Showing papers by "University of California, San Diego published in 1981"
TL;DR: It was found that treatment of gels with dithiothreitol prior to impregnation with silver nitrate results in more reproducible staining patterns that are also qualitatively similar to those obtained with Coomassie blue.
4,022 citations
TL;DR: In this paper, it was suggested that some aspects of this practice should be brought out into the open, and the type of equations to be considered are generating equations, so that a simulation of the explanatory side should produce the major properties of the variable being explained.
2,482 citations
TL;DR: A comparative analysis and new data allow a consistent and accurate set of optical properties for the clearest natural waters and for pure fresh water and saltwater to be estimated from 300 to 800 nm.
Abstract: A new UV submersible spectroradiometer has been employed to determine the diffuse attenuation coefficient for irradiance in the clearest natural waters [K;(X)] with emphasis on the spectral region from 300 to 400 nm. K (X) can be related to the inherent optical properties of pure water, in particular the total absorption coefficient a,,(X) and the molecular scattering coefficient bm(X), by means of equations derived from radiative transfer theory. We present an analysis showing that limiting values of K. (X) can be estimated from aw(X) and vice versa. Published a (X) data, which show discrepancies much larger than their estimated accuracies, are briefly reviewed and then compared, via our analysis, with K, (X) data (our own new and previously published data as well as relevant data of others). This comparative analysis and new data allow a consistent and accurate set of optical properties for the clearest natural waters and for pure fresh water and saltwater to be estimated from 300 to 800 nm.
1,634 citations
TL;DR: The systemic comparison of every newly determined amino acid sequence with all other known sequences may allow a complete reconstruction of the evolutionary events leading to contemporary proteins, but sometimes the surviving similarities are so vague that even computer-based sequence comparisons procedures are unable to validate relationships.
Abstract: The systemic comparison of every newly determined amino acid sequence with all other known sequences may allow a complete reconstruction of the evolutionary events leading to contemporary proteins. But sometimes the surviving similarities are so vague that even computer-based sequence comparisons procedures are unable to validate relationships. In other cases similar sequences may appear in totally alien proteins as a result of mere chance or, occasionally, by the convergent evolution of sequences with special properties.
793 citations
TL;DR: The authors measured intracarpal canal pressures with the wick catheter in fifteen patients with carpal tunnel syndrome and in twelve control subjects, finding that the mean pressure in the carpal canal was elevated significantly in the patients.
Abstract: We measured intracarpal canal pressures with the wick catheter in fifteen patients with carpal tunnel syndrome and in twelve control subjects. The mean pressure in the carpal canal was elevated significantly in the patients. When the wrist was in neutral position, the mean pressure was thirty-two millimeters of mercury. With 90 degrees of wrist flexion the pressure increased to ninety-four millimeters of mercury, while with 90 degrees of wrist extension the mean pressure was 110 millimeters of mercury. The pressure in the control subjects with the wrist in neutral position was 2.5 millimeters of mercury; with wrist flexion the pressure rose to thirty-one millimeters of mercury, and with wrist extension it increased to thirty millimeters of mercury. Carpal tunnel release brought about an immediate and sustained reduction in pressure.
700 citations
TL;DR: Fibrinogen is a soluble plasma protein that is converted to polymeric fibrin in response to damage to the vascular system as discussed by the authors, which forms the matrix of the tangle of cellular and molecular substances called the blood clot.
Abstract: Fibrinogen is a soluble plasma protein that is converted to polymeric fibrin in response to damage to the vascular system. The clotting process is initiated when platelets aggregate at the wound site. Their disruption releases biologically active amines and a proteolytic cascade follows which culminates in the conversion of fibrinogen to fibrin. The fibrin polymer forms the matrix of the tangle of cellular and molecular substances called the blood clot. Atomic-level details are now in hand for many of the interactions that hold fibrin units together, although some aspects have yet to be resolved. Of necessity, fibrin clots need to be dismantled when they are no longer needed, an operation largely accomplished by the proteolytic enzyme plasmin. Various regulatory phenomena are involved in maintaining the balance between intravascular fluidity and clots that prevent blood loss. A variety of hereditary conditions, including mutant fibrinogens, can predispose individuals to either thrombosis or bleeding.
