Anterior Segment Surgeries Under Topical Fresh Frozen Plasma Treatment in Ligneous Conjunctivitis.

PURPOSE: To evaluate the efficacy of topical fresh frozen plasma (FFP) therapy on clinical symptoms, findings, and prognosis after anterior segment surgeries in patients with ligneous conjunctivitis (LC). METHODS: Retrospective case note review. RESULTS: Eleven eyes of 7 cases whose remission was not achieved after medical treatment such as topical corticosteroids, cyclosporine A, and heparin were included in the study. The median age of admission was 19 (1-49) years, median duration of FFP treatment was 48 (15-79) months, median follow-up period was 62 (16-114) months, and median age at symptom onset was 12 (4-252) months. Diagnosis was made according to clinical presentations, plasminogen activities, and response to treatment. Topical FFP that was prepared in our clinic was used in all cases. Surgeries (membrane excision, eyelid surgery, deep anterior lamellar keratoplasty, and cataract surgery) were performed after at least 1 month of FFP treatment. Prosthetic contact lens was applied to one eye. During the follow-up period, recurrences requiring membrane excision and side effects from topical FFP were not observed. CONCLUSIONS: LC is a rare membranous conjunctivitis that proceeds with remissions and recurrences. When it was shown that the etiology of LC is plasminogen deficiency, FFP became the only treatment option targeting the etiology. In this study, we observed that the topical FFP is an effective treatment method that prevents recurrence and ensures regression of membranes and safer anterior segment surgeries in LC.

Bioactive effects of nonthermal argon-oxygen plasma on inorganic bovine bone surface.

As a commonly used bone substitute material in the clinic, inorganic bovine bone has the characteristics of osteoconduction but not osteoinduction. This study aimed to treat inorganic bovine bone using nonthermal argon-oxygen plasma (NTAOP) to obtain greater bioreactivity for enhancing adhesion, proliferation and differentiation of mouse preosteoblast MC3T3-E1 cells. In this study, inorganic bovine bone was activated by NTAOP, and the surface characteristics were analyzed. MC3T3-E1 cells were then seeded onto the surface of inorganic bovine bone. Cell morphology, proliferation and osteogenic differentiation were examined. There was no obvious change in the surface morphology of specimens between the two groups. Regarding the elemental composition of the material, the amount of surface carbon was reduced, whereas oxygen, phosphorus and calcium levels were increased in the NTAOP group. Further studies showed that the NTAOP groups performed better than their untreated counterparts in terms of supporting cell proliferation and differentiation. Inorganic bovine bone treated with NTAOP can promote preosteoblast adhesion, proliferation and differentiation.

Autologous plasma and its supporting role in fat graft survival: A relevant vector to counteract resorption in lipofilling.

Fat grafting has become a widespread technique for different reconstructive and esthetic purposes. However, the disadvantage of fat grafting is the unpredictable resorption rate that often necessitates repetitive procedures, which in turn may have an impact on the morbidity. During the immediate, post-graft, ischemic period, cells survive due to the process of plasmatic imbibition. This biological phenomenon precedes the ingrowth of neo-capillaries that eventually nourish the graft and help establish a long-term homeostatic equilibrium. Both partners, the graft and the recipient bed, contribute to the revascularization process. Hypothetically, enrichment of the recipient site with autologous plasma could have a beneficial role to enhance fat graft survival. We investigated whether plasma supported the viability of the lipoaspirate (LA) material. Plasma was isolated from blood samples collected from eight patients during the elective lipofilling procedures. An in vitro study assessed the viability of LA cells using plasma as a culture medium compared to the traditional culture media. In vitro analysis confirmed sustained viability of LA cells compared to the standard media and control media during 7 consecutive days. The behavior of the fat grafts in plasma showed similarities with those incubated in the traditional culture media. In future, these findings could be translated to a clinical setting. Plasma is the only autologous substrate available in large quantities in the human body. The addition of the supporting agents, such as plasma, could contribute to a better graft survival with more stable clinical outcomes in the long term. The rationale behind the technique is based on the phenomenon of plasmatic imbibition and the reasoning that the extracellular matrix plays a pivotal role in cellular survival.

