Caution in the use of 2-iminothiolane (Traut's reagent) as a cross-linking agent for peptides. The formation of N -peptidyl-2-iminothiolanes with bombesin (BN) antagonist (d -Trp6 ,Leu13 -ψ[CH2 NH]-Phe14 )BN6−14 and d -Trp-Gln-Trp-NH2

During a study aimed at generating a bispecific molecule between BN antagonist (D-Trp(6),Leu(13)-psi[CH(2)NH]-Phe(14))BN(6-14) (Antag1) and mAb22 (anti-FcgammaRI), we attempted to cross-link the two molecules by introducing a thiol group into Antag1 via 2-iminothiolane (2-IT, Traut's reagent). We found that reaction of Antag1 with 2-IT, when observed using HPLC, affords two products, but that the later eluting peptide is rapidly transformed into the earlier eluting peptide. To understand what was occurring we synthesized a model peptide, D-Trp-Gln-Trp-NH(2) (TP1), the N-terminal tripeptide of Antag1. Reaction of TP1 with 2-IT for 5 min gave products 1a and 3a; the concentration of 1a decreased with reaction time, whereas that of 3a increased. Thiol 1a, the expected Traut product, was identified by collecting it in a vial containing N-methylmaleimide and then isolating the resultant Michael addition product 2a, which was confirmed by mass spectrometry. Thiol 1a is stable at acidic pH, but is unstable at pH 7.8, cyclizes and loses NH3 to give N-TP1-2-iminothiolane (3a), ES-MS (m/z) [602.1 (M+H)(+)], as well as regenerating TP1. Repeat reaction with Antag1 and 2-IT allowed us to isolate N-Antag1-2-iminothiolane (3b), FAB-MS (m/z) [1212.8 (M+H)(+)] and trap the normal Traut product 1b as its N-methylmaleimide Michael addition product 2b, ES-MS (m/z) [1340.8 (M+H)(+)]. Thiol 1b is also stable at acidic pH, but when neutralized is unstable and cyclizes, forming 3b and Antag1.

Interleukin-10 in the brain

Interleukin (IL)-10 is synthesized in the central nervous system (CNS) and acts to limit clinical symptoms of stroke, multiple sclerosis, Alzheimer's disease, meningitis, and the behavioral changes that occur during bacterial infections. Expression of IL-10 is elevated during the course of most major diseases in the CNS and promotes survival of neurons and all glial cells in the brain by blocking the effects of proapoptotic cytokines and by promoting expression of cell survival signals. Stimulation of IL-10 receptors regulates numerous life- or death-signaling pathways--including Jak1/Stat3, PI 3-kinase, MAPK, SOCS, and NF-kappaB--ultimately promoting cell survival by inhibiting both ligand- and mitochondrial-induced apoptotic pathways. IL-10 also limits inflammation in the brain; it does so by three major pathways: (1) reducing synthesis of proinflammatory cytokines, (2) suppressing cytokine receptor expression, and (3) inhibiting receptor activation. Finally, IL-10 induces anergy in brain-infiltrating T cells by inhibiting cell signaling through the costimulatory CD28-CD80/86 pathway. The multiple functions of IL-10 in the brain will create new and intriguing vistas that will promote a better understanding of neurodegenerative diseases. These discoveries could lead to development of innovative approaches for the use of antiinflammatory cytokines in major debilitating diseases of the CNS.

Correlation between mitochondrial membrane potential and neurotoxic effect of corticosterone on primary cultured hippocampal cells

Experiments were carried out to study the toxic effect of corticosterone (CORT) on primary cultured hippocampal cells and its relationship with mitochondrial membrane potential (MMP). Hippocampal cell survival and MMP were assessed by MTT and laser scanning confocal microscopy respectively. The results indicated that the survival rate of hippocampal neurons and astrocytes was dose dependently reduced in the hypoglycemic (3 5 mmol/L) and serum free medium for 24 h. With the same concentration of CORT, the toxic effect of CORT on hippocampal neurons was more serious than that on astrocytes. A supplement of high concentration of glucose (25 mmol/L) greatly improved the survival rate of hippocampal neurons cultured in the hypoglycemic and serum free medium. The disruption of MMP was induced by CORT (10( 6) mol/L) in hippocampal neurons cultured in hypoglycemic and serum free medium and antagonized by high concentration of glucose. It is therefore suggested that hippocampal neurons are more sensitive to the toxic effect of CORT in comparison with astrocytes. Neurotoxic effect of CORT can be reduced by high concentration of glucose. CORT-induced reduction of MMP may be one of the mechanisms for its neurotoxicity.

