Rectus femoris muscle atrophy and recovery caused by preoperative pretibial traction in femoral shaft fractures-comparison between traction period.

BACKGROUND: Skeletal traction is performed to temporarily stabilize fracture sites before surgery in patients with femoral fracture. To date, however, there is no study evaluating the difference in the degree of the recovery, of the muscle strength, as well as muscle atrophy following skeletal traction. The purpose of this study was to compare the degree of recovery of rectus femoris muscle strength after surgery in association with muscle atrophy by analyzing the duration of preoperative tibial traction, age and sex in patients with femoral fracture. HYPOTHESIS: Rectus femoris muscle atrophy will progress depending on the duration of preoperative tibial traction, age and sex in patients with femoral fracture. PATIENTS AND METHOD: Thirty-one patients who underwent preoperative pretibial skeletal traction and intramedullary nailing were divided into two groups according to the traction period: group A (n=12) with a duration of traction of <7 days (mean: 4.08±1.78 days) and group B (n=19) ≥7 days (mean: 13.63±7.17 days). The degree of muscle atrophy and recovery were compared between the two groups, according to age and gender. The degree of muscle atrophy was measured by the difference in thickness of the rectus femoris between pre- and post-traction using ultrasound. The degree of muscle recovery was evaluated by the Q-setting and heel off time. Clinical outcome was evaluated by the non-union rate and Lysholm score. RESULTS: The degree of muscle atrophy was 0.99±0.14mm in group A and 2.22±0.11mm in group B (P<0.001). The Q-setting time was 4.83±0.94 days in group A and 6.56±1.38 days in group B (P=0.001). Heel off time was also shorter in group A at 2.58±0.90 days, taking 3.72±1.27 days in group B (P=0.012). The recovery rate in the rectus femoris was significantly higher in group A than in group B (P<0.001). There was no significant difference in non-union rate between group A and B (P=0.672) but the mean Lysholm score at the last follow-up was significantly higher in group A than in group B (P=0.006). However, no significant differences were detected in the mean thickness of the rectus femoris, Q-setting, and heel off time between the different age and gender groups (P<0.05). CONCLUSIONS: The prolonged duration of preoperative skeletal traction indicates not only that the resulting disuse atrophy would progress further but also that the muscle atrophy would be accelerated more rapidly for shorter periods of time, based on a cut-off value of 7 days. In addition, the rate of rectus femoris muscle recovery and clinical outcomes were lower in patients undergoing traction for longer periods of time. This indicates that it would be effective for increasing the rate of the recovery and minimizing the occurrence of post surgical complications if surgeons could perform surgery at the earliest possible opportunity following traction, within seven days after the onset of trauma. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Histopathological and scanning electron microscopy findings of retrieved porous polyethylene implants.

Porous polyethylene (PPE) implants are biocompatible alloplastic materials commonly used for facial augmentation. However, the effect of sub-periosteal PPE application on the surrounding tissues has not been analyzed clearly. This report documents the case of a 22-year-old woman who underwent peri-alar augmentation with PPE to improve midface retrusion. Although no infection or inflammation occurred at the surgical site, the patient requested removal of the PPE implant for aesthetic reasons alone at 1 year after the surgery. The removed implant was subjected to histological and morphological evaluation using conventional histological staining and scanning electron microscopy (SEM). Histopathological staining revealed bone ingrowth into the pores of the implant near the boundary with the host bone. Little evidence of a foreign body reaction was observed. SEM revealed densely arranged collagen fibres and osteoblastic cells in the pores. Moreover, the outer surface of the PPE implant in contact with the periosteum showed fibrous tissue ingrowth, leading to tissue adhesion. These findings confirm bone ingrowth into the PPE pore structure in humans.

Degree of conversion of dual-cured resin cement light-cured through three fibre posts within human root canals: an ex vivo study.

