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Biomedical subjects

G Conti

Publications and source records attributed to G Conti.

At least 19 recordsLinked to original sources

Severe form of Freeman-Sheldon syndrome associated with brain anomalies and hearing loss.

We describe a child with whistling face and multiple contractures, including ulnar deviation of fingers, compatible with a diagnosis of Freeman-Sheldon syndrome (FSS). This patient also presented severe hypertonicity, multiple episodes of pneumonia, difficulty in swallowing, and poor weight gain, which are characteristic of the most severe cases of FSS. A brain CT scan showed cerebellar and brainstem atrophy. Auditory brainstem responses were absent. The child died at 5 months of respiratory failure. This case suggests the possibility that, especially in the most severe forms, brain abnormalities may be responsible for some of the clinical manifestations of this syndrome, i.e., respiratory problems, difficulty in swallowing and severe hypertonicity. We assume that there is more than one pathogenetic mechanism (muscular, skeletal, and neurological) underlying FSS, which, together with the genetic heterogeneity and the wide range of clinical symptoms leads us to suggest that it is more appropriate to speak of a Freeman-Sheldon spectrum rather than syndrome and that thorough investigation for CNS and auditory abnormalities should be part of the initial work-up of these patients.

Adult

Early and late onset bacteremia have different risk factors in trauma patients.

OBJECTIVE: The aim of this study was to identify risk factors and to describe epidemiological patterns for early-(EOB) and late-onset bacteremias (LOB) after trauma. DESIGN: A prospective study conducted on 141 consecutive trauma patients. SETTING: A general intensive care unit (ICU) of a university hospital. PATIENTS: All multiple trauma patients admitted to our general intensive care unit (ICU) from December 1990 to May 1992 were prospectively enrolled in the study. The following information was collected for each patient and recorded in a computer database: demography, severity of trauma according to the Abbreviated Injury Scale (AIS), severity of coma according to the Glasgow Coma Scale (GCS), presence of pneumothorax, pulmonary contusion, rib fractures, hemothorax, and abdominal trauma, use of mechanical ventilation, and placement of central venous catheters. Bacteremias were defined as EOB when onset occurred within 96 h after trauma, and as LOB when appearing after 96 h from trauma. RESULTS: Thirty-seven patients developed bacteremia during their ICU stay (26%): 11 (29.7%) EOB and 26 (70.3%) LOB. Gram-positive cocci were isolated more frequently in EOB than in LOB (chi 2 = 4.1, P = 0.04). The risk of EOB was significantly increased by the presence of pulmonary contusion [relative risk (RR) 15.0; confidence interval (CI) 1.99-113.25], pneumonia before the onset of bacteremia (RR 3.56; CI 1.17-10.69), AIS score greater than 32 and an abdominal injury score greater than 9 (RR 3.11; CI 1.02-9.49), while intravascular catheters and mechanical ventilation did not represent risk factors for EOB. LOB had a very different pattern and their risk was significantly increased by exposure to intravascular catheters (RR 4.96; CI 1.23-19.94) and to mechanical ventilation lasting more than 7 days (RR 3.6; CI 1.6-8.1). CONCLUSIONS: Scoring with the AIS of the abdominal and thoracic trauma at admission to the ICU appears a useful tool for identifying trauma patients at increased risk of EOB. A rigorous policy of catheter placement and maintenance as a means of reducing late bacteremias in trauma patients is essential.

Abdominal Injuries

Induction of p75NGFR in human diabetic neuropathy.

In this immunohistochemical study we investigated the expression of low-affinity NGF receptor (p75NGFR) in peripheral nerves from 16 patients with type I or type II diabetes mellitus. Fourteen nerves from age- and sex-matched normal individuals and nine nerves from non-diabetic patients with ischemic neuropathy served as controls. All nerve samples were preliminarily examined by standard histology, fiber teasing and electron microscopy. Increased p75NGFR immunoreactivity was detectable within the endoneurium of cross-sections from ischemic and particularly from diabetic nerves. Immuno-teasing demonstrated that p75NGFR immunostaining was distributed along the entire length of isolated nerve fibers undergoing axonal degeneration. Quantitative assessment of p75NGFR immunoreactivity, performed by histospectrophotometry and expressed as percentage of adsorbance, was 21.20 +/- 3.50 in nerves from diabetic patients, 13.35 +/- 3.62 in nerves from non-diabetic patients with ischemic neuropathy and 9.02 +/- 2.75 in normal controls. The increased expression of p75NGFR in diabetic nerves is consistent with an axonopathic defect and further suggests involvement of NGF and other neurotrophins in the pathogenesis of human diabetic neuropathy.

