How olfaction disorders can cause depression? The role of habenular degeneration.

The removal of bilateral olfactory bulbs (OBs) can result in serious behavioral, neurochemical, neuroendocrine, and neuroimmune alterations in depressed patients. However, there is little information on how olfactory bulbectomy (OBX) leads to depression. Habenular nuclei and their connections are important in the regulation of psychomotor and psychosocial behaviors through afferent impulses of the olfactory system. Therefore, we investigated whether OB lesions lead to habenular degeneration. We used a sample of 50 rats (25 female and 25 male) for this study. Of these rats, five male and five female rats were taken as the control group. The remaining 40 rats (20 male and 20 female rats) constituted the study group, and frontal burr holes were performed at the OB level on these rats. OB cauterization was applied to 10 male and 10 female rats (n=10, 10; study group 1), mechanical OBX was applied to five male and five female rats (n=5, 5; study group 2), and no procedure was performed on the remaining 10 rats (n=5, 5). The psychomotor movements; pregnancy rates; and sexual, feeding, maternal, social, and grooming behaviors for both study groups were observed daily for 3 months. Their OBs, olfactory cortices, and habenular complexes were examined using stereological methods. All of the animals in the study groups, especially in the cauterization group, demonstrated anorexia, nutritional disorders, weight loss, psychomotor retardation, sexual aversion, decreased grooming behavior, and reduced social interaction similar to depression symptoms. As compared to the control group, the pregnancy rates, number of offspring per mother rat, and birth weights in the study groups were lower, whereas the number of stillbirths was higher. Gross anatomical examinations revealed that the OBs of all of the animals in the study groups were atrophied. Histopathological examinations detected prominent neuronal loss due to apoptosis in the habenular structures in the study groups. We detected a relationship between a decreased healthy neuronal density of the habenula and depressive symptomatology in rats with OBX. We suggest that olfaction disorders might cause neuropsychiatric disorders by affecting neuronal degeneration in habenular nuclei.

Intracerebral sewing needle.

A 9-year-old male patient complaining of seizure attack was admitted to the neurosurgery department. Radiologic investigations revealed a 5-cm-long metallic sewing needle extending from the right frontal cortex to the right lateral ventricle. Burr hole surgery was performed and the needle was grasped with biopsy forceps and removed with endoscopic guidance. The patient recovered without any complications.

Thrombogenetic effect of facet denervation using in disc surgery on spinal radicular arteries: an experimental study.

BACKGROUND: Although it is well known that electric current can be hazardous for living tissues, facet denervation (FD) has been largely used in spine surgery. In spite of the fact that vascular structures are protected during the operation, some neurovascular disorders may develop after surgery. In this study, we investigated if FD can cause lesions of the radicular arteries. METHODS: Seventeen rabbits were included in this study. Three of them were used as control group and the remainder were subjected to L4-5 discectomy. FD was applied via monopolar electrocauterization to only half of the operated animals. One month after the surgery, all animals were sacrificed and the L4-5 spinal radicular arteries examined histopathologically. RESULTS: Vascular wall injury, endothelial necrosis, muscular lesions and thrombus development were seen in the majority of the spinal radicular arteries of the animals subjected to FD. CONCLUSION: Facet denervation via monopolar electrocautery may cause arterial lesions and thrombus development in the radicular arteries and therefore it should not be applied unless obligatory.

The role of neuron numbers of the petrosal ganglion in the determination of blood pressure: an experimental study.

BACKGROUND: Baroreceptor reflexes are regulated by nerve terminals of the glossopharyngeal and vagal nerves. The body of pressure-sensitive neurons of these nerves is located in the petrosal ganglion of both nerves. We examined whether there is a relationship between the neuron numbers of the inferior ganglion of the glossopharyngeal nerve and blood pressure values. METHODS: Petrosal ganglions were examined in 18 male hybrid rabbits divided into three equal groups: Group A normotensive (TA=90-100 mmHg), Group B hypertensive (TA>100 mmHg); and Group C hypotensive (TA<90 mmHg). After examination of blood pressure for one week, all animals were sacrificed, and the petrosal ganglions extracted bilaterally and examined histopathologically using the physical dissector method. RESULTS: The mean (+/-SD) neuronal density was: Group A 8700+/-200, Group B 7800+/-250 and Group C 9800+/-300, respectively. The difference between the groups B and C as compared to A was significant (p<0.01) while the difference between Groups B and C was highly significant (p<0.001). CONCLUSIONS: An inverse relationship was noticed between the neuronal density in the petrosal ganglion and blood pressure values with potential implications in the study of the etiology of hypertension.

