A new high-density (25 electrodes/mm²) penetrating microelectrode array for recording and stimulating sub-millimeter neuroanatomical structures

OBJECTIVE

Among the currently available neural interface devices, there has been a need for a penetrating electrode array with a high electrode-count and high electrode-density (the number of electrodes/mm(2)) that can be used for electrophysiological studies of sub-millimeter neuroanatomical structures. We have developed such a penetrating microelectrode array with both a high electrode-density (25 electrodes/mm(2)) and high electrode-count (up to 96 electrodes) for small nervous system structures, based on the existing Utah Slanted Electrode Array (USEA). Such high electrode-density arrays are expected to provide greater access to nerve fibers than the conventionally spaced USEA especially in small diameter nerves.

APPROACH

One concern for such high density microelectrode arrays is that they may cause a nerve crush-type injury upon implantation. We evaluated this possibility during acute (<10 h) in vivo experiments with electrode arrays implanted into small diameter peripheral nerves of anesthetized rats (sciatic nerve) and cats (pudendal nerve).

MAIN RESULTS

Successful intrafascicular implantation and viable nerve function was demonstrated via microstimulation, single-unit recordings and histological analysis. Measurements of the electrode impedances and quantified electrode dimensions demonstrated fabrication quality. The results of these experiments show that such high density neural interfaces can be implanted acutely into neural tissue without causing a complete nerve crush injury, while mediating intrafascicular access to fibers in small diameter peripheral nerves.

SIGNIFICANCE

This new penetrating microelectrode array has characteristics un-matched by other neural interface devices currently available for peripheral nervous system neurophysiological research.

Platelet function testing to predict hyporesponsiveness to clopidogrel in patients with chest pain seen in the emergency department

Background

A dual antiplatelet regimen has been shown to reduce the risk of major adverse cardiovascular events after percutaneous coronary intervention. However, there is little information available on inhibition of platelet aggregation in patients with a prior coronary stent presenting with chest pain. This study evaluated the prevalence of hyporesponsiveness to clopidogrel and factors associated with this in patients presenting to our emergency department with chest pain who had previously undergone coronary stent placement and were prescribed dual antiplatelet therapy.

Methods

Responsiveness to clopidogrel was evaluated in a cohort of 533 consecutive stented patients presenting to the emergency department with chest pain. P2Y12 reaction units (PRU) and percent P2Y12 inhibition with clopidogrel were measured in all patients. Of 533 patients, 221 (41.6%) had PRU ≥ 230. A multivariate logistic regression model was used to determine the relationship between hyporesponsiveness to clopidogrel (defined as PRU ≥ 230) and several potential risk factors, ie, gender, age, race, type 1 or type 2 diabetes, hypertension, smoking, chronic renal failure, and obesity.

Results

There was a greater risk of hyporesponsiveness in African Americans than in non-African American patients (adjusted odds ratio [OR] = 2.165), in patients with type 2 diabetes than in those without (adjusted OR = 2.109), and in women than in men (adjusted OR = 1.813), as well as a greater risk of hyporesponsiveness with increasing age (adjusted OR = 1.167 per decade).

Conclusion

There was a high prevalence of hyporesponsiveness to clopidogrel in patients presenting with chest pain and a prior coronary stent. Non-insulin-dependent diabetes mellitus and African American race were the strongest predictors of hyporesponsiveness to clopidogrel, followed by gender and age.

Electron neutrino and antineutrino appearance in the full MINOS data sample

We report on ν(e) and ν(e) appearance in ν(μ) and ν(μ) beams using the full MINOS data sample. The comparison of these ν(e) and ν(e) appearance data at a 735 km baseline with θ13 measurements by reactor experiments probes δ, the θ23 octant degeneracy, and the mass hierarchy. This analysis is the first use of this technique and includes the first accelerator long-baseline search for ν(μ) → ν(e). Our data disfavor 31% (5%) of the three-parameter space defined by δ, the octant of the θ23, and the mass hierarchy at the 68% (90%) C.L. We measure a value of 2sin(2)(2θ13)sin(2)(θ23) that is consistent with reactor experiments.

ADAR1 is essential for intestinal homeostasis and stem cell maintenance

Adenosine deaminase acting on RNA 1 (ADAR1) is a double-stranded RNA-editing enzyme that converts adenosine (A) to inosine (I), and essential for normal development. In this study, we reported an essential role of ADAR1 in the survival and maintenance of intestinal stem cells and intestinal homoeostasis by suppressing endoplasmic reticulum (ER) stress and interferon (IFN) signaling. ADAR1 was highly expressed in the Lgr5+ cells, and its deletion in adult mice led to a rapid apoptosis and loss of these actively cycling stem cells in the small intestine and colon. ADAR1 deletion resulted in a drastic expansion of progenitors and Paneth cells but a reduction of three other major epithelial lineages. Moreover, loss of ADAR1 induced ER stress and activation of IFN signaling, and altered expression in WNT targets, followed by intestinal inflammation. An ER stress inhibitor partially suppressed crypt apoptosis. Finally, data from cultured intestinal crypts demonstrated that loss of ADAR1 in the epithelial cells is the primary cause of these effects. These results support an essential role of ADAR1 and RNA editing in tissue homeostasis and stem cells.

