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Biomedical subjects

R J Shaw

Publications and source records attributed to R J Shaw.

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

Cerebral bioenergetics in stable chronic obstructive pulmonary disease.

Cerebral intracellular energy production (cerebral bioenergetics) via oxidative phosphorylation and the production of adenosine triphosphate (ATP) is critical to cerebral function. To test the hypothesis that patients with chronic stable hypoxia also generate neuronal ATP via an anaerobic metabolism, we studied the changes in cerebral (31)P magnetic resonance spectra ((31)P MRS) in patients with stable chronic obstructive pulmonary disease (COPD), and compared the results with MR spectra from similar areas of the brain in control subjects. Ten patients with stable COPD (age: 65 +/- 9 yr [mean +/- SD]; Pa(O(2)): 8.8 +/- 1.2 kPa; Pa(CO(2)): 6.1 +/- 0.8 kPa; pH 7.42 +/- 0.03, and FEV(1): 41 +/- 20% predicted) and five healthy volunteers underwent cerebral (31)P MRS (TR-5,000 ms) at 1.5 T. When COPD patients were compared with controls, the percentage MR signal with respect to total MR-detectable phosphorus-containing metabolites was increased from inorganic phosphate (Pi) (7.1 +/- 1. 3% versus 3.9 +/- 0.7%, p = 0.0001) and phosphomonoesters (PMEs) (9. 4 +/- 1.2% versus 6.9 +/- 0.3%, p = 0.0001), whereas the signal from phosphodiesters was reduced (34.8 +/- 3.2 versus 40.4 +/- 3.3%, p = 0.015). The ratios of Pi to betaATP (0.8 +/- 0.2 versus 0.4 +/- 0.1, p = 0.001) and of PME to betaATP (1.0 +/- 0.2 versus 0.7 +/- 0.1, p = 0.015) were increased, but the phosphocreatine-to-Pi ratio (2.1 +/- 0.6 versus 3.2 +/- 0.6, p = 0.01) was reduced in patients as compared with controls. This alteration in phosphorus-containing metabolites within cerebral cells provides evidence of extensive use of anaerobic metabolism in hypoxic COPD patients.

Adenosine Triphosphate↗
PubMed1998

Regulation of the neurofibromatosis type 2 tumor suppressor protein, merlin, by adhesion and growth arrest stimuli.

The neurofibromatosis type 2 tumor suppressor gene is inactivated in the development of familial and sporadic schwannomas and meningiomas. The encoded protein, Merlin, is closely related to the Ezrin, Radixin, and Moesin family of membrane/cytoskeletal linker proteins. Examination of Merlin in several cell lines revealed that the protein migrates as two distinct species near 70 kDa. Phosphatase treatment and orthophosphate labeling demonstrated that the species with decreased mobility is phosphorylated. Given Merlin's localization to cortical actin structures, we examined the effect of cell-cell contact or other forms of growth arrest on Merlin expression and post-translational modification. Under conditions of confluency or serum deprivation, the levels of phosphorylated and unphosphorylated Merlin species increased significantly. Cells arrested in G1 by other methods or other phases of the cell cycle did not show changes in Merlin levels. Furthermore, loss of adhesion resulted in a nearly complete dephosphorylation of Merlin, which was reversed upon re-plating of cells, suggesting Merlin phosphorylation may be responsive to cell spreading or changes in cell shape. Thus, the tumor suppressor function of Merlin may involve the regulation of cellular responses to cues such as cell-cell contact, growth factor microenvironment, or changes in cell shape.

3T3 Cells↗
PubMed1998

Serum IgE responses during primary and challenge infections of sheep with Trichostrongylus colubriformis.

