Electrophysiological evidence for context reinstatement effects on object recognition memory

Reinstating the context present at encoding during the test phase generally enhances recognition memory compared with changing the context when specific item-context associations are established during encoding. However, it remains unclear whether context reinstatement improves the performance in differentiating between old and similar items in recognition memory tests and what underlying cognitive processes are involved. Using the context reinstatement paradigm together with event-related potentials (ERP), we examined the context-dependent effects of background scenes on recognition discrimination among similar objects. Participants were instructed to associate intentionally specific objects with background scenes during the encoding phase and subsequently complete an object recognition memory task, during which old and similar new objects were presented superimposed over the studied old or similar new background scenes. Electroencephalogram was recorded to measure the electrophysiological manifestations of cognitive processes associated with episodic retrieval. Behavioral results revealed enhanced performance in differentiating old from similar objects in the old context, as opposed to the similar context condition. Importantly, ERP results indicated a more pronounced recollection-related parietal object old/new effect in the old context compared to the similar context condition. This suggests that the ability to distinguish between old and similar objects in recognition memory is primarily driven by recollection rather than familiarity, particularly when the encoding context is reinstated during the test phase. Our findings are in line with the account that the impact of context reinstatement on object recognition memory is attributable to the enhanced recollection of specific item-context associations during retrieval and provides evidence for the specificity of episodic associative representations.

Unitization of internal and external features contributes to associative recognition for faces: Evidence from modulations of the FN400

Associative recognition requires discriminating between old items and conjunction lures constructed by recombining elements from two different study items. This task can be solved not only by recollection but also by familiarity if the to-be-remembered stimuli are perceived as a unitized representation. In two event-related potential (ERP) studies, we provide evidence for the integration of internal and external facial features by showing that the early frontal old-new effect (considered a correlate of familiarity) is modulated by the specific combination of facial features. Participants studied faces consisting of internal features (eyes, eyebrows, nose, and mouth) paired with external features (hair, head shape, and ears). During the testing phase, intact, recombined, and new faces were presented. Recombined faces consisted of internal and external features taken from two different studied faces. The results showed that at the frontal sites, during the time window from 300 to 500 ms, ERPs to intact faces were more positive than those to new and recombined faces; the latter two did not differ from one another. The late parietal effect was observed only after a more extended study phase in Experiment 2. We take the modulation of the early frontal old-new effect as evidence for the contribution of familiarity to associative recognition for combinations of internal and external facial features.

[Analysis on poor efficacy factors in the treatment of recurrent/refractory B-cell lymphoma with CD19 CAR-T cells]

Objective: To investigate the factors influencing the efficacy of CD19 chimeric antigen receptor T (CAR-T) cells in the treatment of patients with relapsed refractory B cell lymphoma and to provide evidence for further improvement of CAR-T efficacy. Methods: A total of 34 patients with relapsed and refractory B-cell lymphoma were recruited from the Department of Hematology of Tianjin First Central Hospital from February 2017 to January 2019. All patients received CD19 CAR-T cell therapy. These patients were evaluated for efficacy, factors with poor efficacyand adverse effects. Results: The overall response rate was 58.8% (20/34) and the complete remission rate was 41.2% (14/34) after infusion of CD19 CAR-T cells in 34 patients with relapsed refractory B cell lymphoma. According to the efficacy of CAR-T cells, patients were divided into two groups, 20 in the effective group and 14 in the poorly effective group. The median am ount of CD19 CAR-T cell infusions in these two groups were 8.6 (5.0-12.7)×10(6)/kg and 9.7 (5.8-15.0) × 10(6)/kg, respectively, and the difference was not statistically significant (P=0.654). The percentage of CD19 CAR-T cells in the effective group and the poorly treated group was 10.28% (3.92%-44.16%) and 4.05% (0.92%-28.63%), respectively.The effective group had a higher proportion of CAR-T cells than the poorly treated group, but the difference was not statistically significant (P=0.371).The presence of massive mass was an unfavorable factor affecting the efficacy of CD19 CAR-T cells and the difference was statistically significant (P=0.001). Logistic regression multivariate analysis showed that the characteristics of massive tumors were still independent prognostic factors for poor efficacy of CD19 CAR-T cells (P=0.005, OR=0.039). Of all 34 patients, there were 70.6% (24/34) who showed varying degrees of adverse reactions after the infusion of CD19 CAR-T cells, mainly cytokines release syndrome (CRS). The median time of occurrence of fever was on the third day after infusion (0-11th) day. 16 patients were with grade 1 CRS, 7 with grade 2, and 1 with grade 3. After glucocorticoids and support treatment, they all showed improvements. Conclusions: CD19 CAR-T cell therapy has achieved a certain effect in CD19(+)B cell lymphoma, but has poor efficacy on some patients. Large mass tumors may be an adverse factors to CAR-T cell treatment.

