLMI ≥ 15 category was higher than that in the PLMI < 15 category (32.4% vs. 25.0%; P = 0.04). The proportion of subjects with hypertension in the PLMAI ≥ 1 category was 32.6%, which was higher than that in the PLMAI < 1 category (24.6%; P = 0.02). In a multivariate regression model, neither PLMI (odds ratio [OR], 1.12; 95% confidence interval [CI] 0.75-1.68) nor PLMAI (OR, 1.21; 95% CI 0.83-1.76) were associated with hypertension. Statistical significance was found between coincidental hypertension and the following variables: age, smoking history, BMI, and AHI.

CONCLUSIONS

In a retrospective hospital-based study, there was no association between coincidental hypertension and PLMI/PLMAI in Koreans.

Quantitative Evaluation of Cytochrome P450 3A4 Inhibition and Hepatotoxicity in HepaRG 3-D Spheroids

Predicting drug–drug interactions (DDIs) is an important step during drug development to avoid unexpected side effects. Cytochrome P450 (CYP) 3A4 is the most abundant human hepatic phase I enzyme, which metabolizes >50% of therapeutic drugs. Therefore, it is essential to test the potential of a drug candidate to induce CYP3A4 expression or inhibit its activity. Recently, 3-dimensional (3-D) mammalian cell culture models have been adopted in drug discovery research to assess toxicity, DDIs, and pharmacokinetics. In this study, we applied a human 3-D spheroid culture protocol using HepaRG cells combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to assess its ability to predict CYP3A4 inhibition. Levels of midazolam, a specific substrate of CYP3A4, were used to determine the long-term metabolic capacity of CYP3A4. Midazolam was decreased in the 3-D HepaRG culture system by ∼80% over 7 days, whereas its primary metabolite, 1-hydroxymidazolam, increased by ∼40%. Next, we assessed hepatotoxicity by determining the cytotoxicity of known hepatotoxicants in HepaRG spheroids, HepG2 cells, and primary human hepatocytes. Significant differences in cytotoxicity were detected in the system using 3-D HepaRG spheroids. These results suggest that 3-D HepaRG spheroids are a good model for prediction of CYP inhibition and hepatotoxicity in screening of early drug candidates.

A novel anti-melanogenic agent, KDZ-001, inhibits tyrosinase enzymatic activity

BACKGROUND

The demand for anti-melanogenic agents is increasing due to the unwanted side effects of current treatments. To find an effective anti-melanogenic agent, we used zebrafish as a whole animal model for phenotype-based drug and cosmetic discovery screening.

OBJECTIVES

The aim of this study was to identify and explore a small molecule that could be used for skin-whitening cosmetics.

METHODS

Using zebrafish embryos, we examined the effects of 1000 compounds on zebrafish development and pigmentation. Pigmentation production was assessed by tyrosinase (TYR) enzymatic activity and melanin contents. Pigmentation marker expression in the human melanoma cell line HMV-II was analyzed by western blot. We also tested reconstituted human skin tissue and analyzed KDZ-001 with computational molecular modeling.

RESULTS

We identified three compounds that affected the pigmentation of developing melanophores in zebrafish. Among them, we identified KDZ-001, a novel anti-melanogenic agent, which strongly inhibits melanin synthesis in the developing melanophores of zebrafish, HMV-II cells, and reconstituted human skin with no toxicity. We found that KDZ-001 directly inhibits TYR enzymatic activity. Notably, computational molecular modeling of KDZ-001 suggested that its interaction with copper ions in the active site of TYR is essential for melanin synthesis, further demonstrating that KDZ-001 mainly acts as a TYR inhibitor to synthesize melanin.

CONCLUSION

KDZ-001 inhibits melanin synthesis and has a potential for use in skin-whitening cosmetics.

Zebrafish as a Screening Model for Testing the Permeability of Blood-Brain Barrier to Small Molecules

The objective of this study was to evaluate the permeability of small molecules into the brain via the blood-brain barrier in zebrafish and to investigate the possibility of using this animal model as a screening tool during the early stages of drug discovery. Fifteen compounds were used to understand the permeation into the brain in zebrafish and mice. The ratio of brain-to-plasma concentration was compared between the two animal models. The partition coefficient (K_p,brain), estimated using the concentration ratio at designated times (0.167, 0.25, 0.5, or 2 h) after oral administrations (per os, p.o), ranged from 0.099 to 5.68 in zebrafish and from 0.080 to 11.8 in mice. A correlation was observed between the K_p,brain values obtained from the zebrafish and mice, suggesting that zebrafish can be used to estimate K_p,brain to predict drug penetration in humans. Furthermore, in vivo transport experiments to understand the permeability glycoprotein (P-gp) transporter-mediated behavior of loperamide (LPM) in zebrafish were performed. The zebrafish, K_{p,brain,30min} of LPM was determined to be 0.099 ± 0.069 after dosing with LPM alone, which increased to 0.180 ± 0.115 after dosing with LPM and tariquidar (TRQ, an inhibitor of P-gp). In mouse, the K_{p,brain,30min} of LPM was determined to be 0.080 ± 0.004 after dosing with LPM alone and 0.237 ± 0.013 after dosing with LPM and TRQ. These findings indicate that the zebrafish could be used as an effective screening tool during the discovery stages of new drugs to estimate their distribution in the brain.

