EFFICACY OF METAMITRON IN APPLE THINNING IN SERBIA.

The thinning of fruits is a required pomotechnical measure in intensive fruit production which ensures the production of good quality fruits and high yields. Metamitron, known as inhibitor of photosynthesis, has been successfully used in the thinning of apple fruits. This study had the aim to determine the efficacy of metamitron on the thinning of apple fruits in the agroecological conditions of Serbia and to evaluate the possibility of its practical application. Two varieties of apples that are widely grown in Serbia, dared and Golden Delicious, have been chosen for this research. The experiments were carried out during 2011 and 2012 according to the EPPO PP 1/158 (3) method. Metamitron has shown a good efficacy in the thinning of apple fruits. The effect of metamitron on the thinning of apple fruits depends on multiple factors, pri- marily the application dose, time of application, apple variety, but also on the number of fruits developed. The best efficacy on the Idared variety was in plots where metamitron was applied at a dose of 1.1 kg ha⁻¹, once (in the growth stage when the fruits were 8 mm in diameter) or twice (in the growth stages when the fruits were 8 mm and 12 mm in diameter), when the number of developed fruits per tree is smaller, or 1.65 kg ha⁻¹ applied once when the fruits are 12 mm in size when a larger number of fruits per tree is developed. On the Golden Delicious variety, the best efficacy was in treatments when metamitron was applied twice (in the growth stages when the fruits were 8 mm and 12 mm in diameter) in quantities of 1.1 kg ha⁻¹, when less fruits per tree were formed or 1.65 kg ha⁻¹, applied once or twice when a larger number of fruits per tree were formed.

Blood-brain barrier function in intracerebral hemorrhage.

In this paper, we review current knowledge on blood-brain barrier (BBB) dysfunction following intracerebral hemorrhage (ICH). BBB disruption is a hallmark of ICH-induced brain injury. Such disruption contributes to edema formation, the influx of leukocytes, and the entry of potentially neuroactive agents into the perihematomal brain, all of which may contribute to brain injury. A range of factors have been implicated in inducing BBB disruption, including inflammatory mediators (e.g., cytokines and chemokines), thrombin, hemoglobin breakdown products, oxidative stress, complement, and matrix metalloproteinases. While there is interaction between some of these mediators, it is probable that prevention of ICH-induced BBB disruption will involve blocking multiple pathways or blocking a common end pathway (e.g., by stabilizing tight junction structure). While the effects of ICH on BBB passive permeability have been extensively examined, effects on other 'barrier' properties (metabolic and transport functions) have been less well-studied. However, recent data suggests that ICH can affect transport and that this may help protect the BBB and the brain. Indeed, it is possible in small bleeds that BBB disruption may be beneficial, and it is only in the presence of larger bleeds that disruption has detrimental effects.

Clinical presentation, treatment options and outcome in patients with bronchioloalveolar carcinoma.

PURPOSE: To determine the characteristics of bronchioloalveolar carcinoma (BAC) as a special clinical and pathological entity and to evaluate the effects of treatment options on survival of BAC patients. PATIENTS AND METHODS: The study was partially retrospective and partially prospective, non randomized. We evaluated the clinical presentation, smoking habits, radiographic findings, treatment and survival of 21 patients with BAC treated at our Institute from 2000-2004. RESULTS: Registered were 16 (76.2%) male and 5 (23.8%) female patients, most of them in the 6th and 7th decade of life. Among younger patients females prevailed. Most common symptoms were dyspnoea 15 (71.4%), cough 14 (66.6%) and bronchial hypersecretion 9 (42.8%). There were 5 (23.8%) smokers, 6 (28.6%) ex-smokers and 10 (47.6%) nonsmokers. Main radiographic findings were lung consolidation (9; 42.8%), diffuse interstitial infiltrates (6; 28.6%), solitary (4; 19.0%) and multiple pulmonary lesions (2; 9.5%). Surgery was performed in 8 (38.0%) patients and 5 of them received adjuvant radio- and chemotherapy, while the remaining received chemotherapy alone (9; 42.8%) and symptomatic treatment (4; 19.0%). The median survival was 25 months and 1-year survival 70%, regardless of stage. In the group of patients treated surgically 1- and 2-year survival rate was 100% and the median survival 33 months. In non-operated patients the median survival was 18 months and 1- and 2-year survival 55% and 25%, respectively. CONCLUSION: BAC is a special clinical and pathological form of adenocarcinoma of the lung. Surgical treatment is the best option for selected BAC patients. Survival is associated with the treatment modality. Larger scale studies are necessary to confirm these findings.

