Membrane Defects Research Articles

Comparative study of conventional internal limiting membrane peeling versus temporal inverted internal limiting membrane flap for large macular hole treatment.

To compare the anatomical, morphological, and functional outcomes of the conventional internal limiting membrane (ILM) peeling versus temporal inverted ILM flap technique for large full-thickness macular holes (FTMHs). Sixty eyes of 60 patients with a minimum base diameter >600 μm were included in this retrospective interventional study. Patients were divided into conventional ILM peeling (Group 1) and temporal inverted ILM flap (Group 2) groups. The hole closure rate, best-corrected visual acuity (BCVA), ellipsoid zone (EZ), and external limiting membrane (ELM) defects were analyzed at baseline and 6 months after surgery. Hole closure was achieved in 24/32 (75.0%) cases of Group 1 and 27/28 (96.4%) cases of Group 2 (P = 0.029). The mean BCVA (logMAR) changed from 1.23 ± 0.47 to 0.70 ± 0.29 logMAR in Group 1 and from 1.03 ± 0.36 to 0.49 ± 0.24 logMAR in Group 2 at 6 months (P < 0.001 in both cases). U-shaped closure was observed in 5 (15.6%) eyes in Group 1 and 19 (67.9%) eyes in Group 2 (P < 0.001). The total restoration rates of ELM and EZ were significantly higher in the temporal inverted ILM flap group (P = 0.002, P = 0.001, respectively). The study results suggested that the FTMH closure rate, recovery of the outer retinal layers, and, consequently, the post-operative BCVA were better with the temporal inverted ILM flap technique than with the conventional ILM peeling for larger than 600 μm macular holes.

Freiberg`s disease of lesser metatarsals treated with bone grafting and autologous matrix induced chondrogenesis (AMIC) membrane – A series of 10 cases

BackgroundFreiberg’s infraction is osteonecrosis of lesser metatarsal heads most commonly affecting adolescent females. They usually present with pain and swelling of the forefoot. MRI is useful investigation in the early diagnosis. It is a self-limiting disease and the main stay of treatment is non operative. Surgery is indicated in failed conservative management which include open debridement, cheilectomy, micro fracture, osteotomies and excision arthroplasty with varying success. MethodsA retrospective analysis of ten patients with Freiberg`s disease of the lesser metatarsals treated with open debridement, microfracture, bone grafting and application of AMIC (Autologous Matrix induced Chondroplasty) membrane was carried out. The patients were followed up to five years and the outcome measures were scored using Manchester-Oxford Foot Questionnaire (MOxFQ) and EQVAS best health scores. ResultsThe mean age was 42.7 years and follow-up time was 36.4 months. The most common site was second metatarsal, eight (80%) followed by third metatarsal, two (20%). The mean base line MOxFQ was 72.5 (95% CI- 45 ± 100) which improved to 42.5 (95%CI- 2.5 ± 82.5) at one year. The mean baseline VAS improved from 26.4(10.2 ± 42.6) to 30.3 (95%CI- 2.1 ± 58.5) at one year. The mean MOxFQ and VAS at the end of 36 months was 31.4(95%CI-6.6 ± 57.2) and47.3(4.3 ± 80.3) respectively. ConclusionsOpen debridement of the Freiberg`s disease combined with microfracture of the defect, bone grafting and application of AMIC membrane shows reliable functional and radiological outcomes at short term follow up.

