In Vivo Imaging of Local Inflammation: Monitoring LPS-Induced CD80/CD86 Upregulation by PET

Purpose

The co-stimulatory molecules CD80 and CD86 are upregulated on activated antigen-presenting cells (APC). We investigated whether local APC activation, induced by subcutaneous (s.c.) inoculation of lipopolysaccharides (LPS), can be imaged by positron emission tomography (PET) with CD80/CD86-targeting ⁶⁴Cu-labelled abatacept.

Procedures

Mice were inoculated s.c. with extracellular-matrix gel containing either LPS or vehicle (PBS). Immune cell populations were analysed by flow cytometry and marker expression by RT-qPCR. ⁶⁴Cu-NODAGA-abatacept distribution was analysed using PET/CT and ex vivo biodistribution.

Results

The number of CD80⁺ and CD86⁺ immune cells at the LPS inoculation site significantly increased a few days after inoculation. CD68 and CD86 expression were higher at the LPS than the PBS inoculation site, and CD80 was only increased at the LPS inoculation site. CTLA-4 was highest 10 days after LPS inoculation, when CD80/CD86 decreased again. A few days after inoculation, ⁶⁴Cu-NODAGA-abatacept distribution to the inoculation site was significantly higher for LPS than PBS (4.2-fold). Co-administration of unlabelled abatacept or human immunoglobulin reduced tracer uptake. The latter reduced the number of CD86⁺ immune cells at the LPS inoculation site.

Conclusions

CD80 and CD86 are upregulated in an LPS-induced local inflammation, indicating invasion of activated APCs. ⁶⁴Cu-NODAGA-abatacept PET allowed following APC activation over time.

     

Single molecule high-resolution colocalization of Cy3 and Cy5 attached to macromolecules measures intramolecular distances through time

Here we present a technique called single-molecule high-resolution colocalization (SHREC) of fluorescent dyes that allows the measurement of interfluorophore distances in macromolecules and macromolecular complexes with better than 10-nm resolution. By using two chromatically differing fluorescent molecules as probes, we are able to circumvent the Rayleigh criterion and measure distances much smaller than 250 nm. The probes are imaged separately and localized individually with high precision. The registration between the two imaging channels is measured by using fiduciary markers, and the centers of the two probes are mapped onto the same space. Multiple measurements can be made before the fluorophores photobleach, allowing intramolecular and intermolecular distances to be tracked through time. This technique's lower resolution limit lies at the upper resolution limit of single molecule FRET (smFRET) microscopy. The instrumentation and fluorophores used for SHREC can also be used for smFRET, allowing the two types of measurements to be made interchangeably, covering a wide range of interfluorophore distances. A dual-labeled duplex DNA molecule (30 bp) was used as a 10-nm molecular ruler to confirm the validity of the method. We also used SHREC to study the motion of myosin V. We directly observed myosin V's alternating heads while it walked hand-over-hand along an actin filament.     

Aerobic exercise improves oxidant-antioxidant balance in patients with rheumatoid arthritis

[Purpose] Although oxidative stress is known to be present in rheumatoid arthritis (RA), the effects of exercise on oxidative parameters are unknown. The aim of this study was to investigate the effects of acute aerobic exercise on serum oxidant and antioxidant levels in patients with RA. [Subjects and Methods] Sixteen patients with RA and 10 age-matched healthy volunteers participated in this study. All participants wore polar telemeters and walked on a treadmill for 30 minutes at a speed eliciting 60–75% of maximal heart rates. Blood samples were obtained before, immediately and 24 hours after exercise and malondialdehyde (MDA) and total sulfhydrile group (RSH) levels were measured. [Results] Both groups had similar heart rates during the test but the treadmill speed of the RA patients was significantly lower than that of the healthy volunteers. Serum MDA levels were lower than in both groups immediately after exercise, with greater decrements in the RA patients than controls. MDA levels returned to baseline 24 hours after the exercise only in the controls; they remained low in the RA patients. There was a slight increase in serum RSH levels after exercise compared to baseline in both groups. [Conclusion] Moderate intensity treadmill exercise did not have any adverse effect on the oxidant-antioxidant balance. The results suggest that such an exercise may be safely added to the rehabilitation program of RA for additional antioxidant effects. Morever, this antioxidant environment is maintained longer in RA patients.Key words: Aerobic exercise, Oxidative status, Rheumatoid arthritis     

Pattern of primary tumors and tumor-like lesions of bone in children: retrospective survey of biopsy results

Background: Although primary bone tumors are relatively uncommon, they constitute the most important tumors in patients less than 20 years. We aimed to determine the frequencies of primary bone tumors and tumor-like lesions of bone and the anatomical sites of their occurrence. Methods: A retrospective review of histopathology reports of all bone specimens received in a private pathology laboratory in Istanbul between 2009 and 2015. Results: A total of 57 patients (aged 5 to 18 years) with a mean of 13.12 years were studied. Thirty five patients (61.4%) were males and 22 (38.6%) were females. Fifty five (94.4%) of the tumors were benign. Osteochondroma was the commonest tumor accounting for 31 cases (54.3%) followed by osteoid osteoma, 9 cases (15.7%). Chondrosarcoma observed in two patients and Ewing sarcoma in one patient as malignant tumors. Of the 57 bone tumors 13 (22.8%) occurred in the upper extremities, while 44 (77.2%) were in the lower extremities. Proximal humerus was the most commonly involved site in upper extremity tumors, with osteochondromas representing the most frequent type of tumor (4 patients; 7%). In the lower extremities again osteochondromas were the most common type of tumor (8 cases, 14%), with the femur being the most common site of involvement (18 patients, 31.5%). Of the patients with tumor-like lesions; four patients had fibrous dysplasia, 4 patients had non-ossified fibromas, 4 patients had simple bone cysts and 3 had aneurismal bone cyst. Conclusion: This study showed that primary bone tumors were mainly benign, settled predominantly in the lower extremities mostly in the femur with a male preponderance. Osteochondroma was the most common benign bone tumor. We didn’t observed osteosarcoma, which is the most frequent malignant bone tumor.     

ROHHAD Syndrome: Reasons for Diagnostic Difficulties in Obesity

A very rare syndrome of rapid-onset obesity with hypoventilation, hypothalamic dysfunction and autonomic dysregulation (ROHHAD) has been recently described as causing morbidity due to hypothalamic dysfunction and respiratory arrest. Its prognosis is poor and often cardiac arrest occurs due to alveolar hypoventilation. This disorder can mimic genetic obesity syndromes and several endocrine disorders. We present a 13-year-old female patient who was reported to be healthy until the age of 3 years. She was admitted to our emergency department, presenting with respiratory distress. Features matching ROHHAD syndrome such as rapid-onset obesity, alveolar hypoventilation, central hypothyroidism, hyperprolactinemia, Raynaud phenomenon and hypothalamic hypernatremia were detected in the patient. In addition to these features, the patient was found to have hypergonadotropic hypogonadism and megaloblastic anemia. Because of its high mortality and morbidity, the possibility of ROHHAD syndrome needs to be considered in all pediatric cases of early- and rapid-onset obesity associated with hypothalamic-pituitary endocrine dysfunction.