Concurrent Quantitation of Total Campylobacter and Total Ciprofloxacin-Resistant Campylobacter Loads in Rinses from Retail Raw Chicken Carcasses from 2001 to 2003 by Direct Plating at 42°C

This is the first report on the use of a normally lethal dose of ciprofloxacin in a Campylobacter agar medium to kill all ciprofloxacin-sensitive Campylobacter spp. but allow the selective isolation and quantitation of naturally occurring presumptive ciprofloxacin-resistant Campylobacter CFU in rinses from retail raw chicken carcasses (RTCC). Thermophilic-group total Campylobacter CFU and total ciprofloxacin-resistant Campylobacter CFU (irrespective of species) were concurrently quantified in rinses from RTCC by direct plating of centrifuged pellets from 10 or 50 ml out of 400-ml rinse subsamples concurrently on Campylobacter agar and ciprofloxacin-containing Campylobacter agar at 42°C (detection limit = 0.90 log₁₀ CFU/carcass). For 2001, 2002, and 2003, countable Campylobacter CFU were recovered from 85%, 96%, and 57% of RTCC, while countable ciprofloxacin-resistant Campylobacter CFU were recovered from 60%, 59%, and 17.5% of RTCC, respectively. Total Campylobacter CFU loads in RTCC rinses ranged from 0.90 to 4.52, 0.90 to 4.58, and 0.90 to 4.48 log₁₀ CFU/carcass in 2001, 2002, and 2003, respectively. Total ciprofloxacin-resistant Campylobacter CFU loads in RTCC rinses ranged from 0.90 to 4.06, 0.90 to 3.95, and 0.90 to 3.04 log₁₀ CFU/carcass in 2001, 2002, and 2003, respectively. Overall, total Campylobacter loads of 0.90 to 2.0, 2 to 3, 3 to 4, 4 to 5 log₁₀ CFU/carcass, respectively, were recovered from 16%, 32%, 26%, and 5% of RTCC tested over the 2-year sampling period. For the same period, total ciprofloxacin-resistant Campylobacter loads of 0.90 to 2.0, 2 to 3, 3 to 4, and 4 to 5 log₁₀ CFU/carcass, respectively, were recovered from 24%, 11%, 7%, and 0.2% of RTCC tested. There was a steady decline in total Campylobacter and total ciprofloxacin-resistant Campylobacter loads in RTCC rinses from 2001/2002 to 2003.     

Enhancement of cell killing by induction of apoptosis after treatment with mild hyperthermia at 42 degrees C and cisplatin.

Ohtsubo, T., Igawa, H., Saito, T., Matsumoto, H., Park, H. J., Song, C. W., Kano, E. and Saito, H. Enhancement of Cell Killing by Induction of Apoptosis after Treatment with Mild Hyperthermia at 42 degrees C and Cisplatin. Radiat. Res. 156, 103-109 (2001).We examined the interactive effects of cisplatin (1.0 microg/ml) combined with hyperthermia on cell killing and on the induction of apoptosis in IMC-3 human maxillary carcinoma cells. The cytotoxic effects of hyperthermia on IMC-3 cells at 44 degrees C were greater than at 42 degrees C, as has been reported for many other cells. The induction of apoptosis, DNA fragmentation and poly(ADP-ribose) polymerase cleavage were greater after hyperthermia at 44 degrees C for 30 min compared with treatment at 42 degrees C for 105 min, even though both of these heat doses were isoeffective in reducing cell survival to 50%. Treatment with cisplatin at 37 degrees C for up to 120 min did not result in cytotoxicity or the induction of apoptosis. The enhancement ratio for treatment with cisplatin at 42 degrees C was greater than that at 44 degrees C. More apoptosis was induced after the treatment with cisplatin at 42 degrees C compared to treatment with cisplatin at 44 degrees C. Taking these findings together, the combination of cisplatin and hyperthermia at 42 degrees C appeared to be more effective than cisplatin with hyperthermia at 44 degrees C for the induction of apoptosis in IMC-3 cells.     

