Bisdemethoxycurcumin-mediated Attenuation of Apoptosis Prevents Gentamicin-induced Ototoxicity in Mouse Cochlear UB/OC-2 Cells

BACKGROUND/AIM

Gentamicin has been widely prescribed since the last two decades despite its ototoxicity and nephrotoxicity. Bisdemethoxycurcumin (BDMC) is an affordable and safe curcuminoid with medicinal properties. We aimed to understand the effects of BDMC on the gentamicin-induced hair cell damage in mouse cochlear UB/OC-2 cells, in order to elucidate the therapeutic potential of BDMC against gentamicin-induced ototoxicity.

MATERIALS AND METHODS

We quantified the cell membrane potential and examined the regulators and cascade proteins in the intrinsic pathway of hair cell apoptosis. Mouse cochlear UB/OC-2 cells were treated with BDMC before exposure to gentamicin. The effects of BDMC on hair cell viability, mitochondrial function, and apoptosis-related proteins were examined by flow cytometry, western blot, and fluorescent staining.

RESULTS

Our results revealed that BDMC reversed gentamicin-mediated cycle arrest at the G₂/M phase, stabilizing the mitochondrial membrane potential, decreasing cleaved caspase proteins, and successfully reversing hair cell apoptosis.

CONCLUSION

BDMC is a potential agent for reducing gentamicin-induced ototoxicity.

Unexpected complication of attempted epidural anaesthesia: cauda equina syndrome

Cauda equina syndrome after regional anaesthesia is a serious and devastating complication. Its occurrence after epidural anaesthesia is rare. We report a 46-year-old male who received epidural anaesthesia for ureterorenoscopic lithotripsy and developed cauda equina syndrome postoperatively. Despite one failed attempt at entering the epidural space with an epidural needle resulting in dural puncture, an epidural catheter was inserted and 20 ml pH adjusted lignocaine 2% with 1:200,000 adrenaline injected via the catheter without untoward event. The possible causes of this complication are discussed. Fortunately, this patient recovered almost completely ten months later.

DNA adduct formation and DNA strand breaks in green-lipped mussels (Perna viridis) exposed to benzo[a]pyrene: dose- and time-dependent relationships

Green-lipped mussels, Perna viridis, were exposed to 0, 0.3, 3 and 30 micrograms l-1 (nominal concentrations) B[a]P under laboratory conditions over a period of 24 days. Mussels were collected on day 0, 1, 3, 6, 12, 18 and 24, and the levels of DNA adducts and DNA strand breaks in their hepatopancreas tissues monitored. Mussels exposed to 0.3 and 3 micrograms l-1 B[a]P showed marked increases in strand breaks after 1 day of exposure. DNA strand break levels in these mussels remained high and significantly different from the control values until day 3 for the 0.3 microgram l-1 treatment group, and day 6 for the 3 micrograms l-1 treatment group. This was followed by a gradual reduction in strand breaks. After 12 days, the levels of both groups had returned to the same level as that of the control. No increase in DNA strand breaks was observable in mussels exposed to 30 micrograms l-1 B[a]P in the first 12 days of exposure, but a significant increase was observed from day 12 to day 24. Increasing B[a]P concentrations resulted in elevated DNA adduct levels after 3-6 days of exposure, but this pattern of dose-related increase disappeared after 12 days. These results indicate that a better understanding of the complex interactions between exposure levels and durations is crucially important before DNA adduct levels and DNA strand breaks in P. viridis can be used as effective biomarkers for monitoring genotoxicants in marine waters.

[Protective effect of schisanhenol (SAL) on oxygen free radical induced injury of spleen lymphocytes in mice]

In the present paper the effects of Sal, an active component isolated from Kadsura Longipenduculata Finet et Gagnep, on oxygen free radical induced injury of murine spleen lymphocytes in vitro and in vivo were investigated. The results showed that Sal at 1 x 10(-4) mol.L-1 significantly inhibited the decrease of GSH content induced by Fe(2+)-Vit C and the increase of MDA formation induced by Fe(2+)-Cys in murine spleen lymphocytes. The decrease of membrane fluidity of lymphocytes under lipid peroxidation induced by Fe(2+)-Vit C was prevented by Sal. The damage of the lymphocyte surfaces induced by Fe(2+)-Vit C was also markedly reduced by Sal. Administration of Sal 20 mg.kg-1.d-1 for 8 d significantly increased the GSH content of the spleen lymphocytes in mice under high oxygen-stress. Meanwhile, the compensative increase of SOD activity in the spleen lymphocytes was reversed. The results suggest that Sal may protect murine spleen lymphocytes from the injury induced by oxygen free radicals.

Modeling elastic wave forward propagation and reflection using the complex screen method

Formulation for calculating forward propagation and reflection in a 3D elastic structure based on the complex-screen method is given in this paper. The calculation of reflections is formulated based on the local Born approximation. When using a small angle approximation, the backscattering operator reduces to a screen operator which is similar to the forward screen propagator. Combining the forward propagator and backscattering operator together, the new method can properly handle the multiple forward scattering and single backscattering in a 3D heterogeneous model. Using a dual-domain technique, the new method is highly efficient in CPU time and memory savings. For models where reverberation and resonance scattering can be neglected, this method provides a fast and accurate algorithm. Synthetic seismograms for two-dimensional elastic models are calculated with this method and compared with those generated by the finite-difference method. The results show that the method works well for small to medium scattering angles and medium velocity contrasts.

The sleeper Bostrichthys sinensis (family Eleotridae) stores glutamine and reduces ammonia production during aerial exposure

Bostrichthys sinensis inhabits brackish water, living in the crevices of the river mouths of Shang Xi and Guangdong, China. In its natural habitat, it may encounter aerial exposure frequently during low tides, and it usually remains quiescent in the absence of water. Upon aerial exposure in the laboratory, the ammonia excretion rate decreased to one-fourth that of the submerged control. Although all the enzymes of the ornithine-urea cycle were detected in the liver of this fish, the activity of hepatic carbamoyl phosphate synthetase was too low for the cycle to be functioning. Indeed, ammonia accumulated in the tissues and was not converted to urea. Results indicate that ammonia produced through amino acid catabolism was detoxified to glutamine during the first 24 h of aerial exposure. The excess amount of glutamine stored in the muscle during this period couldaccount approximately for the reduction in ammonia equivalent excreted. There was indeed a significant increase in the activity of glutamine synthetase from the liver of specimens exposed to terrestrial conditions. In contrast to the production of alanine, formation of glutamine is energetically expensive. Since B. sinensis remained relatively inactive on land, the reduction in energy demand for muscular activity might provide it with the opportunity to exploit glutamine formation as a means to detoxify ammonia. After 72 h of aerial exposure, B. sinensis reduced internal ammonia production, possibly through reductions in proteolysis and amino acid catabolism, to avoid excessive accumulation of ammonia.

