DNA sequence analysis of NKG2, a family of related cDNA clones encoding type II integral membrane proteins on human natural killer cells

We have previously described the isolation of a cDNA clone, designated NKG2, that was expressed in all natural killer (NK) cells tested but not in T or B cells. In the present communication, the original isolate, when used to probe a cDNA library prepared from a CD3- NK cell clone, was found to crosshybridize with a family of transcripts that fell into four distinct groups designated NKG2-A, -B, -C, and -D. Full-length cDNA sequences were determined for each group, and the DNA and inferred peptide sequences were analyzed. All four transcripts encode type II membrane proteins of 215-233 amino acids. NKG2-A and -B peptides appear to be alternative splicing products of a single gene. NKG2-C is highly homologous with group A, having 94% homology in the external (COOH-terminal) domain and 56% homology throughout the internal and transmembrane regions. NKG2-D is distantly but significantly related (21% amino acid homology) to the first three groups. Therefore, NKG2-A, -C, and -D appear to be encoded by distinct genes within a family of NK cell-specific genes. Peptide sequence homology searches demonstrate that the NKG2 peptides are members of a supergene family that includes several other type II membrane proteins. This family is characterized by the presence of a C-type animal lectin domain, and several of its members have demonstrated transmembrane signaling capability.

Renal ischemia/reperfusion remotely improves myocardial energy metabolism during myocardial ischemia via adenosine receptors in rabbits: effects of "remote preconditioning"

OBJECTIVES

This study examined the changes in myocardial energy metabolism during myocardial ischemia after "remote preconditioning" and investigated the involvement of adenosine receptors in the mechanisms of this effect.

BACKGROUND

Recent studies have indicated that a brief period of ischemia and reperfusion (ischemic preconditioning, PC) in a remote organ reduces myocardial infarct size (IS) protecting against subsequent sustained myocardial ischemia. However, the mechanisms of "remote PC" remain unclear. We assessed myocardial energy metabolism during sustained myocardial ischemia and reperfusion after renal PC (RPC), in comparison with that after myocardial PC (MPC) in open-chest rabbits. It has been established that adenosine receptors are involved in the mechanisms of MPC.

METHODS

Rabbits that had been anesthetized with halothane were divided into six groups. The control (CNT) group underwent 40-min coronary occlusion followed by 120 min reperfusion. Before the procedure, the MPC group underwent an additional protocol of 5 min coronary artery occlusion and 20 min reperfusion, and the RPC group received a 10 min episode of renal artery occlusion and 20 min reperfusion. In additional experimental groups, 8 sulfophenyl-theophylline (SPT, 10 mg/kg), an adenosine receptor inhibitor, was intravenously injected before the 40 min myocardial ischemia (SPT, MPC + SPT and RPC + SPT groups, respectively). Myocardial levels of phosphocreatine (PCr), ATP and intracellular pH (pHi) were measured by 31P-NMR spectroscopy.

RESULTS

RPC and MPC delayed the decreases in ATP levels, preserved pHi during 40-min myocardial ischemia and resulted in better recovery of ATP and PCr during 120 min reperfusion compared with the controls. SPT abolished the improvement in myocardial energy metabolism and the reduction in myocardial IS caused by MPC or RPC. Myocardial IS in the CNT (n = 8), MPC (n = 9), RPC (n = 9), SPT (n = 6), MPC + SPT (n = 8) and RPC + SPT (n = 8) groups averaged 42.8+/-3.5%, 18.2+/-1.8%*, 19.6+/-1.3%*, 44.9+/-5.0%, 35.6+/-2.7% and 34.8+/-3.6% of the area at risk (*p < 0.05 vs. CNT), respectively.

CONCLUSIONS

PC in a remote organ, similar to MPC, improved myocardial energy metabolism during ischemia and reperfusion and reduced IS in vivo by an adenosine-dependent mechanism in rabbits.

