Inter-Reader Variability of Volumetric Subsolid Pulmonary Nodule Radiomic Features.

OBJECTIVE: To evaluate the inter-observer consistency for subsolid pulmonary nodule radiomic features. MATERIALS AND METHODS: Subsolid nodules were selected by reviewing radiology reports of CT examinations performed December 1, 2015 to April 1, 2016. Patients with CTs at two time points were included in this study. There were 55 patients with subsolid nodules, of whom 14 had two nodules. Of 69 subsolid nodules, 66 were persistent at the second time point, yielding 135 lesions for segmentation. Two thoracic radiologists and an imaging fellow segmented the lesions using a semi-automated volumetry algorithm (Syngo.via Vb20, Siemens). Coefficient of variation (CV) was used to assess consistency of 91 quantitative measures extracted from the subsolid nodule segmentations, including first and higher order texture features. The accuracy of segmentation was visually graded by an experienced thoracic radiologist. Influencing factors on radiomic feature consistency and segmentation accuracy were assessed using generalized estimating equation analyses and the Exact Mann-Whitney test. RESULTS: Mean patient age was 71 (38-93 years), with 39 women and 16 men. Mean nodule volume was 1.39mL, range .03-48.2mL, for 135 nodules. Several radiomic features showed high inter-reader consistency (CV<5%), including entropy, uniformity, sphericity, and spherical disproportion. Descriptors such as surface area and energy had low consistency across inter-reader segmentations (CV>10%). Nodule percent solid component and attenuation influenced inter-reader variability of some radiomic features. The presence of contrast did not significantly affect the consistency of subsolid nodule radiomic features. Near perfect segmentation, within 5% of actual nodule size, was achieved in 68% of segmentations, and very good segmentation, within 25% of actual nodule size, in 94%. Morphologic features including nodule margin and shape (each p <0.01), and presence of air bronchograms (p = 0.004), bubble lucencies (p = 0.02) and broad pleural contact (p < 0.01) significantly affected the probability of near perfect segmentation. Stroke angle (p = 0.001) and length (p < 0.001) also significantly influenced probability of near perfect segmentation. CONCLUSIONS: The inter-observer consistency of radiomic features for subsolid pulmonary nodules varies, with high consistency for several features, including sphericity, spherical disproportion, and first and higher order entropy, and normalized non-uniformity. Nodule morphology influences the consistency of subsolid nodule radiomic features, and the accuracy of subsolid nodule segmentation.

Customized Versus Noncustomized Sound Therapy for Treatment of Tinnitus: A Randomized Crossover Clinical Trial.

OBJECTIVES: To determine the effectiveness of a customized sound therapy and compare its effectiveness to that of masking with broadband noise. METHODS: Subjects were randomized to receive either customized sound therapy or broadband noise for 2 hours per day for 3 months and then switched to the other treatment after a washout period. The outcome variables were tinnitus loudness (scored 0-10), Tinnitus Handicap Inventory (THI), Beck Anxiety Inventory (BAI), minimum masking levels (MML), and residual inhibition (RI). RESULTS: Eighteen subjects completed the study. Mean age was 53 ± 11 years, and mean tinnitus duration was 118 ± 99 months. With customized sound therapy, mean loudness decreased from 6.4 ± 2.0 to 4.9 ± 1.9 ( P = .001), mean THI decreased from 42.8 ± 21.6 to 31.5 ± 20.3 ( P < .001), mean BAI decreased from 10.6 ± 10.9 to 8.3 ± 9.9 ( P = .01), and MML decreased from 22.3 ± 11.6 dB SL to 17.2 ± 10.6 dB SL ( P = .005). After 3 months of broadband noise therapy, only BAI and, to a lesser degree, MML decreased ( P = .003 and .04, respectively). CONCLUSIONS: Customized sound therapy can decrease the loudness and THI scores of tinnitus patients, and the results may be superior to broadband noise.

The prevalence and characteristics of tinnitus in the youth population of the United States.

