Colorectal carcinoma antigens detected by hybridoma antibodies.

Hybridoma cells which secrete colorectal carcinoma-specific antibodies have been produced and used to study the antigenic structure of these tumor cells. Nineteen antibodies have been studied in detail, and 15 of these are colorectal carcinoma specific. Only two antibodies reactive with carcinoembryonic antigen (CEA) have been discovered and five other antibodies that react with distinct epitopes on the cell surface have been defined. Several antigens with distinct molecular characteristics have been shown to exist by use of hybridoma antibodies. Six hybridoma antibodies have been shown to mediate antibody-dependent cell-mediated cytotoxicity (ADCC).     

Diagnosis of Helicobacter pylori

The different invasive and noninvasive diagnostic tests for Helicobacter pylori have been applied mainly in emerging countries. Molecular methods have been developed, especially a test for detection of H. pylori and its clarithromycin resistance directly from stools. The long-term effects of eradication on histologic lesions have been studied in a meta-analysis and the prognostic value of post-treatment in gastric mucosa-associated lymphoid tissue lymphoma has been assessed. An operating link for gastritis assessment (the OLGA staging) has also been published. Attempts to simplify the urea breath test protocol have been made, and new stool antigen tests have been proposed and compared to those previously available.     

Imaging erythrocytes under physiological conditions by atomic force microscopy

Since its invention in the mid 1980s atomic force microscopy has revolutionised the way in which surfaces can be imaged. Close to atomic resolution has been achieved for some materials and numerous images of molecules on surfaces have been recorded. Atomic force microscopy has also been of benefit to biology where protein molecules on surfaces have been studied and even whole cells have been investigated. Here we report a study of red blood cells which have been imaged in a physiological medium. At high resolution, the underlying cytoskeleton of the blood cell has been resolved and flaws in the cytoskeleton structure may be observed. Comparison of the normal 'doughnut' shaped cells with swollen cells has been undertaken. Differences in both the global properties of the cells and in the local features in cytoskeleton structure have been observed.     

Interactions between platelet-surface glycoproteins. Identification of glycoproteins capable of binding to platelet surfaces.

1. Platelets have been isolated from plasma and their surface glycoconjugates radioactively-labelled using galactose oxidase and NaB3H4. 2. Conditions have been defined for optimal labelling of glycoproteins and a membrane fraction enriched in plasma membrane has been prepared and characterized by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 3. Desialylated glycoproteins that act as receptors to peanut agglutinin and lentil lectin have been purified from a detergent extract of plasma membrane. 4. Two glycosylated polypeptides that are able to bind to the surfaces of platelets have been identified and some characteristics of the binding have been investigated.     

Adenylate cyclase of the causative agent of plague: its purification and properties

Three forms of adenylate cyclase have been detected in Y. pestis: membrane-bound, cytoplasmic and extracellular. Extracellular adenylate cyclase has been purified so as to achieve a homogeneous state, and some of its physicochemical parameters have been investigated. In the process of purification the initial preparation of this enzyme has been subjected to heating at 100 degrees C for 15 minutes, fractionation with ammonium sulfate, and gel filtration on Sephadex G-100. The homogeneity of adenylate cyclase has been confirmed by electrophoresis in 7.5% polyacrylamide gel and precipitation by the plague agglutinating serum. The enzyme has been found to have a molecular weight of 30,000 daltons and to show the optimum activity at pH 7.0-7.2 and at a temperature between 37 and 40 degrees C. Monospecific rabbit serum to the homogeneous preparation of adenylate cyclase has been obtained.     

Linked Cross Sectional Schemes for Estimating Growth of Children

For estimation of growth, the efficiency of linked cross sectional scheme has been compared with pure longitudinal and cross sectional schemes. The relevant estimation theory has been developed and the expressions for the optimum estimators alongwith their variances have been derived. It has been observed that for estimation of growth, the linked cross-sectional scheme has been observed to be less efficient as compared to pure longitudinal scheme but more efficient than pure cross-sectional scheme.     

THE ROTTING OF APPLES BY GLOEOSPORIUM PERENNANS ZELLER & CHILDS

The extent of rotting of commercially stored Cox's Orange Pippin apples by Gloeosporium species has been severe in recent years. G. perennans has been found to be mainly responsible.
Tree infections of this fungus have usually been found to be prevalent in the orchards on farms where storage losses of fruit have occurred, and conidia of G. perennans have been found on cankers at all seasons during the year. Winter as well as summer pruning cuts have been found to become infected. Detached leaves of Cox's Orange Pippin have been successfully inoculated with G. perennans in the laboratory and the fungus has also been found on dead detached leaves in the orchard after picking time. Considerable variations have been found in the susceptibility to rotting of samples of different varieties of apple and samples of Cox's Orange Pippin apples from different orchards. Periodic loading of fruit with spores after picking has shown that resistance declines with length of storage. Wide variation in the time at which rotting commences in commercially stored samples has been observed. A series of inoculations on picked and unpicked immature fruit has shown that the apple loses its resistance to attack on picking. Lenticels which are impermeable to gaseous exchange have been shown to be resistant to penetration by the fungus. Temperature affects the development of lenticel rotting by G. perennans , infection being most rapid at temperatures of about 20°. Rotting can occur at 0° C.     

