Characterization and localization of the Huntington disease gene product

The recent identification of the Huntington's disease (HD) gene, enabled us to synthesize oligopeptides corresponding with the carboxy-terminal end of the predicted HD-gene (IT15) product. Immunobiochemcial studies with polyclonal antibodies directed against this synthetic peptide (position 3114-3141) on lymphoblastoid cells from normal individuals and patients with Huntington disease, revealed the presence of a protein (huntingtin) with a molecular mass of approximately 330 kDa. Immunocytochemical studies showed a cytoplasmic localization of huntingtin in various cell types including neurons. In most of the neuronal cells the protein was also present in the nucleus. No difference in molecular mass or intracellular localization was found between normal and mutant cells.

Analysis of nucleic acids in purified scrapie prion preparations

Amount, type, and size of nucleic acid molecules associated with purified prion preparations were analyzed. Return refocusing gel electrophoresis (RRGE) was developed to detect homogeneous and heterogeneous nucleic acids extracted from highly purified scrapie prion preparations. With this method all types of nucleic acids in the size range from 13 to several thousand nucleotides could be analyzed. The recovery of all nucleic acids, after deproteinization and two-phase extraction was higher than 90%. Despite extensive nuclease digestions some small polynucleotides remained. Although a scrapie-specific nucleic acid cannot be excluded, the results further define the possible characteristics for such a hypothetical molecule. If it was homogeneous in size, then it would be < 80 nt in length at a particle-to-infectivity ratio (P/I) near unity; if the other extreme, i.e. totally heterogeneous scrapie-specific nucleic acids were assumed, then scrapie-specific nucleic acids would have to include molecules smaller than 240 nt. In order to exclude the possibility that unspecific background nucleic acid is entrapped in prion-rods, infectious material has to be prepared without a proteolysis and rod formation, and the analysis of nucleic acids performed with those preparations.

The limbic system: a review of its empirical foundation

The concept of the limbic system is highly influential in many areas of the neurosciences and in their applications to clinical medicine. The value of this concept has been questioned, denied, and defended several times in the past but a comprehensive critical evaluation has never been published. In this article we take several approaches to analyse empirical data of relevance to the limbic system. First we delineate its factual application in different areas. The limbic system has a very wide scope and divergent use. Secondly we extract criteria for its definition from research literature using the bibliographic database Medline. The limbic system has been defined variously on a number of different descriptive levels from morphology to behaviour. Thirdly we review its empirical foundations comparing evidence from different sources. The limbic system lacks an adequate empirical definition in spite of numerous efforts. Last we evaluate its construction as a scientific concept from empirical facts. The limbic system is a non-empirical explanatory concept for poorly understood brain functions. We conclude that the concept of the limbic system cannot be accepted on empirical grounds. However, it is a very attractive concept in the search for explanation of brain function. The non-empirical contents of the limbic system remains largely unexplored.

Prolactin-induced proliferation of the Nb2 T-lymphoma is associated with protein kinase-C-independent phosphorylation of stathmin

Phosphorylation of stathmin, a 19-kDa protein found in many tissues, has been linked to cell differentiation and proliferation. This protein is present in lymphocytes, and both phosphorylation and expression of stathmin are regulated by lymphotropic agents. In this study an antibody specific for stathmin was used to examine phosphorylation in response to PRL. The results suggest that PRL stimulates stathmin phosphorylation in the Nb2 lymphoma and that phosphorylation correlates with PRL-induced cell proliferation. Stathmin expression does not change substantially as PRL-stimulated Nb2 cells move through the cell cycle and enter into the S-phase. Thus, stathmin phosphorylation, but not expression, is regulated by PRL. Activation of protein kinase-C (PKC) in Nb2 cells also induces phosphorylation of stathmin, but PKC does not appear to mediate phosphorylation in response to PRL. The pattern of phosphorylation in response to 12-O-tetradecanoylphorbol-13-acetate differs from that in response to PRL, and down-regulation of PKC does not inhibit PRL-induced phosphorylation or proliferation. In addition to stathmin, PRL increases phosphorylation of a group of stathmin-like proteins. Phosphorylation of these proteins also correlates well with PRL-induced proliferation. Taken together, the results suggest that phosphorylation of stathmin and stathmin-like proteins may mediate some actions of PRL in Nb2 cells. The results further suggest that activation of PKC is not an important early event in PRL-stimulated mitogenesis in Nb2 cells.

