Coffee-stained tooth enamel color restoration and surface abrasion with whitening and regular toothpaste.

PURPOSE: To evaluate the effectiveness of whitening toothpaste in restoring tooth color after coffee staining and its potential impact on enamel surfaces compared with regular toothpaste. METHODS: Bovine tooth enamel specimens were prepared and stained with coffee solutions before undergoing brushing simulation with different toothpaste slurries (whitening, regular, reference). For precise evaluation, spectrophotometric measurements were taken at intervals to assess color changes using the CIELAB (Commission Internationale de l'Éclairage Lab*) color space. Additionally, profilometric measurements were taken to determine the impact of toothpaste type on the roughness and abraded depth of the enamel surface. To understand the effects of toothpaste and brushing on color change, surface roughness, and abraded depth, while also considering correlations between these factors, the findings were analyzed using mixed-effects models. RESULTS: The whitening toothpaste group demonstrated the highest recovery rate (71%) after 10,000 brushstrokes, followed by the regular toothpaste group (48%) and the reference slurry group (43%). The mixed-effects model analysis revealed that the reference group had a smaller change in lightness (ΔL) than those in the regular toothpaste group. The whitening toothpaste group showed a greater change in lightness on average than those in the regular toothpaste group, with an increase in lightness as the number of brushstrokes increased. According to the roughness and abraded depth data, the whitening toothpaste group was least affected by brushing, while the reference and regular toothpaste groups showed higher levels of roughness and abraded depth at all intervals. CLINICAL SIGNIFICANCE: Gaining a thorough understanding of the effectiveness of whitening toothpaste and its impact on the enamel surface plays a crucial role in refining toothpaste formulations and advancing tooth whitening techniques in dental care.

Epigallocatechin-3-gallate suppresses hemin-aggravated colon carcinogenesis through Nrf2-inhibited mitochondrial reactive oxygen species accumulation.

BACKGROUND: Previous studies have presented evidence to support the significant association between red meat intake and colon cancer, suggesting that heme iron plays a key role in colon carcinogenesis. Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, exhibits anti-oxidative and anti-cancer effects. However, the effect of EGCG on red meat-associated colon carcinogenesis is not well understood. OBJECTIVES: We aimed to investigate the regulatory effects of hemin and EGCG on colon carcinogenesis and the underlying mechanism of action. METHODS: Hemin and EGCG were treated in Caco2 cells to perform the water-soluble tetrazolium salt-1 assay, lactate dehydrogenase release assay, reactive oxygen species (ROS) detection assay, real-time quantitative polymerase chain reaction and western blot. We investigated the regulatory effects of hemin and EGCG on an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon carcinogenesis mouse model. RESULTS: In Caco2 cells, hemin increased cell proliferation and the expression of cell cycle regulatory proteins, and ROS levels. EGCG suppressed hemin-induced cell proliferation and cell cycle regulatory protein expression as well as mitochondrial ROS accumulation. Hemin increased nuclear factor erythroid-2-related factor 2 (Nrf2) expression, but decreased Keap1 expression. EGCG enhanced hemin-induced Nrf2 and antioxidant gene expression. Nrf2 inhibitor reversed EGCG reduced cell proliferation and cell cycle regulatory protein expression. In AOM/DSS mice, hemin treatment induced hyperplastic changes in colon tissues, inhibited by EGCG supplementation. EGCG reduced the hemin-induced numbers of total aberrant crypts and malondialdehyde concentration in the AOM/DSS model. CONCLUSIONS: We demonstrated that EGCG reduced hemin-induced proliferation and colon carcinogenesis through Nrf2-inhibited mitochondrial ROS accumulation.

Optogenetic Stimulation of the Anterior Cingulate Cortex Modulates the Pain Processing in Neuropathic Pain: A Review.

