Notes from the field: severe illness associated with reported use of synthetic marijuana - Colorado, August-September 2013

On August 30, 2013, the Colorado Department of Public Health and Environment (CDPHE) was notified by several hospitals of an increase in the number of patients visiting their emergency departments (EDs) with altered mental status after using synthetic marijuana. Synthetic marijuana is dried plant material sprayed with various synthetic cannabinoids and smoked as an alternative to smoking marijuana. In response to the increase in ED visits associated with the use of synthetic marijuana, CDPHE asked all Colorado EDs to report through EMResource (a web-based reporting system) any patients examined on or after August 21 with altered mental status after use of a synthetic marijuana product. Serum and urine specimens from patients also were requested. On September 8, CDPHE, with the assistance of CDC, began an epidemiologic investigation to characterize the outbreak, determine the active substance and source of the synthetic marijuana product, and prevent further morbidity and mortality. Investigators reviewed ED visit reports submitted through EMResource and medical charts. A probable case was defined as any illness resulting in a visit to a Colorado ED during August 21-September 18, 2013, by a patient with suspected synthetic marijuana use in the 24 hours preceding illness onset. Of 263 patient visits reported to CDPHE through EMResource (214) and other means, such as e-mail and fax (49), a total of 221 (84%) represented probable cases (Figure).

The genetic rescue of two bottlenecked South Island robin populations using translocations of inbred donors

Populations forced through bottlenecks typically lose genetic variation and exhibit inbreeding depression. 'Genetic rescue' techniques that introduce individuals from outbred populations can be highly effective in reversing the deleterious effects of inbreeding, but have limited application for the majority of endangered species, which survive only in a few bottlenecked populations. We tested the effectiveness of using highly inbred populations as donors to rescue two isolated and bottlenecked populations of the South Island robin (Petroica australis). Reciprocal translocations significantly increased heterozygosity and allelic diversity. Increased genetic diversity was accompanied by increased juvenile survival and recruitment, sperm quality, and immunocompetence of hybrid individuals (crosses between the two populations) compared with inbred control individuals (crosses within each population). Our results confirm that the implementation of 'genetic rescue' using bottlenecked populations as donors provides a way of preserving endangered species and restoring their viability when outbred donor populations no longer exist.

Development and function of the voltage-gated sodium current in immature mammalian cochlear inner hair cells

Inner hair cells (IHCs), the primary sensory receptors of the mammalian cochlea, fire spontaneous Ca²⁺ action potentials before the onset of hearing. Although this firing activity is mainly sustained by a depolarizing L-type (Ca_V1.3) Ca²⁺ current (I_Ca), IHCs also transiently express a large Na⁺ current (I_Na). We aimed to investigate the specific contribution of I_Na to the action potentials, the nature of the channels carrying the current and whether the biophysical properties of I_Na differ between low- and high-frequency IHCs. We show that I_Na is highly temperature-dependent and activates at around −60 mV, close to the action potential threshold. Its size was larger in apical than in basal IHCs and between 5% and 20% should be available at around the resting membrane potential (−55 mV/−60 mV). However, in vivo the availability of I_Na could potentially increase to >60% during inhibitory postsynaptic potential activity, which transiently hyperpolarize IHCs down to as far as −70 mV. When IHCs were held at −60 mV and I_Na elicited using a simulated action potential as a voltage command, we found that I_Na contributed to the subthreshold depolarization and upstroke of an action potential. We also found that I_Na is likely to be carried by the TTX-sensitive channel subunits Na_V1.1 and Na_V1.6 in both apical and basal IHCs. The results provide insight into how the biophysical properties of I_Na in mammalian cochlear IHCs could contribute to the spontaneous physiological activity during cochlear maturation in vivo.

Restoration of auditory evoked responses by human ES-cell-derived otic progenitors

Deafness is a condition with a high prevalence worldwide, produced primarily by the loss of the sensory hair cells and their associated spiral ganglion neurons (SGNs). Of all the forms of deafness, auditory neuropathy is of a particular concern. This condition, defined primarily by damage to the SGNs with relative preservation of the hair cells ¹, is responsible for a substantial proportion of patients with hearing impairment ². While the loss of hair cells can be circumvented partially by a cochlear implant, no routine treatment is available for sensory neuron loss since poor innervation limits the prospective performance of an implant ³. Using stem cells to recover the damaged sensory circuitry is a potential therapeutic strategy. Here, we present a protocol to induce differentiation from human embryonic stem cells (hESCs) using signals involved in the initial specification of the otic placode. We obtained two types of otic progenitors able to differentiate in vitro into hair cell-like cells and auditory neurons that display expected electrophysiological properties. Moreover, when transplanted into an auditory neuropathy model, otic neuroprogenitors engraft, differentiate and significantly improve auditory evoked response (ABR) thresholds. These results should stimulate further research into the development of a cell-based therapy for deafness.

