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Nida Salman Yazdani,1 Kaniz Amna Haider,2 Amna Khan,2 Syed Ali Jaffar Zaidi,2 Akbar Rajani,1 Imran Nisar,2 Fyezah Jehan,2 Zahra Hoodbhoy2 1Research and Programs, VITAL Pakistan Trust, Karachi, Pakistan; 2Department of Paediatrics and Child Health, the Aga Khan University, Karachi, PakistanCorrespondence: Zahra Hoodbhoy, Aga Khan University, Stadium Road PO Box 3500, Karachi, 74800, Pakistan, Tel +92-3343481179, Email zahra.hoodbhoy@aku.eduPurpose: To understand pregnant women’s experience with midwifery-led antenatal care services using the Respectful Maternity Care charter in primary health centers in Karachi, Pakistan.Methods: This cross-sectional study was at Rehri Goth and Ibrahim Hyderi, two peri-urban communities in Karachi, Pakistan, where women receive antenatal care services. All pregnant women in their third trimester who consented during the study period were included. The participants were asked about access to care, antenatal care experience, person-centered approach, and general satisfaction with the facility using a pre-designed questionnaire. These themes were mapped onto the universal Respectful Maternity Care charter. Descriptive statistics were used to summarize the findings in each of these themes. Multivariable logistic regression techniques to determine the relationship between the dependent and independent variables.Results: There were 904 women who agreed to participate in this study during January to December 2021. Majority of the women (94%, n=854) were satisfied with the operating hours and cleanliness. More than 90% of the women reported positive experiences regarding privacy, respectful treatment by midwives, and non-discriminatory care. However, 40% (n=362) of the women reported not receiving adequate information and informed consent before a medical procedure, while 65% (n=587) reported poor counseling for birth preparedness. Maternal age, women’s occupation, women’s education, and parity were found to be significantly associated with respect provided, satisfaction with counseling and the consent process.Conclusion: This study reported satisfaction of pregnant women with the facility’s ambiance, respect, and care; however, poor communication skills regarding consent and antenatal counseling were reported. The findings suggest the need for more efficient strategies, such as regular respectful maternity care and technical training to strengthen midwife-patient interactions and enhance overall satisfaction, thus improving maternal and newborn outcomes.Keywords: antenatal care, patient satisfaction, Respectful Maternity Care, Pakistan

Category: Midfoot/Forefoot; Other Introduction/Purpose: Morton’s neuroma (MN) is a very common compressive neuropathy of the interdigital nerve. Non- operative management is recommended initially and many therapies have been described. Cryoablation has shown promising results, however there are limited published studies in the literature. The purpose of this study was to assess the safety and efficacy of Cryoablation in patients with MN. A secondary aim was to evaluate post-procedure MRI appearances. Methods: A retrospective analysis was completed for 24 MN treated between June 2021 and September 2022. All patients had refractory MN symptoms after previous US guided steroid and LA injection within the previous year. Three patients also had refractory symptoms after prior alcohol ablation. Cryoablation was performed as a single outpatient procedure under continuous US monitoring and local anesthesia with 1 cycle for average of 2 minutes. Telephone follow up by radiology department with a 0–10 visual analogue scale (VAS) score was performed at 6 weeks and 3 months post-ablation. The patients were also encouraged to submit patient reported outcomes to a British Foot and Ankle Society (BOFAS) online scoring database as facilitated by the surgical team. Post-ablation MRI was performed to evaluate for post-procedure appearances at various intervals between 3 to 14 months. Results: 24 MN were treated. The mean size of MN treated was 12.3mm. Technical success was 100% and all patients tolerated the procedure well under local anesthesia. Mean pre-procedure VAS pain score was 8, which reduced to 1 at 6 weeks, and 2 at 3 months follow up in the treated MN. There is high patient satisfaction with 20 cases (83%) very satisfied. Four cases had various persistent symptoms and would want to have it done again (17%). Post-ablation MRI showed various bone and soft tissue changes in the ablation zone. There were two cases of fibrosis in the intermetatarsal space and one residual neuroma observed on MRI, although the patients were asymptomatic in the ablation site. No complications occurred e.g. infection, fracture or thermal injury. Conclusion: In this small series, ultrasound guided Cryoablation was deemed safe and effective treatment for MN. Clinical advantages of the procedure are good patient tolerance, single outpatient procedure, high patient satisfaction and reduced risk of scarring or residual neuroma. Further controlled prospective studies would be beneficial.

