Using dose addition to estimate cumulative risks from exposures to multiple chemicals

The Food Quality Protection Act (FQPA) of 1996 requires the EPA to consider the cumulative risk from exposure to multiple chemicals that have a common mechanism of toxicity. Three methods, hazard index (HI), point-of-departure index (PODI), and toxicity equivalence factor (TEF), have commonly been considered to estimate the cumulative risk. These methods are based on estimates of ED(10) (point of departure) and reference doses from the dose-response functions of individual chemicals. They do not incorporate the actual dose-response function of the mixture from multiple chemical exposures. Dose addition is considered to be an appropriate approach to cumulative risk assessment because it assumes that the chemicals of interest act in accordance with a common mode of action (a similar action). This paper proposes a formal statistical procedure to estimate the cumulative risk by fitting the dose-response model of the mixture under dose addition. The relative potency between two chemicals is estimated directly from the joint dose response model of the mixture. An example data set of four drugs representing four chemicals is used to illustrate the proposed procedure and compare it to the HI, PODI, and TEF methods.

Effect of nitric oxide on strophanthidin-induced ventricular tachycardia

Nitric oxide (NO) has been demonstrated to have several effects on the heart. Through the stimulation of guanylate cyclase, NO increases cyclic GMP and decreases intracellular calcium. The purpose of this study was to evaluate the effects of NO on ventricular arrhythmia induced by strophanthidin in guinea pigs and dogs. In experiment 1, after strophanthidin-induced ventricular tachycardia, guinea pigs received different doses of L-arginine (0, 25, 50, 100, 200, and 400 mg/kg; n = 10 for each dose), 200 mg/kg L-arginine combined with 100 mg/kg N(G)-nitro-L-arginine methylester (L-NAME, n = 10), or 200 mg/kg D-arginine (n = 10). In experiment 2, after strophanthidin-induced ventricular tachycardia, dogs (n = 7) received 200 mg/kg L-arginine. By 12-lead ECG, monophasic action potentials in left and right ventricles were recorded throughout the study. In experiment 1, guinea pigs which received 200 mg/kg or 400 mg/kg L-arginine had greater incidences of ventricular tachycardia termination (60 and 80%, respectively) than those which received 0, 25, 50, and 100 mg/kg L-arginine (0, 0, 20, and 30%, respectively), those which received L-arginine with L-NAME (0%), and those which received D-arginine (0%). In experiment 2, 5 (71%) of the dogs had successful termination of ventricular tachycardia. These findings suggest that L-arginine was effective in treating strophanthidin-induced ventricular tachycardia in vivo and that the underlying mechanism is through a NO pathway.

The in vitro inhibitory effect of tannin derivatives on 3-hydroxy-3-methylglutaryl-coenzyme a reductase on vero cells

Coronary heart disease is still the major cause of death in industrialized countries. Multiple primary or secondary interventional trials to lower serum cholesterol in humans have resulted in significant reduction of coronary events and death, one of the major reasons attributed to developing a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor such as pravastatin. Developing new inhibitors of cholesterol synthesis is still common in the pharmaceutical industry. Tannin comprises a large group of natural polyphenolic compounds possessing antioxidant effects. The methods for analysis of specific inhibitors of mevalonate biosynthesis have already been well established by using Vero cells, a cell line obtained from kidneys of African green monkeys. Tannin derivatives isolated from different traditional Chinese herbs were dissolved in DMSO and incubated with Vero cells with or without the addition of 1 mmol/l mevalonate or 5 mmol/l sodium acetate for 24 h in order to observe cell growth. Pravastatin, a specific HMG-CoA reductase inhibitor, was used as positive control which could inhibit Vero cells growth effectively and cell growth inhibition was reversible after adding 1 mmol/l mevalonate. More than 50 tannin derivatives were used for the study, but only two compounds - proanthrocyanidin A-2 (belonging to the flavan-3-ol group) and 1,2,3,6-tetra-O-galloyl-beta-D-glucose (belonging to the gallotannin group) - showed significant growth inhibition of Vero cells. This study showed that some isolated tannin derivatives from traditional herbs were effective HMG-CoA reductase inhibitors which might be developed into new hypocholesterolemic agents.

Three xanthones and a benzophenone from Garcinia mangostana

Investigation of the constituents of Garcinia mangostana has led to the isolation of four new compounds: three minor xanthones, garcimangosone A (1), garcimangosone B (2), and garcimangosone C (3), and a benzophenone glucoside, garcimangosone D (4). The structures of these four compounds were established by spectral (NMR and MS) and chemical methods.

Effects of ginsenosides from Panax ginseng on cell-to-cell communication function mediated by gap junctions

Gap junctions have been shown or are believed to be involved in the pathogenesis of many inherited and acquired human diseases. Agents that regulate the gap junction-mediated intercellular communication (GJIC) function may facilitate prevention and treatment of GJIC-involved diseases. In the present study we examined the effects of 27 ginsenosides isolated from Panax ginseng on GJIC. The results show that compounds 1 (oleanolic acid), 2 (ginsenoside-R0), 3 (ginsenoside-Rb1), 5 (ginsenoside-Rb2), 7 (ginsenoside-Rd), 8 (ginsenoside-Rg3), 12 (panaxadial), 13 (notoginsenoside-R4), 17 [ginsenoside-Rg2 (20S)], 18 (ginsenoside-Rf), and 26 (ginsenoside-F3) did not obviously affect GJIC, whereas compounds 4 (ginsenoside-Rc), 6 (ginsenoside-Rb3), 9 (ginsenoside-Rd2), 10 (notoginsenoside-Fe), 11 (ginsenoside-Rh2),14 (ginsenoside-Ra1), 15 (ginsenoside-Re), 16 [ginsenoside-Rg2 (20R)], 19 (ginsenoside-Ia), 20 [ginsenoside-Rh1 (20S)], 21 [ginsenoside-Rh1 (20R)], 22 (ginsenoside-F1), 23 (protopanaxatriol), 24 (panaxatriol), 25 (ginsenoside-Rg1), and 27 (chikusetsaponin-L8) induced GJIC reductions at various degrees. Compounds 2, 7, and 8 protected against the tyrosine phosphatase inhibitor vanadate-induced GJIC reduction, while compounds 1, 5, 7, and 17 inhibited the cytokine interleukin 1 alpha (IL-1alpha)-induced reduction in GJIC. Nevertheless, no compounds protected against the protein kinase C (PKC) activator 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced GJIC inhibition. On the other hand, GJIC reductions induced by compounds 6, 9,10, 20, 21, 22, 24, and 25 were inhibited by the tyrosine kinase (TK) inhibitor genistein, while GJIC reductions induced by compounds 6, 9, 14, 16, 19, 21, and 24 were attenuated in the presence of the PKC inhibitor calphostin C. However, GJIC reductions induced by compounds 4, 23, and 27 were not inhibited either by genistein or by calphostin C. These data indicate that various mechanisms are responsible for effects of ginsenosides on GJIC.

Taxane diterpenoids from the stem bark of Taxus mairei

Three new 11(15-->1)-abeo-taxanes, taxumairols U-W (1-3), have been isolated from extracts of the stem bark of Formosan Taxus mairei. The structures of 1-3 were identified as 5alpha,7beta,9alpha,13alpha,20-pentaacetoxy-2alpha,10beta,15-trihydroxy-11(15-->1)-abeo-taxene, 5alpha,7beta,9alpha,20-tetraacetoxy-2alpha,10beta,13alpha,15-tetrahydroxy-11(15-->1)-abeo-taxene, and 2alpha,4alpha,7beta,10beta-tetraacetoxy-5beta,20-epoxy-9alpha,13alpha,15-trihydroxy-11(15-->1)-abeo-taxene, respectively, on the basis of 2D NMR techniques including COSY, HSQC, HMBC, and NOESY experiments as well as chemical reactions of compounds 1-3 to give 4 (5alpha,7beta,9alpha,10beta,13alpha,20-hexaacetoxy-2alpha,15-dihydroxy-11(15-->1)-abeo-taxene) and 5 (4alpha,7beta,10beta-triacetoxy-9alpha,13alpha-dibenzoxy-5beta,20-epoxy-2alpha,15-dihydroxy-11(15-->1)-abeo-taxene), which are also novel taxane derivatives. Taxumairols U (1) and V (2) exhibited significant cytotoxicities against human hepatoma tumor cells, while taxumairol W (3) was inactive.