Neuropathic pain is characterized by hypersensitivity, hyperalgesia, and allodynia, which is caused by damage to the somatosensory nervous system. It substantially impairs the quality of life. The management of neuropathic pain is challenging and should comprise alternative therapies. Researchers working on neural modulation methods in the field of optogenetics have recently referred to novel techniques that involve the activation or inhibition of signaling proteins by specific wavelengths of light. The use of optogenetics in neuropathic pain facilitates the investigation of pain pathways involved in chronic pain and has the potential for therapeutic use. Neuropathic pain is often accompanied by negative stimuli involving a broad network of brain regions. In particular, the anterior cingulate cortex (ACC) is a part of the limbic system that has highly interconnected structures involved in processing components of pain. The ACC is a key region for acute pain perception as well as the development of neuropathic pain, characterized by long-term potentiation induced in pain pathways. The exact mechanism for neuropathic pain in the ACC is unclear. Current evidence supports the potential of optogenetics methods to modulate the neuronal activity in the ACC for neuropathic pain. We anticipate the neuronal modulation in the ACC will be used widely to manage neuropathic pain.

Stimulating GABAergic Neurons in the Nucleus Accumbens Core Alters the Trigeminal Neuropathic Pain Responses in a Rat Model of Infraorbital Nerve Injury.

The nucleus accumbens core (NAcc) is an important component of brain reward circuitry, but studies have revealed its involvement in pain circuitry also. However, its effect on trigeminal neuralgia (TN) and the mechanism underlying it are yet to be fully understood. Therefore, this study aimed to examine the outcomes of optogenetic stimulation of NAcc GABAergic neurons in an animal model of TN. Animals were allocated into TN, sham, and control groups. TN was generated by infraorbital nerve constriction and the optogenetic virus was injected into the NAcc. In vivo extracellular recordings were acquired from the ventral posteromedial nucleus of the thalamus. Alterations of behavioral responses during stimulation "ON" and "OFF" conditions were evaluated. In vivo microdialysis was performed in the NAcc of TN and sham animals. During optogenetic stimulation, electrophysiological recordings revealed a reduction of both tonic and burst firing activity in TN animals, and significantly improved behavioral responses were observed as well. Microdialysis coupled with liquid chromatography/tandem mass spectrometry analysis revealed significant alterations in extracellular concentration levels of GABA, glutamate, acetylcholine, dopamine, and citrulline in NAcc upon optic stimulation. In fine, our results suggested that NAcc stimulation could modulate the transmission of trigeminal pain signals in the TN animal model.

Activation of CamKIIα expressing neurons on ventrolateral periaqueductal gray improves behavioral hypersensitivity and thalamic discharge in a trigeminal neuralgia rat model.

BACKGROUND: Preceding studies have reported the association of chronic neuropathic orofacial pain with altered ongoing function in the ventrolateral periaqueductal gray (vlPAG). However, its role in trigeminal neuralgia (TN) lacks attention. We here reported the aspect that vlPAG neurons play in TN nociceptive processing by employing excitatory neuron-specific optogenetic approaches. METHODS: TN was generated via unilateral infraorbital nerve chronic constriction in Sprague Dawley rats which induced mechanical and thermal pain sensitivity in air puff and acetone test, respectively. Channelrhodopsin conjugated virus with CamKIIα promoter was used to specifically activate the excitatory vlPAG neuronal population by optogenetic stimulation and in vivo microdialysis was done to determine its effect on the excitatory-inhibitory balance. In vivo extracellular recordings from ventral posteromedial (VPM) thalamus were assessed in response to vlPAG optogenetic stimulation. Depending on the experimental terms, unpaired student's t test and two-way analysis of variance (ANOVA) were used for statistical analysis. RESULTS: We observed that optogenetic activation of vlPAG subgroup neurons markedly improved pain hypersensitivity in reflexive behavior tests which was also evident on microdialysis analysis with increase glutamate concentration during stimulation period. Decreased mean firing and burst rates were evident in VPM thalamic electrophysiological recordings during the stimulation period. Overall, our results suggest the optogenetic activation of vlPAG excitatory neurons in a TN rat model has pain ameliorating effect. CONCLUSIONS: This article presents the prospect of pain modulation in trigeminal pain pathway via optogenetic activation of vlPAG excitatory neurons in rat model. This outlook could potentially assist vlPAG insight and its optogenetic approach in trigeminal neuropathic pain which aid clinicians endeavoring towards enhanced pain relief therapy in trigeminal neuralgia patients.

