Experimental trigeminal glycerol injection in dogs: histopathological evaluation by light and electron microscopy.

We investigated the effects of percutaneous gasserian glycerol injection in dogs and reviewed the histopathological changes. Experiments were performed in 16 adult healthy mongrel dogs. In group 1 (8 dogs) normal saline and in group 2 (8 dogs) pure glycerol was injected in the right trigeminal ganglion. After these procedures, dogs in each group were sacrificed after 24 h (3 dogs), 7 days (3 dogs), 21 days (2 dogs). The trigeminal ganglion and nerve of both sides were removed by using microsurgical techniques and examined by light and electron microscopy. Group 1: in all sections, nerve cells, myelinated and nonmyelinated fibers revealed normal patterns with slight fibrosis. Group 2: in all sections, myelinated fibers showed disintegration and swelling of the myelin sheath, rupture of axon continuity, destruction of basal lamina, deformation of the myelin-axon relationship by both light microscopy and electron microscopy. The sections examined by electron microscopy also showed axonolysis in nonmyelinated fibers. The changes after 7 and 21 days were less prominent than after 24 h. In the left sides, there are no pathological changes. Glycerol has a neurolytic effect on the dog's trigeminal ganglion. These effects were not specific and selective for myelinated and nonmyelinated nerve fibers.

The effect of tizanidine on chronic vasospasm in rats.

BACKGROUND: Cerebral vasospasm after subarachnoid hemorrhage (SAH) has remained a major cause of morbidity and mortality in patients with SAH. Excitatory neurotransmitters are gathered in the extracellular space during ischemia due to cerebral vasospasm and initiate or stimulate a series of pathophysiological biochemical processes which consequently lead to neuronal death. Tizanidine (Sandoz compound DS 103-282, 5-chloro-4,2 (2-imidazolin-2-yl-amino)-2,1,3-benzothiazol hydrochloride) is a centrally-acting muscle relaxant and a selective alpha 2 adrenoreceptor agonist which shows its effect by stimulating presynaptic alpha 2 adrenoreceptors in central ASPergic and GLUergic system by inhibiting aspartic acid and glutamic acid release. In this study, the effect of Tizanidine on vasospasm was evaluated. METHODS: We used a femoral artery vasospasm model in rats which has been described by Okada et al. 60 rats were examined in three groups. The first group was used as control group (Control) (n = 20), in the second group subarachnoid hemorrhage was performed (SAH) (n = 20), in the third group Tizanidine was administered in addition to SAH (SAH + Tizanidine administration) (n = 20). Animals in SAH + Tizanidine administration group received 0.3 mg/kg/day intraperitoneally for 7 days. Seven days after the experiment, after perfusion-fixation, 10 mm segments of both femoral arteries were removed and the femoral artery was prepared for light microscope examination, scanning and transmission electron microscopy and for morphometric analysis. RESULTS: There was a statistically significant difference between the electron, scanning and light microscopic observations and morphometric analysis of SAH + Tizanidine administration group and SAH group, and no statistically significant difference between SAH + Tizanidine administration group and control group. CONCLUSION: This study has disclosed that Tizanidine administration before the vasospasm reduces ultrastructural and morphometric vasospastic insult significantly. However, the clinical application of Tizanidine as a protective and therapeutic agent in cerebral vasospasm needs further studies including the employment of clinically more relevant SAH models.

Neurotransmitter and amino acid analysis and ultrastructural observations of fetal brain cortex transplantation to adult rat brain under the effect of dexamethasone.

OBJECTIVE: To conduct an investigation of fetal cortical tissue graft survival using transmission electron microscopy and analyzing neurotransmitters and amino acids and their function, with special reference to the effect of dexamethasone. METHODS: Transplantation of fetal cortical brain tissue to 100 adult Wistar albino rats weighing 170 to 220 g was performed. The rats were divided into three groups. Only transplantation of fetal cortical brain tissue was performed in the first group (n=36). In the second group (n=48), dexamethasone was administered in addition to fetal cortical tissue transplantation. The third group (n=16) was used as the surgical control group. The rats were allowed to live for 6 weeks and were then decapitated. The grafts were examined by electron microscopy. Additionally, quantitative analyses of the neurotransmitters and amino acids of the grafts were conducted using high-pressure liquid chromatography. RESULTS: Electron microscopic observations revealed that the grafts were still surviving at the end of the 6th week in both groups. However, in the group that received dexamethasone, neurons and their organelles were better developed than in the group that did not receive dexamethasone. Concommitantly, results of quantitative analysis in the dexamethasone group revealed statistically extremely significant higher amino acid values for glutamic acid, aspartic acid, beta-alanine, and lysine and significantly higher values for gamma-aminobutyric acid, glutamine, glycine, and serine when compared to the nondexamethasone group. CONCLUSION: Dexamethasone is effective in increasing the survival and in developing the ultrastructural and functional outcome of transplanted neurons in fetal grafts.

