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PubMed2005

Fluctuations in absorbance observed for photoexcited ferrocene-doped poly(methyl methacrylate) thin films containing chloroform molecules as impurities.

The time-dependent changes in absorbance in the case of ferrocene-doped poly(methyl methacrylate) thin films containing chloroform molecules have been investigated after photoexcitation in nitrogen atmosphere. Photoexcitations have been made by the monochromatic light (using Xe-source and a monochromator) in the UV range. An increase in absorbance associated with spectacular fluctuations in its value, has been noticed. The nature of the variation in the fluctuations has been studied as a function of time (duration) of photoexcitation, photoexcitation wavelength and concentration of ferrocene in the film. The observed results have been discussed considering the role of secondary reaction after photoexcitation as well as the diffusion of small chemical species in the polymer matrix.

Chloroform↗
PubMed2005

Spectrophotometric study of interaction of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone with diaza-18-crown-6 and diaza-15-crown-5 in acetonitrile and chloroform solutions.

Interactions of diaza-18-crown-6 and diaza-15-crown-5, as electron donors, with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), as an electron acceptor, have been investigated spectrophotometrically in acetonitrile and chloroform solutions. The results indicated immediate formation of an electron donor-electron acceptor complex DA: [reaction in text] which is followed by two relatively slow consecutive reactions: [reaction in text]. The pseudo-first-order rate constants for the formation of the ionic intermediate and the final product have been evaluated at various temperatures by computer fitting of the absorbance time data to appropriate equations. The formation constants of the resulting DA complexes have also been determined. The influences of both the azacrown's structure and the solvent properties on the formation of DA complexes and the rates of subsequent reactions are discussed.

Acetonitriles↗
PubMed2005

Spectra and structure of binary azeotropes I. Acetone-chloroform.

Some characteristic vibrational modes of acetone and chloroform change due to the azeotrope formation. The extend of interaction of these molecules has significant effects on some vibrational modes involved, depending on unit structure in azeotrope cluster. Besides (1)H NMR signals undergo some chemical shifts, which show the effect of oncoming molecules on the target molecule. FT-IR and (1)H NMR spectra of pure substances and corresponding azeotrope were recorded, mutual influences due to azeotrope formation based on mole ratio, boiling point and spectral changes has been discussed. Unit structure of cluster deduced by investigating fundamental frequency shifts and (1)H NMR chemical shifts.

Acetone↗
PubMed2006

A spectrophotometric and thermodynamic study of the charge-transfer complexes of iodine with 2-aminomethyl-15-crown-5 in chloroform and 1,2-dichloroethane solutions.

Interaction of 2-aminomethyl-15-crown-5 (AM15C5) with iodine has been investigated spectrophotometrically in chloroform and 1,2-dichloroethane (1,2-DCE) solutions. The observed time dependence of the charge-transfer band and subsequent formation of I(3)(-) in solution were related to the slow transformation of the initially formed 1:1 AM15C5.I(2) outer complex to an inner electron donor-acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion. The pseudo-first-order rate constants were evaluated from the absorbance- and conductivity-time data. The stoichiometry and formation constants of the resulting EDA complexes have also been determined. Thermodynamic parameters, Delta H degrees and Delta S degrees , of the complexes have been determined from the temperature dependence of stability constants by Van't Hoff equation. The results indicate that iodine complexes of AM15C5 in both solvents are enthalpy stabilized but entropy destabilized. The influence of solvent properties on the kinetics and stability of the resulting charge-transfer complexes are discussed.

Chloroform↗
PubMed2005

Radiation induced decomposition of methyl tert-butyl ether in water in presence of chloroform: kinetic modelling.

