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Biomedical subjects

I Rasmussen

Publications and source records attributed to I Rasmussen.

At least 19 recordsLinked to original sources
PubMed2002

Renal hemodynamics during carbon dioxide pneumoperitoneum: an experimental study in pigs.

BACKGROUND: Laparoscopic living donor nephrectomy is increasingly being performed, although the effects of carbon dioxide pneumoperitoneum (CO2 PP) on renal function and hemodynamics and the levels of vasopressin are not well studied. METHODS: Renal blood flow, renal venous pressure, urine output, and vasopressin concentrations in renal venous blood were measured in pigs subjected to 12 mmHg of CO2 PP for 150 min. RESULTS: Renal blood flow was decreased at induction of PP and increased during the first 30 min after exsufflation. Renal venous pressure was increased during PP. There was indirect evidence of a decrease in urine output during PP. No changes in renal venous vasopressin concentrations were seen. CONCLUSION: A CO2 PP of 12 mmHg causes changes in renal hemodynamics and urine output. No changes in vasopressin levels were seen in this pig model, suggesting that other explanations for the observed changes must be sought.

Animals↗
PubMed2001

Ultrasound-guided percutaneous cholecystostomy in high-risk surgical patients.

BACKGROUND AND AIMS: In critically ill patients, cholecystectomy is associated with a high mortality rate. The aim of this study was to evaluate the safety, efficacy and long-term outcome of ultrasound-guided percutaneous cholecystostomy (USGPC) in critically ill patients with acute cholecystitis. MATERIALS AND METHODS: Clinical records of 51 patients, all considered high-risk surgical patients, with acute cholecystitis treated with USGPC between 1987 and 1999, were retrospectively reviewed. Response was defined as improvement in clinical symptoms and signs, and/or reduction in c-reactive protein and white blood count levels within 72 h. Long-term results were evaluated by means of clinical records and written correspondence. RESULTS: Gallbladder stones were seen in 28 patients whereas 23 had acalculous cholecystitis. Ninety percent showed clinical improvement after USGPC. Cholecystectomy was performed in 16%, of which 6% after recurrent cholecystitis. Recurrence of cholecystitis occurred in 22%. Hospital mortality was 16%. None of the deaths was procedure related or related to acute cholecystitis alone. Major complications relating to the USGPC were rare (4%), while minor catheter-related complications were quite common. CONCLUSIONS: USGPC is a procedure with few complications and a high success rate. In patients with acalculous cholecystitis as well as in many patients with calculous cholecystitis, no further treatment was needed.

Aged↗
PubMed2001

Trimethoprim-sulphamethoxazole and metronidazole as prophylaxis in colorectal surgery: a study of bioavailability after an oral single dose.

OBJECTIVE: To evaluate oral single dose prophylaxis in colorectal surgery. DESIGN: Prospective study. SETTING: University hospital, Sweden. SUBJECTS: 24 patients (13 women; 11 men; mean age 57 years, range 27-81) listed for elective colorectal operations. INTERVENTION: At 0630 on the day of the operation all patients were given an oral dose of trimethoprim-sulphamethoxazole (TMP 160 mg and SMZ 800 mg) and metronidazole (2 g). The serum concentrations of TMP and SMZ were analysed in venous samples taken at the start and end of each operation. RESULTS: The earliest operation started at 0830 and the last finished at 1700. The median (range) serum concentrations of TMP were 1.4 (0.7-2.6) mg/L (start) and 1.3 (1.0-2.8) mg/L (end), and of SMZ 35 (15-65) mg/L (start) and 33 mg (13-70) mg/L (end). The individual values were above or equal to the minimal inhibitory concentration (TMP 0.8 mg/L; SMZ 15.2 mg/L) for relevant gram-negative species. CONCLUSION: Oral TMP/SMZ in the morning gives satisfactory serum concentrations independently of when the operation is done during the day. The regimen is simple and has the potential for being an effective alternative to intravenous prophylaxis.

Administration, Oral↗
PubMed2000

Coagulation activation after laparoscopic cholecystectomy in spite of thromboembolism prophylaxis.

