The Penumbra System: a mechanical device for the treatment of acute stroke due to thromboembolism

BACKGROUND AND PURPOSE

Data from recent reports have indicated that mechanical thrombectomy may have potential as a treatment for acute ischemic stroke. The purpose of this study was to assess the safety and performance of the Penumbra System (PS): a novel mechanical device designed to reduce clot burden in acute stroke due to large-vessel occlusive disease.

MATERIALS AND METHODS

A prospective, single arm, independently monitored and core laboratory adjudicated trial enrolled subjects with an acute neurologic deficit consistent with acute stroke, presenting within 8 hours of symptom onset and an angiographically verified occlusion (Thrombolysis in Myocardial Infarction [TIMI] grade 0 or 1) of a treatable intracranial vessel. The primary end point was revascularization of the target vessel to TIMI grade 2 or 3. Secondary end points were the proportion of subjects who achieved a modified Rankin Scale (mRS) score of 2 or less or a 4-point improvement on the National Institutes of Health Stroke Scale (NIHSS) score at 30-day follow-up, as well as all-cause mortality.

RESULTS

Twenty-three subjects were enrolled, and 21 target vessels were treated in 20 subjects by the PS. At baseline, mean age was 60 years, mean mRS score was 4.6, and mean NIHSS score was 21. Postprocedure, all 21 of the treated vessels (100%) were successfully revascularized by the PS to TIMI 2 or 3. At 30-day follow-up, 9 subjects (45%) had a 4-point or more NIHSS improvement or an mRS of 2 or less. The all-cause mortality rate was 45% (9 of 20), which is lower than expected in this severe stroke cohort, where 70% of the subjects at baseline had either an NIHSS score of more than 20 or a basilar occlusion.

CONCLUSION

Thus, early clinical experience suggests that the PS allows revascularization in certain subjects experiencing acute ischemic stroke.

Analgesic, anti-inflammatory and antipyretic activities of the ethanolic extract and its fractions of Cleome rutidosperma

Oral administration of the ethanolic extract (200 and 400 mg/kg, p.o) and its fractions (200 mg/kg each) of the aerial parts of Cleome rutidosperma produced significant analgesic activity in acetic acid-induced writhing and tail immersion tests, anti-inflammatory effect against carrageenin induced inflammation and adjuvant induced polyarthritis and antipyretic activity against yeast-induced pyrexia. Fractionation of the ethanolic extract potentiated the activities.

Safety and reactogenicity of a low dose diphtheria tetanus acellular pertussis vaccine (Boostrix) in pre-school Indian children

OBJECTIVE

To evaluate the safety and reactogenicity of a reduced-antigen-content combined Diphtheria Tetanus Acellular Pertussis (dTpa) vaccine in Indian preschool children.

METHODS

GlaxoSmithKline Biologicals combination dTpa vaccine was administered as a single booster dose to 347 children aged 46 years in seven centers across India. All children were subsequently followed up for two weeks for safety and reactogenicity assessment.

RESULTS

A total of 345 subjects completed the study and two subjects were lost to follow-up. One serious adverse event (head injury) unrelated to vaccination was reported. Otherwise, all subjects were in good health throughout the study period. Three subjects (0.9%) reported transient general symptoms (such as irritability and drowsiness), which prevented normal activity. Pain at injection site, swelling and redness was reported in 31.1%, 18.2% and 8.9% subjects respectively. Five subjects (1.4%) reported severe pain preventing normal movement. This resolved within 48 hours in all cases. There were no other severe local reactions including large injection site reactions.

CONCLUSION

The reduced antigen content combined dTpa vaccine is safe and well tolerated in Indian pre-school children.

Endovascular treatment of intracranial aneurysms with parent vessel reconstruction using balloon and self expandable stents

BACKGROUND AND PURPOSE

To assess the feasibility and results of parent vessel stent reconstruction with balloon expandable and self-expandable stents in the treatment of intracranial aneurysms.

METHODS

In a total of 18 aneurysms balloon expandable (group A) and self expandable (group B) stents were used in 9 cases each. Stent implantation alone was used in 3 cases, and additional coil packing in the other 15.

RESULTS

Stents were successfully deployed in 8 out of 9 in group A and in 9 out of 9 cases in group B. Nearly complete occlusion was achieved in all but one case. At 3 or 6 months stable occlusion was found in 4 group A and 2 group B patients, progressive thrombosis in 3 cases in both groups, and recanalisation in 1 case in group B. Late follow up at 1-4 years demonstrated one progressive thrombosis one recanalisation and 1 stable occlusion in 3 group A, and 2 stable occlusions in 2 group B. patients. Complications included one aneurysm perforation in group A, one in-stent thrombosis and a distal arterial perforation in group B and one groin hematoma in both groups.

CONCLUSION

Stent reconstruction of intracranial arteries harbouring aneurysms is feasible and may result in aneurysm thrombosis without coil packing in some cases. Self expanding stents seem to provide a higher rate of success. Aggressive antiplatelet treatment increases the risk of hemorrhagic complications.

