Sheng-Long Howng

Differential expression of centrosomal proteins at different stages of human glioma

BackgroundHigh-grade gliomas have poor prognosis, requiring aggressive treatment. The aim of this study is to explore mitotic and centrosomal dysregulation in gliomas, which may provide novel targets for treatment.MethodsA case-control study was performed using 34 resected gliomas, which were separated into low- and high-grade groups. Normal human brain tissue was used as a control. Using immunohistochemical analysis, immunofluorescent microscopy, and RT-PCR, detection of centrins 1 and 2, γ-tubulin, hNinein, Aurora A, and Aurora B, expression was performed. Analysis of the GBM8401 glioma cell line was also undertaken to complement the in vivo studies.ResultsIn high-grade gliomas, the cells had greater than two very brightly staining centrioles within large, atypical nuclei, and moderate-to-strong Aurora A staining. Comparing with normal human brain tissue, most of the mRNAs expression in gliomas for centrosomal structural proteins, including centrin 3, γ-tubulin, and hNinein isoforms 1, 2, 5 and 6, Aurora A and Aurora B were elevated. The significant different expression was observed between high- and low-grade glioma in both γ-tubulin and Aurora A mRNA s. In the high-grade glioma group, 78.6% of the samples had higher than normal expression of γ-tubulin mRNA, which was significantly higher than in the low-grade glioma group (18.2%, p < 0.05).ConclusionsMarkers for mitotic dysregulation, such as supernumerary centrosomes and altered expression of centrosome-related mRNA and proteins were more frequently detected in higher grade gliomas. Therefore, these results are clinically useful for glioma staging as well as the development of novel treatments strategies.

17β-estradiol inhibits endothelin-1 production and attenuates cerebral vasospasm after experimental subarachnoid hemorrhage

Though cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) has been recognized for over half a century, it remains a major complication in patients with SAH. Clinical studies have shown that elevated levels of endothelin-1 (ET-1) are present in the cerebrospinal fluid of patients with SAH, suggesting that ET-1–mediated vasoconstriction contributes to vascular constriction after SAH. Administration of estrogen promotes vasodilation in humans and in experimental animals, in part by decreasing the production of ET-1. This study evaluated the influence of 17β-estradiol (E2) on the production of ET-1 and cerebrovasospasm in an experimental SAH 2-hemorrhage model in rat. A 30-mm Silastic tube filled with E2 in corn oil (0.3 mg/ml) was subcutaneously implanted in male rats just before SAH induction. The degree of vasospasm was determined by averaging the cross-sectional areas of basilar artery 7 days after first SAH. Plasma samples collected before death were assayed for ET-1. The protective effect of E2 in attenuating vasospasm achieved statistical significance when compared with the SAH only or SAH plus vehicle groups (P < 0.01). Concentrations of ET-1 were higher in the SAH only and SAH plus vehicle groups than in controls (P < 0.001). Serum levels of ET-1 in the SAH plus E2 and E2 only groups were significantly lower than those in the SAH only and SAH plus vehicle groups (P < 0.001). There was no significant difference between ET-1 levels in the healthy control and SAH plus E2 groups. A significant correlation was found between the cross-sectional areas of basilar artery and ET-1 levels (P < 0.001). The beneficial effect of E2 in attenuating SAH-induced vasospasm may be due in part to decreasing ET-1 production after SAH. The role of E2 in the treatment of cerebral vasospasm after SAH is promising and is worthy of further investigation.

A longitudinal study of central and peripheral nerve conduction in hypothyroid rats

In order to detect the dysfunction of central and peripheral nervous systems among rats with varied duration of hypothyroidism and to elucidate the pattern of recovery after thyroxine replacement, a series of BAEP and PNCS (Peripheral Nerve Conduction Study) were conducted and compared with age-matched controls. BAEP and PNCS were performed in three groups of hypothyroid animals 1, 3 and 5 months after thyroidectomy, respectively. Following initial electrophysiological assessment, thyroxine replacement was administered to each group of hypothyroid rats, and BAEP and PNCS were performed at two month intervals, up to two successive normal studies, or six months after the initiation of therapy, whichever came first. For BAEP, prolonged I-V interpeak latency was the most consistent abnormal finding in all groups of hypothyroid rats, and longer hypothyroid states correlated well with more severe central conduction disorder. Nevertheless, these abnormalities usually returned to normal after thyroxine replacement if the duration of hypothyroidism was less than 5 months. Regarding PNCS, all groups of thyroidectomized rats showed normal conduction before and after thyroxine therapy. The present study indicates that, in rats: (1) the peripheral nervous system seems to be more resistant to hypothyroidism than the central nervous system, or (2) the pathogenesis of central and peripheral nerve dysfunction in hypothyroid rats may occur through different mechanisms.

