Diaphragm Membrane Research Articles

Advances in the biology and genetics of the podocytopathies: implications for diagnosis and therapy.

Etiologic factors and pathways leading to altered podocyte phenotype are clearly numerous and involve the activity of different cellular function. To focus on recent discoveries in podocyte biology and genetics and their relevance to these human glomerular diseases, named podocytopathies. Genetic mutations in genes encoding for proteins in the nucleus, slit diaphragm, podocyte cytoplasm, and cell membrane are responsible for podocyte phenotype and functional abnormalities. Podocyte injury may also derive from secondary stimuli, such as mechanical stress, infections, or use of certain medications. Podocytes can respond to injury in a limited number of ways, which include (1) effacement, (2) apoptosis, (3) arrest of development, and (4) dedifferentiation. Each of these pathways results in a specific glomerular morphology: minimal change nephropathy, focal segmental glomerulosclerosis, diffuse mesangial sclerosis, and collapsing glomerulopathy. Based on current knowledge of podocyte biology, we organized etiologic factors and morphologic features in a taxonomy of podocytopathies, which provides a novel approach to the classification of these diseases. Current and experimental therapeutic approaches are also discussed.

Tonometric biosensor with a differential pressure sensor for chemo-mechanical measurement of glucose

A tonometric biosensor for glucose was constructed using a chemo-mechanical reaction unit and a differential pressure sensor. The reaction unit was fabricated by using both liquid and gas cells separated by an enzyme diaphragm membrane, in which glucose oxidase was immobilized onto the single (gas cell) side of the dialysis membrane. By applying glucose solution (0, 25.0, 50.0, 100, 150 and 200 mmol/l) into the liquid cell of the chemo-mechanical reaction unit, the pressure in the gas cell decreased continuously with a steady de-pressure slope because the oxygen consumption in the gas cell was induced by the glucose oxidase (GOD) enzyme reaction at the enzyme side of the porous diaphragm membrane. The steady de-pressure slope in the gas cell showed the linear relationship with the glucose concentration in the liquid cell between 25.0 and 200.0 mmol/l (correlation coefficient of 0.998). A substrate regeneration cycle coupling GOD with l-ascorbic acid (AsA: 0, 1.0, 3.0, 10.0 and 50.0 mmol/l; as reducing reagent system) was applied to the chemo-mechanical reaction unit in order to amplify the output signal of the tonometric biosensor. 3.0 mmol/l concentration of AsA could optimally amplify the sensor signal more than 2.5 times in comparison with that of non-AsA reagent.

The spectrum of focal segmental glomerulosclerosis: new insights

Focal segmental glomerulosclerosis (FSGS) is a disease with diverse histologic patterns and etiologic associations. Genetic, toxic, infectious and inflammatory mediators have been identified. This review will focus on new evidence supporting the potential mechanistic basis underlying the histologic variants and their clinical relevance. Evidence from animal models and in-vitro studies suggests that injury inherent within or directed to the podocyte is a central pathogenetic factor. Disruption of signaling from any of the podocyte's specialized membrane domains, including slit diaphragm, apical and basal membranes, or originating at the level of the actin cytoskeleton, may promote the characteristic response of foot process effacement. Irreversible podocyte stress leading to podocyte depletion through apoptosis or detachment is a critical mechanism in most forms of FSGS. In the collapsing variant, podocyte dysregulation leads to podocyte dedifferentiation and glomerular epithelial cell proliferation. Translation studies in humans and new evidence from animal models have provided mechanistic insights into the diverse phenotypes of FSGS.

Topographic Specificity within Membranes of a Single Muscle DetectedIn Vitro

Spinal motor pools project to target muscles forming distinct rostrocaudal topographic maps during development and regeneration. To define the mechanisms underlying these neuromuscular maps we studied the preferential outgrowth of embryonic spinal cord neurites on muscle membranes from different axial positions and explored the role of ephrin A ligands. We found all five ephrin As (EphAs) expressed in serratus anterior, gluteus maximus and diaphragm muscles. In the diaphragm, four of the five ephrin As are expressed as a caudal to rostral gradient. When ephrin A function is disrupted in muscle membranes by deletion of glycosyl-phosphatidylinositol anchored ephrin A ligands with phosphatidylinositol-specific phospholipase C enzyme treatment or by blocking of ephrin A ligands with EphA fusion proteins, or by genetic manipulation leading to ephrin A2/A5 mutant mice, the spinal cord neurites loose their preference for the membranes of corresponding axial position; suggesting a significant role for ephrins in topographic choices made by growing motor neurons. To closely approximate topographic choices presented to embryonic neurites in vivo, neurites within the phrenic motor pool were challenged to make outgrowth choices on membranes of their normal target, the diaphragm muscle. We observed that neurites from rostral cervical segments (C1 and C2) prefer to grow on rostral diaphragm membranes; caudal cervical neurites (C6-C8) choose caudal diaphragm membranes; a transition of positional preference occurs at C4 and this ability is lost in ephrin A2/A5 mutant mice. These results demonstrate for the first time topographical outgrowth of axons from within a motor pool onto a single target muscle in vitro.

