Showing papers by "University of California, San Francisco published in 1980"
TL;DR: Bacterial clones containing inserted DNA sequences specific for α- Tubulin, β-tubulin,β-Actin and γ-actin have been constructed from mRNA of embryonic chick brain and are able to hybridize under stringent conditions to DNA of all vertebrates tested, as well as to sea urchin DNA, but not to yeast DNA.
1,650 citations
TL;DR: Eighty cases were identified in which the patient was given a single course of radiation therapy and in which reasonable estimates of the time-dose-fractionation regimen could be made, and total dose, overall treatment time and number of treatment fractions were analyzed.
Abstract: This is a review and reanalysis of the literature on adverse effects of therapeutic irradiation on the brain. Reactions have been grouped and considered according to time of appearance. The emphasis of the analysis is on delayed reactions, especially those that occur from a few months to several years after irradiation. Over 100 such cases are reported in the literature. Eighty cases were identified in which the patient was given a single course of radiation therapy and in which reasonable estimates of the time-dose-fractionation regimen could be made. Eleven of these patients had been irradiated for cancer of the skin, 17 for other extracranial tumors, 20 for either a pituitary tumor or a craniopharyngioma and 32 for primary brain tumors. All dose specifications were converted into equivalent megavoltage rads. The data were analyzed in terms of total dose, overall treatment time and number of treatment fractions. The data were also analyzed in terms of time-dose-fractionation (TDF) and nominal standard dose (NSD). NSD calculations were done according to the usual Ellis formula and also according to a modification in which the N exponent was −0.44 and the T exponent −0.06. When total dose was plotted against number of fractions, a line with slope 0.44 fitted well with the lower dose limits at which brain necrosis has been reported. Also discussed were acute radiation reactions, early delayed radiation reactions, somnolence and leukoencephalopathy post-irradiation/chemotherapy and combined effects of radiation and chemotherapy.
929 citations
779 citations
TL;DR: The availability of stem cell lines isolated from mouse teratocarcinomas has made possible a number of new biochemical, immunological, and genetic approahes to the study of early mammalian development.
Abstract: In the last decade there has emerged an appreciation of the remarkable similarity between the cells that give rise to teratocarcinomas in mice and the cells that give rise to the developing mouse embryo. The resemblance is so close that in certain instances the tumor stem cells can join with their embryonic counterparts and develop into a completely normal mouse. The availability of stem cell lines isolated from mouse teratocarcinomas has made possible a number of new biochemical, immunological, and genetic approahes to the study of early mammalian development.
730 citations
TL;DR: An important role for vitamin D in the endocrine functioning of the pancreas is indicated by the previously demonstrated presence of a vitamin D-dependent calcium-binding protein and cytosol receptor for the hormonal form of vitamin D, 1,25-dihydroxyvitamin D3.
Abstract: The effects of a vitamin D deficiency on insulin and glucagon release was determined in the isolated perfused rat pancreas by radioimmunoassay of the secreted proteins. During a 30-minute period of perfusion with glucose and arginine, pancreases from vitamin D-deficient rats exhibited a 48 percent reduction in insulin secretion compared to that for pancreases from vitamin D-deficient rats that had been replenished with vitamin D. Vitamin D status had no effect on pancreatic glucagon secretion. This result, along with the previously demonstrated presence in the pancreas of a vitamin D-dependent calcium-binding protein and cytosol receptor for the hormonal form of vitamin D, 1,25-dihydroxyvitamin D3, indicates an important role for vitamin D in the endocrine functioning of the pancreas.
709 citations
565 citations
TL;DR: A comparison of the human with the rat insulin genes indicates potential regulatory regions in the DNA segment preceding the gene and suggests that the ancestral form of the insulin gene had two intervening sequences.
Abstract: The human insulin gene contains two intervening sequences, one is within the region transcribed into the 5'-untranslated segment of the mRNA and the other interrupts the C-peptide encoding region. A comparison of the human with the rat insulin genes indicates potential regulatory regions in the DNA segment preceding the gene and suggests that the ancestral form of the insulin gene had two intervening sequences.
533 citations
TL;DR: The appropriate use of a logarithmic trapezoidal equation for calculating the area under the moments curve (AUMC) is shown to increase the accuracy of estimating MDT.
