Biomedical subjects
Publications and source records attributed to L Richards.
Cancrum oris (noma) has been most commonly described in malnourished debilitated children with poor oral hygiene following systemic childhood infections such as measles, pertussis or scarlet fever. We describe a patient who developed this condition during a period of profound neutropenia following cytotoxic chemotherapy for acute lymphoblastic leukaemia.
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Because language and praxis each require the activation and selection of knowledge structures in long-term memory (MacKay, 1985, 1987), it is reasonable to consider whether hemisphere asymmetries for such processes span both domains. Language and skilled movement are thought to be strongly lateralized to the left hemisphere in most individuals. Yet, although recent evidence suggests that the right hemisphere also contributes to language use in context, few similar arguments have been made for the right hemisphere's involvement in motor planning. In this paper, we review some of the evidence for a right hemisphere role in language and action processing and propose that within each domain the right hemisphere activates a range of relevant knowledge structures without selection.
The purpose of this study was to determine whether rugae patterns change with age and to compare the number and pattern of rugae in Australian Aborigines with those of Caucasians. For the longitudinal part of the study, serial dental casts of ten Aborigines, from 6 to 20 years of age, were examined and rugae patterns were recorded. To enable comparisons to be made between different ethnic groups an additional 100 dental casts of Australian Aborigines and 200 casts of caucasians, ranging in age from 13 to 17 years, were examined. Characteristics observed were number, length, shape, direction and unification of rugae. The length of rugae increased significantly with age but the total number of rugae remained constant. Thirty-two per cent of rugae showed changes in shape, while 28 per cent displayed a change in orientation. In contrast to studies suggesting that rugae move forward with age, the majority of Aboriginal rugae that changed direction moved posteriorly. Changes in rugae patterns have been assumed to result from palatal growth but alterations in pattern were observed in the Aboriginal sample even after palatal growth had ceased. The mean number of primary rugae in Aborigines was higher than in Caucasians, although more primary rugae in Caucasians exceeded 10 mm in length than in Aborigines. The most common shapes in both ethnic groups were wavy and curved forms, whereas straight and circular types were least common. There was a statistically significant association between rugae forms and ethnicity, straight forms being more common in Caucasians whereas wavy forms were more common Aborigines.
BACKGROUND: Depression has a marked negative impact on geriatric patient mortality and morbidity. The risk factors and exact reasons for these effects are not well understood. METHOD: Seeking to better define the factors, we retrospectively analyzed the effects of gender and age at onset of affective disorder in a naturalistic study of 192 geriatric patients consecutively admitted to a large midwestern tertiary care center between 1980 and 1987 for the treatment of unipolar depression. RESULTS: After controlling for age at index admission, patients with an onset of depression before age 40 suffered significantly (p < .05) less mortality in follow-up than those with onset after age 40. When effects of gender are examined, the effects of age at onset are most profound in women, with a threefold increase in the rate of death in the cohort with age at onset of depression after 70 years when compared to those with onset before age 40. CONCLUSION: These results and those of others suggest that depressed elderly women with no previous history of affective disorder are at a markedly increased risk compared with elderly women with a history of affective illness for morbidity and mortality and that a significant proportion of elderly depressed patients are admitted to a psychiatric hospital for a depression that is secondary to serious medical illness.
Nocardiosis is an uncommon disease which occurs most often in patients with impaired cellular immunity, yet is rarely reported in patients with Human Immunodeficiency Virus Disease. We present the first case of Nocardiosis seen at the University Hospital of the West Indies, occurring in a well-controlled diabetic with Human Immunodeficiency Virus Disease.
This study investigated the depth of associative activation in the cerebral hemispheres. Semantic priming was assessed for direct (WATER-DRINK) and indirect (mediated: SOAP-DRINK) associates presented to the left and right visual fields across stimulus-onset-asychronies (SOAs) of 50, 250 and 750 msec. Priming for both the direct and indirect associates was found in both visual fields at all SOAs. Our results imply that activation via associated relations in semantic memory is early and extensive in both hemispheres. We relate our findings to the previous suggestion [5, 9, 14] that meaning activation is more narrow in the left hemisphere (LH) than in the right hemisphere (RH).
Horizontal and vertical stings were presented in a "crosswords" format within left or right visual fields. Distractor strings were varied to examine the extent to which prelexical, orthographic-phonological, and semantic codes are activated for words not focally attended. The results supported 2 predictions of the pathway strength model of attentional modulation (JD Cohen, K Dunbar & JL McClelland, 1990). First, distractor influences were greater when participants attended to the weaker (ie, vertical) item and ignored the stronger (ie, horizontal) string, than vice versa. Second, distractors similar to the target facilitated, whereas dissimilar distractors interfered with, pronunciation responses. It is concluded that spatial attention can modulate word recognition processes, and that some interesting questions emerge when one abandons the assumptions of serial, noninteractive word recognition processes.
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The frequency of agenesis of maxillary lateral incisors (I2) in a sample of South Australian twins was determined, and associations with gender, zygosity, birthweight and dental crown size were investigated. Ten of the 446 twins examined (2.24 per cent) displayed agenesis of one or both I2, a similar frequency to that reported for Australian singletons. Seven of the ten affected individuals were monozygous female twins, including two pairs, while the three affected dizygous twins were each from different male twin pairs. Five pairs of monozygous twins were identified who displayed varying expressions of normal, small, peg-shaped or missing I2. These twin pairs displayed disparate birthweights suggesting they may have been mono-chorionic. These findings are consistent with a multifactorial threshold model linking size and number of I2 with developmental influences modifying phenotypic expression in those monozygous twins whose genetic predisposition places them near to the threshold for agenesis.
