Biomedical subjects

Jeffrey Bennett

Publications and source records attributed to Jeffrey Bennett.

5 recordsLinked to original sources

PubMed2006

Identification of fibers at risk for degeneration by diffusion tractography in patients at high risk for MS after a clinically isolated syndrome.

PURPOSE: Focal inflammatory/demyelinating lesions are thought to be the source of Wallerian degeneration or other injury to local, transiting fiber tracts in the brain or spinal cord in multiple sclerosis (MS). A methodology is established to isolate connections between focal demyelinating lesions and intersecting fibers to permit explicit analyses of the pathology of secondary fiber injury distant from the focal lesion. MATERIALS AND METHODS: A strategy is described and feasibility demonstrated in three patients with a clinically isolated syndrome and positive MRI (at high risk for MS). The strategy utilizes streamtube diffusion tractography to identify neuronal fibers that intersect a focal lesion and pass through a region of interest, in this case the corpus callosum, where distal (to focal lesion) interrogation can be accomplished. RESULTS: A sizeable fraction of the normal appearing white matter (NAWM) in the early stages of disease can be defined in the corpus callosum, which is distinctive in that this tissue connects to distant demyelinating lesions. CONCLUSION: The new class of tissue called fibers-at-risk for degeneration (FAR) can be identified and interrogated by a variety of quantitative MRI methodologies to better understand neuronal degeneration in MS.

Adult↗

PubMed2006

Brainstem stereotactic biopsy sampling in children.

OBJECT: Although it is widely accepted that biopsy sampling is not indicated for the diagnosis and empiric treatment of diffuse pontine glioma, it is common to encounter patients with brainstem lesions that cannot be diagnosed on the basis of imaging studies alone. In cases not amenable to resection, a tissue diagnosis may still be necessary to make appropriate treatment recommendations. The authors retrospectively reviewed their institutional experience with stereotactic biopsy procedures in pediatric patients during a 4-year period. METHODS: A three-dimensional graphics workstation was used for trajectory planning to obtain biopsy samples of brainstem lesions in 10 patients. One patient experienced mild diplopia postoperatively. No other morbidity was noted; no patient died as a result of the procedure. The biopsy procedure yielded a pathological diagnosis in all cases. A later resection in one patient resulted in a change in diagnosis. Overall, the pathological findings were varied, and in some cases the tissue diagnosis altered the treatment recommendations. CONCLUSIONS: The findings in this small series suggest that brainstem stereotactic biopsy sampling in children is a safe procedure with a high diagnostic yield. In patients in whom radiographic findings are not consistent with diffuse pontine glioma and resection is not appropriate, stereotactic biopsy sampling should be considered.

Adolescent↗

PubMed2005

Effect of platelet-rich plasma with autogenous bone graft for maxillary sinus augmentation in a rabbit model.

PURPOSE: To evaluate the effect of platelet-rich plasma (PRP) on autogenous bone graft remodeling during sinus augmentation in a rabbit model. MATERIALS: Twelve New Zealand White rabbits were divided randomly into 3 groups based on their time of sacrifice (2, 4, and 8 weeks). All animals underwent a general anesthetic and harvesting of an autogenous bone graft from the right iliac crest with subsequent bilateral maxillary sinus augmentation. PRP was prepared via standard approved technique by acquiring 21 cc of autogenous blood and performing differential centrifugation to obtain PRP. One cc of PRP was produced that was mixed with bovine topical thrombin and calcium chloride. The left maxillary sinus received only autogenous bone, while the right maxillary sinus received a mixture of PRP mixed with autogenous bone, thus each animal acted as its own control. Equal volumes of bone were inserted in each maxillary sinus. Animals were sacrificed at 2, 4, and 8 weeks and all specimens were harvested for peripheral quantitative computed tomography (pQ-CT), static, and dynamic and histomorphometric analysis. RESULTS: Student t tests were performed comparing bone density via pQ-CT analysis, histomorphometric parameters of total bone area, and bone apposition rate. PRP had no statistically significant effect on bone graft healing in maxillary sinus augmentation when compared using standard pQ-CT, static, and dynamic histologic criteria. CONCLUSION: This study fails to find a direct stimulatory effect of PRP on healing of autogenous bone grafts using pQ-CT, static, and dynamic histomorphometric analyses.

Alveolar Ridge Augmentation↗

PubMed2003

Cavernous sinus fistulas: carotid cavernous fistulas and dural arteriovenous malformations.

Direct and indirect carotid cavernous sinus fistulas are uncommon vascular anomalies that result in increased pressure in the cavernous sinus. The subsequent changes in blood flow lead to orbital venous congestion, cranial neuropathies, and glaucoma. The following review summarizes knowledge of the clinical features, natural history, diagnostic testing, and therapy for carotid cavernous sinus fistulas.

Angioplasty↗

PubMed2003

Nutritional considerations in the surgical patient.

The nutritional status of the patient is integral to the care of the patient. Nutritional assessment and management begins with the initial patient contact and continues into the postoperative period.

Cytokines↗