OBJECTIVES/HYPOTHESIS: To evaluate the prevalence, characteristics, and associated risk factors of tinnitus in U.S. adolescents. STUDY DESIGN: Cross-sectional analyses of U.S. representative demographic and audiometric data, the National Health and Nutrition Examination Survey (NHANES) 2005 to 2008. METHODS: The study population consisted of 3,520 individuals aged 12 to 19 years with complete tinnitus-related data. Tinnitus was defined as the presence of ringing or buzzing in the ears lasting for at least 5 minutes during the preceding 12 months. In addition, we defined a chronic tinnitus subgroup as being bothered by tinnitus for more than 3 months. Demographic and other data regarding tinnitus, smoking, body mass index (BMI), anemia, hypertension, history of ear infections, tympanostomy tube placement, otoscopy, tympanometry and hearing thresholds, history of firearm use, and recreational and occupational exposure to noise were extracted and analyzed. RESULTS: Overall, tinnitus lasting 5 minutes or more in the preceding 12 months was reported by 7.5% of the 12- to 19-year-old population. This represents about 2.5 million adolescents in the United States. The prevalence of chronic tinnitus was 4.7%, corresponding to about 1.6 million adolescents in the United States. Multivariable-adjusted analysis revealed that both overall and chronic tinnitus were associated with female gender, low income, exposure to passive smoking, type A tympanogram, and occupational and recreational noise exposure. History of ≥ 3 ear infections and history of tympanostomy tube placement were associated only with overall tinnitus. CONCLUSIONS: Tinnitus afflicts a substantial portion of the youth population. Further investigation of the association between tinnitus and the identified risk factors is warranted.

Transcanal approach for implantation of a cochlear nerve electrode array.

OBJECTIVES/HYPOTHESIS: To evaluate a transcanal approach for placement of a stimulating electrode array in the cochlear nerve. STUDY DESIGN: Prospective cadaveric temporal bone study. METHODS: Ten human cadaveric temporal bones were dissected. Both a facial recess approach with mastoidectomy and a transcanal approach using the novel technique were performed in each bone. A middle fossa dissection of the internal auditory canal was performed to confirm the position of the electrode in the cochlear nerve. RESULTS: The transcanal approach offered a direct approach to the cochlear nerve in all 10 bones. The procedure was quicker than the facial recess approach and did not endanger the facial or chorda tympani nerves. Inspection of the medial end of the internal auditory canal confirmed correct placement of the electrode in the cochlear nerve. In contrast, anatomical constraints, specifically the position of the facial nerve, blocked access to the cochlear nerve by the facial recess approach in three of the specimens to achieve the exposure to place the electrode at a perpendicular angle to the cochlear nerve. Sacrifice of the chorda tympani was necessary in five of the seven bones in which the cochlear nerve could be accessed. CONCLUSIONS: The transcanal approach offers a simpler, safer approach for cochlear nerve implantation compared to the facial recess approach. This approach can be accomplished in less time and avoids the hazards of dissection around the facial nerve. Use of the proposed approach will facilitate development of intraneural stimulation for an improved auditory prosthesis.

Efficacy of commercial earplugs in preventing water intrusion during swimming.

OBJECTIVE: To evaluate and compare the efficacy of commercially available earplugs in preventing water intrusion in healthy individuals. STUDY DESIGN: Experimental study. SETTING: Tertiary care medical center. SUBJECTS AND METHODS: Ten subjects (20 ears) were assessed. After insertion of the earplugs, subjects underwent 3 standardized head-wetting protocols, including (1) surface swimming for 10 minutes, which entailed no head submersion and moderate splashing; (2) head submersion at a 90-cm depth for 20 seconds with their head upright; and (3) head submersion at a 90-cm depth with head tilted 90 degrees left and then tilted 90 degrees right for 10 seconds on each side to apply vertical pressure. Color change of a wetness indicator was used to determine water intrusion after each protocol. The same protocol was repeated for all 9 earplugs. RESULTS: Water intrusion was observed in 44%, 67%, and 88% of ears after surface swimming, horizontal submersion, and vertical submersion, respectively. The results revealed a significant difference in the waterproofing qualities of the various types of earplugs. The soft silicone type (Pillow Soft) earplug had the lowest rate of water penetration during all 3 protocols (P < .001). The difference between the most effective earplugs, Pillow Soft and Aquaseal, were only significant during the horizontal submersion protocol (P = .008). CONCLUSION: Water intrusion occurred even with the use of earplugs. The intrusion was more significant with horizontal or vertical head submersion. The soft silicone Pillow Soft earplug was the most effective earplug for preventing water intrusion in surface swimming.

