AMF communities associated to Vitis vinifera in an Italian vineyard subjected to integrated pest management at two different phenological stages

Vitis vinifera L. is an economically important crop that can be influenced by soil microorganisms, including arbuscular mycorrhizal fungi (AMF), that establish symbiotic associations with its roots. AMF have beneficial effects on grapevine performance improving water use efficiency and replant success. Most grapevine varieties are susceptible to various diseases, and integrated pest management (IPM) is one of the emerging approaches to perform pest control. In the present study, we examined the AMF communities present in the soil associated to the roots of V. vinifera cv. Pinot Noir (comparing them to those present in a soil not affected by grapevine roots), in a vineyard subjected to IPM at two different phenological stages, using 454 Roche sequencing technology. We proposed a new approach to analyze sequencing data. Most of the taxa were included in the family Glomeraceae. In particular, Glomus sp. Rhizophagus sp. and Septoglomus viscosum were present. The family Archeosporaceae was represented only by the genus Archeospora sp. Different AMF communities were found in the two soils and the importance of the phenological stage in regulating AMF biodiversity was assessed.

Inositols and metabolic disorders: From farm to bedside

Inositol and its derivates are catching interest in metabolism since taking part in several physiological processes, including endocrine modulation. Through several mechanisms mostly mediated by insulin signaling, these compounds regulate the activities of several hormones and are essential in oocytes maturation. It is interesting to point out the contribution of an inositol deficiency in the development of several diseases, mainly in the metabolic and endocrine setting. Inositols derive from both diet and endogenous production; among causes of inositol deficiency reduced dietary intake, increased catabolism and/or excretion, decreased biosynthesis, inhibition of gut and cellular uptake and altered microbiota could be considered. Mounting direct and indirect evidence suggests that the two main isoforms (Myo-inositol-inositol, D-chiro-inositol) are implied in glycemic and lipidic metabolism and supplementation yield a beneficial effect on these parameters without hazards for health. Moreover, they have a role in polycystic ovary syndrome, acting as insulin-sensitizing agents and free radical scavengers, helping to regulate metabolism and promoting ovulation. The aim of this narrative review is to discuss the role of inositols in metabolic function disorders paying attention to whether these compounds could be efficacious and safe as a therapeutic agent with a focus on dietary intake and the role of gut microbiota.

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Inositol deficiency is implicated in the development of metabolic and endocrine diseases.

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Inositol compounds could be safe food supplement to restore metabolic imbalance.

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Inositol compounds partly derive from microbiota phytases entering in bacterial metabolism.

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Diet inositol content has a role in shaping gut microbiota and the host metabolism.

Metaproteomic characterization of theVitis vinifera rhizosphere

The rhizosphere is a hotspot of microbial activity where the release of root exudates stimulates bacterial density and diversity. The majority of the bacterial cells in soil are viable, unculturable, but active. Proteomic tools could be useful in gaining information about microbial community activity and to better understand the real interactions between roots and soil. The aim of this work was to characterize the bacterial community associated with Vitis vinifera cv. Pinot Noir roots using a metaproteome approach. Our results confirmed the large potential of proteomics in describing the environmental microbial communities and their activities: in particular, we showed that bacteria belonging to Streptomyces, Bacillus, Bradyrhizobium, Burkholderia and Pseudomonas genera are the most active in protein expression. Concerning the biological activity of these genera in the rhizosphere, we observed the exclusive presence of the phosphorus metabolic process and the regulation of primary metabolic processes. To our knowledge, this is the first study reporting the rhizosphere proteome of V. vinifera, describing the bacterial community structure and activity of an important ecosystem for the Italian landscape, agriculture and economy.

Antifungal activity of essential oils against azole-resistant and azole-susceptible vaginal Candida glabrata strains

Candida glabrata is an opportunistic pathogen, associated with endocarditis, meningitis, and disseminated disease, and also with complicated vaginitis. Essential oils derived from aromatic plants are known in traditional medicine as antimicrobial agents and have antifungal properties. The aim of this work was to evaluate whether 12 tested essential oils (tea tree, laurel, anise, basil, bergamot, lavender, mint, oregano, grapefruit, rosemary, winter savory, and ginger) could have a transverse effect on C. glabrata sensitive strains but above all on strains resistant to the three main azole antifungals used (clotrimazole, fluconazole, itraconazole). For this reason, different strains of C. glabrata, vaginal isolated, were characterized (disk diffusion assay, minimal inhibitory concentration) with respect to their response to such antifungals. Electron microscopy analyses were performed to examine cellular damages in depth. Subsequently, we wanted to evaluate the effect of the oils on human cells to estimate their potential cytotoxicity. Oregano and winter savory were the two most effective essential oils, inducing growth inhibition, cell damage of C. glabrata strains (both sensitive and resistant to azole antifungal drugs), and medium–high level of toxicity against human keratinocytes. The results of this work support the research for new alternatives or complementary therapies against vaginal candidiasis.

Sensitivity of Candida albicans to essential oils: are they an alternative to antifungal agents?

