Semiautomatic detection of villi in confocal endoscopy for the evaluation of celiac disease.

Celiac Disease (CD) is an immune-mediated enteropathy, diagnosed in the clinical practice by intestinal biopsy and the concomitant presence of a positive celiac serology. Confocal Laser Endomicroscopy (CLE) allows skilled and trained experts to potentially perform in vivo virtual histology of small-bowel mucosa. In particular, it allows the qualitative evaluation of mucosa alteration such as a decrease in goblet cells density, presence of villous atrophy or crypt hypertrophy. We present a semi-automatic method for villi detection from confocal endoscopy images, whose appearance change in case of villous atrophy. Starting from a set of manual seeds, a first rough segmentation of the villi is obtained by means of mathematical morphology operations. A merge and split procedure is then performed, to ensure that each seed originates a different region in the final segmentation. A border refinement process is finally performed, evolving the shape of each region according to local gradient intensities. Mean and median Dice coefficients for 290 villi originating from 66 images when compared to manually obtained ground truth are 80.71% and 87.96% respectively.

Estimation of prenatal aorta intima-media thickness from ultrasound examination.

Prenatal events such as intrauterine growth restriction and increased cardiovascular risk in later life have been shown to be associated with an increased intima-media thickness (aIMT) of the abdominal aorta in the fetus. In order to assess and manage atherosclerosis and cardiovascular disease risk in adults and children, in recent years the measurement of abdominal and carotid artery thickness has gained a growing appeal. Nevertheless, no computer aided method has been proposed for the analysis of prenatal vessels from ultrasound data, yet. To date, these measurements are being performed manually on ultrasound fetal images by skilled practitioners. The aim of the presented study is to introduce an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from routine third trimester ultrasonographic fetal data.The algorithm locates the aorta, then segments it and, by modeling the arterial wall longitudinal sections by means of a gaussian mixture, derives a set of measures of the aorta diameter (aDiam) and of the intima-media thickness (aIMT). After estimating the cardiac cycle, the mean diameter and the aIMT at the end-diastole phase are computed.Considering the aIMT value for each subject, the correlation between automatic and manual end-diastolic aIMT measurements is 0.91 in a range of values 0.44-1.10 mm, corresponding to both normal and pathological conditions. The automatic system yields a mean relative error of 19%, that is similar to the intra-observer variability (14%) and much lower that the inter-observer variability (42%).The correlation between manual and automatic measurements and the small error confirm the ability of the proposed system to reliably estimate aIMT values in prenatal ultrasound sequences, reducing measurement variability and suggesting that it can be used for an automatic assessment of aIMT.

Left ventricular modelling: a quantitative functional assessment tool based on cardiac magnetic resonance imaging.

We present the development and testing of a semi-automated tool to support the diagnosis of left ventricle (LV) dysfunctions from cardiac magnetic resonance (CMR). CMR short-axis images of the LVs were obtained in 15 patients and processed to detect endocardial and epicardial contours and compute volume, mass and regional wall motion (WM). Results were compared with those obtained from manual tracing by an expert cardiologist. Nearest neighbour tracking and finite-element theory were merged to calculate local myocardial strains and torsion. The method was tested on a virtual phantom, on a healthy LV and on two ischaemic LVs with different severity of the pathology. Automated analysis of CMR data was feasible in 13/15 patients: computed LV volumes and wall mass correlated well with manually extracted data. The detection of regional WM abnormalities showed good sensitivity (77.8%), specificity (85.1%) and accuracy (82%). On the virtual phantom, computed local strains differed by less than 14 per cent from the results of commercial finite-element solver. Strain calculation on the healthy LV showed uniform and synchronized circumferential strains, with peak shortening of about 20 per cent at end systole, progressively higher systolic wall thickening going from base to apex, and a 10° torsion. In the two pathological LVs, synchronicity and homogeneity were partially lost, anomalies being more evident for the more severely injured LV. Moreover, LV torsion was dramatically reduced. Preliminary testing confirmed the validity of our approach, which allowed for the fast analysis of LV function, even though future improvements are possible.

[Gadolinium for DSA in two patients with azotemia: Images of suitable quality and risk of acute renal failure]. / Angiografia con Gadolinio in due pazienti azotemici: la qualita' diagnostica ed il rischio d'insufficienza renale acuta.

