Clinical experience transferring kidney transplant patients from Sandimmun to Sandimmun Neoral--results after 3 months

The new galenic formulation of cyclosporine prepared as microemulsion (Sandimmun Neoral, SN) shows a significantly improved correlation between both trough level (Cmin) and dose. Moreover, since the bioavailability is increased by 20 to 30% on average, it may lead to a drug overexposure in so far malabsorbing patients. In order to assess safety and to establish an appropriate procedure to switch patients safely from conventional Sandimmun to SN, we initialized an open, stratified (transplant age) clinical trial enrolling 302 patients of our outpatient clinic. We used a simple 1:1 conversion of the patient's total daily dose. Trough drug levels, as well as serum creatinine, liver enzymes, uric acid, and blood pressure values were measured at baseline, at days 4, 8, 15, 29, and at month 3 after drug substitution. Within the three month observation period, the cyclosporine dose was reduced by 14.2% (204 +/- 60 mg/day baseline vs. 175 +/- 54 mg/day after conversion, p < 0.05). By day 8, the 1:1 dosage conversion resulted in a modest mean increase in drug trough levels (114 ng/ml baseline vs. 120 ng/ml, p < 0.05). This increase was accompanied by a slight increase in mean serum creatinine concentration, a decrease in calculated creatinine clearance, and an increase in mean uric acid values (p < 0.05). Liver enzymes remained unchanged while systolic and mean arterial blood pressure decreased (p < 0.05). Parallel to dosage reduction, drug trough levels had decreased after 1 month to baseline (112 ng/ml) and remained there for the remainder of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell type-specific MxA-mediated inhibition of measles virus transcription in human brain cells

Measles virus (MV)-specific transcription in human brain cells is characterized by particularly low abundances of the distal mRNAs encoding the MV envelope proteins. Similar transcriptional restrictions of the closely related vesicular stomatitis virus have been observed in mouse fibroblasts constitutively expressing the interferon-inducible MxA protein (P. Staeheli and J. Pavlovic, J. Virol. 65:4498-4501, 1991). We found that MV infection of human brain cells is accompanied by rapid induction and high-level expression of endogenous MxA proteins. After stable transfection of MxA, human glioblastoma cells (U-87-MxA) released 50- to 100-fold less infectious virus and expression of viral proteins was highly restricted. The overall MV-specific transcription levels were reduced by up to 90%, accompanied by low relative frequencies of the distal MV-specific mRNAs. These restrictions were linked to an inhibition of viral RNA synthesis and not to a decreased stability of the viral RNAs. Our results indicate that expression of MxA is associated with transcriptional attenuation of MV in brain cells, thus probably contributing to the establishment of persistent MV central nervous system infections. In addition, the mechanism of MxA-dependent resistance against MV infection, in contrast to that of vesicular stomatitis virus, is cell type specific, because an inhibition of MV glycoprotein synthesis independent of transcriptional alterations was observed in MxA-transfected human monocytes (J. J. Schnorr, S. Schneider-Schaulies, A. Simon-Jödicke, J. Pavlovic, M. A. Horisberger, and V. ter Meulen, J. Virol. 67: 4760-4768, 1993).

A 17-kDa Nicotiana tabacum cell-wall peptide acts as an in-vitro inhibitor of the cell-wall isoform of acid invertase

When cell-wall invertase (CWI) from Nicotiana tabacum L. cell-suspension cultures, either non-transformed or transformed with Agrobacterium tumefaciens, was salt-eluted from intact cells and purified on Sulfopropyl-Sephadex (SPS) by pH-gradient elution, the enzyme lost about 50% of its activity during a 1-h incubation at pH 4.8. However, Western-blot analysis indicated no appreciable enzyme degradation. Re-chromatography of CWI peak fractions on SPS using NaCl-gradient elution showed the presence of a 17-kDa peptide (p17) in fractions with low CWI activity but strong CWI immunosignal (Weil and Rausch 1994, Planta 193, 430-437). When separating CWI from p17 by Concanavalin A (Con A)-Sepharose chromatography, inhibition could be restored by incubating the inhibitor-containing fraction with inhibitor-free CWI. More than 90% of CWI could be inhibited, suggesting that all CWI was susceptible to p17 binding. The presence of divalent metal ions (Ca2+, Mg2+, Zn2+) during pre-incubation of CWI with p17 reduced CWI inhibition substantially. Also, sucrose protected CWI against inhibition by p17 (half-maximum protection at 1.3 mM). Binding of p17 to CWI during a 1-h pre-incubation was pH-dependent, pH 4.5 causing maximum inhibition, whereas at pH 6.5 no inhibition was observed. Gel-permeation chromatography revealed that the native inhibitor acts as a monomer. Immunoprecipitation of CWI co-precipitated p17, confirming direct binding of p17 to CWI. When fractions containing CWI and p17 were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and subsequent Western blotting a diffuse immunosignal of 86-90 kDa was observed (in addition to the prominent CWI signal at 69 kDa).(ABSTRACT TRUNCATED AT 250 WORDS)

