PubMed Health⌕ Search

Biomedical subjects

L K Ng

Publications and source records attributed to L K Ng.

At least 55 records · Page 3Linked to original sources
PubMed1981

Enterobacteriaceae associated with meats and meat handling.

The source of Enterobacteriaceae on meats was shown to be associated with the meat-handling work surfaces in two packing plants studies. A total of 2,343 Enterobacteriaceae were isolated and identified from meat samples and work surfaces at the packing plants and at the retail facilities. Escherichia coli biotype I and Serratia liquefaciens were detected at all stages of meat handling, indicating that they may be present in meats throughout the meat-handling system. Enterobacter agglomerans and S. liquefaciens were the predominant Enterobacteriaceae at the retail level, but they had limited indicator potential for sanitation and hygiene, Klebsiella pneumoniae was a frequent isolate among Enterobacteriaceae from meats and meat-handling surfaces in the packing plants but not at the retail level, indicating that this organism might signal unhygienic handling of meats at the retail level.

Animals↗
PubMed1980

Estimation of Escherichia coli in raw ground beef.

This study was undertaken to establish and evaluate more rapid methods of estimating Escherichia coli in ground beef than the standard most probable number (MPN) technique. Direct inoculation of and modifications to EC medium gave unreliable estimates of the presumptive E. coli count. Solid media incubated at an elevated temperature were compared to the MPN technique. Anderson and Baird-Parker's tryptone bile agar (TBA) method and prepoured plates of Endo, Levine eosin methylene blue (EMB), and violet red bile (VRBA) agars incubated at 44 degree C gave equivalent counts to the standard MPN method. Anderson and Baird-Parker TBA was the most selective solid medium for E. coli estimation, but all selective media incubated at elevated temperature reduced apparent E. coli counts by as much as 50%. Indole-producing and lactose-fermenting Enterobacteriaceae, capable of growth at elevated temperature, were tested for their growth on TBA, EMB, and VRBA at elevated temperature. TBA was selective for E. coli biotype I compared to other Enterobacteriaceae that predominate in meats. VRBA and EMB incubated at elevated temperature were not as selective as TBA, but differences in colonies could be observed between typical E. coli colonies and other Enterobacteriaceae on these media. Therefore, VRBA incubated at elevated temperature is proposed as a quality assurance screening test for presumptive E. coli in ground meat. Resuscitation techniques and prepoured plates with VRBA increased recovery levels of presumptive E. coli, but, under the conditions of this study, not to levels that represented a significant practical difference.

Animals↗
PubMed1978

Incidence and relationship of group D streptococci with other indicator organisms in meats.

Raw and processed meats were analyzed for presumptive group D streptococci using KF streptococcus agar. Counts were compared with coliform, presumptive Escherichia coli, and Enterobacteriaceae counts but no meaningful relationships were observed. Results indicated that group D streptococci and E. coli type I were principally contaminants from the packing plant, rather than at retail level. The predominating group D streptococcus in both beef and pork cuts was Streptococcus faecalis, while in processed meat (bologna), the predominating group D streptococci were Streptococcus faecium var. durans and Streptococcus faecium. Streptococcus bovis was not detected among the isolates from any meat samples. Marked differences were noted in numbers of group D streptococci in processed meat from different manufacturers. The results did not support the use of group D streptococci as alternative indicator organisms for meats. However, the association of group D streptococci with packing plant contamination may prove to be of value.

Animals↗
PubMed1975

Experimental "auricular electroacupuncture" in morphine-dependent rats: behavioral and biochemical observations.

The experimental paradigm reported here provides a useful animal model with which to further study the effects of regional electrostimulation and its possible relationship with electrical acupuncture. What similarities there may be between electrical acupuncture and the technique of regional electrocerebral stimulation used for production of electrosleep and electronarcosis in animals and man remain to be elucidated. Further research studies, both clinical and basic, are clearly needed to answer some of the questions relating to the safety, efficacy, and possible mechanisms by which a technique such as electrical acupuncture may exert its effects.

Acupuncture Therapy↗
PubMed1975

Modification of morphine-withdrawal syndrome in rats following transauricular electrostimulation: an experimental paradigm for auricular electroacupuncture.

The experimental paradigm reported here provides a useful animal model with which to further study the effects of regional electrostimulation and its possible relationship with electrical acupuncture. What similarities there may be between electrical acupuncture and the technique of regional electrocerebral stimulation used for production of electrosleep and electronarcosis in animals and man (Wageneder et al., 1966) remain to be elucidated. Further research studies, both clinical and basic, are clearly needed to answer some of the questions relating to the safety, efficacy, and possible mechanisms by which a technique such as electrical acupuncture may exert its effects.

Acupuncture Therapy↗
PubMed1973

Delta 9 -tetrahydrocannabinol and ethanol: differential effects on sympathetic activity in differing environmental setting.

Serum dopamine beta-hydroxylase activity, a useful biochemical index of peripheral sympathetic nervous activity, was measured in rats treated with Delta(9)-tetrahydrocannabinol or ethanol or both substances. After 7 days of treatment with either substance, serum dopamine beta-hydroxylase activity decreased significantly. Combined treatment with both agents enhanced the effects of each given alone. In rats subjected to immobilization stress, treatment with Delta(9)- tetrahydrocannabinol appeared to potentiate the stress-induced increase in serum enzyme activity. Treatment with ethanol, with or without Delta(9)-tetrahydrocannabinol, effectively blocked this increase in enzyme activity. These results show that both substances have significant effects on the sympathetic nervous system which are critically influenced by environmental setting.

Alcoholic Intoxication↗