The reciprocal influence of the liver and blood stages of the malaria parasite’s life cycle

While the liver and blood stages of the Plasmodium life cycle are commonly regarded as two separate fields of malaria research, several studies have pointed towards the existence of a bidirectional cross-talk, where one stage of mammalian infection may impact the establishment and progression of the other. Despite the constraints in experimentally addressing concurrent liver and blood stage Plasmodium infections, animal models and clinical studies have unveiled a plethora of molecular interactions between the two. Here, we review the current knowledge on the reciprocal influence of hepatic and erythrocytic infection by malaria parasites, and discuss its impacts on immunity, pathology and vaccination against this deadly disease.     

Functional and metabolic assessment of the blood cell’s response to exposure to local vibration

Physiological characteristics of blood cells in workers exposed to long-term local vibration were studied. The total cell peroxidase activity, the level of the phagocytic response, neutrophil alkaline phosphatase and acid phosphatase activity levels, and glycogen content in neutrophils and lymphocytes were measured. Changes associated with a decrease in the functional metabolic parameters, depending on the duration of contact with vibrating tools and the severity of clinical symptoms, were detected. The detected differences in changes in cell response may reflect the specific features of the mechanisms of adaptive regulation.     

Proteomics of blood and derived products: what’s next?

Proteomics has changed the way proteins are analyzed in living systems. This approach has been applied to blood products and protein profiling has evolved in parallel with the development of techniques. The identification of proteins belonging to red blood cell, platelets or plasma was achieved at the end of the last century. Then, the questions on the applications emerged. Hence, several studies have focused on problems related to blood banking and products, such as the aging of blood products, identification of biomarkers, related diseases and the protein–protein interactions. More recently, a mass spectrometry-based proteomics approach to quality control has been applied in order to offer solutions and improve the quality of blood products. The current challenge we face is developing a closer relationship between transfusion medicine and proteomics. In this article, these issues will be approached by focusing first on the proteome identification of blood products and then on the applications and future developments within the field of proteomics and blood products.     

Novel insights into the development and maintenance of the blood–brain barrier

The blood–brain barrier (BBB) is essential for maintaining homeostasis within the central nervous system (CNS) and is a prerequisite for proper neuronal function. The BBB is localized to microvascular endothelial cells that strictly control the passage of metabolites into and out of the CNS. Complex and continuous tight junctions and lack of fenestrae combined with low pinocytotic activity make the BBB endothelium a tight barrier for water soluble moleucles. In combination with its expression of specific enzymes and transport molecules, the BBB endothelium is unique and distinguishable from all other endothelial cells in the body. During embryonic development, the CNS is vascularized by angiogenic sprouting from vascular networks originating outside of the CNS in a precise spatio-temporal manner. The particular barrier characteristics of BBB endothelial cells are induced during CNS angiogenesis by cross-talk with cellular and acellular elements within the developing CNS. In this review, we summarize the currently known cellular and molecular mechanisms mediating brain angiogenesis and introduce more recently discovered CNS-specific pathways (Wnt/β?catenin, Norrin/Frizzled4 and hedgehog) and molecules (GPR124) that are crucial in BBB differentiation and maturation. Finally, based on observations that BBB dysfunction is associated with many human diseases such as multiple sclerosis, stroke and brain tumors, we discuss recent insights into the molecular mechanisms involved in maintaining barrier characteristics in the mature BBB endothelium.     

Small mammal diversity of a poorly known and threatened Amazon region,the Tapajós Area of Endemism

Biodiversity and Conservation - The Amazon region is a mosaic of distinct areas of endemism (AoE), each with its evolutionary relationships and biotic assemblages. Among them, the Tapajós AoE...     

Influence of the human blood serum on contractility and β-adrenoreactivity of the isolated human myocardium

Influence of adrenaline (10⁻⁹ to 10⁻⁴ g/ml) on the contraction amplitude caused by electrostimuli (1Hz, 5 ms, 25–30 V) and inotropic and adrenomodulation activities of blood serum of nonpregnant women (at dilutions of 1 : 10 000, 1 : 1000, 1 : 500, 1 : 100, 1 : 50, 1 : 10, and 1 : 5) have been studied. The study has been carried out on isolated myocardium strips of the right atrial auricle that were taken from 43 patients with ischemic illness of the heart and 9 patients with valvular heart diseases of various etiologies upon venous cannula insertion during an aortocoronary bypass. Direct dependence of the contraction amplitude on the cardiac output according to Teicholz has been found. This meant that strips of the right atrial auricle reflected the contractility of the left ventricle myocardium. Adrenaline has been shown to dose-dependently increase the amplitude of evoked contractions in the concentration interval from 10⁻⁷ to 10⁻⁶ g/ml and had no influence from 10⁻⁹ to 10⁻⁸ g/ml (dissociation constant, 2 × 10⁻⁷ g/ml), which proved a decrease in the β-adrenoreceptor’s (β-AR) activation. Blood serum in a dilution range from 1 : 10 000 to 1 : 50 had no effect on the contraction amplitude, but an enhanced effect has been found in a dilution range from 1 : 10 and 1 : 5. The presence of the endogenous activator of myocytes contractility (EAMC) has explained this enhanced effect. The β-adrenomodulation activity of blood serum has been explained by the presence of the endogenous sensitizer of β-AR (ESBAR) and the endogenous blocker of β-AR (EBBAR). The ESBAR activity of blood serum (dilutions: 1 : 1000, 1 : 500, 1 : 100, and 1 : 50) has been found in experiments with a subthreshold adrenaline concentration (10⁻⁸ g/ml). ESBAR (dilutions: 1 : 50 and 1 : 10) and EBBAR (dilution 1 : 500) activities of blood serum have been found in experiments with the maximum effective concentration of adrenaline (10⁻⁶ g/ml). Therefore, blood serum endogenous modulators of β-adrenergic reactivity, ESBAR and EBBAR, can modulate the activation of β-AR of human cardiomyocytes. These prove the prospects of the ESBAR analogue application in cardiology.     

