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Biomedical subjects

Süleyman Kaplan

Publications and source records attributed to Süleyman Kaplan.

15 recordsLinked to original sources
PubMed2006

Protection of nigral cell death by bilateral subthalamic nucleus stimulation.

In Parkinson disease (PD), the subthalamic nucleus (STN) becomes hyperactive (disinhibited), which is reported to cause excitotoxic damage to midbrain dopaminergic neurons. Here, we examined whether silencing of the hyperactive STN by chronic bilateral deep brain stimulation (DBS) increased the survival of midbrain dopaminergic neurons in a rat model of PD. High-precision design-based stereologic examination of the total number of neurons and tyrosine tydroxylase (TH) immunoreactive neurons in the substantia nigra pars compacta revealed that STN DBS resulted in a significant survival of these neurons. These data provide the first evidence in vivo that bilateral STN DBS is useful for protecting midbrain dopaminergic neurons from cell death in PD.

Adrenergic Agents↗
PubMed2006

Cortical anastomotic veins occlusion in the rat including the assessment of cerebral swelling.

A rat model composed of the sacrifice of the anterior and posterior cortical anastomotic veins by microsurgical techniques was used for the assessment of brain swelling. Twenty male, 15-week-old Sprague-Dawley rats were used in this animal experiment. Small burr-holes were made over the anterior (the intersection of the line drawn from the posterior border of the orbital rim and the line drawn along the para-midline to the superior sagittal suture) and posterior (inferior point of the posterior end of the zygomatic arch) anastomotic veins. After performing a final inspection and describing the venous vessels, they were sacrificed using bipolar coagulation technique and micro-scissors. Specimens were evaluated using histopathological approach, albumin immunostaining technique and a stereological method. Hemispheric swelling, midline shift, brain oedema, subcortical petechial haemorrhagia, ischemia and necrosis were histopathological findings observed in this experimental study. The albumin immunostaining study demonstrated disrupted areas of the blood-brain barrier in the operated hemisphere. Stereological volumetric analysis revealed an 8% brain swelling in the operated hemispheres compared with unoperated ones. Our results suggest that the sacrifice of the anterior and posterior anastomotic veins may be used as an experimental rat model in the evaluation of brain damage and swelling caused by the occlusion of the venous anastomotic outflow.

Albumins↗
PubMed2006

Effect of a high fat diet on quantitative features of adipocytes in the omentum: an experimental, stereological and ultrastructural study.

BACKGROUND: Omental adipose tissue specimens of female rats that were fed a high fat (HF) diet were evaluated stereologically and histopathologically. To our knowledge, there is no stereological study on numerical density, nuclear height and volume of adipocytes in omental adipose tissue in the female rat fed a HF diet in the literature. METHOD: 20 female Spraque Dawley rats were used in the study. 10 of the animals were fed HF diet consisting of 30% of calories from fat for 3 months. The remaining 10 rats, the control group, were fed a normal diet. After the experimental procedure, all animals were anesthetized and omental adipose tissues in the same area were dissected and fixed for the histochemical process using a mixture of 3% glutaraldehyde and 1% osmium tetraoxide in 0.1 M phosphate buffer. After embedding of tissues in araldite CY 212, semi-thin and thin sections were cut. The semi-thin sections were stained with toluidine blue. The physical dissector counting method was used for estimation of numerical density and nuclear height of adipocytes. Cavalieri principle was used for the estimation of adipocyte volume; volume fraction approach was applied to find the volume fraction of adipose tissue components. RESULTS: The mean numerical density of adipocytes in the HF diet group was significantly higher than the control. The mean nuclear height of adipocytes was also very high in the HF diet group. The volume fraction of adipose mass was increased whereas the extracellular matrix volume fraction was reduced in the HF diet group compared to the controls. The mean volume of adipocytes in the HF diet group was also significantly higher than in the control group. At the light microscopy level, it was found that adipocytes were enlarged and gaining irregular shape in the HF diet group. Thicker basal lamina and electron dense lipid content were also found in this group at the electron microscopy level. CONCLUSION: Lipid content and number of adipocytes in the adipose tissue of HF diet rats were higher than in the controls. Thus, HF diet induces increase in body weight via both hypertrophy and hyperplasia of adipocytes.

Adipocytes↗
PubMed2005

Neonatal pinealectomy induces Purkinje cell loss in the cerebellum of the chick: a stereological study.

