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Biomedical subjects

N Miller

Publications and source records attributed to N Miller.

At least 109 records · Page 6Linked to original sources
PubMed1995

Effects of modulators of tyrosinase activity on expression of murine interleukin-2 cDNA driven by the tyrosinase promoter.

Sequence analysis of the promoter region of the murine tyrosinase gene identified various consensus motifs including AP2 sites, cAMP and TPA response elements (CREs/TREs) and retinoic acid response element (RARE) half-sites. By linking two different promoter lengths (2.5 kb or 769 bp) to murine interleukin-2 (IL-2) cDNA we have used IL-2 production by transduced B16 cells to monitor response to inducing agents capable of acting through these elements. Aminophylline or theophylline (0.1-2 mM) added to the culture medium of transfected B16, but not 3T3, cells, increased IL-2 secretion significantly (P > 0.05) in a dose-dependent fashion. This response was comparable in cells transfected with either the full length or the truncated promoter. Therefore, the cAMP responsiveness of the tyrosinase promoter probably is mediated by CREs and not AP2 sites, since the truncated promoter contains the former but not the latter regions. Retinoic acid at various concentrations (0.1-1 microM) evoked a standard increase in IL-2 production. Responses were similar for both promoter constructs, which suggests either that each RARE half-site can confer the full retinoic acid response, or that retinoic acid is mediating its effect through pathways independent of the RARE sites. TPA (2 nM-2 microM) had no effect on IL-2 production. These results demonstrate that the tyrosinase promoter can be induced by certain pharmacological agents and raise the possibility that administration of such substances may enhance expression of therapeutic genes controlled by this promoter.

3T3 Cells↗
PubMed1995

Use of meta-analysis for testing theory.

Within the context of the general superiority of meta-analytic reviews over qualitative reviews, we emphasize the fragility of meta-analytic outcomes, especially when the effects of moderator variables remain unexamined. We consider the contribution to increased theoretical understanding made by moderator analyses both of methodological and substantive variables in psychological, health, and medical research. The potential contribution of meta-analysis to understanding the process underlying established relationships and to assessment of the convergent and discriminative construct validity of previously used concepts is discussed.

Bias↗
PubMed1995

Expression of intercellular adhesion molecule-1 on human thyroid cells from patients with autoimmune thyroid disease: study of thyroid xenografts in nude and severe combined immunodeficient mice and treatment with FK-506.

It has been suggested that intercellular adhesion molecule-1 (ICAM-1) may play an important role in the initiation, localization, and perpetuation of autoimmune thyroid diseases (AITD). In an effort to clarify its role, we have investigated the expression of ICAM-1 on thyroid epithelial cells (TEC) of patients with AITD, patients with nontoxic goiter (NTG), and normal subjects (PN) by flow cytometric analysis under basal conditions and after modulation with cytokines, before and after 8 weeks of thyroid tissue xenotransplantation in nude athymic mice (which lyses all passenger lymphocytes), and in severe combined immunodeficient (SCID) mice where these cells survive. Before xenografting, ICAM-1 was expressed on 56% of TEC from Hashimoto's thyroiditis (n = 5), 54% of Graves' disease (n = 6), 15% of NTG (n = 5), and 12% of PN TEC. After the xenografts had been 8 weeks in nude mice, ICAM-1 expression decreased markedly in AITD TEC [from 56% to 10% in Hashimoto's thyroiditis (P < 0.001) and from 54% to 8% in Graves' disease (P < 0.01)], but did not change significantly in NTG or PN. After the xenografts had been 8 weeks in SCID mice, the expression of ICAM-1 was significantly higher on TEC of AITD compared with the same tissue in nude mice. When the SCID mice engrafted with AITD tissue were treated with the anti-CD4+ T (helper) cell agent FK-506, the expression of ICAM-1 was reduced significantly compared with that in the original tissue or that in nontreated mice engrafted with the same tissue. The proportion of TEC that were ICAM-1 positive was up-regulated in all cases by certain cytokines (e.g. interferon-gamma and tumor necrosis factor-alpha applied alone or in combination). We also detected the presence of ICAM-1 in AITD frozen tissues using an immunohistochemical technique. These data suggest a role for ICAM-1 in human AITD. However, the expression of ICAM-1 appears to be a secondary phenomenon in response to the immune assault, rather than a primary event. Our results support the idea that TEC may act as passive captives to immunological events in human AITD.

