The different electrophoretic forms of post gamma-globulin their antigenic identity and their structural variability.

Post gamma-globulin, first described as a constant component of protein of cerebrospinal fluid and urine from patients with tubular disorders has also been found in other biological fluids. Post gamma-globulin from a single individual always migrated as several bands after storage. Three electrophoretic forms, immunochemically identical, have been isolated by gel chromatography, preparative continuous flow electrophoresis and ion-exchange chromatography. Their molecular weight was found to be approximately between 11 000 to 12 000. No difference between the three forms could be detected. The N-terminal amino acids were found to be Lys, Arg and Leu respectively for the three forms of post gamma-globulin. The "slow" and "fast" forms of post gamma-globulin seemed to differ by elimination of small basic peptides or amino acids from the N-terminal end of the protein. No enzymatic activity of post gamma-globulin was found, but this requires further investigations.

The use of preparative continuous flow electrophoresis to study low molecular weight proteins in urine.

The authors propose a convenient method for the separation of low molecular weight proteins, present in tubular urines. In particular, the method is used for the purification of beta2 microglobulin, after one recycling, and also for the isolation of the various post-gamma globulins which can later be separated on DEAE Sephadex.

Lead poisoning in monkeys: functional and histopathological alterations of the kidneys.

Ten monkeys (Macacus Irus) were given 0--15 mg of lead acetate (in drinking water) 6 days a week for 9 months. Two of the monkeys were also put on a low calcium diet with 6 mg of lead acetate/day. The blood lead level usually increased from the third month according to the dose of lead ingested and more quickly in monkeys deprived of calcium. Some of the monkeys showed signs of alteration in protein glomerular filtration and/or proximal tubular reabsorption. Studies using optical and electron microscopy showed distinct pathological changes in the proximal tubular epithelium where heavy deposits of lead were seen in the nuclei.

Chromosomal abnormalities in lymphocytes from monkeys poisoned with lead.

Cynomolgus monkeys (Macaca irus) were given 0, 1.5, 6 or 15 mg of lead acetate 6 days a week for 16 months. Another group, also receiving 6 mg, was kept on a low-calcium diet. Each experimental group consisted of 2 monkeys. Chromosome analysis on cultured lymphocytes was carried out after 3, 10 and 16 months of lead treatment. The frequency of severe abnormalities (dicentrics, rings, translocations and exchanges) was significantly increased only in the group on a low calcium diet, whereas "light" abnormalities (gaps and fragments) increased with time in all groups receiving lead irrespective of the diet. The blood lead data indicate the severity of the lead poisoning.

Neutrophil chemotactic activity is modulated by human cystatin C, an inhibitor of cysteine proteases.

Cystatin C, a cysteine proteinase inhibitor has recently been suggested to be a potent regulator of inflammatory processes and may act in defense against viral and bacterial infections. Two common forms of the protein were purified from the urine of a patient having received a renal transplant. The slow form of cystatin C possessed the N-terminal tetrapeptide Lys Pro Pro Arg, which was cleaved in the fast form. This peptide sequence, called postin, was synthesized. The three molecules, slow and fast forms of cystatin and the synthetic peptide, were tested for their effects on the migration activity of human polymorphonuclear neutrophils (PMNs). The slow form was found to display both chemotactic and chemokinetic activities, while the fast form and postin were only chemokinetic. Nevertheless, all the substances could induce a "motile" morphology. In addition, the two forms of cystatin C were powerful inhibitors of PMN chemotaxis induced by complement-derived chemotactic factors. This suggests that cystatin C in its two different cleaved forms and the N-terminal tetrapeptide can modulate PMN locomotion. Cysteine proteases may therefore play a role in neutrophil migration activity.

Environmental influences on the composition and structure of the freshwater mussels in shallow lakes in the Cuiabá River floodplain.

The maintenance of the freshwater mussels' community in lakes is determined by abiotic factors at the local scale and at regional scale by interspecific relations between the larvae of bivalves and fish host. Whereas the distribution pattern at local scale, our goal was to understand the abundance and community composition of bivalves and relate the environmental agents structuring this community. We sampled 20 lakes in the floodplain of the Cuiabá River using a standardized method of sampling. To evaluate the effect of environment on the community we applied multivariate inferential analyses. We found 1.143 individuals alive belonging into six species distributed at the family Hyriidae, Mycetopodidae, Sphaeridae and Corbiculidae. The results showed that in the Pantanal the bivalve assemblage structure is influenced locally by organic matter and particle size, variables that reflect the intense interactions between water-sediment. However it is important to emphasize that these environmental characteristics are the result of the dynamics of this system which is dependent on the flood pulse, a regional factor.

Determinants of pediatric care utilization.

The purpose of this paper is to understand the determinants of utilization of pediatric care--care rendered to children by all physicians. Multivariate techniques are employed to examine four measures of pediatric care utilization in a national sample of children between the ages of 1 and 5. These measures are the probability of contacting a physician within the past year, the probability of obtaining a preventive physical examination within the past year, the number of office visits to physicians in private practice by children with positive visits, and the average quality of these visits.

Identification of an IgD-like surface immunoglobulin on rabbit lymphocytes.

Rabbit immunoglobulin antigen receptor molecules were analyzed by electrophoresis in sodium dodecyl sulfate polyacrylamide gels. By sequential precipitation, using first anti-mu and then anti-L chain antisera, two different immunogloublins of similar molecular weight could be demonstrated. After tryptic digestion, two fractions were identified: an IgMs and an Fab fragment, the latter appearing after a few minutes of incubation. Thus, as in man and in the mouse, two main immunoglobulin antigen receptors were found in the rabbit. One receptor on rabbit lymphocytes is an IgMs molecule, and the other is easily split in the hinge region like human and mouse IgD receptors. In addition, a molecule similar to the mouse Fc receptor was nonspecifically precipitated.

