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C Catalano

Publications and source records attributed to C Catalano.

At least 73 records · Page 4Linked to original sources

[Virtual endoscopy with a volumetric reconstruction technic: the technical aspects].

OBJECTIVE: We analyze the peculiar technical features of virtual endoscopy obtained with volume rendering. MATERIAL AND METHODS: Our preliminary experience is based on virtual endoscopy images from volumetric data acquired with spiral CT (Siemens, Somatom Plus 4) using acquisition protocols standardized for different anatomic areas. Images are reformatted at the CT console, to obtain 1 mm thick contiguous slices, and transferred in DICOM format to an O2 workstation (Silicon Graphics, Mountain View CA, USA) with processor speed of 180 Mhz, 256 Mbyte RAM memory and 4.1 Gbyte hard disk. The software is Vitrea 1.0 (Vital Images, Fairfield, Iowa), running on a Unix platform. Image output is obtained through the Ethernet network to a Macintosh computer and a thermic printer (Kodak 8600 XLS). RESULTS: Diagnostic quality images were obtained in all the cases. Fly-through in the airways allowed correct evaluation of the main bronchi and of the origin of segmentary bronchi. In the vascular district, both carotid strictures and abdominal aortic aneurysms were depicted, with the same accuracy as with conventional reconstruction techniques. In the colon studies, polypoid lesions were correctly depicted in all the cases, with good correlation with endoscopic and double-contrast barium enema findings. In a case of lipoma of the ascending colon, virtual endoscopy allowed to study the colon both cranially and caudally to the lesion. The simultaneous evaluation of axial CT images permitted to characterize the lesion correctly on the basis of its density values. DISCUSSION: The peculiar feature of volume rendering is the use of the whole information inside the imaging volume to reconstruct three-dimensional images; no threshold values are used and no data are lost as opposite to conventional image reconstruction techniques. The different anatomic structures are visualized modifying the reciprocal opacities, showing the structures of no interest as translucent. The modulation of different opacities is obtained modifying the shape of the opacity curve, either using pre-set curves or in a completely independent way. Other technical features of volume rendering are the perspective evaluation of the objects, color and lighting. In conclusion, volume rendering is a promising technique to elaborate three-dimensional images, offering very realistic endoscopic views. At present, the main limitation is represented by the need of powerful and high-cost workstations.

Aged↗

MR cholangiography (MRC) in the evaluation of CBD stones before laparoscopic cholecystectomy.

BACKGROUND: The aim of our work was to evaluate the predictive value of MR cholangiography (MRC) in detecting CBD stones before laparoscopic surgical treatment. METHODS: MRC was performed as a unique preoperative imaging modality in 45 selected patients (16 male; 29 female; age range: 28-72; mean age: 54.4) before laparoscopic cholecystectomy. MRC imaging was obtained with a 3D Turbo Spin-Echo sequence (TR = 3000 ms, TE = 700 ms, Echo Train Length--128) with an acquisition time of 5 min 48 s. Diagnostic confirmation was obtained in all the cases at i.o. cholangiography. When a stone was detected it was removed by transcystic or transcholedochal approach. RESULTS: Eighteen of the 45 patients (40%) had CBD stones. MRC correctly evaluated 16 out of 18 stones, with a resulting sensitivity of 88.9%, specificity 100%, positive predictive value 100%, negative predictive value 90%, and accuracy 95.6%. CONCLUSIONS: Despite the good results of MRC, it cannot be proposed as a screening technique to be performed in all patients submitted to laparoscopic cholecystectomy due to high cost and the limited amount of MR equipment. In conclusion, only selected patients should be submitted to MRC before laparoscopic cholecystectomy.

Adult↗

Reciprocal association between insulin sensitivity and the haematocrit in man.

