Electrochemically Initiated Synthesis of Methanesulfonic Acid

The direct sulfonation of methane to methanesulfonic acid was achieved in an electrochemical reactor without adding peroxide initiators. The synthesis proceeds only from oleum and methane. This is possible due to in situ formation of an initiating species from the electrolyte at a boron-doped diamond anode. Elevated pressure, moderate temperature and suitable current density are beneficial to reach high concentration at outstanding selectivity. The highest concentration of 3.7 M (approximately 62 % yield) at 97 % selectivity was reached with a stepped electric current program at 6.25-12.5 mA cm^-2 , 70 °C and 90 bar methane pressure in 22 hours. We present a novel, electrochemical method to produce methanesulfonic acid, propose a reaction mechanism and show general dependencies between parameters and yields for methanesulfonic acid.

In Situ Synchrotron X-ray Diffraction Studies of the Mechanochemical Synthesis of ZnS from its Elements

Mechanochemistry, as a synthesis tool for inorganic materials, became an ever-growing field in material chemistry. The direct energy transfer by collision of the educts with the milling media gives the possibility to design environmental-friendly reactions. Nevertheless, the underlying process of energy transfer and hence the kinetics of mechanosynthesis remain unclear. Herein, we present in situ synchrotron X-ray diffraction studies coupled with pressure measurements performed during the formation of ZnS and the subsequent phase transition (PT) from the hexagonal to the cubic modification. Milling Zn and S₈ results in the sublimation of S₈ , observed by a sudden pressure increase. Simultaneously, the hexagonal metastable ZnS-modification (wurtzite) forms. Via detection of the pressure maximum, the exact start of the wurtzite formation can be determined. Immediately after the formation of wurtzite, the structural PT to the thermodynamic stable cubic modification sphalerite takes place. This PT can be described by the Prout-Tompkins equation for autocatalytic reactions, similar to thermally induced PT in sulfur vapor at high temperatures (T>1133 K). The increase in the reactivity of the wurtzite formation is explained by the reaction in sulfur vapor and the induction of defect structures by the collisions with the milling media.

In Situ Synchrotron X-ray Diffraction Studies of the Mechanochemical Synthesis of ZnS from its Elements

Invited for the cover of this issue is Claudia Weidenthaler and co-workers at the Max-Planck-Institut für Kohlenforschung, Shenzhen University and Deutsches Elektronen Synchrotron. The image depicts the X-ray diffraction results showing the formation of ZnS and the subsequent phase transition from the hexagonal to the cubic modification. Read the full text of the article at 10.1002/chem.202101260.

Measuring the Cost Effects of Modular Product Architectures — A Conceptual Approach

Modular product architectures offer a solution for the trade-off between offering the market a wide variety of products and improving a company’s internal cost situation. However, individual cost effects that determine the extent to which modularity should be applied to product architecture are widely unknown in industry. In this paper, we develop a conceptual approach to provide suggestions for improving an examined modular product architecture from a cost perspective. Our work makes an important contribution: The conceptual approach accentuates which steps are necessary in order to recommend whether the product architecture’s current degree of modularity should be enhanced or diminished.

A framework for benchmarking product sustainability efforts

Purpose

– Regulatory pressure, consumer awareness, and the quest for competitive advantage place sustainable products in today’s decision-making spotlight. The purpose of this paper is to explore supply chain dynamics as they relate to sustainable product programs and to empirically develop a framework to align efforts across the supply chain to bring sustainable products to market.

Design/methodology/approach

– Grounded in systems design, stakeholder theory, and the theory of planned behavior, the authors conduct an inductive empirical study of 28 European and US companies.

Findings

– The authors make three contributions. First, the authors identify six dimensions of product sustainability, which map to the Greenhouse Gas Protocol’s sustainability scope model. Second, the authors model relational dynamics using systems diagrams to provide a framework that: first, communicates a common understanding of product sustainability; and second, facilitates tradeoff analysis. Third, the authors elaborate behaviors needed to reduce ambiguity and compliance costs.

Practical implications

– Managers can use the framework to assess product sustainability and evaluate tradeoffs across product dimensions and supply chain participants. Using this insight, managers can design sustainable product programs that engage supply chain participants.