Inflammation and brain edema: new insights into the role of chemokines and their receptors.

Brain edema is associated with a variety of neuropathological conditions such as brain trauma, ischemic and hypoxic brain injury, central nervous system infection, acute attacks of multiple sclerosis, and brain tumors. A common finding is an inflammatory response, which may have a significant impact on brain edema formation. One critical event in the development of brain edema is blood-brain barrier (BBB) breakdown, which may be initiated and regulated by several proinflammatory mediators (oxidative mediators, adhesion molecules, cytokines, chemokines). These mediators not only regulate the magnitude of leukocyte extravasation into brain parenchyma, but also act directly on brain endothelial cells causing the loosening of junction complexes between endothelial cells, increasing brain endothelial barrier permeability, and causing vasogenic edema. Here we review junction structure at the BBB, the effects of pro-inflammatory mediators on that structure, and focus on the effects of chemokines at the BBB. New evidence indicates that chemokines (chemoattractant cytokines) do not merely direct leukocytes to areas of injury. They also have direct and indirect effects on the BBB leading to BBB disruption, facilitating entry of leukocytes into brain, and inducing vasogenic brain edema formation. Chemokine inhibition may be a new therapeutic target to reduce vasogenic brain edema.

Ischemia-induced endothelial cell dysfunction.

Hemorrhagic transformation upon reperfusion therapy has focused attention on ischemia-induced endothelial dysfunction. This study examined whether hyperglycemia may induce hemorrhagic transformation by enhancing endothelial mitochondrial damage during ischemia and whether preconditioning (PC) stimuli may limit ischemia-induced endothelial damage. In vivo, rats received 2.8 M D-glucose or arabinose (1 ml/100 g; i.p.) prior to undergoing two hours of middle cerebral artery occlusion and transcardiac fixation for electron microscopy. In vitro, brain endothelial cells were exposed to a PC impulse (short-term oxygen glucose deprivation; OGD) prior to an injurious event (5 hours OGD). Endothelial injury was assessed by measuring lactate dehydrogenase release. Hyperglycemia during cerebral ischemia resulted in marked changes in endothelial morphology and mitochondrial swelling. Thus, in the ischemic hemisphere, there was no evidence of endothelial mitochondrial swelling in normoglycemic rats (mean profile width 0.22 +/- 0.04 vs. 0.17 +/- 0.01 microm in contralateral hemisphere) but there was marked swelling in hyperglycemic rats (0.44 +/- 0.02 microm). In vitro, cells preconditioned with one hour of OGD one day prior to 5 hours of OGD, showed reduced lactate dehydrogenase release (p < 0.05). In conclusion, hyperglycemia may have specific adverse effects on endothelial cell mitochondria during ischemia. Preventing those effects may help to ameliorate blood-brain barrier disruption on reperfusion. Insights into how to prevent endothelial injury may come from determining the mechanisms involved in endothelial preconditioning.

The chemokine receptor CCR2 mediates the binding and internalization of monocyte chemoattractant protein-1 along brain microvessels.

