Principles of optical oximetry in extracorporeal circulation systems]

The paper outlines the optical properties of blood as a random unhomogenous scattering and absorbing medium and presents the basic characteristics of single erythrocyte diffusers. It also shows how the above dependencies are used in particular oximeters. The first world's laser oximeter designed by the authors is described.     

Evidence of porcine and human endothelium activation by cancer-associated carbohydrates expressed on glycoproteins and tumour cells

It is well established that after metastatic cancer cells escape the primary tumour and enter the circulation, their interactions with microvascular endothelium of a target organ constitute an essential rate-limiting step in haematogenous cancer metastasis. However, the physiological and biochemical processes supporting neoplastic cell arrest and retention in the microcirculation are still poorly understood. In this study, we present experimental evidence that microvascular endothelium of metastasis-prone tissues undergoes activation in response to desialylated cancer-associated carbohydrate structures such as Thomsen–Friedenreich (TF) antigen (Galβ1–3GalNAc) expressed on circulating glycoproteins and neoplastic cells. The metastasis-associated endothelium activation, manifested by marked increase in endothelial cell surface galectin-3 expression, causes gradual decrease in cancer cell velocities (from 72 × 10²± 33 × 10²μm s⁻¹ to 7.6 × 10²± 1.9 × 10²μm s⁻¹, mean ± s.d. ) accompanied by a corresponding increase in the percentage of rolling cells (from 3.3%± 1.2% to 24.3%± 3.6%, mean ± s.d. ), and results in human breast and prostate carcinoma cell arrest and retention in the microvasculature. This process, which could be of high importance in haematogenous cancer metastasis, was inhibited efficiently by an anti-TF antigen function-blocking antibody. Carbohydrate-mediated endothelial activation could be a process of physiological significance as it probably occurs in the interactions between a variety of circulating constituents and the vessel wall.     

Effects of combining inducible nitric oxide synthase inhibitor and radical scavenger during porcine bacteremia

Complex interactions of nitric oxide and other free radicals have been implicated in the pathogenesis of sepsis and organ dysfunction. We hypothesized that simultaneous inducible nitric oxide synthase inhibition (L-N6-[1-iminoethyl]-lysine [L-NIL]) and neutralization of superoxide (O2-) (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl [Tempol]) would protect from detrimental consequences of long-term, volume-resuscitated, hyperdynamic porcine bacteremia. In this prospective, randomized, controlled experimental study, 16 anesthetized, mechanically ventilated and instrumented pigs were exposed to 24 h of continuous infusion of live Pseudomonas aeruginosa. After 12 h of hyperdynamic sepsis, animals were randomized to receive either vehicle (control, n = 8) or combination of L-NIL and Tempol (n = 8). Systemic and hepatosplanchnic hemodynamics, oxygen exchange, metabolism, ileal mucosal microcirculation and tonometry, oxidative stress and coagulation parameters were assessed before, 12, 18, and 24 h of P. aeruginosa infusion. Combined treatment inhibited sepsis-induced increase in plasma nitrate/nitrite, 8-isoprostane, and thiobarbituric acid reactive species concentrations, prevented hypotension, and reversed hyperdynamic circulation. Despite lower intestinal macrocirculation, combined regimen attenuated the otherwise progressive deterioration in ileal mucosal microcirculation and prevented mucosal acidosis. Treatment substantially attenuated mesenteric and hepatic venous acidosis, preserved sepsis-induced impairment of hepatosplanchnic redox state, and prevented the development of renal dysfunction. Finally, coinfusion of L-NIL and Tempol largely attenuated the sepsis-induced rise in plasma von Willebrand factor and thrombin-antithrombin complexes. Thus, hemodynamic, microcirculatory, metabolic, renal, and coagulation data indicate that combining inducible inhibition with cell permeable O2(-) radical scavenger afforded significant protection in porcine sepsis, thus suggesting an important interactive role of O2(-) and nitric oxide in mediating organ dysfunction.     

EPR Identification of Zr(III) Complexes Formed upon Interaction of (2-PhInd)2ZrCl2 and rac-Me2Si(1-Ind)2ZrCl2 with MAO and MMAO

Reactions of 1 and 2 with MAO and MMAO were monitored by EPR. It was found that MMAO is a stronger reducing agent than MAO. 1 is more prone to reduction than 2 . The reduction of Zr^IV to Zr^III seems to be the essential pathway of some zirconocene catalysts' deactivation. Zr^III species with the following proposed structures can be identified in the 1 /MMAO system: (2-PhInd)₂Zr^III(ⁱBu), (2-PhInd)₂Zr^III(µ-Cl)₂AlⁱBu₂, (2-PhInd)₂Zr^III(µ-Cl)(ⁱBu)AlⁱBu₂, and [(2-PhInd)₂Zr^III]⁺[Me-MAO]⁻. The degree of reduction of Zr^IV species determined by EPR in the catalytic system 2 /MMAO can be masked by the formation of diamagnetic Zr^III/Zr^III dimers. Addition of monomers to the 2 /MAO system promotes reduction ot the zirconium species.