TNF-α increases sensitivity to LPS in chronically catheterized rats

Patients with severe trauma injury are transiently exposed to increased serum concentrations of tumor necrosis factor-α (TNF-α). These patients are susceptible to the development of multisystem organ failure (MSOF) triggered by subsequent exposure to bacterial toxins either via infection or increased intestinal permeability. We simulated the cytokine response of trauma by infusing 0.8 or 8.0 μg/kg of TNF-α (priming dose) into chronically catheterized rats. After 48 h, rats were challenged with endotoxin [lipopolysaccharide (LPS); 10 or 1,000 μg/kg]. Animals primed with either dose of TNF-α and then challenged with 1,000 μg/kg of LPS demonstrated significantly increased mortality, mean peak serum concentrations of interferon-γ (IFN-γ), and blood lactate concentrations ( P < 0.05) compared with nonprimed animals. Mean peak serum concentrations of IFN-γ and blood lactate concentrations were increased after challenge with 10 μg/kg of LPS only in animals primed with 8.0 μg/kg of TNF-α. Priming with TNF-α did not increase mortality after challenge with 10 μg/kg of LPS. These data suggest that both TNF-α release and the subsequent exposure to bacterial toxins mediate the pathophysiological progression from trauma to subsequent MSOF.

Five-color-based high-information-content fingerprinting of bacterial artificial chromosome clones using type IIS restriction endonucleases

We have developed a high-information-content fingerprinting (HICF) system for bacterial artificial chromosome (BAC) clones using a Type IIS restriction endonuclease, HgaI, paired with a Type II restriction endonuclease, RsaI. In the method described, unknown five-base overhangs generated with HgaI are partially or fully sequenced by modified fluorescent dideoxy terminators. Using an in-lane size standard labeled with a fifth dye, fragments are characterized by both the size and the sequence of its terminal one to five bases. The enhanced information content associated with this approach significantly increases the accuracy and efficiency of detecting shared fragments among BAC clones. We have compared data obtained from this method to predicted HICF patterns of 10 fully sequenced BACs. We have further applied HICF to 555 BAC clones to assemble contigs spanning 16p11.2 to 16p13.1 of human chromosome 16.

[Extraction and analysis of profenofos residue in tomato and cabbage by gas chromatography-flame photometric detector]

A quick and effective extraction and clean-up method of profenofos residue in tomato and cabbage is presented. Tomato and cabbage samples were homogenized with a mixture of acetone-hexane (1:1, V/V) using a mechanical homogenizer. The resultant homogenate was cleaned-up by adding active carbon and then filtered under reduced pressure. The filter cake was extracted twice with the same solvent mixture. The filtrates were combined and transferred into a separatory funnel. The organic layer was separated and evaporated to dryness using a rotary evaporator. The residue was dissolved in 2 mL of acetone and transferred into a small glass vial and then determined by GC on a 5% OV-101 Chromosorb W-HP column with flame photometric detector. The results showed that this analytical method can be used for an accurate determination of profenofos residues in tomato and cabbage. The minimum detectable concentration of profenofos in samples was 0.06 mg/kg. The recoveries of profenofos in tomato and cabbage were in the range of 96.2%-105.9% and 94.7%-102.3%, respectively. The relative standard deviations were in the range of 3.7%-4.9% and 3.7%-5.0%, respectively. The tomato and cabbage samples were collected 3 weeks after applying profenofos in the field, and the contents of profenofos were determined. The average contents of profenofos in tomato and cabbage were (13.8 +/- 0.8) mg/kg and (14.4 +/- 0.7) mg/kg, respectively.

Cloning, Mapping, and Characterization of the Human Sorbin and SH3 Domain Containing 1 (SORBS1) Gene: A Protein Associated with c-Abl during Insulin Signaling in the Hepatoma Cell Line Hep3B

SH3P12/CAP/ponsin, a gene product with a sorbin homology domain and three consecutive SH3 domains in the carboxy-terminus, has been isolated from murine adipocytes and identified as an important adaptor during insulin signaling. Here we describe the cloning, mapping, and expression of the human homologue, termed SORBS1 (sorbin and SH3 domain containing 1). Multiple transcripts of this gene with different mRNA isoforms were observed among different tissues. Here we report 13 alternatively spliced exons, which were ascertained from the full-length cDNA cloned in adipose, liver, and skeletal muscle tissues. Among the major isoforms, the shortest, 2223-bp, open reading frame (ORF) encodes a protein with a predicted molecular weight of 81.5 kDa, while the longest, 3879-bp, ORF encodes a protein of about 142.2 kDa. This gene was mapped to human chromosome 10q23.3-q24.1, which is a candidate region for insulin resistance found in Pima Indians. In human hepatoma Hep3B cells, SORBS1 was partly dissociated from the insulin receptor complex and bound to c-Abl protein upon insulin stimulation. This interaction with c-Abl was through the third SH3 domain and a possible conformational change of SORBS1 induced by insulin. Our data suggest that c-Abl oncoprotein via SORBS1 might play a role in the insulin signaling pathway.

Dynamic magnetic resonance imaging technique for the study of the temporomandibular joint

AIMS

Echo planar imaging (EPI) is an ultrafast magnetic resonance imaging (MRI) technique that can scan a single frame in less than a second. The aim of this study was to use the EPI technique to develop a new dynamic MRI protocol for the temporomandibular joint (TMJ).

METHODS

Basic fast-field echo and EPI pulse sequences were used for dynamic studies of the TMJ. The subjects were instructed to perform spontaneous, continuous, slow opening/closing movements without visual or audio feedback. Different scanning parameter settings were explored to optimize the results.

RESULTS

With an opening/closing movement of approximately 6 to 7 seconds per cycle, the proposed protocol yielded a good insight into the relative motion between condyle and disc. It was also possible to see the deformation of the disc during movement.

CONCLUSION

The EPI technique is a non-invasive technique that can be used for dynamic imaging study of a slow but continuous, uninterrupted jaw movement.

Individualized oblique-axial magnetic resonance imaging for improved visualization of mediolateral TMJ disc displacement

AIMS

A new individualized oblique-axial orientation of magnetic resonance imaging scans of the temporomandibular joint (TMJ), corrected to be perpendicular to the tangent of the posterior slope of the articular eminence, has been proposed to improve the representation of the disc. The aim of this study was to evaluate the quality of the images obtained with this new type of scanning plane and to assess the factors that can affect the scans.

METHODS

Twenty-nine TMJs were scanned by the use of sagittal, conventional coronal, and individualized oblique-axial scanning planes. On the sagittal images, the angle alpha between the tangent of the posterior slope of the articular eminence and the vertical was measured, and the disc position was evaluated. For both imaging planes, 2 examiners, blind to the scanning techniques, counted the number of conventional coronal and oblique-axial scans in which the disc was visible and in which the medial and lateral disc borders were well demarcated and evaluated the mediolateral disc position.

