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Showing papers by "University of Virginia published in 1973"


Journal ArticleDOI
TL;DR: The structure of crystalline carp muscle calcium-binding protein (parvalbumin) has been determined by x-ray diffraction techniques to nominal 1.85-A resolution and the electron density map is interpreted in terms of the 108 amino acid sequence described in Paper I in this series.

1,325 citations


Journal ArticleDOI
TL;DR: A simple procedure is described for removal of Triton X-100 from protein samples by adsorption of the detergent on a commercial copolymer in bead form with no loss or dilution of protein.

834 citations


Journal ArticleDOI
TL;DR: The length-tension relationships for arterial smooth muscle were determined using vascular strips teased from the media of hog carotid arteries using potassium-induced depolarization and Norepinephrine and electric field stimulation.
Abstract: The length-tension relationships for arterial smooth muscle were determined using vascular strips teased from the media of hog carotid arteries. Histological examination revealed that the strips were (1) free of adventitia and (2) composed of smooth muscle cells oriented parallel to the long axis of the strips. Measurements from electron micrographs indicated that 60% of the cross-sectional area consisted of smooth muscle. At L 0 (the optimal length for tension development) the total cross-sectional area of the strips varied from 0.3 to 0.8 mm 2 . Potassium-induced depolarization was the most effective stimulus for force development. Norepinephrine and electric field stimulation elicited responses which were 70% and 30%, respectively, of that produced by potassium-induced depolarization. At L 0 the intrinsic load-bearing capacity (P 0 ) of the contractile system was 2.22 x 10 6 dynes/cm 2 . Tension development fell off gradually at lengths shorter than L 0 and more rapidly at lengths greater than L 0 . Passive length-tension curves were determined after quick releases from higher to lower lengths to avoid complications arising from tone. Passive tension was negligible at lengths below 0.9 L 0 . At L 0 the passive tension was 10% of P 0 .

300 citations


Journal ArticleDOI
TL;DR: An analysis of the shape of the same bone affected at different periods of prenatal development led to the following proposal: at earlier stages retinoic acid disrupts cellular activities that normally lead to the spatial organization of the mesenchymal cell condensations, resulting in a modifiedshape of the cartilage models; at later stages it prevents the enlargement of the condensation that have already appeared, resultingIn smaller than normal models.
Abstract: Retinoic (vitamin A) acid produced phocomelia and micromelia in DBA/2J fetuses when administered to pregnant mice on the 12th or 13th day of gestation. The incidence of forelimb defects was higher after 12th- (in embryos having 33–41 somite pairs) than 13th–day treatment (40–51 somite pairs); the reverse was true for hindlimb defects. Hindlimb digits continued to be highly susceptible on the 14th day. Limb defects were not accompanied by body growth retardation or other skeletal malformations except cleft palate. The type and severity of limb defects depended on the average developmental stage of the limb bud at the time of treatment. From the beginning of the period of limb susceptibility, the 12th day, the ontogenetic sequence in which the long bones were rendered abnormal was: radius–ulna, humerus, fibula, tibia, femur or tibia-femur. The sequence in which the long bones lost their susceptibility to retinoic acid was: humerus, femur, ulna, radius, tibia-fibula. The radius appeared to be susceptible in some embryos at a time when the other long bones had escaped injury. An analysis of the shape of the same bone affected at different periods of prenatal development led to the following proposal. At earlier stages retinoic acid disrupts cellular activities that normally lead to the spatial organization of the mesenchymal cell condensations, resulting in a modified shape of the cartilage models; at later stages it prevents the enlargement of the condensations that have already appeared, resulting in smaller than normal models.

272 citations


Journal ArticleDOI
TL;DR: Evidence is presented that these B(12) receptor sites also function as the receptors for the E colicins, and that there is competition between B( 12) and the E Colicins for occupancy of these sites.
Abstract: The first step in the transport of cyanocobalamin (CN-B(12)) by cells of Escherichia coli was shown previously to consist of binding of the B(12) to specific receptor sites located on the outer membrane of the cell envelope. In this paper, evidence is presented that these B(12) receptor sites also function as the receptors for the E colicins, and that there is competition between B(12) and the E colicins for occupancy of these sites. The cell strains used were E. coli KBT001, a methionine/B(12) auxotroph, and B(12) transport mutants derived from strain KBT001. Colicins E1 and E3 inhibited binding of B(12) to the outer membrane B(12) receptor sites, and CN-B(12) protected cells against these colicins. Half-maximal protection was given by CN-B(12) concentrations in the range of 1 to 6 nM, depending upon the colicin concentration used. Colicin E1 competitively inhibited the binding of (57)Co-labeled CN-B(12) to isolated outer membrane particles. Functional colicin E receptor sites were found in cell envelopes from cells of only those strains that possessed intact B(12) receptors. Colicin K did not inhibit the binding of B(12) to the outer membrane receptor sites, and no evidence was found for any identity between the B(12) and colicin K receptors. However, both colicin K and colicin E1 inhibited the secondary phase of B(12) transport, which is believed to consist of the energy-coupled movement of B(12) across the inner membrane.

