Particulate oxidative burden associated with firework activity

Firework events are capable of inducing particulate matter (PM) episodes that lead to exceedances of regulatory limit values. As short-term peaks in ambient PM concentration have been associated with negative impacts on respiratory and cardiovascular health, we performed a detailed study of the consequences of firework events in London on ambient air quality and PM composition. These changes were further related to the oxidative activity of daily PM samples by assessing their capacity to drive the oxidation of physiologically important lung antioxidants including ascorbate, glutathione and urate (oxidative potential, OP). Twenty-four hour ambient PM samples were collected at the Marylebone Road sampling site in Central London over a three week period, including two major festivals celebrated with pyrotechnic events: Guy Fawkes Night and Diwali. Pyrotechnic combustion events were characterized by increased gas phase pollutants levels (NO(x) and SO(2)), elevated PM mass concentrations, and trace metal concentrations (specifically Sr, Mg, K, Ba, and Pb). Relationships between NO(x), benzene, and PM(10) were used to apportion firework and traffic source fractions. A positive significant relationship was found between PM oxidative burden and individual trace metals associated with each of these apportioned source fractions. The level of exposure to each source fraction was significantly associated with the total OP. The firework contribution to PM total OP, on a unit mass basis, was greater than that associated with traffic sources: a 1 μg elevation in firework and traffic PM fraction concentration was associated with a 6.5 ± 1.5 OP(T) μg(-1) and 5.2 ± 1.4 OP(T) μg(-1) increase, respectively. In the case of glutathione depletion, firework particulate OP (3.5 ± 0.8 OP(GSH) μg(-1)) considerably exceeded that due to traffic particles (2.2 ± 0.8 OP(GSH) μg(-1)). Therefore, in light of the elevated PM concentrations caused by firework activity and the increased oxidative activity of this PM source, there is value in examining if firework derived PM is related to acute respiratory outcomes.     

叶酸代谢抑制剂对小鼠骨髓基质细胞增殖和分化的影响

采用四甲基偶氮唑蓝（methyl thiazolyl tetrazolium,MTT）法、细胞形态分析法及诱导分化法结合油红O染色法研究叶酸代谢中二氢叶酸还原酶抑制剂甲氨喋呤（methotrexate,MTX）、甲氨苄啶（trimethoprim,TMP）和乙胺嘧啶（pyrimethamine,PTM）对OP9小鼠骨髓基质细胞增殖和分化的影响,探讨叶酸代谢与脂质合成的关系。MTT实验结果显示,在一定浓度范围内,3 种叶酸抑制剂均能抑制OP9细胞增殖,并呈现一定的剂量-效应依赖关系。且3 种叶酸抑制剂在高浓度时对OP9细胞有毒性作用。倒置显微镜观察和油红O染色检测结果显示,TMP在500～1 000 μmol/L浓度范围内对OP9细胞分化为脂肪细胞具有抑制作用。荧光定量聚合酶链式反应分析表明,TMP会使叶酸代谢途径中二氢叶酸还原酶和亚甲基四氢叶酸脱氢酶的转录水平发生下调,这可能是TMP抑制脂肪细胞诱导分化的原因。     

Changes in markers of epithelial permeability and inflammation in chronic smokers switching to a nonburning tobacco device (Eclipse).

Eclipse, produced by R. J. Reynolds Tobacco Company, is a potential reduced exposure product (PREP) that heats rather than burns tobacco. We hypothesized that switching to Eclipse would result in relative normalization of pulmonary epithelial permeability, airway inflammation, and blood leukocyte activation in current smokers. We assessed 10 healthy smokers (aged 21-50 years, 19+/-8 pack-years) at baseline and after 2 and 4 weeks of switching to Eclipse, for symptoms, pulmonary function, airway inflammation, lung clearance of (99m)technicium-diethylenetriaminepentaacetic acid, and blood leukocyte activation and production of reactive oxygen species. Values were compared before and after Eclipse use and with those of healthy, lifetime nonsmokers (aged 18-53 years). Compared with baseline values before switching to Eclipse, lung permeability half-time increased from 33+/-3 to 43+/-6 min (p = .017) after 2 weeks and to 44+/-7 min (p = .10) after 4 weeks of Eclipse use. Carboxyhemoglobin levels increased from 5%+/-2% to 7%+/-2% (p<.01) at 4 weeks. Compared with smoking the usual brand of cigarettes, after smoking Eclipse the percentage of natural killer cells, the expression of intercellular adhesion molecule-1 on monocytes, and the expression of CD45RO on T cells showed significant improvement. However, expression of other surface markers, notably CD23 on monocytes, became more abnormal. Production of reactive oxygen species by smokers' neutrophils and monocytes increased further with Eclipse use. We found no significant effects on pulmonary function, cells in induced sputum, or exhaled nitric oxide. Switching to Eclipse reduces alveolar epithelial injury in some smokers but may increase carboxyhemoglobin levels and oxidative stress.     

