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Biomedical subjects

R Caldara

Publications and source records attributed to R Caldara.

At least 19 recordsLinked to original sources
PubMed2006

Triple arterial reconstruction improves vascularization of whole pancreas for transplantation.

We assessed the effect on duodenal stump vascular supply of reconstruction of the gastroduodenal artery performed before pancreas transplantation. The median pancreas graft and patient survival times were 144 and 72 months for cases with or without gastrointestinal bleeding. Transmural blood flow values were significantly different between the donor duodenal stump and the recipient anastomosed jejunum (P < .01). The rate of gastrointestinal bleeding was lower in patients who received a pancreatic graft with back-table reconstruction of the gastroduodenal artery (P = .005).

Adult↗
PubMed2003

Face versus non-face object perception and the 'other-race' effect: a spatio-temporal event-related potential study.

OBJECTIVE: To investigate a modulation of the N170 face-sensitive component related to the perception of other-race (OR) and same-race (SR) faces, as well as differences in face and non-face object processing, by combining different methods of event-related potential (ERP) signal analysis. METHODS: Sixty-two channel ERPs were recorded in 12 Caucasian subjects presented with Caucasian and Asian faces along with non-face objects. Surface data were submitted to classical waveforms and ERP map topography analysis. Underlying brain sources were estimated with two inverse solutions (BESA and LORETA). RESULTS: The N170 face component was identical for both race faces. This component and its topography revealed a face specific pattern regardless of race. However, in this time period OR faces evoked significantly stronger medial occipital activity than SR faces. Moreover, in terms of maps, at around 170 ms face-specific activity significantly preceded non-face object activity by 25 ms. These ERP maps were followed by similar activation patterns across conditions around 190-300 ms, most likely reflecting the activation of visually derived semantic information. CONCLUSIONS: The N170 was not sensitive to the race of the faces. However, a possible pre-attentive process associated to the relatively stronger unfamiliarity for OR faces was found in medial occipital area. Moreover, our data provide further information on the time-course of face and non-face object processing.

Adult↗
PubMed2001

Prediction of the long-term metabolic success of the pancreatic graft function.

BACKGROUND: Strategies to prevent the return to the diabetic state for graft loss or failure or any other cause after pancreas transplantation require the identification of the subjects at risk. This study evaluated whether daily glucose, insulin, and c-peptide profiles and studies of insulin sensitivity and secretion after transplantation predict pancreatic graft failure. METHODS: Fifty-three subjects with type 1 diabetes with end-stage renal failure who received a combined pancreas and kidney transplant underwent the following procedures 1 year after transplantation: 1-day metabolic profiles, sampling every 2 hours for plasma glucose, serum insulin, and c-peptide (n=51); an intravenous glucose tolerance test (IVGTT) to evaluate insulin secretion (n=48); and an euglycemic insulin clamp to evaluate insulin sensitivity (M value, n=14). The recipients were then followed up to 8 years (mean follow-up 4.8+/-0.3 years) to evaluate the return to the diabetic state. RESULTS: Survival analysis showed that plasma glucose in the profiles and insulin secretion in IVGTT were strongly related to the risk of returning to the diabetic state. A cutoff value of mean daily plasma glucose >127 mg/dL, corresponding to the top quartile of the mean plasma glucose distribution in the profiles, predicted the return to the diabetic state within 4 years from transplantation with a 93% specificity and a 100% sensitivity. A cutoff value of insulin delta peak <32 microU/ml in the IVGTT predicted the return to the diabetic state within 4 years from transplantation with a 75% specificity and a 75% sensitivity. In contrast, the M value in the clamp was devoid of predictive value. CONCLUSIONS: This study indicates that the mean 24-h plasma glucose 1 year after transplantation is the strongest predictor of the return to the diabetic state. The risk is related to defects in insulin secretion and not to insulin resistance. Metabolic profiles can be used to screen the subjects at risk to strictly monitor the graft function and to investigate early determinants of graft failure.