Properties of hybrid enzymes between Synechococcus large subunits and higher plant small subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase in Escherichia coli

To explore the function of small subunits of Rubisco, three hybrid enzymes were synthesized in Escherichia coli by construction of a transcriptionally coupled expression system in which the synthetic small subunit gene of rice, tobacco, and wheat, respectively, was cloned downstream from the large subunit gene of Synechococcus sp. PCC6301. These coexpression products were detected by utilizing SDS-PAGE and confirmed by immunoblotting. The amount of carboxylase activity from the intact cells revealed that each higher plant small subunit was able to assemble with the Synechococcus large subunit octamer core to form an active heterologous enzyme in E. coli. However, in these heterologous enzymes, the interaction between large subunits and small subunits was very weak, the small subunit readily dissociated from the large subunit octamer core. A detailed kinetic assay was carried out with the partially purified hybrid enzymes. Compared to Synechococcus Rubisco, the activity of rice, tobacco, and wheat hybrid Rubisco decreased to 37, 61, and 37% of the original activity, respectively. These hybrid enzymes showed a greater affinity for CO2 and RuBP than Synechococcus Rubisco. The specificity factor of the three hybrid Rubiscos was 98, 84, and 76%, respectively, of the original. These results indicate for the first time that the small subunit contributes to the stability, catalytic efficiency, and CO2/O2 specificity of Rubisco together, which suggests that small subunits may be fruitful targets for engineering an improved Rubisco. Meanwhile, we found that sorbitol in the culture of induced cells promoted the production of active assembled enzyme and shortened the time to reach maximal expression.

IL-10 inhibits apoptosis of promyeloid cells by activating insulin receptor substrate-2 and phosphatidylinositol 3'-kinase

IL-10 is well known to be a potent inhibitor of the synthesis of proinflammatory cytokines, but noninflammatory hemopoietic cells also express IL-10Rs. Here we show that IL-10 directly affects progenitor myeloid cells by protecting them from death following the removal of growth factors. Murine factor-dependent cell progenitors cultured in the absence of growth factors were 43 +/- 1% apoptotic after 12 h. Addition of IL-10 at a concentration as low as 100 pg/ml significantly reduced the apoptotic population to 32 +/- 3%. At 10 ng/ml, IL-10 caused a 4-fold reduction in the apoptotic population (11 +/- 1%). The anti-apoptotic activity of IL-10 was significantly inhibited with a neutralizing IL-10R Ab. Factor-dependent cell progenitor promyeloid cells expressed functional IL-10Rs, as assessed by precipitation of a 110-kDa protein with an Ab to the IL-10R and by the ability of IL-10 to activate Jak1 and Tyk2 and to phosphorylate tyrosine 705 on Stat-3. IL-10 increased tyrosyl phosphorylation of insulin receptor substrate-2 and stimulated the enzymatic activity of both phosphatidylinositol 3'-kinase and Akt. The anti-apoptotic activity of IL-10 was blocked by inhibition of phosphatidylinositol 3'-kinase. Wortmannin and LY294002 also totally inhibited activation of extracellular signal-related kinase (ERK)1/2 by IL-10. Direct inhibition of ERK1/2 with the mitogen-activated protein kinase/ERK kinase inhibitor PD98059 partially, but significantly, impaired the anti-apoptotic activity of IL-10. These data establish that activation of the IL-10R promotes survival of progenitor myeloid cells. This survival-promoting activity is totally due to IL-10 stimulating the insulin receptor substrate-2/PI 3-kinase/Akt pathway, which increases the anti-apoptotic activity of ERK1/2.

