TSH Response to TRH in Hemodialysis and CAPD Patients

The thyroid status was studied in 19 uremic patients (11 on HD and 8 on CAPD) and in a group of 17 healthy adult patients. In uremic patients T3 and T4 were significantly reduced (p < 0.001) and rT3 was increased (p < 0.001). The time course TSH response to TRH showed a lower peak response (in 5 patients it did not exceed 5 μU/ml) which on turn was also delayed (the peak was observed at 60 minutes in 63% of them). TSH concentrations in uremics were increased at 0 time (p < 0.02), lower at 20 minutes (p < 0.01) and increased at 120 minutes (p < 0.02). No difference existed between HD and CAPD. The thyroid response to TSH was normal as showed by a normal percent increase over basal values of T3 concentrations at 120 minutes. Uremic patients also showed a peak GH response at 20 minutes which was not observed in controls. The data exclude the existence on a primary form of hypothyroidism and point to the existence of hypothalamic-pituitary abnormalities, which should not be taken as indicative of secondary and/or tertiary hypothyroidism since FT4 values were normal in HD and increased in patients undergoing CAPD (p < 0.05) who on turn showed lower plasma albumin concentrations (p < 0.05).

Regulation of tumor growth by circulating full-length chromogranin A

Chromogranin A (CgA), a neuroendocrine secretory protein, and its fragments are present in variable amounts in the blood of normal subjects and cancer patients. We investigated whether circulating CgA has a regulatory function in tumor biology and progression. Systemic administration of full-length CgA, but not of fragments lacking the C-terminal region, could reduce tumor growth in murine models of fibrosarcoma, mammary adenocarcinoma, Lewis lung carcinoma, and primary and metastatic melanoma, with U-shaped dose-response curves. Tumor growth inhibition was associated with reduction of microvessel density and blood flow in neoplastic tissues. Neutralization of endogenous CgA with antibodies against its C-terminal region (residues 410-439) promoted tumor growth. Structure-function studies showed that the C-terminal region of CgA contains a bioactive site and that cleavage of this region causes a marked loss of anti-angiogenic and anti-tumor potency. Mechanistic studies showed that full-length CgA could induce, with a U-shaped dose-response curve, the production of protease nexin-1 in endothelial cells, a serine protease inhibitor endowed of anti-angiogenic activity. Gene silencing or neutralization of protease nexin-1 with specific antibodies abolished both anti-angiogenic and anti-tumor effects of CgA. These results suggest that circulating full-length CgA is an important inhibitor of angiogenesis and tumor growth, and that cleavage of its C-terminal region markedly reduces its activity. Pathophysiological changes in CgA blood levels and/or its fragmentation might regulate disease progression in cancer patients.

Modeling the Iatrogenic Pancreatic Cancer Risk After Islet Autotransplantation in Mouse

Iatrogenic pancreatic cancer metastasis after islet infusion is a potential risk of islet autotransplantation performed after pancreatectomy. To model this risk, islets and/or pancreatic exocrine clusters obtained from a genetically engineered mouse model for pancreatic ductal adenocarcinoma (the LSL-Kras^G12D/+ ;LSL-Trp53^R172H/+ ;Pdx-1-Cre, termed KPC mouse) were transplanted via the portal vein in syngeneic wild type (WT) severely diabetic recipients in the following treatment groups: group A (n = 11) received KPC exocrine clusters in volume equal to 250 islet equivalents (IEQs); group B (n = 12) received 250 WT IEQs mixed with KPC exocrine clusters (1:1 volume ratio); group C (n = 5) received 250 KPC IEQs, and group D (n = 7) received 250 WT IEQs. The incidence of hepatic metastasis was assessed by magnetic resonance imaging and histology over the 13 months of follow-up. Overall survival was not different in the four groups. No mice developed liver metastases during the follow-up. Two mice developed spontaneous tumors: a liver hepatocellular tumor in group A and a malignant lymphoma in group D. Islets and/or exocrine clusters obtained by KPC mouse, a model that develops pancreatic cancer with 100% penetrance, do not retain the same risk of tumor development when transplanted via the portal vein in a syngeneic diabetic recipient.

Short-term in vivo modifications of platelet NADPH oxidase 2 (NOX2) and prostaglandin F2α in HIV-1 patients on abacavir-based therapies

OBJECTIVES

The aim of the study was to investigate the in vivo effect of abacavir (ABC) on platelet oxidative stress.

