Molecular characterization of immunoreactivities of peptides derived from chromogranin A (GE-25) and from secretogranin II (secretoneurin) in human and bovine cerebrospinal fluid

Chromogranin A and secretogranin II are members of the so-called chromogranins, the acidic proteins stored in neuroendocrine large dense-core vesicles. We characterized chromogranin A and secretogranin II immunoreactivities in cerebrospinal fluid by radioimmunoassays using synthetic peptides derived from these components (GE-25 for chromogranin A and secretoneurin for secretogranin II). In lumbar cerebrospinal fluid, high levels (more than 1000 fmol/ml) of these two components were found, whereas in ventricular cerebrospinal fluid the secretoneurin levels were relatively low. The cerebrospinal fluid/serum ratio for secretoneurin was close to 170. High-performance liquid chromatography revealed that in both cerebrospinal fluid and extracts from human brain secretoneurin was the predominant immunoreactive component. In cerebrospinal fluid chromogranin A immunoreactivity was present as intermediate-sized peptides with little intact chromogranin A and free GE-25 peptide. In human brain samples smaller peptides including GE-25 were more predominant. Analogous findings for secretoneurin and chromogranin A were obtained for bovine brain samples. We can conclude that chromogranins are present in cerebrospinal fluid in concentrations much higher than those of classical neuropeptides also stored in large dense-core vesicles. Therefore, their degree of proteolytic processing can be analysed with small samples of cerebrospinal fluid. A possible disturbance of proteolytic processing in large dense-core vesicles in various pathological conditions can now be discovered.

Mutations in the R-type pyruvate kinase gene and altered enzyme kinetic properties in patients with hemolytic anemia due to pyruvate kinase deficiency

The biochemical properties of erythrocyte pyruvate kinase (PK) together with mutations found in the coding sequence of the R-PK gene in five patients with severe hemolytic anemia due to PK deficiency are described. The enzyme variants were designated PK 'Mosul' (homozygote), PK 'Bukarest', PK 'Hamburg', PK 'Köln', and PK 'Essen' (compound heterozygote). PK 'Mosul' showed normal positive cooperative substrate binding, PK 'Bukarest' exhibited non-cooperative behavior, and PK 'Hamburg' and PK 'Köln' displayed mixed cooperativity, whereas PK 'Essen' was negative cooperative. PK 'Mosul' was found to be homozygous for the mutation 1151 ACG to ATG, resulting in an amino acid substitution 384 Thr to Met. In one allele of PK 'Bukarest' a single nucleotide substitution GAG-TAG was found at nucleotide 721, causing a change of 241 Glu to a chain termination codon (PK 'Bukarest'). Additionally, in the second allele of this patient a point mutation at position 1594 (CGG-TGG) occurs, changing 532 Arg to Trp (PK 'Bukarest'). Direct sequencing showed the heterozygosity of the patient's mother (PK 'Bukarest'/normal) at position 721 and of the patient's father (PK 'Bukarest'/normal) at position 1594. A point mutation at position 1529 (CGA-CAA), causing an amino acid substitution 510 Arg-Gln, was identified in PK 'Hamburg' and PK 'Köln'. The second mutation in these variants was not detected. In PK 'Essen' no mutation in the coding sequence was found at all. Screening for the mutation at position 1529 in further compound heterozygote patients and in normal subjects of Western European origin showed that this exchange is a common mutation responsible for PK deficiency in this population.

3D reconstruction by combining data from sections cut oblique to different unit cell axes

Oblique section reconstruction (OSR) can produce a 3D image from a single micrograph of a section through a 2D or 3D crystal. Resolution, however, is limited in a direction perpendicular to the section plane. When data from sections cut at different orientations are combined, the inherent resolution limitation for single sections can be overcome. In the extreme, combination of sections cut oblique to different principal planes of the unit cell can produce a 3D reconstruction with isotropic resolution. The merging of data from different sections requires determination of section thickness and orientation. A method for section thickness determination is described that is generally applicable event to space groups with little or no symmetry. In addition, an approach has been developed to determine rotational orientation within the hexagonal lattice of insect flight muscle. Finally, an iterative least-squares fitting method is applied to determine a 3D set of deconvoluted structure factors from the merged data.

