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Biomedical subjects

S Akin

Publications and source records attributed to S Akin.

18 recordsLinked to original sources
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↗
PubMed2002

One-stage treatment of chronic osteomyelitis of the proximal tibia using a pedicled vascularised double-barrel fibular flap together with a muscle flap.

Although segmental bone loss together with a soft-tissue defect after debridement of a chronic osteomyelitic lesion of the tibia represents a challenging problem for the reconstructive surgeon, bone management has not usually been carried out at the time of soft-tissue coverage. In a one-stage procedure, we treated a patient who had suffered from chronic osteomyelitis of the tibia for 12 years, using a pedicled vascularised double-barrel fibular flap together with a pedicled medial gastrocnemius muscle flap, immediately after radical debridement of the osteomyelitic lesion. Bony union was obtained at 4 months. Full unprotected weight-bearing for normal walking was achieved 10 months after fibular transfer. Follow-up at 2 years showed no recurrence of the osteomyelitis.

Aged↗
PubMed2001

Burned ear reconstruction using a prefabricated free radial forearm flap.

Postauricular skin, postauricular fascia, temporoparietal fascia (pedicle or free), the free radial forearm flap (fascial or fasciocutaneous), and free lateral arm fascial flap, have been used for burned ear reconstruction reported in the literature. Patients who did not have normal tissue around the ear region, because of severe thermal injuries to the external ear, are not available for draping the costal cartilage framework; these patients require free flaps. The author reports a burned ear reconstruction, using a prefabricated free radial forearm fasciocutaneous flap, included an autogenous costal cartilage framework. In this case, the front and back of the cartilage framework were covered with the skin of the forearm flap. This is the main difference from other techniques in the literature. This flap is valuable for burned ear reconstruction, when local tissue and other free flaps are not available.

Burns↗
PubMed2001

Microvascular free on-top plasty in a mutilated hand.

Amputation of the index, middle, and ring fingers leaves a poor, unstable pinch and grasp between the thumb and little finger. In this type of mutilated hand, it is necessary to reconstruct one or two fingers for firm chuck pinch and good grasp. Functionally and cosmetically, toe transfer is superior to other methods of finger reconstruction because of its mobility, sensibility, pulp size, and nail availability. However, a transfer from the foot may not always be available. In such a case, any finger stump may be considered as a possible donor finger. The authors performed a microvascular free transfer of the remaining portion of the ring finger including the metacarpophalangeal joint to the top of the remaining portion of the index finger in a mutilated hand with intact thumb and little finger because the patient declined toe transfer. Postoperatively, more effective strength and stability, provided by three converging digits, was achieved in the hand. Accordingly, it was easier for the patient to grip small and large objects. The authors describe this procedure as a microvascular free on-top plasty.

Adult↗
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↗
PubMed2000

Penetration of the pulp chamber by bleaching agents in teeth restored with various restorative materials.

It is thought that externally applied bleaching agents may penetrate into the pulp chamber. This study was conducted to evaluate the diffusion of peroxide bleaching agents into the pulp chamber of teeth restored with various restorative materials. Sixty-five human extracted anterior maxillary teeth were separated into the 13 groups containing 5 teeth. Five teeth (control group) were not subjected to any cavity preparation and restoration. Standardized class V cavities were prepared in the other 60 teeth and restored using composite resin (Charisma), polyacid modified composite resin (Dyract), or resin-modified glass ionomer cement (Vitremer). All teeth were sectioned 3 mm apical to the cementoenamel junction to remove the intracoronal pulp tissue, and the pulp chamber was filled with acetate buffer to absorb and stabilize any peroxide that might penetrate. Vestibular crown surfaces of teeth in the experimental groups were subjected to four different bleaching agents for 30 min at 37 degrees C, whereas the teeth in the control groups were exposed only to distilled water. Then the acetate buffer solution in the pulp chamber of each tooth was removed, and the pulp chamber of each tooth was rinsed with 100 ml of distilled water twice. Leukocrystal violet and enzyme horseradish peroxidase were added to the mixture of the acetate buffer and rinse water. The optical density of the resulting blue solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. Higher hydrogen peroxide concentrations resulted in a higher pulpal peroxide penetration. The highest pulpal peroxide penetration was found in resin-modified glass ionomer cement groups, whereas composite resin groups showed the lowest pulpal peroxide penetration.

Acetates↗
PubMed1999

Salvage of the lower leg using a reversed long free fibular flap.

The advantages of end-to-side anastomoses have been well documented in microvascular surgery. The vessels of the fibular flap do not usually permit end-to-side anastomosis to recipient vessels in the proximal part of the lower leg because the pedicle length of the free fibular flap is usually too short. Therefore, vein grafts are used to elongate the vessels. If a harvested long free fibular flap that is used to bridge a massive defect of the tibia is reversed and placed into the medullary cavity of the tibia, the flap vessels can be anastomosed, using the end-to-side technique, to the recipient vessels without vein grafts in the distal part of the lower leg. Thus, the flap artery (the peroneal artery) fills in a retrograde fashion. The patient reported was reconstructed with a reversed long free fibular flap. The postoperative period was uneventful. The patient can stand and walk with a protective shoe 2 years postoperatively.

