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M Scott

Publications and source records attributed to M Scott.

At least 163 records · Page 9Linked to original sources
PubMed1996

Semi-automated ELISA-based detection system for verifying the authenticity of amplified t(14;18)-containing products.

PCR product sizing on ethidium bromide-stained gels, coupled with Southern transfer and hybridization with nonisotopic probes, is an effective way of detecting t(14;18)(q32;q21). We evaluated an alternative ELISA-based test for detecting amplified t(14;18) products. Digoxigenin (DIG)-labeled dUTP is incorporated in a standard PCR method for amplification of bcl-2 major breakpoint region (mbr) rearrangements. The product is hybridized to a specific biotinylated DNA probe internal to the mbr primer, placed in streptavidin-coated wells of a microtiter plate, and detected with a alkaline phosphatase-conjugated anti-DIG antibody and enzyme substrate (pNpp). The colorimetric product is quantitated by an automated optical density (O.D.) reader. We evaluated 13 mbr-positive follicular lymphomas (FL), five mbr-negative B-cell neoplasms (BCN), 16 reactive lymphoid hyperplasias (RLH), 14 cases of Hodgkin's disease (HD), and normal peripheral blood samples from 20 healthy volunteers. All samples were evaluated in duplicate on separate plates. Positive [t(14;18)-containing cell line] and negative [cell line without t(14;18); master mix only] controls, and a standard curve were included with each run. Numerical O.D. readings from the specific hybridization assays revealed differences between FL and the other categories. All FL had an O.D. reading at > 2.0. The vast majority of RLH, HD, BCN, and normal peripheral blood samples showed O.D. readings well below 2.0. Specifically, 13/16 RLH and all HD, BCN, and normal peripheral blood samples had an O.D. of < or = 0.6 in all runs. The three outliers, which were all < 2.0, may represent the low level detection of t(14;18)-containing cells in RLH similar to previous reports. Moreover, all but four RLH had O.D. readings above the background negative controls, suggesting that rare t(14;18)-containing cells may have been present in these samples, as well. Dilution studies estimate that this assay is capable of detecting 1 t(14;18)-containing cell in approximately 10(5) cells, a greater level of sensitivity than can be obtained with gel visualization alone. We conclude that this semi-automated, potentially quantifiable ELISA-based system is a useful, objective and reproducible alternative hybridization procedure for verifying PCR product specificity in this setting.

Chromosomes, Human, Pair 14↗
PubMed1996

Predictive value of preschool surveillance in detecting learning difficulties.

OBJECTIVES: The Hall report specified the early detection of mild to moderate learning difficulties as one aim of child health surveillance (CHS). This study examines the efficacy of preschool CHS in the early recognition of children with these disorders. DESIGN: A retrospective case-control study. SUBJECTS: All children (n = 408) with mild to moderate learning difficulties born between 1 July 1983 and 30 June 1984 and resident in North and West Belfast. CONTROLS: 2406 birth records and 150 full child health records controlled for age and geographical area. RESULTS: The prevalence of mild to moderate learning difficulties in North and West Belfast was 16%. Only 6% of children with learning difficulties were identified by the CHS in the preschool period, although the detection rate for children eventually requiring placement in schools for moderate learning difficulties was better. Coverage of the CHS ranged from 90% at the 2 year examination to 98% at the 4 year examination. Perinatal variables associated with learning difficulties after multiple logistic regression analysis were lower social class (odds ratio (OR) 3.9), prematurity < 35 weeks (OR 3.0), male sex (OR 1.6), and birth to an unmarried mother (OR 0.6). Independent preschool variables identified by the CHS were speech delay (OR 3.3), poor parenting skills (OR 4.0), behaviour problems (OR 2.8), enuresis (OR 2.4), poor visual acuity (OR 1.8), and otitis media with effusion (OR 1.4). A statistical model for the early detection of learning difficulties using these risk factors is unable to predict accurately the children who will develop mild to moderate learning difficulties. CONCLUSIONS: The CHS as it existed from 1983 to 1989 in North and West Belfast was poorly sensitive to the detection of mild to moderate learning difficulties despite excellent coverage. An accurate predictive model for learning difficulties could not be developed from the risk factors documented by the CHS.

