Parentage analysis using RAPD PCR.
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Animals↗
Biomedical subjects
S M Williams
Publications and source records attributed to S M Williams.
Light and electron microscopic characterization of dopamine-immunoreactive axons in human cerebral cortex.
The distribution and synaptic connections of dopamine axons were studied by light and electron microscopy in human cerebral cortex. For this purpose, dopamine immunoreactivity was characterized in apparently normal anteriolateral temporal cortex, which was removed to gain access to the medial temporal lobe during tumor excision or treatment of epilepsy. Nissl sections showed this to be granular neocortex. Dopamine fibers were distributed throughout this cortex, although there were relatively more fibers in layers I-II and in layers V-VIa, compared to layers III-IV and VIb, resulting in a bilaminar pattern of labeling. In all layers, fibers were seen to form numerous varicosities, and to vary in size from thick to very fine. Fibers were relatively straight, sparsely branched and were oriented in various planes within the cortex. However, in layer I, they often ran parallel to the pial surface. In order to analyze the functional interactions of dopamine fibers, individual cortical layers were surveyed for dopamine synapses. These were usually symmetrical (Gray's type II), although 13% of them were asymmetrical. Approximately 60% of dopamine synapses were made with dendritic spines, and 40% with dendritic shafts, and this ratio was similar in all layers. On both spines and shafts, it was common to see dopamine synapses closely apposed to an unlabeled asymmetric input, suggesting a dopamine modulation of excitatory input. Some postsynaptic dendritic shafts had features of pyramidal cells, including formation of spines. Since pyramidal cells are the major type of cortical spiny neuron, they probably represent the main target of dopamine synapses in this cortex. There were also dopamine profiles apposed to membrane densities on unlabeled axon terminals, suggesting another type of synaptic interaction. These findings provide the first documentation of dopamine synapses in the human cortex, and show that they form classical synaptic junctions. The location of these synapses on spines and distal dendrites, and their proximity to asymmetric synapses, suggest a modulatory role on excitatory input to pyramidal cells.
Axons↗
The synaptology of parvalbumin-immunoreactive neurons in the primate prefrontal cortex.
Electron microscopy and immunocytochemistry with a monoclonal antibody against parvalbumin (PV) were combined to analyze the distribution and morphology of PV-immunoreactive (PV-IR) neurons and the synaptology of PV-IR processes in the principal sulcus of the macaque prefrontal cortex. Parvalbumin-IR neurons are present in layers II-VI of the macaque principal sulcus (Walker's area 46) and are concentrated in a band centered around layer IV. PV-IR cells are exclusively non-pyramidal in shape and are morphologically heterogeneous with soma sizes ranging from less than 10 microns to greater than 20 microns. Well-labeled neurons that could be classified on the basis of soma size and dendritic configuration resembled large basket and chandelier cells. A novel finding is that supragranular PV-IR neurons exhibit dendritic patterns with predominantly vertical orientations, whereas infragranular cells exhibit mostly horizontal or oblique dendritic orientations. PV-IR cells within layer IV exhibit a mixture of dendritic arrangements. Vertical rows of PV-IR puncta, 15-30 microns in length, resembling the "cartridges" of chandelier cell axons were most dense in layers II, superficial III, and the granular layer IV but were not observed in the infragranular layers. Cartridges were often present beneath unlabeled, presumed pyramidal cells. PV-IR puncta also formed pericellular nests around pyramidal cell somata and proximal dendrites, suggestive of basket cell innervation. PV-IR axons were occasionally observed in the white matter underlying the principal sulcus. Electron microscopic analysis revealed that PV-IR somata and dendrites are densely innervated by nonimmunoreactive terminals forming asymmetric (Gray type I) synapses as well as by fewer terminals forming symmetric (Gray type II) synapses. The majority of terminals forming symmetric synapses with PV-IR post-synaptic structures were not immunolabeled; however, some of these boutons did contain PV-immunoreactivity. PV-IR boutons exclusively form symmetric synapses and heavily innervate layer II/III pyramidal cells. PV-IR axon cartridges formed numerous axo-axonic synapses with the axon initial segments of pyramidal cells 15-20 microns beneath the axon hillock and also terminated on large axonal spines of the initial segment. Furthermore, we failed to observe a mixture of PV-immunoreactive and non-immunoreactive boutons composing a single axon cartridge. Pyramidal cell somata and proximal dendrites were also heavily innervated by PV-IR boutons forming symmetric synapses, again, consistent with basket cell innervation. In addition, PV-IR axon terminals frequently formed symmetric synapses with dendritic shafts and spines of unidentified neurons.(ABSTRACT TRUNCATED AT 400 WORDS)
Afferent Pathways↗
Quality control: an application of the cusum.
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Clinical Competence↗
Measuring care and dependency of elderly people in residential homes: an unreliable exercise.
