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Biomedical subjects

T Jackson

Publications and source records attributed to T Jackson.

At least 19 recordsLinked to original sources
PubMed2005

Management of asymptomatic cholelithiasis for patients awaiting renal transplantation.

BACKGROUND: There is no consensus regarding the most appropriate management of asymptomatic cholelithiasis in patients awaiting renal transplantation. Cholecystectomy is considered before renal transplantation because of potential worsened complications from cholelithiasis with posttransplantation immunosuppression. This study reviewed the outcomes for operative and nonoperative management of asymptomatic cholelithiasis in patients awaiting renal transplantation. METHODS: A retrospective chart review of all patients who received renal transplant at the authors' institution during the period 1994 to 2000 was completed. All patients underwent pretransplantation abdominal ultrasound. RESULTS: Of the 411 patients receiving renal transplants (242 men and 169 women with a mean age of 45.7 years), 32 had cholelithiasis at the pretransplantation workup (7.8%), and 35 had gallbladder abnormalities (8.5%): polyps, thickened wall, sludge, bile duct dilation. Before transplantation, 12 of the 32 patients (38%) with cholelithiasis underwent uncomplicated cholecystectomy. None of the remaining 19 patients with cholelithiasis required cholecystectomy after renal transplantation (mean follow-up period 6.2 years). Of the 35 patients with gallbladder abnormalities, 2 required post transplantation elective cholecystectomy. CONCLUSIONS: No evidence was found for increased morbidity related to cholelithiasis or gallbladder abnormalities after renal transplantation. As in the general population, the risks associated with asymptomatic cholelithiasis do not appear to warrant prophylactic cholecystectomy for patients awaiting renal transplantation.

Adult↗
PubMed2005

Simple measures to reduce the rate of contamination of blood cultures in Accident and Emergency.

OBJECTIVES: To reduce the contamination rate of blood cultures taken in the Accident and Emergency (A&E) department. METHODS: The standard blood culture sampling kit was supplemented with an instruction sheet on the optimal method for drawing blood cultures and a large 62% ethyl alcohol impregnated wipe. RESULTS: There was a statistically significant reduction in the number of contaminants (p = 0.03). CONCLUSIONS: Simple measures to encourage skin disinfection and appropriate sampling technique will reduce the incidence of contamination of blood cultures in the A&E department.

Anti-Infective Agents, Local↗
PubMed2004

Quality of life as conveyed by pediatric patients with cancer.

Quality-of-life instruments have provided important advances in measuring the quality of life of pediatric patients receiving treatment for cancer. However, the bases of these instruments have not included first-hand reports from the patients; thus, these instruments may be conceptually incomplete. We directly solicited from pediatric patients their perspectives regarding their quality of life during treatment for cancer. We conducted two pilot studies: 23 patients (aged 8-15 years) participated in the first, a cross-sectional study; and 13 patients (aged 10-18 years) participated in the second, a 2-year longitudinal study. Data were analyzed by using a semantic-content method, and the following six domains were recognized in data from both of the studies: symptoms, usual activities, social/family interactions, health status, mood, and the meaning of being ill. These domains were compared with those of seven established pediatric oncology quality-of-life instruments, none of which included all six of these domains; the domain most frequently missing was the meaning of being ill domain. Here we present a new definition of the quality of life of pediatric oncology patients that is based on six domains; this definition may ensure the completeness and sensitivity of these important instruments.

Adolescent↗
PubMed2002

The IDDM13 region containing the insulin-like growth factor binding protein-5 (IGFBP5) gene on chromosome 2q33-q36 and the genetic susceptibility to rheumatoid arthritis.

We considered that the constitutive over-expression by cultured rheumatoid arthritis (RA) fibroblast-lineage synoviocytes of genes like IGFBP5 could indicate new candidate susceptibility genes. IGFBP5 is located in a region where an insulin-dependent diabetes mellitus (IDDM) susceptibility locus, IDDM13 (2q33-q36), has been mapped. Previous evidence that non-MHC IDDM loci overlap RA susceptibility loci made IGFBP5 and its region an interesting candidate locus which was tested for linkage. Forty-nine sibships (2-4 affected siblings per sibship) with RA were genotyped with microsatellite markers covering an 11.2 cM interval in the IGFBP5/IDDM13 region. Both the two-point LOD scores and a 'nonparametric' allele-sharing analysis revealed no evidence for linkage (max LOD = 0.54, P = 0.5, respectively). Adjustments for the presence of 'shared-epitope' alleles did not significantly change the LOD scores. These results suggest that, despite the involvement of the 2q33-q36 chromosomal region in another organ-specific autoimmune disease, it is unlikely that this region harbors a RA susceptibility locus.

