P397 PROGNOSTIC VALUE OF CORONARY CALCIUM IN PATIENTS WITH COVID–19 AND SUSPECTED INTERSTITIAL PNEUMONIA: A CASE–CONTROL STUDY

Background

Short–term prognosis of SARS–CoV2 infection is mainly conditioned by the extent and severity of COVID–19 interstitial pneumonia. Coexistence of cardiac disease is however important and independently associated with an adverse outcome. Coronary calcium (CAC), detected at the time of chest computed tomography, can be a useful prognostic tool, as suggested by some cohort studies.

Material and Methods

We performed a retrospective, multi–centre, case–control (1:2) study in 195 COVID–19 patients admitted from 01–03–2020 to 30–04–2020. Cases were consecutive patients died within 30 days or admitted to the Intensive Care Units for invasive ventilation during the hospitalization (primary outcome measure). Controls were age– and sex–matched patients surviving until 30 days without need for invasive ventilation. For each case, we selected two controls, matched by age and sex dividing cases in age strata of 10 years, assuring within each age stratum twice the number of controls with an identical gender proportion. CAC estimation was performed with a with a semi–quantitative score (0 to 30) based on 10 segments and 4 degrees of severity of the calcification. Estimation of interstitial pneumonia, was similarly performed with a semi–quantitative score (from 0 to 20), based on 5 lobes and 5 degrees of severity of interstitial involvement. CT scans were acquired according to a standard protocol for non–cardio–synchronized chest CT, always on a multi–detector scanner with at least 16 layers.

Results

The mean CAC value in cases was significantly higher (p = 0.001) compared to controls: 5,52±1,38 vs 3,28±0,54 (mean value ± 95% CI). The percentage of cases with moderate–severe CAC was significantly higher (p = 0.013) compared to controls (41.5% vs 22.8%, OR 2.27 95% CI 1.20–4.29; primary end–point of the study). In multivariate analysis, independent predictors of outcome were (in descending order): interstitial pneumonia severity score (Wald 8.143, p = 0.004), CC score (Wald 5.569, p = 0.018), and the LDH value on admission (Wald 3.335, p = 0.034).

Conclusions

In our case–control study, the severity and extent of CAC is the main prognostic factor for the occurrence of adverse clinical outcome, beside the severity of interstitial pneumonia. These data suggest that a semi–quantitative estimation of CAC, feasible on any CT detector without the need of dedicated software, is clinically useful for the prognostic assessment of patients with COVID–19 interstitial pneumonia.

P58 IMMEDIATE CORONARY ANGIOGRAPHY AND SYSTEMATIC TARGETED TEMPERATURE MANAGEMENT ARE ASSOCIATED WITH IMPROVED OUTCOME IN COMATOSE SURVIVORS OF CARDIAC ARREST

Background

Rapid and systematic access to coronary angiography (CAG) and target temperature management (TTM) might improve outcome in comatose patients who survive cardiac arrest (CA). However, there is controversy around indicating immediate CAG in the absence of transmural ischemia on the electrocardiogram after return of spontaneous circulation (ROSC). We evaluated the short– and long–term outcome of our retrospective cohort of patients undergoing systematic CAG and TTM, based on whether culprit lesion percutaneous coronary intervention (PCI) was performed.

Methods

All consecutive comatose CA survivors with no obvious extracardiac causes undergoing TTM were included. Analysis involved the entire population and subgroups, namely patients with initial unshockable rhythm, no ST–elevation on electrocardiogram, and good neurological recovery.

Results

We enrolled 107 patients with a median age of 64.9 (57.7–73.6) years. The initial rhythm was shockable in 83 (77.6%). Sixty–six (61.7%) patients underwent PCI. In–hospital survival was 71%. It was 78.8% and 58.5% in those undergoing or not PCI (p = 0.022), respectively. Age, time from CA to ROSC and culprit lesion PCI were independent predictors of in–hospital survival. Long–term survival was significantly higher in patients who underwent PCI (respectively 61.5% vs 34.1%; Log–rank: p = 0.002). Revascularization was associated with better outcomes regardless of initial rhythm (shockable vs non–shockable) and ST–deviation (elevation vs no–elevation), and improved the long–term survival of patients discharged with good neurological recovery.