Quantitative measurements of cardiac phosphorus metabolites in coronary artery disease by 31P magnetic resonance spectroscopy

BACKGROUND

31P metabolite measurements in the human heart by magnetic resonance spectroscopy (MRS) have been reported previously. By use of a method in which metabolite content was quantified with reference to a standard located outside the chest, it has become possible to measure the content of phosphocreatine (PCr) and ATP in vivo in the human heart. In this study, PCr and ATP contents were measured by 31P MRS and compared in human myocardium with reversible ischemia or scar diagnosed by exercise thallium scintigraphy.

METHODS AND RESULTS

Forty-one subjects with stenosis of the left anterior descending coronary artery (> 50%) and 11 healthy control subjects (C) composed the present study group. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+], n = 29) who demonstrated redistribution at late image and a fixed 201Tl defect group (RD[-], n = 12). While the subjects lay supine within the magnet, 31P MR spectra were obtained from the anterior and apical regions of the left ventricle by slice-selected one-dimensional chemical shift imaging. For metabolite quantification, a standard was placed at the center of the surface coil. ANOVA revealed significant differences among the three groups with respect to the mean (+/- SD) PCr at rest (C, 12.14 +/- 4.25 > RD[+], 7.64 +/- 3.00 > RD[-], 3.94 +/- 2.21 mumol/g wet heart tissue, P < .05) as well as a significant decrease in ATP in the RD(-) group (C, 7.72 +/- 2.97; RD[+], 6.35 +/- 3.17 > RD[-], 4.35 +/- 1.52 mumol/g wet heart tissue, P < .05).

CONCLUSIONS

Compared with healthy control subjects, PCr content decreased significantly in patients with both reversible and fixed 201Tl defects, and ATP content decreased significantly in subjects with fixed thallium defects. These results suggest that the measurement of ATP content in the human heart by 31P MRS is a clinically important method for the evaluation of myocardial viability.

The eukaryotic UDP-N-acetylglucosamine pyrophosphorylases. Gene cloning, protein expression, and catalytic mechanism

A search of the yeast data base for a protein homologous to Escherichia coli UDP-N-acetylglucosamine pyrophosphorylase yielded UAP1 (UDP-N-acetylglucosamine pyrophosphorylase), the Saccharomyces cerevisiae gene for UDP-N-acetylglucosamine pyrophosphorylase. The Candida albicans and human homologs were also cloned by screening a C. albicans genomic library and a human testis cDNA library, respectively. Sequence analysis revealed that the human UAP1 cDNA was identical to previously reported AGX1. A null mutation of the S. cerevisiae UAP1 (ScUAP1) gene was lethal, and when expressed under the control of ScUAP1 promoter, both C. albicans and Homo sapiens UAP1 (CaUAP1 and HsUAP1) rescued the ScUAP1-deficient S. cerevisiae cells. All the recombinant ScUap1p, CaUap1p, and HsUap1p possessed UDP-N-acetylglucosamine pyrophosphorylase activities in vitro. The yeast Uap1p utilized N-acetylglucosamine-1-phosphate as the substrate, and together with Agm1p, it produced UDP-N-acetylglucosamine from N-acetylglucosamine-6-phosphate. These results demonstrate that the UAP1 genes indeed specify eukaryotic UDP-GlcNAc pyrophosphorylase and that phosphomutase reaction precedes uridyltransfer. Sequence comparison with other UDP-sugar pyrophosphorylases revealed that amino acid residues, Gly112, Gly114, Thr115, Arg116, Pro122, and Lys123 of ScUap1p are highly conserved in UDP-sugar pyrophosphorylases reported to date. Among these amino acids, alanine substitution for Gly112, Arg116, or Lys123 severely diminished the activity, suggesting that Gly112, Arg116, or Lys123 are possible catalytic residues of the enzyme.

