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Biomedical subjects

R Campbell

Publications and source records attributed to R Campbell.

At least 91 records · Page 5Linked to original sources
PubMed1997

Are faces of different species perceived categorically by human observers?

What are the species boundaries of face processing? Using a face-feature morphing algorithm, image series intermediate between human, monkey (macaque), and bovine faces were constructed. Forced-choice judgement of these images showed sharply bounded categories for upright face images of each species. These predicted the perceptual discrimination boundaries for upright monkey-cow and cow-human images, but not human-monkey images. Species categories were also well-judged for inverted face images, but these did not give sharpened discrimination (categorical perception) at the category boundaries. While categorical species judgements are made reliably, only the distinction between primate faces and cow faces appears to be categorically perceived, and only in upright faces. One inference is that humans may judge monkey faces in terms of human characteristics, albeit distinctive ones.

Adult↗
PubMed1997

Activation of auditory cortex during silent lipreading.

Watching a speaker's lips during face-to-face conversation (lipreading) markedly improves speech perception, particularly in noisy conditions. With functional magnetic resonance imaging it was found that these linguistic visual cues are sufficient to activate auditory cortex in normal hearing individuals in the absence of auditory speech sounds. Two further experiments suggest that these auditory cortical areas are not engaged when an individual is viewing nonlinguistic facial movements but appear to be activated by silent meaningless speechlike movements (pseudospeech). This supports psycholinguistic evidence that seen speech influences the perception of heard speech at a prelexical stage.

Auditory Cortex↗
PubMed1997

Immunoregulatory changes in Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis of unknown etiology, occurring in young children and treated with intravenous gamma globulin (IVIG) to prevent significant cardiac morbidity and mortality. We studied KD patients pre- and post-IVIG therapy and at >40 days posttherapy, additionally comparing them with matched pediatric control patients and parents. Using three-color flow cytometry, we examined immune changes in KD, especially previously unassessed markers of T-lymphocyte activation, memory, and adhesion. The percentage of cells positive for CD19, CD25, CD38, and CD71 was significantly lower during convalescence compared with pre-IVIG (medians: CD19, 18% vs 26%, P = 0.0004; CD25, 6% vs 9% for CD3(+) cells, P = 0.0074; CD38, 78% vs 89% for CD8(+) cells, P = 0.0015; CD71, 1% vs 6% for CD4(+) cells, P = 0.0024). The proportion of CD3(+) cells increased (medians: CD3, 66% vs 45%, P < 0.0001). Values for all parameters varied greatly pre- and post-IVIG, but not in a consistent direction. The sole patient with cardiac abnormalities had the greatest pre-/post-IVIG variability. These changes support the involvement of T-lymphocytes in the acute KD vasculitic process. They also suggest that T-lymphocytes involved in endothelial damage during acute KD may be subsequently removed or eliminated from the peripheral blood.

Antigens, CD↗
PubMed1997

Leukaemia inhibitory factor mRNA is expressed in the brains of patients with subacute sclerosing panencephalitis.

We have examined the in situ transcription of leukaemia inhibitory factor (LIF) in brain tissue from 3 cases of subacute sclerosing panencephalitis (SSPE) and in 2 non-neurological control brains. This has been compared with expression of interleukin 2 (IL-2), interleukin 6 (IL-6) and tumour necrosis factor beta (TNF beta) in the same tissues. All of the cytokines in the study were expressed in cells in the inflammatory infiltrate as well as in glial cells. LIF mRNA was also found to be expressed in neurons, in foci where these cells were also virally infected. No hybridization was found with any of the probes in areas of SSPE brain, which were negative for measles virus RNA or in the non-neurological control cases, although expression was demonstrated in the latter by use of reverse transcription-polymerase chain reaction (RT-PCR). Differentiated, cultured human neuronal cells were also positive, by RT-PCR, for LIF. This is the first demonstration of LIF expression in human brain and the results suggest that this cytokine is up-regulated, in several cell types, including neurons, following virus infection.

Adolescent↗
PubMed1997

Speechreading in the akinetopsic patient, L.M.

