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Biomedical subjects

J B Fox

Publications and source records attributed to J B Fox.

18 recordsLinked to original sources
PubMed1998

Fate of gamma-irradiated Listeria monocytogenes during refrigerated storage on raw or cooked turkey breast meat.

The radiation resistance and ability of Listeria monocytogenes ATCC 7644, 15313, 43256, and 49594 to multiply on irradiated, air-packed, refrigerated raw or cooked turkey breast meat nuggets (ca. 25 g) and ground turkey breast meat was investigated. Gamma-radiation D values for L. monocytogenes were significantly different on raw and cooked nuggets, 0.56 +/- 0.03 kGy and 0.69 +/- 0.03 kGy, respectively; but they were not significantly different (P < or = 0.05) on raw and cooked ground turkey meat. High populations (approximately 10(9) CFU/g) of L. monocytogenes declined during 14 days of storage at 4 degrees C in both irradiated and nonirradiated samples of raw but not of cooked ground turkey breast meat. A moderate inoculum (approximately 10(3) CFU/g) did not survive a radiation dose of 3 kGy. The population increased in cooked but not in raw samples of irradiated ground turkey meat stored at either 2 or 7 degrees C for 21 days. The D value changed significantly from 0.70 +/- 0.04 to 0.60 +/- 0.02 kGy when the product was cooked to an internal temperature of 80 degrees C before irradiation. Growth on either raw or cooked turkey meat did not alter the radiation resistance of L. monocytogenes. Analyses were performed for pH, aw, moisture, and reducing potential of raw and cooked turkey meat and for pH, amino acid profile, thiamine, and riboflavin contents of aqueous extracts of raw and cooked turkey meats without identifying the factor or factors involved in differences in the survival and multiplication of L. monocytogenes on raw and cooked meat.

Animals↗
PubMed1998

Radical oxidation of riboflavin.

Riboflavin, lumiflavin and lumichrome were produced by light catalysis and gamma irradiation. Their formation under various conditions was determined, and a number of intermediates identified. Fluorescence excitation and emission spectra were determined for the compounds and compared with the absorbency spectra. While lumiflavin predominated in alkali and lumichrome in neutral solutions in the light-catalyzed reaction, all products were produced to some extent under all conditions. Gamma radiation resulted only in the formation of lumichrome, with no observable intermediates.

Catalysis↗
PubMed1993

Effect of reductant level in skeletal muscle and liver on the rate of loss of thiamin due to gamma-radiation.

A study was made of thiamin content of the skeletal muscles and livers of pork, chicken and beef after gamma-irradiation. gamma-Radiation from a 137Cs source was used to irradiate the samples with doses of 0, 1.5, 3, 6 and 10 kGy at 2 degrees C. Samples were also titrated with dichlorophenol-indophenol to determine the reducing capacity of the tissues. The rate of loss of thiamin upon irradiation was found to be about three time as as fast in skeletal muscle as it was in liver, and to be a function of the reducing capacity of the tissues, the loss decreasing with increasing reductant titer. For the same amount of thiamin loss, liver could be irradiated to three times the dose as could muscle.

Animals↗
PubMed1989

Effect of gamma irradiation on the B vitamins of pork chops and chicken breasts.

A study was made of the effect of low-dose gamma irradiation on the content of thiamine (B1), riboflavin (B2), niacin, pyridoxine (B6) and cobalamin (B12) in pork chops, and thiamine, riboflavin and niacin in chicken breasts. Gamma irradiation from a caesium-137 source was used to irradiate the samples in a range of 0.49 to 6.65 kGy from -20 to +20 degrees C. Over the range of dose and temperature studied it was possible to derive a mathematical expression for predicting the losses. A calculation was made of the effect of the loss of thiamine, riboflavin and niacin due to irradiation on the overall loss of these vitamins in the American diet. The losses of riboflavin and niacin were of the order of a fraction of a per cent. Pork is an important source of thiamine, but the calculated loss at 1.0 kGy of this vitamin in cooked pork was only 1.5 per cent. There were initial increases with radiation doses up to 2-4 kGy in the measured concentrations of riboflavin and niacin in both pork and chicken. The increases were highly significant, and are of concern both to the study of radiation effects and the chemical method of the determination of these two vitamins.

