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T L Jones

Publications and source records attributed to T L Jones.

88 records · Page 5Linked to original sources
PubMed1988

Environmental semivolatiles and nonvolatiles analysis by hyphenated spectral techniques.

Environmental sample extracts contain a variety of volatile and nonvolatile organic compounds exhibiting a range of polarities and concentrations. Although gas chromatography/mass spectrometry (GC/MS) is the method of choice thus far for such analyses, this technique used alone cannot adequately characterize the volatiles in such samples and is not amenable to environmental nonvolatiles. A more complete characterization of environmental and hazardous waste samples is required to assess the dangers posed to the nation's groundwater by hazardous waste dumps. Online spectral confirmation by directly linked GC/Fourier transform infrared (FTIR)/MS is shown to provide useful structural information on environmental volatiles in hazardous wastes, even when the analyte's spectrum is not in either spectral database. This information can lead to biological-hazard estimation. The diffuse reflectance Fourier transform infrared (DRIFT) technique, used in conjunction with thermospray MS or fast atom bombardment (FAB) MS, provides confirmed identifications or confirmed compound class assignments of organic nonvolatiles in solid wastes. This is believed to be the first report of spectral confirmation (identification or functionality) of organic volatiles and nonvolatiles in environmental samples.

Air Pollutants↗
PubMed1986

Evaluation of a new triphasic oral contraceptive in private practice.

We evaluated the clinical and metabolic effects of a new triphasic regimen developed in the continuing attempt to reduce the dose of estrogen and progestogen in oral contraceptives. A combination of ethinyl estradiol (EE) and levonorgestrel (LNg) was used (six tablets with 30 micrograms EE + 50 micrograms LNg, five tablets with 40 micrograms EE + 75 micrograms LNg, and 10 tablets with 30 micrograms EE + 125 micrograms LNg), also known as Triphasil (Wyeth). In a private practice, 409 subjects participated in 7,286 treatment cycles. Three pregnancies occurred, all due to subject failure. Menstrual regulation was excellent and the incidence of side effects extremely low. Withdrawals from the study for possibly drug-related medical reasons totaled 9.0% through 56 cycles of treatment. Metabolic changes also were evaluated in 14 of these women over a 6-month period. The only statistically significant increase in carbohydrate values occurred at 6 months. The mean glucose level at 30 minutes of the oral glucose tolerance test was above the baseline mean value, but serum insulin levels showed no statistically significant deviation. Lipid values presented are total lipids, total cholesterol, triglycerides, alpha-, beta-, and pre-beta-lipoproteins, and high density and low density lipoprotein cholesterol. There was no statistically significant difference between the mean values at baseline and those during treatment for any lipid variable. These results indicate that this triphasic oral contraceptive has a high degree of efficacy, a low incidence of side effects, excellent cycle control, and high subject compliance, and would seem to indicate a minimal influence on the metabolism of lipids and carbohydrates in the small number of subjects studied.

Blood Glucose↗
PubMed1983

Susceptibilities of cardiac myofibrillar proteins to cathepsin D-catalyzed degradation.

The binding of various myofibrillar proteins to cathepsin D and consequent susceptibility to degradation was assessed by determination of apparent Michaelis constant (Km) values for the purified enzyme using myosin, alpha-actinin, actin, and tropomyosin as substrates. Cathepsin D, purified 1,000-fold to homogeneity from canine cardiac tissue, was incubated (0-100 min at 37 degrees C) with myofibrillar proteins isolated from homologous tissue and labeled radioactively with 14C by reductive alkylation. The reaction was terminated by addition of trichloroacetic acid (10% wt/vol), and radioactivity in the supernatant fraction was determined after centrifugation (5 min) at 100,000 g. Double reciprocal graphs (1/reaction velocity vs. 1/substrate concn) were constructed for each substrate from the linear portion of graphs of disintegrations. min-1 X ml-1 100,000-g supernatant vs. time (min). Apparent Km values (+/- SD) calculated for myosin, alpha-actinin, actin, and tropomyosin were found to be 2.7 +/- 0.3 X 10(-6) (n = 6), 10.0 +/- 2.3 X 10(-6) (n = 13), 13.0 +/- 1.3 X 10(-6) (n = 7), and 45.5 +/- 9.0 X 10(-6) (n = 6) mol/l, respectively. The results show that myofibrillar proteins differ in their binding and thus susceptibility to hydrolysis by cathepsin D in order of molecular weight (i.e., myosin greater than alpha-actinin greater than actin greater than tropomyosin). Because the relative turnover rates of myofibrillar proteins are known to be independent of molecular weight, our results suggest that the degradation of these proteins by cathepsin D is not rate limiting and that other factors including lysosomal or nonlysosomal enzymes must determine the rate-limiting steps of myofibrillar protein degradation in cardiac tissue.

