Development and Validation of a UPLC-MS/MS Method to Monitor Cephapirin Excretion in Dairy Cows following Intramammary Infusion

Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 µg kg⁻¹ and 0.96 µg L⁻¹ for feces and urine, respectively. This robust method recovered >60% and >80% cephapirin from spiked blank fecal and urine samples, respectively, with acceptable intra- and inter-day variation (<10%). Using this method, we detected trace amounts (µg kg⁻¹) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 µg L⁻¹). Cephapirin was primarily excreted via urine and its urinary excretion was influenced by day (P = 0.03). Peak excretion (2.69 mg) was on day 1 following intramammary infusion and decreased sharply thereafter (0.19, 0.19, 0.08, and 0.17 mg on day 2, 3, 4, and 5, respectively) reflecting a quadratic pattern of excretion (Quadratic: P = 0.03). The described method for quantification of cephapirin in bovine feces and urine is sensitive, accurate, and robust and allowed to monitor the pattern of cephapirin excretion in dairy cows. This data will help develop manure segregation and treatment methods to minimize the risk of antibiotic loading to the environment from dairy farms.     

Promoting Smoke-Free Homes: A Novel Behavioral Intervention Using Real-Time Audio-Visual Feedback on Airborne Particle Levels

Interventions are needed to protect the health of children who live with smokers. We pilot-tested a real-time intervention for promoting behavior change in homes that reduces second hand tobacco smoke (SHS) levels. The intervention uses a monitor and feedback system to provide immediate auditory and visual signals triggered at defined thresholds of fine particle concentration. Dynamic graphs of real-time particle levels are also shown on a computer screen. We experimentally evaluated the system, field-tested it in homes with smokers, and conducted focus groups to obtain general opinions. Laboratory tests of the monitor demonstrated SHS sensitivity, stability, precision equivalent to at least 1 µg/m³, and low noise. A linear relationship (R² = 0.98) was observed between the monitor and average SHS mass concentrations up to 150 µg/m³. Focus groups and interviews with intervention participants showed in-home use to be acceptable and feasible. The intervention was evaluated in 3 homes with combined baseline and intervention periods lasting 9 to 15 full days. Two families modified their behavior by opening windows or doors, smoking outdoors, or smoking less. We observed evidence of lower SHS levels in these homes. The remaining household voiced reluctance to changing their smoking activity and did not exhibit lower SHS levels in main smoking areas or clear behavior change; however, family members expressed receptivity to smoking outdoors. This study established the feasibility of the real-time intervention, laying the groundwork for controlled trials with larger sample sizes. Visual and auditory cues may prompt family members to take immediate action to reduce SHS levels. Dynamic graphs of SHS levels may help families make decisions about specific mitigation approaches.     

Differentials of fertility between polygynous and monogamous marriages in rural Bangladesh

This paper discusses polygynous marriages in rural Bangladesh, using marital status and birth registration data from the Demographic Surveillance System (DSS) of the International Center for Diarrheal Disease Research, for the period 1975-79. Of all the marriages recorded during this period about 5% were polygynous. To identify the women polygynously married, 1974 census data of the DSS area were used. The difference in age at marriage between the polygynous groom and his subsequent wife was 15 years on average. The socioeconomic indicators studied were education, occupation and area of dwelling space. In general, these indicators between women in monogamous marriages were significantly higher than between the women in polygynous unions. During the period 1976-79, 863 polygynous marriages were recorded (4.9% of all marriages in the study area). Polygynous marriages were found to be less frequent among men with 2ndary and higher levels of education. The highest proportion of polygynous marriages occurred among husbands with no schooling or Koranic education. The general fertility rate of women in monogamous marriages was significantly higher than for women in polygynous marriages, overall and in all age groups except 20-24. During the period 1975-79, the mean number of liveborn children for monogamous women was higher than that of polygynous women.     

A mass spectrometric technique for detecting and identifying by-products in the synthesis of peptides

The utility of a new mass spectrometric technique for detecting and identifying peptide by-products produced in the synthesis of peptides is demonstrated. The technique involves three sequential steps: (1) practically nondestructive 252Cf plasma desorption mass spectrometric analysis of monolayer amounts of the peptide(s) of interest bound to a thin layer of nitrocellulose; (2) enzyme-catalyzed microscale chemical reaction of the surface-bound peptide(s) to produce structurally informative hydrolysis products; (3) plasma desorption mass spectrometric analysis of these hydrolysis products. The first step determines the presence and the molecular weights of unwanted by-products resulting from errors or incomplete reactions during synthesis. The subsequent two steps provide information on the precise location in the peptides where errors have occurred. In the present paper, the technique is applied to an investigation of unwanted peptide by-products associated with the use of tryptophan during stepwise solid-phase peptide synthesis. Synthetic preparations of melittin and [Bpa-8]dynorphin A (1-17) were each found to contain a major impurity with molecular weight 28 Da higher than that of the desired product. The impurity in the melittin preparation, in which the final deprotection step involved the high-low HF procedure, was shown to result from incomplete removal of the formyl group from Trp-19. On the other hand, the impurity in the [Bpa-8]dynorphin A (1-17) preparation, where the removal of the formyl group from Trp-14 was carried out using piperidine, was shown to result from migration of the formyl group to Lys-11 or Lys-13.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bacterial cellulases and saccharification of lignocellulosic materials

Five locally isolated bacterial strains produced extracellular cellulase enzymes, primarily CMCase, when grown on different natural and commercial cellulosic substrates. Extracellular CMCase and avicelase activity was higher with the strain CLS-32, a Cytophaga sp., compared to four other strains. The whole-cell preparations of these isolates were found to saccharify cellulosic substrates to reducing sugars. Maximum release of reducing sugar (5.75 mg ml⁻¹) was obtained with CLS-32 using sugar cane bagasse as growth and hydrolysis substrates.     

Organogenesis and plant formation from cotyledon explant cultures of wild turnip rape (Brassica tournefortii L.)

Cotyledon explants of Brassica tournefortii L. were excised from germinated seedlings and cultured on Murashige & Skoog's [6] basal medium supplemented with various combinations of cytokinins and auxins, Both cytokinin and auxin were required for induction of shoot organogenesis. Of the three cytokinins tested (in combination with a low concentration of IAA), kinetin was found to be the best for shoot regeneration. On this medium, cotyledonary explants invariably underwent callusing followed by multiple shoot formation. NAA in combination with any of the three cytokinins yielded a reduced number of shoots or none, but favoured good callus growth. Callus so produced also regenerated shoots when subcultured on media containing high concentration of KIN or ZEA and low concentration of IAA. Shoots were rooted during prolonged incubation on the same medium or on MS medium free of growth regulators. Mature plants were grown in the greenhouse.     

Luteolytic action of two antiprogestational agents (RU-38486 and ZK-98734) in the rat

RU-38486 or ZK-98734 treatment (3 mg/day, s.c.) to intact or hysterectomized adult female rats on Days 5-7 post coitum induced changes characteristic of luteolysis. Ultrastructurally, the luteal cells exhibited an extensive vacuolization of the cytoplasm and perinuclear areas, degeneration of mitochondrial cristae, massive accumulation of lipid droplets, increase in number of lysosome like granules and heterochromatinization of the nucleus. In general, RU-38486 induced more marked degeneration of the luteal cells than did ZK-98734. There was also a significant decrease in peripheral plasma progesterone concentrations in treated rats. We suggest that these antiprogestagens act via inhibition of luteal function in addition to their antagonism at the uterine progesterone receptor level.