Animals↗
PubMed1995

Integrating smoking cessation into routine public prenatal care: the Smoking Cessation in Pregnancy project.

OBJECTIVES: In 1986, the state health departments of Colorado, Maryland, and Missouri conducted a federally-funded demonstration project to increase smoking cessation among pregnant women receiving prenatal care and services from the Women, Infants, and Children (WIC) program in public clinics. METHODS: Low-intensity interventions were designed to be integrated into routine prenatal care. Clinics were randomly assigned to intervention or control status; pregnant smokers filled out questionnaires and gave urine specimens at enrollment, in the eighth month of pregnancy, and postpartum. Urine cotinine concentrations were determined at CDC by enzyme-linked immunosorbent assay and were used to verify self-reported smoking status. RESULTS: At the eighth month of pregnancy, self-reported quitting was higher for intervention clinics than control clinics in all three states. However, the cotinine-verified quit rates were not significantly different. CONCLUSIONS: Biochemical verification of self-reported quitting is essential to the evaluation of smoking cessation interventions. Achieving changes in smoking behavior in pregnant women with low-intensity interventions is difficult.

Adult↗
PubMed1995

Pronunciation errors in acquired speech disorders: the errors of our ways.

There are conflicting arguments over whether perceptual analysis of speech errors can be used for a differential diagnosis of acquired motor speech disorders. This study addressed the issue using a narrow phonetic transcription of single-word naming and repetition responses, and a comprehensive taxonomy of error types. Speaker groups were selected according to criteria which were not variables to be investigated later. The listener-perceived segmental errors of 30 post-stroke speech-impaired speakers (six spastic dysarthric; 12 speech dyspraxic and phonemic paraphasic without dysphasia; 12 speech dyspraxic and phonemic paraphasic with dysphasia) were analysed and subjected to statistical analysis. A variety of analyses failed to establish any consistently reliable differential diagnostic pointers. It is concluded that reasons for the inconclusiveness of perceptual assessment go beyond investigatory methodological problems and embrace issues of underlying theory as well.

Adult↗
PubMed1995

Stability of remission during tricyclic antidepressant continuation therapy for dysthymia.

Sixty-four of 73 patients with DSM-III-R dysthymia who responded to short-term treatment with tricyclic antidepressants (TCAs) completed 16 to 20 weeks of continuation therapy on the same medication. Forty-one of 46 full remitters remained in full remission, while 5 became partial remitters during the continuation treatment. Of 18 partial remitters, 8 became fully remitted, 8 remained partial remitters, and 2 relapsed. Thus the stability of remission in dysthymic subjects treated with TCA seems quite favorable during continuation treatment.

Adult↗
PubMed1994

Chromosome abnormalities in meningeal neoplasms: do they correlate with histology?

Thirty-three meningeal neoplasms were karyotyped, and the results were compared with histologic features. Thirteen neoplasms had no discernible abnormality or sex chromosome loss only; nine had monosomy or structural abnormality involving only chromosome 22; and 11 had other chromosome abnormalities with or without chromosome 22 involvement. Histologic evidence of invasion was not associated with an abnormal karyotype in the three angioblastic tumors examined. All seven fibroblastic meningiomas had abnormal karyotypes, with monosomy 22 the most common change. Abnormal karyotypes were detected in 76% of syncytial and 55% of transitional meningiomas. When these results were combined with those from 259 meningeal tumors reported since 1987, abnormal karyotypes were detected in at least half of all histologic types. Chromosome changes secondary to those involving chromosome 22 may indicate additional areas of the genome that play a role in tumor progression. In the combined series, chromosome losses were most frequently observed in meningiomatous and transitional histologies; chromosomes 1, 6, 14, 18, and Y each were lost in 10 or more meningiomas, whereas only chromosome 20 was gained at the same frequency. Structural abnormalities most frequently involved chromosome 1. These changes are distinctly different from those observed in other common intracranial neoplasms, specifically astrocytic neoplasms.

Adult↗
PubMed1994

Gene transfer and antisense nucleic acid techniques.