Available human feeder cells for the maintenance of human embryonic stem cells

Mouse embryonic fibroblasts (MEFs) have been previously used as feeder cells to support the growth of human embryonic stem cells (hESCs). In this study, human adult uterine endometrial cells (hUECs), human adult breast parenchymal cells (hBPCs) and embryonic fibroblasts (hEFs) were tested as feeder cells for supporting the growth of hESCs to prevent the possibility of contamination from animal feeder cells. Cultured hUECs, hBPCs and hEFs were mitotically inactivated and then plated. hESCs (Miz-hES1, NIH registered) initially established on mouse feeder layers were transferred onto each human feeder layer and split every 5 days. The morphology, expression of specific markers and differentiation capacity of hESCs adapted on each human feeder layer were examined. On hUEC, hBPC and hEF feeder layers, hESCs proliferated for more than 90, 50 and 80 passages respectively. Human feeder-based hESCs were positive for stage-specific embryonic antigen (SSEA)-3 and -4, and Apase; they also showed similar differentiation capacity to MEF-based hESCs, as assessed by the formation of teratomas and expression of tissue-specific markers. However, hESCs cultured on hUEC and hEF feeders were slightly thinner and flatter than MEF- or hBPC-based hESCs. Our results suggest that, like MEF feeder layers, human feeder layers can support the proliferation of hESCs without differentiation. Human feeder cells have the advantage of supporting more passages than when MEFs are used as feeder cells, because hESCs can be uniformly maintained in the undifferentiated stage until they pass through senescence. hESCs established and/or maintained under stable xeno-free culture conditions will be helpful to cell-based therapy.     

Behavior of Trp-P-1 and its metabolites in rat excreta

To study of the behavior of Trp-P-1 and its metabolites in rat feces and urine, rats were orally administered with Trp-P-1 (750, 1,500 and 2,500 micrograms/rat), and excreted Trp-P-1 was analyzed using HPLC assay and bacterial mutagenicity assay. The extraction of Trp-P-1 from urine was performed by using the chloroform extraction method, and blue rayon was used for the extraction from feces. When Trp-P-1 was added to rat feces and urine, the recoveries of Trp-P-1 were 85.9 +/- 3.9% and 91.3 +/- 3.7%, respectively. The extracts of feces and urine from rats administered with Trp-P-1 were individually fractionated by thin layer chromatography on C18 gel. The major mutagenic zone corresponding to Trp-P-1 was found at Rf 0.09 in both extracts, while the feces extract gave two additional mutagenic zones at Rf 0.15 and 0.20. More than 97% of the fecal mutagenic activity was due to unchanged Trp-P-1. In rats administered with 750 micrograms of Trp-P-1, the amount of extracted Trp-P-1 and the number of His+ colonies induced by whole excreta were 81.6 +/- 7.1 micrograms (n = 6) and (432 +/- 77) x 10(4) for feces, and 28.7 +/- 4.9 micrograms and (171 +/- 28) x 10(4) for urine. The recoveries of Trp-P-1 in the feces and urine were 10.8 +/- 0.9% and 3.8 +/- 0.7% by HPLC analysis, and 11.1 +/- 2.0% and 4.4 +/- 0.7% by mutagenicity assay respectively. The results of the two assays seemed to show similar patterns of recovery.     

