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Biomedical subjects

R W Smith

Publications and source records attributed to R W Smith.

At least 109 records · Page 6Linked to original sources
PubMed1988

Analysis of glutathione conjugates and related compounds by thermospray mass spectrometry.

A series of 17 cysteine, N-acetyl cysteine, glutathione, and N-trifluoroacetyl glutathione conjugates have been prepared, and their thermospray (TSP) spectra have been recorded in the positive and negative ion modes. The compounds undergo extensive fragmentation, which primarily occurs at the carbon-sulfur bonds. For most of the compounds, positive ion TSP is more sensitive than negative ion thermospray. Probably due to the thermal lability of these adducts, the quality of the spectra obtained are dependent on source conditions, requiring fine control of the vaporization/desolvation process.

Chemical Phenomena↗
PubMed1988

Percutaneous drainage of pancreatic and peripancreatic fluid collections.

Radiographically guided therapeutic percutaneous catheter drainage was used to manage 25 patients with 27 pancreatic and peripancreatic fluid collections. Nine of 11 (82%) noninfected and 11 of 16 (69%) infected collections were successfully managed with percutaneous drainage. Overall, eight complications and four deaths occurred in this group of patients. The morbidity and mortality in this series is somewhat higher than that previously reported in the radiologic literature. A discussion of the guidelines for percutaneous drainage is presented.

Abscess↗
PubMed1988

Breast reconstruction by the free lower transverse rectus abdominis musculocutaneous flap.

Free TRAM flap transfer for breast reconstruction following mastectomy overcomes the shortcomings of the pedicled TRAM flap. It ensures the perfusion of the entire flap via its dominant vascular pedicle and allows for flexibility in the design of the ensuing breast mound. The authors' experience with ten free lower TRAM flap transfers is reviewed. The present surgical technique is described and three cases are presented to illustrate its application. The advantages and limitations of the method are compared particularly with its pedicled version.

Abdominal Muscles↗
PubMed1988

The influence of dorsiflexion in the treatment of severe ankle sprains: an anatomical study.

Cadaver studies were performed to examine the applicability of ankle position to the treatment of ruptured fibulocollateral ligaments. Nonembalmed cadaver specimens were studied with anterior drawer and talar tilt stresses before and after division of the ligaments to simulate the sprained ankle. Dorsiflexion completely reduced the anteriorly subluxed talus and apposed the ends of the anterior talofibular ligament in specimens with divided lateral collateral ligaments. The dorsiflexion angle required to reduce the unstable ankle varied from 5 degrees to 15 degrees. These studies suggest that positioning the ankle in dorsiflexion instead of neutral or plantar flexion may have advantages in promoting a stable ankle if immobilization is chosen for treating a grade III sprain.

Ankle Injuries↗
PubMed1988

The functional recovery of revascularised colon and jejunum replacing the cervical oesophagus.

An experimental animal model was set up to study the comparative behaviour of revascularised transplants of colon and jejunum used to reconstruct the cervical oesophagus. Age, sex and size matched greyhound dogs were used in the study. An investigation of the physiological behaviour of the graft mucosa was carried out at 8 weeks using the mucosal specific activity of the enzyme Na+K+ATPase. The findings demonstrate a clear depression in the functional behaviour of the jejunal graft mucosa, while the colonic graft mucosa remained biochemically unchanged. The significance of these findings is discussed, and the conclusion drawn that they support the hypothesis that colon makes a more stable and functionally superior free graft than jejunum when replacement of the cervical oesophagus is required.

Animals↗
PubMed1988

Effects of pregnancy and lactation on the metabolism of bovine adipose tissue.

The incorporation of [2-14C] acetate into the triglycerides of adipocytes from bovine omental adipose tissue was at a minimum during peak lactation but increased again in late lactation. Similar but somewhat greater changes were observed for adipocytes from subcutaneous adipose tissue. In both tissues the activities of four enzymes concerned with fatty acid synthesis were lowest during peak lactation. In omental tissue lipoprotein lipase activity was lowest during peak lactation but there was a marked increase in its activity in the udder during lactation. In both omental and subcutaneous adipocytes the rate of glycerol release at peak lactation was higher than at all other stages of pregnancy and lactation. At peak lactation plasma insulin levels were low but growth hormone levels were higher than at all other stages of pregnancy and lactation. These results suggest that lipogenic precursors were diverted away from adipose tissue in early lactation and stored triglycerides were made available for use elsewhere in the body.

Acetates↗
PubMed1988

Metatarsophalangeal joint synovitis in athletes.

Metatarsophalangeal joint synovitis is a clinical entity of the forefoot with distinct findings. From a survey of 46 patients, characteristics and clinical findings are presented. Differential diagnosis and methods of treatment are discussed.

Adolescent↗
PubMed1987

Experimental assessment of free jejunal and colonic grafts of the esophagus.

The reconstruction of the cervical esophagus and the hypopharynx by revascularized bowel grafts has become a well-recognized treatment option and often is the method of first choice. Problems described by several protagonists of the standard revascularized jejunal graft have caused us to hypothesize that the colon provides both a suitable alternative and a solution to these problems. Experimental work in dogs demonstrates clear functional differences between colon and jejunum as free esophageal grafts. Video-fluoroscopic and manometric assessment of the two types of graft show that structurally and functionally the colon integrates into the new position in the esophagus better than does the jejunum.