Case-Control Studies↗
PubMed1996

Type I Glanzmann's thrombasthenia in a Great Pyrenees dog.

An 8-month-old female Great Pyrenees dog with chronic epistaxis and a history of gingival bleeding during shedding of deciduous teeth was evaluated for platelet function. Platelet morphology was normal at both the light and electron microscopic level. Platelet number and mean platelet volume were also normal. Platelet aggregation responses to adenosine diphosphate, collagen, platelet activating factor, and thrombin were markedly reduced, although shape change responses were normal. Clot retraction was markedly impaired. Monoclonal antibody (MoAb) Y2/51, a murine anti-human platelet beta 3 antibody that cross-reacts with canine platelet beta 3, and MoAb 5G11, a murine anti-dog platelet alpha IIb beta 3 antibody, bound minimally to affected dog platelets, as demonstrated by flow cytometry. Binding of MoAb Y2/51 was not detectable by immunoblot. MoAb CAP1, a murine anti-dog fibrinogen receptor-induced binding site antibody, failed to bind to affected dog platelets, as demonstrated by flow cytometry. A reduction in glycoproteins alpha IIb and beta 3 was demonstrated by two-dimensional protein electrophoresis. This is the first reported case of type I Glanzmann's thrombasthenia in the dog that closely resembles the clinical syndrome and the platelet morphology described in type I Glanzmann's thrombasthenia of human beings.

Animals↗
PubMed1996

Proto-oncogene expression in cAMP and TPA-mediated neuronal differentiation in a human retinal cell line KGLDMSM.

PURPOSE: A human retinal cell line, KGLDMSM, developed by SV-40T antigen gene transfection, is stable in culture for a long period, unlike the primary cells. The cell line shows some degree of morphological differentiation with limited extension of stublike neurites upon transfer to defined medium. In our effort to explore genes implicated in neuritic extension and neuronal differentiation seen in response to cAMP and TPA, we have analyzed time dependent induction of a variety of proto-oncogenes: c-myc, H-ras, c-ras, and c-fos. METHODS: Cells were adapted to grow in defined media and exposed to differentiation inducing agents cAMP, TPA, Retinoic Acid, and sodium butyrata. Cells were assessed for phenotypic changes and altered expression of proto-oncogenes as evaluated by Northern Blot analysis and immunocytochemistry. RESULTS: Exposure of the cells to cAMP and TPA induced dramatic changes, with 100% of the cells extending neuritic processes. However, other differentiation inducing agents such as retinoic acid and sodium butyrata failed to elicit any response. We report that agents that promote neuritic extension also induce expression of c-fos. Transcriptional activation of c-fos in response to cAMP (30 min) and TPA (1hr) is also accompanied by expression of fos gene product as evaluated by using fos antibody. No fos expression was seen in uninduced cells. CONCLUSION: In retinal cell line KGLDMSM, agents that enhance neuronal differentiation (cAMP, TPA) also induce c-fos expression. Expression of c-fos may be a necessary prerequisite in neuronal differentiation and the established retinal cell line offers an excellent cell model for dissecting the molecular events underlying neuronal differentiation.

Cell Differentiation↗
PubMed1996

Morphine suppresses the alloantigen-driven CTL response in a dose-dependent and naltrexone reversible manner.

