Aldehyde-Induced Cytotoxicity in Cultured Human Bronchial Epithelial Cells

Effects of the tobacco smoke related aldehydes, i.e. acetaldehyde, formaldehyde and acrolein, have been investigated in cultured human bronchial epithelial cells. When survival is measured as loss of colony-forming efficiency, acrolein is 200–fold and 5000–fold more toxic than formaldehyde and acetaldehyde, respectively. At cytotoxic concentrations, the cellular content of free thiols is markedly depleted by acrolein, whereas formaldehyde and acetaldehyde only slightly decrease thiols. These aldehydes cause many other pathobiological effects in human cells that relate to the initiation and promotion phases of carcinogenesis, including: DNA damage, mutation, inhibition of DNA repair, and squamous differentiation. Interpretation of the importance of these cytopathic effects in carcinogenesis has to be based on accurate determinations of aldehyde-induced cytotoxicity.

Vasospastic phenomena in patients treated with beta-adrenoceptor blocking agents

Twenty-one patients developed Raynaud's phenomenon during treatment with beta-adrenoceptor blocking agents. The vasospastic symptoms were obviously related to the treatment, but their pathogenesis is still controversial. A decrease in cardiac output might explain the phenomenon. According to our very preliminary data an alpha-adrenergic dominance caused by a direct effect on the peripheral circulation seems more probable. Vasospastic symptoms may arise after treatment with both cardioselective and non-selective beta blocking agents. Cautious prescription of beta blocking drugs to patients with preexisting peripheral vascular disease is recommended.

Peripheral vasospasm during beta-receptor blockade - a comparison between metoprolol and pindolol

Ten men reported vasospastic symptoms in their hands during metoprolol treatment. They had no signs of occlusive arterial disease. The temperature reaction to local cooling was measured and no improvement was found after changing to pindolol. Vasospastic symptoms during beta-receptor blockade may arise in predisposed individuals irrespective of the type of beta-receptor antagonist used.

First results from the Cryogenic Dark Matter Search in the Soudan Underground Laboratory

We report the first results from a search for weakly interacting massive particles (WIMPs) in the Cryogenic Dark Matter Search experiment at the Soudan Underground Laboratory. Four Ge and two Si detectors were operated for 52.6 live days, providing 19.4 kg d of Ge net exposure after cuts for recoil energies between 10 and 100 keV. A blind analysis was performed using only calibration data to define the energy threshold and selection criteria for nuclear-recoil candidates. Using the standard dark-matter halo and nuclear-physics WIMP model, these data set the world's lowest exclusion limits on the coherent WIMP-nucleon scalar cross section for all WIMP masses above 15 GeV/c2, ruling out a significant range of neutralino supersymmetric models. The minimum of this limit curve at the 90% C.L. is 4 x 10(-43) cm2 at a WIMP mass of 60 GeV/c2.

Randomised trial of cranberry-lingonberry juice and Lactobacillus GG drink for the prevention of urinary tract infections in women

OBJECTIVE

To determine whether recurrences of urinary tract infection can be prevented with cranberry-lingonberry juice or with Lactobacillus GG drink.

DESIGN

Open, randomised controlled 12 month follow up trial.

SETTING

Health centres for university students and staff of university hospital.

PARTICIPANTS

150 women with urinary tract infection caused by Escherichia coli randomly allocated into three groups.

INTERVENTIONS

50 ml of cranberry-lingonberry juice concentrate daily for six months or 100 ml of lactobacillus drink five days a week for one year, or no intervention.

MAIN OUTCOME MEASURE

First recurrence of symptomatic urinary tract infection, defined as bacterial growth >/=10(5 )colony forming units/ml in a clean voided midstream urine specimen.

RESULTS

The cumulative rate of first recurrence of urinary tract infection during the 12 month follow up differed significantly between the groups (P=0.048). At six months, eight (16%) women in the cranberry group, 19 (39%) in the lactobacillus group, and 18 (36%) in the control group had had at least one recurrence. This is a 20% reduction in absolute risk in the cranberry group compared with the control group (95% confidence interval 3% to 36%, P=0.023, number needed to treat=5, 95% confidence interval 3 to 34).

CONCLUSION

Regular drinking of cranberry juice but not lactobacillus seems to reduce the recurrence of urinary tract infection.

Toxicity of formaldehyde to human oral fibroblasts and epithelial cells: influences of culture conditions and role of thiol status

