In the M. tuberculosis H37Rv and in the human tubercular strains isolated from patients, the loca... more In the M. tuberculosis H37Rv and in the human tubercular strains isolated from patients, the localization of genetic determinants of drug-resistance to antitubercular chemotherapeutic drugs in current use was studied. Data obtained through the treatment of the resistanct strains with acridine dyes and ethidium bromide, and the analysis of irreversible elimination of resistance markers support the hypothesis of an extrachromosomal locus for the p-aminosalicylic acid (PAS)-resistance and confirm a chromosomal mutation for the isoniazid (INH), ethambutol (EM), rifampicin (R/AMP)-resistances, in all the levels reached in training or selected in wild strains. In the PAS-revertants recovered after treatment with mutagenic agents, a loss by degrees of resistance levels was observed. In a mycobacterial strain biresistant to PAS and streptomycin (Sm) the Authors were able to find a loss of the mono-resistance to Sm only. The significance of these results is discussed in terms of plasmid (s) ...
In the present report evaluation of the possible metabolic changes in partially revertants of M. ... more In the present report evaluation of the possible metabolic changes in partially revertants of M. tuberculosis var. hominis, reisolated from strains at high levels of drug-resistance after treatment with mutagenic agents, was reported. Based on the data presented here, it must be concluded that no significant biological and biochemical differences in mycobacterial cells revertant from high mutants mono-resistant to four aminoglycosides (Sm, Kana, Vio, Neo) and p-aminonasalicylic acid (PAS) are to be found.
Incorporation of labelled precursors into neutral lipids and phospholipids of hypertrophied guine... more Incorporation of labelled precursors into neutral lipids and phospholipids of hypertrophied guinea-pig cardiac ventricles during normobaric hypoxia (breathing gas mixture of N2: O2, 9: 91%) was studied. The lipids of the heart were isotopically labelled in vivo with [1-14C] palmitate and [2-3H] glycerol, and, after a period of 2 hours, the incorporation of the two injected precursors into mitochondrial and microsomal fractions was determined. Eighty hours after the onset of the hypoxic treatment, the specific activities of isolated lipids showed a more elevated incorporation into lipid classes of hypoxic right and left ventricles with respect to that of the control. For both precursors, the percent increase of incorporation into microsomal and mitochondrial neutral lipids was higher than into phospholipids. In the microsomal fraction the increase of 14C-radioactivity incorporation was more pronounced than 3H-incorporation. 3H/14C incorporation ratio appeared decreased in hypoxic ven...
The effect of simple and mixed copper(II) complexes of L-tryptophan (trp) and L-phenylalanine (ph... more The effect of simple and mixed copper(II) complexes of L-tryptophan (trp) and L-phenylalanine (phe) on the gastric acid secretion was investigated in Shay rats. Graded doses (from 15 to 75 mg/kg) of [Cu(trp)2(H2O)], [Cu(phe)2(H2O)] and [Cu(trp)(phe)(H2O)], administered i.g., caused a progressive inhibition of gastric acid secretion. The antisecretory activity of the mixed complex, [Cu(trp)(phe)(H2O)], was significantly greater (ID50 = 33 +/- 3 mg/kg) than that of the simple complexes [Cu(trp)2(H2O)] (ID50 = 48 +/- 3 mg/kg) and [Cu(phe)2(H2O)] (ID50 = 43 +/- 3 mg/kg). At the experimental conditions of intragastric pH, the different biological activities were directly related to the percentage of neutral species present in solution as determined by means of potentiometric measurements (at 37 degrees, I = 0.15 mol dm-3 in NaClO4). A possible mechanism of action of the investigated compounds is discussed.
The genotype distribution of two gene polymorphisms, previously associated with peripheral artery... more The genotype distribution of two gene polymorphisms, previously associated with peripheral artery disease (PAD), has been evaluated in a population of diabetic (DPAD) and non-diabetic (NDPAD) patients affected by symptomatic PAD (stages II-IV). A decreased frequency of the AA genotype of rs5498 (ICAM-1) was observed in the PAD subjects compared to controls but this result did not reach statistical significance (p=0.06 by chi-squared test). On the contrary, a significant increase in the frequency of the GG homozygous genotype of rs248793 (SRD5A1) was observed in the PAD patient group in comparison to controls (p=0.01). These data confirm that the GG genotype of rs248793 in the SRD5A1 gene is significantly associated with symptomatic PAD and show a trend towards a stronger association with the non-diabetic status.