Serum IgE responses during primary or challenge infections with Trichostrongylus colubriformis were examined by measuring total IgE and parasite-specific IgE by ELISA. Three- to four-month-old lambs reared nematode-free received a single primary infection of 30,000 T. colubriformis-infective larvae (TcL3). Infections were terminated after 100 days by anthelmintic treatment, at which time faecal egg counts had fallen to low levels. Total serum IgE increased slowly from 20 days p.i. until anthelmintic treatment. The specific IgE response to T. colubriformis adult antigen peaked at 20-27 days p.i. before returning to near baseline levels. A further slight increase occurred between 56 and 100 days p.i. The animals were then divided equally into two groups. A first series of challenge infections consisting of either weekly 10,000 TcL3 infections (Group A) or a single 30,000 TcL3 infection (Group B) produced low faecal egg counts. Total and specific IgE to adult and L3-ES antigens increased rapidly over a 21-day period, then remained elevated irrespective of challenge regime. Termination of primary and the first challenge infections with anthelmintic resulted in a rapid decline in serum IgE responses but not other T. colubriformis-specific Ig responses. A second series of challenge infections consisting of repeated 10,000 (Group A) or 20,000 TcL3 infections (Group B) resulted in all IgE responses peaking within 7-8 days p.i. Marked softening of faeces coincided with peaks of specific and total IgE responses during challenge infections. The results of this study showed that infection of sheep with T. colubriformis leads to elevated levels of total and parasite-specific IgE in serum. IgE responses following challenge suggest involvement of this antibody isotype in protection from T. colubriformis infections.

Animals↗
PubMed1998

Defense style and family environment.

Prospective observations of the defense styles of normal individuals suggest that the quality of the childhood family environment may influence the maturity of defense styles used in adulthood. In this study, 106 female adolescent psychiatric patients completed the Defense Style Questionnaire, and the Family Environment Scale (FES). Positive family characteristics such as cohesion and expressiveness, as measured by the FES, were correlated with the report of Mature Defenses. Negative family characteristics such as conflict were correlated with the report of Immature Defenses. Similar although weaker correlations were found after controlling for the effects of depression and defensiveness on the self-report measures.

Adolescent↗
PubMed1998

Age differences in context integration in memory.

This research examined the role of contextual integration in memories of younger and older adults. In 2 experiments, recall of a target picture to a context picture cue was better when sentences were generated that integrated the picture pair and when the picture pairs were already related to each other. Age differences were smallest when sentences were generated for semantically related pairs. Older adults generated the same type sentences as younger adults, although they generated fewer integrations for unrelated pairs. In a 3rd experiment, younger adults could not differentiate between younger- and older-generated sentences from Experiment 1, and the sentences did not differentially affect recall performance. The results are discussed in terms of age differences in self-initiated processing when using context.

Adult↗
PubMed1998

RhoA-dependent phosphorylation and relocalization of ERM proteins into apical membrane/actin protrusions in fibroblasts.

The ERM proteins (ezrin, radixin, and moesin) are a group of band 4. 1-related proteins that are proposed to function as membrane/cytoskeletal linkers. Previous biochemical studies have implicated RhoA in regulating the association of ERM proteins with their membrane targets. However, the specific effect and mechanism of action of this regulation is unclear. We show that lysophosphatidic acid stimulation of serum-starved NIH3T3 cells resulted in relocalization of radixin into apical membrane/actin protrusions, which was blocked by inactivation of Rho by C3 transferase. An activated allele of RhoA, but not Rac or CDC42Hs, was sufficient to induce apical membrane/actin protrusions and localize radixin or moesin into these structures in both Rat1 and NIH3T3 cells. Lysophosphatidic acid treatment led to phosphorylation of radixin preceding its redistribution into apical protrusions. Significantly, cotransfection of RhoAV14 or C3 transferase with radixin and moesin revealed that RhoA activity is necessary and sufficient for their phosphorylation. These findings reveal a novel function of RhoA in reorganizing the apical actin cytoskeleton and suggest that this function may be mediated through phosphorylation of ERM proteins.

3T3 Cells↗
PubMed1998

Soluble L-selectin concentration in bronchoalveolar lavage fluid obtained from infants who develop chronic lung disease of prematurity.

