Impact of SARS-CoV-2 Pandemic and Lockdown on the HRSV Circulation: Experience of Three Spoke Hospitals in Northern Italy

The SARS-CoV-2 Pandemic affected the global epidemiology of respiratory infections, including Human Respiratory Syncytial Virus (HRSV), thanks to state governments' implementation of mitigation strategies, like the promotion of face masks and lockdowns. However, after the Pandemic, the dramatic resurge of these diseases was reported worldwide. Our retrospective study, involving three Spoke Pediatric Departments, includes all the infants under one year of age hospitalized for HRSV bronchiolitis in a period before the Pandemic period (2017-2020), during the SARS-CoV-2 Pandemic (2020-2021), and after the Pandemic (2021-2023). The primary aim was to analyze the temporal trend of HRSV in these three periods. Then, the clinical and epidemiological characteristics were analyzed to highlight the clinical differences in the affected patients, in the severity of the infections, and in the short-term outcomes. Ultimately, we analyzed the HRSV prevalence in the global bronchiolitis hospitalization over the reported periods. Overall, we included 237 patients. Before the Pandemic, the peak was recorded in January and February, while after the Pandemic, the peak was in November and December. A higher prevalence of HRSV was demonstrated after the Pandemic compared to the period before the Pandemic; overall, no difference in severity was reported. In conclusion, an increase in HRSV cases after the Pandemic has been demonstrated with an anticipated peak, while no differences were recorded in severity.

Management of Acute Bronchiolitis in Spoke Hospitals in Northern Italy: Analysis and Outcome

Bronchiolitis is an acute viral infection of the lower respiratory tract that affects infants and young children. Respiratory syncytial virus (RSV) is the most common causative agent; however, other viruses can be involved in this disease. We retrospectively reviewed the clinical features of infants aged less than 12 months hospitalized for acute bronchiolitis in our Pediatric Units of Chivasso, Cirié, and Ivrea in Piedmont, Northern Italy, over two consecutive bronchiolitis seasons (September 2021-March 2022 and September 2022-March 2023). Patient-, disease-, and treatment-related variables were analyzed. The probability of therapeutic success (discharge home) was 96% for all patients (93% for RSV vs. 98% for non-RSV patients, p > 0.05). Among 192 patients, 42 infants (22%) underwent high-flow oxygen support (HFNC), and only 8 (4%) needed to be transferred to our hub referral hospital. Factors associated with hub hospital transfer were the age under 1 month and the failure of HFNC. The wide and increasing use of HFNC in pediatric inpatients improved the management of bronchiolitis in Spoke hospitals, reducing transfer to a hub hospital provided with Intensive Care Units.

ELOVL5 mutations cause spinocerebellar ataxia 38

Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal-dominant neurodegenerative disorders involving the cerebellum and 23 different genes. We mapped SCA38 to a 56 Mb region on chromosome 6p in a SCA-affected Italian family by whole-genome linkage analysis. Targeted resequencing identified a single missense mutation (c.689G>T [p.Gly230Val]) in ELOVL5. Mutation screening of 456 independent SCA-affected individuals identified the same mutation in two further unrelated Italian families. Haplotyping showed that at least two of the three families shared a common ancestor. One further missense variant (c.214C>G [p.Leu72Val]) was found in a French family. Both missense changes affect conserved amino acids, are predicted to be damaging by multiple bioinformatics tools, and were not identified in ethnically matched controls or within variant databases. ELOVL5 encodes an elongase involved in the synthesis of polyunsaturated fatty acids of the ω3 and ω6 series. Arachidonic acid and docosahexaenoic acid, two final products of the enzyme, were reduced in the serum of affected individuals. Immunohistochemistry on control mice and human brain demonstrated high levels in Purkinje cells. In transfection experiments, subcellular localization of altered ELOVL5 showed a perinuclear distribution with a signal increase in the Golgi compartment, whereas the wild-type showed a widespread signal in the endoplasmic reticulum. SCA38 and SCA34 are examples of SCAs due to mutations in elongase-encoding genes, emphasizing the importance of fatty-acid metabolism in neurological diseases.