Investigation of a novel completely-in-the-canal direct-drive hearing device: a temporal bone study.

HYPOTHESIS: Whether a prototype direct-drive hearing device (DHD) is effective in driving the tympanic membrane (TM) in a temporal bone specimen to enable it to potentially treat moderate-to-severe hearing loss. BACKGROUND: Patient satisfaction with air conduction hearing aids has been low because of sound distortion, occlusion effect, and feedback issues. Implantable hearing aids provide a higher quality sound but require surgery for placement. The DHD was designed to combine the ability of driving the ossicular chain with placement in the external auditory canal. METHODS: DHD is a 3.5-mm wide device that could fit entirely into the bony ear canal and directly drive the TM rather than use a speaker. A cadaveric temporal bone was prepared. The device developed in our laboratory was coupled to the external surface of the TM and against the malleus. Frequency sweeps between 300 Hz to 12 kHz were performed in 2 different coupling methods at 104 and 120 dB, and the DHD was driven with various levels of current. Displacements of the posterior crus of the stapes were measured using a laser Doppler vibrometer. RESULTS: The DHD showed a linear frequency response from 300 Hz to 12 kHz. Placement against the malleus showed higher amplitudes and lower power requirements than when the device was placed on the TM. CONCLUSION: DHD is a small completely-in-the-canal device that mechanically drives the TM. This novel device has a frequency output wider than most air conduction devices. Findings of the current study demonstrated that the DHD had the potential of being incorporated into a hearing aid in the future.

Posterior semicircular canal dehiscence following endolymphatic sac surgery.

Posterior semicircular canal dehiscence is a rare otologic entity that presents with third window signs and symptoms. Petrous apex cholesteatoma, fibrous dysplasia, high riding jugular bulb, and eosinophilic granuloma have been reported to be associated with posterior semicircular canal dehiscence. Here we report a case of development of posterior semicircular canal dehiscence following an endolymphatic sac surgery for the first time.

In vivo evaluation of focal lamina cribrosa defects in glaucoma.

OBJECTIVES: To assess focal lamina cribrosa (LC) defects in glaucoma using enhanced depth imaging optical coherence tomography and to investigate their spatial relationships with neuroretinal rim and visual field loss. METHODS: Serial horizontal and vertical enhanced depth imaging optical coherence tomographic images of the optic nerve head were obtained from healthy subjects and those with glaucoma. Focal LC defects defined as anterior laminar surface irregularity (diameter, >100 µm;depth, >30 µm) that violates the normal smooth curvilinear contour were investigated regarding their configurations and locations. Spatial consistency was evaluated among focal LC defects, neuroretinal rim thinning/notching, and visual field defects. RESULTS: Forty-six healthy subjects (92 eyes) and 31 subjects with glaucoma (45 eyes) were included. Ninety-eight focal LC defects representing various patterns and severity of laminar tissue loss were found in 34 eyes with glaucoma vs none in the healthy eyes. Seven of 11 eyes with glaucoma with no visible focal LC defect had a deeply excavated optic disc with poor LC visibility. Eleven focal LC defects presented clinically as an acquired pit of the optic nerve, and the others as neuroretinal rim thinning/notching. Focal LC defects preferably occurred in the inferior/inferotemporal far periphery of the LC including its insertion. Eyes with focal LC defects limited to the inferior half of the optic disc had greater sensitivity loss in the superior visual hemifield and vice versa. CONCLUSIONS: Mechanisms of LC deformation in glaucoma include focal loss of laminar beams, which may cause an acquired pit of the optic nerve in extreme cases.Focal LC defects occur in tandem with neuroretinal rim and visual field loss.