Previous studies have shown morphine (50.0 mg/kg, s.c.) suppresses cytotoxic T lymphocyte (CTL) activity in alloimmunized mice. The present study was undertaken to assess the dose-dependent nature of the suppressive effect of subchronic morphine exposure on CTL activity in vivo. In alloimmunized ICR mice, morphine (10.0-100.0 mg/kg, s.c.) administered daily for 5 days significantly suppressed CTL activity ( > 50%) in a dose-dependent and naltrexone (10.0 mg/kg, s.c.)-reversible fashion. The morphine-treated mice showed tolerance to the drug after daily exposure over 5 days as determined by measuring tail flick latency during thermal application. CD4(+)- and CD8(+)-depletion studies showed that effector cells were predominately CD8+ and mediated cytolysis through a Ca(++)-dependent pathway. Splenocytes obtained from the morphine (56.0-100.0 mg/kg)-treated, alloimmunized mice produced significantly less (30-40%) interferon-gamma but not interleukin-2 or interleukin-10 after antigen stimulation but not concanavalin A stimulation. Furthermore, this effect was dose- and time-dependent. In addition, there was a modest decrease (10%) in the interferon-gamma transcript level from the morphine (56.0-100.0 mg/kg)-treated, alloimmunized mice compared with vehicle-treated, alloimmunized mice as determined by quantitative reverse transcription-polymerase chain reaction. However, there were no differences in the perforin transcript levels between morphine- and vehicle-treated mice. Collectively, these results suggest that subchronic morphine exposure suppresses CTL activity in tolerized, alloimmunized mice through a pathway that may peripherally involve interferon-gamma production.

Animals↗
PubMed1995

Prion propagation in mice expressing human and chimeric PrP transgenes implicates the interaction of cellular PrP with another protein.

Transgenic (Tg) mice expressing human (Hu) and chimeric prion protein (PrP) genes were inoculated with brain extracts from humans with inherited or sporadic prion disease to investigate the mechanism by which PrPC is transformed into PrPSc. Although Tg(HuPrP) mice expressed high levels of HuPrPC, they were resistant to human prions. They became susceptible to human prions upon ablation of the mouse (Mo) PrP gene. In contrast, mice expressing low levels of the chimeric transgene were susceptible to human prions and registered only a modest decrease in incubation times upon MoPrP gene disruption. These and other findings argue that a species-specific macromolecule, provisionally designated protein X, participates in prion formation. While the results demonstrate that PrPSc binds to PrPC in a region delimited by codons 96 to 167, they also suggest that PrPC binds protein X through residues near the C-terminus. Protein X might function as a molecular chaperone in the formation of PrPSc.

Animals↗
PubMed1995

Scrapie prions selectively modify the stress response in neuroblastoma cells.

The fundamental event underlying scrapie infection seems to be a conformational change in the prion protein. To investigate proteins that might feature in the conversion of the cellular prion protein (PrPC) into the scrapie isoform (PrPSc), we examined mouse neuroblastoma N2a cells for the expression and cellular distribution of heat shock proteins (Hsps), some of which function as molecular chaperones. In scrapie-infected N2a (ScN2a) cells, Hsp72 and Hsp28 were not induced by heat shock, sodium arsenite, or an amino acid analog, in contrast to uninfected control N2a cells, while other inducible Hsps were increased by these treatments. Following heat shock of the N2a cells, constitutively expressed Hsp73 was translocated from the cytoplasm into the nucleus and nucleolus. In contrast, the distribution of Hsp73 in ScN2a cells was not altered by heat shock; the discrete cytoplasmic structures containing Hsp73 were largely resistant to detergent extraction. These alterations in the expression and subcellular translocation of specific Hsps in ScN2a cells may reflect the cellular response to the accumulation of PrPSc. Whether any of these Hsps feature in the conversion of PrPC into PrPSc or the pathogenesis of prion diseases remains to be established.

Animals↗
PubMed1995

CD5-expressing B-cell non-Hodgkin's lymphomas with bcl-1 gene rearrangement have a relatively homogeneous immunophenotype and are associated with an overall poor prognosis.