Subclinical mastitis in dairy cows in Swiss organic and conventional production systems

The objective was to compare the prevalence of subclinical mastitis (SM) and of udder pathogens in 60 Swiss organic (OP) and 60 conventional production systems (CP). Cows (n=970) were studied for SM prevalence and udder pathogens at median 31 d and 102 d post partum. Cows showing a >or=1+ positive California Mastitis Test (CMT) in at least one quarter were considered to have SM. Cow-level prevalences of SM for visits at 31 d and 102 d post partum (39% and 40% in OP and 34% and 35% in CP) were similar, but quarter-level prevalences of SM were higher (P<0.02) in OP than CP (15% and 18% in OP and 12% and 15% in CP). Median somatic cell counts in milk at 31 d post partum were higher (P<0.05) in OP than CP cows (43000 and 28000 cells/ml, respectively), but were similar at 102 d post partum in OP and CP cows (45000 and 38000 cells/ml, respectively). In milk samples from quarters showing a CMT reaction >or=2+ the prevalences of coagulase negative staphylococci were lower (P<0.05) at 102 d post partum, whereas prevalences of non-agalactiae streptococci were higher (P<0.05) in OP than in CP cows at 31 d and 102 d post partum. In conclusion, under Swiss conditions, subclinical mastitis is a greater problem in organic than in conventional production systems, but differences are not marked.     

Differences in heat tolerance between preimplantation embryos from Brahman, Romosinuano, and Angus breeds

Exposure to 41 degrees C reduces development of embryos of heat-sensitive breeds (Holstein and Angus) more than for embryos of the heat-tolerant Brahman breed. Here it was tested whether embryonic resistance to heat shock occurs for a thermotolerant breed of different genetic origin than the Brahman. In particular, the thermal sensitivity of in vitro produced embryos of the Romosinuano, a Bos taurus, Criollo-derived breed, was compared to that for in vitro produced Brahman and Angus embryos. At d 4 after insemination, embryos > or = 8 cells were randomly assigned to control (38.5 degrees C) or heat shock (41 degrees C for 6 h) treatments. Heat shock reduced the proportion of embryos that developed to the blastocyst stage on d 8 after insemination. At 38.5 degrees C, there were no significant differences in development between breeds. Among embryos exposed to 41 degrees C, however, development was lower for Angus embryos than for Brahman and Romosinuano embryos. Furthermore, an Angus vs. (Brahman + Romosinuano) x temperature interaction occurred because heat shock reduced development more in Angus (30.3 +/- 4.6% at 38.5 degrees C vs. 4.9 +/- 4.6% at 41 degrees C) than in Brahman (25.1 +/- 4.6% vs. 13.6 +/- 4.6%) and Romosinuano (28.3 +/- 4.1% vs. 17.5 +/- 4.1%). Results demonstrate that embryos from Brahman and Romosinuano breeds are more resistant to elevated temperature than embryos from Angus. Thus, the process of adaptation of Brahman and Romosinuano breeds to hot environments resulted in both cases in selection of genes controlling thermotolerance at the cellular level.     

The 'GO' system--a novel method of microculture for in vitro development of mouse zygotes to the blastocyst stage

A novel system of in vitro culture termed the 'glass oviduct' or 'GO' culture system is described. Mouse zygotes were cultured in pairs to the blastocyst stage in open-ended 1 microl glass capillaries. 'GO' culture supported the development of significantly more hatching or hatched blastocysts than did a standard microdroplet (10 zygotes per 20 microl) control culture (48.3 versus 3.3%, respectively). 'GO' bslastocysts contained significantly larger populations of cells (92+/-3 versus 75+/-3), and inner cell mass (25+/-1 versus 21+/-1) and trophectoderm (68+/-2 versus 53+/-3) subpopulations, compared with microdroplet-derived blastocysts. Before blastulation, 'GO'-derived morulae were found to contain significantly more cells than microdroplet-derived morulae (27+/-0.7 versus 14+/-0.5). After implantation, 'GO' blastocysts formed fetuses at a similar rate to microdroplet-derived blastocysts (55 versus 62%), but at a lower rate than blastocysts derived in vivo (80%). 'GO'- and microdroplet-derived fetuses were similar in wet weight to each other (0.412 and 0.415 g, respectively) but were heavier than fetuses derived from flushed blastocysts (0.390 g). An additional experiment investigated whether the beneficial effect of 'GO' culture was due to the significantly increased embryo density. Proportions of hatching or hatched blastocysts after 'GO' culture (50%) were higher than after standard microdroplet culture (7.6%), but were not different from culture in high embryo density microdroplets (20 zygotes per 10 microl; 42%). 'GO' blastocysts contained more cells (79.6+/-2.1) than did standard microdroplet-derived blastocysts (68.7+/-2.0), but were similar to high density microdroplet-derived blastocysts (85.8+/-2.7). Similarly, 'GO' blastocysts contained more trophectoderm cells (62.2+/-2.0) than did standard microdroplet-derived blastocysts (52.7+/-1.7), but were similar to the high density microdroplet blastocysts (68.8+/-2.5). Numbers of inner cell mass cells ('GO', standard microdroplet and high density microdroplet culture) were not different from each other (17.4+/-0.5, 16+/-0.5 and 17+/-0.4, respectively). In conclusion, the 'GO' culture system represents an alternative method to the microdroplet system for small numbers of preimplantation embryos, without detriment to implantation potential.     

