Exploring the factors determining the dynamics of different protein folds.

Normal mode analyses of homologous proteins at the family and superfamily level show that slow dynamics are similar and are preserved through evolution. This study investigates how the slow dynamics of proteins is affected by variation in the protein architecture and fold. For this purpose, we have used computer-generated protein models based on idealized protein structures with varying folds. These are shown to be protein-like in their behavior, and they are used to investigate the influence of architecture and fold on the slow dynamics. We compared the dynamics of models having different folds but similar architecture and found the architecture to be the dominant factor for the slow dynamics.

Orexins and their receptors: structural aspects and role in peripheral tissues.

Orexins, also named hypocretins, were discovered in 1998 by subtractive cDNA cloning or orphan receptor technologies. Prepro-orexin is enzymatically matured into two peptides, orexin-A and orexin-B which are 33- and 28-amino-acid peptides, respectively. Two cloned orexin receptors OX1R and OX2R are serpentine G-protein-coupled receptors, both of which bind orexins and are coupled to Ca2+ mobilization. Orexins are neuropeptides present in hypothalamic neurons that project throughout the central nervous system to nuclei involved in the control of feeding, sleep-wakefulness, neuroendocrine homeostasis and autonomic regulation. The interest of investigators in orexins has focused on narcolepsy, since genetic or experimental alterations of the orexin system are associated with this sleep disorder. However, orexins are not restricted to the hypothalamus and together with their receptors they are expressed in peripheral tissues. This new multifaceted aspect of orexin biology is reviewed here in descriptions of (i) the proform, maturation and structure of orexins, (ii) the structure, signal transduction and pharmacology of orexin receptors and (iii) the expression of orexins and orexin receptors as well as their biological role in the hypothalamus-pituitary-adrenal axis, gastrointestinal tract, endocrine pancreas and other peripheral tissues.

The search for a new model structure of beta-factor XIIa.

We present the search for a new model of beta-factor XIIa, a blood coagulation enzyme, with an unknown experimental 3D-structure. We decided to build not one but three different models using different homologous proteins as well as different techniques and different modelers. Additional studies, including extensive molecular dynamics simulations on the solvated state, allowed us to draw several conclusions concerning homology modelling, in general, and beta-factor XIIa, in particular.

Protein kinase C regulates nutrient uptake and growth in hepatoma cells.

BACKGROUND: Human hepatoma cells extract glutamine at rates severalfold greater than normal hepatocytes through a high-affinity transporter encoded by the ATB0 gene, which contains two putative phosphorylation sites for protein kinase C (PKC). The studies presented here were undertaken to determine whether System B0-mediated glutamine uptake regulates hepatoma growth and whether PKC regulates the activity of this transporter. METHODS: SK-Hep cells were treated with the PKC activator phorbol 12-myristate 13-acetate (PMA) and the initial-rate transport of glutamine and other nutrients measured at specific times thereafter. Growth rates were monitored during culture +/- PMA or an excess of system B0 substrates relative to glutamine. RESULTS: PMA treatment exerted a rapid (half-life approximately 15 minutes) concentration-dependent inhibition of glutamine uptake rates to 50% of control values via a posttranslational mechanism that decreased transporter maximum velocity. This effect persisted after 24 hours and was abrogated by the PKC inhibitor staurosporine. PMA also significantly decreased amino acid transport System y+ and System L activities but no System A. Chronic treatment with PMA (PKC depletion) inhibited SK-Hep growth, as did attenuation of System B0-mediated glutamine uptake with other B0 substrates. CONCLUSIONS: System B0-mediated glutamine uptake regulates hepatoma cell growth, whereas PKC influences both processes.

Transdermal fentanyl in the management of cancer pain in ambulatory patients: an open-label pilot study.

