MCP-1-stimulated monocyte attachment to laminin is mediated by beta 2-integrins

Migration of monocytes to sites of inflammation involves a series of attachments and detachments to extracellular matrix proteins. We examined the capacity of a chemokine, monocyte chemoattractant protein-1 (MCP-1), to regulate attachment of human monocytes to laminin, collagen I, collagen IV, or fibronectin. MCP-1 increased monocyte attachment to laminin in a dose- and time-dependent manner and stimulated a lesser increase to the other matrix proteins. Function-blocking monoclonal antibodies (MAbs) to the integrin beta 2-subunit (CD18), including Fab' fragments and alpha M (CD11b) blocked > 70% of attachment, whereas MAbs to the beta 1-integrin subunit reduced attachment by < 30%. This suggests that the CD11b/CD18 integrin is the predominant molecule involved in adhesion of MCP-1-stimulated monocytes to laminin. The association of CD11b with F-actin illustrated by confocal microscopy further supports this concept. In contrast, when monocytes were stimulated with the beta 1-stimulatory MAb TS2/16, monocyte adhesion to laminin occurred through beta 1-integrins. Thus MCP-1 can stimulate monocyte attachment to laminin, and this process is mediated through beta 2-integrins, principally CD11b/CD18.

Alternatively spliced mRNAs encoding soluble isoforms of the erythropoietin receptor in murine cell lines and bone marrow

32D Epo and 32D GM cells are subclones of the murine 32D cell line which are selectively dependent for proliferation and survival on erythropoietin (Epo) or granulocyte/macrophage colony-stimulating factor (GM-CSF), respectively. 32D GM cells were previously shown to express significant levels of the Epo receptor mRNA and protein which was retained intracellularly and did not appear on the cell surface. We have now analyzed the EpoR mRNA from the 32D GM line, using PCR followed by direct sequencing. Several alternatively spliced products were detected. In some molecules, intron 5 (I5) or part of I6 or both were retained. Retention of I5 results in a mRNA potentially encoding an almost complete extracellular domain, while retention of I6 gives rise to a mRNA encoding the complete extracellular and transmembrane domains. A different type of splicing results in the loss of exon 5 (E5), giving rise to a sequence encoding a truncated extracellular domain. These alternatively spliced sequences are differentially represented in 32D Epo versus 32D GM cells. All are additionally present in normal bone marrow cells. Apart from these alternatively spliced EpoR RNAs, no other abnormalities were detected in EpoR RNA from 32D GM cells that could account for the intracellular retention of EpoR in the non-erythroid subclones of 32D.

Regulation of human DNA polymerase delta during the cell cycle

The expression of polymerase delta (pol delta) during the cell cycle was studied in Molt 4 cells separated by counter-flow centrifugal elutriation. Northern blotting showed that pol delta mRNA levels increased by 3-fold at the G1/S border. Levels of pol delta protein determined by Western blotting also peaked at the G1/S border with qualitatively similar changes as the mRNA levels. Thus, pol delta gene expression appears to be regulated during the cell cycle at the transcriptional level. The mRNA half-life for pol delta was determined to be about 8 h and the protein half-life about 10 h. Parallel examination of the expression of proliferating cell nuclear antigen showed that the mRNA levels also increased about 2-fold at the G1/S border, while the protein levels of proliferating cell nuclear antigen increased steadily through the whole cell cycle period, and remained high at G2/M. Analysis of pol alpha expression showed qualitatively similar behavior as pol delta, but the magnitude of the changes were higher. Pulse labeling of cells metabolically arrested in G1,S, or G2/M with 32Pi showed that pol delta is a phosphoprotein and that it is most actively phosphorylated during the S phase.