AIM: To evaluate the degree of conversion of one dual-cured resin cement light-cured through three fibre posts within extracted human teeth. METHODOLOGY: Fifteen mandibular premolars were root filled and then divided into three groups. Variolink II was light-cured through the posts (LP, D.T. Light-Post; PP, FRC Postec Plus; SP, Snowpost) within the root canal. The degree of conversion was obtained at 1 mm intervals in 9 mm-deep longitudinally sectioned root canals using an optical microscope connected to an FTIR spectrophotometer (n = 10). The light transmission of each post tested was also examined using UV-Vis spectroscopy. Data were analysed using ANOVA and Tukey's test (alpha = 0.05). RESULTS: The LP and PP posts revealed a light transmission of 10.2% and 7.7%, respectively, whereas the SP post exhibited a significantly lower value of 0.5%. The degree of conversion mean value ranged from 32.78% to 69.73% depending on the depth and type of post. For all the groups, there were significant decreases in the degree of conversion values for the middle region when compared with those for the cervical region (P < 0.05). Except at a depth of 1 mm, the SP group consistently exhibited significantly lower degree of conversion values than the other groups (P < 0.05). The linear regression analysis revealed a strong correlation between the light transmission of the posts and the overall degree of conversion value for each group (R(2) = 0.9888). CONCLUSIONS: The decrease in the degree of conversion for Variolink II relative to the depth was dependent on the light transmission capacity of the posts tested.

Calcium phosphate-based coatings on titanium and its alloys.

Use of titanium as biomaterial is possible because of its very favorable biocompatibility with living tissue. Titanium implants having calcium phosphate coatings on their surface show good fixation to the bone. This review covers briefly the requirements of typical biomaterials and narrowly focuses on the works on titanium. Calcium phosphate ceramics for use in implants are introduced and various methods of producing calcium phosphate coating on titanium substrates are elaborated. Advantages and disadvantages of each type of coating from the view point of process simplicity, cost-effectiveness, stability of the coatings, coating integration with the bone, cell behavior, and so forth are highlighted. Taking into account all these factors, the efficient method(s) of producing these coatings are indicated finally.

An evaluation of localized debonding between fibre post and root canal wall by finite element simulation.

AIM: To investigate the effect of localized bonding defects between fibre post and root canal wall on the stress distribution in the radicular dentine. METHODOLOGY: A tooth restored with a fibre post together with the alveolar bone were axisymmetrically modelled. A total of four models with localized debonding at the post to canal wall interface in different locations were analysed: Model A: perfect bonding layer over the entire interface; Model B: debonding at the cervical 1/3 of the interface; Model C: debonding at the mid 1/3; and Model D: debonding at the apical 1/3. A tooth restored without using a post was also included as the control (Model E). A load of 50 N was applied to the top of the full veneer cast crown at angles of 0, 15, 30, and 45 degrees with the tooth's longitudinal axis. The stress distribution across the fibre post and root dentine was compared. RESULTS: Higher stresses were generated in the radicular dentine as a function of the load angle. The differences in the stress distribution were negligible between the four models and virtually the same as that for model E (control). CONCLUSIONS: In this simulation, localized debonding at the fibre post to root canal wall interface, regardless of its location along the post, had little effect on the stress distribution in the root dentine.

Sweep optical frequency synthesizer with a distributed-Bragg-reflector laser injection locked by a single component of an optical frequency comb.

A sweep optical frequency synthesizer is demonstrated by using a frequency-stabilized optical frequency comb and injection-locked distributed-Bragg-reflector (DBR) laser diode. The injection-locked DBR laser acts as a single-frequency filter and, simultaneously, a high-gain amplifier of the optical frequency comb. The frequency instability of the heterodyne beat signal between two independently injection-locked DBR lasers is measured to be 2.3 x 10(-16) at 1 s averaging time. The output frequency of the sweep optical frequency synthesizer can be precisely tuned over 1 GHz, and a saturated absorption spectrum of the Cs D2 line at 852 nm is recorded by the injected DBR laser.

FT-Raman spectroscopy of calcium hydroxide medicament in root canals.