Cloning of the Candida albicans homolog of Saccharomyces cerevisiae GSC1/FKS1 and its involvement in beta-1,3-glucan synthesis

Saccharomyces cerevisiae GSC1 (also called FKS1) and GSC2 (also called FKS2) have been identified as the genes for putative catalytic subunits of beta-1,3-glucan synthase. We have cloned three Candida albicans genes, GSC1, GSL1, and GSL2, that have significant sequence homologies with S. cerevisiae GSC1/FKS1, GSC2/FKS2, and the recently identified FKSA of Aspergillus nidulans at both nucleotide and amino acid levels. Like S. cerevisiae Gsc/Fks proteins, none of the predicted products of C. albicans GSC1, GSL1, or GSL2 displayed obvious signal sequences at their N-terminal ends, but each product possessed 10 to 16 potential transmembrane helices with a relatively long cytoplasmic domain in the middle of the protein. Northern blotting demonstrated that C. albicans GSC1 and GSL1 but not GSL2 mRNAs were expressed in the growing yeast-phase cells. Three copies of GSC1 were found in the diploid genome of C. albicans CAI4. Although we could not establish the null mutation of C. albicans GSC1, disruption of two of the three GSC1 alleles decreased both GSC1 mRNA and cell wall beta-glucan levels by about 50%. The purified C. albicans beta-1,3-glucan synthase was a 210-kDa protein as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and all sequences determined with peptides obtained by lysyl endopeptidase digestion of the 210-kDa protein were found in the deduced amino acid sequence of C. albicans Gsc1p. Furthermore, the monoclonal antibody raised against the purified beta-1,3-glucan synthase specifically reacted with the 210-kDa protein and could immunoprecipitate beta-1,3-glucan synthase activity. These results demonstrate that C. albicans GSC1 is the gene for a subunit of beta-1,3-glucan synthase.

Ferulic acid induces neural progenitor cell proliferation in vitro and in vivo

Ferulic acid (4-hydroxy-3-methoxycinnamic acid; FA) is a plant constituent and is contained in several medicinal plants for clinical use. In this paper, we investigated the effects of FA on the proliferation of neural stem/progenitor cells (NSC/NPCs) in vitro and in vivo. FA significantly increased the proliferation of NSC/NPCs cultured from the telencephalon of embryonic day-14 rats, and increased the number and size of secondary formed neurospheres. An in vitro differentiation assay showed that FA did not affect the percentage of either neuron-specific class III beta-tubulin (Tuj-1)-positive cells or glial fibrillary acidic protein (GFAP)-positive cells in the total cell population. Oral administration of FA increased the number of newly generated cells in the dentate gyrus (DG) of the hippocampus of corticosterone (CORT)-treated mice, indicating that FA enhances the proliferation of adult NSC/NPCs in vivo. We also found that oral administration of FA increased cAMP response element binding protein (CREB) phosphorylation and brain-derived neurotrophic factor (BDNF) mRNA level in the hippocampus of CORT-treated mice, and ameliorated the stress-induced depression-like behavior of mice. These novel pharmacological effects of FA may be useful for the treatment of mood disorders such as depression.

Cooperative roles of Bozozok/Dharma and Nodal-related proteins in the formation of the dorsal organizer in zebrafish

In vertebrates, specification of the dorso-ventral axis requires Wnt signaling, which leads to formation of the Nieuwkoop center and the Spemann organizer (dorsal organizer), through the nuclear accumulation of beta-catenin. Zebrafish bozozok/dharma (boz) and squint (sqt), which encode a homeodomain protein and a Nodal-related protein, respectively, are required for the formation of the dorsal organizer. The zygotic expression of boz and sqt in the dorsal blastoderm and dorsal yolk syncytial layer (YSL) was dependent on the maternally derived Wnt signal, and their expression at the late blastula and early gastrula stages was dependent on the zygotic expression of their own genes. The dorsal organizer genes, goosecoid (gsc) and chordin (din), were ectopically expressed in wild-type embryos injected with boz or sqt RNA. The expression of gsc strictly depended on both boz and sqt while the expression of din strongly depended on boz but only partially depended on sqt and cyclops (cyc, another nodal-related gene). Overexpression of boz in embryos defective in Nodal signaling elicited the ectopic expression of din but not gsc and resulted in dorsalization, implying that boz could induce part of the organizer, independent of the Nodal proteins. Furthermore, boz; sqt and boz;cyc double mutants displayed a severely ventralized phenotype with anterior truncation, compared with the single mutants, and boz;sqt;cyc triple mutant embryos exhibited an even more severe phenotype, lacking the anterior neuroectoderm and notochord, suggesting that Boz/Dharma and the Nodal-related proteins cooperatively regulate the formation of the dorsal organizer.

