Monoclonal antibody immunocytochemistry: novel method extending usefulness of monoclonal antibodies for antigen visualization

We describe a novel procedure combining the multiple-site reactivity of polyclonal antibodies with the defined single epitope-specificity of monoclonal antibodies. The method is based on previous findings that IgG molecules often only react with tissue-bound antigens with one of their two antigen-combining sites; thus, the remaining site is free to bind subsequently added antigen. In the procedure devised, such (undenatured) antigen is subsequently detected by a specific monoclonal antibody and the reaction is finally revealed by immunogold-silver staining. Antibody subpopulations to contaminating antigens may well be present in the polyclonal antiserum and may well bind first to tissue and then to the corresponding contaminants in the crude antigen preparation applied as second layer. Such contaminants will, however, not react with the monoclonal antibody and will therefore not be immunocytochemically detected. The method has been evaluated with one antigen which cannot be detected by monoclonal antibodies in paraffin sections (glial fibrillar acidic protein) and with another antigen (human chorionic gonadotropin) which can only be detected by the monoclonal antibody when occurring in high concentrations. In both cases the procedure resulted in strong specific staining of the antigens with no background.

Ecto-protein kinase activity on the external surface of neural cells

ATP is secreted in association with neurotransmitters at certain synapses and neuromuscular junctions. Extracellular ATP is known to exert potent effects on the activity of cells in the nervous system, where it can act as a neurotransmitter or as a modulator regulating the activity of other neurohormones. We have suggested that such modulation may involve the activity of extracellular protein phosphorylation systems. It is well known that intracellular protein kinases are important in the regulation of various neuronal functions, but protein kinases which use extracellular ATP to phosphorylate proteins localized at the external surface of the plasma membrane (ecto-protein kinases) have not been demonstrated in neuronal cells. Here we present direct evidence for the existence of an ecto-protein kinase and demonstrate endogenous substrates for its activity at the surface of intact neural cells. The phosphorylation of one of these surface proteins is selectively stimulated during cell depolarization. In addition, neuronal cell adhesion molecules (N-CAMs) appear to be among the substrates of ecto-protein kinase activity. These results suggest a role for surface protein phosphorylation in regulating specific functions of developing and mature neurones.

Aminosäurenzufuhr beim akuten, noch kompensierten Nierenversagen in der posttraumatischen Phase

Zur Auswertung kamen 3 Patientengruppen, die im kompensierten akuten Nierenversagen nach vorangegangener Operation isokalorisch (1700 kcal) und annähernd isonitrogen (33–36 g Aminosäuren), jedoch mit verschiedenen Aminosäurengemischen, ernährt wurden. Neben der einheitlichen täglichen Energiezufuhr von 750 ml Invert-zucker 40% und 250 ml Lipofundin®S 20% betrug die tägliche Aminosäureninfusion in Gruppe I (n = 13) ausschlieβlich 500 ml EAS pfrimmer (34,5 g), in Gruppe II (n = 10) 250 ml EAS pfrimmer und 250 ml Intrafusin® 7,5 % E (36 g) und in Gruppe III (n = 16) 250 ml EAS pfrimmer und 350 ml Aminofusin® Hepar (33,1 g). Bei der Auswertung der Aminogramme konnten bereits zu Beginn der Studie in alien 3 Patientengruppen unter den unteren Referenzbereich erniedrigte Ausgangswerte von Glyzin, Serin, Arginin und Histidin im Serum gemessen werden. Im Verlauf der 4tägigen Infusionstherapie zeigten sich bezüglich einer Verbesserung der Serumwerte die Patienten der Gruppe II und III denen der Gruppe I überlegen. Dagegen waren die Serumspiegel von Phenylalanin, Methionin und 3-Methyl-Histidin bereits zu Beginn auf das 2–3fache des Referenzbereiches erhöht. Bezüglich einer Senkung der hohen Einzelwerte im Serum war die Patientengruppe II der Gruppe I und III überlegen. Im klinischen Verlauf waren keine signifikanten Unterschiede zu erkennen.

Developmental study of detergent solubility and polypeptide composition of the neural cell adhesion molecule

The neural cell adhesion molecule (N-CAM), a glycoprotein synthesized by neurons, glial cells and muscle cells, is involved in cell-cell adhesion. In this report we describe developmental changes in the amount of N-CAM polypeptides in rat forebrain and in detergent solubility of N-CAM. The amount of N-CAM changed during development with a peak in early postnatal life. N-CAM was composed of the following polypeptides: HMr (molecular weight between 250,000 and 350,000 daltons), A (200,000 daltons), B (135,000 daltons) and C (115,000 daltons). In embryonic life N-CAM consisted of 10% HMr, 26% A, 53% B and 11% C. During development only the relative amount of polypeptide C increased significantly, from 11% at embryonic day 17 to 22% at postnatal day 4. Postnatally the polypeptide composition of N-CAM did not change. No Triton X-100 insoluble N-CAM was observed in early development, but at postnatal day 40 14% of N-CAM was Triton X-100 insoluble. This fraction was shown to consist of polypeptide C.

