The paradox of tPA in ischemic stroke: tPA knockdown following recanalization improves functional and histological outcomes

Previous studies have demonstrated that endogenous tissue-type plasminogen activator (tPA) is upregulated in the brain after an acute ischemic stroke (AIS). While mixed results were observed in genetic models, the pharmacological inhibition of endogenous tPA showed beneficial effects. Treatment with exogenous recombinant tPA exacerbated brain damage in rodent models of stroke. Despite the detrimental effects of tPA in ischemic stroke, recombinant tPA is administered to AIS patients to recanalize the occluded blood vessels because the benefits of its administration outweigh the risks associated with tPA upregulation and increased activity. We hypothesized that tPA knockdown following recanalization would ameliorate sensorimotor deficits and reduce brain injury. Young male and female rats (2-3 months old) were subjected to transient focal cerebral ischemia by occlusion of the right middle cerebral artery. Shortly after reperfusion, rats from appropriate cohorts were administered a nanoparticle formulation containing tPA shRNA or control shRNA plasmids (1 mg/kg) intravenously via the tail vein. Infarct volume during acute and chronic phases, expression of matrix metalloproteinases (MMPs) 1, 3, and 9, enlargement of cerebral ventricle volume, and white matter damage were all reduced by shRNA-mediated gene silencing of tPA following reperfusion. Additionally, recovery of somatosensory and motor functions was improved. In conclusion, our results provide evidence that reducing endogenous tPA following recanalization improves functional outcomes and reduces post-stroke brain damage.

Neurotropin® accelerates peripheral nerve regeneration in a rat sciatic nerve crush injury model

BACKGROUND

Peripheral nerve injuries are common and serious conditions. The effect of Neurotropin® (NTP), a nonprotein extract derived from the inflamed skin of rabbits inoculated with vaccinia virus, on peripheral nerve regeneration has not been fully elucidated. However, it has analgesic properties via the activation of descending pain inhibitory systems. Therefore, the current study aimed to determine the effects of NTP on peripheral nerve regeneration.

METHODS

We examined axonal outgrowth of dorsal root ganglion (DRG) neurons using immunocytochemistry in vitro. In addition, nerve regeneration was evaluated functionally, electrophysiologically, and histologically in a rat sciatic nerve crush injury model in vivo. Furthermore, gene expression of neurotrophic factors in the injured sciatic nerves and DRGs was evaluated.

RESULTS

In the dorsal root ganglion neurons in vitro, NTP promoted axonal outgrowth at a concentration of 10 mNU/mL. Moreover, the systemic administration of NTP contributed to the recovery of motor and sensory function at 2 weeks, and of sensory function, nerve conduction velocity, terminal latency, and axon-remyelination 4 weeks after sciatic nerve injury. In the gene expression assessment, insulin-like growth factor 1 and vascular endothelial growth factor expressions were increased in the injured sciatic nerve 2 days postoperatively.

CONCLUSIONS

Therefore, NTP might be effective in not only treating chronic pain but also promoting peripheral nerve regeneration after injury.

Skin Innervation

All layers and appendages of the skin are densely innervated by afferent and efferent neurons providing sensory information and controlling skin perfusion and sweating. In mice, neuronal functions have been comprehensively linked to unique single-cell expression patterns and to characteristic arborization of nerve endings in skin and dorsal horn, whereas for humans, specific molecular markers for functional classes of afferent neurons are still lacking. Moreover, bidirectional communication between sensory neurons and local skin cells has become of particular interest, resulting in a broader physiological understanding of sensory function but also of trophic functions and immunomodulation in disease states.

Marital dissatisfaction and functional performance in older adults: Heterogeneity in the association by educational level

RATIONALE

The marital relationship is an important source of the well-being of older adults. Despite existing literature on marital dissatisfaction and adverse health outcomes, little is known about whether marital dissatisfaction is associated with functional performance in older adults.

OBJECTIVE

Drawing on stress process model and health behavior model, this study examined the longitudinal association between marital dissatisfaction and older adults' functional performance. Furthermore, we sought to investigate whether this association varies based on educational level.

METHODS

Using seven waves (12 years) of the Korean Longitudinal Study of Ageing (KLoSA) from 2006 to 2019, this study estimated fixed effects models to account for unobserved individual-level confounders. Objectively measured hand grip strength and subjective assessments of vision, hearing, masticatory functions, as well as limitations in activities of daily living (ADLs) and instrumental activities of daily living (IADLs) were used to evaluate functional performance. An interaction model was used to determine whether educational level moderates the association.

RESULTS

Fixed effects estimates revealed that marital dissatisfaction is negatively associated with grip strength, as well as masticatory, vision, and hearing functions, while also showing a positive association with limitations in ADLs and IADLs. The results of this study provided evidence on heterogeneity in the association by educational level. The associations between marital dissatisfaction and functional performance, including grip strength, mastication, and hearing, were driven primarily by those with older adults with a higher level of education.

CONCLUSION

The findings of this study suggest that marital dissatisfaction is a robust predictor of functional performance in older adults. Efforts to address marital dissatisfaction has the potential to improve functional performance, particularly for older adults with higher levels of education.

Sex differences in vision and hearing impairments across age and European regions : Findings from SHARE

AIM

Although sensory impairments are common conditions among older people, research often fails to consider the role of sex. We examined sex differences in vision impairment and hearing impairment across age and European regions.

METHODS

We conducted a cross-sectional study based on a pooled sample of 65,656 females and 54,881 males aged 50 years and older participating in the Survey of Health, Ageing and Retirement in Europe (SHARE) from 2004-2020. Logistic regression models with robust standard errors providing odds ratios (OR) and 95% confidence intervals (CI) were used to examine associations.

RESULTS

European females had generally higher odds of vision impairment (OR 1.16, 95% CI 1.12-1.21) but lower odds of hearing impairment than European males (OR 0.70, 95% CI 0.67-0.73). The female disadvantage in vision increased with advancing age, whereas the female advantage in hearing decreased. No overall sex difference in vision was found in northern Europe, but females had more vision impairments than males in southern (OR 1.23, 95% CI 1.14-1.32), western (OR 1.14, 95% CI 1.08-1.21) and eastern (OR 1.10, 95% CI 1.02-1.20) Europe. Females were healthier than males in terms of hearing in all regions, with the largest female advantage in northern Europe (OR 0.58, 95% CI 0.53-0.64).

CONCLUSION

Our findings demonstrate an overall consistent pattern of sex differences in sensory impairments across Europe showing an increasing female disadvantage in vision and a decreasing female advantage in hearing with advancing age.

Sensory phenotypes in complex regional pain syndrome and chronic low back pain-indication of common underlying pathomechanisms

Introduction

First-line pain treatment is unsatisfactory in more than 50% of chronic pain patients, likely because of the heterogeneity of mechanisms underlying pain chronification.

Objectives

This cross-sectional study aimed to better understand pathomechanisms across different chronic pain cohorts, regardless of their diagnoses, by identifying distinct sensory phenotypes through a cluster analysis.

