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Biomedical subjects

T Jackson

Publications and source records attributed to T Jackson.

At least 37 records · Page 2Linked to original sources
PubMed2000

A methodology designed to increase accuracy and safety in stereotactic brain surgery.

A series of technical tips and devices designed to increase accuracy and safety in stereotactic surgery are presented. We use stereotactic magnetic resonance imaging with three-dimensional magnetization-prepared rapid gradient-echo (MP-RAGE) imaging to minimize image distortion, and a three-dimensional stereotactic planning system for accurately registering three-dimensional space. We also developed several technical devices useful for stereotactic intracranial procedures; an applicator system attached to the frame which simulates the fiducial markers in order to keep the target at a suitable position in stereotactic space; a torque wrench to set the torque on the fixing pins to the frame reproducibly at 5 inch pounds in order to keep distortion of the frame to a minimum while maintaining secure fixation; an entry point marker to maintain the calculated trajectory angle; a straightening cannula to prevent the thermo-coagulation needle from bending; a microvascular Doppler and its holder to detect significant vessels and to know their precise depth in order to avoid vascular injury from thermocoagulation; a burr hole button device to secure depth electrode cables at the patient's skull.

Brain↗
PubMed2000

Part I: propofol, thiopental, sevoflurane, and isoflurane-A randomized, controlled trial of effectiveness.

UNLABELLED: When compared with thiopental and isoflurane, propofol and sevoflurane are associated with a faster return to wakefulness after anesthesia. Yet their wider usage in inpatient surgery has been restrained by concerns regarding their acquisition costs and by lack of studies demonstrating improved patient outcome. We randomly allocated 453 adult surgical inpatients to one of four anesthetic regimens (thiopental-isoflurane, propofol-isoflurane, propofol induction and maintenance, or sevoflurane induction and maintenance) and measured their rate and quality of recovery. We found no significant differences in the rate and quality of recovery between groups. Propofol was associated with more pain on injection (P: < 0. 0005), but less cough during induction (P: = 0.003), and less early postoperative nausea and vomiting (P: = 0.003). We could not detect any significant advantages with propofol and sevoflurane, when compared with thiopental and isoflurane in adults undergoing elective inpatient surgery. IMPLICATIONS: Propofol and sevoflurane do not offer any significant advantages over thiopental and isoflurane in adults undergoing elective inpatient surgery.

Adult↗
PubMed2000

Part II: total episode costs in a randomized, controlled trial of the effectiveness of four anesthetics.

UNLABELLED: Newer anesthetics promise improved clinical outcomes, but usually come at a higher price per dose. Previous studies have found few economic benefits in the immediate postoperative period, but have hypothesized that earlier recovery may lead to lower costs for the whole episode of hospitalization. This study uses cost data for patients enrolled in a randomized, controlled clinical trial comparing four anesthetics to test whether the higher costs of the newer anesthetics would be offset against decreased use of other hospital resources. Five hundred general surgery patients were randomly assigned to one of four anesthetic regimens. Estimates from the hospital's patient costing system were used, with validated cost records for a subset of 360 patients. Five patients admitted to the intensive care unit or requiring prolonged hospitalization skewed the distribution of costs, but none of these complications could be attributed to anesthesia. No significant differences were found on length of stay, mean episode cost, operating room costs, ward costs, or readmission rate within 3 mo. The study was not powered to sufficiently show differences in intensive care unit admission or other uncommon outcomes. Patient quality of recovery did not vary among groups, but neither patient willingness-to-pay nor satisfaction were directly measured. IMPLICATIONS: Propofol and sevoflurane do not offer any significant economic advantages over thiopental and isoflurane in adults undergoing elective inpatient surgery.

Adult↗
PubMed2000

Foot-and-mouth disease virus is a ligand for the high-affinity binding conformation of integrin alpha5beta1: influence of the leucine residue within the RGDL motif on selectivity of integrin binding.

