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Biomedical subjects

A Sciacca

Publications and source records attributed to A Sciacca.

At least 19 recordsLinked to original sources

Effects of TRH-T on spinal motoneurones in man.

The effect of thyrotropin-releasing hormone tartrate (TRH-T) on the decrease in H Max/M Max ratio, an index of the spinal motoneurone pool, induced by haloperidol, was studied in 15 healthy volunteers. In all subjects, the H response was examined by an electromyographic apparatus. The values were expressed as H Max/M Max ratio, that gives an index of excitability of the spinal motoneurone pool. It was found that the mean H Max/M Max ratio value significantly decreased after haloperidol administration, but this effect was completely reversed by the injection of TRH-T. This finding suggests that the peptide may modulate motoneurone functions.

Adult

[Ventricular late potentials in hypertrophic cardiomyopathy: personal contribution and analysis of the literature].

BACKGROUND: Patients with hypertrophic cardiomyopathy are at increased risk of sudden death. Recently it has been investigated whether late potentials can be useful markers of that risk in such patients, with discordant results. The aim of our study was to detect a correlation, if any, between late potentials, ventricular tachycardia and the hypertrophy extension. METHODS: Twenty-five patients were enrolled, 19 males and 6 females, mean age 40.40 +/- 15.02 years. Each underwent 24h Holter monitoring, averaged ECG, M-Mode and 2-D Echo. The hypertrophy was considered extensive (septum and free wall) or non extensive (septum and/or apex). RESULTS: Late potentials of a mean duration of 37 +/- 14.83 ms were recorded in 5/7 patients with documented ventricular tachycardia vs in none of the non tachycardia group. Sensibility was 100%, specificity 71% and predictive value 100%. Late potentials were present in 8.3% of patients with non extensive and in 30.8% of patients with extensive hypertrophy (p = NS). CONCLUSIONS: From our data it seems that extensive hypertrophy is present in about half of patients with hypertrophic cardiomyopathy, and this roughly correlates with a more frequent ventricular tachycardia and with late potentials. Furthermore, late potentials are strictly related to the incidence of ventricular tachycardia in this disease, just as in ischemic heart disease or in idiopathic dilated cardiomyopathy. The small number of our cases may not be sufficient to reach a significant statistical correlation between late potentials and hypertrophy, but we believe that the trend is very promising.

Action Potentials

Neopterin as a marker of C hepatitis in thalassaemia major.

The authors studied serum neopterin in 106 patients with beta thalassaemia major. A good correlation was found between neopterin values and glutamic pyruvic transaminase (GPT) mean values of the last 6 months, whereas no correlation was found between neopterin values and some siderosis indexes (iron/body weight, total accumulated iron). A statistically significant correlation was found between neopterin values (greater than 10 nM/L vs. less than 10 nM/L) and histological liver findings (chronic hepatitis vs. siderosis). Neopterin values were also statistically different between splenectomized and not splenectomized patients. Moreover serum neopterin was higher in HCV-Ab positive than in HCV-Ab negative patients, and 91.6% of the HCV-Ab positive group also showed histological signs of chronic hepatitis. These data suggest that increased serum neopterin might help to identify chronic C hepatitis in thalassaemic patients.

Adolescent

Immune response of subjects at high risk of hepatitis B to a new genetically engineered hepatitis B vaccine administered in low doses by the intradermal route.

Fifty-eight subjects at high risk for hepatitis B were vaccinated with hepatitis B vaccine prepared by a DNA recombinant technique (Engerix B- Smith-Kline Biologicals) by the intradermal route with low doses (5 microgr) at 0, 15, 30 and 45 days on the volar surface of the arms. A positive immune response (100%) was found in all children (5 affected by thalassemia, 5 affected by sickle cell anaemia, 9 affected by neurological handicaps) and in all healthy medical staff. None showed side-effects and the small pigmented macula following vaccination disappeared after a few months. Since the World Health Organization proposed a program of mass vaccination in highly endemic areas for hepatitis B, the authors suggest that the use of the new engineered vaccine in low doses by the intradermal route could represent an effective strategy to realize this project.

Adolescent

Intradermal hepatitis B vaccination in thalassaemia.

Fifty six children with thalassaemia, and 118 healthy subjects, who had all been immunised with an intramuscular injection of hepatitis B vaccine (HB-VAX) into the deltoid area three years previously, were given booster doses intradermally. All responders (good = hepatitis B surface (HBs) antibody titre greater than or equal to 10 U/l; poor = HBs antibody titre less than 10 U/l) showed pronounced increase in anti-HBs titre, in many cases above 1000 U/l. We also found positive HBs antibody response after further doses (two to four) at intervals of 15 days in non-responders (those patients who formerly had shown no HBs antibody titre after the conventional schedule of vaccination). The humoral response was always preceded by a delayed tissue hypersensitivity reaction. In conclusion, vaccine against hepatitis B virus given in low doses intradermally produces an effective immune response; it is a useful method of enhancing the antibody response in exposed patients, and of vaccinating those who do not respond initially.