Social implications

– By identifying dimensions, defining costs, and uncovering tradeoffs, managers can more effectively implement sustainable product programs.

Originality/value

– The framework provides a much needed source of clarity to mitigate role ambiguity, reduce compliance costs, and promote collaborative behavior in bringing sustainable products to market.

Anin situpowder diffraction cell for high-pressure hydrogenation experiments using laboratory X-ray diffractometers

Anin situdiffraction cell is presented which has been designed and constructed for in-house powder diffraction experiments under high gas pressures up to 30 MPa. For a proof of principle, thein situcell has been tested for several hydrogenation experiments under elevated pressures and temperatures. LaNi5was chosen as an example for hydrogenation, applying simultaneously 5.5 MPa H2pressure at a temperature of 423 K. For testing the high-pressure–temperature suitability of thein situcell, pressure–temperature experiments up to 14 MPa at 373 K were performed, studying the rehydrogenation of NaH and Al to NaAlH4. The experimental setup enables recording ofin situX-ray diffraction data on laboratory instruments with short data acquisition times at elevated hydrogen pressures and temperatures.

Abstract LB-308: Combination of CTx-0294945 a highly selective inhibitor of focal adhesion kinase with bevacizumab in pre-clinical models of breast cancer

Background: Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that provides a critical hub for signalling from at least four different classes of cellular sensing mechanisms including growth factor receptors, GPCRs, integrins and mechanical stress forces. By temporal and spatial integration of signals from these sources, FAK plays a central role in cell migration, invasion and proliferation; processes vital for tumorigenesis. The significance of FAK to the function of signal transduction pathways provides a strong rationale for the combination of FAK inhibitors with other targeted agents to achieve improved efficacy against a range of cancers. Others have demonstrated the importance of FAK in angiogenesis and therefore combining a FAKi with anti-VEGF agents is attractive as it employs two complementary mechanisms of suppressing the formation of tumor vasculature. Here we present results from the co-administration of CTx-0294945, a highly selective FAKi, and bevacizumab (bev) in an orthotopic model of human breast cancer. Methods and Results: CTx-0294945 is an orally bioavailable small molecule ATP competitive inhibitor of focal adhesion kinase (FAK KD=0.21 nM). It exhibits high selectivity against a diverse panel of 125 kinases including the closely related Pyk2. CTx-0294945 inhibits autophosphorylation of 397Y-FAK in MDA-MB-231 cells with an IC50 = 7 nM and exhibits low general cellular toxicity (IC50 = 2.7 µM, MDA-MB-231 cells). CTx-0294945 is suitable for oral administration (%F=58 and t1/2=5.1 h at 20 mg/Kg in rat) and does not inhibit (IC50 >20 µM) any of the cytochrome p450 isoforms tested to date. To assess the co-administration of CTx-0294945 with bev, mice were injected orthotopically with MDA-MB-231 cells (106). After 14 days, when tumors were palpable, mice were randomized into 4 groups and dosing commenced. The groups were treated with CTx-0294945 (80 mg/kg QD, PO), bev (12.5 mg/Kg IP, x2/week), CTx-0294945 (80 mg/Kg QD, PO) and bev (12.5 mg/Kg IP, x2/week) or vehicle. Tumor growth was monitored and on day 28 animals in the vehicle and CTx-0294945 arms were culled when the size of the tumors reached ethical end point (1000 mm3). Tumor growth in the bev only and the CTx-0294945 + bev arms was significantly inhibited (75% and 88% TGI respectively). At this time the treatment regimes for both cohorts were stopped and tumor growth allowed to progress. After an additional 14 days the experiment was terminated when the bev treatment group reached ethical end point; however the average size of the tumors in the CTx-0294945 + bev cohort was still was only 562 mm3. Conclusions: Our data suggest the potential utility of combining a selective FAK inhibitor with bevacizumab to prevent tumour progression and enhance the durability of response.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-308. doi:1538-7445.AM2012-LB-308

Sex difference in target seeking behavior of developing cremaster muscles and the resulting first visible sign of somatic sexual differentiation in marsupial mammals

