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Biomedical subjects

M Smith

Publications and source records attributed to M Smith.

At least 1,225 records · Page 68Linked to original sources
PubMed1981

Cardiovascular effects of intravenous administration of tetracycline in cattle.

Tetracycline chloride dissolved in saline was injected intravenously to seven cows. Two doses of tetracycline were used: 5 and 10 mg/kg b.wt, and the injections were given over a period of either 10, 60 or 300 sec. A number of the cows collapsed shortly after the injection was completed, usually when the 10 mg dosage was given in 60 sec. When the same dose was given over a period of 5 min none of the cows collapsed. A more or less pronounced drop in blood pressure could be detected during or shortly after the injection; in those cows which collapsed the blood pressure fell almost to zero. The predominant change in pulse rate in connection with the tetracycline administration was a decrease which could be quite marked, pulse rates falling as low as 10-20 per min. Simultaneously with these changes in blood pressure and pulse rate severe abnormalities in ECG could be observed. Pre-treatment with a normal therapeutic dose of calcium borogluconate intravenously prevented collapse in the cows and diminished the drop in blood pressure associated with an ensuing tetracycline injection. It is concluded that intravenous injection of tetracycline is hazardous, but that collapse can be avoided by giving the injection very slowly over a period of no less than 5 min.

Animals↗
PubMed1981

Pulmonary injury and prostaglandin production during endotoxemia in conscious sheep.

Prostaglandins F2 alpha, E2, and I2 (as 6-keto-PGF1 alpha) and TxA2 (as TxB2) were measured by radioimmunoassay in plasma and lymph from 12 conscious sheep with chronic lung lymph fistulas given Escherichia coli endotoxin (2-10 micrograms/kg) and followed for 24 h. Endotoxin produced a two-phase pulmonary injury. Phase 1 was characterized by transient severe pulmonary hypertension and increased lymph flow rate (QL). Plasma and lymph PGF2 alpha concentrations increased from base-line values of 0.13 +/- 0.08 and 0.30 +/- 0.10 ng/ml to 0.96 +/- 0.37 and 2.8 +/- 0.80 ng/ml, respectively. Values for TxB2 increased from 0.7 +/- 0.1 to 5.5 +/- 1.1 ng/ml in lymph and to 3.2 +/- 0.6 in plasma. Plasma PGI2 increased from 0.48 +/- 0.29 to 4.97 +/- 1.21 ng/ml and lymph PGI2 from 1.80 +/- 0.73 to 14.19 +/- 2.79 ng/ml. Phase 2 was characterized by moderately elevated pulmonary vascular pressures and a maintained high flow rate of protein-rich lymph. Lung lymph and plasma PGF2 alpha concentrations returned to base line. Lymph PGI2 decreased significantly to 5.23 +/- 2.47 ng/ml, whereas plasma PGI2 decreased to 2.70 +/- 1.07 ng/ml. We conclude that prostaglandins, particularly PGF2 alpha and prostacyclin, are released from the lung after endotoxemia and appear in lung lymph as sensitive indicators of pulmonary microvascular injury. Prostanoid production appears to temporally correspond with changes in the pulmonary microcirculation.

Animals↗
PubMed1981

An evaluation of the first production model of the Rank Hilger Chemispek multichannel electrolyte analyser.

The first production model of the Rank Hilger Chemispek multichannel analyser was evaluated. It is a six-channel machine for the analysis of sodium, potassium, chloride, bicarbonate, urea, and creatinine. We chose to run it at 120 samples per hour. The machine was shown to be economical in the volumes of both samples (200 microliters) and regents, flexible, accurate, and precise. It performance was better than that of other machines with a similar capacity and it is considerably cheaper.

Autoanalysis↗
PubMed1981

A report of Uhl's disease in identical adult twins: evaluation of right ventricular dysfunction with echocardiography and nuclear angiography.

The first example of Uhl's disease affecting identical adult twins is reported, offering support for the contention that a congenital developmental defect or hereditable tendency is the responsible cause. In one case, echocardiography and nuclear angiography proved to be valuable in making the diagnosis. Uhl's disease in the adult should be suspected among cases of isolated right ventricular enlargement and failure complicated by ventricular dysrhythmias. The diagnosis may be made using a combination of noninvasive tests, obviating the need for cardiac catheterization.

Adipose Tissue↗
PubMed1981

Assignment of the gene for acid beta-glucosidase to human chromosome 1.