BACKGROUND: The aim of this study was to determine whether laparoscopic cholecystectomy (LC), in spite of its minimally invasive nature, causes coagulation activation. METHODS: Sixty-four patients undergoing LC were included prospectively. All received either dextran or low-molecular-weight heparin (LMWH). Blood samples taken the morning of the operation and the following morning were analyzed for TAT, FM, fragment 1+2, tPA, PAI-1, vWf, D-dimer, Hb, hematocrit, and APC resistance. RESULTS: Significant increases in TAT, FM, fragment 1+2, and D-dimer were seen, whereas APC resistance, Hb, and hematocrit decreased significantly. Dextran led to a decrease in vWf and no change in tPA, whereas LMWH led to an increase in both these parameters. CONCLUSIONS: Laparoscopic cholecystectomy causes coagulation activation. There are differences in the response between patients receiving dextran and LMWH as thromboembolism prophylaxis. Since most patients are discharged the day after the operation, there could be practical as well as theoretical advantages to using dextran.

Adult↗
PubMed2000

Bacterial translocation in experimental shock is dependent on the strains in the intestinal flora.

BACKGROUND: Enteric microorganisms are responsible for a significant proportion of post-surgical infections. Intestinal mucosal injury may permit translocation of bacteria and endotoxin. This study investigates translocation in peritonitis and ischemia/reperfusion by inoculating different bacterial species into the small intestine. METHODS: Twenty-five pigs were monitored hemodynamically and divided into three groups: controls (C), ischemia/reperfusion (I/R), and peritonitis (P). Intramucosal pH (pHi) was calculated tonometrically. A perfusion tube was positioned in the ileum for inoculation of the bacterial strains. In a first study period a non-pathogenic bacterium was used, whereas Escherichia coli strains with known ability to translocate were used in a second. Blood and mesenteric lymph nodes (MLNs) were obtained for bacterial culture and endotoxin analyses. RESULTS: Mesenteric arterial blood flow and pHi decreased in groups I/R and P. Endotoxin levels increased in these groups in period 1, whereas in period 2 an increase over time was only observed in group P. No bacterial translocation to blood or MLNs occurred in period 1. In period 2 bacteria translocated to MLNs in all animals, including controls. Translocation to central and/or mesenteric venous blood was found in all groups, but mainly in I/R and P. The incidence of mucosal injury was similar in the two periods. CONCLUSIONS: Since positive blood and MLN samples were only found in period 2, we conclude that translocation of bacteria seems to be more dependent on the presence of translocating strains in the intestinal bacterial flora than on the mucosal insult.

Analysis of Variance↗
PubMed2000

Intramucosal pH and pCO(2) do not strictly correlate with intestinal energy metabolism in experimental peritonitis.

This study aimed to investigate tissue hypoxia on the cellular level in sepsis. Eighteen pigs weighing 18-27 kg were studied. Intramucosal-arterial PCO(2) gradient (PCO(2)-gap) and intramucosal pH (pH(i)) were calculated using tonometry. A blind loop of the small intestine was constructed for repeated tissue biopsies to measure intestinal energy-related metabolites and lactate concentration. Six animals served as controls. In 12 animals, faecal peritonitis was induced. Six of these animals were studied without further interventions, while the others were resuscitated with dextran to maintain cardiac index at baseline level. Untreated peritonitis caused an increase in PCO(2)-gap and a drop in pH(i). The intestinal energy metabolism was not disturbed until the end of the experimental period, with a decreased energy charge value and a moderately increased lactate concentration. In peritonitis-dextran animals, PCO(2)-gap and pH(i) remained at baseline level and the energy metabolism was not disturbed. We conclude that in peritonitis, PCO(2)-gap - like pH(i) - can be influenced by other factors than strictly anaerobic tissue metabolism.

Adenosine Triphosphate↗
PubMed1999

Intestinal blood flow and intramucosal pH in experimental peritonitis.

