p-Hydroxybenzyl alcohol attenuates learning deficits in the inhibitory avoidance task: involvement of serotonergic and dopaminergic systems

p-Hydroxybenzyl alcohol (HBA), an aglycone of gastrodin, is an active ingredient of Gastrodia elata BLUME. In this study, we investigated the action of HBA on acquisition of an inhibitory avoidance response in rats and used piracetam as a positive control. The results indicated that scopolamine, a cholinergic receptor antagonist, injected before training impaired retention. HBA did not attenuate the scopolamine-induced impairment, but piracetam did. p-Chloroamphetamine, a serotonin releaser, injected before training impaired retention. HBA at 5 mg/kg and piracetam at 100 mg/kg could counteract the p-chloroamphetamine-induced deficit. Apomorphine, a dopaminergic receptor agonist, also impaired retention. HBA at 5 mg/kg and piracetam at 300 mg/kg could ameliorate the apomorphine-induced amnesia. The above results indicated that HBA, different from piracetam, can attenuate impairments induced by p-chloroamphetamine and apomorphine, but had no effect on impairment induced by scopolamine in an inhibitory avoidance task in rats. Such findings suggest that HBA may act through suppressing dopaminergic and serotonergic activities and thus improves learning.

[The effect of anti basic fibroblast growth factor on the development of experimental silicosis bacillus]

Anti-bFGF serum was used to treat rabbit experimental silicosis. At 90 days, when experimental group was compared with control group, the number and size of the nodules in experimental group were much less and smaller than those in control group. Nodules in control group were mainly consist of fibroblast mixed with a small amount of collagen fiber, whereas nodules in experimental group were made up of macrophages. At 180 days, in addition to fibroblasts, there was II to III degree of collagen fiber in nodules of control group. Most of nodules in experimental group mainly contained macrophages. Fibroblasts of lung in fetal mice were cultured in vitro. The results showed that bFGF stimulated proliferation of fibroblast, whereas anti-bFGF serum inhibited fibroblast growth. It appeared that anti-bFGF serum actually blocked proliferation of fibroblast and fibrosis in rabbit experimental silicosis.

Dynamics of human keratin 18 phosphorylation: polarized distribution of phosphorylated keratins in simple epithelial tissues

Phosphorylation of keratin polypeptides 8 and 18 (K8/18) and other intermediate filament proteins results in their reorganization in vitro and in vivo. In order to study functional aspects of human K18 phosphorylation, we generated and purified a polyclonal antibody (termed 3055) that specifically recognizes a major phosphorylation site (ser52) of human K18 but not dephosphorylated K18 or a ser52-->ala K18 mutant. Pulse-chase experiments followed by immunoprecipitation and peptide mapping of in vivo 32PO4-labeled K8/18 indicated that the overall phosphorylation turnover rate is faster for K18 versus K8, and that ser52 of K18 is a highly dynamic phosphorylation site. Isoelectric focusing of 32PO4 labeled K18 followed by immunoblotting with 3055 showed that the major phosphorylated K18 species contain ser52 phosphorylation but that some K18 molecules exist that are preferentially phosphorylated on K18 sites other than ser52. Immunoblotting of total cell lysates obtained from cells at different stages of the cell cycle showed that ser52 phosphorylation increases three to fourfold during the S and G2/M phases of the cell cycle. Immunofluorescence staining of cells at different stages of mitosis, using 3055 or other antibodies that recognize the total keratin pool, resulted in preferential binding of the 3055 antibody to the reorganized keratin fraction. Staining of human tissues or tissues from transgenic mice that express human K18 showed that the phospho-ser52 K18 species are located preferentially in the basolateral and apical domains in the liver and pancreas, respectively, but no preferential localization was noted in other simple epithelial organs examined. Our results support a model whereby phosphorylated intermediate filaments are localized in specific cellular domains depending on the tissue type and site(s) of phosphorylation. In addition, ser52 of human K18 is a highly dynamic phosphorylation site that undergoes modulation during the S and G2/M phases of the cell cycle in association with filament reorganization.

Characterization of a human monoclonal immunoglobulin M (IgM) antibody (IgMBEN) specific for Vi capsular polysaccharide of Salmonella typhi

A search for human monoclonal antibodies to protective antigens of bacteria revealed an immunoglobulin M lambda chain [IgM(lambda); designated IgMBEN] reactive with the Vi capsular polysaccharide of Salmonella typhi. Vi, a linear homopolymer of alpha(1-->4)GalApNAc that is O acetylated at C-3, is a licensed vaccine for typhoid fever. Immunologic properties of IgMBEN were compared to those of burro globulin prepared by intravenous injections of S. typhi (B339-340). IgMBEN and B339-340 yielded identical precipitin lines with Vi by double immunodiffusion. IgMBEN and B339-340 produced similar precipitation results with Vi and its derivatives prepared by de-O-acetylation, carboxyl reduction, and removal or replacement of the N-acetyl at C-2 with O-acetyl. B339-340 yielded maximal precipitation with Vi (0.41 mg of antibody per ml with 1.4 micrograms of Vi); next was carboxyl-reduced, O-acetylated Vi, which precipitated 0.325 mg of antibody per ml with 2.5 micrograms of Vi. IgMBEN yielded maximal precipitation with de-O-acetylated, carboxyl-reduced Vi (approximately 11.0 mg of antibody per ml with approximately 1.3 micrograms of antigen); next were de-O-acetylated Vi (9.89 mg/ml) and Vi (9.19 mg/ml). The precipitin curves and equivalence points of these three antigens were similar. Pneumococcus type 1, which contains GalApNAc, did not precipitate with Vi or its derivatives. These slight differences in specificity between IgMBEN and B339-340 were related to our proposed structure of Vi. We plan to use IgMBEN as a reference for measurement of vaccine-induced Vi antibodies.

Effects of inhibition of nitric oxide formation on the regulation of coronary blood flow in anesthetized dogs

In 11 open-chest dogs with a flowmeter on the left circumflex artery, L-NMMA, a selective inhibitor of nitric oxide-formation, was subselectively infused into the left circumflex artery at a rate of 2.5 mg/ml (ml/min) to avoid systemic hemodynamic effects. The coronary blood flow at normal arterial blood pressure was similar prior to and during L-NMMA infusion. However, when the arterial blood pressure was raised by inflating a balloon in the descending aorta, the nitric oxide suppression induced a dramatic increase in coronary vascular resistance by almost 40% compared to control conditions without L-NMMA infusion at identically elevated arterial blood pressure. L-NMMA induced a significant downward shift and flattening of the pressure-flow relation over a pressure range from 60-150 mmHg. Peak hyperemic coronary flow after 20-s transient coronary occlusion was similar prior to and during L-NMMA infusion, but the duration of the hyperemic flow response was significantly shortened during L-NMMA infusion indicating exaggerated constriction after hyperemic stimulus. The EDRF/nitric oxide-system plays an important role for the regulation of coronary blood flow by counteracting autoregulatory constrictor responses to increased driving pressure and shear stress in the intact canine circulation.

