Biomedical subjects
Publications and source records attributed to D Marx.
Actively sensitized Brown Norway rats and guinea pig are useful species for studying drug effects on symptoms of experimental rhinitis. Even if not all symptoms of human rhinitis can be induced and detected in the same animal species, the predictablity of methods generally used is well acceptable. In the present review, advantages and disadvantages of experimental methods of rhinitis will be discussed.
2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) may be used to predict glucose kinetics when the factor relating differences in transport and phosphorylation between compounds remains constant ("lumped constant"). It is not clear whether hyperemia alters that factor. In anesthetized swine, myocardial FDG uptake was estimated by positron emission tomography, during an intracoronary infusion of either adenosine, ATP, or bradykinin (40 microg x kg(-1) x min(-1), 40 microg x kg(-1) x min(-1), and 2 nmol x kg(-1) x min(-1), respectively; n = 6 for all groups). In controls during normal perfusion (n = 6), FDG uptake was 0.78 +/- 0.32 micromol x g(-1) x min(-1), whereas glucose uptake by Fick was 0.71 +/- 0.25 micromol x g(-1) x min(-1) (r = 0.73; P < 0.05). Adenosine increased blood flow from 1.29 +/- 0.43 to 4.80 +/- 2.19 ml x g(-1) x min(-1) (P < 0.05) and glucose uptake from 1.16 +/- 1.10 to 3.35 +/- 2.12 micromol x g(-1) x min(-1) (P < 0.05), whereas FDG uptake in the hyperemic region was lower than remote regions (0.46 +/- 0.29 and 0.95 +/- 0.55 micromol x g(-1) x min(-1), respectively; P < 0.05). In the ATP and bradykinin groups, blood flow increased four- and twofold, respectively, with no net change in glucose uptake. FDG uptake in the hyperemic region was also significantly lower than remote regions. For all animals, the ratio of blood flow in the hyperemic region relative to remote region was inversely proportional to the ratio of FDG uptake in the same regions (r(2)=0.73; P < 0.001). Because nitric oxide elaboration during hyperemia could potentially alter substrate preference and FDG kinetics, six additional swine were studied during maximal adenosine before and after intracoronary N(G)-monomethyl-L-arginine (1.5 mg/kg). Inhibition of nitric oxide had no effect on either regional myocardial substrate uptake or FDG accumulation. In conclusion, hyperemia decreased regional myocardial FDG uptake relative to normally perfused regions and this effect on the lumped constant was independent of nitric oxide.
There are several approaches for developing new antiallergic/antiasthmatic agents. One of them is the improvement of an existing class of effective drug classes. Due to some undesired effects of intranasal or inhaled corticosteroids, there is a need for better tolerated corticosteroids. Loteprednol etabonate belongs to the so-called class of soft steroids because it is metabolized by a one-step reaction (hydrolysis) without using the cytochrome P450 monooxygenase system. In in vitro investigations using human cells, loteprednol inhibited the release of proinflammatory cytokines (e.g., TNF-alpha, GM-CSF, IL-4, IL-5) according to its relative binding potency to the glucocorticoid receptor. In in vivo animal studies, loteprednol effectively inhibited allergically induced vascular leakage in the nasal cavity of actively sensitized Brown Norway rats and rhinorrhea in actively sensitized domestic pigs following nasal challenge. In several models of allergic asthma, it was clearly demonstrated that loteprednol was able to suppress the allergically induced late phase eosinophilia in mice, rats and guinea pigs. After intrapulmonary administration of loteprednol, only a slight, statistically nonsignificant reduction in thymus weight was observed in a dose range far less than the therapeutically relevant doses. Its therapeutic ratio is clearly superior to those of beclomethasone and budesonide. Loteprednol is a safe steroid with an extremely wide range between therapeutic and side effect inducing doses. Its elimination profile, its pronounced binding to plasma protein and erythrocytes and the low oral bioavailability makes this drug highly suitable for nasal or pulmonary use.
Relationships between motivation and transformational leadership were examined in this study. 56 leaders and 234 followers from a variety of organizations were sampled. Leaders were administered the Motivation Sources Inventory and the Job Choice Decision-making Exercise, while followers reported leaders' behaviors using the Multifactor Leadership Questionnaire (MLQ-rater version). Scores on the Motivation Sources Inventory subscales subsequently correlated with the Multifactor Leadership Questionnaire subscales of inspirational motivation, idealized influence (behavior), and individualized consideration (range, r = .13 to .23). There were no significant correlations among any of the Job Choice Decision-making Exercise subscales with any of the variables measured.