Antibody Formation

Late potentials in idiopathic dilated cardiomyopathy.

Twenty-five patients with idiopathic dilated cardiomiopathy were investigated in order to evaluate the role of late ventricular potentials as possible markers of ventricular tachycardia or sudden cardiac death. Holter monitoring showed ventricular tachycardia in 9 patients (group A) all of whom had late ventricular potentials, (mean +/- SD length 37.22 +/- 15.83 ms and mean +/- SD voltage 5.62 +/- 2.78 microV). Mean +/- SD ejection fraction in this group was 20 +/- 9.39%. In 16 patients (group B), without ventricular tachycardia, means +/- SD ejection fraction 27.5 +/- 8.17%; late ventricular potentials were recorded in 2 patients. During the follow-up period (means +/- SD 11.53 +/- 7.19 months), 3 patients underwent heart transplantation, 2 patients underwent pace-maker implantation and 2 patients from the ventricular tachycardia group died one from sudden cardiac death and the other from progressive heart failure. No significant differences were found in the ejection fraction either between the ventricular tachycardia and the non-ventricular tachycardia group, or between the late ventricular potentials and the non-late ventricular potential groups. Negative data were also obtained when we tried to find a correlation between the ejection fraction and late ventricular potential length and/or voltage. Good results were observed with regard to sensitivity (100%), specificity (87%) and predictive accuracy (81%) but follow-up data did not specify a definite prognostic value for late ventricular potentials. The Authors conclude that late ventricular potentials are markers of patients with idiopathic dilated cardiomyopathy who are prone to ventricular tachycardia. However, the role of late ventricular potentials in sudden cardiac death is still uncertain.

Adolescent

Heart transplant rejection detected by signal averaged QRS analysis. Preliminary results.

Detailed QRS wave analysis from the limb leads of the surface high resolution electrocardiograms recorded in five cyclosporine-treated heart transplant recipients gave good correlation with the corresponding results of endomyocardial biopsy. That is when the result of the biopsies has identified the presence of rejection, a concomitant (p = 0.001) variation in some parameters of the QRS has been observed. The reproducibility of such parameters (established by means of the correlation coefficient r) gave r values ranging from 0.6 up to 0.93. The correlation regarded parameters analyzed both in time and frequency domain. Biopsy results were divided into two classes on the basis of the presence or absence of rejection. The most significant parameters obtained from high-frequency (25-300 Hz) ECGs within a few hours of each biopsy were: a) the total high-frequency voltage amplitude Vt of the QRS and the voltage amplitude of its initial Vi and middle thirds Vm; b) the peak voltage amplitude Vp of the QRS; c) the QRS duration L; d) the integrated voltage time product I of the QRS; e) three mean voltage amplitudes V5, V6, V7, of the power spectral density constructed on the basis of the 512-point fast Fourier transform applied on each recording. The above mentioned parameters appear to be useful in predicting the biopsy result in terms of the presence or absence of rejection.

Adolescent

Analysis of high-resolution atrial activation: report on 403 cases.

The findings of a study carried out on a sample of 403 P waves, selected over the 50 to 300 Hz frequency range, by a portable microcomputer system capable of averaging 512 P waves, are reported. Detailed analysis of P waves was attempted in healthy subjects and in patients affected by pathologic processes where atrial involvement had been observed. An attempt was made to individualize P wave parameters which may be associated with these pathologic conditions. On each atrial signal a 512-point fast Fourier transform was used. The original sample was divided into 18 classes, and the mean values of some parameters of each class were computed. The results of fast Fourier transform computing and of the mean values of parameters for both patients and healthy subjects show two different behaviors with respect to the amplitude-frequency relationships and mean peak-to-peak amplitude, respectively. The present results indicate that this technique may be useful for further detailed analysis of P waves.

Adult

Therapeutic efficacy of ketanserin, a selective antagonist of the serotonin (5-HT2) receptors, in primary and secondary Raynaud's phenomenon.

Fourteen ambulatory and hospitalized patients with primary and secondary Raynaud's phenomenon have been examined before and after a thirty-one-day therapeutic trial. The treatment was conducted in two cycles. The first one lasted ten days, during which placebo was administered. The second cycle lasted three weeks, during which ketanserin, a selective antagonist of 5-hydroxytryptamine (5-HT2) receptors, was administered. The therapeutic effect consisted of the complete healing of digital ulcers in 4 of 5 patients and a considerable decrease in the number, length, and severity of daily attacks. To evaluate the digital blood flow, each patient was submitted to a medical dynamic telethermographic test. This, after the cooling test, demonstrated an average decrease of twenty minutes in the time necessary to reestablish basal thermal conditions (T') at the end of an adequate period of therapy using optimal doses of the drug. The authors affirm that orally administered ketanserin has a beneficial effect and can be well tolerated in subjects with Raynaud's phenomenon.

Adult