Showing papers by "Radboud University Nijmegen published in 1969"
TL;DR: A detailed picture of the phospholipid composition of normal human erythrocytes and plasma was obtained by quantitative two-dimensional thin-layer chromatography on silica gel containing an alkaline component.
257 citations
TL;DR: The results strongly suggest that the (Na+-K+)-ATPase system in the stria vascularis plays the primary role in the maintenance of the cochlear cation gradients, while the contribution of Reissner's membrane to this process can only be very minor.
155 citations
TL;DR: The phospholipid composition of senile cataracts is similar to those of normal lenses of the same age and the amounts of bound lipids and of proteolipids decrease, which is an indication of membrane disintegration.
140 citations
TL;DR: The results demonstrate that the maximal tubular reabsorption capacity can be predicted with a nomogram from measurements of phosphate and creatinine in plasma and in an untimed specimen of urine, from the fasting person.
135 citations
135 citations
TL;DR: The RNase inhibitor from 100,000 g rat liver supernatant fraction has been purified 3000–4000-fold by ammonium sulfate fractionation, DEAE-Sephadex A-50 chromatography, and gel filtration on SephadeX G-100 to stabilize the polysomal profile on sucrose gradients.
93 citations
TL;DR: Findings strongly suggest that the Na-K— ATPase enzyme system in the stria vascularis plays the key role in the maintenance of the cochlear cationic gradients, while such a role appears highly unlikely for Reissner's membrane.
Abstract: Na-K-activated ATPase was determined in the cochlear structures by ultramicro-analytical methods. The highest activity was found in the stria vascularis, with a decrease from base to apex. Ouabain, which inhibits the isolated enzyme system, appeared to diminish the CMP and + EP to the same extent. These findings strongly suggest that the Na-K— ATPase enzyme system in the stria vascularis plays the key role in the maintenance of the cochlear cationic gradients, while such a role appears highly unlikely for Reissner's membrane. The CMP and +EP appear to depend on the functioning of this pump system.
75 citations
TL;DR: Experiments concerning the enzyme stability as affected by temperature and storage demonstrated that galactolipase from runner-bean leaves is quite stable.
73 citations
TL;DR: In this paper, the same authors showed that Ni(IV) flow spin d6) is surrounded by 6 S atoms in octahedral symmetry, and they obtained diamagnetic and diamagnetic diamagnetic oxide complexes of composition [Ni(bu2dtc)3]X.
Abstract: Oxidation of N,N-di-n-butyldithiocarbamato (bu2dtc) complexes of Cu(I), Ni(II), Zn(II), Cd(II) and Hg(II) is reported. Oxidation of Ni(bu2dtc)2 with Cl2, Br2, or of NiX2 (X = Cl, Br, NO3) with N,N,N′,N′-tetra-n-butylthiuram disulfide (bu4tds) gives complexes of composition [Ni(bu2dtc)3]X. These compounds are diamagnetic and dissolve in nitrobenzene as 1:1 electrolytes, their UV spectra resemble that of the iso-electronic Co(bu2dtc)3. The experimental data are in accord with the assumption that in these compounds Ni(IV) flow spin d6) is surrounded by 6 S atoms in octahedral symmetry. The analogous selenium compound tris (N, N-di-n-butyldiselenocarbamato) nickel(IV) bromide, having the same properties as the thio compounds, can also be prepared. Oxidation of Cu(bu2dtc) with Cl2 or Br2 yields paramagnetic products with the composition CuX3(bu2dtc), in which Cu also has the formal oxidation number + 4, but the structure of these compounds is still obscure. Oxidation of Zn(bu2dtc)2 and the corresponding Cd and Hg compounds yields products, the analysis of which suggests the composition MX2(bu2dtc)2 (M = Zn, Cd or Hg, X = Br or I), but infrared studies indicate that the dithiocarbamato ligands of the starting substances are oxidized to bu4tds, which in the reaction products is coordinated to the metal in its normal oxidation state + 2.
69 citations
TL;DR: No areal localization could be detected in the projection of the Olfactory bulb via the lateral olfactory tract to the ipsilateral forebrain regions and the anterior commissure appears to be considerably more limited than that of the mitral cell axons.
65 citations
TL;DR: Serum albumin has no effect on the transformations of chloroplast galactolipids, and only a part of this effect can be explained by the known capacity of serum albumin to bind free fatty acids.