The destruction of methyl tert-butylether (MTBE) in water in the presence of chloroform has been studied using 60Co gamma irradiation. Distilled water solutions at three different concentrations of the individual solutes MTBE and CHCl3 were irradiated for various times to provide dose destruction information. Then, the irradiation of a mixture of MTBE (at two different concentrations) and CHCl3 (at one concentration) was conducted. A kinetic model was used incorporating recently determined bimolecular rate constants to describe the destruction of the MTBE and CHCl3 individually and in mixtures. These studies were conducted in distilled water simplifying the radiation chemistry significantly. With the improvements in the modelling capability, we are closer to being able to use the model to study "real-world" mixtures in natural waters.

Chloroform↗
PubMed1975

Liquid ion exchangers in paper chromatography of steoidal glucosiduronic acids. Influence of different exchangers on the mobility in chloroform-formamide and correlation of chromatographic data.

A group of 25 steroidal glucosiduronic acids was chromatographed on paper chloroform-formamide in the presence of several different liquid ion exchangers. Chromatograms were run also in three Bush-type systems. RF values were converted into RM values and the data were correlated by use of a series of regression equations of the type RM(Y) = a-RM(X) + b, in which X designates a standard system to which each other system (Y) is compared. The ratio of the slope a to the correlation coefficient r (i.e., a/r) is a measure of the resolving power of system Y relative to the standard system; intercept b, in association with slope a, is an indication of the polarity of system Y relative to X. The correlation coefficient r and the standard error of estimate sy-x are indications of whether solvent systems Y and X have very similar or relatively different resolving properties for a group of solutes. The regression equations are useful for correlating chromatographic data obtained from a group of compounds in several solvent systems. Properties of the chromatography systems are discussed and the relative importance of ion exchange and hydrogen bonding with the various solvent systems is pointed out. Delta RMg and delta RMr values are given for functional groups at several locations in the conjugates for ten of the chromatography systems.

Chloroform↗
PubMed1992

A comparison of apical seal: chloroform versus halothane-dipped gutta-percha cones.

A dye penetration study was done to compare apical leakage among three groups of extracted teeth obturated with a lateral condensation technique. In one group the master gutta-percha cones were customized in the apical portion of the canals after being dipped in chloroform. A second group used halothane as the customizing agent. No dip was used in the third group, and all three were then laterally condensed. The teeth were cleared and dye penetration was measured. Statistical analysis using a Kruskal-Wallis one-way analysis of variance of the data showed no significant difference among the groups at the p < 0.05 level.

Analysis of Variance↗
PubMed1990

Alternative solvents to chloroform for gutta-percha removal.

The purpose of this study was to evaluate new or previously identified solvents for effectiveness in dissolving gutta-percha. The solubility of a standardized weight of gutta-percha was tested in 5-ml quantities of 32 solvents. Ten samples of 30 solvents were tested at both 22 and 37 degrees C for 15 min. If the gutta-percha samples dissolved within 15 min, the times were recorded and statistically analyzed. There was no significant difference (p greater than 0.05, one-way analysis of variance and Scheffe's test) between dissolving times of chloroform and trichloroethylene at 22 and 37 degrees C. At 22 degrees C, three solvents dissolved the gutta-percha sample, whereas at 37 degrees C, nine solvents dissolved the gutta-percha. At 37 degrees C, halothane (Fluothane) was twice as effective as cineole and demonstrated many favorable working qualities. An important finding from the experimentation with halothane was the discovery of a potential obturating material, which was termed "halopercha".

Chloroform↗
PubMed1989

A comparison of apical seal: chloroform versus eucalyptol-dipped gutta-percha obturation.

Three groups of extracted teeth were obturated using gutta-percha and lateral condensation. In one group the gutta-percha was dipped in chloroform before condensation. In a second a eucalyptol dip was used. No dip was used in the third group. A dye penetration study was done to compare leakage among the three groups. The teeth were cleared for viewing and measurements of dye penetration were made using a stereomicroscope. Statistical analysis using Kruskal-Wallis one-way analysis of variance of the results showed no significant difference among test groups at the 0.05 level.

Chloroform↗
PubMed2000

A comparison between the phenol-chloroform method of RNA extraction and the QIAamp viral RNA kit in the extraction of hepatitis C and GB virus-C/hepatitis G viral RNA from serum.