BACKGROUND: bcl-2 and bax genes are known to be involved in the control of apoptotic cell death, an important mechanism of growth regulation that influences the biologic behavior of tumors. The aim of the current study was to investigate the relationship of bcl-2 and bax expression to the rate of spontaneous apoptosis in laryngeal carcinomas, and to assess its relations to clinicopathologic features of tumors. METHODS: Immunohistochemical analyses for bcl-2 and bax were performed on paraffin embedded tissue sections from 134 primary laryngeal squamous cell carcinomas. To visualize apoptotic cells, the nick end labeling method was used. The proliferative activity of tumors was analyzed by determination of mitotic indices. RESULTS: bcl-2 immunoreactivity was positively correlated with tumor grade (P < 0.00001), high T category (P < 0.02), metastatic involvement of cervical lymph nodes (P < 0.003), and supraglottic or subglottic location of primary tumors (P < 0.00005). An inverse relation was found between bcl-2 and bax expression (P < 0.004). The frequency of spontaneous apoptosis was closely associated with mitotic activity (P < 0.0004) but appeared to be unrelated to protein levels of bcl-2 or bax as well as to bcl-2:bax ratios. CONCLUSIONS: The results of this study point to the significance of cell proliferation as a major determinant of the rate of spontaneous apoptosis in laryngeal carcinomas. The bcl-2:bax expression ratio obviously does not affect the incidence of apoptosis, but it may be considered as a marker of disease progression and poor prognosis.
In the search for new anti-arrhythmic substances we discovered the class III activity of aminocarboxamides. These compounds show a prolongation of the effective refractory period. With some of them the prolongation is more pronounced after faster than after slower stimulation of the guinea pig papillary muscle. They should therefore be of interest in the treatment of cardiac arrhythmias after myocardial infarction and atrial fibrillation. The chemical synthesis, the structure-activity relationships of the new derivatives, their efficacy on the action potential duration (APD) and the effective refractory period (ERP) in vitro of isolated guinea pig papillary muscles are described and discussed in this paper. Since AWD 160-275 (13) and AWD 23-111 (14) exerted a pronounced APD90 and ERP prolongation at faster stimulation, they were selected for further electrophysiological characterization in vitro and in vivo. Anti-arrhythmic and pro-arrhythmic effects were determined in several animal models in comparison with dofetilide, sematilide, and sotalol. 13 was found to be effective in preventing programmed electrical stimulation-induced arrhythmias in anaesthetized dogs and may therefore contribute to the therapy of dysrhythmias after myocardial infarction. The pro-arrhythmic effect of 14, investigated in a model of triggered activity in chloralose-anaesthetized rabbits under methoxamine infusion, is low in comparison with other class III anti-arrhythmics.
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The actions of a novel selective inhibitor of type 4 cyclic nucleotide phosphodiesterase (PDE4), D-22888, on human airway smooth muscle tone and human eosinophil respiratory burst in vitro and bronchoalveolar eosinophilia in allergen-challenged sensitized guinea pigs in vivo were assessed. D-22888 was a selective inhibitor of PDE4, exhibiting an IC50 against human neutrophil PDE4 of 0.15 microM, compared to IC 50 values of 4.4 microM and 1.1 microM for human platelet PDE3 and PDE5, respectively. D-22888 relaxed inherent tone in human bronchial rings in a concentration-dependent manner with an IC50 of 5.0 microM (geometric mean, 95% ci 3.0-8.4 microM) and also caused a concentration-dependent inhibition of opsonized zymosan-induced superoxide anion generation by human eosinophils with an IC50 of 3.1 microM (1.0-9.2 microM). Treatment of actively sensitized guinea pigs with single oral doses of D-22888 2 h before or 4 h after challenge reduced bronchoalveolar lavage (BAL) eosinophil numbers, 24 h after aerosol allergen challenge, by 48% and 73% at 10 mg/kg and 30 mg/kg, respectively, 2 h pre-challenge and 68% at 30 mg/kg 4 h post-challenge. Chronic twice-daily oral dosing with D-22888 for three days caused inhibition of 24 h post-challenge BAL eosinophilia, amounting to 88% at 30 mg/kg. These in vivo actions were comparable with those achieved with other selective PDE4 inhibitors and with the corticosteroid, dexamethasone. We conclude that D-22888 exerts actions on airway smooth muscle and eosinophil recruitment and activation that suggest that D-22888 may be a promising new drug for use in the treatment of allergic obstructive airways>> diseases such as bronchial asthma.