Key concepts:
The underlying fabric of blood clots is a protein polymer called fibrin.
Fibrin clots are formed in response to injuries to any part of the vascular system.
The conversion of soluble fibrinogen molecules to insoluble fibrin depends on thrombin generated from prothrombin.
Keywords:
fibrinogen;
fibrin;
clot stabilisation;
fibrinolysis;
blood clotting;
X-ray structures
597 citations
TL;DR: It is indicated that pain scale preference does not influence pain intensity report, but there are some clinical situations in which a numeric scale is likely to yield a better measure of pain intensity.
Abstract: Chronic pain patients reported pain intensity on each of 3 pain intensity scales, the visual analog, numerical and adjectival scales, and then ranked the scales in order of perceived best communication of pain intensity. All patients were able to complete an adjectival scale but 11% were unable to complete a visual analog scale and 2% failed at a numeric scale. The intensity of the pain ratings on the 3 scales were significantly correlated and there were no reliable differences in reported intensity as a function of preference. Pain intensity was reliably higher on each scale for depressed-anxious patients as compared to non-depressed/non-anxious patients. Patients completing all 3 scales indicated a significant preference for the adjectival scale but the basis for this preference did not appear related to sex, etiology of pain, affective variables nor selected psychological variables. These data indicate that pain scale preference does not influence pain intensity report. Nevertheless, there are some clinical situations in which a numeric scale is likely to yield a better measure of pain intensity.
566 citations
TL;DR: The experimental replacement of calcite and aragonite by dolomite under a variety of conditions indicates that dolmitization can take place in marine and lacustrine environments under two conditions: low dissolved sulfate concentrations and insubstantial contemporary silica diagenesis.
Abstract: The experimental replacement of calcite and aragonite by dolomite under a variety of conditions indicates that dolomitization can take place in marine and lacustrine environments under two conditions: (i) low dissolved sulfate concentrations and (ii) insubstantial contemporaneous silica diagenesis. Common sites for dolomite formation are areas where the dissolved sulfate concentration is reduced by microbial sulfate reduction, through the mixing of seawater with large amounts of fresh water, or where low-sulfate alkaline lacustrine environments prevail. Even under these conditions, dolomite formation may be inhibited by the concurrent transformation of opal-A (amorphous silica) to opal-CT (disordered cristobalite and tridymite), whereas the subsequent transformation of opal-CT to quartz favors the formation of dolomite.
559 citations
TL;DR: The modification of vinculin by p60src may be responsible in part for the disruption of the microfilament organization and for the changes in cell shape and adhesiveness which accompany transformation by Rous sarcoma virus.
534 citations
TL;DR: In this paper, a general discussion of the free-electron lasers (FEL's) with variable parameter wigglers is presented with a view towards their potential for the production of high power optical radiation at reasonable efficiency.
Abstract: A general discussion of the free-electron lasers (FEL's) with variable parameter wigglers is presented with a view towards their potential for the production of high power optical radiation at reasonable efficiency. The theoretical analysis is based upon a one-dimensional relativistic Hamiltonian formulation and is developed in a manner to take advantage of the analogy between the FEL process and radio frequency accelerators. Three promising operational modes are identified and analyzed. The first may be thought of as an electron decelerator and is thought to have the most promise for single-pass devices. Both oscillator and amplifier configurations are studied. The second is based upon adiabatic trapping and detrapping, intended to reduce the spread in electron energy typically induced by the FEL process. The third is based upon the method of phase area displacement. It has the advantage of wide gain bandwidth and small induced energy spread, and is thought to have the most promise for storage ring applications. Generally speaking, it is found that high peak power is intrinsic to these modes of operation. Potential problems from parasitic oscillations analogous to the stimulated Raman effect are analyzed, and some others arising from transverse inhomogeneity are identified.
