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Biomedical subjects

M Carey

Publications and source records attributed to M Carey.

At least 91 records · Page 5Linked to original sources
PubMed1996

T lymphocyte mediated protection against facultative intracellular bacteria.

Acquired immunity against intracellular bacteria is T cell dependent. T cells play a major role in protection against intracellular bacteria, but bacterial antigens recognized by T cells have been studied less extensively than bacterial antigens recognized by B cells. Using T lymphocytes from animals immunized against Brucella abortus, we have screened a bacterial genomic library for genes encoding antigens recognized by T cells. Lymphocytes that proliferated to B. abortus proteins were characterized for phenotype and cytokine activity. Bovine and murine lymphocytes recognized common bacterial antigens and possessed similar cytokine profiles, suggesting an analogous immune response in these two animal species. In vivo protection afforded by a particular cell type is dependent on the bacterial antigens presented and mechanisms of antigen presentation. MHC class I and class II gene knockout animals infected with B. abortus have demonstrated that protection to B. abortus is especially dependent on CD8+ T cells. Knowing the cells required for protection, vaccines can be designed to elicit the protective subset of lymphocytes. Currently, we are testing several recombinant B. abortus proteins using different immunization strategies. Finally, bacterial genes activated following intracellular phagocytosis are being examined using a novel, reporter system adapted to B. abortus.

Animals↗
PubMed1996

Effects of positive airway pressure on upper airway dilator muscle activity and ventilatory timing.

To determine upper airway (UA) and ventilatory responses to nasal continuous positive airway pressure (CPAP) and expiratory positive airway pressure (EPAP), we quantitated changes in alae nasi (AN) and genioglossus (GG) electromyographic (EMG) activity, ventilatory timing, and end-expiratory lung volume (EELV) at various levels of CPAP and EPAP in six normal subjects during wakefulness and in seven during sleep. The same measurements were also made before and after UA anesthesia in six normal subjects during wakefulness. During both wakefulness and sleep, CPAP application significantly increased EELV and decreased AN and GG EMG activities. In contrast, EPAP significantly increased EMG activities of both muscles while also increasing EELV during wakefulness. The EMG responses were less marked during sleep. Anesthesia of the UA abolished the EMG responses to CPAP but not to EPAP. These results suggest that, in normal subjects, CPAP application causes a reflex reduction in UA dilator muscle activity mediated by UA sensory receptors. In contrast, EPAP increases UA dilator muscle activity, with the response mediated by conscious influences or reflexes arising outside of the UA.

Adolescent↗
PubMed1995

A general mechanism for transcriptional synergy by eukaryotic activators.

One of the important regulatory concepts to emerge from studies of eukaryotic gene expression is that RNA polymerase II promoters and their upstream activators are composed of functional modules whose synergistic action regulates the transcriptional activity of a nearby gene. Biochemical analysis of synergy by ZEBRA, a non-acidic activator of the Epstein-Barr virus (EBV) lytic cycle, showed that the synergistic transcriptional effect of promoter sites and activation modules correlates with assembly of the TFIID:TFIIA (DA) complex in DNase I footprinting and gel shift assays. The activator-dependent DA complex differs from a basal DA complex by its ability to bind TFIIB stably in an interaction regulated by TATA-binding protein-associated factors (TAFs). TFIIB enhances the degree of synergism by increasing complex stability. Similar findings were made with the acidic activator GAL4-VP16. Our data suggest a unifying mechanism for gene activation and synergy by acidic and non-acidic activators, and indicate that synergy is manifested at the earliest stage of preinitiation complex assembly.

DNA-Binding Proteins↗
PubMed1995

Protease footprinting reveals a surface on transcription factor TFIIB that serves as an interface for activators and coactivators.