TL;DR: A brief survey of the overall morphology and histological structure of the telencephalon in higher bony fishes, or Osteichthyes, to shed some light on the general forebrain organization on the basis of only a few species.
Abstract: It is the aim of this paper to provide a brief survey of the overall morphology and histological structure of the telencephalon in higher bony fishes, or Osteichthyes. This class of vertebrates is usually subdivided into the subclasses Actinopterygii and Sarcopterygii. The Actinopterygii, or rayfinned fishes, constitute by far the most abundant group of recent vertebrates. The Sarcopterygii comprise two orders, the Dipnoi and the Crossopterygii. The latter group is of particular interest because they are believed to be ancestral to the land vertebrates. Since the class Osteichthyes encompasses more than 30,000 species (a conservative estimate), a very rigorous choice is necessary in order to shed some light on the general forebrain organization on the basis of only a few species. I will essentially confine myself here to the following five species (see TABLE 1 ), by virtue of the crucial position that each of them occupies in the taxonomic scheme: 1. Polypterus senegalus, an African fresh-water fish, which according to most taxonomists, is a primitive actinopterygian ( a living relic of the ancient Palaeoniscoidei) but which some authors (e.g. Jarvik, 1942 & 1968; Daget, 1958; Poll, 1965), place in a separate subclass named the Brachiopterygii. 2. Amia calva, the bowfin, an actinopterygian from North America belonging to the order Holostei, which, at least with regard to the structure of the forebrain, is less advanced than the now dominant order of the actinopterygians, i.e., the Teleostei. 3. Neoceratodus forsteri, the Australian lungfish, which is generally considered the most primitive living dipnoan. 4. Protopterus dolloi, a species belonging to the African genus of lungfishes. 5. Latimeria chalumnae, as far as we know the only surviving crossopterygian. Prior to discussion of the peculiar, and sometimes complex, structural patterns found in the telencephalon of these fish, it may be well to comment briefly on the morphogenesis of the forebrain in general and to make a few remarks about the “generalized” telencephalon of urodele amphibians. I t may be recalled that the forebrain in an early embryonic stage is a simple tube or vesicular structure, consisting of a pair of thickened side plates which are connected dorsally, rostrally and ventrally by an epithelial membrane. During further development there occurs in most vertebrates a bulging out, or “evagination,” of the side walls. This gives rise to two hemispheres, the central ventricular spaces of which are surrounded by nervous tissue. The amphibian telencephalon is of this evaginated type, and the evagination has taken place in the rostral and caudal, as well as in the lateral, directions (FIGURES 1-3). Due to the rostral evagination, a considerable portion of the telencephalon projects in front of the membranous connection (i.e., the lamina terminalis) of the two hemispheres. FIGURES 1-3 show that in urodeles the primary olfactory center is not represented by a separate structure, but simply occupies a part of the hemisphere wall. In most other vertebrates, however, a separate evagination, starting from the rostral or lateral part of the hemisphere walls, gives rise to the formation of clearly defined olfactory bulbs.
TL;DR: Enzymatic activities for the N -demethylation of aminopyrine, the p -hydroxylation of aniline and the UDP-glucuronidation of p -nitrophenol in isolated rat hepatic cells have been compared on the basis of DNA content to those in homogenate from fresh liver tissue and the crude microsomal fractions prepared from these homogenates.
TL;DR: Results indicate that cyclic AMP is a mediator in enzyme secretion, similar to that given by 10−3 M theophylline in the isolated rabbit pancreas.
Abstract: The isolated rabbit pancreas secreted protein and α-amylase at a relatively constant rate during an eight-hour period Both pancreozymin and acetylcholine caused a massive release of protein and α-amylase into pancreatic fluid Theophylline (10−2 M) stimulated protein secretion in vitro maximally by 155%, while for α-amylase secretion a maximal average stimulation of 80% was observed Theobromine (10−2 M) exerted a slight increase on enzyme secretion, equal to that given by 10−3 M theophylline Cyclic AMP (10−3M) also increased enzyme secretion For protein secretion a maximal average stimulation of 64% was observed, while α-amylase secretion was maximally stimulated by 31% Theophylline (10−2 M) potentiated the stimulatory effect of pancreozymin (85 U/l) on pancreatic enzyme secretion These results indicate that cyclic AMP is a mediator in enzyme secretion
TL;DR: Investigations to define the epidemiological pattern of adenovirus infection in military recruits were carried out in a training centre at Ossendrecht, The Netherlands, during a 9-year period, and Adenovirus was responsible for about one third of all cases of acute respiratory illness.
