Relaxin prevents the development of severe acute pancreatitis

AIM： TO investigate the severity of acute pancreatitis （AP） is associated to the intensity of leukocyte activation, inflammatory up-regulation and microcirculatory disruption associated to ischernia-reperfusion injury. Hicrovascular integrity and inhibition of pro-inflammatory mediators are key-factors in the evolution of AP. Relaxin is an insulin-like hormone that has been attributed vasorelaxant properties via the nitric oxide pathway while behaving as a glucocorticoid receptor agonist. METHODS： AP was induced by the bilio-pancreatic duct-outlet-exclusion closed-duodenal-loops model. Treatment with relaxin was done at different timepoints. Nitric oxide synthase inhibition by L-NAME and glucocorticoid receptor （GR） blockage by mifepristone was considered. AP severity was assessed by biochemical and histopathological analyses. RESULTS： Treatment with relaxin reduced serum amylase, lipase, C-reactive protein, IL-6, IL-10, hsp72, LDH and 8-isoprostane as well as pancreatic and lung myeloperoxidase. Acinar and fat necrosis, hemorrhage and neutrophil infiltrate were also decreased. ATP depletion and ADP/ATP ratio were reduced while caspases 2-3-8 and 9 activities were increased. L-NAME and mifepristone decreased the efficiency of relaxin. CONCLUSION： Relaxin resulted beneficial in the treatment of AP combining the properties of a GR agonist while preserving the microcirculation and favoring apoptosis over necrosis.

Chromic-P32 phosphate treatment of implanted pancreatic carcinoma: Mechanism involved

AIM: To study the effects of chromic-P32 phosphate (32p colloids) interstitial administration in Pc-3 implanted pancreatic carcinoma, and investigate its anticancer mechanism.METHODS: Ninety-eight tumor bearing nude mice werekilled at different time points after the injection of 32Pcolloids to the tumor core with observed radioactivity. The light microscopy, transmission electron microscopy (TEM) and immuno-histochemistry and flow cytometry were used to study the rates of tumor cell necrosis, proliferating cell nuclear antigen index, the micro vessel density (MVD). The changes of the biological response to the lymphatic transported 32p colloids in the inguinal lymph node (ILN) were dynamically observed, and the percentage of tumor cell apoptosis, and Apo2.7, caspase-3, Bcl-2, Baxrelated gene expression were observed too.RESULTS: The half-life of effective medication is 13 dafter injection of 32P colloids to the tumor stroma, in 1-6groups, the tumor cell necrosis rates were 20%, 45%,65%, 70%, 95% and 4%, respectively (F= 4.14-105.36, P＜0.01). MVD were 38.5±4.0, 28.0±2.9, 17.0±2.9, 8.8±1.5,5.7±2.3 and 65.0±5.2 (t= 11.9-26.1, P＜0.01), respectively.Under TEM fairly differentiated Pc-3 cells were found. Thirty days after medication, tumors were shrunk and dried with scabs detached, and those in control group increased in size prominently with plenty of hypodermic blood vessels. In all animals the ILN were enlarged but in medicated animals they appeared later and smaller than those in control group. The extent of irradiative injury in ILN was positively correlated to the dosage of medication. Typical tumor cell apoptosis could be found under TEM inanimals with intra-tumoral injection of low dosed 32P colloids. The peak of apoptosis occurred in 2.96 MBq group and 24 h after irradiation. In the course of irradiationinduced apoptosis, the value of Bcl-2/Bax was down regulated; Apo2.7 and caspase-3 protein expression were prominently increased dose dependently. CONCLUSION: 32p colloids intra-tumor injection having prominent anticancer effectiveness may reveal the ability of promoting cell differentiation. The low dose 32P colloids may induce human pancreatic carcinoma Pc-3 implanted tumor cell apoptosis; Apo2.7, caspase-3, Bcl-2 and Bax protein participated in regulating the process of irradiation induced cell apoptosis.