Transcriptional stimulation by the model activator GAL4-VP16 (a chimeric protein consisting of the DNA-binding domain of the yeast activator GAL4 and the acidic activation domain of the herpes simplex virus protein VP16) involves a series of poorly understood protein-protein interactions between the VP16 activation domain and components of the RNA polymerase II general transcription machinery. One of these interactions is the VP16-mediated binding and recruitment of transcription factor TFIIB. However, TATA box-binding protein (TBP)-associated factors (TAFs), or coactivators, are required for this interaction to culminate in productive transcription complex assembly, and one such TAF, Drosophila TAF40, reportedly forms a ternary complex with VP16 and TFIIB. Due to TFIIB's central role in gene activation, we sought to directly visualize the surfaces of this protein that mediate formation of the ternary complex. We developed an approach called protease footprinting in which the broad-specificity proteases chymotrypsin and alkaline protease were used to probe binding of 32P-end-labeled TFIIB to GAL4-VP16 or TAF40. Analysis of the cleavage products revealed two regions of TFIIB protected by VP16 from protease attack, one of which overlapped with a region protected by TAF40. The close proximity of the VP16 and TAF40 binding sites on the surface of TFIIB suggests that this region could act as a regulatory interface mediating the effects of activators and coactivators on transcription complex assembly.

Amino Acid Sequence↗
PubMed1995

The requirement for the basal transcription factor IIE is determined by the helical stability of promoter DNA.

The role of the basal transcription factor TFIIE was investigated in RNA polymerase II transcription reactions reconstituted with purified proteins. Using negatively supercoiled templates, which circumvent the requirement for TFIIH, we observed that transcription from the adenovirus major-late (ML) core promoter is more dependent on TFIIE than transcription from the adenovirus E4 (E4) or mouse mammary tumor virus (MMTV) promoters. For all three promoters, an increase in the ionic strength of the reaction mixtures led to an increased dependence on TFIIE. Analysis of hybrid ML/MMTV promoters showed that the region encompassing the start site, from -10 to +10, dictates this dependence. Transcription from a relaxed E4 template with a pre-melted -8 to +2 region was completely independent of both TFIIE and TFIIH. We propose that on negatively supercoiled templates TFIIE can facilitate promoter melting.

Adenoviruses, Human↗
PubMed1995

Diabetes guidelines, outcomes, and cost-effectiveness study: a protocol, prototype, and paradigm.

It is a milestone for our profession to have practice guidelines tested in a clinical trial that also provides cost-effectiveness data. Dietetics practitioners now have a model for studies examining MNT in other disorders and diseases. We also have an array of questions that can be asked in future studies. The challenges include examining the long-term management of diseases using MNT; determining changes in quality-of-life issues; and segmenting subjects according to variables likely to affect outcomes, such as duration of the disease. As a result of this and other studies related to diabetes (both completed and in progress), millions of people with NIDDM will be guided to achieve the best glycemic control possible within the framework of their lifestyles. The results of the DCCT may have implications for persons with NIDDM (18), as well as for dietitians (8). The UK Prospective Diabetes Study results should be released in the near future (19), and the VA Cooperative Study on Glycemic Control and Complications in Type II Diabetes (20) is examining intensive therapy for this population. Each of these studies emphasizes a treatment approach that places management of the disease in the hands of the client. This approach clearly is a paradigm shift: no longer are we talking about "diabetic diets." But then, maybe we just need to read a little history. In 1906, Hutchison (21) wrote," ... there is no such thing as 'a diabetic diet.'" And think about the information (or lack thereof) available to him.

Blood Glucose↗
PubMed1995

Benefits and costs of medical nutrition therapy by registered dietitians for patients with hypercholesterolemia. Massachusetts Dietetic Association.