Adult↗
PubMed2001

Alpha band power changes in unimanual and bimanual sequential movements, and during motor transitions.

OBJECTIVE: To investigate the cortical activation during execution of unimanual and bimanual synchronous and asynchronous finger sequences, as well as during transitions between those sequences. METHODS: Task-related power (TRPow) analysis of multichannel surface EEG was used to examine the regional oscillatory brain activity in the lower (7.8-9.8 Hz) and upper (10.8-11.8 Hz) alpha band. Unimanual to bimanual, bimanual to unimanual, and unimanual to unimanual transitions, prompted by visual cues, were studied in 10 right handed subjects. RESULTS: (1) Execution of unimanual and bimanual movements was accompanied by a bilateral activation over the central regions. (2) The 7.8-9.8 Hz TRPow decrease was more prominent for left and bimanual movements, suggesting sensitivity of the lower alpha band to task difficulty. (3) No difference in alpha oscillatory activity was found between bimanual synchronous and asynchronous sequences. (4) Transitions between motor sequences were invariably accompanied by a mesioparietal TRPow decrease in the lower alpha band. (5) This mesioparietal activation was contingent to the change of motor program, and could not be accounted for by the change of visual cue, or related attentional processes. CONCLUSION: The 7.8-9.8 Hz mesioparietal activation most likely reflects a posterior parietal motor command initiating transition between motor programs.

Adult↗
PubMed1999

Insulin secretory patterns and blood glucose homeostasis after islet allotransplantation in IDDM patients: comparison with segmental- or whole-pancreas transplanted patients through a long term longitudinal study.

IDDM patients undergoing islet, segmental pancreas or whole pancreas allotransplantation were studied at regular intervals after surgery (3-6 months, 1, 2, 3 and 4 years) to evaluate glycometabolic control (24 h metabolic profile, OGTT) and serum free insulin response to insulinogenic stimuli (arginine, IVGTT). Patients received the same immunosuppressive therapy, based on cyclosporin, steroids and azathioprine. Islet transplanted patients showed: 1) an early peak of insulin secretion after arginine, that was maintained up to 4 years; 2) an early, but low peak of insulin secretion after IVGTT, which was lost at 3 years, despite evidence that islets were still functioning (insulin independence with normal HbAlc levels); 3) a diabetic-like response to OGTT at 3 months, which improved at 2 years (IGT response); 4) fasting euglycemia with mild and reversible post-prandial hyperglycemia during the 24 h metabolic profile, which was maintained for up to 2 years. Insulin secretory patterns of islet transplanted patients were similar to segmental pancreas transplanted patients, and lower than whole pancreas transplanted patients. The reduced beta cell mass transplanted and the functional denervation of the transplanted islets seem to be the major determinants of this behaviour.

Adult↗
PubMed1999

Effects of pancreas transplantation on late complications of diabetes and metabolic effects of pancreas and islet transplantation.

Pancreas transplantation has become an accepted therapeutic approach to treat insulin-dependent diabetes mellitus, successfully restoring normoglycemia. In contrast, islet transplantation is still in the experimental phase, only a few operations having being performed world-wide. The aim of this review is to analyze the effects of pancreas transplantation on the late complications of diabetes and to report the endocrino-metabolic effects of pancreas and islet transplantation.

Blood Glucose↗
PubMed1998

Spontaneous hypoglycaemia after pancreas transplantation in Type 1 diabetes mellitus.

