Micro and nano-scale compartments guide the structural transition of silk protein monomers into silk fibers.

Silk is a unique, remarkably strong biomaterial made of simple protein building blocks. To date, no synthetic method has come close to reproducing the properties of natural silk, due to the complexity and insufficient understanding of the mechanism of the silk fiber formation. Here, we use a combination of bulk analytical techniques and nanoscale analytical methods, including nano-infrared spectroscopy coupled with atomic force microscopy, to probe the structural characteristics directly, transitions, and evolution of the associated mechanical properties of silk protein species corresponding to the supramolecular phase states inside the silkworm's silk gland. We found that the key step in silk-fiber production is the formation of nanoscale compartments that guide the structural transition of proteins from their native fold into crystalline ß-sheets. Remarkably, this process is reversible. Such reversibility enables the remodeling of the final mechanical characteristics of silk materials. These results open a new route for tailoring silk processing for a wide range of new material formats by controlling the structural transitions and self-assembly of the silk protein's supramolecular phases.

Fluorescent Properties of BODIPY Sensors Based on Photoinduced Electron Transfer.

Two boron-dipyrrin (BODIPY) based dyes with dimethylaminophenyl and carboxyphenyl substituents in 8-position of dipyrrin ligand have been synthesized and characterized. Photophysical and spectral properties of the obtained compounds have been investigated in water-ethanol mixture and water-cyclohexane system with variation of pH values. The equilibria constants of the compounds were identified by classical methods of acid-base titration. BODIPY bearing dimethylaminophenyl and carboxyphenyl subunits show deprotonation/protonation dependent fluorescence off/on-switching. The change of the emission could be mechanistically explained by a PET (photoinduced electron transfer) from the 8-substituent to the fluorophore. The present study demonstrates that BODIPY-based fluorescent sensors can be used to measure the pH in the range of 2-13 extending the scope of BODIPY dyes available as pH-indicators. Investigated compounds demonstrate weak dye-dye interaction allowing their cooperative usage as indicators.

High-dose-rate endobronchial brachytherapy in endobronchial metastatic malignant chondroid syringoma.

A 65-year-old man with malignant chondroid syringoma (MCS) was found to have pulmonary metastases in the form of multiple pulmonary nodules 4 years after wide excision and adjuvant radiotherapy of a primary abdominal wall tumor. Atelectasis of the lingula due to obstructive endobronchial metastasis, resistant to combination chemotherapy, led us to perform high-dose rate (HDR) endobronchial brachytherapy for the first time in this rare tumor with a favorable response. This case emphasizes the role of HDR brachytherapy as a palliative procedure in endobronchial tumors not responding to other treatment modalities, even those considered to be radioresistant.

Recurrent, self-limited, menstrual-associated bronchiolitis obliterans organizing pneumonia.

A 39-year-old woman presented with recurrent acute illness, characterized by high-grade fever, pleuritic chest pain, and unilateral nodular infiltrate on chest radiograph. During the follow-up period, there were six similar episodes, each starting 2 to 3 days prior to her menstrual period and resolving within 5 to 10 days. Persistent symptoms in the seventh episode led us to perform an open lung biopsy; the specimen showed histologic changes compatible with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). To the best of our knowledge, this is the first report describing BOOP in association with a menstrual period. This exceptional case emphasizes the wide and unexpected spectrum of this disease.

Incidence of bacteraemia following fibreoptic bronchoscopy.