Auditory function in the Tc1 mouse model of down syndrome suggests a limited region of human chromosome 21 involved in otitis media

Down syndrome is one of the most common congenital disorders leading to a wide range of health problems in humans, including frequent otitis media. The Tc1 mouse carries a significant part of human chromosome 21 (Hsa21) in addition to the full set of mouse chromosomes and shares many phenotypes observed in humans affected by Down syndrome with trisomy of chromosome 21. However, it is unknown whether Tc1 mice exhibit a hearing phenotype and might thus represent a good model for understanding the hearing loss that is common in Down syndrome. In this study we carried out a structural and functional assessment of hearing in Tc1 mice. Auditory brainstem response (ABR) measurements in Tc1 mice showed normal thresholds compared to littermate controls and ABR waveform latencies and amplitudes were equivalent to controls. The gross anatomy of the middle and inner ears was also similar between Tc1 and control mice. The physiological properties of cochlear sensory receptors (inner and outer hair cells: IHCs and OHCs) were investigated using single-cell patch clamp recordings from the acutely dissected cochleae. Adult Tc1 IHCs exhibited normal resting membrane potentials and expressed all K(+) currents characteristic of control hair cells. However, the size of the large conductance (BK) Ca(2+) activated K(+) current (I(K,f)), which enables rapid voltage responses essential for accurate sound encoding, was increased in Tc1 IHCs. All physiological properties investigated in OHCs were indistinguishable between the two genotypes. The normal functional hearing and the gross structural anatomy of the middle and inner ears in the Tc1 mouse contrast to that observed in the Ts65Dn model of Down syndrome which shows otitis media. Genes that are trisomic in Ts65Dn but disomic in Tc1 may predispose to otitis media when an additional copy is active.

[Alcohol and drug misuse of the elderly in health care facilities]

OBJECTIVE

A nationwide representative survey was conducted in residential care facilities and facilities offering care for the elderly in their homes (home care facilities) with the aim to estimate the rate of alcohol and drug misuse among this population and to evaluate the way in which nursing staff deal with the problem.

METHOD

A total of 5000 randomly selected facilities were contacted with a 2-page questionnaire. Reliable data were obtained from 550 residential care facilities and from 436 home care facilities.

RESULTS

According to the investigated facilities, the mean rate of misuse among the elderly was 14%. Nearly all facilities acknowledge the necessity to react to these facts, but only a quarter of them considered their staff to be sufficiently trained. 38.4% of the residential care facilities and 26.9% of the home care facilities have a concept on how to react to misuse problems. Addiction services are rarely contacted.

CONCLUSIONS

The prevalence of alcohol and drug misuse among the elderly in health care facilities is high compared to the same age cohort of the total population. The lack of networking between facilities for the elderly and addiction services is remarkable.

Biomechanical comparison of an interspinous device and a rigid stabilization on lumbar adjacent segment range of motion

PURPOSE OF THE STUDY

Decompression surgery with or without fusion is the gold standard treatment of lumbar spinal stenosis, but adjacent segment degeneration has been reported as a long-term complication after fusion. This led to the development of dynamic implants like the interspinous devices. They are supposed to limit extension and expand the spinal canal at the symptomatic level, but with reduced effect on the range of motion of the adjacent segments. The aim of the present study is the evaluation of the biomechanical effects on the range of motion (ROM) of adjacent lumbar segments after decompression and instrumentation with an interspinous device compared to a rigid posterior stabilization device.

MATERIALS AND METHODS

Eight fresh frozen human cadaver lumbar spines (L2-L5) were tested in a spinal testing device with a moment of 7.5 Nm in flexion/extension, lateral bending and rotation with and without a preload. The preload was applied as a follower load of 400N along the curvature of the spine. The range of motion (ROM) of the adjacent segments L2/L3 and L4/L5 was measured with the intact segment L3/L4, after decompression, consisting of resection of the interspinous ligament, flavectomy and bilateral medial facetecomy, and insertion of the Coflex® (Paradigm Spine, Wurmlingen) and after instrumentation with Click X® (Synthes, Umkirch) as well.

RESULTS

The interspinous and the rigid device caused a significant increase of ROM at both adjacent segments during all directions of motion and under follower load, without significant difference between these devices. The ROM of L2/L3 tends to increase more than the ROM of L4/L5 after instrumentation without statistical significance.

DISCUSSION

The "dynamic" Coflex device caused a significant increase of ROM at both adjacent lumbar segments comparable to the increase of ROM after instrumentation with the rigid Click X device. Other in vitro studies observed comparable biomechanical effects on the adjacent segments after fusion, but biomechanical spacer studies concentrated on the "noncompressible" X-Stop® and could not demonstrate a significant adjacent segment effect of this device.