Hypoglycaemia is an important complication of insulin treatment in Type 1 diabetes mellitus (DM). Pancreas transplantation couples glucose sensing and insulin secretion, attaining a distinctive advantage over insulin treatment. We tested whether successful transplantation can avoid hypoglycaemia in Type 1 DM. Combined kidney and pancreas transplanted Type 1 DM who complied with good function criteria (KP-Tx, n = 55), and isolated kidney or liver transplanted non-diabetic subjects on the same immunosuppressive regimen (CON-Tx, n = 14), underwent 1-day metabolic profiles in the first 3 years after transplantation, sampling plasma glucose (PG) and pancreatic hormones every 2 hours. KP-Tx had lower PG than CON-Tx in the night and in the morning and higher insulin concentrations throughout the day. KP-Tx had lower PG nadirs than CON-Tx (4.40+/-0.05 vs 4.96+/-0.16 mmol l(-1), ANOVA p = 0.001). Nine per cent of KP-Tx had hypoglycaemic values (PG < or = 3.0 mmol l(-1)) in the profiles, both postprandial and postabsorptive, whereas none of CON-Tx did (p < 0.02). In conclusion, after pancreas transplantation, mild hypoglycaemia is frequent, although its clinical impact is limited. Compared to insulin treatment in Type 1 DM, pancreas transplantation improves but cannot eliminate hypoglycaemia.

Adult↗
PubMed1998

Mono-oligoclonal immunoglobulin abnormalities in diabetic patients after kidney transplantation: influence of simultaneous pancreas graft.

Monoclonal components (MC) are detected in as high as 30% of renal transplant recipients. Our aim was to evaluate the incidence, relevance and consequence of monoclonal components in patients with Type I (insulin-dependent) diabetes who received kidney (n = 22), kidney and whole pancreas (n = 41), kidney and segmental pancreas (n = 24) and kidney and islets (n = 12) transplants. Immuno-suppression was based on prophylactic anti-lymphocyte globulins, corticosteroids, azathioprine and cyclosporin in all patients; acute rejection was treated with steroids or anti-lymphocyte monoclonal immunoglobulin therapy (OKT3) or both. Serum immunofixation was carried out in all patients before transplantation and then after at 6 months and then yearly. Monoclonal components were detected in 81 of 99 patients (82%); 52 patients (52%) developed them within 6 months of transplantation, 15 (15%) between 6 and 12 months, with a peak prevalence at 1 year post-transplant (58%) and a decrease thereafter (10% at 9 years). Kidney recipients showed a lower incidence of monoclonal components when compared with those who received kidneys and segmental pancreases and those who received kidneys and whole pancreases. Monoclonal components were more often detected in patients who had previously experienced an acute renal rejection. Cytomegalovirus infection and acute rejection occurring in the same patient further increased the risk of developing monoclonal components, the development of which did not correlate with OKT3 treatment. A Post-transplant lymphoproliferative disorder was developed by two patients (2%), one with 5 and the other with 6 monoclonal components. In conclusion, diabetic patients receiving kidney and/or Pancreas transplantation, experiencing both cytomegalovirus infection and acute rejection, are at greatest risk of developing monoclonal components but they appear to be benign and transient; multiple band detection is a marker for the subsequent development of post-transplant lymphoproliferative disorder.

Adult↗
PubMed1995

Cephalic-phase insulin and glucagon release in normal subjects and in patients receiving pancreas transplantation.

The aim of the study was to evaluate whether the cephalic phase of insulin release is still present in patients submitted to simultaneous kidney and pancreas transplantation. Subjects were five kidney-pancreas-transplanted patients (group P) and five control (group C). The experimental protocol lasted 30 minutes, and blood samples were collected at 1-minute intervals. After a 20-minute period of steady-state fasting (premeal period), subjects received a palatable standard meal (pizza). Samples were collected over the subsequent 10 minutes (meal period). No evidence of an increase in serum free insulin, serum C-peptide, and plasma glucagon during food ingestion was observed in group P whereas the test was effective in eliciting cephalic-phase insulin and glucagon release in group C. Gastric inhibitory polypeptide and somatostatin did not show any variation during the test in both groups. In conclusion, the absence of cephalic-phase insulin and glucagon release in group P could be explained by denervation of the grafted pancreas. This early alteration could contribute to the impairment in glucose tolerance frequently observed in successfully pancreas-transplanted patients.

Adult↗
PubMed1994

Cholelithiasis and acromegaly: therapeutic strategies.