Preparation of pentachlorophenol derivatives and development of a microparticle-based on-site immunoassay for the detection of PCP in soil samples

Pentachlorophenol (PCP) is used as a herbicide in agriculture and as an insecticide for termite control. Because of the apparent hazard associated with its usage, there is a need for an efficient and economic on-site screening method. A 5-min on-site test has been developed for the detection of PCP based on the OnTrak format, a successful Roche on-site test format for drugs of abuse, utilizing the principle of latex agglutination immunoassay. The test detects 1 ppm of PCP in soil samples.

The use of microangiography in detecting aberrant vasculature in zebrafish embryos exposed to cadmium

Embryonic vascular patterns in zebrafish (Danio rerio) could be visualised by confocal microscopy coupled with microinjected fluorescent microbeads. This microangiographic technique was adopted here, for the first time, to study the effects of cadmium on cardiovascular development in zebrafish embryos. Zebrafish embryos were incubated in culture medium containing 100 microM cadmium from 5 h post fertilisation (hpf) to 48 hpf. At 48 hpf, embryos were examined for viability and occurrence of malformations. The 100 microM cadmium caused 32.21 +/- 3.65% mortality and 20.33 +/- 4.04% visible malformations in surviving embryos. In the remaining embryos with no visible signs of malformations, further assessments for less obvious abnormalities were performed. Assessments on craniofacial development were made by digital measurements on areas of brains and eyes. Cardiac development was assessed by immunostaining the heart with the antibody MF20 specific for myosin heavy chain. Body lengths of the embryos were also measured. Embryonic development of brains, eyes, hearts and body lengths of visibly healthy embryos in the cadmium treatment group showed no significant difference from the controls. Embryonic vasculature of these visibly healthy embryos was then studied by microinjecting fluorescent microbeads of diameter 0.02 microm into the circulation. All the cadmium treated embryos showed localised vascular defects in the dorsal aortae, segmental and cranial vessels while none of the control embryos showed any aberrant patterns in the networking of the vasculature. Improved image analyses on the anterior regions revealed that cadmium treated embryos had markedly less complex networks of cranial vessels with fewer vessels perfusing the craniofacial regions. The number of branch points in the vascular network was counted. In untreated embryos, there were 135.6 +/- 51 branches in the vasculature in entire body. In the cadmium treated embryos, there were 64.5+/-31 branches. The difference was significant when assessed with Student's t-test. It appeared that although cadmium did not cause any signs of external malformations in these visibly healthy embryos, nonetheless induced impaired branching and anastomsis of the cranial vessels. This study revealed, for the first time, that vital vascular structures in fish embryos could be affected by exposure to cadmium. This technique allowed visualisation of vascular anomalies in embryos showing no external signs of malformations. The impairment of anatomical features during embryonic development might serve as meaningful health endpoints in ecotoxicological studies and in risk assessment.

Bioenergetics and RNA/DNA ratios in the common carp (Cyprinus carpio) under hypoxia

Hypoxia caused by eutrophication occurs over large areas in aquatic systems worldwide. Common carp (Cyprinus carpio) exposed to hypoxia (1 mg.O2.l(-1) and 2 mg.O2.l(-1)) for 1 week showed a significant reduction in feeding rate, respiration rate, faecal production and nitrogenous excretion compared to those maintained at normoxia (7 mg.O2.l(-1)). Fish exposed to hypoxia showed negative scope for growth (SfG), but no significant difference in the specific growth rate was revealed after 1 week in both hypoxic groups. A significant reduction in RNA/DNA ratio was, however, clearly evident in the white muscle of the 1 mg.O2.l(-1) treatment group, but not in the 2 mg.O2.l(-1) treatment group. Both specific growth rate and RNA/DNA ratio were significantly reduced when fish were exposed to severe hypoxia (0.5 mg.O2.l(-1)) for 4 weeks. At all levels of hypoxia, growth reduction was accompanied by a significant decrease in RNA/DNA ratio in white muscle. Covariance analysis showed no significant difference between the slope of RNA/DNA ratio and growth rate under normoxic conditions and 0.5 mg. O2.l(-1) for 4 weeks (F= 1.036, P > 0.326), as well as 1.0 mg.O2.l(-1) and 2.0 mg.O2.l(-1) for 1 week (F = 0.457, P > 0.5), indicating that the RNA/DNA ratio serves as a biomarker of growth under all oxygen levels, at least under controlled experimental conditions. SfG also appears to be more sensitive than the RNA/DNA ratio in responding to hypoxia in fish.

Invasion and metastasis of a mammary tumor involves TGF-beta signaling

Several studies have correlated escape from TGF-beta-mediated cell cycle arrest with the tumorigenic phenotype. Most often, this escape from growth control has been linked to dysfunctional TGF-beta receptors or defects in the TGF-beta-mediated SMAD signaling pathway. In this report, we found that highly metastatic 4T1 mammary carcinoma cells express functional TGF-beta receptors capable of initiating SMAD-mediated transcription, yet are not growth inhibited by TGF-beta1. We further observed that TGF-beta directly contributes to the metastatic behavior of this cell line. Exposure to TGF-beta caused 4T1 cells to undergo morphological changes associated with the metastatic phenotype and invade more readily through collagen coated matrices. Furthermore, expression of a dominant negative truncated type II receptor diminished TGF-beta signaling and significantly restricted the ability of 4T1 cells to establish distant metastases. Our results suggest that regardless of 4T1 resistance to TGF-beta-mediated growth inhibition, TGF-beta signaling is required for tumor invasion and metastases formation.

