Quantitative detection of bisphenol A and bisphenol A diglycidyl ether metabolites in human plasma by liquid chromatography–electrospray mass spectrometry

Due to the ubiquity of epoxy resin compounds and their potential role in increasing the risk for reproductive dysfunction and cancer, the need for an assessment of human exposure is urgent. Therefore, we developed a method for measuring bisphenol A (BPA) and bisphenol A diglycidyl ether (BADGE) metabolites in human blood samples using high-performance liquid chromatography–electrospray ionization mass spectrometry (LC–MS). Human blood samples were processed using enzymatic deconjugation of the glucuronides followed by a novel sample preparation procedure using a solid-phase-cartridge column. This selective analytical method permits rapid detection of the metabolites, free BPA and a hydrolysis product of BADGE (BADGE-4OH) with detection limits in the low nanogram per milliliter range (0.1 ng ml⁻¹ of BPA and 0.5 ng ml⁻¹ of BADGE-4OH). The sample extraction was achieved by Oasis HLB column on gradient elution. The recoveries of BPA and BADGE-4OH added to human plasma samples were above 70.0% with a standard deviation of less than 5.0%. This selective, sensitive and accurate method will assist in elucidating potential associations between human exposure to epoxy-based compounds and adverse health effects.     

Effect of Gibberellic Acid on the Ultrastructure and {alpha}-Amylase Activity of Aleurone Cells of Avena sativa L.

The -amylase activity and ultrastructure of aleurone cells inseeds of Avena sativa L. were studied using seed halves withembryo (embryo seeds) which had imbibed water and seed halveswithout embryo (embryo-less seeds) which had imbibed water withor without GA₃. -Amylase activity was detected in the aleurone layers of embryoseeds that had imbibed water and embryo-less seeds that hadimbibed GA₃-water. The ultrastructure of aleurone cells withdetectable -amylase activity showed marked changes in the roughsurfaced endoplasmic reticulum (rER), in the flattened sacculesforming stacks and in the aleurone grains. The progressive changesin the rER were as follows: first, the number of slender rERincreased; then, the inner space became wider and showed roundor oval profile; and finally, the rER became slender again witha reduced number of adhering ribosomes. The flattened sacculesforming stacks were appressed to the surface of aleurone grains.With time, they decreased in number and finally disappeared.In parallel with the decrease of flattened saccules, digestionof proteinaceous material inside the aleurone grains proceeded. (Received February 24, 1987; Accepted September 3, 1987)     

Effect of UV-B (290–320 nm) irradiation on growth and metabolism of cucumber cotyledons

Cucumber ( Cucumis sativus L. cv. Natsusairaku 3) seedlings were grown in a growth cabinet under UV-B (290–320 nm) irradiation (equivalent to the UV-B radiation normally incident at Tokyo, 36°N latitude, during clear sky conditions in mid-april on a weighted daily fluence basis) and a UV-B-free control condition. UV-B irradiation inhibited the growth of the cotyledons, i.e. the increase in area, and increase in fresh and dry weights of the cotyledons. The greatest inhibition rate was observed in the increase in area, causing a significant increase in specific leaf weight (the ratio of weight to area). UV-B irradiation had no significant effect on DNA and RNA contents in the cotyledons, but decreased protein content slightly. In contrast, the irradiation reduced the amounts of organic acids and soluble sugars, indicating that primary carbon metabolism was very sensitive to UV-B radiation. UV-B irradiation lowered the photosynthetic activity in the cotyledons without any effect on chlorophyll content and respiratory activity. These results indicate that UV-B radiation at the ambient level may act as a physiological stress in some UV-sensitive plants.     

Proportionality of ELF electric field-induced growth inhibition to induced membrane potential inZea mays andVicia faba roots

Summary The postulate that 60-Hz electric field-induced bioeffect severity is proportional to induced transmembrane potential [ ] magnitude was tested and supported using a plant root model cell system. Statistically significant correlations were obtained upon regression of the relative rates of exposedVicia faba andZea mays root segment growth on the average (calculated) arising in those segments under specified 60 Hz field exposure conditions. The associated with the apparent threshold for growth inhibition was similar inZea andVicia roots (2.5 vs 2.4 mV, respectively). At greater than this threshold,Zea root growth declined by about 9% per mV, andVicia root growth by about 19% per mV induced potential.Abbreviations EF electric field - RGR relative growth rate - RSGR relative segmental growth rate - induced membrane potential - segmental-average induced membrane potential - VC _d region of root tip in which a complete, nascent vascular cylinder is first distinguishable in histological sections     

Correction of inverted nipple with periductal fibrous flaps.

