Structure of the recoiling system in direct-photon and pi 0 production by pi - and p beams at 500 GeV/c.
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Journal Article↗
Biomedical subjects
G Wu
Publications and source records attributed to G Wu.
The cydD gene product, component of a heterodimeric ABC transporter, is required for assembly of periplasmic cytochrome c and of cytochrome bd in Escherichia coli.
The cydD gene of Escherichia coli encodes a protein which, together with the CydC protein, probably constitutes a heterodimeric, ABC-family membrane transporter, necessary for biosynthesis of the cytochrome bd quinol oxidase. Here, we demonstrate that a cydD mutant also fails to synthesise periplasmic c-type cytochrome(s), suggesting that the transporter exports haem or some other component involved in assembly of cytochromes that are found in, or exposed to, the periplasm. The CydDC system appears to be the first example of a transporter required for periplasmic cytochrome assembly processes requiring more than one type of haem. A mutant defective in trxB (adjacent to the cydDC operon, and encoding thioredoxin reductase) was unaffected in cytochrome c or bd assembly.
Adenosine Triphosphatases↗
Sequence of a cDNA encoding the p53 protein in rhesus monkey (Macaca mulatta).
A 2184-nucleotide (nt) sequence of the p53 gene in Rhesus monkey (Macaca mulatta) was determined in order to facilitate the use of the Rhesus as an animal model in the testing of novel antisense oligodeoxyribonucleotides for a variety of human cancers, including acute myelogenous leukemia (AML). Within overlapping regions, we found greater than 95% identity between the Rhesus and human p53 sequences, and greater than 98% identity between Rhesus and African green monkey p53 sequences. The deduced amino acid (aa) sequence of the p53 protein is highly conserved between human and Rhesus monkey, with only 18 minor differences in 393 aa.
Amino Acid Sequence↗
Effect of dimethylsulfoxide and hydroxyethyl starch in the preservation of fractionated human marrow cells.
Fractionated human bone marrow cells, isolated by density centrifugation, could be well cryopreserved in both a DMSO/HES/albumin mixture and the conventional cryoprotectant (DMSO/serum) with either a programmed freezer or a -80 degrees C freezer. A lower initial temperature rise and a delayed plateau phase in the mixture in comparison with those in the DMSO/serum were observed using a programmed procedure without heat fusion compensation. Plateau phase in the mixture could also be shortened with increased liquid nitrogen to minimize the transition phase duration. However, the method of mononuclear cells immersed in a -80 degrees C freezer and stored in liquid nitrogen is simple and easily standardized. Additionally, widely used lactated Ringer's solution instead of Normosol-R can be employed to prepare the mixture for the preservation of fractionated cells.
Albumins↗
Overexpression of human epidermal growth factor receptor and c-erbB-2 by neuroendocrine cells in normal prostatic tissue.
OBJECTIVE: It has been suggested that prostatic neuroendocrine (NE) cells play an important role in the growth and differentiation of the prostate by secreting various neuropeptides and serotonin. However, the mechanism by which NE cells themselves are regulated is virtually unknown. In the present study we evaluated the expression of the human epidermal growth factor receptor (EGFR) family (HER) in prostatic NE cells. METHODS: Formalin-fixed, paraffin-embedded tissue sections from twenty radical prostatectomy specimens were immunostained with validated rabbit polyclonal antibodies raised against human EGFR and c-erbB-2, using the streptavidin-peroxidase enzyme conjugate method. RESULTS: A strong immunoreactivity was observed with both antibodies in the cytosol of a few epithelial cells. These cells frequently had a dendritic appearance and were located in the acini and ducts. The EGFR-positive cells were predominant in most cases. Double immunostaining revealed the colocalization of both antigens with chromogranin A, a polypeptide that is expressed by most NE cells. Moreover, EGFR and c-erbB-2 appeared to be colocalized as well as independently expressed by different subpopulations of NE cells. CONCLUSIONS: The results suggest that prostatic NE cells might be regulated by the HER protein family, probably, in a ligand-specific fashion. This is the first report identifying a potential pathway regulating prostatic NE cells.
