On the mechanism of a 60-Hz electric field induced growth reduction of mammalian cellsin vitro

Data on 60-Hz electric field (EF) induced reduction in growth rate of plant roots have strongly supported the hypothesis that the effect is related to an EF-induced transmembrane potential (V ⁱ _m). An investigation was undertaken to determine if this hypothesis is also applicable to 60-Hz EF-induced reductions in growth rate of mammalian cells in vitro. Human lymphoblastic (RPMI 1788) and human carcinoma (HeLa) cells were selected for study, the former having a relatively small diameter (11.2 m), and the latter having a relatively large diameter (15.4 tm). The 60-Hz EFs ranged from 430–1200 V/m in the culture medium. The growth rate of RPMI 1788 cells after 4-days was depressed by about 42% at a 60-Hz EF of 1000–1200 V/m with a response threshold occurring at 950 V/m; theV ⁱ _m at the response threshold was 8 mV There was no 60-Hz EF-induced effect on HeLa cell growth rate of aV ⁱ _m of 8 mV (60-Hz EF=700 V/m); a statistically significant effect was achieved atV ⁱ _m of 11 mV (950 V/m). The data support the hypothesis that above a threshold 60-Hz EF,V ⁱ _m acts as the initial signal leading to growth rate reductions.     

An instrument for assessment of videotapes of general practitioners' performance.

OBJECTIVES--To identify those important characteristics of doctors'' and patients'' behaviour that distinguish between "good" and "bad" consultations when viewed on videotape; to use these characteristics to develop a reliable instrument for assessing general practitioners'' performance in their own consultations. DESIGN--Questionnaires completed by patients, general practitioner trainers, and general practitioner trainees. Reliability of draft instrument tested by general practitioner trainers. SETTING--All vocational training schemes for general practice in the Northern region of England. SUBJECTS--First stage: 76 patients in seven groups, 108 general practice trainers in 12 groups, and 122 general practice trainees in 10 groups. Second stage: 85 general practice trainers in 12 groups. MAIN OUTCOME MEASURES--Trainers'' ratings of importance; alpha coefficients of draft instrument by trainee, group, and consultation. RESULTS--6890 characteristics of good and bad consultations were consolidated into a draft assessment instrument consisting of 46 pairs of definitions separated by six point bipolar scales. Nine statement pairs given low importance ratings by trainers were eliminated, reducing the instrument to 37 statement pairs. To test reliability, general practitioner trainers used the instrument to assess three consultations. With the exception of one group of trainers, all alpha coefficients exceeded the acceptable level of 0.80. CONCLUSION--The instrument produced is reliable for assessing general practitioners'' performance in their own consultations.     

An optimized live bacterial delivery vehicle safely and efficaciously delivers bacterially transcribed therapeutic nucleic acids

There is an unmet need for delivery platforms that realize the full potential of next-generation nucleic acid therapeutics. The in vivo usefulness of current delivery systems is limited by numerous weaknesses, including poor targeting specificity, inefficient access to target cell cytoplasm, immune activation, off-target effects, small therapeutic windows, limited genetic encoding and cargo capacity, and manufacturing challenges. Here we characterize the safety and efficacy of a delivery platform comprising engineered live, tissue-targeting, non-pathogenic bacteria (Escherichia coli SVC1) for intracellular cargo delivery. SVC1 bacteria are engineered to specifically bind to epithelial cells via a surface-expressed targeting ligand, to allow escape of their cargo from the phagosome, and to have minimal immunogenicity. We describe SVC1's ability to deliver short hairpin RNA (shRNA), localized SVC1 administration to various tissues, and its minimal immunogenicity. To validate the therapeutic potential of SVC1, we used it to deliver influenza-targeting antiviral shRNAs to respiratory tissues in vivo. These data are the first to establish the safety and efficacy of this bacteria-based delivery platform for use in multiple tissue types and as an antiviral in the mammalian respiratory tract. We expect that this optimized delivery platform will enable a variety of advanced therapeutic approaches.     

