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Biomedical subjects

A McLean

Publications and source records attributed to A McLean.

At least 109 records · Page 6Linked to original sources
PubMed1989

General versus disease-specific measures. Further work on the Sickness Impact Profile for head injury.

Three modifications devised to make the Sickness Impact Profile more sensitive to head injury are evaluated in 202 head-injured and 132 general trauma patients 1 month and 12 months after injury. The modifications consist of adding items, deleting nonapplicable items, and reweighting areas of function. Each of the modifications, and especially all three combined, slightly but significantly improve discrimination of head-injured and comparison subjects and increase correlations with neurologic and neuropsychologic severity indexes. These slight improvements occur more often at 12 months than at 1 month and among those without rather than with pre-existing conditions. No improvements are found in the ability to classify patients into subgroups. The modifications fail to make improvements sufficiently large or consistent to provide a practical advantage over the SIP. The standard SIP provides a reasonable measure of psychosocial functioning following head injury. It relates to head injury and other system injury severity and reflects recovery with time. The SIP score relates to emotional functioning even after injury severity has been taken into account. Until other factors, such as emotional status and responses style, are better controlled, little benefit is likely to be obtained from creating disease-specific psychosocial measures.

Activities of Daily Living↗
PubMed1988

Development and evaluation of modifications to the Sickness Impact Profile for head injury.

Three modifications were made to the Sickness Impact Profile, a behavior-based measure of health status, to improve its sensitivity to the effects of head injury. (1) Additional items were included to capture head injury sequelae and behaviors typical of young adults, the age group to which head injury most frequently occurs. (2) Subjects individually excluded behaviors irrelevant to them, thus allowing the score to better reflect injury-related changes. (3) The different areas of functioning on the Sickness Impact Profile were reweighted to reflect global judgments of the construct's contribution to overall functioning rather than the sum of the item contributions. Only the first modification is head-injury specific. The others, are relevant to any disease or injury. The performance of the modifications was evaluated in a longitudinal study of 102 head injured and 102 comparison subjects tested at 1 and 12 months after injury. The evaluation of the modifications was based on their ability to distinguish head injury from comparison subjects and on the strength of their relationship with measures of brain dysfunction. Despite a few statistically significant improvements in discrimination, differences of a practical degree were not obtained. The standard Sickness Impact Profile performed well and is recommended for evaluation of day-to-day functioning in head injury studies.

Activities of Daily Living↗
PubMed1988

Significant intimal abnormalities in muscular pulmonary arteries of patients with early obstructive lung disease.

Substantial intimal changes, unrelated to aging, were found in resected lobes or lungs of 30 smokers with early obstructive lung disease (22 men, eight women: age range 46-74 years: forced expiratory volume in one second (FEV1)% predicted range 47-119%). Intimal area was measured using a digitiser and expressed as a proportion of the area enclosed by the internal elastic lamina (IEL), correcting for constriction (intima index). Arteries were subdivided into four size (length IEL) groups. For the smallest group (less than or equal to 600 micron length IEL) the mean intima index (II600) ranged from 0.09-0.34; half the values were greater than or equal to 0.20. Intimal abnormality was unrelated to the size or site of tumour or to macroscopic emphysema, and correlated weakly with pack years. II600 values were, however, significantly correlated with factors known to be affected by smoking such as alveolar wall surface area per unit lung volume, FEV1% predicted, and FEV1/FVC (forced vital capacity); these last two factors were also significantly associated with intimal abnormality in arteries measuring 601-1200 micron length IEL.

Age Factors↗
PubMed1988

CT measurements of lung density in life can quantitate distal airspace enlargement--an essential defining feature of human emphysema.

We used a computerized microscopic image analysis system to directly measure the surface area of distal air spaces in methacrylate-embedded blocks randomly selected from inflation-fixed lobes that were resected from 45 patients as treatment of their peripheral lung tumors. In 28 of these patients, a preoperative computer tomography (CT) scan, at 6 and 10 cm below the sternal notch, was used to generate frequency histograms of CT numbers (measured as EMI units), a measure of lung density, in pixels from the lung or lobe that was subsequently resected. A similar CT number histogram was also derived from the lateral two fifths of the area of lobe/lung that was to be resected. The EMI unit that defined the lowest fifth percentile of this latter histogram correlated (n = 28, r = -0.77, p less than 0.001) with the mean value of the surface area of the walls of distal airspaces per unit lung volume (AWUV) in the five 1 mm x 1 mm microscopic fields with the lowest AWUV values, out of the 20 to 35 such fields examined in each patient. In the 34 of the 45 patients in whom we also measured volume-corrected diffusing capacity (DLCO/VA), this also correlated (n = 34, r = 0.84, p less than 0.001) with this value of AWUV, which measures the surface area of airspaces distal to the terminal bronchioles--reflecting an increase in airspace size, a defining characteristic of emphysema. However, a low DLCO/VA is nonspecific, whereas an abnormally low regional lung density is more likely to be specific for emphysema. In addition, highlighting those pixels of the CT display with low CT numbers (i.e., EMI units -500 [air] to -450, where zero = water) can locate areas of macroscopic emphysema, as shown by subsequent pathologic examination. Thus the quantitative CT scan can diagnose, quantitate, and locate mild to moderate emphysema, in humans, in life, noninvasively.