Reproductive impairment of sea urchin upon chronic exposure to cadmium. Part II: Effects on sperm development

Chronic pollution may impair the reproductive success of adult organisms through a decrease in the quality of gametes. Our parallel study on gamete quality, showed that male sea urchins were more sensitive than the females towards cadmium pollution. The effects of chronic exposure to 0.01 and 1 ppm Cd2+ on sperm development of the sea urchin Anthocidaris crassispina were studied. Despite the fact that no significant change in gonad index was observed when sea urchins were exposed to both levels of Cd2+ for 4 weeks, deposition of electron-dense materials was conspicuous at the wall and intracellular space of male gonads. Apparent cytological alterations were observed in sperm cells, including changes in morphology of nuage in spermatogonia. The discrete, granular bodies of nuage were replaced by a large electron-dense body. Spermatozoa with short, incomplete 'broken' tails (scanning electron microscope observation) or tails of spermatids/spermatozoa with extraordinary electron-density (transmission electron microscope observation) were more abundant in gonads exposed to both levels of Cd2+. Mitochondrial cristae deformation was observed for sperm cells at all stages of development. Sperm plasma membrane also became more convoluted but acrosome remained intact. The observed cytological distortion of sperm tails and mitochondria/midpiece could help to explain the decline in motility as well as poor perseverance in sperm produced by sea urchins exposed to cadmium observed in our earlier study.

A field study on EROD activity and quantitative hepatocytological changes in an immature demersal fish

Demersal fish, Solea ovata, were sampled from a reference site and a site where highly contaminated sediment is dumped. Sexually immature fish from the contaminated site exhibited significantly higher EROD activity compared with counterparts sampled from the reference site. No significant difference in EROD activity could be found for sexually mature males and females between sites. The relationship between EROD activity and quantitative changes in hepatic lipofuscin/ceroid, as well as peroxisome, was investigated for immature S. ovata. A significant correlation was found between EROD activity and volume density of lipofuscin/ceroid in fish hepatocyte (r = 0.750; P < 0.05), but no significant correlation was discernible between EROD activity and peroxisomes. Results from this field study corroborate our earlier laboratory findings, in which induction of EROD activity by intraperitoneal injection of benzo[a]pyrene was associated with increase in absolute volume and absolute number of lipofuscin/ceroid in hepatocytes. The present study provides further evidence that induction of EROD activity is associated with an increase in hepatic lipofuscin/ceroid and possibly cytological damages in immature S. ovata. This cytological change may serve as a potential marker for exposure to PAHs and PCBs.

Invasion and metastasis of a mammary tumor involves TGF-beta signaling

Several studies have correlated escape from TGF-beta-mediated cell cycle arrest with the tumorigenic phenotype. Most often, this escape from growth control has been linked to dysfunctional TGF-beta receptors or defects in the TGF-beta-mediated SMAD signaling pathway. In this report, we found that highly metastatic 4T1 mammary carcinoma cells express functional TGF-beta receptors capable of initiating SMAD-mediated transcription, yet are not growth inhibited by TGF-beta1. We further observed that TGF-beta directly contributes to the metastatic behavior of this cell line. Exposure to TGF-beta caused 4T1 cells to undergo morphological changes associated with the metastatic phenotype and invade more readily through collagen coated matrices. Furthermore, expression of a dominant negative truncated type II receptor diminished TGF-beta signaling and significantly restricted the ability of 4T1 cells to establish distant metastases. Our results suggest that regardless of 4T1 resistance to TGF-beta-mediated growth inhibition, TGF-beta signaling is required for tumor invasion and metastases formation.

Reproductive impairment of sea urchins upon chronic exposure to cadmium. Part I: Effects on gamete quality

Successful reproduction is a determining factor for species survival. Pollution may impair reproductive success of adults through effects on gamete quality. Reproductive impairment of the sea urchin Anthocidaris crassispina upon chronic (4 weeks) exposure to 0.01 and 0.1 mg l-1 Cd2+ was investigated. Criteria used for assessing gamete quality included sperm motility, egg morphology, fertilization rate and dynamics of first cleavage. A dose-response relationship was found between Cd2+ levels and changes in sperm motility, and percentage fertilization. Sperm motility, measured by computer-assisted sperm analysis, indicated that percent motile sperm, velocities, and percent sperm with normal trajectory were significantly affected by chronic exposure to > or = 0.1 mg l-1 Cd2+. A decline in sperm motility was also accompanied by a decrease in fertilization success of sea urchin sperm. Width/height ratio of sea urchin eggs was not affected by cadmium, but larger egg sizes were found when sea urchins were exposed to 0.1 mg l-1 Cd2+. Male sea urchins exposed to Cd2+ produced poorer quality sperm, as indicated by a lower percent fertilization and lower cleavage rate, implying that male sea urchins were more sensitive than females to chronic Cd2+ exposure. Results of the present study provide an explanation of reproductive impairment in marine invertebrates upon chronic exposure to Cd2+.

Tetracationic porphyrins inhibit angiogenesis induced by human tumor cells in vivo

BACKGROUND

Cationic porphyrin TMPyP4, but not its isomer TMPyP2, inhibits telomerase in tumor cells in vitro and induces chromosome destabilization in vivo.

MATERIALS AND METHODS

To examine the effects of these porphyrins on tumor-induced angiogenesis, 25-200 micrograms TMPyP4 or TMPyP2 were injected daily for 3 days in mice with intradermally implanted primary human tumor cells. Alternatively, tumor cells were exposed for 90 minutes to 2.5-20 microM porphyrins prior to implantation in mice.

RESULTS

Either subcutaneous injections (> or = 50 micrograms/mouse) or preincubation with > or = 5 microM porphyrins significantly inhibited angiogenesis.

CONCLUSION

Antiangiogenic activity is apparently unrelated to the ability of the porphyrins to inhibit telomerase.