The fine structure of normal and ectopic (tubal) human placental villi as revealed by scanning and transmission electron microscopy.

The aim of this study was to examine the development of chorionic villous trees during early periods of normal intrauterinal and ectopic (tubal) pregnancies, and to study the structural specializations on the free surface of mature placental villi by scanning and transmission electron microscope (SEM and TEM). In order to study the structures of placental villi between 28 and 34 days old (pc), early, 6-8 week normal and ectopic, and full term human placenta samples were obtained from legal curettage and hysterectomized cases, and spontaneous deliveries, and tissues samples were prepared for SEM and TEM. Three-dimensional configurations of the developing chorionic villous trees were observed as large main villus groups, covered with abundant microvilli of different size and diameters. It appeared that the chorionic villous trees which emerged from the chorionic plate divided gradually into branches of which ramifications originated as buds. These buds gradually grew and were transformed into shoots. The number of developing new villi appeared to increase gradually from 28 days to 9 weeks (pm) of gestation. From the 4th week onwards the massive trophoblastic sprouts were observed on the surface of main chorionic villi which transformed into primary, secondary and tertiary villous trees. When the placental villi formation in ectopic pregnancy was compared with the intra-uterinal pregnancy, an arrested development was remarkable. The configurations of ectopic placental villi seemed to be disparate, such as curved lines or compressed and wrinkled positions so that the three dimensional aspect had been wizened. The ramification and new villi formation seen as in the normal placenta were not only decreased but also infrequent. Some placental villi samples displayed a gradually thinning terminal region. Trophoblastic degenerations were frequently found on the surface of ectopic villi ultrastructurally. According to these results, we comment that in ectopic pregnancy the placental villi formation and development could have been delayed. At term, some specialized structural modifications were observed on the free surface of the mature placental villi. The presence of some dome-like balloonings and many crateriform hollows were the most striking features of the mature intermediate and terminal villi. According to the increasing physiological needs of the growing fetus, these special structures that are related to lung-like and kidney-like functions and named "nephropneumonic-like units", formed in the mature placental barrier. We have observed that these special units were showing a smooth surface similar to an inflated balloon.(ABSTRACT TRUNCATED AT 400 WORDS)

Angiotensin-converting enzyme inhibitor cilazapril prevents chronic morphologic vasospasm in rat.

It has been shown that a long-acting angiotensin-converting enzyme inhibitor cilazapril prevents morphologic changes in arteries secondary to hypertension and endothelial damage, which are analogous to the changes in cerebral arteries following subarachnoid hemorrhage. In this study, the effect of cilazapril on chronic vasospasm was investigated on the rat femoral artery vasospasm model, and morphometric analyses were performed. Animals were divided into three groups. In group 1, femoral arteries were removed after cardiac perfusion. In groups 2 and 3, right femoral arteries were exposed to 0.1 mL autologous whole blood and wrapped with silastic cuff. Animals in group 3 received cilazapril (10 mg/kg) for 7 consecutive days. After the perfusion-fixation, femoral arteries were examined by light and transmission electron microscopy and processed for morphometric analysis. Vessels from animals in group 2 showed a significant luminal narrowing and morphologic changes throughout the vessel wall, while vessels from animals treated with cilazapril appeared nearly normal. These results suggest that cilazapril may be effective in the prevention of chronic vasospasm.

Preventive effect of intracisternal heparin for proliferative angiopathy after experimental subarachnoid haemorrhage in rats.

Proliferative angiopathy represents the morphological basis of delayed cerebral vasospasm. The initial vasoconstriction and endothelial damage of the vasospastic arteries leads to an exaggerated response of the smooth muscle cells within the media leading to subintimal thickening and myonecrosis. Heparin reduces the exposure of the media to platelet derived growth factor, a mitogen from aggregating platelets responsible for the migration and proliferation of the myofibroblasts. Since systemic heparin in the setting of a subarachnoid haemorrhage would be unacceptable, we have tested the effect of heparin on proliferative angiopathy by injecting autologous non-heparinized blood into two groups of rats (N = 12 each) and then inject the heparin into the spinal fluid of one group after one hour. We were able to show histologically that intracisternal heparin injection after the subarachnoid haemorrhage has reduced the vascular wall changes to a great degree. Heparinization of the cerebrospinal fluid carried out in conjunction with early operation for aneurysms may be a promising approach to prevent the morbid complications of SAH in the clinical setting.

Efficacy of ampicillin/sulbactam combination in experimental shunt infections caused by Staphylococcus epidermidis. A light and scanning electron microscope study.