[The value of rapid on-site evaluation (ROSE) of bronchoscopy in the diagnosis of pulmonary complications after allogeneic hematopoietic stem cell transplantation]

Objective: To investigate the value of rapid on-site evaluation (ROSE) of bronchoscopy in the diagnosis of pulmonary complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: A retrospective analysis was conducted on the diagnosis and treatment process before and after ROSE examination of 12 patients with pulmonary complications after allo-HSCT who were admitted to the Department of hematology, Tianjin First Central Hospital from January 2017 to June 2019. The diagnostic accuracy of the ROSE was evaluated by comparing the initial diagnosis of ROSE with the final clinical diagnosis. At the same time, the safety of ROSE examination was evaluated and two typical cases were shared. Results: In the 12 transbronchial lung biopsies, there were 5 cases of organizing pneumonia, 3 cases of bronchiolitis obliterans with organizing pneumonia, 1 case of pulmonary fibrosis, 1 case of acute fibrinous and organizing pneumonia, 1 case of pseudomembranous tracheobronchial aspergillosis and 1 case of uncertain diagnosis evaluated by ROSE. Compared with the final clinical diagnosis, there were 10 cases of accurate diagnosis made by ROSE (10/12). All patients were well tolerant to the operation of bronchoscopy. There was only a small amount of bleeding observed during the operation, without pneumothorax and hemoptysis. And no complications related to ROSE occurred. According to the initial diagnosis of ROSE, 10 cases of non-infectious pulmonary complications were treated with methylprednisolone or other immunosuppressive agents and 1 case of Aspergillus infection was given antifungal therapy. Seven patients with non-infectious pulmonary complications improved after treatment. One patient obtained uncertain diagnosis by ROSE was later diagnosed with virus infection by next generation sequencing technology and improved after treatment with foscarnet sodium and immunoglobulin. As of June 30, 2019, 7 patients improved and 5 died. Conclusion: ROSE has the advantages of diagnostic accuracy and rapidity, and is very suitable for patients with critical illness after hematopoietic stem cell transplantation, who are in urgent need of definite diagnosis and prompt treatment, which is beneficial to improve the prognosis of patients.

[Mucormycosis in patients with hematological diseases: seven cases reports and literature review]

目的

探讨血液病合并毛霉菌病患者的临床特征、诊治与转归，提高对该病的认识。

方法

回顾性分析2012年9月至2018年9月7例血液病合并毛霉菌病患者的临床资料，分析其临床特征、治疗过程和转归。

结果

7例血液病合并毛霉菌病患者中，男4例，女3例，中位年龄36（19~79）岁。基础疾病：急性髓系白血病2例，急性B淋巴细胞白血病、外周T细胞淋巴瘤、慢性髓性白血病急髓变、骨髓增殖性肿瘤及重型再生障碍性贫血（移植后）各1例。毛霉菌病临床类型：4例为肺型，1例为鼻眶脑型，1例为皮肤型，1例为播散型。7例患者均通过活检组织病理确诊。治疗药物为两性霉素B、两性霉素B脂质体及泊沙康唑。手术治疗4例，其中3例术中彻底清除病变组织，1例仅行局限性清除。治愈2例，好转1例，死亡4例。

