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Biomedical subjects

H L Young

Publications and source records attributed to H L Young.

50 records · Page 3Linked to original sources

Report of a prospective trial of dextranomer beads (Debrisan) and silicone foam elastomer (Silastic) dressings in surgical wounds.

A prospective randomized controller trial of dextranomer beads (Debrisan) and silicone foam elastomer (Silastic) dressings in open infected surgical wounds has been performed. The results indicate that the healing time for wounds treated by Debrisan (n = 25) and elastomer (n = 25) is similar, being 40.92 +/- 3.98 and 36.90 +/- 3.18 days respectively. The time taken for wounds to become pain-free was similar in both treatment groups, as was the persistence of signs in the wounds of erythema, oedema and slough. Comparison of cost reveals the elastomer dressing to be considerably cheaper than Debrisan.

Adult↗

The effect of intravenous aprotinin (Trasylol) on intraperitoneal adhesion formation in the rat.

A randomized controlled trial to assess the effect of intravenous Trasylol on postoperative intraperitoneal adhesion formation has been performed in rats. Before undergoing a standard left colonic resection, animals received i.v. Trasylol 10 000 KIU. This dose was repeated 8-hourly for 3 days postoperatively. Control animals received saline placebo. The mean percentage circumference of the anastomosis covered with adhesions in the Trasylol group animals was 20.86 +/- 6.08 compared with 45.24 +/- 5.97 in the control group (P less than 0.01). Significantly more animals treated with Trasylol were completely free of adhesions than those receiving saline. Bursting pressures did not differ between the two groups. Intravenous Trasylol clearly inhibits intraperitoneal adhesion formation in this model.

Animals↗

Fluid and electrolyte shifts during bed rest with isometric and isotonic exercise.

Fluid and electrolyte shifts were measured in seven men (19-21 yr) during three 2-wk bed rest (BR) periods, each of which was separated by a 3-wk ambulatory recovery period. During two of the three BR periods they performed isometric exercise and isotonic exercise. No prescribed exercise was given during the other BR period. On day 4 of BR, plasma volume decreased (P less than 0.05) 441 ml (-12.6%) with no exercise, 396 ml (-11.3%) with isometric, and 262 ml (-7.8%) with isotonic exercise; the decreases (NS) of extracellular volume were -4.4%, -2.6%, and -2.7%, respectively. By day 13 of BR, plasma volume stabilized at the lower level with isometric and isotonic exercise and continued to decline with no exercise; but the extracellular volume returned to or above control levels due to an overshoot of the interstitial volume of +320 to +430 ml (2.0-2.7%) that was about equal to the plasma volume loss. During BR there were isocontent losses from the plasma of protein, albumin, globulin, urea N2, uric acid, creatinine, Na, Cl, osmolarity, P, and glucose that were not influenced by either exercise regimen. However, the blood, red blood cell, and plasma volumes, and the Ca and K contents were stabilized during BR by both exercise regimens. The results suggest that during BR, preservation of the extracellular volume takes precedence over maintenance of the plasma volume, and this mechanism is independent of the effects of isometric or isotonic exercise.

Adult↗

Effects of exercise on fluid exchange and body composition in man during 14-day bed rest.

To determine the cause of the body weight loss during bed rest (BR), fluid balance and anthropometric measurements were taken from seven men (19-21 yr) during three 2-wk BR periods which were separated by 3-wk ambulatory recovery periods. Caloric intake was 3,073 +/- 155 (SD) kcal/day. During two of the three BR periods they performed supine isotonic exercise at 68% of VO2max on the ergometer for 1 h/day; or supine isometric exercise at 21% of maximal leg extension force for 1 min followed by a 1-min rest for 1 h/day. No prescribed exercise was given during the other BR period. During BR, body weight decreased slightly with no exercise (-0.43 kg, NS), but decreased significantly (P less than 0.05) by -0.91 kg with isometric and by -1.77 kg with isotonic exercise. About one-third of the weight reduction with isotonic exercise was due to fat loss (-0.69 kg) and, the remainder, to loss of lean body mass (-0.98 kg). It is concluded that the reduction in body weight during bed rest has two major components: First, a loss of lean body mass caused by assumption of the horizontal body position that is independent of the metabolic rate. Second, a loss of body fat content that is proportional to the metabolic rate.

