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Biomedical subjects

M M Smith

Publications and source records attributed to M M Smith.

At least 217 records · Page 12Linked to original sources
PubMed1980

Postoperative thoracotomy. Effect of transcutaneous electrical nerve stimulation on forced vital capacity.

The purpose of this study was to measure the effects of transcutaneous electrical nerve stimulation on patients who had undergone thoracotomies, using the objective physiological measurement of forced vital capacity. Twenty-one patients were randomly assigned to an experimental group (n = 11) or a control group (n = 10). Each group performed three trials of forced vital capacity testing over a 20-minute period. In addition, the experimental group was given a 10-minute treatment of transcutaneous electrical nerve stimulation at the sites of greatest pain. The data indicated a statistically significant increase in forced vital capacity during the stimulation (p less than .01), suggesting that transcutaneous electrical nerve stimulation during application improves chest expansion and mobility in patients who have had thoracotomies.

Adolescent↗
PubMed1980

Lung mechanics after cardiac valve replacement.

Fourteen patients undergoing single aortic or mitral valve replacement had measurements made of lung volumes, static pressure-volume (P-V) relationships, and conductance-pressure relationships during deflation before operation and again between one and two years later. At follow-up, total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), and static tidal compliance (slope of static P-V deflation line for one litre above FRC) had increased significantly, in association with a decrease in heart size. There was a change in the shape and position of some P-V curves both in the aortic and mitral patients. In the patients with aortic disease P-V deflation curves shifted to the left after operation. In the patients with mitral disease the P-V deflation curves before operation crossed those measured after operation, so that at high lung volumes recoil became less after operation, but at low lung volumes recoil increased. Conductance had increased at high lung volumes. The data suggest that in longstanding pulmonary congestion, airways are more rigid making them less distensible at high and less compressible at low transpulmonary pressures than after operation when congestion has been at least partly relieved.

Adult↗
PubMed1979

Structure and histogenesis of tooth plates in Sagenodus inaequalis Owen considered in relation to the phylogeny of post-Devonian dipnoans.

The histology of tooth plates of Sagenodus inaequalis has been investigated to obtain information on the histogenesis of the tissue. The histological mechanisms of growth and replacement of the tooth plate are described in terms of an increase in area of the tooth plate by addition of denticles to the lateral margins of the ridges, replacement of worn dentine at the tritoral surface by basal growth of dentine and invasive growth of dentine into the surrounding bone at the anterior and medial margins. The histogenesis of a specialized character for dipnoans is described, namely hypermineralized dentine, or petrodentine, within the tooth plates. This has placed an advanced character further back in the phylogenetic organization of dipnoans than was previously recognized. The implications of these observations are discussed in relation to proposed phylogenies and previous observations on tooth plates of other dipnoans. It is concluded that Sagenodus inaequalis shared a common ancestor with both the ceratondontids and the lepidosirenids. A sequence is proposed for the phyletic relationship of tooth plate-bearing dipnoans. From a consideration of the features of histogenesis of this specialized dentine, the alternative terminologies are reviewed and petrodentine (Lison 1941) chosen for the hypermineralized dentine and syndentine (Thomasset 1928) as the collective term for the entire mass of dentine in the tooth plate.

Animals↗
PubMed1979

Identification tests for propantheline bromide.

A method is described for the isolation and identification of propantheline bromide from bulk drug substances and dosage forms, both alone and in combination with other drug substances. The method permits the specific identification of the intact drug substance, using both infrared spectroscopy and thin layer chromatography.

Chromatography, Thin Layer↗
PubMed1978

Analysis of RNA initiated in isolated mouse myeloma nuclei using purine nucleoside 5'[gamma-S]triphosphates as affinity probes.

