Biomedical subjects

F Korkusuz

Publications and source records attributed to F Korkusuz.

At least 19 recordsLinked to original sources

PubMed2006

Archery performance level and repeatability of event-related EMG.

The purpose of the current study was to compare the repeatability of electromyographic linear envelopes (LE) of archery groups. Surface electromyography (EMG) signals of musculus flexor digitorum superficialis (MFDS) and extensor digitorum (MED) of 23 participants (seven skilled, six beginner archers and ten non-archers) were recorded during archery shooting. Two-second periods (clicker falls at first second) of 12 shots' EMG data were recorded, full-wave rectified and filtered (60 ms moving-average filter) for each participant's drawing arm. Repeatability was investigated by using a statistical criterion, variance ratio (VR). Archers' performances were evaluated in terms of FITA scores. The results showed that FITA scores were significantly correlated to the VRs of MFDS and MED. EMG LEs were more repeatable among archers than non-archers. Therefore, we inferred that VRs of MFDS and MED might be important variables for (a) assessing shooting techniques, (b) evaluation of archers' progress, and (c) selection of talented archers.

Analysis of Variance↗

PubMed2006

Influence of duration of total breast-feeding on bone mineral density in a Turkish population: does the priority of risk factors differ from society to society?

INTRODUCTION: Despite numerous studies on risk factors for osteoporosis the effect of breast-feeding on bone mineral density (BMD) is unclear. In this study our aim was to determine the influence of total duration of breast-feeding on BMD, and subsequent risk of osteoporosis. METHODS: A total of 1,486 postmenopausal women over the age of 40 were included in the study. Women with diseases or who were under drug treatments known to affect bone metabolism were excluded. The BMD of the lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry technique, using either the Norland XA-26 or Lunar DPX-IQ densitometers and were transferred to standard values. Patients were placed in groups of five with respect to the duration of their breast-feeding as never, 1-12 months, 12-24 months, 24-60 months, >60 months. RESULTS: One-way ANOVA test showed a significant difference between the lumbar spine and femoral neck BMD of these groups of women (p<0.001, p<0.001). Post hoc Bonferroni correction revealed that both the lumbar spine and femoral neck BMD results of women with longer duration of total breast-feeding were significantly lower than those of women with less duration of total breast-feeding. In subsequent analysis other potential risk factors were also considered in a multiple linear stepwise regression model. Years since menopause (p<0.001), weight (p<0.001), total duration of breast-feeding (p<0.001), and body mass index (p=0.001) were found to be the most important predictors for lumbar spine BMD; and age (p<0.001), weight (p<0.001), years since menopause (p<0.001), and total duration of breast-feeding (p<0.001) for femoral neck BMD. CONCLUSIONS: This study showed significant associations between total duration of breast-feeding and BMD. In conclusion, total duration of breast-feeding might be an important risk factor besides age, weight, and years since menopause in postmenopausal osteoporosis.

Aged↗

PubMed2005

Quantification the relationship between FITA scores and EMG skill indexes in archery.

Forearm electromyographic (EMG) data are assumed to be an effective method in estimating performance level in archery. The aim of the current study was to establish archery skill indexes based on EMG data. Elite (n=7, FITA score=1303.4+/-26.2), beginner (n=6, FITA score=1152+/-9.0) and non-archers (n=10, assumed FITA score=250+/-0), were involved in the study. EMG activity of Muscle flexor digitorum superficialis and Muscle extensor digitorum were quantified. Two-second periods--1 s before and 1 s after the fall of the clicker--were used to obtain averaged and rectified EMG data. The averaged and rectified EMG data were filtered by averaging finite impulse response filter with 40 ms time window and then normalized with respect to maximum voluntary contraction. To estimate FITA scores from EMG data, the following skill indexes that based on mean area under some parts of processed EMG waveforms was offered for archery. These were the pre-clicker archery skill index (PreCASI), post-clicker archery skill index (PostCASI), archery skill index (ASI) and post-clicker archery skill index 2 (PostCASI2). The correlations between rank of FITA scores and natural logarithms of archery skill indexes were significant for log(PreCASI): r=-0.66, p<0.0008; for log(PostCASI): r=-0.70, p<0.0003; for log(ASI): r=-0.74, p<0.0001; log(PostCASI2): r=-0.63, p<0.002. It is concluded that EMG skill indexes may be useful for: (a) assessing shooting techniques, (b) evaluation of archers' progress and (c) selection of talented archers.

