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Biomedical subjects

R Armon

Publications and source records attributed to R Armon.

10 recordsLinked to original sources
PubMed1996

In vitro inhibition of Helicobacter pylori by extracts of thyme.

Extracts of several plants were tested for inhibitory activity against Helicobacter pylori. Among these plants thyme (aqueous extract) and cinnamon (alcoholic extract) were the most effective. Since aqueous extract of thyme is easier to produce and consume, it was further investigated. Compared with several antibacterials, the thyme extract had a significant inhibitory effect on H. pylori, reducing both its growth and potent urease activity. From the results of this study, the aqueous extract of thyme possesses a therapeutic potential which merits validation by clinical studies.

Anti-Bacterial Agents↗
PubMed1993

A simple, rapid and sensitive presence/absence detection test for bacteriophage in drinking water.

A rapid, simple and sensitive direct bacteriophage presence detection method for 500 ml drinking water samples has been developed. The method includes a glass device consisting of a jar containing the water sample and an immersible probe filled with solidified soft agar containing bacterial host cells. Host bacteria in logarithmic phase were added to the experimental volume and the probe was submerged. The entire device was incubated in a water bath at 36 degrees C. Plaques of somatic bacteriophage infecting Escherichia coli strain CN13, could be detected within 3 h. Male-specific bacteriophages infecting E. coli F+ amp were detected within 6 h. Bacteriophage infecting the anaerobe Bacteroides fragilis subsp. fragilis HSP40 were detected after 8 h. Application of this device and the associated technique, enabled a one-step detection of 1 pfu of E. coli or Bact. fragilis specific bacteriophage in 500 ml drinking water samples.

Agar↗
PubMed1990

Biochemical fingerprints of Legionella spp. by the BIOLOG system: presumptive identification of clinical and environmental isolates.

Six Legionella strains were characterized with the BIOLOG identification system. A specific metabolic pattern for the six Legionella strains was observed after 24 h. Several positive reactions were detected intermittently in all six strains tested. The possible application of the BIOLOG system for identification of Legionella spp. from environmental or clinical samples is discussed.

Bacterial Typing Techniques↗
PubMed1989

Pig erythrocyte ghost cells used for concentration of enteric viruses from experimentally contaminated clinical specimens.

A simple, rapid and efficient procedure of virus concentration from urine, cerebrospinal fluid (CSF), and feces was developed. Pig erythrocyte ghost cells were used to adsorb and elute such viruses as poliovirus LSC-1, echovirus 6, and human rotavirus (clinical isolate). In urine and CSF, the adsorption efficiency range was 80-100% and elution was from 85% to greater than 100%. In addition, poliovirus LSC-1 was used as an experimental model to examine this procedure under various clinical conditions, such as calcium, glucose, amino acids, and urea at high concentrations. These were added to normal urine specimens to simulate pathological conditions. The results suggest that pig erythrocyte ghost cells are an efficient matrix for adsorption and elution of enteric viruses found in clinical specimens of urine, CSF, and feces. This method might be useful in virus concentration from clinical specimens and for preparative microscopy and other clinical laboratory methods that require subsequent virus concentration.

Animals↗
PubMed1989

Concentration of Giardia lamblia cysts, Legionella pneumophila, Clostridium perfringens, human enteric viruses, and coliphages from large volumes of drinking water, using a single filtration.

Poliovirus, coliphages, Giardia lamblia cysts, Clostridium perfringens spores, and Legionella pneumophila were concentrated simultaneously in a single pass by sequential filtration of large volumes of drinking water through 3- and 1-micron wound electronegative fiberglass cartridge filters (25.4 cm). Filtration was performed under acidic conditions (pH 3.5) in the presence of 0.001 M aluminum chloride to enhance adsorption. Elution of all the microorganisms entrapped or adsorbed to the filters was obtained by a slow backwash elution with a 1.5% beef extract solution, pH 9.75, containing 0.5% Tween 80. Tween 80 was shown to enhance recovery of the bacteriophages, bacteria, and parasites. Giardia cysts were efficiently eluted (71%) and could be reconcentrated by low-speed centrifugation and purified by sucrose density gradient flotation at a final recovery of 52%. Legionella pneumophila cells were eluted at 64% and were further concentrated by low-speed centrifugation at an overall recovery of 55%. C. perfringens spores and coliphages were eluted at efficiencies of 82 and 86%, respectively, and reconcentrated with minimal loss by a detergent - protein flotation method. Poliovirus was eluted at 93% and reconcentrated at 78% efficiency by organic flocculation.

