Viability of diced, crushed cartilage grafts and the effects of Surgicel (oxidized regenerated cellulose) on cartilage grafts

The viability of cartilage grafts has been well documented; however, controversy still exists about the viability of crushed cartilage. Recently, there has been a tendency to use diced cartilage grafts wrapped with oxidized regenerated cellulose (Surgicel) sheets for improving dorsal contour in rhinoplasty. The viability of diced cartilage grafts and the effect of Surgicel on cartilage grafts are not well known. In this study, we used ear cartilage from 18 New Zealand rabbits. Cartilage grafts were transplanted to surgically created subcutaneous pockets on the back of the rabbits on both the left and right sides. There were three groups: (1) intact cartilage grafts, (2) crushed cartilage grafts, and (3) diced cartilage grafts. The grafts that were transplanted to the right side were wrapped with Surgicel. Cartilage grafts in all groups were viable. In grafts that were wrapped with Surgicel, a marked increase in the collagen content was investigated. Grafts that were wrapped with Surgicel demonstrated no evidence of proliferation, whereas the bare cartilage grafts demonstrated significant amounts of proliferation.

Electrochemical Determination of Food Preservative Nitrite with Gold Nanoparticles/p-Aminothiophenol-Modified Gold Electrode

Due to the negative impact of nitrate and nitrite on human health, their presence exceeding acceptable levels is not desired in foodstuffs. Thus, nitrite determination at low concentrations is a major challenge in electroanalytical chemistry, which can be achieved by fast, cheap, and safe electrochemical sensors. In this work, the working electrode (Au) was functionalized with p-aminothiophenol (p-ATP) and modified with gold nanoparticles (Au-NPs) to manufacture the final (Au/p-ATP-Aunano) electrode in a two-step procedure. In the first step, p-ATP was electropolymerized on the electrode surface to obtain a polyaminothiophenol (PATP) coating. In the second step, Au/p-ATP-Aunano working electrode was prepared by coating the surface with the use of HAuCl₄ solution and cyclic voltammetry. Determination of aqueous nitrite samples was performed with the proposed electrode (Au/p-ATP-Aunano) using square wave voltammetry (SWV) in pH 4 buffer medium. Characteristic peak potential of nitrite samples was 0.76 V, and linear calibration curves of current intensity versus concentration was linear in the range of 0.5-50 mg·L(-1) nitrite with a limit of detection (LOD) of 0.12 mg·L(-1). Alternatively, nitrite in sausage samples could be colorimetrically determined with high sensitivity by means of p-ATP‒modified gold nanoparticles (AuNPs) and naphthylethylene diamine as coupling agents for azo-dye formation due to enhanced charge-transfer interactions with the AuNPs surface. The slopes of the calibration lines in pure NO₂(-) solution and in sausage sample solution, to which different concentrations of NO₂(-) standards were added, were not significantly different from each other, confirming the robustness and interference tolerance of the method. The proposed voltammetric sensing method was validated against the colorimetric nanosensing method in sausage samples.

Total monoamine oxidase (MAO) inhibition by chestnut honey, pollen and propolis

Monoamine oxidase (MAO) inhibitors are generally used in the treatment of depressive disorders and some neurodegenerative illnesses, such as Parkinson's disease and Alzheimer's disease. The aim of this preliminary study was to investigate the MAO [MAO (E.C.1.4.3.4)] inhibiting effect of various apitherapeutic products, such as chestnut honey, pollen and propolis. Extracts' MAO inhibition was measured using peroxidase-linked spectrophotometric assay in enzyme isolated from rat liver microsomes, and the values are expressed as the inhibition concentration (IC50) causing 50% inhibition of MAO. The antioxidant activity of the bee products was also determined in terms of total phenolic content (TPC) and ferric reducing/antioxidant power in aquatic extracts. All samples exhibited substantial inhibition of MAO, propolis having the highest. Inhibition was related to samples' TPCs and antioxidant capacities. These results show that bee products possess a sedative effect and may be effective in protecting humans against depression and similar diseases.