The purine ribonucleoside triphosphate analogues adenosine 5'[gamma-S]triphosphate and guanosine 5'[gamma-T]triphosphate were used as affinity probes for studying RNA chain initiation in isolated nuclei from the mouse myeloma 66.2 cell line. Transcripts initiated with either nucleotide analogue were isolated by affinity chromatography on a mercury-agarose affinity column. The binding was specific and dependent upon the inclusion of the sulfur nucleotide analogues in the in vitro synthetic reaction. Several lines of evidence indicate that the affinity-labeled RNA is initiated in vitro. First, the sulfur nucleotide is recovered in high yield as a single nucleoside 5'[gamma-S]triphosphate 2',3'-monophosphate product following alkaline hydrolysis of RNA bound to the affinity column. Second, authentic ribosomal 5S RNA is known to initiate with GTP; in vitro 5S RNA is bound to mercury-agarose only if [gamma-S]GTP is used as the affinity label in the synthesis, and not if [gamma-S]ATP is used. Under the conditions studied, nuclei incorporated 1.2--2.4 pmole of UMP per 10(6) nuclei per min, and the rate of synthesis was unaffected by substitution of the nucleotide analogues for the normal nucleotides. The percentage of the total RNA synthesized that was incorporated into sequences initiated in vitro was 7.8 +/- 1.5% with [gamma-S]ATP and 9.6 +/- 6.4% with [gamma-S]GTP. The size of the total RNA synthesized, determined by sedimentation on sucrose density gradients containing dimethylsulfoxide, ranged from less than 5S to 45S, and the size of the affinity-labeled sequences ranged from less than 5S to 28S. Approximately half of the incorporation into RNA initiated in vitro was sensitive to a concentration of alpha-amanitin which selectively inhibits polymerase II activity. Most of the remaining incorporation into initiated sequences can be abolished by concentrations of alpha-amanitin that are inhibitory for polymerase III activity. Over 70% of the total incorporation into ribosomal 5S RNA transcripts was into sequences initiated in vitro. This initiation was catalyzed by polymerase III and was specific for GTP as the initiating nucleotide. The RNAase T1 fingerprint of the newly initiated 5S RNA indicates that this gene is accurately initiated and faithfully elongated in vitro. The use of these affinity label probes provides much greater sensitivity for studying the initiation of RNA in vitro.

Amanitins↗
PubMed1978

Enhancing aniline blue fluorescent staining of cell wall structures.

Prior staining with the periodic acid-Schiff reaction, toluidine blue O, Congo red, or Calcofluor White M2R New, or reduction by NaBH4 do not interfere with aniline blue-induced fluorescence of sieve plates, new cell walls, pit fields or tracheids in compression wood of conifers. Detail of such fluorescent structures is improved by these treatments because of increased contrast, reduced flare, and a quenching of autofluorescence.

Cell Wall↗
PubMed1977

Incorporation of purine nucleoside 5'-[gamma-S]triphosphates as affinity probes for initiation of RNA synthesis in vitro.

Synthetic DNA templates were transcribed by Escherichia coli RNA polymerase using nucleoside 5'-[gamma-S]triphosphates as one of the nucleotide substrates. Substitution of the thiol analogues for the normal nucleotides had no effect on the rate of RNA synthesis. RNA synthesized with either adenosine 5'-[gamma-S]triphosphate or guanosine 5'-[gamma-S]triphosphate was isolated with high efficiency on mercury-agarose columns prepared by activation with low concentrations of cyanogen bromide. Sulfur was shown to be incorporated at the 5' end of RNA by identification of the tetraphosphate HSpppA32p liberated after alkaline hydrolysis of HS(A-32pU)n (alternating copolymer synthesized by the action of E. coli RNA polymerase on d(A-T)n-d(A-T)n with adenosine 5'-[gamma-S]triphosphate and uridine 5'-[alpha-32P]triphosphate as substrates). Transcripts elongated but not initiated with these thiol analogues did not bind to the affinity column. This technique provides an extremely sensitive assay for RNA synthesis initiation in vitro, since initiated transcripts containing radiolabel throught the entire transcript can be isolated.

Chromatography, Affinity↗
PubMed1976

Increased elastic recoil as a determinant of pulmonary barotrauma in divers.

