The influence of functional pinealectomy and exogenous melatonin application on healing of burr hole in adult rat calvaria: a histological and immunohistochemical study

Background: Even today, repair of the cranial defects still represents a significant challenge in neurosurgery and various options have been used for their reconstruction to date. but there are very few studies investigating the effects of exogenous administration of melatonin (MEL) as an agent that promotes bone regeneration. The goal of this study was to investigate the effects of functional pinealectomy (Px) and exogenous MEL administration on the bone repair properties and surrounding connective tissue alterations in a rat calvaria model. Materials and methods: The total of 30 adult female Wistar-Albino rats was randomly divided into three groups (n = 10): control (CO) group (12 h light/12 h dark exposure), functional Px group (24 h light exposure, light-induced functional Px), and Px+MEL group (light-induced Px plus MEL, 20 mg/kg/day for 12 weeks). Critical-sized burr-hole defects (diameter = 3.0 mm) were surgically created by a single operator in the calvarium of all rats, using an electric drill. Animals in Px+MEL group received MEL 20 mg/kg/day for 12 weeks. At the end of the study, bone healing and connective tissue alterations surrounding drilled defect area in the rat calvaria were determined in hematoxylin/eosin-stained and mallory azan slices applied in anti-bone sialoprotein (BSP). Image Pro Express 4.5 program was used for histomorphometric calculation of areas of new bone and fibrotic tissue. Normality control was performed by Shapiro Wilk test. Variance homogeneities were examined by Shapiro Wilk and Levene tests; Tukey HSD test was used as a post hoc method since there was no homogeneity problem. All hypothesis tests were performed at the 0.05 significance level. Results: Histological analysis showed that the bone repair process in the Px+MEL group was similar to that of the CO group, whereas the functional Px group showed a delay. Histomorphometrically, it was found that the Px group had the largest hole diameter and the most fibrotic scar area, although no binary statistical significance was found between the CO and Px+MEL groups (p=0.910). In terms of vascularization, it was observed that the most vascular structure was found in the Px+MEL group among the scar tissue and ossification areas, while the vascularization was the least in the Px group (p < 0.001). Conclusions: Our findings revealed that bone repair process was impaired in functional Px group, but exogenous MEL replacement was able to restore this response. Thus, it is concluded that utilization of MEL may improve the bone repair in calvarial defects

Exactly solvable quantum Sturm-Liouville problems

The harmonic oscillator with time-dependent parameters covers a broad spectrum of physical problems from quantum transport, quantum optics, and quantum information to cosmology. Several methods have been developed to quantize this fundamental system, such as the path integral method, the Lewis-Riesenfeld time invariant method, the evolution operator or dynamical symmetry method, etc. In all these methods, solution of the quantum problem is given in terms of the classical one. However, only few exactly solvable problems of the last one, such as the damped oscillator or the Caldirola-Kanai model, have been treated. The goal of the present paper is to introduce a wide class of exactly solvable quantum models in terms of the Sturm-Liouville problem for classical orthogonal polynomials. This allows us to solve exactly the corresponding quantum parametric oscillators with specific damping and frequency dependence, which can be considered as quantum Sturm-Liouville problems

Neuroprotective effects of preischemia subcutaneous magnesium sulfate in transient cerebral ischemia

