1,721,612 research outputs found
Correction to: Safety of laparoscopic compared to open right hepatectomy after portal vein occlusion: results from a multicenter study (Surgical Endoscopy, (2025), 39, 3, (1839-1847), 10.1007/s00464-025-11532-8)
No full textThe original online version of this article was revised to correct the presentation of the name of coauthor Nadia Russolillo, and to correct the affiliation information for corresponding author Serena Langella. The original article has been corrected
On the use of Structural Equation Models and PLS Path Modeling to build composite indicators
No full textNowadays there is a pre-eminent need to measure very complex phenomena like poverty, progress, well-being, etc. As is well known, the main feature of a composite indicator is that it summarizes complex and multidimensional issues. Thanks to its features, Structural Equation Modeling seems to be a useful tool for building systems of composite indicators. Among the several methods that have been developed to estimate Structural Equation Models we focus on the PLS Path Modeling approach (PLS-PM), because of the key role that estimation of the latent variables (i.e. the composite indicators) plays in the estimation process. In this work, first we present Structural Equation Models and PLS-PM. Then we provide a suite of statistical methodologies for handling categorical indicators in PLS-PM. In particular, in order to take categorical indicators into account, we propose to use a modified version of the PLS-PM algorithm recently presented by Russolillo [2009]. This new approach provides a quantification of the categorical indicators in such a way that the weight of each quantified indicator is coherent with the explicative ability of the corresponding categorical indicator. To conclude, an application involving data taken from a paper by Russet [1964] will be presented.PLS Path Modeling,Categorical Indicators,Structural Equation Modeling,Composite Indicators
Tackling Non-Communicable Diseases by a forecasting model for Critical Illness Cover
No full textNon-communicable diseases are the most frequent causes of death in most countries in the Americas, the Eastern Mediterranean, Europe, South-East Asia, and the Western Pacific. In the African Region, there are still more deaths from infectious diseases than NCDs. WHO projections show that NCDs will be responsible for a significantly increased total number of deaths in the next decade (WHO, 2014). In this context, the market of illness insurance is strongly being developed, allowing policyholders to reduce the financial impact of diseases. Indeed, critical illness insurance typically provides a payment of a lump sum in the event of the person insured suffering a condition covered under the policy. In other words, the insured receives a fixed sum on the diagnosis of a specified list of critical illnesses. The contract terms may also be structured to pay out regular income cash-flows on the policyholder. In general, since the policy face amount has to be paid on diagnosis, the incidence rates or diagnosis rates have to be accurately estimated. The research is here developed around the following focal and original points: • the estimation of the diagnosis rates by means of an analysis by cause of death for obtaining cause-specific diagnosis rates: in particular, the author modelі the probability of death by cause as a proxy of the estimate of the diagnosis rates; • the cause-specific death rates are modelled by a stratified stochastic model for avoiding the durable problem in literature of the dependence among different causes of death; • a fair valuation framework is adopted for pricing a specific product of critical illness insurance. The analysis is completed by empirical finding
MID1 mutations in patients with X-linked Opitz G/BBB syndrome
No full textMutations in the MID1 gene are responsible for the X-linked form of Opitz G/BBB syndrome (OS), a disorder that affects the development of midline structures. OS is characterized by hypertelorism, hypospadias, laryngo-tracheo-esophageal (LTE) abnormalities, and additional midline defects. Cardiac, anal, and neurological defects are also present. The expressivity of OS is highly variable, even within the same family. We reviewed all the MID1 mutations reported so far, in both familial and sporadic cases. The mutations are scattered along the entire length of the gene and consist of missense and nonsense mutations, insertions and deletions, either in-frame or causing frameshifts, and deletions of either single exons or the entire MID1 coding region. The variety of described mutations and the lack of a strict genotype-phenotype correlation confirm the previous suggestion of the OS phenotype being caused by a loss-of-function mechanism. However, although a specific mutation cannot entirely account for the observed phenotype, we observed preferential association between some types of mutation and specific clinical manifestations, e.g., brain anatomical defects and truncating mutations. This may suggest that the pathogenetic mechanism underlying the OS phenotype is more complex and may vary among the affected organs
ALCOLIZZAZIONE ASSOCIATA ALLA LEGATURA PORTALE: UNA TECNICA EFFICACE PER INCREMENTARE LA RIGENERAZIONE EPATICA
No full textINTRODUZIONE E OBIETTIVO: L’occlusione della vena porta mediante legatura (PVL) o embolizzazione (PVE) è utilizzata nella pratica clinica per favorire la rigenerazione epatica nei pazienti con volume di fegato residuo (FLRV) all’intervento programmato inadeguato. Alcuni Autori hanno descritto un più elevato tasso di rigenerazione epatica nei pazienti sottoposti a PVE rispetto alla PVL, come conseguenza della formazione in questi ultimi di collaterali porto-portali tra il segmento 4 e i segmenti 5 e 8. L’obiettivo dello studio era di paragonare il tasso di rigenerazione epatica dopo legatura portale con (gruppo Alc+) e senza (gruppo Alc-) la simultanea iniezione intra-portale di alcool.
PAZIENTI E METODI: 42 pazienti affetti da metastasi colorettali sottoposti tra 01/2004 e 06/2014 a PVL preoperatoria sono stati analizzati. A partire dal 09/2011 la legatura portale destra è stata preceduta dall’iniezione intraportale di alcool puro. IL FLRV è stato calcolato sulla base degli esami TC. Due radiologi hanno rivisto le immagini delle TC post-PVL al fine di identificare la presenza di cavernomi e ricanalizzazioni del flusso nel ramo portale occluso. La rigenerazione epatica è stata valutata in termini di Incremento Volumetrico (VI) calcolato con la seguente formula: [(FLRVpost PVL% – FLRVpre PVL%)/FLRVpre PVL%].