Effect of itopride, a new prokinetic, in patients with mild GERD: A pilot study

AIM： Itopride is a newly developed prokinetic agent, which enhances gastric motility through both antidopaminergic and anti-acetylcholinesterasic actions. The importance of esophageal motor dysfunction in the pathogenesis of gastro-esophageal reflux disease （GERD） makes it interesting to examine the effect of itopride on esophageal acid exposure.METHODS： The effect of itopride on esophageal acid reflux variables for 24 h was studied in 26 patients with GERD symptoms, pre-entry total acid exposure time （pH〈4） of more than 5% and mild esophagitis （SavaryMiller grades I, II） proven by endoscopy. Ambulatory 24hpH-metry and symptom assessment were performed after treatments with 150 or 300 mg itopride thrice a day （t.i.d.） for 30 d in random order, using an open label method.For evaluating the safety of itopride, blood biochemical laboratory test was performed and the serum prolactin level was also examined before and after treatment.RESULTS： Total symptom score was significantly decreased after treatment in 150- or 300-mg group. Itopride 300 mg was significantly effective than 150 mg on decreasing the total per cent time with pH〈4, total time with pH〈4 and DeMeester score. No serious adverse effects were observed with administration of itopride in both groups.CONCLUSION： Itopride 100 mg t.i.d, is effective on decreasing pathologic reflux in patient with GERD and therefore it has the potential to be effective in the treatment of this disease.

Noni juice is not hepatotoxic

Noni juice （Morinda citrifolia） has been approved for use as a safe food within the European Union, following a review of safety. Since approval, three cases of acute hepatitis in Austrian noni juice consumers have been published, where a causal link is suggested between the liver dysfunction and ingestion of anthraquinones from the plant. Measurements of liver function in a human clinical safety study of TAHITIAN NONI Juice, as well as subacute and subchronic animal toxicity tests revealed no evidence of adverse liver effects at doses many times higher than those reported in the case studies. Additionally, M. citrifolia anthraquinones occur in the fruit in quantities too small to be of any toxicological significance. Further, these do not have chemical structures capable of being reduced to reactive anthrone radicals, which were implicated in previous cases of herbal hepototoxicity. The available data reveals no evidence of liver toxicity.

Demand analysis of an intelligent medication administration system for older adults with chronic diseases based on the Kano model

Objectives Gerontechnology has great potential in promoting older adults’well-being.With the accelerated aging process,gerontechnology has a promising market prospect.However,most technological developers and healthcare professionals attached importance to products’effectiveness,and ignored older adults’demands and user experience,which reduced older adults'adoption intention of gerontechnology use.The inclusion of older adults in the design process of technologies is essential to maximize the effect.This study explored older adults’demands for a self-developed intelligent medication administration system and proposed optimization schemes,thus providing reference to developing geriatric-friendly technologies and products.Methods A cross-sectional survey was conducted to explore older adults’technological demands for the self-developed intelligent medication administration system,and data were analyzed based on the Kano model.A self-made questionnaire was administered from July 2020 to October 2020 after participants used this system for two weeks.The study was registered with the Chinese Clinical Trial Registry(ChiCTR2000040644).Results A total of 354 older adults participated in the survey.Four items,namely larger font size,simpler operation process,scheduled medication reminders and reliable hardware,were classified as must-be attributes;three items,namely searching drug instructions through WeChat,more sensitive system and longer battery life,as attractive attributes;one item,viewing disease-related information through WeChat,as the one-dimensional attribute;and the rest were indifferent attributes,including simple and beautiful displays,blocking advertisements automatically,providing user privacy protection protocol,viewing personal medical information only by logged-in users,recording all the medications,ordering medications through WeChat.The satisfaction values were between 0.24 and 0.69,and dissatisfaction values were between 0.06 and 0.94.Conclusion This study suggested that older adults had personalized technology demands.Including their technological demands and desire may assist in decreasing the digital divide and promoting the satisfaction of e-health and/or m-health.Based on older adults’demands,our study proposed optimization schemes of the intelligent medication administration system,which may help developers design geriatric-friendly intelligent products and nurses to perform older adults-centered and efficient medication management.

Resveratrol: A medical drug for acute pancreatitis

Accumulating evidence demonstrates that resveratrol, a natural polyphenolic compound extracted from plants, inhibit inflammation when administered. It has direct effects on suppression of platelet coagulation and cytokines production in many experimental models. Because microcirculation occlusion and cytokines over-production is involved in many diseases such as acute pancreatitis (AP), the discovery of resveratrol as platelet and cytokines inhibitors has shed light on the treatment of AP, which still has significant mortality and morbidity. It is anticipated that this natural polyphenol could serve as a therapeutic compound in managing AP through different pathways.

