Parietal epithelial cells maintain the epithelial cell continuum forming Bowman's space in focal segmental glomerulosclerosis

In the glomerulus, Bowman's space is formed by a continuum of glomerular epithelial cells. In focal segmental glomerulosclerosis (FSGS), glomeruli show segmental scarring, a result of activated PECs invading the glomerular tuft. The segmental scars interrupt the epithelial continuum. However, non-sclerotic segments seem to be preserved even in glomeruli with advanced lesions. We studied the histology of the segmental pattern in Munich Wistar Frömter (MWF) rats, a model for secondary FSGS. Our results showed that matrix layers lined with PECs cover the sclerotic lesions. These PECs formed contacts with podocytes of the uninvolved tuft segments, restoring the epithelial continuum. Formed Bowman's spaces were still connected to the tubular system. Furthermore, in biopsies of patients with secondary FSGS we also detected matrix layers formed by PECs, separating the uninvolved from the sclerotic glomerular segments. While PECs have a major role in the formation of glomerulosclerosis, we showed that in FSGS, PECs also restore the glomerular epithelial cell continuum that surrounds Bowman's space. This process may be beneficial and indispensable for glomerular filtration in the uninvolved segments of sclerotic glomeruli.

Neonatal Bartter syndrome: A case report from Northern India

Bartter Syndrome is a rare genetic disorder affecting the renal tubular system causing a decreased absorption of sodium and chloride in the thick ascending limb of the Henle loop. Most children present in infancy with complaints of polyuria, polydipsia, vomiting, constipation and failure to thrive while older children present with recurrent episodes of dehydration, muscle weakness and cramps. The present study aimed to demonstrate a case of Bartter syndrome presenting as acute gastroenteritis.

Risk Mitigation and Mapping on Tubular System During Microbial Huff and Puff Injection Coupled with Lean Six Sigma Approach at Field X

Increasing demand of oil in Indonesia is in contrast with the decreasing oil production every year. Enhanced oil recovery (EOR) has become one of the most favorable method in maximizing the production of mature fields with various applications and research has been done on each type, especially microbial EOR (MEOR). “X” field is a mature oil field located in South Sumatra that has been actively producing for more than 80 years and currently implementing MEOR using huff and puff injection. However, there are some potential risks regarding MEOR processes that may inhibit the production by damaging the well’s tubular system, particularly microbially induced corrosion (MIC). This study reviews the risk mitigation and mapping to prevent corrosion on tubular system during MEOR huff and puff processes, equipped with the approach of Lean Six Sigma.The mitigation and mapping process follow the framework of define, measure, analyze, improve, and control (DMAIC). It starts with defining the problem using supplier-input-process-output-customer (SIPOC) diagram after all the field data necessary has already been collected, then measuring the corrosion rate model using ECE™ software as well as conducting sensitivity analysis of the fluid rates. The analyze phase involves constructing fishbone diagram to identify the root causes, comparison with industry’s specification and standard, and analysis of chromium effect on corrosion rates. Further simulation is conducted to support the analysis and to ensure the improvements and sustainability of the design selection.Based on the simulation results, the normal corrosion rate ranging from 0.0348 – 0.039 mm/year and the pH is around 4.03 – 5.25, while the ±30% fluid rate sensitivity results shown that the change of water flowrate is more sensitive than oil flowrate with the corrosion rate approximately 0.0275 – 0.048 mm/year. The fishbone diagram identifies that material selection and environmental condition as the main root causes, then corrosion resistant alloy (CRA) is used in the tubing string to prevent corrosion in the future by using super 13Cr martensitic steel (modified 2Ni-5Mo-13Cr) as the most suitable material. Further simulation on chromium content supports the selection that corrosion rate can be reduced by adding the chromium content in the steel. The completion design is then capped with choosing the Aflas® 100S/100H fluoro-elastomer as the optimum material for packer and sealing. Overall, the Lean Six Sigma approach has been successfully applied to help the analysis in this study.