Use of protein phosphatase inhibition assay to detect microcystins in Donghu Lake and a fish pond in China

Seasonal variations in the level of total microcystins in water samples collected from Donghu Lake and a fish pond in Wuhan, China, were studied between March 1995 and February 1996 using a protein phosphatase inhibition assay involving a radioactive 32P-labelled substrate. The assay is highly reliable and repeatable, and is probably the most sensitive assay for microcystin detection to date. Results of the survey indicated the presence of microcystins in the water samples, and the concentration of microcystins appeared to be related to the degree of eutrophication and water temperature. There is also a correlative relationship between the quantity of microcystins and the abundance of microcystin-producing cyanobacteria (Anabaena and Oscillatoria) in the water bodies over a year cycle. In the present study, the positive detection of microcystins in water bodies having no signs of algal bloom warns of considerable potential threat of these waters to public health.

Effects of cadmium and phenol on motility and ultrastructure of sea urchin and mussel spermatozoa

Computer-assisted sperm analysis (CASA) was used to study the effects of Cd(II) and phenol on sperm motility of sea urchin and mussel. In parallel, ultrastructural changes of sperm induced by these two toxicants were also investigated and related to motility impairment. Spermatozoa of sea urchin were more sensitive than mussel spermatozoa to both toxicants. Sea urchin sperm motility showed a good dose-response relationship to Cd(II) levels as well as exposure time. Exposure to the two toxicants changed the size and shape of the midpiece, which might affect the balance of spermatozoa in their swimming. The plasma membrane became more convoluted, and such a change might affect the streamlining and integrity of spermatozoa and hinder their normal movement patterns. Most important, disorganization of mitochondrial membranes and cristae was observed, suggesting disruption of ATP supply for sperm movement. Cadmium also induced greater ultrastructural damages in sea urchin spermatozoa.

Low-level doxorubicin resistance in benzo[a]pyrene-treated KB-3-1 cells is associated with increased LRP expression and altered subcellular drug distribution

The P-glycoprotein (P-gp)-negative epidermoid pharyngeal carcinoma cells KB-3-1 were grown in 0.25 mM benzo[a]pyrene (BaP) for 3 months and increased resistance to doxorubicin, but not to vinblastine, colchicine, or cisplatin, was found. Doxorubicin resistance was not altered by cyclosporin, the P-gp inhibitor. Intracellular accumulation of BaP or calcein, a substrate for P-gp and multidrug resistance protein (MRP), was not altered by inhibitors of the P-gp and MRP. The expression of cytochrome P450 (CYP) 1A1, lung-resistance-related protein (LRP), P-gp, and MRP was investigated. Overexpression of CYP1A and LRP, on the mRNA and protein levels, was found. BaP-treated KB-3-1 cells remained P-gp negative while the level of MRP was not altered. Subcellular accumulation of BaP was found to be localized in the cytoplasm and minimal in the nuclei in BaP treated cells. In contrast, even penetration of BaP to the nuclei and cytoplasm was found in untreated cells. Subcellular distribution of doxorubicin was altered following BaP treatment with localized accumulation of the cancer drug in cytoplasmic organelles but not in the nuclei. Our data suggested that LRP might play a protective role against toxic compounds. The correlation of increased expression of LRP, but not P-gp nor MRP, with decreased doxorubicin accumulation in the nuclear target suggests a pivotal role of this perinuclear transporter in the MDR phenotype of P-gp-negative cancer cells. These results also propose an alternative mechanism of cancer drug resistance emergence, namely, induction of LRP activity following treatment with BaP, an environmental toxicant and a carcinogen.

Construction of new amplifier expression vectors for high levels of IL-2 gene expression

The success of IL-2 gene therapy in cancer is in part dependent on the development of high level IL-2 gene expression vectors. Currently, expression vectors based on the human cytomegalovirus (CMV) promoter give the highest levels of expression. We have attempted to construct new IL-2 expression vectors to test whether gene expression can be further increased. The first approach was to use the new SR-alpha promoter to control IL-2 gene expression. The second approach was to combine the Tat transcription activator gene and the HIV 1 and 2 promoters in the same construct so that the levels of gene expression can be amplified. Transient transfection results using the human colon cancer cell line SW480 showed that the SR-alpha promoter yields similar levels of activity as the CMV promoter. However, the HIV 1 and 2 promoter-based amplifier constructs produced 11 and 28 times more secreted IL-2 than the CMV promoter control. The augmented activity of the amplifier constructs was dependent on the presence of the Tat gene and the transcriptional units must be placed in the same orientation. Reducing the size of the vectors by elimination of the neomycin selectable marker did not increase the activity of the constructs.

Effects of fenoterol and ipratropium on respiratory resistance of asthmatics after tracheal intubation

We have studied the effects of a beta-agonist, fenoterol, and a cholinergic antagonist, ipratropium, on post-intubation total respiratory system resistance (Rrs) in asthmatics who developed increased Rrs after tracheal intubation. Sixteen stable asthmatics in whom Rrs increased after intubation were allocated randomly to receive either 10 puffs of fenoterol (group F) or 10 puffs of ipratropium (group IB) via a metered dose inhaler 5 min after intubation. Anaesthesia was induced and maintained with propofol i.v. Rrs was recorded before treatment and again 5, 15 and 30 min after treatment. Rrs decreased significantly from pretreatment values by mean 53 (SD 8)%, 53 (7)% and 58 (6)% at 5, 15 and 30 min, respectively, in group F, but declined by only 12 (6)%, 15 (4)% and 17 (5)% in group IB. At all times after treatment, patients in the fenoterol group had significantly lower Rrs values than those in the ipratropium group. We conclude that increased Rrs after tracheal intubation in asthmatics can be reduced effectively by treatment with fenoterol. A secondary finding of our study was that even after induction of anaesthesia with propofol, patients with a history of asthma may develop high Rrs.

Propofol-sodium thiopental admixture reduces pain on injection

BACKGROUND

Propofol injection associated with a high incidence of pain is well known. Propofol and sodium thiopental mixture has recently been reported to be used for cost saving and able to reduce pain on injection.

METHODS

This prospective, randomized, double blind trial was designed to compare the efficacy of different percentages of propofol and sodium thiopental mixture in minimizing propofol injection pain. 146 ASA class 1 patients were assigned to seven groups (pure propofol, pure sodium thiopental, and propofol premixed with 10%, 20%, 30%, 40%, and 50% of sodium thiopental). The intensity of pain was graded and recorded as severe, moderate, mild and no pain according to the response of the patients to the injection.

RESULTS

The intensity of injection pain was significantly greater for pure propofol than the others while it was not significantly different among the other groups in comparison.