In this study, the efficacy of ampicillin/sulbactam combination in reactions of periventricular tissue of the lateral ventricle induced by the presence of infected (Staphylococcus epidermidis) silicone rubber shunt tubing was examined by using light and scanning electron microscopy. It was demonstrated that reactive changes to implants had occurred in periventricular tissue in the control group. In infected shunt tubing without given prophylactic antibiotic group, generalized meningitis and ventriculitis, loss of integrity of ependymal cells, numerous inflammatory cells, bacterial colonies, exuda and even pus were seen. It was also shown that rarely inflammatory reactions, minimal disintegration of ependymal cells, no bacterial colonies, and phagocytes were present in the group which was given prophylactic ampicillin/sulbactam combination per and postoperatively. We think that ampicillin/sulbactam combination is very effective in prevention and treatment of shunt infections.

Ultrastructural observations on the entry of Chlamydia trachomatis into human spermatozoa.

Chlamydia trachomatis infections are an important problem in human reproduction and family planning. In this study, the significance of chlamydial infection in male infertility and artificial insemination has been investigated. Electron microscope observations on male ejaculates have revealed the presence of the elementary and reticulate body forms of C.trachomatis in spermatozoa. Furthermore, the entry of the elementary body into the human spermatozoon head has been demonstrated. After the passage of the infectious elementary body into the nucleus, all stages of reticulate body formation in the head of the spermatozoon were detected. According to ultrastructural findings, C.trachomatis not only adhered to but also penetrated into the tail structure. Thus two different functional and morphological forms of C.trachomatis can infect and be transmitted by spermatozoa and may cause infertility.

Magnetic resonance imaging in the diagnosis of idiopathic giant-cell granulomatous hypophysitis: a rare cause of hyperprolactinaemia.

Idiopathic giant cell granulomatous hypophysitis is a rare disorder of pituitary gland characterised by a chronic inflammatory process. It can also be an extremely rare cause of hyperprolactinaemia. In this paper, we present our experience with two cases of idiopathic giant cell granulomatous hypophysitis manifested by hyperprolactinaemia, and their neuroradiological evaluation including preoperative MRI studies in one of them, and discuss our findings in the light of the literature.

Topical effect of bromocriptine on rat-transplanted human prolactinomas.

In prolactinoma surgery, especially in macro-adenomas, it is not always possible to remove the tumour totally. Cell remnants may cause a regrowth and continue hypersecretion. In order to find out whether tumour remnants could be destroyed by local application of bromocriptine, a research model has been designed. First, prolactin secreting pituitary tumours, removed during surgery, were implanted bilaterally into the brain tissue of rats. In eight rats, the viability of tumour transplants was proven histopathologically and their prolactin secretion was shown immunocytochemically. In a second step, on eight rats, sterile bromocriptine solution was applied topically to the tumour transplants on one side. The other side served as control. Histopathological examination of these treated tissues revealed fibrosis. Immunocytochemical analysis showed no secretory activity. Ultrastructural investigations also revealed evidence of degeneration of the treated cells. The natural course of the transplanted tumour tissues of the other side, as a control group, was also observed during the same 55-day period.

Reaction of rabbit lateral periventricular tissue to non-infected and infected (Staphylococcus epidermidis) shunt tubing implants. A light and transmission electron microscope study.

The reactions of periventricular tissue of the lateral ventricle to non-infected and infected (Staphylococcus Epidermidis) silicone shunt tubing were examined by light and transmission electron microscopy. It was shown that reactive changes occurred in periventricular tissue in response to the implant of sterile shunt tubing. On the other hand in infected implanted silicone shunt tubing, proliferation of inflammatory cells within the ventricle and periventricular tissue, loss of integrity of the ependyma, glial cell proliferation, and excessive extracellular oedema were demonstrated. Proliferation of ependymal cells combined with inflammatory responses may be a factor in the pathogenesis of infected shunt obstruction.

Suppression of atherogenesis by n-3 fatty acids in the cholesterol-fed rabbit.

The effects of n-3 fatty-acid supplementation on serum lipids, platelet aggregation, and the development of atherosclerotic lesions were studied in the cholesterol-fed rabbit. Serum total cholesterol and LDL cholesterol values were significantly reduced in comparison with those of the nonsupplemented cholesterol-fed group (p less than 0.005, p less than 0.0025, respectively), though still higher than those of the control group (p less than 0.0025, p less than 0.0125 respectively). Platelet aggregation was reduced below that of the cholesterol-fed and the control levels (p less than 0.0005, p less than 0.0025, respectively). The endothelial injury encountered in cholesterol-fed rabbits was inhibited in the supplemented group. It is concluded that n-3 fatty acids suppress atherogenesis in this animal model by interfering with platelet aggregation and lipid metabolism.

Acute idiopathic demyelinating polyneuropathy: passive transfer to mice by immunoglobulin.

