bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Catechol‐O‐Methyltransferase by 6,7‐Dihydroxy‐3,4‐Dihydroisoquinolines Related to Dopamine: Demonstration Using Liquid Chromatography and a Novel Substrate for O‐Methylation
Authors: Cheng Bhi Y. , Origitano Thomas C. , Collins Michael A.
Published: October 2006

Abstract: We report that 6,7‐dihydroxy‐3,4‐dihydroisoquinolines related to dopamine are potent inhibitors of catechol‐O‐methyltransferase (COMT), but are not apparent substrates for the enzyme in vitro or in vivo. Three dihy‐droxy (catecholic) dihydroisoquinolines, including the 1‐benzyl (DesDHP) and the 1‐methyl (DSAL) analogs, were found to inhibit COMT activity in rat liver supernatant more effectively than the well‐known inhibitor, tropolone. Inhibition of O‐methylation was uncompetitive with substrate, and O‐methylated products of the catecholic dihydroisoquinolines were undetectable. For these in vitro studies, a facile liquid chromatographic assay was developed utilizing as a site‐specific substrate, 1‐methyl‐6,7‐dihydroxy‐tetrahydroisoquinoline‐1 ‐carboxylate (salsolinol‐1‐carboxylate). This catechol produces only one phenolic product isomer when incubated with liver supernatant and S‐adenosylmethionine. Following central injection of DSAL in rats, inhibition of brain COMT in vivo was indicated by the reduced brain levels of homovanillic acid, but not of 3,4‐dihydroxyphenylacetic acid. Furthermore, O‐methylated DSAL metabolites could not be detected in brain by liquid or gas chromatography. We suggest that 6,7–dihydroxy‐dihydroisoquinolines are “nonmethylatable” COMT inhibitors because they exist as quinoidal tautomers resembling pyridones or tropolones rather than as catechols. Quinoid formation is supported by the fluorescence and ultraviolet spectra for DSAL and its O‐methyl derivatives. The experiments reveal a new class of COMT inhibitors that may be of pharmacological and mechanistic value. Additionally, 3,4‐dihydroisoquinolines could arise endogenously via oxidation of the 1,2,3,4‐tetrahydroisoquinolines which are ingested or produced from cellular catecholamine condensations. However, it is unlikely that dihydroisoquinoline (e.g., DSAL) concentrations necessary to inhibit COMT significantly would be attained via endogenous pathways.
Metabolism of Phosphate and Sulfate Groups Modifying the P0 Protein of Peripheral Nervous System Myelin
Authors: Toews Arrel D. , Fischer Helen R. , Goodrum Jeffry F. , Windes Susan , Morell Pierre
Published: October 2006

Abstract: We have examined the metabolism of phosphate and sulfate groups modifying the P0 protein, the major protein of peripheral nervous system myelin, using an in vitro incubation system. Incorporation of [3H]leucine into the P0 peptide backbone decreased ∼25‐fold between 10 and 90 days of age, a finding reflecting a decreased rate of myelin synthesis in the older animals. In contrast, incorporation of [32P]phosphate into P0 decreased only four‐ to fivefold, a result indicating that phosphate groups are metabolized independently of the peptide backbone. Developmental decreases in the incorporation of sulfate groups into P0 were similar to those seen for leucine, an observation suggesting that this modifying group is metabolized together with the peptide backbone as a single metabolic entity. The time course of labeling of P0 isolated from the starting homoge‐nate and from myelin was also compared. Results are consistent with sulfation of P0 protein taking place before insertion of newly synthesized P0 into myelin. In contrast, incorporation of phosphate into P0 appears to involve both the newly synthesized pool and the preexisting pool of P0 in myelin. Presumably, entry of phosphate into P0 in myelin involves turnover of preexisting phosphate groups and re‐phosphorylation by myelin protein kinases. Developmental decreases in the specific activity of P0 phosphate groups in myelin are consistent with the presence of a small, rapidly turning‐over pool of phosphorylated P0 (perhaps associated with the axon‐myelin interface), which does not increase to the same extent as the marked increase in bulk myelin that occurs during development.
Partial Sequence of MAP2 in the Region of a Shared Epitope with Alzheimer Neuronbrillary Tangles
Authors: Kosik Kenneth S. , Orecchio Lisa D. , Bakalis Shelley , Duffy Lawrence , Neve Rachael L.
Published: October 2006

Abstract: A 3.3‐kilobase DNA complementary to human microtubule‐associated protein 2 (MAP2) was sequenced by the dideoxy method. The 3’end terminates at an internal EcoRI site before the polyA tail. Due to the arrangement of the cDNA insert in the λX gt 11 vector, the MAP2 fragment is not fused to β‐galactosidase when expressed. The Chou Fasman algorithm for the initial 58 amino acids from the first in‐frame methionine predicts an α helix. Beyond this point, a series of turns is predicted until amino acid 160. The frequent presence of basic residues in proximity to serines or threonines is consistent with multiple phosphorylation sites. The minimum specificity determinant for Ca2+/calmodulin‐dependent kinase is repeated 13 times. The sequence of a region containing a MAP2 epitope that is shared with the Alzheimer neuronbrillary tangle was determined by DNase treatment of the cDNA and antibody selecting the small resultant clones in a λ gt 11 sublibrary. Likewise, a MAP2 epitope that is not shared with the neurofibrillary tangle also has been located. Both epitopes are in the projection portion of the molecule. A bovine MAP2 cyanogen bromide fragment, which contains the epitope shared with the neurofibrillary tangle, is partially insoluble under aqueous conditions, probably due to the aggregation of oppositely charged residues. Thus, rapid cleavage of MAP2 to small peptides is probably necessary in vivo to prevent the aggregation of larger cleavage fragments.
Subcellular Localization and Characterization of Vasopressin Binding Sites in the Ventral Septal Area, Lateral Septum, and Hippocampus of the Rat Brain
Authors: Poulin Paule , Lederis Karl , Pittman Quentin J.
Published: October 2006

