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Biomedical subjects

D M Miller

Publications and source records attributed to D M Miller.

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

Cytomegalovirus and transcriptional down-regulation of major histocompatibility complex class II expression.

CD4(+)T lymphocytes are a significant component of the afferent and efferent arms of adaptive immunity and are critical for controlling viral infections. CD4(+)T lymphocytes secrete cytokines that augment CD8(+)T lymphocyte and B lymphocyte responses and directly inhibit viral replication. The interface between the CD4(+)T lymphocyte and virus is the major histocompatibility complex (MHC) class II molecule. Cytomegalovirus, a beta-herpesvirus, has evolved mechanisms for inhibiting MHC class II expression and thus escaping CD4(+)T lymphocyte immunosurveillance. Herein, we review cytomegalovirus-mediated down-regulation of inducible and constitutive MHC class II expression, while focusing on lesions that occur at the level of MHC class II transcription.

Animals↗
PubMed2001

Presence of protein deposits on 'cleaned' re-usable anaesthetic equipment.

Twenty previously used and supposedly clean, sterilised laryngeal mask airways, five bougies and five Magill forceps from the operating theatre, and 61 laryngoscope blades from different sites within a single hospital were randomly collected and stained with erythrosin B dye, which stains proteins if present on surfaces. All 20 laryngeal mask airways had been used before and were stained: four (20%) showed heavy staining, five (25%) moderate staining and 11 (55%) mild staining. Two unused laryngeal mask airways used as controls were without staining. Thirty-four of 44 (77%) laryngoscope blades taken from the operating theatres, six of seven (86%) from the overnight intensive recovery room and all 10 (100%) from the wards were stained. None of the other items was totally clean. These findings suggest that current cleaning methods do not remove all proteinaceous material.

Anesthesiology↗
PubMed2001

The laryngeal mask and VBM laryngeal tube compared during spontaneous ventilation. A pilot study.

BACKGROUND AND OBJECTIVE: The laryngeal tube is a variant of the oesophageal obturator airway. The manufacturer claims that it is an alternative to ventilation with a facemask, laryngeal mask or endotracheal tube. To date, published studies have only involved controlled ventilation. We wished to find out if its use in spontaneous ventilation was equivalent to using the laryngeal mask airway. METHODS: We have compared the laryngeal tube with the laryngeal mask in a randomized prospective study involving patients breathing spontaneously under general anaesthesia. Criteria and a scoring system were used for the comparison. A sequential analysis chart with P=0.01 was chosen for each of two anaesthetists. RESULTS: Only seven and 10 pairs of patients were required to indicate that the laryngeal tube was poorer at airway maintenance than the laryngeal mask. Of the 17 patients who had received the laryngeal tube, successful airway maintenance was only possible in seven. In the remaining 10 patients, the laryngeal tube was abandoned and the rescue airway was the laryngeal mask in all cases. All 17 patients randomized to the laryngeal mask were successfully managed. CONCLUSIONS: We conclude that the laryngeal tube is not a satisfactory device for management of the airway during spontaneous ventilation.

Adult↗
PubMed2001

Recovery following acute exacerbations of multiple sclerosis: from impairment to quality of life.

To observe the pattern of recovery after treatment with intravenous Methylprednisolone (i.v. MP) for a relapse of multiple sclerosis (MS), and to determine the best time to plan further interventions such as rehabilitation, we assessed consecutive outpatients (n = 24) treated with i.v. MP for a relapse over a period of 12 weeks. Outcomes measures used were the Expanded Disability Status Scale (EDSS), the Incapacity Status Scale (ISS), the MOS Short Form-36 (SF-36), the Mental Health Inventory (MHI), and the MS-Related Symptom Checklist (MSSCL). There was statistically significant early improvement of EDSS and ISS scores, which was sustained until week 12, and significant improvement of MHI and MSSCL scores between 4 and 12 weeks. Although trends for improvement of scores reflecting the same pattern of recovery were observed with the SF-36 physical and mental composites, these changes did not reach statistical significance. Our results suggest that improvement of impairments and disability after treatment with i.v. MP for a relapse of MS occurs early, while improvement of subjective health status is delayed. Even after maximum improvement is reached, patients are left with multiple symptoms and functional limitations, and may benefit from additional rehabilitative interventions.

