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Biomedical subjects

G Bini

Publications and source records attributed to G Bini.

At least 19 recordsLinked to original sources
PubMed2002

Chest pain unit management of patients at low and not low-risk for coronary artery disease in the emergency department. A 5-year experience in the Florence area.

In this study, we screened a total of 6723 consecutive patients with chest pain and ECG non-diagnostic for acute myocardial infarction (AMI) on presentation to the emergency department (ED). The aim of the study was to avoid missed AMI, improve safe early discharge and reduce inappropriate coronary care unit (CCU) admission. Chest pain patients were triaged using a clinical chest pain score and managed in a chest pain unit (CPU). Patients with a low clinical chest pain score were considered at very 'low-risk' for cardiovascular events and discharged from the ED; patients with a high chest pain score were submitted to CPU management. Observation and titration of serum markers of myocardial injury were obtained up to 6 hours. Rest or stress myocardial scintigraphy (SPECT) was performed in patients > 40 years or with > or = 2 major coronary risk factors. Exercise Tolerance Test (ETT) or Stress-Echocardiogram (stress-Echo) were performed in younger patients or with < 2 coronary risk factor, or unable to exercise, respectively We discharged directly from the ED the majority of patients (4454; 66%): in this group there was only a 0.2% final diagnosis of coronary artery disease (CAD) at follow-up. The remaining 34% of patients, with non-diagnostic or normal ECG, were managed in the CPU. In this group, 1487 patients (representing 22% of the overall study group) were found positive for CAD, two-thirds because of delayed ECG or serum markers of myocardial injury, and one-third by Echo, SPECT or ETT. In conclusion, CPU based management allowed 22% early detection of myocardial ischaemia and 78% early discharge from the ED avoiding inappropriate CCU admission and optimizing the use of urgent angiography.

Aged↗
PubMed1998

[Subarachnoid hemorrhage and the heart].

Electrocardiographic abnormalities had been reported, in patients with subarachnoid hemorrhage, with variable percentage from 2% to 91%, according to several studies. The most common changes are T wave inversion, ST segment elevation or depression, QT prolongation, U waves, atrial flutter and fibrillation, ventricular fibrillation, supraventricular tachycardia, premature atrial and ventricular contractions. These findings occur within the first forty-eight hours after the onset of the symptoms; they usually are benign and transient. In a small percentage of cases generally in severe ESA, the ECG changes are associated with ventricular asynergy, coronary vasospasm or subendocardic necrosis. The arrhythmias could be produced either by autonomic discharges to the heart, during increased sympathetic activity due to ESA, or by a damage of cerebral areas with arrhythmogenic capacity. The importance of ECG abnormalities towards mortality and morbidity in patients with ESA has not yet been cleared; however, a careful monitoring is recommended to prevent severe cardiac complications and to obtain an indirect, further evaluation of the neurologic pathology.

Electrocardiography↗
PubMed1982

Analgesic activity of carprofen on human experimental dental pain.

1. The effects of an orally administered single dose of placebo, acetylsalicyclic acid (ASA) and (d,1)-6-chloro-a-methyl carbazole-2-acetic acid (carprofen) have been evaluated on an experimental pain model by electrical stimulation of dental pulp in man. 2. ASA and carprofen showed a significant analgesic action, while placebo was ineffective. 3. Analgesic activity of ASA and carprofen was similar. The two drugs were ineffective in modifying the pain threshold; on the contrary, the tolerance to the strongest painful sensation was significantly increased.

Adult↗
PubMed1981

Congenital absence of pain.

A 16-year-old boy had congenital absence of pain sensitivity and no impairment of other sensory modalities. Routine electrophysiologic investigation showed no abnormalities. The threshold and latency of electrically elicited corneal reflex and cortical potentials evoked by tooth pulp stimulation were normal, but suprathreshold electric stimulation of corneal mucosa and dental pulp, as well as electric stimulation of dorsal roots, did not elicit pain. The total CSF opioid activity was raised. However, naloxone hydrochloride administration failed to reverse the analgesia. The axon reflex to intradermal injection of histamine dihydrochloride was absent. Cutaneous nerve branches showed unspecific changes affecting part of unmyelinated axons. most of the unmyelinated as well as the myelinated axons were normal. We consider the case an example of congenital indifference to pain.

Adolescent↗
PubMed1981

Acute experimental dental pain: a technique for evaluating pain modulating procedures.

A simple method for bipolar electrical stimulation of the tooth pulp for evaluating pain modulating procedures is described. Stimulation selectivity has been studied by means of cortical evoked potentials before and after gum anaesthesia. Results obtained by constant current and constant voltage stimulation have been compared. Constant voltage stimulation has proved to be more stable in time. This technique is able to differentiate the analgesic effect of a single dose of i.v. lysine acetylsalicylate from saline. Threshold sensation was judged as painful by about half of the subjects.

Adult↗
PubMed1981

Cardiac rhythmicity of skin sympathetic activity recorded from peripheral nerves in man.

