[A rare etiology for HBs-Ag negative acute hepatitis B--coinfection by hepatitis B and delta]

An unusual case of a 25-year-old male Italian is reported. The patient endured an acute hepatitis without detectable HBs-antigen by coinfection with hepatitis-B and Delta. Coincidently, a cured hepatitis-C was present. Firstly hepatitis-B-virus DNA could be demonstrated in a small quantity by serodiagnosis (6 pg/ml, hybridization technique). Subsequently, the identification of B-virus DNA was only possible in liver tissue (PCR-technique), but no longer by serodiagnosis. The probable enduring inhibition of hepatitis-B-virus replication by Delta virus resulted in a self limitation of the disease within 2 months (HDV-RNA negative, HBs-Ag and HBe-Ag negative; Anti-HBs negative, Anti-HBe and Anti-HBc positive). In spite of negativation of replication markers for hepatitis-B a subsequent reactivation of the infection was possible by viral material which persisted in liver tissue.

Expression and complex formation of S100-like proteins MRP8 and MRP14 by macrophages during renal allograft rejection

MRP8 and MRP14, two S100-like calcium-binding proteins, are expressed during differentiation of monocytes/macrophages. Both assemble to different noncovalently associated complexes that are supposed to represent the biologically active states. The present study was intended to investigate the molecular basis of macrophage heterogeneity with respect to expression and complex formation of MRP8 and MRP14 during acute and chronic rejection of renal allografts. First, specificity of antisera and mAbs to be directed against MRP8, MRP14, or MRP8/MRP14 heterodimers was determined by immunocytochemical and Western blot analyses of L132 fibroblasts (co-)transfected with MRP8 and/or MRP14 cDNA. Then, immunohistochemical analysis of biopsy specimens obtained from kidney allografts after acute rejection was performed, revealing a parallel expression of MRP8 and MRP14 with coincident MRP8/MRP14 heterodimer formation in infiltrating monocytes. In contrast, chronic allograft rejection was characterized by a subpopulation of monocytes defined by the absence of MRP8/MRP14 complex formation despite expression of MRP8 and MRP14 monomers. Double-labeling experiments showed that this was due in part to differential expression of MRP8 and MRP14 in infiltrate macrophages of chronic rejection. The data presented demonstrate for the first time differences in MRP8/MRP14 complex assembly by infiltrating monocytes in situ. These seem to be of pathophysiological relevance since complex formation defines subpopulations of monocytes associated with distinct pathways of immunological reactions. Differences in the mode of calcium-dependent signaling may, therefore, be of importance for understanding the molecular basis of macrophage heterogeneity during acute and chronic allograft rejection.

Cytochemical staining for beta 1,6 branching of asparagine-linked oligosaccharides in variants of metastatic human colon carcinoma cells

A positive correlation between tumor progression in human colon and increased beta 1,6 branching in oligosaccharides has recently been demonstrated. The present study was undertaken to elucidate whether such a correlation can be extended to variants of metastasizing human colon carcinoma HCT116 cells. The Phaseolus vulgaris leukoagglutinating lectin, which binds to beta 1,6 branched oligosaccharides, was employed. In blots, a band of approximately 140 kd was detectable in both the HCT116a and HCT116b sublines. However, in the more aggressive subline HCT116a, the intensity of this band was increased by 100%, and additional reactive bands of approximately 100 kd and approximately 170 kd were observed. Analysis by electron microscopy revealed lectin labeling in the Golgi apparatus, lysosomal elements, mucus droplets, cytoplasmic vesicles, and at the plasma membrane. Quantification of the lectin plasma membrane labeling revealed a significantly higher labeling intensity in HCT116a cells than in HCT116b cells. The difference in lectin plasma membrane labeling intensity could also be observed in paraffin sections. Thus, variants of metastatic HCT116 colon carcinoma cells differ quantitatively and qualitatively in glycoproteins carrying beta 1,6 branches.