Viral RNAs are detected commonly in serum by hybridization and polymerase chain reaction (PCR) methods for both clinical and research purposes. Two methods of extracting viral RNA were evaluated prior to amplification by PCR. One was a conventional phenol-chloroform method and the other used a standardized, manufactured kit. The efficiency of extraction was tested by semi-quantitative amplification of hepatitis C viral and GB virus-C/hepatitis G viral RNAs. The standarized commercial method, although more time efficient, resulted in an approximately ten fold less sensitivity. Thus, in situations where maximum sensitivity is needed, the more labor intenstive phenol choloroform method is recommended.

Chloroform↗
PubMed2002

Comparative efficacy and immunogenicity of Q fever chloroform:methanol residue (CMR) and phase I cellular (Q-Vax) vaccines in cynomolgus monkeys challenged by aerosol.

Preliminary evidence gathered in rodents and livestock suggested that a phase I chloroform:methanol residue (CMR) extracted vaccine was safe and efficacious in protecting these animals from challenge with the obligate phagolysosomal pathogen (Coxiella burnetii). Prior to the initiation of phase II studies in human volunteers, we compared, in non-human primates (Macaca fascicularis), the efficacy of CMR vaccine with Q-Vax, a licensed cellular Australian Q fever vaccine that has been demonstrated to provide complete protection in human volunteers. Vaccine efficacy was assessed by evaluating thoracic radiographs and the presence of fever and bacteremia in monkeys challenged by aerosol with Coxiella burnetii. Changes in blood chemistries, hematology, behavior and pulmonary function were also examined. CMR, whether administered in single 30 or 100 microg doses or two 30 microg subcutaneous doses, gave equivalent protection in vaccine recipients as a single 30 microg dose of Q-Vax. In addition, vaccination resulted in significant, although temporary, increases in specific antibody titers against C. burnetii phases I and II antigens. The C. burnetii CMR vaccine may be an efficacious alternative to cellular Q fever vaccines in humans.

Administration, Inhalation↗
PubMed1997

Comparative efficacy of a Coxiella burnetii chloroform:methanol residue (CMR) vaccine and a licensed cellular vaccine (Q-Vax) in rodents challenged by aerosol.

Q fever is an acute and self-limited febrile illness caused by the obligate intracellular bacterium Coxiella burnetii. While phase I cellular Q fever vaccines are efficacious in humans, vaccination of immune individuals may result in sterile abscesses and granulomas. The chloroform:methanol residue vaccine (CMR) was developed as a safer alternative. The efficacy of a licensed phase I cellular vaccine (Q-Vax) was compared with that of CMR vaccine in A/J mice and Hartley guinea pigs challenged with virulent phase I C. burnetii by aerosol. Both vaccines were efficacious. The CMR vaccine dose required to protect 50% of mice (PD50) against lethal aerosol challenge (11 LD50) was one-third of the Q-Vax dose. However, the PD50 for CMR was four times the Q-Vax dose in guinea pigs challenged by aerosol (60 LD50). It was concluded that CMR is an efficacious alternative to cellular Q fever vaccines for the prevention of Q fever.

Aerosols↗
PubMed2003

Tissue repair plays pivotal role in final outcome of liver injury following chloroform and allyl alcohol binary mixture.

