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Biomedical subjects

R Perini

Publications and source records attributed to R Perini.

30 records · Page 2Linked to original sources
PubMed1989

Changes of muscular sound during sustained isometric contraction up to exhaustion.

The sound (SMG) generated by the biceps muscle during isometric exercise at 20, 40, 60, and 80% of maximum voluntary contraction (MVC) up to exhaustion has been recorded by a contact transducer and integrated (iSMG), together with the surface electromyogram (EMG) in eight young untrained men. At the onset of exercise, iSMG and integrated surface EMG (iEMG) amplitude increased linearly with exercise. iSMG remained constant for 253 +/- 73 (SD), 45 +/- 16, 21 +/- 5, and 0 s at the four levels of contraction. Then iSMG increased linearly at 20% MVC, fluctuated at 40% MVC, and decreased exponentially at 60 and 80% MVC. iSMG exhaustion-to-onset ratio was 5.0 at 20%, 1.0 at 40%, and 0.2 at 60 and 80% MVC. On the contrary, independently of exercise intensity, iEMG increased with time, being 1.4 higher at exhaustion than at the onset. The nonunivocal iSMG changes with time and effort of exercise suggest that the sound may be a useful tool to acquire different information to EMG and output force during muscle contraction up to fatigue.

Adult↗
PubMed1988

Plasma catecholamines and heart rate at the beginning of muscular exercise in man.

The relationship between the time course of heart rate and venous blood norepinephrine (NE) and epinephrine (E) concentrations was studied in 7 sedentary young men before and during 3 bicycle exercises of 5 min each (respectively 23 +/- 2.8%, 45 +/- 2.6% and 65 +/- 2.4% VO2max, mean +/- SE). During the low level exercise the change in heart rate is monoexponential (tau = 5.7 +/- 1.2 s) and no increment above the resting level of NE (delta NE) or of E (delta E) occurs. At the medium and highest intensity of exercise: a) the change in heart rate is biexponential, tau for the fast and the slow component averaging about 3 and 80 s respectively; b) delta NE (but not delta E) increases continuously with time of exercise; c) at the 5th min of exercise heart rate increments are related to delta NE; d) between 20 s and 5 min, at corresponding sampling times, the heart rate of the slow component is linearly related to delta NE. At exercise levels higher than 33% VO2max the increase in heart rate described by the slow component of the biexponential kinetic could be due to an augmented sympathetic activity revealed by increased NE blood levels.

Adult↗
PubMed1988

Spectral analysis of muscular sound at low and high contraction level.

The activated muscle generates a low frequency rumbling noise, which is known as the Sound-MyoGram (SMG). Spectral analysis of the SMG is carried out in this work, in order to: (i) check the adequacy of both the Fast Fourier Transform (FFT) and the Maximum Entropy Spectrum Estimation (MESE). Because it is a well known technique, the FFT method is only briefly described, while the philosophy of the MESE method is given in more detail and completed with a description of the recursive algorithm; (ii) select a frequency parameter suitable to describe the SMG. For this purpose two well-defined physiological conditions (20% and 80% Maximal Voluntary Contraction) have been adopted in order to provide a safe reference for the interpretation of the findings. The results show that: (a) both FFT and MESE are adequate to estimate the SMG Power Spectrum; (b) both the mean and the median frequency are suitable parameters, the mean frequency being the more favourable one; (c) the SMG Power Spectrum is a promising tool to study the muscle activation modalities.

Adult↗
PubMed1986

Intravenous immunoglobulin in immune neutropenia.

Three patients with immune neutropenia successfully treated with high dose intravenous IgG (IV IgG) are described. In the first case, the neutropenia had not responded to standard steroid therapy; in the second case, very high doses of steroids were required in order to obtain and maintain remission. In the last case, the steroids were contraindicated because of an underlying immunologic disorder. We suggest that these 3 forms of immune neutropenia might be a good indication for IV IgG treatment.

Adolescent↗
PubMed1984

Effect of phototherapy on the physiologic cholestasis of the neonate.