Differences in splicing of mRNA encoding LH receptor in theca cells according to breeding season in ewes

Splice variants of mRNA encoding the LH receptor (LHR) during follicular development were characterized in cyclic and non-cyclic ewes. Granulosa and theca cells were collected from individual follicles. After amplification by RT-PCR of a region situated between exon 9 and exon 11 of the LHR gene, three distinct bands, LHR1 (full length), LHR2 (deletion of exon 10), LHR3 (deletion of 262 bp in exon 11), were observed in the granulosa and theca cells of ovine antral follicles of various sizes (2.5-6.0 mm). Expression of LHR mRNA in theca cells varied with the annual cycle of reproduction (P < 0.001), and was highly expressed in all classes of follicle collected from anoestrous ewes (1.3 +/- 0.1, n = 8 in small follicles; 1.8 +/- 0.2, n = 8 in medium follicles; 1.7 +/- 0.3, n = 4 in large follicles; arbitrary units) compared with follicles collected from oestrous ewes (0.19 +/- 0.06, n = 8 in small follicles; 0.2 +/- 0.04, n = 9 in medium follicles; 0.18 +/- 0.04, n = 5 in large follicles). During the breeding season, no differences in the relative expression of the different splice variants were observed according to follicle size. In contrast, during anoestrus, LHR3 mRNA was significantly more abundant in large (6.0-6.5 mm) and medium (4.0-5.5 mm) than it was in small (2.5-3.5 mm) follicles. These results indicate that RNA alternative splicing plays a role in the seasonal and physiological control of LH receptor expression in theca cells.     

Chromosome V loss due to centromere knockout or MAD2-deletion is immediately followed by restitution of homozygous diploidy in Saccharomyces cerevisiae

To investigate the possibility of inducing specific chromosome loss by centromere deletion in eukaryotic cells, the yeast diploid strain ZG1, carrying three pairs of heterozygous marker genes (CAN1(S)/can1(R), URA3/Deltaura3, hphMX4/HIS1), widely spread on both arms of chromosome V, was constructed. One of the two centromeres V of ZG1 was replaced by the LEU2 gene via the well-established PCR-mediated knockout technique. After DNA transformation, putative yeast colonies that showed loss of heterozygosity (LOH) for the three markers of chromosome V (CAN1(S) URA3 hphMX4) were identified among the colonies selected for leucine prototrophy. Phenotypic tests, colony-PCR and Southern blot analysis of these cells demonstrated the physical loss of the CAN1(s), URA3, and hphMX4 marker genes from the genome. Further tetrad analysis results were consistent with this conclusion; however, four-spore viability indicated a normal chromosome number of these transformants. To verify the diploidy of the selected chromosome V, the HIS1 gene was deleted with a standard KanMX4 knockout DNA cassette. The resulting heterogeneity of the HIS1/KanMX4 markers, together with quantitative PCR and densitometric analysis on chromosome V, confirmed its diploid complement, thereby indicating that an endoreduplication event had taken place. Restitution of diploidy also occurred in MAD2-deleted strains undergoing higher rates of spontaneous chromosome V loss, indicating a more general phenomenon that is undetectable by phenotypic analysis alone.     