Arthritis, Rheumatoid↗
PubMed2002

Multiphase mechanics of capsule formation in tumors.

The presence of a capsule around a tumor is known to be correlated with benign status, and the absence of a capsule often has negative implications for patient prognosis. A mechanical description is presented of the growth of a tumor and the resulting deformations of surrounding normal tissue. A mathematical model of the mechanics is analyzed using physical parameters measured in vivo and in vitro. The model has only three dimensionless parameters, and its results are very robust with respect to parameter variation. We show that the presence of contractility in the surrounding tissue, corresponding to a host defense, can make an existing capsule denser and constrain the tumor better, but cannot be responsible for the observed pressure gradients in encapsulated tumors. Some implications for treatment are discussed.

Cell Count↗
PubMed2001

Percutaneous absorption and skin irritation of JP-8 (jet fuel).

JP-8 is the major jet fuel used by US Army and Air Force. The purpose of the present study was to investigate the percutaneous absorption of JP-8 across pig ear skin and human skin in vitro and to study the effect of JP-8 exposure on the skin barrier function and irritation in Yucatan minipigs. JP-8 spiked with 5.0 microCi of radiolabeled (14C) tridecane, nonane, naphthalene or toluene (selected components of JP-8) was used for the in vitro percutaneous absorption studies with excised pig ear skin and human skin. For in vivo studies, 250 microl of JP-8 or two of its components (toluene or nonane) was placed in a Hill top chamber(R) and affixed over the marked treatment area for 24 h. Transepidermal water loss (TEWL), skin capacitance (moisture content) and skin irritation (erythema and edema) were evaluated before treatment and at 1,2 and 24 h after removal of the patches. The components of JP-8 such as tridecane, nonane, naphthalene and toluene permeated significantly through pig ear skin and human skin and the permeation rates were found to be proportional to their composition in JP-8. The steady state flux values of tridecane across pig ear skin and human skin did not differ significantly (P>0.05). Though the steady state flux values of nonane, naphthalene and toluene were statistically different between porcine and human skin (P<0.01), the values were close considering the large variations usually observed in the percutaneous absorption studies. Application of toluene, nonane or JP-8 increased the TEWL, JP-8 being the highest (3.5 times at 24 h compared to baseline level). The skin moisture content decreased after the application of JP-8, though it was not significantly different (P>0.05) from the baseline level. JP-8 caused a moderate erythema and a moderate to severe edema. Though the edema decreased after 24 h, the degree of erythema remained about the same until 24 h. The skin irritation caused by JP-8 was greater than neat toluene or nonane. The TEWL data of toluene, nonane and JP-8 correlated well with the skin irritation data (erythema and edema). Exposure of JP-8, which contains hundreds of aliphatic and aromatic hydrocarbons, caused significant changes in the barrier function of the skin as indicated by an increase in TEWL and produced a significant erythema and edema in minipigs. Furthermore, the disruption of barrier function of skin, as indicated by increased TEWL after exposure to JP-8 might result in increased permeation of its own components and/or other chemicals exposed to skin. The present study provides further evidence that pig ear skin may be used as a model for predicting the rates of permeation of chemicals through human skin.

Administration, Cutaneous↗
PubMed2001

Percutaneous permeation and skin irritation of JP-8+100 jet fuel in a porcine model.

