bluuebunny/crossref_metadata_2025 huggingface dataset:
Platelet-Mediated Cholesterol Accumulation in Cultured Aortic Smooth Muscle Cells
Authors: Kruth Howard S.
Published: October 2006

Cholesterol accumulates within smooth muscle cells and macrophages in atherosclerotic lesions, thereby contributing to the progressive enlargement of these lesions. The mechanism of this cellular accumulation of cholesterol is not known. The possibility that platelets may have a role in the cellular cholesterol accumulation that occurs during atherogenesis was investigated. Incubation of thrombin-activated washed rat platelets (or platelet-free supernatants prepared from thrombin-activated platelets) with cultured rat aortic smooth muscle cells induced cholesteryl ester lipid droplet accumulation within the smooth muscle cells. No cholesteryl ester lipid droplets accumulated when smooth muscle cells were incubated with unactivated platelets. Smooth muscle cell lipid droplet accumulation occurred in the absence of serum lipoproteins and was not inhibited by mevinolin, a drug that blocks cholesterol synthesis. These findings suggest that activated platelets may release cholesterol, which can be accumulated by cells and stored as lipid droplets.
EEG Alpha Activity Reflects Attentional Demands, and Beta Activity Reflects Emotional and Cognitive Processes
Authors: Ray William J. , Cole Harry W.
Published: October 2006

Two experiments were designed to examine the effects of attentional demands on the electroencephalogram during cognitive and emotional tasks. We found an interaction of task with hemisphere as well as more overall parietal alpha for tasks not requiring attention to the environment, such as mental arithmetic, than for those requiring such attention. Differential hemispheric activation for beta was found most strongly in the temporal areas for emotionally positive or negative tasks and in the parietal areas for cognitive tasks.
Microinjected c-
myc
as a Competence Factor
Authors: Kaczmarek Leszek , Hyland Julia K. , Watt Rosemary , Rosenberg Martin , Baserga Renato
Published: October 2006

While a number of oncogenes are expressed in a cell cycle-dependent manner, their role in the control of cell proliferation can only be established by a direct functional assay. The c-
myc
protein, upon microinjection into nuclei of quiescent Swiss 3T3 cells, cooperated with platelet-poor plasma in the stimulation of cellular DNA synthesis. This suggests that c-
myc
protein, like platelet-derived growth factor (PDGF), may act as a competence factor in the cell cycle to promote the progression of cells to S phase. The presence in the medium of an antibody against PDGF abolished DNA synthesis induced by microinjected PDGF; however, the microinjected c-
myc
protein stimulated DNA synthesis even when its own antibody was present in the medium. The c-
myc
protein may act as an intracellular competence factor, while PDGF expresses its biological activity only from outside the cells.
Dissociation of Antitumor Potency from Anthracycline Cardiotoxicity in a Doxorubicin Analog
Authors: Sikic Branimir Ivan , Ehsan Mohamed N. , Harker W. Graydon , Friend Nina F. , Brown Byron W. , Newman Robert A. , Hacker Miles P. , Acton Edward M.
Published: October 2006

The search for new congeners of the leading anticancer drug doxorubicin has led to an analog that is approximately 1000 times more potent, noncardiotoxic at therapeutic dose levels, and non-cross-resistant with doxorubicin. The new anthracycline, 3′-deamino-3′-(3-cyano-4-morpholinyl)doxorubicin (MRA-CN), is produced by incorporation of the 3′ amino group of doxorubicin in a new cyanomorpholinyl ring. The marked increase in potency was observed against human ovarian and breast carcinomas in vitro; it was not accompanied by an increase in cardiotoxicity in fetal mouse heart cultures. Doxorubicin and MRA-CN both produced typical cardiac ultrastructural and biochemical changes, but at equimolar concentrations. In addition, MRA-CN was not cross-resistant with doxorubicin in a variant of the human sarcoma cell line MES-SA selected for resistance to doxorubicin. Thus antitumor efficacy was dissociated from both cardiotoxicity and cross-resistance by this modification of anthracycline structure.
Membrane Asymmetry
Authors: Rothman James E. , Lenard John
Published: October 2006

The components of biological membranes are asymmetrically distributed between the membrane surfaces. Proteins are absolutely asymmetrical in that every copy of a polypeptide chain has the same orientation in the membrane, and lipids are nonabsolutely asymmetrical in that almost every type of lipid is present on both sides of the bilayer, but in different and highly variable amounts. Asymmetry is maintained by lack of transmembrane diffusion. Two types of membrane proteins, called ectoproteins and endoproteins, are distinguished. Biosynthetic pathways for both types of proteins and for membrane lipids are inferred from their topography and distribution in the formed cells.