Methods

We recruited 81 chronic pain patients and 63 age-matched and sex-matched healthy controls (HC). Two distinct chronic pain cohorts were recruited, ie, complex regional pain syndrome (N = 20) and low back pain (N = 61). Quantitative sensory testing (QST) was performed in the most painful body area to investigate somatosensory changes related to clinical pain. Furthermore, QST was conducted in a pain-free area to identify remote sensory alterations, indicating more widespread changes in somatosensory processing.

Results

Two clusters were identified based on the QST measures in the painful area, which did not represent the 2 distinct pain diagnoses but contained patients from both cohorts. Cluster 1 showed increased pain sensitivities in the painful and control area, indicating central sensitization as a potential pathomechanism. Cluster 2 showed a similar sensory profile as HC in both tested areas. Hence, either QST was not sensitive enough and more objective measures are needed to detect sensitization within the nociceptive neuraxis or cluster 2 may not have pain primarily because of sensitization, but other factors such as psychosocial ones are involved.

Conclusion

These findings support the notion of shared pathomechanisms irrespective of the pain diagnosis. Conversely, different mechanisms might contribute to the pain of patients with the same diagnosis.

Semi-occlusive dressing versus surgery in fingertip injuries: A randomized controlled trial

OBJECTIVES

No gold-standard treatment has been established for the management of distal digital amputation in Ishikawa zones II and III. The objective of this study was to compare the results of management of fingertip amputation by semi-occlusive dressing versus surgery. The principal hypothesis was that a semi-occlusive dressing results in better recovery of sensory function than a digital flap.

METHODS

We conducted a prospective, randomized, multicenter study of 44 patients: 23 managed conservatively with semi-occlusive dressing, and 21 surgically with digital flap.

RESULTS

Mean follow-up was 12 months. Mean healing time was 4.9 weeks in the semi-occlusive dressing group and 3.6 weeks in the surgery group. There was no significant difference between groups for sensory recovery of fine touch (p = 0.198) or 2-point discrimination (p = 0.961). No infections were reported in either group. Hook-nail deformity was more frequent in the semi-occlusive dressing group, particularly in case of amputation in zone III.

CONCLUSIONS

Semi-occlusive dressing enabled satisfactory healing and sensitivity recovery without increasing the risk of infection. However, in zone III amputation, we advocate surgical treatment with a digital flap, due to poor trophicity and the frequency of hook-nail deformity seen with conservative management.

LEVEL OF EVIDENCE

II.

Aquaporin 4 beyond a water channel; participation in motor, sensory, cognitive and psychological performances, a comprehensive review

Aquaporin 4 (AQP4) is a protein highly expressed in the central nervous system (CNS) and peripheral nervous system (PNS) as well as various other organs, whose different sites of action indicate its importance in various functions. AQP4 has a variety of essential roles beyond water homeostasis. In this article, we have for the first time summarized different roles of AQP4 in motor and sensory functions, besides cognitive and psychological performances, and most importantly, possible physiological mechanisms by which AQP4 can exert its effects. Furthermore, we demonstrated that AQP4 participates in pathology of different neurological disorders, various effects depending on the disease type. Since neurological diseases involve a spectrum of dysfunctions and due to the difficulty of obtaining a treatment that can simultaneously affect these deficits, it is therefore suggested that future studies consider the role of this protein in different functional impairments related to neurological disorders simultaneously or separately by targeting AQP4 expression and/or polarity modulation.

Long-term efficacy of high-frequency (10 kHz) spinal cord stimulation for the treatment of painful diabetic neuropathy: 24-Month results of a randomized controlled trial

AIMS

To evaluate the long-term efficacy of high-frequency (10 kHz) spinal cord stimulation (SCS) for treating refractory painful diabetic neuropathy (PDN).

METHODS

The SENZA-PDN study was a prospective, multicenter, randomized controlled trial that compared conventional medical management (CMM) alone with 10 kHz SCS plus CMM (10 kHz SCS+CMM) in 216 patients with refractory PDN. After 6 months, participants with insufficient pain relief could cross over to the other treatment. In total, 142 patients with a 10 kHz SCS system were followed for 24 months, including 84 initial 10 kHz SCS+CMM recipients and 58 crossovers from CMM alone. Assessments included pain intensity, health-related quality of life (HRQoL), sleep, and neurological function. Investigators assessed neurological function via sensory, reflex, and motor tests. They identified a clinically meaningful improvement relative to the baseline assessment if there was a significant persistent improvement in neurological function that impacted the participant's well-being and was attributable to a neurological finding.

RESULTS

At 24 months, 10 kHz SCS reduced pain by a mean of 79.9% compared to baseline, with 90.1% of participants experiencing ≥50% pain relief. Participants had significantly improved HRQoL and sleep, and 65.7% demonstrated clinically meaningful neurological improvement. Five (3.2%) SCS systems were explanted due to infection.

CONCLUSIONS

Over 24 months, 10 kHz SCS provided durable pain relief and significant improvements in HRQoL and sleep. Furthermore, the majority of participants demonstrated neurological improvement. These long-term data support 10 kHz SCS as a safe and highly effective therapy for PDN.

TRIAL REGISTRATION

ClincalTrials.gov Identifier, NCT03228420.

Why Are Old-Age Disabilities Decreasing in Sweden and Denmark? Evidence on the Contribution of Cognition, Education, and Sensory Functions

OBJECTIVES

Improvements in educational attainment, cognitive and sensory functions, and a decline in the prevalence of disabilities have been observed in older adults in Sweden and Denmark. In the present study, it was investigated whether better cognition, higher educational attainment, and improved sensory function among older adults aged 60 and older in these countries have contributed to decreasing rates of old-age disabilities.

METHODS

The analyses were based on repeated cross-sectional data from the Survey of Health, Ageing, and Retirement in Europe for the 2004-2017 period. Descriptive data were used to benchmark the declining prevalence of disabilities, improving cognitive and sensory functions, and increased educational level. The association between time and disabilities was analyzed with logistic regression models, and the contribution of the improved cognitive function, education, and sensory function to the declining prevalence of old-age disabilities was estimated using the Karlson-Holm-Breen method for mediation analysis.

RESULTS

The analysis suggests that the declining prevalence of old-age disabilities in Sweden and Denmark between 2004 and 2017 can largely be attributed to improved cognitive function and vision and to a lesser extent by education and hearing ability.

DISCUSSION

These findings raise important questions about the causal mechanisms producing the associations between cognition, education, and sensory functions and disability in older age. Future studies should explore the causal nature of the associations between these mediators and old-age disabilities. In addition, they should explore whether these findings differ across regional and cultural contexts and over different time periods.

Cardiac autonomic neuropathy predicts diabetic retinopathy progression in Asian population with type 2 diabetes mellitus

PURPOSE

To investigate the role of cardiac autonomic neuropathy (CAN), vascular condition, and sensory function in diabetic retinopathy (DR) progression.

