Nighttime features derived from topic models for classification of patients with COPD

Nighttime symptoms are important indicators of impairment for many diseases and particularly for respiratory diseases such as chronic obstructive pulmonary disease (COPD). The use of wearable sensors to assess sleep in COPD has mainly been limited to the monitoring of limb motions or the duration and continuity of sleep. In this paper we present an approach to concisely describe sleep patterns in subjects with and without COPD. The methodology converts multimodal sleep data into a text representation and uses topic modeling to identify patterns across the dataset composed of more than 6000 assessed nights. This approach enables the discovery of higher level features resembling unique sleep characteristics that are then used to discriminate between healthy subjects and those with COPD and to evaluate patients' disease severity and dyspnea level. Compared to standard features, the discovered latent structures in nighttime data seem to capture important aspects of subjects sleeping behavior related to the effects of COPD and dyspnea.

Synchrotron-based Mössbauer spectroscopy characterization of sublimated spin crossover molecules

The spin crossover (SCO) efficiency of [⁵⁷Fe(bpz)₂(phen)] (where bpz = bis(pyrazol-1-yl)borohydride and phen = 9,10-phenantroline) molecules deposited on gold substrates was investigated by means of synchrotron Mössbauer spectroscopy. The spin transition was driven thermally, or light induced via the LIESST (light induced excited spin-state trapping) effect. Both sets of measurements show that, once deposited on a gold substrate, the efficiency of the SCO mechanism is modified with respect to molecules in the bulk phase. A correlation in the distribution of hyperfine parameters in the sublimated films, not evidenced so far in the bulk phase, is reported. This translates into geometrical distortions of the first coordination sphere of the iron atom that seem to correlate with the decreased spin conversion. The work reported clearly shows the potentiality of synchrotron Mössbauer spectroscopy for the characterization of nanostructured Fe-based SCO systems, thus resulting as a key tool in view of their applications in innovative nanoscale devices.

Remote timed up and go evaluation from activities of daily living reveals changing mobility after surgery

BACKGROUND

Mobility impairment is common in older adults and negatively influences the quality of life. Mobility level may change rapidly following surgery or hospitalization in the elderly. The timed up and go (TUG) is a simple, frequently used clinical test for functional mobility; however, TUG requires supervision from a trained clinician, resulting in infrequent assessments. Additionally, assessment by TUG in clinic settings may not be completely representative of the individual's mobility in their home environment.

OBJECTIVE

In this paper, we introduce a method to estimate TUG from activities detected in free-living, enabling continuous remote mobility monitoring without expert supervision. The method is used to monitor changes in mobility following total hip arthroplasty (THA).

METHODS

Community-living elderly (n  =  239, 65-91 years) performed a standardized TUG in a laboratory and wore a wearable pendant device that recorded accelerometer and barometric sensor data for at least three days. Activities of daily living (ADLs), including walks and sit-to-stand transitions, and their related mobility features were extracted and used to develop a regularized linear model for remote TUG test estimation. Changes in the remote TUG were evaluated in orthopaedic patients (n  =  15, 55-75 years), during 12-weeks period following THA.

MAIN RESULTS

In leave-one-out-cross-validation (LOOCV), a strong correlation (ρ  =  0.70) was observed between the new remote TUG and standardized TUG times. Test-retest reliability of 3-days estimates was high (ICC  =  0.94). Compared to week 2 post-THA, remote TUG was significantly improved at week 6 (11.7  ±  3.9 s versus 8.0  ±  1.8 s, p   <  0.001), with no further change at 12-weeks (8.1  ±  3.9 s, p   =  0.37).

SIGNIFICANCE

Remote TUG can be estimated in older adults using 3-days of ADLs data recorded using a wearable pendant. Remote TUG has discriminatory potential for identifying frail elderly and may provide a convenient way to monitor changes in mobility in unsupervised settings.

Psychosocial functioning, self-image, and quality of life in children and adolescents with neurofibromatosis type 1

BACKGROUND

Neurofibromatosis type 1 (NF1) is a genetic disorder associated with neurocutaneus manifestations, as well as attention and learning problems. The aim of this study was to examine the psychosocial functioning, quality of life, and self-image of children with NF1.

METHOD

Two hundred forty participants were recruited, comprising 60 children and adolescents with NF1, 60 parents of children with NF1, 60 children and adolescents without NF1, and 60 parents of children without NF1. The children/adolescents completed the Self-administered Psychiatric Scales test for Children and Adolescents and the human figure drawing test, whereas parents completed the Child Behavior Checklist. Both children and parents completed the Pediatric Quality of Life Inventory.

RESULTS

Compared to healthy subjects, individuals with NF1 reported anxiety problems, poorer quality of life, and greater distortions in terms of self-image. When compared to healthy participants' parents, the parents of NF1 participants reported having more concerns about the quality of life, sociality, school performance, and attention span of their children.

CONCLUSIONS

Results show that the psychological functioning, behavior, self-image, and quality of life of children and adolescents with NF1 are compromised. Health services should take into account the psychosocial difficulties associated with NF1 and design rehabilitation programs aimed at increasing NF1 children's interpersonal skills, improving their social life and quality of life, and promoting more adaptive behaviors. In addition, health care interventions should also involve the parents of children with NF1.