Attempts to suppress a harmful genetic trait by antisense means, or to restore a normal phenotype by gene transfer, attract much publicity. This is especially the case where clinical trials incorporating such methodologies have been initiated, such as antisense oligonucleotide therapies for some types of leukaemia, antisense gene-transfer therapy for a form of lung cancer, and gene-transfer therapies for adenosine deaminase deficiency, severe combined immunodeficiency disease, and various forms of cancer including brain tumours and melanoma. However, translation of laboratory success into treatment or control of disease is unlikely to be straightforward. Here, Nick Miller and Richard Vile summarize the rationale, problems and potential of such techniques as applied to parasitic disease.

Journal Article↗
PubMed1994

Studies of human peripheral blood mononuclear cells (PBMC) from patients with subacute thyroiditis in severe combined immunodeficient (SCID) mice: less production of human interferon gamma than that seen for Graves' disease.

Human peripheral blood mononuclear cells (PBMC) from 2 patients with de Quervain's subacute thyroiditis (SAT), 2 with Graves' disease (GD), and 3 normal persons (N) were engrafted into severe combined immunodeficient (SCID) mice so as to study whether SAT PBMC would differ immunologically from GD PBMC in vivo. Human IgG was detected in all mice engrafted with PBMC from either group of patients or normal persons. Thyroid Stimulating Antibody (TSAb) was detected in the sera of mice with PBMC from SAT or GD patients, but not N. Thyroperoxidase (TPO)-antibody (Ab) and/or thyroglobulin (Tg)-Ab was detectable in the mice with GD PBMC only, but not in those with SAT or normal PBMC. The production of interferon gamma (IFN gamma) in mice engrafted with N PBMC was 8, 13 and 14 U/ml, similar to values found in sera of SCID mice with SAT PBMC (14 and 11 U/ml), i.e., much lower than that seen for GD PBMC (127 and 78 U/ml); this is consistent with the view that, compared to GD T lymphocytes, that there is probably a lower number of T lymphocytes sensitized to the thyrotrophin (TSH) receptor antigen in SAT patients. Another possibility is that the transient thyroidal antigenic release seen in the acute (hyperthyroid) phase may be insufficient for adequate T cell sensitization. Still other possibilities include the effect of more severe hyperthyroidism of GD on T cell sensitization, and CD4/CD8 cell ratios. In any event, these results are consistent with our previous view that antigenic release in SAT will not itself lead to autoimmune thyroid disease.

Adult↗
PubMed1994

Studies of human thyroid xenografts from Hashimoto's thyroiditis in severe combined immunodeficient (SCID) mice: detection of thyroid stimulation-blocking antibody.

Human thyroid xenografts from 7 patients with Hashimoto's thyroiditis (HT) and 3 normal persons (N) were xenografted into severe combined immunodeficient (SCID) mice to study the intrathyroidal lymphocytes that were expected to survive in these animals. Human IgG was detected in all mice engrafted with HT thyroid tissue peaking at 6-10 weeks after xenografting. Thyroperoxidase-antibody (TPO-Ab) was also detected in all mice with HT thyroid grafts peaking at 4-6 weeks after xenografting, reaching up to 44% of donors' original concentrations. In contrast, maximal thyroglobulin (Tg)-Ab production in some SCID mice with HT thyroid grafts was higher than the donors' original level, and was detectable in mice with thyroid grafts from Tg-Ab-negative HT donors. Thyroid stimulation-blocking antibody (TSBAb) was found in 2 mice with thyroid xenografts from 1 HT patient whose original serum TSBAb and thyrotropin-binding inhibitor immunoglobulin (TBII) had been positive; the maximal TSBAb level in SCID mice exceeded the donor's original level. TSBAb production in SCID mice reached its peak at 10 weeks after xenografting, i.e., later than that of thyroid-stimulating antibody (TSAb) observed in our recent report, suggesting the existence of distinct intrathyroidal B cell autoreactive clones of different life span responsible for secreting TSAb or TSBAb. When autologous peripheral blood mononuclear cells (PBMC) were engrafted alone (without thyroid tissue), TSBAb was undetectable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Effect of FK-506 on xenografted human Graves' thyroid tissue is severe combined immunodeficient mice.