Horizontal central ridge of the lamina cribrosa and regional differences in laminar insertion in healthy subjects.

PURPOSE: To assess the general morphology and position of the lamina cribrosa (LC) in healthy subjects using enhanced depth imaging-optical coherence tomography (EDI-OCT). METHODS: Serial horizontal and vertical B-scans of the optic nerve head (interval between images, approximately 30 µm) were prospectively obtained using EDI-OCT for both eyes of each healthy subject. After delineation of the anterior laminar surface, mean and maximum LC depths were measured in 11 equally spaced horizontal B-scans, and the depth of the anterior LC insertion was measured at 32 points along its circumference (reference plane, Bruch's membrane edges) for one randomly selected eye of each subject. Three-dimensional (3D) images of the anterior laminar surface and the peripapillary sclera were reconstructed from serial horizontal EDI-OCT B-scans to assess the 3D morphology of the anterior laminar surface. RESULTS: Among the 61 eyes (61 subjects) enrolled, 31 were excluded because of poor LC image quality, and 30 were included for analysis (mean age, 40 ± 18 [range, 21-78] years). Both mean and maximum LC depth profiles showed an elevation in the central area and a depression in the superior and inferior midperiphery of the LC. The anterior LC insertion was more posteriorly located in the superior and inferior than in the nasal and temporal regions. Three-dimensional LC images showed a bowtie-shaped horizontal central ridge of the LC. CONCLUSIONS: The LC has a central ridge ranging from the temporal to the nasal insertion areas and inserts more posteriorly in the superior and inferior than in the nasal and temporal regions. Further investigation is needed to elucidate the significance of these findings in the pathophysiology of glaucoma.

Prevention and treatment of corneal neovascularization: comparison of different doses of subconjunctival bevacizumab with corticosteroid in experimental rats.

BACKGROUND: To evaluate and compare the effect of different doses of subconjunctival bevacizumab with betamethasone on the development of corneal major new vessels in a rat model of corneal chemical injury. METHODS: The right eyes of 100 male Sprague-Dawley rats were randomly divided into 10 experimental groups (n = 10 per group). Chemical cauterization of the cornea was performed by using silver nitrate/potassium nitrate sticks. Immediately following corneal cauterization, the animals in groups 1-5 received subconjunctival injections of 0.02 ml of normal saline (control A), betamethasone LA (6 mg/ml) and different doses of bevacizumab (1, 5 and 25 mg/ml), respectively. In another experiment, the animals in groups 6-10 received subconjunctival injections of 0.02 ml of normal saline (control B), betamethasone LA (6 mg/ml) and different doses of bevacizumab (1, 5 and 25 mg/ml), respectively, 7 days following corneal cauterization. The numbers of major thick-walled vessels originating from the limbus reaching the corneal scar were counted 7 days after corneal cauterization in groups 1-5 and 14 days after corneal cauterization in groups 6-10. RESULTS: The number of major vessels in groups 1-5 was 19.63 +/- 3.77, 17.25 +/- 5.33, 16.10 +/- 5.02, 12.89 +/- 2.70 and 12.36 +/- 4.45 when assessed 7 days after corneal cauterization, respectively. Administration of betamethasone in group 2 had no significant effect on the corneal major vessel count compared to control A. The number of major vessels in groups 4 and 5 (bevacizumab 5 and 25 mg/ml) was significantly lower than that of group 1 (p < 0.01, Student's t test). The number of vessels in groups 6-10 was 12.55 +/- 5.64, 11.30 +/- 9.33, 5.50 +/- 6.34, 2.73 +/- 4.73 and 2.67 +/- 3.77 when assessed 14 days after corneal cauterization, respectively. Subconjunctival administration of betamethasone 7 days after corneal cauterization did not reduce the amount of corneal major vessels compared to control B. Administration of 0.02 ml of bevacizumab in doses of 1, 5 and 25 mg/ml 7 days after corneal cauterization significantly reduced the amount of major vessels compared to group 6 (p = 0.01, p < 0.01 and p < 0.01, respectively). There was no significant difference in percent area of corneal scar between different groups. CONCLUSION: Single subconjunctival injection of bevacizumab is efficacious in the prevention of formation as well as regression of major vessels compared to betamethasone in this rat model of corneal neovascularization. Even lower doses of bevacizumab might be efficacious.