Further analysis of nucleic acids in purified scrapie prion preparations by improved return refocusing gel electrophoresis

Although increasingly unlikely, the possibility of a scrapie-specific nucleic acid carried by infectious prion particles is still unresolved. Return refocusing gel electrophoresis was developed to detect homogeneous and heterogeneous nucleic acids extracted from highly purified scrapie prion preparations. This method was improved with respect to the size range from 13 to 1100 nucleotides (nt) over which analyses could be performed. The yield of nucleic acid, particularly of small DNA oligonucleotides and polyadenylated RNA, was determined after deproteinization and two-phase extraction. Despite extensive nuclease digestions some small polynucleotides remained. Although a scrapie-specific nucleic acid cannot be excluded, the results further define the possible characteristics of a hypothetical molecule. If homogeneous in size, such a molecule would be less than 80 nt in length at a particle-to-infectivity ratio near unity, if heterogeneous, scrapie-specific nucleic acids would have to include molecules smaller than 240 nt.

Gangliosides suppress tumor necrosis factor production in human monocytes

Both normal and malignant cells contain gangliosides as important cell membrane constituents that, after being shed, may influence cells of the immune system. We have studied the impact of gangliosides on the expression of TNF in blood monocytes and in the monocytic cell line Mono Mac 6. Although under standard culture conditions, bovine brain gangliosides (100 micrograms/ml) suppressed LPS-stimulated TNF production 5-fold in PBMC and 10-fold in Mono Mac 6 cells, suppression was more efficient under serum-free conditions. Looking at highly purified gangliosides, GD3, GD1a, GM3, GM2, and GM1 were all effective in reducing TNF production in PBMC, and in Mono Mac 6 by factor 10 to 50. The suppressive activity was lost in molecules, lacking the sugar moiety or the lipid moiety. Gangliosides appear to act at an early step of activation in that TNF transcripts were reduced and the mobilization of the nuclear factor kappa B was blocked. Furthermore, in time kinetics, gangliosides were effective for up to 30 min after addition of LPS, but not thereafter. However, the expression of the CD14 Ag, a receptor molecule for LPS-LPS binding protein complexes, was unaffected by gangliosides. Finally, when using Staphylococcus aureus or platelet activating factor as a stimulus, gangliosides were able to suppress TNF production in Mono Mac 6 cells by factor 5 to 10, as well. On the other hand, phorbol ester-induced production of O2- was similar in cells treated with and without gangliosides. Taken together, our data demonstrate that TNF gene expression in monocytes induced by different types of stimuli can be blocked by gangliosides at an early step of signal transduction.

Gangliosides suppress tumor necrosis factor production in human monocytes

Both normal and malignant cells contain gangliosides as important cell membrane constituents that, after being shed, may influence cells of the immune system. We have studied the impact of gangliosides on the expression of TNF in blood monocytes and in the monocytic cell line Mono Mac 6. Although under standard culture conditions, bovine brain gangliosides (100 micrograms/ml) suppressed LPS-stimulated TNF production 5-fold in PBMC and 10-fold in Mono Mac 6 cells, suppression was more efficient under serum-free conditions. Looking at highly purified gangliosides, GD3, GD1a, GM3, GM2, and GM1 were all effective in reducing TNF production in PBMC, and in Mono Mac 6 by factor 10 to 50. The suppressive activity was lost in molecules, lacking the sugar moiety or the lipid moiety. Gangliosides appear to act at an early step of activation in that TNF transcripts were reduced and the mobilization of the nuclear factor kappa B was blocked. Furthermore, in time kinetics, gangliosides were effective for up to 30 min after addition of LPS, but not thereafter. However, the expression of the CD14 Ag, a receptor molecule for LPS-LPS binding protein complexes, was unaffected by gangliosides. Finally, when using Staphylococcus aureus or platelet activating factor as a stimulus, gangliosides were able to suppress TNF production in Mono Mac 6 cells by factor 5 to 10, as well. On the other hand, phorbol ester-induced production of O2- was similar in cells treated with and without gangliosides. Taken together, our data demonstrate that TNF gene expression in monocytes induced by different types of stimuli can be blocked by gangliosides at an early step of signal transduction.