Susceptibility of nonpromoter CpG islands to de novo methylation in normal and neoplastic cells

BACKGROUND

Many cancers display alterations in methylation patterns of CpG islands--stretches of DNA rich in CpG dinucleotides often associated with gene promoters that are involved in initiation of gene transcription. This methylation may perturb expression of genes critical to the regulation of cell proliferation. Aberrant methylation is not limited to a few genes or to promoter regions but has been found on a genome-wide scale in a variety of neoplasias, including colorectal cancer and acute myelogenous leukemia. Our goal was to characterize, in a quantitative manner, the profiles of abnormally methylated genes that may be specific for different cancers.

METHODS

Using a quantitative assay, methylation-sensitive single nucleotide primer extension (MS-SNuPE), we have analyzed the methylation levels of promoter and exonic (coding region) CpG islands of two cyclin-dependent kinase inhibitors [p15(INK4B) and p16(INK4A)] and the PAX6 gene, which encodes a transcriptional factor involved in neuronal proliferation, in DNA samples taken from patients with chronic myelogenous leukemia, acute myelogenous leukemia, myelodysplastic syndrome, and colorectal cancer.

RESULTS

De novo methylation of all three exonic loci in tumors--relative to baseline levels found in nontumor tissue or blood--was observed in hematologic neoplasias and in solid tumors as well as in normal colonic tissue. However, methylation of promoter regions was more limited. Moreover, two different patterns of promoter methylation distinguished the leukemias from colorectal cancer: p15 promoter hypermethylation was found only in the leukemias, and p16 promoter hypermethylation occurred only in colon tumors. However, we did not address this issue prospectively; therefore, such an observation is only hypothesis generating.

CONCLUSIONS

The methylation patterns that we observed suggest that exonic CpG islands are more susceptible to de novo methylation than promoter islands and that methylation may be seeded in exonic regions, from which it can spread to other islands, including promoter regions. Subsequent selection of cells with a growth advantage conferred by spread of methylation into and inactivation of a particular promoter might then contribute to the genesis of a specific type of cancer.

Tumor necrosis factor(alpha) and insulin-like growth factor-I in the brain: is the whole greater than the sum of its parts?

The cytokine tumor necrosis factor(alpha) (TNFalpha) and the hormone insulin-like growth factor-I (IGF-I) have both been shown to regulate inflammatory events in the central nervous system (CNS). This review summarizes the seemingly independent roles of TNFalpha and IGF-I in promoting and inhibiting neurodegenerative diseases. We then offer evidence that the combined effects of IGF-I and TNFalpha on neuronal survival can be vastly different when both receptors are stimulated simultaneously, as is likely to occur in vivo. We propose the framework of a molecular model of hormone-cytokine receptor cross talk in which disparate cell surface receptors share intracellular substrates that regulate neuronal survival.

Cloning of bovine CD34 cDNA

CD34 is a leukocyte antigen that is expressed in various cell types including hematopoietic cells. Monoclonal antibodies against human, murine, and canine CD34 proteins have been used for the identification of lymphohematopoietic stem/progenitor cells. The cDNA encoding bovine CD34 was cloned, and its nucleotide sequence was determined. The identity of the deduced amino acid sequence of the encoded protein to those of human, murine. and canine CD34 proteins was 61.1%, 56.0%, and 66.1%, respectively. Northern blot hybridization with the cDNA as a probe detected CD34 RNA expression in the cerebrum, spleen, heart, and lung of a fetal calf.

Correlation of immunohistochemical molecular staging of bladder biopsies and radical cystectomy specimens

PURPOSE

To determine the relationship of p53, retinoblastoma (RB), and p16 expression between precystectomy transurethral resection bladder (TURB) biopsy and matched cystectomy specimens; and to determine the value of p53 immunoreactivity for predicting progression and survival in patients undergoing radical cystectomy.