Endovascular coil occlusion of intracranial aneurysms assisted by a novel self-expandable nitinol microstent (neuroform)

SUMMARY

Endovascular treatment of wide neck intracranial aneurysms is technically difficult and leads to less favorable treatment results and long term outcome. We participated in a multicenter prospective study to evaluate the safety and performance of a new self-expandable nitinol micro stent (Neuroform) in stent assisted coil occlusion of wide neck intracranial aneurysms. Eighteen patients were enrolled in the study in a single center. The anatomy of the target aneurysm and the parent vessel, technical details of the procedure, device functionality, anatomic and clinical results were evaluated. All enrolled aneurysms were either wide necked or showed an unfavorable neck-to-fundus ratio. In 16 out of 18 patients the Neuroform device allowed stent assisted coil occlusion of the aneurysm. The occlusion rate was 95% in eight patients and 100% in eight patients. The two failures were both due to anatomic reasons. Flexibility of the stent, behavior during deployment and subsequent ability to retain coils within the aneurysmal sac were considered as good as or better than the properties of previous balloon expandable stents. No device-related adverse events were encountered. Procedure-related clinical complications occurred in seven patients but caused no severe permanent neurological deficit. The Neuroform neurovascular stenting system is a safe and effective adjunct for the stent-assisted coil occlusion of wide necked intracranial aneurysms. The major advantages of this device are its self-expanding property and very high flexibility which allows safe navigation, easy sizing, as well as accurate positioning of the stent while providing sufficient bridging of the aneurysm neck for subsequent coil placement.

Oral delivery system of insulin microspheres: effect on relative hypoglycemia of diabetic albino rats

The aim of the present work was to investigate the effectiveness of a dosage form approach for monitoring both the inactivation and the absorption process by targeting insulin delivery to the upper region of small intestine. The dosage form is based on the incorporation of insulin with protease inhibitor and absorption enhancer into polyacrylic polymer Eudragit L-100. Insulin microspheres were prepared by solvent evaporation technique. And also study the effect of these microspheres upon the relative hypoglycemia (RH) effect in white diabetic albino rats has been studied in comparison to that produced after subcutaneous injection of bovine insulin solution. The oral administration of formulation with aprotinin and bile salts gave significant (p< 0.01) hypoglycemia when compared with formulation with insulin alone and with insulin and bile salts. However, the duration, course and the intensity of effect were different for each formulation. It was interesting to observe that the co-administration of aprotinin and bile salts produce prolonged and significant reduction of blood glucose level. A reduction of 4.47-36.81% in plasma glucose levels and RH of about 11.7% relative to subcutaneous injection of soluble insulin solution can be achieved by encapsulation along with protease inhibitor and bile salts.

High-frequency, depressing inhibition facilitates synchronization in globally inhibitory networks

Motivated by the study of sharp wave-associated ripples, high-frequency (approximately 200 Hz) extracellular field oscillations observed in the CA1 region of the rat hippocampus during slow-wave sleep and periods of behavioural immobility, we consider a single inhibitory neuron synapsing onto a network of uncoupled, excitatory neurons. The inhibitory synapse is depressing and has a small synaptic delay. Each excitatory cell provides instantaneous, positive feedback to the inhibitory cell. We show that the interneuron can rapidly synchronize the action potentials of the pyramidal cells if the frequency of inhibitory input is increased in a ramp-like manner as occurs during the ripple. We show that the basin of attraction of the synchronous solution is larger when the inhibition frequency is gradually increased as opposed to remaining constant.

Intussusception in southern Indian children: lack of association with diarrheal disease and oral polio vaccine immunization

BACKGROUND

Intussusception is the most common cause of intestinal obstruction in young children and has been reported as a complication of a recently withdrawn tetravalent reassortant rotavirus vaccine.

METHODS

We studied the history, clinical presentation, management and outcome of intussusception presenting to a tertiary care hospital in southern India over a 10-year period, in order to assess potential association with diarrheal disease and immunization.

RESULTS

Data from 137 index cases and 280 control subjects indicated that the risk of diarrheal disease or oral polio vaccine administration in the month prior to presentation was similar in the index cases and controls. Mean time to presentation to hospital after developing symptoms was 1.8 days, and 77.3% of patients required surgery, with 47.4% undergoing intestinal resection. Mortality was 0.006%.

CONCLUSIONS

No association could be demonstrated between gastroenteritis or oral poliovirus vaccine immunization and intussusception in southern Indian children. These children presented later and required operative intervention more frequently than has been reported in other studies, but had a good outcome with low mortality.