[Amputation injuries of large extremity segments. Clinical management]

Amputating injuries are often combined with multiple trauma. The management of these serious traumas has to consider survival more than restoration of function and extremity preservation. Out of 51 patients with 60 macroamputation injuries only one case was successful in replantation. The leading rule in the treatment of macroamputation still must be life before limb, as our series of the years 1988 up to 1991 clearly shows.

[Surgical treatment of diaphyseal tibial fractures. Choice of procedure and results of treatment of 187 fractures]

From 1988 to 1990 a total of 187 fractures of the tibia (92 compound, 95 closed fractures) were treated with a primary osteosynthesis. In 102 fractures an external fixation was performed, 85 internal fixations were divided into 58 intramedullary nails and 27 plates. In a follow-up study the fracture healing was analysed, 90% of the patients were examined about 18 months after the accident. The mean healing time was between 12 weeks (internal fixation) and 16 weeks (external fixateur). After primary Fixateur externe 54 were treated by secondary internal fixation, intramedullary nailing was the method of choice. Contamination rate of the tibia, taken by an intraoperative wound swab before nailing was 30%. Infection occurred in 3.2%, non union and refractures in 1.5% and 1%. Over all 80% excellent and good results were found after consolidation. 10% fair and 10% bad results including three amputations after III degrees compound fractures and three death after polytrauma.

Selective inhibition of E-selectin, ICAM-1, and VCAM in endothelial cells

Endothelial cells, as they normally exist in the vasculature as quiescent cells, perform several functions. In an inflammatory response, endothelial cells are activated to up-regulate a number of genes, including E-selectin (ELAM-1), VCAM-1, ICAM-1, interleukin (IL)-1, IL-8 and plasminogen activator inhibitor-1 (PAI-1). Very little is known about factors that regulate the activation process. We describe here that a heat-stable protein, normally present in the alpha-globulin fraction of serum, inhibits induced expression of E-selectin, ICAM-1, and VCAM-1 in vitro and also impedes the accumulation of mRNA for these molecules. Inhibition of E-selectin, the only gene tested in this respect, is at the level of transcription. At the same time, the alpha-globulins do not, under the same conditions, repress mRNA accumulation for IL-1, IL-8, or PAI-1. The effect of the inhibitor does not relate to constraints on function of nuclear-factor kappa B, the induced activity of which is not interfered with at the early time points at which the suppression of these three genes is seen.

[Treatment of acromioclavicular joint dislocation by tension band and ligament suture]

From 1. 1. 1988 until 30. 6. 1990 54 patients with acromio-clavicular luxation and 3 patients suffering from lateral fractures of the clavicula were treated with tension-bend-wiring combined to suturing the acromio- and coracoclavicular ligaments at the BG-Unfallklinik Ludwigshafen. In 8 cases (14%) complications due to the implant occurred. Infection was found in 4 cases (7%). 47 patients (82.5%) could be followed clinically with mean follow-up time of 21.5 month. Clinical criteria like interpretation of the result by the patient, clinical and radiological findings were quantitatively and qualitatively interpreted by a score.

Large dense-core vesicles in rat adrenal after reserpine: levels of mRNAs of soluble and membrane-bound constituents in chromaffin and ganglion cells indicate a biosynthesis of vesicles with higher secretory quanta

Rats were injected with a large dose of reserpine known to stimulate the adrenal medulla. Various times after drug treatment the mRNA levels of several constituents of large dense-core vesicles were determined by northern blot analysis and in situ hybridization. The latter method allowed detection of changes in mRNA levels not only in chromaffin cells, but also in the ganglion cells found in adrenal medulla. Levels of the mRNAs of secretory components of large dense-core vesicles (chromogranins A and B, secretogranin II, VGF, and neuropeptide Y) increased in chromaffin cells by 215-857% after 1-3 days of drug treatment. For partly membrane-bound components (dopamine beta-hydroxylase, prohormone convertase 2, carboxypeptidase H, and peptidylglycine alpha-amidating monooxygenase) the changes ranged from 182 to 315%, whereas for glycoprotein III and for intrinsic membrane proteins (cytochrome b561 and vesicle monoamine transporter 2) no change occurred. In ganglion cells the mRNAs that could be detected for VGF, neuropeptide Y, secretogranin II, carboxypeptidase H, and vesicle monoamine transporter 1 showed an analogous pattern of change, with significant increases for the secretory proteins and no change for the membrane components. From these and previous results we suggest the following concept: Long-lasting stimulation of chromaffin cells or neurons does not induce the biosynthesis of a larger number of vesicles but rather leads to the formation of vesicles containing higher secretory quanta of chromogranins and neuropeptides.