The Massachusetts Dietetic Association implemented a statewide retrospective quality assurance audit to determine the effectiveness and cost of medical nutrition therapy in patients with hypercholesterolemia (> 5.20 mmol/L). Hypercholesterolemia is a major risk factor for coronary artery disease (CAD). Data were collected at 23 sites from 285 outpatients seen by a registered dietitian for a minimum of two visits. Patients taking lipid-lowering medications were excluded. Of the 285 patients, 108 (38%) were men and 177 (62%) were women. The mean age was 51.4 years (range = 22 to 79 years). Results showed that the mean reduction in serum cholesterol level was 8.6%, which translates to a decrease of approximately 17.2% in risk of CAD. Forty-five percent of the total population showed an 11% or greater reduction in serum cholesterol levels. Reduction in serum cholesterol levels correlated with increased time spent with a dietitian (r = .188, P < .001). The mean cost for nutrition intervention with a dietitian was $163 (a mean of four visits). In contrast, the estimated annual cost of treatment for patients with hypercholesterolemia using drug therapy is $1,450. A 1993 report calculated the annual cost of treating heart disease in the United States to be $80 billion. Medical nutrition therapy should be considered the initial, effective, and low-cost approach in the management of patients with mild to moderate hypercholesterolemia.

Adult↗
PubMed1994

A heteroduplex template circumvents the energetic requirement for ATP during activated transcription by RNA polymerase II.

Unlike most eukaryotic and prokaryotic RNA polymerases, promoter-specific transcription by RNA polymerase II requires hydrolysis of the ATP beta-gamma phosphoanhydride bond. Here we show that a template containing a 10-base pair DNA mismatch encompassing the start site circumvents this requirement such that the non-hydrolyzable ATP analogues, ATP gamma S (adenosine 5'-O-(thiotriphosphate)) and AMP-PNP (adenyl-5'-yl imidodiphosphate), support both basal and GAL4-VP16-activated transcription in a reconstituted HeLa cell in vitro transcription system. The results imply that ATP regulates either opening of the template at the start site or a closely associated step.

Adenosine Triphosphate↗
PubMed1994

The role of activators in assembly of RNA polymerase II transcription complexes.

The past year has provided new insights into the biochemical mechanism of gene activation. Key discoveries include the finding that TFIIA plays an important regulatory role in transcription complex assembly, the TBP-associated factors are direct targets of at least two classes of activator, and a largely pre-assembled transcription complex has been isolated from yeast cells, challenging the step-wise assembly pathway. This review also presents an update on the argument that TFIIB is the target of VP16 and insights into the energetic role of ATP in RNA polymerase II initiation.

Adenosine Triphosphate↗
PubMed1994

Modulating the potency of an activator in a yeast in vitro transcription system.

The intrinsic stimulatory potential or potency of a eukaryotic gene activator is controlled by the interaction between the activation domain and the transcriptional machinery. To further understand this interaction, we undertook a biochemical study to identify parameters that could be used to modulate activator potency. We considered how varying the number of activation domains, their flexibility, and the number of promoter sites affects potency in a yeast nuclear extract. The effects of GAL4 derivatives bearing either one, two, or four herpes simplex virus VP16 activation domains (amino acids 413 to 454) were measured on DNA templates containing one or two GAL4 sites in a Saccharomyces cerevisiae nuclear extract. We found that multimerized VP16 activation domains acted synergistically to increase the potency of the activators. The spacing between the activation domains was critical, such that the increased flexibility imparted by a protein linker contributed to increased activator potency. With highly potent activators, the levels of transcription stimulated on a single site were saturating, whereas the stimulatory effect of weaker activators increased with the number of sites. We discuss how these biochemical studies relate to the mechanism of gene activation and synergy in a yeast in vitro system.

Cell Nucleus↗
PubMed1993

The association between beta-agonist use and death from asthma. A meta-analytic integration of case-control studies.