     

Spatial mapping of protein abundances in the mouse brain by voxelation integrated with high-throughput liquid chromatography-mass spectrometry

Temporally and spatially resolved mapping of protein abundance patterns within the mammalian brain is of significant interest for understanding brain function and molecular etiologies of neurodegenerative diseases; however, such imaging efforts have been greatly challenged by complexity of the proteome, throughput and sensitivity of applied analytical methodologies, and accurate quantitation of protein abundances across the brain. Here, we describe a methodology for comprehensive spatial proteome mapping that addresses these challenges by employing voxelation integrated with automated microscale sample processing, high-throughput liquid chromatography (LC) system coupled with high-resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometer, and a "universal" stable isotope labeled reference sample approach for robust quantitation. We applied this methodology as a proof-of-concept trial for the analysis of protein distribution within a single coronal slice of a C57BL/6J mouse brain. For relative quantitation of the protein abundances across the slice, an 18O-isotopically labeled reference sample, derived from a whole control coronal slice from another mouse, was spiked into each voxel sample, and stable isotopic intensity ratios were used to obtain measures of relative protein abundances. In total, we generated maps of protein abundance patterns for 1028 proteins. The significant agreement of the protein distributions with previously reported data supports the validity of this methodology, which opens new opportunities for studying the spatial brain proteome and its dynamics during the course of disease progression and other important biological and associated health aspects in a discovery-driven fashion.     

Assessment of potential hazards during the process of house building in Estonia

The aim of this study was to evaluate new working conditions in the construction industry in Estonia. Three construction sites were investigated: a dwelling house at the stage of renovation, a warehouse at the stage of excavation and preparation work, and a hotel, where we examined the working conditions of the finishers. Microclimate: air temperature, relative humidity and air velocity were determined at every workplace. Full-shift personal exposure measurements of dust and gas exposure were performed among 97 construction workers in breathing zone air. The concentration of lead in the air was analysed by AAS. Vapours of benzene, styrene and toluene concentrations were determined by gas chromatography. The noise level was measured with the help of the sound-level meter at every workplace. All microclimatic indices were sometimes below or above exposure standards for indoor work. High levels of airborne dust and increased concentrations of lead were observed during repair work. Low concentrations of organic solvents in the air were determined when using paints and some synthetic substances. The noise level exceeded the permitted limit when an excavator and powerful electric appliances were used. A questionnaire determined the prevalence of subjectively experienced musculoskeletal strain in 30% of workers. The working conditions in the construction industry in Estonia are approaching European level. However, it is necessary to improve working conditions permanently by the use of new harmless materials, personal protective equipment, and through influencing worker health by permanent education and medical watch. We consider that questionnaires are very important in the control of the work environment, in subjective health assessments, and as a source of useful proposals to improve working conditions.     

Efficiency of acidemia correction on intermittent versus continuous hemodialysis in acute methanol poisoning

Context: Acidemia is a marker of prognosis in methanol poisoning, as well as compounding formate-induced cytotoxicity. Prompt correction of acidemia is a key treatment of methanol toxicity and methods to optimize this are poorly defined.

Objective: We studied the efficiency of acidemia correction by intermittent hemodialysis (IHD) and continuous renal replacement therapy (CRRT) in a mass outbreak of methanol poisoning.

Methods: The study was designed as observational cohort study. The mean time for an increase of 1?mmol/L HCO₃^–, 0.01 unit arterial blood pH, and the total time for correction of HCO₃^– were determined in IHD- and CRRT-treated patients.

Results: Data were obtained from 18 patients treated with IHD and 13 patients treated with CRRT. At baseline, CRRT group was more acidemic than IHD group (mean arterial pH 6.79?±?0.10 versus 7.05?±?0.10; p?=?0.001). No association was found between the rate of acidemia correction and age, weight, serum methanol, lactate, formate, and glucose on admission. The time to HCO₃^– correction correlated with arterial blood pH (r=??0.511; p?=?0.003) and creatinine (r?=?0.415; p?=?0.020). There was association between the time to HCO₃^– correction and dialysate/effluent and blood flow rates (r=??0.738; p?r=??0.602; p?The mean time for HCO₃^– to increase by 1?mmol/L was 12?±?2?min for IHD versus 34?±?8?min for CRRT (p?p?=?0.024). The mean increase in HCO₃^– was 5.67?±?0.90?mmol/L/h for IHD versus 2.17?±?0.74?mmol/L/h for CRRT (p?Conclusions: Our study supports the superiority of IHD over CRRT in terms of the rate of acidemia correction.     