OBJECTIVE: We studied the macrolide antibiotic FK-506, an immunosuppressive agent, in an attempt to ameliorate the lesion of autoimmune thyroid disease in human thyroid tissue xenografted into severe combined immunodeficient (SCID) mice. It was not felt appropriate to employ this agent directly in patients with autoimmune thyroid disease because adequate therapeutic modalities are available and the introduction of new, experimental agents could not be justified. Moreover, the study of the tissue before and after treatment could not have been undertaken directly in patients. DESIGN: Human thyroid xenografts from four patients with Graves' disease and two normal persons were xenografted into SCID mice. Two weeks after xenografting, human immunoglobulin G (IgG) was detectable in all SCID mice xenografted with Graves' thyroid tissue. Mice were divided into two groups with human IgG levels similar to each other. Mice in the first group were treated with FK-506 daily for 6 weeks; mice in the second (similar) group were given phosphate-buffered saline (PBS) only (control group). MEASUREMENTS: Blood samples were taken every 2 weeks from the tail veins for human IgG, thyroid stimulating antibody, thyroperoxidase antibodies, thyroglobulin antibodies, and interferon-gamma (IFN-gamma). After 8 weeks treatment, animals were sacrificed; thyroid tissue was examined histologically and for thyrocyte HLA-DR expression. FK-506 was also added to thyrocytes in in-vitro tissue culture conditions. RESULTS: After 4-6 weeks of FK-506 therapy, human IgG, all thyroid antibodies and IFN-gamma were suppressed, while the levels remained elevated in the control group. Lymphocytic infiltration virtually disappeared in the human thyroid tissue of the FK-506-treated mice and thyrocyte HLA-DR expression markedly declined; in the control mice, lymphocytic infiltration remained heavy and HLA-DR expression remained high. On the other hand, FK-506 added directly to thyrocytes in vitro (without lymphocytes) did not reduce thyrocyte HLA-DR expression. CONCLUSIONS: FK-506 appears to suppress the activation of intrathyroidal lymphocytes, but not thyrocytes. From these observations, it is concluded that this agent, by its action on intrathyroidal lymphocytes, is able to ameliorate the immunologically mediated histological and serological disturbance in human autoimmune thyroid disease, at least under these circumstances.

Animals↗
PubMed1994

Evaluation of Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test and PCR for direct detection of Mycobacterium tuberculosis in clinical specimens.

The Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (AMTD) is a direct specimen assay for the identification of Mycobacterium tuberculosis from respiratory samples. rRNA is amplified, and the product is detected with a specific chemiluminescent probe. We performed a retrospective evaluation of three separate respiratory specimens from each of 250 patients by using the AMTD and compared the results with those of microscopy, culturing, and a patient chart review. From the latter results, 198 patients (594 specimens) were found negative for M. tuberculosis by culturing and clinical criteria. The overall specificity of the AMTD after discrepancy resolution was 98.5% (585 of 594). There were 52 patients with culture-proven and/or clinically diagnosed tuberculosis. Of these 156 specimens, the organism was cultured from 142 (91%), and acid-fast microscopy was positive for 105 (67.3%). The AMTD was positive for 142 (91%) specimens from these patients. Tuberculosis patient samples were tested by a PCR assay which uses primers for amplification of the IS6110 insertion sequence of the M. tuberculosis complex. The PCR assay detected 144 of the 156 (92.3%) specimens. Overall, when three specimens per patient were examined, the AMTD found all 52 patients positive for tuberculosis, while the PCR assay found 51 patients positive by agarose gel analysis and all 52 patients positive by Southern blot hybridization.

Bacteriological Techniques↗
PubMed1994

Lipid peroxidation in rats chronically fed ethanol.

Chronic alcohol consumption induces cytochrome P450IIE1, enabling habitual abusers to consume far greater quantities of alcohol than normal subjects. This pathway of metabolism leads to the production of free radical species, which cause tissue damage through peroxidation of cell membranes. Groups of Wistar rats of equal male: female ratio (n = 24) were fed alcohol by gavage twice daily to achieve a dosage of 15 g/kg body weight. Mean peak blood alcohol concentrations of 186 mg% were produced in males and 156 mg% in females. The animals were allowed free access to standard laboratory chow and water. Control animals were pair-fed to the alcoholic group and fed isocaloric glucose by gavage. Groups of animals were killed between 9 and 11 am on consecutive mornings, after nocturnal feeding, since it has previously been shown that fasting rapidly depletes hepatic glutathione concentrations. Hepatic glutathione was measured by a spectrophotometric enzymatic recycling procedure. As a marker of lipid peroxidation hepatic malonaldehyde (MDA) was measured by high performance liquid chromatography. Hepatic MDA was increased in the alcoholic group (p < 0.001), as was total hepatic glutathione (p < 0.0001). Plasma concentrations of alpha-tocopherol were increased in the alcoholic group, but ascorbic acid and superoxide dismutase values were not affected. No sex differences were detected. The increased MDA production in the alcohol group is strong evidence that lipid peroxidation is a mechanism of alcoholic tissue damage. The rise in hepatic glutathione may be an adaptive response to free radical production that protects the rat against tissue damage.

