bluuebunny/crossref_metadata_2025 huggingface dataset:
Thiamine Triphosphatase in the Membranes of the Main Electric Organ of Electrophorus electricus: Substrate‐Enzyme Interactions
Authors: Bettendorff Lucien , Grandfils Christian , Wins Pierre , Schoffeniels Ernest
Published: October 2006

The main eJectric organ of Electrophorus electricus is particularly rich in thiamine triphosphate (TTP). Membrane fractions prepared from this tissue contain a thiamine triphosphatase that is strongly activated by anions and irreversibly inhibited by 4,4′‐diisothiocyanostilbene‐2.2′‐disul‐fonic acid (DIDS), an anion transport inhibitor. Kinetic parameters of the enzyme are markedly affected by the conditions of enzyme preparation: In crude membranes, the apparent Km is 1.8 mM and the pH optimium is 6.8, but trypsin treatment of these membranes or their purification on a sucrose gradient decreases both the apparent Am (to 0.2 mM) and the pH optimum (to 5.0). Anions such as NO3 (250 mM) have the opposite effect, i.e., even in purified membranes, the pH optimum is now 7.8 and the Km is 1.1 mM; at pH 7.8, NO3 increases the Vmax 24‐fold. TTP protects against inhibition by DIDS, and the KD for TTP could be estimated to be 0.25 mM, a value close to the apparent Km measured in the same purified membrane preparation. Thiamine pyrophosphate (0.1 mM) did not protect against DIDS inhibition. At lower (10‐5‐10‐6M) substrate concentrations. Lineweaver‐Burk plots of thiamine triphosphatase activity markedly deviate from linearity, with the curve being concave downward. This suggests either anticooperative binding or the existence of binding sites with different affinities for TTP. The latter possibility is supported by binding data obtained using [γ‐32P]TTP. Our data suggest the existence of a high‐affinity binding site (KD of ˜0.5 μM) for the Mg‐TTP complex. The membrane‐bound thiamine triphosphatase is insensitive to low concentrations of vanadate and is not activated by protonophores. These and other features suggest that this enzyme is quite distinct from most of the known membrane ATPases and that it may have a specific function in excitable cell membranes, possibly in relation to their permeability to certain anions.
Postnatal Development of Cholecystokinin‐Like Immunoreactivity and Its mRNA Level in Rat Brain Regions
Authors: Takeda Katsumichi , Koshimoto Hiroyuki , Uchiumi Fumiaki , Haun Randy S. , Dixon Jack E. , Kato Takeshi
Published: October 2006

Developmental changes of preprocholecystokinin mRNA (CCK mRNA) and cholecystokinin‐like immunoreactivity (CCK‐LI) were examined in rat brain regions (frontal cortex, colliculi, hippocampus, striatum, and cerebellum) using RNA dot blot assays with cholecystokinin (CCK) cDNA and radioimmunoassay, respectively. The CCK‐LI levels in all regions examined were Very low at birth. Excluding the cerebellum, the levels in these Regions increased postnatally and reached adult values at 28 days of age. In contrast to CCK‐LI, CCK mRNA levels changed dramatically during development. A considerable amount of CCK mRNA was detected in the frontal cortex and hippocampus at birth. The changes in the level of CCK mRNA in the frontal cortex and colliculi paralleled those of CCK‐LI, including a rapid increase from 7 to 14 days of age. The synthesis of CCK mRNA preceded the appearance of CCK‐LI. CCK mRNA levels in the hippocampus and striatum exhibited a transient increase, with a peak at 14 days of age. In the adult brain, the CCK mRNA levels were high in the frontal cortex, moderate in the hippocampus and colliculi, and low in the striatum. The cerebellum contained only a negligible amount of CCK mRNA during development. The relatively high level of CCK‐LI compared with the low level of CCK mRNA in the striatum supports the idea that most of the striatal CCK‐LI is supplied from extrastriatal regions. These results suggest that (a) CCK gene expression, numbers of CCK neurons, or both may increase from 7 to 14 days of age and (b) differential regulation of CCK gene expression and posttranscriptional regulatory mechanisms may exist in the various brain regions during development.
Changes in Polyamine Concentrations in Amygdaloid‐Kindled Rats
Authors: Hayashi Yasushi , Hattori Yukio , Moriwaki Akiyoshi , Saeki Kiyomi , Hori Yasuo
Published: October 2006

Concentrations of the polyamines putrescine, spermidine, and spermine were investigated in the left and right amygdala and in the remaining cerebrum, in which kindling was induced by repeated application of electrical stimulation of the left amygdala of rats. In kindled rats, the concentrations of spermidine and spermine increased slightly, but elevations did not reach significant levels in any brain regions. The most profound increase was detected in the putrescine concentration in all parts of the cerebrum 1–8 h after the final stimulation. These results suggest that the increases in concentrations of polyamines, particularly of putrescine, are involved in the pathogenesis of amygdaloid kindling.
Effect of Desipramine on a Glycoprotein Sialyltransferase Activity in C6 Cultured Glioma Cells
Authors: Broquet Pierre , Baubichon‐Cortay Hélèna , George Pascal , Peschard Marie‐Jo , Louisot Pierre
Published: October 2006