Melatonin plays an important role in certain physiological functions and morphological features of various structures. In the current study, the effects of pinealectomy on Purkinje cell number and morphological features of developing cerebellum in the chick were investigated using stereological methods. Fifteen Hybro Broiler newly hatched chicks were divided into three groups: a pinealectomized group (n = 5), sham-operated group (n = 5) and a non-pinealectomized control group (n = 5). Surgical pinealectomy was performed in 3-day-old chicks. In the 8th week, all animals were sacrificed for histopathological evaluation and subsequent stereological analysis. Each layer volume of molecular (+Purkinje cell), granular and white matter in the cerebellum was estimated in all animals. It was found that there was no significant difference for the volume of whole cerebellum and also molecular (+Purkinje cell) layer in these groups (P > 0.05). Nevertheless, the values of granular layer and white matter of sham-operated group were significantly different from those of control and pinealectomized animals (P < 0.01). It was also observed that pinealectomy significantly reduces the Purkinje cell number in cerebellar cortex (P < 0.01). The present study is the first stereological study to demonstrate the histomorphological effects of pinealectomy on the cerebellum in the chick. Our results suggest that pineal gland/melatonin might play an important role in morphological features of the developing cerebellum in the chick.

Animals↗
PubMed2005

Morphological alterations produced by zinc deficiency in rat sciatic nerve: a histological, electron microscopic, and stereological study.

Zinc (Zn) is an essential trace element for humans and animals. It is required for normal growth, gene expression, wound healing, protein metabolism, immune function, and membrane integrity. In this study, unbiased stereological methods have been used to quantify the effects of Zn deficiency on the sectioned surface area and the number of myelinated axons in the sciatic nerve of rats. Animals were fed a Zn-deficient or Zn-sufficient diet for a period of 4 weeks. At the end of this time, the samples of sciatic nerves were removed from the animals, processed for electron microscopy and embedded in resin. The Zn-deficient group of rats was found to have a lower body weight compared to rats in the control group (P < 0.05). The sectioned surface area of nerve cross-section and myelinated axon number in Zn-deficient rats decreased by 20% and 29%, respectively, compared to the control group. A significant correlation between sectioned surface area and myelinated axon number was also determined. Morphological findings were as follows: on light microscopy, it was determined that certain abnormalities occur specifically in the experimental group, such as collapsed nerve fascicles, irregular profiles of and degeneration in myelin sheaths, and on electron microscopy, extensive myelin damage was seen in Zn-deficient groups compared with control groups. This study suggests that peripheral nerves require Zn for development and preservation of their structure.

Animals↗
PubMed2005

A simple technique for localizing consecutive fields for disector pairs in light microscopy: application to neuron counting in rabbit spinal cord following spinal cord injury.

Locating the same microscopic fields in consecutive sections is important in stereological analysis. The tools for achieving this requirement have limited number in practice. This paper presents a simple and inexpensive technique for localizing the same fields on disector pairs in conventional light microscopes equipped with widely available dial indicators. It is partly a modification of equipment previously described. The presented procedure requires two light microscopes equipped with dial indicators and modified slide clips. An application of the present system was shown in a model of spinal cord injury (SCI). A midthoracic laminectomy was performed leaving the dura intact. A contusion was done at the level of midthoracic spinal cord segments (T7-T8) by dropping a 10-g mass from a height of 30 cm. The subjects were randomly divided into three groups (10 animals in each): hypothermia group, methylprednisolone group, and traumatic spinal cord injury alone group. Present results show that treatment with hypothermia after spinal cord trauma has a neuroprotective effect on cell damage but not in the methylprednisolone treatment group.

Animals↗
PubMed2005

Pinealectomy exaggerates and melatonin treatment suppresses neuroma formation of transected sciatic nerve in rats: gross morphological, histological and stereological analysis.

At present, an intensive effort for prevention of neuroma formation following peripheral nerve section continues. It has been recently suggested that surgical pinealectomy (Px) induces elevation of the collagen content in the granulation tissue of a wound, while melatonin application after Px suppresses elevation of the collagen accumulation in the tissue. The aim of the present study was to assess whether melatonin had the ability to suppress collagen production and neuroma formation following peripheral nerve transection. A total of 40 male rats (four groups of 10) were left intact (intact controls) or sham operated (sham group), were Px, or were Px and given melatonin (Px + melatonin group). All animals underwent a surgical intervention consisting of right sciatic nerve neurectomy. After 4 wk, the animals were killed following intracardiac perfusion. Gross morphology of neuroma formation in the proximal nerve segment was examined and proximal neuroma evaluated. Macroscopic and microscopic findings revealed that Px caused a proliferation of connective tissue and large neuroma formation at the proximal ends of transected nerves. Stereological analysis showed that there was a statistically significant reduction in connective tissue content of the same region in Px animals treated with melatonin (P < 0.005). The results achieved in a rodent model of sciatic nerve neuroma formation showed that there was a positive correlation between macroscopic and microscopic observations, and that melatonin enhanced axonal regeneration presumably due to its inhibitory effect on neuroma formation.

