1-23I-MIBG thyroid uptake: Implications for MIBG imaging of the heart

Background

123I-MIBG has been widely used in patients with heart failure and neurological disorders. The patients are pre-treated with Lugol’s oral solution or potassium perchlorate to prevent thyroid uptake of unlabeled 123I to limit the thyroid radiation exposure. However, despite the inhibition of the iodide pump, the thyroid is frequently visualized. The aim of this study was to study the pattern of thyroid uptake.

Methods

We reviewed the 123I-MIBG images of 57 patients studied in three different centers in Italy for cardiac (n = 42) or neurological (n = 15) indications. They were imaged at 15 minutes and 4 hours after injection and in all patients, the thyroid was included in the imaging field of view. In 2 of the 3 centers, the patients were pre-treated with Lugol’s oral solution and/or potassium perchlorate (group 1) but in the third center, they were not (group 2). The following imaging parameters were evaluated: heart-to-mediastinum ratio (H/M), thyroid-to-mediastinum ratio (T/M) at 4 hours, and tracer wash out from the heart (HWO) and from the thyroid (TWO).

Results

In the cardiac patients, the HWO was 22.98 ± 7.16% and TWO was 11.4 ± 11.86% (P < .0001). The TWO was 12.2 ± 13.1% in group 1 and 10.05 ± 8.97% in group 2 (P = NS). In the neurological patients the HWO was 26 ± 8.1% and the TWO was 20.32 ± 6.41 (P < .05). The difference in TWO was statistically significant (P < .01) between cardiac and neurological patients, whereas the HWO was not. The 4-hour H/M was 1.49 ± 0.23 in cardiac patients vs 1.4 ± 0.39 in neurological patients (P = NS). The 4-hour T/M was 1.33 ± 0.3 in cardiac patients vs 1.15 ± 0.13 in neurological patients (P < 0.05).

Conclusion

The thyroid visualization in MIBG imaging is likely an expression of thyroid sympathetic innervation. The differences in TWO and T/M ratio in cardiac and neurological patients probably express differences in thyroid dopaminergic receptors. Thus, pre-treatment with potassium perchlorate or Lugol’s solution may not be justified in patients undergoing 123I-MIBG imaging in whom the risk of side effects due to pre-treatment could be higher than the risk due to thyroid radiation exposure.

     

Can pulmonary hypertension be predicted by non-invasive approach? Echocardiographic and haemodynamic study

41 patients suffering from Chronic Obstructive Lung Disease (COLD) and 44 with Sarcoidosis were studied. Said patients underwent respiratory function tests, echocardiography (M.mode) to assess the right ventricular index ( RVI = diameter of the right ventricular cavity corrected by body surface) and the thickness of the right ventricular anterior wall ( RVAWT ); patients also underwent right heart haemodynamics (Swan-Ganz catheter). These data were further statistically studied by means of multiple regression in order to assess the eventuality of a non-invasive prediction of pulmonary artery mean pressure (PAP): variables taken into consideration were: age, body surface (BS), RVI , RVAWT , arterial oxygen pressure (PaO2), arterial carbon dioxide pressure (PaCO2) and PAP dependence according to each case group and the interaction of each group itself on the variables. RVI appeared to be the most reliable, in fact, when PaCO2 is also available, the standard error of estimation (SEE) was only 3.84 mmHg and the coefficient of determination was equal to 85.5% with a notable improvement when compared to results seen in previous studies. This behaviour was observed both in patients with early sarcoidosis and in COLD patients with mild pulmonary hypertension. This might be due to the fact that we took the right ventricle into consideration which inevitably feels the increase in pulmonary hypertension.     

Alterations of protein metabolism in acromegaly

PURPOSE OF REVIEW: Growth hormone is a powerful anabolic hormone necessary for normal growth, but its importance in maintaining the cellular and protein mass in adult life is still unclear. However, it is viewed as a drug capable of combating the tissue loss and some metabolic derangements of aging. Growth hormone excess causes acromegaly, a disease characterized by overgrowth of some tissues and multiple metabolic abnormalities. The purpose of this article is to review recent knowledge in acromegaly considering it as a model for clarifying aspects of growth hormone action on body composition, protein dynamics and molecular mechanisms in adult life. RECENT FINDINGS: Acromegaly induces well-documented changes in body fat (decreased), and bone density and water retention (increased), but there are less-clear changes in protein and body cell-mass accretion. Recent studies related insulin resistance to glucose metabolism to accelerated fat oxidation and described the reversibility of such alterations after surgical or pharmacologic therapy. Less attention was paid to changes in protein metabolism. Acromegalics are profoundly insulin-resistant to the antiproteolytic action of insulin, but amino acids are channelled towards protein synthesis because they are still normally spared from oxidation by insulin. This insulin resistance persists months after the surgical cure of acromegaly when glucose metabolism is already normalized. Recent studies suggested that increased use of fat for fuel by growth hormone may also promote protein anabolism and reduce amino acid oxidation. SUMMARY: Despite important advances in understanding molecular mechanisms in acromegaly, the specific effects on body cell and protein mass and the specific modulation of local protein dynamics remain poorly defined.     