The toxicity of formaldehyde, a monomer released from certain polymeric dental materials, was studied in cultured human oral fibroblasts and epithelial cells. The influences of growth conditions were evaluated for both cell types, as well as the role of the internal and external thiol states. A one-hour exposure to formaldehyde decreased the colony-forming efficiency (CFE) of both cell types in a concentration-dependent manner, although the toxicity varied up to 100-fold with the conditions. Clearly, the presence of serum and the thiol cysteine counteracted the toxicity in fibroblasts. Similarly, pituitary extract and cysteine, or a mixture of amino acids and ethanolamines, counteracted the formaldehyde toxicity in serum-free cultures of epithelial cells. In contrast, a growth-promoting surface matrix of fibronectin and collagen did not influence the formaldehyde toxicity, as shown by both the CFE assay and a dye reduction assay. Further, a short-term change to the various growth media per se with or without the supplements serum or cysteine did not significantly alter the CFE. Analysis of the thiol state demonstrated significant differences between epithelial cells and fibroblasts, i.e., comparatively lower cellular levels of the free low-molecular-weight thiols glutathione and cysteine in fibroblasts. This result correlated to significantly higher formaldehyde toxicity in the fibroblasts than in the epithelial cells. Taken together, the results indicated the cytoprotective function of both intracellular and extracellular thiols toward formaldehyde, as well as the usefulness of thiol-free and chemically defined conditions for toxicity assessments in oral epithelial cells and fibroblasts. We conclude that the combined use of a controlled external milieu and the presumed target cell type may be advantageous in evaluations of oral toxicity mechanisms or the toxic potency of dental materials, particularly those which, like formaldehyde, may react with thiols or amines.

Identification of genes overexpressed in the sqcc/y1 human buccal carcinoma cell-line using the differential display method

Although several oncogenes and tumor suppressor genes have been suggested to be of relevance for the development of oral cancer, it is likely that additional genes are involved in this complex process. Therefore, in an attempt to isolate such genes, the aim of this study was to investigate changes in gene expression in human buccal carcinoma cells as compared to normal buccal epithelial cells, and identify mRNA overexpressed in the carcinoma cell line. The method of differential display of mRNA was used to isolate differentially expressed genes (Liang P et al, Science 257:967-971, 1992). A key step of this method, a polymerase chain reaction amplification, was optimized in terms of choice of thermostable DNA polymerase, annealing temperature, molar ratios and concentrations of primers. The comparative analysis of expression in tumor and normal buccal epithelial cells led to the isolation of three different mRNAs overexpressed in human oral carcinoma cells, as confirmed by Northern blot analysis. Cloning and sequence analysis revealed that these genes, which were termed OTEX as in Oral Tumor EXpressed, included a novel, previously not characterized, human gene, OTEX-1. OTEX-2 was identical to the gene coding for the L26 ribosomal protein, a protein known to be overexpressed also in other tumor cell types. OTEX-3 showed a perfect match to a sequence isolated during the human genome sequencing project, with a hitherto unknown function.

Characterization of human buccal epithelial cells transfected with the simian virus 40 T-antigen gene

Serum-free cultures of normal human buccal epithelial cells were transfected with a plasmid containing the SV40 T-antigen (SV40T) gene. Two major lines developed that showed extended lifespans (between 30 and 40 weeks) as compared with the controls (approximately 6 weeks). Continued growth through one or two crises generated several sublines. They expressed the epithelial marker keratin and also exhibited nuclear expression of SV40T. The lines showed abnormal karyotypes with both numerical and structural aberrations and variably responded to agents that normally inhibit growth and/or induce terminal differentiation, i.e. transforming growth factor-beta 1 and fetal bovine serum. One of the lines, termed SVpgC2a, developed into an apparently immortal line, since it had undergone more than 700 population doublings from over 2 years in culture. Further characterization of this line demonstrated its clonal origin, with integration of two copies of SV40T at the same site and the presence of both normal retinoblastoma and wild-type p53 proteins. This line showed high resistance to growth inhibition by transforming growth factor-beta 1 and serum similar to that shown by buccal carcinoma cell line SqCC/Y1. Neither SVpgC2a nor its parental lines were tumorigenic when injected into athymic nude mice, whereas the SqCC/Y1 cells induced tumors. The various lines with extended but finite lifespans, complemented by one immortalized line, which retained non-malignant properties upon extended culture, provide a battery of model systems that will be useful for studying mechanisms of human oral carcinogenesis.

Pathobiological effects of acetaldehyde in cultured human epithelial cells and fibroblasts

The ability of acetaldehyde, a respiratory carcinogen present in tobacco smoke and automotive emissions, to affect cell viability, thiol status and intracellular Ca2+ levels and to cause DNA damage and mutations has been studied using cultured human cells. Within a concentration range of 3-100 mM, a 1 h exposure to acetaldehyde decreases colony survival and inhibits uptake of the vital dye neutral red in bronchial epithelial cells. Acetaldehyde also causes both DNA interstrand cross-links and DNA protein cross-links whereas no DNA single strand breaks are detected. The cellular content of glutathione is also decreased by acetaldehyde, albeit, without concomitant changes in the glutathione redox status or in the content of protein thiols. Transient or sustained increases in cytosolic Ca2+ occur within minutes following exposure of cells to acetaldehyde. Moreover, acetaldehyde significantly decreases the activity of the DNA repair enzyme O6-methylguanine-DNA methyltransferase. Finally, a 5 h exposure to acetaldehyde causes significant levels of 6-thioguanine resistance mutations in an established mutagenesis model involving skin fibroblasts. The results indicate that mM concentrations of acetaldehyde cause a wide range of cytopathic effects associated with multistep carcinogenesis. The fact that acetaldehyde, in relation to its cytotoxicity, causes comparatively higher genotoxicity and inhibits DNA repair more readily than other major aldehydes in tobacco smoke and automotive emissions is discussed.