Structure and mechanical properties of giant lipid (DMPC) vesicle bilayers from 20 degrees C below to 10 degrees C above the liquid crystal-crystalline phase transition at 24 degrees C

We have used micromechanical tests to measure the thermoelastic properties of the liquid and gel phases of dimyristoylphosphatidylcholine (DMPC). We have found that the rippled P beta' phase is only formed when a vesicle is cooled to temperatures below the main acyl chain crystallization transition, Tc, under zero or very low membrane tension. We also found that the P beta' surface ripple or superlattice can be pulled flat under high membrane tension into a planar structure. For a ripple structure formed by acyl chains perpendicular to the projected plane, the projected area change that results from a flattening process is a direct measure of the molecular crystal angle. As such, the crystal angle was found to increase from about 24 degrees just below Tc to about 33 degrees below the pretransition. It was also observed that the P beta' superlattice did not form when annealed L beta' phase vesicles were heated from 5 degrees C to Tc; likewise, ripples did not form when the membrane was held under large tension during freezing from the L alpha phase. Each of these three procedures could be used to create a metastable planar structure which we have termed L*beta' since it is lamellar and plane-crystalline with acyl chains tilted to the bilayer plane. However, we show that this structure is not as condensed as the L beta' phase below 10 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)     

The maintenance of respiratory control at 25 degrees C by mitochondria from various animal and plant sources.

1. Mitochondria from four different animal and five different plant sources exhibit a wide variation in their capacity to maintain respiratory control at 25 degrees C. 2. Beef heart mitochondria, and pear and avocado fruit mitochondria exhibit the longest retention of respiratory control extending to periods of approximately 80 and 40 hr, respectively.     

The effects of fabric air permeability and moisture absorption on clothing microclimate and subjective sensation in sedentary women at cyclic changes of ambient temperatures from 27 degrees C to 33 degrees C

The present paper aimed at learning the effects of two different levels of air permeability and moisture absorption on clothing microclimate and subjective sensation in sedentary women. Three kinds of clothing ensemble were investigated: 1) polyester clothing with low moisture absorption and low air permeability (A clothing); 2) polyester clothing with low moisture absorption and high air permeability (B clothing); and 3) cotton clothing with high moisture absorption and high air permeability (C clothing). After 20 min of dressing time, the room temperature and humidity began to rise from 27 degrees C and 50% rh to 33 degrees C and 70% rh over 20 min, and it was maintained for 30 min (Section I); it then began to fall to 27 degrees C and 50% rh over 20 min, and it was maintained there for 20 min (Section II). The subject sat quietly on a chair for 110 min. The main findings are summarized as follows: 1) The clothing surface temperature was significantly higher in C clothing than in B clothing during section I, but it was significantly higher in B clothing than in C clothing during section II. 2) Although the positive relationship between the microclimate humidity and forearm sweat rate was significantly confirmed in all three kinds of clothing, the microclimate humidity at the chest for the same sweat rate was lower in C clothing than in A and B clothing. These results were discussed in terms of thermal physiology.     

Improvement of modified charcoal-cefoperazone-deoxycholate agar by supplementation with a high concentration of polymyxin B for detection of Campylobacter jejuni and C. coli in chicken carcass rinses

Modified charcoal-cefoperazone-deoxycholate agar (mCCDA) was improved by supplementation with a high concentration of polymyxin B. The ability of the supplemented medium to isolate Campylobacter jejuni and C. coli from chicken carcass rinses was compared to that of Campy-Cefex agar and mCCDA. Modification of mCCDA with increased polymyxin B yielded a significantly (P < 0.05) higher isolation rate and greater selectivity than those achieved using Campy-Cefex agar and mCCDA.     

Cryopreservation and ensuing in vitro fertilization ability of boar spermatozoa from epididymides stored at 4 degrees C

The influence of prolonged storage of boar epididymides on post-thaw sperm motility, and in vitro fertilization was evaluated. Twenty pairs of epididymides were obtained from Large White boars, and spermatozoa from one of each of the pairs were immediately collected and frozen (control group). The remaining epididymides were cooled to 4 degrees C and stored for 1, 2 or 3 d, after which spermatozoa were collected and frozen (experimental groups Day 1, 2 and 3, respectively). Sperm motility was maintained throughout the dilution procedure and then dropped (P < 0.01) after freezing and thawing. During storage the motility of nonfrozen spermatozoa decreased significantly (P < 0.01), reaching a value equal to that of frozen-thawed spermatozoa on Day 3. In vitro fertilization experiments revealed significantly (P < 0.05) lower penetration rates using Day 1, 2 and 3 stored spermatozoa (12, 13 and 2%, respectively) than that of the control group (40%). Oocyte penetration ability seemed to be reflected by acrosome integrity. However, the motility of spermatozoa with the ability to penetrate oocytes in Day 1 and Day 2 groups did not differ from that of the controls. The motility of spermatozoa lacking penetration ability, on the other hand, gradually decreased as the storage period was prolonged. This suggests that the sperm motility and penetration ability are affected by different mechanisms during the cold storage of epididymides. Finally, control and experimental groups exhibited high incidences of monospermic penetration (64 to 90%) and of male pronuclear formation (67 to 71%). These data suggest that cryopreservation of spermatozoa from boar epididymides stored at 4 degrees C for 1 to 2 d can be used for conserving male germ cells when epididymal spermatozoa can not be collected immediately and cryopreserved.     

