[Effects of monoclonal antibodies to laminin receptors on the invasive and metastatic behaviors of human lung carcinoma cells]

The effects of laminin receptor monoclonal antibodies (McB1) on the cell growth, and the invasive and metastatic behaviors of human giant cell carcinoma (PG) as well as adenocarcinoma (PAa) of lung were investigated by using cell culture, modified microinvasion assay and experimental metastasis assay techniques. The results showed that McB1 could inhibit adhesion and spreading of PG and PAa cells on the laminin substrate. The monoclonal antibodies were able to induce alterations of the morphology and microtubule structure of the tumor cells. The growth and invasive abilities were inhibited, and the experimental metastasis of PG cells could be abolished by McB1. It is suggested that laminin receptors may play an important role in the process of tumor invasion and metastasis, and the related monoclonal antibodies may contribute to the therapy of tumor metastasis.

Influenza A virus haemagglutinin polymorphism: pleiotropic antigenic variants of A/Shanghai/11/87 (H3N2) virus selected as high yield reassortants

Genetic reassortment of the A/Shanghai/11/87 (H3N2) variant of influenza A virus with A/PR8/34 (H1N1) virus [the standard donor of high yield (hy) genes for influenza vaccine viruses] resulted in the isolation of two reassortants with differing H3 haemagglutinin (HA) phenotypes, X-99 and X-99a. The two HA phenotypes were derived from individual subpopulations of the H3N2 wild-type virus during the reassortment event. The HA mutants and their respectively derived reassortants (identical in RNA genotype) differed in antigenicity, replication characteristics, yield in chick embryos and haemagglutinin gene sequence. Despite antigenic differences in reactions to polyclonal rabbit antisera of 60%, both X-99 and X-99a, the hy reassortants, were equally immunogenic and protective in BALB/c mice to challenge by parental wild-type virus. Differences in HA phenotype were related to a Ser to Ile change at amino acid position 186. These findings emphasize the polymorphism of influenza virus strains as well as the need for caution in selection of vaccine strains from among antigenically distinct viral subpopulations.

Cloning and characterization of complementary DNA encoding the eukaryotic initiation factor 2-associated 67-kDa protein (p67)

The eukaryotic initiation factor 2 (eIF-2)-associated 67-kDa glycoprotein (p67) protects eIF-2 alpha-subunit from inhibitory phosphorylation by eIF-2 kinases, such as heme-regulated inhibitor and double-stranded RNA-activated inhibitor. This promotes protein synthesis in the presence of eIF-2 kinases present in animal cells (Ray, M. K., Datta, B., Chakraborty, A., Chattopadhyay, A., Meza-Keuthen, S., and Gupta, N. K. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 539-543). In this study, the primary structure of rat p67 is determined by cDNA cloning. Based on the partial amino acid sequences of overlapping tryptic and cyanogen bromide cleaved fragments, degenerate oligonucleotides were synthesized and used as primers for the polymerase chain reaction to amplify the corresponding p67 cDNA fragment from rat liver first strand cDNA. The amplified DNA was then used as a probe to screen a rat tumor hepatoma (KRC-7) cDNA library, and a positive clone covering the entire coding region was obtained. From the cDNA sequence, an open reading frame that encodes p67 as a 480-amino acid protein with a molecular mass of 53 kilodaltons was predicted for the unglycosylated protein. The cloned cDNA was further characterized by in vitro transcription-coupled translation in micrococcal nuclease-treated reticulocyte lysate. The translated product migrated similarly to p67 in SDS-polyacrylamide gel electrophoresis and was precipitated with antibodies against p67. Northern blot analysis of rat liver poly(A)+ RNA showed a single size class (approximately 2 kilobases) of mRNA. The deduced amino acid sequence of the protein showed a highly charged N-terminal region composed of two basic polylysine blocks and an acidic aspartic acid block. The protein also exhibits significant sequence identity in the N-terminal region with human eIF-2 beta-subunit.