Poisoning in ostriches following ingestion of toxic plants - field observations

Data from post-mortem and field studies were obtained that discussed poisoning in ostriches following ingestion of toxic plants. From the notes, all plants studied caused death in ostriches and there was systemic organ damage. Poisoning from Sarcostemma viminale (Melktou) resulted in beak patting, muscular tremors and head flopping, followed by collapse and violent kicking before death. Ingestion of Combretum oatesii (Red wings) seeds from plants in free grazing pastures resulted in vomiting, restlessness, eyelid flicking, collapse and kicking movements. Dichapetalum cymosum (Gifblaar) killed an ostrich after episodes of shaking legs, rapid respiration and bradycardia and hyperaemia of the lungs, liver and kidneys. Poisoning from Senecio sceleratus (Ragwort) caused skin haemorrhages and bleeding in tracheal mucous membranes, the pericardium, diaphragm and interperitoneal membrane. Consumption of drupes from Melia azedarach (Syringa berry) caused muscle tremors, kicking movements and respiratory distress. Lantana camara (Cherry pie) poisoning resulted in extremely inflamed eyes with copious yellow exudates extending down their beaks and onto their necks. Bentonite was administered by gavage at a dose of 5 g/kg. Poisoning in these cases is usually associated with the farmer allowing his/her birds to roam free-range in paddocks in which toxic plants are growing. Toxic plants should be removed from grass cut for hay.

Bioelectronic sniffers for formaldehyde in the gas phase

Two kinds of enzyme electrodes were constructed by immobilizing ALDH or FALDH into a Pt-electrode deposited onto a hydrophilic-polytetrafluoroethylene membrane. A bioelectronic sniffer device for formaldehyde vapor was fabricated by incorporating the enzyme electrode into the reaction unit with both gas- and liquid-compartments separated by a diaphragm membrane. The sensitive area of the electrode was placed onto the diaphragm membrane in the liquid compartment. Gaseous substances in the gas-compartment could diffuse to the electrode through the diaphragm. The amperometric current of the sniffer-device with ALDH and FALDH increased by applying formaldehyde vapor, thus obtaining the calibration range of 10–2000 ppb, including the maximum permitted concentrations (80 ppb) and the human detection limit (410 ppb). In comparison with the outputs obtained by applying other gaseous substances, the sniffer-device with biocatalysts, especially FALDH, indicated high gas-selectivity for formaldehyde vapor.

Bioelectronic sniffer with monoamine oxidase for methyl mercaptan vapor

A bioelectronic sensor for methyl mercaptan (MM) was developed. The biosensor consists of Clark-type dissolved oxygen electrode and a monoamine oxidase type-A (MAO-A) immobilized membrane. In order to amplify the biosensor output, a substrate regeneration cycle caused by coupling the monooxygenase with l-ascorbic acid (AsA) as reducing reagent system was applied. The AsA 10 mmol/l concentration could optimally amplify the sensor output more than 10 times. The MAO-A biosensor was used with AsA to measure MM solution from 0.004 to 4.0 mmol/l, and had good selectivity attributed to enzyme specificity obtained for several substances (triethyl amine, trimethyl amine, dimethyl sulfoxide, dimethyl sulfide, etc.). The biosensor was applied to detect gaseous MM as a bioelectronic sniffer (bio-sniffer) with a reaction unit which had liquid–gaseous compartments separated by a hydrophobic porous polytetrafluoroethylene (PTFE) diaphragm membrane. The tip of the biosensor was placed into the liquid compartment as touching to the PTFE diaphragm membrane. The results of MM vapor measurements showed that the calibration range of the bio-sniffer for MM vapor was from 0.01 to 10 ppm (correlation coefficient: 0.983) and included the human sense of smell level 5 (0.2 ppm).