Effects of intravitreal morphine administered at different time points after reperfusion in a rabbit model of ischemic retinopathy.

PURPOSE: To investigate the effects of morphine administered after reperfusion in a rabbit model of ischemic retinopathy. METHODS: The right eyes of 54 albino New Zealand rabbits were randomly allocated into nine treatment groups (n = 6 in each group). The eyes in saline-control group received 0.1 mL of phosphate-buffered saline solution intravitreally. In the ischemia-saline group, ischemia was induced by raising the intraocular pressure to 150 mmHg for 60 minutes. Then 0.1 mL of phosphate-buffered saline solution was administered intravitreally 5 minutes after reperfusion. The eyes in three ischemia-morphine groups (ischemia-morphine 0 hour, 1 hour, and 18 hours) received 0.1 mL of morphine (10 micromol/L) intravitreally 5 minutes, 1 hour, or 18 hours after termination of 60 minutes of ischemia, respectively. The eyes in ischemia-naloxone-morphine group received 0.05 mL of naloxone (10 micromol/L) intravitreally followed by injection of 0.05 mL morphine (10 micromol/L) 5 minutes after termination of ischemia. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (10 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day. RESULTS: Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in ischemia-saline group compared with that of the saline-control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane (a measure of inner retinal thickness) was significantly increased due to edema (P < 0.001). Administration of morphine 5 minutes after reperfusion significantly improved all of the above mentioned indices compared with ischemia-saline group (P < 0.001). Administration of morphine 1 hour after reperfusion had also a significant effect on the improvement of above mentioned indices compared with saline-control group (P < 0.05). However, the number of ganglion cells was significantly higher in ischemia-morphine 0 hour group compared with ischemia-morphine 1 hour group (P < 0.001). Morphine treatment 18 hours after reperfusion did not change the amount of injury. Administration of naloxone 5 minutes before morphine abolished most of the morphine protective effects. CONCLUSION: Intravitreal administration of morphine immediately after reperfusion maximally protects retina against ischemia-reperfusion injury. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opioid receptors.

Role of endogenous cannabinoids in ischemia/reperfusion injury following testicular torsion in rats.

OBJECTIVES: The role of endogenous cannabinoids in ischemia/reperfusion induced germ cell apoptosis in rats was investigated. METHODS: Baseline group was for basal normal values. The Sham operated group served as a control group. The torsion/detorsion (T/D) group underwent torsion (1 h) and detorsion; AN1, AN2, and AN3 groups received anandamide (10 mg/kg) 30 min before torsion, 30 min after torsion, and just after detorsion, respectively. In the AM251 group, AM251 (0.5 mg/kg) was injected 45 min before torsion and in the AN/AM group, AM251 and anandamide were injected 45 and 30 min before torsion, respectively. Lipid peroxidation, antioxidant enzymes, and germ cell apoptosis was determined. RESULTS: Malondialdehyde (MDA) levels in the T/D group were significantly higher than the control group. Moreover, MDA values in the AN1, AN2, and AN3 groups were significantly lower than T/D. There were significant decreases in catalase and superoxide dismutase activities in the T/D group versus the control group. These values in the AN1, AN2, and AN3 groups were significantly higher than T/D. It was also shown that MDA levels in the AN/AM group were significantly higher than the AN1 group. In the AN/AM group, catalase and superoxide dismutase activities were significantly lower versus the AN1 group. The mean germ cell apoptosis scores in all animals with testicular T/D were significantly higher than the control group. There was no difference between the apoptotic indices in the AN1, AN2, AN3, and T/D groups. Apoptosis scores in AM251 and AN/AM were significantly higher compared with the T/D and AN1 groups. CONCLUSIONS: Although anandamide increased antioxidant markers, it failed to reduce germ cell apoptosis. AM251 worsened the antioxidant defense system, which is reflected as higher germ cell apoptosis.

