Transmitted drug resistance to NRTIs and risk of virological failure in naïve patients treated with integrase inhibitors

OBJECTIVES

Nucleoside reverse transcriptase inhibitor (NRTI) transmitted drug resistance mutations (TDRMs) could increase the risk of virological failure (VF) of first-line integrase strand transfer inhibitor (InSTI)-based regimens.

METHODS

Patients starting two NRTIs (lamivudine/emtricitabine plus abacavir/tenofovir) plus raltegravir or dolutegravir were selected from the EuResist cohort. The role of NRTI genotypic susceptibility score and of specific TDRMs in VF (i.e. two consecutive viral loads > 50 HIV-1 RNA copies/mL or a single viral load ≥ 200 copies/mL after 3 months from antiretroviral therapy start) was evaluated in the overall population and according to the InSTI employed.

RESULTS

From 2008 to 2017, 1095 patients were eligible for the analysis (55.5% men, median age 39 years). In all, 207 VFs occurred over 1023 patient-years of follow-up. The genotypic susceptibility score (GSS) had no effect on the risk of VF in the overall population. However, the presence of M184V/I independently predicted VF of raltegravir- but not dolutegravir-based therapy when compared with a fully-active backbone [adjusted hazard ratio (aHR) = 3.09, P = 0.035], particularly when associated with other non-thymidine analogue mutations (aHR = 27.62, P = 0.004). Higher-zenith HIV-RNA and lower nadir CD4 counts independently predicted VF.

CONCLUSIONS

NRTI backbone TDRMs increased the risk of VF with raltegravir-based but not dolutegravir-based regimens.

A13 Phylodynamic analysis of HIV in Florida

We are interested in using phylodynamics to better understand molecular clusters of HIV within the state of Florida, USA. To our knowledge, there is currently no study using such methodology to understand the epidemic in Florida. Viral sequences collected from 2007 to 2017 (about 50,000) will be linked with individual-level data (demographics—sex, race/ethnicity—and mode of transmission) accessed through the Patient Reporting Investigating Surveillance Manager (PRISM), and the Enhanced HIV/AIDS Reporting System (eHARS) via the Florida Department of Health (FDOH). Through the use of HIV-TRACE, which analyzes genetic distance matrices, we will create molecular transmission networks including data on mode of transmission, race/ethnicity, and sex. Furthermore, a maximum likelihood phylogenetic tree will be created using software (e.g. IQ-Tree, PhyML, and FastTree2) run on a high-performance cluster. Phylogenetic comparative analysis will be performed to assess the association between phylogenetic clades and demographics (including extended demographics like syphilis and other comorbidities queried from PRISM and eHARS).

A new approach to disentangle genetic and epigenetic components on disease comorbidities: studying correlation between genotypic and phenotypic disease networks

Disease comorbidity is a result of complex epigenetic interplay. A disease is rarely a consequence of an abnormality in a single gene; complex pathways to disease patterns emerge from gene-gene interactions and gene-environment interactions. Understanding these mechanisms of disease and comorbidity development, breaking down them into clusters and disentangling the epigenetic - actionable - components, is of utter importance from a public health perspective. With the increase in the average life expectancy, healthy aging becomes a primary objective, from both an individual (i.e. quality of life) and a societal (i.e. healthcare costs) standpoint. Many studies have analyzed disease networks based on common altered genes, on protein-protein interactions, or on shared disease comorbidites, i.e. phenotypic disease networks. In this work we aim at studying the relations between genotypic and phenotypic disease networks, using a large statewide cohort of individuals (100, 000+ from California, USA) with linked clinical and genotypic information, the Genetic Epidemiology Research on Adult Health and Aging (GERA). By comparing their phenotypic and genotypic networks, we try to disentangle the epigenetic component of disease comorbidity.