Digital angiographic impulse response analysis of myocardial perfusion: influence of heart rate and blood pressure changes on microcirculatory transit time measurement in the normal canine coronary circulation

The study describes the effect of acute changes in aortic blood pressure and heart rate in the intact normal canine coronary circulation on digital angiographic measurements of the mean transit time of the microcirculation compartment and on direct flow meter measurement of resting and maximal hyperemic coronary blood flow. The mean transit time of the radiographic contrast material through the normal coronary circulation was calculated in 20 dogs by the impulse response analysis from serial digital coronary angiograms under systematically changed blood pressure and heart rate conditions. The mean aortic blood pressure (MAP) was controlled by the inflation of a balloon in the descending aorta (70-150 mmHg). The heart rate was altered by atrial pacing (90, 120, and 150/min). The mean transit times (T mu) of contrast material across the myocardial microcirculation which had been recently shown to correlate with coronary flow reserve (CFR) in stenosed arteries in the canine model were calculated under resting and hyperemic flow conditions from 428 selective coronary angiograms after a hand-injected contrast bolus, T mu was found to be heart rate independent. T mu-1 was linearly correlated with MAP (r = 0.7). There was no difference in T mu under resting and hyperemic flow conditions at comparable MAP. The corresponding distribution volume (V mu) of the microcirculation was calculated as the product of the mean transit time T mu and the measured coronary blood flow. Under resting flow conditions, V mu decreased with rising MAP. Furthermore, V mu increased with rising heart rate, V mu was constant during blood pressure or heart rate changes under hyperemic flow conditions. The data suggest that CFR whether by direct measurements of flow or by radiographic assessment of contrast material kinetics should be standardized with respect to hemodynamic conditions of heart rate and MAP.

Heat stress or rotavirus infection of human epithelial cells generates a distinct hyperphosphorylated form of keratin 8

The two major intermediate filament (IF) phosphoglycoproteins of human simple epithelia are keratins 8 and 18 (K8/18). Previous studies showed that heat stress and, in some cases, viral infection of cultured cells can be associated with alteration in IF organization. Here we show that heat stress of the human colonic cell line HT29 increased K8 and K18 phosphorylation and glycosylation and generated a distinct hyperphosphorylated form of K8 (HK8) that was previously noted upon G2/M arrest of epithelial cells. In contrast, rotavirus infection of HT29 cells resulted in phosphorylation changes similar to those induced by heat stress but did not alter K8/18 glycosylation. The identity of HK8 was determined using phosphatase treatment, tryptic phosphopeptide mapping, and K8-specific antibodies. A time course of heat stress showed that the increased phosphorylation and glycosylation of K8/18 occurred several hours after induction of heat shock protein 70 expression. Rotavirus altered the organization of the K8/18 network in most infected cells, whereas the effect of heat stress on K8/18 organization was less prominent. However, in vitro filament assembly of purified K8/18 was not significantly altered after isolation from heat-stressed or rotavirus-infected cells, despite having increased solubility and hyperphosphorylation. Our results indicate that increased glycosylation and/or phosphorylation of K8 and K18, in association with heat stress or rotavirus infection, does not significantly alter in vitro keratin filament assembly, whereas the association of these modifications with filament reorganization in cells is more dramatic. Generation of HK8 appears to be a late event and to occur in common with several forms of stress including heat, viral infection, and arrest of cells in G2/M.

Successive organophosphate inhibition and oxime reactivation reveals distinct responses of recombinant human cholinesterase variants

To explore the molecular basis of the biochemical differences among acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and their alternative splicing and allelic variants, we investigated the acylation phase of cholinesterase catalysis, using phosphorylation as an analogous reaction. Rate constants for organophosphate (DFP) inactivation, as well as for oxime (PAM)-promoted reactivation, were calculated for antibody-immobilized human cholinesterases produced in Xenopus oocytes from natural and site-directed variants of the corresponding DNA constructs. BuChE displayed inactivation and reactivation rates 200- and 25-fold higher than either product of 3'-variable AChE DNAs, consistent with a putative in vivo function for BuChE as a detoxifier that protects AChE from inactivation. Chimeric substitution of active site gorge-lining residues in BuChE with the more anionic and aromatic residues of AChE, reduced inactivation 60-fold but reactivation only 4-fold, and the rate-limiting step of its catalysis appeared to be deacylation. In contrast, a positive charge at the acyl-binding site of BuChE decreased inactivation 8-fold and reactivation 30-fold. Finally, substitution of Asp70 by glycine, as in the natural 'atypical' BuChE variant, did not change the inactivation rate yet reduced reactivation 4-fold. Thus, a combination of electrostatic active site charges with aromatic residue differences at the gorge lining can explain the biochemical distinction between AChE and BuChE. Also, gorge-lining residues, including Asp70, appear to affect the deacylation step of catalysis by BuChE. Individuals carrying the 'atypical' BuChE allele may hence be unresponsive to oxime reactivation therapy following organophosphate poisoning.

An empirical Bayes approach to smoothing in backcalculation of HIV infection rates

Backcalculation is a methodology to reconstruct the past human immunodeficiency virus (HIV) infection rates from the AIDS incidence data and incubation distribution by deconvolution. Smoothing has proved important in backcalculation, and a key question is how to choose the amount of smoothing. This paper proposes an empirical Bayes approach in which the smoothing parameter is estimated from the data. We introduce a family of priors that reflect the notion of closeness of neighboring infection rates. The variance parameter in the prior family plays the role of the smoothing parameter and is estimated by a method similar to the residual maximum likelihood in linear random effects model through an efficient EM (expectation/maximization) algorithm. A number of penalized likelihood functions that have been used in backcalculation have an empirical Bayes formulation. A bootstrap confidence interval for the infection rates is proposed. The methodology is illustrated with United States AIDS incidence data.

Position-independent expression of whey acidic protein transgenes

The expression of a 3-kilobase genomic rat whey acidic protein (WAP) clone (-949/+2020) in transgenic mice has been demonstrated previously to be copy number-dependent and independent of the site of integration (Dale, T., Krnacik, M. J., Schmidhauser, C., Yang, C. Q.-L., Bissell, M. J., and Rosen, J. M. (1992) Mol. Cell. Biol. 12, 905-914). The present study demonstrated that position-independent expression of the rat WAP -949/+2020 transgene was dependent on transgene spacing. Position-independent expression also was inhibited by an internal replacement of 49 base pair within the conserved GC-rich 3'-untranslated region (3'-UTR) with an identically sized nonspecific DNA sequence. Using electrophoretic mobility shift assays, nuclear factors isolated from mouse and human cells were shown to associate specifically with the rWAP 3'-UTR DNA, but not with the 3'-UTR containing the internal replacement or specific point mutations. Since a single copy of the 3'-UTR inserted 5' of the promoter could not rescue the 3'-UTR deletion, the 3'-UTR element does not appear to be functioning as either a classic enhancer or insulator element. However, the level of expression of rWAP transgenes was correlated with transgene association with the chromosomal scaffold in vivo.

