Changes in the activity of alcohol dehydrogenase isoenzymes during the estrus cycle in the vagina of the rat

In rodents, the vaginal epithelium undergoes cyclical changes with an alternating pattern of keratinization and mucification. It has been known for decades that vitamin A and its active form retinoic acid are responsible for normal epithelial homeostasis. However, it has not so far been certain which enzymes catalyze the first and rate-limiting step in retinoic acid synthesis. By means of microdissection and ultrathin-layer gel electrophoresis, alcohol dehydrogenase isoenzyme activity was determined quantitatively in the various layers of the vaginal mucous membrane. It was found that, in the rat, only alcohol dehydrogenase 3 and 4 are expressed. Marked cyclical changes of alcohol dehydrogenase 4 activity in the stratum germinativum of the vaginal epithelium strongly support the assumption that this isoenzyme is responsible for retinoic acid synthesis, and that it is essential for the changes accompanying keratinization and mucification.     

Erinnerungen an Ornithologen, die ich kannte (2. Teil)

Zusammenfassung Der Aufsatz stellt eine Fortsetzung der Niederschrift eines Vortrages des Autors dar, die im Heft 3/1998 des Journals veröffentlicht wurde. Die hier wiedergegebenen Informationen wurden am 23. September 1999 vor der 132. Jahresversammlung der DO-G in Bayreuth vorgetragen. Erneut berichtete der Autor aus Biographien mehrerer ornithologisch interessierter Naturkundler und schenkt der Untersuchung des Einflusses politisch-gesell-schaftlicher Verhältnisse auf deren wissenschaftliche Tätigkeit und persönliche Schicksale besonderes Interesse. Auch wirkliche und potentielle Nobelpreisträger sind unter den geschilderten Persönlichkeiten. Der Autor geht auch zurück in die Geschichte des vorigen Jahrhunderts, um zu belegen, dass die Verhältnisse in den Diktaturen der jüngeren Zeit kein Einzelphänomen waren. Auch diesmal basiert die Schilderung auf persönlichen Erfahrungen, die oft durch Informationen aus Archiven, diversen Publikationen und Berichten noch lebender Zeitzeugen überprüft und ergänzt wurden.

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Reflections on ornithologists I have known (part 2)

Summary The content of this paper was presented at the 1999 Annual General Meeting of the German Ornithologists Society held in Bayreuth as a sequel of the presentation given in 1997, which has been published (J. Ornithol. 139: 325–348, 1998). Basing his work on some further 15 personal histories of naturalists, the author is again investigating the impact of socio-political relationships on their scientific activities and the involvement ofsome of the scientists in politics. In addition to famous personalities from the middle of the 20th century, such as the Nobel Prize winner Konrad Lorenz, analyses were also made in respect of some nineteenth century personalities and some from the last decade of the twentieth. The author is of the opinion that a knowledge of history is important not only for future development in general, but also for science, i. a. for ornithology.

     

Different signaling pathways are involved in CCK(B) receptor-mediated MAP kinase activation in COS-7 cells

Recently, the involvement of the MAP kinase ERK in mitogenic signaling of cholecystokininB (CCK(B)) receptors has been shown. However, the intracellular effector systems involved in this signaling pathway are poorly defined. In this study, we used COS-7 cells transiently transfected with the human CCK(B) receptor to investigate cholecystokinin-induced MAP kinase activation. CCK-8 induced activation of ERK2 which is associated with its phosphorylation and localization in the nucleus. The CCK-8-dependent ERK stimulation is sensitive to wortmannin an inhibitor of phosphoinositide 3-kinases (PI3Ks) indicating the involvement of PI3K activity. To identify the PI3K species involved in mitogenic signaling of the CCK(B) receptor several dominant-negative mutants of PI3K regulatory and catalytic subunits were transiently expressed. Surprisingly, different catalytically inactive mutants of the G protein-sensitive PI3Kgamma did not affect ERK stimulation induced by CCK, whereas a dominant-negative mutant of the regulatory p85 subunit induced significant inhibition of CCK-dependent ERK activity. These results indicate an involvement of PI3K class 1A species alpha, beta or/and delta in signal transduction via CCK(B) receptors. In addition, protein kinase C (PKC)-dependent signaling pathways contribute to CCK(B)-mediated MAP kinase signaling as shown by inhibition of CCK-8-induced ERK activation by the PKC inhibitor bisindolylmaleimide.     