We describe the inhibitory effect of A beta (25-35) fragment of amyloid-beta peptide and bradykin... more We describe the inhibitory effect of A beta (25-35) fragment of amyloid-beta peptide and bradykinin (BK) on phosphatidylcholine (PtdCho) metabolism in immortalized rat brain GP8.39 endothelial cells (EC). Cultures were incubated either with A beta for 24-48 h, or with BK for 30 min-4 h. The peroxidation indices (malondialdehyde, conjugated dienes) and lactate dehydrogenase (LDH) release significantly increased after A beta peptide (10-50 microM) treatment. The BK (10 microM) stimulation of cells brought about an increase in conjugated dienes and LDH release only after 4 h. Following 24 h treatment with 50 microM A beta peptide, the [Me-3H]choline incorporation into PtdCho strongly decreased while the [3H]choline release increased, indicating PtdCho hydrolysis. The effect was most likely due to peptide prooxidant effect. After 4 h preincubation with BK, the [Me-3H]choline incorporation into PtdCho strongly decreased, but no significant [3H]choline release was found. Following long-te...
A brief description of the importance of axonal transport for nerve cell metabolism, with a discu... more A brief description of the importance of axonal transport for nerve cell metabolism, with a discussion of some special features affecting the retina and optic nerve. A connection is made between this transport and a variety of eye diseases in the light of recent publications. In particular, the role played by axonal transport in the course of diseases of the optic nerve (papilledema), elevation of IOP and retinopathies with vascular origins is summarized.
Molecular and chemical neuropathology / sponsored by the International Society for Neurochemistry and the World Federation of Neurology and research groups on neurochemistry and cerebrospinal fluid, 1989
In the present work, the hypothesis that the increased rapid intracellular transport of newly-syn... more In the present work, the hypothesis that the increased rapid intracellular transport of newly-synthesized material along the axons of a regenerating system is sustained by an alteration of the transport of proteolipid complexes through subcellular compartments of a neuronal cell body was tested by a biochemical methodology. The motoneurons of spinal cord ventral horn, 4 wk after unilateral lesion (crush) of cervico-thoracic nerves of the rabbit at the level of brachial plexus, were chosen as the model system of regeneration. A time-staggered procedure of in vivo and in vitro double labeling with metabolic precursors, such as [3H]-choline, [14C]-choline, [3H]-fucose, and [14C]-fucose, was used. Subcellular fractions (RER, SER, Golgi apparatus, and plasma membranes) of ventral horn tissue, taken from spinal cord hemisections (regenerating and contralateral side), were further isolated. Twenty-eight days after axotomy, we did not observe any change of intracellular transport kinetics (...
We examined the effects of age on RNA and lipid formation by whole retina and optic nerve in vitr... more We examined the effects of age on RNA and lipid formation by whole retina and optic nerve in vitro. Male Wistar rats, aged 4, 12, and 24 mo, were used. From the results obtained the following conclusions may be drawn: 1. In assaying the lipid biosynthesis during aging, a striking difference between the retina and optic nerve clearly emerged; 2. In isolated retina, [3H]uridine incorporation into RNA was relatively constant at the three ages, whereas both [14C]palmitate and [3H]choline incorporation into lipids showed a substantial increase in rats at 24 mo of age compared with those at 4 mo; 3. In contrast, in the optic nerve of the oldest rats, compared with the youngest, a significant decrease of [14C]acetate and [14C]palmitate incorporation into acylglycerols, cerebrosides, and phospholipids was found. Each fatty acid precursor label was incorporated to a proportion that reflected the typical acyl group composition of individual lipids; 4. Following labeling of the optic nerve wit...
The synthesis and chemical behaviour of N-(benzothiazolyl-2-carbonyl)-N-1-(2-thiazolyl)hydrazines... more The synthesis and chemical behaviour of N-(benzothiazolyl-2-carbonyl)-N-1-(2-thiazolyl)hydrazines is described. All the products were screened in vitro for antimicrobial activity. Some of them were found to give positive results.
