Ischemic preconditioning is not additive to preservation with hypothermia or crystalloid cardioplegia in the globally ischemic rat heart

The aim of this study was to evaluate the additive protective efficiency of ischemic preconditioning when used in combination with conventional clinically relevant cardioprotective methods of hypothermia or hypothermic cardioplegia during sustained global ischemia.Isolated rat hearts were aorta-perfused with Krebs-Henseleit buffer and were divided into six groups (n = 10 each). Group I: Ischemia at 34°C for 60 min; Group PC+I: preconditioned (PC) ischemia at 34°C, 2 episodes of 5 min ischemia and 10 min reperfusion at 34°C followed by I; Group HI: hypothermic ischemia at 10°C for 60 min; Group PC+HI: preconditioned (PC) hypothermic ischemia, 2 episodes of 5 min ischemia and 10 min reperfusion at 34°C followed by HI; Group CPL+HI: single dose of 'Plegisol' cardioplegia followed by HI; Group PC+CPL+HI: preconditioned hypothermic cardioplegia, followed by CPL+HI. At the end of 60 min ischemia, all the hearts were reperfused at 34°C for 30 min when post-ischemic recovery in left ventricular contractile function and coronary vascular dynamics was computed and compared.There was a significant depression in the post-ischemic recovery of developed pressure (P_max), positive derivative of pressure (+dp/dt), negative derivative of pressure (-dp/dt) and heterometric autoregulation (HA) of contractile force in all the groups, with no major differences between the groups. Left ventricular end-diastolic pressure (LVEDP) was significantly elevated after I at 34°C. Preconditioning (PC+I) prevented the rise in the LVEDP and this was accompanied by a significant reduction in the release of purine metabolises in the coronary effluents, particularly adenosine, during the immediate reperfusion period. Hypothermia (HI) provided essentially the same level of metabolic and mechanical preservation as offered by PC+I. Combination of hypothermia with preconditioning (PC+HI) or cardioplegia (PC+CPL+HI), did not further enhance the preservation. Post-ischemic recovery in the regional contractile function (segment shortening, %SS) followed nearly identical pattern to global (P_max) recovery. Post-ischemic recovery in coronary flow (CF) was significantly reduced and coronary vascular resistance (CVR) was significantly increased in all the groups. Myogenic autoregulation (transient and sustained) was generally enhanced indicating increased vascular reactivity. Preconditioning did not alter the time-course of these changes.Preconditioned ischemia (34°C) preserved left ventricular diastolic functions and prevented the contracture development after sustained ischemia reperfusion at 34°C. This protective effect of preconditioning was possibly mediated by the reduction in the breakdown of purine metabolises. Hypothermia alone or in combination with crystalloid cardioplegia prevented the irreversibility of the ischemic injury but produced contractile and vascular stunning which was not improved by ischemic preconditioning. The results of this study indicate that preconditioning when combined with hypothermia or hypothermic cardioplegia offered no significant additional protection.     

Optimization of citric acid production by Aspergillus niger using two downgraded Algerian date varieties

In the present work, the GHARS and the MECH DEGLA downgraded date varieties were used in a fermentation medium in order to produce citric acid by the Aspergillus niger. The biochemical characteristics of the dates were investigated, along with the chemical and physical characteristics of the solutions of both samples. The analyzed parameters included the moisture and sugar content, the ash residual, the pH values, and the electrical conductivity. The effect of the following fermentation parameters was studied: initial pH, temperature, incubation period, and methanol. For the GHARS and MECH DEGLA date varieties respectively, the ash residual measured at 1.90% and 2.47%. For each date variety, the moisture and total sugars were measured at 11.59% and 85%, for the GHARS, and 12.82% and 80.47% for the MECH DEGLA. Citric acid production using either of the two varieties of dates showed a high yield in a short time.The obtained results showed that the highest production of citric acid by both medium of dates was achieved at the initial pH value of 3.0, temperature 30 °C, and an incubation period of 8 days. Also, the maximum amount of citric acid was produced when both mediums contained 4% of methanol. Both varieties of dates showed a good yield for the citric acid and can be used as a culture medium since they are economic and ensure good growth for the Aspergillus niger.     

Arp2/3 complex is important for filopodia formation, growth cone motility, and neuritogenesis in neuronal cells

A role of Arp2/3 complex in lamellipodia is well established, whereas its roles in filopodia formation remain obscure. We addressed this question in neuronal cells, in which motility is heavily based on filopodia, and we found that Arp2/3 complex is involved in generation of both lamellipodia and filopodia in growth cones, and in neuritogenesis, the processes thought to occur largely in Arp2/3 complex-independent manner. Depletion of Arp2/3 complex in primary neurons and neuroblastoma cells by small interfering RNA significantly decreased the F-actin contents and inhibited lamellipodial protrusion and retrograde flow in growth cones, but also initiation and dynamics of filopodia. Using electron microscopy, immunochemistry, and gene expression, we demonstrated the presence of the Arp2/3 complex-dependent dendritic network of actin filaments in growth cones, and we showed that individual actin filaments in filopodia originated at Arp2/3 complex-dependent branch points in lamellipodia, thus providing a mechanistic explanation of Arp2/3 complex functions during filopodia formation. Additionally, Arp2/3 complex depletion led to formation of multiple neurites, erratic pattern of neurite extension, and excessive formation of stress fibers and focal adhesions. Consistent with this phenotype, RhoA activity was increased in Arp2/3 complex-depleted cells, indicating that besides nucleating actin filaments, Arp2/3 complex may influence cell motility by altering Rho GTPase signaling.     