BACKGROUND AND AIMS: Experimental peritonitis causes gut intramucosal acidosis indicating intramucosal ischemia. However, tissue acidosis may reflect other conditions than ischemia. An increased mucosal-arterial Pco2 difference ( Pco2-gap) is suggested to be a more adequate measure of tissue ischemia than intramucosal pH (pHi). This study was performed to elucidate whether keeping cardiac index (CI) and splanchnic blood flow normal or supranormal by administration of colloids and an inotropic drug could prevent the acidosis as well as reduce the Pco2-gap. A secondary aim was to study to what degree the low pHi in peritonitis really reflects ischemia. SUBJECTS: 24 anesthetized pigs (18-27 kg) divided into four groups. MODELS: A Swan-Ganz catheter, transonic flow meters and catheters for blood sampling were applied. pHi was calculated using tonometry. Standardized fecal peritonitis was induced, except in controls. One peritonitis group was given dextran (Group P(DEX)) and another in addition dobutamine (Group PDOB) to keep CI normal or supranormal, respectively. RESULTS: After 4 h, a significant drop in pHi was found in all peritonitis groups, most pronounced in untreated peritonitis (to 7.09+/-.02). Corresponding values in Group P(DEX) and Group P(DOB) were 7.22+/-.03 and 7.22+/-.01, respectively, and in controls 7.30+/-.02. The Pco2-gap and the mucosal-arterial [H+] difference ([H+]-gap) increased significantly in untreated peritonitis but did not increase in groups given dextran and dextran + dobutamine. CONCLUSION: Maintaining CI in peritonitis attenuated the reduction in pHi and prevented the increased Pco2- and [H+]-gap. It seems justified from these data to conclude that the somewhat reduced pHi in treated peritonitis groups did not reflect tissue ischemia.

Animals↗
PubMed1997

DNA binding sites recognised in vitro by a knotted class 1 homeodomain protein encoded by the hooded gene, k, in barley (Hordeum vulgare).

The homeodomain of the knotted classes of transcription factors from plants differs from the well characterized Antp/En type homeodomains from Drosophila at key amino acid residues contributing to the DNA binding. A cDNA, Hvh21, derived from the hooded gene and encoding a full length homolog of knotted1 from maize was isolated from barley seedlings and expressed as a maltose binding protein fusion in E. coli. The purified HvH21-fusion protein selected DNA fragments with 1-3 copies of the sequence TGAC. Gel shift experiments showed that the TGAC element was required for binding and the results further indicate that the HvH21-fusion protein binds DNA as a monomer.

Amino Acid Sequence↗
PubMed1997

Hemodynamic changes in the inferior caval vein during pneumoperitoneum. An experimental study in pigs.

BACKGROUND: Laparoscopic procedures of increasing difficulty and duration are becoming more and more common. This may cause significant challenges to the circulatory system and possibly influence thrombogenicity. METHODS: Experimental study of carbon dioxide pneumoperitoneum in pigs. RESULTS: Inferior caval vein blood flow remained unchanged, whereas inferior caval vein pressure increased during pneumoperitoneum. Inferior caval vein, pulmonary, and systemic vascular resistance increased during pneumoperitoneum and remained increased after exsufflation. CONCLUSIONS: Pneumoperitoneum leads to an increased inferior caval vein pressure, which could cause a dilation of peripheral veins. The similar patterns of vascular resistance in the inferior caval vein, pulmonary artery, and systemic arteries (a gradual increase remaining elevated after exsufflation) suggest a common humoral factor or increased sympathetic nerve activity.

Animals↗
PubMed1997

Small intestinal mucosal pH and lactate production during experimental ischemia-reperfusion and fecal peritonitis in pigs.

The aim of this study was to investigate mucosal pH and lactate production in a porcine model of ischemia/reperfusion and sepsis using both tonometry and a technique for segmental intestinal perfusion. Eighteen pigs (17-23 kg) were anesthetized and mechanically ventilated. They were divided into three groups and followed for 4 h. Group C (n = 6) served as controls. In the ischemia/reperfusion group (I/R; n = 6), the superior mesenteric artery was totally occluded for 60 min. In group P (n = 6), sepsis was induced by fecal peritonitis. Cardiac index (CI) was determined by thermodilution and blood flow in the superior mesenteric artery (QSMA), using a Transonic flow probe. Intramucosal pH (pHi) was calculated using tonometry. A special balloon tube for segmental perfusion was introduced in the midileum for lactate measurement. Lactate and oxygen saturation were measured in arterial blood and in the superior mesenteric vein. CI, QSMA, pHi, and lactate in blood and perfusate remained unchanged in controls. Occlusion of intestinal blood flow induced a fall in pHi from 7.28 +/- .02 to 6.76 +/- .04, a marked rise in lactate in the perfusate, and an increased arteriovenous lactate difference. During reperfusion, pHi tended to return to baseline values. Lactate in the perfusate and the arteriovenous lactate difference decreased. In sepsis there was a continuous reduction in CI and QSMA to 45 +/- 13% and 40 +/- 20% of baseline, respectively. pHi decreased moderately from 7.22 +/- .09 to 6.98 +/- .25. Lactate remained unchanged in blood and perfusate. Microscopic mucosal injury was observed in all animals subjected to ischemia/reperfusion and in three of six pigs in group P. A good association between pHi and lactate production was seen in ischemia/reperfusion. However, in sepsis, lactate in superior mesenteric venous blood or in intestinal perfusate did not increase, despite the fall in pHi. The mechanism causing ischemic mucosal injury has different characteristics in sepsis and in ischemia caused by arterial occlusion.