Results of the oxygen Fick method in a closed blood circulation model including “total arteriovenous diffusive shunt of oxygen”

It is considered that arteriovenous diffusive shunts of oxygen may cause inaccuracy of the oxygen Fick method as where is the pulmonary oxygen uptake, is the cardiac output, and CaO₂ and CvO₂ are the arterial and venous oxygen contents, respectively. A simple circulation model, including the whole circulation with nine well-mixed compartments (C1, ... C9), is constructed: the is assigned as constant as 6000 ml min⁻¹; the blood portions of 60 ml move at an interval of 600 ms. C1 and C2 compartments, each having 60 ml volume, represent the blood of pulmonary microcirculation, C3 represents the arterial blood with a volume of 1500 ml, C4, ..., C8, each also having a volume of 60 ml, represent the blood of peripheral microcirculation, whereas C9 represents the venous blood with a volume of 3000 ml. The pulmonary oxygen uptake , related to C1 and C2, the oxygen release , related to C4,...,C8, as well as a “total arteriovenous diffusive shunt of oxygen” , from the arterial blood (C3) to the venous blood (C9), are calculated simultaneously. The alveolar gas has a constant oxygen partial pressure, and the pulmonary diffusion capacity is also constant; similar to modeling the pulmonry, oxygen diffusion, constant partial oxygen pressures for all peripheral tissues as well as constant diffusion capacities for all peripheral oxygen diffusion are also assigned. The diffusion capacities for the (between C3 and C9) are arbitrarily assigned. The Fick method gives incorrect results depending on the total arteriovenous diffusive shunt of oxygen . But the mechanism determining the magnitude of remains unclear.     

Isograft and xenograft of the subcommissural organ into the lateral ventricle of the rat and the formation of Reissner’s fiber

The subcommissural organ (SCO) secretes glycoproteins into the cerebrospinal fluid (CSF) that aggregate and form Reissner's fiber (RF). The factors involved in this aggregation are not known. One factor may be the hydrodynamics of the CSF when flowing through the aqueduct. This hypothesis was tested by isografting rat SCO and xenografting bovine SCO into the lateral ventricle of rats. Xenografts were either fresh bovine SCO or explants cultured for 30 days before transplantation. The grafts were investigated by electron microscopy and immunocytochemistry using antibodies against RF glycoproteins, serotonin and the glucose transporter I. Maximal time of transplantation was 43 days for isografts and 14 days for xenografts. The isografts were not reinnervated but were revascularized; they secreted into the ventricle RF glycoproteins that became progressively packed into pre-RF and RF structures identical to those formed by the SCO in situ. RF was confined to the host ventricle and at its distal end the constituent proteins disassembled. Xenografts were neither reinnervated nor revascularized and secreted into the host ventricle a material that never formed an RF. These findings indicate that the CSF factor responsible for the formation of RF is species specific, and that this process does not depend on the hydrodynamics of the CSF. The blood vessels revascularizing the isografted SCO acquired the characteristics of the vessels irrigating the SCO in situ, namely, a tight endothelium displaying glucose transporter I, and a perivascular space containing long-spacing collagen, thus indicating that basal release of glycoproteins may also occur in the grafted SCO.     

The fertility of women Poland in the period of trasformation of the political and economics system (the 80’s and 90’s)

Wielkopolska (western Poland) is a region, with good reason, called the main food base of Poland. All indices of agricultural production have always been there (since 19th century) much higher than elsewhere in the country (Ratajczak 1977/1978, Buszko 1984, Gorzelak 1989, Czyzewski et al. 1992; table 1). Such a situation had a beneficial effect on the amount of the income generated by a family of Wielkopolska and, thus, decided on its better financial status. Additionally, rural inhabitants of this region have always been characterised by a more advantageous educational structure in comparison with people of other Polish villages. Generally, it is easy to detect the relationship between the life standard, the level of education and family planning. The aim of this paper is to assess fertility of women from villages of Wielkopolska in the period of transformation of the political and economic system in Poland.     