A new approach to the determination of tubular membrane capacitance: passive membrane electrical properties under reduced electrical conductivity of the extracellular solution

The tubular system of cardiomyocytes plays a key role in excitation-contraction coupling. To determine the area of the tubular membrane in relation to the area of the surface membrane, indirect measurements through the determination of membrane capacitances by electrophysiological measurements are currently used in addition to microscopic methods. Unlike existing electrophysiological methods based on an irreversible procedure (osmotic shock), the proposed approach uses a reversible short-term intermittent increase in the electrical resistance of the extracellular medium. The resulting increase in the lumen resistance of the tubular system makes it possible to determine separately capacitances of the tubular and surface membranes from altered capacitive current responses to subthreshold voltage-clamped rectangular pulses. Based on the analysis of the time course of capacitive current, computational relations were derived which allow to quantify elements of the electrical equivalent circuit of the measured cardiomyocyte including both capacitances. The exposition to isotonic low-conductivity sucrose solution is reversible which is the main advantage of the proposed approach allowing repetitive measurements on the same cell under control and sucrose solutions. In addition, it might be possible to identify changes in both surface and tubular membrane capacitances caused by various interventions. Preliminary experiments in rat ventricular cardiomyocytes (n = 10) resulted in values of the surface and tubular capacitances 72.3 ± 16.4 and 42.1 ± 14.7 pF, respectively, implying the fraction of tubular capacitance/area of 0.36 ± 0.08. We conclude that the newly proposed method provides results comparable to those reported in literature and, in contrast to the currently used methods, enables repetitive evaluation of parameters describing the surface and tubular membranes. It may be used to study alterations of the tubular system resulting from various interventions including associated cardiac pathologies.

INFLUENCE OF SUBCLINICAL KETOSIS IN COWS ON FORMATION OF COLOSTRAL IMMUNITY IN CALVES

The health of the newborn depends entirely on the state of the mother’s body throughout the pregnancy. Ensuring optimal conditions for keeping pregnant animals is based, first of all, on adequate feeding and ensuring the sanitary and hygienic conditions of the environment. The cow’s body undergoes a great load during the transition period, which begins 3 weeks before calving and lasts for six weeks. When the technology of feeding and housing is violated, during this period, metabolic disorders often occur in cows, which are manifested by increased production of ketones. It is known that the development of immunity in the early postnatal period in a calf largely depends on the timely feeding of colostrum. Maternal immunoglobulins from colostrum enter the systemic circulation of the newborn in the small intestine through the tubular system of epithelial cells by pinocytosis.The aim of the study is to study the effect of subclinical ketosis in mothers cows on the formation of colostral immunity in calves born from them.For the study, pregnant cows 3-6 years old were selected 3-7 days before delivery. Urine and blood samples were taken from the cows. In order to identify subclinical ketosis in cows, urine was tested for ketones. According to the results of the study, two groups of 10 animals were formed – in the first group (experimental) the level of ketone bodies in the urine ranged from 1.8 to 3.7 mmol/l, in the second group (control) ketones were not found in the urine. Immediately after calving, portions of colostrum were taken from the cows, and blood was taken from newborn calves a day after the first colostrum was fed. The content of immunoglobulins was studied in skim colostrum and in the blood serum of newborn calves. In the blood serum of day-old calves, the content of total protein was also determined by the biuret method, albumin – by the photometric method with bromcresol green.According to the results of the study, a decrease in the classes of immunoglobulins G, M and A was found in the blood serum of cows before calving by 19.1-23.5%, in colostrum – by 23.7-34.4%, and in the blood serum of day old calves – by 21.7-27.6%. The decrease in IgM concentration was determined to the greatest extent. Subclinical ketosis of mothers had practically no effect on the content of albumin in the blood of calves.

