The influence of some prostaglandins on DNA synthesis and DNA excision repair in mouse spleen cells in vitro

$\text{In vitro}$ experiments were performed on mouse spleen cells to establish possible influences of some naturally occurring prostaglandins on DNA synthesis and DNA excision repair. The prostaglandins A₁, B₁, E₁, E₂ and F₂ were tested in concentrations of lopg, 5ng and 2.5μg per ml cell suspension. DNA synthesis was significantly increased by pgF_2α in all the three concentrations tested, while the other tested prostaglandins were essentially ineffective. DNA excision repair was significantly inhibited by PgF₁ and PgF₂ at 5ng/'ml and at 2.5μg/ml but increased by PgF_2α in the two lower concentrations. The rejoining of DNA-strand breaks after γ-irradiation was slightly reduced by PgF₁, PgE₂ and PgF_2α at 2.5μg/ml.     

Beobachtungen zur Flugbalz der Waldschnepfe(Scolopax rusticola)

Zusammenfassung Durchgehende Beobachtungen der Balz in einem niedersächsischen Brutrevier der Waldschnepfe boten 1974 die Möglichkeit, den Verlauf der Balzsaison und die Rolle der Balzflüge der im Zusammenhang mit dem Brutgeschehen zu untersuchen. 1972 und 1973 konnte die Flugbalz in verschiedenen anderen Gebieten Niedersachsens beobachtet werden. Die ersten Schnepfen wurden 1973 und 1974 in der zweiten Märzpentade beobachtet. 1974 fand Zug bis Ende April statt.Die Balz wurde von den nach der Zugzeit ohne Unterbrechung fortgeführt. Die höchste Balzintensität morgens und abends wurde im Juni registriert.Die Balz begann morgens stets bei gleicher Lichtintensität, abends erschienen die ersten Schnepfen ab Anfang Mai bereits vor Sonnenuntergang und bei viel höherer Lichtintensität als im März und April. Die Balzpause am Tage und in der Nacht war sehr gut positiv mit der Tages- und Nachtlänge korreliert.Ein auffälliges Zeitmuster kennzeichnet die Balzphasen. Während der Unterbrechungen der Balzflüge landeten die und suchten Nahrung. Die normale Lautäußerung der war eine regelmäßig wiederholte Balzstrophe aus drei Elementen mit häufigen Abweichungen (Tab. 1).Die Balzflüge der dienten hauptsächlich dem Finden von paarungsbereiten . Während bisher angenommen wurde, die Paarfindung erfolge ausschließlich akustisch, konnte beobachtet werden, daß die auch auf optischem Wege versuchen, zu finden. Wahrscheinlich fliegen auch von ihren Tagesplätzen auf und balzenden entgegen.

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Observations on the display flight of the woodcock(Scolopax rusticola)

Summary During continuous observations of a woodcock breeding territory in Lower Saxony in 1974, the course of events of the display season and the role of display flights in relation to breeding was studied. In 1972 und 1973 display flights were studied in various other parts of Lower Saxony. The first woodcocks were observed in 1973 and 1974 during the second five-day period of March; migration was observed in 1974 through the end of April.At the end of migration the males continued their display flights without interruption. The highest intensity of display flights was recorded in the morning and in the evening in June.Display flights began in the morning always at the same light intensity. At night, from May on, the first woodcocks displayed before sunset and at much higher light intensities than in March and April. The cessation of display during the day and at night was well correlated with photoperiod. The display is characterized by a conspicuous time pattern. During pauses in the display flights the males landed for feeding. The normal vocalization of the males consisted of a regularly repeated display note of three elements with frequent variations (Tab. 1).The main purpose of the display flights is to find females ready to mate. Previously, it was supposed that finding of mates depended exclusively on acoustic communication.I was able to observe that the males also attempt to find females visually. Most likely, females fly up from their diurnal roosts and approach displaying males.

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Die Arbeit wurde vom Deutschen Jagdschutz Verband, Bonn, finanziell unterstützt.     

Effect of fat free diet during the last week of pregnancy upon the linoleic and arachidonic acid content of fetal organ lipids and placenta lipids of the rat

Pregnant Wistar rats were fed a fatfree diet from day 16--22 of pregnancy. On day 22, the fatty acid components of cholesterol esters, triglycerides, free fatty acids and phospholipids of maternal (brain, muscle, serum, white adipose tissue, liver) and fetal (brain, carcass, serum, liver) tissues, including the placenta, were examined gaschromatographically for the participation of linoleic and arachidonic acid. In all fetal and maternal organs the linoleic acid levels in the fatty acid patterns were strongly reduced. The alterations nearly always involved all the lipid fractions of a tissue and were mostly equal within a tissue. The strongest decreases of linoleic acid occurred in the placenta, and the weakest, in the lipids of maternal muscle and maternal adipose tissue. The linoleic acid alterations were principally similar in fetal and the corresponding maternal tissues, while being less pronounced in case of maternal muscle. The participation of arachidonic acid in the fatty acid pattern is completely retained in the lipids of fetal organs, and is even enhanced in those of the placenta.     

