Precision Balance Assessment in Parkinson's Disease: Utilizing Vision-Based 3D Pose Tracking for Pull Test Analysis.

Postural instability is a common complication in advanced Parkinson's disease (PD) associated with recurrent falls and fall-related injuries. The test of retropulsion, consisting of a rapid balance perturbation by a pull in the backward direction, is regarded as the gold standard for evaluating postural instability in PD and is a key component of the neurological examination and clinical rating in PD (e.g., MDS-UPDRS). However, significant variability in test execution and interpretation contributes to a low intra- and inter-rater test reliability. Here, we explore the potential for objective, vision-based assessment of the pull test (vPull) using 3D pose tracking applied to single-sensor RGB-Depth recordings of clinical assessments. The initial results in a cohort of healthy individuals (n = 15) demonstrate overall excellent agreement of vPull-derived metrics with the gold standard marker-based motion capture. Subsequently, in a cohort of PD patients and controls (n = 15 each), we assessed the inter-rater reliability of vPull and analyzed PD-related impairments in postural response (including pull-to-step latency, number of steps, retropulsion angle). These quantitative metrics effectively distinguish healthy performance from and within varying degrees of postural impairment in PD. vPull shows promise for straightforward clinical implementation with the potential to enhance the sensitivity and specificity of postural instability assessment and fall risk prediction in PD.

Short anagen syndrome: A case series and algorithm for diagnosis.

BACKGROUND: The short anagen syndrome (SAS) is a rare idiopathic pediatric disorder characterized by the short duration of the anagen phase. SAS mainly affects Caucasian children. Parents complain of their child's inability to grow long hair. Topical minoxidil may be an effective treatment for SAS; however, a slow spontaneous improvement is typical. OBJECTIVE: Our aim was to collect data on out cases of SAS and create an algorithm to facilitate diagnosis of SAS. METHODS: A retrospective review of 25 patients with SAS was performed within the Dermatology Department of the University of Bologna. We collected data regarding symptoms, pull test, hair card test, trichoscopy, trichogram, treatments, including biotin and minoxidil, and clinical outcome. RESULTS: Characteristic findings included parental reporting that the hair had not required a haircut, hair card test showing hairs with conical-shaped tips, and hair shafts of different diameters, with more 10%-20% of hair shafts less than 60 µm thick on trichoscopy. Trichogram revealed an increased percentage of telogen hair with normal hair shafts and tapering ends. The mean anagen-to-telogen ratio was 66:34 (normal ratio 90:10). CONCLUSION: We developed an algorithm to facilitate the diagnosis of this rare hair disease using clinical examination and invasive and non-invasive testing to differentiate SAS from other forms of pediatric alopecia. In conclusion, the collected data of the therapy showed that biotin alone or in combination with topical minoxidil is an effective treatment for SAS.

Contrasting subsurface denitrification characteristics under temperate pasture lands and its implications for nutrient management in agricultural catchments.

Subsurface denitrification plays a key role in the reduction or 'attenuation' of nitrate contamination of groundwater and surface waters. We investigated subsurface denitrification characteristics in the vadose zone and shallow groundwater at four sites under pastoral farming in the Manawatu River catchment, located in the lower part of North Island, New Zealand. The denitrification potential of the vadose zone was determined by the laboratory incubation assays measuring the denitrifying enzyme activity (DEA) in soil samples collected from different soil horizons (up to 2.1 m below ground surface), whereas denitrification rates in shallow groundwaters were measured in situ by single-well, push-pull tests conducted in piezometers installed at multiple depths at the study sites. Soils and underlying geology, defining hydrogeologic settings, appear to influence the spatial variability of subsurface denitrification characteristics at the study sites. Where the vadose zone is thin and composed of coarse-textured soils, percolation of nitrate was evident in observed high nitrate-nitrogen concentrations (>5 mg L-1) in oxic and young shallow groundwaters, but low nitrate-nitrogen concentrations (<0.05 mg L-1) were observed in the reduced shallow groundwater found underneath the fine textured soils and/or a thick vadose zone. This was confirmed by the push-pull tests measuring denitrification rates from 0.08 to 1.07 mg N L-1 h-1 in the reduced shallow groundwaters (dissolved oxygen or DO < 0.5 mg L-1), while negligible in the oxic groundwaters (DO > 5 mg L-1) found at the study sites. These contrasting subsurface denitrification characteristics determine the ultimate delivery of nitrate losses from agricultural soils to receiving waters, where the fine textured thick vadose zone and reducing groundwater conditions offer nitrate reduction in the subsurface environment.