Chemical modification of the hydroxylase of soluble methane monooxygenase gives one form of the protein with significantly increased thermostability and another that functions well in organic solvents

Proteolysis of the hydroxylase component of soluble methane monooxygenase (MMO) with trypsin yielded a protein which retained 50% activity in a standard MMO assay. In an H2O2-driven assay, in which H2O2 replaced two of the protein components, NADH and O2 used in the standard assay, the proteolysed hydroxylase retained full activity for ethane, propane and propene, but had a 2-3-fold increase with methane as substrate. Several crosslinking reagents have been tested for their ability to stabilise the proteolysed form of the hydroxylase. Using polyoxyethylene bis(imidazolyl carbonyl) (M(r) 3350) as the crosslinking agent, increased thermostability of the hydroxylase was observed. Activated methoxypolyethylene glycol (M(r) 5000) was used to modify the hydroxylase which was now soluble in organic solvents as well as water and could be activated by H2O2. The glycol-modified hydroxylase functioned well in organic solvents in the catalysis of propene oxidation.

A study on superoxide dismutase activity of some model compounds

The synthesis and characteristics of a binuclear ligand N,N,N',N'-tetrakis (2'-benzimidazolyl methyl)-1,4-diethylene amino glycol ether (EGTB) and its series of coordination compounds containing copper(II), iron(III), and manganese(II) with and without exogenous bridging ligand which was imidazolate ion (Im-), bipyridine (bpy), or 1,10-phenanthroline (phen) are reported. Depending on the redox potentials by cyclic voltammetry, the coordination compounds can act as catalysts for the dismutation of superoxide radicals (O2-). The detection of the rate constant of the reaction of superoxide ion with nitroblue tetrazolium (NBT) which is inhibited by superoxide dismutase (SOD) and its model compounds of the EGTB system has been performed by a modified illumination method. The rate constants kQ of the catalytic dismutation have been obtained.

Molecular determinants of bioactivity of the Saccharomyces cerevisiae lipopeptide mating pheromone

The a-factor of Saccharomyces cerevisiae (YIIKGVF-WDPAC(Farnesyl)-OCH3) is a peptide pheromone in which post-translational modification with a farnesyl isoprenoid and carboxyl methyl group is required for export and bioactivity. Truncated and carboxyl-terminal modified analogs of the a-factor were synthesized in order to determine the effect of such modifications on bioactivity. Bioactivity studies on carboxyl-terminal analogs in which the chirality, the cysteine thioether, and the carboxyl ester were varied in an attempt to study the influence of topology on a-factor activity indicate that the hydrophobicity conferred by the farnesyl moiety and not its specific spatial orientation is a key determinant of a-factor potency. Analyses on truncated a-factors suggest that sequential removal of NH2-terminal residues leads to a gradient of potency loss, with some amino acids exhibiting a slightly greater contribution to bioactivity than others. Random oligonucleotide-targeted mutagenesis of the gene encoding a-factor was coupled to a biological screen to identify altered a-factor peptides which are secreted yet exhibit a loss of a-factor bioactivity. Transformants exhibiting this phenotype were examined to identify codon changes presumably responsible for the altered phenotype, thus indicating residues that may contribute significantly to a-factor bioactivity.

[Case-control study on intrauterine growth retardation and vitamin nutritional status in late pregnancy]

Ninety-seven cases of pregnant women with intrauterine growth retardation (IUGR) and 133 controls were investigated on their dietary intake and blood vitamin levels in late pregnancy. Results showed insufficient calorie and protein intake, deficiency in calcium and vitamin B2, and low intake of vitamins A and B1 in pregnant women with IUGR. Their serum level of vitamin E was only half as that in controls (P < 0.01). Mothers' serum level of vitamin E correlated positively to several indicators reflecting infant growth with multiple stepwise regression analysis. There was no significant difference of activity of erythrocytic transketonas activity (TPP%) and activity coefficient (AC) of glutathione reductase between the two groups. It suggested pregnant women in both groups suffered from deficiency in thiamine and riboflavin (TPP% > 16%, AC > 1.2).

