Including environmental and social sustainability in the planning process of healthcare services: A case study of cancer screening programs in an inner area in Italy

Healthcare systems plan their activities to achieve efficiency and effectiveness, without addressing environmental and social sustainability. This paper describes a new approach adopted in Italy to plan and deliver health prevention services in an inner area of the Tuscany region (in Italy) to guarantee proximity of care and environmental and social sustainability. The project examines the design and delivery of cancer screening programmes using a mobile screening unit to maximise social benefits while minimising environmental waste. A cost analysis was developed to estimate the difference in CO2 equivalent emissions, travel costs, and productivity losses, comparing the current screening programmes against the introduction of a comprehensive full-service mobile screening unit. The results indicate that the new service model reduces direct non-medical costs incurred by the population and improves environmental sustainability. This alternative can reduce, annually, over 95,000 euros in terms of travel costs and productivity losses, as well as 35 tons of CO2-equivalent travel emissions for a population of 59,000 inhabitants in a mountainous area with around 6000 people involved in the screening programme. The study supports the need to adopt a new planning methodology that considers environmental, social, and financial sustainability jointly in the provision of public health services in rural areas.

Unmet needs in end-of-life care for heart failure patients

OBJECTIVE

To investigate end-of-life (EoL) care for heart failure (HF) in Tuscany (Italy) from healthcare professionals' perspective and identify areas for intervention.

METHODS

All the directors of Cardiology units (n = 29) and palliative care (PC) units (n = 14) in Tuscany were surveyed on the practices of EoL care.

RESULTS

Forty-five percent of cardiologists reported that their hospital had some EoL care services for HF patients. However, 75% did not have a multidisciplinary team providing EoL care for HF patients. Sixty-four percent stated that <25% of patients who might benefit from PC did receive it, and 18% stated that no patient received PC. For most of PC specialists, HF patients accounted for <25% of their patients. PC specialists believed that patients with cancer diseases were much more likely to receive PC than HF patients at EoL, and 36% judged that almost no HF patients were timely referred to hospice care. The majority of PC specialists reported that almost no HF patient prepared advance healthcare directives, as opposite to 57% for cancer patients, suggesting poor understanding or acceptance of their terminal condition.

CONCLUSIONS

The management of HF patients in the EoL stage in Tuscany is often suboptimal. EoL care should be implemented to ensure an adequate quality of life to these patients.

Presence and Role of Associations of Cancer Patients and Volunteers in Specialist Breast Centres: An Italian National Survey of Breast Centres Associated with Senonetwork

This article aims to present the results of a national, cross-sectional, voluntary, online survey on the presence and roles of associations of breast cancer patients and volunteers in Italian specialist breast centres. The survey was developed according to standard methods. The questionnaire was pre-tested by a random sample of three breast centres, loaded onto the SurveyMonkey platform, and piloted by one volunteer breast centre. The breast centre clinical leads were invited to participate via email. A link to the online instrument was provided. No financial incentives were offered. The results were reported using standard descriptive statistics. The response rate was 82/128 (65%). Members of associations were routinely present in 70% Italian breast centres. Breast centres most often reporting their presence were those certified by the European Society of Breast Cancer Specialists. Patient support (reception and information, listening, identification of needs, and psychological support) was the primary area where associations were reported to offer services. The magnitude of this phenomenon warrants a study to investigate the impact of the activities of associations on the quality of life of patients and on the cost-benefit ratio of the service, and the modes of their interactions with the nursing staff and the medical staff.

Quality of life and satisfaction of patients after oncoplastic or traditional breast-conserving surgery using the BREAST-Q (BCT module): a prospective study

INTRODUCTION

The oncoplastic conservative surgery was developed as a natural evolution of traditional surgery, attempting to improve the therapeutic and aesthetic outcomes where tumor resection could be followed by not-adequate results. Our primary aim is to evaluate how patient satisfaction and quality-of-life after conservative oncoplastic surgery, using BREAST-Q (BCT Module), change pre- and post-operatively. The secondary aim is to compare patient-reported outcome after oncoplastic or traditional conservative surgery.

PATIENTS AND METHODS

We enrolled 647 patients who underwent traditional conservative surgery or oncoplastic surgery from January 2020 to December 2022. Only 232 women (35.9%) completed the BREAST-Q questionnaire on a web-based platform, at the preoperative phase and 3 months after treatment.