Metabolism and macromolecular interaction of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in cultured explants and epithelial cells of human buccal mucosa

Metabolism and macromolecular interaction of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were studied in human buccal mucosa in vitro. Microautoradiographic analysis of [5-3H]NNK-exposed explant cultures demonstrated a uniform distribution of bound radioactivity in the mucosal epithelium, without significant binding in the underlying connective tissue. The metabolism of [5-3H]NNK at concentrations of both 6 and 100 microM resulted in seven identified metabolites in both explant and epithelial cell cultures. Formation of 4-(methylnitrosamino)-1-(3-pyridyl)butan-1-ol by carbonyl reduction of NNK accounted for almost 95% of the total metabolism, whereas the proportions of other metabolites obtained by alpha-carbon hydroxylation and pyridine N-oxidation reactions varied from undetectable levels to approximately 2% in both experimental systems. A positive correlation between concentration and the metabolic route associated with the formation of DNA methylating intermediates (alpha-hydroxylation at the N-methylene carbon) was found, i.e. when the concentration of NNK was raised from 6 to 100 microM, keto-acid formation which in part reflects DNA methylation was increased preferentially over ketoalcohol production, an index of DNA pyridyloxobutylation. Both the total rate of NNK metabolism and the amount of protein adducts were higher in cells from primary cultures up to the third passage than in explants cultured for 1 day. Between 10(-9) to 10(-4) M, neither NNK nor its precursor alkaloid nicotine affected the colony forming efficiency of normal and tumorous buccal epithelial cells, although at 10(-3) M each agent inhibited this function. Taken together, the results demonstrate the capability of human buccal mucosal epithelium to metabolize NNK by three major pathways, including those involved in the formation of adducts with cellular macromolecules.

Effect of autonomic blockade on digoxin-induced ECG changes at rest and during exercise in healthy subjects

The effect of pharmacological autonomic blockade on digoxin-induced electrocardiographic changes at rest and during exercise was studied in nine healthy men. The subjects performed bicycle exercise tests on four occasions after: (1) intravenous injection of sodium chloride, (2) intravenous injection of propranolol and atropine, (3) oral ingestion of digoxin 0.5 mg daily for 2 weeks and intravenous injection of sodium chloride, and (4) oral ingestion of digoxin 0.5 mg daily for 2 weeks and intravenous injection of propranolol and atropine. The ST-T segment was significantly depressed after digoxin plus sodium chloride and digoxin plus propranolol and atropine in comparison with sodium chloride only and propranolol and atropine only. The digoxin-induced ST-T changes after sodium chloride and propranolol-atropine injections were not significantly different. Thus, judging from the results of this study, an effect mediated via the autonomic nervous system is an unlikely explanation of digitalis-induced ST-T changes.

Effects of areca nut on growth, differentiation and formation of DNA damage in cultured human buccal epithelial cells

Because the high incidence of oral cancers in South-East Asia is causally linked to the common habit of betel quid chewing, the effects of an aqueous extract of areca nut, one of the main ingredients of the quid, on growth, differentiation, morphology and DNA damage were studied in cultured human buccal epithelial cells. An acute exposure (3 hr) of the cells to the extract altered their morphology and induced ridges in the plasma membrane, with indications of internalization of extract particles. Such exposure also caused formation of DNA single-strand breaks which accumulated during post-treatment culture, indicating continuous exposure to residual particles and/or the possibility of inhibited DNA repair. The extract accelerated terminal differentiation of the cells, measured as involucrin expression at relatively non-toxic levels. The extract caused similar loss of colony-forming efficiency in normal cells and in a buccal carcinoma cell line (SqCC/YI) which was defective in its ability to undergo differentiation, indicating that extract toxicity could occur independently from this response. Finally, the genotoxicity of the salivary areca-nut-specific carcinogen 3-(N-nitrosomethyl-amino)propionaldehyde, was demonstrated by the formation of DNA protein cross-links and DNA single-strand breaks in normal buccal epithelial cells. These findings in vitro suggest that betel quid carcinogenesis in the human oral cavity may involve cytopathic alterations of normal cell morphology, growth and differentiation, as well as formation of DNA damage by areca-nut-related agents extracted or formed in saliva.

Development of low- and high-serum culture conditions for use of human oral fibroblasts in toxicity testing of dental materials

With the aim of establishing conditions applicable to the testing of dental materials in human target cells, fibroblastic cell lines have been derived and grown from explants of human oral mucosa. Both a high-serum medium (termed "HSM") (CMRL 1066 supplemented with 10% fetal bovine serum) and a low-serum medium (termed "LSM") (a 1:1 mixture of M 199:MCDB 153 supplemented with 1.25% serum) supported radial outgrowths of cells from oral explants, as well as the subsequent transfer and growth of the cells in mass culture and at clonal density. Cells were typically fibroblastic in that they expressed vimentin uniformly, but did not express immunocytochemical markers of epithelial or endothelial cells. Cells derived in either LSM or HSM showed significantly higher colony-forming efficiency and clonal growth rate when transferred in LSM, as compared with HSM. Because cell migration occurred to a lesser extent in LSM, microscopic scoring of colony formation was also markedly facilitated. In both LSM and HSM, cellular low-molecular-weight thiols constituted about 30% of the total amount of sulfhydryls. Glutathione was present in about six- to seven-fold-higher amounts than cysteine--glutathione primarily in its reduced form and cysteine primarily in its oxidized form. A corrosion product of dental amalgam, i.e., Hg2+, decreased cell survival measured as colony-forming efficiency in a dose-dependent manner following either an acute (one h) exposure or continuous exposure (seven days). These studies demonstrated that human oral fibroblasts could be cultured at about one-tenth of the serum content that is commonly used.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth regulation of serum-free cultures of epithelial cells from normal human buccal mucosa