High glucose and advanced glycation end products induce phospholipid hydrolysis and phospholipid enzyme inhibition in bovine retinal pericytes

In the present study, we investigated the possible role of oxidative stress and the modulation of phospholipid turnover in two related models of pericyte injury, i.e., treatment with high glucose or advanced glycation end products (AGEs). Growing microcapillary pericytes from bovine retinas in culture were incubated, for 3 weeks, with 20-50 mM glucose or 2-20 microM AGEs, and peroxidation parameters (malondialdehyde, conjugated diene, hydroperoxide, glutathione (GSH) levels and lactate dehydrogenase (LDH) release) were evaluated. Arachidonate (AA) and choline release from membrane phospholipids was determined in pericytes prelabeled with [1-(14)C]arachidonate and [Me-(3)H]choline, respectively, and stimulated with elevated glucose or AGEs for 30 min or 2 h. [1-(14)C]arachidonate and [Me-(3)H]choline incorporation into phospholipids, for 2 h and 3 h respectively, was also studied in conditioned and serum-starved cultures. Finally, lysates of treated and control cells were assayed for cytosolic phospholipase A(2) (cPLA(2)), acyl-CoA:1-acyl-sn-glycero-3-phosphocholine O-acyltransferase (AT), CTP:phosphocholine cytidylyltransferase (CT) and microsomal choline phosphotransferase (CPT) enzyme activities. We found that high glucose and AGEs caused neither significant production of reactive oxygen species nor cell toxicity or death, unlike other cell types. Both agents had no significant effect on the cellular ultrastructure, evaluated by light and electron microscopy, AA incorporation and release, cytosolic phospholipase A(2) (cPLA(2)) and AT activities. On the contrary, choline incorporation into phosphatidylcholine, CT and CPT activities were significantly reduced either by 50 mM glucose or 20 microM AGEs. Simultaneously, [Me-(3)H]choline release was significantly stimulated by both agents. We conclude that prolonged treatments with high glucose or AGEs are not able to induce oxidative injury in bovine retinal capillary pericytes. Nevertheless, they do induce phospholipid hydrolysis and phospholipid enzyme activity inhibition.

t-Butyl hydroperoxide and oxidized low density lipoprotein enhance phospholipid hydrolysis in lipopolysaccharide-stimulated retinal pericytes

Free radicals induced by organic peroxides or oxidized low density lipoprotein (oxLDL) play a critical role in the development of atherosclerosis. In investigating this process, and the concomitant inflammatory response, the role of pericytes, cells supporting the endothelial ones in blood vessels, has received little attention. In this study we tested the hypothesis that tert-butyl hydroperoxide (t-BuOOH) and oxLDL, administered in sublethal doses to the culture medium of retinal pericytes, function as prooxidant signals to increase the stimulation of the peroxidation process induced by lipopolysaccharide (LPS). Confluent cell monolayers were exposed to t-BuOOH (25-400 microM), native LDL or oxLDL (3.4-340 nmol hydroperoxides/mg protein, 1-100 micro). LPS (1 microg/ml), t-BuOOH (200 microM), and oxLDL (100 microM), but not native LDL, incubated for 24 h with cells, markedly increased lipid peroxidation, cytosolic phospholipase A2 (cPLA2) activity and arachidonic acid (AA) release in a time- and dose-dependent manner. AACOCF(3), a potent cPLA2 inhibitor, and the antioxidant alpha-tocopherol strongly inhibited the prooxidant-stimulated AA release. Long-term exposure to maximal concentrations of t-BuOOH (400 microM) or oxLDL (100 microM) had a sharp cytotoxic effect on the cells, described by morphological and biochemical indices. The presence of t-BuOOH or oxLDL at the same time, synergistically increased phospholipid hydrolysis induced by LPS alone. 400 microM t-BuOOH or 100 microM oxLDL had no significant effect on the stimulation of an apoptosis process estimated by DNA laddering and light and electron microscopy. The results indicate that (i) pericytes may be the target of extensive oxidative damage; (ii) activation of cPLA2 mediates AA liberation; (iii) as long-term regulatory signals, organic peroxide and specific constituents of oxLDL increase the pericyte ability to degrade membrane phospholipids mediated by LPS which was used, in the present study, to simulate in vitro an inflammatory burst in the retinal capillaries.