Patient L.M. has a well-documented, long-standing and profound deficit in the perception of visual movement, following bilateral lesions of area V5 (visual movement cortex). Speechreading was explored in this patient in order to clarify the extent to which the extraction of dynamic information from facial actions is necessary for speechreading. Since L.M. is able to identify biological motion from point-light displays to whole-body forms and has some limited visual motion capabilities, we expected that some speechreading of faces in action would be possible in this patient. L.M.'s reading of natural speech was severely impaired, despite unimpaired ability to recognize speech-patterns from face photographs and reasonable identification of monosyllables produced in isolation. She was unable to track multisyllabic utterances reliably and was insensitive to vision when incongruent audiovisual speech syllables were shown. Point-light displays of speech were as poorly read as whole face displays. Rate of presentation was critical to her performance. With speech, as with other visual events, including tracking the direction of gaze and of hand-movement sequences, she could report actions that unfolded slowly (approximately one event per 2 s). In line with this, she was poor at reporting whether seen speech rate was normal, fast (double-speed) or slow (half-speed). L.M.'s debility is the converse of that reported for a patient with lesions primarily to V4 (H.J.A.), who is unable to speechread photographs of faces but can speechread moving faces. The visual analysis of both form and motion is required for speechreading; the neural systems that support these analyses are discussed.

Aged↗
PubMed1997

Weight changes and serum sodium concentrations after an ultradistance multisport triathlon.

OBJECTIVE: This study describes the incidence of hyponatremia and the weight changes during an ultradistance multisport triathlon. DESIGN: Descriptive research. SETTING: A 1-day triathlon in which each athlete kayaks 67 km, cycles 148 km, and runs 23.8 km. PARTICIPANTS: Forty-eight athletes competing in the race were studied. INTERVENTIONS: None. MAIN OUTCOME MEASURES: All subjects were weighed before the race and on completion of the race. A blood sample for serum sodium was taken at the finish of the race. RESULTS: The mean weight change over the course of the race was a loss of 2.5 kg (SD +/- 1.7, n = 48), or a mean percentage loss of body weight of 3.1% (SD +/- 2.07). This was highly statistically significant (p < 0.0001) using the Student paired t test. No athletes gained weight, and six athletes maintained their same weight. Only one athlete was hyponatremic (Na = 134 mEq/L). This athlete maintained his weight over the course of the race and he did not seek medical attention. The mean serum sodium concentration at the end of the race was 139.3 mEq/L (SD = 2.28, n = 47). There was a significant correlation (r = 0.30, p = 0.04) between sodium levels and weight change during the race: the greater the weight loss, the higher the serum sodium concentration. There was no significant correlation between the degree of weight loss and athletes' finishing times (r = 0.11, p = 0.45). CONCLUSIONS: Symptomatic hyponatremia did not occur in the 1996 Coast to Coast multisport triathlon, although one athlete had borderline hyponatremia. Athletes lose significant amounts of weight over the course of this multisport event, but nevertheless manage to complete the race.

Adult↗
PubMed1997

The medical therapy of cardioinhibitory syncope in pediatric patients.

A small percentage of pediatric patients with neurally mediated syncope will have an asystolic response during upright tilt table testing. The purpose of this study is to evaluate the incidence of asystole during tilt table testing, and to assess the outcome of medical management of such patients. Of 398 patients undergoing evaluation for recurrent syncope between January 1989 and 1994, 18 (4.5%) experienced asystole lasting > or = 5 seconds during baseline tilt test. Patients had experienced a mean of four episodes of syncope, with a mean age at the time of tilt test of 11.1 +/- 4.0 years. The median duration of asystole was 10 seconds (range 5-40 s). Treatment was individualized to increased fluids and salt intake (3 patients), metoprolol (8 patients), pseudoephedrine (4 patients), disopyramide (1 patient), or combination therapy with fludrohydrocortisone (2 patients). During a median duration of follow-up of 31 months, no additional syncope was experienced by 78% of patients. Recurrent syncope in 4 patients was associated with either noncompliance or discontinuation of therapy in 3 patients; in 1 patient, increasing the dose of metoprolol was effective in preventing recurrences. We conclude that young patients with recurrent syncope and asystole during tilt test may be safely and effectively managed with pharmacological therapy, without resorting to pacemaker implantation.

Adrenergic Agonists↗
PubMed1997

The impact of legislatively imposed practice guidelines on cesarean section rates: the Florida experience.

