PEGylation of NIR Cd0.3Pb0.7S aqueous quantum dots for stabilization and reduction of nonspecific binding to cells.

Cd0.3Pb0.7S (CdPbS) aqueous quantum dots (AQDs) made with 3-mercaptoproprionic acid (MPA) as a ligand have the advantages of emitting near-infrared light, well above 800 nm, that completely circumvents interference from tissue autofluorescence and have significant amounts of ligands for bioconjugation. However, retaining the right amount of MPA became a challenge when using CdPbS AQDs for bioimaging because retaining too much MPA could lead to significant nonspecific staining in cell imaging while insufficient MPA could cause AQDs instability in biological systems. Here we examined PEGylation (i.e. chemically linking amine-functionalized polyethylene glycol (PEG)) to modify MPA on the AQDs surface to improve AQDs stability and reduce nonspecific staining. In addition, for conjugation with antibodies, a bifunctional PEG with a carboxyl functionality was used to permit chemical linkage of a PEG to an antibody on the other end. It was found that performing PEGylation at the thiol concentration where the zeta potential becomes saturated stabilized the CdPbS AQDs suspension and reduced nonspecific binding to cells. Furthermore, with the bifunctional PEG, the CdPbS AQDs were conjugated with antibodies and the AQD-Ab conjugates were shown to stain cancer cells specifically against normal cells with a signal-to-noise ratio of 8.

Early developed ASD (adjacent segmental disease) in patients after surgical treatment of the spine due to cancer metastases.

BACKGROUND: The causes of ASD are still relatively unknown. Correlation between clinical status of patients and radiological MRI findings is of primary importance. The radiological classifications proposed by Pfirmann and Oner are most commonly used to assess intradiscal degenerative changes. The aim of the study was to assess the influence of the extension of spine fixation on the risk of developing ASD in a short time after surgery. METHODS: A total of 332 patients with spinal tumors were treated in our hospital between 2010 and 2013. Of these patients, 287 underwent surgeries. A follow-up MRI examination was performed 12 months after surgical treatment. The study population comprised of 194 patients. Among metastases, breast cancer was predominant (29%); neurological deficits were detected in 76 patients. Metastases were seen in the thoracic (45%) and lumbar (30%) spine; in 25% of cases, they were of multisegmental character. Pathological fractures concerned 88% of the patients. Statistical calculations were made using the χ2 test. Statistical analysis was done using the Statistica v. 10 software. A p value <0.05 was accepted as statistically significant. The study population was divided on seven groups according to applied treatment. RESULTS: Clinical signs of ASD were noted in only seven patients. Two patients had symptoms of nerve root irritation in the lumbar spine. Twenty-two patients (11%) were diagnosed with ASD according to the MRI classifications by Oner, Rijt, and Ramos, while the more sensitive Pfirmann classification allowed to detect the disease in 46 patients (24%). Healthy or almost healthy discs of Oner type I correlated with the criteria of Pfirmann types II and III. The percentage of the incidence of ASD diagnosed 1 year after the surgery using the Pfirmann classifications was significantly higher than diagnosed according to the clinical examination. CONCLUSIONS: The incidence of ASD in patients after spine surgeries due to cancer metastases does not differ between the study groups. ASD detectability based on clinical signs is significantly lower than ASD detectability based on MR images according to the system by Pfirrmann et.al. ASD risk increase among patients with multilevel fixation.

"Quality of life of patients after surgical treatment of cervical spine metastases".

BACKGROUND: Metastases of malignant neoplasms to the cervical spine are relatively rare. The most common symptom of metastatic disease is pain. Symptoms associated with roots damage or spinal cord compression indicate locally advanced disease. In a large number of patients, surgical treatment brings benefits such as pain reduction and improvement of the quality of life. Pain intensity, neurological status, and quality of patients' lives are measured with the VAS, Frankel, and Karnofsky scales. METHODS: Symptoms of the disease, morphology of the metastasis and treatment outcomes were evaluated in 57 patients treated surgically because of metastases to the cervical spine over the period 2010-2014 in Brzozów. The morphology of the metastases was assessed on the basis of CT and MR examinations. Pre- and postoperative functional status of the patients was evaluated using Karnofsky scale. The intensity of pain was assessed with VAS and the neurological status was evaluated by using Frankel's grades. Anterior approach was employed in 16 patients, posterior approach in 30 patients, and postero-anterior approach in 11 patients. The inter-group differences were evaluated using the U Mann-Whitney and Wilcoxon Matched Pairs test. All statistical analyses were performed by using Statistica 10. A value of P < 0.05 was considered statistically significant. RESULTS: The majority of patients suffered from pain associated with instability of the spine. Multi-level metastases were noted in 40 patients, while in 17 patients 1 vertebra was involved. In 51 patients the metastases caused pathological fractures of the vertebrae. The most common neurological complications was observed in patients with multi-level tumors and with pedicles involvement. After surgery patients functional status improved and pain intensity decreased. The best results (statistically significant) were observed in patients operated with anterolateral approach. Complications were scarce. Two patients required reoperation due to infection. CONCLUSIONS: Surgical treatment of metastases to the cervical spine gives good outcomes and it ought to be a treatment of choice. Proper and multifaceted qualification of the patients for different treatments is of vital importance.