Approaching boiling point stability of an alcohol dehydrogenase through computationally-guided enzyme engineering

Enzyme instability is an important limitation for the investigation and application of enzymes. Therefore, methods to rapidly and effectively improve enzyme stability are highly appealing. In this study we applied a computational method (FRESCO) to guide the engineering of an alcohol dehydrogenase. Of the 177 selected mutations, 25 mutations brought about a significant increase in apparent melting temperature (ΔTm ≥ +3 °C). By combining mutations, a 10-fold mutant was generated with a Tm of 94 °C (+51 °C relative to wild type), almost reaching water's boiling point, and the highest increase with FRESCO to date. The 10-fold mutant's structure was elucidated, which enabled the identification of an activity-impairing mutation. After reverting this mutation, the enzyme showed no loss in activity compared to wild type, while displaying a Tm of 88 °C (+45 °C relative to wild type). This work demonstrates the value of enzyme stabilization through computational library design.

Integrated Mechanical, Thermal, Data, and Power Transfer Interfaces for Future Space Robotics

In-situ connectability among modules of a space system can provide significantly enhanced flexibility, adaptability, and robustness for space exploration and servicing missions. Connection of modules in extra-terrestrial environment is hence a topic of rising importance in modern orbital or planetary missions. As an example, the increasing number of satellites sent to space have introduced a large set of connections of various type, for transferring mechanical loads, data, electrical power and heat from one module to another. This paper provides a comprehensive review of published work in space robotic connections and presents the different transfer types developed and used to date in robotic applications for orbital and extra-terrestrial planetary missions. The aims of this paper are to present a detailed analysis of the state of the art available technologies, to make an analysis of and comparison among different solutions to common problems, to synthesize and identify future connectability research, and to lay the foundation for future European space robotic connectability effort and work for a complex and growing important future space missions. All types are described in their base characteristics and evaluated for orbital and planetary environments. This analysis shows that despite the large number of connectors developed for each of the four functionalities (mechanical, thermal, data, and electrical power) here considered, the trend is that researchers are integrating more than one functionalizes into a single equipment or device, to reduce costs and improve standardization. The outcomes of this literature review have contributed toward the design of a future multifunctional, standard and scalable interface at the early stage of the Standard Interface for Robotic Manipulation of Payloads in Future Space Missions (SIROM) project, a European Commission funded Horizon 2020 project. SIROM interfaces will be employed by European prime contractors in future extra-terrestrial missions.

Three in One: Temperature, Solvent and Catalytic Stability by Engineering the Cofactor-Binding Element of Amine Transaminase

Amine transaminase (ATA) catalyse enantioselectively the direct amination of ketones, but insufficient stability during catalysis limits their industrial applicability. Recently, we revealed that ATAs suffer from substrate-induced inactivation mechanism involving dissociation of the enzyme-cofactor intermediate. Here, we report on engineering the cofactor-ring-binding element, which also shapes the active-site entrance. Only two point mutations in this motif improved temperature and catalytic stability in both biphasic media and organic solvent. Thermodynamic analysis revealed a higher melting point for the enzyme-cofactor intermediate. The high cofactor affinity eliminates the need for pyridoxal 5'-phosphate supply, thus making large-scale reactions more cost effective. This is the first report on stabilising a tetrameric ATA by mutating a single structural element. As this structural "hotspot" is a common feature of other transaminases it could serve as a general engineering target.

Enzymatic network for production of ether amines from alcohols

We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production of the desired ether amines from the corresponding ether alcohols with inorganic ammonium as the only additional substrate. To examine conversion, individual and overall reaction equilibria were established. Using these data, it was found that the experimentally observed conversions of up to 60% observed for reactions containing 10 mM alcohol and up to 280 mM ammonia corresponded well to predicted conversions. The results indicate that efficient amination can be driven by high concentrations of ammonia and may require improving enzyme robustness for scale-up. Biotechnol. Bioeng. 2016;113: 1853-1861. © 2016 Wiley Periodicals, Inc.

[Palpable arciforme migratory erythema]

A 39-year-old man presented with an annular clearly palpable erythema on the décolleté. Based on clinical and histopathological findings, palpable migratory arciform erythema was diagnosed. This skin condition is classified as a rare type of T-cell pseudolymphoma. It is still a matter of debate whether palpable migratory arciform erythema is a specific entity or a clinical variant of lymphocytic infiltration of the skin (Jessner-Kanof). Topical corticosteroids or oral antibiotics are generally used. In our patient, UV-A1 therapy led to a complete regression of the lesions.

