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Biomedical subjects

L Ricciardi

Publications and source records attributed to L Ricciardi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Ethylene oxide allergy in dialysis patients.

DESIGN OF STUDY: Two groups of patients undergoing long-term dialysis were studied in order to evaluate the importance of ethylene oxide (EtO) in causing allergic reactions during dialysis. The first group of 50 subjects had never shown any hypersensitivity reactions related to dialysis, whereas the second group of 20 subjects had previously complained of reactions. All the patients underwent a prick test with a standard kit of aeroallergens in order to assess the presence of atopy (in doubtful cases a RAST test was carried out with the same aeroallergens). A blood sample for the investigation of EtO specific IgE antibodies was taken from all the patients; the immunoenzymatic method was used. RESULTS: Sensitivity to EtO is significantly higher in the group of patients with previous allergic reactions during dialysis (55 vs 6% in the control group).

Adult↗
PubMed1997

[Use of ropivacaine in axillary brachial plexus block].

The aim of the study was to evaluate the efficiency and safety of ropivacaine, in comparison with bupivacaine, in axillary brachial plexus block. 24 patients, undergoing upper limb surgery, was divided into 2 homogeneous groups and the local anaesthetics was administered: A (ropivacaine 0.75%, 25 ml; total dose 187.5 mg) and B (bupivacaine 0.5%, 25 ml; total dose 125 mg). The axillary plexus block was executed with the help of an electrostimulator. The results show that using ropivacaine the onset-time is lower and the duration of sensory and motor block is higher than using bupivacaine. In conclusion we can affirm that ropivacaine is a new step in local anaesthetic field.

Adult↗
PubMed1997

[Use of mivacurium in orthopedic surgery: comparison of 2 different-dose inductions].

The aim of our study was to evaluate the efficiency and safety of mivacurium, comparing two dose-induction in patients undergone a minor orthopaedic surgery. 30 patients were divided into two groups and mivacurium were administered at the dose of 0.15 mg Kg-1 and 0.20 mg Kg-1 respectively. The results confirmed its efficiency in short surgery. Mioresolution was excellent only in the second group (0.20 mg Kg-1) despite an histamine-related blood pressure reduction.

Adjuvants, Anesthesia↗
PubMed1994

Effects of acidosis on maximum shortening velocity and force-velocity relation of skinned rat cardiac muscle.

This study was designed to assess whether maximum shortening velocity and force-velocity parameters were reduced by acidosis in rat skinned cardiac trabeculae, as reported for skinned skeletal muscle. Thin trabeculae were dissected from right ventricle of adult male Wistar rats, chemically skinned, and maximally Ca-activated at pH 7.0, 6.6 and 6.2. Maximum tension (Po), maximum shortening velocity evaluated from force-velocity curves (Vmax), and maximum power output (Wmax) were significantly reduced for exposure to pH 6.6 and 6.2. When the value at pH 7.0 is taken as reference, Po decreased by 30% and 49%, Vmax by 17% and 40% and Wmax by 30% and 60% at pH 6.6 and 6.2 respectively. A similar reduction (25% at pH 6.6 and 42% and pH 6.2) was observed when unloaded shortening velocity (Vo) was determined with the slack test method. The results obtained show that both Po and Vmax or Vo are affected by a substantial decrease in pH. The combination between significantly lower Po and Vmax gives rise to significantly lower Wmax. The reduction of maximum shortening velocity (Vmax or Vo) can be explained by assuming either the existence of an internal load or an impairment in actin-myosin interaction.

Acidosis↗
PubMed1993

Mechanical monitoring of fracture healing using ultrasound imaging.

Ultrasound scanning is based on biologic noninvasive use of high-frequency sonic vibration ultrasounds to obtain images of diagnostic relevance in vivo. Ultrasound scanning was used as an additional parameter in evaluation of healing of long bone fractures in patients treated by external fixation devices. Ultrasound image morphology is directly correlated to consolidation of fracture site and displays characteristic cuspid-like shapes in relationship to callus remodeling in response to axial forces. The intensity of reflected echo and the visualization of the longitudinal artifacts structure are significantly related to the calcification process of the periosteal apposition in relationship to healing time. Strain-recorded maximal values variations are synchronous with the variations of reflected echo demonstrating a correlation between the ultrasound image and mechanical status of external callus. In the current state-of-the-art, no quantitative evaluation of mechanical status of fracture site is possible by ultrasound technique alone.