Incidence and predictors of cardiovascular disease, chronic kidney disease, and diabetes in HIV/HCV-coinfected patients who achieved sustained virological response

Data on the effects of sustained virologic response (SVR) to hepatitis C virus (HCV) therapy on the outcome of extrahepatic complications are scarce. We conducted this study to assess the impact of SVR on the occurrence of chronic kidney disease (CKD), diabetes mellitus (DM), and cardiovascular disease (CVD) in a cohort of human immunodeficiency virus (HIV)-infected patients. We analyzed coinfected HIV/HCV patients in the Management of Standardized Evaluation of Retroviral HIV Infection (MASTER) cohort. Only event-free patients with a serum HCV-RNA determination at baseline were included. Patients were divided into four groups: INF-exposed with SVR; INF-exposed without SVR; spontaneous HCV clearance; untreated viremic patients. We estimated the incidence of extrahepatic complications and employed Kaplan-Meier curves and Cox regression to assess the association of SVR/INF strata adjusted for a series of confounders. Data from 1676 patients were analyzed (20.29 % started an INF-based regimen). Overall, the incidence of CKD, DM, CVD, and death was 5.32 [95 % confidence interval (CI) 3.99-6.98], 10.13 (95 % CI 8.20-12.37), 6.79 (95 % CI 5.26-8.65), and 13.49 (95 % CI 11.29-16.0) per 1000 person-years of follow-up, respectively. In the Cox model for treated patients, SVR was not associated with a lower risk of CKD, DM, CVD, and death compared to non-SVR. Cirrhosis was significantly associated with a higher risk of CKD [hazard ratio (HR) 2.13; 95 % CI 1.06-4.31], DM (HR 3.48; 95 % CI 2.18-5.57), and death (HR 6.18; 95 % CI 4.1-9.31), but not of CVD (HR 1.14; 95 % CI 0.57-2.3). There are still many unknowns regarding the impact of SVR on the occurrence of extrahepatic complications in coinfected HIV/HCV patients. Further investigations are needed in order to elucidate the role of SVR as an independent prognostic factor for extrahepatic events.

Use of efavirenz or atazanavir/ritonavir is associated with better clinical outcomes of HAART compared to other protease inhibitors: routine evidence from the Italian MASTER Cohort

Randomized trials and observational cohorts reported higher rates of virological suppression after highly active antiretroviral therapy (HAART) including efavirenz (EFV), compared with boosted protease inhibitors (PIs). Correlations with immunological and clinical outcomes are unclear. Patients of the Italian MASTER cohort who started HAART from 2000 to 2010 were selected. Outstanding outcome (composite outcome for success (COS)) was introduced. We evaluated predictors of COS (no AIDS plus CD4+ count >500/mm(3)plus HIV-RNA <500 copies/mL) and of eight single outcomes either at month 6 or at year 3. Multivariable logistic regression was conducted. There were 6259 patients selected. Patients on EFV (43%) were younger, had greater CD4+ count, presented with AIDS less frequently, and more were Italians. At year 3, 90% of patients had HIV RNA <500 copies/mL, but only 41.4% were prescribed EFV, vs. 34.1% prescribed boosted PIs achieved COS (p <0.0001). At multivariable analysis, patients on lopinavir/ritonavir had an odds ratio of 0.70 for COS at year 3 (p <0.0001). Foreign origin and positive hepatitis C virus-Ab were independently associated with worse outcome (OR 0.54, p <0.0001 and OR 0.70, p 0.01, respectively). Patients on boosted PIs developed AIDS more frequently either at month 6 (13.8% vs. 7.6%, p <0.0001) or at year 3 (17.1% vs. 13.8%, p <0.0001). At year 3, deaths of patients starting EFV were 3%, vs. 5% on boosted PIs (p 0.008). In this study, naïve patients on EFV performed better than those on boosted PIs after adjustment for imbalances at baseline. Even when virological control is achieved, COS is relatively rare. Hepatitis C virus-positive patients and those of foreign origin are at risk of not obtaining COS.

Factors influencing the normalization of CD4+ T-cell count, percentage and CD4+/CD8+ T-cell ratio in HIV-infected patients on long-term suppressive antiretroviral therapy