结论

血液病合并毛霉菌病患者临床表现及影像学表现多样，死亡率高，确诊主要依赖于组织病理学。早期诊断、控制基础疾病、改善免疫抑制状态、尽早行有效的抗真菌药物治疗及彻底的手术清创治疗是提高血液病合并毛霉菌病患者生存率的关键。

[Relationship between cervical lesions and the type-specific viral load of high risk HPV reflected by the Ct value of Cobas 4800 HPV system]

Objective: To explore the relationship between cervical lesions and high risk HPV (HR-HPV) viral load reflected by the cycle threshold (Ct) values of Cobas 4800 HPV (Cobas 4800) system. Methods: From August 2016 to September 2017, 7 000 women from Shenzhen, were recruited for cervical cancer screening with Cobas 4800 system and cytology co-test. Colposcope biopsies were performed on women who were positive of HPV 16, 18, and positive of HPV types other than 16,18 with cytology [≥ atypical squamous cell of undetermined signification (ASCUS)], or HPV negative but abnormal of cytology [≥ low grade squamous intraepithelial lesion (LSIL)]. The Ct values of HPV 16, 18 and all combined other types coming from Cobas 4800 system were used as an indicator of viral load to analyze the relationship between type-specific HPV load and the cervical lesions. Results: (1) Among the 7 000 screening women, 370 cases were positive for cervical cancer screening, 325 of them underwent colposcope biopsies, and coloposcopy referred rate was 87.8% (325/370). Among 325 women undergoing cervical biopsy, pathological diagnosis was 119 cases of normal cervical cervix, 151 cases of LSIL, and 55 cases of high-grade squamous intraepithelial lesion (HSIL) and above (HSIL(+); including 53 cases of HSIL, 1 case of cervical adenocarcinoma, and 1 case of cervical squamous cell carcinoma). (2) The Ct value of HPV 16 was inversely correlated with the upgrading of the lesions (r=-0.617, P=0.000), and significant different among normal cervix,LSIL and HSIL(+) (35.4±4.5 vs 31.0±6.0 vs 26.5±4.0; F=25.537, P=0.000). There was no correlation between Ct value of HPV 18 and cervical lesions (r=-0.021, P=0.902). The Ct value of other 12 HPV types was statistically difference among normal normal cervix, HSIL(+) and cervicitis (33.0±5.3 vs 29.9±7.2 vs 29.8±5.8; F=5.087, P=0.007). Among them, LSIL and HSIL(+) were significantly lower than normal cervix (P<0.05), but there was no significant difference between LSIL and HSIL(+) (P>0.05). Conclusion: The Ct value of HPV 16 detecting in Cobas 4800 system as an indicator of virus load obviously correlates with different grades of cervical lesions, therefore could be a reference of cervical lesion existence and an indicator of lesion prognosis.

[Efficacy and safety of CD19 chimeric antigen receptor T cells for the treatment of 22 patients with B-cell lymphoma]

目的

探讨CD19 CAR-T治疗B细胞淋巴瘤的疗效及安全性。

方法

评估2017年2月1日至2018年7月1日CD19 CAR-T治疗22例B细胞淋巴瘤患者的疗效及不良反应情况。

结果

22例患者输注CD19 CAR-T后，总体完全缓解（CR）率为45.5%，部分缓解（PR）率为31.8%，总有效率为77.3%。其中12例复发难治患者9例有效，2例达CR，7例PR；10例微小残留病（MRD）阳性患者，8例MRD转阴。全部患者外周血中均检测到CD19 CAR-T细胞在体内增殖，复发难治患者与MRD阳性患者T细胞增殖的达峰时间分别为治疗后第4.5（1~12）天和治疗后第12（5~19）天，外周血CAR-T细胞分别占总的T淋巴细胞的4.02%（2.23%~28.60%）和10.10%（3.55%~24.74%）。MRD转阴患者持续缓解，中位随访8（3~18）个月均未复发，且此组患者有3例联合PD-1抗体治疗，均达CR。复发难治患者中，7例CAR-T治疗后达PR患者疗效保持时间为1.5~6.0个月，PD-1表达率为25.7%~55.3%，5例CAR-T治疗无效患者PD-1均高表达；共有3例患者联合应用PD-1抗体，其中2例有效；2例CAR-T治疗后达CR患者中1例行异基因造血干细胞移植，另1例随访12个月仍持续缓解。22例患者输注CAR-T细胞后14例发生不同程度的细胞因子释放综合征（CRS），其中9例为1级CRS，4例为2级CRS，其中1例复发难治患者发生3级CRS，经糖皮质激素、IL-6抗体治疗后CRS得到控制。治疗有效的17例患者中14例发生CRS，治疗无效的5例患者均未发生CRS。难治复发患者发生CRS的严重程度高于MRD阳性患者。