JP-8 is the major jet fuel used by US Air Force. JP-8+100 is a new jet fuel recently introduced by the US Air Force, which contains JP-8 plus three performance additives [butylated hydroxytoluene (BHT), metal deactivator (MDA) and 8Q405]. The purpose of the present study was to investigate the percutaneous permeation of JP-8+100 across pig ear skin in vitro and to study the effect of JP-8+100 exposure on the skin barrier function, moisture content and irritation in Yucatan minipigs. The influence of performance additives on the permeation of JP-8 was studied by adding each additive individually to JP-8. The percutaneous permeation and skin irritation data obtained with JP-8+100 were compared with that of JP-8. JP-8+100 spiked with 5.0 microCi of radiolabeled [14C]tridecane, nonane, naphthalene or toluene (selected components of JP-8+100) was used for the in vitro percutaneous permeation studies. For skin irritation studies, 250 microl of JP-8+100 was placed in a Hill top chamber and affixed over the marked treatment area for 24 h. The components of JP-8+100 such as tridecane, nonane, naphthalene and toluene permeated readily through pig ear skin without any apparent lag time. Compared to JP-8, the permeation of tridecane, toluene and nonane from JP-8+100 was significantly lower (P<0.05). However, the permeation of naphthalene from JP-8+100 was significantly higher than from JP-8. When BHT was added to JP-8, the permeation of all four chemicals were significantly decreased (P<0.05). Though the addition of 8Q405 to JP-8 decreased the permeation of all four chemicals, the values were not significantly different (P>0.05) from that of JP-8. Addition of MDA did not show any significant change in the permeation of the selected chemicals from JP-8. Application of JP-8+100 increased the transepidermal water loss (TEWL) about three times compared to the baseline level. The skin moisture content decreased consistently after the application of JP-8+100, though it was not significantly different (P>0.05) from the baseline level. JP-8+100 caused a moderate erythema (score: 1.60) and a moderate to severe edema (score: 2.60). These results suggest that JP-8+100 produces significant changes in the barrier function of the skin and a local irritant effect upon occlusive dermal exposure. However there was no significant difference in the skin irritation data observed from JP-8 and JP-8+100.

Administration, Cutaneous↗
PubMed2001

Using computerised patient-level costing data for setting DRG weights: the Victorian (Australia) cost weight studies.

Casemix-funding systems for hospital inpatient care require a set of resource weights which will not inadvertently distort patterns of patient care. Few health systems have very good sources of cost information, and specific studies to derive empirical cost relativities are themselves costly. This paper reports a 5 year program of research into the use of data from hospital management information systems (clinical costing systems) to estimate resource relativities for inpatient hospital care used in Victoria's DRG-based payment system. The paper briefly describes international approaches to cost weight estimation. It describes the architecture of clinical costing systems, and contrasts process and job costing approaches to cost estimation. Techniques of data validation and reliability testing developed in the conduct of four of the first five of the Victorian Cost Weight Studies (1993-1998) are described. Improvement in sampling, data validity and reliability are documented over the course of the research program, the advantages of patient-level data are highlighted. The usefulness of these byproduct data for estimation of relative resource weights and other policy applications may be an important factor in hospital and health system decisions to invest in clinical costing technology.

Accounting↗
PubMed2001

Evaluation of skin sensitization potential of melatonin and nimesulide by murine local lymph node assay.

Melatonin is a good candidate for transdermal delivery considering its short plasma half life, low molecular weight and a favorable octanol:water partition coefficient. Nimesulide is a nonsteroidal anti-inflammatory agent used orally and rectally for inflammatory disorders. The objective of this study was to investigate the skin sensitization potential of melatonin and nimesulide using the standard murine local lymph node assay (LLNA). Melatonin (0.5, 2.5, 5.0 and 10.0%, w/v) and nimesulide (0.5, 2.5, 5.0 and 10.0%, w/v) dissolved in acetone:olive oil (4:1, AOO) was applied (25 microl) on the dorsal surface of each ear of female CBA/Ca mice for three consecutive days. On the sixth day, [3H]methyl thymidine was administered intravenously and the uptake of [3H]methyl thymidine (dpm) by the draining lymph nodes was determined by established methods. Dinitrochlorobenzene (DNCB, 0.25%, w/v) and para-aminobenzoic acid (PABA, 2.5%, w/v) were used as positive and negative control, respectively. The mean dpm obtained with melatonin and nimesulide treatment at all concentrations were not significantly different (P>0.05) from that of AOO. The stimulation index (SI) values of melatonin and nimesulide at different concentrations were close to 1. The results of the present study using the standard LLNA approved by US Interagency Coordinating Committee in the Validation of Alternative Methods (ICCVAM) indicate that melatonin and nimesulide are not skin sensitizers. However, since LLNA has shown false negatives with many drugs, clinical trials are certainly needed to exclude the possibility of a weak or delayed type skin sensitization reaction. Further studies using modified LLNA procedures (extended exposure, alternative vehicle systems, pre-abrasion, etc.) may be useful in identifying the weak or delayed type skin sensitization reactions.

Animals↗
PubMed2001

Paying for hospital emergency care under a single-payer system.