Antioxidant activity and protective effect on DNA cleavage of extracts from Cistus incanus L. and Cistus monspeliensis L

The genus Cistus includes many typical species of Mediterranean flora; Cistus species are used as antidiarrhetics, as general remedies for treatment of various skin diseases in folk medicine and as anti-inflammatory agents. These species contain flavonoids that are considered to be chain-breaking antioxidants. In this work, we have investigated the effects of crude aqueous extracts from Cistus incanus and Cistus monspeliensis on DNA cleavage and their free-radical scavenging capacity. In addition, their effect on lipid peroxidation in rat liver microsomes was evaluated. These extracts showed a protective effect on DNA cleavage and a dose-dependent free-radical scavenging capacity; Cistus monspeliensis was more active than Cistus incanus; these results were confirmed by a significant inhibition of lipid peroxidation in rat liver microsomes. The experimental evidence, therefore, suggests that because of their antioxidant activity these extracts may offer excellent photoprotection for skin and may be useful in the treatment of human diseases where oxidative stress plays a key role.

Fibroblast growth factor-2 and transforming growth factor-beta1 immunostaining in rat brain after cerebral postischemic reperfusion

Several trophic factors are known to regulate the survival and growth of neurons in brain and peripheral tissues. Several findings suggest that basic fibroblast growth factor-2 (FGF-2) plays an important role in the "self-repair" responses that follow injuries such as trauma and brain ischemia and that FGF-2 contributes to the repair of damaged tissue. Transforming growth factor-beta (TGF-beta) is a potent growth-regulatory protein secreted by virtually all cells. In the present study, we used immunohistochemical techniques to investigate whether FGF-2 and TGF-beta1 participate in the healing of damaged tissue following partial brain ischemia. The profile of the observed immunoreactivities indicated that TGF-beta1 and FGF-2 release varies between the different cerebral areas subjected to ischemic insult. Moreover, the sectorial heterogeneity of immunocytochemical response suggests that, during postischemic reperfusion, neuronal recovery may be due not only to neuron-glia interaction but also to neurochemical conditions involving inhibitory interneurons.

Long-term ethanol administration enhances age-dependent modulation of redox state in central and peripheral organs of rat: protection by metadoxine

Evidence is accumulating that intermediates of oxygen reduction may be associated with the development of alcoholic disease. In addition, free radical-induced perturbation of the oxidant/antioxidant balance in cells is widely recognized as the main causative factor of age-related disorders. In the present work, we investigated the effects of 25 months of ethanol consumption on the antioxidant defense system in different organs of rat in comparison with normal aging, in the absence and presence of treatment with metadoxine, an ion pair composed of pirrolidone carboxylate and pyridoxine. We demonstrate that aged rats underwent a significant perturbation of the antioxidant defense system, as indicated by depletion of reduced glutathione (GSH) content, and increases in oxidized GSH and free radical-induced luminescence associated with a decrease of GSH reductase and an increase of GSH transferase activities. These modifications, observed particularly in the liver and brain with respect to other organs, were enhanced by long-term alcohol exposure, and interestingly, significantly reduced after metadoxine supplementation. Our results indicate that increased GSH transferase activity and decreased GSH reductase activity, followed by thiol depletion, are important factors sustaining a pathogenic role for oxidative stress in aging and in all situations where age-correlated changes occur. Administration of metadoxine greatly reduces these metabolic abnormalities. This evidence supports the pharmacological potential of metadoxine in the management of alcoholic disturbances.

Long-term ethanol administration enhances urinary ultraweak luminescence and age-dependent modulation of redox in central and peripheral organs of the rat

Numerous experimental evidence sustains a pathogenic role for oxidative stress in aging. Acute and chronic ethanol metabolism is also known to be associated with oxidative perturbation of cellular oxidant/antioxidant balance. In the present work we investigated the effects of 25 months of ethanol consumption on the antioxidant defense system in different organs of rats, in comparison with normal and aged animals. We show that aged rats underwent a significant perturbation of the antioxidant defense system, as indicated by depletion of reduced glutathione content, increases in oxidized glutathione and free radical-induced urinary luminescence associated with a decrease of glutathione reductase and increase of glutathione transferase activities. These modifications, observed particularly in the liver and brain, were enhanced by long-term alcohol exposure. Our results indicate that increased glutathione transferase activity and decreased glutathione reductase activity, followed by thiol depletion, are important factors sustaining a pathogenic role for oxidative stress in aging and in all situations where age-correlated changes occur. They also reinforce the oxidative potential of toxic compounds, such as ethanol intoxication.