Plasma ghrelin in anorexia, bulimia, and binge-eating disorder: relations with eating patterns and circulating concentrations of cortisol and thyroid hormones

The present study was designed to investigate the relations between plasma ghrelin concentrations, eating patterns, and circulating concentrations of cortisol and thyroid hormones in women with anorexia nervosa, bulimia nervosa, and binge-eating disorder. The patterns of disordered eating behavior were assessed using the Eating Attitudes Test (EAT-26) and the Bulimia Test-Revised (BULIT-R). In women with eating disorders, but not in healthy control women, plasma ghrelin concentrations were negatively correlated with body mass index (BMI) and plasma concentrations of thyreotropin (TSH), free T3 and free T4, and positively correlated with plasma concentrations of cortisol. The ghrelin concentrations of women with binge-eating and purging behavior were significantly lower than those of women with anorexia nervosa, restricting type, and there was a negative relation between the frequency and severity of binge-eating and purging behavior, as measured by the BULIT-R total score, and ghrelin concentrations. In a multivariate regression model controlling for the confounding effects of body mass index (BMI) and age, higher ghrelin concentrations were correlated with lower BULIT-R total scores. The results of this study did not confirm the hypothesis advanced in previous studies that ghrelin concentrations are higher in patients with binge-eating/purging forms of eating disorders. Based on these data, we suggest that, in women with eating disorders, ghrelin concentrations best reflect nutritional status rather than specific patterns of disordered eating behavior.     

Long-term outcome of right split in situ grafts in adults

In situ split liver transplants represent a technical progression from ex situ split procedures conceived to retrieve grafts for pediatric recipients. The transection line runs along the falciform ligament, so the main artery to the right graft is the right proper artery, whereas the left graft retains the main arterial axis with the celiac trunk. Although the major advantages are for pediatric recipients, due to the expanded pool of grafts available, for adult recipients the results of right split in situ grafts must be compared with whole grafts. We considered two groups of consecutive grafts transplanted since 1993 as first grafts: 20 of the former and 261 of the latter. Groups were comparable for donor gender, recipient age and gender, perfusion solution, ischemia time, and follow-up time, but not for donor age and for the number of arterial anastomoses. Although there were more major surgical complications in the former compared with the latter group (40% vs 25%), the only statistically significant difference was found in retransplantation rate for arterial complications (15% vs 2.2%). No statistical difference was observed in graft or patient actuarial survival rates at 1, 3, or 6 years after transplantation; for right split grafts these were 85%, 69%, and 69% and 95%, 79%, and 79%, respectively.     

Lymphotoxin alpha gene in Crohn's disease patients: absence of implication in the response to infliximab in a large cohort study

A haplotype in the lymphotoxin alpha (LTA) gene has been associated with a lack of response to infliximab in a small cohort of Crohn's disease (CD) patients. The present study aimed to confirm the implication of this haplotype in the response to infliximab in a larger cohort of Caucasian patients. The response to the first infusion with infliximab was evaluated in 214 Caucasian patients with either luminal (n=150) or fistulising (n=64) CD. Clinical response was based on the decrease in CD Activity Index (luminal) or on the evolution in the fistula discharge (fistulising). Biological response was assessed in 139 patients who had elevated C-reactive protein (CRP) before treatment and for whom CRP values were also available after treatment. A positive biological response was defined as a decrease in CRP of at least 25%. The patients were genotyped for six polymorphisms in the LTA gene. A positive clinical response was present in 65.4% of the patients and a positive biological response was observed in 80.6% of the patients. No association was found with any of the studied polymorphisms, nor with the previously published LTA haplotype and the response to infliximab. We could not confirm an association between the LTA locus and clinical or biological response to infliximab in a large cohort of CD patients.     

Anti-double-stranded DNA antibodies in the healthy elderly: Prevalence and characteristics

UsingCrithidia luciliae fluorescent assay a significant prevalence (7.6%;P<0.006) of anti-double-stranded DNA antibodies was found in a healthy old population. A negative enzyme-linked immunosorbent assay for anti-total histone antibodies excluded a false-positive reaction. Anti-double-stranded DNA antibodies in the aged differed from those found in patients with systemic lupus erythematosus and were characterized by a low titer (95.6% of cases), belonging to the IgA class alone (95.6%), no complement-fixing ability (100%), and negativity to Farr assay (100%). It is concluded that, in elderly subjects without signs and symptoms of disease, including systemic lupus erythematosus, such a peculiar anti-double-stranded DNA antibody may be detected.     

Histological and functional characteristics of peritoneal membrane in peritoneal sclerosis of PD patients

BACKGROUND: Function and structure of peritoneal membrane (PM) are impaired on peritoneal dialysis (PD). Peritoneal sclerosis is a common finding in peritoneal biopsies (PB) of PD patients. The aim of this study was to examine the impact of peritoneal sclerosis on peritoneal function and clinical parameters in PD patients submitted to peritoneal biopsy. METHODS: A PB was performed on 31 PD patients during catheter removal due to malfunction or after drop-out from treatment. For each patient PM transport was evaluated by the last peritoneal equilibration test before PB. Each daily glucose load was calculated. Tissue was formalin-embedded and stained for histological and immunohistochemical studies. RESULTS: Patients with submesothelial sclerosis and those with impairment of submesothelial basement membrane and subendothelial vascular membrane were submitted to a larger daily glucose load. Peritoneal sclerosis > 50 microns was more frequent in high transporters, who were exposed to larger daily glucose load compared to medium-high transporters. Mesothelial loss is correlated to peritoneal sclerosis and vascular injuries. CONCLUSIONS: Peritoneal sclerosis is not constant in PD patients: it is related to the loss of mesothelium integrity, to the daily glucose load of PD treatment and to vascular injuries, but apparently not to the presence of inflammatory infiltrate. It remains a matter of debate how much the peritoneal sclerosis modifies the function of PM and how new more biocompatible PD solutions could reduce PM injury.