Mantle cell lymphomas (MCLs) are typically CD5-expressing B-cell non-Hodgkin's lymphomas (NHLs) that frequently harbor the chromosomal translocation t(11;14) or bcl-1 gene rearrangements. Insufficient data are available on the biologic features and clinical behavior of rigorously characterized MCL. As these NHLs have been reported to exhibit various histologic and cytologic expressions, and in order to avoid using somewhat arbitrary and subjective morphologic definitions, we chose to study cases of MCL selected on more objective grounds. Specifically, 15 samples (from 14 patients) of CD5-expressing B-cell NHLs with detectable bcl-1 gene rearrangement were included. Overall, these patients had relatively uniform clinical manifestations. Most were older men (mean age, 67 years) who presented with lymphadenopathy, high-stage disease, and bone marrow involvement. All but two patients relapsed, demonstrated residual tumor, or had disease progression after an initial response to various therapies. Nine patients have died; these patients had a median survival of only 19 months. All cases could be classified within the broad morphologic spectrum previously described for MCL, and no predominant histologic subtype was observed. However, cases could be segregated into two major groups according to tissue architecture: one with a purely diffuse pattern and the other with at least a focal nodular component. Patients with purely diffuse tumors had a lower survival rate (0%) than those with tumors having a nodular component (62% survival rate). In contrast to the morphologic variability, these NHL exhibited a rather homogeneous immunophenotypic pattern. All cases demonstrated intense CD20 expression, with typically intense IgM and light chain expression, and relatively weak IgD expression. In no case was CD10 detected on the neoplastic cells. DNA content analysis showed aneuploidy only in three instances, and two groups of cases could be arbitrarily defined on the basis of their S-phase fraction. A relationship between a purely diffuse growth pattern and a high S-phase fraction (greater than 5%) was observed. As expected from this association, patients with tumors having high S-phase fractions fared worse (14% survival rate) than those patients with tumors showing lower S-phase fractions (57% survival rate). Thirteen NHLs from 12 patients had amplifiable bcl-1 gene rearrangements at the major translocation cluster (MTC). The bcl-1 breakpoints aggregated within a 63-bp region of the MTC, and the amplified tumor DNA from each patient had unique N-nucleotide junctional sequences and Ig joining region breakpoint sites.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1995

Controlled study of the putative interaction between famotidine and theophylline in patients with chronic obstructive pulmonary disease.

The effects of famotidine (80 mg per day), cimetidine (1600 mg per day), and placebo on theophylline pharmacokinetic parameters in chronic obstructive pulmonary disease (COPD) patients were compared. This was an open-label, randomized, three-period cross-over study, in which each subject first underwent a seven-day theophylline washout period, and thereafter received three single intravenous doses of theophylline (5 mg/kg infused over 30 minutes) during the study. Each of the experimental treatments was administered orally every 12 hours for a total of 9.5 days (19 doses). Theophylline was infused after the 17th dose of each treatment. Fourteen serial blood samples were collected before the start of each infusion, and for 30 hours after the end of each infusion. Plasma samples were assayed for theophylline, pharmacokinetic parameters were estimated, and treatment effects on each parameter were compared. Fourteen COPD patients completed all three periods of the investigation. Famotidine treatment had virtually no effect on any of theophylline's pharmacokinetic parameters. In contrast, cimetidine treatment significantly altered every pharmacokinetic parameter of theophylline as follows: Cimetidine decreased theophylline geometric mean CL from 2.74 L/h to 2.07 L/h (P < .001), and prolonged theophylline harmonic mean half-life from 6.6 to 9.6 hours (P < .001) and mean residence time from 10.8 to 15.0 hours (P < .001). Cimetidine treatment slightly increased theophylline volume of distribution by approximately 10%, and that change also was statistically significant (P = .032). The authors conclude that the treatment effects of cimetidine on theophylline pharmacokinetic parameters were in accord with those reported by others, and that famotidine treatment had no effect on any of theophylline's pharmacokinetic parameters in COPD patients.

Adult↗
PubMed1995

Aortic valve cusp microstructure: the role of elastin.

The aortic valve cusp is a three-layered structure, composed of differing amounts of collagen, elastin, and glycosaminoglycans. Little quantitative information is presently available on the amount, location, orientation, and overall structure of these constituents, particularly of elastin. We developed a technique to isolate aortic valve elastin in a morphologically intact state. Whole leaflets were digested in 0.1 N sodium hydroxide solution at a temperature of 75 degrees C. Both scanning electron microscopy and computerized three-dimensional reconstructions of serial sections showed a well-defined honeycomb or spongelike structure, suggesting that elastin forms a matrix that surrounds and links the collagen fiber bundles. This relationship between collagen and elastin is further supported by the naturally wavy configuration of the valve cusps, permitting elongations of 40%, even though collagen fibrils typically strain to 1% to 2% before fracture. Elastin likely acts to return collagen fibers back to their undeformed state, maintaining rest geometry.