Ironing out their differences: dissecting the structural determinants of a phenylalanine aminomutase and ammonia lyase

Deciphering the structural features that functionally separate ammonia lyases from aminomutases is of interest because it may allow for the engineering of more efficient aminomutases for the synthesis of unnatural amino acids (e.g., β-amino acids). However, this has proved to be a major challenge that involves understanding the factors that influence their activity and regioselectivity differences. Herein, we report evidence of a structural determinant that dictates the activity differences between a phenylalanine ammonia lyase (PAL) and aminomutase (PAM). An inner loop region that closes the active sites of both PAM and PAL was mutated within PAM (PAM residues 77-97) in a stepwise approach to study the effects when the equivalent residue(s) found in the PAL loop were introduced into the PAM loop. Almost all of the single loop mutations triggered a lyase phenotype in PAM. Experimental and computational evidence suggest that the induced lyase features result from inner loop mobility enhancements, which are possibly caused by a 310-helix cluster, flanking α-helices, and hydrophobic interactions. These findings pinpoint the inner loop as a structural determinant of the lyase and mutase activities of PAM.

Priming ammonia lyases and aminomutases for industrial and therapeutic applications

Ammonia lyases (AL) and aminomutases (AM) are emerging in green synthetic routes to chiral amines and an AL is being explored as an enzyme therapeutic for treating phenylketonuria and cancer. Although the restricted substrate range of the wild-type enzymes limits their widespread application, the non-reliance on external cofactors and direct functionalization of an olefinic bond make ammonia lyases attractive biocatalysts for use in the synthesis of natural and non-natural amino acids, including β-amino acids. The approach of combining structure-guided enzyme engineering with efficient mutant library screening has extended the synthetic scope of these enzymes in recent years and has resolved important mechanistic issues for AMs and ALs, including those containing the MIO (4-methylideneimidazole-5-one) internal cofactor.

Minimum 5-year results of focal articular prosthetic resurfacing for the treatment of full-thickness articular cartilage defects in the knee

INTRODUCTION

The purpose of this study was to evaluate the results of a contoured focal articular femoral condyle resurfacing prosthetic in the treatment of full-thickness cartilage and osteochondral defects at the medial femoral condyle of the knee beyond 5 years.

METHODS

In a multicenter case series, preoperative and follow-up scores of the Knee Injury and Osteoarthritis Outcome Score (KOOS), SF-36 and Tegner activity scale were evaluated. Standard radiographs were performed to evaluate the progression of osteoarthritis. Patients were also asked to report their satisfaction.

RESULTS

A total of 21 patients were included in this study. The average follow-up was 5.3 years. The average age at the time of resurfacing was 54 years. Average KOOS scores significantly (P ≤ 0.005) improved for pain (51.1 to 77.6), symptoms (57.9 to 79.5), activities of daily living (ADL) (58.8 to 82.4), sports (26.3 to 57.8) and quality of life (QOL) (34.4 to 55.0). The Tegner activity level improved significantly (P ≤ 0.02) from 2.9 to 4. The physical health value of the SF-36 increased by 15.2 to 46.9 compared to the preoperative value. The mental health value almost (51.2) remained unchanged. As many as 16/21 of the patients in this series were satisfied with their outcome and would have the operation again. Radiographic results demonstrated solid fixation, preservation of joint space and no change in the osteoarthritic stage.

CONCLUSIONS

The device appears to be an effective reconstructive treatment option for large full-thickness cartilage and osteochondral lesions of the knee in middle-aged patients.