Human buccal epithelial cells have been reared from explants maintained in supplemented MCDB 153 medium. Primary epithelial outgrowths show typical structural features and uniformly express keratins; subunit analyses demonstrate expression of keratins 5, 6, 14, 16/17, and 19. The cells exhibit up to 6% colony forming efficiency and divide at about 0.8 population doublings per day on fibronectin/collagen-coated dishes at clonal density. Studies of markers of proliferation and differentiation in buccal epithelial cells indicate that epidermal growth factor, cholera toxin, retinoic acid, and pituitary extract each exhibit a distinctive ability to enhance growth and variably affect cell migration and cell surface area. Transforming growth factor beta-1 inhibits growth and increases surface area without affecting migration, involucrin expression, and cross-linked envelope formation. Moreover, exposure of cells to fetal bovine serum, the tumor promoting agent 12-O-tetradecanoylphorbol-13-acetate or an elevated Ca2+ concentration (from 0.1 to 1 mM) inhibits growth and induces squamous differentiation as indicated by inhibition of migration, increases in surface area, involucrin expression, or formation of cross-linked envelopes. The results show that epithelial cells can be reproducibly derived from explant cultures of human buccal mucosa specimens and the cells transferred under serum-free conditions. Buccal epithelial cells in culture undergo a pattern of growth and differentiation that mimics parakeratinization in vivo and variably respond to several agents shown to modulate growth of cells that originate from other types of epithelia.

Serum-free growth and karyotype analyses of cultured normal and tumorous (SqCC/Y1) human buccal epithelial cells

Epithelial cell cultures were obtained following tryptic digestion of normal human buccal mucosa. Primary cultures exhibited markedly higher colony-forming efficiencies and growth rates using fibronectin/collagen-coated, as compared to non-coated culture dishes and a serum-free MCDB 153 medium developed for epidermal epithelial cells than a similar medium previously developed for buccal explant outgrowth cultures. At the preferred conditions, the cells could be transferred at least 5-fold, divided at about one population doubling per day, and commonly underwent 60 population doublings resulting in yields of 10(8) to 10(11) cells per cm2 mucosal specimen. Moreover, these conditions successfully cultivated a buccal carcinoma cell line (SqCC/Y1) for several months. The carcinoma cells were resistant to factors that inhibited growth or induced differentiation of normal cells, i.e., transforming growth factor type beta 1, Ca2+, or serum. Karyotype analyses of SqCC/Y1 cells showed 63 to 83 chromosomes per metaphase and consistent occurrences of monosomy 1, tetrasomy 19 and 20, as well as trisomy 22, and at least 7 marker chromosomes, whereas cells obtained from non-cancerous donors were diploid. It is concluded that the similarly defined culture conditions may now be applied to study characteristics of both normal and tumorous buccal epithelial cells.

Growth-associated modifications of low-molecular-weight thiols and protein sulfhydryls in human bronchial fibroblasts

The thiol redox status of cultured human bronchial fibroblasts has been characterized at various growth conditions using thiol-reactive monobromobimane, with or without the combination of dithiotreitol, a strong reducing agent. This procedure has enabled measurement of the cellular content of reduced glutathione (GSH), total glutathione equivalents, cysteine, total cysteine equivalents, protein sulfhydryls, protein disulfides, and mixed disulfides. Passage of cells with trypsin perturbs the cellular thiol homeostasis and causes a 50% decrease in the GSH content, whereas the total cysteine content is subsequently increased severalfold during cell attachment. During subsequent culture, transient severalfold increased levels of GSH, protein-bound thiols, and protein disulfides are reached, whereas the total cysteine content gradually declines. These changes in the redox balance of both low-molecular-weight thiols and protein-bound thiols correlate with cell proliferation and mostly precede the major growth phase. When the onset of proliferation is inhibited by maintenance of cells in medium containing decreased amounts of serum, the GSH content remains significantly increased. Subsequent stimulation of growth by addition of serum results in decreased GSH levels at the onset of proliferation. In thiol-depleted medium, proliferation is also inhibited, whereas GSH levels are increased to a lesser extent than in complete medium. Exposure to buthionine sulfoximine inhibits growth, prevents GSH synthesis, and results in accumulation of total cysteine, protein-bound cysteine, and protein disulfides. For extracellular cystine, variable rates of cellular uptake correlate with the initial increase in the total cysteine content observed following subculture and with the GSH peak that precedes active proliferation. The results strongly suggest that specific fluctuations in the cellular redox balance of both free low-molecular-weight thiols and protein sulfhydryls are involved in growth regulation of normal human fibroblasts.