We performed an open-label pilot study to define analgesic efficacy, acceptability, and toxicity of transdermal fentanyl in an ambulatory population of patients with cancer pain. Our 7-day study included 35 patients, all of whom had failed a trial of an opioid analgesic conventionally used for moderate pain. Patients received either a 25 micrograms/hr or 50 micrograms/hr fentanyl transdermal patch depending on prior opioid dose. Pain was measured daily utilizing visual analogue (VAS) and categorical (CAT) scales. Hours of nighttime sleep, quality of life, toxicities, and use of rescue medication were also assessed. There was a 24%-29% reduction in mean VAS and CAT pain scores as compared with the baseline and a 25% increase in mean hours of nighttime sleep. Fifty-nine percent of those patients responding (46% of all study patients) were satisfied to very satisfied with the analgesia provided by transdermal fentanyl. Six percent of all study patients were not at all satisfied with the pain relief obtained. Toxicities were similar to those seen with other opioids. No patient developed severe sedation or respiratory depression. The 25-50 micrograms/hr patch appears to be a safe starting dosage in ambulatory patients previously receiving opioids conventionally used for moderate pain.

A pilot evaluation of alternating preoperative chemotherapy in the management of patients with locoregionally advanced breast carcinoma.

BACKGROUND: This prospective trial was conducted to evaluate the outcome of patients treated with preoperative and post operative chemotherapy, mastectomy, and irradiation for locoregionally advanced breast carcinoma. METHODS: Between June 1986 and September 1990, 71 patients received 2 cycles of doxorubicin that alternated with 2 cycles of cyclophosphamide, methotrexate, and 5-fluorouracil prior to mastectomy; irradiation was administered when the tumor was not amenable to surgical resection. Additional chemotherapy and tamoxifen, in hormone receptor-positive tumors, was used after mastectomy. Post-operative irradiation was given on a selective basis for patients at high risk for locoregional disease recurrence. RESULTS: Although 5 patients (7%) had disease progression, clinical partial or complete tumor response to preoperative chemotherapy was noted in 46 patients (65%). Sixty-eight patients (96%) underwent mastectomy. With a median follow-up of 52 months, the relapse-free and overall survival rates at 5 years were 42% and 57% respectively. Locoregional tumor recurrence occurred in 14 patients (20%), and 28 patients (39%) developed metastatic disease. Menopausal status, clinical presentation (noninflammatory vs. inflammatory), and American Joint Committee on Cancer clinical stage were independent covariates associated with patient outcome. CONCLUSIONS: Preoperative alternating chemotherapy, with the selective use of irradiation, resulted in significant locoregional disease regression and the successful integration of mastectomy into the therapeutic strategy. Locoregional tumor control and relapse-free and overall survival estimates for the approach described herein compared favorably with other comtemporary reports for this condition.

[Splenic infarction caused by paradoxical emboli in severe pulmonary hypertension]. / Milzinfarkte durch paradoxe Embolie bei schwerer pulmonaler Hypertonie.

HISTORY AND CLINICAL FINDINGS: A 55-year-old woman developed increasing shortness of breath and breath-independent pain in the left lower chest. 20 years previously she had had an episode of pulmonary embolism and 10 years previously a central venous thrombosis in the left eye. No cause of the increased thrombogenesis had been found. On admission she had resting dyspnoea but a stable circulation. On auscultation the breath sounds were diminished over the left base and there was a diastolic murmur over the pulmonary area with an accentuated second sound. There was also marked tenderness below the left costal margin. Recurrent pulmonary embolism or left-sided pleuropneumonia was suspected. INVESTIGATION: Arterial blood gases (without additional oxygen) showed severe hypoxaemia (pO2 42.3 mm Hg, pCO2 27.8 mm Hg, pH 7.455, oxygen saturation 80.5%). Transthoracic and transoesophageal echocardiography showed normal left ventricular dimensions, right atrial and ventricular dilatation, and an atrial septal aneurysm with a right to left interatrial shunt. Right heart catheterisation demonstrated severe pulmonary hypertension. Sonography, computed tomography and scintigraphy revealed multiple splenic infarcts. TREATMENT AND COURSE: Heparinisation was instituted (partial thromboplastin time 70-90 s) and overlapping oral anticoagulation to a Quick value of 20%. Subsequently the calcium antagonist felodipine (15 mg daily) was given. The mean pulmonary artery pressure was 61 mm Hg before and 57 mm Hg after treatment. CONCLUSION: Splenic infarction resulting from paradoxical embolisation is rare, but should be routinely considered in the presence of thromboembolic phenomena.

Pentoxifylline for treatment of cancer anorexia and cachexia? A randomized, double-blind, placebo-controlled trial.