Sectioned images and surface models of a cadaver for understanding the free vascularised anterior rib flap

BACKGROUND

The purpose of this study is to describe the vascularised anterior rib flap on sectioned images and surface models using Visible Korean for medical education and clinical training in the field of mandibular reconstructive surgery.

MATERIALS AND METHODS

Serially sectioned images of the thorax were obtained from a cadaver. Significant structures in the sectioned images were outlined and stacked to create a surface model.

RESULTS

The PDF file (8.45 MB) of the assembled models can be downloaded for free from our website (http://vkh.ajou.ac.kr/Products/PDF/Vascularized_anterior_rib_flap.zip). In this file, important anatomical structures related to the vascularised anterior rib flap can be examined in the sectioned images. All surface models and stereoscopic structures of the vascularised anterior rib flap are expressed in real time.

CONCLUSIONS

We hope that these state-of-the-art sectioned images, outlined images, and surface models will help students and trainees gain a better understanding of the anatomy of the vascularised anterior rib flap.

Segmentation and surface reconstruction of a cadaver heart on Mimics software

The Visible Korean research team used Mimics software (Materialise, Leuven, Belgium) for the segmentation and subsequent surface reconstruction of heart structures using information obtained from sectioned images of a cadaver. Twenty-six heart components were outlined in advance on Photoshop (Adobe Systems, San Jose, CA, USA). By use of the Mimics, the outlined images were then browsed along with the vertical planes as well as the 3-dimensional surface models, which were immediately built by piling the images. Erroneous delineation was readily detected and revised until satisfactory heart models were acquired. The surface models and the selected sectioned images in horizontal, coronal, and sagittal planes were inputted into a PDF file, where any combinations of reconstructed constituents could be displayed and rotated by the user. Mimics software accelerated the segmentation and surface reconstruction of heart anatomical structures. Similar benefits hopefully result from various serial images of other organs. The PDF file, and plane and stereoscopic image data are being distributed to others, and should prove valuable for medical students and clinicians.

Investigation of bioequivalence of a new fixed-dose combination of acarbose and metformin with the corresponding loose combination as well as the drug-drug interaction potential between both drugs in healthy adult male subjects

WHAT IS KNOWN AND OBJECTIVE

Both metformin and acarbose are recommended monotherapy and add-on therapy in type 2 diabetes mellitus (T2DM). A fixed-dose combination (FDC) of acarbose and metformin has been developed to reduce pill burden and potentially improve compliance. The current study investigated the bioequivalence of the acarbose/metformin FDC compared with the individual agents administered simultaneously (loose combination). Secondary endpoints were the safety and tolerability of the FDC and the potential for drug-drug interactions between acarbose and metformin.

METHODS

A single-centre, randomized, open-label, four-period crossover study was conducted in healthy male Korean subjects aged 18-45 years. Following one-period balanced Williams design, participants were randomized to receive four single oral treatments on different study days separated by ≥7 days' washout. Treatments were as follows: (i) acarbose/metformin 50/500 mg FDC (test); (ii) acarbose 50 mg and metformin 500 mg as loose combination (reference); (iii) acarbose 50 mg; and (iv) metformin 500 mg. Serial blood samples were taken for glucose and insulin levels for 4 h after a sucrose load on the day before and day of study drug administration. Additionally, serial blood samples were taken for analysis of metformin levels for 24 h after each drug containing metformin. The area under the curve for 4 h post-test (AUC0-4 h ) and the maximal serum concentration (Cmax ) of plasma glucose and serum insulin were primary pharmacodynamic (PD) parameters, and Cmax , AUC0-last and AUC for metformin levels were primary pharmacokinetic (PK) parameters. The bioequivalence of the FDC to the loose combination was considered established if the 90% confidence intervals (CIs) of the baseline-adjusted PD parameter ratios (test vs. reference) for plasma glucose and the PK parameter ratios for metformin fell completely within current acceptance limits (0·8-1·25).

RESULTS AND DISCUSSION

Thirty-three of 40 randomized subjects completed the study; five withdrew consent and two discontinued because of adverse events (AEs). The 24-h plasma concentration-time curves of metformin and the 4-h plasma glucose-time curves after acarbose/metformin FDC (test) and acarbose + metformin loose combination (reference) were almost superimposable. The geometric least squares (LS) mean of the RatioAUC and RatioCmax for plasma glucose after the FDC vs. loose combination, and the LS mean of the ratios in metformin AUC, AUC0-last and Cmax were close to unity, and the 90% CI of all these parameters fell within the predefined equivalence range of 0·8-1·25, confirming bioequivalence. The metformin AUC was reduced by 26% and Cmax by 34% after acarbose + metformin compared with metformin alone. Eight subjects (20·0%) reported AEs, but all were mild, and most were gastrointestinal, as expected for these agents. The incidence of AEs was not higher with the combinations vs. monotherapy.