Animals↗
PubMed2005

Morphological, stereological and radiological changes in pinealectomized chicken cervical vertebrae.

Considerable evidence supports the hypothesis that melatonin plays an important role in osteogenesis. We carried out an experiment to investigate histological and radiological changes in the cervical vertebrae of pinealectomized chickens. Thirty new-hatched chicks were divided into two groups: pinealectomized group (n=15) and nonpinealectomized control (n=15). Surgical pinealectomies were performed in Hybro broiler chickens at the age of 3 days. At 8 wk, one animal from each group was examined using computed tomography scanner to obtain density histograms of four consecutive vertebrae between the 4th and 7th cervical vertebral segments of chickens. At the end of the study, all animals were killed for subsequent measurement of bone mineral density (BMD) and macroscopic, radiographic and histopathological evaluation of specimens. We found that the profile of the density histogram in nonpinealectomized control group showed a spike profile for the vertebral body, indicating an increase in the amount of higher density tissues in this region, while a plateau-shaped profile was obtained for the vertebral body in pinealectomy group, indicating the presence of heterogenous bone tissue. Accordingly, the mean value of BMD in pinealectomy group was significantly lower at the vertebral body in chickens compared with control subjects (P<0.001). At the end of the experiment, almost all of the chickens in pinealectomy group developed a scoliotic curvature and the mean weight and length of the cervical vertebral bodies of the pinealectomized chickens were significantly lower than those of control group (P<0.001). Although the numerical density of osteocytes and osteoblasts in pinealectomy group was significantly higher than that from the control group, total number of osteocytes but not osteoblasts in cervical vetrebrae from pinealectomized animals was significantly lower than that from nonpinealectomized control animals (P<0.05). In conclusion, the results of the current study demonstrated for the first time pinealectomy-induced histomorphometrical changes in chicken vertebral column using stereological methods, suggesting that pineal gland/melatonin may have an osteoinductive effect on bone formation, but further studies are needed to elucidate the relationship of our findings with some disorders such as postmenopausal and/or senile osteoporosis.

Animals↗
PubMed2004

Enhancement of nerve regeneration and orientation across a gap with a nerve graft within a vein conduit graft: a functional, stereological, and electrophysiological study.

In this study, the right sciatic nerves of 40 rats were used to determine whether a nerve graft within a vein graft might accelerate and facilitate axonal regeneration, compared with a nerve graft alone. The animals were separated into four groups, as follows: group 1, sham control; group 2 (control), segmental nerve resection and no repair; group 3, segmental nerve resection and nerve grafting; group 4, segmental nerve resection and reconstruction with a nerve graft within a vein conduit graft. For all groups, sciatic functional indices were calculated before the operation and on postoperative days 7 and 90. On postoperative day 90, the sciatic nerves were reexposed and nerve conduction velocities were recorded. The sciatic nerves were harvested from all groups for counting of the myelinated axons with a stereological method. No statistically significant differences with respect to return of gait function, axon count, or nerve conduction were noted between groups 3 and 4 (p > 0.05). However, functional recovery in group 4 on postoperative day 90 was significant, compared with group 2 (p < 0.05); the recovery difference between groups 2 and 3 was not significant (p > 0.05). This study was not able to demonstrate any functional benefits with the use of a nerve graft within a vein graft, compared with standard nerve grafting.

Animals↗
PubMed2004

Use of longitudinal invaginating matrix sutures in microarterial sleeve anastomoses.

A different approach to end in end anastomosis was tested to minimise the undesirable traits of classic and sleeve (telescoping) methods. Our approach aimed to maintain full contact at the level of the anastomosis by using longitudinal matrix sutures as a new invaginating suture technique in microarterial sleeve anastomosis. Classic end-to-end anastomosis with seven to eight stitches, Lauritzen's end-in-end anastomosis with four stitches, and our modified end-in-end anastomosis with two horizontal matrix sutures were made in 10, 20, and 25 rat femoral arteries, respectively. Nine, 17, and 18, respectively were patent at early evaluation; and eight, 13, and 14 at the time of late evaluation. There was no significant difference in between the patency rates of the groups. Histopathological examination showed large strictures and the formation of intra-luminal organised thrombus with thin intramural fibrin precipitation in occluded specimens. The longitudinal matrix sutures in the sleeve anastomoses, which passed through all layers of the vascular wall, injured the intima (a vertical rupture) and constricted the lumen.

Anastomosis, Surgical↗
PubMed2003

Unbiased estimation of the liver volume by the Cavalieri principle using magnetic resonance images.