Aged↗
PubMed1988

Comparison of reading and listening-reading techniques for administration of PIAT Reading Comprehension subtest: justification for the bypass approach.

The Peabody Individual Achievement Test (PIAT) Reading Comprehension subtest was administered to a group of 23 learning disabled children in Grades 5 through 7 who had been classified by the clinical Lexical Paradigm as good readers or poor readers. Using standardized test administration, 14 poor readers scored substantially below the 9 good readers; however, when the child was allowed to listen and read silently while the test item was read aloud, poor readers showed marked improvement in performance compared to only moderate improvement shown by the good readers. This difference in improvement between the groups was significant and resulted in poor readers achieving performance similar to that of the good readers administered the test in the standard manner.

Achievement↗
PubMed1987

Aluminium-related osteomalacia: response to reverse osmosis water treatment.

It is generally accepted that aluminium induces osteomalacia in chronic hemodialysis patients by binding to the calcification front, thereby inhibiting mineralization of osteoid. Because this form of osteomalacia is vitamin D resistant, the condition has often been assumed to be irreversible, although promising results have been achieved recently by using a chelating agent for removal of aluminium from the skeleton. In this paper we present four chronic hemodialysis patients with aluminium toxicity and histologic osteomalacia in whom the mineralization defect greatly regressed after the use of reverse osmosis treated-water for dialysis, but without further treatment. In three other patients, also with aluminium toxicity and histologic osteomalacia, similarly treated, the histological severity of the osteomalacia remained static. Those patients in whom bone mineralization status improved developed hyperparathyroidism after reverse osmosis water-treatment, whereas the static patients remained euparathyroid. The results suggest that resolution of aluminium related osteomalacia may occur with reduction in dialysis fluid aluminium, and that parathyroid hormone plays a role in the healing of aluminium related osteomalacia. The therapeutic implications are twofold: attempts to remove all traces of hyperparathyroidism may be detrimental to the bone mineralization status; and stimulation of the parathyroid glands by means of a mild reduction in dialysis fluid calcium may be of value in the management of those cases with persistent osteomalacia and low bone turnover.

Adult↗
PubMed1987

Memory and head injury severity.

One hundred and two consecutive head injured patients were studied at 1 and 12 months after injury. Their performances were compared with a group of uninjured friends. The results indicate that impairment in memory depends on the type of task used, time from injury to testing, and on the severity of head injury (that is, degree of impaired consciousness). Head injury severity indices are more closely related to behavioural outcome early as compared with later after injury. At 1 year, only those with deep or prolonged impaired consciousness (as represented by greater than 1 day of coma, Glasgow Coma Scale of 8 or less, and post traumatic amnesia of 2 weeks or greater) are performing significantly worse than comparison subjects.

Adult↗
PubMed1986

Family therapy workshops in the United States: potential abuses in the production of therapy in an advanced capitalist society.

A market for family therapy workshops has mushroomed in recent years. Treatment of families by therapists conducting such workshops, however, can be dispassionate and dehumanizing. Using the distinction between curing and healing, I do not question the curative potential of family therapy, but I question whether this kind of doctor/patient interaction promotes healing. Also, by demonstrating how the systems model tends to objectify patients and alienate therapists from those they treat, this paper challenges claims that family therapy recognizes the social nature of illness. The dehumanizing treatment cannot be attributed solely to the therapists, but requires further interpretation by analyzing the biases of the therapy model, the commodified context of the workshops, and epistemological issues arising from the application of general systems theory to a social model of treatment. Family systems therapy shares epistemological features with biomedicine, and like the biomedical model, alienates therapists from patients. This alienation, ironically, can be even greater when the family systems model is used than in biomedical treatment. Finally, I suggest that family therapy workshops have grown in popularity because the mechanistic features of the treatment model, drawn largely from cybernetics, promote the production and reproduction of a form of therapy compatible with the emphasis on 'functional health' favored in an advanced capitalist society.

Cybernetics↗
PubMed1986

Neuropsychological and psychosocial consequences of minor head injury.

Twenty subjects with minor head injury were compared to an uninjured group at 1 and 12 months after injury on a battery of neuropsychological and psychosocial measures. The results indicate that single minor head injury in persons with no prior compromising condition is associated with mild but probably clinically non-significant difficulties at 1 month after injury. Disruptions of everyday activities, however, are extensive with other system injuries significantly contributing to these problems. Recent reports in the literature may represent overestimation of head injury related losses due to lack of control for the effects of pre-injury characteristics and other system injuries.

Activities of Daily Living↗
PubMed1986

A diagnostic approach to developmental specific learning disorders.