METHODS

This 3-year cohort study conducted in a community hospital included 4850 patients over 20 with type 2 diabetes mellitus. Participants were assessed in 2017 at baseline and were followed up in 2020. Patients were divided into two groups based on whether they had DR progression or not and were compared using the chi-square test or two-sample t-test. Beta coefficient and odds ratio (OR) with 95% confidence intervals were calculated using binary logistic regression. The receiver operating characteristic (ROC) curve of various independent variables for DR progression was provided with C-statistics.

RESULTS

Abnormal hemoglobin A1c (HbA1c) level/variation, estimated glomerular filtration rate, urine albumin-to-creatinine ratio, R-R interval variation, standard deviation of the average NN intervals, autonomic nervous system function, power of high-frequency (HF) bands, balance, cardio-ankle vascular index (CAVI), and warm stimulation (WS) were associated with DR progression. Average HbA1c, HF, and proliferative diabetic retinopathy were independent factors for patients developing DR progression. The top three areas under the curve of ROCs were HF + baseline DR grading, WS + baseline DR grading, and CAVI + baseline DR grading. These variable combinations were the most reliable predictors of DR progression.

CONCLUSION

CAN, abnormal vascular condition, and sensory function are associated with DR progression. The combination of HF, WS, and CAVI with baseline DR grading provides the most accurate predictive model for DR progression. Early detection of these factors is important to prevent DR progression.

A modified Bilhaut-Cloquet procedure for thumb duplication: Reconstruction of functionality and appearance

BACKGROUND

The Bilhaut-Cloquet technique is the preferred surgical method for thumb polydactyly with symmetrical caliber and osseous components. However, the traditional Bilhaut-Cloquet technique has many esthetic and functional complications. In this study, we aimed to investigate an effective modified Bilhaut-Cloquet procedure for Wassel type IV thumb duplication.

METHODS

The dorsal scar of the thumb was hidden on the ulnar side of the thumb through the flap design. The nail bed was sutured flat by combining the phalangeal bone and nail bed on different planes. The sensory function of the thumb was restored by keeping the ulnar skin of the thumb intact.

RESULTS

Our modified Bilhaut-Cloquet procedure did not reduce the mobility of the joints. All patients had relatively rounded fingernails, and no seagull deformity was present. The ulnar side of the palm skin of the thumb remained intact with no scars, maximizing the preservation of the sensory function of the thumb. All the operated children and their parents were satisfied with the esthetic result.

CONCLUSIONS

We hid the surgical scar by improving the surgical method and reducing the thumb seagull nail deformity, and the influencing of the finger sensation caused by the scar on the finger abdomen. The procedure improved not only the appearance of the reconstructed thumbs but also the sensory function of the thumbs.

Somatosensory Plasticity in Hemiplegic Cerebral Palsy Following Constraint Induced Movement Therapy

BACKGROUND

Children with hemiplegic cerebral palsy (HCP) experience upper limb somatosensory and motor deficits. Although constraint-induced movement therapy (CIMT) improves motor function, its impact on somatosensory function remains underinvestigated.

OBJECTIVE

The objective of this study was to evaluate somatosensory perception and related brain responses in children with HCP, before and after a somatosensory enhanced CIMT protocol, as measured using clinical sensory and motor assessments and magnetoencephalography.

METHODS

Children with HCP attended a somatosensory enhanced CIMT camp. Clinical somatosensory (tactile registration, 2-point discrimination, stereognosis, proprioception, kinesthesia) and motor outcomes (Quality of Upper Extremity Skills [QUEST] Total/Grasp, Jebsen-Taylor Hand Function Test, grip strength, Assisting Hand Assessment), as well as latency and amplitude of magnetoencephalography somatosensory evoked fields (SEF), were assessed before and after the CIMT camp with paired sample t-tests or Wilcoxon signed-rank tests.

RESULTS

Twelve children with HCP (mean age: 7.5 years, standard deviation: 2.4) participated. Significant improvements in tactile registration for the affected (hemiplegic) hand (Z = 2.39, P = 0.02) were observed in addition to statistically and clinically significant improvements in QUEST total (t = 3.24, P = 0.007), QUEST grasp (t = 3.24, P = 0.007), Assisting Hand Assessment (Z = 2.25, P = 0.03), and Jebsen-Taylor Hand Function Test (t = -2.62, P = 0.03). A significant increase in the SEF peak amplitude was also found in the affected hand 100 ms after stimulus onset (t = -2.22, P = 0.04).

CONCLUSIONS

Improvements in somatosensory clinical function and neural processing in the affected primary somatosensory cortex in children with HCP were observed after a somatosensory enhanced CIMT program. Further investigation is warranted to continue to evaluate the effectiveness of a sensory enhanced CIMT program in larger samples and controlled study designs.

Stem cell, Granulocyte-Colony Stimulating Factor and/or Dihexa to promote limb function recovery in a rat sciatic nerve damage-repair model: Experimental animal studies

Background

Optimizing nerve regeneration and re-innervation of target muscle/s is the key for improved functional recovery following peripheral nerve damage. We investigated whether administration of mesenchymal stem cell (MSC), Granulocyte-Colony Stimulating Factor (G-CSF) and/or Dihexa can improve recovery of limb function following peripheral nerve damage in rat sciatic nerve transection-repair model.

Materials and methods

There were 10 experimental groups (n = 6–8 rats/group). Bone marrow derived syngeneic MSCs (2 × 10⁶; passage≤6), G-CSF (200–400 μg/kg b.wt.), Dihexa (2–4 mg/kg b.wt.) and/or Vehicle were administered to male Lewis rats locally via hydrogel at the site of nerve repair, systemically (i.v./i.p), and/or to gastrocnemius muscle. The limb sensory and motor functions were assessed at 1–2 week intervals post nerve repair until the study endpoint (16 weeks).

Results

The sensory function in all nerve boundaries (peroneal, tibial, sural) returned to nearly normal by 8 weeks (Grade 2.7 on a scale of Grade 0–3 [0 = No function; 3 = Normal function]) in all groups combined. The peroneal nerve function recovered quickly with return of function at one week (∼2.0) while sural nerve function recovered rather slowly at four weeks (∼1.0). Motor function at 8–16 weeks post-nerve repair as determined by walking foot print grades significantly (P < 0.05) improved with MSC + G-CSF or MSC + Dihexa administrations into gastrocnemius muscle and mitigated foot flexion contractures.

Conclusions

These findings demonstrate MSC, G-CSF and Dihexa are promising candidates for adjunct therapies to promote limb functional recovery after surgical nerve repair, and have implications in peripheral nerve injury and limb transplantation. IACUC No.215064.

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G-CSF in combination with MSCs improved limb function recovery in sciatic nerve transection- repair model.

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Dihexa in combination with MSC improved limb function recovery in sciatic nerve transection- repair model.

•

Foot flexion contractures were reduced with G-CSF & MSC or Dihexa & MSC administration into target muscle gastrocnemius.

•

MSC, G-CSF or Dihexa combination therapy is attractive, feasible & promising in peripheral nerve injury repair and have implications in limb transplantation.