Amino Acid Sequence↗
Parathyroid hormone-related protein is expressed by prostatic neuroendocrine cells.
OBJECTIVE: Parathyroid hormone-related protein (PTHrP) is a regulatory peptide that has been associated with normal fetal growth and differentiation as well as the regulation of fetal calcium. In a variety of cancers, PTHrP has been implicated in the humoral hypercalcemia of malignancy. Recently, we demonstrated that all prostatic adenocarcinomas express PTHrP. In the present study, the localization of PTHrP and its mRNA in nonmalignant prostate tissue was assessed. METHODS: Formalin-fixed, paraffin-embedded prostatic tissues from 23 patients were evaluated. Immunocytochemistry (ICC) was performed by the streptavidin-peroxidase enzyme conjugate method using a monoclonal antibody, 8B12, generated against fragment 1-34 of the amino-terminal end of PTHrP. Nonradioactive in situ hybridization was carried out using a digoxigenin labeled single-stranded cDNA probe complementary to the sequence coding for PTHrP(15-120). RESULTS: PTHrP immunoreactivity was observed in the cytosol of a few epithelial cells. Double labeling and serial section ICC with 8B12 and a monoclonal antibody to chromogranin A (a generic neuroendocrine [NE] marker) revealed that PTHrP was present in a subpopulation of prostatic NE cells. In situ hybridization of mirror image sections demonstrated positive signals in prostatic NE cells in complete accordance with the ICC findings. CONCLUSIONS: The localization and production of PTHrP in prostatic NE cells suggest that this polypeptide may act in an endocrine-paracrine fashion involved in the prostatic growth and differentiation as well as the regulation of calcium in semen and seminal fluid.
Gene Expression↗
Parathyroid hormone-related protein: a potential autocrine growth regulator in human prostate cancer cell lines.
OBJECTIVE: We recently demonstrated that parathyroid hormone-related protein (PTHrP) is widely expressed by human prostate cancer tissue, suggesting that PTHrP might be involved in the growth and development of prostate cancer. To study this further, the production of PTHrP and its biologic effect were investigated using human prostate cancer cell lines. METHODS: The cell lines used were one androgen-dependent cell line, LNCaP, and two androgen-independent cell lines, PC-3 and DU-145. PTHrP secreted by cancer cells was measured by radioimmunoassay. The effect of PTHrP on DNA synthesis in these cells was determined by thymidine incorporation assay. RESULTS: All cell lines secreted immunodetectable levels of PTHrP in the culture-conditioned media. PC-3 cells secreted significantly higher amounts than the other two cell lines. A synthetic peptide, PTHrP(1-34), stimulated thymidine uptake in PC-3 and DU-145 cells more than threefold the control under serum-free and steroid-free conditions, whereas LNCaP was not affected. However, in the presence of dihydrotestosterone, DNA synthesis of LNCaP cells was stimulated by PTHrP in a dose-dependent manner. Additionally, this PTHrP-induced DNA synthesis was completely neutralized by a validated mouse monoclonal antibody (8B12) raised against PTHrP(1-34). CONCLUSIONS: Our data suggest that PTHrP may play a significant role in the growth of prostate cancer by acting locally in an autocrine fashion.
DNA, Neoplasm↗
Glutamine and glucose metabolism in intraepithelial lymphocytes from pre- and post-weaning pigs.