AIMS

Candida albicans is an important opportunistic pathogen, responsible for the majority of yeast infections in humans. Essential oils, extracted from aromatic plants, are well-known antimicrobial agents, characterized by a broad spectrum of activities, including antifungal properties. The aim of this work was to assess the sensitivity of 30 different vaginal isolated strains of C. albicans to 12 essential oils, compared to the three main used drugs (clotrimazole, fluconazole and itraconazole).

METHODS AND RESULTS

Thirty strains of C. albicans were isolated from vaginal swab on CHROMagar^™ Candida. The agar disc diffusion method was employed to determine the sensitivity to the essential oils. The antifungal activity of the essential oils and antifungal drugs (clotrimazole, itraconazole and fluconazole) were investigated using a microdilution method. Transmission and scanning electron microscopy analyses were performed to get a deep inside on cellular damages. Mint, basil, lavender, tea tree oil, winter savory and oregano essential oils inhibited both the growth and the activity of C. albicans more efficiently than clotrimazole. Damages induced by essential oils at the cellular level were stronger than those caused by clotrimazole.

CONCLUSIONS

Candida albicans is more sensitive to different essential oils compared to the main used drugs. Moreover, the essential oil affected mainly the cell wall and the membranes of the yeast.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this work support the research for new alternatives or complementary therapies against vaginal candidiasis.

Abstract P1-08-31: Putative role of genetic variants of eNOS in survival and toxicity of patients given antiangiogenic therapy

Background: The development of tumor angiogensis is mainly driven by vascular endothelial growth factor (VEGF), which is strongly overexpressed in many cancers. VEGF induces the expression of the endothelial nitric oxide (NO) synthase (eNOS) and the resultant overproduction of NO may be associated with recruitment of inflammatory cells, disruption of endothelial barrier, edema and impaired drug delivery within tumors (1). Functional polymorphisms in the eNOS gene, including -786C>T and 894G>T, have been associated with impaired production of NO and higher incidence of hypertension (HT) (2), diabetic nephropathy (3) and glaucoma (4). Since suppression of VEGF-eNOS signal transduction by antiangiogenic drugs may normalize tumor vasculature by restoring interstitial fluid pressure and drug distribution in tumors, but may induce HT in patients, the purpose of this study was to examine the association between the major eNOS variants -786C>T and 894G>T with treatment outcome and risk of HT in metastatic breast cancer (MBC) patients given bevacizumab. Methods: Sixty-five MBC patients given bevacizumab as per approved indication were enrolled. Main characteristics were: mean age 49.5 years (range 29-73) at first diagnosis, 53 years (range 34-74) at metastatic progression and PS 0-1. Four subjects with HT and 1 patient with compensated cardiovascular disease were also included. First-line chemotherapy for metastatic disease was taxol plus bevacizumab. Germline DNA was extracted from peripheral blood with the Qiamp Mini Kit (Qiagen, Milano, Italy) and examined for eNOS -786C>T and 894G>T variants by Real Time PCR (Life Sciences 7900HT platform) and automatic sequencing (Life Sciences 3100 Avant). The study was approved by the local Ethics Committee. Results: Genotype frequencies are reported below (Table 1). The presence of -786TT genotype was associated with longer PFS compared with the other genotypes (median PFS 95%CI, CC/CT = 9 vs TT = 12 months, Log-rank [Mantel Cox] test p = 0.0066), but not with any grade of HT. Also the 894GT/TT was associated with longer PFS compaed with the GG homozygous wild-type genotype (median PFS 95%CI, GG = 7,5 vs GT/TT = 10 months, Log-rank [Mantel-Cox] test p = 0,0497). The incidence and severity of HT did not vary among genotypes. Conclusion: Patients bearing deficient eNOS variant did not experience higher risk or severity of HT with respect to the wild-type allele but enjoied a longer PFS.

Table 1. Genotype frequenciesSNPFrequencies%Frequencies%Frequencies%-786C>TCCCTTT 37%33.8%26.2%894G>TGGGTTT 41.5%53.8%4.6%

References

1. Goel S et al. Physiol Rev 2011;91:1071

2. Niu W, Qi Y. PLoS One 2011;6:e24266

3. Rahimi Z et al. Dis Markers 2013;34:437

4. Awadalla MS et al. Invest Ophtalmol Vis Sci 2013;54:2108.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-31.

Abstract P5-17-06: The deficient eNOS c.894G>T genotype is not associated with increased severity of hypertension and proteinuria in breast cancer patients receiving bevacizumab

Background. Tumor angiogenesis is a complex process involving a wide array of effector molecules and stromal cells. In tumor tissue, vasculature is structurally and functionally abnormal, causing elevated interstitial pressure and irregular perfusion. The expression of vascular endothelial growth factor (VEGF), the most important angiogenic factor, is enhanced in many tumors. VEGF may induce nitric oxide (NO) production via up-regulation of the endothelial NO synthase (eNOS, NOS3) and the resultant overproduction of NO is associated with vasodilation and edema within tumors (Goel S et al. Physiol Rev 2011;91:1071). eNOS plays an important physiologic role in maintaining blood pressure homeostasis and vascular integrity by providing constitutive release of NO in endothelial cells. Functional variants of the eNOS gene, including the single-nucleotide polymorphism rs1799983 (c.894G>T, p. Asp298Glu) at codon 298, have been associated with reduced function of eNOS and higher incidence of hypertension (HT) (Niu W, Qi Y. PLoS One 2011;6:e24266).

