Solid-phase microextraction for determining the distribution of sixteen US Environmental Protection Agency polycyclic aromatic hydrocarbons in water samples

A solid-phase microextraction (SPME) procedure has been developed for the determination of 16 US Environmental Protection Agency promulgated polycyclic aromatic hydrocarbons (PAHs). Five kinds of SPME fibers were used and compared in this study. The extracted sample was analyzed by gas chromatography with flame ionization detection or mass spectrometry. Parameters affecting the sorption of analyte into the fibers, including sampling time, thickness of the fiber coating, and the effect of temperature, have been examined. Moreover, the feasibility of headspace SPME with different working temperatures was evaluated. The method was also applied to real samples. The 85-microm polyacrylate (PA) and 100-microm poly(dimethylsiloxane) (PDMS) fibers were shown to have the highest affinities for the selected PAHs. The PA fiber was more suitable than the PDMS fiber for the determination of low-ring PAHs while high sensitivity of high-ring PAHs was observed when a 100-microm PDMS fiber was used. The method showed good linearity between 0.1 and 100 ng/ml with regression coefficients ranging from 0.94 to 0.999. The reproducibility of the measurements between fibers was found to be very good. The precisions of PA and PDMS fibers were from 3 to 24% and from 3 to 14%, respectively. Headspace SPME is a valid alternative for the determination of two- to five-ring PAHs. A working temperature of 60 degrees C provides significant enhancement in sensitivity of two- to five-ring PAHs having low vapor pressures (>10(-6) mmHg at 25 degrees C) (1 mmHg = 133.3 Pa) and low Henry's constants (>10 atm ml/mol) (1 atm = 1.01 x 10(5) Pa).

[Effects of the interaction between histone and hAMFR gene promoter on the transcription activity in vitro]

The effects of interaction between histones and human autocrine motility factor receptor (hAMFR) gene promoter on the transcription activity in vitro was investigated by using histones purified from chicken erythrocytes, HeLa cell nuclear extracts and heat-treated supernatants of Xenopus eggs. The results showed that the competitive binding of histones and transcription factors at the promoter of hAMFR gene was very important to the transcription in vitro. If a pre-initiation complex was formed with HeLa cell nuclear extracts on the promoter prior to nucleosome assembly, it would prevent nucleosome-mediated transcription repression. When the nucleosome was assembled on the promoter in advance, the transcription activity could be repressed. When histones and HeLa cell nuclear extracts were mixed in the reaction simultaneously, the transcription activity would depend on the relative amount of histones to that of HeLa cell nuclear extracts.

Protein sequence analysis and mapping of IgE and IgG epitopes of an allergenic 98-kDa Dermatophagoides farinae paramyosin, Der f 11

BACKGROUND

A 98-kDa mite paramyosin (Der f 11) from Dermatophagoides farinae (Df) is highly allergenic, and its cDNA (Df642) has been cloned. This paper describes the sequence characteristics and the mapping of the immunodominant human IgE and IgG epitopes of Der f 11.

METHODS

The protein sequence analysis was performed with a combination of FASTA, GCG, and CLUSTAL W computing packages. The whole cDNA insert and its PCR-derived DNA fragments were generated and expressed in E. coli. These overlapping recombinant peptides (F1 to F5) were used for B-cell epitope mapping with 18 mite-allergic sera by dot immunoassays.

RESULTS

Df642 cDNA encodes a partial sequence that contains the 2nd to 26th 28-residue repeats and lacks the N-terminus and the C-terminus. The sequence identity of Der f 11 with other known paramyosins is 34-60%. The dominant IgE epitopes are located in peptides F1 and F4, whereas the dominant IgG epitopes are located in peptides F1 and F2. These peptides are more reactive than whole rDf642.

CONCLUSIONS

Mite paramyosin is very similar to other known paramyosins. The human IgE and IgG epitopes are scattered throughout the entire molecule. Data also indicate the presence of unique IgE and IgG epitopes in Der f 11.