Field isolates of foot-and-mouth disease virus (FMDV) use RGD-dependent integrins as receptors for internalization, whereas strains that are adapted for growth in cultured cell lines appear to be able to use alternative receptors like heparan sulphate proteoglycans (HSPG). The ligand-binding potential of integrins is regulated by changes in the conformation of their ectodomains and the ligand-binding state would be expected to be an important determinant of tropism for viruses that use integrins as cellular receptors. Currently, alphavbeta3 is the only integrin that has been shown to act as a receptor for FMDV. In this study, a solid-phase receptor-binding assay has been used to characterize the binding of FMDV to purified preparations of the human integrin alpha5beta1, in the absence of HSPG and other RGD-binding integrins. In this assay, binding of FMDV resembled authentic ligand binding to alpha5beta1 in its dependence on divalent cations and specific inhibition by RGD peptides. Most importantly, binding was found to be critically dependent on the conformation of the integrin, as virus bound only after induction of the high-affinity ligand-binding state. In addition, the identity of the amino acid residue immediately following the RGD motif is shown to influence differentially the ability of FMDV to bind integrins alpha5beta1 and alphavbeta3 and evidence is provided that alpha5beta1 might be an important FMDV receptor in vivo.

Amino Acid Motifs↗
PubMed2000

Cost estimates for hospital inpatient care in Australia: evaluation of alternative sources.

OBJECTIVE: This paper presents a framework for evaluation of alternative sources of estimates of the costs of hospital inpatient care in Australia. It argues that the choice of costing methods depends on the decision-context and the sensitivity of the decision to estimation errors. METHOD: Five criteria are proposed for evaluation of sources of hospital cost data, with detailed consideration of the way estimates are derived in two computerised approaches which use accounting data. Three broad approaches to cost estimation are evaluated against these criteria. RESULTS: Choosing an estimation method entails an optimisation analysis for each decision context. 'Microcosting' techniques remains the most valid approach to cost estimation, but are costly and this may, in turn, limit the sample of patients or institutions. Protocol-based cost estimates vary widely in their validity, depending on source data, but there is little justification for continued use of crude per diem cost estimates in such protocols. When precision and resolution are important objectives, clinical costing approaches provide the most valid inpatient cost estimates at a reasonable data cost. When external validity is important, or where standardisation of hospital costs is desired, use of published national cost weights may be preferred. CONCLUSION: Both primary and secondary sources of cost data must withstand challenges to internal and external validity. The 'resolution' (or precision) of cost estimates and the relative costs of collection must also be considered. IMPLICATIONS: Studies using estimates of the costs of hospital care should defend the appropriateness of the costing approach and data source for the decision context.

Accounting↗
PubMed2000

The epithelial integrin alphavbeta6 is a receptor for foot-and-mouth disease virus.

Field isolates of foot-and-mouth disease virus (FMDV) have been shown to use the RGD-dependent integrin alphavbeta3 as a cellular receptor on cultured cells. However, several other RGD-dependent integrins may have the potential to act as receptors for FMDV in vivo. Of these, alphavbeta6 is a likely candidate for use as a receptor by FMDV as it is expressed on epithelial cells, which correlates with the tissue tropism of the virus. In this report, we show that human colon carcinoma cells (SW480) that are normally nonpermissive for FMDV become susceptible to infection as a result of transfection with the integrin beta6 subunit and expression of alphavbeta6 at the cell surface. Integrin alphavbeta6 is the major site for virus attachment on the beta6-transfected cells, and binding to alphavbeta6 serves to increase the rate of virus entry into these cells. In addition, we show that virus binding and infection of the beta6-transfected cells is mediated through an RGD-dependent interaction that is specifically inhibited by a monoclonal antibody (10D5) that recognizes alphavbeta6. These studies establish a role for alphavbeta6 as a cellular receptor for FMDV.

Animals↗
PubMed2000

Culture and self-presentation as predictors of shyness among Japanese and American female college students.

Self-presentation theories of shyness have been supported in North American samples but have not been evaluated cross-culturally. This study examined the relative influence of cultural and psychological variables on self-reported shyness among Japanese and American college students. 35 female Japanese-born and 47 United States-born Euro-American female students completed the Shyness Scale, Rosenberg Self-esteem Scale, Interpersonal Competence Questionnaire, Sensitivity to Rejection Scale, and Individualism-Collectivism Scale, and a demographic data sheet. After statistically controlling for Individualism-Collectivism, psychological measures, especially perceived interpersonal competence and sensitivity to rejection, combined for Adjusted R2 = .32 in shyness. Findings suggest that similar factors are central to experiences of shyness for both samples. Researchers should assess the stability of such findings in larger, heterogeneous samples and evaluate whether treatment strategies that reduce expectations of rejection and increase perceived interpersonal competence have comparable efficacy in reducing shyness across cultures.

Cross-Cultural Comparison↗
PubMed1999

Did Wellington have too many acute psychiatric beds in 1996?