Incretin hormones regulate glucose-dependent insulin secretion in RIN 1046-38 cells: mechanisms of action

Glucagon-like peptide-1-(7-36) amide (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are known incretin hormones, released from enteroendocrine cells in response to food, that enhance insulin secretion, but only in the presence of elevated blood glucose. We used a rat insulinoma cell line, RIN 1046-38, to study the mechanisms underlying the interaction of incretins and glucose. We measured insulin secretion using RIA and the reverse hemolytic plaque assay. GLP-1 stimulates insulin secretion, with a half-maximal concentration of 34 pM. GLP-1 is approximately 2 orders of magnitude more potent than GIP. GLP-1 and GIP have additive effects at submaximal concentrations, but probably not at maximal concentrations, suggesting a common signal transduction pathway. The glucose requirement for GLP-1 action can be replaced by cell membrane depolarization (20 mM KCl in the extracellular medium), suggesting that a rise of intracellular Ca2+ may be an early step required for GLP-1 action. GLP-1 stimulates insulin secretion by significantly increasing the maximum rate of insulin secretion from 10.3 +/- 2.25 to 25.2 +/- 2.94 ng insulin/mg protein.h. GLP-1 acts by recruiting 1.5-fold more cells to secrete insulin as well as enhancing insulin secretion by individual cells. Combinations of stimuli, such as glucose, cell membrane depolarization, and GLP-1, can recruit 90% of RIN 1046-38 cells to secrete insulin.

Polysialic acid of the neural cell adhesion molecule (N-CAM) is widely expressed during organogenesis in mesodermal and endodermal derivatives

We have studied the expression of homopolymers of alpha 2,8-linked sialic acid (polySia) and the neural cell adhesion molecule (N-CAM) during the embryonic and fetal development of rat, chicken and man using immunocytochemistry and immunoblotting. During development, polySia and N-CAM were widely expressed in mesodermally and neuro-ectodermally derived elements. In specific developmental processes, cells of endodermal and ectodermal (non-neural) origin were also immunoreactive for these molecules. Loss of polySia and N-CAM immunoreactivity often accompanied differentiation of mesodermally derived cells. In cartilage formation for instance, cells in precartilaginous mesenchymal condensations stained for N-CAM and polySia until the first appearance of specific chondrocyte function, independent of the stage of development. Transient de novo expression of polySia, in newly induced ectodermal cells, paralleled the reciprocal inductive interactions of mesodermally derived cells with cells of ectodermal origin during hair follicle formation. All ectodermally derived hair follicle cells, except the putative stem cells, later ceased expression of these molecules. Ectodermal expression of polySia and N-CAM was otherwise rare. The endodermally derived epithelium of the digestive and respiratory tracts were polySia and N-CAM immunoreactive early in organogenesis (embryonic day 12 in mouse). Cells of this derivation later all became unreactive, although decrease in immunoreactivity during development was faster in derivatives of more cranial portions of the endoderm. In general, during organogenesis, epithelial elements showed polySia and N-CAM expression before and during epithelium formation, thereafter losing immunoreactivity, irrespective of the developmental origin of the epithelial cells. PolySia and N-CAM staining in the chicken respiratory tract epithelium was more wide-spread and lasted significantly longer than in either man or rat. Cells that expressed N-CAM, but not polySia, were found during the development of both skin and pancreas, indicating independent control of polySia expression. Outside the nervous system no cells that expressed polySia but not N-CAM were observed.

Expression of the calcium-binding proteins MRP8 and MRP14 in monocytes is regulated by a calcium-induced suppressor mechanism

MRP8 and MRP14 are two calcium-binding proteins of the S-100 family the expression of which is restricted to distinct stages of monocytic differentiation. Heteromeric MRP8/MRP14 complexes have been shown to represent their biologically active forms. However, it is not as yet clear whether biochemical modification of complexes, or regulation on the transcriptional level, are responsible for the control of MRP8/MRP14 expression. Employing Western-blot analysis and metabolic labelling we have demonstrated that patterns and metabolism of MRP8/MRP14 complexes do not change during up- or down-regulation of MRP8/MRP14. By Northern-blot analysis it was shown that MRP8/MRP14 are regulated at the transcriptional level rather than by biochemical modification of the complexes. Elevation of intracellular calcium levels by A23187, as well as by thapsigargin, was found to lead to specific down-regulation of MRP8/MRP14 mRNA which is in contrast with data reported for inflammatory factors such as interleukin-1 or tumour necrosis factor alpha. Concomitant application of actinomycin D and calcium ionophore indicated that this suppressive effect is mediated by decreased synthesis rather than increased degradation of MRP8/MRP14 mRNA. Finally, we demonstrated that calcium-mediated down-regulation of MRP8-MRP14 can be antagonized by cycloheximide, suggesting that a calcium-induced repressor protein is responsible for suppression of MRP8-MRP14 at the transcriptional level. Our data indicate that the function of MRP8-MRP14 is restricted to events associated with early stages of myelomonocytic activation.