Eculizumab en recién nacido con síndrome hemolitico urémico atípico: a propósito de un caso / Eculizumab for atypical hemolytic uremic syndrome in newborn: a case report

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Plasma and Plasma Protein Product Transfusion: A Canadian Blood Services Centre for Innovation Symposium.

Plasma obtained via whole blood donation processing or via apheresis technology can either be transfused directly to patients or pooled and fractionated into plasma protein products that are concentrates of 1 or more purified plasma protein. The evidence base supporting clinical efficacy in most of the indications for which plasma is transfused is weak, whereas high-quality evidence supports the efficacy of plasma protein products in at least some of the clinical settings in which they are used. Transfusable plasma utilization remains composed in part of applications that fall outside of clinical practice guidelines. Plasma contains all of the soluble coagulation factors and is frequently transfused in efforts to restore or reinforce patient hemostasis. The biochemical complexities of coagulation have in recent years been rationalized in newer cell-based models that supplement the cascade hypothesis. Efforts to normalize widely used clinical hemostasis screening test values by plasma transfusion are thought to be misplaced, but superior rapid tests have been slow to emerge. The advent of non-vitamin K-dependent oral anticoagulants has brought new challenges to clinical laboratories in plasma testing and to clinicians needing to reverse non-vitamin K-dependent oral anticoagulants urgently. Current plasma-related controversies include prophylactic plasma transfusion before invasive procedures, plasma vs prothrombin complex concentrates for urgent warfarin reversal, and the utility of increased ratios of plasma to red blood cell units transfused in massive transfusion protocols. The first recombinant plasma protein products to reach the clinic were recombinant hemophilia treatment products, and these donor-free equivalents to factors VIII and IX are now being supplemented with novel products whose circulatory half-lives have been increased by chemical modification or genetic fusion. Achieving optimal plasma utilization is an ongoing challenge in the interconnected worlds of transfusable plasma, plasma protein products, and recombinant and engineered replacements.

Trifolium pallidum and Trifolium scabrum extracts in the protection of human plasma components.

Clovers (genus: Trifolium) have been used in traditional medicine by many cultures, but the biological activity of the most of these plants still remains unknown. The aim of our in vitro study was to assess the antioxidative action of phenolic extracts from aerial parts of Trifolium scabrum and Trifolium pallidum in human blood plasma, exposed to oxidative stress. In the present study we also demonstrate, for the first time the effects of the tested extracts on coagulative properties and fibrinolytic activity of blood plasma. The protective properties of the examined extracts (0.5-50 µg/ml) against peroxynitrite-induced oxidative stress were estimated by the measurements of 3-nitrotyrosine, thiol groups and the thiobarbituric acid-reactive substances levels. The extracts considerably prevented the oxidative and nitrative damage to plasma proteins. Even the lowest doses of the Trifolium extracts (0.5 µg/ml) were able to markedly reduce 3-nitrotyrosine formation (by about 50%) and to increase the level of -SH groups (by about 30%), in comparison to the plasma exposed to ONOO(-) in the absence of the extracts. The protective action of all the used concentrations of the Trifolium extracts in the prevention of lipid peroxidation was also found. The tested extracts influenced neither the coagulative properties nor fibrinolytic activity of plasma. Moreover, the extracts were able to significantly reduce the inhibitory effect of ONOO(-) on fibrinolytic activity of plasma (assessed with the use of a chromogenic substrate for plasmin).

Spray-dried porcine plasma influences intestinal barrier function, inflammation, and diarrhea in weaned pigs.