Biosynthesis of the neural cell adhesion molecule: characterization of polypeptide C

The biosynthesis of the neural cell adhesion molecule (N-CAM) was studied in primary cultures of rat cerebral glial cells, cerebellar granule neurons, and skeletal muscle cells. The three cell types produced different N-CAM polypeptide patterns. Glial cells synthesized a 135,000 Mr polypeptide B and a 115,000 Mr polypeptide C, whereas neurons expressed a 200,000 Mr polypeptide A as well as polypeptide B. Skeletal muscle cells produced polypeptide B. The polypeptides synthesized by the three cell types were immunochemically identical. The membrane association of polypeptide C was investigated with methods that distinguish peripheral and integral membrane proteins. Polypeptide C was found to be a peripheral membrane protein, whereas polypeptides A and B were integral membrane proteins with cytoplasmic domains of approximately 50,000 and approximately 25,000 Mr, respectively. The affinity of the membrane binding of polypeptide C increased during postnatal development. The posttranslational modifications of polypeptide C were investigated in glial cell cultures, and it was found to be N-linked glycosylated and sulfated.

Demonstration of immunochemical identity between the nerve growth factor-inducible large external (NILE) glycoprotein and the cell adhesion molecule L1

The nerve growth factor-inducible large external (NILE) glycoprotein and the neural cell adhesion molecule L1 were shown to be immunochemically identical. Immunoprecipitation with L1 and NILE antibodies of [3H]fucose-labeled material from culture supernatants and detergent extracts of NGF-treated rat PC12 pheochromocytoma cells yielded comigrating bands by SDS-PAGE. NILE antibodies reacted with immunopurified L1 antigen, but not with N-CAM and other L2 epitope-bearing glycoproteins from adult mouse brain. Finally, by sequential immunoprecipitation from detergent extracts of [35S]methionine-labeled early post-natal cerebellar cell cultures or [3H]fucose-labeled NGF-treated PC12 cells, all immunoreactivity for NILE antibody could be removed by pre-clearing with L1 antibody and vice versa.

Immunocytochemical demonstration of calmodulin in cells secreting by exocytosis

Calmodulin is a regulator of several calcium-dependent cellular processes. It has been suggested that it plays a role in the mechanism of secretion. Employing an indirect immunoperoxidase technique at the light microscope level, this study demonstrates the presence of calmodulin in several exocytotic cells (mast cells, thyroid follicular cells, neurohypophyseal neurosecretory terminals, pancreatic beta-cells and pancreatic acinus cells) in rat and man. The positive staining reaction for calmodulin was granular and at least in the case of rat mast cells it appeared to be associated with the granule membrane.

High cerebrospinal fluid concentration of glial fibrillary acidic protein (GFAP) in patients with normal pressure hydrocephalus

The concentration of glial fibrillary acidic protein (GFAP) in lumbar cerebrospinal fluid (CSF) was measured in 12 patients with normal pressure hydrocephalus (NPH) 11 patients with primary degenerative dementia (PDD), 8 patients with various other neurological diseases, and 18 patients without signs of organic nervous disease (controls). Mean CSF GFAP concentration was significantly higher in NPH patients: 96 +/- 23 ng/ml (SEM) when compared with PDD patients: 8.2 +/- 1.9 ng/ml (P less than 0.01), or with controls: 4.3 +/- 0.7 ng/ml (P less than 0.01). Only 2 NPH patients had a GFAP concentration within the range of the control group (2-14 ng GFAP/ml CSF). No significant differences were found between the PDD patients and the control group, or between the group of patients with other neurological diseases and the control group. In addition, a rostro-caudal gradient of GFAP in CSF could be demonstrated. In 6 NPH and 2 PDD patients both ventricular and lumbar CSF samples were investigated. In all cases the ventricular GFAP concentration was higher than the lumbar concentration. The difference was statistically significant (P less than 0.01). Our results suggest that determination of CSF GFAP concentration might be of diagnostic value in discrimination between NPH patients and patients with enlarged ventricles associated with degenerative brain disease.

Differentiation markers (S-100, GFAP, NSE and D2) in fetal rat brain cells during malignant transformation in cell culture

Malignant cell lines obtained by ethylnitrosourea (EtNU)-induced transformation of fetal rat brain cells in culture express protein markers of different types of neural cells. These are the nervous system-characteristic S-100 protein; glial fibrillary acidic protein (GFAP); neuron-specific-enolase (NSE), and the D2-cell adhesion molecule. S-100 protein was absent in fetal brain cells in culture, but gradually appeared in the later stages of malignant transformation and further increased at onset of rapid growth of atypical cells (stage IV). GFAP and D2 were weakly expressed in primary fetal brain cells and did not change throughout malignant transformation. NSE was present in both normal and carcinogen-treated fetal brain cells, and increased at later stages of malignant transformation. From stage III (40-100 days) some cultures were strongly positive and some negative, and the same was seen in the resulting tumorigenic cells about 100 days later. In conclusion the stepwise process of malignant transformation of brain cells in culture ended with a stable phenotype of cells capable of expressing varying types of differentiation markers. The presence of these markers in rat brain cells undergoing malignant transformation may indicate that EtNU given at 18th days of gestation is acting on multipotent neuroectodermal cells.