Membrane integrity monitoring on laboratory scale: Impact of test cell-induced damage on membrane selectivity

Defects in the active layer of reverse osmosis (RO) membranes play a crucial role in the passage of virus particles and microbial surrogates through the membrane systems. Prior research indicates that not only defects in the active layer but also a mechanical failure in the membrane module can compromise the performance of full-scale RO spiral wound systems. However, there have been no studies on the microbial passage in coupon-scale testing systems for highly selective RO membrane characterization on a laboratory scale. The capability of test cells to introduce defects on the membrane surface via contact zones is recognized for the first time in this study. This work focuses on membrane defects introduced by the sealing mechanism of the coupon-scale test. We show how defects arise at points of contact between the membrane, the O-rings, and the test cell body, occurring in both commercially available test cells as well as in-house developed test cells. These defects cause a marked decrease in membrane selectivity, compared to spiral-wound elements housing the same membranes. Membrane integrity was assessed by measuring the passage of viruses and fluorescent markers. We demonstrate that in almost all cases, detectable virus concentrations were found in the permeate due to non-selective transport through defects in the membrane. Failure to account for this non-selective transport leads to an overestimation of achievable selectivity by a factor of two or more, as seen in previously published studies. Lastly, we propose modifications to test cell design that reduce contact zones thus potentially safeguarding the membrane's selectivity.

Inner limiting membrane bridges within Bruch's membrane defects in pathological myopia.

The purpose of the study was to examine peculiarities of the inner limiting membrane (ILM) in axially elongated eyes. The histomorphometric study included human globes enucleated due to reasons such as painful secondary angle-closure glaucoma or malignant uveal melanomas. Using light microscopy, we searched for regions with ILM-specific features in association with a marked axial elongation. Out of 279 eyes (279 patients) (mean age: 61.8 ± 13.9years; axial length: 25.5 ± 3.1mm (range: 20.0-37.0mm)), two eyes (axial length: 30mm and 34mm, respectively) showed one region and two regions, respectively, characterized by ILM presence and absence of all other retinal layers, retinal pigment epithelium, Bruch´s membrane (BM) and choroid. The length of these regions, called ILM-bridges, was 1.06mm, 0.73mm, and 0.62mm, respectively. All ILM-bridges were spatially associated with a larger, underlying BM defect and with localized scleral thinning without a staphylomatous scleral configuration. The distance between the ILM-bridges and the optic disc ranged between 1.92mm and 4.21mm. In univariable analysis, ILM-bridge number increased with longer axial length (beta: 0.19; P = 0.002) and higher BM defect prevalence (beta: 0.21; P = 0.001), while in multivariable analysis, the ILM-bridges number remained to be significantly correlated only with a higher prevalence of BM defect (beta: 0.15; P = 0.048). ILM-bridges occur in eyes with pathologic myopia in spatial association with underlying, larger BM defects. They may be due to an axial elongation-associated local stretching and rupture of all other retinal layers, caused by the BM defect-related enlargement of the retinal undersurface. Future studies may explore whether these histologic observations support the notion of the ILM having a relatively high biomechanical strength against myopic stretching-associated forces.

Genetic nephrotic syndrome associated with disturbed function of glomerular slit membrane and podocyte cytoskeleton in children.

Genetic nephrotic syndrome is caused by pathogenic variants in genes encoding proteins necessary for the stability and functionality of the glomerular filtration barrier. To date, more than 70 genes associated with steroid-resistant nephrotic syndrome have been identified. We review the clinical and molecular aspects of genetic nephrotic syndrome with a particular focus on genes associated with slit membrane and podocyte cytoskeleton defects. Sanger sequencing and next-generation sequencing are widely used in the identification of novel gene variants and help us gain a better understanding of the disease. Despite these findings, therapy is mainly supportive and focused on the reduction of proteinuria and management of chronic kidney disease with an unfavorable outcome for a significant proportion of cases. Positive therapeutic effects of immunosuppressive drugs have been reported in some patients; however, their long-time administration cannot be generally recommended. Personalized treatment based on understanding the distinct disease pathogenesis is needed. With this, it will be possible to avoid harmful immunosuppressive therapy and improve outcomes and quality of life for pediatric patients suffering from genetic nephrotic syndrome.