Purpose. Since suppression of VEGF-eNOS axis by anti-angiogenic therapies is considered a causative factor of HT in patients, the purpose of this study was to examine whether the major eNOS non-synonymous variant c.894G>T may be associated with increased risk of developing hypertension (HT) and proteinuria (PU) in breast cancer patients treated with bevacizumab.

Patients and methods. Forty-one metastatic breast cancer patients given bevacizumab as per standard of care were enrolled. Main characteristics were: median age 49.5 years (range 29–73) at first diagnosis, 53 years (range 34–74) at metastatic disease; PS 0–1 in all patients; 4 subjects with hypertension and 1 patient with compensated cardiovascular disease at diagnosis. Twenty-six subjects had received neoadjuvant or adjuvant chemotherapy based on anthracycline and taxane; first-line chemotherapy for metastatic disease was paclitaxel plus bevacizumab for all patients; 14 subjects received hormone-therapy for metastatic disease (range 1–5 lines). Germline DNA was extracted from peripheral blood and used to screen patients for eNOS c.894G>T variant by automatic sequencing. The study was approved by the local Ethics Committee.

Results. Three patients (7.3%) were homozygous variant c.894TT, 12 (29.3%) homozygous wild-type c.894GG and the remaining 26 (63.4%) were heterozygous c.894GT. The c.894TT patients had no HT or PU at baseline and developed grade (G) 1, 2, 2 HT, respectively, and in one case PU during treatment. G1, 2 and 3 HT developed in 4, 5 and 2 c.894GG subjects, respectively, while PU was observed in 7/12 (58%) patients. The full range of HT grades and PU were observed in heterozygous subjects. Thirty-seven patients achieved one of the following: partial remission, minimal response or stable disease upon treatment with bevacizumab in combination with chemotherapy; 3 subjects had progressive disease and 1 was not evaluable.

Conclusions. The presence of the mutant T allele of c.894G>T is not associated with increased severity of HT and PU; therefore, bevacizumab can be administered at no increased risk in TT patients with respect to the wild-type GG population.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-17-06.

Hypoxic-ischaemic brain damage in immature rats: effects of adrenoceptor modulation

The purpose of the present study was to evaluate the role of adrenergic receptors in the cascade leading to hypoxic-ischaemic brain injury in neonatal rats. The effect of adrenergic agents (prazosin, yohimbine, idazoxan and clonidine) administered before or after hypoxia-ischaemia was evaluated with respect to mortality and brain injury. Rat pups of either 7 or 8 days of age were subjected to unilateral carotid artery ligation combined with hypoxia (6% or 8% O2 in N2). The mortality was higher in hypoxic-ischaemic groups pre-treated with the alpha-adrenergic receptor antagonists prazosin (48%) or yohimbine (53%) than in saline controls (7%). After 2 weeks the severity of the brain injury was evaluated in the surviving rats. Unilateral brain injury, evaluated by brain weight deficit of the injured ipsilateral hemisphere compared with the contralateral hemisphere, was 17.8 +/- 4.9% and 27.1 +/- 4.0% in pre- and post-treated saline groups, respectively. Post-treatment with clonidine, an alpha2-adrenergic agonist, reduced brain injury by 45% (p < 0.05) compared with saline controls. Pre-treatment with the same drug was not effective. Idazoxan had no effect on brain injury in this animal model. The results indicate that activation of central alpha2-adrenergic or imidazole receptors provides neuroprotection during reperfusion after hypoxic-ischaemic brain injury in neonatal rats.

NMDA-induced 45Ca release in the dentate gyrus of newborn rats: in vivo microdialysis study

This in vivo study, aimed at detecting the N-methyl-D-aspartate (NMDA) evoked Ca(2+)-induced Ca(2+) release from intracellular stores in the neonatal rat brain, demonstrates that the application of 5 mM N-methyl-D-aspartate via a microdialysis probe for 20 min to the dentate gyrus (DG) of halotane-anesthetized 7 day-old (postnatal day 7, PND 7) rats induces a prolonged decrease in Ca(2+) concentration in an initially calcium-free dialysis medium, indicative of a drop in the extracellular concentration of Ca(2+) and Ca(2+) influx to neurons. In parallel experiments, a huge NMDA-evoked release of 45Ca from the pre-labeled endogenous Ca(2+) pool was observed and interpreted as the expression of intracellular Ca(2+) release. Dantrolene (100 microM) significantly inhibited the NMDA-induced 45Ca release, whereas 250 microM ryanodine exerted an unspecific biphasic effect. Autoradiographic and immunocytochemical detection of ryanodine receptors and calbindin D(28K), respectively, in the hippocampal region of PND 7 rats displayed a pronounced expression of [3H]ryanodine binding sites in the DG, but only a slight immunoreactivity of calbindin D(28K). Plastic changes in neurons or excitotoxic neuronal damage induced by the activation of NMDA receptors are mediated by Ca(2+) signals, resulting from an influx of extracellular Ca(2+), and also in some neurons, from the release of intracellular Ca(2+). Our previous in vivo microdialysis experiments visualized NMDA-evoked 45Ca release in the adult rat dentate gyrus, attributable to Ca(2+)-induced Ca(2+) release from the ryanodine-sensitive pool. An additional role of calbindin in the mechanism of this phenomenon has been suggested. This aspect has not been studied in vivo in newborn rats. Our present results indicate that the release of 45Ca from the prelabeled intracellular, dantrolene-sensitive Ca(2+) pool in the DG neurons of immature rats, most probably representing a phenomenon of Ca(2+)-induced Ca(2+) release, significantly participates in the generation of NMDA receptor-mediated intracellular Ca(2+) signals, whereas the role of calbindin D(28K) in the mechanism of 45Ca release is negligible.

