Mammographic depiction of Poland's syndrome.
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Adult↗
Biomedical subjects
M S Johnson
Publications and source records attributed to M S Johnson.
An assessment of COMPOSER: a rule-based approach to modelling protein structure.
We describe COMPOSER, a computer program for modelling proteins which uses three-dimensional structures defined by X-ray analysis together with rules defined by their analysis and comparison. We discuss the modelling of phospholipases and serine proteinases of known structure to assess the errors associated with such models.
Amino Acid Sequence↗
Perspectives in medicine. Generalizability of homogenous samples in clinical trials.
Clinicians face a tremendous challenge in staying abreast of the medical literature. They must be particularly cautious to assess the safety and efficacy of new tests and treatments. Advances in research methodology have led to increasing use of homogenous or restricted samples. While this may improve the quality of the research design and reduce costs, there is a loss of generalizability. Often journal reports do not provide sufficient information so the clinician can decide whether the data and results reported are applicable to a patient population. This is particularly important to clinicians whose patients come predominantly from "special populations." Investigators, journal editors and clinicians need to increase their efforts to maximize considerations of generalizability in clinical trials.
Clinical Trials as Topic↗
Cost and acceptability of three syringe-pump infusion systems.
The fiscal impact and acceptability of implementing a syringe-pump infusion system at a 900-bed university teaching hospital where the minibag system has been in use is reported. Researchers selected three models of syringe pumps for evaluation: the Bard Harvard Mini-Infuser 150XL, the Becton Dickinson 360 Infuser, and the Strato Stratofuse System. Each pump was evaluated for three weeks on a medical-surgical unit and a hematology-oncology unit. Drugs to be infused were chosen after a literature review to determine which drugs had been successfully infused via syringe pump; 22 formulary medications were selected. Syringes were prepared as singly packaged doses or as doses prepared in bulk and packaged frozen. Control of the syringe pumps and microbore tubing was assigned to the inpatient pharmacy staff. Nurses and pharmacy personnel were apprised of the study and taught how to use the syringe pumps. Time-and-motion studies were performed in the sterile products preparation area, and a cost analysis was done. Nurses preferred syringe pumps over the minibag system because the pumps reduced the nursing time needed to infuse a drug, administered less fluid, provided consistent infusion rates, had alarms, and were relatively easy to use. The time required to prepare syringes did not differ substantially among syringe-pump models. It was estimated that using any of the evaluated pumps in place of the minibag system would save $126,500 during the three-year period 1988-91, primarily because of differences in the cost of disposable items. The syringe-pump infusion system is an acceptable and cost-effective alternative to the minibag system.
Costs and Cost Analysis↗
An analysis of the periodicity of conserved residues in sequence alignments of G-protein coupled receptors. Implications for the three-dimensional structure.
Twenty-three sequences from the family of G-protein coupled receptors have been aligned according to the 'historical alignment' procedure of Feng and Doolittle. Fourier transform analysis of this reveals that parts of five of the seven putative membrane-spanning regions exhibit a periodicity of conserved/nonconserved residues which is compatible with the periodicity of the alpha-helix. This would place the conserved residues on one side of the helix, which may face the inside of the proposed seven membered helical bundle.
Amino Acid Sequence↗
Studies on adenosine triphosphate transphosphorylases. XVIII. Synthesis and preparation of peptides and peptide fragments of rabbit muscle ATP-AMP transphosphorylase (adenylate kinase) and their nucleotide-binding properties.
