Analysis of N-nitrosamines and N-nitrosatable substances from baby bottle rubber teats by liquid chromatography tandem mass spectrometry.

A simple and sensitive method based on liquid chromatography-atmospheric pressure chemical ionisation-tandem mass spectrometry (LC-APCI-MS/MS) was developed and validated to determine the levels of 13N-nitrosamines and N-nitrosatable substances migrated from rubber teats into artificial saliva. The migration test from rubber teats was conducted at 40 °C and for 24 h in artificial saliva, and the migrated artificial saliva solution was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) without further extracting steps. The sensitivity of N-nitrosamines was examined by applying atmospheric chemical ionisation and electrospray ionisation to optimise the mass spectrometric conditions, and the atmospheric chemical ionisation (APCI) mode exhibited 1.6-19 times higher sensitivity. Method validation showed acceptable linearity, precision, and accuracy, and the detection and quantification limits were 0.07-0.35 and 0.24-1.1 µg kg-1, respectively. The developed liquid chromatography-atmospheric chemical ionisation-tandem mass spectrometry method was applied to 39 domestic and imported rubber teats. From 39 samples, N-nitrosamines [N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR), and N-nitroso n-methyl N-phenylamine (NMPhA)] were detected in 30 samples, with N-nitrosatable substances in 17 samples give rise to NDMA, NMOR, and N-nitrosodiethylamine. However, the levels were below the specific migration limit of Korean Standards and Specifications for Food Containers, Utensils, and Packages and EC Directive 93/11/EEC.

Comprehensive Assessment of Acute Isolated or Prominent Dysarthria in the Emergency Department: A Neuro-Emergency Expert's Experience beyond Stroke.

We investigated the clinical characteristics, neuroimaging findings, and final diagnosis of patients with acute isolated or prominent dysarthria who visited the emergency department (ED) between 1 January 2020 and 31 December 2021. Of 2028 patients aged ≥ 18 years with neurologic symptoms treated by a neuro-emergency expert, 75 with acute isolated or predominant dysarthria within 1 week were enrolled. Patients were categorized as having isolated dysarthria (n = 28, 37.3%) and prominent dysarthria (n = 47, 62.7%). The causes of stroke were acute ischemic stroke (AIS) (n = 37, 49.3%), transient ischemic attack (TIA) (n = 14, 18.7%), intracerebral hemorrhage (n = 1, 1.3%), and non-stroke causes (n = 23, 30.7%). The most common additional symptoms were gait disturbance or imbalance (n = 8, 15.4%) and dizziness (n = 3, 13.0%) in the stroke and non-stroke groups, respectively. The isolated dysarthria group had a higher rate of TIA (n = 7, 38.9%), single and small lesions (n = 10, 83.3%), and small-vessel occlusion in Trial of Org 101072 in acute stroke treatment (n = 8, 66.7%). Acute isolated or prominent dysarthria in the ED mostly presented as clinical symptoms of AIS, but other non-stroke and medical causes were not uncommon. In acute dysarthria with ischemic stroke, multiple territorial and small and single lesions are considered a cause.

Peripheral ERK modulates acupuncture-induced brain neural activity and its functional connectivity.

Acupuncture has been widely used as a therapeutic intervention, and the brain network plays a crucial role in its neural mechanism. This study aimed to investigate the acupuncture mechanism from peripheral to central by identifying how the peripheral molecular signals induced by acupuncture affect the brain neural responses and its functional connectivity. We confirmed that peripheral ERK activation by acupuncture plays a role in initiating acupuncture-induced peripheral proteomic changes in mice. The brain neural activities in the neocortex, hippocampus, thalamus, hypothalamus, periaqueductal grey, and nucleus of the solitary tract (Sol) were significantly changed after acupuncture, and these were altered by peripheral MEK/MAPK inhibition. The arcuate nucleus and lateral hypothalamus were the most affected by acupuncture and peripheral MEK/MAPK inhibition. The hypothalamic area was the most contributing brain region in contrast task PLS analysis. Acupuncture provoked extensive changes in brain functional connectivity, and the posterior hypothalamus showed the highest betweenness centrality after acupuncture. After brain hub identification, the Sol and cingulate cortex were selected as hub regions that reflect both degree and betweenness centrality after acupuncture. These results suggest that acupuncture activates brain functional connectivity and that peripheral ERK induced by acupuncture plays a role in initiating brain neural activation and its functional connectivity.

