Biomedical subjects

David W Olson

Publications and source records attributed to David W Olson.

5 recordsLinked to original sources

PubMed2003

Human small bowel storage: the role for luminal preservation solutions.

BACKGROUND: Graft injury incurred during periods of cold storage remains a factor affecting the success of small bowel (SB) transplantation. No one preservation solution, including the gold standard University of Wisconsin (UW) solution, has been able to maintain graft integrity for storage periods paralleling that of other commonly transplanted intra-abdominal organs. We investigated the role for the luminal administration of preservation solutions in a small animal model, documenting significantly improved graft quality. The current study addresses direct clinical applicability using human SB. METHODS: Human SB was obtained at the time of standard multiviscera procurement. After a common intra-arterial UW flush, the SB was immediately removed from the abdomen, randomly divided into three segments, and treated as follows (n=6-9): group 1, no luminal flush; group 2, luminal flush with UW solution; and group 3, luminal flush with an amino acid- enriched solution. Analysis of cellular energetics, permeability, and histologic injury was performed throughout 24 hr of cold storage. RESULTS: Mucosal barrier function, measured by mannitol permeability, was significantly better overall in groups 2 and 3, with 24-hr values measuring 31 and 34 nmol/cm2/hr versus 57 nmol/cm2/hr, respectively (both P<0.05). Significantly less morphologic injury was also noted in the luminally treated specimens (groups 2 and 3) compared with the clinical standard (vascular flush with UW solution). Damage in group 1 reached gross villus denudation with an obvious elevated risk of villus tissue loss, whereas groups 2 and 3 only exhibited epithelial clefting to varying degrees. CONCLUSION: This study supports luminal administration of preservation solutions for improvement of human SB graft quality during clinically relevant periods of cold storage.

Adenosine↗

PubMed2003

Intestinal decontamination using povidone-iodine compromises small bowel storage quality.

BACKGROUND: Povidone-iodine (PI) (Betadine, Purdue Fredrick Co., Norwalk, CT) is used during pancreas transplantation to provide duodenal decontamination without any intestinal complications. METHODS: This study assessed the combined effect of a luminal pretreatment with PI followed by a proven amino acid (AA)-rich preservation solution on small bowel (SB) storage quality. Rat SB was procured using intra-arterial University of Wisconsin solution followed by luminal administration with combinations of AA+/-PI pretreatment as follows: group 1, 20 mL AA solution; group 2, 20 mL PI and 20 mL AA solution; group 3, 100 mL AA solution; and group 4, 20 mL PI and 100 mL AA solution. Cellular energetics, permeability, and histology were analyzed throughout 10-hr cold storage. RESULTS: After 10 hr, adenosine triphosphate levels remained 2.9 to 3.2 micromol/g protein lower in the PI-treated groups than in groups 1 and 3. Functional parameters were also negatively affected by PI treatment. Mannitol permeability was 203 and 66 nmol/cm2 per hr in groups 2 and 4 versus 46 and 44 nmol/cm2 per hr in groups 1 and 3. Median grades of histologic injury (Park's) at 10 hr were 3, 5.5, 4, and 5 for groups 1 through 4, respectively. Luminal flushing with PI or AA solution resulted in an equivalent clearance greater than 95% of enteric bacteria present. CONCLUSIONS: hort-duration luminal PI exposure potentiates SB injury and provides no improved intestinal decontamination.

Animals↗

PubMed2002

Potentiating the benefit of vascular-supplied glutamine during small bowel storage: importance of buffering agent.

