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Biomedical subjects

P Di Marco

Publications and source records attributed to P Di Marco.

At least 19 recordsLinked to original sources
PubMed2005

Photophysics of an electrophosphorescent platinum (II) porphyrin in solid films.

We examine electronic processes in platinum (II) octaethyl porphyrin (PtOEP) embedded in an organic solid state matrix and in the form of vacuum-evaporated neat films in conjunction with potential applications of this compound to organic photovoltaic and electrophosphorescent devices. Absorption, photoexcitation, and luminescence spectra indicate the excitonic dimers to be dominant excited states, and their dissociation underlies the charge photogeneration process. Different charge separation distance (1.5 nm and 2.6 nm) in opposite charge carrier pairs preceding dissociation can be distinguished based on the fit of the three-dimensional Onsager theory of geminate recombination to electromodulated luminescence and photoconduction measurements. The near-positive electrode concentrated triplet dimer excitons, produced by strongly 370 nm absorbed light in neat PtOEP films, are efficiently quenched by electron transfer to the metal (Al), generating the positive charge with an efficiency eta+ exceeding 0.15 at high electric fields and dominating the measured photocurrent. Their dissociation efficiency in the bulk, eta- (negatively biased illuminated electrode), is more than one order of magnitude lower than eta+. The dissociation of singlet dimer states dominates the bulk photogeneration process induced by the weakly-absorbed light at 450 nm, with comparable eta+ and eta-. The "hot excited state" underlying the temperature-increasing emission at 540 nm has been attributed to the upper excitonic component Q+ of the first absorption band Q consistent with the exciton concept applied successfully to the interpretation of all dimer-underlain spectroscopic features of PtOEP samples studied.

Journal Article↗
PubMed2004

Fenoldopam mesylate and renal function in patients undergoing liver transplantation: a randomized, controlled pilot trial.

To test the relative effects on serum creatinine (CRE), blood urea nitrogen (BUN), and urine output of small-dose dopamine and fenoldopam in patients undergoing liver transplantation, we randomized 43 patients to 1 of 2 continuous infusions over 48 h, starting with anesthesia induction: fenoldopam, 0.1 microg . kg(-1) . min(-1) or dopamine, 2 microg . kg(-1) . min(-1). We used predetermined hemodynamic and intravascular volume goals (intrathoracic blood volume index 800-1000 mL/m(2), extravascular lung water index <7 mL/kg) to manage patients with an algorithm for use of mannitol and furosemide to maintain urine output >1 mL . kg(-1) . h(-1). At postoperative day 3, the median CRE increase was 0.2 mg/dL (interquartile range [IQR] -0.2-0.5) with fenoldopam and 0.5 mg/dL (IQR 0.3-0.9, P = 0.004) in the dopamine group. The BUN increase was median 2 mg/dL (IQR -2-8) versus 8.5 mg/dL (IQR 5-12, P = 0.01), respectively, with fenoldopam versus dopamine. Urine output was similar; however, significantly fewer fenoldopam patients required furosemide compared with dopamine patients (median 1 [IQR 0-3] versus 3 [IQR 2-4], respectively, P = 0.003). The hemodynamic effects of dopamine and fenoldopam were similar. Compared with dopamine, in the setting of liver transplantation, fenoldopam is associated with better CRE and BUN values.

Acute Kidney Injury↗
PubMed2002

Pool film boiling experiments on a wire in low gravity: preliminary results.

This paper reports preliminary results for pool film boiling on a wire immersed in almost saturated FC72 recently obtained during an experimental campaign performed in low gravity on the European Space Agency Zero-G airplane, (reduced gravity level 10(-2)). This is part of a long-term research program on the effect of gravitational and electric forces on boiling. The reported data set refers to experiments performed under the following conditions: (1) Earth gravity without electric field, (2) Earth gravity with electric field, (3) low gravity without electric field, and (4) low gravity with electric field. Although a decrease of gravity causes a heat transfer degradation, the electric field markedly improves heat exchange. This improvement is so effective that, beyond a certain field value, the heat flux is no longer sensitive to gravity. Two main film boiling regimes have been identified, both in normal and in low gravity: one is affected by the electric field and the other is practically insensitive to the field influence.

Journal Article↗
PubMed2002

Post-thoracotomy analgesia: epidural vs intravenous morphine continuous infusion.