Exploring spatial patterns of acupoint indications from clinical data: A STROBE-compliant article.

Every acupoint has specific indications for acupuncture treatment. These indications, primarily established based on the meridian system, have spatial patterns of symptoms on the human body. We investigated the associations between acupoints and symptom locations in 75 patients with chronic pain who were asked to sketch the localization of their symptoms on body schemes using the bodily sensation map (BSM) system. Combining the BSM and clinical information, we estimated the statistical parameters of relationships between acupoints and spatial information on symptoms. We further visualized spatial patterns of indications of the representative acupoints on the human body template using a Z score. Using a statistical parametric map method, we observed significant activation patterns of 12 acupoint indications with spatial patterns. The 1st group of patterns was distant from the acupoint locus and was strongly associated with the route of the corresponding meridian. The 2nd group was found around the acupoint locus, the majority of which was located at the trunk or back areas. Intensive investigations of the spatial patterns of acupoint indications would be a novel paradigm to explain point specificity of acupuncture treatment based on the original concept of the meridian system. Future studies should include more meaningful clinical data with larger sample sizes.

Various Enterotoxin and Other Virulence Factor Genes Widespread Among Bacillus cereus and Bacillus thuringiensis Strains.

Many strains of Bacillus cereus cause gastrointestinal diseases, and the closely related insect pathogen Bacillus thuringiensis has also been involved in outbreaks of diarrhea. The diarrheal diseases are attributed to enterotoxins. Sixteen reference strains of B. cereus and nine commercial and 12 reference strains of B. thuringiensis were screened by PCR for the presence of 10 enterotoxigenic genes (hblA, hblC, hblD, nheA, nheB, nheC, cytK, bceT, entFM, and entS), one emetogenic gene (ces), seven hemolytic genes (hlyA, hlyII, hlyIII, plcA, cerA, cerB, and cerO), and a pleiotropic transcriptional activator gene (plcR). These genes encode various enterotoxins and other virulence factors thought to play a role in infections of mammals. Amplicons were successfully generated from the strains of B. cereus and B. thuringiensis for each of these sequences, except the ces gene. Intriguingly, the majority of these B. cereus enterotoxin genes and other virulence factor genes appeared to be widespread among B. thuringiensis strains as well as B. cereus strains.

Preparation of Novel Pyridine-Based Aromatic Polyimides and Effect of Fluorine Functionality.

Novel pyridine-containing linear and branched polyimides (Li-PIs and Br-PIs) were prepared by aromatic diamine and triamine monomers. The fluorinated, non-fluorinated and trifunctional pyridine-based monomers, 4-(4-(trifluoromethylphenyl))-2,6-bis(4-aminophenyl)pyridine (FDAPP), 4-phenyl-2,6-bis(4-aminophenyl)pyridine (DAPP) and 4,4',4"-(pyridine-2,4,6-triyl)tribenzenamine (TAPP) amino compounds were synthesized by a modified Chichibabin reaction of different benzaldehydes and p-nitroacetophenone, followed by a reduction of the resulting nitro compounds with hydrazine monohydrate. Functional amine monomers were used to synthesize a series of pyridine-containing linear and branched polyimides, by polycondensation with aromatic dianhydride in N-Methyl-2-pyrrolidone (NMP) via the conventional two-step method. The obtained novel polyimides (PIs) exhibited good solubility in common organic solvents, such as m-Cresol, NMP, DMF, DMSO and DMAc. Moreover, obtained PI films were flexible and showed excellent thermal stability, with the glass transition temperature (T(g)) of 264-331 degrees C and the temperature at 10% weight loss of 580-620 degrees C in a nitrogen atmosphere. The protonated polymer showed UV-vis absorption in the region of 200-400 nm, good optical transparency with the cut-off wave lengths of 372-392 nm, as well as a low dielectric constant (ε) in the range of 3.897-4.276 at 1 MHz. Moreover, the resulted PIs derived from DAPP, FDAPP and TAPP were compared on the basis of fluorine functionality with non-fluorinated parallels, and the effect of branching units was compared with linear polymers.

Synthesis and Characterization of Imidazolium Linear Bisphenol Polycarbonate Hydroxides for Anion Exchange Membrane.

