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Cheng-Loong Liang

Publications and source records attributed to Cheng-Loong Liang.

14 recordsLinked to original sources

Injury severity and cell death mechanisms: effects of concomitant hypovolemic hypotension on spinal cord ischemia-reperfusion in rats.

A number of previous studies indicated that ischemia-reperfusion injury causes two distinct types of cell death--necrosis and apoptosis--in the central nervous system. It was also implicated that the intensity of injury can somehow affect the cell death mechanisms. By occluding the descending thoracic aorta with or without simultaneously induced hypovolemic hypotension in rats, we established a model of experimental spinal cord ischemia-reperfusion (I/R) in which the injury severity can be controlled. Recordings of carotid blood pressure (CBP) and spinal cord blood flow (SCBF) showed that aortic occlusion induced dramatic CBP elevation but SCBF drop in both the normotensive (NT) and hypotensive (HT) groups of rats. However, the HT group demonstrated significantly lower SCBF during aortic occlusion, and much slower elevation of SCBF after reperfusion, and extremely poor neurological performance. Spinal cord lesions were characterized by infarction associated with extensive necrotic cell death, but little apoptosis and caspase-3 activity. In contrast, in the NT group, I/R injury resulted in minor tissue destruction associated with persistent abundant apoptosis, augmented caspase-3 activity, and favorable functional outcome. The relative sparing of motoneurons in the ventral horns from apoptosis might have accounted for the minor functional impairment in the NT group. The severity of I/R injury was found to have substantial impact on the histopathological changes and cell death mechanisms, which correlate with neurological performance. Our results implicate that injury severity and duration after injury are two critical factors to be considered in therapeutic intervention.

Animals↗

Outer table craniotomy for frontal sinus mucocele.

Variants of the external osteoplastic flap procedure or endoscopy have been used to approach the frontal sinus mucocele. The authors introduce a modified external approach for radical resection of the mucocele. Using the bicoronal skin incision, the skin flap exposed the right upper orbital rim. The outer table craniotomy was then performed to expose the frontal sinus cavity while carefully preserving the inner table, with radical removal of the mucocele mucosa. The sinus cavity was irrigated with hyper-oxide solution to ensure adequate destruction of possible residual mucosa. The fascia of the frontalis muscle was split, with one part placed into the mucocele cavity to plug the nasofrontal duct. The advantages of the procedures for mucocele removal include clear visualization of the frontal sinus for radical resection of the mucosa, preservation of the inner table avoiding dura manipulation, prevention of central nervous system infection, possibly lower rates of recurrence, prevention of mucosal ingrowth by plugging of the nasofrontal ducts with fascia, and favorable cosmetic outcome. The disadvantages are more intensive surgery comparable to the endoscopic approaches and execution difficulties when the frontal mucocele is small. Additional clinical studies are needed to evaluate the efficiency and safety of this procedure.

Craniotomy↗

Shunt surgery for hydrocephalus complicating cryptococcal meningitis in human immunodeficiency virus-negative patients.

From 1988 through 2001, 27 patients with cryptococcal meningitis who had hydrocephalus were identified and were treated by placement of ventriculoperitoneal (VP) shunts. To assess the predictive value of the response to VP shunts in terms of outcome in these patients, univariate analysis for variables was performed. Poor outcome was associated with a Glasgow Coma Scale score of 48 h (P=.02). Use of VP shunts did not result in a good response or outcome in comatose patients. Thus, any delay in the diagnosis or treatment of patients with hydrocephalus could cause a deterioration of consciousness and is associated with poor outcome.

Antifungal Agents↗

Intracranial suppuration: a clinical comparison of subdural empyemas and epidural abscesses.

BACKGROUND: We compared the clinical features and therapeutic outcomes of intracranial suppurations (IEs) caused by sub-dural empyema (SDEs) and epidural abscesses (EAs). METHODS: Twenty-four patients with IE were retrospectively identified at our institution over a period of 14 years. Therapeutic outcomes at 6 months were determined using the Glasgow Outcome Scale. RESULTS: Among them, 15 had SDE and nine had EA with or without SDE. The three most frequently encountered clinical features Included fever (79%), disturbed consciousness(58%), and seizures (54%). Postneurosurgical or posttraumatic states (42%) and complication after meningitis (38%) were the two most common modes of infection. The overall mortality rate was 8% (2/24). However, if mortality and severe neurologic sequelae were included in the poor outcome group, then 29% (7/24) of our patients would be considered treatment failures. CONCLUSION: In this study, SDE commonly arose following bacterial meningitis with a more fulminant course, but no deaths occurred. In contrast, EA commonly has a more Indolent course and is postoperatively or post-traumatically related, and therefore may have a higher mortality rate based on primary brain pathophysiology alone. Inpatients with meningitis or who undergo postneurosurgical procedures and develop fever, progressive disturbed consciousness, seizures, and focal neurologic signs, immediate neuroimaging studies should be per-formed to determine whether IE is present. Early surgical drainage and aggressive antimicrobial therapy are necessary.

