Search PubMed⌕ Search

Biomedical subjects

M Delaney

Publications and source records attributed to M Delaney.

At least 19 recordsLinked to original sources
PubMed2001

Expression and function of chemokine receptors on human thymocytes: implications for infection by human immunodeficiency virus type 1.

The presence or absence of the receptor CD4 and the coreceptors CCR5 and CXCR4 restrict the cell tropism of human immunodeficiency virus type 1 (HIV-1). Despite the importance of thymic infection by HIV-1, conflicting reports regarding the expression of HIV-1 coreceptors on human thymocytes have not been resolved. We assayed the expression and function of the major HIV-1 coreceptors, CCR5 and CXCR4, as well as CCR4 and CCR7 as controls, on human thymocytes. We detected CCR5 on 2.5% of thymocytes, CXCR4 on 53% of the cells, and CCR4 on 16% and CCR7 on 11% of human thymocytes. Moreover, infection by R5 HIV-1 did not significantly induce expression of CCR5. We found that two widely used anti-CCR5 monoclonal antibodies cross-reacted with CCR8, which may account for discrepancies among published reports of CCR5 expression on primary cells. This cross-reactivity could be eliminated by deletion of amino acids 2 through 4 of CCR8. Chemotaxis assays showed that SDF-1, which binds CXCR4; MDC, which binds CCR4; and ELC, which binds CCR7, mediated significant chemotaxis of thymocytes. In contrast, MIP-1beta, whose receptor is CCR5, did not induce significant chemotaxis. Our results indicate that CXCR4, CCR4, CCR7, and their chemokine ligands may be involved in thymocyte migration during development in the thymus. CCR5 and its ligands, however, are likely not involved in these processes. Furthermore, the pattern of CCR5 and CXCR4 expression that we found may explain the greater susceptibility of human thymocytes to infection by HIV-1 isolates capable of using CXCR4 in cell entry compared to those that use only CCR5.

Amino Acid Sequence↗
PubMed1999

"Teach 1, do 1 ... better": superior communication skills in senior medical students serving as standardized patient--examiners for their junior peers.

PURPOSE: To see if senior medical students who had served as standardized patients (SP) demonstrated improvement in their own interpersonal communication skills. METHOD: From George Washington School of Medicine's class of 1996, 154 fourth-year students took a clinical practice examination that used professional SPs. Within the preceding six months, 28 of these students had been SP-examiners in similar examinations for first- and second-year medical students. The professional SPs rated the fourth-year examinees using checklists that measured five dimensions of interpersonal communication skills. Four of these five dimensions were identical to those measured on the examinations for which the fourth-year students had served as SPs. Hypothesizing that the SP-experienced seniors would outscore their inexperienced classmates on those four dimensions, but not on the fifth, the authors analyzed the fourth-year students' scores. P values were computed by the F test from a two-way analysis of variance. RESULTS: As predicted, the group with prior SP experience significantly outscored their inexperienced colleagues in each of the four expected dimensions of interpersonal communication skills, with p values ranging from .000 to .023. The score differential in these dimensions ranged from 3.8 to 11.8 percentage points. As further predicted, there was no significant difference between the scores of the two groups on the fifth dimension. CONCLUSION: Compared with their inexperienced peers, senior medical students with prior SP experience consistently demonstrated superior scores when their own communication skills were tested in a similar manner. The U.S. Medical Licensing Examinations propose to incorporate SP clinical examinations; in response, medical schools will use more SP examinations in their own curricula. Such examinations are expensive when using professional standardized patients; the authors believe that an SP program using senior medical students will prove an attractive alternative. Such programs may have the added advantage of making better communicators of senior medical student teachers as well as the students they teach.

Communication↗
PubMed1999

The utility of pacemaker evoked T wave amplitude for the noninvasive diagnosis of cardiac allograft rejection.

Previous work suggested that pacemaker evoked T wave amplitude (ETWA) may be a sensitive noninvasive marker of cardiac allograft rejection. A Topaz QT sensing rate responsive pacemaker (Vitatron Medical) was implanted at transplantation using epicardial ventricular leads in 45 recipients (35 males; median age 51 years, range 20-63). The median duration of follow-up was 129 days (range 4-327). The ETWA at a paced rate of 100 beats/min was measured daily during hospitalization and at each outpatient attendance (900 readings). Endomyocardial biopsies were at routine intervals or when otherwise clinically indicated (257 biopsies with concurrent ETWA data). There were 58 episodes of rejection > or = grade 3a in 28 patients. The biopsies were classed as either no rejection (grade < 3a) or rejection requiring treatment (grade > or = 3a). The median normalized ETWA was 100.8% (range 24.6-239.7) without rejection and 89.9% (17.0-189.7) with rejection (Mann-Whitney U Test: P = 0.028). The performance of ETWA monitoring as a diagnostic test for the individual recipient was evaluated with exponentially weighted moving average quality control charts. For the diagnosis of all rejection episodes, ETWA monitoring had a sensitivity of 55%, a specificity of 62%, a positive predictive value of 30%, and negative predictive value of 83%. It is concluded that although analysis of pooled data showed a significant reduction in normalized ETWA with biopsy proven rejection, ETWA monitoring requires further refinement to improve sensitivity before it can be considered a clinically useful technique for the non-invasive diagnosis of cardiac allograft rejection in individual recipients.

Adult↗
PubMed1995

Effect of estradiol 17 beta on pressor responses of rat mesenteric bed to norepinephrine, K+, and U-46619.