NFkappaB activation is required for the neuroprotective effects of pigment epithelium-derived factor (PEDF) on cerebellar granule neurons

Pigment epithelium-derived factor (PEDF) protects immature cerebellar granule cells (1-3 days in vitro) against induced apoptosis and mature cells (5+ days in vitro) against glutamate toxicity, but its precise mechanism is still unknown. Because the transcription factor NFkappaB blocks cell death, including neuronal apoptosis, we have investigated the ability of PEDF to exert its effects via NFkappaB activation. PEDF induced an increased phosphorylation of IkappaBalpha, decreased levels of IkappaB proteins, and translocation of p65 (RelA) to the nucleus followed by a time-dependent increase of NFkappaB-DNA binding activity in both immature and mature neurons. The protective effects of PEDF against both induced apoptosis and glutamate toxicity were blocked by the addition of either the IkappaB kinase inhibitor BAY 11-7082, which inhibits the phosphorylation of IkappaB, or N-acetyl-Leu-Leu-norleucinal, which blocks proteosome degradation of IkappaB, demonstrating that NFkappaB is required for the neuroprotective effects of PEDF. Reverse transcription-polymerase chain reaction analysis revealed that up-regulation of the anti-apoptotic genes for Bcl-2, Bcl-x, and manganese superoxide dismutase was observed in PEDF-treated immature but not mature neurons. Up-regulation of nerve growth factor, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor mRNA was long-lasting in mature neurons. These results suggest that PEDF promotes neuronal survival through activation of NFkappaB, which in turn induces expression of anti-apoptotic and/or neurotrophic factor genes.

Killer cell immunoglobulin receptors and T cell receptors bind peptide-major histocompatibility complex class I with distinct thermodynamic and kinetic properties

Human natural killer cells and a subset of T cells express a repertoire of killer cell immunoglobulin receptors (KIRs) that recognize major histocompatibility complex (MHC) class I molecules. KIRs and T cell receptors (TCRs) bind in a peptide-dependent manner to overlapping regions of peptide-MHC class I complexes. KIRs with two immunoglobulin domains (KIR2Ds) recognize distinct subsets of HLA-C alleles. Here we use surface plasmon resonance to study the binding of soluble forms of KIR2DL1 and KIR2DL3 to several peptide-HLA-Cw7 complexes. KIR2DL3 bound to the HLA-Cw7 allele presenting the peptide RYRPGTVAL with a 1:1 stoichiometry and an affinity (K(d) approximately 7 microM at 25 degrees C) within the range of values measured for other cell-cell recognition molecules, including the TCR. Although KIR2DL1 is reported not to recognize the HLA-Cw7 allele in functional assays, it bound RYRPGTVAL/HLA-Cw7, albeit with a 10-20-fold lower affinity. TCR/peptide-MHC interactions are characterized by comparatively slow kinetics and unfavorable entropic changes (Willcox, B. E., Gao, G. F., Wyer, J. R. , Ladbury, J. E., Bell, J. I., Jakobsen, B. K., and van der Merwe, P. A. (1999) Immunity 10, 357-365), suggesting that binding is accompanied by conformational adjustments. In contrast, we show that KIR2DL3 binds RYRPGTVAL/HLA-Cw7 with fast kinetics and a favorable binding entropy, consistent with rigid body association. These results indicate that KIR/peptide-MHC class I interactions have properties typical of other cell-cell recognition molecules, and they highlight the unusual nature of TCR/peptide-MHC recognition.

Role of three chitin synthase genes in the growth of Candida albicans

The CHS2 and CHS3 genes of Candida albicans were disrupted. The double disruptant was still viable. Assessment of chitin and of calcofluor white resistance shows that CHS1 is responsible for septum formation and CHS3 is responsible for overall chitin synthesis otherwise. There were only small differences in virulence to immunocompromised mice of homozygous chs2 delta amd chs3 delta null mutants.