The metabolism of glutamine (Gln) and glucose was studied in intraepithelial lymphocytes (IEL) from 21-, 29- and 56-day-old pigs. Pigs were weaned at 21 days of age. Cells were incubated at 37 degrees C in the presence of Krebs-Ringer bicarbonate buffer (pH 7.4) containing 1 mM [U-14C]glutamine plus 5 mM glucose, or 5 mM [U-14C]glucose plus 1 mM glutamine. Glucose was converted to lactate, pyruvate and CO2, which accounted for 81, 11 and 8% of measured glucose carbon, respectively. Glutamine was metabolized mainly to glutamate (92% of Gln C) and ammonia, and to a lesser extent, to aspartate (4% of Gln C) and CO2 (4% of Gln C). In the presence of both glucose and glutamine, glucose provided 2-3-fold more ATP to IELs than glutamine in 21-56-day-old pigs, on the basis of their measured end products. The rates of ammonia and glutamate production from glutamine in IELs from 29-day-old pigs were 112 and 90% greater than those in cells from 56-day-old pigs, respectively. The rates of glucose oxidation to CO2 in IELs from 29-day-old pigs were elevated 56 and 64% respectively, compared with 21- and 56-day-old pigs. Elevated rates of substrate metabolism in IELs from 29-day-old post-weaning pigs indicated a metabolic alteration of these cells possibly due to changes in diet and intestinal bacterial population.
Adenosine Triphosphate↗
Optimization of subtractive hybridization in construction of subtractive cDNA libraries.
The efficiency of subtraction, integrity of residual single-stranded cDNA, and efficient recovery of nanogram quantities of double-stranded cDNA are the three most important factors affecting quality of subtractive hybridization reactions prior to subtractive cDNA library construction. Techniques for efficient isolation of single-stranded cDNA, after subtraction, have greatly improved from early protocols based on hydroxylapatite chromatography to phenol-chloroform extraction of biotin-streptavidin-crosslinked polynucleotides or oligo(dA)-cellulose affinity chromatography. Factors affecting mRNA stability at the hybridization step, however, also have consequences that directly affect the complexity of the library and the length of cDNAs recovered. We have optimized the subtractive hybridization step in subtractive cDNA library construction to ensure that single-stranded cDNAs survive hybridization as near to full length as possible. These improvements have enabled successful construction of subtractive cDNA libraries from the nanogram quantities of single-stranded cDNA remaining after extensive liquid hybridization to high calculated C(o)t values.
DNA, Complementary↗
Insulin stimulates glycolysis and pentose cycle activity in bovine microvascular endothelial cells.
Glucose metabolism via the pentose cycle, glycolysis and the Krebs cycle was quantified in bovine microvascular endothelial cells. The major measured end-product of glucose was L-lactate, with relatively small amounts of glucose carbons converted to CO2 and pyruvate. The pentose cycle accounted for less than 4% of the glucose utilized. About 60-70% of the metabolized glucose carbons could not be accounted for by lactate, pyruvate and CO2. Insulin stimulated glycolysis and pentose cycle activity, but had no effect on glucose oxidation via the Krebs cycle. As the pentose cycle is a major source of NADPH which is required for the synthesis of nitric oxide (the endothelium relaxing factor), insulin may play a role in regulating NO generation in endothelial cells by modulating the pentose cycle activity.
Animals↗
Gangliosides as modulators of neuronal calcium.
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Calcium↗
The uptake of glutamine and release of arginine, citrulline and proline by the small intestine of developing pigs.
Arteriovenous (A-V) differences in the plasma concentrations of amino acids across the jejunum were studied in preweaning (14- to 21-d-old) and post-weaning (29- to 58-d-old) pigs in the postabsorptive state. Glutamine was the only amino acid that was extracted by the small intestine in both pre- and post-weaning pigs. The production of citrulline by the jejunum was low in preweaning pigs, but was threefold greater in the post-weaning pigs than in the preweaning pigs. The output of proline by the intestine was observed in the post-weaning pigs but not in the preweaning pigs. Arginine and alanine were the predominant amino acids released by the jejunum of the pre- and post-weaning pigs, respectively. Whereas glutamate was the major amino acid formed from glutamine in pig enterocytes in vitro, the jejunum of the post-weaning pigs released comparable amounts of citrulline, proline and glutamate in vivo. There were no significant A-V differences in the concentrations of urea, ornithine, taurine, tyrosine, serine, glycine and nutritionally essential amino acids in either the preweaning or the post-weaning pigs. Thus, we demonstrated for the first time the uptake in vivo of glutamine and the release of arginine, alanine, citrulline, glutamate and proline by the small intestine of developing pigs. Our findings on the release in vivo of citrulline (the precursor of arginine) and proline by the small intestine of the pre- and post-weaning pigs provide a basis for explaining why arginine and proline are nutritionally essential amino acids for young suckling piglets but not for adult pigs.