Florida legislation implemented in the fall of 1992, unique in the nation, mandated that practice guidelines regarding cesarean section deliveries be disseminated to obstetric physicians. The law also required that peer review boards at hospitals be established to review cesarean deliveries and that the exact dates of implementation of the guidelines be reported to a state agency. To determine the impact of the legislation, we conducted a retrospective analysis of 366,246 total live births occurring in Florida hospitals during 1992 and 1993, before and after formal hospital certification of the implementation of the guidelines. Changes in primary and repeat cesarean rates were analyzed for 108 independent groups of births, controlling for the mother's age, race, payment source, and the timing of the implementation of the guidelines at hospitals. The guideline certification program did not accelerate the consistent but gradual downward trend in cesarean births which had already been evident in the three prior years. The data do suggest that the guideline program may have affected repeat cesareans more than primary cesareans, especially in the first quarter of 1993, immediately after the hospital certification period. Reductions in repeat cesareans involved both Medicaid and commercially insured births, whereas reductions in primary cesareans were found almost exclusively within commercially insured mothers, where the existing rates are highest. Although births with a prior cesarean represent only 12.5% of all births, significant decreases in repeat cesareans were found in groups representing 72.6% of this population. By comparison, significant decreases in primary cesareans were found in groups representing only 36.5% of the births without a prior cesarean. The date of guideline implementation reported by hospitals was not related to any systematic change in observed cesarean section rates. We concluded that the mere dissemination of practice guidelines by a state agency may not achieve either the magnitude or the specificity of the results desired without an explicit and thorough guideline implementation program. Blunt legislative mandates may be ineffective when multiple initiatives are already achieving desired outcomes.

Adolescent↗
PubMed1997

Emergency medical services for rape victims: detecting the cracks in service delivery.

Rape victims have many emergency medical needs, yet there has been very little research examining whether victims are receiving desired assistance. In this study, 147 rape victim advocates were interviewed about their most recent case in which a victim has sought treatment in an emergency room (ER). The results of this study indicated that there is some inconsistency in which services victims receive and that many women did not obtain the resources they wanted. Some forms of assistance were not provided to victims due to lack of resources in their communities (e.g., follow-up medical care). Other services were not offered due to problems in the implementation of available services (e.g., the morning-after pill [ethinyl estradiol-norgestrel] to prevent pregnancy). This research also examined how characteristics of the hospitals, the assaults themselves, and the victims impacted whether women would receive desired help. These findings indicated that women who were treated in hospitals affiliated with the Catholic church; those who were raped by their friends, dating partners, or husbands; those who experienced multiple forms of forced penetration (vaginal rape and anal rape, oral rape, or rape by an object); women of Color; and victims who did not present a sympathetic demeanor in the ER were less likely to receive several forms of assistance, such as treatment of physical injuries, arranging follow-up medical care, information and treatment for sexually transmitted diseases, information on the risk of pregnancy, the morning-after pill, and information on the physical and psychological health effects of sexual assault. Victims who were taken to hospitals that had coordinated response teams (e.g., Sexual Assault Response Teams) to work with survivors were more likely to receive some forms of treatment (e.g., information on the physical and psychological health effects of sexual assault). Implications for future research and policy initiatives in women's health are discussed.

Adolescent↗
PubMed1996

HLA-DR4-IE chimeric class II transgenic, murine class II-deficient mice are susceptible to experimental allergic encephalomyelitis.

To investigate the development of HLA-DR-associated autoimmune diseases, we generated transgenic (Tg) mice with HLA-DRA-IE alpha and HLA-DRB1*0401-IE beta chimeric genes. The transgene-encoded proteins consisted of antigen-binding domains from HLA-DRA and HLA-DRB1*0401 molecules and the remaining domains from the IE(d)-alpha and IE(d)-beta chains. The chimeric molecules showed the same antigen-binding specificity as HLA-DRB1*0401 molecules, and were functional in presenting antigens to T cells. The Tg mice were backcrossed to MHC class II-deficient (IA beta-, IE alpha-) mice to eliminate any effect of endogenous MHC class II genes on the development of autoimmune diseases. As expected, IA alpha beta or IE alpha beta molecules were not expressed in Tg mice. Moreover, cell-surface expression of endogenous IE beta associated with HLA-DRA-IE alpha was not detectable in several Tg mouse lines by flow cytometric analysis. The HLA-DRA-IE alpha/HLA-DRB1*0401-IE beta molecules rescued the development of CD4+ T cells in MHC class II-deficient mice, but T cells expressing V beta 5, V beta 11, and V beta 12 were specifically deleted. Tg mice were immunized with peptides, myelin basic protein (MBP) 87-106 and proteolipid protein (PLP) 175-192, that are considered to be immunodominant epitopes in HLA-DR4 individuals. PLP175-192 provoked a strong proliferative response of lymph node T cells from Tg mice, and caused inflammatory lesions in white matter of the CNS and symptoms of experimental allergic encephalomyelitis (EAE). Immunization with MBP87-106 elicited a very weak proliferative T cell response and caused mild EAE. Non-Tg mice immunized with either PLP175-192 or MBP87-106 did not develop EAE. These results demonstrated that a human MHC class II binding site alone can confer susceptibility to an experimentally induced murine autoimmune disease.

