Lack of association of ABCB1 and PXR polymorphisms with response to treatment in epilepsy

It is proposed that overexpression of P-glycoprotein (P-gp), encoded by the ABC subfamily B member 1 (ABCB1) gene, is involved in resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation and haplotype patterns are population specific which may cause different phenotypes such as response to AEDs. Although several studies examined the link between the common polymorphisms in the ABCB1 gene with resistance to AEDs, the results have been conflicting. This controversy may be caused by the effect of some confounders such as ethnicity and polytherapy. Moreover, expression of the ABCB1 gene is under the control of pregnane X receptor (PXR). Evidence showed that PXR gene contribute to the response to treatment. The aim of this study was to assess the association of ABCB1 and PXR genetic polymorphisms with response to the carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in epilepsy. Genotypes were assessed in 685 Chinese, Indian, and Malay epilepsy patients for ABCB1 (C1236T, G2677T, C3435T) and PXR (G7635A) polymorphisms. No association between these polymorphisms and their haplotypes, and interaction between them, with response to treatment was observed in the overall group or in the Chinese, Indian, and Malay subgroups. Our data showed that these polymorphisms may not contribute to the response to CBZ or VPA monotherapy treatment in epilepsy.

Hepatobiliary tuberculosis

Tuberculosis (TB) infection is still common today and remains an important cause of morbidity and mortality. Abdominal TB is one of the most prevalent forms of extrapulmonary manifestations, and collectively refers to gastrointestinal, splenic, pancreatic, hepatobiliary and abdominal lymphadenopathy involvement. The manifestation can be nonspecific, and mimics many conditions, including malignancies. Biliary involvement is extremely rare. It can directly involve or be a result of external compressions or extension from adjacent organs. Strictures can be simple or multiple and isolated or complex. Radiologically, it is difficult to exclude cholangiocarcinoma. Hepatic involvement is more common and is categorised as the miliary or isolated local type. Both can be further sub-divided into nodular or diffuse forms. The manifestations range from abscesses and tuberculomas to hepatic calcifications. Calcifications range from small isolated specks to gross calcification with or without hepatic atrophy. The diagnosis of hepatobiliary TB (HBTB) can be difficult. Ultrasonography and computed tomography are the main radiological investigations. Endoscopic retrograde cholangiography is important in the management of biliary TB. It is often important to look for the involvement of other organs and consider the coexistence of other pathologies such as malignancies. This pictorial essay reviews some of the HBTB infections that have been encountered in our tertiary referral centre.

ABCB1 C3435T polymorphism and the risk of resistance to antiepileptic drugs in epilepsy: a systematic review and meta-analysis

OBJECTIVE

The C3435T, a major allelic variant of the ABCB1 gene, is proposed to play a crucial role in drug-resistance in epilepsy. The C/C genotype carriers reportedly are at higher risk of pharmacoresistance to AEDs, but only in some studies. The hypothesis of the C-variant associated risk and resistance to antiepileptic drugs (AEDs) has been hampered by conflicting results from inadequate power in case-control studies. To assess the role of C3435T polymorphism in drug-resistance in epilepsy, a systematic review and meta-analysis was conducted.

METHODS

Databases were obtained from the Cochrane Library, MEDLINE, EMBASE, major American and European conference abstracts, and www.google.my for genetic association studies up to February 2010. All the case-control association studies evaluating the role of ABCB1 C3435T in pharmacoresistance to AEDs were identified. The new definition of treatment outcome from International League Against Epilepsy (ILAE) was used for including studies for sub-analysis. To measure the strength of genetic association for the gene variant, the odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using models of both fixed- and random-effects for comparisons of the alleles and genotypes with co-dominant (C/C vs. T/T, C/T vs. T/T), dominant (C/C+C/T vs. T/T), and recessive (C/C vs. C/T+T/T) models in overall and in ethnicity subgroups. The 19 studies were selected for the next sub-analysis based on the new definition of drug-responsiveness and drug-resistance from ILAE. The same analysis was also performed for treatment outcome and ethnicity subgroups.

RESULTS

A total of 22 association studies including 3231 (47.8%) drug-resistant patients and 3524 (52.2%) drug-responsive patients or healthy controls (genotyped for C3435T) were pooled in this meta-analysis. The allelic association of ABCB1 C3435T with risk of drug-resistance was not significant under fixed-effects model, 1.06 (95% CI 0.98-1.14, p=0.12) and random-effects model, 1.10 (0.93-1.30, p=0.28) in overall and in the subgroup analysis by ethnicity. Similar results were also obtained for all genetic models in the stratified analyses by new definition of drug-resistance by ILAE and ethnicity subgroups. There was no publication bias.

