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Biomedical subjects

M Mariotti

Publications and source records attributed to M Mariotti.

At least 91 records · Page 5Linked to original sources
PubMed1989

[DNA amplification using the polymerase chain reaction method applied to the detection of HIV-1 in seropositive subjects and in seronegative subjects at risk].

Polymerase Chain Reaction (PCR) allows the amplification of specific segments of Human Immunodeficiency Virus (HIV) genome. This technique is of interest for direct detection of HIV-1 DNA sequences in peripheral blood mononuclear cells. In our study, 54 out of 55 HIV-1 seropositive subjects were found positive with PCR assay. No detection of HIV DNA was observed in 36 seronegative at risk subjects (16 homosexuals and 20 polytransfused haemophiliacs), in 20 subjects with isolated and persistent anti-core antibodies, in 20 thalassemic polytransfused children and in 74 HIV seronegative blood donors (negative controls). These results are consistent with those of classical HIV serology and indicate that latent HIV-1 infection in seronegative at risk subjects is not a frequent event, if it exists.

Adult↗
PubMed1987

Medialis dorsalis thalamic unitary response to tooth pulp stimulation and its conditioning by brainstem and limbic activation.

In nembutalized cats tooth pulp stimulation (TPS) was effective in exciting 18% of medialis dorsalis (MD) thalamic units. Facilitation of spontaneous MD unitary discharge followed high frequency stimulation of the lateral amygdala (25%), dorsal hippocampus (22%), mesencephalic reticular formation (20%) and septal nuclei (17%). Conditioning high-frequency stimulation of limbic and reticular structures, strongly facilitated the MD unitary responses to TPS. None of the thalamic neurons involved in nociception seems to project to the cerebral cortex. The conditioning effect on MD response of limbic and reticular stimulation suggests that these central structures may be involved in the modulation of the nociceptive input.

Animals↗
PubMed1987

Limbic and brainstem afferents to thalamic mediodorsal nucleus: a horseradish peroxidase study.

Subcortical ipsilateral afferents to mediodorsal (MD) thalamic nucleus were investigated by retrograde transport of horseradish peroxidase (HRP). HRP was injected into the rostral and caudal part of MD following both a vertical and an oblique stereotaxic approach. We have identified MD afferents from the following structures: area septalis, amygdaloid complex, hypothalamus, mamillary bodies, tuberculum olfactorium, claustrum, ventral tegmental area, zona incerta, substantia nigra, griseum centralis, formatio reticularis mesencephali and pontis oralis. The projections from hypothalamus, amygdaloid nuclei and area septalis and reticular formation are in agreement with the integrative function of sensory afferents of this thalamic nucleus.

Animals↗
PubMed1987

DNA polymorphisms associated with HLA-B-like genes and evidence for a duplication of B40 genes detected with an HLA-B-specific DNA probe.

Analysis of polymorphic DNA endonuclease restriction fragments by Southern blotting indicates that the genetic complexity of the HLA class I gene family is larger than the complexity indicated by serologically defined HLA-A, -B and -C gene products (Orr et al., 1982). There are correlations between polymorphic restriction endonuclease fragments in a limited number of HLA class I alleles; in fact, a few alleles in the population have been correlated with the presence of polymorphic DNA fragments (Cann et al., 1983; Cohen et al., 1983; Orr & De Mars, 1983; Lucotte, Coulondre & Salmon, 1985; Driesel et al., 1985). Recently, probes shown to be specific for HLA-A and HLA-B genes (Grumet et al., 1983; Koller et al., 1985) were constructed from the 3'-untranslated region of these genes.

HLA Antigens↗
PubMed1987

Taq I restriction polymorphism of HLA class-I genes, and hybridization with HLA-A and HLA-B specific probes.

Restriction enzyme site polymorphisms for Taq I endonuclease are examined in a panel of DNAs of HLA-typed individuals and families. Using a full-length DNA probe, 13 polymorphic bands were detected in a total of 31 restriction fragments analyzed. Only one of them (the 3.5-kb polymorphic band) correlated absolutely with serological allele B27, as already established. The A- and B-specific probes recognized only a very small subset (4 for the A probe, and 2 for the B probe) of the DNA fragments which were hybridized with the full-length DNA probe. For each of these two loci, a frequent polymorphism was described, which correlated with serologic haplotypes in several families studied.

Alleles↗
PubMed1987

Taq I polymorphism of HLA class I genes in an ankylosing spondylitis family.

A 3.5-kb HLA class I fragment is polymorphic in an ankylosing spondylitis (AS) family. All B27 AS patients show the 3.5-kb band, which is also present in B12 AS patients in this family. When hybridized with an HLA-B-specific probe, the polymorphic band is revealed in B12 patients, but not in B27 patients.

Alleles↗
PubMed1986

[Characteristic parameters of the population of circulating DNA in cases of disseminated lupus erythematosus ].

Important quantities of circulating DNA (up to congruent to 50 micrograms/ml) have been shown to be present in the sera of patients with serious systemic lupus erythematosus. This DNA is double-stranded, as demonstrated by colorimetric, enzymatic and biophysic tests. The circulating DNA population is made up of a main fraction at 250 base pairs and a heterogeneous tail up to 300 bases pairs, as demonstrated by electrophoretic measures on polyacrylamide gel. After hydrolysis in limited conditions with DNAse I and 32P labelling, the repartition of autoradiographed material confirms the reality of a main peak and of a more dispersed tail.