Previous results from this laboratory revealed the presence of high-affinity saturable binding sites for monocyte chemoattractant protein-1 (MCP-1) along human brain microvessels (Andjelkovic et al., 1999; Andjelkovic and Pachter, 2000), which suggested that CC chemokine receptor 2 (CCR2), the recognized receptor for this chemokine, was expressed by the brain microvascular endothelium. To test the role of CCR2 directly in mediating MCP-1 interactions with the brain microvasculature, we assessed MCP-1 binding activity in murine brain microvessels isolated from wild-type mice and from CCR2 (-/-) mice engineered to lack this receptor. Results demonstrate that MCP-1 binding is greatly attenuated in microvessels prepared from CCR2 (-/-) mice compared with wild-type controls. Moreover, microvessels from wild-type mice exhibited MCP-1-induced downmodulation in MCP-1 binding and a recovery of binding activity that was not dependent on de novo protein synthesis. Furthermore, MCP-1 was shown to be internalized within wild-type microvessels, but not within microvessels obtained from CCR2 (-/-) mice, additionally demonstrating that CCR2 is obligatory for MCP-1 endocytosis. Last, internalization of MCP-1, but not transferrin, was observed to be inhibited by disruption of caveolae. Internalized MCP-1 also colocalized at some sites with caveolin-1, a major protein of caveolae, implying that this chemokine is endocytosed, in part, via nonclathrin-coated vesicles. These results prompt consideration that MCP-1 signals may be relayed across the blood-brain barrier by highly specialized interactions of this chemokine with its cognate receptor, CCR2, along brain microvascular endothelial cells.

Qualitative and quantitative analysis of monocyte transendothelial migration by confocal microscopy and three-dimensional image reconstruction.

A novel method for qualitative and quantitative analysis of monocyte transendothelial migration is described. By labeling monocytes and endothelial cells with different fluorophores, and utilizing confocal microscopy and three-dimensional image reconstruction, transmigrating monocytes were resolved and quantified within a subendothelial collagen gel. Comparison of monocyte migration across endothelial monolayers derived from human brain microvessels versus umbilical veins revealed diapedesis across brain endothelium to be significantly delayed. Inclusion of astrocytes within the subendothelial collagen gel resulted in the formation of an array of astrocytic processes that simulated the glia limitans surrounding brain microvessels in situ, thus yielding a more physiologic paradigm of the blood-brain barrier. By virtue of its unique capacity to provide information on the total number of migrating cells, this analytic approach overcomes significant caveats associated with sampling only aspects of the migration process. The potential adaptability of this method to computer-assisted analysis further enhances its prospective use in high-throughput screening.

Monocyte:astrocyte interactions regulate MCP-1 expression in both cell types.

As astrocytes are a source of monocyte chemoattractant protein-1 (MCP-1) and lie in close apposition to brain microvessels, interactions between astrocytes and infiltrating monocytes might regulate production of this chemokine. To investigate this possibility, a monocyte:astrocyte co-culture model was utilized to assess the respective roles of these two cell types in regulating MCP-1 production. Results indicate that, while neither monocytes nor astrocytes alone produce detectable levels of MCP-1, co-culture of these two cell types results in time-dependent production of this chemokine. Such production requires de novo protein synthesis and is dependent on physical contact between monocytes and astrocytes, involving engagement of the cell-adhesion molecules ICAM-1 and VCAM-1. Additionally, interleukin 1-beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) are soluble mediators of this response. These findings imply that monocyte extravasation into the CNS may be critically regulated at the blood-brain barrier by specialized monocyte:astrocyte interactions.

Characterization of binding sites for chemokines MCP-1 and MIP-1alpha on human brain microvessels.

The presence of binding sites for the beta chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) has recently been identified on human brain microvessels. We extend these findings in this report to reveal that such sites exemplify characteristics of the recognized major receptors for MCP-1 and MIP-1alpha: CCR2, and CCR1 and CCR5, respectively. Specifically, labeled MCP-1 binding to isolated brain microvessels was inhibited by unlabeled MCP-1 and MCP-3, the latter another CCR2 ligand, but not by MIP-1alpha. Inhibition of labeled MIP-1alpha binding was achieved with unlabeled MIP-1alpha and RANTES, the latter a beta chemokine that binds to both CCR1 and CCR5, but not by MCP-1. Labeled MIP-1alpha binding was also antagonized by unlabeled MCP-3, which is also recognized by CCR1, and MIP-1beta, which is a ligand for CCR5. Labeled MCP-1 and MIP-1alpha were further observed to be internalized within the endothelial cells of brain microvessels, following their binding to the microvascular surface at 37 degrees C. Additionally, exposure of microvessels to unlabeled MCP-1 or MIP-1alpha was accompanied by the initial loss and subsequent recovery of surface binding sites for these chemokines, which occurred on a time scale consistent with ligand-induced endocytosis and recycling. These collective features bear striking similarity to those that characterize interactions of MCP-1 and MIP-1alpha with their receptors on leukocytes and underscore the concept of cognate chemokine receptors on brain microvascular endothelium.

