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At least 1,243 records · Page 69Linked to original sources
PubMed1978

Staphylococcal nuclease reviewed: a prototypic study in contemporary enzymology. I. Isolation; physical and enzymatic properties.

This is the first of a series of four articles in which the chemical, enzymological, and crystallographic work on Ribonucleate (deoxyribonucleate)-3'-nucleotidohydrolase, EC 3.1.4.7, (Staphylococcal nuclease, Micrococcal nuclease) will be reviewed and correlated. This article discusses the purification of the enzyme and its general physical and enzymological properties. Subsequent articles will deal with specific studies of the nucleotide binding site, crystallographic studies of a nuclease-inhibitor complex, use of the nuclease as a model for protein folding and possible mechanisms for the action of the enzyme.

Amino Acid Sequence↗
PubMed1994

Binding of carbohydrates to solid supports: evaluation of a prototype system.

Mono- and disaccharides were covalently and irreversibly bound to aminopolystyrene beads in good yield by heating in dilute aqueous solution. The degree and stability of sugar binding were determined by chemical and radiochemical methods and the accessibility of the bound sugars was demonstrated by exoglycosidase hydrolysis and by an enzyme-linked lectin-binding assay using Concanavalin A.

Chromatography↗
PubMed1982

A prototype generalized network technology for hospitals: initial implementation.

A demonstration implementation of a distributed data-processing hospital information system using an intelligent local area communications network (LACN) technology is described. This system is operational at the UCSF Medical Center and integrates four heterogeneous, stand-alone minicomputers. The applications systems are PID/Registration, Outpatient Pharmacy, Clinical Laboratory, and Radiology/Medical Records. Functional autonomy of these systems has been maintained, and no operating system changes have been required. The LACN uses a fiber-optic communications medium and provides extensive communications protocol support within the network, based on the ISO/OSI Model. The architecture is reconfigurable and expandable. This paper describes system architectural issues, the applications environment, and the local area network.

California↗
PubMed1995

Papain-like proteinase of turnip yellow mosaic virus: a prototype of a new viral proteinase group.

Sequence comparisons predicted a potential papain-like proteinase domain in the N-terminal cleavage product (NRP) of the large nonstructural replicase polyprotein (RP) of turnip yellow mosaic virus (TYMV). Replacement of the predicted catalytic amino acids, Cys-783 by Ser, or of His-869 by Glu, abolished cleavage of the 206K RP into a approximately 150 K NRP and a approximately 78 K C-terminal product in reticulocyte lysates, while other substitutions exerted no apparent influence on proteolysis. The proteinase-deficient mutant RPs could not be cleaved in trans by as much as an eight-fold molar excess of wild-type proteinase. Deletion experiments have excluded the possible influence on autoproteolysis of amino acid sequences 1-708 and 982-1204 flanking the proteinase domain. Thus, the proteinase of TYMV with a papain-like dyad of essential amino acids has been mapped just upstream from the putative NTPase domain. Statistically significant sequence similarities with the TYMV proteinase were found for the similarly located domains of the replicase polyproteins of carlaviruses, capilloviruses, apple stem pitting virus and apple chlorotic leaf spot virus as well as for those of other tymoviruses and for the domain located downstream from the putative NTPase domain of the large polyprotein of beet necrotic yellow vein furovirus. All these domains are not significantly similar to other known proteinases, although they conserve papain-like Cys- and His-containing motifs. Thus these domains constitute a compact group of related enzymes, the tymo-like proteinases, within the proposed papain-like proteinase supergroup. The resulting alignment of 10 tymo-like proteinase sequences has revealed a third highly conserved residue--Gly (Gly821 in TYMV RP) followed by a hydrophobic residue. We speculate that all the tymo-like proteinase domains of the viral replicative proteins may share common biochemical and biological features.

Amino Acid Sequence↗
PubMed1978

Virulence and persistence of three prototype strains of mumps virus in newborn hamsters.

Neuroadapted mumps virus (NMV) produces widespread central nervous system (CNS) disease and death after intracerebral (i.c.) inoculation of newborn hamsters. After intraperitoneal (i.p.) inoculation, NMV causes disseminated disease, moderate mortality and it persists in CNS tissues. Low tissue culture passage isolates of wild mumps virus do not establish CNS infection after i.p. inoculation; after i.c. inoculation they cause limited though persistent infection with little acute mortality. The biological behavior of a highly passaged vaccine strain of mumps virus (Jeryl-Lynn) is more similar to NMV than to the wild strain in its behavior in the newborn hamster.