Bony Callus↗
PubMed1992

CD5+ B lymphocytes and T-cell subsets in a case of juvenile rheumatoid arthritis.

Recent research has demonstrated that CD5+ B lymphocytes have an important role in autoimmune and rheumatic diseases. In a case of juvenile rheumatoid arthritis (JRA), we observed the behavior of these cells and other subpopulations of T lymphocytes of peripheral blood before and after therapy with thymopentin (TP5). All the lymphocyte subpopulations returned to normal range, except the CD5+ B cells, where the percentage remained abnormally high (60%). These data suggest that CD5+ B cells can be a useful monitoring index and confirm their important role in the pathogenesis of juvenile rheumatoid arthritis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1992

External callus development on ultrasound and its mechanical correlation.

The authors compare the variations in the ultrasonographic and radiographic images with the strain gage values in long bone fractures treated by external fixation. The three test parameters were applied during the entire healing process of 239 fractures. There is a direct correlation between ultrasonographic changes and the calcification of the periosteal callus; there is also a correlation between the morphologic development visible on ultrasound and the stage of the callus. The strain gage values recorded were consistent with these variations.

Biomechanical Phenomena↗
PubMed1990

Night sweats in Hodgkin's disease. A manifestation of preceding minor febrile pulses.

The authors verified the hypothesis regarding an unawareness of possible febrile alterations during night sleep in patients with Hodgkin's disease who complain of night sweats as their only symptom. In these patients, body temperature was monitored by means of a 0.01 degrees C-sensitive linear transducer coupled with a digital multimeter. The palm of the hand (after it was passively closed in a fist by a full bandage) was the body site where temperature measurement was found to be most comfortable for a sleeping patient and independent of movements during sleep. A good correlation was found between the hand temperature taken with this technique and oral temperature. Of six patients with sweating as their only symptom, sweating recurred during the night in four and during the afternoon in the other two. In all patients sweating was preceded by a critical 0.5 to 1.5 degrees C increase in hand temperature, which took place no more than 30 minutes before sweating. Those with nocturnal sweats awakened during the subsequent sweating-related, rapid temperature decrease. These results are consistent with the occurrence of slight unperceived febrile pulses that precede sweating. The only peculiarity of night sweats consists in the higher probability that a preceding slight temperature rise may not be perceived by a sleeping patient, who is more likely to be awakened by the discomfort of the subsequent sweating. This would also explain the small prognostic significance of these sweats, which is the same as that of the preceding fever. These results are discussed in light of the increasing clinical evidence that patients with Hodgkin's disease are often affected by an instability of the thermoregulatory hypothalamic centers.

Adolescent↗
PubMed1990

Evidence for an intrinsic mechanism regulating heart rate variability in the transplanted and the intact heart during submaximal dynamic exercise?

STUDY OBJECTIVE: The aim was to assess the changes in sympatho-vagal balance which occur with exercise. DESIGN: The power spectrum of RR interval fluctuations (low frequency [LF] and high frequency components [HF]) was determined before, during, and after graded work load exercise on a cycle ergometer. The power spectrum of the respiratory signal, oxygen consumption, and respiratory volumes were also evaluated. In all subjects HF was considered to be an index of respiratory sinus arrhythmia. In normal subjects HF and LF were considered to be indices of relative vagal and sympathetic activity, respectively, whereas in heart transplant subjects HF was considered as a respiratory modulation of the intrinsic heart rate, and not dependent on autonomic tone. Heart rate variability was evaluated as RR interval variance. SUBJECTS: 15 normal subjects (six trained cyclists and nine healthy sedentary subjects) and six orthotopic heart transplant recipients took part in the study. MEASUREMENTS AND MAIN RESULTS: During the first part of exercise, heart rate increased, RR interval variance decreased, HF decreased, and the relative amount of LF increased both in sedentary and athletic subjects, suggesting a relative increase in sympathetic tone. However, when approaching peak exercise, while heart rate further increased and the variance slightly decreased, the relative proportion of LF decreased and HF proportionally increased. At peak exercise HF accounted for 99.9% of heart rate variability in athletic subjects and for 88.9% in sedentary subjects (p less than 0.001 v baseline and v LF in both groups). In heart transplant subjects both the variance and the HF increased from the beginning of exercise (p less than 0.05), and showed a direct correlation with ventilatory variables and an inverse correlation with heart rate (r = 0.794, p less than 0.001, multiple regression analysis). No measurable LF components could be obtained in these subjects. During recovery, while the heart rate decreased and the RR interval variance increased, there was a relative increase in LF and a relative decrease in HF in normal subjects (either sedentary or athletic). Similarly, in heart transplant subjects, there was a decrease in HF during recovery. Thus the increase in HF at peak exercise in normal subjects contrasts with all the other data which suggest a prevalence in sympathetic tone during the entire exercise and the early recovery period, but appears similar to the increase in HF observed in heart transplant subjects due to the effect of increased ventilation during exercise. CONCLUSIONS: These findings suggest that at peak exercise a non-autonomic mechanism, possibly intrinsic to the heart muscle, may determine heart rate fluctuations in synchrony with ventilation in the intact as well as in the denervated human heart.