Study of manganese binding to the ferroxidase centre of human H-type ferritin

Ferritins are ubiquitous and conserved proteins endowed with enzymatic ferroxidase activity, that oxidize Fe(II) ions at the dimetal ferroxidase centre to form a mineralized Fe(III) oxide core deposited within the apo-protein shell. Herein, the in vitro formation of a heterodimetal cofactor constituted by Fe and Mn ions has been investigated in human H ferritin (hHFt). Namely, Mn and Fe binding at the hHFt ferroxidase centre and its effects on Fe(II) oxidation have been investigated by UV-Vis ferroxidation kinetics, fluorimetric titrations, multifrequency EPR, and preliminary Mössbauer spectroscopy. Our results show that in hHFt, both Fe(II) and Mn(II) bind the ferroxidase centre forming a Fe-Mn cofactor. Moreover, molecular oxygen seems to favour Mn(II) binding and increases the ferroxidation activity of the Mn-loaded protein. The data suggest that Mn influences the Fe binding and the efficiency of the ferroxidation reaction. The higher efficiency of the Mn-Fe heterometallic centre may have a physiological relevance in specific cell types (i.e. glia cells), where the concentration of Mn is the same order of magnitude as iron.

Fe-Doping-Induced Magnetism in Nano-Hydroxyapatites

Doping of biocompatible nanomaterials with magnetic phases is currently one of the most promising strategies for the development of advanced magnetic biomaterials. However, especially in the case of iron-doped magnetic hydroxyapatites, it is not clear if the magnetic features come merely from the magnetic phases/ions used as dopants or from complex mechanisms involving interactions at the nanoscale. Here, we report an extensive chemical-physical and magnetic investigation of three hydroxyapatite nanocrystals doped with different iron species and containing small or no amounts of maghemite as a secondary phase. The association of several investigation techniques such as X-ray absorption spectroscopy, Mössbauer, magnetometry, and TEM allowed us to determine that the unusual magnetic properties of Fe^2+/3+-doped hydroxyapatites (FeHA) occur by a synergy of two different phenomena: i.e., (i) interacting superparamagnetism due to the interplay between iron-doped apatite and iron oxide nanoparticles as well as to the occurrence of dipolar interactions and (ii) interacting paramagnetism due to Fe³⁺ ions present in the superficial hydrated layer of the apatite nanophase and, to a lesser extent, paramagnetism due to isolated Fe³⁺ ions in the apatite lattice. We also show that a major player in the activation of the above phenomena is the oxidation of Fe²⁺ into Fe³⁺, as induced by the synthesis process, and their consequent specific positioning in the FeHA structure.

Physical activity patterns and clusters in 1001 patients with COPD

We described physical activity measures and hourly patterns in patients with chronic obstructive pulmonary disease (COPD) after stratification for generic and COPD-specific characteristics and, based on multiple physical activity measures, we identified clusters of patients. In total, 1001 patients with COPD (65% men; age, 67 years; forced expiratory volume in the first second [FEV₁], 49% predicted) were studied cross-sectionally. Demographics, anthropometrics, lung function and clinical data were assessed. Daily physical activity measures and hourly patterns were analysed based on data from a multisensor armband. Principal component analysis (PCA) and cluster analysis were applied to physical activity measures to identify clusters. Age, body mass index (BMI), dyspnoea grade and ADO index (including age, dyspnoea and airflow obstruction) were associated with physical activity measures and hourly patterns. Five clusters were identified based on three PCA components, which accounted for 60% of variance of the data. Importantly, couch potatoes (i.e. the most inactive cluster) were characterised by higher BMI, lower FEV₁, worse dyspnoea and higher ADO index compared to other clusters (p < 0.05 for all). Daily physical activity measures and hourly patterns are heterogeneous in COPD. Clusters of patients were identified solely based on physical activity data. These findings may be useful to develop interventions aiming to promote physical activity in COPD.

Analysis of nocturnal actigraphic sleep measures in patients with COPD and their association with daytime physical activity

BACKGROUND

Sleep disturbances are common in patients with chronic obstructive pulmonary disease (COPD) with a considerable negative impact on their quality of life. However, factors associated with measures of sleep in daily life have not been investigated before nor has the association between sleep and the ability to engage in physical activity on a day-to-day basis been studied.

AIMS

To provide insight into the relationship between actigraphic sleep measures and disease severity, exertional dyspnoea, gender and parts of the week; and to investigate the association between sleep measures and next day physical activity.

METHODS

Data were analysed from 932 patients with COPD (66% male, 66.4±8.3 years, FEV₁% predicted=50.8±20.5). Participants had sleep and physical activity continuously monitored using a multisensor activity monitor for a median of 6 days. Linear mixed effects models were applied to investigate the factors associated with sleep impairment and the association between nocturnal sleep and patients' subsequent daytime physical activity.

