Histochemical procedures for the simultaneous visualization of sialic acid,its side chainO-acyl variants andO-sulphate ester

Journal of Molecular Histology -     

FEMORAL SHAFT FRACTURES—A Study of Closed Reduction and Open Treatment

A comparative study was made of 58 cases of closed femoral shaft fractures treated by skeletal traction, and 24 cases of closed femoral shaft fractures treated by open reduction with internal fixation.Although complications occurred in some cases, intramedullary nailing appeared to be the most satisfactory method, resulting in primary union, in decreased time of recumbency and time in hospital, in earlier ambulation and in less residual disability.Success of intramedullary nailing depends largely upon adequate training or experience of the surgeon in the technical operative aspects of the procedure and in postoperative management.Placing supplemental autogenous iliac bone chips at the fracture site in closed femoral fractures in which intramedullary nailing is performed appears to enhance callus formation and bony consolidation.Skeletal traction should be utilized on all patients whose general physical condition does not permit operative intervention.     

Albumin obscures sex differences in blood protein patterns of rats and humans.

Sex related differences in the blood protein patterns of male and female rats and humans have been studied by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. In rats, a prominent band of mol.wt. 74000--78000 is seen in females in far greater quantity than in males, castrated males or ovariectomized females. A secondary band of 100000 is seen under non-reducing conditions in female rats that is absent in males. In humans, bands of 92000 and 88000 mol.wt. appear to be variable in concentration in men although relatively constant in women. The above differences are observable only if serum albumin is removed from the samples before electrophoresis. The results suggest that each sex has its own characteristic blood protein pattern.     

Involvement of the relA gene product and feedback inhibition in the regulation of DUP-N-acetylmuramyl-peptide synthesis in Escherichia coli.

The regulation of uridine diphosphate-N-acetylmuramyl-peptide (UDP-MurNAc-peptide) synthesis was studied by labeling Escherichia coli strains auxotrophic for lysine and diaminopimelate with [3H]diaminopimelate for 15 min under various conditions. The amounts of [3H]diaminopimelate incorporated into UDP-MurNAc-tripeptide and -pentapeptide by a stringent (rel+) strain were the same in the presence or absence of lysine. Chloramphenicol-treated rel+ cells showed a 2.8-fold increase in labeled UDP-MurNAc-pentapeptide. An isogenic relaxed (relA) strain deprived of lysine showed a 2.7-fold increase in UDP-MurNAc-pentapeptide. Thus, UDP-MurNAc-pentapeptide synthesis is regulated by the relA gene. D-Cycloserine treatment of rel+ and relA strains caused a depletion of intracellular UDP-MurNAc-pentapeptide. Labeled UDP-MurNAc-tripeptide accumulated in D-cycloserine-treated cells of the rel+ and relA strains, suggesting that UDP-MurNAc-pentapeptide is a feedback inhibitor of UDP-MurNAc-peptide synthesis. In lysine-deprived cells, D-cycloserine treatment caused 41- and 71-fold accumulations of UDP-MurNAc-tripeptide in rel+ and relA strains, respectively. A 124-fold increase in UDP-MurNAc-tripeptide occurred in lysine-deprived rel+ cells treated with both chloramphenicol and D-cycloserine. These results indicate that both the relA gene product and feedback inhibition are involved in regulating UDP-MurNAc-peptide synthesis during amino acid deprivation.     

Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis

The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment.     

Effect of amino acid deprivation and chloramphenicol treatment on cell sizes of rel+ and relA- strains of Escherichia coli.

The effects of inhibition of protein synthesis on the cell size distributions of rel+ and relA- derivatives of Escherichia coli K-12 were determined. Amino acid deprivation resulted in a reduction in the cell sizes of rel+ strains but not of relA- strains. Treatment with chloramphenicol (CAM) did not alter the size distributions of either rel+ or relA- strains except when they were rel+ dap-. CAM treatment of rel+ dap- strains resulted in an increase in cell size. It is proposed that these results reflect differences in the structures of the cell envelopes of rel+ and relA- bacteria.