We evaluated factors associated with normalization of the absolute CD4+ T-cell counts, per cent CD4+ T cells and CD4+/CD8+ T-cell ratio. A multicentre observational study was carried out in patients with sustained HIV-RNA <50 copies/mL. Outcomes were: CD4-count >500/mm(3) and multiple T-cell marker recovery (MTMR), defined as CD4+ T cells >500/mm(3) plus%CD4 T cells >29%plus CD4+/CD8+ T-cell ratio >1. Kaplan-Meier survival analysis and Cox regression analyses to predict odds for achieving outcomes were performed. Three hundred and fifty-two patients were included and followed-up for a median of 4.1 (IQR 2.1-5.9) years, 270 (76.7%) achieving a CD4+ T-cell count >500 cells/mm(3) and 197 (56%) achieving MTMR. Using three separate Cox models for both outcomes we demonstrated that independent predictors were: both absolute CD4+ and CD8+ T-cell counts, %CD4+ T cells, a higher CD4+/CD8+ T-cell ratio, and age. A likelihood-ratio test showed significant improvements in fitness for the prediction of either CD4+ >500/mm(3) or MTMR by multivariable analysis when the other immune markers at baseline, besides the absolute CD4+ count alone, were considered. In addition to baseline absolute CD4+ T-cell counts, pretreatment %CD4+ T cells and the CD4+/CD8+ T-cell ratio influence recovery of T-cell markers, and their consideration should influence the decision to start antiretroviral therapy. However, owing to the small sample size, further studies are needed to confirm these results in relation to clinical endpoints.

Prediction of response to antiretroviral therapy by human experts and by the EuResist data-driven expert system (the EVE study)

OBJECTIVES

The EuResist expert system is a novel data-driven online system for computing the probability of 8-week success for any given pair of HIV-1 genotype and combination antiretroviral therapy regimen plus optional patient information. The objective of this study was to compare the EuResist system vs. human experts (EVE) for the ability to predict response to treatment.

METHODS

The EuResist system was compared with 10 HIV-1 drug resistance experts for the ability to predict 8-week response to 25 treatment cases derived from the EuResist database validation data set. All current and past patient data were made available to simulate clinical practice. The experts were asked to provide a qualitative and quantitative estimate of the probability of treatment success.

RESULTS

There were 15 treatment successes and 10 treatment failures. In the classification task, the number of mislabelled cases was six for EuResist and 6-13 for the human experts [mean±standard deviation (SD) 9.1±1.9]. The accuracy of EuResist was higher than the average for the experts (0.76 vs. 0.64, respectively). The quantitative estimates computed by EuResist were significantly correlated (Pearson r=0.695, P<0.0001) with the mean quantitative estimates provided by the experts. However, the agreement among experts was only moderate (for the classification task, inter-rater κ=0.355; for the quantitative estimation, mean±SD coefficient of variation=55.9±22.4%).

CONCLUSIONS

With this limited data set, the EuResist engine performed comparably to or better than human experts. The system warrants further investigation as a treatment-decision support tool in clinical practice.

Determinants of survival in progressive multifocal leukoencephalopathy

BACKGROUND

We sought to characterize the role of immunologic, virologic, and radiologic determinants of survival in patients with progressive multifocal leukoencephalopathy (PML).

METHODS

We recorded the clinical outcome of 60 patients with PML (73% HIV+) who were prospectively evaluated between 2000 and 2007 for the presence of JC virus (JCV)-specific CD8+ cytotoxic T-lymphocytes (CTL) in blood.

RESULTS

Estimated probability of survival at 1 year was 52% for HIV+/PML and 58% for HIV- patients with PML. Patients with PML with detectable CTL within 3 months of diagnosis had a 1-year estimated survival of 73% compared to 46% for those without CTL (hazard ratio [HR] for death = 0.47, 95% confidence interval [CI] 0.13-1.75, p = 0.26). Patients with CTL response had an increased likelihood of having contrast enhancement of PML lesions and immune reconstitution inflammatory syndrome (odds ratio 3.7 and 7.8). Estimated 1-year survival was 48% in HIV+ patients with PML with CD4 count <200/microL at PML diagnosis compared to 67% in those with CD4 >200/microL (HR for death 1.41, 95% CI 0.27-7.38, p = 0.68). JCV DNA was detected in the urine of 48% and in the blood of 56% of patients with PML, but viruria and viremia were not associated with survival.

CONCLUSIONS

The presence of JC virus (JCV)-specific cytotoxic T-lymphocytes (CTL) was associated with a trend toward longer survival in patients with progressive multifocal leukoencephalopathy (PML), which was more pronounced than the impact of CD4 count in HIV+ patients with PML early after diagnosis. Despite the association of contrast enhancement and immune reconstitution inflammatory syndrome with JCV-specific CTL, these cannot be considered as surrogate markers for the prognostic value of the CTL. Strategies aiming at improving the cellular immune response may improve the course of PML.