530 citations
TL;DR: The nucleotide sequences of 15 clones constructed from these 300 nucleotide S 1 -resistant repeats are determined and ten of these cloned sequences are members of the Alu family of interspersed repeats, a dimeric structure that was evidently formed from a head to tail duplication of an ancestral monomeric sequence.
TL;DR: Treatment with high doses of GnRH and its agonists had been predicted to be a potential means for enhancing fertility and, paradoxically, long term administration of these peptides results in sustained increases in serum gonadotropins.
Abstract: Harris (1) first proposed that the anterior pituitary gland is controlled by hypothalamic releasing factors. After the subsequent purification and sequencing of gonadotropin-releasing hormone (GnRH) (2, 3) and the synthesis of potent GnRH agonists and antagonists (4, 5), many laboratories have investigated the effects of these peptides on various reproductive functions. In both males and females, administration of GnRH or its potent agonists results in sustained increases in serum gonadotropins. In women, administration of GnRH causes preovulatory-like surges of gonadotropins (6, 7). In several animal species, a single injection of GnRH induces preovulatory- like surges of LH that trigger ovulation (8–11). Since pituitary gonadotropins are essential for normal gonadal functions and hypothalamic GnRH was believed to act solely on the pituitary gland, treatment with high doses of GnRH and its agonists had been predicted to be a potential means for enhancing fertility. Paradoxically, long term administration...
TL;DR: Since monobromobimane has little fluorescence and reacts very selectively with thiols to produce fluorescent derivatives, crude extracts can be derivatized and analyzed without prepurification of the thiolS, the entire process requiring only 1 to 2 h.
TL;DR: In this paper, a single-factor multivariate time series model is proposed to estimate the unobserved metropolitan wage rate for Los Angeles, based on observations of sectoral wages within the Standard Metropolitan Statistical Area.
Abstract: The paper formulates and estimates a single-factor multivariate time series model. The model is a dynamic generalization of the multiple indicator (or factor analysis) model. It is shown to be a special case of the general state space model and can be estimated by maximum likelihood methods using the Kalman filter algorithm. The model is used to obtain estimates of the unobserved metropolitan wage rate for Los Angeles, based on observations of sectoral wages within the Standard Metropolitan Statistical Area. Hypothesis tests, model diagnostics, and out-of-sample forecasts are used to evaluate the model.
TL;DR: Trophosome tissue of the hydrothermal vent tube worm, Riftia pachyptila (Vestimentifera), contains high activities of several enzymes associated with chemoautotrophic existence, consistent with an autotrophic mode of nutrition for this worm, which lives in hydrogen sulfide-rich waters and lacks a mouth and digestive system.
Abstract: Trophosome tissue of the hydrothermal vent tube worm, Riftia pachyptila (Vestimentifera), contains high activities of several enzymes associated with chemoautotrophic existence. Enzymes catalyzing synthesis of adenosine triphosphate using energy contained in sulfur compounds such as hydrogen sulfide, and two diagnostic enzymes of the Calvin-Benson cycle of carbon dioxide fixation, ribulosebisphosphate carboxylase and ribulose 5-phosphate kinase, are present at high levels in trophosome, but are absent in muscle. These data are consistent with an autotrophic mode of nutrition for this worm, which lives in hydrogen sulfide-rich waters and lacks a mouth and digestive system.
TL;DR: EGF treatment of A431 human epidermoid carcinoma cells is demonstrated to increase phosphotyrosine content, indicating that EGF stimulates tyro sine-specific protein kinase activity in vivo as well as in vitro.
