The Mucolytic Activity of Amides: A New Approach to Mucus Dispersion

A method which will reduce significantly the viscosity of epithelial mucus is essential to the physiological mechanisms involved in the mobilization and removal of such secretions. The life expectancy of patients with chronic pulmonary conditions and cystic fibrosis has been considerably increased and consequently the problem of liquefying mucin acquires new importance. In view of these considerations, as well as to facilitate research into the structural relationship of the glycoprotein macromolecule, a systematic investigation of mucolysis was undertaken using gastric mucin. Three amides, carbamide, acetamide and formamide, were found to dissolve gastric gel mucin with minimal degradation, and rapidly disperse the viscous secretions produced in pathological conditions of the tracheobronchial tree. Their effect on secretions from patients with cystic fibrosis and bronchiectasis is dramatic, and within five minutes of adding the reagent the flow time was reduced by at least 95%. Clinical studies were carried out with carbamide (urea in anhydrous, lyophilized, sterile powder form) in 32 patients with a variety of bronchial conditions, including chronic bronchitis, cystic fibrosis, asthma, bronchiectasis and emphysema. With the concentrations used, no irritant, bronchospastic or other reactions were observed.It is concluded that amides of this type have at least two actions on the epithelial mucous secretion: (1) breakage of the three-dimensional gel structure and (2) a slower reduction in viscosity followed by solution of the solid material.     

The Activity Approach and Psychology

Some of the most essential and currently promising achievements in the psychology of the 1930s, resulting from the application of the methodological principle of the unity of consciousness and activity, are here discriminated and analyzed. The starting conditions for a child's mastery of speech on the basis of initially practical communicative contacts with adults and material objects are set forth; these conditions have been ignored by cultural-historical theory and by nonactivity approaches. It is concluded that speech is not an activity. The relation between activity and behavior is examined.     

Blood Pressure-Lowering Peptides from Neo-Fermented Buckwheat Sprouts: A New Approach to Estimating ACE-Inhibitory Activity

Neo-fermented buckwheat sprouts (neo-FBS) contain angiotensin-converting enzyme (ACE) inhibitors and vasodilators with blood pressure-lowering (BPL) properties in spontaneously hypertensive rats (SHRs). In this study, we investigated antihypertensive mechanisms of six BPL peptides isolated from neo-FBS (FBPs) by a vasorelaxation assay and conventional in vitro, in vivo, and a new ex vivo ACE inhibitory assays. Some FBPs demonstrated moderate endothelium-dependent vasorelaxation in SHR thoracic aorta and all FBPs mildly inhibited ACE in vitro. Orally administered FBPs strongly inhibited ACE in SHR tissues. To investigate detailed ACE-inhibitory mechanism of FBPs in living body tissues, we performed the ex vivo assay by using endothelium-denuded thoracic aorta rings isolated from SHRs, which demonstrated that FBPs at low concentration effectively inhibited ACE in thoracic aorta tissue and suppressed angiotensin II-mediated vasoconstriction directly associated with BPL. These results indicate that the main BPL mechanism of FBP was ACE inhibition in living body tissues, suggesting that high FBP''s bioavailability including absorption, tissue affinity, and tissue accumulation was responsible for the superior ACE inhibition in vivo. We propose that our ex vivo assay is an efficient and reliable method for evaluating ACE-inhibitory mechanism responsible for BPL activity in vivo.     

丹参酮抗肿瘤研究新进展

丹参酮是一类从传统中药材丹参中提取的醌类化合物,近年研究发现其具有多种生物活性,包括抗氧化,抗炎,抑制增殖,诱导凋亡等作用,本文针对丹参酮自2008年至今的国内外抗肿瘤研究进行综述。     

A New Approach to the Analysis of Normal Muscle Electrical Activity during Walking in Humans

Introduction of short-term disturbances into the biomechanical structure of the human gait with simultaneous recording of the muscle electrical activity has been used to demonstrate that the human body has an intraspinal locomotor program consisting of an inhibition period, when afferent stimuli cause no response, and an excitation period, when the responses are expressed. The electromyographic profile of the leg muscles of subjects walking on a horizontal surface, up stairs, and down stairs may be divided into three zones. The H and M zones (the highest and moderate activities, respectively) correspond to the centrally programmed excitation period, and the L zone (low-amplitude activity), to the centrally programmed inhibition period. The difference between the former two zones is that the activity in the H zone is regular, whereas the M-zone activity is irregular and varies depending on biomechanical conditions. Apparently, the steady activity in the H zone is determined by the combined effect of the spinal generator of locomotion movements, cyclic supraspinal stimuli, and various (mainly proprioceptive) afferent impulses from the leg. An increase in the M-zone activity is mainly determined by afferent stimuli.     

The Sterility Testing of Aminoglycosides: A New Approach Using Enzymic Inactivation

The inactivation of various aminoglycosides prior to sterility testing has been studied. The preparation of the enzyme used in the inactivation, a 3-N-acetyl transferase of wide substrate specificity from Escherichia coli JR 225, is described. The enzyme is partially purified and some of its kinetic parameters described. The extent of the inactivation of the individual aminoglycosides can be related to the physiological efficiency of the enzyme. The lyophilization of the components of the inactivating system is successful when undertaken individually, but not together.     