RESULTS

The individualized oblique-axial technique was superior to the conventional coronal technique in depicting the disc and its medial and lateral demarcations (paired t test, P < 0.05). The possibility of correct diagnosis of the mediolateral disc position and the agreement between the observers in this evaluation were better with the oblique-axial technique than with the conventional technique (P < 0.05). This was particularly evident when the disc was anteriorly displaced.

CONCLUSION

The individualized oblique-axial scanning planes should be used for a better representation of the disc/condyle complex mediolaterally if the disc is anteriorly displaced.

Predicting factors of malignancy in dermatomyositis and polymyositis: a case-control study

BACKGROUND

An association between dermatomyositis (DM)/polymyositis (PM) and malignancies has been widely reported in the literature. The validity of extensive evaluation for malignancies in those patients has also been questioned for decades. Only limited papers regarding the signs of malignancy and the prognostic factors in DM/PM have been reported.

OBJECTIVES

To define the potential risk factors of concomitant neoplastic diseases in patients diagnosed as having DM/PM.

METHODS

From 1 April 1983 to 30 June 1999, 147 patients were diagnosed as having probable or definite DM/PM at the Veterans General Hospital, Taichung, Taiwan. We excluded four patients who had preceding neoplastic diseases diagnosed before DM/PM, then retrospectively reviewed the data of the remaining 143 patients and subgrouped the cases as four main types: primary idiopathic DM, primary idiopathic PM, juvenile DM/PM and amyopathic DM (ADM). We next performed univariate analysis using logistic regression to evaluate the possible predictive factors for malignancies, such as mean age at onset, gender, manifestations at onset, association with other connective tissue diseases, initial skin presentations, complications and laboratory data. Then we chose the significant factors for multivariate analysis by logistic regression, to determine the independent risk factors of malignancies in DM/PM patients.

RESULTS

Among the 143 patients, DM was the most common type (64%), followed by ADM (14%), juvenile DM/PM (13%) and PM (10%). The mean age at onset overall was 42.4 years. Other connective tissue diseases were present in 22% of all patients, especially PM (50%) and juvenile DM/PM patients (28%). Internal malignancies were present in 13% of patients, and most were associated with DM. Nasopharyngeal carcinomas (NPCs) were the most common tumours. Patients with primary idiopathic DM, with an older age at onset, higher serum creatine phosphokinase levels and male gender, had more chance of developing concomitant malignancies. Those associated with complications, especially interstitial lung diseases, had a lower risk of associated neoplasia. In multivariate analysis, an older age at onset (odds ratio 9.10) and male gender (odds ratio 4.06) were associated with greater risk of developing malignancies.

CONCLUSIONS

The two independent predictive factors for malignancy (P < 0.05) in patients with DM/PM were an older age at onset (> 45 years) and male gender. The primary idiopathic DM group was shown to have higher risk of developing internal malignancies, especially NPC. However, this was not identified as an independent predictive factor for concomitant neoplastic diseases in multivariate analysis. In addition, patients who had the complication of interstitial lung disease had a significantly lower frequency of malignancies (P < 0.001).

Six new dammarane-type triterpene saponins from the leaves of Panax ginseng

Six new minor saponins, together with known ginsenosides, were isolated from the leaves of Panax ginseng. The new saponins were named as ginsenoside-Rh5, -Rh6, -Rh7 -Rh8, -Rh9 and -Rg7, and their structures were elucidated on the basis of chemical and physicochemical evidence to be as follows: ginsenoside-Rh5: 3beta,6alpha,12beta,24zeta-tetrahydroxy-dammar-20(22),25-diene 6-O-beta-D-glucopyranoside (1), -Rh6: 3beta,6alpha12beta,20(S)-tetrahydroxy-25-hydroperoxy-dammar-23-ene 20-O-beta-D-glucopyranoside (2), -Rh7: 3beta,7beta,12beta,20(S)-tetrahydroxy-dammar-5,24-diene 20-O-beta-D-glucopyranoside (3), -Rh8: 3beta,6alpha,20(S)-trihydroxy-dammar-24-ene-12-one 20-O-beta-D-glucopyranoside (4), -Rh9: 3beta,6alpha,20(S)-trihydroxy-12beta,23-epoxy-dammar-24-ene 20-O-beta-D-glucopyranoside (5) and -Rg7: 3-O-beta-D-glucopyranosyl 3beta,12beta,20(S),24(R)-tetrahydroxy-dammar-25-ene 20-O-beta-D-glucopyranoside (6).

An effective strategy of using molecular testing to screen mentally retarded individuals for fragile X syndrome

Fragile X syndrome (FXS) is the most common form of familial mental retardation (MR). It is caused by the expansion of the CGG repeat in the FMR1 gene on the X chromosome. To date, FXS is not treatable, but can be prevented by prenatal genetic examination. Identifying women who carry a full mutation or premutation FMR1 gene is thus very important, and can be done by tracing family members of FXS subjects. However, most of the FXS subjects in Taiwan as well as those in many other countries have not been identified. In this study the authors attempt to develop reliable and inexpensive tests suitable for a large-scale screen of subjects with MR for FXS. Together with their previous study, a total of 311 male and 160 female subjects with MR were screened with nonradioactive Southern blot assay using mixed deoxyribonucleic acid from three subjects of the same sex. From these subjects, nine male subjects and one female FXS subject were diagnosed. All male subjects were also screened with nonradioactive polymerase chain reaction (PCR). These nine male FXS subjects were also detected on the basis of PCR amplification failure. No false-negative results were discerned. The PCR procedure was simplified further by combining it with an analysis of a blood spot on filter paper, which is a much simpler and cheaper method for sample collection and DNA preparation. This method was then used to screen 104 boys with MR. Two of them were suspected, and later confirmed with Southern blot assay, as subjects with FXS. This study suggests that simple PCR combined with blood spot analysis could be a reliable, inexpensive test that is feasible for a large-scale screening of male subjects with MR for FXS. However, Southern blot assay with mixed deoxyribonucleic acid is appropriate for screening female subjects. Based on this strategy, most FXS subjects could be identified easily for further management.

Thrombin-stimulated growth, clustering, and collagen lattice contraction of human gingival fibroblasts is associated with its protease activity

BACKGROUND

Thrombin is a serine protease produced following gingival tissue injury or inflammation. It regulates the functional behavior of injury-neighboring cells via the activation of specific protease-activated receptors (PAR). Thrombin's role in gingival tissue healing and inflammatory response processes is not yet well understood.

METHODS

We investigated the effects of thrombin on gingival fibroblast (GF) growth [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay], collagen lattice contraction, and associated morphological changes.

RESULTS

Thrombin (>1 U/ml), but not thrombin receptor (PAR-1) agonist peptide (SFLLRN, single letter amino acid code, abbreviated as TRAP, 1 to 50 microg/ml), stimulated the growth and clustering of cultured human GF in vitro. Growth-stimulatory effects of thrombin were inhibited by D-Phe-Pro-ArgCH2Cl (PPACK), a serine protease inhibitor. By contrast, trypsin (>10 microg/ml), a PAR-2 activator, suppressed the growth of GF. Thrombin (>0.2 U/ml) and TRAP (10 to 25 microg/ml), but not trypsin, prostaglandin E2 (0.01 to 0.5 microg/ml), or bovine serum albumin (BSA) (1 to 80 microg/ml), induced the GF-populated collagen lattice contraction within 30 to 60 minutes of exposure. The thrombin-induced collagen lattice contraction was inhibited by PPACK (20 microg/ml) and an actin filament polymerization inhibitor, cytochalasin B (1 microg/ml). The collagen lattice contraction induced by TRAP was also inhibited by cytochalasin B, but not by PPACK. Using a reverse-transcriptase polymerase chain reaction (RT-PCR), the expression of PAR-1, and to a lesser extent PAR-3, was observed for human GF, although little PAR-2 and PAR-4 expression was noted.

