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Biomedical subjects

G Conti

Publications and source records attributed to G Conti.

At least 37 records · Page 2Linked to original sources
PubMed1996

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↗
PubMed1996

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↗
PubMed1996

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1995

Generation of human auditory steady-state responses (SSRs). I: Stimulus rate effects.

Auditory evoked responses were recorded in 16 normally hearing subjects in order to investigate the mechanisms underlying the generation of the 40 Hz steady-state response (SSR). In the first part of our study, auditory potentials were evoked by 0.1 ms clicks presented at 105 dB p.e. SPL with repetition rates of 7.9 (to obtain middle latency response, MLR), 20, 30, 40, 50, 60 Hz. In each subject predictions of the responses recorded at stimulus repetition rates of 30, 40, 50, 60 Hz were synthesized by superimposing MLRs at suitable time intervals. The calculated mean amplitude/rate and phase/rate functions behaved similarly for the recorded and predicted curves, showing the highest amplitude at 40 Hz and a linear increase of phase values when increasing the stimulus rate. Nevertheless the synthetic curves closely predicted amplitude and phase values of the recorded responses only at 40 Hz. At frequencies below 40 Hz, the mean amplitude of the predicted curve was lower than that of the recorded one while at frequencies above 40 Hz the mean amplitude was higher. Predicted phase values were found lagging at 30 Hz, and leading at 50 Hz and 60 Hz in comparison to phase values calculated on the recorded responses. Our findings suggest that a model based on the linear addition of transient MLRs is not able to adequately predict steady-state responses at stimulus rates other than at 40 Hz. Other mechanisms related to the recovery cycle of the activated system come into play in the steady-state response generation causing a decrease in amplitude and an increase in phase lag when increasing the stimulus repetition rate.

Acoustic Stimulation↗
PubMed1995

Generation of human auditory steady-state responses (SSRs). II: Addition of responses to individual stimuli.

In order to investigate the generation of the 40 Hz steady-state response (SSR), auditory potentials evoked by clicks were recorded in 16 healthy subjects in two stimulating conditions. Firstly, repetition rates of 7.9 and 40 Hz were used to obtain individual middle latency responses (MLRs) and 40 Hz-SSRs, respectively. In the second condition, eight click trains were presented at a 40 Hz repetition rate and an inter-train interval of 126 ms. We extracted from the whole train response: (1) the response-segment taking place after the last click of the train (last click response, LCR), (2) a modified LCR (mLCR) obtained by clearing the LCR from the amplitude enhancement due to the overlapping of the responses to the clicks preceding the last within the stimulus train. In comparison to MLRs, the most relevant feature of the evoked activity following the last click of the train (LCRs, mLCRs) was the appearance in the 50-110 ms latency range of one (in 11 subjects) or two (in 2 subjects) additional positive-negative deflections having the same periodicity as that of MLR waves. The grand average (GA) of the 40 Hz-SSRs was compared with three predictions synthesized by superimposing: (1) the GA of MLRs, (2) the GA of LCRs, (3) the GA of mLCRs. Both the MLR and mLCR predictions reproduced the recorded signal in amplitude while the LCR prediction amplitude resulted almost twice that of the 40 Hz-SSR. With regard to the phase, the MLR, LCR and mLCR closely predicted the recorded signal. Our findings confirm the effectiveness of the linear addition mechanism in the generation of the 40 Hz-SSR. However the responses to individual stimuli within the 40 Hz-SSR differ from MLRs because of additional periodic activity. These results suggest that phenomena related to the resonant frequency of the activated system may play a role in the mechanisms which interact to generate the 40 Hz-SSR.

Acoustic Stimulation↗
PubMed1995

Control of post anaesthetic shivering with nefopam hydrochloride in mildly hypothermic patients after neurosurgery.

Postoperative shivering may be prevented by maintaining normothermia intraoperatively or it may be treated using specific drugs. The aim of this study was to compare the efficacy of nefopam hydrochloride (nefopam) to that of clonidine and meperidine in patients undergoing elective neurosurgical procedures. Three groups of patients were included in the study. Patients in group A (60) received i.v., at random, 20 mg of nefopam, 50 mg of meperidine or 150 micrograms of clonidine in the immediate postoperative period. The incidence of shivering and the time at which shivering ceased were noted, along with central temperature and main haemodynamic changes. Group B (20) received i.v., at random, either 10 mg of nefopam or saline before awakening from anaesthesia. The effects of nefopam on central temperature, oxygen consumption (Vo2), carbon dioxide production (VcO2), basal metabolic rate (BMR) and energy expenditure (EE) were investigated. Group C (10) received i.v. 20 mg of nefopam during surgery: cerebrospinal fluid pressure (CSFP), cerebral perfusion pressure (CPP) and electroencephalogram (EEG) were monitored. In group A nefopam stopped shivering in 95% of patients when compared to meperidine and clonidine, which were effective in 32% and 40% of patients respectively. In group B, only 10% of patients receiving nefopam had postoperative shivering, Vo2, VcO2 and EE were significantly lower in patients treated with nefopam than those in the control group. No changes in CSFP, CPP or EEG were observed in group C. In conclusion, nefopam seems to be more effective than clonidine or meperidine in quickly suppressing shivering, without producing significant adverse reactions.