Inherited hemolytic anemias in children

Inherited hemolytic anemia is one of the most commonly seen anemias encountred in the pediatric age, especially in Türkiye, where consanguineous marriages are common. Inherited hemolytic anemias mainly includes hemoglobinopathies, erythrocyte membrane defects and enzyme defects. Hemolytic anemias have a wide etiology and clinical spectrum with acquired and hereditary causes in childhood. Always a careful self and family history review and synthesis of physical examination and laboratory findings are vital for differential diagnosis. Therefore, physicians should be competent about prevention methods and early diagnosis markers.

In-situ interfacial crosslinking of NH2-MIL-53 and polyimide in MOF-incorporated mixed matrix membranes for efficient H2 purification

The key issue to avoiding the degradation of gas separation performance due to the formation of non-selective defects in mixed matrix membranes (MMMs) is to promote the interfacial compatibility of fillers with the continuous polymer matrix. In this work, we report an efficient and simple method to prepare MMMs by crosslinking metal organic frameworks (MOF) and polyamic acid (PAA) (the precursor of polyimide), in which NH2-MIL-53 particles are thermally crosslinked with the PAA during the imidization reaction, forming hydrogen bonds and amide bonds at the interface. The resulting enhanced interfacial force greatly improves the interfacial compatibility of the membrane, which is also more conducive to the separation of H2/CO2. Among the as-prepared samples, PI-NH2-MIL-53 MMMs loaded with 30 wt% MOF exhibit excellent H2 permeability (384.1 Barrer) and H2/CO2 permeation selectivity (16.7), which are significantly higher than the 2008 Robeson upper bound. The membranes also display enhanced mechanical characteristics and long-term stability. Here, building strong interactions on MOF/polymer MMMs using an in-situ cross-linking strategy to enhance membrane performance provides a new opportunity to develop advanced membranes for industrial gas separation applications.

ATN grading system in a dome‐shaped macula and ridge shaped macula high lymyopic cohort

AbstractPurpose: The purpose of this study was to analyse the ATN grading in highly myopic patients with dome‐shaped macula (DSM) and ridge‐shaped macula (RSM).Methods: This was a cross‐sectional, noninterventional study. 57 eyes of 38 different patients were included. They were classified as DSM or RSM based on the number of radial scans affected on the swept‐source optical coherence tomography (SS‐OCT) (12 = DSM; 12 = RSM). All patients underwent a complete ophthalmological examination in addition to SS‐OCT. They were graded using the ATN system for myopic maculopathy by 2 masked retina specialists that assessed the atrophic (A), tractional (T), and neovascular (N) components. As complementary measurements, age, axial length (AL) and best corrected visual acuity (BCVA) were collected. Height and orientation of the macular bulge and the presence of Bruch's membrane defects, scleral perforating vessels and staphyloma were recorded.Results: Out of total 57 eyes, 13 eyes (22.8%) were classified as DSM. Regarding the atrophic component (A), there were statistically significant differences between groups, with DSM group showing a greater stage of atrophy (predominantly stage A3 in 69.2% of the sample) compared to the RSM group (predominantly stage A2 in 61.3% of the sample) (p &lt; 0.05). As for the tractional (T) and neovascular (N) components, there were no significant differences between groups. The presence of Bruch's membrane defects was more frequently seen in DSM (p &lt; 0.05).Conclusions: DSM group showed more Bruch's membrane defects and a greater stage of the atrophy component, based on the ATN grading system, compared with RSM group. As Bruch's membrane may have biomechanical properties in terms of strength, the defects found around the macula, added to the major atrophic component, may be a cause of a local relaxation that induce a central bulge forming the dome.