CONCLUSIONS

Sodium thiopental, when added to propofol, can significantly reduce propofol injection pain. This attenuation effect was noted even with as low as 10 volume % of sodium thiopental.

Telomere-interactive agents affect proliferation rates and induce chromosomal destabilization in sea urchin embryos

Cationic porphyrins, which interact with guanine quadruplex (G4) telomeric folds, inhibit telomerase activity in human tumor cells. In this study, we have further examined effects of porphyrins and other telomere- and telomerase-interactive agents on proliferation rates and chromosome stability in a novel in vivo model, developing sea urchin embryos. We studied two porphyrins: (i) TMPyP4, a potent telomerase inhibitor; and (ii) TMPyP2, an isomer of TMPyP4 and an inefficient telomerase inhibitor, azidothymine (AZT), the reverse transcriptase inhibitor, antisense phosphorothioate oligonucleotide to telomerase RNA (TAG6) and a control scrambled sequence (ODN). TMPyP4, AZT and TAG6 (but not TMPyP2 or ODN) decreased the rates of cell proliferation and increased the percentage of cells trapped in mitosis. Nuclear localization of TAG6, but not of ODN, was demonstrated with 5'-fluoresceinated analogs of TAG6 and ODN. Formation of elongated chromosomes incapable of separating in anaphase, induced by TMPyP4, AZT and TAG6, closely resembled phenotypes resulting from telomerase template mutation or dominant negative TRF2 allele. Our data suggest that G4-interactive agents exert their antiproliferative effects via chromosomal destabilization and warrant their further development as valuable anticancer tools.

Alternation of one-lung and two-lung ventilations with the same single-lumen endobronchial tube during thoracoscopic surgery--a case report

One-lung ventilation is sometimes necessary for procedures performed through thoracotomy. Single lumen endobronchial tube has been used purposefully for one lung ventilation since 1931. However, there are no reports on intra-operative alternation of one-lung and two-lung ventilations through the same single lumen endobronchial tube as it can only provide unilateral lung ventilation. We present a case in whom a tube exchanger was used to readjust tube position so as to provide alternation of one-lung and two-lung ventilations in a thoracoscopic procedure.

Fate and risk evaluation of persistent organic contaminants and related compounds in Victoria Harbour, Hong Kong

The Environment Protection Department of Hong Kong has a monitoring program for persistent organic contaminants in sediments of Victoria Harbour, the main harbour of Hong Kong. A fugacity model has been used, based on this sedimentary data, to estimate inputs to the system (probably from sewage, stormwater and industrial discharges) as well as the fate of the contaminants, particularly in terms of the aqueous and biotic concentrations. The risk of deleterious effects on the natural marine system, as well as on the consumers of seafood from the system, was carried out using the estimated aqueous and biotic concentrations together with accepted environmental quality guidelines. The result of our analysis indicated that the chlorohydrocarbons, PCBs (as Aroclor 1254) total DDT and total HCH pose a significant risk, and probably have caused damage to the marine ecosystem as well as posing a hazard to seafood consumers. Much higher concentrations of the less toxic total alkanes, nonaromatic hydrocarbons, linear alkyl benzenes and the compounds giving a unresolved complex mixture (UCM) cannot be evaluated due to a lack of environmental guidelines and the complexity of these substances. However, it is probable that these substances add adverse effects to those due to the other contaminants.

Recolonization and succession of marine macrobenthos in organic-enriched sediment deposited from fish farms

High organic loading deposited on the sea bottom by marine fish farming activities often eliminates benthic organisms in the vicinity. In this study, organic-enriched sediment collected underneath a fish farm was defaunated, placed in settling trays and exposed to the subtidal area of a clean site of similar hydrography. Trays were sampled monthly for a consecutive period of 5 months, and recolonization and successional patterns of macrobenthos were studied using univariate and multivariate statistics. Recolonization occurred rapidly, and averages of 144 animals/tray and 26 species/tray were recorded within the first month. Molluscs accounted for 49% of species and polychaetes for 77% of abundance during the first month of recolonization. Temporal changes in abundance, diversity and species composition found in subsequent months resembled spatial changes of benthic community along a decreasing pollution gradient generalised by Pearson and Rosenberg (1978, Oceanography & Marine Biology Annual Review 16, 229-311). Abundance reached a peak after 3 months (434 animals/tray) and then declined. Species number also increased, peaked after 4 months (47 species/tray), and was followed by a decrease. The polychaete Prionospio malmgreni succeeded Pseudopolydora paucibranchiata as the dominant species after the first month, reached a peak (194 animals/tray) after 3 months, then declined sharply. The rapid recolonization and succession of the macrobenthic community on organic-enriched sediment suggested that present fish farming methods are unlikely to have a long-term impact on benthic communities once farming activities are reduced/ceased.

Unexpected left endobronchial intubation in a case of Turner's syndrome

Patients with Turner's syndrome present a multiplicity of cardiovascular and airway abnormalities. We describe a case of Turner's syndrome with pericardial effusion who experienced an inadvertent endobronchial intubation due to displacement of the endotracheal tube immediately after the pericardial drainage. A sudden increase of airway pressure and decrease of oxygen saturation in the presence of breathing sound audible via the chest piece placed on the left hemithorax first misled us to call our attention to sputum impaction. No sputum was obtainable from airway suction. Inadvertent bronchial intubation was highly suspected at the post-anesthesia room when a decrease of right side breathing sound was noted together with a progressive fall of oxygen saturation. Emergent chest x-ray confirmed the diagnosis. It was thought that the mishap took place early in the act of or following the pericardial drainage. Our case serves as evidence once again to emphasize the possibility of endobronchial intubation due to displacement of endotracheal tube during anesthesia and the importance of monitoring to guard against inadvertent bronchial intubation, particularly in patients with associated problems such as Turner's syndrome with huge pericardial effusion.

