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Biomedical subjects

G Bini

Publications and source records attributed to G Bini.

31 records · Page 2Linked to original sources
PubMed1977

Selective Activation of peripheral nerve fibre groups of different diameter by triangular shaped stimulus pulses.

1. The differential block of cutaneous nerve fibres has been achieved with a simple method of electrical stimulation, employing a single pair of active electrodes. 2. The method allows the selective activation of 95% of small myelinated (delta) axons, without activation of the larger (beta) ones; and activation of unmyelinated (C) fibres, without A fibre activation. Asynchronous firing of myelinated axons was absent in the majority of the experiments. 3. The method employs triangularly shaped electrical pulses, with a steep rise front and a slow exponential decay. The outward flow of current at the cathode fires conducted impulses in both larger and smaller axons, and the inward flow inactivates differentially the conduction in the smaller ones. 4. The differential effect of anodal currents rests upon the greater internal conductance and greater conduction velocity of larger fibres. 5. The method has the advantage over the conventional polarization block of simpler surgical preparation, longer nerve survival and minimal latency distortion. However, it cannot be applied in experiments requiring physiological stimulation of peripheral receptors.

Action Potentials↗
PubMedDate not supplied

[Validity of the V/Q index in the monitoring of critical patients].

The Authors have controlled the validity of VQI to quantify pulmonary shunt (Qs/Qt). The survey involved (group A) patients who had undergone major surgery and (group B) patients hospitalized in ICU for cardiorespiratory failure. Four subgroups were identified in both the groups according to different values of SaO2. A good correlation, already described by Räsänen, was comproved in the groups and subgroups. However a progressive reduction of the coefficient of correlation from the lower to the higher values of SaO2 was noted. Finally the differences observed between group A and group B, are supposed to be dependent on a greater variability of haemoglobin, in the surgical group, in relation to the time of evaluation.

Analysis of Variance↗
PubMedDate not supplied

[Congenital analgesia].

The case of a 12 years old boy with a congenital anaesthesia covering all cutaneous and visceral districts is reported. There were no other neurological abnormalities apart a light mental retardation and loss of axon reflex after intradermal injection of hystamine. Notwithstanding this last finding a diagnosis of congenital indifference to pain was made. The differential diagnosis between indifference and insensitivity to pain is discussed.

Axons↗
PubMedDate not supplied

[Monocular ocular bobbing].

The ocular bobbing phenomenon consists of involuntary, abrupt, usually conjugate, brisk downward eye movements followed by a slow return to midposition; it is most often observed in cases of coma due to pontine vascular lesions. In the patient reported here, with a coma after basilar thrombosis, the movement was initially conjugate and subsequently limited to one eye, as described by SUSAC and coworkers under the heading "monocular bobbing" in 1970. The movement was increased in amplitude and frequency by labirintine caloric stimulation as well as by non specific manoeuvres like neck skin pinching and visual stimulation. Post-mortem examination showed a large ischaemic infarction of the pons, of the middle cerebellar peduncles and of the white matter of one cerebellar hemisphere.

Aged↗
PubMedDate not supplied

[Carcinogens in the urban environment of Italian cities: benzene and benzo(a)pyrenes].

In Italian urban areas air pollution from benzene and benzo(a)pyrene-B(a)P--is mostly caused by traffic. The concentration limits in the atmosphere fixed by Italian legislation up to December 31, 1998 expressed as annual means are 15 micrograms/m3 and 2.5 ng/m3 for benzene and B(a)P respectively and, starting from January 1, 1999, 10 micrograms/m3 and 1 ng/m3. In the city of Florence the concentrations detected and expressed as annual means of benzene and B(a)P in an area with heavy traffic (32.1 micrograms/m3 and 3.5 ng/m3), in a densely populated area (9.2 micrograms/m3 and 1.86 ng/m3), and in a city park (6.0 micrograms/m3 and 0.25 ng/m3), suggest a marked progressive reduction in the atmospheric levels of these chemicals with the distance from the main roads. The environmental data obtained from densely populated areas of a number of Italian cities (Firenze, Milano, Roma, Bologna, Bolzano, Pavia, Modena), the only ones that allow evaluation of the health risk, show benzene concentrations ranging from 6.0 to 11.3 micrograms/m3 and B(a)P levels, measured in heavy traffic areas, from 1.0 to 3.5 ng/m3 respectively (annual mean in 1996). The data obtained in the city of Florence show that the population is exposed weekly to average concentrations of 14.3 micrograms/m3 for benzene and 2.0 ng/m3 for B(a)P. These results suggest that, regarding benzene and B(a)P pollution, the situation in Florence is far from being critical but not such as to ensure that long-term exposure is without adverse effects.

Air Pollutants↗