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Query: CAS:142-82-5 (heptane)
 3,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

New tris(beta-diketonato) complexes of trivalent 99Tc/99mTc with the ligands hexane-2,4-dione, heptane-2,4-dione, heptane-3,5-dione, and octane-3,5-dione were synthesized by reduction of pertechnetate with dithionite in the presence of excess beta-diketone. The complexes were purified by HPLC, identified by elemental analysis and FAB mass spectrometry, and characterized by vis./u.v./i.r. spectrophotometry. The hexane-2,4-dionato complex crystallizes in the monoclinic space group P21/c, isostructurally with pentane-2,4-dionatotechnetium(III). Biodistribution measurements in mice showed the neutral and lipophilic 99mTc-diketonato complexes to penetrate the blood-brain barrier. However, increasing lipophilicity decreased the brain uptake except for the heptane-2,4-dionato complex, which displayed the highest uptake of 0.82% injected dose/g.
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PMID:Synthesis, characterization and biodistribution of tris(beta-diketonato)technetium(III) complexes. 157 15

Because of waxes in the vitelline membrane, the Drosophila egg is effectively impermeable to liquid water and to aqueous solutes, and consequently it cannot be cryopreserved unless it can be permeabilized. The more successful of the few published permeabilization procedures involve the removal of the chorion mechanically or by hypochlorite solution, the removal of all surrounding water by air drying or alcohol, the exposure of eggs to pure alkanes like octane or hexane for some 30 s, the removal of the alkane and the transfer of the eggs to aqueous culture medium without their desiccation, and lastly incubation of the permeabilized embryos under mineral oil. In following these procedures we opted for a somewhat different approach to applying hypochlorite, water, alcohol, and alkane; namely, eggs were placed between two Nucleopore filters, and the fluids drawn sequentially through the filters by vacuum. Extensive initial attempts were mystifying and discouraging in that although permeabilization was good, survivals were poor, and modifications that increased the latter reduced the former. The explanation turned out to be that permeabilization and survival depended critically on the amount of carry-over alcohol that contaminated the alkane. To determine the effects of alcohol concentration in the alkane, it was essential first to effectively eliminate carry-over contamination and then re-add precise amounts of alcohol (isopropanol) to the alkane (n-hexane, heptane, or octane). When the alcohol concentration is less than or equal to 0.2%, permeabilization is poor; when it is greater than or equal to 0.5%, permeabilization is good but survival (hatching) is poor. There are strong interactions between alcohol concentration and exposure time to alkane/alcohol mixtures with respect to the fraction of embryos that become permeabilized and the percentage that survive. There are also significant but less critical effects from the type of alcohol and alkane. The best results for 12-h embryos (greater than or equal to 90% permeabilization and 70-80% hatching) were achieved with eggs exposed to 0.3 or 0.4% 1-butanol in n-heptane for 90 s. High survivals of permeabilized 12-h embryos did not require incubation under mineral oil. Permeabilized embryos are permeable to water, ethylene glycol, glycerol, and the stain rhodamine B (which was used to assess permeabilization). They are effectively impermeable to sucrose. Embryo age is important. Between 14 and 16 h the above permeabilization procedures become dramatically less effective.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Critical factors affecting the permeabilization of Drosophila embryos by alkanes. 158 29

Using quin2, the effects of aliphatic hydrocarbons on the system of Ca(2+)-induced Ca2+ release in isolated membranes of rabbit skeletal muscle terminal cisterns have been studied. The hydrocarbons were inserted into the membranes by means of hydrocarbon-containing liposomes. 2,2,4-Trimethylpentane (isooctane) caused a rapid release of 70-75% of Ca2+ taken up by the terminal cistern vesicles during the Ca(2+)-pump operation. This effect was inhibited by the caffeine-induced Ca2+ release blockers--Mg2+, ruthenium red and tetracaine. The same was observed with a decrease in the concentration of ATP that is known to activate the terminal cistern Ca2+ channels. The effect of 2,2,4-trimethylpentane on the longitudinal cistern fractions practically devoid of Ca(2+)-channels was insignificant. Heptane, hexane and octane caused a slow release of 5-10% of the accumulated Ca2+ from the terminal cistern vesicles; no such effect was induced by decane.
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PMID:2,2,4-Trimethylpentane induces Ca2+ release from the sarcoplasmic reticulum terminal cisterns. 171 88

The purpose of the present study was to see if chemically sensitive individuals had aliphatic hydrocarbon solvents as part of their total body load. This was done by measuring blood levels from 85 chemically sensitive patients. These were measured by a purging trap method with gas chromatography/mass spectrometry (GCC/MS) by the methods of Laseter. Thirteen patients had blood levels below the detection limit of less than 1 ppb and 72 were above the detection limit. An average of three solvents, out of seven measured, including n-pentane, 2,2-dimethylbutane, cyclopentane, 2-methylpentane, 3-methylpentane, n-hexane, n-heptane, was found in 85% of the patients' blood on the 1 to 299 ppb range. The means were as follows: n-pentane 14.7 ppb, 2,2-dimethylbutane 2.5 ppb, cyclopentane 9.0 ppb, 2-methylpentane 16.7 ppb, 3-methylpentane 28.0 ppb, n-heptane 5.5 ppb. The most frequently found of the above solvents was 2-methylpentane (found in 68.1% of the patients), 3-methylpentane (62.5%), n-hexane (61.1%), and pentane (40.3%).
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PMID:Aliphatic hydrocarbon solvents in chemically sensitive patients. 181 10