A multigene family on human chromosome 12 encodes natural killer-cell lectins

We previously isolated a series of cDNA clones designated NKG2-A, B, C, and D from a human natural killer (NK) cell library. These transcripts encode a family of type II integral membrane proteins having an extracellular Ca(2+)-dependent lectin domain. The predicted peptides share structural similarities and amino acid sequence similarity with known receptor molecules. In this report, the genomic organization and mRNA expression of each of the genes were studied by using transcript-specific probes. Southern blot experiments reveal that the probes cross-hybridize with a maximum of five genes at high stringency. By probing a Southern blot prepared from a series of hamster/human hybrid somatic cell lines, we demonstrated that all of the hybridizing fragments occur on human chromosome 12. No gene rearrangement and little restriction fragment length polymorphism (RFLP) was observed with these probes. mRNA expression of the NKG2 genes occurred in NK cells and some T cells but not in other hematopoietic cell types or in other tissues tested. Each of the transcripts occurred in all three of the NK cell lines tested: however, the genes were differentially regulated in T cells. NKG2-D was expressed in nine of fourteen T-cell clones or lines in the panel, whereas NKG2-A/B was expressed in three and NKG2-C was expressed in only one. Expression of each of the transcripts was upregulated following T-cell growth factor (TCGF)-induced activation of a cloned NK cell. The limited distribution of these proteins and their sequence similarity with known receptor molecules suggest that they may function as receptors on human NK cells.

Long-term survival of functional hepatocytes from adult rat in the presence of phenobarbital in primary culture

In the presence of phenobarbital (PB) at 3 mM, hepatocytes isolated from adult rats by a collagenase-perfusion technique survived well on plastic dishes for at least 49 days after initiation of primary culture. PB at concentrations less than 3 mM was ineffective for the maintenance of hepatocytes, and the maintenance of them was attained only in the continuous presence of 3 mM PB. The hepatocytes surviving in the presence of 3 mM PB were morphologically indistinguishable from the hepatocytes after 1-day attachment period, except for the presence of prominent nucleoli in the former. Although both the albumin secretion and tyrosine aminotransferase (TAT) activities of the cells decreased gradually up to day 7 with time in culture, both were thereafter maintained at relatively high levels at least up to day 35 of primary culture. The addition of 10 microM dexamethasone caused a 3-5-fold induction in TAT activity, and the cells were capable of responding to the hormone in this manner at least up to day 28 of primary culture. Furthermore, the cells also had glucose-6-phosphatase activity, even though the level of this enzyme activity was relatively low as compared with that of TAT activity. Survival of hepatocytes in the presence of 3 mM PB was further enhanced by simultaneous addition of dexamethasone (10 microM) and insulin (10 micrograms/ml). The sensitivity of hepatocytes to 3'-methyl-4-dimethylaminoazobenzene (0.24 mM) was remarkably reduced by treatment with PB at 3 mM. PB treatment decreased efficiently the falling rate of total cytochrome P-450 content, but did not induce P-450PB, which is the specific form of cytochrome P-450 induced by PB, in primary cultured hepatocytes. On the other hand, 3-methylcholanthrene (MC, 10 microM) caused an increase of both contents of total cytochrome P-450 and P-450MC, which is the specific form of cytochrome P-450 induced by MC, in primary cultured hepatocytes. However, MC was ineffective for the maintenance of hepatocytes in primary culture. The possible biological actions of PB on primary cultured hepatocytes are discussed on the basis of the experimental data obtained.

Activation of human Valpha24NKT cells by alpha-glycosylceramide in a CD1d-restricted and Valpha24TCR-mediated manner

Vact14NK(natural killer) T cells play an important role in controlling tumors or in preventing autoimmunity in the murine system. Valpha24NKT cells, the human counterpart of Valpha14NKT cells, may contribute to controlling the progression of autoimmune diseases in humans. These findings show the possibility that ligand(s) for these NKT cells can control the above-mentioned pathological conditions. Specific glycolipids such as alpha-galactosylceramide (alpha-GalCer) and alpha-glucosylceramide (alpha-GlcCer) have been identified as ligand(s) recognized by murine Valpha14NKT cells in a CD1d-restricted manner, but it remains unclear whether these glycolipids are ligand(s) for Valpha24NKT cells in humans. To determine whether alpha-glycosylceramide is presented by CD1d molecules in humans, we initially established a Valpha24NKT cell line specific for alpha-glycosylceramide using dendritic cell (DC) like cells from normal peripheral blood mononuclear cells (PBMC) in an autologous mixed leukocyte reaction (auto-MLR) system, and characterized the Valpha24NKT cell line. The Valpha24NKT cells were CD3+ CD4-CD8-Valpha24+Vbeta11+NKRP1A+ and specifically proliferated in response to alpha-glycosylceramide in CD1d-restricted and Valpha24TCR-mediated manner. The phenotypic and functional similarities between murine Valpha14NKT cells and human Valpha24NKT cells suggest that Valpha24NKT cells may play an important role in controlling tumors or in preventing autoimmunity as observed with Valpha14NKT cells.