Abstract: Investigations to define the epidemiological pattern of adenovirus infection in military recruits were carried out in a training centre at Ossendrecht, The Netherlands, during a 9-year period. Extensive outbreaks of adenovirus illness occurred in the winter and spring, and in some years in the late fall. The seasonal variation in total incidence of adenovirus infection as estimated by frequency of antibody rises in randomly selected recruits correlated well with that of adenovirus illness. In the cold season 20–60 of every 100 men were infected, whereas no or very little activity of adenovirus was found during the summer.Type 7 was prevalent during the first 2 years of the study period, type 21 during the next 3 years and type 4 during the last 4 years. The proportion of adenovirus infection associated with clinical illness, the distribution of adenovirus illness by week of training and the immunity of incoming recruits against adenovirus infection as estimated by frequency of neutralizing antibody were compared for type 7, type 21 and type 4.Adenovirus was responsible for about one third of all cases of acute respiratory illness. The next most common diagnostic category was influenza. Other respiratory agents (parainfluenza, RS and Coxsackie A-21 viruses, Mycoplasma pneumoniae and haemolytic streptococci) were of less importance.This work was supported in part by the United States Department of the Army through its European Research Office.We are indebted to the following persons who contributed to this study: C. P. A. van Boven, R. Brouwer, J. H. E. Custers, J. H. Dijkman, A. Prins and A. R. van der Werff, medical officers; Mr A. P. K. M. I. van Nieuwstadt, Miss M. C. J. van Nunen, Dr G. C. J. van der Ploeg and Dr H. J. A. Sonderkamp, members of the staff of our laboratory; and Misses C. H. Bronswijk, G. J. Hof, A. D. E. M. Leeuwenberg, W. T. C. J. Smulders and C. M. G. Stevens, and Mrs A. M. van Snik, technicians.Major-General Dr H. J. van der Giessen and Brigadier General W. P. Blokpoel, former Directors-General of Medical Services of the Royal Netherlands Army, and Colonel Dr B. J. W. Beunders, former Head of the Division of Preventive Medicine, granted facilities for the conduct of this study.
TL;DR: There exists a cholinergic mechanism, operating efficiently in strain C57BL and less so in strain DBA, which facilitates certain exploratory behaviours and the action of which is controlled by genetic factors.
Abstract: In this psychopharmacogenetic study, male mice of strains C57BL/6, DBA/2, and D2B6F1 received injections with four doses of the anticholinergic scopolamine and with four doses of the anticholinesterase eserine. The frequencies of four different exploratory forms of behaviour carried out in a novel environment were subsequently measured.
TL;DR: It seems that the usual criteria for detecting ovulation are less reliable in patients treated with clomiphene and that the discrepancy between ovulation and pregnancy rates can be explained in part by the occurrence of pseudoovulation resulting from theca-luteinization of an unruptured follicle.
TL;DR: In this paper, the lipid composition in cells of Bifidobacterium bifidum var. pennsylvanicus grown with and without human milk was determined so that the effect on lipids of cell wall inhibition in the absence of human milk might be assessed.
TL;DR: Arsenate and phosphate uptake by the yeast Saccharomyces cerevisiae Delft II is inhibited completely by 3 mM monoiodoacetate, 20 mM fluoride, 0.1 mM 2,4-dinitrophenol and acetate, which decreases not only the maximum rate of uptake but also the K m for this process.
TL;DR: An as yet unexplained aspect of visual pigment chemistry is the large red-shift in the absorption maximum of retinaldehyde, when it is bound to opsin in the visual pigment rhodopsin.
Abstract: AN as yet unexplained aspect of visual pigment chemistry is the large red-shift in the absorption maximum of retinaldehyde, when it is bound to opsin in the visual pigment rhodopsin. The lipoprotein opsin does not absorb in the visible and near ultraviolet, 11-cis retinaldehyde has a λmax of 376 nm (in ethanol), while cattle rhodopsin has a λmax of 498 nm. In the latter substance retinaldehyde has been shown to be bound to an amino group in opsin by a Schiff base link1. Because a retinylidene Schiff base in neutral aqueous environment has a λmax about 20 nm lower than the free aldehyde, the discrepancy with the λmax of rhodopsin is about 140 nm.