Regulation of cytochrome c oxidase and FoF1-ATPase subunits expression in rat brain during aging

In the present study we analyzed the age-dependent changes of mRNA levels for cytochrome c oxidase and FoF1-ATP synthase subunits in rat cerebral cortex and cerebellum. To establish whether the regulation of expression is transcriptional or post-transcriptional, the results were compared to those related to protein subunits levels, of the same enzymatic complexes, previously observed. The different patterns of age-related changes of mRNA subunits, in particular the lower increments, compared with those related to protein subunits, indicate that post-transcriptional mechanisms of regulation might be involved in the coordinated expression of the various subunits of each complex. Northern blotting analyses of RNA from the cerebellum of rats at the various ages, showed also differences in age-dependent patterns of transcription between cerebral cortex and cerebellum. Moreover, the major age-dependent changes of mitochondrial-encoded subunits, compared with the nuclear-encoded ones, previously observed at proteins level, occur also during transcription.

Cysteine-induced enhancement of lipid peroxidation in substantia nigra: comparative effect with exogenous administration of reduced glutathione

It is generally accepted that reactive oxygen species have a major role in the mediation of cell damage and that free sulphydryl (SH) groups are vital in cellular defence against endogenous or exogenous oxidants. Modification of cellular oxidant/antioxidant balance has been involved in the neuropathogenesis of several diseases, e.g., stroke, Parkinson's disease, Alzheimer's disease and physiological ageing. An increasingly important area of antioxidant defence is based on sulphydryl chemistry, owing to the role of SH groups in the function of macromolecular structures such as enzymes and cellular membranes. Thiols, however, may themselves generate deleterious free radicals, and thionyl radicals, which have been demonstrated to originate in biological systems through enzymatic reactions of different peroxidases, by reacting with molecular oxygen or hydrogen peroxide are able to promote reactions of oxidatives stress. In the present study we provide experimental evidence suggesting a selective effect of cysteine in promoting reactions of oxidative stress in the brain areas of substantia nigra and septum, but not in other areas. In contrast, exogenous administration of reduced glutathione led to a significant decrease of lipoperoxidation in the brain areas of cortex and hippocampus, associated to selective changes in the endogenous pool of thiols.

Changes in endogenous lipoperoxidation and antioxidant enzyme status induced by cysteine in the substantia Nigra

It is generally accepted that reactive oxygen species have a major role in the mediation of cell damage and that free sulfhydryl groups are vital in cellular defence against endogenous or exogenous oxidants. Modification of cellular oxidant/antioxidant balance has been involved in the neuropathogenesis of several diseases, e.g., stroke, Parkinson's disease, Alzheimer's disease and physiological ageing. An increasingly important area of antioxidant defence is based on sulfhydryl chemistry, owing to the role of -SH groups in the function of macromolecular structures such as enzymes and cellular membranes. Thiols, however, may themselves generate deleterious free radicals. In the present study we provide experimental evidence suggesting a selective effect of cysteine in promoting reactions of oxidative stress in the brain areas of substantia nigra and septum, but not in other different areas which were associated with corresponding changes in the activity of antioxidant enzymes.

Changes of mitochondrial cytochrome c oxidase and FoF1 ATP synthase subunits in rat cerebral cortex during aging

The contents of subunits I, II/III, and IV of cytochrome c oxidase and of subunits alpha, beta and gamma of FoF1 ATP synthase in inner mitochondrial membrane proteins purified from cerebral cortex of rat at 2, 6, 12, 18, 24, and 26 months of age were analyzed by western blot. Age-related changes in the content of subunits, either of mitochondrial or nuclear origin, were observed. All the cytochrome c oxidase (COX) subunits examined showed an age-related increase from 2-month-old rats up to 24 months with a decrease at the oldest age (26 months). The same pattern of age-dependent changes was observed for gamma ATP synthase, while the alpha and beta subunits increased progressively up to 26 months.