The tricyclic antidepressant desipramine, when added to culture medium, gave rise in C6 rat glioma cells to a decrease of the activity of the enzyme asialofetuin sialyltransferase. The inhibition was dose and time dependent and was observed in both multiplying cells and cells blocked with 2 mM thymidine or depletion of amino acids. This inhibition was rather specific to the sialyltransferase, as under the conditions where this enzyme was inhibited up to 70%, other enzymes such as dolichol phosphate mannose synthetase, glutamine synthetase, and glycerol phosphate dehydrogenase remained unaffected. This inhibition was not reversed after removal of desipramine from the medium and was not observed by direct addition of desipramine to the sialyltransferase incubation assay. Under the same conditions, W‐7 [N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide], which is known to be a potent calmodulin antagonist and an inhibitor of calmodulin‐dependent kinases, gave the same concentration‐dependent inhibition profile of sialyltransferase as desipramine, whereas H‐7 [1‐(5‐isoquinolinylsulfonyl)‐2‐methylpiperazine], which is an inhibitor of protein kinase C and cyclic nucleotide‐dependent kinases, had no effect. So, it is suggested that desipramine inhibits the sialyltransferase activity in C6 glioma cells through a calmodulin‐dependent system.
Vesicular and Ganglionic Norepinephrine in the Rat: Progressive Increase with Age
Authors: Buu Nguyen T. , Debinski Waldemar
Published: October 2006

This study analyzed dopamine (DA) and norepinephrine (NE) in the synaptic vesicles and cytoplasm of brains of rats of 2 months and 14 months. The data revealed a clear NE increase in the synaptic vesicles of the 14‐month‐old rats, contrasting with NE in the cytoplasmic fraction of the rat brain, which remained unchanged with age. Synaptic vesicles from different regions of rat brain, including those from the striatum, consistently exhibited higher NE than DA concentrations, suggesting that they are predominantly noradrenergic. In the brain, DA concentrations in vesicular and cytoplasmic fractions did not vary with age, whereas in the superior cervical ganglia DA and NE concentrations increased in the older rats. L‐3,4‐Dihydroxyphenylalanine administration significantly increased DA without affecting NE in the ganglia of rats of all ages. In the brain, such a treatment significantly raised DA only in the synaptic vesicles of the older rats, suggesting an increased facilitation of DA transport into the synaptic vesicles with age, which may account for the higher vesicular NE in the older rats.
Survival of Chick Embryonic Sensory Neurons in Culture Is Supported by Phorbol Esters
Authors: Bhave Sanjiv V. , Malhotra Ravindra K. , Wakade Taruna D. , Wakade Arun R.
Published: October 2006

Sensory neurons of the chick embryo are supported in culture by several neurotrophic factors, including the phorbol esters. Because phorbol esters are known to activate one of the second messengers, namely, protein kinase C, it was of interest to see if the neurotrophic action of phorbol 12,13‐dibutyrate (PDB) was related to the activation of protein kinase C in sensory neurons. Sensory neurons were obtained from dorsal root ganglia of 10‐day‐old chick embryos and maintained in a serum‐free medium for several days to quantify survival and analyze protein kinase C activity. PDB (30 nM) supported the survival of ± 50% of the total number of neurons plated. This value was comparable to that supported by nerve growth factor (NGF; 40 ng/ml). If PDB and NGF were added together, there was no additive effect on the survival. The protein kinase C activity of the particulate and cytosolic fractions of sensory neurons supported by NGF for 3 days was 1.26 ± 0.1 and 2.9 ± 0.32 pmol/min/mg of protein, respectively. In contrast, neurons supported by PDB showed an ± 500% increase in enzyme activity in their particulate fraction. The enzyme activity of the cytosolic fraction was decreased by ± 40%. If NGF‐supported neurons were treated with PDB (30 nM) for 15 min, protein kinase C activity increased > 400% in the particulate fraction, whereas an ± 50% decrease was observed in the cytosolic fraction. The protein kinase C value, expressed as a ratio of the activities in the particulate to cytosol fractions, showed large increases after phorbol treatment. The ratio was 0.43 in NGF‐supported neurons and increased to 3.57 in PDB‐supported neurons. NGF‐supported neurons treated with PDB for 15 min had a ratio of 4.1. Phorbol‐13‐acetate did not support the survival, nor did it increase protein kinase C activities in NGF‐supported neurons. Because sensory neurons contain substantial amounts of choline acetyltransferase (ChAT) activity, we compared ChAT activity in NGF‐ and PDB‐supported sensory neurons. Values were 21.93 ± 3.7 and 22.09 ± 4.6 pmol of acetylcholine formed/min/mg of protein, respectively. These results suggest that neurotrophic action of PDB on chick sensory neurons is probably mediated through protein kinase C. The present data also suggest that NGF and PDB act on the same subpopulation of sensory neurons of the dorsal root ganglia of the chick to support their survival in culture.
Estimation of Free Dopamine in the Cytoplasm of the Giant Dopamine Cell of Planorbis corneus by Voltammetry and Capillary Electrophoresis
Authors: Chien Jennifer B. , Wallingford Ross A. , Ewing Andrew G.
Published: October 2006

Voltammetric electrodes having a tip diameter of 2–12 μ and microscale capillary zone electrophoresis have been used for dynamic and static monitoring of dopamine in the somal cytoplasm of the giant dopamine neuron of Planorbis corneus. Intracellular dopamine levels can be altered by extracellular application of dopamine or ethanol. The latter experiment provides a means to estimate total stores of endogenous dopamine, and the evidence presented suggests that at least 98% of these stores are bound and not directly accessible to the cytoplasm.
Autoradiographic Characterization and Localization of Quisqualate Binding Sites in Rat Brain Using the Antagonist [3H]6‐Cyano‐7‐Nitroquinoxaline‐2,3‐Dione: Comparison with (R,S)‐[3H]α‐Amino‐3‐Hydroxy‐5‐Methyl‐4‐Isoxazolepropionic Acid Binding Sites
Authors: Nielsen Elsebet Ø. , Drejer Jørgen , Cha Jang‐Ho J. , Young Anne B. , Honoré Tage
Published: October 2006

