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Biomedical subjects

B J Wu

Publications and source records attributed to B J Wu.

35 records · Page 2Linked to original sources
PubMed1988

Wounding properties of steel pellets with different velocities and quality on soft tissue of dogs.

The characteristics of the soft-tissue wounds of the hind legs of 155 dogs produced by stainless steel spheres with four different masses and at various impact velocities were observed. It was found that when the mass of the spheres was identical, the velocity became the main factor to determine the severity of the damage; when the mass of the spheres was different but their kinetic energy was similar, then a smaller but faster sphere produced more severe damage than a larger but slower one. Shallow but wide and severe wounds usually resulted. The rate of disability of extremities with such wounds was very high. These wounding properties of steel spheres have caused some new problems in the treatment of war injuries.

Animals↗
PubMed1987

Chromosomal location of human genes encoding major heat-shock protein HSP70.

The HSP70 family of heat-shock proteins constitutes the major proteins synthesized in response to elevated temperatures and other forms of stress. In eukaryotes members of the HSP70 family also include a protein similar if not identical to bovine brain uncoating ATPase and glucose-regulated proteins. An intriguing relation has been established between expression of heat-shock proteins and transformation in mammalian cells. Elevated levels of HSP70 are found in some transformed cell lines, and viral and cellular gene products that are capable of transforming cells in vitro can also stimulate transcription of HSP70 genes. To determine the organization of this complex multigene family in the human genome, we used complementary approaches: Southern analysis and protein gels of Chinese hamster-human somatic cell hybrids, and in situ hybridization to human chromosomes. We demonstrate that functional genes encoding HSP70 proteins map to human chromosomes 6, 14, 21, and at least one other chromosome.

Animals↗
PubMed1987

Detection of three protein binding sites in the serum-regulated promoter of the human gene encoding the 70-kDa heat shock protein.

The basal promoter of the human gene encoding 70-kDa heat shock protein (HSP70) controls maximal transcriptional activity and serum-regulated expression. We demonstrate that the three promoter elements defined by in vivo studies--CCAAT, serum-regulated element (SRE), and "TATA"--correspond to protein-binding sites in vitro. The promoter interactions with protein factors in HeLa cell crude nuclear extracts were detected by an exonuclease III digestion assay. The sequence specificity was demonstrated with promoter probes containing wild-type sequences or unique linker-scanner mutations that alter each of the elements. We suggest that the protein factor binding to the SRE is involved in the serum-regulated expression of the human gene for HSP70.

Base Sequence↗
PubMed1986

Human HSP70 promoter contains at least two distinct regulatory domains.

The expression of the human HSP70 gene is induced by a wide range of physiological stresses, including exposure to heat shock and heavy metals, or under nonstress conditions, such as in response to serum stimulation. We have previously demonstrated that in either case the regulated expression is at the primary level of transcription. To determine whether transcription is mediated through a single or multiple genetic elements, we have dissected the sequences upstream of the transcription start site of the human HSP70 gene by constructing chimeric genes retaining variable amounts of 5' flanking regions fused to the bacterial gene encoding chloramphenicol acetyltransferase. Transcription from the chimeric genes was determined by S1 nuclease analysis of separate stable transfectants. The sequences required for heat shock and cadmium induction lie between -107 and -68. Within this region is the sequence CTGGAATATTCCCG, which is identical in 12/14 positions with the heat shock element of Drosophila heat shock genes, and a separate sequence, CGNCCCGG, which is homologous to the core of the human metallothionein II metal-responsive element. The sequences required for serum-stimulated transcription are distinct from the heat shock element. The sequence CCAAT at -68 is required for high levels of correctly initiated transcripts, and a purine-rich sequence, GAAGGGAAAAG, at -58 is required for serum stimulation. The human HSP70 promoter contains at least two regulatory domains--a distal domain responsive to heat shock or cadmium and a proximal domain responsive to stimulation by serum.

Base Sequence↗
PubMed1986

The E1A 13S product of adenovirus 5 activates transcription of the cellular human HSP70 gene.

Expression of the human gene encoding the major heat shock protein, HSP70, was induced during cell growth by serum stimulation and after infection with adenovirus 5. In this study we showed that HSP70 gene expression could be induced by adenovirus 5 infection, even in the absence of exogenous serum factors. Whereas serum stimulation induced the expression of the endogenous HSP70 gene, it had no effect on early adenovirus promoters. However, expression of both the cellular HSP70 gene and the adenovirus E3 promoter were activated during adenovirus infection. By using a collection of reconstructed mutant viruses, we identified the 13S product of the E1A region as the specific transcriptional trans-activator of the HSP70 gene.

Adenoviruses, Human↗
PubMed1985

Transcription of the human hsp70 gene is induced by serum stimulation.

