A high seizure burden increases several prostaglandin species in the hippocampus of a Scn1a+/- mouse model of Dravet syndrome

Dravet syndrome is an intractable epilepsy with a high seizure burden that is resistant to current anti-seizure medications. There is evidence that neuroinflammation plays a role in epilepsy and seizures, however few studies have specifically examined neuroinflammation in Dravet syndrome under conditions of a higher seizure burden. Here we used an established genetic mouse model of Dravet syndrome (Scn1a+/- mice), to examine whether a higher seizure burden impacts the number and morphology of microglia in the hippocampus. Moreover, we examined whether a high seizure burden influences classical inflammatory mediators in this brain region. Scn1a+/- mice with a high seizure burden induced by thermal priming displayed a localised reduction in microglial cell density in the granule cell layer and subgranular zone of the dentate gyrus, regions important to postnatal neurogenesis. However, microglial cell number and morphology remained unchanged in other hippocampal subfields. The high seizure burden in Scn1a+/- mice did not affect hippocampal mRNA expression of classical inflammatory mediators such as interleukin 1β and tumour necrosis factor α, but increased cyclooxygenase 2 (COX-2) expression. We then quantified hippocampal levels of prostanoids that arise from COX-2 mediated metabolism of fatty acids and found that Scn1a+/- mice with a high seizure burden displayed increased hippocampal concentrations of numerous prostaglandins, notably PGF2α, PGE2, PGD2, and 6-K-PGF1A, compared to Scn1a+/- mice with a low seizure burden. In conclusion, a high seizure burden increased hippocampal concentrations of various prostaglandin mediators in a mouse model of Dravet syndrome. Future studies could interrogate the prostaglandin pathways to further better understand their role in the pathophysiology of Dravet syndrome.

Interaction between Human Papillomavirus-Encoded E6 Protein and AurB Induces Cell Immortalization and Proliferation-A Potential Target of Intervention

The human papillomavirus E6 and E7 oncoproteins interact with a different subset of host proteins, leading to dysregulation of the apoptotic, cell cycle, and signaling pathways. In this study, we identified, for the first time, that Aurora kinase B (AurB) is a bona fide interacting partner of E6. We systematically characterized the AurB-E6 complex formation and its consequences in carcinogenesis using a series of in vitro and cell-based assays. We also assessed the efficacy of Aurora kinase inhibitors in halting HPV-mediated carcinogenesis using in vitro and in vivo models. We showed that AurB activity was elevated in HPV-positive cells, and this correlated positively with the E6 protein level. E6 interacted directly with AurB in the nucleus or mitotic cells. A previously unidentified region of E6, located upstream of C-terminal E6-PBM, was important for AurB-E6 complex formation. AurB-E6 complex led to reduced AurB kinase activity. However, the AurB-E6 complex increased the hTERT protein level and its telomerase activity. On the other hand, AurB inhibition led to the inhibition of telomerase activity, cell proliferation, and tumor formation, even though this may occur in an HPV-independent manner. In summary, this study dissected the molecular mechanism of how E6 recruits AurB to induce cell immortalization and proliferation, leading to the eventual cancer development. Our findings revealed that the treatment of AZD1152 exerted a non-specific anti-tumor effect. Hence, a continuous effort to seek a specific and selective inhibitor that can halt HPV-mediated carcinogenesis should be warranted.

Herb-drug interaction of gastrodiae rhizoma on carbamazepine: A pharmacokinetic study in rats

OBJECTIVE

Gastrodiae Rhizoma (GR), is a traditional Chinese Medicine that has been used for neurological disorders, including epilepsy. Epilepsy patients may be treated with adjunctive therapy of GR with antiepileptic drugs (AEDs). In particular, carbamazepine (CBZ) is of high potential to interact with concurrent treatment of Chinese Medicine. This study was to investigate the herb-drug interactions of GR and CBZ, an AED, through pharmacokinetic approach in rats.

METHODS

We adopted a high-performance liquid chromatography (HPLC) system to quantify the plasma level of CBZ and its metabolite (carbamazepine-10, 11-epoxide, CBZE). The method was validated as per instructions under United States Food and Drug Administration (USFDA) guidance. For the herb-drug interaction study, rats were randomly divided into four different treatment groups: single-dose CBZ treatment, single-dose CBZ/GR treatment, 2-week course of CBZ treatment and 2-week course of CBZ/GR treatment.

RESULTS

Our results demonstrated the auto-induction of CBZ metabolization when comparing single-dose with 2-week course of CBZ treatment. Pharmacokinetic interactions were noted in concomitant use of GR with CBZ by comparing two single-dose treatments (CBZ versus CBZ/GR). Our data showed that GR increased the mean residence time (MRT0-t) and the time taken to reach the maximum concentration (Tmax) of CBZ in single-dose of CBZ/GR treatment. The maximum drug concentration (Cmax) of CBZ was reduced in single-dose CBZ/GR treatment. When comparing the 2-week course of CBZ treatment with the 2-week course of CBZ/GR treatment, the MRT0-t and half-life of CBZ were increased. The AUC0-t, the Cmax and the half-life of CBZE were increased.

CONCLUSION

CBZ/GR treatment may reduce the auto-induction of CBZ over 2 weeks. While the reduction of auto-induction could enhance the therapeutic effects of CBZ, it could also lead to an increase in neurological side effects and non-neurological adverse effects. Our results provided preclinical evidence of herb-drug interaction, which may have implications for epilepsy patients treated with GR.

The antiepileptic effect of Gastrodiae Rhizoma through modulating overexpression of mTOR and attenuating astrogliosis in pilocarpine mice model

Objective

To investigate the effect of water extract of Gastrodiae Rhizoma (GR) on the development of acquired temporal lobe epilepsy (TLE) and on regulating the expression of the mammalian target of rapamycin (mTOR) and semaphorin 3F (SEMA3F).