The objective of this study was to evaluate the interaction profile of chloroform (CHCl(3))+allyl alcohol (AA) binary mixture (BM)-induced acute hepatotoxic response. Plasma alanine aminotransferase (ALT) was measured to assess liver injury, and 3H-thymidine (3H-T) incorporation into hepatonuclear DNA was measured as an index of liver regeneration over a time course of 0-72 h. Male Sprague-Dawley (S-D) rats received single ip injection of 5-fold dose range of CHCl(3) (74, 185 and 370 mg/kg) in corn oil (maximum 0.5 ml/kg) and 7-fold dose range of AA (5, 20 and 35 mg/kg) in distilled water simultaneously. The doses for BM were selected from individual toxicity studies of CHCl(3) alone [Int. J. Toxicol. 22 (2003) 25], and AA alone [Reg. Pharmacol. Toxicol. 19 (1999) 165]. Since the highest dose of each treatment (CHCl(3)- 740 and AA- 50 mg/kg) yielded mortality due to the suppressed tissue repair followed by liver failure, this dose was omitted for BM. The levels of CHCl(3) (30-360 min) and AA (5-60 min) were quantified in blood and liver by gas chromatography (GC). The liver injury was more than additive after BM compared to CHCl(3) alone or AA alone at highest dose combination (370+35 mg/kg), which peaked at 24 h. The augmented liver injury observed with BM was consistent with the quantitation data. Though the liver injury was higher, the greater stimulation of tissue repair kept injury from progressing, and rescued the rats from hepatic failure and death. At lower dose combinations, the liver injury was no more than additive. Results of the present study suggest that liver tissue repair, in which liver tissue lost to injury is promptly replaced, plays a pivotal role in the final outcome of liver injury after exposure to BM of CHCl(3) and AA.

Alanine Transaminase↗
PubMed2002

A comparison of Haber's rule at different ages using a physiologically based pharmacokinetic (PBPK) model for chloroform in rats.

Haber's rule as commonly interpreted in inhalation toxicology, can be stated as exposure concentration times duration equals a constant biological effect, or C x t=k. In other words, identical products of concentration and duration lead to the same effect. The goals of this paper are to develop a biological and pharmacokinetic modeling approach for chloroform, and to evaluate Haber's rule for different ages by taking into account the physiological changes due to growth and aging in rats. Three-dimensional dose-response surfaces for liver toxicity were generated for each age group of interest: adolescent, adult, and senescent rats. The three-dimensional surfaces were then characterized with a generalized description of Haber's rule for each age group. The simulations suggest that adolescent rats need higher exposure levels in order to achieve similar levels of liver damage compared to adults or senescent rats, if the comparison is made using the same exposure length. In summary, a pharmacokinetic modeling approach with a biological framework including the chemical's mode of action, was used to relate concentration, exposure duration and effect. Major advantages of this approach include: the potential ability to extrapolate to humans, the inclusion of aging in the simulations, and the ability to summarize the results using a generalized form of Haber's rule.

Administration, Inhalation↗
PubMed1997

Dichloroacetic acid pretreatment of male and female rats increases chloroform-induced hepatotoxicity.

Dichloroacetic acid (DCA) and chloroform (CHCl3) are both major by-products of drinking water chlorination and DCA increases the hepatotoxicity of CHCl3. In this study, we further characterized this effect and investigated DCA-induced alterations of CHCl3 disposition and metabolism as a possible mechanism for this interaction. Both adult male and female Sprague-Dawley rats were gavaged with three doses (09:00, 16:00 and 09:00 the next morning) of DCA (each 2.45 mmol/kg), then challenged with an i.p. injection of CHCl3 (3.12 or 9.35 mmol/kg). Hepatic damage was assessed 24 h after CHCl3 administration as increased alanine aminotransferase (ALT), ornithine carbomyl transferase (OCT) and bilirubin in plasma. In a separate experiment, rats were pretreated with DCA or were given 14CHCl3 at the same dosages. The disposition of 14C in various tissues and covalent binding of 14CHCl3-derivatives to liver proteins and lipids were determined 1 h later. CHCl3-induced hepatotoxicity was significantly more severe in DCA-pretreated groups. ALT and OCT were more markedly elevated in DCA + CHCl3 (3.12 mmol/kg) groups than NaCl +CHCl3 animals. Plasma bilirubin content was elevated only in DCA + CHCl3 groups and females were more susceptible to this effect. The responses of rats to DCA treatment were somewhat gender-different. DCA treatment increased total cytochrome P450 in females, but not in males. Hepatic glutathione concentration was elevated in males after DCA treatment, but not in females. In the present study we confirmed that DCA pretreatment potentiates the CHCl3-hepatotoxicity of both male and female rats. However, there was little evidence that DCA pretreatment significantly affected CHCl3 disposition or increased CHCl3 binding in vivo.

