[Chondrosarcoma of the hand arising from multiple enchondromas: a case report]. / Chondrosarkom an der Hand bei multiplen Enchondromen: ein Fallbericht.

Malignancy occurs more often in multiple enchondromas than in solitary enchondromas. In the hands the rate is about 14%. We amputated the third ray of the hand in a young man with recurrence of an enchondroma. The histology showed a low grade chondrosarcoma. The patient had no tumour recurrence or metastasis in the following 5 years. We describe the evaluation as well as the treatment and outline the literature.

Optical communications downlink from a low-earth orbiting 1.5U CubeSat.

In this article, we present the first demonstration of an optical communications downlink from a low-earth orbiting free-flying CubeSat. Two 1.5U vehicles, AC7-B&C, built under NASA's Optical Communications and Sensors Demonstration (OCSD) program were launched in November 2017 and subsequently placed into a 450-km, 51.6° inc. circular orbit. Pseudorandom data streams using on-off key (OOK) modulation were transmitted from AC-7B to a 40 cm aperture telescope located at sea level in El Segundo, CA. At 200 Mbps, without forward error correction (FEC), we achieved a 115-second link that was ~78% error free, with the remaining portion exhibiting an error rate below 1E-5. At the time of the engagement, the 1064-nm laser transmitter was operating at 2 W (half capacity) with a full width half maximum (FWHM) beam divergence of ~1 mrad, which was approximately double the anticipated pointing accuracy of the vehicle.

[Early surgical rehabilitation due to modified exenteration technique]. / Frühe chirurgische Rehabilitation durch modifizierte orbitale Exenteration.

BACKGROUND: Orbital exenteration is a life intruding surgical procedure with severe functional, aesthetic and psychological consequences. Apart from the correct tumor treatment, early aesthetic and psychosocial rehabilitation is crucial for the well-being of the patient. We discuss reasons leading to exenteration and present new surgical techniques. Local flaps in the anterior socket improve wound healing allowing early placement of the prosthesis and therefore faster social rehabilitation of the patient. PATIENTS AND METHODS: Between 2007 and 2011 seven patients with malignant orbital tumors (1 × plasmocytoma, 1 × melanoma, 1 × sarcoma, 1 × squamous cell carcinoma and 3 × basal cell carcinoma) received a radical orbital exenteration at the Department of Ophthalmology of the Zurich University Hospital. The medical histories were evaluated according to reasons for exenteration, surgical techniques and postoperative follow-up. Reconstruction of the anterior socket border succeeded using local flaps (Mustardé, Glabella and combined with further modified pedicled local full thickness skin flaps). The central defects were covered with split skin graft from the thigh. RESULTS: Three weeks after surgery the anterior border of the socket was completely healed without problems by local flaps with good blood supply. This allowed the early prosthetic fitting and wearing as well as quick social rehabilitation of the patient. CONCLUSIONS: The use of local flaps improves wound healing even in anticoagulated patients. This reduces the time of hospitalization and rehabilitation, and allows an early, satisfactory, social reintegration of the patient.

Isoprenoid biosynthesis in bacteria: two different pathways?

The biosynthesis of isopentenylpyrophosphate, a central intermediate of isoprenoid formation, was investigated in six different bacterial organisms. Cell-free extracts of Myxococcus fulvus, Staphylococcus carnosus, Lactobacillus plantarum and Halobacterium cutirubrum converted [14C]acetyl-CoA or [14C]hydroxymethylglutaryl-CoA to [14C]mevalonic acid. Furthermore, [14C]mevalonic acid, [14C]mevalonate-5-phosphate and [14C]mevalonate-5-pyrophosphate were metabolized to [14C]isopentenylpyrophosphate. These data demonstrated the in vitro operation of acetoacetate pathway for the formation of isopentenylpyrophosphate in bacteria. In contrast, no intermediates of this reaction sequence could be detected using cell-free extracts of Zymomonas mobilis and Escherichia coli. These results indicate that at least two different pathways for the biosynthesis of isopentenylpyrophosphate are present in bacteria.

Enzymatic synthesis of 6'-deoxychalcone in cultured Glycyrrhiza echinata cells.