The crystal structure of an esterase from the hyperthermophilic microorganism Pyrobaculum calidifontis VA1 explains its enantioselectivity

The highly thermostable esterase from the hyperthermophilic archaeon Pyrobaculum calidifontis VA1 (PestE) shows high enantioselectivity (E > 100) in the kinetic resolution of racemic chiral carboxylic acids, but little selectivity towards acetates of tertiary alcohols (E = 2-4). To explain these unique properties, its crystal structure has been determined at 2.0 Å resolution. The enzyme is a member of the hormone-sensitive lipase group (group H) of the esterase/lipase superfamily on the basis of the amino acid sequence identity. The PestE structure shows a canonical α/β-hydrolase fold as core domain with a cap structure at the C-terminal end of the β-sheet. A tetramer in the crystal packing is formed of two dimers; the dimeric form is observed in solution. Conserved dimers and even tetramers are found in other group H proteins. The amino acid residues Ser157, His284, and Asp254 form the catalytic triad, which is typically found in α/β-hydrolases. The oxyanion hole is composed of Gly85 and Gly86 within the conserved sequence motif HGGG(M,F,W) (amino acid residues 83-87) and Ala158. With the elucidated structure, experimental results about enantioselectivity towards the two model substrate classes (as exemplified for 3-phenylbutanoic acid ethyl ester and 1,1,1-trifluoro-2-phenylbut-3-yn-2-yl acetate) could be explained by molecular modeling. For both enantiomers of the tertiary alcohol, orientations in two binding pockets were obtained without significant energy differences corresponding to the observed low enantioselectivity due to missing steric repulsions. In contrast, for the carboxylic acid ester, two different orientations with significant energy differences for each enantiomer were found matching the high E values.

[Validation of continuous blood pressure measurements by pulse transit time: a comparison with invasive measurements in a cardiac intensive care unit]

BACKGROUND AND OBJECTIVE

Arterial blood pressure measured by pulse transit time (PTT) can be used as an alternative to the gold standard of invasive measurement. It was the aim of this study to compare these two methods in order to validate PTT in patients with cardiac diseases.

PATIENTS AND METHODS

In 40 patients (29 males; mean age 68.7 ± 15 years) in a cardiac intensive care unit, blood pressures were continuously measured by PTT and the standardized invasive method for one hour. Values were analysed and compared in 30-second intervals (9,600 values for each method).

RESULTS

Blood pressures obtained with either method were not statistically different, neither in the whole group nor in subgroups. However, the number of analysable data was significantly higher using the invasive method, by which appropriate signals were obtained in 99.2 % of systolic and in 99.1 % of diastolic blood pressure measurements. In contrast, using the PTT-method, appropriate signals were seen in 85.8 % of systolic and 85.9 % of diastolic pressure measurements.

CONCLUSION

Blood pressures measured by PTT in patients in cardiac intensive care units provide reliable values over a period of at least one hour. However, the PTT method seems to be more susceptible to errors as evidenced by the number of failed measurements.

Mutational analysis of phenylalanine ammonia lyase to improve reactions rates for various substrates

Phenylalanine ammonia lyases (PAL) catalyze the reversible, non-reductive amination of trans-cinnamic acid to l-phenylalanine in the presence of high ammonia concentrations. Since neither cofactor recycling nor other additives are needed and by this asymmetric synthesis theoretical yields of 100% can be reached, it is an interesting reaction for industrial processes. In this study we demonstrate the superior properties of p-nitro-cinnamic acid (p-n-CA) in the amination reaction using the PAL from Petroselinum crispum (pcPAL). By focused-directed evolution, three mutants were identified showing increased reaction rates and decreased substrate inhibition. Together, the F137V mutant with p-n-CA showed a 15-fold increased reaction rate compared with the pcPAL WT with the natural cinnamic acid. The high reaction rates were also proven in preparative scale experiments. Activities towards other p-substituted cinnamic acids showing different electronic effects of the substituent were analyzed. Focused-directed evolution around the carboxylic acid- and amine-binding site always decreased PAL activity, due to a sensitive H-bond network.

Comparative Multi-Epitope-Ligand-Cartography reveals essential immunological alterations in Barrett's metaplasia and esophageal adenocarcinoma

Background

Barrett's esophagus (BE) is caused by gastroesophageal reflux with consecutive mucosal inflammation, predisposing patients to the development of esophageal adenocarcinoma (EAC). We investigated changes in T cell-related mucosal combinatorial molecular protein patterns in both diseases using the novel Multi-Epitope-Ligand-Cartography, a unique robotic whole-cell imaging technology that simultaneously visualizes dozens of proteins in structurally intact tissues and correlates cellular localization of proteins with function.

