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Biomedical subjects

S Anderson

Publications and source records attributed to S Anderson.

At least 307 records · Page 17Linked to original sources
PubMed1994

Completing the clinical audit cycle: discharge medication.

Describes the process of clinical audit following the introduction of a revised discharge policy. Identifies three key indicators of success regarding hospital supply of discharge medication: the extent to which ward staff and patients have to make personal visits to the pharmacy; the extent to which nursing staff telephone the pharmacy to chase individual prescriptions; and the rate of written complaints from patients. All three measures increased substantially during the four months following the introduction of the policy, compared with the previous four-month period. An action plan focused on changing relevant behaviour of consultants, junior doctors, ward and nursing personnel, patients and pharmacy staff by means of increased awareness of the consequences of their actions. A follow-up study demonstrated substantial reductions in all three measures during a third four-month period.

Aftercare↗
PubMed1994

Phenotypic and functional analysis of bone marrow progenitor cell compartment in bone marrow failure.

Many laboratory findings have demonstrated that the haemopoietic stem cell compartment is defective in aplastic anaemia (AA). AA bone marrow (BM) and peripheral blood (PB) are profoundly deficient in colony-forming cells, and AA progenitors fail to proliferate in long-term assays even in the presence of an intact stroma. Our study was designed to characterize some quantitative and qualitative aspects of the progenitor cell defect in AA. Using flow cytometric analysis of BM from new AA patients and from those recovering after immunosuppressive therapy, we determined that the numbers of CD34+ and CD33+ cells were markedly decreased in AA. Although PB neutrophil counts did not correlate with BM CD34+ cell numbers in acute disease, there was an association between the overall severity of the disease and the degree of CD34+ cell reduction. A decrease in BM CD33+ cells was a common finding in MDS patients, but reduction in CD34+ cells was found only in some hypoplastic MDS cases. Sorting experiments demonstrated lower plating efficiency for purified CD34+ cells from AA BM in comparison to controls. Thus, diminished colony formation of total BM appeared to result from both quantitative and qualitative defects. Based on the association between increased cycling and c-kit receptor expression on CD34+ cells, we found that the mitotically active CD34+ cells bearing the c-kit antigen were reduced in AA. With clinical improvement, CD34+ and CD33+ cells increased in correlation with PB parameters, but they did not return to normal values. Sorted CD34+ cells from recovered patents showed improved plating efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Evidence that use of a second-generation hepatitis C antibody assay prevents additional cases of transfusion-transmitted hepatitis.

The aim of this study was to determine if using hepatitis C antibody (anti-HCV) enzyme immunoassay version 2.0 (EIA2) in addition to version 1.0 (EIA1) increased the safety of the blood supply. Blood non-reactive by anti-HCV EIA1 was transfused in 1990-92. Stored samples from 40098 units, donated prior to 13 March 1992 were later tested by EIA2. For donor units reactive for anti-HCV by EIA2, a recombinant immunoblot assay (RIBA2) was also carried out. In 63 cases, recipients of transfusions which were EIA2 negative or EIA2 reactive were tested for anti-HCV and elevated alanine aminotransferase (ALT) levels 9-12 months after transfusion; pretransfusion anti-HCV status of recipients was unknown. Among these multitransfused patients receiving units that were negative by both EIA1 and EIA2, 1/26 (4%) had anti-HCV. Among transfusion recipients of units negative by EIA1, but who received at least one unit reactive by EIA2, 4/37 recipients (11%) were anti-HCV reactive (P = 0.59). For the recipients of EIA2 reactive blood, when the donor unit was RIBA2 non-reactive, 0/23 recipients were reactive by anti-HCV. Among the recipients of a RIBA2 indeterminate unit, 1/10 recipients had anti-HCV, but for patients who received at least one RIBA2 reactive unit, 3/4 recipients had anti-HCV (P = 0.03). Hence, second-generation anti-HCV testing detected additional units capable of transmitting hepatitis C that were not detected by first-generation testing. However, RIBA2 is a more specific method than EIA2 for determining units capable of transmitting HCV.

Aged↗
PubMed1994

Altered renal vascular responses in the aging rat kidney.

Age-related renal functional changes may relate to alterations in the responsiveness to vasoconstrictors and vasodilators. Blood pressure and renal responses to angiotensin II (ANG II), endothelin-1 (ET), NG-nitro-L-arginine methyl ester (L-NAME), and to the ANG II receptor antagonist losartan were compared in young (3-mo-old) and older (15-mo-old) male rats. Baseline mean arterial pressure (MAP) values were slightly lower in the older rats, and glomerular filtration rate (GFR) and renal plasma flow (RPF) were higher. ANG II and ET induced comparable pressor responses in both groups but produced greater GFR and RPF reductions in the older rats. In contrast, the MAP, GFR, and RPF responses to L-NAME were exaggerated in aging rats. Losartan induced modest MAP reductions in both groups, and comparable renal vasodilatory responses. Thus the aging kidney exhibits exaggerated responses to systemic vasoconstrictor stimuli, whereas responsiveness to ANG II blockade is preserved but not enhanced. Whether or not this balance is further impaired later in the aging process remains to be determined.