There are still areas around the world suffer from severe shortage of freshwater supplies. Desalination technologies are not widely used due to their high energy usage, cost, and environmental damaging effects. In this study, a mathematical model of single-bed adsorption desalination system using silica gel-water as working pair is developed and validated via earlier experiments. A very good match between the model predictions and the experimental results is recorded. The objective is to reveal the factors affecting the productivity of fresh water and cooling effect in the solar adsorption system. The proposed model is setup for solving within the commercially-available software (Engineering Equation Solver). It is implemented to solve the mass and heat balance equations for the adsorbent bed, condenser, and evaporator components. At a typical temperature of 89 °C and flow rate of 30 m3/sec for the hot water entering the bed, the following results are reported: (a) the specific daily water production of 1.89 m3 /ton of silica gel/ day, (b) coefficient of performance of 0.32, and (c) specific cooling power of 40.82 W/kg of silica gel. The concentration of salt (X) in the product (desalinated water) has been set with value of 0.5 gm/kg to be suitable for drinking and irrigation. The salt concentration in the evaporator is estimated to be 4.611 gm/kg during the overall adsorption process. The results from this study should be of wide interest for the field of solar water desalination and air-conditioning.

Abstract In this paper, a new optical fiber corrosion sensor based on metallic bilayers is described. The detection region is located at a fiber end facet and we present simulations as well as experimental results in controlled lab conditions for Ti(10 nm)/Al(10 nm) and Ni(5 nm)/Al(5 nm) bilayers. We perform the characterization of the device by numerical simulations using the COMSOL Multiphysics software, and with an analytical model, which makes use of the Fresnel equations. According to the simulations, the change in the reflected optical signal over time is related to variations in the thickness of the metallic films by the corrosive process and, consequently, the corrosion rate in each metal of the bilayer can be obtained. Upon the simulation results, sensor devices were fabricated by depositing thin metallic films on the cleaved facet of the optical fiber using the sputtering method. We show that the use of a metallic bilayer as a transducer, instead of a monolayer, improves the sensor measuring interval (20 ± 1 nm) and provides information about the corrosion rate along the corrosion process.

Abstract This article presents the proposed structure and the simulation results from analytical and numerical modeling of two corrosion sensor elements in D-shaped optical fiber: one based on the lossy mode resonance (LMR) effect and the other based on the effect of surface plasmon resonance (SPR). In the first sensor element, a bilayer of titanium dioxide – aluminum (TiO2-Al) is deposited on the D-shaped region, operating in LMR conditions, while, in the second sensor element, an aluminum (Al) monolayer is deposited under D-shaped region, operating in SPR condition. The sensor elements can operate separately, enabling simultaneous two-parameter measurements at two different points, or they can operate in cascade configuration, increasing the operating range and sensitivity of the sensor set. The D-shaped region of the optical fiber is modeled with an analytical model based on the Fresnel formulation, and also with a numerical model, which uses the finite element method with the COMSOL Multiphysics 5.2 software. The transmission of light through the D-shaped region causes peculiar variations in each light polarization in each sensor element, depending on the metal thickness. Both regions are subject to a corrosive environment. The sensor elements are evaluated separately and in cascade configuration, using polarized and nonpolarized light. Finally, the obtained results show two resonance valleys for the same operating wavelength, resulting in a higher operating range with high sensitivity, compared to other corrosion sensor structures found in the literature.

