Biomedical subjects

M Anderson

Publications and source records attributed to M Anderson.

At least 199 records · Page 11Linked to original sources

PubMed1996

Monocyte chemoattractant protein-1: receptor interactions and calcium signaling mechanisms.

Monocyte chemoattractant protein-1 (MCP-1) is a member of the Cys-Cys chemokine family. Two related MCP-1 receptors have been identified (CC-CKR2A and CC-CKR2B), although the precise kinetics of ligand binding and calcium signaling of these receptors has yet to be investigated. To examine this more closely, the human MCP-1 receptors were cloned and expressed in Chinese hamster ovary (CHO) cells. Membranes prepared from cells expressing CC-CKR2B bind MCP-1 selectively and with high affinity (Kd = 120 pM). MCP-1 stimulation of recombinant CHO cells expressing CC-CKR2B induces a rapid increase in intracellular Ca2+ through both receptor-operated Ca2+ channels and mobilization of Ca2+ from intracellular stores, and leads to a rapid temperature-dependent internalization of the ligand/receptor complexes. In contrast, recombinant CHO cells expressing CC-CKR2A, and membranes prepared from these cells, fail to bind detectable levels of MCP-1. However, MCP-1 stimulation of cells expressing CC-CKR2A induces a small but significant increase in intracellular Ca2+. Repeated stimulation of these cells with MCP-1 leads to a potentiation of the response to a level comparable to that seen in cells expressing CC-CKR2B. These observations suggest that the levels of cell surface CC-CKR2A are controlled by novel mechanisms.

Animals↗

PubMed1996

Differential expression of normal and mutant Huntington's disease gene alleles.

Huntingtin expression was examined by Western blot and immunoprecipitation studies of lymphoblastoid cell lines from Huntington's disease (HD) homozygotes, heterozygotes, and a phenotypically normal individual with a t(4p16.3;12p13.3) breakpoint in the HD gene. The latter produced a reduced level of normal huntingtin without evidence of an altered protein, indicating that simple loss of huntingtin activity does not cause HD. In juvenile onset HD heterozygotes, NH2- and COOH-terminal antisera revealed reduced relative expression from the mutant allele. Pulse-chase studies indicated that huntingtin is a stable protein whose differential allelic expression is not due to destabilization of the mutant isoform. No stable breakdown products specific to mutant huntingtin were detected in either HD homozygotes or heterozygotes. These data are consistent with HD involving either a gain of function or a dominant negative loss of function that operates within severe constraints and suggest that in either case the pathogenic process is usually saturated by the amount of abnormal huntingtin produced from a single mutant allele.

Adult↗

PubMed1996

High level expression of human MCP-1 using the LCR/MEL expression system.

We have expressed human monocyte chemoattractant protein-1 (hMCP-1) in preerythroid mouse erythroleukemia (MEL) C88 cells using the locus control region/MEL expression system and studied the biological activity of the purified protein in a range of in vitro experimental systems. The recombinant hMCP-1 is expressed at high levels (approximately 10 mg/liter) in this system and is modified in a manner which is very similar to native hMCP-1. We have developed a simple high-yielding two-step purification route employing dye ligand and ion exchange chromatographies which enables us to separate glycosylated and unglycosylated hMCP-1. The purified glycosylated and unglycosylated forms of hMCP-1 have equivalent biological activities in all of the assay systems tested.

Animals↗

PubMed1996

Assessing health service needs: tools for health planning.

As fiscal pressures mount, health-planning and decision-making at smaller geographics scales must be more effective. Involving local constituents in needs assessments, it is believed, would lead to better identification and serving of regional demands and needs for health services. This article examines needs assessment as a tool to determine a community's service needs and establish priorities for the creation of programs. Various approaches used in needs assessments are described, including survey methods, structured groups and geographic information systems.

Canada↗

PubMed1996

Characterization of in-vitro spermicidal activity of chelating agent against human sperm.