AMPA-selective glutamate receptor subunits in the rat hippocampus during aging

The levels of mRNAs for the subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptors (GluR-1, -2, -3, -4) in the rat hippocampus during aging were measured by Northern blotting. The distribution of these receptors was also examined at the protein level by immunoblotting using antibodies to GluR-1 and to an epitope common to GluR-2 and GluR-3 (denoted GluR-2/3). During aging a significant decrease of GluR-1 protein, but no change in the corresponding mRNA level, was observed. No differences in the level of GluR-2/3 protein and GluR-2, -3, and -4 mRNAs at the various ages examined (4, 12, and 24 months) were detected. Our results show that AMPA receptors are only slightly influenced by the aging process in the rat hippocampus. The slight decrease in GluR-1 protein content, not accompanied by a parallel decrease in the GluR-1 mRNA level, might be explained by a decreased translational efficiency or an increased protein degradation of the GluR-1 subunit.

Effect of pyrrolidone carboxylate (PCA) and pyridoxine on liver metabolism during chronic ethanol intake in rats

Rats subjected to chronic ethanol intake for a period of 28 days showed significant elevation in blood ethanol levels, a marked decrease in hepatic reduced glutathione (GSH) content and a decrease in liver tryptophan pyrrolase (TPO) activity. A daily intraperitoneal injection of a combined solution of pyrrolidone carboxylate (PCA) and vitamin B6 (pyridoxine hydrochloride) (0.3 mmoles/kg) into ethanol-treated rats resulted in the blood ethanol levels becoming significantly reduced, while the hepatic GSH content and TPO activity were markedly elevated. Our results support the view that PCA and pyridoxine operate to restore the redox imbalance of the hepatocytes caused by chronic alcohol intake.

Effects of metadoxine on cellular formation of fatty acid ethyl esters in ethanol treated rats

Free fatty acids (FFA) and fatty acid ethyl esters (FAEE) were extracted from different organs of rats administered ethanol, which was found to have induced FAEE formation, which reached its highest levels in the heart, followed by kidney, brain and liver; the ethanol administration resulted also in a marked increase of total FFA content, particularly in brain, kidney, heart and liver. Pretreatment of animals with Metadoxine one hour before ethanol administration inhibited significantly both FAEE and FFA accumulation in all organs examined. These effects were concomitant with the decreased levels of ethanol in blood found in alcohol-intoxicated rats pretreated with Metadoxine. Our results point to the role of fatty acid ethyl esters as possible mediators in the production of alcohol-dependent syndromes, especially in organs lacking oxidative pathways. Administration of Metadoxine, through an increment in alcohol metabolism and turnover, greatly reduces this metabolic abnormality, warranting its potential usefulness as a pharmacological tool in alcoholism management.

Effect of CDP-choline treatment on mitochondrial and synaptosomal protein composition in different brain regions during aging

Several age-dependent modifications of inner mitochondrial membrane and synaptosomal plasma membrane proteins from different brain regions of 4-, 12-, 18- and 24-month-old male Wistar rats, were observed. Some proteins, identified by immunoblotting assay as various subunits of mitochondrial respiratory chain complexes and calmodulin, were particularly impaired. Chronic treatment with CDP-choline at a dose of 20 mg/kg body weight per day for 28 days caused significant changes in the amounts of several of the above mentioned proteins. Most of the proteins, which decreased during aging, showed a significant increase after CDP-choline treatment compared with the corresponding control values at the same age. The effect of CDP-choline might be due to: the increased availability of cytidylic nucleotides, which in the brain are present in limited amounts compared to the other nucleotides; the increased content of total adenine nucleotides; the improvement of brain energy metabolism.

Modifications of synaptosomal plasma membrane protein composition in various brain regions during aging

The age-dependent modifications of synaptosomal plasma membrane protein composition in three different rat brain regions (cerebral cortex, cerebellum and striatum) at various ages (4, 12 and 24 months) were studied. The proteins were separated by gel-electrophoresis and the quantity of the different polypeptides was determined densitometrically from the stained gels. In the three brain regions examined several age-related modifications in the amount of the synaptosomal plasma membrane proteins were observed. In particular a significant decrease in the content of some synaptosomal plasma membrane proteins at 24 months of age was found. The age-related modifications in the protein composition of synaptosomal plasma membrane may cause changes in many brain functions, such as neurotransmission, ionic transport and enzyme activities. Particularly interesting is the decrease of a protein with 18 kDa mol. wt. This protein has been identified as calmodulin by immunoblotting assay. The decrease in the amount of this protein may be correlated to the impairment of several Ca(2+)-requiring processes in the aging brain.