Neurophysiological analysis of the clinical pull test.

Postural reflexes are impaired in conditions such as Parkinson's disease, leading to difficulty walking and falls. In clinical practice, postural responses are assessed using the "pull test," where an examiner tugs the prewarned standing patient backward at the shoulders and grades the response. However, validity of the pull test is debated, with issues including scaling and variability in administration and interpretation. It is unclear whether to assess the first trial or only subsequent repeated trials. The ecological relevance of a forewarned backward challenge is also debated. We therefore developed an instrumented version of the pull test to characterize responses and clarify how the test should be performed and interpreted. In 33 healthy participants, "pulls" were manually administered and pull force measured. Trunk and step responses were assessed with motion tracking. We probed for the StartReact phenomenon (where preprepared responses are released early by a startling stimulus) by delivering concurrent normal or "startling" auditory stimuli. We found that the first pull triggers a different response, including a larger step size suggesting more destabilization. This is consistent with "first trial effects," reported by platform translation studies, where movement execution appears confounded by startle reflex-like activity. Thus, first pull test trials have clinical relevance and should not be discarded as practice. Supportive of ecological relevance, responses to repeated pulls exhibited StartReact, as previously reported with a variety of other postural challenges, including those delivered with unexpected timing and direction. Examiner pull force significantly affected the postural response, particularly the size of stepping. NEW & NOTEWORTHY We characterized postural responses elicited by the clinical "pull test" using instrumentation. The first pull triggers a different response, including a larger step size suggesting more destabilization. Thus, first trials likely have important clinical and ecological relevance and should not be discarded as practice. Responses to repeated pulls can be accelerated with a startling stimulus, as reported with a variety of other challenges. Examiner pull force was a significant factor influencing the postural response.

Hair pull test: Evidence-based update and revision of guidelines.

BACKGROUND: The hair pull test lacks validation and has unclear pretest guidelines. OBJECTIVE: We sought to quantify normal hair pull test values and elucidate the effect of pretest hair washing and brushing. The impact of hair texture and lifestyle was also examined. METHODS: Participants (n = 181) completed a questionnaire recording demographics, medications, and hair health/history. A single hair pull test (scalp vertex) was performed. RESULTS: The mean number of hairs removed per pull was 0.44 (SD 0.75). There was no significant difference in the mean number of hairs removed regardless of when participants washed (P = .20) or brushed (P = .25) their hair. Hair pull test values were similar between Caucasian-, Asian-, and Afro-textured hair. There was no significant difference in hair pull values between participants taking medications affecting hair loss and participants not taking these medications (P = .33). Tight hairstyles did not influence hair pull test values. LIMITATIONS: Participant hair washing and brushing could not be controlled during the study, but this information was documented and analyzed. CONCLUSION: Normal values for the hair pull test should be reduced to 2 hairs or fewer (97.2% of participants). The current 5-day restriction on pretest hair washing can be reduced and brushing be made permissible.

Maintaining balance against force perturbations: impaired mechanisms unresponsive to levodopa in Parkinson's disease.

There is evidence that postural instability associated with Parkinson's disease (PD) is not adequately improved by levodopa, implying involvement of nondopaminergic pathways. However, the mechanisms contributing to postural instability have yet to be fully identified and tested for their levodopa responsiveness. In this report we investigate balance processes that resist external forces to the body when standing. These include in-place responses and the transition to protective stepping. Forward and backward shoulder pulls were delivered using two force-feedback-controlled motors and were randomized for direction, magnitude, and onset. Sixteen patients with PD were tested OFF and ON levodopa, and 16 healthy controls were tested twice. Response behavior was quantified from 3-dimensional ground reaction forces and kinematic measurements of body segments and total body center-of-mass (CoM) motion. In-place responses resisting the pull were significantly smaller in PD as reflected in reduced horizontal anteroposterior ground reaction force and increased CoM displacement. Ankle, knee, and hip moments contributing to this resistance were smaller in PD, with the knee extensor moment to backward pulls being the most affected. The threshold force needed to evoke a step was also smaller for PD in the forward direction. Protective steps evoked by suprathreshold pulls showed deficits in PD in the backward direction, with steps being shorter and more steps being required to arrest the body. Levodopa administration had no significant effect on either in-place or protective stepping deficits. We conclude that processes employed to maintain balance in the face of external forces show impairment in PD consistent with disruption to nondopaminergic systems.