The effect of ethylenediaminetetraacetic acid (EDTA), a cationic chelating agent, on sperm motility and sperm penetration through cervical mucus was evaluated. EDTA exerted a relatively mild dose-dependent effect on sperm motility. Total loss of sperm motility (EC100) was achieved at a concentration of about 5.0 mg/mL of EDTA, which is much greater than the 200 micrograms/mL concentration of Nonoxynol-9 (N-9). EDTA salts, such as EDTA-Na2 and EDTA-Na4, showed weak spermicidal activity, while EDTA-K2 and EDTA-Ca had no spermicidal activity at concentrations up to 5.0 mg/mL. EDTA appeared to decrease the in vitro percentage of motile sperm as a function of exposure time. EDTA completely impeded the penetration of sperm into cervical mucus at a concentration much lower than that for 100% inhibition of sperm motility in semen. In the presence of 500-3200 micrograms/mL extra calcium, the first-order rate constant for sperm immobilization, which was derived from the slopes of a relative sperm motility curve, was reduced by 38.9--55.6% of the control and was inversely proportional to calcium concentration. After exposure to EDTA, the calcium ion concentration in semen was reduced as a function of EDTA concentration, which yielded a linear reduction of sperm motility. A decrease of approximately 65% in calcium ion concentration in semen seemed to be the threshold at which total loss of sperm motility occurred. Calcium ion was shown to play an essential role in regulating sperm molitility in semen, and EDTA was demonstrated to exert spermicidal activity by modulating calcium ion concentration in semen.

Animals↗

PubMed1996

The pursuit of excellence in nursing care: what does it mean?

This study explores the meaning of excellence in nursing care held by nurses. Qualitative data were collected from 156 undergraduate and postgraduate nurses by means of an open-ended questionnaire. Respondents were asked to reflect on practice which enabled a clear understanding of the meanings given to excellence in nursing care. In addition, details of their nursing background, level of nursing experience, and demographics were sought. Responses were content-analysed for themes by three coders. Four major themes emerged: (1) professionalism, (2) holistic care, (3) practice, (4) humanism. The fourth theme comprised three sub-themes: (a) enabling personal qualities, (b) nurse patient relationships, and (c) nurse-health team relationships. Responses revealed that professionalism constituted an all-encompassing theme subsuming all others. Findings suggested that the client is the central focus of excellent nursing care at all times. According to these respondents, nurses who deliver excellent nursing care implement nursing in a professional and competent manner, demonstrate a holistic approach to caring, possess certain personal qualities which enhance practice, and relate to patients, families, peers, hospital administrators and community members in a competent, cooperative manner. An important aspect of this study is the differential quality of responses provided by respondents, who were students enrolled in a nursing degree programme compared to respondents who were state-registered nurses and concurrently undertaking higher degree studies. The final result is suggestive of the stages of transition through which nurses pass in their quest for excellence.

Adolescent↗

PubMed1996

NMR studies of Pi-containing extracellular and cytoplasmic compartments in brain.

The inorganic phosphate (Pi) NMR peak in brain has an irregular shape, which suggests that it represents more than a single homogeneous pool of Pi. To test the ability of the Marquardt-Levenberg (M-L) nonlinear curve fit algorithm software (Peak-Fit) to separate multiple peaks, locate peak centers, and estimate peak heights, we studied simulated Pi spectra with defined peak centers, areas, and signal-to-noise (S/N) ratios ranging from infinity to 5.8. As the S/N ratio decreased below 15, the M-L algorithm located peak centers accurately when they were detected; however, small peaks tended to grow smaller and disappear, whereas the amplitudes of larger peaks increased. We developed an in vitro three-compartment model containing a mixture of Pi buffer, phosphocreatine, phosphate diester, and phosphate monoester (PME), portions of which were adjusted to three different pHs before addition of agar. Weighed samples of each buffered gel together with phospholipid extract and bone chips were placed in an NMR tube and covered with mineral oil. Following baseline correction, it was possible to separate the Pi peaks arising from the three compartments with different pH values if each peak made up 10-35% of total Pi area. In vivo, we identified the plasma compartment by intraarterial infusion of Pi. It was assumed that intracellular compartments contained high-energy phosphates and took up glucose. Based on these assumptions we subjected the brains to complete ischemia and observed that Pi compartments at pH 6.82, 6.92, 7.03, and 7.13 increased markedly in amplitude. If the brain cells took up and phosphorylated 2-deoxyglucose (2-DG), 2-DG-6-phosphate (2-DG-6-P) would appear in the PME portion of the spectrum ionized according to pH. Four 2-DG-6-P peaks with calculated pH values of 6.86, 6.94, 7.04, and 7.15 did appear in the spectrum, thereby confirming that the four larger Pi peaks represented intracellular spaces.