In epidemiological studies, a high haematocrit has been associated both with increased cardiovascular risk and with hyperinsulinaemia, a surrogate of insulin resistance. To examine directly the relationship between the haematocrit and insulin sensitivity, we studied 12 healthy volunteers and 12 patients with non-insulin-dependent diabetes mellitus (NIDDM) with the use of a 4-hour hyperinsulinaemic [1 mU min-1 kg-1] isoglycaemic clamp. In the whole group, insulin sensitivity (as the ratio of insulin-mediated glucose clearance to steady-state plasma insulin concentrations) was inversely related to the haematocrit (r = 0.50, P < 0.01). To test whether acute changes in the haematocrit affect insulin sensitivity, in two NIDDM patients and three healthy subjects the clamp study was repeated after lowering (-18%) the haematocrit by erythro-apheresis. In all five subjects, the lower haematocrit was associated with slightly reduced (-7% on average, P = NS) rather than increased insulin sensitivity. We conclude that insulin sensitivity is inversely related to the haematocrit independently of the glucose tolerance status. The association does not result from acute haemodynamic effects on insulin sensitivity, and may therefore reflect an action of insulin resistance/ hyperinsulinaemia on blood viscosity, or the presence of a common determinant.

Adult↗

Role of MR venography in the evaluation of deep venous thrombosis.

PURPOSE: MR venography has been recommended for the evaluation of deep venous thrombosis. The purpose of our study was to determine the role of MR venography, in particular at the level of the pelvis where other diagnostic modalities show major limitations. MATERIALS AND METHODS: Forty-three patients with clinical suspicion of deep venous thrombosis were examined by means of pelvic MR venography. In all cases, a 2D-TOF sequence was used with cranial arterial presaturation. In selected cases, i.e. when a small intraluminal filling defect was present, a cine-PC sequence was used in addition in order to exclude the presence of a pulsatility artifact as causing the filling defect. In all cases, contrast venography was also performed and considered to be the standard of reference. RESULTS: MR venography showed 26 patients to be positive for deep venous thrombosis at the pelvic level. These positive results were correct in 25 cases. The analysis of the results provided values of sensitivity and specificity of respectively 100% and 94%, with an overall accuracy of 97.6%. CONCLUSIONS: Our results indicate that MR can provide highly accurate images, similar to those of contrast venography, in a noninvasive fashion. It is particularly useful in the pelvic region where the limitations of other imaging modalities are more evident.

Contrast Media↗

Mutations in Nu1, the gene encoding the small subunit of bacteriophage lambda terminase, suppress the postcleavage DNA packaging defect of cosB mutations.

The linear double-stranded DNA molecules in lambda virions are generated by nicking of concatemeric intracellular DNA by terminase, the lambda DNA packaging enzyme. Staggered nicks are introduced at cosN to generate the cohesive ends of virion DNA. After nicking, the cohesive ends are separated by terminase; terminase bound to the left end of the DNA to be packaged then binds the empty protein shell, i.e., the prohead, and translocation of DNA into the prohead occurs. cosB, a site adjacent to cosN, is a terminase binding site. cosB facilitates the rate and fidelity of the cosN cleavage reaction by serving as an anchoring point for gpNu1, the small subunit of terminase. cosB is also crucial for the formation of a stable terminase-DNA complex, called complex I, formed after cosN cleavage. The role of complex I is to bind the prohead. Mutations in cosB affect both cosB functions, causing mild defects in cosN cleavage and severe packaging defects. The lethal cosB R3- R2- R1- mutation contains a transition mutation in each of the three gpNu1 binding sites of cosB. Pseudorevertants of lambda cosB R3- R2- R1- DNA contain suppressor mutations affecting gpNu1. Results of experiments that show that two such suppressors, Nu1ms1 and Nu1ms3, do not suppress the mild cosN cleavage defect caused by the cosB R3- R2- R1- mutation but strongly suppress the DNA packaging defect are presented. It is proposed that the suppressing terminases, unlike the wild-type enzyme, are able to assemble a stable complex I with cosB R3- R2- R1- DNA. Observations on the adenosine triphosphatase activities and protease susceptibilities of gpNu1 of the Nu1ms1 and Nu1ms3 terminases indicate that the conformation of gpNu1 is altered in the suppressing terminases.

Adenosine Triphosphatases↗

Metabolic and cardiovascular assessment in moderate obesity: effect of weight loss.

