Effects of estradiol and progesterone on epidermal growth factor concentration in plasma, bile, urine, submandibular gland and kidney of the mouse

Testosterone is known to increase epidermal growth factor (EGF) concentrations in mouse plasma and submandibular salivary gland. We tested in adult sialoadenectomized (sx) and sham-operated female and male mice our hypothesis that female sex steroids also affect EGF concentrations in fluids and tissues. In 10-day treatment estradiol-17 beta increased the EGF concentration in male urine and in (sx) female plasma. Progesterone increased the concentration in both sexes in plasma (sx mice) and in the kidneys. In contrast, progesterone decreased it in female urine.     

Human epidermal growth factor: renal production and absence from plasma

Among the unsettled questions in the physiology of human epidermal growth factor (EGF) are (1) does EGF circulate in the blood and (2) what is the source of the abundant urinary immunoreactive EGF (irEGF). Therefore, we monitored the concentration of irEGF by an ultrasensitive assay in blood plasma from 5 healthy subjects every 20 min overnight carefully avoiding activation of platelets. Detectable levels (0.8-3.7 pM) were observed in only one of the subjects, in 5 of 29 samples. In random day-time plasma samples from 18 healthy adults, EGF was undetectable (less than 0.8 pM) in 13 subjects, and in 5 subjects EGF levels ranged from 2.2 to 4.9 pM. Furthermore, in 5 patients with a tumor in a functioning kidney we measured urinary relative irEGF concentration (nmol/mmol creatinine) before and after unilateral nephrectomy. The concentration fell by approximately 50%. Our findings are consistent with (1) blood irEGF residing exclusively in platelets, and (2) urinary irEGF originating from the kidneys.     

Construction of linear GlcNAcβ1-6Galβ1-OR type oligosaccharides by partial cleavage of GlcNAcβ1-3(GlcNAcβ1-6)Galβ1-OR sequences with jack bean β-N-acetylhexosaminidase

Radiolabelled GlcNAc beta 1-3(GlcNAc beta 1-6)Gal (1), GlcNAc beta 1-3)GlcNAc beta 1-6)Gal beta 1-OCH3 (4), GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4Glc (7), and GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc (10) were cleaved partially with jack bean beta-N-acetylhexosaminidase (EC 3.2.1.30), and the digests were analysed chromatographically. All four oligosaccharides were hydrolysed faster at the (1-6) branch, than at the (1-3) branch, but a high branch specificity was observed only with the glycan 4. The saccharides 1 and 7 resembled each other in the kinetics of the enzyme-catalysed release of their two non-reducing N-acetylglucosamine units, but the glycan 10 was rather different. The partial digestions made it possible to obtain radiolabelled GlcNAc beta 1-6Gal, GlcNAc beta 1-6Gal beta 1-OCH3, GlcNAc beta 1-6Gal beta 1-4Glc, and, in particular, GlcNAc beta 1-6Gal beta 1-4GlcNAc.     

An ultrasensitive time-resolved immunofluorometric assay of human epidermal growth factor

We have developed a sandwich-type time-resolved immunofluorometric assay (TR-IFMA) for human epidermal growth factor (hEGF) in body fluids. A two-step solid-phase technique was used. The assay utilizes a polyclonal anti-hEGF attached to the solid phase, and a monoclonal anti-hEGF labeled with Europium (III) as a tracer. The sensitivity of the assay (2.5 pg/ml) is at least 20 times better than what has been achieved by radioimmunoassay (RIA), and the measuring range is much wider: 2.5-5000 pg/ml. The feasibility of TR-IFMA was tested by assaying urine containing large amounts and amniotic fluid containing small amounts (mostly undetectable by RIA) of immunoreactive hEGF. The correlation between urine hEGF concentrations (1-100 ng/ml) measured by RIA and TR-IFMA was good: r = 0.96.     