[Arg8]‐Vasopressin (AVP) has been shown to exert characteristic central physiological actions in the ventral septal area of the rat brain. This study reports the characterization of receptors for AVP in synaptic plasma membranes prepared from the ventral septal area, the lateral septum, and the hippocampus. Binding of [3H]AVP was temperature and time dependent, linearly related to protein concentration, saturable, and specific. Scatchard plot analysis suggested the presence of a population of binding sites in the three brain areas with dissociation constants and maximal binding capacities, respectively, of 1.06 ± 0.39 nM and 24.0 ± 7.01 fmol/mg of protein (mean ± SEM; n = 3) for the ventral septal area, 0.92 ± 0.13 nM and 47.0 ± 4.96 fmol/mg of protein (n = 3) for the lateral septum, and 0.91 ± 0.14 nM and 25 ± 5.02 fmol/mg of protein (n = 3) for the hippocampus. In all three brain regions, the rank order of potencies of several vasopressin analogs, unrelated peptides, and other compounds for competitive displacement of ligand indicated a receptor with properties resembling those of the V1‐like receptor for AVP. These data document the presence of a high‐affinity, V1‐like vasopressin receptor in the rat ventral septal area for which the pharmacological properties are similar to those previously reported in physiological studies.
Identification of α2‐Adrenergic Receptors in Chicken Pineal Gland Using [3H]Rauwolscine
Authors: Bylund David B. , Rudeen P. Kevin , Petterborg Larry J. , Ray‐Prenger Carla
Published: October 2006

The norepinephrine‐induced inhibition of avian pineal N‐acetyltransferase activity appears to be mediated by α2‐‐adrenergic receptors. In this study, α2‐adrenergic receptors in the chicken pineal gland were directly identified by radioligand binding. Membrane preparations of pineal glands from chickens from 1 to 6 weeks of age were examined using [3H]rauwolscine, a selective α2‐adrenergic receptor antagonist, to characterize the binding sites. The results indicate no ontological change in either the affinity (KD) or density of receptor binding sites (Bmax) during the time span examined. The binding was saturable and of high affinity with a mean KD of 0.27 ± 0.01 nM and a mean Bmax of 242 ± 12 fmol/mg protein. Further characterization of these binding sites indicated that the α2‐adrenergic receptor is of the α2A subtype, since prazosin and ARC‐239 bound with low affinities and oxymetazoline bound with high affinity.
Axonal Transport in the Garfish Optic Nerve: Comparison with the Olfactory System
Authors: Cancalon Paul F.
Published: October 2006

Fast and slow axonal transports were studied in the optic nerve of the garfish and compared with previous studies on the olfactory nerve. The composition of fast‐transport proteins was very similar in the two nerves. Although the velocity of fast transport was slightly lower in the optic nerve, there was a linear increase in velocity with temperature in both nerves. As in the olfactory nerve, only a single wave of slow‐transport protein radioactivity moves along the nerve. The velocity of slow transport also increased linearly with temperature, but the coefficient was less than in the olfactory system. The composition of slow transport in the optic nerve was significantly different from that in the olfactory nerve, a finding reflecting the different cytoskeletal constituents of the two types of axons. The slow wave could be differentiated into several subcomponents, with the order of velocities being a 105‐kilodalton protein and actin > tubulins and clathrin > fodrin ≫ neurofilaments. It can be concluded that the temperature dependence of fast and slow axonal transport in different nerves reflects the influence of temperature on the individual polypeptides constituting the various transport phases. The garfish optic nerve preparation may be advantageous for studies of axonal transport in retinal ganglion cell axons, because its great length avoids the complications of having to study transport in the optic tract or in material accumulating at the tectum.
Opioid Receptors in Magnesium‐Digitonin‐Solubilized Rat Brain Membranes Are Tightly Coupled to a Pertussis Toxin‐Sensitive Guanine Nucleotide‐Binding Protein
Authors: Wong Yung H. , Demoliou‐Mason Catherine D. , Barnard Eric A.
Published: October 2006

Abstract Opioid receptors solubilized in Mg2+‐digitonin (2%, wt/vol) from Mg2+‐pretreated rat brain membranes maintain, in addition to high‐affinity opioid agonist binding, the modulation by guanine nucleotides. One of the modes of expression of the latter property is an attenuation of agonist binding by guanine nucleotides in the presence of Na+. To investigate the molecular basis of this modulation and to identify the G protein(s) involved, the soluble receptors were [32P]ADP‐ribosylated by means of Bordetella pertussis toxin and subjected to molecular size exclusion chromatography. In addition, soluble extracts were chromatographed on lectin and hydrophobic affinity columns. The binding of 35S‐ and 3H‐labelled analogues of GTP was also monitored in the species separated. The oligomeric G protein‐coupled opioid receptors and the guanine nucleotide/pertussis toxin‐sensitive species showed similar chromatographic properties in all three systems. This indicates that the biochemically functional G protein‐opioid receptor complex formed in Mg2+‐pretreated membranes in the absence of an agonist is stable in digitonin solution and to chromatographic separation. Further analysis showed that the guanine nucleotide modulation of opioid receptors is via the pertussis toxin substrates with Mr of 41,000 and 39,000, which are identified as Gi and Goα subunits, respectively.
Purified Rat Brain Microvessels Exhibit Both Acid and Neutral Sphingomyelinase Activities
Authors: Carré Jean‐Baptiste , Morand Olivier , Homayoun Parvin , Roux Françoise , Bourre Jean‐Marie , Baumann Nicole
Published: October 2006