[Intravenous immunoglobulins in bronchial asthma: a therapeutic alternative?]

Treatment of severe bronchial asthma usually requires the use of steroids. Given the known side effects of steroid treatment, potential alternative therapeutical strategies are currently evaluated; among others, intravenously administered immunoglobulins (ivIg) may be considered. In one study of 5 children with bronchial asthma and IgG subclass deficiency, an improvement of asthma was demonstrated in 4 out of the 5 patients under ivIg treatment over several months. In another study on ivIg treatment in 8 immunocompetent children with steroid-dependent asthma, there also was an improvement of asthma, leading to a reduction in the required steroid dose; furthermore, there was a diminution in skin prick test reactivity. At present, only speculations can be made about the possible mechanisms of action.

Does pertussis infection induce manifestation of allergy?

To evaluate whether pertussis induces the development of allergy, a prospective study was performed in 25 children aged 0.8-12.2 years. The patients underwent allergy diagnostics during pertussis infection and at a follow-up visit 8-14 months later. Diagnostic criteria included the medical history of the patients and their families, a modified skin prick test, measurement of serum IgE and radio-allergosorbent test screening for specific sensitizations. At the time of pertussis, serum IgE concentration in the study group was 62 +/- 30 kU/ml. At the follow-up visit, there was a significant increase in serum IgE to 137 +/- 51 kU/ml, which was also significantly higher than IgE in an age-matched control group. Children at a significantly higher risk for developing IgE increase or new allergic sensitizations were those with a family history of allergy or potentially allergic disease in their personal history. Our results indicate that pertussis may induce IgE production in affected children.

Mucus hypersecretion in bronchiectasis. The role of neutrophil proteases

To investigate the role of neutrophil proteases in the pathogenesis of mucus hypersecretion in bronchiectasis, we collected sputum samples from seven patients with bronchiectasis and measured their secretagogue activity by examining secretion of radiolabeled macromolecules by bovine airway submucosal gland cells incubated with sputum supernatants. There was marked secretagogue activity in bronchiectasis sputum, reaching a maximum of 1,963 +/- 292% (mean +/- SEM) above baseline at 1:15 dilution. Addition of ICI 200,355 (10(-5) M), a selective human neutrophil elastase inhibitor, decreased the secretory response markedly (72.53 +/- 5.89% reduction). The combination of aprotinin, an inhibitor of cathepsin G, and ICI 200,355 caused significantly more reduction in the secretory response than ICI 200,355 alone (89.12 +/- 3.8 versus 72.53 +/- 5.89% reduction, p < 0.05). We conclude that bronchiectasis sputum causes a large secretory response from tracheal submucosal glands due mostly to neutrophil proteases.

Role of neutrophil elastase in allergen-induced lysozyme secretion in the dog trachea

To test our hypothesis that neutrophil elastase plays a role in airway hypersecretion associated with the allergic late-phase response, using an isolated tracheal segment system in vivo and measuring lysozyme activity in the perfusate of the lumen as a marker of submucosal gland secretion over 8 h, we studied the response of five allergic dogs to ragweed. The dogs were exposed on separate occasions to specific allergen, to allergen vehicle, and to allergen in the presence of a selective neutrophil elastase inhibitor, ICI 200,355. Allergen exposure caused a marked increase in lysozyme secretion that was significantly increased at 4, 6, and 8 h compared with controls and ICI 200,355-treated dogs. Neutrophil elastase appeared in the perfusate after allergen exposure and was positively correlated with lysozyme secretion at 8 h. These findings suggest that neutrophil elastase plays an important role as a secretagogue in the allergic late-phase response.