Abstract: Epidermal growth factor (EGF), which binds to specific high-affinity cell-surface receptors, stimulates replication of a number of cell types1,2. In vitro EGF stimulates a membrane-associated protein kinase which catalyses phosphorylation of the EGF receptor at tyrosine residues3,4. The transforming proteins of several RNA tumour viruses are protein kinases which also specifically catalyse phosphorylation at tyrosine residues5–10. An elevated level of phosphotyrosine is found in cells transformed by Rous sarcoma, Fujinami sarcoma, PRCII, Y73, Snyder–Theilin and Gardner–Armstrong feline sarcoma and Abelson murine leukaemia viruses5,10–12. At least four of these viruses, which encode distinct protein kinases, catalyse phosphorylation of tyrosine residues in the same cellular substrate proteins13. In vitro EGF-stimulated protein kinase catalyses the phosphorylation of anti-p60src heavy chains, suggesting that this enzyme recognizes similar substrate determinants to p60src (refs 14,15). Here we demonstrate that EGF treatment of A431 human epidermoid carcinoma cells increases phosphotyrosine content, indicating that EGF stimulates tyro sine-specific protein kinase activity in vivo as well as in vitro. In contrast to Rous sarcoma virus (RSV) transformation, EGF inhibits replication of A431 cells. This inhibition by EGF is influenced by both cell density and tissue culture substratum.
TL;DR: In this paper, the authors concluded that the most prominent layering in the crust is not compositional but metamorphic, and that the continental crust is characterized by lateral and vertical heterogeneities of varying scale which are the apparent cause of the complex seismic reflections recorded by COCORP.
TL;DR: It is argued that there are at least 12 issues that should comprise the study of cognition, and thereby, the field of Cognitive Science, and there need to be a wide variety of behavior before the authors can hope to understand a single class.
TL;DR: All the vestimentiferan worms and several of the molluscs were found to contain enzyme activities associated with sulphide oxidation, the Calvin-Benson cycle and nitrate reduction, suggesting that the putative animal-bacterial symbiosis first described in Riftia pachyptila may be of widespread occurrence in species living in environments offering simultaneous access to sulphide and oxygen.
Abstract: The role of sulphide oxidation-driven production of reduced carbon in the nutrition of animals adapted to life in sulphide-rich habitats such as the deep-sea hydrothermal vents and intertidal mudflats has been a topic of recent interest1–4. Chemoautotrophic sulphide-oxidizing bacteria have been isolated from samples of sulphide-rich vent water5–8, and it has been suggested that these could provide a food source for filter-feeding animals that live at the vents. The recent discovery of prokaryotic cells9 and activities of sulphide-oxidizing enzymes (which generate reducing power and ATP) and Calvin—Benson cycle enzymes10 within the trophosome tissue of the large vestimentiferan tubeworm of the vents, Riftia pachyptila Jones (Phylum Pogonophora)11 suggests that sulphide-oxidizing chemoauto-trophic bacteria exist in a symbiotic relationship with at least this vent species. This discovery led us to measure enzyme activities associated with sulphide oxidation, the Calvin-Benson cycle and nitrate reduction in a variety of other vestimentiferan tube-worms and bivalve molluscs which occur in sulphide-rich habitats. All the vestimentiferan worms and several of the molluscs were found to contain these enzymatic activities, suggesting that the putative animal-bacterial symbiosis first described in Riftia pachyptila may be of widespread occurrence in species living in environments offering simultaneous access to sulphide and oxygen.
TL;DR: The authors describes a phenomenon which sheds some light on one aspects of the process of combining the meanings of individual words combined to form a more global description of meaning, and explains why people answer "two" even though they know quite well that it was Noah and not Moses who sailed the Ark.
TL;DR: The direct inhibitory effect of glucocorticoids on testicular LH receptor content and steroidogenesis is demonstrated, suggesting the adrenal glucocORTicoids may regulate testis functions.