A novel anion exchange membrane of imidazolium functionalized bisphenol polycarbonate was prepared for application in alkaline fuel cell. Di-imidazolium polycarbonate anionic membrane was synthesized by sequential interfacial polymerization, chloromethylation, substitution with 1-methylimidazole and ion exchange with 1.0 M KOH. Chloromethylation reaction was quantitative to achieve a high content of hydroxide ions. Introduction of conjugated imidazole ring in polymer plays an important role to improve both thermal and chemical stability. Bisphenol polycarbonate is a flexible polymer and shows a good solubility in polar organic solvent. The alkaline imidazolium bisphenol polycarbonate rendered an elevated molecular weight with excellent solubility in polar aprotic solvent. Different levels of substitution and ion exchange were investigated; the resulting membranes showed high ion exchange capacities (IECs) of up to 2.15 mmol g(-1). The imidazolium-functionalized copolymer membranes showed lower water affinity (14.2-42.8% at 30 degrees C) that satisfied an essential criterion for fuel cell application. The chemical structure of the imidazolium functionalized polycarbonate membrane was confirmed by 1H NMR spectroscopy, and also the membrane properties were evaluated by thermogravimetric analysis (TGA) and water uptake (WU), IEC and conductivity assessment. They exhibited hydroxide conductivity above 10(-2) S cm(-1) at room temperature and good chemical stability for up to five days without significant losses of ion conductivity.

Synthesis and characterization of sulfonated poly(ether sulfone)s containing mesonaphthobifluorene for polymer electrolyte membrane fuel cell.

The novel sulfonated poly(ether sulfone)s containing mesonaphthobifluorene (MNF) moiety were synthesized and characterized their properties. The prepared polymers have highly conjugated aromatic structure due to the MNF group which is an allotrope of carbon and one atom thick planar sheets of sp2-bonded carbon atoms. Poly(ether sulfone)s bearing tetraphenylethylene on polymer backbone were synthesized by polycondensation and followed intra-cyclization from tetraphenylethylene to form MNF by Friedel-craft reaction with Lewis acid (FeCl3). The sulfonation was performed selectively on MNF units with conc. sulfuric acid. The structural properties of the sulfonated polymers were investigated by 1H-NMR spectroscopy. The membranes were studied by ion exchange capacity (IEC), water uptake, and proton conductivity. The synthesized polymer electrolyte membranes showed better thermal and dimensional stabilities owing to the inducted highly conjugated aromatic structure in the polymer backbone. The water uptake of the synthesized membranes ranged from 23-52%, compared with 32.13% for Nafion 211 at 80 degrees C. The synthesized membranes exhibited proton conductivities (80 degrees C, RH 90%) of 74.6-100.4 mS/cm, compared with 102.7 mS/cm for Nafion 211.

Effects of Temperature and Packaging on the Growth Kinetics of Clostridium perfringens in Ready-to-eat Jokbal (Pig's Trotters).

Ready-to-eat (RTE) Jokbal (Pig's trotter), which consists of pig's feet cooked in soy sauce and various spices, is a very popular and widely sold in Korean retail markets. Commercially, the anaerobically packed Jokbal have also become a popular RTE food in several convenience stores. This study evaluates the effects of storage temperature and packaging methods for the growth of C. perfringens in Jokbal. Growth kinetic parameters of C. perfringens in aerobically and anaerobically packed Jokbals are determined at each temperature by the modified Gompertz equation. The lag time, specific growth rate, and maximum population density of C. perfringens are being analyzed as a function of temperature and packaging method. The minimum growth temperature of C. perfringens in aerobically and anaerobically packed Jokbal is 24℃ and 18℃, respectively. The C. perfringens in Jokbal did not grow under conditions of over 50℃ regardless of the packaging methods, indicating that the holding temperature of Jokbal in markets must be maintained at above 50℃ or below 18℃. Growth of C. perfringens in anaerobically packed Jokbal is faster than in aerobically packed Jokbal when stored under the same conditions. This indicates that there are a higher risks associated with C. perfringens for anaerobically packed meat products.

Network analysis of acupuncture points used in the treatment of low back pain.