Note added in proof. A cell-free system has now been developed which permits the mechanisms of membrane protein assembly to be studied . The membrane glycoprotein of vesicular stomatitis virus has been synthesized by wheat germ ribosomes in the presence of rough endoplasmic reticulum from pancreas. The resulting polypeptide is incorporated into the membrane, spans the lipid bilayer asymmetrically, and is glycosylated . The amino terminal portion of this transmembrane protein is found inside the endoplasmic reticulum vesicle, while the carboxyl terminal portion is exposed on the outer surface of the vesicle. Furthermore, addition of the glycoprotein to membranes after protein synthesis does not result in incorporation of the protein into the membrane in the manner described above . Consequently, protein synthesis and incorporation into the membrane must be closely coupled. Indeed, using techniques to synchronize the growth of nascent polypeptides, it has been shown that no more than one-fourth of the glycoprotein chain can be made in the absence of membranes and still cross the lipid bilayer when chains are subsequently completed in the presence of membranes. These findings demonstrate directly that the extracytoplasmic portion of an ectoprotein can cross the membrane only during biosynthesis, and not after.
The Structure of a
T
= 1 Icosahedral Empty Particle from Southern Bean Mosaic Virus
Authors: Erickson John W. , Silva Abelardo M. , Murthy M. R. N. , Fita Ignacio , Rossmann Michael G.
Published: October 2006

The structure of a
T
= 1 icosahedral particle (where
T
is the triangulation number), assembled from southern bean mosaic virus coat protein fragments that lacked the amino-terminal arm, was solved by means of model building procedures with the use of 6-angstrom resolution x-ray diffraction data. The icosahedral five-, three-, and twofold contacts were found to be similar, at this resolution, to the analogous contacts (icosahedral five-, quasi-three-, and quasi-twofolds) found in the parent
T
= 3 southern bean mosaic virus. However, the icosahedral fivefold contacts of the
T
= 3 structure are the most conserved in the
T
= 1 capsid. These results are consistent with a mechanism in which pentameric caps of dimers are the building blocks for the assembly of
T
= 1 and
T
= 3 icosahedral viruses.
Hypertension in the Recently Weaned Dahl Salt-Sensitive Rat Despite a Diet Deficient in Sodium Chloride
Authors: Kurtz Theodore W. , Morris R. Curtis
Published: October 2006

The Dahl rat is used as a model of hypertension that is "sensitive" to dietary salt (sodium chloride, NaCl). When dietary salt is supplemented in the Dahl rat, the arterial blood pressure of the "salt-sensitive" strain (S) becomes much greater than that of the "salt-resistant" strain (R). It has been widely reported that arterial blood pressure of the young Dahl S rat is not greater than that of the young Dahl R rat before dietary salt is supplemented. In the present study, however, mean arterial pressure directly measured in unanesthetized, unrestrained S rats was greater than in R rats, both when they had been recently weaned and for at least 10 weeks thereafter, despite their having been fed a diet frankly deficient in salt. In weanling S rats, the ratio of heart weight to body weight was also significantly greater than that in weanling R rats, suggesting that the greater blood pressure in the S rat causes cardiac hypertrophy. Thus, biologic differences demonstrated between the S rat and the R rat after weaning, including the phenomenon of salt-sensitivity, could be a consequence of, or be dependent on, an already extant difference in arterial blood pressure between the two strains.
Natural Variation of Canine Parvovirus
Authors: Parrish Colin R. , O'Connell Priscilla H. , Evermann James F. , Carmichael Leland E.
Published: October 2006

Canine parvovirus was first recognized during 1978. Analysis of isolates collected since its emergence revealed that viruses circulating after 1980 were antigenically different from earlier isolates. Monoclonal antibodies clearly distinguished the two strains, some being specific for either the old or the new viruses. Restriction enzyme analysis of viral DNA's showed that the post-1980 viruses were similar to earlier isolates, but some restriction site differences were present in the new strain. These results suggest that the canine parvoviruses infecting dogs in the seven areas of the United States that were sampled derive from a variant virus that replaced the original strain during 1980.
Artificial Pancreas Using Living Beta Cells: Effects on Glucose Homeostasis in Diabetic Rats
Authors: Chick William L. , Perna John J. , Lauris Vilma , Low David , Galletti Pierre M. , Panol Georg , Whittemore Anthony D. , Like Arthur A. , Colton Clark K. , Lysaght Michael J.
Published: October 2006

An artificial pancreas consisting of beta cells cultured on synthetic semipermeable hollow fibers was tested in rats with alloxan-induced diabetes. When implanted ex vivo as arteriovenous shunts in the circulatory system these devices lowered concentrations of plasma glucose from 533 to between 110 and 130 milligrams per 100 milliliters, increased concentrations of plasma insulin, and restored intravenous glucose tolerance tests essentially to normal.
Dyskinesias Evoked in Monkeys by Weekly Administration of Haloperidol
Authors: Weiss Bernard , Santelli Shirley
Published: October 2006

In two cebus (
Cebus albifrons
) monkeys given weekly oral doses of 0.25 milligram of haloperidol per kilogram, movement disorders appeared 1 to 8 hours after drug administration following the tenth weekly dose. These disorders included oral movements, peculiar postures, writhing, and stretching. Such reactions faded in intensity after the next two doses. Increasing the dose to 0.5 milligram per kilogram has elicited the disorders reliably after each weekly dose for almost 2 years. Similar reactions also developed in a squirrel monkey (
Saimiri sciurea
) treated weekly with haloperidol and in a third cebus monkey previously maintained for a year on a regimen of 0.25 milligram of haloperidol per kilogram on 5 days per week. These findings suggest an experimental model for determining the etiology of drug-induced movement disorders. They also suggest an unrecognized clinical problem.
Induction of Copulatory Behavior in Sexually Inactive Rats by Naloxone
Authors: Gessa G. L. , Paglietti E. , Quarantotti B. Pellegrini
Published: October 2006