WHAT IS NEW AND CONCLUSION

These data demonstrate that the acarbose/metformin FDC is bioequivalent to the loose combination of these agents. Although acarbose slightly reduced the bioavailability of metformin, the accumulated evidence of the efficacy of this combination implies that this is clinically irrelevant. The observed AE profile was consistent with the established knowledge on the safety of the two drugs.

Phosphatase of regenerating liver-3 promotes migration and invasion by upregulating matrix metalloproteinases-7 in human colorectal cancer cells

Phosphatase of regenerating liver (PRL)-3, a member of a subgroup of protein tyrosine phosphatases that can stimulate the degradation of the extracellular matrix, is over-expressed in metastatic colorectal cancer (CRC) relative to primary tumors. To determine whether PRL-3-induced enhancement of migration and invasion is dependent on the expression of matrix metalloproteinases (MMPs), PRL-3 was expressed in DLD-1 human CRC cells. The motility, migration and invasion characteristics of the cells were examined, and metastasis to the lung was confirmed in a nude mouse using PRL-3-overexpressing DLD-1 cells [DLD-1 (PRL-3)]. Migration and invasion of the cells were inhibited by phosphatase and farnesyltransferase inhibitors. Expression of MMPs was enhanced 3- to 10-fold in comparison to control cells, and migration and invasion were partially inhibited by small interfering RNA (siRNA) knockdown of MMP-2, -13 or -14. Importantly, siRNA knockdown of MMP-7 completely inhibited the migration and invasion of DLD-1 (PRL-3) cells, whereas overexpression of MMP-7 increased migration. The expression of MMP-7 was also downregulated by phosphatase and farnesyltransferase inhibitors. It was found that PRL-3 induced MMP-7 through oncogenic pathways including PI3K/AKT and ERK and that there is a relationship between the expression of PRL-3 and MMP-7 in human tumor cell lines. The expression of MMP-13 and -14 was very sensitive to the inhibition of farnesyltransferase; however, the migration and invasion of DLD-1 (PRL-3) cells did not strongly depend on the expression of MMP-13 or -14. These results suggest that the migration and invasion of PRL-3-expressing CRC cells depends primarily on the expression of MMP-7.

Cosmomycin C inhibits signal transducer and activator of transcription 3 (STAT3) pathways in MDA-MB-468 breast cancer cell

The signal transducer and activator of transcription 3 (STAT3) is constitutively activated in cancer cells. Therefore, blocking the aberrant activity of STAT3 in tumor cells is a validated therapeutic strategy. To discover novel inhibitors of STAT3 activity, we screened against microbial natural products using a dual-luciferase assay. Using the microbial metabolome library, we identified cosmomycin C (CosC), which was isolated from the mycelium extract of Streptomyces sp. KCTC19769, as a STAT3 pathway inhibitor. CosC inhibited STAT3 (Tyr705) phosphorylation and subsequent nuclear translocation in MDA-MB-468 breast cancer cells. CosC-mediated inhibition of STAT3 signaling pathway was confirmed by suppressed expression of STAT3 downstream target proteins including cyclin D1, Bcl-xL, survivin, Mcl-1, and VEGF in CosC-treated MDA-MB-468 cells. Flow cytometry showed that CosC caused accumulation in the G(0)-G(1) phase of the cell cycle and induced apoptosis via PARP cleavage and caspase-3 activation. Based on these findings, CosC may be a potential candidate for modulation of STAT3 pathway.

2-Hydroxycurcuminoid induces apoptosis of human tumor cells through the reactive oxygen species-mitochondria pathway

2-Hydroxycinnamaldehyde (HCA) and curcumin have been reported to have antitumor effects against various human tumor cells in vitro and in vivo by generation of ROS. Aldehyde-free HCA analogs were synthesized based on the structure of curcumin, which we have called 2-hydroxycurcuminoids. The hydroxyl group of curcuminoids enhances the ability to generate ROS. 2-Hydroxycurcuminoid (HCC-7) strongly inhibited the growth of SW620 colon tumor cells with a GI(50) value of 7μM, while the parent compounds, HCA and curcumin, displayed GI(50) values of 12 and 30μM, respectively. HCC-7 was found to induce apoptosis through the reactive oxygen species-mitochondria pathway and cell cycle arrest at G2/M phase.