METHODS AND MATERIALS

We performed p53 immunohistochemical staining on matched archival TURB and cystectomy specimens taken from 40 patients. Twenty-seven and 26 of these patients were also evaluated for RB and p16 expression, respectively.

RESULTS

Twenty-eight (70%) of the TURB and 22 (55%) of the cystectomy specimens stained positive for p53. RB and p16 protein expression were altered in 19 (70%) and 19 (73%) of the TURB specimens, respectively, and 19 (70%) and 19 (73%) of the cystectomy specimens, respectively. There was a strong correlation between p53, RB, and p16 expression and TURB and cystectomy specimens (all p < 0.001). In preoperative and postoperative multivariate analyses, biopsy p53 and cystectomy p53 were independently associated with disease progression (p = 0.049 and p = 0.034, respectively) and bladder cancer-related death (p = 0.044 and p = 0.037, respectively).

CONCLUSION

p53, RB, and p16 expression patterns on TURB specimens correlate with cystectomy specimens. p53 immunoreactivity is an independent predictor of disease progression and bladder cancer survival. These data support the potential of prognostic staging using immunohistochemical analysis on bladder biopsy specimens prior to neoadjuvant or definitive therapy.

Expression and distribution of the Kit receptor in bovine bone marrow cells

OBJECTIVE

To characterize the expression and distribution of the Kit receptor in bovine bone marrow cells (BMC) and to define the function of its ligand, stem cell factor (SCF).

ANIMALS

Six 7- to 70-day-old healthy male Holstein-Friesian calves.

PROCEDURES

Expression and distribution of the Kit receptor were assessed by use of flow cytometry with monoclonal antibodies (mAb) against the bovine Kit protein. Using Giemsa-stained centrifuged preparations, the histologic appearance of Kit receptor positive (Kit+) BMC were evaluated. Semisolid cultures supplemented with granulocyte colony-stimulating factor (G-CSF) and SCF were used to measure the colony formation capacity of Kit+ BMC.

RESULTS

The Kit receptor was expressed on approximately 18% of total BMC. Most of Kit+ BMC did not coexpress lineage markers, but a small subset of this population did coexpress CD3. The Kit+CD3- BMC were a heterogeneous cell population comprising blast-like cells such as myeloblasts, promyelocytes, rubriblasts, and prorubricytes. Conversely, Kit+CD3+ BMC had a lymphocyte-like appearance. Kit+ BMC formed colonies in semisolid culture with G-CSF, whereas Kit- BMC failed to grow. Addition of SCF to G-CSF resulted in superadditive enhancement in colony numbers and size.

CONCLUSIONS

The Kit receptor is expressed primarily on immature blood cells in bovine bone marrow, and Kit+ BMC contain hematopoietic progenitor cells that are reactive to G-CSF. In addition, SCF synergizes with G-CSF to stimulate colony formation by these cells. Our results suggest that the Kit receptor and its ligand, SCF, are involved in early stages of granulopoiesis in calves.

Characterization of a New Monoclonal Antibody 6G7 That Recognizes a Unique Antigen on Myeloid and Lymphoid Cells

We generated a monoclonal antibody (mAb) 6G7, which recognizes a 220-kD antigen on selected subpopulations of normal myeloid and lymphoid cells and their malignant counterparts. 6G7 reacts with 90-95% of peripheral blood B cells, 70-80% of CD8(+) cells, 30-35% of CD4(+) cells, 20-40% of monocytes, and 20-40% of CD34(+) cells from bone marrow. 6G7 reacts with leukemic blasts in acute myeloid leukemia (14/16), adult acute lymphoblastic leukemia (ALL) (5/5), pediatric ALL (5/9), chronic lymphocytic leukemia (8/8), follicular lymphoma (7/7), and Burkitt's lymphoma (1/1). Long-term bone marrow culture of 6G7(+/-) cells showed the majority of clonogenic hematopoietic cells were in mAb 6G7 subpopulation. An immunotoxin of 6G7 and ricin A chain was cytotoxic to 6G7(+) leukemia cell lines. mAb 6G7 has potential clinical applications for targeted immunotherapy of both leukemia and lymphoma.