Objective: Unusual clinical course Background: Classical hemophilia A, an X-linked recessive disorder, is characterized by an inability to produce factor VIII in normal quantities. This condition, also leading to factor IX deficiency, underpins the bleeding disorder known as hemophilia A. Among the complications of this illness, spontaneous retroperitoneal hematoma is rare but can be associated with congenital coagulopathies such as von Willebrand disease or hemophilia A. This type of spontaneous internal bleeding has been the subject of a limited number of studies. Case Report: A 38-year-old man with a known diagnosis of hemophilia A presented to the Emergency Department exhibiting acute pain in the right lower abdomen. A computed tomography scan of the abdomen identified a rightsided retroperitoneal mass, suspected to be a hematoma. Within 7 h after admission, the patient experienced significant drops in the hemoglobin level and platelet count. He was administered packed red blood cells, fresh frozen plasma, and platelet transfusions prior to transfer to the Intensive Care Unit. There, he was treated with factor VIII and recombinant factor VIIa, coupled with stringent monitoring. Following clinical and laboratory findings and stabilization, he was discharged with specific medications, and a follow-up appointment was scheduled. Conclusions: Spontaneous retroperitoneal hematoma in patients with hemophilia A is a rare and grave emergency. This case underscores the need for precise diagnostic approaches, tailored management strategies, and vigilant surveillance to prevent and mitigate the potentially life-threatening complications associated with spontaneous hemorrhage in this population. [ABSTRACT FROM AUTHOR]

Background: Ocular manifestations of inflammatory bowel disease (IBD) considered being the most common extraintestinal complication. Eventually, early detection and management improve the patient's quality of life as well as prevent potentially visually threatening complications. Objectives: To assess the prevalence and pattern of ocular manifestations among patients with inflammatory bowel disease during the COVID-19 pandemic. Materials and Methods: Cross-sectional study was performed using anonymous online surveys were administered which included the participant's demographics, prevalence and pattern of IBD intestinal and ocular manifestations, precipitating factors, and quality of life. Data were analyzed using (SPSS) version 20 (Armonk, NY: IBM Corp.). Chi-squared test Mann–Whitney and Kruskal–Wallis tests were applied. A P < 0.05 was considered statistically significant. Informed consent and ethical approval were obtained. Results: A total of 216 participants responded to the survey with 50.50% of females and 49.50% were male. About 90.3% of the participants had their GIT symptoms start before their eye symptoms. Almost two-thirds of the participants, (68.5%) suffered from frequent severe bowel symptoms that prevented them from carrying out work and/or perform the normal daily activity. Furthermore, one-third of the participants (31.6%) are unemployed and described a positive family history (32.8%). More than 75% of participants described eye symptoms associated with the intestinal disease activity which range from mild self-limiting to more severe ones that required hospital visits (50%). Although, majority of participants (90.00%) did not routinely receive official referral to ophthalmologist. The non-significant difference was found between the presence of eye symptoms and participant's gender, marital status, educational level, stress, and smoking habits. Conclusion: Most of the IBD patients suffered from significant ocular manifestations with frequent hospital visits. Misdiagnosis and/or inadequate management negatively affect the quality of life of IBD patients during the COVID-19 pandemic. Risk-based Ophthalmic screening strategy may reduce the impact of IBD.

We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations.

Background Intrapulmonary pharmacokinetics may better explain response to tuberculosis (TB) treatment than plasma pharmacokinetics. We explored these relationships by modeling bacillary clearance in sputum in adult patients on first-line treatment in Malawi. Methods Bacillary elimination rates (BER) were estimated using linear mixed-effects modelling of serial time-to-positivity in mycobacterial growth indicator tubes for sputum collected during the intensive phase of treatment (weeks 0–8) for microbiologically confirmed TB. Population pharmacokinetic models used plasma and intrapulmonary drug levels at 8 and 16 weeks. Pharmacokinetic-pharmacodynamic relationships were investigated using individual-level measures of drug exposure (area-under-the-concentration-time-curve [AUC] and C max) for rifampicin, isoniazid, pyrazinamide, and ethambutol, in plasma, epithelial lining fluid, and alveolar cells as covariates in the bacillary elimination models. Results Among 157 participants (58% human immunodeficiency virus [HIV] coinfected), drug exposure in plasma or alveolar cells was not associated with sputum bacillary clearance. Higher peak concentrations (C max) or exposure (AUC) to rifampicin or isoniazid in epithelial lining fluid was associated with more rapid bacillary elimination and shorter time to sputum negativity. More extensive disease on baseline chest radiograph was associated with slower bacillary elimination. Clinical outcome was captured in 133 participants, with 15 (11%) unfavorable outcomes recorded (recurrent TB, failed treatment, or death). No relationship between BER and late clinical outcome was identified. Conclusions Greater intrapulmonary drug exposure to rifampicin or isoniazid in the epithelial lining fluid was associated with more rapid bacillary clearance. Higher doses of rifampicin and isoniazid may result in sustained high intrapulmonary drug exposure, rapid bacillary clearance, shorter treatment duration and better treatment outcomes. [ABSTRACT FROM AUTHOR]

