Proximal protection with hybrid stent, a safer combination for carotid artery stenting against carotid endarterectomy?

AIM

Carotid revascularization is an established theurapeutic modality in preventing stroke and death among patients with severe carotid stenosis. Although carotid endarterectomy remains as the primary option, carotid stenting is accepted as an alternative for patients with high risk for carotid endarterectomy. Recently published reports have better results with proximal protection devices when compared with distal protection devices. These studies have revealed less microembolic signals and less periprocedural new ischemic lesions on diffusion weighted magnetic resonance imaging. Stent choice may be also important for these procedures as open cell stent design has advantage of better flexibility whereas closed cell systems have an advantage of better scaffolding. Hybrid stents which are composed of open cells in the proximal and distal part and closed cells in the middle may carry both advantages. The aim of this study is to demonstrate whether combination of proximal protection devices with hybrid stents can be a safe alternative for carotid stenting in terms of periprocedural and 30-day outcomes.

METHODS

Here we retrospectively evaluated 68 symptomatic carotid stenosis patients undergoing carotid stenting with hybrid stent (Cristallo Ideale®, Invatec s.r.l., Medtronic, Italy) and proximal protection device (MO.MA®, Invatec s.r.l., Medtronic, Italy).

RESULTS

Our results showed only 1 minor stroke in the periprocedural period and during the first 30-day after stenting, with no death or myocardial infarction.

CONCLUSION

Although our case number is not large, we propose that carotid stenting may be safer with utilization of proximal protection system and hybrid type carotid stents.

Dominant-negative effects of KCNQ2 mutations are associated with epileptic encephalopathy

OBJECTIVE

Mutations in KCNQ2 and KCNQ3, encoding the voltage-gated potassium channels KV 7.2 and KV 7.3, are known to cause benign familial neonatal seizures mainly by haploinsufficiency. Here, we set out to determine the disease mechanism of 7 de novo missense KCNQ2 mutations that were recently described in patients with a severe epileptic encephalopathy including pharmacoresistant seizures and pronounced intellectual disability.

METHODS

Mutations were inserted into the KCNQ2 cDNA. Potassium currents were recorded using 2-microelectrode voltage clamping, and surface expression was analyzed by a biotinylation assay in cRNA-injected Xenopus laevis oocytes.

RESULTS

We observed a clear loss of function for all mutations. Strikingly, 5 of 7 mutations exhibited a drastic dominant-negative effect on wild-type KV 7.2 or KV 7.3 subunits, either by globally reducing current amplitudes (3 pore mutations) or by a depolarizing shift of the activation curve (2 voltage sensor mutations) decreasing potassium currents at the subthreshold level at which these channels are known to critically influence neuronal firing. One mutation significantly reduced surface expression. Application of retigabine, a recently marketed KV 7 channel opener, partially reversed these effects for the majority of analyzed mutations.

INTERPRETATION

The development of severe epilepsy and cognitive decline in children carrying 5 of the 7 studied KCNQ2 mutations can be related to a dominant-negative reduction of the resulting potassium current at subthreshold membrane potentials. Other factors such as genetic modifiers have to be postulated for the remaining 2 mutations. Retigabine or similar drugs may be used as a personalized therapy for this severe disease.

An overview on natural cholinesterase inhibitors--a multi-targeted drug class--and their mass production

Cholinesterase enzyme family consisting of acetylcholinesterase (AChE) and butrylcholinesterase (BChE) is important in pathogenesis of Alzheimer's disease (AD), explained by "cholinergic hypothesis". Accordingly, deficiency of the neuromediator called "acetylcholine" excessive amount of BChE has been well-described in the brains of AD patients. Consequently, cholinesterase inhibition has become one of the most-prescribed treatment strategies for AD. In fact, cholinesterase inhibitors have been also reported for their effectiveness in some other diseases including glaucoma, myasthenia gravies, as well as Down syndrome, lately. They play a role in the action of mechanism of insecticidal drugs such as carbamate derivatives as well as nerve gases such as malathion and parathion. All these utilizations can make them a multi-targeted drug class putting a special emphasis on AD therapy in the first place. Several inhibitors of cholinesterases with synthetic and natural origins are available in drug market; however, the reasons including side effects, relatively low bioavailability, etc. limit their uses in medicine and there is still a great demand to discover new cholinesterase inhibitors. Galanthamine, an alkaloid derivative isolated from snowdrop (Galanthus nivalis L.), is the latest anticholinesterase drug used against AD. Huperzine A, isolated from Huperzia serrata (Thunb.) Trev. is the most-promising drug candidate with potent anticholinesterase effect and it is a licensed anti-AD drug in China. In this review, a short introduction will be given on known cholinesterase inhibitors and, then, galanthamine and huperzine A will be covered in regard with their cholinesterase inhibitory potentials and mass productions by organic synthesis and in vitro culture techniques.

Early outcomes of carotid artery stenting

BACKGROUND AND AIM

Ischemic cerebrovascular events are the most common reason for patients to be bedridden and the third most common reason for death. Many studies in recent years have demonstrated that carotid artery stenting (CAS) may be an alternative to carotid endarterectomy (CEA). In this study, we aimed to report early outcomes of patients who were treated with CAS in our clinic and discuss practicability, advantages and safety of CAS.