[Efficacy of early amino acid substitution in gastrectomized patients]

Postaggression metabolism is characterized by decisive, hormone dependent metabolic changes. All reactions are directed with top priority toward ensuring the energy supply. To this end glycogenolysis, gluconeogenesis and lipolysis are increased. Since this reaction of the organism can barely be influenced and it appears to be teleologically purposeful, many authors have repeatedly attempted to achieve a utilization of nutrients as high and economic as possible using an infusion regimen adapted to these conditions. We studied the efficiency of one such adapted nutritional regimen during the first four postoperative days in 10 patients who had undergone gastrectomy. The patients were given 1 g/kg B.W. daily of an amino acid solution adapted to postaggression metabolism, plus 4 g/kg B.W. carbohydrates. We found that clinically relevant parameters such as glucose in serum, triglycerides in serum and pre-albumin could be kept in the reference range. Amino acid homeostasis remained stable under the infusion of the stress adapted amino acid solution. A rise in urea production was not observed. We conclude that good conditions for an economic utilization of the amino acids were created by the infusion regimen selected by us. These results probably can still be optimized by targetted preoperative nutrition with the goal of improving the protein status of such patients already during the preoperative phase.

Quantification of glial fibrillary acidic protein (GFAP) in human body fluids by means of ELISA employing a monoclonal antibody

Soluble glial fibrillary acidic protein (GFAP) was quantified in human cerebrospinal fluid (CSF) and amniotic fluid. A normal value in lumbar CSF of 4.3 +/- 0.7 ng GFAP/ml (mean +/- SEM) was obtained from 18 non-neurological patients. Increased GFAP concentrations in CSF were found in patients with intracranial tumours or with normal pressure hydrocephalus, while normal values were found in multiple sclerosis patients and in patients with degenerative dementia. In addition, a concentration gradient between ventricular and lumbar CSF was demonstrated, the GFAP content being significantly higher in ventricular than in lumbar samples. Amniotic fluids from normal pregnancies contained 13 +/- 5.5 ng GFAP/ml (N = 117). Increased GFAP concentrations were observed in amniotic fluid from some but not all pregnancies with fetal anencephaly or encephalocele, but not from pregnancies with fetal spina bifida or any of the other fetal malformations investigated. The quantification method was an enzyme-linked immunosorbent assay employing a monoclonal antibody specific for GFAP.

Cell-free synthesis of the D2-cell adhesion molecule: evidence for three primary translation products

The D2-cell adhesion molecule (D2-CAM) is a membrane glycoprotein that is involved in cell-cell adhesion in the nervous system. To study the biosynthesis of D2-CAM we have translated free and membrane-bound polysomes from rat brain in vitro in the rabbit reticulocyte lysate system. D2-CAM was exclusively synthesized on membrane-bound polysomes. The primary translation products of D2-CAM were three polypeptides of apparent molecular weights 187,000, 134,000, and 112,000. No interconversion between these polypeptides was detected. In contrast to previous suggestions, we conclude that all three D2-CAM polypeptides are primary translation products. When translating polysomes from embryonic and postnatal rat brain, we found that the relative amounts of the three polypeptides synthesized varied with age. Their molecular weights, however, were not age-dependent.

Enzyme-linked immunosorbent assay for the human glial fibrillary acidic protein using a mouse monoclonal antibody

Two enzyme-linked immunosorbent assays (ELISAs) have been developed for the quantification of soluble human glial fibrillary acidic protein (GFAP). The specificity of the assays for GFAP is ensured by the use of a monoclonal antibody directed against a GFAP-specific antigenic determinant. One ELISA is a four-layer system working in the concentration range 5-600 ng GFAP/ml. The other ELISA is a five-layer system and includes a biotin/avidin binding reaction. The latter assay has a working range of 0.5-60 ng GFAP/ml. The assays may be used for quantification of GFAP in CSFs, amniotic fluids, and extracts or homogenates of normal and pathological brain material. GFAP in serum could not be quantified because of unidentified interference. CSFs from 18 nonneurological subjects were found to contain 2-14 ng GFAP/ml (mean 4.1 ng/ml), whereas amniotic fluids from 50 normal pregnant women contained up to 24 ng GFAP/ml (mean 12.4 ng/ml). GFAP concentrations in CSFs from 32 multiple sclerosis patients were found not to be elevated compared to the control group.