International Journal of Developmental Neuroscience, 1998
The permeability!surface area product "PS# of ð0! 03 CŁarachidonate at the blood!retina and blood... more The permeability!surface area product "PS# of ð0! 03 CŁarachidonate at the blood!retina and blood! brain barrier was determined by short carotid perfusion in young Wistar rats 0 or 5 h after recovery period following complete cerebral ischemia induced by temporary cardiac arrest[ For the retina and structures of visual system\ hypothalamus and olfactory bulb there was no signi_cant di}erence over sham!operated rats among mean PSs[ For cortex\ hippocampus and striatum\ signi_cant increases were found at both time intervals of recovery after cardiac arrest[ The ischemia!reperfusion model was characterized by a signi_cant increase in tissue conjugated diene in the hippocampus and microsomal lysophosphatidylcholine acyltransferase activity in the cortex[ Consistent with these _ndings\ we also show ultrastructural evidence mainly represented by partial opening of interendothelial junctions and mild signs of tissue edema in surrounding neuropil\ suggesting barrier leakiness predominantly in the cortex\ hippocampus and striatum but almost absent in the retina microvessels[ Our results indicate that ischemia!reperfusion does a}ect in~ux through blood!brain barrier into regional structures of rat central nervous system of arachidonate\ a metabolic substrate and lipid mediator rapidly incorporated into microcapillary and brain lipids[ The data also suggested that ] "i# reactive oxyradicals were moderately generated during the early phase of ischemic!reperfusion process in the rat^"ii# after reperfusion\ in vitro susceptibility of di}erent brain regions to iron!induced peroxidation was highest in the hippocampus and lowest in the cortex and striatum^"iii# membrane phospholipid repair mechanisms were activated at the same time[ Þ 0887 ISDN[ Published by Elsevier Science Ltd Key words] Ischemia!reperfusion\ cardiac arrest\ arachidonic acid\ blood!brain barrier\ phospholipids\ retina\ acyltransferase\ peroxidation[ Corresponding author ] Tel[ ] 9928 8422 5889^fax ] 9928 8422 2195^E!mail ] malberÝmbox[unict[it 092 J[ Strosznajder et al[ 093
The authors studied the penetration of 14C-labelled methisoprinol into ocular tissues (cornea, aq... more The authors studied the penetration of 14C-labelled methisoprinol into ocular tissues (cornea, aqueous humour and iris) in rabbits, in which herpetic keratitis had been experimentally induced. It has been demonstrated that the methisoprinol crosses the corneal barrier. The maximum concentration of the drug in the tissues examined was measured 30 min after the instillation of the drug into the conjunctival
The permeability-surface area product (PS) of [1-14C]docosahexaenoate and [1-14C]palmitate at the... more The permeability-surface area product (PS) of [1-14C]docosahexaenoate and [1-14C]palmitate at the blood-retina (BRB) and blood-brain barrier (BBB) was determined after in situ brain perfusion in Sprague-Dawley rats. The intracarotid injection procedure involved continuous infusion of albumin-bound fatty acids for up to 20 s. In the retina, and visual, parietal and frontal cortex, there was a significant decrease in mean PSs for docosahexaenoate compared to the palmitate group. For optic nerve and tract, superior colliculus, lateral geniculate, striatum, hippocampus and olfactory bulb, the comparison of PS values between the two fatty acid-injected groups of animals did not reveal any difference. It is suggested that the lower docosahexaenoate transport, compared to 16:0, across microvascular endothelium of the retina and other cortical regions might help explain the highest availability and selective retention of the essential 22:6(n-3) fatty acid in these nervous system structures.
The blood-retina and blood-brain transport of fatty acids was studied in control and lipid hydrop... more The blood-retina and blood-brain transport of fatty acids was studied in control and lipid hydroperoxide-treated rats by measuring the permeability-surface area product (PS) to [1-14C]palmitate. An in situ carotid perfusion method was used. PS values were evaluated: (1) just after intracarotid injection of hydroperoxides; or (2) after a short-term systemic treatment for 1 week with sonicated emulsion of phospholipids-linoleate peroxidized mixture. Compared with saline-treated rats, PS remarkably decreased in the retina and most brain regions studied after acute, arterial injection of hydroperoxide preparations. On the contrary, the transport index significantly increased in the retina and almost all the brain areas after 7 days i.v. treatment with hydroperoxide emulsion. It is suggested that hydroperoxides acutely administered before transport radiotracer brought about a reinforcement of microvasculature junctional area or hampered substrate diffusion across endothelial membrane. On the other hand, upon short-term i.v. administration, hydroperoxides presumably triggered a lipid structure derangement of endothelial cell membranes and zonulae occludens due to their local accumulation and/or high capability of generating oxygen-free radicals.