Abstract Purified rat brain microvessels have been shown to hydrolyze radiolabeled sphingomyelin by means of two different enzyme systems. Enzymatic activity was detected at pH 7.4 and was strongly stimulated by magnesium or manganese and inhibited by calcium. Activity at pH 5.1 could also be found and was not dependent on any of these cations. At neutral pH and in the presence of magnesium, the rate of sphingomyelin hydrolysis did not exhibit a linear relationship with protein concentration. In contrast, increasing the protein concentration from 0.05 to 0.5 mg/ml resulted in a constant increase of sphingomyelin hydrolysis at pH 5.1. Kinetic parameters of both neutral and acid activities have been determined and were similar in magnitude to values reported previously for neural sphingomyelinases. This work demonstrates the occurrence of a neutral sphingomyelinase activity in purified rat brain microvessels, an observation raising the question of its role at the level of the blood‐brain interface.
Cysteine: Depolarization‐Induced Release from Rat Brain In Vitro
Authors: Keller Hans Jörg , Do Kim Quang , Zollinger Markus , Winterhalter Kaspar H. , Cuénod Michel
Published: October 2006

Abstract: Compounds released on depolarization in a Ca2+‐dependent manner from rat brain slices were screened to identify candidates for neuroactive substances. Lyophilized superfusates were analyzed by reversed‐phase HPLC after derivatization with 9‐fluorenyl N‐succinimidyl carbonate. One of the compounds that showed an increase of concentration in superfusates in the presence of iodoacetamide was identified as the cysteine (Cys) derivative, S‐carboxamidomethylcysteine, by fast atom bombardment mass spectrometry and other methods. This stable Cys derivative originates from endogenous, extracellular Cys. The finding led to a method for quantification of Cys in superfusates by immediate cooling of the superfusates to 0°C and reaction of Cys with N‐ethylmaleimide. Depolarization‐induced Ca2+‐dependent release of Cys was most prominent in the neocortex, followed by the mesodiencephalon, striatum, and cerebellum. This suggests that Cys is released from a neuronal compartment and might be involved in neurotransmission.
A Monoclonal Antibody Raised Against Plasma Membrane of Cholinergic Nerve Terminals of the Torpedo Inhibits Choline Acetyltransferase Activity and Acetylcholine Release
Authors: Eder‐Colli L. , Briand P. A. , Pellegrinelli N. , Dunant Y.
Published: October 2006

Abstract: Monoclonal antibodies were raised against the synaptosomal plasma membranes (SPMs) purified from the electric organ of the Torpedo. One antibody that reacts preferentially with SPMs rather than with other membrane fractions isolated from this tissue was previously found to inhibit hydrophilic and amphiphilic choline‐O‐acetyltransferase (ChAT) activity. On immunoblots of SPMs, this antibody ecognizes two polypeptides of 135 and 66 kilodaltons that are related; the 66‐kilodalton polypeptide appears to exist as a monomer and as a dimer in SPMs. The antibody was also able to inhibit the calcium‐dependent release of acetylcholine in Torpedo synaptosomes without affecting the total neurotransmitter content. This inhibition was dependent on the antibody concentration and was observed when the release was elicited by either KC1 depolarization or the calcium ion‐ophore A23187; this suggests that inhibition was not mediated by a blockage of the depolarization‐activated calcium influx. The inhibition could not be prevented by atropine, a result indicating that the antibody does not block release by mimicking the action of acetylcholine on presynaptic muscarinic autoreceptors. Thus, the antigen recognized by this antibody appeared to be involved in acetylcholine release; this antigen could be membrane‐bound ChAT, another protein of the SPMs, or both.
Epidermal Growth Factor Enhances the Expression of an Endogenous Lectin in Aggregating Fetal Brain Cell Cultures
Authors: Tenot Michè , Kuchler Sabine , Zanetta Jean‐Pierre , Vincendon Guy , Honegger Paul
Published: October 2006

Abstract: Aggregating cell cultures prepared from fetal rat telencephalon express the two subunits [cerebellar soluble lectins (CSL) 1 and 2] of a soluble, mannose‐specific endogenous lectin (CSL) in a development‐dependent manner. Increased CSL synthesis was found at an early postmitotic stage as well as during the period of maximal myelination. Repet‐tive treatment of early cultures with epidermal growth factor EGF, 3 nM) caused a great stimulation of CSL biosynthesis. Immunocytochemical studies revealed particularly intense CSL‐specific staining in small, EGF‐responsive cells, presumably glial cells. Large quantities of CSL‐immunoreactive material were found also in the extracellular space and on the external side of the plasma membrane, indicating abundant release of CSL. The present findings suggest that EGF or EGF‐related factors in the brain are able to regulate the expression of an endogenous lectin, affecting brain ontogeny.
Diurnal Variation in the Function of Serotonin Terminals in the Rat Hypothalamus
Authors: Blier Pierre , Galzin Anne‐Marie , Langer Salomon Z.
Published: October 2006

