Comparison between different referral strategies for acute ischemic stroke patients in a hub-spoke emergency stroke network: a real-world experience in south-east Lazio.

AIM: To describe different referral strategies for acute ischemic stroke (AIS) patients in a Hub-Spoke emergency stroke network with their incidence, time metrics and related outcomes. METHODS: Referral paradigms were defined as follows: primary transfer to the comprehensive stroke center (CSC) from a remote region, called mothership (MS); secondary transfer to the CSC from a primary stroke center where intravenous thrombolysis was available, called drip and ship (DS); secondary transfer to the CSC from a community hospital where no reperfusion therapy was available, called ship and drip (SD); primary transfer to the CSC from its catchment area, called direct CSC (dCSC). RESULTS: Among 517 anterior circulation AIS patients treated with mechanical thrombectomy between 2015 and 2020, 16.6% of them were SD, in addition to the well-known referral paradigms of MS (21.8%) and DS (18.1%). This rate grew to 30% when only patients whose place of onset was outside the CSC catchment area were considered. In the SD group, onset to CSC and onset to groin were significantly longer (178±80 min vs. 102±60 min, p<0.001, and 277±77 min vs. 211±61 min, p<0.001, respectively), and the risk of any intracranial hemorrhage (ICH) was significantly higher (OR: 2.514; 95%CI: 1.18-5.35, p=0.017) compared to MS. CONCLUSION: In this hub-spoke stroke network, a high proportion of SD paradigm was found, which was associated with longer times to treatment and higher rates of any ICH. A closer cooperation between hospital stroke physicians, national health system staff, and paramedics is warranted to identify the most appropriate referral strategy for each patient.

Natural language processing and String Metric-assisted Assessment of Semantic Heterogeneity method for capturing and standardizing unstructured nursing activities in a hospital setting: a retrospective study.

Background: Nurses record data in electronic health records (EHRs) using different terminologies and coding systems. The purpose of this study was to identify unstructured free-text nursing activities recorded by nurses in EHRs with natural language processing (NLP) techniques and to map these nursing activities into standard nursing activities using the SMASH method. Study design: A retrospective study using NLP techniques with a unidirectional mapping strategy called SMASH. Methods: The unstructured free-text nursing activities recorded in the Medicine, Neurology and Gastroenterology inpatient units of the Agostino Gemelli IRCCS University Hospital Foundation, Rome, Italy were collected for 6 months in 2018. Data were analyzed by three phases: a) text summarization component with NLP techniques, b) a consensus analysis by four experts to detect the category of word stems, and c) cross-mapping with SMASH. The SMASH method calculated the string comparison, similarity and distance of words through the Levenshtein distance (LD), Jaro-Winker distance and the cross-mapping's cut-offs: map [0.80-1.00] with < 13 LD, partial-map [0.50-0.79] with <13 LD and no map [0.0-0.49] with >13 LD. Results: During the study period, 491 patient records were assessed. 548 different unstructured free-text nursing activities were recorded by nurses. 451 unstructured free-text nursing activities (82.3%) were mapped to standard PAI nursing activities, 47 (8.7%) were partial mapped, while 50 (9.0%) were not mapped. This automated mapping yielded recall of 0.95%, precision of 0.94%, accuracy of 0.91%, F-measure of 0.96. The F-measure indicates good reliability of this automated procedure in cross-mapping. Conclusions: Lexical similarities between unstructured free-text nursing activities and standard nursing activities were found, NLP with the SMASH method is a feasible approach to extract data related to nursing concepts that are not recorded through structured data entry.

A nursing clinical information system for the assessment of the complexity of care.