TL;DR: Implantation of corpora allata early in the fifth instar of female larvae of Locusta migratoria results in a faster development both during the last instar and the adult somatic growth period, and theAdult locusts attain a significantly higher maximum wet weight.
Abstract: Implantation of corpora allata early in the fifth instar of female larvae of Locusta migratoria results in a faster development both during the last instar and the adult somatic growth period. The adult locusts attain a significantly higher maximum wet weight. The increase in dry weight, however, is smaller than in control insects. So the high titer of corpus allatum hormone results in a considerably higher water content.
In CA-implanted locusts the growth of the indirect dorsal longitudinal flight muscles is inhibited and the protein content is lower as compared with control specimens. Especially the differentiation of these muscles is strongly inhibited. A hypothesis for a regulation of the indirect flight muscle development by the changing titer of the corpus allatum hormone is proposed.
During the second part of the adult period investigated the high titer of the corpus allatum hormone strongly diminishes the growth of the fat body, but the protein content is not altered in comparison with the normal developing fat body. The data reveal that the influence of an induced high titer of corpus allatum hormone on protein metabolism in the flight muscles is different from that in the fat body.
ZUSAMMENFASSUNG
DIE WIRKUNG VON CORPORA ALLATA-IMPLANTATION AUF DIE ENTWICKLUNG DER FLUGMUSKELN UND DES FETTKORPERS BEI LOCUSTA MIGRATORIA
Nach Corpora allata-Implantation am Anfang des L5 von weiblichen Larven von Locusta migratoria folgt eine schnellere Entwicklung sowohl im letzten Larvenstadium als auch in der adulten somatischen Wachstumsperiode. Die adulten Heuschrecken erreichen ein signifikant hoheres Frischgewicht-Maximum. Die Zunahme des Trockengewichts ist jedoch geringer als bei Kontrollen. Der hohe Titer an Corpus allatum-Hormon resultiert also in einem betrachtlich hoheren Wassergehalt.
Der Zuwachs der indirekten dorsalen Flugmuskeln ist in mit Corpora allata implantierten Heuschrecken gehemmt und der Eiweisgehalt ist niedriger als bei Kontrollen. Besonders die Differenzierungsphase der Muskeln ist stark gehemmt. Es wird eine Hypothese uber die Regulation der Entwicklung indirekter Flugmuskeln durch den sich andernden Titer des Corpus allatum-Hormons aufgestellt.
Wahrend des zweiten Teils der untersuchten adulten Periode nimmt das Wachstum des Fettkorpers unter dem Einfluss des hohen Hormontiters ab, aber der Proteingehalt dieses Gewebes andert sich im Vergleich zu dem sich normal entwickelnden Fettkorper nicht.
Diese Daten zeigen, das der Einfluss eines induzierten hohen Titers an Corpus allatum-Hormon beim Proteinstoffwechsel in den Flugmuskeln anders ist als im Fettkorper.
01 Jan 1969
TL;DR: This chapter presents the mechanism of the visual process, which shows that in man there is no detectable change in rhodopsin concentration upon extinction of an ordinary room light, while the sensitivity of the eye increases hundredfold.
Abstract: Publisher Summary This chapter presents the mechanism of the visual process. The cis-trans isomerization of retinaldehyde exposes a catalytic center, thereby making rhodopsin an enzymatically active substance. The logical place for the pigment molecules is in the rod sac membrane, as the intrasaccular space is electronoptically empty and disappears virtually completely after exposure of the rods to a hypertonic medium. Rhodopsin is transparent to orange light but absorbs green light, a change in the intensity of the reflected green light represents a change in rhodopsin concentration, which shows that in man there is no detectable change in rhodopsin concentration upon extinction of an ordinary room light, while the sensitivity of the eye increases hundredfold. Rhodopsin upon illumination immediately initiates visual excitation by releasing an electronic charge carrier and loses the ability through isomerization to prelumirhodopsin, and every chemical step of the photolytic cycle, including the initial isomerization to lumirhodopsin, is an adaptive process. The all- trans -retinaldehyde liberated from its original bond to opsin forms a Schiff base with an amino group in the rod sac membrane, thereby causing a greatly increased cation leakage. The recovery rate of the rod sac cation gradients determines the sensitivity changes during light adaptation
TL;DR: Results indicated that, in the m.
Abstract: 1.
In a group of female rats the fast m. plantaris was overexerted by denervating the m. gastrocnemius and m. soleus. Part of these rats were trained systematically on a motor-driven endless belt set at an inclination.