Characteristics of the eukaryotic initiation factor 2 associated 67-kDa polypeptide

A eukaryotic initiation factor 2 (eIF-2) associated 67-kDa polypeptide (p67) protects the eIF-2 alpha-subunit from eIF-2 kinase(s) catalyzed phosphorylation, and this promotes protein synthesis in the presence of active eIF-2 kinase(s), [Datta, B., et al. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 3324-3328]. This report presents the results of studies related to characteristics of p67 action and the mechanism of p67:eIF-2 interaction: (1) p67 antibodies inhibited protein synthesis in hemin-supplemented rabbit reticulocyte lysates, and such inhibition was reversed by preincubation of the antibodies, specifically with p67. (2) p67 inhibited HRI- and dsI-catalyzed phosphorylations of the eIF-2 alpha-subunit and histones, but it did not inhibit casein kinase catalyzed phosphorylation of the eIF-2 beta-subunit. (3) p67 bound specifically to the eIF-2 gamma-subunit. p67 co-immunoprecipitated with the eIF-2 subunits when a p67/eIF-2 mixture was treated with p67 or eIF-2 subunit antibodies and protein A agarose. However, when eIF-2 was preincubated specifically with the eIF-2 gamma-subunit antibodies, subsequent co-immunoprecipitation of p67 with the eIF-2 subunits was completely inhibited. Similarly, preincubation of p67 and p67 antibodies prevented subsequent p67 binding to eIF-2. Preincubation of eIF-2, with either eIF-2 alpha- or beta-subunit antibodies, had no effect on p67 co-immunoprecipitation with the eIF-2 subunits. (4) p67:eIF-2 interaction is necessary for p67 activity to protect the eIF-2 alpha-subunit from eIF-2 kinase(s) catalyzed phosphorylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Tumor necrosis factor alpha as an autocrine and paracrine growth factor for ovarian cancer: monokine induction of tumor cell proliferation and tumor necrosis factor alpha expression

Ovarian tumor cells produce macrophage colony stimulating factor, a potent chemoattractant for monocytes. Monocytes and macrophages produce tumor necrosis factor alpha (TNF-alpha) and interleukin 1 alpha or interleukin 1 beta (IL-1 beta) that can stimulate ovarian tumor cell growth. The present study has explored whether paracrine stimulation by monocyte derived cytokines might induce autocrine growth stimulation of normal and malignant ovarian epithelial cells. Endogenous expression of TNF-alpha mRNA was detected in ascites ovarian cancer cells isolated directly from patients, but not in established cultures of normal or malignant ovarian epithelial cells. When ascites tumor cells were cultured for 7 days, TNF-alpha expression ceased but could be reinduced by treatment with TNF-alpha or IL-1 beta. Ascites fluid contained concentrations of the cytokines that could mediate these effects. Similarly, treatment of normal or malignant ovarian epithelial cells with purified recombinant IL-1 beta or TNF-alpha induced transcription of TNF-alpha mRNA within 1 h. TNF-alpha protein could be detected by enzyme-linked immunosorbent assay in conditioned medium from IL-1 beta treated ovarian cancer cells. [3H]thymidine incorporation by normal or malignant ovarian epithelial cells was stimulated by a 24-h incubation with IL-1 beta or TNF-alpha. Stimulation of proliferation by IL-1 beta could be partially blocked by an antibody against TNF-alpha or by soluble TNF-alpha-receptor. Thus, TNF-alpha may function as both an autocrine and a paracrine growth factor in ovarian cancer.

Use of bispecific heteroconjugated antibodies (anti-T cell antigen receptor x anti-MHC class II) to study activation of T cells with a full length or truncated antigen receptor zeta-chain