Cremaster muscles are present in both male and female developing and adult marsupial mammals. They are complex structures and composed of several distinct bundles of striated muscle fibers provided with: (1) a distinct and extensive innervation; (2) a distinct blood vascular supply; (3) a distinct tendineous origin on the anterosuperior iliac spine; and (4) distinct target structures. The muscles thus seem to be separate anatomical entities and not a part of one or more of the layers of the ventral abdominal wall musculature. Cremaster muscles in males are elongated, are larger than in females, and for the most part are a component of the funiculus spermaticus. They insert on the distal part of the tunica vaginalis. The distal parts of the muscles in females are flattened ("fan shaped") and insert over a broad area on the dorsal borders of the mammary glands. Muscles in males have no relation whatsoever to the male mammary glandular rudiments. Muscles in females are attached at the base of the uterine round ligament. The remarkable sex difference in target structures of marsupial cremaster muscles becomes noticeable during perinatal life when outgrowing muscles take a different path in males and females. The initial appearance of this sexually dimorphic trait precedes the sexual differentiation of the genital ducts and external genitalia. In fetal males, the cremaster muscles grow in the direction of the site where scrotal bulges initially appear in the subcutaneous layers and later on the inguinal skin surface. They also take the gubernacular core of the ventral abdominal wall and the attached peritoneal epithelium with them during this outgrowth process. Consequently, this results in the development of a slitlike evagination of the abdominal lumen as the primary step to development of the processus vaginalis, while the testis and adjacent mesonephros and its duct are still attached to the posterior abdominal wall. In fetal females, the outgrowing cremaster muscles pass along the gubernacular core and, subsequently, this structure develops further as the tip (attached to the tubo-uterine junction) of the intra-abdominally protruding and further developing uterine round ligament. The female cremaster muscles grow further into caudal direction to shape a dorsal border of the developing mammary glands. The early onset of this sexually dimorphic outgrowth of cremaster muscles indicates that the "classical hormones" of sexual differentiation (anti-Müllerian hormone [AMH] and steroidal androgens) are not involved in this process. It could thus depend on primary genetic control with male development associated with the male-limited activity of genes on the Y-chromosomes and female development as the default process. Alternatively, the process in males could be under the control of an as yet unidentified third fetal testicular hormone involved in sexual differentiation processes which must then show an unexpectely early (i.e., perinatal) onset of its secretion.

Bilateral cryptorchidism in a dog with persistent cranial testis suspensory ligaments and inverted gubernacula: report of a case with implications for understanding normal and aberrant testis descent

The genital system of a dog with bilateral intra-abdominal testes is described. External virilisation was normal except for an empty scrotum. Internally there was a prostate of normal macroscopic and histological appearances and, bilaterally, a fully developed male genital tract. Testicular vasculature was normal. Cranial to each testis, there was a strong ligament lying at the free edge of the gonadal/genital mesentery and running between the cranial tip of the testis/epididymis and the area craniolateral of the ipsilateral kidney. It was impossible to push the testes into the inguinal canal because of this strong ligament. Caudal to each testis, there was an elongated whitish structure between the caudal pole of the epididymis and the area of the internal inguinal ring. On closer inspection this structure appeared to be the inverted and elongated processus vaginalis sac. There was a minor ligament at the free border of the inguinal fold of the genital mesentery between the tip of this inverted processus vaginalis and the adjacent junction of the cauda epididymidis and vas deferens. The findings suggest that persistence of the fetal cranial gonadal suspensory ligaments could have been the major aetiological factor in this case of cryptorchidism. Their persistence could have prevented caudal outgrowth of the processus vaginalis with its consequent development into an intra-abdominal papilla-like structure. Inappropriate persistence of the cranial suspensory ligaments in male rodents, pig, and cattle has been associated with insufficient exposure of their primordia to androgen during fetal life. It is uncertain whether a similar deficiency could underlie persistence of these structures in the present specimen. The findings add further weight to the hypothesis that regression of the cranial gonadal suspensory ligament in males is a key event in the process of testis descent. The human homologue of this ligament deserves more attention in the analysis and treatment of human cryptorchidism.