Animals↗

PubMed1996

Resistance to Activated Protein C: Comparison of Three Different PCR Methods for Detection FV R506Q.

Background: Resistance to activated protein C(APC) is the most prevalent identifiable risk factor for inherited thrombophilia. Over 90% of APC resistance results from a single point mutation in the Factor V gene. The mutation, termed FV R506Q of FV Leiden, predicts an abnormal Factor Va protein in which arginine, at amino acid position 506, is replaced by glutamine, rendering Factor Va resistant to proteolytic inactivation by APC, thus establishing a life long hypercoagulable state. The current study compared three different polymerase chain reaction (PCR)-based approaches for the detection of FV R506Q. Methods and Results: Sixty-seven patient blood samples were genotyped by (1) analyzing for loss of a Mnl I recognition site, an acquired restriction-fragment-length polymorphism (RFLP) due to FV R506Q; (2) primer-engineered RFLP wherein the presence of FV R506Q results in generation of a novel Nla III recognition site; and (3) allele-specific PCR. Sixty-five of 67 patient samples yielded concordant genotype results by all three PCR methods. Of the remaining 2 of the 67 patients, a "nondiagnostic" result was obtained for either allele-specific PCR or primer-engineered RFLP. Conclusions: A comparative analysis of 67 patient samples demonstrated that primer engineered RFLP and allele-specific PCR offer feasible alternative or confirmatory testing approaches to Mnl I RFLP for the detection of FV R506Q. A high degree of diagnostic concordance was observed for all three methods, and no false positive or negative results were observed with the Mnl I RFLP technique.

Journal Article↗

PubMed1996

Metazoan rDNA enhancer acts by making more genes transcriptionally active.

Enhancers could, in principle, function by increasing the rate of reinitiation on individual adjacent active promoters or by increasing the probability that an adjacent promoter is activated for transcription. We have addressed this issue for the repetitive metazoan rDNA enhancer by microinjecting Xenopus oocytes with enhancer-less and enhancer-bearing genes and determining by EM the frequency that each gene type forms active transcription units and their transcript density. We use conditions where transcription requires the normal rDNA promoter and is stimulated 30-50-fold by the enhancer. (In contrast, at saturating template conditions as used in previous EM studies, an aberrant mode of transcription is activated that is not affected by the rDNA enhancer or by the generally recognized rDNA promoter). The active transcription units on enhancer-less genes are found to be as densely packed with nascent transcripts and polymerases as those on enhancer-bearing genes and on the endogenous rRNA genes. Significantly, the enhancer-bearing genes are approximately 30-50-fold more likely to form such active transcription units than enhancer-less genes, consistent with their amounts of transcript. Complementary studies confirm that the enhancer does not affect elongation rate, the stability of the transcription complex, or transcript half-life. These data demonstrate that the repetitive metazoan rDNA enhancer causes more genes to be actively transcribed and does not alter the reinitiation rate on individual active genes.

Animals↗

PubMed1996

Focal upper limb demyelinating neuropathy.