PURPOSE: Based on evidence that suggests pentoxifylline can inhibit tumor necrosis factor, we set out to evaluate the activity and toxicity of this drug in patients with cancer-associated anorexia and/or cachexia. PATIENTS AND METHODS: Seventy patients with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 with cancer anorexia and/or cachexia (defined by a weight loss of > or = 5 lb in the preceding 2 months or a caloric intake < 20 kcal/kg/d) were stratified and then randomly assigned to receive pentoxifylline or identical-appearing placebo tablets in a double-blind fashion. Patients' weights were monitored and patient questionnaires were used to assess appetite, toxicity, and perception of benefit. RESULTS: Pentoxifylline failed to improve the appetites of study patients. Pentoxifylline did not appear to cause any toxicity. CONCLUSION: This study failed to demonstrate any benefit of pentoxifylline at this dose and schedule as therapy for cancer anorexia and/or cachexia.

[Early detection of hepatobiliary involvement in children with mucoviscidosis using duplex sonography of the portal system]. / Frühnachweis einer hepatobiliären Beteiligung bei Kindern mit Mukoviszidose mit Hilfe der Duplexsonographie des Portalsystems.

To investigate early signs of hepatobiliary disease in CF, we measured portal, splenic, superior mesenteric vein and hepatic artery diameters, maximal flow velocity (Vmax) and time average velocity (TAV) in 25 males and 17 females with CF. Hepatic artery resistance, regional blood flow and liver perfusion were calculated. According to liver enzyme data (aminotransferases raised greater than 30 U/l) and sonographic findings (nodular changes), there were 17 CF-patients (mean age 11.4 yrs; range 0.75-31) with and 25 CF-patients (mean age 7.8 yrs; range 0.25-32) without liver involvement (L+/L-). No patient had clinical signs of portal hypertension. 61 healthy children were studied for control. Diameter of portal vein (PVD) and flow data for portal vein showed consistent abnormalities (mean +/- SD): CF-L+ CF-L- Control PVC (mm/m2) 10.7 +/- 3.9*** 10.5 +/- 3.4*** 7.2 +/- 1.3 Vmax (m/sec) 0.23 +/- 0.06*** 0.30 +/- 0.06*** 0.40 +/- 0.14 TAV (m/sec) 0.12 +/- 0.04*** 0.16 +/- 0.04* 0.18 +/- 0.05 Differences were statistically significant (* p less than 0.05, *** p less than 0.001) for CF-patients versus controls. Data for splenic and mesenteric veins and for hepatic artery were moderately alterated, with a significant reduction in TAV and Vmax of splenic vein for CF-L+ versus controls. Liver perfusion and portal vein flow showed no relevant differences in CF-patients versus controls. It is concluded that portal system abnormalities, especially a decrease in Vmax and TAV of portal vein shown by duplex sonography, may be earlier indicators of CF liver disease than biochemical and clinical signs.

Evaluation of the continuous infusion of etoposide plus cisplatin in metastatic breast cancer. A collaborative North Central Cancer Treatment Group/Mayo Clinic phase II study.

A prospective clinical trial was done to evaluate the efficacy and toxicity of cisplatin plus etoposide (VP-16) in patients with breast cancer who failed one previous chemotherapy regimen for advanced disease or relapsed within 12 months of adjuvant chemotherapy. Partial responses occurred in 11 of 44 evaluable patients (25%; 95% confidence interval (CI), 13% to 40%). The median time to disease progression in responding patients was 4 months (range, 3 to 6+ months), whereas the median time to disease progression and survival for all patients who were treated were 3 and 7 months, respectively. There was marked toxicity related to this protocol treatment including pancytopenia, gastrointestinal upset, and renal insufficiency. Two treatment-related deaths occurred; one from sepsis and one from renal failure. Thus, this regimen, as second-line chemotherapy for women with metastatic breast cancer, resulted in moderate, short-term, antitumor activity at the expense of marked toxicity.

Randomized clinical trial of doxorubicin alone or combined with mitolactol in women with advanced breast cancer and prior chemotherapy exposure.