KRIBB11 inhibits HSP70 synthesis through inhibition of heat shock factor 1 function by impairing the recruitment of positive transcription elongation factor b to the hsp70 promoter

Heat shock factor 1 (HSF1) is the master switch for heat shock protein (HSP) expression in eukaryotes. A synthetic chemical library was screened to identify inhibitors of HSF1 using a luciferase reporter under the control of a heat shock element. A compound named KRIBB11 (N(2)-(1H-indazole-5-yl)-N(6)-methyl-3-nitropyridine-2,6-diamine) was identified for its activity in abolishing the heat shock-induced luciferase activity with an IC(50) of 1.2 μmol/liter. When the cells were exposed to heat shock in the presence of KRIBB11, the induction of HSF1 downstream target proteins such as HSP27 and HSP70 was blocked. In addition, treatment of HCT-116 cells with KRIBB11 induced growth arrest and apoptosis. Markers of apoptosis, such as cleaved poly(ADP-ribose) polymerase, were detected after KRIBB11 treatment. Biotinyl-KRIBB11 was synthesized as an affinity probe for the identification of KRIBB11 target proteins. Using affinity chromatography and competition assays, KRIBB11 was shown to associate with HSF1 in vitro. Chromatin immunoprecipitation analysis showed that KRIBB11 inhibited HSF1-dependent recruitment of p-TEFb (positive transcription elongation factor b) to the hsp70 promoter. Finally, intraperitoneal treatment of nude mice with KRIBB11 at 50 mg/kg resulted in a 47.4% (p < 0.05) inhibition of tumor growth without body weight loss. Immunoblotting assays showed that the expression of HSP70 was lower in KRIBB11-treated tumor tissue than in control tissues. Because HSPs are expressed at high levels in a wide range of tumors, these results strengthen the rationale for targeting HSF1 in cancer therapy.

Cryptotanshinone inhibits constitutive signal transducer and activator of transcription 3 function through blocking the dimerization in DU145 prostate cancer cells

Because signal transducer and activator of transcription 3 (STAT3) is constitutively activated in most human solid tumors and is involved in the proliferation, angiogenesis, immune evasion, and antiapoptosis of cancer cells, researchers have focused on STAT3 as a target for cancer therapy. We screened for natural compounds that inhibit the activity of STAT3 using a dual-luciferase assay. Cryptotanshinone was identified as a potent STAT3 inhibitor. Cryptotanshinone rapidly inhibited STAT3 Tyr705 phosphorylation in DU145 prostate cancer cells and the growth of the cells through 96 hours of the treatment. Inhibition of STAT3 Tyr705 phosphorylation in DU145 cells decreased the expression of STAT3 downstream target proteins such as cyclin D1, survivin, and Bcl-xL. To investigate the cryptotanshinone inhibitory mechanism in DU145 cells, we analyzed proteins upstream of STAT3. Although phosphorylation of Janus-activated kinase (JAK) 2 was inhibited by 7 micromol/L cryptotanshinone at 24 hours, inhibition of STAT3 Tyr705 phosphorylation occurred within 30 minutes and the activity of the other proteins was not affected. These results suggest that inhibition of STAT3 phosphorylation is caused by a JAK2-independent mechanism, with suppression of JAK2 phosphorylation as a secondary effect of cryptotanshinone treatment. Continuing experiments revealed the possibility that cryptotanshinone might directly bind to STAT3 molecules. Cryptotanshinone was colocalized with STAT3 molecules in the cytoplasm and inhibited the formation of STAT3 dimers. Computational modeling showed that cryptotanshinone could bind to the SH2 domain of STAT3. These results suggest that cryptotanshinone is a potent anticancer agent targeting the activation STAT3 protein. It is the first report that cryptotanshinone has antitumor activity through the inhibition of STAT3.

Enhanced Ih depresses rat entopeduncular nucleus neuronal activity from high-frequency stimulation or raised Ke+

High-frequency stimulation (HFS) is used to treat a variety of neurological diseases, yet its underlying therapeutic action is not fully elucidated. Previously, we reported that HFS-induced elevation in [K(+)](e) or bath perfusion of raised K(e)(+) depressed rat entopeduncular nucleus (EP) neuronal activity via an enhancement of an ionic conductance leading to marked depolarization. Herein, we show that the hyperpolarization-activated (I(h)) channel mediates the HFS- or K(+)-induced depression of EP neuronal activity. The perfusion of an I(h) channel inhibitor, 50 microM ZD7288 or 2 mM CsCl, increased input resistance by 23.5 +/- 7% (ZD7288) or 35 +/- 10% (CsCl), hyperpolarized cells by 3.4 +/- 1.7 mV (ZD7288) or 2.3 +/- 0.9 mV (CsCl), and decreased spontaneous action potential (AP) frequency by 51.5 +/- 12.5% (ZD7288) or 80 +/- 13.5% (CsCl). The I(h) sag was absent with either treatment, suggesting a block of I(h) channel activity. Inhibition of the I(h) channel prior to HFS or 6 mM K(+) perfusion not only prevented the previously observed decrease in AP frequency, but increased neuronal activity. Under voltage-clamp conditions, I(h) currents were enhanced in the presence of 6 mM K(+). Calcium is also involved in the depression of EP neuronal activity, since its removal during raised K(e)(+) application prevented this attenuation and blocked the I(h) sag. We conclude that the enhancement of I(h) channel activity initiates the HFS- and K(+)-induced depression of EP neuronal activity. This mechanism could underlie the inhibitory effects of HFS used in deep brain stimulation in output basal ganglia nuclei.