Release of secretoneurin and noradrenaline from hypothalamic slices and its differential inhibition by calcium channel blockers

Secretoneurin is a newly discovered peptide found in high concentrations in brain. We have studied the release of secretoneurin and noradrenaline from superfused hypothalamic slices from rat brain. Both electrical stimulation and potassium induced depolarisation released secretoneurin and noradrenaline from these slices in a calcium-dependent manner. Electrical stimulation caused a preferential release of noradrenaline when compared to the secretion elicited by high potassium. The time course of secretoneurin release was more protracted than that of noradrenaline. The calcium channel blocker omega-conotoxin inhibited only the electrically induced release of noradrenaline, whereas nifedipine inhibited only that of secretoneurin. These results establish that secretoneurin is secreted from neurons. Inhibition of this release by nifedipine is consistent with the concept that secretion from large dense core vesicles occurs at sites different from that of small vesicles and depends on calcium influx via L-type calcium channels.

Human and rat primary C-fibre afferents store and release secretoneurin, a novel neuropeptide

Secretoneurin is a recently discovered neuropeptide derived from secretogranin II (SgII). Since this peptide could be detected in the dorsal horn of the spinal cord we studied whether it is localized in and released from primary afferent neurons. Secretoneurin was investigated with immunocytochemistry and radioimmunoassay in spinal cord, dorsal root ganglia and peripheral organs. SgII mRNA was determined in dorsal root ganglia. Normal rats and rats pre-treated neonatally with capsaicin to destroy selectively polymodal nociceptive (C-) fibres were used. Slices of dorsal spinal cord were perfused in vitro for release experiments. Immunocytochemistry showed a distinct distribution of secretoneurin-immunoreactivity (IR) in the spinal cord and, lower brainstem. A particularly high density of fibres was found in lamina I and outer lamina II of the caudal trigeminal nucleus and of the spinal cord. This distribution was qualitatively identical in rat and human post-mortem tissue. Numerous small diameter and some large dorsal root ganglia neurons were found to contain SgII mRNA. Capsaicin treatment led to a marked depletion of secretoneurin-IR in the substantia gelatinosa, but not in other immunopositive areas of the spinal cord and to a substantial loss of small (< 25 microns) SgII-mRNA-containing dorsal root ganglia neurons. Radioimmunoassay revealed a significant decrease of secretoneurin-IR in the dorsal spinal cord, the trachea, heart and urinary bladder of capsaicin-treated rats. Perfusion of spinal cord slices with capsaicin as well as with 60 mM potassium led to a release of secretoneurin-IR. In conclusion, secretoneurin is a neuropeptide which is stored in and released from capsaicin-sensitive, primary afferent (C-fibre) neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine chromaffin cells: studies on the biosynthesis of phospholipids in chromaffin granules

We have studied the biosynthesis of chromaffin granules by labelling primary cultures of bovine chromaffin cells with either [35S]methionine or various precursors for lipids. After labelling the cells were subjected to subcellular fractionation including density gradient centrifugation. After [35S]methionine significant label (mainly represented by labelled chromogranin A) was found in the soluble proteins of chromaffin granules, whereas the membranes were relatively little labelled. However incorporation into membrane bound dopamine beta-hydroxylase and cytochrome b-561 could be demonstrated. Neither of the used lipid precursors ([3H]glycerol, [3H]choline, [3H]palmitic acid or [3H]arachidonic acid) was incorporated to any significant extent into the soluble components of chromaffin granules. Thus there is no evidence that this secretory compartment contains any lipids or acylated proteins. Incorporation of lipid precursors into the membranes of chromaffin granules was apparently low. After short chases labelled lysolecithin was not present in these organelles. However with prolonged chase times labelled lysolecithin, apparently appeared in chromaffin granules irrespective of whether the cells were stimulated or not. We can conclude that the reusable membranes of chromaffin granules have a very low lipid turnover. Lysolecithin is not transferred into these organelles during biosynthesis but is formed in them during their long life span. This formation of lysolecithin is independent of stimulation of these cells and therefore unlikely to be involved in exocytosis.