Area Under Curve↗

PubMed2003

Bone generation on PHBV matrices: an in vitro study.

Bone formation was investigated in vitro by culturing rat marrow stromal osteoblasts in biodegradable, macroporous poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) matrices over a period of 60 days. Foams were prepared after solvent evaporation and solute leaching. PHBV solutions with different concentrations were prepared in chloroform: dichloromethane (1:2, v/v). In order to create a matrix with high porosity and uniform pore sizes, sieved sucrose crystals (300-500 microm) were used. PHBV foams were treated with rf-oxygen plasma (100 W 10 min) to modify their surface chemistry and hydrophilicity with the aim of increasing the reattachment of osteoblasts. Osteoblasts were isolated from rat bone marrow and seeded onto PHBV foams. The cell density on and in the foams was determined with MTS assay. MTS results showed that osteoblasts proliferated on PHBV. Twenty-one days after seeding of incubation, growth of osteoblasts on matrices and initiation of mineralization were observed by confocal laser scanning microscopy. Increasing ALP and osteocalcin secretion during 60 days confirmed the osteoblastic phenotype of the derived stromal cells. SEM, histological evaluations and confocal laser scanning microscopy showed that osteoblasts could grow inside the matrices and lead to mineralization. Cells exhibited spindle-like morphology and had a diameter of 10-30 microm. Based on these, it could confidently be stated that PHBV seems to be a promising polymeric matrix material for bone tissue engineering.

Absorbable Implants↗

PubMed2003

Activation patterns in forearm muscles during archery shooting.

A contraction and relaxation strategy with regard to forearm muscles during the release of the bowstring has often been observed during archery, but has not well been described. The purpose of this study was to analyze this strategy in archers with different levels of expertise; elite, beginner and non-archers. Electromyography (EMG) activity of the M. flexor digitorum superficialis and the M. extensor digitorum were recorded at a sampling frequency of 500 Hz, together with a pulse synchronized with the clicker snap, for twelve shots by each subject. Raw EMG records, 1-s before and after the clicker pulse, were rectified, integrated and normalized. The data was then averaged for successive shots of each subject and later for each group. All subjects including non-archers developed an active contraction of the M. extensor digitorum and a gradual relaxation of the M. flexor digitorum superficialis with the fall of the clicker. In elite archers release started about 100 ms after the fall of the clicker, whereas in beginners and non-archers release started after about 200 and 300 ms, respectively. Non-archers displayed a preparation phase involving extensive extensor activity before the release of the bowstring, which was not observed in elite and beginner archers. In conclusion, archers released the bowstring by active contraction of the forearm extensors, whereas a clear relaxation of the forearm flexors affecting the release movement was not observed.

Adolescent↗

PubMed2001

In vivo application of biodegradable controlled antibiotic release systems for the treatment of implant-related osteomyelitis.

