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Biomedical subjects

A J Muir

Publications and source records attributed to A J Muir.

8 recordsLinked to original sources
PubMed2003

A case of electrical storm in a liver transplant patient.

Electrical storm has not been well described in liver transplant patients. We present a case of sympathetically mediated recurrent ventricular fibrillation in a young patient transplanted for acute Wilson's disease. This case highlights the role of the sympathetic nervous system in causing electrical storm and it demonstrates the ability of beta-blocking agents to terminate the event. In young liver transplant patients, beta-blocking agents should be considered for therapy of perioperative electrical storm if there is no known structural or coronary heart disease and when there are no risk factors for, or evidences of, torsades de pointes.

Adolescent↗
PubMed2001

Localization of cell wall polysaccharides in nonarticulated laticifers of Asclepias speciosa Torr.

Asclepias speciosa Torr. has latex-containing cells known as nonarticulated laticifers. In stem sections of this species, we have analyzed the cell walls of nonarticulated laticifers and surrounding cells with various stains, lectins, and monoclonal antibodies. These analyses revealed that laticifer walls are rich in (1-->4) beta-D-glucans and pectin polymers. Immunolocalization of pectic epitopes with the antihomogalacturonan antibodies JIM5 and JIM7 produced distinct labeling patterns. JIM7 labeled all cells including laticifers, while JIM5 only labeled mature epidermal cells and xylem elements. Two antibodies, LM5 and LM6, which recognize rhamnogalacturonan I epitopes distinctly labeled laticifer walls. LM6, which binds to a (1-->5) alpha-arabinan epitope, labeled laticifer walls more intensely than walls of other cells. LM5, which recognizes a (1-->4) beta-D-galactan epitope, did not label laticifer segments at the shoot apex but labeled more mature portions of laticifers. Also the LM5 antibody did not label cells at the shoot apical meristem, but as cells grew and matured the LM5 epitope was expressed in all cells. LM2, a monoclonal antibody that binds to beta-D-glucuronic acid residues in arabinogalactan proteins, did not label laticifers but specifically labeled sieve tubes. Sieve tubes were also specifically labeled by Ricinus communis agglutinin, a lectin that binds to terminal beta-D-galactosyl residues. Taken together, the analyses conducted showed that laticifer walls have distinctive cytochemical properties and that these properties change along the length of laticifers. In addition, this study revealed differences in the expression of pectin and arabinogalactan protein epitopes during shoot development or among different cell types.

Apocynaceae↗
PubMed2001

Reducing medication regimen complexity: a controlled trial.

OBJECTIVE: To determine if a visual intervention (medication grid) delivered to physicians can reduce medication regimen complexity. DESIGN: Nonrandomized, controlled trial. SETTING: Veterans Affairs medical center. PATIENTS/PARTICIPANTS: Eight hundred thirty-six patients taking at least 5 medications at the time of admission and the 48 teams of physicians and students on the general medicine inpatient service. INTERVENTION: For intervention patients, a medication grid was created that displayed all of the patients' medicines and the times of administration for 1 week. This grid was delivered to the admitting resident soon after admission. MEASUREMENTS AND MAIN RESULTS: For the patients of each team of physicians, we calculated the change in the average number of medications and doses from admission to discharge. The number of medications in the intervention group decreased by 0.92 per patient, and increased by 1.65 in the control group (P <.001). The mean number of doses per day in the intervention group decreased by 2.47 per patient and increased by 3.83 in the control group (P <.001). CONCLUSIONS: This simple intervention had a significant impact on medication regimen complexity in this population. Apparently, physicians were able to address polypharmacy when the issue was brought to their attention.

Adult↗
PubMed2001

A prospective evaluation of health-related quality of life after ileal pouch anal anastomosis for ulcerative colitis.

OBJECTIVES: The ileal pouch anal anastomosis is a safe and effective procedure but is also associated with pouchitis, small bowel obstruction, and incontinence. We prospectively evaluated the health-related quality of life using generic and disease-specific measures in a cohort of patients with ulcerative colitis undergoing ileal pouch anal anastomosis. METHODS: Health-related quality of life measures included the Time Trade-off, Rating Form of IBD Patient Concerns, and the Short-Form 36. Assessments occurred preoperatively and 1, 6, and 12 months postoperatively. RESULTS: Time Trade-off scores had significantly improved at the 1-month postoperative assessment and approached perfect health at the 12-month postoperative assessment. The Rating Form of IBD Patient Concerns revealed a significant reduction in patient concerns at 1 month, and this difference persisted at 6 and 12 months. Seven of the eight subscales of the Short-Form 36 revealed improved health-related quality of life postoperatively. CONCLUSIONS: Health-related quality of life improved after ileal pouch anal anastomosis when assessed with both generic and disease-specific measures. Improvements were observed as early as 1 month postoperatively. These results may guide patients and physicians as they consider and prepare for the impact of ileal pouch anal anastomosis.