Extraction of the pull force from inertial sensors during the pull test for Parkinson's disease: A reliability study.

OBJECTIVE: To examine the inter- and intra-rater reliability of the pull test in patients with Parkinson's disease (PD) using the extracted pull force. METHODS: In this inter- and intra-rater reliability study, two raters performed a pull test on 30 patients with PD. The pull force was quantified using inertial sensors attached to the rater's right hand and the patient's lower trunk. In this study, the pull force was calculated as an extracted three-dimensional vector quantity, the resultant acceleration, and was expressed in m/s2. Inter- and intra-rater reliabilities were analyzed using the interclass correlation coefficient (ICC) for the pull force and Cohen's weighted kappa (κw) for the pull test score. Furthermore, Bland-Altman analysis was used to investigate systematic errors. RESULTS: The inter- and intra-rater reliability of the pull force was very poor (ICC = 0.033-0.214). Bland-Altman analysis revealed no systematic errors in the pull forces between the two test points. Conversely, κw for the pull test scores ranged from 0.763 to 0.920, indicating substantial to almost perfect agreement. CONCLUSION: The pull test score was reliable despite variations in the quantified pull force for inter- and intra-rater reliability. Our findings suggest that the pull test is a robust tool for evaluating postural instability in patients with PD and that the pull force probably does not affect scoring performance.

The Electromagnetic Noise Level Influence on the Laser Micro-Perforation Process Specific to Automotive Components.

This article focuses on the influence of generated electromagnetic noise (energy) during the micro-perforation process. This study aims to investigate the critical parameters and effects of using laser technology in the processing of textile materials for airbags. Different levels of electromagnetic noise and material thicknesses were investigated to ensure the quality of manufactured parts and the best component performance. A factorial analysis (DOE) was developed to evaluate the influence of electromagnetic noise levels over pull test results and its effect on the micro-perforation process. The overall inferential analysis concludes a significant influence of the noise levels on micro-perforation processing. The detailed analysis suggests that 1.2 V is an optimal level of electromagnetic noise where the material maintains its mechanical properties in a more predictable and consistent manner. Additionally, the factorial design provides significant evidence for an interaction and main effects' influences of analyzed factors. The obtained results in this study have demonstrated that monitoring and controlling the noise level have beneficial effects over the laser processing. This ensures that the safety aspect of the produced parts is entirely upheld and protected. Also, this research contributes to improving the manufacturing process and ensures that high-quality products are obtained, being suitable for use in sensitive applications such as automotive airbags.

Objective quantification of responses to the clinical pull-test in people with Parkinson's disease.

BACKGROUND: Postural instability can occur in the later-stages of Parkinson's disease (PD). The clinical pull-test is scored on a 0-4 scale on the Unified Parkinson's disease rating scale (UPDRS), with postural instability scored 2 or higher. This ordinal scale does not adequately track progression in early-PD or predict development of postural instability. RESEARCH QUESTION: To develop a test that quantifiably measured the backward stepping response on the pull-test in early-PD. METHODS: Participants (35 controls and 79 PD participants) were prospectively enrolled in this study. Participants stepped backwards with each shoulder pull at four strengths on an instrumented gait mat. Four spatiotemporal parameters (reaction-time, step-back-time, step-back-distance, step-back-velocity) were quantified using Protokinetics Movement Analysis Software. Spatiotemporal pull-test parameters were compared to standard PD measures using linear regression and correlation coefficients. Repeated measures analysis was used to determine group differences in pull-test parameters. In a subset of participants repeated testing was performed and Bland-Altman plots were used to determine reproducibility of the pull-test parameters. RESULT: Step-back-distance and step-back-velocity were inversely related to motor UPDRS and freezing of gait questionnaire scores. PD participants had shorter step-back-distance than controls adjusted for age and sex. Repeat assessments in 16 participants, on average 0.7 years apart, showed good agreement on most of the quantified parameters. SIGNIFICANCE: The backward stepping response in PD participants was quantifiable, reproducible, and related to disease severity and could be used to quantify progression towards postural instability in early-PD.

