Carbosilane Glycodendrimers for Anticancer Drug Delivery: Synthetic Route, Characterization, and Biological Effect of Glycodendrimer-Doxorubicin Complexes

The complexity of drug delivery mechanisms calls for the development of new transport system designs. Here, we report a robust synthetic procedure toward stable glycodendrimer (glyco-DDM) series bearing glucose, galactose, and oligo(ethylene glycol)-modified galactose peripheral units. In vitro cytotoxicity assays showed exceptional biocompatibility of the glyco-DDMs. To demonstrate applicability in drug delivery, the anticancer agent doxorubicin (DOX) was encapsulated in the glyco-DDM structure. The anticancer activity of the resulting glyco-DDM/DOX complexes was evaluated on the noncancerous (BJ) and cancerous (MCF-7 and A2780) cell lines, revealing their promising generation- and concentration-dependent effect. The glyco-DDM/DOX complexes show gradual and pH-dependent DOX release profiles. Fluorescence spectra elucidated the encapsulation process. Confocal fluorescence microscopy demonstrated preferential cancer cell internalization of the glyco-DDM/DOX complexes. The conclusions were supported by computer modeling. Overall, our results are consistent with the assumption that novel glyco-DDMs and their drug complexes are very promising in drug delivery and related applications.

[Conservative treatment of acetabular fractures: epidemiology and medium-term clinical and radiological results]

PURPOSE OF THE STUDY

The vast majority of studies on fractures of the acetabulum are concerned with surgical treatment. All displaced fractures are presented as surgically treated. The purpose of this study was to evaluate the results of surgical and conservative treatment of patients with acetabular fractures in relation to the degree of fracture displacement.

MATERIAL AND METHODS

We analysed 140 fractures of the acetabulum treated in our institution by different methods between 2009 and 2013. In addition to the use of Letournel´s classification, we allocated each fracture to one of six groups: 1. Sixty displaced fractures treated surgically, 2. Twenty three fractures with a displacement of more than 6 mm, 3. Eighteen slightly displaced fractures (2-3 mm in the acetabular roof or 4-5 mm in other parts of the acetabulum), 4. Twenty non-displaced fractures, 5. Six pelvic fractures involving the acetabulum and 6. Thirteen fractures of old people, mostly displaced but not examined by CT. Groups 2 to 6 were treated conservatively. In all patients, demographic and epidemiologic factors were analysed in relation to the patient's group assignment. In 107 patients, hip function was assessed using the Matta clinical grading system at a minimum follow-up of 12 months (average 3.16 years). Radiological status, time of admission, start of weight-bearing after the accident, working ability, mortality and complications were also evaluated.

RESULTS

Non-displaced fractures were often associated with serious injury or polytrauma in 20 patients; not all of them had excellent functional outcome. (mean score, 17.25). Excluding two patients who developed avascular necrosis, fourteen slightly displaced fractures had a fixal score of 16.92. Sixteen patients with displaced fractures were managed conservatively due to their poor medical condition and other circumstances. Their functional outcome (mean score, 15.25) was significantly worse than that of the patients with non-displaced fractures (p=0.02) and worse than the outcome in patients with slightly displaced fractures, but the difference was not significant (p=0.32). No occurrence of accelerated post-traumatic arthritis was observed in these groups. The mean clinical score of 14.80 and 60% of excellent and good results were achieved in surgically treated patients. Eight of them were treated by primary hip arthroplasty and osteosynthesis. A total of 11 patients required total hip arthroplasty because of post-traumatic osteoarthritis, but only one from the group of slightly displaced fractures, all others from the group of surgically treated patients.

DISCUSSION

Displaced fractures of the acetabulum are best treated by open reduction and internal fixation. The type of fracture and the quality of reduction influence the functional outcome. There are a few studies reporting long-term outcomes in conservatively treated acetabular fractures. Although conservative treatment continues to be the mainstay of treatment in most centres in the developing countries, it is obvious that not all of acetabular fractures can or must be treated surgically or identically. We found that, in many cases, surgery was too dangerous for the patient and his/her medical condition or that the result of surgery was doubtful, mostly because of a late presentation. In some cases, primary hip arthroplasty is a solution. Secondary total hip replacement is technically more demanding and has a higher rate of failure.

CONCLUSIONS

Conservative treatment is the method of choice for the treatment of non-displaced acetabular fractures. Excellent or very good results can also be expected in slightly displaced fractures if acetabular roof involvement is minor. In displaced fractures, if the result of surgery is doubtful under various circumstances or if high-risk medical conditions are present in the patient, conservative treatment can be the method of choice with satisfying results. Key words: acetabular fractures, conservative treatment, degree of displacement, epidemiology of acetabular fractures.

[Pedicle screw fixation of thoracic spine fractures]

PURPOSE OF THE STUDY

Fractures of the thoracic spine involve injury at the levels of Th2 to Th10. Because of pedicle morphology, pedicle screw fixation is a demanding procedure. However, evidence on the reliability and efficiency of this technique has recently been provided by several studies. The aim of this study was to analyse a group of patients with thoracic spine fractures treated by pedicle screw fixation and to evaluate treatment outcomes.

MATERIAL AND METHODS

A total number of 33 patients treated by pedicle screw fixation for thoracic spine fractures between January 2007 and December 2011 were enrolled in this retrospective study. The mean age was 39.7 ± 16.7 years. The evaluation included demographic data, mechanism of injury, associated injuries, neurological status, fracture type (AO classification), levels of the fractured vertebrae, injury-surgery interval, type and duration of surgery, type and length of pedicle screw fixation and complications. The position of pedicular screws in relation to the pedicle walls and correction of kyphotic deformity were assessed on post-operative CT scans.

RESULT

Of the 33 patients, 24 had associated injuries (72.7%), 22 had thorax injury (66.7%) and 17 had neurological deficit (51.5%). The most frequent spinal fracture type was type B2, 15 (45.5%); followed by type C, nine (33.3%); and type B1, five (15.1%). The mean injury-to-surgery interval was 5.2 ± 4.3 days. The mean operative time was 210 ± 56 min. The most frequently used configuration of pedicle screw fixation involving two segments above and two below the fracture level was used in 20 cases (58.8%). The position of 149 out of 282 pedicle screws (52.8%) was evaluated on post-operative CT scans as follows: 98 % of the pedicle screws were placed in acceptable positions, 76% were placed completely within pedicle borders. The mean pre-operative Cobb angle was 18.7° ± 8.2°, the mean post-operative Cobb angle was 9.3 ± 3.4°. Six intraoperative and three post-operative complications occurred. During follow-up no instrumentation failure or apparent loss of correction was recorded.

DISCUSSION

Early stabilisation of thoracic spine fractures reduces the risk of complications, shortens the hospital stay and allows for faster recovery of patients. Early thoracic spine stabilisation is most beneficial in patients with a high ISS (Injury Severity Score). In the case of small-sized pedicles there is the possibility of pedicle screw insertion via an extrapedicular or parapedicular trajectory. Recommended pedicle screw fixation is two levels above and two levels below the fracture level.

CONCLUSIONS

Pedicle screw fixation of thoracic spine fractures is a safe therapeutic method with a low risk of complications. It facilitates effective reduction and stable fixation with a low risk of secondary displacement and implant failure. Key words:transpedicular stabilisation, thoracic spine, fracture, pedicle screws.