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Biomedical subjects

G Franchi

Publications and source records attributed to G Franchi.

At least 55 records · Page 3Linked to original sources
PubMed1993

Commercial kits for 1,25-dihydroxyvitamin D compared with a liquid-chromatographic assay.

Three commercially available kits for 1,25-dihydroxyvitamin D [1,25(OH)2D] determination were compared with a liquid-chromatographic method. Serum samples were analyzed for 1,25(OH)2D from 70 healthy subjects (age 2.2-17.5 years; 35 males, 35 females), some (n = 5) given orally high vitamin D3 doses. In addition, 1,25(OH)2D was measured in 28 patients with untreated diseases associated with low (n = 16) or high (n = 12) serum concentrations of the hormone. The results showed that the commercial kits were sufficiently accurate with respect to the comparison method and suitable for routine clinical work.

Adolescent↗
PubMed1992

Approach to the sterilization with gamma rays of a drug. Note I: Treatment technique and effects at zero time.

Authors, considering a possible use of the sterilizing treatment with gamma rays for the productive process of a drug, performed a series of practical treatment tests. To this purpose, they used a single molecule, stable in time and with an easy analytical approach. The examined active principle is the injectable salt of acetylcarnitine chloride. For tests, they used irradiating doses by 2.5-5.0-7.5 Mrads in order to point out the process possible effects. The treatment, even at highest dosages, did not show damages to the molecule that could prevent from going on with the investigation.

Acetylcarnitine↗
PubMed1992

[The effect of a territorial health emergency service on the delay in the hospitalization of patients with an acute myocardial infarct].

In July 1987 a prehospital emergency medical service (EMS) was activated in Verona (Italy) and a broad educational campaign was introduced. Prehospital care is delivered by emergency physicians and/or qualified nursing staff, who travel by ambulance or helicopter and have radio contact with the hospital alarm centre. During a 1-year period before the activation of the EMS, 476 patients with acute myocardial infarction (AMI) were admitted to the coronary care unit (CCU) of Verona, with a median delay time of 4 hours. In the period between July 1990 and June 1991, 412 patients were admitted, with a median delay time of 3 hours. Age, gender, previous AMI and infarct location were not related to delay time. In the second period, 34% patients used the EMS, while 66% used their own transport. In patients who used the EMS, median delay time was 2 hours (1 hour and 20 min shorter, p < 0.01, than in patients who did not). The time between symptoms onset and reaching the decision that medical care should be sought (1 hour and 18 min) was the longest component of the total delay time. The time from EMS call to hospital arrival was 25 min and the time which elapsed in the Emergency Department before reaching the CCU was 15 min. In these patients, decision time and Emergency Department time were significantly shorter (p < 0.01) than in patients who did not use the EMS. We conclude that the EMS is effective in reducing delay time in patients with AMI.

Aged↗
PubMed1991

[Headache caused by analgesic and/or ergotamine abuse].

Headache induced by ergotamine-abuse was described 40 years ago. More recently there is ample evidence suggesting that chronic headache may also be provoked by analgesic abuse. A recent Classification of the International Headache Society has defined this kind of headache as an autonomous disease. It consists in a daily chronic headache with paroxysmal attacks associated with daily or almost daily assumption of analgesics and/or ergotamine. It is debated whether the term "abuse" or "dependence" is correct. Almost 5% of patients of the Headache Centres in Italy were found to be drug abusers. Most of these patients originally suffered from migraine. The therapeutic approach consists in hospitalization, withdrawal of analgesics and/or ergotamine, treatment of the withdrawal headache (which appears within 48 hours and lasts even 1-2 weeks) and finally in a prophylactic therapy. Although several treatments have been suggested for the abstinence syndrome, only fluid replacement, antiemetics, hypnotic-sedative drugs and rarely mild analgesics are necessary. A review of the literature shows the following success rates in the relief of the headache: above 50% relief in more than 60% of patients within a follow up period of 1 to 3.5 years as mean. Even if caffeine and barbiturates, which are often contained in the analgesic and ergotamine preparations, might be considered the cause of the abuse and withdrawal syndrome, they don't seem to play a fundamental role in this syndrome. An impairment of the central antinociceptive system was hypothesized to be involved in the pathogenesis of the headache associated with analgesic and/or ergotamine abuse. Recently there has been evidence of a possible hyposensitivity of the adrenergic and serotoninergic receptors of the central nervous system. It is still to be proved whether drug abuse is the cause or the consequence of the headache chronicization. The remarkable improvement of headache after analgesic withdrawal suggests a causal factor.