Neutrophil elastase stimulates tracheal submucosal gland secretion that is inhibited by ICI 200,355

To investigate whether human neutrophil elastase (HNE) stimulates airway submucosal gland secretion, we studied the effect of purified HNE on secretion of 35S-labeled macromolecules from isolated tracheal tissues from ferrets, dogs, and humans. HNE stimulated secretion in a concentration-dependent fashion, the secretory response being most pronounced in ferret tissues with a maximal response of 1,498 +/- 384% above baseline at 10(-5) M. In dog tissues, maximal secretory responses (509 +/- 169%) to HNE were much greater than to bethanechol (80 +/- 26%). Human tissues obtained several hours postmortem still responded to HNE (179 +/- 48% at 10(-5) M) significantly more than to the combination of isoproterenol, phenylephrine, and bethanechol (23 +/- 10%). Morphometric analysis of canine tracheal tissues showed degranulation of submucosal gland cells after HNE. A specific inhibitor of HNE (ICI 200,355) potently inhibited secretory responses in a concentration-dependent fashion. We suggest that HNE in airways of patients may cause hypersecretion and that treatment with ICI 200,355 may provide a strategy for therapeutic intervention.

Cytostatic synergism between bromodeoxyuridine, bleomycin, cisplatin and chlorambucil demonstrated by a sensitive cell kinetic assay

Bromodeoxyuridine/Hoechst flow cytometry was used to analyse the interference of common cytostatic agents with cell activation and cell cycle progression of human B-cell lines. Bleomycin impaired both cell activation and G2 transit, the latter effect being oxygen dependent. The DNA alkylating agents cyclophosphamide, chlorambucil and mitomycin C caused G2 arrest, whereas cisplatin arrested cells in both the S and G2 phase of the cell cycle. Vinblastin interfered with mitosis, but in addition arrested cells in all phases of the cell cycle. The growth inhibitory action of bleomycin, cisplatin and chlorambucil was dependent upon the bromodeoxyuridine (BrdU) concentration in the culture medium. No interaction was found between BrdU and cyclophosphamide, mitomycin C and vinblastin. The cell cycle kinetic mechanism of the interaction between BrdU and bleomycin, cisplatin and chlorambucil was a potentiation of the G2 arrest. In conclusion, BrdU may be useful in clinical chemotherapy as a chemosensitizer for selected cytostatic agents.

Control of proven pulmonary and suspected CNS aspergillus infection with itraconazole in a patient with chronic granulomatous disease

An 11-year-old boy with chronic granulomatous disease caused by cytochrome b deficiency developed right upper lung lobe aspergillosis. Intracerebral lesions developed on maximum doses of flucytosine and amphotericin B. Treatment with 16 mg/kg oral itraconazole was followed by a dramatic clinical improvement and almost complete disappearance of the intracerebral lesions. Plasma itraconazole levels were between 40 and 3440 ng/ml depending on concomitant medication. Toxicity was restricted to transient elevation of alkaline phosphatase and gamma glutamyl transferase. We conclude that further trials with itraconazole are justified in high risk patients in whom conventional therapy has failed.

Immunocytochemical localization of arachidonate 15-lipoxygenase in erythrocytes, leukocytes, and airway cells

In reticulocytes, the enzyme 15-lipoxygenase (15-LO) is believed to contribute to cellular differentiation, and in leukocytes and airway cells 15-LO generates inflammatory mediators. The recent availability of antibodies to 15-LO now allows us to determine which specific cells contain the enzyme, to characterize its subcellular localization, and to determine its expression at the translational level. A polyclonal antibody to recombinant human reticulocyte 15-LO was used with a standard immunofluorescent technique. In rabbit red blood cells, fluorescence appeared during the course of anemia. Early reticulocytes did not fluoresce, but more mature reticulocytes showed increased fluorescent intensity. Late reticulocytes contained little fluorescence. Among human leukocytes, only eosinophils fluoresced. In human trachea, 15-LO immunofluorescence was localized to epithelial cells, and both basal and ciliated cells fluoresced. In all cells studied, fluorescence was localized to the cytoplasm and was variable in degree among cells in each preparation. We conclude that the 15-LO of airway cells and eosinophils is immunologically related to the reticulocyte 15-LO. Furthermore, the variable fluorescence among cells (e.g., in epithelium) and during development (e.g., reticulocytes) suggests a role of 15-LO in cell growth and development.

