Search PubMed⌕ Search

Biomedical subjects

M Smith

Publications and source records attributed to M Smith.

At least 1,117 records · Page 62Linked to original sources
PubMed1984

Continuous monitoring of critically ill patients with transcutaneous oxygen and carbon dioxide and conjunctival oxygen sensors.

Transcutaneous (PtcO2) and conjunctival (PcjO2) oxygen tensions and transcutaneous (PtcCO2) carbon dioxide tension were serially measured in 31 critically ill patients. Sixteen patients maintained a normal or greater blood pressure and 15 patients were severely hypotensive (MAP less than 60 mm Hg) or suffered cardiac arrest while in the emergency department. In hemodynamically stable patients, the correlations between PtcO2 and PaO2, PcjO2 and PaO2, and PtcCO2 and PaCO2 were significant, with correlation coefficients (r values) of 0.62, 0.48, and 0.73, respectively. In hemodynamically unstable patients, there was poor correlation between PtcO2, PcjO2, PtcCO2, and arterial blood gas values. In the severely hypotensive patients, however, PtcO2 and PcjO2 were sensitive real-time monitors of peripheral perfusion and tissue oxygen delivery. Increases in PcjO2 and PtcO2 occurred within three minutes in patients who regained a palpable blood pressure from a pulseless baseline. PtcO2 fell one to five minutes after the loss of blood pressure in patients whose clinical condition deteriorated in the emergency department. Decreases in PcjO2 from previously stable levels occurred over three to four minutes before loss of blood pressure. Transcutaneous and conjunctival sensors can be used as continuous monitors of respiratory status in hemodynamically stable patients. In severely hypotensive patients and during cardiopulmonary resuscitation, these sensors no longer accurately reflect arterial blood gases, but act as sensitive real-time monitors of cardiac function and peripheral perfusion. PcjO2 can detect deterioration of clinical state before alterations in blood pressure occur.

Adult↗
PubMed1984

In vivo correlation of thermodilution cardiac output and videodensitometric indicator-dilution curves obtained from contrast two-dimensional echocardiograms.

In previous studies, indicator-dilution curves obtained by videodensitometry of contrast two-dimensional echocardiograms have shown close correlation with measurements of blood flow in vitro. In this study the technique was extended and contrast indicator-dilution curves obtained in vivo were correlated with simultaneous cardiac output measurements determined by thermodilution in eight dogs. Two-dimensional echocardiograms of the left ventricle were performed with the transducer on the myocardium during left atrial-pulmonary vein injection of 10 cc of a 1 X 10(-4) concentration of 30 mu diameter microballoons. A total of 148 injections were performed at 37 levels of cardiac output (1.70 to 7.90 liters/min) induced by alterations of left ventricular preload, isoproterenol and propranolol. Indicator-dilution curves were obtained from recordings of the analog signal of a linear videodensitometer focused on the left ventricle. Linear regression analysis between total area of the indicator-dilution curves and cardiac output yielded correlation coefficients (r) of 0.77 to 0.96 (mean 0.90) for individual dogs, and 0.65 for all cardiac output determinations in all dogs. Analysis of indicator-dilution curve area by the forward triangle-exponential decay method yielded enhanced individual coefficients of 0.90 to 0.97 (mean 0.94) with cardiac output and 0.61 for the group of animals. It is concluded that echographic indicator-dilution curves obtained from uniform size microballoons and videodensitometry may be obtained in vivo and correlate with cardiac output measurements.

Animals↗
PubMed1984

Molecular cloning and characterization of a cDNA for the beta subunit of human alcohol dehydrogenase.

Human alcohol dehydrogenase (ADH) is encoded by at least five genes that fall into three classes. The class I ADH genes encode the three closely related alpha, beta, and gamma polypeptides. Molecular genetic analysis of class I ADH genes has been initiated by isolating a cDNA clone from a human adult liver cDNA library. A synthetic oligonucleotide mixture encoding a portion of the beta subunit of ADH was used as an in situ hybridization probe for the cDNA library. One positively hybridizing clone, pADH12, which contained an 1100-base-pair cDNA insert, was subjected to DNA sequence analysis. The sequence indicated that the cDNA encoded information for the carboxyl-terminal 91 amino acids of a class I ADH and a 3' untranslated region of 593 nucleotides. Comparisons with the carboxyl terminus of the human ADH beta subunit indicated that the cDNA encoded the beta polypeptide. This probe may facilitate genetic studies of various human alcohol-related syndromes, as well as enable basic molecular studies on human ADH gene expression.

Adult↗
PubMed1984

Biologically active synthetic fragments of epidermal growth factor: localization of a major receptor-binding region.

