Controlled trial of methylprednisolone pulses and low dose oral prednisone for the minimal change nephrotic syndrome.

In a multicentre, randomised, prospective trial 89 patients (67 children and 22 adults) with the minimal change nephrotic syndrome were treated with three intravenous pulses of methylprednisolone followed by low dose oral prednisone for six months (group given methylprednisolone) or with high dose oral prednisone for four weeks followed by low dose oral prednisone for five months (control group). Five patients in the group given methylprednisolone and one in the control group did not respond initially. The time to response was shorter in children treated with methylprednisolone. No significant differences between the two groups were observed in the number of patients who relapsed or number of relapses per patient per year. Patients given methylprednisolone tended to relapse earlier than patients in the control group. Side effects related to treatment were significantly fewer in the group given methylprednisolone than in the control group. These data suggest that a short course of methylprednisolone pulses followed by low dose oral prednisone is only marginally less effective than a regimen of high dose oral steroids but can improve the ratio of risk to benefit associated with treatment of the minimal change nephrotic syndrome.     

Biosynthesis of immunoglobulin A (IgA). Secretion and addition of carbohydrate to monomer and polymer forms of a mouse myeloma protein

Cell suspensions of mouse plasma-cell tumour MOPC 315 secreting predominantly IgA (immunoglobulin A) monomer and dimer were incubated with radioactive leucine, mannose, galactose and fucose for various periods of time. The amounts of secreted and intracellular immunoglobulins were measured by co-precipitation with specific antibody, and the molecular species present were assessed by electrophoresis in polyacrylamide gels. Analysis of the secreted myeloma protein demonstrated that monomer and dimer IgA molecules are identical with respect to carbohydrate composition and rate of secretion. Within the cell, the myeloma protein is almost entirely accounted for by monomer units which either leave the cell as such or are polymerized with the addition of J chain close to the time of secretion. The results support the concept of a stepwise addition of carbohydrate residues to IgA immunoglobulin during the process of secretion. Similar patterns of carbohydrate assembly were found for the monomer or dimer molecules. Mannose residues are added at an early stage, whereas fucose is added close to the time of secretion. Galactose is also added early, but some may also be incorporated at a later stage. Control of IgA polymerization is considered unlikely to reflect regulation at the level of carbohydrate addition, and it is suggested that the critical controlling factor is the J chain.     

Expression of HOX homeogenes in human neuroblastoma cell culture lines

Mammalian genes containing a class-I homeobox (HOX genes) are highly expressed in the embryonic nervous system. As a first step towards the molecular analysis of the role these genes play in neural cells, we studied the expression of four human HOX genes in five neuroblastoma (NB) cell lines - SK-N-BE, CHP-134, IMR-32, SK-N-SH and LAN-1 - during the process of differentiation induced by treatment with retinoic acid (RA). The four genes, HOX1D, 2F, 3E and 4B, located at corresponding positions in the four HOX loci, share a high degree of sequence similarity with the Drosophila Deformed homeotic gene and constitute a homology group, group 10. One of these genes, HOX1D, is not expressed in the cells used, whereas the other three are highly expressed in untreated and RA-induced NB cells, even though the expression pattern in the various lines is slightly different for the three genes. Our analysis reveals a complex and specific expression pattern in these lines, paving the way to an identification of different NB-cell populations by means of specific HOX gene expression schemes. On the other hand, in every line studied, morphological maturation toward a neuronal differentiated phenotype appears to be associated with increased HOX gene expression.     