Type of Dementia in Taiwan ─ A Prospective Study

We prospectively investigated 100 consecutive inpatients with suspected dementia to evaluate the relative frequency of various types of dementia in a general hospital of Taiwan. Dementia was confirmed in 86 cases (86%) according to the dementia criteria of the third revised edition of the Diagnostic and Statistical Manual of Mental Disorders and Clinical Dementia Rating Scale (greater than or equal to 1). In contrast to the western developed countries, vascular dementia (VD) (35%) was the leading type of dementia, followed by Alzheimers disease (AD) (27%), mixed VD and AD (MIX) (14%), and other degenerative diseases (10%). Ten cases (11.6%) of potentially treatable dementia were identified and 8 of 10 had good improvement after appropriate treatment. There were significant age differences among patients with MIX, AD and VD (p less than 0.01). Those with MIX were the oldest (72.12 +/- 9.4) followed by AD (69.70 +/- 8.52) and VD (64.81 +/- 9.12). Males were slightly predominant in this series (male:female = 50:36). A comprehensive clinical investigation including laboratory tests, electroencephalography and CT are necessary in the assessment of demented patients in order to make correct etiological diagnoses which lead to appropriate treatment or management of this terrifying syndrome.

Prevention and reversal of vasospasm and ultrastructural changes in basilar artery by continuous infusion of CGS 35066 following subarachnoid hemorrhage.

Endothelin-1, a potent vasoconstrictive peptide, has been implicated in the pathogenesis of cerebral vasospasm following subarachnoid hemorrhage (SAH). The goal of this study was to evaluate the effect of continuous intravenous infusion of a highly selective endothelin-converting enzyme-1 inhibitor, CGS 35066, on the prevention and reversal of cerebral vasospasm following SAH. New Zealand white rabbits were subjected to SAH by injecting autologous arterial blood into the cisterna magna. Infusion of CGS 35066 at dosages of 1, 3, or 10 mg/kg/ day was initiated either 1 hr and 24 hrs later in the prevention and reversal protocols, respectively. Animals were sacrificed by perfusion-fixation 48 hrs after SAH induction. The cross-sectional areas of basilar arteries were measured using computer-assisted videomicroscopy. Ultrastructural changes in basilar arteries were determined using electron microscopy. CGS 35066 significantly prevented and reversed the arterial narrowing after SAH in all three groups. The mean cross-sectional areas of arteries from animals in both the prevention and reversal protocol groups that received 10 mg/kg/day of CGS 35066 did not differ significantly from those of the healthy controls. Histological studies of the basilar artery in the 10 mg/kg/day treatment group did not show pathomorphological changes, such as corrugation of the endothelium seen at 2 days after SAH induction or vacuole formation in the endothelial cells noted in the vehicle-treated SAH group. These findings suggest that CGS 35066 is a promising therapeutic agent for the prevention and reversal of cerebral vasospasm after SAH. It also prevents the pathological changes in vascular walls due to SAH.

Neuroprotective effect of CGS 26303, an endothelin-converting enzyme inhibitor, on transient middle cerebral artery occlusion in rats

Endothelin-1 has been shown to aggravate the ischemicreperfusion injury in the neocortex of rats. The purpose of this study was to examine the effect of an endothelin-converting enzyme inhibitor, CGS 26303, on neurological deficit, infarct size, and extent of edema after transient occlusion of the middle cerebral artery and bilateral common carotid arteries (triple vessel occlusion) in rats. In the pretreatment study, male Sprague-Dawley rats underwent a 90-minute triple vessel occlusion, and CGS 26303 was administered intravenously 30 minutes before triple vessel occlusion. The compound was subsequently administered at 6, 12 and 18 hours post-triple vessel occlusion, and neurological status was evaluated 1, 12 and 24 hours after triple vessel occlusion. Animals were sacrificed at 24 hours post-triple vessel occlusion, brains were perfusion-fixed, and infarct areas and brain swelling were determined. Total infarct areas were reduced when compared with vehicle-treated animals by 48%, 50%, and 57% in rats receiving CGS 26303 at 1, 3, and 10 mg/kg, respectively, while the neurological score was significantly improved in the highest-dose CGS 26303-treated group. In another study, CGS 26303 treatment was initiated 1 hour after triple vessel occlusion. Total infarct areas were reduced by an average of 42-50% in the CGS 26303 treatment group. Neurological scores of animals treated with CGS 26303 at 10 mg/kg were decreased by 59% and 45% upon evaluation at 12 and 24 hours post-triple vessel occlusion, respectively. These results demonstrate that CGS 26303 may have potential for the treatment of focal ischemic stroke.

Analysis of Surgically Treated Intraspinal Tumors in Southern Taiwan

The medical records of 117 patients with spinal tumors who underwent surgery with pathologic confirmation from January 1999 to April 2004 at Kaohsiung Medical University Hospital were reviewed. Data from this review were compared with those obtained from the same institution 10 years earlier (covering the period 1988‐1995) and from other reported series. There were 69 male and 48 female patients aged from 13 to 87 years old (mean age, 51.9). The most common pathologic findings were metastasis in 45.3% (53/117), nerve sheath tumors in 28.2% (33/117), menin‐giomas in 12% (14/117) and neuroepithelial tumors in 6% (7/117). The peak ages at diagnosis were 41‐50 years and 61–70 years. A slight male predominance was noted for all tumors, except meningiomas. Motor weakness, even paralysis, was the major clinical presentation (64–86%), followed by sensory deficits (50%) and pain (42%). The location of tumors was most often in the thoracic (50.4%; 59/117), lumbosacral (27.4%; 32/117) and cervical spine (22.2%; 26/117) segments. Among the metastatic tumors, the lung (22.6%) and breast (15.1%) were the most common primary sites of origin, followed by unknown origin, the liver (hepatocellular carcinoma), the gastrointestinal tract and the nasopharynx (nasopharyngeal cancer).