New synthesis and characterization of (+)-lysergic acid diethylamide (LSD) derivatives and the development of a microparticle-based immunoassay for the detection of LSD and its metabolites

In this paper are reported the synthesis and characterization of three LSD derivatives. On the basis of several analytical characterization studies, the most stable derivative has been selected and a procedure to covalently link the derivative to polystyrene microparticles through a carrier protein has been developed. In addition, two new LSD immunogens have been synthesized and characterized, and from these immunogens antibodies that recognize not only LSD but also several major LSD metabolites have been generated. Using the selected derivative and antibody, a homogeneous microparticle-based immunoassay has been developed for the detection of LSD in human urine with the required sensitivity and specificity for an effective screening assay. The performance of this LSD OnLine assay has been evaluated using the criteria of precision, cross-reactivity, correlation to the Abuscreen LSD RIA and GC/MS/MS, assay specificity, and limit of detection.

Epimerization studies of LSD using 1H nuclear magnetic resonance (NMR) spectroscopy

A study was conducted to determine the conditions needed to achieve the equilibrium concentration for the epimerization of d-lysergic acid diethylamide (LSD) to iso-LSD. The reaction was followed by integration of the C-9 resonance of LSD and iso-LSD by proton nuclear magnetic resonance (NMR). The C-9 resonance of LSD and iso-LSD appear as singlets at 6.35 and 6.27 ppm respectively. Starting with pure LSD, the conversion to iso-LSD is attained at temperatures above 37 degrees C and pH levels over 7.0. At a pH of 7.0 or higher, the LSD/iso-LSD ratio of 9:1 is achieved after one week at 45 degrees C or two weeks at 37 degrees C. Starting with iso-LSD, the conversion to LSD requires more vigorous conditions. The 9:1 LSD/iso-LSD ratio is attained only after 6 weeks at a temperature of 45 degrees C and a pH of 9.7. At lower pH levels, the reaction proceeds more slowly. The 9:1 LSD/iso-LSD ratio is achieved whether the starting material is LSD or iso-LSD and therefore represents an equilibrium concentration (K = 9). In addition, the more vigorous conditions needed to achieve equilibrium of iso-LSD to LSD demonstrate the difficulty in extraction of the epimerizable proton of iso-LSD. This study is the first to quantitate the epimerization of LSD by NMR techniques and establishes the conditions needed to induce epimerization in solution.

Evoked facial nerve EMG and brainstem auditory evoked potential monitoring in cerebellopontine angle tumor resection

BACKGROUND

The preservation of normal nerve function or identification of nerve route is critical in some surgeries of cerebellopontine angle tumors. Over the last 5 years, intraoperative facial nerve electromyogram (EMG) and brainstem auditory evoked potential (BAEP) were applied for evaluation of facial nerve integrity and brainstem function in patients while undergoing resection of cerebellopontine angle (CPA) tumor. This report represents the retrospective analysis of our results.

METHODS

The inhalational anesthesia with 1-1.5% isoflurane in pure O2 was used. Muscle relaxation was maintained with continuous infusion of atracurium. The degree of muscle relaxation was aimed at a T4/T1 ratio of train-of-four response more than 20% of the adductus pollicis upon ulnar nerve stimulation at the wrist. In 236 patients suffering from CPA tumor without facial palsy, the EMG of the mentalis muscle ipisilateral to the tumor was obtained through stimulation of the facial nerve. The stimulation was applied with a nerve finder, which delivered an electrical stimulation of a single 2 mamp direct current. The EMG finding was compared with the clinical result. In 198 patients, BAEP was used to monitor the brainstem function during tumor resection. In case of intact hearing the BAEP was taken ipsilateral to the operation side and in case with total hearing loss contralateral BAEP to operation side was used. For BAEP stimulation, 90 db click sound stimulation with frequency of 11.26 Hz was applied to both ears. BAEP signals were obtained and recorded at the mastoid region of either side in reference to the vertex. The EMG and BAEP signals were recorded and saved to an evoked potential monitor.

RESULTS

In facial nerve EMG monitoring, there were two false positive and no false negative tests. Except for the two false positive tests, the postoperative clinical results in the other cases were compatible with the intraoperative facial nerve EMG findings. In BAEP monitoring, there were twenty-eight positive tests.

CONCLUSIONS

The low incidence of false negative test suggests that facial nerve EMG is valuable in detection of facial nerve function in CPA tumor resection. Intraoperative BAEP abnormality is possibly useful in identifying postoperative brainstem dysfunction.

Dislodgment of catheter during arterial cannulation: a case report

Invasive blood pressure monitoring is important in medical practice, especially for hemodynamic monitoring of the critically ill. Catheter dislodgment is a rarely reported complication. We herein report a catheter dislodgment complication during the procedure of arterial cannulation.

Endotracheal tube size selection guidelines for Chinese children: prospective study of 533 cases

Appropriate selection of the size of an endotracheal tube (ETT) for use in children is important both in general anesthesia and critical care practice. Past published data on guidelines for selecting ETT size in children are based on Caucasian measurements. As body build is generally different in Chinese children compared with Caucasians of the same age group, guidelines for Chinese children are needed. The aim of this study was to determine guidelines for ETT size selection by recording and comparing age, body weight, length, head girth and circumference of the right fifth finger of the child. Correlations between internal diameter (ID) of the chosen ETT and the child's data were calculated and compared. In this study, 533 Chinese children. American Society of Anesthesiolgists class I or II, aged from 3 months to 6 years, undergoing oral intubation for general anesthesia for minor pediatric surgery were enrolled. Our results showed that body length (height) had the best correlation to the size of an uncuffed oral ETT. Through stepwise regression, a formula. ETT ID = 2 + (body length (cm)/30), was obtained.

Synthesis of new d-propoxyphene derivatives and the development of a microparticle-based immunoassay for the detection of propoxyphene and norpropoxyphene

The synthesis of [S-(R,S)]-4-[[methyl[2-methyl-3-(1-oxopropoxy)-3, 4-diphenylbutyl]amino]-1-oxobutoxy]-2,5-pyrrolidinedione+ ++ (propoxyphene active ester, 2) is described. This was used as an intermediate to prepare a propoxyphene immunogen, [S-(R,S)]-4-[methyl][2-methyl-3-(1-oxopropoxy)-3,4-diphenylbuty l]-amino]- 1-oxobutyl-Bovine Thyroglobulin (3). This immunogen was then used to generate antibodies which demonstrate good cross-reactivity to d-propoxyphene, d-norpropoxyphene, and other propoxyphene metabolites. In addition, these antibodies were shown to have very low cross-reactivity to methadone, a structurally related compound. The introduction of an aminomethyl benzoate spacer into the propoxyphene active ester (2), followed by the activation of the carboxylic acid, provided for a more stable active ester (5). This stable active ester, together with the antibodies generated from the propoxyphene immunogen, has led to the development of an immunoassay based on the Kinetic Interaction of Microparticles in Solution (KIMS).