Ethyl pyruvate reduces germ cell-specific apoptosis and oxidative stress in rat model of testicular torsion/detorsion.

PURPOSE: Testicular torsion/detorsion (T/D) results in enhanced formation of free radical metabolites, which contributes to the pathophysiology of tissue damage. We investigated the protective effects of ethyl pyruvate (EP) against testis tissue damage in an experimental model of testicular torsion. METHODS: Sprague-Dawley rats were divided into 5 groups. In those animals that underwent T/D, right testes were rotated 720 degrees for 1 hour. Group 1 control rats underwent sham operation. In group 2, the rats underwent T/D. The EP was prepared and injected in the form of Ringer's ethyl pyruvate solution. The rats in group 3, 4, and 5 received 2 doses of 20, 50, and 100 mg/kg EP (30 minutes before and after detorsion), respectively. The right testes of 6 animals from each group were excised 4 hours after detorsion for the measurement of lipid peroxidation, myeloperoxidase (MPO), and antioxidant enzymes activities. Germ cell apoptosis was determined in right testes of 8 animals per group 24 hours after detorsion. The epididymal sperm concentration and motility were evaluated 1 month after treatments. RESULTS: Germ cell apoptosis indices were significantly higher in group 2 compared with control group. The level of lipid peroxidation and MPO activity increased, whereas antioxidant enzymes activities decreased after T/D. Sperm count and motility were also reduced 1 month after T/D in group 2 rats. However, EP treatment at doses of 50 and 100 mg/kg significantly decreased the early apoptotic damage and improved long-term sperm count and motility. In the same dosing groups, we observed normalization of oxidant/antioxidant balance and decrement of MPO activity. However, administration of 20 mg/kg of EP conferred no protective effect. CONCLUSIONS: Administration of Ringer's ethyl pyruvate solution (in appropriate doses) is protective against apoptotic tissue damage following testicular torsion and improves long-term testicular function. The antioxidant and anti-inflammatory properties of EP seem responsible for the protective effects. Our findings suggest this resuscitation solution as a possible substitute for fluid and electrolyte maintenance during surgical detorsion.

Morphine pretreatment provides histologic protection against ischemia-reperfusion injury in rabbit retina.

PURPOSE: Pharmacologic preconditioning with morphine has been shown to protect several kinds of tissues against ischemia-reperfusion injury. The aim of the present study was to investigate whether intravitreal administration of morphine induces structural protection against ischemic damage in a rabbit model of ischemic retinopathy. METHODS: Twenty-eight male white New Zealand rabbits were used. Animals in saline control group received 0.1 mL of phosphate-buffered saline (PBS) intravitreally with no postinjection ischemia. In the saline-control ischemia group, 15 minutes after injection of PBS, retinal ischemia was induced by raising intraocular pressure to 150 mmHg for 60 minutes. In three treatment-ischemia groups, morphine (1, 5, and 10 micromol/L) was administered intravitreally 15 minutes before induction of ischemia. In another experiment, naloxone (40 micromol/L) was administered 5 minutes before intravitreal administration of morphine (10 micromol/L) followed by 60 minutes of ischemia to investigate the role of opioid receptors in mediating the possible protective effect of morphine. Toxicity controls were performed with morphine (10 micromol/L) and naloxone (40 micromol/L) without ischemia. Histologic evaluation was performed for all groups on the seventh postoperative day. RESULTS: Sixty minutes of ischemia led to severe cell loss in ganglion cell layer and thinning of the inner nuclear layer in saline-control ischemia compared to that of the nonischemia control group (P < 0.001). Thickness of the inner plexiform layer to the inner limiting membrane was significantly increased due to edema (P < 0.001). Administration of morphine in higher doses (5 and 10 micromol/L) significantly improved all of the above mentioned indices (P < 0.05). Administration of naloxone 15 minutes before morphine reversed most of the morphine protective effects. CONCLUSIONS: Morphine pretreatment provides significant histologic protection against ischemic injury in rabbit retina. Pharmacologic evidence suggests that this protective phenomenon may be mediated in part by opiate receptors.