Adult

O2 consumption-O2 delivery relationship and arteriolar resistance in the forearm of critically ill patients measured by near infrared spectroscopy.

Eight patients with severe sepsis, four with septic shock, and eight without sepsis were studied to investigate whether skeletal muscle influences the whole body O2 consumption (VO2)-O2 delivery relationship and hemodynamics. A forearm VO2-O2 delivery dependency was observed only in nonseptic patients, in whom no whole body VO2-O2 delivery dependency appeared. No forearm VO2-O2 delivery relationship was observed in septic and shock patients, in whom whole body VO2-O2 delivery dependency was found. In shock patients the lack of forearm VO2-O2 delivery dependency was associated with low forearm arteriolar resistance (FAR) even at a relatively low forearm blood flow (FBF). Neither a relationship between forearm VO2 and whole body VO2 nor between FAR and SVR was found in any groups of patients. Septic shock was associated with low FAR that was not affected by the FBF decrease, indicating that in this condition, hemodynamics could be influenced by skeletal muscle resistance.

Aged

Effects of assisted ventilation on the work of breathing: volume-controlled versus pressure-controlled ventilation.

During assisted ventilation, the same tidal volume can be delivered in different ways, with the possibility for the physician to vary the ventilatory target (pressure or volume) and the peak flow setting. We compared the effects on the respiratory work rate of assisted ventilation, delivered either with a square wave flow pattern (assist control ventilation [ACV]) or with a decelerating flow pattern and a constant pressure (assisted pressure-control ventilation [APCV]). In the first part of the study where seven patients were studied, inspiratory time and tidal volume were similar in the two modes of ventilation. High and moderate levels of tidal volume (VT) were studied (12 ml/kg and 8 ml/kg, respectively). To obtain moderate VT, inspiratory time was kept constant and, therefore, mean inspiratory flow was reduced. At high VT, no difference between ACV and APCV was noted for breathing pattern, respiratory drive indexes, respiratory muscle work, or arterial blood gases. All patients exhibited respiratory alkalosis. At moderate VT, normal pH was achieved. In this situation significantly lower levels were observed during APCV than during ACV for the power of breathing (10 +/- 2 versus 19 +/- 5 J/min, p<0.05), transdiaphragmatic pressure swing (7 +/- 1 versus 11 +/- 2 cm H2O, p<0.05), and pressure-time index (252 +/- 43 versus 484 +/- 114 cm H2O.s, p<0.05), even though breathing pattern and gas exchange were similar. In the second part of the study where six additional patients were studied, tidal volume was kept constant at a moderate level (8 ml/kg), and we studied the effect of shortening inspiratory time and increasing mean inspiratory flow. At moderate VT and high inspiratory flow, no significant differences could be found between ACV and APCV, and although pressure-time index tended to be lower during APCV, absolute levels of effort were of small magnitude (56 +/- 55 versus 76 +/- 55 cm H2O.s). We conclude that at moderate VT and low flow rates only, inspiratory assistance delivered at a constant pressure reduces the respiratory work rate more effectively than assist control ventilation.

Aged

Estimation of occlusion pressure during assisted ventilation in patients with intrinsic PEEP.

