Identification of steroid sulfate transport processes in the human mammary gland.

Circulating hormones and local biotransformation of steroid precursors are both sources of estrogen in human mammary tissue. Estrone-3-sulfate (E(1)S) is an important estrogenic form in premenopausal women, and dehydroepiandrosterone sulfate (DHEAS) constitutes a major adrenal precursor. Membrane transport systems that govern delivery of these anionic steroid conjugates to the mammary gland were investigated. RNA was screened by RT-PCR and Northern blotting for expression of organic anion transporting polypeptide (OATP) (solute carrier family 21A) and organic anion transporter (OAT) (solute carrier family 22A) gene families. OATP-B (SLC21A9) was the major carrier expressed; OATP-D (SLC21A11) and OATP-E (SLC21A12) were less abundant. In normal sections, OATP-B immunolocalized to the myoepithelium that surrounds the ductal epithelial cells. In invasive carcinoma, ductal epithelial cells were positive. OATP-B was characterized in stable transfected Chinese hamster ovary cells. E(1)S affinity constant (K(m)) [K(m) = 5 micro mol/liter, maximum velocity (V(max)) V(max) = 777 pmol/mg.min] and DHEAS (K(m) = 9 micro mol/liter, V(max) = 85 pmol/mg.min) were substrates. The prostaglandins (PG) A(1) and PGA(2) stimulated uptake of E(1)S and DHEAS by increasing V(max) 2-fold but not changing K(m). The effect of PGA was selectively blocked by the lipophilic thiol reagent N-ethylmaleimide but not by the hydrophilic acetamido-4'(iodoacetyl)aminostilbene-2,2'-disulfonic acid, suggesting an interaction between the electrophilic cyclopentenone ring and specific cysteine residues of OATP-B.

Direct detection of ultrafast thermal transients by use of a chirped, supercontinuum white-light pulse.

An experimental technique is demonstrated that permits direct optical measurement of ultrafast material transients during a single excitation-relaxation cycle. Reflection of a linearly chirped, supercontinuum optical pulse from a gold film with changing surface temperature induced by an ultrafast pump pulse allows the thermal transients to be encoded onto the spectrum of the probe pulse. Calibrating the chirp of the probe pulse and the wavelength sensitivity of the sample permits mapping of the measured transient into the time domain. Measurements are completed over the course of 100 ps with subpicosecond time resolution. Results obtained with this technique are compared with similar measurements obtained with conventional pump-probe correlation techniques.

[Dose uncertainties in irradiation of bladder cancer with the Nd: YAG laser beam]. / Dosisunsicherheiten bei der Bestrahlung von Harnblasenkarzinomen mit Nd: YAG-Laserlicht.

By in vitro investigations with the laser set medilas 2 YAG (MBB) possible dosage insecurities were demonstrated in the radiation of urinary bladder cancers using Nd-YAG-laser light. While the endoscopic distance of e.g. 3 +/- 1 mm is accompanied by a relatively low dosage uncertainty of +/- 23%, the thermic formation of gas bubbles on the endoscopic end area, which is immersed in flush fluid, may be cause a dosage uncertainty of 80%. Help is possible by slipp off the endoscope area on the bladder wall. Uncertainties because of different tissue absorption of radiation are not taken into account.

[Computer calculations on the effect of urine components on saturation relations of calcium oxalate in the urine]. / Computerberechnungen zum Einfluss von Harnkomponenten auf die Sättigungsverhältnisse des Kalziumoxalats im Harn.

With the help of a computer program the influence of magnesium, citrate, sodium, potassium, chloride and sulfate on the activity product of calcium oxalate is examined in a synthetic and in physiological urine by varying the several parameters. Natural urine shows a significant decrease of the supersaturation of calcium oxalate by enhancing concentration of citrate. A physiological average magnesium concentration shows no effect in the sense of an increase of supersaturation antagonizing the citrate. An additional increase of the concentration of magnesium is barely effective. Citrate shows a greater effect on the decrease of supersaturation of calcium oxalate than comparable quantities of magnesium concentrations. Within the normal range of sodium chloride concentration only a slight change of the supersaturation of calcium oxalate can be observed. Sulfate has also a very slight influence in natural urine within the normal physiological range, whereas potassium does not show any effect at all.