The expression of human beta2-microglobulin on human spermatozoa.

The expression of human beta2-microglobulin was detected on human spermatozoa from 7 donors using a cytotoxicity assay and indirect immunofluorescence. Inhibition experiments using purified beta2-microglobulin demonstrated the specificities of these reactions. We were able to localize beta2-microglobulin on human spermatozoa on the post-acrosomal region at a similar location to those described for HL-A antigen and for early embryonic antigen +t12, but also at the end of the intermediary piece and the beginning of the tail.

Biochemical characterization of an Fc receptor of rabbit lymphocytes.

Isolation of Fc-binding molecules was performed by complexing IgG antibodies and the corresponding antigens in lysates of radiolabeled rabbit lymphoid cells. A single-chain molecule of 110 000 apparent mol. wt. (unreduced) or 120 000 (reduced) was observed in sodium dodecyl sulfate polyacrylamide gel electrophoresis when the antibodies were in the IgG form but not as F(ab')2. This molecule was very susceptible to proteolysis, but the fragments thus produced remained associated by disulfide bridges, and the binding properties of the molecule were conserved. The molecule and its proteolytic fragments (mol. wts. 75 000, 45 000 and 20 000) were very similar to those obtained for the mouse Fc receptor under similar conditions, and therefore the molecule was designated as rabbit Fc receptor. Among several precipitating systems used, some Ig-anti-Ig complexes appeared to be the most efficient in coprecipitating the rabbit Fc receptor. Remarkably high titers of Fc receptor were found on lymphocyte membrane of infected rabbits, in agreement with a possible role of this molecule in immune regulation.

A rapid and sensitive method using immunological nephelometric analysis to evaluate the gel-filtration method. (Application to the diagnosis of rubella).

Immunological nephelometric analysis has been shown to be a more sensitive method than either immunoelectrophoresis or gel-diffusion for testing the gel-filtration method of human immunoglobulins sera. This method has the advantages of facility, rapidity and sensitivity. We have compared this method to radial immunodiffusion. This method can be applied to locate with precision any antigens after gel-filtration or ion-exchange chromatography.

[beta2-Microglobulin and experimental nephropathies in macacus monkey (author's transl)]. / Néphropathies expérimentales et beta2-microglobuline chez le singe.

In the monkey, the action of four renal toxics : lead acetate, sodium maleate, cadmium chloride and sodium chromate was compared. Tubulopathies were obtained only with cadmium chloride and sodium chromate with in the best cases about 16 mg/l of beta2-microglobulin (beta2m) in the urine. Monkey and human beta2m have the same molecular weight and are antigenically similar. However, they differed in electrophoretic mobility, the monkey beta2m being slightly more cathodic.

Low molecular weight proteinuria.

Low molecular weight (LMW) proteinurias vary widely in their microprotein composition. In general, there is little correlation between a given microprotein composition and a defined clinical disease (with the exception of the predominant beta-2-microglobulin in Wilson's disease). Free immunoglobulin light chains are a practically invariable component of, and may be the only detectable LMW protein in, 'tubular' proteinuria. The origins and significance of some frequently occurring urinary LMW proteins are discussed.

Evidence for an absence of cross-reactivity between the human beta2-microblobulin and human IgG allotypes and subclasses.

Six beta2-microglobulins were isolated from the urine of six patients with renal tubular dysfunction. Cross-reactivity between these beta2-microglobulins and antigenic determinants of different IgG allotypes and subclasses was investigated. No evidence of cross-reactivity was found. Some hypotheses are discussed concerning these results.

Isolation and characterization of rat kidney alanine aminopeptidase.

Rat alanine aminopeptidase was purified from kidney by isolation of the brush border membrane with CaCl2 followed by differential centrifugation and tryptic proteolysis. It is a glycoprotein with a molecular weight of approximately 210,000 daltons comprising two 110,000-dalton subunits and has an amino acid composition similar to that of the human enzyme. Two zinc atoms are covalently bound to each protein subunit.

[beta2-Microglobulin in human seminal fluid (author's transl)]. / La beta2-microglobuline dans le liquide séminal.

The expression of human beta2-microglobulin (beta2m) on human spermatozoa cell surface was investigated by cytotoxicity and immunofluorescence tests. beta2m was also found in human seminal fluid by use of immunochemical techniques. Seminal fluids obtained from couples with infertility problems were tested for beta2m, albumin and total proteins concentration. A higher level of beta-2m was found in azoospermia compared with that of normal sperms.

A rapid two-step purification of rat cystatin C, one major inhibitor of cysteine proteinases.

Rat cystatin C was purified to apparent homogeneity from rat urine after induction of a tubular dysfunction with sodium chromate. Twentyfold concentrated urine was chromatographed by a rapid purification procedure. A two-step purification including affinity chromatography on carboxymethyl papain- Sepharose and high-resolution anion exchange chromatography was developed. The purified protein has an apparent molecular mass of 15 kDa and pI of 10.2; its aminoacid composition was similar to human cystatin C. As opposed to previous data, purified urinary rat cystatin C did not contain significant amounts of carbohydrate. Antisera against rat cystatin C, raised in rabbits, partially cross-reacted with human and mouse cystatin C, indicating their antigenic similarities. Like human cystatin C, native rat cystatin C, named slow form, is degraded into a more acidic form, called fast form, by a loss of N-terminal amino acids; fast form displayed a pI of 9.4.