CONCLUSION

We failed to show an association between the ABCB1 C3435T polymorphism and the risk of drug-resistance suggesting a revision in contribution of this polymorphism in the multi-drug transporters hypothesis of pharmacoresistance to AEDs in epilepsy.

Eruptive syringoma in a patient with trisomy 21

Syringomas are benign adnexal neoplasia that are classified into four main types, according to their clinical features and associations. Syringoma associated with trisomy 21 typically presents with a periorbital cutaneous involvement. We report an 18-year-old Chinese girl with trisomy 21, who presented with eruptive syringoma, an unusual generalised form involving her trunk and limbs. A histological examination was performed to confirm the diagnosis.

The effects of cognitive training on community-dwelling elderly Koreans

The objective of this study was to apply and test the effects of cognitive training on community-dwelling, elderly Koreans. The cognitive training was applied for 24 weeks to 129 elderly participants. The participants were divided into two groups to receive either cognitive training followed by observational period, or observational period followed by cognitive training. The primary outcome measures were the geriatric depression scale (Geriatric Depression Scale Short Form-Korean, GDS-SF-K) and mini-mental status examination (Mini-Mental State Examination in the Korean version, MMSE-KC) scores. There were no differences between the average GDS-SF-K and MMSE-KC scores of the two groups. However, the participants with cognitive dysfunction (defined as baseline MMSE below the 16th percentile according to age, sex and educational level) who received cognitive training initially had significantly improved MMSE-KC score on weeks 8 and 16, compared with the participants with cognitive dysfunction who were observed first. However, the participants who received cognitive training later did in fact catch up with the other group in terms of MMSE-KC score. Cognitive training by visiting nursing services was more effective in the elderly with cognitive dysfunction.

Radiological manifestations of melioidosis

Melioidosis is a serious infection that is associated with high mortality. It is due to a Gram-negative bacterium, Burkholderia pseudomallei which is an environmental saprophyte found in wet soils. Melioidosis is endemic to northern Australia and the Southeast Asia. However, there is now increasing number of reports of imported cases to regions where this infection has not been previously encountered. Almost any organ can be affected. Like many other conditions, radiological imaging is an integral part of the diagnostic workup of melioidosis. Awareness of the various radiological manifestations can help direct appropriate investigations to achieve early diagnosis and the initiation of appropriate treatment. Generally, there are no known characteristic features on imaging that can specifically differentiate melioidosis from other infections. However, the "honeycomb" appearance has been described to be characteristic for large melioidosis liver abscesses. Simultaneous involvement of various organs is also characteristics. To date, there are few data available on the radiological manifestations of melioidosis. The present pictorial essay describes melioidosis affecting the various organs.

Gastrointestinal tuberculosis

Tuberculosis (TB) infection is still common and remains an important cause of morbidity and mortality, particularly in underdeveloped and developing nations. The gastrointestinal (GI) tract is the sixth commonest extrapulmonary site to be affected after lymphatic, genitourinary, bones and joints, miliary and meningeal involvement. Manifestations can be non-specific and mimic many conditions, including malignancies. Findings from endoscopy and radiological imaging are myriad, and depend on the stage of the disease and the time at which investigations are carried out. Hence, diagnosis can be difficult. Endoscopy is now the investigation of choice as it allows for visualisation and the sampling of tissue for histology and culture. This is complemented by radiological imaging. This pictorial essay reviews some of the endoscopic and radiological findings of non-human immunodeficiency virus associated proven GI TB infections that we have encountered in a tertiary referral centre.

Methylene blue related sterile endophthalmitis

To report a case of methylene blue related endophthalmitis. Observational case report. Review of clinical record, photographs. A 60 year old man developed endophthalmitis after methylene blue was accidentally used to stain the anterior capsule during phacoemulsification of cataract. His left visual acuity deteriorated from 6/12 to 6/36 two weeks after the operation. Despite intensive treatment with topical and intravitreal antibiotics, his condition deteriorated. A vitrectomy and silicone oil injection eventually managed to control the progression of the disease and salvage the eye. However the visual outcome remained poor due to corneal decompensation and retinal ischemia. Both vitreous tap and vitreous biopsy were negative for any organism. Methylene blue is extremely toxic to ocular structures and should not be used intraocularly.

