Ligands that activate protein kinase-C differ in their ability to regulate basic fibroblast growth factor and insulin-like growth factor-I messenger ribonucleic acid levels

In this study, rat dermal fibroblasts were used as a model system to examine the ability of ligands that are known to activate protein kinase-C to regulate the levels of the mRNAs encoding basic fibroblast growth factor (bFGF) and insulin-like growth factor-I (IGF-I), two growth factors that are thought to be important in processes such as tissue repair and regeneration and wound healing. Treatment of fibroblasts with the phorbol ester phorbol 12-myristate 13-acetate (PMA), thrombin, bradykinin, serotonin, angiotensin-II, or bombesin increased protein kinase-C activity to a similar degree. Treatment of fibroblasts with 1 microM serotonin transiently increased bFGF mRNA levels about 3-fold compared to the level in control cells maintained in serum-free medium with 0.25% BSA and decreased IGF-I mRNA levels by approximately 50% compared to the level in control cells. This is similar to the previously described changes induced by bradykinin in these cells, but different from the more marked and sustained changes induced by thrombin and PMA. In contrast, angiotensin-II and bombesin had no effect on bFGF or IGF-I mRNA levels. The effects of serotonin, bradykinin, and PMA on bFGF and IGF-I mRNA levels were abrogated by preincubation of cells in 250 nM PMA to down-regulate protein kinase-C. In contrast, the effect of thrombin on bFGF mRNA levels was only partially inhibited by down-regulation of protein kinase-C, while its effect on IGF-I mRNA levels was unaffected. The activation of signaling pathways by the different ligands was further investigated to begin to determine the mechanism for the differences in the effects of thrombin vs. serotonin and bradykinin and in the effects of these three ligands vs. angiotensin-II and bombesin. All of the ligands activated phospholipase-D to a similar degree, suggesting that activation of this enzyme was not responsible for the differential effects of the ligands. In contrast, thrombin, serotonin, and bradykinin had marked effects on the hydrolysis of phosphatidylcholine and phosphatidylinositol, whereas bombesin and angiotensin-II had a small effect on phosphatidylcholine hydrolysis and no effect on phosphatidylinositol hydrolysis.(ABSTRACT TRUNCATED AT 400 WORDS)     

Bryostatin 1 induces ubiquitin COOH-terminal hydrolase in acute lymphoblastic leukemia cells

It has been previously reported that Bryostatin 1 (Bryo1) induces differentiation of the human acute lymphoblastic leukemia (ALL) cell line, Reh, to a monocytoid B-cell stage. In this study we demonstrate that a novel protein, ubiquitin COOH-terminal hydrolase (UCH-L1), is associated with this differentiation. Reh cells were treated with 200 nmol/l of Bryo1 for 72 h and analyzed for changes in morphology, surface immunophenotype, acid phosphatase and terminal deoxynucleotidyl transferase. Protein patterns of the parent and differentiated cells, by two-dimensional polyacrylamide gel electrophoresis (2D PAGE), were studied. Bryo1-treated cells expressed morphologic, phenotypic and enzymatic features of the monocytoid B-cell stage. The UCH-L1 enzyme (MW-pl 34-5.3) was detected by 2 D PAGE in the differentiated, but not in parent cells. The presence of UCH-L1 in the Bryo1-treated cells was further confirmed by immunoblotting of 2 D PAGE using UCH-L1 polyclonal antibody. Ubiquitin expression was studied in parent and Bryo1-treated cells and was compared with 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated cells. Both agents, TPA and Bryo1, increased the level of ubiquitin expression as detected by flow cytometry. Sodium borohydride, an inhibitor of UCH-L1, inhibited the Bryo1-induced differentiating effect on Reh cells. To date, the mechanism by which Bryo1, exerts its B-cell differentiating effect is not fully understood. This study shows that UCH-L1 expression may play a major role in Bryo1-induced differentiation in pre-B-ALL.     