Chemokine and inflammatory cell response to hypoxia-ischemia in immature rats

Hypoxia-ischemia induces an inflammatory response in the immature central nervous system that may be important for development of brain injury. Recent data implicate that chemoattractant cytokines, chemokines, are involved in the recruitment of immune cells. The aim was to study alpha- and beta-chemokines in relation to the temporal activation of inflammatory cells after hypoxia-ischemia in immature rats. Hypoxia-ischemia was induced in 7-day-old rats (left carotid artery occlusion + 7.7% oxygen). The pups were decapitated at different times after the insult. Immunohistochemistry was used for evaluation of the inflammatory cell response and RT-PCR to analyze the cytokine mRNA and chemokine mRNA expression. A distinct interleukin-1beta and tumor necrosis factor-alpha cytokine expression was found 0-24 h after hypoxia-ischemia that was accompanied by induction of alpha-chemokines (growth related gene and macrophage inflammatory protein-2). In the next phase, the beta2-integrin expression was increased (12 h and onward) and neutrophils transiently invaded the vessels and tissue in the infarct region. The mRNA induction for the beta-chemokines macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, and RANTES preceded the expression of markers for lymphocytes [cluster of differentiation (CD)4, CD8], microglia/macrophages (MHC I), and natural killer cells in the infarct area. The activation of microglia/macrophages, CD4 lymphocytes, and astroglia persisted up to at least 42 d of postnatal age implicating a chronic component of immunoinflammatory activation. The expression of mRNA for alpha- and beta-chemokines preceded the appearance of immune cells suggesting that these molecules may have a role in the inflammatory response to insults in the immature central nervous system.

Protective effects of moderate hypothermia after neonatal hypoxia-ischemia: short- and long-term outcome

We have previously shown that mild hypothermia applied after hypoxia-ischemia in newborn piglets and rats reduces brain injury evaluated 3-7 d after the insult. The aim of the present study was to assess the neuroprotective efficacy of hypothermia with respect to short- (neuropathology) and long-term (neuropathology and sensorimotor function) outcome after hypoxia-ischemia in 7-d-old rats. One hundred fourteen animals from 13 litters survived either 1 or 6 wk after a hypoxic-ischemic insult. The animals were randomized to either 1) normothermic recovery for the whole 1- or 6-wk period or 2) cooling to a rectal temperature of 32.0 degrees C for the first 6 h followed by normothermic recovery with the dam. Hypothermia offered a uniform protection of 27, 35, 28, and 25% in cerebral cortex, hippocampus, basal ganglia, and thalamus, respectively, in the 1-wk survivors (n = 32). The corresponding values for the 6-wk survivors (n = 61) were 22, 28, 37, and 35%. There was a significant correlation between sensorimotor performance and infarct volume (r = 0.66; p < 0.001). However, the sensorimotor function was not significantly improved by hypothermia if all animals were included, but in female pups the total functional score was higher in the hypothermia group (150 +/- 35 versus 100 +/- 34, p < 0.0007) which corresponded to a marked (51%) reduction of the neuropathology score in this subgroup. This is the first neonatal study to show a long-term histopathologic protection of the brain after posthypoxic hypothermia.

Temporal changes of regional glucose use, blood flow, and microtubule-associated protein 2 immunostaining after hypoxia-ischemia in the immature rat brain

In a situation with normal CBF and without increased energy utilization, increased glucose utilization (CMRglc) can be a sign of impaired mitochondrial metabolism, which may be an early step in the injury cascade during reperfusion after hypoxia-ischemia (HI). Seven-day-old rats underwent unilateral carotid artery ligation and 70 minutes of HI. At 3, 6, 12, 24, and 48 or 72 hours after the insult, the CMRglc was measured by the 2-deoxyglucose method, and CBF by the iodoantipyrine method. These were compared with hematoxylin-eosin staining and microtubule-associated protein 2 (MAP 2) immunostaining in adjacent sections. In the ipsilateral hemisphere, there appeared regions with increased CMRglc compared with the contralateral hemisphere 3 to 12 hours after HI that also showed partial loss of MAP 2 immunostaining and early ischemic changes. These areas receded, leaving central glucose hypoutilizing areas with complete loss of MAP 2 immunostaining and histologic infarction, surrounded by only a rim of tissue with increased CMRglc. At 24 and 72 hours after the insult, no regions with increased CMRglc remained. Despite loss of MAP 2 immunostaining and histologic signs of infarction at 24 hours, cortical CBF was not reduced until 48 hours after HI, whereas the CBF in the caudate-putamen already was decreased compared with the contralateral side at 3 hours after HI. In conclusion, early reperfusion is characterized by glucose hyperutilizing areas in the cerebral cortex, followed by a secondary phase with low CMRglc and infarction.