254 citations


Journal ArticleDOI
TL;DR: The gold-treated patients showed slight, but definite, improvement in all parameters measured, although only the change in sedimentation rate was statistically significant, although the number of patients treated was too small to allow definite conclusions.
Abstract: Sixty-eight patients with definite or classic rheumatoid arthritis were enrolled in a double-blind, controlled study of gold salt therapy. The initial phase compared weekly injections of gold thiomalate to placebo. One-third of the gold group were withdrawn from the trial because of toxicity and one-fourth of the controls because of no benefit. The gold-treated patients showed slight, but definite, improvement in all parameters measured, although only the change in sedimentation rate was statistically significant. In Phase 2, designed to ascertain the effects of maintenance therapy, the gold group showed no increase in the number of involved joints, improved their grip strength and had a fall in erythrocyte sedimentation rate. Over the same period the placebo group deteriorated in all these parameters. The number of patients treated, however, was too small to allow definite conclusions.

209 citations


Journal ArticleDOI
TL;DR: The cheek pouch is a useful microcirculatory preparation which has both advantages and disadvantages as outlined below and should be chosen for use with these characteristics in mind.

207 citations


Journal ArticleDOI
TL;DR: Alpha-delta sleep is an EEG defined sleep stage which consists of 5–20% delta waves mixed with large amplitude alpha waves mixed at low Hz, and appears to replace delta sleep in some patients with chronic, somatic malaise and fatigue.

191 citations


Journal ArticleDOI
TL;DR: Outer membrane protein of Escherichia coli prepared for polyacrylamide gel electrophoresis by solubilization of the membrane in an organic solvent followed by dialysis into sodium dodecyl sulfate (SDS) solution and brief heating at 100 °C resulted in a simple polypeptide profile on SDS-containing gels.

177 citations



Journal ArticleDOI
TL;DR: The results suggest that the carbohydrate metabolism of the isolated liver cells closely resembles that of the intact, perfused liver.

Journal ArticleDOI
TL;DR: Insulin activates glycogen synthase previously inactivated by glucagon in isolated perfused livers from normal rats, while increasing [14C]glucose incorporation into glycogen and decreasing glucagon-stimulated glucose production, resulting in a change in synthase activity.

Journal ArticleDOI
TL;DR: The process of retinal degeneration and regeneration in retinectomized or enucleated and reimplanted eyes of adult Notophthalmus viridescens has been studied following staged administrations of tritiated thymidine or colchicine to demonstrate a different sequence for retinal restoration.
Abstract: The process of retinal degeneration and regeneration in retinectomized or enucleated and reimplanted eyes of adult Notophthalmus viridescens has been studied following staged administrations of tritiated thymidine or colchicine. In control left eyes, no labeled cells were observed in either the retina, pigment epithelium, or ora serrata. In retinectomized or enucleated eyes, retinal degeneration proceeded from the posterior central pole circumferentially to the ora serrata, with complete retinal degeneration being consistently observed. Retinal replacement originated from two cellular sources: the posterior pigment epithelium and the anterior complex, consisting of cells in the ora serrata and pars ciliaris retina. The posterior pigment epithelium gave rise to an initial central retinal portion which differentiated in an annular pattern which extended from the optic nerve to the vortex veins. Cellular addition from the pigment epithelium became restricted to these two regions by day 25. The anterior retinal mass was regenerated from the anterior elements (ora serrata/pars ciliaris retina) with a minor contribution from the underlying anterior pigment epithelium. Data concerning the relative numbers of cellular types involved in the regenerative sequence and the times of their function are presented. Peak labeling occurred in the posterior pigment epithelium at day 20, the pars ciliaris retina at days 18 and 40, and the new retina at days 28 and 41. By 30 days regional sites of cellular proliferation became established that coincided with the pattern of ocular blood vessels. Retinal differentiation followed the pattern commonly observed during retinal development. The significance of these observations with respect to earlier work demonstrating a different sequence for retinal restoration is discussed.