Effective siRNA targets screening for human telomerase reverse transcriptase

AIM: To study the inhibitory effects of siRNAs targeting different hTERT sequences and to screen the effective siRNA sequence.METHODS: Five double-stranded siRNAs targeting coding and non-coding regions of hTERT gene were designed and synthesized by T7 transcription system in vitro. siRNA4sequence was screened by full length gene targeting technique and the rest of the siRNA sequences were selected randomly. After being purified by ethanol precipitation, the siRNAs were transfected to the human hepatocellular carcinoma cell (HepG2) by Lipofectamine 2000TM. At 48-72 h after siRNAs transfection, MTT assay,RT-PCR and Western-blot were applied to evaluate the effects of siRNAs on cell growth, mRNA and protein expression level of hTERT gene, respectively.RESULTS: Compared to the control cells, the cells treated with the five double-stranded siRNAs exhibited different degrees of inhibition of cell proliferation in a dose-dependent manner. siRNA2 and siRNA4, exhibited obvious effects of inhibiting hTERT mRNA and protein expression in HepG2cells.CONCLUSION: siRNAs targeting different hTERT sequences have significantly various inhibitory effects on hTERT gene expression. The siRNA sequence screened by full length gene targeting technique has comparable inhibitory effect with the rest siRNA sequences screened by random selection, suggesting that siRNAs and antisense oligonucleic acids may have the same effective target sites. Compared with chemical synthesis method,synthesizing double-stranded siRNA by T7 transcription system in vitro is a rapid, simple, and inexpensive method suitable for screening high-effect siRNA targeting site for specific gene.

Gastroparesis: Current diagnostic challenges and management considerations

Gastroparesis refers to abnormal gastric motility characterized by delayed gastric emptying in the absence of mechanical obstruction. The most common etiologies include diabetes, post-surgical and idiopathic. The most common symptoms are nausea, vomiting and epigastric pain. Gastroparesis is estimated to affect 4% of the population and symptomatology may range from little effect on daily activity to severe disability and frequent hospitalizations. The gold standard of diagnosis is solid meal gastric scintigraphy. Treatment is multimodal and includes dietary modification, prokinetic and anti-emetic medications, and surgical interventions. New advances in drug therapy, and gastric electrical stimulation techniques have been introduced and might provide new hope to patients with refractory gastroparesis. In this comprehensive review, we discuss gastroparesis with emphasis on the latest developments; from the perspective of the practicing clinician.

EVALUATION OF EFFICACY AND SAFETY OF DIACEREIN IN KNEE OSTEOARTHRITIS IN CHINESE PATIENTS

Objective To evaluate the efficacy and safety of diacerein in patients with knee osteoarthritis (OA). Methods A total of 223 patients satisfying the American College of Rheumatology criteria for knee OA were chosen for this 17-week, randomized, double-dummy, diclofenac sodium-controlled trial, with diacerein dosage of 100 mg/d and diclofenac sodium of 75mg/d. Efficacy and safety of both drugs were evaluated. Results Totally 106 patients in the diacerein group and 107 patients in the diclofenac group were considered qualified for the evaluation. After 12 weeks of treatment, the total effective rates of patients/physicians’ overall assessment in diacerein and diclofenac groups were 65.4%/61.6% and 61.2%/61.2%, respectively (P>0.05). The primary efficacy parameter [visual analog scale (VAS) assessment of pain on 20 metres walking] and the secondary efficacy parameters [tenderness on palpation, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short-Form (SF-36) Health Survey] significantly improved compared with baseline in both groups (P<0.05). In the follow-up period, there were no obvious changes in above parameters in diacerein group. However, in diclofenac group, pain on 20 metres walking, tenderness on palpation, and WOMAC became aggravated after withdrawing the drug for 4 weeks (P<0.05). Moreover, the consumption of paracetamol was significantly lower in diacerein group than in diclofenac group during follow-up (P<0.001). The incidences of related adverse events were 35.7% in diacerein and 45.1% in diclofenac group, respectively. Mild-to-moderate gastrointestinal disorders were the most frequent adverse events. Conclusions Diacerein is as effective as diclofenac sodium in treating patients with knee OA. Furthermore, it has better extended effect and a good safety profile. It is generally well tolerated and has no severe adverse effect.