Circadian Locomotor Activity in Freshwater Decapods: An Ecological Approach

Circadian rhythms of locomotor activity shown by freshwater decapods display different patterns among crayfish, Procambarus, and crabs, when exposed to artificial light-dark cycles. Crayfish are mainly nocturnal while a crepuscular activity is observed in crabs of the genus Pseudothelphusa. In constant darkness, free running rhythms are displayed in unimodal or bimodal patterns by crayfish Procambarus; however, Pseudothelphusa continues to show bimodal rhythms. The many studies using locomotor activity indicate that the rhythm in freshwater crabs is circadian in nature, but that a multioscillatory system may be controlling the overt rhythm. In the present study, the implications of different locomotor activity patterns are analyzed in selected freshwater decapods with regard to the interactions between light and the organisms. Crabs and crayfish are commonly found in similar habitats, often sharing the same environment; however, different patterns of locomotor activity as well as different sensitivities of the bouts of activity with regard to entrainment by light, indicate that distinct temporal niches may exist that result in temporal exclusion or low competition.     

Marine Bacterium Derived Lipopeptides: Characterization and Cytotoxic Activity Against Cancer Cell Lines

A marine Bacillus circulans DMS-2 was able to grow and produce biosurfactant on glucose mineral salts medium (GMSM) with a reduction in the surface tension up to 27 mN m⁻¹. The microorganism produced 1.64 ± 0.1 g l⁻¹ of crude biosurfactant. The lipopeptide nature of the produced biosurfactant was confirmed by primulin and ninhydrin assays using High Performance Thin Layer Chromatography (HPTLC). Preparative thin layer chromatography (TLC) was performed to purify the lipopeptides from the crude biosurfactant. The critical micelle concentrations (CMC) of the crude and purified products were found to be 90 and 40 mg l⁻¹ respectively. Fourier transform infrared spectrophotometer (FTIR) and matrix assisted laser desorption/ionization time of flight (MALDI-ToF) mass spectral analysis revealed the identity of the produced lipopeptides as surfactin (m/z 1,023 Da) and fengycin (m/z 1,495 Da) isoforms. The purified marine lipopeptides displayed a significant antiproliferative activity against the human colon cancer cell lines HCT-15 (IC₅₀ 80 μg ml⁻¹) and HT-29 (IC₅₀ 120 μg ml⁻¹).     

Induction Cardiac Pacing: A New Approach

A new approach to induction cardiac pacing using a “skin tunnel” transformer has been developed and used in a patient. Initial results are encouraging. If the system proves reliable in the long term it may have important applications in the delivery of power to implanted artificial organs.     

The Elusive Embryo: How Women and Men Approach New Reproductive Technologies

The Elusive Embryo: How Women and Men Approach New Reproductive Technologies. Gay Becker. Berkeley: University of California Press, 2000. 320 pp.     

The Biocompatibility of Porous vs Non-Porous Bone Cements: A New Methodological Approach

Composite cements have been shown to be biocompatible, bioactive, with good mechanical properties and capability to bind to the bone. Despite these interesting characteristic, in vivo studies on animal models are still incomplete and ultrastructural data are lacking. The acquisition of new ultrastructural data is hampered by uncertainties in the methods of preparation of histological samples due to the use of resins that melt methacrylate present in bone cement composition. A new porous acrylic cement composed of polymethyl-metacrylate (PMMA) and β-tricalcium-phosphate (p-TCP) was developed and tested on an animal model. The cement was implanted in femurs of 8 New Zealand White rabbits, which were observed for 8 weeks before their sacrifice. Histological samples were prepared with an infiltration process of LR white resin and then the specimens were studied by X-rays, histology and scanning electron microscopy (SEM). As a control, an acrylic standard cement, commonly used in clinical procedures, was chosen. Radiographic ultrastructural and histological exams have allowed finding an excellent biocompatibility of the new porous cement. The high degree of osteointegration was demonstrated by growth of neo-created bone tissue inside the cement sample. Local or systemic toxicity signs were not detected. The present work shows that the proposed procedure for the evaluation of biocompatibility, based on the use of LR white resin allows to make a thorough and objective assessment of the biocompatibility of porous and non-porous bone cements.Key words: calcium phosphate cement, osteointegration, biocompatibility, osteoconduction, porosity     

Qualitative Research Design: An Interactive Approach

Qualitative Research Design: An Interactive Approach. Joseph A. Maxwell. Thousand Oaks, CA: Sage Publications, 1996. 155 pp.     

Origins of Life Research: a Bibliometric Approach

This study explores the collaborative nature and interdisciplinarity of the origin(s) of life (OoL) research community. Although OoL research is one of the oldest topics in philosophy, religion, and science; to date there has been no review of the field utilizing bibliometric measures. A dataset of 5647 publications that are tagged as OoL, astrobiology, exobiology, and prebiotic chemistry is analyzed. The most prolific authors (Raulin, Ehrenfreund, McKay, Cleaves, Cockell, Lazcano, etc.), most cited scholars and their articles (Miller 1953, Gilbert 1986, Chyba & Sagan 1992, W?chtersh?user 1988, etc.), and popular journals (Origins of Life and Evolution of Biospheres and Astrobiology) for OoL research are identified. Moreover, interdisciplinary research conducted through research networks, institutions (NASA, Caltech, University of Arizona, University of Washington, CNRS, etc.), and keywords & concepts (astrobiology, life, Mars, amino acid, prebiotic chemistry, evolution, RNA) are explored.