Myopic macular Bruch's membrane defects

AbstractPurpose: To examine peculiarities of macular Bruch's membrane defects (BMD) in axially elongated eyes.Methods: Using light microscopy, enucleated human globes were histomorphometrically.Results: The study included 247 eyes (axial length: 20.0–37.0 mm). BMDs were detected in 15 (6.1%) eyes (axial length: 30.6 ± 2.4 mm) (1.9 ± 0.9 BMD/eye with BMDs), located in the macular region in 10 eyes. Mean BMD size was 1.93 ± 1.62 mm (range: 0.22 mm–6.24 mm). Prevalence and size of BMDs were associated with longer axial length (OR: 1.52; p = 0.001) and higher prevalence of scleral staphyloma (OR: 16.3; p &lt; 0.001). BMD width was smaller than the defect width in the overlying retinal pigment epithelium (RPE) layer (p = 0.003) and larger than the length of a defect in the overlying inner nuclear layer (0.43 ± 0.76 mm; p = 0.008) and the width of an inner limiting membrane bridge (0.13 ± 0.33 mm; p = 0.001). Choriocapillaris thickness (8.8 ± 5.0 μm vs. 7.9 ± 3.2 μm; p = 0.94), BM thickness (3.1 ± 0.6 μm versus 3.0 ± 0.5 μm; p = 0.43) and RPE cell density (31.6 ± 8.4 cells/480 μm vs. 27.4 ± 8.8 cells/480 μm; p = 0.051) did not differ significantly between the region at the BDM margin and neighbouring regions. The sclera was thinner in the BDM region than in the neighbouring regions (0.28 ± 0.19 mm vs. 0.36 ± 0.13 mm; p = 0.006).Conclusions: BMDs as hallmark of myopic macular degeneration are characterized by a larger defect in the overlying RPE layer, smaller defects in the overlying retinal outer nuclear layer and inner nuclear layer, localized scleral thinning and an association with scleral staphylomas. Thickness of the choriocapillaris and density of the RPE cell layer, both absent within the BDMs, do not differ between the BMD margin and neighbouring regions. The results suggest an association between BDMs and absolute scotomas, stretching of the overlying retinal nerve fiver layer, an axial elongation‐associated stretching effect as aetiology of the BDMs, and a biomechanical role BM may play.

Inner limiting membrane bridges within Bruch's membrane defects in pathological myopia

AbstractPurpose: To examine peculiarities of the inner limiting membrane (ILM) in axially elongated eyes.Methods: The histomorphometric study included human globes enucleated due to reasons such as painful secondary angle‐closure glaucoma or malignant uveal melanomas. Using light microscopy, we searched for regions with ILM‐specific features in association with a marked axial elongation.Results: Out of 279 eyes (279 patients) (mean age: 61.8 ± 13.9 years; axial length: 25.5 ± 3.1 mm (range: 20.0–37.0 mm)), two eyes (axial length: 30 mm and 34 mm, respectively) showed one region and two regions, respectively, characterized by ILM presence and absence of all other retinal layers, retinal pigment epithelium, Bruch's membrane (BM) and choroid. The length of these regions, called ILM‐bridges, was 1.06, 0.73, and 0.62 mm, respectively. All ILM‐bridges were spatially associated with a larger, underlying BM defect and with localized scleral thinning without a staphylomatous scleral configuration. The distance between the ILM‐bridges and the optic disc ranged between 1.92 and 4.21 mm. In univariable analysis, ILM‐bridge number increased with longer axial length (beta: 0.19; p = 0.002) and higher BM defect prevalence (beta: 0.21; p = 0.001), while in multivariable analysis, the ILM‐bridges number remained to be significantly correlated with a higher prevalence of BM defect (beta: 0.15; p = 0.048).Conclusions: ILM‐bridges are a hallmark of pathologic myopia and occur in spatial association with underlying, larger BM defects. ILM‐bridges may be due to a local stretching and rupture of all other retinal layers, caused by the BM defect‐related enlargement of the retinal underground, with the ILM as a basal membrane presenting the highest resistance against the stretching‐associated biomechanical force.

Directional growth of quasi-2D Cu2O monocrystals on rGO membranes in aqueous environments.