Adolescent↗

Neuroprotective synergy of N-methyl-D-aspartate receptor antagonist (MK801) and protein synthesis inhibitor (cycloheximide) on spinal cord ischemia-reperfusion injury in rats.

Thoraco-abdominal aortic surgery requiring temporal cross clamping of the aorta results in a high incidence of paraplegia due to temporary ischemia of the spinal cord. Both excitotoxicity and apoptosis are implicated in the pathogenesis of spinal cord ischemia-reperfusion injury. We propose that the N-methyl-D-aspartate receptor antagonist dizocilpine maleate (MK801) and the protein synthesis inhibitor cycloheximide produce a synergic effect in a rodent model of spinal cord ischemia-reperfusion injury. Injury was induced by 20 min of temporal thoracic aorta occlusion and distal blood volume reduction. After injury, the animals were treated with vehicle, MK801, cycloheximide or MK801 and cycloheximide. Hind limb motor function recovery was better in the MK801 and combined therapy groups than in the control and cycloheximide groups. The mean neuronal survival rate of the control group was 45.3 +/- 3.2% on the 7(th) day after injury. In the MK801 and cycloheximide treatment groups, neuronal survival increased to 62.4 +/- 3.6% and 54.1 +/- 2.4%, respectively. For the combined therapy group, neuronal survival increased to 75.6 +/- 2.5%. The number of apoptotic cells in the control group was 211.4 +/- 8.8 per section on the 7th day after ischemic insult, while apoptosis was significantly reduced in the cycloheximide (96.8 +/- 6.7 cells) and combined (84.8 +/- 8.5 cells) groups. It was unchanged in the MK801 group (209.8 +/- 5.4 cells). These results suggest that combined treatments directed at blocking both N-methyl-D-aspartate receptor-mediated excitotoxic necrosis and caspase-mediated apoptosis might have synergic therapeutic potential in reducing spinal cord ischemia-reperfusion injury.

Animals↗

Rapidly growing internal carotid artery aneurysm after amphetamine abuse: case report.

Amphetamine is one of the most common illicitly abused drugs in certain countries. It is a potent sympathomimetic that may lead to vascular events, including stroke and myocardial infarction. Most reports of stroke after amphetamine abuse are of intracerebral hemorrhage. In this report, the authors describe a ruptured aneurysm of the right internal carotid artery in a young man with amphetamine abuse. It grew rapidly within 2 weeks. Surgery revealed fibrosis and fibrinoid necrosis around the aneurysm. The aneurysm was successfully embolized with Guglielmi detachable coil. A rapidly growing aneurysm in the major intracranial vessels resulting from amphetamine abuse is very rare.

Adult↗

Nuclear factor-kappaB-regulated cyclooxygenase-2 expression in surgery-associated paraspinal muscle injury in rats.

OBJECT: Paraspinal muscle injury is a common but neglected complication of posterior spinal surgery. Evidence suggests that surgical retraction places mechanical and oxidative stress on the paraspinal muscles and that inflammation is a major postoperative pathological finding in the muscles. The roles of cyclooxygenase (COX)-2 and nuclear factor (NF)-kappaB in the inflammatory processes after retraction remain to be clarified. METHODS: In the control group, paraspinal muscles were dissected from the spine via a posterior incision and then laterally retracted. Paraspinal muscle specimens were harvested before as well as at designated time points during and after persistent retraction. The time course of NF-kappaB activation was determined by gel shift assay. Expression of COX-2 was examined using Western blot analysis and immunohistochemistry. The severity of inflammation was evaluated based on histopathology and myeloperoxidase (MPO) activity. The NF-kappaB activation was inhibited by the administration of pyrrolidine dithiolcarbamate (PDTC) in the PDTC-treated group. Retraction induced early activation of NF-kappaB in paraspinal muscle cells. The expression of COX-2 could not be detected until 1 day postoperativley, reaching a peak at 3 days. The time course of COX-2 expression correlated with that of inflammatory responses and MPO activity. Pretreatment with PDTC inhibited intraoperative NF-kappaB activation and greatly downregulated postoperative COX-2 expression and inflammation in the muscles. Postinflammation fibrosis was also abolished by PDTC administration. CONCLUSIONS: Both NF-kappaB-regulated COX-2 expression and inflammation play an important role in the pathogenesis of surgery-associated paraspinal muscle injury. The therapeutic strategy of NF-kappaB inhibition may be applicable to the prevention of such injury.

Animals↗

Use of ventriculoperitoneal shunts to treat uncontrollable intracranial hypertension in patients who have cryptococcal meningitis without hydrocephalus.

Between 1997 and 2000, 4 human immunodeficiency virus-negative patients in our institution had cryptococcal meningitis with uncontrollable intracranial hypertension. All 4 patients were treated with antifungal drugs as well as ventriculoperitoneal (VP) shunts for intracranial hypertension. Neurological deficits that were unresponsive to pharmacologic treatment were resolved by use of the VP shunt. Uncontrollable elevation of intracranial pressure associated with cryptococcal meningitis can be resolved by use of a VP shunt, even when imaging studies do not reveal hydrocephalus.