A primary receptor-binding region of mouse epidermal growth factor (EGF) was identified by comparing the relative affinities of selected synthetic fragments with overlapping sequences in the EGF receptor-binding assay, using human foreskin fibroblasts. Only synthetic peptides containing the amino acid residues 20-31 in the mouse EGF sequence showed the ability to compete with 125I-labeled EGF in binding to EGF receptors. The affinities of the cyclic EGF fragment [Ala20]EGF-(14-31) and the linear [(S-acetamidomethyl)-Cys20,31]-EGF-(20-31) were approximately 1/10(4) of the affinity of EGF. Despite their reduced receptor affinities, these two peptides exhibited the in vitro biological activities of native EGF, while fragments from other regions of the EGF molecule were devoid of these biological properties. The peptides induced DNA synthesis in human foreskin fibroblasts as measured by [3H]thymidine incorporation into DNA. They also induced EGF receptor clustering and activated the EGF-sensitive kinase, enhancing the autophosphorylation of EGF receptors in a dose-related manner. Moreover, a major antigenic determinant of EGF for rabbit anti-EGF antibodies was identified within this same localized region of the EGF molecule by competition experiments utilizing the synthetic EGF fragments. The predominant EGF antigenic determinant(s) was also found within the fragment [(S-acetamidomethyl)Cys20,31]-EGF-(20-31). The accessibility of the residues in positions 20-31 for antibody recognition is consistent with the conclusion that these residues constitute or contain a major receptor-binding region for EGF.

Binding, Competitive↗
PubMed1984

The yield and nutrient content of colostrum and milk of women from giving birth to 1 month post-partum.

The intake of mammary secretion from delivery to day 5 post-partum was determined by test-weighing nine infants using an integrating electronic balance. The mean yield of colostrum for the first 24 h after birth was 37.1 (range 7.0-122.5) g and was 408 (range 98.3-775) and 705.4 (range 452.5-876) g/24 h on days 3 and 5 post-partum respectively. The milk yield of mothers on either day 14 or 28 post-partum was determined by test-weighing the mother. The mean milk yield was 1.156 (SD 0.167) kg/24 h. A significant correlation (P less than 0.001; r 0.85, n 42) was found between milk yield measured by test-weighing the infant and milk yield measured by test-weighing the mother, confirming that it is possible to obtain a similar estimate of milk consumed using either of the two methods of test-weighing. There was a significant positive correlation (P less than 0.001) between lactose concentration and milk yield for the first 5 d post-partum (r 0.76, n 22); a significant correlation (P less than 0.001) between protein concentration and milk yield (r-0.74, n 22) and no significant correlation between fat concentration and milk yield for the period studied. The calculated energy intake of infants during the first 24 h after birth was only 0.12 (range 0.02-0.29) mJ. This increased to 1.44 (range 0.83-2.18) and 2.99 (range 2.49-4.06) mJ/24 h by days 3 and 14-28 post-partum respectively.

Body Weight↗
PubMed1984

Oligonucleotide-directed mutagenesis: a simple method using two oligonucleotide primers and a single-stranded DNA template.

This paper presents a simple and efficient method for oligonucleotide-directed mutagenesis using vectors derived from single-stranded phage. This modification of our previously published procedure (Zoller and Smith, 1982) features the use of two primers, one of which is a standard M13 sequencing primer and the other is the mutagenic oligonucleotide. Both primers are simultaneously annealed to single-stranded template DNA, extended by DNA polymerase I (large fragment), and ligated together to form a mutant wild-type gapped heteroduplex. Escherichia coli is transformed directly with this DNA; the isolation of covalently closed circular DNA as in our previous report is not necessary. Mutants are identified by plaque lift hybridization using the mutagenic oligonucleotide as a probe. As an example of the method, a heptadecanucleotide was used to create a T----G transversion in the MATa gene of Saccharomyces cerevisiae cloned into the vector M13mp5. The efficiency of mutagenesis was approximately 50%. Production of the desired mutation was verified by DNA sequencing. The same procedure has been used without modification to create insertions of restriction sites as well as specific deletions of 500 bases.

Coliphages↗
PubMed1984

Emergency medicine.

Explore the source record for details and available documents.

Clinical Clerkship↗
PubMed1984

Conjunctival and transcutaneous oxygen monitoring during cardiac arrest and cardiopulmonary resuscitation.

To define the utility of transcutaneous and conjunctival oxygen sensors in the emergency setting, we measured serial conjunctival (PcjO2) and transcutaneous (PtcO2) oxygen tensions during CPR in 11 patients. There was no significant correlation between PaO2 and PtcO2 or PcjO2. Improvement or deterioration in clinical condition as assessed by return or loss of palpable blood pressure was consistently and accurately reflected by PcjO2 and PtcO2. PcjO2 responded to changes in physiologic state more rapidly than did PtcO2, with a reaction time of approximately 60 sec. Conjunctival and transcutaneous oxygen sensors provided continuous information on the effectiveness of CPR in terms of peripheral perfusion and tissue oxygenation, and were a valuable adjunct in monitoring the clinical condition of these critically ill patients.

Conjunctiva↗
PubMed1984

Detection of blood volume deficits through conjunctival oxygen tension monitoring.

