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Biomedical subjects

J C Shaw

Publications and source records attributed to J C Shaw.

At least 73 records · Page 4Linked to original sources
PubMed1979

The EEG and differential diagnosis in psychogeriatrics.

A model for differentiating cerebral dysfunction in senile, arteriosclerotic dementia, and depressive states is proposed on the basis of electrocortical topographic measures of EEG coherence. Bipolar EEGs were recorded from central, parietal, occipital and temporal areas in 24 elderly patients with a firm clinical diagnosis of senile dementia, senile arteriosclerosis or depression. Power and coherence spectra were computed on 20 second epochs recorded during eyes open, eyes closed and photic stimulation. Significant group differences were reported in both power and coherence measures. Power results were uniform for all channels but coherence values differed significantly with derivation. The best discriminator between groups was EEG coherence estimates between right parietal and temporal derivation. Correlations between clinical symptomatology and EEG coherence supported the direction of the discrimination between groups. The EEG coherence function is discussed as a potential measure of neuro-functional pathology in psychiatry.

Aged↗
PubMed1978

Field dependence, laterality and the EEG.

There is evidence that an individual's 'cognitive style' is related to lateralization of function in the brain, and that this in turn is associated with characteristic EEG coherence spectra. We tested the hypothesis that field dependence (a measure of cognitive organization) and hand preference (a measure of functional organisation) relate to EEG coherence measures in a specific way. The predicted associations were based on the proposal that right preferent individuals have a more specific, and left preferents a more diffuse, system of functional units in the cortex. The association between alpha band resting EEG coherence (sampled on two occasions for both hemispheres from 12 right and 12 left preferent individuals), field dependence (Nyborg's criterion of frame dependence on a rod and frame test), and laterality scores (questionnaire and manual performance), was measured by Kendall's coefficient of concordance (W). Significant associations support the proposed model except for coherence within the left preferents' right hemisphere. It is argued that the right hemisphere is more specifically organised in strong sinistrals than the general model would predict. These and other results support the use of EEC coherence measures in the study of cerebral functional organisation.

Adult↗
PubMed1978

The EEG, brain function, and Thomson's sampling theory.

If the EEG is regarded as a measure of functional organisation in the brain, it may yet be possible to use it as an independent variable in psychological studies. The method of Maxwell et al. (1974) suggest how this relationship may be quantified. These authors develop the hypothesis that EEG power is proportional to p, the number of brain components involved in cognition. However, evidence is reviewed here to suggest an alternative hypothesis for the case of EEG alpha activity, namely that power is proportional to (1--p).

Alpha Rhythm↗
PubMed1978

The effect of iron supplements and blood transfusion on iron absorption by low birthweight infants fed pasteurized human breast milk.

Using serial metabolic balances, iron absorption was measured in six preterm infants (mean gestational age 29 weeks), and two fullterm small for gestational age (SGA) infants, between day 10 and 70 after birth. They were all fed breast milk. Iron supplements (2.5--13 mg/kg day) were given from day 30. Three preterm infants received blood transfusions for anemia. During the first 30 days of life iron balance was negative in the preterm infants (mean +/- SEM = -0.10 +/- 0.02 mg/kg day) and positive in the full term SGA infants (mean +/- SEM = 0.098 +/- 0.02 mg/kg day). In infants who were not tranfused, absorption of supplementary iron was a linear function of iron intake, and corresponded closely to 34% absorption. An iron intake of 5--6 mg/kg day resulted in the absorption of amounts of iron close to those being laid down in utero. Blood transfusion was followed by a reduction in iron absorption; in two cases it became negative, becoming positive again as the hemoglobin fell below about 12.0 g/100 ml. These data show that a mechanism exists in preterm infants for the control of iron absorption which does not operate at the hemoglobin concentrations that prevail in such infants, unless they are transfused.

Absorption↗
PubMed1977

The EEG as a measure of cerebral functional organization.

Evidence suggests that anomalies of functional organization in the brain may be present in some psychiatric disorders and that EEG differences between psychiatric patients and appropriate control groups may depend on them. It is therefore of practical importance to develop further ways of examining the association between the EEG and such organization. The change in inter-hemisphere coherence (a measure of EEG synchronicity) in the alpha frequency band when carrying out a task is shown to discriminate a group of II right from II left preferent normal individuals. Since right and left preference is associated with differences in cerebral functional organization, the coherence measure may be a useful way of studying this feature of psychiatric illness.

Brain↗
PubMed1976

Cerebral function and the EEG in psychiatric disorder: a hypothesis.

Independent studies which showed a difference between the EEG frequency spectra of test and control groups have been compared. Some of the test groups included schizophrenic patients, others comprised groups with dyslexia, reading disability and left preference. The EEG differences between the test and control groups are shown to be similar across the studies. It is suggested that the common attribute of the test groups relates to the functional organisation of the brain and that investigation of EEG correlates of this phenomenon may be of value to research into the biological basis of psychiatric illness.

Action Potentials↗
PubMed1976

Evidence for defective skeletal mineralization in low-birthweight infants: the absorption of calcium and fat.

Using serial metabolic balance techniques, the absorption and retention of calcium and the absorption of fat have beem measured over the first 30 to 70 days of life in 11 preterm and 2 full-term light-for-dates infants. They were fed either full-cream cow's milk, half-skimmed cow's milk, the proprietary filled milk S.M.A., or breast milk. The values for calcium intake, absorption and retention were compared with the rate of accumulation of calcium by the fetus in utero, which was calculated from published data on the chemical composition of fetal bodies. Infants fed breast milk had an absolute dietary deficiency of calcium. Those fed other milks ingested sufficient but they did not absorb enough. Though calcium absorption increased with increasing postnatal age, intrauterine rates of calcium retention were never achieved on any of the milks. The average retention of calcium by preterm infants as a percentage of intrauterine accumulation was, for cow's milk 38%, for S.M.A. 27%, and for breast milk 17%. The full-term light-for- dates infants absorbed and retained more calcium than the preterm infants; it was on average 52% of the amount accumulated by the human fetus for an equivalent weight gain. The average absorption of fat by preterm infants was, from the cow's milk preparations 55%, from S.M.A. 61%, and from breast milk 84%. The light-for-dates infants absorbed on average 87% of the breast milk fat. There was no evidence that the amount of calcium absorbed was materially influenced by fat malabsorption. The principal determinants of the amount of calcium absorbed were the length of gestation and postnatal age of the infant.

Age Factors↗
PubMed1973

Mineral content of brands of milk for infant feeding.

The amounts of sodium, potassium, phosphorus, and nitrogen in several brands of milk used for infant feeding have been measured, and the concentrations of these substances in the reconstituted milks calculated. The known variation in the electrolyte content of cows' milk and the addition of minerals in the manufacture of many types of milk foods may account for the variation in the content of these substances, but the addition of neutralized whey in the manufacture of Trufood Formula 4 increased the concentration of sodium to a level twice that found in undiluted cows' milk. We think that details of all mineral additions to milks used for infant feeding should be made readily available and that the mineral content of the powders or liquids should be printed on the containers and expressed both in mg/100 g and mEq/kg. Milks reconstituted to a composition close to that of cows' milk present large osmotic loads to the kidneys, and may endanger water balance in some circumstances. This risk can be reduced by a greater dilution with water.

Animals↗