Functional electrical stimulation to enhance reactive balance among people with hemiparetic stroke

BACKGROUND

Individuals with stroke demonstrate a twofold higher fall incidence compared to healthy counterparts, potentially associated with deficits in reactive balance control, which is crucial for regaining balance from unpredictable perturbations to the body. Moreover, people with higher stroke-related motor impairment exhibit greater falls and cannot recover balance during higher perturbation intensities. Thus, they might need supplemental agents for fall prevention or even to be included in a perturbation-based protocol. Functional electrical stimulation is a widely used clinical modality for improving gait performance; however, it remains unknown whether it can enhance or interfere with reactive balance control.

METHODS

We recruited twelve ambulatory participants with hemiparetic stroke (61.48 ± 6.77 years) and moderate-to-high motor impairment (Chedoke-McMaster Stroke Leg Assessment ≤ 4/7). Each participant experienced 4 unpredicted paretic gait-slips, with and without functional electrical stimulation (provided 50-500 ms after perturbation) in random order. The paretic quadriceps muscle group was chosen to receive electrical stimulation, considering the role of support limb knee extensors for preventing limb-collapse. Outcomes including primary (laboratory falls), secondary (reactive stability, vertical limb support) and tertiary (compensatory step length, step initiation, execution time) measures were compared between the two conditions.

RESULTS

Participants demonstrated fewer falls, higher reactive stability, and higher vertical limb support (p < 0.05) following gait-slips with functional electrical stimulation compared to those without. This was accompanied by reduced step initiation time and a longer compensatory step (p < 0.05).

CONCLUSION

The application of functional electrical stimulation to paretic quadriceps following gait-slips reduced laboratory fall incidence with enhanced reactive balance outcomes among people with higher stroke-related motor impairment. Our results lay the preliminary groundwork for understanding the instantaneous neuromodulatory effect of functional electrical stimulation in preventing gait-slip falls, future studies could test its therapeutic effect on reactive balance. Clinical registry number: NCT04957355.

Age-related differences in reactive balance control and fall-risk in people with chronic stroke

BACKGROUND

Impaired reactive responses to sudden environmental perturbations contribute to heightened fall-risk in healthy aging and neurologically impaired populations. Previous studies have demonstrated individual contributions of paretic and non-paretic sides to fall-risk in people with stroke with variable levels of motor impairment. However, the combined effect of aging and unilateral cortical lesion on reactive balance control is not clearly understood. We therefore aimed to examine age-related differences in reactive balance control and fall-risk during laboratory-induced gait-slips in people with comparable stroke-related motor impairments.

METHODS

Thirteen younger (45.61 ± 4.61 years) and thirteen older (71.92 ± 6.50 years) adults with similar stroke-related impairment (on Fugl-Meyer Lower Extremity Assessment) were exposed to one overground gait-slip under each limb (paretic and non-paretic). Center of mass state stability and slipping kinematics (slip displacement and velocity) were computed. Clinical balance and mobility were also assessed.

RESULTS

On non-paretic slips, older adults with chronic stroke demonstrated greater falls and lower center of mass stability (its position and velocity) at post-slip touchdown compared to younger adults with chronic stroke (p < 0.01). This was accompanied with a greater peak slip displacement and faster peak slip velocity (p < 0.01). However, there were no such group differences noted on the paretic slips (p > 0.01).

CONCLUSION

Aging may have an independent, detrimental effect on reactive balance control in people with chronic stroke. Non-paretic deficits in controlling slip intensities (slip displacement and velocity) can accentuate fall-risk in older adults with chronic stroke. Further investigation is necessary to identify additional factors attributing to heightened fall-risk in older adults with chronic stroke.

Mobile Brain Imaging to Examine Task-Related Cortical Correlates of Reactive Balance: A Systematic Review

This systematic review examined available findings on spatial and temporal characteristics of cortical activity in response to unpredicted mechanical perturbations. Secondly, this review investigated associations between cortical activity and behavioral/biomechanical measures. Databases were searched from 1980-2021 and a total of 35 cross-sectional studies (31 EEG and 4 fNIRS) were included. Majority of EEG studies assessed perturbation-evoked potentials (PEPs), whereas other studies assessed changes in cortical frequencies. Further, fNIRS studies assessed hemodynamic changes. The PEP-N1, commonly identified at sensorimotor areas, was most examined and was influenced by context prediction, perturbation magnitude, motor adaptation and age. Other PEPs were identified at frontal, parietal and sensorimotor areas and were influenced by task position. Further, changes in cortical frequencies were observed at prefrontal, sensorimotor and parietal areas and were influenced by task difficulty. Lastly, hemodynamic changes were observed at prefrontal and frontal areas and were influenced by task prediction. Limited studies reported associations between cortical and behavioral outcomes. This review provided evidence regarding the involvement of cerebral cortex for sensory processing of unpredicted perturbations, error-detection of expected versus actual postural state, and planning and execution of compensatory stepping responses. There is still limited evidence examining cortical activity during reactive balance tasks in populations with high fall-risk.