Aging↗
PubMed1994

Glomerular adaptations with normal aging and with long-term converting enzyme inhibition in rats.

Normal aging is accompanied by renal functional and structural deterioration. To examine the hemodynamic and growth-related mechanisms of age-associated nephron loss, as well as the potential beneficial effects of antihypertensive therapy, studies were performed in normal aging Munich-Wistar rats, and in rats receiving long-term antihypertensive therapy with the converting enzyme inhibitor (CEI) enalapril. In protocol 1, rats were treated from the age of 3 mo. Compared with young rats, untreated old rats studied at 2.5 yr of age exhibited normal blood pressure but increased glomerular capillary pressure due to a reduction in afferent arteriolar resistance. Glomerular size increased proportionately to changes in body weight, while kidney weight increased to a lesser degree. Albuminuria rose significantly after 10 mo of age and was accompanied by development of modest, but significant, glomerular sclerosis. CEI therapy from the age of 3 mo lowered systemic and glomerular capillary pressures, did not affect glomerular size, and significantly ameliorated development of albuminuria and structural injury. In protocol 2, untreated rats were compared with a treated group in which enalapril therapy was delayed until the age of 1 yr, when albuminuria was already rising. Subsequent increases in albuminuria and development of sclerosis were significantly attenuated, although not entirely prevented. These findings suggest that hemodynamic maladaptations may contribute to age-related loss of renal function in the rat and that antihypertensive therapy may serve to delay this process.

Adaptation, Physiological↗
PubMed1994

Genetic and molecular ecotoxicology: a research framework.

Participants at the Napa Conference on Genetic and Molecular Ecotoxicology assessed the status of this field in light of heightened concerns about the genetic effects of exposure to hazardous substances and recent advancements in our capabilities to measure those effects. We present here a synthesis of the ideas discussed throughout the conference, including definitions of important concepts in the field and critical research needs and opportunities. While there were many opinions expressed on these topics, there was general agreement that there are substantive new opportunities to improve the impact of genetic and molecular ecotoxicology on prediction of sublethal effects of exposure to hazardous substances. Future studies should emphasize integration of genetic ecotoxicology, ecological genetics, and molecular biology and should be directed toward improving our understanding of the ecological implications of genotoxic responses. Ecological implications may be assessed at either the population or ecosystem level; however, a population-level focus may be most pragmatic. Recent technical advancements in measuring genetic and molecular responses to toxicant exposure will spur rapid progress. These new techniques have considerable promise for increasing our understanding of both mechanisms of toxicity on genes or gene products and the relevance of detrimental effects to individual fitness.

Animals↗
PubMed1994

Recombinant hemoglobin A produced in transgenic swine: structural equivalence with human hemoglobin A.

Recombinant human hemoglobin A produced by coexpressing human alpha and beta globin genes in swine, and purified from the lysate of transgenic swine has been subjected to detailed protein chemical analysis. These structural studies involving laser desorption mass spectrometry, separation of globin chains by RPHPLC, amino terminal sequence analysis of the isolated globin chains, the tryptic peptide mapping of the purified globin chains and the amino acid composition analysis of the purified tryptic peptides of globin chains have established the primary structural equivalence of the globin chains of the transgenic swine derived hemoglobin A with that of human hemoglobin A. These results demonstrate that the transgenic swine system correctly translates the human alpha and beta globin m-RNA; carries out the correct cotranslational processing of globin chains, and does not introduce any unwanted post translational modifications into the mature chains. Thus, the transgenic swine expression system is an excellent approach for the production of HbA for developing an effective hemoglobin based oxygen carrier.

Amino Acid Sequence↗
PubMed1994

Categorical data analysis of the effect on bull fertility of butylated hydroxytoluene addition to semen extenders prior to freezing.

Butylated hydroxytoluene is an antioxidant that has antiviral properties and sustains sperm viability during freezing and thawing. A field trial involving 11 bulls and 19,000 AI was conducted to determine whether addition of .5 mM butylated hydroxytoluene to whole milk extender during seminal processing affected bull fertility as estimated by nonreturn rates generated by cows bred to the bulls. Effects of bull, batch of semen nested within bull, treatment, and month of AI were studied. Nonreturn rates were recorded for each month for every bull, batch of semen (ejaculates pooled on a given day), and treatment combination. Because some bulls had < 6 batches of semen, the original experimental design was reduced to two smaller designs. Categorical data analysis with maximum likelihood estimation was used for analysis of nonreturn rates. The results from three models were used to interpret the data. The nonreturn rates were approximately 73.9% for the butylated hydroxytoluene treatment and 74.1% for the control. In all models, bull effect was significant, but batch, month of AI, and treatment had no effect on bull fertility. Addition of .5 mM butylated hydroxytoluene to whole milk extender during semen processing did not affect bull nonreturn rates.