Results

Biopsies were taken during endoscopy from BE, EAC, and normal control tissue, and proteomic microscopy was performed on 32 different epitopes. When the significance level was set to p < 0.0005 and the search depth to five antibody combinations, controls and BE can be differentiated by 63, controls and EAC by 3222, and BE from EAC by 1521 distinct protein combinations.

For example, the number of activated apoptotic naïve and memory T cells was significantly increased only in BE, whereas the number of activated apoptotic helper and regulatory T cells was significantly elevated in BE and EAC. In contrast, the number of activated apoptotic cytotoxic T cells was significantly elevated only in EAC. Confirming different pathways in BE and EAC, the number of T lymphocytes with p53 expression and downregulation of bcl2 expression (CD3⁺p53⁺Bcl2^-NfkB^-) was significantly increased in EAC compared to BE and controls. Interestingly, the number of precursor T cells (CD7⁺) was significantly elevated only in EAC. These cells lack Bax and caspase-8, suggesting impaired apoptosis in the early stages of T cell differentiation.

Conclusion

Proteomic analysis showed for the first time that proteins, which are critically involved in the mucosal immune system of the esophagus, are distinctly expressed in BE and EAC, whereas others are comparably altered in both diseases, suggesting that many pathogenic events might be shared by both diseases. Topological proteomic analysis, therefore, helps us to understand the different pathogenic events in the underlying disease pathways.

A single residue influences the reaction mechanism of ammonia lyases and mutases

All ways lead to Rome? Computer modeling and kinetic measurements identified a distinct residue in Phe/Tyr ammonia lyases (PAL/TAL) which controls whether the Friedel-Crafts or an E(1)cB reaction mechanism takes place. Hence, Glu484 in pcPAL favors the Friedel-Crafts reaction (see picture, MIO = 4-methylidene imidazol-5-one) whereas an Asn in TAL gives an elimination reaction. These mechanistic investigations also reveal activity of a PAL mutant and a TAL towards an amino alcohol.

Systematic high-content proteomic analysis reveals substantial immunologic changes in colorectal cancer

The immune system is a significant determinant of epithelial tumorigenesis, but its role in colorectal cancer pathogenesis is not well understood. The function of the immune system depends upon the integrity of the protein network environment, and thus, we performed MELC immunofluorescence microscopy focusing on the lamina propria. By analyzing structurally intact tissues from colorectal cancer, ulcerative colitis, and healthy colonic mucosa, we used this unique and novel highly multiplexed robotic-imaging technology, which allows visualizing dozens of proteins simultaneously, and explored the toponome in colorectal cancer mucosa for the first time. We identified 1,930 motifs that distinguish control from colorectal cancer tissue. In colorectal cancer, the number of activated T cells is increased, explained by a lack of bax, caspase-3, and caspase-8. Whereas CD4(+)CD25(+) T cells are decreased and are, other than in ulcerative colitis, not activated, cytotoxic T cells are significantly increased in colorectal cancer. Furthermore, the number of activated human lymphocyte antigen (HLA)-DR(+) T-cells is increased in colorectal cancer, pointing to an altered antigen presentation. In colorectal cancer, CD3(+)CD29(+) expression and assembly of the LFA-1 and LFA-3 receptor are differentially changed, indicating a distinct regulation of T-cell adhesion in colorectal cancer. We also identified increased numbers of natural killer and CD44(+) cells in the colorectal cancer mucosa and nuclear factor-kappaB as regulator of apoptosis in these cell populations. High-content proteomic analysis showed that colorectal cancer induces a tremendous modification of protein expression profiles in the lamina propria. Thus, topological proteomic analysis may help to unravel the role of the adaptive immune system in colorectal cancer and aid the development of new antitumor immunotherapy approaches.

Proteomic analysis of the inflamed intestinal mucosa reveals distinctive immune response profiles in Crohn's disease and ulcerative colitis