Conclusion

Systematic CAG and revascularization, when indicated, were associated with higher survival in comatose patients undergoing TTM, regardless of initial rhythm and ST–deviation in the post–ROSC electrocardiogram. The benefit was sustained at long–term particularly in those with neurological recovery.

A novel process driving Alzheimer's disease validated in a mouse model: Therapeutic potential

Introduction

The neuronal mechanism driving Alzheimer's disease (AD) is incompletely understood.

Methods

Immunohistochemistry, pharmacology, biochemistry, and behavioral testing are employed in two pathological contexts—AD and a transgenic mouse model—to investigate T14, a 14mer peptide, as a key signaling molecule in the neuropathology.

Results

T14 increases in AD brains as the disease progresses and is conspicuous in 5XFAD mice, where its immunoreactivity corresponds to that seen in AD: neurons immunoreactive for T14 in proximity to T14‐immunoreactive plaques. NBP14 is a cyclized version of T14, which dose‐dependently displaces binding of its linear counterpart to alpha‐7 nicotinic receptors in AD brains. In 5XFAD mice, intranasal NBP14 for 14 weeks decreases brain amyloid and restores novel object recognition to that in wild‐types.

Discussion

These findings indicate that the T14 system, for which the signaling pathway is described here, contributes to the neuropathological process and that NBP14 warrants consideration for its therapeutic potential.

Gene expression profiling and enrichment functional analyses to compare coronary microvessels and cardiomyocytes in patients with hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is characterized by severe alterations of cardiac architecture and function involving cardiomyocytes (CM) and coronary microvessels (MV). Coronary microvascular dysfunction, cardiomyocyte hypertrophy and disarray, sarcomeric alterations and interstitial fibrosis are HCM features. The transcriptome profile associated with coronary MV and CM in HCM patients is presently unknown.

Purpose

Aim of this study was to improve knowledge of the molecular and biological pahways involved in HCM. To this purpose, the gene expression profile of coronary MV and CM was investigated.

Methods

Interventricular septum myectomies from patients with obstructive HCM and donors' hearts (CTR) were collected. Coronary MV (HCM=20, CTR=6) and CM (HCM=10, CTR=5) were laser capture microdissected. RNA-seq was performed by Illumina Nextseq 500, with 76 nt long single-reads. Adapter trimming and quality filtering of the sequenced reads were performed before alignment to the human reference genome. Univocally mapped reads estimated gene expression/sample. Normalized expressed gene levels were quantified. Statistical tests compared HCM and CTR to identify differentially expressed genes (DEG), i.e. up- and down-expressed genes in CM and MV samples. Functional enrichment analysis was performed. Biological categories, i.e. KEGG and Reactome pathways, Gene Ontology terms, protein domains in InterPro database, putative interactors collected in the Intact database and protein annotations in UniProt were considered for inter group comparison of DEGs.

Results

Transcriptome analysis identified 392 genes significantly up-regulated and 514 down-regulated in CM samples of HCM vs. CTR, while in MV 681 genes were up-regulated and 815 down-regulated. Although some DEGs were shared between MV and CM (26 and 146 are up- and down-expressed in both sample types), the majority of DEGs displayed a sample-specific pattern. A comparative functional analysis of DEGs highlighted some statistically enriched biological categories including an enrichment of phosphoproteins, with down-expressed genes both in CM (490) and MV (314). Other biological categories annotated as “ubiquitin-like protein conjugation” or “acetylation” in Uniprot database were enriched in down-regulated genes, both in MV and CM. Interestingly, “ribosomal protein” and “ribonucleoprotein” categories resulted as enriched up-regulated DEGs in MV. Conversely, the “citrullination” category was specifically present in annotations associated to down-regulated DEGs in MV from HCM compared to CTR.