Search for a putative scrapie genome in purified prion fractions reveals a paucity of nucleic acids

Scrapie can be transmitted by novel infectious pathogens termed prions. No evidence for a scrapie-specific nucleic acid has been detected to date. To investigate amounts, types and sizes of nucleic acid molecules associated with prions in purified preparations, aliquots were deproteinized, and the nucleic acids analysed by PAGE and silver staining. Digestion with nucleases and exposure to Zn2+ prior to analysis substantially diminished the content of nucleic acids, but did not alter the prion titre indicating that those nucleic acids which were removed are not essential for infectivity. Since a single species of scrapie-specific nucleic acid could not be identified, we explored the unprecedented possibility of scrapie-specific nucleic acids of variable length which are biologically active. If such molecules of variable length exist then they might be hidden within the background smear on silver-stained gels after PAGE. A new procedure designated return refocusing gel electrophoresis (RRGE) was developed to identify heterogeneous nucleic acids in purified prion fractions. The content of variable length nucleic acids was reduced by a factor of 10 by exhaustive Bal 31 exonuclease digestion after dispersion of purified prions into detergent-lipid-protein complexes. For example, a typical sample after Bal 31 digestion contained approximately 4 ng of nucleic acid of variable length and 10(8.7) ID50 units of scrapie prion infectivity. Consideration of different models for a hypothetical scrapie-specific nucleic acid suggests that such a molecule would have to be: (i) quite small (less than 100 nucleotides), (ii) possess a particle-to-infectivity ratio near unity or (iii) heterogeneous in size. Although our results do not eliminate the possibility that prions possess a scrapie-specific nucleic acid of variable length, they narrow considerably the spectrum of features specifying such a candidate molecule.

Monocyte phenotype and interleukin-1 production in patients undergoing haemodialysis

The expression of MHC class II (HLA-DR) and complement receptor (CR1) surface molecules on CD 14+ monocytes were compared with the production of the monokine interleukin-1 beta (IL-1 beta) in patients with endstage renal disease undergoing maintenance haemodialysis (HD) with hollow fibre dialyzers containing cellulose (CE, n = 8) and polysulfone (PS, n = 7) membranes. Monocyte staining was performed in blood samples obtained at the beginning and after 3 h of HD. Analysis of surface marker expression was done by immunofluorescence staining and flow cytometry analysis. Specific fluorescence intensity for both CR1 and class II (HLA-DR) antigens was increased in patients treated with CE membranes at the beginning of a dialysis treatment when compared to healthy control values. Interestingly, after 3 h on dialysis a further increase was noted for CR1 complement receptor expression whereas the increased HLA-DR expression was no longer detectable. In contrast, specific fluorescence intensity for both antigens was not significantly different from controls, either before or after dialysis, in patients treated with PS. The capacity of peripheral blood mononuclear cells to produce IL-1 beta spontaneously in vitro in the two patient groups was found to parallel results on phenotypic expression of surface molecules. The present study demonstrates that functional signs of monocyte activation, as evidenced by an augmented IL-1 beta production, in some patients on long-term HD correlate with an increased expression of two functionally important monocyte surface marker molecules.

[Alpha-1 inhibition. Knowledge and prospectives]

Increased vascular peripheral resistances is the most frequent hemodynamic modification found in arterial hypertension. Arterial vasodilators therefore seem to be an appropriate therapeutic mean in this pathology. Alpha inhibitors to which prazosin belongs are potent arterial vasodilators. Prazosin's new galenic form will allow a larger therapeutic field.