Observations are presented on nine selected patients with chronic upper limb demyelinating neuropathy to illustrate the range of manifestations that may be observed. In three, the involvement was purely motor, in five, mixed motor and sensory and, in one, virtually purely sensory; in seven the symptoms were unilateral and in two bilateral. The presence of reduced nerve conduction velocity and conduction block and the response to treatment in seven of the cases indicate that they represented examples of chronic inflammatory demyelinating polyneuropathy (CIDP) with focal involvement. This was confirmed by nerve biopsy in two cases. The presentation in one patient was accompanied by forearm swelling initially suspected of being a tumour but shown to be due to muscle hypertrophy. This was probably the consequence of recurrent muscle cramps and fasciculation and possibly neuromyotonia. The patient with predominant sensory involvement restricted to the upper limbs demonstrates that sensory CIDP can present focally. In one patient with monomelic motor and sensory involvement, nerve biopsy showed multifocal areas of hypertrophic demyelinating neuropathy distally in the ulnar nerve without inflammatory infiltration. This patient failed to respond to therapy. Response in the others was satisfactory, although one patient with a monomelic motor neuropathy showed a severe deterioration after being given corticosteroids; he subsequently improved with intravenous human immunoglobulin therapy.

Adolescent↗

PubMed1996

Spectral sensitivity in the eyes of male and female Lutzomyia longipalpis sandflies.

Using electroretinogram recordings, the response of Lutzomyia longipalpis sandfly eyes to a range of wavelengths of light was measured, and spectral sensitivity determined. The eyes of both male and female adult sandflies were found to respond maximally to light in the ultraviolet region (at 340 nm) with a secondary peak in the blue-green-yellow region at 520 nm for females and 546 nm for males. The Mann-Whitney U test showed no significant differences between males and females at corresponding wavelengths.

Adaptation, Physiological↗

PubMed1996

Influence of surfactants on pyrene desorption and degradation in soils.

Four surfactants were tested at five concentrations to determine their abilities to solubilize soil-adsorbed pyrene. Inoculation with pyrene degraders in the presence of the surfactant Witconol SN70 was the most effective treatment for pyrene mineralization (46 to 80%) under unsaturated conditions, but the surfactant inhibited the effectiveness of these inoculants in soil slurries.

Journal Article↗

PubMed1996

Increasing incidence of tuberculosis in the young and the elderly in Scotland.

BACKGROUND: Since 1987 there has been an arrest in the previously established decline of tuberculosis notifications in Scotland. A study was undertaken to determine whether age contributed to this phenomenon. METHODS: Notifications of tuberculosis in Scotland were quantified by year and age group for the years 1981-92 from national statistics supplied by the Information and Statistics Division. Population data were obtained from the 1981 and 1991 national censuses. RESULTS: Age group analysis of pulmonary tuberculosis notifications showed that, in the 0-14 age group, incidence (per 10(5) population) decreased from 7.4 in 1981 to 2.6 in 1987, rising by an estimated 12.6% per annum to 3.7 in 1992. In the 65+ age group incidence declined from 30.1 in 1981 to 17.3 in 1988, and rose by an estimated 4.1% per annum to 22.2 in 1992. In the age groups 15-44 and 45-64 a continuous decrease in notification rate was seen over the period of the study. CONCLUSIONS: The plateauing of the incidence of tuberculosis in Scotland is associated with significant increases since 1987 of tuberculosis in the young and elderly. Contributions from ethnic minorities and those infected with HIV are negligible. An ageing population over the decade, with the highest tuberculosis rates seen in the older age group, may explain these findings.

Adolescent↗

PubMed1996

Tracheobronchial deposition and clearance in small airways in asthmatic subjects.