Two peptide fragments, derived from the head and tail of rabbit muscle myokinase, were found to possess remarkable and specific ligand-binding properties (Hamada et al., 1979). By initiating systematic syntheses and measurements of equilibrium substrate-binding properties of these two sets of peptides, or portions thereof, which encompass the binding sites for (a) the magnesium complexes of the nucleotide substrates (MgATP2- and MgADP-) and (b) the uncomplexed nucleotide substrates (ADP3- and AMP2-) of rabbit muscle myokinase, some of the requirements for binding of the substrates to ATP-AMP transphosphorylase are being deduced and chemically outlined. One requirement for tight nucleotide binding appears to be a minimum peptide length of 15-25 residues. In addition, Lys-172 and/or Lys-194 may be involved in the binding of epsilon AMP. The syntheses are described as a set of peptides corresponding to residues 31-45, 20-45, 5-45, and 1-45, and a set of peptides corresponding to residues 178-192, 178-194, and 172-194 of rabbit muscle adenylate kinase. The ligand-binding properties of the first set of synthetic peptides to the fluorescent ligands: epsilon MgATP/epsilon ATP and epsilon MgADP/epsilon ADP are quantitatively presented in terms of their intrinsic dissociation constants (K'd) and values of N (maximal number of moles bound per mole of peptide); and compared with the peptide fragment MT-I (1-44) obtained from rabbit muscle myokinase (Kuby et al., 1984) and with the native enzyme (Hamada et al., 1979). In addition, the values of N and K'd are given for the second set of synthetic peptides to the fluorescent ligands epsilon AMP and epsilon ADP as well as for the peptide fragments MT-XII(172-194) and CB-VI(126-194) (Kuby et al., 1984) and, in turn, compared with the native enzyme. A few miscellaneous dissociation constants which had been derived kinetically are also given for comparison (e.g., the Ki for epsilon AMP and the value of KMg epsilon ATP obtained for the native enzyme) (Hamada and Kuby, 1978), and the K'd measured for Cr3+ ATP [corrected] and the synthetic peptide I1-45 (Fry et al., 1985b).
Adenosine Diphosphate↗
Distribution of trace element pollutants in a contaminated ecosystem established on metalliferous fluorspar tailings. 3: fluoride.
High total soil fluoride (10 000 microg g(-1)) in the metalliferous fluorspar tailings was reflected by elevated concentrations in standing live vegetation (300-1000 microg g(-1)); plant roots (c. 6000 microg g(-1)); plant litter (c. 4000 microg g(-1)); total body concentrations of invertebrates (400-4000 microg g(-1)) and the small mammals Microtus agrestis (120-360 microg g(-1)) and Sorex araneus (140-250 microg g(-1)). Seasonal changes in the standing live vegetation and the availability of soil fluoride to plants are discussed. Seasonal changes in total body concentrations of the small mammals were related to the age structure of the populations as well as dietary levels. In the small mammals, the concentration ratios were < 0.5 at the tailings dam and > 1.1 at the control site, indicating that both species were able to regulate fluoride accumulation at the higher levels of intake. Soft tissue concentrations were, as expected, very low compared to the hard tissues but, still, were generally significantly higher at the tailings dam compared to the control site. Evidence of dental fluorosis was found in Microtus agrestis, but not Sorex araneus.
Journal Article↗
Distribution of trace element pollutants in a contaminated grassland ecosystem established on metalliferous fluorspar tailings. 2: Zinc.
Concentrations of zinc in vegetation, invertebrates and small mammals in a grassland ecosystem derived from a mine waste vegetation scheme indicated the high concentration of zinc in the original tailings. However, the considerable differences in soil and vegetation zinc concentrations between the tailings and an uncontaminated site were not reflected in the invertebrate and small mammal communities. Invertebrate zinc levels and total body concentrations in Microtus agrestis L. (field vole) and Sorex araneus L. (common shrew) suggested a notable buffering of zinc absorption and tissue accumulation in the presence of substantially elevated dietary zinc. In the small mammals the skeleton appeared to function as the major storage site for zinc, possibly contributing to homeostasis in the soft tissues.
Journal Article↗
Distribution of trace element pollutants in a contaminated grassland ecosystem established on metalliferous fluorspar tailings. 1: lead.