Analgesics↗
PubMed1990

Low threshold unilateral and bilateral facial movements evoked by motor cortex stimulation in cats.

Organizational features of the ipsilateral representation in the cat face motor cortex were investigated by using the technique of intracortical microstimulation (less than 30 microA). In 4 intact animals, 61 efferent zones controlling facial muscles were identified. They were devoted to contralateral muscles (contralateral efferent zones; n = 35), ipsilateral muscles (ipsilateral efferent zones; n = 8) or symmetrical muscles of both sides (bilateral efferent zones; n = 18). Contralateral efferent zones were found within both the rostral part of the coronal gyrus and the lateral bank of the presylvian sulcus, whereas ipsilateral and bilateral efferent zones were exclusively localized to the rostromedial region of the face motor cortex. Movement thresholds proved to be lowest at the contralateral efferent zones and highest at the ipsilateral efferent zones, with intermediate values at the bilateral efferent zones. Latencies of suprathreshold EMG responses evoked from contralateral and ipsilateral efferent zones were the shortest and the longest, respectively; intermediate values were found upon stimulation of sites from bilateral efferent zones. The efferent zones identified in 3 lesioned animals (two cats with contralateral motor cortex ablation and one cat with transection of the rostral two thirds of the corpus callosum) were contralateral (n = 14), bilateral (n = 13), and ipsilateral (n = 9). Mean thresholds of effective sites from bilateral and ipsilateral efferent zones in lesioned preparations were not significantly higher than those in intact animals. This would thus suggest that extracallosal pathways may account for ipsilateral responses.

Animals↗
PubMed1990

[Intra- and perioperative arrhythmia and ischemic signals in myocardial revascularization patients].

In order to evaluate perioperative electrical cardiac disturbances and ST segment changes, 42 patients (38 M, 4 F, aged 57 +/- 6 ys) were studied using 24-hour Holter monitoring before, during and after coronary bypass surgery. In the 4-6 hours before cardioplegic arrest, 38% of patients had ST segment changes. No patient and malignant arrhythmias. The injection of cold cardioplegic solution was followed by bradycardia, ventricular tachycardia, ventricular fibrillation and isoelectric line within 2-4 minutes. After aortic declamping, 30 patients were defibrillated. Impulse formation and conduction disturbances, found in 55% of patients, solved themselves in 1 to 60 minutes. Bundle branch block continued in just 4 cases. A total of 59% of patients had ST segment elevation for 14 +/- 14 minutes and 19% had ST segment depression for 19 +/- 20 minutes. Successive transient ST segment changes were detected in 38% of patients. Sustained ventricular tachycardia occurred during 2 ischemic episodes. Impulse formation and conduction disturbances were not related to the duration of cardiac arrest or ventricular fibrillation, but were more frequent and lasted longer in patients with incomplete revascularization. Transient ST segment depression far from aortic declamping correlated with preclamping ischemia. Transient ST segment elevation correlated with incomplete revascularization. We concluded that ECG signs of intraoperative damage were reversible. Moreover, perioperative transitory ischemia was frequent but could be prevented by coronary active drug administration. On the other hand incomplete revascularization was associated with electrical disturbances and ischemia.

Aged↗
PubMed1989

The functional development of input-output relationships in the rostral portion of the corpus callosum in the kitten.