Background. The appropriate selection of acupoints is fundamental to obtain a therapeutic effect from clinical acupuncture. Objective. Using a network analysis method, we investigated the acupoints that are combined to treat low back pain (LBP). Methods. To analyze the patterns of the combinations of acupoints, we used acupoint information from clinical trials to calculate the modified mutual information (MI) value, integrated these data, and visualized the network. Results. Based on the highest MI values, we found two different types of acupoint pairs used in the treatment of LBP: pairs of distant acupoints and pairs of local acupoints. Using modular analysis, we found that three acupoint modules were applied in the treatment of LBP: local acupoints, distant acupoints along the meridian, and distant acupoints based on the symptom differentiations. Conclusion. Using the modified MI technique, we provide a systematic framework for the acupoint combination network, and reveal how the technique of acupoint combination is used in the treatment of LBP. Application of this knowledge in acupuncture research may help clarify the mechanisms underlying acupuncture treatment at the systems level, bridging the gap between traditional medicine and modern science.

An amplification of feedback from facial muscles strengthened sympathetic activations to emotional facial cues.

The facial feedback hypothesis suggests that feedback from cutaneous and muscular afferents influences our emotions during the control of facial expressions. Enhancing facial expressiveness produces an increase in autonomic arousal and self-reported emotional experience, whereas limiting facial expression attenuates these responses. The present study investigated differences in autonomic responses during imitated versus observed facial expressions. Thus, we obtained the facial electromyogram (EMG) of the corrugator muscle, and measured the skin conductance response (SCR) and pupil size (PS) of participants while they were either imitating or simply observing emotional expressions of anger. We found that participants produced significantly greater responses across all three measures (EMG, SCR, and PS) during active imitation than during passive observation. These results show that amplified feedback from facial muscles during imitation strengthens sympathetic activation in response to negative emotional cues. Our findings suggest that manipulations of muscular feedback could be used to modulate the bodily expression of emotion, including autonomic responses to the emotional cues.

Visualization of the Meridian System Based on Biomedical Information about Acupuncture Treatment.

The origin of the concept of the meridian system is closely connected with the treatment effects of acupuncture, and it serves as an empirical reference system in the clinical setting. Understanding the meridian channels would be a first step in enhancing the clinical efficacy of acupuncture treatment. To understand the relationship between the location of the disease and the sites of relevant acupoints, we investigated acupuncture treatment regimens for low-back pain in 37 clinical studies. We found that the most frequently used acupoints in the treatment of low-back pain were BL23 (51%), BL25 (43%), BL24 (32%), BL40 (32%), BL60 (32%), GB30 (32%), BL26 (28%), BL32 (28%), and GB34 (21%). For the example of low-back pain, we visualized the biomedical information (frequency rates) about acupuncture treatment on the meridians of a three-dimensional (3D) model of the human body. We found that both local and distal acupoints were used to treat low-back pain in clinical trials based on the meridian theory. We suggest a new model for the visualization of a data-driven 3D meridian system of biomedical information about the meridians and acupoints. These findings may be helpful in understanding the meridian system and revealing the effectiveness of acupuncture treatment.

Fear of acupuncture enhances sympathetic activation to acupuncture stimulation.

BACKGROUND: Acupuncture treatment frequently evokes both pain and fear, causing patients to be hesitant about undergoing the procedure. This study investigated individual differences in autonomic response to acupuncture stimulation and its relationship to fear of the procedure. METHODS: Twenty-seven participants filled out the acupuncture fear scale (AFS) questionnaire and underwent acupuncture stimulation at the LI4 acupuncture point. Autonomic responses were measured by recording the skin conductance response (SCR) throughout acupuncture stimulation. Pearson correlation analysis was performed between the self-reported AFS scores and changes in SCR. RESULTS: After acupuncture stimulation, SCR significantly increased and there were greater individual differences in enhanced sympathetic activations to acupuncture stimulation. Changes in SCR correlated with scores for the painful sensation domain of the AFS. CONCLUSIONS: Our results indicate that fear of acupuncture-induced pain is associated with physiological arousal when people receive acupuncture stimulation. Fear of pain is the dominant factor in acupuncture-related fear and it should be considered in practice and in research.

Modifying Bodily Self-Awareness during Acupuncture Needle Stimulation Using the Rubber Hand Illusion.