Animals↗
PubMed1997

Incidence of thromboembolic complications after laparoscopic cholecystectomy: review of the literature.

The purpose of this study was to quantify the risk of thromboembolic complications after laparoscopic cholecystectomy by a survey of the literature. We reviewed 60 laparoscopic cholecystectomy series consisting of 153,832 patients. The average mortality was 0.08%. The average rate of fatal pulmonary embolism was 0.02% and total pulmonary embolism 0.06%. The average rate of reported deep vein thrombosis was 0.03%. We conclude that laparoscopic cholecystectomy is a safe procedure, and the rate of clinically evident postoperative thromboembolic complications is probably lower than after conventional cholecystectomy. A lingering bias due to the overrepresentation of young and healthy patients early in the era of laparoscopic cholecystectomy could, however, still affect these figures. An underreporting of the lesser complications is likely. The risk is not negligible, though, and some authors have recommended thromboembolism prophylaxis, although further studies are necessary to find the optimal prophylaxis strategy. The true incidence is possible to establish only by using objective diagnostic methods for surveillance.

Cholecystectomy, Laparoscopic↗
PubMed1997

An experimental porcine model of partial ischaemia of the distal colon.

OBJECTIVE: Ischaemia of the colon is a major challenge in aortoiliac surgery. The aim was to establish an animal model of partial distal colonic ischaemia to study interventional strategies. DESIGN: Randomised experiment. SETTING: University Hospital. Department of Experimental Research. MATERIAL: 19 pigs. INTERVENTIONS: 11 Pigs were subjected to ischaemia consisting of total occlusion of the inferior mesenteric artery and partial occlusion of the superior mesenteric artery. Eight animals were sham controls. Dextran was given. MAIN OUTCOME MEASURES: Haemodynamic measurements, intramucosal pH-measurements (pHi) and histological grading. RESULTS: Both ischaemic animals and controls remained haemodynamically stable. It was possible to maintain stable ischaemia in the distal colon in the pHi-range of 6.9-7.1. There was histological mucosal damage of the distal colon in ischaemic animals but not in controls. CONCLUSIONS: The model could be of value when studying interventional strategies to reduce or reverse ischaemia.

Animals↗
PubMed1996

Teaching reading to disabled readers with language disorders: a controlled evaluation of synthetic speech feedback.

In a long-term study two groups of language and reading impaired students (N = 15 + 15) were reading with the aid of segmented speech-feedback in a computerized program. One group received feedback that was simultaneously segmented visually and auditorily into syllables, the other received feedback by letter names. In both groups subjects were expected to synthesize segments into words and to compare their synthesis to whole word feed-back subsequently provided by the computer. They worked for half a lesson (approximately 20 minutes) a day for a total of 40 days. During this period the experiment groups progressed more in reading than a control group of age and reading-level-matched students (N = 35) who received traditional remedial instruction. The group in the syllable condition gained slightly more in non-word reading and in syllable segmentation than did the letter group. Differences in gains in reading abilities were not explained by differences in age, but to some extent by initial level of phoneme and syllable awareness. Future applications of the speech-feedback system are discussed.

Achievement↗
PubMed1996

The management of liver cell cancer.

Hepatocellular carcinoma (HCC) is a highly malignant tumour. It presents a considerable management problem. In this review the natural history of HCC is summarized. Surgical and non-surgical treatment modalities are reviewed. Finally, combined treatments are described.

Antineoplastic Agents↗
PubMed1995

Changes in gut intramucosal pH and gut oxygen extraction ratio in a porcine model of peritonitis and hemorrhage.