Inhibition by verapamil of neutrophil responses to formylmethionylleucylphenylalanine and phorbol myristate acetate. Mechanisms involving Ca2+ changes, cyclic AMP and protein kinase C

Verapamil inhibits in human neutrophils the respiratory burst, the secretion and the change of transmembrane potential induced by formylmethionylleucylphenylalanine, a Ca2+-dependent stimulus, and by phorbol myristate acetate, a Ca2+-independent stimulus. Besides the blocking of Ca2+ channels, many mechanisms are responsible for the inhibition of neutrophil responses. In fact, verapamil (i) increases the intracellular cAMP concentration, potentiates the cAMP response induced by the chemotactic peptide and induces the appearance of a cAMP response also when the stimulant is phorbol myristate acetate; (ii) causes a decrease of Ca2+ association to cell membranes, so depleting the pools of exchangeable Ca2+ and depressing the 'Ca2+ response' in terms of rise in [Ca2+]i monitored with Quin 2 and of rapid mobilization from cell membranes monitored by chlorotetracycline fluorescence change; (iii) inhibits the Ca2+-activated phospholipid-dependent protein kinase C. The data, discussed in relation to the biochemical mechanisms of the stimulus-response coupling, are compatible with the hypothesis of an involvement of the activation of protein kinase C as key step in the sequence of transduction events for the induction of many neutrophil functions.     

Thaimycins,new anthelmintic and antiprotozoal antibiotics produced by Streptomyces michiganensis var. amylolyticus var. nova

Summary A new microorganism, isolated in our laboratories and identified as Streptomyces michiganensis var. amylolyticus var. nova is described.Thaimycins can be obtained by submerged fermentation of this microorganism on a suitable culture medium.Three new related compounds, thaimycins A, B and C have been obtained and characterized by their physical and chemical properties.Data on the antiprotozoal and anthelmintic activities in vitro as well as in vivo are reported.     

A new chemical mechanism catalyzed by a mutated aldehyde dehydrogenase.

NAD(P) aldehyde dehydrogenases (EC 1.2.1.3) are a family of enzymes that oxidize a wide variety of aldehydes into acid or activated acid compounds. Using site-directed mutagenesis, the essential nucleophilic Cys 149 in the NAD-dependent phosphorylating glyceraldehyde-3-phosphate dehydrogenase from Escherichia coli has been replaced by alanine. Not unexpectedly, the resulting mutant no longer shows any oxidoreduction phosphorylating activity. The same mutation, however, endows the enzyme with a novel oxidoreduction nonphosphorylating activity, converting glyceraldehyde 3-phosphate into 3-phosphoglycerate. Our study further provides evidence for an alternative mechanism in which the true substrate is the gem-diol entity instead of the aldehyde form. This implies that no acylenzyme intermediate is formed during the catalytic event. Therefore, the mutant C149A is a new enzyme which catalyzes a distinct reaction with a chemical mechanism different from that of its parent phosphorylating glyceraldehyde-3-phosphate dehydrogenase. This finding demonstrates the possibility of an alternative route for the chemical reaction catalyzed by classical nonphosphorylating aldehyde dehydrogenases.     

Restriction site mapping for three or more enzymes

Restriction site mapping requires a generator to put forwardpossible maps and a constraint checker to reject false maps.Ideally these combine to give an algorithm which calculatesa sound and complete solution set. Three algorithms for generationare presented and compared. Two decompose a multi-enzyme problem(3) into subproblems. The constraint checker is based on separationtheory. Some insights into the extent of constraint checkinginvolved in and the feasibility of more checking for three ormore enzymes are discussed. The trade-off between computationtime and the soundness of the solution set is examined. Received on July 30, 1989; accepted on April 4, 1990     

Optimized enzymatic synthesis of geranyl butyrate with lipase AY from Candida rugosa

Response surface methodology (RSM) and five-level, five-variable central composite rotatable design (CCRD) were used to evaluate the effects of synthetic variables, such as reaction time (1-9 h), temperature (25-65 degrees C), enzyme amount (10-50%), substrate molar ratio of geraniol to tributyrin (1:0.33-1:1), and added water amount (0-20%) on molar percent yield of geranyl butyrate, using lipase AY from Candida rugosa. Reaction time and temperature were the most important variables and substrate molar ratio had no effect on percent molar conversion. Based on contour plots, optimum conditions were: reaction time 9 h, temperature 35 degrees C, enzyme amount 50%, substrate molar ratio 1:0.33, and added water 10%. The predicted value was 100% and actual experimental value was 96.8% molar conversion. (c) 1996 John Wiley & Sons, Inc.