Nerve supply of the proximal sesamoid bone in the horse

In chronical proximal sesamoid bone lameness it is difficult to localise the exact site of pain. A specific diagnostic analgesia is not available because of a deficiency of detailed information about the nerve supply to the proximal sesamoid bones and surrounding area. A macroscopic study of the nerve distribution to the proximal sesamoid bones of 10 foals and 5 adult horses revealed that these bones are innervated by two branches, in this study called the medial and lateral sesamoidean nerve, respectively, originating from the medial and lateral palmar nerve. Histology of the left forelimbs of two fetuses and one foal confirmed the macroscopic findings. Additionally, histology of ten proximal sesamoid bones of adult horses showed that myelinated nerve fibres are present in the nutrient foramina and in the trabecular bone, accompanying the larger arteries. This study provides possibilities for future diagnostics of proximal sesamoid bone lameness by specific local perineural analgesia.

Over-expression of cellular oncogenes in cystadenocarcinomas of the ovary

A complex analysis of oncogene over-expression in ovarian cystadenocarcinomas of 20 patients was performed. Radioactively labelled cDNAs were synthesized from total cellular RNA from tumor cells and hybridized to dot blot filters. On each filter more than 20 different plasmids containing cloned oncogene fragments were immobilized. In concordance with published data fms was found over-expressed in 40% of the tumors. Elevated expression levels of the EGF receptor was also frequently detected. 35% of the tumors showed elevated N-ras mRNA levels. All those tumors' showed a highly dedifferentiated phenotype and were classified as G3-tumors. More over, simultaneous over-expression of different oncogenes correlated surprisingly strongly with tumor grading.

[Acarex test and acarosan effect in house dust mite allergy in 2 year follow-up]

Clinical investigations of the effect of the acaricide product Acarosan shows in a large collective of patients beneficial results, whereby the patients are examined up to three months after sanitation. The remaining patients of this study are followed up one and two years after sanitation in open clinical trials. Without exception Acarex test values decrease highly significant after three months, indicating the effective elimination of the house dust mites by Acarosan treatment and consequently the reduction of the allergen containing excreta. The values increase after one year, but after a repetition of the Acarosan treatment they decrease again to the level reached after the first sanitation. The best results are achieved by sanitation of carpets, less favourable results are obtained by treating matresses and upholstered furniture. After sanitation all patients with monovalent house dust mite sensitization report an improvement of their symptoms (eyes, nose, bronchi) up to two years. Drug consumption is variable and decreases over all for up to two years. Peak flow meter values improve in the first year and even further more in the second year. The clinical improvement does not depend on sex, living area or former immunotherapy. During the two year observation period immunologic parameters do not change. 25.6% of the patients show a negative provocation test after the first year and 57% after the second year. Side effects due to the sanitation or signs of sensitization against Acarosan are not observed.

[A rare interstitial lung disease]

Pulmonary lymphangioleiomyomatosis (p.l.) is a rare disease of unknown etiology, and restricted to fertile women. It is characterized by a nodular proliferation of smooth muscle cells in the peribronchial, perivascular and perilymphatic lung tissue, accompanied by cystic dilations of the alveoles, rupture of the alveolar wall, lymphangiectasis, and septal collagen fiber deposition. Radiological-alterations range from enhanced interstitial shadowing to honey comb lung. Common clinical symptoms are progressive dyspnea, pneumothorax, chylous pleural effusion and hemoptysis. Here we present the case of a 43 years old woman, undergoing nephrectomy because of hamartoma of the left kidney, with recurrent pneumothorax and progressive dyspnea, verifying the diagnosis of p.l. by open lung biopsy. Pathogenesis of the disease, differential diagnosis and possible therapeutic approaches are discussed.