Expression of binding sites for beta chemokines on human astrocytes.

Astrocytes are major sources of chemokines and are thus critical effectors of central nervous system (CNS) inflammation. However, it is as yet unclear whether these cells, like leukocytes, also possess receptors for chemokines (CCRs). To address this issue, we utilized a novel fluorescence approach to detect qualitatively and quantitatively binding sites for biotinylated derivatives of the beta chemokines monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) on cultured human fetal astrocytes. Both chemokines were found to bind to the surface of astrocytes in a specific and saturable manner and with the high-affinity typical of these chemokines' binding to leukocyte CCRs. Binding of labeled MCP-1 and of labeled MIP-1alpha was antagonized by the respective unlabeled homologue but not by the unlabeled heterologous chemokine. Binding of labeled MCP-1 was also inhibited by unlabeled MCP-3, both of which are ligands for CCR2. In a parallel manner, binding of labeled MIP-1alpha was first shown to be attenuated by unlabeled RANTES, both of which recognize CCR1 and CCR5, and then separately antagonized by MCP-3 and MIP-1beta, which bind to CCR1 and CCR5, respectively. Finally, binding of both labeled chemokines was observed to be modulated in response to astrocyte stimulation by proinflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), further indicating that these binding sites are subject to regulation and, thus, likely to be physiologically responsive. Collectively, these results indicate that binding sites exhibiting characteristics of chemokine receptors exist on human astrocytes. Such sites might function in the recruitment of both astrocytes and leukocytes to specified brain regions during physiological and pathophysiological processes.

Visualization of chemokine binding sites on human brain microvessels.

The chemokines monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) aid in directing leukocytes to specific locales within the brain and spinal cord during central nervous system inflammation. However, it remains unclear how these chemokines exert their actions across a vascular barrier, raising speculation that interaction with endothelial cells might be required. Therefore, experiments were performed to determine whether binding domains for these chemokines exist along the outer surface of brain microvessels, a feature that could potentially relay chemokine signals from brain to blood. Using a biotinylated chemokine binding assay with confocal microscopy and three-dimensional image reconstruction, spatially resolved binding sites for MCP-1 and MIP-alpha around human brain microvessels were revealed for the first time. Binding of labeled MCP-1 and MIP-1alpha could be inhibited by unlabeled homologous but not heterologous chemokine, and was independent of the presence of heparan sulfate, laminin, or collagen in the subendothelial matrix. This is the first evidence of specific and separate binding domains for MCP-1 and MIP-1alpha on the parenchymal surface of microvessels, and highlights the prospect that specific interactions of chemokines with microvascular elements influence the extent and course of central nervous system inflammation.

Macrophages/microglial cells in human central nervous system during development: an immunohistochemical study.

The development of microglia and macrophages was studied in 14 human embryos and fetuses ranging in age from 4.5-13.5 gestational weeks (g.w.), using lectins, Ricinus communis agglutinin-1 [RCA-1], and Lycopersicon esculentum, tomato lectin (TL), which recognize macrophages and microglia, and antibodies for the macrophage antigen CD68. Lectin-positive (+) cells were observed at 4.5 g.w., the youngest age examined. They were detected in the leptomeninges around the neural tube, and only rarely were observed in the CNS parenchyma. At 5.5 g.w., lectin+ cells were present throughout the CNS parenchyma, and a portion of these cells could also be labeled with antibody to CD68. In subsequent weeks, both types of cells, lectin+ and CD68+/lectin+ cells co-existed and progressively developed typical microglial morphology. In addition, in double label experiments, an antibody that labels CD14 antigen present on monocytes, hematogenous precursors of tissue macrophages, did not label either lectin+ or CD68+/lectin+ cells in CNS parenchyma. Additional immunocytochemical studies with appropriate markers excluded the possibility that any of the cells described here were either astrocytes, oligodendrocytes, endothelial cells or neurons. Our finding that one class of cells can be labeled early only with lectins, while another can be labeled with both lectins and CD68 macrophage antibody, may reflect a different origin of microglia in the early embryonic CNS compared to the fetal stages. This subdivision appears to be maintained in the adult brains as well.