Cation permeability induced by spermine and polybrene in rat liver mitochondria

The effect of the polybasic substances Polybrene and spermine on the passive and active transport of monovalent cations in mitochondria was studied. These agents were found to stimulate the low amplitude swelling of mitochondria. Volume oscillations were induced by addition of substrate in the presence of spermine. In conditions where weak oscillations were obtained without these substances, oscillations were stimulated and their frequencies increased in the presence of Polybrene and spermine. Their effects were maximal with 100–300 moles spermine per litre and 3–5 mg Polybrene per litre. These results are discussed in relation to an interaction of the agents studied with membrane negative charges which may be important regulators of ion transport.     

Ultrastructure of synaptosomes from one-day old and adult rat brain stem

Summary The ultrastructure and protein content of the five subfractions of the crude mitochondrial fraction from the brain stem of the 1-day old and adult rat was examined. The morphological composition of the subfractions after fixation in glutaraldehyde and osmiumtetroxide in the adult rat brain stem resembled that previously reported for the whole brain; synaptosomes sedimented in a sucrose gradient in subfractions C and D. In the 1-day old rat, mature synaptosomes were found in subfractions A, B, C and D; E contained mainly free mitochondria. 80–95% of the processes in the adult and 10–30% in the 1-day old rat contained synaptic vesicles which were of four types: (1) small agranular vesicles (2) large dense core vesicles (3) large agranular vesicles (4) coated vesicles. Pre- and postsynaptic membrane thickenings were demonstrated in many nerve-ending particles. In the subfractions of the 1-day old rat the protein content was one half and the distribution resembled that in the adult. Evidently nerve endings develop faster in the brain stem than in cortical areas; a serotoninor adrenergic origin of the early synaptosomes is suggested.This study was supported by a grant from the Paulo Foundation.     

Identification of enterochromaffin cells in adjacent Epon-embedded sections at light and electron microscopic levels

Summary Methods for light and electron microscopic comparison of individual argentaffin and argyrophil enterochromaffin cells (EC) in the sheep duodenal mucosa are described. These silver procedures were applied for light microscopy to Epon-embedded sections. The adjacent sections were examined with the electron microscope. The most specific characteristics of the argentaffin and argyrophil EC in electron microscopy are highly osmiophilic cytoplasmic granules. In one cell type these granules are smaller and more roundish than in the another type. These two cell types are stainable both by the argentaffin and argyrophil reactions. No essential difference can be observed in the localization of these elements. It is suggested that both cell types belong to the enterochromaffin system. Both silver methods are also suitable for the light microscopic identification of other intestinal structures in sections adjacent to that sectioned for electron microscopy.This work was supported by a grant from the Yrjö Jahnsson Foundation, Helsinki, Finland.The electron microscopic observations were carried out in the Electron Microscope Laboratory, University of Helsinki.     

Factors Influencing the Enhancement of the Infectivity of Poliovirus Ribonucleic Acid by Diethylaminoethyl-Dextran

The enhancement by diethylaminoethyl-dextran (DEAE-D) of the infectivity of poliovirus ribonucleic acid (RNA) for cell cultures was demonstrated by infective-center as well as by plaque assays, both in nonprimate (L) and primate cell systems (MK, HeLa, LLC-MK(2)). The sensitivity of plaque assays was greatly improved by using a tris (hydroxymethyl)aminomethane-buffered synthetic medium (basal medium Eagle) and freshly confluent cell monolayers. Enhancement of nucleic acid infectivity was directly dependent on the molecular weight of the DEAE-D. Two observations bearing on the action of DEAE-D appeared important: ribonuclease activity was reduced by DEAE-D, and cells pretreated with DEAE-D remained susceptible to infection with RNA in isotonic medium. Appreciable susceptibility of the treated cells persisted for at least 2 hr; the susceptible state could be reversed at will by an application of heparin. Enhancement of nucleic acid infectivity was independent of an effect of DEAE-D on intact virus and agar inhibitors.