[Combined hypophyseal function test in children with homozygous beta-thalassemia]

Nowadays, endocrine problems like retarded sexual maturation and growth deficiency, lead to substantial suffering in patients with beta-thalassemia major. The aim of the present study is the differentiation between a possible insufficiency of the pituitary gland and dependent target organs, respectively. 12 patients (age 1.9-18.10 years) were examined by means of a combined pituitary function test. The corticotropic axis turned out to be normal as shown by a regular stimulation of cortisol in all patients tested. The thyrotropic function was unaffected in all children: elevated levels of TSH pointed to primary hypothyroidism. Pubertal values of LH and FSH were found in only 3 out of 7 patients at pubertal age. In 10 out of 12 children, stimulation led to a rise in STH levels above 10 ng/ml. On the whole, there was no evidence for pituitary insufficiency in beta-thalassemia major.

Influence of short- and long-term inhalation of salbutamol on lung function and beta 2-adrenoceptors of mononuclear blood cells in asthmatic children

Clinical observations have shown that some asthma patients develop tachyphylaxis to beta-sympathomimetic drugs. As down-regulation of the number of beta-adrenoceptors in different human tissues after exposure to catecholamines and beta-adrenergic drugs is well known, we investigated whether a interrelation exists between beta-adrenoceptor down-regulation and clinically detectable beta-adrenergic subsensitivity during beta-sympathomimetic treatment. The following results were obtained: 1. beta 2-Sympathomimetic inhalation treatment with salbutamol in therapeutic doses led to a significant down-regulation of beta 2-adrenoceptors and consecutive cyclic adenosine monophosphate response to isoprenaline. This effect was already detectable after short-term treatment of 3-7 days in 9 asthmatic children. 2. In the long-term study over 6 months, salbutamol inhalation in 12 asthmatic children led to a significant down-regulation of beta-adrenoceptor binding sites on mononuclear blood cells (MNC) from 1539 +/- 91 to 1115 +/- 99 after 14 days, remaining in this range thereafter. 3. The mean airway resistance (Raw) of these 12 patients decreased significantly within 14 days from 8.1 +/- 0.8 to 5.7 +/- 0.5 cm H2O/l/s to remain stable throughout the 6 months of salbutamol treatment. The differences in Raw before and immediately after inhalation of 0.2 mg salbutamol (2 puffs) were unchanged during the study period. It is concluded, that long-term inhalative treatment with salbutamol over a period of 6 months does not result in refractoriness to beta-adrenergic drugs in the airways of asthmatic children, even though a significant down-regulation of beta 2-receptors on peripheral MNC occurs.

Evaluation of experimental combined toxicity by use of dose-frequency curves: comparison with theoretical additivity as well as independence

Dose-frequency curves of toxic effects of a substance A were evaluated in the absence and in the presence of a fixed dose of a second substance B. Data were fitted by the curve-fitting program ALLFIT. Observed combined frequencies of A + B were compared statistically with the expected frequencies of additivity and (or) independence by the phi 2-square goodness-of-fit test. The theoretical dose-frequency curves expected for an additive response were obtained by a solely graphical procedure and the theoretical curves for independent effects were calculated from the effects of B and A at certain doses. In rotarod tests with trained mice, the combined deteriorating effect of ethanol and benzodiazepines were significantly over-additive. However, their lethal interaction appeared underadditive in mice. The lethal underadditive interaction of ethanol and phencyclidine (PCP) can be ascribed largely to independent actions of these compounds. Loss of righting reflex was additively enhanced by PCP, whereas PCP overadditively enhanced the effect of ethanol. The insecticidal action of the cholinesterase inhibitors malathion and parathion appeared additive and significantly different from independent interaction. A comparison of results from dose-response curves with isoboles showed good agreement. The method appears as an attractive alternative or as a complementary procedure to the isobolographic analysis. Combination experiments as described can be carried out and evaluated rather simply, with a minimum of expenditure and a maximum of information.

[Urological aspects of non-urological tumor in the lesser pelvis]

The surgical outcome in 30 patients with advanced pelvic malignancies of nonurological origin infiltrating the urinary tract was analyzed. The pelvic mass was totally removed by multivisceral resection in 15 patients, and incompletely removed in 11 patients; 4 patients underwent only palliative treatment in the form of urinary diversion, because of unresectable tumors. Mortality, morbidity, survival rates and quality of life were evaluated and showed significant differences. The best results were achieved in the group with complete excision of pelvic viscera. Patients treated with incomplete resection or palliative urinary diversion because of unresectable mass had a poor outcome.