Protective effects of sildenafil administration on testicular torsion/detorsion damage in rats.

PURPOSE: We assessed the effectiveness of sildenafil administration during ischemic period in a rat model of testicular torsion/detorsion (T/D). MATERIAL AND METHODS: Sprague-Dawley rats were divided into four groups (n = 10). In those animals that underwent T/D, right testes were rotated 720 degrees for 1 h. Base line group was for basal normal values. Sham operated group was served as a control group. T/D group underwent 1 h testicular torsion. Sildenafil group received sildenafil (0.7 mg/kg) intraperitoneally 30 min after initiation of ischemic period. For measurement of lipid peroxidation and antioxidant enzyme activities, right testes of five animals in each group were excised after 4-h reperfusion. Germ cell apoptosis indices were determined 24 h following detorsion in right testes of remaining five animals in each group. RESULTS: Malondialdehyde (MDA) levels in T/D group were significantly higher versus control and base line groups. Moreover, testicular MDA values in sildenafil group were significantly lower than T/D. There were also significant decreases in catalase and superxide dismutase activities in T/D group compared with control and base line groups. These values were significantly higher in sildenafil group versus T/D. Germ cell apoptosis indices were significantly higher in both groups that experienced T/D in comparison to control and base line groups; however, sildenafil treatment significantly reduced the apoptosis in sildenafil group compared with T/D group. CONCLUSION: Sildenafil administration during testicular torsion decreased ischemia/reperfusion cellular damage. The results of biochemical studies suggest that, reduction of oxidative stress by sildenafil may have a major role in its cytoprotective effects.

Salutary effects of N-acetylcysteine on apoptotic damage in a rat model of testicular torsion.

INTRODUCTION: Numerous studies performed in recent years have shown protective effects of N-acetylcysteine (NAC) on cardiac and renal tissue damage following ischemia/reperfusion injury. We assessed the effectiveness of systemic administration of NAC, at a therapeutic dose, in a rat model of a 1-hour 720-degree testicular torsion/detorsion. MATERIALS AND METHODS: Sprague-Dawley rats were divided into five groups, 14 animals in each: group 1 animals underwent sham operation as the control group; group 2 rats underwent torsion/detorsion and received saline injection, and the animals in groups 3, 4, and 5 received intraperitoneal injections of 150 mg/kg NAC 30 min before torsion, after torsion, and after detorsion, respectively. Markers of oxidative stress as well as germ cell apoptosis indices were assessed 4 and 24 h after detorsion, respectively. RESULTS: The apoptosis indices were significantly higher in group 2 as compared with the control group. Four hours after detorsion, the testicular level of lipid peroxidation was significantly increased, and antioxidant enzyme activities were significantly decreased in group 2 as compared with the controls. Administration of NAC either 30 min before or after torsion (groups 3 and 4) significantly improved the germ cell apoptosis indices and oxidant/antioxidant balance. Administration of NAC after detorsion had no significant effect on biochemical markers or germ cell apoptosis. CONCLUSION: Administration of NAC prior to torsion or detorsion, but not after detorsion, induces protective effects against ischemia/reperfusion injury in a rat model of testicular torsion.

Endogenous opioids modulate hepatocyte apoptosis in a rat model of chronic cholestasis: the role of oxidative stress.

AIMS/BACKGROUND: There are increasing number of evidences indicating the contribution of endogenous opioids in the pathophysiology of cholestatic liver disease. The aim of the present study was to determine the role of the endogenous-opioid system in the modulation of hepatocytes apoptosis and liver oxidant/anti-oxidant balance during chronic cholestasis in rats. METHODS: We induced cholestasis in rats by bile duct ligation (BDL). Naltrexone, an opioid antagonist, was administered at different doses (2.5, 5, 10, 20 and 40 mg/kg/day) to cholestatic animals for 5 weeks. RESULTS: Naltrexone prevented the cholestasis-induced decrease of hepatic glutathione levels at higher doses (20 and 40 mg/kg/day). In the next phase of the study, we evaluated the effects of 20 mg/kg/day naltrexone treatment on hepatic damage indices and liver oxidant/anti-oxidant balance in 5-week BDL rats. There was a marked increase in the number of apoptotic hepatocytes as well as serum liver enzymes and hepatic lipid peroxidation levels in cholestatic rats compared with sham-operated animals 5 weeks after the operation. Liver anti-oxidant enzyme activities were significantly reduced in cholestatic rats compared with controls. Chronic treatment with naltrexone significantly improved all the aforementioned indices in comparison with saline-treated cholestatic rats. CONCLUSION: Our findings demonstrate that the administration of opioid antagonist is protective against hepatic damage in a rat model of chronic cholestasis. We suggest that increased levels of endogenous opioids contribute to hepatocytes apoptosis in cholestasis, possibly through downregulation of liver anti-oxidant defense.