Inhibition of lipopolysaccharide-induced in vitro desensitization by interferon-gamma

Exposure of Mono-Mac-6 cells to lipopolysaccharide (LPS) can induce rapid and transient expression of cytokines like tumor necrosis factor (TNF), interleukin 1 and interleukin 6. Preculture of Mono-Mac-6 cells in culture medium containing small amounts (1-50 ng/ml) of LPS for 3 days leads to an unresponsiveness to a subsequent stimulation with a high amount of LPS. This in vitro desensitization of a monocytic cell line may serve as a model for desensitization to LPS seen in vivo, for example in mice or man repetitively treated with LPS. Addition of interferon-gamma (IFN-gamma) to the Mono-Mac-6 cells during the LPS preculture period leads to an inhibition of desensitization, whereas addition of IFN-alpha or IFN-beta is not able to inhibit the LPS-induced desensitization. The inhibition of desensitization by IFN-gamma was dose dependent and time dependent. Preculture of Mono-Mac-6 cells with LPS leads to a strong reduction of TNF mRNA. This reduction of specific mRNA is also overcome by addition of IFN-gamma, but not by IFN-alpha and IFN-beta, indicating that pretranslational mechanisms are responsible for the regulation of TNF in desensitization.

Deficient production of tumor necrosis factor by peripheral-blood monocytes in chronic lymphocytic leukemia

The production of tumor necrosis factor (TNF) by lipopolysaccharide (LPS)-triggered peripheral-blood mononuclear cells (PBM) was investigated in 23 patients with untreated B-cell chronic lymphocytic leukemia (B-CLL) and 14 control donors. Cells were stimulated at concentrations that reflect cell density in peripheral blood. Under these conditions, PBM from 11/23 of the CLL patients produced at least 10-fold less TNF as compared with controls. Monocyte numbers were decreased in percentage, while absolute numbers (normal range 233 +/- 120 X 10(3)/mm3) were decreased only in 2, normal in 17 and increased in 4 patients indicating that the deficiency is not a result of monocytopenia in most patients. Cell separation experiments indicate that after removal of leukemic B cells, percentages of monocytes return to control range and TNF production is improved (7/7). In mixing experiments, we found a suppression of TNF production in control mononuclear cells by CLL cell samples (75 X 10(6) cells/ml) in 5/19 cases, while control cells from thymus exhibited no or little suppression in these conditions. In 2-chamber experiments, leukemic samples suppress TNF production by normal monocytes across a 0.45 micron membrane indicating that a soluble factor is responsible for suppression. The factor exhibits higher stability in serum-free conditions and its molecular weight is below 20 kDa. Prostaglandins are not involved, since indomethacin did not abrogate suppression.

Staphylococcal phosphoenolpyruvate-dependent phosphotransferase system: purification and characterization of the mannitol-specific enzyme IIImtl of Staphylococcus aureus and Staphylococcus carnosus and homology with the enzyme IImtl of Escherichia coli

Enzyme IIImtl is part of the mannitol phosphotransferase system of Staphylococcus aureus and Staphylococcus carnosus and is phosphorylated by phosphoenolpyruvate in a reaction sequence requiring enzyme I (phosphoenolpyruvate-protein phosphotransferase) and the histidine-containing protein HPr. In this paper, we report the isolation of IIImtl from both S. aureus and S. carnosus and the characterization of the active center. After phosphorylation of IIImtl with [32P]PEP, enzyme I, and HPr, the phosphorylated protein was cleaved with endoproteinase Glu(C). The amino acid sequence of the S. aureus peptide carrying the phosphoryl group was found to be Gln-Val-Val-Ser-Thr-Phe-Met-Gly-Asn-Gly-Leu-Ala-Ile-Pro-His-Gly-Thr-Asp- Asp. The corresponding peptide from S. carnosus shows an equal sequence except that the first residue is Ala instead of Gln. These peptides both contain a single histidyl residue which we assume to carry the phosphoryl group. All proteins of the PTS so far investigated indeed carry the phosphoryl group attached to a histidyl residue. According to sodium dodecyl sulfate gels, the molecular weight of the IIImtl proteins was found to be 15,000. We have also determined the N-terminal sequence of both proteins. Comparison of the IIImtl peptide sequences and the C-terminal part of the enzyme IImtl of Escherichia coli reveals considerable sequence homology, which supports the suggestion that IImtl of E. coli is a fusion protein of a soluble III protein with a membrane-bound enzyme II. In particular, the homology of the active-center peptide of IIImtl of S. aureus and S. carnosus with the enzyme IImtl of E. coli allows one to predict the N-3 histidine phosphorylation site within the E. coli enzyme.