BACKGROUND: The complexity of care can be described through a clinical nursing information system, in particular through the Professional Assessment Instrument -PAI-, encoding each health care activity in time units and analysing the relationship of observed time to patient characteristics in relation to the functional models of care needs. DESIGNS: Observational study. METHODS: Data were collected for 11 months in 2016-17 in four inpatient units of an Italian hospital using the Professional Assessment Instrument, and a survey grid to measure the time of the nursing activities delivered. All activities with a frequency of 20 or more have been included. The Work Sampling technique was used for time-tracking. RESULTS: The sample included 2765 nursing activities. The mean times for each care activity were compared showing significant differences. A statistically significant correlation (Sperman's correlation coefficient) was observed both between the observed time and the level of illness severity and between time and functional models. CONCLUSIONS: Patient complexity, both in terms of illness severity and level of dependence, can be coded through a clinical nursing information system. This facilitates the classification and measurement of nursing care delivered, which includes the entire care process.

The assessment of the complexity of care through the clinical nursing information system in clinical practice: a study protocol.

BACKGROUND: The costs of nursing staff amounts to approximately 50% of the total budget of the health workforce and accounts for 20% to 30% of the total costs incurred by the health care companies. The goal of the study, by analyzing the complexity of care, is to provide a quantification of the assistance delivered, through the assessment of the technical aspects of the welfare activities according to the variable of time. Data from these activities flow into the clinical nursing information system Professional Assessment Instrument - PAI - which is used at the health facility involved in this study. This instrument allows nurses to document the nursing process in electronic format by using a standardized nursing language (nursing diagnoses, nursing interventions and nursing outcomes). METHODS: The design of the study is observational. The participants will be patients that are hospitalized in the cardiology departments, the intensive care units for cardiac and thoracic surgery, pulmonary medicine and medical oncology of the "A.Gemelli" hospital in Rome, Italy. The observers who will carry out the surveys will be students of the nursing degree course and the coordinators of the respective wards. The times recorded for each health care activity will be correlated with variables that are defined in the literature as the indicators of the complexity of care. The research protocol was approved by the Ethics Committee of the "A. Gemelli" Hospital in June 2015. RESULTS: In terms of results, this study aims to verify the reliability of the Professional Assessment Instrument tool as a system for the classification and measurement of nursing care which includes the entire care process, taking into account all of the variables deemed crucial to the nursing care effort. CONCLUSIONS: This study will provide a tool for the assessment of the complexity of care, with the goal of improving the quality of care for the patients and of interacting with the health administration system for the management of resources.

An experience of field work learning for healthcare providers: new perspectives between disadvantages and critical issues.

INTRODUCTION: The learning models used in traditional education are not very effective for the continuing education of healthcare providers. Fieldwork learning is an active learning method that is feasible in the workplace and is also suitable for professionals who possess a style of experiential learning. Guardian Angel 2.0® is a fieldwork learning project designed to promote educational skills in nurses to improve the self-care and quality of life in women affected by osteoporosis. The purpose of this article is to present the Guardian Angel 2.0® project and its results. METHODS: The Guardian Angel 2.0® effort lasted nine months and involved 212 nurses in the north, centre and south of Italy. A socio-demographic questionnaire, an evaluation scale of the learning process and a participants' satisfaction questionnaire were used to evaluate and monitor the fieldwork learning project. RESULTS: Out of the 212 nurses who participated in the project, 119 (70%) completed it. The mean age of these participants was 48 years (± 7.98), and 83.5% were female. About half of the participants (52.0%, 55.4% and 45.0%, respectively) were good (a) at respecting deadlines, (b) at using the methodological instruments and (c) the information tools properly. Almost all nurses considered the project to be very relevant (96.4%). In regards to the project's quality, the nurses perceived it as excellent (51.0%) and very good (48.5%). Finally, the project was considered very useful or useful by 100% of nurses. CONCLUSIONS: The general satisfaction of nurses was high. The fieldwork learning was relevant and useful for developing educational skills in nurses. It would therefore be appropriate to use fieldwork learning in clinical settings to improve the existing experience of healthcare providers and thereby reduce the difficulties of transforming the knowledge from a theoretical to a practical level and to promote the development of new behaviours when the existing ones become obsolete or inefficient.

Dynamic contrast-enhanced MR evaluation of prostate cancer before and after endorectal high-intensity focused ultrasound.

