Test Vials Research Articles

Laboratory Evaluations of Igr's and Toxicants Against the Larvae of the Oriental Rat Flea, 1986

Abstract A 10-g sample of a mixture of fine sand and flea larval diet was placed in a 25-ml screw-capped vial. An appropriate concentration of technical IGR or toxicant in 500 u.1 of acetone was added to the mix; after stirring, the acetone was evaporated at room temperature. Twenty-four h later, 200 u.1 of water was added and stirred into the mix. Twenty-five laboratory-reared, 2nd-stage larvae were added. Vials were covered with 0.3-mm mesh marquisette cloth and held in separate chambers at 75% RH, 26731° ± 1°C and corresponding 8/16 dark/light cycle. Each test was replicated 2 to 4 times. Control vials containing the sand-diet mix were treated with the acetone only and handled in the same manner as test vials. At 30 days after establishment the vials were examined. Any emerged fleas were killed with a drop of chloroform, and the number of cocoons and emerged fleas were counted. The highest concentration of toxicant tested was 100 ppm; dilutions to 0.0001 ppm were tested, as needed to obtain reduced mortality.

Nonweekend schedule for BACTEC drug susceptibility testing of Mycobacterium tuberculosis.

Determination of the drug susceptibility of Mycobacterium tuberculosis by conventional methods using an agar-based medium may take 3 weeks or more to complete. On the other hand, results on positive cultures are generally available in 4 to 7 days with the radiometric (BACTEC, Johnston Laboratories, Towson, Md.) procedure. One disadvantage to the latter is the requirement to determine the quantity of 14CO2 in each test vial on a daily basis from the day of inoculation. Growth index readings often must be made over weekends, adding to the work load of clinical laboratories during periods of reduced staff or necessitating compensatory pay or time. Susceptibility tests with streptomycin, isoniazid, ethambutol, and rifampin against 104 M. tuberculosis strains were performed by the submerged disk method, the recommended BACTEC method with daily growth index readings, and the radiometric procedure with readings delayed for 2 days after inoculation. Criteria for interpretation of "delayed" tests were established. Drug concentrations tested included some modifications of those available commercially. Overall agreement for the four drugs by the three methods was greater than 90%. We conclude that under our test conditions a schedule of inoculation of radiometric test vials on Friday with growth index readings commencing on Monday gives susceptibility results that correlate well with the daily BACTEC method and with a conventional 7H10 agar method.

Laboratory Evaluation of Igr’s and Toxicants Against the Larvae of the Oriental Rat Flea, 1985

Abstract A 10 g sample of a mixture of fine oven-dried sand and flea larval diet was placed in a 25-ml sere-capped vial. An appropriate concentration of technical IGR or toxicant in 500 μl of acetone was added to the mix; after stirring, the acetone was evaporated at room temperature. Twenty-four h later, 200 μl of water was added and stirred into the mix and 25 laboratory-reared, 2nd-stage larvae were added. Vials were covered with 0.3-mm mesh marquisette cloth and held in separate chambers at 75% RH, 26°/31° ± 1°C and corresponding 8/16 dark/light cycle. Each test was replicated 2 to 4 times. Control vials containing the sand-diet mix were treated with acetone only and handled in the same manner as test vials. At 30 days after establishment, the vials were examined. Any emerged fleas were killed with a drop of chloroform, and the number of cocoons and emerged fleas was counted. The highest concentration of toxicant tested was 100 ppm; dilutions to 0.002 ppm were tested, as needed to obtain reduced mortality.

A NEW APPROACH IN ENHANCED BIODEGRADATION OF SPILLED OIL: DEVELOPMENT OF AN OIL DISPERSANT CONTAINING OLEOPHILIC NUTRIENTS