Effectiveness of antiretroviral regimens containing abacavir with tenofovir in treatment-experienced patients: predictors of virological response and drug resistance evolution in a multi-cohort study

BACKGROUND

In treatment-naïve patients, a combination antiretroviral therapy (cART) containing tenofovir (TDF) and abacavir (ABC) with lamivudine leads to unacceptably high virological failure rates with frequent selection of reverse transcriptase mutations M184V and K65R. We explored the efficacy of at least 16 weeks of ABC + TDF-containing cART regimens in 307 antiretroviral-experienced HIV-1-infected individuals included in observational databases.

METHODS

Virological failure was defined as an HIV RNA > 400 copies/ml after at least 16 weeks of treatment. Patients had received a median of three prior cART regimens. Of these, 76% concomitantly received a potent or high genetic barrier regimen (with at least one protease inhibitor [PI]) or non-nucleoside reverse transcriptase inhibitor or thymidine analogue) while a third non-thymidine nucleoside analogue was used in the remaining patients.

RESULTS

The 1-year estimated probability of virological failure was 34% in 165 patients with HIV RNA > 400 copies/ ml at ABC + TDF regimen initiation. Independent predictors of virological failure were the absence of a potent or high genetic barrier cART, the higher number of cART regimens experienced, and the use of a new drug class. In the subset of 136 patients for whom there were genotypic resistance test results prior to ABC + TDF initiation, the virological failure (1-year estimated probability 46%) was independently predicted by the higher baseline viral load, the concomitant use of boosted PI, and the presence of reverse transcriptase mutation M41L. In 142 patients starting ABC + TDF therapy with HIV RNA pound < or =400 copies/ml, virological failure (1-year estimated probability 17%) was associated only with the transmission category. In a small subset of subjects for whom there were an available paired baseline and follow-up genotype (n = 28), the prevalence of most nucleoside analogue reverse transcriptase inhibitor resistance mutations decreased, suggesting a possible low adherence to treatment. No selection of K65R was detected.

CONCLUSION

The virological response to ABC + TDF-containing regimens in this moderately-to-heavily treatment experienced cohort was good. Higher viral load and the presence of M41L at baseline were associated with worse virological responses, while the concomitant prescription of drugs enhancing the genetic barrier of the regimen conveyed a reduced risk of virological failure. The Appendix provides the names of other members of the MASTER cohort.

Long-term follow-up of nevirapine-treated patients in a single-centre cohort

OBJECTIVES

We reviewed the safety and efficacy of nevirapine (NVP)-based therapy in all patients initiating NVP-containing combined antiretroviral therapy [cART (>or=3 drugs)] in our clinic since 1994.

METHODS

Patient characteristics and laboratory values from the start of the NVP-based cART regimen to the last available follow-up or to NVP discontinuation were retrieved from an observational database.

RESULTS

Five hundred and seventy-three patients were treated with NVP-based cART for a median of 18.4 (range 0.1-128.8) months. The 1-year cumulative estimated probability of discontinuing NVP-containing regimens for toxicity was 0.203. Only 1.9% developed a grade 3 alanine aminotransferase (ALT) elevation. Significant increases in high-density lipoprotein cholesterol were observed up to month 12 except in treatment-naïve patients, where the increase was limited to 3 months. Discontinuation because of cutaneous reaction was predicted independently by female gender [Hazard Ratio (HR) 3.21, P<0.001] and Centers for Disease Control class C (HR 0.50, P=0.012). Discontinuation because of liver toxicity was predicted independently by anti-hepatitis C virus positivity (HR 3.84, P<0.001). In patients starting NVP-containing cART with undetectable viral loads, the 5-year estimated probability of viral load >400 HIV-1 RNA copies/mL was 0.34.

CONCLUSIONS

Long-term follow-up with an NVP-containing cART showed a low rate of discontinuation caused by liver toxicity and the maintenance of virological suppression in patients switched with undetectable viral loads.