OBJECTIVES: to determine the correlation between a scale measuring the amount of care required by people in rest homes and two scales, the Booth scale and the composite scale which measure dependency. To examine the scales for retest reliability. SUBJECTS: one hundred and twenty-five people aged 47 to 98 years, median age 84 years, living in seven rest homes in Dunedin. METHOD: subjects were assessed using the care, Booth and composite scales and the assessment repeated after four weeks. RESULTS: the care scale test-retest reliability based on rank order correlates was 0.86. For the physical care items retest reliability was high but supervision and the management of behavioural problems showed poor retest reliability. Correlation between the care scale and the two dependency scales was only moderate (composite scale 0.64, Booth scale 0.55). Behavioural problems and the time for supervision were assessed on the care scale only and it was these components which accounted for most of the poor correlation between the care and dependency scales. CONCLUSION: the time required for the management of behavioural problems and supervision for some people in rest homes was considerable. Measurement of this was difficult and made assessment of individual residents in homes unreliable.
Activities of Daily Living↗
Technique for revision of continent ileostomy.
A technique is described for revising an incompetent nipple valve of a continent ileostomy. The procedure involves preserving the incompetent valve and using it as a collar around the base of the new valve to improve function.
Adult↗
Molecular genetic analysis of Drosophila rDNA arrays.
Large repeated DNA arrays are a major component of the eukaryotic genome, but we know little about their internal organization. Understanding their architecture, however, is critical for describing genome structure and for inferring the mechanisms that shape it. One repeated family that is yielding a picture of how structure, function and recombination mechanisms come together is the ribosomal DNA (rDNA) of Drosophila melanogaster.
Animals↗
Cycling health beliefs, crash experiences and night cycling behaviour of 13 year olds.
The relationship of selected health beliefs to self-reported crash experiences, cycling at night and the use of tail-lights at night was examined for a sample of 730 13 years olds. The questions relating to cycling health beliefs were similar to those asked by Weinstein in his study of unrealistic optimism about susceptibility to a range of health problems. They included: vulnerability, worry, controllability, chance, barriers, seriousness, apprehension and safety. The majority of 13 year olds interviewed did not exhibit a strong optimistic bias regarding their vulnerability and skills as safe cyclists. In general the majority considered a crash involving a car would most likely be serious and only a minority said they were not worried about being involved in such a crash. In addition, the majority did not consider that crashes are a matter of chance or that there are significant barriers to adopting safety measures. They tended to consider the chances of being apprehended by a traffic officer for failure to use a tail-light at night as being low. Overall the univariate analyses failed to show a consistent pattern of relationships between health beliefs and the two cycling behaviours. The same was true for crash experiences. The joint effects of beliefs and crash experience on the use of a light at night were examined using logistic regression. The results suggest that the health beliefs work in an additive way as far as boys are concerned, but that they have very little influence on the behaviour of girls. The model for boys suggests that the variables have a relatively small influence on behaviour.
Accidents, Traffic↗
Distinguishing between persistent and transient impaired glucose tolerance using a prediction model.
Screening for impaired glucose tolerance (IGT) and Type 2 (non-insulin dependent) diabetes was carried out in 777 people and those with high blood glucose levels completed three 2-h oral glucose tolerance tests (OGTT). Blood lipid levels, fasting and 2-h insulin levels, body mass index, and blood pressure were also measured and family history of Type 2 diabetes recorded. Fifty people were identified with IGT and of these 21 were found to have persistent IGT and 29 transient IGT. A model including the variables body mass index, fasting and 2-h insulin levels, fasting triglycerides and family history of Type 2 diabetes was developed using the Speigelhalter-Knill-Jones weighting method to predict subjects with persistent IGT. This model could be useful in identifying people with persistent IGT and therefore eliminate the need for repeat OGTTs which are time consuming and expensive.
Blood Glucose↗
Dentures, prosthetic treatment needs, and mucosal health in an institutionalised elderly population.
A survey of 359 elderly residents of rest homes and geriatric hospitals in the Manawatu and Horowhenua regions showed that 80.5 percent were fully edentulous. Full upper and lower dentures were worn by 64 percent of the total sample, and 31 percent of the dentate group wore one or more partial dentures. Prosthetic treatment needs were dominated by full dentures: 18 percent of upper dentures and 26 percent of lower dentures were considered to need replacement. A further 24 percent of full lower dentures required relining. Only 7 percent of the dentures were named. One third of the subjects had mucosal lesions, the most common lesions being angular cheilitis (present in 18 percent of subjects), traumatic ulcers (14 percent), atrophic glossitis (12 percent), and leukoplakia (present in 8 percent of subjects). No malignant lesions were found.
Aged↗
Knowledgeable non-compliance with prescribed drugs in elderly subjects--a study with particular reference to non-steroidal anti-inflammatory and antidepressant drugs.
Knowledgeable non-compliance with non-steroidal anti-inflammatory drugs (NSAIDs) and antidepressant drugs was investigated in a community-based sample of elderly people. Everyone 70 years and over living in a defined area and taking one of the above drugs, and at least one other prophylactic or symptomatic drug, was studied. Non-steroidal anti-inflammatory drugs and antidepressant drugs are commonly regarded as symptomatic only and knowledgeable non-compliance is consequently high. They are also regarded as less important than drugs which produce no immediate relief of symptoms but which the patient recognizes as needing to be taken regularly to maintain health. In our study, compliance with non-steroidal anti-inflammatory drugs and antidepressant drugs was highest in those who were compliant with a prophylactic drug and were also taking a symptomatic drug. The greater the number of tablets the patient was taking the more likely he or she was to be compliant with the NSAID. Compliance with NSAIDs and antidepressant drugs requires clear label instructions and the patient knowing the purpose of the medication.
