Christos Tsonidis

An immunohistochemical study of mechanoreceptors in lumbar spine intervertebral discs.

There are limited data concerning mechanoreceptors in normal human lumbar intervertebral discs. The aim of our study was to determine the types of mechanoreceptors in the two lower intervertebral discs in normal adult cadaveric donors and to review the literature. Twenty-five lumbar (L4-5 and L5-S1) intervertebral discs were retrieved from 15 fresh cadavers. We utilized immunoreactivity against the S-100 protein to localize specialized nerve endings. Immunoreactivity showed receptors in 92% of discs. The most frequent type had morphology resembling the Ruffini type receptor (88%), followed by the Golgi type. Free nerve fibers were frequently present. All neural structures were found in the superficial layers of the annulus fibrosus, in longitudinal ligaments, or between these two. The anterior part of the L5-S1 disc had a greater frequency of encapsulated receptors than the other parts (p=0.022), which may be correlated with the high shear forces to which the lumbosacral junction is subjected.

Successful, combined long-term treatment of cerebral aspergillosis in a liver transplant patient.

Invasive aspergillosis has long been recognized as one of the most significant and often fatal opportunistic fungal infections in liver transplant recipients. We report a case of a liver transplant recipient who developed an Aspergillus fumigatus brain abscess that produced significant neurologic symptoms. The patient was managed successfully with a combination of surgery and medical treatment with Voriconazole. To our knowledge, this is the second such case reported in the literature.

The effect of porcine orexin A on glucose dependent insulinotropic polypeptide plasma concentrations in pigs

The orexigenic system was discovered in 1998. It consists of two neuropeptides, Orexin A and Orexin B. Researchers have focused more on Orexin A, since its intracerebroventricular injection into the lateral ventricle of the rats brain causes an increase in the consumption of food. Besides, it seems that, apart from appetite, Orexin A regulates many other physiological functions with unknown regulatory and metabolic mechanisms. Orexin A is produced by a small group of neurons located in and around the lateral hypothalamic area. It has been known for decades that the latter is involved in regulating feeding in mammals. An intravenous injection of Orexin A causes changes in insulin and glucagon plasma concentrations in rats. In this study, we investigated the possible effects of the central administration of porcine Orexin A on glucose-dependent insulinotropic polypeptide plasma concentrations in pigs, and examined whether these changes are related to the possible effect of the neuropeptide on the enteroinsular axis.

Dermal Sinus Tract of the Thoracic Spine Presenting with Intramedullary Abscess and Cranial Nerve Deficits.

Congenital dermal sinus tract of the spine is an unusual developmental defect which represents a failure of the surface ectoderm and dermal elements to separate from the neuroectoderm. A 15-month-old female presented with high fever, severe right hemiparesis, difficulty breathing and cranial nerve deficits. Magnetic resonance imaging (MRI) of the spine revealed a congenital dermal sinus tract at the Th6 level, an intramedullary collection extending up to the brainstem and a probable intramedullary cystic lesion. The child was operated acutely with ligation of the sinus tract, drainage of the abscess and partial removal of the intramedullary lesion. Due to abscess recurrence, she was reoperated with complete excision of the dermal sinus tract, abscess redrainage and subtotal excision of the dermoid cyst (retaining a part of its capsule). Pus culture isolated Corynebacterium species and Peptococcus species and histology of the lesion showed a dermoid cyst. Postoperatively, after an initial neurologic deterioration, she progressively improved. An MRI scan at 15 months neither showed recurrence of the collection nor regrowth of the lesion. Spinal dermal sinus tracts that remain unnoticed or untreated can result in serious complications and should be operated as soon as possible to prevent undesirable sequelae.

Dermatomal SEPs — a complementary study in evaluating patients with lumbosacral disc prolapse

We investigated the value of Dermatomal Somatosensory Evoked Potentials in 24 patients with unilateral radiculopathy due to lumbosacral disk prolapse. All patients had clinical signs and symptoms of disk prolapse and positive findings on neuroradiologic testing. We assessed the latency and the amplitude of the first positive waveform of Dermatomal SEPs, as well as conducting peripheral nerve conduction studies and electromyography. Our studies showed a clear correlation of Dermatomal SEP abnormalities and radiculopathy in up to 83.3% of subjects studied. Use of electromyography testing provided this correlation in about 62.5% of the same subjects. On the basis of these results, we propose that Dermatomal SEPs have value in complementing the routine electrophysiological testing of the patients with radiculopathy and provide a sensitive non-invasive technique for defining the level of disk prolapse.

