Biomedical subjects
Publications and source records attributed to L Green.
We have developed a rapid assay of antifungal activity which utilizes flow cytometry to detect accumulation of a vital dye in drug-damaged fungal cells. Results of these studies suggest that flow cytometry may provide an improved, rapid method for determining and comparing the antifungal activities of compounds with differing modes of action.
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Homeless people need emotional support, caring professionals, and resources that work within their frame of reality. Each homeless community will have different demographics and health needs. The common denominators are the obstacles encountered when trying to access health care: bureaucracy, transportation, accessibility, present-time orientation, limited resources, frustration, and anxiety. Nurse-managed free clinics are an effective means of serving the needs of homeless and indigent populations. Through these clinics, clients can receive continuity of care, proper follow-up, referrals, and teaching to aid in the prevention of illness. A free clinic was established in a northwestern Georgia community to meet the health needs of homeless and indigent persons. This article describes the demographics, attitudes, values, perceived support systems, and health needs of clients accessing care at this nursing clinic.
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Several morphologic studies have suggested that gap junctions exist between bone marrow stromal cells. This possibility was examined by analysis of stromal cells present in the adherent layer of primary long-term lymphoid bone marrow cultures and in additional studies using a stromal cell line. Results showing that the fluorescent dye lucifer yellow, when microinjected into a single stromal cell, transferred between most other contacting stroma and that stromal cells were electronically coupled provided support that cell-cell communication occurs between these microenvironmental elements. Additional studies showed that transcripts for connexin (Cx) 43, but not for Cx26 or Cx32, were present in a stromal cell line. To examine the potential for regulated cell-cell communication between the stroma, cells were treated with interleukin-1 (IL-1), a cytokine known to affect stromal cell function, and the effects on dye transfer were examined. IL-1 treatment resulted in a reversible decrease in the ability of dye to transfer between stromal cells in contact. Taken together, these studies show that gap junctions exist between stromal cells and that their permeability can be regulated. However, gap junction-mediated cell-cell communication could not be shown between the stroma and developing lymphoid cells.
Exposure patterns are reported for manufacturing and sprayer cohorts incorporated in the "IARC International Register of Workers exposed to Phenoxy Herbicides and Contaminants." Information was based on company questionnaires, company reports, plant visits, and serum 2, 3, 7, 8-TCDD measurements. In addition to phenoxy herbicides and chlorophenols, workers in manufacturing plants may have been exposed to raw materials, process chemicals, other agents synthesized or formulated, and impurities of all these agents. Sprayers also had a complex exposure pattern, including phenoxy herbicides and some other pesticides, their carriers and additives, and residues of chemicals formed during manufacture. Occurrence of agents, including dioxins, varied between countries. Biological monitoring and industrial hygiene data were rarely available, most since the late 1970s. Exposure of workers depended mainly on the jobs they performed, but several factors influenced level of exposure. A quantitative exposure classification is not feasible in this study. Semiquantitative exposure estimates may be derived through a critical interpretation of biological monitoring and industrial hygiene data together with individual work histories.
The relation between molar and molecular aspects of time allocation was studied in pigeons on concurrent variable-time variable-time schedules of reinforcement. Fifteen-minute reinforcer-free periods were inserted in the middle of every third session. Generalized molar matching of time ratios to reinforcer ratios was observed during concurrent reinforcement. Contrary to melioration theory, preference was unchanged during the reinforcer-free periods as well as in extinction. In addition to this long-term effect of reinforcement, short-term effects were observed: Reinforcers increased the duration of the stays during which they were delivered but had little consistent effect either on the immediately following stay in the same schedule or on the immediately following stay in the alternative schedule. Thus, an orderly effect of reinforcer delivery on molecular aspects of time allocation was observed, but because of its short-term nature, this effect cannot account for the matching observed at the molar level.
OBJECTIVE: To elucidate the role of anticardiolipin antibodies (aCL) in the pathogenesis of hemolytic anemia in patients with systemic lupus erythematosus (SLE). METHODS: Immunoglobulins (Ig) and cardiolipin reactivity were evaluated in red blood cell (RBC) eluates and in the sera of patients with SLE and controls by a solid phase enzyme linked immunosorbent assay. RESULTS: aCL were detected in sera of 2 patients with SLE with active hemolytic anemia. The RBC eluates of these patients contained Ig (mainly IgG) with significant cardiolipin reactivity. RBC eluates from healthy volunteers failed to demonstrate measurable amounts of Ig whereas Ig eluted from RBC of chronic lymphocytic leukemia patients with active hemolysis but no aCL did not react with cardiolipin. Furthermore, under treatment, one patient went into complete remission with resolution of the hemolysis, negative Coombs' tests and lower serum aCL. The other patient, however, continued to demonstrate both high sera aCL and positive Coombs' tests. CONCLUSION: aCL may play a direct role in the pathogenesis of hemolytic anemia in some patients with SLE by acting as anti-RBC autoantibodies.
Current concepts in gene transfer and its application to the treatment of human genetic disorders, cancer, and other diseases are discussed. Gene therapy is a technique in which a functioning gene is inserted into a human cell to correct a genetic error or to introduce a new function to the cell. Many methods, including retroviral vectors, have been developed for ex vivo and in vivo gene insertion into cells. Some pharmacists have likened gene therapy to a sophisticated form of drug delivery and have envisioned an active role for the pharmacy profession. There are several safety and ethical issues related to manipulating the human genome that need to be understood. Current gene therapy efforts focus on gene insertion into somatic (nongerminal) cells only. Gene therapy has the potential to revolutionize the treatment of genetic disorders, diseases associated with a genetic component (e.g., cystic fibrosis), cancer, AIDS, and many other diseases. Gene transfer may also be used to better understand the biology of disease processes, such as the source of relapse in bone marrow transplant patients. The human genome project will undoubtedly lead to the identification, characterization, and understanding of genes that are responsible for many human diseases, and gene therapy trials are sure to expand accordingly. To date, over 40 clinical trials have been approved and more than 110 patients have been entered in gene therapy studies. There are still many technical obstacles to overcome before gene therapy can have widespread application. Injectable vectors need to be developed to simplify foreign gene administration. Perhaps the biggest problem to overcome will be engineering the target cells to be able to regulate gene expression according to physiologic needs. Pharmacists should become knowledgeable about gene transfer techniques and possible clinical applications of gene therapy to keep abreast of the newest trends in medicine.