•

The findings warrant further investigation to understand the cellular/molecular mechanisms.

Caenorhabditis elegans exhibits positive gravitaxis

BACKGROUND

Gravity plays an important role in most life forms on Earth. Yet, a complete molecular understanding of sensing and responding to gravity is lacking. While there are anatomical differences among animals, there is a remarkable conservation across phylogeny at the molecular level. Caenorhabditis elegans is suitable for gene discovery approaches that may help identify molecular mechanisms of gravity sensing. It is unknown whether C. elegans can sense the direction of gravity.

RESULTS

In aqueous solutions, motile C. elegans nematodes align their swimming direction with the gravity vector direction while immobile worms do not. The worms orient downward regardless of whether they are suspended in a solution less dense (downward sedimentation) or denser (upward sedimentation) than themselves. Gravitaxis is minimally affected by the animals' gait but requires sensory cilia and dopamine neurotransmission, as well as motility; it does not require genes that function in the body touch response.

CONCLUSIONS

Gravitaxis is not mediated by passive forces such as non-uniform mass distribution or hydrodynamic effects. Rather, it is mediated by active neural processes that involve sensory cilia and dopamine. C. elegans provides a genetically tractable system to study molecular and neural mechanisms of gravity sensing.

Sensory signs and symptoms in women with self-reported breast cancer-related lymphedema: a case-control study close up

PURPOSE

It is not clear to what extent signs and symptoms other than arm swelling, including pain, altered sensory function, and body perception disturbances, differ between women with measurable and non-measurable breast cancer-related lymphedema (BCRL). A case-control study was performed to compare these signs and symptoms between (1) women with self-reported BCRL with objectively measurable swelling; (2) women with self-reported BCRL without objective confirmation; and (3) a control group with no self-reported BCRL.

METHODS

The three groups were compared for (1) the severity of self-reported signs and symptoms of BCRL, (2) problems in functioning related to BCRL, (3) pain-related outcomes, (4) sensory functions, and (5) body perception.

RESULTS

All self-reported outcomes related to signs and symptoms of BCRL and problems in functioning were significantly different between the control group and the other two groups with and without measurable self-reported BCRL (p < 0.001-0.003). Except for "skin texture" (p = 0.01), no differences were found between groups. For pain-related outcomes, sensory function, and body perception, significant differences were found for the mechanical detection threshold (p < 0.01) and self-reported disturbances in body perception (p < 0.001) between the self-reported BCRL groups and control group.

CONCLUSIONS

Diverse signs and symptoms related to BCRL, sensory function, and perception were different among women with self-reported BCRL compared to controls. No differences between women with and without measurable self-reported BCRL were found.

IMPLICATIONS FOR CANCER SURVIVORS

The presence of self-reported BCRL, with or without measurable swelling, is a first indication for the need of further diagnostic evaluation.

Vibration Perception Threshold and Heart Rate Variability as methods to assess chemotherapy-induced neuropathy in women with breast cancer - a pilot study

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is a recognized adverse effect of standard (neo)adjuvant chemotherapy in breast cancer (BC) treatment. However, there is no consensus on a validated method for assessing CIPN. Heart rate variability (HRV) and vibration perception threshold (VPT) could be used as objective measures to describe CIPN. The aim of this pilot study was to investigate whether subjectively reported CIPN was associated with altered HRV and VPT in BC patients.

METHODS

We performed a cross-sectional pilot study evaluating 30 BCE patients previously treated with chemotherapy, 26 BCE patients who did not receive chemotherapy, and 22 controls without breast cancer. Self-reported CIPN was registered for the BC patients. All participants were subjected to multi-frequency vibration analyses to determine VPT along with short ECG measurements to determine HRV measures.

RESULTS

Self-reported CIPN was registered in 14 (46.6%) BC patients treated with chemotherapy. The VPT at 64 Hz (P = 0.022) and mean HR (P = 0.022) were significantly higher and the HRV measures SDNN (P = 0.023), RMSSD (P = 0.007), LF (P = 0.050) and HF (P = 0.045) were significantly lower in BC patients reporting CIPN compared to controls when adjusted for age. VPT at 64 Hz and 125 Hz were significantly higher in BC patients not reporting CIPN compared to controls when adjusted for age.

CONCLUSION

We found elevated VPT and mean HR along with decreased HRV parameters in 14 BCE patients reporting CIPN. These findings support the need for further investigation into whether HRV and vibration analysis could contribute to an objective assessment of CIPN.

Effects of tactile stimulation on the sensory, motor and cognitive function in people with multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease that causes demyelination in the brain and spinal cord. Repetitive sensory stimulation (RSS) can enhance sensory perception and motor function, improve inappropriate synaptic connections and adaptable malformations, and increase cognitive function. The purpose of this study was to specify the effect of RSS on the sensory, motor, and cognitive function in people with MS.

METHODS

RSS was applied to 50 people with MS. In this study, the following tests were used: two-point discrimination, 9-Hole Peg Test (9-HPT), Box and Block Test (BBT), hand mental rotation (HMR), Paced Auditory Serial Addition Test (PASAT), and Symbol Digit Modalities Test (SDMT). The tests were performed before and after the intervention.

RESULTS

The results of this study showed significant difference before and after the stimulation in intervention and control groups two-point discrimination threshold (both groups= 0.001), BBT score (both groups: P < 0.001) and 9-HPT score (both groups: P < 0.001), HMR ability (reaction time: both groups: P = 0.003; accuracy rate: intervention: P = 0.004, control: P < 0.001), PASAT score (intervention: P < 0.001, control: P = 0.012) and SDMT score (intervention: P = 0.008, control: P < 0.001), but there was no statistical difference observed between the two groups before and after the intervention in terms of the mentioned variables (P > 0.05).

CONCLUSION

The application of 30 min of RSS in the right index finger of people with MS could not improve the two-point discrimination threshold and the manual dexterity. In addition, this intervention did not improve cognitive function.

Attenuation of the Induction of TLRs 2 and 4 Mitigates Inflammation and Promotes Neurological Recovery After Focal Cerebral Ischemia

