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Biomedical subjects

F Conti

Publications and source records attributed to F Conti.

At least 199 records · Page 11Linked to original sources
PubMed1982

Axonal branching in the periaqueductal gray projections to the thalamus: a fluorescent retrograde double-labeling study in the cat.

The double-labeling technique based on the retrograde axonal transport of fluorescent tracers (Evans blue, EB; Fast blue, FB; Nuclear yellow, NY) was used in the cat in order to investigate the occurrence of axonal branching in the periaqueductal gray (PAG) projections to some thalamic nuclei (n. ventralis postero-lateralis, VPL; n. ventralis postero-medialis, VPM; n. parafascicularis, Pf). In a first group of cats, FB and EB were injected, respectively, within the right and left VPM. In another two groups of cats, FB injections into Pf were combined with either EB or NY injections within VPL or VPM. Double-labeled neurons were found within the PAG only in the animals of the first group. The present results show that some PAG neurons project bilaterally to VPM by means of axons collaterals.

Animals↗
PubMed1982

Periaqueductal grey projection to the ventrobasal complex in the cat: an horseradish peroxidase study.

Horseradish peroxidase (HRP) was injected within the thalamic ventrobasal complex of 14 cats. The aim was to ascertain whether the periaqueductal grey matter (PAG) sends fibres to this complex. Retrogradely labelled cells were found within the PAG following HRP delivery either in the nucleus ventralis posterolateralis (VPL) or ventralis posteromedialis (VPM). PAG-VPL projection is only ipsilateral and arises mainly from lateral PAG, PAG-VPM projection is bilateral and originates from latero-ventral regions of the central grey. The hypothesis that PAG might control the activity of ventrobasal nociceptive neurones is proposed.

Afferent Pathways↗
PubMed1981

[Anatomic demonstration of axon collaterals of the periaqueductal gray formation and the ventrobasal thalamic nuclei of both sides].

In 4 adult cats the left and right thalamic nucleus VPM have been injected with fluorescent substances, Evans Blue and Fast Blue in order to ascertain whether PAG cells send bifurcated axons to the thalamic nuclei of both sides. The results confirm previous studies on the PAG-VPM connections performed in this laboratory by using HRP technique, and demonstrate, within the PAG, the presence of a good number of double-labeled cells (stained by both E.B. and F.B.) intermingled with single-labeled cells, stained either by E.B. or F.B. The double-labeled cells might represent the anatomical substrate of a possible bilateral analgesic mechanism in the trigeminal region.

Animals↗
PubMed1981

Reversible electrical breakdown of squid giant axon membrane.

Charge pulse relaxation experiments were performed on squid giant axon. In the low voltage range, the initial voltage across squid axon membrane was a linear function of the injected charge. For voltages of the order of 1 V this relationship between injected charge and voltage across the membrane changes abruptly. Because of a high conductance state caused by these large electric fields the voltage across the membrane cannot be made large enough to exceed a critical value, Vc, defined as the breakdown voltage, Vc has for squid axon membrane a value of 1.1 V at 12 degrees C. During breakdown the specific membrane conductance exceeds 1 S. cm-2. Electrical breakdown produced by charge pulses of few microseconds duration have no influence on the excitability of the squid axon membrane. The resealing process of the membrane is so fast that a depolarizing breakdown is followed by the falling phase of a normal action potential. Thus, membrane voltages close to Vc open the sodium channels in few microseconds, but do not produce a decrease of the time constant of potassium activation large enough to cause the opening of a significant percentage of channels in a time of about 10 mus. It is probable that the reversible electrical breakdown is mainly caused by mechanical instability produced by electrostriction of the membrane (electrochemical model), but the decrease in the Born energy for ion injection into the membrane, accompanying the decrease in membrane thickness, may play also an important role. Because of the high conductance of the membrane during breakdown it seems very likely that this results in pore formation.

Action Potentials↗
PubMed1981

[Pelviperineal recurrences in surgery of rectal carcinoma].

A series of pelviperineal recurrences after perineal-abdominal amputation of the rectum and after anterior resection is examined. Involvement of the rectal wall, the biological behaviour of the tumour, and lymphatic diffusion represent the main causes of recurrence. In some instances, the choice of anterior resection in the treatment of middle rectum carcinoma may constitute a risk factor.

Aged↗
PubMed1981

Electron spin resonance of growing normal and virus-transformed cells.

A g = 2.003 ESR signal, attributed to a free radical localized in HeLa cell nuclei and mitochondria but absent in membranes and cytoplasm, has been studied as a function of the culture growth cycle in normal (NRK and 3T3) and virus transformed (NRK/RSV and 3T3/SV40) cells. For both these cell pairs, the signal is higher during the "lag" stage and lower during the "growth" stage. The average specific intensity of the signal in normal cells is about twice that in virus-transformed cells. However, the maximal point of resonance during the lag state is higher in transformed cells than in normal ones. The lag stage in NRK and NRK/RSV cells is much longer than in 3T3 and 3T3/SV40 cells, while the maximal value of the g = 2.003 ESR signal occurs, early in the lag stage of 3T3 and 3T3/SV40 cells and late in the lag stage of NRK and NRK/RSV cells.

Animals↗
PubMed1981

Bioavailability of plafibride in healthy volunteers.

The pharmacokinetics of N-2-(p-chlorophenoxy)-isobutyryl-N'-morpholinomethylurea (plafibride, ITA 104) in rats, and its intestinal absorption, plasmatic biotransformation, urinary elimination and fecal excretion were previously studied. 1200 mg of plafibride orally were administered to 5 healthy volunteers and then the presence of the drug and its metabolites was studied in the serum. The presence of unchanged plafibride and clofibric acid was detected, whereas that of 2-(p-chlorophenoxy) isobutyrylurea was not. At the same time the platelet antiaggregating activity of plafibride was investigated in the 5 volunteers. In this study plafibride presented a good and long-lasting platelet antiaggregating activity.

Adult↗
PubMed1980

Single channel recordings of K+ currents in squid axons.

Ionic currents from individual K+ channels in squid axon membrane have been recorded. At hyperpolarizing membrane voltages, unit events occur as widely spaced rectangular pulses with short interruptions. The frequency of occurrence of the units increases strongly when the membrane is depolarized.

Animals↗