The objective of this study was to evaluate the effects of dietary inclusion levels of spray-dried porcine plasma (SDPP) on postweaning (PW) intestinal barrier function, mucosal inflammation, and clinical indices of gut health in pigs. Ex vivo Ussing chamber studies were conducted to measure Ileal and colonic barrier function in terms of transepithelial electrical resistance and paracellular flux of (3)H-mannitol and (14)C-inulin. Intestinal inflammation was assessed by histological analysis and mucosal levels of proinflammatory cytokines. Dietary inclusion of 2.5 and 5% SDPP reduced colonic paracellular permeability of (14)C-inulin compared with controls (0% SDPP) on d 7 PW. Both 2.5 and 5% dietary SDPP reduced ileal (3)H-mannitol and (14)C-inulin permeability on d 14 PW. The 5% SDPP diet reduced colonic short-circuit current, an index of net electrogenic ion transport, and fecal scores when measured on d 7 and 14 PW compared with the control and 2.5% SDPP groups (P < 0.05). Histological analysis revealed fewer lamina propria cells in ileum and colon from pigs fed diets containing 2.5 and 5% SDPP on d 7 and 14 PW. Levels of the proinflammatory cytokine TNFα were reduced in the colon but not ileum from pigs fed the 5% SDPP on d 7 and 14 PW compared with controls (P < 0.05). IFNγ levels were lower than in controls in both of the SDPP-fed groups in the ileum and colon on d 7 but not on d 14 PW. Overall, this study demonstrated that dietary inclusion of SDPP had beneficial effects on intestinal barrier function, inflammation, and diarrhea in weaned pigs.

Medicinal herb research: serum pharmacological method and plasma pharmacological method.

Serum pharmacological method has generally been used in herb studies. However, preparation of test serum for ex vivo experiment is an intricate process: besides pretreatment (heat or chemicals), it involves the proteolytic cascades of coagulation along with fibrinolysis, complement and kinin systems, as well as platelet and leukocyte activation resulting in release reactions. These processes deviate serum sample components away from the original in vivo state, and possibly also have effects on the absorbed herbal components and their downstream effectors in blood. The conclusions drawn from serum pharmacological method are at least partially uncertain in its validity. These processes can be avoided by anticoagulation. Compared to those of the serum, constituents of plasma are better reflectors of the in vivo physiological/pathological state and medicinal herb-induced changes. Therefore, we have advocated the adoption of plasma pharmacological method in ex vivo experiments of herb studies. Recent studies including our work demonstrated that the constituents and biological activities are partially different between absorbed medicinal herbs in plasma and serum. This review summarizes the experimental evidence supporting the feasibility of plasma pharmacological method and discusses the reasons and facts that flaw the serum pharmacological method. But serum pharmacological method can be used if anticoagulants interfere with experiments. It should be emphasized that the domination between plasma and serum pharmacological methods is different depending on the usage. Indeed, the pros and cons of both methods as well as the appropriate choices of coagulants in different ex vivo experimental settings remain to be further elucidated.

Protein phosphorylation stoichiometry by simultaneous ICP-QMS determination of phosphorus and sulfur oxide ions: a multivariate optimization of plasma operating conditions.

Molecular mass spectrometry (MS) analysis of protein phosphorylation is partially limited by the molecular specie specificity of the analytical responses that might impair both qualitative and quantitative performances. Elemental MS, such as inductively coupled plasma mass spectrometry (ICP-MS) can overcome these drawbacks; in fact, analytical performance is theoretically independent of the molecular structure of a target analyte naturally containing the elements of interest. Nevertheless, isobaric interferences derived from sample matrix and laboratory environment can hinder the quantitative determination of both phosphorus (P) and sulfur (S) as (31)P(+) and (32)S(+) by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) under standard plasma conditions. These interferences may be overcome by quantifying P and S as oxide ions (31)P(16)O(+) and (32)S(16)O(+), respectively. In this study, we present a systematic investigation on the effect of plasma instrumental conditions on the oxide ion responses by a design of experiment approach for the simultaneous ICP-QMS determination of P and S ((31)P(16)O(+) and (32)S(16)O(+), respectively) in protein samples without the use of dynamic reaction, collision reaction cells or pre-addition of oxygen as reactant gas in the torch. The proposed method was evaluated in terms of limit of detection, limit of quantification, linearity, repeatability, and trueness. Moreover, detection and quantification capabilities of the optimized method were compared to the standard plasma mode for determination of (31)P(+) and (34)S(+). Spectral and non-spectral interferences affecting the quantification of (31)P(+), (31)P(16)O(+) and (32)S(16)O(+) were also studied. The suitability of inorganic elemental standards for P and S quantification in proteins was assessed. The method was applied to quantify the phosphorylation stoichiometry of commercially available caseins (bovine beta-casein, native and dephosphorylated alpha-casein) and results were confirmed by Matrix Assisted Laser Desorption Ionization Time of Flight MS analysis. We demonstrate that ICP-QMS, by quantifying P and S as oxide ions, was able to accurately calculate the degree of phosphorylation of beta-casein and alpha-casein and to detect specific partial enzymatic dephosphorylation. The collected results might lead to further development of ICP-QMS interfaces optimized for protein phosphorylation studies and for proteomics investigations.