AIM: To investigate chemical changes in calcium hydroxide introduced into human root canals as a medicament using Fourier transform-(FT) Raman spectroscopy. METHODOLOGY: Ten necrotic maxillary anterior teeth were selected in 10 patients. The teeth were divided into five treatment groups, according to the survey time. Root canal instrumentation was performed with hand instruments until the master apical file was size 40. Calcium hydroxide paste, in a 1 : 1.25 mixture by weight of powder and distilled water, was introduced directly into the root canal with a lentulo-spiral filler and then condensed with a finger plugger. The access cavity was sealed with a temporary dressing. After 2 and 4 days, then 2, 4 and 6 weeks, the calcium hydroxide paste was sampled with a K-file and then analysed using FT-Raman spectroscopy. The excitation source was an Nd : YAG laser with an excitation wavelength of 1064 nm. All spectra were taken with a laser power of 200 mW, 275-1185 scans, and 4 cm(-1) resolution. The conversion of calcium hydroxide to calcium carbonate was calculated on the basis of the spectral data obtained from the mixtures of both compounds. RESULTS: The calcium hydroxide paste in the apical region showed weak bands at 1088 and 284 cm(-1), in addition to bands associated with calcium hydroxide. The weak bands, assigned to calcium carbonate, became stronger with time. Calcium carbonate content increased rapidly in the first 2 days and then tended to increase slowly. Approximately 11% of the calcium hydroxide at the apical portion of the canal was converted to calcium carbonate after 6 weeks. However, little alteration of the paste was noticed in the samples from the middle portion of the canal. CONCLUSIONS: Calcium hydroxide medicament in root canals became transformed into calcium carbonate in the apical region within 2 days. Although the transformation continued with time, approximately 90% of the calcium hydroxide remained unchanged after 6 weeks.

The effect of 30% hydrogen peroxide on the color of compomers.

The interaction between bleaching agents and recently introduced compomers has several issues that need to be explored, including morphology and mechanical properties. To investigate the effect of 30% hydrogen peroxide, a bleaching agent, on the color of compomers, three compomers (Compoglass F, Elan, and F2000) were polymerized, bleached up to 120 h, and then measured to determine the reflectance of the specimen during the bleaching process. Color differences were evaluated from the reflectance and color values that were represented by CIE L*a*b* values. Compomers stored in distilled water were used as a source of reference. Teeth were also used for comparison. Color differences for both the tested teeth and compomers and different periods of bleaching and soaking in distilled water showed statistically significant difference (p < 0.0001). Among the tested compomers, Compoglass F demonstrated the highest color difference. In addition, the color differences were maximal during the first 24 h. After 24 h, the color difference increased nearly linearly. Compomers stored in both a bleaching agent and distilled water did not exhibit much color difference between them. However, the color difference between teeth and compomers was considerable.

Ciliary beat frequency in cultured human nasal epithelial cells.

This study aimed to determine the characteristics of ciliogenesis and the ciliary beat frequency (CBF) of cultured human nasal epithelial cells by means of an in vitro air-liquid interface (ALI) culture system. On the 14th, 21st, and 27th days of ALI culture, CBFs of cultured cells were measured with a video computerized analysis system, and the epithelial cell-collagen matrix complex was examined by scanning and transmission electron microscopy. Using a CBF distribution map, we calculated the proportion of ciliary beating area (CBA) on the cultured cells. On the 14th day, ciliated cells could be easily distinguished from other cells on scanning electron microscopy by their elongated cilia. Between the 14th and 27th days, the number of mature cilia increased, and after 27 days of air exposure, the cilia of each cell pointed to one direction. From the beginning of air-exposure culture until the 7th day, the number of secretory cells increased; however, from the 7th day to the 27th day, it decreased, and the number of ciliated cells increased. Total CBAs increased from the 7th day to the 21st day. The proportions of actively beating cells and the mean CBFs of beating cells among cultured epithelial cells increased with culture time. On the 21st day, the mean CBF of the cultured cells was similar to that of nasal ciliated cells in biopsy specimens (10.9 +/- 0.5 Hz versus 11.4 +/- 1.3 Hz), but until the 27th day, the CBF of cultured cells increased significantly (13.9 +/- 0.8 Hz). It is suggested that there may be some difference in CBF between nasal epithelial cells submitted to biopsy and nasal epithelial cells cultured by the ALI culture system.

Regulation of mucociliary motility by nitric oxide and expression of nitric oxide synthase in the human sinus epithelial cells.