Optimizing 6-mercaptopurine and azathioprine therapy in the management of inflammatory bowel disease

The thiopurine drugs,6-mercaptopurine(6-MP) and azathioprine,are efficacious in the arsenal of inflammatory bowel disease(IBD) therapy.Previous reports indicate that 6-thioguanine nucleotide(6-TGN) levels correlate with therapeutic efficacy,whereas high 6-methylmercaptopurine(6-MMP) levels are associated with hepatotoxicity and myelotoxicity.Due to their complex metabolism,there is wide individual variation in patient response therein,both in achieving therapeutic drug levels as well as in developing adverse reactions.Several strategies to optimize 6-TGN while minimizing 6-MMP levels have been adopted to administer the thiopurine class of drugs to patients who otherwise would not tolerate these drugs due to side-effects.In this report,we will review different approaches to administer the thiopurine medications,including the administration of 6-mercaptopurine in those unsuccessfully treated with azathioprine;coadministration of thiopurine with allopurinol;co-administration of thiopurine with anti-tumor necrosis factor α;6-TGN administration;desensitization trials;and split dosing of 6-MP.

Ocular drug delivery systems:An overview

The major challenge faced by today's pharmacologist and formulation scientist is ocular drug delivery. Topical eye drop is the most convenient and patient compliant route of drug administration,especially for the treatment of anterior segment diseases. Delivery of drugs to the targeted ocular tissues is restricted by various precorneal,dynamic and static ocular barriers. Also,therapeutic drug levels are not maintained for longer duration in target tissues. In the past two decades,ocular drug delivery research acceleratedly advanced towards developing a novel,safe and patient compliant formulation and drug delivery devices/techniques,which may surpass these barriers and maintain drug levels in tissues. Anterior segment drug delivery advances are witnessed by modulation of conventional topical solutions with permeation and viscosity enhancers. Also,it includes development of conventional topical formulations such as suspensions,emulsions and ointments. Various nanoformulations have also been introduced for anterior segment ocular drug delivery. On the other hand,for posterior ocular delivery,research has been immensely focused towards development of drug releasing devices and nanoformulations for treating chronic vitreo-retinal diseases. These novel devices and/or formulations may help to surpass ocular barriers and associated side effects with conventional topicaldrops. Also,these novel devices and/or formulations are easy to formulate,no/negligibly irritating,possess high precorneal residence time,sustain the drug release,and enhance ocular bioavailability of therapeutics. An update of current research advancement in ocular drug delivery necessitates and helps drug delivery scientists to modulate their think process and develop novel and safe drug delivery strategies. Current review intends to summarize the existing conventional formulations for ocular delivery and their advancements followed by current nanotechnology based formulation developments. Also,recent developments with other ocular drug delivery strategies employing in situ gels,implants,contact lens and microneedles have been discussed.

Liu-stain quick cytodiagnosis of ultrasound-guided fine needle aspiration in diagnosis of liver tumors

AIM： To combine ultrasound-guided fine-needle aspiration （US-FNA） and Liu （Riu） stain to make a quick study on liver tumor lesions. METHODS： Two hundred and twenty-eight aspirations from 232 patients were completely studied. The operator himself made the quick cytodiagnosis of US-FNA smear stained by Liu method within thirty minutes. The US-FNA specimen was also sent to the pathological department for cytological study and cellblock histology. The result of our Uu-stain quick cytodiagnosis in each patient was confirmed by the final cytopathological diagnosis from pathological report. RESULTS： Among 228 samples, the quick cytodiagnosis revealed 146 malignancies, 81 benign lesions and one inadequate specimen. Cytopathological diagnosis from the pathological department revealed 150 malignancies, and 78 benign lesions. Four well-differentiated hepatocellular carcinomas （HCCs） were under-diagnosed by quick cytodiagnosis as benign and 3 benign lesions were over-diagnosed as well-differentiated HCCs. Compared with cytopathological diagnosis, quick cytodiagnosis correctly diagnosed 143 malignancies and 77 benign lesions. Except for the one inadequate specimen in quick cytodiagnosis, the accuracy of quick cytodiagnosis was 96.9% （220/227）, and its sensitivity, specificity and positive and negative predictive values were 97.9%, 95.1%, 97.3% and 96.3%, respectively. CONCLUSION： Liu-stain quick cytodiagnosis is a fast, convenient, safe and effective method for hepatologists in clinic practice to diagnose liver tumor. In few cases of well-differentiated HCC, Liu-stain quick cytodiagnosis has its limitation.