BACKGROUND: We compared thoracic morphine epidural analgesia (TEA) and I.V. analgesia (IVA) with morphine, in respect to the time to extubation, the quality of postoperative analgesia, side effects, complications, postoperative hospital length of stay in patients having thoracotomy lung resection. METHODS: We prospectively studied 563 consecutive patients, undergoing thoracotomy (lobectomy, bilobectomy or pneumonectomy), randomized in two groups: TEA 286 patients and IVA 277 patients. In the epidural group, before the induction of anesthesia, continuous infusion of 15 mg of morphine in 250 mL of normal saline at 5 mL/h was started. In the IVA group a continuous infusion of 30 mg of morphine associated with 180 mg ketorolac in 250 mL of normal saline at 5 mL/h was started before the induction of anesthesia. The pain degree was evaluated on an analogic scale by Keele modified at 1 (end of anesthesia) 6, 12, 24, and 48 postoperative hours, at rest and after movements. Data obtained were analysed by means of the analysis of variance for repeated measures. RESULTS: The time from the end of surgery to tracheal extubation was similar in both groups. Significantly lower numeric verbal pain scores at rest and after movements were found in the epidural group (p<0.001). Postop complications, nausea and vomiting were higher in the IVA group (p<0.05). Postoperative mean hospital length of stay was 9+/-4 days in TEA and 11+/-4 in the IVA group (p<0.05). CONCLUSIONS: In our study the epidural root was superior in terms of analgesia, side effects, length of stay and postoperative complications after thoracotomy.

Analgesia, Epidural↗
PubMed2001

Pediatric renal transplantation: anesthesia and perioperative complications.

The appropriate choice of anesthesia for patients (pts) undergoing renal transplantation (Ktx) requires minimal toxicity and accurate monitoring for pts at high risk for metabolic, cardiovascular, and respiratory perioperative complications. We evaluated the anesthetic management and postoperative follow-up in pediatric Ktx performed in the last 12 years in our institution. From 1988 to 1999, 75 ASA class II-III pts (45 males, 22 females) younger than 18 years scheduled for Ktx were studied: 49 received a graft from a cadaveric donor (CD) and 26 from a living donor (LD). All pts were treated with dialysis within 24 h before the procedure. Standard monitoring consisted of an electrocardiogram, central venous pressure, non-invasive arterial pressure, pulse oximetry, and inspiratory and expiratory gas analysis. If necessary, an arterial cannula and pediatric pulmonary catheter were introduced. Anesthesia was induced with sodium thiopental, propofol, halothane, or sevoflurane and maintained with isoflurane and/or fentanyl and droperidol in O2:N2O (FiO2 0.4%). As muscle relaxants atracurium or cisatracurium besilate were used, except in allergic pts, in whom vecuronium or rocuronium bromide was administered. Dopamine, 20% mannitol, and furosemide were used to increase diuresis. Continuous morphine and ketoralac infusions were used for postoperative pain relief. The surgical technique was the same in all cases. Complications and renal-function (RF) recovery were evaluated relating to CD and LD using the chi-square test; differences in mean anesthesia and surgical time were evaluated by Student's t-test; survival curves were calculated from the day of Ktx to death or last follow-up and estimated by the Kaplan-Meier method. Values of P below 0.05 were considered significant. Postoperative immunosuppressive therapy was based on cyclosporine together with other conventional drugs. Mean anesthesia time was 228 +/- 65 min. Mean kidney ischemia time for CD was 16.5 +/- 4 h. Four pts (3 CD, 1 LD) died within 72 h postoperatively: 3 due to cardiac failure and 1 to metabolic coma. Six pts showed cardiovascular and 3 had infective complications, all successfully treated. Three pts (2 CD, 1 LD) died within 2 to 12 months after, surgery; 10 (6 CD, 4 LD) had graft failure and are still alive on dialysis; 58 (38 CD, 20 LD) are alive in good health after a mean follow-up of 57.6 +/- 36.6 months (range 12-120 months). Fifteen of 26 pts younger than 12 years (21 CD and 5 LD) recovered RF intraoperatively (10 CD, 5 LD); 1 with CD and 1 with LD showed postoperative graft failure and 2 with CD died within 72 h postoperatively, 22 (18 CD and 4 LD) are alive in good health. This group showed no statistical difference compared to pts older than 12 years. Of 16 pts (15 CD and 1 LD) with body weight (BW) less than 25 kg, 6 showed intraoperative (5 CD, 1 LD) recovery of RF. The 3 deaths were all in CD pts, 2 within 72 h and one 2 months after surgery; only 1 LD had postoperative graft failure. Twelve pts (75%) (12 CD, 80%) are alive in good health. Compared to pts with BW of 25 kg or more, this group showed lower intraoperative recovery of RF (P < or = 0.05). No peri- and postoperative complications occurred in all 26 LD pts (100%). Recent advances in surgery, anesthesia, immunosuppression, and antimicrobial prophylaxis have made Ktx a more predictable procedure even in pediatric pts. For high-risk pts, mortality and morbidity can be controlled by accurate surgical, anesthetic, and postoperative management. Pts younger than 12 years and with BW less than 25 kg are more likely to develop peri- and postoperative complications.