We conducted a study to assess the validity of the occlusion pressure (P0.1) measured during activation of the trigger mechanism (P0.1(aw)trig) in patients showing variable levels of PEEPi during pressure-support ventilation. We first compared P0.1(aw)trig and P0.1 measured with the conventional method (i.e., the airway pressure drop after the first 100 ms of an occluded inspiration) in 16 patients with chronic obstructive pulmonary disease (COPD). We observed good agreement and a highly significant correlation (r = 0.99; bias = 0.3 +/- 0.5 cm H20) between the two methods. In a second part of the study, we compared, in 17 patients, P0.1(aw)trig with (P0.1(es)), measured as the depression generated on the esophageal pressure tracing in the first 100 ms of the inspiratory negative swing, and with P0.1 measured on the P(es) tracing simultaneously with P(aw)trig (P0.1(es-synchro)). Our results showed a good correlation and good agreement between P(aw)trig and P0.1(es) (r = 0.92; bias = 0.3 +/- 0.5 cm H20); P(aw)trig and P0.1(es-synchro) (r = 0.97; bias = 0.1 +/- 0.2 cm H20); and P0.1(es) and P0.1(es-synchro) (r = 0.95, bias = 0.2 +/- 0.4 cm H20), respectively. This study suggests that reliable measurements of inspiratory drive can be obtained easily, on a breath-by-breath basis, from airway pressure tracings during pressure-support ventilation in patients with variable levels of PEEPi.

Airway Resistance

Noninvasive positive-pressure ventilation via face mask during bronchoscopy with BAL in high-risk hypoxemic patients.

STUDY OBJECTIVE: The aim of this study was to assess the feasibility and safety of noninvasive positive-pressure ventilation (NPPV) via a face mask to aid in performing fiberoptic bronchoscopy (FOB) with BAL in immunosuppressed patients with gas exchange abnormalities that contraindicate using conventional unassisted FOB. STUDY POPULATION: Eight consecutive immunosuppressed patients (40 +/- 14 years old) with suspected pneumonia entered the study. Entrance criteria included the following: (1) PaO2/fraction of inspired oxygen (FIo2) of 100 or less; pH of 7.35 or more; and (3) improvement in O2 saturation during NPPV before initiating FOB. INTERVENTION: Patients had routine application of topical anesthesia to the nasopharynx. A full face mask was connected to a ventilator (Servo 900C; Solna, Sweden) set to deliver continuous positive airway pressure (CPAP) of 4 cm H2O, pressure support ventilation of 17 cm H2O, and 1.0 FIo2. The mask was secured to the patient with head straps. NPPV began 10 min before starting FOB and continued for 90 min or more after the procedure was completed. The bronchoscope was passed through a T-adapter and advanced through the nose. BAL was obtained by sequential instillation and aspiration of 5 to 25 mL aliquots of sterile saline solution through a bronchoscope wedged in a radiographically involved subsegment. Oxygen saturation, heart rate, respiratory rate, and arterial blood gases were monitored during the study. RESULTS: NPPV significantly improved PaO2/FIo2 and O2 saturation. FOB with NPPV was well tolerated, and no patient required endotracheal intubation. A causative pathogen was identified by BAL in all patients. Six patients responded to treatment and survived hospital admission. Two patients died 5 to 7 days after FOB from unrelated complications of the underlying illness. CONCLUSIONS: NPPV should be considered during bronchoscopy of immunosuppressed patients with severe hypoxemia.

Adult

[Role of BCG in T1G3 bladder transitional cell carcinoma (TCC): our experience].

High grade superficial TCC of the bladder (T1 G3) has an important risk of recurrence and/or progression (40%) after TUR-B and a low survival rate (57% at 3 years, 50% at 10 years). Intravescical treatment with BCG seems to be able to reduce these rates. 64 patients with T1 G3 vescical TCC underwent a "second look" TUR-B. 9/64 patients presented locally advanced tumor (T2-3) or persistent high risk superficial TCC (T1 G3 + Tis) and underwent to early cistectomy. BCG intravescical therapy has been performed in the remaining 55 patients: 10 of them had not been evaluated because local or sistemic toxicity and consequent early interruption of treatment. BCG Pasteur was given weekly at the dose of 75 mg for two cycles of 6 weeks with a rest period of 6 weeks between the two cycles and then monthly for one year and every three months during next two years too. After the first 6 weeks 43/45 patients resulted tumor-free and 2/45 presented persistent Tis: after the second 6 weeks-cycle of BCG, two other patients had evidence of vescical TCC (one T2 G3 and the other T1 G3); all these four patients were submitted to radical cystectomy or radiotherapy. Of the reamining 41 patients, 28 presented had no recurrences, nowadays living and tumor-free; 3 presented local neoplastic progression and dead; relapsed in T1 G2 and are living NED after local chemotherapy. At a mean follow-up of 18 months, the total amount of recurrences is 17/45 (38%), progression rate is 4/45 (8.8%), exitus 5/45 (11%) and living NED are 28/45 (62%). In our opinion local BCG treatment for T1 G3 bladder cancer, after TUR--B, seems to be able to reduce the risk of recurrence and mortality.