Sensorimotor function and neuropathology five to six weeks after hypoxia-ischemia in seven-day-old rats

Various therapeutic interventions after hypoxia-ischemia (HI) have been shown to reduce brain injury in the short-term perspective, but it remains uncertain whether such findings are accompanied by long-term functional and structural improvements. HI was induced in 7-d-old rats as follows. The left carotid artery was ligated, and the rat was exposed to 100 min of hypoxia (7.70% oxygen in nitrogen). At postnatal d 42 the rats were assessed using four sensorimotor tests. The results were correlated with the extent of brain damage expressed as volume of deficit of the left hemisphere as percent of the right hemisphere. In the grip-traction test, the time to falling was 2.2 times shorter in the HI animals compared with controls (p < 0.01). Asymmetries of limb-placing and foot-faults (p < 0.001) were detected in HI animals, and the motor function was abnormal in the postural reflex test (p < 0.001). We found a moderate correspondence between functional and neuropathologic outcome (r = 0.842, p < 0.001). A set of four easily performed sensorimotor tests is presented for the long-term evaluation of neurologic function in the 7-d-old rat model of HI.

The calpain proteolytic system in neonatal hypoxic-ischemia

Neonatal rats were subjected to transient cerebral hypoxic-ischemia (HI, unilateral occlusion of the common carotid artery +7.70% O2 for 100 min) and allowed to recover for up to 14 days. Calpain caseinolytic activity was found to increase in both hemispheres for at least 20 hr. Hypoxic exposure per se increased the activity of calpains, more pronounced in a membrane-associated fraction, probably through interaction with cellular components, whereas HI introduced a loss of activity, most likely through consumption and loss of proteases. Consecutive tissue sections were stained with antibodies against calpastatin, alpha-fodrin, the 150-kDa breakdown product of alpha-fodrin (FBDP, marker of calpain proteolysis) or microtubule-associated protein 2 (MAP-2, marker of dendrosomatic neuronal injury). Areas with brain injury displayed a distinct loss of MAP-2, which clearly delineated the infarct. FBDP accumulated in injured and borderline regions ipsilaterally, and a less conspicuous, transient increase in FBDP also occurred in the contralateral hemisphere, especially in the white matter. The cytosolic fraction (CF) and the membrane and microsomal fraction (MMF) of cortical tissue were subjected to Western blotting and stained with antibodies against calpain, calpastatin and the 150-kDa breakdown product of alpha-fodrin (FBDP). Calpain immunoreactivity decreased bilaterally in the CF during the insult (62-68% of controls) and remained significantly lower during early recovery, whereas the MMF showed no significant changes. This translocation of calpains coincided with the appearance of FBDP in the ipsilateral, HI hemisphere, displaying a significantly higher level of FBDP from immediately after the insult until at least 1 day of recovery (204-292% of controls). No significant changes in FBDP were found in the contralateral, undamaged hemisphere, despite translocation of calpains in both hemispheres, a prerequisite for calpain activation. This discrepancy may be related to changes in the endogenous inhibitor, calpastatin. Calpastatin protein was found to decrease during and shortly after HI in the ipsilateral, but not the contralateral, hemisphere. The inhibitory activity of calpastatin also tended to decrease after HI, indicating that a reduction of calpastatin may be necessary for extensive calpain activation to occur. The mRNA of m-calpain increased in the HI hemisphere 48 hr after the insult (167%, p < 0.001), a time point when the protein was also increased. In summary, our findings indicate that calpains are activated during HI and in the early phase of reperfusion after HI, preceding neuronal death.

Magnesium and the N-methyl-D-aspartate receptor antagonist dizocilpine maleate neither increase glucose use nor induce a 72-kilodalton heat shock protein expression in the immature rat brain

In adult rats N-methyl-D-aspartate receptor (NMDAR) antagonists increase glucose use and induce a 72-kD heat shock protein (HSP72) expression in limbic system areas that later undergo neuronal necrosis, which have limited the clinical development of these drugs. Dizocilpine maleate (MK-801) and magnesium sulfate (MgSO4) reduce hypoxic-ischemic brain injury in immature animals, but the effects on HSP72 expression and glucose use are unknown. Seven-day-old rats received injections of either vehicle (control), 0.5 or 1.0 mg/kg MK-801, or 2 or 4 mmol/kg MgSO4. Glucose utilization was measured with the deoxyglucose method, 30 min, 48 h, and 4 d after injection. HSP72 immunostaining was evaluated 4 or 24 h after injection. Both doses of MK-801 and 4 mmol/kg MgSO4 induced a temporary decrease in glucose use in the posterior cingulate and retrosplenial cortex, the CA1 and CA3 subfields of the hippocampus, the caudoputamen, and the parietal cortex. Doses of 2 mmol/kg MgSO4 did not affect glucose use in any structure. Neuronal HSP72 expression was not found in any drug-treated rats. In conclusion, neither MK-801 nor MgSO4 increased glucose use in the limbic system and did not induce HSP72 expression, suggesting that NMDAR antagonists lack direct neurotoxicity in the immature brain.