5-Deoxy-(iso)flavonoids are biosynthesized from 6'-deoxychalcone (isoliquiritigenin). The coaction of a reductase with chalcone synthase (CHS) has been established in soybean cells to be responsible for the synthesis of 6'-deoxychalcone. Western blot analysis of crude extracts from cultured cells of Glycyrrhiza echinata, another member of the Leguminosae, revealed proteins which cross-react with an antiserum raised against the soybean reductase. DEAE-Cellulose chromatography of the extract yielded fractions which showed CHS activity but not deoxychalcone synthase activity, and these fractions were also negative in Western blot analysis. In contrast, fractions displaying positive signals with the antiserum were also able to synthesize 6'-deoxychalcone/5-deoxyflavanone. These results indicate that in G. echinata, too, synthesis of 6'-deoxychalcone is likely to be performed by the coaction of the reductase and CHS. Induction of the reductase and CHS by yeast extract treatment of the cells was demonstrated.

Expression cloning in Escherichia coli and preparative isolation of the reductase coacting with chalcone synthase during the key step in the biosynthesis of soybean phytoalexins.

The cDNA for the reductase involved in the biosynthesis of 6'-deoxychalcone (4,2',4'-trihydroxychalcone), the first specific intermediate in the pathway to soybean phytoalexins, was cloned into the expression vector pKK233-2 and transformed into Escherichia coli. Using this source, about 5 mg of homogeneous reductase was isolated from 45 g of cells. The protein purification protocol differs completely from the scheme applied to soybean cell cultures. Size, N-terminal and specific enzyme activities were identical for the plant and E. coli protein. The pure protein is fairly stable, retaining 70% of initial activity after storage at 5 degrees C during 4 weeks. This protein is used for crystallization and in the study of its protein-protein interaction with chalcone synthase.

Induced plant responses to pathogen attack. Analysis and heterologous expression of the key enzyme in the biosynthesis of phytoalexins in soybean (Glycine max L. Merr. cv. Harosoy 63).

In soybean (Glycine max L.), pathogen attack induces the formation of glyceollin-type phytoalexins. The biosynthetic key enzyme is a reductase which synthesizes 4,2', 4'-trihydroxychalcone in co-action with chalcone synthase. Screening of a soybean cDNA library from elicitor-induced RNA in lambda gt11 yielded two classes of reductase-specific clones. The deduced proteins match to 100% and 95%, respectively, with 229 amino acids sequenced in the purified plant protein. Four clones of class A were expressed in Escherichia coli, and the proteins were tested for enzyme activity in extracts supplemented with chalcone synthase. All were active in 4,2',4'-trihydroxychalcone formation, and the quantification showed that shorter lengths of the cDNAs at the 5' end correlated with progressively decreasing enzyme activities. Genomic blots with DNA from plants capable of 4,2',4'-trihydroxychalcone synthesis revealed related sequences in bean (Phaseolus vulgaris L.) and peanut (Arachis hypogaea L.), but not in pea (Pisum sativum L.). No hybridization was observed with parsley (Petroselinum crispum) and carrot (Daucus carota) which synthesize other phytoalexins. The reductase protein contains a leucine-zipper motif and reveals a marked similarity with other oxidoreductases most of which are involved in carbohydrate metabolism.

Intracellular localization of prenyltransferases of isoflavonoid phytoalexin biosynthesis in bean and soybean.

The intracellular localization of prenyltransferases involved in the biosynthesis of the phytoalexins glyceollin in soybean (Glycine max L.) and phaseollin in French bean (Phaseolus vulgaris L.) has been investigated. By sucrose- and Percoll-gradient centrifugation of microsomes of an elicitor-challenged soybean cell culture, the membranes containing prenyltransferase were separated from the endoplasmic reticulum and shown to be lighter in density. In a continuous Percoll gradient the peak of prenyltransferase activity coincided with the peak of galactolipid synthesis, as determined by incorporation of uridine 5'-diphospho-[(14)C]galactose (UDP-[(14)C]galactose). Intact chloroplasts isolated from cupricchloride-treated bean leaves contained both prenyltransferase and UDP-galactose transferase activity. Both activities increased during chloroplast isolation. Fractionation of swollen chloroplasts on a discontinuous sucrose gradient showed prenyltransferase and UDP-galactose transferase activity in the envelope membrane subfraction. It is concluded that in both plants prenyltransferase is located in the envelope membrane of plastids.

Phytoalexin synthesis in soybean cells: elicitor induction of reductase involved in biosynthesis of 6'-deoxychalcone.