The intense inflammatory response triggered in the brain after focal cerebral ischemia is detrimental. Recently, we showed that the suppression of toll-like receptors (TLRs) 2 and 4 attenuates infarct size and reduces the expression of pro-inflammatory cytokines in the ischemic brain. In this study, we further examined the effect of unsuppressed induction of TLRs 2 and 4 on the expression of its downstream signaling molecules and pro-inflammatory cytokines 1 week after reperfusion. The primary purpose of this study was to investigate the effect of simultaneous knockdown of TLRs 2 and 4 on M1/M2 microglial polarization dynamics and post-stroke neurological deficits and the recovery. Transient focal cerebral ischemia was induced in young adult male Sprague-Dawley rats by the middle cerebral artery occlusion (MCAO) procedure using a monofilament suture. Appropriate cohorts of rats were treated with a nanoparticle formulation of TLR2shRNA and TLR4shRNA (T2sh+T4sh) expressing plasmids (1 mg/kg each of T2sh and T4sh) or scrambled sequence inserted vector (vehicle control) expressing plasmids (2 mg/kg) intravenously via tail vein immediately after reperfusion. Animals from various cohorts were euthanized during reperfusion, and the ischemic brain tissue was isolated and utilized for PCR followed by agarose gel electrophoresis, real-time PCR, immunoblot, and immunofluorescence analysis. Appropriate groups were subjected to a battery of standard neurological tests at regular intervals until 14 days after reperfusion. The increased expression of both TLRs 2 and 4 and their downstream signaling molecules including the pro-inflammatory cytokines was observed even at 1-week after reperfusion. T2sh+T4sh treatment immediately after reperfusion attenuated the post-ischemic inflammation, preserved the motor function, and promoted recovery of the sensory and motor functions. We conclude that the post-ischemic induction of TLRs 2 and 4 persists for at least 7 days after reperfusion, contributes to the severity of acute inflammation, and impedes neurological recovery. Unlike previous studies in TLRs 2 or 4 knockout models, results of this study in a pharmacologically relevant preclinical rodent stroke model have translational significance.

Association of disease duration and sensorimotor function in type 2 diabetes mellitus: beyond diabetic peripheral neuropathy

PURPOSE

The aim of the study is to assess association of the duration of diabetes and vibration, proprioception, muscle strength, reaction time and balance measures in people with type 2 diabetes mellitus (DM) without peripheral neuropathy.

METHODS

Forty-seven type 2 diabetics without peripheral neuropathy and 23 healthy controls were recruited for the study. Patients with type 2 DM were further classified into 23 patients who suffered from diabetes for less than 5 years (<5yrDM) and 24 patients who had diabetes for 5 years and above (≥5yrDM). All participants were assessed for Michigan neuropathy screening instrument (MNSI), vibration perception threshold (VPT), proprioception, muscles strength, centre of pressure (COP) range, COP sway and reaction time.

RESULTS

≥5yrDM patients were found to significantly differ from healthy control in MNSI score (p ≤ 0.013), VPT score (p ≤ 0.002), reaction time (p ≤ 0.018), COP range (p ≤ 0.005) and COP sway (p ≤ 0.027). A significant difference was found only in reaction time (p < 0.002) except in the back direction (p = 0.089), and COP range (p ≤ 0.016) except in the front (p = 0.101) and right direction (p = 0.085) between <5yrDM patients and healthy controls.

CONCLUSIONS

≥5yrDM patients exhibit a subtle deterioration in VPT, reaction time, and balance measure while <5yr DM patients were impaired only in COP range and reaction time when compared with healthy control.

Assessing the spatial distribution of cervical spinal cord activity during tactile stimulation of the upper extremity in humans with functional magnetic resonance imaging

Dermatomal maps are a mainstay of clinical practice and provide information on the spatial distribution of the cutaneous innervation of spinal nerves. Dermatomal deficits can help isolate the level of spinal nerve root involvement in spinal conditions and guide clinicians in diagnosis and treatment. Dermatomal maps, however, have limitations, and the spatial distribution of spinal cord sensory activity in humans remains to be quantitatively assessed. Here we used spinal cord functional MRI to map and quantitatively compare the spatial distribution of sensory spinal cord activity during tactile stimulation of the left and right lateral shoulders (i.e. C5 dermatome) and dorsal third digits of the hands (i.e., C7 dermatome) in healthy humans (n = 24, age = 36.8 ± 11.8 years). Based on the central sites for processing of innocuous tactile sensory information, we hypothesized that the activity would be localized more to the ipsilateral dorsal spinal cord with the lateral shoulder stimulation activity being localized more superiorly than the dorsal third digit. The findings demonstrate lateralization of the activity with the left- and right-sided stimuli having more activation in the ipsilateral hemicord. Contradictory to our hypotheses, the activity for both stimulation sites was spread across the dorsal and ventral hemicords and did not demonstrate a clear superior-inferior localization. Instead, the activity for both stimuli had a broader than expected distribution, extending across the C5, C6, and C7 spinal cord segments. We highlight the complexity of the human spinal cord neuroanatomy and several sources of variability that may explain the observed patterns of activity. While the findings were not completely consistent with our a priori hypotheses, this study provides a foundation for continued work and is an important step towards developing normative quantitative spinal cord measures of sensory function, which may become useful objective MRI-based biomarkers of neurological injury and improve the management of spinal disorders.

Shape-texture-identification-STI-A test for tactile gnosis: Concurrent validity of STI(2)

STUDY DESIGN

Cross-sectional study.

INTRODUCTION

The shape-texture-identification (STI) test (Össur Nordic AB, Sweden) is used to evaluate one aspect of tactile gnosis in nerve disorders, and it has proven good methodological properties.

PURPOSE OF THE STUDY

A new version of the STI test was recently introduced-STI² (www.sensory-test.com). The purpose of this study was to test the concurrent validity in STI².

METHODS

Using a cross-sectional design, this methodological study compared STI² to the original version based on 2 cohorts; 1 including 20 persons (1 affected finger and corresponding finger on in opposite hand) with affected sensibility after hand injuries and 1 healthy group including 20 persons (digits II and V in both hands). The agreement between the 2 versions of the instrument was calculated statistically by a percentage comparison of the test results and weighted kappa.

RESULTS

The 112 tested fingers showed a complete agreement, or 1-point accepted deviation, between the 2 tests in 92% with weighted kappa of 0.74 and 95% confidence interval of 0.63-0.89. The result showed that there is no significant deviation between the 2 versions of the test.

DISCUSSION

The use of standardizes and evidence based assessment tools in clinical practice is paramount for a patient centered healthcare. Previous research has shown good psychometric proprties in the STI-test. This study contributes to the scientific evidence of the instrument.

CONCLUSION

As the new STI² proved good agreement within the accepted deviation, we conclude that there is evidence to use the new STI² test in assessment of tactile gnosis.

Strategies for Behaviorally Phenotyping the Transgenic Mouse

The techniques and protocols to modify the mouse genome described in this volume allow researchers to produce genetic models of a remarkable number and breadth of human disease. The generation of gene-modified mice offers profoundly powerful approaches for bringing known or purported human gene disruptions into mouse models, but the degree to which the resultant mutant mouse recapitulates the complex physiological and behavioral features of the human disease state is a key variable in the ultimate usefulness of the mouse model organism. Accordingly, the behavioral characterization of mice with novel targeted gene mutations is an important initial step in determining the potential impact of a novel mouse model. This chapter addresses strategies useful in the initial observations of the animal that assist in directing the choice of secondary tests to assess more detailed aspects of potentially disrupted behaviors that may be relevant to the disease being modeled. An initial standardized, comprehensive screen that assesses general health, reflexes, and sensorimotor functions is the first step in characterizing behavioral phenotype, and results often suggest areas where more complex complementary behavioral assays may reveal more detailed disruption of normal behavior. This sequential, standardized approach reduces variability between subjects; this chapter also addresses approaches to reducing experimental artifacts due to handling, test order, testing facility environment, and other sources. This brief overview of behavioral phenotyping approaches is intended to provide practical information to streamline initial characterization of new mouse models and maximize the usefulness of efforts to use these models to study human health and disease.