PURPOSE: The authors sought to determine the diagnostic performance of dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging in the evaluation of prostate cancer before and after transrectal high-intensity focused ultrasound (HIFU) treatment. MATERIALS AND METHODS: We analysed 25 patients with prostate cancer. The prostate-specific antigen (PSA) value was evaluated 1, 4 and 6 months after treatment. DCE-MR imaging was performed the day prior to and 1, 4 and 6 months after HIFU treatment. Transrectal prostate biopsies were obtained at the time of diagnosis and 6 months after treatment. RESULTS: Before treatment, intraglandular lesions were considered to be potential sites of neoplasm and subsequently confirmed as sites of prostate adenocarcinoma in all 25 patients based on prostatespecific antigen (PSA) values and histological examinations (rho=1; p<0.001). Using histology as the gold standard, DCE-MR imaging displayed 100% sensitivity, 100% specificity, 100% positive predictive value and 100% negative predictive value before treatment. After HIFU treatment, DCE-MR imaging showed 100% sensitivity and 96% specificity. CONCLUSIONS: DCE-MR imaging can be used to visualise prostate adenocarcinoma. Several morphological and postgadolinium modifications in the follow-up DCE-MR images after HIFU treatment were also observed.

Impact of a nursing information system in clinical practice: a longitudinal study project.

BACKGROUND: The implementation of adequate clinical information systems helps to deal with the immense flow of health data to ensure the continuity of care and access to a safe and high-quality healthcare system. Currently there is an increasing awareness of the importance of evaluating and measuring the impact of such systems in clinical practice. Implementations often fail, due to inadequate interaction between technology and human elements. METHODS: This article describes a research project aimed at evaluating the impact of a clinical nursing information system (CNIS), called Professional Assessment Instrument (PAI), in clinical practice. The study will evaluate PAI Quality, Nurses Satisfaction, PAI Use, Nurses and Environment Characteristics, Net Benefits and Nurses' Experiences related to the PAI use. A theoretical model developed for this research will guide the study. A quali-quantitative longitudinal design will be performed involving two hospitals over a 9-month period. To measure different dimensions that affect the success/failure of CNIS we will use different tools/ methods of data collection (questionnaires, psychometric tools, surveys and focus groups). EXPECTED RESULTS: This study will evaluate the impact of a CNIS in hospitals providing an overview of the factors which can help and hinder the implementation of an information system. CONCLUSIONS: The results of the study will support interventions to improve and implement clinical information systems designed to computerize nursing data, with positive effects on public health and research in general, providing further evidence for health policy.

Identification and management of subvesical bile duct leakage after laparoscopic cholecystectomy: A systematic review.

Bile leak is a rare complication after Laparoscopic Cholecystectomy. Subvesical bile duct (SVBD) injury is the second cause of minor bile leak, following the unsuccessful clipping of the cystic duct stump. The aim of this study is to pool available data on this type of biliary tree anatomical variation to summarize incidence of injury, methods used to diagnose and treat SVBD leaks after LC. Articles published between 1985 and 2021 describing SVBD evidence in patients operated on LC for gallstone disease, were included. Data were divided into two groups based on the intra or post-operative evidence of bile leak from SVBD after surgery. This systematic report includes 68 articles for a total of 231 patients. A total of 195 patients with symptomatic postoperative bile leak are included in Group 1, while Group 2 includes 36 patients describing SVBD visualized and managed during LC. Outcomes of interest were diagnosis, clinical presentation, treatment, and outcomes. The management of minor bile leak is controversial. In most of cases diagnosed postoperatevely, Endoscopic Retrograde Cholangio-Pancreatography (ERCP) is the best way to treat this complication. Surgery should be considered when endoscopic or radiological approaches are not resolutive.

Deep venous thrombosis and abortion: an unusual clinical manifestation of severe form of pectus excavatum.