Microstimulation of the rostral portion of the corpus callosum (CC) was carried out on 21 awake kittens ranging in age from 45 to 105 days to determine the age at which motor responses first appeared and that at which they assumed functional adult-like properties. Motor responses to microstimulation first appeared over an interval ranging from 78-86 days postnatally. As in adults, they consisted of discrete, well-localized contractions of shoulder, whisker, and eyelid muscles according to the stimulated sites. In the first days after their appearance, motor responses differed markedly from those in adults because: (a) they exhibited higher thresholds; (b) they did not faithfully follow pulse trains delivered at 10 s intervals; (c) they had variable and longer latencies. Thereafter, motor responses gradually became stable, faithfully followed suprathreshold stimulation delivered at 0.1/s frequency, and acquired lower thresholds and shorter latencies, until they exhibited adult-like properties at 93-100 days of age. Single-unit recordings were obtained from 138 fibres isolated in the same callosal region submitted to microstimulation in order to study the response properties of the callosal fibres to somatic stimuli in immature animals. On the basis of their reactivity to peripheral stimulation, fibres were classified into three main types: (1) unreactive units (58 fibres), which could not be driven by somatic stimuli. (2) Adult-like units (55 fibres), which were readily driven by somatic stimuli and were endowed with fixed and small receptive fields (RFs) indistinguishable from those of adults. (3) Immature units (25 fibres), which were unsteadily driven by somatic stimuli applied over large areas at the periphery. Neither the RFs nor the adequate stimuli could be reliably determined. This type of units was not found in the adult cat (Spidalieri et al. 1985). The proportion of unreactive units was the highest before the appearance of motor responses and gradually decreased, approaching the adult level after attaining adult-like motor responses. Conversely, the proportion of adult-like units was lowest before the appearance of motor responses and gradually increased, approaching the adult level after motor responses had acquired adult-like properties.

Action Potentials↗
PubMed1989

Reduced serotonin vascular sensitivity in ergotamine abusers.

The action of ergotamine on the 5-hydroxytryptamine (5-HT) venous sensitivity was studied in ergotamine abuser and non-abuser migraine patients. Ergotamine abusers showed reduced 5-HT hand vein contraction during abuse, compared to seven days after ergotamine withdrawal. In non-ergotamine users, the 5-HT venoconstriction was not significantly modified 12 h after a single intramuscular ergotamine (0.25 mg) administration. Even the administration of ergotamine locally into the vein did not change the venospasm of 5-HT given acutely in the same vein. Therefore, it seems that the 5-HT antagonism does not contribute to the therapeutic effect of ergotamine during the migraine attack. Moreover, the reduced 5-HT responsiveness during ergotamine abuse may possibly be compatible with the chronic headache present in some abusers, the withdrawal headache attacks and the abuse itself.

Adult↗
PubMed1989

[Functional properties of efferent zones of the motor cortex which project to ipsilateral and contralateral face muscles].

In both intact (4 animals) and lesioned (2 preparations with contralateral motor cortex ablation and 1 animal with transection of the rostral two thirds of the corpus callosum) cats, three different types of efferent zones were identified in the face motor cortex by the technique of microstimulation: contralateral, ipsilateral and bilateral efferent zones. The three types of efferent zones had different organizational features such as location, thresholds of effective sites and latencies of motor responses. Mean thresholds of effective sites from ipsilateral and bilateral efferent zones in lesioned animals were not significantly higher than those in intact preparations. In both intact and lesioned animals, neurons endowed with contralateral, bilateral and ipsilateral receptive fields were isolated from the three types of efferent zones.

Animals↗
PubMed1989

[Densitometric control of the degradation products of vitamin B1 and calculating activation factors].

The authors perfect a TLC method with densitometric detection for the determination of vitamin B1 in the presence of its hydrolytic and oxidation products. The decomposition process and the proportions of products formed in the ampoules under different conditions of temperature/time treatment are also investigated and the activation factors (z and FO) of thiamine thermical decomposition, for their application in sterilization processes.

