Calculation of the optimal surface area for amphiphile molecules using the hard core method

In this work, we have calculated the optimal surface area per amphiphile molecule using a two-dimensional gas of electric dipoles interacting with hard The optimal surface area can be evaluated according to a formula (in the two-body approximation) or as a root of an equation (in the three-body approximation). If the equation has more than one positive root, which is greater than the hard core area, then a polydisperse dimensional distribution of supramolecular aggregates is possible.     

Two different Escherichia coli capsular polysaccharide depolymerases each associated with one of the coliphage phi K5 and phi K20

The Escherichia coli capsular polysaccharides (K antigens) K5 and K20 are known as primary receptors for the coliphage phi K5 and phi K20, respectively. A host range study of the phage revealed that E. coli K5 strains were not only lysed by phi K5 but also by phi K20, and furthermore that the E. coli K95 test strain was attacked by phi K5 in addition to K5 strains. In order to find out whether the phage can degrade the K antigens, the interaction of the phage with isolated polysaccharides was studied. It could be demonstrated that phi K5 was able to depolymerize the K5 and K95 polysaccharides and that phi K20 showed degrading activity towards the antigens K20 and K5. Obviously, each of the phages was associated with two different enzyme systems which enabled them to recognize and depolymerize chemically unrelated polysaccharides.     

Developmental competence of domestic cat follicular oocytes after fertilization in vitro

Empirical evaluation of variables affecting oocyte collection, in vitro fertilization, and embryo transfer resulted in establishing a successful procedure for the artificial production of offspring in the domestic cat. Female cats were treated with pregnant mare's serum gonadotropin (PMSG, 150 IU) followed 72 or 80 h later with 100 or 200 IU human chorionic gonadotropin (hCG). After laparoscopic collection, follicular oocytes were inseminated in vitro with ejaculated, processed spermatozoa, cultured (37 degrees C, 5% CO2), and then examined for evidence of fertilization. Two- to 4-cell stage embryos were transferred to the oviducts of oocyte donors. Oocyte donor cats and naturally mated controls also were subjected to sequential laparoscopic examinations and blood sampling to assess corpora lutea (CL) function. At 24-30 h of culture, fewer (p less than 0.001) degenerate oocytes were observed in cats receiving 100 IU hCG (8.2%) compared to those receiving 200 IU (20.6%), regardless of the PMSG-hCG interval. Overall fertilization (48.1%) and cleavage (45.2%, at 30 h post-insemination) rates were greatest following an 80-h PMSG-hCG interval combined with the 100 IU hCG dose. Five of the 6 cats receiving 6 to 18 embryos became pregnant and produced from 1 to 4 kittens/litter. Gonadotropin-treated females subjected to follicular aspiration produced morphologically normal CL and circulating progesterone patterns that were qualitatively similar (p greater than 0.05) to control cats. These data indicate that domestic cat follicular oocytes are capable of fertilization in vitro, but success is dependent on both the timing and dose of the hCG stimulus. Follicles subjected to aspiration appear capable of forming normal, functional CL and the birth of live young after embryo transfer unequivocally demonstrates, for the first time, the developmental competence of in vitro-fertilized carnivore oocytes.     

Correlation between low CSA plasma concentration and severity of acute GvHD in bone marrow transplantation

Between 1982 and 1986 51 patients were treated with ciclosporin a (CSA) to prevent graft versus host disease (GvHD) after bone marrow transplantation (BMT). Major side effects of the drug were tremor, hypertension, hepatotoxicity and nephrotoxicity. Acute GvHD 0 degree to II degree occurred in 80% of our patients, and GvHD III degree and IV degree in 20% despite the use of CSA. Two to four days before the onset of GvHD, CSA serum levels were significantly lower on the average in patients who developed GvHD III degree and IV degree compared to the others. Our data indicate that plasma CSA concentrations higher than 250 ng/ml should be achieved to reduce the severity of GvHD after BMT.     

Binding and degradation of proteoglycans by cultured arterial smooth muscle cells. II. Binding sites of proteoglycans on the cell surface

Exogenous proteoglycans stained for electron microscopy with colloidal gold and/or cuprolinic blue bind to the surface of cultured arterial smooth muscle cells at two different sites. (I) About 20% of the proteoglycans adsorbed to the cells from the culture medium interact as monomeric and multimeric proteoglycans with smooth or coated membrane areas. (II) The bulk of exogenous proteoglycans exhibits high affinity binding to cell membrane-associated 10 nm fibrils containing or being closely associated with fibronectin and to collagen. It is suggested that the self association of proteoglycans and their binding to the cell membrane and to cell surface-associated fibronectin and collagen are important for maintaining an appropriate micro-environment for the cultured cells.     

Characterization of an amidated form of pancreatic polypeptide from the daddy sculpin (Cottus scorpius)

The primary structure of pancreatic polypeptide from the teleostean fish, Cottus scorpius (daddy sculpin) was established as: YPPQPESPGGNASPEDWAKYHAAVRHYVNLITRQRYNH2 The presence of a COOH-terminally alpha-amidated amino acid was established using an HPLC method of general applicability. Although the peptide shows strong homology towards anglerfish pancreatic polypeptide (86%), homology towards porcine peptide YY (PYY) (61%) and porcine neuropeptide Y (NPY) (61%) was greater than towards porcine pancreatic polypeptide (PP) (47%). This result supports suggestions that the gene duplication events which led to PP, NPY and PYY formation took place after the time of divergence of fish and mammals.     

Light- and cytidine-dependent phosphatidylinositol synthesis in photoreceptor cells of the rat

Incorporation of [3H]inositol into phosphatidylinositol (Pl) in isolated rat retinas is enhanced by light and by the addition of cytidine to the incubation media. In retinas preincubated with [3H]inositol in dark, [3H]inositol was chased into Pl in light by addition of unlabeled cytidine and was chased out of Pl in light by addition of unlabeled cytidine plus inositol. Autoradiograms of retinas show a heavy density of silver grains over photoreceptor cell inner segments (with chase-in) and a loss of labeling (with chase-out). Exogenous cytidine and inositol were shown to enhance not only the turnover of Pl within photoreceptor cells but the synthesis of Pl as well; in media supplemented with these precursors, approximately 50% of [14C]glycerol and 25% of [32Pi]incorporated into lipid in light were associated with Pl. These results suggest that availability of both cytidine and inositol may play a role in the light-dependent changes in Pl metabolism within photoreceptor cells.     

Identification of Tn2401, a transposon encoding multiresistance to aminoglycosides

A transposable element, Tn2401, was found in a clinical isolate of Pseudomonas aeruginosa. Tn2401 had a size of 7190 nucleotides and encoded aminoglycoside 3'-phosphotransferase and aminoglycoside 6'-N-acetyltransferase. The sequence encoding the former enzyme was homologous with that of Tn903. Pseudomonas aeruginosa strains harbouring this transposon were resistant to kanamycin, neomycin, lividomycin, ribostamycin, paromomycin, netilmycin, tobramycin, dibekacin, gentamicin, sisomicin, and butirosin.