RESULTS

The average score of "Psychosocial well-being" and "Satisfaction with Breasts" 3 months after surgery showed a statistically significant improvement, while the average score for "Physical well-being: Chest" at 3 months showed a worsening compared to the baseline. "Sexual well-being" did not show statistically significant change. A significant difference between the post-operative outcome of oncoplastic surgery and traditional surgery was observed only for Physical well-being (better for traditional surgery).

CONCLUSIONS

The study showed significant improvement in patient-reported outcomes 3 months after the surgery, except for physical discomfort that increases especially after oncoplastic surgery. Furthermore, our data, as well as many others, point to the appropriateness of using OCS where there is an effective indication, while the perspective of patients cannot find significant superiority over TCS in any of the areas analyzed.

Healthcare costs of diabetic foot disease in Italy: estimates for event and state costs

OBJECTIVE

This study aimed to estimate healthcare costs of diabetic foot disease (DFD) in a large population-based cohort of people with type-2 diabetes (T2D) in the Tuscany region (Italy).

DATA SOURCES/STUDY SETTING

Administrative healthcare data of Tuscany region, with 2018 as the base year.

STUDY DESIGN

Retrospective study assessing a longitudinal cohort of patients with T2D.

DATA COLLECTION/EXTRACTION METHODS

Using administrative healthcare data, DFD were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes.

METHODS

We examined the annual healthcare costs of these clinical problems in patients with T2D between 2015 and 2018; moreover, we used a generalized linear model to estimate the total healthcare costs.

PRINCIPAL FINDINGS

Between 2015 and 2018, patients with T2D experiencing DFD showed significantly higher average direct costs than patients with T2D without DFD (p < 0.0001). Among patients with T2D experiencing DFD, those who experienced complications either in 2015-2017 and in 2018 incurred the highest incremental costs (incremental cost of € 16,702) followed by those with complications in 2018 only (incremental cost of € 9,536) and from 2015 to 2017 (incremental cost of € 800).

CONCLUSIONS

DFD significantly increase healthcare utilization and costs among patients with TD2. Healthcare costs of DFD among patients with T2D are associated with the timing and frequency of DFD. These findings should increase awareness among policymakers regarding resource reallocation toward preventive strategies among patients with T2D.

Including patient-reported measures in performance evaluation systems: Patient contribution in assessing and improving the healthcare systems

In healthcare, the introduction of quality standards and indicators to assess performance triggered the development of multidimensional Performance Management Systems (PMSs). The concept of performance in healthcare has recently evolved and broadened its scope. One of the current challenges of PMSs is measuring and integrating the patient perspective into traditional measures. In the regional healthcare system of Tuscany (Italy), a PMS has been implemented and used since 2005. The PMS counts on the systematic involvement of clinicians and managers. Furthermore, the PMS also includes patients' perspective. Moreover, Tuscany has recently implemented the first regional permanent Patient-Reported Outcome and Experience Measures (PROMs and PREMs) Observatory in Italy. This paper presents the results of an action research aimed at analysing the integration of patient-reported outcome and experience indicators into a consolidated PMS. The study describes the process of identifying and discussing of patient-reported indicators with practitioners and categorising findings into three domains: design of patient-reported indicators, integration process into the PMS, and goal of adoption of the patient-related indicators. The paper also describes facilitators, challenges, and lessons learnt with respect to organisational, methodological, cultural, and responsibility-linked factors. The study discusses the ability to agree on how to transform patient data, especially PROMs, into effective performance indicators. The integration of patient-reported indicators into the PMS poses two main challenges: one in terms of sustainability of the performance system itself, and another regarding the attribution of the responsibility for patient outcomes between care settings and providers. This paper provides initial insights on how the integration of patient-reported indicators can make PMSs more inclusive and focussed on the patient-centred perspective.

Exploring Cost-Effectiveness of the Comprehensive Geriatric Assessment in Geriatric Oncology: A Narrative Review

Simple Summary

The Comprehensive Geriatric Assessment is a multidimensional and multidisciplinary evaluation designed for elderly patients with the goal of structuring tailored care and follow-up. Despite the known benefits of this approach, the Comprehensive Geriatric Assessment is not universally applied to elderly cancer patients due to economic and practical barriers. This narrative review aims to investigate the cost-effectiveness of the Comprehensive Geriatric Assessment adopted in geriatric oncology. The results revealed a lack of research on the topic, but recurrent cost-saving effects of this approach in geriatric oncology settings were highlighted—suggesting a positive cost-effectiveness ratio. Further structured research with comprehensive economic evaluations is needed to confirm these findings.

