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Biomedical subjects

L Smith

Publications and source records attributed to L Smith.

At least 37 records · Page 2Linked to original sources
PubMed2001

Differential expression of the early lung cancer detection marker, heterogeneous nuclear ribonucleoprotein-A2/B1 (hnRNP-A2/B1) in normal breast and neoplastic breast cancer.

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP-A2/B1) is highly expressed during critical stages of lung development and carcinogenesis. To determine if the expression of hnRNP-A2/B1 is an informative biomarker in breast carcinogenesis, we analyzed hnRNP-A2/B1 overexpression by immunohistochemistry in archived specimens. Expression was detected in 48/85 (56.5%) primary invasive breast cancers and 7/72 (9.7%) specimens of normal breast tissue. Northern analysis of breast cancer cells also demonstrated higher level of hnRNP-A2/B1 expression compared to normal or transformed breast cells. Expression of hnRNP-A2/B1 in breast cancer cells was decreased by exposure to retinoids coordinately with decreased cell growth. These results warrant further evaluation of hnRNP-A2/B1 as a marker of breast carcinogenesis.

Biomarkers, Tumor↗
PubMed2001

Acetylation control of the retinoblastoma tumour-suppressor protein.

The retinoblastoma tumour-suppressor protein (pRb) and p300/CBP co-activator proteins are important for control of proliferation and in tumour cells these are sequestered by viral oncoproteins such as E1A. pRb is involved in negatively regulating growth, and p300/CBP proteins have histone acetyltransferase (HAT) activity, which influences gene expression. Although it is known that phosphorylation by G1 cyclin-dependent kinases (CDKs) regulates pRb activity, the nature and role of other post-translational modifications is not understood. Here we identify acetylation as a new type of modification and level of control in pRb function. Adenovirus E1A, which binds p300/CBP through an amino-terminal transformation-sensitive domain, stimulates the acetylation of pRb by recruiting p300 and pRb into a multimeric-protein complex. Furthermore, pRb acetylation is under cell-cycle control, and acetylation hinders the phosphorylation of pRb by cyclin-dependent kinases. pRb binds more strongly when acetylated to the MDM2 oncoprotein, which indicates that acetylation may regulate protein-protein interactions in the pRb pathway. The acetylation of pRb defines a new level of cell-cycle control mediated by HAT. Furthermore, our results establish a relationship between p300, pRb and acetylation in which E1A acts to recruit and target a cellular HAT activity to pRb.

Acetylation↗
PubMed2001

Development of spontaneous factor VIII inhibitor in association with acute graft-versus-host disease.

A 57-year-old female with recurrent AML underwent a T cell-depleted (TCD) bone marrow (BM) plus TCD and CD34-selected peripheral blood stem cell (PBSC) transplant. Eleven weeks post transplantation, the patient developed acute graft-versus-host disease (GVHD) manifested by rash and elevated liver enzymes. Concurrently, the patient presented with a bleeding diathesis and a left forearm hematoma due to the development of a spontaneous factor VIII inhibitor. She was treated with human recombinant factor VIII and intravenous methylprednisolone. Subsequently she was managed with a prednisone taper leading to resolution of the GVHD, as well as the spontaneous factor VIII inhibitor. Bone marrow transplant-related spontaneous factor VIII inhibitor has previously been reported in association with one patient with chronic GVHD. To our knowledge this is the first report of spontaneous factor VIII inhibitor associated with acute GVHD.

Acute Disease↗
PubMed2001

Allele-specific quantification of tumor necrosis factor alpha (TNF) transcription and the role of promoter polymorphisms in rheumatoid arthritis patients and healthy individuals.