Polyacrylic Acid Hydrogel Coating for Underwater Adhesion: Preparation and Characterization.

Underwater adhesion involves bonding substrates in aqueous environments or wet surfaces, with applications in wound dressing, underwater repairs, and underwater soft robotics. In this study, we investigate the underwater adhesion properties of a polyacrylic acid hydrogel coated substrate. The underwater adhesion is facilitated through hydrogen bonds formed at the interface. Our experimental results, obtained through probe-pull tests, demonstrate that the underwater adhesion is rapid and remains unaffected by contact pressure and pH levels ranging from 2.5 to 7.0. However, it shows a slight increase with a larger adhesion area. Additionally, we simulate the debonding process and observe that the high-stress region originates from the outermost bonding region and propagates towards the center, spanning the thickness of the target substrate. Furthermore, we showcase the potential of using the underwater adhesive hydrogel coating to achieve in-situ underwater bonding between a flexible electronic demonstration device and a hydrogel contact lens. This work highlights the advantages of employing hydrogel coatings in underwater adhesion applications and serves as inspiration for the advancement of underwater adhesive hydrogel coatings capable of interacting with a wide range of substrates through diverse chemical and physical interactions at the interface.

Postural instability in Parkinson's disease assessed with clinical "pull test" and standardized postural perturbations: effect of medication and body weight support.

OBJECTIVE: This experiment tested if balance performance differed between a standardized treadmill surface perturbation task and a clinical pull test and was affected by medication or the presence of body weight support in people with Parkinson's disease (PD). METHODS: Twenty-seven individuals were tested (14 PD in both ON- and OFF-medication states). Clinical pull test and rapid forward (backward fall) translations of the support surface were applied to induce postural reactions requiring at least 1 step to restore balance. The effects of pull type (clinical vs. treadmill), partial bodyweight support (0 vs 20% body weight) and group (control, PD ON-meds and PD OFF-meds) on reactive stepping as well as practice/learning effect were examined. The number of steps taken and the first step duration were entered in linear repeated-measures mixed-effect models separately. RESULTS: The effects of pull type, group, and bodyweight support were all significant in both metrics, as was ON- vs. OFF-medication. A significant interaction term (group x pull type) was found in the first step duration, showing that the group difference was greater in treadmill compared to the clinical pull test. A significant practice effect was also observed within and across testing sessions. CONCLUSIONS: A standardized treadmill perturbation performed slightly better than the classical pull test in distinguishing between groups, and partial weight support did not substantially degrade the test's performance to detect the balance deficits in people with PD.

A modified and rapid method for the single-well push-pull (SWPP) test using SF6, Kr, and uranine tracers.

In the present study, a single-well push-pull (SWPP) test was conducted with multi-component tracers, including inert gas (SF6 and Kr) and uranine (conservative), to understand the volatile/semi-volatile component transport characteristics in the groundwater system. In an SWPP test, it is essential to obtain an initial breakthrough curve (BTC) of the inert gas concentration at the beginning of the pulling stage to analyze the hydraulic properties of the groundwater system. As a result of the SWPP test using a proposed method in this study, physicochemical parameters of the groundwater and BTC of gas tracers and uranine were acquired simultaneously and successfully. In addition, on-site measurements of uranine, pCO2, and water quality data, such as electrical conductivity (EC), temperature, pH, and dissolved oxygen, were undertaken. Modification of an existing pCO2 measuring system allowed the gas samples to be collected, transported, and analyzed for inert gas components within a few hours. As a result, reliable and interpretable data with a recovery ratio of 26%, 85%, and 95% for SF6, Kr, and uranine, respectively, were obtained. The differences in the recovery ratio were utilized to identify the environmental system, whether it contains gas inside the isolated system (closed) or not (open), and to understand plume behavior characteristics in the experimental zone. By applying a two-dimensional advection-dispersion model to the acquired tracer test data and comparing the observed and computed tracer concentrations, helpful information was obtained on the hydraulic and transport characteristics of the targeted zone. This method can be extended to the design of dissolved CO2 transport monitoring of an aquifer above a CCS site.