Role of epinephrine in TNF and IL-6 production from isolated perfused rat liver

A bidirectional communication exists between the nervous system and the immune system. Evidence has accumulated suggesting that cytokines-immune peptides influence sympathetic neuronal survival and that cytokines can promote the secretion of catecholamines. Using an isolated perfused rat liver (IPRL) preparation, we have shown that the liver is an important source of circulating cytokines in response to lipopolysaccharide (LPS) and that corticosterone dose dependently influenced LPS-induced production of tumor necrosis factor (TNF) and interleukin-6 (IL-6). In this study, we investigated the direct effect of epinephrine (another stress hormone) on the production of TNF and IL-6 in liver. We demonstrated that epinephrine (1 microM/ml) alone did not induce TNF bioactivity but significantly increased IL-6 bioactivity from IPRL effluent. When the IPRL was infused with LPS, epinephrine significantly decreased TNF bioactivity. Epinephrine in LPS-treated livers also significantly increased IL-6 bioactivity. Both responses were totally inhibited by the beta-blocker propranolol (10 microM/ml). Anisomycin, a protein synthesis inhibitor, infused into the IPRL completely blocked the rise in TNF and IL-6 concentrations in the effluent leaving the IPRL, supporting the hypothesis that the synthesis (or release) of these cytokines was dependent on protein synthesis. We then attempted to determine whether epinephrine exerts similar effects in vitro. Using isolated Kupffer cells and hepatocytes, we found that epinephrine alone had no effect on TNF and IL-6 production in Kupffer cells and hepatocytes but significantly decreased LPS-induced TNF bioactivity and increased LPS-induced IL-6 bioactivity in Kupffer cells. Our data support the hypothesis that epinephrine can promote IL-6 secretion from IPRL.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of corticosterone in TNF and IL-6 production in isolated perfused rat liver

Using an isolated perfused rat liver (IPRL) preparation, we assessed whether corticosterone may contribute to the rise in tumor necrosis factor (TNF) and interleukin-6 (IL-6) in rats after injection with lipopolysaccharide (LPS) or exposure to psychological stress. Intravenous infusion of LPS into the IPRL led to dose-dependent increases in TNF and IL-6 concentrations in the effluent. Anisomycin, a protein synthesis inhibitor, completely blocked the rise in TNF and IL-6 concentration in the IPRL effluent, supporting the hypothesis that the synthesis (or release) of these cytokines was dependent on protein synthesis. Intravenous infusion of corticosterone at nonstressed (35 ng/ml) and stressed levels (350 ng/ml) increased TNF and/or IL-6 release. However, when LPS was combined with corticosterone, the lower dose of corticosterone facilitated the release of cytokines, whereas the higher dose of corticosterone suppressed the release of cytokines. We then showed that isolated Kupffer cells were capable of significant TNF and IL-6 production and that corticosterone decreased LPS-induced cytokine production in these cells. Our data support the hypothesis that the liver is an important source of circulating cytokines in response to LPS. In addition, although in vitro data generally support the hypothesis that corticosterone suppresses the production of cytokines, our in situ data support the hypothesis that physiological levels of corticosterone cause an increase in TNF and IL-6.

The 70-kDa heat shock proteins associate with glandular intermediate filaments in an ATP-dependent manner

Keratin polypeptides 8 and 18 (K8/18) are intermediate filament proteins expressed preferentially in glandular epithelia. We describe the identification, by co-immunoprecipitation from normal human colonic tissues and cultured cell lines, of the 70-kDa heat shock protein (hsp) and its related heat shock cognate protein as K8/18-associated proteins (hsp/c). The association is significant but sub-stoichiometric and occurs preferentially with the soluble rather than the cytoskeletal K8/18 fractions. Heat stress increases the level of soluble K8/18 in association with an increase in hsp70 levels and an increase in the stoichiometry of K8/18-hsp70 association. Identity of the associated proteins was confirmed by microsequencing of a tryptic digest of the purified associated protein and by using anti-hsp/c70-specific antibodies. The K8/18-hsp/c70 complex can be dissociated in a Mg-ATP-dependent manner that requires ATP hydrolysis. Binding of hsp to K8/18 can be reconstituted using purified bovine hsp70 and human K8/18 immunoprecipitates that have been depleted of bound hsp/c70 and increases slightly in the presence of ATP. The reconstituted K8/18-hsp70 complex can be again released in the presence of Mg-ATP. In addition, hsp70 binds to K8/18 without having a significant effect on in vitro filament assembly when added during or after assembly. Using an overlay assay, hsp70 binds exclusively to K8 in the presence of ATP. Our results show direct association of the hsp/c70 proteins with K8/18. This interaction may serve, at least in part, to regulate the function of these two abundant protein groups.

Empigen BB: a useful detergent for solubilization and biochemical analysis of keratins

Intermediate filament (IF) proteins make up some of the most insoluble proteins known, and within the IF protein family, keratins are the least soluble. We compared the efficiency of nonionic, cationic, mixed nonionic and anionic, and zwitterionic detergents in solubilizing keratins from insect cells that express recombinant human keratins and from human colonic cell lines and normal keratinocytes. The cationic detergent cetyltrimethylammonium bromide was similar to the zwitterionic detergent Empigen BB in its ability to efficiently solubilize keratins, but the latter detergent was superior in that it maintained antibody reactivity and allowed for immunoprecipitation of the keratins. Although Nonidet-P40 partially solubilizes keratins, Empigen BB solubilizes a significant amount of keratins not solubilized by Nonidet-P40. In the case of vimentin, differences in solubilization efficiency among the detergents was not as dramatic as with keratins. Our results show that Empigen BB solubilizes a significant amount of epidermal and glandular keratins while preserving antigenicity. This detergent should prove useful for carrying out biochemical and molecular studies on these proteins and may be similarly beneficial for other IF proteins.

Assessing horizontal transfer of nifHDK genes in eubacteria: nucleotide sequence of nifK from Frankia strain HFPCcI3

The structural genes for nitrogenase, nifK, nifD, and nifH, are crucial for nitrogen fixation. Previous phylogenetic analysis of the amino acid sequence of nifH suggested that this gene had been horizontally transferred from a proteobacterium to the gram-positive/cyanobacterial clade, although the confounding effects of paralogous comparisons made interpretation of the data difficult. An additional test of nif gene horizontal transfer using nifD was made, but the NifD phylogeny lacked resolution. Here nif gene phylogeny is addressed with a phylogenetic analysis of a third and longer nif gene, nifK. As part of the study, the nifK gene of the key taxon Frankia was sequenced. Parsimony and some distance analyses of the nifK amino acid sequences provide support for vertical descent of nifK, but other distance trees provide support for the lateral transfer of the gene. Bootstrap support was found for both hypotheses in all trees; the nifK data do not definitively favor one or the other hypothesis. A parsimony analysis of NifH provides support for horizontal transfer in accord with previous reports, although bootstrap analysis also shows some support for vertical descent of the orthologous nifH genes. A wider sampling of taxa and more sophisticated methods of phylogenetic inference are needed to understand the evolution of nif genes. The nif genes may also be powerful phylogenetic tools. If nifK evolved by vertical descent, it provides strong evidence that the cyanobacteria and proteobacteria are sister groups to the exclusion of the firmicutes, whereas 16S rRNA sequences are unable to resolve the relationships of these three major eubacterial lineages.