Interindividual variation in the expression of tumor necrosis factor alpha (TNF) suggests the existence of functionally distinct TNF alleles that could play a role in susceptibility to TNF associated diseases such as rheumatoid arthritis (RA). To determine whether differential expression of TNF alleles exists, the relative contribution of TNF alleles in total TNF RNA production in peripheral blood mononuclear cells (PBMC) of healthy individuals and synovial tissue of RA patients was analyzed. By using a Tai I restriction fragment length polymorphism (RFLP) located at position +489 in the first intron of the gene, the relative contribution of each allele in precursor transcript production in heterozygous individuals could be measured. By means of this method we studied whether differences exist between TNF alleles in TNF pre-mRNA production. The relative contribution of TNF alleles to the non-spliced RNA pool was measured in PBMC of healthy individuals which were stimulated with LPS, PMA and anti-CD3 and anti-CD28 monoclonal antibodies for different time periods. Moreover, synovial biopsy material of RA patients was analyzed. The results of this study do not reveal a difference in the contribution of distinct TNF alleles in TNF pre-mRNA production upon in vitro and physiological stimulation conditions in healthy individuals and RA patients. Since some of the individuals whose PBMC were tested were also heterozygous for either -308, -1031, -863, -857 TNF promoter/enhancer single nucleotide polymorphisms (SNPs), the data argue against functional relevance of these TNF promoter/enhancer SNPs in the regulation of transcription. In conclusion, the data do not provide evidence for the existence of transcriptionally distinct TNF alleles to explain interindividual variation in TNF expression.

Alleles↗
PubMed2001

Segmental mandibular reconstruction by microincremental automatic distraction osteogenesis: an animal study.

We investigated the reconstruction of a surgically created critical size mandibular defect in sheep using a newly developed automatic distraction device. The device has an implantable component, which is fixed to the mandible to allow the transfer of the transport disc across the created defect, and an external component which is mounted on the activation pump and secured away from the site of bone distraction. Compression of the bellows in the external component causes fluid to be forced through the connecting tube into the distraction component. Distraction at a rate of 1 mm over 24 h was achieved in six sheep. New bone generated at the site of the created defects both anterior (compression side) and posterior (tension side) to the transport disc and had similar radiodensity to the adjacent mandibular bone eight weeks after the completion of distraction.

Angiography↗
PubMed2001

In vitro human tissue models in risk assessment: report of a consensus-building workshop.

Advances in the technology of human cell and tissue culture and the increasing availability of human tissue for laboratory studies have led to the increased use of in vitro human tissue models in toxicology and pharmacodynamics studies and in quantitative modeling of metabolism, pharmacokinetic behavior, and transport. In recognition of the potential importance of such models in toxicological risk assessment, the Society of Toxicology sponsored a workshop to evaluate the current status of human cell and tissue models and to develop consensus recommendations on the use of such models to improve the scientific basis of risk assessment. This report summarizes the evaluation by invited experts and workshop attendees of the current status of such models for prediction of human metabolism and identification of drug-drug interactions, prediction of human toxicities, and quantitative modeling of pharmacokinetic and pharmaco-toxicodynamic behavior. Consensus recommendations for the application and improvement of current models are presented.

Cell Culture Techniques↗
PubMed2001

Hyperbaric oxygen therapy for severe ulcerative colitis.

Hyperbaric oxygen therapy has been used to successfully treat perineal Crohn's disease. We describe the first successful use of hyperbaric oxygen therapy in the treatment of ulcerative colitis, refractory to conventional therapies. Therapy consisted of 30 courses of 100% oxygen at a pressure of 2.0 atm absolute. Clinical remission was achieved on the basis of the Truelove-Witts and disease activity index scores. Corticosteroids were successfully tapered off once remission was achieved.

Adult↗
PubMed2001

Creatine supplementation and health variables: a retrospective study.