结论

CD19 CAR-T在CD19⁺ B细胞淋巴瘤中取得了疗效。CAR-T联合免疫检查点抑制剂的应用能够更好地提高疗效，CAR-T细胞治疗可作为复发难治患者的挽救治疗，清除B细胞淋巴瘤的MRD效果更好且不良反应小。

[The specific cytotoxicities of chimeric antigen receptor-engineered T cells on different lymphomas]

目的

探讨共刺激分子为4-1BB的二代CD19嵌合抗原受体T细胞（CAR-T细胞）对不同侵袭性淋巴瘤细胞的体内、体外杀伤活性以及CAR-T细胞在体内生存的时间。

方法

采用慢病毒包装并感染T细胞的方法制备CD19 CAR-T细胞，采用CCK-8、ELISA和乳酸脱氢酶细胞毒性检测法检测CD19 CAR-T细胞的增殖能力、炎症因子释放水平和对Raji（套细胞淋巴瘤细胞株）、Pfeiffer（弥漫大B细胞淋巴瘤细胞株）、EHEB（慢性淋巴细胞白血病细胞株）细胞的杀伤活性，采用流式细胞术分析CD19 CAR-T细胞治疗前后荷瘤裸鼠的肿瘤负荷和CAR-T细胞残留水平。

结果

①与二代CAR-T细胞比较，三代CAR-T细胞的体外（24、48 h）增殖能力（P值均<0.05）、对瘤细胞的杀伤活性（P值均<0.05）较强，差异有统计学意义；而炎症因子的释放水平差异无统计学意义（P值均>0.05）。②效靶比为4∶1且共培养48 h时，二代CD19 CAR-T细胞对Raji细胞[（72.36±2.98）%]、Pfeiffer细胞[（55.92±4.16）%]、EHEB细胞[（35.53±3.93）%]的杀伤活性从强到弱，差异有统计学意义（P=0.013）。③裸鼠体内试验结果显示二代CAR-T细胞在EHEB荷瘤小鼠体内存活时间长于Raji荷瘤小鼠（P=0.046）。

结论

共刺激分子为4-1BB的二代CD19 CAR-T细胞对惰性淋巴瘤细胞株的杀伤活性稍低于对侵袭性淋巴瘤细胞株，但在惰性淋巴瘤细胞株荷瘤小鼠体内存活时间更长，可能更适合惰性淋巴瘤的治疗。

Protective effects of deferasirox and N-acetyl-L-cysteine on iron overload-injured bone marrow

Using an iron overload mouse model, we explored the protective effect of deferasirox (DFX) and N-acetyl-L-cysteine (NAC) on injured bone marrow hematopoietic stem/progenitor cells (HSPC) induced by iron overload. Mice were intraperitoneally injected with 25 mg iron dextran every 3 days for 4 weeks to establish an iron overload (Fe) model. DFX or NAC were co-administered with iron dextran in two groups of mice (Fe+DFX and Fe+NAC), and the function of HSPCs was then examined. Iron overload markedly decreased the number of murine HSPCs in bone marrow. Subsequent colony-forming cell assays showed that iron overload also decreased the colony forming capacity of HSPCs, the effect of which could be reversed by DFX and NAC. The bone marrow hematopoiesis damage caused by iron overload could be alleviated by DFX and NAC.

[Establishment of macrophage model of iron overload in vitro and the injury induced by oxidative stress on macrophage with iron overload]

OBJECTIVE

To establish macrophage iron overload model in vitro by co-culture macrophages with iron, and to explore the effect of iron overload on cell reactive oxygen species (ROS) and the impact of ROS on macrophages.

