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Biomedical subjects

R W Griebel

Publications and source records attributed to R W Griebel.

11 recordsLinked to original sources
PubMed2006

A Fourier transform infrared microspectroscopic imaging investigation into an animal model exhibiting glioblastoma multiforme.

Glioblastoma multiforme (GBM) is a highly malignant human brain tumour for which no cure is available at present. Numerous clinical studies as well as animal experiments are under way with the goal being to understand tumour biology and develop potential therapeutic approaches. C6 cell glioma in the adult rat is a frequently used and well accepted animal model for the malignant human glial tumour. By combining standard analytical methods such as histology and immunohistochemistry with Fourier Transform Infrared (FTIR) microspectroscopic imaging and multivariate statistical approaches, we are developing a novel approach to tumour diagnosis which allows us to obtain information about the structure and composition of tumour tissues that could not be obtained easily with either method alone. We have used a "Stingray" FTIR imaging spectrometer to analyse and compare the compositions of coronal brain tissue sections of a tumour-bearing animal and those from a healthy animal. We have found that the tumour tissue has a characteristic chemical signature, which distinguishes it from tumour-free brain tissue. The physical-chemical differences, determined by image and spectral comparison are consistent with changes in total protein absorbance, phosphodiester absorbance and physical dispersive artefacts. The results indicate that FTIR imaging analysis could become a valuable analytic method in brain tumour research and possibly in the diagnosis of human brain tumours.

Animals↗
PubMed2003

Quercetin promotes functional recovery following acute spinal cord injury.

We tested the hypothesis that quercetin, a potent Fe(2+)-chelating flavonoid, would decrease secondary damage following spinal cord trauma. MRI studies using the relaxation of the T1 proton signal caused by Fe(2+) ions and the dose-dependent reversal of this effect by addition of quercetin in aqueous solution were used to guide us to the dosage of quercetin to be used in animal experimentations. Forty-four male Wistar rats were used in two experimental series to test the hypothesis that administration of quercetin improves recovery of motor function after acute traumatic spinal cord injury. Animals were subjected to laminectomy and subjected to an extradural 40-g force clip compression for 5 sec at T7. Quercetin or saline was administered intraperitoneally 1 h after injury and then every 12 hr thereafter. Recovery of motor function was assessed using BBB scores at weekly intervals for 4 weeks. A dose of 2.5 micromoles quercetin/kg body weight did not result in significantly better functional outcome, whereas doses ranging from 5 to 100 micromoles quercetin/kg body weight resulted in a significantly better functional outcome with half or more of the animals walking, although with deficit; in contrast, no animals walked in the group of saline-treated animals. No significant differences in behavioral outcome were seen amongst the doses ranging from 5 to 100 micromol/kg, nor was there a difference if animals were treated for 4 or 10 days. Therapeutic outcome was coincident with more efficient iron clearance, suggesting that one possible mechanism whereby quercetin decreases secondary damage is through iron chelation.

Acute Disease↗
PubMed2001

Spinal angiolipoma.

BACKGROUND: Spinal epidural angiolipoma is a rare cause of spinal cord compression. We present a case and review the clinical presentation, radiological appearance, pathological aspects and treatment of this distinct clinico-pathological entity. METHODS: A case of a 46-year-old woman with a five-month history of progressive myelopathy affecting her lower extremities is presented. CT and MRI revealed a large epidural fat-containing mass compressing the spinal cord dorsally at the T7-T8 level. A laminectomy was performed with gross total resection of the lesion. RESULTS: The patient's neurologic symptoms improved postoperatively. A two-year follow-up period has revealed no signs of tumor recurrence and no neurological deficit. CONCLUSION: The diagnosis of spinal angiolipoma should be considered in the differential diagnosis of spinal cord compression. Magnetic resonance imaging is the investigation of choice. The surgical objective is complete excision but, for anterior lesions involving bone, an overly aggressive approach should be tempered by an awareness of the overall indolent natural history of so-called "infiltrating" spinal angiolipomas that are only partially excised.

Adolescent↗
PubMed2001

Promoting glutathione synthesis after spinal cord trauma decreases secondary damage and promotes retention of function.