METHODS

We performed a randomized pilot study including 39 HIV-1-infected patients, 17 on zidovudine/lamivudine (ZDV/3TC) and 22 on tenofovir/emtricitabine (TDF/FTC). Ten patients on ZDV/3TC and eight patients on TDF/FTC were randomly allocated to switching the nucleoside backbone to ABC/3TC. At baseline and after 6 months, platelet oxidative stress was assessed by platelet NADPH oxidase 2 (NOX2)-derived peptide (sNOX2-dp), a marker of NOX2 activation, and platelet prostaglandin F_2α (8-iso-PGF_2α ). Platelet activation was measured by soluble CD40L (sCD40L).

RESULTS

At baseline, no differences between ZDV/3TC or TDF/FTC recipients were found. After 6 months, patients switching from ZDV/3TC showed a decrease of sNOX2-dp (from 20.9±5.7 to 12.5±3.8 pg/ml, p=0.002) and 8-iso-PGF_2α (from 154.3±41.9 to 122.9±28.0 pmol/l, p=0.025). No effects on platelet oxidative stress biomarkers were observed in subjects from TDF/FTC, who showed a significant increase in blood glucose (p=0.043) and total cholesterol (p=0.027). ABC showed no effect on sCD40L levels in both groups.

CONCLUSIONS

ABC reduced platelet sNOX2-dp and 8-iso-PGF_2α in HIV-1 subjects switching from ZDV/3TC but not in those from TDF/FTC after 6 months. No changes in platelet activation were found in both groups.

Characterization of normal and scarred myocardium based on texture analysis of cardiac computed tomography images

An accurate detection of myocardial scar using Cardiac CT may have a strong clinical impact; however, the main drawback is the insufficient contrast to noise ratio of delayed iodine enhanced (DIE) CT images, which makes its accurate segmentation (manual as well as automatic) difficult. In this work, we investigate texture parameters applied on the different scans in order to obtain the scans and features that best differentiates normal from scarred myocardium. The experiments on 7 cases of myocarditis show the accuracy of the parameter energy in all scans, as well as the good performance of the angiographic scan (having higher spatial resolution) with different parameters for the segmentation propose. Moreover, the best performance was obtained on the baseline scan for the energy feature, with an accuracy of 94%.

Identification of High-Risk Patients After ST-Segment–Elevation Myocardial Infarction

Background—

The incidence of angiographic no reflow (NR) and microvascular obstruction (MVO) at cardiac magnetic resonance is significantly different. The aim of this study was to investigate the occurrence of NR and MVO in a cohort of consecutive patients with ST-segment–elevation myocardial infarction treated with primary percutaneous coronary interventions.

Methods and Results—

In this prospective study, 88 consecutive ST-segment–elevation myocardial infarction patients were enrolled within 12 hours from symptoms onset. All patients underwent cardiac magnetic resonance between 2 and 5 days after primary percutaneous coronary interventions. NR was defined as thrombolysis in myocardial infarction flow grade ≤2 and as myocardial blush grade <2. Presence of early or late MVO was assessed 4 and 10 to 15 minutes after gadolinium injection. Thirty-one patients (36%) had evidence of NR, whereas 58 (67%) had MVO. One NR patient did not have MVO. In contrast, NR was present in 30 of 58 MVO patients. MVO patients had higher troponin T peak ( P <0.0001), larger late gadolinium enhancement area ( P <0.0001), and lower left ventricular ejection fraction ( P <0.001) because of an increased end-systolic volume ( P =0.015). In contrast, patients with NR had higher troponin T peak ( P =0.006) but similar late gadolinium enhancement area ( P =0.24) compared with those without NR. Major cardiovascular adverse events–free survival was worse in patients with MVO ( P =0.014), although it was similar in patients with and without NR ( P =0.33). The independent predictors of major cardiovascular adverse events were MVO (hazard ratio, 3.418; P =0.046) and ischemic time (hazard ratio, 1.016; P <0.001). MVO was a strong predictor of target lesion revascularization occurrence ( P =0.017 for log-rank test).