Mössbauer and magnetic susceptibility studies on iron(II) metallothionein from rabbit liver. Evidence for the existence of an unusual type of [M3(CysS)9]3- cluster

The magnetic properties of the Fe(II)-binding sites in Fe(II)7-metallothionein (MT) have been studied using Mössbauer spectroscopy and magnetic-susceptibility measurements. In agreement our previous results, simulation of the Mössbauer spectra showed the presence of paramagnetic and diamagnetic subspectra in the ratio 3:4. By comparison with Mössbauer spectra of the inorganic adamantane-like (Et4N)2[Fe4(SEt)10] model compound, the diamagnetic component in Fe(II)7-MT has been assigned to a four-metal cluster in which there is antiferromagnetic coupling between the high-spin Fe(II) ions. It is suggested that the organization of this cluster is similar to that determined in the three-dimensional structure of the protein, containing diamagnetic Zn(II) and/or Cd(II) ions. From magnetic-susceptibility studies, an average magnetic moment of approximately 8.5 microB was obtained for the three remaining bound Fe(II) ions, responsible for the paramagnetic component observed in the Mössbauer studies. This value is slightly lower than that for three completely uncoupled Fe(II) ions, suggesting the existence of a three-metal cluster within which there is weak exchange coupling between adjacent Fe(II) ions. The spin-Hamiltonian formalism including, besides zero-field and Zeeman interaction, also exchange interaction among the three Fe(II) ions in the three-metal cluster, H = -J12 (S1.S2)-J23 (S2.S3)-J13 (S1.S3), was applied to simulate both magnetic-Mössbauer and magnetic-susceptibility data. Reasonable fits were achieved only with values magnitude of J12 = magnitude of J23 = magnitude of J13 = magnitude of J < 1 cm-1. Such a situation could not be reconciled with the chair-like geometry of the [M3(CysS)9]3- cluster determined with paramagnetic metal ions, where significantly stronger coupling would be anticipated (magnitude of J = 50-70 cm-1). However, modest exchange-coupling properties have been reported for a number of crystallographically characterized trinuclear [Fe3(SR)3X6]3- clusters (X = Cl, Br; R = Phe, p-tolyl, 2,6-Me2C6H3) distinguished by the preferential formation of a planar Fe3(mu 2-SR)3 ring [Whitener, M. A., Bashkin, J. A., Hagen, K. S., Girerd, J.-J., Gamp, E. Edelstein, N. & Holm, R. H. (1986) J. Amer. Chem. Soc. 108, 5607-5620]. It is therefore more likely that a pseudo-planar geometry rather than a chair-like geometry is present in the Fe3 cluster of Fe(II)7-MT. This would represent the first example of structural differences on binding divalent metal ions to this protein.

Distribution of secretoneurin immunoreactivity in the spinal cord and lower brainstem in comparison with that of substance P and calcitonin gene-related peptide

Secretoneurin is a peptide of 33 amino acids generated in brain by proteolytic processing of secretogranin II. The distribution of this newly characterized peptide was investigated by means of immunocytochemistry and in situ hybridization in the spinal cord and lower brainstem of the rat. The staining pattern of secretoneurin immunoreactivity (IR) was compared to that of substance P (SP) and calcitonin gene-related peptide (CGRP) in adjacent sections. A high density of secretoneurin-IR fibers and terminals was found in lamina I and outer lamina II of the caudal trigeminal nucleus and of the spinal cord at all levels, around the central canal, and in the sympathetic and parasympathetic areas of the lateral cell columns. The ventral horn displayed a low to moderate density of secretoneurin-IR. The highest number of secretogranin II mRNA-containing cells was found in lamina II of the dorsal horn and in neurons of the dorsal root ganglia. In the white matter, secretoneurin-IR was most prominent in the dorsolateral part of the lateral funiculus and in the tract of Lissauer. The distributions of secretoneurin-IR and SP-IR were strikingly similar. CGRP-IR and secretoneurin-IR overlapped in the outer laminae of the dorsal horn, in the lateral cell column, and probably in some motoneurons. This study establishes that, like SP and CGRP, secretoneurin is a peptide highly concentrated in the terminal field of primary afferents and in sympathetic and parasympathetic areas. Thus secretoneurin might be involved in the modulation of afferent transmission.