Conclusions

Our preliminary results support the suitability of RNA-seq analysis to assess: i. the transcriptome profiles and pathways associated to coronary MV and CM; ii. the possible relationship/interplay of MV and CM profiles and HCM disease. The enrichment functional analysis provides preliminary data on candidate DEGs and target proteins for in vitro studies on HCM-related mechanisms.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Ministry of Health

Brain gliomas and growth factors: immunohistochemical, immunofluorescence, flow cytometry and RT-PCR profile in pediatric age

Gliomas represent over 50% of tumors occurring in children. Evidence suggests that glioma stem cells (GSCs), maintained by the transforming growth factor-beta (TGF-β1) pathway, and vascularization substantially contribute to tumor aggressiveness. The identification of important angiogenic factors such as vascular endothelial growth factor (VEGF) may represent a crucial step in the therapeutic approach against tumor growth and metastatic diffusion. The aim of this study was to identify the expression of TGF-β1, VEGF and VEGF-receptors in brain gliomas. Specimens of 16 gliomas and 4 controls from children aged 0.2-14 years were used in the study. Immunohistochemical analysis and gene expression study from specimens was performed. Flow cytometry analysis on GSCs was performed to ascertain the expression of VEGF and VEGF-R2 in the tumor stem cell compartment. Newly diagnosed gliomas mainly showed moderate to strong VEGF immunostaining and increased expression of pro-inflammatory molecules in glioma cells. The proportion of TGF-β1 positive endothelial cells was markedly lower in normal brain vessels compared to tumor vessels. These findings demonstrate that the glioma mass is constituted by a phenotypically immature anoxic central area with a proliferating hypoxic layer; the peripheral area is characterized by cell types with a higher degree of differentiation expressing pro-angiogenic factors. Our data have proven that GSCs play a central role in promoting glioma neovascularization. These findings are useful to understand glioma vascularization, have relevant implications in the therapeutic options and may favor new insights into stem cells biology and suggest therapeutic opportunities for the anti-vascular treatment strategy.

Receptor distribution studies

Receptor distribution studies have played a key role in the characterization of receptor systems (e.g. GABA_B, NMDA (GluNRs), and Neurokinin 1) and in generating hypotheses to exploit these systems as potential therapeutic targets. Distribution studies can provide important information on the potential role of candidate receptors in normal physiology/disease and alert for possible adverse effects of targeting the receptors. Moreover, they can provide valuable information relating to quantitative target engagement (e.g. % receptor occupancy) to drive mechanistic pharmacokinetic/pharmacodynamic (PK/PD) hypotheses for compounds in the Drug Discovery process. Finally, receptor distribution and quantitative target engagement studies can be used to validate truly translational technologies such as PET ligands and pharmacoEEG paradigms to facilitate bridging of the preclinical/clinical interface and thus increase probability of success.

Central administration of NPY or an NPY-Y5 selective agonist increase in vivo extracellular monoamine levels in mesocorticolimbic projecting areas

