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S Pierce

Publications and source records attributed to S Pierce.

113 records · Page 7Linked to original sources
PubMedDate not supplied

Dynamic contrast-enhanced T2*-weighted MR imaging of tumefactive demyelinating lesions.

PURPOSE: Dynamic contrast-enhanced T2*-weighted MR imaging has been helpful in characterizing intracranial mass lesions by providing information on vascularity. Tumefactive demyelinating lesions (TDLs) can mimic intracranial neoplasms on conventional MR images, can be difficult to diagnose, and often result in surgical biopsy for suspected tumor. The purpose of this study was to determine whether dynamic contrast-enhanced T2*-weighted MR imaging can be used to distinguish between TDLs and intracranial neoplasms that share common features on conventional MR images. METHODS: We retrospectively reviewed the conventional and dynamic contrast-enhanced T2*-weighted MR images and medical records of 10 patients with tumefactive demyelinating disease that was diagnosed by either biopsy or strong clinical suspicion supported by laboratory evaluation that included CSF analysis and evoked potential tests. Twelve TDLs in 10 patients and 11 brain tumors that appeared similar on conventional MR images were studied. Relative cerebral blood volume (rCBV) was calculated from dynamic MR data and was expressed as a ratio to contralateral normal white matter. rCBV values from 11 patients with intracranial neoplasms with very similar conventional MR imaging features were used for comparison. RESULTS: The rCBV values of TDLs ranged from 0.22 to 1.79 (n = 12), with a mean of 0.88 +/- 0.46 (SD). The rCBV values of intracranial neoplasms ranged from 1.55 to 19.20 (n = 11), with a mean of 6.47 +/- 6.52. The difference in rCBV values between the two groups was statistically significant (P =.009). The difference in rCBV values between TDLs and primary cerebral lymphomas (n = 4) was less pronounced but was statistically significant (P =.005). CONCLUSION: Dynamic contrast-enhanced T2*-weighted MR imaging is a useful diagnostic tool in differentiating TDLs from intracranial neoplasms and may therefore obviate unnecessary surgical biopsy.

Adolescent↗
PubMedDate not supplied

Protective effects of a monoclonal antibody against lipid A in endotoxic shock.

Bacterial lipopolysaccharide given intravenously at 30 mg/kg to anesthetized rats results in rapid systemic hypotension and hypovolemia, elaboration of cytokines, increased proteolysis and vascular endothelial dysfunction. When a monoclonal antibody SdJ5-1.17.15 (SdJ5) directed against the lipid A moiety of lipopolysaccharide was administered at (1.25 or 5.0 mg/kg) 5 min prior to the endotoxin, significant protection was afforded to rats. This protection was manifested by a significant reduction in the early hypotension, as well as attenuation of hypovolemia and proteolysis. To evaluate endothelial function, superior mesenteric artery rings were isolated from endotoxemic rats 4 h after endotoxic challenge. Lipopolysaccharide (LPS) significantly reduced superior mesenteric artery vasorelaxation to acetylcholine and A23187, two endothelium-dependent vasodilators, but not to NaNO2, an endothelium-independent vasodilator. SdJ5 significantly preserved vasorelaxation responses to both acetylcholine and A23187, indicating a marked degree of endothelial preservation by this anti-lipid A monoclonal antibody. The protection was dose-dependent since 0.3 mg/kg of SdJ5 did not provide significant protection in any variable measured. Moreover, there was no significant difference between the 1.25 mg/kg and 5.0 mg/kg dose of SdJ5. Furthermore, plasma concentrations of TNF-alpha, a cytokine involved in mediating many of the effects associated with endotoxemia, was significantly reduced in SdJ5-treated animals. Thus, SdJ5 appears to be capable of counteracting many of the in vivo sequelae of endotoxemia in rats.

Acetylcholine↗