HUMAN iPSC ENGINEERED CARDIAC TISSUE PLATFORM FAITHFULLY MODELS IMPORTANT CARDIAC PHYSIOLOGY

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CM) may provide an important bridge between animal models and intact human myocardium. Fulfilling this potential is hampered by their relative immaturity. hiPSC-CMs grown in monolayer culture lack a t-tubular system, have rudimentary intracellular calcium-handling systems, express predominantly embryonic sarcomeric protein isoforms, and preferentially use glucose as energy substrate. Culturing hiPSC-CM in a 3D environment and the addition of nutritional, pharmacologic and electromechanical stimuli have proven to be beneficial for maturation. We present an assessment of a model in which hiPSC-CMs and hiPSC-derived cardiac fibroblasts are co-cultured in a 3D fibrin matrix to form human engineered cardiac tissue constructs (hECT).The hECT respond to physiological stimuli, including stretch, frequency and β-adrenergic stimulation, develop a t-tubular system, and demonstrate calcium-handling and contractile kinetics that compare favorably with ventricular human myocardium. Transcript levels of genes involved in calcium-handling and contraction are increased. These markers of maturation become more robust over a short period of time in culture (6 weeks vs. 2 weeks in hECT). A comparison of the hECT molecular and performance variables with those of human cardiac tissue and other available engineered tissue platforms is provided to highlight strengths and weaknesses of these preparations. Important and noteworthy aspects of this human cardiac model system are its reliance on 'off-the-shelf' equipment, ability to provide detailed physiological performance data, and the ability to achieve a relatively mature cardiac physiology without additional nutritional, pharmacological and electromechanical stimuli that may elicit unintended effects on function.

Platelet Ultrastructure in Familial Platelet Disorder with Associated Myeloid Malignancy (FPDMM)

The familial platelet disorder with associated myeloid malignancy (FPDMM) is an autosomal dominant platelet disorder, caused by germline RUNX1 mutations, with predisposition to develop hematologic malignancies, especially acute myeloid leukemia. In many of the FPDMM families reported, the platelet defect was a delta-storage-pool disease (d-SPD) which can also be found without leukemia propensity. However, it has not been studied whether the two types of d-SPD have a common nature. Platelet ultrastructure, previously very little studied, may be one of the aspects to be analyzed to solve this question. We analyzed the ultrastructural characteristics of platelets in 5 members of a family with FPDMM. The family included three generations and all affected members had a RUNX1 deletion: chr21:36349450-36572837 (Rio-Machin et al. Nat Commun 2020;11:1044). None of the patients studied had developed leukemia at the time of the platelet study. We compared the results with those of 24 patients with d-SPD non-associated with leukemia and with those of 15 healthy individuals. Platelets were processed by transmission electron microscopy by standard methods. On the electron micrographs, morphometric analysis of the following structures was performed: 1) Platelets: size and shape, 2) Intraplatelet corpuscular structures (dense granules, alpha granules, mitochondria, lipid droplets): size and number (per platelet and per square micrometer of platelet area), 3) Surface-connected canalicular system (SCS): mean area of individual channel sections and mean percentage of the total SCS area with respect to the platelet area, 4) Glycogen masses: total area with respect to the platelet area. The morphological traits of the platelets and organelles measured above were also evaluated and the dense granules were classified into 4 different types depending on the appearance of their solid core (Weiss et al. Br J Haematol 1993;83:282). The dense tubular system and other ultrastructural characteristics were evaluated by morphology only. The main features of the platelet ultrastructure in patients with FPDMM were (Fig 1, Table 1): 1) slight increase in platelet size while preserving the discoidal shape, 2) moderate reduction in the number of dense granules, which showed a reduced proportion of type 1 granules (with the solid core occupying more than 50 % of the granule) and an increased proportion of type 2 and type 3 granules, with a solid core reduced or fragmented respectively, 3) marked increase and dilatation of SCS with some elements filled by a substance of unknown origin, 4) moderate increase in dense tubular system with occasional complex formation. The platelet ultrastructure was similar to that described in the non-associated d-SPD group (Pujol-Moix et al. Haematologica 2000;85:619) although there were some differences (Table 1): in FPDMM platelets the dense granules were less reduced but more dysmorphic, and the SCS, equally dilated, contained a substance that was not observed in the d-SPD platelets. Given that all the findings described belong to the same family, it would be necessary to evaluate the platelet ultrastructure in additional families and extend the study to other characteristics of d-SPD. Only in this way, it would be possible to know to what extent the platelet defect of FPDMM and that of non-associated d-SPD shared a pathogenic mechanism. Disclosures No relevant conflicts of interest to declare.