The intraventricular injection of D-alanine-methionine-enkephalinamide (D-Ala
2
-Met-enkephalinamide), a synthetic analog of Met-enkephalin that is resistant to enzymatic degradation, inhibits copulatory behavior in sexually vigorous male rats in doses which do not influence motor activity or feeding behavior. This effect is prevented by naloxone, a specific inhibitor of opioid receptors. In addition, injections of naloxone induce copulatory behavior in sexually inactive male rats. These results suggest that endorphins play an important role in the regulation of sexual behavior.
Chicken Gizzard: Relation Between Calcium-Activated Phosphorylation and Contraction
Authors: Hoar Phyllis E. , Kerrick W. Glenn L. , Cassidy Paul S.
Published: October 2006

Of the proteins in mechanically disrupted chicken gizzard fibers (no functional sarcolemma) only the 20,000-dalton light chains of myosin underwent large Ca
2+
-and Sr
2+
-dependent changes in phosphorylation. Phosphorylation closely corresponded with the Ca
2+
- and Sr
2+
-activated tensions. Adenosine 5′-O (3′-thiotriphosphate) only in the presence of Ca
2+
induced irreversible Ca
2+
-insensitive activation of tension and thiophosphorylation of the 20,000-dalton light chains, and blocked incorporation of
32
P from [γ-
32
P]adenosine triphosphate into the myosin light chains.
Teleostean Urophysis: Urotensin II and Ion Transport Across the Isolated Skin of a Marine Teleost
Authors: Marshall William S. , Bern Howard A.
Published: October 2006

The caudal neurosecretory peptide urotensin II rapidly inhibits by 30 percent the short-circuit current across the isolated skin of a marine teleost. The effect appears to be specific and cannot be attributed to actions of epinephrine, urotensin I, or arginine vasotocin. The results strongly suggest that urotensin II may act directly on ion-transporting cells involved in teleostean hypoosmoregulation.
Sites of Transition Between Functional Systemic and Cerebral Arteries of Rabbits Occur at Embryological Junctional Sites
Authors: Bevan John A.
Published: October 2006

The vascular smooth muscle of cerebral blood vessels is relatively insensitive to sympathomimetic stimulation compared with muscle from systemic vessels. The transition in the vertebral artery occurs just rostral to the emergence of that artery from the foramen of the lateral process of the atlas and in the internal carotid artery just before it enters the carotid canal. These sites in the adult correspond to embryological junctions between segments of the vertebral and internal carotid arteries derived from the primitive dorsal aortas and their branches with vessels originating locally from the bilateral longitudinal neural arteries. Topographic patterns of vascular properties may in some cases be explained by the different sites of origin of their primordial mesodermal cells.
Thyroxine Increases Nerve Growth Factor Concentration in Adult Mouse Brain
Authors: Walker Peter , Weichsel Morton E. , Fisher David A. , Guo Shirley M. , Fisher Delbert A.
Published: October 2006

The effects of thyroxine and propylthiouracil on nerve growth factor concentrations in cerebral cortex, cerebellum, and brainstem of adult male mice were assessed by using a sensitive radioimmunoassay for the β-subunit of mouse nerve growth factor. Thyroxine administration significantly increased the concentration of nerve growth factor in all three brain areas compared to control values, whereas propylthiouracil was without effect. These results suggest that thyroid hormones stimulate nerve growth factor synthesis in the mature central nervous system, and raise the possibility that the influence of thyroid hormones on central nervous system development might be mediated or influenced by nerve growth factor.
Histofluorescence Techniques Provide Evidence for Dopamine-Containing Neuronal Elements in Canine Kidney
Authors: Dinerstein R. J. , Vannice J. , Henderson R. C. , Roth L. J. , Goldberg L. I. , Hoffmann P. C.
Published: October 2006

Changes induced by hydrochloric acid in the excitation spectrum of catecholamine fluorophores associated with the innervation of the canine renal vasculature show that there are neuronal elements at the glomerular vascular poles containing predominantly dopamine. In contrast, the catecholamine fluorescence in the periadventitial layer of the arcuate arteries is derived from norepinephrine. The dopamine-containing structures may represent the prejunctional counterpart to the pharmacologically identified dopamine receptors in the renal vasculature. As such, this system may be involved in the normal regulation of renal blood flow and renin release.
Platelet Aggregation Induced by Ultrasound Under Specialized Conditions in Vitro
Authors: Miller Douglas L. , Nyborg W. L. , Whitcomb C. C.
Published: October 2006

Human platelets were induced by 2.1-megahertz ultrasound to form aggregates around gas-filled pores in membranes immersed in platelet-rich plasma. The spatial peak intensities required were only about 16 to 32 milliwatts per square centimeter. Ultrasound generated by a medical Doppler device, whose intensity exceeded this, induced aggregate formation under the same conditions.
Human Language Cortex: Localization of Memory, Syntax, and Sequential Motor-Phoneme Identification Systems
Authors: Ojemann George , Mateer Catherine
Published: October 2006

Subdivisions of the human peri-Sylvian language cortex were derived from stimulation mapping during craniotomies under local anesthesia. Naming, reading, short-term verbal memory, single and sequential orofacial movements, and phoneme identification were tested. Sequential orofacial movements and phoneme identification were altered from the same brain sites and thus identified a common system for language production and understanding. This system surrounded a final motor pathway for speech and was surrounded by a separate short-term verbal-memory system. Between the sequential motor-phoneme identification and memory systems were sites where only naming or reading were altered, including sites related exclusively to syntax.
Clonal Characteristics of Experimentally Induced "Atherosclerotic" Lesions in the Hybrid Hare
Authors: Pearson Thomas A. , Dillman John , Williams Kevin J. , Wolff Jon A. , Adams Robert , Solez Kim , Heptinstall Robert H. , Malmros Haqvin , Sternby Nils
Published: October 2006