BACKGROUND: Glutamine (gln)-supplemented University of Wisconsin (UW) solution improves overall small bowel (SB) preservation. Sustained gln metabolism in a system devoid of hepatic detoxification will necessarily result in the accumulation of pH active end products leading to nonphysiologic pH shifts. We hypothesized that simultaneous addition of N,N-bis[2-hydroxyethyl]-2-aminoethane sulfonic acid (BES), a known buffering agent, would potentiate the beneficial effect of gln supplementation by addressing the fundamental metabolic principle of pH homeostasis. METHODS: Sprague-Dawley SB rats were administered a vascular flush with one of four solutions: UW; UW+90 mM BES (UWB); UW+2% gln (UWG); or UW+2% gln+90 mM BES (UWBG). Indices of energetics, barrier function, gln catabolism, and histology (light and electron microscopy) were assessed over a 10-hr cold storage time course. RESULTS: Superior gln utilization in the UWBG group was indicated by elevated levels of key catabolites (glutamate, aspartate, glycine, ammonia). The addition of BES and gln resulted in significantly higher levels of all energetic parameters (ATP, total adenylates) at 10 hr compared with UW, UWB, and/or UWG. Barrier function was markedly improved after 10 hr storage in the UWBG group; mannitol permeability was 169 nmol/cm2/hr versus 572 and 445 nmol/cm(2)/hr (for UW and UWG, respectively). Histologic injury at 10 hr was 5.5, 7.5, and 8 (Park's grade) for UWBG, UWG, and UW. Ultrastructural damage was markedly reduced with UWBG, as assessed by grade of mitochondria damage. CONCLUSION: This study strongly supports that the beneficial effects of gln-enriched UW solution can be amplified when combined with an effective buffering agent such as BES.

Adenosine↗

PubMed2002

Defining the role of a tailored luminal solution for small bowel preservation.

The mucosal layer is the initial site of small bowel (SB) graft injury sustained during cold storage. Vascular administration of preservation solutions alone is unable to prevent ischemic injury of this layer during clinically relevant storage periods. The SB is unique in that it possesses both a vascular and a luminal route by which preservation solutions can be administered. We hypothesized that addition of a luminal-delivered solution, formulated on amino acid requirements for energy- and non-energy-related reactions, would provide site-specific preservation of mucosal energetics, barrier function and morphology throughout an extended period of cold storage. Of the three luminal solutions containing amino acids which were tested (UWG, AA1, AA2), only the two groups (AA1, AA2), containing glutamine plus 18 other amino acids, +/- osmotic agent (lactobionate) and buffer (BES), exhibited significant improvements in energetics, barrier function, and histology compared to the clinical standard of isolated vascular University of Wisconsin (UW) solution. Although the AA1 and AA2 groups preserved barrier function and morphology up to 24h better than all other solutions tested, AA2 proved to be the only luminal solution with values of permeability, conductance, and short-circuit current not significantly different from freshly isolated tissues. Furthermore, the greatest reduction in histologic injury was effected by AA2 treatment (median grade 2 compared to control, UW(v), grade 8). This study documents that a luminal-delivered solution, formulated on physiologic SB requirements, provides targeted preservation of the SB mucosa.

Adenine Nucleotides↗

PubMed2002

How long do patients wait for elective general surgery?

OBJECTIVE: Because data published on waiting times are largely determined from questionnaire-type surveys, which generate inconclusive opinion-based results, the objective of this study was to provide a quantitative measure of the extent and variance of waiting times among 3 elective general surgery procedures DESIGN: A prospective case study. SETTING: The Royal Alexandra Hospital, Edmonton. PATIENTS: From Feb. 1 to Mar. 15, 1999, all cases (90 patients) for each designated procedure--open or laparoscopic cholecystectomv for biliary colic or cholelithiasis, segmental resection or modified radical mastectomy for breast carcinoma and colon or rectal resection for colorectal carcinoma--were tabulated daily from the hospital elective operating lists. Data were prospectively acquired from individual surgeon offices (11 surgeons). Sixteen of the 90 patients were excluded, leaving 74 for analysis. OUTCOME MEASURES: Time in days from initial referral by the general practitioner to the surgeon (T1), time in days from the initial visit with the surgeon to operation for patients requiring no further diagnostic work-up by the surgeon (T2A), and time in days from the initial visit with the surgeon to operation for patients requiring further diagnostic work-up (T2B). RESULTS: The waiting period for patients who underwent non-cancer-related procedures (cholecystectomy) ranged from 83 to 106 days; patients with breast cancer waited an average of 24 (T1 + T2A) to 66 (T1 + T2B) days from the day of referral to the date of surgery and those with colorectal cancer waited an average of 32 (T1 + T2A) to 51 (T1 + T2B) days from the time of referral to operation (p < 0.05). CONCLUSION: This preliminary report aimed at quantitative measurement of time spent waiting for elective general surgery indicates that patients who underwent non-cancer-related procedures waited significantly longer for their surgery than patients who required procedures for cancer.

Alberta↗