Animals↗
PubMed1999

Nucleic acid base-pairing and N-methylacetamide self-association in chloroform: affinity and conformation.

A recently developed computational method, 'mining minima', is used to examine the hydrogen-bonding interactions of nucleic acid base-pairs and of the N-methylacetamide homodimer in chloroform. The mining minima algorithm aggressively samples molecular conformations, identifies the most important local minima, and computes their contributions to the overall free energy of the system. Here, the CHARMM 98 parameter set is used for the potential energy and the generalized Born/surface area solvent model is used to account for the influence of the solvent. Good agreement with experiment is obtained for the non-covalent binding affinities of a series of complexes. The computational approach used here is applicable to a range of molecular systems.

Acetamides↗
PubMed1997

Cholesteryl hemisuccinate treatment protects rodents from the toxic effects of acetaminophen, adriamycin, carbon tetrachloride, chloroform and galactosamine.

In addition to its use as a stabilizer/rigidifier of membranes, cholesteryl hemisuccinate, tris salt (CS) administration has also been shown to protect rats from the hepatotoxic effects of carbon tetrachloride (CCl4). To further our understanding of the mechanism of CS cytoprotection, we examined in rats and mice the protective abilities of CS and the non-hydrolyzable ether form of CS, gamma-cholesteryloxybutyric acid, tris salt (CSE) against acetaminophen-, adriamycin-, carbon tetrachloride-, chloroform- and galactosamine-induced toxicity. The results of these studies demonstrated that CS-mediated protection is not selective for a particular species, organ system or toxic chemical. A 24-h pretreatment of both rats and mice with a single dose of CS (100mg/kg, i.p.), resulted in significant protection against the hepatotoxic effects of CCl4, CHCl3, acetaminophen and galactosamine and against the lethal (and presumably cardiotoxic) effect of adriamycin administration. Maximal CS-mediated protection was observed in experimental animals pretreated 24 h prior to the toxic insult. These data suggest that CS intervenes in a critical cellular event that is an important common pathway to toxic cell death. The mechanism of CS protection does not appear to be dependent on the inhibition of chemical bioactivation to a toxic reactive intermediate (in light of the protection observed against galactosamine hepatotoxicity). However, based on the data presented, we can not exclude the possibility that CS administration inhibits chemical bioactivation. Our findings do suggest that CS-mediated protection is dependent on the action of the intact anionic CS molecule (non-hydrolyzable CSE was as protective as CS), whose mechanism has yet to be defined.

Acetaminophen↗
PubMed2001

Bactericidal properties of the chloroform fraction from rhizomes of Aristolochia paucinervis Pomel.

The deffated chloroform fraction (APRC) obtained from the rhizomes of Aristolochia paucinervis Pomel (Aristolochiaceae) has a high bacteriostatic activity against bacterial strains like Clostridium perfringens ATCC 13124 and Enterococcus faecalis ATCC 29212. Here, we report the bactericidal activity of APRC against both strains which was evaluated by using time-to kill assays. The results showed that APRC produced an intense time-dependent bactericidal effect against C. perfringens, achieving over a 24 h-period a 5log10-unit decrease in CFU/ml at a concentration > or =1.25 x MIC. In contrast, when tested against E. faecalis, APRC exhibited a concentration-dependent killing activity at concentrations of 1.25 x MIC and 2.5 x MIC, yielding to a decrease of 1.5 and 2.5log10-unit in CFU/ml at 4 h, respectively. However, substantial regrowth of E. faecalis occurred within 24 h. Ultrastructural alterations were observed for both exposed microorganisms by scanning and transmission electron microscopy.

Anti-Bacterial Agents↗