CONCLUSIONS

The hypothesis, that an interspinous device would reduce the stress on adjacent segments compared to a rigid posterior stabilization device, could not be demonstrated with this biomechanical in vitro study. Therefore, the protection of adjacent segments after instrumentation with dynamic devices is still not completely achieved.

Quality of life and self-esteem for children with urinary urge incontinence and voiding postponement

PURPOSE

Urge incontinence and voiding postponement are common subtypes of daytime wetting in children. We analyzed health related quality of life for children with urge incontinence and voiding postponement, and healthy controls at 2 centers.

MATERIALS AND METHODS

We examined a total of 49 consecutive children 5 to 13 years old who presented with urge incontinence (22) or voiding postponement (27), and 32 controls matched for age and sex. Health related and overall quality of life were measured with generic questionnaires, and self-esteem was measured with the Piers-Harris questionnaire.

RESULTS

Health related quality of life was significantly reduced in parent rating but not in child rating in the incontinent vs control group (total mean parent score 73 vs 78, child 76 vs 76). Children with voiding postponement have the lowest health related quality of life. Overall quality of life was significantly reduced in children with incontinence, while self-esteem did not differ. Children with externalizing disorders generally have the lowest health related and overall quality of life.

CONCLUSIONS

Health related and overall quality of life are useful constructs, and are reduced in children with daytime incontinence by parental rating. In comparison, children rate their quality of life as being higher. Quality of life is lowest with externalizing behavioral disorders, as in children with voiding postponement. Due to comorbid behavioral disturbances, children with voiding postponement often need additional assessment, counseling and treatment.

Otoferlin interacts with myosin VI: implications for maintenance of the basolateral synaptic structure of the inner hair cell

Otoferlin has been proposed to be the Ca(2+) sensor in hair cell exocytosis, compensating for the classical synaptic fusion proteins synaptotagmin-1 and synaptotagmin-2. In the present study, yeast two-hybrid assays reveal myosin VI as a novel otoferlin binding partner. Co-immunoprecipitation assay and co-expression suggest an interaction of both proteins within the basolateral part of inner hair cells (IHCs). Comparison of otoferlin mutants and myosin VI mutant mice indicates non-complementary and complementary roles of myosin VI and otoferlin for synaptic maturation: (i) IHCs from otoferlin mutant mice exhibited a decoupling of CtBP2/RIBEYE and Ca(V)1.3 and severe reduction of exocytosis. (ii) Myosin VI mutant IHCs failed to transport BK channels to the membrane of the apical cell regions, and the exocytotic Ca(2+) efficiency did not mature. (iii) Otoferlin and myosin VI mutant IHCs showed a reduced basolateral synaptic surface area and altered active zone topography. Membrane infoldings in otoferlin mutant IHCs indicated disturbed transport of endocytotic membranes and link the above morphological changes to a complementary role of otoferlin and myosin VI in transport of intracellular compartments to the basolateral IHC membrane.

West Nile virus neuroinvasive disease incidence in the United States, 2002-2006

As the geographic range of reported human West Nile virus (WNV) disease has expanded across the United States, seasonal transmission and outbreaks have persisted over several years in many areas of the country. West Nile virus neuroinvasive disease (WNND) case reports from 2002 to 2006 were reviewed to determine which areas of the country have the highest reported cumulative incidence and whether those areas have had consistently high annual incidence. During the 5-year period examined, 9632 cases of WNND were reported nationwide. The cumulative incidence of WNND ranged from 0.2 to 32.2 per 100,000 population by state and from 0.1 to 241.2 per 100,000 population by county. States and counties with the highest cumulative incidence were primarily located in the northern Great Plains. States with consistently high annual incidence included South Dakota, North Dakota, Wyoming, New Mexico, Mississippi, Nebraska, Louisiana, and Colorado. All of these states, with the exception of New Mexico, were also among the states with the highest cumulative incidence. Counties with repeatedly high annual incidence were also primarily in the Great Plains and mid-South. The risk of WNND appears to be highest in areas where the primary WNV vectors are Culex tarsalis and Cx. quinquefasciatus mosquitoes.

Extending the indications of intramedullary nailing with the Expert Tibial Nail

Numerous modifications in nail and screw design have led to the development of the Expert Tibial Nail. It enables the surgeon to further extend the spectrum of fractures eligible for intramedullary nailing. In the proximal metaphysis spongious bone screws achieve an optimized purchase in the cancellous bone. Multidirectional interlocking screws ensure that alignment can be well maintained and stability preserved in short proximal or distal tibial segments. The end cap achieves angular stability between the proximal oblique screw and the nail. These changes in implant design enhance the stability of the bone-nail construct and reduce the risk for secondary malalignment. The results of our prospective case series demonstrate favorable results and extended indications, compared to standard tibial nails.