Journal ArticleDOI
TL;DR: It was demonstrated that L protein, but not NS protein, was required for in vitro RNA synthesis on the VS viral nucleocapsid template, and it was concluded that the L protein functions as the transcriptase, and the nucleocapid NS protein is not essential for in vivo RNA synthesis.
Abstract: The endogenous transcriptase present in purified vesicular stomatitis (VS) virions was solubilized with a Triton X-100 high-salt solution. The polymerase activity was purified on glycerol gradients and by phosphocellulose column chromatography; the viral proteins present in the active enzyme fractions were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis. It was demonstrated that L protein, but not NS protein, was required for in vitro RNA synthesis on the VS viral nucleocapsid template. Solubilized L protein rebinds to the ribonucleoprotein template when the transcription complex is reconstituted, and the RNA synthesized in vitro by purified L protein hybridizes to virion RNA. Cyanogen bromide peptide fingerprints indicate that the large L protein is a unique polypeptide chain. It is concluded that the L protein functions as the transcriptase, and the nucleocapsid NS protein is not essential for in vitro RNA synthesis.

Journal ArticleDOI
TL;DR: The specific capacitance of thin lipid films formed from a chromatographically pure synthetic phospholipid in n -decane was studied in detail to examine the validity of these assumption and it was concluded that the bilayer films studied must have a non-reproducible stoichiometry and anon-uniform thickness.

Journal ArticleDOI
TL;DR: The proposed theory states that individuals are the generating force behind the origin, spread, and transformations of sociocultural complexes and that all sociOCultural phenomena are explicable in terms of the differential replication of ideas by individuals as this is conditioned by selective pressures generated by particular material conditions of life.
Abstract: By introducing the concept of the natural selection of individual organisms, Darwin was able to cut through the mystification surrounding theological discussions of the origin of species. By placing the concept of an individual “struggle for satisfaction” in an analogous conceptual framework, a similar feat may be performed with regard to the mystification and reification surrounding much of contemporary social science. The proposed theory states that individuals are the generating force behind the origin, spread, and transformations of sociocultural complexes and that all sociocultural phenomena are explicable in terms of the differential replication of ideas by individuals as this is conditioned by selective pressures generated by particular material conditions of life. The theory is used to illuminate certain key issues in evolution, such as adaptation, group selection, and free will


Journal ArticleDOI
TL;DR: The mechanical responses of isolated arterial smooth muscle strips to alterations in bathing solution oxygen tension (PO2) were investigated to determine the extent to which diffusion of oxygen limits in vitro contractile performance of vascular smooth muscle.

Journal ArticleDOI
TL;DR: Although no distinct rhythm of testosterone was discernible when the various curves were examined separately, an analysis of variance of the results obtained on all 6 subjects revealed a significant circadian variation.
Abstract: The hourly integrated concentrations of testosterone and LH in the plasma of 6 young adult, normal men were determined during 24 hr of normal activity and sleep. A portable non-thrombogenic pump system was used for the constant blood withdrawal. Although no distinct rhythm of testosterone was discernible when the various curves were examined separately, an analysis of variance of the results obtained on all 6 subjects revealed a significant (p < 0.0005) circadian variation, the peak of the mean levels being at 6–7 am (675 ng/100 ml) and the lowest values being reached at 7–8 PM (464 ng/100 ml). However, only 20% of the variation in plasma testosterone levels were time-related, while 80% of the variation was random in nature. The small amplitude of the changes and the individual variations render difficult the physiological interpretation of the circadian rhythm of plasma testosterone. No significant circadian rhythm of plasma LH could be demonstrated and there was no significant correlation betwe...

Journal ArticleDOI
TL;DR: There is no evidence to confirm the identity of any specific carbohydrate which is essential for receptor activity, but preliminary analysis indicated that glucose, galactose (and/or heptose), rhamnose, uronic acids, and amino sugars were present in the purified receptor fraction.

Journal ArticleDOI
TL;DR: Using counterimmunoelectrophoresis, DNA was found in plasma in a variety of illnesses which are delineated in this study and is at least ten times more sensitive than simple immunodiffusion in the detection of DNA.
Abstract: Using counterimmunoelectrophoresis, DNA may be detected at concentrations as low as 1.5 μ/ml in plasma and 0.2 μg/ml in serum. Serum, however, was not suitable for this study because DNA was sporadically released into serum during the clotting process. Counterimmunoelectrophoresis is at least ten times more sensitive than simple immunodiffusion in the detection of DNA. DNA was found in plasma in a variety of illnesses which are delineated in this study.