Phospholipase A2 and acyltransferase were assayed and characterized in pure axoplasm and neural t... more Phospholipase A2 and acyltransferase were assayed and characterized in pure axoplasm and neural tissues of squid. Intracellular phospholipase A2 activity was highest in giant fiber lobe and axoplasm, followed by homogenates from retinal fibers, optic lobe and fin nerve. In most preparations, exogenous calcium (5 mM) caused a slight stimulation of activity. EGTA (2 mM) was somewhat inhibitory, indicating that low levels of endogenous calcium may be required for optimum activity. Phospholipase A2 was inhibited by 0.1 mM p-bromophenacylbromide, and was completely inactivated following heating. The level of acylCoA: lysophosphatidylcholine acyltransferase activity was higher in axoplasm and giant fiber lobe than in other neural tissues of the squid. Km (apparent) and Vmax (apparent) for oleoyl-CoA and lysophosphatidylcholine were quite similar for axoplasm and giant fiber lobe enzyme preparations. Acyltransferase activity was inactivated by heat treatment, and greatly inhibited by 0.2 mM p-chloromercuribenzoate, and to a lesser extent by 20 mM N-ethylmaleimide. Phospholipase A2 activity was present in fractions enriched in axolemmal membranes (separated from squid retinal fibers and garfish olfactory nerve) from both tissues, and it was also highly concentrated in vesicles derived from squid axoplasm. In all three preparations, phospholipase A2 activity was stimulated by Ca++ (5 mM) and inhibited by EGTA (2 mM). In addition, axoplasmic cytosol (114,000 g supernatant) retained a substantial portion of a Ca(++)-independent phospholipase A2, active in the presence of 2 mM EGTA. Acyltransferase activity was present at high content in both axolemma membrane rich fractions, and among subaxoplasmic fractions and axoplasmic vesicles.
The effect of phospholipid peroxidatlon on the acylation of lysoPtdCho (lysophosphatidylcholine) ... more The effect of phospholipid peroxidatlon on the acylation of lysoPtdCho (lysophosphatidylcholine) by axolemma-enriched fraction prepared from rat brain stem was investigated. After two types of peroxidative treatments, the hi rllrO induction ofmalondialdehyde and conjugated dienes formation m axolemmal membranes correlated to a shift in the ratio of saturated/unsaturated fatty acids. By using an Fe 2+ (20/tMJ-ascorbate (0.25 mM) peroxidation system, the residual acyltransferase activity was 55% of the initial one. No change in Km value for either oleoyl-CoA or lysoPtdCho was found, whereas a loss of 24% m V.,~, was observed. After 5 rain preincubation with 150 mM t-BuOOH, 70% inactivation of the acylation reaction was observed. A near suppression of enzyme activity was reached with 400 raM. The apparent Km for oleoyl-CoA decreased sharply (from 6.6 /~M in control preparations to 4.1 /~M in t-BuOOH-treated membranes), indicating a 2-fold increase in the enzymatic affinity for this substrate. The apparent Km for lysoPtdCho increased markedly (from 1.56/~M in the control preparations to 5.88/~M in t-BuOOH-treated membranes) whereas a decrease of V,,j, (from 1.65 to 0.80 nmol/min/mg protein) for the same substrate was observed, Significant enzyme inactivation (loss of 60% of initial activity) was seen when l0/~mol of photooxidlzed phospboliplds were preincubated with axolemmal membranes. Significant dose-dependent enzyme inactivation was brought about by addition of 10-60 /2mol of peroxldlzed PtdEtn/100/~g axolemmal protein. The percent enzyme inhibition by peroxidized PtdCho at equivalent amounts was lower than that by PtdEtn. Linolelc acid hydroperoxides, exogenously added or generated in situ, had a concentration-dependent effect, promoting a marked inhibition of acyltransferase activity.
The effect of CDP-choline on the in vivo incorporation of labeled precursors into DNA, RNA, and p... more The effect of CDP-choline on the in vivo incorporation of labeled precursors into DNA, RNA, and proteins in cerebral hemispheres, cerebellum, and brainstem of guinea pigs after hypoxic treatment was studied. The labeling of macromolecules extracted from the various subcellular fractions of these brain regions was also determined. Hypoxic treatment affected macromolecular labeling to a different extent in the three brain regions examined. CDP-choline treatment was not able to reverse the effect of hypoxia on DNA labeling, but it was able to remove the effect of hypoxia on RNA and protein labeling. The action of CDP-choline was particularly evident on the labeling of RNA in nuclei and mitochondria of the cerebellum and on the labeling of proteins in microsomes of the three brain regions examined.