Reactivity of fecapentaene-12 toward thiols, DNA, and these constituents in human fibroblasts

Micromolar concentrations of fecapentaene-12, a mutagen found in human feces, decrease survival measured as colony-forming efficiency and membrane integrity of cultured human fibroblasts. Fecapentaene-12 also decreases the content of cellular free low-molecular-weight thiols including glutathione. Fecapentaene-12 reacts directly with glutathione by causing both decreased levels of free thiol and some concomitant formation of oxidized glutathione, indicating that thiol depletion is a result of both alkylation and oxidative reactions. Exposure of cells to 2 or 5 microM fecapentaene-12 causes significant amounts of DNA-interstrand cross-links and DNA-single strand breaks, respectively, whereas exposure to a higher concentration of fecapentaene-12, i.e., 10 microM, also causes significant DNA-protein cross-links. Results from the reaction of fecapentaene-12 with isolated plasmid DNA parallel the cellular pattern of DNA damage; primarily interstrand cross-links and strand breaks occur also in plasmid DNA. Taken together, these studies show that fecapentaene-12 is a potent cytotoxic and genotoxic agent which can react with cellular thiols and cause several types of DNA damage.

Cytotoxic and genotoxic effects of areca nut-related compounds in cultured human buccal epithelial cells

Because betel quid chewing has been linked to the development of oral cancer, pathobiological effects of an aqueous areca nut extract, four areca nut alkaloids (arecoline, guvacoline, guvacine, and arecaidine), and four nitrosated derivatives [N-nitrosoguvacoline, N-nitrosoguvacine, 3-(N-nitrosomethylamino)propionaldehyde and 3-(N-nitrosomethylamino)propionitrile] have been investigated using cultured human buccal epithelial cells. Areca nut extract in a dose-dependent manner decreases cell survival, vital dye accumulation, and membrane integrity, and it causes formation of both DNA single strand breaks and DNA protein cross-links. Depletion of cellular free low-molecular-weight thiols also occurs, albeit at quite toxic concentrations. Comparisons of the areca nut-related N-nitroso compounds and their precursor alkaloids, at concentrations up to 5 mM, indicate that 3-(N-nitrosomethylamino)propionaldehyde is the most potent on a molar basis to decrease both survival and thiol content and to cause significant formation of DNA single strand breaks. Arecoline, guvacoline, or N-nitrosoguvacoline decreases survival and cellular thiols, whereas arecaidine, guvacine, N-nitrosoguvacine, and 3-(N-nitrosomethylamino)propionitrile have only minor effects on these variables. Taken together, the present studies indicate that aqueous extract and, in particular, one N-nitroso compound related to areca nut, i.e., 3-(N-nitrosomethylamino)propionaldehyde, are highly cytotoxic and genotoxic to cultured human buccal epithelial cells, of potential importance in the induction of tumors in betel quid chewers.

Cardiac repolarization properties during standardized exercise test as studied by QT, QT peak and terminated T-wave intervals

Changes in QT, QT peak (QTp) and terminal T-wave, Tp-Te (QT-QTp) were studied in 11 apparently healthy subjects during and after a standardized exercise test. ECG was recorded at scalar lead positions. Averaged complexes were later analysed by computer for the different time intervals. QT and QTp decreased in parallel with increasing heart rate with a ratio QTp/QT of 0.80 +/- 0.02 at rest and 0.74 +/- 0.02 at maximal heart rate around 170. After exercise QT and QTp prolonged disproportionately slower than heart rate, reaching the relation observed during exercise only 9.5 min post exercise. Tp-Te was 75 +/- 10 ms at rest and 65 +/- 8 ms at maximal heart rate. The decrease was significant (P less than 0.001). The main part of the rate-associated shortening of the QT interval occurred in the QTp interval where it was about six to seven times larger than in the Tp-Te interval. In conclusion, QT and QTp decreased similarly with heart rate during exercise. Post exercise there was an initial slower return of these intervals to the resting state than for heart rate. Tp-Te changes were minimal.

Pathobiological effects of acrolein in cultured human bronchial epithelial cells

The ability of the highly reactive aldehyde acrolein to affect growth, membrane integrity, differentiation, and thiol status and to cause DNA damage has been studied at serum- and thiol-free conditions using cultured human bronchial epithelial cells. Acrolein markedly decreases colony survival at 3 microM whereas about 10-fold higher concentrations are required to increase membrane permeability, measured as uptake of trypan blue dye. Acrolein at micromolar concentrations also causes epithelial cells to undergo squamous differentiation as indicated by decreased clonal growth rate, dose-dependent increased formation of cross-linked envelopes, and increased cell planar surface area. Acrolein causes a marked and dose-dependent cellular depletion of total and specific free low-molecular-weight thiols as well as protein thiols. Exposure to acrolein did not cause oxidation of glutathione indicating that thiol depletion occurred by direct conjugation of reduced glutathione to acrolein without concomitant generation of active oxygen species. Furthermore, acrolein is genotoxic and causes both DNA single strand breaks and DNA protein cross-links in human bronchial epithelial cells. The results indicate that acrolein causes several cytopathic effects that relate to multistage carcinogenesis in the human bronchial epithelium.