Ligand-induced activation of T cells involves recognition of monovalent peptide Ag complexed with a cell surface MHC-encoded molecule. In contrast, antibody-induced activation of T cells typically requires external cross-linking of the TCR. To examine the mechanisms that underlie the ability of these different stimuli to signal, we have created bispecific chimeric antibody molecules (BA) that mimic Ag in several important aspects. Anti-TCR-alpha, -beta, or anti-CD3-epsilon Fab fragments were covalently coupled to an anti-MHC class II Fab fragment. These BA elicited IL-2 production or proliferation from Ag-specific T cell hybridoma cells or splenic T cells, respectively, in the presence, but not the absence, of accessory cells expressing the appropriate MHC class II molecule. This response was prevented by soluble blocking antibodies against the TCR or MHC class II. When "presented" by MHC class II-bearing accessory cells, anti-TCR x anti-MHC class II BA, like cell surface Ag, elicited IL-2 production from T cell transfectants expressing full length TCR zeta-chain but not from otherwise identical cells expressing truncated zeta; when immobilized on a plastic surface these BA were potent stimulators that induced equal amounts of IL-2 from the same cells. Purified Ag/MHC complexes immobilized on plastic were able to induce IL-2 production from T cells expressing the full length, but not the truncated, form of zeta. We hypothesize that TCR-mediated T cell activation requires stable aggregation of the TCR. In this model, activation by mobile cell surface Ag/MHC or BA occurs in two steps, occupancy-induced TCR clustering followed by stable aggregation facilitated by the presence of a full length zeta-chain. Immobilized high affinity anti-TCR antibodies, but not low affinity Ag/MHC complexes, directly promote stable receptor aggregates, and thus would not require a full length zeta-chain.

Use of bispecific heteroconjugated antibodies (anti-T cell antigen receptor x anti-MHC class II) to study activation of T cells with a full length or truncated antigen receptor zeta-chain

Ligand-induced activation of T cells involves recognition of monovalent peptide Ag complexed with a cell surface MHC-encoded molecule. In contrast, antibody-induced activation of T cells typically requires external cross-linking of the TCR. To examine the mechanisms that underlie the ability of these different stimuli to signal, we have created bispecific chimeric antibody molecules (BA) that mimic Ag in several important aspects. Anti-TCR-alpha, -beta, or anti-CD3-epsilon Fab fragments were covalently coupled to an anti-MHC class II Fab fragment. These BA elicited IL-2 production or proliferation from Ag-specific T cell hybridoma cells or splenic T cells, respectively, in the presence, but not the absence, of accessory cells expressing the appropriate MHC class II molecule. This response was prevented by soluble blocking antibodies against the TCR or MHC class II. When "presented" by MHC class II-bearing accessory cells, anti-TCR x anti-MHC class II BA, like cell surface Ag, elicited IL-2 production from T cell transfectants expressing full length TCR zeta-chain but not from otherwise identical cells expressing truncated zeta; when immobilized on a plastic surface these BA were potent stimulators that induced equal amounts of IL-2 from the same cells. Purified Ag/MHC complexes immobilized on plastic were able to induce IL-2 production from T cells expressing the full length, but not the truncated, form of zeta. We hypothesize that TCR-mediated T cell activation requires stable aggregation of the TCR. In this model, activation by mobile cell surface Ag/MHC or BA occurs in two steps, occupancy-induced TCR clustering followed by stable aggregation facilitated by the presence of a full length zeta-chain. Immobilized high affinity anti-TCR antibodies, but not low affinity Ag/MHC complexes, directly promote stable receptor aggregates, and thus would not require a full length zeta-chain.

Suppression of a cellular differentiation program by phorbol esters coincides with inhibition of binding of a cell-specific transcription factor (NF-E2) to an enhancer element required for expression of an erythroid-specific gene

Induction by hemin increases, while induction with 12-O-tetradecanoylphorbol-13-acetate (TPA) represses, erythroid-specific gene expression in the human cell line K562. We analyzed the effects of hemin or TPA induction on the binding and activity of transcription factors at a regulatory element found within the transcriptional regulatory sequences of many erythroid-specific genes. TPA induction increases the binding of ubiquitous AP-1 factors to this element. TPA induction inhibits the binding of the lineage limited transcription factor NF-E2 to this transcriptional control element. Hemin induction of K562 cells does not facilitate the binding of NF-E2 to its recognition site. Hemin induction appears to nonspecifically increase the expression of transiently transfected genes in K562 cells. Beyond this nonspecific increase in gene expression, hemin induction acts to increase the activity of the lineage limited transcription factor NF-E2. The divergent effects of hemin and TPA on gene expression in K562 cells are mediated, in part, by their contrasting effects on the transcription factor NF-E2.