Ventralis oralis anterior (Voa) deep brain stimulation plus Gamma Knife thalamotomy in an elderly patient with essential tremor: A case report.

RATIONALE: Deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim) provides a safe and effective therapy for medically refractory essential tremor (ET). However, DBS may be risky in elderly patients and those with ischemic brain lesions. Gamma Knife radiosurgery (GKS) is a minimally invasive procedure, but bilateral thalamotomy is dangerous. PATIENT CONCERNS: We report a case of ventralis oralis anterior nucleus (Voa) DBS for dominant hand tremor plus Voa GKS for nondominant hand tremor in a very elderly patient with medically intractable ET. DIAGNOSIS: An 83-year-old right-handed woman visited our hospital with a medically intractable ET. Because of the ischemic lesion in the right basal ganglia, we decided to perform left unilateral DBS instead of bilateral DBS. INTERVENTION: We chose Voa as the target for DBS because, clinically, her tremor was mainly confined to her hands, and Voa had better intraoperative microelectrode recording results than Vim. OUTCOMES: After 2 years, her right-hand tremor remained in an improved state, but she still had severe tremor in her left hand. Therefore, we performed GKS targeting the right Voa. One year after surgery, the patient's hand tremor successfully improved without any complications. LESSONS: Salvage Voa GKS after unilateral Voa DBS is a valuable option for very elderly patients and patients with ischemic brain lesions. We suggest that Voa GKS thalamotomy is as useful and safe a surgical technique as Vim GKS for dystonic hand tremor. To the best of our knowledge, this is the first case report using salvage Voa as the only target for ET.

The Effect of Optogenetic Inhibition of the Anterior Cingulate Cortex in Neuropathic Pain Following Sciatic Nerve Injury.

Cortical disinhibition is the underlying pathological alteration contributing to neuropathic pain associated with peripheral nerve injury. Nerve injury resulting in disinhibition of the anterior cingulate cortex has been reported. However, the effect of optogenetic inhibition of the anterior cingulate cortex (ACC) on the sensory component of nerve injury-induced neuropathic pain has not been well studied. To investigate the feasibility of optogenetic ACC modulation, we injected an optogenetic virus or a null virus into the ACC of a nerve injury-induced neuropathic pain model. The unilateral ACC was modulated, and the optogenetic effect was measured by mechanical and thermal sensitivity tests. The assessment was performed in "pre-light off," "stimulation-yellow light on," and "post-light off" states. Optogenetic inhibition of the ACC in injury models revealed improved mechanical and thermal latencies with profound pain-relieving effects against nerve injury-induced neuropathic pain. The sensory thalamic discharge in electrophysiological in vivo recordings was also altered during laser stimulation. This finding indicates that hyperactivity of the ACC in nerve injury increases output to the spinothalamic tract through direct or indirect pathways. The direct photoinhibition of ACC neurons could play a vital role in restoring equilibrium and provide novel insight into techniques that can assuage peripheral nerve injury-induced neuropathic pain.

Pain modulation effect on motor cortex after optogenetic stimulation in shPKCγ knockdown dorsal root ganglion-compressed Sprague-Dawley rat model.