The study aimed to 1) quantify oxidative stress in spinal cord after crush injury at T6, 2) determine whether the administration of the procysteine compound L-2-oxothiazolidine-4-carboxylate (OTC) would up-regulate glutathione (GSH) synthesis and decrease oxidative stress, and 3) determine whether decreased oxidative stress results in better tissue and function retention. We demonstrate that spinal cord compression (5 s with a 50 g aneurysm clip) at T6 in rats results in oxidative stress that is extensive (significant increases in oxidative stress seen at C3 and L4) and rapid in onset. Indices of oxidative stress used were GSH content, protein carbonyl content, and inactivation of glutathione reductase. Administration of OTC resulted in a marked decrease in oxidative stress associated with a sparing of white matter at T6 (16+/-1.9% retained in OTC-treated animals vs. less than 1% in saline-treated). Behavioral indices in control, saline-treated, and OTC-treated animals after 6 wk were respectively: angle board scores (59 degrees, 32 degrees, and 42 degrees ), modified Tarlov score (7, 2.4, and 4.1), and Basso-Beattie-Bresnahan score (21, 5.3, and 12.9). We conclude that administration of OTC after spinal cord trauma greatly decreases oxidative stress and allows tissue preservation, thereby enabling otherwise paraplegic animals to locomote.

Animals↗
PubMed1992

Malignant rhabdoid tumor of the central nervous system with subarachnoid dissemination.

A case of primary central nervous system malignant rhabdoid tumor is presented. Clinical, radiological, and histopathological findings are described in detail. Because of a relatively long clinical course after presentation, it was possible to assess the clinical and radiological response to different treatment modalities: surgery, chemotherapy, and radiotherapy. Despite the complete clinical and radiological response that was achieved after subtotal excision, two cycles of chemotherapy, and high-dose radiotherapy, the tumor recurred within 4 months of completion of the treatment, with wide subarachnoid dissemination. Radiotherapy treatment of whole cranial axis is recommended.

Brain Neoplasms↗
PubMed1989

The importance of "accessory" outflow pathways in hydrocephalus after experimental subarachnoid hemorrhage.

This study evaluated the changes in pathways of cerebrospinal fluid (CSF) outflow that accompanied acute and compensated hydrocephalus in the rabbit. Intraventricularly injected 99mTc antimony sulfide was used as a tracer of outflow pathways, and specified structures were counted 12 to 24 hours after injection. Fifteen rabbits were divided into three groups: 1) an acutely hydrocephalic group in which 3 cisternal injections of blood were followed by a study of CSF pressure, ventricular size, and CSF outflow pathways 1 week after the last injection; 2) a control group treated according to the same protocol, except that sterile saline was injected instead of blood; and 3) a chronic group also treated according to the same protocol but in which the animals were maintained an average of 4 weeks after the last blood injection. Ventricular size was measured by computed digitation and expressed as an area ratio of ventricle to brain (VBR). In control animals, 11.8% of the injected colloid dosage was found in cranial perineural lymphatic channels, and 4.8% appeared in the spinal cord. The mean CSF pressure was 149 +/- 20.2 mm H20 (mean +/- SE) and the mean VBR was 0.040 +/- 0.003. In animals evaluated 1 week after subarachnoid injection, accessory cranial perineural lymphatic outflow decreased significantly to 3.4%, and spinal cord activity increased to 9.8% (P less than 0.05, two-tailed t-test). These animals were hydrocephalic and had CSF pressure of 247 +/- 25.1 mm H20 (mean +/- SE) and VBR of 0.083 +/- 0.009.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Calcium deposits on CSF shunts. Clinical observations and ultrastructural analysis.

CSF shunts removed from seven patients 5-12 years after placement were studied. Examination in each case revealed gritty mineral deposits adherent to the external surface. The deposits were further analyzed by routine histology, spectroscopy and scanning electron microscopy. These results and the clinical consequences of this calcification are discussed. Microdefects in the tubing may contribute to delayed calcification of Silastic shunt tubing.

Calcinosis↗
PubMed1987

The surgical treatment of childhood moyamoya disease.

Moyamoya disease is a progressive disorder, predominantly seen in childhood, that can cause severe permanent disability. The search for effective treatment has largely been unsuccessful in the past, but recent efforts at surgical intervention have shown promising results. The natural history of moyamoya disease, the options for treatment, and a series of patients from the Hospital for Sick Children in Toronto are reviewed. The results of surgical treatment are encouraging and the authors believe that it should be offered to all pediatric patients in the progressive stage of the disease.

Adolescent↗
PubMed1986

Congenital spinal cord tumors in children.

The paediatric spinal cord may host a wide variety of congenital tumors, the most common of which have been discussed. Although the majority of these lesions are benign their delayed diagnosis, serious infectious complications or associated congenital anomalies may expose the patient to life threatening morbidity or serious permanent disabilities. Prompt surgical management provides a cure in most instances, and the gratification of a neurologically intact child.

Child↗