CONCLUSIONS

These results indicate that thrombin is important in periodontal wound healing and inflammatory processes by promoting the growth and contraction of GF. The stimulatory effects of thrombin are associated with its protease activation of thrombin receptors.

[A study on the relationship between the changes of salivary EGF and oromaxillofacial tumors]

OBJECTIVE

To investigate the relationship between the changes of salivary epidermal growth factor (sEGF) concentration and oromaxillofacial tumors so as to find out its potential clinical value.

METHODS

The saliva of 123 patients with oromaxillofacial tumors,inflammations and precancerous lesions were measured for EGF concentration by radioimmunoassay (RIA) with the ligand(125)I-EGF and the saliva of 40 normal adults as the control.

RESULTS

Compared with the control, sEGF level of malignant,benign salivary gland tumors increased obviously;the former is higher than the latter significantly. The sEGF levels of patients with squamous cell carcinoma (SCC) of mucosa,recurrence and precancerous lesion were significantly higher than that of the control. There was no significant difference among the groups,but there was a tendency to increase by degrees. Compared with the control,the increase of the sEGF level of SCC patients with lymph node metastasis was of no significance. The sEGF level of oromaxillofacial inflammation was significantly higher than that of control.

CONCLUSION

The sEGF levels in patients with salivary gland tumor,SCC,inflammation increased in different degrees.

Effects of Nd:YAG laser irradiation on cultured human gingival fibroblasts

BACKGROUND AND OBJECTIVE

The Nd:YAG laser has been proposed to apply in minor soft tissue surgery, including various periodontal procedures. However, little information is available regarding the direct effect of Nd:YAG laser on gingival fibroblasts, which play an important role in the early healing processes of periodontal repair.

STUDY DESIGN/MATERIALS AND METHODS

Nd:YAG laser irradiation was performed in pulsed mode on human gingival fibroblasts, which was derived from healthy human gingiva by an explant method. The size of laser diode was 400 microm in diameter. The parameters in laser delivery were pulse energy (50-150 mJ), power output (1.0-3.0 W), pulse rate (10-30 pps), and fixed duration of irradiation (10 seconds). The cell cultures were analysed by cytomorphologic examination under phase-contrast and scanning electron microscope. The vitality was also examined with the help of MTT staining.

RESULTS

The area of laser damage on cell culture was circular in shape, with diameter beyond the size of laser diode. By scanning electron microscopy, we observed the cellular damage of cultured gingival fibroblasts induced by Nd:YAG laser irradiation, comparable with the progressive increased power settings. The cytomorphologic changes ranged from disappearance of cellular boundary, loss of identifiable cellular nucleus, and finally cell contraction and vacuolization. Significant decrease in cellular vitality (14% approximately 44%) after laser treatment with irradiation distance of nearly contact was noted. However, 2 mm defocusing irradiation with the same power settings did not significantly decrease cellular vitality.

CONCLUSION

Our study demonstrated the cell damaging effects of Nd:YAG laser, ranging from degeneratively cytomorphologic change to cell death, on the cultured human gingival fibroblasts. It provided the dentist a chance to understand the potential hazard of laser application in periodontal treatment. If the energy output is enough for the clinical purposes, Nd:YAG laser with lower pulse energy and corresponding pulse rate should be selected to minimize the damage on adjacent soft tissue.

Initial sequencing and analysis of the human genome

The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

The inhibitory effects of ginsenosides on protein tyrosine kinase activated by hypoxia/reoxygenation in cultured human umbilical vein endothelial cells

27 individual ginsenosides and aglycones, together with five extracts from ginseng roots, ginseng leaves, American ginseng roots, American ginseng leaves and non-saponin fraction from roots of Panax ginseng, were tested for their effects on protein tyrosine kinase (PTK) activation induced by an in vitro hypoxia/reoxygenation (H/R) model in cultured human umbilical vein endothelial cells (HUVEC). The results indicated that ginsenoside-Rb1 (3), -Rd (7), -Ra1 (1) and -Ro (27) showed significant inhibitory effects on PTK activation induced by H/R. Dose-response experiments revealed that ginsenoside-Rb1 was the most active compound and it completely blocked PTK activation at a wide range of concentrations. Most protopanaxadiol-type ginsenosides and some protopanaxatriol-type saponins also showed significant effects on PTK activation. However, the crude extracts did not protect against H/R-induced PTK activation.

The antioxidant caffeic acid phenethyl ester induces apoptosis associated with selective scavenging of hydrogen peroxide in human leukemic HL-60 cells

Caffeic acid phenethyl ester (CAPE), an active component of propolis, has many biological and pharmacological activities including antioxidation and tumor cell cytotoxicity. We examined the type of cell death in human leukemic HL-60 cells after CAPE treatment in order to elucidate the relationship between CAPE-induced alterations of the redox state and apoptosis. CAPE treatment (6 microg/ml) resulted in marked growth inhibition up to 70.3+/-4.0% at day 2. This inhibition was partially blocked by pretreatment with N-acetyl-L-cycteine (NAC). Agarose gel electrophoresis showed evident DNA fragmentation after CAPE treatment. CAPE induced a significant decrease in mitochondrial transmembrane potential to about half of the untreated level after 6 h and a rapid depletion of intracellular glutathione (GSH) down to 41.7+/-6.0% after 1 h. Pretreatment of HL-60 cells with NAC reversed the GSH depletion and partially rescued cells from CAPE-induced apoptosis. With regard to intracellular reactive oxygen species, CAPE caused a fast and profound scavenging of H202 (19% of untreated cells after a 2-h treatment) but not of superoxide anion. These results suggest that apoptosis induced by CAPE is associated with mitochondrial dysfunction, GSH depletion and selective scavenging of H2O2 in human leukemic HL-60 cells.

[Study on the expression of fibronectin after cerebral contusion in rats for timing of injuries]

An experimental model of reproducible focal cerebral contusions in rats was made by a free-drop impacting right hemisphere. The expression of fibronectin and its mRNA after cerebral contusion were detected respectively by immunohistochemical staining and in situ hybridization. Results indicated that the expression of fibronectin and its mRNA increased after injury, and there existed a relationship between increased fibronectin and its mRNA and different intervals after brain injury. It is inferred that the expression of fibronectin and its mRNA can be used for timing of brain injuries and distinguishing antemortem and postmortem brain contusions.

Characterization of the AdoMet-dependent guanylyltransferase activity that is associated with the N terminus of bamboo mosaic virus replicase

Bamboo mosaic virus (BaMV), a member of the potexvirus group, infects primarily members of the Bambusoideae. Open reading frame 1 (ORF1) of BaMV encodes a 155-kDa polypeptide that has long been postulated to be a replicase involved in the replication and formation of the cap structure at the 5' end of the viral genome. To identify and characterize the enzymatic activities associated with the N-terminal domain of the BaMV ORF1 protein, the intact replicase and two C-terminally truncated proteins were expressed in Saccharomyces cerevisiae. All three versions of BaMV ORF1 proteins could be radiolabeled by [alpha-(32)P]GTP, which is a characteristic of guanylyltransferase activity. The presence of S-adenosylmethionine (AdoMet) was essential for this enzymatic activity. Thin-layer chromatography analysis suggests that the radiolabeled moiety linked to the N-terminal domain of the BaMV ORF1 protein is m(7)GMP. The N-terminal domain also exhibited methyltransferase activity that catalyzes the transfer of the [(3)H]methyl group from AdoMet to GTP or guanylylimidodiphosphate. Therefore, during cap structure formation in BaMV, methylation of GTP may occur prior to transguanylation as for alphaviruses and brome mosaic virus. This study establishes the association of RNA capping activity with the N-terminal domain of the replicase of potexviruses and further supports the idea that the reaction sequence of RNA capping is conserved throughout the alphavirus-like superfamily of RNA viruses.