The bacterial flora of vacuum-packed cold-smoked salmon stored at 7 degrees C, identified by direct 16S rRNA gene analysis and pure culture technique

AIMS: The indigenous flora of freshly chilled cold-smoked salmon just after the vacuum packaging, and the spoilage flora after storage, in vacuum package at 7 degrees C for 19 days, were to be investigated with two different sampling strategies. METHODS AND RESULTS: Identification was performed using 16S rRNA sequencing of both isolated bacteria and bacterial DNA from tissue extract. The indigenous flora of fresh cold-smoked vacuum-packed salmon was dominated by, in order, Brochothrix thermosphacta, Yersinia ruckeri, Photobacterium and Carnobacterium, whereas the spoilage flora of the same product stored at 7 degrees C for 19 days was dominated by Lactobacillus and Photobacterium. The two sampling strategies showed similar results on the fish flora. Several new types of Photobacterium sequences, closely related to Photobacterium iliopiscarium and Photobacterium phosphoreum, were found from both the freshly processed and the stored salmon, indicating that smoked salmon harbours at least three different, as yet unknown, Photobacterium species. CONCLUSIONS: Ten per cent of the bacterial flora multiplying on chilled, vacuum-packed, cold-smoked salmon comprised unknown species. The two sampling strategies complement each other. SIGNIFICANCE AND IMPACT OF THE STUDY: As cold-smoked salmon is consumed without heat-treatment, the presence of undefined bacteria in high numbers should be considered in public health assessments.     

Variability in response to UV-B among species and strains of Metarhizium isolated from sites at latitudes from 61 degrees N to 54 degrees S.

The effects of irradiances of 920 and 1200 mW m(-2) (biologically effective weighted irradiance) were examined in 2 Metarhizium album strains, 26 M. anisopliae strains, 1 M. flavoviride strain, and 1 M. taii strain isolated from sites located at latitudes from 61 degrees N to 54 degrees S. Conidia were exposed to UV-B from 1 to 6 h and subsequently examined for relative percentage culturability. Total dosage received at the end of the exposure periods ranged from 3.3 to 19.9 kJ m(-2) for the lower irradiance and from 4.3 to 25.9 kJ m(-2) for the higher irradiance. Both the irradiance values and the doses are environmentally realistic and can be observed even in temperate regions. The relationships between latitude of origin and UV-B tolerance were compared for the two levels of irradiance for the data from 1 and 2 h exposure. Exposure to both irradiances drastically reduced the relative percentage culturability of all strains. Tolerance to UV-B varied widely among strains and high variation was observed for both irradiances after all periods of exposure. After 1 h of exposure, a difference between the two irradiance levels was detectable, and this difference was magnified at longer irradiations. A significant quadratic relationship of decreasing UV-B tolerance with increasing latitude was observed after exposure of 1 and 2 h. The shape of the relationship did not differ for the two levels of irradiance. Also, we studied the effect of 1200 mW m(-2) irradiance on conidial germination time in 1 M. album strain, 7 M. anisopliae strains, and 1 M. taii strain. Exposure to UV-B delayed the germination of surviving conidia of all strains. In general, the delay in germination was directly proportional to the dose.     

Confirmation of Escherichia coli and its distinction from Klebsiella species by gas and indole formation at 44 and 44.5 degrees C