Because acute blood loss may produce abnormal tissue perfusion and oxygenation before affecting blood pressure, we measured conjunctival (PcjO2) and arterial (PaO2) oxygen tensions and blood volume in 16 normotensive emergency department patients whose histories were consistent with significant blood loss. All eight patients with measured blood volume less than 85% of normal, as well as two euvolemic patients, had a PcjO2/PaO2 value of 0.57 or less, yielding a sensitivity of 100%, specificity of 75%, and positive predictive value of 80%. Lowering the cutoff point to 0.50 increased specificity and positive predictive value to 100% while reducing sensitivity to 88%. These results demonstrate that the PcjO2/PaO2 ratio is an early, sensitive, and specific indicator of significant blood volume deficit.

Adolescent↗
PubMed1984

Articular chondrocalcinosis in a hospital population: an Australian experience.

A group of hospital patients aged 55 years or over (53 men, 74 women) were screened for articular chondrocalcinosis (ACC) with high-resolution radiographs of knees, wrists, hand and pelvis. Two men (4%) aged 79 and 86 years had ACC involving knees, wrists and symphysis pubis. Both had clinical joint disease and radiological osteoarthritis (OA). Eighteen women (24%) had ACC with sites affected including the knees (89%), wrists (39%) and symphysis pubis (44%). Metabolic screening did not reveal any predisposing factors in patients with ACC. Symptoms and signs of joint disease were not significantly more common in women with ACC compared to those without ACC, and 44% of those with knee calcification were clinically asymptomatic and had no evidence of OA radiologically. However, the presence of knee ACC significantly increased the risk for OA in the same knee by a factor of three-to-four while knee calcification was associated with the more severe grades of radiographic OA.

Aged↗
PubMed1984

Construction and properties of a ribosome-binding site mutation in gene E of phi X174 bacteriophage.

Oligodeoxyribonucleotide mutagenesis has been used to produce a G----A mutation at nucleotide 557 of the phi X174 genome. This changes the ribosome-binding sequence GAGG of gene E to GAAG without affecting the amino acid, glutamine, encoded by the overlapping gene D. The phi X174rb(E)557 mutant does not lyse infected Escherichia coli C and therefore results in the accumulation of a large number intracellular mature phage particles. Thus, the mutation inactivates production of the gene E lytic product, presumably by blocking translation of gene E, without affecting other phage functions.

Bacteriophage phi X 174↗
PubMed1984

Intrachromosomal movement of genetically marked Saccharomyces cerevisiae transposons by gene conversion.

In this paper, we describe the movement of a genetically marked Saccharomyces cerevisiae transposon. Ty912(URA3), to new sites in the S. cerevisiae genome. Ty912 is an element present at the HIS4 locus in the his4-912 mutant. To detect movement of Ty912, this element has been genetically marked with the S. cerevisiae URA3 gene. Movement of Ty912(URA3) occurs by recombination between the marked element and homologous Ty elements elsewhere in the S. cerevisiae genome. Ty912(URA3) recombines most often with elements near the HIS4 locus on chromosome III, less often with Ty elements elsewhere on chromosome III, and least often with Ty elements on other chromosomes. These recombination events result in changes in the number of Ty elements present in the cell and in duplications and deletions of unique sequence DNA.

DNA Transposable Elements↗
PubMed1984

Psychiatric assessment of children. II. Comparison with mothers.

An attempt is made to demonstrate the relevance of a diagnostic method described in a preceding paper by comparing observations in 95 children aged 7-8 with independent findings in their mothers. The mothers had been chosen at random and exhaustively studied by another team at the time of the pregnancies which resulted in the birth of the children of our study.

Attention Deficit Disorder with Hyperactivity↗
PubMed1984

Alcohol and aggression in men: a comparison of brewed and distilled beverages.

The effects of distilled and brewed alcoholic beverages on aggressive behavior were compared in a 2 x 2 factorial design with 16 subjects per cell (N = 64 men social drinkers). One-half of the sample population was told that they would be consuming an alcohol (distilled spirits) beverage and the other half that they would be consuming beer. Within each of these conditions, one-half of the subjects received the expected drug (alcohol) and one-half was given a corresponding placebo beverage. Aggression was measured using a modified version of the Buss aggression machine. Subjects who consumed beer or believed that they were consuming beer were significantly less aggressive than subjects who consumed distilled spirits or believed that they were consuming distilled spirits. Differences between subjects receiving the drug (alcohol) and the placebo were not significant.

Adolescent↗
PubMed1984

Health promotion for educators: impact on health behaviors, satisfaction, and general well-being.

A random sample of 117 teachers in three treatment schools and one control school participated in a health survey at the beginning and end of the spring semester. Teachers in the treatment schools participated in a 10-week health promotion program which emphasized exercise, stress management, and nutrition. Comparison of pre- and post-survey data indicated that teachers in the treatment schools increased their participation in vigorous exercise, improved their physical fitness, lost weight, lowered their blood pressure, reported a higher level of general well-being, and were better able to handle job stress.

Adult↗