Lucigenin chemiluminescence and its relationship to mitochondrial respiration in phagocytic cells

Unstimulated alveolar macrophages, but not polymorphonuclear leukocytes, elicit chemiluminescence from lucigenin which cannot be entirely accounted for by the resting level of superoxide generation. This chemiluminescence was inhibited by both superoxide scavengers and inhibitors of mitochondrial respiration. Although 12-O-tetradecanoyl phorbol-13-acetate addition resulted in a significant increase in cellular superoxide generation, an unexpected decrease in lucigenin chemiluminescence was noted. These results suggest that mitochondria in alveolar macrophages may be a site of lucigenin accumulation and dioxygenation and that 12-O-tetradecanoyl phorbol-13-acetate may modulate this activity.     

The association of ovarian cancer with various genetic markers

The distribution of blood groups AB0, Rh, P1, MN and Haptoglobins among ovarian cancer patients was studied. Significant associations between ovarian cancer and B(III) and MN blood groups as well as the 2-1 variant of haptoglobin were revealed. These data should be kept in mind when forming the high risk groups among population, in relation to ovarian cancer.     

Evolution of Alu repeats: dynamics of distribution in genome

A mathematical model of evolutionary dynamics of Alu repeats' number in the human genome has been worked out. The model permitted us to observe the dynamics of propagation of Alu repeats within the genome and to evaluate such important parameters of the process mentioned as the rates of transposition (insertion of new copies into the genome) and excision of repeats. The peculiarities of the control of Alu repeats' number in the genome have been discussed, based on the data obtained.     

Propionate metabolism in a methanogenic enrichment culture. Direct reductive carboxylation and acetogenesis pathways

Abstract Serial dilutions of methanogenic sludges in propionate medium gave a methanogenic non-acetoclastic enrichment degrading 1 mol of propionate to 1.6 mol of acetate and 0.17 mol of methane, with a transient accumulation of butyrate. NMR recordings showed the conversion of [2-¹³C]- and [3-¹³C]-propionate to [3-¹³C]- and [4-¹³C]-butyrate, respectively, thus demonstrating a reductive carboxylation of propionate to butyrate. The labelling found in the accumulated acetate and fermentation balances also suggested that reductive carboxylation was the major pathway involved in propionate conversion to acetate.     

Astrocyte death in organotypic cultures of fetal spinal cord from rats with unilateral micromelia

Growth and differentiation of neurons and glia in spinal cord explants of 16 days old rat fetuses with teratogen-induced left-sided micromelia were studied. Progressive destruction of astrocytes that differentiate in interstitial zone of cultures was observed in 37% of explants of the left side, while the development was normal in cultures of the right side. Possible mechanisms leading to destruction of astrocytes in cultures of spinal cord regions that innervate anomalous limbs are discussed.     

Neuron-specific and state-specific differences in calcium homeostasis regulate the generation and degeneration of neuronal architecture

Many stimuli (e.g., neurotransmitters and electrical activity) regulate neuromorphogenesis by changing intracellular calcium. The ionophore A23187 was employed as a receptor-independent method to investigate neuronal calcium homeostasis. Distinctive neuron-specific (B5 versus B19) and state-specific (growing versus non-growing) differences in calcium homeostasis were observed in cultured identified Helisoma neurons. Fura-2 studies revealed that A23187 induced a transient rise in intracellular calcium in growing neurons B5 but a sustained rise in growing neurons B19. In stable-state (non-growing) cells A23187 evoked only a transient calcium rise. Both neuron-specific and state-specific differences in calcium homeostasis were dependent on extracellular sodium. Morphological studies also indicated that such differences in calcium-regulatory capacity can have profound consequences on the generation and degeneration of neuronal architecture.     

Organization of hindbrain segments in the zebrafish embryo

To learn how neural segments are structured in a simple vertebrate, we have characterized the embryonic zebrafish hindbrain with a library of monoclonal antibodies. Two regions repeat in an alternating pattern along a series of seven segments. One, the neuromere centers, contains the first basal plate neurons to develop and the first neuropil. The other region, surrounding the segment boundaries, contains the first neurons to develop in the alar plate. The projection patterns of these neurons differ: those in the segment centers have descending axons, while those in the border regions form ventral commissures. A row of glial fiber bundles forms a curtain-like structure between each center and border region. Specific features of the individual hindbrain segments in the series arise within this general framework. We suggest that a cryptic simplicity underlies the eventual complex structure that develops from this region of the CNS.     

Modulation of sulfated proteoglycan synthesis and collagen gene expression by chondrocytes grown in the presence of bFGF alone or combined with IGF1

Prepubertal rabbit epiphyseal chondrocytes were grown in high density primary culture for 3 d. They were then incubated for 3 additional d in serum-free culture medium to which bFGF (1-50 ng/ml) was added. During the last 24 h incubation period, either IGF1 (1-80 ng/ml) or Insulin (1-5 micrograms/ml) was added to the culture medium. Chondrocyte DNA was significantly augmented with the increasing concentration of bFGF used, thus confirming its mitogenic effect on chondrocytes. On the other hand, bFGF was also shown to modulate the phenotypic expression of the chondrocytes. The 35S-sulfate incorporation into newly synthesized proteoglycans by the cultured cells decreased in a dose-dependent manner with bFGF concentration used. In addition, chondrocyte collagen gene expression was also shown to be modulated by bFGF. Total RNA extracted from the cultured cells was analyzed by dot blot and Northern blot with cDNA probes encoding for alpha 1 II and alpha 1 I procollagen chains. A significant lower level of type II collagen mRNA, the marker of chondrocytic phenotype, was observed when cells were grown in the presence of bFGF while the level of type I mRNA remained unchanged. When IGF1 or a high concentration of insulin was added to the cells during the last 24 h of incubation with bFGF, sulfated proteoglycan synthesis, as well as collagen type II mRNA level, were significantly stimulated when compared with chondrocytes incubated with bFGF alone. In conclusion, in the present experimental conditions, bFGF appears to be a growth promoting agent for chondrocytes in vitro with dedifferentiating action on chondrocyte phenotype. IGF1 or insulin used at a high concentration can prevent the dedifferentiating effect of bFGF without inhibiting its stimulating effect on chondrocyte DNA synthesis.     

Does a torn anterior cruciate ligament lead to change in the central nervous drive of the knee extensors?

Integrated surface electromyograms of the three superficial parts of the quadriceps and isokinetic knee extensor maximum torque and power production were recorded simultaneously and at different angular velocities in both legs in 11 male subjects with unilateral tear of the anterior cruciate ligament. The cross-sectional area (CSA) of the thigh and its muscular components were measured by computerized tomography. The principal findings were a small but significant decrease in quadriceps CSA on the affected side; a decreased active, but not passive, range of movement; decreased mechanical output, whether or not corrected for differences in CSA; and decreased electromyographic activity--particularly in rectus femoris. These findings suggest that the reason for the decreased maximum and total knee extensor performance seen in these patients is a change in knee joint receptor afferent inflow.