PubMed Health⌕ Search

Biomedical subjects

H Asbun

Publications and source records attributed to H Asbun.

8 recordsLinked to original sources
PubMed1991

Safe performance of difficult laparoscopic cholecystectomies.

Laparoscopic cholecystectomy has been advocated for the treatment of uncomplicated symptomatic gallstone disease, but has not been widely advocated for the management of more complicated gallbladder disease such as acute cholecystitis, previous surgery, or common duct stones. During the last 9 months, 360 patients underwent laparoscopic removal of their gallbladder. A total of 138 had a complicated presentation, making surgery more difficult. This article discusses the management of these patients with acute cholecystitis, previous surgery, or common duct disease. Using the described techniques, there were no complications or mortality. Laparoscopic management of difficult gallbladder problems is safe and effective.

Acute Disease↗
PubMed1990

Uncoupling of sodium chloride transport in premalignant mouse colon.

Ion transport across premalignant large bowel mucosa in CF1 mice was evaluated by measuring sodium and chloride fluxes across voltage-clamped colonic segments obtained from control animals and animals treated for 4 wk with the procarcinogen 1,2-dimethylhydrazine, which induces tumor development principally in the distal colon. In control CF1 mouse colon, the net flux of sodium was 5.1 +/- 0.7 and 4.6 +/- 0.7 microEq.cm-2.h-1 and the net flux of chloride was 6.1 +/- 1.3 and 0.8 +/- 1.2 microEq.cm-2.h-1 in the distal and proximal colon, respectively. Removal of bicarbonate decreased the net flux of sodium 1.5 +/- 0.5 and 1.9 +/- 0.7 microEq.cm-2.h-1 in the distal and proximal colon, respectively, while the net flux of chloride was decreased to 1.7 +/- 1.8 microEq.cm-2.h-1 in the distal colon but was unaltered (0.8 +/- 0.1 microEq.cm-2.h-1) in the proximal colon. Addition of 25 mM bicarbonate stimulated the net flux of sodium and chloride absorption in the distal colon but increased net flux of sodium absorption alone in the proximal colon and stimulated net flux of chloride secretion. Removal of chloride decreased net flux of sodium to 3.4 +/- 1.4 and 1.8 +/- 0.8 microEq.cm-2.h-1 in the distal and proximal colon, respectively. Addition of 20 mM Cl stimulated net flux of sodium in the distal but not the proximal colon. These data suggest that sodium absorption is mediated by an electroneutral Cl-dependent, HCO3-dependent process (i.e., Na-H Cl-HCO3 dual exchange) in control distal colon and by an electroneutral HCO3-dependent process in control proximal colon. Following 1,2-dimethylhydrazine treatment, net flux of sodium in the distal colon was not stimulated by the addition of Cl or HCO3, and transport in the proximal colon was similar to that in control animals. However, 1,2-dimethylhydrazine treatment appears to uncouple Na-H Cl-HCO3 exchange in the distal colon early in the process of large bowel carcinogenesis.

1,2-Dimethylhydrazine↗
PubMed1989

Detection of the cancer-prone colon, using transepithelial impedance analysis.

Alterations in ionic conductance may represent an early mitogenic signal; therefore, impedance analysis was used to examine differences in the electrical properties of the distal colon in a cancer-susceptible (CF1) and a cancer-resistant (DBA) strain of mouse following administration of the carcinogen dimethylhydrazine. The electrical conductance of the surface colonic epithelium increased in CF1 mice from a mean (+/- SEM) of 41.1 +/- 3.0 milliSiemens.cm-2 (mS.cm-2) in controls to 52.6 +/- 3.1 mS.cm-2 following dimethylhydrazine treatment. The conductance decreased in the cancer-resistant DBA group from 154.6 +/- 44.1 mS.cm-2 in controls to 35.1 +/- 17.2 mS.cm-2 following dimethylhydrazine treatment. This difference in response to the carcinogen may partly explain differences in susceptibility noted between these two species. Epithelial impedance analysis may be of use in the early detection of the colon at risk for subsequent cancer development.

Animals↗
PubMed1989

The electrical and sodium transport characteristics of sutured premalignant mouse colon.

Depolarization of the plasma membrane and increased sodium influx have both been suggested as mitogenic signals. Following bowel resection the intestinal suture line has been reported a fertile site for tumor recurrence. Whether alterations in cell surface signaling occur at suture lines has not been previously examined the electrical changes of sodium transport occurring at a suture line in an animal model of large bowel cancer. Forty-eight female CF1 mice underwent colotomies with repair utilizing silk or chromic sutures. Twenty-four mice underwent sham operations to serve as controls. The mice were injected subcutaneously with the carcinogen DMH (1,2-dimethylhydrazine) 20 mg/kg or an identical volume of 0.9% saline for 6 weeks and were sacrificed 1 week after the last injection. The sites of the sutured colotomies or a piece of distal colon from the sham-operated mice were mounted in a modified Ussing chamber and the electrical properties and unidirectional sodium fluxes were measured. The potential difference (pd) across the distal colon was not significantly different in any suture group compared to that in sham-operated controls when treated with saline (pd sham, -2.3 +/- 0.2 mV (mean +/- SEM); silk, -1.7 +/- 0.3 mV, chromic, -1.9 +/- 0.3 mV, P greater than 0.05, unpaired Student t test). The potential difference was significantly lowered in both suture groups compared to sham operated animals after treatment with DMH (pd sham, -2.6 +/- 0.3 mV; silk, -1.5 +/- 0.2 mV, P less than 0.05; chromic, -1.6 +/- 0.4 mV, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

1,2-Dimethylhydrazine↗
PubMed1987

Epithelial impedance analysis in experimentally induced colon cancer.

Epithelial impedance analysis was used to measure the alterations in resistance of the large bowel in a murine model of large bowel cancer. The technique was able to resolve the epithelial resistance from the total resistance of the bowel wall. A progressive decrease in resistance of the bowel epithelium occurs during carcinogenesis induced with dimethyhydrazine. About a 21% decrease in epithelial resistance from 22.0 +/- 1.3 omega.cm-2 to 17.5 +/- 1.1 omega cm-2 (p less than 0.025) was observed after 20 wk of carcinogen administration. The sensitivity of the technique in detecting altered epithelial resistance in premalignant bowel mucosa was improved by examining the impedance profile in a sodium-free Ringer's solution where the epithelium of control colons had a resistance of 24.4 +/- 1.8 omega.cm-2 compared with 19.0 +/- 1.1 omega.cm-2 (p less than 0.02) in colons from animals treated for only 4 wk with the carcinogen. Epithelial impedance analysis would seem to be a sensitive technique capable of identifying changes in the electrical properties or the large bowel early in disease states.

Animals↗
PubMed1986

Colonic epithelial impedance analysis in a murine model of large-bowel cancer.

Death rates from large-bowel cancer have remained essentially unchanged over the past 40 years because the diagnosis is made late, after the tumor has spread to other sites. This study was undertaken to examine whether alterations in mucosal electrical capacitance precede the development of gross malignancy, since this parameter may reflect functional or structural changes in the colonocyte plasma membrane, which is of importance in the regulation of cell growth. Distal colonic mucosal capacitance was decreased at low frequencies after only four weeks of treatment with the carcinogen dimethylhydrazine in C1 mice. Alterations in electrical capacitance may be a useful marker in identifying patients with a propensity to develop large-bowel cancer.

Animals↗