Replantation at the level of the wrist joint: A case report

Upper extremities amputations are devastating injuries that have a major impact on patients' quality of life. Replantation after traumatic amputation is often performed to obtain limb recovery. Following the high survival rate of replantation of post-traumatic hand amputation, recent emphasis has now shifted to functional recovery rather than survival only. Wrist replantation remains a challenging procedure for orthopaedic and hand surgeon. We reported a case of a 25-year-old male with traumatic amputation of the right hand.

Randomized controlled trial protocol to improve multisensory neural processing, language and motor outcomes in preterm infants

BACKGROUND

Premature infants are at risk for abnormal sensory development due to brain immaturity at birth and atypical early sensory experiences in the Neonatal Intensive Care Unit. This altered sensory development can have downstream effects on other more complex developmental processes. There are currently no interventions that address rehabilitation of sensory function in the neonatal period.

METHODS

This study is a randomized controlled trial of preterm infants enrolled at 32-36 weeks postmenstrual age to either standard care or standard care plus multisensory intervention in order to study the effect of multisensory intervention as compared to standard care alone. The study population will consist of 100 preterm infants in each group (total n = 200). Both groups will receive standard care, consisting of non-contingent recorded parent's voice and skin-to-skin by parent. The multisensory group will also receive contemporaneous holding and light pressure containment for tactile stimulation, playing of the mother's voice contingent on the infant's pacifier sucking for auditory stimulation, exposure to a parent-scented cloth for olfactory stimulation, and exposure to carefully regulated therapist breathing that is mindful and responsive to the child's condition for vestibular stimulation. The primary outcome is a brain-based measure of multisensory processing, measured using time locked-EEG. Secondary outcomes include sensory adaptation, tactile processing, speech sound differentiation, motor and language function, measured at one and two years corrected gestational age.

DISCUSSION

This is the first randomized controlled trial of a multisensory intervention using brain-based measurements in order to explain the causal effects of the multisensory intervention on neural processing changes to mediate neurodevelopmental outcomes in former preterm infants. In addition to contributing a critical link in our understanding of these processes, the protocolized multisensory intervention in this study is therapist administered, parent supported and leverages simple technology. Thus, this multisensory intervention has the potential to be widely implemented in various NICU settings, with the opportunity to potentially improve neurodevelopment of premature infants.

TRIAL REGISTRATION

NIH Clinical Trials ( clinicaltrials.gov ): NCT03232931 . Registered July 2017.

Evaluation of muscle strength and manual dexterity in patients with Charcot-Marie-Tooth disease

STUDY DESIGN

Matched pair study.

INTRODUCTION

Differences in hand-muscle strength/dexterity between dominant (DH) and non-dominant (NDH) hand in Charcot-Marie-Tooth disease (CMT) are not well understood.

PURPOSE OF THE STUDY

To compare muscle strength/dexterity between DH and NDH and to correlate manual dexterity, strength and sensory function.

PATIENTS AND METHODS

Thirty CMT patients were studied using functional muscle testing (FMT) and strength (dynamometry), dexterity (the Nine Hole Peg Test [NHPT]), and Jebsen-Taylor Hand Function [JTT]), and sensory function (the Nottingham Sensory Assessment [NSA]).

RESULTS

Scores were worse for DH than NDH on FMT (p = 0.043) and NHPT (p = 0.014) but not on JTT (p = 0.098), handgrip strength (p = 0.710) or tripod pinch (p = 0.645). NSA did not correlate significantly with any tests (p's0.05).

CONCLUSIONS

In CMT disease, DH appears more impaired than NDH in terms of function and dexterity. Greater muscle weakness in DH may also emerge as CMT progresses.

LEVEL OF EVIDENCE

3b.

Functional magnetic resonance imaging of the cervical spinal cord during thermal stimulation across consecutive runs

The spinal cord is the first site of nociceptive processing in the central nervous system and has a role in the development and perpetuation of clinical pain states. Advancements in functional magnetic resonance imaging are providing a means to non-invasively measure spinal cord function, and functional magnetic resonance imaging may provide an objective method to study spinal cord nociceptive processing in humans. In this study, we tested the validity and reliability of functional magnetic resonance imaging using a selective field-of-view gradient-echo echo-planar-imaging sequence to detect activity induced blood oxygenation level-dependent signal changes in the cervical spinal cord of healthy volunteers during warm and painful thermal stimulation across consecutive runs. At the group and subject level, the activity was localized more to the dorsal hemicord, the spatial extent and magnitude of the activity was greater for the painful stimulus than the warm stimulus, and the spatial extent and magnitude of the activity exceeded that of a control analysis. Furthermore, the spatial extent of the activity for the painful stimuli increased across the runs likely reflecting sensitization. Overall, the spatial localization of the activity varied considerably across the runs, but despite this variability, a machine-learning algorithm was able to successfully decode the stimuli in the spinal cord based on the distributed pattern of the activity. In conclusion, we were able to successfully detect and characterize cervical spinal cord activity during thermal stimulation at the group and subject level.

Drosophila melanogaster as a model for basal body research

The fruit fly, Drosophila melanogaster, is one of the most extensively studied organisms in biological research and has centrioles/basal bodies and cilia that can be modelled to investigate their functions in animals generally. Centrioles are nine-fold symmetrical microtubule-based cylindrical structures required to form centrosomes and also to nucleate the formation of cilia and flagella. When they function to template cilia, centrioles transition into basal bodies. The fruit fly has various types of basal bodies and cilia, which are needed for sensory neuron and sperm function. Genetics, cell biology and behaviour studies in the fruit fly have unveiled new basal body components and revealed different modes of assembly and functions of basal bodies that are conserved in many other organisms, including human, green algae and plasmodium. Here we describe the various basal bodies of Drosophila, what is known about their composition, structure and function.

Prenatal exposure to multiple pesticides is associated with auditory brainstem response at 9months in a cohort study of Chinese infants

BACKGROUND

Pesticides are associated with poorer neurodevelopmental outcomes, but little is known about the effects on sensory functioning.

METHODS

Auditory brainstem response (ABR) and pesticide data were available for 27 healthy, full-term 9-month-old infants participating in a larger study of early iron deficiency and neurodevelopment. Cord blood was analyzed by gas chromatography-mass spectrometry for levels of 20 common pesticides. The ABR forward-masking condition consisted of a click stimulus (masker) delivered via ear canal transducers followed by an identical stimulus delayed by 8, 16, or 64 milliseconds (ms). ABR peak latencies were evaluated as a function of masker-stimulus time interval. Shorter wave latencies reflect faster neural conduction, more mature auditory pathways, and greater degree of myelination. Linear regression models were used to evaluate associations between total number of pesticides detected and ABR outcomes. We considered an additive or synergistic effect of poor iron status by stratifying our analysis by newborn ferritin (based on median split).