OBJECTIVE: The aims of this study were (i) to evaluate gall-bladder form and contents, (ii) to assess the prevalence of gallstones in acromegalic patients before octreotide treatment and the incidence of gallstone formation in patients with acromegaly during long-term (6-90 months, mean 44 months) octreotide treatment, and (iii) to test the efficacy of ursodeoxycholic acid in preventing and treating octreotide-induced cholelithiasis. DESIGN: Forty-nine patients (23 men and 26 women, aged 19-81 years) were studied by repeated gall-bladder ultrasonography performed at baseline and then every 6 months during octreotide therapy. All ultrasound scans were evaluated by the same radiologist. Statistical analysis was performed using the Chi-squared and regression analysis tests. RESULTS: Asymptomatic stones were recorded in 13/49 patients (26.5%) prior to octreotide treatment (the prevalence of cholelithiasis in the Italian population is 9.5% in men and 18.9% in women). During octreotide therapy gallstones developed in 10/36 patients (27.7%). No significant correlations with sex, age, body mass index, duration of the disease, daily dose and duration of octreotide therapy, altered gall-bladder form, family history of gallbladder stones, basal plasma values of cholesterol and triglycerides were found between the patients (10/36) who developed stones during octreotide treatment and the ones who did not (26/36). Fourteen patients (10 with newly developed stones and four with cholelithiasis diagnosed prior to octreotide) were put on ursodeoxycholic acid at the daily dose of 10 mg/kg. Gallstones completely disappeared in 6/14 patients (42.8%; five patients with newly developed stones and one with stones prior to octreotide therapy) after a mean of 30.8 months of ursodeoxycholic acid treatment. In addition, seven patients were treated with ursodeoxycholic acid at the preventive dose of 450 mg, administered as a once-a-day oral preparation in the evening. However, stones developed in one of these seven patients who was thereafter cured (gallstones completely disappeared) by the therapeutic dose of ursodeoxycholic acid of 10 mg/kg/day after 23 months of treatment. CONCLUSIONS: This study indicates that (i) acromegaly by itself is correlated with a high prevalence of gallbladder stones, (ii) the long-term treatment with octreotide increases the incidence of cholelithiasis, and (iii) ursodeoxycholic acid is useful in the treatment of gallstones in acromegalic patients but its prophylactic effect in patients on octreotide treatment requires further assessment.

Acromegaly↗
PubMed1994

Simultaneous kidney and pancreas transplantation at the San Raffaele Scientific Institute: clinical experience and results.

Pancreas and kidney transplantation is performed in uremic IDDM patients to cure end-stage renal failure and diabetes. Seventy-two simultaneous kidney-pancreas transplantations were performed at our Institution between July 1985 and November 1994. All transplants were performed using heart-beating cadaver donors. The first 25 patients received 26 segmental pancreas according to Dubernard (KPS), whereas the last 46 patients received a whole, bladder-drained pancrea according to Sollinger (KPW). Mean pancreas cold and warm ischemia times were 294 +/- 14 and 44 +/- 2 minutes, respectively, in the KPS group and 660 +/- 37 and 40 +/- 8 minutes, respectively, in the KPW group. Twelve (48%) KPS patients and 19 (41%) KPW patients had postoperative pancreas surgical complications: vascular thrombosis led to graft failure in 5 KPS patients (20%) and 2 KPW patients (4%) (p = 0.01). Pancreatic fistula, hemorrhagic complications, and duodenum-bladder leakage were the surgical complications observed more frequently. Six KPS patients (24%) and 8 KPW patients (17%) underwent reintervention as a consequence of surgical complications. Fifteen KPS patients (60%) and 30 KPW patients (65%) experienced an acute kidney rejection episode, which was steroid-resistant in 14 KPW and 2 KPS patients. The actuarial survival rates for simultaneous kidney-pancreas recipients at one and 4 years were 92% and 84%, respectively, for KPS recipients, and 95% and 88%, respectively, for KPW patients. Kidney actuarial survival rates at one and 4 years were 96% and 76% respectively, for group KPS, and 93% and 89%, respectively, for KPW patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