Unilateral Stereotactic Posteroventral Globus Pallidus Internus Pallidotomy for Parkinson's Disease: Surgical Techniques and 2-Year Follow-Up

With the advent of levodopa (L‐dopa) and the recognition of its striking effect on Parkinsons disease (PD), virtually all surgical procedures for PD ceased from the mid 1960s. However, there has been a resurgence of pallidotomy and other stereotactic procedures in the last two decades as physicians realized that most PD patients eventually face medical failure after long‐term treatment with L‐dopa. Nine PD patients, three men and six women, with an average age of 62 years and disease duration of 13 years underwent unilateral globus pallidus internus (GPi) pallidotomy contralateral to the side with marked akinetic symptoms and drug‐induced dyskinesia. All patients were evaluated using the Unified Parkinsons disease Rating Scale (UPDRS) after drug withdrawal and while taking their optimal medical regimen, preoperatively and 6, 12, and 24 months after surgery. There was significant improvement in activities of daily living and motor subscores as well as total UPDRS score in the “off” state at the 2‐year follow‐up, which mainly resulted from improvement in contralateral bradykinesia and rigidity. Significant improvements in contralateral akinetic symptoms and drug‐induced dyskinesia were also observed in the “on” state and were sustained for at least 2 years. Ipsilateral and axial symptoms were not altered by unilateral GPi pallidotomy. The complications of surgery were generally well tolerated. One patient had a small postoperative asymptomatic hemorrhage identified by routine follow‐up magnetic resonance imaging. Another two patients developed temporary sexual disinhibition and auditory hallucination, respectively, which resolved spontaneously 2 weeks after surgery. The effect of pallidotomy for alleviation of akinetic parkinsonism is modest but significant, and continues to be effective for at least 2 years. Further analytical studies, especially the correlation of clinical effects and lesion locations, are important not only to provide direct feedback for surgeons to examine the technical accuracy and but also to facilitate understanding of the pathophysiology of PD.

A study of central and peripheral nerve conduction in patients with primary hypothyroidism: the effects of thyroxine replacement.

Somato-Sensory Evoked Potential (SSEP) and Peripheral Nerve Conduction (PNC) studies were performed in twenty patients with primary hypothyroidism to elucidate the changes of central and peripheral nervous systems in hypothyroid state and the effects of thyroxine replacement. Before thyroxine replacement therapy, eleven patients had significantly delayed SSEP (prolonged latencies of N9, N13, or N20), and only three patients had prolonged central conduction time (between N13 and N20). PNC abnormalities with decreased conduction velocity and diminished amplitudes were found in fourteen patients. After thyroxine treatment, both SSEP and PNC studies demonstrated significant improvement and paralleled the clinical neurological amelioration. The central and peripheral conduction velocities returned to normal limits, while the abnormality in amplitude still persisted. There were also discrepancies between SSEP and PNC studies in both the abnormality pattern and the recovery potential. Our observations may suggest: firstly, both the SSEP and PNC studies may be useful, alternative tools in monitoring the neurological disorders in hypothyroidism; and secondly, the pathogenesis of central and peripheral nervous dysfunction in hypothyroidism may be via different mechanisms.

549. Peripheral Gene Delivery of Glial Cell Line-Derived Neurotrophic Factor Alleviated Neurological Deficits in Diabetic Rats

The neurological deficit in peripheral nerves is one of the major complications associated with diabetes. Deprivation of trophic factors may contribute to the pathogenesis of diabetic neuropathy while restored expression of neurotrophic factors could ameliorate such sensory abnormalities. Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor that effectively prevents neuronal death and restores the synapse conduction during trauma of central nervous system. In the present study, we evaluated the therapeutic potential of GDNF gene delivery for neuropathy in diabetic rats. After injection of streptozotocin for 14 days, a reduction in nerve conduction velocity (NCV) with a concomitant increment in H-reflex was detected in diabetic rats by electrophysiological studies. Single, intramuscular (IM) injection of adenovirus encoding GDNF (Ad-GDNF) led to systemic GDNF expression for at least 35 days. Besides, the declined GDNF level in sciatic nerve was also restored by GDNF gene delivery. After gene delivery for 2-4 weeks, Ad-GDNF-treated rats exhibited a significant increment in NCV (P<0.05) and a concomitant decrease in H-reflex latency (P<0.05) comparing with animals of control groups. IM GDNF gene delivery was well tolerant to diabetic rats without affecting their biochemical parameters Therefore, peripheral GDNF gene delivery may hold potential for treatment of diabetic neuropathy.