Hemoglobin senses body temperature

When aspirating human red blood cells (RBCs) into 1.3 μm pipettes (ΔP = −2.3 kPa), a transition from blocking the pipette below a critical temperature T _c = 36.3 ± 0.3°C to passing it above the T _c occurred (micropipette passage transition). With a 1.1 μm pipette no passage was seen which enabled RBC volume measurements also above T _c. With increasing temperature RBCs lost volume significantly faster below than above a T _c = 36.4 ± 0.7 (volume transition). Colloid osmotic pressure (COP) measurements of RBCs in autologous plasma (25°C ≤ T ≤ 39.5°C) showed a T _c at 37.1 ± 0.2°C above which the COP rapidly decreased (COP transition). In NMR T₁-relaxation time measurements, the T₁ of RBCs in autologous plasma changed from a linear (r = 0.99) increment below T _c = 37 ± 1°C at a rate of 0.023 s/K into zero slope above T _c (RBC T₁ transition). In conclusion: An amorphous hemoglobin–water gel formed in the spherical trail, the residual partial sphere of the aspirated RBC. At T _c, a sudden fluidization of the gel occurs. All changes mentioned above happen at a distinct T _c close to body temperature. The T _c is moved +0.8°C to higher temperatures when a D₂O buffer is used. We suggest a mechanism similar to a “glass transition” or a “colloidal phase transition”. At T _c, the stabilizing Hb bound water molecules reach a threshold number enabling a partial Hb unfolding. Thus, Hb senses body temperature which must be inscribed in the primary structure of hemoglobin and possibly other proteins. This article is dedicated to Ludwig Artmann who died on July 21, 2001 on a beautiful summer day during which we performed experiments far away. Ludwig Artmann was a man who encouraged us to be strong and to study hard no matter what were the costs.     

Isolation, Characterisation and Molecular Imaging of a High-Molecular-Weight Insect Biliprotein, a Member of the Hexameric Arylphorin Protein Family

The abundant blue hemolymph protein of the last instar larvae of the moth Cerura vinula was purified and characterized by protein-analytical, spectroscopic and electron microscopic methods. Amino acid sequences obtained from a large number of cleavage peptides revealed a high level of similarity of the blue protein with arylphorins from a number of other moth species. In particular, there is a high abundance of the aromatic amino acids tyrosine and phenylalanine amounting to about 19% of total amino acids and a low content of methionine (0.8%) in the Cerura protein. The mass of the native protein complex was studied by size-exclusion chromatography, analytical ultracentrifugation, dynamic light scattering and scanning transmission electron microscopy and found to be around 500 kDa. Denaturating gel electrophoresis and mass spectrometry suggested the presence of two proteins with masses of about 85 kDa. The native Cerura protein is, therefore, a hexameric complex of two different subunits of similar size, as is known for arylphorins. The protein was further characterized as a weakly acidic (pI ∼ 5.5) glycoprotein containing mannose, glucose and N-acetylglucosamine in an approximate ratio of 10:1:1. The structure proposed for the most abundant oligosaccharide of the Cerura arylphorin was the same as already identified in arylphorins from other moths. The intense blue colour of the Cerura protein is due to non-covalent association with a bilin of novel structure at an estimated protein subunit-to-ligand ratio of 3:1. Transmission electron microscopy of the biliprotein showed single particles of cylindrical shape measuring about 13 nm in diameter and 9 nm in height. A small fraction of particles of the same diameter but half the height was likely a trimeric arylphorin dissociation intermediate. Preliminary three-dimensional reconstruction based on averaged transmission electron microscopy projections of the individual particles revealed a double-trimeric structure for the hexameric Cerura biliprotein complex, suggesting it to be a dimer of trimers.     

Dissemination of Escherichia coli with CTX-M Type ESBL between Humans and Yellow-Legged Gulls in the South of France

Extended Spectrum β-Lactamase (ESBL) producing Enterobacteriaceae started to appear in the 1980s, and have since emerged as some of the most significant hospital-acquired infections with Escherichia coli and Klebsiella being main players. More than 100 different ESBL types have been described, the most widespread being the CTX-M β-lactamase enzymes (bla _CTX-M genes). This study focuses on the zoonotic dissemination of ESBL bacteria, mainly CTX-M type, in the southern coastal region of France. We found that the level of general antibiotic resistance in single randomly selected E. coli isolates from wild Yellow-legged Gulls in France was high. Nearly half the isolates (47,1%) carried resistance to one or more antibiotics (in a panel of six antibiotics), and resistance to tetracycline, ampicillin and streptomycin was most widespread. In an ESBL selective screen, 9,4% of the gulls carried ESBL producing bacteria and notably, 6% of the gulls carried bacteria harboring CTX-M-1 group of ESBL enzymes, a recently introduced and yet the most common clinical CTX-M group in France. Multi locus sequence type and phylogenetic group designations were established for the ESBL isolates, revealing that birds and humans share E. coli populations. Several ESBL producing E. coli isolated from birds were identical to or clustered with isolates with human origin. Hence, wild birds pick up E. coli of human origin, and with human resistance traits, and may accordingly also act as an environmental reservoir and melting pot of bacterial resistance with a potential to re-infect human populations.     

CD‐sensitive Zn‐porphyrin tweezer host‐guest complexes,part 2: Cis‐ and trans‐3‐hydroxy‐4‐aryl/alkyl‐β‐lactams. A case study

This article describes an application of the host‐guest chiral recognition approach called tweezer methodology for the determination of the absolute configuration of 3‐hydroxy‐β‐lactams. These substrates represent challenging cases due to their chemical reactivity, the presence of multiple stereogenic centers and several functional groups which offer various possibilities of binding to the Zn‐porphyrin host. OPLS‐2005, the force field used in this work to predict the interporphyrin twist, modeled correctly the host‐guest complexation mechanism and revealed conformational details of the bound substrates. The computational study also suggested that in cases where an increase in the magnitude of the stereodifferentiation and an intense experimental CD are observed, the bound conformation of the conjugates are hydrogen bonded. The present investigation provides evidence that when the tweezer method is assisted by the OPLS‐2005 based computational approach, it can be successfully applied to the configurational and conformational elucidation of multi‐functional compounds with multiple stereogenic centers. Chirality, 2010. © 2009 Wiley‐Liss, Inc.     

