Inhibition of A and B N-acetyl-beta-D-glucosaminidase urinary isoenzymes by urea

A urinary fraction which inhibits the activity of N-acetyl-beta-D-glucosaminidase (NAG) has been isolated and identified as being urea. Usually present in high concentration, urea appears to be the only urinary component responsible for the frequently observed urinary NAG inhibition. The inhibition of the two urinary NAG isoenzymes A and B is competitive with respective Ki values of about 70 mmol/l and 60 mmol/l. With routine assay conditions, it seems that a dilution of urine prior to enzyme assay is sufficient to abolish the inhibition of the two isoenzymes A and B by endogenous urea.

Nuclear matrix modifications at different stages of infection by herpes simplex virus type 1

In BHK-21 cells infected with herpes simplex virus type 1 many virus-induced proteins were found attached to the nuclear matrix. To understand the role of this cell fraction during virogenesis, matrix-associated proteins were analysed at different stages of infection. All the immediate-early protein species were bound to the nuclear matrix and their association with this structure was stable. During the first few hours of infection, the pattern of virus-induced proteins attached to the nuclear matrix remained identical, indicating that polypeptides from the early group are not associated with this cell fraction. Among the late proteins, which are generally structural proteins, 60% of the nuclear proteins were tightly bound to the nuclear matrix. This suggests that the nuclear matrix is involved in at least two different events during virogenesis, regulation of viral infection and assembly of viral capsids.

Isolation of cDNA and genomic clones encoding human pro-alpha 1 (III) collagen. Partial characterization of the 3' end region of the gene

A cDNA library constructed from human fibroblast poly(A+) RNA was screened for the identification of chimeric molecules bearing collagen-specific sequences. Analysis of three of the resulting positive clones showed that they encoded for the COOH-terminal propeptide region of the human Type III collagen. In addition, three overlapping clones covering more than 21 kilobases of the Type III gene were isolated from Charon 4A libraries of human genomic fragments. Identity between these and the cDNA clones was obtained by direct DNA sequencing. Establishment of the exon/intron arrangement of the Type III gene was obtained by electron microscopic analysis in conjunction with sequencing of selected genomic regions. Sequence comparison with other collagen genes confirmed some evolutionary features of this important family of proteins. Finally, the collinearity of two mRNA transcripts with 3' noncoding region length polymorphism was established.

Fine structural analysis of the human pro-alpha 1 (I) collagen gene. Promoter structure, AluI repeats, and polymorphic transcripts

The human pro-alpha 1(I) collagen gene is 18 kilobases long, and its coding information is subdivided in 51 exons. We have recently reported a detailed analysis of this elaborate structure. Here we describe the exact termini of the gene as well as its 5' flanking sequences (promoter region). Sequence comparison between the human and mouse pro-alpha 1(I) gene showed an unusual highly conserved region 5' to the initiation site of transcription, which may be important for pro-alpha 1(I) collagen expression. Sequence comparison between the pro-alpha 1(I) and other collagen genes revealed the presence of a conserved secondary structure possibly implicated in the regulation of collagen mRNA translation and/or collagen secretion. Two short repetitive sequences closely associated with the pro-alpha 1(I) gene have been identified to be different members of the AluI family of repeats. Like the independently co-expressed pro-alpha 2(I) collagen gene, the analysis of the last exon has revealed that the pro-alpha 1(I) gene transcribes two different mRNAs in cultured fibroblasts. The colinearity and exact location of the termini of these transcripts, as well as their monogenic nature, have been conclusively determined.

[Cardiac manifestations of Lyme disease. Apropos of 2 cases]

Lyme disease, a well-known entity in the United States, has featured only rarely in the French literature. We report two cases from the Cardiology Department with acute symptomatic atrio-ventricular block. The illness begins with migratory chronic erythema, which is the best marker of the condition. This is followed by neurological, joint and cardiac manifestations. Cardiac involvement consists essentially in A-V block of varying severity, which rapidly regresses. Until the recent discovery of the arthropod vector responsible (Ixodes dammini), the diagnosis was clinical and was confirmed by negative serological results for the other infectious agents. Penicillin and tetracycline are effective at the skin lesion stage. It is important to recognise this condition since there is no case of complete A-V block lasting longer than 2 weeks.

Human pro alpha 1(I) collagen gene structure reveals evolutionary conservation of a pattern of introns and exons

The collagens represent an interesting example of a structurally related but genetically distinct family of proteins. Type I, the most abundant of the vertebrate collagens, comprises two pro alpha 1(I) chains and one pro alpha 2(I) chain, each containing terminal propeptides and a central domain of 338 (Gly, X, Y) repeats. The structure of the chicken pro alpha 2(I) gene shows an intriguing relationship between exon organization and the arrangement of (Gly, X, Y) repeats (see ref. 2 for review). This has led to the suggestion that the collagens evolved from a common ancestral unit of 54 base pairs (bp). Here we present the structure of the entire human pro alpha 1(I) gene and compare this with the chicken pro alpha 2(I). The exon arrangement of the two genes is remarkably similar, although the human pro alpha 1(I) is more compact because of the shorter length of its introns. The data strongly support the notion that the type I genes have evolved from an ancestral multi-exon unit, and that once the gene was translated, a strong evolutionary pressure caused it to maintain this elaborate structure.

