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Biomedical subjects

A Craig

Publications and source records attributed to A Craig.

At least 55 records · Page 3Linked to original sources
PubMed1999

Improving the long-term adjustment of spinal cord injured persons.

STUDY DESIGN: The study involved the long-term assessment of persons with spinal cord injury (SCI) who previously participated in a nonrandomized longitudinal controlled trial. OBJECTIVES: The objective was to report on the effectiveness of early psychological intervention in improving some aspects of adjustment to SCI 2 years post injury. SETTING: The study was conducted in Sydney, Australia. METHODS: Twenty-eight SCI persons who had participated in group Cognitive Behaviour Therapy (CBT) during hospital rehabilitation were assessed for drug usage, hospital readmissions, relationships, perceived adjustment and social discrimination 2 years after treatment. The intervention group's responses on the measures were compared with a control group of 31 SCI persons who only received traditional rehabilitation services during their hospitalization. RESULTS: Subjects in the treatment group experienced less hospital re-admissions, used less drugs and reported higher levels of adjustment compared to the control group. Relationships were stable for both groups and there were no suicides in either group up to 2 years. There were no differences in perceived social discrimination between the two groups. CONCLUSION: The study suggests the long-term adjustment for SCI persons is encouraging for the majority. However, the provision of group CBT for SCI persons appears to improve significantly some aspects of adjustment to the injury in the long-term.

Adolescent↗
PubMed1998

Two- to six-year controlled-trial stuttering outcomes for children and adolescents.

This research is a long-term follow-up of a previously published, controlled trial on the effectiveness of 3 stuttering treatments (intensive smooth speech, parent-home smooth speech, and intensive electromyography feedback) for children and adolescents, aged 11 to 18 years, who stutter. The previous controlled trial showed all 3 treatments to be effective compared to nontreatment after 12 months. This paper reports on the treatment effectiveness after an average of 4 years post-treatment. Results demonstrate that treatment gains were maintained in the long term, with rates of stuttering similar to the 1-year postoutcomes. There were no significant differences among the 3 treatments in long-term effectiveness. This controlled study substantiates the claim that the treatments investigated will more than likely have substantial long-term benefits for the fluency and personality of children and adolescents who stutter.

Adolescent↗
PubMed1998

Three methods compared for detecting the onset of alpha wave synchronization following eye closure.

Recent work indicates that the variation in the occipital alpha wave component of the EEG spectrum, controlled through eye closure, can be used by an untrained person to effect reliable activation of electrical devices. Here we describe and compare three real-time strategies, based on analogue and digital signal processing methods, of detecting the onset of alpha wave synchronization during eye closure. The goal of this work is to establish a method which satisfies the condition of rapid detection of alpha wave enhancement, thereby allowing for the efficient activation of devices, while simultaneously registering few or no false positives due to the natural variation in the alpha signal with eyes open. This work, based on measurements on 15 subjects in the age range 12 to 40 years, indicates that renal-time analysis of the EEG power spectrum provides for rapid detection of the onset of alpha wave synchronization while maintaining low counts of false positives.

Alpha Rhythm↗
PubMed1998

The effectiveness of group psychological intervention in enhancing perceptions of control following spinal cord injury.

OBJECTIVE: This research investigated the effects of a structured psychological intervention, delivered during hospital rehabilitation, on the perceptions of control in people with spinal cord injury (SCI). METHOD: A longitudinal study was designed to assess perceptions of control (using an objective measure of locus of control) in SCI persons who participated in specialised group cognitive-behavioural therapy (CBT) during hospital rehabilitation. The treatment SCI group's responses on locus of control were compared with a control group of SCI persons who only received traditional rehabilitation services during their hospitalisation. RESULTS AND CONCLUSIONS: Mean locus of control scores were not high (i.e. external) for both groups and there were no overall group differences on locus of control responses across time in comparison to the control group. However, subjects in both groups who initially perceived life as externally controlled were extracted to form subgroups. The members of the subgroup who received CBT were significantly more likely to feel in control of themselves 2 years post injury compared to similar persons in the control group. Furthermore, an external locus of control was significantly but mildly associated with depressive mood 2 years after the injury. This research suggests that the provision of a structured psychological program in the rehabilitation stage will be beneficial for many SCI persons who feel that they have little control over their lives.

Adolescent↗
PubMed1997

Intercellular adhesion molecule-1 and CD36 synergize to mediate adherence of Plasmodium falciparum-infected erythrocytes to cultured human microvascular endothelial cells.