Wavelet filter evaluation for image compression

Choice of filter bank in wavelet compression is a critical issue that affects image quality as well as system design. Although regularity is sometimes used in filter evaluation, its success at predicting compression performance is only partial. A more reliable evaluation can be obtained by considering an L-level synthesis/analysis system as a single-input, single-output, linear shift-variant system with a response that varies according to the input location module (2(L),2(L)). By characterizing a filter bank according to its impulse response and step response in addition to regularity, we obtain reliable and relevant (for image coding) filter evaluation metrics. Using this approach, we have evaluated all possible reasonably short (less than 36 taps in the synthesis/analysis pair) minimum-order biorthogonal wavelet filter banks. Of this group of over 4300 candidate filter banks, we have selected and present here the filters best suited to image compression. While some of these filters have been published previously, others are new and have properties that make them attractive in system design.

Characterization of salt-soluble forms of acetylcholinesterase from bovine brain

The hydrophilic, salt-soluble (SS) form of acetylcholinesterase (AChE) from bovine brain caudate nucleus exists mainly as a tetramer sedimenting at 10.3S (approximately 40%), and a monomer sedimenting at 3.4S (approximately 60%). The enzyme is N-glycosylated and contains similar HNK-1 carbohydrates as detergent-soluble (DS) AChE. No O-linked carbohydrates could be detected. Amino acid sequencing showed that the N terminus of SS-AChE is identical to that of DS-AChE. In tetrameric SS-AChE, two pairs of disulfide-linked dimers are associated by hydrophobic forces located in the C terminus. Antibodies were raised against a peptide identical to the last 10 amino acid residues of bovine brain DS-AChE. The peptide included the sequence of residues 574-583 (H-Tyr-Ser-Lys-Gln-Asp-Arg-Cys-Ser- Asp-Leu-OH) of the enzyme. The antibodies cross-reacted with tetrameric, but not with monomeric, SS-AChE, showing that in the latter form, the C terminus is truncated. Limited proteolysis of tetrameric SS-AChE at the C terminus led to the formation of an enzymatically active monomer, which did not react with anti-C-terminal antibody. Although the DS form of AChE contains a structural subunit that serves as membrane anchor, no anchor was detected in SS-AChE. Enzyme antigen immunoassays showed that SS-AChE reacted with all monoclonal antibodies directed against the catalytic subunit of DS-AChE, but not with monoclonal antibodies targeting the membrane-anchored subunits. From our results, we conclude that SS-AChE utilizes the same alternative splicing pattern as DS-AChE, leading to tetrameric SS-AChE devoid of the membrane anchor.(ABSTRACT TRUNCATED AT 250 WORDS)

[Chemical constituents of Corydalis decumbens (Thunb.) Pers]

Six compounds were isolated from the quaternary ammoruinn parts of the bulbs of Corydalis decumbenbs in Shangrao District. The structures of menisperine and ferulic acid obtained for the first time from this plant were identified. Other compounds were found identical with the literature so far reported.

Overexpressed monomeric human acetylcholinesterase induces subtle ultrastructural modifications in developing neuromuscular junctions of Xenopus laevis embryos

Formation of a functional neuromuscular junction (NMJ) involves the biosynthesis and transport of numerous muscle-specific proteins, among them the acetylcholine-hydrolyzing enzyme acetylcholinesterase (AChE). To study the mechanisms underlying this process, we have expressed DNA encoding human AChE downstream of the cytomegalovirus promoter in oocytes and developing embryos of Xenopus laevis. Recombinant human AChE (rHAChE) produced in Xenopus was biochemically and immunochemically indistinguishable from native human AChE but clearly distinguished from the endogenous frog enzyme. In microinjected embryos, high levels of catalytically active rHAChE induced a transient state of over-expression that persisted for at least 4 days postfertilization. rHAChE appeared exclusively as nonassembled monomers in embryos at times when endogenous Xenopus AChE displayed complex oligomeric assembly. Nonetheless, cell-associated rHAChE accumulated in myotomes of 2- and 3-day-old embryos within the same subcellular compartments as native Xenopus AChE. NMJs from 3-day-old DNA-injected embryos displayed fourfold or greater overexpression of AChE, a 30% increase in postsynaptic membrane length, and increased folding of the postsynaptic membrane. These findings indicate that an evolutionarily conserved property directs the intracellular trafficking and synaptic targeting of AChE in muscle and support a role for AChE in vertebrate synaptogenesis.

The membrane form of acetylcholinesterase from rat brain contains a 20 kDa hydrophobic anchor

Rat brain acetylcholinesterase (AChE, EC 3.1.1.7) consists of about 80% amphiphilic detergent-soluble (DS-) AChE and 20% hydrophilic salt-soluble (SS-) AChE. DS-AChE contains about 65% tetrameric, 20% dimeric and 10% monomeric, SS-AChE about 40% tetrameric and 60% monomeric forms. N-terminal sequencing of DS- and SS-AChE gave identical N-termini corresponding to the published cDNA sequence of the mature enzyme. The band pattern on SDS-gels is similar to that of AChE from human and bovine brain. SDS-PAGE of hydrophobically labeled DS-AChE revealed the presence of a disulfide bonded hydrophobic membrane anchor of about 20 kDa. Monoclonal antibodies (mAbs) recognizing the anchor-containing subunits of mammalian brain DS-AChE, crossreacted with rat brain DS-AChE but not with SS-AChE. DS- and SS-AChE also reacted with antibodies raised against a peptide comprising the last 10 amino acids of the sequence of bovine brain AChE. Our results led us to conclude that both DS- and SS-AChE from rat brain contain T-type catalytic subunits, and DS-AChE in addition a P-type hydrophobic anchor similar to other mammalian brain DS-AChE.

Subunit association and glycosylation of acetylcholinesterase from monkey brain

Cercopithecus monkey brain acetylcholinesterase (AChE; EC 3.1.1.7) consists of about 15% hydrophilic, salt-soluble enzyme and 83% amphiphilic, detergent-soluble enzyme. Sucrose density gradient centrifugation showed that hydrophilic, salt-soluble AChE was composed of about 85% tetramer (10.3S) and 15% monomer (3.3S). In amphiphilic, detergent-soluble AChE, 85% tetramer (9.7S), 10% dimer (5.7S), and 5% monomer (3.2S) were seen. The enzyme is N-glycosylated, and no O-linked carbohydrate could be detected. Use of two monoclonal antibodies, one directed against the catalytic subunit and the other against the hydrophobic anchor, gave new insights into the subunit assembly of brain AChE. It is shown that in tetrameric AChE, not all of the subunits are disulfide-bonded and that two populations of tetramers exist, one carrying one and the other carrying two hydrophobic anchors.

