Some properties of lactate dehydrogenase found in human urine

1. Urinary lactate dehydrogenase was concentrated and subjected to starchblock electrophoresis. The isoenzyme pattern obtained was shown to be similar to that of the kidney cortex and medulla but different from that of the bladder and kidney pelvis. 2. The values for the relative activity and Michaelis constant of urinary lactate dehydrogenase were similar to those for kidney cortex and medulla but significantly different from those obtained for bladder and kidney pelvis. 3. The molecular weight of urinary lactate dehydrogenase was estimated by thin-layer chromatogtaphy on Sephadex G-200. The values obtained for several samples of urine ranged from 129 000 to 155 000 and were very close to that of the crystalline rabbit-muscle enzyme (140 000). 4. The question of the possible origin of urinary lactate dehydrogenase is discussed and the conclusion drawn that the kidney and not the plasma is the most likely source.     

Purification of the oligosaccharide-cleaving enzymes of Flavobacterium meningosepticum.

Four oligosaccharide chain-cleaving enzymes, including two new endoglycosidases distinct from endo-beta-acetylglucosaminidase (Endo) F1, have been identified and purified to homogeneity from cultural filtrates of Flavobacterium meningosepticum. FPLC-directed hydrophobic-interaction chromatography in conjunction with high-resolution ion-exchange chromatography provided a more simple, rapid method for the isolation of endoglycosidase F1, F2 and F3, and the amidase, peptide-N4-N-acetyl-beta-D-glucosaminyl)-asparagine amidase (PNGase F), in greater than 50% yield. The specificity of PNGase F and Endo F1 are well established. Endo F2 and Endo F3 represent new distinct endoglycosidases that prefer complex as compared to high-mannose asparagine-linked glycans. Endo F2 cleaved biantennary oligosaccharides, whereas Endo F3 cleaved both bi- and triantennary oligosaccharides.     

Carboxypeptidase H. A regulatory peptide-processing enzyme produced by human hepatoma Hep G2 cells

Human hepatoma (Hep G2) cells have been shown to secrete nanogram quantities of carboxypeptidase N (Grimwood, B. G., Plummer, T. H., Jr., and Tarentino, A. (1988) J. Biol. Chem. 263, 14397-14401). A second carboxypeptidase with an acidic pH optimum (pH 5.5) is also secreted at levels 2-3-fold greater than carboxypeptidase N. This enzyme was partially purified from the conditioned medium and compared with pure bovine pituitary carboxypeptidase H. The two enzymes behaved in a similar fashion in DE52 ion-exchange chromatography and on gel filtration, with the Hep G2 enzyme being slightly larger than the bovine pituitary enzyme (52-54 versus 50-52 kDa). Both enzymes hydrolyzed COOH-terminal basic amino acids from typical synthetic substrates as well as from natural leuenkephalin peptides and were identical based on pH activity profiles, inhibition by EDTA or guanidinoethyl mercaptosuccinic acid, and stimulation by Co2+ ions. Inhibition of enzyme secretion from Hep G2 cells by tunicamycin indicated that the Hep G2 enzyme was glycosylated. This finding was confirmed by a parallel deglycosylation of the Hep G2 and bovine pituitary carboxypeptidase H enzymes with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Immunoblots using mouse antiserum to bovine pituitary carboxypeptidase H revealed that the Hep G2 enzyme was immunocross-reactive with the bovine enzyme but was slightly larger in size (54 versus 52 kDa). Continuous [35S]methionine labeling and purification to near homogeneity using an affinity matrix corroborated the observations that the secreted Hep G2 carboxypeptidase H was slightly larger than bovine pituitary carboxypeptidase H. The Hep G2-secreted enzyme in pulse-chase experiments was initially detected intracellularly after a 15-min pulse as a single protein of about 54 kDa and was present in the 30-min chase medium with no evidence for pre- or postsecretion proteolytic processing. The human adrenergic cell line IMR-32 continuously labeled with [35S]methionine also secreted carboxypeptidase H of the same size as the Hep G2 enzyme.     