Kidney grafting between rats which carry recombinant major histocompatibility haplotypes

Kidney transplantation was performed between three congenic rat strains which carried the major histocompatibility haplotypesRT1 ^a ,RT1 ^u orRT1 ^ar1 , the latter being a recombinant betweenRT1 ^a andRT1 ^u . This combination made it possible to test separately the effects of incompatibility for RT1. A-region products (classical transplantation antigens, histocompatibility antigens) and for RT1.B-region products (Ia-antigens, strong mixed lymphocyte stimulating antigens, histocompatibility antigens) as well as RT1.C-region products (lymphocyte differentiation antigens, histocompatibility antigens). It is shown that A plus B plus C, as well as A or B plus C-region incompatibility led to kidney-graft rejection and that matching for either classical transplantation antigens or Ia and strong mixed lymphocyte stimulating antigens had no clear differential prognostic effect on kidney-graft survival.     

Genetic definition of a further gene region and identification of at least three different histocompatibility genes in the rat major histocompatibility system

Two new recombinant haplotypes of the rat major histocompatibility system,RT1, have been detected in [LEW.1A (RT1 ^a ) ×LEW.1W (RT1 ^u )] × LEW 1N(RT1 ⁿ ) segregating hybrids. Recombinantr3 carries theRTL1. A region (determining classical transplantation antigens) and theRT1.B region (determining strong mixed lymphocyte reactivity and genetic control of antipolypeptide immune responsiveness) of the RT1^a parent, bur rejects RT1^a skin grafts. Recombinantr4 carries theA andB regions of the RT1^u parent, but rejects RT1^u skin grafts. The two histocompatibility genes detected are allelic to each other. The relevant locus, designated asH-C, maps to theB-region side of theRT1 system and appears to mark a thirdRT1 gene region,RT1.C. Availability of haplotypes r3 andr4 allowed the definition of a histocompatibility locus in theB region,H-B. The products ofH-C, H-B and of the previously describedH-A gene vary in antigenic strength.     

Volume flows across gallbladder epithelium induced by small hydrostatic and osmotic gradients

Summary The hydraulic conductivity of rabbit gallbladder epithelium has been studied using a continuous volumetric method based on capacitance measurements. The time resolution for measuring osmotic flows is in the range of seconds. Volume flows have been induced by osmotic gradients between 0 and 100 mosmol. In this range the flow-force relation is linear and theP _f value is 9.3×10^–3 cm/sec. After correction for solute polarization effects, theP _f value amounts to 0.05 cm/sec. The observed flow is constant between 5 sec up to 20 min after a sudden increase in the osmolarity of the mucosal solution. The wet weight of the gallbladder tissue decreases by 22% and increases by 30% during osmotic flows from serosa to mucosa and from mucosa to serosa, respectively. Volume flows induced by hydrostatic pressure gradients on the mucosal surface are linearly related to the driving forces between 0 and 40 mbar. TheP _f value is 0.15 cm/sec. The volume flows are constant between 2 sec and 15 min after pressure application. The flow-force relation for pressure gradients on the serosal surface is markedly nonlinear for gradients greater than 5 mbar. Below 5 mbar theP _f value is 4.5 cm/sec. From electrical measurements, e.g., resistance and streaming potentials, and from flux studies with inulin and polyethylene glycol 4000, it is concluded that hydrostatic and osmotic gradients are not comparable when they are applied to gallbladder epithelium. They induce volume flows across different pathways, e.g., osmosis predominantly across the cellular route and pressure filtration predominantly across paracellular routes.     

Circadian placebo and ACTH effects on urinary cortisol in arthritics

The effect of placebo and ACTH-1-17 (Synchrodyn®, Hoechst) upon urinary free cortisol was examined at 5 different circadian stages on 10 men with Steinbrocker Stage II–III rheumatoid arthritis. A mean cosinor analysis of urinary cortisol data from the subjects prior to treatment with either ACTH or placebo revealed a statistically highly-significant rhythm. A circadian variation in a response of urinary free cortisol to a placebo was also seen. Moreover, the response of the midline-estimating statistic of rhythm (rhythm-adjusted circadian average) of urinary free cortisol to ACTH-1-17 by patients with rheumatoid arthritis is circadian rhythmic. This reactivity rhythm is out of phase with the spontaneous rhythm in urinary cortisol acrophases—in the tests limited thus far to midsummer. The further assessment of the circadian component in the context of broader interactions by rhythms with other frequencies in various conditions in health and disease is warranted by the demonstration of rhythms here presented for men with rheumatoid arthritis.     

Progesterone in the uterus. VIII. Uptake of corticosterone and incorporation of progesterone under concurrent injection of corticosterone into rat uterus

A study of the subcellular distribution of radioactivity in rat uterus after injection of labelled corticosterone showed that the radioactivity was observed in all fractions from 5 min. to 120 min. A maximum uptake was observed 10 min. after application of the labelled steroid. Competitive uptake of radioactive progesterone and unlabelled corticosterone was assayed 10 min. after injection of the hormone mixture. The ratio between radioactive progesterone and unlabelled corticosterone was 1 : 1 and 1 : 2 (moles:moles), respectively. Compared with control experiments with rats which had received radioactive progesterone alone, the results gave evidence that progesterone found in all subcellular fractions and in the total homogenate was not depressed by unlabelled corticosterone. However, unlabelled progesterone reduced the tritiated progesterone in uterine tissue. This observation demonstrates that the uptake of progesterone by rat uterus is specific.