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Biomedical subjects

C E Parkinson

Publications and source records attributed to C E Parkinson.

At least 19 recordsLinked to original sources
PubMed2001

A new method of evaluating posterior occlusion and its relation to posttreatment occlusal changes.

The purpose of this study was to assess the relationship between posterior occlusion and posttreatment changes in other occlusal variables. Pretreatment (T1), posttreatment (T2), and postretention (T3) records were obtained for 49 Class I (n = 23) and Class II (n = 26) extraction cases. Overbite, overjet, mandibular incisor irregularity, right and left molar deviations, midline deviation, and mandibular arch length were measured, and occlusal registrations were made of each set of dental casts. The proximity of posterior occlusal surfaces was measured as the contact or near-contact areas at or below 300 microm thickness, based on the optical densities of scanned images of the posterior occlusal registrations. The treatment changes for overbite, overjet, right and left molar deviation, and arch length were significantly greater in the Class II group, and the reductions in incisor irregularity were greater in the Class I group. No other class differences were found. Overbite, overjet, and incisor irregularity increased after treatment, and arch length continued to decrease, with no significant class differences. Contact and near-contact areas at or below 300 microm constituted 7% of the functional occlusal table for both classes at the end of treatment, having decreased significantly in both groups (21% in Class I and 29% in Class II) during treatment. Because contact and near-contact areas increased in some patients and decreased in others, there were no significant posttreatment changes. Negative correlations were found between contact and near-contact areas at T2 and changes in overjet from T2 to T3, and between contact and near-contact areas at T3 and changes in overbite from T2 to T3. No relationships were found between posterior contact and near-contact area and incisor irregularity. We concluded that (1) the area of actual and near contacts at or below 300 microm decreased significantly with treatment, indicating that, despite excellent treatment results by conventional standards, the proximity of posterior occlusal surfaces lessened; (2) the proximity of the posterior occlusal surfaces should not be expected to increase posttreatment; (3) posttreatment contact and near-contact areas may be factors in overbite and overjet stability; and (4) posttreatment contact and near-contact areas are not related to incisor irregularity.

Adolescent↗
PubMed1986

Behavioural differences of school-age children who were small-for-dates babies.

Twenty-one children aged between five and nine years who were small for gestational age (SFD) at birth and whose intra-uterine head growth was shown by ultrasonography to be slowing before 35 weeks were observed in a special room, using video-cameras. Their behaviour was compared with that of 21 matched control children who had had normal birthweight. The children in the SFD group were quieter, more compliant and less active than the control group, and their play behaviour suggested that they were less advanced developmentally. The behaviour of the mothers of the SFD group showed that they were aware of their child's problems and tried to compensate for it by teaching the child while they were waiting for the observational session to start, by sitting closer to the child during a drawing test, and by using more words to explain it.

Body Height↗
PubMed1984

Non-protein bound zinc concentration in human plasma and amniotic fluid measured by ultrafiltration.

Using an ultrafiltration technique, apparent non-protein bound (NPB) zinc concentrations in plasma were found to be 2.2 +/- 0.2 (SEM) microgram Zn/l (10 observations) in normal males, 1.6 +/- 0.3 (10) micrograms/l in normal females and 1.2 +/- 0.2 (10) micrograms/l in pregnant mothers during their 16th week of gestation. These values are about 0.2% of the total plasma zinc concentrations, at least five-fold less than previous estimates. In amniotic fluid, the NPB-zinc concentration was 12.6 +/- 0.4 (10) micrograms/l, 5-10 times that of normal plasma, though the total zinc concentration (100 +/- 30 micrograms/l) was only one tenth that of plasma. When plasma or amniotic fluid samples were ultrafiltered without precaution against CO2 loss, their NPB-zinc concentrations increased, suggesting that pH changes alter zinc binding. The low concentration of NPB-zinc in plasma explains the low urinary excretion of zinc observed by others and would be expected to restrict the entry of zinc into cells.

Adult↗
PubMed1982

Research note: rating the home environment of school-age children; a comparison with general cognitive index and school progress.

A method of rating the home environment of primary school children is described. It was used in a study of 20 children whose cognitive abilities and school progress were also assessed. Aspects of home life which were found to be significantly correlated with the child's performance were parental encouragement for the child's achievement, activeness, creativity and verbal participation; a family interest in intellectual pursuits and education; family rules or control of the child. Some items were negatively correlated with children's performance.

Achievement↗
PubMed1982

Vitamin A concentration in amniotic fluid and maternal serum related to neural-tube defects.