In the M. tuberculosis H37Rv and in the human tubercular strains isolated from patients, the loca... more In the M. tuberculosis H37Rv and in the human tubercular strains isolated from patients, the localization of genetic determinants of drug-resistance to antitubercular chemotherapeutic drugs in current use was studied. Data obtained through the treatment of the resistanct strains with acridine dyes and ethidium bromide, and the analysis of irreversible elimination of resistance markers support the hypothesis of an extrachromosomal locus for the p-aminosalicylic acid (PAS)-resistance and confirm a chromosomal mutation for the isoniazid (INH), ethambutol (EM), rifampicin (R/AMP)-resistances, in all the levels reached in training or selected in wild strains. In the PAS-revertants recovered after treatment with mutagenic agents, a loss by degrees of resistance levels was observed. In a mycobacterial strain biresistant to PAS and streptomycin (Sm) the Authors were able to find a loss of the mono-resistance to Sm only. The significance of these results is discussed in terms of plasmid (s) ...
In the present report evaluation of the possible metabolic changes in partially revertants of M. ... more In the present report evaluation of the possible metabolic changes in partially revertants of M. tuberculosis var. hominis, reisolated from strains at high levels of drug-resistance after treatment with mutagenic agents, was reported. Based on the data presented here, it must be concluded that no significant biological and biochemical differences in mycobacterial cells revertant from high mutants mono-resistant to four aminoglycosides (Sm, Kana, Vio, Neo) and p-aminonasalicylic acid (PAS) are to be found.
Incorporation of labelled precursors into neutral lipids and phospholipids of hypertrophied guine... more Incorporation of labelled precursors into neutral lipids and phospholipids of hypertrophied guinea-pig cardiac ventricles during normobaric hypoxia (breathing gas mixture of N2: O2, 9: 91%) was studied. The lipids of the heart were isotopically labelled in vivo with [1-14C] palmitate and [2-3H] glycerol, and, after a period of 2 hours, the incorporation of the two injected precursors into mitochondrial and microsomal fractions was determined. Eighty hours after the onset of the hypoxic treatment, the specific activities of isolated lipids showed a more elevated incorporation into lipid classes of hypoxic right and left ventricles with respect to that of the control. For both precursors, the percent increase of incorporation into microsomal and mitochondrial neutral lipids was higher than into phospholipids. In the microsomal fraction the increase of 14C-radioactivity incorporation was more pronounced than 3H-incorporation. 3H/14C incorporation ratio appeared decreased in hypoxic ven...
The effect of simple and mixed copper(II) complexes of L-tryptophan (trp) and L-phenylalanine (ph... more The effect of simple and mixed copper(II) complexes of L-tryptophan (trp) and L-phenylalanine (phe) on the gastric acid secretion was investigated in Shay rats. Graded doses (from 15 to 75 mg/kg) of [Cu(trp)2(H2O)], [Cu(phe)2(H2O)] and [Cu(trp)(phe)(H2O)], administered i.g., caused a progressive inhibition of gastric acid secretion. The antisecretory activity of the mixed complex, [Cu(trp)(phe)(H2O)], was significantly greater (ID50 = 33 +/- 3 mg/kg) than that of the simple complexes [Cu(trp)2(H2O)] (ID50 = 48 +/- 3 mg/kg) and [Cu(phe)2(H2O)] (ID50 = 43 +/- 3 mg/kg). At the experimental conditions of intragastric pH, the different biological activities were directly related to the percentage of neutral species present in solution as determined by means of potentiometric measurements (at 37 degrees, I = 0.15 mol dm-3 in NaClO4). A possible mechanism of action of the investigated compounds is discussed.
The genotype distribution of two gene polymorphisms, previously associated with peripheral artery... more The genotype distribution of two gene polymorphisms, previously associated with peripheral artery disease (PAD), has been evaluated in a population of diabetic (DPAD) and non-diabetic (NDPAD) patients affected by symptomatic PAD (stages II-IV). A decreased frequency of the AA genotype of rs5498 (ICAM-1) was observed in the PAD subjects compared to controls but this result did not reach statistical significance (p=0.06 by chi-squared test). On the contrary, a significant increase in the frequency of the GG homozygous genotype of rs248793 (SRD5A1) was observed in the PAD patient group in comparison to controls (p=0.01). These data confirm that the GG genotype of rs248793 in the SRD5A1 gene is significantly associated with symptomatic PAD and show a trend towards a stronger association with the non-diabetic status.