Apomorphine induced cognitive changes in Parkinson's disease

Auditory event related potentials (ERPs) and visual evoked potentials (VEPs) were recorded from eight patients with Parkinson's disease, before and after a single dose of apomorphine. To assess the treatment effects, the patients' motor state, Benton visual retention test (BVRT), and digit span tests were also examined. After apomorphine, although motor performance improved, the ERP latencies were delayed and the N2-P3 ERP amplitude was significantly diminished by comparison with pretreatment values. These data suggest that apomorphine induces, besides its motor effects in patients with Parkinson's disease, a slowing down of cognitive processing. Preferential stimulation of dopamine autoreceptors in mesocortical and mesolimbic systems may represent a neural mechanism for these effects. Also, the posttreatment BVRT rotation errors significantly increased, suggesting an apomorphine induced impairment of visuospatial perception.

Substance P and calcitonin gene-related peptide modulate leukocyte infiltration to mouse skin during allergic contact dermatitis

The effects of the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) on leukocyte infiltration during allergic contact dermatitis (ACD) in mice were studied. Concomitant topical application of SP or CGRP with the allergen oxazolone resulted in enhanced leukocyte recruitment at the sites of challenge. Immunohistochemical studies revealed that the numbers of T-helper (L3T4+) and cytotoxic (Lyt-2) lymphocytes and infiltrating macrophages (BM8+) were increased. In addition, ICAM-1 and MHC class II molecule expression by these cells was enhanced after neuropeptide application. Analysis by confocal laser scanning microscopy revealed an increase in the immunoreactivity for SP and CGRP in nerve fibres during the course of ACD. Flow cytometry studies showed that SP and CGRP did not upregulate expression of the adhesion molecules ICAM-1 and VCAM-1 by murine endothelial cell lines in vitro. This suggests that increased infiltration of leukocytes during ACD is not a consequence of direct neuropeptide-promoted upregulation of endothelial adhesion molecules in vivo. In conclusion, our observations provide evidence for a modulatory role of neuropeptides in the pathogenesis of ACD.

Detection of immunoglobulin heavy-chain gene rearrangement at the single-cell level in malignant lymphomas: no rearrangement is found in Hodgkin and Reed-Sternberg cells

Hodgkin and Reed-Sternberg (HRS) cells, the neoplastic cells of Hodgkin's disease (HD), represent only a minority of the cellular infiltrate in affected tissue. Therefore, rearrangements of the immunoglobulin heavy-chain (IgH) gene detected in DNA extracted from an entire Hodgkin's lymph node cannot be attributed to the HRS cells and cannot be used as an argument for the B-cell origin of HRS cells. We developed a new method for the amplification of rearranged DNA of the IgH gene from single cells. Using 6 "forward primers" which were constructed corresponding to consensus sequences of the 6 known families of the IgH variable (V) region (framework region I) and a mix of 2 "reverse primers" corresponding to consensus sequences of the different joining (J) segments, rearrangements of all 6 V-families were detected in human peripheral blood lymphocytes. Rearranged IgH DNA could be amplified from single cells of B-cell lymphoma-cell lines and from 13 patients with B-cell non-Hodgkin's lymphomas. However, analysis of HRS cells isolated from lymph nodes of 13 patients with Hodgkin's disease did not show any rearrangement of the IgH gene locus. These findings, obtained by polymerase chain reaction (PCR) on isolated single HRS cells, contrast with previous studies that used Southern-blot analysis of entire tissues affected by Hodgkin's disease. We conclude that the neoplastic HRS cells in Hodgkin's disease--with the possible exception of the nodular paragranuloma subtype--are probably not derived from B cells.