PURPOSE: Long-term safety of creatine supplementation has been questioned. This retrospective study was performed to examine markers related to health, the incidence of reported side effects and the perceived training benefits in athletes supplementing with creatine monohydrate. METHODS: Twenty-six athletes (18 M and 8 F, 24.7 +/- 9.2 y; 82.4 +/- 20.0 kg; 176.5 +/- 8.8 cm) from various sports were used as subjects. Blood was collected between 7:00 and 8:30 a.m. after a 12-h fast. Standard clinical examination was performed for CBC and 27 blood chemistries. Testosterone, cortisol, and growth hormone were analyzed using an ELISA. Subjects answered a questionnaire on dietary habits, creatine supplementation, medical history, training history, and perceived effects of supplementation. Body mass was measured using a medical scale, body composition was estimated using skinfolds, and resting heart rate and blood pressure were recorded. Subjects were grouped by supplementation length or no use: Gp1 (control) = no use (N = 7; 3 F, 4 M); Gp2 = 0.8-1.0 yr (N = 9; 2 F, 7 M); and Gp3 = 1(+) (N = 10; 3 F, 7 M). RESULTS: Creatine supplementation ranged from 0.8--4 yr. Mean loading dose for Gp2 and Gp3 was 13.7 +/- 10.0 and the maintenance dose was 9.7 +/- 5.7 g.d(-)1. Group differences were analyzed using one-way ANOVA. CONCLUSIONS: Expected gender differences were observed. Of the comparisons made among supplementation groups, only two differences for creatinine and total protein (P < 0.05) were noted. All group means fell within normal clinical ranges. There were no differences in the reported incidence of muscle injury, cramps, or other side effects. These data suggest that long-term creatine supplementation does not result in adverse health effects.

Adolescent↗
PubMed2001

HLA-B27 expression does not modulate intracellular Chlamydia trachomatis infection of cell lines.

Chlamydia trachomatis is an obligate intracellular pathogen. Infection of susceptible individuals with this bacterium can trigger the development of reactive arthritis, an acute inflammation that is associated with the expression of the class I major histocompatibility antigen, HLA-B27. Other facultative intracellular pathogens, such as Yersinia and Salmonella spp., are also known triggers of reactive arthritis. Previous studies report conflicting results concerning whether the presence of HLA-B27 modulates the infection of cells with these enteric pathogens. In the present study, we have examined whether the expression of HLA-B27 can influence the infection of cell lines with C. trachomatis and also whether the replication of these bacteria is altered in HLA-B27-expressing cell lines. To do this, we have used a sensitive flow cytometric approach. We fixed and permeabilized cells and used fluorescein isothiocyanate-conjugated monoclonal antibody specific for chlamydia lipopolysaccharide to detect intracellular bacteria. The staining pattern obtained closely resembled the intracellular life cycle of chlamydia, with the appearance of brightly staining cells correlating to the microscopic detection of mature inclusion bodies. Moreover, since the percentage of cells that stained with the antibody was proportional to the infectious inoculum used, we were able to use the technique to quantitate the number of infectious organisms recoverable from infected cell lines. An important component of our study was the use of heparin to prevent reinfection of cells and thus enable the infection to be followed from a discrete time point. Our results suggest that HLA-B27 influences neither the infection nor replication of C. trachomatis serovar L2 within cell lines. Consequently, the role of HLA-B27 in the pathogenesis of reactive arthritis may lie downstream of the invasion and replication stages of the triggering pathogenic infection.

Cell Line↗
PubMed2001

Mechanism of endothelial dysfunction in apolipoprotein E-deficient mice.

Endothelium-dependent relaxations mediated by NO are impaired in a mouse model of human atherosclerosis. Our objective was to characterize the mechanisms underlying endothelial dysfunction in aortas of apolipoprotein E (apoE)-deficient mice, treated for 26 to 29 weeks with a lipid-rich Western-type diet. Aortic rings from apoE-deficient mice showed impaired endothelium-dependent relaxations to acetylcholine (10(-)(9) to 10(-)(5) mol/L) and Ca(2+) ionophore (10(-)(9) to 10(-)(6) mol/L) and endothelium-independent relaxations to diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA-NONOate, 10(-)(10) to 10(-)(5) mol/L) compared with aortic rings from C57BL/6J mice (P<0.05). By use of confocal microscopy of an oxidative fluorescent probe (dihydroethidium), increased superoxide anion (O(2)(-)) production was demonstrated throughout the aortic wall but mainly in smooth muscle cells of apoE-deficient mice. CuZn-superoxide dismutase (SOD) and Mn-SOD protein expressions were unaltered in the aorta exposed to hypercholesterolemia. A cell-permeable SOD mimetic, Mn(III) tetra(4-benzoic acid) porphyrin chloride (10(-)(5) mol/L), reduced O(2)(-) production and partially normalized relaxations to acetylcholine and DEA-NONOate in apoE-deficient mice (P<0.05). [(14)C]L-Citrulline assay showed a decrease of Ca(2+)-dependent NOS activity in aortas from apoE-deficient mice compared with C57BL/6J mice (P<0.05), whereas NO synthase protein expression was unchanged. In addition, cGMP levels were significantly reduced in the aortas of apoE-deficient mice (P<0.05). Our results demonstrate that in apoE-deficient mice on a Western-type fat diet, impairment of endothelial function is caused by increased production of O(2)(-) and reduced endothelial NO synthase enzyme activity. Thus, chemical inactivation of NO with O(2)(-) and reduced biosynthesis of NO are key mechanisms responsible for endothelial dysfunction in aortas of atherosclerotic apoE-deficient mice.