Transition to seizures in the isolated immature mouse hippocampus: a switch from dominant phasic inhibition to dominant phasic excitation

The neural dynamics and mechanisms responsible for the transition from the interictal to the ictal state (seizures) are unresolved questions in epilepsy. It has been suggested that a shift from inhibitory to excitatory GABAergic drive can promote seizure generation. In this study, we utilized an experimental model of temporal lobe epilepsy which produces recurrent seizure-like events in the isolated immature mouse hippocampus (P8-16), perfused with low magnesium ACSF, to investigate the cellular dynamics of seizure transition. Whole-cell and perforated patch recordings from CA1 pyramidal cells and from fast- and non-fast-spiking interneurons in the CA1 stratum oriens hippocampal region showed a change in intracellular signal integration during the transition period, starting with dominant phasic inhibitory synaptic input, followed by dominant phasic excitation prior to a seizure. Efflux of bicarbonate ions through the GABA A receptor did not fully account for this excitation and GABAergic excitation via reversed IPSPs was also excluded as the prime mechanism generating the dominant excitation, since somatic and dendritic GABA A responses to externally applied muscimol remained hyperpolarizing throughout the transition period. In addition, abolishing EPSPs in a single neuron by intracellularly injected QX222, revealed that inhibitory synaptic drive was maintained throughout the entire transition period. We suggest that rather than a major shift from inhibitory to excitatory GABAergic drive prior to seizure onset, there is a change in the interaction between afferent synaptic inhibition, and afferent and intrinsic excitatory processes in pyramidal neurons and interneurons, with maintained inhibition and increasing, entrained 'overpowering' excitation during the transition to seizure.

Synthesis and biological evaluation of cinnamyl compounds as potent antitumor agents

A series of cinnamyl compounds related to 2'-hydroxycinnamaldehyde were synthesized and their antitumor effects against human cancer cells evaluated. Hydroxylamine derivative 6 inhibited the growth of human cancer cells and human colon tumor xenograft in nude mice. Its antitumor effects belong to the induction of apoptosis and arresting cell cycle at G(2)/M phase, which is confirmed by detection of apoptosis markers and cell cycle analysis.

Apoptosis induction of 2′-hydroxycinnamaldehyde as a proteasome inhibitor is associated with ER stress and mitochondrial perturbation in cancer cells

2'-Hydroxycinnamaldehyde (HCA), isolated from the stem bark of Cinnamomum cassia, and 2'-benzoyloxycinnamaldehyde (BCA), one of HCA derivatives, have antiproliferative activities on several human cancer cell lines. Our previous study suggested that reactive oxygen species (ROS) and caspase-3 are the major regulators of HCA-induced apoptosis. In the present study, we demonstrated a novel molecular target using in vitro pull-down assay by biotin-labeled HCA (biotin-HCA) in SW620 cells. We analyzed 11 differential spots of 2-dimensional gel prepared with pull-downed proteins by biotin-HCA. Among them, five spots were identified as proteasome subunits. An in vitro 26S proteasome function assay using specific fluorogenic substrates showed that HCA potently inhibits L3-like activity of the proteasome. In addition, HCA showed inhibitory action against chymotrypsin-like, trypsin-like, and PGPH-like activities. DNA microarray showed that HCA induced heat shock family and ER stress-responsive genes, which reflects the accumulation of misfolded proteins by proteasome inhibition. On western blot analysis, it was confirmed that HCA induces glucose-regulated protein, 78 kDa (GRP78) and some representative endoplasmic reticulum (ER) stress-responsive proteins. Furthermore, HCA treatment decreased mitochondrial membrane potential. The effect of HCA on cytochrome c and Bax translocation between cytosol and mitochondrial membrane was clarified using western blot analysis. These results suggest that HCA-induced apoptosis is associated with the inhibition of the proteasome activity that leads in turn to the increase of ER stress and mitochondrial perturbation.