Selective NPY-Y5 antagonists are known to reduce NPY-evoked increase of food intake under free feeding conditions and drug-reinforced operant responding in rodents suggesting that NPY-Y5 receptors can regulate reinforcers, potentially by modulating the hypothalamic-limbic reward system. However, evidence published to date has revealed a limited expression of NPY-Y5 in the limbic areas. Thus, the first aim of the present study was to investigate the distribution of NPY-Y5 receptor binding sites in rat mesocorticolimbic projection areas such as the nucleus accumbens (NAc), medial prefrontal cortex (mPFC), and lateral hypothalamus (LH). Since mesocorticolimbic release of monoamines has been typically associated to the rewarding and motivational significance of reinforcers, we then compared the ability of NPY and an NPY-Y5 selective agonist, [cPP1-7,NPY19-23,Ala31,Aib32,Gln34]hPP, to evoke changes in extracellular monoamines from these brain regions using in vivo microdialysis techniques. Intracerebral doses of each compound were selected on the basis of those previously demonstrated to trigger food intake in a separate set of animals. We found that NPY-Y5 receptors were widely distributed in both the NAc and mPFC but not in the LH nuclei. Central administration of either NPY (4.5 nmol/rat) or the NPY-Y5 agonist (0.6 nmol/rat) induced a significant increase of dopamine (DA) output of up to 150% of basal values in the NAc. In addition, NPY induced a stepped increase of norepinephrine (NE) outflow in the NAc area. Also extracellular levels of NE levels were increased by both treatments in the mPFC (150% vs basal concentration). Hypothalamic monoamine levels were unaffected by both treatments. Extracellular serotonin (5-HT) levels were also unchanged in all regions. Given the NPY-Y5 agonist paralleled the in vivo ability of NPY to increase DA, these data suggest that the release of NPY may modulate behaviours associated to accumbal DA release such reward and reinforcement by, at least in part, acting on mesocorticolimbic NPY-Y5 receptors.

[3H]GR205171 displays similar NK1 receptor binding profile in gerbil and human brain

1 In this study, [(3)H]GR205171 (3(S)-(2-methoxy-5-(5-trifluoromethyltetrazol-1-yl)-phenylmethylamino)-2(S)-phenylpiperidine), a potent and selective NK1 receptor antagonist, was characterised in autoradiographic studies in gerbil brain and in binding experiments on homogenates from gerbil and human brain cortex and striatum. 2 In autoradiographic studies in gerbil brain, highest levels of [(3)H]GR205171 binding sites were observed in caudate putamen, nucleus accumbens, medial and cortical nuclei of the amygdala and intermediate levels were detected in the hypothalamus, basolateral amygdala, septum, and cortex. 3 Saturation experiments in homogenates of brain striatum from gerbil showed that [(3)H]GR205171 binds to a single receptor population with a pK(d) value of 10.8+/-0.2 and a B(max) value of 607+/-40 fmol mg(-1). A lower number of NK1 receptor sites was found in cortex, where a B(max) of 94+/-6 fmol mg(-1) protein was obtained. Saturation experiments performed on homogenates from brain striatum of two human subjects and brain cortex of three human subjects showed that [(3)H]GR205171 binds with pK(d) values not different from gerbil and B(max) values ranging from 318+/-51 to 432+/-27 fmol mg(-1) protein in striatum and from 59+/-1 to 74+/-21 fmol mg(-1) protein in cortex. The natural ligand [(3)H]Substance P (SP) bound with sub-nanomolar affinity to 15 and 6% sites compared to [(3)H]GR205171 in gerbil and human striatum, respectively. 4 In competition binding experiments, GR205171 and the NK1 receptor antagonists aprepitant (MK-869), L-733,060 and NKP-608 bound with similar pK(i) values in gerbil and human striatum, irrespective of the use of [(3)H]GR205171 or [(3)H]SP as radioligand. The following rank order was found in terms of pK(i) values: GR205171>aprepitant> or =L-733,060>NKP-608. In homologous displacement experiments in gerbil and human striatum, SP showed nanomolar affinity, whereas in [(3)H]GR205171 competition experiments SP bound with pIC(50) values in the micromolar range and Hill slopes significantly lower than one. 5 It is concluded that the similarities of [(3)H]GR205171 binding characteristics and pharmacology between gerbil and human in cortex and striatum support the use of gerbil in preclinical models to study the effects of NK1 receptor antagonists in the central nervous system.