Histopathological alterations in ciliary ganglions in meningitis: an experimental study.

BACKGROUND: Although it is well known that meningitis frequently results in optic nerve (ON) and oculomotor nerve (OMN) dysfunctions, the effects of meningitis on the ciliary ganglion (CG) have not been studied. It is expected that the CG may be affected due to the involvement of these cranial nerves in meningitis. In this study, we aimed to investigate the effect of meningitis on the CG. METHODS: This study was conducted on thirteen rabbits. Experimental meningitis has been achieved with Streptococcus pneumonias inoculation into the cisterna magna of the animals. After follow-up of two months, all animals were sacrificed. CGs of all animals were examined histopathologically. Neuron numbers and morphological changes of the CGs were examined. RESULTS: Arachnoiditis and axonal degeneration at the cisternal segments of both oculomotor and optic nerves were observed. Neuronal irregularity, cellular angulation, shrinkage, nuclear irregularity and cytoplasmic condensation were observed in neurons of the CG. The mean number of live neurons in a CG was 3200 in healthy rabbits, whereas it was 2800 in animals with meningitis. CONCLUSION: Cisternal segments of the ON and OMN have a meningeal sleeve and a rich vascular supply. Meningitis may cause vasculitis or vasospasm at these arteries and may result in infectious neuropathy of the OMN and ON, and also afferent and efferent loops of the light reflex were structurally interrupted. Consequently, parasympathetic preganglionic denervation of the CG may occur and may result in degeneration in the neurons of the CG.

Protective effects of cisternal irrigation on leptomeningeal and cortical structures in meningitis: an experimental study.

BACKGROUND: Meningitis, termed as foreign material collection in the subarachnoid space, leads to various meningeal, cerebral and spinal cord pathologies. Meningitis still remains a problematic disease with severe complications in spite of advanced medical technology. AIMS: In this study, we aimed to investigate the role of cisternal irrigation in the prevention of meningitis complications. SETTING AND STUDY DESIGN: Experimental study was done in the Social Security Hospital of Erzurum. Histopathological specimens were evaluated in the Pathology Department in the Ataturk University Research Hospital, Erzurum, Turkey. MATERIALS AND METHODS: This study was conducted on twelve lambs. Experimental meningitis was achieved with streptococcus pneumonia. Two animals were not treated. Ten animals were given Cefotaxime (4 x 1g/day) for 20 days, and additionally half of these animals underwent cisternal irrigation. Then, all animals were sacrificed and brains were observed histopathologically. RESULTS: Massive purulent CSF formation, hemorrhagic cortical lesions, vascular congestion, leptomeningeal and cortical adhesions and brain edema were observed in the non-irrigated group, but these findings were observed slightly or absent in the irrigated group. CONCLUSION: Meningitis can affect all central neural tissues, consequently serious central nervous system lesions may develop. The irrigation procedure may decrease the percentage and severity of meningitis complications by way of the excretion of inflamed purulent collection from the subarachnoid spaces.

Cerebral fat embolism: pulmonary contusion is a more important etiology than long bone fractures.

Lipid embolism is a serious and life-threatening problem and usually arises as a complication of severe trauma associated with long bone or pelvic fractures. It is generally thought that fat droplets enter the circulation at the site of fracture. In the systemic circulation, they become emboli to brain, kidney and other areas. Lipids are absorbed from the intestinal tract and transported into pulmonary tissue via thoracic duct and exposed to first catabolic procedures in the lungs. We have predicted that systemic lipid embolism may not occur unless bone fractures lead to pulmonary injury. This study was planned to investigate this hypothesis with respect to the role of pulmonary contusion and long bone fractures in the formation of cerebral fat embolism. Twenty male hybrid rabbits were included in this study. Pulmonary contusion was performed on half of the rabbits (n = 10) and femur fracture was applied to the remaining ones (n = 10). Ten days after procedure, all rabbits were sacrificed. Brain specimens were taken by frozen-section method and stained with Sudan black. Intraarteriolar lipid particles in the brain were examined microscopically. Cerebral fat embolism was detected in seven animals exposed to pulmonary contusion and only in one animal exposed to femur fracture. The mean number of branches of middle cerebral artery at midparietal level occluded with fat particles were higher in the pulmonary contusion group than in the long bone fracture group. In conclusion, we found that pulmonary contusion had more deleterious effects than long bone fracture in the formation of cerebral fat embolism.