Amino Acid Sequence↗
PubMed1996

Optic aphasia: a case with spared action naming and associated disorders.

AG, a pure case of optic anomia (object naming impaired; action naming good) is described. We consider the fit of experimental data from AG to different theoretical accounts of optic aphasia. Overall, we find no evidence for impairments intrinsic to semantic representations, but we note a number of problems that we interpret as indicating a slight, and specific, weakness in semantic access from vision. We also note a mild problem in generating names to a cue (verbal fluency). The main aim of the report was to provide a full description of tests of visual, semantic, and speech output skills in this patient in relation to the processing of visually presented objects and scenes, within a sequential information processing account which enables some theoretical implications to be drawn, albeit not conclusively.

Adult↗
PubMed1996

The lateralization of lip-reading: a second look.

Photographs of unfamiliar speaking faces were matched by normal right-handed subjects on the basis of perceived mouth-shape (i.e. visible speech sound) across different face-views. A clear left-hemisphere (RVF) processing advantage emerged, which was absent when the task was that of identity matching. In contrast to earlier proposals, the extraction of lip-shape from face photographs may be better managed by left-hemisphere- than right-hemisphere mechanisms even at its initial stages. This may contribute to the observed patterns of dissociations in speech-reading and in audiovisual speech-processing in neurological patients.

Adult↗
PubMed1996

The effect of a 4-mg preoperative intravenous dose of ondansetron in preventing nausea and vomiting after maxillofacial surgery.

PURPOSE: The efficacy of a preoperative 4-mg dose of ondansetron given intravenously in preventing postoperative nausea and vomiting after maxillofacial surgery was evaluated in a double-blind randomized study. PATIENTS AND METHODS: Sixteen patients had intravenous ondansetron, and an equal number had normal saline as a placebo immediately before induction of anesthesia. After intubation, a nasogastric tube was inserted, and general anaesthesia was induced with thiopentone, suxamethonium, fentanyl, nitrous oxide, enflurane, and vecuronium. Anesthesia lasted more than 1 hour in all patients. Postoperatively, episodes of vomiting were recorded, and nausea was assessed on a visual analog scale at 1, 4, and 24 hours from the time of awakening. RESULTS: Eight patients in the ondansetron group, compared with six in the placebo group, had nausea, and six in the ondansetron group and three in the placebo group vomited. Of the six patients who vomited in the ondansetron group, five vomited more than 8 hours from the injection of ondansetron. No significant adverse effects could be directly attributable to ondansetron. CONCLUSION: Four milligrams ondansetron given intravenously preoperatively was ineffective in controlling postoperative nausea and vomiting after maxillofacial surgery. Possibly, a larger dose or a second dose given 8 hours after the first dose may be effective.

Adult↗
PubMed1996

Dissociating face processing skills: decision about lip-read speech, expression, and identity.

The separability of different subcomponents of face processing has been regularly affirmed, but not always so clearly demonstrated. In particular, the ability to extract speech from faces (lip-reading) has been shown to dissociate doubly from face identification in neurological but not in other populations. In this series of experiments with undergraduates, the classification of speech sound (lip-reading) from personally familiar and unfamiliar face photographs was explored using speeded manual responses. The independence of lip-reading from identity-based processing was confirmed. Furthermore, the established pattern of independence of expression-matching from, and dependence of identity-matching on, face familiarity was extended to personally familiar faces and "difficult"-emotion decisions. The implications of these findings are discussed.

Adolescent↗