Neonatal cerebral hypoxia-ischemia: the effect of adenosine receptor antagonists

The effects of nonselective (theophylline), A1-(DPCPX) or A2A-selective (SCH 58261) adenosine receptor antagonists administered before or after neonatal hypoxia-ischemia (HI) were studied on the extent of brain injury in 7-day-old rats evaluated after 14 days. A possible effect of theophylline (20 mg/kg) on expression of immediate early genes was studied with in situ hybridization. Theophylline (20, 30 or 60 mg/kg) given prior to HI reduced brain damage by 48% (P < 0.001), 36% (P < 0.01) and 34% (P < 0.05), respectively, compared to control rats. This effect was not explained by changes in temperature, cerebral blood flow, blood gas/acid base status or blood glucose during the insult. Theophylline enhanced the upregulation of c-fos and NFGI-A during reperfusion but did not prevent the decrease in adenosine A1 receptor mRNA. Posttreatment with SCH 58261 (0.2 or 2 mg/kg) reduced brain damage by 19% (P < 0.05) and 14% (NS), respectively, compared to control rats which was unrelated to the core temperature. DPCPX (2 or 10 mg/kg) had no effect on the development of brain injury. In conclusion, nonselective and A2A adenosine receptor antagonists reduced brain injury in a model of HI in immature animals.

Hypoxia-ischaemia model in the 7-day-old rat: possibilities and shortcomings

The Levene model in 7-day-old rats is the most often used model of hypoxia-ischaemia (HI) in immature animals. The rat central nervous system is immature at birth and corresponds neurodevelopmentally to the term human infant during the second postnatal week. The Levene model of HI differs from clinical asphyxia with respect to the unilateral distribution of brain injury and lack of multi-organ dysfunction. Furthermore, it does not allow cardiovascular monitoring or repeated blood sampling. On the other hand, the progressive nature of HI bears many similarities to birth asphyxia with regard to blood flow changes and cellular metabolic derangements. The model is well characterized, easy to carry out and the low cost allows inclusion of a sufficient number of animals for dose-response evaluation of neuroprotective agents. In addition, it provides the unique opportunity of long-term evaluation of neuropathological and functional outcome.

Enhanced expression of interleukin (IL)-1 and IL-6 messenger RNA and bioactive protein after hypoxia-ischemia in neonatal rats

The effect of hypoxia-ischemia (HI) on IL-1, and IL-6 bioactivity in relation to expression of IL-1 alpha, IL-1 beta, and IL-6 mRNA was studied, and the neuroprotective efficacy of IL-1 receptor antagonist (IL-1ra) was evaluated in neonatal rats. HI was induced in 7-d-old rats by unilateral carotid artery ligation and hypoxia for 70-100 min. Animals were killed at different time points up to 14 d after HI, and brains were analyzed for IL-1 and IL-6 bioactivity using bioassays and for mRNA for IL-1 alpha, IL-1 beta, and IL-6 with reverse transcription followed by a polymerase chain reaction. In separate animals, IL-1ra was administered intracerebrally before or after HI, and the extent of brain injury was assessed 14 d after HI. A transient increase of IL-1 bioactivity occurred after HI, reaching a peak at 6 h of recovery. IL-1 beta mRNA followed a similar time course but attained maximum expression at 3 h. IL-6 bioactivity and mRNA were also stimulated by HI and followed a similar time course as IL-1. Pretreatment with IL-1ra reduced HI brain damage from 54.4 +/- 9.3 to 41.4 +/- 10.0% (p < or = 0.01), and IL-1ra posttreatment increased the proportion of animals devoid of brain injury (40%) compared with vehicle-treated controls (13%) (p < or = 0.05). In conclusion, a transient activation of IL-1 and IL-6 occurred after HI, and IL-1ra reduced HI brain injury to a moderate degree.

Microglia-astrocyte interactions after cortisone treatment in a neonatal hypoxia-ischemia model

Microglial and astrocyte responses to glucocorticoid pretreatment in the neonate exposed to hypoxia-ischemia (HI) are largely unknown. The expression of microglial antigens and astrocytic proliferation was compared in neonatal rats exposed to HI with and without cortisone. HI was induced in 7 day old rats. One group of rats received cortisone within 24 h of birth. Immunocytochemical and immunoblot investigations were performed. Monoclonal antibodies (OX18 and OX42) were used for the detection of the major histocompatibility complex (MHC) class I antigens and complement receptor 3 (CR3) respectively. Antibodies directed against glial fibrillary acidic protein (GFAP) and microtubule associated protein II (MAP II) were used to evaluate the extent of brain damage. Cortisone treatment provoked a decline in the number of microglial cells but did not modify GFAP levels in control rats which were not exposed to HI. Neuronal damage was similar in control and cortisone treated rats exposed to HI. There were also similarities in the expression of CR3 antigens on microglia. However microglial cells expressing MHC class I antigens were less prevalent in rats exposed to HI only. Cortisone pretreatment enhanced the expression of MHC class I antigens. Astrocytic proliferation was intense in rats exposed to HI; however in rats treated with cortisone and exposed to HI there was a drastic reduction in astrocytic proliferation. In conclusion it is suggested that microglia which survive cortisone pretreatment become over-activated thereby preventing astrocytic proliferation.