Adolescent↗
PubMed2001

Inhaled nitric oxide administration during one-lung ventilation in patients undergoing thoracic surgery.

OBJECTIVE: To evaluate the effects of inhaled nitric oxide (iNO) on hemodynamics and oxygenation during one-lung ventilation (OLV) in the lateral decubitus position in patients undergoing elective thoracic surgery. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Thirty consecutive patients scheduled for thoracotomy. INTERVENTIONS: Anesthesia consisted of thoracic epidural analgesia combined with general anesthesia (isoflurane, fentanyl, and vecuronium bromide). Systemic and pulmonary circulations were monitored with a radial artery catheter and a pulmonary artery catheter. Inhaled NO, 40 ppm, was administered during OLV, and the inhaled gas mixture was monitored for NO and nitrogen dioxide (NO2). Hemodynamic and oxygenation data were collected before and during inhaled NO administration. MEASUREMENTS AND MAIN RESULTS: Inhaled NO caused a reduction of pulmonary vascular resistance index from 249 +/- 97.6 dyne. sec. cm(-5) to 199.3 +/- 68.9 dyne. sec. cm(-5) (p < 0.05), without effects on systemic hemodynamics or impairment of oxygenation. A stratification of the patients according to values of QS/QT (< 30%, 30% to 44%, > or = 45%), PaO(2)/fraction of inspired oxygen (> or = 200, 100 to 199, < 100), and pulmonary hypertension (mean pulmonary arterial pressure < 24 or > or = 24 mmHg) showed that inhaled NO causes a significant reduction of mean pulmonary artery pressure in patients with pulmonary hypertension, mainly as a result of a reduction of pulmonary vascular resistance index, and improves oxygenation by reducing intrapulmonary shunt in patients with severe hypoxemia during OLV. CONCLUSIONS: Inhaled NO administration neither significantly decreased mean pulmonary arterial pressure in patients with normal pulmonary artery pressure nor improved oxygenation in nonhypoxic patients. Nevertheless, inhaled NO is effective in patients with pulmonary hypertension and hypoxemia during OLV.

Aged↗
PubMed2001

Role of pre-emptive analgesia in reduction mammaplasty.

Pre-emptive analgesia is an antinociceptive treatment that prevents altered central excitability from high intensity noxious stimuli. The aim of this study was to evaluate the efficacy of pre-emptive analgesia in patients due to have elective breast reduction that usually requires drugs for postoperative pain control. Sixty women, ASA grades I-II, were randomly divided into two groups: 30 patients were given ropivacaine infiltration 1.5 mg/ml plus adrenaline 1/200,000 in normal saline 100 ml before the skin incision, and 30 had normal saline 100 ml plus adrenaline 1/200,000 infiltrated. Postoperative pain was evaluated by an observer who was unaware of the treatment given, and scored on a visual analogue score (VAS) during the first 72 hours postoperatively. Analgesic requirements were recorded. There was a statistically significant difference between groups in the amount of additional pain control required during the early postoperative period, which suggests that pre-emptive analgesia reduces pain after reduction mammaplasty.

Adult↗
PubMed2001

[Anesthesia for lung volume reduction surgery].