AIMS: In the enumeration of coliform bacteria, confirmation of Escherichia coli has been based upon gas and indole production at the elevated incubation temperature. The test for gas production has recently been questioned. The aim of this study was to investigate the impact of gas production test on the reliability of confirmation of E. coli. METHODS AND RESULTS: The impact of several media on growth, gas and/or indole formation was tested at 44 and 44.5 degrees C using 547 environmental isolates. These were mainly E. coli, Klebsiella pneumoniae, K. oxytoca and Enterobacter cloacae strains. Another set of 250 faecal and environmental klebsiellae were tested for their maximum temperature for growth (Tmax) and for gas formation. Escherichia coli and even K. pneumoniae grew well in all the media, but gas production was more dependent on the medium used. Growth of the mainly gas negative Ent. cloacae and K. oxytoca strains was still more sensitive to the medium and incubation conditions. Tryptophan salt broth was the most productive medium for the indole test, followed by lauryl tryptose mannitole and tryptone mannitol ricinoleate broth (TRM). Tmax of K. oxytoca was clearly lower than Tmax of K. pneumoniae but a rather high fraction of its isolates produced indole at 44.5 degrees C. CONCLUSIONS: False-positive E. coli confirmation is possible if gas production is not tested for and the confirmation is based on indole test only. SIGNIFICANCE AND IMPACT OF THE STUDY: Erroneous positive results on routine analysis for E. coli can occur.     

Ultrastructural and hormonal metabolic studies of rat liver maintained in vitro by perfusion at 30 degrees C and 37 degrees C: a time course study by TEM, SEM and RIA

Isolated rat liver perfusion system has been extensively used for metabolic and functional studies. Results derived from the application of this system may reflect true biochemical changes but they may also be associated with some structural changes. This study was undertaken to correlate the cytological changes and functional integrity of isolated rat liver perfused in vitro at normal physiological temperature (37 degrees C) and 30 degrees C, using a non-recirculating system. The livers were perfused for 3 hours with modified Ham's F10 culture medium supplemented with thyroxine hormone (T4). The hepatocyte structural integrity was studied by light microscopy, transmission and scanning electron microscopy. The triiodothyronine (T3) and T4 hormones in the perfusion medium and the effluent fractions were assessed by radioimmunoassay. The livers perfused at 30 degrees C remained morphologically intact at the ultrastructural level for 3 hours whilst at 37 degrees C, hepatocytes in the centrilobular zone exhibited marked structural alterations. The percentage of T4 uptake was significantly higher (P less than 0.01) in livers perfused at 30 degrees C (50.8 +/- 7.7% vs 38 +/- 7.7%, 37 degrees C), but the net T3 output (3.16 +/- 1.04 micrograms) and the conversion of T4 to T3 (4 +/- 0.62%) were significantly higher (P less than 0.001) in livers perfused at 37 degrees C in comparison to livers perfused at 30 degrees C (1.61 +/- 0.84 micrograms and 1.68 +/- 0.76%, respectively). In conclusion, at 30 degrees C the hepatic T4 uptake is not inhibited, but the rate of T4 to T3 conversion has decreased, additionally the livers remain morphologically well preserved throughout the experimental period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Permeability and damage of the erythrocyte membrane at -1 degree C to -9 degrees C shown by the NMR relaxation method

Amount of inter--and extracellular unfrozen water in the intact human erythrocytes as well as tau a, "a life time" of water molecules in these cells, have been determined. The progressive compression of the erythrocytes during freezing them as deep as -5 degrees C has been found to submit to the ideal osmometer law. The membrane impermeability to Mn2+ ions has been disturbed when the temperature falls to -7 degrees C and below, the erythrocytes reaching "the minimal volume".     

Five-year stability study of free and total prostate-specific antigen concentrations in serum specimens collected and stored at -70 degrees C or less

The stability of total (t) and free (f) prostate-specific antigen (PSA) in male serum specimens stored at -70 degrees C or lower temperature for 4.7 to 4.9 years was studied. Until now, the stability of these analytes in serum has not been evaluated systematically beyond 2 years of storage at -70 degrees C. Aliquots of frozen serum were thawed in 2001 and 2006 and assayed for tPSA and fPSA using a Dade Behring Dimension(R) RxL analyzer and reagents. tPSA values ranged from 0.07 to 69.94 and 0.00 to 69.83 ng/mL in 2001 and 2006, respectively, whereas fPSA values for the tested specimens ranged from 0.02 to 5.72 and 0.00 to 5.92, respectively. Deming regression analyses showed agreement in assay values over time as tPSA values yielded a slope of 1.0112 and a y-intercept of 0.0195; fPSA values produced a slope 1.0538 and a y-intercept of -0.0442; f/tPSA values yielded a slope of 0.9631 and a y-intercept of 0.1195. A Bland-Altman analysis of the data demonstrated analyte and ratio stability over this time period. We conclude that serum, when collected properly and stored at -70 degrees C or lower temperature, may be used for tPSA and fPSA clinical studies for at least 5 years after collection.