Animals↗
PubMed2001

Similar effects on infants of n-3 and n-6 fatty acids supplementation to pregnant and lactating women.

OBJECTIVE: There have been indications that high intake of n-3 long-chain polyunsaturated fatty acids (PUFAs) during pregnancy may increase birth weight and gestational length. In addition, n-3 long-chain PUFAs may be important for the neurobiological development of the infants. High levels of docosahexaenoic acid (DHA, 22:6 n-3) are found in the gray matter of the cerebral cortex and in the retina, and it seems as if the availability of long-chain PUFAs may be limiting cerebral development. The fetus and the newborn are dependent on a high supply from their mothers, either via the placenta or via breast milk. We supplemented pregnant and lactating women with n-3 or n-6 long-chain PUFAs to evaluate the effect on birth weight, gestational length, and infant development. DESIGN: We performed a double-blind, randomized study recruiting 590 pregnant, healthy, nulli- or primiparous women (19-35 years old) in weeks 17 to 19 of pregnancy. The women were provided 10 mL of either cod liver oil or corn oil daily until 3 months after delivery. MAIN OUTCOME MEASURES: Primary outcomes were gestational length and birth weight. Electroencephalography (EEG) was done on the second day of life and at 3 months of age. Novelty preference (Fagan test) was used as an indicator of cognitive function at 6 and 9 months of age. The fatty acid pattern in umbilical plasma phospholipids and in breast milk was measured, and dietary assessments were performed, both on the mothers during pregnancy and on the infants at 3 months of age. The growth of the infants was followed up to 1 year of age. RESULTS: Three hundred forty-one mothers took part in the study until delivery. There were no significant differences in maternal body mass index before pregnancy and at birth, or parity between the 2 groups. Smoking habits and parental education were also similar in the 2 groups. The mean age of the mothers receiving cod liver oil was, by chance, 1 year higher than the age of the mothers receiving corn oil (28.6 [3.4] vs 27.6 [3.2] years). The maternal dietary intake in the 2 groups receiving cod liver oil or corn oil was similar, except for the supplementation. There were no differences in gestational length or birth weight between the cod liver oil group and the corn oil group (279.6 [9.2] vs 279.2 [9.3] days; 3609 [493] vs 3618 [527] g, respectively). Birth length, head circumference, and placental weight were also similar in the 2 groups. The concentrations of the n-3 fatty acids eicosapentaenoic acid (20:5 n-3), docosapentaenoic acid (22:5 n-3), and DHA in umbilical plasma phospholipids were higher in the cod liver oil group compared with the corn oil group (10.8 [7.6] vs 2.5 [1.8] microg/mL, 5.0 [2.6] vs 2.9 [1.3] microg/mL, 55.8 [20.6] vs 45.3 [12.8] microg/mL, respectively). Neonates with high concentration of DHA in umbilical plasma phospholipids (upper quartile) had longer gestational length than neonates with low concentration (lower quartile; 282.5 [8.5] vs 275.4 [9.3] days). No differences in EEG scores or Fagan scores were found, but neonates with mature EEG (N = 70) had a higher concentration of DHA in umbilical plasma phospholipids than neonates with immature EEG (N = 51) on the second day of life. Dietary information from 251 infants at 3 months of age was collected and 85% of these infants were exclusively breastfed, in addition to 12% who were partly breastfed. The breast milk of mothers supplemented with cod liver oil contained more n-3 long-chain PUFAs and less n-6 long-chain PUFAs than breast milk of mothers supplemented with corn oil. There were no significant differences in infant growth during the first year of life between the 2 groups. CONCLUSIONS: This study shows neither harmful nor beneficial effects of maternal supplementation of long-chain n-3 PUFAs regarding pregnancy outcome, cognitive development, or growth, as compared with supplementation with n-6 fatty acids. However, it confirms that DHA concentration may be related to gestational length and cerebral maturation of the newborn.