Abstract: The direct effects of glucocorticoids on testicular LH receptor content and steroidogenesis were studied in vivo and in vitro. Immature hypophysectomized rats were treated with varying doses of dexamethasone, corticosterone, or a synthetic progestin, 17,21-dimethyl-19-nor-pregna-4,9-diene-3,20-dione (R5020). Some animals were also treated concomitantly with FSH to prevent the hypophysectomy-induced decrease in testis functions. At the end of 5 days of treatment, testicular LH/hCG receptor content was measured by [125I]hCG binding assay while steroidogenic responsiveness was measured by in vitro incubation of testes. Dexamethasone decreased testicular LH receptor in control and FSH-treated hypophysectomized rats in doses as low as 10 microgram/day, whereas corticosterone (10 microgram/day) decreased testicular LH receptor in the FSH-treated rats but had no effect in rats not treated with FSH. In contrast, R5020 had no effect on testicular LH receptor content. In vivo treatment of hypophysectomized rats with FSH increased both basal and hCG-stimulated production of androstanediol in vitro. In contrast, concomitant treatment with dexamethasone, but not R5020, decreased both basal and hCG-stimulated testicular androstanediol production. The direct effect of glucocorticoids on testicular steroidogenic potentials was also studied in primary culture of testicular cells obtained from adult hypophysectomized rats. Treatment of cultured testicular cells wtih hCG increased testosterone production. The addition of various natural and synthetic glucocorticoids, but not R5020, to hCG-treated cells decreased testosterone production in a dose- and time-related manner (triamcinolone greater than or equal to dexamethasone greater than cortisol greater than or equal to corticosterone). A 40% decrease in testosterone production was apparent at 6 h after addition of 10(-7) M dexamethasone to hCG-treated cells. These results demonstrate the direct inhibitory effect of glucocorticoids on testicular LH receptor content and steroidogenesis, suggesting the adrenal glucocorticoids may regulate testis functions.
TL;DR: Measurements of total solar irradiance show the irradiance to have been variable throughout the first 153 days of observations, and suggest that considerable energy storage occurs within the convection zone in solar active regions.
Abstract: High-precision measurements of total solar irradiance, made by the active cavity radiometer irradiance monitor on the Solar Maximum Mission satellite, show the irradiance to have been variable throughout the first 153 days of observations. The corrected data resolve orbit-to-orbit variations with uncertainties as small as 0.001 percent. Irradiance fluctuations are typical of a band-limited noise spectrum with high-frequency cutoff near 0.15 day(-1) their amplitudes about the mean value of 1368.31 watts per square meter approach +/- 0.05 percent. Two large decreases in irrradiance of up to 0.2 percent lasting about 1 week are highly correlated with the development of sunspot groups. The magnitude and time scale of the irradiance variability suggest that considerable energy storage occurs within the convection zone in solar active regions.
TL;DR: The findings suggest that the gonadotroph constitutes a target cell of insulin and that insulin may act directly on the anterior pituitary in the regulation of gonadotropin release.
Abstract: The role of insulin in the regulation of basal and gonadotropin-releasing hormone (GnRH)-stimulated release of LH and FSH was investigated in vitro using primary cultures of rat anterior pituitary cells from adult ovariectomized rats. Anterior pituitary cells were incubated for 2 days in the presence or absence of insulin in a serum-free medium. At the end of the insulin treatment, the cells were washed and reincubated in the presence or absence of GnRH, and the LH and FSH released into the medium were measured by RIA. Treatment with insulin (1.0 microgram/ml) for 2 days resulted in significant increases in both the basal and the maximal release of LH and FSH, as well as a 3.2- and 6.3-fold decrease in the ED50 values for GnRH in terms of LH and FSH release, respectively. Treatment with increasing concentrations (0.1-10,000 ng/ml) of insulin, led to a dose-dependent increase in the GnRH (3 X 10(-10) M)-stimulated release of both LH and FSH. This effect of insulin was significant (P less than 0.05) at a physiological concentration of 1 ng/ml (24 microU/ml) with an ED50 value of 40 ng/ml. Increasing duration of exposure to insulin resulted in time-dependent increases in the GnRH (3 X 10(-10) M)-stimulated release of LH, becoming significant at 24 h with maximal enhancement observed by 48 h. The effect of insulin was specific; epidermal or fibroblast growth factor did not enhance LH release. The augmenting effect of insulin was not associated with cellular proliferation or an overall change in protein or LH synthesis. Furthermore, the effect of insulin was independent of the ambient glucose concentration. Insulin was, however, without effect on gonadotrophs cultured in a serum-supplemented medium. Our findings suggest that the gonadotroph constitutes a target cell of insulin and that insulin may act directly on the anterior pituitary in the regulation of gonadotropin release.