Metabolic and hemodynamic abnormalities have been separately described in obesity, and weight reduction is known to lead to some improvement in each. Our aim was to simultaneously assess metabolic and cardiovascular function in normotensive, normotolerant patients with moderate obesity (body mass index = 32.6 +/- 1.1 kg/m2) before and after weight loss. The obese were insulin resistant [37.4 +/- 4.8 mumol/min.kg FFM; P < 0.02 vs. 12 lean controls (50.6 +/- 2.6), on a euglycemic insulin clamp], secreted more insulin both in the fasting state and after oral glucose (70 +/- 10 vs. 48 +/- 6 nmol/mmol.L plasma glucose; P < 0.05), and had higher resting energy expenditure (4.62 +/- 0.18 vs. 4.00 +/- 0.23 kJ/min), systolic and mean blood pressure, stroke volume (87 +/- 8 vs. 67 +/- 4 mL/min; P = 0.05), and cardiac output. There was, however, no relationship between the metabolic and hemodynamic abnormalities. After a weight loss of 11 +/- 1 kg (approximately 15%), insulin sensitivity improved in proportion to the weight reduction, whereas insulin hypersecretion and high energy expenditure persisted. In contrast, all hemodynamic changes reverted to normal. We conclude that in moderate obesity, the metabolic and cardiovascular abnormalities are largely independent of one another; accordingly, weight loss affects them differentially. Partial weight normalization may provide sufficient cardiovascular protection.

Adult↗

MR cholangiography in the examination of patients with biliary-enteric anastomoses.

OBJECTIVE: The aim of our study was to determine the role of MR cholangiography in the noninvasive examination of patients with biliary-enteric anastomoses. SUBJECTS AND METHODS: Twenty-four patients (nine men and 15 women; mean age, 68.9 years old) with biliary-enteric anastomoses underwent MR cholangiography. We used a fat-suppressed three-dimensional turbo spin-echo sequence (3000/700 [TR/TE]; echo train length, 128) with no breath-hold, optimized with a 0.5-T magnet. Imaging studies were performed because of scheduled follow-up (five patients), persistent jaundice (six patients), cholangitis and abnormal liver function (eight patients), and a combination of transient jaundice, epigastric pain, and abnormal liver function (five patients). RESULTS: Image quality was graded from optimal to good in 21 (88%) of 24 cases and poor in three (13%) of 24 cases. The degree of bile duct dilatation was correctly assessed, with complete agreement between the two observers in all cases. MR cholangiography correctly showed bile duct irregularities in six of the eight patients with cholangitis (kappa = .59), anastomotic strictures in all 19 patients with strictures (kappa = .86), and 3- to 15-mm stones in nine of 10 patients (kappa = .95). A slight overestimation of the strictures occurred in four of the 19 cases with strictures. CONCLUSION: MR cholangiography is a reliable imaging technique for the examination of patients with biliary-enteric anastomoses.

Aged↗

Effect of insulin on systemic and renal handling of albumin in nondiabetic and NIDDM subjects.

Insulin resistance and hyperinsulinemia cluster with microalbuminuria in both diabetic and nondiabetic subjects, but the mechanism underlying this association is unknown. To test the hypothesis that insulin influences protein permeability, we measured the albumin transcapillary escape rate (TER) by the (131)I-labeled albumin technique in 12 healthy volunteers and 12 normoalbuminuric NIDDM patients (fasting plasma glucose, 10.9 +/- 1.3 mmol/l) during 4 h of isoglycemia with high (1.1 mU x min(-1) x kg(-1)) or, on a different day, low (0.1 mU x min(-1) x kg(-1)) insulin infusion. In both patients and control subjects, high insulin was associated with a 7% decrease in blood volume (P = 0.006) and a 6% decrease in diastolic blood pressure (P < 0.02), these two changes being related to one another (r = 0.56, P < 0.01). Basal albumin TER was similar in patients (8.4 +/- 0.5% x h(-1)) and control subjects (7.7 +/- 0.7% x h(-1)) and was not significantly changed by high insulin in either group (patients vs. control subjects, 7.3 +/- 0.9 vs. 6.2 +/- 0.4% x h(-1); NS vs. low insulin). In contrast, high insulin increased renal albumin excretion (from 3.6 +/- 0.8 to 5.4 +/- 1.1 microg/min, P < 0.01) and clearance rate (0.09 +/- 0.02 to 0.13 +/- 0.03 microl/min, P < 0.001) in patients but not in control subjects. To localize the effect of insulin along the nephron, we measured the urinary excretion of N-acetyl-beta-D-glucosaminidase (beta-NAG), released by the proximal tubule; retinol-binding protein (RBP), reabsorbed by the proximal tubule; and Tamm-Horsfall protein (THP) and epidermal growth factor (EGF), both secreted by the distal tubule. For both beta-NAG and RBP, but not EGF or THP, insulin enhanced urinary excretion (diabetics vs. controls: beta-NAG, 0.48 vs. -0.15 microU/min [P = 0.03]; RBP, 78 vs. -32 ng/min [P = 0.05]). In conclusion, physiological hyperinsulinemia does not affect systemic albumin permeability in healthy subjects or normoalbuminuric NIDDM patients. In contrast, in NIDDM patients, but not in healthy subjects, insulin increases the urinary excretion of albumin and protein markers of proximal tubular function. The significance of this finding for the pathogenesis of diabetic nephropathy remains to be established.