Oxidative impairment of plasma and skeletal muscle sarcoplasmic reticulum in rats with adjuvant arthritis - effects of pyridoindole antioxidants.

OBJECTIVES: To study possible oxidation of proteins and lipids in plasma and sarcoplasmic reticulum (SR) from skeletal muscles and to assess the effects of pyridoindole antioxidants in rats with adjuvant arthritis (AA) and to analyze modulation of Ca-ATPase activity from SR (SERCA). METHODS: SR was isolated by ultracentrifugation, protein carbonyls in plasma and SR were determined by ELISA. Lipid peroxidation was analyzed by TBARS determination and by mass spectrometry. ATPase activity of SERCA was measured by NADH-coupled enzyme assay. Tryptophan fluorescence was used to analyze conformational alterations. RESULTS: Increase of protein carbonyls and lipid peroxidation was observed in plasma of rats with adjuvant arthritis. Pyridoindole antioxidant stobadine and its methylated derivative SMe1 decreased protein carbonyl formation in plasma, effect of stobadine was significant. Lipid peroxidation of plasma was without any effect of pyridoindole derivatives. Neither protein oxidation nor lipid peroxidation was identified in SR from AA rats. SERCA activity from AA rats increased significantly, stobadine and SMe1 diminished enzyme activity. Ratio of tryptophan fluorescence intensity in SR of AA rats increased and was not influenced by antioxidants. CONCLUSION: Plasma proteins and lipids were oxidatively injured in rats with AA; antioxidants exerted protection only with respect to proteins. In SR, SERCA activity was altered, apparently induced by its conformational changes, as supported by study of tryptophan fluorescence. Stobadine and SMe1 induced a decrease of SERCA activity, elevated in AA rats, but they did not affect conformational changes associated with tryptophan fluorescence.

In vitro proliferation and differentiation of human mesenchymal stem cells cultured in autologous plasma derived from bone marrow.

Expansion of human mesenchymal stem cells (hMSCs) in medium supplemented with fetal bovine serum (FBS) has a potential risk of transmitting viral and prion diseases and causing immunological rejection. The aim of our present study was to find a substitute for the traditional FBS in culture of hMSCs to facilitate the clinical application of hMSCs. We used autologous plasma derived from bone marrow (APM) as a substitute for FBS and found that, when cultured with APM, the cell surface markers and the proportion of hMSCs in the G(0)/G(1) phase and the S+G(2)/M phase resembled those cultured with FBS. However, there were fewer early apoptotic cells in APM-supplemented medium than in FBS (p < 0.01). APM resulted in much greater thymidine incorporation than FBS (p < 0.001). There were significantly more alkaline phosphatase (ALP)-positive fibroblast colony-forming units (CFU-Fs) covering larger areas in APM than in FBS (p < 0.01). Also, APM induced greater ALP activity, more mineralized nodules, and greater expression of osteogenic genes than did FBS. In addition, when cultured in adipogenic medium, there were fewer oil-red O-positive cells and lower expression of adipogenic gene with APM than with FBS. In conclusion, expansion of hMSCs in APM-supplemented medium instead of traditional FBS is more advantageous. It could promote cell proliferation, enhance osteogenic differentiation, and suppress adipogenic differentiation of hMSCs and is therefore a safer and more effective substitute for FBS in clinical cytotherapy processes.

Platelet-rich plasma: a review of biology and applications in plastic surgery.

Healing of hard and soft tissue is mediated by a complex array of intracellular and extracellular events that are regulated by signaling proteins, a process that is, at present, incompletely understood. What is certain, however, is that platelets play a prominent if not deciding role. Controlled animal studies of soft and hard tissues have suggested that the application of autogenous platelet-rich plasma can enhance wound healing. The clinical use of platelet-rich plasma for a wide variety of applications has been reported; however, many reports are anecdotal and few include controls to definitively determine the role of platelet-rich plasma. The authors describe platelet biology and its role in wound healing; the preparation, characterization, and use of platelet-rich plasma; and those applications in plastic surgery for which it may be useful.