Foraging on anthropogenic food predicts problem-solving skills in a seabird.

Species and populations with greater cognitive performance are more successful at adapting to changing habitats. Accordingly, urban species and populations often outperform their rural counterparts on problem-solving tests. Paradoxically, urban foraging also might be detrimental to the development and integrity of animals' brains because anthropogenic foods often lack essential nutrients such as the long-chain omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are important for cognitive performance in mammals and possibly birds. We tested whether urbanization or consumption of EPA and DHA are associated with problem-solving abilities in ring-billed gulls, a seabird that historically exploited marine environments rich in omega-3 fatty acids but now also thrives in urban centres. Using incubating adults nesting across a range of rural to urban colonies with equal access to the ocean, we tested whether urban gulls preferentially consumed anthropogenic food while rural nesters relied on marine organisms. As we expected individual variation in foraging habits within nesting location, we characterized each captured gulls' diet using stable isotope and fatty acid analyses of their red blood cells. To test their problem-solving abilities, we presented the sampled birds with a horizontal rendition of the string-pull test, a foraging puzzle often used in animal cognitive studies. The isotopic and fatty acid profiles of urban nesters indicated a diet comprising primarily anthropogenic food, whereas the profiles of rural nesters indicated a high reliance on marine organisms. Despite the gulls' degree of access to urban foraging habitat not predicting solving success, birds with biochemical profiles reflecting anthropogenic food (less DHA and a higher carbon-13 ratio in their red blood cells) had a greater probability of solving the string-pull test. These results suggest that experience foraging on anthropogenic food is the main explanatory factor leading to successful problem-solving, while regular consumption of omega-3s during incubation appears inconsequential.

Tracer movements in a straight uniform flow: New equations for the advective part considering the distortion of flow lines around the well.

Methods for interpreting tracer tests often rely on equations assuming a natural regional flow which is straight and uniform. The main purpose of this project was to develop more realistic equations for the advective part of contaminant transport, by including the flow lines distortion occurring in the vicinity of the injection well. The complex potential of the flow during a tracer test was calculated by superimposing the complex potential of a natural, straight and uniform flow distorted by the presence of a passive well, and the complex potential of a radial flow corresponding to an isotropic injection alone. The equations were developed for a horizontal plan and the calculated complex potential yielded a groundwater velocity field, and after that a formula connecting the position of the advancing front of the tracer plume to the injection duration. These new equations were then tested with numerical simulations. A two-dimensional aquifer plan was modeled and set in order to numerically solve particle tracking and travel time computation of the moving front within a reasonable calculation time. This model provided a comparison of times needed to fully recover the tracer plume previously injected, the one calculated with the new equations and the one calculated with former equations neglecting the impact of the well presence on the groundwater flow field. The results showed that the new equations are significantly more precise, in particular when the injection rate is sufficiently low compared to the natural regional flow rate, with a relatively large well diameter and in the vicinity of the injection well. Three different plume shapes could be visualized numerically, and those shapes depend on the value of a parameter △ which compares the velocity component caused by the injection in the well and the component caused by the natural regional flow.

Clinical Usefulness of Retropulsion Tests in Persons with Mild to Moderate Parkinson's Disease.

People with Parkinson's disease (PwPD) have an increased risk for falls and near falls. They have particular difficulties with maintaining balance against an external perturbation, and several retropulsion tests exist. The Unified PD Rating Scale item 30 (UPDRS30) is the most common, involving an expected shoulder pull. Others recommend using an unexpected shoulder pull, e.g., the Nutt Retropulsion Test (NRT). We aimed to evaluate the clinical usefulness of these tests for detecting future fallers. By using two different golden standards related to self-reported prospective falls and near falls over 6 months following two different time points with 3.5 years between, we estimated sensitivity/specificity, Youden index, predictive values, and likelihood ratios for each test. The different time points yielded a different prevalence of falls and near falls, as well as different predictive values. When comparing the performance of the NRT and UPDRS30 for detecting future fallers, we found that the NRT consistently performed better than UPDRS30. However, neither test exhibited optimal performance in terms of predictive values and associated likelihood ratios. Our findings speak against using either of these tests as a single assessment for this purpose and support previous recommendations of using a multifactorial approach when targeting balance problems in PwPD.