[Binding and interaction of histones and transcription factors on the promoter of hAMFR gene]

In this study, histone H1, core histones H2A-H2B and H3-H4 were purified from chicken erythrocytes by hydroxylapatile chromatography. The nuclear extract was prepared from HeLa cells. We investigated the binding and interaction of histones and transcription factors on the upstream sequence of human autocrine motility factor receptor (hAMFR) gene by gel shift mobility assay. We found that the binding of H1 on the promoter sequence of hAMFR gene was relatively stable. We propose that H1 plays an important role in stablizing chromatosome. We also found that histones and HeLa cell extract could form a ternary complex with the DNA template.

Dietary intake and residues of organochlorine pesticides in foods from Hsinchu, Taiwan

The levels of contamination with various organochlorine pesticides (such as total HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endosulfan, and total DDT) of different foods from 3 traditional markets were determined to estimate Taiwanese daily intake of organochlorine pesticides. Of the 18 organochlorine pesticides investigated, alpha-HCH, beta-HCH, lindane, delta-HCH, heptachlor, heptachlor epoxide, dieldrin, endrin, alpha-endosulfan, p,p'-DDE, and p,p'-DDT were detected at concentrations ranging from 0.26 to 10.2 ng/g wet weight. Contamination with organochlorine pesticides followed the order heptachlor > dieldrin > alpha-endosulfan > HCH isomers > heptachlor epoxide > DDT. Frequencies of detection of organochlorine pesticide residues ranged from 2.0 to 52.3%. alpha-Endosulfan was the most frequently detected organochlorine pesticide in the foods analyzed, followed by heptachlor epoxide (47.6%) and alpha-HCH (38.9%). Estimated daily intakes (EDIs) of organochlorine pesticides from foods were 1.137 micrograms for total HCH, 2.147 micrograms for heptachlor, 0.702 microgram for heptachlor epoxide, 0.624 microgram for endosulfan, 0.098 microgram for cyclodiene, and 0.541 microgram for total DDT. These EDIs were only 0.075% of the acceptable daily intake (ADI) for lindane, 47.5% of ADI for heptachlor and heptachlor epoxide, 0.045% of ADI for total DDT, and 1.01% of ADI for aldrin and dieldrin. Therefore, consumption of the foods analyzed does not pose a risk to consumer health.

Gastric adenocarcinoma with tonsil and submaxillary gland metastases: case report

Local invasion, hematogenous and lymphatic metastases are the major modes of spreading gastric cancer. The most common sites of metastases in patients with gastric cancer are liver, peritoneum, omentum, lungs and mesentery. Of the two pathological types of gastric cancer, intestinal-type gastric cancer showed preferential metastasis to the liver, whereas the diffuse-type showed a preference for peritoneal involvement and lymph node metastasis. However, metastases of gastric cancer to the head and neck regions are not common. The hematogenous route appears to account for a great majority of metastases to the head and neck regions. Malignant neoplasm metastases to major salivary glands or tonsils are not common. Several patients with cancers from the infraclavicular area have been reported with parotid gland or tonsil metastases. However, metastasis of gastric adenocarcinoma to the tonsils or submandibular glands is rare. We present a patient with recurrent gastric adenocarcinoma with both tonsil and submandibular gland metastases which is even rarer.

Antibody responses to an immunodominant nonstructural 1 synthetic peptide in patients with dengue fever and dengue hemorrhagic fever

Two flaviviruses, dengue (DEN) virus and Japanese encephalitis (JE) virus, are important because of their global distribution and the frequency of epidemics in tropical and subtropical areas. To study the B-cell epitopes of nonstructural 1 (NS1) glycoprotein and anti-NS1 antibody response in DEN infection, a series of 15-mer synthetic peptides from the predicted B-cell linear epitopes of DEN-2 NS1 protein were prepared. Enzyme-linked immunosorbent assay (ELISA) was performed to analyze antibody responses to these peptides from sera of both DEN and JE patients. One peptide derived from DEN-2 NS1, D2 NS1-P1 (amino acids 1-15), was identified as the immunodominant epitope that reacted with sera from dengue fever (DF) patients but not JE patients. The isotype of D2 NS1-P1-specific antibodies was mainly immunoglobulin M (IgM) in all sera that tested positive. A specificity study demonstrated that sera from all four DEN types reacted with D2 NS1-P1. A dynamics study showed that specific antibodies to this peptide could be detected as early as 2 days after the onset of symptoms. We observed significant anti-D2 NS1-P1 antibody responses in 45% of patients with primary and secondary infections with DF or with dengue hemorrhagic fever. This is the first report demonstrating that significant anti-DEN NS1 antibodies can be induced in the sera of patients with primary DEN infection.