Structure of Paramecium tetraurelia calmodulin at 1.8 A resolution

The crystal structure of calmodulin (CaM; M(r) 16,700, 148 residues) from the ciliated protozoan Paramecium tetraurelia (PCaM) has been determined and refined using 1.8 A resolution area detector data. The crystals are triclinic, space group P1, a = 29.66, b = 53.79, c = 25.49 A, alpha = 92.84, beta = 97.02, and gamma = 88.54 degrees with one molecule in the unit cell. Crystals of the mammalian CaM (MCaM; Babu et al., 1988) and Drosophila CaM (DCaM; Taylor et al., 1991) also belong to the same space group with very similar cell dimensions. All three CaMs have 148 residues, but there are 17 sequence changes between PCaM and MCaM and 16 changes between PCaM and DCaM. The initial difference in the molecular orientation between the PCaM and MCaM crystals was approximately 7 degrees as determined by the rotation function. The reoriented Paramecium model was extensively refitted using omit maps and refined using XPLOR. The R-value for 11,458 reflections with F > 3 sigma is 0.21, and the model consists of protein atoms for residues 4-147, 4 calcium ions, and 71 solvent molecules. The root mean square (rms) deviations in the bond lengths and bond angles in the model from ideal values are 0.016 A and 3 degrees, respectively. The molecular orientation of the final PCaM model differs from MCaM by only 1.7 degrees. The overall Paramecium CaM structure is very similar to the other calmodulin structures with a seven-turn long central helix connecting the two terminal domains, each containing two Ca-binding EF-hand motifs. The rms deviation in the backbone N, Ca, C, and O atoms between PCaM and MCaM is 0.52 A and between PCaM and DCaM is 0.85 A. The long central helix regions differ, where the B-factors are also high, particularly in PCaM and MCaM. Unlike the MCaM structure, with one kink at D80 in the middle of the linker region, and the DCaM structure, with two kinks at K75 and I85, in our PCaM structure there are no kinks in the helix; the distortion appears to be more gradually distributed over the entire helical region, which is bent with an apparent radius of curvature of 74.5(2) A. The different distortions in the central helical region probably arise from its inherent mobility.

A strain of urease negative Cryptococcus neoformans isolated from the environment in China

This is the first report of a strain of urease negative Cryptococcus neoformans isolated from the environment in China. The colonies of this isolate showed brown pigmentation on cornmeal agar with 300 micrograms/ml caffeic acid, but failed to hydrolyze urea. Microbiological identification and pathogenicity tests in mice confirmed this as a strain of C. neoformans. A similar strain had reportedly been isolated from an AIDS patient.

Pathophysiologic role of eicosanoids in mesangial cell immune injury

The pathophysiologic role of thromboxane and of arachidonate 5-lipoxygenation products in mediating changes in glomerular filtration rate (GFR) and renal blood flow (RBF) was investigated in a rat model of mesangial cell immune injury induced by a monoclonal antibody (ER4) directed against the mesangial cell membrane antigen, Thy 1. Following a single intravenous dose of the ER4 antibody acute decrements in GFR and RBF occurred at 1 h and were associated with enhanced glomerular leukocyte infiltration and synthesis of thromboxane A2, 12-HETE and LTB4. Pretreatment of animals with the thromboxane synthase inhibitor, Furegrelate, or the thromboxane receptor antagonist SQ-29,548 ameliorated or completely abolished the decrements in GFR and RBF without reducing glomerular leukocyte infiltration. Pretreatment with the arachidonate 5-lipoxygenase inhibitor MK-886 partially ameliorated the decrements in GFR and RBF, reduced the glomerular leukocyte infiltration and completely inhibited the glomerular LTB4 synthesis. Combined treatment with Furegrelate and MK-886 completely abolished the decrements in GFR and RBF as well as the glomerular synthesis of thromboxane, LTB4 and 12-HETE without altering glomerular leukocyte infiltration. These observations indicate that in mesangial cell immune injury thromboxane A2 and arachidonate 5-lipoxygenation products originating from infiltrating inflammatory cells mediate the decrements in GFR and RBF. Selective inhibition of these eicosanoids could be of benefit in clinical forms of mesangial nephritis.