Abstract: The high‐affinity binding of [3H]imipramine is associated with the serotonin (5‐hydroxytryptamine; 5‐HT) transporter in the brain and in platelets. In the rat hypothalamus it has been reported that the density of these sites is increased in the dark period of the day, and this could result in an alteration in the release of 5‐HT. The electrically evoked release of [3H]5‐HT was thus studied in preloaded hypothalamic slices prepared from rats kept under 12:12 h light/dark or dark/light schedules. The fractional release of [3H]5‐HT evoked by electrical stimulation, but not by the 5‐HT releasing agent fenfluramine, was significantly decreased during the dark period when compared with the light period. The effects of the 5‐HT reuptake blocker citalopram, of the two 5‐HT autoreceptor agonists 5‐methoxytryptamine and RU 24969, and of the 5‐HT autoreceptor antagonist methiothepin on the release of [3H]5‐HT were the same in both groups of rats. In conclusion, the release of [3H]5‐HT from prelabelled rat hypothalamic slices is decreased during the dark period of the day. This modification is not reflected by changes in the effects of citalopram, an inhibitor of 5‐HT reuptake, to modify the overflow of [3H]5‐HT. The sensitivity and efficacy of agonists of the 5‐HT autoreceptor are the same during the light and dark periods of the day.
Sensitive Radioimmunoassays for Histamine and tele‐Methylhistamine in the Brain
Authors: Garbarg M. , Pollard H. , Trung Tuong M. D. , Schwartz J. C. , Gros C.
Published: October 2006

Abstract: Serum albumin conjugates of histamine or tele‐methylhistamine, a major catabolite, were prepared using 1,4‐benzoquinone as the coupling agent and used to raise polyclonal antibodies in rabbits. The same reagent was used to prepare the [125I]iodinated tracer and treat tissue extracts submitted to the radioimmunoassays. The IC50 values of prederivatized histamine and tele‐methylhistamine in the radioimmunoassays were 0.3 nM and 0.5 nM, respectively, whereas nonderivatized histamine or tele‐methylhistamine, histidine, a variety of histamine derivatives, amines, etc., had at least 1,000‐fold higher IC50 values. Application of the radioimmunoassays to nonpurified extracts of rat brain allowed the quantification of the two amine immunoreactivities in samples corresponding to less than 1 mg of hypothalamus. The tissue immunoreactivity corresponded to authentic histamine or tele‐methylhistamine, as shown by (a) the parallel 125I‐tracer displacement curves, (b) the similar elution patterns from HPLC columns, (c) the regional levels of histamine and tele‐methylhistamine in brain, similar to those obtained with other methods, and (d) the clearcut effects of treatments with inhibitors of l‐histidine decarboxylase or monoamine oxidase. The two radioimmunoassays appear as simple and sensitive tools to evaluate steady‐state levels and turnover rates of histamine and tele‐methylhistamine
Tryptophan Availability Modulates Serotonin Release from Rat Hypothalamic Slices
Authors: Schaechter Judith D. , Wurtman Richard J.
Published: October 2006

Abstract: Application of a novel in vitro experimental system has allowed us to describe the relationship between tryptophan availability and serotonin release from rat hypothalamic slices. Superfusing hypothalamic slices with a physiologic medium containing l‐tryptophan (1, 2, 5, or 10 μM) caused dose‐dependent elevations in tissue tryptophan levels; the magnitude of the elevations produced by supplementing the medium with <5 μM tryptophan was within the physiologic range for rat brain tryptophan levels. Slice serotonin levels rose biphasically as the tryptophan concentration in the medium was increased. Superfusing the slices with medium supplemented with a low tryptophan concentration (1 or 2 μM) caused proportionally greater incremental changes in serotonin levels than the increases caused by further elevating the tryptophan concentration (5 or 10 μM). The spontaneous release of serotonin from the slices exhibited a dose‐dependent relationship with the tryptophan concentration of the super‐fusion medium. Electrically evoked serotonin release, which was calcium‐dependent and tetrodotoxin‐sensitive, also increased in proportion to the medium tryptophan concentration. These data suggest that the rate at which serotonin is released from hypothalamic nerve terminals is coupled to brain tryptophan levels. Accelerations in hypothalamic serotonin synthesis, caused by elevating brain tryptophan levels, result in proportionate increases in the rates of serotonin release during rest and with membrane depolarization.
Effects of Lactic Acidosis on the Function of Cerebral Cortical Synaptosomes
Authors: White Elizabeth J. , Juchniewicz Henryk J. , Clark John B.
Published: October 2006

Abstract: Synaptosomes exposed to anoxic insult produce lactate at a slow rate (measured over 60 min). No measurable damaging effects were produced by prolonged depolarisation, anoxic insult, or exogenous lactate (2–32 mM) either on the synaptic plasma membrane (as judged by release of lactate dehydrogenase and soluble proteins), or on synaptosomal phospholipases (as judged by choline release from membrane phospholipids). Potassium‐stimulated acetylcholine release was decreased by incubation in the presence of lactate (2–32 mM), as was potassium‐ and veratrine‐stimulated calcium uptake and the calcium content of depolarised synaptosomes. The intrasynaptosomal pH was also reduced but there was no stimulation of oxygen radical production (as judged by H2O2 generation) by exogenous lactate. The role that lactic acidosis may play in giving rise to the altered calcium homeostasis and decreased acetylcholine release from synaptosomes exposed to anoxic insult is discussed.
Effect of Age on Brain Cortical Protein Kinase C and Its Mediation of 5‐Hydroxytryptamine Release
Authors: Friedman Eitan , Wang Hoau‐Yan
Published: October 2006