[Study of sintering temperature of HN-97 porcelain stain]

OBJECTIVE

To determine the sintering temperature range and the best temperature of coloration of HN-97 porcelain stain,and matched porcelain powders.

METHODS

(1) The authors used prepared experiments of sintering temperatures and different sintering temperatures with different porcelain powders.

RESULTS

The results showed sintering temperature range of the stain was 820-955 degrees centigrade; (2)The stain can be matched with many porcelain powders (e.g.Vita,Densply. Shofu and Shanghai); (3)Surface of stain was smooth, colour was stable,integrate was good.

CONCLUSION

The stain can be used once coloration and glaze for restoration of porcelain, autoglazing temperature of which is between 820-955 degrees centigrade and the operation is easy.

[An preliminary comparative study on physiological activity of Fritillaria pallidiflora Schrek. and F. delavayi Franch]

OBJECTIVE

To compare the physiological activity of Fritillaria pallidiflora alkaloids(FPA) with that of F. delavayi alkaloids(FDA).

METHOD

Xylene-induced ear swelling in mice, SO2-induced cough in mice, expectorant experiment on phenolsulfon phthalein excretion and bacteria incubation in vitro, etc.

RESULT

The total alkaloids of both FPA and FDA(i.g., 400 mg.kg-1 and 200 mg.kg-1) have anti-inflammatory, antibechic and expectorant effects, but the former is more effective than the latter. Given the same dosage, FPA is still more effective than FDA. FPA can inhibit Hemophilus influenzae, Staphylococcus aureus and Streptococcus pneumoniae, etc, more effectively than FDA.

CONCLUSION

In anti-inflammatory, antibechic, expectorant and bacteriostatic effects FPA is superior to FDA.

Hydroxy-dibenzo crown ether stationary phase for capillary gas chromatography using sol-gel technology

A new kind of crown ether, OH-dibenzo-14-crown-4 (OH-DB14C4), is prepared and coated onto the fused silica capillary by sol-gel process. Chromatographic characteristics including column efficiency (> 3,000 plates/m), thermal stability (to 330 degrees C) and ability of deactivation are studied. The selectivity of new stationary phase is superior to sol-gel OH-terminal silicone oil (OH-TSO) for positional isomers of some aromatic compounds such as xylene, dichlorobenzene, nitrotoluene, nitrochlorobenzene. The new stationary phase has high sample capacity for separation of small molecular mass compounds: low-molecular-mass alcohols, ethers and ketones, short-chain fatty acids and volatile amines.

TabBO: a model reflecting common molecular features of androgen-independent prostate cancer

We established two human prostate cancer cell lines, MDA PCa 2a and MDA PCa 2b, the TabBO model system, that reflect common features of human androgen-independent prostate cancer that are not present in other model systems: bone origin, prostate-specific antigen production, androgen receptor expression, and androgen sensitivity. We therefore hypothesized that molecular pathways in our model system reflect common alterations responsible for the progression of a subset of human prostate cancer. Progression to androgen independence has been hypothesized to be largely associated with impairment of the regulation of cell growth or apoptosis of prostate cancer cells. Therefore, in this study, we examined molecular markers known or suspected to be important in prostate cancer progression and key regulators of cell growth and apoptosis: p53, p21WAF1/CIP1, Bcl-2, Bax, retinoblastoma (Rb), and p16INK4A/MITS1. We analyzed the expression of these markers in the cell lines, their tumor of origin, and tumors derived from the cell lines by s.c. inoculation into nude mice. DNA sequencing of the entire open reading frames of the p53 and p21 genes revealed no mutations. Additionally, accumulation of the p53 protein was not found by Western blot analysis, nor was overexpression of the Bcl-2 oncoprotein detected. Bax expression was detected in MDA PCa 2a cells, whereas it was absent in MDA PCa 2b. Rb and p16 protein expression was normal as measured by both Western blot and immunochemical analyses. Immunohistochemical studies of p53, p21, Bcl-2, and Rb in both samples from the original human cancer from which the lines were derived and mouse xenografts derived from the lines revealed similar levels of protein. These results are consistent with reports indicating that 40-50% of bone metastases of prostate cancer have wild-type p53, 50-70% do not overexpress the Bcl-2 protein, and mutations in the p21 gene are rare. Therefore, we conclude that MDA PCa 2a and MDA PCa 2b reflect molecular pathways in a common subset of human androgen-independent prostate cancer and that important molecular players in apoptosis (namely, p53 and Bcl-2) seem to be intact in this subset of androgen-independent prostate cancer. Understanding the signal-transduction pathways operating in these cell lines may help to identify therapeutic targets for prostate cancer.