The study characterized the bacterial microbiome in the vagina of lactating dairy water buffaloes using denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene. This research was conducted to serve as baseline study for future studies on vaginal microbiome and its possible effect on production and reproduction of dairy water buffaloes. Molecular characterization of 16S rRNA genes of the different band after DGGE revealed that 15 (46.87%), 15 (46.87%) and two (6.25%) of isolated microbiomes had 100%, 90-99% and below 89% sequence homology, respectively. Out of the 32 isolates sequenced, the top three most isolated bacteria were Comamonas sp., E. coli, and Acidovorax sp. with nine (28.13%), four (12.5%) and three (9.36%) isolates, respectively. The other bacteria isolated with two (6.25%) isolates each were Stenotrophomas maltophila, Klebsiella pneumoniae, Microbacterium sp., Pedobacter sp. and one (3.16%) each of Enterococcus faecium, Lysinibacillus capsici, Enterobacter, Variovorax, Flavobacterium, Alpha Proteobacterim and an Uncultured bacteria clone. This was the first study of characterization of the 16s rRNA gene of the vaginal microbiome of dairy water buffaloes in the Philippines using PCR-DGGE. [ABSTRACT FROM AUTHOR]

There are still areas around the world suffer from severe shortage of freshwater supplies. Desalination technologies are not widely used due to their high energy usage, cost, and environmental damaging effects. In this study, a mathematical model of single-bed adsorption desalination system using silica gel-water as working pair is developed and validated via earlier experiments. A very good match between the model predictions and the experimental results is recorded. The objective is to reveal the factors affecting the productivity of fresh water and cooling effect in the solar adsorption system. The proposed model is setup for solving within the commercially-available software (Engineering Equation Solver). It is implemented to solve the mass and heat balance equations for the adsorbent bed, condenser, and evaporator components. At a typical temperature of 89 °C and flow rate of 30 m³/sec for the hot water entering the bed, the following results are reported: (a) the specific daily water production of 1.89 m³ /ton of silica gel/ day, (b) coefficient of performance of 0.32, and (c) specific cooling power of 40.82 W/kg of silica gel. The concentration of salt (X) in the product (desalinated water) has been set with value of 0.5 gm/kg to be suitable for drinking and irrigation. The salt concentration in the evaporator is estimated to be 4.611 gm/kg during the overall adsorption process. The results from this study should be of wide interest for the field of solar water desalination and air-conditioning. [ABSTRACT FROM AUTHOR]

This article presents the proposed structure and the simulation results from analytical and numerical modeling of two corrosion sensor elements in D-shaped optical fiber: one based on the lossy mode resonance (LMR) effect and the other based on the effect of surface plasmon resonance (SPR). In the first sensor element, a bilayer of titanium dioxide - aluminum (TiO2-Al) is deposited on the D-shaped region, operating in LMR conditions, while, in the second sensor element, an aluminum(Al) monolayer is deposited under D-shaped region, operating in SPR condition. The sensor elements can operate separately, enabling simultaneous twoparameter measurements at two different points, or they can operate in cascade configuration, increasing the operating range and sensitivity of the sensor set. The D-shaped region of the optical fiber is modeled with an analytical model based on the Fresnel formulation, and also with a numerical model, which uses the finite element method with the COMSOL Multiphysics 5.2 software. The transmission of light through the D-shaped region causes peculiar variations in each light polarization in each sensor element, depending on the metal thickness. Both regions are subject to a corrosive environment. The sensor elements are evaluated separately and in cascade configuration, using polarized and nonpolarized light. Finally, the obtained results show two resonance valleys for the same operating wavelength, resulting in a higher operating range with high sensitivity, compared to other corrosion sensor structures found in the literature. [ABSTRACT FROM AUTHOR]