Chromatofocusing on Mono P proved to be an efficient purification procedure for the NADPH-dependent reductase from soybean (Glycine max L.) cell cultures which acts together with chalcone synthase in the biosynthesis of 2',4',4-trihydroxychalcone (6'-deoxychalcone). By isoelectric focusing the pI of reductase was determined to be 6.3. Addition of pure soybean reductase to cell-free extracts from stimulated cell cultures of parsley and bean (Phaseolus vulgaris) and from young flowers of Dahlia variabilis caused in each case synthesis of 6'-deoxychalcone. When 4-coumaroyl-CoA was replaced by caffeoyl-CoA in the reductase assay, formation of 2',4',3,4-tetrahydrochalcone (butein) was observed. A polyclonal antireductase antiserum was raised in rabbits and proved to be specific in Ouchterlony diffusion experiments, Western blots and immunotitration. The reductase antiserum showed no cross-reactivity with soybean chalcone synthase (CHS). A biotin/[125I]streptavidin system provided a quantitative Western blot for the reductase. Changes in the activities, amounts of protein, and mRNA activities of reductase and CHS were determined after challenge of soybean cell cultures by elicitor (from Phytophthora megasperma f.sp. glycinea or yeast). For both enzymes a pronounced and parallel increase in activity and amounts of protein was observed after elicitor addition with a maximum at about 16 h after challenge. Parallel increases in mRNA activities occurred earlier. The results indicate a parallel induction of de novo synthesis of reductase and CHS which coact in synthesis of 6'-deoxychalcone.

Induction of phytoalexin synthesis in soybean: enzymatic cyclization of prenylated pterocarpans to glyceollin isomers.

A microsome preparation from elicitor-challenged soybean cell suspension cultures catalyzed an NADPH-dependent and oxygen-dependent cyclization of a mixture of 2- and 4-dimethylallylglycinols to the glyceollin isomers I-III. This is the last committed step in glyceollin biosynthesis. The cyclase was inhibited in a light-reversible manner by carbon monoxide in the presence of oxygen. Cyclase was also inhibited by cytochrome c, NADP+, and a number of inhibitors of cytochrome P-450 enzymes. NADH in the presence of low concentrations of NADPH had a synergistic effect. On a Percoll gradient, the position of cyclase coincided with marker enzymes for the endoplasmic reticulum. These properties identify the cyclase as a cytochrome P-450-dependent monooxygenase. Unstimulated soybean cell culture did not contain detectable cyclase activity. Challenge with either a glucan elicitor from Phytophthora megasperma f.sp. glycinea or with yeast extract caused strong stimulation of cyclase activity with a maximum at about 24 h after elicitor addition.

Differential induction of enzyme in soybean cell cultures by elicitor or osmotic stress.

Soybean cell cultures were challenged either by glucan elicitor from Phytophthora megasperma f.sp. glycinea or by osmotic stress (0.4 M glucose). Osmotic stress induced production of a microsomal NADPH-dependent flavone synthase (flavone synthase II) which catalyses conversion of (2S)-naringenin to apigenin. In one of our cell-lines this enzyme activity was not detected either in unchallenged cells or in cells treated with glucan elicitor. Inducibility of flavone synthase II by 0.4 M glucose was highest at the end of the linear growth phase. Changes in the activities of a number of other enzymes were determined after treatment of the cells with elicitor or 0.4 M glucose. The activities of phenylalanine ammonialyase, cinnamate 4-hydroxylase, chalcone synthase and dihydroxypterocarpan 6a-hydroxylase all increased with elicitor and with osmoticum, albeit to a different degree. The rise in enzyme activity occurred later with osmoticum than with elicitor. The prenyltransferase involved in glyceollin synthesis was induced strongly by elicitor but only very weakly by osmoticum, whereas isoflavone synthase and NADPH: cytochrome-c reductase were only induced by elicitor. The activity of glucose-6-phosphate dehydrogenase did not change with elicitor or with osmoticum. Different product patterns were also obtained: whereas with elicitor, glyceollin I was the major product, intermediates of the glyceollin pathway (7,4'-dihydroxyflavanone, trihydroxypterocarpan) accumulated with osmoticum.

The extraction constant of mercury(II) o-o'-dimethyldithizonate into toluene.

An attempt was made to determine spectrophotometrically the extraction constant of mercury(II) o-o'-dimethyldithizonate into toluene by means of a known excess of iodide as a masking agent. The results found, however, could not be explained by a simple reaction between mercury(II) o-o'-dimethyldithizonate and iodide.