ABSTRACT A research program has been set up to develop oil dispersants containing oleophilic nutrients. This new type of dispersant will not only dilute the oil slick into the sea, but also start and speed up the microbial growth around the fine oil droplets, because the nutrients remain at the oil/water interface and are not washed away in the water. Each of these newly synthesized nutrients is made of an oleophilic part (normal paraffine or olefine) and of a hydrophilic moiety (containing nitrogen and or phosphorus). This surfactant-like structure allows it to maintain a good level of dispersing efficiency. The capacity to stimulate biodegradation of the various compounds was evaluated by measuring the microbial CO2 production (mineralization) in a gas train arrangement of 40 channels monitored by a 40-way valve. This guaranteed a constant air supply to each test vial. A practical partition coefficient of the nutrient between oil and water was determined to evaluate its ability to remain at the interphase. The influence of the following parameters on the biodegradation process was studied: Amount and chain length of the oleophilic part and type of nutrient, used as such or incorporated in a dispersant Replacement or no replacement of the water phase prior to degradation, to simulate the washing of nutrients into the sea Dispersing efficiency of HLB of the formulated dispersant These results combined with pilot scale trials led to the formulation of a dispersant which exhibits a high dispersion efficiency and a quick-starting biodegradation of the dispersed crude oil.

Laboratory Evaluation of Igr’S and Toxicants Against the Larvae of the Oriental Rat Flea, 1984

Abstract A 10-g sample of a mixture of fine sand flea larval diet was placed in a 25-ml screw-capped vial. An appropriate concentration of technical IGR or toxicant in 500 µl of acetone was added to the mix; after stirring, the acetone was evaporated at room temperature. Twenty-four h later, 200 p.1 of water was added and stirred into the mix. Twenty-five laboratory-reared, 2nd-stage larvae were added. Vials were covered with 0.3-mm mesh marquisette cloth and held in separate chambers at 75% RH, 26°/31°± 1° C and corresponding 8/16 dark/light cycle. Each test was replicated 2 to 4 times. Control vials containing the sand-diet mix were treated with the acetone only and handled in the same manner as test vials. At 30 days after establishment the vials were examined. Any emerged fleas were killed with a drop of chloroform, and the number of cocoons and emerged fleas were counted. The highest concentration of IGR or toxicant tested was 100 ppm; dilutions to 0.01 ppm were tested, as needed to obtain reduced mortality.

Effect of antibiotic treatment on sputum elastase in bronchiectatic outpatients in a stable clinical state.

Broad spectrum antibiotic treatment was given on 21 occasions to 15 patients with bronchiectasis who regularly produced purulent, elastase positive secretions. Although the results showed that sputum clearing--that is, changing from purulent to mucoid--largely depended on the pathogenic organism isolated, this was not exclusively the case and in some cases sputum growing sensitive organisms failed to clear whereas clearing occurred in other samples containing resistant organisms or no obvious pathogens. Clearing of sputum was achieved eventually in 12 of the patients and this was associated with the disappearance of elastase activity, although it returned in 10 patients within one week of stopping treatment. There was no change in sputum elastase where the sputum failed to clear. The clearance of elastase activity was associated with a decrease in protein transudation into the lung secretions. The sputum:serum albumin concentration ratio fell (p less than 0.005) from a mean (SD) of 2.32 (1.56) X 10(-2) in these 12 patients before treatment to 1.09 (0.40) X 10(-2) within the first week of treatment, but rose again to 2.07 (1.29) X 10(-2) within one week of stopping treatment. The results suggest that antibiotic treatment when patients are in a stable state may have a beneficial effect on the pathogenic nature of lung secretions and inflammation within the lung.

Laboratory Evaluation of Igr’s and Toxicants Against the Larvae of the Oriental Rat Flea, 1983

Abstract A 10-g sample of a mixture of fine sand and flea larval diet was placed in a 25-ml screwcapped vial. An appropriate concentration of technical IGR or toxicant in 500(i 1 of acetone was added to the mix; after stirring, the acetone was evaporated at room temperature. Next, 200 jil of water was added and stirred into the mix. Twenty-five laboratory-reared, 2nd-stage larvae were added. Vials were covered with 0.3-mm mesh marquisette cloth and held in separate chambers at 75% RH, 29 ± 1° and 8/16 dark/light cycle. each test was replicated two to four times, control vials containing the sand-diet mix were treated with the acetone only and handled in the same manner as test vials. Vials were examined weekly for 2 or 3 weeks; any cocoons were removed and placed in 3.7-ml shell vials and covered with marquisette cloth. Twenty-one days after removal of the cocoons, any emerged fleas were killed with chloroform and counted. The highest concentration of IGR or toxicant tested was 100 ppm; dilutions to 0.1 ppm were tested, as needed, to obtain reduced mortality.