The preparation technology of unconventional low-dimensional Cu2O monocrystals, which exhibit specific crystal planes and present significantly unique interfacial and physicochemical properties, is attracting increasing attention and interest. Herein, by integrating a high-temperature oxidation process under vacuum and a pure-water incubation process under ambient conditions, we propose the self-assembled growth and synthesis of quasi-two-dimensional Cu2O monocrystals on reduced graphene oxide (rGO) membranes. The prepared Cu2O crystals have a single (110) crystal plane, regular rectangular morphology, and potentially well conductivity. Experimental and theoretical results suggest that this assembly is attributed to the pre-nucleation clusters aggregation and directional attachment of Cu and O on the rGO membranes in aqueous environment and cation-π interactions between the (110) crystal plane of Cu2O and rGO surface. Our findings offer a potential avenue for the discovery and design of advanced low-dimensional single-crystal materials with specific interfacial properties in a pure aqueous environment.

PP61 Plugging the Gap of Fetoscopy in Congenital Diaphragmatic Hernia Pregnancies: Value for Money?

IntroductionFetoscopic endoluminal tracheal occlusion (FETO) for congenital diaphragmatic hernia (CDH) fetuses increases the neonatal survival rate. However, FETO also increases the number of preterm prelabour rupture of membranes (PPROM) and preterm deliveries (PTDs) as fetal membrane defects after fetoscopy do not spontaneously heal. To solve this issue, an advanced sealing plug is being developed. Through early-stage health economic modelling, we estimated the potential value of this innovative plug in terms of costs and effects and determined the properties for it to become cost-effective.MethodsWe applied early-stage health economic modelling to the case of performing FETO in singleton pregnant women whose fetus is prenatally diagnosed with CDH. We simulated a cohort of women using a state-transition model over a 45-year time horizon. In our best-case scenario analysis, we compared the current care strategy to a perfect plug strategy, which reduces PPROM and PTDs by 100 percent, to determine the maximum quality-adjusted life years (QALYs) gained and costs saved. Using threshold analysis, we determined the minimum percentage of reduction in PPROM and PTDs for the plug to be considered cost-effective. Model parameters’ impact on outcomes was investigated in a sensitivity analysis.ResultsOur model indicated that a perfect plug strategy would yield an additional 1.94 QALYs at a cost decrease of EUR 2,554 per patient per year. These values were strongly influenced by the percentage of very preterm deliveries. Threshold analysis showed that, for EUR 500 per plug, the plug strategy needs a minimum relative reduction of 1.83 percent in PPROM and PTDs (i.e., PPROM: 47.50 to 46.63 %, PTDs: 71.50 to 70.19 %) to be cost-effective.ConclusionsOur model-based approach showed clear potential for the plug strategy when applied in the context of FETO for CDH fetuses, as only a small reduction in PPROM and PTDs is needed for the plug to be cost-effective. Its value is expected to be even higher when used in conditions suffering from more very preterm deliveries. Continuation of investment in the innovation’s research and development seems to provide value for money.

Express method for detecting defects in polysulfone hollow fiber membranes with different porous structures

A new method of electroprometry has been proposed that allows continuous investigation of extended sections of a hollow fiber membrane. Samples of polysulfone hollow fiber membranes with different porous structures were obtained: finger-shaped and spongy. These membranes were examined on a laboratory electroprometric apparatus with continuous scanning along the length of the hollow fiber membrane sample at a high voltage of 15 kV. Defects were detected in these hollow fiber membranes by the proposed method of electroporometry, the nature of which was then investigated using scanning electron microscopy. A correlation was found between the size of the detected defect and the magnitude of the corona discharge current signal: the larger the defect, the greater the absolute value of the current. It is shown that the proposed method can be effectively used as an express method to study the homogeneity of the porous structure of hollow fiber membranes in extended areas with geometrical localization of possible defects.