AIMS: (1) To establish whether, as believed by local clinicians, there is a shortage of acute psychiatric beds available in Wellington. (2) To compare the current situation with that of seven years ago, before the beginning of the reduction in bed numbers, as a part of deinstitutionalisation and care in the community. (3) To study the effect on occupancy of changing availability. METHOD: Data were obtained retrospectively for the calendar years 1996 and 1989. These were examined using an analysis of variance and the results of the two years were compared. RESULTS: There were 214 days in 1996 when there were no acute psychiatric beds available. The mean daily occupancy was 100%. Comparing like populations, there was a highly significant increase in the mean occupancy as the availability decreased from 1989 to 1996. Conversely, there was a decrease in occupancy as availability temporarily increased during 1996. CONCLUSION: The number of acute psychiatric beds available in Wellington in 1996 was insufficient to meet the needs of the population, given the alternative resources available at that time. This is of particular concern in light of proposals to reduce the number of beds further.

Analysis of Variance↗
PubMed1999

The structure and function of a foot-and-mouth disease virus-oligosaccharide receptor complex.

Heparan sulfate has an important role in cell entry by foot-and-mouth disease virus (FMDV). We find that subtype O1 FMDV binds this glycosaminoglycan with a high affinity by immobilizing a specific highly abundant motif of sulfated sugars. The binding site is a shallow depression on the virion surface, located at the junction of the three major capsid proteins, VP1, VP2 and VP3. Two pre-formed sulfate-binding sites control receptor specificity. Residue 56 of VP3, an arginine in this virus, is critical to this recognition, forming a key component of both sites. This residue is a histidine in field isolates of the virus, switching to an arginine in adaptation to tissue culture, forming the high affinity heparan sulfate-binding site. We postulate that this site is a conserved feature of FMDVs, such that in the infected animal there is a biological advantage to low affinity, or more selective, interactions with glycosaminoglycan receptors.

Adaptation, Physiological↗
PubMed1999

Differences in psychosocial experiences of employed, unemployed, and student samples of young adults.

The author conducted this cross-sectional study to assess the extent to which employed, unemployed, and student samples of young adults could be differentiated on the basis of psychosocial experiences. Forty-four employed, 41 unemployed, and 42 student volunteers completed measures of emotional distress, time structure, financial strain, skill use, task variety, social support, and demographic information. After the effects of educational and income differences were statistically controlled, results indicated that unemployed participants reported poorer functioning than employed and student respondents on most measures. In a discriminant function analysis, 66% of the sample was correctly identified from scores on psychosocial measures, with higher classification rates for employed and unemployed participants. The findings provide additional support for contextual models of mental health and suggest that full-time education partially buffers the negative psychological consequences of unemployment when opportunities for employment are absent.

Adaptation, Psychological↗
PubMed1999

Cost effectiveness of rotavirus vaccination in Australia.

OBJECTIVE: Rotavirus gastroenteritis causes substantial morbidity, including hospital admission, in young children. In the context of recent vaccine developments, this study aimed to estimate the cost-effectiveness of a rotavirus vaccination program in Australia. METHOD: Standard methods of health economic evaluation were used to assess the total cost of rotavirus immunisation (as the difference between estimated vaccination program costs and the cost of disease that would be avoided by immunisation) and relate this to the number of cases of disease that would be prevented. Estimates were made from both societal and health care systems perspectives. RESULTS: Based on Australian data on disease incidence and cost of hospitalisation, the current annual cost of rotavirus disease is about $26.0 million. Using conservative vaccine efficacy estimates, current immunization uptake rates and a cost of $30 per dose of vaccine, rotavirus immunisation would incur a net societal cost of $2.9 million ($11 per child), at a gross program cost of $21.6 million. These estimates are sensitive to two sources of uncertainty in the estimation of program delivery costs: vaccine price and whether separate immunization visits would be required. CONCLUSION: A rotavirus immunisation program would be cost-neutral to Australian society at a vaccine price of $26 per dose (or $19 when health care system costs only are considered). IMPLICATIONS: Rotavirus immunization may be cost-effective in Australia, but considerable uncertainty remains. Policy decisions will depend heavily on pricing of the vaccine and may also need to consider intangible costs not accounted for in this analysis.

Child, Preschool↗
PubMed1999

Influence of the teacher-student relationship on childhood conduct problems: a prospective study.