Animals↗
PubMed1987

Determination of serum cortisol by thermospray liquid chromatography/mass spectrometry: comparison with gas chromatography/mass spectrometry.

The determination of serum cortisol by thermospray liquid chromatography/mass spectrometry (LC/MS) has been assessed. The method incorporates stable isotope dilution and immunoadsorption extraction. [M + H]+ ions are monitored during LC/MS. The within-assay reproducibility is satisfactory (coefficient of variation 7% at a concentration of 190 ng ml-1), though inferior to that achieved with the (more lengthy) procedure of gas chromatography/mass spectrometry (GC/MS). Satisfactory agreement between LC/MS (y) and GC/MS (x) data was observed (y = 0.934x + 12.4 ng ml-1; r = 0.968; n = 14). It is concluded that the generation of precise reference data for the assessment of routine cortisol assays is at present better achieved by GC/MS. LC/MS, however, provides satisfactory quantitative data via a more simple and rapid method.

Chromatography, Liquid↗
PubMed1987

Jejunum versus colon for free oesophageal reconstruction: an experimental radiological assessment.

The reconstruction of the cervical oesophagus and the hypopharynx by revascularised bowel grafts has become a frequently described treatment option. Problems with the standard jejunal grafts have led us to suggest that the colon provides a suitable alternative. Experimental work in dogs demonstrates clear functional differences between colon and jejunum as free oesophageal grafts, and shows how structurally and functionally the colon integrates into the new position in the oesophagus better than the jejunum.

Animals↗
PubMed1987

Relocation of nonalbumin proteins after albumin resuscitation.

Prior work showed that albumin (5% A) resuscitation lowered serum globulins and coagulation protein activity levels compared to balanced electrolyte solution (BES) resuscitation. In this experiment, the effect of 1.25% A in BES (A-BES) on serum and lymphatic levels of nonalbumin proteins was studied in 20 splenectomized dogs subjected to reservoir shock and then treated with (a) BES or A-BES, (b) shed blood, and (c) autogenous bank blood. Serum levels of albumin, globulin, and coagulation protein activity were measured preshock, postshock, and daily for 3 days; skin lymph levels were measured on Day 3. Compared to BES, A-BES resuscitation significantly decreased serum globulins and coagulation protein activity of fibrinogen, Factor VIII, and antithrombin III. In contrast, skin lymph globulins and coagulation protein activity levels increased significantly with A-BES compared to BES resuscitation. These data suggest that the serum protein changes seen with albumin-supplemented resuscitation result from extravascular relocation of nonalbumin proteins, possibly, due to an oncotic homeostatic factor.

Animals↗
PubMed1987

Dual fluorometric/colorimetric detection system for an automated random-access instrument utilizing standard polystyrene test tubes as precision cuvettes.

To attain the optical precision necessary to precisely quantify fluorescent or colorimetric signals, analytical systems have typically included quality-controlled cuvettes, flow cells, or dual-beam reference systems. We describe a system where a fluorescence or transmittance signal is quantified in single, standard, 12-mm-diameter polystyrene test tubes. Tube-to-tube variation is minimized by referencing the primary signal to a second reference signal. The tube is carefully oriented within a positioner that allows for the precise placement of the tube within a light path 7.6 mm in diameter. The detection system allows for use of either four pairs of fluorescence excitation/emission wavelengths or eight transmittance wavelengths, which are selected by using specific interference filters. The impact of temperature, tube imperfections, surface flaws, and distortions is minimized by using a reference ratio. Fluorescence is measured with an orthogonal photomultiplier tube, and transmittance with a photodiode; both are illuminated with an ordinary long-life tungsten-halogen lamp. This system is used with the Becton Dickinson AFFINITY system, an automated random-access analyzer with analyte-specific unit-package reagents. The polystyrene tube of the reagent package, which has an antibody-absorbed surface, serves as both the cuvette and the separation medium. Use of the reference ratio method reduces intertube imprecision of fluorometric or transmittance signals, for more precise quantification of various analytes.

Autoanalysis↗
PubMed1986

Disposition of 2,4-dinitroaniline in the male F-344 rat.

The disposition and metabolism of 2,4-dinitroaniline was studied in male F-344 rats following oral and i.v. administration. Gastrointestinal absorption was near complete and was not affected by dose (10-90 mumol/kg). Following either oral or i.v. administration, dinitroaniline was rapidly distributed throughout the tissues and showed no marked affinity for any particular tissue. 14C-dinitroaniline was readily cleared by metabolism to at least nine metabolites; radioactivity was excreted primarily in urine (70% dose) and to a lesser extent in faeces (25-30% dose). Clearance of radioactivity from the body was near complete in 3 days. As the whole-body half-life of dinitroaniline derived radioactivity in the rat was less than 3 h and there was no evidence for saturation of any mechanism of absorption, distribution, metabolism or excretion in the dose range studied, 2,4-dinitroaniline appears to have little potential for bioaccumulation in animal tissues. Analysis of urine and bile detected nine metabolites of 2,4-dinitroaniline. The major metabolite was excreted in urine as a sulphate conjugate and in bile as a glucuronide. This metabolite was characterized by combined h.p.l.c./mass spectrometry as 2,4-dinitrophenylhydroxylamine.

Administration, Oral↗