Systemic administration of acute idiopathic demyelinating polyneuropathy (AIDP) immunoglobulins to mice for two weeks resulted in reduced sural nerve action potential amplitudes and reduced (rotarod) motor performance. Electron microscopic examination of the sciatic nerves of the AIDP-immunoglobulin-treated animals revealed loosening of myelin lamellae with widening of interperiod lines and multivesicular disruption of myelin. Vacuolar degeneration was detected in half of the nerves examined by light microscopy. Injection of AIDP-immunoglobulins for three days led to only minor changes, and mice receiving healthy human immunoglobulins showed no abnormalities. These data show that some features of AIDP can be transferred to mice by systemic administration of immunoglobulins and suggest that humoral factors have a pathogenic role in AIDP in addition to cellular factors.

Improved survival of transplanted cortical brain tissue grafts by iloprost in rats.

The cytoprotective effect of iloprost on the viability and survival of embryonic cortical brain tissue grafts was examined ultrastructurally under light and electron microscopy before and 4 weeks after transplantation surgery. It was shown that neural grafts stored in iloprost solution (50 ng/mL) for 3 hours were more or less in a normal cytoarchitecture compared with saline-preserved grafts. Moreover, it was demonstrated that 4 weeks after transplantation, graft tissues stored in iloprost solution for 3 hours before implantation maintained a successful survival. Thus, a higher cellular population with new vascularization areas and preservation of myelin formation were accepted as a desirable integration of the graft tissue into the host brain tissue. The mechanism of action of iloprost is discussed.

Cytoprotective effect of iloprost on isolated cortical brain tissue grafts in rats.

The cytoprotective effect of iloprost was studied on isolated embryonic cortical brain tissue grafts of rats, using light and transmission electronmicroscopy. The brain tissue pieces were stored either in saline or 50 ng/ml iloprost solution for 30 minutes, 3, 6, 24 hours at +4 degrees C. It was demonstrated that iloprost significantly protected the neuronal integration of the tissue pieces compared with saline preserved pieces. Tissues preserved in iloprost showed only minimal dissolution of the tissue with minimal extracellular edema only in the later stages of preservation. The mechanism of action of the cytoprotective effect of iloprost is discussed.

Fetal vasculogenesis and angiogenesis in human placental villi.

Placental villi of 5 exactly defined early human specimens ranging from day 21 post conception (p.c.) until day 42 p.c. and from an additional 43 specimens from about 5 to 40 weeks menstrual age have been analyzed ultrastructurally with regard to fetal vasculogenesis and angiogenesis. The following results were obtained: The first cells differentiating at day 21 p.c., probably originating from mesenchymal precursors, are macrophage-like cells. At almost the same time, mesenchymal cells transform into haemangioblastic cell cords which are the forerunners of the capillary endothelium and haematopoietic stem cells. A third cell population related to the fetal circulatory system and derived from the mesenchymal cells are presumptive pericytes. Capillary formation takes place by the aggregation of haemangioblastic cells which are attached to each other by intercellular junctions. The lumen is formed by the dehiscence of the intercellular clefts. A capillary basal lamina cannot be detected earlier than in the last trimester. In this last period of gestation, fetal villous angiogenesis takes place by the proliferation of the existing endothelium and pericytes rather than via haemangioblastic cells.

Congenital insensitivity to pain with anyhydrosis: morphological studies of skin and peripheral nerves.

Two male siblings born to consanguineous parents, with the diagnosis of congenital insensitivity to pain with anhydrosis are evaluated. The patients presented with unexplained bouts of fever, self-mutilation, repeated trauma and inability to sweat. Physical examination revealed both siblings to be insensitive to pain and temperature. The electron microscopic study of the skin was unremarkable whereas sural nerve biopsies yielded an essential lack of unmyelinated fibers.

Fetal pituitary transplants into the hypothalamic area of hypophysectomized rats.

The pituitary tissue, when transplanted to extracerebral sites other than the normal anatomic position, fails to perform its secretory function properly. Several works on experimental intracerebral pituitary transplantation have shown that the transplanted tissue has been able to survive histologically. In this study, fetal pituitary tissue was implanted into the anterior hypothalamic area of the hypophysectomized rat by stereotactic methods. Electron-microscopic examination and hormonal blood levels demonstrated that ectopic pituitary tissue was able to survive to establish the correct anatomic relationship and thus perform secretory functions when transplanted intracerebrally.

Examination of autologous and embryonic cortical brain tissue transplantation to adult brain cortex in rats.

Autologous and embryonic cortical brain tissue was transplanted to adult rats in order to reconstruct experimentally degenerated cortical brain tissue. Rats were decapitated within 6 or 12 weeks. Viability of the graft tissues was studied by light and electron microscopy. Embryonic cortical brain tissue grafts became enlarged but adult cortical brain tissue grafts were found to be unaltered. Electron-microscopically observed mitochondria and other cell organellae and the newly vascularized areas clearly showed that the graft tissues were alive.