[HIV-1 antigenemia and T-cell activation in HIV-1 infected patients]

In order to study a supposed association between T-cell activation in vivo and HIV-1-antigenemia in HIV-1-infected patients, the detection of p24-antigen in sera was correlated to serum levels of beta-2-microglobulin and C1q-binding immune complexes. Anti-p24-antibodies and the urinary excretion of neopterin were also analysed. In 24 of 80 patients (30%) p24-antigen could be detected, and in 15 of 59 (25.4%) there was a loss of anti-p24-antibodies. Tests revealed elevated serum levels of beta-2-microglobulin in 58 of 80 patients (72.5%), elevated levels of C1q-binding immune complexes in 15 of 66 (22.7%), and increased excretion of neopterin in 52 of 60 (86.7%). Detection of p24-antigen, loss of anti-p24-antibodies, serum levels of beta-2-microglobulin, and urinary excretion of neopterin were significantly correlated to advanced stages of HIV-1 infection. Patients with p24-antigen in the serum showed significantly more frequently elevated serum levels of beta-2-microglobulin and no significant association with increased urinary excretion of neopterin. Because of the high proportion of patients with elevated serum levels of beta-2-microglobulin and increased excretion of urinary neopterin in the absence of detectable p24-antigen in serum, we could not correlate HIV-1-antigenemia to T-cell activation in vivo.

[Clinical experiences with cefixime in the treatment of bacterial infections of the lower respiratory tract]

In a prospective, open clinical trial 21 patients suffering from lower respiratory tract infections were treated with the new oral cephalosporin cefixime. The antibiotic was given at a dosage of 200 mg b. i. d. for seven to eleven days. Seventeen of 18 evaluable patients were cured or distinctly improved at the end of therapy as well as two days after the end of treatment. Clinical results correlated well with the results of the lung function tests, especially with the significant decrease of resistance. At the end of therapy all initially isolated pathogens were eradicated. The tolerability of cefixime was good, only in two patients treated mild and transient side effects were noticed (1 x diarrhea, 1 x epigastric pain).

New function of vitamin B12: cobamide-dependent reduction of epoxyqueuosine to queuosine in tRNAs of Escherichia coli and Salmonella typhimurium

Queuosine (Q), 7-[(4,5-cis-dihydroxy-2-cyclopentene-1-yl)-amino)methyl)-7- deazaguanosine, and Q derivatives usually replace guanosine in the anticodon of tRNAs(GUN) of eubacteria and of cytoplasmic and mitochondrial tRNAs of lower and higher eucaryotes except yeasts. Q appears to be synthesized de novo exclusively in eubacteria, and the free-base queuine serves as a nutrient factor for eucaryotes. Recently, a Q derivative, oQ, containing a 2,3-epoxy-4,5-dihydroxycyclopentane ring, has been identified in Escherichia coli tRNA(Tyr). Here we show that oQ is formed when E. coli or Salmonella typhimurium is grown in glucose-salt medium. The formation of oQ was independent of molecular oxygen, and oQ-tRNAs were converted to Q-tRNAs by adding cobalamin to the growth medium. Under strictly anaerobic conditions, considerable amounts of Q were present in E. coli and S. typhimurium tRNAs when the bacteria were grown in the presence of cobalt ions with glycerol as the carbon source and fumarate as the electron acceptor. Under these conditions, the biosynthesis of cobalamin was induced. The results suggest that oQ is derived from ribose and that oQ is finally reduced to Q by a cobamide-dependent enzyme.

Polyamine requirement for microbial protein synthesis: structural specificity in cell-free systems of Escherichia coli

Cell-free protein synthesis was performed with synthetic or natural mRNA in an E. coli system containing physiological concentrations of Ca2, Mg2 and either one or both of the two natural polyamines of E. coli, spermidine and putrescine, or corresponding homologues. Putrescine does not permit poly(U)-dependent poly(Phe) synthesis unless spermidine or nor-spermidine is added. Spermidine supports homopeptide synthesis sufficiently well, its effect being stimulated by putrescine or homologous diamines with increasing chain length from 4 to 7 carbon atoms. Diaminopropane completely inhibits the spermidine-activated system in a competitive manner. Translation of MS2 phage RNA is supported by putrescine, the rate and quality (read through to the termination signal) of translation is optimized by spermidine or triamine homologues. MS2 phage RNA translation is supported by spermidine, putrescine has no further stimulatory effect but diaminoheptane enhances the rate of translation. In this case, however, premature chain termination does occur. The results indicate that spermidine is necessary for optimal poly(U) and MS2 phage RNA translation, that the aminopropyl moiety is important for its function and that the remaining side chain can be extended from C4 to C8. Putrescine may cooperate with spermidine but its chain length is rather critical, it cannot substitute for spermidine. The results indicate that the polyamines facilitate mRNA/tRNA/ribosome interactions in a specific manner.