BACKGROUND: Gadolinium is an alternative angiographic contrast agent in patients with impaired renal function and high risk for iodinated contrast adverse reaction. We report two cases of acute renal failure caused by gadolinium (0.6 and 0.9 mmol/kg of body weight) after the execution of digital subtraction angiography (DSA) to produce diagnostic-quality images in two elderly diabetic patients with pre-existing renal insufficiency. Both patients needed dialysis treatments for as long as a few weeks until their renal function improved. In our opinion, and according to the guidelines of European Society of Urogenital Radiology, gadolinium has not been assessed as less nephrotoxic than iodinated contrast agents. In fact, 1.8 to 4.8 g of iodine, equally attenuated with a relatively high dose (0.2 to 0.4 mmol) of a gadolinium chelate, is a low iodine dose and could hardly have any important nephrotoxic effects. CONCLUSIONS: The maximum dose of gadolinium-based contrast agents should never exceed 0.2 to 0.4 mmol/kg in azotemic patients who are undergoing DSA, even though these doses of gadolinium may not provide images of suitable quality for diagnosis and intervention.

[Local therapy with platelet-derived growth factors for chronic diabetic ulcers in haemodialysis patients]. / Terapia locale con fattori di crescita piastrinici nelle ulcere croniche diabetiche in emodializzati.

BACKGROUND: The increasing number of diabetic patients who need dialysis treatment is the cause for the growing interest of nephrologists in ulcers of the lower limbs. It has been reported that platelet-derived growth factors, such as PDGF and TGF beta 1, are able to heal skin lesions due to diabetes. Therefore, a platelet gel (PG) has been developed to locally treat foot ulcers with a limited number of applications (3+/-1.7). METHOLOGY AND PATIENTS: The PG is a mix of concentrated platelets and cryoprecipitate activated by batroxobin in the presence of calcium chloride (or gluconate) that must be applied to the wound for three days. The surgeon and the dermatologist should then plan successive treatments because the necrotic tissue needs to be removed. We treated a 62-year-old diabetic man, who has been under treatment with insulin since the age of 36 and has been dialysed for three years. His right lower leg was amputated and he developed a chronic left foot ulcer that resulted in many septic episodes. His ulcer recovered in two months after 8 PG applications. CONCLUSIONS: Conventional therapy is not successful in 15-20% of diabetic feet. Uraemia and malnutrition may represent important risk factors for foot ulcers in diabetic patients who need advanced technology to stimulate tissue repair. The use of platelet growth factor may ameliorate ulcer healing thus reducing disease-associated morbidity and lowering health care costs.

Clinical characteristics associated to atrial fibrillation in chronic hemodialysis patients.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia diagnosed in non-uremic patients and its prevalence increases in older subjects, however, information concerning AF in dialysis patients is scarce. Therefore, we carried out a prospective cross-sectional study from September 1996 to December 1996 in order to evaluate the prevalence and some of the clinical characteristics associated to AF in hemodialysis (HD) patients. SUBJECTS AND METHODS: 316 HD patients (age 63 +/- 12 years, dialysis duration 69 +/- 71 months) treated in three different hospital-based units were studied. Standard 12-lead electrocardiograms (ECGs) carried out in the interdialytic day during the study period were reviewed. Data concerning age, history of ischemic heart disease (IHD), cerebrovascular disease (CVD), peripheral vascular disease (PVD), presence of diabetes, smoking history and antihypertensive therapy were collected. Systolic and diastolic blood pressure, fasting cholesterol and triglycerides, albumin and hemoglobin were also derived from the clinical records. Performance status was assessed by Karnofsky index (Ki). RESULTS: 74 patients (23.4%) had persistent AF, i.e. presence of AF in all (at least two) ECGs performed in the study time. Patients with AF were older (age 69 +/- 10 vs 62 +/- 12 years, p < 0.001), had lower Ki (54 +/- 20 vs 68 +/- 17, p < 0.01), cholesterol (182 +/- 46 vs 198 +/- 52 mg/dl, p < 0.01) and albumin (3.9 +/- 0.5 vs 4.1 +/- 0.5 g/dl, p < 0.001) compared to those with no AF. Prevalence of IHD (44.5% vs 19%, p < 0.05) and PVD (23% vs 11%, p < 0.05) was higher among AF patients. Logistic regression analysis showed that IHD (p < 0.001) and Ki (p < 0.01) were independently associated to AF. CONCLUSION: We conclude that AF is a frequent arrhythmia in HD patients treated in hospital-based dialysis units, especially in those with low performance status. It appears to be associated to the atherosclerotic damage of coronary arterial tree. Prospective studies are necessary to assess whether it could contribute to cardiovascular morbidity and mortality in end-stage renal disease.

