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Biomedical subjects

M A Castellano

Publications and source records attributed to M A Castellano.

At least 19 recordsLinked to original sources
PubMed2001

Opposite effects of low and high doses of arginine on glutamate-induced nitric oxide formation in rat substantia nigra.

L-arginine is a very versatile amino acid that is involved in many important physiological processes such as protein, nitric oxide (NO), agmatine, putrescine, urea, L-ornithine or creatine synthesis and is essential for posttranslational arginylation of protein. The present study was designed to evaluate in vivo the effect of L-arginine on NO production in substantia nigra. In vivo spectroscopic and voltammetric studies were addressed in rats to record modifications in methemoglobin and NO levels under glutamate stimulation. Results showed that, under physiological L-arginine extracellular concentration, the intranigral infusion of glutamate produced an increase in NO levels. When a low dose of L-arginine was co-infused with glutamate, a persistent and higher increase in NO levels was observed. The co-infusion of glutamate with a moderate dose of L-arginine induced drastic and persistent NO production. It was also observed that high doses of either L-arginine or D-arginine inhibit NO production. Subsequently, these data show that L-arginine and D-arginine are involved in a mechanism that inhibits NO production.

Animals↗
PubMed2000

Grapevine fleck virus-like viruses in Vitis.

Two sets of degenerate primers for the specific amplification of 572-575 nt and 386 nt segments of the methyltransferase and RNA- dependent RNA polymerase cistrons of members of the genera Tymovirus and Marafivirus and of the unassigned virus Grapevine fleck virus (GFkV) were designed on the basis of available sequences. These primers were used for amplifying and subsequent cloning and sequencing part of the open reading frame 1 of the genome of GFkV, Grapevine asteroid mosaic-associated virus (GAMaV) and of another previously unreported virus, for which the name Grapevine red globe virus (GRGV) is proposed. Computer-assisted analysis of the amplified genome portions showed that the three grapevine viruses are phylogenetically related with one another and with sequenced tymoviruses and marafiviruses. The relationships with tymoviruses was confirmed by the type of ultrastructural modifications induced in the host cells. RdRp-specific degenerate primers were successfully used for the aspecific detection of the three viruses in crude grapevine sap extracts. Specific virus identification was obtained with RT-PCR using antisense virus-specific primers.

Amino Acid Sequence↗
PubMed2000

Immunodetection and subcellular localization of the proteins encoded by ORF 3 of grapevine viruses A and B.

Polyclonal antisera were raised to Escherichia coli-expressed ORF3 products (putative movement proteins) of Grapevine virus A (GVA) and Grapevine virus B (GVB) (genus Vitivirus), and used for their immunodetection in infected plants. Western blot analysis of subfractionated cellular compartments showed that the distribution of both proteins was comparable to that of plant virus movement proteins, as they were transiently present in a crude membrane fraction and accumulated in a cell wall-enriched fraction. The GVA ORF3-encoded protein, but not the comparable GVB protein, was also present in large amount in a cytoplasmic soluble fraction. Intracellular immunogold labelling localized these proteins in the cell wall and plasmodesmata of infected cells and, especially for GVA, in association with cytoplasmic virus aggregates.

Blotting, Western↗
PubMed1999

Synthesis of infectious transcripts of olive latent virus 1: genes required for RNA replication and virus movement.

Genomic RNA of olive latent virus 1 (OLV-1) contains five open reading frames (ORFs) encoding proteins of 23, 82, 8, 6 and 30 (CP) kDa. A full-length cDNA copy of OLV-1RNA was prepared and cloned in a low-copy-number vector (pMUC-19) downstream of or T7 RNA polymerase promoter. Transcripts derived from this template, denoted pMUC-OLV, were highly infectious when inoculated in local and systemic hosts and infected tissues contained virus-like particles. Genes required for replication and virus movement were mapped by site-directed and deletion mutogenesis of the pMUC-OLV. ORF1 and ORF2 mutants were not viable, suggesting that replication requires the 23 and 82 kDa proteins. The 8 and 6 kDa polypeptides were involved in cell-to-cell movement, since their absence did not interfere with RNA replication but prevented systemic infection of inoculated plants. Mutant clones in R and S domains of the CP gene could replicate, but they did not systemically infect Nicotiana benthamiana, indicating that the CP gene is required for OLV-1 long-distance translocation. Mutant clones with large deletions in the CP gene were not viable, probably due to loss of 3'-proximal sequences required for RNA replication.

Gene Expression Regulation, Viral↗
PubMed1999

Subcellular localization and in vivo identification of the putative movement protein of olive latent virus 2.