OBJECTIVE: To establish the relationship between gut intramucosal pH and blood flow to the gut, gut oxygen delivery, and gut oxygen extraction ratio in a porcine model of peritonitis and hemorrhage. DESIGN: Prospective, controlled study. SETTING: Experimental laboratory in a university teaching hospital. SUBJECTS: Thirty pigs of both sexes, weighing 15 to 22 kg. INTERVENTIONS: Animals were anesthetized, intubated, and mechanically ventilated. A flow probe was placed around the superior mesenteric artery for registration of blood flow. A tonometer was placed in the lumen of midileum for calculation of gut intramucosal pH. Hourly, for 5 hrs, blood samples were taken from mixed venous, mesenteric venous, and arterial blood. Five animals served as controls, ten animals had peritonitis induced by fecal instillation in the abdominal cavity, five were bled stepwise, five were bled rapidly (to a mean arterial pressure of 30 mm Hg), and five were bled rapidly and reinfused after 3 hrs. MEASUREMENTS AND MAIN RESULTS: Both peritonitis and hemorrhage caused decreases in gut blood flow and intramucosal pH. In mild peritonitis, the intramucosal pH decrease preceded that of blood flow. In all experimental groups, oxygen delivery decreased over time; in both mild and severe peritonitis, this decrease was preceded by a decrease of intramucosal pH. Intramucosal pH correlated well with gut oxygen extraction ratio in peritonitis (r2 = .86). In hemorrhage, there was a correlation of r2 = .66, but in intramucosal pH of < 7.12, a further decrease was accompanied only by minor changes in extraction ratio. CONCLUSIONS: Since a reduction in blood flow was preceded by a decrease in intramucosal pH, low intramucosal pH in peritonitis cannot be explained by low flow alone. Gut oxygen delivery proved to be a poor indicator of gut acidosis (i.e., low intramucosal pH). In peritonitis, a decreasing intramucosal pH was associated with an increasing oxygen extraction ratio. In hemorrhage, this association had a sharp deflection point below which a further decrease in intramucosal pH occurred concomitantly with an unchanged gut oxygen extraction ratio. Increased extraction ratio was not sufficient, not even initially, to maintain aerobic metabolism (i.e., unchanged intramucosal pH).

Animals↗
PubMed1995

Hepatic extraction of hyaluronic acid in porcine peritonitis.

The hepatic extraction of hyaluronic acid (HA) was studied in porcine fecal peritonitis in two groups of animals given various amounts of volume substitution. There was a progressive decrease in hepatic blood flow (QH) and a corresponding increase in the plasma concentration of HA in arterial blood over a 5-hour observation period, less pronounced in animals given more volume substitution. While hepatic clearance of HA decreased, the extraction ratio over the liver was not altered. The extracted amount of HA, which at steady state reflects the turnover of HA, was also unchanged. There was a significant correlation between QH and arterial HA concentration (r = 0.57; p < 0.05). The data suggest that the arterial HA concentration in sepsis reflects QH rather than an altered ability of the liver to eliminate HA.

Animals↗
PubMed1994

Detection of liver ischemia using microdialysis during experimental peritonitis in pigs.

The liver oxygen delivery (DO2) and consumption (VO2) were measured in a porcine model of septic shock induced by fecal peritonitis. Lactate and hypoxanthine were simultaneously monitored in hepatic extracellular fluid and in central venous blood using a microdialysis technique. Animals were divided into a control group (n = 6) and a peritonitis group (n = 6). Peritonitis was induced by installation of a standardized amount of autologous feces into the abdominal cavity. The animals were followed for 5 h. The changes in the liver during peritonitis were, a decreased DO2, a increased, maintained, or decreased VO2, an increased oxygen extraction, and a loss of net hepatic lactate uptake. Parallel to these changes, systemic lactic acidosis developed. Intrahepatic lactate and hypoxanthine increased during peritonitis reflecting liver ischemia. The increase of these metabolites was seen concomitantly in the liver and in central venous blood. There was a wide variability of the individual response to the septic challenge among the animals. The limited hepatic oxygen delivery, and the increased needs for oxygen led to flow-dependent oxygen consumption, and signs of liver ischemia in severe sepsis. Intrahepatic and intravenous microdialysis may be useful for monitoring of the individual time course of hepatic and systemic ischemia in sepsis.

Acidosis, Lactic↗