Treatment of Urethral Intercourse and Impact on Female Sexual Function

Background

Urethral intercourse is a very rare entity which usually presents as urinary incontinence during and after intercourse and is most commonly seen in patients with vaginal agenesis (Mayer–Rokitansky–Hauser Syndrome) or hypoplasia, or other rear vaginal anomalies.

Aim

To evaluate management and outcomes for vaginal and urethral consequences of urethral intercourse, including urinary incontinence.

Methods

Between February 2006 and March 2021, 8 women aged from 17 to 22 years underwent genital and urethral reconstruction due to consequences of urethral sexual intercourse. Vaginal reconstruction included sigmoid vaginoplasty and introitoplasty with division of the vaginal septum in cases of vaginal agenesis (5 cases) and vaginal duplication (3 cases), respectively. Incontinence was treated by sling procedures in 5 women with longer history of urethral coitus and evident bladder neck prolapse.

Outcomes

Sexual and psychosexual outcomes assessment was based on the Female Sexual Function Index and standardized questionnaires.

Results

Follow-up ranged from 9 to 188 months (mean 78 months). Good esthetical and functional results were achieved in all 8 women. All patients reported satisfactory sexual intercourse. All 5 incontinent women who had underwent sling procedure were continent. In one of 3 nontreated cases, additional sling treatment was indicated 6 months after vaginal reconstruction with satisfactory outcome. One patient with vaginal duplication reported a successful pregnancy with a Caesarean section delivery.

Clinical Implications

Urinary incontinence with megalourethra in young women, along with the presence of Mullerian anomalies should raise suspicion of urethral coitus. Surgical treatment includes correction of vaginal anomalies and management of consequences.

Strengths and Limitations

This study represents one of the largest series for urethral intercourse, with assessment of psychosexual outcome. The limitation is the lack of statistical analysis due to small sample size.

Conclusion

Urethral intercourse is very rare, but it can cause severe consequences. It is important to recognize this occurrence and treat it by well-known vaginal or urethral reconstructive procedures.

Djordjevic ML, Bizic M, Stojanovic B, et al. Treatment of Urethral Intercourse and Impact on Female Sexual Function. Sex Med 2022;10:100534.

Assessing Skin Blood Flow and Interface Pressure in Patients With Spinal Cord Injury Provided an Alternating Pressure Overlay: A Cross-sectional Study

The effects of an alternating pressure (AP) overlay on the skin are not fully understood.

PURPOSE

This study was conducted among persons with spinal cord injury (SCI) to examine skin blood flow (SBF) and interface pressure (IP) during and after AP overlay use.

METHODS

In this cross-sectional, repeated measures study, persons eligible for participation were clinic outpatients from a large metropolitan area in the midwest United States who were 18 to 65 years old with a SCI with a neurologic level of injury at T10 or above for more than 1 year and used a wheelchair for primary mobility. Persons with a current pressure injury, diabetes mellitus, and/or hypertension or other vascular or pulmonary diseases were excluded. Data regarding age, gender, body mass index (BMI), duration of SCI, and American Spinal Injury Association Impairment Scale scores were collected. The experimental study involved 3 protocols: the AP protocol (participants lay supine for 40 minutes on an operating room [OR] pad with a low-profile AP that used a 10-minute inflation-deflation cycle); the post-AP protocol (participants lay on the 2-inch foam OR pad for 40 minutes), with 30 minutes of rest in between; and the control protocol, comprised of 40-minutes of laying supine on the OR pad. Each participant served as his/her own control. Outcome variables included 1) peak IP (the highest value among adjoining sensors located at the highest pressure point); 2) averaged IP (the averaged value of the sensors), calculated from pressure mapping system data from the sacrum and left heel; and SBF, measured using a laser Doppler flowmetry system. Descriptive analyses were performed for all variables to determine need for parametric or nonparametric analyses. The mean value of peak IP, averaged IP among inflation and deflation cycles of AP, and post-AP and control protocols were compared using repeated measures analysis of variance (ANOVA). Mean SBF among inflation and deflation cycles of AP and post-AP and control protocols were compared using the nonparametric Friedman test, and Wilcoxon signed rank tests were used to compare the SBF responses during the post-loading period. If the results of repeated measures ANOVA or Friedman tests were statistically significant, paired t tests and Wilcoxon signed rank tests were used for pairwise comparison with Bonferroni correction at alpha level 0.0125, respectively.