Pectus excavatum is a chest wall malformation with a strong psychological and aesthetic impact. Rarely, pectus excavatum patients can show respiratory or cardiac symptoms occurring mainly during physical exertion. We report a case of a 34-year-old pregnant woman with a severe degree of pectus excavatum who developed serious cardiovascular disease resulting in spontaneous twin abortion at the twenty-first week of gestation. Cardiovascular disease was resolved after open surgical correction of pectus excavatum. This case shows how a tardive diagnosis and a delayed surgical approach for pectus excavatum can lead to severe consequences.

Differentiation of normal and neoplastic bone tissue in dynamic gadolinium-enhanced magnetic resonance imaging: validation of a semiautomated technique.

PURPOSE: This study was undertaken to clinically validate the accuracy of a semiautomated software tool for analysing the enhancement curve in focal malignant bone lesions. MATERIALS AND METHODS: Twenty-three patients affected by cancer with malignant focal bone lesions underwent dynamic gadolinium-enhanced magnetic resonance (MR) imaging using the following protocol: T1-weighted turbo spin-echo sequences (time to repeat [TR] 600 ms, time to echo [TE] 8.6 ms, field of view [FOV] 40x40 cm) before and after intravenous injection of gadolinium-containing contrast agent. Image postprocessing was performed using the software DyCoH. Each region of interest (5x5 pixels), drawn to include the area of the lesion with the highest values of the area under the curve map, was analysed to obtain time-intensity curves and relative perfusion parameters: time to peak (TTP), peak intensity (PI), slope (60-s slope), intensity at 60 s after contrast agent injection (60-s I) and final intensity (FI). RESULTS: Data were obtained by analysing 86 malignant lesions and 86 apparently normal bone regions. PI, 60-s slope, 60-s I and FI were significantly different between neoplastic and apparently normal (p<0.001) samples. Sensitivity, specificity and accuracy were, respectively, 94%, 93% and 94% at a PI threshold of 100 (signal-to-noise ratio), with positive and negative predictive values of 93% and 94%. At a threshold value of 0.85 for 60-s slope, sensitivity and specificity values were both 91%. CONCLUSIONS: The semiautomated technique we report appears to be accurate for identifying neoplastic tissue and for mapping perfusion parameters, with the added value of a consistent measurement of perfusion parameters on colour-coded maps.

Incidence of new fractures in women with osteoporosis-induced vertebral fractures detected on routine lateral chest radiographs.

PURPOSE: Vertebral fractures represent one of the major complications of osteopororis. Diagnosis is followed by a pharmacological, interventional or surgical treatment. Up to day there are non practice guidelines for a screening evaluation of bone fractures in elderly and most of the fractures remain undiagnosed. We prospectively evaluated the prevalence of vertebral fractures on chest X-rays to determine the diagnostic and prognostic roles of chest X-ray in predicting new bone fractures 2 years after the initial radiogram. MATERIALS AND METHODS: Between March 2004 and October 2005, 4,045 women underwent chest X-ray in our radiology department for any indication. We identified 166 women with the presence of at least one vertebral fracture. A questionnaire was administered to these women to collect information about diagnosis of osteoporosis, history of malignancy, systemic diseases, osteoporosis-inducing drugs and pharmacological, radiological or surgical treatment received. RESULTS: Out of the 166 women (age 73+/-10.5 years) with vertebral fractures, we interviewed 101 women; 13 had died and 52 were not found. Most of the patients were on menopause (97.1%, 98/101) with an average age of menopause of 48,2 years (+/-6 years). Among the patients on menopause, 15,8% (16/101) had undergone hysterectomy. All patients received a diagnosis of osteoporosis, which was reached with a chest X-ray report in 23.7% (24/101) of cases. A new skeletal fracture occurred in 20.5% (5/27) of patients receiving treatment against a frequency of 20.8% (16/74) in patients without treatment. No statistical difference was found between the groups (p = 0.374). CONCLUSIONS: Inadequate treatment may explain the lack of a substantial difference in new fracture risk between treated and untreated patients. For these reason we discuss about the evaluation of an adeguate therapeutic approaches in prevention of osteoporosis-induced fractures.

Requirement for GD3 ganglioside in CD95- and ceramide-induced apoptosis.