Effects of spray-dried porcine plasma and plant extracts on intestinal morphology and on leukocyte cell subsets of weaned pigs.

We evaluated the effects of a 6% spray-dried porcine plasma (SDPP) and a plant extracts mixture (XT; 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin) on the productive performance, intestinal morphology, and leukocyte cell subsets of early-weaned pigs compared with a control group. Morphometry of the jejunum, ileum, and colon, and immune cell analysis of blood, ileocolic lymph node (LN), and ileal Peyer's patches were done in 24 weaned pigs (20 +/- 2 d) at 19 or 21 d postweaning. Although SDPP and XT treatments did not increase ADG or ADFI, SDPP improved the G:F ratio (P = 0.024) compared with the control group. Dietary SDPP reduced the percentages of blood monocytes (P = 0.006) and macrophages in ileal Peyer's patches and LN (P = 0.04), of B lymphocytes (P = 0.04) and gammadelta+ T cells in LN (P = 0.009), and of intraepithelial lymphocytes (P = 0.026) as well as the density of lamina propria cells in the colon (P < 0.01). Dietary XT reduced intraepithelial lymphocyte numbers in jejunum (P = 0.034) and the percentages of blood cytotoxic cells (P = 0.07) and B lymphocytes in LN (P = 0.03); however, XT increased blood monocytes (P = 0.038) and the density of lamina propria lymphocytes in the colon (P = 0.003). These results indicate that dietary SDPP and plant extracts can affect intestinal morphology and immune cell subsets of gut tissues and blood in weaned pigs. Furthermore, the effects of SDPP suggest lower activation of the immune system of the piglets.

Mechanism of vasopeptidase inhibitor-induced plasma extravasation: comparison of omapatrilat and the novel neutral endopeptidase 24.11/angiotensin-converting enzyme inhibitor GW796406.

We describe N-[(2S)-2-(mercaptomethyl)-3-methylbutanoyl]-4-(1H-pyrazol-1-yl)-L-phenylalanine (GW796406), a vasopeptidase inhibitor (VPI) that possessed approximately 3-fold selectivity for neutral endopeptidase 24.11 (NEP) versus angiotensin-converting enzyme (ACE) in in vitro assays using rat and human enzymes. In the same assays, omapatrilat, the most extensively studied VPI, displayed approximately 3-fold selectivity for ACE. The in vivo ACE and NEP inhibition profile and the liability of the compounds to increase plasma extravasation were compared at two (low and high) therapeutically equivalent intravenous doses in the rat. At the low dose, both agents inhibited ACE activity by approximately 85%. Consistent with their in vitro ACE/NEP selectivity, omapatrilat produced 49% inhibition, whereas GW796406 produced >95% inhibition of NEP. Neither compound increased plasma extravasation. When the low dose was administered to rats pretreated with the NEP inhibitor ecadotril to normalize NEP background to <5% of control, only omapatrilat significantly increased plasma extravasation. At the high dose, omapatrilat and GW796406 produced profound, nonselective inhibition of ACE (>90%) and NEP (>95%), and they significantly increased plasma extravasation. The activity of the agents as inhibitors of dipeptidylpeptidase IV (DPP IV) and aminopeptidase P (APP) was also investigated. Neither compound inhibited DPP IV. Interestingly, omapatrilat, but not GW796406, was a relatively potent inhibitor of APP (IC50 = 260 nM). We investigated whether APP inhibition increased the plasma extravasation liability of GW796406. The low dose of GW796406 administered with apstatin, an APP inhibitor, did not increase plasma extravasation. This finding inferred that APP inhibition is not involved in plasma extravasation in the rat and that APP inhibition does not explain the increased plasma extravasation produced by omapatrilat in NEP-inhibited rats.

Measurement of adhesion of human platelets in plasma to protein surfaces in microplates.

