A polymerized bovine hemoglobin oxygen carrier preserves regional myocardial function and reduces infarct size after acute myocardial ischemia

The purpose of this study was to test if HBOC-201, a hemoglobin-based oxygen-carrying solution, can decrease infarct size (or Inf) during acute, severe myocardial ischemia and reperfusion. To test the impact of HBOC-201 on infarct size, ischemia was produced in 18 dogs by coronary stenosis to achieve 80-95% flow reduction for 195 min along with pacing 10% above the spontaneous heart rate, followed by 180 min of reperfusion. Animals were randomized to intravenous infusion of HBOC-201 (1 g/kg) (n=6), normal saline (NS) (n=6), or phenylephrine (Phe) (n=6, as a control for the increased blood pressure seen with HBOC-201), given 15 min after the start of ischemia. Amount of infarct was quantified as the ratio between area at risk (AAR) and Inf after Evans blue and 2,3,5-triphenyltetrazolium chloride staining. Hearts were divided into five layers from base (layer A) to apex (layer E) and photographed for digital image analysis of AAR and Inf. Regional myocardial function (RMF) was also measured after 60 min of ischemia and 15 min of reperfusion. Inf/AAR was significantly reduced after HBOC-201 therapy (4.4+/-2.2%) vs. NS (26.0+/-3.6%) and Phe (25.7+/-4.1%) (both, P<0.05). RMF after reperfusion was restored to 92% of baseline with HBOC-201 compared with 11% of baseline after NS (P<0.05) and 49% after Phe (P=not significant). HBOC-201 administration after induction of severe myocardial ischemia by acute coronary stenosis reduces infarct size and improves myocardial viability.     

Alloxan reduces amplitude of ventricular myocyte shortening and intracellular Ca2+ without altering L-type Ca2+ current, sarcoplasmic reticulum Ca2+ content or myofilament sensitivity to Ca2+ in Wistar rats

Alloxan is widely used to induce diabetes mellitus in experimental animals. Recent studies have provided evidence that alloxan has direct actions on cardiac muscle contraction. The aim of this study was to further investigate the mechanisms underlying the effects of alloxan on ventricular myocyte shortening and intracellular Ca²⁺ transport. Amplitude of myocyte shortening was reduced in a dose-dependent manner as the concentration of alloxan was increased in the range 10^?7–10^?4 M. Amplitude of shortening was reduced (56.8 ± 6.6%, n = 27) by 10^?6 M alloxan and was partially reversed during a 10 min washout. Amplitude of the Ca²⁺ transient was also reduced (79.7 ± 2.9%, n = 29) by 10^?6 M alloxan. Caffeine-evoked sarcoplasmic reticulum Ca²⁺ release, fractional release of Ca²⁺, assessed by comparing the amplitude of electrically evoked with that of caffeine-evoked Ca²⁺ transients, and fura-2-cell length trajectory during the late stages of relaxation of myocyte twitch contraction were not significantly altered by alloxan. The amplitude of L-type Ca²⁺ current was not altered by alloxan. Alterations in sarcoplasmic reticulum Ca²⁺ transport, myofilament sensitivity to Ca²⁺, and L-type Ca²⁺ current do not appear to underlie the negative inotropic effects of alloxan.     