Gangliosides participate in development and tissue differentiation. Cross-linking of the apoptosis-inducing CD95 protein (also called Fas or APO-1) in lymphoid and myeloid tumor cells triggered GD3 ganglioside synthesis and transient accumulation. CD95-induced GD3 accumulation depended on integral receptor "death domains" and on activation of a family of cysteine proteases called caspases. Cell-permeating ceramides, which are potent inducers of apoptosis, also triggered GD3 synthesis. GD3 disrupted mitochondrial transmembrane potential (DeltaPsim), and induced apoptosis, in a caspase-independent fashion. Transient overexpression of the GD3 synthase gene directly triggered apoptosis. Pharmacological inhibition of GD3 synthesis and exposure to GD3 synthase antisense oligodeoxynucleotides prevented CD95-induced apoptosis. Thus, GD3 ganglioside mediates the propagation of CD95-generated apoptotic signals in hematopoietic cells.

[Health-related quality of life in patients with chronic kidney disease]. / Qualita' della vita nei nefropatici.

Assessment of quality of life in patients with different degrees of chronic kidney disease is an important issue because of its impact on clinical decisions and financial resource management in the health-care system. The aim of this study was to assess whether a generic instrument like the SF-36 questionnaire is able to discriminate three different populations of patients with different degrees of renal disease (pre-ESRD, ESRD, TxR). Five hundred sixty-three patients from 12 Italian nephrology units completed the SF-36 scales by themselves. The results from these samples were compared with those from the general population. Univariate analysis and multivariate regression were used. The generic SF-36 questionnaire proved to be a powerful instrument to discriminate populations with different degrees of chronic renal failure. The quality of life of patients on dialysis is significantly worse than that of the normal population and other patients with less severe renal function impairment.

[Patient satisfaction in hemodialysis: a pilot cross-sectional analysis and a review]. / Valutazione del grado di soddisfazione da trattamento nel paziente in emodialisi: metologia di ricerca, strumenti, limiti e studio pilota trasversale.

BACKGROUND: Assessment of patient satisfaction is not performed routinely in many healthcare institutions. In this review, we discuss methodological aspects of assessment of patient satisfaction in hemodialysis. We also present a pilot study conducted in the Gambro Healthcare Italy dialysis clinics network. METHODS: Patient satisfaction was assessed in a network of hemodialysis units by using an internally validated Italian translation of the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) questionnaire. A cross-sectional analytic study design was used and data analysed with univariate and multivariate hierarchical logistic regression to explore correlates of the risk of being unsatisfied with dialysis treatment. Covariates which were considered include a series of over 20 clinical, demographic, organizational and structural aspects. In addition, unexplained inter-centre residual variability due to 'case-mix' was explored and plotted. RESULTS: Seventeen dialysis units participated in this cross-sectional analysis and 758/1001 (75.7%) provided answers to the questionnaires. There was a statistically significant association on multivariate hierarchical analysis between the risk of being unsatisfied with dialysis treatment and interdialysis body weight gain (unit of increase: 1 kg, p=0.004). On the contrary, the risk of unsatisfaction with dialysis treatment was significantly lower in patients with higher dry weight (unit of increase: 1 kg, p=0.002). Our multivariate hierarchical analysis identified some residual variability between dialysis units (n=6 outliers) which may not be explained by any of over 20 potential confounding covariates which were explored. CONCLUSIONS: Assessment of ''customer satisfaction'' is standard practice in private for profit product companies in general but needs to be increasingly recognized as a standard in both public and private providers of healthcare services. Social research methods, which are used for this type of analysis, need to be fine tuned and actively implemented in order to better understand how we may influence the quality of service we provide to our patients and the level at which they rate it.

1H NMR-visible mobile lipid domains correlate with cytoplasmic lipid bodies in apoptotic T-lymphoblastoid cells.