[Indications for the inhalation provocation test]

For proper performance of BPT certain medicaments must be set off. Kind and duration of inhalation, the time-frequency relation and the dosage of allergens are necessary parameters in evaluation of BPT-results. The BPT is necessary when the history is characteristic without positive skin reaction, when the skin reaction is positive without characteristic history and when several positive skin reactions have been obtained and cannot be excluded as specific for the complaints from the patient history. BPT is the main test in allergic airway diseases to prove an actual clinical allergy together with history and skin tests. RAST correlates differently with BPT with different allergens and does not help much in the house dust group--and mould allergies.

Excretion of polyamines by children with leukemia during chemotherapy

Evidence is presented showing a relation between polyamine concentration and the methylation of tRNA in vitro and in vivo. Polyamine excretion in urine of children with ALL and AML is slightly elevated before the commencement of chemotherapy. Immediately thereafter, excretion of acetylputrescine increases drastically over a period of at least 30-60 days. The elevation seems to be caused by different factors, e.g., destruction of tumor cells, induction of ornithindecarboxylase, and cell recovery after termination of chemotherapy. Acetylspermidine excretion also increases 3-4 days after the beginning of chemotherapy. A positive correlation exists between leukocyte counts and excretion of acetylspermidine. The ratio of acetylspermidine excretion at days 3-4 of the therapy to that before commencement of chemotherapy could be an indicator of response to the therapy.

Regulation of tRNA methyltransferase activities by spermidine and putrescine. Inhibition of polyamine synthesis and tRNA methylation by alpha-methylornithine or 1,3-diaminopropan-2-ol in Dictyostelium

Inhibitors of polyamine synthesis (alpha-methylornithine and 1,3-diaminopropan-2-ol) were used to study the relationship between polyamine synthesis and specific methylations of tRNA in Dictyostelium discoideum during vegetative growth. Polyamine concentrations were found to be 10 mM for putrescine, 1.6 mM for spermidine and 7 mM for 1,3-diaminopropane throughout the growth stage. On treatment of growing amoebae with alpha-methylornithine or with 1,3-diaminopropan-2-ol (each at 5 mM), the syntheses of putrescine, spermidine and 1,3-diaminopropane were arrested within 4h. After polyamine synthesis had ceased, the incorporation of methyl groups into tRNA was considerably decreased under conditions that had no effect on the incorporation of uridine into tRNA, or on net syntheses of protein and of DNA. The following nucleosides in tRNA were concerned: 1 methyladenosine, 5-methylcytidine, 7-methylguanosine, 2-methylguanosine, N2N2-dimethylguanosine and 5-methyluridine (ribosylthymine). The corresponding tRNA methyltransferases, determined in Mg2+-free enzyme extracts, proved to be inactive unless polyamines were added. Putrescine and/or spermidine at concentrations of 10 mM or 1-2 mM respectively stimulate the transmethylation reaction in vitro to a maximal rate and to an optimal extent at exactly the same concentrations as found in vegetative cells. In contrast, 1,3-diaminopropane, which is formed from spermidine, does not affect the methylation of tRNA in vitro at physiological concentrations. Putrescine and/or spermidine stabilize the tRNA methyltransferases in crude extracts in the presence but not in the absence of the substrate tRNA. The results support the view that S-adenosylmethionine-dependent transmethylation reactions can be regulated by alterations of polyamine concentrations in vivo.