Aged↗
Competency and the colonoscopist: a learning curve.
The first 334 consecutive unassisted studies of a trainee colonoscopist were audited to analyse the relationship between experience and a target 90% completion rate of colonoscopy. The cumulative sum (cusum) score was applied to examine the time trend for the attaining of the target 90% completion rate. This technique described a learning curve which showed, in this instance, that approximately 100 studies were necessary before a 90% completion rate was approached. A further 100 studies were required before this target completion rate was achieved consistently. A trend for continued improvement above the 90% completion rate level was also seen after 200 studies. Polypectomy was completed in 117 of the 123 studies where indicated. Cusum analysis may be a useful method for monitoring the progress of the trainee colonoscopist and the attainment of satisfactory competence. Training requirements, therefore, might better emphasize the attainment of an acceptable completion rate rather than an arbitrary quota per se.
Clinical Competence↗
Dental status and treatment needs of a New Zealand institutionalised elderly population.
A survey of 359 elderly residents of rest homes and geriatric hospitals in the Manawatu and Horowhenua districts showed that approximately two-thirds were aged 80 or over, and 19.5 percent were dentate, with a mean 13.3 teeth per dentate subject. A mean of 4.6 teeth per dentate subject had caries of either the crown or root, or both. Older males had substantially higher extraction requirements than other subjects. The periodontal needs of the sample were generally low and dominated by the need for calculus removal.
Aged↗
The stability of high blood pressure in Dunedin children: an eight year longitudinal study.
Resting blood pressures were recorded for children in the Dunedin Multidisciplinary Health and Development Study at two year intervals five times from age seven to fifteen. Correlations between pairs of readings were modest but significant, and higher for systolic (0.39 to 0.62) than for diastolic blood pressure. However, although children with normal blood pressure were likely to continue to have normal blood pressure, high blood pressures at age seven, nine, eleven and thirteen were not stable--only 28% of those whose systolic blood pressure at age seven was in the highest 5% had two subsequent readings in the highest 5%. On the other hand 56% of those in the highest 20% had two subsequent readings in the highest 20%, and 9% had all subsequent readings in the highest 20%. We do not believe that adult essential hypertensives can be recognised early by annual blood pressure measurement in childhood and the assignation of blood pressure rank according to a set of normal values.
Adolescent↗
Superstructure of the Drosophila ribosomal gene family.
Determining the spatial organization of middle repetitive DNA has proven difficult for several reasons. Repeated arrays are often so large that molecular methods alone cannot resolve their organization, and the lack of phenotypic markers within arrays limits the value of classical genetic analysis. We have characterized the superstructure of one repeated gene family, the ribosomal gene family of Drosophila melanogaster, by a combination of recombinational and molecular analyses of spacer-length variants. The resulting genetic maps demonstrate that some spacer variants are widely dispersed, while others are limited in their distribution. Moreover, exchange among ribosomal DNA (DNA encoding rRNA) arrays was often unequal, leading to a prediction of little or no relationship between physical location in an array and relatedness of gene family members. Extensions of our procedure may be generally useful for mapping the superstructure of repetitive DNA.
Animals↗
The opportunity for natural selection on multigene families.
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Animals↗
Prediction of possibly preventable death: a case-control study of postneonatal mortality in southern New Zealand.
The postneonatal mortality rate in three southern regions of New Zealand was 8.1 per 1000 live births for 1979-1984. The possibly preventable postneonatal mortality rate was 7.1 per 1000 live births and data on 377 possibly preventable deaths and 936 randomly selected controls were used to develop a two-stage risk-scoring system. Logistic regression analysis was undertaken separately on two sub-samples of the total sample. The data were used to evaluate three other previously published scoring systems. The four variables used in our birth score (mother's age, parity, marital status, and birth weight) have all appeared in other scoring systems, and this score could identify a group of infants in southern New Zealand with an estimated 1.7% mortality rate in the first year of life. It is suggested that currently the only valid use of risk-scoring in this region is for the definition of a high-risk population for the purpose of evaluating potential intervention strategies.
Case-Control Studies↗
Growth velocity before sudden infant death.
Weight velocities of 136 infants who died from sudden infant death syndrome (SIDS) were compared with those of 136 controls matched for sex, birth weight, and type of feeding. It was found that the SIDS infants gained weight more slowly overall and that the differences were significantly different for infants who were not breast fed in the last two weeks in which it was possible to estimate their growth velocity. Breast fed infants had more periods of growth below the 25th centile than expected. These differences are unlikely to be useful in the prediction of which babies are likely to die from SIDS as there are frequent episodes of poor growth in infants who do not die.
Birth Weight↗