RESULTS

Actigraphic estimates of sleep impairment were greater in patients with worse airflow limitation and worse exertional dyspnoea. Patients with better sleep measures (ie, non-fragmented sleep, sleeping bouts ≥225 min, sleep efficiency ≥91% and time spent awake after sleep onset <57 min) spent significantly more time in light (p<0.01) and moderate-to-vigorous physical activity (p<0.01).

CONCLUSIONS

There is a relationship between measures of sleep in patients with COPD and the amount of activity they undertake during the waking day. Identifying groups with specific sleep characteristics may be useful information when designing physical activity-enhancing interventions.

Child Abuse and Neglect and its Psycho-Physical and Social Consequences: A Review of the Literature

Child maltreatment is a complex life experience occurs when a parent or caregiver does an intentional or potential damage to a child, including acts of commission and omission. Child abuse is not an uncommon event, but it is not always recognized. Identifying the real number of maltreated children is a challenge because of the large variability in reported prevalence data across studies. Unfortunately, in the United States, it affects 1 in 8 children, by the age of 18 years, annually. Paediatricians may encounter a variety of forms of maltreatment such as neglect, emotional, physical and sexual abuse. These aspects should be recognised, examined and evaluated by employing a systematic approach and focusing on basic needs of children that may not be met. Child maltreatment is a global problem with serious life-long physical and psychological or psychiatric outcomes. It is associated with important economic and social costs (such as physical and mental health, productivity losses, child welfare, criminal justice and special education costs) due to its high prevalence and its long-term and short-term consequences. In the United States, the average cost of nonfatal maltreatment is $210,012 per children and the cost of fatal maltreatment is $1,272,900. General Practitioners are quite prepared to face the problem of child maltreatment: since they have the opportunity to meet several members of the same family, they can detect stressors that put children at risk of maltreatment. All health professionals have the responsibility to protect children from abuse and neglect.

Field effects on spontaneous magnetization reversal of bulk BiFe0.5Mn0.5O3, an effective strategy for the study of magnetic disordered systems

We report a comprehensive study of the spontaneous magnetization reversal (MRV) performed on the disordered polycrystalline perovskite BiFe(0.5)Mn(0.5)O(3), an intriguing compound synthesized in high pressure-high temperature conditions. In disordered systems, the origin of MRV is not completely clarified, yet. In BiFe(0.5)Mn(0.5)O(3), compositional disorder involves the ions on the B-site of the perovskite determining the presence of mesoscopic clusters, characterized by high concentrations of iron or manganese and thus by different resultant magnetization. This leads to the observation of two singular fields H(1) and H(2) dependent on the degree of inhomogeneity, unpredictably changing from sample to sample due to synthesis effects. These fields separate different magnetic responses of the system; for applied fields H < H(1), the Fe and Mn clusters weakly interact in a competitive way, giving rise to MRV, while for an intermediate field regime the energy of this weak interaction becomes comparable to the energy of the system under field application. As a consequence, the zero field cooled magnetization thermal evolution depends on the sample degree of inhomogeneity. In this field regime, applied field Mössbauer spectroscopy indicates that the iron rich clusters are highly polarized by the field, while the largest part of the material, consisting of AFM clusters characterized by axial anisotropy and uncompensated moments, shows soft or hard magnetism depending on T. Above the higher singular field, the M(T) curves show the trend expected for a classical antiferromagnetic material and the competitive character is suppressed. The MRV phenomenon results to be highly sensitive on both the thermal and magnetic measurement conditions; for this reason the present work proposes a characterization strategy that in principle has a large applicability in the study of disordered perovskites showing similar phenomenology.

Mating-disruption trials for control of Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), in traditional flour mills

In the present work, 3 years of field trials (from 2007 to 2009) were carried out to evaluate use of the pheromone (9Z, 12E)-tetradecadienyl acetate (TDA) for mating disruption (MD) of the Mediterranean flour moth, Ephestia kuehniella Zeller. Dispensers containing the pheromone TDA were placed in two traditional flour mills. Pheromone-baited funnel traps were used to monitor the population fluctuations of E. kuehniella males throughout the entire experimental period; female oviposition was assessed by placement of petri cups containing wheat germ-semolina flour bait. According to our results, the use of MD dispensers does not interfere completely with the reproduction of E. kuehniella. However, looking at the overall data, there was a significant reduction in both adults and larvae in treated mills after the MD application. According to hazard analysis and critical control point procedures, treatment should be accompanied by general cleaning of the facilities, including corners and inside machinery, where insects can hide and reproduce. In integrated pest management programs, the use of mating disruption can lead to a drastic reduction in the need for chemical treatments, with improvement in food quality.

Cardiomyopathy, adult valve disease and heart failure in South America

Continued assessment of temporal trends in mortality and epidemiology of specific cardiovascular diseases in South America is needed to provide a scientific basis for rational allocation of the limited healthcare resources and introduction of strategies to reduce risk and predict the future burden of cardiovascular disease. The epidemiology of cardiomyopathies, adult valve disease and heart failure (HF) in South America is reviewed here. Diseases of the circulatory system are the main cause of death based on data from about 50% of the South American population. Among the cardiovascular causes of death, cerebrovascular disease is predominant followed by ischaemic heart disease, other heart diseases and hypertensive disease. Of note, cerebrovascular disease is the main cause of death in women, and race also influenced cardiovascular mortality rates. HF is the most important cardiovascular reason for admission to hospital due to cardiovascular disease of ischaemic, idiopathic dilated cardiomyopathic, valvular, hypertensive and chagasic aetiologies. Also, mortality due to HF is high, especially owing to Chagas' disease. HF and aetiologies associated with HF are responsible for 6.3% of deaths. Rheumatic fever is the leading cause of valvular heart disease. The findings have important public health implications because the allocation of healthcare resources, and strategies to reduce the risk of HF should also consider controlling Chagas' disease and rheumatic fever in South American countries.

