Clopidogrel compatibility with concomitant cardiac co-medications: a study of its interactions with a beta-blocker and a calcium uptake antagonist.

The safety and pharmacodynamic compatibility of clopidogrel with medications commonly used in patients with atherosclerosis, such as, a beta-adrenergic receptor antagonist (atenolol) and a calcium uptake inhibitor (nifedipine) were assessed. Atenolol and nifedipine interactions with clopidogrel were studied in patients with peripheral arterial obstructive disease taking a well-established regimen of nifedipine (N group of 6 patients) and in patients with coronary artery disease taking a well-established regimen of either atenolol (A group of 8 patients) or of atenolol and nifedipine (AN group of 8 patients). The study was conducted as a double-blind, randomized, crossover comparison of clopidogrel, 75 mg once daily, and placebo treatment for 7 days, with a 14-day washout between treatments. Pharmacodynamic interactions between atenolol and nifedipine, either alone or in combination, and clopidogrel were assessed primarily on the clinical control of angina or hypertension and, secondarily, by comparing the extent of inhibition of ADP (5 microM)-induced platelet aggregation achieved between the 3 groups. The mean number of anginal episodes per patient during the placebo week was 1.50, 9.0 and 11.5 in the A, N and AN groups, respectively; during the week of clopidogrel treatment, it was 1.39, 7.3 and 9.0, respectively, indicating no change in occurrence. Likewise, review of the use of nitrates (long or short acting) did not suggest any major change in usage during any period of the study. ECGs did not change between the three recording times (at screening and at the end of each treatment period). Vital signs were also unchanged throughout. Percent inhibition of platelet aggregation on day 7 was 31% in the N group, 39% in the A group, 28% in the AN group, and 33% overall. In conclusion, the coadministration of clopidogrel did not interfere with the clinical control of hypertension or angina established with atenolol or nifedipine, or both. Clopidogrel retained its full antiplatelet effect, and there were no safety problems caused by the coadministration.

Antimicrobial activity of Leuconostoc gelidum against closely related species and Listeria monocytogenes.

A newly isolated strain of Leuconostoc gelidum was evaluated for its ability to inhibit a wide spectrum of lactic acid bacteria, meat spoilage bacteria and food-related human pathogens, including Listeria monocytogenes. It was inhibitory to most of the lactobacilli, all the leuconostocs, and three strains of L. monocytogenes when tested both by direct and well diffusion methods. Cell-free extract retained activity after 60 min at 100 degrees C but was sensitive to protease. Dialysis suggested a molecular weight in excess of 10(4) daltons. The inhibitory effect was bactericidal and rapid.

The effect of ageing treatment on the microbiology and storage characteristics of beef in modified atmosphere packs containing 25% CO(2) plus 75% O(2).

The influence of different ageing treatments (1 week hung in air; 1 and 3 weeks in vacuum packs) on the microbiological, colour, odour and rancidity characteristics of beef loin steaks during storage at 1° and 6°C in modified atmosphere packs (MA) containing 25% CO(2) + 75% O(2) was determined. Steaks from the 3-week ageing treatment discoloured more rapidly and developed off-odours sooner than those from the 1-week ageing treatments at both storage temperatures. Evidence of rancidity, using the thiobarbituric acid assay, was only observed in the 3-week aged steaks stored at 6°C. The poorer storage stability of the 3-week aged steaks was explained by higher initial levels of bacteria resulting from growth during ageing. Leuconostocs were the dominant bacteria on most MA samples following storage and appeared the main cause of spoilage, although B. thermosphacta and Pseudomonas spp may have contributed to off-odours on samples aged hung and stored at 6°C.

A numerical taxonomic study of non-motile non-fermentative gram-negative bacteria from foods.

A numerical taxonomic study using 155 unit characters was performed on 63 strains of Gram-negative non-motile non-fermentative bacteria isolated from proteinaceous foods. Similar bacteria from other sources and several Pseudomonas strains from meat were included for reference purposes. Three clusters were observed at 76% S which contained all the food strains. Cluster 1 was composed entirely of Acinetobacter strains including 17 isolated from foods that were provisionally identified with Acinetobacter johnsonii. Cluster 2 contained 22 strains identified as Psychrobacter immobilis, of which 20 were from food. Cluster 3 contained all the Pseudomonas reference strains and 26 non-motile strains isolated from meat. These were shown to be non-motile variants of Pseudomonas fragi. A simple identification scheme, based on five tests, is presented for the distinction of the three types of bacteria.

Rapid Estimation of Microbial Numbers on Meat and Poultry by the Direct Epifluorescent Filter Technique.