Direct healthcare costs of glaucoma treatment

AIMS

To report the complete lifetime direct healthcare costs of glaucoma treatment in a database of 1136 patients attending the Glaucoma Clinic at Glasgow Royal Infirmary, Glasgow, UK.

METHOD

The database was interrogated to identify all patients who had initiated treatment at the Glaucoma Clinic at Glasgow Royal Infirmary, and who had subsequently died of natural causes. The healthcare resource use based cost assessment was based on two aspects of the direct National Health Service cost: drug costs (prescribed medications) and non-drug costs (inpatient or outpatient/and surgical or procedure costs).

RESULTS

106 patients (53 men, 53 women) were identified for whom there were lifetime treatment data. The mean lifespan of the patients was 80.5 years, and the mean number of years attending the glaucoma clinic was 7.05 years (range 1-22 years). The mean cost of glaucoma treatment over the lifetime of the patients was £3001, with an annual mean cost per patient of £475. Non-drug and drug costs made up 66% and 34% respectively, of the lifetime costs.

CONCLUSIONS

This is the only study to directly assess the lifetime treatment costs of glaucoma. Awareness of the costs of glaucoma treatment may be of increased importance in these financially challenging times.

Micellar Behaviour of Copper Surfactants Derived from Fresh (Untreated) Sesame Oil and Used (Treated at High Temperature) Sesame Oil

Copper soaps have been prepared from fresh and used sesame oils. The formation of copper soaps has been confirmed by spectral technique. Micellar characterization of copper soaps has been studied by density, viscosity and ultrasonic measurements. The apparent molar volume and apparent molar compressibility have been enumerated at constant temperature using these data. The results were used to determine the critical micelle concentration (CMC), soap-solvent interaction. The results of apparent molar volume were discussed in terms of Masson's equation and the results of viscosity data have been discussed in terms of Jones-Dole equation. The CMC values are found to increase with decrease in average molecular weight of the soap. It has been observed that there is a decrease in soap-solvent interaction with the decrease in average molecular weight of copper soap.

Synthesis, Characterization and Antifungal Activities of Copper(II) Soaps and their Complexes Derived from Azadirecta Indica (Neem) and Pongamia Pinnata (Karanj) Oil

Neem (Azadirecta indica) and Karanj (Pongamia pinnata) oils are ecofriendly, non-toxic, completely biodegradable with antiviral, antifungal, and antibacterial properties. The dark green colour Copper(II) soaps derived from Neem and Karanj oil, their greenish brown complexes with ligand 2-amino-6-methyl benzothiazole containing nitrogen and sulphur have been synthesized and characterized by elemental analysis. IR and NMR of complexes suggest that the complexation has taken place successfully. From the analytical data the stoichiometry of the complexes has been observed to be 1:1 (metal-ligand). Copper soaps and their complexes are good anti-fungal agents. The fungi toxicities of the oils, soaps and complexes of neem and karanj have been investigated. The results indicate that the strain of Candida species is susceptible towards complexes of benzothiazole.

Single nucleotide polymorphisms in caprine calpastatin gene

The calpains and calpastatin (CAST) make up a major cytosolic proteolytic system, the calpain-calpastatin system, found in mammalian tissues. The relative levels of the components of the calpain-calpastatin system determine the extent of meat tenderization during postmortem storage. Calpastatin (CAST) is a protein inhibitor of the ubiquitous calcium-dependent proteases-micro-calpain and m-calpain. Polymorphisms in the bovine, ovine and pig CAST gene have been associated with meat tenderness but little is known about how caprine CAST gene may affect goat meat quality traits. In this study we selected different parts of the CAST gene: 1) that have been previously reported to be polymorphic, intron 5 and 12 and 3'UTR; 2) first time explored (exon 3, 7 and 8 and part of intron 7 and 8) to investigate polymorphic status of caprine CAST gene. Using comparative sequencing ten novel SN Ps located in exon 3 and intron 5, 7 and 8 were identified. Previously reported SNPs in intron 5, 3'UTR and intron 12 were absent. Sequence analysis revealed a non synonymous amino acid variation in exon 3, which would result in Lys/Arg substitution in the corresponding protein sequence. Considerable variation was detected in intronic regions. Twenty-four InDel were also recognized in intronic regions (15) and 3'UTR (9). All the sequences shared high homology with published bovine and ovine sequences. Three PCR-RFLP loci have been established for further analyzing genetic polymorphism in indigenous goats.