INTRODUCTION: Platelet adhesion is an initial, crucial and complex event for inhibiting blood loss upon vascular injury. Activation and adhesion of platelets also play a fundamental role in the development of thrombosis. A combination of exposed extracellular matrix proteins in the vascular wall and release of activating compounds from the participating cells activate the platelets. New potent anti-platelet agents are in progress but there is a shortage of methods that measure the concerted action of adhesive surfaces and soluble compounds upon platelet adhesion in vitro. The aim of this work was to develop a method to measure adhesion of platelets in plasma with standard laboratory equipment. METHODS: Platelet-rich plasma from healthy humans was used in studies to optimise the conditions of the present assay. Different proteins were coated in microplate wells and various soluble platelet activators and inhibitors were added to establish the ability of the current method to detect increased as well as decreased platelet adhesion. The amount of platelet adhesion was measured by the reaction between p-nitrophenyl phosphate and the intracellular enzyme acid phosphatase. RESULTS: Adhesion of platelets in plasma to microplate wells coated with albumin, collagen, fibrinogen and activated plasma showed significant surface dependency. The known soluble platelet activators adenosine diphosphate, adrenaline and ristocetin enhanced the levels of adhesion. Available anti-platelet agents such as prostacyclin, forskolin, acetylsalicylic acid and RGD containing peptides caused dose-dependent inhibition of platelet adhesion. DISCUSSION: This report describes a further development of a previously described method and offers the advantage to use platelets in plasma to measure platelet adhesion to protein surfaces. The assay is simple and flexible and is suitable in basic research for screening and characterisation of platelet adhesion responsiveness.

Modulation of adenine nucleotide concentrations in human plasma by erythrocytes and endothelial cells.

The regulation of plasma concentrations of adenine nucleotides is unsettled. We tested the possibility of extracellular adenosine triphosphate (ATP) production from adenosine diphosphate (ADP) at physiological low concentrations by erythrocytes and endothelial cells. Filtered erythrocytes and human umbilical vein endothelial cells (HUVEC) were incubated for 15 to 120 s with ADP (10 microM), supplemented with 3H-ADP (2.85 nM) or 14C-ADP (54.6 nM). Enzymatic conversion of ADP to ATP was detected by recovery of the radioactive label in the ATP fraction. ATP was measured in the supernatant using high performance liquid chromatography (HPLC) separation, scintillation techniques, and luminometry. Using etheno (epsilon)-labeled ADP (10 microM), the extracellular localization of the conversion was further corroborated. Following ADP application in plasma, no radioactivity was detected in the ATP fraction. However, in erythrocyte suspensions, 12.9% and 9.7% of the label were recovered in the ATP fraction after application of 3H- and 14C-ADP, respectively. Between 15 and 120 s after 3H-ADP application, the 3H-ATP fraction was found to be stable at around 10%. For the range of ADP concentrations studied (10-40 microM), no saturation of ATP production was achieved. The extracellular localization of conversion was supported by the recovery of the epsilon -label in the epsilon -ATP fraction. In contrast, on HUVEC a conversion of epsilon -ADP to epsilon -ATP was not observed. In conclusion, on erythrocytes there is rapid enzymatic conversion of extracellular ADP to ATP which may play a significant role in adjusting adenine nucleotide concentrations in human plasma. In endothelial cells, extracellular conversion of ADP to ATP is of quantitatively minor importance, if it contributes at all.

[Usefulness of the Biofeedback Diacontrol module in the automatic programming of plasmatic conductivity and ionic mass transfer]. / Utilidad del módulo de "Biofeedback" Diacontrol en la programación automática de la conductividad plasmática y la transferencia de masa iónica.