Using quantitative autoradiography, we have investigated the binding sites for the potent competitive non‐N‐methyl‐D‐aspartate (non‐NMDA) glutamate receptor antagonist [3H]6‐cyano‐7‐nitro‐quinoxaline‐2,3‐dione ([3H]‐CNQX) in rat brain sections. [3H]CNQX binding was regionally distributed, with the highest levels of binding present in hippocampus in the stratum radiatum of CA1, stratum lucidum of CA3, and molecular layer of dentate gyrus. Scatchard analysis of [3H]CNQX binding in the cerebellar molecular layer revealed an apparent single binding site with a KD= 67 ± 9.0 nM and Bmax= 3.56 ± 0.34 pmol/mg protein. In displacement studies, quisqualate, L‐glutamate, and kainate also appeared to bind to a single class of sites. However, (R,S)‐α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) displacement of [3H]CNQX binding revealed two binding sites in the cerebellar molecular layer. Binding of [3H]AMPA to quisqualate receptors in the presence of potassium thiocyanate produced curvilinear Scatchard plots. The curves could be resolved into two binding sites with KD1= 9.0 ± 3.5 nM, Bmax= 0.15 ± 0.05 pmol/mg protein, KD2= 278 ± 50 nM, and Bmax= 1.54 ± 0.20 pmol/mg protein. The heterogeneous anatomical distribution of [3H]CNQX binding sites correlated to the binding of L‐[3H]glutamate to quisqualate receptors and to sites labeled with [3H]AMPA. These results suggest that the non‐NMDA glutamate receptor antagonist [3H]CNQX binds with equal affinity to two states of quisqualate receptors which have different affinities for the agonist [3H]AMPA.
Calmodulin‐Binding Proteins and Calcium/Calmodulin Regulated Enzyme Activities Associated with Brain Actomyosin
Authors: Larson Roy E. , Espindola Foued S. , Espreafico Enilza M.
Published: October 2006

Calcium‐ and calmodulin‐regulated ATPase and protein kinase activities are shown to be strongly associated with brain actomyosin. Similar enzymatic activities and an invariable polypeptide profile on sodium dodecyl sulfatepolyacrylamide gel electrophoresis were obtained for brain actomyosin taken through a solubilization‐precipitation cycle (1.0–0.1 M KC1), or precipitated from buffers containing 1% Triton X‐100 or 10 mM EDTA and 10 mM EGTA. These data suggest a specific complex of brain actomyosin with a protein kinase similar to calmodulin‐dependent kinase II, a 190‐kDa calmodulin‐binding protein (P190), and a calmodulin‐like polypeptide. P190 was the major substrate for endogenous calcium‐dependent phosphorylation. 125I‐Calmodulin overlay technique revealed four major calmodulin‐binding polypeptides associated with brain actomyosin: 50‐and 60‐kDa subunits of the calmodulin‐dependent kinase II, P190, and a high molecular weight polypeptide which is probably fodrin. A fraction enriched in P190 had Ca2+‐ and calmodulin‐stimulated MgATPase activity, but not myosin‐like K‐EDTA ATPase activity. The lack of immunological crossreactivity between brain myosin heavy chain and P190 confirmed that they are distinct molecules.
Formation of [Leu5]Enkephalin from Dynorphin A(1–8) by Rat Central Nervous Tissue In Vitro
Authors: Dixon D. M. , Traynor J. R.
Published: October 2006

[3H]Dynorphin A(1–8) is readily metabolised by rat lumbosacral spinal cord tissue in vitro, affording a variety of products including a significant amount (20% recovered activity) of [3H][Leu5]enkephalin. In the presence of the peptidase inhibitors bestatin, captopril, thiorphan, and leucylleucine, [3H][Leu5]enkephalin was the major metabolic product, accounting for 60% of recovered activity. Production of [3H][Leu5]enkephalin was seen across all gross brain regions. The enzyme responsible for the cleavage has an optimal substrate length of 8–13 amino acids and is inhibited b N‐[1‐(RS)‐carboxy‐2‐phenylethyl]‐Ala‐Ala‐Phe‐p‐aminobenzoate, a site‐directed inhibitor of the metalloendopeptidase EC 3.4.24.15. However the enzymic breakdown also has properties in common with involvement of endo‐oligopeptidase A. Possible consequences of the formation of [Leu5]enkephalin from the smaller dynorphins are discussed.
Acetylcholine Synthesis and Release in the Extensor Digitorum Longus Muscle of Mature and Aged Rats
Authors: Smith Dean O.
Published: October 2006

Uptake of labeled choline and its incorporation into acetylcholine (ACh) were assayed at the neuromuscular junction of the extensor digitorum longus (EDL) muscle of rats aged 11 (mature adult) and 27 (aged) months. Under resting conditions, there were no significant differences in muscle ACh or choline levels. Following a 1‐h incubation in labeled choline, however, tissue from the younger rats contained significantly greater amounts of labeled choline and labeled ACh; the specific activities of ACh and choline were nearly 10‐fold higher in the 11‐month‐old animals, indicating reduced uptake of labeled choline in the older animals. ACh and choline efflux rates under resting conditions did not change with age, indicating an uncoupling of exogenous choline uptake and ACh efflux in EDL during aging. During nerve stimulation (1 Hz), the amount of labeled choline incorporated into ACh was 150% greater in the aged animals. The specific activity of ACh released during stimulation was correspondingly greater in the 27‐month‐old animals, although total ACh released did not change appreciably with age. There were no age‐related differences in choline acetyltransferase activity. Contrasting results were obtained from diaphragm in previous studies; the linkage between choline uptake and ACh efflux was maintained during rest and stimulation in the diaphragm. Hypothetically, these differences between EDL and diaphragm may be related to their diverse activation patterns: EDL is recruited much less frequently and less regularly than diaphragm, a continually active vital muscle.
Effects of Different Semipermeable Membranes on In Vitro and In Vivo Performance of Microdialysis Probes
Authors: Hsiao John K. , Ball Beth Ann , Morrison Paul F. , Mefford Ivan N. , Bungay Peter M.
Published: October 2006