Solubilization of multilamellar liposomes of egg yolk lecithin by the bile salt sodiumtaurodeoxycholate and the effect of cholesterol--a rapid-ultrafiltration study

The solubilization of multilamellar egg yolk lecithin liposomes by sodiumtaurodeoxycholate in aqueous phase was studied by ultrafiltration as a function of time, bile salt and cholesterol concentration. The corresponding equilibrium states were analysed. Complete solubilization was achieved at total bile salt/lecithin molar mixing ratios of approximately 5. The minimum ratio to start solubilization was 0.1, corresponding to a free bile salt concentration of only 5% of the critical micelle concentration (CMC). Mean equilibrium constants for the partition of bile salts between non-filterable aggregates and filterable mixed micelles and also the free bile salt concentration were determined. Sodiumtaurodeoxycholate had a higher affinity for small mixed micelles than for lamellar mixed aggregates especially in the presence of cholesterol, which reduces the degree and rate of the solubilization process. A non-homogeneous distribution of bile salts in the lipid phase was detected at low bile salt concentrations.

Pain in newborns and prematures: current practice and knowledge

No unambiguous answer can be given as to whether newborns are able to feel pain similar to that experienced by older children and adults. However, there are several lines of evidence--anatomical, physiological and behavioral--which substantiate the possible presence of distressing nociceptive activity in the full-term and preterm neonate. Although the efficacy and safety of anesthesia in newborns and prematures has repeatedly been demonstrated, there are still numerous recommendations and current practices, based on antiquated theories, that withhold adequate medications from neonates during surgery. Even if the emotional and cognitive aspects of nociception in the newborn remain a subject of speculation giving rise to philosophical discussions as to the correct terminology, it is the mandate of newborns' physicians to provide the best possible therapy to their patients and to protect them from distress, unease and presumptive pain.

The adrenergic system in lymphocytes from children with cystic fibrosis

Several in vivo and in vitro studies have suggested that children suffering from cystic fibrosis (CF) might have a general defect of beta-adrenoceptors on the cell surface which might account for an unbalanced secretory process. In order to investigate if this view holds true, we determined the beta-adrenoceptor density and affinity on lymphocytes by means of radioligand studies using 125-iodo-cyano-pindolol (125-ICYP) in 20 children with CF. Cyclic AMP (cAMP) response was also investigated after specific beta-adrenoceptor stimulation with isoprenaline (IPN) and after direct stimulation of the adenylate cyclase with forskolin in lymphocytes. Children with CF and controls have identical numbers and affinities of beta-adrenoceptors on lymphocytes. The cyclic AMP response was identical in CF- and in age-matched control children regardless whether adenylate cyclase was stimulated directly or via beta-adrenoceptors. In conclusion, the data support the view that no general adrenoceptor or adenylate cyclase defect exists in CF. As several studies have found abnormal reactions to adrenergic stimuli in CF patients, we presume that there is a defect beyond the level of adrenergic receptors and cAMP which remains to be identified.

[Plasma cell granuloma of the lung and mediastinum in a ten year old girl]

A ten-year-old girl presented with an asymptomatic tumor of the lung. X-ray morphology suggested malignancy. Laboratory investigations revealed hypochromic anaemia, strong signs of inflammation, and hypergammaglobulinaemia. By means of surgery the tumor was completely removed. Histologic analysis established the diagnosis of a plasma cell granuloma. Postoperatively, laboratory parameters normalized. During the follow-up period of now 30 months there has been no relapse.

Spontaneous renocolic fistula secondary to calculous pyonephrosis

A rare case of spontaneous renocolic fistula is described, and the literature is reviewed.

Status of plasma and erythrocyte fatty acids and vitamin A and E in young children with cystic fibrosis

The fatty acid (FA) status in young children with cystic fibrosis (CF) was investigated. The FA composition of the plasma cholesterol esters (CE) and phospholipids (PL) and of the erythrocyte phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was estimated in 11 patients with CF and pancreatic insufficiency (median age, 3.0 years; range, 3 months to 7 years) and in 10 age-matched controls. Linoleic acid values ranged widely but were not significantly reduced in the patients. However, arachidonic acid (20:4w6) and docosahexaenoic acid were decreased in all lipid classes. The ratio of dihomo-gamma-linoleic acid to arachidonic acid (20:3w6/20:4w6) was significantly increased in the patients, indicating an impairment of FA metabolism (delta 5-desaturation). Plasma retinol concentrations were normal and did not differ between the supplemented patients and controls. Plasma total tocopherols and alpha-tocopherol and their ratios to total lipids were significantly reduced in the CF patients, but all values were within the normal ranges for the pediatric age group, and no child met the criterion for vitamin E deficiency.