Neuropathic pain can be generated by chronic compression of dorsal root ganglion (CCD). Stimulation of primary motor cortex can disrupt the nociceptive sensory signal at dorsal root ganglion level and reduce pain behaviors. But the mechanism behind it is still implicit. Protein kinase C gamma is known as an essential enzyme for the development of neuropathic pain, and specific inhibitor of protein kinase C gamma can disrupt the sensory signal and reduce pain behaviors. Optogenetic stimulation has been emerged as a new and promising conducive method for refractory neuropathic pain. The aim of this study was to provide evidence whether optical stimulation of primary motor cortex can modulate chronic neuropathic pain in CCD rat model. Animals were randomly divided into CCD group, sham group, and control group. Dorsal root ganglion-compressed neuropathic pain model was established in animals, and knocking down of protein kinase C gamma was also accomplished. Pain behavioral scores were significantly improved in the short hairpin Protein Kinase C gamma knockdown CCD animals during optic stimulation. Ventral posterolateral thalamic firing inhibition was also observed during light stimulation on motor cortex in CCD animal. We assessed alteration of pain behaviors in pre-light off, stimulation-light on, and post-light off state. In vivo extracellular recording of the ventral posterolateral thalamus, viral expression in the primary motor cortex, and protein kinase C gamma expression in dorsal root ganglion were investigated. So, optical cortico-thalamic inhibition by motor cortex stimulation can improve neuropathic pain behaviors in CCD animal, and knocking down of protein kinase C gamma plays a conducive role in the process. This study provides feasibility for in vivo optogenetic stimulation on primary motor cortex of dorsal root ganglion-initiated neuropathic pain.

Section Plane Effects on Morphometric Values of Microcomputed Tomography.

OBJECTIVES: Histomorphometry is the established gold standard for inspection of trabecular microstructures in biomaterial research. However, microcomputed tomography can provide images from the perspective of various section planes. The aim of the present study was to evaluate the effects of different section planes, which may cause bias in two-dimensional morphometry, on the morphometric values of microcomputed tomography. METHODS: A socket preservation technique was performed on the extracted premolar area of 4 beagle dogs. After an 8-week healing period, a total of 16 specimens were obtained and analyzed with conventional histomorphometry and microtomographic morphometry. Using the original images of the histologic specimens for comparison, the most similar tomographic image was selected by trial and error. Then, the section plane was then moved with ±79 µm parallel offsets and rotated ±10° around the center from the occlusal view. The images were compared in terms of bone, graft, and noncalcified area, and the concordance correlation coefficient (CCC) was calculated. RESULTS: There was a high CCC in the comparison between histomorphometric images and the most similar microtomographic images. However, the CCC value was low in the comparisons with both parallel movement and rotation. Our results demonstrate that the sectioning plane has a significant effect on measurements. CONCLUSION: Two-dimensional morphometric values for biomaterial research should be interpreted with caution, and the simultaneous use of complementary 3-dimensional tools is recommended.

Effect of optogenetic modulation on entopeduncular input affects thalamic discharge and behavior in an AAV2-α-synuclein-induced hemiparkinson rat model.

OBJECTIVE: Neuromodulation of the globus pallidus internus(GPi) alleviates Parkinson's disease symptoms. The primate GPi is homologous to the rat entopeduncular nucleus (EP). The aim of the present study was to determine if optogenetic modulation of the EP could alter parkinsonian behavior or thalamic discharge in a hemiparkinson rat model. METHODS: We injected an adeno-associated virus type-2 expressing α-synuclein (AAV2-α-syn) into the substantia nigra pars compacta (SNc) of the right hemisphere and confirmed parkinsonian behavior using an amphetamine-induced rotation test. Then we injected activated or inhibited neurons, using the channelrhodopsin2 (ChR2)/halorhodopsin (NpHR) system in the EP of the hemiparkinson rat model and examined downstream effects in vivo. We assessed alterations in parkinsonian behaviors using the stepping and cylinder tests before, during, and after optogenetic stimulation. RESULTS: Importantly, optogenetic inhibition of the EP improved parkinsonian motor behaviors. When we monitored thalamic neuronal activity following optogenetic neuromodulation in vivo, and we observed alterations in thalamic discharge The thalamic neuronal activity is increased for optogenetic inhibition stimulation, whereas decreased for optogenetic activation stimulation. CONCLUSIONS: Taken together, our data demonstrate that optical neuromodulation of the EP can successfully control contralateral forelimb movement and thalamic discharge in an AAV2-α-synuclein-induced hemiparkinson rat model.