Comparison of ReoPro((R)) (abciximab) versus intracoronary thrombolysis for early coronary stent thrombosis

AIMS: This study evaluated the treatment of early coronary stent thrombosis with intracoronary urokinase or the platelet glycoprotein IIb/IIIa receptor inhibitor ReoPro (abciximab). METHODS AND RESULTS: Seventy-four patients (126 stents) were treated immediately after identification of early (0-30 days) coronary stent thrombosis. Twenty-nine patients were treated with intracoronary urokinase (UK) (UK alone in 19; UK and additional balloon angioplasty in 10) and another 45 patients were given ReoPro((R)) (abciximab) (0.25 mg/kg as a bolus alone in 26, abciximab with additional balloon angioplasty in 19) within 30 days of stent implantation. TIMI grade 3 flow was obtained in 23 patients (79%) in the UK group and in 38 (84%) in the abciximab group (nonsignificant). Three patients (10%) in the UK group and one (2%) in the abciximab group underwent repeat percutaneous transluminal coronary angioplasty (PTCA) (nonsignificant). Five patients (17%) in the UK group and three (7%) in the abciximab group were referred for urgent coronary artery bypass graft surgery (CABG) because of residual thrombus and refractory ischemia (nonsignificant). Repeat revascularization was necessary in eight patients (28%) in the UK group versus four (9%) in the abciximab group (p < 0.05). Five patients (17%) in the UK group and eight (18%) in the abciximab group developed myocardial infarction (nonsignificant). Five patients (17%) in the UK group (cardiogenic shock (three), cerebral hemorrhage (one) and pneumonia (one)) and three (6.6%) in the abciximab group (cardiogenic shock (two), heart failure (one)) died within 30 days (nonsignificant). Overall, noncardiac complications (bleeding including surgical repair of groin) were observed in 11 patients (38%) in the UK group and three (7%) in the abciximab group (p < 0.001). CONCLUSION: Compared to urokinase, abciximab reduced the need for repeat revascularization procedures and the risk of noncardiac events, including bleeding complications in patients with early coronary stent thrombosis.     

Efficacy tests and determination of optimal spray timing values to control nantucket pine tip moth (Lepidoptera: Tortricidae) infestations

The Nantucket pine tip moth, Rhyaciona frustrana (Comstock), a common regeneration pest of loblolly pine, Pinus taeda L., has been shown to reduce tree volume yields through larval feeding. Chemical applications can be effective in protecting trees from the growth losses associated with this feeding, and optimum spray timing values are commonly used to reduce the number of necessary applications and to increase insecticide efficacy. Optimal spray timing values for the Georgia Piedmont were obtained for the following four insecticides available for use in loblolly pine plantations: permethrin (Pounce), lambda-cyhalothrin (Warrior T), spinosad (SpinTor 2 SC), and Bacillus thuringiensis variety kurstaki Berliner (Foray 48B). Optimal timing values were similar between the first and second generations for each of these compounds. All of the insecticides used in this study significantly reduced tip moth damage below the control treatment levels. Lambda-cyhalothrin was the most efficacious and had the longest spray timing window. B. thuringiensis was the least effective and had the shortest timing window. Spinosad and permethrin were similar in efficacy and spray timing values. This information is applicable to regions where there are three tip moth generations per year, as found in the southern Piedmont region and the coastal plain of Virginia and most of North Carolina.     

The Doa4 deubiquitinating enzyme is functionally linked to the vacuolar protein-sorting and endocytic pathways

The Saccharomyces cerevisiae DOA4 gene encodes a deubiquitinating enzyme that is required for rapid degradation of ubiquitin-proteasome pathway substrates. Both genetic and biochemical data suggest that Doa4 acts in this pathway by facilitating ubiquitin recycling from ubiquitinated intermediates targeted to the proteasome. Here we describe the isolation of 12 spontaneous extragenic suppressors of the doa4-1 mutation; these involve seven different genes, six of which were cloned. Surprisingly, all of the cloned DID (Doa4-independent degradation) genes encode components of the vacuolar protein-sorting (Vps) pathway. In particular, all are class E Vps factors, which function in the maturation of a late endosome/prevacuolar compartment into multivesicular bodies that then fuse with the vacuole. Four of the six Did proteins are structurally related, suggesting an overlap in function. In wild-type and several vps strains, Doa4-green fluorescent protein displays a cytoplasmic/nuclear distribution. However, in cells lacking the Vps4/Did6 ATPase, a large fraction of Doa4-green fluorescent protein, like several other Vps factors, concentrates at the late endosome-like class E compartment adjacent to the vacuole. These results suggest an unanticipated connection between protein deubiquitination and endomembrane protein trafficking in which Doa4 acts at the late endosome/prevacuolar compartment to recover ubiquitin from ubiquitinated membrane proteins en route to the vacuole.     

