Soft tissue regeneration in animal models using grafts from adipose mesenchymal stem cells and peripheral blood fibrin gel

OBJECTIVE

Our study aimed to evaluate the effect of soft tissue regeneration in nude mice using grafts made from the combination of adipocytes from fat tissue mesenchymal stem cells and fibrin gel from peripheral blood.

MATERIALS AND METHODS

Mesenchymal stem cells were isolated from adipose tissue and identified according to ISCT criteria. The scaffold used was fibrin obtained from peripheral blood. The grafts in this study were generated by transferring mesenchymal stem cells onto a fibrin scaffold. Two types of grafts, the research sample (fibrin scaffold containing adipocytes differentiated from mesenchymal stem cells) and the control sample (fibrin scaffold only), were grafted under the dorsal skin of the same mouse. After each research period, samples were collected and evaluated by histological methods to observe the existence and growth of cells inside the grafts.

RESULTS

The results showed that the study group's graft integrated better within the tissue when compared with the control group. In addition, the grafts in the study group showed the presence of cells with characteristic morphology of adipocytes one week after transplantation. In contrast, control samples showed dimorphous shapes and features mainly composed of non-homogenous fragments.

CONCLUSIONS

These initial conclusions might be considered a first step in generating safe bio-compatible engineered grafts specifically usable in post-traumatic tissue regeneration procedures.

The peculiar size and temperature dependence of water diffusion in carbon nanotubes studied with 2D NMR diffusion-relaxation D -T 2eff spectroscopy

It is well known that water inside hydrophobic nano-channels diffuses faster than bulk water. Recent theoretical studies have shown that this enhancement depends on the size of the hydrophobic nanochannels. However, experimental evidence of this dependence is lacking. Here, by combining two-dimensional nuclear magnetic resonance diffusion-relaxation ( D - T 2 e f f ) spectroscopy in the stray field of a superconducting magnet and molecular dynamics simulations, we analyze the size dependence of water dynamics inside Carbon Nanotubes (CNTs) of different diameters ( 1.1 - 6.0  nm), in the temperature range of 265 - 305  K. Depending on the CNT diameter, the nanotube water is shown to resolve in two or more tubular components acquiring different self-diffusion coefficients. Most notably, a favorable CNT diameter range ( 3.0 - 4.5  nm) is experimentally verified for the first time, in which water molecule dynamics at the center of the CNTs exhibits distinctly non-Arrhenius behavior, characterized by ultrafast diffusion and extraordinary fragility, a result of significant importance in the efforts to understand water behavior in hydrophobic nanochannels.

Early postextraction implants may achieve osseointegration in the absence of primary stability. A pilot study

This pilot study aimed at investigating if implants without primary stability may osseointegrate and support functional prosthesis. Patients received one Trabecular Metal implant each in posterior sockets two months after tooth extraction, combined with xenograft and a resorbable membrane. Implants were divided in three groups, based on the primary stability assessed by resonance frequency analysis. Implant stability quotient (ISQ) was measured at placement, and re-assessed five months later (at uncovering), and after 6 months of function. Marginal bone loss was radiographically evaluated. After checking normality of the distributions, Student's t-test was used for statistical comparisons. Twenty-five consecutive patients were included. At placement, mean ISQ significantly differed among groups, being undetectable (n=8 implants), 65.00±4.25 (standard deviation, n=6) and 77.95±3.13 (n=11) in the very low, medium and good primary stability groups, respectively. After five months of healing, mean ISQ had increased to >70 in all groups. All implants successfully osseointegrated and were restored as planned. Six months after loading, no significant difference in mean ISQ (range 79.19-81.92), and in mean marginal bone level change (range 0.21 to 0.28 mm) was observed among the three groups. Rehabilitation of wide postextraction defects may achieve successful outcomes even in the absence of primary stability.

Tailor-made graphite oxide–DAB poly(propylene imine) dendrimer intercalated hybrids and their potential for efficient CO2 adsorption

We report the rational design and synthesis of DAB poly(propylene imine) dendrimer (DAB) intercalated graphite oxide (GO) hybrids with tailorable interlayer distances.

Removal of Reactive Red 195 from aqueous solutions by adsorption on the surface of TiO2 nanoparticles

Nanoparticles of TiO2 were synthesized and characterized by XRD, BET, TG/DTA and TEM measurements. The commercial azo dye Reactive Red 195 (RR195) was selected as a model dye in order to examine the adsorption capacity of TiO2 at room temperature, under dark conditions. It was demonstrated that RR195 could be efficiently adsorbed in aqueous suspension of TiO2. A study on the effects of various parameters like initial pH, concentration of dye and concentration of adsorbent has been carried out in order to find optimum adsorption conditions. The optimum pH of sorption was 3. Substantial reduction of COD, besides removal of colour, was also achieved. The experimental data were analyzed by the Langmuir and Freundlich adsorption models. Equilibrium data fitted very well with the Langmuir model signifying the energetic homogeneity of TiO2 surface adsorption sites. At the temperature of 30 degrees C, the maximum monolayer adsorption capacity obtained from the Langmuir model is approximately 87 mg/g (pH 3.0). Kinetic studies were carried out and showed a rapid sorption of dye in the first 30 min while equilibrium was reached at 1h. Three kinetic adsorption models were used to describe the kinetics data, the pseudo-first-order model, the pseudo-second-order model and the intraparticle diffusion model. The sorption kinetics of dye was best described by the pseudo-second-order kinetic model.

