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Biomedical subjects

J Davis

Publications and source records attributed to J Davis.

At least 379 records · Page 21Linked to original sources
PubMed1987

Social problems encountered by public health nurses: identification and response differences according to education and experience.

Do nurses differ in relation to the identification of social problems and actions taken according to educational preparation? Using data from a larger field study, baccalaureate nurses (BSNs) were compared to Non-BSNs. The two groups did not differ in the number of problems that were identified, but BSNs did identify more problems related to non-immediate needs. The nurses took up to ten actions (means = 4.6) per problem, and the average number per BSN was less than the average per Non-BSN. The data lend some support to the position that BSNs are more likely to be self-assured and self-directed. Several questions are raised that are relevant to educators and administrators.

Aged↗
PubMed1987

X-linked lymphoproliferative syndrome provides clues to the pathogenesis of Epstein-Barr virus-induced lymphomagenesis.

X-linked lymphoproliferative disease (XLP) is a rare genetic syndrome that continues to serve as a useful model to understand more broadly the role of immunodeficiency and the pathogenetic mechanisms for the spectrum of Epstein-Barr virus (EBV)-induced diseases to which XLP is predisposed. Apart from XLP, EBV infection is related to the high frequency of non-Hodgkin's lymphoma in children with various primary immune deficiency diseases and in allograft recipients. More recently, EBV has been implicated in several lymphoproliferative diseases in individuals with acquired immune deficiency syndrome. Studies thus far on patients with XLP suggest that immune deficiency is a major determinant of these diseases. Additional molecular aberrations must be necessary in the pathogenesis of lymphoma to convert polyclonal to monoclonal disease.

Female↗
PubMed1987

Diagnosis of murine mycoplasmal infections by enzyme-linked immunosorbent assay (ELISA).

ELISA is the currently accepted method for screening rodent colonies for Mycoplasma pulmonis infection. While this assay has greatly improved mycoplasmal detection, it suffers from major defects. Cross-reactions with M. arthritidis are the major technical problem, and prevent definitive diagnosis. Current methods for obtaining a definitive diagnosis are accurate in about 80% of cases, and include ELISA testing for both organisms, immunoblot analysis, and blocking of the murine reaction with heterologous serum. Another technical difficulty is the inherent variability in the assay, which can be overcome by rigid quality control measures and careful attention to detail. The difficulties that arise from the natural history of mycoplasmal infection in barrier-maintained colonies, i.e., low incidence of infected animals and delayed antibody response in animals infected with low numbers of organisms, seriously limit the usefulness of the ELISA. While the assay can be extremely useful in screening breeding colonies and in eliminating mycoplasmas from such colonies, it cannot easily be used to screen potential sources of weanling animals for experimental use.

Animals↗
PubMed1987

CFU-GM content of bone marrow graft correlates with time to hematologic reconstitution following autologous bone marrow transplantation with 4-hydroperoxycyclophosphamide-purged bone marrow.

Autologous bone marrow transplants (BMTs) can repopulate the hematologic system of patients treated with marrow-ablative chemotherapy and/or radiotherapy. However, treatment of the bone marrow graft to eliminate residual tumor cells prior to reinfusion can delay the return of peripheral blood elements, presumably from damage to or loss of hematopoietic stem cells responsible for hematologic recovery. To develop a model predictive of hematologic recovery, we studied the progenitor cell contents of 4-hydroperoxycyclophosphamide (100 micrograms/mL)-purged bone marrow grafts of 40 consecutive patients undergoing autologous BMT at this center. Granulocyte-macrophage colonies (CFU-GM) were grown from all grafts after treatment with this chemotherapeutic agent, but erythroid (BFU-E) and mixed (CFU-GEMM) colonies were grown from only 44% and 33% of the grafts respectively. The recovery of CFU-GM after purging ranged from 0.07% to 23%. The logarithm of CFU-GM content of the treated grafts was linearly correlated with the time to recovery of peripheral blood leukocytes (r = -0.80), neutrophils (r = -0.79), reticulocytes (r = -0.60), and platelets (r = -0.66). The CFU-GM content of purged autologous bone marrow grafts may reflect the hematopoietic stem cell content of the grafts and thus predict the rate of hematologic recovery in patients undergoing autologous BMT.

Adolescent↗
PubMed1986

Protein secretion from Saccharomyces cerevisiae directed by the prepro-alpha-factor leader region.

The Saccharomyces cerevisiae secretory process was studied by evaluating secretion efficiency, processing efficiency, and the efficiency of protein folding for hybrid proteins containing the yeast prepro-alpha-factor leader region. Secretion of three proteins, beta-endorphin, calcitonin, and a consensus alpha-interferon (IFN-Con1), were compared in terms of secretion efficiency into the culture medium, beta-Endorphin and calcitonin, both small proteins, were found to be efficiently secreted from logarithmically grown cells. In contrast, the larger IFN-Con1 accumulated in the periplasmic space and cell wall. The glycosylated, unprocessed prepro-alpha-factor/IFN-Con1 fusion protein was also found to be secreted into the culture medium. The presence of (Glu-Ala) dipeptides in the alpha-factor spacer peptide increased the efficiency of cleavage at Lys-Arg in the prepro-alpha-factor/IFN-Con1 protein fusion. Purified secreted IFN-Con1 was structurally characterized to determine the effect of passage through the yeast secretory pathway on the fidelity and efficiency of protein folding. The disulfide structure of the secreted protein was found to be identical with that reported for the native human alpha-interferons.