Monoclonal antibodies against brain acetylcholinesterases which recognize the subunits bearing the hydrophobic anchor

Monoclonal antibodies were raised against amphiphilic detergent-soluble (DS) acetylcholinesterase (AChE) from human brain caudate nucleus. Three mAb, 132-4 (IgG1), 132-5 (IgG1) and 132-6 (IgG3), specific for brain DS-AChE were selected and subcloned. These mAb reacted with native as well as heat-denatured and SDS-denatured DS-AChE, indicating that the epitopes to which mAb bound are continuous determinants. The mAb cross-reacted with DS-AChE from bovine and mouse brain and with brain DS-AChE from river trout (Salmo trutta forma fario) and lake trout (Salmo trutta forma lacustris). No cross-reaction was detected with the following antigens: salt-soluble (SS) AChE from bovine brain, glycophospholipid-anchored AChE from human and bovine erythrocytes, DS-butyrylcholinesterase and SS-butyrylcholinesterase (BtChE) from the brains of human and bovine, DS-BtChE from chicken and BtChE from human serum. Deglycosylation of brain DS-AChE with N-glycosidase F did not abolish the binding of mAb to DS-AChE. After reduction of brain DS-AChE by dithiothreitol, the mAb no longer reacted with the antigen, indicating that a disulfide bridge is important for the epitope. Monomerization of brain DS-AChE by trypsin and limited proteinase K treatment also abolished the binding of mAb to DS-AChE. Sucrose-density-gradient centrifugation showed that mAb reacted only with native tetrameric forms, but not with dimeric and monomeric forms. Western blot, after SDS/PAGE under non-reducing conditions, showed that mAb reacted with those subunits carrying the hydrophobic anchor (i.e. tetramers, trimers and heavy dimers) but not with those devoid of it (light dimers or monomers). Since mAb 132-4, 132-5 and 132-6 recognized DS-AChE from fish up to mammalian brain in the evolutionary tree, it is concluded that the epitope to which these mAb bind, is conserved in nature.

Direct Imaging of the Diacetylene Solid-State Monomer-Polymer Phase Transformation

The solid-state phase transformation from 1,6-di(N-carbazolyl)-2-4-hexadiyne (DCHD) diacetylene monomer to polymer has been studied dynamically by low-dose selected area electron diffraction and high-resolution electron microscopy. The total exposure required to induce polymerization is five orders of magnitude smaller than the critical dose for electron beam damage. The phase transformation is quasi-homogeneous, with the lattice parameters changing continuously as a function of beam dose. Characteristic streaking that develops in the selected area electron diffraction patterns in the [200] reciprocal directions during the intermediate stages of the transformation provides information about the defect-mediated mechanisms of this reaction.

A monoclonal IgM kappa from a blood group B individual with specificity for alpha-galactosyl epitopes on partially hydrolyzed blood group B substance

We have characterized a human monoclonal IgM kappa, designated IgMDON, from a blood group B individual. IgMDON is specific for alpha-galactosyl residues on blood group B substance; its fine specificity as defined by hemagglutination, quantitative precipitin, and inhibition ELISA assays was for the defucosylated terminal Gal(alpha 1-3)Gal epitope. Gal(alpha 1-3)Gal epitopes are also found on a variety of normal and pathogenic intestinal bacteria, and polyclonal IgG antibodies with the same specificity are found in the serum of nearly all normal individuals. The specificity of IgMDON was also quite similar to that of a human antiserum, serum 262, obtained by immunizing an individual with blood group B substance that had been subjected to mild acid hydrolysis (BP1). The possible ways whereby IgMDON might have arisen are discussed.

Variable region cDNA sequences of three mouse monoclonal anti-idiotypic antibodies specific for anti-alpha(1----6)dextrans with groove- or cavity-type combining sites

The variables regions of three syngeneic anti-idiotypic antibodies (Ab2s) were cloned and sequenced. They are encoded by different VL genes, two are from different members of V kappa-Ox1 superfamily. The H chains are encoded by VH genes belonging to three different VH families, J558, Q52 and 7183. Together with a previous report from this laboratory, the nucleotide sequences of four Ab2s to anti-alpha(1----6)dextrans have been presented. They are derived from a number of unrelated germline genes, and differ from similar studies in anti-NP, anti-GAT and anti-Ars systems. Three of four Ab2s in the anti-alpha(1----6)dextran system appear to have D-D fusions, which has also been reported in several other Ab2s.

Different glycosylation in acetylcholinesterases from mammalian brain and erythrocytes

Acetylcholinesterases (EC 3.1.1.7, AChE) have varying amounts of carbohydrates attached to the core protein. Sequence analysis of the known primary structures gives evidence for several asparagine-linked carbohydrates. From the differences in molecular mass determined on sodium dodecyl sulfate-polyacrylamide gel before and after deglycosylation with N-glycosidase F (EC 3.2.2.18), it is seen that dimeric AChE from red cell membranes is more heavily glycosylated than the tetrameric brain enzyme. Furthermore, dimeric and tetrameric forms of bovine AChE are more heavily glycosylated than the corresponding human enzymes. Monoclonal antibodies 2E6, 1H11, and 2G8 raised against detergent-soluble AChE from electric organs of Torpedo nacline timilei as well as Elec-39 raised against AChE from Electrophorus electricus cross-reacted with AChE from bovine and human brain but not with AChE from erythrocytes. Treatment of the enzyme with N-glycosidase F abolished binding of monoclonal antibodies, suggesting that the epitope, or part of it, consists of N-linked carbohydrates. Analysis of N-acetylglucosamine sugars revealed the presence of N-acetylglucosamine in all forms of cholinesterases investigated, giving evidence for N-linked glycosylation. On the other hand, N-acetylgalactosamine was not found in AChE from human and bovine brain or in butyrylcholinesterase (EC 3.1.1.8) from human serum, indicating that these forms of cholinesterase did not contain O-linked carbohydrates. Despite the notion that within one species, the different forms of AChE arise from one gene by different splicing, our present results show that dimeric erythrocyte and tetrameric brain AChE must undergo different postsynthetic modifications leading to differences in their glycosylation patterns.

The monoclonal antibody 2G8 is carbohydrate-specific and distinguishes between different forms of vertebrate cholinesterases

The monoclonal antibody (mAb) 2G8 (subclass IgG2a) raised against acetylcholinesterase (AChE, EC 3.1.1.7) from electric organ of Torpedo nacline timilei crossreacted with AChE from Torpedo marmorata, electric eel (Electrophorus electricus), flounder (Platichthys flesus) body muscle, rat brain, bovine brain, and human brain, this suggests that the epitope to which mAb 2G8 bound had been highly conserved during evolution. No crossreaction was found with AChE from human and bovine erythrocytes, nor with butyrylcholinesterase (BtChE, EC 3.1.1.8) from human serum. Binding of mAb 2G8 to the globular G2 form of AChE from T. marmorata strongly decreased enzyme activity, while no significant inhibition was found with either collagen-tailed, asymmetric forms, or with the enzymes from flounder body muscle or mammalian sources. The possibility that mAb 2G8 bound to anionic sites of AChE could be excluded since neither edrophonium chloride nor decamethonium bromide influenced the binding of 2G8 to the enzymes. Enzyme-linked immunosorbent assay and Western blot showed that heat-denatured, diisopropylfluorophosphate-treated, CNBr- and trypsin-digested AChE from T. marmorata still reacted with mAb 2G8; this indicates that the epitope to which 2G8 bound, at least partially, belonged to a continuous determinant. Treatment of cholinesterases with N-glycosidase F abolished crossreaction with 2G8, showing that an essential part of the epitope consisted of N-linked carbohydrates.