Administration, Intravesical

Radio immune Western blotting: a possible solution to indeterminate conventional Western blotting results for the serodiagnosis of HIV infections.

Western blot is used worldwide as a confirmatory assay after a positive or doubtful ELISA result in the serodiagnosis of HIV infections. Despite the use of this test some results may be not definitive due to the presence in Western blot of only few or a single band to HIV protein. This result has been defined as indeterminate. To resolve indeterminate results obtained with conventional Western blotting (WB) we used radio immune Western blotting (RIWB), a method capable of detecting antibodies to HIV-1 proteins with greatly increased sensitivity with respect to conventional WB. We used RIWB to perform a retrospective survey on 20 sera belonging to individuals undergoing HIV serodiagnosis (not blood donors) with positive or borderline EIA results, and indeterminate WB results who only later fully seroconverted. Fifteen of the sera tested by RIWB showed a positive result which clarified any doubtful indeterminate WB result; all bands present in conventional WB were enhanced in intensity using RIWB and new bands, absent in the WB assay, were highlighted using RIWB. RIWB may resolve most indeterminate WB results.

AIDS Serodiagnosis

Effects of three techniques of lung management on pulmonary function during cardiopulmonary bypass.

In this study, 30 patients undergoing elective myocardial revascularization were divided randomly in three groups (10 patients each) with different management of the lungs during CPB: Group 1, lungs deflated; Group 2, static inflation with PEEP = 5 cmH2O and FIO2 = 1.0; Group 3, static inflation with PEEP = 5 cmH2O and FIO2 = 0.21. Measurements (Qs/Qt, P(A-a)O2, PaO2, Cstat, Cdyn, PIP, AUTO-PEEP, Rrs,max, Rrs,min and DRrs) were performed after the induction of anesthesia (T0), 20 minutes (T1) and 2 hours (T2) after the end of CPB. Respiratory mechanics data were obtained only at T0 and T2 because the sternal retraction. The Group 1 presented a statistically significant increase in Qs/Qt, P(A-a)O2 and Peak Inspiratory Pressure (PIP); in this group we noticed also a decrease in PaO2 values, static compliance (Cstat) and dynamic compliance (Cdyn) values comparing basal versus T1 and T2 values. The Group 2 showed a statistically significant increase in Qs/Qt and P(A-a)O2 values; also in this group we observed a statistically significant decrease in PaO2 and Cdyn values comparing basal versus T1 and T2 values. The Group 3 presented a statistically significant decrease in PaO2 values (basal versus T1 and T2); this group also presented an increase in Qs/Qt values, in the immediate postbypass period (T1), and P(A-a)O2 values significantly increase comparing basal versus T1 and T2 values. In all the three groups the respiratory system resistance and AUTO-PEEP values were unchanged after the end of CPB. The comparison between the groups showed a significant minor impairment of gas exchange (PaO2 and P(A-a)O2), Qs/Qt and Cstat in the third group of patients. These results show that lungs inflation with air during CPB, effectively preserve respiratory system mechanics: this might be due to a preservation of bronchial perfusion simply due to the mechanic expansion of the lung otherwise compromized when the lungs are completely collapsed. However it is necessary to emphasize that CPB has negative effects on gas-exchange whatever technique of lung management is used.

Anesthesia, Inhalation

DNA interaction and electrochemical properties of bis-1-aminomethylnaphthalenes and related compounds. A correlation with their antineoplastic activity.

Bis-1-aminomethylnaphthalenes constitute a new type of molecule with antineoplastic activity. As a first approach to determine the action mechanism, the interaction degree of these compounds and some less active analogous, with calf thymus DNA, by UV spectrophotometry, and the redox performance by cyclic voltammetry was correlated with their activity on neoplastic cell lines. It suggests that the most active members interact closely with DNA but do not show any redox process at biological potentials.

