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Background: In human immunodeficiency virus (HIV) treatment, tenofovir alafenamide (TAF) is associated with greater increases in all fasting cholesterol subgroups compared with tenofovir disoproxil fumarate (TDF). Because lipid abnormalities may contribute to cardiovascular morbidity and mortality, cardiovascular risk assessment is integral to routine HIV care. This post hoc study evaluates the impact of lipid changes on predicted atherosclerotic cardiovascular disease (ASCVD) risk and statin eligibility in treatment-naive adults living with HIV treated with TAF or TDF., Methods: Participants (N = 1744) were randomized (1:1) to initiate TAF or TDF, each coformulated with elvitegravir/cobicistat/emtricitabine (studies GS-US-292-0104 and GS-US-292-0111). Eligibility for statin therapy and estimated 10-year ASCVD risk among adults aged 40-79 years treated with TAF or TDF for 96 weeks (W96) were analyzed based on American College of Cardiology/American Heart Association Pooled Cohort Equations. Categorical shifts in 10-year ASCVD risk from <7.5% to ≥7.5% by W96 on TAF versus TDF were calculated., Results: Participants initiating TAF versus TDF in the overall study population showed small but significant increases in median fasting lipid parameters at W96, including total cholesterol (191 vs 177 mg/dL; P < .001), low-density lipoprotein ([LDL] 119 vs 112 mg/dL; P < .001), and high-density lipoprotein ([HDL] 51 vs 48 mg/dL; P < .001), respectively. At baseline, 18% and 23% on TAF versus TDF had a 10-year ASCVD risk score ≥7.5%, with mean risk scores low overall for TAF versus TDF at baseline (4.9% vs 5.4%; P = .35) and W96 (6.1% vs 6.2%; P = .04). Increases in ASCVD risk from baseline to W96 were driven by both increasing age and changes in total cholesterol (TC) and HDL cholesterol. At W96, TC/HDL ratios (median) were 3.7 for both groups ( P = .69). There was no difference between shifts in categorical risk for TAF versus TDF (9% vs 5%; P = .19). Eligibility for high-intensity statin therapy were similar for TAF versus TDF groups (19% vs 21%; P = .47)., Conclusions: Lipid changes with TAF as part of coformulated regimens do not substantively affect CVD risk profiles compared with TDF., (© The Author(s) 2019. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Transmission infrared analysis, which has been successfully applied to milk analysis, was assessed for the quantitative analysis of fat and protein in meat products. Meats of varying fat and protein content were converted into milk-like emulsions, which were, in turn, analyzed by standard chemical methods and by a Multispec M infrared analyzer. The performance of the instrument for meat analysis using a standard milk calibration was also assessed and compared with the instrument set with a meat calibration. Both approaches provided a good estimate of the fat and protein content for a range of meat products, the meat calibration being more accurate than the milk calibration. The infrared method allowed for rapid and accurate analysis of meat and has future potential in the meat industry for quality control purposes., (Copyright © 1984. Published by Elsevier Ltd.)

The Mojonnier method was compared with the conventional Soxhlet method for the determination of fat in 7 different meat products to assess its use as a standard reference method for calibration of commercial quantitative infrared transmission analyzers (e.g., Multispec M, Milkoscan 300 or 104). Results for the meat samples obtained by the Mojonnier method did not differ significantly from those obtained by the Soxhlet method. In addition, the Mojonnier method was less time-consuming and more precise than the Soxhlet; therefore, it can be used as a standard reference procedure for the calibration and assessment of infrared milk analyzers in their potential application to the rapid determination of fat in meat and meat products.

The effect of switching individual cow Record of Performance milk samples from on-farm Babcock analytical system to centralized infrared analysis was investigated. The effects of lipolytic activity on the signals of the fat (5.73/5.58 and 3.48/3.56 microns) and protein (6.46/6.68 microns) wavelengths of filter instruments showed that lipolysis decreased the infrared fat signal and concurrently increased the protein signal. The chain length (3.48/3.56 microns) signal was unaffected by lipolysis due to the concordant movement of the reference wavelength baseline with the changes in the sample wavelength signal. Storage trials (3 d) of preserved milk samples indicated no direct relation between fat signal depression and chemically determined free fatty acid levels. Microbial growth and agitation also contributed to changes observed in samples studied under controlled conditions. Based on concurrent infrared, Babcock, and Mojonnier analyses of approximately 900 samples on d 1 and 3, there was a consistent but marginal drop in the carbonyl (5.73/5.56 microns) fat signal and an increase in the amide (6.46/6.68 microns) protein signal, but these changes were of limited significance. A study of 3-d and older samples indicated that significant levels of acid were produced, indicative of microbial growth. A comparison of Babcock results carried out on-farm, Mojonnier analyses in the laboratory, and their corresponding infrared results did not show statistically significant differences. Other than the inherent variability present in the individual cow samples, there were minor quality changes occurring under the present sample handling system due to a combination of lipolysis, microbial growth, and acid production. Refrigeration of Record of Performance samples during transport and at the central laboratory is recommended to minimize these changes.

An investigation was undertaken to determine whether ammonium ion could be quantitated in aqueous solution by using commercially available infrared filter instruments such as the Multispec M1 analyzer. Ammonium salt solutions were scanned using an infrared spectrophotometer modified specifically to facilitate the study of aqueous systems and were shown to have 2 main absorption bands at 3.49 microns (2865 cm-1) and 6.89 microns (1451 cm-1). The 3.49 microns band did not correspond to any individual band noted in the literature and was concluded to be a composite of fundamental bands and Fermi resonances due to hydrogen bonding affecting the ion in solution. The response of the 6.89 microns band to NH4+ concentration was approximately twice that of the 3.49 microns band, and quantitation of the ammonium ion was assessed by the dual wavelength method as employed in filter-based commercial infrared analyzers. Good quantitation was obtained using 5.56 microns as a reference wavelength, and the slope of the standard curve of ammonium sulfate was not significantly affected by pH in the pH 3-8 region. A 6.86 microns sample filter and a 5.56 microns reference filter were installed in a Multispec M1 analyzer and a linear response was obtained for concentrations of up to 0.6% ammonium sulfate. Accurately weighed samples of ammonium sulfate were converted to ammonia by using the micro-Kjeldahl procedure and then distilled into standard acid, diluted to volume, and assessed by titration and transmission infrared analysis. The infrared method was more accurate than the titration method in replicating the initial weights.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of infrared absorption by the use of a CH stretch filter which isolates wavelengths in the order of 3.4-3.5 microns has been suggested as a replacement for the conventional carbonyl stretch absorption measurement or as an additional measurement for the estimation of fat in aqueous fat emulsions. To determine the merits of this CH stretch measurement, a study was conducted with a series of natural fats selected for their differences in average molecular weight, fatty acid composition, and degree of unsaturation. In this study, the use of the CH stretch filter, the C = O stretch filter, or the combination thereof could predict the fat content with equal accuracy if the fat was consistent in average molecular weight and degree of unsaturation. For a fat which varied in its degree of unsaturation, the CH filter measurement could be used in conjunction with the iodine value to produce accurate results. The combination C = O filter, CH filter, and the iodine value produced the most accurate results when the intent was to analyze a variety of fats on a single calibration.