The in vitro and in vivo performance of three different semipermeable microdialysis membranes was compared: a proprietary polycarbonate‐ether membrane made by Carnegie Medecin; cuprophan, a regenerated cellulose membrane; and polyacrylonitrile. When microdialysis probes were tested in a stirred in vitro solution, large and statistically significant differences among the three membranes in extraction of acid metabolites (3,4‐dihydroxyphenylacetic acid, 5‐hydroxyindoleacetic acid, and homovanillic acid) and acetaminophen were found. Polyacrylonitrile had the highest extractions in vitro. In contrast, when microdialysis probes were implanted in vivo (in rat striatum), extraction of acid metabolites and acetaminophen did not differ significantly among the different membranes. These results are consistent with predictions made by a mathematical model of microdialysis and can be explained by the fact that in vitro the main factor limiting extraction is membrane resistance to diffusion, whereas tissue resistance to diffusion plays a more dominant role in vivo. These findings suggest that (aside from differences in surface area), the choice of semipermeable membrane will generally have little effect on in vivo microdialysis results. Furthermore, in vitro measurements of microdialysis probe extractions are not a reliable way of calibrating in vivo performance.
Expression of stem cell factor and its receptor, c‐kit, in human oral mesenchymal cells
Authors: Gagari Eleni , Rand Matthew K. , Tayari Lili , Vastardis Heleni , Sharma Parul , Hauschka Peter V. , Damoulis Petros D.
Published: October 2006

Stem cell factor (SCF) is the pleiotropic ligand for the tyrosine kinase receptor, c‐kit. Ligand and receptor are usually expressed in different cell types, and binding of SCF to c‐kit promotes cell proliferation, differentiation, and recruitment of progenitor cells in various biologic systems. However, the localization of these two molecules in cells of the oral cavity has not been systematically examined. We investigated the expression of SCF and c‐kit in human dental pulp (HDP) cells as well as in human gingival fibroblasts (HGF). Both alternatively spliced isoforms of SCF were detected (through reverse transcription–polymerase chain reaction) in RNA obtained from the two cell types. Western analysis established that both cell types express SCF and/or c‐kit, whereas flow cytometry demonstrated distinct cell populations expressing only the ligand (SCF), only the receptor (c‐kit), or co‐expressing the two. HDP cultures showed higher soluble SCF (sSCF) production associated with faster cell growth, as compared with HGF cultures. In both cell types, however, sSCF levels appeared to increase as a result of in vitro aging and/or differentiation.
Three‐dimensional finite‐element model of the human temporomandibular joint disc during prolonged clenching
Authors: Hirose Miho , Tanaka Eiji , Tanaka Masao , Fujita Reiji , Kuroda Yukiko , Yamano Eizo , Van Eijden Theo M. G. J. , Tanne Kazuo
Published: October 2006

In the temporomandibular joint (TMJ), overloading induced by prolonged clenching appears to be important in the cascade of events leading to disc displacement. In this study, the effect of disc displacement on joint stresses during prolonged clenching was studied. For this purpose, finite‐element models of the TMJ, with and without disc displacement, were used. Muscle forces were used as a loading condition for stress analysis during a time‐period of 10 min. The TMJ disc and connective tissue were characterized as a linear viscoelastic material. In the asymptomatic model, large stresses were found in the central and lateral part of the disc through clenching. In the retrodiscal tissue, stress relaxation occurred during the first 2 min of clenching. In the symptomatic model, large stresses were observed in the posterior part of the disc and in the retrodiscal tissue, and the stress level was kept constant through clenching. This indicates that during prolonged clenching the disc functions well in the asymptomatic joint, meanwhile the retrodiscal tissue in the symptomatic joint is subject to excessive stress. As this structure is less suitable for bearing large stresses, tissue damage may occur. In addition, storage of excessive strain energy might lead to breakage of the tissue.
Oral health, dental anxiety, and behavior management problems in children with attention deficit hyperactivity disorder
Authors: Blomqvist My , Holmberg Kirsten , Fernell Elisabeth , Ek Ulla , Dahllöf Göran
Published: October 2006

Attention deficit hyperactivity disorder (ADHD) is a common developmental disorder. The aim of this study was to investigate whether children with ADHD have a higher caries prevalence, a higher degree of dental anxiety, or more dental behavior management problems (BMP) than children of a control group. Twenty‐five children with ADHD and a control group of 58 children, all aged 11 yr, were included in the study. The children underwent a clinical dental examination, and bitewing radiographs were taken. The parents completed the Dental Subscale of Children's Fear Survey Schedule (CFSS‐DS). Dental records from the subjects were obtained, and data regarding notes on behavior management problems (BMP) of the children when between 3 and 10 yr of age were compiled. Compared with controls, children with ADHD had significantly higher decayed, missing or filled surfaces (DMFS) (2.0 ± 3.0 vs. 1.0 ± 1.5) and significantly higher decayed surfaces (DS) (1.7 ± 3.6 vs. 0.5 ± 0.9). Differences between the groups regarding CFSS‐DS scores were non‐significant. In the ADHD group, the prevalence of BMP increased when the children were between 7 and 9 yr of age. In conclusion, children with ADHD exhibited a higher caries prevalence, did not exhibit a higher degree of dental anxiety, and had more BMP than children of a control group.
Runx2 and dental development
Authors: Camilleri Simon , McDonald Fraser
Published: October 2006