In previous microelectrode recordings of sympathetic impulse activity in human peripheral nerves a marked cardiac rhythmicity has been found in the spontaneous firing of vasoconstrictor neurones supplying the vascular bed of skeletal muscles. Evidence has been presented that this rhythmicity depends on a potent baroreflex control of these neurones which are significantly involved in blood pressure regulation. In contrast, no cardiac rhythmicity has previously been seen in the spontaneous firing of sympathetic fibres supplying vessels and sweat glands in the human skin. The present study shows that when strong sudomotor activity is induced in skin nerves by a rise in ambient temperature, the sudomotor impulses tend to occur in volleys time-locked to the cardiac cycle. A similar cardiac rhythmicity is not exhibited by the skin vasoconstrictor fibres which can be activated by lowering of the ambient temperature. Induced falls in blood pressure do not produce any baroreflex modulations of the sudomotor outflow, suggesting that the cardiac rhythmicity of the sudomotor impulses is mot dependent on the action of this reflex.

Adult↗
PubMed1980

Thermoregulatory and rhythm-generating mechanisms governing the sudomotor and vasoconstrictor outflow in human cutaneous nerves.

1. Recordings of multiunit sympathetic activity were made from human nerve fascicles supplying hairy and glabrous skin of the extremities in healthy subjects exposed to different ambient temperatures. Sudomotor and vasomotor events accompanying the neural activity were monitored by simultaneous recordings of electrodermal and pulse plethysmographic events (Pleth) in the neural innervation zones. 2. By exposing the subject to warm (43 degrees C) or cold (15 degrees C) environments, it was possible to obtain a selective activation of either the sudomotor or the vasoconstrictor neural system, respectively, with suppression of spontaneous activity in the other system. 3. Bursts of both vasoconstrictor and sudomotor nerve activity were found to occur at certain preferred intervals which were integer multiples of a period of about 0 . 6 sec (100 cycles/min). With high sudomotor or vasoconstrictor tone the 100 cycles/min rhythm was prominent but with decreasing tone slower subharmonic rhythms prevailed. Respiratory rhythms were also discerned as well as slower rhythms attributable to oscillatory tendencies in thermoregulatory servos. 4. Vasoconstrictor bursts had longer mean duration than sudomotor bursts, a finding attributed to a slower conduction velocity of vasoconstrictor as compared to sudomotor impulses. 5. With increasing incidence of bursts transient electrodermal or plethysmographic responses following individual bursts merged, and thus the fast neural rhythms were not discernible in either the electrodermal or Pleth traces. Given increments in firing rate of nerves produced less additional vasoconstriction at high than at low firing rates. The rhythm generating mechanisms may help to restrict rates of individual fibres to the low range which provides high gain in the neuroeffector transfer functions.

Action Potentials↗
PubMed1980

Regional similarities and differences in thermoregulatory vaso- and sudomotor tone.

1. Skin nerve sympathetic activity was recorded simultaneously from the following pairs of nerves: left and right median, median and peroneal, left and right peroneal, posterior cutaneous antebrachial and superficial radial, posterior cutaneous antebrachial and median. The recordings were performed on healthy subjects exposed to different ambient temperatures. Electrodermal responses and pulse plethysmograms were recorded from the neural innervation zones. 2. Vasoconstriction impulse bursts recorded simultaneously from the median and peroneal nerves during exposure to a cold environment showed a striking similarity with respect to the timing and strength of individual bursts. A similar strong correlation was observed also among sudomotor bursts recorded simultaneously from the posterior cutaneous antebrachial and superficial radial nerve during exposure to a warm environment. 3. On some occasions, such as during exposure to a moderately warm environment or emotional stress, a temporal correlation was also observed between vasoconstrictor bursts recorded from the median and sudomotor bursts recorded simultaneously from the posterior cutaneous antebrachial nerve. 4. The double nerve recordings provided evidence that in the distal glabrous skin areas reflex thermoregulatory functions are mainly executed via vasoconstrictor fibres whereas sudomotor fibres are brought into action only at relatively high temperature. On the contrary, in the hairy skin on the dorsal side of forearm and hand reflex thermoregulation is to a large extent executed via sudomotor fibres.

Action Potentials↗
PubMed1980

Corneal reflex elicited by electrical stimulation of the human cornea.

The corneal reflex can be elicited in humans by electrical stimulation of the cornea. This method is harmless and allows precise quantification of the reflex response. In 18 patients with trigeminal lesions, the reflex was abolished or significantly altered on the diseased side in all cases. Measurement of the threshold is the most significant characteristic.

Adult↗
PubMed1979

[Multielectronic computerized EMG: technical notes on the recording and parallel off-line elaboration].

A Multielectrodic EMG analysis program is developing. The purpose is to get as short as possible the main EMG parameters (amplitude, duration, frequency) of most motor units, and to reach an estimation of the anatomical extent of single units. According to the muscle extent a variable number of electrodes are inserted crosswise the fibers. EMG signals are simultaneously recorded on a multichannel AMPEX FR1300 and then off-line processed by a 21MX HP minicomputer connected with a 5Mbytes disc drive. Some technical problems had to be solved:channel amplification adjustment to avoid any difference among preamplifiers calibration and filtering, severe hum filtering of main power that is specially strong in nultielectrodic recording systems, the need of sampling at the same Nyquist time the signals of different channels. The computer is instructed to identify the "sinchronous" units i.e. the motor units recorded from more than one channel. These motor units are detected, counted and deleted from all the channels, except the one where they show the maximum amplitude. The percentage of these sinchronous units depends upon the interelectrodic distance and their anatomical area, thus it can support an evaluation of motor unit anatomical spread.

Computers↗