Effect of hypoxia on protein composition of synaptic plasma membranes from cerebral cortex during aging

The effect of hypoxia on the protein composition of synaptic plasma membranes (SPM) isolated from cerebral cortex of rats at 4, 12, and 24 months of age was investigated. The proteins were separated by SDS polyacrylamide gel electrophoresis and the percent content was evaluated by measuring the optical density of the stained gels. After hypoxic treatment various proteins showed significant changes. Some proteins were only affected at 4 and 12 months of age and not at 24 months. The various modified proteins may be identified according to their molecular weight, as follows: the 18 kDa protein with calmodulin; the 23 kDa protein with D3 subunits; the 28 kDa protein could contain the delta subunit of the Ca2+ channel. The changes in the amount of some SPM proteins during hypoxia is consistent with the alteration in membrane polarization and neurotransmission observed in this condition. The effect of aging at the synaptosomal level seems to be a selective process; after hypoxia the age-related changes of many proteins are more pronounced.

Effect of hypoxia on mitochondrial protein composition of cerebral cortex during aging

The effect of hypoxia on the protein composition of mitochondria from cerebral cortex of rats at 4, 12, and 24 months of age was investigated. The proteins were separated by electrophoresis on SDS polyacrylamide gels and the percent content was evaluated by measuring the optical density of the stained gels. The results demonstrate that hypoxic treatment causes a decrease in the amount of some proteins as follows: the 90 and the 16 kDa Mw proteins at 4 months; the 82 and the 79 kDa Mw proteins at 24 months; the 52-49, 35 and 20 kDa at all ages investigated; the 44 kDa protein at 4 and 12 months and the 28 kDa protein at 4 and 24 months of age. Our results show that hypoxic conditions affect mitochondrial protein composition to a greater extent than aging alone.

ADP-ribosylation of proteins in brain regions of rats during postnatal development

Post-translational modifications of chromatin-bound proteins play an important role in the regulation of eukaryotic gene expression. Processes such as acetylation, methylation, phosphorylation and ADP-ribosylation may alter the interaction of these proteins with DNA and consequently affect chromatin conformation and the binding of enzymes and other molecules involved in the regulation of gene expression. In the present study the process of ADP-ribosylation of chromosomal proteins (histone and non-histone proteins) in some rat brain regions during postnatal development was investigated; also the effect of epidermal growth factor (EGF) on this process in fetal brain slices was studied. It has been found that the process of ADP-ribosylation of total histones extracted from rat cerebral cortex and cerebellum at 1, 10 and 30 days of age, increases from 1 to 10 days of age (i.e. the period of maximal cell proliferation) and decreases thereafter, while the process of ADP-ribosylation of non-histone proteins (NHPs) sharply decreases during the same developmental period. The addition of EGF to fetal brain slices causes a significant increase of ADP-ribosylation of total histones (particularly of the histone H1 fraction) and also of NHPs and microsomal proteins. This result is in agreement with the effect of EGF as a mitogen factor, previously shown in astroglial cell cultures.

Age-dependent changes of nucleic acid labeling in different rat brain regions

The effects of aging on in vivo DNA and RNA labeling and on RNA content in various brain regions of 4-, 12-, and 24-month-old rats were investigated. No difference in [methyl-14C]thymidine incorporation into DNA of cerebral cortex and cerebellum during aging was observed. The ratio of RNA/DNA content significantly decreased from 4 to 24 months of age in cerebral cortex, cerebellum and striatum. RNA labeling decreased by 15% in cerebral cortex of 24-month-old animals while in the other brain areas examined (cerebellum, hippocampus, hypothalamus, brainstem, striatum) did not change during aging. In the cerebral cortex, the ratio of the specific radioactivity of microsomal RNA to that of nuclear RNA, determined by in vivo experiments, was not affected by the aging process. A significant decrease of total, poly(A) RNA and poly(A) RNA content was observed in the same brain area of 24-month-old rats compared to 4-month-old ones. Moreover, densitometric and radioactivity patterns obtained by gel electrophoresis of labeled RNA after in vitro experiments (tissue slices of cerebral cortex) showed a different ribosomal RNA processing during aging. In vivo chronic treatment with CDP-choline was able to increase RNA labeling in corpus striatum of 24-month-old animals.