Programmed variable sodium in the dialysate can improve hypotension during hemodialysis but may also alter sodium balance and thus resulting in a increase of water intake and weight gain between dialysis sessions. The aim of this study was to evaluate the changes on plasma volume (PV), Ionic Mass Transfer (IMT) and plasma conductivity (PC) with two different hemodialysis techniques. We studied 10 patients during a four-period protocol (one week each: PF1-DC1-DC2PF2): 120 dialysis sessions. During periods PF1 and PF2, the dialysis procedure was as usual, with exponential decrease of dialysate conductivity (DC) profile (15.7 mS/cm at start, 14.4 mS/cm at middle and 13.8 mS/cm at the end of the session) and UF profile (1.7 1/h at start and 0.1 1/h at the end). During periods DC1 and DC2, DC was automatically determined by a biofeedback modulae (Diacontrol) in order to reach a plasma water conductivity fixed at 14 mS/cm. All hemodialysis parameters were the same for the four periods: duration, blood and dialysate flow rates, dialysis membrane. A lower reduction of PV was evident on PF1 and PF2 (104 +/- 3.26% and -4.36 +/- 2.7%) compared with DC 1 and DC2 (-6.53 +/- 3.31% and -6.67 +/- 3.12%) (p < 0.001). No significant differences were seen in systolic, mean and diastolic blood pressure pre-HD or post-HD, UF, and weight gain, between the four periods. Hypotensive episodes were seen in 33.3% of PF1, 20% of DC1, 23.3% of DC2 and 26.6% of PF2 sessions (NS). PF1 and PF2 periods resulted in a significantly higher 30', mid and post-dialysis PC as compared to DC1 and DC2 periods (p < 0.001). The mean difference between the actual value and the prescribed value of PC at the end of the session was -0.01 +/- 0.07 mS/cm (n: 60). There was a negative correlation between the mean DC during session and the PC at 30' of session. IMT was 420.73 +/- 126.9 mEq in PF1, 311.96 +/- 161.75 in DC1, 278.34 +/- 153.14 in DC2 and 417.66 +/- 152.17 in PF2 (p > 0.001 PF1 and PF2 vs. DC1 and DC2). Diacontrol determines automatically an individualized DC profile for each patient, and accurately reaches the prescribed PC target. By reaching both the dry weight and PC settings, the water and sodium pool is maintained lower in the hemodialysis session using a biofeedback module. Clinical tolerance was similar in the two different dialysis procedures.

Erythrocyte survival is promoted by plasma and suppressed by a Bak-derived BH3 peptide that interacts with membrane-associated Bcl-X(L).

Erythrocytes have a defined lifespan in vivo, and the signals that maintain their survival in circulation or trigger their death are unknown. Here, we investigated the control of erythrocyte survival and death in an in vitro culture system where erythrocytes survived for 10 days in serum-free medium in the presence or absence of bovine serum. Death of the cells in culture was correlated with increased exposure of phosphatidylserine and increased levels of intracellular calcium. Cell death could be suppressed by supplementing the medium with human plasma or serum, resulting in a doubling of the lifespan to 20 days. Freshly isolated erythrocytes and cultured erythrocytes were both found to express Bcl-X(L) and, to a lesser extent, Bak in membrane protein extracts. Treatment of the cells with a Bak-derived BH3 peptide fused to the internalization sequence of the antennapedia protein, which has previously been shown to enter cells by diffusion and antagonize Bcl-X(L), resulted in substantial cell death in erythrocyte cultures. BH3-induced death was accompanied by an immediate increase in accumulation of intracellular calcium and could be suppressed by plasma, but not by the caspase inhibitor zVAD. A BH3 peptide mutated at amino acid 78 of full-length Bak required for heterodimerization with Bcl-X(L) had no effect on cell viability or calcium levels. We conclude that the BH3 peptide accelerates erythrocyte death through antagonization of Bcl-X(L). The data suggest that erythrocyte survival is promoted by survival factors in plasma and by membrane-associated Bcl-X(L.)

Does edema formation occur in the rabbit brain exposed to head-down tilt?

Earlier studies showed that exposure to microgravity caused cephalad fluid shift, increased capillary pressure in the head, and produced facial edema and nasal congestion. In the present study, edema formation in the brain was investigated in rabbits exposed to simulated microgravity, head-down tilt (HDT), by measuring water content and histological examinations. Water content in the brain tissues of rabbits exposed to 2 and 8 days of HDT did not increase significantly compared with that of control animals. Neither vital staining using Evans blue nor immunohistochemical examination demonstrated extravasation of plasma constituents in the brain tissues of the HDT rabbits. Although marked congestion was noted in the brain, hematoxylin and eosin staining did not show edematous changes, such as distension of the perivascular and pericellular spaces and vacuolar appearance, in the tissues obtained from HDT rabbits. Transmission electron microscopy revealed that tight junctions of the capillary endothelium were intact in the HDT rabbits. These results suggest that either HDT up to 8 days does not cause brain edema in rabbits or it induces only a slight brain edema which is hard to be demonstrated by measurement of water content or histological examinations.