We describe the inhibitory effect of A beta (25-35) fragment of amyloid-beta peptide and bradykin... more We describe the inhibitory effect of A beta (25-35) fragment of amyloid-beta peptide and bradykinin (BK) on phosphatidylcholine (PtdCho) metabolism in immortalized rat brain GP8.39 endothelial cells (EC). Cultures were incubated either with A beta for 24-48 h, or with BK for 30 min-4 h. The peroxidation indices (malondialdehyde, conjugated dienes) and lactate dehydrogenase (LDH) release significantly increased after A beta peptide (10-50 microM) treatment. The BK (10 microM) stimulation of cells brought about an increase in conjugated dienes and LDH release only after 4 h. Following 24 h treatment with 50 microM A beta peptide, the [Me-3H]choline incorporation into PtdCho strongly decreased while the [3H]choline release increased, indicating PtdCho hydrolysis. The effect was most likely due to peptide prooxidant effect. After 4 h preincubation with BK, the [Me-3H]choline incorporation into PtdCho strongly decreased, but no significant [3H]choline release was found. Following long-te...
A brief description of the importance of axonal transport for nerve cell metabolism, with a discu... more A brief description of the importance of axonal transport for nerve cell metabolism, with a discussion of some special features affecting the retina and optic nerve. A connection is made between this transport and a variety of eye diseases in the light of recent publications. In particular, the role played by axonal transport in the course of diseases of the optic nerve (papilledema), elevation of IOP and retinopathies with vascular origins is summarized.
Molecular and chemical neuropathology / sponsored by the International Society for Neurochemistry and the World Federation of Neurology and research groups on neurochemistry and cerebrospinal fluid, 1989
In the present work, the hypothesis that the increased rapid intracellular transport of newly-syn... more In the present work, the hypothesis that the increased rapid intracellular transport of newly-synthesized material along the axons of a regenerating system is sustained by an alteration of the transport of proteolipid complexes through subcellular compartments of a neuronal cell body was tested by a biochemical methodology. The motoneurons of spinal cord ventral horn, 4 wk after unilateral lesion (crush) of cervico-thoracic nerves of the rabbit at the level of brachial plexus, were chosen as the model system of regeneration. A time-staggered procedure of in vivo and in vitro double labeling with metabolic precursors, such as [3H]-choline, [14C]-choline, [3H]-fucose, and [14C]-fucose, was used. Subcellular fractions (RER, SER, Golgi apparatus, and plasma membranes) of ventral horn tissue, taken from spinal cord hemisections (regenerating and contralateral side), were further isolated. Twenty-eight days after axotomy, we did not observe any change of intracellular transport kinetics (...
We examined the effects of age on RNA and lipid formation by whole retina and optic nerve in vitr... more We examined the effects of age on RNA and lipid formation by whole retina and optic nerve in vitro. Male Wistar rats, aged 4, 12, and 24 mo, were used. From the results obtained the following conclusions may be drawn: 1. In assaying the lipid biosynthesis during aging, a striking difference between the retina and optic nerve clearly emerged; 2. In isolated retina, [3H]uridine incorporation into RNA was relatively constant at the three ages, whereas both [14C]palmitate and [3H]choline incorporation into lipids showed a substantial increase in rats at 24 mo of age compared with those at 4 mo; 3. In contrast, in the optic nerve of the oldest rats, compared with the youngest, a significant decrease of [14C]acetate and [14C]palmitate incorporation into acylglycerols, cerebrosides, and phospholipids was found. Each fatty acid precursor label was incorporated to a proportion that reflected the typical acyl group composition of individual lipids; 4. Following labeling of the optic nerve wit...
The synthesis and chemical behaviour of N-(benzothiazolyl-2-carbonyl)-N-1-(2-thiazolyl)hydrazines... more The synthesis and chemical behaviour of N-(benzothiazolyl-2-carbonyl)-N-1-(2-thiazolyl)hydrazines is described. All the products were screened in vitro for antimicrobial activity. Some of them were found to give positive results.