Abstract

The Comprehensive Geriatric Assessment (CGA) and the corresponding geriatric interventions are beneficial for community-dwelling older persons in terms of reduced mortality, disability, institutionalisation and healthcare utilisation. However, the value of CGA in the management of older cancer patients both in terms of clinical outcomes and in cost-effectiveness remains to be fully established, and CGA is still far from being routinely implemented in geriatric oncology. This narrative review aims to analyse the available evidence on the cost-effectiveness of CGA adopted in geriatric oncology, identify the relevant parameters used in the literature and provide recommendations for future research. The review was conducted using the PubMed and Cochrane databases, covering published studies without selection by the publication year. The extracted data were categorised according to the study design, participants and measures of cost-effectiveness, and the results are summarised to state the levels of evidence. The review conforms to the SANRA guidelines for quality assessment. Twenty-nine studies out of the thirty-seven assessed for eligibility met the inclusion criteria. Although there is a large heterogeneity, the overall evidence is consistent with the measurable benefits of CGA in terms of reducing the in-hospital length of stay and treatment toxicity, leaning toward a positive cost-effectiveness of the interventions and supporting CGA implementation in geriatric oncology clinical practice. More research employing full economic evaluations is needed to confirm this evidence and should focus on CGA implications both from patient-centred and healthcare system perspectives.

Integrating mammography screening programmes into specialist breast centres in Italy: insights from a national survey of Senonetwork breast centres

Background

Despite recommendations, mammography screening is often insufficiently integrated into specialist breast centres. A national, cross-sectional, voluntary, online survey on this issue was carried out among the Italian breast centres associated with Senonetwork, the Italian network of breast cancer services.

Methods

A 73-item questionnaire was created, pre-tested and piloted. Centres integrating and not integrating a screening programme were compared using the unified theory of acceptance and use of technology (UTAUT) model. Centres’ clustering was performed using the Gower’s distance metric. Groups and clusters were compared with the equality-of-means test.

Results

The response rate was 82/128 (65%). Overall, 84% (69/82) breast centres reported a collaboration with a screening programme in performing and/or reading mammograms and in the diagnostic work-up of women with abnormal screening results. The same proportion was observed among those centres responding to all questions (62/74). Performance expectancies (or the perceived usefulness of integration in terms of clinical quality, patient convenience, ease of job, and professional growth), satisfaction and motivation were higher in those centres collaborating with the screening programme. Effort expectancy indicators (or the degree to which the respondents believe that the integration is easy to implement) and those concerning the existence of facilitating conditions were lower both in centres collaborating and not collaborating with the screening programme. Among the former, six clusters of centres, distributed from ‘no integration’ to ‘high’, were identified. In cluster analysis, the highest level of integration was associated with higher agreement that integration eases the job, offers better opportunities for professional growth, and makes the working environment more satisfactory. The least integrated cluster assigned the lowest score to the statement that local health authority made available the resources needed.

Conclusions

While confirming the positive effects of integrating screening programmes into breast centres, this survey has brought to light specific difficulties that must be faced. The results provide insights into the importance of integration focusing on the perspectives of professional career and motivation. The deficiency of facilitating conditions to integration is modifiable. Screening professionals’ societies may have a role as initiators of the integration. Other supporting actions may be included in health laws at the national and regional level.

The Role of Recipient Characteristics in Health Video Communication Outcomes: Scoping Review

BACKGROUND

The importance of effective communication during public health emergencies has been highlighted by the World Health Organization, and it has published guidelines for effective communication in such situations. With video being a popular medium, video communication has been a growing area of study over the past decades and is increasingly used across different sectors and disciplines, including health. Health-related video communication gained momentum during the SARS-CoV-2 pandemic, and video was among the most frequently used modes of communication worldwide. However, although much research has been done regarding different characteristics of video content (the message) and its delivery (the messenger), there is a lack of knowledge about the role played by the characteristics of the recipients for the creation of effective communication.

OBJECTIVE

The aim of this review is to identify how health video communication outcomes are shaped by recipient characteristics, as such characteristics might affect the effectiveness of communication. The main research question of the study is as follows: do the characteristics of the recipients of health videos affect the outcomes of the communication?