Peri-implant bone reactions to immediately loaded implants. An experimental study in monkeys

BACKGROUND

There are reports which demonstrate that immediately loaded splinted implants can be osseointegrated when they are placed in the anterior part of the lower jaw. The concept of immediate loading has not been well investigated in the posterior mandible. The aim of this study was to evaluate the bone reactions around immediately loaded implants placed in the posterior region of the lower jaw in the monkey model.

METHODS

Six adult Macaca fascicularis monkeys were used in this study. A total of 36 implants were placed after extraction of the second premolars, first and second molars, and complete healing of the sockets. Three control (C) group implants were placed in one quadrant of the lower jaw of each monkey. After a delay of 3 months to allow osseointegration to take place, the implants were loaded for 1 month using temporary resin bridges and later for 2 months using metal splinted crowns. In the contralateral region of the lower jaw, 3 test (T) group implants were placed and loaded immediately with the same sequence as carried out for the C implants. Specimens were examined and evaluated histologically after sacrifice.

RESULTS

All of the implants were osseointegrated. Compact, cortical bone in contact with the implant surface without any gaps or connective tissue formation was observed.

CONCLUSIONS

It was concluded that immediately loaded, splinted implants can be osseointegrated with a similar hard and soft tissue peri-implant response as delayed-loaded implants in the posterior mandible.

A preliminary study of healing of superpulsed carbon dioxide laser incisions in the hard palate of monkeys

BACKGROUND AND OBJECTIVE

Prior studies of laser wound healing using different animal models have shown a delayed tissue response after carbon dioxide (CO2) laser application. This article reports on the preliminary findings of healing of superpulsed CO2 laser and scalpel incisions in the hard palate of monkeys.

STUDY DESIGN/MATERIALS AND METHODS

Twelve parallel incisions using a superpulsed, continuous wave CO2 laser and a scalpel were performed in the hard palate of each of two adult monkeys at 3, 7, and 14 days time schedules. Power levels of 2.0, 4.0, and 6.0 Watts were used for the laser incisions. Wounds were harvested, fixed in 10% formalsaline for at least 48 hours and processed routinely. Each specimen was embedded in paraffin wax at 90 degrees to the surface epithelium and 5 microm thick sections prepared for staining with haematoxylin and eosin, Periodic acid Schiff and Masson-trichrome at a step-serial interval of 100 microm. Sections were evaluated independently.

RESULTS

According to the clinical findings we showed a wound closure in all of the wounds (laser and scalpel incisions) at 3, 7, and 14 days of healing. Histologically, we showed that laser incisions at three and seven days demonstrated an increased, power setting-dependent tissue necrosis and marked inflammatory response with minimal organization compared to scalpel incisions. At 14 days both types of incisions exhibited complete wound healing of the epithelium and connective tissue.

DISCUSSION AND CONCLUSIONS

According to these preliminary results, superpulsed CO2 laser tends to produce more pronounced changes (due to tissue thermal damage) with corresponding greater inflammatory reaction and delay in tissue organization only initially.

Diode laser (980 nm) in oral and maxillofacial surgical procedures: clinical observations based on clinical applications

OBJECTIVE

The aim of this study was to examine the wound healing of soft tissue after the application of a diode laser (980 nm) in oral surgical procedures.

SUMMARY BACKGROUND DATA

Like the CO2 laser, the diode laser can be used for soft tissue surgery without extensive experience in the field of oral surgical.

METHODS

A diode laser was used to treat a variety of oral soft tissue lesions in 22 patients. The oral surgical procedures included removal of soft tissue tumors, frenectomies, excision of gingival hyperplasias, vestibuloplasties, hemangioma removal, and periimplant soft tissue surgery. The laser was used in both pulsed and continuous modes, with and without contact to the tissue. Intraoperative and postoperative clinical observations are reported.

RESULTS

Our preliminary clinical findings include sufficient hemostasis and precise incision margin with all of the surgical procedures. The coagulation properties, associated with the use of a diode laser, were particularly beneficial during removal of vascular lesions. The postoperative advantages, i.e., lack of swelling, bleeding, pain or, scar tissue formation, and the good wound healing were observed in all of the clinical applications and were dependent only on the laser physical parameters used.

CONCLUSIONS

The clinical application of the diode (980 nm) laser in oral and maxillofacial surgical procedures seems to be of beneficial effect for daily practice.

Immunohistochemical distribution of the collagen types IV, V, VI and glycoprotein laminin in the healthy rat, marmoset (Callithrix jacchus) and human gingivae

The purpose of this study was to demonstrate the localization of collagen types IV, V and VI as well as the glycoprotein laminin in biopsies of healthy rat, marmoset (Callithrix jacchus) and human gingivae. The slices, after the use of indirect immunofluorescence (incubation with antibodies against these extracellular matrix components), showed the same distribution with the anti-type IV and laminin antibodies on the basement membranes of the epithelium, blood vessels and nerves. Collagen type V, as a filamentous, and collagen type VI, as microfibrillar components, were localized in a similar pattern in the different species. In contrast to the other species, collagen type VI could not be found near the basement membranes of vessels and nerves of the marmoset gingiva. This result shows differences between human and monkey tissues, but not between rat and human gingivae, and conforms the heterogeneity of collagen type VI in the various cell and tissue types.