Extractive ultrafiltration is a separation process by which liquid extraction in series with ultrafiltration removes contaminants from water. The toxin is extracted into an organic-in-water emulsion which is then separated by an ultrafilter. The ultrafilter thus replaces the settler in a conventional mixer-settler process; the extraction and emulsification allow ultrafiltration to remove much smaller molecules than is indicated by the nominal molecular weight cut-off of the membrane. In the present study, the toxins, toluene and monochlorobenzene, were individually extracted from water into heptane and hexane, respectively, reducing their concentration in the permeate water five to ten fold, at fluxes in excess of 60% of the pure water flux for the membrane. The operating temperature, organic to water ratio, and amount of surfactant used to stabilize the emulsion, were independently varied to determine the optimum values of each quantity, consistent with highest possible permeate flux through the membrane and maximum removal of the contaminant. General conclusions drawn were that the optimum permeate was obtained 1. at ambient temperature 2. when surfactant concentration was a minimum 3. when a minimum amount of extraction solvent was used.
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PMID:Extractive ultrafiltration. 272

Hepatotoxic effects of n-hexane and n-heptane administered i.p. (1 ml/kg body wt) were studied in albino rats after 1, 2, 7 and 45 days of treatment. Hepatic protein content decreased with n-heptane and total sulphydryl content showed a significant decrease in the rats exposed to either solvent. A significant increase in lipid peroxidation was observed after 24 h and 48 h exposure to n-hexane or n-heptane. A marked decrease in drug metabolizing activity and an increase in pentabarbitone sleeping time was also observed. Hepatic glucose-6-phosphatase, a microsomal marker enzyme, showed a significant decrease.
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PMID:Hepatotoxic effects elicited by n-hexane or n-heptane. 283 4

A sensitive high-performance thin-layer chromatographic (HPTLC) procedure for the detection of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), the major urinary metabolite of delta 9-tetrahydrocannabinol (THC), is described. After alkaline hydrolysis, the THC-COOH is extracted from acidified urine into hexane. The hexane is evaporated and the residue spotted onto an HPTLC plate. Chromatography time is 11 min with heptane/butanol/acetic acid (90:9:1) as mobile phase. The cannabinoids are visualized by sequentially dipping the thin-layer plate in diethylamine then in 0.1% Fast Blue BB. The limit of detection for THC-COOH is 5 ng/mL when 2 mL of urine is used. Extraction efficiencies averaged 71% over the 10-400 ng/mL range. No drugs, drug metabolites, or endogenous urinary substances interfere with the procedure.
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PMID:A sensitive thin-layer chromatographic procedure for the detection of urinary 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid. 283 84

Existing methods for the identification of mammalian fecal particles in foods have not been completely satisfactory because visual identification of small particles is difficult. In addition, identification of feces by determining the presence of fecal alkaline phosphatase is limited to specimens in which the enzyme has not been inactivated, and it does not work well with feces from herbivores. A new method has been developed which uses coprostanol as a fecal indicator. Coprostanol is a heat-stable sterol found in the feces of mammals and some birds. A hexane extract of the suspect particle is applied to the preadsorbent zone of a silica gel thin layer chromatography plate which has been impregnated with 5% phosphomolybdic acid in ethanol. The plate is developed in diethyl ether-heptane (55 + 45), heated, and examined visually for the presence of coprostanol. Amounts of rat feces as small as 0.15 mg and cow feces as small as 0.5 mg have been identified using this method.
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PMID:Identification of mammalian feces by coprostanol thin layer chromatography: method development. 311 14

Methods for measuring the hydroxyl-, ozone-, and direct photochemical reactivity of a substance in one specially designed medium size smog chamber are described. Rate coefficients for the reaction of OH with n-hexane, n-heptane, ethene, ethyne, chloroform, trichloroethene, methanol, 2-propanol, benzene, o-xylene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, p-chloroaniline, naphthalene, acenaphthene, 1,4-dichloronaphthalene, biphenyl, and fluorenone are given and discussed. An upper limit of 5 X 10(-13) cm3/sec is given for the sum penta- and hexa-chlorobiphenyls (PCB). Rate coefficients for the ozone reaction are given for beta-pinene, limonene, delta 3-carene, cineol, vinyl chloride and 1,3-butadiene. In cases where the literature data are available for comparison, the rate coefficients (kappa OH and kappa O3) reported here compare favorably with the best data reported. The direct photochemical reactivity has been shown to be measurable if the chamber is cleaned carefully. Preliminary results on benzophenone are reported. The methods described here, except that of direct photochemical reactivity, are in agreement with those proposed to OECD. Moreover, part of the Draft OECD Test Guideline (Berlin, 1987) on "Photochemical-Oxidative Degradation in the Atmosphere" is based on work described here and on closely related work in other laboratories (Becker et al., 1984).
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PMID:Testing of the abiotic degradation of chemicals in the atmosphere: the smog chamber approach. 316 77

A gas chromatographic method using nitrogen-selective detection for the quantitative determination of nanogram amounts of chlorimipramine, chlorpromazine and their nor1 and nor2 derivatives in plasma is described. Derivatization with trifluoroacetic anhydride of nor1 and nor2 metabolites allowed the chromatographic separation of these compounds. A three-step solvent extraction procedure was performed using n-heptane containing 1% isoamyl alcohol and n-hexane and compared with a plasma clean-up procedure using C18 Sep-Pak cartridges. The two procedures were characterized by similar degrees of precision. The use of C18 Sep-Pak cartridges, however, produced a significant time and material saving over the conventional extraction method.
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PMID:Isothermal gas chromatographic determination of nanogram amounts of chlorimipramine, chlorpromazine and their N-desmethyl metabolites in plasma using nitrogen-selective detection. 376 89


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