Chronic treatment of haloperidol causes vasoconstriction on basilar arteries of rats, dose dependently.

Haloperidol is a widely used antipsychotic drug, which exerts its effects via antagonizing the dopaminergic D2 receptors. Also it affects a number of receptors on vascular bed and other tissues. The impact of haloperidol on vascular bed seems still debatable and not clear. In the present study, haloperidol was given to adult rats in 0.5, 1, 2.5 and 5 mg kg(-1) doses, once a day, intraperitoneally in 1 ml volumes, for 9 weeks. After decapitation under Pentothal anesthesia, brains and basilar arteries were dissected out at midpontine level immediately. Conventional histopathology and morphometric analysis were carried out on the dissected artery branches. Medial and adventitial layers, endothelial cells and internal elastic membranes were observed as normal in the control group. It was determined clearly that the lumen of basilar artery in the control group was larger than in the other groups and also it was observed that is more regular the lumen contours of basilar artery in control group compared with other groups. Finally, wall thickness of basilar artery in all experimental groups decreased significantly due to the vasoconstriction. Regarding the total, lumen and wall volumes, 1 mg kg(-1) haloperidol induces vasoconstriction more than the other groups.

Histopathologic changes in oculomotor nerve and ciliary ganglion in aneurysmatic compression injuries of oculomotor nerve.

BACKGROUND: Bilateral common carotid artery ligation (BCCAL) increases vertebrobasilar blood flow and leads to increased luminal pressure, luminal enlargement, wall thinning, convolutions and sometimes aneurysm formation in posterior circulation arteries, especially the posterior communicating arteries (PcomA). PcomA aneurysms compress the oculomotor nerves. The principal aim of this investigation is to examine the histopathologic results of the compressive effect of PcomA aneurysms on the oculomotor nerves (OMN) and on ciliary ganglions (CG). METHODS: When we observed the effects of BCCAL on the posterior circulation arteries of the brain in fifteen ligated rabbits after sacrifice, we noticed aneurysm formation on these arteries in three rabbits. These aneurysms developed on the PcomAs compressed the oculomotor nerves. These compressed nerves and normal oculomotor nerves together with their ciliary ganglions were examined histopathologically. RESULTS: A PComA aneurysm developed in three rabbits from 15 ligated animals and these aneurysms compressed the oculomotor nerves on the same side. Partial peripheral necrosis and axonal loss were seen on the compressed oculomotor nerves. Concomitantly, cellular loss and necrosis were also observed on their ganglions. CONCLUSION: Bilateral common carotid artery ligation may lead to PcomAs and these aneurysms could compress the oculomotor nerves. Compression injuries of oculomotor nerve may cause cellular injury and necrosis on both oculomotor nerves and ciliary ganglions.

The use of reservoir shunt in chronic subdural hematoma.

Recurrent chronic subdural hematomas (CSDH) can be a therapeutic challenge. We report the use of reservoir shunts for continuous irrigation and drainage of the subdural space for a prolonged period. This system appears to be more useful than an external drainage system.

Neurodegenerative effects of monopolar electrocauterization on spinal ganglia in lumbar disc surgery.

BACKGROUND: Monopolar electrocauterization (MEC) is widely used in spine surgery however electrical currents are hazardous for neural tissues, such as the spinal ganglia sited in the intervertebral foramina. We aimed to investigate the effects of MEC on spinal ganglia. METHOD: Fifteen male hybrid rabbits were included in the study. Three of the animals were used to analyze the findings regarding spinal ganglia without operation. The remaining animals underwent L4-5 disc surgery. For intra-operative facet denervation MEC was used for half of the animals. After one month, all animals were sacrificed and L5 spinal ganglia were removed for histopathological examination. The number and morphological changes of neurons in spinal ganglia were examined. FINDINGS: The mean number of live neurons was 22610 in non-operated rabbits; 21617 in the non-MEC group and 16692 in the MEC group. Neuronal degeneration was more prominent in the MEC group than in the non-MEC group. CONCLUSIONS: MEC used during spine surgery may be injurious to spinal ganglia and should be used with caution.

A neuro-Behcet's lesion in oculomotor nerve nucleus.