The gene encoding the 36.5 kDa ('36K') nonstructural protein located on RNA3 of olive latent virus 2 (OLV-2) was cloned, expressed with the Escherichia coli pGEX-2T system and the purified protein used to raise a polyclonal antiserum. Immunoblot analysis of OLV-2-infected Nicotiana benthamiana plants showed that the 36K protein accumulated in the early stages of infection and was associated with a subcellular fraction enriched in cytoplasmic membranes. In infected cells there were tubular structures, some containing virus-like particles, scattered in the cytoplasm or protruding from or penetrating the cell wall at the plasmodesmata. Immunogold labelling localized the 36K protein in the plasmodesmata of OLV-2-infected cells and showed it to be associated with virus-containing tubules. Leaf trichome cells of N. tabacum plants, transformed with a 36K-green fluorescent protein (GFP) fusion construct, revealed localized fluorescence in the cell walls, possibly due to association of the fusion protein with plasmodesmata. When the same 36K-GFP fusion protein was expressed in N. tabacum protoplasts, long tubular fluorescent structures protruded from the protoplast surface, suggesting that the 36K protein is responsible for tubule induction. The conclusion is drawn that this protein is likely to be the OLV-2 movement protein, mediating cell-to-cell virus movement, and that movement is by a tubule-guided mechanism.

Bromoviridae↗
PubMed1999

Action of antidepressant drugs on maternal stress-induced hypoactivity in female rats.

It has been reported that rats forced to swim in a restricted space assume, after initial frenzied attempts to escape, an immobile posture. Porsolt et al. referred to this phenomenon as "behavioral despair", an animal model of depression. Prenatal stress induces an increase of behavioral depression in adult female offspring. This study presents new evidence supporting the hypothesis that maternal stress during gestation increases the risk of depression in the offspring since immobility time was modified by antidepressant drugs (tricyclics and an atypical antidepressant). In rats, amitriptyline (5 mg/kg), imipramine (5 mg/kg) and nomifensine (1 mg/kg) decreased the immobility time in Porsolt test in offspring of mothers stressed during gestation. Moreover, increasing doses of amitriptyline (1, 5, 25 and 40 mg/kg) reduced depression in the forced swimming test in dose-dependent manner.

Amitriptyline↗
PubMed1993

Spontaneous firing of nigrostriatal dopaminergic neurons in split-brain rats.

The regulatory action of the contralateral brain side on nigrostriatal dopaminergic (NSDA) neurons was examined in anesthetized rats using extracellular single-unit recording techniques. The spontaneous activity of NSDA cells was recorded from split-brain, sham-lesioned or intact-brain rats. The three groups of cells did not differ in antidromic latency and firing rate. However, cells from split-brain rats exhibited a more regular pattern of discharge than those recorded in the two control groups as shown by autocorrelograms and the standard deviation and variation coefficient of the interspike intervals. In addition, burst firing was found to be markedly reduced in the split-brain group. It is concluded that decussating pathways are involved in the regulation of the discharge pattern of NSDA neurons.

Action Potentials↗
PubMed1993

Properties of a filamentous virus isolated from grapevines affected by corky bark.

A virus with highly flexuous filamentous particles c. 800 nm long, showing distinct transverse striations was isolated with high frequency (60%) by inoculation of Nicotiana occidentalis with sap from grapevine accessions indexing positive for corky bark. The virus, for which the name grapevine virus B (GVB) is proposed, has an ssRNA genome with mol. wt. of c. 2.5 x 10(6) Da (c. 7600 nt) and coat protein subunits with mol. wt. of c 23,000 Da. GVB has a very restricted herbaceous host range and was experimentally transmitted by the mealybug Pseudococcus ficus. The physicochemical and ultrastructural properties of GVB resemble those of closteroviruses. However, it is serologically unrelated to other grapevine closteroviruses including grapevine virus A, with which it shares some biological and physicochemical properties.

Capsid↗
PubMed1993

Transfected D2 short dopamine receptors inhibit voltage-dependent potassium current in neuroblastoma x glioma hybrid (NG108-15) cells.