Although Crohn's disease (CrD) and ulcerative colitis (UC) share several clinical features, the mechanisms of tissue injury differ. Because the global cellular function depends upon the protein network environment as a whole, we explored changes in the distribution and association of mucosal proteins to define key events involved in disease pathogenesis. Endoscopic biopsies were taken from CrD, UC, and control colonic mucosa, and Multi-Epitope-Ligand-Cartographie immunofluorescence microscopy with 32 different Abs was performed. Multi-Epitope-Ligand-Cartographie is a novel, highly multiplexed robotic imaging technology which allows integrating cell biology and biomathematical tools to visualize dozens of proteins simultaneously in a structurally intact cell or tissue. In CrD, the number of CD3+CD45RA+ naive T cells was markedly increased, but only activated memory, but not naive, T cells expressed decreased levels of Bax, active caspase-3 or -8. In UC, only CD4+ T cells coexpressing NF-kappaB were caspase-8 and poly(ADP-ribose)-polymerase positive. Furthermore, the number of CD4+CD25+ T cells was elevated only in UC, whereas in CrD and controls, the number of these cells was similar. By using hub analysis, we also identified that the colocalization pattern with NF-kappaB+ and poly(ADP-ribose)-polymerase+ as base motifs distinguished CrD from UC. High-content proteomic analysis of the intestinal mucosa demonstrated for the first time that different T cell populations within the intestinal mucosa express proteins translating distinct biological functions in each form of inflammatory bowel disease. Thus, topological proteomic analysis may help to unravel the pathogenesis of inflammatory bowel disease by defining distinct immunopathogenic profiles in CrD and UC.

Profiling lymphocyte subpopulations in peripheral blood under efalizumab treatment of psoriasis by multi epitope ligand cartography (MELC) robot microscopy

CD11a-blocking efalizumab has recently been approved as a systemic treatment of moderate to severe chronic plaque psoriasis. When treating 6 psoriasis patients with efalizumab over 12 weeks in the present study, we observed an overall good tolerability and 5 treatment responders characterized by a decrease of PASI from 21.3 +/- 5.4 to 3.9 +/- 0.6. The accompanying significant increase of peripheral blood lymphocytes from 1.9 +/- 0.7 to 4.3 +/- 1.0 x 10(9)/L (p < 0.05) was analyzed by multi epitope ligand cartography (MELC) robot microscopy. Thereby a high-dimension simultaneous multiplex immunophenotyping was pursued using 39 fluorophore-labeled antibodies including labeled efalizumab and 3 other affinity reagents such as lectins. Due to efalizumab treatment there was a substantial decrease of the cellular expression of CD11a (detected by mab clone 25.3.1) and efalizumab binding sites (EfaBSs). This was paralleled by an increase of the number of EfaBS- and EfaBS+ lymphocytes by a factor of 2.4x and 2.2x, respectively. The latter effect was mainly derived from a subpopulation showing a low degree of EfaBS expression. Efalizumab treatment led furthermore to an increase of the numbers of CD3+, CD4+, CD8+, CD44+, CD45+, CD45R0+, CD45 RA+, CD52+, CD58+, CD247+, HLA-DR+ and Sambucus nigra lectin-reactive lymphocytes (by factors from 2.0 to 3.3x). In terms of a combinatorial molecular phenotype we identified a CD3+/CD4+/CD44+/CD52+ lymphocyte subpopulation which accumulated most predominantly from 0.824 +/- 0.270 x 10(9)/L up to 1.616 +/- 0.152 x 10(9)/L under efalizumab treatment (p < 0.01). Thus, the current study extends the knowledge of efalizumab-dependent perturbations of recirculating blood lymphocyte subpopulations in psoriasis patients.

Regional and cellular distribution of the extracellular matrix protein tenascin-C in the chick forebrain and its role in neonatal learning

The juvenile brain's pronounced synaptic plasticity in response to early experience and learning events is related to the fact that the genetically pre-programmed molecular machinery mediating neuronal development and synapse formation, is activated throughout postnatal brain development and thereby can be recruited for learning and long-term memory formation. In situ hybridization and immunocytochemistry experiments revealed that tenascin-C, one candidate molecule which we suspect to be involved in neonatal learning, is expressed in the forebrain of domestic chicks around the sensitive period during which auditory filial imprinting takes place. The involvement of tenascin-C in this juvenile learning task was tested by injections of monoclonal antibodies directed to distinct domains of the tenascin-C molecule into the avian prefrontal cortex analog, the medio-rostral nidopallium/mesopallium (formerly termed medio-rostral neostriatum/hyperstriatum ventrale), a forebrain area which has been shown to be critically involved in auditory filial imprinting. Injections of monoclonal antibody Tn 68, which is directed against a cell-binding domain of the tenascin-C molecule, strongly reduced the imprinting rate, as opposed to injections of the monoclonal antibody Tn 578, which binds to a domain involved in neurite outgrowth. Double labeling immunohistochemistry revealed that tenascin-C is associated with neurons which express the Ca(2+)-binding protein parvalbumin, and displays a staining pattern highly reminiscent of perineuronal nets of the extracellular matrix. These results indicate that a distinct domain of tenascin-C is functionally involved in the juvenile learning process of filial imprinting and further suggest a critical role of a specific neuronal subpopulation.