Abstract: Moments analysis has been applied to the calculation of mean (in vivo)dissolution time (MDT) and mean absorption time (MAT) from plasma level of drug versus time data. Methods for accurately estimating the MDT under varying conditions, limitations of the methods, and interpretation of the data are presented. The importance of accurate estimates of the terminal rate constant (λz) and the drug concentration at the time of withdrawing the final plasma sample (Ĉz)is emphasized in connection with extrapolation to t=∞.The appropriate use of a logarithmic trapezoidal equation for calculating the area under the moments curve (AUMC) is shown to increase the accuracy of estimating MDT.
528 citations
TL;DR: It is demonstrated that the T4 DNA topoisomerase changes the linking number of a covalently closed double-stranded circular DNA molecule only by multiples of two, which indicates that this enzyme must act via mechanisms that involve the concerted cleavage and rejoining of two opposite DNA strands, such that the DNA double helix is transiently broken.
512 citations
TL;DR: In this paper, a data set consisting of 124 steadystate phenytoin concentration-dosage pairs from 49 patients, obtained in the routine course of their therapy, was analyzed by each method.
Abstract: Individual pharmacokinetic parameters quantify the pharmacokinetics of an individual, while population pharmacokinetic parameters quantify population mean kinetics, interindividual variability, and residual intraindividual variability plus measurement error. Individual pharmacokinetics are estimated by fitting individual data to a pharmacokinetic model. Population pharmacokinetic parameters are estimated either by fitting all individual's data together as though there were no individual kinetic differences (the naive pooled data approach), or by fitting each individual's data separately, and then combining the individual parameter estimates (the two-stage approach). A third approach, NONMEM, takes a middle course between these, and avoids shortcomings of each of them. A data set consisting of 124 steady-state phenytoin concentration-dosage pairs from 49 patients, obtained in the routine course of their therapy, was analyzed by each method. The resulting population parameter estimates differ considerably (population mean Km, for example, is estimated as 1.57, 5.36, and 4.44 μg/ml by the naive pooled data, two-stage, and NONMEM approaches, respectively). Simulations of the data were analyzed to investigate these differences. The simulations indicate that the pooled data approach fails to estimate variabilities and produces imprecise estimates of mean kinetics. The two-stage appproach produces good estimates of mean kinetics, but biased and imprecise estimates of interindividual variability. NONMEM produces accurate and precise estimates of all parameters, and also reasonable confidence intervals for them. This performance is exactly what is expected from theoretical considerations and provides empirical support for the use of NONMEM when estimating population pharmacokinetics from routine type patient data.
505 citations
TL;DR: The procedure is relatively simple, rapid, and yields almost quantitative recovery of vesicles that encapsulate a large percentage of the total aqueous space.
TL;DR: Binding was saturable, reversible, of high affinity, and was inhibited by cholecystokinin analogs but not by unrelated hormones.
Abstract: Specific cholecystokinin binding sites in particulate fractions of rat brain were measured with iodine 125-labeled Bolton-Hunter cholecystokinin, a cholecystokinin analog that has full biological activity. Binding was detected in brain regions known to contain immunoreactive cholecystokinin. Binding was saturable, reversible, of high affinity (dissociation constant, 1.7 x 10(-9) M), and was inhibited by cholecystokinin analogs but not by unrelated hormones.
TL;DR: The current data indicate that under the influence of pharmacologic doses of estradiol the liver of the rat contains increased amounts of a functional lipoprotein receptor that binds lipoproteins containing apolipoproteins B and E.
TL;DR: The afterhyperpolarization produced in the presence of y-aminobutyric acid antagonists is associated with a conductance increase and is inhibitory and has implications for understanding the cellular mechanisms of epilepsy.
Abstract: Synaptic excitation of hippocampal cells during blockade of synaptic inhibition results in an epileptiform "burst" potential followed by a prolonged afterhyperpolarization. This afterhyperpolarization resembles the one that is seen after the epileptic interictal spike and that is considered of critical importance in preventing seizure development. The afterhyperpolarization produced in the presence of y-aminobutyric acid antagonists is associated with a conductance increase and is inhibitory. It can occur in an all-or-none fashion after a burst, is independent of chloride, and is depressed by barium. The afterhyperpolarization has a reversal potential of (-86) millivolts, and the reversal potential is strongly dependent on the extracellular concentration of potassium. The afterhyperpolarization appears to be an intrinsic, inhibitory potassium potential mediated by calcium. This finding has implications for understanding the cellular mechanisms of epilepsy.
TL;DR: The luminal and antiluminal membranes of brain capillaries are biochemically and functionally different and this polarity should permit active solute transport across brain capillary endothelial cells which are the cells responsible for the blood-brain barrier.