OBJECTIVES: This study was performed to investigate the changes in ciliary beat frequency (CBF) after treatment with Larginine in the human sinus mucosa and to determine the distribution of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in the healthy sinus mucosa. STUDY DESIGN/METHODS: CBF was measured in the sphenoid sinus mucosa of 12 patients who underwent trans-septal trans-sphenoidal hypophysectomy for the treatment of pituitary gland tumor. CBF was measured over 24 hours in Dulbecco's modified Eagle's medium (DMEM) after treatment with L-arginine, its inactive spatial isomer D-arginine, or an NOS inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME). DMEM without treatment with these materials was used as a control. Other pieces of the mucosa were exposed to L-NAME and its inactive spatial isomer D-NAME after preincubation with L-arginine. The specimens were immunohistochemically stained for iNOS and eNOS. RESULTS: CBF increased 24 hours after treatment with L-arginine as compared with control groups. CBF increased in proportion to the increasing concentrations of L-arginine. There was no significant change after treatment with D-arginine or L-NAME. CBF increased after treatment with L-arginine at 30 minutes and maintained for 24 hours. L-NAME inhibited the increase in CBF by L-arginine, but D-NAME showed no such effect. Immunoreactivity to both iNOS and eNOS was frequently observed in the ciliated epithelial cells and was stronger to eNOS than to iNOS. CONCLUSIONS: From the results of this study it is suggested that nitric oxide (NO) produced by iNOS and eNOS using L-arginine may increase CBF in the healthy sinus mucosa and that NO may have a regulatory function in ciliary motility in the human sinus mucosa.

Changes of nasal function after temperature-controlled radiofrequency tissue volume reduction for the turbinate.

OBJECTIVES: Temperature-controlled and temperature-monitored radiofrequency tissue volume reduction (RFTVR) for the turbinate is a new treatment modality for nasal obstruction secondary to turbinate hypertrophy. We compared the nasal functions after the treatment ofRFTVR and laser vaporizing turbinoplasty (LVT) using subjective symptom scores and objective tests. STUDY DESIGN: Prospective, randomized clinical trial. METHODS: Twenty-four patients with nasal obstruction secondary to inferior turbinate hypertrophy were prospectively evaluated from March 1999 to October 1999 at Seoul National University Hospital (Seoul, Korea). Sixteen patients were treated with RFTVR, and eight patients with LVT. The preoperative and postoperative nasal functions were investigated by visual analogue scale of symptoms, butanol threshold test, saccharine test, acoustic rhinometry, rhinomanometry, and ciliary beat frequency. RESULTS: At 8 weeks postoperatively, the severity and the frequency of nasal obstruction improved subjectively in 81.3% and 93.8% of RFTVR group and in 87.5% and 87.5% of LVT group, respectively. Significant improvement of nasal symptoms began from 2 to 3 days after the operation in the RFTVR group, whereas there was significant improvement of nasal symptoms at 8 weeks after operation in the LVT group. However, objective nasal functions including nasal volume and total nasal resistance were significantly improved at 8 weeks after surgery in both groups. Among patients reporting symptoms of hyposmia, 55.6% of RFTVR group and 63.6% of LVT group showed improved olfaction. Saccharin transit time and ciliary beat frequency were preserved after RFTVR CONCLUSION: RFTVR for the turbinate may be useful as an alternative approach for the treatment of chronic turbinate hypertrophy.

Effects of beta-toxin of Staphylococcus aureus on ciliary activity of nasal epithelial cells.

