Amikacin-induced acute renal injury in rats: protective role of melatonin

It is well established that some agents such as aminoglycosides generate free oxygen radicals, leading to an increased oxireductase production, which in turn increases tissue toxicity. The aim of this study is to test whether melatonin, the chief secretory product of the pineal gland and a highly effective antioxidant and free radical scavenger, reduces the nephrotoxicity caused by amikacin (AK). Herein, we investigated the physiologic and pharmacological role of melatonin in influencing AK-induced nephrotoxicity. For this, pinealectomized (Px) and sham operated (non-Px) rats were used. Both AK and melatonin were administered to all groups. We investigated the effects of melatonin on AK-induced changes in levels of malondialdehyde (MDA), a lipid peroxidation product, glutathione (GSH), an antioxidant whose levels are influenced by oxidative stress, and blood urea nitrogen (BUN) and serum creatine (Cr) levels. Morphologic changes in the kidney were also examined by using light microscopy. MDA levels were found to be higher in Px than in non-Px AK-treated animals. Melatonin administration to Px rats reduced MDA levels. In relative to non-Px rats, Px animals treated with AK had significantly lower GSH concentrations while melatonin administration elevated GSH levels in the kidney; however, this stimulatory effect of melatonin was not observed in non-Px AK-treated rats. Treatment with AK alone resulted in significantly higher plasma Cr and BUN levels. Repeated administration of melatonin prevented the AK-induced elevation of plasma Cr and BUN levels. Morphologic damage to renal tubules as a result of AK was more severe in the renal cortex than in the medulla. The damage to the kidney induced by AK was reversed by melatonin in the Px rats. In conclusion, these results show that physiologic melatonin concentrations are important in reducing AK-induced renal damage, while pharmacologic concentrations of melatonin did not add to the beneficial effect.     

Extralobar pulmonary sequestration mimicking neuroblastoma

Extralobar pulmonary sequestration is a congenital pulmonary malformation, which rarely may be present in an intra-abdominal location. We describe a 1-week-old newborn with an intra-abdominal sequestration, which presented to us as an antenatally diagnosed suprarenal mass. Intra-abdominal extralobar sequestration should also be kept in differential diagnosis in cases of masses in the suprarenal location.     

Three-Dimensional Measurements of the Nasal Interdomal Fat Pad

The interdomal fat pad (IFP) is an important structure related to tip deformity in rhinoplasty. This study aimed to evaluate the IFP by ultrasonography before surgery, and to demonstrate the existence of the IFP as a distinct anatomic structure in cadavers and patients. Three dimensions of the IFP were measured in 23 patients using ultrasound before rhinoplasty and in 10 cadavers using dissection. All fat pads were examined by histopathologic methods. In the cadavers, three dimensions of the IFP were found: 2.3 × 3.7 × 12.8 mm. In the patients, three dimensions of IFP were measured by ultrasonography: 2.8 × 4.1 × 13.7 mm. Histopathologic examinations showed that the IFP is a structure differentiated from subcutaneous tissue. The IFP was demonstrated in all cadavers and patients by surgical and radiologic methods. All cases had a fat pad in the interdomal space with varying sizes.     

Increased gray matter density in the parietal cortex of mathematicians: a voxel-based morphometry study

BACKGROUND AND PURPOSE: The training to acquire or practicing to perform a skill, which may lead to structural changes in the brain, is called experience-dependent structural plasticity. The main purpose of this cross-sectional study was to investigate the presence of experience-dependent structural plasticity in mathematicians' brains, which may develop after long-term practice of mathematic thinking. MATERIALS AND METHODS: Twenty-six volunteer mathematicians, who have been working as academicians, were enrolled in the study. We applied an optimized method of voxel-based morphometry in the mathematicians and the age- and sex-matched control subjects. We assessed the gray and white matter density differences in mathematicians and the control subjects. Moreover, the correlation between the cortical density and the time spent as an academician was investigated. RESULTS: We found that cortical gray matter density in the left inferior frontal and bilateral inferior parietal lobules of the mathematicians were significantly increased compared with the control subjects. Furthermore, increase in gray matter density in the right inferior parietal lobule of the mathematicians was strongly correlated with the time spent as an academician (r = 0.84; P < .01). Left-inferior frontal and bilateral parietal regions are involved in arithmetic processing. Inferior parietal regions are also involved in high-level mathematic thinking, which requires visuospatial imagery, such as mental creation and manipulation of 3D objects. CONCLUSION: The voxel-based morphometric analysis of mathematicians' brains revealed increased gray matter density in the cortical regions related to mathematic thinking. The correlation between cortical density increase and the time spent as an academician suggests experience-dependent structural plasticity in mathematicians' brains.     