Abstract: The effects of age on the activity and translocation of protein kinase C (PKC) and on the facilitation of 5‐hydroxytryptamine (5‐HT, serotonin) release induced by PKC activation with the phorbol ester phorbol 12‐myristate 13‐acetate were investigated. The activities of cortical PKC and its translocation in response to K+ depolarization and phorbol ester stimulation were reduced during aging in Fischer‐344 rats. Parietal cortical brain slices from 6‐, 12‐, and 24‐month‐old animals were preloaded with [3H]5‐HT and release was evoked by 65 mM K+ or the calcium ionophore A23187. 5‐HT release induced by either K+ or A23187 was found to be reduced in 12‐ and 24‐month‐old as compared to 6‐month‐old animals. This decrease was not reversed by high extracellular Ca2+. Activation of PKC resulted in a facilitated transmitter release in tissue from 6‐ and 12‐month‐old animals but reduced [3H]5‐HT release in slices from 24‐month‐old animals. These responses were prevented by the putative PKC inhibitor 1‐(5‐isoquinolinesulfonyl)‐2‐methylpiperazine (H‐7), but not by increasing extracellular or intracellular Ca2+. The results demonstrate an age‐related change (1) in brain PKC activity and translocation and (2) in a physiological response to PKC stimulation. These results may have implications for other PKC‐mediated functions that are altered during senescence.
Localization and Characterization of Binding Sites with High Affinity for [3H]Ouabain in Cerebral Cortex of Rabbit Brain Using Quantitative Autoradiography
Authors: Antonelli Marta C. , Baskin Denis G. , Garland Miriam , Stahl William L.
Published: October 2006

Abstract: [3H]Ouabain binding was studied in sections of rabbit somatosensory cortex by quantitative autoradiography and in rabbit brain microsomal membranes using a conventional filtration assay. KD values of 8–12 nM for specific high‐affinity binding of [3H]ouabain were found by both methods. High‐affinity binding was not uniformly distributed in somatosensory cortex and was localized predominantly to laminae 1,3, and 4. [3H]Ouabain binding in tissue sections was stimulated by the ligands Mg2+/Pi or Mg2+/ATP/Na+ and was inhibited by K+ (IC50= 0.7–0.9 mM), N‐ethylmaleimide, 5,5′‐dithiobis(2‐nitrobenzoic acid), and erythrosin B. We conclude that [3H]ouabain is reversibly and specifically bound with high affinity in rabbit brain tissue sections under conditions that favor phosphorylation of Na+,K+‐ATPase. Quantitative autoradiography is a powerful tool for assessing the affinity and number of specific ouabain binding sites in brain tissue.
Islet‐Activating Protein Inhibits the β‐Adrenergic Receptor Facilitation Elicited by γ‐Aminobutyric AcidB Receptors
Authors: Wojcik Walter J. , Ulivi Massimo , Paez Ximena , Costa E.
Published: October 2006

γ‐Aminobutyric acidB (GABAB) receptor recognition sites that inhibit cyclic AMP formation, open potassium channels, and close calcium channels are coupled to these effector systems by guanine nucleotide binding proteins (G proteins). These G proteins are ADP‐ribosylated by islet‐activating protein (IAP), also known as pertussis tokin. This process prevents receptor coupling to these G proteins. In slices of cerebral cortex and hippocampus from rat, stimulation of GABAB receptors with baclofen, a receptor agonist, also potentiates the accumulation of cyclic AMP stimulated by β‐adrenergic agonists. It was unknown whether those GA‐BAB receptors that potentiate the β‐adrenergic response were also sensitive to IAP. IAP was injected intracerebroventric‐ularly into rats to ADP‐ribosylate IAP‐sensitive G proteins. Four days after the IAP injection, 38% and 52% of these G proteins from cerebral cortex and hippocampus, respectively, were ADP‐ribosylated by the IAP injection. In slices of both structures prepared from IAP‐treated rats, the GABAB receptor‐mediated potentiation of the β‐adrenergic receptor response was attenuated. Thus, many GABAB receptor‐mediated responses are coupled to IAP‐sensitive G proteins.
Interrelationships (Between Glucose Metabolism, Energy State, and the Cytosolic Free Calcium Concentration in Cortical Synjaptosomes from the Guinea Pig
Authors: Kauppinen Risto A. , Taipale Hannu T. , Komulainen Hannu
Published: October 2006

The stoichiometrics of glycolysis and pyruvate oxidation were determined in cortical synaptpsomes under varying rates of ATP consumption. Glycolysis was measured by using D‐3‐[3H]glucose as a marker and pyrujvate oxidation by using D‐3,4‐[14C]glucose, which has to be metabolized to l‐[14C]pyruvate before being decarboxylated by the pyruvate dehydrogenase complex of intrasynaptosomal mitochondria. Cytosolic free Ca2+ concentration ([Ca2+]c) wis determined in parallel and was manipulated by using EGTA in the incubation. The results show that in nonstimulated synapto‐somes glycolysis and pyruvate oxidation are tightly coupled and stoichiometric. In the absence of Ca2+, when [Ca2+]c drops from 260 nM to 40 nM, glucose utilization increases, following the increase in energy demand, which has been shown to be due to elevated Na+ cycling. KC1 depolarization, ve‐ratridine, and a mitochondrial uncoupler, carbonyl cyanide m‐chlorophenylhydrazone, all stimulate glycolysis and pyruvate oxidation stoichiometrically, independently of the presence of external Ca2+. A rise in [Ca2+]c, therefore, is not required to regulate mitochondrial pyruvate metabolism. It is concluded that synaptosomes exhibit a high degree of respiratory control, that they rely on glucose oxidation for their energetics, and that stimulation of energy production can be achieved independently of changes in [Ca2+]c.
The Protein Problem of China
Authors: Adolph William H.
Published: October 2006

(1) The protein intake of China is approximately 80 grams per capita per day, 5 per cent. of which is animal protein. (2) The lower digestibility of the protein in vegetarian diets causes the effective protein intake to be much less than is indicated by this figure. (3) Attempts in the laboratory to devise an adequate diet using foods from vegetarian sources only have not met with marked success. (4) The use of mixed cereals in the diet has provided protein of higher biological value; this habit may reflect the attempt on the part of the rural peoples to work out a more effective protein intake. (5) It is suggested that in China some of the cereal protein in the dietary intake be replaced by more leaf vegetable protein. (6) The question is raised as to how far it is feasible in the war economy to replace animal protein by vegetable protein. (7) In long-term plans for food relief in the Far East it is urged that an emphasis be placed on the protein factor.
The Golden Hamster (
Cricetus auratus
) as a Test Animal for the Diagnosis of Leptospirosis
Authors: Randall Raymond , Cooper Harold K.
Published: October 2006

There is evidence that the golden hamster (
Cricetus auratus
) is the animal of choice for the isolation of leptospirae, especially of the
Leptospira canicola
type since young guinea pigs and mice are resistant to infection and rats are entirely refractory. Both the classical strain,
L. icterohaemorrhagiae
and
L. canicola
on isolation have been found to produce a fatal infection in hamsters.