Adult↗
PubMed2000

The natural history of hepatitis C viral infection.

Although early data suggested that chronic hepatitis C virus infection carried little risk, studies with longer duration of infection have reported concerning results. Of patients with acute infection, approximately 80% will develop chronic infection. The greatest risk of morbidity comes with cirrhosis and the resulting increased risk of hepatocellular carcinoma. The true risk of progression to cirrhosis, however, has emerged as an area of controversy. Both host and viral factors seem to impact susceptibility to chronic infection, cirrhosis, and hepatocellular carcinoma. Hepatitis C virus has become the most common indication for liver transplantation, but the infection routinely recurs and may have a more aggressive course after transplantation. Given that current treatment options for hepatitis C virus infection are clearly not optimal, informed decisions regarding treatment require an in depth understanding of the natural history.

Acute Disease↗
PubMed1996

The V3 domain of SIVmac251 gp120 contains a linear neutralizing epitope.

Antisera to 21 synthetic peptides containing hydrophilic sequences of simian immunodeficiency virus strain mac251 (SIVmac251) gp120 and gp32 were tested for the ability to neutralize SIVmac251. Goat antisera raised to peptides SP-1 and SP-1V containing the carboxy-terminal portion of the V3 domain of SIVmac251 gp120 between amino acids 327 and 339 inhibited syncytium formation (90% inhibition at a 1/1024 dilution) and cell killing of CEMx174 cells by SIVmac251 (50%) inhibition of cell killing at a dilution of 1/5832), SIVDeltaB670 (1/568), and SIVsmH4 (1/740). Neutralizing antibodies to SIVmac251, SIVDeltaB670, and SIVsmH4 could be adsorbed by peptides containing a neutralizing V3 sequence of SIVmac251 gp120 (GLVFHSQPIND, amino acids 329-339) but not by peptides lacking this sequence. This V3 neutralizing region corresponds to a homologous V3 neutralizing site within HIV-2 gp120 reported by Björling et al. 1991, Proc. Natl. Acad. Sci. USA 88, 6082-6086, 1994, J. Immunol. 152, 1952-1959). Antibodies in 20 of 31 sera obtained from rhesus macaques infected with SIVmac251 reacted with a peptide containing the entire V3 sequence of SIVmac251 gp120, whereas no sera contained antibodies reacting with the V3 neutralizing site between amino acids 329 and 339. Low levels of antibody-mediated recognition and subsequent lack of selective pressure against this linear V3 neutralizing site might in part explain why this region is not a dominant neutralizing site and also why sequences within V3 do not vary during the course of SIV infection.

Amino Acid Sequence↗
PubMed1992

Mapping of homologous, amino-terminal neutralizing regions of human T-cell lymphotropic virus type I and II gp46 envelope glycoproteins.

Twelve synthetic peptides containing hydrophilic amino acid sequences of human T-cell lymphotropic virus type I (HTLV-I) envelope glycoprotein were coupled to tetanus toxoid and used to raise epitope-specific antisera in goats and rabbits. Low neutralizing antibody titers (1:10 to 1:20) raised in rabbits to peptides SP-2 (envelope amino acids [aa] 86 to 107), SP-3 (aa 176 to 189), and SP-4A (aa 190 to 209) as well as to combined peptide SP-3/4A (aa 176 to 209) were detected in the vesicular stomatitis virus-HTLV-I pseudotype assay. Higher-titered neutralizing antibody responses to HTLV-I (1:10 to 1:640) were detected with pseudotype and syncytium inhibition assays in four goats immunized with a combined inoculum containing peptides SP-2, SP-3, and SP-4A linked to tetanus toxoid. These neutralizing anti-HTLV-I antibodies were type specific in that they did not inhibit HTLV-II syncytium formation. Neutralizing antibodies in sera from three goats could be absorbed with peptide SP-2 (aa 86 to 107) as well as truncated peptides containing envelope aa 90 to 98, but not with equimolar amounts of peptides lacking envelope aa 90 to 98. To map critical amino acids that contributed to HTLV-I neutralization within aa 88 to 98, peptides in which each amino acid was sequentially replaced by alanine were synthesized. The resulting 11 synthetic peptides with single alanine substitutions were then used to absorb three neutralizing goat antipeptide antisera. Both asparagines at positions 93 and 95 were required for adsorption of neutralizing anti-HTLV-I antibodies from all three sera. Peptide DP-90, containing the homologous region of HTLV-II envelope glycoprotein (aa 82 to 97), elicited antipeptide neutralizing antibodies to HTLV-II in goats that were type specific. In further adsorption experiments, it was determined that amino acid differences between homologous HTLV-I and HTLV-II envelope sequences at HTLV-I aa 95 (N to Q) and 97 (G to L) determined the type specificity of these neutralizing sites. Thus, the amino-terminal regions of HTLV-I and -II gp46 contain homologous, linear, neutralizing determinants that are type specific.

Amino Acid Sequence↗