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J Whitney

Publications and source records attributed to J Whitney.

12 recordsLinked to original sources
PubMed1991

Vanillin, a potential agent for the treatment of sickle cell anemia.

Vanillin, a food additive, has been evaluated as a potential agent to treat sickle cell anemia. Earlier studies indicated that vanillin had moderate antisickling activity when compared with other aldehydes. We have determined by high performance liquid chromatography that vanillin reacts covalently with sickle hemoglobin (HbS) both in solution and in intact red blood cells. Hemoscan oxygen equilibrium curves show a dose-dependent left shift, particularly at low oxygen tensions. Rheologic evaluation (pO2 scan Ektacytometry) of vanillin-reacted HbS erythrocytes shows a dose-dependent inhibition of deoxygenation-induced cell sickling. Ektacytometry also suggests that vanillin may have a direct inhibitory effect on HbS polymer formation. Vanillin has no adverse effects on cell ion or water content. X-ray crystallographic studies with deoxyhemoglobin (HbA)-vanillin demonstrate that vanillin binds near His 103 alpha, Cys 104 alpha, and Gln 131 beta in the central water cavity. A secondary binding site is located between His 116 beta and His 117 beta. His 116 beta has been implicated as a polymer contact residue. Oxygen equilibrium, ektacytometry, and x-ray studies indicate that vanillin may be acting to decrease HbS polymerization by a dual mechanism of action; allosteric modulation to a high-affinity HbS molecule and by stereospecific inhibition of T state HbS polymerization. Because vanillin is a food additive on the GRAS (generally regarded as safe) list, and because it has little or no adverse effects at high dosages in animals, vanillin is a candidate for further evaluation as an agent for the treatment of sickle cell disease.

Anemia, Sickle Cell↗
PubMed1991

Temperature cycler evaluation: what do you need to know?

Which of the 20 different, commercially available, temperature cyclers adequately fulfill all functional requirements? How can an investigator analyze instrument function? This report describes in detail, for the first time, the characteristics of Ericomp temperature cyclers. The data show that the temperature uniformity, accuracy and maximum overshoot is +/- 0.34 degree C, less than 0.5 degree C and 0.17 degree C, respectively. Cycling temperature reproducibility is 0.1%, and cycling time reproducibility is 0.4%. These data compare very favourably to published data describing other temperature cyclers. The techniques used to obtain these data serve as a model for evaluating instruments for well-to-well uniformity, temperature accuracy and within-run reproducibility.

Biotechnology↗
PubMed1990

Surface electrical stimulation versus brace in treatment of idiopathic scoliosis.

Surface electrical stimulation using the ScoliTron device was applied to 40 adolescent patients for treatment of idiopathic scoliosis. Adequate follow-up was available for 30 of these patients. The overall failure rate was 15 of 30 or 50%. Due to curve progression while using the ScoliTron, these patients either went on to a fusion (9 of 15) or were changed to a brace (6 of 15). The remaining 15 patients were considered successes with no curve progression (10 of 30 or 33%) or successful/failures with slight curve progression not requiring a change in treatment (5 of 30 or 17%). None of the various parameters analyzed were found to be useful indicators of successful treatment using the ScoliTron device. Electrical stimulation was found to be ineffective in preventing curve progression for idiopathic scoliosis.

Adolescent↗
PubMed1986

Fast atom bombardment combined with tandem mass spectrometry for determination of bile salts and their conjugates.

Fast atom bombardment desorption of bile salts produces negative ions which show little fragmentation. The lack of fragmentation limits the utility of the method for resolving questions regarding specific structural features. This paper is a report of negative ion fast atom bombardment mass spectra and collision-activated decomposition spectra of cholate, chenodeoxycholate, lithocholate, taurocholate, taurochenodeoxycholate, taurolithocholate, 3 beta-ol-5-cholenate, taurolithocholate-3-sulfate and glycolithocholate-3-sulfate. The collision-activated decomposition spectra are useful for distinguishing bile salt structural features and for quantifying relative amounts of isomeric ions in a mixture. The negative ion mode is well suited for generating anions of bile salts and, when coupled with collisional activation, provides complementary information to the positive ion mode. The collision-activated fragmentation is also unusual as it appears to be an example of reactions occurring remote from the charge site. Furthermore, on the basis of the fragmentations, the charge site can be located in the amphiprotic form of some gas-phase diprotic bile acids such as taurolithocholate-3-sulfate and glycolithocholate-3-sulfate.

Bile Acids and Salts↗
PubMed1985

In vitro synthesis of vitamin D-3 by cultured human keratinocytes and fibroblasts: action spectrum and effect of AY-9944.

With delineation of the photochemical events occurring in the skin after ultraviolet exposure, there has been increased interest in the skin's role in the vitamin D-3-endocrine system. We provide here in vitro conditions for the generation of both labelled (from [3H]acetate) and unlabelled vitamin D-3 in cultures of human keratinocytes and fibroblasts. Sterol precursors and photoproducts in irradiated and non-irradiated cultures are identified by co-chromatography, ultraviolet absorbance spectra, thermal conversion characteristics of previtamin D-3 and mass spectrometry. Because the conversion of 7-dehydrocholesterol to cholesterol is more efficient in vitro than in vivo, the specific delta 7 inhibitor, AY-9944, was added in non-toxic doses to modulate 7-dehydrocholesterol content. Both cell types were equally capable of generating photoproducts, depending on the amount of 7-dehydrocholesterol present. The 290 +/- 5 and 295 nm filters were much more efficient than the 305 nm filter for generating previtamin D-3 and vitamin D-3 in fibroblasts. In contrast, the 305 nm filter was as efficient as the 290 +/- 5 and 295 nm filters in keratinocytes, where it yielded previtamin D-3, with much less lumisterol and tachysterol than appeared with the shorter-wavelength filters. The amount of lumisterol and tachysterol versus previtamin D-3 formed in both cell types was dependent on the total energy applied, with lower energies (less then 1 J/cm2) favoring previtamin D-3 over the other photoproducts. The use of cultured cells provides a system whereby the regulation of vitamin D-3 synthesis by extracutaneous factors can be studied in a homogeneous setting.

Aldehyde Oxidoreductases↗
PubMed1978

Preparation and efficacy of an inactivated subunit vaccine (NFUIBHK) against type 2 Herpes simplex virus infection.

A vaccine against Herpes simplex virus infection was prepared by Nonidet NP 40 and formalin treatment of a type 1, infected-cell extract; virus particles were removed by ultracentrifugation over sucrose. These procedures were not detrimental to the antigenic quality of the vaccine preparation. The vaccine afforded significant protection to experimental type 2 genital herpes virus infection in mice, as adjudged by clinical observations, cytopathological change, and virus yields.

Animals↗