Amino acid requirements for maturation of rhesus monkey (Macacca mulatta) oocytes in culture

This study evaluated the effects of different amino acid formulations on supporting meiotic and cytoplasmic maturation of rhesus monkey (Macacca mulatta) oocytes in vitro. Five hundred and forty-six cumulus-oocyte complexes (COCs) aspirated from unstimulated adult monkey follicles (> or = 1000 microm in diameter) were cultured in either modified Connaught Medical Research Laboratories 1066 medium (mCMRL-1066) or in one of eight chemically defined media (modified basic medium 5 supplemented with 5.5 mmol glucose l(-1), 0.003 mmol pantothenic acid l(-1) and different amino acid formulations) as below: (1) modified basic medium 5 (mBM5) containing no amino acid; (2) mBM5 + 0.2 mmol glutamine l(-1); (3) mBM5 + 11 amino acids from hamster embryo culture medium 6 (HECM-6) (11 AA); (4) mBM5 + Eagle's non-essential amino acids (NEA); (5) mBM5 + NEA + 0.2 mmol glutamine l(-1); (6) mBM5 + Eagle's essential amino acids (EA) without glutamine; (7) mBM5 + EA + 0.2 mmol glutamine l(-1); (8) mBM5 + Eagle's 20 amino acids (20 AA) + 0.2 mmol glutamine l(-1); and (9) mCMRL-1066 (control). All media contained FSH, LH, oestradiol and progesterone. After maturation, mature oocytes were subjected to the same fertilization and embryo culture procedures. COCs matured in treatment 5 had greater potential to progress to metaphase II (66%; P < 0.05) than did those in treatments 1 (37.3%), 2 (48.3%), 3 (41%), 6 (41%) and 9 (43%). Oocytes matured in treatment 8 had the best morula (53%) and blastocyst (18%) developmental responses (P < 0.05). The lowest (P < 0.05) morula and blastocyst developmental responses were obtained from COCs matured in treatments 1 (0%) and 6 (8%). The other media supported intermediate embryonic development (range 11-38% of morula and blastocyst). These results indicate that the choice of amino acids affects the competence of oocyte maturation and that Eagle's 20 AA with 0.2 mmol glutamine l(-1) is more efficient than the other amino acid formulations for maturation of rhesus monkey oocytes.     

Distribution and behavior of nonylphenol, octylphenol, and nonylphenol monoethoxylate in Tokyo metropolitan area: their association with aquatic particles and sedimentary distributions

Distributions of alkylphenols (APs) [i.e., nonylphenol (NP), octylphenol (OP)], and nonylphenol monoethoxylate (NP1EO) in wastewater effluents, river water, and riverine and bay sediments in the Tokyo metropolitan area were demonstrated. During sewage treatments, NP and OP were efficiently removed from the sewage effluents through activated sludge treatments. Greater removal for NP (93% on average) than OP (84% on average) was consistent with their partitioning behavior to particles in primary and secondary effluents. NP concentrations in the river water samples ranged from 0.051 to 1.08 microg/L with higher concentrations in summer and spring than in colder seasons. In the river water samples, approximately 20% of NP was found in the particulate phase. Organic carbon-normalized apparent partition coefficients (K'OC) for NP (10(5.22 +/- 0.38)) and OP (10(4.65 +/- 0.42)) were 1 order of magnitude higher than those expected from their octanol-water partition coefficients (K(OW)), indicating strong affinity of APs to aquatic particles. Among NP isomers, no significant differences in their K'OC values were suggested. This is consistent with surprisingly uniform isomer peak profiles among the technical standard and all the environmental samples analyzed. NP and OP were widely distributed in the river sediments in Tokyo, and relatively high concentrations (0.5-13.0 microg/g dry) of NP were observed in a long reach (approximately 10 km) in the Sumidagawa River. In situ production of APs in the river sediment was suggested. Seaward decreasing trend in APs concentration was observed from the estuary to the Tokyo Bay. APs were well preserved in a sediment core collected from the bay. The profile shows subsurface maximum of AP concentrations in the layer deposited around the mid-1970s. The recent decrease in AP concentrations can be attributed to the legal regulation of industrial wastewater in the early 1970s.     

Effects of drying process on antioxidant activity of purple carrots

Purple carrot was analysed for its antioxidant activity by measuring its scavenging effect on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical. The amount of purple carrot necessary to decrease by 50% the initial DPPH concentration (EC50) was found 30.23 +/- 5.17 (mg sample/mg DPPH). Effects of the dehydration process on the antioxidant activity of purple carrots were also determined after dehydration by using tray drier and microwave+tray drier combination. Purple carrots were cleaned, washed, sorted, sliced, and blanched in water at 98 +/- 1 degree C for 2 min. Then half of the samples were dehydrated in microwave (45 min) and tray drier (105 min) combination, and others were dehydrated in tray drier (150 min) until reaching the constant weight. Raw, blanched and dehydrated purple carrots were compared for their antioxidant activity and total anthocyanin contents, color values (L*, a*, b*, C*, H degrees) and dry matter contents. The antioxidant activity as measured by DPPH, EC50 value ranged from 7.80 to 30.23 of processed and raw carrots where the H degrees values were changed from -3.68 to -23.96 corresponding to a bluish hue.     