Abnormalities, Multiple↗
PubMed2001

A new module in caring for older adults: problem-based learning and practice portfolios.

It is not often that educators have the chance to design a new educational program on the basis of up-to-date and locally relevant research findings. We describe the process by which we designed a new module, aimed at registered nurses who care for older adults in the community. The content of the new module was derived from an analysis of educational needs of the potential student population. The mode of delivery was strongly student-centered, using problem-based learning. Assessment was through the building up by students of a practice portfolio. This paper focuses on a description of the new module and how it relates to the findings of the educational needs analysis. The National Board for Nursing, Midwifery and Health Visiting for Scotland put out a tender in 1995 for a community research project on "Educational Provision for Evolving Roles in Community Health Care" (Nursing Times, June, 9, 1995) with the aim of piloting and evaluating an "innovative program which meets changing needs in community health care." A joint bid by Napier University and the University of Glasgow not only proposed to pilot and evaluate the educational program, but also first to develop the content of the program itself through an educational needs analysis. In this paper, we will first provide an outline of the research that underpinned the educational program. Then, we will describe how the results of the needs analysis were implemented into an innovative educational module. Finally, we will give a brief summary of the new module.

Aged↗
PubMed2000

Activation of atypical protein kinase C zeta by caspase processing and degradation by the ubiquitin-proteasome system.

Atypical protein kinase C zeta (PKCzeta) is known to transduce signals that influence cell proliferation and survival. Here we show that recombinant human caspases can process PKCzeta at three sites in the hinge region between the regulatory and catalytic domains. Caspase-3, -6, -7, and -8 chiefly cleaved human PKCzeta at EETD downward arrowG, and caspase-3 and -7 also cleaved PKCzeta at DGMD downward arrowG and DSED downward arrowL, respectively. Processing of PKCzeta expressed in transfected cells occurred chiefly at EETD downward arrowG and DGMD downward arrowG and produced carboxyl-terminal polypeptides that contained the catalytic domain. Epitope-tagged PKCzeta that lacked the regulatory domain was catalytically active following expression in HeLa cells. Induction of apoptosis in HeLa cells by tumor necrosis factor alpha plus cycloheximide evoked the conversion of full-length epitope-tagged PKCzeta to two catalytic domain polypeptides and increased PKCzeta activity. A caspase inhibitor, zVAD-fmk, prevented epitope-tagged PKCzeta processing and activation following the induction of apoptosis. Induction of apoptosis in rat parotid C5 cells produced catalytic domain polypeptides of endogenous PKCzeta and increased PKCzeta activity. Caspase inhibitors prevented the increase in PKCzeta activity and production of the catalytic domain polypeptides. Treatment with lactacystin, a selective inhibitor of the proteasome, caused polyubiquitin-PKCzeta conjugates to accumulate in cells transfected with the catalytic domain or full-length PKCzeta, or with a PKCzeta mutant that was resistant to caspase processing. We conclude that caspases process PKCzeta to carboxyl-terminal fragments that are catalytically active and that are degraded by the ubiquitin-proteasome pathway.

Animals↗
PubMed2000

A novel ATPase on mouse chromosome 7 is a candidate gene for increased body fat.