TL;DR: This model provides, in addition, for the continuous renewal of outer‐segment plasma membrane and establishes a developmental basis for the structural uniqueness of the disc rim, and indicates an evolutionary relationship between the discs of vertebrate visual cells and the membrane specializations of invertebrates visual cells.
Abstract: Electron microscopic examination of the bases of adult rod and cone outer segments (rhesus monkey, ground squirrel, and grey squirrel) has led to a new model of disc morphogenesis. In this model the disc surfaces and disc rims develop by separate mechanisms and from separate regions of the membrane of the inner face of the cilium. This membrane is alternately specified into regions that will form either the disc surfaces or the disc rims. The disc surfaces develop by an evagination or outpouching of the ciliary membrane. The two surfaces of an evagination, scleral and vitreal, each form one of the surfaces of adjacent discs. The disc rim is initially specified as a region of ciliary membrane between adjacent disc-surface evaginations. This region grows bilaterally around the circumferences of adjacent discs, zippering together the apposed surfaces to form the rim and completed disc. At the same time it seals the plasma-membrane edges of the evaginations, which have become detached from the surfaces. Incisures form in rod discs by infolding of the rim and surfaces together, and they begin to form before the rim is completed around the disc perimeter. When a number of new discs are developing simultaneously the ciliary membrane at the base of an outer segment consists of a stack of rim forming and surface forming growth points. This model provides, in addition, for the continuous renewal of outer-segment plasma membrane. It also establishes a developmental basis for the structural uniqueness of the disc rim. Finally, it indicates an evolutionary relationship between the discs of vertebrate visual cells and the membrane specializations of invertebrate visual cells.
TL;DR: The hybridization method detected the presence of enterotoxigenic E. coli in bacterial growth in directly spotted stools from patients with acute diarrhea and suggested that the LTs produced by different isolates of E. Escherichia coli are homologous.
Abstract: A method fo detecting large numbers of isolates of enterotoxigenic Escherichia coli is described in which the genes encoding th enterotoxins are detected, rather than the toxins themselves. Radiolabeled fragments of DNA encoding the heat-labile (LT) or heat-stable (ST) toxins were used as hybridization probes for homologous DNA sequences in E. coli colonies grown and lysed in situ on nitrocellulose filters. The LT probe detected all of 31 E. coli strains producing ST and LT or only LT, while the ST probe detected 12 of 17 strains producing only ST and three of 26 strains producing ST and LT. These results suggest that the LTs produced by different isolates of E. coli are homologous and that human isolates of E. coli produce at least two heterologous STs detectable in the infant mouse assay. The hybridization method also detected the presence of enterotoxigenic E. coli in bacterial growth in directly spotted stools from patients with acute diarrhea.
TL;DR: Increased ornithine decarboxylase activity, with the resultant increase in polyamine content, may play an essential role in intestinal mucosal maturation and regeneration in the rat.
Abstract: A transient increase in ornithine decarboxylase activity and polyamine biosynthesis occurs in the intestinal mucosa of the newborn rat in the third week after birth. During this period, there is a rapid conversion of the mucosa from a fetal to a mature adult status. A similar increase in ornithine decarboxylase activity also accompanies the rapid recovery of the mucosa 1 week after an injury is induced by chemotherapy in adult rats. In vivo, alpha-difluoromethyl ornithine, a highly selective, enzyme-activated, irreversible inhibitor, suppresses these increases in mucosal ornithine decarboxylase and delays both intestinal mucosal maturation and recovery from injury. Thus increased ornithine decarboxylase activity, with the resultant increase in polyamine content, may play an essential role in intestinal mucosal maturation and regeneration in the rat.
TL;DR: A prospective collaborative study was conducted in five centers during a 13-year period to identify factors that influence the development of visual-field defects (GVFDs) of open angle glaucoma, and found their collective predictive power to be undesirably poor.
Abstract: • A prospective collaborative study was conducted in five centers during a 13-year period to identify factors that influence the development of visual-field defects (GVFDs) of open angle glaucoma. In 5,000 subjects, GVFDs developed in only 1.7% of eyes. Statistical analysis of 26 factors at first examination identified five that were significantly related to the development of GVFDs—outflow facility, age, applanation pressure, cup-disc ratio, and pressure change after water drinking. Their absolute initial value, and not its change with time, was the important predictor. Multivariate analysis showed their collective predictive power to be undesirably poor, indicating that other factors must play an important role in the development of GVFDs. Mortality-table analysis indicated that during a period of five years, 98.54% of eyes with initial pressure less than 20 mm Hg continued to be free from GVFDs as compared with 93.34% of those with pressure 20 mm Hg or greater.