Towards a vaccine against rheumatic fever

Rheumatic fever (RF) is an autoimmune disease which affects more than 20 million children in developing countries. It is triggered by Streptococcus pyogenes throat infection in untreated susceptible individuals. Carditis, the most serious manifestation of the disease, leads to severe and permanent valvular lesions, causing chronic rheumatic heart disease (RHD). We have been studying the mechanisms leading to pathological autoimmunity in RF/RHD for the last 15 years. Our studies allowed us a better understanding of the cellular and molecular pathogenesis of RHD, paving the way for the development of a safe vaccine for a post-infection autoimmune disease. We have focused on the search for protective T and B cell epitopes by testing 620 human blood samples against overlapping peptides spanning 99 residues of the C-terminal portion of the M protein, differing by one amino acid residue. We identified T and B cell epitopes with 22 and 25 amino acid residues, respectively. Although these epitopes were from different regions of the C-terminal portion of the M protein, they showed an identical core of 16 amino acid residues. Antibodies against the B cell epitope inhibited bacterial invasion/adhesion in vitro. Our results strongly indicated that the selected T and B cell epitopes could potentially be protective against S. pyogenes.

Overlapping humoral autoimmunity links rheumatic fever and the antiphospholipid syndrome

OBJECTIVE

Rheumatic fever (RF) and the antiphospholipid syndrome (APS) are autoimmune diseases that share similar cardiac and neurological pathologies. We assessed the presence of shared epitopes between M protein, N-acetyl-beta-D-glucosamine (GlcNAc) and beta2 glycoprotein-I (beta2GPI), the pathogenic molecules engaged in these autoimmune conditions.

METHODS

Sera from the APS patients were affinity-purified on beta2GPI and beta2GPI-related peptide columns. Sera from RF patients were affinity-purified on protein G column. The beta2GPI and M protein-related peptides were prepared by conventional solid-phase peptide synthesis. The enzyme-linked immunosorbent assay direct binding and inhibition studies were performed on the RF and APS sera for the presence, and cross-reactivity, of antibodies against beta2GPI, beta2GPI-related peptides, streptococcal M protein, M-derived peptides and GlcNAc.

RESULTS

Antibodies (Abs) to beta2GPI were found in 24.4% of 90 RF patients. Antibodies against various beta2GPI-related peptides were found in 1.1-36.7% of the patients. The immunoglobulin G sera from RF patients possessed significant anti-beta2GPI activity, while sera from APS patients contained a considerable anti-streptococcal M protein as well as anti-GlcNAc activity. Furthermore, affinity-purified anti-beta2GPI and anti-beta2GPI-related peptide Abs from APS patients cross-reacted with streptococcal M protein and M5 peptide, while beta2GPI and beta2GPI-related peptides inhibited anti-streptococcal M protein activity from RF patients. The results were confirmed by immunoblot analyses. The beta2GPI also inhibited anti-GlcNAc activity from APS patients with chorea.

CONCLUSIONS

The results of our study, showing a considerable overlap of humoral immunity in RF and APS, support a hypothesis that common pathogenic mechanisms underlie the development of cardiac valve lesions and Central Nervous System abnormalities in both diseases.

Vascular prosthetic graft infection: epidemiology, bacteriology, pathogenesis and treatment

Vascular prosthetic graft infection remains a major surgical challenge. Prevention of risk factors and antibiotic therapy can reduced but not eradicate it. Management of infected vascular grafts depends on several factors, including the location of the infected prosthesis, the extent of infection, and the underlying micro-organism. Classic treatment consists of extra-anatomic bypass grafting. The disappointing results due to the high mortality and amputation rate have kindled interest in alternative approaches, such as in situ reconstruction with antibiotic-bonded prostheses, autogenous veins or arterial allografts.

PURPOSE

We focused on the treatment of aortic graft infection by means of both fresh and cryopreserved arterial allograft. Here, the experience of the Italian Collaborative Vascular Homograft Group is reported.

METHODS

Between March 1994 and December 2000 seventy-nine patients with aortic graft infection were treated. The results of 68 patients are analysed. Eleven patients were treated with fresh, and 57 with cryopreserved homograft. Emergency surgical procedures were performed in 12 patients (17%). Aortoenteric fistula was diagnosed in 22 patients. The mean interval between the first procedure and the insertion of a homograft for patients with infected aortic graft was 3 years (range 1-15). The mean duration of follow-up was 30 months (range 1-68). Clinical and duplex scanning evaluation were routinely performed. Computer tomography (CT), magnetic resonance (MR), or arteriography were performed on the basis of duplex scanning results.