Derepression of nitrogenase in chemostat cultures of the fast growing Rhizobium leguminosarum

Rhizobium leguminosarum is capable of nitrogen fixation in free living cultures. Nitrogenase activity can be induced when the ammonia supply of a nitrogen-limited culture, in which the oxygen concentration is regulated at 1 μm, is switched off. Assuming a nitrogen content of the cell of 12% the theoretical washout curve of such a culture can be calculated. The measured optical densities are higher than the calculated ones. In one case, 8 days after the shift, the medium supply was switched off and batch growth with molecular nitrogen occurred. Acetylene reduction started immediately in samples taken 2 days after the shift. Addition of ammonium chloride to the test vials inhibited acetylene reduction. The highest specific activities were found 5–8 days after the shift (100 nmol ethylene formed per milligram dry weight per hour). From this activity a μmax of 0.007–0.009 (generation time 76–98 h) on molecular nitrogen can be calculated. After the shift Ymannitol decreased from 33 to 23 in the first 48 h. Three days after the shift Ymannitol had a value of 15. During batch growth Ymannitol had a value of 8.

Radiometric Microbiological Assay of Vitamin B6: Assay Simplification and Sensitivity Study

Modification of a previously developed radiometric microbiological assay for vitamin B6 reduces assay complexity and time. Reduction of enzymatic treatment from 24 to 3 h essentially eliminates one day's time for the analysis of plasma samples. Use of lyophilized Kloeckera brevis cultures eliminates routine subculturing of the test organism, with no significant effect on test results. Modifications in test vial size and total volume in test vials have increased assay sensitivity to a level of 0.25 ng pyridoxine (PN), pyridoxal (PL), or pyridoxamine (PM) per vial level and decreased the amount of medium and labeled substrate (i.e., L-[1-14C]-valine), thus reducing assay cost.

Laboratory Evaluation of Igr's and Toxicants Against the Larvae of the Oriental Rat Flea, 1981

Abstract A 10-g sample of a mixture of fine sand and flea larval diet was placed in a 25-ml screwcapped vial. An appropriate concentration of technical IGR or toxicant in 500 ul of acetone was added to the mix, and after it was stirred, the acetone was evaporated at room temperature. Next, 200 ul of water was added and stirred into the mix. Twenty-five laboratory-reared 2nd stage larvae were added. Vials were then covered with 0.3 mm mesh marquisette cloth and held in separate chambers at 75% RH, 29 ± 1°C, and 8/16 dark/light cycle. Each test was replicated 2-6 times. Control vials containing the sand-diet mix were treated with the acetone only and handled in the same manner as test vials. The vials were examined weekly for 2 or 3 wk, and any cocoons were removed and placed in 3.7-ml shell vials and covered with the marquisette cloth. Twenty-one days after removal of the cocoons, any emerged fleas were killed with chloroform and counted. The highest concentration of IGR or toxicant tested was 100 ppm; dilutions to 1.0 ppb were tested, as needed, to obtained reduced mortality.

Enrichment and cryopreservation of bone marrow progenitor cells for autologous reinfusion

From 20 patients with solid tumors or acute nonlymphocytic leukemia in remission, hemopoietic progenitor cells were taken and stored in liquid nitrogen, for use in autologous bone marrow transplantation. Bone marrow aspiration resulted in a volume of 920(± 170) ml containing 16.8(± 6.0) × 10 9 nucleated bone marrow cells and 7.2(± 4.4) × 10 6 myeloid progenitor cells (CFU c). With use of the Haemonetics blood cell separator a progenitor cell-enriched fraction is obtained. This fraction is depleted of 90(± 6)% of the erythrocytes and 59(± 15)% of the neutrophils contained in the original. The original aspirate volume is reduced to one-fifth (21 ± 3%) while containing 88(+ 38)% of the original CFU c's and 52(± 11)% of the nucleated bone marrow cells. This technique of bone marrow enrichment has the advantage of a minimum of open-air contact, being independent of extensive laboratory facilities and manpower. The enriched fraction is frozen in autologous plasma and a final concentration of 10% (v/v) DMSO, using a program-controlled freezer (L'Air Liquide). Materials are stored at liquid nitrogen temperature in bags (Gambro) and test vials. Total CFU c recovery in test vials after thawing was 81(± 32)%.