Lack of Low-affinity Phosphate Transporter Pho91 Alters Lipid Metabolism in Yeast Saccharomyces cerevisiae

Objective: The current study tries to elucidate the impact of low-affinity Pi transporter Pho91 (using pho91Δ cells) on lipid metabolism and cellular organelles morphology (mitochondria and vacuole) in yeast Saccharomyces cerevisiae. Methods: The lipid profile was performed using thin layer chromatography (TLC), and the membrane defect was determined using DiOC6 staining, lipid droplets (LDs) were observed by Nile red staining, mitochondrial morphology was observed using aconitase 1 GFP, vacuolar morphology was studied by FM4-64 staining and were performed with the aid of laser scanning fluorescent microscope. Findings: Pho91 is a low-affinity phosphate (Pi) transporter in the vacuoles that functions under Pi-rich conditions, but its role in lipid metabolism is largely unknown. In this study, we used defined synthetic complete media (SC). The deletion of Pho91 depicted a moderate growth defect but increased the major phospholipids PC, PE, and PI. Alterations in the membrane phospholipids resulted in defective membrane morphology. In pho91 mutant (pho91Δ), the neutral lipids TAG and SE were increased and stored as LDs. The LD numbers were increased in pho91Δ cells than in WT cells. Altered phospholipids also defective mitochondrial morphology and enlarged vacuoles in pho91 deletion. Novelty: In the absence of low-affinity Pi transporter pho91, it increases phospholipid, neutral lipid levels, LD numbers, and impacted mitochondria along with vacuolar structures. Keywords: Phosphate transporter; Low affinity; Phospholipids; Neutral lipids; Lipid droplets

On the issue of effective engraftment of tissues in the plastic of the tympanic membrane

For a long time for otolaryngologists, the issues of identifying and treating such a formidable disease as chronic suppurative otitis media (CSOM) have been topical. This disease still haunts many specialists, as it leads to acquired hearing loss in people of working age. Only in the last ten years, the number of children of younger age groups with already manifested acquired hearing loss has increased. Along with the correct and timely diagnosis, it is very important to cure this disease once and for all, since exacerbations often disrupt not only the performance, but also the quality of life of the patient. The gold standard for the treatment of patients with CHSO is surgical – tympanoplasty. In the process of studying the pathological process in chronic suppurative otitis media and methods of its more effective surgical treatment, the results of tympanoplasty were analyzed. An illustrative clinical example has been chosen, with the help of which it is possible to trace all the stages of surgical intervention in chronic suppurative otitis media. An otoscopic examination was carried out at several stages of observation of this patient, as well as the determination of auditory function. The presented clinical case shows step by step the effectiveness of the scheme of surgical treatment and postoperative management. Thus, these steps are applicable to any myringoplasty with tympanic membrane defects of any size. It is tympanoplasty and control in the postoperative period that makes it possible to completely close the defect of the tympanic membrane and prevent chronic otitis media from recurring.

Interfacial Tailoring of Polyether Sulfone-Modified Silica Mixed Matrix Membranes for CO2 Separation.

In this work, in situ polymerization of modified sol-gel silica in a polyether sulfone matrix is presented to control the interfacial defects in organic-inorganic composite membranes. Polyether sulfone polymer and modified silica are used as organic and inorganic components of mixed matrix membranes (MMM). The membranes were prepared with different loadings (2, 4, 6, and 8 wt.%) of modified and unmodified silica. The synthesized membranes were characterized using Field emission electron scanning microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, thermogravimetric analyzer, and differential scanning calorimetry. The performance of the membranes was evaluated using a permeation cell set up at a relatively higher-pressure range (5-30 bar). The membranes appear to display ideal morphology with uniform distribution of particles, defect-free structure, and absence of interfacial defects such as voids and particle accumulations. Additionally, the CO2/CH4 selectivity of the membrane increased with the increase in the modified silica content. Further comparison of the performance indicates that PES/modified silica MMMs show a promising feature of commercially attractive membranes. Therefore, tailoring the interfacial morphology of the membrane results in enhanced properties and improved CO2 separation performance.