Monoclonal antibody specific for alpha 2-->8-linked oligo deaminated neuraminic acid (KDN) sequences in glycoproteins. Preparation and characterization of a monoclonal antibody and its application in immunohistochemistry

Two particular types of sialoglycoproteins have been detected in fish: polysialoglycoproteins containing alpha 2-->8-linked polysialic acid (-->8Neu5Gc alpha 2-->)n present in unfertilized Salmonidae fish eggs, and glycoproteins bearing oligo/polymers of deaminated neuraminic acids (KDN) found in the vitelline envelope of the eggs and ovarian fluid. We report the preparation and characterization of a monoclonal antibody specifically recognizing oligo/polymers of KDN sequences in glycoproteins and its application in immunohistochemistry. Fusion of spleen cells from a BALB/c mouse immunized with a KDN-rich glycoprotein (KDN-gp) containing (-->8KDN alpha 2-->)n-->6(KDN alpha 2-->3Gal beta 1-->3G alpha lNA-c alpha 1-->3) GalNAc alpha 1-->residues, with mouse myeloma cells yielded a hybrid cell line producing a monoclonal antibody that bound to KDN-gp, but not to KDN-gp depleted of KDN residues. The specificity of the monoclonal antibody, designated mAb.kdn8kdn, was determined by an enzyme-linked immunosorbent assay using KDN-gp samples that varied in KDN content. These antigens were prepared by the selective removal of KDN residues from the native KDN-gp. The mAb.kdn8kdn reacted most strongly with the intact KDN-gp and less strongly with KDN-gp samples containing decreased numbers of KDN residues.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of gene dosage by a quantitative adaptation of the polymerase chain reaction (gd-PCR): rapid detection of deletions and duplications of gene sequences

Screening methods based on the polymerase chain reaction (PCR), such as denaturing gradient gel electrophoresis, single-stranded conformational polymorphism, and heteroduplex analysis, are powerful tools for the detection of point mutations as well as small deletions and insertions, but are unable to detect heterozygous deletions or duplications of exons, genes, or chromosomes. We now report a PCR-based approach, designated gene dosage-PCR (gd-PCR), that allows rapid screening for heterozygous deletions and duplications of genes or exons. Gene dosage-PCR is a quantitative method in which two in vitro synthesized DNA internal standards are coamplified with the genomic DNA sample, one corresponding to the gene of interest (test sequence) and the other to a reference (disomic) gene (reference sequence). Both internal standards are designed to be amplified with the same primer pairs and with efficiencies similar to those of their genomic DNA counterparts, yielding PCR products slightly smaller than those derived from genomic DNA. Amplification of approximately equimolar amounts of the two internal standards and genomic DNA, in the presence of [32P]dCTP, results in four radiolabeled PCR products; after electrophoresis and quantification of the products, gene dosage is easily calculated. For validation, genomic DNA from 56 subjects, 28 with cytogenetically documented Down syndrome (trisomy 21) and 28 controls that were disomic for chromosome 21, was assayed. Using the beta-amyloid precursor protein gene (APP: chromosome 21q21) as the test sequence, control subjects had an adjusted mean gene dose of 2.00 +/- 0.29, while subjects with Down syndrome had a mean gene dose of 3.05 +/- 0.27.(ABSTRACT TRUNCATED AT 250 WORDS)

Attenuation of fever and release of cytokines after repeated injections of lipopolysaccharide in guinea-pigs

1. The effects of repeated injections of bacterial lipopolysaccharide (LPS) at 3 day intervals on abdominal temperature and systemic release of tumour necrosis factor alpha (TNF)-like and interleukin-6 (IL-6)-like activity were measured in guinea-pigs. 2. After the third injection of LPS the fever response was significantly attenuated. 3. TNF-like activity (peak 1 h after LPS injection) and IL-6-like activity (peak 3 h after LPS injection) in plasma changed correspondingly, both being significantly reduced after the third and subsequent injections of LPS. 4. The increase of IL-6-like activity in plasma after LPS injection correlated to the febrile change in body temperature. This correlation remained manifest throughout the whole time course of the development of endotoxin tolerance. 5. The reduced production of TNF-like activity after repeated injections of LPS correlated to the attenuation of the fever index, the integration of the thermal response after LPS application. 6. The results support the hypothesis that one component of the development of endotoxin tolerance is reduced production and release of cytokines in response to repeated injections of the same amount of LPS.