METHODS

A scoping review describing the existing knowledge within the field was conducted. We searched for literature in 3 databases (PubMed, Scopus, and Embase) and defined eligibility criteria based on the relevance to the research question. Recipient characteristics and health video communication outcomes were identified and classified.

RESULTS

Of the 1040 documents initially identified, 128 (12.31%) met the criteria for full-text assessment, and 39 (3.75%) met the inclusion criteria. The included studies reported 56 recipient characteristics and 42 communication outcomes. The reported associations between characteristics and outcomes were identified, and the potential research opportunities were discussed. Contributions were made to theory development by amending the existing framework of the Integrated-Change model, which is an integrated model of motivational and behavioral change.

CONCLUSIONS

Although several recipient characteristics and health video communication outcomes were identified, there is a lack of robust empirical evidence on the association between them. Further research is needed to understand how the preceding characteristics of the recipients might affect the various outcomes of health video communication.

Systematic and continuous collection of patient-reported outcomes and experience in women with cancer undergoing mastectomy and immediate breast reconstruction: a study protocol for the Tuscany Region (Italy)

INTRODUCTION

Monitoring how patients feel and what they experience during the care process gives health professionals data to improve the quality of care, and gives health systems information to better design and implement care pathways. To gain new insights about specific gaps and/or strengths in breast cancer care, we measure patient-reported outcomes (PROs) and patient-reported experiences (PREs) for women receiving immediate breast reconstruction (iBR).

METHODS AND ANALYSIS

Prospective, multicentre, cohort study with continuous and systematic web-based data collection from women diagnosed with breast cancer, who have an indication for iBR after mastectomy treated at any Breast Unit (BU) in Tuscany Region (Italy). Patients are classified into one of two groups under conditions of routine clinical practice, based on the type of iBR planned (implant and autologous reconstruction). Patient-reported information are obtained prior to and after surgery (at 3-month and 12-month follow-up). We estimate that there are around 700 annual eligible patients.Descriptive analyses are used to assess trends in PROs over time and differences between types of iBR in PROs and PREs. Additionally, econometric models are used to analyse patient and BU characteristics associated with outcomes and experiences. PREs are evaluated to assess aspects of integrated care along the care pathway.

ETHICS AND DISSEMINATION

The study has been reviewed and obtained a nihil obstat from the Tuscan Ethics Committees of the three Area Vasta in 2017. Dissemination of results will be via periodic report, journal articles and conference presentations.

Proximity and waiting times in choice models for outpatient cardiological visits in Italy

We apply mixed logit regression to investigate patients' choice of non-emergency outpatient cardiovascular specialists in Tuscany, Italy. We focused on the effects of travel time and waiting time. Results reveal that patients prefer clinics nearby and with shorter waiting times. Differences in patient choice depend on age and socioeconomic conditions, thus confirming equity concerns in the access of non-acute services. Our results could be used to optimize the allocation of resources, reduce inequities and increase the efficiency and responsiveness of outpatient systems considering patient preferences.

Critical review of economic evaluation studies of interventions promoting low-fat diets

Various national and local policies encouraging healthy eating have recently been proposed. The present review aims to summarize and critically assess nutrition-economic evaluation studies of direct (e.g., diet counseling) and indirect (e.g., food labeling) interventions aimed at improving dietary habits. A systematic literature review was performed by searching 5 databases (PubMed, Ovid Medline, EconLit, Agricola, and Embase) using a combination of diet-related (fat, diet, intake, nutrition) and economics-related (cost-effectiveness, cost-benefit, cost-utility, health economics, economic evaluation) key words. The search yielded 36 studies that varied in target population, study design, economic evaluation method, and health/economic outcome. In general, all provide limited experimental evidence and adopt the framework of economic evaluations in healthcare. Certain important aspects were not well considered: 1) the non-health-related effects of nutrition interventions on well-being; 2) the private nature of food expenditures; 3) the distributional effects on food expenditures across socioeconomic groups; and 4) the general economic implications (e.g., agrofoods, import/export) of such interventions. Overall, the methodology for the economic evaluation of nutrition interventions requires substantial improvement.

Aphasia induced by gliomas growing in the ventrolateral frontal region: assessment with diffusion MR tractography, functional MR imaging and neuropsychology

INTRODUCTION

Lesions in the ventrolateral region of the dominant frontal lobe have been historically associated with aphasia. Recent imaging results suggest that frontal language regions extend beyond classically defined Broca's area to include the ventral precentral gyrus (VPCG) and the arcuate fasciculus (AF). Frontal gliomas offer a unique opportunity to identify structures that are essential for speech production. The aim of this prospective study was to investigate the correlation between language deficits and lesion location in patients with gliomas.