Changes in circulating levels of atrial natriuretic factor (ANF) during orthotopic liver transplantation in humans

Atrial natriuretic factor (ANF) is a 28 amino acid peptide secreted by the atrial cardiocytes. Clearance is via the lung (50%) and the liver (25%). The main stimulus to ANF secretion is atrial distension but vasoconstrictors, sympathetic stimulation, catecolamines and tachycardia are able to enhance its circulating blood levels. ANF blood concentrations were measured during orthotopic liver transplantation in six postnecrotic cirrhotic patients. Significant increases in ANF blood levels occurred at the end of the anhepatic phase (P < or = 0.02 vs baseline) associated with low cardiac filling pressures (P < or = 0.02 vs baseline) and increased systemic vascular resistances (P < or = 0.02 vs preanhepatic phase). Aldosterone blood levels showed a similar behaviour, increasing significantly (P > or = 0.001 vs baseline) at the end of the anhepatic phase. ANF fell after reperfusion of the graft and returned towards baseline values at the end of the procedure. Since most of the total body clearance of ANF is performed by the lungs, its sharp increase at the end of the anhepatic phase could be considered a counterregulatory response to vasoconstricting stimulation and to fluid-sparing mechanisms in the presence of relative hypovolaemia. Its decrease after reperfusion could be related to volume normalization and partly to the enhanced clearance performed by the newly grafted liver.

Abdominal aortic aneurysm resection following cholecystectomy and heart transplantation. Case report

The case of a patient who underwent heart transplantation and cholecystectomy in 1993 and admitted for resection of abdominal aortic aneurysm in May 1997, is reported. About 25 minutes after unclamping the abdominal aorta the patient s blood pressure fell suddenly to 70/40 mmHg. In spite of vigorous fluid administration and infusion of Dopamine and Adrenaline the hemodynamic pattern returned to normal only 15 minutes later. The authors discuss the possible explanations of this behaviour (mesenteric traction syndrome, hypovolemia) and conclude that heart transplant patients are particularly affected by hypotension. Of paramount importance remains therefore the correct evaluation of adequate filling pressures which should be maintained slightly above normal range.

[Evaluation of renal function during orthotopic liver transplantation]

BACKGROUND

Orthotopic liver transplantation (OLI) is a recognised means of therapy for endstage liver failure (ESLF). Both the preoperative alterations of renal function, closely correlated with the ESLF, and the frequent and abrupt changes of circulating blood volumes occurring during the various phases of OLT are able to significantly alter renal function during the perioperative period.

METHODS

In order to define the specific changes of renal function during the various phases of OLT, six postnecrotic cirrhotic patients undergoing their first OLT entered a prospective study protocol. All the patients had standard and anesthetic techniques including the venovenous bypass (VVBP) during the anhepatic phase. At standard intervals (baseline, during hepatic dissection, during the anhepatic phase, following reperfusion, at the end of surgery) together with complete hemodynamic and metabolic profiles, arterial blood and urine samples were obtained to determine electrolytes and creatinine concentrations, blood levels of atrial natriuretic factor, aldosterone and renin activity. Using standard formulas creatinine clearance (Ccreat) and Na absolute and fractional excretions (FeNa%) were calculated.

RESULTS

Major changes in the hemodynamic profile occurred during the anhepatic phase in spite of the use of the VVBP (reduced cardiac index, reduced pulmonary wedge pressure, increased systemic vascular resistances). Concomitantly a significant decrease in Ccreat (-67%) and in urinary output, was present while aldosterone and renin activity increased. The changes in Ccreat persisted at the end of surgery in spite of the optimal hemodynamic profile. Aldosterone and renin activity returned to values close to baseline at the end of surgery.

CONCLUSIONS

From these data it is possible to conclude that renal function markedly deteriorates during OLT and it has to be considered at increased risk in the immediate postoperative period. The use of VVBP does not seem to prevent the intraoperative renal impairment.