Adult↗

[Combined conventional magnetic resonance, magnetic resonance angiography, and magnetic resonance cholangiopancreatography in the diagnosis and staging of pancreatic carcinoma].

PURPOSE: This study was aimed to integrating MR CholangioPancreatography (MRCP) and MR Angiography (MRA) to conventional MR images in the diagnosis and resectability assessment of pancreatic adenocarcinoma. MATERIAL AND METHODS: Twenty-three consecutive patients with pancreatic adenocarcinoma (16 in the head and 7 in the body-tail region) were examined with MR. Conventional MR, 3D MRCP and venous and arterial MRA images were acquired to assess biliary and vascular involvement. Acquisition time never exceeded 40-45 minutes. The images were independently studied by two radiologists and the final reading was decided upon consensus among readers. Sixteen patients underwent surgery. RESULTS: The diagnosis was confirmed at surgery in 16 patients and at percutaneous biopsy in 7. Interreader agreement was considered high, with .83 interobserver variability. Pancreatic adenocarcinoma was found in all patients examined. Unresectability because of vascular involvement was correctly assessed in all patients but 1. Biliary obstruction was demonstrated in 13 patients, involving the biliary and pancreatic ducts in 9 and the biliary ducts only in 4. CONCLUSION: Technical advances now permit the extensive application of MRI to the study of abdominal conditions. The combination of MRI, MRCP and MRA can provide most of the information needed for the diagnosis and resectability assessment of pancreatic adenocarcinoma, which can otherwise be obtained only performing three different exams.

Adenocarcinoma↗

[MR cholangiopancreatography: technique, indications and clinical results].

INTRODUCTION: MR cholangiopancreatography (MRCP) is a new noninvasive imaging technique for the study of biliopancreatic disorders, providing projectional images of the biliary tree and pancreatic duct without any contrast agent. MATERIAL AND METHODS: We used different sequences, with both breath-hold and nonbreath-hold techniques, to acquire MRCP images, first based on GE and then on FSE sequences. FSE images provide higher SNR and are less susceptible to artifacts (metal objects, motion and blood flow artifacts). At the Department of Radiology of the University of Rome La Sapienza, we acquired MRCP images with non breath-hold, 3D fat-suppressed TSE sequences (TR = 3000-2000, TE 700, turbo factor 128) optimized on a .5T magnet with 15 mT/m gradients. No patient preparation or sedation was required, although antiperistaltic drugs and oral administration of tap water were preferred. Four hundred and thirty patients were examined, all of them with an indication to conventional cholangiography. RESULTS: MRCP depicted the whole common bile duct and the first-order intrahepatic branches in all the normal cases. Its accuracy in identifying biliary obstruction level and site was 100%, versus 94.6% in characterizing its cause. MRCP had 96.3% diagnostic accuracy in choledocholithiasis, with some false positives and false negatives caused by: 1) small stones missed on MIP reconstructions; 2) signal loss due to complete CBD obstruction by stones; 3) pneumobilia; 4) differential diagnosis between small stones and air bubbles. The main role of MRCP in benign strictures is to provide a detailed map of the biliary tract for better treatment planning. In particular, MRCP is extremely useful in hepaticojejunostomy patients, where ERC is not indicated because of postoperative anatomical changes. Both conventional MRI and MRCP are important in malignant strictures to identify the lesion and to characterize and stage it. Finally, MR pancreatography is very useful to follow up chronic pancreatitis patients because it shows Wirsung duct strictures and dilatations, intraductal filling defects and, in some cases, the communication between the pseudocyst and the pancreatic duct. CONCLUSIONS: MRCP combined with conventional MRI can completely replace CT and ERCP in bilio-pancreatic disorders.