Two isoforms of the D2 dopamine receptor exist, termed D2 short (D2s) and D2 long, which differ by the presence or absence of 29 amino acids. To examine the possible coupling of the D2s isoform to voltage-dependent K+ current, NG108-15 cells that were transfected with and stably express this isoform were studied using whole-cell patch-clamp techniques. In transfected, but not untransfected, cells dopamine and quinpirole (QUIN) reduced the normally observed peak outward K+ current, and this effect was abolished by the D2 antagonist sulpiride but not by the alpha 2-adrenergic receptor antagonist idazoxan or the D1 antagonist (R)-(+)-SCH-23380. The D1 receptor agonist SKF 38393 had no effect. QUIN-induced inhibition of K+ current was prevented by loading the cells with the Ca(2+)-chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, suggesting a critical role for intracellular Ca2+ mobilization. In contrast, reduction of the concentration of extracellular Ca2+ and inclusion of the Ca2+ channel blocker cobalt did not modify the reduction of K+ current produced by stimulation of D2s receptors. A critical role for intracellular calcium mobilization in the observed effects was further supported by the observation that increases in cytosolic Ca2+ produced by thapsigargin mimicked the effect of QUIN, whereas intracellular ryanodine, which blocks Ca2+ mobilization, abolished the QUIN responsiveness. Finally, the effect of D2S activation on K+ current was not modified by pretreatment of the cells with pertussis toxin. These results suggest that the D2s dopamine receptor expressed in NG108-15 cells inhibits the activity of native K+ current via a mechanism that is dependent upon the mobilization of intracellular Ca2+ and does not involve a pertussis toxin-sensitive G protein.

Calcium↗
PubMed1992

Production, characterization and use of monoclonal antibodies to grapevine virus A.

Four stable hybridoma cell lines secreting monoclonal antibodies to grapevine closterovirus A (GVA) were obtained by fusing spleen cells of immunized BALB/c mice with mouse myeloma cell line Sp2/0-Ag 14. In ELISA all MAbs reacted with virus in leaf extracts from Nicotiana benthamiana, glass-house-, field-, or in vitro-grown grapevines, or with cortical shavings from mature grape canes. In IEM tests, only one of the MAbs (PA3.F5) decorated virus particles on the entire surface. This MAb was likely induced by a surface antigenic determinant, whereas the other three MAbs (PA3.D 11, PA3.C 6, and PA3.B 9) were originated by cryptotopes. Coupling polyclonal antibodies for coating protein A-sensitized plates, and monoclonal antibody conjugates for antigen detection, gave highly efficient and reproducible results for identification of GVA in field-grown grapevines.

Antibodies, Monoclonal↗
PubMed1992

Properties of a previously undescribed grapevine nepovirus from Tunisia.

A virus with isometric particles c. 30 nm in diameter and angular contour was isolated by inoculation of sap from a Tunisian grapevine with mild mottling and leaf deformation. The virus sedimented in sucrose density gradients as three components: T (empty shells), M (particles containing a molecule of ssRNA with an apparent size of 5,800 nucleotides, constituting 35% of the particle weight) and B (particles containing a molecule of ssRNA with apparent size of 6,800 nucleotides, constituting 41% of the particle weight). Virus particles had buoyant densities of 1.31 (T), 1.45 (M), and 1.49 g/cm3 (B) in cesium chloride equilibrium gradients. The coat protein subunits consisted of a single polypeptide with mol. wt. of c. 59,000 daltons. An antiserum was produced with a titer of 1:256, which did not react with healthy plant antigens. Cells of artificially infected herbaceous hosts showed cytoplasmic vesiculate-vacuolate inclusion bodies, virus-containing tubules, mostly associated with plasmodesmata and/or cell wall protrusions, and crystalline aggregates of virus particles and empty capsids. The physicochemical and ultrastructural properties of this virus resemble very much those of nepoviruses. However, it was serologically unrelated to 19 different members of the group, including all those reported to infect grapevines. Therefore, the virus is possibly a hitherto unreported nepovirus for which the name of grapevine Tunisian ringspot virus (GTRV) is proposed.

Capsid↗
PubMed1991

Behavioral lateralization in rats: prenatal stress effects on sex differences.

The possible relationship between human and animal asymmetries is currently a controversial point. In the present study we report that, after practice, rat behavioral asymmetry presents important similarities with human laterality. Thus, rat behavior presents: (1) absolute and population laterality to the same degree and with the same right-bias as that reported for humans; (2) the female has less absolute laterality but similar population laterality to the male; (3) male-female differences for behavioral laterality are modified by prenatal stress as occurs with similar other hormone-regulated behavior.

Analysis of Variance↗
PubMed1991

Sex differences in behavioral despair: relationships between behavioral despair and open field activity.

Many studies have reported sex differences in the rates of depression in humans. Due to experimental problems, the nature of these sexual differences is still unknown. In the present study, we quantify the sex differences in depression using two animal models. Both the Porsolt et al. test and the Hilakivi and Hilakivi forced swimming test have shown that the duration of immobility is higher in the male than in the female. Sexual differences in the animal models of depression are probably unrelated to general activity differences because there is no significant correlation between activity in both tests. However, the correlation between the two models of depression used reached statistical significance. Finally, the immobility levels in the Porsolt test were similar in the different stages of the estrous cycle.