The female hybrid hare (
Lepus timidus
×
Lepus europaeus
) is heterozygous for electrophoretically separable, X-linked isoenzymes of glucose-6-phosphate dehydrogenase. The isoenzymes of this animal have been used as cellular markers in the study of the clonal origins of experimentally induced atherosclerotic lesions. Aortic lesions produced in the hybrid hare by feeding cholesterol and injuring the aortic wall with a catheter have been shown to have polyclonal characteristics and in this way are fundamentally different from atherosclerotic fibrous plaques in man.
Primary Bioassay of Human Tumor Stem Cells
Authors: Hamburger Anne W. , Salmon Sydney E.
Published: October 2006

A simple method has been developed to support human tumor stem cell colony growth in soft agar. The technique appears suitable for culture of a variety of neoplasms of differing histopathology. Tumor stem cell colonies arising from different types of cancer have differing growth characteristics and colony morphology. This bioassay should be suitable for clinical studies of effects of anticancer drugs or irradiation on human tumor stem cells.
Hyperalgesia Induced by Naloxone Follows Diurnal Rhythm in Responsivity to Painful Stimuli
Authors: Frederickson Robert C. A. , Burgis Vigo , Edwards J. David
Published: October 2006

A diurnal rhythm was observed in the responsiveness of mice to nociceptive stimuli and in the hyperalgesic activity of naloxone. These rhythms may follow a diurnal rhythmicity in the activity of endogenous opioid peptides and may partly account for previous controversy over the direct action of naloxone in opiate-naive animals.
Brain Grafts Reduce Motor Abnormalities Produced by Destruction of Nigrostriatal Dopamine System
Authors: Perlow Mark J. , Freed William J. , Hoffer Barry J. , Seiger Ake , Olson Lars , Wyatt Richard Jed
Published: October 2006

In order to determine if brain tissue grafts can provide functional input to recipient central nervous system tissue, fetal rat dopamine-containing neurons were implanted adjacent to the caudate nucleus of adult recipients whose endogenous dopaminergic input had been destroyed. The grafts showed good survival and axonal outgrowth. Motor abnormalities, which had been induced by the destruction of the endogenous dopaminergic input to the caudate, were significantly reduced after grafting of the fetal brain tissue. These data suggest that such implants may be potentially useful in reversing deficits after circumscribed destruction of brain tissue.
A Cell Line Expressing Vesicular Stomatitis Virus Glycoprotein Fuses at Low
p
H
Authors: Florkiewicz R.Z. , Rose J. K.
Published: October 2006

A stable cell line expressing a complementary DNA clone encoding the vesicular stomatitis virus glycoprotein fused and formed polykaryons at
p
H 5.5. The formation of polykaryons was dependent on the presence of glycoprotein anchored at the cell surface and could be prevented by incubation of cells with a monoclonal antibody to the glycoprotein. Fusion occurred at a
p
H 0.5 unit lower than that observed for cells infected with vesicular stomatitis virus.
Human T-Cell Leukemia Virus (HTLV-I) Antibodies in Africa
Authors: Saxinger W. , Blattner W. A. , Levine P. H. , Clark J. , Biggar R. , Hoh M. , Moghissi J. , Jacobs P. , Wilson L. , Jacobson R. , Crookes R. , Strong M. , Ansari A. A. , Dean A. G. , Nkrumah F. K. , Mourali N. , Gallo R. C.
Published: October 2006

Antibodies specific for human T-cell leukemia-lymphoma virus type I (HTLV-I) were demonstrated in serum samples from various groups of people in South Africa, Uganda, Ghana, Nigeria, Tunisia, and Egypt. The samples had been collected for other purposes and were presumably selected without bias toward clinical conditions associated with HTLV infections. Regional differences in antibody positivity were observed, indicating widely distributed loci of occurrence of HTLV on the African continent in people of both black and white ancestry. Two patients with high titers of antibody to HTLV-I had some signs of adult T-cell leukemia-lymphoma. In several groups a high frequency of false positive serum reactions was indicated when specific confirmation steps were included in the assay. Further characterization of these sera revealed highly elevated immunoglobulin levels, possibly due to polyclonal activation of immunoglobulin synthesis in these subjects. The possibility that related cross-reactive human retroviruses coexist in the same groups was not eliminated.
Identification of the Putative Transforming Protein of the Human T-Cell Leukemia Viruses HTLV-I and HTLV-II
Authors: Slamon Dennis J. , Shimotohno Kunitada , Cline Martin J. , Golde David W. , Chen Irvin S. Y.
Published: October 2006

The human T-cell leukemia viruses HTLV-I and HTLV-II are unique among the transforming retroviruses of vertebrates in their ability to transform human T cells in vitro and in their close association with human malignancies (T-cell lymphomas and leukemia). Their genomes are relatively simple, containing the genes
gag
,
pol
,
env
, and a 3′ region termed "X." This 3′ region may be responsible for the transforming potential of the viruses. The existence of proteins encoded by the 3′ region has been postulated on the basis of multiple open reading frames. In the present study this region is shown to contain a gene encoding a protein of 40 kilodaltons in HTLV-I and 37 kilodaltons in HTLV-II. It is proposed that these proteins be called, respectively, p40

xI

and p37

xII

.
Suramin Protection of T Cells in Vitro Against Infectivity and Cytopathic Effect of HTLV-III
Authors: Mitsuya Hiroaki , Popovic Mikulas , Yarchoan Robert , Matsushita Shuzo , Gallo Robert C. , Broder Samuel
Published: October 2006