The presence of nuclear magnetic resonance (NMR)-visible mobile lipid (ML) domains in apoptotic lymphoblasts suggests alterations in neutral lipid metabolism and compartmentation during programmed cell death. The detection of similar ML signals in activated lymphocytes raises questions about common mechanisms of ML formation during apoptosis and upon lymphoblast stimulation. Structure and subcellular localization of ML domains were therefore investigated by NMR, fluorescence and electron microscopy in Jurkat T-lymphoblasts either induced to apoptosis (by anthracyclines or dexamethasone or by serum deprivation) or activated by phorbol myristate acetate (PMA) plus ionomycin. ML contents in drug-treated cells correlated linearly with apoptosis, irrespective of the specific inducer and cell cycle arrest phase (r = 0.993, P < 0.001). Similar ML levels were measured in drug-induced apoptotic cells (A approximately 30-40%) and in non-apoptotic PMA/ionomycin-treated lymphoblasts (72 h). Lower ML contents were instead formed in serum-deprived apoptotic cells, with respect to controls. Increases in ML signals were associated, in either apoptotic or activated cells, with the accumulation of cytoplasmic, osmophilic lipid bodies (diameter < or = 1.0 microm), surrounded by own membrane, possessing intramembrane particles. The results support the hypothesis that ML are formed in the cytoplasm of drug-induced apoptotic cells during an early, 'biochemically active' phase of programmed cell death.

Possible involvement of tumour cell membrane gangliosides in platelet-tumour cell interactions.

The possible correlation(s) between platelet proaggregating activity, and sialic acid content and ganglioside expression of six human colorectal tumour cell lines (CBS, GEO, HT-29, WiDr, MIP and DLD-1) was evaluated. The three cell lines (HT-29, WiDr and DLD-1) capable of inducing remarkable in vitro platelet aggregation, had significantly higher amounts of lipid-bound sialic acid than those cell lines characterised by a lower platelet proaggregating activity (GEO, CBS and MIP). High performance thin-layer chromatography demonstrated the presence of one band comigrating with GM3 in all cell lines, while GD1a and GT1b comigrating gangliosides were present only in HT-29, WiDr and DLD-1 cells. Finally, an increased platelet pro-aggregating activity of GEO and CBS cell lines was observed after the incorporation of exogenous gangliosides. The present data support the hypothesis that lipid-bound sialic acid may be involved in platelet-tumour cell interactions.

Detection of antiphospholipid antibodies by immunostaining on thin layer chromatography plates.

There is increasing interest in the role of antiphospholipid antibodies in the so-called 'antiphospholipid antibody syndrome' (APS). The two major methods currently employed for detecting the autoantibodies are the solid phase ELISA and the LAI test (inhibition of phospholipid dependent coagulation assay). In our study we have tested the possibility of detecting antiphospholipid antibodies by immunostaining on thin layer chromatography (TLC) plates, since this technique permits the use of pure phospholipid molecules as antigen. Sera were collected from 20 patients with SLE without APS, 20 patients with APS, 20 anti-HIV positive subjects, ten patients with signs of APS but antiphospholipid negative (ELISA), 20 patients with syphilis and 40 matched blood donors. Results showed that only 72.3% of sera containing detectable levels of aCL antibodies in solid phase ELISA were also positive for aCL in TLC immunostaining; these discrepancies may be due to the presence of antibodies reacting with a protein complexed with phospholipid (beta 2-glycoprotein-I) or, alternatively, to the different antigenic presentation of phospholipids on chromatograms compared to the surface of microtitre wells. Furthermore, aCL monoclonal antibody CAL-3, as well as nine sera positive for aCL, also reacted with PS and PE. Previous absorption of these sera with CL micelles completely abolished the reactivity with PS and PE, demonstrating cross-reactivity among these three phospholipids. In conclusion, our findings reveal that TLC immunostaining is more specific, but less sensitive, than ELISA for the detection of antiphospholipid antibodies in human sera.

Intracellular metabolism of 3'-azido-3'-deoxythymidine (AZT): a nuclear magnetic resonance study on T-lymphoblastoid cell lines with different resistance to AZT.