Methods

A pilocarpine‐induced status epilepticus (SE) model was adopted to precipitate injury in the limbic systems. GR and carbamazepine (CBZ) treatments were given to mice for 14 days prior to SE induction to demonstrate the antiepileptic effects and continued for 5 more days to illustrate the effects on histologic studies.

Results

Our results consolidated that GR treatment (92.1 minutes) could delay the SE onset in comparison with the control group (61.5 minutes, P = .041). Fewer mice had reached SE with GR treatment (41.7%) when compared with the control group (83.3%, P = .044). GR treatment (2.1 hours/mouse) could suppress the number of acute seizures in post‐SE survival mice when compared with the control group (4.5 hours/mouse, P < .001). The effects of GR treatment were elucidated with the mechanism of actions. GR treatment reduced the overexpression of mTOR (0.27 vs 0.67 AU/mg protein, P = .047). GR treatment increased the underexpression of SEMA3F (0.51 vs 0.16 µg/mg protein, P = .034). In the histochemical study of microtubule‐associated protein 2 (MAP2) staining, our results showed that GR prevented neuronal loss in the GR treatment group (64.8% positively stained pixel area) as compared with the control group (59%, P = .014) in the hippocampus. In glial fibrillary acidic protein (GFAP) staining, the severity of astrogliosis was mitigated by the GR treatment (4.1% positively stained pixel area) when compared to the control group (5.6%, P = .047) in the hippocampus.

Significance

These results provide preclinical evidence to support the use of GR, which could suppress acute seizures and relieve pathological changes in pilocarpine‐induced TLE mice. We demonstrated that the antiepileptic effects of GR could be accompanied by mTOR reduction and astrogliosis attenuation.

Grayanotoxin poisoning from Rhododendron simsii in an infant

We report a case of severe poisoning in a 57-day-old infant who presented with vomiting, convulsions, and shock after ingesting a bottle of milk containing a decoction of Rhododendron simsii. The grandmother collected this toxic plant from a cultivated area, believing it was good for the airways. Grayanotoxin was detected in both the urine and plant specimens. The infant made a good recovery after requiring ventilatory support for 2 days. Rhododendron is a common gardening shrub in Hong Kong. Some Rhododendron species are poisonous and contain grayanotoxin. Intentional or accidental ingestion of toxic plants can be severe or even life-threatening. It is therefore essential that clinicians be familiar with local toxic plant species.

Authentication of Panax notoginseng by 5S-rRNA spacer domain and random amplified polymorphic DNA (RAPD) analysis

The great majority of Panax species are well-known herbal medicines in the Orient, and many of them share a close resemblance in appearance and chemical composition. Among these Panax species, the root of P. notoginseng (Sanqi) is a unique herb that has distinct clinical usage. Here, the 5S-rRNA spacer domains were isolated from P. notoginseng, P. japonicus var. major, P. stipuleanatus, P. quinquefolius, P. ginseng, P. zingiberensis, and P. wangianus, and four common adulterants of P. notoginseng including Curcuma wenyujin, Curcuma longa, Bletilla striata and Gynura segetum. The spacer domains were sequenced and compared, which showed over 75 % DNA identity among all Panax species, but not for the adulterants. In addition, random amplification of polymorphic DNA (RAPD) analysis was used to distinguish different members of Panax genus as well as the morphological variants of P. notoginseng. These molecular methods could be used in the authentic identification of P. notoginseng from other Panax species.

Bruton's tyrosine kinase mutations in 8 Chinese families with X-linked agammaglobulinemia

Bruton's tyrosine kinase (BTK) is involved in B-cell development. Mutation of BTK results in X-linked agammaglobulinemia (XLA). BTK is expressed in most haemopoietic lineages except mature T cells and plasma cells. We identified six novel and two known mutations of BTK in 11 Chinese XLA patients from 8 families. Family 1 had a novel point mutation at the start codon (135G-->T) in exon 2. Family 2 had known mutation of single A insertion in a stretch of 7 A residues (341-347insA) recognized as mutation hotspot in exon 3. Family 3 had a novel point mutation in exon 11 (1074A-->G) which led to aberrant splicing. Family 4 had known mutation in exon 19 (2053C-->T) in CpG mutation hotspot. The novel mutation of family 5 was an A deleted in a run of three As (1017-1019delA) in exon 10. In family 6, exons 2 and 3 were lost in BTK mRNA, a novel deletion. Family 7 had a novel substitution in exon 2 (227T-->C) which led to change of a conserved leucine to serine. Family 8 had a novel point mutation at beginning of intron 14 (IVS14+ 6 T-->G) resulting in aberrant splicing. Hum Mutat 15:385, 2000.

Understanding the relative sensitivity of radiographic screens to scattered radiation

This study compared the relative response of various screen-film and computed radiography (CR) systems to diagnostic radiation exposure. An analytic model was developed to calculate the total energy deposition within the depth of screen and the readout signal generated from this energy for the x-ray detection system. The model was used to predict the relative sensitivity of several screen-film and CR systems to scattered radiation as a function of various parameters, such as x-ray spectra, phantom thickness, phosphor composition, screen thickness, screen configuration (single front screen, single back screen, screen pair), and readout conditions. In addition, measurements of the scatter degradation factor (SDF) for different screen systems by using the beam stop technique with water phantoms were made to verify the model results. Theoretically calculated values of SDF were in good agreement with experimental data. These results are consistent with the common observation that rare-earth screens generally produce better image quality than calcium tungstate screens and the CR screen.