A recently discovered member of the human T-cell leukemia virus (HTLV) family of retroviruses has been etiologically linked to the acquired immune deficiency syndrome (AIDS). This virus, which has been designated HTLV-III, is tropic for OKT4-bearing (helper-inducer) T cells. Moreover, the virus is cytopathic for these cells. Suramin is a drug used in the therapy of Rhodesian trypanosomiasis and onchocerciasis, and it is known to inhibit the reverse transcriptase of a number of retroviruses. Suramin has now been found to block in vitro the infectivity and cytopathic effect of HTLV-III at doses that are clinically attainable in human beings.
HTLV-III in Saliva of People with AIDS-Related Complex and Healthy Homosexual Men at Risk for AIDS
Authors: Groopman Jerome E. , Salahuddin S. Zaki , Sarngadharan M. G. , Markham Phillip D. , Gonda Matthew , Sliski Ann , Gallo Robert C.
Published: October 2006

Peripheral blood leukocytes and saliva from 20 individuals, including four with the acquired immune deficiency syndrome (AIDS), ten with AIDS-related complex (ARC), and six healthy homosexual males at risk for AIDS, were compared as sources of transmissible human T-cell leukemia (lymphotropic) virus type III (HTLV-III), the virus found to be the etiologic agent of AIDS. All of the AIDS and ARC patients and four of the six healthy homosexuals had evidence of prior exposure to HTLV-III as indicated by seropositivity for antibody to HTLV-III structural proteins. Infectious virus was isolated from the peripheral blood of one of the AIDS patients, four of the ARC patients, and two of the healthy homosexual males, consistent with previous reports. HTLV-III was also isolated from the saliva of four of the ARC patients and four of the healthy homosexuals. Virus was also observed by electron microscopy in material prepared by centrifugation of the saliva of one AIDS patient. Although AIDS does not appear to be transmitted by casual contact, the possibility that HTLV-III can be transmitted by saliva should be considered.
Neurotransmitter Receptor Binding in Bovine Cerebral Microvessels
Authors: Peroutka Stephen J. , Moskowitz Michael A. , Reinhard John F. , Snyder Solomon H.
Published: October 2006

Purified preparations of microvessels from bovine cerebral cortex contain substantial levels of alpha-adrenergic, beta-adrenergic, and histamine 1 receptor binding sites but only negligible serotonin, muscarinic cholinergic, opiate, and benzodiazepine receptor binding. Norepinephrine and histamine may be endogenous regulators of the cerebral microcirculation at the observed receptors.
Somatostatin: Occurrence in Urinary Bladder Epithelium and Renal Tubules of the Toad,
Bufo marinus
Authors: Bolaffi Janice L. , Reichlin Seymour , Goodman David B. P. , Forrest John N.
Published: October 2006

Immunohistochemical techniques were used to detect immunoreactive somatostatin-like material in toad urinary bladder epithelium and in kidney distal tubules and collecting ducts. This material has immunological and chromatographic properties identical to those of synthetic cyclic somatostatin. The occurrence of somatostatin-like material in antidiuretic hormone-sensitive portions of the renal urinary system suggests a local regulatory or paracrine role for somatostatin.
Phase Variation of Type 1 Fimbriae in
Escherichia coli
Is Under Transcriptional Control
Authors: Eisenstein Barry I.
Published: October 2006

An operon fusion of the
lac
genes to those required for synthesis of type 1 fimbriae (pili) has been achieved in a K12 strain of
Escherichia coli
lysogenized by the bacteriophage mu
d
(Ap
r
,
lac
). Synthesis of β-galactosidase, therefore, reflected pil gene transcription and was used as a probe of fimbrial regulation. Expression of the operon fusion was found to oscillate, demonstrating that phase variation between fimbriate and nonfimbriate states is under transcriptional control. The transition rates from fimbriate to nonfimbriate were 1.05 × 10
-3
per bacterium per generation and from nonfimbriate to fimbriate, 3.12 × 10
-3
per bacterium per generation.
Tetrahydrobiopterin in Striatum: Localization in Dopamine Nerve Terminals and Role in Catecholamine Synthesis
Authors: Levine Robert A. , Miller Leonard P. , Lovenberg Walter
Published: October 2006

The hydroxylase cofactor, tetrahydrobiopterin, and its biosynthetic system are localized in dopaminergic nerve terminals in the striatum. This conclusion is based on the nearly equivalent loss of tyrosine hydroxylase and tetrahydrobiopterin and its initial biosynthetic enzyme, guanosine triphosphate cyclohydrolase, after injection of 6-hydroxydopamine into the substantia nigra. The role of the hydroxylase cofactor in the regulation of dopamine synthesis is reassessed.
Some Neurons of the Rat Central Nervous System Contain Aromatic-L-Amino-Acid Decarboxylase But Not Monoamines
Authors: Jaeger C. B. , Teitelman G. , Joh T. H. , Albert V. R. , Park D. H. , Reis D. J.
Published: October 2006