Dynamic regulation of intact and C-terminal truncated insulin receptor phosphorylation in permeabilized cells

Using digitonin-permeabilized Chinese hamster ovary (CHO) cells that were transfected with intact human insulin receptors (CHO/HIRc cells), we examined insulin receptor phosphorylation and dephosphorylation using pulse-chase techniques. Insulin activated receptor autophosphorylation on tyrosyl residues to a level severalfold over basal, reaching maximal levels after 2, 5, and 10 min of stimulation at 34, 18, and 6 degrees C, respectively. Phosphopeptide analysis revealed that the triply phosphorylated form of the 1146-kinase domain of the insulin receptor was the major species, which is characteristic of the fully active tyrosine kinase function. The dephosphorylation reaction was time- and temperature-dependent with t1/2 values of 0.67 and 2 min at 18 and 6 degrees C, respectively. Vanadate completely inhibited dephosphorylation. Under similar permeabilization conditions when compared with CHO/HIRc cells, CHO/delta CT cells (CHO cells overexpressing a mutated form of the receptor with a 43 amino acid deletion at the C-terminus) stimulated with insulin exhibited larger increases in receptor autophosphorylation levels and in tyrosine kinase activity toward a synthetic peptide substrate; the rate of CHO/delta CT receptor dephosphorylation was not reduced. There was near-complete absence of insulin receptor substrate 1 (IRS-1) in the cell ghosts after permeabilization. We therefore examined the pattern of tyrosine phosphorylation and dephosphorylation of residual cellular proteins in permeabilized CHO/HIRc cells by Western blot analysis. In addition to the 95-kDa receptor beta-subunit, we detected the phosphorylation of two glycoproteins which included the commonly found 120-kDa protein and a novel 195-kDa protein whose dephosphorylation rate is slower than that of receptor beta-subunit.(ABSTRACT TRUNCATED AT 250 WORDS)

Polysialic acid of the neural cell adhesion molecule in the human thyroid: a marker for medullary thyroid carcinoma and primary C-cell hyperplasia. An immunohistochemical study on 79 thyroid lesions

We recently reported that the gold-labeled monoclonal antibody MAb 735, reactive with a long-chain form of alpha-2,8-linked polysialic acid (polySia) found on the neural cell adhesion molecule (NCAM), is useful to immunohistochemically distinguish small-cell lung carcinomas from neuroendocrine carcinomas with higher grade of differentiation (carcinoids) and other types of lung carcinomas (Am J Pathol 1991;139:297). In this study, we tested the occurrence of polySia in various types of malignant thyroid tumors and C-cell hyperplasia to determine whether polySia is a useful adjunct for the differential diagnosis of medullary thyroid carcinoma (MTC) and other thyroid neoplasms and to distinguish primary from secondary (reactive) C-cell hyperplasia (CCH). We examined formaldehyde-fixed and paraffin-embedded sections of 79 thyroid lesions, consisting of 33 MTC (14 familial and 19 sporadic tumors), 13 follicular, 11 papillary, 16 anaplastic carcinomas, and four glands with primary and two with secondary CCH. We applied a direct and an indirect immunogold-silver technique for polySia, CT, and CEA detection, respectively. All 33 MTC showed a strong cell-surface-associated immunoreactivity for polySia, which was sensitive to endoneuraminidase digestion. The polySia immunoreactivity of nerves served as an internal control in all specimens. Immunoreactivity for CT and CEA was present in all MTC with the exception of one recurrent tumor with features of an anaplastic MTC type. All other thyroid neoplasms were nonreactive for polySia, CT, and CEA. Primary CCH associated with MTC showed a strong polySia immunostaining, which was less intense in primary CCH not combined with MTC. In normal-appearing C cells and in secondary CCH, staining for polySia was absent in the majority of cases. We conclude that polySia of NCAM is a valuable marker to distinguish medullary carcinomas from other types of thyroid carcinomas. Furthermore, it allows for the discrimination of primary from secondary C-cell hyperplasia and may be helpful to better define the normal range of C cells in unaffected members of a family with a history of multiple endocrine neoplasia (MEN)-II.