Purification of gamma-enolase messenger ribonucleic acid from rat brain by an immunoadsorption method

Messenger ribonucleic acid (mRNA) coding for the brain-specific protein gamma-enolase was isolated by an immunopurification procedure. Rat brain polysomes including nascent polypeptide chains were reacted with specific gamma-enolase antibody. The polysome-antibody complexes were subsequently adsorbed to protein A-Sepharose. After extensive washing, RNA was eluted and applied to an oligo(dT)-cellulose column. Purified mRNA was translated in vitro in a mRNA-dependent rabbit reticulocyte lysate system. The synthesized product was identical to gamma-enolase synthesized by free polysomes from rat brain. Immunoisolated gamma-enolase mRNA was enriched 380-fold compared to total mRNA extracted from free polysomes. This result indicates that low-abundance mRNAs may conveniently be isolated from brain tissue by immunoadsorption of polysomes.

A developmental study of the biosynthesis of the neural cell adhesion molecule

The neural cell adhesion molecule (N-CAM) is a glycoprotein found in neurons, glial cells and muscle cells. In this report we describe developmental changes in biosynthesis of N-CAM polypeptides in rat forebrain explant cultures. N-CAM was synthesized as the following polypeptides: HMr (Mr between 250,000 and 350,000), A (200,000 Mr), B (135,000 Mr) and C (115,000 Mr). The biosynthetic pattern of N-CAM polypeptides changed during development: the biosynthesis of HMr and C increased relative to A and B. N-CAM biosynthesis decreased 100-fold from embryonic day 17 to postnatal day 25; N-CAM turnover decreased 350-fold during the same period. N-CAM polysialylation and sulfatation decreased markedly with age, whereas phosphorylation seemed to be constant during development. Only polypeptides A and B were phosphorylated, whereas A, B and C were sulfated. A was more sulfated and phosphorylated than B. It is concluded that the above described modulations of N-CAM may be of importance in the developmental regulation of cell-cell adhesion.

Biosynthesis of the D2-cell adhesion molecule: post-translational modifications, intracellular transport, and developmental changes

Posttranslational modifications and intracellular transport of the D2-cell adhesion molecule (D2-CAM) were examined in cultured fetal rat neuronal cells. Developmental changes in biosynthesis were studied in rat forebrain explant cultures. Two D2-CAM polypeptides with Mr of 187,000-210,000 (A) and 131,000-158,000 (B) were synthesized using radiolabeled precursors in cultured neurons. A and B were found to contain only N-linked complex oligosaccharides, and both polypeptides appeared to be polysialated as determined by [14C]mannosamine incorporation and precipitation with anti-polysialic acid antibody. The two polypeptides were sulfated in the trans-Golgi compartment and phosphorylated at the plasma membrane. D2-CAM underwent rapid intracellular transport, appearing at the cell surface within 35 min of synthesis. A and B were shown to be integral membrane proteins as seen by radioiodination by photoactivation employing a hydrophobic labeling reagent. In rat forebrain explant cultures, D2-CAM was synthesized as four polypeptides: A (195,000 Mr), B (137,000 Mr), C (115,000 Mr), and a group of polypeptides in the high molecular weight region (HMr) between 250,000 and 350,000. Peptide maps of the four polypeptides yielded similar patterns. Biosynthesis of C and HMr increased with age, relative to A and B. A and B were sulfated in embryonic brain, however, sulfation was not noticeable at postnatal ages. Phosphorylation, on the other hand, of A and B was observed at all ages examined. We suggest that D2-CAM function may be modified during development by changes in the relative synthesis of the different polypeptides, as well as by changes in their glycosylation and sulfation.

Glial fibrillary acidic protein in amniotic fluids from pregnancies with fetal neural tube defects

The glial fibrillary acidic protein (GFAP) is the subunit protein of intermediate filaments in astrocytes and closely related cell types. By means of an enzyme immunoassay we have determined the concentration of GFAP in amniotic fluids from normal pregnancies and from pregnancies complicated by various fetal malformations. The group of 20 cases of fetal anencephaly had a significantly higher mean amniotic fluid GFAP concentration (115 micrograms/l +/- 133.6 (S.D.), range 6-378 micrograms/l) than the control group of 117 normal pregnancies (13 micrograms/l +/- 5.5 (S.D.), range 0-31 micrograms/l), (P less than 0.001). Two cases of fetal encephalocele likewise had very high amniotic fluid GFAP concentrations. None of the other cases of fetal malformations investigated, including 12 cases of spina bifida, had increased amniotic fluid GFAP concentrations. We conclude that determination of the amniotic fluid GFAP concentration may give additional information in the prenatal diagnosis of fetal nervous system malformations.