Structure and thermodynamics of the dihexadecylphosphatidylcholine-water system

X-ray small- and wide-angle diffraction, differential scanning calorimetry (DSC), temperature scanning densitometry (TSD) and electron microscopy were used to study the lyotropic and thermotropic properties of the system 1,2-O-dihexadecyl-sn-glycero-3-phosphocholine-water over a wide range of compositions from the dry lipids to a large excess of water, and in the temperature range between 0 degrees C and 150 degrees C. The results were used to construct a temperature-composition phase diagram. The phases have been characterized with respect to their molecular arrangements and hydrocarbon chain packing subcells. In the fully hydrated state (greater than 45 wt% H2O) four thermotropic phases were found, with readily reversible transitions at 5 degrees C, 32.5 degrees C and 43.6 degrees C, respectively. The two lower temperature phases deviate from all others in consisting of bilayers with fully interdigitated hydrocarbon chains, while above 32.5 degrees C the structures resemble closely those of the analog diester lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). At hydrations between 30 and 45 wt% H2O, and below 32 degrees C, interdigitated and non-interdigitated multilayers coexist in one coherent phase. A bilayer tilting mechanism is proposed for the formation of this coexistence of two regular structures. Below 30 wt% H2O, hydrated 1,2-O-dihexadecyl-sn-glycero-3-phosphocholine (DHPC) exists in lamellar, non-interdigitated bilayers, showing very weak interbilayer swelling. There, the water molecules appear to occupy voids between the polar headgroups.

Thermal phase behaviour and structure of hydrated mixtures between dipalmitoyl- and dihexadecylphosphatidylcholine

Mixtures of 1,2-dipalmitoyl- and 1,2-O-dihexadecyl-sn-glycero-3-phosphocholine (DPPC and DHPC) in dispersion with excess water were studied by differential scanning calorimetry (DSC) and X-ray diffraction techniques. The transition parameters of the main gel-to-liquid crystalline transition show a monotonous dependence on the composition, indicating ideal miscibility of the two lipids, in keeping with the closely similar structures of the pure, hydrated lipids in the P beta' and L alpha states. The pre-transition shows a depression to a minimum temperature of 23 degrees C occurring around equimolar mixtures. Below the pre-transition temperatures, the L beta' gel phase of DPPC maintains bimolecular structure up to DHPC admixtures of 50 mol%, with adaptations in hydrocarbon chain packing and multilayer periodicity. On the side of DHPC, the interdigitated gel structure shows full solubility for DPPC up to equimolarity without major structural changes. The crystalline Lc-phase of DPPC exhibits immiscibility with DHPC, demonstrated by the fact that the subtransition is abolished already at less than 15 mol% DHPC. DHPC, below its subtransition, can accommodate up to 50 mol% DPPC within an interdigitated layer structure with unperturbed, crystalline hydrocarbon chain packing.

Role of lipid peroxidation in the toxicity of T-2 toxin

Recent reports suggest that lipid peroxidation may be involved in the toxicity of T-2 toxin. In the present study the influence of T-2 toxin on two parameters of lipid peroxidation was examined: the formation of thiobarbituric acid reactive material in isolated hepatocytes and liver homogenates from rats and ethane exhalation in vivo. In isolated hepatocytes there was no significant increase in thiobarbituric acid reactive material, neither after addition of T-2 toxin in vitro nor when the toxin had been applied to the rats 15 hr before preparation of hepatocytes. In liver homogenates the amount of thiobarbituric acid reactive material was increased up to 50% over the controls, depending on the dose of T-2 toxin. The increased values are difficult to interpret, because the extent of the increase depends on the method used for determination of thiobarbituric acid reactive material. Measuring another parameter of lipid peroxidation, i.e. ethane exhalation, there was no difference between the T-2 toxin treated rats and the controls whereas carbon tetrachloride treated rats exhaled high amounts of ethane. These results suggest that lipid peroxidation does not play a major role in T-2 toxin toxicity.

[Further Compounds from Centaurea stoebe.]