Amino Acid Sequence↗
PubMed1986

Experience with a totally implantable venous device in children.

Venous access was attained in 15 children by use of a totally implantable central venous catheter and reservoir. Catheters were in place from 28 to 581 days, giving a cumulative experience of 4,094 days. Although they were well accepted by physicians, parents, and the children, they were not without major complications. These included extravasation of a chemotherapeutic agent in one, migration of the catheter tip to an unacceptable location in another, and catheter thrombosis and catheter-related sepsis in two each. The malpositioned catheter, one of the thrombosed catheters, and both infected catheters were removed. Ease of care, freedom from protruding tubing, and compatibility with normal activities are major positive features of the implantable devices that should be considered when deciding on the type of prolonged central venous access for use in children being treated with cancer.

Adolescent↗
PubMed1986

Cytologic regression grading of hormone-treated prostatic cancer.

Aspiration cytology during hormone treatment of prostatic cancer has been regularly performed at the University of Munich for 13 years and gives direct information on the primary tumor. To analyse its value in clinical practice, 919 biopsies of 187 patients were reviewed without knowledge of clinical data and the charts were analysed retrospectively. Each biopsy was classified as having good, medium, or poor therapeutic response depending on the regressive changes of the cells. Agreement between two independent observers was 89%. All but 39 of these patients have died and the surviving patients have a minimum observation period of 5.6 years. A poor therapeutic response was seen cytologically in 72 patients (38.5%) at variable times after treatment began. These patients have a statistically significant worse survival in comparison to all other patients. Forty-seven of these 72 patients had deterioration, but clinical signs developed later in 23 cases (mean 1.1 years); in 21 patients cytology and clinical signs were simultaneous and in only three cases clinical deterioration preceded aspiration cytology (mean 4.8 months). In 25 cases there was a cytologically poor therapeutic response, but no clinical signs of deterioration. These patients had the same survival rate as with good or medium treatment response. Serial aspiration cytology is a very valuable parameter in treatment monitoring and is often the early warning sign of endocrine treatment failure.

Aged↗
PubMed1986

In-vitro infection of chronic lymphocytic leukemia cells by Epstein-Barr virus (EBV).

We sought to determine the potential of infecting lymphoid cells from patients with chronic leukemia (CLL) with Epstein-Barr virus (EBV) by testing for EBV receptors (EBVR) by flow cytometry, assessing for infectability of these cells by culturing with B95-8-derived virus, and staining for EB nuclear-associated antigens (EBNA) at various times post-infection. EBVR were present on 54-91% of lymphoid cells in seven cases of CLL and on 46% of prolymphocytic leukemia cells. Dynamic changes regarding EBNA positivity, morphology, and viability occurred post-infection with the virus. On day 2 only a few EBNA-positive lymphoblasts were observed. On days 11-21 positivity increased from 2 to 34% of cells. Simultaneously, the viable cell number declined to approximately 1/10th of original number. A significant proportion of the EBNA-positive cells corresponded to the original CLL cells. In 3 of 7 cases of CLL a Pan T-cell phenotype was demonstrated by Leu-1 monoclonal antibody testing. The infected cells did not react with two monoclonal antibodies, EBV-CS 1 and 4, which react with B-cell lymphoblastoid cell lines (B-LCL). Moreover, the B-LCL derived at 1-2 months post-infection of CLL cells did not express the Leu-1 antigen, but expressed EBV-CS 1 or 4 defined antigens. In the prolymphocytic leukemia, 64% of the cells showed EBNA positivity on day 7 and giant cells with huge round or multiple nuclei appeared which were EBNA-positive. CLL and prolymphocytic leukemia cells can be infected as demonstrated by EBNA-positivity. This infection does not lead to immediate transformation, but evokes lymphoblast and multinucleated giant cell production prior to the death of cells.

Aged↗
PubMed1986

Impact of aminoglycoside serum assays on clinical decisions and renal toxicity.

To determine whether serum aminoglycoside assays aided clinicians in treating infections and avoiding aminoglycoside nephrotoxicity, we reviewed the charts of patients treated with aminoglycoside antibiotics parenterally. We compared 78 episodes of aminoglycoside-treated infections during which serum assays were done (group B) to 51 episodes without serum assays (group A). The groups of patients were comparable in age, outcome of infection, incidence of aminoglycoside nephrotoxicity, mean total dose of aminoglycosides given, and number of courses. Toxic trough levels of tobramycin (the most frequently used aminoglycoside) were seldom detected before the onset of nephrotoxicity, and peak tobramycin levels were frequently suboptimal. While 71% of decisions to increase or decrease the aminoglycoside dose after serum assays were considered appropriate, only 57% of noninterventions were appropriate. At our hospital, serum aminoglycoside assays did not help improve the outcome of infection or the incidence of nephrotoxicity. Their major clinical contribution was to alert the physician that serum concentrations were low.

Amikacin↗