Conclusions—

Compared with coronary angiography performed soon after recanalization of the culprit artery, cardiac magnetic resonance performed during index hospitalization provides better prognostic stratification of ST-segment–elevation myocardial infarction patients treated with primary percutaneous coronary interventions. Another novel finding of our study is a significantly increased rate of clinically driven target lesion revascularization in the index event culprit vessel in patients with MVO.

Role of the C-C chemokine receptor-2 in a murine model of injury-induced osteoarthritis

OBJECTIVE

We previously found in our embryonic studies that proper regulation of the chemokine CCL12 through its sole receptor CCR2, is critical for joint and growth plate development. In the present study, we examined the role of CCR2 in injury-induced-osteoarthritis (OA).

METHOD

We used a murine model of injury-induced-OA (destabilization of medial meniscus, DMM), and systemically blocked CCR2 using a specific antagonist (RS504393) at different times during disease progression. We examined joint degeneration by assessing cartilage (cartilage loss, chondrocyte hypertrophy, MMP-13 expression) and bone lesions (bone sclerosis, osteophytes formation) with or without the CCR2 antagonist. We also performed pain behavioral studies by assessing the weight distribution between the normal and arthritic hind paws using the IITS incapacitance meter.

RESULTS

Testing early vs delayed administration of the CCR2 antagonist demonstrated differential effects on joint damage. We found that OA changes in articular cartilage and bone were ameliorated by pharmacological CCR2 blockade, if given early in OA development: specifically, pharmacological targeting of CCR2 during the first 4 weeks (wks) following injury, reduced OA cartilage and bone damage, with less effectiveness with later treatments. Importantly, our pain-related behavioral studies showed that blockade of CCR2 signaling during early, 1-4 wks post-surgery or moderate, 4-8 wks post-surgery, OA was sufficient to decrease pain measures, with sustained improvement at later stages, after treatment was stopped.

CONCLUSIONS

Our data highlight the potential efficacy of antagonizing CCR2 at early stages to slow the progression of post-injury OA and, in addition, improve pain symptoms.

TWO NEW SINGLE-EXPOSURE, MULTI-DETECTOR NEUTRON SPECTROMETERS FOR RADIATION PROTECTION APPLICATIONS IN WORKPLACE MONITORING

This communication describes two new instruments, based on multiple active thermal neutron detectors arranged within a single moderator, that permit to unfold the neutron spectrum (from thermal to hundreds of MeV) and to determine the corresponding integral quantities with only one exposure. This makes them especially advantageous for neutron field characterisation and workplace monitoring in neutron-producing facilities. One of the devices has spherical geometry and nearly isotropic response, the other one has cylindrical symmetry and it is only sensitive to neutrons incident along the cylinder axis. In both cases, active detectors have been specifically developed looking for the criteria of miniaturisation, high sensitivity, linear response and good photon rejection. The calculated response matrix has been validated by experimental irradiations in neutron reference fields with a global uncertainty of 3%. The measurements performed in realistic neutron fields permitted to determine the neutron spectra and the integral quantities, in particular H*(10).

In vitro evaluation of prosthodontic impression on natural dentition: a comparison between traditional and digital techniques

OBJECTIVES

The aim of this in vitro study is to evaluate the marginal and internal fit of zirconia core crowns manufactured following different digital and traditional workflows.

METHODS

A 6° taper shoulder prepared abutment tooth was used to produce 20 zirconia core crowns using four different scanning techniques: scanned directly with the extraoral lab scanner, scanned with intraoral scanner, dental impressions using individual dental tray and polyether, dental casts from a polyether impressions. Marginal and internal fits were evaluated with digital photography and the silicone replica method.

RESULTS

Medium marginal gaps were 76,00 μm ± 28.9 for extraoral lab scanner, 80.50 μm ± 36,2 for intraoral scanner, 88.10 μm ± 34,8 for dental impression scan and 112,4 μm ± 37,2 for dental cast scan. Medium internal gaps were 23.20 μm ± 10,3 for extraoral lab scanner, 16.20 μm ± 8.3 for intraoral scanner, 27.20 μm ± 16.7 for dental impression scan and 30.20 μm ± 12.7 for dental cast scan.

CONCLUSION

Internal gap were extensively lower than 70 μm described in literature. Marginal fit was higher than ideal values for all the techniques but within the limit of clinical success. Intraoral scanners obtained the best results for internal gap.