Drug resistance is one of the most important clinical problems in the treatment of ovarian cancer. This study was designed to determine whether expression of p53 could be used as a marker for predicting the response to chemotherapy of ovarian cancer. Tissue blocks were obtained from 187 patients with diagnosed untreated ovarian cancer. Paraffin sections from the primaries were immunohistochemically analysed for p53 expression. All patients underwent platinum-based chemotherapy after surgery. We analysed whether the number of chemotherapy cycles was related to survival in women with p53 positive and p53 negative ovarian cancer. 27/187 cases were p53 positive. Expression of p53 was associated with other factors of unfavourable prognosis. Patients with p53 positive tumours had a significantly worse prognosis compared with patients with p53 negative tumours (P = 0.037). There was a statistically significant dose-response effect of platinum-based chemotherapy in patients with p53 negative tumours, which could not be seen in patients with p53 positive tumours (P = 0.01 versus P = 0.553). This could also be observed in patients with residual tumour after surgery (P = 0.0001 versus P = 0.8866). Expression of p53 may be an additional useful marker in predicting response to chemotherapy. Thus, it is possible to identify a subgroup of patients who may benefit from alternative therapy regimens.
This study was designed to determine whether c-erbB-2 overexpression could be used as a marker to identify a subgroup of patients with ovarian cancer more likely than others to benefit from chemotherapy. Paraffin sections from tissue blocks from 208 patients with newly diagnosed untreated ovarian cancer were analyzed for c-erbB-2 overexpression. All patients underwent postoperative platin-based chemotherapy. Patients with c-erbB-2 positive tumors had a significantly worse prognosis as compared to patients with c-erbB-2 negative tumors (p = 0.0003). c-erbB-2 findings were not related to tumor stage or histologic findings. There was clear evidence of a dose-response effect with regard to survival in patients with c-erbB-2 negative tumors, which could not be seen in patients with c-erbB-2 positive tumors (p = 0.0341 vs p = 0.3775). We conclude that there is a significant total dose-response effect of platin-based chemotherapy in ovarian cancer patients without overexpression of c-erbB-2 but not in patients with c-erbB-2 overexpression. Overexpression of c-erbB-2 may be a useful marker to identify patients who are most likely to benefit from high-dose chemotherapy.
OBJECTIVE: To study EGF-R, HER-2/neu (p185), p53, Mib-1 (Ki-67), Bax, Bcl-2, ras expression and ploidy in borderline tumors of the ovary by assessing their frequency, and relationship to histologic type, tumor recurrence and survival. METHODS: Fifty-four patients with borderline tumors were followed 3-140 months (median: 38 months). Paraffin-embedded sections were stained using monoclonal antibodies against EGF-R, HER-2/neu (p185), p53, Mib-1 (Ki-67), Bax, Bcl-2, and ras. The immunohistochemical findings were correlated to histologic subtype, tumor recurrence, and survival. RESULTS: Positivity for EGF-R was found in 24% (13/54), in 22% (12/54) p185 was positive, 9% (5/54) of tumors were p53-positive, Mib-1 (Ki-67)-positivity was demonstrable in 46% (25/54). Expression of Bax, Bcl-2, and ras was found in 37% (20/54), 28% (15/54) and in 7% (4/54) of the cases, respectively. CONCLUSION: The data demonstrate expression of EGF-R, p185/HER-2/neu, p53, Mib-1 (Ki-67), Bax, Bcl-2, and ras in a subgroup of patients with ovarian borderline tumors. Further studies to evaluate their prognostic value are warranted.
UNLABELLED: The aim of this study was to determine whether adenosine receptor blockade before ischemia would enhance the degree of stunning and induce a sustained decrease in glucose uptake after reperfusion. METHODS: Stunning was induced in 14 anesthetized swine by partially occluding the left anterior descending artery (LAD) for 20 min (> 80% flow reduction). Seven animals were pretreated with the nonspecific adenosine receptor blocker 8-phenyltheophylline (8-PT; 5 mg/kg), which decreased reactive hyperemia by an average of 38%. Myocardial glucose uptake was assessed 1 hr following reperfusion with PET and the glucose analog 18F-fluorodeoxyglucose (FDG). RESULTS: Before ischemia, systolic shortening in the LAD region was 15% +/- 6% in the control group and 16% +/- 4% in the 8-PT group and in both groups was reduced to - 1% +/- 2% during ischemia. After reperfusion, systolic shortening was 7% +/- 3% in the control group and 2% +/- 3% in the 8-PT group (p < 0.05). Myocardial oxygen consumption before ischemia was 4.58 +/- 3.03 micromol/min/g in the control group and 4.44 +/- 1.83 micromol/min/g in the 8-PT group (ns) and neither were different after reperfusion. In the postischemic LAD region, myocardial glucose uptake was 0.18 +/- 0.15 micromol/min/g in the control group and was similar to that of the 8-PT group (0.17 +/- 0.08 micromol/min/g; ns). CONCLUSION: The nonspecific adenosine blocker 8-PT enhanced the degree of stunning when given before ischemia but did not induce a sustained effect on myocardial glucose uptake after reperfusion.