RESULTS

Infants in the sample were highly exposed to pesticides; a mean of 4.1 pesticides were detected (range 0-9). ABR Wave V latency and central conduction time (CCT) were associated with the number of pesticides detected in cord blood for the 64ms and non-masker conditions. A similar pattern seen for CCT from the 8ms and 16ms conditions, although statistical significance was not reached. Increased pesticide exposure was associated with longer latency. The relation between number of pesticides detected in cord blood and CCT depended on the infant's cord blood ferritin level. Specifically, the relation was present in the lower cord blood ferritin group but not the higher cord blood ferritin group.

CONCLUSIONS

ABR processing was slower in infants with greater prenatal pesticide exposure, indicating impaired neuromaturation. Infants with lower cord blood ferritin appeared to be more sensitive to the effects of prenatal pesticide exposure on ABR latency delay, suggesting an additive or multiplicative effect.

The Anaphase-Promoting Complex (APC) ubiquitin ligase affects chemosensory behavior in C. elegans

The regulation of fundamental aspects of neurobiological function has been linked to the ubiquitin signaling system (USS), which regulates the degradation and activity of proteins and is catalyzed by E1, E2, and E3 enzymes. The Anaphase-Promoting Complex (APC) is a multi-subunit E3 ubiquitin ligase that controls diverse developmental and signaling processes in post-mitotic neurons; however, potential roles for the APC in sensory function have yet to be explored. In this study, we examined the effect of the APC ubiquitin ligase on chemosensation in Caenorhabditis elegans by testing chemotaxis to the volatile odorants, diacetyl, pyrazine, and isoamyl alcohol, to which wild-type worms are attracted. Animals with loss of function mutations in either of two alleles (g48 and ye143) of the gene encoding the APC subunit EMB-27 APC6 showed increased chemotaxis towards diacetyl and pyrazine, odorants sensed by AWA neurons, but exhibited normal chemotaxis to isoamyl alcohol, which is sensed by AWC neurons. The statistically significant increase in chemotaxis in the emb-27 APC6 mutants suggests that the APC inhibits AWA-mediated chemosensation in C. elegans. Increased chemotaxis to pyrazine was also seen with mutants lacking another essential APC subunit, MAT-2 APC1; however, mat-2 APC1 mutants exhibited wild type responses to diacetyl. The difference in responsiveness of these two APC subunit mutants may be due to differential strength of these hypomorphic alleles or may indicate the presence of functional sub-complexes of the APC at work in this process. These findings are the first evidence for APC-mediated regulation of chemosensation and lay the groundwork for further studies aimed at identifying the expression levels, function, and targets of the APC in specific sensory neurons. Because of the similarity between human and C. elegans nervous systems, the role of the APC in sensory neurons may also advance our understanding of human sensory function and disease.

Relationship between somatosensory deficit and brain somatosensory system after early brain lesion: A morphometric study

Cerebral Palsy (CP) is a group of permanent motor disorders due to non-progressive damage to the developing brain. Poor tactile discrimination is common in children with unilateral CP. Previous findings suggest the crucial role of structural integrity of the primary (S1) and secondary (S2) somatosensory areas located in the ipsilesional hemisphere for somatosensory function processing. However, no focus on the relationship between structural characteristics of ipsilesional S1 and S2 and tactile discrimination function in paretic hands has been proposed. Using structural MRI and a two-point discrimination assessment (2 PD), we explore this potential link in a group of 21 children (mean age 13 years and 7 months) with unilateral CP secondary to a periventricular white matter injury (PWMI) or middle cerebral artery infarct (MCA). For our whole sample there was a significant negative correlation between the 2 PD and the gray matter volume in the ipsilesional S2 (rho = -0.50 95% confidence interval [-0.76, -0.08], one-tailed p-value = 0.0109) and in the ipsilesional S1 (rho = -0.57, 95% confidence interval [-0.81, -0.19], one-tailed p-value = 0.0032). When studying these relationships with regard to the lesion types, we found these correlations were non-significant in the patients with PWMI but stronger in patients with MCA. According to our results, the degree of sensory impairment is related to the spared gray matter volume in ipsilesional S1 and S2 and is marked after an MCA stroke. Our work contributes to a better understanding of why some patients with CP have variable somatosensory deficit following an early brain lesion.

The effects of intensive bimanual training with and without tactile training on tactile function in children with unilateral spastic cerebral palsy: A pilot study

Children with unilateral spastic cerebral palsy (USCP) often have tactile impairments. Intensive bimanual training improves the motor abilities, but the effects on the sensory system have not been studied. Here we compare the effects of bimanual training with and without tactile training on tactile impairments. Twenty children with USCP (6-15.5 years; MACS: I-III) were randomized to receive either bimanual therapy (HABIT) or HABIT+tactile training (HABIT+T). All participants received 82 h of standardized HABIT. In addition 8 sessions of 1h were provided to both groups. The HABIT+T group received tactile training (without vision) using materials of varied shapes and textures. The HABIT group received training with the same materials without tactile directed training (full vision). Primary outcomes included grating orientation task/GOT and stereognosis. Secondary outcomes included two-point discrimination/TPD, Semmes-Weinstein monofilaments/SWM. The GOT improved in both groups after training, while stereognosis of the more-affected hand tended to improve (but p=0.063). No changes were found in the TPD and the SWM. There were no group×test interactions for any measure. We conclude tactile spatial resolution can improve after bimanual training. Either intensive bimanual training alone or incorporation of materials with a diversity of shapes/textures may drive these changes.

Sensory function: insights from Wave 2 of the National Social Life, Health, and Aging Project

OBJECTIVES

Sensory function, a critical component of quality of life, generally declines with age and influences health, physical activity, and social function. Sensory measures collected in Wave 2 of the National Social Life, Health, and Aging Project (NSHAP) survey focused on the personal impact of sensory function in the home environment and included: subjective assessment of vision, hearing, and touch, information on relevant home conditions and social sequelae as well as an improved objective assessment of odor detection.

METHOD

Summary data were generated for each sensory category, stratified by age (62-90 years of age) and gender, with a focus on function in the home setting and the social consequences of sensory decrements in each modality.

RESULTS

Among both men and women, older age was associated with self-reported impairment of vision, hearing, and pleasantness of light touch. Compared with women, men reported significantly worse hearing and found light touch less appealing. There were no gender differences for vision. Overall, hearing loss seemed to have a greater impact on social function than did visual impairment.

DISCUSSION

Sensory function declines across age groups, with notable gender differences for hearing and light touch. Further analysis of sensory measures from NSHAP Wave 2 may provide important information on how sensory declines are related to health, social function, quality of life, morbidity, and mortality in this nationally representative sample of older adults.