METHOD

Iron overload group were treated with different concentrations (0, 5, 10, 20, 40, 80 μmol/L respectively) of ferric ammonium citrate (FAC). The control group was the group of macrophages without FAC treatment. We detected the number and state of cells, metabolic activity, the change of phagocytosis, the levels of ROS and reactive nitrogen, and changes of related oxidative stress signaling pathways in different groups. Changes in the above indexes were detected after application of deferasirox (DFX) to remove iron and the antioxidant N -acetylcysteine (NAC) to clear excess oxidative stress.

RESULTS

(1)The levels of labile iron pool (LIP) in macrophages co-cultivated with iron was increased with the increase of iron concentration in a dose-dependent manner. The LIP levels was the highest in the macrophages treated with 80 μmol/L. (2)The increase of FAC concentration, the metabolic activity of macrophages in the 5 FAC-treated groups decreased to 51.58%, 40.98%, 16.23%, 3.46%, and 0.05% of the activity level of the control group (all P< 0.05). The group with the metabolic activity decreased to 16.23% (20 μmol/L) was selected as the iron overload group for the following experiments. (3)Compared with the control group, the number of macrophages in the iron overload group reduced to 32.80% (P<0.05), and the state of cells changed from adherence to partial suspension. The phagocytosis of macrophages in the iron overload group reduced to 20.40% of the control group (P<0.05). (4)Our further experiment showed that the levels of ROS and the activity nitrogen in the iron overload group increased by 7.71-and 1.45-fold compared with the control group (both P<0.05). The RT-PCR showed up-regulated mRNA expression of genes related with ROS production, i. e. nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX 4) gene related with ROS production and inducible nitric oxide synthase (iNOS) gene related with reactive nitrogen production, down-regulated mRNA expression of glutathione peroxidase 1 (GPX1) gene which participated in ROS clearance. Moreover, mRNA expression of phosphatidylinositol-3-kinase (PI3K) gene involved in oxidative stress signaling pathway in the iron overload group was up-regulated, while fork head protein O3 (FOXO3) which regulated oxidative stress through negative feedback showed a down-regulation level of mRNA expression compared with the control group. (5)After iron chelation and antioxidant treatment, the above-mentioned damage in the iron overload group were partially reversed.

CONCLUSIONS

The damages of iron overload on macrophages may be mediated by inducing oxidative stress and activating oxidative stress signaling pathways. Our established model provides a method to explore the mechanism of iron overload on macrophage, and may shed some new light on possible therapeutic target in treating iron overload patients.

How Early is Infants' Attention to Objects and Actions Shaped by Culture? New Evidence from 24-Month-Olds Raised in the US and China

Researchers have proposed that the culture in which we are raised shapes the way that we attend to the objects and events that surround us. What remains unclear, however, is how early any such culturally-inflected differences emerge in development. Here, we address this issue directly, asking how 24-month-old infants from the US and China deploy their attention to objects and actions in dynamic scenes. By analyzing infants' eye movements while they observed dynamic scenes, the current experiment revealed striking convergences, overall, in infants' patterns of visual attention in the two communities, but also pinpointed a brief period during which their attention reliably diverged. This divergence, though modest, suggested that infants from the US devoted relatively more attention to the objects and those from China devoted relatively more attention to the actions in which they were engaged. This provides the earliest evidence for strong overlap in infants' attention to objects and events in dynamic scenes, but also raises the possibility that by 24 months, infants' attention may also be shaped subtly by the culturally-inflected attentional proclivities characteristic of adults in their cultural communities.

Role of p38MAPK signal transduction pathway in adhesion of hepatocellular cancinoma cell line HepG2 induced by vascular endothelial growth factor

AIM: To investigate the role of the p38MAPK signal transduction pathway in the metastasis and adhesion of hepatocellular carcinoma cell line HepG₂ induced by vascular endothelial growth factor (VEGF).