Journal ArticleDOI
TL;DR: These findings, together with additional data in the literature, suggest that thiazides may potentiate the renal action of parathyroid hormone, resulting in retention of calcium and partial suppression of par Kathyroid hormone secretion.
Abstract: Thiazide diuretics reduce urinary excretion of calcium by about 40% in patients with intact parathyroid glands (normal parathyroid function or primary hyperparathyroidism). Despite equivalent sodium losses, thiazide diuretics do not lower calcium excretion in patients with hypoparathyroidism. Thiazide diuretics diminish hydroxyproline excretion by about 22%, and they do not affect 3′5′-cyclic AMP excretion in subjects with intact parathyroid glands. These findings, together with additional data in the literature, suggest that thiazides may potentiate the renal action of parathyroid hormone, resulting in retention of calcium and partial suppression of parathyroid hormone secretion.

Journal ArticleDOI
TL;DR: The presumptive B12 receptor on this membrane must recognize B12 only when the B12 is attached to some specific donor molecule, which would indicate an essential similarity between the B 12 uptake systems of the E. coli inner membrane and mammalian plasma membranes.

Journal ArticleDOI
TL;DR: There is much clinical and subjective support for the notion that academic underachievers of normal intelligence (learning disabled children) exhibit both impulsivity and poor attention as discussed by the authors, and there is also some evidence that underachieving children exhibit poor attention.
Abstract: There is much clinical and subjective support for the notion that academic underachievers of normal intelligence (learning disabled children) exhibit both impulsivity and poor attention. This study...

Journal ArticleDOI
30 Nov 1973-Science
TL;DR: In this paper, the authors found that cyclic AMP can be used as a beat-to-beat regulator of myocardial contractility, and that peak concentrations of cyclic amp follow peak development of systolic tension.
Abstract: The concentration of adenosine 39,59-monophosphate (cyclic AMP) rises and falls during each myocardial contraction cycle. Peak concentrations of cyclic AMP precede peak development of systolic tension. Epinephrine alters the normal oscillation in myocardial cyclic AMP and increases both diastolic and systolic concentrations of the cyclic nucleotide. These transient changes in myocardial cyclic AMP indicate a potential role for cyclic AMP as a beat-to-beat regulator of myocardial contractility.

Journal ArticleDOI
TL;DR: Negative selection by penicillin treatment or positive selection with phosphonomycin was employed on mutants of Escherichia coli defective in the hexose phosphate transport system, and revertants of some of the mutants exhibited altered regulatory control of this transport system.
Abstract: Mutants of Escherichia coli defective in the hexose phosphate transport system were isolated. Negative selection by penicillin treatment or positive selection with phosphonomycin was employed. These mutants grew normally on all carbon sources other than hexose phosphates. The map location of the mutations in 18 independently isolated mutant strains was investigated by transduction crosses. All of the mutations were found to lie in the same region of the chromosome, in the region represented by min 72 on the Taylor map. The order of the genes in this region was found to be mtl-cysE-pyrE-uhp-bgl-ilv. Revertants of some of the mutants exhibited altered regulatory control of this transport system.

Journal ArticleDOI
TL;DR: Because of the initial distribution of essential metabolic reserves within a transected fiber and because of the changes which occur in that distribution with time, autolysis evolves in a somatofugal manner in axon proper and decelerates in preterminal-terminal regions.

Journal ArticleDOI
02 Nov 1973-Science
TL;DR: It is shown thatptic nerve stimulation in the shark evokes short-latency telencephalic field potentials localized to the ipsilateral, posterior central nucleus, which further challenges classical formulations of forebrain evolution and confirms recent evidence for a crossed thalamotelenced visual projection.
Abstract: Optic nerve stimulation in the shark evokes short-latency telencephalic field potentials localized to the ipsilateral, posterior central nucleus. Such a well-defined visual area in elasmobranch telencephalon further challenges classical formulations of forebrain evolution. Moreover, its ipsilateral representation confirms recent evidence for a crossed thalamotelencephalic visual projection.

Journal ArticleDOI
TL;DR: A paroxysm-triggered method for measuring reaction time at specific time points during spike-wave discharge has been developed, and reaction times measured at varying intervals after the onset of the paroxym, which could be considered evidence for a gradual decrease in responsiveness.

Journal ArticleDOI
TL;DR: Rats with electrolytic lesions of the posteroventral hippocampus failed to perform a simple passive avoidance of footshock but showed conditioned aversion to a saccharin solution paired with apomorphine induced gastrointestinal distress, and anterodorsal hippocampal lesions interfered with performance on both tasks.