Corticosterone impairs cultured hippocampal neurons and facilitates Ca2+ influx through voltage-dependent Ca2+ channel

AIM

To investigate the effect of corticosterone (Cor) on the viability of cultured hippocampal neurons as well as voltage-dependent Ca2+ channel (VDCC) on the membrane of the hippocampal neurons.

METHODS

The primary cultured hippocampal neurons were prepared and the viability of hippocampal neurons was determined by MTT assays. Inward Ca2+ currents of VDCC on the membrane of the hippocampal neurons were measured with the whole-cell patch-clamp technique.

RESULTS

Treatment with Cor concentration-dependently reduced the survival of hippocampal neurons. The IC50 of Cor was 3.2 mumol.L-1. Neurons from cerebral cortex were affected only by high concentrations of Cor (10 mumol.L-1 and 0.1 mmol.L-1) with the IC50, 85 mumol.L-1, 20 times larger than the former. Whole-cell patch-clamp experiment showed that Cor (1 mumol.L(-1)-0.1 mmol.L-1) sprayed to the surface of the hippocampal neurons instantly facilitated Ca2+ influx through VDCC with the maximal elevation of 53%, 191%, and 84% above the baseline respectively and this effect was shown to be concentration-independent. In addition, changing the membrane potentials from -40 mV to -10 mV did not affect the facilitating effect of Cor on the Ca2+ influx, indicating that Cor-induced Ca2+ influx was membrane potential-independent.

CONCLUSION

Cor markedly facilitated Ca2+ influx into the hippocampal neurons, which may be one of the important mechanisms underlying the neurotoxicity of Cor to hippocampus.

Expression of p16, Rb, and cyclin D1 gene products in oral and laryngeal squamous carcinoma: biological and clinical implications

Cyclin D1, p16, and Rb genes play a critical role in the regulation of the G1-S transition of the cell cycle and are frequently altered in several neoplastic entities. Analysis of the protein products of these genes by molecular and immunohistochemical methods provides information on their functional status and allows for the phenotypic evaluation of tumor cells. We performed Western blotting and immunohistochemical analysis on tissues from 35 primary oral and laryngeal squamous carcinoma specimens with previous molecular analysis of the p16 gene and correlated the results with relevant clinicopathologic factors. Our study shows significant concordance between Western blotting and immunostaining results for cyclin D1 (P = .01), p16 proteins (P = .01), and Rb (P = .04). Heterogeneous staining of tumor cells and the positivity of non-neoplastic host elements for Rb by immunohistochemistry contributed to the discrepancy noted in some tumors by Western blotting. Significant reciprocal relationship between p16 and Rb proteins was observed (P < .001); in most tumors, absence of p16 (89%) and detectable Rb (94%) proteins were found. Two tumors had negative cyclin D1 expression, and one third overexpressed this protein. There was a lack of correlation between cyclin D1 overexpression and the clinicopathologic factors studied. Our results indicate that the absence of p16 in most of these tumors may constitute an early tumorigenic event and that the loss of the Rb function plays a minor role in HNSC.