Down-regulation of amygdala preprotachykinin A mRNA but not3H-SP receptor binding sites in subjects affected by mood disorders and schizophrenia

Increasing evidence suggests that substance P (SP) neurokinin-1 (NK1) receptors are involved in stress and emotional responses, representing a potential target for the treatment of anxiety and depression in humans. Given the important role of the amygdaloid complex in the regulation of emotional behavior, we examined the mRNA levels of preprotachykinin A [PPT-A, a precursor of both SP and neurokinin A (NKA)] and 3H-SP binding sites in the amygdala of patients affected by bipolar disorder, major depression or schizophrenia as compared with matched control individuals. By means of in situ hybridization, a significant reduction of PPT-A mRNA expression levels was detected in the three diagnostic groups, mainly in the basal, lateral and accessory basal amygdaloid nuclei, but not in the temporal cortical area proximal to the amygdala. Receptor autoradiography performed on adjacent sections showed no change in 3H-SP binding sites as compared with controls. No significant correlation was found between levels of PPT-A mRNA expression or binding sites and subject age, gender, hemisphere side, cause of death or history of substance misuse (marijuana, alcohol, cocaine/amphetamine). An inverse relationship between PPT-A mRNA expression levels and lifetime antipsychotic treatment (Fluphenazine) in the schizophrenic and bipolar disorder groups was found. Post-mortem delay was also negatively correlated with NK1 binding sites. The results confirm an involvement of the tachykinins in psychiatric disorders, suggesting there is a generalized impairment of the SP system in the amygdala in mood disorders and schizophrenia rather than this being a disease-related phenomenon.

Neurokinin 1 receptor and relative abundance of the short and long isoforms in the human brain

Substance P exerts its various biochemical effects mainly via interactions through neurokinin-1 receptors (NK1). Recently, the NK1 receptor has attracted considerable interest for its possible role in a variety of psychiatric disorders including depression and anxiety. However, little is known regarding the anatomical distribution of NK1 in the human central nervous system (CNS). Riboprobe in situ hybridization, quantitative PCR and in vitro autoradiography were performed. Highest NK1 mRNA levels were localized in the locus coeruleus and ventral striatum, while moderate hybridization signals were observed in the cerebral cortex (most abundant in the visual cortex), hippocampus and different amygdaloid nuclei. Very low levels of the NK1 mRNA were detected in the cerebellum and thalamus. In view of the existence of a long and short isoform of the NK1 receptor, it was of interest to assess whether there was a differential distribution of the two splice variants in the human CNS and peripheral tissues. A quantitative TaqMan PCR analysis showed that the long NK1 isoform was the most prevalent throughout the human brain, while in peripheral tissues the truncated form was the most represented. 3H-Substance P autoradiography revealed a good correlation between receptor binding sites and NK1 mRNA expression throughout the brain, with the highest levels of binding in the locus coeruleus. These results provide the anatomical evidence that the NK1 receptors have a strong association with neuronal systems relevant to mood regulation and stress in the human brain, but do not suggest a region-specific role of the two isoforms in the CNS.

Distribution of the messenger RNA for the small conductance calcium-activated potassium channel SK3 in the adult rat brain and correlation with immunoreactivity

Small conductance calcium-activated potassium channels are voltage independent potassium channels which modulate the firing patterns of neurons by activating the slow component of the afterhyperpolarization. The genes encoding a family of small conductance calcium-activated potassium channels have been cloned and up to now three known members have been described and named small conductance calcium-activated potassium channel type 1, small conductance calcium-activated potassium channel type 2 and small conductance calcium-activated potassium channel type 3; the distribution of their messenger RNA in the rat CNS has already been performed but only in a limited detail. The present study represents the first detailed analysis of small conductance calcium-activated potassium channel type 3 mRNA distribution in the adult rat brain and resulted in a strong to moderate expression of signal in medial habenular nucleus, substantia nigra compact part, suprachiasmatic nucleus, ventral tegmental area, lateral septum, dorsal raphe and locus coeruleus. Immunohistological experiments were also performed and confirmed the presence of small conductance calcium-activated potassium channel type 3 protein in medial habenular nucleus, locus coeruleus and dorsal raphe. Given the importance of dorsal raphe, locus coeruleus and substantia nigra/ventral tegmental area for serotonergic, noradrenergic and dopaminergic transmission respectively, our results pose the morphological basis for further studies on the action of small conductance calcium-activated potassium channel type 3 in serotonergic, noradrenergic and dopaminergic transmission.