One hundred fifty-one women with advanced breast cancer who had failed prior chemotherapy were randomized to monthly courses of doxorubicin (60 mg/m2 I.V. day 1, observation after 500 mg/m2) or doxorubicin (40 mg/m2 I.V. day 1; maximum 500 mg/m2) and mitolactol (135 mg/m2 orally, days 1-10; 180 mg/m2 after maximum doxorubicin). Median survival times were 232 days for doxorubicin and 225 days for doxorubicin + mitolactol, and median times to progression were 112 days and 97 days, respectively. Results are inconsistent with a 25% improvement in survival or time to progression for doxorubicin + mitolactol (p = 0.04 and 0.02, respectively, adjusted for stratification factors but not multiple testing). Regression rates for all patients, both measurable and evaluable, were 30% for doxorubicin alone and 26% for doxorubicin + mitolactol. Regression rates were significantly higher in patients with measurable indicator lesions. Cardiac toxicity was seen in four patients, all of whom were receiving doxorubicin alone. It appears that the combination of doxorubicin + mitolactol is not substantially more effective than doxorubicin alone in women with advanced breast cancer and prior chemotherapy exposure.

[Local anesthesia after percutaneous application. II]. / Lokalansthesie nach percutaner Aufnahme. II. Mitteilung

Cyclohexane and hexadecane have been found to accelerate the penetration of local anesthetics (lidocaine, fomocaine, procaine) through the intact skin of guinea-pigs. Dissolved in cyclohexane, the potency of lidocaine is twice that of fomocaine, the latter being more active than procaine. When dissolved in hexadecane, the activity of the local anesthetics in markedly reduced. In combination with 2-butanone, (30% w/w), a solvent without any apparent effect on the permeability of skin, enhanced anesthetic effects are noted. The anesthetic bases, dissolved in dimethyl sulfoxide, produce a much deeper and longer local anesthetic effect than the solutions of their salts.

[Heart and circulatory effects of quinidine stereoisomers]. / Herz--Kreislaufwirkungen von Chinidinstereoisomeren

Quinidine sulfate shows dose-related activity. On the cardio-vascular system of anaesthetized cats. It reduces heart rate, prolongs QRS and QT of the ECG, lowers peripheral blood pressure and depresses slightly myocardial contractility. Quinidine hydrochloride lowers blood pressure but alters the ECG only in very high doses. Epiquinidine has no blood pressure lowering activity. According to the Easson and Stedman hypothesis this may be the result of stereoselectivity of alpha-adrenergic receptors. Only very high doses of the epimer produce a transient decrease of blood pressure. The ECG-waves are, however, markedly altered. QT is prolonged only with epiquinine-epiquinidine-sulfate. The salts of epiquinidine tested are much better water-soluble than those of quinidine.

[Effects of pentaformylgitoxin (gitoformate) on the cardiovascular system of anesthetized cats]. / Wirkungen von Pentaformylgitoxin (Gitoformat) auf das Herz-Kreislaufsystem narkotisierter Katzen

In small and medium doses 3 beta, 14 beta-dihydroxy-16 beta-formyloxy-5 beta-card-20-[22]-enolide-3-tetraformyltridigitoxoside (pentaformylgitoxin; gitoformate) shows a greater positive inotropic and blood pressure increasing potency than do digitoxin and beta-acetyldigoxin. In high doses this influence on contractility is exceeded by digitoxin, that on blood pressure is equalled. None of the substances tested changes heart rate. Arrhythmias with gitoformate are only seen in lethal doses, with digitoxin and beta-acetyldigoxin two dose levels earlier.

[Action of fomocaine on heart and circulation (author's transl)]. / Herz-Kreislaufwirkungen des Fomocains

Fomocaine shows antiarrhythmic properties. It prolongs the periods of the ECG (anaesthetized cats) and the functional refractory period (left atria of guinea-pigs, electrically driven). Effects on these parameters are qualitatively the same as with quinidine. Quantitatively fomocaine prolongs the functional refractory period in the same, the PQ-interval to a greater extent than does quinidine. In contrast quinidine has a greater effect on QRS- and QT-interval. Up to higher doses fomocaine's efficacy on contractility (dp/dtmax) and blood pressure is opposite to quinidine because they are increased by fomocaine and decreased by quinidine. The lack of toxic ECG-signs prior to lethal dosis makes fomocaine dangerous in overdosage.