Guidelines for antibiotic prophylaxis of infective endocarditis prior to fibreoptic bronchoscopy, are based on only five studies, which showed a bacteraemia rate of <1% among 291 patients studied. T his study was designed to expand the current data regarding the frequency of bacteraemia following fibreoptic bronchoscopy. Aerobic and anaerobic cultures of venous blood and of lavage fluid were drawn from 200 consecutive patients undergoing fibreoptic bronchoscopy without respiratory infection or antibiotic treatment prior to the procedure. The true bacteraemia rate was calculated after excluding probable "contaminated" blood cultures. A possible correlation between type of procedure performed during the bronchoscopy and occurrence of bacteraemia was investigated. Positive blood cultures were noted following 26 bronchoscopy examinations. Coagulase negative Staphylococcus was found in the cultures of 18 patients, coagulase positive Staphylococcus in 3 patients, nonhaemolytic streptococci and a Klebsiella species in 2 patients each, and beta haemolytic streptococcus in one patient. After exclusion of 13 "contaminated" specimens the bacteraemia rate was 6.5% (13/200 patients). This study showed a bacteraemia rate of 6.5%, significantly higher than previously recognized in a cohort of patients undergoing fibreoptic bronchoscopy without either pulmonary infection or an unusually high rate of invasive procedures. These findings should be taken into account in future evaluations of recommendations for antibiotic prophylaxis of endocarditis.

Pleural empyema: An unusual presentation of esophageal perforation.

A 67-year-old patient presented with pleural empyema as the sole manifestation of thoracic esophageal perforation, 2 weeks after accidental fish bone ingestion. Nonspecific chest pain and general deterioration, unusual presenting symptoms in themselves, accounted for the extreme delay in the diagnosis. The empyema was treated surgically, and the esophageal perforation conservatively. Despite the poor prognostic factors, the patient recovered completely after 50 days in hospital.

[A disorder of serotonin metabolism in patients in the acute period of nontraumatic intracranial hemorrhages]. / Narushenie obmena serotonina u bol'nykh v ostrom periode netravmaticheskikh vnutrimozgovykh krovoizliianii.

The indices of serotonin metabolism in cerebrospinal fluid (CSF) and blood were studied in 43 patients with nontraumatic intracerebral hemorrhage in the interval from 1 - 2 to 28 days after the onset of the disease. The considerable increase of tryptophan, serotonin and its main metabolite 5-hydroxyindoleacetic acid (5-HAA) in CSF and blood was found. The relationship between liquor and blood serum serotonin levels, hemorrhage focus size, severity and outcome of disease was also observed. There were no significant differences between serotonin, 5-HAA, free and bound serotonin levels in patients with the break of blood into different part of liquor space. The possible mechanisms of alteration of serotonin metabolism in patients with intracerebral hemorrhage were discussed.

[Mossbauer data on the effect of NAD.H on the state of iron in bacteria]. / Messbauérovskie dannye po vliianiiu NAD.H na sostoianie zheleza v bakteriiakh.

The state of Fe of bacterial cultures of different systematic positions (Bacillus megaterium, Bacillus polymyxa, Pseudomonas putida, Pseudomonas fluorescens, Alcaligenes faecalis, Arthrobacter siderocapsulatus) grown on the medium containing Fe(III) citrate (up to 100 mg/l) with additional or without NAD.H was studied. The samples were in damp air-dry, second moistened, dried at 383 K states. Spectra have been obtained at 290 K and 100-200 K. The studied microorganisms have two types of atoms of Fe(III) which dissociated into protoplasm or into cell slug at damp state. All studied microorganisms except Arthrobacter siderocapsulatus do not reduce iron at all variants of experiments. Arthrobacter siderocapsulatus reduces about 50% of cell iron only the presence of NAD.H creating two types of Fe(II) complexes firmly connected with cell.

[Serotonin metabolism in several hereditary extrapyramidal diseases]. / Osobennosti obmena serotonina pri nekotorykh nasledstvennykh ékstrapiramidal'nykh zabolevaniiakh

The authors studied the serotonin content in 43 patients with hereditary extrapyramidal diseases and in 30 normals (the control group). The thrombocyte serotonin was determined according to the modified Crawford method. The results of the study displayed that there was a highly significant drop in the level of serotonin in patients with torsion distonia (more expressed in subgroup 3, in patients with prevalent tonic disturbances and fixed pathological poses), and in akinetico-rigid variants of Huntington's chorea. In patients with hereditary pallidary degenerative diseases there was a tendency to a drop in the serotonin level.