High frequency stimulation or elevated K+ depresses neuronal activity in the rat entopeduncular nucleus

High frequency stimulation (HFS) is applied to many brain regions to treat a variety of neurological disorders/diseases, yet the mechanism(s) underlying its effects remains unclear. While some studies showed that HFS inhibits the stimulated nucleus, others report excitation. In this in vitro study, we stimulated the rat globus pallidus interna (entopeduncular nucleus, EP), a commonly stimulated area for Parkinson's disease, to investigate the effect of HFS-induced elevation of extracellular potassium (K(+)(e)) on rat EP neuronal activity. Whole-cell patch-clamp recordings and [K(+)](e) measurements were obtained in rat EP brain slices before, during and after HFS. After HFS (150 Hz, 10 s), [K(+)](e) increased from 2.5-9.6+/-1.4 mM, the resting membrane potential of EP neurons depolarized by 11.1+/-2.5 mV, spiking activity was significantly depressed, and input resistance decreased by 25+/-6%. The GABA(A) receptor blocker, gabazine, did not prevent these effects. The bath perfusion of 6 or 10 mM K(+), with or without synaptic blockers, mimicked the HFS-mediated effects: inhibition of spike activity, a 20+/-9% decrease in input resistance and a 17.4+/-3.0 mV depolarization. This depolarization exceeded predicted values of elevated [K(+)](e) on the resting membrane potential. A depolarization block did not fully account for the K(+)-induced inhibition of EP neuronal activity. Taken together, our results show that HFS-induced elevation of [K(+)](e) decreased EP neuronal activity by the activation of an ion conductance resulting in membrane depolarization, independent of synaptic involvement. These findings could explain the inhibitory effects of HFS on neurons of the stimulated nucleus.

Synthesis and biological evaluation of dimeric cinnamaldehydes as potent antitumor agents

It has been reported that 2-hydroxycinnamaldehyde and 2-benzoyl-oxycinnamaldehyde inhibited the activity of farnesyl protein transferase, angiogenesis, cell-cell adhesion, and tumor growth in vivo model. In order to improve its anti-tumor activity, dimeric cinnamaldehydes have been synthesized based on 2-hydroxycinnamaldehyde. The synthesized compounds strongly inhibited the growth of human colon tumor cells with GI50 values of 0.6-10 microM. Especially, 2-piperazine derivative blocked in vivo growth of human colon tumor xenograft in nude mice at 10 mg/kg. It was found that their anti-tumor effects induce apoptosis and cell cycle arrest at G2/M phase by the compounds. It was confirmed by detection of apoptosis markers such as activated caspase-3 and cleaved PARP, and cell cycle analysis. The dimeric compounds also inhibited Cdc25B phosphatase which is essential for preinitiating G2/M transition and S phase progression.

Dehydrotrametenolic acid selectively inhibits the growth of H-ras transformed rat2 cells and induces apoptosis through caspase-3 pathway

The screening of natural products that preferentially inhibit growth of H-ras transformed rat2 cells vs. rat2 cells was performed to identify H-ras specific growth inhibitor. A lanostane-type triterpene acid, dehydrotrametenolic acid (3beta-hydroxylanosta-7,9(11),24-trien-21-oic acid), was isolated from the sclerotium of Poria cocos (Polyporaceae). Dehydrotrametenolic acid selectively inhibited the growth of H-ras transformed cells with a GI(50) value of 40 microM. FACS analysis indicated that the compound exerted its anti-proliferation effects through cell cycle arrest at G2/M phase and accumulation of sub-G1 population. Dehydrotrametenolic acid-induced apoptosis was further confirmed with chromosomal DNA fragmentation, caspase-3 activation, and degradation of PARP and Lamin A/C degradation. The compound also regulated the expression of H-ras, Akt and Erk, which are the downstream proteins of H-ras signaling pathways. The results suggest that dehydrotrametenolic acid can be a potential anticancer agent against H-ras transformed tumor.

Blocking tumor cell migration and invasion with biphenyl isoxazole derivative KRIBB3, a synthetic molecule that inhibits Hsp27 phosphorylation

Cell migration is a prerequisite for cancer invasion and metastasis, suggesting cell motility as a potential therapeutic target for cancer treatment. A synthetic library was screened to identify inhibitors of tumor cell migration. From this, we discovered that CAC-1098 (aurintricarboxylic acid) and CBI-0997 (5-(2,4-dimethoxy-5-ethylphenyl)-4-(4-bromophenyl) isoxazole) inhibited migration of MDA-MB-231 cells with IC50 = 5 and 50 nM, respectively. We synthesized KRIBB3 (5-(5-ethyl-2-hydroxy-4-methoxyphenyl)-4-(4-methoxyphenyl) isoxazole) by replacing the bromide group of CBI-0997 with a methoxyl group. Like CBI-0997, KRIBB3 has anti-migratory and anti-invasive activities in MDA-MB-231 cells. Because KRIBB3 has a better drug-like structure, we focused our effort on further understanding its anti-migratory mechanism. Biotinyl-KRIBB3 was synthesized as an affinity probe for identification of KRIBB3-binding proteins. Using affinity chromatography, we identified Hsp27 as a target protein of KRIBB3 in vitro. Treatment of MDA-MB-231 cells with phorbol 12-myristate 13-acetate induced protein kinase C-dependent phosphorylation of Hsp27 and tumor cell migration. In contrast, treatment of MDA-MB-231 cells with KRIBB3 blocked phorbol 12-myristate 13-acetate-induced phosphorylation of Hsp27 and tumor cell migration. Furthermore, overexpression of Hsp27 antagonized the inhibitory effect of KRIBB3 on tumor cell invasion, and knockdown of Hsp27 using small interfering RNA inhibited tumor cell migration. Overall, our results demonstrate that KRIBB3 inhibits tumor cell migration and invasion by blocking protein kinase C-dependent phosphorylation of Hsp27 through its direct binding to Hsp27.