Amino Acids↗
Dietary manganese deficiency decreases rat hepatic arginase activity.
This study was designed to quantify the effect of dietary manganese deficiency on rat hepatic Mn concentration and arginase activity. Weanling male Sprague-Dawley rats were randomly assigned to two groups of nine rats each and fed L-amino acid diets with 0 or 48 micrograms Mn/g diet for 21 d. After 21 d, hepatic Mn concentration (mumol/g liver dry wt, mean +/- SEM) was 0.130 +/- 0.005 for the control group but was lower (P < 0.01) in the Mn-deficient group (0.040 +/- 0.003). There were no differences in the hepatic concentrations of any other measured mineral. Hepatic arginase activity [mmol ornithine/(g hepatic protein.min)] was 1.55 +/- 0.22 in the control group and was lower (P < 0.01) in the Mn-deficient group (1.12 +/- 0.26). Plasma ammonia concentration was 301 +/- 6 mumol/L in the control group and was higher (P < 0.01) in the Mn-deficient group (480 +/- 8 mumol/L). In contrast, plasma urea concentration was higher (P < 0.01) in the control group (350 +/- 10 mumol/L) than in the Mn-deficient group (267 +/- 7 mumol/L). There were no differences in plasma concentrations of arginine or other amino acids between the control and the Mn-deficient groups. Our results demonstrate for the first time that dietary Mn deficiency results in altered plasma concentrations of ammonia and urea in association with decreased hepatic Mn concentration and arginase activity in young growing rats.
Amino Acids↗
Free and protein-bound amino acids in sow's colostrum and milk.
The changes in the concentrations of free and protein-bound amino acids in sow's colostrum and milk were quantified in this study. In sow's colostrum, taurine and histidine were the most abundant free amino acids (1 mmol/L of defatted milk). The concentrations of free histidine decreased, whereas those of other free amino acids increased, as lactation progressed. Milk free glutamine concentrations increased to the greatest extent among all free amino acids during the 29-d lactation period, and became the most abundant free amino acid in the milk (1.9 and 3.4 mmol/L of defatted milk) on d 22 and 29 of lactation. Sow's mature milk was rich in free taurine, glycine and glutamate (1-1.4 mmol/L of defatted milk). In contrast to free amino acids, the concentrations of milk protein and protein-bound amino acids decreased during the first 8 d of lactation and then leveled off. In colostrum and milk, glutamine plus glutamate were the most abundant protein-bound amino acids, whereas histidine and cystine were the least abundant. Leucine was the second and fourth most abundant protein-bound amino acid in colostrum and milk, respectively, with proline and lysine being the second most abundant ones on d 8 to 29 of lactation. Both colostrum and milk contained large amounts of urea (4.8-7.7 mmol/L of defatted milk) and ammonia (1.1-2 mmol/L of defatted milk), with ammonia concentration decreasing with advancing lactation stages in a pattern similar to that of milk protein. Thus, this study demonstrates the abundance of free glutamine, taurine, glycine and histidine in sow's milk relative to other free amino acids, as well as the changes in free and protein-bound amino acids in sow's milk during the 29-d lactation period. In light of the present findings, the nutritional importance of amino acids in milk for the growth and development of suckling piglets merits further studies.
Amino Acids↗
Inhibition by Guan-mu-tong (Caulis aristolochiae manshuriensis) of the growth of spontaneous mammary tumors in SHN virgin mice.
Multiparous SHN mice with spontaneous mammary tumors (5-10 mm in size) were given water extract of Guan-mu-tong (Gmt; Caulis aristolochiae manshuriensis) (0.5%) ad libitum as drinking water for 10 days. This treatment retarded significantly the growth of mammary tumors compared with the controls. By contrast, normal mammary gland growth, histology of adrenals and ovaries, and body weight were affected little by the Gmt treatment. Gmt appears to be the first agent inhibiting the growth of spontaneous mouse mammary tumors of palpable size by per os treatment.