On the cytostatic mechanism of cyclophosphamide. Inhibition of aminoacylation of transfer RNA and induction of stringent control in Escherichia coli by 4-hydroperoxycyclophosphamide

4-Hydroxycyclophosphamide, a highly cytotoxic derivative of cyclophosphamide, has bacteriostatic properties at concentrations higher than 80 microM when given to Escherichia coli growing in glucose/salt medium. The inhibitory effect on growth, protein and RNA syntheses is relieved by the addition of a mixture of amino acids, with leucine being obligatory. In cells treated with the drug, aminoacylation of tRNALeu is drastically decreased, but the content of free leucine is not. It is concluded that 4-hydroxycyclophosphamide interferes with the charging process of tRNALeu in E. coli leading to an inhibition of protein synthesis. The concomitant inhibition of RNA synthesis can adequately by explained by the stringent response phenomena. In a relaxed mutant strain (rel) of E. coli, protein synthesis is also inhibited, but the accumulation of RNA continues after the addition of the drug. Guanosine tetraphosphate (ppGpp), the putative mediator of the stringent control, accumulates in drug-treated stringently controlled E coli but not in the relaxed mutant. An additional direct effect of the drug on RNA synthesis can therefore be ruled out.

Measurements of polyamines and their acetylated derivatives in cell extracts and physiological fluids by use of an amino acid analyzer

A fast and sensitive method for the determination of free polyamines and their acetylated derivatives is presented. The separation is carried out on a Durrum DC-6A cation-exchange resin with an automated amino acid analyzer. The determination is based on a step wise elution with a sodium chloride-sodium citrate buffer system. Detection is done by fluorescence of the o-phthaldialdehyde-polyamine conjugates. The sensitivity is in the picomole range. No prior purification step is needed. The method has been applied to cell extracts and urine samples.

[How and when is immunotherapy for pollen allergy carried out?]

Hyposensitization with semi-depot extracts was effective in 164 of 201 (81,4%) grass pollen sensitive patients. In 54,1% the results were very good and good. Patients were treated perennially for two years. The success of treatment was evaluated by a questionnaire. The results show that treatment will be most effective if the disease has been of relative short duration, if patients are young, if the final dosage is high and a high total dosage is reached, and if side effects only occur as local reactions. The frequency of symptoms and their improvement are described.

[Mould allergy (author's transl)]

290 asthmatic patients with positive skin tests for mould allergens were analyzed retrospectively. The relationship between skin test and inhalative provocation test was investigated with regard to single allergens and polyvalent mould sensitivity. With 4 commercially available moulds the relationship between skin test, provocation test and RAST was investigated too. Alternaria alternata occupies a special position. Tests with Alternaria alternata, Aureobasidium pullulans, Penicillium notatum, Fusarium culmorum, Aspergilus fumigatus and Cladosporium herbarum showed the highest correlation correlation with clinical allergy. Allergic asthmatic patients are in about 10% sensitive for moulds. Penicillia tend to crossreaction; for other moulds no preferential combinations were found. Provocative inhalation tests have to be performed, if mould sensitivity is suspected. At present the results of RAST are mostly of no decisive diagnostic value.

Control of protein synthesis in mammalian cells by aminoacylation of transfer ribonucleic acid

The dependence of protein synthesis on the intracellular content of aminoacylated tRNA has been studied in mouse ascites tumor cells deprived for various amino acids. A remarkable reduction in net protein synthesis has been found only after a drastic decrease in aminoacylation of tRNA. The quantitative correlation of protein synthesis with the degree of aminoacylation suggests that a moderate amino acid starvation primarily influences the rate of elongation at the codon concerned. These results are in contrast to the findings previously reported for HeLa cells. Some crucial steps during the determination of intracellular aminoacyl-tRNA have been investigated. The reliability of the method employed has been discussed on a theoretical basis.

[Serum ribonuclease and its importance for renal diagnosis (author's transl)]

Ribonuclease activity in the serum is recommended in the literature for the diagnosis of tumors, especially carcinoma of the pancreas. On the other hand it has long been suspected that serum RNAase increases when renal function is reduced. It is shown that the RNAase activity in human serum correlates well the creatinine clearance. Tumor diseases are frequently coupled with reduced renal function which leads to a rise in RNAase. The serum RNAase activity is therefore only of limited application for tumor diagnosis. The rise in RNAase activity in the serum is, however, a useful measure for the reduced renal function. The analysis of serum RNAase could replace the determination of creatinine clearance.