Lung reduction surgery in chronic obstructive lung disease

In the 1960s the promise of the Brantigan lung reduction surgery was shattered when it was shown that the improvement in airway conductance drifted back towards the preoperative value over a period of 12 to 18 months. Since then there has been a marked improvement in our understanding of emphysema, its pathology, and techniques for obtaining images of the lung. In addition, reliable automated cardiopulmonary and physiologic testing, advances in critical care medicine, and new pharmacologic agents have improved patient care. Surgical techniques now allow better control of air leaks and access to anatomic regions not previously accessible. The combination of all of the above makes lung reduction surgery worth re-examining as a palliative procedure for severely symptomatic patients. Clearly, it is not a panacea but can in some cases produce dramatic improvements in symptomatology and quality of life. This article presents the available data describing potential mechanisms of improvement and clinical outcomes following lung reduction surgery. It also outlines areas that need further work, such as patient selection and surgical techniques.     

Scrapie infection of transgenic mice leads to network and intrinsic dysfunction of cortical and hippocampal neurones

The human prion encephalopathy Creutzfeldt-Jakob disease often is manifest as rapidly progressing dementia with myoclonus and synchronous, periodic discharges. To investigate the electrophysiology of prion disease we used intra- and extra-cellular recordings from brain slices from Tg(SHaPrP+/+) 81 mice, which express Syrian hamster prion protein and which are susceptible to hamster-passaged scrapie isolates. Forty days after intracerebral inoculation with scrapie isolate Sc237, we recorded prolonged, epileptiform discharges in cortex and hippocampus. Neurological signs were subtle and histopathology was minimal. Central nervous system (CNS) dysfunction progressed; by 57 days the mice were ataxic, had spongiform histopathology and they died in <63 days. During the terminal phase, intrinsic neuronal properties changed dramatically and action potentials broadened from <4 to 20-100 ms in 30% of cortical cells. We conclude that brain dysfunction in experimental scrapie precedes clinical signs and spongiform histopathology, and is preserved in slices maintained in vitro, making it accessible to electrophysiological analysis.     

The prognostic significance of deletion of the long arm of chromosome 20 in myeloid disorders

OBJECTIVE: The effect of cigarette smoking on gallbladder (GB) emptying and refilling after a fatty meal was examined in 10 healthy volunteers (four women and six men, mean age 27.6 yr). METHODS: On three different days, the subjects underwent in randomized order: a control test without smoking (C), or they smoked two cigarettes during the early (0-20 min; S0-20), or late (20-40 min; S20-40) phase of the meal-induced GB emptying. GB volumes were measured ultrasonographically before the meal and at 10, 20, 30, 40, 60, 90, 120, 150, and 180 min postprandially. Two-way ANOVA was applied for statistical assessment of the results. RESULTS: The fasted GB volumes amounted to 15.7 +/- 1.8 cm3 (C), 15.0 +/- 1.7 cm3 (S0-20), and 18.4 +/- 2.3 cm3 (S20-40), F2;18 = 1.524, NS. Maximum GB emptying was observed until 60 min after the meal, with a nadir of the GB volume amounting to 7.3 +/- 1.3 cm3 (C), 6.6 +/- 1.2 cm3 (S0-20), and 7.1 +/- 1.1 cm3 (S20-40). No significant difference was found between the stimuli tested when absolute GB volumes were considered: F2;180 = 2.725, NS. Analysis of the GB emptying-refilling curves normalized for the fasted GB volume revealed that a significant inhibitory effect was produced by smoking two cigarettes during the late phase of GB emptying on the subsequent GB refilling: F2;162 = 11.066, p < 0.001 for the whole curve, and F2;72 = 7.126, p < 0.005 for the refilling phase. A significant contrast was found next between S20-40 and the control day (p < 0.001 whole curve; p < 0.005 refilling phase only), as well as between S20-40 and S0-20 (p < 0.001 whole curve; p < 0.025 refilling phase only). CONCLUSION: We conclude that smoking two cigarettes does not disturb the fatty meal-induced GB contraction in healthy humans. Subsequent GB refilling is delayed if smoking takes place during the late phase of the postprandial GB contraction.     