The Choice of Leg During Pull Test in Parkinson's Disease: Not Mere Chance.

Background: Parkinson's disease (PD) starts asymmetrically and it maintains a certain degree of asymmetry throughout its course. Once functional disability proceeds, people with PD can change their dominant hand due to the increased disease severity. This is particularly true for hand dominance, while no studies have been performed so far exploring the behavioral changes of lower limb utilization in PD according to the lateralized symptom dominance. In the current study, we aim to track the foot preference of participants with PD to respond to the Pull Test. Methods: Forty-one subjects suffering from PD, with a H&Y scale ≤ 2, were recruited. A motor evaluation was performed, including the motor part of the MDS-UPDRS, its axial and lateralized scores (for more and less affected side), two Timed Tests, namely Time to Walk a standard distance (TW, in seconds) and Time Up and Go Test (TUG, in seconds), and the Pull Test. The preferred foot (right or left) involved in the step backward was recorded. Thirty-seven healthy controls underwent a motor assessment which included the Pull Test and the Timed Tests. Both participants with PD and controls were right-handed. To evaluate the relationship between the response to Pull-Test and PD-symptoms, subjects with PD were further divided into two groups: (1) Right more affected side (Right-MAS), and (2) Left more affected side (Left-MAS). Results: Both groups of subjects with PD (Right-MAS and Left-MAS) during the Pull Test shifted significantly their leg use preference toward the opposite side than the more affected side: Right-MAS used preferentially their left leg (71%) and vice versa (p < 0.001). The limb preference shift was especially true for Left-MAS group that almost invariably used their right, dominant leg to respond to the Pull Test (95%). Similar results were obtained comparing people with PD and Controls. Conclusions: This study shows that the limb used to respond to the Pull Test generally predicts the contralateral side of worse PD involvement. As the disease takes place, it prevails over hemispheric dominance: right-handed subjects with left side PD-onset and worse lateralization tend to be hyper-right-dominant, while right-handed subjects with right side PD-onset and worse impairment tend to behave as left-handers. Lateralization of symptoms in PD is still a mysterious phenomenon; more studies are needed to better understand this association and to optimize tailored rehabilitation programs for people with PD.

Association of Trichorhinophalangeal Syndrome and Loose Anagen Syndrome: A Case Report.

Trichorhinophalangeal syndrome (TRPS) is an autosomal dominant disease characterized by trichologic, craniofacial, and musculoskeletal abnormalities. Predominant clinical features include a pear-shaped nose with bulbous tip, long philtrum, protruding ears, and sparse hair on both the scalp and the lateral third of the eyebrows. Cone-shaped epiphyses are a common radiographic finding. Loose anagen syndrome (LAS) is a sporadic or autosomal dominant condition due to abnormalities in the hair's anchoring mechanism. It mostly affects children, who usually have reduced hair length, as well as hair that is easily plucked without pain. Recent contributions regarding trichoscopic findings of LAS have been made, describing rectangular black granular structures as a typical feature. An association between TRPS and LAS has been mentioned by hair experts, but no reports documenting this have been published. This case demonstrates the co-existence of both conditions in a patient with characteristic phenotypic traits of TRPS and LAS.

A new solution to transient single-well push-pull test with low-permeability non-Darcian leakage effects.