AIMS: To explore the changes in neutrophil adhesion molecule expression and release into bronchoalveolar lavage fluid (BAL) obtained from infants who developed chronic lung disease (CLD). METHODS: BAL fluid was obtained from 37 infants: 18 (median gestation 26 weeks, birthweight 835 g) who developed CLD, 12 (29 weeks, 1345 g) with respiratory distress syndrome (RDS) and seven control infants (33 weeks, 2190 g). RESULTS: Soluble L-selectin (sL-selectin) in BAL fluid from the CLD and non-CLD groups was similar immediately after birth, but in infants who subsequently developed CLD, sL-selectin remained persistently increased (at day 7: CLD 42.6 vs RDS 6.0 ng/ml, p < 0.05; CLD vs controls 1.5 ng/ml; p < 0.05). CD11b/CD18 expression on neutrophils obtained by BAL increased with time to reach a maximum at 17 days of age in infants who developed CLD. CONCLUSIONS: These results suggest that leucocyte traffic persists in infants who develop CLD and may have an important part to play in the pathogenesis of CLD.

Analysis of Variance↗
PubMed1998

Pulmonary tuberculosis in Harare, Zimbabwe: analysis by spoligotyping.

BACKGROUND: Over the last 10 years there has been a fourfold increase in cases of tuberculosis in Harare, Zimbabwe. The use of molecular epidemiology to understand tuberculosis transmission in this epidemic has been hampered by the availability of suitable culture facilities. A study was therefore undertaken to explore the potential of spoligotyping, a polymerase chain reaction based technique that does not require tuberculosis culture. METHODS: Adults attending a chest clinic with clinical or radiological pulmonary tuberculosis and one smear positive sputum were enrolled over one month. Demographic, socioeconomic, and clinical data were gathered using a standardised questionnaire. Molecular fingerprinting of genomic DNA recovered from sputum was performed by spoligotyping. RESULTS: Sixty one subjects (median age 28 years (range 18-73); 61% men) were recruited and 57 provided adequate sputum samples. Recent rural-urban migration or immigration was not common; 40% of subjects lived in crowded living conditions. DNA suitable for spoligotyping was recovered from 28 patients and 20 different genotypes of Mycobacterium tuberculosis were identified. Fifteen patients were infected with an M tuberculosis strain shared by one or more individuals. Patients infected with a shared spoligotype were not closely linked geographically within Harare, but were more likely to live in overcrowded conditions (69% versus 23%; odds ratio 6.85 (95% CI 1.2 to 47), p = 0.026). Analysis of the patients' original rural family homes revealed two geographically related spoligotype clusters. CONCLUSIONS: Spoligotyping may yield valuable molecular typing information in populations where tuberculosis culture is not available. This novel technique requires further development and evaluation in larger epidemiological studies.

Adolescent↗
PubMed1998

"The spotlight initiative": evidence from oral and maxillofacial surgery.

In 1996 Strathclyde Police launched a campaign in order to reduce crime, especially violent crime in the region. Surgical data have been previously suggested as a more accurate reflection of violent activity than police statistics. Whilst police figures record success in reducing serious violent crime during this initiative, there was a slight increase in facial fractures resulting from assault in public places in the same period although this increase was not significant at the p < 0.05 level.

Female↗
PubMed1998

A descriptive study of the demography, symptomology, management and outcome of the first 300 patients admitted to an independent hospice in Singapore.

The aims of this study were: 1) to describe the demography, symptomology, investigations conducted, non-pharmacological interventions and outcome of patients admitted to an inpatient hospice and 2) to identify the nursing and medical needs of terminally ill patients. Case-notes of the first 300 patients admitted to Dover Park Hospice were studied retrospectively. There were 159 men and 141 women making up 325 admissions. The racial distribution was: Chinese 95.0%, Malays 3.0%, Indians 1.3% and Others 0.6%. Two-thirds of the men (64.2%) had spouses while 44.7% of the women were widowed. The mean age was 64.7 years. The 3 most common cancers were lung (21.7%), colorectal (14.6%) and hepatobiliary (12.5%). A proportion of patients (39.5%) were not known to have any metastases. Most patients were referred from hospitals and the home-care based Hospice Care Association. The commonest reason for admission was for "terminal care" (57.2%). At admission, only 38% of the patients were aware of their diagnoses and prognosis while 30% did not know either. The average length of stay was 25 days with 7.7% of patients having more than one admission. The most common symptoms were pain, anorexia, breathlessness, insomnia, constipation and dry skin. Non-pharmacological interventions ranged from manual evacuation of the rectum to transfers to tertiary hospitals for surgery and other more invasive interventions. Many patients also attended day-care activities (23.1%). Outcome of the 325 admissions were as follows: went home 20%, died in the hospice 73.2%, went home to die 4.9% and others 1.8%.