Haemodynamic effects of dopexamine on postprandial splanchnic hyperaemia

BACKGROUND

The synthetic beta(2)-adrenergic and dopaminergic agonist dopexamine is supposed to prevent splanchnic hypoperfusion in critically ill patients, thus potentially interacting with haemodynamic effects of early enteral nutrition. However, precise mechanism of action and interaction with postprandial splanchnic hyperaemia of the drug are largely unknown, even in healthy subjects.

MATERIALS AND METHODS

Twelve healthy volunteers received dopexamine 1 microg x kg(-1) min(-1) and dopexamine and placebo (NaCl 0.9%) 3 microg x kg(-1) min(-1) in a randomized, double-blinded order (crossover-design). Splanchnic (Doppler ultrasound) and systemic (noninvasive cardiac monitoring) haemodynamic parameters were assessed at baseline and during infusion (fasted as well as 15, 30, 45 and 60 min after a standard liquid meal).

RESULTS

In fasted humans, dopexamine enhanced time-averaged maximum velocity (TAMX) in the superior mesenteric artery (1 microg + 40%; 3 microg + 82%, P < 0.05), portal vein (+ 63%; + 121%, P < 0.05) and femoral artery (+ 66%; + 87%, P < 0.05), in proportion to the increase of cardiac index (+ 33%; + 77%, both P < 0.05). In the postprandial state, TAMX rose significantly in the superior mesenteric artery (+ 139%) and portal vein (+ 68%) in the placebo group, showing the same absolute extent as dopexamine. The physiological postprandial buffer response of hepatic artery was conserved under all conditions.

CONCLUSIONS

Continuous infusion of dopexamine enhances mesenterial and portal perfusion in a dose-dependent manner without affecting the extent of physiological postprandial hyperaemia. Thus, dopexamine and enteral nutrition may interact with splanchnic haemodynamics by different pathways.

Cadherin expression pattern in melanocytic tumors more likely depends on the melanocyte environment than on tumor cell progression

BACKGROUND

Adhesion molecules have been assigned an important role in melanocytic tumor progression. By the loss of E-cadherin, melanocytes might escape the control of neighbouring keratinocytes. Although in vitro data support this hypothesis, there are yet no conclusive immunohistochemical results on cadherin expression in melanocytic tumors.

OBJECTIVE

To gain detailed insight in the expression of cadherins and their cytoplasmic binding partners, the catenins, in various types of benign and malignant melanocytic neoplasms.

METHODS

Immunohistochemical analysis of the expression of E-, P-, and N-cadherin and alpha-, beta-, and gamma-catenin in compound and dermal nevi, Spitz nevi, blue nevi, ultraviolet B (UVB)-irradiated nevi, and malignant melanomas of various tumor thickness.

RESULTS

In both nevi and melanomas, E-cadherin expression in melanocytic cells decreased, following a gradient from junctional to deeper dermal localization. The pattern of E-cadherin expression was more heterogeneous in melanomas than in nevi. In some melanomas, E-cadherin was only weakly positive in the epidermal tumor cells. P-cadherin expression was similar to that of E-cadherin. N-cadherin expression in melanocytic lesions was a rare finding, however, a small percentage of melanomas showed expression in some cell nests. Some Spitz nevi exhibited strong N-cadherin immunoreactivity. Most melanocytic cells were alpha- and beta-catenin-positive and gamma-catenin-negative. UVB irradiation did not influence the expression of cadherins and catenins in melanocytic nevi in vivo.

CONCLUSIONS

It is presumed that the gradual loss of E-cadherin expression represents a reaction of melanocytic cells to altered conditions in the dermal environment, e.g. lack of contact to keratinocytes, or new contact with dermal extracellular matrix molecules, respectively. Melanoma cells apparently are less dependent on these environmental factors and, therefore, show a more heterogeneous expression pattern. This might be of importance for the adaptation of the tumor cells to local requirements. However, in view of our results, a causative role of (loss of ) E-cadherin or (gain of ) N-cadherin for melanocytic tumor progression still remains to be proven.