OBJECTIVE: Fascicular oculomotor nerve involvement is occasionally seen in Behcet's disease, but nuclear involvement is very rare. CASE PRESENTATION: A 25-year-old woman presented with the Behcet's symptoms and the left eye problems. Physical examination revealed muco-cutaneous lesions, eyelid ptosis, mydriasis, upward and medial gaze palsy and lateral deviation on the left eye. Serologic tests were positive. An inflammatory lesion was detected in the left oculomotor nerve nucleus on magnetic resonance imaging. Neuro-Behcet's disease was considered the most likely diagnosis. RESULT: Dexamethasone treatment was ordered. Muco-cutaneal lesions, laboratory abnormalities were normalized after 1 year; but oculomotor nerve palsy persisted in spite of improvement in radiological findings. CONCLUSION: Clinical signs of oculomotor nerve palsy may persist despite the radiological improvement.

Neuro-Behçet's disease involving the pons with initial onset of affective symptoms.

We report a case with Behçet's disease with initial onset of affective symptoms. This disease most commonly affects the brain stem in the nervous system, but a large lesion is very rare in the pons; initial onset of affective symptoms has not yet been reported in literature. This case was treated successfully with corticosteroids. Total clinical improvement was observed and the lesion was reduced in size within nine months (1.5 x 1.3 cm to 0.2 x 0.4 cm).

Reliability of cord formation in BACTEC 12B/13A media for presumptive identification of Mycobacterium tuberculosis complex in laboratories with a high prevalence of Mycobacterium tuberculosis.

A total of 1208 positive BACTEC vials were examined for the presence or absence of serpentine cording. A very high (92.9%) rate of laboratory prevalence was obtained for Mycobacterium tuberculosis complex. The sensitivity, specificity, positive and negative predictive values of this test were 92.7%, 95.3%, 99.6% and 50.0%, respectively. It was concluded that testing cord formation in laboratories that have a high prevalence of Mycobacterium tuberculosis complex is an exceptionally reliable method for preliminary reporting of cording-positive cases; however, for cording-negative cases, preliminary reports based solely on cord formation are not reliable. It was also observed that the length of the incubation period has a significant effect on cord formation. Incubation periods of 4 days or less are not sufficient to determine noncording in smears prepared from positive BACTEC vials.

Protective effect of posterior cerebral circulation on carotid body ischemia.

BACKGROUND AND PURPOSE: Carotid Bodies (CB) are fed mainly by External Carotid Artery (ECA) and rarely by Internal Carotid Artery (ICA). We aimed to investigate the effect of Bilateral Common Carotid Artery ligation and BCCAL plus bilateral external carotid artery ligation on CB. METHODS: This study has been conducted on 30 hybrid male rabbits. Normal CB analyses were made in six of these animals and others divided into two groups. BCCAL has been applied to the 1st group, and the 2nd group has undergone bilateral ECA ligation in addition to BCCAL. After sacrificing the animals, both sides CB were histopathologically observed. Normal and ischemic cells were counted. FINDINGS: Bilateral Common Carotid Artery ligation did not cause total atrophy in CB. Partial reversible atrophy of CB was seen in group I, but that atrophy was found to be irreversible and all animals died within one week after ligation in group II. INTERPRETATION: Retrograde blood flow mechanisms and collateral circulation impede the oligemic CB atrophy after BCCAL. But bilateral ECA ligation, in addition to BCCAL, causes both sides irreversible CB atrophy and death of animals within one week of ligation. ABSTRACT: The CB are parasympathetic paraganglia. They are chemoreceptors and located at the bifurcation zone of common carotid arteries. They are fed mainly by ECA or by its branches and rarely by ICA. As a consequence of this, BCCAL and/or ligation of external branches of common carotid artery may lead to an ischemic impairment of CB. In order to analyse the effect of carotid stenosis on CB, CB were directly examined in 6 of 30 hybrid rabbits. BCCAL was applied to twelve rabbits (group I) with ligation of both ECA in addition to BCCAL were made to the others (group II). Animals were followed up four months in group I; but all of the animals in group II died within one week. From both sides the CB were taken including the carotid bifurcation and histopathological changes were evaluated. As a result, it has been observed that incomplete ischemic lesions have developed in the CB because of retrograde blood flow from posterior circulation to the ECA providing blood for the CB. But in the second group these changes were irreversible and on both sides CB complete atrophy developed in those whose ECA were also ligated bilaterally.

Atretic cephalocele communicating with lateral ventricles.

Atretic cephaloceles are thought to be involuted true meningoceles or encephaloceles. They are located at the midline of the parietal or occipital region and usually joined to the subarachnoidal space. We present a 6-month-old girl with atretic cephalocele communicating with the lateral ventricles.