Pharmacokinetic and Pharmacodynamic Interaction of Lorazepam and Valproic Acid in Relation to UGT2B7 Genetic Polymorphism in Healthy Subjects

Pharmacokinetic and pharmacodynamic profiles of lorazepam and valproate were analyzed according to uridine 5'-diphosphate-glucuronosyltransferase (UGT)2B7 genotype in 14 healthy subjects with UGT2B15*2/*2 genotype. Systemic clearance of lorazepam (2 mg intravenously) and area under the concentration-time curve (AUC) of valproate (600 mg once daily for 4 days) were analyzed as pharmacokinetic parameters, and area under the effect-time curve (AUEC) of psychomotor coordination tests (Vienna) was used for pharmacodynamic parameter. No significant differences were found in systemic clearances of lorazepam by UGT2B7 genotype. AUCs of valproate showed an increasing tendency as the number of UGT2B7*2 alleles increased, but the difference was insignificant. Psychometric results were significant among the UGT2B7 genotype group (AUEC_tracking 261.5+/-298.9 in *1/*1, and 3,396.8+/-947 in *2/*2, P=0.047) when the two drugs were coadministered. Our study suggests that the UGT2B7 genotype probably affects lorazepam-valproate pharmacodynamic interaction, especially in subjects who have homovariant genotypes of UGT2B7 and UGT2B15, although the effects on the pharmacokinetics are less significant.

Prognostic factors for neurologic outcome after endovascular revascularization of acute symptomatic occlusion of the internal carotid artery

BACKGROUND AND PURPOSE

Management of acute symptomatic internal carotid artery (ICA) occlusion remains controversial. We evaluated outcome predictors of a good recovery in patients with acute symptomatic ICA occlusion.

MATERIALS AND METHODS

We retrospectively evaluated 33 consecutive patients (men/women, 23/10; mean age, 66 years) with: 1) acute symptomatic ICA occlusion within 6 hours of symptom onset or with mismatch of symptoms and an early infarct area, 2) National Institutes of Health Stroke Scale (NIHSS) score of 6 or more, and 3) attempted endovascular revascularization of the occluded ICA. Various single and multiple variable analyses were conducted to assess the association of 14 predictors with short-term (1-month NIHSS) and long-term (1-year modified Rankin Scale [mRS]) outcomes.

RESULTS

Successful recanalization (at or more than grade 2 distal residual occlusion) was obtained in 14 (42%) of 33 and good recovery (mRS <or=2) after 1 year in 11 (33%) of 33. Distal residual occlusion (DRO; P=.005), initial NIHSS score (P=.023), and postprocedural thrombolysis in cerebral infarction (P=.027), retrograde ICA filling (P=.036), and ophthalmic collaterals (P=.046) were significant predictors of short-term outcome. DRO (P=.018) and initial NIHSS (P=.033) were significant predictors of long-term outcome on univariable analysis. DRO was the only significant predictor for short-term (P=.026) and long-term outcome (P=.033) on multivariable logistic regression.

CONCLUSIONS

Active revascularization of acute symptomatic ICA occlusion resulted in good recovery in one third of patients after 1 year. DRO is an independent predictor of a favorable clinical outcome.

Modeling of Brain D2 Receptor Occupancy-Plasma Concentration Relationships with a Novel Antipsychotic, YKP1358, Using Serial PET Scans in Healthy Volunteers

YKP1358 is a novel serotonin (5-HT(2A)) and dopamine (D(2)) antagonist that, in preclinical studies, fits the general profile of an atypical antipsychotic. We conducted a D(2) receptor occupancy study with YKP1358 in healthy volunteers using positron emission tomography (PET) to measure the D(2) receptor occupancy of YKP1358 and to characterize its relationship to plasma drug concentrations. A single oral dose, parallel group, dose-escalation (100, 200, and 250 mg) study was performed in 10 healthy male volunteers with the PET radiotracer [(11)C]raclopride. The D(2) receptor occupancy of striatum was measured pre-dose, and at 2, 5, and 10 h after YKP1358 administration. Serial blood samples were taken for measurement of plasma YKP1358 concentrations. D(2) receptor occupancy by YKP1358 increased to 53-83% at 2 h, and then decreased afterwards, ranging from 40-64% at 5 h to 20-51% at 10 h. The YKP1358 dose-plasma concentration relationship exhibited extensive variability, but there was a good relationship between plasma concentrations and D(2) receptor occupancy that was well predicted by a sigmoid E(max) model using nonlinear mixed effects modeling. To our knowledge, this is the first study in which the relationship between plasma concentration and the biomarker of D(2) receptor occupancy was modeled using nonlinear mixed effects modeling. It is anticipated that these results will be useful in estimating for subsequent studies the initial doses of YKP1358 required to achieve a therapeutically effective range of D(2) receptor occupancy.