Antiapoptotic but not antiviral function of human bcl-2 assists establishment of Japanese encephalitis virus persistence in cultured cells

Upon infection of Japanese encephalitis virus (JEV), baby hamster kidney (BHK-21) and Chinese hamster ovary (CHO) cells were killed by a mechanism involved in apoptosis. While readily established in a variety of cell lines, JEV persistence has never been successfully instituted in BHK-21 and CHO cells. Since stable expression of human bcl-2 in BHK-21 cells has been shown to delay JEV-induced apoptosis, in this study we investigated whether JEV persistence could be established in such cells. When constitutively expressing bcl-2, but not its closest homolog, bcl-XL, following a primary lytic infection, approximately 5 to 10% of BHK-21 and CHO cells became persistently JEV infected during a long-term culture. From the persistent bulks, several independent clones were selected and expanded to form stable cell lines that continuously produced infectious virus without marked cytopathic effects (CPE). Among these stable cell lines, the truncated nonstructural protein 1 (NS1) was also detected and was indistinguishable from the NS1 truncations previously observed in JEV-persistent murine neuroblastoma N18 cells. However, the stable expression of NS1 alone, regardless of whether it was truncated or full length, failed to render the engineered cells persistently infected by JEV, implying that aberrant NS1 proteins were likely a consequence of, rather than a cause for, the viral persistence. Enforced bcl-2 expression, which did not affect virus replication and spread during the early phase of cytolytic infection, appeared to attain JEV persistence by restriction of virus-induced CPE. Our results suggest that it is the antiapoptotic, rather than the antiviral, effect of cellular bcl-2 which plays a role in the establishment of JEV persistence.

Need for certainty and interest in genetic testing

The relation among need for certainty, type of information presented about a genetic test, and level of interest in predictive genetic testing was examined. Participants were randomly assigned to receive 1 of 2 descriptions of the test. The only difference between the descriptions was that one included a paragraph that emphasized the cancer risk remaining for those who test negative for gene mutations. As predicted, a significant interaction between need for certainty and type of information presented was observed. Whereas women high in need for certainty were more interested in genetic testing when provided with the standard description and less interested when provided with the more complete one, women low in need for certainty showed the opposite pattern. The results suggest that interest in genetic testing is determined by the correspondence between an individual's personal goals and her perception of the kind of information provided by the test.

A comprehensive dynamical model of pulsatile secretion of the hypothalamo-pituitary-gonadal axis in man

We proposed a comprehensive dynamical model for the hormone secretion of the hypothalamo-pituitary-gonadal axis in man. This model is comprehensive and more reasonable than any previous model. A large number of deductions of this model agree well with experimental results.

Selective precipitation separation and inductively coupled plasma mass spectrometric determination of trace metal impurities in high purity silver

A simple and rapid method for the determination of some trace element impurities in high purity silver, combining the isolation of analytes from the silver matrix with selective precipitation followed by ICP-MS determination was developed. On the basis of an extreme difference in the solubilities of the chlorides of silver and the other accompanying trace elements, silver can be separated completely through the addition of hydrochloric acid. The sample of silver was at first dissolved in 7 M nitric acid followed by addition of hydrochloric acid to remove the silver matrix by formation of a silver chloride precipitate, while leaving the trace element impurities in the solution, which was subsequently analysed by ICP-MS. Eleven elements (Al, Au, Cd, Co, Cu, Fe, Mg, Mn, Ni, Pb and Sn) were determined with good accuracy and precision. The limits of detection (based on the 3 sigma criterion) of these elements were 10(-1)-10(-3) ng g-1. The proposed method was successfully applied to the determination of metal impurities in high-purity silver samples (EM9465 and EM 9343) and validated by the analysis of NIST SRM 8171 (Fine Silver FS 14).