Productivity improvement in xanthan gum fermentation using multiple substrate optimization

A novel and more comprehensive formulation of the optimal control problem that reflects the operational requirements of a typical industrial fermentation has been proposed in this work. This formulation has been applied to a fed-batch bioreactor with three control variables, i.e., feed rates of carbon source, nitrogen source, and an oxygen source, to result in a 148.7% increase in product formation. Xanthan gum production using Xanthomonas campestris has been used as the model system for this optimization study, and the liquid-phase oxygen supply strategy has been used to supply oxygen to the fermentation. The formulated optimization problem has several constraints associated with it due to the nature of the system. A robust stochastic technique, differential evolution, has been used to solve this challenging optimization problem. The infinite dimensional optimization problem has been approximated to a finite dimensional one by control vector parametrization. The state constraints that are path constraints have been addressed by using penalty functions and by integrating them over the total duration to ensure a feasible solution. End point constraints on final working volume of the reactor and on the final residual concentrations of carbon and nitrogen sources have been included in the problem formulation. Further, the toxicity of the oxygen source, H(2)O(2), has been addressed by imposing a constraint on its maximum usable concentration. In addition, the initial volume of the bioreactor contents and feed concentrations have been handled as decision variables, which has enabled a well-grounded choice for their values from the optimization procedure; adhoc values are normally used in the industry. All results obtained by simulation have been validated experimentally with good agreements between experimental and simulated values.     

Melanocyte-directed enzyme prodrug therapy (MDEPT): development of a targeted treatment for malignant melanoma.

A novel prodrug rationally designed to function as a tyrosinase substrate has been synthesised to allow targeted treatment of malignant melanoma. This agent has been evaluated for tyrosinase-mediated drug release, and has been shown to act in the desired manner. Furthermore, differential cytotoxicity has been demonstrated in cell lines which express tyrosinase and those which do not.     

New antibiotic resistance Loci in the ribosomal region of yeast mitochondrial DNA

A large number of mitochondrial antibiotic-resistant mutants have been isolated following mutagenesis with manganese. These include several different phenotypic classes of mutants, as distinguished by cross-resistance patterns, that have been found to be allelic at cap1 or ery1; some have been found to be heteroallelic.--Seven chloramphenicol-resistant mutants have been identified that are nonallelic by recombination tests with the three loci (cap1, spi1 and ery1) previously identified in the ribosomal region. Four of these are allelic with each other and define a new locus, cap3; two others are allelic and define another new locus, cap2; the seventh maps at yet a different locus, cap4. One new spiramycin-resistant mutant has been identified that defines still another new locus, spi2. A variety of genetic techniques have been used to map these loci within the ribosomal region of the mitochondrial genome.-Manganese has been shown to be effective in inducing the mutation from omega(-) to omega(n) in many mutants that experience a simultaneous mutation at the closely linked cap1 locus. The omega(n) mutation has also been described in the cap4 mutant, and this locus has been shown to be more closely linked to omega than cap1 is to omega.     

Persistence of bacterial pathogens as a physiological phenomenon

The complex ecosystem of humans and microbes has been presented as an associative symbiosis based on a mutual support of symbionts with different consequences for them. Conditions for the persistence of bacteria have been defined: their resistance to environmental factors, antagonism in biocenosis, and stability to withstand host defense mechanisms. The key role of bacterial peptidoglycan has been defined for their survival in an infected organism, and the classification for persistent mechanisms of pathogens has been given. The group of bacterial secreted protease providing microbial resistance to defense factors of the organism has been described. Host colonizing resistance has been presented as a physiological regulatory system controlling bacterial penetration into an organism. Regulatory mechanisms for bacterial persistence have been discussed.     

Using artificially generated spectral data to improve protein secondary structure prediction from Fourier transform infrared spectra of proteins

Secondary structures of proteins have been predicted using neural networks from their Fourier transform infrared spectra. To improve the generalization ability of the neural networks, the training data set has been artificially increased by linear interpolation. The leave-one-out approach has been used to demonstrate the applicability of the method. Bayesian regularization has been used to train the neural networks and the predictions have been further improved by the maximum-likelihood estimation method. The networks have been tested and standard error of prediction (SEP) of 4.19% for alpha helix, 3.49% for beta sheet, and 3.15% for turns have been achieved. The results indicate that there is a significant decrease in the SEP for each type of structure parameter compared to previous works.     

Synthesis, resolution and charge-donor properties of six tryptophan analogues.