The direct epifluorescent filter technique (DEFT) for rapid estimation of microbial numbers was evaluated by comparison with the plate count on a variety of uncooked red meat and poultry samples. Good agreement [correlation coefficient (r) = 0.95-0.96] was obtained from samples with plate counts of 5 × 103/g or /cm2 and above from red meat carcasses (surface swabbed), aerobic or vacuum packed chill-stored joints (surface sampled - stomachered) and frozen beef (thawed stomachered). For stored and unstored raw poultry sampled by skin scraping or stomachering of muscle and skin good overall correlation (r = 0.88-0.89) was obtained between the DEFT count and the plate count in the ranges 1.1 × 103 to 1.3 × 107/cm2 (skin scraping) and 1 × 104 to 9.5 × 106/g (muscle and skin) even though the DEFT always overestimated counts on samples on which no growth had occurred (plate count <7×104/cm2 or <1×105/g). However, good linearity between DEFT and plate counts allowed use of the regression equation to obtain a good estimate of the plate count on these samples. The DEFT was unsuitable for application to poultry neck skin sampled by shaking because particulate material interfered with counting. This was also a problem with Mechanically Recovered Meat although the DEFT gave a fair estimate (r = 0.72) of the plate count on certain types (beef and veal) of this product. The DEFT was capable of providing counts within 35 to 45 min and its applicability to the rapid estimation of bacterial numbers in meat and poultry is discussed.

Classification of some lactic acid bacteria from vacuum-packed meats by direct probe mass spectrometry.

The technique of direct probe mass spectrometry (DPMS) has been applied to the classification of 40 strains of lactic acid bacteria from refrigerated vacuum-packed beef, pork, lamb and bacon. Relationships between strains were examined by multi-variate statistical techniques using sets of ions selected for reproducibility and sample discrimination. Five groups were distinguished which corresponded closely to those detected in a previous numerical taxonomic study. Two groups contained all 12 representatives of a cluster of unidentifiable non-aciduric streptobacteria whose sub-division is supported by other taxonomic evidence. All twenty-one strains from a cluster of aciduric streptobacteria provisionally identified with Lactobacillus sake were contained in two further groups. The sub-division of these aciduric strains revealed by DPMS has not been verified by other techniques and requires further investigation. The fifth group contained Leuconostoc strains. The study demonstrates the value of DPMS in confirming and clarifying classification schemes obtained by conventional methods.

A study of the relative incidence of different Pseudomonas groups on meat using a computer-assisted identification technique employing only carbon source tests.

A computer-assisted probabilistic identification technique employing 18 carbon source utilization tests has been developed and applied to 787 Pseudomonas strains isolated from beef, pork and lamb stored under aerobic conditions. Seven hundred and twelve (89.7%) were identified using these tests alone and a further six (0.8%) with extra tests. Taxa detected were Ps. fragi cluster 2, 390 strains (49.6% of all isolates); Ps. fragi cluster 1, 191 strains (24.9%); meat cluster 3, 87 strains (11.1%); Ps. fluorescens biotype I, 31 strains (3.9%); Ps. fluorescens biotype III, 7 strains (0.9%); and Ps. putida, 1 strain (0.1%). The relative incidence of members of the various taxa was similar on beef, pork and lamb, and was unaffected by storage temperature in the range 0 degrees-10 degrees C. Each taxon was also detected at similar rates before and after spoilage. Meat origin (abattoir) affected the frequency of detection of meat cluster 3 and Ps. fluorescens biotype I strains but did not affect the incidence of detection of either cluster of Ps. fragi.

A numerical taxonomic study of lactic acid bacteria from vacuum-packed beef, pork, lamb and bacon.

A numerical taxonomic study using 79 unit characters has been performed on 100 isolates of lactic acid bacteria from refrigerated vacuum-packed beef, pork, lamb and bacon. Three clusters were observed at 78% S which contained all the strains apart from three unidentifiable streptobacteria, one Leuconostoc, and one strain of Pediococcus pentosaceus. One cluster (III) consisted of only one strain of Leuc. paramesenteroides and six unidentifiable Leuconostoc strains. The two largest clusters (I and II) were both composed entirely of streptobacteria. Cluster I contained 31 strains (G + C content 33.2-36.9 moles%) which were not identifiable with any described species. Cluster II contained 57 strains (G + C content 40.7-43.7 moles %) which were provisionally identified with Lactobacillus sake or Lact. bavaricus according to the lactic acid isomer produced. The division of nearly all the streptobacteria into two clearly defined clusters has resolved problems which have existed in the classification of lactic acid bacteria from vacuum-packed meat.

Hot deboning beef with and without electrical stimulation.

Two hot deboning procedures for producing vacuum packed primal beef joints were compared with conventional side chilling followed by cold deboning. Cold shortening toughness was avoided in the hot procedures either by a delay before chilling or by electrical stimulation of the carcass. Overall evaporative losses were 0·6% with hot deboning and 1·9% with cold deboning. Hot deboning reduced drip loss but the effect was smaller after electrical stimulation. The colour of large muscles which cool unevenly on the side was more uniform after hot deboning, but again the improvement was smaller after electrical stimulation. There was no difference in bacterial contamination or growth on hot and cold deboned meat, and instrumental and sensory assessments confirmed that eating quality was similar for all three treatments.