Long-lived metastable states and hysteresis in the binding of acetylcholine to Torpedo california acetylcholine receptor

Studies of the binding of [3H]acetylcholine to receptor-rich membranes of Torpedo californica electric organ under conditions that normally lead to a state of equilibrium did not give rise to equilibrium binding curves. Instead, the acetylcholine receptor was found to develop very long lived metastable states resulting in hysteresis in binding. Under conditions where the concentration of free [3H]acetylcholine is both less than 0.1 microM and smaller or comparable to the total receptor concentration, the degree of binding of acetylcholine depends on the rate, i.e., the mode, of increasing the acetylcholine concentration (rapid mixing vs. dialysis). The equilibrium positive cooperativity in high-affinity acetylcholine binding previously inferred from the data is deceiving; the curvature in Scatchard representations is a consequence of long-lived nonequilibrium distributions between high-affinity and lower affinity receptor conformers. By manipulation of the experimental conditions, true equilibrium binding, resulting in a linear Scatchard binding curve, was obtained and yielded the apparent equilibrium constant, K = 5 +/- 1 nM at 4 degrees C. The stoichiometry of the high-affinity site associated with this K value was found to be one acetylcholine per receptor monomer (Mr 250 000) when carefully standardized [3H]acetylcholine analyzed for both radiopurity and acetylcholine concentration was used. While our fresh membrane fragments prepared in the presence of 4 mM Ca2+ revealed up to twice as many 125I-alpha-bungarotoxin sites in 0.1% nonionic detergent relative to those assayed in the absence of detergent, nonionic detergent treatment of membrane fragments did not result in any change in total available acetylcholine binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

An unusual kind of muscular and skeletal involvement in a heroin addict. A case report

After a brief review of the infectious complications that frequently occur in heroin users, the authors report a case of chronic osteomyelitis affecting the ulnar diaphysis bilaterally. Musculo-cutaneous dystrophic lesions were also present and resulted in forced flexion of the distal phalanges of fingers 2-5. The most likely pathogenetic development discussed.

Biosynthesis of the D2 cell adhesion molecule: pulse-chase studies in cultured fetal rat neuronal cells

D2 is a membrane glycoprotein that is believed to function as a cell adhesion molecule (CAM) in neural cells. We have examined its biosynthesis in cultured fetal rat brain neurones. We found D2-CAM to be synthesized initially as two polypeptides: Mr 186,000 (A) and Mr 136,000 (B). With increasing chase times the Mr of both molecules increased to 187,000-201,000 (A) and 137,000-158,000 (B). These were similar to the sizes of D2-CAM labeled with [14C]glucosamine, [3H]fucose and [14C]mannosamine, indicating that the higher Mr species are glycoproteins. In the presence of tunicamycin, which specifically blocks the synthesis of high mannose cores, Mr were reduced to 175,000 (A) and 124,000 (B). Newly synthesized A and B are susceptible to degradation by endo-beta-N-acetyl-glucosaminidase H, which specifically degrades high mannose cores, but they are resistant to such degradation after 150 min of posttranslational processing. Hence, we deduce that A and B are initially synthesized with four to five high mannose cores which are later converted into N-linked complex oligosaccharides attached to asparagine residues. However, no shift of [35S]methionine radioactivity between A and B was detected with different pulse or chase times, showing that these molecules are not interconverted. Thus, our data indicate that the neuronal D2-CAM glycoproteins are derived from two mRNAs.

The neural cell adhesion molecule L1 is distinct from the N-CAM related group of surface antigens BSP-2 and D2

The neural cell adhesion molecule L1 and the group of N-CAM related molecules, BSP-2 and D2 antigen, are immunochemically distinct molecular species. The two groups of surface molecules are also functionally distinct entities, since inhibition of Ca2+-independent adhesion among early post-natal mouse cerebellar cells by Fab fragments of both antibodies are at least additive, when compared with equal concentrations of the individual antibodies.

Detergent extraction from rat synaptosomal plasma membranes reveals difference in mu and delta opioid receptor binding

Rat synaptosomal plasma membranes were extracted with a detergent (CHAPS, a zwitterionic derivative of cholic acid). mu and delta opioid receptor binding and adenylate cyclase activities were tested in the intact membranes and in the supernatants from detergent treated membranes. The 6000 X g/8 min. supernatant contained mu receptor binding equal to 33% of the mu receptor binding measured in the untreated membranes. When the detergent treated membranes were sedimented at (50,000 X g/10 min.), 23% of the mu receptor binding was recovered in the supernatant. After a 100,000 X g/30 min. centrifugation the supernatant contained 10% of the mu receptor binding when compared to untreated membranes. Of the delta receptor binding found in intact membranes, 10% or less was recovered in the 3 supernatants described above. Furthermore, the mu and delta receptor binding were distributed differently among particles in the supernatants. This indicates differences in the chemical properties of the mu and delta opioid receptors. Adenylate cyclase assays showed that the G/F site of this enzyme complex was inactivated in the supernatants from detergent treated membranes parallel to the delta receptor binding decrease. However, the catalytic part of adenylate cyclase was present in the supernatants and seemed resistant to the detergent.