Background. The rubber hand illusion (RHI) is an experimental paradigm that manipulates important aspects of body self-awareness. Objectives. We were interested in whether modifying bodily self-awareness by manipulation of body ownership and visual expectations using the RHI would change the subjective perception of pain as well as the autonomic response to acupuncture needle stimulation. Methods. Acupuncture needle stimulation was applied to the real hand during the RHI with (experiment 1) or without (experiment 2) visual expectation while measuring concurrent autonomic changes such as the skin conductance response (SCR). Subjective responses such as perception of the RHI and perceived pain were measured by questionnaires. Results. In experiment 1, the amplitude of the increase in SCR was visibly higher during the synchronous session compared with that of the asynchronous session. In experiment 2, the amplitude of the increase of SCR was lower for the synchronous session compared with that for the asynchronous session. Comparing these two experiments, the visual expectation of needle stimulation produced a greater autonomic response to acupuncture stimulation. Conclusions. Our findings suggest that the sympathetic response to acupuncture needle stimulation is primarily influenced by visual expectation rather than by modifications of body ownership.

Inserting needles into the body: a meta-analysis of brain activity associated with acupuncture needle stimulation.

UNLABELLED: Acupuncture is a therapeutic treatment that is defined as the insertion of needles into the body at specific points (ie, acupoints). Advances in functional neuroimaging have made it possible to study brain responses to acupuncture; however, previous studies have mainly concentrated on acupoint specificity. We wanted to focus on the functional brain responses that occur because of needle insertion into the body. An activation likelihood estimation meta-analysis was carried out to investigate common characteristics of brain responses to acupuncture needle stimulation compared to tactile stimulation. A total of 28 functional magnetic resonance imaging studies, which consisted of 51 acupuncture and 10 tactile stimulation experiments, were selected for the meta-analysis. Following acupuncture needle stimulation, activation in the sensorimotor cortical network, including the insula, thalamus, anterior cingulate cortex, and primary and secondary somatosensory cortices, and deactivation in the limbic-paralimbic neocortical network, including the medial prefrontal cortex, caudate, amygdala, posterior cingulate cortex, and parahippocampus, were detected and assessed. Following control tactile stimulation, weaker patterns of brain responses were detected in areas similar to those stated above. The activation and deactivation patterns following acupuncture stimulation suggest that the hemodynamic responses in the brain simultaneously reflect the sensory, cognitive, and affective dimensions of pain. PERSPECTIVE: This article facilitates a better understanding of acupuncture needle stimulation and its effects on specific activity changes in different brain regions as well as its relationship to the multiple dimensions of pain. Future studies can build on this meta-analysis and will help to elucidate the clinically relevant therapeutic effects of acupuncture.

Do not judge according to appearance: patients' preference of a doctor's face does not influence their assessment of the patient-doctor relationship.

OBJECTIVES: The aim of this study was to investigate whether a patient's preference for a doctor's face is associated with better assessments of relational empathy in the patient-doctor relationship after the first clinical consultation. METHODS: A total of 110 patients enrolled in a traditional Korean medical clinic participated in the study. Patients' preference for doctors' faces was assessed by a two alternative forced choice (2AFC) task, with 60 different pairs of six different Asian male doctors' faces. One of the six doctors then carried out the initial clinical consultation for these patients. The patient-doctor relationship was assessed using the Consultation and Relational Empathy (CARE) measure. RESULTS: The data of all patients' simulated preferences for a doctor's face and their assessment values of a doctor's relational empathy was compared, and no significant correlation was found between both values (r=-0.024, p>0.809). CONCLUSIONS: These findings suggest that the perceived empathy in the patient-doctor relationship is not influenced by the patient's preference for a certain doctor's face. The first impression of a doctor is often determined by his appearance and look. However, whether or not the patient particularly prefers a doctor's face does not seem to matter in developing a good patient-doctor relationship.

Detection and identification of Vibrio species using whole-cell protein pattern analysis.