International Journal of Developmental Neuroscience, 1998
The permeability!surface area product "PS# of ð0! 03 CŁarachidonate at the blood!retina and blood... more The permeability!surface area product "PS# of ð0! 03 CŁarachidonate at the blood!retina and blood! brain barrier was determined by short carotid perfusion in young Wistar rats 0 or 5 h after recovery period following complete cerebral ischemia induced by temporary cardiac arrest[ For the retina and structures of visual system\ hypothalamus and olfactory bulb there was no signi_cant di}erence over sham!operated rats among mean PSs[ For cortex\ hippocampus and striatum\ signi_cant increases were found at both time intervals of recovery after cardiac arrest[ The ischemia!reperfusion model was characterized by a signi_cant increase in tissue conjugated diene in the hippocampus and microsomal lysophosphatidylcholine acyltransferase activity in the cortex[ Consistent with these _ndings\ we also show ultrastructural evidence mainly represented by partial opening of interendothelial junctions and mild signs of tissue edema in surrounding neuropil\ suggesting barrier leakiness predominantly in the cortex\ hippocampus and striatum but almost absent in the retina microvessels[ Our results indicate that ischemia!reperfusion does a}ect in~ux through blood!brain barrier into regional structures of rat central nervous system of arachidonate\ a metabolic substrate and lipid mediator rapidly incorporated into microcapillary and brain lipids[ The data also suggested that ] "i# reactive oxyradicals were moderately generated during the early phase of ischemic!reperfusion process in the rat^"ii# after reperfusion\ in vitro susceptibility of di}erent brain regions to iron!induced peroxidation was highest in the hippocampus and lowest in the cortex and striatum^"iii# membrane phospholipid repair mechanisms were activated at the same time[ Þ 0887 ISDN[ Published by Elsevier Science Ltd Key words] Ischemia!reperfusion\ cardiac arrest\ arachidonic acid\ blood!brain barrier\ phospholipids\ retina\ acyltransferase\ peroxidation[ Corresponding author ] Tel[ ] 9928 8422 5889^fax ] 9928 8422 2195^E!mail ] malberÝmbox[unict[it 092 J[ Strosznajder et al[ 093
The authors studied the penetration of 14C-labelled methisoprinol into ocular tissues (cornea, aq... more The authors studied the penetration of 14C-labelled methisoprinol into ocular tissues (cornea, aqueous humour and iris) in rabbits, in which herpetic keratitis had been experimentally induced. It has been demonstrated that the methisoprinol crosses the corneal barrier. The maximum concentration of the drug in the tissues examined was measured 30 min after the instillation of the drug into the conjunctival
The permeability-surface area product (PS) of [1-14C]docosahexaenoate and [1-14C]palmitate at the... more The permeability-surface area product (PS) of [1-14C]docosahexaenoate and [1-14C]palmitate at the blood-retina (BRB) and blood-brain barrier (BBB) was determined after in situ brain perfusion in Sprague-Dawley rats. The intracarotid injection procedure involved continuous infusion of albumin-bound fatty acids for up to 20 s. In the retina, and visual, parietal and frontal cortex, there was a significant decrease in mean PSs for docosahexaenoate compared to the palmitate group. For optic nerve and tract, superior colliculus, lateral geniculate, striatum, hippocampus and olfactory bulb, the comparison of PS values between the two fatty acid-injected groups of animals did not reveal any difference. It is suggested that the lower docosahexaenoate transport, compared to 16:0, across microvascular endothelium of the retina and other cortical regions might help explain the highest availability and selective retention of the essential 22:6(n-3) fatty acid in these nervous system structures.
The blood-retina and blood-brain transport of fatty acids was studied in control and lipid hydrop... more The blood-retina and blood-brain transport of fatty acids was studied in control and lipid hydroperoxide-treated rats by measuring the permeability-surface area product (PS) to [1-14C]palmitate. An in situ carotid perfusion method was used. PS values were evaluated: (1) just after intracarotid injection of hydroperoxides; or (2) after a short-term systemic treatment for 1 week with sonicated emulsion of phospholipids-linoleate peroxidized mixture. Compared with saline-treated rats, PS remarkably decreased in the retina and most brain regions studied after acute, arterial injection of hydroperoxide preparations. On the contrary, the transport index significantly increased in the retina and almost all the brain areas after 7 days i.v. treatment with hydroperoxide emulsion. It is suggested that hydroperoxides acutely administered before transport radiotracer brought about a reinforcement of microvasculature junctional area or hampered substrate diffusion across endothelial membrane. On the other hand, upon short-term i.v. administration, hydroperoxides presumably triggered a lipid structure derangement of endothelial cell membranes and zonulae occludens due to their local accumulation and/or high capability of generating oxygen-free radicals.