Differential expression of SAPK isoforms in the rat brain. An in situ hybridisation study in the adult rat brain and during post-natal development

MAPK pathways transduce a broad variety of extracellular signals into cellular responses. Despite their pleiotropic effects and their ubiquitous distribution, surprisingly little is known about their involvement in the communication network of nerve cells. As a first step to elucidate the role of MAPK pathways in neuronal signalling, we studied the distribution of SAPK alpha/JNK2, SAPK beta/JNK3, and SAPK gamma/JNK1, three isoforms of SAPK/JNK, a stress-activated MAPK subfamily. We compared the mRNA localisation of the three main isoforms in the adult and developing rat brain using in situ hybridisation. In the adult brain, SAPK alpha and beta were widely but heterogeneously distributed, reproducing the pattern of a probe that does not discriminate the isoforms. Differently, high labelling for the SAPK gamma probe was exclusively localised in the endopiriform nucleus and medial habenula. Intermediate staining was detected in the hippocampus. During post-natal development, SAPK beta showed the same localisation as in the adult. Nevertheless, the semi-quantitative analysis of optical densities showed significantly different mRNA levels. In the adult, SAPK gamma signal was weak, whereas in newborn rats the labelling was intense and widely distributed. SAPK gamma mRNA levels decreased during development, to reach the low signals detected in the adult. These results suggest that in the central nervous system SAPK-type MAP kinases perform significant physiological functions which are particularly relevant during post-natal development. The distinct distribution patterns of SAPK isoforms in the adult rat brain support the hypothesis that separate functions are performed by the products of the three SAPK genes.

Localization of the messenger RNA for the c-Jun NH2-terminal kinase kinase in the adult and developing rat brain: an in situ hybridization study

Stress-activated protein kinase/extracellular signal-regulated protein kinase-1/c-Jun NH2-terminal kinase kinase is a dual-specificity kinase which phosphorylates and activates stress-activated protein kinase/c-Jun NH2-terminal kinase, a recently discovered mitogen-activated protein kinase that is stimulated by stressful stimuli and that regulates cellular transcriptional activity. The distribution of the messenger RNA encoding for stress-activated protein kinase/extracellular signal-regulated protein kinase-1 was evaluated in the adult and developing rat central nervous system. In situ hybridization with a 35S-labelled 45mer oligodeoxynucleotide probe was used to map the distribution of the stress-activated protein kinase/extracellular signal-regulated protein kinase-1 messenger RNA in postnatal day 1, 3, 6, 9, 12, 15, 18, 21 and adult rat brains. Specific labelling was generally associated with neuronal profiles. In the adult central nervous system, high hybridization signals were observed in the hippocampus, the granular layer of the cerebellum, the medial habenula, the anterodorsal thalamic nucleus, the red nucleus, the pontine nuclei, the facial nucleus, the motor and mesencephalic nuclei of the trigeminal nerve, the hypoglossal nucleus, the vestibular nucleus and the nucleus ambiguus. Intermediate levels were present in diencephalic and mesencephalic regions and in the neocortex, while basal ganglia displayed a low hybridization signal. In the developing brain, the heterogeneous distribution of the hybridization signal observed in the adult brain was already present, but in the hippocampus and basal ganglia the stress-activated protein kinase/extracellular signal-regulated protein kinase-1 messenger RNA levels were significantly higher at postnatal day 3 and during the second postnatal week than in the adult. The results show that stress-activated protein kinase/extracellular signal-regulated protein kinase-1 is widely expressed in the rat central nervous system and co-localizes with its substrate stress-activated protein kinase. The observed changes in stress-activated protein kinase/extracellular signal-regulated protein kinase-1 messenger RNA levels during postnatal development suggest a role for this protein in the maturation of brain circuits.