We have examined the expression of the heat shock protein (hsp70) gene in human cells. The transcription of the hsp70 gene and accumulation of cytoplasmic hsp70 mRNA is induced by serum stimulation. Populations of HeLa cells and human embryonic kidney cells (cell line 293) were serum starved. Upon serum stimulation, the level of hsp70 mRNA transiently increases between 12 and 18 hr to a 10-fold higher level. The increased levels of hsp70 mRNA can be accounted for by a 10- to 15-fold increase in the rate of transcription of the hsp70 gene. When cells were serum-stimulated in the presence of an inhibitor of DNA synthesis, 1-beta-D-arabinofuranosylcytosine (araC), the levels of hsp70 mRNA were induced to only 20% of the maximal level detected in the absence of the inhibitor. This suggests that the expression of the hsp70 gene is coupled to DNA synthesis. The cloned human hsp70 gene contains regulatory sequences that confer serum-stimulated transcriptional control. The endogenous hsp70 gene and the transfected chimeric gene containing sequences upstream of the hsp70 gene fused to bacterial chloramphenicol acetyltransferase are both temporally expressed in stable transfectants of cell line 293 cells. The endogenous hsp70 mRNA and the chimeric mRNA reach maximum levels 12-18 hr after serum stimulation.

Blood↗
PubMed1984

Selective medium for Pseudomonas cepacia containing 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan and polymyxin B sulfate.

Contamination of solutions and lotions with Pseudomonas cepacia is a growing concern among health professionals. The identification of P. cepacia usually requires a long series of biochemical tests. In an effort to develop a more direct method, we evaluated plate count agar containing 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan and polymyxin B sulfate at respective concentrations of 1 and 75 micrograms/ml as a medium for selectively isolating P. cepacia. The medium inhibited the growth of all gram-negative bacilli and gram-positive cocci tested except P. cepacia and Serratia marcescens. These two microorganisms could easily be differentiated by their colony morphology and their reactions in the oxidase test. When nonsterilized water samples were inoculated with P. cepacia and spread or streaked on the selective medium, all P. cepacia organisms were recovered. These results demonstrate the usefulness of 9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan and polymyxin B sulfate in the detection of P. cepacia. We believe that this selective medium could be useful in isolating P. cepacia from mixed bacterial flora that might be present in environmental water and water-related samples, such as solutions and lotions.

Acridines↗
PubMed1982

Wounding effects of two types of bullets on soft tissue of dogs.

The wounding effects of 5.56 and 7.62 mm calibre bullets, hitting on soft tissues of 130 dogs at various velocities ranging from 513 to 933 m/s have been studied. The injury caused by 5.56 mm bullet was more severe than that caused by 7.62 mm bullet. This is due to the difference in ballistic behavior between the two types of bullets. The wound caused by 5.56 mm bullet was characterized by a trumpet-shaped channel with large defect. The skin around the exit was torn away and its shape was irregular, which, however, occurred only when the tumbling and the breaking of the bullet existed. High-speed X-ray photograph demonstrated that in 5.56 mm bullet group, temporary cavity was much larger and lasted longer. Splashing phenomenon could be seen at the exist and the fragments of the bullet could be found somewhere. Based on the comparisons the amount of absorbed energy, the volume of wound channel, the frequency of developing complex wound and the ratio of dimensions between the entrance and the exit, it proved that the injury caused by 5.56 mm bullet was several to dozens of time as severe as that caused by 7.62 mm bullet. Nevertheless, wound extents by both types of bullet would be similar if the inflicting bullet did not show any significant tumbling, breaking or deformation.

Animals↗
PubMed1974

Biochemical properties of Escherichia coli low-molecular-weight, heat-stable enterotoxin.

The low-molecular-weight, heat-stable type of Escherichia coli enterotoxin (ST) was obtained from sterile syncase broth filtrates of human and animal enteropathogenic E. coli strains. ST was assayed in infant mice, and it was found that this assay was specific for ST in that the high-molecular-weight, heat-labile type of E. coli exterotoxin would not cause fluid accumulation in these animals. ST was first detected in the broth of a culture of human strain 334A(015:H11) 5 h after inoculation, immediately after the log phase of growth; the highest concentration of ST occurred at 24 h after inoculation. ST was purified 13-fold by ultrafiltration and gel filtration chromatography. The purest preparation contained 15% protein and 2% carbohydrate. The mean effective dose or 1 unit dose in infant mice was 5.0 mug/mouse. The ST molecular weight was between 1,000 and 10,000, and its activity was resistant to acid, trypsin, and Pronase.

Animals↗
PubMed1973

Properties of the enterotoxic component in Escherichia coli enteropathogenic for swine.

The enterotoxic component in sterile syncase broth filtrates of Escherichia coli strains 340 (O9:K.:NM) and P307 (O8:K87,88a,b:H19) was studied. The enterotoxic activity in both strains was retained by an ultrafiltration membrane with a molecular weight retention of 100,000 (XM-100A) and eluted from a Sephadex G-200 column in the void volume. The enterotoxic activity in strain 340 was resistant to heating at 75 C for 30 min, but the activity in strain P307 was destroyed by heating at 60 C for 30 min. The P307 Sephadex G-200 column eluate possessing the enterotoxic activity, when desalted, contained 45.8% carbohydrate and 9.3% protein, and had an ED(50) of 2.2 mg/rabbit ileal loop. Immunodiffusion studies showed that this material contained both endotoxin and acid-polysaccharide capsular material. The enterotoxic activity was acidlabile and was destroyed by Pronase, but was resistant to trypsin and eluted as a single peak in the void volume of a 4% agarose column. The enterotoxic component could not be separated from the endotoxin; in fact, the data indicated that the two components are closely associated and that the enterotoxic activity resides in material of a protein nature.

Animals↗