Myelin basic protein immunoreactivity in the human embryonic CNS.

Myelin basic protein (MBP) is a major myelin constituent produced by oligodendrocytes in the central nervous system (CNS). Expression of MBP was considered to be a marker for oligodendrocyte differentiation and myelination in the developing CNS. In this study, expression of myelin basic protein (MBP) and its messenger RNA (mRNA) was examined in human embryos and fetuses ranging in age from 5 to 20 gestational weeks (g.w.). We were able to demonstrate that MBP antibody labels cells in both human nervous and non-nervous tissues beginning from early embryonic life (5-6 g.w.). MBP positive (MBP+) cells were rounded, with either no cell processes or only 1-2 short processes, and were located in caudal regions of the CNS. MBP+ cells were also observed in the non-nervous tissue, such as leptomeninges, choroid plexus, and connective tissues. A number of MBP+ cells in nervous and non-nervous tissues were morphologically similar to macrophages and showed a positive reaction to macrophage-microglia markers: lectin (RCA-1) and the monoclonal antibody (EBM-11) to human macrophage antigen CD68, whereas they were negative for neuronal, astroglial, or marker for oligodendrocyte progenitors. At the same embryonic age, 5 g.w. and onward, the MBP mRNA was observed in the CNS by in situ hybridization. The results of this study show that MBP immune reaction is spread in a large area of the CNS prior to myelin appearance. In addition, for the first time it has been demonstrated that the same population of cells could be labelled with both MBP and macrophage markers. These results indicate that MBP, or MBP-related proteins, could represent a link between the immune and nervous system during early development. Thus, besides the well established role in myelination, these proteins might have an additional and still unknown function in development.

Central nervous system endothelium in neuroinflammatory, neuroinfectious, and neurodegenerative disease.

Accumulating evidence points toward a significant role for the microvascular endothelium in the pathogenesis of several neurologic conditions. This review highlights those biochemical, anatomical, and physiological features of the endothelium thought to be dysfunctional in these disease states, and elaborates on novel treatment modalities that target the endothelium.

Myelin basic protein immunoreactivity in the human embryonic CNS

Myelin basic protein (MBP) is a major myelin constituent produced by oligodendrocytes in the central nervous system (CNS). Expression of MBP was considered to be a marker for oligodendrocyte differentiation and myelination in the developing CNS. In this study, expression of myelin basic protein (MBP) and its messenger RNA (mRNA) was examined in human embryos and fetuses ranging in age from 5 to 20 gestational weeks (g.w.). We were able to demonstrate that MBP antibody labels cells in both human nervous and non-nervous tissues beginning from early embryonic life (5-6 g.w.). MBP positive (MBP+) cells were rounded, with either no cell processes or only 1-2 short processes, and were located in caudal regions of the CNS. MBP+ cells were also observed in the non-nervous tissue, such as leptomeninges, choroid plexus, and connective tissues. A number of MBP+ cells in nervous and non-nervous tissues were morphologically similar to macrophages and showed a positive reaction to macrophage-microglia markers: lectin (RCA-1) and the monoclonal antibody (EBM-11) to human macrophage antigen CD68, whereas they were negative for neuronal, astroglial, or marker for oligodendrocyte progenitors. At the same embryonic age, 5 g.w. and onward, the MBP mRNA was observed in the CNS by in situ hybridization. The results of this study show that MBP immune reaction is spread in a large area of the CNS prior to myelin appearance. In addition, for the first time it has been demonstrated that the same population of cells could be labelled with both MBP and macrophage markers. These results indicate that MBP, or MBP-related proteins, could represent a link between the immune and nervous system during early development. Thus, besides the well established role in myelination, these proteins might have an additional and still unknown function in development.