Locations of the beta1 transmembrane helices in the BK potassium channel

BK channels are composed of α-subunits, which form a voltage- and Ca²⁺-gated potassium channel, and of modulatory β-subunits. The β1-subunit is expressed in smooth muscle, where it renders the BK channel sensitive to [Ca²⁺]_i in a voltage range near the smooth-muscle resting potential and slows activation and deactivation. BK channel acts thereby as a damped feedback regulator of voltage-dependent Ca²⁺ channels and of smooth muscle tone. We explored the contacts between α and β1 by determining the extent of endogenous disulfide bond formation between cysteines substituted just extracellular to the two β1 transmembrane (TM) helices, TM1 and TM2, and to the seven α TM helices, consisting of S1–S6, conserved in all voltage-dependent potassium channels, and the unique S0 helix, which we previously concluded was partly surrounded by S1–S4. We now find that the extracellular ends of β1 TM2 and α S0 are in contact and that β1 TM1 is close to both S1 and S2. The extracellular ends of TM1 and TM2 are not close to S3–S6. In almost all cases, cross-linking of TM2 to S0 or of TM1 to S1 or S2 shifted the conductance–voltage curves toward more positive potentials, slowed activation, and speeded deactivation, and in general favored the closed state. TM1 and TM2 are in position to contribute, in concert with the extracellular loop and the intracellular N- and C-terminal tails of β1, to the modulation of BK channel function.     

Cytocidal macrophages in symbiosis with CD4 and CD8 T cells cause acute diabetes following checkpoint blockade of PD-1 in NOD mice

Autoimmune diabetes is one of the complications resulting from checkpoint blockade immunotherapy in cancer patients, yet the underlying mechanisms for such an adverse effect are not well understood. Leveraging the diabetes-susceptible nonobese diabetic (NOD) mouse model, we phenocopy the diabetes progression induced by programmed death 1 (PD-1)/PD-L1 blockade and identify a cascade of highly interdependent cellular interactions involving diabetogenic CD4 and CD8 T cells and macrophages. We demonstrate that exhausted CD8 T cells are the major cells that respond to PD-1 blockade producing high levels of IFN-γ. Most importantly, the activated T cells lead to the recruitment of monocyte-derived macrophages that become highly activated when responding to IFN-γ. These macrophages acquire cytocidal activity against β-cells via nitric oxide and induce autoimmune diabetes. Collectively, the data in this study reveal a critical role of macrophages in the PD-1 blockade-induced diabetogenesis, providing new insights for the understanding of checkpoint blockade immunotherapy in cancer and infectious diseases.

Two of the most widely studied proteins that regulate T cell activation are cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1). Inhibiting them can unleash regulatory controls of T cell activation, allowing the T cells to display their full functional potential. CTLA-4 and PD-1 are extensively studied in the cancer field, where their inhibitors—monoclonal antibodies—are used to treat cancer patients. Despite achieving success clinically, the checkpoint blockade immunotherapy can result in immune-related adverse events that frequently include endocrine autoimmune diseases (1), among them type 1 diabetes (T1D) (2–4). A recent comprehensive review summarized the clinical features of T1D induced by the immune checkpoint inhibition (4).To better understand how PD-1 is regulating T1D, we examine here the nonobese diabetic (NOD) mouse model for changes in various cellular components following PD-1 blockade. PD-1 is synthesized de novo in activated T cells mediated by T cell receptor (TCR) signaling (5–7). Whereas PD-1 expression is rapidly up-regulated after antigen stimulation of naïve T cells, sustained TCR stimulation results in substantially higher expression of PD-1 and the establishment of T cell exhaustion in the examples of chronic viral infection and cancers (8–13). NOD mice with a gene knockout of PD-1 or treated with PD-1 blocking antibody develop accelerated autoimmune diabetes shown in a number of studies (14–21). Both autoreactive CD4 and CD8 T cells can respond to PD-1/PD-L1 blockade and contribute to the acute diabetes development (17–19). Central in this process is PD-L1 (the ligand of PD-1) expressed by the islet parenchymal cells (20, 21), which limits the T cell function in the islets and protects against autoimmune diabetes.In this report we examine changes in various cellular components following PD-1 blockade by single-cell RNA sequencing (scRNA-seq) and identify a previously unexplored islet macrophage population derived from monocytes with high proinflammatory activity. In the islets of anti–PD-1–treated mice, the infiltration by monocyte-derived macrophage (MoMac) was under the influence of CD4 and particularly CD8 T cells. The CD8 T cells largely comprised the precursor exhausted T (T_PEX) cells that were activated and differentiated to produce abundant IFN-γ in response to PD-1 blockade, which in turn activated the infiltrated MoMac to promote diabetes progression. The anti–PD-1 induced development of acute diabetes was reduced by restricting the infiltration and function of such MoMac in islets. Our study establishes that the myeloid cell compartment is an indispensable component of PD-1 regulation in autoimmune diabetes. Our study provides a cellular target, the MoMac, that may minimize the adverse effects of checkpoint blockade immunotherapy.