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Biomedical subjects

G Olofsson

Publications and source records attributed to G Olofsson.

13 recordsLinked to original sources
PubMed2002

In vitro determination of active bile acid absorption in small biopsy specimens obtained endoscopically or surgically from the human intestine.

BACKGROUND: In the construction of a Kock reservoir for continent urinary diversion, 70 cm of the distal ileum are used. Impaired absorption of bile acids in these patients might cause diarrhoea. Data on the absorption of bile acids in different parts of the human intestine are limited. METHODS: Biopsies were taken during endoscopy from the duodenum, the terminal ileum or the right colon, and during surgery 10, 50, 100 and 150 cm proximally to the ileo-caecal valve using standard endoscopy biopsy forceps. The biopsy specimens were incubated in vitro with radio-labelled taurocholic acid at 37 degrees C for 22 or 45 min The radioactivity was determined using the liquid scintillation technique. RESULTS: A linear increase in the uptake was observed, with increased concentrations of taurocholic acid between 100 and 500 microm in all specimens tested, that represented passive uptake or unspecific binding. The active uptake could be calculated from the intercept of the line representing passive uptake with the ordinate. The active uptake in the terminal ileum was 3-4 times greater than 100 cm proximal to the valve. CONCLUSIONS: The active absorption of bile acids in humans can be determined in small biopsy specimens taken using standard biopsy forceps during endoscopy or surgery. This method is suitable for clinical studies of bile acid absorption. Active uptake of bile acids not only takes place in the very distal part of the ileum but also to a considerable degree 100 cm proximally to the ileo-colonic valve. This should be taken into account when selecting the ileal segment for continent urinary diversion.

Adult↗
PubMed2001

Vitamin B12 metabolism after urinary diversion with a Kock ileal reservoir.

OBJECTIVE: To elucidate the influence of construction of a Kock reservoir for urinary diversion using 70 cm of the distal ileum on vitamin B12 metabolism. MATERIAL AND METHODS: Blood samples for determination of cobalamin concentrations were drawn up to 18 years after construction of a Kock reservoir in 97 patients. Preoperative values were obtained in 20 of these patients. Pre- and postoperative Schilling tests and analyses of methylmalonic acid and homocysteine concentrations were performed in subgroups. RESULTS: The operation did not induce a significant decrease in cobalamin uptake as reflected in the pre- and postoperatively performed Schilling tests. No significant decline in cobalamin concentration postoperatively was noted. The value of analysis of methylmalonic acid and homocysteine concentrations in finding patients with cobalamin deficiency is limited by the fact that kidney function influences the results. Ten per cent of the patients did develop true cobalamin deficiency. A postoperative vitamin B12 value below 200 pmol/l indicates a 50% risk of later cobalamin deficiency. CONCLUSIONS: The construction of a Kock reservoir does not per se cause cobalamin deficiency. Substitution should be instituted at a postoperative concentration below 200 pmol/l.

Adult↗
PubMed2001

Long-time experience with the Kock ileal reservoir for continent urinary diversion.

OBJECTIVES: N.G. Kock performed the first continent cutaneous ileal reservoir for urinary diversion in 1975 at the Sahlgrenska University Hospital, Göteborg, Sweden. We have investigated the fate of the patients operated during the following 25 years at this hospital and analyzed their health-related quality of life (SF-36) as well as their psychological adjustment to a life with a continent urinary reservoir (OAS). MATERIAL AND METHODS: Between 1975 and 1999, 176 patients underwent continent urinary diversion using a Kock reservoir. At the end of 1999, 126 patients were known to be alive. Their reservoir function was estimated from their journals as well as from a questionnaire answered by the patients. RESULTS: Almost 90% of the survivors had a well-functioning reservoir at the time of follow-up. The need for reoperation has been high, mainly due to nipple problems. Kidney function is not influenced by the continent diversion per se. The health status of the patients is more influenced by the underlying disease than by their reservoirs. Patients with benign functional or inflammatory diseases experience comparatively more problems with their reservoirs. CONCLUSIONS: The functional end results as well as patient acceptance of continent urinary diversion with a Kock reservoir are excellent.

Adult↗
PubMed2000

Phase transition in dioctadecyldimethylammonium bromide and chloride vesicles prepared by different methods.

The gel to liquid crystalline phase transition of the double-chained cationic dioctadecyldimethylammonium chloride and bromide (DODAX, X = Cl- or Br-) in aqueous vesicle dispersions prepared by non-sonication. sonication and extrusion has been investigated using high-sensitivity differential scanning calorimetry (DSC). The transition temperature (Tm) is a function of the preparation method, amphiphile concentration, vesicle curvature and nature of the counterion. DSC thermograms for DODAB and DODAC non-sonicated vesicle dispersions exhibit a single endothermic peak at Tm roughly independent of concentration up to 10 mM. Extrusion broadens the transition peak and shifts Tm downwards. Sonication, however, broadens slightly the transition peak and tends to shift Tm upwards suggesting that extrusion and sonication form vesicles with different characteristics. DODAC always exhibits higher Tm than DODAB irrespective of the preparation method. Tm changes as follows: Tm (sonicated) > or = Tm (non-sonicated) > Tm (extruded). Hysteresis of about 7 degrees C was observed for DODAB vesicle dispersions.

Bromine↗
PubMed1998

Bile acid malabsorption after continent urinary diversion with an ileal reservoir.

PURPOSE: We determine the effect of urinary diversion with a Kock ileal reservoir on bile acid absorption and bowel habits. MATERIALS AND METHODS: We asked 96 patients with a Kock ileal urinary reservoir to record bowel habits and abdominal symptoms for 1 week. Data on 75 patients were further analyzed. Bile acid absorption was determined in 29 healthy control subjects, in 17 before and 6 months after continent urinary diversion, and in 21, 2 to 14 years postoperatively. Bile acid absorption was considered pathological when retention of less than 10% of an oral capsule containing selenium-75 labeled tauroselcholic acid (SeHCAT) was noted after 1 week. RESULTS: Mean number of defecations plus or minus standard deviation was 9.4 +/- 6.1 (75 cases). Of the patients 13% had 15 or more stools per week and 15% complained of always having loose stools. Mean value for the SeHCAT test was 32 +/- 19% preoperatively and 17 +/- 16% 6 months postoperatively (p = 0.0023). The corresponding value for healthy controls was 39 +/- 18%. Significant relationships were found between the results of the SeHCAT test postoperatively, and the number of stools per week and consistency of the feces. All patients with more than 10 defecations per week had a pathological SeHCAT test. CONCLUSIONS: Most patients with an ileal urinary reservoir have fairly normal bowel habits. Bile acid absorption is significantly reduced postoperatively and approximately a third of the patients have a pathological SeHCAT test. Preoperative investigation of bowel habits is recommended and a SeHCAT test should be performed in patients with frequent, loose defecations. Other types of diversion should be offered when preoperative retention is below 10 to 20% especially in patients with impaired anal control.

Absorption↗