Xenopus laevis oocytes, eggs and tadpoles contain immunoactive insulin

Insulin is a multifunctional polypeptide hormone that regulates metabolic processes and promotes mitogenesis and differentiation in vitro in the cells and tissues of several species. Its role in vivo during embryogenesis is still poorly understood. We have previously found insulin mRNA in mature Xenopus laevis oocytes and in embryos during neurulation (before organogenesis of the pancreas takes place). We have now measured insulin immunoactivity in mature oocytes, unfertilized eggs and day-2 tadpoles. Using reversed phase high performance liquid chromatography, we found low levels of insulin in extracts of oocytes (stage VI). Both Xenopus insulin I and II were detected in unfertilized eggs. The day-2 tadpoles (stages 31-33) also contained immunoactive insulin, and in swimming tadpoles (stage 46) a few clusters of cells containing insulin immunoactivity could be identified by indirect immunofluorescence. Immunoblot analysis was relatively insensitive, detecting insulin only in the adult Xenopus pancreas. In summary, insulin (from maternal origin and embryonic expression) appears to be present early enough in Xenopus laevis to influence developmental processes such as neurulation.

Two mutations in a conserved structural motif in the insulin receptor inhibit normal folding and intracellular transport of the receptor

Insulin initiates its biological response by binding to the extracellular domain of the insulin receptor. The N-terminal half of the alpha-subunit contains several repeats of a loosely conserved motif consisting of a central glycine plus several hydrophobic amino acid residues upstream from the glycine, Hy phi-Xaa-Xaa-Hy phi-Xaa-Hy phi-Hy phi-Xaa-Gly (where Hy phi represents a hydrophobic amino acid residue). This structural motif has been proposed to be important in determining the three-dimensional structure of the insulin binding domain. We have identified two naturally occurring mutant alleles of the insulin receptor gene in an insulin-resistant patient, substitution of Ala for Val28 and Arg for Gly366. The mutations alter conserved amino acid residues in two distinct repeats of the structural motif described above. When mutant cDNAs were expressed in NIH-3T3 cells, both mutations severely impaired proteolytic processing of the proreceptor to mature alpha- and beta-subunits. Transport of mutant receptors to the plasma membrane was also impaired. However, the minority (< 10%) of receptors that were eventually transported to the plasma membrane retained the ability to bind insulin with normal affinity and to undergo insulin-stimulated phosphorylation. In conclusion, the effects of these naturally occurring mutations provide experimental support for the importance of the conserved glycine-containing structural motifs described above. By interrupting these structural motifs, the Ala28 and Arg366 mutations prevent normal folding of the insulin receptor alpha-subunit, thereby inhibiting post-translational processing and intracellular transport of the mutant receptors.

Detection of Epstein-Barr virus DNA in Hodgkin- and Reed-Sternberg-cells by single cell PCR

The Epstein-Barr virus (EBV) can be detected in the majority of lymph nodes involved by Hodgkin's lymphoma using the highly sensitive polymerase chain reaction (PCR). However, the rate of EBV-DNA detection by in-situ hybridisation, which allows allocation of EBV to a defined cell population, i.e. the neoplastic H&RS-cells, is lower. In an attempt to combine the advantages of the high sensitivity of the PCR and the possibility of cellular allocation by in-situ hybridisation, we established a single-cell PCR of Hodgkin- and Reed-Sternberg (H&RS)-cells isolated by micromanipulation from biopsy tissues. We amplified EBV sequences from the BamW-region by single-cell PCR. Using this method we were able to detect EBV-DNA in the H&RS-cells from 4 of 6 patients. In EBV positive cases all H&RS-cells of a given patient were positive, proving the high sensitivity and reproducibility of the method. Other cells in the biopsy tissue involved by EBV-positive H&RS-cells were shown to be negative. This indicates that EBV may have a role in the pathogenesis of many but not all cases of Hodgkin's disease.

Ultrastructural localization of the S-100-like proteins MRP8 and MRP14 in monocytes is calcium-dependent