An experimental study on the effect of encircling band procedure on silicone oil emulsification

AIM

Silicone oil is a useful tamponading material used in complex vitroretinal surgery. However, the use of silicone oil is associated with emulsification which can lead to vision threatening complications. The authors developed an experimental model to study the effect of encircling band on silicone oil emulsification.

METHODS

Two identical artificial eye chambers were constructed with circumferential indentations placed at the sphere's equator (mimicking an encircling band indentation), and filled with varying amounts of Silicone Oil 1000 centistrokes (Adato, Bausch and Lomb, UK) and balanced salt solution. The chambers were then placed on a horizontal rotating shaker, mimicking physiological saccadic eye movements, which spun the chambers at 100 Hz for 5 days at 37 degrees C. Emulsification was then quantified by dark field microscopy, digital photography, and manual counting by a masked observer.

RESULTS

The mean (standard deviation (SD)) values of silicone emulsification bubbles were as follows: in the 90% silicone oil filled chamber with no encircling band, 139.1 (SD 313.4); in the 90% silicone oil filled chamber with encircling band, 10.9 (SD 22.2) (p<0.0001); in the 75% silicone oil filled chamber with no encircling band, 103.6 (SD 272.6); in the 75% silicone oil filled chamber with encircling band, 18.5 (SD 32), (p = 0.001).

CONCLUSIONS

The emulsification of silicone oil results from friction between the silicone oil and aqueous liquids. The results from this study suggest silicone oil emulsification is reduced by (1) more complete silicone oil fill and (2) indentation from an encircling band. The authors hypothesise that both these measures resulted in reduced emulsification by reducing silicone oil/aqueous movement and resulting shearing forces.

Effect of OATP1B1 (SLCO1B1) variant alleles on the pharmacokinetics of pitavastatin in healthy volunteers

BACKGROUND

Pitavastatin is a potent, newly developed 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor for the treatment of hyperlipidemia. We characterized the effects of organic anion transporting polypeptide 1 B 1 (OATP 1 B 1) alleles *1a, *1b, and *15 on the pharmacokinetics of pitavastatin.

METHODS

Twenty-four healthy Korean volunteers who had previously participated in a pharmacokinetic study of pitavastatin (single oral dose, 1--8 mg) were further investigated. Subjects were grouped according to OATP 1 B 1 genotype. Dose-normalized area under the plasma concentration-time curve (AUC) and peak plasma concentration (C(max)) values were analyzed, because different dosages were administered to subjects, whereas the pharmacokinetics showed linear characteristics.

RESULTS

Dose-normalized pitavastatin AUCs for *1b/*1b (group 1), *1a/*1a or *1a/*1b (group 2), and *1a/*15 or *1b/*15 (group 3) were 38.8+/-13.3, 54.4 +/-12.4, and 68.1+/-6.3 ng.h.mL(-1).mg(-1) (mean+/-SD), respectively, with significant differences between all 3 groups (P=.008) and between subjects carrying and those not carrying the *15 allele (P = .004). Dose-normalized pitavastatin C(max) values were 13.2+/- 3.3, 18.2+/-5.7, and 29.4+/- 9.6 ng.mL(-1).mg(-1) in groups 1, 2, and 3, respectively, and also showed significant differences (P=.003) in a manner similar to that shown by AUC. No significant differences were found between the genotype groups in terms of dose-normalized AUC or C(max) values of pitavastatin lactone.

CONCLUSION

OATP 1 B 1 variant haplotypes were found to have a significant effect on the pharmacokinetics of pitavastatin. These results suggest that the *15 allele is associated with decreased pitavastatin uptake from blood into hepatocytes and that OATP 1 B 1 genetic polymorphisms have no effect on the pharmacokinetics of pitavastatin lactone.

Low-power hybrid wireless network for monitoring infant incubators

We have created a pilot wireless network for the convenient monitoring of temperature and humidity of infant incubators. This system combines infrared and radio frequency (RF) communication in order to minimize the power consumption of slave devices, and we therefore call it a hybrid wireless network. The slave module installed in the infant incubator receives the calling signal from the host with an infrared receiver, and sends temperature and humidity data to the host with an RF transmitter. The power consumption of the host system is not critical, and hence it uses the maximum power of infrared transmission and continuously operating RF receiver. In our test implementation, we included four slave devices. The PC calls each slave device every second and then waits for 6 s, resulting in a total scan period of 10 s. Slave devices receive the calling signals and transmit three data values (temperature, moisture, and skin temperature); their power demand is 1 mW, and can run for about 1000 h on four AA-size nickel-hydride batteries.