The Runx2 gene is a master transcription factor of bone and plays a role in all stages of bone formation. It is essential for the initial commitment of mesenchymal cells to the osteoblastic lineage and also controls the proliferation, differentiation, and maintenance of these cells. Control is complex, with involvement of a multitude of factors, thereby regulating the expression and activity of this gene both temporally and spatially. The use of multiple promoters and alternative splicing of exons further extends its diversity of actions. RUNX2 is also essential for the later stages of tooth formation, is intimately involved in the development of calcified tooth tissue, and exerts an influence on proliferation of the dental lamina. Furthermore, RUNX2 regulates the alveolar remodelling process essential for tooth eruption and may play a role in the maintenance of the periodontal ligament. In this article, the structure of Runx2 is described. The control and function of the gene and its product are discussed, with special reference to developing tooth tissues, in an attempt to elucidate the role of this gene in the development of the teeth and supporting structures.
Granulocytopenia and Anemia in Rats Fed Diets of Low Casein Content
Authors: Kornberg Arthur , Daft Floyd S. , Sebrell W. H.
Published: October 2006

Severe granulocytopenia and anemia were developed uniformly in rats fed protein-free diets. Casein (18 per cent) prevented these dyscrasias, but crystalline
L. casei
factor ("folic acid") did not prevent them. In the correction of granulocytopenia in rats fed protein-free diets,
L. casei
factor alone was only slightly effective, diets of higher casein content (18 or 30 per cent) were ineffective under the experimental conditions described. However,
L. casei
factor combined with an 18-per cent casein-containing diet or
L. casei
factor combined with a mixture of purified amino acids were found to be highly effective in correcting the granulocytopenia.
Choline Administration: Activation of Tyrosine Hydroxylase in Dopaminergic Neurons of Rat Brain
Authors: Ulus Ismail H. , Wurtman Richard J.
Published: October 2006

The administration of choline in doses previously shown to elevate brain acetylcholine concentrations also increases the activity of tyrosine hydroxylase in rat caudate nuclei. This response can be blocked by atropine, a muscarinic antagonist. These findings indicate that choline-induced increases in acetylcholine concentrations may be associated with parallel changes in the amount of the neurotransmitter released into synapses.
Multiple Representations of the Body Within the Primary Somatosensory Cortex of Primates
Authors: Kaas Jon H. , Nelson Randall J. , Sur Mriganka , Lin Chia-Sheng , Merzenich Michael M.
Published: October 2006

Microelectrode mapping experiments indicate that the classical primary somatosensory cortex of monkeys consists of as many as four separate body representations rather than just one. Two complete body surface representations occupy cortical fields 3b and 1. In addition, area 2 contains an orderly representation of predominantly "deep" body tissues. Area 3a may constitute a fourth representation.
Lymphocyte Surface Immunoglobulins
Authors: Marchalonis John J.
Published: October 2006

Immunoglobulins have been isolated from the surface of B (bone marrow derived) and T (thymus-derived) lymphocytes. Two types of membrane immunoglobulin occur on B lymphocytes; one type resembles the 200,000-dalton subunit of IgM, the second possesses a heavy chain electrophoretically distinct from μ chain and does not correspond to any of the known classes of mouse immunoglobulins. It might correspond to human δ chain. T lymphocytes possess only one type of surface immunoglobulin. This molecule has a mass of approximately 200,000 daltons and contains light chains and heavy chains similar to, but not identical to, μ chains. Evidence now exists that surface IgM-like immunoglobulins of B lymphocytes and T lymphocytes activated to certain antigens can bind specifically to antigen. These observations suggest that surface immunoglobulin functions as a receptor for antigen on B cells and at least on some T cells. The mechanisms by which combination of antigen with surface immunoglobulin initiate differentiation remain to be determined.
Spontaneous Regression of Friend Virus Induced Leukemia: Coinfection with Regressing and Conventional Strains of Virus
Authors: Furmanski Philip , Baldwin James , Clymer Rodney , Rich Marvin A.
Published: October 2006

Mixtures of Friend virus (CFV) and the regressing strain of Friend virus (RFV) induce leukemia which regresses. The dominance of the regressing phenotype is solely a function of a threshold dose of RFV. The minimum amount of RFV which induced regression of CFV leukemia is below the titer for induction of Friend disease, but does correlate with the titer of lymphocytic leukemia (helper) activity in these stocks.
Increased Lever Pressing for Amphetamine After Pimozide in Rats: Implications for a Dopamine Theory of Reward
Authors: Yokel Robert A. , Wise Roy A.
Published: October 2006

Low and high doses of a dopamine blocking agent had effects on lever pressing for intravenous amphetamine reward which resembled the effects of reward reduction and reward termination, respectively. Noradrenaline blockade had no such effects. A role in central mediation of reward perception is suggested for dopamine but not for noradrenaline.
Mezerein: Antileukemic Principle Isolated from
Daphne mezereum
L.
Authors: Kupchan S. Morris , Baxter Robert L.
Published: October 2006

An alcohol-water extract of
Daphne mezereum
L., a plant widely used in folk medicine for treating cancers, showed antileukemic activity against the P-388 lymphocytic leukemia in mice. Systematic fractionation of the extract has led to isolation and characterization of mezerein as the principal antileukemic component.
Vaterite: A Mineralization Product of the Hard Tissues of a Marine Organism (Ascidiacea)
Authors: Lowenstam Heinz A. , Abbott Donald P.
Published: October 2006