ECG abnormalities in patients with subarachnoid haemorrhage and intracranial tumours

The incidence of and possible factors influencing ECG abnormalities were analysed in one patient group with subarachnoid haemorrhages (n = 406) and another with intracranial tumours (n = 400). The highest incidence of each ECG abnormality was always found in the patients with subarachnoid haemorrhages. In this group an ECG pattern, possibly attributable to the cerebral disease and comprising abnormalities of the T and U waves and prolongation of the Q-Tc interval, was frequently identified.

Effect of digoxin on the electrocardiogram at rest and during exercise in healthy subjects

The effect of digoxin on the electrocardiogram at rest and during and after exercise was studied in 11 healthy subjects. Exercise was performed on a heart rate-controlled bicycle ergometer with stepwise increased loads up to a heart rate of 170 beats/min. The subjects were studied after peroral intake of digoxin at 2 dose levels and after withdrawal of digoxin. Administration of digoxin induced significant ST-T depression at rest and during exercise even at the small dose (2.4 +/- 0.8 microgram/kg body weight, mean +/- standard deviation). The ST-T changes were numerically small and dose-dependent. The most pronounced ST and T depression occurred at a heart rate of 110 to 130 beats/min. At higher heart rates the ST depression was less pronounced but still statistically significant. During the first minutes after exercise no significant digitalis-induced ST-T depression was seen. This reaction is not of the type usually seen in myocardial ischemia. Fourteen days after withdrawal of the drug there were no significant digitalis-induced ST-T changes at rest or during or after exercise.

QT and QT-peak interval measurements. A methodological study in patients with subarachnoid haemorrhage compared to a reference group

To study the properties of QT and QT-peak intervals, ECGs were compared between 56 consecutive patients who were suffering from subarachnoid haemorrhage (SAH) and 50 reference subjects. The routine QTc interval was compared to the mean QTc from all of the 12 leads with identifiable U waves and to the mean QT-peakc. The interval between peak and end of T(Tp-Te) was subsequently calculated. In the reference group the mean QT-peak correlated with the mean QT (r = 0.925). The rate-dependence of the mean QT-peak was not different from that of the mean QT and showed the same correlation (r = -0.607 and -0.630, respectively). No rate-dependence for the Tp-Te interval could be demonstrated. Following SAH, ECG abnormalities were most pronounced after 8-9 days, and increased with age and the degree of cerebral dysfunction. Two patient groups, where the mean QTc of each particular patient was either below (n = 27) or above (n = 29) the reference limit, were analysed. For the group without an abnormally prolonged mean QTc, the average of the individual mean QTc was significantly longer than in the reference group. Both groups had longer mean QT-peakc intervals than the reference group. About 70% of the patients with an abnormally prolonged mean QTc also had a prolonged mean QT-peakc interval, while the rest had a prolonged Tp-Tc interval; simultaneous prolongation of these two intervals also occurred. Prolongation of the Tp-Te interval did not occur in the group without an abnormally prolonged mean QTc. Routine QTc and mean QT-peakc had sensitivities of 96% and 67% respectively, specificities of 76% and 96% and predictive values of 81% and 95%. In conclusion, the routine QTc measurements, without reference to an identified U wave, may result in falsely prolonged estimates of cardiac repolarization time. In this respect the mean QT-peakc may provide additional information. In the majority of patients the prolonged mean QTc was dependent on a disturbed rate-dependent function (prolonged mean QT-peakc) while some patients had an increased asymmetry of the repolarization process within the myocardium (prolonged Tp-Tc).

Cytotoxicity, thiol depletion and inhibition of O6-methylguanine-DNA methyltransferase by various aldehydes in cultured human bronchial fibroblasts

Lipid peroxidation aldehydes of the 4-hydroxy-alpha, beta-unsaturated type, as well as the tobacco-smoke related alpha, beta-unsaturated aldehyde, acrolein, were highly cytotoxic and decreased the intracellular thiol content in cultured human bronchial fibroblasts after treatment with micromolar concentrations. In comparison, formaldehyde and acetaldehyde were less toxic and 100- to 300-fold higher doses were required to affect cell survival or thiol levels. The unsaturated aldehydes also markedly inhibited the DNA repair enzyme O6-methylguanine-DNA methyltransferase known to have a cysteine residue in its active site, but had no effect on the activity of uracil-DNA glycosylase. Our results indicate that reactive aldehydes of either exogenous or endogenous origin have direct cytotoxic effects and may also make cells more susceptible to other toxic chemicals due to an impairment in cellular defense mechanisms, e.g., DNA repair and detoxification by systems requiring glutathione.

Effect of digoxin on physical performance in healthy man

The effect of digoxin on the maximal oxygen uptake, the heart rate reaction during submaximal and maximal bicycle exercise and the isokinetic skeletal muscle strength in the thigh was investigated in nine well-trained healthy young men. A daily dose of digoxin of 0.50 mg for 2 weeks, giving a steady state serum digoxin concentration of 1.0 +/- 0.2 nmol/l, did not significantly change maximal oxygen uptake or isokinetic muscle strength. However, the heart rate at rest and during exercise, both at submaximal and maximal levels, decreased significantly during digoxin administration.