[Hypersensitivity to antibiotics: Frequency, risks, cross-allergies (author's transl)]

The present paper gives a systematic review of the clinical manifestations of allergic reactions and the underlying immunological mechanisms. Attention is drawn to the relatively high proportion of cases of anaphylactic shock and serum disease related to the total number of cases of allergic reaction, and to the diagnostic techniques available for detection of sensitization towards antibiotics. Structural allergenicity is mentioned, using penicillin allergy as an example. The frequency of allergy to several antibiotics and the frequency of cross-reaction between penicillins and cephalosporins reported in the literature are discussed critically.

Nickel uptake by Flacourtiaceae of New Caledonia

Herbarium and field specimens (over 300) of all of the Flacourtiaceae of New Caledonia were analysed for nickel in order to identify hyperaccumulators (greater than 1000 microgram/g dry mass) and to assess nickel accumulation in relation to the evolutionary status of 'nickel plants' of New Caledonia. One hyperaccumulator was identified in the genus Lasiochlamys, ten among Xylosoma, one among Casearia and seven among Homalium. Although these Homalium nickel plants had previously been recorded, fresh data for these and other Homalium are presented. The remarkable tolerance of Flacourticeae to ultrabasic rocks is shown by the fact that 75% of the species are found on such substrates. The number of hyperaccumulators was greatest in the genera Xylosoma and Homalium. The Flacourtiaceae are among the most primitive of all angiosperms and in common with other primitive hyperaccumulators, contain nickel as a complex with citric acid. The only advanced New Caledonian nickel plant (Psychotria douarrei) has most of its nickel bound with ligands other than citric acid, a feature of other advanced hyperaccumulators. It is postulated that nickel complexing with citric acid may be a primitive character. Most of the New Caledonian nickel plants belong to the order Violales of subclass Dilleniidae. It is suggested that hyperaccumulation of nickel is an evolutionary character which occurs in long-indisturbed floras such as that of New Caledonia.

[Treatment of bronchitis with cefaclor (Panoral) (author's transl)]

14 patients from the Allergy Unit of an outpatient clinic suffering from acute exacerbation of chronic bronchitis and 13 outpatients with acute bronchitis were treated with 250 mg cefaclor (Panoral) 3 times daily per os for 5 days. 59% of the organisms isolated from cefaclor-sensitive sputum at the time of prominent clinical symptoms were resistent to tetracycline, 53% of them were resistant to penicillin, and 37% were resistant to ampicillin. 12 out of the 14 patients with acute exacerbation of chronic bronchitis became asymptomatic, and no organisms could be detected in the sputum of 13 out of the same 14 patients two days after cessation of cefaclor treatment. In 12 out of the 13 patients with acute bronchitis, the acute clinical symptoms disappeared and in 11 out of the 13 patients the initial sputum organisms were two days after stopping cefaclor treatment.

The molecular basis of leucine auxotrophy of quinone-treated Escherichia coli. Active site-directed modification of leucyl-tRNA synthetase by 6-amino-7-chloro-5,8-dioxoquinoline

Leucyl-tRNA synthetase from Escherichia coli is rapidly inactivated by 6-amino-7-chloro-5,8-dioxoquinoline (quinone), a model substance for cytostatic quinones. Loss of activity follows pseudo-first order kinetics. The quinone masks essential--SH groups that are reactive with N-ethylmaleimide. Specific protection of the enzyme by leucine provides evidence for active site-directed modification. Half-maximal protection is found at a concentration of 150 micron which is identical with the dissociation constant of the enzyme.substrate complex. The competitive inhibitor leucinol also protects the enzyme from inactivation by the quinone. MgATP enhances the protective effect of leucinol about 250-fold, thus substantiating recently published findings on synergistic coupling of ligands to aminoacyl-tRNA synthetases. The results support the assumption that the bacteriostatic quinone directly interferes with leucyl-tRNA synthetase in growing cells. Active-site-directed inhibition of the enzyme could adequately explain the phenotypically observed auxotrophy for leucine of quinone-treated E. coli.