Mouse monoclonal antibodies reacting with human brain glial fibrillary acidic protein

Three different epitopes on the glial fibrillary acidic protein (GFAP) have been identified by means of three monoclonal antibodies. The antibodies were named anti-GFAP 1, anti-GFAP 2, and anti-GFAP 3. Antibody specificities were investigated by several techniques including indirect immunoprecipitation, immunoblotting, and immunohistochemistry. The anti-GFAP 1 antibodies recognized an epitope found on GFAP from all three species tested: human, rat, and ox, but in addition a reaction was observed with cells not containing GFAP. The epitope recognized by anti-GFAP 2 was present on GFAP from human and ox, but apparently not on rat GFAP; the anti-GFAP 2 antibodies also reacted with antigen(s) other than GFAP. In contrast, the epitope defined by anti-GFAP 3 has proved absolutely specific for GFAP in human, rat, and ox.

Low cerebrospinal fluid concentration of brain-specific protein D2 in patients with normal pressure hydrocephalus

The synaptic membrane glycoprotein D2 was measured in cerebrospinal fluid (CSF) and plasma in 13 patients with normal pressure hydrocephalus (NPH), in 14 patients with primary degenerative dementia of Alzheimer type (PDD), and in 24 patients without evidence of organic nervous disease (controls). Mean CSF D2 concentration was significantly lower in NPH patients: 299 +/- 48 ng/ml (SEM) (P less than 0.001) than in PDD patients: 658 +/- 50 ng/ml (SEM) and in controls 641 +/- 45 ng/ml (SEM). Plasma D2 concentrations were higher in PDD patients compared with those found in controls. Determination of CSF D2 concentrations might be of diagnostic value in discrimination between patients with NPH and PDD patients with enlarged ventricles associated with diffuse brain atrophy.

[Effectiveness of a low-calorie diet in the postoperative period]

The characteristic feature of post-aggression metabolism is the hormone-induced metabolic changeover from anabolism to catabolism. Typically, a disturbance of glucose utilisation, enhanced lipolysis and protein catabolism are particularly prominent, all of which lead us to expect restricted utilisation of ingested food substrates. With regard to this special aspect the authors investigated in a clinical study in 10 patients with gastrectomy whether a low-calorie diet could meet energy requirements while at the same time reducing the increased glucogenesis, lipogenesis and protein catabolism. The results show that blood glucose homoeostasis is maintained without exogenous insulin supply by a daily ingestion of 1 g./kg. body weight amino acids and 4 g./kg. body weight carbohydrates, and that at the same time catabolism can be markedly reduced and that there is also no hypercatabolic increase of urea in the serum or excessive formation of triglycerides. Hence, it is considered meaningful to prescribe during the postoperative stress phase a low-calorie diet with a sufficient supply of amino acids even in case of severe trauma.

Enzyme-linked immunosorbent assay of the D2-glycoprotein

D2 is a glycoprotein enriched in neuronal membranes and probably involved in intercellular adhesion. An immunochemical relationship between D2 and the neuronal cell adhesion molecule from chick has been demonstrated. Changes in D2 concentration in human body fluids correlate to certain neurological diseases. We here report the purification of the D2 membrane proteins from fetal and adult human brain and the demonstration of physicochemical differences between the two proteins. Enrichments of 133 times (fetal D2) and 350 times (adult D2) were found. Specific rabbit antisera against the purified D2 proteins were produced, and this enabled the setting up of an enzyme-linked immunosorbent assay for D2 quantification in human brain extracts, cerebrospinal fluids, sera, and amniotic fluids.

Quantification of the D2-glycoprotein in amniotic fluid and serum from pregnancies with fetal neural tube defects

D2 is a glycoprotein existing in both membrane-bound and soluble forms. Employing a specific rabbit antibody against purified human brain D2, we developed an enzyme-linked immunosorbent assay (ELISA) for the quantification of D2 and applied it to amniotic fluids from 87 normal and 36 pathological pregnancies. With a cut-off point of 150 ng D2/ml, no false positive D2 values were obtained in any of the amniotic fluids from normal fetuses, although the alpha-fetoprotein concentrations were slightly increased in 13 cases. No false negative D2 values were found in any of the 18 investigated amniotic fluids from fetuses with anencephaly. Of 8 amniotic fluids from fetuses with spina bifida, 2 false negative D2 values were found. No false negative alpha-fetoprotein values were found in any of the cases with neural tube defects in this study. In 10 amniotic fluids from fetuses with other malformations, 5 samples showed raised D2 concentrations. The D2 level in sera from 10 women carrying normal fetuses and 16 women carrying malformed fetuses was also determined, but no statistically significant difference in D2 level was found in the pathological sera when compared with normal sera. It was concluded that the determination of D2 concentrations in amniotic fluid by means of the D2-ELISA may be used as an additional test in the screening of fetal malformations in early pregnancy.