METHODS AND FINDINGS

Eighty patients who underwent CAS between December 2009 and May 2011 were eligible. The mean age was 65 years (range, 49 - 89 years). Of the study group, 73.75% were males and 26.25% were female. The percentage of asymptomatic patients was 11.7%, and the remaining patients were symptomatic. A distal embolic protection device (Angioguard®) was used in 22% of the patients whereas, in the other patients (78%), a proximal blockage system (Mo.MA®) was used. Self-expandable hybrid stents were implanted in all patients and post-dilatation was performed after implantation. None of the patients suffered from stroke, myocardial infarction or death due to CAS during their hospital stay. The mean follow-up period was 10 months (range 2 - 18 months) after discharge. None of the patients had died or had a stroke, a transient ischemic attack (TIA), or a myocardial infarction during the follow-up period. Re-stenosis was not observed in the follow-up carotid Doppler ultrasonography; flow rates were within normal limits.

CONCLUSION

No major complication was observed during the early follow-up period in patients who underwent CAS in our clinic. Only 2 (2.5%) patients showed transient numbness and weakness and these did not lead to morbidity. In the management guide of extracranial carotid and vertebral artery diseases, CAS, in the light of recent studies, is recommended as an alternative to CEA in recommendations for revascularization. One of the important issues emphasized in this guide is the experience of centers. Very low complication rates after CAS suggested that, with suitable patient selection and an experienced team, similar results may be obtained.

Anion- and proton-dependent gating of ClC-4 anion/proton transporter under uncoupling conditions

ClC-4 is a secondary active transporter that exchanges Cl(-) ions and H(+) with a 2:1 stoichiometry. In external SCN(-), ClC-4 becomes uncoupled and transports anions with high unitary transport rate. Upon voltage steps, the number of active transporters varies in a time-dependent manner, resembling voltage-dependent gating of ion channels. We here investigated modification of the voltage dependence of uncoupled ClC-4 by protons and anions to quantify association of substrates with the transporter. External acidification shifts voltage dependence of ClC-4 transport to more positive potentials and leads to reduced transport currents. Internal pH changes had less pronounced effects. Uncoupled ClC-4 transport is facilitated by elevated external [SCN(-)] but impaired by internal Cl(-) and I(-). Block by internal anions indicates the existence of an internal anion-binding site with high affinity that is not present in ClC channels. The voltage dependence of ClC-4 coupled transport is modulated by external protons and internal Cl(-) in a manner similar to what is observed under uncoupling conditions. Our data illustrate functional differences but also similarities between ClC channels and transporters.

Surgery of carotid body tumour: 14 cases in 7 years

OBJECTIVE

The goal was to review our experience in the management of carotid body tumours.

MATERIAL AND METHODS

A retrospective study was performed of patients in whom carotid body tumour was diagnosed between 1998 and 2005. Data were retrieved from hospital discharge files.

RESULTS

Fourteen patients were operated on. There were five patients in Shamblin class I, 4 in class II, and 5 in class III. Duplex examination was performed in all patients. Computerized tomography scans were performed in eight (57%) patients and magnetic resonance imaging scans in five patients (36%). Angiography was performed in all patients, preoperative embolization was attempted in 5 (36%). The blood loss for these patients was not less than for those without embolization. Three patients (21%) had postoperative cranial nerve deficits. All the deficits resolved. The internal carotid artery was injured in two patients and the external carotid artery was injured in three patients (36%). No stroke occured.

CONCLUSION

Surgical resection is the treatment of choice for carotid body tumours. Observation of these tumours is not recommended because progressive growth is associated with increased risk of neurological deficits. Early surgical management is recommended to avoid neurological deficit due to a Shamblin class III tumour. We also do not recommend embolization.

Ultrasonic decalcification of calcified valve and annulus during heart valve replacement

A heavily calcified heart valve annulus increases the likelihood of sequelae after prosthetic valve replacement. Such sequelae include cerebral embolism, paravalvular leakage, valvular dysfunction, rhythm disturbance, hemolysis, communication of the heart chambers, and rupture of the posterior wall of the left ventricle. From January 1991 through June 1994, we performed heart valve replacement on 30 patients, using an ultrasonic surgical aspirator to remove calcific deposits. We placed aortic valve prostheses in 12 patients, mitral valve prostheses in 13 patients, and both aortic and mitral prostheses in 5 patients, after ultrasonic débridement of calcified annuli. All patients were re-examined 6 months after surgery: echocardiographic study showed no paravalvular leakage or valve-related complications. In our experience, ultrasonic decalcification of the annulus is superior to traditional methods. We advocate the use of ultrasonic débridement as an adjunctive tool in calcified heart valve replacement.

The effect of the male contraceptive agent gossypol acetic acid on mouse bone marrow cells in vivo: micronuclei and mitotic index

In this work the genotoxic effect of gossypol acetic acid (gossypol) was evaluated by determining the frequency of micronuclei and mitotic index in male mouse bone marrow cells in vivo. Bone marrow cells were collected at 24th hour after the single intraperitoneal (20, 40, and 80 micrograms/g) administration of gossypol. Polychromatic erythrocytes (PCEs) in the bone marrow were then evaluated with respect to micronuclei frequency. The dose-dependent increase in the micronuclei frequency was observed. However, when compared with the control group, the increase was not found to be significant (P > 0.05). Also the mitotic index values were not found to be different from those control values (P > 0.05). The results suggest that gossypol is not a clastogenic and mutagenic agent in mouse bone marrow cells in vivo.