Phase precession and phase-locking of hippocampal pyramidal cells

We propose that the activity patterns of CA3 hippocampal pyramidal cells in freely running rats can be described as a temporal phenomenon, where the timing of bursts is modulated by the animal's running speed. With this hypothesis, we explain why pyramidal cells fire in specific spatial locations, and how place cells phase-precess with respect to the EEG theta rhythm for rats running on linear tracks. We are also able to explain why wheel cells phase-lock with respect to the theta rhythm for rats running in a wheel. Using biophysically minimal models of neurons, we show how the same network of neurons displays these activity patterns. The different rhythms are the result of inhibition being used in different ways by the system. The inhibition is produced by anatomically and physiologically diverse types of interneurons, whose role in controlling the firing patterns of hippocampal cells we analyze. Each firing pattern is characterized by a different set of functional relationships between network elements. Our analysis suggests a way to understand these functional relationships and transitions between them.

Could a herpesvirus be the cause of Kawasaki disease?

Kawasaki disease (KD) is an acute vasculitis of early childhood, the cause of which remains unknown. Many lines of evidence suggest an infectious aetiology, which may-in association with host genetic factors-lead to the characteristic clinical presentation of this disease. Accumulating data including animal models and epidemiological and immunological studies, suggest that viruses have an important role in human vasculitic disease. Whereas many infectious agents including viruses have been postulated as possible causes of KD, no single agent has been shown definitely to be associated with this disease and the causative agent remains elusive. We hypothesise that a ubiquitous virus of the gamma herpesvirus family is the likely aetiological agent for KD in genetically susceptible individuals.

Kawasaki disease: an evidence based approach to diagnosis, treatment, and proposals for future research

This article proposes a clinical guideline for the diagnosis and treatment of Kawasaki disease in the UK based on the best available evidence to date, and highlights areas of practice where evidence is anecdotal or based on retrospective data. Future research as proposed by the London Kawasaki Disease Research Group is outlined, and clinicians are invited to prospectively enroll their suspected cases into this collaborative research project.

PYK2 as a mediator of endothelin-1/G alpha 11 signaling to GLUT4 glucose transporters

Endothelin-1 (ET-1) signaling through G alpha(q/11) stimulates translocation of intracellular GLUT4 glucose transporters to the plasma membrane of 3T3-L1 adipocytes by an unknown mechanism that requires protein tyrosine phosphorylation and ADP-ribosylation factor 6 (ARF6) but is independent of phosphatidylinositol 3 (PI3)-kinase. In contrast, insulin action on this process requires PI3-kinase but not ARF6. Here we report the identification of two proteins selectively tyrosine-phosphorylated in response to ET-1 but not insulin: the Ca(2+)-activated tyrosine kinase PYK2 and its physiological substrate, the adhesion scaffold protein paxillin. Endogenous paxillin as well as expressed Myc-tagged PYK2 or a Myc-tagged kinase-deficient PYK2 protein were acutely directed to F-actin-rich adhesion sites from the adipocyte cytoplasm in response to ET-1 but not insulin. CADTK-related non-kinase (CRNK) is a dominant negative form of PYK2 containing the C-terminal portion of the protein, which binds paxillin but lacks the PYK2 autophosphorylation site (Tyr(402)). CRNK expression in 3T3-L1 adipocytes inhibited ET-1-mediated F-actin polymerization and translocation of Myc-tagged GLUT4-enhanced green fluorescent protein (EGFP) to the plasma membrane without disrupting insulin action on these processes. These data reveal the tyrosine kinase PYK2 as a required signaling element in the regulation of GLUT4 recycling in 3T3-L1 adipocytes by ET-1, whereas insulin signaling is directed through a different pathway.

G(alpha)11 signaling through ARF6 regulates F-actin mobilization and GLUT4 glucose transporter translocation to the plasma membrane

The action of insulin to recruit the intracellular GLUT4 glucose transporter to the plasma membrane of 3T3-L1 adipocytes is mimicked by endothelin 1, which signals through trimeric G(alpha)q or G(alpha)11 proteins. Here we report that murine G(alpha)11 is most abundant in fat and that expression of the constitutively active form of G(alpha)11 [G(alpha)11(Q209L)] in 3T3-L1 adipocytes causes recruitment of GLUT4 to the plasma membrane and stimulation of 2-deoxyglucose uptake. In contrast to the action of insulin on GLUT4, the effects of endothelin 1 and G(alpha)11 were not inhibited by the phosphatidylinositol 3-kinase inhibitor wortmannin at 100 nM. Signaling by insulin, endothelin 1, or G(alpha)11(Q209L) also mobilized cortical F-actin in cultured adipocytes. Importantly, GLUT4 translocation caused by all three agents was blocked upon disassembly of F-actin by latrunculin B, suggesting that the F-actin polymerization caused by these agents may be required for their effects on GLUT4. Remarkably, expression of a dominant inhibitory form of the actin-regulatory GTPase ARF6 [ARF6(T27N)] in cultured adipocytes selectively inhibited both F-actin formation and GLUT4 translocation in response to endothelin 1 but not insulin. These data indicate that ARF6 is a required downstream element in endothelin 1 signaling through G(alpha)11 to regulate cortical actin and GLUT4 translocation in cultured adipocytes, while insulin action involves different signaling pathways.