RESULTS

Among the 15 participants (11 men, 4 women; age 41.77 ± 14.49 [range 20-62] years; BMI 26.81 ± 4.13 [range 22-37]; injury duration 17 ± 14.62 [range 1-48] years; mostly (11) African American), peak IP decreased during the AP deflation at sacrum (51.47 ± 30.18 mm Hg vs. 114.13 ± 60.97 mm Hg; P = .002) and heel (26.79 ± 12.91 mm Hg vs. 53.05 ± 18.22 mm Hg; P = 0 .001), and SBF increased at the heel (27.92 ± 32.15 vs. 10.43 ± 11.16 au; P = .006) but was not significant at the sacrum (15.54 ± 15.33 au vs. 11.96 ± 10.26 au, P = .023). Peak IP decreased during post-AP at the sacrum (104.62 ± 58.17 mm Hg; P = .002) but not at the heel (47.69 ± 16.21 mm Hg; P = .097). SBF increased during post-AP at the sacrum (15.78 ± 15.82 au; P = .012) but not at the heel (16.31 ± 29.18 au, P = .427).

CONCLUSION

An AP overlay redistributed IP and increased SBF at the sacrum and heel during use, and its effect 40 minutes after removal was observed only at the sacrum. Studies, including evaluating the lasting effect of AP on weight-bearing tissue protection at different anatomical locations, are needed.

Nanoscale petrographic and geochemical insights on the origin of the Palaeoproterozoic stromatolitic phosphorites from Aravalli Supergroup, India

Stromatolites composed of apatite occur in post-Lomagundi-Jatuli successions (late Palaeoproterozoic) and suggest the emergence of novel types of biomineralization at that time. The microscopic and nanoscopic petrology of organic matter in stromatolitic phosphorites might provide insights into the suite of diagenetic processes that formed these types of stromatolites. Correlated geochemical micro-analyses of the organic matter could also yield molecular, elemental and isotopic compositions and thus insights into the role of specific micro-organisms among these communities. Here, we report on the occurrence of nanoscopic disseminated organic matter in the Palaeoproterozoic stromatolitic phosphorite from the Aravalli Supergroup of north-west India. Organic petrography by micro-Raman and Transmission Electron Microscopy demonstrates syngeneity of the organic matter. Total organic carbon contents of these stromatolitic phosphorite columns are between 0.05 and 3.0 wt% and have a large range of δ(13) Corg values with an average of -18.5‰ (1σ = 4.5‰). δ(15) N values of decarbonated rock powders are between -1.2 and +2.7‰. These isotopic compositions point to the important role of biological N2 -fixation and CO2 -fixation by the pentose phosphate pathway consistent with a population of cyanobacteria. Microscopic spheroidal grains of apatite (MSGA) occur in association with calcite microspar in microbial mats from stromatolite columns and with chert in the core of diagenetic apatite rosettes. Organic matter extracted from the stromatolitic phosphorites contains a range of molecular functional group (e.g. carboxylic acid, alcohol, and aliphatic hydrocarbons) as well as nitrile and nitro groups as determined from C- and N-XANES spectra. The presence of organic nitrogen was independently confirmed by a CN(-) peak detected by ToF-SIMS. Nanoscale petrography and geochemistry allow for a refinement of the formation model for the accretion and phototrophic growth of stromatolites. The original microbial biomass is inferred to have been dominated by cyanobacteria, which might be an important contributor of organic matter in shallow-marine phosphorites.

Palaeosol control on groundwater flow and pollutant distribution: the example of arsenic