Asthma tends to impair mucociliary clearance, as assessed from measurements in large airways. However, very little is known about clearance in the smallest airways of the tracheobronchial region. Deposition and clearance was estimated in 11 subjects with stable asymptomatic asthma and 10 healthy subjects after inhalation of 6 microns (aerodynamic diameter) monodisperse Teflon particles labelled with 111In. The particles were inhaled at an extremely slow flow, 0.05 L.s-1. Theoretical calculations and experimental data in healthy subjects using this slow flow support an enhanced deposition in the tracheobronchial region, in particular in the small ciliated airways (bronchioles). Lung retention was measured at 0, 24, 48 and 72 h. Clearance was significant every 24 h both for asthmatic and healthy subjects, with similar fractions of retained particles at all time-points. The fractions of tracheobronchially-deposited particles were on average 41 and 47% for asthmatic and healthy subjects, respectively, as compared to a maximal deposition of 30% using a normal inhalation flow (0.5 L.s-1). No significant correlation was found between lung retention and lung function, either in asthmatics or in healthy subjects. Our results indicate that particles clear equally well from small ciliated airways in asthmatic and healthy subjects, maybe as a consequence of an optimal asthma therapy. Furthermore, our results show that it is possible to enhance tracheobronchial deposition both in healthy and asthmatic subjects, i.e. practically independent of airway dimensions, by inhaling rather large aerosol particles extremely slowly. This may be a useful therapeutic approach.

Administration, Inhalation↗

PubMed1996

Oropharyngeal deposition of 3.5 microns particles inhaled through an elongated mouthpiece.

We previously studied the deposition of inhaled particles in the oropharynx of asthmatic patients, and found that a pharyngeal narrowing during inhalation seems to be one reason for high oropharyngeal deposition. In the present study, we investigated whether by-passing a larger part of the oral cavity by using an elongated mouthpiece would reduce deposition in the oropharynx, and increase deposition in the lungs. Deposition in the oropharynx and in the lungs was estimated in nine patients with obstructive airway diseases. In earlier investigations, three of these patients had repeatedly shown extremely high oropharyngeal deposition (> 70%). In the present study, the patients inhaled 3.5 microns (aerodynamic diameter) radiolabelled Teflon particles at 0.5 L.s-1, with and without an individually adapted elongated mouthpiece. Radioactivity was measured using a profile scanner. On average, oropharyngeal deposition was 27% (range 12-45%) and 30% (range 11-77%) of the total amount of particles deposited in the body, with and without elongated mouthpiece, respectively. There was no significant difference between these values (p > 0.05), nor between the values of lung deposition. However, oropharyngeal deposition was markedly reduced, with a corresponding increase in lung deposition, by the elongated mouthpiece in the one and only patient who still showed extremely high oropharyngeal deposition (> 70%). Our study shows that lengthening of the mouthpiece is not sufficient to reduce average deposition of aerosol particles in the oropharynx in patients with comparatively normal deposition values. This result, however, does not exclude a beneficial effect in patients with extremely high oropharyngeal deposition.

Administration, Inhalation↗

PubMed1996

Examination of p53 alterations and cytokeratin expression in sputa collected from patients prior to histological diagnosis of squamous cell carcinoma.