The vitamin D-responsive element in the human osteocalcin gene. Association with a nuclear proto-oncogene enhancer

A vitamin D-responsive element (VDRE) locus within the 5' region of the human osteocalcin gene promoter contains a steroid response-like half-site immediately proximal to a consensus site for the AP-1 nuclear oncogene family. In the studies described here, internal mutagenesis of the osteocalcin promoter coupled to functional assays reveal that the interaction of the vitamin D receptor is limited to the proximal region of the VDRE locus. Mutations within the distal AP-1 consensus site reduce the basal activity of the promoter but have little effect on vitamin D inducibility. The absolute level of promoter activity induced by hormone, however, is dramatically reduced in the absence of an intact AP-1 site suggesting a functional synergism between the receptor and AP-1-related proteins. In vitro receptor-DNA binding studies confirm the lack of requirement for the distal component in receptor binding. These results suggest that the osteocalcin VDRE is limited to 15 nucleotides closely juxtaposed to a distal functional AP-1 site. The close association of the two sites may lead to proto-oncogene and steroid receptor interactions that result in interesting functional consequences.

Vitamin D receptor interaction with specific DNA requires a nuclear protein and 1,25-dihydroxyvitamin D3

The regulation of osteocalcin gene expression by 1,25-dihydroxyvitamin D3 is mediated by the vitamin D receptor and a cis-acting DNA response element that has been identified within the 5' region of the osteocalcin promoter. In this report, we show that vitamin D receptors derived from nuclear extracts of mammalian cells bind directly to this cis-acting element in vitro and do so in a manner requiring hormone. Vitamin D receptors derived from reticulocyte lysate translations in vitro or from extracts of a Saccharomyces cerevisiae strain that expresses the recombinant protein also bind the osteocalcin responsive element, but only when nuclear extracts of mammalian cells are provided. The vitamin-D-receptor-DNA-binding accessory factor is isolated by salt extraction, labile to temperature, and sensitive to tryptic digestion. These studies suggest that the high-affinity interaction of the vitamin D receptor with the osteocalcin vitamin D response element in vitro requires both 1,25-dihydroxyvitamin D3 and an accessory protein derived from the mammalian cell nucleus.

Two families of monoclonal antibodies to alpha(1----6)dextran, VH19.1.2 and VH9.14.7, show distinct patterns of J kappa and JH minigene usage and amino acid substitutions in CDR3

Nine groove-type mAb to alpha(1----6)dextran were cloned and sequenced. Together with previous reports from this laboratory, the VH and VL of 34 mAb have been sequenced, in which 10 VH19.1.2 and 11 VH9.14.7 combined with the V kappa-Ox1 gene to form two major families of anti-alpha(1----6)dextrans. The same D minigene (DFL16) was used by all VH19.1.2 and VH9.14.7 mAb; however, the patterns of JH and J kappa usage are quite different. VH19.1.2 mAb used only JH3 and J kappa 2, whereas VH9.14.7 mAb used three JH (JH1, JH2, and JH3) and all four active J kappa (J kappa 1, J kappa 2, J kappa 4, and J kappa 5). Relative uniformity in the lengths of VH CDR3 and the junctional sequences is seen in both families. Some mAb from different mouse strains share common structural features. The differences in idiotypic specificities and in the amino acid sequences suggest that VH19.1.2 and VH9.14.7 may differ in the conformation of CDR1 and CDR2. Combining with V kappa-Ox1 gene to generate groove-type combining sites to the single site-filling epitope of alpha(1----6)dextran, the two VH chains may require certain conformations of CDR3. Whether such conformational requirements influence the choice of J minigenes, the selection of the length of VH CDR3 and the sequences at junctions, are discussed.

Two families of monoclonal antibodies to alpha(1----6)dextran, VH19.1.2 and VH9.14.7, show distinct patterns of J kappa and JH minigene usage and amino acid substitutions in CDR3

Nine groove-type mAb to alpha(1----6)dextran were cloned and sequenced. Together with previous reports from this laboratory, the VH and VL of 34 mAb have been sequenced, in which 10 VH19.1.2 and 11 VH9.14.7 combined with the V kappa-Ox1 gene to form two major families of anti-alpha(1----6)dextrans. The same D minigene (DFL16) was used by all VH19.1.2 and VH9.14.7 mAb; however, the patterns of JH and J kappa usage are quite different. VH19.1.2 mAb used only JH3 and J kappa 2, whereas VH9.14.7 mAb used three JH (JH1, JH2, and JH3) and all four active J kappa (J kappa 1, J kappa 2, J kappa 4, and J kappa 5). Relative uniformity in the lengths of VH CDR3 and the junctional sequences is seen in both families. Some mAb from different mouse strains share common structural features. The differences in idiotypic specificities and in the amino acid sequences suggest that VH19.1.2 and VH9.14.7 may differ in the conformation of CDR1 and CDR2. Combining with V kappa-Ox1 gene to generate groove-type combining sites to the single site-filling epitope of alpha(1----6)dextran, the two VH chains may require certain conformations of CDR3. Whether such conformational requirements influence the choice of J minigenes, the selection of the length of VH CDR3 and the sequences at junctions, are discussed.

[Detection of the anti-cancer biological effect of naphthoquinone pigment-LIII]

Naphthoquinone pigment-LIII, an extract from Arnebia euchroma, could apparently inhibit the proliferation of stomach cancer cell line and esophagus cancer cell line. At the effective concentration of 5 micrograms/ml, the mitotic index and growth curve declined without showing any damage to human normal cells. At 5-10 micrograms/ml, the colony efficiency of cancer cells became significantly low. The anti-cancer effect of Naphthoquinone pigment-LIII might be related to its role of influencing the amount of RNA and ultrastructure of cancer cells which was discussed in this paper.

[Use of intraspinal narcotics in obstetric anesthesia and analgesia]

The use of intraspinal narcotics has attracted great interest worldwide, particularly in the discipline of obstetric anesthesia. As the advent of spinal and epidural local anesthetics dramatically effected the anesthetic management of labor, delivery and obstetric surgery, likewise spinally administered opioids are emerging as safe and very effective methods of relieving post-cesarean section pain, improving labor and cesarean section analgesia in combination with local anesthetics, and injected alone in the subarachnoid space for the management of labor itself. Though intraspinal narcotic analgesia is associated with a number of side effects, with proper knowledge these adverse reactions are wither preventable or can be greatly reduced. Compared to the benefits of nearly complete pain relief in the intrapartum and postpartum periods, the price paid in terms of these side effects in minimal. The review was based on a computer-assisted search for articles published after 1975.