Age-dependent modifications of mitochondrial proteins in cerebral cortex and striatum of rat brain

The protein composition of free mitochondria purified from cerebral cortex and striatum during aging was analyzed by gel electrophoresis. Mitochondria were isolated from cerebral cortex and striatum of 4-, 12-, and 24-month-old rat brain. The percent amount of mitochondrial proteins after gel-electrophoretic separation was determined densitometrically. A significant decrease in the amount of two polypeptides (with molecular weights of 20 and 16 kDa, respectively) in both brain regions during aging was found. The decrease was higher in the striatum indicating a greater vulnerability of this brain area to the aging process. The age-dependent modifications of mitochondrial proteins observed may play an important role in several mitochondrial functions, such as energy transduction and transport processes as well as in structural changes occurring with age, causing altered membrane permeability and fluidity.

Effect of epidermal growth factor on the labeling of the various RNA species and of nuclear proteins in primary rat astroglial cell cultures

This study investigated the effects of epidermal growth factor (EGF) on the labeling of various RNA species and of nuclear proteins in primary rat astroglial cell cultures. After 12 hours of EGF treatment in serum-free medium or chemically defined medium, significant increase in RNA labeling, and also in acid-soluble radioactivity and RNA content, was observed. The ratio RNA/DNA was significantly higher in EGF-treated cultures compared with controls. Ribosomal RNAs (28S and 18S), polyadenylated, and nonpolyadenylated RNAs showed a higher specific radioactivity in EGF-treated cultures. Among the nuclear proteins, the labeling of basic proteins was enhanced by EGF treatment, whereas that of total nuclear acidic protein (NHPs) was less modified, except for some NHPs separated by gel electrophoresis with a molecular weight (MW) approximately 95-83 and 44 kd, which were significantly more labeled in EGF-treated cultures.

Protein synthesis rates in rat brain regions and subcellular fractions during aging

In vivo protein synthesis rates in various brain regions (cerebral cortex, cerebellum, hippocampus, hypothalamus, and striatum) of 4-, 12-, and 24-month-old rats were examined after injection of a flooding dose of labeled valine. The incorporation of labeled valine into proteins of mitochondrial, microsomal, and cytosolic fractions from cerebral cortex and cerebellum was also measured. At all ages examined, the incorporation rate was 0.5% per hour in cerebral cortex, cerebellum, hippocampus, and hypothalamus and 0.4% per hour in striatum. Of the subcellular fractions examined, the microsomal proteins were synthesized at the highest rate, followed by cytosolic and mitochondrial proteins. The results obtained indicate that the average synthesis rate of proteins in the various brain regions and subcellular fractions examined is fairly constant and is not significantly altered in the 4 to 24-month period of life of rats.

DNA-4'-6-diamidine-2-phenylindole interactions: a comparative study employing fluorescence and ultraviolet spectroscopy

DAPI is a drug that interacts with double-stranded nucleic acids, binding preferentially to A + T base pairs. The interaction is not intercalative, therefore providing a useful model for mimicking the effect of functional molecules in modifying specific sites, namely, A + T segments, of significance in gene expression. Knowledge of the nature of such interaction has been enriched by additional information obtained from comparative analysis of the data acquired by uv spectroscopy and fluorescence. Two classes of binding sites, defined by different apparent affinity constants and numbers of binding sites, are evident. All types of interaction are dependent on the nucleic acid/dye ratio and on the ionic strength of the medium.

Effect of undernutrition on some enzymes involved in the salvage pathway of purine nucleotides in different regions of developing rat brain

The effect of undernutrition on the activity of two key enzymes of purine salvage pathway, namely hypoxanthine-guanine phosphoribosyltransferase (HGPRTase) and adenine phosphoribosyltransferase (APRTase), in cerebral hemispheres, cerebellum and brain stem of rats at different days of postnatal development was studied. The activity of HGPRTase and of APRTase is significantly lower in all brain regions of undernourished animals at 5 days after birth; between 10 and 15 days of age there is a recovery of the enzymatic activity which is particularly evident in the cerebellum. Successively both enzymatic activities decrease reaching at 30 days of age values quite similar to those of controls. These results indicate that undernutrition during fetal and postnatal development, impairs and delays the activity of the enzymes of purine salvage pathway.