Animals↗
PubMed1994

Biological properties of subpopulations of pluripotent hematopoietic stem cells enriched by elutriation and flow cytometry.

We have studied several features of pluripotent hematopoietic stem cells (PHSCs) and day-12 spleen colony-forming units (CFU-S) obtained from adult murine bone marrow. Single-cell suspensions of C57BL/6J mouse bone marrow were fractionated by counterflow centrifugal elutriation at flow rates (FR) of 15, 25, 30, and 35 ml/min, and with the rotor off (R/O). The fractions FR25 and FR35 contained approximately equal numbers of PHSC that could repopulate W/Wv mice. These PHSCs were further enriched by subtracting lineage-positive cells using monoclonal antibodies (MAb) and magnetic immunobeads. The resulting lineage-negative cells (Lin-) were then stained with a MAb for the c-kit receptor and sorted by flow cytometry. Both subsets were fractionated into cells expressing high (bright) (c-kitBR), low (dull) c-kitDULL and no (negative, c-kitNEG) c-kit receptor. As few as 100 to 200 c-kitBR cells could repopulate the entire thymus and bone marrow in W/Wv mice. No PHSCs were present in the c-kitDULL and c-kitNEG fractions. We assayed fresh bone marrow and elutriation fractions FR25 and FR35 for gene expression by reverse transcriptase polymerase chain reaction. Using a semiquantitative protocol, we detected mRNA for beta-globin and flk-2, a protein tyrosine kinase receptor, in all samples except the FR25 Lin- c-kitBR subset. We consider the cells in FR25 Lin- c-kitBR to be the most primitive set of hematopoietic stem cells.

Animals↗
PubMed1994

Pediatric patient education for the operating room staff: the "Barney phenomenon".

The single most important determinant of a child's ability to learn is the child's readiness to accept the information and incorporate it into his frame of reference. To be an effective educator of children, the nurse must understand the following: (1) the child's developmental stage, (2) the tasks and fears associated with that stage, and (3) the ability of the child to understand the concepts being taught. Before teaching can begin, fears and anxieties must be overcome. Each developmental stage, from birth through adolescence is examined from the perspective of the perioperative nurse conducting a teaching program for children and their parents. Guidelines and suggestions for age-appropriate activities to reduce anxiety and teaching methods are emphasized.

Adolescent↗
PubMed1994

Bone marrow and peripheral blood lymphocyte phenotype in patients with bone marrow failure.

Patients with aplastic anemia (AA) respond to immunosuppressive therapy, and several lines of laboratory evidence support a role for cell-mediated immunity in the pathogenesis of marrow failure including expansion of cytotoxic T lymphocytes (CTL) in the blood of AA patients, overexpression of inhibitors such as IFN-gamma in the marrow of AA patients, and suppression of hematopoietic cells by CTL in vitro. However, the phenotype of immune effectors in the marrow of AA patients remains unknown. We examined severe (sAA) and moderate AA (mAA) patients and compared them to healthy volunteers and patients with myelodysplastic syndrome (MDS). Our study shows that percentages of HLA-DR+ CD8+ lymphocytes and natural killer (NK) cells, CD56+, were elevated in the marrow of AA patients. Peripheral blood (PB), in all instances, did not reflect changes seen in the bone marrow (BM). Increased percentages of activated CD8+ cells were found in marrow and blood in 43% of AA patients, but in 28% of AA patients, activation of CD8+ cells was only detectable in the marrow. During hematopoietic recovery, activated CD8+ cells and NK cells in marrow declined, but not to normal levels. T cells bearing the gamma delta-phenotype were elevated in the blood of sAA patients (p < 0.05) but were not significantly increased in BM from sAA and MDS patients. Percentages of activated immune effectors are increased in the marrow of AA patients as is consistent with a localized immune response in this disease. Marrow phenotyping may be more sensitive than peripheral blood analysis for detecting an abnormal cellular immune response.

Anemia, Aplastic↗
PubMed1994

Community responses to AIDS.

Some examples of care in the community for people with HIV/AIDS are reported from Africa. Members of communities committed to fighting the AIDS epidemic cannot do so alone and should be given every possible help. Inadequate care favours the spread of HIV, as does the stigmatization of people with HIV infection and their families.

Acquired Immunodeficiency Syndrome↗