Regulation of dharma/bozozok by the Wnt pathway

The zebrafish homeobox gene dharma/bozozok (boz) is required for the formation and/or function of the Nieuwkoop center and the subsequent induction of the Spemann organizer. dharma is expressed soon after the midblastula transition in the dorsal blastomeres and the dorsal yolk syncytial layer (YSL). We found that the expression of dharma was upregulated or ectopically induced by misexpression of a Wnt protein and cytoplasmic components of the Wnt signaling pathway and downregulated by the expression of dominant-negative Tcf3. A 1.4-kbp fragment of the dharma promoter region contains consensus sequences for Tcf/Lef binding sites. This promoter region recapitulated the Wnt-dependent and dorsal dharma expression pattern when it was fused to luciferase or GFP. Deletion and point mutant analyses revealed that the Tcf/Lef binding sites were required to drive this expression pattern. These data established that dharma/boz functions between the dorsal determinants-mediated Wnt signals and the formation of the Nieuwkoop center.

Detection of myocardial ischemia by 31P magnetic resonance spectroscopy during handgrip exercise

BACKGROUND

The metabolic changes of myocardial ischemia in patients with coronary artery disease assessed by 31P magnetic resonance spectroscopy (MRS) have been reported previously. A significant decrease in the ratio of phosphocreatine (PCr) to ATP during handgrip exercise in a group of patients with severe coronary artery disease has been demonstrated. However, there are no reports at present that directly compare cardiac 31P MRS data with exercise 201Tl myocardial scintigraphy, now established as one of the most important clinical methods to assess myocardial ischemia. The purpose of this study was to investigate whether 31P MRS with handgrip exercise testing is able to detect myocardial ischemia, demonstrated by exercise 201Tl scintigraphy.

METHODS AND RESULTS

Twenty-seven patients with severe stenosis of the left anterior descending coronary artery (> or = 75%) and 11 normal control subjects composed the present study. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+]) who demonstrated redistribution at the late image and a fixed 201Tl defect group (RD[-]). While lying supine within the magnet, subjects performed handgrip exercise at 30% of maximal force once in every two cardiac cycles. 31P MR spectra were collected before and during handgrip exercise. Data were corrected for the saturation factor. ANOVA revealed significant differences among the three groups with respect to the mean +/- SD PCr/ATP ratio at rest (control, 1.85 +/- 0.28 > RD(+), 1.60 +/- 0.19 > RD(-), 1.24 +/- 0.30; P < .05). The PCr/ATP ratio decreased significantly from 1.60 +/- 0.19 at rest to 0.96 +/- 0.28 during exercise (P < .001) in the RD(+) group (n = 15). However, in the RD(-) group (n = 12), the ratio did not change significantly during handgrip exercise (1.24 +/- 0.30 at rest versus 1.19 +/- 0.28 during exercise). Similarly, the ratio did not change in the control group (n = 11) (1.85 +/- 0.28 at rest versus 1.90 +/- 0.23 during exercise).

CONCLUSIONS

Contrary to normal subjects or patients with fixed thallium defects, the PCr/ATP ratio was significantly altered by exercise in patients with reversible thallium defects. These results suggest that 31P MRS with handgrip exercise testing is a sensitive method for detecting myocardial ischemia.