RESULTS

The analysis was performed on 68 cases for which there were sufficient reliable data. Eleven deaths occurred during the early postoperative period (30 days), a mortality rate of 16%. There were also seventeen late deaths, a mortality rate of 25%. Eleven patients had graft occlusion; six cases were successfully treated with thrombectomy. In three cases leg amputation was necessary. The results of fresh and cryopreserved homografts were compared. No significant differences of early postoperative mortality, late mortality, homograft-related mortality, graft failure were observed. The presence of aortoenteric fistula is a negative predicting factor of perioperative early mortality, which causes a rapid decline in the survival curve. Thirty-six months after the surgery the actuarial survival of the patients was 57% and the actuarial patency of the allograft was 41%.

CONCLUSION

No significant difference in terms of clinical outcome was observed when using fresh, rather than cryopreserved homografts. The only factor that significantly influenced the survival rate appeared to be the aorto-enteric fistula.

Increased endothelin-1 levels in women with polycystic ovary syndrome and the beneficial effect of metformin therapy

Women with polycystic ovary syndrome who present with hyperandrogenemia, hyperinsulinemia, and insulin resistance appear to be at high risk of cardiovascular disease. Elevated levels of endothelin-1, a marker of vasculopathy, have been reported in insulin-resistant subjects with endothelial dysfunction. Male gender also seems to be an aggravating factor for cardiovascular disease. In this study we investigated endothelin-1 levels in women with polycystic ovary syndrome, and we evaluated the effect of an insulin sensitizer, metformin, on endothelin-1 levels. Plasma endothelin-1 levels were measured in 23 obese (mean age, 24.3 +/- 4.6 yr; body mass index, 35 +/- 5.6 kg/m(2)) and 20 nonobese women with polycystic ovary syndrome (24.1 +/- 3.6 yr; body mass index, 21.8 +/- 2.5 kg/m(2)) as well as in 7 obese and 10 nonobese healthy, normal cycling, age-matched women. Additionally, endothelin-1 levels were evaluated in a subgroup of women with polycystic ovary syndrome (10 obese and 10 nonobese) 6 months postmetformin administration (1700 mg daily). Our results showed that obese and nonobese women with polycystic ovary syndrome had higher levels of endothelin-1 compared with the controls [obese, 2.52 +/- 1.87 vs. 0.44 +/- 0.23 pmol/liter (by analysis of covariance, P < 0.02); nonobese, 1.95 +/- 1.6 vs. 0.43 +/- 0.65 pmol/liter (P < 0.009)]. All of the participating women with polycystic ovary syndrome (n = 43) when compared with the total group of controls (n = 17) demonstrated hyperinsulinemia (polycystic ovary syndrome, 24.5 +/- 19.6; controls, 11.2 +/- 3.4 U/liter; P < 0.03), lower glucose utilization (M40) during the hyperinsulinemic euglycemic clamps (3.4 +/- 2.4 vs. 5.6 +/- 1.75 mg/kg.min; P < 0.045, by one-tailed test), and higher levels of endothelin-1 (polycystic ovary syndrome, 2.52 +/- 1.87; controls, 0.44 +/- 0.23 pmol/liter; P < 0.02, analysis of covariance covariate for body mass index). A positive correlation of endothelin-1 with free T levels was also shown (r = 0.4, P = 0.002) as well as a negative correlation of endothelin-1 with glucose utilization (r = -0.3; P = 0.033) in the total studied population. Finally, after metformin therapy, endothelin-1 levels were significantly reduced in obese (endothelin-1 before, 3.25 +/- 2.2; endothelin-1 after, 1.1 +/- 0.9 pmol/liter; P < 0.003) and nonobese (endothelin-1 before, 2.7 +/- 2; endothelin-1 after, 0.7 +/- 0.4 pmol/liter; P < 0.01) women with polycystic ovary syndrome, with no change in body mass index. Moreover, after metformin therapy, hyperandrogenemia and hyperinsulinemia were normalized, and glucose utilization improved [obese before: total T, 0.9 +/- 0.15 ng/ml; fasting insulin, 22.2 +/- 12.1 U/liter; glucose utilization, 2.15 +/- 0.5 mg/kg.min; obese after: total T, 0.5 +/- 0.2 ng/ml; fasting insulin, 11.6 +/- 6 U/liter; glucose utilization, 4.7 +/- 1.4 mg/kg.min 9P < 0.003, P < 0.006, and P < 0.002, respectively); nonobese before: total T, 1 +/- 0.5 ng/ml; fasting insulin, 15.5 +/- 7.6 U/liter; glucose utilization, 3.4 +/- 0.7 mg/kg.min; nonobese after: total T, 0.8 +/- 0.5 ng/ml; fasting insulin, 9 +/- 3.8 U/liter; glucose utilization, 6 +/- 1.7 mg/kg.min (P < 0.04, P < 0.02, and P < 0.0008, respectively)]. In conclusion, our data clearly demonstrate that women with polycystic ovary syndrome, obese and nonobese, have elevated endothelin-1 levels compared with the age-matched control group. In addition, 6 months of metformin therapy reduces endothelin-1 levels and improves their hormonal and metabolic profile.