Medical treatment of cholestatic liver diseases:From pathobiology to pharmacological targets

Bile secretion is dependent on the coordinated functions of a number of hepatobiliary transport systems. Cholestasis may be caused by an impairment of bile secretion, an obstruction of bile flow or a combination of the two. The common consequence of all forms of cholestasis is retention of bile acids and other potentially toxic compounds in the hepatooltes leading to apoptosis or necrosis of hepatocytes and eventually to chronic cholestatic liver disease. In certain cholestatic disorders there is also leakage of bile acids into the peribiliary space causing portal inflammation and fibrosis. The following pharmacological targets for treatment of intrahepatic cholestasis can be identified： stimulation of orthograde biliary secretion and retrograde secretion of bile acids and other toxic cholephils into the systemic circulation for excretion via the kidneys to reduce their retention in the hepatocytes; stimulation of the metabolism of hydrophobic bile acids and other toxic compounds to more hydrophilic, less toxic metabolites; protection of injured cholangiocytes against toxic effects of bile; inhibition of apoptosis caused by elevated levels of cytotoxic bile acids; inhibition of fibrosis caused by leakage of bile acids into the peribiliary space. The clinical results of ursodeoxcholic acid therapy of primary biliary cirrhosis may be regarded as the first success of this strategy.

Interferon-伪 plus lamivudine vslamivudine reduces breakthroughs, but does not affect sustained response in HBeAg negative chronic hepatitis B

AIM： To investigate the efficacy of combination treatment of IFN-α and lamivudine compared to lamivudine monotherapy, after 24 mo of administration in HBeAgnegative hepatitis B patients. METHODS： Fifty consecutive patients were randomly assigned to receive IFN-α-2b （5 MU thrice per week, n = 24） plus lamivudine （100 mg daily） or lamivudine only （n = 26） for 24 mo. Patients were followed up for further 6 mo. The primary outcome was the proportion with sustained virological response （undetectable serum HBV DNA concentrations） and or sustained biochemical response （transaminase levels within normal range） at 30 mo （6 mo after the end of therapy）. Secondary end-points were timed from initial virological （biochemical） response to VBR （BBR, respectively） and the emergence of YMDD mutants across the two arms. RESULTS： Five of twenty-four （21%） patients in the combination arm vs 3/26 （12%） in the lamivudine arm had sustained response （i.e., normal serum transaminase levels and undetectable HBV DNA by PCR assay） 6 mo after treatment discontinuation. A reduction in the emergence of YMDD mutants and in the development of virological breakthroughs was observed in patients receMng combination treatment （10% vs46% , P= 0.01 and 14% vs46% , P= 0.03, respectively）. Time from initial virologic response to virologic breakthrough （VBR） was greater among initial responders receiving combination treatment compared to those receiving lamivudine （22.9 mo vs 15.9 mo, respectively; P = 0.005）.CONCLUSION： Our results demonstrate that IFN-α plus lamivudine combination therapy does not increase the sustained response, compared to lamivudine. However, combination therapy reduces the likelihood of VBR due to YMDD mutants and prolongs the time period until the breakthrough development.

Current management strategy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) still remains a considerable challenge for surgeons.Surgery,including liver transplantation,is the most important therapeutic approach for patients with this disease.HCC is frequently diagnosed at advanced stages and has a poor prognosis with a high mortality rate even when surgical resection has been considered potentially curative.This brief report summarizes the current status of the management of this malignancy and includes a short description of new pharmacological approaches in HCC treatment.

Concomitant gastric carcinoid and gastrointestinal stromal tumors:A case report

A gastric carcinoid tumor concomitant with gastrointestinal stromal tumor （GIST） is rarely encountered in clinical practice. We report a 65-year-old female who had a 0.8 cm gastric carcinoid tumor on the posterior wall of the upper gastric corpus detected during an esophagogastroduodenoscopy at a routine physical examination, and a concomitant 1.1 cm GIST on the anterior wall of the upper gastric corpus incidentally found during surgery of the gastric carcinoid tumor. Normal serum gastrin level and histological findings suggested that she had a type 111 gastric carcinoid tumor and a GIST which were categorized a very low risk of malignancy, based on their small size and lack of mitosis. Both tumors were treated successfully by surgical excision. The patient had an uneventful recovery. Neither recurrence nor metastasis was found after a 28-mo follow-up.