Bioelectronic detector with monoamine oxidase for halitosis monitoring

Methyl mercaptan (MM) is known as one of the major chemicals of halitosis (bad breath). In this study, a bioelectronic gas sensor (bio-detector) for gaseous MM was developed and was applied to measure halitosis in breath. The bio-detector consisted of a Clark-type dissolved oxygen electrode, a monoamine oxidase type-A (MAO-A) immobilized membrane and a reaction unit that had liquid and gaseous compartments separated by a hydrophobic porous polytetrafluoroethylene (PTFE) diaphragm membrane. The tip of the electrode covered with MAO-A membrane was placed into the liquid compartment as touching to the PTFE diaphragm membrane. In order to amplify the bio-detector output, a substrate regeneration cycle caused by coupling the monooxygenase with l-ascorbic acid as reducing reaction with reagent system, was applied. The results of MM vapor measurements showed the calibration range of the bio-detector for MM vapor was from 0.087 to 11.5 ppm (correlation coefficient: 0.993) and included the human sense of smell level 5 (0.2 ppm). The bio-detector had good selectivity being attributed to enzyme specificity was obtained for several substances (trimethyl amine, ammonia, dimethyl sulfide, etc.). The bio-detector was applied for halitosis measurement. Expired gases in five subjects were sampled every hour and the concentrations of MM in the expired gases were monitored. The output of bio-detector showed behaviour of halitosis level changes in a day such as increasing with passage of time and decreasing after eating.

825 細胞膜を模倣した人工的能動輸送システム(J13-1 生体の熱・物質輸送とその応用(1),J13 生体の熱・物質輸送とその応用,2005年度年次大会)

An artificial active transportation system was constructed by using two funnel type glass tubes separated by an enzyme diaphragm membrane, in which catalase was immobilized onto the single side of the dialysis membrane. By applying hydrogen peroxide (H2O2) solution into the non-enzyme side of the glass tube, the tube pressure at the enzyme side increased continuously. In consequence, an active transportation of hydrogen peroxide through the asymmetric enzyme membrane could induce the pressure increase in the enzyme side tube (max.: 5000 Pa), thus resulting in the discharge of buffer solution from the enzyme-side tube with non-pulsating flow with good repeatability (4.31% of correlation of variation). The tube pressure at the membrane side indicated the linear relationship with the concentration of hydrogen peroxide from 11.8 to 123.6 (mmol/l).

硫化ジメチル用バイオ・スニファに関する研究

A bioelectronic gas-sensor (bio-sniffer) for dimethyl sulfide (DMS) was fabricated by incorporating an enzyme electrode with flavin-containing monooxygenase into a reaction unit with both liquid- and gas-phase cells separated a diaphragm membrane. The bio-sniffer was calibrated against DMS vapor from 2.6 to 147ppm.

Determinants of Vascular Permeability in the Kidney Glomerulus

The human kidneys filter 70 liters of blood plasma every day. The hallmark of almost all kidney diseases, whether acquired or genetic, is the leakage of plasma proteins into the urine because of alterations in the glomerular filtration unit of the kidney. In this regard, the human mutations in nephrin, podocin, alpha-actinin-4, COL4A3, and COL4A5 genes expressed in the glomeruli have been implicated to cause alterations in glomerular filtration apparatus. Nevertheless, the expression of these proteins in relation to each other in mouse models for glomerular vascular leak is unknown. Additionally, within the glomerulus, the central question of whether the primary filtration barrier is the basement membrane or the epithelial slit diaphragm remains ambiguous. Therefore, in this study, we examined the localization and expression of glomerular epithelial slit diaphragm and glomerular basement membrane proteins implicated in glomerular vascular leak using mice deficient in either the alpha3 chain of type IV collagen, the major constituent of glomerular basement membrane, or LMX1B transcription factor, which regulates the expression of key glomerular type IV collagen genes COL4A3 and COL4A4 or nephrin, a glomerular epithelial slit diaphragm-associated protein. This study demonstrates that decreased expression of slit diaphragm protein, nephrin, correlates with a loss of glomerular filter integrity. Additionally, we demonstrate that defects induced by proteins of glomerular basement membrane lead to an insidious plasma protein leak, whereas the defects induced by proteins in the glomerular epithelial slit diaphragms lead to a precipitous plasma protein leak.