Alkaline Phosphatase Content and the Effects of Prednisolone on Mammalian Cells in Culture

The alkaline phosphatase content of different tissue culture cell lines has been shown to vary from no detectable activity to high enzyme concentration. Within the epithelial lines studied alkaline phosphatase is either constitutive or inducible. Two epithelial cell strains in which alkaline phosphatase was "absent" could be induced to develop significant amounts of the enzyme when grown in the presence of Δ¹-hydrocortisone. Phosphate did not repress enzyme induction by prednisolone. Under conditions of deadaptation the induced enzyme was diluted by cell multiplication. The mouse fibroblastic L line and several human fibroblastic lines did not contain alkaline phosphatase when grown under the conditions described nor could they be induced to produce the enzyme when cultivated in medium with prednisolone. Δ¹-Hydrocortisone has other characteristic effects on established mammalian cell cultures which vary among cell lines. Human epithelial lines show reduction in cell multiplication with increase in mitotic index. The cytoplasm is increased and cell volume is nearly doubled. Mouse fibroblasts show a similar reduction in cell multiplication with a decrease in mitotic index. There is no increase in cell cytoplasm. Human fibroblast strains show no inhibition of multiplication or alteration in total cell protein when grown in medium containing prednisolone. Antisera prepared against "negative" prednisolone-inducible human cell lines and against a positive human line inhibited alkaline phosphatase activity to an equal degree.     

USE OF SENSORY EVALUATION FOR MEASURING DEODORIZING EFFECTS OF AN AIR CONDITIONER

The application of sensory methodology for measuring deodorizing effect of an air conditioner equipped with electric plasma was introduced. Deodorizing effect was measured using chemical and sensory methods at different time (0, 30 and 60 min) and mode (control, blowing and cooling) of an air conditioner. Smoke from a roll of cigarette in a closed room was used as a source of odor and the concentrations of acetic acid and ammonia were measured as odorous chemical components. As one of the sensory methods triangle test was used and as a first step to obtain deodorizing effects by triangle test, the threshold of each panelist was obtained as the log dilution ratio of odor concentration at which the difference from odorless air was detected. The odor concentration at each time and mode was calculated using the threshold of the panel and the deodorizing effect was obtained on the basis of the odor concentration. In addition to a triangle test, scaling methods such as category scaling or magnitude estimation were used to measure deodorizing effect of an air conditioner. Deodorizing effects by scaling methods were calculated based on odor intensity with time at each mode. The regression analysis was done between the efficacy of deodorizing effect by sensory test and those by acetic acid and ammonia, the R² values of the regression equations for triangle test, category scale, and magnitude estimation were 0.84, 0.72 and 0.69, respectively. Deodorizing effect by triangle test explained the decrease of acetic acid and ammonia better than those by category scaling or magnitude estimation while high cost and time consuming labor involved in triangle tests reduced the merit. The results of this study demonstrated that various sensory methods could be used to measure deodorizing effect of air conditioners and further researches on fast and reliable methods are needed to establish the official procedures.     

Use of nuclear morphometry characteristics to distinguish between normal and abnormal cervical glandular histologies.

This is a methodological study exploring the use of quantitative histopathology applied to the cervix to discriminate between normal and cancerous (consisting of adenocarcinoma and adenocarcinoma in situ) tissue samples. The goal is classifying tissue samples, which are populations of cells, from measurements on the cells. Our method uses one particular feature, the IODs-Index, to create a tissue level feature. The specific goal of this study is to find a threshold for the IODs-Index that is used to create the tissue level feature. The main statistical tool is Receiver Operating Characteristic (ROC) curve analysis. When applied to the data, our method achieved promising results with good estimated sensitivity and specificity for our data set. The optimal threshold for the IODs-Index was found to be 2.12.     

Dose-dependent effect of heparin on fertilizing ability of goat spermatozoa

Intact bovine oocytes were used to study the effect of heparin on goat IVF. Oocytes were matured in Medium 199 plus estrous sheep serum. Fresh semen was incubated for 4 h at room temperature, and spermatozoa were then resuspended in medium Talp plus serum and incubated further for 1 h at 39 degrees C in 5% CO(2) in air. Later, spermatozoa were resuspended in Talp plus serum and heparin and were then incubated in microdrops until the oocytes were matured. In Experiment 1, the effect of heparin on spermatozoa from individual males was studied by a dose-response curve. In Experiment 2, the timing of sperm penetration in matured oocytes was studied to assess the stage at which the action of heparin could be expressed in the fertilization process. In Experiment 3, heparin from the same source but at different grades of bioactivity was adjusted for bioactivity and its effect on spermatozoa was compared in terms of penetration rates in order to identify heparin-dependent variations on goat IVF. In Experiment 4, the influence of calcium on the effect of heparin at different levels of bioactivity on the fertilizing ability spermatozoa was assessed as in Experiment 3. In Experiment 5, different batches of heparin from the same source and grade of bioactivity were compared as above. The results suggest that 1) heparin stimulates fertilization rates following a comparable pattern between males; 2) the most probable site of action is at the stage of sperm capacitation; and 3) provided that the source and grade of bioactivity is preserved, heparin maintains the efficiency of sperm penetration into matured oocytes.