Winkelstabile, volare Plattenosteosynthese komplexer artikul�rer Frakturen am distalen Radius

Fractures of the distal radius represent one of the most common fractures and have high socioeconomic relevance. Using the volar approach to avoid the soft tissue problems associated with dorsal plating, we treated a consecutive series of 49 displaced intra-articular distal radius fractures with a new fixed-angle internal fixation device. According to the AO classification, there were 21 C1, 19 C2, and nine C3 fractures. A retrospective study was carried out to obtain the functional results after open reduction and plate osteosynthesis. Loss of correction between postoperative and follow-up radiography was 1 degrees in volar tilt and radial inclination. The radial shortening was 1 mm. Wrist motion at final follow-up examination had recovered to an average of 80% of that at the normal, contralateral site. Overall outcome according to the Gartland and Werley scales showed 35% excellent, 50% good, and 15% fair results. Using the Martini score, we obtained 85% excellent and good results. The DASH score represented high subjective satisfaction.

Lack of toxic side effects in neutrophils following hyperbaric oxygen

Conflicting data have been reported about the impact of repeated HBO2 exposure on the production of superoxide radicals during the neutrophil respiratory burst (RB) and on phagocytosis. In this study we wanted to see if exposure to hyperoxia would affect human neutrophil RB and phagocytosis. Short- and long-term effects after single or repetitive HBO2 exposure of 2.5 atmospheres absolute over a period of 90 min were studied in 40 healthy volunteers. The RB was measured by the intracellular oxidation of dihydrorhodamine after induction by Escherichia coli (E. coli), or priming with recombinant tumour necrosis factor alpha (TNF-alpha), followed by N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation. The phagocytic activity was determined by the intake of FITC-labelled opsonized E. coli. No differences could be found between RB and phagocytic activity before and after HBO2 therapy, regardless of short- or long-term exposure. These findings indicate that exposure to hyperoxia does not impair these two important functions of the human innate host defense.

The human neutrophil lipocalin supports the allosteric activation of matrix metalloproteinases

The human neutrophil lipocalin (HNL), a member of the large family of lipocalins that exhibit various physiological functions, is coexpressed in granulocytes with progelatinase B (MMP-9). Part of it is covalently bound to the proenzyme and therefore may play a possible role in the activation process of promatrix metalloproteinases. We now report that HNL is able to accelerate the direct activation of promatrix metalloproteinases slightly. A significant enhancement of the activity could be demonstrated for the HgCl2- and the plasma kallikrein-induced activation of all three secretory forms of proMMP-9 and of proMMP-8. The same activating effects were exerted by HNL isolated from granulocytes as well as by the recombinant forms expressed by the yeast Pichia pastoris or by Escherichia coli. This demonstrates that the carbohydrate moiety is not essential for the biological activity of HNL. Activation and activity enhancement are obviously mediated by entrapping the remaining N-terminal sequence residues of the partially truncated proenzyme into the hydrophobic binding pocket of the HNL. In conclusion these results document that HNL can exert an enzyme-activating effect in the regulation of inflammatory and pathophysiological responses of granulocytes in the physiological activation of MMPs that have been subject to limited proteolytic processing.

Severe hypomyelination of the murine CNS in the absence of myelin-associated glycoprotein and fyn tyrosine kinase

The analysis of mice deficient in the myelin-associated glycoprotein (MAG) or Fyn, a nonreceptor-type tyrosine kinase proposed to act as a signaling molecule downstream of MAG, has revealed that both molecules are involved in the initiation of myelination. To obtain more insights into the role of the MAG-Fyn signaling pathway during initiation of myelination and formation of morphologically intact myelin sheaths, we have analyzed optic nerves of MAG-, Fyn- and MAG/Fyn-deficient mice. We observed a slight hypomyelination in optic nerves of MAG mutants that was significantly increased in Fyn mutants and massive in MAG/Fyn double mutants. The severe morphological phenotype of MAG/Fyn mutants, accompanied by behavioral deficits, substantiates the importance of both molecules for the initiation of myelination. The different severity of the phenotype of different genotypes indicates that the MAG-Fyn signaling pathway is complex and suggests the presence of compensatory mechanisms in the single mutants. However, data are also compatible with the possibility that MAG and Fyn act independently to initiate myelination. Hypomyelination of optic nerves was not related to a loss of oligodendrocytes, indicating that the phenotype results from impaired interactions between oligodendrocyte processes and axons and/or impaired morphological maturation of oligodendrocytes. Finally, we demonstrate that Fyn, unlike MAG, is not involved in the formation of ultrastructurally intact myelin sheaths.