Experimental study on magnetic drug targeting in treating cholangiocarcinoma based on internal magnetic fields

Objective: To evaluate the effect of magnetic nanoparticle containing 5-fluorouracil (5-FU) targeting in treating chol- angiocarcinoma based on internal magnetic fields built inside the tumor. Methods: 32 nude mice of BABL/C bearing ectopic tumor were built by subcutaneouly injecting cholangiocarcinoma cell line QBC 939. Three weeks after tumor inoculation, the animal models were divided equally into four groups at random including: (a) group A, consisting of internal magnetic field built by magnetic biliary stent wires inserted into tumor tissue and receiving magnetic nanoparticles containing 5-FU administered via tail vein injection at 250 mg/kg for consecutive five days; (b) group B, receiving placebo (sodium chloride); (c) group C, receiving pure magnetic biliary stent wires without the applying of magnetic nanoparticles; (d) group D, consisting of external magnetic fields and the same treatment of magnetic nanoparticles containing 5-FU as group A. The tumor volumes were measured every 3 days, totally six times from treatment started. Tumor tissues were observed by transmission electron microscope when the nude mice were killed after the observation period. Results: The experimental group (group A) showed significantly therapeutic efficacy. Moreover, apoptosis of tumor cells could be easily detected in this group. Conclusion: Magnetic particles containing 5-FU combined with internal magnetic field can effectively treat cholangiocarcinoma, and its therapeutic efficacy is better than that of the traditional method based on external magnetic fields.

Image-guided conservative management of right colonic diverticulitis

AIM： To study the clinical outcomes of medical therapy in patients with right colonic diverticulitis. METHODS： The records of 189 patients with right colonic diverticulitis which was finally diagnosed by computed tomography, ultrasonography, or operative findings were retrospectively reviewed. RESULTS： Of the 189 patients hospitalized for right colonic diverticulitis, the stages of diverticulitis by a modified Hinchey classification were 26 patients （13.8%） in stage 0, 139 patients （73.5%） in stage I a, 23 patients （12.2%） in stage I b, and 1 patient （0.5%） in stage Ⅲ. Medical therapy was undertaken in 185 of 189 patients （97.9%）. One hundred and eighty three of 185 patients were successfully treated with bowel rest and antibiotics. Two patients in stage I b required a resection or surgical drainage because of an inadequate response to conservative treatment. Recurrent diverticulitis developed in 15 of 183 patients （8.2%） who responded to medical therapy. All 15 patients who suffered a second attack had uncomplicated diverticulitis, and were successfully treated with medical therapy.CONCLUSION： Our results indicate that right colonic diverticulitis is essentially benign and image-guided conservative treatment is primarily required.

Drug-transporter interaction testing in drug discovery and development

The human body consists of several physiological barriers that express a number of membrane transporters. For an orally absorbed drug the intestinal, hepatic, renal and blood-brain barriers are of the greatest importance. The ATP-binding cassette(ABC) transporters that mediate cellular efflux and the solute carrier transporters that mostly mediate cellular uptake are the two superfamilies responsible for membrane transport of vast majority of drugs and drug metabolites. The total number of human transporters in the two superfamilies exceeds 400, and about 40-50 transporters have been characterized for drug transport. The latest Food and Drug Administration guidance focuses on P-glycoprotein, breast cancer resistance protein, organic anion transporting polypeptide 1B1(OATP1B1), OATP1B3, organic cation transporter 2(OCT2), and organic anion transporters 1(OAT1) and OAT3. The European Medicines Agency's shortlist additionally contains the bile salt export pump, OCT1, and the multidrug and toxin extrusion transporters, multidrug and toxin ex-trusion protein 1(MATE1) and MATE2/MATE2 K. A variety of transporter assays are available to test drugtransporter interactions, transporter-mediated drugdrug interactions, and transporter-mediated toxicity. The drug binding site of ABC transporters is accessible from the cytoplasm or the inner leaflet of the plasma membrane. Therefore, vesicular transport assays utilizing inside-out vesicles are commonly used assays, where the directionality of transport results in drugs being transported into the vesicle. Monolayer assays utilizing polarized cells expressing efflux transporters are the test systems suggested by regulatory agencies. However, in some monolayers, uptake transporters must be coexpressed with efflux transporters to assure detectable transport of low passive permeability drugs. For uptake transporters mediating cellular drug uptake, utilization of stable transfectants have been suggested. In vivo animal models complete the testing battery. Some issues, such as in vivo relevance, gender difference, age and ontogeny issues can only be addressed using in vivo models. Transporter specificity is provided by using knock-out or mutant models. Alternatively, chemical knock-outs can be employed. Compensatory changes are less likely when using chemical knockouts. On the other hand, specific inhibitors for some uptake transporters are not available, limiting the options to genetic knock-outs.