I devised a method to correct the inverted nipple considering the preservation of the lactiferous ducts, sensory fibers to the nipple, and the contracting function of the areolar muscle. Excision of the excess skin at the base of the nipple was done in three diamonds fashion, and they were located at 2, 6, and 10 o'clock positions not to jeopardize the sensory fibers to the nipple. To release the fastened nipple, the periductal fibrous tissue was thoroughly dissected and made into three flaps pedicled inferiorly. These three flaps were sutured to the dermis of the periareolar skin to pull up the nipple base by means of traction in three directions. The purse-string suture, the dermal stitch on the shorter diagonals of the diamond-shaped defects, anchors the skin-muscle bridges caught at the base of the ductal column, makes the nipple base narrower, obtains stable anchoring, helps the areolar muscle contraction to resume, and prevents the recurrence of the inversion. The use of the periductal tissue as flaps to bring in areolar skin for easier anchoring and for more prominent eversion of the nipple has not been described in the literature.     

Inactivation and sedimentation of mercury from organomercurials by Klebsiella pneumoniae

Abstract A susceptibility of 63 clinical isolates of Klebsiella pneumoniae to inorganic and organic mercuric compounds was determined. 18 of them were found to be resistant to fluorescein mercuric acetate (FMA) and merbromin (MB). Moreover, all the resistant strains inactivate the antibacterial effect of FMA. The changes in the amount of organic mercury at the time of inactivation of the drug and the structures of the end products were examined in detail with the plasmid-bearing strain JK9 and its transconjugants of Escherichia coli .
The results showed that FMA was inactivated by an intracellular enzyme produced inducively and was degraded to fluorescein (sodium salt, uranine), which led to the sedimentation of metallic mercury. The discovery of the genes conferring inducible organic mercury-inactivating enzymes determined by plasmids was the next step and their application in the recovery of metallic mercury from organomercurials is now imminent.     

Determination of the complete nucleotide sequence of pNS1, a staphylococcal tetracycline-resistance plasmid propagated in Bacillus subtilis

Abstract The complete nucleotide sequence of pNS1 (3879 bp), a tetracycline-resistance (Tc^R) plasmid drived from staphylococcal plasmid pTP5, has been determined and compared with that of the staphylococcal Tc^R plasmid pT181 [6]. The nucleotide sequences of the 2 plasmids are in agreement, except for 18 nucleotides, but these differences are significant in that they give rise to new open reading frames (ORFs). A short ORF-D is found in the copy control region, and the Tc^R region contains a single large ORF-A, that encodes the Tet protein (50 kDa). The upstream region of ORF-A contains 3 inverted repeat sequences, which can generate structures very similar in conformation of the structure of the control region of the inducible erythromycin-resistance gene of pE194.     

Uptake of Neutral Red by the Vacuoles of a Green Alga, Micrasterias pinnatifida

Neutral red (NR) in the culture medium entered the vacuolesof a green alga, Micrasterias pinnatifida, at a higher rateat pH 8 than at pH 5. NR remained soluble in vacuoles of cellscultured at pH 5, while it precipitated and formed granulesin cells cultured at pH 8. The vacuoles of cells cultured atpH 8 contained fibrils, but those of cells cultured at pH 5did not. The amount of NR that entered the cells was markedlyreduced by the addition to the medium of nigericin at 10^-5M,monensin at 10^-5M, bafilo-mycin A₁ at 10^-5M, or ammonium chlorideat 50 mM. The formation of NR granules in vacuoles were stronglyinhibited and the disorganization of NR granules were acceleratedby the addition of nigericin at 10^-5M, or bafilomycin A₁ at10^-5M to the culture medium. The possibility is discussed thatNR which enters vacuoles might become positively charged (NRH⁺)by protons brought into vacuoles by proton pumps and that NRH⁺might combine with some negatively charged macromolecules toform aggregates or granules. (Received April 18, 1996; Accepted May 27, 1996)