[Rules for differentiating symptoms and signs of the heart-qi deficiency syndrome]

344 cases of Heart-Qi Deficiency Syndrome (HQDS) including 19 Kinds of disease were observed to explore the rule of differentiation of symptoms and signs for HQDS. The results showed that the common symptoms of HQDS were weakness, shortness of breath, and palpitation, etc. According to with or without complicated cardiovascular diseases, the patients were divided into two groups: group A with cardiovascular diseases, group B without that. In group A, the symptoms and signs of HQDS were the most frequent and early clinical manifestations, the associated symptoms and signs were blood stasis and attack of water-evil, etc. In group B, in whom often associated with nervous and emotional symptoms such as insomnia, dreamfulness, and amnesia, etc., which was due to the disturbance of emotional activities of heart. In order to avoid diagnostic confusion, the authors suggest that the HQDS patients with cardiovascular diseases would be diagnosed as HQDS; on the other hand, the HQDS patients without cardiovascular diseases would be diagnosed as disturbance of emotional activities of heart.

[A serological survey of Legionnaires' disease in domestic fowls and animals in Chengdu area]

A serological survey of antibodies against Legionella pneumophila (Lp) serotypes in Chengdu area by microagglutination test showed that there were high levels of antibodies against serotypes Lp1 and Lp6 in healthy domestic fowls and animals (rabbits, pigs, chickens, ducks and geese). In rabbits, antibodies against serotypes Lp1-Lp6 were determined, showing positive rates (titer greater than or equal to 1:16) ranging 6.3-23.8%. Among them only the serotype Lp3 did not show any positive one. The highest positive rate was observed in pigs' anti-Lp6 (89.8%), significantly higher than those reported in America, Denmark and Nanjing, China. The results suggested that recessive infections of Legionnaires' Disease Bacterium might occur in domestic fowls and animals. So the epidemiological surveillance of Legionnaires' disease in animals, as well as in environment (water and soil) is of importance for the prevention in man.

[A study of acute toxicity of mitoxantrone]

Acute toxicity of mitoxantrone (DHAQ) synthetized by Department of Organic Chemistry, School of Pharmacy, WCUMS was studied in mice and dogs. The toxic effects were compared with those of adriamycin (ADR). The LD50 were 6.6 +/- 1.3 and 7.1 +/- 1.6 mg/kg DHAQ, 7.9 +/- 2.1 and 10.7 +/- 2.2 mg/kg ADR (P = 0.95) respectively on observation with a single dose i.v. and i.p., for 21 days in Kunming mice. The toxicity appeared to be delayed with DHAQ and ADR. The earliest death occurred on 4th day after treatment in mice. In the third week still a few died. There were obvious decreases in WBC counts in the peripheral blood of mice receiving either 1-2.5 mg/kg DHAQ or 2.5-5 mg/kg ADR with a single dose i.p.. The WBC count could return to normality after 3 weeks with the withdrawal of the drugs. On electron microscopic examination of myocardial samples from mice 4 days after a single dose of 20 mg/kg DHAQ i.p., mitochondria swelling and vacuoles formation in some cells were shown. Besides the above-mentioned changes, some myocytes exhibited disorientation and loss of myofilaments in the mice which received equivalent dose of ADR. In dogs anaesthetized a temporary falling of blood pressure and slowing of heart rate were observed following 5-10 mg/kg DHAQ i.p.. When a dose of 50-100 mg/kg was given, the blood pressure dropped continuously until death.

[Changes in the relaxation and compliance of the left ventricle in cardiomyopathy]

In order to study the left ventricular diastolic events in cardiomyopathy, carotid pulse tracing, electrocardiogram, phonocardiogram and apexcardiogram with its first derivatives (dA/dt) were simultaneously recorded in 240 normal subjects, 30 patients with dilated cardiomyopathy (DCM) and 44 patients with hypertrophic cardiomyopathy (HCM). Total relaxation time (TRT), total relaxation time index (TRTI), the ratio of A wave to total diastolic amplitude in apexcardiogram (A/D), diastolic amplitude time index (DATI), the ratio of RF wave in apexcardiogram to the total amplitude of apex tracing (F/H) and the variables reflecting the diastolic properties were measured to evaluate the left ventricular relaxation and compliance. Meanwhile, two variables reflecting the contractile ability of the left ventricle were measured in order to compare with the diastolic events. The results demonstrated that in normal subjects relaxation and compliance of the left ventricle showed a tendency of natural "decay" with aging and in patients with DCM and HCM these were significantly decreased, especially in patients with HCM. A/D, which reflects the left ventricular compliance, was increased in patients with HCM as compared with normal subjects (P less than 0.01) and also with patients with DCM. It means that a greater A/D is in favor of the diagnosis of HCM rather than DCM. In addition to abnormal diastolic events, systolic dysfunction, as evidenced by remarkable abnormalities of the contractile variables (PEP/LVET and R-dA/dt.I), was found as well in patients with DCM.

The epitope associated with the binding of the capsular polysaccharide of the group B meningococcus and of Escherichia coli K1 to a human monoclonal macroglobulin, IgMNOV

The fine structure of the combining site of human mAb IgMNOV to poly-alpha(2----8)linked NeuNAc, the epitope of the group B meningococcal and E. coli K1 polysaccharides, has been probed using RIA and ELISA. Inhibition by oligomers ranging from 2 to 12 residues was used to assay binding to IgMNOV by group B meningococcal polysaccharide preparations (GBMP) or by poly(A). The inhibitory properties of the oligomers were almost identical in both assays of the binding of GBMP to horse IgM (H46). This evidence and the finding that both GBMP and poly(A) precipitated IgMNOV equally per unit weight indicated that the epitope of poly(A) must mimic an equivalent epitope on GBMP despite the absence of any apparent common structural features in the two molecules. Unlike most carbohydrate-anticarbohydrate systems in which the site is saturated by oligomers of up to six or seven sugars, all the anti-alpha(2----8)NeuNAc systems above required much larger oligomers. Because these oligomers are larger than the maximum size of an antibody site the epitope must be conformationally controlled, and this has been confirmed by nuclear magnetic resonance spectroscopy. However, despite the above similarities, GBMP and poly(A) were differentiated in that only GBMP bound to H46. Smaller linear molecules obtained by delipidating the GBMP, as well as periodate-oxidized GBMP with its nonreducing end oxidized or linked covalently to BSA, bound to and precipitated IgMNOV and H46. This showed that, despite their differences, terminal nonreducing ends were not involved and that both epitopes were located in the conformationally controlled inner residues of the GBMP. The difference thus must reside in the ability of IgMNOV and H46 to recognize different structural aspects of the same conformationally controlled inner residues. The ELISA data indicate that both IgMNOV and H46 have groove-type sites that bind exclusively to an epitope located on the acidic side of the inner residues. The differences determining the ability of IgMNOV and the failure of H46 to cross-react with poly(A), poly(I), and denatured DNA, may depend on differences in the degree of protonation required by each antibody, and this may be clarified by a study of the effects of pH on the precipitin behavior of IgMNOV and H46.