Actinin↗
PubMed1980

A rapid method for assessment of a macrophage chemotactant produced by SaD2 fibrosarcoma cells in vitro.

A new rapid method for assessing murine macrophage chemotaxis was developed using peritoneal exudate cells labeled with [5,6-3H]uridine in modified Boyden chambers with double polycarbonate filters. The method gave positive results with endotoxin-treated mouse serum and with serum-free culture supernatant of the DBA/2 SaD2 fibrosarcoma. These results correlated with results obtained with conventional microscopic assessment of chemotaxis. Using this method, the SaD2 supernatant was shown to be chemotactic rather than chemokinetic.

Animals↗
PubMed1976

Inhibition of parental tumor colony formation by cells from a semi allogeneic mixed spleen cell reaction.

Cells capable of inhibiting colony formation by the DBA/2 fibrosarcoma SaD2-AG and mammary adenocarcinoma CaD2 are generated in vitro during semiallogeneic histoincompatibility reactions between DBA/2 and (C3H/He X DBA/2)F1 hybrid spleen cells. These colony-inhibiting cells adhere strongly to plastic, develop from nonadherent precursors, and retain colony-inhibiting ability even after receiving 5,000 rads of ionizing radiation.

Adenocarcinoma↗
PubMed1972

Electron paramagnetic resonance of nitrogenase and nitrogenase components from Clostridium pasteurianum W5 and Azotobacter vinelandii OP.

The electron paramagnetic resonance of nitrogenase components, separately and together with the other reactants in the nitrogenase system (namely, reductant and Mg.ATP), have been examined at low temperatures (<20 degrees K). The MoFe protein, component I or molybdoferredoxin, in the oxidized (but not oxygen-inactivated) state yields signals with g-values of 4.3, 3.7, and 2.01, and when reduced has no observable electron paramagnetic resonance. The Fe protein, component II, or azoferredoxin, yields a signal with g-values of 2.05, 1.94, and 1.89 in the reduced state that is converted by Mg.ATP into an axial signal with g-values near 2.05 and 1.94, and a second split signal near g = 4.3. The Fe protein has no definite electron paramagnetic resonance in the oxidized (not oxygen-denatured) state under these conditions. The Mg.ATP complex of reduced Fe protein reduces the MoFe protein, whereas dithionite alone does not reduce the MoFe protein. Reoxidation of the system by substrate leads to disappearance of the Fe protein signal and the reappearance of the MoFe protein signal. Thus Mg.ATP, which is hydrolyzed during substrate reduction, converts the Fe protein to a reductant capable of transferring electrons to MoFe protein, after which substrate reduction occurs.

Adenosine Triphosphate↗
PubMedDate not supplied

Separation and detection of three aryltins by capillary electrophoresis-UV/VIS diode array.

The trialkyltins and triphenyltins have widespread application as fungicides, antifouling coatings for porous surfaces, herbicides, insecticides, and generic biocides. Due to the varied toxicity of each species of organotins, it is important that methods address the speciation of the organotins. Traditional methods call for the hydrolysis and subsequent derivatization of the organotins before analysis. These methods can be time consuming, derivatization can be incomplete, and high levels of background interference produce difficulties in identification and quantitation. The U.S. Environmental Protection Agency's (U.S. EPA) current methods do not address the speciation of organotins; instead they only analyze for total tin. It is important, because of the differing levels of toxicity of the various congeners of organotins, to speciate them from each other and inorganic tin. The research reported in this paper addresses the use of CE with UV/VIS diode-array detection to separate and detect three phenyltins (i.e., tri-, di-, and mono-), without the need to either derivatize or complex them.

Electrophoresis, Capillary↗