Concentrations of lead in vegetation, invertebrates and small mammals in a grassland ecosystem evolved from a mine waste revegetation scheme indicated the high concentration of lead in the original tailings. Lead levels in invertebrates reflected dietary concentrations and feeding strategy, a pattern also true of the indigenous small mammals. Total body and tissue concentrations of lead in the herbivorous Microtus agrestis L. (field vole) and insectivorous Sorex araneus L. (common shrew) were significantly higher in the contaminated grassland than in an uncontaminated area, but concentration ratios (body:diet) were less than unity and there was no evidence of age-dependent accumulation of lead.
Journal Article↗
Origins and evolutionary relationships of retroviruses.
As is the case for some other RNA viruses, the amino acid sequences of retroviral proteins change at an astonishing rate. For example, the proteases of the human immunodeficiency virus (HIV) and the visna lentivirus with which it is often compared are as different as the proteases of fungi and mammals, and those of the human type I leukemia virus are as different from HIV or visna as are the proteins of humans and bacteria. That the sequences of retrovirus proteins can be recognized as sharing common ancestry with non-retroviral proteins implies that the vastly accelerated change has begun only recently or occurs very sporadically. Only a scheme whereby exogenous retroviruses exist as short-lived bursts upon a backdrop of germline-encoded endogenous viruses is consistent with the sequence data. Retroviruses are related to many other reverse transcriptase-bearing entities present in the genomes of eukaryotes. They also have proteins that are homologous with those of some plant and animal DNA viruses, and their reverse transcriptase is recognizably similar to sequences found in the introns of some fungal mitochondria. Computer alignment of all these sequences allows an overall phylogeny to be constructed that chronicles the history of events leading to infectious retroviruses.
Animals↗
Is EMS communicating with the FCC?
Radio communication problems in EMS run the spectrum from annoying to deadly. Dedicated radio frequencies for EMS, much like those exclusive to police and fire departments, are long overdue.
Emergency Medical Service Communication Systems↗
Glycyl-tRNA synthetase of Escherichia coli: immunological homology with phenylalanyl-tRNA synthetase.
Antibodies to Escherichia coli glycyl-tRNA synthetase (GlyRS) cross-react extensively with E. coli phenylalanyl-tRNA synthetase (PheRS). These data indicate that structural homology exists between these two enzymes, the only two aminoacyl-tRNA synthetases in E. coli having an alpha 2 beta 2 subunit structure. Although only limited similarities are found in the protein sequences deduced from their known gene sequences, the presence of common epitopes in GlyRS and PheRS adds to a rather long list of physical and chemical similarities between those proteins. In addition, antibodies directed at the alpha- and beta-subunits of GlyRS inhibit both GlyRS and PheRS in the same relative manner, indicating that the function as well as the structure of subunits is similar in each enzyme. In contrast, GlyRS antibodies did not cross-react with a number of other aminoacyl-tRNA synthetase activities from E. coli, yeast, or Bacillus.
Amino Acyl-tRNA Synthetases↗
Sequence comparisons of retroviral proteins: relative rates of change and general phylogeny.
The inferred amino acid sequences of 10 specific gene products from nine retroviruses were aligned by computer, all evolutionary distances between them calculated, and evolutionary trees constructed. Not unexpectedly, the various gene products are changing at different rates, the reverse transcriptase being the least and the envelope proteins the most different from one retrovirus to another. For the most part, trees based on the retroviral enzyme sequences are congruent, indicating that extensive genetic recombination has not been a major factor in the evolution of the central part of the genome. In the case of envelope protein sequences, however, the sequences clearly exhibit evidence of multiple cross-over events between quite distantly related retroviruses. A composite phylogenetic tree was constructed from the four retroviral enzyme sequences, and a number of important historical happenings were interpreted in the light of the time scale it affords.
Amino Acid Sequence↗
Prostaglandin production by corpora lutea of rhesus monkeys: characterization of incubation conditions and examination of putative regulators.