The elastic and conductive behaviour of the lungs were studied in sixteen divers during an interrupted deflation from total lung capacity (TLC.) The results in six divers, who had suffered pulmonary barotrauma (PBT) during shallow water diving, were compared with the findings in a control group of divers. Conductive behaviour and mean lung volumes were similar in the two groups. Compared with the control group, the PBT group had higher maximum transpulmonary pressures and a lower static pulmonary compliance, and deflated their lungs earlier. In relatively stiff lungs, an even distribution of elastance may increase susceptibility to barotrauma, because the more compliant zones are subjected to a greater strain. Pulmonary barotrauma appears to select from the total population of healthy divers those with lungs of decreased distensibility.

Diving↗
PubMed1976

Biosynthesis of mannan and mannolipids from GDP-Man by membrane fractions of sycamore cell cultures.

Membrane fractions have been prepared from sycamore (Acer pseudoplatanus) cell suspensions grown in liquid medium. These fractions catalyzed the transfer of mannoxyl-units from GDP-(14C) Man into a polymannoside, a mannolipid and oligosaccharide-lipids. The polymannoside was partially solubilized by proteolytic digestion or maceration in sodium dodecyl sulfate-urea mixtures. However no evidence is available of a covalent linkage between the biosynthesized glycan and peptides. The structural analysis of the (14C)mannan showed that the polysaccharide was a homopolymer of beta-(1 leads to 4) linked mannose with a few branches. During the incubation of the membranes with the substrate, the polymer chains elongated with a large number of sugar units and contained 25 to 40 hexose residues per non-reducing end monomer. GDP-Glc was a competitive inhibitor of the GDP-Man: beta-mannan mannosyl-transferase, whereas GDP-Man activated a GDP-Gle: beta-glucan glucosyl-transferase present in the same membrane preparation. Two kinds of glycolipids were synthesized in the presence of GDP-(14C)Man. The first (I) contained a polar moiety characterized as a mannose-phosphate and was very similar to polyprenyl-phosphate-mannose identified in plants by Alam and Hemming. The other mannolipid (II) was hydrolyzed by mild acid into labeled oligosaccharides of high molecular weight. This material was separated into two oligosaccharide fractions, the first (II A) of MW over 5000, the second (II B) of MW around 1700. II B contained at most two labeled mannose residues per chain, linked to the non-reducing end of unlabeled units which probably contained neutral sugars and N-acetyl-osamine(s) near the reducing end. Oligosaccharide II A seemed to contain one or several II B chains.

Cell Membrane↗
PubMed1976

Transcription in vitro of immunoglobulin kappa light chain genes in isolated mouse myeloma nuclei and chromatin.

Messenger RNA sequences for immunoglobulin kappa light chain were synthesized in vitro in isolated mouse myeloma nuclei using bound endogenous RNA polymerase (RNA nucleotidyltransferase; nucleoside triphosphate:RNA nucleotidyltransferase; EC 2.7.7.6) and from isolated myeloma chromatin using exogenous Escherichia coli RNA polymerase. The in vitro RNA was transcribed using 5-mercuriuridine triphosphate and separated from in vivo RNA by chromatography on an agarose sulfhydryl affinity column. Template restriction is retained in vitro since synthesis of kappa chain messenger RNA, As determined by hybridization with complementary DNA, was much more efficient in nuclei and chromatin isolated from myeloma 66.2 tissue culture cells, a kappa-chain-producing cell line, than from MOPC 315 tissue culture cells, a lambda-chain-producing cell line. Transcription of kappa chain messenger RNA was 25 times more efficient in myeloma 66.2 nuclei than in myeloma 66.2 chromatin.

Cell Nucleus↗
PubMed1975

Sea-blue histiocytes in mycosis fungoides.

A patient with tumor-stage mycosis fungoides and lymph node involvement had sea-blue (ceroid-containing) histiocytes in her bone marrow. Leukopenia, eosinophilia, and a mild type II beta-hyperlipoproteinemia were also features. Sea-blue histiocytes were demonstrated in the skin after the mycosis fungoides infiltrate had cleared with treatment. There is a possible interrelationship between the sea-blue histiocytes, the abnormal mycosis cells in the skin, and lipid metabolism.

Adult↗