Retroposition in a family of carcinoma-associated antigen genes

The gene encoding the carcinoma-associated antigen defined by the monoclonal antibody GA733 is a member of a family of at least two type I membrane proteins. This study describes the mechanism of evolution of the GA733-1 and GA733-2 genes. A full-length cDNA clone for GA733-1 was obtained by screening a human placental library with a genomic DNA probe. Comparative analysis of the cDNA sequence with the previously determined genomic sequence confirmed that GA733-1 is an intronless gene. The GA733-2 gene encoding the monoclonal antibody-defined antigen was molecularly cloned with a cDNA probe and partially sequenced. Comparison of GA733-2 gene sequences with the previously established cDNA sequence revealed that this gene consists of nine exons. The putative promoter regions of the GA733-1 and GA733-2 genes are unrelated. These findings suggest that the GA733-1 gene was formed by the retroposition of the GA733-2 gene via an mRNA intermediate. Prior to retroposition, the GA733-2 gene had been affected by exon shuffling. Analysis of GA733-2 exons revealed that many delineate structural motifs. The GA733-1 retroposon was localized either to chromosome region 1p32-1p31 or to 1p13-1q12, and the GA733-2 founder gene was localized to chromosome 4q.

Cell growth regulation in epithelial ovarian cancer

BACKGROUND

As in the case of other epithelial neoplasms, most ovarian cancers arise from single clones of cells that have undergone multiple genetic alterations. A comparison of normal and malignant ovarian epithelium has identified several differences in growth regulation by peptide growth factors, protooncogenes, and tumor suppressor genes.

METHODS

Recent articles and abstracts have been reviewed.

RESULTS

The malignant ovarian epithelial phenotype has been associated with (1) autocrine growth stimulation by transforming growth factor-alpha, (2) loss of autocrine growth inhibition by transforming growth factor-beta, (3) mutation or amplification of ras in 2-12% of cases, (4) amplification of myc in 23% of specimens, (5) expression of fms in 56% of cases with potential autocrine stimulation by macrophage colony stimulating factor, (6) paracrine stimulation by macrophage products including interleukin-1, interleukin-6 and tumor necrosis factor, (7) overexpression of c-erbB-2 (HER-2/neu) in 30% of cases, and (8) mutation with consequent overexpression of p53 in 50% of advanced ovarian cancers. A poor clinical prognosis is associated with expression or overexpression of the epidermal growth factor receptor, fms, and HER-2/neu. Antibodies against the extracellular domain of the HER-2/neu gene product p185 inhibit the growth of tumor cells that overexpress HER-2/neu and are associated with marked decreases in diacylglycerol levels. The intracellular kinase domain is required for growth inhibition. Antibodies that inhibit growth stimulate phosphorylation of intracellular substrates. Ricin A chain monoclonal antibody conjugates that react with p185 also inhibit the growth of tumor cells that overexpress p185. The intracellular kinase region is not required for immunotoxin-mediated killing. Coexpression of HER-2/neu and the epidermal growth factor receptor has been observed in 65% of epithelial ovarian cancers and in a limited number of normal tissue from a fraction of donors.

CONCLUSIONS

Multiple alterations in growth factors, protooncogenes and growth factors have been detected in different epithelial ovarian cancers. Inappropriate signalling from receptor tyrosine kinases may be particularly important for ovarian oncogenesis. Drugs that affect tyrosine kinase and phosphatase activity deserve attention as potential therapeutic agents for ovarian cancer. The extracellular domains of the HER-2/neu gene product p185 and the epidermal growth factor receptor may provide useful targets for serotherapy.

Conformation of complementarity determining region L1 loop in murine IgG lambda light chain extends the repertoire of canonical forms

The refined structure of Se155-4 Fab fragment, the first murine antibody with the lambda light chain, reveals a novel conformation of the light chain complementarity determining region L1. This conformation extends the repertoire of canonical structures. The main determinant of this conformation is the packing of the Val27c side-chain into a hydrophobic pocket formed by the side-chains of Ala33, Leu66, Ala71 and Leu90. The framework L-FR3 loop, encompassing residues 66 to 72, which packs next to the L1 loop, bends significantly more toward the exterior of the molecule than in other Fab fragments. Sequence analysis suggests that the conformations of the L1 and L-FR3 loops observed in Se155-4 are adopted by a majority of murine lambda light chains.

