Biomedical subjects

Derya U Talas

Publications and source records attributed to Derya U Talas.

4 recordsLinked to original sources

PubMed2002

The effects of corticosteroids on the healing of tracheal anastomoses in a rat model.

The deleterious effects of corticosteroids on anastomotic healing have been widely demonstrated in various tissues. This study is designed to investigate the effects of corticosteroids on the healing of tracheal anastomoses. Forty-two adult female Wistar rats, randomly divided into five groups, underwent tracheal transection and primary anastomoses. The groups were assigned as follows: Group I, sham, ( N= 6); Group II, control, ( N= 6); Group III, dexamethasone, 0.1 mg kg (-1) per day, intramuscularly for a week ( N= 10); Group IV, dexamethasone, 1 mg kg (-1) per day, intramuscularly for a week (N= 10); Group V, dexamethasone, 6 mg kg (-1) intramuscularly as a single dose ( N= 10). After 7 days, anastomotic healing was assessed by measurement of bursting pressure and hydroxyproline content. Histological examination was performed according to the modified Ehrlich/Hunt scale. The bursting pressure was significantly decreased in Group III and Group IV when compared to the control group (P< 0.0001 for both groups). There was also significance between the bursting pressures of Group III and Group IV (P< 0.01). However, the difference failed to reach significance between Group V and the control group. The reduction of bursting pressure was not reflected in diminished hydroxyproline content. The hydroxyproline content of the study groups (GIII, GIV and GV) were not statistically different compared with the control group. Except for inflammatory cell infiltration, histological parameters including epithelial regeneration, fibroblast proliferation, collagen content, and angiogenesis also demonstrated significant differences among the groups (P< 0.05). The present study demonstrates that daily administration of dexamethasone for a week significantly impairs the healing of tracheal anastomoses in a dose-dependent manner while a single-dose postoperatively does not affect the healing process.

Adrenal Cortex Hormones↗

PubMed2002

The effects of dexamethasone on lipid peroxidation and nitric oxide levels on the healing of tracheal anastomoses: an experimental study in rats.

Corticosteroids are shown to have deleterious effects on wound healing for various tissues. Arginine metabolism and nitric oxide (NO) synthesis play an important role in many aspects of inflammation and wound healing. The study was designed to evaluate the relationship of dexamethasone impaired healing of tracheal anastomoses to NO metabolism and lipid peroxidation. Forty-two adult Wistar rats were randomly divided into five groups. The animals underwent tracheal transection and primary anastomoses. The groups were assigned as follows: Group I (GI) (sham, N = 6); Group II (GII) (control, N = 6); Group III (GIII), dexamethasone, 0.1 mg kg(-1) per day, intramuscularly for a week (N = 10); Group IV (GIV), dexamethasone, 1 mg kg(-1) per day, intramuscularly for a week (N = 10); Group V (GV), dexamethasone, 6 mg kg(-1) intramuscularly as a single dose (N = 10). After 7 days, bursting pressure was used to evaluate anastomotic healing. Serum nitrite/nitrate and malondialdehyde (MDA) levels were measured as an index of NO synthesis and lipid peroxidation, respectively. The bursting pressure significantly decreased in GIII and GIV when compared to the control group. The difference between GIII and GIV was also statistically significant. Nitrite/nitrate and MDA levels of GIII were found to be significantly higher than the control group. Also, the difference was found to be statistically significant between GIII and GIV in regard to nitrite/nitrate levels. The present study demonstrates that daily administration of dexamethasone for a week inhibits NO synthesis in a dose-dependent manner on tracheal anastomotic healing. Besides the generally accepted evaluation parameters including bursting pressure and hydoxyproline content; NO and MDA levels may be helpful in the assessment of wound healing especially for the investigation of impairment mechanism.

Anastomosis, Surgical↗

PubMed2002

Grisel's syndrome.

Summary Atlantoaxial subluxation is a rare complication of the upper neck inflammatory processes of head and neck region. Grisel's syndrome is a non-traumatic subluxation of the atlanto axial joint. It is not associated with trauma or bone disease. It typically occurs in children after serious infection in the head and neck region. Several theories have been proposed to explain the pathogenesis of inflammatory subluxation. The primary treatment of Grisel's syndrome is medical. We report a case of atlantoaxial rotatory subluxation treated with external fixation and antibiotic therapy.

Adult↗

PubMed2002

Frequency specificity of cochlear damage in acute electrical injury: a longitudinal distortion product otoacoustic emission study.

HYPOTHESIS: To understand cochlear dysfunction and the recovery pattern of the cochlea after acute electrical injury. BACKGROUND: The cochlea is believed to be more vulnerable to direct current than to alternating current. However, the damage-and frequency-specific recovery characteristics of the cochlea have not been well described. METHODS: Baseline distortion product otoacoustic emission measurements were taken via transtympanic electrodes from 19 guinea pigs. A 20-Hz alternating current and a positive direct current, both at a 1,000-microA intensity, were applied to 9 and 10 animals, respectively. The measurements were repeated immediately after the application of current and after 10 days. Comparisons were made for both groups individually in signal-to-noise ratios obtained before and immediately after, immediately and 10 days after, and before and 10 days after the application of electrical current. RESULTS: Alternating and direct currents caused a significant depression in signal-to-noise ratio immediately after the application. However, 10 days later, the mean signal-to-noise ratio in the animals subjected to alternating current came significantly close to the baseline value, particularly between the frequencies of 2,211 and 3,717 Hz. By contrast, the mean signal-to-noise ratio in the animals subjected to direct current remained significantly depressed throughout all frequencies except for 2,211 Hz. CONCLUSION: Baseline distortion product otoacoustic emission measurements enabled cochlear function to be monitored in a frequency-specific manner after electrical injury. The functional damages were quantitatively close to each other for both types of currents at a given intensity. Nevertheless, recovery was more apparent in the animals exposed to alternating current than in those exposed to direct current. Recovery was also better in the midfrequency region than in higher frequencies. It is hypothesized that the reason for the difference in recovery in both groups was the net charge left by direct current.

Acute Disease↗