Synthesis and Characterisation of Antifungal Agents Containing Copper(II) Soaps and Derived from Mustard and Soyabean Oil

The solid copper(II) soaps derived from Mustard oil and Soyabean oil and their complexes with ligands containing nitrogen and sulphur atoms like urea, thiourea and 2-amino-6-chloro benzothiazole have been synthesized and characterised by elemental analysis, IR, NMR, ESR spectroscopy and magnetic moment studies. From the analytical data, the stoichiometry of the complexes have been observed to be 1: 1 (metal: ligand). The magnetic moment studies suggest the dimeric nature of the complexes. IR, NMR and ESR spectral details confirm that complexation has taken place successfully. The results indicate that the complexes possess elongated octahedral geometry. Conductometric studies suggest that the soaps and complexes are non-electrolytic in nature. The fungi toxicities of these ecofriendly and biodegradable soaps and complexes have been investigated.

Prevalence and morphological characterisation of Cysticercus tenuicollis (Taenia hydatigena cysts) in sheep and goat from north India

Taenia hydatigena is an adult parasite of dogs with the metacestode (Cysticercus tenuicollis) stage residing in ruminants and pigs. Documentation and surveillance data concerning to the prevalence and risk factors associated with the disease in India is largely lacking. In this experiment, 3,199 carcasses, including 760 sheep and 2,439 goat were examined for the presence of C. tenuicollis (T. hydatigena cysts) on post-mortem inspection at different slaughter houses/shops in northern India. Morphological analysis was also conducted on five samples from each species. Out of 3199 carcasses examined, 135 were found containing cysts of T. hydatigena indicating a prevalence of 4.22 %. Most of the cysts were present in abdominal cavity, except few which were embedded in the liver. The high prevalence of 4.83 was recorded in goats as compared to 2.23 % in sheep. Principal component analysis was applied for statistical analysis. The results of morphological analysis indicated its usefulness as a valid criterion for differentiation of T. hydatigena cysts and that there might be possibility of two different strains infecting sheep and goat.

Pattern of blindness in a community based hospital of Nepal

Introduction: Because of the availability of modern health facilities and moderately easy access to health services in the last 25 years, the blindness due to cataract and trachoma is expected to decline in Nepal. So it is felt that the causes of blindness need to be revised. Objective: To regroup the disease pattern leading to permanent blindness in patients attending a suburban multidisciplinary community-based hospital of Nepal. Materials and methods: A cross-sectional, descriptive study was conducted in patients attending Dhulikhel hospital over a period of 12 months, from March 2010. Only the patients with best corrected visual acuity of < 3/60 were enrolled in the study. A detailed ocular examination was carried out. Results: A total of 76 eyes of 58 patients were analyzed. Of all, 32 were male (55.2 %). The mean age of the patients was 43.03 ± 22.98, with a range of 7 years to 84 years. Retinal diseases had the higher prevalence (23, 39.7 %) followed by amblyopia (10, 17.2 %) and corneal diseases (9, 15.51 %). Anisometropic amblyopia (3.94 %) was the commonest type of amblyopia. Retinitis pigmentosa (9.21 %) and age-related macular degeneration (7.89 %) were common retinal diseases whereas anterior staphyloma (5.26 %) and leucoma (3.94 %) were common corneal diseases. Other important and rare causes of blindness included ethambutol-induced optic neuropathy and vitelliform dystrophy. Conclusion: Periodic collection of statistics on the relative frequency of the causes of blindness is important in socioeconomically developing nations like Nepal. This helps to revise the pattern of blinding diseases so that priorities can be redefined. Nepal J Ophthalmol 2013; 5(9):50-56 DOI: http://dx.doi.org/10.3126/nepjoph.v5i1.7822

Source localization of interictal spike-locked neuromagnetic oscillations in pediatric neocortical epilepsy

OBJECTIVE

To evaluate the utility of an event-related beamforming (ERB) algorithm in source localization of interictal discharges.

METHODS

We analyzed interictal magnetoencephalography data in 35 children with intractable neocortical epilepsy. We used a spatiotemporal beamforming method to estimate the spatial distribution of source power in individual interictal spikes. We compared ERB results to source localization using the equivalent current dipole model and to the seizure onset zones on intracranial EEG.

RESULTS

Focal beamformer localization was observed in 66% of patients and multifocal in the remaining 34%. ERB localized within 2 cm of the equivalent current dipole cluster centroid in 77% of the patients. ERB localization was concordant with the seizure onset zone on intracranial EEG at the gyral level in 69% of patients. Focal ERB localization area was included in the resection margin in 22/23 patients. However, focal ERB localization was not statistically associated with better surgical outcome.

CONCLUSIONS

ERB can be used for source localization of interictal spikes and can be predictive of the ictal onset zone in a subset of patients with neocortical epilepsy.

SIGNIFICANCE

These results support the utility of beamformer source localization as a fast semi-automated method for source localization of interictal spikes and planning the surgical strategy.