Expression of the zinc finger gene fez-like in zebrafish forebrain

Anterior-posterior (A-P) patterning in the neuroectoderm is established during gastrulation in zebrafish and amphibians. We isolated a novel zinc-finger gene fez-like (fezl) from zebrafish, which displays sequence similarities to Xenopus Fez. The fezl transcripts were detected in the anterior edge of neuroectoderm, the prospective dorsal forebrain, from the late gastrula (80% epiboly stage) to the mid-segmentation period. fezl was also expressed in the ventral forebrain overlying the prechordal plate at these stages. The expression of fezl was enhanced in embryos expressing the Wnt inhibitor Dkk1 and reduced in embryos expressing Wnt8b. The expression in the ventral forebrain was eliminated in the one-eyed pinhead mutant and the antivin RNA-injected embryos, which lack the prechordal plate. Radiation hybrid mapping revealed that the fezl gene is localized to linkage group 11.

Tolerance of NK and LAK activity for HLA class I-deficient targets in a TAP1-deficient patient (bare lymphocyte syndrome type I)

NK cells recognize target cells that lack HLA class I molecules and lyse them, according to the 'missing self' hypothesis. It was previously reported that a TAP2-deficient patient with an HLA class I-deficiency, had a normal number of NK cells but that the lymphocytes of this patient had lost their NK activity against K562 cells. In this study, we investigated the HLA class I-recognizing NK receptor expressions and the NK and LAK activities of the lymphocytes of a TAP1-deficient patient. The patient had a normal number of NK cells. Although the lymphocytes showed LAK activity against class I expressing targets following IL-2, IL-12 and IL-15 stimulation for 3 days, neither NK nor LAK activity against targets lacking class I molecules was induced. The NK cells of the patient expressed class I-recognizing NK receptors, although the percentages of such cells were low. However, no differences were observed in the expression levels of inhibitory and activating NK receptors between lymphocytes of the patient and those of healthy controls, suggesting that the modulation of the NK receptor expression is not primarily responsible for this tolerance. These results also suggest that the lymphocytes of the patient are defective in the recognition of class I-deficient target cells in order to promote the induction of self tolerance.

Onjisaponins, from the root of Polygala tenuifolia Willdenow, as effective adjuvants for nasal influenza and diphtheria-pertussis-tetanus vaccines

Active substances from hot water extracts from 267 different Chinese and Japanese medicinal herbs were screened for mucosal adjuvant activity with influenza HA vaccine in mice. The extract from the root of Polygala tenuifolia was found to contain potent mucosal adjuvant activity. The active substances were purified and identified as onjisaponins A, E, F, and G. When each onjisaponin (10 microg) was intranasally (i.n.) inoculated with influenza vaccine (10 microg) in mice, serum hemagglutination-inhibiting (HI) antibody titers increased 3-14 times over control mice administered vaccine alone after 4 weeks. When each onjisaponin (10 microg) was i.n. inoculated with the vaccine (10 microg) followed by i.n. vaccination of the vaccine alone after 3 weeks, serum HI antibody titers increased 27-50 fold over those mice given i.n. vaccinations without onjisaponins. These same conditions also significantly increased nasal anti-influenza virus IgA antibody titers. Two inoculations with onjisaponin F (1 microg) and influenza HA vaccine (1 microg) at 3 weeks intervals, significantly increased serum HI antibody and nasal anti-influenza virus IgA and IgG antibody titers after only 1 week over mice given HA vaccine alone after the secondary vaccination. Intranasal vaccination with onjisaponin F inhibited proliferation of mouse adapted influenza virus A/PR/8/34 in bronchoalveolar lavages of infected mice. Separate intranasal vaccinations with onjisaponins A, E, F, and G (10 microg) each and diphtheria-pertussis-tetanus (DPT) vaccine (10 microg) of mice followed by i.n. vaccination with DPT vaccine alone after 4 weeks showed significant increases in serum IgG and nasal IgA antibody titers after 2 weeks following secondary vaccination over mice vaccinated with DPT vaccine alone. All onjisaponins showed little hemolytic activity at concentrations up to 100 microg/ml. The results of this study suggest that onjisaponins may provide safe and potent adjuvants for intranasal inoculation of influenza HA and DPT vaccines.