OBJECTIVE: It is often useful to know the exact volume of the liver, such as in monitoring the effects of a disease, treatment, dieting regime, training program or surgical application. Some non-invasive methodologies have been previously described which estimate the volume of the liver. However, these preliminary techniques need special software or skilled performers and they are not ideal for daily use in clinical practice. Here, we describe a simple, accurate and practical technique for estimating liver volume without changing the routine magnetic resonance imaging scanning procedure. MATERIALS AND METHODS: In this study, five normal livers, obtained from cadavers, were scanned by 0.5 T MR machine, in horizontal and sagittal planes. The consecutive sections, in 10 mm thickness, were used to estimate the whole volume of the liver by means of the Cavalieri principle. The volume estimations were done by three different performers to evaluate the reproducibility. RESULTS: There are no statistical differences between the performers and real liver volumes (P > 0.05). There is also high correlation between the estimates of performers and the real liver volume (r = 0.993). CONCLUSION: We conclude that the combination of MR imaging with the Cavalieri principle is a non-invasive, direct and unbiased technique that can be safely applied to estimate liver volume with a very moderate workload per individual.

Cadaver↗
PubMed2003

Rapid estimation of the vertebral body volume: a combination of the Cavalieri principle and computed tomography images.

OBJECTIVE: The exact volume of the vertebral body is necessary for the evaluation, treatment and surgical application of related vertebral body. Thereby, the volume changes of the vertebral body are monitored, such as infectious diseases of vertebra and traumatic or non-traumatic fractures and deformities of the spine. Several studies have been conducted for the assessment of the vertebral body size based on the evaluation of the different criteria of the spine using different techniques. However, we have not found any detailed study in the literature describing the combination of the Cavalieri principle and vertebral body volume estimation. MATERIALS AND METHODS: In the present study we describe a rapid, simple, accurate and practical technique for estimating the volume of vertebral body. Two specimens were taken from the cadavers including ten lumbar vertebras and were scanned in axial, sagittal and coronal section planes by a computed tomography (CT) machine. The consecutive sections in 5 and 3 mm thicknesses were used to estimate the total volume of the vertebral bodies by means of the Cavalieri principle. Furthermore, to evaluate inter-observer differences the volume estimations were carried out by three performers. RESULTS: There were no significant differences between the performers' estimates and real volumes of the vertebral bodies (P>0.05) and also between the performers' volume estimates (P>0.05). The section thickness and the section plains did not affect the accuracy of the estimates (P>0.05). A high correlation was seen between the estimates of performers and the real volumes of the vertebral bodies (r=0.881). CONCLUSION: We concluded that the combination of CT scanning with the Cavalieri principle is a direct and accurate technique that can be safely applied to estimate the volume of the vertebral body with the mean of 5 min and 11 s workload per vertebra.

Body Weights and Measures↗
PubMed2002

Estimation of numerical density and mean synaptic height in chick hippocampus 24 and 48 hours after passive avoidance training.

The effects of passive avoidance learning on synaptic morphology and number in the dorsolateral hippocampus of chick were investigated at 24 and 48 h after training. Chicks of both sexes were used. The numerical density of synapses and mean synaptic height were determined using design-based quantitative electron microscopic techniques. Our results suggest that after training there is a significant increase in synaptic density in the dorsolateral hippocampus of chicks at both 24 and 48 h, and also that the mean synaptic height was significantly different between trained and control groups. The increase in synaptic density was due to shaft (type II) synapses. It is known that during synaptogenesis, shaft synapses are formed first and are then converted to spine synapses. The only hemispheric asymmetry was found in the 24 h water-trained (W-trained) males where the numerical density of spine synapses was significantly higher in the left hippocampus. No significant differences due to gender in either numerical synaptic density or synapse height were observed at either 24 and 48 h. Comparison of the 24 h with 48 h groups showed an increase in shaft synaptic density over time in the W-trained groups, and an increased density of both shaft and spine synapses with time in methylanthranilate-trained (MeA-trained) chicks. These results demonstrate that the dorsolateral hippocampus of the chick shows synaptic changes at both 24 and 48 h after training and implicates this region in the long-term memory process.

Aging↗
PubMed2002

Sex differences and right-left asymmetries in rat hippocampal components.

Previous reports have indicated morphologic hippocampal asymmetry in thickness in male and female rats. In the present study, the possible sex differences and right-left asymmetries in rat hippocampal components were investigated. Pyramidal cells in four hippocampal sectors on thionin-stained sections were counted and the thickness of the hippocampal components was measured on microslide-projected images. The present study showed significant sexual dimorphism in two hippocampi as well as asymmetry in male. These findings agree with those found in humans.

Animals↗