PubMed ID: 9726620Objective: Neurological injury due to transient cerebral ischemia is a potential complication of cardiovascular surgery. The neuroprotective effect of magnesium, when given subcutaneously before the ischemia, was assessed in a rat model of transient global cerebral ischemia. Methods: Thirty-six male Wistar albino rats were included to this randomized, controlled, prospective study. In 24 animals, ischemia was induced with four-vessel occlusion technique with the duration of 15 min. MgSO4 was given 600 mg/kg subcutaneously 48 h before the procedure in group 1 (n = 12). Similar volume of saline solution was used in animals of control group (group 2, n = 12). The animals in group 3 (sham group, n = 12) were anesthetized and subjected to operative dissections without vascular occlusion. Physiological parameters and somatosensory evoked-potentials (SEP) were monitored in animals before ischemia, during ischemia and in the first 30 min of reperfusion. Their neurological outcome had been clinically evaluated and scored up to 4 days postischemia. The intergroup differences were compared. Then the animals were sacrificed and their brains were processed for histopathological examination. Results: In group 3, SEP amplitudes did not change during the procedures, and all animals recovered without neurologic deficits. At the end of ischemic period, the average amplitude was reduced to 5 ± 3% of the baseline in all ischemic animals. This was followed by a gradual return to 87 ± 10% and 83 ± 8% of the initial amplitude after 30 min of reperfusion in group 1 and group 2, respectively (P > 0.05). The average neurological score was significantly higher in group 1 than in group 2 at 48, 72 and 96 h after the ischemic insult (P < 0.05). Histological observations were clearly correlated with the neurological findings. Conclusion: The results suggest that subcutaneous MgSO4 reduces cerebral injury and preserves neurologic function when given two days before the transient global ischemia in rats

Boron containing polyvinyl alcohol/ polyethylene oxide/polyvinyl pyrrolidone composites: Preparation, characterization, gamma radiation shielding and gamma radiation effect on it's thermal properties

The production of PVA/PEO/PVP-B4C and PVA/PEO/PVP-BN nanocomposites is presented in this study by adding certain proportions of boron nitride (BN) and boron carbide (B4C) to the polyvinyl alcohol(PVA)/polyethylene Oxide (PEO)/polyvinyl pyrrolidone (PVP) blend. The percentages of BN and B4C nano powder in the PVA/PEO/PVP blend have been determined as 5%, 10% and 20%. Thermal characterizations were carried out with different techniques such as Differential scanning calorimetry (DSC), Differential Thermal Analysis (DTA), Thermogravimetry (TG). Surface, crystal structure and atomic percentage distribution analyzes of the obtained composites were performed by X-ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction Analysis (XRD), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), and elemental analysis. 10 kGy gamma irradiation was performed on PVA/PEO/PVP-B4C and PVA/PEO/PVP-BN composites. The thermal behavior of the composites at this dose level was investigated. In addition, the radiation shielding properties of composite films obtained at 10 cm distances using Am-241 beam source were examined. © 2023 Elsevier LtdThis study was supported by project number 118C578 under the TÜBİTAK 2218-National Postdoctoral Research Fellowship Program

A case report of OGILVIE'S syndrome in an ischemic stroke patient [Iskemik serebral enfarktüs sonrasi gelişen OGILVIE sendromu olgusu]

Acute colonic pseudo-obstruction (ACPO), also known as Ogilvie's Syndrome, is a clinical condition with acute dilatation of the colon without a provable cause. Early recognition and treatment of the condition is important in order to improve the outcome(1). An 86 year old right handed male patient, with an acute ischemic infarction in the area supplied by the right middle cerebral artery (MCA) anterior divison, was internalised to our intensive care unit of Neurology Department. Seventeen days after onset of the stroke, the patient, whose vitals, blood electrolite levels and oxygene saturation kept stabile developed an abdominal distention. He didn't have any fecal excretion for 2 days and his rectum was found to be empty on the rectal touche' examination. His lateral decubit abdominal x-rays were suspicious for sigmoid volvulus. His abdominal CT was also suspicious for mesoaxial volvulus, so the patient underwent a colonoscopy at the gastro enterology department. The colonoscope has reached the hepatic flexure but no volvulus has been observed. As the result of the colonoscopy the patient is diagnosed as acute colonic pseudoobstruction(Ogilvie's Syndrome). With conservative treatment, fecal excretion has been provided in 24 hours. Here, we want to take attention that, Ogilvie's syndrome, in which early diagnosis and treatment decreases mortality and morbidity rates, can also be seen in stroke patients and is one of the emergent situations which should be kept in mind for stroke patients who have abdominal distention and constipation