Lyme disease is an expanding community health issue in the United States. This has led to greater public awareness in Canada, although the disease remains rare here. We review the biology of ticks and show how feeding patterns are relevant to disease transmission. Diagnosing Lyme disease is sometimes problematic, but treatment can be effective, particularly in the early stages. Preventive measures are aimed at avoiding tick contact and early tick removal.
BACKGROUND: DNA aneuploidy has been prognostically significant in female breast carcinoma of low stage, but its value in male breast carcinoma remains undetermined. METHODS: Flow cytometric DNA analyses were performed retrospectively on paraffin-embedded tissue from 32 men with breast carcinoma (mean follow-up time, 5.97 years [standard deviation +/- 4.63]; range, 1 to 18 years). RESULTS: Multivariate discriminant function analysis showed only tumor size less than 2 cm to be independently predictive of better disease-free survival (P less than 0.05). DNA ploidy (aneuploid, 25 patients; diploid, 7 patients) and lymph node status (positive, 22 patients; negative, 10 patients) were not predictive of survival, regardless of tumor size. CONCLUSIONS: The authors concluded that DNA ploidy may not significantly predict survival in male breast carcinoma.
This study investigated whether attributions of opiate addicts would predict both their ability to abstain from future use and their reactions to abstinence violations. Measures of generalized beliefs about responsibility for positive and negative outcomes and specific attributions about relapse episodes were elicited from 80 addicts at the time of admission for inpatient detoxification and treatment. Addicts who at admission attributed to themselves greater responsibility for negative outcomes and who attributed relapse episodes to more personally controllable factors were subsequently (at 6-month follow-up) more likely either to be completely abstinent or to contain the effects of temporary lapses into opiate use.
The translational roles of the Shine-Dalgarno sequence, the initiation codon, the space between them, and the second codon have been studied. The Shine-Dalgarno sequence UAAGGAGG initiated translation roughly four times more efficiently than did the shorter AAGGA sequence. Each Shine-Dalgarno sequence required a minimum distance to the initiation codon in order to drive translation; spacing, however, could be rather long. Initiation at AUG was more efficient than at GUG or UUG at each spacing examined; initiation at GUG was only slightly better than UUG. Translation was also affected by residues 3' to the initiation codon. The second codon can influence the rate of initiation, with the magnitude depending on the initiation codon. The data are consistent with a simple kinetic model in which a variety of rate constants contribute to the process of translation initiation.
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Binary complexes between messenger RNA and E. coli ribosomes were examined. A ribosome-mRNA binary complex on T4 gene 32 mRNA withstood inhibition by antibodies against ribosomal protein S1. Anti-S1 blocks ternary complex formation, as measured by "extension inhibition" or "toeprinting" analysis, only when preincubated with ribosomes prior to mRNA addition and not when anti-S1 was added after preincubation of ribosomes and mRNA. The ribosome was directly localized in a binary complex on two translation initiation sites by toeprinting analysis. In the absence of tRNA the ribosome halted cDNA synthesis by reverse transcriptase close to the Shine and Dalgarno sequence. Binary complex formation was inhibited by an oligodeoxynucleotide competitor of the Shine and Dalgarno sequence.
STUDY OBJECTIVE: To evaluate the clinical assessment of splenic enlargement using specific bedside maneuvers including Traube's space percussion, the splenic percussion sign, Middleton's maneuver, supine palpation, and right lateral decubitus palpation. DESIGN: Quasi-experimental prospective study of cases and controls selected according to the results of abdominal ultrasonographic examinations. SETTING: Selected inpatients of a tertiary care hospital. MAIN RESULTS: Comparing the areas under the receiver operating characteristic curves for each bedside maneuver demonstrated that Traube's space percussion and palpation were significant discriminators (p less than 0.001) of splenic enlargement with respective areas of 0.70 +/- 0.04 and 0.76 +/- 0.04. No one palpation maneuver was superior to another, and right lateral decubitus palpation was not useful when performed after supine palpation. The splenic percussion sign (sensitivity 79%, specificity 46%) was no better than Traube's space percussion (sensitivity 62% and specificity 72%) in assessing splenic enlargement. The palpation maneuvers appeared more sensitive and more specific than Traube's space percussion. Palpation was a significant clinical discriminator when performed on patients who exhibited percussion dullness of Traube's space (area = 0.87 +/- 0.04, p less than 0.0001) but was of little value among those without percussion dullness (area = 0.55 +/- 0.08). Also, palpation was significantly more accurate when performed on lean patients versus obese patients (areas = 0.83 +/- 0.04 versus 0.65 +/- 0.08, p less than 0.05). When a positive bedside examination was defined as positive palpation and positive percussion (concordant-positive), the combined test sensitivity and specificity were 46% and 97% respectively. CONCLUSIONS: The optimal clinical assessment of splenic enlargement includes the percussion of Traube's space. If Traube's space is dull, palpation of the spleen is warranted. This assessment is most accurate in lean patients.