Prostaglandins (PGs) are produced by the corpus luteum (CL) of many domestic and laboratory species and may play a role in CL regulation. The production of PGs by luteal tissue of the rhesus monkey has yet to be clearly elucidated. The production of PGE2, PGF2 alpha, and 6-keto-PGF1 alpha by CL from rhesus monkeys and the incubation conditions (time and cell number) that permit assessment of their synthesis were examined. CL (n = 3 per characterization) were surgically removed from nonpregnant monkeys during the mid-luteal phase of the menstrual cycle (approximately 8-10 days after ovulation). Luteal tissue was dissociated and the cells were incubated at varying concentrations for increasing periods of time at 37 degrees C. Subsequent to defining incubation conditions, various exogenous factors were examined for their potential to modify PG production. Indomethacin, calcium ionophore, human chorionic gonadotropin (hCG), estradiol-17 beta (E2), progesterone (P), testosterone (T), dihydrotestosterone (DHT), and 1-4-6 androstatriene-3, 17-dione (ATD) were incubated with luteal cells in increasing doses. PG and P concentrations in the medium were determined by radioimmunoassay. PGs in the medium after 6 h incubation were detectable at all cell concentrations tested (50,000, 100,000, 200,000 cells/tube). Concentrations of PGs and P increased with cell number (p less than 0.05). Luteal cells (50,000 cells/tube) were incubated for times of 0-24 h. Concentrations of P, PGE2, and PGF2 alpha in the medium were relatively low prior to incubation (0 h), increased (p less than 0.05) linearly within the first 6-12 h, and plateaued through the remaining 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)
6-Ketoprostaglandin F1 alpha↗
The role of protein kinase C in LHRH-induced LH and FSH release and LHRH self-priming in rat anterior pituitary glands in vitro.
We have investigated the role of protein kinase C (PKC) in LHRH-induced LH and FSH secretion and LHRH priming. Hemipituitary glands from prooestrous rats were incubated with agents known to affect PKC and with or without LHRH, during which time the secretion of gonadotrophins was measured. Phorbol esters and phospholipase C, activators of PKC, released LH and FSH in a concentration-dependent manner and potentiated the LHRH-induced secretion of gonadotrophins in parallel with their ability to release these hormones alone. Inhibitors of PKC had either no effect on LH release (1-(5-isoquinolinesulphonyl)-2-methylpiperazine hydrochloride) or they augmented LHRH-induced gonadotrophin release (polymyxin B and 8-(N,N-diethylamino) octyl-3,4,5-trimethoxybenzoate). Neither the activators nor the inhibitors of PKC, when present with LHRH, caused any change in LHRH priming, even though the activators alone produced a release of gonadotrophins that showed a temporal pattern similar to that produced by LHRH priming. The profiles of effects on LH and FSH secretion were always qualitatively similar. These results show that PKC may be involved in general regulation of gonadotrophin release but that it is not important in acute responses to LHRH nor in LHRH self-priming.
Animals↗
Response of ventricular arrhythmias to propranolol in mitral valve prolapse.
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Adult↗
Emergency Medical Services communications planning in Alaska.
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Alaska↗
Accuracy of chart diagnoses of alcoholism in patients with a history of psychosis.
At two psychiatric clinics, 76 patients with a history of psychosis were interviewed by a researcher blind to the presence or absence of a chart diagnosis of alcoholism. Another person blind to research diagnosis ascertained the chart diagnosis of alcoholism. The lifetime prevalence of alcoholism, according to a structured research interview, was 45% at a mental health center, and 29% at a teaching hospital clinic. When compared to the lifetime prevalence of alcoholism, as determined by the research interview, chart diagnoses had sensitivities of 21% and 20%, respectively; specificity was 100% at both sites. Psychiatric chart diagnoses are not sensitive indicators of psychiatric patients' alcoholism.
Alcoholism↗