Children and adolescents who are not doing well in school are often referred to physicians for evaluation. Many of these children have average or above-average intelligence but are academically frustrated, low achievers. Parents state that although they are convinced that their child is bright, he or she does not seem to learn, and does not behave acceptably in school and at home. Results of the usual pediatric and neurologic examinations are frequently unrevealing. In evaluating children who are doing poorly in school, the clinician must determine whether the child has a developmental specific learning disorder and whether primary affective illness, disturbed vigilance, or hyperactivity complicates the picture. Children who are intelligent but failing in school frequently manifest either one or several of these conditions. Although there are reasonably well-established criteria for affective illness in children, clinically useful criteria for evaluating the variety of childhood learning problems have not been available. We present criteria for the diagnosis of developmental specific learning disorders and briefly mention some aspects of management and treatment. We also describe a primary disorder of vigilance that becomes manifest in school, worsening the learning and performance process, which is further worsened by affective illness.

Adolescent↗
PubMed1986

Neuropsychologic outcome at one-month postinjury.

Neuropsychologic outcome at one-month postinjury was investigated in a group of 102 adult patients with head injury representing a broad spectrum of severity. A group of friends of the patients with head injury was selected for comparison purposes. A comprehensive battery of measures assessing various abilities determined the adequacy of neuropsychological functions. Results support the following conclusions: head injury is associated with early deficits observable on measures assessing a broad spectrum of functions, ranging from simple to complex and motoric to abstraction skills; use of appropriate control groups is essential for determining head injury related deficits; the degree of neuropsychologic deficits depends on the severity of head injury; and the severity indices of time to following commands and depth of coma relate more closely and systematically to adequacy of one-month neuropsychologic outcome than does retrospectively assessed posttraumatic amnesia.

Adolescent↗
PubMed1985

New method for quantitating the medial component of pulmonary arteries. Factors affecting the measurements.

The study objectives were to determine the effect of several factors related to tissue preparation on the relationship between medial area and size of the muscular pulmonary artery (defined in terms of total length of internal elastic lamina). This relationship took the form y = Axb that was linearized by plotting the square root of medial area against artery size. Complete distention of pulmonary arteries by an injection medium caused the internal elastic lamina to stretch by a factor of approximately 1.5. The relationship between medial area and artery size was unaffected by either the pressure method used for lung inflation/fixation or the tissue-embedding medium. Tissue shrinkage was considerable with paraffin embedding and negligible with glycol methacrylate. More arteries were considered measurable in glycol methacrylate-embedded tissue.

Aged↗
PubMed1984

Diagnosis of pulmonary emphysema by computerised tomography.

Eleven patients with peripheral bronchial carcinoma had computerised tomographic (CT) scans before operation. The resected specimens from six of these patients showed mild centri-acinar emphysema. Preoperatively the two groups had not differed significantly in spirometric findings or lung volumes. The frequency distribution curves of EMI numbers within the lung fields of patients who proved to have centri-acinar emphysema differed significantly from those of the group who did not, there being more pixels in the EMI range -450 to -500 in the emphysematous group (p less than 0.001). Detailed assessment of lung density by CT scanning may be useful in the diagnosis of emphysema in life.

Adult↗
PubMed1984

Effect of co-ingestion of fat on the metabolic responses to slowly and rapidly absorbed carbohydrates.

The present study examined the acute effects of co-ingestion of fat (37.5 g) on the post-prandial metabolic responses to 75 g of carbohydrate which was either slowly absorbed (lentils) or rapidly absorbed (potatoes). Co-ingestion of fat resulted in a significant flattening of the post-prandial glucose curves, the effect being more pronounced for the rapidly absorbed potatoes. This was probably due to delayed gastric emptying. However, the post-prandial insulin responses to either carbohydrate were not significantly reduced by fat, suggesting that the insulin response to a given glucose concentration was potentiated in the presence of fat. The gastric inhibitory polypeptide (GIP) responses to both carbohydrates were greatly increased in the presence of fat. To investigate further the possible roles of GIP in the entero-insular axis, a 5-g bolus of glucose was injected intravenously 1 h after lentils +/- fat. This was sufficient to raise the glucose levels above the threshold reported for GIP to potentiate insulin secretion. However, despite the large differences in circulating GIP levels, the insulin response to glucose was not affected by the presence of fat. These results suggest that (1) the rate of absorption of carbohydrate is a major determinant of post-prandial metabolic responses even in the presence of fat, (2) fat-stimulated GIP secretion does not potentiate glucose-induced insulin secretion, and (3) the potentiation of the insulin response to glucose when carbohydrate is co-ingested with fat is consistent with the well-documented insulin resistance associated with high fat diets.

Absorption↗
PubMed1984

A possible molecular basis for strain specific immunity to malaria.

A 250 kDa antigen implicated in the induction of protective immunity to Plasmodium chabaudi was examined with a panel of 11 monoclonal antibodies in cloned parasite lines. 2 antibodies cross-reacted with the different parasite lines while 9 were specific for one line. This antigenic diversity was correlated with major differences in one dimensional peptide maps between the purified antigen from different lines of parasites. The peptide maps also revealed some apparently conserved structure which may have been responsible for the antigenic cross reactivity. Using cloned lines of P. falciparum and a second series of monoclonal antibodies, similar antigenic and structural diversity was evident in the equivalent antigen from the important human pathogen. These findings are discussed with relationship to the induction of protective immunity to malaria.

Animals↗