2.
Isometric contraction characteristics were studied in these and in control rats.
3.
Muscle weight and tetanic muscle force of the experimental group both increased to about 130% of that of control rats of the same age.
4.
Training had no additional effect on the mechanical characteristics studied in the muscles of the denervated rats.
5.
The results indicated that, in the m. plantaris of the denervated group, no changes occurred in the twitch contraction time nor in the tetanic force per unit of weight.
6.
A comparison is made with the findings on slow muscles as reported in the literature.
TL;DR: It is suggested that either the basophils 3 or the caudal chromophobic cells have a corticotropic function in the distal lobe of male common frogs.
Abstract: The effects of metopirone and aldactone on the histology of the pars distalis of the pituitary, the interrenal gland and the interstitial tissue of the testis were studied in male common frogs. Activation of the interrenal tissue by these substances was paralleled by a stimulation of one of the tinctorial cell types in the distal lobe namely the basophils 3 and of caudal chromophobic cells. Simultaneously a regression of the interstitium testis was observed. It is suggested that either the basophils 3 or the caudal chromophobic cells have a corticotropic function.
TL;DR: It is concluded that the apo- and holoenzyme do not differ in overall protein conformation and the broad band between 300 and 450 mμ in the circular-dichroism spectrum of holoen enzyme is probably composed of at least two components: the charge-transfer complex between NAD+ and the reactive -SH group of the protein.
TL;DR: It is suggested that the antibody deficiency syndrome in this case was based on a familial congenital disturbance in IgM synthesis, and the boy subsequently developed autoimmune haemolytic anaemia.
Abstract: Summary
This paper describes a boy who suffered from severe recurrent infections from the first year of life. A brother with similar symptoms died from meningococcal meningitis. Virtually no IgM was demonstrable in the patient's serum, and it is suggested that the antibody deficiency syndrome in this case was based on a familial congenital disturbance in IgM synthesis. A study of antibody formation disclosed that disturbances existed in the formation of antibodies assumed to be contained in IgM; other antibodies were produced in adequate amounts. The significance of these findings is discussed in some detail. The boy subsequently developed autoimmune haemolytic anaemia. The question whether this was caused by the IgM deficiency or whether the immunological imbalance was based on a general disorder must remain unanswered.
TL;DR: In this article, the hyperon-nucleon scattering is described by a potential model, and the position and the ϵ-Sigma+p$ scattering data are combined with the ε-Lambda scattering data to determine the effective range.
Abstract: The hyperon-nucleon scattering is described by a potential model. The ${\ensuremath{\Sigma}}^{+}p$ scattering data require a $^{3}S_{1}$ resonance in the $\ensuremath{\Lambda}p$ scattering, for which resonance there seems to be experimental evidence. Its position and the ${\ensuremath{\Sigma}}^{+}p$ scattering data determine the ${\ensuremath{\Sigma}}^{+}p$ effective-range parameters, and combined with the $\ensuremath{\Lambda}p$ scattering data it determines the $\ensuremath{\Lambda}p$ effective-range parameters.
TL;DR: A patient with severe mental retardation, generalized convulsions and electro‐encephalo‐graphic abnormalities has been described, and a marked carnosinuria was observed on a regular diet as well as on a diet which was essentially free of carnosine.
Abstract: Summary
A patient with severe mental retardation, generalized convulsions and electro-encephalo-graphic abnormalities has been described A marked carnosinuria was observed on a regular diet as well as on a diet which was essentially free of carnosine No carnosine was found in plasma of this patient on any occasion The serum-carnosinase activity was extremely diminished compared to control subjects Oral loading with L-carnosine resulted in a much greater excretion of the administered L-carnosine compared to a control subject The consanguineous parents of the patient also excreted large amounts of the dipeptide and had decreased serum-carnosinase activities Infusion with freshly prepared donor plasma, containing active carnosinase, resulted in a temporary elevation of the enzymic activity in serum and a decrease of carnosine excretion in urine
TL;DR: The Symposium was devoted primarily to the biochemistry of the proteins of the lens, and the chemical and physiological structure, the immunological reactions of the water soluble and water insoluble lens proteins was discussed.
TL;DR: From a comparison of the differential and difference titration curves of substituted hemoglobin with those of unsubstituted hemoglobin, it is concluded that 2 of the 4 α-amino groups are alkaline Bohr groups.