Autoradiography↗
PubMed1983

Cytotoxicity of anti-PP1Pk antibodies and possible relationship with early abortions of p mothers.

IgG and IgM anti-PP1Pk antibodies of human sera from p individuals were examined for their ability to agglutinate red blood cells (RBC) of various P phenotypes and to mediate ADCC of these RBC by human effector cells. Agglutinating antibodies were found in either the IgG or the IgM fraction, while ADCC active antibodies were found mainly in the IgG fraction and were essentially cytotoxic with Pk RBC. The possible relationship of these antibodies with early abortions of p mothers is discussed.

Abortion, Spontaneous↗
PubMed1983

Mesencephalic and bulbar reticular influences on somatosensory cortical neurons: short- and long-latency effects.

Somatosensory cortical neurons were intracellularly and extracellularly recorded in cats encéphale isolé, and after acute lesions of midthalamic nuclei or after chronic hemisection of the brain stem at the pretrigeminal level. Intracellular recordings showed postsynaptic facilitatory and inhibitory effects at very low latency by stimulating both the mesencephalic (MRF) and bulbar reticular formation (BRF). Inhibitory effects dominated by stimulating the BRF. Neither midthalamic lesions nor pretrigeminal hemisection changed the quality of latency of postsynaptic responses. Extracellular recordings revealed long-latency inhibition of discharge following MRF stimulation after midthalamic lesion. In these experimental conditions long-latency BRF effects were abolished. No differences were found in responses of pyramidal tract (PT) or non-PT neurons during BRF and MRF stimulation. The results are discussed on the basis of a possible extrathalamic differential reticular control, from caudal and rostral brain stem, of somatosensory cortical neurons.

Animals↗
PubMed1983

Differential effects of benzodiazepines on EEG activity and hypnogenic mechanisms of the brain stem in cats.

The effects of quazepam, flurazepam and diazepam (0.12-1 mg/kg i.v.) on cortical electroencephalogram (EEG) and EEG power spectra were studied in cats with lesioning at various levels of the brain stem (encéphale isolé, midpontine pretrigeminal and cerveau isolé preparations). In the encéphale isoleé, quazepam produced slow waves, spindles and power increases in the 0.5-14 Hz range. Flurazepam produced similar EEG activity but alternated with fast frequency rhythms (8-14 Hz) of moderate amplitude. Diazepam produced spindles superimposed on a continuous fast frequency background while the slow waves were not observed. In the midpointine cats, quazepam modified the desynchronized EEG only at the higher doses. It enhanced the fast rhythms (10-14 Hz) observed in controls. Flurazepam produced similar effects but to a great extent. EEG effects of diazepam were similar to those observed in the encéphale isolé. Thus, the midpontine transection precluded the appearance of the slow wave synchronization. None of the benzodiazepines affected the synchronized EEG of the cerveau isolé. It is suggested that quazepam and, at least in part, flurazepam may induce EEG synchronization and slow wave sleep by influencing hypnogenic mechanisms of the lower brain stem. Fast EEG patterns produced by diazepam and partially by flurazepam seemed unrelated to the sleep-inducing mechanisms while the activating mesencephalic system appeared to be involved.

Animals↗
PubMed1982

Mesencephalic and bulbar reticular formation influences on somatosensory transmission through the thalamus.

The influence of the brain stem reticular formation (RF) on transfer of somatosensory information has been studied in intact cats and in cats with a chronic hemisection of the brain stem at the pretrigeminal level. An air-jet applied to the hairy skin receptive field evoked the discharge of thalamocortical relay cells in nucleus ventralis postero-lateralis, extracellularly recorded. Conditioning stimuli were brief trains of electrical pulses to mesencephalic (MRF) and bulbar (BRF) reticular formation. In intact cats both MRF and BRF induced in a small percentage of cells slight facilitation or inhibition of evoked discharge. In pretrigeminal cats MRF stimulation increased the probability of discharge in response to peripheral stimuli, whereas BRF stimulation induced a striking decrease in evoked firing in a great percentage of neurones. It is suggested that RF activation can decrease the incoming peripheral volley by means of its caudalmost part, while it is able to enhance thalamic response by way of the more rostral structures.

Afferent Pathways↗
PubMed1982

Effects of a new benzodiazepine hypnotic (quazepam--SCH 16134) on EEG synchronization and sleep-inducing mechanisms in cats.

The sleep-inducing properties of a new benzodiazepine hypnotic (quazepam--SCH 16134) were evaluated in cats with transection at different levels of the brain stem structure. Effects observed after administration of doses ranging from 0.12 and 1 mg/kg given intravenously were compared with those of pentobarbital. In the encéphale isolé small doses of quazepam induced or increased the synchronized periods. The desynchronized electroencephalogram (EEG) pattern of midpontine pretrigeminal preparations was not modified by these small doses. Only larger doses induced a fast neocortical activity of high amplitude. In midpontine pretrigeminal hemisection the synchronization occurred exclusively or predominantly in the hemisphere contralateral to the lesion. In the cerveau isolé, quazepam did not influence the typical synchronized EEG pattern. The arousal threshold after mesencephalic and physiological stimulation was raised only in encéphale isolé animals. Pentobarbital provoked sustained synchronization in all preparations with a pattern quite different from that of the benzodiazepine. These results suggest that quazepam may act through facilitation of the EEG-synchronizing mechanisms localized in the lower brain stem which are involved in physiological EEG-synchronizing and sleep-inducing processes.

Acoustic Stimulation↗