Adult↗

Ultrastructure of Pseudomonas saccharophila at early and late log phase of growth.

The fine structure of Pseudomonas saccharophila, a soil bacterium, is similar to that of the marine Pseudomonas reported by Wiebe and Chapman. The unit membrane of the plasma membrane is clearly seen in some areas of thin sections. The ribonucleoprotein granules are distributed in the cytoplasm of the cell. Cells of P. saccharophila during early exponential phase are large, and most of them contain a large number of poly-beta-hydroxybutyrate granules. Some of the granules are quite large and occupy up to three-fourths of the cross section of the cell. Thin sections of the cells in the late log phase, however, show fewer and smaller poly-beta-hydroxybutyrate granules located in the central region of the cell. Negative-stained and freeze-fracture preparations show that the outer surface of the cell wall of P. saccharophila is covered with a large number of tiny granules and long, slender flagella. The outer surface of the plasma membrane appears to be smoother than the outer surface of the cell wall, and it also contains numerous granules. Since the outer surface of the cell wall is quite smooth in freeze-fracture preparations, the wrinkled appearance in thin sections is probably an artifact of fixation and dehydration. The poly-beta-hydroxybutyrate did not solidify at the freezing temperature used (approximately -150 C), and it was consequently pulled out in a spikelike structure during the fracturing process. P. saccharophila, under the conditions in our study, appears to multiply by the constrictive type of cell division.

Cell Division↗

Effects of valine on protein synthesis and turnover in Pseudomonas saccharophila under "nongratuitous" inducing conditions.

Under "nongratuitous" inducing conditions, in Pseudomonas saccharophila, d-and l-valine and l-isoleucine inhibit net protein synthesis. At a concentration of 0.5 mumole or greater of valine per mg of bacterial protein, net protein synthesis declined approximately 70%. The inhibitory effect of valine is proportional to the exogenous valine concentration. Studies of (14)C amino acid incorporation and (14)C amino acid release from prelabeled cells indicate that valine stimulates protein turnover.

Bacterial Proteins↗

Laser Doppler assessment of human colonic blood flow.

We have used laser Doppler flowmetry to assess human colonic blood flow in patients with healthy mucosa and in those with active proctitis. We report a significant correlation between colonic serosal laser Doppler flux readings and serosal tissue oxygen tension (n = 45: r = 0.671: p = 0.001). Mucosal blood flow was measured using the PF309 probe of a Perimed Pf2b set on 12 kHz frequency shift. There was no significant difference throughout the colon in healthy patients. The flow in rectal mucosa was significantly higher in patients with proctocolitis than in normal mucosa.

Colon↗

Evaluation of fiberoptic dermofluorometry as a means of clinically assessing tissue perfusion.

Fiberoptic dermofluorometry (FDF) transcutaneously measures fluorescence, following an intravenous injection of sodium fluorescein (NaFl), which is transmitted along a fiberoptic bundle to a photomultiplier tube and converted into dermofluorescence units (DFU). In five normal subjects studied, the plasma concentration of NaFl peaked at 5-15 minutes before decaying with first order kinetics and corresponding dermofluorescence (DF) rose to a peak between 10-20 minutes before decaying. Peak DF in the head and neck was significantly higher (P less than .001) compared to other skin sites which were similar. Application to patients (n = 16) undergoing successful lower limb revascularization showed a significant (P less than 0.01) improvement in perfusion at the foot level only. The reproducibility of FDF was poor when studied on the control limbs. We conclude that FDF does not, at present, constitute a valid measure of skin perfusion.

Adult↗