Adult↗
PubMed2001

Hematology grants workshop-2001.

This year the Hematology Grants Workshop, chaired by Dr. Todd, includes a comprehensive listing of available National Institutes of Health, Department of Veterans Affairs, and non-federal grants applicable to fellows and junior faculty as well as to established investigators. In Section II, Dr. Miller discusses the essential principles of successful grant writing with a special emphasis on the young investigator. He highlights the best strategies to take and the common mistakes to avoid. In Section III, Dr. Silverstein outlines the structure of the current NIH Integrated Review Group (IRG) system and the study sections of the most relevance to hematology. He traces the path that a grant takes from review to funding including the way in which grants are reviewed at NIH Study Section Meetings and provides advice in the preparation of revised applications.

Consensus Statements as Topic↗
PubMed2001

Intra- and intermolecular triplex DNA formation in the murine c-myb proto-oncogene promoter are inhibited by mithramycin.

Mithramycin inhibits transcription by binding to G/C-rich sequences, thereby preventing regulatory protein binding. However, it is also possible that mithramycin inhibits gene expression by preventing intramolecular triplex DNA assembly. We tested this hypothesis using the DNA triplex adopted by the murine c-myb proto-oncogene. The 5'-regulatory region of c-myb contains two polypurine:polypyrimidine tracts with imperfect mirror symmetry, which are highly conserved in the murine and human c-myb sequences. The DNA binding drugs mithramycin and distamycin bind to one of these regions as determined by DNase I protection assay. Gel mobility shift assays, nuclease and chemical hypersensitivity and 2D-gel topological analyses as well as triplex-specific antibody binding studies confirmed the formation of purine*purine:pyrimidine inter- and pyrimidine*purine:pyrimidine intra-molecular triplex structures in this sequence. Mithramycin binding within the triplex target site displaces the major groove-bound oligonucleotide, and also abrogates the supercoil-dependent H-DNA formation, whereas distamycin binding had no such effects. Molecular modeling studies further support these observations. Triplex-specific antibody staining of cells pretreated with mithramycin demonstrates a reversal of chromosomal triplex structures compared to the non-treated and distamycin-treated cells. These observations suggest that DNA minor groove-binding drugs interfere with gene expression by precluding intramolecular triplex formation, as well as by physically preventing regulatory protein binding.

Animals↗
PubMed2000

Localization and enhanced current density of the Kv4.2 potassium channel by interaction with the actin-binding protein filamin.

Kv4.2 potassium channels play a critical role in postsynaptic excitability. Immunocytochemical studies reveal a somatodendritic Kv4.2 expression pattern, with the channels concentrated mainly at dendritic spines. The molecular mechanism that underlies the localization of Kv4.2 to this subcellular region is unknown. We used the yeast two-hybrid system to identify the Kv4.2-associated proteins that are involved in channel localization. Here we demonstrate a direct interaction between Kv4.2 and the actin-binding protein, filamin. We show that Kv4.2 and filamin can be coimmunoprecipitated both in vitro and in brain and that Kv4.2 and filamin share an overlapping expression pattern in the cerebellum and cultured hippocampal neurons. To examine the functional consequences of this interaction, we expressed Kv4.2 in filamin(+) and filamin(-) cells and performed immunocytochemical and electrophysiological analyses. Our results indicate that Kv4.2 colocalizes with filamin at filopodial roots in filamin(+) cells but shows a nonspecific expression pattern in filamin(-) cells, with no localization to filopodial roots. Furthermore, the magnitude of whole-cell Kv4.2 current density is approximately 2.7-fold larger in filamin(+) cells as compared with these currents in filamin(-) cells. We propose that filamin may function as a scaffold protein in the postsynaptic density, mediating a direct link between Kv4.2 and the actin cytoskeleton, and that this interaction is essential for the generation of appropriate Kv4.2 current densities.

Actins↗
PubMed2000

1,3,5-Trialkyl-2,4,6-triiodobenzenes: novel X-ray contrast agents for gastrointestinal imaging.