X-ray diffraction and infrared absorption spectra show that the spicules of the common tropical ascidian,
Herdmania momus
, are mineralized with vaterite. These are the first strictly marine organisms known to normally precipitate vaterite. The biomineralization of vaterite may constitute another link between the urochordates and vertebrates. The vaterite of ascidian spicules immersed in natural seawater remains mineralogically unchanged for 1 year, which indicates that vaterite may be preserved transiently in marine sediments.
Horizontal Cells in Cat Retina with Independent Dendritic Systems
Authors: Nelson Ralph , Lützow Astrid v. , Kolb Helga , Gouras Peter
Published: October 2006

Cat horizontal cells are retinal neurons with two functionally distinct parts: the cell body receives signals predominantly from cones, while the terminal arborization receives predominantly from rods. The long thin process connecting these parts neither generates impulses nor allows significant passive electrotonic conduction between them.
Meaning in Visual Search
Authors: Potter Mary C.
Published: October 2006

Viewers briefly glimpsed pictures presented in a sequence at rates up to eight per second. They recognized a target picture as accurately and almost as rapidly when they knew only its meaning given by a name (for example, a boat) as when they had seen the picture itself in advance.
Visual Membranes: Specificity of Fatty Acid Precursors for the Electrical Response to Illumination
Authors: Wheeler Thomas G. , Benolken R. M. , Anderson Robert E.
Published: October 2006

Rat electroretinograms were measured as a function of dietary supplements of purified ethyl esters of linolenic acid, linoleic acid, and oleic acid. Polyunsaturated fatty acids derived from precursors of linolenic and linoleic acids appear to be important functional components of photoreceptor cell membranes, although in equal dietary concentrations, linolenic acid precursors affect electroretinogram amplitudes to a greater extent than linoleic acid precursors. The electrical response of photoreceptor cell membranes appears to be a function of the position of the double bonds as well as a function of the total number of double bonds in fatty acid supplements.
Suppression of a Field Population of Houseflies with
Spalangia endius
Authors: Morgan Philip B. , Patterson R. S. , LaBrecque G. C. , Weidhaas D. E. , Benton A.
Published: October 2006

Sustained releases of the microhymenopteran pupal parasite
Spalangia endius
, at a commercial poultry installation in north Florida, completely suppressed a population of houseflies within 35 days.
Peptide Inhibition of the Prausnitz-Küstner Reaction
Authors: Hamburger Robert N.
Published: October 2006

A pentapeptide was synthesized with the same amino acid sequence that occurs in a unique region of the ε chain of immunoglobulin E near the cysteine residue participating in the linkage between the two heavy chains. This pentapeptide has the capacity to block a standard Prausnitz-Küstner reaction as well as to inhibit a known positive skin test reaction. Other similar synthetic polypeptides had less or no inhibitory activity. The likelihood that this pentapeptide amino acid sequence does in fact represent the structure of the specific immunoglobulin E binding site for the mast cell and basophil is considered.
Rapid Food-Aversion Learning by a Terrestrial Mollusk
Authors: Gelperin Alan
Published: October 2006

The terrestrial slugLimax maximuscan learn to avoid new palatable food if CO2poisoning is paired with ingestion of the new food. Some animals learn in one trial and remember without error for 3 weeks. Avoidance most commonly consists of complete rejection of the unsafe food, based on olfactory cues. This preparation offers the opportunity for detailed neurophysiological analysis of a rapid-onset learning mechanism of long duration.
Gram-Positive Bacteria: Possible Photosynthetic Ancestry
Authors: Woese C. R. , Debrunner-Vossbrinck B. A. , Oyaizu H. , Stackebrandt E. , Ludwig W.
Published: October 2006

A 16
S
ribosomal RNA gene has been sequenced from
Heliobacterium chlorum
, the recently discovered photosynthetic bacterium that contains a novel form of chlorophyll. Comparisons with other 16
S
ribosomal RNA sequences show that the organism belongs to the Gram-positive bacteria (one of ten eubacterial "phyla")—more precisely to the so-called low G + C (G, guanine; C, cytosine) subdivision thereof. This brings to five the number of such phyla that contain photosynthetic species, the other four being the purple bacteria and relatives, the green sulfur bacteria, the green nonsulfur bacteria, and the cyanobacteria. The finding suggests that Gram-positive bacteria may be of photosynthetic ancestry, and it strengthens the case for a common photosynthetic ancestry for all eubacteria.
Environmental Trends in Extinction During the Paleozoic
Authors: Sepkoski J. John
Published: October 2006

Extinction intensities calculated from 505 Paleozoic marine assemblages divided among six environmental zones and 40 stratigraphic intervals indicate that whole communities exhibit increasing extinction offshore but that genera within individual taxonomic classes tend to have their highest extinction onshore. The offshore trend at the community level results from a concentration of genera in classes with low characteristic extinction rates in nearshore environments. This finding is consistent with the ecologic expectation that organisms inhabiting unpredictably fluctuating environments should suffer more extinction than counterparts living under more predictably equitable conditions.
Diode-Laser Absorption Spectroscopy of Supersonic Carbon Cluster Beams: the ν
3
Spectrum of C
5
Authors: Heath J. R. , Cooksy A. L. , Gruebele M. H. , Schmuttenmaer C. A. , Saykally R. J.
Published: October 2006

