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Biomedical subjects

S Richmond

Publications and source records attributed to S Richmond.

At least 109 records · Page 6Linked to original sources
PubMed1991

Kainate and quisqualate effects on rat presynaptic cortical receptors are metabotropic and non-additive.

The effects of quisqualate and kainate on synaptosomal inositol phosphate (InsP) labelling, 45Ca influx and intrasynaptosomal free calcium ([Ca2+]i) were investigated. Each agonist caused a concentration-dependent increase in both [Ca2+]i and InsP labelling: quisqualate, however, produced significantly larger responses in both parameters and at lower EC50 values. Neither quisqualate or kainate significantly affected 45Ca influx into synaptosomes, indicating that the observed increases in [Ca2+]i were due to mobilisation from intracellular stores. The concentration-dependent increases in [Ca2+]i promoted by quisqualate and kainate were monophasic, whereas the increases in InsP formation fitted well to a biphasic curve. The EC50 values suggest that both kainate and quisqualate initially mobilise calcium from inositol 1,4,5-trisphosphate (Ins 1,4,5-P3)-sensitive stores and that the resultant increases in [Ca2+]i will, above a certain threshold, promote further increases in InsP production by stimulation of Ca(2+)-dependent phospholipase C. When saturating concentrations of kainate and quisqualate were used in combination, the effects on both InsP labelling and [Ca2+]i were not additive but were slightly higher than those produced by kainate alone: combined administration of the two agonists had no effect on 45Ca influx. These results suggest that kainate acts as a partial agonist at the presynaptic quisqualate metabotropic glutamatergic receptor.

Animals↗
PubMed1991

Quality control in orthodontics: indices of treatment need and treatment standards.

Two reliable and valid occlusal indices have been developed to assess treatment need (Index of Treatment Need, IOTN) and the standard of treatment (The PAR Index, Peer Assessment Rating). The IOTN assesses both dental aesthetics and dental health need. The PAR index provides a single summary score for the overall alignment and occlusion. The difference between the pre- and post-treatment scores reflects the degree of improvement and the success of orthodontic intervention and active treatment. Several practical uses of the indices are described: the estimation of treatment need in an unselected and a referred population and the assessment of the standard of treatment in the Hospital and General Dental Services. It has been suggested that the use of the occlusal indices would offer several advantages: (1) uniformity in prescribing patterns, (2) safeguards for the patient, (3) patient counselling and (4) monitoring and promoting standards.

Discriminant Analysis↗
PubMed1991

Quality control in orthodontics: factors influencing the receipt of orthodontic treatment.

The factors which influence the uptake of orthodontic treatment are reviewed with respect to the features and aspirations of the consumers (patients and parents) and the providers (dentists, orthodontists and health system). It appears that the assessment of orthodontic treatment need is influenced by many variables relating to opportunity and demand for treatment; this results in a marked lack of uniformity in treatment uptake.

Adolescent↗
PubMed1991

Quality control in orthodontics: risk/benefit considerations.

The literature concerning risk/benefit appraisal for orthodontic treatment is reviewed with respect to factors which influence dental health, social psychological well-being and the harmful effects of orthodontic treatment. There is little evidence to suggest that the absence of malocclusion is associated with a measurably higher self-esteem and life fulfillment, or with major advantages for dental health, except for a limited number of traits. With regard to treatment, small risks of iatrogenic harm exist, while the effects of partial or total failure of treatment, and the lack of long-term stability of results should not be underestimated.

Adolescent↗
PubMed1990

Trauma of treatment failure: a case report.

A large overjet is a well-recognised predisposing factor to traumatic injuries of upper incisor teeth. In order to reduce this risk factor, early reduction of an increased overjet has been recommended. This was attempted, but unfortunately was unsuccessful and further trauma resulted in loss of the upper central incisor teeth.

Child↗
PubMed1989

Pregnancy outcome at 24-31 weeks' gestation: mortality.

A study of all the mothers in the Northern region in 1983 whose pregnancies ended at between 24 and 31 weeks' gestation was undertaken. These pregnancies accounted for 1.3% of all the births and 44% of all the fetal and neonatal deaths in pregnancies that lasted more than 23 weeks. Most of the 389 singleton deliveries without malformations between 24 and 31 weeks were caused by spontaneous premature labour (n = 119, 31%), placental abruption (n = 79, 20%), pre-eclampsia (n = 56, 14%), and premature rupture of membranes (n = 48, 12%). The percentages of babies alive at the onset of delivery who survived the neonatal period were 66, 84, 78, and 73, respectively and the percentages of neonatal survivors with severe disabilities were 19, 13, 3, and 6, respectively. A further 65 (17%) of these babies died before the onset of labour for no obvious reason. The mode of delivery did not correlate with the outcome once the period of gestation at delivery was taken into account. The results highlight the inadequacy of the perinatal mortality index currently used in the United Kingdom, which identified 10.7 deaths/1000 registered births in 1983; 20% of the babies delivered at 24-31 weeks were excluded by this index because the birth went unregistered, as were 21% of all the babies born alive who died before discharge. An index that accounted for all babies weighing 500 g or more at birth irrespective of the period of gestation, and all neonatal (0-27 days) deaths, would be more appropriate and would bring reporting more into line with recommended international practice.

Congenital Abnormalities↗
PubMed1989

Pregnancy outcome at 24-31 weeks' gestation: neonatal survivors.

All surviving babies of less than 32 weeks' gestation born to mothers resident in the Northern region in 1983 were assessed. No baby was lost to follow up, and 230 long term survivors were assessed when 2 years old, by a single observer. Among 248 neonatal survivors, severe disability was present in 10 of the 37 at 24-27 weeks' gestation (27%) and in 18 of the 211 at 28-31 weeks' gestation (9%). On average the surviving babies required 27 days and seven days of intensive care nursing respectively. Babies who were ventilated for more than two weeks and babies who had neonatal fits had a poor prognosis. Because of postneonatal deaths only 20 of the 230 long term survivors of less than 32 weeks' gestation were severely disabled (9%). Comparable data were obtained for all babies weighing 1500 g or less at birth, irrespective of their gestational age. Severe disability was seen in eight of the 49 neonatal survivors (16%) who had weighed 500-999 g at birth, and in 17 of the 171 survivors (10%) who had weighed 1000-1499 g. The 10 neonatal survivors who had weighed exactly 1500 g at birth were all well. Only 18 of the 212 long term survivors (8%) who had weighed 1500 g or less at birth were severely disabled. Because the period of gestation is the only variable known to the obstetrician before delivery, and disability correlates better with gestation than birth weight, future studies should concentrate on relating morbidity, mortality, and the cost of neonatal care to gestation rather than weight at birth.

Developmental Disabilities↗
PubMed1989

An assessment of the fit of a parabolic curve to pre- and post-treatment dental arches.

Study casts of the teeth are routinely used for diagnosis and to assess treatment change: the crowding of the teeth or shortage of space available within the dental arch is usually assessed visually. A full cast analysis program has been developed previously, making use of the three-dimensional Reflex Plotter linked to a computer. This study examines the validity of the fit of computer generated parabolic curves to dental arches, as performed in the measurement of crowding. Using a visual analogue method it was found that the parabola appeared to fit lower post-treatment dental arches best. However, reservations regarding the fit of symmetrical curves are expressed and other solutions suggested.

Dental Arch↗