A region of mouse chromosome 7, just distal to the pink-eyed (p) dilution locus, contains a gene or genes, which we have named p-locus-associated obesity (plo1), affecting body fat. Mice heterozygous for the most distally extending chromosomal deletions of this region have nearly double the body fat of mice when the deletion is inherited maternally as when it is inherited paternally. We have physically mapped the 1-Mb critical region, which lies between the Gabrb3 and Ube3a/Ipw genes, and DNA sequencing has localized a new member of the third subfamily of P-type ATPases to the minimal region specifying the trait. This gene, which we have called p-locus fat-associated ATPase (pfatp) is differentially expressed in human and mouse tissues with predominant expression in the testis and lower levels of expression in adipose tissue and other organs. We propose this ATPase as the prime candidate for the gene at the plo1 locus modulating body fat content in the mouse. The unusual inheritance pattern of this phenotype suggests either genomic imprinting, known to occur in other local genes (Ube3a, Ipw), or an effect of maternal haploinsufficiency during pregnancy or lactation on body fat in the progeny.

Adenosine Triphosphatases↗
PubMed2000

Activation of protein kinase C induces nuclear translocation of RFX1 and down-regulates c-myc via an intron 1 X box in undifferentiated leukemia HL-60 cells.

Treatment of human promyelocytic leukemia cells (HL-60) with phorbol 12-myristate 13-acetate (PMA) is known to decrease c-myc mRNA by blocking transcription elongation at sites near the first exon/intron border. Treatment of HL-60 cells with either PMA or bryostatin 1, which acutely activates protein kinase C (PKC), decreased the levels of myc mRNA and Myc protein. The inhibition of Myc synthesis accounted for the drop in Myc protein, because PMA treatment had no effect on Myc turnover. Treatment with PMA or bryostatin 1 increased nuclear protein binding to MIE1, a c-myc intron 1 element that defines an RFX1-binding X box. RFX1 antiserum supershifted MIE1-protein complexes. Increased MIE1 binding was independent of protein synthesis and abolished by a selective PKC inhibitor, which also prevented the effect of PMA on myc mRNA and protein levels and Myc synthesis. PMA treatment increased RFX1 in the nuclear fraction and decreased it in the cytosol without affecting total RFX1. Transfection of HL-60 cells with myc reporter gene constructs showed that the RFX1-binding X box was required for the down-regulation of reporter gene expression by PMA. These findings suggest that nuclear translocation and binding of RFX1 to the X box cause the down-regulation of myc expression, which follows acute PKC activation in undifferentiated HL-60 cells.

Active Transport, Cell Nucleus↗
PubMed2000

Complications from radiotherapy dose escalation in prostate cancer: preliminary results of a randomized trial.

OBJECTIVE: To compare early and late side effects in prostate cancer patients with Stage T1b-T3 disease randomized to receive 70 Gy or 78 Gy. METHODS: There were 189 patients randomized with a minimum follow-up of 2 years, that were available for this analysis. All patients were initially treated with a 4-field box to an isocenter dose of 46 Gy at 2 Gy per fraction. In the 70-Gy arm, treatment was continued to a reduced volume using a 4-field box technique. In the 78-Gy arm, treatment was continued to a reduced volume using a conformal 6-field arrangement. Side effects were graded on a 1-4 scale, adapted from Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force criteria. RESULTS: No significant differences in acute rectal or bladder toxicity were seen between the two treatment techniques (p > 0.6 for all comparisons). The 5-year Kaplan-Meier risks of Grade 2 or higher late bladder toxicity were 20% and 9% for 70-Gy and 78-Gy groups, respectively (log rank, p = 0.8). The 5-year risks of Grade 2 or higher late rectal toxicity were 14% and 21% for 70 Gy and 78 Gy, respectively (p = 0.4). Dose-volume histogram analysis of the 78-Gy patients showed a significant correlation between the percentage of rectum irradiated to 70 Gy or greater and the likelihood of developing late rectal complications. Patients with more than 25% of the rectum receiving 70 Gy or greater had a 5-year risk of Grade 2 or higher complications of 37% compared to 13% for patients with 25% or less (p = 0.05). All three Grade 3 complications occurred when greater than 30% of the rectum received 70 Gy or more. CONCLUSION: The overall rate of complications was similar in both treatment arms. However, there is evidence for a significant increase in late rectal complications when more than 25% of the rectum received 70 Gy or greater. This parameter may serve as a benchmark for the design of future three-dimensional conformal trials.

Aged↗