Free energy calculations of the mutation of Ile96-->Ala in barnase: contributions to the difference in stability

Free energy calculations were carried out to determine the relative unfolding free energy of the Ile96 wild type and Ala96 mutant barnases. The total calculated free energies suggest that substitution of Ile96 with Ala destabilizes barnase by 3.9 kcal/mol, which is in good agreement with the independently determined experimental values of 4.0 and 3.3 kcal/mol and a previous simulation. However, a decomposition of the free energy finds the dominant contributions to this free energy arising from the noncovalent interactions between the perturbed group and distant residues of barnase in the sequence and water molecules and only a very small contribution from covalent interactions. This is in contrast to the previous simulation, using the dual topology methodology, which produced a decomposition with an approximately 60% free energy contribution from changes in covalent interactions. The use of the single topology employed in the present calculations and the dual topology employed in the previous study are analyzed in order to understand the contrast between the present results and the results of the previous study.

The interaction of the neuromuscular effects between mivacurium and esmolol in rats

BACKGROUND

To study the neuromuscular interaction between mivacurium and esmolol, we compared the neuromuscular actions of the ED90 dose of mivacurium both in the absence and presence of esmolol infusion.

METHODS

Twelve rats were anesthetized with urethane. Train-of-four stimulation was applied every 12 s to the sciatic nerve, and the electromyogram (EMG) response of the anterior tibial muscle was measured.

RESULTS

The ED50 and ED90 of mivacurium in rats were 144 +/- 7.3 micrograms/kg and 197 +/- 7.7 micrograms/kg, respectively. The maximal EMG depression produced by ED50 of mivacurium decreased significantly with esmolol treatment from 88.2 +/- 2.7% to 83.1 +/- 2.6% after esmolol infusion (p < 0.05). The onset time for 75% EMG depression was much shorter for control (44 +/- 6.3 s) than that of esmolol treatment (78.2 +/- 2.4 s; p < 0.05). There was no difference between their duration.

CONCLUSIONS

The results of this study demonstrated that esmolol does not potentiate the neuromuscular effect of mivacurium but antagonize the maximal neuromuscular block and decrease its onset time in rats.

Psychological minimization of cholesterol test results: moderators of appraisal in college students and community residents

College students received randomly assigned desirable or borderline-high cholesterol test results. Borderline-high Ss rated high cholesterol as a less serious threat to health, viewed the test as less accurate, and perceived high cholesterol as more common than did those given desirable readings. High self-esteem or blunting coping style predicted lower distress after borderline-high readings but did not moderate cognitive appraisal. In Study 2, minimization was again observed among participants in a community screening, primarily among those who had never been tested. Although the never-tested group was younger and less knowledgeable about cholesterol, these factors did not account for minimization. The results support the generalizability of laboratory data on risk appraisal and provide new evidence regarding the nature and determinants of threat minimization.

Multiresolution wavelet analysis of evoked potentials

Neurological injury, such as from cerebral hypoxia, appears to cause complex changes in the shape of evoked potential (EP) signals. To characterize such changes we analyze EP signals with the aid of scaling functions called wavelets. In particular, we consider multiresolution wavelets that are a family of orthonormal functions. In the time domain, the multiresolution wavelets analyze EP signals at coarse or successively greater levels of temporal detail. In the frequency domain, the multiresolution wavelets resolve the EP signal into independent spectral bands. In an experimental demonstration of the method, somatosensory EP signals recorded during cerebral hypoxia in anesthetized cats are analyzed. Results obtained by multiresolution wavelet analysis are compared with conventional time-domain analysis and Fourier series expansions of the same signals. Multiresolution wavelet analysis appears to be a different, sensitive way to analyze EP signal features and to follow the EP signal trends in neurologic injury. Two characteristics appear to be of diagnostic value: the detail component of the MRW displays an early and a more rapid decline in response to hypoxic injury while the coarse component displays an earlier recovery upon reoxygenation.