The effect of porcine Orexin A on a C-peptide plasma concentrations in pigs

The hypothalamus and the neuropeptides that are produced and act within its neuronal circuits constitute an area of extensive laboratory research. In 1998, the neuropeptide, Orexin A, was discovered and isolated from the hypothalamus of the rat. An i.c.v. injection of Orexin A into the lateral ventricle of the rats brain causes an increase in the consumption of food, and, apart from appetite, it also seems to be regulating many other normal functions of the organism, whose regulatory and metabolic mechanisms remain unknown to date. The neuropeptide is produced by a small cluster located in and round the lateral hypothalamic area. It has been known for decades that this area is involved in the regulation of feeding and energy homeostasis in mammals. The intravenous, subcutaneous, or i.c.v. injection of Orexin A causes changes in insulin and glucagon concentrations. The same effect is also seen under in vitro experimental conditions. In this study, we investigated the potential effects of i.c.v. administration of porcine Orexin A on c-peptide concentrations in the peripheral blood of pigs, and tested whether these changes are associated with the potential effect of the neuropeptide on the function of the pancreas.

Comparison of dermatomal SEPs and operative findings in lumbar disc disease

This report deals with an estimation of the diagnostic value of dermatomal somatosensory evoked potentials (SEPs), by correlating the neurophysiological data to clinical, neuroradiological and operative findings in lumbar disc protrusion. Our material consists of 12, surgically treated patients with lumbar disc protrusion in which diagnostic work up included history, neurological examination, routine lumbar spine films, computerised tomography and MRI of the lumbar spine, in addition to neurophysiological investigation, especially conduction velocity studies, and SEPs recorded by the standard methods, as well as after dermatomal stimulation. The retrospective analysis disclosed a correlation for the SEPs after dermatomal stimulation and surgical findings, in 83% of our cases.

A 57-YEAR-OLD FEMALE WITH A CEREBELLAR MASS

A 57-year-old female presented with recurrent episodes of nausea and vomit, as well as instability during walking. The patient had a history of uterine leiomyosarcoma, for which she underwent a hysterectomy and oophorectomy 8 months ago. CT scan revealed a calcified mass that was located in the left cerebellar hemisphere which was resected. Histologically, multiple tissue fragments displayed infiltration of cerebellar tissue by polymorphic spindle-shaped cells. The Ki-67 proliferation index was approximately 20%. The morphological and immunohistochemical data, in association with the past clinical history, were consistent with cerebellar metastasis of uterine leiomyosarcoma. Although adjuvant radiotherapy was introduced, the patient died of cardiopulmonary arrest 6 weeks after the surgical procedure. The present case adds to the body of literature being the second report of uterine leiomyosarcoma metastatic to the cerebellum.

Intraoperative facet joint injury during anterior cervical discectomy and fusion: an experimental study.

OBJECT Disorders of the cervical spine can be successfully addressed by surgical intervention when the choice of such intervention takes into account the possible complications in the treated and adjacent structures. The aim of this study was to investigate the potential for intraoperative trauma in cervical zygapophysial joints and to describe possible pathological changes that may occur during cervical spine surgery. METHODS Fifteen sheep underwent surgical intervention via an anterior cervical approach; discectomy at the C5-6 level was performed. In 10 animals, the discectomy was accompanied by titanium cage fusion. The sheep were killed immediately after completion of the operation. Radiological examination of the isolated cervical spines followed. Furthermore, the cervical spines were submitted to decalcification and incised using a microtome, and tissue sections were then studied using light microscopy. RESULTS Radiological examination was used to assess vertebral alignment, vertebral body (VB) morphology, implant position, and endplate and facet joint gross morphology. Histological examination of the endplate and VB demonstrated degenerative lesions as well as cellular necrosis. The study of the facet joints at the treated as well as at adjacent segments (both above and below) revealed in some cases edema between the collagen fibers of the joint capsules, congestion, and microhemorrhages. Injuries were evident in animals in which the Caspar device was used. CONCLUSIONS Histopathologically confirmed lesions occurred in facet joints while anterior cervical spine surgery was being performed in sheep. The findings were indicative of trauma and, in the case of human spine surgery, could possibly account for several postoperative complications and patient complaints.