The vitamin A concentration of amniotic fluid and maternal serum was measured during the second trimester of pregnancy in 106 women, 12 of whom had a baby with a neural-tube defect. In these 12 pregnancies the amniotic fluid vitamin A concentration was significantly higher than in 94 normal pregnancies. There was a highly significant correlation between amniotic fluid vitamin A and both zinc and alpha-fetoprotein (AFP) levels. The maternal serum vitamin A levels were also significantly related to serum zinc levels. Women with a raised serum AFP level, but a normal baby, had significantly higher amniotic fluid vitamin A levels and significantly lower serum vitamin A levels compared with those in women with normal serum AFP levels.

Adult↗
PubMed1981

Electronic measurement of locomotion by means of pressure-sensitive floor mats.

This paper describes a method of adapting an observation room to record a child's position in the room and to give an index of the amount of locomotion. The adaptation consisted of under-carpet pressure mats, linked electronically to digital counters. This recording system showed a highly significant correlation with observational measurements of the same aspects of behaviour. It has potential as an aid in the diagnosis of abnormal behaviour states.

Child↗
PubMed1981

School achievement and behaviour of children who were small-for-dates at birth.

School-teachers were asked to assess the school achievement and behaviour of 45 children who had been small-for-dates (SFD) at birth, and of 19 control children who had had a normal birthweight. The SFD children were divided into groups according to the stage in gestation at which slow head-growth began. Those whose head growth had slowed before 26 weeks gestation achieved less well at school than those who had had no evidence of slow intra-uterine head-growth. Their teachers also thought they were less able to concentrate. Boys (but not girls) whose head growth had slowed between 27 and 34 weeks gestation also had problems at school. The authors conclude that school achievement and behaviour of children who were small-for-dates at birth is related to the severity of slow growth before birth, the sex of the child and the social class of the parents.

Achievement↗
PubMed1979

Maturity of fetal lungs tested by production of stable microbubbles in amniotic fluid.

Lung surfactant in amniotic fluid, and hence the maturity of the fetal lungs, can be assessed by observation of stable microbubbles (less than 15 micron diameter). Bubbles are formed by agitation with a Pasteur pipette and examined in hanging drops under the 10 x power of a microscope. Either after a count of bubbles, or after a general survey of hanging drops, the fluid is given a stable microbubble rating. A 'strong' rating indicates that the idiopathic respiratory distress syndrome will not occur after delivery, and that the lecithin/sphingomyelin ratio will indicate maturity. Complete absence of stable microbubbles suggests a high risk of respiratory trouble for the newborn infant, as does a weak or lower rating in the 30 to 37 week gestational age group. The test takes 5 to 10 minutes to perform, is cheap and easy, is not affected by blood, but may be affected by meconium. If a 'strong' rating is found, measurement of the L/S ratio can safely be omitted.

Amniotic Fluid↗
PubMed1978

Bubble clicking in pharyngeal aspirate compared with lecithin/sphingomyelin ratio.

Tracheal fluid flows into the pharynx, so surfactant can be measured in pharyngeal aspirate. The walls of bubbles in air-free water show rhythmic movements (bubble clicking) if they contain surfactant. Babies with respiratory distress syndrome (RDS) have very little lung surfactant which can be shown by a low lecithin/sphingomyelin (L/S) ratio. To investigate surfactant in newborn babies we analysed 125 pharyngeal aspirates for the L/S ratio and bubble clicking. Both tests became more positive towards term and were related to the incidence of RDS. Babies with birth asphyxia or mild respiratory difficulties had lower L/S ratios and less clicking than normal babies. Both investigations could be used to chart the course of RDS. The L/S ratio is a chemical measurement of surfactant. Bubble clicking, which takes only a few minutes, demonstrates surface tension effects.

Humans↗
PubMed1977

Fatty acids of phospholipids in human neonatal lung surfactant.

The fatty acid chains of lecithin, phosphatidyl ethanolamine (PE), and phosphatidyl dimethylethanolamine (PDME) in human neonatal alveolar washes were analyzed. Both alpha- and beta-palmitic acid increased with gestational age on all phospholipids analyzed. No evidence for high concentrations of myristic acid was found on any phospholipid. Babies who were stillborn or who had died of hyaline membrane disease (HMD) had lower proportions of beta-lecithin palmitic acid when compared with babies who breathed normally before death. In the HMD group these levels were significantly lower.

Fatty Acids↗
PubMed1976

The lecithin/sphingomyelin (L/S) ratio in twin pregnancies.

The lecithin/sphingomyelin (L/S) ratio has been estimated in the amniotic fluid from 20 patients with a twin pregnancy. The values in each pair of amniotic fluids were closely related. If amniotic fluid from one sac only is available, it is suggested that a ratio of 2-5:1 is taken as the lower limit to predict the functional lung maturity of both twins.

Amniotic Fluid↗