Animals↗
PubMed1994

Effect of removing human Graves' thyroid xenografts after eight weeks in nude mice and rexenografting them into SCID mice.

Human thyroid xenografts from four patients with Graves' disease (GD) and two normal persons were initially xenografted into nude mice. Eight weeks after xenografting, the thyroid tissue appeared normal; indeed, thyroid infiltrating lymphocytes in the GD xenograft could no longer be identified when analyzed histologically. Thus, human immunoglobulin G (IgG), thyroperoxidase (TPO)-antibodies (Abs), thyroglobulin (Tg)-Abs, thyroid-stimulating antibodies (TSAb), and thyrocyte histocompatibility leucocyte antigen (HLA)-DR expression were undetectable. These same tissues were retrieved from the nude mouse and rexenografted into severe combined immunodeficient (SCID) mice (with no prior xenograft); autologous peripheral blood mononuclear cells (PBMC) or CD8-depleted PBMC (non-CD8 cells) were simultaneously injected into some of these SCID mice. Engraftment of a GD thyroid rexenograft (TH) alone did not cause IgG, TSAb, TPO-Ab, or Tg-Ab production, thyrocyte HLA-DR expression, or lymphocytic infiltration in thyroid grafts. Engraftment of GD PBMC or non-CD8 cells alone (i.e. without a thyroid xenograft) caused human IgG to rise, but only minimal titers of thyroid antibodies appeared. When TSAb, TPO-Ab, and Tg-Ab were quantified, GD TH plus PBMC-engrafted SCID mice showed significantly higher production of each antibody than that of GD PBMC alone, and this phenomenon was further enhanced by the removal of CD8+ cells. GD thyrocytes showed marked HLA-DR expression at human surgery; however, after 8 weeks' sojourn in nude mice, DR expression disappeared. After a further 8 weeks following rexenografting into SCID mice, TH plus PBMC resulted in a reappearance of DR expression only in GD but not in grafts from normal persons, and this was enhanced by the depletion of CD8 cells. These results were also in parallel with histological findings inasmuch as the normal tissue remained normal with no thyroid antibodies appearing with PBMC or CD8-depleted cells. In experiments from two GD patients, autologous skeletal muscle as well as thyroid tissue were xenografted into nude mice. Eight weeks after xenografting, these were rexenografted into SCID mice that contained prior autologous primary GD thyroid xenografts. Histological findings showed new lymphocytic infiltration in rexenografted thyroid tissues in the SCID mice but not in autologous skeletal muscle. This signifies that the immune assault in GD is specifically targeted to the thyroid tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

A comparison of the properties of different retroviral vectors containing the murine tyrosinase promoter to achieve transcriptionally targeted expression of the HSVtk or IL-2 genes.

To target therapeutic genes specifically to melanoma cells, we have constructed recombinant retroviruses where transcriptional control of the murine interleukin-2 (mIL-2) or herpes simplex virus thymidine kinase (HSVtk) genes is provided by the 5' promoter region of the murine tyrosinase gene. Tissue-specific expression of these genes is observed both at the mRNA and protein levels in the B16 melanoma line compared with NIH3T3 fibroblasts. Thus, B16 cells infected with one such retrovirus containing the HSVtk gene exhibited a > 90% reduction in colony-forming efficiency after exposure to 1 microgram/ml ganciclovir, relative to controls, whereas similarly infected NIH3T3 cells showed < 10% reduction in colony-forming efficiency under comparable conditions. The degree of preservation of tissue-specific expression from the internal tyrosinase promoter depended upon the exact molecular design of the vector, possibly as a consequence of the interference between closely juxtaposed promoters within the provirus. Our results show that retroviral vectors can be prepared with the capacity to regulate expression of inserted genes specifically in a particular cell type and may be useful for developing efficient, targeted vectors for the in vivo delivery of genetic therapies for malignant melanoma.

3T3 Cells↗