Phospholipase A2 and acyltransferase were assayed and characterized in pure axoplasm and neural t... more Phospholipase A2 and acyltransferase were assayed and characterized in pure axoplasm and neural tissues of squid. Intracellular phospholipase A2 activity was highest in giant fiber lobe and axoplasm, followed by homogenates from retinal fibers, optic lobe and fin nerve. In most preparations, exogenous calcium (5 mM) caused a slight stimulation of activity. EGTA (2 mM) was somewhat inhibitory, indicating that low levels of endogenous calcium may be required for optimum activity. Phospholipase A2 was inhibited by 0.1 mM p-bromophenacylbromide, and was completely inactivated following heating. The level of acylCoA: lysophosphatidylcholine acyltransferase activity was higher in axoplasm and giant fiber lobe than in other neural tissues of the squid. Km (apparent) and Vmax (apparent) for oleoyl-CoA and lysophosphatidylcholine were quite similar for axoplasm and giant fiber lobe enzyme preparations. Acyltransferase activity was inactivated by heat treatment, and greatly inhibited by 0.2 mM p-chloromercuribenzoate, and to a lesser extent by 20 mM N-ethylmaleimide. Phospholipase A2 activity was present in fractions enriched in axolemmal membranes (separated from squid retinal fibers and garfish olfactory nerve) from both tissues, and it was also highly concentrated in vesicles derived from squid axoplasm. In all three preparations, phospholipase A2 activity was stimulated by Ca++ (5 mM) and inhibited by EGTA (2 mM). In addition, axoplasmic cytosol (114,000 g supernatant) retained a substantial portion of a Ca(++)-independent phospholipase A2, active in the presence of 2 mM EGTA. Acyltransferase activity was present at high content in both axolemma membrane rich fractions, and among subaxoplasmic fractions and axoplasmic vesicles.
The effect of phospholipid peroxidatlon on the acylation of lysoPtdCho (lysophosphatidylcholine) ... more The effect of phospholipid peroxidatlon on the acylation of lysoPtdCho (lysophosphatidylcholine) by axolemma-enriched fraction prepared from rat brain stem was investigated. After two types of peroxidative treatments, the hi rllrO induction ofmalondialdehyde and conjugated dienes formation m axolemmal membranes correlated to a shift in the ratio of saturated/unsaturated fatty acids. By using an Fe 2+ (20/tMJ-ascorbate (0.25 mM) peroxidation system, the residual acyltransferase activity was 55% of the initial one. No change in Km value for either oleoyl-CoA or lysoPtdCho was found, whereas a loss of 24% m V.,~, was observed. After 5 rain preincubation with 150 mM t-BuOOH, 70% inactivation of the acylation reaction was observed. A near suppression of enzyme activity was reached with 400 raM. The apparent Km for oleoyl-CoA decreased sharply (from 6.6 /~M in control preparations to 4.1 /~M in t-BuOOH-treated membranes), indicating a 2-fold increase in the enzymatic affinity for this substrate. The apparent Km for lysoPtdCho increased markedly (from 1.56/~M in the control preparations to 5.88/~M in t-BuOOH-treated membranes) whereas a decrease of V,,j, (from 1.65 to 0.80 nmol/min/mg protein) for the same substrate was observed, Significant enzyme inactivation (loss of 60% of initial activity) was seen when l0/~mol of photooxidlzed phospboliplds were preincubated with axolemmal membranes. Significant dose-dependent enzyme inactivation was brought about by addition of 10-60 /2mol of peroxldlzed PtdEtn/100/~g axolemmal protein. The percent enzyme inhibition by peroxidized PtdCho at equivalent amounts was lower than that by PtdEtn. Linolelc acid hydroperoxides, exogenously added or generated in situ, had a concentration-dependent effect, promoting a marked inhibition of acyltransferase activity.
The effect of CDP-choline on the in vivo incorporation of labeled precursors into DNA, RNA, and p... more The effect of CDP-choline on the in vivo incorporation of labeled precursors into DNA, RNA, and proteins in cerebral hemispheres, cerebellum, and brainstem of guinea pigs after hypoxic treatment was studied. The labeling of macromolecules extracted from the various subcellular fractions of these brain regions was also determined. Hypoxic treatment affected macromolecular labeling to a different extent in the three brain regions examined. CDP-choline treatment was not able to reverse the effect of hypoxia on DNA labeling, but it was able to remove the effect of hypoxia on RNA and protein labeling. The action of CDP-choline was particularly evident on the labeling of RNA in nuclei and mitochondria of the cerebellum and on the labeling of proteins in microsomes of the three brain regions examined.
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Papers by M. Alberghina