Methane to Ethylene with 85 Percent Yield in a Gas Recycle Electrocatalytic Reactor-Separator

Methane was oxidatively coupled to ethylene with an ethylene yield up to 85 percent and a total C(2) hydrocarbon yield up to 88 percent in a gas recycle high-temperature (800 degrees C) electrocatalytic or catalytic reactor where the recycled gas passes continuously through a molecular sieve trap in the recycle loop. Oxygen is supplied either electrocatalytically by means of the solid electrolyte support of the silver-based catalyst or in the gas phase. The C(2) products are obtained by subsequent heating of the molecular sieve trap. The selectivity to ethylene is up to 88 percent for methane conversion up to 97 percent.

Long-term effect of omega-3 fatty acid supplementation in active rheumatoid arthritis. A 12-month, double-blind, controlled study

OBJECTIVE

To study the long-term effects of supplementation with omega-3 fatty acids (omega 3) in patients with active rheumatoid arthritis.

METHODS

Ninety patients were enrolled in a 12-month, double-blind, randomized study comparing daily supplementations with either 2.6 gm of omega 3, or 1.3 gm of omega 3 + 3 gm of olive oil, or 6 gm of olive oil.

RESULTS

Significant improvement in the patient's global evaluation and in the physician's assessment of pain was observed only in those taking 2.6 gm/day of omega 3. The proportions of patients who improved and of those who were able to reduce their concomitant antirheumatic medications were significantly greater with 2.6 gm/day of omega 3.

CONCLUSION

Daily supplementation with 2.6 gm of omega 3 results in significant clinical benefit and may reduce the need for concomitant antirheumatic medication.

DNA polymerase delta is involved in the cellular response to UV damage in human cells

We have used antibodies specific for either polymerase delta (pol delta) or its accessory protein, proliferating cell nuclear antigen (PCNA), to demonstrate that they can markedly inhibit the capacity of HeLa nuclear extracts to effect repair of UV-damaged plasmid DNA. This provides the first unambiguous evidence for the involvement of pol delta in DNA repair synthesis. The mRNA levels of both pol delta and PCNA were significantly stimulated subsequent to UV irradiation of cultured cells, providing the first evidence that the cellular response to UV damage may involve regulation of pol delta and PCNA at the gene level. Thus, DNA polymerase delta and its accessory proteins, in addition to their function in replicative DNA synthesis, also function in DNA repair synthesis.

Identification of yeast component A: reconstitution of the geranylgeranyltransferase that modifies Ypt1p and Sec4p

Members of a large family of small GTP-binding proteins, termed Rabs in mammalian cells or Ypt and Sec4 in yeast, regulate vesicular traffic in all eukaryotic cells. These proteins are able to bind to membranes because they are modified by the type II geranylgeranyltransferase (GGTase-II), a multisubunit complex. Component A, encoded by the choroideremia gene in humans, is an escort protein that brings Rabs to component B, the catalytic alpha/beta heterodimer. Mutations in the catalytic subunits of the yeast GGTase-II (Bet2p/Mad2p) disrupt the membrane attachment of Ypt1p and Sec4p and this in turn blocks membrane traffic. In mammalian cells, deletions in choroideremia lead only to retinal degeneration, even though GGTase-II activity is defective. The yeast MRS6 gene encodes a protein that is approximately 30% identical to the choroideremia gene product. Here we show that the addition of recombinant Mrs6p to bacterially expressed Bet2p (beta subunit) and Mad2p (alpha subunit) reconstitutes GGTase-II activity in vitro, demonstrating that Mrs6p is yeast component A. Like Bet2p and Mad2p, Mrs6p is required for the membrane attachment of Ypt1p and Sec4p in vivo. In contrast to what has been observed before for the loss of function of the choroideremia gene, the depletion of Mrs6p from yeast cells blocks vesicular transport. Thus, these findings suggest that there is one essential escort protein in yeast, while more than one may exist in mammalian cells.