METHODS

Nineteen patients with glioma and 10 healthy subjects were evaluated with diffusion tensor imaging magnetic resonance (MR) tractography, functional MR (verb generation task) and the Aachener Aphasie Test. Patients were divided into two groups according to lesion location with respect to the ventral precentral sulcus: (i) anterior (n=8) with glioma growing in the inferior frontal gyrus (IFG) and underlying white matter; (ii) posterior (n=11) with glioma growing in the VPCG and underlying white matter. Virtual dissection of the AF, frontal intralobar tract, uncinate fasciculus (UF) and inferior frontal occipital fasciculus (IFOF) was performed with a deterministic approach.

RESULTS

Seven posterior patients showed aphasia classified as conduction (4), Broca (1), transcortical motor (1) and an isolated deficit of semantic fluency; one anterior patient had transcortical mixed aphasia. All posterior patients had invasion of the VPCG, however only patients with aphasia had also lesion extension to the AF as demonstrated by tractography dissections. All patients with language deficits had high grade glioma. Groups did not differ regarding tumour volume. A functional pars opercularis was identified with functional MR imaging (fMRI) in 17 patients.

CONCLUSIONS

Gliomas growing in the left VPCG are much more likely to cause speech deficits than gliomas infiltrating the IFG, including Broca's area. Lesion extension to the AF connecting frontal to parietal and temporal regions is an important mechanism for the appearance of aphasia.

DIAL: a web server for the pairwise alignment of two RNA three-dimensional structures using nucleotide, dihedral angle and base-pairing similarities

DIAL (dihedral alignment) is a web server that provides public access to a new dynamic programming algorithm for pairwise 3D structural alignment of RNA. DIAL achieves quadratic time by performing an alignment that accounts for (i) pseudo-dihedral and/or dihedral angle similarity, (ii) nucleotide sequence similarity and (iii) nucleotide base-pairing similarity.

DIAL provides access to three alignment algorithms: global (Needleman–Wunsch), local (Smith–Waterman) and semiglobal (modified to yield motif search). Suboptimal alignments are optionally returned, and also Boltzmann pair probabilities Pr(a_i,b_j) for aligned positions a_i , b_j from the optimal alignment. If a non-zero suboptimal alignment score ratio is entered, then the semiglobal alignment algorithm may be used to detect structurally similar occurrences of a user-specified 3D motif. The query motif may be contiguous in the linear chain or fragmented in a number of noncontiguous regions.

The DIAL web server provides graphical output which allows the user to view, rotate and enlarge the 3D superposition for the optimal (and suboptimal) alignment of query to target. Although graphical output is available for all three algorithms, the semiglobal motif search may be of most interest in attempts to identify RNA motifs. DIAL is available at http://bioinformatics.bc.edu/clotelab/DIAL.

DiANNA 1.1: an extension of the DiANNA web server for ternary cysteine classification

DiANNA is a recent state-of-the-art artificial neural network and web server, which determines the cysteine oxidation state and disulfide connectivity of a protein, given only its amino acid sequence. Version 1.0 of DiANNA uses a feed-forward neural network to determine which cysteines are involved in a disulfide bond, and employs a novel architecture neural network to predict which half-cystines are covalently bound to which other half-cystines. In version 1.1 of DiANNA, described here, we extend functionality by applying a support vector machine with spectrum kernel for the cysteine classification problem-to determine whether a cysteine is reduced (free in sulfhydryl state), half-cystine (involved in a disulfide bond) or bound to a metallic ligand. In the latter case, DiANNA predicts the ligand among iron, zinc, cadmium and carbon. Available at: http://bioinformatics.bc.edu/clotelab/DiANNA/.