A Papionin Multilevel Society as a Model for Hominin Social Evolution

Multilevel societies are unique in their ability to facilitate the maintenance of strong and consistent social bonds among some individuals while allowing separation among others, which may be especially important when social and sexual bonds carry significant and reliable benefits to individuals within social groups. Here we examine the importance of social and sexual bonds in the multilevel society of hamadryas baboons (Papio hamadryas) and apply these principles to social evolution in Plio-Pleistocene hominins. The behavior, adaptations, and socioecology of baboons (Papio spp.) have long been recognized as providing an important comparative sample to elucidate the processes of human evolution, and the social system of hamadryas baboons in particular shares even more similarities with humans than that of other baboons. Here we draw parallels between processes during the evolution of hamadryas social organization and those characterizing late Pliocene or early Pleistocene hominins, most likely Homo erectus. The higher costs of reproduction faced by female Homo erectus, exacerbated by an increased reliance on difficult to acquire, nutrient-dense foods, are commonly thought to have been alleviated by a strengthening of male–female bonds (via male provisioning and the evolution of monogamy) or by the assistance of older, postreproductive females (via grandmothering). We suggest that both of these social arrangements could have been present in Plio-Pleistocene hominins if we assume the development of a multilevel society such as that in hamadryas baboons. The evolution of a multilevel society thus underlies the adaptive potential for the complexity that we see in modern human social organization.     

Quantification of angiogenesis in estrogen receptor-positive and negative breast carcinoma

Background

The objective of this study was to evaluate angiogenesis according to CD34 antigen expression in estrogen receptor (ER)-positive and negative breast carcinomas.

Methods

This study comprised 64 cases of infiltrating ductal carcinoma in postmenopausal women divided into two groups: Group A: ER-positive, n = 35; and Group B: ER-negative, n = 29. The anti-CD34 monoclonal antibody was used as a marker for endothelial cells. Microvessel count was carried out in 10 fields per slide using a 40× objective lens (magnification 400×). Statistical analysis of the data was performed using Student's t-test (p < 0.05).

Results

The mean number of vessels stained with the anti-CD34 antibody in the estrogen receptor-positive and negative tumors was 23.51 ± 1.15 and 40.24 ± 0.42, respectively. The number of microvessels was significantly greater in the estrogen receptor-negative tumors (p < 0.001).

Conclusion

ER-negative tumors have significantly greater CD34 antigen expression compared to ER-positive tumors.

     

Differential responsiveness to immunoablative therapy in refractory rheumatoid arthritis is associated with level and avidity of anti-cyclic citrullinated protein autoantibodies: a case study

In order to identify pathogenic correlates of refractory rheumatoid arthritis (RA), antibodies against anti-cyclic citrullinated protein (ACPAs) were investigated in RA patients in whom the dysregulated immune system had been ablated by high-dose chemotherapy (HDC) and autologous haematopoietic stem cell transplantation (HSCT). Six patients with refractory RA were extensively characterized in terms of levels of total immunoglobulins, RA-specific autoantibodies (ACPAs and rheumatoid factor) and antibodies against rubella, tetanus toxoid (TT) and phosphorylcholine before and after HDC plus HSCT. Additionally, the avidity of ACPAs was measured before and after treatment and compared with the avidity of TT antibodies following repeated immunizations. Synovial biopsies were obtained by arthroscopy before HDC plus HSCT, and analyzed by immunohistochemistry. In the three patients with clinically long-lasting responses to HDC plus HSCT (median 423 days), significant reductions in ACPA-IgG levels after therapy were observed (median level dropped from 215 to 34 arbitrary units/ml; P = 0.05). In contrast, stable ACPA-IgG levels were observed in three patients who relapsed shortly after HDC plus HSCT (median of 67 days). Clinical responders had ACPA-IgG of lower avidity (r = 0.75; P = 0.08) and higher degree of inflammation histologically (r = 0.73; P = 0.09). Relapse (after 38 to 530 days) in all patients was preceded by rising levels of low avidity ACPA-IgG (after 30 to 388 days), in contrast to the stable titres of high avidity TT antibodies. In conclusion, humoral autoimmune responses were differentially modulated by immunoablative therapy in patients with synovial inflammation and low avidity ACPA-IgG autoantibodies as compared with patients with high levels of high avidity ACPA-IgG. The distinct clinical disease course after immunoablative therapy based on levels and avidity of ACPA-IgG indicates that refractory RA is not a single disease entity.