Exploration of the use of an acylsulfonamide safety-catch linker for the polymer-supported synthesis of hyaluronic acid oligosaccharides

The synthesis of hyaluronic acid oligosaccharides on polyethylene glycol (PEG) using an acylsulfonamide linker has been explored. Hyaluronic acid is a challenging synthetic target that usually involves the condensation of highly disarmed glucuronic acid building blocks. Amine-ended PEG monomethyl ether was efficiently functionalized with a hydroxyl-terminated acylsulfonamide linker. Suitably protected d-glucosamine (GlcN) and d-glucuronic acid (GlcA) monosaccharide building blocks were coupled to the polymer acceptor using the trichloroacetimidate glycosylation method. The sulfonamide safety-catch linker enables simultaneous cleavage of the monosaccharide from the polymer and orthogonal functionalization for further (bio)-conjugation of the sugar sample. Subsequent glycosylation of PEG-bound glycosyl acceptor to generate hyaluronic acid oligosaccharide chain failed. Model glycosylation experiments in solution and on soluble support using the same unreactive acceptors and donors allows for the synthesis of an orthogonally protected hyaluronic acid disaccharide and suggest that the encountered difficulties could be attributed to the presence of the N-acylsulfonamide.     

Comparison of laser Doppler imaging, fingertip lacticemy test, and nailfold capillaroscopy for assessment of digital microcirculation in systemic sclerosis

Introduction  

Laser Doppler imaging (LDI) is a relatively new method for assessing the functional aspect of superficial skin blood flow in systemic sclerosis (SSc) and Raynaud's phenomenon. The present study investigated the dynamic behavior of digital skin microvascular blood flow before and after cold stimulus (CS) in SSc patients and in healthy controls by means of a comprehensive approach of the functional (LDI), morphological (nailfold capillaroscopy (NFC)), and biochemical (fingertip lacticemy (FTL)) microcirculation components.     

Mesothelioma and asbestosis in a young woman following occupational asbestos exposure: Short latency and long survival: Case Report

Background

Occult neoplastic cells (ONCs) are the tumor cells floating in the lymph node sinuses, distant from the primary tumor, and supposed to be one of most reliable marker of prognosis.

Methods

We report here the case of a 52-year-old woman with a gastric cancer associated by numerous ONCs.

Results

Postoperative examination of the stomach disclosed an advanced, poorly differentiated adenocarcinoma with frequent lymph node metastases. In addition to ONCs and occasional micrometastases, focal aggregates of ONCs, one of the possible intermediate lesions between the ONCs and the usual metastases, are also observed.

Conclusions

In the present case, at least some of ONCs seem to form the microaggregates of tumor cells in lymph nodes, anchor in the sinuses, and grow up to the large tumorous lesion. Even if most of the ONCs were trapped and disappeared under the influence of tumor immunity, the detection of ONCs could be one of the reliable clues to estimate the prognosis.     

Irreversible active-site-directed inhibition of Δ5-3-ketosteroid isomerase by steroidal 17-β-oxiranes. Evidence for two modes of binding in steroid-enzyme complexes

The spiro-17β-oxiranyl derivatives of d-equilenin, epiandrosterone, dehydroepiandrosterone, and Δ⁴-androsten-3,17-dione are active-site-directed irreversible inhibitors of Δ⁵-3-ketosteroid isomerase of $\text{P.}\text{testosteroni}$. The 17β-oxiranyl steroids rapidly inhibit the isomerase in a time-dependent manner which exhibits saturation kinetics. The enzyme is protected against inactivation by the competitive inhibitor 19-nortestosterone. In addition, prolonged dialysis against neutral buffer leads to no regeneration of enzyme activity. Fluorescent spectral changes associated with the incubation of the enzyme with the 17β-oxirane derived from d-equilenin indicate that there are two modes of binding for steroids to the isomerase. These results suggest that 17β-oxiranes may inhibit the enzyme by a mechanism similar to that for the previously studied spiro-3β-oxiranyl steroids.     

Basic aspects of and recent developments in telepathology in Europe, with specific emphasis on quality assurance

Telepathology is the diagnostic work of a pathologist from a distance and includes all specific fields of diagnostic pathology, such as frozen section services, expert consultation, cytometric and histometric measurement, and continuous education. For about 15 years experience has been collected at several universities in the United States and Europe based upon analog telephone lines (9.2 kbaud), digitized lines (ISDN, 64 kbaud), broad band connections (1.5 Mbaud) and the World Wide Web (28 kbaud). Potential use can be expected in the application of telepresentation, remote slide preparation, remote central diagnostics and telediscussion. The transfer of still images is well developed; that of live images is used in only a few institutions for frozen section services. The image quality and spatial resolution as well as the transfer speed are sufficient for expert consultations, morphometric measurements, quality assurance and education. All applications focus on discontinuous work flow. Although the European Community focuses on user needs and standardization aspects of telepathology by sponsoring a widespread telepathology project (Europath), implementation of telepathology into routine application in the continuous work flow has still to be developed. The technical equipment has still to be adjusted to the labor flow charts in routine pathologic diagnostic procedures. Telepathology seems to be the appropriate technique to offer both improvement in diagnostic quality and inclusion of the "control institution" into diagnostic responsibility.