Animals↗
PubMed1995

Ultrasonic tissue characterization of end-stage dilated cardiomyopathy.

The clinical use of angiotensin-converting enzyme (ACE) inhibitors now represents the standard of care for the treatment of chronic congestive heart failure. We utilized ultrasonic tissue characterization to define potentially salutary effects of treatment with ACE inhibitors on the material properties of the heart and its potential influence on cardiac remodeling at the cellular level. Ten 1-month-old cardiomyopathic (CM) Syrian hamsters were treated with captopril (2 g/L water ad libitum), and 10 CM and 5 normal hamsters were maintained untreated for 9 months. Hearts were excised, and backscattered radio-frequency data were acquired from 1200 independent sites from each specimen with a high-resolution 50-MHz acoustic microscope for calculation of integrated backscatter. Treatment with captopril elicited relative decreases in left ventricular (LV) wet weight, LV calcium concentration and integrated backscatter (IB) in treated as compared with untreated cardiomyopathic hearts without affecting LV collagen concentration. The IB from hearts of treated cardiomyopathic hamsters was significantly less in both grossly normal regions of myocardium (P < 0.02) and scar tissue regions (P = 0.0005) as compared with IB from hearts of untreated hamsters. The reduced integrated backscatter from hearts of treated cardiomyopathic hamsters indicates direct alterations in the material properties of cardiomyopathic hearts after captopril therapy. The lower IB from scar tissue in the treated animals was associated with decreased scar tissue calcification, which represents a novel therapeutic effect of captopril. This is the first report that delineates direct effects of ACE inhibitors on the material properties of both scar tissue and grossly normal myocardium at the cellular level in experimental dilated cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Parathyroid hormone (PTH)/PTH-related protein (PTHrP) receptor expression and mitogenic responses in human breast cancer cell lines.

Previous reports have shown the production of parathyroid hormone-related protein (PTHrP) by breast cancer cells in vivo and in vitro. We have investigated the expression of the PTH/PTHrP receptor by the human breast cancer cell lines MCF-7, ZR-75-1, T-47-D, SK-BR-3, Hs578T and MDA-MB231. Using reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analysis, we detected transcripts for the receptor in MCF-7, SK-BR-3 and MDA-MB231 cells. There was no evidence of receptor mRNA in ZR-75-1 and Hs578T cells. Furthermore, Northern blot analysis of mRNA from MCF-7 cells showed two transcripts of 1.5 and 2.4 kb which coded for the PTH/PTHrP receptor. Expression of PTH/PTHrP receptor mRNA by the breast cancer cell lines was also correlated with the detection of PTHrP transcripts. RT-PCR demonstrated PTHrP mRNA in MCF-7, ZR-75-1, T-47-D and Hs578T cells, but not in SK-BR-3 and MDA-MB231 cells. The detection of receptor transcripts was complemented by [3H]thymidine and bromodeoxyuridine incorporation studies, in which mitogenic responses to PTH and PTHrP were observed in MCF-7 cells but not in Hs578T cells. In response to both PTH(1-34) and PTHrP(1-34), quiescent MCF-7 cells proliferated in a similar dose-dependent manner (1.6-100 ng ml-1). No mitogenic effects of these peptides were observed with Hs578T cells. In addition, levels of intracellular cAMP were measured in MCF-7 and Hs578T cells in response to PTHrP(1-34). In MCF-7 cells there was a significant rise in cAMP with 100 ng ml-1 PTHrP(1-34). The expression of PTH/PTHrP receptor by breast cancer cells suggests that PTHrP may be a paracrine/autocrine regulator of breast carcinoma.

Base Sequence↗
PubMed1995

Cholesterol depletion and modification of COOH-terminal targeting sequence of the prion protein inhibit formation of the scrapie isoform.