Stress activated protein kinases, a novel family of mitogen-activated protein kinases, are heterogeneously expressed in the adult rat brain and differentially distributed from extracellular-signal-regulated protein kinases

Mitogen-activated protein kinases are important mediators of signal transduction from the cell surface to the nucleus and their activation has been implicated in a wide array of physiological processes. The extracellular-signal-regulated kinases are the archetypal and best studied members of the mitogen activated protein kinases. Recently, additional subgroups of mitogen activated protein kinases have been identified which exhibit distinct regulatory elements, substrate specificity and respond to diverse extracellular stimuli. Among these newly identified protein kinases are the rat stress-activated protein kinases. Despite a rapidly expanding literature on the biochemical properties of stress-activated protein kinases no anatomical data are yet available. In the present study, we have investigated the regional distribution of messenger RNA transcripts for stress-activated protein kinases in the adult rat central nervous system and compared this distribution to that observed for extracellular-signal-regulated kinases. Intense labelling for stress-activated protein kinases could be detected in discrete brain areas with high levels in hippocampus, neocortex and some nuclei of the brain stem. The apparent hybridization signal appeared to be selectively neuronal. Stress-activated protein kinases and extracellular-signal-regulated kinases hybridization patterns appeared generally dissimilar although a certain degree of co-expression in some brain areas, such as the hippocampal formation, could be observed. These results reveal an extreme complexity in the mitogen-activated protein kinase signalling pathway and suggest the existence of parallel mitogen-activated protein kinase cascades that can be activated independently or in some cases simultaneously, by extracellular stimuli.

Comparative receptor autoradiography of ex vivo and in vitro [3H]dizocilpine binding in mouse brain after middle cerebral artery occlusion

In the present study the in vitro and ex vivo distributions of [3H]dizocilpine binding sites in mouse brain after middle cerebral artery occlusion (MCA-O) were compared using receptor autoradiography. The distribution patterns of [3H]dizocilpine binding sites obtained in vitro and ex vivo in normal mouse brain were the same with the highest densities occurring in the hippocampus and cerebral cortex. MCA-O had little or no effect on the in vitro binding density for at least 24 hr post-ischaemia. However after 2-3 days binding densities in the region of infarct were significantly reduced compared to the contralateral cerebral cortex. Further reductions occurred after 5-7 days. By contrast ex vivo [3H]dizocilpine binding was reduced in the infarcted area by 78.7 +/- 4% within 2 hr of the ischaemic insult and at all subsequent times binding was reduced by more than 75%. Ex vivo binding after ischaemia was always less than 30% of in vitro binding and this decrease was apparent within 2 hr of the ischaemic insult whereas in vitro binding was maintained at control levels for at least 24 hr. The neuroprotective activity of the NMDA antagonists dizocilpine and CGP 37849 in this model at different times after MCA-O was assessed. The time scale for receptor access following MCA-O is discussed and it is suggested that although the population of NMDA receptors is maintained in the infarct region for some days access to them in vivo may be sufficiently impaired within 2 or 4 hr of ischaemic insult to reduce the neuroprotective activity of NMDA antagonists after this time.

[Medium molecular weight uremic toxins and endogenous polyamines. Behavior of polymorphonuclear leukocyte chemotaxis with respect to chromatographic peaks of dialysate and standard polyamines]

The aim of our study is to evaluate the eventual activity of the total dialysate of two uremic nephrectomized patients in recirculating dialysis and the chromatographic peak of the dialysate fractionated by Sephadex column G 15 on PMN chemotaxis. Only the total dialysate and the chromatographic peak B showed inhibition of chemotaxis. On the contrary the commercial polyamines in the same concentration range, and the other chromatographic peaks, containing polyamines too, did not revealed inhibition. Our data show, therefore, that the chemotaxis inhibition could be due to the middle-molecules present in the peak B, rather than the polyamines itself. Polyamines were determined by dansylation method, separated by thin layer chromatography and quantified by spectrofluorimeter. Chemotaxis was evaluated using the modified Boyden chamber.