Antineoplastic Agents

Low-affinity nerve growth factor receptor expression in sciatic nerve during P2-peptide induced experimental allergic neuritis.

Northern blot, immunocytochemistry, and single nerve fiber immunostaining were used to determine the expression of low-affinity nerve growth factor (NGF) receptor (p75NGFR) in the peripheral nervous system of Lewis rats during the course of experimental allergic neuritis (EAN) induced with 100 micrograms of 'SP26' synthetic peptide, corresponding to residues 53-78 of bovine P2 myelin protein. This severe reversible polyneuropathy, characterized by extensive multifocal demyelination in nerve roots, and axonal degeneration within sciatic nerve, represents a useful tool to investigate Schwann cell gene expression in these different pathological conditions. Our results showed that both p75NGFR mRNA and protein were induced within sciatic nerve by day 18 and 23 after 'SP26' immunization. By this time, however, p75NGFR was not detectable in roots of cauda equina. These data demonstrate that, during EAN induced by immunization with 100 micrograms of 'SP26', p75NGFR is up-regulated in Schwann cells and in nerve fibers distally along the nerve. This suggests that the induction of the receptor in sciatic nerve during P2-peptide EAN is related to the loss of axonal contact by Schwann cells.

Animals

Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease.

BACKGROUND: In patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation may be used in an attempt to avoid endotracheal intubation and complications associated with mechanical ventilation. METHODS: We conducted a prospective, randomized study comparing noninvasive pressure-support ventilation delivered through a face mask with standard treatment in patients admitted to five intensive care units over a 15-month period. RESULTS: A total of 85 patients were recruited from a larger group of 275 patients with chronic obstructive pulmonary disease admitted to the intensive care units in the same period. A total of 42 were randomly assigned to standard therapy and 43 to noninvasive ventilation. The two groups had similar clinical characteristics on admission to the hospital. The use of noninvasive ventilation significantly reduced the need for endotracheal intubation (which was dictated by objective criteria): 11 of 43 patients (26 percent) in the noninvasive-ventilation group were intubated, as compared with 31 of 42 (74 percent) in the standard-treatment group (P < 0.001). In addition, the frequency of complications was significantly lower in the noninvasive-ventilation group (16 percent vs. 48 percent, P = 0.001), and the mean (+/- SD) hospital stay was significantly shorter for patients receiving noninvasive ventilation (23 +/- 17 days vs. 35 +/- 33 days, P = 0.005). The in-hospital mortality rate was also significantly reduced with noninvasive ventilation (4 of 43 patients, or 9 percent, in the noninvasive-ventilation group died in the hospital, as compared with 12 of 42, or 29 percent, in the standard-treatment group; P = 0.02). CONCLUSIONS: In selected patients with acute exacerbations of chronic obstructive pulmonary disease, noninvasive ventilation can reduce the need for endotracheal intubation, the length of the hospital stay, and the in-hospital mortality rate.

Acute Disease

Proximal femoral focal deficiency (PFFD) and fibular A/hypoplasia (FA/H): a model of a developmental field defect.

Proximal femoral focal deficiency (PFFD) and fibular a/hypoplasia (FAH) are distinct malformations of the lower limbs. Both can occur as isolated defects or in association with other limb malformations. In fact, fibular defects frequently are present in PFFD, and, conversely, femoral abnormalities can be found in the presence of a typical FAH picture. We report on 5 patients with a variable combination of femoral and fibular defects. In one of them unilateral PFFD was associated with lateral foot defects, in the absence of fibular abnormalities, and with a phenotype similar to that observed in the femoral hypoplasia/unusual face syndrome (FH/UFS). Another patient had isolated PFFD on one side, with controlateral absence of femur, fibula, and tibia. Another patient had a PFFD, fibular hypoplasia, and abnormalities of fibular foot rays, and the last 2 patients, a father and son, had, respectively, bilateral foot malformations plus fibular and tibial hypoplasia in the father and a PFFD in the son. These observations represent a further demonstration of the existence of a fibular developmental field, and contribute to the definition of its spatial boundaries. The variable involvement of elements comprised in the developmental field can be explained by multifactorial etiology.

Abnormalities, Multiple

Paralysis has no effect on chest wall and respiratory system mechanics of mechanically ventilated, sedated patients.

