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Biomedical subjects

L Manning

Publications and source records attributed to L Manning.

27 records · Page 2Linked to original sources
PubMed1991

Hemispheric activation vs spatio-motor cueing in visual neglect: a case study.

We report a case of mild visuo-spatial neglect consequent upon right-hemisphere stroke. At the time of testing, the patient had a complete left visual field deficit but only a very slight left hemiparesis. Under conventional testing conditions, line bisection performed with the right hand showed more severe left neglect than when performed with the left hand. This pattern of performance could, however, be modified, both quantitatively and qualitatively, by changing the starting position of the patient's hand when bisecting horizontal lines. The results suggest that spatio-motor cueing has a more profound effect upon task performance than does differential hemispheric activation per se. We also provide a demonstration that, in a normal subject, the starting position of the hand is likewise a crucial determinant of task performance. In this case, however, there is also an interaction between the hand (and hence hemisphere) deployed and the position of that hand in space.

Adult↗
PubMed1990

Pharmacokinetics and protein binding of methocarbamol in renal insufficiency and normals.

We determined plasma methocarbamol concentrations over 24 h following a 1.5 g methocarbamol dose (off-dialysis day) to 8 chronic haemodialysis patients and compared these results to those from 17 healthy male volunteers. The harmonic mean elimination half-life was similar between the two groups, 1.24 and 1.14 h, respectively. tmax and the weight-adjusted Cmax were 1.1 h and 27.0 mg.m-1 for haemodialysis patients and 1.1 and 23.1 mg.l-1 for normals. Relative systemic availability was assessed by comparing weight-normalized AUC x k10 products. These results indicate no significant differences with respect to methocarbamol absorption, with the relative systemic availability in patients being 113%. These data suggest that absorption and elimination of methocarbamol is similar between normal subjects and patients undergoing maintenance haemodialysis.

Chromatography, High Pressure Liquid↗
PubMed1990

Individual variation in line bisection: a study of normal subjects with application to the interpretation of visual neglect.

Investigations of left visuo-spatial neglect are reviewed with special reference to line bisection performance. Attention is then drawn to inconsistencies in the direction and magnitude of transection displacements in group studies of normal controls. We argue that the lack of reliable information about normal mechanisms for line bisection makes it impossible to interpret pathological performance in neglect. Accordingly, we report a case-series of 22 normal young adults, each of whom bisects 10 lines of differing lengths 10 times each. There is very substantial between-subject variation in both the magnitude and direction of the linear regression of transection displacement on line length; there are likewise considerable differences in the magnitude of the linear regression of standard deviation on line length. These two sources of individual variation are uncorrelated. We propose a psychophysical theory of line bisection, and suggest that the basic mechanisms responsible for task-performance are qualitatively intact in visuo-spatial neglect, albeit quantitatively impaired.

Adult↗
PubMed1990

Individual variation in line bisection: a study of four patients with right hemisphere damage and normal controls.

In a previous study of line bisection, [Manning et al., Neuropsychologia 28, 647-655, 1990] we have shown that normal young adults show significant linear regressions of both transection displacement (TD) and standard deviation (SD) on line length. Furthermore, there was considerable individual variation in the magnitude of SDs and the direction and magnitude of TDs. These two sources of variance were uncorrelated. In the current study we provide a constructive replication of these findings on an older population that constitutes a more appropriate control sample for patients with stroke. The performance of four patients with right hemisphere stroke is then interpreted in terms of the constraints observed in normal subjects. All the patients showed qualitatively intact line bisection, but with quantitative impairments of varied severity. When analysed in two pairs, the patients also showed a double-dissociation between the magnitude of their mean transection displacements and the SDs of those means. This result is in conformity with the prediction based upon a lack of correlation between these two measures in normal subjects.

Aged↗
PubMed1989

Sustained release of 5-fluorouracil from ethylene acetate copolymer.

Pharmacologic inhibition of fibroblast proliferation and scar formation remains an important consideration in many ophthalmologic surgical procedures. Such inhibition is particularly important in glaucoma filtration surgery. A sustained release system for 5-fluorouracil (5-FU) using ethylene vinyl acetate copolymer (Elvax) was characterized in vitro. 5-FU was incorporated into Elvax discs of 4 mm diameter. Discs were coated to allow sustained and predictable release over a 14 day period. Alteration of coatings, which act as rate-controlling membranes, allowed variation in the pattern of 5-FU release from the core which acts as the drug reservoir. This system for the sustained release of 5-FU may prove valuable in glaucoma surgery where the suppression of cellular proliferation is desired. The non-inflammatory nature of Elvax suggests this compound may provide an alternative means of 5-FU delivery.

Delayed-Action Preparations↗
PubMed1989

Can parents do a throat culture?

Throat swabs for Group A beta-hemolytic Streptococcus were obtained from 98 patients, ages 4 to 17 years, both by their parents and by physician investigators. Compared with results obtained by physicians, there was a false negative rate of 32% (P less than 0.001) for the parents. The discrepancy was greater in the youngest age group (38% false negative rate in the 4- to 8-year-olds) compared with older children (P less than 0.001). The overall sensitivity and negative predictive value for the parent-obtained swabs were 68 and 45%, respectively. In the 4- to 8-year-old group, these values were 62 and 37%, respectively. Because there were no false positives the positive predictive value was 100%. We conclude that the false negative rate for untrained parents obtaining throat swabs is too high to warrant the implementation of home testing for Group A streptococci.

Adolescent↗
PubMed1986

Interhemispheric asymmetry in facial expression recognition: relationship to field-dependence.

Sixty college students, 30 males and 30 females, with a well defined cognitive style (measured by means of three tests), carried out a recognition task of six unambiguous facial expressions which were unilaterally presented in a tachistoscopic condition. A significant left visual field superiority was present for the field independenct subjects; a low but significant right visual field superiority was present for the field dependent subjects. No differences were found between the sexes.

Adolescent↗
PubMed1982

Exclusive binding of immunoglobulin to Fc gamma receptors on macrophages in 3-methylcholanthrene-induced murine tumors.

Immunogenic, chemically induced, murine tumors generally are infiltrated with large numbers of Fc gamma receptor (Fc gamma R)-positive cells, most of which are mononuclear phagocytes. This study demonstrates in inbred C3H/HeN mice that such immunogenic tumors contain large amounts of cell-bound immunoglobulin (Ig) and that, within the sensitivity limits of indirect immunofluorescence, the tumor-associated Ig is bound exclusively to host-derived Fc gamma R-positive cells. Depletion of Fc gamma R-positive cells from tumor cell suspensions removed all Ig-bearing cells. Specific competitive elution of the endogenous Ig with heterologous nonimmune IgG established that the endogenous Ig was bound through the Fc gamma R. Tumor-associated Fc gamma R-positive, Ig-bearing cells could be detected with soluble antigen-antibody complexes, and mononuclear phagocytes to which the exogenous complexes were bound expressed Fc gamma R at a level significantly above normal. The role of this macrophage-associated Ig in determining the level of interaction between host cells and the tumor remains to be determined.

Animals↗