Examination of the gastrointestinal (GI) tract has been performed for decades using barium sulfate. Although this agent has many recognized limitations including extreme radiopacity, poor intrinsic affinity for the GI mucosa, and very high density, no alternative contrast agents have emerged which produce comparable or better contrast visualization. In fact, the various techniques of the GI radiologic examination (i.e., single contrast, double contrast, biphasic) were developed to compensate for its limitations. Each of these techniques requires complex patient manipulation to achieve adequate mucosal coating or compression to overcome the marked radiopacity of barium sulfate in order to obtain a diagnostically useful examination. A series of novel radiopaque oils, the 1,3, 5-trialkyl-2,4,6-triiodobenzenes, was designed to improve the efficacy, stability, and safety of barium formulations. These substances were prepared in two steps from 1,3,5-trichlorobenzene. Compound 17 (1,3,5-tri-n-hexyl-2,4,6-triiodobenzene), formulated as an oil-in-water emulsion, was found to be well-tolerated in rodents (mice, hamsters, rats) following acute oral and/or intraperitoneal administrations at 4 times the anticipated human clinical dose. No metabolism of 17 was detected in rat, hamster, dog, monkey, or human hepatic microsomes, suggesting the lack of oral toxicity was a consequence of poor absorption. In imaging experiments in dogs, emulsions of 17 have demonstrated excellent mucosal coating and improved radiodensity relative to barium sulfate suspensions. On the basis of the preliminary imaging and toxicity data, compound 17 was selected as a potential development candidate.

Absorption↗
PubMed2000

Cytomegalovirus induces sialyl Lewis(x) and Lewis(x) on human endothelial cells.

BACKGROUND: Cytomegalovirus (CMV) is the primary viral cause of complications in transplant recipients. We sought to understand the mechanisms of its dissemination and induction of vascular disease, which may lead to transplant complications. Sialyl Lewis(x) (sLe(x)) and Lewis(x) (Le(x)) are known for their roles in mediating cell adhesion and as tumor-associated carbohydrate antigens. Herein we explore whether CMV induces surface expression of these important molecules in endothelial cells (EC). METHODS: Flow cytometry was used to detect surface expression of sLe(x) and Le(x) on CMV-infected human umbilical vein endothelial cells (HUVEC), with or without ultraviolet inactivation of the virus. To elucidate mechanisms of CMV-mediated induction, mRNA coding for predominant HUVEC sialyltransferases (ST) and fucosyltransferases (FT), key enzymes in sLe(x) and Le(x) synthesis, was analyzed by Northern blot. Dual immunohistochemical staining for sLe(x) and Le(x) expression of human colon and placental tissue was performed to investigate in vivo relevance. RESULTS: sLe(x) expression on CMV-infected HUVEC was strongly up-regulated by 8 days after inoculation. Le(x) expression was detectable earlier and increased steadily over time. In contrast, ultraviolet-inactivated CMV did not induce expression of these molecules. Northern blot assays demonstrated higher levels of important EC glycosyltransferases ST-IV, FT-III, and FT-IV in CMV-infected EC. Finally, high levels of sLe(x) and Le(x) were expressed in CMV-infected EC in vivo. CONCLUSIONS: Given the known biologic functions of sLe(x) and Le(x), we suggest that CMV induction of these molecules may have widespread consequences ranging from CMV dissemination to induction of CMV-associated vascular disease, including thrombosis.

Antigens, Surface↗
PubMed2000

Human cytomegalovirus blocks interferon-gamma stimulated up-regulation of major histocompatibility complex class I expression and the class I antigen processing machinery.

Interferon-gamma stimulates major histocompatibility complex (MHC) class I antigen processing and presentation by inducing the expression of major histocompatibility complex class I heavy chains, beta2-microglobulin, the transporter associated with antigen processing, and components of the proteasome complex. We demonstrate that this effect of interferon-gamma on the major histocompatibility complex class I pathway is inhibited in human cytomegalovirus-infected fibroblasts and endothelial cells. This is the result of a direct human cytomegalovirus/cell interaction leading to a block in interferon-gamma signal transduction beginning at early times after infection and peaking at 72 hr after infection. These observations suggest a novel level of herpesvirus interference with antigen processing: protection of infected cells from the immunoregulatory effects of interferon-gamma. Thus protected, human cytomegalovirus persists and may exacerbate graft rejection or lead to fulminant infection in the immunocompromised transplant recipient.