Animals↗
PubMed1988

A retrospective analysis of air-evacuated hypothermia patients.

This study reviews the outcome of 17 hypothermic patients air evacuated by a civilian helicopter transport service. Age (33 +/- 23), type and duration of exposure, and rewarm methods were examined for each patient. Temperature (T), heart rate (HR), blood pressure (BP), respiratory rate (RR), Glasgow coma score (GCS), trauma score (TS), CRAMS score (CS), and cardiac rhythm in the pre-hospital setting and in the emergency department (ED) were compared to outcome. Eight of the patients had extensive exposure to a cold environment ranging from 4 h to 10 d. The remaining 9 patients were exposed to cold water ranging from 15 min to 4.5 h. By severity of hypothermia as measured in the ED, 6 patients who were hypothermic at the scene were normothermic (t greater than 35 degrees C), 5 patients were classified as mild (t = 35-31.5 degrees C), 3 as moderate (T less than 31.5-25.5 degrees C), and 3 patients were severely hypothermic (T less than 25.5 degrees C). The GCS, TS, and CS were not indicative of outcome. During rewarming, 3 patients had paradoxical temperature drops, and 5 patients had atrial fibrillation. Three patients required cardiopulmonary resuscitation in the field. Two were discharged with resolving disabilities, and 1 expired. No ventricular fibrillation or J waves occurred. All patients were effectively rewarmed without incident. All patient disabilities and the single fatality were not directly related to hypothermia. There were no long-term adverse consequences of helicopter transport in these hypothermic patients.

Adolescent↗
PubMed1986

Paramedic use of advanced life support procedures: experience and attitude survey.

To gather information about paramedic use of 11 advanced life-support (ALS) procedures, 74 emergency physicians and 171 paramedics practicing in Utah were surveyed. Response was 66% and 65%, respectively. Performance difficulty, frequency of use, and success rate were evaluated. The willingness of physicians to order, and paramedics to perform each procedure were compared. Physicians' and paramedics' difficulty ratings were significantly different (P less than .001) for only 3 of the 11 procedures. During the study period, paramedics successfully performed 455 procedures; 229 were performed by 15 (13%) of the responding paramedics. The reported success rate for all attempted procedures was 82% (455/557). The number of attempts and the success rate was significantly higher (P less than .05) for paramedics with secondary medically affiliated employment. Paramedics were significantly more willing to perform 7 of the 11 procedures (P less than .001) than physicians were willing to order. We conclude that paramedic and physician difficulty ratings were generally similar, that many types of ALS procedures are rarely performed, that a small percentage of paramedics perform the largest number of ALS procedures, that secondary employment increases paramedics' procedural attempts and improves success rates, and that they are more willing to perform ALS procedures than physicians are to order them.

Allied Health Personnel↗
PubMed1982

Interaction between sample preparation techniques and three methods of nitrite determination.

Meat samples containing nitrite and varying concentrations of ascorbate, cysteine, and sodium chloride were prepared for nitrite analysis. The methods used were the AOAC method of dilution and heating; the addition of mercuric chloride, charcoal, and Carrez reagents at 2 different pH values; and direct analysis of sample supernatants with no treatment (control). The effect of these initial conditions and preparation methods on measured nitrite was determined by using 3 different Griess reagent combinations and chemiluminescent and differential pulse polarographic techniques. Systematic variations were observed in samples treated with mercuric chloride, while the addition of Carrez reagents had little or no effect. Best results were obtained by the AOAC dilution/heating method under alkaline conditions, or by charcoal addition followed by chemiluminescent or colorimetric nitrite determination. Statistical analysis of the nitrite concentrations determined in the several samples showed that these 3 procedures were precise to about 5-6% CV, which was not significantly different from the CV value of 4% determined from replicate analyses.

Indicators and Reagents↗
PubMed1981

Interaction between sample preparation techniques and colorimetric reagents in nitrite analysis in meat.