Neurons containing the enzyme aromatic-L-amino-acid decarboxylase (AADC) but lacking either tyrosine hydroxylase or serotonin were found in the spinal cord of neonatal and adult rats by light and electron microscopic immunocytochemistry. The majority of these neurons localized to area X of Rexed contact ependyma. Thus, spinal AADC neurons have the enzymatic capacity to catalyze directly the conversion of the amino acids tyrosine, tryptophan, or phenylalanine to their respective amines tyramine, tryptamine, or phenylethylamine. These amines normally present in the central nervous system may be of potential clinical significance as endogenous psychotomimetics.
Spontaneous Orofacial Dyskinesia and Dopaminergic Function in Rats After 6 Months of Neuroleptic Treatment
Authors: Waddington John L. , Cross Alan J. , Gamble Stephen J. , Bourne Rachel C.
Published: October 2006

A syndrome of spontaneous orofacial dyskinesia was identified in groups of rats treated for 6 months with a wide range of neuroleptic drugs. Phenothiazines, thioxanthenes, and substituted benzamides were particularly likely to induce the syndrome. It was observed in the presence of a functional blockade of dopamine receptors and endured for at least 2.5 months after drug withdrawal. There was no relation between the syndrome and changes in striatal dopamine receptors, as indexed by the binding of tritiated spiperone and tritiated
cis
(Z)-flupenthixol. The syndrome parallels several of the features of clinical tardive dyskinesia, whose pathophysiology thus may not involve changes in the characteristics of striatal dopamine receptors.
View Through a Window May Influence Recovery from Surgery
Authors: Ulrich Roger S.
Published: October 2006

Records on recovery after cholecystectomy of patients in a suburban Pennsylvania hospital between 1972 and 1981 were examined to determine whether assignment to a room with a window view of a natural setting might have restorative influences. Twenty-three surgical patients assigned to rooms with windows looking out on a natural scene had shorter postoperative hospital stays, received fewer negative evaluative comments in nurses' notes, and took fewer potent analgesics than 23 matched patients in similar rooms with windows facing a brick building wall.
Turnover of Inositol Phospholipids and Signal Transduction
Authors: Nishizuka Yasutomi
Published: October 2006

Various extracellular informational signals such as those from a group of hormones and some neurotransmitters appear to be passed from the cell surface into the cell interior by two routes, protein kinase C activation and Ca
2+
mobilization. Both routes usually become available as the result of an interaction of a single ligand and a receptor and act synergistically to evoke subsequent cellular responses such as release reactions. The signal-dependent breakdown of inositol phospholipids, particularly phosphatidylinositol bisphosphate, now appears to be a key event for initiating these processes.
Inhibition of Cell Motility by Interferon
Authors: Brouty-Boyé Danièle , Zetter Bruce R.
Published: October 2006

Interferon derived from human leukocytes, human fibroblasts, and mouse fibroblasts was found to inhibit the motility of cultured cells. It inhibits the tumor-induced motility of capillary endothelial cells as well as the spontaneous migration of other cell types. The ability of a given preparation of interferon to inhibit the motility of a given cell type is proportional to its antiviral activity in that particular cell type. Antiserum to human leukocyte interferon neutralizes both the motility-inhibitory activity and the antiviral activity of this preparation.
Histamine-Mediated Delayed Permeability Response After Scald Burn Inhibited by Cimetidine or Cold-Water Treatment
Authors: Boykin Joseph V. , Eriksson Elof , Sholley Milton M. , Pittman Roland N.
Published: October 2006

Scald injury to one ear of the hairless mouse induced significant (
P
< .05) delayed edema formation in remote, uninjured skin. This remote edema formation was completely inhibited by immediate cold-water treatment of the scalded ear. Cold-water treatment significantly reduced histamine loss from the scalded ear, and the edema-inhibiting effect of the treatment could be mimicked by treating the animal prior to injury with the H
2
-histamine receptor antagonist cimetidine or a drug that causes histamine depletion. These observations suggest (i) that a histamine-mediated, delayed permeability response occurs after thermal injury that causes remote edema formation and (ii) that one mechanism of remote edema inhibition by cold-water treatment is the prevention of histamine release from thermally injured tissues.
Effect of Interferon-α1 from
E. coli
on Some Cell Functions
Authors: Masucci Maria Grazia , Szigeti Robert , Klein Eva , Klein George , Gruest Jacqueline , Montagnier Luc , Taira Hideharu , Hall Alan , Nagata Shigekazu , Weissmann Charles
Published: October 2006

Interferon-α1 from
Escherichia coli
transformed with a hybrid plasmid containing a human leukocyte complementary DNA insert, induces resistance to virus in appropriate target cells. It also shares the following properties with natural leukocyte interferon (IFN). (i) It enhances natural killing activity of human lymphocytes, (ii) it enhances antibody-dependent cell-mediated cytotoxicity, (iii) it suppresses antigen- and mitogen-induced leukocyte migration inhibition, (iv) it inhibits growth of IFN-sensitive Burkitt lymphoma cells. Since these activities are exhibited by a cloned protein species, they are due to IFN itself and not to other human proteins.
5-Azacytidine-Induced Reactivation of a Herpes Simplex Thymidine Kinase Gene
Authors: Clough David W. , Kunkel Louis M. , Davidson Richard L.
Published: October 2006