Mesangial cell immune injury. Hemodynamic role of leukocyte- and platelet-derived eicosanoids

The role of leukocytes and platelets and of leukocyte- and platelet-derived eicosanoids in mediating acute changes in renal and glomerular hemodynamics was assessed in a model of antibody-induced mesangial cell injury in the rat. After a single intravenous injection (6 mg/kg) of the monoclonal antibody (ER4) against the mesangial cell membrane antigen Thy 1, significant decrements in glomerular filtration rate (GFR) and renal blood flow (RBF) were observed at 1 h, and were associated with increments in glomerular LC (+) leukocyte counts and in the synthesis of thromboxane (Tx)B2, leukotriene (LT)B4, and 12-hydroxyeicosatetraenoic acid (HETE). In rats with immune leukopenia, the rise in glomerular LC (+) leukocytes and in eicosanoid synthesis were abolished and the fall in GFR and RBF after administration of ER4 were completely ameliorated. Likewise, pretreatment of rats with both a thromboxane synthase and a 5-lipoxygenase inhibitor also blocked the fall in GFR and RBF and the rise in glomerular synthesis of TxB2 and LTB4 produced by ER4 without changing glomerular LC (+) leukocyte counts. Selective inhibition of thromboxane or 5-lipoxygenase alone only partially ameliorated the decrements in GFR and RBF produced by ER4. In animals with immune thrombocytopenia, the elevated glomerular synthesis of 12-HETE and fall in RBF but not GFR was ameliorated after administration of ER4. The ER4 antibody-induced fall in GFR was mainly caused by a marked decrement in the ultrafiltration coefficient, Kf, which was dependent on TxA2 and 5-lipoxygenase products, since pretreatment of animals with a thromboxane receptor antagonist or with a 5-lipoxygenase inhibitor partially ameliorated this decrement. Structural changes such as infiltration of glomerular capillaries by leukocytes and endothelial cell damage may also have accounted for the fall in Kf. These observations indicate that in antibody-mediated mesangial cell injury, infiltrating leukocytes and platelets mediate the changes in renal hemodynamics via synthesis of thromboxane and arachidonate 5-lipoxygenation products.

Angiotensin II regulates parathyroid hormone-related protein expression in cultured rat aortic smooth muscle cells through transcriptional and post-transcriptional mechanisms

Parathyroid hormone-related protein (PTHrP), a tumor product responsible for malignancy-associated hypercalcemia, is also produced in many normal tissues, including vascular smooth muscle cells (SMC). As PTHrP exhibits vasodilatory properties, we postulated that other vasoactive agents may control PTHrP gene expression in SMC. Addition of angiotensin II to serum-deprived SMC resulted in a marked induction of PTHrP mRNA by 2 h, with a peak (6-10-fold) at 4-6 h. Angiotensin II effects on PTHrP gene expression were inhibited by saralasin, an angiotensin II receptor antagonist, and blocked by actinomycin D and cycloheximide, suggesting a requirement for gene transcription and protein synthesis. Nuclear run-off assays revealed a 3-fold increase in PTHrP gene transcription 1 h after angiotensin II treatment. Angiotensin II also prolonged PTHrP mRNA half-life by 2-3-fold. Angiotensin-induced PTHrP mRNA is partially dependent on cyclooxygenase products and protein kinase C activation. Other vasoconstrictor substances, including serotonin and bradykinin, also stimulated PTHrP expression, whereas the vasodilator atrial natriuretic peptide did not. Addition of recombinant PTHrP-(1-141) significantly inhibited angiotensin II-induced SMC DNA synthesis. PTHrP expression is increased by angiotensin II through transcriptional and post-transcriptional mechanisms. In addition, PTHrP modulates the effect of angiotensin II on SMC proliferation. This suggests that PTHrP acts locally in SMC, possibly to oppose the vasoactive and/or growth-promoting effects of vasoconstrictor agents such as angiotensin II.