The consumption of groundwater polluted by arsenic (As) has a severe and adverse effect on human health, particularly where, as happens in parts of SE Asia, groundwater is supplied largely from fluvial/deltaic aquifers. The lateral distribution of the As-pollution in such aquifers is heterogeneous. The cause of the heterogeneity is obscure. The location and severity of the As-pollution is therefore difficult to predict, despite the importance of such predictions to the protection of consumer health, aquifer remediation, and aquifer development. To explain the heterogeneity, we mapped As-pollution in groundwater using 659 wells across 102 km(2) of West Bengal, and logged 43 boreholes, to reveal that the distribution of As-pollution is governed by subsurface sedimentology. Across 47 km(2) of contiguous palaeo-interfluve, we found that the shallow aquifer (<70 mbgl) is unpolluted by As (<10 μg/L) because it is capped by an impermeable palaeosol of red clay (the last glacial maximum palaeosol, or LGMP, of ref 1 ) at depths between 16 and 24 mbgl. The LGMP protects the aquifer from vertical recharge that might carry As-rich water or dissolved organic matter that might drive reduction of sedimentary iron oxides and so release As to groundwater. In 55 km(2) of flanking palaeo-channels, the palaeosol is absent, so invasion of the aquifer by As and dissolved organic matter can occur, so palaeo-channel groundwater is mostly polluted by As (>50 μg/L). The role of palaeosols and, in particular, the LGMP, has been overlooked as a control on groundwater flow and pollutant movement in deltaic and coastal aquifers worldwide. Models of pollutant infiltration in such environments must include the appreciation that, where the LGMP (or other palaeosols) are present, recharge moves downward in palaeo-channel regions that are separated by palaeo-interfluvial regions where vertical recharge to underlying aquifers cannot occur and where horizontal flow occurs above the LGMP and any aquifer it caps.

A novel computational and structural analysis of nsSNPs in CFTR gene

Single Nucleotide Polymorphisms (SNPs) are being intensively studied to understand the biological basis of complex traits and diseases. The Genetics of human phenotype variation could be understood by knowing the functions of SNPs. In this study using computational methods, we analyzed the genetic variations that can alter the expression and function of the CFTR gene responsible candidate for causing cystic fibrosis. We applied an evolutionary perspective to screen the SNPs using a sequence homology-based SIFT tool, which suggested that 17 nsSNPs (44%) were found to be deleterious. The structure-based approach PolyPhen server suggested that 26 nsSNPS (66%) may disrupt protein function and structure. The PupaSuite tool predicted the phenotypic effect of SNPs on the structure and function of the affected protein. Structure analysis was carried out with the major mutation that occurred in the native protein coded by CFTR gene, and which is at amino acid position F508C for nsSNP with id (rs1800093). The amino acid residues in the native and mutant modeled protein were further analyzed for solvent accessibility, secondary structure and stabilizing residues to check the stability of the proteins. The SNPs were further subjected to iHAP analysis to identify htSNPs, and we report potential candidates for future studies on CFTR mutations.

Cure of undifferentiated small cell carcinoma of the urinary bladder with M-VAC chemotherapy

Small cell carcinoma (SCC) of the urinary bladder is a rare, aggressive malignancy with approximately 135 cases reported in the literature. Treatments have included chemotherapy, radical surgery, radiotherapy, and combinations of these. We present the apparent cure of a 73-year-old man who presented with clinical stage T2 SCC of the urinary bladder. He was treated with three cycles of methotrexate, vinblastine, Adriamycin (doxorubicin), and cisplatin (M-VAC) chemotherapy. Subsequent radical cystoprostatectomy revealed no pathologic evidence of tumor. The patient is alive and well with no evidence of recurrence 3 years post cystectomy. A brief review of the literature is also presented.

Coccygeal muscle injury in English Pointers (limber tail)

A condition colloquially referred to as "limber tail" and "cold tail" is familiar to people working with hunting dogs, primarily Pointers and Labrador Retrievers. The typical case consists of an adult dog that suddenly develops a flaccid tail. The tail either hangs down from the tail base or is held out horizontally for several inches from the tail base and then hangs straight down or at some degree below horizontal. Initially, the hair on the dorsal aspect of the proximal tail may be raised and dogs may resent palpation of the area 3-4 inches (8-10 cm) from the tail base. Most dogs recover spontaneously within a few days to weeks. Anecdotal reports suggest that anti-inflammatory drugs administered within 24 hours after onset hasten recovery. Less than one half of affected dogs experience a recurrence. Affected Pointers almost always have a history of prolonged cage transport, a hard workout the previous day, or exposure to cold or wet weather Most owners and trainers familiar with the condition do not seek veterinary assistance. In cases where people are not familiar with this disease, other conditions such as a fracture, spinal cord disease, impacted anal glands, or prostatic disease have been incorrectly diagnosed. We examined 4 affected Pointers and found evidence of coccygeal muscle damage, which included mild elevation of creatine kinase early after onset of clinical signs, needle electromyographic examination showing abnormal spontaneous discharges restricted to the coccygeal muscles several days after onset, and histopathologic evidence of muscle fiber damage. Specific muscle groups, namely the laterally positioned intertransversarius ventralis caudalis muscles, were affected most severely. Abnormal findings on thermography and scintigraphy further supported the diagnosis.