The structural gene for human acid beta-glucosidase (GBA) has been assigned to chromosome 1 using somatic cell hybridization techniques for gene mapping. The human enzyme was detected in mouse RAG cell-human fibroblast cell hybrids by a sensitive double antibody immunoprecipitation assay using a mouse antihuman GBA antibody. No cross-reactivity between mouse beta-glucosidase and human GBA or neutral beta-glucosidase (GBN) was observed. Fifty-two primary, secondary, and tertiary manmouse hybrid lines, derived from three separate fusion experiments, were analyzed for human GBA and enzyme markers for the human chromosomes. Without exception, the presence of human GBA in these hybrid clones was correlated with the presence of human chromosome 1 or its enzymatic markers, phosphoglucomutase 1 (PGM1), and fumarate hydratase (FH). All other human chromosomes were eliminated by the independent segregation of GBA and their respective enzyme markers and/or chromosomes. Using a RAG X human fibroblast line with a mouse-human rearrangement of human chromosome 1, the locus for GBA was limited to the region 1p11 to 1qter.

Animals↗
PubMed1981

Separation of molecular species of sphingomyelin and ceramide by argentation and reversed-phase HPLC.

A convenient method for the separation of molecular species of complex lipids such as sphingomyelin and ceramide by argentation high performance liquid chromatography (HPLC) is described for the first time. Molecular species separation of these complex lipids was achieved for quantitative analysis and preparative work by the combined use of argentation and reversed-phase HPLC.-Smith, M., P. Monchamp, and F. B. Jungalwala. Separation of molecular species of sphingomyelin and ceramide by argentation and reversed-phase HPLC.

Animals↗
PubMed1981

Pulmonary microvascular injury from lipoxygenase infusion: comparison with endotoxemia.

We compared the response of the pulmonary microcirculation to a 5-hr infusion of soybean lipoxygenase with that seen after endotoxin. We monitored microvascular integrity using lung lymph flow QL and lymph/plasma (L/P) protein ratio in unanesthetized sheep. We noted a twofold to threefold increase in QL and a slight decrease in L/P ratio beginning about 1 hr after onset of the lipoxygenase infusion. Leukocyte count decreased significantly and lymph lysosomal enzyme activity increased. Pulmonary artery pressure initially increased from 16 to 31 mm Hg, then decreased to 25 mm Hg during continued infusion. Platelet count remained constant. Parameters returned to baseline several hours after infusion. This pulmonary vascular pressure and lymph flow response was very similar to that seen in the increased permeability phase of endotoxin. A decrease on the L/P ratio and a constant rather than a decreased platelet count were findings different from those seen after endotoxin.

Animals↗
PubMed1981

The effect of prostacyclin infusion on endotoxin-induced lung injury.

Lung injury produced by endotoxin is characterized by both pulmonary hypertension and increased pulmonary vascular permeability. Prostacyclin (PGI2) has been found to be a vasodilator and a membrane stabilizer. The purpose of this study was to determine the effectiveness of PGI2 in preventing endotoxin injury. Eight sheep with chronic lung lymph fistula were given both Escherichia coli endotoxin (2 microgram/kg) alone and endotoxin plus an immediate infusion of PGI2 (0.1 to 0.2 microgram/kg/min) for a 5-hour period; the studies were performed 4 days apart. The endotoxin injury was characterized by early severe pulmonary hypertension, with pulmonary artery pressure increasing from 18 +/- 0.6 to 40 +/- 3.1 mm Hg and lung lymph flow (QL) increasing threefold. This was followed in about 3 hours by an increase in permeability characterized by an increasing lymph to plasma protein ratio (0.63 to 0.74) and a threefold increase in QL. In seven of eight animals infused with PGI2 the pulmonary hypertension and alteration in QL in the early and later phases were significantly decreased. In four paired studies, prostaglandins PGE, PGF2 alpha, and PGI2 as 6-keto PGF1 alpha were measured in lymph and plasma. PGF2 alpha and PGI2 were significantly increased in lung lymph during the early hypertensive phase immediately after endotoxin injection, but returned to baseline during the later phase. In the PGI2 infusion studies, PGF2 alpha showed the same pattern of response, but PGI2 was increased to much higher levels in lymph and plasma, as compared to values of endotoxin alone. The higher plasma values corresponded with less severe lung injury. The one animal not protected by PGI2 had the lowest plasma PGI2 level. We therefore found PGI2 to protect the lung against injury from endotoxin.

Animals↗
PubMed1981

Endotoxin-induced lung injury in unanesthetized sheep: effect of methylprednisolone.