The effect of melatonin on 7,12-dimethyl-benz[a]anthracene injury in comparison with vitamin E + selenium in mouse kidneys

The aims of this study were to observe the changes in antioxidative defense enzymes and renal morphology after 7,12-dimethyl-benz[a]anthracene (7,12-DMBA) administration in mice and to investigate the possible protective effects of melatonin against 7,12-DMBA-induced renal damage in comparison with vitamin E + selenium (vit E + Se). Forty female mice were divided into four groups: control, DMBA, DMBA + vit E + Se and DMBA + melatonin. In the DMBA group, mice were given injections of 7,12-DMBA (20 mg/kg). DMBA + vit E + Se group mice received injections of 7,12-DMBA + vit E + Se (20 mg/kg + 90 mg/kg + 1.8 microg/kg). In the melatonin group, mice were given injections of 7,12-DMBA + melatonin (20 mg/kg + 4.2 mg/kg). The experiment lasted for 21 days. Mice were killed and the kidneys were taken for enzyme analyses and histologic examination. Catalase (CAT) and glutathione peroxidase (GSH-Px) activities were found significantly decreased in the DMBA group and in the DMBA + vit E + Se group when compared with the control group (P < 0.05), whereas CAT and GSH-Px activities were found significantly elevated in the DMBA + melatonin group when compared with the control (P < 0.05) and the DMBA group (P < 0.01). Exposure to DMBA resulted in tubular alterations in renal cortex. Morphometric analysis revealed proximal and distal tubular damage (P < 0.05). These alterations were found to be prevented by melatonin but not with vit E + Se administration. These results reveal that melatonin stimulates CAT and GSH-Px activities and prevents renal injury better than vit E + Se combination in mice kidneys.     

Efficacy of melatonin as protectant against oxidative stress and structural changes in liver tissue in pinealectomized rats

Previous observations demonstrated that physiological levels of melatonin, the pineal secretory product, are important in protecting against oxidative stress-induced tissue damage. We investigated the effects of pinealectomy and administration of exogenous melatonin on liver tissue in rats. Pinealectomized (Px) and sham-operated (non-Px) rats were used. We evaluated structural changes, reduced glutathione (GSH) levels and malondialdehyde (MDA) levels. Rats were divided into three groups (10 rats in each group): control (non-Px), Px+vehicle and Px+melatonin (4 mg/kg given daily intraperitoneally for 10 days). Liver GSH levels were significantly lower in Px rats than in the control group. Melatonin administration significantly increased GSH levels (p < 0.05). Px caused a significant increase in MDA levels as compared with the control group and melatonin administration to Px rats significantly reduced MDA levels in the liver (p < 0.05). Sinusoidal dilatation to a varying degree developed in all Px rats. Severity of mononuclear cell infiltration and sinusoidal congestion were lower in Px+melatonin group than in the Px group. These findings suggest that a significant increase in oxidative and structural changes occur in rat livers after pinealectomy, which can be diminished by melatonin treatment.     

An atypical case of Sjögren's syndrome causing unilateral severe lacrimal gland enlargement and hypoglobus

We report the first case of Sj?gren's syndrome causing gross lacrimal gland swelling and secondary hypoglobus and uncharacteristically absent sicca syndrome. Histopathological diagnosis of the excision biopsy of the orbital lobe of the gland confirmed a mixed T and B cell infiltrate of the gland with no lymphomatous transformation. The condition remains quiescent following complete excision.