PubMed Health⌕ Search

Biomedical subjects

S L Webb

Publications and source records attributed to S L Webb.

8 recordsLinked to original sources
PubMed1999

Correlation of magnetic resonance imaging parameters with clinical disability in multiple sclerosis: a preliminary study.

Magnetic resonance imaging (MRI) is frequently used to monitor new treatments in multiple sclerosis (MS), but its role is limited by the uncertain relationship between MRI parameters and clinical disability. A brain MRI study using nine MRI parameters was undertaken in 15 MS patients with a wide spectrum of disability to evaluate the relationship between each parameter and disability. A strong correlation was found between disability (measured using Kurtzke's EDSS) and total lesion load on both proton density (PD; r = 0.79) and T1 (r = 0.71) weighted sequences. There was also a strong correlation of disability with average lesion magnetisation transfer ratio (MTR; r = -0.74) and calculated T1 (r = 0.71) but not with calculated T2 or the average signal intensity of lesions on the conventional T1-weighted, PD-weighted and heavily T2-weighted images. Thus, four parameters which measured either the extent of lesions (PD lesion load) or their pathological severity (MTR, calculated T1, hypointense T1-lesion load) were correlated significantly with disability. While this suggests that such parameters will be useful in treatment trial monitoring, further multi-parameter MRI studies, of larger cohorts and using a wider range of techniques, are indicated.

Adult↗
PubMed1996

Apparent diffusion coefficients in benign and secondary progressive multiple sclerosis by nuclear magnetic resonance.

The diffusion characteristics of water in brain white matter were studied in patients with benign and secondary progressive multiple sclerosis (MS), and also in normal controls. In the MS patients, both lesions and normal-appearing white matter (NAWM) were examined to assess whether pathological differences might be evident from the diffusion behavior. A volume-selective technique was used to reduce data acquisition time and improve the reliability and precision of the measurements. This also allowed the time-dependence of apparent diffusion coefficients to be assessed. While lesions from both patient groups showed an elevated diffusion coefficient, no differences between the two groups were found. In addition, NAWM was elevated for both patient groups compared with the control group, although this was only statistically significant for patients with a benign disease course. The degree of elevation of the diffusion coefficient within the individual lesions measured was not related to the disability of the patient. Pathological differences between lesions in patients with different disease courses, if they exist, have not been detected in this study of brain water diffusion.

Brain↗
PubMed1996

Nitric oxide synthesis inhibition attenuates behavioral actions of neuropeptide FF.

Neuropeptide FF (NPFF) has certain antiopiate actions and may play a role in opiate tolerance and dependence. Third ventricle injection of 10 micrograms NPFF induces a quasimorphine abstinence syndrome in opiate-naive rats. Nitric oxide synthesis may also contribute to opiate tolerance and dependence. The present study tests the hypothesis that NPFF acts through stimulation of nitric oxide synthase (NOS). Third ventricular injection of 10 micrograms NPFF precipitated an average of 46 abstinence-like signs during a 20-min observation. Pretreatment (30 min earlier) with 7.5 or 15 mg/kg s.c. of the NOS inhibitor nitro-L-arginine (L-NNA) resulted in a significant and dose-dependent alleviation of NPFF-induced abstinence-like signs. The anti-NPFF activity of 15 mg/kg L-NNA was blocked by 750 mg/kg L-arginine, but not by the same amount of D-arginine, indicating that L-NNA attenuates NPFF activity through a stereospecific inhibition of NOS.

Animals↗
PubMed1996

Spinal cord atrophy and disability in multiple sclerosis. A new reproducible and sensitive MRI method with potential to monitor disease progression.

Recent MRI studies in multiple sclerosis have highlighted the potential importance of spinal cord atrophy (implicating axonal loss) in the development of disability. However, the techniques applied in these initial studies have poor reproducibility which limits their application in the serial monitoring of patients. The aim of this study was to develop a highly reproducible and accurate method for the quantification of atrophy. The technique we describe demonstrates an intra-observer coefficient of variation (scan-rescan) of only 0.8%. When applied to 60 patients with clinically definite multiple sclerosis there was a strong correlation between spinal cord area and disability measured by Kurtzke's Expanded Disability Status Scale (EDSS) (r = -0.7, P < 0.001). The correlation was graded providing evidence for a causal connection. At levels 3 and 8 of the EDSS we observed a reduction in average cord area of 12 and 35%, respectively. Given its reproducibility, the magnitude of the change detected and the strong correlation with disability, this new technique should prove to be a sensitive measure of progressive neurological deterioration and could be readily incorporated into imaging protocols aimed at monitoring therapy.

Adult↗
PubMed1990

Neonatal serum protein levels as indicators of nutritional status: normal values and correlation with anthropometric data.

Twenty-one infants were studied to compare cord serum protein concentrations (SPCs) with samples drawn 3 days after birth. The results were compared with anthropometric measurements of the infants to determine the usefulness of serum studies in predicting the nutritional status of the newborn. SPCs of 19 serum protein subfractions were measured by laser nephelometry. In 17 of 19 proteins, the cord blood and newborn blood levels were highly correlated. C1Q and haptoglobin were the exceptions. The SPC was converted to serum protein mass (SPM) as follows: SPM = [(SPC) x (birth weight) x (0.85) x (1-hematocrit)]. Blood volume is approximately 0.85 dl of blood/kg of body weight and since these proteins are largely intravascular, it was postulated that the estimated total protein mass would be a more accurate index of nutritional state. Six proteins (C3, C4, prealbumin, retinol binding protein, transferrin, and albumin) were highly correlated with the anthropometry (arm circumference, skin fold thickness, length, weight, etc.). This study indicates that umbilical cord blood may be used to estimate a newborn's nutritional status. Transport proteins such as albumin, transferrin, retinol binding protein, and prealbumin are commonly used to assess adult nutritional status, and may be used in infants after estimating the total mass of the protein in the serum.

Anthropometry↗
PubMedDate not supplied

A reproducible repositioning method for serial magnetic resonance imaging studies of the brain in treatment trials for multiple sclerosis.

Serial MRI is an important measure of disease progression in evaluating the treatment of multiple sclerosis (MS). Accurate comparisons of scans for lesion activity and lesion volume require precise repositioning of patients. A simple, reproducible repositioning method is described. In a multicenter treatment trial of MS using beta-interferon-1b, this method has been successful, with only 1.1% of scans being rejected because of poor repositioning.

Adjuvants, Immunologic↗