The amount of nitrite measured in model and meat systems was a function of the interactions of the chloride and ascorbate concentrations with the method of sample preparation and the combination of Griess reagents used for colorimetric determination. Ascorbate caused loss of nitrite in the samples when heated and interfered in the Griess reaction, increasing the concentration of pigment formed from any given concentration of nitrite if sulfanilic acid and N-(1-naphthyl)-ethylenediamine were used, and decreasing the amount if sulfanilamide and 1-naphthylamine were used. The interference was eliminated by both the AOAC procedure and mercuric chloride addition, although the former were less effective at higher ascorbate concentrations. Chloride increased the amount of pigment formed from a given amount of nitrite with sulfanilic acid but had no effect on the amount of sulfanilamide pigment.

Ascorbic Acid↗
PubMed1978

Comparison of sample preparation procedures for colorimetric analysis of nitrite in frankfurters.

Three groups of methods for analyzing nitrite in meat are compared. All methods consist of a sequence of steps, grouped according to initial extraction procedures. In Group 1, the sample is treated with borate followed by HgCl2 or Carrez I, and then Carrez II. In Group 2, the sample is diluted with water, heated at 80 degrees C, and analyzed immediately (AOAC) or after addition of either Na2CO3 and FeCl3 or HgCl2. In Group 3, the sample is made alkaline with NH4Cl buffer and then treated with one of the following: activated carbon plus Carrez I and II, alumina cream, or AIK(SO4)2. At each step when the method involved the addition of a chemical, supernates and precipitates (if formed) were analyzed for nitrite by Griess reagent both before and after AOAC digestion. The normally discarded precipitates formed after addition of HgCl2 and Carrez I and II contained bound nitrite that could be detected by AOAC analysis. Except in the AOAC method, HgCl2 improved nitrite analysis. Results by AOAC analysis were 3 to 300% higher than those determined after addition of any chemical or combination of chemicals. Spiked meat samples could not be used in comparing nitrite analysis methods because results were misleading. Acid meat samples, such as fermented sausages, required neutralization before AOAC analysis.

Animals↗
PubMed1968

Effect of anaerobiosis on staphylococcal nuclease production.

Five strains of Staphylococcus aureus were examined quantitatively for the production of nuclease under aerobic and anaerobic conditions. Hydrolysis of deoxyribonucleic acid and ribonucleic acid was detected by measuring the release of acidsoluble nucleotides spectrophotometrically. We found that the enzyme was produced anaerobically, as well as aerobically, and that anaerobiosis had no effect on production of this enzyme when other conditions, such as pH, were held constant.

DNA↗
PubMedDate not supplied

Effect of residual ascorbate on determination of nitrite in commercial cured meat products.

Residual ascorbate in cured meat slurries results in different amounts of pigment being produced from different Griess reagent combinations. The phenomenon was used to study residual ascorbate in commercial cured meat products which had a variety of textures, acidities, moisture and meat content, fat, homogeneity, initial nitrite, and processing conditions. Diluting and heating the samples according to the AOAC procedure did not completely eliminate the ascorbate interference, but making the sample alkaline did. Determining nitrite separately in supernate and precipitate from the first dilution showed the effect of heating to be the elimination of interferences and solubilization or extraction of nitrite from the precipitate.

Animals↗
PubMedDate not supplied

Comparison of chemiluminescent and AOAC methods for determining nitrite in commercial cured meat products.

A chemiluminescent detector was used to measure nitrite in a variety of commercial cured meat products, using the AOAC sample preparation procedure, 24.041. A comparison of the NaNO2 values obtained by using sulfanilamide/N-(1-naphthyl)ethylenediamine (SAN/NED) reagent, sulfanilamide/1-naphthylamine reagent, and chemiluminescent detection (CLD) revealed no significant differences between the latter 2 detection methods. The AOAC SAN/NED reagent combination gave an average of 24.6% lower NaNO2 results than CLD. Examination of the sample preparation extraction and heating steps indicated that the procedure could not be made more rapid because of the need to destroy residual reductants and release "bound-complexed-reacted" nitrite from the meat samples.

Animals↗