Heteroanthracyclines. 1. 4-Demethoxyxanthodaunomycinone (6,7,9,11-tetrahydroxy-9-acetyl-7,8,9,10-tetrahydrobenzo(B)xanthen-12-one)

Two heteroanthracyclinones, namely 4-demethoxyxanthodaunomycinone (29) and its epimer 4-demethoxy-7-epixantho-daunomycinone (30), were synthesized using 2-acetyl-5,8-dimethoxytetralin (12) as starting material. Condensation of 12 with 2-methoxybenzoic acid followed by hydrolysis and oxidative cyclization gave xanthones 17 and 18 which were converted to 19 and 20 for the purpose of separation and structure assignment by dipole moment. Hydrolysis of 19 followed by alkylation with chloromethyl methyl ether and oxidation with molecular oxygen gave 26 and 27, which on acid hydrolysis gave 4-demethoxyxanthodaunomycinone (29) and 4-demethoxy-7-epixanthodaunomycinone (30). Preliminary biological assays with MCF-7, a human breast cancer cell line, showed that both 29 and 30 were weakly active while daunomycinonc, the aglycone of 2, showed no activity under similar conditions.

Immunocytochemical demonstration of the 'neuronal membrane marker' the D2-glycoprotein in human embryos

The regional distribution and cellular localization of the D2-glycoprotein in human embryonic tissues have been investigated by immunocytochemistry at the light microscope level in sections of human embryonic brain, spinal cord, some neural crest derivatives, muscle, liver and skin. the majority of neuronal membranes exhibited a positive staining reaction for D2 already in the earliest (15 mm crown-rump length) embryo examined. By 20 mm crown-rump length and later a positive staining associated with membranes of embryonic muscle, bile canaliculi, epithelial cells of the skin and choroid plexus was also observed. The D2 which is immunochemically related to the neuronal cell adhesion molecule (N-CAM), is supposed to be involved in cell adhesion phenomena. We find this suggested function less compatible with demonstrated localization of the D2-glycoprotein.

Identification of fetuin in human and rat fetuses and in other species

The fetal protein, fetuin, has previously only been identified in species belonging to the order Artiodactyla. Samples of fetal, newborn and adult human (Homo sapiens) and rat (Rattus norvegicus) plasma and tissues have been studied using three techniques: (a) crossed immunoelectrophoresis of plasma against each of four different anti-fetuin antisera (two anti-cattle, one anti-pig and one anti-sheep); (b) the peroxidase-antiperoxidase technique applied to agarose gels containing plasma spots; (c) the indirect immunoperoxidase technique applied to human fetal tissue sections. In human fetal samples all three methods gave evidence for the presence of fetuin except late in gestation and in the newborn. Adult plasma was negative. In rat fetuses only plasma was tested, by methods (a) and (b). Positive reactions were obtained for both fetal and adult samples; the fetal samples cross-reacted with several of the anti-fetuins, adult samples reacted with only one. All the fetal and embryonal plasma samples tested with the peroxidase-antiperoxidase method were positive for fetuin except for the chicken. Thus fetuin appears to be distributed in at least five mammalian orders (Artiodactyla, Primates, Rodentia, Carnivora and Perissodactyla).

Penicillamine-induced myasthenia gravis: effects of penicillamine on acetylcholine receptor

Autoimmune diseases, including myasthenia gravis, occur in patients treated with D-penicillamine. Because D-penicillamine might induce autoantibodies by the mechanism of antigenic alteration, we studied the reaction of D-penicillamine with purified acetylcholine receptor from Torpedo californica. We found that brief exposure to D-penicillamine resulted in its covalent attachment to two receptor subunits, alpha (40,000 daltons) and gamma (59,000 daltons), presumably by reduction and formation of mixed disulfides. Furthermore, D-penicillamine treatment resulted in a dramatic modification of the equilibrium acetylcholine binding properties of both purified receptor and receptor-rich membrane fragments.

Purification of the synaptic membrane glycoprotein D2 from rat brain

D2 is a nervous-specific membrane protein enriched in fractions of synaptosomal membranes from rat brain. Recently, an immunochemical relationship between D2 and the chick cell adhesion molecule (CAM) has been demonstrated. There is reason to believe that D2 is involved in adhesion phenomena between neurites. The purpose of the present study was to purify and further characterize the D2 protein from rat brain. In the developed purification procedure synaptosomal membranes from rat brains were prepared and solubilized by means of non-ionic detergent. The subsequent purification steps were hydroxylapatite chromatography, wheat germ lectin affinity chromatography, gel filtration, and lysine affinity chromatography. The purified D2 was found to be enriched 240 times compared with the starting brain homogenate and 120 times compared with the synaptosomal membrane fraction. The recovery of D2 was 26% when the amount of D2 in the synaptosomal membrane fraction was set to 100%. The purified D2 antigen was used for production of monospecific rabbit antisera, and it was found to be composed of two polypeptides of apparent molecular weights 130,000 and 150,000, respectively.