Osteopontin involvement in integrin-mediated cell signaling and regulation of expression of alkaline phosphatase during early differentiation of UMR cells

To clarify the function of osteopontin in osteoblast differentiation, we have examined the signal transduction pathway in an osteoblastic cell line (UMR106-6) bound to osteopontin, fibronectin, vitronectin and collagen type I surfaces. This was done by investigating the production and autophosphorylation of focal adhesion kinase (FAK) and the expression of alkaline phosphatase (ALP) at the transcription level. Results suggest that osteopontin was not only responsible for the autophosphorylation of FAK but regulated the expression of ALP, which was strongly correlated with FAK activity. These results suggest that osteopontin might act as a trigger in the early differentiation of osteoblasts.

Medial vestibular nucleus in the guinea-pig: histaminergic receptors. II. An in vivo study

In a companion paper (Serafin et al. 1992) we have demonstrated in vitro that histamine depolarizes three previously described medial vestibular nucleus neuron (MVNn) types (Serafin et al. 1991a, b). It has also been shown that this effect was exclusively mediated through postsynaptic H2 receptors. All the same, the eventual contribution of presynaptic H3 receptors to the physiological response of the MVNn to histamine remained an open question since, during the slicing procedure, any histaminergic axons projecting to the vestibular nuclei would have been interrupted. This rendered our study of H3-mediated effects of histamine difficult. Hence, in the present in vivo study our aim was three-fold: (1) to investigate the presence of H3 receptors at the vestibular nuclei level; (2) to evaluate the functional importance of MVNn H2 receptors; and (3) to explore whether H3 ligands, when injected intraperitoneally (i.p.), could modulate dynamic vestibular functions. In order to address the first two questions, we investigated postural changes induced by perfusion of the guinea-pig's vestibular nuclear complex with specific ligands of the H2 and H3 receptors. Our data extend the conclusions of our in vitro study and suggest that lateral vestibular nuclei neurons and the MVNn are endowed with both H2 and H3 receptors. Our results indicate furthermore that histamine can modulate, quite effectively, static vestibular reflexes. Finally, the present study demonstrates that i.p. injection of thioperamide, an H3 antagonist, induces a significant decrease in the horizontal vestibular-ocular reflex gain and, by contrast to most of the clinically used antihistaminics, has no detrimental effect on the alertness level. Our results may thus lead to clinical testing and use of H3 antagonists as antivertigo or anti motion-sickness drugs.

Low dose dobutamine stress echocardiography predicts the improvement of left ventricular systolic function in dilated cardiomyopathy

OBJECTIVE

To determine whether dobutamine stress echocardiography can predict the improvement of left ventricular systolic function in patients with dilated cardiomyopathy (DCM).

METHODS

Myocardial contractile reserve, as assessed by dobutamine stress echocardiography, was determined in 18 patients with DCM (mean (SD) age 53 (13) years, left ventricular ejection fraction (LVEF) 28 (10)%) and compared with changes in LVEF during a follow up period of 15 (8) months. The LVEF and regional left ventricular wall motion score (0, normal to 4, dyskinesis) of 12 segments in short axis and four chamber views were analysed before and after dobutamine infusion (5-20 microg/kg/min).

RESULTS

During a follow up period of 15 (8) months, a significant improvement in LVEF (> 20%) was found in seven patients but not in the remaining 11. Baseline haemodynamic findings were similar in both groups. Patients with an improvement in follow up LVEF showed a greater change in wall motion score from baseline during dobutamine infusion than patients with no improvement (at rest, 1.7 (0.4) v 1.9 (0.2), NS; dobutamine 10 microg/kg/min, 0.6 (0.4) v 1.2 (0.4), p < 0.05). The percentage change in LVEF during dobutamine infusion was also significantly greater in patients who showed improvement than in those who did not. The change in LVEF during the follow up period (follow up LVEF/baseline LVEF) correlated well with the change in LVEF during dobutamine stress (LVEF at rest/LVEF at dobutamine 10 microg/kg/min; r = 0.74, p < 0.001).

CONCLUSIONS

Changes in left ventricular systolic performance during low dose dobutamine stress echocardiography are a useful marker to predict the outcome of left ventricular systolic function in patients with DCM.