Development of brain damage after neonatal hypoxia-ischemia: excitatory amino acids and cysteine

The aim of this study was to investigate the possible role of excitatory amino acids (EAAs) and cysteine in the development of brain damage after hypoxia-ischemia (HI) in neonates. In a rat model of neonatal HI, changes in extracellular (ec) amino acids in cerebral cortex were measured with microdialysis and correlated with the extent of brain damage at the site of probe placement. Extracellular concentrations of glutamate, aspartate and cysteine increased during HI and remained elevated during reperfusion. During HI the pattern of EAA changes was the same in the infarcted, undamaged and border zone regions. During reperfusion, however, the ec concentrations of glutamate, aspartate and cysteine were higher in infarcted and border zone areas compared to undamaged tissue. HI also produced a slight increase of tissue concentration of cysteine and decrease of tissue concentration of glutamate in parietal cortex of the HI hemisphere. The effect of cysteine on brain damage induced by HI and glutamate was also investigated. A subtoxic dose of cysteine potentiated glutamate toxicity in the arcuate nucleus and enhanced brain infarction after HI in neonatal rats. The results show that in neonatal HI the extracellular levels of EAAs during HI are not directly related to brain injury but the EAA levels during reflow predict the extent of infarction. Cysteine increases HI-induced brain injury and potentiates glutamate toxicity in neonatal rats. Speculatively, elevated level of cysteine during reperfusion may participate in the excitotoxic cascade leading to brain injury.

The effect of long term caffeine treatment on hypoxic-ischemic brain damage in the neonate

There is considerable concern over the widespread use of caffeine during and after pregnancy. We have therefore examined the effect of perinatal caffeine use on the vulnerability of the immature brain to hypoxic ischemia (HI). Rat pups were exposed to caffeine during the first 7 d after birth by addition of a low or a high dose (0.3 or 0.8 g/L) of caffeine to the drinking water of their dams. At 7 d the pups were exposed to unilateral carotid occlusion+exposure to 7.70% oxygen for 100 min. The extent of HI brain damage was evaluated 2 wk after the insult. The effects of caffeine on A1 and A2a receptors, A1 mRNA and A2a mRNA, were examined by receptor autoradiography and in situ hybridization. Caffeine, theobromine, theophylline, and paraxanthine were analyzed in plasma of separate animals. Exposure to caffeine reduced HI brain damage from 40.3 +/- 3.2% in controls to 29.8 +/- 4.0% (p < 0.05) in low dose and 33.7 +/- 3.9% (NS) in the high dose group. The A1 receptor density measured as [3H]-1,3-dipropyl-8-cyclopentyl xanthine ([3H]-DPCPX) binding was not significantly affected after low dose caffeine but increased in the brain of rat pups in the high dose group. The A2a receptor density measured as [3H]-2[p-(2-carbonylethyl)-phenethylamino]-5'-N- ethylcarboxamidoadenosine ([3H]-CGS 21680) binding and the expression of A1 mRNA and A2a mRNA were not altered by caffeine treatment. In conclusion, low dose caffeine exposure (plasma levels corresponding to umbilical cord plasma in newborns of coffee-consuming mothers) reduced HI brain damage by 30% in 7-d-old rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Degradation of fodrin and MAP 2 after neonatal cerebral hypoxic-ischemia

Neonatal rats were subjected to transient cerebral hypoxic-ischemia (unilateral occlusion of the common carotid artery + 7.70% O2 for 100 min) and allowed to recover for 3 h, 24 h, 2 days or 14 days. Consecutive tissue sections were stained with antibodies against alpha-fodrin, the 150 kDa breakdown product of alpha-fodrin (FBDP, marker of calpain proteolysis) or microtubule associated protein 2 (MAP 2, marker of dendrosomatic neuronal injury). Cortical tissue pieces were subjected to Western blotting using the antibody against the FBDP. Areas with brain injury displayed a distinct loss of MAP 2 which clearly delineated the infarct. FBDP accumulated in injured and borderline regions ipsilaterally and a less conspicuous, transient increase in FBDP also occurred in the contralateral hemisphere, especially in the white matter. A reciprocal staining pattern could be seen in the cerebral cortex, i.e. loss of MAP 2 and accumulation of FBDP, most pronounced 14 days after the insult. Fodrin and MAP 2 are known calpain substrates, and degradation of these proteins preceded neuronal degeneration, indicating that these proteases may be involved in the early events triggering the cascades leading to neuronal death.