Characterization of a recent retroposon insertion on mouse chromosome 2 and localization of the cognate parental gene to chromosome 11

The genomic sequence on mouse Chromosome (Chr) 2 corresponding to a previously identified novel cDNA has been characterized. The genomic organization of this locus, adjacent to the beta 2 microglobulin gene, has the properties of a processed gene or retroposon including the presence of a short flanking direct repeat, a polyadenylation signal/poly A tract, and the absence of introns. Analysis of inbred and wild-derived Mus DNAs reveals the retroposon to be a feature only of M. m. domesticus subspecies, suggesting that the insertion event is relatively recent. This notion is supported by the presence of an open reading frame and the lack of sequence divergence in the flanking direct repeats. The complex chromatin configuration characteristic of this region in mouse and human is not, therefore, related to this cDNA. The cognate parental gene encoding the cDNA was mapped to Chr 11. A further, more ancient retroposon present in many Mus species localizes to Chr 17.

Platelet function testing in the pony

Platelet isolation techniques and platelet function were evaluated in 35 adult ponies. Platelet recovery from whole blood was consistent and the preparation of platelet rich plasma was facilitated by an enhanced erythrocyte sedimentation rate. All platelet samples aggregated in response to 10 microM ADP. However, concentrations of ADP as high as 100 microM did not elicit significant 14C-serotonin release. Collagen induced irreversible platelet aggregation and 14C-serotonin release in all samples. The threshold dose for collagen in most ponies was 1.5 micrograms. Arachidonic acid (500 microM) failed to induce irreversible platelet aggregation or 14C-serotonin release in any of the samples evaluated. Pony platelets were nonresponsive to epinephrine (5.5 microM).

Carcinoma of the urinary bladder in Zambia. A quantitative estimation of Schistosoma haematobium infection

The incidence and intensity of schistosomal infection in 50 African malignant bladders determined by quantitative analysis have been compared with a matched control group of nonmalignant cadaver bladders, and the incidence of radiological calcification in the former has been compared with that of 50 adult urinary bilharziasis patients without associated malignancy. Compared with 45% in the non-malignant group, schistosomal infection was present in an overwhelming 94% of the malignant cases. Radiological calcification in the malignant bladders (38%) was slightly more than in patients with urinary bilharziasis (35%). In the majority of the malignant bladders (55.3%) the parasitic infection was noted to be of moderate to low intensity. It has been suggested that the overall severity of schistosomal infection is unlikely to be the sole factor in the pathogenesis of carcinoma of the urinary bladder.

The pharmacokinetics and pharmacodynamics of the diuretic bumetanide in hepatic and renal disease

1 Bumetanide (1 mg) was given orally and intravenously to a group of patients with chronic renal failure (n = 6) and to another group with cirrhosis of the liver (n = 8). 2 The pharmacokinetics, using a two-compartment model, and the pharmacodynamics of the drug in these patients were compared with those previously obtained for normal subjects. 3 In the renal group serum bumetanide concentrations were higher than for the normal subjects and the terminal half-lives were significantly prolonged (P less than 0.001). A decreased whole body clearance was attributable to a low renal clearance of drug, the non-renal clearance being significantly increased (P less than 0.01). 4 For the patients with liver disease, serum bumetanide concentrations were higher than for the renal group, and the terminal half-lives were significantly further prolonged (P less than 0.001). Both non-renal and renal clearances were significantly reduced (P less than 0.001). 5 Absorption rates were not significantly altered in either group and the values of F (bioavailability) were 0.82 and 0.95 for the patients with renal disease and hepatic disease, respectively. 6 A poor pharmacodynamic response and a reduced bumetanide excretion rate were observed for the patients with chronic renal failure, whereas with hepatic disease normal bumetanide excretion rates were observed with an impaired diuretic response.

The pharmacokinetics and pharmacodynamics of bumetanide in normal subjects

The pharmacokinetics and pharmacodynamics of bumetanide (1 mg) administered either orally or intravenously were studied in a group of normal subjects using high-pressure liquid chromatography. A two-compartment model adequately fitted the intravenous data. Renal clearance (85 ml min-1) contributed 65% to the total elimination of bumetanide irrespective of whether a model-dependent or model-independent method was used. Oral administration of bumetanide elicited a greater and a more prolonged pharmacological response than did intravenous bumetanide. An attempt is made to relate the pharmacokinetics of the drug to its pharmacodynamics.