Design considerations for high performance avalanche photodiodemultiplication layers

We have studied the effect of the thickness of the multiplication region on the noise performance characteristics of avalanche photodiodes (APD's). Our simulation results are based on a full band Monte Carlo model with anisotropic threshold energies for impact ionization. Simulation results suggest that the well known McIntyre expression for the excess noise factor is not directly applicable for devices with a very thin multiplication region. Since the number of ionization events is drastically reduced when the multiplication layer is very thin, the “ionization coefficient” is not a good physical parameter to characterize the process. Instead “effective quantum yield,” which is a measure of the total electron-hole pair generation in the device, is a more appropriate parameter to consider. We also show that for the device structure considered here, modeling the excess noise factor using a “discrete Bernoulli trial” model as opposed to the conventional “continuum theory” produces closer agreement to experimental measurements. Our results reinforce the understanding that impact ionization is a strong function of carrier energy and the use of simplified field-dependent models to characterize this high energy process fails to accurately model this phenomenon     

Long-term prognosis for women with chronic pelvic pain without laparoscopically demonstrable cause

With the object of assessing the long-term prognosis and the frequencies of recurrence and remission in women chronic low abdominal pain without laparoscopically visible cause, questionnaire were sent in 1985 and 1991 to 55 women who had been submitted to laparoscopy in 1982-1984 for this reason. These women had been told that there was no demonstrable explanation of the pain experienced and were then discharged. 65% and 55% respectively had experienced and unfavourable course with considerable and continued symptoms. Only 22% stated in both investigations that they had experienced a favourable course and that they were, by and large, free from pain. 36% changed from an unfavourable to a favourable course or the reverse. The assessment made by the women was confirmed by a series of subordinate questions and this demonstrated a marked difference between the favourable and unfavourable courses of the condition. It is concluded that laparoscopy with exclusion of significant pathology is not, in itself, satisfactory as treatment of this patient group and that no improvement occurs in the course of time. The condition varies greatly with many recurrences and remissions and, for this reason, uncontrolled reports of the therapeutic effects are of no significance. When compared with the literature, it is suggested that this patient group should be referred early in the course of the condition to a therapist with specialist psychological/sexological insight and/or to a physiotherapist with interest in this patient group.     

Reduction and uptake of methylene blue from rat air spaces

The use of methylene blue (MB) to estimate dilution of epithelial lining fluid, which occurs during bronchoalveolar lavage (BAL), is complicated by loss of this redox dye from the air spaces. The rate of MB uptake from the air spaces of isolated rat lungs and the effects of oxidation and reduction on this process were investigated in this study. Movement of MB from the air spaces to perfusate was compared with the corresponding transport of 125I-labeled albumin, [14C]-dextran, 99mTc-labeled diethylenetriaminepentaacetate, [3H]-sucrose, and 3H2O. By the end of 2 min, MB concentrations in the BAL had fallen by 58 +/- 4% (SE; n = 11) and 3H2O by 78 +/- 2% (n = 13), whereas concentrations of the other indicators decreased by approximately 6%. All but 10% of the 3H2O lost from the air spaces was found in the perfusate, whereas 19% of the lost MB was not recovered in the perfusate, suggesting retention of MB in the pulmonary tissues. Absorption of MB from the air spaces was slowed by 20% when the lungs were left unperfused, and absorption was accelerated threefold by reduction of MB to leukomethylene blue with Na2S2O4. In contrast, MB losses from the air space were slowed by the oxidizing agent K3Fe(CN)6 and by addition of superoxide dismutase or ascorbic oxidase. It is therefore possible that ascorbic acid and O2- entering the air spaces reduce MB to the uncharged leuko form. Lowering the pH of the BAL fluid to 3.5 also slowed MB reabsorption. This suggests that acid aspiration may stimulate release of oxidants into the air spaces.