This paper reports the results of 31P and 1H nuclear magnetic resonance (NMR) studies on the uptake and phosphorylation of 3'-azido-3'-deoxythymidine (AZT) in the human CD4+ T-lymphoblastoid cell line CCRF-CEM (CEM-1.3) and in its AZT-resistant cell variant MT-500, isolated by prolonged culturing of CEM cells in the presence of increasing AZT concentrations. After 3 hr of incubation in the presence of 0.5 mM AZT, both AZT and its monophosphorylated form (AZT-MP) could be detected in the sensitive cell line in concentrations above the NMR detection levels. In another cell line, MOLT-4, which is less sensitive to AZT effects, the intracellular level of AZT-MP was much lower and was only slightly raised by increasing the concentration of AZT in the extracellular and intracellular compartments. In the AZT-resistant clone MT-500, characterized by a very low thymidine kinase (TK, EC 2.7.1.21) activity with respect to the parental clone, the intracellular AZT-MP concentration was below detection (<0.02 nmol/10(6) cells). Since, however, not only AZT-MP but also AZT signals failed to be detected in MT-500 extracts following cell incubation with AZT, it was concluded that a TK deficiency cannot be the exclusive mechanism of AZT resistance in these cells. The possible effects of additional mechanisms of drug resistance, such as specific AZT cell extrusion and limited permeation, are discussed, together with the new prospects offered by NMR spectroscopy to further evaluate the limiting steps for the utilization of antiretroviral nucleoside analogues.

Status and significance of testing for hepatitis B surface antigen and surface antibody.

Following Blumberg's discovery of hepatitis B surface antigen (HBsAg), many attempts have been made to develop several in vitro diagnostic techniques for the detection of this antigen and its homologous antibody. The two-dimensional micro-Ouchterlony immunodiffusion has been the first technique used, rapidly replaced by procedures of increasing sensitivity characterized as second-generation and the currently available third-phase tests which include radioimmunoassay (RIA), reverse passive haemagglutination (RPHA), reverse passive latex agglutination (RPLA) and enzyme immunoassay (EIA). Among these, RIA appears to be the most sensitive and specific, whereas EIA, RPHA and RPLA have the advantage of long shelf-life of stable reagents, no need for sophisticated and expensive equipment and no hazard associated with the handling of radioactive isotopes. Moreover, the sensitivity of EIA should increase by objective reading with a colorimeter. The most sensitive method for the detection of surface antibody (anti-HBs) is again RIA, whereas passive haemagglutination (PHA) had the advantage of providing titres. Finally EIA, based on inhibition of a known amount of HBsAg, has at least the same sensitivity as PHA, but has the advantage that reagents are more stable and that it permits screening for both HBsAg and anti-HBs with the same reagents at the same time. The application of these highly sensitive techniques for the detection of HBsAg and anti-HBs has resulted in a consistent reduction in the incidence of post-transfusion hepatitis type B and in a better understanding of the aetiology, epidemiology and natural history of this infection.

Protein S and HIV infection. The role of anticardiolipin and anti-protein S antibodies.

It has recently been reported that a large proportion of patients with HIV infection have low free protein S levels. In this study we show that protein S (PS) activity levels, as well as PS antigen (Ag), were significantly lower in 35 HIV-1 infected patients than in the control population (p < 0.001). When we divided HIV infected patients into three groups according to their CD4+ counts, we found that PS levels were significantly lower in patients with < 100 CD4+ cells/ul. In order to investigate the possible role of (auto)immune response in the pathogenesis of PS deficiency, the presence of anticardiolipin antibodies (aCL) and/or of the specific antibodies to protein S was evaluated. A high prevalence (77.1%) of aCL in both symptomatic and asymptomatic subjects was observed. The screening for specific anti-PS antibodies, performed by immunoblotting, showed an overall positivity of 28.6% in anti-HIV+ patients, with a higher prevalence in symptomatic than in asymptomatic patients. Interestingly, the prevalence of the positivity for anti-PS antibodies was found to be higher in anti-HIV+ patients with PS levels < 50%. Taken collectively, our findings suggest that at least one of the mechanisms through which PS levels are decreased in HIV infection, is due to the presence of specific autoantibodies.