METHODS: Hepatocellular cancinoma cell line HepG₂ were or not pretreated with specific blocker (SB203580) of p38MAPK signal transduction pathway. ³H-TdR infiltration and the experiment of rat tail colloid were used to measure the effects of different concentrations of VEGF on the homotypic and hetertypic adhesion in HepG₂ cells. Flow cytometry was adopted to detect VEGF-induced expression of CD44v6 and by Boyden-Chamber assay was used to evaluate VEGF-induced metastasis of HepG₂ cells.

RESULTS: After 1 and 5 mg/L VEGF induction for 60 min, the values (dpm/min) of ³H-TdR infiltration in HepG₂ cells were 1 758.67 ± 289.46 and 1 380.03 ± 328.55; for 90 min, the values were 3 124.30 ± 2 262.14 and 2 245.60 ± 273.24, respectively. After 10 mg/L VEGF induction, the values were 1 232.32 ± 201.04, 2 337.50 ± 333.04, and 2 236.99 ± 237.07, respectively, which were dramatically lower than those in control group (P < 0.05 or 0.01). However, in the HepG₂ cells pretreated with SB203580, the values of ³H-TdR infiltration after 60, 90 and 120 min were 1 232.32 ± 201.04, 2 337.50 ± 333.04, and 2 236.99 ± 237.07, respectively, and the homotypic adhesion induced by VEGF were inhibited. After 5 and 10 mg/L induction for 60 min, the optical densities (A values) of the experiment of rat tail colloid were 0.263 ± 0.021 and 0.238 ± 0.034, respectively. After 1, 5, and 10 mg/L VEGF induction for 90 min, the A values were 0.269 ± 0.023, 0.373 ± 0.083, and 0.393 ± 0.081, respectively; for 120 min, the A values were 0.371 ± 0.061, 0.390 ± 0.074, and 0.433 ± 0.122, respectively, in HepG₂ cells, which were remarkably higher than those in control group (P < 0.05 or P < 0.01). However, in the HepG₂ cells pretreated with SB203580, the A values after 60, 90, and 120 min were 0.201 ± 0.035, 0.347 ± 0.112, and 0.479 ± 0.217, respectively, and the hetertypic adhesion induced by VEGF was restrained. After 5 mg/L VEGF induction for 2 h, the CD44v6 positive HepG₂ cells counted for a percentage of 32.6% ± 4.2%, but rate of positive cell decreased to 4.3% ± 0.54% when p38MAPK signal transduction pathway was blocked (P < 0.01).

CONCLUSION: VEGF can promote the hetertypic adhesion and decrease the homotypic adhesion of hepatocellular carcinoma HepG₂ cells by through p38MAPK signal transduction pathway, which play an important role in the invasion and metastasis of HepG₂ cells.

[Study on schistosomiasis control strategy in Ertan reservoir]

OBJECTIVE

To explore means and strategies of preventing the spread of schistosomasis transmission due to the building of Ertan Dam.

METHODS

To eliminate the infection sources and Oncomelania snails. To install concrete irrigation and piping system of water supply. To encourage the immigrants to build methane-generating tanks and improve sanitary facilities and conditions for families who live near the water-retaining line.

RESULTS

2,360 people and 152 cattle were treated for schistosome infection. Mollusciciding and environmental modification were made for eliminating snails at an area of 3,634,580 m2 and 67,105.5 m2 respectively. The length of concrete irrigation and piping system installed was 51.13 and 104.895 km respectively. Methane-generating tanks, water-heating instruments using solar energy and other sanitary facilities were established in 1,781 households. After three-year intervention, no infected snails were found and no infected human being, cattle and wild rats were detected.

CONCLUSION

Schistosomiasis control was financially supported since the very beginning of the Ertan Dam project, which provided a condition for sustainable development. Continued surveillance of snails and infection sources should be carried out, which will provide scientific basis for schistosomiasis control in the Three Gorges region as well as other new projects of hydropower and water conservancy in endemic area.

[Correlation of protein kinase C activity and its subcellular distrubution with multidrug resistance in KVB200 cells]

OBJECTIVE

To investigate the relationship between protein kinase C (PKC) and multidrug resistance (MDR) in cancer cell line KBV200.