Densitometry↗
PubMed1988

Effects of calcium antagonists on serotonin and noradrenaline venoconstriction in humans.

The activity of some calcium antagonists on 5-hydroxytryptamine (5HT) and noradrenaline-induced venoconstriction has been evaluated in humans. Oral doses of nimodipine, 30 mg, and nifedipine, 10 mg, but not of verapamil, 80 mg, and flunarizine, 10 mg, inhibit 5HT-induced venoconstriction of the dorsal hand vein. Nimodipine, but not verapamil and flunarizine, inhibit noradrenaline-induced venoconstriction as well. Verapamil, locally administered into the hand vein, inhibits 5HT and noradrenaline-induced venoconstriction. These results suggest that only calcium antagonists of the dihydropyridine type have antivenoconstrictive activity in the hand vein at oral clinical doses, whereas verapamil is active only if administered by the intravenous route, which probably produces local plasma concentrations higher than those reached with the oral clinical doses.

Administration, Oral↗
PubMed1987

Somatostatin: peripheral venoconstrictive activity and interaction with monoamines in man.

The mechanism of somatostatin venoconstriction and tachyphylaxis in the human hand vein in vivo has been investigated. No cross-tachyphylaxis was observed between somatostatin and 5-hydroxytryptamine, noradrenaline, adrenaline, dopamine or tyramine-induced venoconstriction. Somatostatin potentiates the venoconstrictive activity of noradrenaline, adrenaline and dopamine, but not that of 5-hydroxytryptamine and tyramine. Phentolamine antagonizes the somatostatin-induced venoconstriction, whereas methysergide, haloperidol and morphine do not. It is suggested that somatostatin could act on specific receptors in the hand vein, but the mechanism of somatostatin venoconstriction and interaction with vasoactive monoamines remains to be defined.

Adult↗
PubMed1986

Motor responses mediated by orthodromic and antidromic activation of the rostral portion of the cat corpus callosum.

The effects of microstimulation of the rostral portion of the corpus callosum (CC) were examined in seven chronic cats submitted to either unilateral motor cortex ablation (5 preparations) or transection of the rostral two thirds of the CC (2 preparations) in order to identify the routes (ortho- or antidromic) followed by callosal impulses to provoke the motor effects. As in intact animals, motor responses in lesioned preparations consisted of very localized contractions of shoulder, whisker, or eyelid muscles, according to the stimulated sites. Unlike intact animals in which motor responses upon CC microstimulation were bilateral and symmetrical (Spidalieri and Guandalini 1983), in lesioned preparations they appeared contralaterally to the emitting hemisphere, i.e., they were contralateral to the stimulated callosal stump (split-brain preparations) and ipsilateral to the side of the cortical lesion (preparations with unilateral motor cortex ablation), regardless of the current intensity applied (up to a maximum of 50 microA). The unilateral motor responses occurred by the first day after lesion and persisted for the duration of the experiments which lasted to a month or more. Since orthograde degeneration of callosal fibres deprived of their somata has been shown by previous anatomical studies to be complete within 11 days after lesion, these results indicate that selective antidromic activation of callosal fibres is capable of eliciting motor responses. Thresholds for the motor effects in lesioned preparations proved to be from 1.3 to 3.9 (mean, = 2.4 +/- 0.7 SD) times higher than those found before motor cortex ablation. By 18 days after lesion a decrease of threshold currents for the motor responses was observed ranging from 6 to 37% (mean, = 24.2 +/- 13.6 SD), depending on the stimulated sites, relative to values previously found. The shortest train duration and the lowest frequency for minimum threshold were longer (40 vs. 30 ms) and higher (400 vs. 300 Hz), respectively in lesioned preparations than in intact controls. Moreover, a decrease in train duration or frequency provoked larger threshold increases in lesioned preparations than those observed in intact animals. As a whole, these results suggest that in intact animals the motor effects are also mediated by orthodromic callosal volleys.

Animals↗