Lactate blood levels in the perioperative period of orthotopic liver transplantation

To investigate whether early postoperative changes in blood lactate concentration indicate the functional recovery of the newly grafted liver, changes in oxygen supply, oxygen consumption, acid-base equilibrium, and blood lactate concentrations were prospectively studied in a group of 53 postnecrotic cirrhotic patients during the various phases of orthotopic liver transplantation (preanhepatic, anhepatic, neohepatic) and for the first 48 h following reperfusion. The patients were divided into two groups according to the quality of the early graft function, as indicated by alanine aminotransferase, bile flow, and prothrombin activity: group A (49 patients), good immediate graft function and group B (4 patients), immediate graft non-function. Lactate levels rose in the same manner during the preanhepatic and anhepatic stages and peaked after revascularization of the graft. Following reperfusion, however, distinctly different blood lactate profiles were recorded in the two groups of patients. A fall in lactate concentration was recorded in group A patients, whereas a continuous rise occurred in group B patients: the difference becoming significant by the end of surgery (P < or = 0.05). During the first 48 h following revascularization of the graft, opposite trends in lactate concentration, bile flow, alanine aminotransferase, and prothrombin activity were evident in the two groups of patients: 24 h after reperfusion, lactate levels were below 2 mmol/l in 47 of 49 patients from group A, while they plateaued above 4 mmol/l in all patients from group B. Group A patients had lower alanine aminotransferase levels (P < or = 0.001), higher prothrombin activity, (P < or = 0.01), and greater bile flow (P < or = 0.02). If validated in larger series, the blood lactate profile, probably more than the absolute level, appears to be a useful indicator of the early recovery of liver metabolic capacities in the immediate postoperative period of orthotopic liver transplantation.

[Medium- and long-term use of central venous catheters in pediatrics. Personal experience]

From January 1992 to October 1994, 74 central venous catheters were inserted, in the University Hospital of Rome: Polyclinic Umberto I - "La Sapienza", in 62 paediatric patients (15.17 +/- 1.64 years old), admitted to the paediatric surgery division. The authors used a large amount of CVC: totally implanted devices (34 Groshong, 7 Broviac, 2 Hickman, 3 Port) and percutaneous catheters (28 Arrow). The choice of the infusional devices has been influenced by the length of the treatment, the primitive disease, the age and the size of the patient. The authors used totally implanted devices in paediatric patients undergoing chemotherapeutic and nutritional therapies. External central venous access devices were used in patients undergoing central catheterization lasting less than two months. The subclavian vein has been used as venous access in patients weighing > 5 kg, the internal jugular vein in < 5, kg patients. This work reports the early (PNX, hematomas, arterial access) and the long term complications (infections, accidental unthreading, occlusions and dislocations). We can say that the medium and long last term CVC is well tolerated and accepted in paediatric patients too, for antineoplastic, nutritional and infusion therapies.

Pharmacokinetic profile of the induction dose of propofol in chronic renal failure patients undergoing renal transplantation

STUDY OBJECTIVE

To define the pharmacokinetic profile of the induction dose of propofol in chronic renal failure patients.

DESIGN AND SETTING

Determination of propofol blood concentrations after the bolus dose of 2 mg.kg-1 bw injected in 30 seconds in a peripheral vein in a group of chronic renal failure (CRF) patients and in a group of normal patients (controls).

PATIENTS

10 CRF patients (7 males, 3 females, mean age 47 +/- 8 years old, mean body weight 66 +/- 8 kg) candidates to cadaveric renal transplantation and free from major hepatic diseases (study group); 8 ASA I patients (5 males, 3 females), without major cardiorespiratory, hepatic, renal, hematologic or metabolic diseases undergoing minor elective surgical procedures lasting from 50 to 90 minutes (control group).

MEASUREMENTS

a) propofol blood concentrations by means of HPLC; b) derived pharmacokinetic parameters (calculated by means of Siphar, version 4.0, Societé de informatique médicale, Simed, Paris, 1991); c) cardiovascular parameters (heart rate, central venous pressure, invasive arterial pressure).

MAIN RESULTS

The decay of propofol whole blood concentrations, distribution, redistribution and elimination half lives were similar in CRF and in control patients. On the contrary, significantly different in CRF patients were propofol blood concentrations from two to ten minutes following the induction dose (lower), the area under concentration- time curve (AUC) (smaller), the mean resident time (longer), the total body clearance (greater), the volumes of distribution at steady state and during the elimination phase (larger). The larger volumes of distribution are closely correlated with the significantly lower albumin concentrations in the uremic patients. An accelerated hepatic biotransformation is one of the possible explanations for the greater total body clearance of propofol in the uraemic patients: in fact an increased glucuronyltrasferase activity and glucuronoconjugation induced by phenols has been demonstrated in uraemia. On the other hand, large volumes of distribution are often associated with elevated total body clearance. The only significant change in the cardiovascular profile was a reduction of 17 +/- 8% of the systolic blood pressure one minute after the administration of the induction dose of propofol, whereas heart rate, arterial and central venous pressures were rather stable after intubation and at skin incision: proper vascular filling before the induction of anaesthesia has probably played a crucial role in maintaining hemodynamic stability.