[Azoles. 12. Pyrazole carbolic acid thioamides]

Morpholids, N-methylpiperazids, piperidids and pyrrolidids of 5-methyl, 3,5-dimethyl-1-phenyl-4-pyrazolthioacetic acid and 3,5-dimethyl-1-phenyl-4-pyrazolcarbonic acid 4-12 are obtained by the Willgerodt-Kindler procedure. The oxothioamids 13-19 result as the intermediate products of the synthesis of thioamids 4-10. The compounds 4, 5, 8, 9, 11, 14 and 17 do not respond to Mycobacterium tuberculosis H37Rv. The thioamids 4, 8 and 11 are of slight toxicity (LD50 greater than 2.8 g/kg, albino-Swiss mice) and inhibit the Carrageenin oedema of the Wistar rat claw minor than phyenylbutazon and indometacin.

[Study of in vivo cellular metabolism by phosphorus 31 nuclear magnetic resonance]

Phosphorus-31 nuclear magnetic resonance spectroscopy has been recently increasingly used to study cellular metabolism in a manner respecting the cell integrity. Intrinsic advantages of the phosphorus nucleus for in vivo NMR studies are discussed in this review together with some selected applications. A particular emphasis is layed on metabolite identification and quantitation (relative and absolute concentrations), the measurement of intracellular pH and the problem of cellular compartmentation. The determination of metabolite fluxes under normal and abnormal biological and physiological conditions, and the in vivo direct measurement by saturation transfer techniques of kinetic parameters for enzymatic reactions at equilibrium, are illustrated by several examples taken from the available literature and work carried out in this laboratory. Whenever possible, and appropriate, the NMR approach has been compared with other more classical techniques of investigation. The future and the potentialities of phosphorus-31 NMR study of intact biological systems, the clinical applications and the foreseeable interfacing with imaging techniques are evaluated. The concept of "functional imaging" versus "anatomic imaging" is proposed to illustrate the impact of this new technology in the understanding of cellular mechanisms, not only in the intact cell but also in whole tissues or organs after excision or in living animals and human.

On the specificity of the two forms of human serum alpha-L-fucosidase

All normal sera exhibiting either normal or low activities contain two forms of alpha-L-fucosidase (F1 and F2). These two forms, isolated from either type of serum, have respectively similar properties, but the low-activity sera contain a major proportion of the thermolabile, less-acidic form, F1. The specificities for natural substrates (glycoproteins and oligosaccharides) and for synthetic fucosides have been studied. All types of alpha-L-fucosidase linkages (1,2; 1,3; 1,4 and 1,6) are split by the form F2. The specificity of the form F1 is more restricted. Only alpha(1,3) and some types of alpha(1,2) and alpha(1,4) fucosyl linkages are split.

Properties of two forms of alpha-L-fucosidase isolated from normal human sera with low and high enzymatic activity

Studies on human alpha-L-fucosidase were performed on normal and low activity sera. After DEAE-Sephacel chromatography, two major forms of enzyme have been characterized in both types of sera. These enzymatic forms were different with respect to their thermostability and electrofocusing behaviour. The less acidic form (I) was thermolabile. In contrast, the more acidic one (II) was thermostable. But the forms I and II had respectively similar properties when isolated from either normal or low activity sera. These results suggest the presence in both types of sera of two major forms of alpha-L-fucosidase but in variable proportions. The low activity sera contained a major proportion of the thermolabile less acidic form when compared with normal activity sera.

[Measurement of linear exposure nominal pose used in curietherapy]

The idea, and subsequent construction, of a dose rate meter for measuring linear exposure dose originated in those pilot centres of Curietherapie which wished to replace radium by the artificial radionucleides, Irdium-192, Caesium-137 etc. The aparatus makes it possible to measure, directly and quickly, the activity of a specified length of a linear source, a measurement which has only been possible until now by dividing the exposure dose by the length whose activity it is desired to know. If the dose-rate obtained by these two methods agrees, this apparatus shortens the time for which the sources need to be handled, thereby reducing the danger of irradiation to staff and technicians. The apparatus is thus able to reveal heterogeneity of activity along the length of a line-source. In the specific case of Iridium, our experience shows that wires which have been used in several applications may develop mechanical bends and constrictions, which can lead to fluctuation in dose rate along their length. The apparatus was first constructed in 1967, after preliminary experiments in 1965. As Curietherapy has become more widely used, the apparatus has undergone many modifications which is more precise and specific than it was initially. At the present time it can only be used with Iridium as wire, and with Caesium in the form of trains of seeds (corresponding to the AGS sources) or needles. Nevertheless, a third scale is under consideration, for use with newer radioelements, which may be used in future.

Recombination of carbon monoxide with hemoglobin after flash photolysis of the carboxyderivative in mixed solvents at subzero temperature

The kinetics of recombination of carbon monoxide to hemoglobin produced by total flash photolysis of its carboxyderivative are studied at low temperatures (down to --55 degrees C) in mixed hydroalcoholic solvents. The rates are found to be different in two solvents used, namely ethylene glycol/buffer and methanol/buffer; for the former, the rates at subzero temperatures are simply explained by cooling and are consistent with the activation energy as measured in aqueous solution, while those in methanol/buffer show evidence of a specific solvent effect. Values are reported for the rate constants and activation energies in the two solvents.