Fresh and cryopreserved arterial homografts in the treatment of prosthetic graft infections: experience of the Italian Collaborative Vascular Homograft Group

Following the experience of cardiac surgeons with homografts in the treatment of infective aortic valve endocarditis, cardiovascular surgeons have investigated in situ revascularization by means of homografts in the management of vascular prosthetic graft infections. Preliminary results are encouraging, but their late fate in long-term follow-up and the influence of preservation techniques are still under investigation. This article reports the experience of the Italian Collaborative Vascular Homograft Group, with the use of fresh and cryopreserved arterial homografts for the treatment of prosthetic graft infections. Between March 1994 and December 1996, 44 patients with prosthetic graft infection were treated with homografts (13 preserved at 4 degrees C, 31 cryopreserved). The mean age of the patients was 65 years. Emergency surgical procedures were performed in eight patients (18%). Sepsis was diagnosed in 11 patients, aortoenteric fistula in 13, and false aneurysms in 10. Staphylococcus was the main cause of infection. The types of vascular reconstruction with homograft were: 32 aortobifemoral, 3 aortoaortic, 2 iliofemoral, 4 peripheral, and 3 axillobifemoral. Human lymphocyte antigen (HLA) and antibody (ABO) blood group system compatibility between donors and recipients was not respected. The mean duration of follow-up was 15 months (range 1-33). Clinical and duplex scanning evaluations were routinely performed. Computed tomography (CT) or magnetic resonance (MR) scanning or arteriography were performed on the basis of duplex scanning results. There were six deaths during the early postoperative period (30 days) with a mortality rate of 13.6%. During the follow-up there were five late deaths with a mortality rate of 11.4%. Eight patients had graft occlusion. Three cases were successfully treated with thrombectomy. Two cases were successfully treated with femoropopliteal bypass with autologous vein. In three cases leg amputation was necessary. The results of fresh and cryopreserved homograft were compared. No significative differences of early postoperative mortality, late mortality, homograft related mortality, and graft occlusion were observed. We have evaluated the actuarial survival of the patients and the actuarial patency of the homografts on the aortoiliac reconstructions. Twelve months after the surgery the actuarial survival of the patients was 73% and the actuarial patency of the homografts was 56%. In our preliminary experience, we have not observed any significant difference in terms of clinical outcome by using fresh rather than cryopreserved homografts. In the near future it will be our policy to employ only cryopreserved homografts. Moreover, we will extend vessel harvesting to nonheart-beating donors, thus maximizing retrieval. The aforementioned solutions will supply the best graft availability to obtain dimensional and ABO compatibility between donors and recipients.

Nuclear and Electron Relaxation in Magnetic Exchange Coupled Dimers: Implications for NMR Spectroscopy

The transition probabilities and the lifetimes have been calculated for the levels arising from magnetic exchange coupling in the following electron spin pairs: SA = &frac12;-SB = &frac12;; SA = &frac12;-SB = 1; SA = &frac12;-SB = 32; SA = 1-SB = 1. Such transition probabilities and lifetimes have been expressed as a function of the relaxation properties of the uncoupled spins in the assumption that magnetic coupling does not provide further relaxation pathways, and that the coupling frequency is large with respect to the electron relaxation rates of both spins. From the above values, nuclear relaxation as a function of the intensity of the external magnetic field has been calculated for nuclei dipole-coupled with either electron spin. The calculated nuclear relaxation dispersion has been then analyzed in terms of an "effective" electron relaxation time, the knowledge of which is important for NMR of magnetic coupled systems. The calculations provide a basis for understanding electron relaxation in magnetic-coupled dimers. Comparison with available experimental literature data is presented. Copyright 1998 Academic Press. Copyright 1998 Academic Press

Technical difficulties and complications during laparoscopic cholecystectomy: predictive use of preoperative ultrasonography

The aim of this study was to evaluate ultrasound findings as predictors of potential operative difficulties and complications during laparoscopic cholecystectomy (LC). From October 1993 to June 1995 a total of 143 patients with symptomatic cholelithiasis (50 males, 93 females, mean age 49.5 +/- 15 years) were evaluated by ultrasound (US) the day before LC. The US examination assessed six parameters: gallbladder (GB) volume, GB wall thickness, GB neck position, GB stone mobility, stone maximum size, and GB adhesions. On the basis of these US findings, a predictive judgment of technical difficulties was expressed by degree: easy, difficult, and very difficult. Altogether 101 patients presented with uncomplicated symptomatic cholelithiasis, and 42 had acute cholecystitis. The operation was predicted to be easy in 38% of cases, difficult in 49%, and very difficult in 13% with a good correlation with the surgeon's intraoperative judgment (r = 0.66). A significant association was found between stone mobility (r = 0.37), presence of adhesions (r = 0.36), and the difficulty of the procedure. The predictive US evaluation was significantly correlated with some intraoperative technical steps [dissection of Calot's triangle (r = 0.41), dissection of the gallbladder bed (r = 0.41)], and intraoperative bleeding (r = 0.27). Our results suggest that preoperative US is a useful screening test for patients undergoing LC, and it can help predict technical difficulties. On the other hand, a relevant number of cases still exist wherein the concordance between the preoperative US classification and the surgical findings is unsatisfactory. In this group the surgeon cannot safely rely on the US examination alone.