Availability of blueberry phenolics for microbial metabolism in the colon and the potential inflammatory implications

Blueberries are a rich source of phenylpropanoid-derived phytochemicals, widely studied for their potential health benefits. Of particular interest for colonic health are the lower molecular weight phenolic acids and their derivatives, as these are the predominant phenolic compounds detected in the colon. Blueberries contained a wide variety of phenolic acids, the majority of which (3371.14 +/- 422.30 mg/kg compared to 205.06 +/- 45.34 mg/kg for the free phenolic acids) were attached to other plant cell-wall components and therefore, likely to become available in the colon. Cytokine-induced stimulation of the inflammatory pathways in colon cells was four-fold up-regulated in the presence of the free phenolic acid fraction. Incubation of the bound phenolic acids with human faecal slurries resulted in qualitative and quantitative differences in the phenolic compounds recovered. The metabolites obtained by incubation with faecal slurries from one volunteer significantly decreased (1.67 +/- 0.69 ng/cm(3)) prostanoid production, whereas an increase (10.78 +/- 5.54 ng/cm(3)) was obtained with faecal slurries from another volunteer. These results suggest that any potential protective effect of blueberry phenolics as anti-inflammatory agents in the colon is a likely result of microbial metabolism. Studies addressing a wide-range of well-characterised human volunteers will be required before such health claims can be fully established.     

Buffalo-milk enzyme levels, their sensitivity to heat inactivation, and their possible use as markers for pasteurization

The activities and rates of inactivation of four enzymes in raw buffalo milk were measured in relation to the process of heating to determine the value of these enzymes as markers for the evaluation of milk pasteurization. The activities of the enzymes alkaline phosphatase (ALP), lactic dehydrogenase (LDH), gamma-glutamyltransferase (GGT), and aspartate aminotransferase (AST) were measured before and after heating at 50, 60, 70, and 80 degrees C for 1, 3, 5, 10, 20, and 30 min. The enzyme GGT showed the highest activity (712 +/- 601 IU/liter), followed by LDH (386 +/- 183 IU/liter), ALP (295 +/- 164 IU/liter), and AST (18 +/- 4 IU/liter). Heating the milk at 50 degrees C for 1 to 30 min resulted in no effect on the activity of any of the enzymes. At 60 degrees C, ALP showed the highest sensitivity to heat inactivation, whereas all other enzymes showed resistance. At 70 degrees C, ALP activity was abolished completely after 1 min, whereas GGT and LDH lost most activity after 10 min, and AST still maintained 50% activity even after 30 min. At 80 degrees C, the activities of LDH and GGT were lost, whereas AST still retained some of its activity. The results suggest that in addition to ALP, LDH and GGT, but not AST, are potential markers for heat denaturation in buffalo milk, with GGT having the advantage that its concentration is the highest.     

Evaluation of immunomagnetic separation and plating media for recovery of Salmonella from meat

Immunomagnetic separation (IMS) was compared with selective enrichment in selenite cystine (SC) broth for isolation of Salmonella from 86 artificially contaminated ground beef samples. Both Rambach agar (RA) and Hektoen enteric (HE) agar were used as selective plating media. The highest count of Salmonella colonies per plate was obtained after enrichment in SC broth and plating on RA (mean value: 111.1+/-58.1 CFU per plate); the lowest count was obtained after IMS and plating on HE agar (mean value: 65.4+/-36.6 CFU per plate). Salmonella in preenrichment was concentrated 1.7-fold by IMS and represented 31% of the microbial population captured by the beads, but nonspecific binding was high. As a result of the large numbers of competing bacteria, isolations on both RA and HE agar following IMS were quite difficult (mean value for Salmonella colonies: 79.9+/-42.7 CFU per plate; mean value for non-Salmonella colonies: 144.1+/-75.7 CFU per plate; ratio of Salmonella to non-Salmonella colonies: 0.8). This study indicates that SC broth is superior to IMS in the isolation of Salmonella from raw ground meat.