Failing hemodialysis arteriovenous fistula and percutaneous treatment: imaging with CT, MRI and digital subtraction angiography.

PURPOSE: To evaluate failing hemodialysis arteriovenous fistulas with helical CT angiography (CTA), MR angiography (MRA), and digital subtraction angiography (DSA), and to compare the efficacy of the three techniques in detecting the number, location, grade, and extent of stenoses and in assessing the technical results of percutaneous transluminal angioplasty (PTA) and stenting. METHODS: Thirteen patients with Brescia-Cimino arteriovenous fistula malfunction underwent MRA and CTA of the fistula and, within 1 week, DSA. A total of 11 PTAs were performed; in three cases an MR-compatible stent was placed. DSA served as the gold standard for comparison in all patients. The presence, site, and number of stenoses or occlusions and the technical results of percutaneous procedures were assessed with DSA, CTA, and MRA. RESULTS: MRA underestimated a single stenosis in one patient; CTA and MRA did not overestimate any stenosis. Significant artifacts related to stent geometry and/or underlying metal were seen in MRA sequences in two cases. CONCLUSIONS: CT and MRI can provide information regarding the degree of vascular impairment, helping to stratify patients into those who can have PTA (single or multiple stenoses) versus those who require an operative procedure (occlusion). Conventional angiography can be reserved for candidates for percutaneous intervention.

Health status and internal radiocontamination assessment in children exposed to the fallout of the Chernobyl accident.

The Chernobyl fallout caused release of radioisotope contaminants in a very large area that includes Belarus, the Ukraine, and the Russian Federation. In this study, the authors monitored the health status and level of internal contamination in 422 children who resided in the aforementioned areas and who were < or = 10 y of age at the time of the accident. The children came to Italy for a 1-mo period between 1991 and 1992. During this time, the children underwent pediatric checkups and biochemical, immunological, and thyroid analyses. All children underwent whole-body counter measurements, and urine radiotoxicological analysis was performed for 224 of them. The 24 children evacuated from Pripiat, a village very close to the Chernobyl reactor site, were selected for cytogenetic analysis. All of these children continue to have a detectable internal contamination of caesium radioisotopes. This condition is likely the result of ground and foodstuff contamination in the various areas. The children did not evidence overt pathologies related to ionizing radiation. However, minor alterations in immunological and thyroid parameters were observed in the group of the evacuated children. Traditional cytogenetic dosimetry was not possible, but the occurrence of acentric fragments was observed-indicating a persistent effect of continuous exposure to low doses of radiation.

The self-locating catheter: clinical evaluation and comparison with the Tenckhoff catheter.

BACKGROUND: Peritoneal catheter displacement appears to be related to various causes including omental attachment, bowel contractions, peritoneal adhesions, and the catheter floating in the dialysis fluid. In order to prevent this complication, which can impair peritoneal dialysis efficacy, Di Paolo et al. designed a "self-locating catheter" (SLC) that is similar to the Tenckhoff catheter (TC) and includes a small tungsten cylinder (weight 12 g) at the distal end (Di Paolo N, et al. The self positioning catheter. Proceedings of the VII Italian Congress on Peritoneal Dialysis. Milan: Wichtig Editore, 1993:539-42). The weight of the tip prevents the catheter from floating and migrating by gravitation toward the Douglas cavity. OBJECTIVE: Starting in 1996, we implanted SLC in 15 continuous ambulatory peritoneal dialysis patients. The aim of our study was to compare the ratio of migration and other catheter-related complications between patients with SLC (196 patient-months) and 13 patients with conventional straight TC (295 patient-months). RESULTS: Peritonitis ratio, catheter complication rate, dialysate inflow and outflow, and weekly creatinine clearance were similar in the two groups of patients. The incidence of catheter displacement was significantly higher (p = 0.0349) in theTC group than in the SLC group (4 vs 0). CONCLUSION: In our experience, the SLC seems to be useful in preventing catheter migration by continuous gravitation of its extremity toward the pelvic cavity.

Beneficial effects of verapamil in renal-risk surgical patients.