OBJECTIVE: To evaluate the separate effects of sedation and paralysis on chest wall and respiratory system mechanics of mechanically ventilated, critically ill patients. SETTING: ICU of the University "La Sapienza" Hospital, Rome. PATIENTS AND PARTICIPANTS: 13 critically ill patients were enrolled in this study. All were affected by disease involving both lungs and chest wall mechanics (ARDS in 4 patients, closed chest trauma without flail chest in 4 patients, cardiogenic pulmonary oedema with fluidic overload in 5 patients). MEASUREMENTS AND RESULTS: Respiratory system and chest wall mechanics were evaluated during constant flow controlled mechanical ventilation in basal conditions (i.e. with the patients under apnoic sedation) and after paralysis with pancuronium bromide. In details, we simultaneously recorded airflow, tracheal pressure, esophageal pressure and tidal volume; with the end-inspiratory and end-expiratory airway occlusion technique we could evaluate respiratory system and chest wall elastance and resistances. Lung mechanics was evaluated by subtracting chest wall from respiratory system data. All data obtained in basal conditions (with the patients sedated with thiopental or propofol) and after muscle paralysis were compared using the Student's t test for paired data. The administration of pancuronium bromide to sedated patients induced a complete muscle paralysis without producing significant modification both to the viscoelastic and to the resistive parameters of chest wall and respiratory system. CONCLUSIONS: This study demonstrates the lack of additive effects of muscle paralysis in mechanically ventilated, sedated patients. Also in view of the possible side effects of muscle paralysis, our results question the usefulness of generalized administration of neuromuscular blocking drugs in mechanically ventilated patients.

Adult

Comparative evaluation of the haemodynamic effects of continuous negative external pressure (CNEP) and positive end-expiratory pressure (PEEP) in mechanically ventilated trauma patients.

OBJECTIVE: To compare the haemodynamic effects of identical values of continuous negative external pressure (CNEP) and positive end-expiratory pressure (PEEP) in a group of mechanically ventilated patients. SETTING: General ICU, Vicenza Hospital, Italy. PATIENTS: 15 consecutive patients, admitted after road accident trauma. METHODS: We compared the haemodynamic effects of ZEEP, 10 cmH2O of PEEP, and 10 cmH2O CNEP, applied in random order, in 15 head trauma patients under going controlled mechanical ventilation; 9 had associated thoracic trauma, while 6 did not have lung involvement. CNEP was obtained with a "poncho". RESULTS: We observed a significant increase in CI during CNEP, compared with both ZEEP and PEEP 10 cmH2O. Accordingly the oxygen delivery index significantly increased during CNEP, compared with PEEP 10 cmH2O. Conversely, Qs/Qt decreased with CNEP, if compared with PEEP, both in patients with and without lung damage. CONCLUSION: CNEP can significantly increase CI in mechanically ventilated patients in patients with and without associated lung damage.

Blood Gas Analysis

Origin and distribution of P13 and P14 far-field potentials after median nerve stimulation. Scalp, nasopharyngeal and neck recording in healthy subjects and in patients with cervical and cervico-medullary lesions.

We studied median nerve SEPs in 10 healthy subjects, by means of simultaneous recording over the scalp, around the neck and near the ventral surface of the medulla using a nasopharyngeal (NP) electrode. This recording technique enabled us to clearly differentiate P13 and P14 potentials. The former was always found in NP records, while the latter was more evident in scalp traces. The same technique was used to study 9 patients with various lesions of the cervical cord or cervico-medullary junction. Patients with high cervical lesions demonstrated abnormalities of both P13 and P14 potentials, while patients with lesions of the cervico-medullary junction demonstrated a clear dissociation between normal P13 in scalp and NP traces, and abnormal scalp P14. Patients with lower cervical lesions, selectively involving the central grey matter, showed normal P13 and P14 potentials, in spite of abnormal N13 cervical responses. Our findings strongly suggest that both scalp and NP P13 have the same generators in higher segments of the cervical cord, and that NP more than scalp records are effective in analyzing the P13 response. We suggest that the selective recording of the P13 potential could be useful in the assessment of focal lesions of the higher cervical cord or of the cervico-medullary junction.

Adult