Microglia activation after neonatal hypoxic-ischemia

The inflammatory response following hypoxic-ischemia (HI) in the neonate is largely unknown. Presently, the expression of microglial antigens and the beta-amyloid precursor protein (APP) were studied in relation to a dendrosomatic marker of neuronal injury (microtubule associated protein II; MAP II). HI was induced in 7-day-old rats by the combined unilateral carotid ligation and hypoxia. The pups (n = 23) were perfusion fixed 2-3 h, 24 h, 2-4 days and 14 days after HI and compared to sham-operated controls (n = 6). Antibodies were used for detection of the major histocompatibility complex II (OX-6), major histocompatibility complex I (OX-18) and complement receptor type 3 (OX-42), APP (APP 676-695) and MAP II (monoclonal MAP II) antigens. There was a transient APP expression 2-3 h after HI. A slight increase of microglial antigens (OX-18) was seen in the white matter 2 h after HI followed by a marked increase of OX-18, OX-6, OX-42 antigens 24 h-3-4 days in most injured regions with exception of the thalamus where a delayed (14 days) microglial response was seen. The latter event was parallelled by a delayed loss of MAP II. In conclusion, intense microglial expression occurs after neonatal HI either with an acute or delayed time-course depending on brain region.

Hypoxic-ischemic injury in the neonatal rat brain: effects of pre- and post-treatment with the glutamate release inhibitor BW1003C87

In a model of perinatal hypoxia-ischemia (HI) we examined the neuroprotective efficacy of pre- and post-treatment with the glutamate release inhibitor BW1003C87 [5-(2,3,5-trichlorophenyl)-2,4-diamino-pyrimidine). Ipsilateral brain damage developed in 99% of rat pups subjected to HI (unilateral common carotid artery ligation and 100 min of 7.7% oxygen exposure) with a 26 +/- 16% (mean +/- S.D.) weight deficit of the damaged hemisphere 2 weeks after the insult. Pre-treatment with BW1003C87 (10 mg/kg intraperitoneally) reduced the brain damage by 46% (P < 0.05). A higher dose (20 mg/kg) of pre-treatment was not tolerated. Administration of BW1003C87 did not affect the rectal temperature of the rats. Post-treatment with BW1003C87 (10-30 mg/kg) offered no neuroprotection in this model. In conclusion, there was a neuroprotective effect from pre- but not post-treatment with BW1003C87 in this model, supporting the concept that intra-ischemic excitatory amino acid release is important for development of brain damage. The lack of post-treatment effect indicates that BW1003C87 did not attenuate deleterious EAA cycling during reflow in the neonatal brain.

Changes in c-fos mRNA in the neonatal rat brain following hypoxic ischemia

We used quantitative in situ hybridization to study changes in the expression of c-fos following hypoxic-ischemia (H-I) in the neonatal rat brain. 7-day-old rat pups were subjected to a unilateral ligation of the common carotid artery followed by a 2 h 15 min hypoxic period (7.7% O2 in N2). This resulted in the expected ipsilateral infarction of cortex, lateral hippocampus, lateral-superior aspects of the striatum and the white matter of the corpus callosum. Brain damage was not seen in the contralateral hemisphere subjected only to hypoxia. c-fos mRNA levels increased in the contralateral hemisphere immediately after the hypoxia and had returned towards normal levels 2 h thereafter. In the ipsilateral hemisphere, the expression of c-fos was delayed but very marked at 2 h. Animals subjected only to hypoxia showed little or no increase in c-fos mRNA. Thus the earliest recorded increase in c-fos after hypoxic ischemia, which occurred on the non-ischemic, contralateral side, may represent a generalized response to a more localized insult.

Changes in adenosine receptors in the neonatal rat brain following hypoxic ischemia

We used quantitative in situ hybridization and receptor autoradiography to study changes in adenosine receptors following hypoxia-ischemia (H-I) in the neonatal rat brain. Seven-day-old rat pups were subjected to a unilateral ligation of the common carotid artery followed by a 2 h 15 min hypoxic period (7.7% O2 in N2). Adenosine A1 receptor mRNA in cortex and several parts of hippocampus, and A2a mRNA was decreased in the ligated hemisphere 0 h, 1 h and 2 h following hypoxia. The binding of the A1 receptor selective antagonist [3H]8-cyclopentyl-1,3-dipropylxanthine (DPCPX) in the presence or in the absence of GTP decreased immediately after the hypoxic period in both hemispheres and returned thereafter gradually towards control. These results show that there are rapid changes in A1 receptor number on both sides of the brain, and of adenosine A1 and A2a receptor mRNA in the hemisphere that would later develop infarction. Decreases in adenosine receptors may worsen H-I brain damage and have consequences for the use of adenosine directed therapy.

[Splenic infarct in the computed tomogram]

Splenic infarcts are represented by wedge-shaped, oval or linear areas. Haemorrhagic infarcts are characterised by being hyperdense. Disseminated infarction occurs predominantly in myeloproliferative diseases. During the early stages, the infarct appears as an ill-defined hypodense defect, with non-homogeneous contrast enhancement. During the acute and sub-acute stage, the density of the infarct is low and there is no contrast enhancement. During the chronic stage, its density increases and there is slight contrast enhancement. Complications following splenic infarcts, such as abscesses, bleeding and rupture can be demonstrated by CT with great accuracy. Problems in differential diagnosis may occur if there are atypical manifestations of the infarct, with respect to abscess or leukaemic infiltrations.