Primary clear cell sarcoma of bone

Clear cell sarcoma is a rare soft tissue sarcoma of young adults with melanocytic differentiation. It occurs predominantly in the soft tissue of extremities, typically involving tendons and aponeuroses. Primary clear cell sarcoma of bone is extremely rare. We report a case of primary clear cell sarcoma of the right first metatarsal in a 48-year-old woman and provide a literature review of the entity.

Surface modification of polyhydroxyalkanoate films and their interaction with human fibroblasts

A poly(3-hydroxybutylate-co-hydroxyvalerate) (PHA) film containing 34 mol.% 3-hydroxyvalerate (Biopol D600P) was prepared by the solvent cast method using a 10 wt.% chloroform solution of PHA. The PHA film was exposed to an oxygen plasma glow discharge to produce peroxides on its surfaces. These peroxides were then used as catalysts for the polymerization of acrylic acid (AA) in order to prepare carboxyl group-introduced PHA (PHA-C). Insulin-immobilized PHA was prepared using the coupling reaction of PU-C with insulin. The surface-modified PHAs were then characterized by attenuated total reflection Fourier transform infrared spectroscopy, electron spectroscopy for chemical analysis, and a contact angle goniometer. The amounts of insulin directly coupled to the carboxyl groups on PHA-C and coupled to the terminus amino groups of the grafted polyethylene oxide were 2.9 and 0.8 microg cm(-2), respectively. The PHA water contact angle (75 degrees ) decreased with AA grafting (33 degrees ) and insulin immobilization (31 degrees ), thereby exhibiting the increased hydrophilicity of the modified PHAs. When compared with PHA and PHA-C, the proliferation of human fibroblasts in the presence of serum was significantly accelerated on the insulin-immobilized PHAs.

Fibrosarcoma in bizarre parosteal osteochondromatous proliferation

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign lesion predominantly involving the small bones of the hands and feet. Malignant transformation in BPOP has not been documented in the English literature. This report presents the coexistence of fibrosarcoma with BPOP in the right distal fibula of an 18-year-old woman.

Grading, image analysis, and stereopsis of digitally compressed fundus images

PURPOSE

To investigate the effects of image digitization and compression on the ability to identify and quantify features in color fundus photographs.

METHODS

Color fundus photographs were digitized as tagged image file format (TIFF) and high-compression (80:1) and low-compression (30:1) joint photographic experts group (JPEG) images. Rerendered images were subjected to standard grading protocols developed for a clinical trial, and digitized images were subjected to image analysis software for drusen identification and quantitation. Re-created stereoscopic images were compared subjectively with originals.

RESULTS

Original, TIFF, and low-compression (30:1) JPEG images were virtually indistinguishable when subjected to close scrutiny with magnification. The overall quality of high-compression (80:1) JPEG images and images digitized at 500 dots per inch was markedly reduced. Protocol grading of original and digitized images was highly concordant within the repeatability of multiple grading of original images. The area subtended by drusen differed by less than 1.0% for all uncompressed and compressed image pairs quantified. Stereoscopic information was accurately preserved when compared with originals for TIFF and low-compression JPEG images.

CONCLUSIONS

Fundus images can be digitized and stored with significant compression while preserving stereopsis and image quality suitable for quantitative image analysis and semiquantitative grading. Low-compression (30:1) JPEG images may be suitable for archiving and telemedical applications.

Computerized stereochronoscopy and alternation flicker to detect optic nerve head contour change

PURPOSE/BACKGROUND

Stereochronoscopy, a technique previously explored but abandoned for glaucoma diagnosis, viewed optic nerve images acquired at separate points in time as if a stereo pair. Prior efforts to exploit this technique were impaired by a lack of superimposability for sequential optic nerve images. We investigated computerized registration techniques for aligning sequential, monoscopic optic disc images to facilitate sensitive detection of optic nerve head contour changes in glaucoma.

DESIGN

Algorithm and software development. Comparisons with standard techniques.

MATERIALS

Existing patient records from the Glaucoma Service, Scheie Eye Institute, University of Pennsylvania.

METHODS

Two sets of optic disc photographs, separated in time by 1 to 18 years, of 25 eyes with and without glaucomatous optic disc progression were digitized. We developed custom software for accurate image alignment. Change in disc morphology was then judged by digital stereochronoscopy and user-controlled alternation flicker of superimposed, time-separated images on a computer monitor. Comparisons were made with standard stereoscopic comparison.

MAIN OUTCOME MEASURE

Identification of change or no change in optic nerve head contour for images acquired at separate points in time.