Anticancer effects of Ixeris dentata (Thunb. ex Thunb.) nakai extract on human melanoma cells A375P and A375SM.

ETHNOPHARMACOLOGICAL RELEVANCE: The plant species Taraxacum coreanum (TC), Youngia sonchifolia (YS), and Ixeris dentata (ID) belong to the family Compositae and are used for medicinal purposes in traditional medicine. However, the anticancer effects of TC, YS, and ID extracts and the underlying molecular mechanisms in melanoma cells have not been elucidated. AIM OF THE STUDY: To investigate the potential anticancer effects of TC, YS, and ID extracts on human melanoma cells and explore the potential pharmacological mechanisms in vitro and in vivo. MATERIALS AND METHODS: In this comparative study, we investigated the effects of TC, YS, and ID extracts on cell proliferation in human melanoma A375P and A375SM cells using MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays. Apoptotic cells were detected by 4',6-diamidino-2-phenylinodole (DAPI) staining. We also investigated whether the growth-inhibitory effects were associated with the induction of apoptosis and whether the mechanisms of cell death were the result of signaling molecules such as p53, Bax, Bcl-2, caspase-9, Poly-ADP ribose polymerase (PARP), and Erk (Extracellular signal-regulated protein kinase) 1/2. The in vivo antitumor effects were evaluated by measuring the tumor volume and weight and performing Terminal deoxynucleotidyl transferase (TdT) dUTP Nick End Labeling (TUNEL) assay and immunohistochemistry (IHC) in tumor xenograft models. RESULTS: TC, YS, and ID extracts effectively inhibited the growth of A375P and A375SM cells. In addition, several apoptotic events were observed following treatment, including DNA fragmentation and chromatin condensation by DAPI staining. The extracts increased p53, Bax, cleaved-caspase-9 and cleaved-PARP expression, whereas the expression of Bcl-2 was decreased in both cell lines. Furthermore, ID extract significantly inhibited the activation of Erk1/2 in both cell lines. Among the three extracts, ID had the strongest apoptotic effects. The administration of ID extract to mice inhibited tumor growth without any toxicity following 4 weeks of treatment. This extract increased the expression of apoptotic cells and p53 protein and decreased phospho-Erk1/2 protein. CONCLUSION: TC, YS, and ID extracts suppress the growth of human melanoma cells through apoptosis. Among these extracts, ID has the strongest anticancer and apoptotic effects. It induces apoptosis through the inhibition of Erk1/2 in A375P and A375SM human melanoma cells and in tumor xenograft models and may be a potential chemotherapeutic agent against melanoma.

Antitumor and apoptosis-inducing effects of α-mangostin extracted from the pericarp of the mangosteen fruit (Garcinia mangostana L.)in YD-15 tongue mucoepidermoid carcinoma cells.

α-mangostin is a dietary xanthone which has been shown to have antioxidant, anti-allergic, antiviral, antibacterial, anti-inflammatory and anticancer effects in various types of human cancer cells. In the present study, we aimed to elucidate the molecular mechanisms responsible for the apoptosis-inducing effects of α-mangostin on YD-15 tongue mucoepidermoid carcinoma cells. The results from MTT assays revealed that cell proliferation significantly decreased in a dose-dependent manner in the cells treated with α-mangostin. DAPI staining illustrated that chromatin condensation in the cells treated with 15 µM α-mangostin was far greater than that in the untreated cells. Flow cytometric analysis indicated that α-mangostin suppressed YD-15 cell viability by inducing apoptosis and promoting cell cycle arrest in the sub-G1 phase. Western blot analysis of various signaling molecules revealed that α-mangostin targeted the extracellular signal­regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) signaling pathways through the inhibition of ERK1/2 and p38 phosphorylation in a dose­dependent manner. α-mangostin also increased the levels of Bax (pro-apoptotic), cleaved caspase-3, cleaved caspase-9 and cleaved-poly(ADP-ribose) polymerase (PARP), whereas the levels of the anti-apoptotic factors, Bcl-2 and c-myc, decreased in a dose-dependent manner. The anticancer effects of α-mangostin were also investigated in a tumor xenograft mouse model. The α-mangostin-treated nude mice bearing YD-15 tumor xenografts exhibited a significantly reduced tumor volume and tumor weight due to the potent promoting effects of α-mangostin on cancer cell apoptosis, as determined by TUNEL assay. Immunohistochemical analysis revealed that the level of cleaved caspase-3 increased, whereas the Ki-67, p-ERK1/2 and p-p38 levels decreased in the α-mangostin­treated mice. Taken together, the findings of our study indicate that α-mangostin induces the apoptosis of YD-15 tongue carcinoma cells through the ERK1/2 and p38 MAPK signaling pathways.