A pair of 24-hydroperoxyl epimeric dammarane saponins from flower-buds of Panax ginseng

Further investigation on the saponins of the flower-buds of Panax ginseng C. A. Meyer has resulted in the isolation and structural elucidation of a pair of new 24-epimers of dammarane type saponins named ginsenoside I and II. The structures of the epimers were characterized on the basis of chemical and spectral evidence as 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl]-20-S-O-beta-D-glucopyranosyl-3beta, 12beta,20(S)-trihydroxy-24xi-hydroperoxydammar-25-ene, except for their C-24 configurations. Ginsenoside I is a new triterpene glycoside, and ginsenoside II is a known compound first isolated from a natural plant.

Cyclic nucleotide phosphodiesterase type 5 activity limits blood flow to hypoperfused myocardium during exercise

BACKGROUND

Nitric oxide (NO) causes vasodilation by stimulation of guanylate cyclase in vascular smooth muscle to produce cGMP. The resultant vasodilator effect is regulated by a family of cGMP phosphodiesterases (PDEs). Sildenafil, a selective inhibitor of PDE5 used for treatment of erectile dysfunction, has been found to cause relaxation of isolated epicardial coronary artery segments. The present study examined the effects of sildenafil on coronary blood flow and hemodynamics during exercise in normal and ischemic heart.

METHODS AND RESULTS

In chronically instrumented normal dogs, sildenafil 2 mg/kg PO caused a slight but significant increase in left anterior descending (LAD) coronary blood flow during resting conditions, with a nonsignificant trend toward increased coronary flow during treadmill exercise. Exercise in the presence of LAD stenosis that decreased distal coronary pressure to 57+/-2 mm Hg reduced LAD flow during exercise from 69+/-8 to 41+/-7 mL/min (P:<0. 05), with hypoperfusion most severe in the subendocardium. At the same distal coronary pressure, sildenafil increased LAD flow in the ischemic region to 50+/-11 mL/min (P:<0.05). Increase in ischemic region blood flow produced by sildenafil was uniform across the LV wall, given that no change occurred in the transmural distribution of perfusion.

CONCLUSIONS

Inhibition of PDE5 with sildenafil caused vasodilation of coronary resistance vessels with an increase of blood flow into an ischemic myocardial region during exercise in the presence of coronary artery stenosis.

Loss of myocardial CK-MB into the circulation following 3.5 hours of swimming in a rat model

The purpose of this study was to document alterations of creatine kinase-B (CK-B) in the left and right ventricles of rats and CK-MB release into the circulation following a single bout of stressful prolonged intense exercise. Male Sprague-Dawley rats, with 8% bodyweight attached to each tail, were forced to swim 3.5 hours and were then sacrificed immediately (0 h PS), 3 hours (3 h PS), 24 hours (24 h PS), and 48 hours (48 h PS) post swimming, respectively. Sedentary (control) rats were sacrificed at rest. Serum CK-MB mass increased 2.1 times (8.9 microg/L; p < 0.01 vs. controls of 4.3 microg/L) and 1.4 times (6.0 microg/L; P < 0.01 vs. controls) at 0 h PS, and 3 h PS, respectively, and returned to baseline at 24 h PS. Western blot analysis indicated that CK-B of the right ventricle decreased 14% (p < 0.05), 20% (p < 0.01), and 12% (p < 0.05) at 3h PS, 24h PS and 48h PS, respectively. The CK-B of the left ventricles decreased 34% (p < 0.05) at 0 h PS, returned to baseline at 3 h PS, and was increased 39% (P < 0.01) at 48 h PS. Our findings demonstrate that a single bout of stressful, prolonged, intense exercise resulted in CK-B subunit loss from the myocardium, resulting in increased serum CK-MB concentrations, an indication of myocardial injury.

Comparison of anti-leukemic immunity against U937 cells in endurance athletes versus sedentary controls

To examine whether endurance athletes have higher anti-leukemic immunity than sedentary controls or not, we isolated peripheral blood mononuclear cells (MNC) from cyclists and sedentary controls to prepare conditioned media (CM) with various doses of phytohemagglutinin (PHA). The proliferation-inhibiting and differentiation-inducing activities of these PHA-MNC-CM on human leukemic U937 cells were investigated. Our results show that the growth inhibition activity of cyclists' PHA-MNC-CM were higher than that of controls. The dosage of PHA used to prepare MNC-CM to achieve about 90% growth inhibition was 5 microg/ml in the control group and was 2 microg/ml in the athletes group. The differentiation-inducing effects were evaluated by morphological scoring, superoxide production, and monocyte-associated antigen expression (CD14 and CD68). These three parameters all demonstrated the differentiation-inducing effect of MNC-CM increased with increasing dose of PHA. These effects were significantly greater in the athletic when compared to the sedentary control group at all doses of PHA. The levels of TNF-alpha and IFN-gamma PHA-MNC-CM increased in a PHA dose-dependent manner and were much higher in the athletic group when compared to the controls. We conclude that the capacity of endurance athletes to activate anti-leukemic immunity is significantly higher than that of sedentary controls.

Arrhythmogenic activity of cardiac muscle in pulmonary veins of the dog: implication for the genesis of atrial fibrillation

OBJECTIVE

Pulmonary veins are important foci of ectopic beats to initiate paroxysmal atrial fibrillation. The purpose of this study were to investigate the electrophysiological characteristics of excitable cells in canine pulmonary veins obtained from healthy and chronic rapid atrial pacing dogs and their responses to cardioactive agents.

METHODS

Transmembrane action potentials (APs) were recorded from multiple sites of pulmonary veins isolated from 17 healthy dogs and 14 dogs with chronic (6-8 weeks) rapid atrial pacing (780 bpm).

RESULTS

In normal superfusate, several types of electrical activities were identified, including silent electrical activity, fast response APs driven by electrical stimulation, and spontaneous fast or slow response APs (with or without early afterdepolarizations). The incidences of AP with an early afterdepolarization (93% versus 41%) was greater in chronic pacing dogs. The spontaneous activities were depressed by beta-adrenoceptor blocker, calcium channel blocker, adenosine and acetylcholine. High frequency (>8 Hz) irregular rhythms occurred spontaneously or were induced by cardioactive agents or electrical stimuli. The incidence of spontaneously occurring tachyarrhythmias was much higher in preparations from chronic pacing dogs (93%) than from control (12%). The tachyarrhythmias were suppressed by sodium channel blocker, potassium channel blocker or magnesium.

CONCLUSIONS

Pulmonary veins have arrhythmogenic ability through spontaneous activities or high-frequency irregular rhythms. The higher incidence of spontaneously occurring high-frequency irregular rhythms in chronic rapid atrial pacing dogs may account for the increased risk of atrial fibrillation in these dogs.

An analysis of meiotic pairing in trisomy 21 oocytes using fluorescent in situ hybridization

We report the use of chromosome 21-specific painting probes to analyze early stages of oogenesis in nine trisomy 21 fetuses. The proportion of cells in zygotene and pachytene in the trisomic ovaries ranged from 8 to 70% with a mean of 42% +/- 19 while the comparable values of euploid specimens ranged from 34 to 90% with a mean of 65% +/- 19. The low proportion of pairing cells may be the basis for the ovarian dysgenesis observed in some trisomy infants. Five percent of trisomic pachytene cells exhibited complete asynapsis which is an order of magnitude higher than that observed in euploid cells. A large fraction of the asynaptic cells were atretic which is consistent with the hypothesis of meiotic pairing as a signal for atresia. In addition, the asynaptic cells exhibited asynapsis of chromosomes other than 21, which we interpret as an interchromosomal effect of trisomy 21.