Animals↗
Identification of a gene encoding a thioredoxin-like product necessary for cytochrome c biosynthesis and symbiotic nitrogen fixation in Rhizobium leguminosarum.
A Tn5-induced mutant of Rhizobium leguminosarum bv. viciae could not form nitrogen-fixing nodules on pea or vetch because of a lesion in electron transport to oxygen. The mutant lacked spectroscopically detectable cytochromes c and aa3. No proteins containing c-type cytochrome could be identified in the mutant by heme staining of proteins fractionated on polyacrylamide gels, indicating that the mutant was defective in maturation of all c-type cytochromes. The Tn5 mutation was determined to be located in a gene that was called cycY. The cycY gene product is homologous to the thioredoxin-like protein HelX involved in the assembly of c-type cytochromes in Rhodobacter capsulatus and to an open reading frame from a Bradyrhizobium japonicum gene cluster containing other genes involved in cytochrome c biogenesis. Our observations are consistent with CycY functioning as a thioredoxin that reduces cysteine residues in apocytochromes c before heme attachment.
Amino Acid Sequence↗
Enhanced metabolism of glucose and glutamine in mesenteric lymph node lymphocytes from spontaneously diabetic BB rats.
Increased energy substrate metabolism accompanies the functional activation of extrathymic immunocytes in the autoimmune BB diabetic rat, but the specific cells responsible have not been identified. To determine the possible contribution of lymphocytes to the elevated metabolism of glucose and glutamine, mesenteric lymph node cells were selected because they contain few macrophages or natural killer (NK) cells. Results from diabetic (BBd, n = 7) and non-diabetes-prone (BBn, n = 7) rats were compared with those from streptozotocin-induced diabetic (STZ-BBn, n = 6) rats. In BBd cells, all measured metabolites of glutamine (CO2, glutamate, aspartate, and NH3) in the presence of 5 mM glucose were elevated (1.5- to 2.5-fold) compared with BBn. In contrast, the only product of glucose metabolism (in the presence of 2 mM glutamine) that was increased was pyruvate (1.6-fold). All measured products of glucose metabolism were significantly lower in cells from STZ-BBn than from BBn rats. Products from glutamine did not differ. Calculated potential ATP production was greater (p < 0.05) in BBd than in BBn and STZ-BBn cells (86 +/- 5 vs. 65 +/- 2 and 53 +/- 5 nmol.2 h-1 x 10(-6) cells, respectively). However, in BBn and STZ-BBn rats, about three quarters of the cells were T (CD5+) cells and one quarter were B (MARK-1+) cells, whereas in BBd three quarters of the cells were MARK-1+.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine Triphosphate↗
Impact of annual screening and chemotherapy with praziquantel on schistosomiasis japonica on Jishan Island, People's Republic of China.
The impact of annual screening and treatment with praziquantel on schistosomiasis japonica was examined on Jishan Island in Po Yang Lake, Jiangxi Province. China. Prevalence of infection in the community decreased from 39% in year 1 to 33% in year 3 with a corresponding decrease in the geometric mean egg count from 51 eggs per gram of stool (epg) to 31 epg. The most dramatic changes in infection status and intensity of infection were observed in younger individuals (0-19 years of age). The prevalence of hepatosplenomegaly also significantly decreased, again primarily in younger individuals. No change in the community prevalence of schistosome-induced hepatic fibrosis was observed as determined by ultrasonography. Longitudinal cohort analysis, however, demonstrated significant improvement in treated individuals with advanced hepatic fibrosis. These data indicate that annual screening and treatment had a significant impact on infection status and morbidity and suggest that community therapy may be an effective approach to control schistosomiasis japonica in lake regions and marshlands in China. Further studies are necessary to determine the optimal and most cost-effective approach for drug delivery.
Adolescent↗