OBJECTIVES: To investigate the in vitro effects of staphylococcal beta-toxin on ciliary activity and the in vivo effects on sinusitis induction. STUDY DESIGN: The in vitro effects of staphylococcal beta-toxin on ciliary activity were investigated at different concentrations and exposure times. Experimental sinusitis was induced in rabbits with application of beta-toxin and confirmed 7 days later. METHODS: Ciliated epithelial cells were taken from the maxillary sinus mucosa of 10 rabbits. Five culture dishes from each rabbit were used for the experimental group, and one culture dish from each rabbit was used for the control group. In the experimental group, ciliary beat frequency (CBF) was measured at concentrations of 0.1, 1, 2, 5 and 10 U/mL of beta-toxin using a video-computerized analysis technique, while in the control group, culture medium containing no toxin was used. CBF was measured 1, 2, 4, 6, 8, 12, 24, and 48 hours after administration of beta-toxin. To induce experimental sinusitis, 2 U/mL of beta-toxin was percutaneously applied to the maxillary sinus of 10 rabbits without occlusion of the natural ostium, while normal saline was percutaneously applied to the right-side maxillary sinus of 4 rabbits in the control group. At 7 days, mucosal membranes were taken from the inferomedial wall of the maxillary sinus for light microscopic study. RESULTS: CBF dropped significantly after an 8-hour incubation at 2, 5, and 10 U/mL of beta-toxin. No ciliary activity was observed after a 24-hour incubation at 2 and 5 U/mL and a 12-hour incubation at 10 U/mL of beta-toxin. Mucoid, purulent discharge was observed in the maxillary sinuses of the beta-toxin-applied group. Prominent epithelial disruption and infiltration of inflammatory cells into the epithelium and lamina propria were observed in the beta-toxin-applied group. CONCLUSIONS: Staphylococcal beta-toxin may reduce ciliary activity and induce sinusitis without occlusion of the natural ostium of the maxillary sinus in rabbits This study provides another animal model of sinusitis for understanding the pathogenesis of sinusitis induced by bacterial exotoxins.

Cationic liposome-enhanced adenoviral gene transfer in a murine head and neck cancer model.

The effect of combining adenoviral vector and cationic liposomes on the efficiency of gene transfer to head and neck tumor cells was investigated. Two human and two murine cell lines were used for the screening of gene transfer efficiency using an adenoviral vector. Cationic liposome-enhanced gene transfer was checked using a murine squamous carcinoma cell line, SCCVII/SF. A considerable difference in the efficiency of gene transduction was observed among the cell lines. The combination of DOSPER and adenoviral vector containing human alkaline phosphatase showed a remarkable enhancing effect in gene transfer in vitro and in vivo, compared to the adenovirus alone or control groups. With an improvement in the efficiency of gene transfer, it may be possible not only to enhance the expression of transduced genes, but also to deliver a smaller amount of virus, as a result, reducing toxicity and the immune response against adenovirus.

Videostrobokymography: a new method for the quantitative analysis of vocal fold vibration.

OBJECTIVES: To develop a new analysis method for the quantitative assessment of vibration of the vocal folds, using conventional videostroboscopic image data. METHODS: We used prerecorded videostroboscopic images to evaluate quantitatively the vibration of the vocal folds. Successive images were converted as digital images by means of an image-grabbing board, processed for analysis, and reconstructed as kymograms by rearranging the same lines of all processed images along the time axis. RESULTS: We developed a new technique for evaluating the vibration of the vocal folds. The vibrations of multiple vocal fold regions were easily and objectively evaluated by this technique. The objective parameters, such as open quotient and asymmetry index, could be obtained easily using this technique. CONCLUSIONS: Videostrobokymography demonstrated objectively the vibrations of several vocal fold regions at the same time. This technique has the potential to be a new tool to analyze and monitor the pathological changes and treatment results of vocal fold movement in a more refined quantitative fashion, using videostroboscopic images.

Effect of ferric chloride/citric acid/phosphoric acid conditioner on adhesion of 4-META/MMA-TBB resin to the tooth.

The aim of this study was to examine the effects of ferric chloride/citric acid/phosphoric acid conditioners on the surface morphology of enamel and dentin and on the adhesion of 4-META/MMA-TBB resin to conditioned tooth surfaces. Seven conditioners, including phosphoric acid and its mixture with citric acid and ferric chloride, were prepared and used for treating bovine teeth before bonding with the resin. The effects of the conditioners on the surface morphology and adhesion were examined by scanning electron microscopy and by atomic force microscopy and by tensile bond strength tests, respectively. The maximum bond strengths to tooth surfaces were obtained by using 3% ferric chloride/5% citric acid/10% phosphoric acid conditioner. Thus, enamel and dentin can be treated simultaneously with this conditioner before bonding with the 4-META/MMA-TBB resin system.