An increase in free radical production by means of an anion channel blocker DIDS in mouse peritoneal neutrophils

DIDS (4, 4'-diisothiocyanostilbene-2, 2'-disulfonic acid) has been recognized as an anion channel blocker. In this study, we demonstrated that DIDS significantly enhanced the production of free radicals in mouse peritoneal neutrophils. By means of a luminol-chemiluminescence (LCL) monitoring system, DIDS markedly increased LCL which could be suppressed by SOD, sodium azide (NaN3), EGTA and BAPTA-AM and only slightly inhibited by staurosporine (STP). Depletion of the endoplasmic reticulum (ER)-Ca2+ store by means of thapsigargin (TG) had no effects on DIDS-enhanced LCL, but DIDS significantly increased the amount of intracellular free calcium as monitored by means of fura-2 staining. These results indicate that DIDS may enhance free radical production mediated by Ca2+ release from the mitochondria. Both phorbol-12-myristate-13-acetate (PMA) and DIDS can induce increased translocation of p47-phox of the neutrophil to the membrane fraction, which is inhibited by STP pretreatment. Since free radical generation could reduce the cytoplasmic pH (pHi), we further examined whether DIDS was capable of inducing intracellular acidification. The result indicated that DIDS certainly lowered the pHi which was also suppressed by pretreatment with either NaN3 or NaCN, but not by diphenyleneiodonium (DPI). These findings lead us to propose a working hypothesis that DIDS mainly induces superoxide production accompanied by decreasing pHi mediated through a Ca2+ -dependent effect on the mitochondria rather than on NADPH oxidase. Using the lipophilic fluorescent dye DiOC6(3), we showed that DIDS decreased the transitional mitochondrial membrane potential. NaN3, but not STP or pyrrolidine dithiocarbamate (PDTC), antagonized DIDS in the course of decreasing the mitochondrial membrane potential. Taken together, all of these findings imply a possible role of anion channels of the mitochondria in modulating free radical production and intracellular acidification of neutrophils through alteration of the mitochondrial transition membrane potential and Ca2+ -release.

Comparison of landmark identification in traditional versus computer-aided digital cephalometry

The aim of this study was to assess landmark identification on digital images in comparison with those obtained from original radiographs. Ten cephalometric radiographs were selected randomly. Seven orthodontic residents identified 19 cephalometric landmarks on both the original radiographs and the digital images. To assess the concordance between landmarks identified on the original radiographs and on their digital counterparts, the x, y coordinates for each landmark in the 2 modalities were transformed with the identical references. The placement differences for 19 landmarks between 2 methods were calculated and their components in horizontal and vertical directions were analyzed respectively. Multivariate analysis of variance showed that the "cephalometric radiograph" and "landmark" variation had greater influence than that from "method" (landmark identification on digital / original radiograph). It was also noted that the differences of landmark identification between original radiographs and their digital counterparts were statistically significant. The landmarks with significant differences of horizontal component on the x-axis were Me, Gn, ANS, PNS, LIA. The differences were generally under 1 mm with the exception of Or, Me, PNS, LIA. The landmarks with significant differences of vertical component on the y-axis were Po, Or, Gn. The inter-observer error for each landmark in digital images was generally larger than that in the original radiographs. However, statistically significant differences of inter-observer errors between 2 modalities were only found for 4 of the 19 landmarks. These 4 landmarks, Po, Ar, ANS, and UM, should be scrutinized more carefully during potential applications of digital cephalometry.

A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension

AIMS

Stevioside is a natural plant glycoside isolated from the plant Stevia rebaudiana which has been commercialized as a sweetener in Japan for more than 20 years. Previous animal studies have shown that stevioside has an antihypertensive effect. This study was to designed to evaluate the effect of stevioside in human hypertension.

METHODS

A multicentre, randomized, double-blind, placebo-controlled study was undertaken. This study group consisted of 106 Chinese hypertensive subjects with diastolic blood pressure between 95 and 110 mmHg and ages ranging from 28 to 75 years with 60 subjects (men 34, women 26; mean +/- s.d., 54.1+/-3.8 years) allocated to active treatment and 46 (men 19, women 27; mean +/- s.d., 53.7+/-4.1 years) to placebo treatment. Each subject was given capsules containing stevioside (250 mg) or placebo thrice daily and followed-up at monthly intervals for 1 year.

RESULTS

After 3 months, the systolic and diastolic blood pressure of the stevioside group decreased significantly (systolic: 166.0+/-9.4-152.6+/-6.8 mmHg; diastolic: 104.7 +/- 5.2-90.3+/-3.6 mmHg, P<0.05), and the effect persisted during the whole year. Blood biochemistry parameters including lipid and glucose showed no significant changes. No significant adverse effect was observed and quality of life assessment showed no deterioration.

CONCLUSIONS

This study shows that oral stevioside is a well tolerated and effective modality that may be considered as an alternative or supplementary therapy for patients with hypertension.

Minimal-access surgery in managing osteoporotic vertebral fractures with neurological deficits: a preliminary report

BACKGROUND

Spinal cord compression as a result of osteoporotic vertebral fracture is very rare. Surgical decompression of this recognized complication is indicated when the patient has persistent neurological deficits. Clinically, these patients are usually elderly and in a generally debilitated state. Using formal anterior spinal surgery might significantly violate the patient's respiratory mechanism and increase operative mobidity or mortality.

METHODS

From January 1996 to June 1998, the authors used a minimal-access spinal approach to perform 1-stage decompressive corpectomy, interbody fusion, and internal fixation with a Reduction-Fixation titanium spinal plate (Trifix, San Leandro, CA, USA) by thoracoscopic assistance in 8 patients with osteoporotic vertebral fractures from T11 to L1, and neurological deficits. This involved a modified 2-portal technique that required a 2-cm wound in order to initially introduce the thoracoscope, and a minithoracotomy wound (usually 5-6 cm) for surgical manipulation.

RESULTS

None of the operations resulted in injury to the great vessels, internal organs, or spinal cord. The average followup period was 30 months (range, 22-50 months). Complications included 1 radiolucent line around a vertebral screw, 1 lateral migration of a vertebral screw with bone graft displacement, 1 transient incisional wound hypesthesia, and 1 iliac donor site pain. In the current patients, the average neurological recovery was 1.1 grades on the Frankel scale.

CONCLUSION

The authors advocate that such a minimal-access technique with thoracoscopic assistance presented in the current study is an ideal alternative in treating patients with osteoporotic vertebral fractures and neurological deficits. It can obviate the necessity of dividing the diaphragm in order to facilitate exposure; no patient in the current series required intensive care postoperatively. However, the stability of the vertebral screw purchase in the osteoporotic spine is a matter of concern.

[An analysis of ionic flow of spontaneous slow action potential of guinea pig aortic vestibule]

Spontaneous slow action potentials of aortic vestibule of isolated guinea pig heart were intracellularlly recorded. Electrophysiological parameters examined are: maximal diastolic potential (MDP), amplitude of action potential (APA), maximal rate of depolarization of phase 0 (V(max)), velocity of diastolic depolarization of phase 4 (VDD), duration of 50% and 90% repolarization (APD(50) and APD(90)) and rate of pacemaker firing (RPF). It was found that (1) 0.5 micromol/L nisoldipine (Nis) significantly decreased APA, V(max), VDD and RPF (P<0.01); (2) 1.2 mmol/L tetrodotoxin (TTX) significantly decreased APA and V(max) (P<0.05), but VDD and RPF were significantly slowed down as compared with control (P<0.01); (3) 2 mmol/L 4-aminopyridine (4-AP) elicited a decrease in MDP, APA and V(max) (P<0.01), but an increase in VDD and RPF (P<0.01); (4) when 1.5 mmol/L CsCl was perfused for 5 min, the VDD and RPF were significantly decreased (P<0.05); and (5) under the condition of hypoxia and perfusion with deprived glucose content for 15 min, the VDD and RPF were decreased (P<0.01). The above results suggest that (1) in addition to Ca(2+), Na(+) current contributes to generation of 0 phase of depolarization of slow response activity in aortic vestibule mainly, and (2) in addition to the inward Ca(2+) and Na(+) current and attenuated K(+) current, I(f) current also plays some role in phase 4 of depolarization.