In this paper, a new optical fiber corrosion sensor based on metallic bilayers is described. The detection region is located at a fiber end facet and we present simulations as well as experimental results in controlled lab conditions for Ti(10 nm)/Al(10 nm) and Ni(5 nm)/Al(5 nm) bilayers. We perform the characterization of the device by numerical simulations using the COMSOL Multiphysics software, and with an analytical model, which makes use of the Fresnel equations. According to the simulations, the change in the reflected optical signal over time is related to variations in the thickness of the metallic films by the corrosive process and, consequently, the corrosion rate in each metal of the bilayer can be obtained. Upon the simulation results, sensor devices were fabricated by depositing thin metallic films on the cleaved facet of the optical fiber using the sputtering method. We show that the use of a metallic bilayer as a transducer, instead of a monolayer, improves the sensor measuring interval (20 ± 1 nm) and provides information about the corrosion rate along the corrosion process. [ABSTRACT FROM AUTHOR]

Category: Midfoot/Forefoot; Other Introduction/Purpose: Morton's neuroma (MN) is a very common compressive neuropathy of the interdigital nerve. Non- operative management is recommended initially and many therapies have been described. Cryoablation has shown promising results, however there are limited published studies in the literature. The purpose of this study was to assess the safety and efficacy of Cryoablation in patients with MN. A secondary aim was to evaluate post-procedure MRI appearances. Methods: A retrospective analysis was completed for 24 MN treated between June 2021 and September 2022. All patients had refractory MN symptoms after previous US guided steroid and LA injection within the previous year. Three patients also had refractory symptoms after prior alcohol ablation. Cryoablation was performed as a single outpatient procedure under continuous US monitoring and local anesthesia with 1 cycle for average of 2 minutes. Telephone follow up by radiology department with a 0–10 visual analogue scale (VAS) score was performed at 6 weeks and 3 months post-ablation. The patients were also encouraged to submit patient reported outcomes to a British Foot and Ankle Society (BOFAS) online scoring database as facilitated by the surgical team. Post-ablation MRI was performed to evaluate for post-procedure appearances at various intervals between 3 to 14 months. Results: 24 MN were treated. The mean size of MN treated was 12.3mm. Technical success was 100% and all patients tolerated the procedure well under local anesthesia. Mean pre-procedure VAS pain score was 8, which reduced to 1 at 6 weeks, and 2 at 3 months follow up in the treated MN. There is high patient satisfaction with 20 cases (83%) very satisfied. Four cases had various persistent symptoms and would want to have it done again (17%). Post-ablation MRI showed various bone and soft tissue changes in the ablation zone. There were two cases of fibrosis in the intermetatarsal space and one residual neuroma observed on MRI, although the patients were asymptomatic in the ablation site. No complications occurred e.g. infection, fracture or thermal injury. Conclusion: In this small series, ultrasound guided Cryoablation was deemed safe and effective treatment for MN. Clinical advantages of the procedure are good patient tolerance, single outpatient procedure, high patient satisfaction and reduced risk of scarring or residual neuroma. Further controlled prospective studies would be beneficial. [ABSTRACT FROM AUTHOR]

Abstract This work presents the operation of a spontaneous Raman scattering-based distributed fiber-optic temperature sensor using a commercial OTDR and a standard EDFA optical amplification in a simple and economic scheme. We present both theoretical and experimental results regarding the sensor's sensitivity and performance in seven different configurations, using OTDR pulses of 100 ns to 4000 ns for two detection regions, in the beginning and ending sections of a 27 km standard single-mode fiber sensor link. The results reveal the trade-off between sensor sensitivity, resolution and range, regarding the use of different OTDR pulsewidths.

This paper presents experimental results, approximate analytical formulations, and numerical simulation results to analyze the reflectance from a metalized fiber tip under corrosion, which is part of a corrosion sensor. Moreover, the dynamics of corrosion on a thin metallic film is modeled computationally by considering a proposed roughness fitting function to consider the evolution of film thickness and shape during the corrosion process. For this modeling, COMSOL Multiphysics is used to simulate the optical signal reflected from the transducer element of the sensor. The simulation results for the optical signal reflected from a rough metallic film are compared with experimental and analytical results. The results reveal that the corrosion process generates an inhomogeneous metallic structure that allows the occurrence of surface plasmon resonance, and the proposed simple surface roughness model can be used to describe the dynamic process of corrosion of an aluminum film that is deposited on the end-facet of an optical fiber. [ABSTRACT FROM AUTHOR]