Long-term follow-up results of irradiation alone or combined with surgery in stage I-IV carcinoma of the uterine cervix

OBJECTIVE

Evaluation of side effects and prognostic factors for survival in cervical carcinoma treated with radiation therapy +/- surgery.

MATERIAL AND METHODS

From January 1986 to June 1995 277 female patients with cervical carcinoma were treated by irradiation in the Department of Radiation Oncology of the University of Münster. Out of them 224 patients were evaluable for clinical features. 20 of them did not undergo complete radiation series and 14 patients received irradiation for recurrent disease, therefore 190 patients (n = 103 pts. with primary irradiation, n = 87 pts. with postoperative irradiation) were analyzed for survival/therapeutic features.

RESULTS

5-year-disease-free survival rates after primary irradiation: (FIGO I number of patients too small); FIGO II (n = 33 pts.) 52%; FIGO III (n = 44 pts.) 39.5%; FIGO IV (n = 18 pts.) 26%. 5-year-survival rates after postoperative irradiation: pT1 (n = 43 pts.) 87.4%; pT2 (n = 37 pts.) 47%. As significant prognostic factors for disease specific survival after irradiation alone the hemoglobin bloodlevel at the beginning of radiation therapy, tumor stage according to FIGO, tumor size and irradiation of the paraaortic region were revealed. As significant prognostic factors for disease free survival after postoperative irradiation were seen: interval between surgery and the beginning of radiation therapy, tumor invasion of parametria, postoperative stage, involvement of lymph nodes and lymph-/hemangiosis. The documented side effects among all patients corresponded to data found in literature.

CONCLUSIONS

Prognostic factors for disease free survival in our patients corresponded to the results of other studies. Acute and chronic side effects after irradiation were within the usual range. Especially in case of additional irradiation of the paraaortic region we could not find an accumulation of side effects. An elevation of disease free survival rates in patients with cervical carcinoma probably could be obtained by improving positional techniques for irradiation or changing fractionation schedules.

The solution structure and dynamics of human neutrophil gelatinase-associated lipocalin

Human neutrophil gelatinase-associated lipocalin (HNGAL) is a member of the lipocalin family of extracellular proteins that function as transporters of small, hydrophobic molecules. HNGAL, a component of human blood granulocytes, binds bacterially derived formyl peptides that act as chemotactic agents and induce leukocyte granule discharge. HNGAL also forms a complex with the proenzyme form of matrix metalloproteinase-9 (pro-MMP-9, or progelatinase B) via an intermolecular disulphide bridge. This association allows the subsequent formation of ternary and quaternary metalloproteinase/inhibitor complexes that vary greatly in their metalloproteinase activities. The structure and dynamics of apo-HNGAL have been determined by NMR spectroscopy. Simulated annealing calculations yielded a set of 20 convergent structures with an average backbone RMSD from mean coordinate positions of 0. 79(+/-0.13) A over secondary structure elements. The overall rotational correlation time (13.3 ns) derived from15N relaxation data is consistent with a monomeric protein of the size of HNGAL (179 residues) under the experimental conditions (1.4 mM protein, pH 6.0, 24.5 degrees C). The structure features an eight-stranded antiparallel beta-barrel, typical of the lipocalin family. One end of the barrel is open, providing access to the binding site within the barrel cavity, while the other is closed by a short 310-helix. The free cysteine residue required for association with pro-MMP-9 lies in an inter-strand loop at the closed end of the barrel. The structure provides a detailed model of the ligand-binding site and has led to the proposal of a site for pro-MMP-9 association. Dynamic data correlate well with structural features, which has allowed us to investigate a mechanism by which a cell-surface receptor might distinguish between apo and holo-HNGAL through conformational changes at the open end of the barrel.