The present report deals with the isolation of
L. canicola
in two instances by the injection intraperitoneally into hamsters of urine obtained from dogs ill with suspected leptospirosis. Each of the dogs was apparently the source of infection for a human case of
Canicola leptospirosis.

The classical strain
L. icterohaemorrhagiae
was isolated from the dog for the first time in the United States. In this instance the organism was isolated by injecting both whole blood and urine from the patient intraperitoneally into young hamsters.

The injection into hamsters of suitable material from patients infected with
L. canicola
and
L. icterohaemorrhagiae
is followed by a fatal leptospirosis in the test animal.
Selection and Training of Students for Industrial Research
Authors: Hull Albert W.
Published: October 2006

To summarize, I have tried to suggest that knowledge, valuable as it is, is not considered the most important qualification for industrial research. Character, aptitude and attitudes are more important. Should they not be rated so in the college educational program? Aptitude, though it can not be trained, can and should be screened by the college more than is done to-day, to avoid the lifelong disappointments of misplacement. Character and attitudes actually are molded by college influences, for better or worse, and therefore are products of college life and are the responsibilities of the college, just as much as scholarship. The fact that the molding influence is the student body, more than the faculty, makes the problem different from that of scholarship, and a different method must be found for dealing with it. Could a method be found if sought with sufficient effort? Today we give it low priority, devoting only a small fraction of college effort to it. Why?
Oral Penicillin with Basic Aluminum Aminoacetate
Authors: Krantz John C. , Evans William E. , McAlpine James G.
Published: October 2006

This method appears to be suitable for the oral administration of penicillin. Basic aluminum aminoacetate seems admirably suited for this purpose. It is neutral and buffers gastric acidity to pH 4 to 4.5. While this work was in progress McDermott
et al.
successfully employed magnesium trisilicate in this manner.

Clinical work is now in progress using the combination in infections known to be susceptible to parenteral penicillin therapy.
A Microbiological and Fluorometric Test for Minute Amounts of Alloxan
Authors: Banerjee Sachchidananda , Dittmer Karl , du Vigneaud Vincent
Published: October 2006

A microbiological and fluorometric test for the determination of minute amounts of alloxan has been described. The test involves the conversion of the alloxan to riboflavin which is measured by microbiological or fluorometric techniques.
Penicillin in Experimental Spotted Fever
Authors: Fitzpatrick Florence K.
Published: October 2006

Guinea pigs infected with a virulent strain of spotted fever received large doses of penicillin intramuscularly every 4 hours. The injections were begun 48 hours after the onset of fever. Controls included untreated animals and others that received one dose of spotted fever rabbit immune globulin. The penicillin had no effect on the classic symptoms of this disease and all the treated animals died. (The toxicity of penicillin for guinea pigs probably was a contributing factor.) Eight out of 16 controls died; all guinea pigs receiving globulin survived. Penicillin plasma determinations led to the belief that the treatment was adequate to bring about recovery had the agent been of any value.
Isolation of
Trichomonas vaginalis
with Penicillin
Authors: Johnson Garth , Trussell Margaret , Jahn Frances
Published: October 2006

Exposure of
Trichomonas vaginalis
in vaginal discharge for 60 hours to 5,000-10,000 units of penicillin in 10.0 ml of a medium containing cysteine (0.15 per cent.), peptone, liver infusion, maltose and human serum was adequate to destroy the associated bacteria. Seven strains were isolated from seven women without a failure. This technic widens the field of investigation by offering a means of obtaining additional strains of bacteria-free
Trichomonas vaginalis
for comparative study.

Efforts to isolate
Trichomonas vaginalis
by such laborious methods as washing, micropipetting and migration have all failed to yield bacteria-free cultures at this and other laboratories. The adherence of bacteria to the trichomonads, which appear to have sticky surfaces, and the relatively slow speed with which these protozoa swim are probably in large measure responsible for failure. Further trials by these methods now seem unnecessary.

In the cases reported above the success of the penicillin method may be attributed to several factors. Resistance of
Trichomonas vaginalis
to penicillin in the concentrations reported above, the absence from the specimens of vaginal discharge of bacteria resistant to penicillin in these same concentrations, and the destruction of bacteria adherent to the sticky surfaces of the trichomonads perhaps played a large part in assuring successful isolation of the protozoa.
Immunization Against Malaria: Vaccination of Ducks with Killed Parasites Incorporated with Adjuvants
Authors: Freund Jules , Sommer Harriet E. , Walter Annabel W.
Published: October 2006

When ducks are injected with formalin-inactivated
P. lophurae
in combination with a lanolin-like substance, paraffin oil and killed tubercle bacilli, they develop considerable resistance to subsequent infection with
P. lophurae.
Oral Administration of Penicillin
Authors: Barach Alvan L. , Garthwaite Bettina , Oppenheimer Enid T. , Forman Joyce , Osburg Helen
Published: October 2006