Isolation of Aeromonas spp. from an unchlorinated domestic water supply

The recovery of Aeromonas spp. from the unchlorinated water supply for a Western Australian city of 21,000 people was monitored at several sampling points during a period of 1 year. Membrane filtration techniques were used to count colonies of Aeromonas spp., coliforms, and Escherichia coli in water sampled before entry to service reservoirs, during storage in service reservoirs, and in distribution systems. Aeromonas spp. were identified by subculture on blood agar with ampicillin, oxidase tests, and the use of Kaper medium and then were tested for production of enterotoxins and hemolysins. During the same period, two-thirds of all fecal specimens sent for microbiological examination were cultured on ampicillin-blood agar for Aeromonas spp. Recovery of Aeromonas spp. from water supplies at distribution points correlated with fecal isolations and continued during autumn and winter. Coliforms and E. coli were found most commonly in late summer to autumn. This pattern differs from the summer peak of Aeromonas isolations both from water and from patients with Aeromonas spp.-associated gastroenteritis in Perth, Western Australia, a city with a chlorinated domestic water supply. Of the Aeromonas strains from water, 61% were enterotoxigenic, and 64% produced hemolysins.

[Diagnostic value of the determination of serum amylase and serum lipase in suspected acute onset of acute or chronic pancreatitis]

In a prospective study the value of serum amylase and serum lipase determination has been analyzed in 19 patients with an acute episode of acute or chronic pancreatitis and in 19 patients with acute abdomen not due to pancreatitis. The concentration of urinary amylase and the urinary output of amylase in the spot urine as well as after a two-hour collection period have also been examined. The normal values were determined in 21 healthy volunteers and the reproducibility of the various parameters was analyzed after 1 hour and 25 hours in these volunteers. For diagnosis of an acute episode of chronic pancreatitis serum amylase was found to have good sensitivity, but a specificity inferior to that of serum lipase. By contrast, the specificity of serum lipase is excellent. Unlike determination of serum enzymes, measurement of urinary enzymes in all variations does not offer any further advantage. Except for the combination of serum amylase and serum lipase, none of the other tested combinations provides further diagnostic information. The examination of spot urine samples is not inferior to the 2-hour urine specimen. For the time being the combination of serum amylase and serum lipase determination is again recommended for diagnostic routine in patients with an acute episode of pancreatitis.

[Prognosis of chronic systemic-type juvenile arthritis (Still's disease). Numerical analysis of 82 cases]

This study deals with 82 cases of systemic-type chronic juvenile arthritis, 27 of which were followed up over a period of more than 7 years, the development of inflammation of the disease, the extnet of destructive bone lesions and the final functional prognosis. Their conclusion is that, contrary to the traditional notion, this condition often continues to develop beyond adolescence and it often brings about deep-set deterioration of the bones (especially at the wrist and the hip), which has a heavy bearing on the functional prognosis.

Effect of xenon arc photocoagulation on corneal endothelium

Xenon arc photocoagulation of the fundus of pigmented rabbits resulted in no corneal endothelial cell damage when the experiment was designed to minimize corneal temperature rise by frequent topical instillations of ophthalmic irrigating solution.