The role of whole-body bone scintigraphy in a case of osteopetrosis

Male patient, 35 years old, with occasional mild intensity back pain. Lumbosacral spine radiography showed bone structure with increased density, diffusely and symmetrically, conferring to the vertebral bodies “bone-within-bone” aspect, suggesting osteopetrosis (OP). Whole-body bone scintigraphy showed abnormal uptake in proximal epiphysis of both the humeri, tibias and fibulas, distal epiphysis of the femurs and focal in the ribs suggesting old fractures. Conclusions: Nuclear Medicine may provide an important contribution as supporting diagnosis and extensive skeletal evaluation such as fractures and infection. Bone scintigraphy might also be used for baseline assessments, allowing longitudinal monitoring of the disease and patient follow-up

PEGylated versus Non-PEGylated pH-Sensitive Liposomes: New Insights from a Comparative Antitumor Activity Study

PEGylated liposomes are largely studied as long-circulating drug delivery systems. Nevertheless, the addition of PEG can result in reduced interactions between liposomes and cells, hindering liposomal internalization into target cells. The presence of PEG on the surface of pH-sensitive liposomes is not advantageous in terms of biodistribution and tumor uptake, raising the question of whether the indiscriminate use of PEG benefits the formulation. In this study, two doxorubicin-loaded pH-sensitive liposomal formulations, PEGylated (Lip2000-DOX) or non-PEGylated (Lip-DOX), were prepared and characterized. Overall, the PEGylated and non-PEGylated liposomes showed no differences in size or morphology in Cryo-TEM image analysis. Specifically, DLS analysis showed a mean diameter of 140 nm, PDI lower than 0.2, and zeta potential close to neutrality. Both formulations showed an EP higher than 90%. With respect to drug delivery, Lip-DOX had better cellular uptake than Lip2000-DOX, suggesting that the presence of PEG reduced the amount of intracellular DOX accumulation. The antitumor activities of free-DOX and both liposomal formulations were evaluated in 4T1 breast tumor-bearing BALB/c mice. The results showed that Lip-DOX was more effective in controlling tumor growth than other groups, inhibiting tumor growth by 60.4%. Histological lung analysis confirmed that none of the animals in the Lip-DOX group had metastatic foci. These results support that pH-sensitive liposomes have interesting antitumor properties and may produce important outcomes without PEG