The Institute of Pharmacology, Academy of Medical Sciences, jointly with AWD (Germany) has synthesized and tested a novel class III antiarrhythmic coded AWD-160-275, a derivative of dicyclohexylamides of aminocarboxylic acids. The compound was shown to prolong cardiac repolarization, to increase atrial and ventricular refractory periods, to decrease sinus nodal automatism, and to unchange intraventricular conduction. The compound proved to be superior to the reference drugs in the rate and duration of antiarrhythmic and antifibrillatory action. In therapeutical doses it has no antiarrhythmic effect. The specific feature of the agent is that there is no relation of longer effective refractory periods to the frequency of stimulation. This property may be useful in treating tachyarrhythmias.
The relative influence of thermal and quantum fluctuations on the proton transfer properties of the charged water complexes H5O2+ and H3O2- was investigated with the use of ab initio techniques. These small systems can be considered as prototypical representatives of strong and intermediate-strength hydrogen bonds. The shared proton in the strongly hydrogen bonded H5O2+ behaved in an essentially classical manner, whereas in the H3O2- low-barrier hydrogen bond, quantum zero-point motion played a crucial role even at room temperature. This behavior can be traced back to a small difference in the oxygen-oxygen separation and hence to the strength of the hydrogen bond.
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Chronic myocardial ischemia and 2-[18F]fluoro-2-deoxy-D-glucose (FDG) uptake were studied with positron emission tomography in 12 swine instrumented with an external constrictor on the left anterior descending coronary artery (LAD). Serial changes in function (by echocardiography), blood flow (with H215O) and FDG were determined weekly. At 1 wk, function was normal and FDG uptake in the LAD and non-LAD regions was 0.43 +/- 0.12 and 0.45 +/- 0.11 mumol. min-1.g-1, respectively (not significant). At approximately 5 wk, LAD wall thickening decreased to 18 +/- 5 from 27 +/- 8% (P < 0.05), whereas LAD and non-LAD blood flows were 0.68 +/- 0.28 and 1.03 +/- 0.25 ml.min-1.g-1, respectively (P < 0.05). At that time, FDG uptake in LAD and non-LAD regions was 0.60 +/- 0.43 and 0.49 +/- 0.30 mumol.min-1.g-1, respectively (P < 0.05). By the use of transmural biopsies (n = 6), ATP and creatine phosphate in the LAD region were 3.62 +/- 0.73 and 5.91 +/- 1.44 mumol/g wet wt, respectively, and neither differed from values in remote regions. In this model of chronic ischemia, hypoperfused dysfunctional regions were characterized by enhanced glucose uptake and preserved bioenergetics. This supports the concept that the myocardium adapts to chronic ischemia.
The c-erbB-2-encoded oncoprotein p185 (HER2) is overexpressed in the fetal epithelium, the placenta and several carcinomas. Elevated serum levels of the released ectodomain (p105) were found in cancer patients and pregnant women at term. In cultured breast cancer cells estradiol inhibited p185 expression and induced growth arrest. These results prompted us to investigate the in vivo influence of serum estradiol and estriol on c-erbB-2 protein levels in pregnancy. We examined chorionic villous tissue extracts and maternal sera obtained from six legal abortions in the first trimester and 20 vaginal deliveries at term. For quantification of c-erbB-2 protein we employed an ELISA. In the first trimester maternal p105 serum levels were significantly (p < 0.0001) lower and p185 tissue levels significantly (p < 0.05) higher than in the third trimester. The highest p105 values were found in additionally examined cord blood. Interindividual regression analyses yielded inverse correlation between estradiol concentrations and placental p185 expression in the first (r = -0.58) and third trimester (r = -0.38) as well as p105 serum levels in the first trimester (r = -0.83). Estriol was correlated positively with p105 values in maternal and umbilical serum but not with placental p185 expression. We conclude that estradiol down-regulates p185 expression in pregnancy whereas the level of maternal p105 depends on the total amount of fetoplacental p185.