In this study the construction and in vivo testing of antibiotic-loaded polyhydroxyalkanoate rods were planned for use in the treatment of implant-related osteomyelitis. The rods were constructed of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate), carrying 50% (w/w) Sulperazone or Duocid. They were implanted in rabbit tibia in which implant-related osteomyelitis (IRO) had been induced with Staphylococcus aureus. The effectiveness of the antibiotics in the treatment of IRO was determined. The establishment of IRO with bacterial inoculation was complete after 3 weeks with 100% infection rate in all groups. There was no contamination or super-infection. Both antibiotics were found to be highly effective against the bacteria. Following the application of Sulperazone-P(3-HB-co-4-HB) rods, no infective agents could be isolated from the infection site within the 6-week test period, indicating complete treatment of the infection. Macroscopical evaluation at follow-up revealed no drainage, minimal swelling and increase in local warmth, most probably due to the surgery rather than to a reaction towards the implant. The overall scores for radiological findings by the end of 6 weeks were 0.8/5 for the antibiotic-loaded rod implanted in the right limb, and 1.1/5 for the antibiotic-free rod implanted in the left limb. There was no statistical difference between the antibiotic-loaded and antibiotic-free polymeric rods. In vivo drug release was almost complete within the first week. One interesting observation, however, was that the therapy was still very effective even when the release rate was very high. In the SEM of in vitro tested rods, the polymeric component was unchanged in 2 weeks while the drug leached out, leaving voids behind. In vivo, however, the morphology of the implant was significantly modified within 6 weeks post-implantation. Since a substantial degree of the in vivo drug release was complete within 1 week, we believe that dissolution of the drug must be the predominant mechanism through which the drug release is controlled.

Absorbable Implants↗

PubMed2001

Histological and magnetic resonance imaging alterations after irradiation of meniscus using Holmium:YAG laser.

OBJECTIVE: The authors performed an experimental and a prospective clinical study to evaluate the histological and magnetic resonance imaging (MRI) alterations after irradiation of meniscus using holmium:YAG (Ho:YAG) laser VersaPulse Select 60 watts and InfraTome Delivery Systems 30 degrees Handpiece (spot size at fiber tip 0.4 mm; Coherent Medical, Palo Alto, CA). BACKGROUND DATA: Recently, some authors reported a few cases with articular cartilage damage or paraarticular osteonecrosis following arthroscopic knee surgery in which the laser was used to assist in the treatment of meniscal pathology. METHODS: Meniscus specimens in saline immersion were exposed to Ho:YAG laser irradiation. The laser wavelength was 2.1 microm and pulse duration was 250 microsec. Power settings were 1-1.5 joules per pulse and 10-15 Hz. Total laser energy used in these procedures was 2, 3.5, and 6 K joules. Eight patients with meniscal problems underwent arthroscopic partial meniscectomy using Ho:YAG laser. Total laser energy used for these surgeries was 1.5-2.5 K joules. MRI was performed preoperatively and at 6 months postoperatively. RESULTS: At higher energy levels (more than 3 K joules), separation of the gap between the collagen fibers, and a three-dimensional dispersion in the striation were observed on electron microscopic evaluation of meniscus specimens. No patient had abnormal signals in MRI (a sign of articular cartilage damage or osteonecrosis) following arthroscopic laser surgery. CONCLUSION: When higher energy level is required, conventional instruments should be preferred in the treatment of meniscal lesions. Laser should be reserved for the posteriorly located and smaller meniscal lesions.

Holmium↗

PubMed2001

Surgical repair of cartilage defects of the patella.

The structure and biomechanical forces on the patellar joint challenges researchers to define an ideal method for resurfacing the patellar cartilage. The articular surface of the patella presents variability between individuals, and has various minor articulations that bear partial or total compressive, shear, and combined forces during movement. Surgical techniques for the repair of patellar cartilage defects have evolved from cumulative advances in basic science and technology. Such surgeries include the techniques that promote either fibrocartilage formation or hyalinelike cartilage formation. Techniques promoting the formation of fibrocartilage yield short-term solutions because fibrocartilage lacks the durability and the mechanical properties of articular hyaline cartilage. Currently, there is no ideal method for the repair of patellar cartilage defects; all methods are considered experimental. Additional controlled and randomized clinical studies with large series of patients and long-term followup are required.

Cartilage Diseases↗

PubMed2001

In vivo response to biodegradable controlled antibiotic release systems.