Novel Spectroscopic and Electrochemical Sensors and Nanoprobes for the Characterization of Food and Biological Antioxidants

Since an unbalanced excess of reactive oxygen/nitrogen species (ROS/RNS) causes various diseases, determination of antioxidants that can counter oxidative stress is important in food and biological analyses. Optical/electrochemical nanosensors have attracted attention in antioxidant activity (AOA) assessment because of their increased sensitivity and selectivity. Optical sensors offer advantages such as low cost, flexibility, remote control, speed, miniaturization and on-site/in situ analysis. Electrochemical sensors using noble metal nanoparticles on modified electrodes better catalyze bioelectrochemical reactions. We summarize the design principles of colorimetric sensors and nanoprobes for food antioxidants (including electron-transfer based and ROS/RNS scavenging assays) and important milestones contributed by our laboratory. We present novel sensors and nanoprobes together with their mechanisms and analytical performances. Our colorimetric sensors for AOA measurement made use of cupric-neocuproine and ferric-phenanthroline complexes immobilized on a Nafion membrane. We recently designed an optical oxidant/antioxidant sensor using N,N-dimethyl-p-phenylene diamine (DMPD) as probe, from which ROS produced colored DMPD-quinone cationic radicals electrostatically retained on a Nafion membrane. The attenuation of initial color by antioxidants enabled indirect AOA estimation. The surface plasmon resonance absorption of silver nanoparticles as a result of enlargement of citrate-reduced seed particles by antioxidant addition enabled a linear response of AOA. We determined biothiols with Ellman reagent-derivatized gold nanoparticles.

Sarcoma developing in a burn scar: case report and review of the literature

The development of malignancy in burn scars is a well known entity. However, burn scar sarcomas are rarely seen. This report presents the first case of a leiomyosarcoma arising in a burn scar of scalp in the English literature.

Tissue engineering of high density porous polyethylene implant for three-dimensional reconstruction: an experimental study

Three-dimensional defects have been reconstructed with carved and remodelled frameworks wrapped within vascular carriers. If sufficient vascular penetration can be established without any change in the size and shape of an implant, it will be possible to cover it with a skin graft and aesthetically important fine details can be obtained. To achieve this, we first prefabricated high-density porous polyethylene implant in rabbits. Secondly, we applied full-thickness skin grafts over the anterior surface of the prefabricated implant. The implants were placed and anchored underneath the superficial inferior epigastric artery and vein pedicle bilaterally. A total of 10 implants were prefabricated and then grafted in five rabbits. The implants were evaluated by perfusion scintigraphy and histological examination. Results showed that the implants were invaded by fibroneo-vascular tissue, and that this tissue, which can be transferred as a pedicled or a free flap, was sufficient to sustain a skin graft.

Detection of nitric oxide radical and determination of its scavenging activity by antioxidants using spectrophotometric and spectrofluorometric methods

Although reactive nitrogen species (RNS) may attack biomacromolecules and cause tissue damage when unbalanced by natural antioxidant defenses of the organism, they can also take part in cell signaling under different physiological states and defend against certain pathogens. Since there is a scarcity of analytical methods to detect radicalic NO and its scavengers, a functionalized gold nanoparticle-based spectrophotometric method and a spectrofluorometric method have been separately developed to test antioxidant activity toward scavenging of NO produced from sodium nitroprusside (SNP). The spectrophotometric method involves conversion of NO to nitrite, followed by the formation of an azo dye with 4-aminothiophenol (4-ATP)-modified gold nanoparticles (AuNPs) and N-(1-naphthyl)-ethylene diamine dichloride (NED) and its absorbance measurement at 565 nm. Calibration equations were established by taking the absorbance difference in the presence and absence of antioxidants. In the spectrofluorometric method, the excess of NO radicals, after being scavenged by thiol type antioxidants, caused a decrease in resorcinol fluorescence. The developed spectrophotometric method was applied to orange juice and its trolox equivalent (TE) antioxidant activity was found. By further applying the developed methods to real samples such as bovine serum albumin (BSA), fetal bovine serum (FBS), saliva and certain biomolecules, it is envisaged that these novel methods improving the selectivity of previous methods can be useful in human health and disease research associated with nitric oxide. The developed methods were compared and validated against the conventional Griess assay with Student t-test and F tests.

Prefabrication of a high-density porous polyethylene implant using a vascular induction technique

Three-dimensional defects have been reconstructed with carved and remodeled frameworks wrapped within vascular carriers and have wide use in ear and nose reconstruction. The main problem with thick coverings is masking of the fine details in the frameworks. Other problems are insufficient blood supply, infection, and exposure of the implant. If sufficient vascular penetration can be established without any change in size and shape of the implant, it will be possible to cover it with a thin skin graft and improve aesthetic results. In this study we planned to prefabricate a high-density porous polyethylene implant that has been used frequently. The implants were placed and anchored underneath the superficial inferior epigastric artery and vein pedicle bilaterally in 10 adult New Zealand White rabbits. Twenty implants were prefabricated in this procedure, and they were evaluated via histological examination and perfusion scintigraphy. Results revealed that the implants were invaded by fibroneovascular tissue. Blood supply coming from the vascular pedicle was sufficient to maintain the implant as a prefabricated composite flap, which could be transferred as a pedicled flap or a free flap.