We have compared the adhesion of Plasmodium falciparum-infected erythrocytes to human dermal microvascular endothelial cells (HDMEC) and human umbilical vein endothelial cells (HUVEC) and have assessed the relative roles of the receptors CD36 and intercellular adhesion molecule-1 (ICAM-1). HUVEC (a cell line that expresses high levels of ICAM-1 but no CD36) mediate low levels of adhesion, whereas HDMEC (which constitutively express CD36) mediate high levels of adhesion even before ICAM-1 induction ICAM-1 expression leads to yet greater levels of adhesion, which are inhibited both by anti-ICAM-1 and CD36 mAbs, despite no increase in the expression of CD36. The results indicate the presence of a substantial population of infected cells that require the presence of both receptors to establish adhesion. Synergy between these receptors could be demonstrated using a number of parasite lines, but it could not be predicted from the binding of these same parasite lines to purified ICAM-1 and CD36. This phenomenon could not be reproduced using either purified receptors presented on plastic, or formalin-fixed HDMEC, suggesting that receptor mobility is important. This is the first study to demonstrate receptor synergy in malaria cytoadherence to human endothelial cells, a phenomenon necessary for parasite survival and associated with disease severity.

Animals↗
PubMed1997

EEG-based system for rapid on-off switching without prior learning.

Details are reported of an EEG-based system that permits a person rapidly and reliably to switch on and off electrical devices without prior learning. The system detects and utilises increases in the amplitude of the alpha component of the EEG spectrum that occur when people close their eyes for more than 1 s. In addition to conventional signal-processing elements, the system incorporates a module for suppressing switching at the output of the system when predetermined noise threshold levels (such as those due to sources of EMG) are exceeded. This work indicates that a majority, perhaps in excess of 90%, of the adult population can demonstrate the control necessary to operate an electrical device or appliance using this system. It is indicated that multi-level switching and quasi-continuous control options are feasible with further development of the system. This work has implications for the design of a system that could be used, for example, to assist the infirm or severely physically disabled to effect greater control over their environment.

Adult↗
PubMed1997

Growth hormone secretion and circulating insulin-like growth factor-I (IGF-I) and IGF binding protein-3 concentrations in children with sickle cell disease.

Impaired growth involving both height and weight accompanying sickle cell disease (SCD) poses diagnostic and therapeutic problems. We undertook this study to test the hypothesis that this impaired growth is associated with abnormalities of the growth hormone (GH)/insulin-like growth factor-I (IGF-I)/IGF binding protein-3 (IGFBP-3) axis in 21 children with SCD and that SCD is associated with GH resistance. Nine of 21 children with SCD had a defective GH response to both clonidine and glucagon provocation (peak < 10 micrograms/L); these children differed from the 12 others in having slower linear growth velocity (GV and GVSDS), lower circulating concentrations of IGF-I and IGFBP-3, and either partial or complete empty sellae in computed tomographic scans of the hypothalamic-pituitary area. In this group of patients with SCD, it appears that defective GH secretion and consequent low IGF-I production are the major etiological factors causing the slow growth. The two groups with SCD did not differ significantly in dietary intake, body mass index (BMI), midarm circumferences, skinfold thickness, serum albumin concentration, or intestinal absorption of D-xylose. A single injection of GH produced a smaller increase in circulating IGF-I in children with SCD with or without defective GH secretion versus 10 age-matched children with idiopathic short stature (ISS) and 11 children with isolated GH deficiency (GHD), suggesting partial GH resistance in the SCD group. The presence of defective GH secretion, decreased IGF-I synthesis, and partial resistance to GH in short children with SCD suggests that treatment with IGF-I may be superior to GH therapy for improving growth.

Adrenergic alpha-Agonists↗
PubMed1997

Placebo-controlled biofeedback blood pressure effect in hypertensive humans.