BACKGROUND: Lung volume reduction surgery (LVRS) has become a novel palliative procedure for a subgroup of patients with advanced non-bullous emphysema. METHODS: Seventy-six patients with severe emphysema were evaluated: ten patients were considered for lung transplantation and only 24 underwent LVRS. In all patients an epidural catheter was inserted between the T5-T9 space. During one lung ventilation (OLV), ventilatory setting was adjusted to avoid air trapping and/or dynamic hyperinflation and high frequency jet ventilation was used when PaO2/ FiO2 was lower than 60 mmHg in 5 patients. Permissive hypercapnia (PaCO2=53 mmHg) was allowed to avoid hyperinflation and reach hemodynamic stability. RESULTS: During OLV PaO2/FiO2 was 148+/-80 mmHg, PaCO2 53+/-11 mmHg, mPA 27+/-2 mmHg and Qsp/Qt was 38+/-6%. Although the high risk patients, there were no complications due to hypercapnia during surgery. Twenty-three patients were extubated successfully at the end of the surgery (PaO2/FiO2 179+/-34 mmHg and PaCO2 59+/-11 mmHg) and only one patient was not extubated because of air leakage and died for postoperative respiratory failure after 20 days. Another patient died because of sepsis after 15 days. Numeric Ordinal Verbal Scale (by Keele modified) was used for postoperative pain degree at 0, 12th and 24th hours. No patients had pain>2. CONCLUSIONS: In conclusion, a careful anesthesia technique with an accurate intraop monitoring associated with thoracic epidural analgesia even in Video Assisted Thoracic Surgery is suggested in LVRS patients; 12 months postoperative data confirm the validity of the procedure (FEV1 24 AE 36%, FVC 53 AE 70%, RV 265 AE 199% and 6MWT 213 AE 330 m).

Adult↗
PubMed1999

Further study on the specificity and incidence of neutralizing antibodies to interferon (IFN) in relapsing remitting multiple sclerosis patients treated with IFN beta-1a or IFN beta-1b.

The development of neutralizing antibodies (NAbs) to interferon (IFN) is a common phenomenon of IFN beta therapy for relapsing-remitting multiple sclerosis (RRMS) patients. Here we examine the specificity of NAbs developed during therapy for RRMS with recombinant interferon (rIFN) beta-1a or rIFN beta-1b, and study the effect of switching from rIFN beta-1a to rIFN beta-1b on the incidence and specificity of NAbs. The relative ability to neutralize rIFN beta-1a and beta-1b was assayed in sera positive for NAbs derived from RRMS patients treated with either rIFN beta-1a (N=9) or rIFN beta-1b (N=16), while the incidence and specificity of NAbs to IFN beta developed during therapy were studied in 50 RRMS patients who were treated for two years with rIFN beta-1a followed by a further year either switching to rIFN beta-1b (N=34) or continuing treatment with rIFN beta-1a (N=16). The results show that all positive sera, independent of the source, may recognize both forms of rIFN beta and that a further year of treatment does not significantly affect the incidence and specificity of the NAbs developed during the first two years of treatment even if treatment is switched to a different type of IFN beta. The data then suggests that it is unlikely that the administration of rIFN beta-1b to anti-rIFN beta-1a NAbs-positive patients can overcome the inhibitory effect exerted by the serum antibodies (and vice versa), and that a further period of treatment with IFN beta-1b in patients previously treated with rIFN beta-1a does not significantly change the pattern of antibody response to IFN beta.

Adjuvants, Immunologic↗
PubMed1999

Calcium chloride minimizes the hemodynamic effects of propofol in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To assess the hemodynamic effects of propofol and the counteracting effect of calcium chloride (CaCl2) in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Prospective, randomized study. SETTING: University hospital, department of cardiac surgery. PARTICIPANTS: Fifty-eight patients undergoing elective CABG, divided into group A (n = 29) and group B (n = 29). INTERVENTIONS: Anesthesia was induced with a combination of fentanyl, 7 microg/kg; pancuronium, 0.1 mg/kg; and propofol, 1.5 mg/kg, administered over 60 seconds. A blinded investigator administered saline in group A patients and 10 mg/kg of CaCl2 in group B patients at the same speed and same time as propofol administration through another lumen of the central venous catheter. MEASUREMENTS AND MAIN RESULTS: Hemodynamic data were obtained at baseline (T0), 2 minutes after anesthesia induction (T1), and 2 minutes after tracheal intubation (T2). Heart rate decreased significantly in group A patients (86.2+/-11.3 beats/min at T0 and 72.8+/-7.5 beats/min at T2; p < 0.001). Mean arterial pressure decreased significantly in patients in both groups (group A, 108.0+/-12.0 mmHg at T0; 74.6+/-14.6mmHg at T2;p < 0.001 and group B, 106.0+/-10.2 mmHg at T0; 90.4+/-10.0 mmHg at T2; p < 0.05). Stroke volume index, cardiac index, and cardiac output decreased in group A patients (39.4+/-4.1 mL/beat/m2 at T0 and 28.8+/-5.2 mL/beat/m2 at T2; p < 0.05; 3.4+/-0.6 L/min/m2 at T0 and 1.9+/-0.3 L/min/m2 at T2; p < 0.001; 5.9+/-0.9 L/min at T0 and 3.4+/-0.4 L/min at T2; p < 0.001, respectively), whereas in group B patients, changes were negligible (38.1+/-7.0 mL/beat/m2 at T0 v 35.7+/-6.6 mL/beat/m2 at T2; (NS) 3.3+/-0.5 L/min/m2 at T0 v 2.7+/-0.3 L/min/m2 at T2; (NS) 5.7+/-0.9 L/min at T0 v 4.7+/-0.5 L/min at T2; (NS), respectively). CONCLUSION: Simultaneous administration of CaCl2 during the induction of anesthesia minimizes the potential negative effect of propofol on cardiac function in cardiac patients.