Pilomatrixoma of the earlobe

BACKGROUND

Pilomatrixoma most commonly occurs in the head and neck region, appearing primarily in the first two decades of life. The lesion is described as a tumor with differentiation toward hair cells and surgical excision is the treatment of choice.

OBJECTIVE

We report an uncommon localization of a perforating type pilomatrixoma of 5 x 4 x 4 cm in size that developed from the earlobe.

METHODS

Histopathological examination revealed pilomatrixoma. Total resection of the tumor was performed. The earlobe was reconstructed by forming a posterior-superior pedicled skin flap.

RESULTS

No recurrence was observed and a good cosmetic result was obtained.

CONCLUSION

Local recurrence does not generally occur if the tumor is completely removed. The case we present is of interest in having a history of trauma to the region and a relatively rapid growth with perforation of the overlying skin.

Colorimetric sensors and nanoprobes for characterizing antioxidant and energetic substances

The development of analytical techniques for antioxidant compounds is important, because antioxidants that can inactivate reactive species and radicals are health-beneficial compounds, also used in the preservation of food and protection of almost every kind of organic substance from oxidation. Energetic substances include explosives, pyrotechnics, propellants and fuels, and their determination at bulk/trace levels is important for the safety and well-being of modern societies exposed to various security threats. Most of the time, in field/on site detection of these important analytes necessitates the use of colorimetric sensors and probes enabling naked-eye detection, or low-cost and easy-to-use fluorometric sensors. The use of nanosensors brings important advantages to this field of analytical chemistry due to their various physico-chemical advantages of increased surface area, surface plasmon resonance absorption of noble metal nanoparticles, and superior enzyme-mimic catalytic properties. Thus, this critical review focuses on the design strategies for colorimetric sensors and nanoprobes in characterizing antioxidant and energetic substances. In this regard, the main themes and properties in optical sensor design are defined and classified. Nanomaterial-based optical sensors/probes are discussed with respect to their mechanisms of operation, namely formation and growth of noble metal nanoparticles, their aggregation and disaggregation, displacement of active constituents by complexation or electrostatic interaction, miscellaneous mechanisms, and the choice of metallic oxide nanoparticles taking part in such formulations.

Malignant triton tumor of the maxilla: a patient report

Malignant Triton tumor (or malignant schwannoma with rhabdomyoblastic differentiation) is a rare entity with a very poor prognosis. This is the second report of this type of rare and aggressive sarcoma arising in the maxilla. The clinical course, therapeutic approach, and histopathological aspects of the case are presented.

Implantation of Novel Small-Diameter Polyurethane Vascular Prostheses Interposed in Canine Femoral and Carotid Arteries

OBJECTIVES

The performance of small-diameter (3-5-mm) vascular grafts still poses a challenge in the field of vascular surgery. We present here our preliminary experience with implanting unique small-sized polycarbonate urethane vascular grafts in 7 dogs.

MATERIAL AND METHODS

Each animal was implanted with 4 interposition grafts, 2 femoral and 2 carotid. No anti-thrombotic medication was administered. Doppler sonography was performed at 3-month intervals to examine for patency and flow characteristics. Animals were sacrificed electively at 3, 6 and 12 months.

RESULTS

At 3 months, all grafts were patent. After 6 months, 3 grafts occluded and at 1 year a further 6 grafts occluded. Hence 9 of 28 grafts occluded (67.9% patency). During the study, no correlation could be established between flow velocity or resistance index and occlusion. Histopathology showed intimal hyperplasia to be the cause of occlusion.

CONCLUSIONS

Compared to literature data on small-diameter grafts in the same position, ADIAM's Biomechanical grafts performed clearly better. Compliance data suggest a correlation between elastic compliance and patency.

Dipyrone increases the blood flow of arterial dorsal skin flaps

BACKGROUND

Findings have shown that dipyrone has a beneficial effect on skin flap survival. A pharmacologic explanation for this effect points to its vascular smooth muscle-relaxing effect. This study evaluated the effect of dipyrone on blood flow and thus survival of rat random dorsal skin flaps.

METHODS

For this study, 27 male Wistar albino rats were randomly assigned to control (treated with sterile saline) and treatment (treated with dipyrone 100 mg/kg) groups. A random dorsal skin flap measuring 4 x 10 cm was raised in each animal. The edges of the flap were sutured back into their original place. Dipyrone treatment continued at 100 mg/kg per day during the 7-day observation period. Blood flow was recorded by laser Doppler preoperatively (baseline), immediately after the flap was sutured back to its original position (acute), and on postoperative day 7. The degree of necrosis was evaluated by the grid method on day 7. Mean percentage necrosis and minimum laser Doppler readings were compared between the two groups.