A study of ECG abnormalities and myocardial specific enzymes in patients with subarachnoid haemorrhage

Twenty-two patients with subarachnoid haemorrhage were investigated for changes in myoglobin, total CK, CK-MB and CK-BB in serum and for the incidence of ECG abnormalities. Serial ECG's showed abnormalities in 20 patients; 15 of these had T wave changes, 15 Q-Tc prolongation, ten had S-T depression and nine U waves and in seven cases arrhythmias were found. The purpose of the study was to find out whether a relationship could be established between the ECG abnormalities and changes in serum myoglobin and enzymes. However, in no patient could myoglobin or enzyme patterns consistent with acute myocardial or cerebral damage be observed and therefore the ECG abnormalities do not seem to be related to detectable myocardial damage.

Acute portal hypertension after gastric administration of ethanol in the pig

A single gastric administration of 15 ml/kg of 40% ethanol to anesthetized pigs resulted in an increased portal venous blood pressure which increased with increasing blood alcohol levels. For the first 2 h there was no significant alteration in liver blood flow, but 3 h after the administration of ethanol, when portal blood pressure reached its highest values, liver blood flow had decreased. This was probably caused by increased hepatic vascular resistance as shown in electron thin-section phase-contrast microscopy which at this time showed marked hepatocyte swelling, narrowing of the sinusoids and platelet aggregates in small portal branches.

Effect of digoxin upon intracellular potassium in man

The effect of digoxin upon intramuscular potassium was studied by use of whole body counting and biopsy technique. Twelve healthy subjects and twelve outpatients with mild cardiac insufficiency or atrial arrhythmia were digitalised. Before and after digitalization total body potassium (TBK) was measured. Potassium concentration in muscle specimens (MK) was analysed by the neutron activation technique. Digoxin was measured in serum and in skeletal muscle tissue by radioimmunoassay, and QS2-index as a measure of the electromechanical systole. In both groups a significant decrease in TBK (P less than 0.05) and MK (P less than 0.01) was demonstrated in connection to digitalization. There was no correlation between the decrease in TBK and MK, or between the concentrations of digoxin in serum or muscle and the decrease in potassium concentration. The digoxin in serum in healthy subjects was 0.9 +/- 0.33 nmol/l and in patients 1.2 +/- 0.41 nmol/l. The digoxin in muscle was 39 +/- 10.9 nmol/kg dry weight in seven of the healthy individuals and 37 +/- 9.5 nmol/kg dry weight in nine patients. After digitalization a decrease of QS2-index was found in both groups (P less than 0.01).

Skeletal muscle digoxin concentration and its relation to serum digoxin concentration and cardiac effect in healthy man

Blood samples and skeletal muscle biopsies (m. quadriceps femoris, vastus lateralis) were taken from seven healthy subjects for analysis of serum and skeletal muscle digoxin concentrations by radioimmunoassay using a percutaneous needle biopsy technique for muscle sampling. The subjects were investigated on two digoxin dose levels and on the third day after withdrawal of digoxin. It was found that the skeletal muscle/serum digoxin ratio was significantly higher than the corresponding ratio obtained in a previous study with muscle sampling (m. rectus abdominis) from patients during open heart surgery. The present study indicates a significant correlation between the digoxin concentrations in serum and skeletal muscle as well as between cardiac effect, measured by changes in QS2I, and skeletal muscle digoxin concentration. A doubling of the digoxin dose gave a proportional increase in skeletal muscle digoxin concentration. The magnitude of the estimated half-life of skeletal muscle digoxin was the same as previously reported for serum or plasma digoxin.

Skeletal muscle digoxin concentration during digitalization and during withdrawal of digoxin treatment

Blood samples and skeletal muscle biopsies (m. quadriceps femoris, vastus lateralis) were taken from 15 patients during digitalization or during withdrawal of digoxin treatment for analysis of serum and skeletal muscle digoxin concentrations. A percutaneous needle biopsy technique was used for muscle sampling and digoxin was analysed by radioimmunoassay. During "slow" digitalization with 0.25 mg digoxin daily the skeletal muscle digoxin concentrations after 2 and 4 days were 45% (range 19%--62%; n = 3) and 78% (range 56%--92%; n= 3) respectively, of the steady state concentration (defined as the digoxin concentration after 25--40 days of treatment). After 9 and 11 days of treatment the skeletal muscle digoxin concentrations were 106% (range 84%--133%; n = 5) and 116% (range 72%--164%; n = 3) respectively, of the steady state concentration. A doubling of the digoxin dose gave a proportional increase in skeletal muscle digoxin concentration (three patients). The magnitude of the estimated half-life of skeletal muscle digoxin was the same as previously reportedly in healthy subjects. No significant correlations were found between changes in systolic time intervals and steady state serum or skeletal muscle digoxin concentrations.