Elevated cyclin E levels, inactive retinoblastoma protein, and suppression of the p27(KIP1) inhibitor characterize early development of promyeloid cells into macrophages

Cyclin-dependent kinase inhibitors such as p27(KIP1) have recently been shown to lead to cellular differentiation by causing cell cycle arrest, but it is unknown whether similar events occur in differentiating promyeloid cells. Hematopoietic progenitor cells undergo lineage-restricted differentiation, which is accompanied by expression of distinct maturation markers. Here we show that the classical growth factor insulin-like growth factor I (IGF-I) potently promotes vitamin D(3)-induced macrophage differentiation of promyeloid cells, as assessed by measurement of a coordinate increase in expression of the integrin alpha subunit CD11b, the CD14 lipopolysaccharide receptor, and the macrophage-specific esterase, alpha-naphthyl acetate esterase, as early as 24 h following initiation of terminal differentiation. Addition of IGF-I to cells undergoing vitamin D(3)-induced differentiation also leads to an early increase in expression of cyclin E, phosphorylation of the retinoblastoma tumor suppressor protein, and a doubling of the cell number. Early expression of CD11b (24 h) is simultaneously accompanied by inhibition in the expression of p27(KIP1). Cell cycle analysis with propidium iodide revealed that CD11b expression at 24 h following initiation of differentiation occurs at all phases of the cell cycle instead of only those cells arrested in G(0)/G(1). Similarly, development of a novel double-labeling intra- and extracellular flow-cytometric technique demonstrated that single cells expressing the mature leukocyte differentiation antigen CD11b can also incorporate the thymidine analog bromodeoxyuridine. Likewise, expression of the intracellular DNA polymerase delta cofactor/proliferating-cell nuclear antigen at 24 h is also simultaneously expressed with the surface marker CD11b, indicating that these cells continue to proliferate early in their differentiation program. Finally, at 24 h following induction of differentiation, IGF-I promoted a fourfold increase in the uptake of [(3)H]thymidine by purified populations of CD11b-expressing cells. Taken together, these data demonstrate that the initial steps associated with terminal macrophage differentiation occur concomitantly with progression through the cell cycle and that these very early differentiation events do not require the accumulation of p27(KIP1).

Human blood dendritic cell-like B cells isolated by the 5G9 monoclonal antibody reactive with a novel 220-kDa antigen

We developed a murine IgG1 mAb, 5G9, following immunization of a BALB/c mouse with Daudi cells. By immunoprecipitation, 5G9 reacted with a 220-kDa Ag on Daudi cells, which reduced to four subunits (55, 65, 80, and 85 kDa). mAb 5G9 bound to 40-60% of peripheral blood B cells, weakly reacted with monocytes and granulocytes, and did not bind to erythrocytes, platelets, T cells, or NK cells. mAb 5G9 brightly stained scattered cells in human tonsil sections, which appeared to be dendritic cells (DC) by morphology. mAb 5G9 also stained scattered cells in cytospin slides of monocyte-derived DC with long, thin, beaded membrane processes, morphologically distinct from other monocyte-derived DC. Positive selection of blood mononuclear cells with mAb 5G9 and sheep anti-mouse IgG Dynabeads demonstrated an enriched population of DC. By flow cytometry analysis, these cells were CD19, CD20, CD22, CD40, CD44, CD83, CD86, IgD, and HLA-Dr positive and either kappa- or lambda-L chain positive. They did not express CD3, CD4, CD5, CD10, CD11b, CD13, CD25, CD56, CD14, CD33, or CD64. Isolated 5G9+ cells were potent APCs in allogeneic MLR, compared with 5G9- PBMC, 5G9- B cells, monocytes, and monocytes cultured in IL-4 and GM-CSF for 24 h. mAb 5G9 defines a novel peripheral blood cell with B cell phenotype and DC morphology and function: DC-like B cells. The significance of this cell in immune responses requires further study.