Post-synthetic modification of MOFs to enhance interfacial compatibility and selectivity of thin-film nanocomposite (TFN) membranes for water purification

Efficient discrimination of ions and small neutral contaminants remains a challenge for polyamide thin-film nanocomposite (TFN) water separation membranes due to the presence of interfacial defects and particle-agglomeration-induced nonselective voids in the polyamide layer. In this work, highly selective TFN membranes were successfully fabricated by leveraging post-synthetic modifications of (3-glycidyloxypropyl)triethoxysilane (GPTES) and trimesoyl chloride (TMC) on MIL-101(Cr)–NH2 MOF filler nanoparticles. GPTES modification suppresses particle agglomeration during interfacial polymerization for membrane formation by forming a stable particle suspension in the organic monomer solution, while TMC-induced in situ chemical crosslinking between filler particles and polyamide addresses the phase compatibility and interfacial issues at the filler–polyamide interface. The resulting TFN membranes show high NaCl, MgCl2, Na2SO4, and MgSO4 rejections of 99.0–99.6% at 150 psi with a water permeance of 0.9 L m−2 h−1 bar−1. Compared to the thin-film composite (TFC) control membrane, the incorporation of the MOF particles yields a 53.0% and 24.5% increase in water permeance and NaCl rejection. Importantly, the TFN membranes also exhibit excellent rejections to small neutral contaminants such as PEG200 (99.2% rejection) and boric acid (89.0% rejection at a pH value of 7.5) at a relatively low pressure of 150 psi, which is higher than the respective value obtained by the commercial Dow SW30XLE TFC control membrane at the same conditions. The outstanding long-term performance stability revealed the robust structure of the MOF TFN membranes. Our results demonstrate a facile strategy to effectively control particle agglomeration and interfacial defects in polyamide TFN membranes by manipulating the surface chemistry of the filler nanoparticles, which can be applied to the fabrication of effective TFN membranes with molecular level size-exclusion selectivity.

Parameters of Iron Metabolism in Patients with Iron Deficiency Anemia and Erosive Lesions of the Gastroduodenal Zone

The most common disease in the world is erosive-ulcerative lesions of the gastroduodenal zone (EULGZ). These are chronic polyetiological, recurrent diseases with disruption of the neuro-endocrine and humoral mechanisms that regulate the secretory-trophic process in the gastroduodenal zone with the development of ulcers. In this disease, ulcers have different localization and clinical course, significantly reduce the quality of life, affect work capacity and personal life. Lack of timely diagnosis and treatment can have adverse consequences. The objective: to analyse the characteristics of clinical and metabolic disorders in iron deficiency anemia (IDA) and its combination with EULGZ in order to develop the methods for assessing the disease severity, optimizing diagnostics and treatment tactics. Materials and methods. The observation group included 26 patients (15 men and 11 women) with iron-deficiency anemia (IDA) on background of EULGZ with localization of ulcerative defects of the mucous membrane in the stomach or duodenal bulb. The diagnosis of IDA was verified on the basis of changes in the basic characteristics of clinical manifestations (signs of anemic hypoxia and sideropenic syndrome), specific changes in peripheral blood and indicators of iron metabolism. Patients with IDA and EULGZ, were examined by endoscopic methods, underwent ultrasound and, if necessary, radiological examination. The control group included 35 primary donors (16 women and 19 men), who underwent two laboratory tests for hepatitis B and C, as well as HIV infection/AIDS. All examined donors underwent a comprehensive examination of peripheral blood and determined biochemical indicators. The indicators of iron metabolism were determined in all participants: iron content in the blood serum (IS), total iron-binding capacity of the blood serum (TIBS). The index of unsaturated iron-binding capacity of blood serum was calculated as the difference between TIBS and IS. The coefficient of transferrin saturation with iron was determined as the ratio of the content of IS to TIBS. The content of transferrin was determined according to the TIBS indicator, ferritin – by the radiometric method. Results. Peripheral blood indicators in primary donors and morphometric changes in peripheral blood in patients with IDA were analyzed. The results of investigations of the indicators of iron exchange in blood serum are presented: iron concentration, total iron-binding capacity of serum and the degree of saturation of serum with iron. It was found that male donors have significantly higher levels of iron and ferritin in blood serum compared to female donors. The dynamic of changes in peripheral blood parameters in patients with IDA caused by long-term blood loss due to EULGZ during the treatment process is shown. Treatment of the EULGZ led to the significant changes of such indicators as the number of erythrocytes, hemoglobin concentration, erythrocyte indices towards normalization. The normalization of the reticulocyte count was observed on the 90th day of treatment. The detected changes in the number of platelets in patients with IDA due to EULGZ were observed in the absence of active bleeding from the digestive tract. Conclusions. As a result of the progression of IDA due to the erosive-ulcerative lesions of the gastroduodenal zone, the imbalance of iron metabolism deepens, serious disorders of iron metabolism develop, especially in the content of plasma ferritin. Patients with IDA caused by long-term blood loss as a result of EULGZ, should be prescribed a drug for oral use containing ferrous sulfate with a mucosa-protective effect at a dose of 2 mg/kg per day, followed by a decreased dose after normalization of the serum ferritin level.