Mutations in the p53 gene are detected in greater than 50% of squamous cell carcinomas of the lung and to a lesser extent in adenocarcinomas. The p53 protein is also overexpressed in a relatively high percentage of preinvasive lesions of the bronchial epithelium. However, unlike tumor tissue, immunoreactivity does not necessarily imply that cells in preinvasive lesions carry a mutant p53 allele. In some cases, overexpression may result from a cellular checkpoint reaction to a toxic or mutagenic substance such as exposure to tobacco smoke. In any case, p53 overexpression in preinvasive lesions may serve as a biomarker for high risk assessment of lung cancer and other tumors in the aerodigestive tract. A study was designed to retrospectively analyze p53 overexpression in cells from sputum samples collected prior to histological tumor diagnosis. The rationale was based on the observation that both preinvasive and tumor cells from the bronchial epithelium are exfoliated into the airways and can be detected based on morphology in sputa. Two sets of cases were chosen: 1) patients whose first primary tumor was a squamous cell carcinoma containing a mutant p53 allele with overexpression observed in most of the tumor cells; and 2) patients whose squamous cell tumor did not contain a mutant p53 allele. Cells which stained positive for p53 expression were observed in sputum samples collected from all six patients whose tumors were positive for a mutant p53 allele. Also p53 positive cells were detected on sputum slides for two of the five cases where the tumor DNA did not contain a mutation and/or tumor cells which overexpress p53 were not detected in tissue sections. Although cells which stained positive for p53 were present in sputum from patients whose tumors contained a missense mutation, the presence of p53 overexpression was not specific for tumors which contain an altered p53 allele since overexpression was detected in sputum cells from patients whose tumor DNA did not contain a p53 mutation and/or tumor cells which stained positive for p53 were not observed in tissue sections. However, the p53 positive cells in sputa collected from the latter group of patients could have been exfoliated from other lesions which contained a mutant p53 allele. The accumulation of p53 in some sputum cells was concomitant with expression of simple epithelial type cytokeratins (CK) 8 and 18 or at least one of the other cytokeratins detected by a broad spectrum (PAN) CK antibody mixture. These data imply that most of the sputum cells which overexpress p53 are epithelial cells. Moreover, our results are consistent, at least in part, with other observations that cells which overexpress p53 in dyplasias and hyperplasias express CK 8, 18. We will continue to explore the possibility that expression of cytokeratins 8, 18 and/or other cytokeratins in conjunction with p53 overexpression and/or morphological criteria could define a new class of atypical cells which are predisposed to cancer development.

Alleles↗

PubMed1995

Purification and optimization of functional reconstitution on the surface of leukemic cell lines of GPI-anchored Fc gamma receptor III.

Purified glycosyl phosphatidyl inositol (GPI)-anchored cell surface proteins can be reincorporated spontaneously into the cell membrane by incubating the cells with these proteins. This unique property provides a novel way of introducing cell surface receptors on live cell membranes without the use of gene transfection. Since any classical transmembrane cell surface protein can be converted to a GPI anchored protein by recombinant techniques, this method provides a means of studying ectodomain associated receptor functions on various cell types. Moreover, in some circumstances, it can be used to correct deficient cellular functions resulting from lack of cell surface protein expression. Using GPI-anchored Fc gamma receptor III (CD16B), a low affinity Fc gamma receptor, we have systematically studied the optimal conditions for reconstitution of a functional receptor on nucleated cells. CD16B is purified to homogeneity from neutrophil lysates by single step immunoaffinity chromatography. The purified CD16B is functionally active as evidenced by its ability to bind IgG opsonized erythrocytes. CD16B incorporation on nucleated cells is temperature dependent with an optimum of 37 degrees C. The level of expression of incorporated CD16B is also depend on the concentration of CD16B available and the duration of incubation. The incorporated CD16B retains its ability to bind ligand and also mediates endocytosis of the bound ligand. In summary, our results demonstrate that purified, functionally active GPI-anchored receptors can be expressed on desired cells in a controlled manner and retain some functional properties.

Animals↗

PubMed1995

Human papillomavirus testing in primary cervical screening.

Several studies have examined the role of tests for human papillomavirus (HPV) in screening for cervical cancer but as yet the relevance is unclear. We looked at HPV testing for types 16, 18, 31, and 33 on material taken at the time of a cervical smear in 2009 eligible women having routine screening. Women with any degree of dyskaryosis or high levels of one of these HPV types were referred for colposcopy. 44% of the cervical intraepithelial neoplasia (CIN) lesions of grade 2/3 detected had negative cytology and were found only by HPV testing. A further 22% of the CIN 2/3 lesions were positive for HPV but showed only borderline or mild cytological changes. The positive predictive value of HPV testing was 42%, which was similar to that for moderate dyskaryosis. HPV types 16 and 31 were more sensitive and specific for CIN 2/3 than were types 18 or 33. However, 25% of the CIN 2/3 lesions were not detected by these four HPV tests. We suggest that HPV testing could usefully augment but not replace conventional cytology. These results should stimulate a much larger randomised trial to assess the impact of these improved CIN 2/3 detection rates on the subsequent incidence of invasive cancer.

Adult↗