Production and characterization of monoclonal antibodies that recognize bovine Kit receptor

Kit receptor is a transmembrane tyrosine kinase that is the receptor for stem cell factor (SCF). The extracellular domain of bovine Kit receptor (boKit) was produced by a baculovirus expression system. Six monoclonal antibody (MAb) clones designated as bK-1 to bK-6 were obtained upon immunization of mice with the recombinant protein. Immunoprecipitation and flow cytometric analysis indicated that all of the MAbs specifically bound to boKit expressed in COS-7 cells transfected with boKit cDNA. Four of the six MAbs neutralized the biological activity of recombinant bovine SCF, whereas the other two did not. The boKit-positive and boKit-negative cell fractions were sorted from cryopreserved bovine bone marrow cells by the use of MAb bK-1. Colony formation assays indicated that the cells which were able to grow in response to bovine SCF were enriched in the boKit-positive fraction. These MAbs would be valuable in studying possible boKit-positive cell species such as bovine hematopoietic cells, and in defining the biological role of Kit receptor in cattle.

The effect of Epstein-Barr virus gene BHRF1 expression on radioresistance of nasopharyngeal carcinoma cells

In order to investigate the effect of the expression of Epstein-Barr virus gene BHRF1 on the apoptotic resistance of nasopharyngeal carcinoma cells to radiation, a highly expressing vector for BHRF1 was constructed and transfected into the nasopharyngeal carcinoma cell line CNE2. Then, the biologic alterations of the cells were tested after 60Co radiation. The results showed that, in the BHRF1-expressing cells, the apoptotic index was far lower than in the control groups after 60Co radiation, and cells recovered faster from the radiation, with a higher cell-proliferative rate, stronger ability of colony formation and tumor development in nude mice than that in the control groups. Given the functional homology of BHRF1 with bcl-2, our data indicate that BHRF1 expression could prohibit nasopharyngeal carcinoma cellular apoptosis caused by radiation and in this way contribute to oncogenic transformation.

Epstein-Barr virus BHRF1 prohibits the cells of nasopharyngeal carcinoma from apoptosis

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC). The BHRF1 EBV protein is expressed at high levels in productively infected cells and certain latently infected cells. In order to investigate the effect of expression of BHRF1 on the biological behaviour of NPC cells, we constructed the BHRF1 high expression vector and transfected it into the NPC cell line, CNE2. Then, the alteration of proliferation and apoptotic rates in the cells were tested before and after camptothecin treatment. After treatment by camptothecin, BHRF1-CNE2 cells could constantly and slowly proliferate and its apoptotic rate was less than in control groups, and the number of cells in the G phase decreased and in the S phase increased. So, it suggests that BHRF1 expression can enhance the resistibility of CNE2 cells to DNA-damaging agents that cause apoptosis.

[Determination of amoxicillin in human plasma by high performance liquid chromatography and its pharmacokinetics]

A rapid and sensitive assay for amoxicillin in human plasma has been developed using reversed phase high performance liquid chromatography. Plasma samples were prepared for analysis by addition of internal standard (tinidazole) followed by protein precipitation with HClO4. A YWG C18H37 column as stationary phase and a 0.033 mol.L-1 phosphate buffer (pH 7.2)--methanol mixture (85:15) as mobile phase were used with the UV detector set at 229 nm. The calibration curve was linear in the range from 0.2 microgram.ml-1 to 20.0 micrograms.ml-1 with gamma > 0.999. The analytical recovery of amoxicillin from plasma was > 86.7%. The relative standard deviations for within-day and between-day were < 5.48% and < 8.29%, respectively. Following oral administration of 500 mg in human volunteers, the peak levels of amoxicillin in plasma averaged 6.88 +/- 2.25 micrograms.ml-1 at 84.4 +/- 21.1 min. The mean half life time for amoxicillin was 62.8 +/- 14.6 min.

[Effect of microinjection of angiotensin II into area postrema on renal sodium excretion]

It has been known that area postrema (AP) possesses angiotensin II (A II) receptors and senses directly the change of blood A II level. The effect of microinjection of A II into the AP on renal sodium excretion was studied in the present investigation. Our experimental results show that microinjection of A II (2, 20 ng) increases GFR, RPF and UNaV (P < 0.05). These changes can be abolished by A II antagonist, saralatin and renal denervation (P < 0.05). However microinjection of A II (20 ng) into NTS produces no such changes. These results strongly suggest that the A II induced changes of renal hemodynamics and urine sodium excretion are mediated through AP.