Isolation of intermediate filaments from rat astrocytes in culture

Intermediate filaments from rat astrocytes in culture were isolated by subcellular fractionation. The fractionation was monitored by electron microscopy and by quantitative immunoelectrophoresis using rabbit antibody directed against human glial fibrillary acidic protein (GFA). Morphologically intermediate filaments appeared helical with a mean diameter of 10 nm. Isolated filaments were disassembled at highly alkaline pH. After lowering of pH to slightly acidic values reassembled filaments, approximately 17 nm in diameter, were observed. As revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis the filament preparation was composed predominantly of a 51,000 molecular weight protein, corresponding to GFA. At high loads additional proteins of molecular weights 43,000 and 58,000 were detected. These latter proteins may represent residual actin and vimentin, respectively.

Responsiveness of fetal rat brain cells to glia maturation factor during neoplastic transformation in cell culture

The effect of partially purified extracts from adult pig brains containing a glia maturation protein factor (BE) has been investigated on neural cells during carcinogenesis. Pregnant BD IX-rats were given a single transplacental dose of the carcinogen ethylnitrosourea (EtNU) on the 18th day of gestation. The brains of the treated fetuses were transferred to cell culture and underwent neoplastic transformation with a characteristic sequence of phenotypic alterations which could be divided into five different stages. During the first 40 days after explantation (stage I & II) BE induced morphological differentiation of epitheloid neural cells into astrocytes. This occurred in carcinogen treated cells as well as in untreated control cultures. At the same time cells with astrocyte morphology showed accumulation of glial fibrillary acidic protein (GFA) as tested by indirect immunofluorescence with monospecific antibodies against GFA. Thereafter, in the EtNU pre-treated cultures an increased number of cells with astrocyte morphology was seen, and BE further increased the number of cells with long cytoplasmic processes. Control cells were GFA negative, while some few strongly, as well as many weakly, positive cells were seen after treatment with BE (stage III). At the later stages of neoplastic transformation the effect of BE became gradually less, and in tumourigenic cells which occurred after about 200-300 days, only a slight morphological change took place in a few cell lines. No appreciable effect on GFA-content was seen any longer, although some few weakly GFA positive cells could be observed in all permanent cell lines. Fetal rat brain cells therefore seem to become less responsive to this differentiation inducer during neoplastic transformation in cell culture.

Biochemical and ultrastructural studies of cultured rat astroglial cells: effect of brain extract and dibutyryl cyclic AMP on glial fibrillary acidic protein and glial filaments

The growth of astroglial cells in primary cultures derived from newborn rat cerebral hemispheres was investigated in the absence and in the presence of newborn rat brain extract or dBcAMP. The parameters chosen were the content of DNA, total protein, and glial fibrillary acidic protein (GFA) as well as the morphologic development of gliofilaments. During the entire culture period the DNA content increased in control culture indicating a continuous cell division, whereas the cells stopped dividing after 14 or 4 days of treatment with either brain extract or dBcAMP respectively. In contrast, a constant increase of total protein was found in both control and treated cultures. Since cell divisions had stopped in treated cultures, the increase in total protein in these cultures indicates growth of the individual cells. The GFA levels increased progressively and similarly in control cultures and in cultures treated with brain extract. The values in the treated cultures remained slightly higher than those in controls. Conversely, immediately after the addition of dBcAMP a sudden increase in GFA protein occurred and the amounts were statistically significantly different from those of the controls. The GFA levels were expressed relative to total protein indicating that GFA constitutes an increasing amount of the total protein of the individual cells during culture. The changes in the amount of GFA was shown to parallel the morphologic development of gliofilaments. Indeed, when the level of GFA increased a progressive accumulation of gliofilaments was observed. The results obtained were discussed in relation to the astrocytic maturation.

Nervous system-specific proteins in developing rat cerebral cells in culture

The nervous system-specific proteins; synaptin, D1, D2, D3, glial fibrillary acidic protein (GFA) and 14-3-2, were quantified in dissociated cerebral cells from the foetal rat brain at various times of growth in culture. By approximately 1 week in culture, the neuronal membrane markers synaptin, D1, D2, and D3 could all be demonstrated. A maximum concentration of 10-20% for synaptin, D1, and D3 and 160% for D2, in comparison with the levels in adult forebrain, was attained during the 2nd week in vitro. The astroglial gliofilament marker GFA increased continuously, reaching by 38 days of cultivation an 18-fold higher level than the concentration in adult forebrain. The neuronal cytoplasm marker 14-3-2 could be demonstrated in trace amounts, and only after more than 1 week in vitro. Neuronal cell bodies and processes stained by indirect immunofluorescence using an anti-D2 serum were strongly fluorescent after 1 week in vitro. Immunofluorescence staining for GFA revealed a cytoplasmic filamentous network in perinuclear areas and processes of, presumably, astroblasts.