Monoclonal IgM with unique specificity to gangliosides GM1 and GD1b and to lacto-N-tetraose associated with human motor neuron disease

IgM lambda monoclonal antibodies in two patients with motor neuron disease showed the same unique antigenic specificity. They bound to gangliosides GM1 and GD1b and to lacto-N-tetraose-BSA. By immunofluorescence microscopy they bound to central and peripheral nerve tissue and to motor end-plates at the neuromuscular junction. Sera from control subjects did not contain antibodies of similar specificity. Monoclonal IgMs with the same unique specificity could be responsible for motor neuron disease in some patients with monoclonal gammopathies.

Purification of membrane proteins in SDS and subsequent renaturation

A prerequisite for the purification of any protein to homogeneity is that the protein is not non-specifically associated with other proteins especially during the final stage(s) of the fractionation procedure. This requirement is not so often fulfilled when nonionic detergents (for instance Triton X-100) are used for solubilization of membrane proteins. The reason is that these detergents are not efficient enough to prevent the protein of interest from forming aggregates with other proteins upon contact with chromatographic or electrophoretic supporting media, which, due to their polymeric nature, have a tendency to induce aggregation of other polymers, for instance, hydrophobic proteins. The aggregation can be avoided if sodium dodecyl sulfate (SDS) is employed as detergent. We therefore suggest that membrane proteins should be purified by conventional methods in the presence of SDS and that the purified proteins, which are in a denatured state, are allowed to renature. There is good change to renature internal membrane proteins since they should not be so susceptible to denaturation by detergents as are water-soluble proteins because the natural milieu of the former proteins is lipids which in fact are detergents. In this paper we present a renaturation method based on the removal of SDS by addition of a large excess of G 3707, a nonionic detergent. By this technique we have renatured a 5'-nucleotidase from Acholeplasma laidlawii and a neuraminidase from influenza virus. The enzyme activities were higher (up to 6-fold) after the removal of SDS than prior to the addition of SDS.

Factors affecting the secretion of submandibular salivary kallikrein in cats

Glandular kallikrein has been assessed in submandibular saliva, homogenates and plasma by the fluorimetric substrate D-Val-Leu-Arg-7-amino-4-trifluoromethylcoumarin (AFC) and histochemically in tissue sections by the 4-methoxy-2-naphthylamide (MNA) analogue. Nerve stimulation was used to produce salivary secretion. Parasympathetic saliva contained low concentrations of kallikrein, independently of any circulating catecholamines from the adrenals. Sympathetic saliva contained very high concentrations of kallikrein; the amounts in individual drops rapidly reached a peak then declined gradually. Adrenergic blocking drugs during mixed parasympathetic and sympathetic stimulation showed that beta-adrenergic effects normally increase the secretion of kallikrein in response to the alpha-adrenergic influence from sympathetic nerve impulses. Small amounts of a glandular kallikrein-like activity are present in the plasma. Effluent blood from the submandibular gland before, during and after stimulation of either nerve gave no indication that submandibular kallikrein passes from the glandular compartment to the blood under conditions of unobstructed salivary flow. Excision of the chorda tympani indicated that parasympathetic nerve impulses are required for the normal resynthesis of submandibular kallikrein. The secretion of salivary kallikrein is essentially an exocrine function but its role in the saliva remains obscure. The results suggest that sudden mobilization of kallikrein may occur at times into the saliva and that a separate population of adrenergic axons, under separate central control, may pass to the striated ducts specially for this purpose.

Different VL and VH germ-line genes are used to produce similar combining sites with specificity for alpha(1----6)dextrans

Monoclonal antibodies to alpha(1----6)dextrans produced in mice immunized with the T-independent antigens alpha(1----6)dextran or the stearylisomaltosyl oligosaccharides have been characterized immunochemically. To correlate the immunochemical properties of these monoclonal antibodies with their primary structure, we have sequenced the variable (V) regions of the light (L) and heavy (H) chains. Three V kappa germ-line genes belonging to two major gene families were used; differential J usages also contribute to diversity. Five different VH germ-line genes belonging to three major VH families were used. The VH genes were further modified by junctional diversity and differential J usage and possibly by somatic mutations. The effects of these modifications on the fine specificities of anti-alpha(1----6)dextrans are discussed. Thus far, six different combinations of VLJL-VH(D)JH chains that form groove-type combining sites specific for alpha(1----6)dextran have been found. We conclude that entirely different VL and VH can form combining sites specific for the internal linear sequence of alpha(1----6)dextran.

Different VL and VH germ-line genes are used to produce similar combining sites with specificity for alpha(1----6)dextrans

Monoclonal antibodies to alpha(1----6)dextrans produced in mice immunized with the T-independent antigens alpha(1----6)dextran or the stearylisomaltosyl oligosaccharides have been characterized immunochemically. To correlate the immunochemical properties of these monoclonal antibodies with their primary structure, we have sequenced the variable (V) regions of the light (L) and heavy (H) chains. Three V kappa germ-line genes belonging to two major gene families were used; differential J usages also contribute to diversity. Five different VH germ-line genes belonging to three major VH families were used. The VH genes were further modified by junctional diversity and differential J usage and possibly by somatic mutations. The effects of these modifications on the fine specificities of anti-alpha(1----6)dextrans are discussed. Thus far, six different combinations of VLJL-VH(D)JH chains that form groove-type combining sites specific for alpha(1----6)dextran have been found. We conclude that entirely different VL and VH can form combining sites specific for the internal linear sequence of alpha(1----6)dextran.

A human monoclonal macroglobulin with specificity for alpha(2----8)-linked poly-N-acetyl neuraminic acid, the capsular polysaccharide of group B meningococci and Escherichia coli K1, which crossreacts with polynucleotides and with denatured DNA

We have described an IgM antibody from a patient with macroglobulinemia specifically reacting with poly-alpha(2----8)N-acetyl neuraminic acid (NeuNAc) the capsular polysaccharide of two important human pathogens, group B meningococcus and E. coli K1. This antibody has a narrowly defined specificity in its interactions with polysaccharides, being unable to bind poly-alpha(2----9)NeuNAc or alternating poly-alpha(2----8)alpha(2----9)NeuNAc. However, it shows interesting crossreactivity with seemingly unrelated polynucleotides and denatured DNA, supporting the hypothesis that charged groups with a given spacing may determine the specificity of antigen-antibody interactions on otherwise dissimilar molecular structures. Despite the crossreactivity with denatured DNA and polynucleotides, the antibody does not appear to have adverse effects in the patient. The antibody protects newborn rats against E. coli K1 infection, as well as the standard horse antiserum H46, and one would expect it to prove useful in humans as an adjunct to antibiotic therapy in infections with group B meningococcus and E. coli K1. We have attempted to clone the antibody-producing cells from peripheral blood, and have shown that the relevant cells are present and can be cultured.