Effect of undernutrition on some enzymes of purine metabolism in different regions of developing rat brain

The effect of undernutrition on the activity of some enzymes involved in purine metabolism, ie, adenosine aminohydrolase, adenylate aminohydrolase, and inosine phosphorylase in cerebral hemispheres, cerebellum, and brain stem of rats at different days of postnatal development was studied. Adenosine aminohydrolase, adenylate aminohydrolase, and inosine phosphorylase were assayed by radiochemical methods which involve the measurement of the radioactive products formed, ie, inosine, IMP, and hypoxanthine, respectively. The results obtained indicate that undernutrition affects the activity of the enzymes which control the concentration of purine nucleotides to a different degree in the three brain regions examined.

Pool and synthesis of phosphoribosylpyrophosphate in rat embryo cells infected with X14 or H-1 parvovirus

In rat embryo cell cultures infected with X14 or H-1 parvovirus the PRPP pool and the PRPP synthetase activity have been assayed. A radiometric method, prepared by Authors, based on the conversion of [6-14C) orotate to [6-14C) UMP by the mixed enzyme orotate phosphoribosyltransferase and orotidylate decarboxylase and on the separation of UMP by ascending chromatography, has been utilized. The PRPP pool and te PRPP synthetase activity appeared nearly unmodified in the cells infected with X14 or H-1 parvovirus compared to the mock-infected cells. Therefore, the lowered pyrimidine nucleotide synthesis in infected cells, shown in previous studies, may depend, rather than on the diminished PRPP pool, on the lower PRPP utilization; in fact, some inhibition by metabolites, that may be removed by added PRPP, might occur in the infected cells.

Changes of nucleic acid and protein synthesis in hypertrophied guinea-pig heart during intermittent hypoxia

The effect of intermittent normobaric hypoxia on nucleic acid and protein synthesis of guinea-pig heart was studied. De novo synthesis of purine nucleotides, of RNA and DNA, as well as RNA polymerase activities and protein synthesis, increased in the heart right ventricles of hypoxic animals compared to the controls. These results suggest an activation of cellular genetic apparatus with an increase of nucleic acid and protein syntheses during the compensatory processes following hypoxia.

Pyrimidine nucleotide synthesis in rat embryo cells infected with X14 or H-1 parvovirus

The activity of some enzymes involved in pyrimidine nucleotide synthesis was studied in rat embryo cell (REC) cultures infected with X14 or H-1 parvovirus. dCMP aminohydrolase activity of the infected cells was 64--121% greater than that of the mock-infected cells. dTMP synthetase activity was 18% greater in X14 virus-infected cells and 34% lower in H-1 virus-infected cells. These results suggest some differences in the infected cells, as regards the biosynthesis of dTMP. Orotate phosphoribosyltransferase and orotidylate decarboxylase activities appeared nearly unmodified compared to the mock-infected cells. The addition of phosphoribosylpyrophosphate (PRPP) to the cell suspension incubated with [6-14C] orotate increased the specific radioactivity of acid-soluble uracil, 5-fold in the mock-infected cells and 15- --24-fold in the X14 or H-1 virus-infected cells (72 hr p.i.). This result suggests that the lowered pyrimidine nucleotide synthesis in infected cells depends to a large extent on the diminished PRPP pool.

Nucleic acid biosynthesis in rat embryo cells infected with X14 or H-1 parvovirus

Nucleic acid biosynthesis was studied in rat embryo cell (REC) cultures 48 hours after infection with X14 or H-1 parvovirus. The incorporation of 14C-formate and [6-(14C]-orotic acid into purines and pyrimidines of various was lowered after infection with these parvoviruses. 14C-Formate incorporation into acid-soluble thymine was greatly inhibited in H-1 virus-infected cells whereas it was slightly inhibited in X14 virus-infected cells. These results suggest that X14 virus-infected cells can carry out the biosynthesis of thymidylic acid utilizing some endogenous pyrimidine nucleotide (e.g. deoxycytidylic acid, via deoxyuridylic acid). In the infected cells, the nucleoplasmic RNA polymerase activity was strongly inhibited. This results suggests an interference by the two viruses with hosts RNA synthesis.