From CENTAUREA STOEBE the following compounds have been isolated: cnicin, salonitenolide, salonitenolid-8- O-(4'-acetoxy-5'-hydroxyangelate), stoebenolide, 3-hydroxy-2-methylbutyrolactone, and 3-(3, 4-dihydroxy-5-methoxyphenyl)-prop-1-yl 3-hydroxy-11-methyloctadecanoate.

A Low Molecular Weight Polypeptide Which Accumulates upon Inhibition of Porphyrin Biosynthesis in Maize

Levulinic acid, an inhibitor of porphyrin biosynthesis, causes marked accumulation of a low molecular weight polypeptide in greening maize (Zea mays L.) leaves. Additional compounds which interfere with porphyrin synthesis (e.g. aminooxyacetate, iron-chelators, 4,6-dioxoheptanoic acid) had a similar effect. The polypeptide accumulated in the cytosol and could not be detected in the plastid stroma. Its molecular weight was estimated as 4800 daltons by electrophoresis in sodium dodecyl sulfate-acrylamide gels containing urea and glycerol. The accumulation of the polypeptide did not result from inhibition of chlorophyll or protoheme syntheses. Compounds which caused its accumulation markedly reduced the activity of nitrite reductase. It is suggested that the accumulation is caused by inhibition of siroheme synthesis which interferes with the formation of nitrite or sulfite reductase.

Affinity of various ligands for benzodiazepine receptors in rat cerebellum and hippocampus

The structure-affinity relationship of benzodiazepine receptor ligands for binding to their receptors was investigated by measuring the potency of 41 benzodiazepines or benzodiazepine analogues and of 9 non-benzodiazepines for inhibition of [3H]flunitrazepam binding to cerebellar or hippocampal membranes. It was found that a chloro or a fluoro substitutent in position 2' enhanced whereas substituents in position 3 and substituents larger than a methyl group in position 1 of the benzodiazepine ring system reduced the potency of benzodiazepines for inhibition of [3H]flunitrazepam binding in cerebellum or hippocampus. In addition, several benzodiazepines could be identified which have a higher affinity for benzodiazepine receptors in cerebellum than for those in hippocampus. A selectivity of benzodiazepines for their receptors in cerebellum seems to be caused not only by certain substituents in position 1 but also by a chloro group in position 2' and together with this substituent by a hydroxy group in position 3.

Ribonucleic Acid and Protein Metabolism in Pea Epicotyls : III. Response to Auxin in Aged Tissue

Applications of auxin to the tips of intact aged pea Pisum sativum L. var Alaska epicotyls resulted in an increase in the content of polyribosomes and poly(A) and in the capacity of isolated polysomes to support protein synthesis in vitro. Few changes were seen in the two-dimensional gel patterns of silver-stained proteins accumulated (or degraded) in vivo even after 15 hours of auxin treatment. In contrast, substantial changes were evident in the two-dimensional gel fluorographs of polypeptides generated in vitro by total RNA and by polysomal RNA from tissue treated with auxin for only 6 hours. Of the 200 spots resolved by fluorography, total RNA from auxin-treated tissue generated 33 spots with increased intensity and 10 with decreased intensity; polysomal RNA yielded 33 spots which increased and only three that decreased. In general, the polypeptides that increased in intensity were higher molecular weight and those that decreased were lower molecular weight. These changes occurred prior to growth and might be prerequisite for the auxin-induced slow growth response seen in this aged tissue.Comparisons were made between the changes in RNA and protein metabolism occuring during aging and after wounding and auxin treatment of aged tissue. Aging causes a decline in poly(A), polysomes, and protein synthesizing capacity, whereas wounding and auxin treatment cause increases. Wounding appears to act primarily at the level of translation, whereas auxin has a greater effect on transcription. It is argued that the use of excised tissue to study auxin effects on RNA and protein metabolism should be avoided.

Incorporation of haem into phycocyanobilin in levulinic acid treated Cyanidium caldarium

Cells of the red alga Cyanidium caldarium were preincubated with 5 mmol 1(-1) levulinic acid (LA) and subsequently incubated with (14)C-labelled haem (5.67 Bq nmol(-1)). Phycocyanin was isolated. The specific radio-activity of its chromophore phycocyanobilin (PCB) was determined after cleavage and purification by thin layer chromatography. The percentage of PCB formed from labelled haem within 0.5 h was considerably higher in LA treated cells than in non-treated controls. This difference disappeared after prolonged incubation (16.5 h) with haem. The results are interpreted as possible incorporation of haem into preexisting apoprotein.