Hospital emergency services are one of the key drivers of hospital activity, yet there has been surprisingly little attention paid to appropriate funding models for single-payer systems, in which funders must be concerned with issues of access and financial viability of emergency departments. This article analyzes the dynamics of hospital emergency services in terms of the key products and cost drivers. It reviews the currently available systems for categorizing emergency activity and evaluates their applicability for funding purposes with particular emphasis on the susceptibility to gaming of both triage and disposition. It identifies and evaluates 3 models for use in single-payer health systems for funding hospital emergency services (fully variable, fully fixed, and mixed variable/fixed) in terms of the key products and cost drivers in the ED. Approaches to the setting and rebasing of fixed grants are considered. Problems of potential incentive effects and double payment for admitted patients make the setting of variable payments problematic, particularly for patients subsequently admitted as inpatients. Key characteristics of an ED funding model in single-payer systems are proposed.

Diagnosis-Related Groups↗
PubMed2001

Role of the cytoplasmic domain of the beta-subunit of integrin alpha(v)beta6 in infection by foot-and-mouth disease virus.

Field isolates of foot-and-mouth disease virus (FMDV) are believed to use RGD-dependent integrins as cellular receptors in vivo. Using SW480 cell transfectants, we have recently established that one such integrin, alpha(v)beta6, functions as a receptor for FMDV. This integrin was shown to function as a receptor for virus attachment. However, it was not known if the alpha(v)beta6 receptor itself participated in the events that follow virus binding to the host cell. In the present study, we investigated the effects of various deletion mutations in the beta6 cytoplasmic domain on infection. Our results show that although loss of the beta6 cytoplasmic domain has little effect on virus binding, this domain is essential for infection, indicating a critical role in postattachment events. The importance of endosomal acidification in alpha(v)beta6-mediated infection was confirmed by experiments showing that infection could be blocked by concanamycin A, a specific inhibitor of the vacuolar ATPase.

Acids↗
PubMed2001

Open thoracic meningocele associated with amniotic band syndrome.

We present a case of an infant born with an open thoracic meningocele secondary to an amniotic band. Although there have been several case reports of encephalocele, anencephaly, closed meningocele and a case of tethered cord associated with amniotic band syndrome (ABS), there has yet to be a report of an open meningocele associated with ABS. The patient remained neurologically intact after the repair of his meningocele. His postoperative course was complicated by meningitis with subsequent hydrocephalus necessitating ventriculoperitoneal shunt placement.

Amniotic Band Syndrome↗
PubMed2001

Attitudes towards prenatal HIV testing and treatment among pregnant women in southern India.

During June and July 1999, oral interviews were conducted on 666 women seeking prenatal care at 9 medical facilities in Chennai and Mysore, India, to assess their attitudes towards prenatal HIV testing and antiretroviral prophylaxis for preventing perinatal HIV transmission if needed. Seventy-eight per cent were aware of the risk of perinatal HIV transmission and 36% knew that intervention could reduce the chances of such transmission. Eighty-six per cent would agree to undergo prenatal HIV testing but only 21% of all respondents would make this decision independently while 46% said their husband would have to decide. Of those women who would not agree to testing, 21% would agree if testing were compulsory. Ninety-seven per cent of respondents would undergo antiretroviral prophylaxis to prevent vertical transmission, and 94% would consider alternatives to breastfeeding if HIV positive. Considering its widespread acceptability, prenatal voluntary counselling and testing may be an affordable method of HIV prevention for this population.

AIDS Serodiagnosis↗
PubMed2001

Axial computed tomography of the pedicle in the lower cervical spine.

Using axial computed tomography (CT), we measured pedicle width, pedicle axis length, pedicle transverse angle, and distance between screw entry point and vertebrae midline in the cervical spines (C3-C7) of 40 patients. All measurements were greater in men than in women, and we noted significant sex differences at most levels of pedicle inner and outer widths (P < or = .05 or P < or = .01). Mean pedicle inner and outer widths for all levels and all patients ranged from 2.3 to 3.0 mm and from 5.0 to 6.0 mm, respectively. Mean distances between screw entry point and vertebrae midline ranged from 22.2 to 23.7 mm. Results of this study-along with axial CT measurements of individual pedicle diameter, pedicle transverse angle, and screw entry point-would be useful when considering and performing transpedicular screw fixation in the cervical spine.

Adult↗