TL;DR: It appears that a variety of treatments, namely, chelating drugs, transition series metals, sulfhydryl reagents, heat shock, and amino acid analogous can induced similar, if not identical, proteins in eukaryotic cells.
TL;DR: Inhibition of inhibitory interneurones may be primary targets for opioid peptide-containing pathways and disinhibition may be of general importance for opium peptide action in the CNS.
Abstract: Enkephalin markedly attenuates a variety of GABAergic inhibitory pathways in the CNS, but does not affect the action of GABA. The action of enkephalin is reversed by the specific opiate antagonist, naloxone. Thus, inhibitory interneurones may be primary targets for opioid peptide-containing pathways and disinhibition may be of general importance for opioid peptide action in the CNS.
TL;DR: Both tumor cells and normal cells of epithelial origin are more likely to resemble their in vivo counterparts when maintained on extracellular matrix than on plastic, and when so maintained can therefore provide a better model for oncogenic studies.
TL;DR: Homologies in the amino acid sequences of the two peptides outside the somatostatin moiety suggest other regions of the molecules have biological functions.
Abstract: Complementary DNAs for two distinct anglerfish somatostatin peptides (termed I and II) have been cloned in bacterial plasmids and sequenced. The nucleotide sequence for somatostatin I encodes a large precursor peptide (molecular weight 13,300) in which the somatostatin hormone is at the carboxyl terminus. The predicted 14-amino acid sequence for anglerfish somatostatin I is the same as mammalian somatostatin. Somatostatin II is also synthesized as part of a larger precursor (molecular weight 14,100) with the presumptive somatostatin hormone also at the carboxyl terminus. The 14-amino acid sequence of somatostatin II differs from somatostatin I at two internal residues (Tyr in place ofPhe 7 and Gly in place of Thr 10). The two different somatostatins may have distinct biological activities. Homologies in the amino acid sequences of the two peptides outside the somatostatin moiety suggest other regions of the molecules have biological functions.
TL;DR: A segment of a DNA encoding most of POMC is isolated, using as probe a mouse 144-base pair cloned cDNA fragment encoding β-MSH and β-endorphin, and this may indicate an as yet unrecognized biological function(s) for the NH2-terminal portion of the 16K fragment.
Abstract: The peptide hormones ACTH, beta-endorphin, alpha- and beta-melanotropin(MSH) and possibly gamma-MSH are synthesized in the pituitary gland by the processing of a 32,000-molecular weight (MW) polypeptide called proopiomelanocortin (POMC) The existence of a further precursor (pre form) to POMC containing an additional N-terminal 'leader' peptide has been suggested by analysis of the in vitro translation products of poly(A)-containing RNA from AtT-20 cells, a mouse ACTH-producing cell line of pituitary origin Nakanishi et al cloned and sequenced a cDNA copy of the bovine prePOMC mRNA This sequence confirmed the known structure of the carboxyl half of POMC and revealed the presence of a new MSH-like moiety, gamma-MSH, within the 16,000-MW amino half of the precursor (16K fragment) Recent experiments have suggested that this peptide may act in synergy with ACTH to increase corticosterone and aldosterone production in vivo and in vitro We have now isolated from a rat genomic DNA library a segment of a DNA encoding most of POMC, using as probe a mouse 144-base pair cloned cDNA fragment encoding beta-MSH and beta-endorphin The cloned rat gene is one of two (or more) closely related POMC genes The DNA sequence obtained shows that the cloned POMC gene is not interrupted by any intervening sequence (IVS) between the codon for amino acid 19 and the presumptive poly(A) addition site This region of POMC encodes all the biologically active peptides mentioned above The DNA sequence encoding the putative gamma-MSH and the coding sequence that precedes it are highly conserved between rat and cow This may indicate an as yet unrecognized biological function(s) for the NH2-terminal portion of the 16K fragment
TL;DR: Results demonstrate that the cloned DNA molecules are functionally identical to viral DNA produced in vivo; therefore, molecular cloning did not cause any major alterations of the DNA.