Inhibitory effects of tetrandrine on bovine serum albumin-induced uveitis in rabbits

Experimental uveitis was successfully induced in rabbits by bovine serum albumin (BSA). Tetrandrine (Tet), 50 mg/kg/d i.p., and dexamethasone (Dex), 5 mg/kg/d i.p., for 8 d showed marked inhibition of uveitis in rabbits. Eight d after drug administration, ocular inflammation was markedly inhibited. The maximum inhibitory rate of Tet and Dex was 48.9% and 56.0%, respectively. The protein content of the aqueous humor (PAH) was reduced significantly; phytohemagglutinin (PHA)-induced peripheral T lymphocyte transformation of 3H-thymidine (3H TdR) incorporation was suppressed markedly; and serum circulating immune complexes (CIC) also were reduced. Four d after Dex withdrawal, ocular inflammation, PHA and CIC rose again, but these parameters were not changed after Tet withdrawal. These results suggest that Tet is an effective inhibitory agent on BSA-induced uveitis in rabbits. The inhibiting action may be related to the suppression of cellular and humoral immune function and, unlike Dex, Tet did not produce withdrawal rebound.

[Analysis of 805 children with Salmonellae infection]

We analyzed 805 children with Salmonellae infection admitted during 1981-1991. 353 of them had typhoid fever. Most of the children were over 3 years old and came from rural area. One child died. Those under 3 years of age had non-typhoid Salmonellae infection, manifesting as enteritis pattern; most sepsis patterns were seen in neonates. S. typhimurium was often seen Salmonellae infection, S. agona came next, and S. derby the third. Salmonellae infection varied, including 7 serum groups and 25 serum types. S. typhimurium and S. agona were drug resistant, with severe carrier status. Infants and young children are very liable the infection, therefore, will be the main subjects of prevention.

Renal cell carcinoma and natural killer cells: studies in a novel rat model in vitro and in vivo

The transplantable rat kidney carcinoma (RKC) provides an excellent experimental model for immunological and therapeutic studies of renal cell carcinoma. In this report, we define the biological characteristics of RKC and explore the interactions between RKC and natural killer (NK) cells. RKC, a transplantable tumor of spontaneous origin, grows progressively over a 12-week period and metastasizes to the lung when implanted orthotopically in the kidneys of female Lewis rats. Rats bearing RKC survived for an average of 10.5 +/- 1.5 (SD) weeks postimplantation. Lung metastases were visible between 7.5 and 8.5 weeks postimplantation, and by 9 to 10 weeks the incidence of metastases reached approximately 67%. Injection of the NK cell-specific monoclonal antibody 3.2.3 depleted Lewis rats of their NK activity for up to 14 days. Adherent lymphokine-activated killer cells generated from the spleens of 3.2.3-injected rats were significantly less lytic than those from control rats and contained a significantly lower percentage of 3.2.3+ cells when analyzed by flow cytometry. Groups of rats were implanted with RKC and received injections of 3.2.3 biweekly to maintain depletion of NK cells or of a control antibody, NK1.1, specific for mouse NK cells. At 10 weeks postimplantation, 3.2.3-injected rats had significantly (P < or = 0.005) larger tumors (104.4 +/- 20.1 g) than NK1.1-injected rats (75.4 +/- 13.9 g). Spleen cells and peripheral blood cells from uninjected, tumor-bearing rats had a slight but nonsignificant decrease in NK activity against 51Cr-labeled YAC-1 targets over the course of RKC progression. The activity of adherent lymphokine-activated killer cells from tumor-bearing rats was lower than that from normal rats, but not significantly. Cultured RKC cells were killed by both splenic NK cells and adherent lymphokine-activated killer cells. These data demonstrate that RKC is NK sensitive and that tumor growth does not abrogate NK activity. The RKC tumor provides a model system for the analysis of immunological factors in renal cell carcinoma growth and presents opportunities for testing therapeutic interventions in a system that closely mimics the human disease.

Human ribosomal RNA intergenic spacer sequence

Images

Opponent-processing effects on the field spectral sensitivity of pattern-elicited electroretinograms

Field spectral sensitivities of the pattern-elicited electroretinogram (PERG) were obtained from two subjects using a modified version of Stiles' two-color increment threshold procedure. A 540 nm checkerboard test pattern of 38 degrees dia was alternated at 8 Hz on a uniform adapting field of the same size. Test intensity, field wavelength and field intensity were varied parametrically. The derived field spectral sensitivity does not resemble that of any individual class of cones; it roughly approximates the photopic luminosity function V lambda, but with sensitivity dips at 540 and 600 nm, which may be associated with an adaptation of the red/green (R/G) opponent site. Thus, it is proposed that the PERG reflect activities in both the luminance and the R/G opponent channels.