Adult↗

MR cholangiopancreatography (MRCP) at 0.5 T: technique optimisation and preliminary results.

The aim of our study was to evaluate the feasibility of MR cholangiopancreatography (MRCP) at 0.5 T. To our knowledge no previous studies of MRCP have been performed at mid-field strength. Thirty-one patients with dilated biliary systems were examined with three-dimensional MRCP. All patients were studied with a 0.5 T superconducting magnet. A three-dimensional turbo spin-echo (TSE) sequence was acquired (TR = 5000 ms, TE = 244 ms, echo train length = 45; acquisition time = 14 min 10 s). Coronal images were post-processed with the MIP algorithm. Recently, the parameters have been optimised (TR = 3000 ms, TE = 700 ms, echo train length = 128), reducing the acquisition time to 3 min. Endoscopic retrograde cholangiopancreatography (ERCP) was performed in 26 cases; 5 patients underwent percutaneous transhepatic cholangiography PTC. MRCP and ERCP images were evaluated by an experienced radiologist and an endoscopist. MRCP of diagnostic quality was acquired in all patients. Choledocholithiasis was correctly evaluated by MRCP in 12 of 12 patients, compared with 11 correct diagnoses by ERCP. The presence and the level of the stricture were accurately shown in 16 of 16 patients with MRCP and in 13 of 16 patients with ERCP. The peripheral biliary tree above the obstruction and pancreatic duct were better evaluated by MRCP in all cases. In 3 of 3 patients who had undergone bilio-enteric surgery, a correct evaluation of the site of the anastomosis was possible with MRCP. It is concluded that MRCP performed at mid-field strength allows good visualisation of the dilated biliary system. Excellent results have been obtained on comparison with ERCP. MRCP performed at mid-field strength could have the same clinical value as high field strength MRCP.

Adult↗

Insulin decreases circulating vitamin E levels in humans.

Both hyperinsulinemia and free oxygen radicals have been implicated in the pathogenesis of atherosclerosis, but the relationship between insulin levels or insulin action and the oxidant/antioxidant balance has not been explored. We measured the effect of physiologic hyperinsulinemia on plasma concentrations of vitamin E, a major free radical scavenger molecule. Isoglycemic clamps (at an insulin infusion rate of 6 pmol . min-1 . kg-1) were performed in four groups of subjects: (1) 12 non-insulin-dependent diabetic (NIDDM) patients, (2) eight patients with essential hypertension, (3) 11 nondiabetic obese individuals, and (4) 12 healthy subjects. In 10 healthy volunteers, a time-control experiment was performed by replacing the insulin infusion with normal saline. Vitamin E and plasma lipid levels were determined at baseline and after 2 hours of insulin/saline infusion. Insulin sensitivity was reduced in diabetic, obese, and hypertensive groups in comparison to healthy controls, but fasting plasma vitamin E concentrations were similar in all groups. A consistent decrement in plasma vitamin E concentrations (averaging 12% of baseline, P < .0001) was observed in all subjects receiving insulin regardless of the level of insulin sensitivity, whereas no significant changes in plasma vitamin E were seen in subjects receiving saline infusion (P < .001 v insulin infusion groups). The insulin-induced decrement persisted in all study groups when plasma vitamin E concentrations were corrected for total serum cholesterol levels (-8.9% +/- 1.2% v -0.4 +/- 2.3% of saline controls, P = .0004) or serum low-density lipoprotein (LDL(-10.0% +/- 1.2% v -0.4% +/- 2.2%, P = .0002). We conclude that insulin infusion acutely depletes vitamin E in circulating lipids regardless of insulin resistance. This effect may represent a physiologic means of transferring vitamin E into cell membranes; alternatively, it might reflect a pro-oxidant action of insulin in vivo.

Adult↗

Radiology information and image management system: new approach to PACS with hypermedia capabilities of personal computers.