RESULTS

A significant increase in blood flow was observed in the dipyrone group at the acute phase but not on postoperative day 7. The percentage of the necrotic area was lower in the treatment group. However, it did not reach the significance level (p = 0.09).

CONCLUSION

Dipyrone significantly increases [corrected] skin blood flow at the acute phase of flap elevation although the necrotic area does not reach the significance level.

The effects of tissue expansion on skin lymph flow and lymphatics: an experimental study in rabbits

Histomorphological, physiological, and biomechanical changes of the skin and tissue that are being expanded have been extensively studied in the past. The purpose of this study was to investigate whether the skin lymph flow and lymphatics may be influenced during tissue expansion, and also to study different pattern of vascular supply of skin on lymph flow during tissue expansion. The skin lymph flow was quantitatively assessed by 99mTc-dextran lymphoscintigraphy, and the structure of dermal lymphatics was evaluated by histological examination in 12 rabbits. Lymphoscintigraphic results showed that lymph flow is significantly reduced both in expanded and non-expanded (sham-operated) skin. Histologically, we saw widespread lymphatic distension in both expanded and non-expanded skin. There were no quantitative differences in the number of lymphatic vessels compared with control skin. We did not see any lymphatic capillaries in the subdermal capsule of either expanded or non-expanded skin. These results show that lymphostasis has an obstructive (mechanical) aetiology, and the tissue expander itself reduces the lymph flow regardless of expansion, and interferes with the formation of new lymphatic vessels.

Magnetite nanoparticles-based hydroxyl radical scavenging activity assay of antioxidants using N, N-dimethyl-p-phenylenediamine probe

Excessive amounts of reactive oxygen species (ROS), unless counterbalanced by antioxidants, can cause cellular damage under oxidative stress conditions; therefore, antioxidative defenses against ROS must be measured. With the development of nanotechnology, nanoparticles have found numerous applications in science, health, and industries. Magnetite nanoparticles (Fe ₃ O ₄ :MNPs) have attracted attention because of their peroxidase-like activity. In this study, hydroxyl radicals (•OH) generated by MNPs-catalyzed degradation of H ₂ O ₂ converted the N,N-dimethyl-p-phenylenediamine (DMPD) probe into its colored DMPD•+ radical cation, which gave an absorbance maximum at λ = 553 nm. In the presence of antioxidants, •OH was partly scavenged by antioxidants and produced less DMPD• ⁺ , causing a decrease in the 553 nm-absorbance. Antioxidant concentrations were calculated with the aid of absorbance differences between the reference and sample solutions. The linear working ranges and trolox equivalent antioxidant capacity coefficients of different classes of antioxidants were determined by applying the developed method. In addition, binary and ternary mixtures of antioxidants were tested to observe the additivity of absorbances of mixture constituents. The method was applied to real samples such as orange juice and green tea. Student t-test, F tests, and the Spearman’s rank correlation coefficient were used for statistical comparisons.

Electrochemical Determination of N‑Guanylurea Dinitramide (FOX-12) Using a Poly(Methyl Orange)-Modified Carbon Nanotube Electrode

This study introduces a novel electrochemical method and a sensor electrode designed for the first time to enable the selective and sensitive quantification of N-guanylurea dinitramide (FOX-12) via square-wave voltammetry (SWV). A glassy carbon (GC) electrode was surface-modified to create the new working electrode using poly-(methyl orange: MO), which was altered by electropolymerizing the acid/base indicator MO using cyclic voltammetry and dripping well-dispersed multiwalled carbon nanotubes solution onto the electrode surface. The current intensity was correlated to the concentration of FOX-12, and the calibration line was built between 10 and 100 mg L-1 of FOX-12. The limit of detection (LOD) and the limit of quantitation (LOQ) for FOX-12 were 1.5 mg L-1 and 5.0 mg L-1, respectively, and its distinctive reduction peak potential was determined to be around -1.25 V. Additionally, the modified GC/MWCNTs/pMO electrode was effectively used to measure FOX-12 in the presence of synthetic and real mixtures of energetic substances. Furthermore, FOX-12 (50 mg L-1) was quantitatively recovered at 40-fold concentrations of common soil ions and 10-fold concentrations of camouflage materials. The proposed method was applied to clay soil samples polluted with FOX-12 and validated against an HPLC method using the statistical t- and F-tests.