Adult↗
PubMed1995

High IL-6 serum levels are associated with septic shock and mortality in septic patients with severe leukopenia due to hematological malignancies.

The serum levels of immunoreactive interleukin-6 (IL-6) and tumor necrosis factor (TNF) were analyzed in 14 leukopenic patients with documented sepsis, at 60 min (T0), 24 h (T1), and one week (T3) after the onset of sepsis syndrome. Sera from 10 leukopenic patients without sepsis (controls) were also tested. All septic patients had high IL-6 levels at T0. These levels persisted only in the seven patients who died of septic shock, presenting a 30-fold increase (p<0.001) as compared to the survivors and the controls. At T3, 7 survivors had recovered from sepsis and showed low IL-6 serum levels. The TNF serum concentration always <30 pg/ml in both the subjects and in the controls. The C-reactive protein (CRP) and clinical parameters appeared to be less specifically associated with shock and mortality than IL-6.

Adult↗
PubMed1995

[Role of urodynamics in implantation of prostatic stents].

Recent anxieties about the risk of prostate surgery in elderly and unfit patients have generated considerable interest in a number of new permanent prostatic stents. The prostatic Urolume Wallstent was positioned in 34 patients affected by BPH, all with acute or chronic retention of urine, most of whom were unfit for conventional prostatic surgery; the average follow-up is 14 months (range 9-24 months). The stents were inserted with the patients under local or regional anesthesia. 14 patients had prevalent irritative pre-retention symptoms, while in 18 patients obstructive symptoms were dominant; in the remaining 2 patients symptoms were minimal. Cystometry was performed in 29 patients before treatment for evaluation of detrusor activity. Following stent insertion, 31 patients were able to empty satisfactorily, while the remaining 3 patients presented chronic retention because of detrusor failure, evidenced before treatment. Most patients experienced frequency and urgency for several months (90% of 14 patients with pre-treatment irritative symptoms; 25% of the other 20 patients). No incrustation occurred, no serious urosepsis was registered. In 3 patients we need to put in a second stent. In the first weeks, 4 stents were removed for dislocation and then replaced endoscopically without difficulty or damage to the urethra. After 6 months, other 5 stents were definitively removed because of persistent unbearable irritative symptoms with poor quality of life (all these patients had severe pre-operative detrusor overactivity).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

[Wolfram syndrome. Personal experience].

We report on a young patient who suffered from diabetes mellitus and neurosensorial deafness from the age of two. One year later she was noted to have deteriorated vision and the diagnosis of optic atrophy was made, her visual acuity decreased progressively. At the age of six she was admitted to our hospital because of thiamine responsive megaloblastic anemia, a rare clinical feature of Wolfram's syndrome (only 13 cases have been reported to date). Thiamine (75 mg/day) was commenced at a single oral dose with a rapid increase of Hb level after a few days of therapy. The insulin requirement didn't decrease during thiamine therapy, the C-peptide level after glucagon remained almost indosable. No improvement was observed in the deafness and in the optic atrophy. These findings suggest that diabetes mellitus and optic atrophy, in Wolfram's syndrome are not related to thiamine metabolism.

Autoantibodies↗
PubMed1994

Presynaptic cholinergic modulators as potent cognition enhancers and analgesic drugs. 1. Tropic and 2-phenylpropionic acid esters.

Previous studies have shown that (R)-(+)-hyoscyamine has analgesic activity as a consequence of increased ACh release following antagonism of central muscarinic autoreceptors. Since the enhancement of central cholinergic transmission could be beneficial for cognitive disorders, we manipulated (R)-(+)-hyoscyamine, synthesizing several derivatives of tropic and 2-phenylpropionic acids, with the aim of obtaining drugs which are able to increase ACh release and consequently to show analgesic and nootropic activities. The results showed that several new compounds are indeed potent analgesics (with an analgesic efficacy comparable to that of morphine) and that the most potent one ((+/-)-19, PG9) also has remarkable cognition-enhancing properties. Our study confirmed that the mechanism of action involves ACh release even if it is still unclear whether only muscarinic autoreceptors or, also, heteroreceptors are involved.

Acetylcholine↗
PubMed1994

Expression of the low-affinity NGF receptor during human muscle development, regeneration, and in tissue culture.

The expression of the low-affinity NGF receptor (LNGFR) during human muscle development, regeneration, and in tissue culture was analyzed using a murine monoclonal antibody to human LNGFR (MAb ME 20.4). Muscle cells from 12-22-week fetuses stained strongly for LNGFR. In adult normal muscle, only intramuscular nerve endings showed immunoreactivity with MAb ME 20.4, but no staining was detected in muscle fibers. In Duchenne muscular dystrophy, immunohistologically demonstrable LNGFR was present in regenerating muscle fibers. In these fibers, LNGFR gene expression was also demonstrated at the transcriptional level using in situ hybridization with riboprobes coding with human LNGFR. Cultures from human fetal and adult muscle were studied by double label indirect immunofluorescence microscopy with MAb ME 20.4 and antisera against human fetal myosin. Most myosin-positive cells, both at the myoblast and myotube stages, displayed surface LNGFR immunostaining. In cells from fetal muscle, LNGFR was detected during the first 2 weeks in vitro, whereas in cells from adult muscle the expression of LNGFR was observed for up to 7 weeks. These findings suggest a potential involvement of LNGFR in human muscle development and regeneration.

Culture Techniques↗