Skin closure with dye-enhanced laser welding and fibrinogen

The topical application of wavelength-specific dye and fibrinogen has been used to enhance laser closure of vascular anastomoses. We compared the closure of skin incisions by two different dye-enhanced, fibrinogen-based laser welding systems [argon laser (power density 4.78 W/cm2) with fluorescein isothiocyanate dye (n = 32) and diode laser (power density 9.55 W/cm2) with indocyanine green dye (n = 32)] with closure by interrupted 5-0 nylon suture (n = 64) and examined tensile strength, hydroxyproline production, histology, and cosmesis. Two 3-cm full-thickness incisions were made on the shaved backs of 64 rats. One incision was closed with suture, whereas the other, after treatment with the appropriate dye, was welded with either argon- or diode-lasered fibrinogen. At postoperative days 5, 10, 15, and 28, the closure sites were harvested and sectioned for analysis. Initially, wounds closed with argon-lasered fibrinogen showed less inflammatory response, greater collagen production (34.61 +/- 0.74 mg/gm), and greater mean peak stress at rupture (64.85 lbs/in2) than those closed with suture (16.42 +/- 3.20 mg/gm, 26.68 lbs/in2) (p less than 0.05). By 15 days, both argon and diode laser closures are superior in strength and collagen production to suture closure (p less than 0.05). At 28 days, diode laser closures (1315.60 lbs/in2) are stronger than suture closures (998.09 lbs/in2), whereas both are stronger than argon laser closures (813.16 lbs/in2) (p less than 0.05). Cosmetically, argon-welded wounds consistently appeared finer and lacked cross-hatched suture scars.(ABSTRACT TRUNCATED AT 250 WORDS)     

Candidate gene case-control and functional study shows macrophage inhibitory factor (MIF) polymorphism is associated with cutaneous leishmaniasis

American tegumentary leishmaniasis (ATL) is an infectious disease caused mostly by Leishmania (Viannia) braziliensis in Southeast Brazil. The clinical manifestations are vast, ranging from asymptomatic to severe mucosal leishmaniasis (ML). It has been suggested that variation of the pathogen does not fully explain the response spectrum and the variability of clinical manifestations. Previous data have shown that host genetics also play a role in disease outcome. Herein, we have tested the association of TNF, IL10, IL12 and MIF single nucleotide polymorphisms (SNPs) using a case-control study design including 110 cutaneous leishmaniasis (CL) patients and 682 healthy subjects. The genotype–phenotype correlation was also assessed using leishmania antigens to stimulate peripheral blood mononuclear cells obtained from cured CL patients. Results demonstrated that the MIF ?173C allele is associated with leishmaniasis outcome and also with lower levels of MIF in culture supernatants. Also, the TNF ?308AA genotype was statistically increased among leishmaniasis patients. The results showed here suggest that the lower levels of MIF produced by MIF ?173C carriers could influence the host–Leishmania interaction, favoring infection and disease progression. On the other hand, high TNF levels can contribute to tissue damage, consequently leading to skin lesions.     

Mercury distribution in two commercial fish species (Pimelodus maculatus and Calophysus macropterus) - Case study of river Acre (Acre state,Brazilian Amazon)

Abstract

Total mercury (Hg) concentrations were assessed during July 2017 in two commercial fish species Pimelodus maculatus and Calophysus macropterus from two locations of Acre river (Acre State, Brazilian Amazon) - Iñapari (undeveloped areas) and Assis Brazil (urban areas). The current study aimed to assess: (i) Hg spatial variations; (ii) the assimilation efficiencies in different tissues and (iii) the ecological quality of these ecosystems based on tissue Hg concentrations. Both species showed significantly (p?<?.05) different Hg concentrations between tissues. Hg concentrations were significantly higher than those previously reported for these Amazon regions. Hg concentrations in Assis Brazil were significantly higher (p?<?.05) than in Iñapari, indicating an anthropogenic influence. Bioaccumulation factors indicated that kidney and liver are the main Hg retention tissues. Considering European and Brazilian mercury guidelines in foodstuff, Iñapari and Assis Brazil are “Unpolluted” during July 2017, although hepatic Hg concentrations in C. macropterus from Assis Brazil showed evidences of anthropogenic contamination.     

Spatio-temporal and intra-specific variations in the physiological and biochemical condition of the invasive bivalve Corbicula fluminea

Hydrobiologia - Corbicula fluminea is a known aquatic invasive species responsible for several ecological and economic impacts. In Portugal, it is found in all major watersheds, although to varying...