[Fabry disease, an ophthalmo-neuro-dermato-cardio-nephrologic problem]

We want to present a 47-years-old patient suffering of a histologically and biochemically confirmed M. Fabry. Besides the ocular findings, we list the systemic findings and discuss the diagnostic and therapeutic possibilities. We especially want to point out the interdisciplinary collaboration in dealing with this condition.

[A patient with Kearns-Sayre syndrome]

In addition to ophthalmic symptoms (ptosis and retinitis pigmentosa), our patient displayed symptoms of disturbances of cardial conduction as well a mitochondrial myopathy. The latter was confirmed histologically. The order in which the symptoms of the disease appear may vary, but the close cooperation of ophthalmologist, neurologist and internist is vital in any event.

[The right foreign body at the wrong site]

In ophthalmology like in any other medical field, some natural tissue or a piece of artificial material may be found in an unusual location. We are going to describe two extraordinary clinical cases: a tuft of hair in the conjunctiva and a luxated posterior chamber lens.

The role of portosystemic shunting in the management of portal hypertension

In this chapter, we have tried to indicate the role of the portosystemic shunt in the treatment of portal hypertension. The conclusions are evident: in the last 10 years it has lost its role as leader in the treatment of portal hypertension. However, some firm statements can be made. The selective shunt is an operation that provides both good variceal decompression and satisfactory maintenance of liver function. Its results in great part depend on the skill of the surgeon. Only a patient with good liver function (Child's classes A and B) is a candidate for shunt surgery, with, very occasionally, a patient with severe disease (class C). In an emergency, the operation is used only after failure of sclerotherapy, but it must be used at the right time before the patient's condition has deteriorated. In the prevention of variceal rebleeding, the selective shunt or sclerotherapy can be routine measures. The choice between the two treatments depends on the patient's willingness and the ability of the institution to perform both procedures successfully. If sclerotherapy is chosen, the institution must be able to rapidly rescue a sclerotherapy failure by shunt surgery. Liver transplantation is probably the treatment of the future, but it is at present impossible to suggest that the procedure is feasible for all patients with variceal bleeding and severe liver disease.

Clinical utility of the serum CA 19-9 test for diagnosing pancreatic carcinoma in symptomatic patients: a prospective study

The diagnostic accuracy of the serum CA 19-9 determination was prospectively evaluated in patients selected for the presence of signs or symptoms highly suggestive for pancreatic cancer. Of 110 patients included in the study, 54 had a final diagnosis of pancreatic adenocarcinoma (49% prevalence). CA 19-9 values were higher than 40 U/ml in 45 patients with pancreatic carcinoma and in 18 of the 56 patients with other final diagnosis (sensitivity, 0.83; specificity, 0.68; positive predictive value [PPV], 0.71; negative predictive value [NPV], 0.81). The serum CA 19-9 determination was not capable of shortening the diagnostic workup of patients with strong clinical suspicion of pancreatic cancer since adequate imaging of the pancreas was required to confirm or exclude the diagnosis. However, values above 120 U/ml were strongly suggestive for pancreatic carcinoma in the overall population (PPV, 0.85) and they were diagnostic (PPV, 1.0) in the anicteric portion. Combined with pancreatic imaging, the CA 19-9 was an excellent confirmatory test; a normal value in a patient with negative imaging ruled out pancreatic carcinoma as the cause of symptoms (NPV, 1.0), whereas a pathological result in the presence of positive or equivocal pancreatic radiology was highly suggestive for the presence of the disease (PPV, 0.93).

[Endocrine-metabolic response to 2 different techniques in surgery of the abdominal aorta]

Plasma cortisol and PRL were measured in two groups of patients undergoing reconstructive aortic surgery under either general anaesthesia and continuous epidural analgesia with supplemental general anaesthesia. The results confirmed that epidural analgesia with light general anaesthesia is much able than general anaesthesia to suppress the metabolic response associated with aortic surgery procedures.

[Pepper and salt fundus and family anamnesis in congenital syphilis]

Recognizing congenital syphilis in pediatric patients is of utmost importance with regard to therapy. The case of a 5-year-old girl with salt and pepper fundus demonstrates the importance of a thorough family history which led towards the diagnosis of congenital syphilis. This paper stresses the importance of family history in pigmented lesions of the fundus.

[Tumorous eyelid changes in systemic diseases]

Lid tumors appear to invite the physician to make a diagnosis at first glance. This poster displays examples of lid tumors that occur in the context of malignancies, inflammatory and metabolic diseases and phacomatoses. The most frequent primary sites in metastatic eyelid tumors are the breast, the lung and cutaneous melanoma. Because of their comparatively low incidence and variable appearance these lid tumors are, at least in the beginning, often misinterpreted. Careful differential diagnosis may help in avoiding the diagnostic pitfalls of the masquerade syndromes. Lid tumors associated with sarcoidosis, lupus erythematosus discoides, lupus vulgaris, syphilis are briefly mentioned. Xanthelasmas occur more frequently in diabetics than in the normal population. About 5% of patients with xanthelasma suffer from hyperlipidemia. Neurofibromas and cavernous hemangiomas of the lid may accompany von Recklinghausen's and Sturge-Weber's diseases.