A system for archiving patient data and images was developed, installed, and evaluated in a radiology department. The system was developed with a relational database program for use with commercially available computers linked with an Ethernet network. The main options of the system are those of a conventional radiology information system: scheduling, registration, examination execution, reporting, archives and statistics, and system administration. However, the main feature of the system is the image archiving capability. Images are associated with patient records after capture by direct acquisition of the video signal or by scanning. Only relevant pathologic images are archived and a commonly employed compression algorithm is used, reducing the total memory requirement for each case to 200-600 kbytes. The diagnosis is still made by reading the original images. The low-resolution images stored in the system have an important role in teaching and consultation and as a first-line archive. Good results have been obtained with this system, which is used by medical and nonmedical staff without any special training.

Humans↗

Urinary excretion of Tamm-Horsfall protein in normotensive, normo-albuminuric type 1 diabetic patients.

The excretion rate of a marker of distal tubular function, Tamm-Horsfall protein (THP), has been measured in urine (micrograms/min) overnight, during orthostasis and during a glycaemic clamp (blood glucose concentration 7.0 mmol/l) with stable diuresis in 41 normotensive, normo-albuminuric type 1 diabetic patients. Eleven healthy subjects who were not clamped served as controls. A further 4 normo-albuminuric type 1 diabetic patients were rendered euglycaemic without a waterload. The excretion rate of THP overnight was similar in type 1 diabetic patients and normal subjects (26.1 vs. 23.5 micrograms/ml, p = NS). During the waterloaded euglycaemic clamp, THP increased significantly both in type 1 diabetic patients and control subjects (p < 0.001), but the increase was slightly greater in type 1 diabetic patients (67.2 vs. 38.4 micrograms/min, p = 0.05). Orthostasis did not increase the excretion rate of THP in either type 1 diabetic patients or in control subjects. In the 4 type 1 diabetic patients who were only clamped, the THP excretion rate increased less compared to the clamp plus waterload experiment (means: overnight 11.3 micrograms/min; clamp 22.5 micrograms/min). In Type 1 diabetes, overnight THP excretion was inversely correlated both with fasting blood glucose, HbA1 and sodium-lithium counter-transport activity (SLC). A direct relationship was present between urinary flow and the excretion rate of THP. In conclusion, this study shows that normotensive, normo-albuminuric type 1 diabetic patients present similar overnight excretion rates of THP compared to healthy controls and that the excretion rate of THP is unaffected by posture and increased during acute euglycaemia and waterload. The association between SLC and THP might suggest some relation between this putative marker of nephropathy and distal tubular function, but this finding needs confirmation and further study.

Adjuvants, Immunologic↗

Measures of tubular function in normoalbuminuric insulin-dependent diabetic patients and their relationship with sodium lithium countertransport activity.

The aim of this study was to assess the relationship between markers of tubular function, markers of glycaemic control and erythrocyte sodium-lithium countertransport activity (SLC) in 40 normotensive, normoalbuminuric insulin-dependent diabetic (IDDM) subjects and 11 normal control subjects. Nine IDDM subjects had SLC > 0.40 mmol lithium h-1 litre RBC-1. Glomerular filtration rate (GFR) and the excretion rate of retinol-binding protein (RBP), N-acetyl-beta-D-glucosaminidase (beta-NAG) and glucose were significantly higher in IDDM subjects compared to control subjects (Mann-Whitney test, p = 0.02, < 0.001, < 0.001 and < 0.001, respectively), whilst the two groups had similar SLC and TmPO4 levels. There was no significant relationship between SLC and the other variables in IDDM subjects, even when comparing IDDM subjects with normal and high SLC. beta-NAG excretion rate was correlated to urinary glucose (rs 0.47, p = 0.001) and, weakly, to the other markers of glycaemic control (fasting blood glucose rs = 0.31, p = 0.03, fructosamine rs 0.28, p = 0.04, HbA1 rs 0.27, p = 0.04). RBP excretion rate was correlated to the excretion rate of beta-NAG (rs 0.38; p = 0.007) and albumin (rs 0.45; p = 0.002); the excretion rates of beta-NAG and albumin were significantly associated (rs 0.37, p = 0.009). Diabetes duration did not correlate to any of the aforementioned variables. In this study, beta-NAG and RBP overnight excretion rates were higher in normoalbuminuric IDDM subjects compared to control subjects but no relationship was present between SLC and tubular function in IDDM patients without complications. Excretion rates of different proteins appear to be interrelated and, in IDDM, beta-NAG excretion is associated with glycaemic control.

Adolescent↗