The role of biofeedback in blood pressure control remains ill-defined because of nonspecific (placebo) effects, small study numbers, and the technical limitations of continuous pressure feedback. Clarification of its potential is awaited by those seeking a nonpharmacological approach to blood pressure control. This study examines the capability for systolic pressure lowering of 5 mm Hg or more using continuous pressure feedback in a statistical sample of untreated, well-characterized, mildly hypertensive individuals. Subjects were randomized in a double-blind study to active or placebo biofeedback. Placebo consisted of a modified contingency approach, using a partial disguise based on a digital high pass filter with 15 elements. Blood pressure-lowering capability was assessed during two laboratory sessions. Continuous visual feedback resulted in 11 of 28 subjects on active treatment and 12 of 28 on placebo treatment lowering their systolic pressure by 5 mm Hg or more (11 +/- 5.6 and 12 +/- 8.4 mm Hg, respectively; P = NS). Prestudy pressure was well-matched (153 +/- 9/97 +/- 4 and 154 +/- 8/98 +/- 4 mm Hg, respectively). An initial small difference in diurnal profile did not change. These findings indicate that among mildly hypertensive individuals, almost half can lower systolic pressure at will for short periods. This capability is independent of the real or placebo nature of the feedback signal. We conclude that there is no specific short-term biofeedback pressure-lowering capability in hypertensive individuals. Further exploration is needed to determine whether specific components of the placebo effect can be delineated, whether personality characteristics influence the response, and whether further biofeedback training can alter the outcome.

Adult↗
PubMed1997

Limited spatial clustering of individual Plasmodium falciparum alleles in field isolates from coastal Kenya.

We describe Plasmodium falciparum genetic diversity in coastal Kenya, typing S-antigen and the merozoite surface proteins 1 and 2 (MSP-1 and MSP-2) in field isolates by the polymerase chain reaction (PCR). Malaria in coastal Kenya is characterized by low seasonal transmission, and a relatively high incidence of severe disease, which tends to occur in time-space clusters. We chose the highly polymorphic S-antigen as a marker for localized parasite diversity because it has been shown to vary in serotype prevalence in time and space. A total of 261 children (up to nine years of age) in two neighboring locations with different transmission rates were sampled for blood-stage parasites in cross-sectional surveys before and after the main transmission period in 1991, and also in a concomitant one-year longitudinal survey tracing clinical infections. Six major sequence types of S-antigen were identified, which were subdivided into 70 alleles; however, only 50% of isolates were typeable. The S-antigen sequence types varied qualitatively between locations, over time, and between asymptomatic and clinical disease infections, but not between different age groups. The MSP-1 and MSP-2 sequence type prevalences, in contrast, did not differ in any of these comparisons. We describe the use of the Mantel test for assessing clustering of individual parasite alleles at the household level, and demonstrate low-level clustering of MSP-1 and MSP-2 alleles and S-antigen sequence types, at the end of a long period of low transmission.

Age Factors↗
PubMed1997

Receptor-specific adhesion and clinical disease in Plasmodium falciparum.

One important factor in the virulence of infections with Plasmodium falciparum is the adherence of infected erythrocytes to small vessel endothelium. In infections that lead to serious, life-threatening disease accumulation of large numbers of infected cells in particular organs is thought to lead to organ dysfunction or failure. This is of particular relevance when the affected organ is the brain, leading to the development of cerebral malaria. Many different endothelial receptors for infected red blood cells have been identified. Some receptors such as CD36 and thrombospondin are used by all parasite isolates, whereas others such as intercellular adhesion molecule-1 (ICAM-1) or vascular cell adhesion molecule (VCAM) are used by a subset of field and laboratory isolates. While it has been speculated that the ability to bind or affinity of binding to a particular endothelial receptor may be related to the pattern of disease, only studies with limited numbers of patients have been carried out to date and these have been in general inconclusive. Here we have taken parasite isolates from 150 patients with defined clinical syndromes as well as isolates from 50 healthy but parasitized community controls and quantitatively assessed their binding to purified endothelial receptors in vitro. Our results show that disregarding the level of adhesion, all parasites bind to CD36, most bind to ICAM-1, few bind to VCAM, and almost none bind to E-selectin. In assessing the degree of binding we show that 1) binding to all receptors was reduced in parasites taken from severely anemic patients; 2) binding to CD36 is identical in parasites from cerebral malaria patients and community controls but slightly elevated in parasites from nonsevere cases; and 3) binding to ICAM-1 is highest in cerebral malaria patients. Because rosette formation by uninfected cells has also been a phenotype associated with disease severity and one that may interfere in vitro with receptor binding, we also assessed rosette formation in all isolates. In this study the highest level of rosette-forming parasites was found in the anemic group and not the cerebral malaria group. Stratifying the data for the frequency of rosette formation showed that the above results were not significantly altered by this phenomenon. Our data are not consistent with a role for binding to CD36 in the development of severe disease but show an association between the degree of binding to ICAM-1 and clinical illness in nonanemic patients.

Anemia↗
PubMed1996

Alzheimer disease and frontotemporal dementias. Behavioral distinctions.