Leveraging biomedical informatics for assessing plasticity and repair in primate spinal cord injury

Recent preclinical advances highlight the therapeutic potential of treatments aimed at boosting regeneration and plasticity of spinal circuitry damaged by spinal cord injury (SCI). With several promising candidates being considered for translation into clinical trials, the SCI community has called for a non-human primate model as a crucial validation step to test efficacy and validity of these therapies prior to human testing. The present paper reviews the previous and ongoing efforts of the California Spinal Cord Consortium (CSCC), a multidisciplinary team of experts from 5 University of California medical and research centers, to develop this crucial translational SCI model. We focus on the growing volumes of high resolution data collected by the CSCC, and our efforts to develop a biomedical informatics framework aimed at leveraging multidimensional data to monitor plasticity and repair targeting recovery of hand and arm function. Although the main focus of many researchers is the restoration of voluntary motor control, we also describe our ongoing efforts to add assessments of sensory function, including pain, vital signs during surgery, and recovery of bladder and bowel function. By pooling our multidimensional data resources and building a unified database infrastructure for this clinically relevant translational model of SCI, we are now in a unique position to test promising therapeutic strategies' efficacy on the entire syndrome of SCI. We review analyses highlighting the intersection between motor, sensory, autonomic and pathological contributions to the overall restoration of function. This article is part of a Special Issue entitled SI: Spinal cord injury.

Sensory and motor peripheral nerve function and longitudinal changes in quadriceps strength

BACKGROUND

Poor peripheral nerve function is common in older adults and may be a risk factor for strength decline, although this has not been assessed longitudinally.

METHODS

We assessed whether sensorimotor peripheral nerve function predicts strength longitudinally in 1,830 participants (age = 76.3 ± 2.8, body mass index = 27.2 ± 4.6kg/m(2), strength = 96.3 ± 34.7 Nm, 51.0% female, 34.8% black) from the Health ABC study. Isokinetic quadriceps strength was measured semiannually over 6 years. Peroneal motor nerve conduction amplitude and velocity were recorded. Sensory nerve function was assessed with 10-g and 1.4-g monofilaments and average vibration detection threshold at the toe. Lower-extremity neuropathy symptoms were self-reported.

RESULTS

Worse vibration detection threshold predicted 2.4% lower strength in men and worse motor amplitude and two symptoms predicted 2.5% and 8.1% lower strength, respectively, in women. Initial 10-g monofilament insensitivity predicted 14.2% lower strength and faster strength decline in women and 6.6% lower strength in men (all p < .05).

CONCLUSION

Poor nerve function predicted lower strength and faster strength decline. Future work should examine interventions aimed at preventing declines in strength in older adults with impaired nerve function.

Neurotoxic evaluation of two organobromine model compounds and natural AOBr-containing surface water samples by a Caenorhabditis elegans test

Brominated organic compounds are known as disinfection byproducts. Very recently, however, even natural brominated organic compounds (analyzed as adsorbable organic bromine; AOBr) have been found in decaying freshwater cyanobacteria blooms. Among the identified compounds was dibromoacetic acid (DBAA), which has proven to be neurotoxic at rather high concentrations in mammalian assays. Currently it is open how single compounds as well as complex mixtures impact organisms at environmentally realistic concentrations. Furthermore, it is also unclear how natural organic matter, mainly humic substances (HS), which are present in all freshwater systems, modulates the toxic impact of AOBr. Therefore, two AOBr compounds (DBAA and tetrabromobisphenol-A; TBBP-A) and AOBr-containing water samples were tested using a Caenorhabditis elegans neurotoxicity assay that measured autonomic and sensory functions. TBBP-A had an impact on three response variables of C. elegans and can be classified neurotoxic. In contrast to our expectations, DBAA led to neurostimulation of two autonomic functions, but had a temporary impact on the defecation interval. All surface water samples contained measurable amounts of AOBr. Exposure of C. elegans to concentrated water samples - one in particular - increased three of the four locomotion traits and left defecation activity and both sensory variables unchanged. This stimulation might be due to unidentified compounds in the samples or to a hormetic effect of the AOBr compounds. Thermotactic behavior was characterized by a temporary preference for the colder environment, indicating a temporary mild neurotoxicity. Overall, the set of relative simple phenotypic tests used in the current study revealed a meaningful neurotoxic or neurostimulative profile in response to chemical compounds or natural samples. Furthermore, it shows that the resulting response to natural AOBr compounds at environmentally realistic concentrations was not necessarily adverse, but instead, that the mixtures of natural AOBr were neurostimulatory.

Urinary bladder, cystitis and nerve/urothelial interactions

A hallmark of functional pain syndromes, such as bladder pain syndrome/interstitial cystitis (BPS/IC) is pain in the absence of demonstrable infection or pathology of the viscera or associated nerves. There are no clear definitions of this syndrome, no proven etiologies and no effective treatments able to eradicate the symptoms. This condition is characterized by suprapubic pain, associated with bladder filling and can also be accompanied by a persistent strong desire to void, increased frequency of urination and nocturia. Severe cases of this disorder, which affects primarily women, can have considerable impact on the quality of life of patients due to extreme pain and urinary frequency, which are often difficult to treat. In addition, BPS/IC patients may also suffer co-morbid conditions where pain is a common symptom (such as irritable bowel syndrome, fibromyalgia). Theories explaining the pathology of bladder pain syndrome are many and include an altered bladder lining and possible contribution of a bacterial agent.

Peripheral nerve function and lower extremity muscle power in older men

OBJECTIVE

To assess whether sensorimotor peripheral nerve function is associated with muscle power in community-dwelling older men.

DESIGN

Longitudinal cohort study with 2.3±0.3 years of follow-up.

SETTING

One clinical site.

PARTICIPANTS

Participants (n=372; mean age ± SD, 77.2±5.1y; 99.5% white; body mass index, 27.9±3.7kg/m(2); power, 1.88±0.6W/kg) at 1 site of the Osteoporotic Fractures in Men Study (N=5994).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

A nerve function ancillary study was performed 4.6±0.4 years after baseline. Muscle power was measured using a power rig. Peroneal motor nerve conduction amplitude, distal motor latency, and mean f-wave latency were measured. Sensory nerve function was assessed using 10-g and 1.4-g monofilaments and sural sensory nerve conduction amplitude and distal latency. Peripheral neuropathy symptoms at the leg and feet were assessed by self-report.

RESULTS

After adjustments for age, height, and total body lean and fat mass, 1 SD lower motor (β=-.07, P<.05) and sensory amplitude (β=-.09, P<.05) and 1.4-g (β=-.11, P<.05) and 10-g monofilament insensitivity (β=-.17, P<.05) were associated with lower muscle power/kg. Compared with the effect of age on muscle power (β per year, -.05; P<.001), this was equivalent to aging 1.4 years for motor amplitude, 1.8 years for sensory amplitude, 2.2 years for 1.4-g monofilament detection, and 3.4 years for 10-g detection. Baseline 1.4-g monofilament detection predicted a greater decline in muscle power/kg. Short-term change in nerve function was not associated with concurrent short-term change in muscle power/kg.

CONCLUSIONS

Worse sensory and motor nerve function were associated with lower muscle power/kg and are likely important for impaired muscle function in older men. Monofilament sensitivity was associated with a greater decline in muscle power/kg, and screening may identify an early risk for muscle function decline in late life, which has implications for disability.