In this study, the major goal was to evaluate in vitro and in vivo findings by macroscopy, radiology, and histology to determine the effectiveness of therapy of experimental implant-related osteomyelitis with antibiotic carrier rods constructed of microbial polyesters. The polymers used were poly(3-hydroxybutyrate-co-4-hydroxyvalerate) [P(3-HB-co-4-HB)] and poly(3-hydroxybutyrate-co-3-hydroxy- valerate) [P(3-HB-co-3-HV)]. Both the Sulperazone and the Duocid-P(3-HB-co-4-HB) rods with a drug to polymer ratio of 1:1 (w/w) were effective in treating the bone infection that was experimentally initiated by inoculation of a hemolytic strain of Staphylococcus aureus (coagulase positive; phage type 52/52b) together with metal implants into the medullary area of rabbit tibia. Macroscopical data revealed that the effectiveness of therapy was apparent at week 6 for all categories tested. Radiological findings with Duocid- and Sulperazone-loaded P(3-HB-co-4-HB) rods improved significantly when judged by changes in periosteal elevation, widening of bone shaft, new bone formation, and soft-tissue deformation after 6 weeks of implantation. Histologically the signs of infection were found to subside by weeks 3 and 6. Inflammatory cells were replaced with bone-forming cells upon treatment with Sulperazone-P(3-HB-co-4-HB) and Duocid-P(3-HB-co-4-HB). Osteoblastic activity was prominent. Intramedullary inflammation, although still present, started to be replaced by fibrous or bony tissue. Histological findings presented the subsidence of infection. In summary, the antibiotic-loaded biopolymeric rods appeared to have potential as a new controlled-release system for the treatment of implant related osteomyelitis and chronic osteomyelitis.

Animals↗

PubMed2001

Effects of step aerobics and aerobic dancing on serum lipids and lipoproteins.

BACKGROUND: To examine the effect of 8 weeks of step aerobics and aerobic dancing on blood lipids and lipoproteins. METHODS EXPERIMENTAL DESIGN: Comparative training. SETTING: Two months of physical fitness program. PARTICIPANTS: Forty-five sedentary female college student volunteers randomly assigned to one of the three groups as step aerobics (n=15), aerobic dancing (n=15) and the control group (n=15). The step aerobics and aerobic dancing groups participated in sessions of 45 min per day, 3 days per week for 8 weeks with 60-70 percent of their heart rate reserve. MEASURES: Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol levels (HDL-C), the ratio of total cholesterol to high-density lipoprotein cholesterol (TC:HDL-C). RESULTS: At the end of the 8 week period, a significant difference has been found between the step aerobics group and the control group and between the aerobic dancing group and the control group in TC levels (F[2,44]=8.38; p<0.01). A significant difference in HDL-C levels (F[2,44]=3.65; p<0.05) and TC:HDL-C ratio (F[2,44]=11.56; p<0.01) has been found only between the step aerobics group and the control group. CONCLUSIONS: These results indicate that step aerobics training is an effective training mode for modifying lipid and lipoprotein profiles of female college-aged students.

Adolescent↗

PubMed2000

Assessment of mineral density and atomic content of fracture callus by quantitative computerized tomography.

The mineral density and atomic numbers of elements in the periosteal callus and the cortex area of a healing fracture were measured by quantitative computerized tomography (QCT) to obtain accurate information on the mineralization process in rabbit tibia. The mineral density of the periosteal callus was highest on day 15 and decreased gradually throughout the experiment. This was initially detected by QCT, but not with conventional radiography. An apparent decrease in cortical bone density on days 28 and 42 after fracture was observed. Atomic numbers of elements in the cortex remained stable, indicating a possible homeostatic mechanism of mineral preservation at the fracture callus and involved cortical area. QCT may predict density alterations in the fracture callus more accurately than conventional X-ray. Further studies are essential to predict a relationship between mineral density, atomic numbers, and mechanical stability.

Animals↗

PubMed1999

Sulbactam-cefoperazone polyhydroxybutyrate-co-hydroxyvalerate (PHBV) local antibiotic delivery system: in vivo effectiveness and biocompatibility in the treatment of implant-related experimental osteomyelitis.