The compound effect of irradiation and familial pseudohyperkalemia on potassium leak from red blood cells.

Familial pseudohyperkalemia (FP) is a rare asymptomatic condition characterized by an increased rate of potassium leak from red blood cells (RBC) on refrigeration. Gamma irradiation compromises RBC membrane integrity and accelerates potassium leakage. Here, we compared the effect of irradiation, applied early or late in storage, on FP versus non-FP RBC. Five FP and 10 non-FP individuals from the National Institute for Health Research Cambridge BioResource, UK, and three FP and six non-FP individuals identified by Australian Red Cross Lifeblood consented to the study. Blood was collected according to standard practice in each center, held overnight at 18-24°C, leucocyte-depleted, and processed into red cell concentrates (RCC) in Saline Adenine Glucose Mannitol. On Day 1, RCC were split equally into six Red Cell Splits (RCS). Two RCS remained non-irradiated, two were irradiated on Day 1 and two were irradiated on Day 14. RBCs were tested over cold storage for quality parameters. As expected, non-irradiated FP RCS had significantly higher supernatant potassium levels than controls throughout 28 days of storage (p < .001). When irradiated early, FP RCS released potassium at similar rates to control. When irradiated late, FP RCS supernatants had higher initial post-irradiation potassium concentration than controls but were similar to controls by the end of storage (14 days post-irradiation). No other parameters studied showed a significant difference between FP and control. FP does not increase the rate of potassium leak from irradiated RBCs. Irradiation may cause a membrane defect similar to that in FP RBCs.

Modeling Mechanical Behavior of Membranes in Proton Exchange Membrane Water Electrolysis

The reliability of a proton exchange membrane water electrolysis (PEMWE) depends significantly on the long-term mechanical stability of the membrane due to its relatively low mechanical robustness. Membrane defects can be caused, for example, by severe mechanical stress in the critical gap between the cell frame and the porous transport layer (PTL). In this work the mechanical stresses and strains are quantified for such scenarios by using a finite element (FE) analysis which is applied to a simplified model setup.Nafion® is used as a standard material for the membrane and an appropriate material model is implemented into a FE software. The used parameters are based on and validated by experimental data from tensile tests to ensure matching with real PEMWE systems. The validated material model is used in the cell simulation to identify resulting stresses and strains during assembly and operation. In accordance with experimental experience, no critical states were identified. Furthermore, differential pressure up to 10 bar in the model could not cause any significant change compared to deformations resulting from boundary conditions for balanced pressure operation. Varying the gap size between the cell frame and PTL resulted in a buckling in the simulated membrane for sizes of 0.3 mm and more during membrane swelling.