Chromosomal changes and clonality relationship between primary and recurrent hepatocellular carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is highly malignant and prone to recur after surgical treatment. Differentiation between a true relapse of HCC and a second primary tumor is of clinical importance. However, no convenient method is currently available.

METHODS

Comparative genomic hybridization (CGH) was used to analyze 31 pairs of initial and recurrent HCC samples obtained from patients undergoing 2 consecutive surgeries. The resulting chromosomal aberration profiles were used as genomic fingerprints to determine tumor clonalities and their relationships.

RESULTS

Eleven recurrent tumors with high clonal relationship (CR) values (>0.95) were found to be relapsed HCCs, and 11 tumors with CR values close to 0 were found to be second primary HCCs. The other 9 paired samples had inconclusive CR values between 0.95 and 0.4. Two were confirmed by hepatitis B virus integration and X chromosome inactivation analysis to be de novo cancers (CR values, 0.35 and 0. 23, respectively). Initial HCCs that subsequently relapsed accumulated more chromosomal aberration events than those that developed de novo HCC (mean, 16.1 +/- 4.5 vs. 5.4 +/- 4.8 events; P < 0.01). Also, they more frequently showed gains on chromosome arms 3q, 6p, 8q, and 17q and losses on 4q and 16p.

CONCLUSIONS

CGH is useful for chromosomal aberration study and tumor clonality analysis. More and characteristic genomic changes in the initial HCC suggest that subsequent tumor recurrence is a true relapse.

[Molecular phylogeny of canidae using mitochondrial cytochrome b DNA sequences]

372 bp mitochondrial cytochrome b DNA of blue fox, red fox, raccoon dog, and wolf were sequenced. Combined with the DNA fragments of dog, simien fox, and African wild dog, sequences were aligned and analyzed. There are 113 nucleotide sites substituted (30%). Molecular phylogenetic tree constructed by NJ method suggests that African wild dog is the earliest divergent. Wolf, dog, and simien fox which belong to genus Canis are combined into one branch which diverged earlier than raccoon dog, red fox and blue fox. Red fox is more related to blue fox than the other animals. The above result is in consistent with that of morphology.

Septic arthritis of the ankle joint

BACKGROUND

Septic arthritis of the ankle joint is a rare but serious disease. Very few reports in the literature have mentioned the method of care and treatment results of septic ankle. This study was designed to retrospectively review the treatment results and to analyze the prognostic factors of septic arthritis of the ankle inpatients at our hospital. We also formulated a protocol for the management of septic arthritis of the ankle joint.

METHODS

All records of those patients with a diagnosis of septic ankle from 1985 to 1997 were retrospectively reviewed. There were 29 patients that met the diagnostic criteria of septic arthritis of the ankle joint (21 male and 8 female patients; 6 children and 23 adults). The average follow-up time was 5.5 years (ranging from 1.5 to 13.7 years). The patients' ages, associated diseases, single or multiple joint(s) involved, timing of treatment, and the final results of these cases were assessed. The infecting organism and drug sensitivity were discussed to determine the proper antibiotics regimen.

RESULTS

Staphylococcus aureus was the most common infecting microorganism in the septic ankles. Combined therapy with oxacillin and gentamicine was effective against 88.1% of the infecting microorganisms. The poor prognostic factors for septic ankle included a positive bacterial culture, involvement of multiple joints simultaneously, a delay in treatment, and an increased number of associated diseases. In addition, a high proportion of patients with septic ankle had gouty arthritis (43.5%).

CONCLUSION

Early treatment (symptom duration of less than 5 days) significantly affected the final results. The early recognition and prompt treatment of this condition may reduce morbidity and mortality. Based on our results, oxacillin and gentamicine are recommended as the first-line antibiotics for the management of septic ankle.

Antioxidant activity of polyphenols from seeds of Vitis amurensis in vitro

AIM

To study the antioxidant action of five polyphenols (+) catechin, procyanidin B2, procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin isolated from the seeds of Vitis amurensis.

METHODS

The mouse liver homogenate lipid peroxidation assay was applied for the evaluation of the antioxidant activity in vitro.

RESULTS

(+) Catechin, procyanidin B2, procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin showed antioxidant activity with the IC50 values of 0.47, 0.25, 0.10, 0.02, and 0.03 mmol/L, respectively. The IC50 value of vitamin E used as a positive control was 0.13 mmol/L. The structural activity relationship was also analyzed. Procyanidins carrying a galloyl group possessed higher anti-lipid peroxidation activities. All dimers were found to be more potent than the non-galloylated momomer such as (+) catechin. However, the activity of the 4-->6 linked dimer seemed more preferable than 4-->8 linked dimer.

CONCLUSION

Procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin showed a more antioxidant activity than vitamin E did, and their activity is dependent on their substitution and polymerization patterns.

Atrial tachycardias originating from the atrial septum: electrophysiologic characteristics and radiofrequency ablation

INTRODUCTION

The characteristics of atrial tachycardia (AT) have varied widely among different reports. The anatomic locations of ATs may bias the results. We propose that septal ATs and free-wall ATs have different characteristics.

METHODS AND RESULTS

One hundred forty-one patients with AT underwent electropharmacologic study, endocardial mapping, and radiofrequency ablation. Forty-nine (34.7%) patients had septal AT originating from the anteroseptal, mid-septal, and posteroseptal areas. Tachycardia cycle length was similar between septal AT and free-wall AT (367 +/- 46 msec vs 366 +/- 58 msec, P > 0.05). More patients with septal AT required isoproterenol to facilitate induction (44.9% vs 31.5%, P <.0.05). Septal AT was more sensitive to adenosine than free-wall AT (84.4% vs 67.8%, P < 0.05). Only posteroseptal AT showed a positive P wave in lead V1 and negative P wave in all the inferior leads (II, III, aVF). Radiofrequency catheter ablation had a comparable success rate for septal AT and free-wall AT (96% vs 95%) without impairment of AV conduction. During follow-up of 49 +/- 13 months (range 17 to 85), the recurrence rate was similar for septal AT and free-wall AT (3.2% vs 4.6%, P = 0.08).

CONCLUSION

Septal AT has electrophysiologic characteristics that are distinct from those of free-wall AT. Catheter ablation of the septal AT is safe and effective.

Orificial tuberculosis and Kaposi's sarcoma in an HIV-negative individual

Orificial tuberculosis is a rare form of cutaneous tuberculosis. It happens mainly in immunocompromised patients and is characterized by rapidly ulcerating papules in the orifices, including oropharynx or anus, due to autoinoculation of internal tuberculosis. It is a symptom of advanced underlying disease. Kaposi's sarcoma occurs more frequently with the increase of HIV-infected patients. We report on an HIV-negative individual who developed rapid-deteriorating orificial tuberculosis concomitant with Kaposi's sarcoma and had a fatal outcome.