Merleau-Ponty’s Concept of Nature and the Ontology of Flesh

The essay attempts to delineate how Maurice Merleau-Ponty’s phenomenology of perception can be applied to theories of sign processes, and how it reworks the framework of the phenomenalist conception of communication. His later philosophy involved a reformulation of subjectivity and a resolution of the subject/object dualism. My claim is that this non-reductionist theory of perception reveals a different view of nature as we experience it in an expressive and meaningful interaction. The perspective that another living being has and communicates entails a form of depth, the invisible dimension of the visible or audible. These two aspects of perception and dialogue are intertwined in a dialectic of presence and absence, so that sense arises in the perceptual field rather than in subjectivity. This, I argue, is the most fundamental result of his theory. The origination of meaning in the workings of the chiasm of visible and invisible in perception opens up an objective sense of intersubjective nature. The essay also deals with the role of the phenomenological reduction; a suspension of beliefs and existence claims in experience. The reduction enables us to take a step back and look more closely at our understanding of nature in light of the historical and cultural influence on our thinking.     

Role of zinc and copper ions in the pathogenetic mechanisms of Alzheimer’s and Parkinson’s diseases

Disbalance of zinc (Zn²⁺) and copper (Cu²⁺) ions in the central nervous system is involved in the pathogenesis of numerous neurodegenerative disorders such as multisystem atrophy, amyotrophic lateral sclerosis, Creutzfeldt-Jakob disease, Wilson-Konovalov disease, Alzheimer’s disease, and Parkinson’s disease. Among these, Alzheimer’s disease (AD) and Parkinson’s disease (PD) are the most frequent age-related neurodegenerative pathologies with disorders in Zn²⁺ and Cu²⁺ homeostasis playing a pivotal role in the mechanisms of pathogenesis. In this review we generalized and systematized current literature data concerning this problem. The interactions of Zn²⁺ and Cu²⁺ with amyloid precursor protein (APP), β-amyloid (Abeta), tau-protein, metallothioneins, and GSK3β are considered, as well as the role of these interactions in the generation of free radicals in AD and PD. Analysis of the literature suggests that the main factors of AD and PD pathogenesis (oxidative stress, structural disorders and aggregation of proteins, mitochondrial dysfunction, energy deficiency) that initiate a cascade of events resulting finally in the dysfunction of neuronal networks are mediated by the disbalance of Zn²⁺ and Cu²⁺.     

Structure and species richness of low-diversity floodplain forest on the Rio Tapajós, Eastern Amazonia, Brazil

Rivers in the Amazonian region have annual water level fluctuations varying from 6 to 20m, and the flooding period ranges from 50 to 270 days between the rising and falling phases. Along the rivers there are many different types of vegetation which are annually flooded. In order to study the variation of the species composition and structure of a forest that is seasonally flooded by a clear water river in Brazilian Amazonia 20km SW of Santarém, Pará State, Brazil, we surveyed three hectares, each divided in ten randomly placed rectangular quadrats (10×50m). The number of species per hectare ranged from 21 to 30. The number of trees varied from 242 to 741. Total basal area ranged from 0.70 to 10.9m2. Leguminosae was the most abundant and dominant family in the three hectares sampled. Couepia paraensis (Chrysobalanaceae), Campsiandra laurifolia (Leguminosae) and Leopoldinia pulchra (Palmae) were the most abundant species in the hectares sampled. Similarity indexes at species level varied from 46 to 60% between the three hectares sampled. The hectares studied have the lowest species richness observed in igapó floodplain forest of the Brazilian Amazonia. This may be correlated with the water type, soil condition and proximity of savanna.     

Complexity and developmental changes in the expression pattern of claudins at the blood–CSF barrier

The choroid plexus epithelium controls the movement of solutes between the blood and the cerebrospinal fluid. It has been considered as a functionally more immature interface during brain development than in adult. The anatomical basis of this barrier is the interepithelial choroidal junction whose tightness has been attributed to the presence of claudins. We used quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry to identify different claudins in the choroid plexuses of developing and adult rats. Claudin-1, -2, and -3 were highly and selectively expressed in the choroid plexus as compared to brain or parenchyma microvessels and were localized at epithelial junctions. Claudin-6, -9, -19, and -22 also displayed a previously undescribed choroidal selectivity, while claudin-4, -5, and -16 were enriched in the cerebral microvessels. The choroidal pattern of tight junction protein expression in prenatal brains was already complex and included occludin and zonula occludens proteins. It differed from the adult pattern in that the pore-forming claudin-2, claudin-9, and claudin-22 increased during development, while claudin-3 and claudin-6 decreased. Claudin-2 and claudin-11 presented a mirror image of abundance between lateral ventricle and fourth ventricle choroid plexuses. Imunohistochemical analysis of human fetal and postnatal brains for claudin-1, -2, and -3 demonstrated their early presence and localization at the apico-lateral border of the choroid plexus epithelial cells. Overall, choroidal epithelial tight junctions are already complex in developing brain. The observed differences in claudin expression between developing and adult choroid plexuses may indicate developmental differences in selective blood–cerebrospinal fluid transport functions.