Adult↗
PubMed1998

Localization and functional domains of the neurofibromatosis type II tumor suppressor, merlin.

The neurofibromatosis type II (NF2) tumor suppressor gene is inactivated in the development of familial and sporadic schwannomas and meningiomas. The encoded protein, merlin, is closely related to ezrin, radixin, and moesin, which are members of the band 4.1 family of membrane/cytoskeletal linker proteins. We have examined the localization and effects of overexpressing epitope-tagged full-length isoforms of merlin as well as amino- and carboxyl-terminal truncations. The full-length and the amino-terminal domain of merlin localize to cortical actin, particularly areas of dynamic actin rearrangements such as membrane ruffles. Furthermore, overexpression of the carboxyl half of merlin induces cell death in NIH3T3 cells. The effect is splice-form specific and is not observed in the context of the full-length molecule. Thus, as has been described for the erzin, radixin, and moesin proteins, the activities of the carboxyl-terminal domain of merlin may be suppressed by the amino-terminal domain.

3T3 Cells↗
PubMed1998

Diagnosis and management of tuberculosis.

Traditional laboratory methods used in the diagnosis of Mycobacterium tuberculosis are hindered by the organism being fastidiously slow growing. This has previously meant that species identification and drug sensitivity testing could take several weeks. New molecular biological techniques, which can be applied to both clinical samples and cultured isolates, have accelerated this diagnostic process to a number of days. The molecular biological methods used to identify M. tuberculosis and allow rapid drug susceptibility testing are reviewed. Novel molecular strain typing ("fingerprinting") techniques to discriminate between different isolates are discussed. The impact of these new methods on management is also reviewed.

DNA Fingerprinting↗
PubMed1997

Differential responses to challenge with live and dead Mycobacterium bovis Bacillus Calmette-Guérin.

Bacillus Calmette-Guérin (BCG) vaccination has been shown to protect against challenge with virulent Mycobacterium tuberculosis in a range of experimental animal models: in each case, protective efficacy requires vaccination with live bacteria. With the goal of moving to a new generation of safer, nonliving vaccines, efforts have been made to identify the factors that determine the efficacy of live vaccination. We show that injection of live, but not dead, BCG induces localized swelling in the mouse footpad model. Live and dead bacteria induce similar responses during the first week after vaccination as determined by immunohistochemical analysis of the site of injection and of the draining lymph node. The subsequent differential response is characterized by migration of acid-fast bacilli to the draining lymph node in the case of the live vaccine. This is accompanied by an increase in mononuclear cells in the lymph node and by expression of inducible nitric oxide synthase (iNOS) both in the lymph node and at the site of injection. The ability of the bacteria to migrate to the lymph node may be an important element in the efficacy of live BCG vaccination.

Animals↗
PubMed1997

Quantification of total sheep IgE concentration using anti-ovine IgE monoclonal antibodies in an enzyme immunoassay.

Monoclonal antibodies (mAbs) which recognize separate epitopes on ovine immunoglobulin E (IgE) have been used to develop a non-competitive antibody sandwich enzyme immunoassay (EIA) for quantitating ovine IgE. Purified anti-IgE mAb (YD3) coated onto polystyrene microtitre plates was used to capture IgE in serum samples. Biotinylated anti-IgE mAb (XB6) followed by streptavidin conjugated with horseradish peroxidase were used to detect captured IgE. Tetramethylbenzidine and H2O2 were used as enzyme substrate. A reference serum was prepared by pooling sheep sera containing elevated IgE levels. This reference serum was assigned a value of 100 units ml-1 and used to prepare standard curves for the EIA. The linear region of log-log transformed standard curve data covered a range of 0.05-0.8 units ml-1. The equation of a linear regression line fitted to this curve was used to determine sample concentrations. Using purified IgE, 1 unit of reference serum was equivalent to 0.86 micrograms ml-1 IgE. Maximum intra- and inter-assay coefficients of variation for the EIA were 4.6% and 9.7%, respectively. Subjecting serum samples to 15 freeze/thaw cycles, storage at room temperature for 16 days or incubation at 37 degrees C for 8 h resulted in minimal loss of IgE detection. Incubation of serum at 56 degrees C resulted in rapid reduction in detection of IgE by the EIA. The assay was used to determine IgE levels in adult sheep monospecifically infected with weekly doses of the nematode Trichostrongylus axei. Serum IgE levels increased from 9 to 16 days following first infection and reached maximum levels by days 35-58. Serum IgE responses closely followed IgE positive cell responses in the abomasal mucosa.