In this study, a novel antibiotic carrier system for use in the treatment of implant-related and chronic osteomyelitis was developed. Sulbactam-cefoperazone was introduced to rods of polyhydroxybutyrate-co-hydroxyvalerate (22 mol % HV, w/w), a member of a family of microbial-origin polymer that is biodegradable, biocompatible, and osteoconductive due to its piezoelectric property. The antibiotic-loaded carrier was implanted into the infection site that was induced by Staphylococcus aureus inoculation into the rabbit tibia. The effectiveness of this was assessed macroscopically, radiographically, bacteriologically, and histopathologically. Findings of infection subsided on day 15 and almost complete remission was observed on day 30. The control side that contained antibiotic-free rods, however, worsened. These findings prompted us to conclude that the novel biodegradable antibiotic carrier developed in the present study seems to be a promising candidate for use in the treatment of severe bone infection.

Animals↗

PubMed1999

Development of a calcium phosphate-gelatin composite as a bone substitute and its use in drug release.

This study was carried out to develop a calcium phosphate-gelatin composite implant that would mimic the structure and function of bone for use in filling voids or gaps and to release bioactive compounds like drugs, growth hormones into the implant site to assist healing. XDS analysis of the synthesized calcium phosphate revealed a calcium to phosphorus molar ratio of ca. 2.30, implying a less erodible material than hydroxyapatite (1.67). Release of the antibiotic gentamicin from the implant was with a burst, whether in situ or in vivo, followed by an almost constant release for about three months. It was found that the release rate could be decreased by increasing the density of the gelatin membrane. Upon implantation into rabbit tibia the release duration was substantially shortened (to about 4 weeks) with respect to the in situ tests basically due to the degradation of gelatin. In vivo studies with rabbits confirmed this degradation. The composite was perfectly biocompatible as shown by the histological studies. It, thus, has a great potential as a bone substitute material.

Animals↗

PubMed1999

A novel osteochondral implant.

A novel implant for the use as an osteochondral graft was designed. This implant was prepared by stepwise formation of calcium phosphate crystals within the matrix of a lyophilised collagen sponge. Chondrocytes were then grown on this material to create the osteochondral implant. The implant was characterized with light microscopy, scanning electron microscopy (SEM), electron diffraction crystallography (EDX), and IR. It was observed with IR that the implant had a peak, that was not found so distinctly in its components, at 1400 cm(-1), implying a strong interaction of the two main ingredients of the implant, calcium phosphate and collagen. This strong interaction was also shown in the graft degradation test while the untreated collagen sponge degraded rapidly (in one day) the mineral loaded implant was able to maintain its integrity for two weeks. In the chondrocyte culture medium degradation of the implant was shown by a decrease of the calcium content and calcium to phosphorous ratio. Also, EDX revealed the presence of sulfur one and two weeks after incubation, an element not found among the components of the implant, possibly due to the development of an extracellular matrix. SEM showed that the form of the crystals of calcium phosphate differed depending on whether they were prepared on the template, collagen, or in the absence of a template. The chondrocytes appeared to be growing in number on the implant and their shapes were morphologically normal. The chondrocyte loaded collagen-calcium phosphate composite could thus be considered a potential tissue engineered osteochondral implant.

Biocompatible Materials↗

PubMed1999

Non-specific inflammation and bone marrow depletion due to intramedullary porous hydroxyapatite application.

Calcium hydroxyapatite (HA) ceramics are widely used in orthopaedic surgery and are known to be biocompatible, biodegradable, and osteoinductive. Recent studies of HA have identified early stage inflammatory reactions and third-body wear following hip replacement surgery. The aim of this study was to investigate the early stage inflammatory response toward HA by means of conventional radiography, histopathology, and scanning electron microscopy (SEM). HA was implanted into the medullary area of the tibiae of rabbits and followed from one week to six months. Radiography revealed local osteoporosis on Week 6 and Month 6 in some, but not, all rabbits. SEM presented favorable bonding between the implant and the cortical bone. Eosinophilic deposition, non-specific local inflammation, and bone marrow depletion were the histopathological findings. Multinuclear cells were identified in the inflammation area. Although bone ingrowth into the pores of the HA was demonstrated, there is no doubt that HA may cause an early inflammatory reaction in the bone marrow. This inflammatory reaction is followed by bone marrow depletion and may be the early sign and the cause of HA-coated implant failure.