Mouse cells transformed with herpes simplex virus and containing the viral thymidine kinase (TK) gene in an inactive state were treated with 5-azacytidine. The result was the reexpression of the viral TK gene. Two days of exposure to 5-azacytidine followed by 2 days of expression time was sufficient for maximal induction of the TK
+
phenotype. The induction of TK expression by 5-azacytidine was concentration-dependent, with maximal induction at 10 micromoles per liter. 5-Azacytidine also inhibited the decay of TK expression in TK
+
transformants removed from selective conditions. Analysis of the methylation patterns of the viral TK gene with restriction endonucleases Hpa II and Msp I showed the active gene to be unmethylated, the inactive gene methylated, and the 5-azacytidine-induced gene unmethylated.
Fast Axonal Transport in Extruded Axoplasm from Squid Giant Axon
Authors: Brady Scott T. , Lasek Raymond J. , Allen Robert D.
Published: October 2006

Development of video-enhanced contrast-differential interference contrast for light microscopy has permitted study of both orthograde and retrograde fast axonal transport of membranous organelles in the squid giant axon. This process was found to continue normally for hours after the axoplasm was extruded from the giant axon and removed from the confines of the axonal plasma membrane. It is now possible to follow the movements of the full range of membranous organelles (30-nanometer vesicles to 5000-nanometer mitochondria) in a preparation that lacks a plasma membrane or other permeability barrier. This observation demonstrates that the plasma membrane is not required for fast axonal transport and suggests that action potentials are not involved in the regulation of fast transport. Furthermore, the absence of a permeability barrier surrounding the axoplasm makes this an important model for direct biochemical pharmacological, and physical manipulations of membranous organelle transport.
Genetic Expression in the Developing Brain
Authors: Chaudhari Nirupa , Hahn William E.
Published: October 2006

The adult mouse brain contains complex populations of polyadenylated [poly(A)
+
] and nonpolyadenylated [poly(A)
-
] messenger RNA's (mRNA's). These mRNA's are separate sequence populations, similar in complexity, and in combination are equivalent to ∼ 150,000 different mRNA sequences, of average length. Essentially all of the "adult" poly(A)
+
mRNA's are present in the brain at birth. In contrast, most of the poly(A)
-
mRNA's are absent. Brain poly(A)
-
mRNA's begin to appear soon after birth, but the full adult complement is not reached until young adulthood. This suggests that these poly(A)
-
mRNA's specify proteins required for the biological capabilities of the brain that emerge during the course of postnatal development.
Angiogenesis Inhibition and Tumor Regression Caused by Heparin or a Heparin Fragment in the Presence of Cortisone
Authors: Folkman Judah , Langer Robert , Linhardt Robert J. , Haudenschild Christian , Taylor Stephanie
Published: October 2006

Heparin or a heparin fragment administered with cortisone inhibited angiogenesis, caused regression of large tumor masses, and prevented metastases. Oral administration of heparin resulted in the release of non-anticoagulant heparin fragments in the serum which, in the presence of cortisone, had similar anti-angiogenic and antitumor effects. Of all the heparin fragments tested, the most potent inhibition of angiogenesis in the presence of cortisone was provided by a hexasaccharide with a molecular weight of about 1600.
Zinc Deficiency in Murine Milk Underlies Expression of the
Lethal Milk
(
lm
) Mutation
Authors: Piletz John E. , Ganschow Roger E.
Published: October 2006

The inability of nursing pups to survive on milk of mice homozygous for the recessive mutation,
lethal milk
(
lm
), is correlated with a reduction in zinc levels of both milk and pup carcass. Administration of zinc to pups nursing on
lmlm
dams reduces the observed mortality and morbidity. It is suggested that lm alters zinc transport from maternal blood to milk and that its study may provide useful information for understanding the rare human disease, acrodermatitis enteropathica.
Virus Persists in β Cells of Islets of Langerhans and Is Associated with Chemical Manifestations of Diabetes
Authors: Oldstone Michael B. A. , Southern Peter , Rodriquez Moses , Lampert Peter
Published: October 2006

Molecular hybridization, monoclonal antibody, and electron microscopic analyses showed lymphocytic choriomeningitis virus (strains Armstrong and WE) persistently infecting cells of the islets of Langerhans in BALB/WEHI mice. When monoclonal or monospecific antibody conjugated with two different fluorochrome dyes was used to mark insulin-containing β cells or viral antigens, viral nucleoprotein was identified predominately in β cells. Electron microscopy confirmed these findings by showing virions budding from the β cells. Persistent infection was associated with chemical evidence of diabetes (hyperglycemia, abnormal glucose tolerance, and normal or low-normal concentrations of insulin). Concentrations of cortisol and insulin-like growth factor in blood were normal, as was the level of growth hormone in the pituitary gland. The virus-infected islet cells showed normal anatomy and cytomorphology. Neither cell lysis nor inflammatory infiltrates were routinely seen. Thus a virus may persistently infect islet cells and provide a biochemical and morphological picture comparable to that of early adult-onset diabetes mellitus in humans.
Durations of Unitary Synaptic Potentials Help Time a Behavioral Sequence
Authors: Wine Jeffrey J. , Hagiwara Grace
Published: October 2006

Recordings in identified neurons and muscles that mediate crayfish tailflips reveal inhibitory postsynaptic potentials of two distinct durations. Those of long duration are recorded in five classes of cells in the flexion circuit, while those of short duration are recorded in three classes of cells in the extension circuit. The durations of the inhibitory postsynaptic potentials are matched to the durations of inhibition required by the different phases of the behavior.
Opiate Receptor Function May Be Modulated Through an Oxidation-Reduction Mechanism
Authors: Marzullo Giovanni , Hine Bromfield
Published: October 2006