A new spectroscopic experiment has been developed in which rovibrational transitions of supersonically cooled carbon clusters, which were produced by laser vaporization of graphite, have been measured by direct-absorption diode-laser spectroscopy. Thirty-six sequential rovibrational lines of the ν
3
band of the C
5
carbon cluster have been measured with Doppler-limited resolution. The absorption spectrum is characteristic of a linear molecule with a center of symmetry. Least-squares analysis of the spectrum indicates an effective carbon-carbon bond length of 1.283 angstroms, in good agreement with ab initio quantum chemical calculations. This work confirms the detection of C
5
in IRC + 10216 reported in the accompanying paper.
Oxygen Supersaturation in Ice-Covered Antarctic Lakes: Biological Versus Physical Contributions
Authors: Craig H. , Wharton R. A. , McKay C. P.
Published: October 2006

Freezing in ice-covered lakes causes dissolved gases to become supersaturated while at the same time removing gases trapped in the ablating ice cover. Analysis of N
2
, O
2
, and Ar in bubbles from Lake Hoare ice shows that, while O
2
is ∼2.4 times supersaturated in the water below the ice, only 11% of the O
2
input to this lake is due to biological activity: 89% of the O
2
is derived from meltwater inflow. Trapped bubbles in a subliming ice cover provide a natural "fluxmeter" for gas exchange: in Lake Hoare as much as 70% of the total gas loss may occur by advection through the ice cover, including ∼75% of the N
2
, ∼59% of the O
2
, and ∼57% of the Ar losses. The remaining gas fractions are removed by respiration at the lower boundary (O
2
) and by molecular exchange with the atmosphere in the peripheral summer moat around the ice.
Membrane Protein Analysis by Two-Dimensional Immunoelectrophoresis
Authors: Converse Carolyn A. , Papermaster David S.
Published: October 2006

Water-insoluble membrane proteins may be analyzed by a new, rapid technique that combines electrophoresis on high-resolution sodium dodecyl sulfate (SDS) polyacrylamide gels and immunoelectrophoresis. After separation in the first dimension by electrophoresis in SDS, the proteins are subjected to a second electrophoresis at right angles through a two-layered buffered agarose gel. They first pass through a layer containing Lubrol PX which forms complexes with free SDS and then into an antiserum layer where antigen-antibody precipitates form. Precipitin arcs appear at positions corresponding to the antigens separated in the first dimension. The effectiveness of the technique was demonstrated with frog and cattle opsins, human erythrocyte membrane proteins, and their rabbit antiserums and for several water soluble proteins. By this method two fundamental parameters, molecular weight and antigenicity, may be readily used for analysis of membrane proteins.
Time-Dependent Effects of Phenothiazines on Dopamine Turnover in Psychiatric Patients
Authors: Post Robert M. , Goodwin Frederick K.
Published: October 2006

Psychiatric patients studied early during treatment with chlorpromazine and thioridazine demonstrated elevated probenecid-induced accumulations of homovanillic acid, a major dopamine metabolite, in cerebrospinal fluid. In those studied after longer periods of treatment with phenothiazines, homovanillic acid values were not elevated. This suggests that there are time-dependent effects of phenothiazines on dopamine turnover that may be relevant to the time course of antipsychotic efficacy.
Water Recycling in Lactation
Authors: Baverstock P. , Green B.
Published: October 2006

During lactation, female rodents, dingoes, and kangaroos consume urine and feces excreted by the young. Studies with tritiated water as a tracer for native water showed that roughly one-third of the water secreted as milk was returned to the mother. The results are cogent to studies of water balance of lactation and to current methods used for estimating milk production.
Concanavalin A: Its Action in Inducing Oocyte Maturation-Inducing Substance in Starfish Follicle Cells
Authors: Kubota Junko , Kanatani Haruo
Published: October 2006

Maturation of starfish oocytes is induced by 1-methyladenine produced in follicle cells under the influence of a gonad-stimulating hormonal peptide released from the nervous system. Concanavalin A stimulates isolated follicle cells to produce 1-methyladenine, which suggests that it has the same capacity as the peptide hormone to indirectly induce oocyte maturation.
Hypothalamic Hyperphagia: Dissociation from Hyperphagia Following Destruction of Noradrenergic Neurons
Authors: Ahlskog J. Eric , Randall Patrick K. , Hoebel Bartley G.
Published: October 2006

Major differences were found between classical hypothalamic hyperphagia in rats and the recently discovered hyperphagia syndrome resulting from destruction of the ventral noradrenergic bundle. Traditional medial hypothalamic lesions produced no detectable loss of norepinephrine, and the rats overate both in the daytime and at night, whereas destruction of the noradrenergic bundles with 6-hydroxydopamine depleted norepinephrine to 6 percent of normal and caused overeating only at night. Moreover, the two procedures were additive, not substitutive, in their effects on eating. These results argue against recent suggestions that destruction of the ventral noradrenergic bundle mediates the classical hyperphagia syndrome associated with localized ventromedial hypothalamic lesions. However, damage to noradrenergic pathways may contribute to the hyperphagia after extensive hypothalamic lesions.
Diversity and Adaptation in Rodent Copulatory Behavior
Authors: Dewsbury Donald A.
Published: October 2006

Copulatory patterns of muroid rodents provide an ideal locus for comparative behavioral research. Such patterns are highly stereotyped within and between the individuals of a given species, variable across species, readily elicited in the laboratory, and of great biological significance. Detailed behavioral comparisons of a broad range of muroid species have revealed extensive behavioral diversity that was not anticipated from research confined to laboratory rats. Various muroid species display postejaculatory copulations without sperm transfer, locking, thrusting, and other behavioral patterns. This behavioral diversity appears not to be the result of a simple linear pattern of evolutionary history. Rather, patterns appear to have evolved repeatedly in response to particular selective pressures acting on particular species. While understanding of the adaptive significance of these behavioral patterns remains rudimentary, important beginnings have been made.
High Speed Scintillation Autoradiography
Authors: Durie Brian G. M. , Salmon Sydney E.
Published: October 2006