Fermented Prunus mume with probiotics inhibits 7,12-dimethylbenz[a]anthracene and 12-o-tetradecanoyl phorbol-13-acetate induced skin carcinogenesis through alleviation of oxidative stress.

Maesil (Prunus mume Siebold and Zucc.), a member of the genus Rosaceae, has been reported to have antioxidative effects, as well as anticancer influence in many cancer lines. Thus, this present study was designed to investigate the inhibitory effect of fermented Maesil with probiotics against 7,12-dimethylbenz[a]anthracene (DMBA), 12-O-tetradecanoyl phorbol 13-acetate (TPA)-induced mouse skin carcinogenesis via its antioxidative potential. Mice were fed a diet containing fermented Maesil, containing either 1% (1% FM fed group) or 2% (2% FM fed group) along with probiotics following DMBA and TPA exposure. Continuous ingestion of the experimental feed markedly inhibited skin carcinogenesis, as evidenced by a marked decrease in papilloma numbers and epidermal hyperplasia as well as cellular proliferation and the percentage of proliferating-cell nuclear antigen positive cells. Also, the FM fed group showed an increase of total antioxidant capacity as well as an increased level of phase II detoxifying enzymes such as superoxide dismutase, concurrent with a decreased lipid peroxidation activity level. Taken together, these results suggest that fermented Maesil has the ability to suppress the development of DMBA-TPA induced skin carcinogenesis, via the reduction of lipid peroxidation, enhancing total antioxidant capacity and phase II detoxifying enzyme.

Bilateral globus pallidus internus deep brain stimulation for DYT1+ generalized dystonia with previously received bilateral thalamotomy and unilateral pallidotomy.

Ablation of the globus pallidus internus (GPi) and thalamotomy have been extensively used in the past. Posteroventral GPi deep brain stimulation has been considered as a treatment for dystonia. However, to date, there is no report in the literature of any dystonia patient who underwent GPi deep brain stimulation who had previously undergone staged bilateral thalamotomy and unilateral pallidotomy. The authors of the present study have acquired relatively good clinical results, even in patients who previously received bilateral thalamotomy and unilateral pallidotomy for DYT1+ primary generalized dystonia.

Apoptotic effect of quercetin on HT-29 colon cancer cells via the AMPK signaling pathway.

Activation of AMP-activated protein kinase (AMPK), a physiological cellular energy sensor, strongly suppresses cell proliferation in both nonmalignant and tumor cells. This study demonstrates the mechanism of quercetin-induced apoptosis in HT-29 colon cancer cells. Treatment of cells with quercetin significantly decreased cell viability in a dose-dependent manner. Notably, quercetin increased cell cycle arrest in the G1 phase and up-regulated apoptosis-related proteins, such as AMPK, p53, and p21, within 48 h. Furthermore, in vivo experiments showed that quercetin treatment resulted in a significant reduction in tumor volume over 6 weeks, and apoptosis-related protein induction by quercetin was significantly higher in the 100 mg/kg treated group compared to the control group. All of these results indicate that quercetin induces apoptosis via AMPK activation and p53-dependent apoptotic cell death in HT-29 colon cancer cells and that it may be a potential chemopreventive or therapeutic agent against HT-29 colon cancer.