Animals↗
PubMed1997

Thalidomide reduces tumour necrosis factor-alpha production by human alveolar macrophages.

Overexuberant production of tumour necrosis factor-alpha (TNF-alpha) by macrophages and other cells is thought to contribute to the development of permanent lung damage in many inflammatory conditions. There is a need for an agent, without the side-effects of corticosteroids, which can reduce the production of TNF-alpha by macrophages activated by disease. This study evaluated the effect of thalidomide on lipopolysaccharide (LPS)-induced TNF-alpha production by human alveolar macrophages obtained from patients with tuberculosis and a group of other diseases associated with macrophage activation. Alveolar macrophages obtained by bronchoalveolar lavage from 31 patients (tuberculosis = 12, sarcoidosis = 3, lung cancer = 5, chronic bronchitis = 5, pneumonia = 6) were stimulated with LPS alone or LPS in combination with either thalidomide or dexamethasone. Cell-associated TNF-alpha, as measured by immunochemistry, and TNF-alpha released by macrophages, as assessed by ELISA, were markedly increased when cells were incubated with LPS (P < 0.05), and both were decreased following addition of thalidomide (P < 0.05) or dexamethasone (P < 0.05) to amounts similar to those observed when macrophages were incubated with medium alone. Similarly, TNF-alpha mRNA as measured by in situ hybridization was increased following incubation with LPS (P < 0.05), but this increase was prevented by addition of thalidomide (P < 0.05) or dexamethasone (P < 0.05). The ability of thalidomide to reduce LPS-induced TNF-alpha production by alveolar macrophages was the same when cells from patients with tuberculosis (a disease associated with TNF-alpha production) and cells from patients with the other conditions were compared. The ability of thalidomide to reduce TNF-alpha production by human alveolar macrophages from patients with active lung disease suggests that thalidomide and its analogues may have potential as drugs to reduce TNF-alpha production in disease.

Adult↗
PubMed1997

Interleukin-10- and corticosteroid-induced reduction in type I procollagen in a human ex vivo scar culture.

Fibroblasts act as the effector cells of the fibrotic response via production of collagen. In an attempt to understand the regulation of fibroblasts from areas of active human tissue fibrosis, we have developed an ex vivo model in which biopsies of scars from patients 6 weeks post thoracotomy were cultured. This model has been used to investigate whether interleukin-10 (IL-10) and triamcinolone acetonide modulate the expression of type I procollagen mRNA and protein. In situ hybridization and a quantitative competitive RT-PCR were used to measure type I procollagen mRNA. Type I procollagen protein was evaluated by immunochemistry. Viability of biopsies in culture using 3H-uridine incorporation into RNA was observed to be > 80% for at least 96 hours. Following addition of either IL-10 or triamcinolone acetonide there was a modest but significant decrease (P < 0.05) in type I procollagen mRNA expression. Similarly, each agent added individually to biopsies reduced the proportion of cells staining positively for type I procollagen when compared to biopsies treated with medium alone (P < 0.05). These results extend in vitro data that IL-10 and corticosteroids down-regulate collagen synthesis in skin fibroblast cell lines and suggest that this ex vivo model may offer a closer approximation to the post-operative scarring process when testing new therapeutic agents for reducing an over-exuberent fibrotic response.

Administration, Topical↗