Phototherapy (PT) has been reported to increase bile acid excretion in the bile of adults with liver cirrhosis. We investigated the effect of PT on the levels of serum total bile acids (STBA), conjugated cholic acid (CCA), conjugated chenodeoxycholic acid (CCDCA), conjugated lithocholic acid (CLCA), and sulfolithocholylglycine (SLCG) in 13 neonates with unconjugated nonhemolytic hyperbilirubinemia before and after 12 h of PT. The treatment produced a statistically significant (p less than 0.02) reduction in both STBA and CCA levels, whereas no effect on the other fractions was observed. The percentage of reduction was the same for STBA and CCA concentrations, indicating that the effect is related to a specific reduction in CCA levels. The magnitude of the expected decrease in the level of serum bilirubin is not correlated with that in bile acids in individual cases. The data are interpreted as suggesting that PT can affect the metabolism of bile acids by decreasing STBA and CCA levels in neonates through an increase in their biliary excretion associated with the reduced intestinal absorption of CCA occurring in newborns.

Bile Acids and Salts↗
PubMedDate not supplied

Repeated rescue of a Broviac catheter: fixation of exposed cuff by a skin flap.

A cutaneous infection exposed the cuff of a Broviac catheter employed for home-TPN in a 3-month-old child with ultra-short bowel syndrome. In order to avoid removal of the catheter, sepsis was abated by antibiotic administration through its lumen, then the exposed cuff was covered and fixed by a skin flap. The advantages proceeding from this sort of "emergency rescue" of the Broviac catheter have been: (1) to avoid a new cutdown in a child already submitted to several attempts of cannulation with sacrifice of major vessels; (2) to resume home total parenteral nutrition (TPN) in a short time, being the patient strictly dependent upon his parenteral intake and to spare a well-functioning catheter. Ten months after the last cuff covering by skin flap, the catheter is safely fixed in place and currently employed for home TPN.

Anti-Bacterial Agents↗
PubMedDate not supplied

[The problem of caustic poisoning in children].

The exposure to caustic substances in childhood, being accidental in most cases, can cause doubts in the initial diagnostic therapeutic approach; the risk of missing lesions following caustic ingestion when symptoms are scarce or lacking is high. The paper provides an overview of the physiopathology and clinical presentation of caustic injuries and stress the possibility of burns of esophagus and/or stomach even without oropharyngeal symptoms and/or signs. The esophagogastroduodenoscopy has now an essential role in the evaluation of gastrointestinal tract injury, as a guide to the therapy and as a prognostic criterion. So it is possible to reduce the risk of poor outcomes by the appropriate treatment. Anyway the primary prevention against the exposition to caustic substances at home is fundamental and must be effected both through active and passive measures.

Adolescent↗
PubMedDate not supplied

[Hypertrophic stenosis of the pylorus. Correlations with allergy to milk proteins and atopy].

We performed a study concerning the relationship between hypertrophic pyloric stenosis (HPS), atopy and cow's milk protein allergy (CMPA). Familial history of atopy was documented in 17 (44.7%) of 38 infants having undergone Ramstedt pyloromyotomy for HPS, in 12 (23%) of 52 infants having undergone surgery for inguinal hernia and in 53 (26.9%) of 290 normal controls (significant differences between HPS and other groups). Moreover 9 (23.6%) of 38 infants with HPS presented personal history of eczema at follow-up compared with 3 (5.7%) infants having undergone surgery for inguinal hernia (p less than 0.01). A significant difference between HPS and other groups was also found when looking for familial history of CMPA: 26.3% vs % and 2.5% respectively (p less than 0.001). Eventually we discovered a higher than expected incidence of CMPA both in a retrospectively evaluated group of HPS and in 24 infants undergone Ramstedt pyloromyotomy and followed according to a standardized protocol for a mean period of 4 months (16.6%). The etiology of HPS remains obscure. Our data however suggest some relationship between HPS, atopy and particularly CMPA.

Female↗
PubMedDate not supplied

Infantile hypertrophic pyloric stenosis and cow's milk intolerance.

Two cases of infantile hypertrophic pyloric stenosis in infants who were exclusively breastfed are reported. In both cases dietetic management succeeded in avoiding surgery. In one case human milk was substituted with casein hydrolysate formula, while in the other cow's milk was excluded from the diet of the mother. A possible casual relationship between cow's milk intolerance and infantile hypertrophic pyloric stenosis is discussed.

Animals↗