After the cellular prion protein (PrPC) transits to the cell surface where it is bound by a glycophosphatidyl inositol (GPI) anchor, PrPC is either metabolized or converted into the scrapie isoform (PrPSc). Because most GPI-anchored proteins are associated with cholesterol-rich membranous microdomains, we asked whether such structures participate in the metabolism of PrPC or the formation of PrPSc. The initial degradation of PrPC involves removal of the NH2 terminus of PrPC to produce a 17-kD polypeptide which was found in a Triton X-100 insoluble fraction. Both the formation of PrPSc and the initial degradation of PrPC were diminished by lovastatin-mediated depletion of cellular cholesterol but were insensitive to NH4Cl. Further degradation of the 17-kD polypeptide did occur within an NH4Cl-sensitive, acidic compartment. Replacing the GPI addition signal with the transmembrane and cytoplasmic domains of mouse CD4 rendered chimeric CD4PrPC soluble in cold Triton X-100. Both CD4PrPC and truncated PrPC without the GPI addition signal (Rogers, M., F. Yehieley, M. Scott, and S. B. Prusiner. 1993. Proc. Natl. Acad. Sci. USA. 90:3182-3186) were poor substrates for PrPSc formation. Thus, it seems likely that both the initial degradation of PrPC to the 17-kD polypeptide and the formation of PrPSc occur within a non-acidic compartment bound by cholesterol-rich membranes, possibly glycolipid-rich microdomains, where the metabolic fate of PrPC is determined. The pathway remains to be identified by which the 17-kD polypeptide and PrPSc are transported to an acidic compartment, presumably endosomes, where the 17-kD polypeptide is hydrolyzed and limited proteolysis of PrPSc produces PrP 27-30.

Animals↗
PubMed1995

Modification of acute experimental autoimmune encephalomyelitis in the Lewis rat by oral administration of type 1 interferons.

The effect of orally administered type 1 interferons on the severity of acute experimental autoimmune encephalomyelitis (EAE), a T cell-mediated autoimmune disease, was examined by inoculation of Lewis rats with guinea pig myelin basic protein (GPMBP) and complete Freund's adjuvant. Rats were fed either rat species-specific or human recombinant type 1 interferon (IFN) or mock IFN daily for 7 days preceding immunization and for 21 days thereafter. There was a significant decrease in the clinical score and inflammatory foci in animals fed 5000 units IFN compared with mock-treated animals. There was a significant decrease in clinical score and number of inflammatory foci in spinal cord in animals fed orally 5000 units human recombinant IFN-alpha PO compared with SC 5000 units recombinant human IFN-alpha. Oral administration of type 1 interferon, as opposed to subcutaneous administration, inhibited the secretion of IFN-gamma from ConA-activated draining popliteal lymph node cells compared with mock-fed animals. These experiments demonstrate that acute EAE is more effectively inhibited by equivalent amounts of orally in contrast to parenterally administered IFN-alpha. These results suggest that type 1 IFNs are active by the oral route and have significant clinical and histologic effects in acute autoimmune disease.

Administration, Oral↗
PubMed1995

The relationship between white matter low attenuation on brain CT and vascular risk factors: a memory clinic study.

In order to discover the prevalence of white matter low attenuation (WMLA) in the brain and its relationship to vascular risk factors in our Memory Disorders Clinic patients we assessed brain CT scans of 202 patients referred to our clinic between January 1991 and December 1992. One hundred patients (49.5%) had WMLA, and the prevalence increased with increasing severity of cognitive impairment. It was 12% in patients with no evidence of dementia, 32% in those with isolated memory loss, and 59%) in patients with possible or probable dementia. There was a correlation between WMLA and systolic blood pressure, heart disease, peripheral vascular disease, focal neurological signs on examination and central atrophy on CT. No correlation was found between WMLA and low blood pressure, blood glucose or cholesterol level. Our findings indicate that WMLA probably plays an important role in cognitive impairment, and that thromboembolic rather than haemodynamic factors are probably more important in its pathogenesis.

Aged↗