BTW: a web server for Boltzmann time warping of gene expression time series

Dynamic time warping (DTW) is a well-known quadratic time algorithm to determine the smallest distance and optimal alignment between two numerical sequences, possibly of different length. Originally developed for speech recognition, this method has been used in data mining, medicine and bioinformatics. For gene expression time series data, time warping distance is arguably a more flexible tool to determine genes having similar temporal expression, hence possibly related biological function, than either Euclidean distance or correlation coefficient—especially since time warping accommodates sequences of different length. The BTW web server allows a user to upload two tab-separated text files A,B of gene expression data, each possibly having a different number of time intervals of different durations. BTW then computes time warping distance between each gene of A with each gene of B, using a recently developed symmetric algorithm which additionally computes the Boltzmann partition function and outputs Boltzmann pair probabilities. The Boltzmann pair probabilities, not available with any other existent software, suggest possible biological significance of certain positions in an optimal time warping alignment. Availability: .

DiANNA: a web server for disulfide connectivity prediction

Correctly predicting the disulfide bond topology in a protein is of crucial importance for the understanding of protein function and can be of great help for tertiary prediction methods. The web server http://clavius.bc.edu/~clotelab/DiANNA/ outputs the disulfide connectivity prediction given input of a protein sequence. The following procedure is performed. First, PSIPRED is run to predict the protein's secondary structure, then PSIBLAST is run against the non-redundant SwissProt to obtain a multiple alignment of the input sequence. The predicted secondary structure and the profile arising from this alignment are used in the training phase of our neural network. Next, cysteine oxidation state is predicted, then each pair of cysteines in the protein sequence is assigned a likelihood of forming a disulfide bond--this is performed by means of a novel architecture (diresidue neural network). Finally, Rothberg's implementation of Gabow's maximum weighted matching algorithm is applied to diresidue neural network scores in order to produce the final connectivity prediction. Our novel neural network-based approach achieves results that are comparable and in some cases better than the current state-of-the-art methods.

Disulfide connectivity prediction using secondary structure information and diresidue frequencies

MOTIVATION

We describe a stand-alone algorithm to predict disulfide bond partners in a protein given only the amino acid sequence, using a novel neural network architecture (the diresidue neural network), and given input of symmetric flanking regions of N-terminus and C-terminus half-cystines augmented with residue secondary structure (helix, coil, sheet) as well as evolutionary information. The approach is motivated by the observation of a bias in the secondary structure preferences of free cysteines and half-cystines, and by promising preliminary results we obtained using diresidue position-specific scoring matrices.

RESULTS

As calibrated by receiver operating characteristic curves from 4-fold cross-validation, our conditioning on secondary structure allows our novel diresidue neural network to perform as well as, and in some cases better than, the current state-of-the-art method. A slight drop in performance is seen when secondary structure is predicted rather than being derived from three-dimensional protein structures.

Protein surface similarities: a survey of methods to describe and compare protein surfaces

Many methods have been developed to analyse protein sequences and structures, although less work has been undertaken describing and comparing protein surfaces. Evolution can lead sequences to diverge or structures to change topology; nevertheless, surface determinants that are essential to protein function itself may be mantained. Moreover, different molecules could converge to similar functions by gaining specific surface determinants. In such cases, sequence or structure comparisons are likely to be inadequate in describing or identifying protein functions and evolutionary relationships among proteins. Surface analysis can identify function determinants that are independent of sequence or secondary structure and can therefore be a powerful tool to highlight cases of possible convergent or divergent evolution. This kind of approach can be useful for a better understanding of protein molecular and biochemical mechanisms of catalysis or interaction with a ligand, which are usually surface dependent. Protein surface comparison, when compared to sequence or structure comparison methods, is a hard computational challenge and evaluated methods allowing the comparison of protein surfaces are difficult to find. In this review, we will survey the current knowledge about protein surface similarity and the techniques to detect it.

Three-dimensional view of the surface motif associated with the P-loop structure: cis and trans cases of convergent evolution

Here we identify the determinants of the nucleotide-binding ability associated with the P-loop-containing proteins, inferring their functional importance from their structural convergence to a unique three- dimensional (3D) motif. (1) A new surface 3D pattern is identified for the P-loop nucleotide-binding region, which is more selective than the corresponding sequence pattern; (2) the signature displays one residue that we propose is the determinant for the guanine-binding ability (the residues aligned to ras D119; this residue is known to be important only in the G-proteins, we extend the prediction to all the other P-loop- containing proteins); and (3) two cases of convergent evolution at the molecular level are highlighted in the analysis of the active site: the positive charge aligned to ras K117 and the arginine residues aligned to the GAP arginine finger. The analysis of the residues conserved on protein surfaces allows one to identify new functional or evolutionary relationships among protein structures that would not be detectable by conventional sequence or structure comparison methods.