The effect of rifamycin SV on neutrophil functions in patients with rheumatoid arthritis

The chemotaxis, phagocytic capacity and reducing activity of neutrophils derived from peripheral blood of patients with rheumatoid arthritis (RA) did not differ from those of control. However, some significant differences between neutrophils from rheumatic and healthy subjects emerged in the presence of rifamycin SV. The chemotactic response of neutrophils from patients with RA was activated by rifamycin SV, whereas cells from controls did not orient their locomotion towards the drug. Moreover, incubation of RA patient's cells with rifamycin SV in vitro depressed phagocytic and reducing activities; the same treatment on normal cells failed to alter these functions. A correlation between improvement of clinical symptoms after treatment of RA by local infiltration with rifamycin SV, observed by others, and the impairment of phagocytosis and NBT reduction, here described, was suggested.

Defective responsiveness to natural and pharmacological molecules of neutrophil locomotion in rheumatoid arthritis disease

Neutrophils derived from peripheral blood of patients with rheumatoid arthritis (RA) exhibited a defective responsiveness to natural mediators of inflammation, namely histamine and serotonin, and to the anti-inflammatory drugs ibuprofen and naproxen, in spite of the fact that the basic status of motility was normal. Not even pretreatment of granulocytes with substances restored the capacity to modulate the random and directional locomotion. This neutrophil functional defect was correlated with an anomalous response to rifamycin SV, previously observed in rheumatic states.

[Relationship between structure and function of a chemotactic factor for human leukocytes]

Casein, a phosphoprotein forming aggregates in solution, exerts chemotactic activity for human neutrophils. The protein was filtered on Sephadex G 100 to obtain fractions of homogeneous mol. weight and the column fractions were tested for chemotactic activity. The chemotactic activity was found only in the lighter peak, which was then digested by trypsin. The digested material was purified by filtration through AcA-54 and the 6.000 M.W. peptide containing the most phosphate groups and tyrosines resulted chemotactic for PMN. Most likely the phosphate groups are important in chemotactic recognition.

[Effect of rifamycin SV on neutrophil functions in patients with rheumatoid arthritis]

The antibiotic rifamycin SV (RSV) has been successfully used by others on the local treatment of rheumatoid arthritis (R.A.). Since polymorphonuclear leukocytes (PMNL) are involved in the synovial inflammatory process we tested the 'in vitro' effect of RSV on PMNL functions, such as locomotion and phagocytosis. PMNL locomotion was evaluated by using modified Boyden Chamber and phagocytosis was tested by the number of yeast particles ingested and by NBT reduction. The, the functions of PMNL derived from 7 R.A. patients in therapy only with non steroidal anti-inflammatory drugs were compared with those of PMNL from 14 patients with non inflammatory disease (osteoporosis and osteoarthrosis) in the same therapy and with neutrophils from healthy subjects. It was demonstrated that PMNL derived from patients with both R.A. and non inflammatory disease activated their directional locomotion towards RSV, on the contrary, cells from healthy subjects were unresponsive. Moreover, only patients with R.A. showed a defective phagocytic capacity and a depression in NBT reducing activity, when PMNL were treated with RSV. This phenomenon might be correlated with beneficial effect observed after local treatment of R.A. with RSV.

[Effect of a component of human lymphocyte dialysate on the motor activity of polymorphonuclear leukocytes]

Lymphocyte dialysates obtained from healthy volunteers and leukemic subject were chromatographed on Bio-Gel P-4. Partially purified fractions were assayed for neutrophil locomotion: a positive chemokinetic effect and no chemotactic activity was observed in both samples.