MRP8 and MRP14 are members of the S-100 family of Ca(2+)-binding proteins and are expressed by granulocytes and monocytes. Members of this family have been described to be involved in membrane and cytoskeleton interactions; we therefore studied the subcellular distribution of MRP8/MRP14 in cultured human monocytes at the ultrastructural level. Monospecific rabbit antisera against MRP8 and MRP14 and a monoclonal antibody (moAb 27E10), which exclusively recognizes the MRP8/MRP14 heterodimer but not the monomers, were used in both immunoperoxidase/preembedding- and immunogold/cryotechniques. Comparing non-stimulated monocytes with Ca2+ ionophore A23187-treated cells, we could demonstrate that MRP8 and MRP14 associate with membrane and cytoskeletal structures in a Ca(2+)-dependent manner. Employing moAb 27E10, MRP8/MRP14 complexes were shown to be translocated to these cellular components. In addition, immunogold double-labelling experiments revealed a clear co-localization of MRP8/MRP14 complexes with the type III intermediate filament vimentin. Analysis of immunogold-labelled cryosections of renal allografts after acute vascular rejection demonstrated that a subpopulation of infiltrating macrophages showed a similar association of MRP8/MRP14 to the cytoskeleton in situ; this finding emphasizes the in vivo relevance of our observations. We conclude that Ca(2+)-dependent translocation of MRP8/MRP14 occurs to distinct subcellular components suggesting a role of these proteins for the modulation of cytoskeletal and membrane interactions.

The monoclonal antibody MAC387 detects an epitope on the calcium-binding protein MRP14

The present study was initiated to identify the antigen recognized by the monoclonal antibody (MAb) MAC387 which is widely used for phenotypical characterization of myelomonocytic cells in situ. MAC387 has been described to show a similar reaction pattern as antisera to a complex formed by the calcium-binding proteins MRP8 and MRP14. However, the exact nature of the molecule recognized by MAC387 has been controversial. Using Western blot analysis, MAC387 was found to detect a single protein band of 14 kDa in lysates of human monocytes and granulocytes. Transfection of embryonic lung fibroblasts L132 with either MRP8 or MRP14 cDNA revealed that MAC387 reacts with MRP14 but not MRP8. This finding was confirmed by dot blot analysis of recombinant MRP8 and MRP14. Our data thus provide unequivocal evidence that MAC387 is a monoclonal antibody directed against the calcium-binding protein MRP14.

Antipyresis caused by stimulation of vasopressinergic neurons and intraseptal or systemic infusions of gamma-MSH

Antipyretic properties have been ascribed to arginine vasopressin (AVP), and the site where its antipyretic effects are mediated in the brain was identified as the ventrolateral septum of the limbic system. In guinea pigs, the majority of AVP projections to the septum originate from parvocellular neurons of the hypothalamic paraventricular nucleus (PVN). Electrical stimulation of the PVN with 10-s trains of current pulses (duration 1 ms, frequency 20 Hz, amplitude 8 V, current 0.205 +/- 0.017 mA) reduced the febrile response to an intramuscular injection of 20 micrograms/kg lipopolysaccharide (LPS from Escherichia coli, 0111: B4) by 54% compared with unstimulated animals. This reduction in fever by electrical PVN stimulation was partly reversed by a simultaneous intraseptal microinfusion of the vasopressinergic V1-receptor antagonist d(CH2)5[Tyr(Met)2]AVP at a concentration of 10(-5) mol for 6 h with an infusion speed of 0.1 microliter/min. We further investigated the effects of intraseptal microinfusions or systemic infusions of the gamma-melanocyte-stimulating hormone (gamma-MSH), a derivative of the proopiomelanocortin, on LPS-induced fever. Intraseptal microinfusions of gamma-MSH at a concentration of 10(-5) mol/l for 6 h with an infusion speed of 0.1 microliter/min caused a 38% reduction in fever. A significantly greater 57% reduction in fever was observed when the intraseptal microinfusion of gamma-MSH was combined with electrical stimulation of the PVN (for parameters see above). A systemic infusion of 0.261 mumol gamma-MSH for 6 h reduced LPS fever to approximately 50% compared with animals infused with vehicle (0.9% saline).(ABSTRACT TRUNCATED AT 250 WORDS)

Mutational analysis of the first 14 exons of the adenomatous polyposis coli (APC) gene

In the present study, the polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) technique has been applied to the mutation analysis of the adenomatous polyposis coli (APC) gene. We examined the first 14 exons of the APC gene in 46 polyposis coli patients. Five germline mutations were observed, including a single-nucleotide substitution and small (1-4 bp) deletions leading, in 4 cases, to a stop codon. A missense mutation in exon 3 and a 1 bp deletion in exon 4 of the APC gene were observed in patients presenting with the attenuated form of FAP.