Animals↗
PubMed1991

Nigrostriatal dopaminergic cell activity is under control by substantia nigra of the contralateral brain side: electrophysiological evidence.

The biochemical balance between right- and left-ascending DA systems is an essential factor to regulate behavioral lateralization. However, there is no electrophysiological evidence for the regulation of interhemispheric DA systems. In the present paper we report electrophysiological evidence supporting the hypothesis that the A9 DA cells are under control of the contralateral substantia nigra. The activity of more than 80% of the A9 cells recorded was affected by contralateral SN stimulation. This is a very high proportion because the previously reported response of A9 cells to ipsilateral caudate stimulation is proportionally lower. The potency of a stimulus, estimated as the number of action potentials induced or inhibited by each electrical stimulation of the contralateral substantia nigra or by the percentage of modification in the number of action potentials induced or inhibited in relation to the spontaneous potential expected, was also high. The response to the contralateral stimulation was complex. Fifty-four percent of all the DA cells studied showed more than a single response. Forty-four percent showed at least one stimulation and at least one inhibition. Because 1) the percentage of cells with at least one stimulation (70%) was higher than the percentage of cells with at least one inhibition (56%), and 2) the potency of stimulations was higher than the inhibition potency, the present data provide evidence that contralateral control of A9 cells is mainly excitatory. The percentage of cells activated by contralateral stimulation was high, between 30 ms and 220 ms and between 400 ms and 700 ms. The probability of inhibition was higher than the probability of activation between 10 ms and 30 ms and between 230 and 380 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Interhemispheric regulation of dopaminergic ascending systems.

There are previous evidences of biochemical and functional interhemispheric asymmetry for central dopaminergic systems. The purpose of the current study was to establish an evidence of the existence of mechanisms for interhemispheric regulation of dopaminergic systems. The initial hypothesis was that to compensate the spontaneous interhemispheric asymmetry, the brain side with lower dopamine (DA) concentration show a higher DA turnover. The ratio of metabolite/neurotransmitter was computed as an index of presynaptic turnover rate. Both striatum and hippocampus showed a DOPAC/DA index higher in the brain side with a lower DA concentration. In addition, we found an inverse relation between the interhemispheric index of DA and interhemispheric index of DA turnover. Taken together the present data provide evidence of an interhemispheric regulation for the DA-innervation of both striatum and hippocampus in normal unlesioned rats.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Behavioral lateralization in rats and dopaminergic system: individual and population laterality.

Recently, we reported that practice facilitates the expression of the behavioral asymmetry in rats at individual and population levels. In the present study we investigated the side preference in the performance of four different tasks during 10 successive days. The practice increased individual laterality and internal consistency in all tasks. In addition, practice facilitated the expression of marked population laterality in two tasks (78.1% and 63.3% for right bias). The influence of dopaminergic systems on these behaviors was evaluated with apomorphine and with 6-hydroxydopamine lesions ipsi- and contralateral to the side preference. The results suggest that there is a presynaptic dominance contralateral to the side preference in the four tests. However, as influences of dopaminergic systems were different in each task and because the tests were unrelated, the results suggest that the behavioral laterality in rats, as in humans, is a phenomenon caused by different and relatively independent systems.

Animals↗
PubMed1988

Results of noncomparative studies of cefotetan in the treatment of obstetric and gynecologic infections.

In a multicenter trial involving 11 centers, 160 women were enrolled to evaluate the safety and effectiveness of 1 or 2 gm of cefotetan administered every 12 hours in the treatment of obstetric and gynecologic infections. The 133 evaluable patients generally were under 25 years of age, were nonwhite, and had hospital-acquired endometritis or pelvic inflammatory disease caused by both aerobic and anaerobic bacteria. Escherichia coli, Neisseria gonorrhoeae, group D streptococci, Bacteroides sp., and Peptococcus sp. were among the most frequently isolated pathogens. The patients were treated for a mean of 5.6 +/- 1.6 days and received a total dose of 19.27 gm. The signs and symptoms of infection were cleared or improved in 93% of the 133 patients evaluable for clinical response. Of the 116 evaluated bacteriologically, 95% had a satisfactory or presumed satisfactory response; only six patients (5%) were considered to be bacteriologic failures. Differences in the results of several clinical laboratory tests performed before and after treatment were statistically, but not clinically, significant (p less than 0.05). Safety was evaluated in the 158 patients who received cefotetan, and only four (3%) had adverse reactions considered related to the drug. Cefotetan was clearly effective and produced no untoward reactions in these women with obstetric and gynecologic infections caused by both aerobic and anaerobic organisms when administered at 1 or 2 gm every 12 hours.

Adult↗