Simvastatin loaded chitosan guided bone regeneration membranes stimulate bone healing

BACKGROUND AND OBJECTIVE

Electrospun chitosan membranes (ESCM) modified with short-chain fatty acids have the ability to control the release of simvastatin (SMV), an anti-cholesterol drug with osteogenic potential, for guided bone regeneration (GBR) applications. This study evaluated in vivo osteogenic effects of rapid short release of SMV (4 weeks) vs long sustained release (8 weeks) from acetic anhydride (AA)-and hexanoic anhydride (HA)-modified ESCMs, respectively.

METHODS

AA ESCMs loaded with 10 or 50 µg SMV and HA ESCMs loaded with 50 µg SMV were evaluated for biocompatibility and bone formation at 4 and 8 weeks, in 5 mm critical size rat calvarial defects, using histological evaluation and micro-CT analysis.

RESULTS

No severe inflammatory response was noticed around the ESCMs. Less hydrophobic AA membranes showed signs of resorption by week 4 and were almost completely resorbed by week 8 whereas the more hydrophobic HA membranes resorbed slowly, remaining intact over 8 weeks. In micro-CT analysis, 10 µg SMV-loaded AA membranes did not show significant bone formation as compared to non-loaded AA membranes at either evaluation time points. 50 µg SMV-loaded AA membranes stimulated significantly more bone formation than non-loaded AA membranes by week 4 (%bone = 31.0 ± 5.9% (AA50) vs 18.5 ± 13.7% (AA0)) but showed no difference at week 8. HA membranes with 50 µg SMV showed significantly more bone formation as compared to corresponding non-loaded membranes by week 8 (%bone = 61.7 ± 8.9% (HA50) vs 33.9 ± 29.7% (HA0)), though such an effect was not significant at week 4.

CONCLUSION

These results indicate that modified ESCMs may be used to control the release of SMV and promote bone healing in GBR applications.

The incidence and pattern of maxillofacial injuries in helmeted versus non-helmeted motorcycle accident patients

PURPOSE

The aim of this study was to investigate the difference in incidence and pattern of bony and soft tissue injuries sustained by helmeted versus non-helmeted motorcycle accident patients.

MATERIALS AND METHODS

The medical records of motorcycle accident patients over a 10-year period were reviewed. Basic demographic data including age, gender, and Injury Severity Score (ISS) were collected. The patients were separated into 2 groups based on helmet use. For each group, the incidence of specific maxillofacial injuries (based on the International Classification of Diseases, Ninth Revision) was tallied. Statistical analysis was performed with the Fisher exact test.

RESULTS

A total of 717 patients were included in the study: 598 patients (mean age, 41.6 years; male gender, 90.8%; ISS, 18.2) were in the helmeted group and 119 patients (mean age, 40.8 years; male gender, 90.8%; ISS, 19.5) were in the non-helmeted group. Among the helmeted riders, 26.1% (n=156) sustained a maxillofacial injury, and among the non-helmeted riders, 45.4% (n=54) sustained a maxillofacial injury (P=.0001). The non-helmeted riders also had a significantly higher incidence of malar and maxillary fractures (P=.040), orbital fractures (P=.044), and soft tissue contusions and abrasions (P=.031).

CONCLUSIONS

The results of this study suggest that not only do helmets protect against facial injuries in totality, they appear to be more effective at preventing midfacial fractures when compared with mandible fractures.

Effects of pool isolation on trophic ecology of fishes in a highland stream

The objective of this study was to examine the effects of pool isolation on fish diet and to answer three questions: Were food resources different or reduced in isolated compared with connected pools? Were fishes more selective and did they increase resource partitioning in isolated pools? Would individuals exhibit increased gastrointestinal tract (GIT) length in isolation to aid nutrient absorption? Benthic macroinvertebrate density and richness were significantly lower in isolated pools compared with connected pools; fishes became more selective and partitioned resources more in isolated pools and all three species showed an increase in GIT length in isolated pools compared with connected pools. With a changing climate predicted to increase intermittency within headwater streams, the results show that these fishes have the adaptive ability to respond and continue to survive.

Spatiotemporal dispersion and wave envelopes with relativistic and pseudorelativistic characteristics

A generic nonparaxial model for pulse envelopes is presented. Classic Schrödinger-type descriptions of wave propagation have their origins in slowly-varying envelopes combined with a Galilean boost to the local time frame. By abandoning these two simplifications, a picture of pulse evolution emerges in which frame-of-reference considerations and space-time transformations take center stage. A wide range of effects, analogous to those in special relativity, then follows for both linear and nonlinear systems. Explicit demonstration is presented through exact bright and dark soliton pulse solutions.

Helmholtz-Manakov solitons

A different spatial soliton-bearing wave equation is introduced, the Helmholtz-Manakov (HM) equation, for describing the evolution of broad multicomponent self-trapped beams in Kerr-type media. By omitting the slowly varying envelope approximation, the HM equation can describe accurately vector solitons propagating and interacting at arbitrarily large angles with respect to the reference direction. The HM equation is solved using Hirota's method, yielding four different classes of Helmholtz soliton that are vector generalizations of their scalar counterparts. General and particular forms of the three invariants of the HM system are also reported.

Fresnel diffraction and fractal patterns from polygonal apertures

Two compact analytical descriptions of Fresnel diffraction patterns from polygonal apertures under uniform illumination are detailed. In particular, a simple expression for the diffracted field from constituent edges is derived. These results have fundamental importance as well as specific applications, and they promise new physical insights into diffraction-related phenomena. The usefulness of the formulations is illuminated in the context of a virtual source theory that accounts for two transverse dimensions. This application permits calculation of fractal unstable-resonator modes of arbitrary order and unprecedented accuracy.

Thrombosis in children receiving L-asparaginase. Determining patients at risk

PURPOSE

A prospective study of coagulation in 15 children who received L-asparaginase, vincristine, or prednisone plus or minus an anthracycline as part of a treatment program for leukemia or leukemia-lymphoma syndrome was conducted.

PATIENTS AND METHODS

One patient developed a central nervous system thrombosis.

RESULTS

The inhibitors of coagulation, including antithrombin-III, protein C, protein S, and plasminogen, were decreased in many individuals, but were not significantly different in the patient who had experienced the thrombotic event. Platelet aggregations to low molar ADP were performed in four patients, and in three patients showed a hyperaggregable pattern.

CONCLUSIONS

The patient with thrombosis developed a transient acquired type II pattern on multimeric analysis of the von Willebrand factor, which was not seen in the other individuals studied.

Cleft palate lateral synechia syndrome. Review of the literature and case report

Cleft palate lateral synechiae syndrome is a rare syndrome consisting of cord-like interalveolar adhesions and concomitant hypoplasia of the mandible. We have presented an infant with CPLS syndrome and coincident hydrocephalus. Surgical division of the adhesions is necessary to allow normal feeding, avoid upper airway obstruction, and allow normal mandibular function and growth.

Treatment of muscle spasms with oral dantrolene sodium

A case of severe muscle spasms relieved by oral administration of dantrolene sodium is presented. The patient had undergone full-mouth extraction 2 days prior to onset of her spasms. The treatment consisted of intravenous diazepam followed by oral dantrolene sodium. The spasms lasted for approximately 10 days.

Cyclosporine-induced gingival hyperplasia: case report and literature review

A case of gingival hyperplasia was related to the use of cyclosporine for the prevention of renal allograft rejection. With the increasing use of cyclosporine to protect allograft organ transplants, general dentists and dental specialists increasingly will be called on to diagnose and treat gingival hyperplasia.