Radix clematidis extract inhibits UVB-induced MMP expression by suppressing the NF-kappaB pathway in human dermal fibroblasts.

Ultraviolet (UV)B irradiation induces the production of matrix metalloproteinases (MMPs), which are responsible for the degradation of collagenous extracellular matrix in connective tissues, causing skin photoaging. Although Radix clematidis is commonly used in Chinese medicine for the treatment of arthralgia, the anti-skin photoaging effects of Radix clematidis have not yet been reported. In the present study, we investigated the inhibitory effects of Radix clematidis extract (RCE) on MMP-1 and -3 expression of human dermal fibroblast cells via various in vitro experiments and elucidated the pathways of inhibition. Western blot analysis and real-time PCR revealed RCE inhibited UVB-induced MMP-1 and -3 expressions in a dose-dependent manner. UVB strongly activated nuclear factor-kappaB (NF-kappaB) activity, which was determined by IkappaBalpha degradation, nuclear localization of p50 and p65 subunit, and NF-kappaB binding activity. However, UVB-induced NF-kappaB activation was completely blocked by RCE pretreatment. These findings suggest that RCE prevents UVB-induced MMP expression through inhibition of NF-kappaB activation. In conclusion, RCE is a potential agent for the prevention and treatment of skin photoaging.

A multiresidue method for the analysis of pesticide residues in polished rice (Oryza sativa L.) using accelerated solvent extraction and gas chromatography and confirmation by mass spectrometry.

An analytical procedure using accelerated solvent extraction and gas chromatography with an electron capture detector has been optimized to simultaneously determine the residue of two insecticides (diazinon and EPN) and one fungicide (isoprothiolane) in polished rice and was confirmed by GC-mass spectrometry. Several parameters, including temperature, pressure, solvent ratio, cell size and cell cycle, were thoroughly investigated to find the optimal extraction conditions. The average recoveries of the three pesticides were between 82.7 and 126.4% at spiking levels of 0.1 and 0.5 ppm. The relative standard deviations were less than 7% for all of the recovery tests. The optimum accelerated solvent extraction operating conditions were 100 degrees C, 1500 atm, acetone-n-hexane (20:80 v/v) as the extraction solvent, two cycles, and a cell size of 33 ml. The total extraction time was approximately 20 min. The optimized procedure has also been applied to the determination of diazinon, isoprothiolane and EPN in real rice samples. In conclusion, accelerated solvent extraction was used for the first time for the analysis of diazinon, isoprothiolane and EPN in polished rice and offers the possibility of a fast and simple process for obtaining a quantitative extraction of the studied pesticides.

Pesticide multiresidue analysis in Panax ginseng (C. A. Meyer) by solid-phase extraction and gas chromatography with electron capture and nitrogen-phosphorus detection.

An analytical multi-residue method using gas chromatography coupled with electron capture and a nitrogen-phosphorus detector was investigated for the simultaneous determination of 18 commonly used insecticides and fungicides in Korean ginseng (Panax ginseng C. A. Meyer). Samples were previously extracted with an acetonitrile and cleaned up by solid-phase extraction (SPE). The calibration curves were linear, with determination coefficients higher than 0.989. Recoveries at concentrations between 0.01 and 14.9 ppm ranged from 72.3 to 117.2%, with precision, which was expressed as relative standard deviation (RSD), at values lower than 5%. The proposed method was applied to the determination of pesticide levels from 12 ginseng samples, taken from four different agricultural areas of Jeonnam province, where several insecticides and fungicides were applied. Except in one sample, tolclofos-m was the only pesticide contained at a level lower than the maximum residue limits (MRL) authorized by the Korea Food and Drug Administration (KFDA) in real ginseng samples grown for 4, 5 and 6 years.