TL;DR: The argument is made that in the process of repeated social transmission and use, cultural programs come to take forms which have a good “fit” to the natural capacities and constraints of the human information processing system.
TL;DR: In this paper, the mineralogy of the samples has been determined by X-ray diffractometry, scanning electron microscopy, and Xray energy dispersive analysis from eight active and inactive vent sites along the East Pacific Rise at 21°N during the RISE expedition of April 1979.
TL;DR: Analysis of the process of partial transcription termination (attenuation), which results in nonequimolar synthesis of vesicular stomatitis virus (VSV) mRNAs during sequential transcription, shows that transcription appears to be discontinuous, with significant pauses occurring at or near the intergenic regions.
TL;DR: In this article, the least squares estimator for the parameters of a misspecified nonlinear model was shown to converge strongly to a (weighted) least squares approximation to the true model under general conditions.
Abstract: Under general conditions given here, the least squares estimator for the parameters of a misspecified nonlinear model converge strongly to the parameters of a (weighted) least squares approximation to the true model. With additional conditions, the least squares estimator is asymptotically normal. A new, specification-robust estimator of the covariance matrix is obtained, which simplifies to the usual estimator when the model is correct up to an independent additive error. The properties of the approximation and the covariance estimator are exploited to yield new tests for model misspecification. These results are applied to two examples in economics.
TL;DR: The finding of elevated plasma NE in patients with severe head injury raises the possibility of adverse effects of sympathetic hyperactivity in patients without head injury, including hypermetabolism, cardiovascular abnormalities, and direct effects of catecholamines on the damaged central nervous system.
Abstract: Plasma norepinephrine (NE) and dopamine beta-hydroxylase (DBH) levels were measured during the first 7 days after head injury in 48 patients. Blood pressure, pulse, temperature, and Glasgow coma score (GCS) were recorded at the time of sampling for each patient, and the relationships of these to NE and DBH were examined. In patients with multiple trauma, NE levels were usually elevated, regardless of the GCS. In patients with head injury alone, however, NE was proportional to GCS. Alert patients after a brief loss of consciousness (GCS, 14) had normal NE levels. Those in coma had levels as high as 7 times normal. Blood pressure, pulse, and temperature were found to be elevated proportionally to elevations in plasma NE in patients with head injury. The finding of elevated plasma NE in patients with severe head injury raises the possibility of adverse effects of sympathetic hyperactivity in patients with severe head injury, including hypermetabolism, cardiovascular abnormalities, and direct effects of catecholamines on the damaged central nervous system.
TL;DR: In this paper, a class of globally and quadratically converging algorithms for a system of nonlinear equations,g(u)=0, whereg is a sufficiently smooth homeomorphism, were derived.
Abstract: We derive a class of globally and quadratically converging algorithms for a system of nonlinear equations,g(u)=0, whereg is a sufficiently smooth homeomorphism. Particular attention is directed to key parameters which control the iteration. Several examples are given that have been successful in solving the coupled nonlinear PDEs which arise in semiconductor device modelling.
TL;DR: It was found that the quasi-linear viscoelastic theory can adequately describe the time and history-dependent rheological properties of the canine medial collateral ligament.
Abstract: The viscoelastic properties of the canine medial collateral ligament (MCL) were investigated. Stress-strain relationships at different strain rates, long-term stress relaxation and cyclic stress-strain curves of the MCL were obtained experimentally using a bone-MCL-bone preparation. The experimental data were used in conjunction with the quasi-linear viscoelastic theory as proposed by Fung [15] to characterize the reduced relaxation function, G(t) and elastic response sigma e (epsilon) of this tissue. It was found that the quasi-linear viscoelastic theory can adequately describe the time and history-dependent rheological properties of the canine medial collateral ligament.