Our purpose was to study the effect of methylprednisolone (MPS) on endotoxin-induced lung injury. We used lung lymph flow and lymph protein content at sensitive indicators of pulmonary microvascular integrity in unanesthetized sheep. Seven animals were given E coli endotoxin (2 micrograms/kg) alone and also endotoxin with MPS pretreatment (30 mg/kg) in paired separate studies. The endotoxin injury was divided into an early hypertensive phase (30-90 minutes) characterized by a significant increase in pulmonary artery pressure (Ppa) and lymph flow, QL. This was followed later (3-5 hours) by a significant increase in protein-rich QL with normal pressures. MPS pretreatment significantly increased both injury phases in all animals. White cell count decreased in both groups; however, lymph beta-glucuronidase increased only in the nontreated group. Platelet count decreased in the nontreated group. Seven animals were then compared using endotoxin alone or with MPS treatment one hour after endotoxin. Only four of seven animals had a decrease in the lung injury after MPS treatment. We conclude that methylprednisolone is very effective in preventing lung injury, but only minimally effective in reversing the injury from endotoxin.

Animals↗
PubMed1981

[Topographic radiologic anatomy of the right subcarinal and retrobronchial pulmonary recess (author's transl)].

Depending on the size of the subcarinal and retrobronchial recess the medial wall of the right and perhaps the left main bronchus can be recognized. The medial extension of the recess is very variable. On lateral films with slight anterior rotation of the right shoulder, the posterior wall of the right main bronchus can be shown in 97% of patients. Awareness of this recess and its boundaries is essential for diagnosis of subcarinal and tracheobronchial node enlargement. The following 4 signs will assist in diagnosis: 1. The dorsal margin of enlarged nodes may be recognized posterior and inferior to the carina. 2. The posterior wall of the right main bronchus can no longer be seen. 3. The medial wall of the right main bronchus can no longer be seen. 4. Clearer demonstration of the right main bronchus or bronchus intermedius occurs, due to an "air bronchogram" effect. Due to the application of these 4 signs, enlargements of the subcarinal or tracheobronchial nodes can be recognized, at a stage where the tracheal bifurcation is not yet splayed, and when the nodes have not yet caused bronchostenosis.

Bronchography↗
PubMed1981

Reversed-phase high performance liquid chromatography of phosphatidylcholine: a simple method for determining relative hydrophobic interaction of various molecular species.

A convenient method for the separation of molecular species of phosphatidylcholine (PC) by reversed-phase high performance liquid chromatography (HPLC) is described. PC species from egg, bovine brain, and porcine liver were resolved into 11-13 separate peaks on a Nucleosil-5-C18 reversed-phase column with methanol-1 mM potassium phosphate buffer, pH 7.4, 9.5:0.5 (v/v) as the solvent. Detection was at 205 nm. PC species were primarily resolved due to specific hydrophobic interaction of their fatty acid side chains with the alkyl ligand of the stationary phase. The retention time and therefore the hydrophobic interaction of acyl chains of PC species increased logarithmically as the total number of carbon atoms in the chains increased in the homologous series. The retention times decreased nonlinearly as the number of double bonds in the fatty chains increased. Introduction of the first double bond in the side chain reduced the retention time to the greatest extent. From the chromatography data the reduction in the retention time was calculated to be equivalent to 1.8 carbon atoms compared to the fully saturated PC. Further introduction of 2, 3, 4, 5, and 6 double bonds in the same side chain reduced the retention time additionally, equivalent to 1.4, 1.2, 1.0, 1.0, and 1.0 less carbon atoms. Each molecular species of PC was assigned a "Hydrophobic Carbon Number" (HCN) based upon the total number of carbon atoms ad double bonds in the side chain. PC molecules with the same HCN had the same retention time. The average HCN was calculated for various PC preparations and found to be remarkably the same for all the three different naturally occurring sources considering a wide variety of different fatty acid compositions of each type. HCN provides a simple measure of relative hydrophobicity of each PC molecule.

Animals↗
PubMed1981

Collagen-induced arthritis in the rat: modification of immune and arthritic responses by free collagen and immune anti-collagen antiserum.

Inbred Wistar strain rats developed a polyarthritic disease when injected intradermally with Freund's incomplete adjuvant (FIA) containing porcine or bovine type II collagen (CII). In contrast, neither allogeneic rat CII nor porcine proteoglycan monomer were arthritogenic, although both were, to some extent, immunogenic. Animals passively transfused with immune serum containing anti-CII antibodies did not develop arthritis and showed greatly reduced anti-CII humoral immune responses (measured by an enzyme-linked immunosorbent assay) when the serum was administered at the time of and subsequent to challenge with arthritogenic porcine CII. Similarly, the intravenous injection of animals sequentially with 100 microgram soluble CII and 1 ml immune anti-CII antiserum, 9 and 8 days respectively before challenge with arthritogenic CII, abrogated the arthritic response and depressed the humoral anti-porcine CII and anti-rat CII antibody titres more than tenfold. It is concluded that the immune status of the recipient rats with respect to CII is crucially important in determining the nature of the immune and arthritic response to CII appropriately administered in FIA.

Animals↗