OBJECTIVE: To test whether the administration of calcium channel antagonists, such as verapamil (V), on the day before, during, and for 24-36 h after an important abdominal intervention, can lower the onset of acute renal failure (ARF), mostly in renal-risk patients, such as the aged. DESIGN: Randomized, nonblinded study. SETTING: Three surgical care university departments and two intensive care units of the same hospital (S. Anna, Ferrara, Italy). PATIENTS: Thirty-five elderly patients (61-83 years old) entered the study: 18 of them were given V; 17 were not treated and were considered as controls. The two study groups were overlapping as regards age, renal risk, and surgical challenge. The patients who underwent ARF (5 in the treated group, 7 among the controls) were rejected from the study. INTERVENTIONS: V was given on the eve of surgery at a dose of 80 mg/8 h per os and then through slow infusion (5 mg/4-6 h) during the next intra- and postoperative 24-36 h. Abdominal surgery was performed owing to gastric cancer (8 cases), colorectal neoplasia (10 cases), gallstone disease (4 cases), subrenal aortic aneurysm (6 cases), and iliofemoral obstructive arteriopathy (7 cases). MEASUREMENTS: Serum creatinine (SCr) was assessed to test renal function; 24-h urinary levels of brush-border enzymes (gamma glutamyl transferase, or gGT), lysosomal enzymes (N-acetyl-beta-D-glucosaminidase, or NAG), and beta 2-microglobulin (or beta 2M) were determined at T0 (on the eve of surgery), T1 (first and second day after), and T2 (7th and 8th day after) to demonstrate possible tubule cell damage. RESULTS: In the evaluated patients (13 treated with V and 10 untreated): (a) the 24-h urinary levels of gGt and NAG persisted unchanged throughout the study in the treated patients, whereas in the controls the same indices exhibited significant (p < 0.01) increases at T1 and T2; (b) the 24-h urinary levels of beta 2M showed significant (p < 0.01) increases in both groups from T0 to T1; however, at T2 these values tended to return to normal ranges in the treated patients, whereas they continued to be elevated in the untreated group. As regards the patients who underwent postoperative ARF, in the treated group urine output was significantly larger (p < 0.01 at T1 and p < 0.001 at T2), SCr was significantly (p < 0.05) lower, and the renal function recovered earlier (within 10 +/- 3 vs. 22 +/- 9 days) than in the controls. CONCLUSIONS: The administration of calcium channel antagonists to renal-risk patients during surgery and immediately before and after it has failed to prevent the onset of postoperative ARF. Nevertheless this procedure has been shown to somehow reduce surgery-mediated lesions of the tubule cells, as demonstrated by the finding of elevated urinary enzymes only in the untreated group.

Familial interstitial nephropathy without hyperuricemia.

Progressive hereditary nephropathy is described in 6 members of a single family. Renal biopsies, performed in 3 patients, revealed tubular atrophy, interstitial fibrosis, and lymphomonocytic infiltration associated with severe vascular lesions. These features were disproportionately serious when related to age, arterial pressure, and renal function. Similar familial nephropathy has been reported in the literature, generally in association with gout or asymptomatic hyperuricemia. The patients described here had normal blood concentrations of uric acid. It is proposed that the members of the present group of patients are suffering from the same interstitial nephropathy as that described in the literature and that the hyperuricemia found by other investigators is coincidental and does not play a pathogenetic role.

Lipoprotein abnormalities in hypertriglyceridaemic patients on long-term haemodialysis.

OBJECTIVES: To analyse by ultracentrifugation in a zonal rotor the plasma lipoproteins in hypertriglyceridaemic patients on long-term haemodialysis. DESIGN: Case-control study. SETTING: Tertiary referred care centre. SUBJECTS: Ten consecutive hypertriglyceridaemic patients on haemodialysis and 12 consecutive healthy controls. MAIN OUTCOME MEASURES: Plasma lipid and lipoprotein cholesterol concentrations, lipoprotein physical properties and compositions, apolipoprotein concentrations. RESULTS: Hypertriglyceridaemia in patients undergoing haemodialysis is characterized by an increased amount of small and slow floating very-low density lipoproteins (VLDL), higher concentrations of intermediate density lipoproteins (IDL) and small and dense low-density lipoprotein (LDL) particles; reduced levels of high-density lipoproteins (HDL), in particular of HDL2. The lipoprotein composition of such patients indicates reduced cholesterol ester and increased triglyceride content. Compared to controls, they have lower levels of plasma apolipoprotein A-I and A-II and higher B, C-II, C-III and E values. CONCLUSIONS: The lipoprotein abnormalities observed in hypertriglyceridaemic patients undergoing haemodialysis have recently been associated with an increased incidence of vascular complications and may in part explain the high incidence of vascular disease reported in these subjects.

Skin lesions in kidney transplant recipients.