Bovine posterior pituitary: presence of p65 (synaptotagmin), PC1, PC2 and secretoneurin in large dense core vesicles

The subcellular distribution of p65 (synaptotagmin), of the endoproteases PC1 and PC2 and of secretoneurin was studied in bovine posterior pituitary by differential and density gradient centrifugation. All these peptides were found to be present in the neurosecretory granules (large dense core vesicles). p65 can therefore participate not only in exocytosis from small synaptic vesicles but also from large dense core vesicles. Secretoneurin is a peptide derived from secretogranin II. Processing of the propeptide apparently occurs during axonal transport of the large dense core vesicles and is complete in the posterior pituitary. Thus, stimulation of the hypothalamic magnocellular neurons can lead to the release of this newly characterized, functional neuropeptide.

Experience with the pinless fixator in the treatment of fractures of the lower leg

This is a report of the experience we have gathered in the application of the pinless fixator in cases of tibial fracture with soft tissue damage. In the Berufsgenossenschaftlichen Unfallklinik Ludwigshafen (Clinic for Trauma Surgery) 12 diaphyseal fractures of the tibia were stabilized with the pinless fixator in 1991. In all cases, conversion to an intramedullary nail was intended from the very beginning and was performed in 11 cases. In one case, a conventional external fixator had to be selected instead. The injuries included first and second degree open and closed fractures, mostly from group A of the AO classification. At conversion four bacteriological smear tests from the medullary cavity proved positive. In four cases, transitory peroneal deficiencies were diagnosed. When investigating their cause, it seemed that the present geometry of the pinless arms might be responsible for pressure damage to the soft tissues. Possibly this difficulty could be solved by altering the configuration of these arms. The pinless external fixator has definitely proved its usefulness when later conversion to an intramedullary nail is intended since the final fixation can be performed with the pinless device still in place.

Ontogenic development and distribution of mRNAs of chromogranin A and B, secretogranin II, p65 and synaptin/synaptophysin in rat brain

We have studied by in situ hybridization the mRNA levels of several constituents of transmitter storing vesicles during ontogenic development of rat brain. The following vesicle components were investigated: chromogranin A and B and secretogranin II, representing secretory peptides of large dense core vesicles, and the membrane proteins p65 and synaptin/synaptophysin which are found in both large and small synaptic vesicles but are concentrated in the latter ones. Several ontogenic patterns were observed: concomitant increases of most or all mRNAs in certain brain regions, e.g. in the thalamic nuclei at gestational day 18 or in the cortex at postnatal day 6. For some areas selective increases for the various chromogranin mRNAs occurred, thus throughout development the substantia nigra compacta contained only the chromogranin B mRNA, whereas the lateral and medial geniculate nuclei and the medial tuberal nucleus expressed only secretogranin II mRNA. In the paraventricular hypothalamic nucleus, secretogranin II mRNA declined at P1 and then increased again. In the intermediate cortex there was a rather selective appearance of a high level of chromogranin A mRNA already at gestational day 16. In general the mRNAs for the membrane components become detectable by in situ hybridization together with the chromogranin mRNA, however, in the claustrum a high level of the p65 mRNA is present already at gestational day 16 whereas the chromogranin mRNA only appears at day 20. In some nuclei there was also a differential expression of the membrane components with e.g. the synaptophysin mRNA being present without any concomitant appearance of p65. These results establish that the ontogenic development of the investigated components in many brain areas simply indicate the starting point of biosynthesis of both types of vesicles finally leading to functional synapses. In those cases where a selective dissociation in the biosynthesis of these components occurs, a functional relevance of one component for a certain stage of development might be postulated. Since these data define the time of onset of vesicle biosynthesis in the various brain regions, future studies on single components of these vesicles can be interpreted in the context of the present findings.

Attraction of human monocytes by the neuropeptide secretoneurin

Secretoneurin is a newly discovered 33-amino-acid peptide derived from secretogranin II (chromogranin C) that is found in sensory afferent C-fibers. We show here that secretoneurin triggers the selective migration of human monocytes in vitro and in vivo. Combinations of secretoneurin with the sensory neuropeptides, substance P or somatostatin, synergistically stimulate such migration. The attraction of monocytes represents the first established function of secretoneurin as a sensory neuropeptide.