Antigen Presentation↗
PubMed2000

Structural analysis of alpha-enolase. Mapping the functional domains involved in down-regulation of the c-myc protooncogene.

Myc-binding protein-1 (MBP-1) is a 37-kDa protein with sequence homology to the 3' portion of the alpha-enolase gene. alpha-Enolase is a 48-kDa protein, which plays a critical role in the glycolytic pathway. MBP-1 binds to the c-myc P2 promoter and down-regulates c-myc expression. We have investigated the role of alpha-enolase in regulation of the c-myc protooncogene. RNase protection assay shows that alpha-enolase is transcribed into a single RNA species in HeLa cells. A start codon, 400 base pairs downstream of the alpha-enolase ATG, corresponds to the MBP-1 ATG, suggesting that MBP-1 is an alternative translation initiation product of the alpha-enolase RNA. Domain mapping was performed using constructs containing truncations of the alpha-enolase gene. In vitro binding to the c-myc gene was abolished after deletion of the N-terminal portion of alpha-enolase. In order to determine the relationship between DNA binding activity and transcription inhibition, we performed co-transfection assays in HeLa cells. These studies confirmed that an N-terminal deletion of alpha-enolase is unable to down-regulate c-myc promoter activity. Our data suggest that alpha-enolase plays an important role in regulation of c-myc promoter activity in the form of an alternative translation product MBP-1, which is distinct from its role as a glycolytic enzyme.

Biomarkers, Tumor↗
PubMed2000

National use of the transesophageal echocardiographic-guided approach to cardioversion for patients in atrial fibrillation.

Transesophageal echocardiographic (TEE)-guided cardioversion of patients in atrial fibrillation (AF) of >2 days' duration is used as an alternative to conventional therapy. The purpose of this study was to investigate practice patterns employed for stroke prophylaxis in patients with AF who underwent cardioversion, and to determine the relative use of conventional and TEE-guided management strategies. We forwarded regionally stratified survey questionnaires to 947 clinical practices within the United States. The 10-question questionnaire queried demographic and clinical practice volumes and practices for managing patients with AF who underwent cardioversion. In addition, we used historical data to determine longitudinal use patterns of the TEE-guided approach for a large institution over 7 years. The 197 completed and returned surveys yielded a return rate of 20.8%. The TEE-guided approach was employed in approximately 12% of total cardioversions, but 75% of practices indicated that they employed transesophageal echocardiography only occasionally. The TEE-guided approach was associated with community size (r = 0.19; p<0.008), type of practice (r = 0.26; p = 0.001), total use of transesophageal echocardiography (r = 0.48; p<0.001), and volume of cardioversions (r = 0.28; p<0.001). Importantly, there was little consensus on the most appropriate clinical indications for TEE-guided cardioversions, and the proportions of TEE-guided cardioversion to total number of electrical cardioversions remained stable over 7 years. Practice volume and physician training may be the most important variables in the adoption of the TEE approach.

Ambulatory Care↗
PubMed2000

Clinical significance of the multiple sclerosis functional composite: relationship to patient-reported quality of life.

BACKGROUND: The Multiple Sclerosis Functional Composite (MSFC) was recommended by a task force of the National Multiple Sclerosis Society as a new clinical outcome measure for clinical trials. The task force recommended that the MSFC be validated against other measures of the disease, such as patient-reported quality of life. METHODS: Three hundred patients with multiple sclerosis (MS) representing the spectrum of disease severity were included in this cross-sectional study. The MSFC and Kurtzke Expanded Disability Status Scale (EDSS) were used as measures of disease severity. Clinical relevance of the disease severity scores was analyzed using measures included in the Multiple Sclerosis Quality of Life Inventory. The MSFC and EDSS scores were correlated with self-reported employment status, the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and the Sickness Impact Profile (SIP). RESULTS: The MSFC and EDSS scores were strongly correlated (r = -0.80, P<.001). The MSFC scores were correlated with patient-reported physical functioning (SIP Physical Summary Scale: r = -0.71, P<.001; SF-36 Physical Component Score: r = -0.41, P<.001). The MSFC scores were significantly but more weakly correlated with emotional functioning (SIP Psychosocial Summary Scale: r = -0.34, P<.001). After controlling for EDSS scores, there were significant residual correlations between the MSFC scores and measures of health-related quality of life, suggesting that the MSFC accounts for the variability in health-related quality of life measures not reflected by the EDSS. CONCLUSIONS: The observed strong correlations between MSFC scores and validated measures of self-reported quality of life indicate that the MSFC scores are clinically relevant. This study supports a recommendation by the National Multiple Sclerosis Society Task Force to use the MSFC as a clinical outcome measure.