RESULTS

Image processing and registration permits accurate alignment of optic disc photographs. Alternation flicker of superimposed, sequential images facilitates image comparison and detection of change as indicated by change in vessel position, color, and other cues for contour change. A high concordance was found between standard stereoscopic comparison and alternation flicker. In several cases, reinspection of stereo comparison led to a revised judgment on the basis of disc changes rendered more obvious with alternation flicker. Digital stereochronoscopy was less concordant with standard techniques.

CONCLUSIONS

Digital image processing techniques and alternation flicker provide a simple, sensitive, software-based method for detecting glaucomatous optic disc change.

Structural biology of Rad50 ATPase: ATP-driven conformational control in DNA double-strand break repair and the ABC-ATPase superfamily

To clarify the key role of Rad50 in DNA double-strand break repair (DSBR), we biochemically and structurally characterized ATP-bound and ATP-free Rad50 catalytic domain (Rad50cd) from Pyrococcus furiosus. Rad50cd displays ATPase activity plus ATP-controlled dimerization and DNA binding activities. Rad50cd crystal structures identify probable protein and DNA interfaces and reveal an ABC-ATPase fold, linking Rad50 molecular mechanisms to ABC transporters, including P glycoprotein and cystic fibrosis transmembrane conductance regulator. Binding of ATP gamma-phosphates to conserved signature motifs in two opposing Rad50cd molecules promotes dimerization that likely couples ATP hydrolysis to dimer dissociation and DNA release. These results, validated by mutations, suggest unified molecular mechanisms for ATP-driven cooperativity and allosteric control of ABC-ATPases in DSBR, membrane transport, and chromosome condensation by SMC proteins.

Subcellular phototoxicity of 5-aminolaevulinic acid (ALA)

BACKGROUND AND OBJECTIVE

5-aminolaevulinic acid (ALA) is a new, promising photosensitizer for PDT of cancer. Subcellular toxicity induced by ALA and light exposure in single cells was studied to elucidate the mechanism of cell damage.

STUDY DESIGN/MATERIALS AND METHODS

CPAE, PTK2, and rat neonatal myocardial cells treated with ALA were examined for localization using fluorescence microscopy and for subcellular phototoxicity using 630 nm laser microbeam irradiation of specific subcellular regions.

RESULTS

In CPAE and PTK2 cells, a large amount of fluorescence was detected in the peri-nuclear cytoplasm. In rat neonatal myocardial cells, the sensitizer selectively localized in the large mitochondria. In both cell types, there was little phototoxicity when the peripheral cytoplasmic region was exposed, as compared to considerable phototoxicity with exposure of either the perinuclear or nuclear regions.

CONCLUSION

Both the CPAE and PTK2 cells demonstrated that the nucleus followed by the perinuclear cytoplasm are the most sensitive cell areas with no sensitivity in the peripheral cytoplasm.

Large tumor endoprostheses and extracortical bone-bridging: 28 patients followed 10-20 years

Aseptic loosening is a common cause of failure in large tumor endoprostheses. The concept of extracortical bone-bridging was developed to tackle the problem of loosening. New bone which forms across the junction of the bone-prosthesis junction is believed to improve fixation by controlling the transfer of stresses across the junction as well as by giving additional stability to the prosthesis. We present the long-term experience with this concept following major reconstruction after tumor and non-tumor conditions in 31 patients. The overall function was good for upper and lower limb prostheses. Most patients had extracortical bone bridging which was maintained for over 10 years. In 1/3 of patients this involved over 75% of the prosthetic circumference. Prosthetic survival was best with intercalary devices, followed by proximal femoral and distal femoral prostheses. Survival of prostheses in young active patients was similar to that reported in older patients undergoing primary joint replacement.

Structure of the major peanut allergen Ara h 1 may protect IgE-binding epitopes from degradation

In the past decade, there has been an increase in allergic reactions to peanut proteins, sometimes resulting in fatal anaphylaxis. The development of improved methods for diagnosis and treatment of peanut allergies requires a better understanding of the structure of the allergens. Ara h 1, a major peanut allergen belonging to the vicilin family of seed storage proteins, is recognized by serum IgE from >90% of peanut-allergic patients. In this communication, Ara h 1 was shown to form a highly stable homotrimer. Hydrophobic interactions were determined to be the main molecular force holding monomers together. A molecular model of the Ara h 1 trimer was constructed to view the stabilizing hydrophobic residues in the three dimensional structure. Hydrophobic amino acids that contribute to trimer formation are at the distal ends of the three dimensional structure where monomer-monomer contacts occur. Coincidentally, the majority of the IgE-binding epitopes are also located in this region, suggesting that they may be protected from digestion by the monomer-monomer contacts. On incubation of Ara h 1 with digestive enzymes, various protease-resistant fragments containing IgE-binding sites were identified. The highly stable nature of the Ara h 1 trimer, the presence of digestion resistant fragments, and the strategic location of the IgE-binding epitopes indicate that the quaternary structure of a protein may play a significant role in overall allergenicity.