OBJECTIVES: The purpose of this investigation was to provide an empirical summary of the evidence regarding the association between beta-agonist use and death from asthma. This effort integrated the results of case-control studies that examined the use of beta-agonists among asthmatic patients who died and the use of beta-agonists among asthmatic patients who did not die. The possible moderating effects of patient sample age and mode of delivery (oral, metered-dose inhaler, and nebulizer) were also examined. DATA SOURCES: An on-line computer search (using MEDLINE) was conducted using the key words beta-agonist and asthma. This search was supplemented by ancestry and descendency approach searches. Studies that were available as of April 1992 were eligible for inclusion in this integration. STUDY SELECTION: Studies were included if they reported the precise numbers of cases and controls who did and did not use a beta-agonist. A total of six case-control studies comprising 15 separate tests of the relation between beta-agonist use and death from asthma and data for 364 cases and 1388 controls were included. DATA EXTRACTION: The 2 (case vs control) x 2 (did vs did not use beta-agonist) designs allowed for direct derivation of a chi 2 statistic that tested the association between beta-agonist use and death from asthma. Mode of delivery and average age of sample were also coded. DATA SYNTHESIS: Statistical integration revealed a significant, although extremely weak, relation between beta-agonist use and death from asthma (z = 3.996; P = .000075; mean r = .055). This relation emerged only when beta-agonists were administered with a nebulizer (z = 4.481; P = .0000038; mean r = .103). There was no association between beta-agonist use and death when beta-agonists were administered by metered-dose inhaler (z = 1.194; P = .11; mean r = .031) or orally (z = 1.247; P = .1; mean r = .031). Adults were more likely than adolescents to evidence the association between beta-agonist use and death. CONCLUSIONS: These results document the extremely small magnitude of the relation between beta-agonist use and death from asthma. Furthermore, these results specify that the weak relation between beta-agonist use and death from asthma may really be restricted to the delivery of beta-agonists with a nebulizer. These findings suggest that the headlines that followed the report by Spitzer et al (1992) were misleading.

Administration, Inhalation↗
PubMed1993

Patient response to laryngeal mask insertion after induction of anaesthesia with propofol or thiopentone.

The response to insertion of the laryngeal mask airway (LMA) following either propofol 2.5 mg.kg-1 or thiopentone 5 mg.kg-1 was assessed in two groups of patients. The purpose of the study was to ascertain which of these two induction agents provided the better conditions for insertion of the LMA. Anaesthesia was induced by propofol in 35 patients and by thiopentone in 37. Following induction, ventilation was assisted for two minutes using 50% oxygen and nitrous oxide and 2% isoflurane, before insertion of the LMA. The presence of gagging, coughing, laryngospasm and movement was noted and graded. Thiopentone was associated with an adverse response in 76% of patients, compared with propofol in 26% (P < 0.01). Gagging, laryngospasm and head movement were more common using thiopentone (P < 0.01, P < 0.05 and P < 0.05 respectively) and in 11% (P < 0.05) of the thiopentone group insertion of the LMA was impossible due to inadequate relaxation. We conclude that, using these doses, propofol is superior to thiopentone as an induction agent for insertion of the laryngeal mask airway.

Adult↗
PubMed1993

Treatment-related fatigue and serum interleukin-1 levels in patients during external beam irradiation for prostate cancer.

To define changes in sleep and subjective fatigue associated with localized radiation treatment, and to determine their relationship to interleukin-1B (IL-1), we prospectively followed 15 men, none of whom were depressed during 8 wk of radiation treatment for localized prostate cancer. Each patient rated fatigue daily on a visual analogue scale, recorded hours slept, and completed the Beck Depression Inventory weekly. Serum IL-1, taken at baseline and Fridays, was measured by quantitative enzyme immunoassay. Ranked weekly mean fatigue scores for each subject increased at week 4 (mean, 17 fractions, 1.8 Gy) then plateaued and rose in weeks 6 and 7. In week 6, the last week of full volume radiation, subjects slept most compared to all other weeks including week 7 when treatment was coned down. Ranked serum IL-1 tended to rise between weeks 1 and 4, as fatigue scores rose. These data suggest that localized radiation treatment is associated with increased fatigue and sleep requirement independent of depressive symptoms. Relative serum IL-1 changes may be one signal for the systemic reaction and subjective fatigue associated with the acute effects of radiation.

Aged↗