In order to investigate the special function of tryptophan in peptide hormones, six tryptophan analogues have been synthesized, in which structural resemblance has been grossly retained and potentially essential properties have only partially been varied. The L-enantiomers have been isolated after enzymatic digestion of racemic dipeptide derivatives, and charge-transfer properties of the compounds have been studied.     

Cyclodextrins micrometric powders obtained by supercritical fluid processing

Supercritical fluid technology offers the possibility to produce dry powder formulations of biocompatible materials, overcoming the drawbacks of classical micronization processes. In this work, Supercritical Assisted Atomization (SAA) has been used to micronize alpha-cyclodextrin (alpha-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD). Some process parameters, such as precipitation temperature and solute concentration in the liquid solution, have been studied to evaluate their influence on morphology and size of precipitated particles. Cyclodextrins (CDs) micronization has been successful: well-defined spherical microparticles of alpha-CD and HP-beta-CD have been produced. Particle size analysis revealed that sharp distributions have been obtained: 95% of particles have diameters ranging between 0.1 and 5 microm for both CDs. X-ray and DSC analyses have been also performed to investigate CDs modifications induced by SAA processing: amorphous particles have been obtained in both cases, whereas raw alpha-CD was crystalline and raw HP-beta-CD was amorphous.     

Examination of substrate and product inhibition kinetics on the production of ethanol by suspended and immobilized cell reactors

Kinetic expressions for the fermentative production of relatively high concentrations [12% (w/v)] of ethanol have been examined. Several expressions which account for both substrate and product inhibition have been formulated, and have been applied to suspended cell and immobilized cell reactors. Experimental data have been used to validate the kinetic expressions used, and the impact of combined inhibition on optimal reactor configuration has been assessed. The process implications of combined substrate and product inhibition for suspended and immobilized cell systems have been discussed.     

Interferons: Purification and Physicochemical Aspects

Antiviral interferon activity in any one species can be exhibited by a variety of substances that differ in their physical and chemical properties, but the nature of these differences is not understood. Conditions that can lead to the formation of diverse types of interferons have been outlined. Reasons have been adduced why, for certain purposes, purification of interferons is desirable or even necessary, and examples have been presented to show how and to what extent this has been achieved. In spite of some very high purification factors, not a single interferon has been obtained as a pure substance. Therefore, all available knowledge of physical and chemical properties has been obtained by indirect means.     

Levels of understanding in ecology: interspecific competition and community ecology

Abstract Ecological interpretation has been subject to several divisive controversies, involving, for example, the significance of density dependence and interspecific competition as ecological processes. Generally, resolution has been obtained through compromise and concensus or calls for yet more data. Essentially, both sides in the discussion are seen to have been correct to some extent. As a consequence the debates have been portrayed widely as having been sterile. We agree, but only because they have been conducted at a level so superficial that the relevance of the original criticisms to the theoretical structure of ecology has not been widely appreciated, nor resolved. Debate that deals with ecological generalizations must be conducted at a level appropriate to such aims.     

pH-sensitive hydrogel based on a novel photocross-linkable copolymer

A pH sensitive hydrogel has been prepared by a UV irradiation technique. Starting polymer was the PHM (poly hydroxyethylaspartamide methacrylated) obtained from polyaspartamide (PHEA) partially derivatized with methacrylic anhydride (MA). This new copolymer has been further derivatized with succinic anhydride (SA) to obtain PHM-SA that has been cross-linked by UV irradiation to form a pH sensitive hydrogel. The network, recovered after washing as a powder, has been been characterized by FT-IR spectrophotometry and particle size distribution analysis. Moreover, to have information about water affinity of the prepared sample, swelling measurements have been carried out in aqueous media mimicking biological fluids. The possibility to employ the prepared hydrogel as a pH-sensitive drug delivery system (DDS) has been investigated. In particular, ibuprofen ((S)(+)4-isobutyl-alpha-methylphenyl-acetic acid), chosen as a model drug, has been entrapped into the PHM-SA hydrogel, and in vitro release studies have showed that its release rate depends on different swelling of the network as a function of the environmental pH.     

Spatial distribution of oil in groundnut and sunflower seeds by nuclear magnetic resonance imaging

Abstract. The nuclear magnetic resonance imaging technique has been used to obtain images of different transverse and vertical sections in groundnut and sunflower seeds. Separate images have been obtained for oil and water components in the seeds. The spatial distribution of oil and water inside the seed has been obtained from the detailed analysis of the images. In the immature groundnut seeds obtained commercially, complementary oil and water distributions have been observed. Attempts have been made to explain these results.     

Acute oxygen supply by infusion of hemoglobin solutions.

Preparations of 6% human hemoglobin have been investigated for 4 years. While the oxygen dissociation curve is shifted to the left, the hemoglobin solution has been shown to deliver oxygen adequately to the tissues in animal studies. Intracorporeal fate has been investigated by 131-I tagging, and the hemoglobin has not been found to accumulate in the tissues. Intravascular half-life has varied between 1.5 and 3.5 hours.