A convenient, practical and effective procedure of administering penicillin by mouth consists of mixing the drug with one tablespoonful of aluminum hydroxide. Substantially higher blood levels are obtained following a 50,000 and a 100,000 unit dose of penicillin with this method than after administration of the drug dissolved in water, either with or without previous ingestion of a mild antacid, such as aluminum hydroxide. Adsorption of penicillin on aluminum hydroxide appears to exert a local protective effect against that portion of gastric acid with which it comes into contact.
The Free Tryptophane Content of Human Urine
Authors: Schweigert B. S. , Säuberlich H. E. , Elvehjem C. A.
Published: October 2006

The amount of l-tryptophane excreted per day by 9 different normal male subjects was determined by a microbiological method with
L. arabinosus
as the test organism. From 12-30 mg per day were excreted as contrasted to an average value of 281 mg per day reported by Albanese and Frankston. A negligible amount of indole in the urine could be demonstrated. Satisfactory values and recoveries of l-tryptophane were obtained at different levels of the test sample.
Marihuana Activity of Cannabinol
Authors: Loewe S.
Published: October 2006

Cannabinol, generally believed to be an inert component of hemp oil, is shown to have marihuana activity. The significance of this observation with regard to the relationship between structure and activity in the class of cannabinols is discussed.
Heated, Avirulent Antigens for Complement-Fixation Tests with Certain Encephalitis Viruses
Authors: Casals J.
Published: October 2006

A simple method is described for producing avirulent mouse brain antigens for complement-fixation tests in human encephalitides, by application of heat at 60°C for 30 minutes. The heated antigens retain for most of the viruses employed a sufficiently high titer to warrant their use, since they are also specific, not anticomplementary, can be lyophilized and moreover, are avirulent, and thus can be handled with safety.
Antagonism of Salicylate by Pantoyltaurine
Authors: Stansly Philip G. , Alverson Clara M.
Published: October 2006

Like pantothenic acid, pantolactone, and the pantoate ion, pantoyltaurine and other pantothenic acid analogues of this type antagonize the inhibitory effect of salicylate on
E. coli.

It is suggested that the active antagonist in a solution of such an analogue is pantolactone or pantoate. These (particularly the former) could conceivably be contaminants of the analogues. However, the liberation of pantoate by hydrolysis, appears to be a more likely explanation for the antisalicylate effect.

The presence of pantolactone or pantoate in a solution of pantoyltaurine and similar analogues of pantothenic acid provides a possible explanation for the ineffectiveness of these drugs in inhibiting the growth of microorganisms which can utilize pantolactone or pantoate for the synthesis of pantothenic acid.
The Activity of Synthetic Folic Acid in Purified Rations for the Chick
Authors: Luckey T. D. , Moore P. R. , Elvehjem C. A. , Hart E. B.
Published: October 2006

The addition of 25γ of synthetic folic acid per 100 grams of our basal ration prevents the reduced growth, poor feathering condition, and low hemoglobin and hematocrit values consistently obtained when the basal ration is fed to chicks. More than 25γ are needed when the diet contains sulfasuxidine. Evidence for the possible indirect action of folic acid is summarized.

Vitamin C or whole liver powder gives a slight response in the presence of adequate amounts of synthetic folic acid.
Elemental Analysis of Biological Specimens in Air with a Proton Microprobe
Authors: Horowitz Paul , Aronson Michael , Grodzins Lee , Ladd William , Ryan Jean , Merriam George , Lechene Claude
Published: October 2006

The unique capabilities of the proton microprobe in an atmospheric environment as a biological tool are illustrated in studies of arsenic and mercury distributions in single strands of hair from poisoning victims and of the distributions of several abundant elements in frozen hydrated eye and kidney specimens from rats.
Mechanism of Spontaneous Cure in Puberty of Ringworm of the Scalp
Authors: Rothman Stephen , Smiljanic Adelaide M. , Weitkamp Alfred W.
Published: October 2006

With onset of puberty, the sebaceous glands of the scalp start to secrete a sebum which contains, in higher concentration than before, lowboiling saturated fatty acids with selective fungistatic and fungicidal action on
M. audouini.
Highly active normal aliphatic monobasic acids having odd numbers of carbon atoms, including pelargonic acid, have been isolated from hair fat of adults. The "adult type" of hair fat does not kill the fungus spores within the hair but prevents infection of the new hair following the old infected hair in the process of shedding.

Detailed reports are to be published elsewhere.
A Method for Immunological and Chemical Investigations of Body Fluids by Means of Purified Gelatin
Authors: Kanner Oscar
Published: October 2006

A method is presented whereby certain constituents of serum or other liquids may be concentrated by the swelling of undissolved gelatin. Applications to chemistry, to the study of antibodies, and to the serology of syphilis have been indicated.

Colloids, such as proteins and cholesterol, were found to be concentrated as expected. Chlorides also complied with expectation, fully entering the swelling gelatin. An anomaly was found with calcium in blood serum; all of it behaved like nondiffusible material, in contrast with known facts pertaining to dialysis and ultrafiltration.
Blood Sugar Level Following Intravenous Glucose in Rheumatoid Arthritis
Authors: Flynn Joseph E. , Irish Oliver J.
Published: October 2006

Since the majority of patients with rheumatoid arthritis show a slower fall in the blood sugar level after the intravenous injection of glucose than do the normal controls, the alteration cannot be explained on the basis of gastrointestinal dysfunction.

Differences in the renal threshold of glucose do not explain the altered glucose tolerance, since approximately the same amount of glucose is lost in the urine in both groups.

Blood samples taken at 3 and 5 minutes following the injection of the glucose showed the height of the blood sugar level to be approximately the same in the patients with rheumatoid arthritis and in normals. The slower fall in the blood sugar level of the former is therefore not a simple function of a greater rise following the intravenous administration of the glucose.