Animals↗

PubMed1999

The effect of extracorporeal shock wave treatment (ESWT) on bone defects. An experimental study.

The aim of this study was to investigate the effects of extracorporeal shock wave therapy (ESWT) on the formation of callus in bone defects created in rabbit radii. this study searches for an answer to whether ESWT may have a therapeutic effect on bone defects. A bone defect with a radius of 1 cm was created in both forelimbs of 20 rabbits. At the 7th, 14th, and 21st days ESWT treatment was applied to the forming callus in the right radius under fluoroscopic control. At the 6th and 12th weeks, the animals were sacrificed and callus analysis was performed by computerized scan, dual energy x-ray absorptiometer. Histological analyses were also performed. The results revealed that the average callus area in the right (ESWT applied) radial defect was greater in both groups and statistically significant at the 12th week (p < 0.05). There was no difference in bone density between defects. Histologically the callus area was greater on the right side (ESWT applied side) in both groups. However in the first group trabeculae were occupying less space on the right side. Granulation tissue areas and chondroid areas were greater on the right side. We conclude that ESWT has a disorganizing and dispersing rather than a direct osteoinductive effect on forming callus. This effect may play a therapeutic role in bone defects and in situations like callus lengthening where a greater amount of callus is necessary.

Absorptiometry, Photon↗

PubMed1998

Effect of 25-OH-vitamin D on fracture healing in elderly rats.

To investigate the effect of 25-OH-vitamin D supplements (calcidiol) on fracture healing in the elderly, an experimental model with 15 18-month-old female Wistar rats was designed. An experimental fracture in the middle third of both femora of each rat was made. Then the rats were randomly assigned to two groups: one group was subcutaneously treated with 25-OH-vitamin D during all healing processes, and the other group (the control group) was not. After 5 weeks of healing, the animals were killed and both femora were extracted. Blood samples were collected before fracture and at death to determine the levels of 25-OH-vitamin D. All bones that were extracted were subjected to a torsion test to assess healing; a significantly greater maximum shear force before failure was supported in the treated group (p < 0.01). Moreover, a positive correlation (p < 0.01; r=0.55) was found between blood levels of 25-OH-vitamin D at death and the mechanical strength of the callus. Thus, the administration of 25-OH-vitamin D after the experimental fracture significantly improved the mechanical strength of the fractured bone. If similar results are found in the human, then treatment with 25-OH-vitamin D after the occurrence of a fracture would be a good way to improve fracture healing in the elderly.

Aging↗

PubMed1998

Relation between mechanical stiffness and vibration transmission of fracture callus: an experimental study on rabbit tibia.

It has been suggested that the vibration transmission across a fracture is affected by the stages of healing of the fracture callus. This study aims to correlate the change in vibration transmission with mechanical stiffness of the callus measured by three-point bending. The right tibiae of male, three-month old local albino rabbits were osteotomized and stabilized by intramedullary fixation following open reduction. The intramedullary rods were removed on the 15th, 28th, 42nd and 90th days postoperatively and the tibiae were excised for vibration, three-point bending and bone mineral density analysis by quantitative computerized tomography (QCT). Optimum time for clinical weight bearing was determined by checking the convergence of the vibration parameters of the fractured tibia to those of the unfractured contralateral. The conclusions obtained from curvature analysis, based on vibration experiments, were in considerable correlation (Spearman's rank correlation coefficient r = 0.93, p = 0.003) with the conclusions obtained from the three-point bending test data which reflected the mechanical condition of the bone by direct means. However, no correlation between bone mineral density change and vibration transmission was noted.

Animals↗