A complete examination of the skin was performed in 53 kidney transplant recipients. Cutaneous lesions were detected in almost all patients. Papillomavirus infections, premalignant and malignant lesions represent the greatest risk for these patients. Our study underlines the importance of a continuous observation to facilitate early diagnosis and treatment of these lesions.

Loss of nocturnal increase in plasma concentration of atrial natriuretic peptide in hypertensive chronic renal failure.

Diurnal change of plasma atrial natriuretic peptide (ANP) concentration was investigated in 12 patients with hypertension due to chronic renal failure (CRF) and in 12 patients with essential hypertension (EH) of comparable degree. Blood pressure (BP) monitoring was performed at 15-min intervals, while peripheral blood samples were obtained at 4-hour intervals starting from 8.00 h. The mean 24-hour plasma levels (+/- SEM) of ANP were 24.3 +/- 1.8 pmol/l in EH and 23.4 +/- 1.2 pmol/l in CRF. In EH, plasma ANP concentration was highest at 4.00 h (33.5 +/- 0.8 pmol/l) and lowest at 16.00 h (15.5 +/- 0.6 pmol/l). In CRF, no significant circadian change was present (22.2 +/- 3.1 and 20.4 +/- 3.6 pmol/l, respectively), and the nocturnal fall in BP was lost. Our data demonstrate that in CRF the loss and possible reversal of the nocturnal decline in BP is associated with the disappearance of any significant circadian variation in the circulating concentrations of ANP. These findings suggest a role for ANP in the alteration of BP variability of CRF, possibly mediated by autonomic dysfunction, and are further evidence for the existence of a relation between the circadian rhythms of ANP and BP.

A modelistic approach to evaluate the factors affecting the 137Cs transfer from mother to fetus in cattle.

The authors have analysed the relationship between 137Cs radioactivity and pregnancy in cattle with radiometric analysis of muscle, kidney and liver of 24 cattle at various stages of pregnancy, fed with fodder exposed to radioactive fall-out. Also the relative fetal muscle, kidney, liver and myocardium have been analysed. The automatic spectra analysis and the statistical one have given the following results: there is no correlation between 137Cs retention and the pregnancy stage in the cattle sampled; the absolute 137Cs concentration is always larger in the kidney than in the muscle (Km/Mm = 1.7), while it is just minor in minor in the liver (Lm/Mm = 0.8). The fetal concentration in muscle, kidney and liver is generally homogeneous, whereas the myocardium tends to retain more 137Cs in the first stages of the pregnancy as against the other tissues. In the last stage of pregnancy it presents a lower concentration. The authors have included the fetal body weight growth to get a more realistic description of the 137Cs transfer in the mother-fetus system; this approach enables to evaluate the kinetic constants so introduced.

An indication on the biological variability of aerosol total deposition in humans.

A technique for the assessment of the total deposition efficiency, DE, in the human respiratory tract is described. It is based on the use of non-wettable solid spherical monodisperse particles in the 0.3 to 1.5 micron range and on the measurement of particle concentrations in the inhaled and exhaled air. The results of total deposition measurements as a function of particle size taken on 6 volunteers are presented. A wide variability has been found among the subjects; it is discussed and, in contrast with some literature data, there is no apparent correlation with normal expiratory reserve volumes, ERVN. Therefore at 0.6 micron the deposition has been measured at various ERV. The scatter of data is considerable, but it can be greatly reduced if the relative deposition (ratio of the effective DE to DEN, the deposition at "normal" volumes) is expressed as a function of the relative ERV, (the ratio of the effective ERV to the normal ERVN). Measurements have been performed with monodisperse and unipolarly charged particles on two subjects characterized by different DEN and ERVN. The contribution of electrostatic effects to deposition was not distinguishable in the two subjects.

Inhalation of a radioactively labeled monodisperse aerosol in rats for the assessment of regional deposition and clearance.

Unanesthesized male Sprague-Dawley rats, averaging 261 g of weight (s.d. = 9 g), were exposed to a radioactively (198Au) labeled monodisperse carnauba wax aerosol, whose AMMD was 0.54 micrometers with a sigma g of 1.1, to determined the alveolar deposition and clearance of particles. Results indicate that 74% of the initial lung burden is cleared in phase one with a T/2 of 11 hours. The remaining 26%, conventionally considered to be the alveolar deposit, is cleared with a T22 of 320 hours. Excised lungs from serial sacrifices have also been measured. The retention curve resulting form the pooled lung data per each day compared well with the curve of the whole animals counted in vivo.