RISULTATI: I pazienti del gruppo Alc+ (n=23) e Alc- (n=19) erano simili in termini di età, sesso, diabete, FLRV pre-PVL e per la somministrazione di chemioterapia. Il tasso di ricanalizzazione portale (63.1% vs. 4.3%, p<0.001) e la presenza di cavernomi (36.8% vs. 8.7%, p=0.055) dopo PVL erano significativamente superiori nei pazienti del gruppo Alc-. Il FLRV post-PVL (43.3±14.3% vs. 34.6±6.4%, p=0.013) e l’incremento volumetrico VI (0.44±0.24 vs. 0.28±0.20, p=0.029) erano significativamente superiori nel gruppo Alc+. All’analisi univariata il sesso maschile (0.23±024 vs.0.40±0.19, p=0.005) e la PVL senza alcolizzazione (0.35±0.24 vs. 0.26±0.20, p=0.035) sono risultati negativamente correlati con il valore di VI. L’analisi multivariata ha mostrato che il sesso maschile (B=−0.149, p=0.035) e l’iniezione intraportale di alcool (B=0.143 p=0.041) correlavano significativamente con il valore di VI [F(1,40)=5.200, p=0.010].
CONCLUSIONI: L’iniezione di alcool prima della legatura portale incrementa significativamente la rigenerazione del FLRV, riducendo la ricanalizzazione del flusso nel ramo portale occlusoBACKGROUND AND AIM: Portal vein occlusion by ligation (PVL) or embolization (PVE) is routinely performed to increase inadequate future liver remnant volume (FLRV) . The higher liver regeneration rate observed after PVE than after PVL may be due to the formation in the latter of intrahepatic porto-portal collaterals between the portal branches of segment 4 and the branches of the adjacent right segments 5 and 8. The aim of the study was to compare liver regeneration rate following portal vein ligation (PVL) with (Alc+) and without (Alc-) simultaneous intraportal alcohol injection
METHODS: Forty-two patients with colorectal liver metastases who underwent PVL between January 2004 and June 2014 were analyzed. Beginning in September 2011, absolute alcohol was injected prior to right PVL. Future liver remnant volume (FLRV) was assessed by CT-scan. CT-scans were reviewed to assess recanalization and/or cavernous transformation of the occluded portal vein. Liver regeneration was assessed as Volumetric Increase (VI) [(FLRVpost% – FLRVpre%)/FLRVpre%].
RESULTS: The Alc+ (n=23) and Alc- (n=19) groups were similar in age, sex, diabetes, pre-PVL FLRV and administration of chemotherapy. The rate of recanalization of the occluded portal vein was significantly higher (63.1% vs. 4.3%, p<0.001) and the rate of cavernous transformation higher (36.8% vs. 8.7%, p=0.055) in the Alc- than in the Alc+ group. Post-PVL FLRV (43.3±14.3% vs. 34.6±6.4%, p=0.013) and VI (0.44±0.24 vs. 0.28±0.20, p=0.029) were significantly higher in the Alc+ group. Univariate analysis showed that male sex (0.23±024 vs.0.40±0.19, p=0.005) and PVL without alcohol injection (0.35±0.24 vs. 0.26±0.20, p=0.035) were negatively correlated with VI. Multiple regression analysis showed that male sex (B=−0.149, p=0.035) and alcohol injection (B=0.143 p=0.041) significantly predicted VI [F(1,40)=5.200, p=0.010].
CONCLUSIONS: Alcohol injection prior to PVL significantly increased regeneration rate of the future liver remnant, reducing recanalization of the occluded portal vein
The Future Human Lifespan: A study on Italian Population
No full textIn the latter part of the 20th century, continued improvements in living standards, health behaviors,
and medical care reduced mortality and produced amazing advances in life expectancy.
These trends, followed by all industrial nations, decidedly affect the financial position of an insurance
company, interested in the construction of updated life tables. The approach to this problem
is faced in this paper by using the Lee-Carter methodology. In particular, in the present work,
we are interested in modeling and forecasting mortality and life expectancy on a period basis
through the use of a stochastic forecasting method which uses time-series models to make
long-term forecasts
Multiple mortality modeling in Poisson Lee-Carter framework
No full textThe academic literature in longevity field has recently focused on models for detecting multiple population trends (D'Amato et al., 2012b; Njenga and Sherris, 2011; Russolillo et al., 2011, etc.). In particular, increasing interest has been shown about "related" population dynamics or "parent" populations characterized by similar socioeconomic conditions and eventually also by geographical proximity. These studies suggest dependence across multiple populations and common long-run relationships between countries (for instance, see Lazar et al., 2009). In order to investigate cross-country longevity common trends, we adopt a multiple population approach. The algorithm we propose retains the parametric structure of the Lee-Carter model, extending the basic framework to include some cross-dependence in the error term. As far as time dependence is concerned, we allow for all idiosyncratic components (both in the common stochastic trend and in the error term) to follow a linear process, thus considering a highly flexible specification for the serial dependence structure of our data. We also relax the assumption of normality, which is typical of early studies on mortality (Lee and Carter, 1992) and on factor models (see e.g., the textbook by Anderson, 1984). The empirical results show that the multiple Lee-Carter approach works well in the presence of dependence
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