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Biomedical subjects

D Lawson

Publications and source records attributed to D Lawson.

178 records · Page 10Linked to original sources
PubMed1966

Some observations on the penetration of antibiotics through mucus in vitro.

A study has been made on the penetration values in vitro of antibiotics through hog gastric mucin at pH 7.4. Determinations have also been done on the binding of antibiotics to mucus and human plasma. The mucolytic agent N-acetyl cysteine has been studied in regard to its effect on antibiotics penetrating mucus and for any possible inactivation of antibiotics.

Acetylcysteine↗
PubMedDate not supplied

The lack of correlation between experimental metastatic potential and platelet aggregating activity of B16 melanoma clones viewed in relation to tumor cell heterogeneity.

Two widely used B16 melanoma cell lines of low and high lung colonizing potential (B16-F1 and B16-F10) were compared in their ability to induce platelet aggregation. The results of these experiments showed a reproducible difference in platelet aggregating activity of these two cell lines which directly correlated with their lung colonizing potentials. However, when clones were derived from these heterogeneous cell lines and tested for experimental metastatic potential, platelet aggregating ability and Met-72 expression, no correlation could be attached to the platelet aggregating activity of the clones. Results of these experiments provide direct evidence that platelet aggregation is not an accurate index of experimental metastatic potential of tumor cell clones, nor is it an essential trait of all metastatic cells. The ability of tumor cells to induce platelet aggregation is examined and discussed in the context of cellular heterogeneity.

Animals↗
PubMedDate not supplied

Rupture of the peroneus longus tendon.

The authors report a case of fracture of the os peroneum with diastasis in a 34-year-old woman. This represents one of the few cases of this type of fracture to be reported in the literature. This injury must be included in the differential diagnosis of a sprained ankle, and only careful examination of serial roentgenograms can prevent an incorrect diagnosis.

Adult↗
PubMedDate not supplied

Current distribution under electrodes in relation to stimulation current and skin blood flow: are modern electrodes really providing the current distribution during stimulation we believe they are?

Carbonized rubber electrodes were tested extensively when they were first developed 30 years ago, but modern carbonized rubber electrodes have not received the type of scrutiny that the first electrodes received. Modern electrodes differ from the original electrodes in that they come with a self-adhesive electrode gel called hydrogel as part of their composition. The present study was undertaken to examine the current distribution and impedance characteristics of five brands of carbonized rubber electrodes and to examine the current distribution between electrodes during electrical stimulation in six subjects. Several different electrode sizes were tested between 3 and 10 cm. The current flow between the electrodes was determined by measuring the voltage across the skin on human subjects in 15 discrete locations between the electrodes. Blood flow was also measured between the electrodes with a laser Doppler flow meter to assess the physiological effect of current distribution on the skin at several skin temperatures. The results of these studies showed that at low currents, such as is used in TENS, very little current is actually applied through the skin due to the high impedance of the electrodes. At current levels normally used for electrical stimulation for functional movement, while current flow is better in most electrodes, it is very uneven, resulting in high current density in the centre of the electrodes and a fall off of at least 50% in current intensity at the edges of the electrode. There was very little difference in current density between small and large electrodes due to the high current density in the centre. Skin blood flow altered the movement of current between the electrodes and also may contribute to electrode performance. The implication of these studies is that electrode design needs to be altered for better current distribution, especially at low stimulation currents.

Adult↗
PubMedDate not supplied

Treatment of shivering after epidural lidocaine.

The effectiveness of intravenous meperidine and warm local anesthetic for prevention of postanesthetic shivering was evaluated in urology patients undergoing epidural blockade for extracorporeal shockwave lithotripsy. When administered before the blockade, meperidine, 12.5 mg or 25 mg, was not significantly better than saline placebo for preventing postepidural shivering. Changes in the concentrations of catecholamines or lidocaine did not result in differences between patients who shivered and those who did not shiver. In a second experiment, patients receiving body-temperature or room-temperature epidural lidocaine did not differ with respect to the incidence of postanesthetic shivering, onset of sensory blockade, or core temperature during a 30-minute observation period. The authors concluded that neither meperidine, in doses employed, nor body-temperature lidocaine prevents shivering after epidural blockade. This shivering appears to be different from that observed during emergence from general anesthesia.

Anesthesia, Epidural↗
PubMedDate not supplied

Display adaptor for the Vitatek #511 monitor and the Puritan-Bennett CO2 analyzer.

Many CO2 infrared analyzers require additional graphics devices for continuous CO2 waveform display. An adaptor was designed to integrate the output of a Puritan-Bennett infrared CO2 analyzer into the display of a Vitatek #511 patient monitor. The adaptor is made with inexpensive off-the-shelf components and proved successful during more than six months of use.

Anesthesiology↗