CONCLUSIONS

From the data gathered in this study, propofol can be considered a suitable anaesthetic agent for the induction of general anaesthesia in uraemic patients. In our opinion these data could constitute a basis for future protocols of total intravenous anaesthesia with propofol in uremic patients.

[Effectiveness and modality of continuous infusion administration of atracurium dibesylate]

One-hundred and five patients with ASA I-II were scheduled for general surgery. Atracurium was the muscle-relaxant of choice. A bolus dose of atracurium (0.5 mg/kg-1) was administered immediately before thiopentone. After 15 minutes began the infusion of atracurium diluited in saline solution and administered through a simple infusion set. The neuromuscolar function was investigated evaluating the amplitude of response to TOF and DBS. This procedure proved to be safe, reliable and easily performed in every operating room.

Fentanyl pre-treatment does not affect the pharmacokinetic profile of an induction dose of propofol in adults

The initial disposition of propofol was reported to change when the administration was preceded by fentanyl. The pharmacokinetic profile of the induction dose of propofol (2 mg kg-1 body weight) was studied in 20 ASA I patients randomly allocated to receive fentanyl 1.5 microgram kg-1 (n = 12) or not (n = 8). Anaesthesia was maintained with isoflurane in N2O/O2. Venous blood drawn from the contralateral arm was used to determine whole blood propofol concentrations. The mean propofol blood concentrations were comparable in the two groups and were best fitted by a three exponential equation in all the patients, conforming to a three-compartment open mammillary model. Distributions (T1/2 alpha) redistribution (T1/2(7)) and elimination (T1/2 beta half-lives were comparable in the groups, without significant differences in the total body clearance in the area under the time-concentration curve (zero-infinity) in the volume of distribution at steady-state, in the volume of distribution during the elimination phase or in the mean resident time. Our data support the conclusion that pretreatment with fentanyl does not affect the pharmacokinetic profile of the induction dose of propofol in ASA I patients.

Somatomedin C (IGF I) plasma levels after orthotopic liver transplantation (OLT) in end-stage cirrhotic patients

Insulin-like growth factors [IGF I and II or somatomedins (SMS)] are polypeptides chemically and biologically correlated with insulin. The main source of synthetic activity and secretion is the liver, although many other tissues have been demonstrated to synthesize SMS. In the circulation, they are not present in a free form, but are mostly bound to a specific carrier protein independently synthesized in the liver. Hepatic or extrahepatic storage organs have not been demonstrated; the half life of the SMS-binding protein complex is between 3 and 4. Synthesis of SMS is regulated by GH, insulin, thyroxine and nutrition (caloric and protein intake, and nitrogen balance). The role of corticosteroids is still a matter of debate: in patients treated with steroids SMS blood levels have been shown to be within normal limits, while biological activity has been demonstrated to be significantly reduced by SMS inhibitors, probably induced by corticosteroid therapy. The biological properties of SMS are related to their structural homology with insulin, and can be summarized as follows: A. Insulin-like activity (glucose oxidation, lipogenesis, glycogen synthesis, inhibition of lipolysis and glycogenolysis); B. Sulphation activity (incorporation of sulphate and leucine into glycosaminglycans of the cartilage); C. Stimulation of fibroblast multiplication; D. Amplification of other hormone activities (GH); E. Complementary anabolic activity with insulin. Low levels of SMS have been demonstrated in hypopituitarism (secondary) or in other diseases independent of GH reduced secretion (primary) such as malnutrition, malabsorption, acute or chronic liver failure and uraemia. Negative nitrogen balance, hypocaloric and/or low protein diets are usually correlated with low levels of SMS. Recently, Schalch et al. reported on the role of orthotopic liver transplantation (OLT) in normalizing SMS blood levels in a group of end-stage liver diseased patients. This preliminary paper deals with changes in IGF-I plasma levels (somatomedin C) in a group of patients affected by end-stage liver cirrhosis before and after OLT.