Psychological minimization of cholesterol test results: moderators of appraisal in college students and community residents

College students received randomly assigned desirable or borderline-high cholesterol test results. Borderline-high Ss rated high cholesterol as a less serious threat to health, viewed the test as less accurate, and perceived high cholesterol as more common than did those given desirable readings. High self-esteem or blunting coping style predicted lower distress after borderline-high readings but did not moderate cognitive appraisal. In Study 2, minimization was again observed among participants in a community screening, primarily among those who had never been tested. Although the never-tested group was younger and less knowledgeable about cholesterol, these factors did not account for minimization. The results support the generalizability of laboratory data on risk appraisal and provide new evidence regarding the nature and determinants of threat minimization.

Comparison of preoperative and postoperative iliohypogastric ilioinguinal nerve block for pediatric herniorrhaphy patients

The purpose of this study was to compare the effects of preoperative and postoperative iliohypogastric ilioinguinal nerve block (IINB) performed on 30 pediatric patients having elective unilateral herniorrhaphy for postoperative pain control and to discuss the theory of post-injury hypersensitivity of the nerves system. The patients were assigned into two groups (A = 15, B = 15) randomly. Both groups were given GA during the surgical procedure except that group A received IINB 15 minutes prior to skin incision and group B immediately after skin closure. The local anesthetic used was 0.25% bupivacaine and the dosage was 1 mg/Kg. The heart rate, BP, and anesthetic concentration (halothane) were recorded during the procedure and postoperative pain was assessed by using the modification of the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) behavior pain score which were taken at 1 hr, 3 hr (POR), 6 hr, and 24 hr (ward) postoperatively. Group A had less pain at 1 hr and 3 hr than group B postoperatively and is statistically significant. There was no statistically significant in pain score at 6 hr and 24 hr between the two groups.

Progression delay of prostate tumor skeletal metastasis effects by bisphosphonates

Prostate tumor cell metastasis to the axial skeleton was induced in male Copenhagen rats using the intravenous injection of syngeneic metastatic R3327-MATLyLu tumor cells and concomitant caval vein clamping. The proliferation of tumor cells in the lumbar region was monitored by the progression, within 19 days post tumor cell injection, of hindleg paralysis which appeared in these animals. Histology confirmed the presence of tumor cells within the lumbar spine in 100% of cases displaying hindleg paralysis. Treatment with either of the bisphosphonate drugs, Cl2MDP or APD, suppressed and delayed the development of hind leg paralysis. Bisphosphonate treatment may be expected to delay the onset of axial skeletal metastasis effects in prostate cancer patients.

Neural changes in acute arthritis in monkeys. II. Increased glutamate immunoreactivity in the medial articular nerve

Glutamate and other excitatory amino acids have been shown to play a key role in nociception and the hyperalgesia associated with the acute inflammatory response. In an effort to understand more fully the role of Glu in this process, we determined that there is Glu in a percentage of axons in the medial articular nerve (MAN) of monkeys, a source of preterminal afferent fibers innervating the knee joint. After induction of the experimental knee joint inflammation with a kaolin/carrageenan mixture, comparison was made of the percentage of Glu positive axons in the MAN on the side of the inflammation versus the contralateral MAN using post-embedding immunogold electron microscopic methods. A doubling in the percentage of Glu-containing axons was observed on the side of the experimental arthritis as compared to the MAN of the other side or of uninjected controls. Glu positive axons were unmyelinated or were included in the small, thinly myelinated group in control nerves. Following induction of the inflammation, axonal diameter measurements revealed an increase in Glu content primarily in the small, thinly myelinated axons, which correspond to the group III afferent fibers. These increases were observed in the anesthetized preparation only when injection of kaolin/carrageenan was combined with joint flexion and mechanical stimulation. The dramatic increase in percentages of fibers stainable for Glu in the MAN following the induction of inflammation suggests that Glu content is greatly increased in the afferent fibers and may be a major contributor to the enhanced responses of sensory neurons in inflammatory states such as arthritis.