Comparative effects of thiopentone and propofol on respiratory resistance after tracheal intubation

To compare the effects of propofol and thiopentone on tracheal intubation-induced bronchoconstriction, 37 patients were allocated randomly to anaesthesia with either thiopentone 4 mg kg-1 followed by a 15-mg kg-1 h-1 continuous infusion or propofol 3 mg kg-1 followed by a 9-mg kg-1 h-1 continuous infusion. Intubation was facilitated by vecuronium 0.1-0.2 mg kg-1. Respiratory system resistance (Rrs) was measured by a CP-100 pulmonary function monitor, 5 min after intubation. The 5-min post-intubation Rrs values were significantly lower in the propofol group (8.5 (SD 1.5) cm H2O litre-1 S-1) than in the thiopentone group (10.9 (3.2) cm H2O litre-1 S-1). Thirty minutes after commencing isoflurane-nitrous oxide anaesthesia, Rrs declined by 17.5 (SEM 3.6)% from baseline in the thiopentone group, but by only 1.6 (2.6)% in the propofol group. We conclude that the dose of propofol administered provided more protection against tracheal intubation-induced bronchoconstriction than an induction dose of thiopentone.

High dose intravenous labetalol for the resection of metastatic pheochromocytoma

A case of intrahepatic metastatic pheochromocytoma with lymph nodes involvement undergoing resection of tumor was reported; intravenous labetalol in high dose regimen (2 mg/kg administered before skin incision) was used for blood pressure control during the operation. Marked sinus bradycardia was noted after receiving total dose of intravenous labetalol and treated [corrected] with intravenous atropine 0.4 mg. The total operation time was 6.5 h. We found that under isoflurane anesthesia, duration of action of intravenous labetalol was prolonged as adequate intraoperative blood pressure control was obtained throughout the 6-h surgical period without further need of supplementary medication. This finding suggested that duration of labetalol was extended when concomitantly used with isoflurane and the labetalol dosage in our regimen could be effectively used in surgical procedures lasting for more than 6 h.

Isoflurane anesthesia does not add to the bronchodilating effect of a beta 2-adrenergic agonist after tracheal intubation

This double-blind study investigates whether isoflurane/N2O anesthesia adds to the bronchodilating effect of the beta 2-adrenergic agonist, fenoterol, after an endotracheal tube (ETT)-induced increase in airway resistance. Forty-five patients with ASA physical status I-II were randomly assigned to two groups: fenoterol-treated patients (n = 23) were given three metered-dose inhaler puffs (600 micrograms) of fenoterol 10 min before induction of anesthesia and placebo-treated patients (n = 22) received three puffs of an aerosol containing no medication. Anesthesia was induced with thiopental and vecuronium intravenously. Respiratory system resistance (Rrs) was measured using a CP-100 pulmonary function monitor 5 min after endotracheal intubation. Inhalation anesthesia was then begun using 50% N2O in O2 with end-tidal 1.3% isoflurane. Rrs measurements were repeated at 5, 15, and 30 min after the initiation of inhalation anesthesia. Postintubation Rrs was significantly lower in the fenoterol-treated patients than in the placebo-treated patients. Rrs declined by a mean of 17.1% after 30 min of inhalation anesthesia in the placebo-treated patients but declined by only 1.4% in the fenoterol-treated patients (P < 0.05 for fenoterol provides protection versus placebo). Our results confirm that fenoterol provides protection against ETT-induced increase of airway resistance. However, isoflurane, while a potent bronchodilator, does not add to the effect of fenoterol.

Comparison of the effects of etomidate, propofol, and thiopental on respiratory resistance after tracheal intubation

BACKGROUND

Tracheal intubation frequently results in reversible bronchoconstriction. Propofol has been reported to minimize this response in healthy patients and in asthma patients, but may be unsuitable for hemodynamically unstable patients for whom etomidate may be preferable. The current study examined respiratory resistance after tracheal intubation after induction with either thiopental, etomidate, or propofol. A supratherapeutic dose of etomidate was used to test the hypothesis that the bronchoconstrictive response could be minimized by deep intravenous anesthesia.

METHODS

Seventy-seven studies were conducted in 75 patients. Anesthesia was induced with either 2.5 mg/kg propofol, 0.4 mg/kg etomidate, or 5 mg/kg thiopental. Respiratory resistance was measured at 2 min after induction.

RESULTS

Respiratory resistance at 2 min was 8.1 +/- 3.4 cmH2O.1(-1).s (mean +/- SD) for patients receiving propofol versus 11.3 +/- 5.3 for patients receiving etomidate and 12.3 +/- 7.9 for patients receiving thiopental (P < or = 0.05 for propofol vs. either etomidate or thiopental).

CONCLUSIONS

Respiratory resistance after tracheal intubation is lower after induction with propofol than after induction with thiopental or after induction with high-dose etomidate.

Inhaled fenoterol pretreatment attenuates airway resistance response to endotracheal intubation

BACKGROUND

Endotracheal intubation may induce vagal mediated bronchoconstriction. As fenoterol possesses bronchodilation effects, we studied the efficacy of fenoterol pretreatment on the increased resistance of total respiratory system (Rrs) caused by reflex bronchoconstriction in endotracheal intubation.

METHODS

Fifty patients were randomly allocated into two groups; group A (n = 25) with fenoterol inhaled and group B (n = 25) with placebo inhaled 10 min before induction. Patients were induced with sodium thiopental and vecuronium and resistance was measured 2 and 5 min after intubation with a Bicore pulmonary function monitor. Suctioning of the airway was performed 1 min before each measurement. Patients were further categorized into four conditions by smoking history and the presence of sputum in the suctionings. Condition I included patients that were smokers with no sputum collected. Condition II had non-smokers with no sputum collected. Condition III had patients with sputum collected but with no smoking history and condition IV were patients who had sputum collected and had a smoking history.