Abstract: Supercoiled DNA molecules were used for the molecular cloning of full-length avian sarcoma virus (ASV) DNA. Viral DNA produced by the Schmidt-Ruppin A (SR-A) strain of ASV was isolated from acutely infected transformed quail cells. Supercoiled DNA was separated from linear and open circular DNA by acid phenol extraction, opened into a full-length linear form by cleavage with the restriction endonuclease SacI, and cloned into lambda gtWES x lambda B. Four different cloned viral DNA molecules were isolated: SRA-1 contains two copies of the 330-base pair terminal redundancy normally found at each end of the linear DNA molecules, but harbors a 63-base pair deletion that spans the site at which the two copies of the terminal redundancy are joined in circular DNA molecules; SRA-2 contains two complete copies of the terminal redundancy; SRA-3 probably contains only one copy of the terminal redundancy but in all other respects appears to be similar to SRA-2; SRA-4 contains a 2,500-base pair deletion that removes all of the src gene (the gene responsible for transformation by ASVs) plus additional nucleotides adjacent to the src gene whose precise locations have not been determined. Transfection of chicken embryo fibroblasts by either SRA-1 or SRA-2 resulted both in the appearance of transformed cells and in the production of infectious virus. These results demonstrate that the cloned DNA molecules are functionally identical to viral DNA produced in vivo; therefore, molecular cloning did not cause any major alterations of the DNA. The infectivity of SRA-1 DNA indicates that the 63 base pairs missing from that molecule are not required for the initiation of viral RNA synthesis, even though the deletion is located in a copy of the terminal redundancy thought to carry a promoter for RNA synthesis. This suggests that the deletion does not remove any sequences required for the initiation of transcription.
01 Jan 1980
TL;DR: The complete sequence (3221 nucleotides) of the hepatitis B viral DNA (adw2 serotype) is reported and a single segment capable of coding a peptide of 94 amino acids is identified.
Abstract: The complete sequence (3221 nucleotides) of the hepatitis B viral DNA (adw2 serotype) is reported. The long strand has four major polypeptide coding regions with an aggregate translational capacity of 1613 amino acids (4839 nucleotides). Two genes coding for the major viral proteins have been identified; the previously described surface antigen gene coding for a protein of 25, 398 daltons and the core antigen gene, which codes for a basic polypeptide (21, 335 daltons) with a striking protamine-like sequence at its C-terminus. There are two other putative peptide coding regions: A, which overlaps the surface antigen gene and may code for a protein up to about 95,000 daltons and B, which partially overlaps the core gene and may code for a peptide of about 16,000 daltons. The short strand of the virus is largely devoid of possible peptide coding regions. A single segment capable of coding a peptide of 94 amino acids is identified.
TL;DR: It appears that a single viral protein is responsible for both the initiation and maintenance of neoplastic transformation by avian sarcoma virus.
Abstract: The transforming gene (src) of avian sarcoma virus (ASV) and adjacent regions of the viral genome have been isolated by molelcular cloning of viral DNA. Their nucleotide sequence encompasses the whole of src and the portion of the gene env that encodes gp 37, one of two glycoproteins found in the viral envelope. Src encodes a single, hydrophobic protein with structural features that conform to previous descriptions descriptions of the gene product (pp60src). It appears that a single viral protein is responsible for both the initiation and maintenance of neoplastic transformation by avian sarcoma virus. Neither src nor its product bear any obvious structural relationship to several other viral oncogenes and their encoded proteins. Src is flanked by a repeated nucleotide sequence that may facilitate frequent deletion of the gene from the viral genome.
TL;DR: A model for the production of sister-chromatid exchanges is presented, based on the idea that double-strand breaks are generated at junctions between a completely duplicated replicon cluster and a partially duplicated Replicon cluster.
Abstract: A model for the production of sister-chromatid exchanges is presented, based on the idea that double-strand breaks are generated at junctions between a completely duplicated replicon cluster and a partially duplicated replicon cluster. Agents that induce absolute blocks to DNA fork displacement will cause this condition to persist longer than normal, whereas agents that inhibit initiation of whole clusters will rarely cause it at all. During the blunt-end repair of the double-strand breaks, sister-chromatid exchange would be initiated when daughter strands of a duplicated cluster recombine with the parental strands of the partially replicated cluster. When the latter finishes replication, sister-chromatid exchange would be completed.
TL;DR: The spatial distribution of neurons with different binaural response properties has been studied within the three dimensions of the primary auditory cortex (AI) in the cat and the implications for the concept of AI as a unitary element in auditory processing are discussed.
TL;DR: This research attacked the mode of action of central nervous system injury by attacking the “spatially aggregating” regions of the nervous system, which are responsible for feelings of pain and tremor.