Bioelectronic sniffer device for trimethylamine vapor using flavin containing monooxygenase

A bioelectronic sniffer device for trimethylamine (TMA) in the gas phase fish-odor substance was constructed using a flavin-containing monooxygenase 3 (FMO3, one of xeno-biotic metabolizing enzymes) and a reaction unit with both gas and liquid cells separated by a porous poly(tetrafluoroethylene) diaphragm membrane (pore size: 30-60 /spl mu/m, thickness: 0.20 mm). A substrate regeneration cycle was applied to the FMO3 immobilized device in order to amplify the output signal by coupling the monooxygenase with a reducing reagent system of ascorbic acid (ASA) in phosphate buffer. The sniffer device with 10.0 mmol/l AsA could be used to measure TMA vapor from 0.52 to 105 ppm; this covers the maximum permissible concentration in the work place (5.0 ppm of time weighted average concentration) and the sensing level-5 of smell in humans (3.0 ppm). Since the application of the substrate regeneration cycle was possibly successful, it improved the sensitivity of the FMO3 immobilized device. The sniffer device possessed high selectivity for TMA being attributable to the FMO3 substrate specificity, continuous measurability, and good reproducibility in the repeatedly measurements (coefficient of variation = 2.41%, n=10).

アンモニア計測用バイオノーズに関する研究

A gas-phase biosensor (bio-nose) for ammonia was fabricated by incorporating an enzyme electrode with flavin-containing monooxygenase into a reaction unit with both liquid- and gas-phase cells separated a porous diaphragm membrane. The bio-nose was calibrated against ammonia vapors from 3.72 to 366ppm.

Emodin-induced muscle contraction of mouse diaphragm and the involvement of Ca2+ influx and Ca2+ release from sarcoplasmic reticulum.

1. The effects on skeletal muscle of emodin, an anthraquinone, were studied in the mouse isolated diaphragm and sarcoplasmic reticulum (SR) membrane vesicles. 2. Emodin dose-dependently caused muscle contracture, simultaneously depressing twitch amplitude. Neither tubocurarine nor tetrodotoxin blocked the contraction suggesting that it was caused myogenically. 3. The contraction induced by emodin persisted in a Ca2+ free medium with a slight reduction in the maximal force of contraction. The contraction induced by emodin in the Ca2+ free medium was completely blocked when the internal Ca2+ pool of the muscle was depleted by ryanodine. These data suggest that the contraction caused by emodin is due to the release of Ca2+ from the intracellular ryanodine-sensitive pool. 4. In contrast to the effect seen in the Ca2+ free medium, emodin induced a small but consisted contraction in the ryanodine-treated muscle in Krebs medium. The contraction was blocked in the presence of dithiothreitol and was partially blocked by nifedipine, suggesting that oxidation of a sulphhydryl group on the external site of dihydropyridine receptor is involved. 5. Emodin dose-dependently increased Ca2+ release from actively loaded SR vesicles and this effect was blocked by ruthenium red, a specific Ca2+ release channel blocker, and the thiol reducing agent, DTT, suggesting that emodin induced Ca2+ release through oxidation of the critical SH of the ryanodine receptor. 6. [3H]-ryanodine binding was dose-dependently potentiated by emodin in a biphasic manner. The degree of potentiation of ryanodine binding by emodin increased dose-dependently at concentrations up to 10 microM but decreased at higher concentrations of 10-100 microM. 7. These data suggest that muscle contraction induced by emodin is due to Ca2+ release from the SR of skeletal muscle, as a result of oxidation of the ryanodine receptor and influx of extracellular Ca2+ through voltage-dependent Ca2+ channels of the plasma membrane.

Effect of age and caloric restriction on insulin receptor binding and glucose transporter levels in aging rats.

We report on the effect of age and chronic caloric restriction (CR) on insulin binding and glucose transporter content in both diaphragm and heart muscle membrane of young (11 months), mid-age (17 months), and old (29 month) ad libitum fed and CR Brown-Norway rats. The control animals received rat chow ad lib and CR animals were allowed 60% of ad libitum food. The CR regimen was initiated at four months of age and the animals were maintained on their respective diets until necropsy. There was no effect of age on insulin binding for either ad libitum or CR animals at each age evaluated. Caloric restriction significantly lowered insulin levels at each age studied when compared to the ad libitum-fed rats. However, CR animals were noted to have increased insulin binding (p < 0.001) compared to ad libitum-fed animals at each age for diaphragm muscle. For the heart, there appeared to be a decreased binding, particularly at higher insulin concentrations, in CR-fed animals. There was no net change in Glut-1 or Glut-4 levels for heart muscle membrane, or Glut-4 levels for diaphragm muscle membrane between ad libitum or CR animals. This data indicates that caloric restriction may have tissue-specific effects for insulin receptor binding, and that the improved insulin sensitivity in CR states is not a result of altered glucose transporter protein content.