Anesthetics, Intravenous↗
PubMed1992

Cyclophosphamide plus vincristine and prednisone in the treatment of severe pemphigus vulgaris refractory to conventional therapy.

Five patients with severe pemphigus vulgaris refractory to conventional therapy with azathioprine and corticosteroids were treated with cyclophosphamide, vincristine and prednisone. One patient was not evaluable, while the remaining four patients showed a complete response. Duration of response was in the range of 13-94 months. Toxicity was mainly represented by alopecia, myelosuppression and gastrointestinal side-effects such as nausea/vomiting. Although cyclophosphamide and vincristine may induce severe side-effects, this association may be useful in controlling severe disease resistant to previous conventional therapies.

Adolescent↗
PubMed1991

Spontaneous release of interferon gamma by intestinal lamina propria lymphocytes in Crohn's disease. Kinetics of in vitro response to interferon gamma inducers.

The spontaneous induced release of interferon gamma (IFN gamma) by cultured intestinal lamina propria lymphocytes was investigated in patients with Crohn's disease. In contrast to normal lymphocytes, intestinal lymphocytes from these patients spontaneously released IFN gamma and seemed to contain IFN gamma in their cytoplasm. Autologous peripheral lymphocytes did not release IFN gamma. When stimulated with interferon inducers lamina propria lymphocytes from Crohn's disease tissue showed an increase in IFN gamma release 24 hours after induction with no appreciable further increase over the next two days of culture, while in control cells, either peripheral or intestinal, IFN gamma release progressively increased, peaking 72 hours after induction. These findings indicate that in Crohn's disease the intestinal lymphocytes are stimulated in vivo to produce IFN gamma and that the spontaneous IFN gamma production is compartmentalised to the gut lymphocytes. These data support the concept that locally released IFN gamma has a crucial role in cell interactions in the lamina propria and contribute to the locally occurring immune phenomena in Crohn's disease, including the increased epithelial expression of major histocompatibility complex class II antigens.

Cell Membrane↗
PubMed1990

Soluble interleukin-2 receptor in vitro production by mononuclear cells from Hodgkin patients.

Lymphocytes of patients with Hodgkin's disease have a deficient production of Interleukin-2. Recently, a soluble form of the receptor for IL-2 has been demonstrated in human sera and in vitro-stimulated culture supernatants from human T lymphocytes. In the present paper we report the production of soluble IL-2R from peripheral blood mononuclear cells in H.D. The unstimulated MNC of patients released more sIL-2R than controls. No difference was observed between PHA-stimulated MNC of patients and controls. These preliminary findings suggest that soluble IL-2R may be provide a new tool for the study of immunological dysregulation in H.D.

Adolescent↗
PubMed1989

Analysis of human dysplastic haematopoiesis in long-term bone marrow culture.

In this paper we have analysed the behaviour of myelodysplastic marrow in a long-term bone marrow liquid culture system (LTBMC) from eleven patients with myelodysplastic syndromes with regard to cellularity, day-7 and day-14 CFU-GM growth, cluster formation, adherent cells and CFU-F formation. An altered CFU-GM pattern was found in 64% of cases at diagnosis, while normal growth was seen in the remaining cases, all of which were affected by refractory anaemia. The levels of CFU-GM, as well as cellularity, were reduced in myelodysplastic marrows compared to normal controls over the whole duration of LTBMCs. Cases with a normal CFU-GM level at diagnosis also showed pathological behaviour when examined in LTBMC. The duration of dysplastic haematopoiesis was significantly shorter than that of controls. The proliferative ability of CFU-F was reduced in 50% of cases as shown by replating experiments. In conclusion, myelodysplastic marrow shows an abnormal behaviour in LTBMC, even in those cases which present normal CFU-GM growth at diagnosis.

Aged↗