Evolution of virulence in a heterogeneous host population

Abstract.— There is a large body of theoretical studies that investigate factors that affect the evolution of virulence, that is parasite-induced host mortality. In these studies the host population is assumed to be genetically homogeneous. However, many parasites have a broad range of host types they infect, and trade-offs between the parasite virulence in different host types may exist. The aim of this paper is to study the effect of host heterogeneity on the evolution of parasite virulence. By analyzing a simple model that describes the replication of different parasite strains in a population of two different host types, we determine the optimal level of virulence in both host types and find the conditions under which strains that specialize in one host type dominate the parasite population. Furthermore, we show that intrahost evolution of the parasite during an infection may lead to stable polymorphisms and could introduce evolutionary branching in the parasite population.     

The effect of superpulsed carbon dioxide laser energy on keloid and normal dermal fibroblast secretion of growth factors: a serum-free study

An in vitro model was used to determine the effect of superpulsed CO2 laser energy on normal dermal and keloid-producing fibroblast proliferation and release of growth factors. Growth factors assayed included basic fibroblast growth factor (bFGF) and transforming growth factor beta1 (TGF-beta1). bFGF is mitogenic, inhibits collagen production, and stabilizes cellular phenotype. TGF-beta1 stimulates growth and collagen secretion and is thought to be integral to keloid formation. Growth in a serum-free medium allowed measurement of these growth factors without confounding variables. Keloid and normal dermal fibroblasts cell lines were established from facial skin samples using standard explant techniques. Samples consisted of three separate keloid and three separate normal dermal fibroblast cell lines. Cells were used at passage 4 to seed 24-well trays at a concentration of 6 x 10(4) cells per milliliter in serum-free medium. At 48 hours, 18.8 percent of each cell well was exposed to a fluence of 2.4, 4.7, and 7.3 J/cm2 using the superpulsed CO2 laser. Cell viability and counts were established at four time points: 0 (time of superpulsed CO2 laser treatment), 24, 72, and 120 hours. Supernatants were collected and assessed for bFGF and TGF-beta1 using a sandwich enzyme immunoassay. All cell lines demonstrated logarithmic growth through 120 hours (conclusion of experiment), with a statistically significant shorter population doubling time for keloid fibroblasts (p < 0.05). Use of the superpulsed CO2 laser shortened population doubling times relative to that of controls; the differences were statistically significant in keloid dermal fibroblasts when fluences of 2.4 and 4.7 J/cm2 were used (p < 0.05 and 0.01, respectively). bFGF was present in greater levels in normal dermal fibroblasts than in keloid dermal fibroblasts. Application of superpulsed CO2 demonstrated a trend toward increased bFGF secretion in both fibroblast types; the increase was significant in the keloid group at 4.7J/cm2. A consistent trend in suppression of TGF-beta1 was seen in both groups exposed to superpulsed CO2, with the maximal effect occurring at 4.7 J/cm2. Serum-free culture sustains logarithmic cell growth and allows growth factor measurement without confounding variables from serum-containing media. Superpulsed CO2 enhances fibroblast replication and seems to stimulate bFGF secretion and to inhibit TGF-beta1 secretion. Given the function of these growth factors, the application of superpulsed CO2 may support normalized wound healing. These findings may explain the beneficial effects of laser resurfacing on a cellular level and support the use of superpulsed CO2 in the management of keloid scar tissue.     

Kinetics of absorbance and anisotropy upon excited state relaxation in the reaction center core complex of a green sulfur bacterium

Properties of the excited states in reaction center core (RCC) complexes of the green sulfur bacterium Prosthecochloris aestuarii were studied by means of femtosecond time-resolved isotropic and anisotropic absorption difference spectroscopy at 275 K. Selective excitation of the different transitions of the complex resulted in the rapid establishment of a thermal equilibrium. At about 1 ps after excitation, the energy was located at the lowest energy transition, BChl a 835. Time constants varying between 0.26 and 0.46 ps were observed for the energy transfer steps leading to this equilibrium. These transfer steps were also reflected in changes in polarization. Our measurements indicate that downhill energy transfer towards excited BChl a 835 occurs via the energetically higher spectral forms BChl a 809 and BChl a 820. Low values of the anisotropy of about 0.07 were found in the ‘two-color’ measurements at 820 and 835 nm upon excitation at 800 nm, whereas the ‘one-color’ kinetics showed much higher anisotropies. Charge separation occurred with a time constant varying between 20 and 30 ps. This revised version was published online in June 2006 with corrections to the Cover Date.