Influence of vasoactive drugs on blood flow in subcutaneous tumors--an experimental study in rats

Subcutaneously implanted tumors in Wistar and Lister rats were used as a model for the study of metastatic tumor blood flow and how it is affected by vasoactive drugs. Blood flow measurements were obtained using the labelled microsphere method and the reference organ technique. Microspheres (15-micrometers) labelled with either 99Tcm or 51Cr isotopes were injected intracardially and a reference sample was drawn simultaneously at constant speed. This was performed before and after the infusion of vasoactive drugs, and (as control), saline infusion. The drugs tested (adrenaline, noradrenaline, glucagon, histamine, and vasopressin) showed profound effects on central hemodynamic parameters and on muscle and skin blood flow. The relative tumor blood flow, measured as the ratio between tumor and skin or tumor and muscle blood flow, was calculated. The results show that no enhancement of the relative tumor blood flow could be registered. In fact, a decrease in the tumor-to-muscle-blood-flow ratio was noted when noradrenaline was infused, and in the tumor-to-skin ratio when adrenaline was infused. Blood flow in subcutaneous tumors was four to five times that in muscle or skin. Tumor blood flow was also inversely related to the size of the tumor.

Fatal outcome from emergency embolization of an intrahepatic aneurysm: a case report

A 73-year-old man with a cholangiocarcinoma obstructing the hepatic duct is described. The patient was treated with percutaneous transhepatic catheter and bile duct endoprosthesis for internal drainage. This was complicated by an aneurysm of the liver, which was treated by embolization of the hepatic arteries with Gelfoam, causing an extensive liver necrosis which proved to be fatal.

Effects of catecholamines on cardiovascular response and blood flow distribution to normal tissue and liver tumors in rats

The effects of infusion of adrenaline and noradrenaline were studied in rats with intrahepatic tumors, using 99mTc-and 51Cr-labeled microspheres. The effect on general circulation, cardiac output, and tissue blood flow was pronounced, especially with infusion of noradrenaline. Studies of liver tumor perfusion in relation to surrounding liver parenchyma perfusion showed an increased tumor/liver ratio in noradrenaline-infused rats, thus indicating a preferential blood flow to the tumors induced by this drug. Adrenaline as well as 0.9% NaCl solution infusion had no effect on tumor/liver blood flow ratios. Fluorescence microscopy and monoamine determination could not reveal any noradrenaline containing nerves in the liver tumors. These experiments might suggest that the effect of intraarterial infusion with cytostatic agents might be enhanced by a simultaneously administered vasoconstrictor such as noradrenaline.

Measurements of cardiac output and organ blood flow in rats using 99Tcm labelled microspheres

The cardiac output and regional blood flow have been simultaneously determined in the anesthetized rat by using the reference organ method. 99Tcm labelled dextran 15 micron microspheres were injected in the left ventricle while simultaneously an arterial reference sample was drawn at constant known rate. The values calculated regarding cardiac output agree well with previously recorded series. Regional organ blood flow in the rat is presented as ml . min-1 . g-1 tissue and values do agree with those reported by others. The results indicate that the reference organ method can be used in the rat for the study of cardiac output and regional blood flow.

Treatment of liver cancer with regional intraarterial 5-FU infusion

The results of a retrospective three year study of forty-six patients with cancer of the liver treated with regional intraarterial infusion of 5-FU are reported. No primary mortality was noted. Oblective overall remission rate was 43 per cent. Overall median survival from onset of treatment was six months. The one year survival rate was 33 per cent and the two year survival rate 11 per cent. Patients with an objective response had a significantly prolonged survival as compared with nonresponders, especially in the colorectal group: sixteen months versus four months. Survival was not related to tumor size and involvement of the liver. During treatment 42 per cent of the patients developed extrahepatic metastases. Quality of life was improved in 63 per cent of the patients. The results indicate that infusion therapy induces reasonable response and palliation but is inadequate for the control of extrahepatic tumor growth.

Measurements of total and regional tumor blood flow and organ blood flow using 99Tcm labelled microspheres. An experimental study in rats

Cardiac output, regional tissue and arterial tumor blood flow were studied in rats, with 99Tcm labelled microspheres using a reference sample simultaneously drawn as the spheres were injected. Both cardiac output and regional blood flow can be estimated in absolute values (ml X min-1 X g-1). Cardiac output and normal tissue blood flow were not affected by tumor growth in the liver or subcutaneously. In small tumors total blood flow was inversely proportional to tumor size, a finding similar in all 3 tumors studied. A relation found in liver as well as in subcutaneously implanted tumors. Blood flow in subcutaneous tumors was greater than muscle or skin blood flow. BP sarcoma had higher blood flow than the hepatoma and the adenocarcinoma. In big tumors the peripheral blood flow was larger than that in the centre of the tumor.

Arterial changes during treatment with intrahepatic arterial infusion of 5-fluorouracil

Changes in the liver arteries ranging from minimal irregularities in occlusions and development of aneurysms were investigated in 27 patients who received intra-arterial infusion of 5-FU in the hepatic artery. Variations in the arterial caliber peripheral to the hilum of the liver were noted in 13 of the patients. Further investigation of such arterial changes may be important in controlling the growth of liver metastases.