Adult↗

Implication of telomere length as a proliferation-associated marker in schwannomas.

BACKGROUND AND OBJECTIVES: Some schwannomas in the central nervous system may demonstrate relatively aggressive behavior in pathological findings and clinical course. We evaluate the diagnostic values of telomerase activity and telomere length in the clinicopathological behavior of schwannomas. METHODS: Thirty surgical specimens from intracranial and intraspinal schwannomas were analyzed by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) for telomerase activity and terminal restriction fragments (TRFs) using Southern blot for telomere length. Proliferative indices were also studied. RESULTS: Telomerase activity could not be detected in all schwannomas. Elongated telomere length (mean 17,101 +/- 259 bp) was found in four specimens (13.3%). Three of these four were found to have mitotic figures, high vascularity, cellularity, and pleomorphism in the pathological findings. The proliferative indices (35) showed correlative high values. One patient died of this disease, and one was found to have recurrence at follow-up evaluation. Those that displayed benign histopathological pictures showed relatively short telomere length (8,866 +/- 271 base pairs) and low proliferative indices (21). These is a significant difference between these two groups (P = 0.001). CONCLUSIONS: Elongation of telomere length in schwannomas appears to predict aggressive clinicopathological behavior.

Adolescent↗

Quadriplegia in a patient who underwent posterior fossa surgery in the prone position. Case report.

Quadriplegia is a well-known complication of posterior fossa surgery performed while the patient is in the sitting position but is rarely associated with the prone position. A case of an 18-year-old man with a cerebellar medulloblastoma is described. There was no evidence of previous cervical disease. The patient suffered quadriplegia after undergoing surgery in the prone position. Postoperative magnetic resonance imaging demonstrated a long hyperintense C2-T1 lesion on T2-weighted sequences. The authors speculate that, during the prolonged period in which the neck was in hyperflexion, overstretching of the cervical spinal cord and compromise of its blood supply might have caused this devastating complication.

Adolescent↗

Oxidative stress and heat shock protein response in human paraspinal muscles during retraction.

OBJECT: The need for wide dissection and forceful retraction of paraspinal muscles often required for posterolateral lumbar fusion and fixation may severely jeopardize the muscles, structurally and functionally. The underlying pathophysiology of muscle damage may involve both mechanical and ischemic mechanisms. On the other hand, the surgery-related stress may trigger certain protective responses within the insulted paraspinal muscles. This study was conducted to assess the relationship between the oxidative stress and the stress response mediated by heat shock protein 70 (HSP70) induction within paraspinal muscles being retracted. METHODS: Multifidus muscle specimens were surgically obtained before, during, and after retraction in patients with lumbar spondylolisthesis undergoing posterolateral lumbar fusion, pedicle fixation, and laminectomy. Muscle samples were analyzed to determine HSP70 and malondialdehyde (MDA) levels. Both HSP70 expression and MDA production within multifidus muscle cells were increased significantly by retraction. Expression of HSP70 then decreased after a peak at 1.5 hours of retraction, whereas MDA levels remained elevated even after release of retractors for reperfusion of the muscles. Analysis of histopathological and immunohistochemical evidence indicated that the decline of HSP70 synthesis within muscle cells after prolonged retraction was the result of severe muscle damage. CONCLUSIONS: Results of this study highlight the deleterious effect of intraoperative retraction on human paraspinal muscles at the cellular and molecular levels. The authors also found that intraoperative maneuvers aimed at reducing the oxidative stress within the paraspinal muscles may help to attenuate surgery-related paraspinal muscle damage.

Aged↗

Percutaneous vertebroplasty improves pain and physical functioning in elderly osteoporotic vertebral compression fracture patients.

BACKGROUND: Osteoporotic vertebral compression fractures are being recognized increasingly often in the elderly. They frequently cause severe and prolonged back pain and physical decline. Bed rest, narcotic analgesia, and external bracing were the only therapeutic modalities available in the past and had limited success. OBJECTIVE: The purpose of our study was to determine the efficacy of percutaneous vertebroplasty in treating osteoporotic vertebral compression fractures in the elderly. METHODS: Twenty-two vertebroplasties were performed in 16 elderly patients. Pain relief, medication requirements, and physical functioning were evaluated before and 24 h and 6 months after vertebroplasty. RESULTS: There was 81% improvement in pain intensity 24 h after operation, and 94% improvement was noted at the 6-month follow-up checkup. Physical functioning improved 69% 24 h after vertebroplasty and 63% 6 months later. Medication requirements also decreased in 75% of the patients. CONCLUSION: Percutaneous vertebroplasty for osteoporotic vertebral compression fractures is safe and effective and should not be withheld from the elderly.

Administration, Cutaneous↗