Human palatine tonsil: a new potential tissue source of multipotent mesenchymal progenitor cells

Introduction  

Mesenchymal progenitor cells (MPCs) are multipotent progenitor cells in adult tissues, for example, bone marrow (BM). Current challenges of clinical application of BM-derived MPCs include donor site morbidity and pain as well as low cell yields associated with an age-related decrease in cell number and differentiation potential, underscoring the need to identify alternative sources of MPCs. Recently, MPC sources have diversified; examples include adipose, placenta, umbilicus, trabecular bone, cartilage, and synovial tissue. In the present work, we report the presence of MPCs in human tonsillar tissue.     

Regioselectivity in the glycosylation of 5-(3-chlorobenzo[b]thien-2-yl)-4H-1,2,4-triazole-3-thiol

The glycosylation of 5-(3-chlorobenzo[b]thien-2-yl)-4H-1,2,4-triazole-3-thiol (1) and its 3-benzylsulfanyl and 3-methylsulfanyl derivatives with different glycosyl halides 2-4 has been studied in presence of base. The S-glycosides 5-7 were obtained in the presence of triethylamine, whereas the respective S,N⁴-bis(glycosyl) derivatives 8-10 were synthesized in the presence of potassium carbonate; the S,N²-bis(glycosyl) isomer 11 could also be isolated in the case of the galactosyl analog. Similarly, after protecting 1 as 3-benzyl(methyl)sulfanyl derivatives 12 or 13, the N⁴-glycosyl analogs 14-19 as well as minor amounts of S,N²-bis(galactosyl) isomers 20 and 21 were formed. The theoretical calculations using AM1 semiempirical methods agreed with the experimental results. Microwave irradiation (MWI) led to higher yields in much less time than the conventional methods, and no change in regioselectivity has been noticed.     

Zinc,Manganese, Calcium,Copper, and Cadmium Level in Scalp Hair Samples of Schizophrenic Patients

The purpose of the study was to determine the concentration of trace elements present in scalp hair sample of schizophrenic patients and to find out the relationship between trace elements level and nutritional status or socioeconomic factors. The study was conducted among 30 schizophrenic male patients and 30 healthy male volunteers. Patients were recruited from Bangabandhu Sheikh Mujib Medical University by random sampling. Hair trace element concentrations were determined by flame atomic absorption spectroscopy and analyzed by independent t test, Pearson’s correlation analysis, regression analysis, and analysis of variance (ANOVA). Mn, Zn, Ca, Cu, and Cd concentrations of schizophrenic patients were 3.8 ± 2.31 μg/gm, 171.6 ± 59.04 μg/gm, 396.23 ± 157.83 μg/gm, 15.40 ± 5.68 μg/gm, and 1.14 ± 0.89 μg/gm of hair sample, while those of control subjects were 4.4 ± 2.32 μg/gm, 199.16 ± 27.85 μg/gm, 620.9 ± 181.55 μg/gm, 12.23 ± 4.56 μg/gm, and 0.47 ± 0.32 μg/gm of hair sample, respectively. The hair concentration of Zn and Ca decreased significantly (p = 0.024; p = 0.000, respectively) and the concentration of Cu and Cd increased significantly (p = 0.021; p = 0.000, respectively) in schizophrenic patients while the concentration of Mn (p = 0.321) remain unchanged. Socioeconomic data reveals that most of the patients were poor, middle-aged and divorced. Mean body mass indices (BMIs) of the control group (22.26 ± 1.91 kg/m²) and the patient group (20.42 ± 3.16 kg/m²) were within the normal range (18.5−25.0 kg/m²). Pearson’s correlation analysis suggested that only Ca concentration of patients had a significant positive correlation with the BMI (r = 0.597; p = 0.000) which was further justified from the regression analysis (R ² = 44%; t = 3.59; p = 0.002) and one-way ANOVA test (F = 3.62; p = 0.015). A significant decrease in the hair concentration of Zn and Ca as well as a significant increase in the hair concentration of Cu and Cd in schizophrenic patients than that of its control group was observed which may provide prognostic tool for the diagnosis and treatment of this disease. However, further work with larger population is suggested to examine the exact correlation between trace element level and the degree of disorder.