Cupric ion, a thiol oxidant, caused naloxone-reversible analgesia when injected intracerebroventricularly in mice; its potency was close to that of morphine. Dithiothreitol, a thiol reductant, reversed the analgesia induced by cupric ion and antagonized analgesia induced by morphine. Oxidized dithiothreitol had no effect. These findings, together with evidence for redox modification of opiate receptor binding in vitro, suggest that a mechanism of oxidation-reduction of thiols may modulate opiate receptor function.
Genetic Variation in the Human Insulin Gene
Authors: Ullrich Axel , Dull Thomas J. , Gray Alane , Brosius Jürgen , Sures Irmi
Published: October 2006

Four recombinant lambda phages containing nucleotide sequences complementary to a cloned human preproinsulin DNA probe have been isolated from human DNA. Restriction analyses in conjunction with Southern hybridizations reveal two types of gene sequences. One isolate of each type was subjected to complete nucleotide sequence determination. The sequences contain the entire preproinsulin messenger RNA region, two intervening sequences, 260 nucleotides upstream from the messenger RNA capping site, and 35 nucleotides beyond the polyadenylate attachment site. Our results strongly suggest that these two gene types are allelic variants of a single insulin gene.
GABA Analogues Activate Channels of Different Duration on Cultured Mouse Spinal Neurons
Authors: Barker Jeffery L. , Mathers David A.
Published: October 2006

Voltage-clamp recordings from mouse spinal neurons grown in culture were used to study the membrane current fluctuations induced by 12 substances structurally similar to γ-aminobutyric acid (GABA). Fluctuation analysis provided estimates of the electrical properties of the elementary events underlying these responses. Estimates of the mean conductance of channels activated by all of the substances except glycine did not differ significantly from that estimated for GABA, whereas mean durations of agonist-activated channels all differed significantly from that found for GABA. The results indicate that all of the substances tested except glycine activate channels of similar conductance but of different durations.
Stress-Induced Analgesia in Humans: Endogenous Opioids and Naloxone-Reversible Depression of Pain Reflexes
Authors: Willer Jean Claude , Dehen Henri , Cambier Jean
Published: October 2006

The cumulative effects of a repetitive stress induced by anticipation of pain (noxious foot shock) were studied on the threshold of a nociceptive flexion reflex of the lower limb. The threshold of the nociceptive reflex progressively increased with the repetition of the stress. This effect was reversed by naloxone, which even produced hyperalgesia, since a rapid and significant decrease in this threshold, below the initial values, was noted. The data provide evidence for involvement of endogenous opioids in the phenomenon of stress-induced analgesia in normal man.
Growth Inhibition by Adenosine 3′,5′-Monophosphate Derivatives Does Not Require 3′,5′ Phosphodiester Linkage
Authors: Martin Thomas F. J. , Kowalchyk Judith A.
Published: October 2006

Analogs of adenosine 3′,5′-monophosphate (cyclic AMP) inhibit the growth of cultured cell lines. The effects of 8-bromo- and N6-butyryl-substituted analogs of cyclic and noncyclic AMP on six cell lines were examined and were equally inhibitory. Variant cell lines with altered cyclic AMP-dependent protein kinase were more resistant to both cyclic and noncyclic nucleotides. We conclude that growth inhibition by analogs of cyclic AMP (i) does not require a 3′,5′ phosphodiester bond and (ii) may be mediated by a pathway involving endogenous cyclic AMP.
Both ν and δ Opiate Receptors Exist on the Same Neuron
Authors: Egan Terry M. , North R. Alan
Published: October 2006

Low concentrations of the relatively selective opiate receptor agonists dihydromorphine and normorphine (μ receptor agonists) and D-Ala
2
-D-Leu
5
-enkephalin (a δ receptor agonist) were applied to single enteric neurons while the frequency of action potential firing was recorded. Most neurons that were inhibited by the μ agonists were also inhibited by the δ agonist, but the two receptors could be distinguished by the higher concentration of naloxone required to antagonize the δ agonist. The results indicate that enteric neurons bear both μ and δ receptors and that cell firing is inhibited if either receptor type is activated.
Integration and Stable Germ Line Transmission of Genes Injected into Mouse Pronuclei
Authors: Gordon Jon W. , Ruddle Frank H.
Published: October 2006

Genetic material has been successfully transferred into the genomes of newborn mice by injection of that material into pronuclei of fertilized eggs. Initial results indicated two patterns of processing the injected DNA: one in which the material was not integrated into the host genome, and another in which the injected genes became associated with high molecular weight DNA. These patterns are maintained through further development to adulthood. The evidence presented indicates the covalent association of injected DNA with host sequences, and transmission of such linked sequences in a Mendelian distribution to two succeeding generations of progeny.
Regulation of Muscle Differentiation: Stimulation of Myoblast Fusion in Vitro by Catecholamines
Authors: Curtis David H. , Zalin Rosalind J.
Published: October 2006

Epinephrine and isoproterenol provoke primary chick myoblasts to initiate precocious cell fusion. Both the rise in intracellular adenosine 3′,5′-monophosphate (cyclic AMP) and cell fusion generated by these effectors are prevented by propranolol, which is a specific blocker of the β-adrenergic receptor. Propranolol has no effect either on the precocious cell fusion provoked by prostaglandin E or on cell fusion in control cultures. The results support the idea that a rise in cyclic AMP is the critical intracellular change responsible for initiating events that culminate in myoblast differentiation 4 to 5 hours later. They also indicate that the hormone responsible for the positive regulation of myoblast differentiation in vitro is not acting through the β-adrenergic receptor.