Test facilities for diaphragm filter presses, on-site under field conditions

Practical experience is the best foundation for achieving optimum performance and efficiency in liquid/solids separation with diaphragm filter presses. The state-of-the-art in engineering technology is ultimately measured by the results achieved, and can only be developed further for specific applications in an empirical manner by continuing analysis and constant comparisons with actual practical results on-site. This is why Lenser has developed a production-size mobile filtration testing facility, capable of filtration testing with chamber and diaphragm (membrane) filter elements under field conditions. We discuss the company's various testing facilities

Mathematical problems in modeling artificial heart

In this paper we discuss some problems arising in mathematical modeling of artificial hearts. The hydrodynamics of blood flow in an artificial heart chamber is governed by the Navier‐Stokes equation, coupled with an equation of hyperbolic type subject to moving boundary conditions. The flow is induced by the motion of a diaphragm (membrane) inside the heart chamber attached to a part of the boundary and driven by a compressor (pusher plate). On one side of the diaphragm is the blood and on the other side is the compressor fluid. For a complete mathematical model it is necessary to write the equation of motion of the diaphragm and all the dynamic couplings that exist between its position, velocity and the blood flow in the heart chamber. This gives rise to a system of coupled nonlinear partial differential equations; the Navier‐Stokes equation being of parabolic type and the equation for the membrane being of hyperbolic type. The system is completed by introducing all the necessary static and dynamic boundary conditions. The ultimate objective is to control the flow pattern so as to minimize hemolysis (damage to red blood cells) by optimal choice of geometry, and by optimal control of the membrane for a given geometry. The other clinical problems, such as compatibility of the material used in the construction of the heart chamber, and the membrane, are not considered in this paper. Also the dynamics of the valve is not considered here, though it is also an important element in the overall design of an artificial heart. We hope to model the valve dynamics in later paper.

Inferences on passive diaphragm mechanics from gross anatomy

The diaphragm is a relatively thin curved structure that is categorized in mechanics as a membrane. Tension in the membrane is given by the product of muscle thickness and stress parallel to the fiber bundles. If all muscle fibers were cylindrical and extended from origin to insertion, the ratio of thickness near the chest wall (CW) to thickness near the central tendon (CT) would vary inversely with the ratio of CW to CT perimeters. In freshly excised diaphragms of 36 mongrel dogs, the ratios of the perimeters (CT/CW) in the right and left costal diaphragm were 0.63 +/- 0.04 and 0.62 +/- 0.04, respectively. The means of the ratio of thickness near CW to that near CT in the right and left costal regions were 0.96 +/- 0.07 and 0.95 +/- 0.05, respectively, consistent with a nearly constant relationship between costal diaphragm membrane tension and muscle stress in the direction of the fibers. In the crural diaphragm, the average ratio of the perimeters of the insertions on CT to CW was 1.16 +/- 0.10. The average ratio of thickness of crural CW to CT was 1.25 +/- 0.11. The discrepancy between the perimeter ratio and thickness ratio in the costal diaphragm is incompatible with the muscle consisting of uniform fibers extending from CW to CT. Our data suggest that muscle fibers are either in series with a smaller number along the smaller perimeter or that they terminate by tapering within the muscle bundle. Both arrangements are consistent with previous anatomic studies (Gordon et al. J. Morphol. 201: 131-143, 1989). Having a nonuniform number of fibers mechanically in series is compatible with uniform stress in the fibers if the membrane is sufficiently curved as in a domed structure.

Flow-through and flow-by porous electrodes of nickel foam Part IV: experimental electrode potential distributions in the flow-through and in the flow-by configurations

Experimental distributions of the solution potential in flow-through and flow-by porous electrodes of nickel foam operating in limiting current conditions are presented. These are in good agreement with the corresponding theoretical distributions. In the case of a flow-by configuration used in a two-compartment cell, the experiments confirm the validity of the models, presented in Part III, which take into account the presence of a separator (ceramic porous diaphragm or ion exchange membrane).

Cutaneous metastasis of a colonic carcinoma in a dog

ABSTRACTAn entire seven‐year‐old Afghan bitch was referred with a two month history of pruritic, erythematous and ulcerated lesions involving the skin of the ventral abdomen, caudal mammae, inguinal region and the inner thighs. Other clinical signs included pyrexia, mild dyspnoea, mammary hypertrophy and lactation. A skin biopsy confirmed an anaplastic carcinoma. At necropsy, the neoplasm was located in the colon, urinary bladder, liver, peritoneal wall, diaphragm, parietal pleura and mediastinal membranes, including the pericardial sac attachment. The colon was considered to be the primary site.