BACKGROUND: Frontotemporal dementia (FTD) is a syndrome produced by lobar degeneration of the temporal and/or frontal lobes. OBJECTIVES: To quantify the behavioral disturbances of FTD and compare them with behavioral changes observed in Alzheimer disease (AD). DESIGN: Cross-sectional comparison of 2 groups defined by research diagnostic criteria and single photon emission computed tomography. Behaviors were assessed using a standardized rating scale-Neuropsychiatric Inventory. Groups were matched for dementia severity. SETTING: Patients were seen at 2 university-based outpatient dementia clinics and a Veterans Affairs medical center. PARTICIPANTS: Twenty-two patients with FTD and 30 patients with AD. RESULTS: Patients with FTD had significantly greater total Neuropsychiatric Inventory scores than patients with AD and exhibited more apathy, disinhibition, euphoria, and aberrant motor behavior. The Neuropsychiatric Inventory accurately assigned 77% of patients with FTD and 77% of patients with AD to the correct diagnostic group using disinhibition, apathy, and depression. Patients with FTD had higher levels of disinhibition and apathy with relatively lower levels of depression compared with patients with AD. CONCLUSIONS: The Neuropsychiatric Inventory provides a behavioral profile that differentiates patients with FTD from patients with AD. Patients with FTD are more behaviorally disturbed but are often less depressed than patients with AD relative to their level of apathy.

Aged↗
PubMed1996

A controlled clinical trial for stuttering in persons aged 9 to 14 years.

This paper presents the results of a controlled trial of child stuttering treatment. The aim of the study was, first, to compare the effectiveness of three viable treatments, and, second, to compare these three treatments to a no-treatment control composed of children who stuttered of a similar age and sex ratio who were on treatment waiting lists. The three treatments investigated included intensive smooth speech, intensive electromyography feedback, and home-based smooth speech. The children/adolescents were assessed across three speaking contexts on measures of percentage syllables stuttered (% SS) and syllables spoken per minute (SPM) and outcomes were assessed 12 months later. Repeated measures analyses of variance demonstrated significant differences between the control group and all three treatment groups across time on conversations in the clinic, on the telephone, and at home (although home measures were not taken for the intensive smooth speech group). Although the controls' stuttering did not change across time, the treatment groups' stuttering was decreased to very low levels posttreatment (less than 1% syllables stuttered on average), with mean improvement in stuttering frequency of at least 85% to 90% across all assessment contexts. Stuttering did not increase significantly up to 3 months and one year posttreatment in the experimental groups, although levels did rise across time (less than 3% syllables stuttered on average). Speech naturalness results showed increasing naturalness across time as rated by the clinician and parent. This was not the case for the controls. The children were also less anxious across time following treatment. The results suggest that all three treatments for children aged 9-14 who stutter were very successful in the long term for over 70% of the group, though the EMG feedback and home-based treatments were superior when percentages falling below a cutoff point (2%SS) were used to discriminate between groups. Implications for child/adolescent treatment in the community are discussed. Long-term outcomes will be assessed up to 5 years after the treatment.

Adolescent↗
PubMed1996

Nucleotide sequence, insertional mutagenesis, and transcriptional mapping of a conserved region of the baculovirus Autographa californica nuclear polyhedrosis virus (map unit 64.8-66.9).

The nucleotide sequence of a 2773-bp region of the Autographa californica nuclear polyhedrosis virus HR3 variant (AcMNPV) (map unit 64.4-68.2) has been determined. This region lies between the previously analyzed p6.9 and p80 genes. Three open reading frames were contained within this region, potentially coding for proteins of 45, 40, and 12 kDa. The 5' ends of transcripts capable of coding for the 45- and 12-kDa proteins map to consensus baculovirus late transcription start sites (ATAAG), while the major 5' end of the transcript coding for the 40-kDa protein maps 16 nucleotides downstream from another late transcription start site sequence, GTAAG. Attempts to prepare recombinant viruses containing insertions within these three genes were negative, suggesting that they are all essential for virus replication in cell culture. The size and organization of transcripts expressed from this region of AcMNPV were very similar to those of the previously described homologous region of Orgyia pseudotsugata nuclear polyhedrosis virus (OpMNPV). The three AcMNPV protein sequences (p45, p40, and p12) showed amino acid sequence homology with the proteins p48, p45, and p12 of OpMNPV, suggesting this region is highly conserved in baculoviruses.

Amino Acid Sequence↗