Anastomosis, Surgical↗
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↗
PubMed1997

A new flap from the dorsum of the first intermetacarpal area: the first dorsal intermetacarpal flap.

Soft-tissue reconstruction of the hand still remains a challenge for plastic and reconstructive surgeons. Several flaps have been described to cover soft-tissue defects of the digits and the hand. In the first web region, there are some communications between the intermediate artery arising from the dorsal branch of the radial artery and the volar arteries of the thumb and the index finger. Depending on these communications, a new distally based flap is raised from the first dorsal intermetacarpal area. This flap has been used to cover various defects of the thumb in four patients and the distal radial side of the palmar area in one patient. Donor sites have been closed primarily except in one patient. There were no complications, and the results show that this flap is useful to cover soft-tissue defects of the thumb and proximal phalanx of the index finger as well as the radial side of the palmar and dorsal surfaces of the hand.

Adolescent↗
PubMed1996

The role of brain acetylcholine in GABAA receptor antagonist-induced blood-pressure changes in rat.

Previous experimental studies have shown that intracerebroventricular (i.c.v.) injection of the GABAA receptor antagonist, bicuculline methiodide, results in marked increases in blood pressure due to an increase in sympathetic nervous system activity. It is well recognized that the central cholinergic system is also involved in the regulation of blood pressure. In the present study, we examined the role of brain acetylcholine in the pressor response induced by bicuculline methiodide in conscious Sprague-Dawley rats. I.c.v. (0.05, 0.3 and 0.5 nmol) and intrahypothalamic (40 pmol) administration of bicuculline methiodide produced blood-pressure increases in a dose-dependent manner. Hemicholinium-3 was given i.c.v. 1 h prior to bicuculline methiodide. The depletion of brain acetylcholine was demonstrated by the suppression of physostigmine-induced pressor responses, but blood pressure increases in response to carbachol remained unchanged. The pressor responses to bicuculline methiodide in animals pre-treated with hemicholinium-3 were significantly higher than those seen in saline-pre-treated groups. Likewise, bicuculline methiodide, at a dose that did not alter blood pressure alone, caused pressor responses in rats pre-treated with the nicotinic receptor antagonist, mecamylamine, whereas the muscarinic receptor antagonist, atropine, was ineffective in this respect. In conclusion, it seems likely that endogenous brain acetylcholine has a modulator role on GABAA receptor-mediated blood-pressure control via nicotinic receptors.

Acetylcholine↗
PubMed1996

The second dorsal metacarpal artery flap with double pivot points.

A flap with double pivot points based on the second dorsal metacarpal artery was used in 13 cases with no complete failures. In 2 cases, the branches of the radial nerve were included in the flap. In 1 case, the flap was used as a tenocutaneous flap with a segment of the extensor indicis proprius tendon. To obtain a flap with double pivot points, the dissection of the vascular pedicle of a distally based second dorsal metacarpal flap is continued proximally under the second dorsal metacarpal artery up to its origin. In this flap the main pivot point coincides with the origin of the SDMA and the second pivot point with the entry point of the recurrent cutaneous branch into the flap. We found this flap to be very versatile, reliable, and quite easy and quick to raise. We report our experience with this flap as a very useful addition to reconstructive procedures, especially for thumb defects.

Adolescent↗
PubMed1993

Sympathetic skin response and R-R interval variation in rheumatoid arthritis. Two simple tests for the assessment of autonomic function.

Autonomic nervous system involvement with peripheral neuropathy is a well known complication of rheumatoid arthritis (RA). In the assessment of autonomic function of patients with rheumatoid arthritis, we performed sympathetic skin response (SSR) and R-R interval variation (RRIV) tests in 30 patients and in 30 normal controls. Of 30 patients, 5 had complaints of clinical dysautonomic symptoms. SSRs were abnormal in 6 of 30 patients, whereas 8 showed abnormal RRIVs during deep breathing. Nine of 30 patients also showed electrophysiologic evidence of peripheral neuropathy. All 5 of the patients with clinical dysautonomic symptoms showed abnormal SSR and RRIV test results. No patients with normal results on both tests had clinical dysautonomia. This study showed that there are frequent abnormalities in SSR and RRIV tests in patients with rheumatoid arthritis whether there is a clinical symptom of autonomic dysfunction or not.

Action Potentials↗
PubMed1987

Determination of immune status in patients with low antibody titers for rubella virus.

Three assays for detection of rubella antibodies, Rubella G (fluorescence immunoassay [FIA]), Rubacell (passive hemagglutination), and Rubaquick (passive hemagglutination with rotation), were compared with hemagglutination inhibition. A total of 100 serum specimens were selected, 68 of which had an FIA value of less than or equal to 25. On initial testing, among the four tests, there was agreement for 88 specimens for assignment of rubella immune status. On repeat testing, all the results agreed by the hemagglutination inhibition, passive hemagglutination, and passive hemagglutination rotation methods, and only one discrepant specimen remained by FIA.

Antibodies, Viral↗