We reinvestigated the effect of estradiol 17 beta on the responses of adrenergic and nonadrenergic vasoconstrictors characterized it in terms of steroid specificity, time course, and the role of classic estrogen receptors. We evaluated the effect of estradiol 17 beta on the pressor responses of isolated perfused rat mesenteric vascular bed (McGregor's preparation). Estradiol 17 beta (7-700 nM) significantly increased the pressor response to bolus applications of norepinephrine (NE) (p < 0.05). However, estradiol 17 beta did not significantly increase the responses to endogenous NE release induced by electrical field stimulation. Other steroids, testosterone, and the 17 alpha isomer of estradiol (7 and 700 nM) were ineffective. Estradiol 17 beta (700 nM) also significantly increased the maximum pressor response of rat mesenteric preparation to both the prostaglandin endoperoxide analogue U-46619 and to K+. The potentiation by estradiol 17 beta of mesenteric vasoconstriction elicited by NE, K+, and U-46619 was rapid (2-8 min), suggesting that a nuclear receptor may not be involved. This notion received further support in that significant potentiation of the NE-induced pressor response was also observed with estradiol 17 beta conjugated to albumin (700 nM), but not when electrical field stimulation was used. The conjugate increased the effect of all NE concentrations. Its effect was also more consistent (p < 0.01) than that elicited by free estradiol 17 beta. The dose-response curve was shifted to the left, and the maximum effect was increased. These data suggest that estradiol 17 beta may possess rapid nongenomic actions unrelated to nuclear receptor binding and gene transcription.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

Detection of the heat-stable toxin coding gene (ST-gene) in enterotoxigenic Escherichia coli: development of a colour amplified PCR detection system.

Screening biological samples using the polymerase chain reaction (PCR) has obvious advantages compared with current molecular analytical methods based on gel electrophoresis and/or hybridisation, both of which are expensive and time-consuming, therefore the development of a PCR assay format that is applicable to large sample numbers and that can readily use equipment commonly found in diagnostic laboratories would be advantageous. This report describes the development of a colour amplified PCR detection system which is simple in design and could be universally applied to the detection of any DNA template. As an example, the system has been applied in the detection of the heat-stable toxin coding gene (ST-gene) from enterotoxigenic Escherichia coli (ETEC). The assay is sensitive, detecting 10 fg of a purified DNA template and 270 cfu of an ST-gene-positive ETEC strain.

Bacterial Toxins↗
PubMed1994

AIDS research.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Ocular injuries and diseases at a combat support hospital in support of Operations Desert Shield and Desert Storm.

A retrospective review of all emergency department visits to a combat support hospital (one of four combining to support 150,000 troops) during Operations Desert Shield and Desert Storm was conducted, and all medical records of patients with ocular complaints were analyzed. Ocular injury and/or disease accounted for 14% (108/767) of these visits to the emergency department. Of 108 patients with ocular complaints, corneal foreign bodies (18), ocular burns (14), and traumatic iritis (eight) were the most common injuries treated, while blepharitis and conjunctivitis (16) were the most common diseases. Nineteen (18%) of the 108 patients with ocular complaints were treated during support of the ground war in Iraq (13 were Iraqi prisoners). Ophthalmic injuries accounted for 13% (19/149) of all ground war casualties; however, eight individuals had associated injuries deemed more significant than those of ocular concern. This incidence continues the trend of earlier wars, which has demonstrated a steady increase in ocular injuries. Most US Army troops were issued protective goggles, but only three of 92 American patients wore them at the time of their injury and/or disease.

Emergencies↗
PubMed1993

19-Nor-corticosteroids in genetic hypertension. Effects of inhibitors of 11 beta, 18, 19-hydroxylase activity.

The long-term objective is to understand the role of the adrenal in altering systemic arterial blood pressure. This paper summarizes research on genetic hypertension in the rat and bears a relationship to several forms of human hypertension in which defects of steroid hydroxylases lead to increased secretion of mineralocorticoids other than aldosterone in genetic and experimental hypertension in rats. We demonstrated that 19-nor-corticosteroids are produced in excess in genetic and experimental hypertension in rats and man. We studied the enzymatic alteration responsible for excessive production of 19-nor-deoxycorticosterone (19-nor-DOC) in the salt-sensitive hypertensive rat S/JR. Biosynthesis of 19-nor-steroids involves hydroxylation of the C-19 methyl group. We characterized the adrenal 11 beta, 18,19-hydroxylase enzyme system in inbred salt-sensitive and resistant rats (R/JR). This system is capable of all three hydroxylations. The Km for 19-hydroxylation was different from S/JR and R/JR but was much greater for 11 beta- and 18-hydroxylation in both. This suggested that the catalytic site for 19-hydroxylation is different from that for 11 beta and 18. The S/JR adrenal enzyme binds the substrate with higher affinity than does the R/JR adrenal enzyme. We were unable to distinguish the cDNAs of the S/JR from the R/JR adrenal enzyme from bovine 11 beta-hydroxylase cDNA by restriction mapping. We were unable to demonstrate restriction length polymorphism. 19-Acetylenic DOC is an inhibitor which preferentially inhibits the 19-hydroxylation of DOC, and does not interfere with the 18- and 11 beta-hydroxylation. This inhibition leads to a reduction in blood pressure in the S/JR Dahl rat. We suggest that an S/JR 19-nor-DOC is involved in the development of salt-sensitivity and hypertension and that inhibition of its formation by acetylenic DOC and other aromatase and non-aromatase inhibitors is associated with reversal of these phenomena.

Animals↗
PubMed1993

Pigeon-breeder's lung. Extensive workup clarifies the clinical picture.

Pigeon-breeder's lung should be included in the differential diagnosis when patients present with interstitial lung disease or intermittent cough and dyspnea. No single test confirms the diagnosis. Rather, careful attention must be given to results of history taking, physical examination, pulmonary function and precipitin testing, chest radiography, and, if indicated, lung biopsy. Symptoms usually resolve when exposure to suspected antigens is avoided.

Adult↗