RESULTS

Patient who received fenoterol have significant lower total respiratory after intubation than those receiving placebo. There were no significant differences in post-intubation Rrs between smokers and non-smokers. Patients with sputum had the highest resistance after intubation with the placebo group. Heart rate and blood pressure were augmented in both groups.

CONCLUSIONS

Fenoterol pretreatment produced lower post-intubation Rrs after intubation when compared with the placebo group suggesting of a protective effect in vagal mediated bronchoconstriction.

Prior epidural injection of 10 ml normal saline reduces the incidence of inadvertant venous puncture in epidural catheterization

BACKGROUND

Anesthetically, epidural neural blockade is widely used in the fields of surgery and obstetrics as well as in diagnosis and management of acute and chronic pain. However, inadvertent epidural venous puncture might be a serious problem, or even life-threatening particularly when drug is erronaneously injected and prompt diagnosis is not made correct and treatment is not instituted. Although many anesthesiologists suggested that injection of fluid into the epidural space before catheter insertion could prevent an epidural venous puncture, some others did not agree to it. This study aimed a assess the effect of injection of different volumes of saline into the epidural space before catheter insertion on the incidence of epidural venous puncture.

METHODS

Three hundred ASA I or II patients receiving Extracorporeal Shock Wave Lithotripsy (ESWL) were randomly divided into three groups: group A (no saline), group B (5 ml of saline) and group C (10 ml of saline). After the injection of different volume of saline into the epidural space, an epidural catheter was inserted into the epidural space via a Touhy needle. The incidence of epidural venous puncture in each group was compared.

RESULTS

The incidence of epidural venous puncture in group A and B was 14% and 11%, respectively. However, the incidence in group C (1%) was significantly lower than the other two groups.

CONCLUSIONS

Our results suggest that injection of 10 ml saline into the epidural space before catheter insertion could significantly diminish the incidence of epidural venous puncture.

A new method of maintaining airway during nasotracheal intubation--the hand mask technique

The efficacy of a new method (The hand mask technique) for airway maintenance during nasotracheal intubation was evaluated in our randomized crossover study. Sixty, age less than 50, ASA physical status class I-II patients undergoing surgery for the extremities with informed consent were randomly chosen for the study. Pulse oximeter, capnometer, EKG, blood pressure monitor and a peripheral nerve stimulator were attached to the patients before induction for continuous monitoring. An arterial cannula was inserted for intermittent blood gas sampling. After baseline room air blood gas data had been obtained from the spontaneously breathing patients, a flow rate of 6L/min pure oxygen was applied through a loosely fitted face mask and a semi-closed anesthesia breathing circuit for a period of 5 minutes. An arterial blood sample was drawn and the patients were put under general anesthesia with full muscle relaxation thereafter. Patients were then randomly assigned into two groups according to the ventilation technique used. Group A patients (n = 30) were manually ventilated first through a face mask for ten minutes and then the hand mask technique for another ten minutes. Blood gas data was sampled and heart rate, blood pressure, peak inspiratory airway pressure and end tidal CO2 were recorded immediately after each ventilation technique. For patients in Group B (n = 30), the sequence of the two ventilation technique were reversed. The results showed significant increases in PaO2 after artificial ventilation in both groups (No significant difference in results between the two groups) and less incidence of nasal bleeding in Group A.(ABSTRACT TRUNCATED AT 250 WORDS)

[Anesthesia for tracheal reconstruction supported by tracheal T-tube--a modification of the Montgomery's method]

Even though high frequency ventilation is the most important anesthetic ventilation technique for patients who have tracheal T-tube, other method is still in use, especially the Montgomery's method. In our daily practice, we found that there are some practical problems in the application of the Montgomery's method. Firstly, air leakage is present due to the presence of the Fogarty catheter at the connection of T-tube and endotracheal tube. Secondly, the internal diameter of the extraluminal limb of T-tube is smaller than the internal diameter of the intraluminal limbs, and the internal diameter of the endotracheal tube is smaller than the internal diameter of the extraluminal limb. This causes an increase in airway pressure in some patients. Thirdly, the endotracheal tube may kink and reduce the effective size of the lumen. Fourthly, the operation field may be interfered by the tube. We have designed a modification to solve these problems. A non-kinking endotracheal tube was used and the distal end of the non-kinking endotracheal tube was pushed to fit into the extraluminal limb of a T-tube. The other proximal end was connected to a mask elbow which was equipped with a sampling port. A Fogarty catheter was passed through the sampling port of the mask elbow and the trio attachment (mask elbow, non-kinking endotracheal tube, and T-tube) into the upper intraluminal limb of the T-tube. The balloon of the Fogarty catheter was inflated to occlude the opening of the upper intraluminal limb. Ventilation was performed by connecting the free end of the mask elbow to the anesthesia ventilator.(ABSTRACT TRUNCATED AT 250 WORDS)

The thermoregulation of halothane versus isoflurane in humans receiving ophthalmological surgery

Although suppression of thermoregulatory mechanisms during anaesthesia is generally assumed, the extent to which thermoregulation may be inactive is unknown. Twenty unpremedicated, ASA physical status class I patients (17 men and 3 women) scheduled for retinal detachment surgery were studied to evaluate the different changes of core and two skin-surface temperatures during halothane or isoflurane anaesthesia. Anaesthesia was induced by mask inhalation of halothane or isoflurane in nitrous oxide 70% and oxygen and was maintained by mechanical ventilation during surgery with halothane or isoflurane in nitrous oxide 50% and oxygen only. Core temperature (rectus) and skin-surface temperatures (forearm and fingertip) were measured during surgery using three separate thermometers (Y.S.I.: Yellow springs instrument Co., Inc. G541-211-Y01-33A0). Operating room temperatures were recorded in every case. Significant vasoconstriction was prospectively defined by a skin-surface temperature gradient between two sampling sites > or = 4 degrees C. The result indicated that there was no significant difference between core temperatures and skin-surface temperature gradients during halothane anaesthesia and isoflurane anaesthesia. However, three of the ten patients had their skin-surface temperature gradients > or = 4 degrees C in the halothane group. None of the ten patients had their skin-surface temperature gradients > or = 4 degrees C in the isoflurane group.