Laboratory Evaluation of Igr’s and Toxicants Against the Larvae of the Oriental Rat Flea, 1977-1980

Abstract A 10-g sample of a mixture of fine sand and flea larval diet was placed in a 25-ml screwcapped vial. An appropriate concentration of technical IGR or toxicant in 500 μl of acetone was added to the mix, and after it was stirred, the acetone evaporated at room temperature. Next, 200 μl of water was added and stirred into the mix. Fifty laboratory-reared larvae of the oriental rat flea, Xenopsyllacheopis (Rothschild), in the middle of larval development (2nd instar), were added. Vials were then covered with 0.3 cm mesh marquisette cloth and held in separate chambers at the desired humidity, temperature, and light conditions. Each test was replicated 2-5 times. Control vials containing the sand-diet mix were treated with the acetone only and handled in the same manner as test vials. The vials were examined weekly for 2 or 3 weeks and any cocoons were removed and placed in 3.7 ml shell vials and covered with the marquisette cloth. Twenty-one days after removal of the cocoons, any emerged fleas were kilted with chloroform and counted. The highest concentration of IGR or toxicant tested was 500 ppm; dilutions to 0.2 ppb were tested, as needed, to obtain reduced mortality.

Application of a Limulus test device in rapid evaluation of gonococcal and nongonococcal urethritis in males.

A test device incorporating Limulus amoebocyte lysate (Mallinckrodt, Inc., St. Louis, Mo.) was developed for the rapid, presumptive diagnosis of gonococcal and nongonococcal disease in males. The device, which was evaluated in 550 men with exudative urethritis, consisted of a specimen collection syringe, a dilution reservoir containing 10 ml of pyrogen-free water, and a Limulus amoebocyte lysate single-test vial. After specimen collection, the syringe was affixed to the dilution reservoir for rapid, accurate dilution of the clinical sample. Contamination of the specimen and potential biohazards to the user were prevented. The diluted sample was then transferred (via the collection syringe) to the lysate test vial for assay of endotoxin. Various incubation times at 37 degrees C were also studied in an additional 301 male patients, and time was reduced from the standard 60 to 30 min while still retaining equivalent predictability of culture results (P less than 0.05). Of the 550 males evaluated with the test device, 366 had positive cultures for Neisseria gonorrhoeae, and 184 were negative. A sensitivity of 99.2% and a specificity of 96.7% were obtained with the test device. Overall ability to predict culture results was 98.4%. Gram-stain sensitivity and specificity were 96.4% and 99.5%, respectively, with an overall accuracy of 97.5%. There were no statistical differences between the Limulus amoebocyte lysate test and Gram stain in predicting cultures (P less than 0.05). Thus, use of the Limulus amoebocyte lysate test device would enable the private physician to make an accurate, presumptive diagnosis of gonococcal and nongonococcal disease in males with exudative urethritis within 30 min without the need of a microscope and to initiate proper therapy during the patient's initial evaluation.

Effect of blood dilution on recovery of organisms from clinical blood cultures in medium containing sodium polyanethol sulfonate

This clinical study was designed to evaluate the standard laboratory protocol that requires blood specimens be diluted with greater than or equal to 10 volumes of media. Blood was collected from hospitalized patients, and 1 ml was inoculated into each of three vials containing 2.3, 7.3, and 24 ml of BACTEC 6B aerobic medium resulting in dilutions of 1:4, 1:10, and 1:30, respectively. The three test vials were treated identically, and the study was carried out at four hospitals. Of the 2,550 sets of vials inoculated, 174 were positive with clinically significant isolates from 105 patients. There was no difference in the number of positive cultures recovered by 24 h (67%) or 48 h (90%) from any dilution. These percentages agreed with other reports from BACTEC users. The number of positive vials (139, 144, 147, respectively) at each dilution was not significantly different, indicating that all three dilutions showed equal recovery of pathogenic microorganisms. Despite this overall equality, two patients, one on antibiotic therapy, were found to have correlated cultures which failed to grow at the 1:4 dilution. This finding implies that a 1:4 dilution of blood cannot be recommended unequivocably despite the higher overall recovery rate of positive cultures.