Impregnation of nuclear track emulsion with liquid scintillator and exposure at -85°C allows rapid autoradiographic labeling. With tritiated thymidine of high specific activity (40 to 60 curies per millimole), exposure time can be shortened to 20 to 60 minutes, allowing complete sample processing within 4 hours. In experiments requiring isotopes with low incorporation rates or low specific activity, exposure time can be shortened from months to several days.
Alcoholic Hepatomegaly: Accumulation of Protein in the Liver
Authors: Baraona Enrique , Leo Maria A. , Borowsky Stephen A. , Lieber Charles S.
Published: October 2006

The hepatomegaly that appears after long-term feeding of ethanol results in accumulation of protein that is quantitatively as important as the increase in lipid. The bulk of protein accumulates in the soluble fraction of the cell. Hepatic albumin and transferrin concentrations increase and colchicine-binding protein decreases, thus suggesting an intrahepatic retention of export proteins.
Minor Salivary Glands as a Major Source of Secretory Immunoglobulin A in the Human Oral Cavity
Authors: Crawford John M. , Taubman Martin A. , Smith Daniel J.
Published: October 2006

Secretory immunoglobulin A is the predominant immunoglobulin in labial minor salivary gland secretions. Its mean concentration is four times higher in these secretions than in parotid gland secretion. The minor salivary glands can produce 30 to 35 percent of the immunoglobulin A that enters the oral cavity. This, together with the potential accessibility of these glands to antigenic stimulation, suggests that they may be an important source of the immune factors that are involved in the regulation of the microorganisms in the oral environment.
The Need for an Ethnomedical Science
Authors: Fabrega Horacio
Published: October 2006

Ethnomedicine is an intellectual area which embraces theoretical concerns that are relevant to both the social and biological sciences. The relation which exists between disease, social behavior, and human adaptation constitutes the primary subject matter of ethnomedicine. This relation is examined in terms of man's unique capacities for symbolization and culture. Since ethnomedical generalizations explain how social groups deal with a generic disease, they can be used to examine contemporary problems which involve the organization and practice of medicine as well as problems that stem from relations of the medical system with other subsystems in the group. Recasting contemporary social problems in this way may help to clarify their roots and sources. In focusing on fundamental properties of disease in man, ethnomedicine can also help to clarify the effects and meanings of disease and thereby make its control more rational. A theory of disease, an ultimate aim of ethnomedical inquiry, will serve as an explanatory device with wide-ranging applications.
Thermal Lens Technique: A New Method of Absorption Spectroscopy
Authors: Long M. E. , Swofford Robert L. , Albrecht A. C.
Published: October 2006

Both a single beam and a dual beam (with synchronous detection) thermal lens technique have been employed in the measurement of "colorless" organic compounds in the range 15,700 to 17,400 cm
-1
. Combination overtones of C-H stretching vibrations in benzene have been identified and agree with previous results obtained by conventional spectroscopy with a long optical path. Extinction coefficients as low as 1 × 10
-6
liter mole
-1
cm
-1
have been accurately determined. The sensitivity of the technique has been further demonstrated by measuring the S
0
→
T
1
absorption of anthracene; the spectrum compares favorably with results obtained by conventional techniques.
The Categories of Hue in Infancy
Authors: Bornstein Marc H. , Kessen William , Weiskopf Sally
Published: October 2006

Infant looking time was monitored during habituation to the repeated presentation of a wavelength stimulus selected from one basic adult hue category and after a change in stimulation. Recovery from habituation was greater to a wavelength selected from an adjacent hue category than to a wavelength from the same category even though these two stimuli were equally distant (in nanometers) from the habituation wavelength. Differential responding evidenced infants' categorical perception of hue; that is, infants see the physically continuous spectrum as divided into the hue categories of blue, green, yellow, and red. These results help to resolve the long-standing controversy surrounding the primacy of perception over language in the organization of hue.
Messenger RNA Induction of Fast Sodium Ion Channels in Cultured Cardiac Myoblasts
Authors: McLean Michael J. , Renaud Jean-Francois , Sperelakis Nick , Niu Mann Chiang
Published: October 2006

Incubation with adult heart messenger RNA caused the appearance of fast sodium ion channels in young myocardial cells whose development had been arrested in vitro. The induction was blocked by cycloheximide, indicating dependence on protein synthesis. Thus, cardiac myoblasts can be made to differentiate in vitro, and membrane properties can be altered by exogenous RNA.
Similarity of Albomycin and Grisein
Authors: Stapley Edward O. , Ormond Robert E.
Published: October 2006

Albomycin and grisein were found to be composed of four antibiotically active substances of which A, a strongly active component, and D, a very weakly active component, appear to be stable to purification, while C has been observed to break down continually with concomitant appearance of more A. On the basis of published reports and of studies made in our laboratories, it is concluded that albomycin and grisein are chemically very similar and identical with respect to antimicrobial activity.
Surface Predominance of Trace Elements in Airborne Particles
Authors: Linton R. W. , Loh A. , Natusch D. F. S. , Evans C. A. , Williams P.
Published: October 2006

A number of minor and trace elements including Be, C, Ca, Cr, K, Li, Mn, Na, P, Pb, S, Tl, V, and Zn present in coal fly ash are found to be preferentially concentrated on the particle surfaces. Environmentally effective concentrations of these elements are thus much higher than indicated by conventional bulk analyses.