Subject-domain approach to the study of air pollution effects on schoolchildren's illness absence

In this paper, the authors propose a new statistical modeling technique, the subject-domain approach, which is theoretically proven to be equivalent to the time-domain approach in detecting an association between exposure and response with time trends. The authors use an empirical data set from a school absence monitoring study conducted during the 1994-1995 school year in Taiwan to demonstrate this subject-domain approach's application to environmental epidemiologic studies. Because the subject-domain models can control the influential personal confounding factors in the models, they show greater statistical power than the traditional time-domain approaches in determining the relation between air pollution and illness absences. The authors' models found that the schoolchildren's risks of illness absence were significantly related to acute exposures to nitrogen dioxide and nitrogen oxides with a 1-day lag (p < 0.01) at levels below the World Health Organization's guidelines. By contrast, the authors could not detect significant associations between air pollution and schoolchildren's absenteeism using time-domain approaches. Such findings imply that the models built on subject domain may be a general solution to the problem of the ecologic fallacy, which is commonly encountered in environmental and social epidemiologic studies.

Changes in superoxide dismutase activity and mRNA in vivo after short-term supplementation with trilinolein in rats

BACKGROUND

Oxidative damage plays a central role in atherogenesis and antioxidation defense mechanisms may prevent atherosclerosis. This study evaluated the effect of short-term supplementation of the natural lipophilic antioxidant trilinolein on superoxide dismutase (SOD) activity and SOD-mRNA gene expression in vivo in rat vital organs.

METHODS

Male Wistar rats (n = 8) were injected intraperitoneally with trilinolein (1 mM/ml/kg/day in 0.5% ethanol) daily for three consecutive days. Two control groups (n = 8) were administered saline or 0.5% ethanol in saline, respectively, for three days.

RESULTS

Assay of SOD activity and SOD-mRNA by Northern blotting in rat liver, spleen and brain showed significant increases in SOD activity and increased SOD-mRNA gene expression.

CONCLUSIONS

The natural lipophilic antioxidant trilinolein potentiates the SOD antioxidation defense mechanism and increases gene expression of SOD-mRNA after short-term supplementation in rats.

Dependence of electrogram duration in right posteroseptal atrium and atrium-pulmonary vein junction on pacing site: mechanism and implications regarding atrioventricular nodal reentrant tachycardia and paroxysmal atrial fibrillation

INTRODUCTION

The fractionated atrial electrogram, a signal helpful in identifying the target site for radiofrequency catheter ablation of the slow AV nodal pathway, is considered to arise from nonuniform anisotropic electrical activity. However, the effects of pacing sites and radiofrequency ablation on these electrograms are not clear. Similarly, the nature of the fractionated atrial electrogram in the atrium-pulmonary vein junction has yet to be determined.

METHODS AND RESULTS

Two experiments were performed in this study. Experiment 1 evaluated the fractionated atrial electrogram at target sites before and after slow AV nodal pathway ablation during sinus rhythm or during pacing from different sites. Group 1A consisted of 16 patients with dual AV nodal pathway physiology and AV nodal reentrant tachycardia who underwent successful ablation without residual slow AV nodal pathway. Group 1B consisted of 7 patients who underwent successful elimination of AV nodal reentry but with residual dual AV nodal pathway physiology. Group 1C consisted of 6 patients who still had AV nodal reentrant tachycardia after two applications of radiofrequency energy. In group 1D, there were 16 patients with dual AV nodal pathway physiology, but without inducible AV nodal reentrant tachycardia. In group 1E, there were 15 patients without dual AV nodal pathway physiology. Experiment 2 investigated the fractionated atrial electrogram in the ostium of the left and right superior pulmonary veins in 18 patients with paroxysmal atrial fibrillation (2A) and in 8 patients without paroxysmal atrial fibrillation (2B). Before radiofrequency ablation, electrogram duration in the right posteroseptal atrium during pacing from the middle coronary sinus or the right posterolateral atrium was shorter than that during pacing from the high right atrium (HRA) in all group 1 patients. After the successful elimination of the slow AV nodal pathway conduction in group 1A, atrial electrogram duration during HRA pacing was shorter than that before ablation. In experiment 2 patients, electrogram duration during pacing from the proximal or distal coronary sinus was shorter than that during pacing from HRA or sinus rhythm.

CONCLUSION

These findings suggest that the fractionated atrial electrograms in the right posteroseptal atrium and ostium of left or right superior pulmonary veins are potentially consistent with nonuniform anisotropic propagation. Alternations of electrogram characteristics after successful radiofrequency ablation of the slow AV nodal pathway may arise from the changes of nonuniform anisotropic activity in the right posteroseptal atrium.

[The expression of splicing fibronectin variants of cutaneous injuries in rats]

In situ hybridization with Digoxingenin labeled probes were used to build the relationship between incised cutaneous wounding intervals and the expression of splicing fibronectin variants (total, E III A and E III B Variants) in rats. The results showed that all forms of FN variants increased notably with the wounding time going on. E III A and E III B Variants were expressed abundantly 30 and 60 minutes after injury, while few in normal skin.

[The foundation of the injury model on cultured human fetal lung fibroblasts and its immunohistochemistry research]

Cultured human fetal lung Fbs was first used to study the relationship between wound age and the change of cFn synthesized by Fbs in Vitro. A sterilized injector was applied to scrap the cultured confluent Fbs and a "wound" was obtained. Fbs around the wound was seen to change from a stationary stage to an active stage. Using the method of immunochemistry and image analysis system (IAS), cFn synthesized by Fbs around the wound was observed at once, 30 min, 1 h, 3 h and 6 h after injury. It was found that cFn began to change 1 h after injury and increased continually within 6 h. It suggests that the change of cFn synthesized by Fbs is time-dependent after injury and this approach breaks a new path in the study on estimation of wound age.

Genomic characterization of the human heterotrimeric G protein alpha, beta, and gamma subunit genes

Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins. Each subunit of the G protein complex is encoded by a member of one of three corresponding gene families. Currently, 16 different members of the alpha subunit family, 5 different members of the beta subunit family, and 11 different members of the gamma subunit family have been described in mammals. Here we have identified and characterized Bacterial Artificial Chromosomes (BACs) containing the human homologs of each of the alpha, beta, and gamma subunit genes as well as a G alpha11 pseudogene and a previously undiscovered G gamma5-like gene. The gene structure and chromosome location of each gene was determined, as were the orientations of paired genes. These results provide greater insight into the evolution and functional diversity of the mammalian G protein subunit genes.

Ventricular tachycardia in a patient with primary hyperparathyroidism

We present a case of primary hyperparathyroidism with hypercalcemia in a patient who had spontaneous attacks of ventricular tachycardia. Right ventricular burst pacing reproducibly induced ventricular tachycardia in the electrophysiological laboratory after intravenous administration of calcium-gluconate, and verapamil could terminate the tachycardia. After resection of the parathyroid adenoma, the calcium level was restored to normal, and ventricular tachycardia did not occur again during the follow-up period.

Procyanidins from the seeds of Vitis amurensis

Three procyanidins, procyanidin B-5 3'-O-gallate, vitisinol, and amurensisin, were isolated from the seeds of Vitis amurensis, whose structures were elucidated on the basis of spectral and chemical evidence. Vitisinol and amurensisin contain a spiro-type biflavanyl linkage and a biphenyl-lactone partial structure, respectively.

Alkaloids and phenylpropanoids from Peganum nigellastrum

Two canthin-6-one alkaloids, luotonins C and D, and two phenylpropanoids, dihydrosinapyl ferulate and dihydroconiferyl ferulate, were isolated from the aerial parts of Peganum nigellastrum along with four known alkaloids, harmine, 3-phenylquinoline, 3-(4-hydroxyphenyl)quinoline and 3-(1H-indol-3-yl)quinoline. Their structures were elucidated by spectroscopic techniques. The structures of luotonins C and D were also confirmed by chemical synthesis.