The effects of terrain, soil moisture heterogeneity, subsurface properties, and water table dynamics on the development and behavior of the atmospheric boundary layer are studied through a set of idealized numerical experiments. The mesoscale atmospheric model Advanced Regional Prediction System (ARPS) is used to isolate the effects of subsurface heterogeneity, terrain, and soil moisture initialization. The simulations are initialized with detailed soil moisture distributions obtained from offline spin-ups using a coupled surface-subsurface model (ParFlow-CLM). In these idealized simulations, we observe that terrain effects dominate the planetary boundary layer (PBL) development during early morning hours, while the soil moisture signature overcomes that of terrain during the afternoon. Water table and subsurface properties produce a similar effect as that of soil moisture as their signatures (reflected in soil moisture profiles, energy fluxes, and evaporation at the land surface) can also overcome that of terrain during afternoon hours. This is mostly clear for land surface energy fluxes and evaporation at the land surface. We also observe the coupling between water table depth and planetary boundary layer depth in our cases is strongest within wet-to-dry transition zones. This extends the findings of previous studies which demonstrate the subsurface connection to surface energy fluxes is strongest in such transition zones. We investigate how this connection extends into the atmosphere and can affect the structure and development of the convective boundary layer. [ABSTRACT FROM AUTHOR]

We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations. [ABSTRACT FROM AUTHOR]

This work investigates the role of terrain and subsurface heterogeneity on the interactions between groundwater dynamics and land surface energy fluxes using idealized simulations. A three-dimensional variably saturated groundwater code (ParFlow) coupled to a land surface model (Common Land Model) is used to account for both vertical and lateral water and pressure movement. This creates a fully integrated approach, coupling overland and subsurface flow while having an explicit representation of the water table and all land surface processes forced by atmospheric data. Because the water table is explicitly represented in these simulations, regions with stronger interaction between water table depth and the land surface energy balance (known as critical zones) can be identified. This study uses simple terrain and geologic configurations to demonstrate the importance of lateral surface and subsurface flows in determining land surface heat and moisture fluxes. Strong correlations are found between the land surface fluxes and water table depth across all cases, including terrain shape, subsurface heterogeneity, vegetation type, and climatological region. Results show that different land forms and subsurface heterogeneities produce very different water table dynamics and land surface flux responses to atmospheric forcing. Subsurface formation and properties have the greatest effect on the coupling between the water table and surface heat and moisture fluxes. Changes in landform and land surface slope also have an effect on these interactions by influencing the fraction of rainfall contributing to overland flow versus infiltration. This directly affects the extent of the critical zone with highest coupling strength along the hillside. Vegetative land cover, as seen in these simulations, has a large effect on the energy balance at the land surface but a small effect on streamflow and water table dynamics and thus a limited impact on the land surface-subsurface interactions. Although climate forcing has a direct effect on water table dynamics and feedbacks to the land surface, in this study it does not overcome that of subsurface heterogeneity and terrain. [ABSTRACT FROM AUTHOR]

Both genetic and environmental factors contribute to multiple sclerosis, the most common neurodegenerative disorder with onset in young adults. The objective of the current study is, based on the hypothesis that environmentally predisposed individuals are at risk for multiple sclerosis, to investigate whether they also carry genetic variants within the vitamin D machinery. Using medical files and DNA samples from 583 trios (a patient and both parents) of the French Multiple Sclerosis Genetics Group as well as data from the French Statistics Bureau, we aimed to assess whether: (1) a seasonality of birth was observed in French multiple sclerosis patients; (2) three single nucleotide polymorphisms within the promoter region of the vitamin D receptor were associated with multiple sclerosis susceptibility; and (3) the combination of a high risk month of birth and vitamin D receptor polymorphisms were correlated to multiple sclerosis incidence. We observed a significantly reduced number of individuals born in November who were later diagnosed as multiple sclerosis patients. However, we found no association between the three studied vitamin D receptor polymorphisms and multiple sclerosis. In conclusion, our data suggest that high levels of vitamin D during the third trimester of pregnancy could be a protective factor for multiple sclerosis. [ABSTRACT FROM AUTHOR]