Animals↗
PubMed1988

A modified m-CP medium for enumerating Clostridium perfringens from water samples.

Medium m-CP, designed for the isolation of Clostridium perfringens from water samples, contains indoxyl beta-D-glucoside, an expensive chemical that is present at a high concentration in this medium. The use of m-CP with three concentrations of indoxyl beta-D-glucoside was tested at 0, 60, and 600 mg/L. Lowering the amount of indoxyl beta-D-glucoside to 60 mg/L (1/10 the recommended concentration) reduced the cost of this medium without affecting its sensitivity.

Clostridium perfringens↗
PubMed1988

A highly efficient second-step concentration technique for bacteriophages and enteric viruses using ammonium sulfate and Tween 80.

Addition of Tween 80 to a 1.5% solution of beef extract was found to enhance the elution of bacteriophages adsorbed to electronegative filters. When reconcentration of the eluate was attempted by ammonium sulfate precipitation, a floating layer containing most of the viruses was formed. This floating layer can be obtained with several nonionic detergents including Tween 80 and under a salt saturation of 55% with ammonium sulfate, potassium tartrate, and sodium phosphate. Virus recovery ranged from 91 to 103% and was obtained with several bacteriophage strains. With poliovirus type 1, coxsackievirus B-4, and rotavirus SA-11 the recoveries were 100, 20, and 80%, respectively, but toxicity to cell culture was encountered: after removal of the detergent by a second floating layer method the recovery was 32% for poliovirus. Compared with organic flocculation, this method also had both improved recovery for bacteriophages and protective properties for samples frozen at -70 degrees C.

Adsorption↗
PubMed1984

Ghost cells as sorption matrix for virus concentration from water.

Pig erythrocyte membranes were used as adsorbent material for the concentration of bacteriophage phi x-174, MS-2, and f2 from 5 ml of saline solution. The adsorption was carried out at pH 3.5, and the elution was carried out at pH 7.0. Compared with adsorption on 3% beef extract, bacteriophage adsorption on erythrocyte ghost cells yielded 93 to 100%, and elution was 92 to 100%, whereas beef extract organic flocculation yielded adsorption of 0 to 98.8% and elution of 61 to 86.6%. The same procedure but with poliovirus LSC-1 gave 100% adsorption and 91 to 129% elution.

Adsorption↗
PubMed1983

Concentration of simian rotavirus SA-11 from tap water by membrane filtration and organic flocculation.

Simian rotavirus SA-11 was concentrated from tap water by adsorption to and elution from microporous filters, followed by organic flocculation. Two types of filters were compared for their ability to concentrate the virus. Both Zeta Plus 60S and Cox AA type M-780 filters were efficient for virus adsorption, but the efficiency of virus elution was higher with Zeta Plus than with Cox filters. Optimum conditions for virus recovery from Zeta Plus filters included an input water pH of 6.5 to 7.5 and the use of 3% beef extract (pH 9.0) for elution. Under these conditions, an average of 62 to 100% of the virus was recovered in the concentrate. Organic flocculation was used as a second-step concentration method, with average recoveries of 47 to 69%. When the two methods were used to concentrate small numbers (7 to 75 PFU/liter) of input rotavirus, an average of 75 +/- 40% recovery was achieved. With large volumes of input water, however, recovery was reduced to 16 +/- 7%.

Flocculation↗