Adolescent↗
PubMed1987

Relation between ventricular DNA content and number of myocytes and non-myocytes in hearts of normotensive and spontaneously hypertensive rats.

Myocardial DNA concentration and ventricular weight were measured in the hearts of normal and spontaneously hypertensive rats varying in age from 1 day to 1 year and the ventricular DNA content calculated. A linear relation between ventricular DNA content and ventricular weight was observed in both rat strains. This linear relation was deduced theoretically, assuming that the number of ventricular non-myocytes per heart was proportional to ventricular weight and that the number of ventricular myocytes per heart was constant after the first postnatal week. The fit with experimental data produced values of the number of ventricular myocytes (42.5 X 10(6] and non-myocytes (199 X 10(6) per gram of ventricular tissue) in normal rat heart. Using published data on ventricular volume occupied by myocytes (80%) and myocardial specific density (1.06 g X ml-1), the mean(SD) volume of individual myocytes could be calculated (17758(2632) multiplied by ventricular weight, expressed in micron 3 X g). The values obtained compared well with experimental observations reported in the present study (18504(131) micron 3 X g) and in other studies. Hearts from spontaneously hypertensive rats had lower numbers of myocytes (37.4 X 10(6] and non-myocytes (180 X 10(6) per gram) per heart than normal hearts with identical ventricular weights. Hearts of normal 2 month old rats that were made hypertrophic by various means were identical to non-hypertrophic hearts of normal older rats with identical ventricular weights in relation to the number of ventricular myocytes and non-myocytes per heart. It is concluded that ventricular hypertrophy induced in young adult rats might be regarded as normal growth occurring at an accelerated rate.

Animals↗
PubMed1987

Uncemented hip prosthesis: a new screw stem model with a review of 73 cases.

A new uncemented prosthetic stem based on a screw system is presented. The biomechanical, metallurgic and technical principles on which this innovation is based are discussed. The indication and surgical technique are described and 73 cases are reported. The new stem is easy to apply and makes it possible to regulate anteversion precisely, and above all, to satisfy the preconceived biomechanical requirements. Some cases with a shorter follow-up are included because we allowed a suitable time lapse after our earlier cases before extending our indication. However, there is considerable documentation of screw stems in the literature on the long term toleration of screw stems.

Adult↗
PubMed1986

Effects of acidosis on force-sarcomere length and force-velocity relations of rat cardiac muscle.

The effect of hypercapnic acidosis was compared with that of lowering extracellular calcium concentration ([Ca++]o) in rat cardiac trabeculae. The relations between force and sarcomere length and between force and velocity were studied. Sarcomere length was measured by means of laser diffraction techniques and sarcomere shortening velocity by means of isovelocity releases. The curve representing the relation between force and sarcomere length shifted from convex towards the ordinate (pH 7.35) to convex towards the abscissa (pH 6.68) as after [Ca++]o had been reduced from 1.5 to 0.3 mmol X litre-1. Increasing [Ca++]o at low pH from 1.5 to 4.0 mmol X litre-1 allowed the shape of the relation to be restored, but force values failed to return to control values. The relation between force and pH over the range 6.22-7.94 was also tested. During steady low pH maximum unloaded sarcomere shortening velocity was not significantly different from control values whereas it was decreased at low [Ca++]o. Under both conditions maximum isometric tension (Po) was reduced. The results are consistent with the hypothesis that H+ ions cause a shift of the force-p Ca curve to the right at all sarcomere lengths, as a result of competition between Ca++ and H+ ions for binding to the myofilaments.

Acidosis, Respiratory↗