Adult↗
PubMed2000

Modification of the Penlon Nuffield 200 series ventilator and IPPV with a laryngeal mask airway.

There is a risk of regurgitation if a laryngeal mask airway is used with intermittent positive pressure ventilation. The lower the pressure gradient between airway and stomach, the less will be the likelihood of stomach insufflation with gas and consequent regurgitation. A flow generator ventilator, such as the Penlon Nuffield 200 which achieves a peak pressure at the end of inspiration at any given tidal volume, is likely to produce a higher peak airway pressure than a pressure generator. Replacing the expiratory valve by a venturi gives a preferable flow pattern with an inspiratory pressure plateau. At equal tidal volumes, the venturi modification provided a 10% lower inflation pressure (standard deviation 6%, P < 0.01) and a 1.8% smaller leak (P < 0.05) past the laryngeal mask airway. The same comparison but using identical inflation pressures, gave 8% larger tidal volumes (standard deviation 5.1%, P < 0.01) and a 2% smaller leak (P < 0.01) past the laryngeal mask airway.

Air Pressure↗
PubMed2000

Variable expression of cathepsin B and D correlates with highly invasive and metastatic phenotype of oral cancer.

The expression levels of cathepsins B, D, and L in oral cancer surgical specimens were determined using immunocytochemical analysis. Cathepsins B and D are frequently overexpressed in squamous cell carcinomas, whereas their overexpression was less frequent in verrucous carcinoma and basaloid squamous cell carcinomas. Elevated level of cathepsin B in oral carcinomas was significantly associated with advanced tumor stage (P < .05) and poor histologic malignancy grade (P < .001). Increased expression of cathepsin D correlated significantly with the presence of metastasis (P < .05), poor histologic malignancy grade (P < .001), and high proliferation rate (P < .05). Cathepsin L was less frequently overexpressed in oral cancers than cathepsin B and D. These findings indicate that there is a strong cause/effect relationship between the expression levels of cathepsin B and D in oral cancers and their local invasive and metastatic growth patterns. Thus, cathepsins B and D are useful prognostic markers as well as promising gene therapy targets for oral cancer.

Adult↗
PubMed2000

A meta-analysis of methylprednisolone in recovery from multiple sclerosis exacerbations.

Despite recent advances in multiple sclerosis treatment, patients experience relapses for which standard treatment remains glucocorticosteroids (GCS). However, there is limited information comparing doses or routes of administration for different GCS types or the benefit of GCS compared to natural recovery. Currently, high dose (HD) methylprednisolone (MP) is the preferred therapy. We conducted meta-analyses of published studies assessing MP at different doses and in comparison to other steroid products or no treatment. Relevant studies were identified through predetermined processes and five articles met the inclusion criteria. Three studies compared HD MP to placebo; two studies compared the effect of HD MP and low dose (LD) MP; only one accepted report compared HD MP to another GCS. This report could not be included in a meta-analysis. The meta-analysis of HD MP vsplacebo studies indicated a mean treatment difference of 0.76 in Expanded Disability Status Score (EDSS) changes from baseline. The meta-analysis of HD and LD MP demonstrated no difference in EDSS change. Despite these rather obvious findings, these meta-analyses have been valuable in identifying further research questions. We recommend studies to determine optimum benefit related to dosage, timing for starting therapy and the most appropriate GCS type. Given the advances in MS therapeutics, these studies will have to include patients on additional disease modifying therapy. Multiple Sclerosis (2000) 6 267 - 273

Disability Evaluation↗