Examined the influence of the quality of the teacher-student relationship on children's subsequent levels of aggression in a sample of 61 second and third-grade children nominated and rated by their teachers as aggressive. The stability of teachers' and children's reports of relationships quality across academic years was in the low to moderate range. Teachers and children showed little agreement in their reports of relationship quality. Teachers' and children's reports of relationship quality in year 1 (Y1) predicted teacher-rated aggression the following year, controlling for Y1 ratings of aggression. Teachers' reports of relationship quality across Y1 and Y2 predicted peer-rated aggression, but not teacher-rated aggression, in Y3, controlling for Y1 aggression. Consistent with a buffering role for teacher-student relationships, a positive teacher-student relationship was of greatest benefit to children whose mothers reported rejecting parenting histories. We discuss implications for school-based prevention programs.

Aggression↗
PubMed1999

Two brothers with varying combinations of severe developmental delay, epilepsy, microcephaly, tetralogy of Fallot and hydronephrosis.

We report on a sib pair who manifest a pattern of anomalies which appears to be unique and for which we are unable to provide a cytogenetic or molecular genetic explanation. While a number of their physical features are distinct, their overall appearance and pattern of neurological impairment suggest they suffer from the same genetic disorder.

Abnormalities, Multiple↗
PubMed1998

Transport vesicles: coats of many colours.

Clathrin-coated vesicles transport proteins and membranes between intracellular compartments. Adaptor molecules determine vesicle specificity; recently, a third type of adaptor protein, AP3, has been identified and implicated in the biogenesis of endosomal and lysosome-related organelles.

Adaptor Protein Complex 3↗
PubMed1998

Atmosphere-surface interactions on Mars: delta 17O measurements of carbonate from ALH 84001.

Oxygen isotope measurements of carbonate from martian meteorite ALH 84001 (delta18O = 18.3 +/- 0.4 per mil, delta17O = 10.3 +/- 0.2 per mil, and Delta17O = 0.8 +/- 0.05 per mil) are fractionated with respect to those of silicate minerals. These measurements support the existence of two oxygen isotope reservoirs (the atmosphere and the silicate planet) on Mars at the time of carbonate growth. The cause of the atmospheric oxygen isotope anomaly may be exchange between CO2 and O(1D) produced by the photodecomposition of ozone. Atmospheric oxygen isotope compositions may be transferred to carbonate minerals by CO2-H2O exchange and mineral growth. A sink of 17O-depleted oxygen, as required by mass balance, may exist in the planetary regolith.

Atmosphere↗
PubMed1998

Relations of employment status to emotional distress among chronic pain patients: a path analysis.

OBJECTIVE: This cross-sectional study evaluated the extent to which relations between employment status and emotional distress are mediated by pain-related and psychosocial measures among employed and unemployed persons with chronic pain. DESIGN: A total of 40 unemployed and 43 employed persons reporting chronic pain were recruited from pain services at a tertiary-care hospital and community-based organizations. Volunteers completed self-report measures of pain severity, subjective financial stress, time structure, emotional distress, and background data. RESULTS: A path analysis indicated that pain severity had direct associations with both emotional distress and employment status. In addition, employment status was only indirectly related to emotional distress; this relation was mediated by levels of reported financial strain and structured purposeful time use. CONCLUSIONS: Findings suggest that pain severity and the quality of specific experiences related to being employed or unemployed as opposed to employment status per se correspond directly to levels of emotional distress reported by some persons with chronic pain.

Adult↗
PubMed1998

Preliminary investigation of associations of illness schemata and treatment-induced reduction in headaches.

This study examined how illness schemata-ways people organize information about illness-change over the course of cognitive-behavioral treatment of chronic headache and the extent to which such changes predict reduction of headache. 73 subjects with chronic migraine, mixed migraine and tension, or tension headache were classified on the basis of outcome from imagery-based treatment as Treatment-responders (n = 24). Treatment nonresponders (n = 27), and Monitoring Controls (n = 22). Self-reported illness schemata related to the seriousness and changeability of headache were assessed at pretreatment and 8-wk. follow-up. While groups did not differ on pretreatment measures of illness schemata, at follow-up the Treatment responder group reported higher Changeability scores than Treatment-nonresponders and Control subjects and lower Seriousness scores than Control subjects. Headache reduction at follow-up was related to follow-up Changeability scores, in-session changes in systolic blood pressure and reported posttreatment expectations of headache activity, but not pretreatment measures of illness schemata. Findings indicate that improvements in headache activity are not influenced by the severity of headaches and may change prior to cognitive-behavioral treatment. Rather, among individuals who show decreases in headache activity, changes in beliefs about illness and headache reduction may have reciprocal relations both of which result from cognitive behavioral treatment.

Adult↗