BACKGROUND: Recent reports have called into question the safety and effectiveness of electroconvulsive therapy (ECT). METHOD: To investigate these claims, the effects of ECT on clinical outcomes were examined as part of a retrospective, naturalistic study of 192 geriatric patients consecutively admitted between 1980 and 1987 to a large midwestern tertiary care center for the treatment of depression. Data were analyzed by a variety of parametric and nonparametric methods including ANOVA and survival analysis. RESULTS: Patients who received ECT (N = 108) were more likely to exhibit psychomotor retardation and to have had prior courses of ECT than those who did not receive ECT (N = 84). Furthermore, despite the absence of differences in the overall rate or severity of medical comorbidity, patients receiving ECT were more likely to be alive at follow-up and to demonstrate greater clinical improvement than those treated only with pharmacotherapy. CONCLUSION: These results confirm previous studies demonstrating the superior efficacy of ECT as compared with conventional pharmacotherapy treatment in patients hospitalized with depression and document its safety in long-term follow-up.
A relatively enduring and counterintuitive antimanic response to dextroamphetamine in a brain-injured adolescent who had failed trials involving divalproex, lithium, haloperidol, and carbamazepine is described. This finding combined with data from previous reports of antimanic effects of test doses of stimulants imply that such a pharmacological probe may prove relevant for the prediction of treatment response of mania to dextroamphetamine and perhaps for subclassification of bipolar disorder.
Leukemia inhibitory factor (LIF) has several characteristics of a neurotrophic factor for sensory neurons. Here we have investigated whether LIF also supports the survival of axotomised sensory neurons in vivo. Newborn rat pups received a unilateral sciatic nerve transection and the injury site was treated with gelfoam soaked in phosphate buffered saline (PBS), nerve growth factor (NGF), or LIF. Neuronal nucleoli in the L5 dorsal root ganglia were counted, appropriate corrections applied, and the resultant neuronal loss expressed as a percentage of the contralateral intact side. In animals where LIF was administered neuronal loss was significantly reduced: 2 days after LIF treatment neuronal loss was 19.5% compared to 43% in PBS-treated animals; 3 days after LIF treatment neuronal loss was 20.4% compared to 40.2% in PBS-treated animals; however, 7 days after LIF treatment there was no significant reduction in the number of neurons lost. The degree of rescue of sensory neurons in vivo by LIF was found to be similar to NGF, which was not surprising as both factors supported the survival of a similar population of sensory neurons in vitro. Rescue was not observed when LIF-containing gelfoam was placed away from the axotomised nerve, suggesting that LIF's action may be associated with its retrograde transport or direct signalling at the site of nerve injury.
Previous studies in the United States have suggested that submissive women may be more vulnerable to criminal victimization because they present certain cues of vulnerability. Richards, Rollerson, and Phillips (1991) observed that submissive women exhibited more controlled body movements and more body-concealing clothing than did dominant women. Our purpose here was to determine whether such variability might be due to differences in body boundary definition. The results revealed no significant difference in the body boundary indicators of dominant and submissive subjects but did suggest that highly feminine women are more likely to have weak body boundaries than are more androgynous women.
This paper identifies criteria seen as essential to feminist research. In light of these criteria, issues which have arisen during our current research on women and their experiences of midlife and menopause are discussed. Issues considered include the researchers' responsibilities to participants when exploring sensitive and highly personal issues relating to participants' life experiences, and less clear cut issues such as knowledge construction, power and control. In relation to the latter the balance of power in the research-participant relationship, and the role and responsibilities of the researcher in knowledge construction, are explored. Foucault's notions of knowledge construction and power and control and the feminist researcher's position, are considered in terms of rigour in feminist research and dissemination of research reports. Issues which are seen as problematic and worthy of further debate are: the relations between interviewer and interviewee; the intellectual (the researcher) as the bearer of universal values and as truth teller; and the level of critical activism possible in research studies of this nature.
In 1990 childhood diarrhoea and acute respiratory infections together accounted for 7.5 million deaths of children younger than five years of age in developing countries. To decrease mortality and treatment costs associated with these illnesses, the World Health Organization has developed standard diagnostic and treatment procedures for health staff, and is working on strategies for disease prevention. Immunisation against measles, adequate nutrition, including exclusive breastfeeding for the first four to six months, and improved water supplies and sanitation are the most important preventive measures. The 1990 World Summit for Children has set goals of a 50% reduction in childhood mortality from diarrhoea and a 33% reduction in mortality from acute respiratory diseases by the year 2000. These goals can be achieved by political commitment and a major investment of resources, but sustained support for these efforts from the medical professions is crucial.
Trypan blue exclusion was used to estimate the viability of human polymorphonuclear leukocytes (PMNL) in the presence of Mycoplasma felis and two strains of M. fermentans (PG18 and incognitus). The competence of PMNL to mount a respiratory burst when challenged with the mycoplasmas was also monitored by luminol-dependent chemiluminescence (CL). Both un-opsonised and non-immune human serum opsonised M. felis cells had little effect on PMNL viability. In contrast, PMNL viability was reduced markedly by un-opsonised cells of M. fermentans strain incognitus and, to a lesser extent, strain PG18, and opsonisation of these mycoplasmas further enhanced killing. Death of PMNL in the presence of M. fermentans was not associated with the autonomous production of active oxygen species during the respiratory burst as M. felis induced a high CL response from PMNL, whereas that induced by M. fermentans strain incognitus was significantly lower. M. fermentans may invade mammalian cells and it is suggested that the mechanism of PMNL death could be related to the ability of M. fermentans to penetrate host cell membranes.
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