Although the patients with severe poliomyelitis had as much or more atrophy than the rheumatoid arthritic patients, there was no delay in rate of fall of the blood sugar level after the intravenous administration of glucose.

In view of the fact that the hepatic homeostatic control regulates the blood sugar level, faulty utilization of glucose by extrahepatic tissues cannot be considered the primary factor responsible for the alteration of the glucose tolerance.

The altered glucose tolerance in rheumatoid arthritis is explainable on the basis of an altered threshold of the hepatic homeostatic control of the blood sugar. Additional studies must be done to determine whether this derangement emanates directly from extrahepatic influences.
Inactivation of Penicillins G and K by Liver and Kidney
Authors: Tepperman Jay , Rakieten N. , Valley G. , Lyon Edna W.
Published: October 2006

The inactivation of penicillin K is more rapid in the renal-ligated rabbit than in the renal-ligated, eviscerate preparation. Inactivation of penicillin K occurs in the presence of surviving liver and kidney slices. Small amounts of penicillin G were inactivated by liver slices; larger amounts disappeared in the presence of kidney slices. The inactivation of penicillin K in the presence of rabbit liver and kidney slices is demonstrable anaerobically as well as aerobically.
New Concept of Competitive Inhibition of the Renal Tubular Excretion of Penicillin
Authors: Beyer Karl H.
Published: October 2006

It has been found that the excretion of penicillin by a renal tubular transport mechanism could be physiologically inhibited reversibly. The basis for this effect is thought to be one of substrate competition between penicillin, which is excreted by the tubules, and 4′-carboxyphenylmethanesulfonanilide, which is essentially refractory to excretion by that transport mechanism.
Mitogen-Induced Blastogenic Responses of Lymphocytes from Marihuana Smokers
Authors: White Steven C. , Brin Steven C. , Janicki Bernard W.
Published: October 2006

Blastogenic responses in vitro to phytohemagglutinin and pokeweed mitogen were examined in microcultures of peripheral blood lymphocytes from a group of 12 healthy, long-term marihuana smokers and a group of matched control subjects. With either mitogen, no significant difference in cellular incorporation of [
3
H]thymidine was noted between the groups. These results were interpreted to indicate that the functional status of blood lymphocytes was not altered by long-term smoking of marihuana.
Blockade of Ovulation in Rats by Inhibitory Analogs of Luteinizing Hormone-Releasing Hormone
Authors: de la Cruz Antonio , Coy David H. , Vilchez-Martinez Jesus A. , Arimura Akira , Schelly Andrew V.
Published: October 2006

An antagonist of luteinizing hormone-releasing hormone (LH-RH). [D- Phe
2
- Phe
3
-D- Phe
6
]-LH-RH (Phe, phenylalanine), suppressed luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release in male rats in response to LH-RH for at least 4 hours. Three subcutaneous injections of 1 milligram of this antagonist into rats during proestrus completely suppressed ovulation, while a single injection of 1.5 milligrams per rat inhibited 95.3 percent of the preovulatory surge of LH, 84.2 percent of the FSH surge, and suppressed ovulation by 86.4 percent.
Sex Pheromone of the Oak Leaf Roller: A Complex Chemical Messenger System Identified by Mass Fragmentography
Authors: Hendry L. B. , Anderson M. E. , Jugovich J. , Mumma R. O. , Robacker D. , Kosarych Z.
Published: October 2006

The sex pheromone of the oak leaf roller,
Archips semiferanus
Walker, is composed of a complex mixture of chemical signals. The attractant component of the pheromone contains a series of tetradecenyl acetates having double bonds in positions 2 to 12. Mass fragmentography of the ozonolysis products of the attractant component was used to locate the double bonds in the various isomer.
Learning: Rapid Aversive Conditioning in the Gastropod Mollusk
Pleurobranchaea
Authors: Mpitsos George J. , Collins Stephen D.
Published: October 2006

Untrained
Pleurobranchaea
feed voraciously when presented food and withdraw from electrical shocks. We trained experimental animals in ten trials spaced 1 hour apart to withdraw from food alone by electrically shocking them if they fed or were indifferent to food. The greatest increase in the number of learned withdrawal responses occurred within 12 hours after conditioning, and was accompanied by long-lasting increases in the threshold and latency of feeding responses. Control animals, which received food and shock alternately (unpaired) every half hour, showed considerably weaker changes than experimentals. These control responses quickly returned to initial levels after conditioning.
Neural Plasticity in Visual Cortex of Adult Cats After Exposure to Visual Patterns
Authors: Creutzfeldt O. D. , Heggelund P.
Published: October 2006

Over a period of 2 weeks, adult cats were twice a day exposed for 1 hour to a visual environment consisting only of vertical stripes and for the rest of the time were kept in darkness. Subsequent investigation of the striate cortex showed a decrease in the number of neurons sensitive to orientations around the vertical relative to those sensitive to horizontal orientations. This indicates that plasticity of functional properties of the cortical neuronal network still exists in adult animals.
Leukocyte Recruitment to Airways by Cigarette Smoke and Particle Phase in Contrast to Cytotoxicity of Vapor
Authors: Kilburn Kaye H. , McKenzie Wayland
Published: October 2006

After hamsters had breathed fresh cigarette smoke in a miniature chamber, airways of the lung showed recruitment of polymorphonuclear leukocytes. Exposure to particles alone by removal of the vapor phase with charcoal did not change the leukocyte response. However, exposure to cigarette smoke vapor after removal of particles with Cambridge filters did not recruit leukocytes but produced nuclear and cytoplasmic vacuoles, double nuclei, and exfoliation of cells.