The influence of hyper-free fatty acidemia to thyroid function determined by methods utilizing thyroxine binding proteins (author's transl)

After administration of the hypolipidemic agent 'dextran sulfate' to hyperlipidemic patients, the following data were acquired regardless of the thyroid function : the decrease of triglycerides, the increase of free fatty acids (FFA), the decrease of protein bound iodine, the increase of effective thyroxine ratio (ETR), the slight decrease of thyroid stimulating hormone, no significant change of thyroxine determined by radioimmunoassay (RIA-T4), the increase of T4 determined by competitive protein-binding analysis (CPBA-T4) and the increase of resin triiodothyronine uptake (RT3U) determined by Scholer's method.Furthermore, it was recognized that the increase of CPBA-T4 value was significantly correlative to the amount of increased FFA. Therefore, this paper was undertaken for the purpose of proving that FFA would interfere with the measurement system of commercial kits utilizing thyroxine binding proteins.It has recently been discovered that circulating FFA is mainly combined with albumin, but that oversupplied FFA is partially combined with lipoproteins or thyroxine binding globulin (TBG), and that T4 is displaced by FFA from the TBG-binding site and becomes free.In hyper-free fatty acidemic serum, after the administration of dextran sulfate, it was naturally anticipated that the amount of free type of labelled T3 must have increased in the system of saturation analysis, because FFA had already been tightly combined with the TBG site. But contrary to this expectation, the amount of separated free type of labelled T3 decreased more than in normo-free fatty acidemic serum. This paradoxical finding was explained as the result of the surface activity-like interference of FFA with the absorption by resin strip. So it was proved that RT3U (Scholer's method) would be raised by oversupplied FFA.It was noticed in this study that when endogenous T4 was extracted from serum in many commercial kits, the significant amount of FFA was also extracted by alcohol together with it. And because the extracted FFA also displaced labelled T4 from the TBG site in the test vial, the free type of labelled T4 increased more in the system of CPBA than when only endogenous T4 competed with labelled T4 from the TBG site. Thus the false elevation of CPBA-T4 was calculated in hyper-free fatty acidemic serum. And the false elevation of ETR value in the same serum was proved as the result of the interference of FFA with the measurement system.Because the interference of FFA in RIA-T4 was essentially negligible, the difference between CPBA-T4 and RIA-T4 values was significant in hyperthyroid patients with high levels of FFA.

Chloroquine sensitivity of Plasmodium falciparum in Ethiopia. II. Results of an in vitro test.

Field trials were performed in two areas of Ethiopia with the Rieckmann in vitro test for chloroquine sensitivity of Plasmodium falciparum. Blood cultures from 82 test subjects showed growth of trophozoites to the schizont stage in control vials. Growth in test vials occurred in 21 cultures incubated with chloroquine at concentrations of 0.5 nanomoles or more per ml of blood. In vitro results confirm previous results obtained with an in vivo test.

Ultramicro cuvettes for the routine laboratory adaptation for the Gilford 300 spectrophotometer.

Thermostatted adaptors have been constructed for the Sanz micro cuvette (5 mm cell path, 100 μl volume) and the Auto-Analyzer® micro cuvette (15 mm cell path, 130 μl volume) fitting the Gilford 300 spectrophotometer. The minimum amount of sample necessary to fill the cuvette is drawn into the bottom of the cuvette by means of a syringe connected to the top of the cuvette. The cuvette is emptied by pushing the sample back into the test vial after measurement.

Techniques for Increasing the Convenience and Sensitivity of Dry-Film Bioassay of Insecticide Residues with Drosophila spp.

AbstractA flightless strain of Drosophila melanogaster Meig. was used with a dry-film bioassay technique for the analysis of dieldrin residues in wheat grain. The flightless fruitflies were much more convenient to handle than a wild strain and the use of a slippery plastic barrier on collecting and sorting dishes avoided the need for immobilising flies by cold or CO2. Experimental evidence is given for the adoption of standardised breeding and handling systems for controlling certain intrinsic factors in the fly population. Also, by controlling such extrinsic factors in the bioassay system as the number of flies per test vial, replication, and holding temperature, a satisfactorily reproducible LD50 of 0.015 μg. dieldrin per vial was obtained. When this technique was applied to the analysis of dieldrin residues in wheat grain, 0.01-0.10 ppm. dieldrin could be conveniently assayed after chromatographic cleanup of a solvent extract of the grain. The accuracy of the bioassay estimates has been confirmed by gas-chromatographic analysis.