Selective inability of LPS-activated B lymphocytes to produce antibodies against autologous and allogeneic MHC class I antigens

Lipopolysaccharide (LPS)-activated B lymphocytes have been found to produce autoantibodies of a variety of specificities. We found that LPS-induced autoantibodies did not include antibodies against self H-2 class I antigens, suggesting a selective tolerance induction against some, but not other, autoantigens. However, LPS-activated B lymphocytes not only failed to produce antibodies against autologous H-2 class I antigens, but also against allogeneic H-2 class I antigens, suggesting a selective regulation of B cells to synthesize antibodies directed against autologous and allogeneic major histocompatibility complex antigens.

[Establishment of a human pancreatic adenocarcinoma cell line(JF305) with p53 expression]

A human pancreatic cancer cell line(JF305) was established from a pancreatic adenocarcinoma xenograft in nude mice. These cells have passed 103 passages in more than 1 year. The plating efficiency was 30.6%, and doubling time was 49.5 hours. Chromosomal analysis showed a human karyotype with a chromosome number between 66-130. JF305 cells exhibited epithelial morphologic features resembling the structure of the original tumor, and they grew to born tumor when inoculated again into nude mice. With immunohistochemical staining, the nuclei of JF305 cells were positive for p53. Therefore, JF305 offer a good model for the study of human pancreatic adenocarcinoma and P53 gene mutation.

Mabiosides C-E: triterpenoid saponins from the bark of Colubrina elliptica

Three novel saponins, mabiosides C-E, were isolated from the bark of Colubrina elliptica together with the known mabioside B and [alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->3)-alpha-L- arabinopyranosyl]-(1-->3)-jujubogenin. All the structures were established by spectroscopic methods.

Optoacoustic trace-gas monitoring with near-infrared diode lasers

An inexpensive resonant optoacoustic monitoring system using near-infrared laser diodes was developed. It was demonstrated that wavelength modulation at the resonance frequency of the cell provides a superior signal-to-noise ratio compared with amplitude modulation and eliminates background drifts and fluctuations. The system was tested out on ammonia. Its sensitivity is 8 parts in 10(9) (S/N = 1) at atmospheric pressure, which corresponds to a minimum detectable absorption coefficient of approximately 3.5 × 10(-11) cm(-1) W(-1). The pressure dependence of the optoacoustic resonance was also investigated. The monitor can be used as a continuous flow-through system up to a flow rate of approximately 3.5 L/min.

RNA polymerase binding using a strongly acidic hydrophobic-repeat region of sigma 54

sigma 54 is a rare bacterial protein that substitutes for sigma 70 in the case of Escherichia coli genes transcribed by certain activators with enhancer protein-like properties. It contains a strongly acidic region of previously unknown function. Gel mobility-shift assays using sigma 54 deletion mutants show that this region is essential for sigma 54 to bind the core RNA polymerase and recruit it to the promoter. Multiple-point mutational analysis shows that the acidic amino acids and overlapping periodic hydrophobic amino acids are necessary for this binding. Related sequences are not found within the core binding determinant of sigma 70, which binds the same core RNA polymerase. This comparison suggests that the core RNA polymerase interacts differently with the two sigma factors, likely contributing to the critical differences in transcription mechanism in the two cases.

Genetic study of indirect inguinal hernia

We performed a genetic analysis of 280 families with congenital indirect inguinal hernia ascertained in Shandong province. The multifactorial threshold model and segregation analysis were applied to these families to investigate the mode of inheritance of congenital indirect inguinal hernia. Our results indicate that congenital indirect inguinal hernia is not compatible with a multifactorial threshold model, and the frequent vertical transmission and high segregation ratio suggest autosomal dominant inheritance with incomplete penetrance and sex influence. Through further pedigree analysis of the multiple case families with at least two closely related affected members, we noted preferential paternal transmission of the disease gene, which might suggest the role of genomic imprinting in the aetiology of this condition.