Chronic morphine treatment induces oxidant and apoptotic damage in the mice liver.

Recently many researchers have proposed a protective role for morphine against tumor growth and metastasis, especially through induction of apoptosis in tumoral cells. These findings may lead to underestimation of cytotoxic effects of opioid drugs which are usually expected only at high doses. The present study was conducted to clarify whether repeated morphine administration, which is commonly used for relief from chronic pain, would interfere with liver antioxidant defence and hepatocytes vitality. Morphine was injected repeatedly at doses that have been reported to relieve cancer pain and reduce tumor spread in mice (5 and 10 mg/kg/day for nine consecutive days). The changes in hepatic glutathione concentration, its synthesis pathway and enzymatic antioxidant defense revealed the pro-oxidant effects of chronic morphine treatment on the liver. None of these changes were observed in those mice that were co-treated with naltrexone (opioid antagonist) and same doses of morphine. However induction of liver conjugating enzymes following morphine treatment was not receptor mediated. Moreover, chronic morphine treatment induced hepatocytes apoptosis. Interestingly, the apoptotic changes were antagonized by co-administration of either naltrexone or thiol antioxidant. In conclusion, although hepatotoxic effects of morphine at high doses have been reported previously, our findings propose that repeated morphine administration even at lower doses would induce oxidative stress in the liver, which may contribute to induction of apoptosis in hepatocytes. Since many of the observed adverse effects were mediated by opioid receptors, our results suggest that other opioid analgesics should also be used more cautiously.

ATP-sensitive potassium channels mediate the anti-ischemic properties of ischemic and pharmacologic preconditioning in rat random-pattern skin flap.

Ischemic preconditioning (IPC) and pharmacologic preconditioning by morphine and adenosine may significantly decrease the amount of necrosis in rat random pattern skin flaps. We examined the role of ATP-sensitive potassium channels (K(ATP) channels) in mediating these protective phenomenon by using glibenclamide a nonspecific blocker of these channels. We also investigated whether administration of diazoxide an opener of the K(ATP) channels could mimic the same protective effect. Ninety male Sprague-Dawley rats were randomly divided into either control or treatment groups (n = 6 each). Bipedicled dorsal skin flaps (2 x 8 cm) were elevated at the midline. In pharmacologic preconditioning groups, 1 mL of morphine (5 mg/flap), adenosine (0.5 mg/flap), or different doses of diazoxide (0.5, 1, 5, and 15 mg/flap) were administered locally in the cranial half of the flap, respectively. One milliliter of saline was locally injected in the control group. In the IPC group, 1 hour after local saline injection the cranial pedicle was clamped for 20 minutes, and then 40 minutes' reperfusion was performed. In another experiment, 0.3 mg/kg of glibenclamide was injected intraperitoneally 30 minutes before local administration of saline or drug in ischemic or pharmacologic preconditioning groups. Regardless of the group, all flaps were cut at the cranial side 2 hours after elevation and were sutured back. Flap survival area was evaluated on the seventh postoperative day. IPC and pharmacologic preconditioning with morphine, adenosine, and diazoxide (in higher doses; 1, 5, and 15 mg/flap) improved survival area compared with the control group. Glibenclamide abolished their protective effect. K(ATP) channels may have a key role in anti-ischemic properties of IPC and pharmacologic preconditioning.