Outbreaks of foodborne diseases associated with Vibrio species such as V. parahaemolyticus, V. vulnificus, and V. cholerae frequently occur in countries having a dietary habit of raw seafood consumption. For rapid identification of different Vibrio species involved in foodborne diseases, whole-cell protein pattern analysis for 13 type strains of 12 Vibrio species was performed using SDS-PAGE analysis. Pathogenic Vibrio species such as V. parahaemolyticus, V. vulnificus, V. cholerae, V. alginolyticus, V. fluvialis, and V. mimicus were included in the 12 Vibrio species used in this study. Each of the 12 Vibrio species showed clearly specific band patterns of its own. Two different strains of V. parahaemolyticus showed two different SDS-PAGE wholecell protein patterns, giving the possibility of categorizing isolated strains in the same V. parahaemolyticus species into two subgroups. The 36 Vibrio isolates collected from sushi restaurants in Busan were all identified as V. parahaemolyticus by comparing their protein patterns with those of Vibrio type strains. The identified isolates were categorized into two different subgroups of V. parahaemolyticus. The whole-cell protein pattern analysis by SDS-PAGE can be used as a specific, rapid, and simple identification method for Vibrio spp. involved in foodborne diseases at the subspecies level.

Effect of wash treatments on reducing human norovirus on iceberg lettuce and perilla leaf.

Human noroviruses (NoVs) are major causes of nonbacterial gastroenteritis; they are transmitted by food and water, as well as person-to-person. The consumption of contaminated raw or uncooked food such as vegetables and fruits has been identified as a common source of human NoV outbreaks. In an effort to understand the survival and persistence of human NoVs on fresh produce, the efficacy of washing treatments in the removal of human NoVs from vegetables was evaluated. This study used artificially contaminated vegetables (iceberg lettuce and perilla leaf), and washing was done with tap water for convenience. Wash treatments included immersion in water, rinsing with running water, and a combination of immersion and rinsing (treatments I to III, respectively). The effect of a class I detergent, a commercial product used for washing fruits and vegetables, was also evaluated (treatment IV). After the wash treatments, the remnants of human NoVs on samples were measured via real-time reverse transcriptase PCR. The results varied among treatments and by vegetable. For iceberg lettuce, a reduction of 0.9 log was noted in the treatment III group. The wash treatment was more effective in the perilla leaf samples: each treatment significantly reduced the numbers of human NoVs (0.69- to 1.29-log reduction). These data demonstrated that wash treatments reduced numbers of virus from the surfaces of the vegetables. Therefore, washing would seem to be a basic step in reducing numbers of virus in food preparation and in viral transmission routes.

Evaluation of various PCR assays for the detection of emetic toxin producing Bacillus cereus.

Because conventional methods for detecting emetic-toxin-producing B. cereus are laborious and costly, various PCR assays, which are easy and cheap, have recently been reported. Therefore, this study estimated and compared the ability of various PCR assays to detect emetic-toxin-producing B. cereus strains isolated in Korea. The PCR assays were performed on 160 B. cereus strains, including 40 emetic-toxin-producing strains. Although the species-specific PCR assays were all shown to be highly specific, the sensitivities varied greatly. The accuracies of the primers were 97.5% (CER), 95.6% (EM1), 96.3% (RE234), 89.4% (CES), and 83.1% (Ces3R/CESR2). Moreover, the CER primer had a higher sensitivity (100%) than all the other primers tested, and a specificity of 96.7%. Thus, the CER primer was shown to be the most effective for screening the emetic-toxin-producing B. cereus strains tested in this study. However, the ability of these PCR assays to identify emetic-toxin-producing B. cereus should also be confirmed using other methods.

Single-step extraction followed by LC for determination of (fluoro)quinolone drug residues in muscle, eggs, and milk.

In this study, a simplified method for the extraction and determination of seven fluoroquinolone residues (danofloxacin, difloxacin, enrofloxacin, marbofloxacin, orbifloxacin, ofloxacin, and sarafloxacin) and three quinolones (oxolinic acid, flumequine, and nalidixic acid), in porcine muscle, table eggs, and commercial whole milk, which required no cleanup step, was devised. This procedure involves the extraction of analytes from the samples via liquid-phase extraction, and the subsequent quantitative determination was accomplished via LC-fluorescence detection. Analyte separation was successfully conducted on an XBridge-C(18) column, with a linear gradient mobile phase composed of acetonitrile and 0.01 M oxalic acid buffer at pH=3.5. The one-step liquid-liquid extraction method evidenced good selectivity, precision (RSDs=0.26-15.07%), and recovery of the extractable analytes, ranging from 61.12 to 115.93% in matrices. The LOQs ranged from 0.3 to 25 microg/kg. A survey of ten samples purchased from local markets was conducted, and none of the samples harbored fluoroquinolone residues. This method is an improvement over existing methodologies, since no additional cleanup was necessary.