METHODS

MTT assay was used to evaluate the IC50 of vincristine (VCR) and adriamycin (ADR) in KB cell line and its VCR-resistant derivative KBV200 cells. PKC activities in the 2 cell lines were assayed by measuring the incorporation of (32)P from [gamma-(32)P] ATP into the peptide substrates.

RESULTS

The IC50 values of VCR and ADR in KBV200 cells was 64.03 and 18.8 folds greater than those in KB cells. PKC activities of the membrane and cytosol fraction in KBV200 cells were increased compared with that in KB cells, with the total PKC activity 1.12-fold higher. Phorbol-12-myristate-13 -acetate increased PKC activity of the membrane fraction and IC50 values of KBV200 cells, while staurosporine worked to the opposite effects.

CONCLUSION

PKC may contribute to MDR mechanism in KBV200 cells.

Evaluation of in-vivo transdermal absorption of cyclosporin with absorption enhancer using intradermal microdialysis in rats

The purpose of this study was to evaluate the effect of absorption enhancer on in-vivo transdermal absorption of cyclosporin using intradermal microdialysis in rats. Cyclosporin oily solutions (0.5, 2, 8% w/v) were prepared from Sandimmun (10% w/v oily oral preparation of cyclosporin) by diluting with olive oil. 1-[2-(Decylthio)ethyl] azacyclopentan-2-one (HPE-101) and glycerin were added to the cyclosporin formulation as an absorption enhancer at various concentrations between 1 and 20%. These formulations were applied to the shaved abdomen of rats treated with intradermal microdialysis at a flow rate of 2.5 microL min-1 for 6 h. Cyclosporin was immediately detected and attained a plateau in the dermal dialysate after topical application of cyclosporin oily solution alone. Cyclosporin levels in the dialysate increased with increasing cyclosporin concentrations in the formulation from 0.5 to 8% (w/v). HPE-101 did not influence cyclosporin absorption at concentrations less than 6% (w/v). Addition of 10% (w/v) HPE-101 significantly enhanced an apparent absorption rate of cyclosporin by 4.9 times. However, 20% (w/v) HPE-101 did not show the enhancing activity. On the other hand, addition of glycerin at concentrations of 6, 10, and 20% (v/v) significantly enhanced an apparent absorption rate of cyclosporin by 3.0, 6.4, and 6.9 times, respectively. The time lag for cyclosporin absorption was less than 0.21 h in all tested cases. This microdialysis study shows that glycerin is a suitable enhancer for improving the in-vivo cyclosporin absorption from the skin.

In vivo microdialysis to determine the relative pharmacokinetics of drugs

The purpose of this study was to evaluate a simultaneous microdialysis method in blood and brain striatum to determine the relative pharmacokinetics and metabolism of L-3,4-dihydroxypenylalanine (L-dopa). L-Dopa (250 mumol/kg) was administered to rats with or without the aromatic amino acid decarboxylase (AADC) inhibitor carbidopa (25 mumol/kg) or benserazide (25 or 62.5 mumol/kg). L-Dopa, its metabolites, and AADC inhibitors in dialysates were analyzed by high performance liquid chromatography with an electrochemical detector. A moment analysis was also made to obtain pharmacokinetic parameters. After administration of L-dopa alone, it and its related metabolites were detected in both dialysates of blood and brain striatum. Coadministration of carbidopa (25 mumol/kg) or benserazide (62.5 mumol/kg) significantly enhanced the striatal amount of L-dopa by 8.0 and 6.1 times, respectively. Carbidopa and benserazide also increased striatal amounts of L-dopa metabolites, such as 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylethyleneglycol. Inhibition effect of benserazide on an extracerebral decarboxylation of L-dopa to dopamine (DA) was stronger than that of carbidopa. Carbidopa showed a higher striatal level of DA than benserazide. These results suggest a different effect of the two inhibitors on the DA formations in blood and brain striatum, and on the L-dopa transport through the blood-brain barrier (BBB). Thus, microdialysis is an easy and available method for simultaneously assessing the in vivo relative pharmacokinetics and metabolism of drugs in systemic circulation and a target organ.