Adaptation, Biological↗
PubMed1993

Comparative analysis of the NS 1 gene sequences of dengue-1 viruses prototype Hawaii strain and Thai isolate TH-Sman, and determination of the intratypic variation of NS 1 protein among dengue-1 viruses.

In view of a previous report on significant antigenic and biophysical differences between the purified soluble complement-fixing antigens of dengue-1 virus strains Hawaii and TH-Sman, the NS 1 genes of both virus isolates were cloned, sequenced, and compared in an attempt to define the genetic basis for the observed differences. Sequence comparison revealed ten encoded amino acid differences between the NS 1 genes of both viruses. Three of these amino acid differences, which are associated with a change in charge distribution, are clustered within the major antigenic region previously defined by studies of recombinant dengue-1 NS 1 protein expressed in E. coli. In parallel, the NS 1 sequences of both Hawaii and TH-Sman isolates were also aligned and compared with two other published dengue-1 NS 1 protein sequences to determine the intratypic variation of dengue-1 NS 1 antigen. Pairwise comparisons between the encoded amino acid sequences revealed a variability of 1.1% to 3.1% difference in the NS 1 protein among dengue-1 strains, which is comparable to that reported for dengue-1 envelope protein (0.2% to 3.6% difference) but less than that of dengue-2 NS 1 protein (0.6% to 7.4% difference).

Amino Acid Sequence↗
PubMed1989

Prototype ventilator and alarm algorithm for the NASA space station.

An alarm algorithm was developed to monitor the ventilator on the National Aeronautics and Space Administration space station. The algorithm automatically identifies and interprets critical events so that an untrained user can manage the mechanical ventilation of a critically injured crew member. The algorithm was tested in two healthy volunteers by simulating 260 critical events in each volunteer while the volunteer breathed via the ventilator. Thirteen critical events were induced eight times in random order, for the five different modes of ventilation. These events included various ventilator tubing disconnects, leaks, and occlusions, as well as power and gas supply failures. The algorithm identified the critical events and generated alarms in response to 99.2% (516 of 520, total) of the events. The alarm textual messages were correct 98% (505 of 516 messages) of the time. The alarm algorithm is an improvement over current alarms found on most ventilators because its alarm messages specifically identify failures in the patient breathing circuit or ventilator. The system may improve patient care by helping critical care personnel respond more rapidly and correctly to critical events.

Algorithms↗
PubMed1988

Calcium channel antagonists. Part II: Use and comparative properties of the three prototypical calcium antagonists in ischemic heart disease, including recommendations based on an analysis of 41 trials.

An analysis of 41 trials of angina of all varieties confirms that calcium antagonists are an important advance and are now established therapy for these syndromes. In effort angina, verapamil in a dose of 360-480 mg daily is better than propranolol in standard doses. Although nifedipine is highly effective against vasospastic angina, its use in threatened myocardial infarction or severe unstable angina is not supported by recent studies, unless combined with a beta-blocker. Diltiazem has recently been tested with apparent benefit in non-Q-wave myocardial infarction. Otherwise, these calcium antagonist agents all seem to have approximate equipotency in clinical ischemic syndromes including effort and vasospastic angina. Subjective side effects seem most troublesome in the case of nifedipine. All three calcium antagonists, especially nifedipine, have been successfully combined with beta-blocker therapy, yet occasional additive negative inotropic or chronotropic or dromotropic interactions may occur when verapamil or diltiazem is added to beta-blockade, and occasionally the direct negative inotropic potential of nifedipine may become evident. The choice between the calcium antagonists is determined not only by the clinical picture but also by the anticipated side effects in a given patient and by the overall cardiovascular status. In patients with supraventricular tachycardias or sinus tachycardia, verapamil or diltiazem is preferred, whereas in patients with a resting bradycardia or borderline heart failure nifedipine is likely to be chosen.

Angina Pectoris↗
PubMed2000

Prototype algorithm for automated determination of gastric slow wave characteristics.

An algorithm for determining the frequency and propagation time of the gastric slow wave has been designed for integration into a demand gastric pacing system. The algorithm analyses the serosal activity in both the time and frequency domains, and the results are compared to produce a conclusion only when the values are within 5% of each other. Thus, the probability of inappropriate intervention is reduced, at the expense of unidentified segments. The system is verified by comparing the conclusions produced by the algorithm with conclusions from hand analysis of seven canine and one human serosal recordings. The algorithm correctly identifies the slow-wave frequency in the distal portion of the stomach for 90% of the segments, while producing no incorrect results. Slow-wave propagation times in the antrum are correctly identified for 84% of the segments, with no incorrect identifications.

Algorithms↗