[Is vision measurement by vision tables accurate?]

We observed that often visual tables are different, so that one patient can be shown to have different visual acuities. We show the more important characteristics that a standardized visual table should have.

[A propofol-ketamine combination in short-term anesthesia]

The authors report the results of a study in 43 patients anesthetized using Propofol + Ketamina. The results seem to stage that the two drugs have complementary effects. Propofol and Ketamina used together and infused inravenously have given better results, and less kinds of complementary effects than usual techniques.

Angioscintigraphic assessment of hemodynamic effects of penbutolol in cirrhotics with portal hypertension. A double-blind, randomized, controlled study

This randomized double-blind controlled study analyzed the hemodynamic effects of penbutolol, a new levorotatory beta-blocker, using radionuclide angiography. Twenty cirrhotics with esophageal varices were randomized to two groups: 10 received 40 mg/day of penbutolol orally and the others placebo. Angioscintigraphy was performed before and after an 8-day treatment period. Three cases in the penbutolol group were lost due to software damage, hence the data of 17 patients were analyzed. The two groups were matched for age, sex, etiology of cirrhosis and hepatic function. The index of portal perfusion decreased significantly (-29%; p = 0.018) and the hepatic artery index increased significantly (+23%; p = 0.018), while no changes were observed after placebo. The heart rate decreased significantly after penbutolol (-9%; p = 0.028), while neither penbutolol nor placebo modified the ejection fraction. In conclusion, penbutolol decreased portal perfusion index (the compensatory increase in the hepatic artery index confirmed this change) without major modification of total hepatic blood flow or systemic hemodynamics. Angioscintigraphy is reasonably accurate, reproducible, safe and can be considered suitable for routine use in the assessment of liver hemodynamics.

Prevalence of hepatitis B virus (HBV) in Italian adolescents

Prevalence of HBV markers (HbsAg, anti-Hbs, anti-HBc) was retrospectively estimated in 204 adolescents (12-20 years old) of the Bambino Gesù Hospital (174 patients of orthopaedic department and 30 student nurses). HBsAg carrier rate was 3.4% (all healthy, none HBeAg positive) and prevalence of HBV marker (at least one positive) was 13.2%. Male sex, residence in the south of Italy or Italian islands, being inpatients, past surgical procedures and past hepatitis showed higher prevalences, but never significantly; anti-HBc prevalence was significantly higher in patients with a previous surgical procedure with transfusions. Future vaccinations should take into account the substantial HBV infection rate occurred as early as in adolescence.

Pancreatic polypeptide response to food and cerulein in patients with total gastrectomy

In order to investigate the intestinal phase of pancreatic polypeptide (PP) release, the hormonal response to food and cerulein was measured in 19 patients with truncal vagotomy and total gastrectomy (10 with simple esophagojejunal anastomosis and 9 with an additional duodenojejunal anastomosis) and in 7 healthy subjects. After gastrectomy, the early peak of the physiologic biphasic PP response to food was lost but the late predominant phase was unchanged so that the overall postprandial release of the hormone was not significantly lowered. Gastrectomized patients with duodenal bypass had postprandial serum levels only slightly lower than those of patients with preserved duodenal transit of food. Serum PP response to cerulein stimulation was significantly lower in vagotomized patients than in healthy subjects. However, in operated patients as well as in controls, cerulein infusion did induce a rapid increase of plasma PP, followed by persistently elevated levels. The PP response to cerulein was abolished by atropine pretreatment. Our findings indicate that the intestinal phase of meal-stimulated PP response is not dependent on the integrity of vagal pancreatic innervation and that the preservation of the duodenal transit of food after total gastrectomy is not crucial for the maintenance of the enteroinsular axis.

Improved quality of life after distal splenorenal shunt. A prospective comparison with side-to-side portacaval shunt

The distal splenorenal shunt (DSRS) was compared with the side-to-side portacaval shunt (PCS) in 93 prospectively matched patients with portal hypertension. After 38 months mean follow-up the two shunts had a different incidence of acute encephalopathy (22% in PCS group and 33% in DSRS group) and chronic encephalopathy (35% in PCS group and 17% in DSRS group), but the difference was not statistically significant. However, the only cases of severe and disabling chronic encephalopathy arose after PCS (p = 0.049). Actuarial curves of chronic encephalopathy showed that the maximum rate of encephalopathy (18%) in the DSRS group was reached 27 months after shunt surgery, whereas this value was reached and passed in PCS group only 4 months after shunt. Chronic encephalopathy occurred for a total duration of 20.1 months after PCS and only 11.1 months afer DSRS (p = 0.003) and occupied 46.3% of the follow-p of PCS patients, as contrasted to 18.7% of the follow-up of DSRS patients (p = 0.0001). DSRS is associated with a lower global incidence of chronic HE without severe forms and provides a better quality of life than does a nonselective shunt.