An accurate solute transport model is critical to the interpretation of single-well push-pull (SWPP) test. Previous studies of SWPP test generally consider solitary aquifer that is confined by impermeable layers. Also, existing solutions for solute transport in aquifer-aquitard systems only consider the injection phase and over-simplify the flow field by assuming uniformly distributed velocity in the aquitard. In this study, we developed a numerical model with Dirichlet boundary condition for SWPP test affected by leakage described by a low-permeability non-Darcian expression involving a threshold pressure gradient (I0). Our SWPP test model considered transient flow in multi-phases, which include injection, chase, rest and extraction phases. Finite-difference scheme was adopted to solve the models of flow and solute transport. The results indicate that an increasing hydraulic diffusivity leads to a greater peak value of breakthrough curve (BTC) while a medium with larger grain size results in less estimation error when using steady-state flow model to interpret the transient SWPP test. Additionally, A greater I0 makes the solute stored in aquitard more difficult to be extracted out due to dispersion dominance, which results in higher BTC values. For the purpose of application, a lumped dimensionless index called the non-Darcian index (NDI) was proposed to quantify the overestimation degree by neglecting leakage, and the underestimation degree by accounting for Darcian leakage, when interpreting the SWPP test with low-permeability non-Darcian leakage. The long-term slope of breakthrough curve coupled with the NDI can be employed to determine the cases in which the low-permeability non-Darcian leakage should be considered.

Efficacy of platelet-rich plasma in androgenetic alopecia patients.

BACKGROUND: Androgenetic alopecia (AGA), a patterned hair loss in both males and females, is a commonly occurring disease worldwide. Conventionally, no curative or satisfactory treatment is available for this condition. Therefore, in the current study, we aim to use platelet-rich plasma (PRP) as an alternative treatment option for the AGA patients. MATERIALS AND METHODS: A total of 30 patients (20 men and 10 women) with AGA were included in the study between February 2017 and November 2017. Blood (9 cc) from each AGA patient was collected in 10 cc syringe, and PRP was isolated using commercially available kit under sterilized conditions. Isolated PRP was injected in the bald areas of scalp of AGA patients. The whole procedure was repeated after one month (two treatment sessions), and patients were followed for six months. The efficacy of PRP for restoration of hair was assessed using parameters such as hair density, terminal to vellus hair ratio, photographs, pull test, physician global assessment score, and patient global assessment score. RESULTS: Mean hair density on first visit (before treatment) was 34.18 ± 14.36/cm2 which was increased to 50.20 ± 15.91/cm2 after 6 months of first treatment (P value <0.05). On a scale of three, mean scores of physician and patient global assessments were 1.45 ± 0.57 and 1.60 ± 0.62, respectively. Mean percentage reduction of hair pulled was 29.2% (P value <0.05) after PRP treatment. Terminal to vellus hair ratio was increased in 60% of patients after PRP therapy. No remarkable adverse effects were noted in patients. CONCLUSION: Results showed that PRP is an effective treatment option in androgenetic alopecia as indicated by higher hair density, satisfactory physician and patient global assessment scores, and increase in terminal to vellus hair ratio.

The effect of autologous activated platelet-rich plasma injection on female pattern hair loss: A randomized placebo-controlled study.

BACKGROUND: Hair is an essential part of a woman's appearance and attractiveness. This is reflected in the predominantly psychological morbidity that can be associated with female pattern hair loss. Platelet-rich plasma(PRP) has been used in numerous fields of medicine. Recently, PRP has received growing attention as a potential therapeutic tool for hair loss. OBJECTIVE: To evaluate the efficacy and safety of autologous platelet-rich plasma in the treatment of female pattern hair loss. MATERIALS AND METHODS: Thirty female patients with female pattern hair loss were randomly assigned to receive autologous PRP injection into a selected area, and another area was injected with normal saline as a placebo. Sessions were performed weekly for a maximum total of four sessions. Patients were followed up 6 months after the end of last session. The outcome was assessed both subjectively and objectively. RESULTS: There was a statistical significant difference between PRP and placebo areas (P<.005) regarding both hair density and hair thickness as measured by a folliscope. The hair pull test became negative in PRP-injected areas in 25 patients (83%) with average number of three hairs. Global pictures showed a significant improvement in hair volume and quality together with a high overall patient satisfaction in PRP-injected sites, and these results were maintained during the 6-month follow- up. CONCLUSION: Platelet-rich plasma injections can be regarded as an alternative for the treatment of female pattern hair loss with minimal morbidity and a low cost-to-benefit ratio.