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Biomedical subjects

L B Svendsen

Publications and source records attributed to L B Svendsen.

At least 37 records · Page 2Linked to original sources
PubMed1996

Validation of transcranial near-infrared spectroscopy for evaluation of cerebral blood flow autoregulation.

The aim of the study was to evaluate a new noninvasive transcranial near-infrared spectroscopy (TNIRS) technique for determination of the lower limit of cerebral blood flow (CBF) autoregulation by comparing this technique with the standard cerebral arteriovenous oxygen saturation difference (AVDo2) method. In eight healthy volunteers, mean arterial blood pressure was increased by infusion of angiotensin and decreased by the combination of lower-body negative pressure and labetalol. For each 5-mm Hg change in mean arterial pressure, blood was sampled from the bulb of the internal jugular vein and a radial artery, and simultaneously, the oxygen saturation of hemoglobin in the brain was measured with an INVOS 3100 Cerebral Oximeter (Somanetics). The lower limit of autoregulation was then calculated by a computer using (a) AVDo2 and (b) the difference between arterial oxygen saturation and the saturation determined with the cerebral oximeter (ACDo2). The median lower limit of autoregulation determined by the two methods was 73 and 78.5 mm Hg, respectively (p > 0.05). A statistically significant correlation between relative CBF (percentage of baseline) determined with the two methods was found below the lower limit of autoregulation (1/AVDo2 = 12 + 0.8 x 1/ACDo2; r = 0.55; p < 0.001). For all the 98 pairs of saturations registered, the correlation was 0.37 (p < 0.001), the mean difference was 16%, and the limits of agreement were -2.2 and 33.8%. We conclude that the cerebral oximeter might be useful in evaluation of the lower limit of cerebral autoregulation. This method, however, is of no value for estimation of levels of global cerebral oxygen saturation.

Adult↗
PubMed1996

Hyperplastic polyposis of the large bowel. Three cases and a review of the literature.

Small hyperplastic polyps of the large bowel constitute a frequent non-neoplastic lesion, whereas large or multiple hyperplastic polyps are rare. Here we report three cases of multiple small polyps together with some large hyperplastic ones. Two of the cases had a primary carcinoma in the bowel before onset of the polyps. The neoplastic potential of the hyperplastic polyp is discussed on the basis of the most recent investigations and the three presented cases. The hyperplastic polyp does not seem to be directly involved in the adenoma-carcinoma sequence, but dysplastic changes can be found in large hyperplastic polyps. In cases of multiple hyperplastic polyps a tendency towards a more uniform distribution of the polyps throughout the large bowel is observed. Hyperplastic colonic polyps may exist as a clinical entity, and a definition based on distribution, multiplicity, size, and symptoms is proposed. Patients with multiple or large hyperplastic polyps should have colonoscopy performed at short intervals, with removal of all lesions larger than 5 mm for histologic examination.

Adenocarcinoma↗
PubMed1995

[Compartment syndrome as a postoperative complication of lithotomy position].

Surgical procedures necessitating the use of the lithotomy position can be associated with neuromuscular lesions, usually arising from compression of nerves and muscles. Compartment syndrome of the lower extremities is a grave complication which, if unrecognized, can lead to either permanent neuromuscular dysfunction or limb loss. We report two cases of compartment syndrome complicating surgery in the lithotomy position.

Adult↗
PubMed1995

[Paracetamol poisoning].

Administration of paracetamol (acetaminophen) has analgetic and antipyretic effect. After trauma paracetamol has an anti-inflammatory activity. It was presumed that paracetamol in therapeutic doses had fewer and more acceptable side-effects than other analgetic drugs such as acetylsalicylic acid and NSAID-drugs. However, in toxic concentrations, paracetamol is more life-threatening. The toxic effects of paracetamol most often occur in the liver and kidneys. Phosphate and lactate turn-over can also be impaired. Paracetamol poisoning can induce temporary liver dysfunction or even irreversible liver failure with liver transplantation as the only therapeutic possibility. Chronic alcoholics are especially at risk, as liver damage may occur following paracetamol even in recommended doses. When intoxication with paracetamol is presumed, administration of N-acetylcysteine is vital. N-acetylcysteine therapy should be initiated not later than 15 hours after paracetamol intake. Moreover, the antitoxic effect has been observed even when N-acetylcysteine therapy is initiated 24-36 hours after presumed paracetamol intake. Measures of preventing further absorbtion of paracetamol from the gastrointestinal tract should be taken. Activated charcoal should be given if less than two hours have passed since paracetamol intake. Between two and four hours following paracetamol intake gastric lavage should be performed. During the last 10 years the incidence of paracetamol self-poisoning has increased, but death following paracetamol poisoning is relatively constant at around nine per year in Denmark. It is suggested that the incidence of serious cases of paracetamol poisoning could be reduced by simple measures. Special attention should be paid to the risk-group of chronic alcoholics.

Acetaminophen↗
PubMed1995

Closure of rectal stump after colectomy for acute colitis.

In a retrospective study complications, mortality and morbidity following acute colectomy for severe colitis with intra-abdominal closure of the rectal stump were reviewed in 147 consecutive patients (71 women and 76 men, median age of 40 years, range 18-95 years). Five patients (3%) died within 30 days postoperatively; none of the deaths were related to the rectal stump. Three patients (2%) had a pelvic abscess due to leakage of the rectal closure, all were treated successfully with percutaneous drainage, guided by ultrasonography. No difficulties in locating the rectal stump or performing intended subsequent surgery were reported. The overall complications and mortality rate in this study are low and comparable to the best results reported from centers using the mucous fistula. Closure of the rectal stump is a safe procedure, and has the advantage of not leaving the patient with a second stoma.

Acute Disease↗
PubMed1995

Cimetidine as an adjuvant treatment in colorectal cancer. A double-blind, randomized pilot study.

PURPOSE: To evaluate the influence of a H2 receptor antagonist (cimetidine) on survival in patients with colorectal carcinoma, a randomized, controlled pilot study was performed in three university hospitals in Copenhagen, Denmark. METHODS: A total of 192 patients, who had undergone a resection or an exploratory operation for adenocarcinoma of the colon or rectum between May 1988 and May 1991, were enrolled in the study. After a median observation time of 40 months, outcome was noted for each patient concerning cancer-specific mortality rate. RESULTS: In patients operated with curative intent (n = 148), no difference was found in cancer-specific mortality between the two treatments. However, a tendency toward reduction in mortality rate was found in patients with curatively operated Dukes Stage C carcinoma (P = 0.11, log-rank test; difference, 29 percent; 90 percent confidence interval, 2 to 57 percent) in the cimetidine-treated group. In patients with disseminated disease no total difference was found between the two treatment groups. CONCLUSIONS: Cimetidine does not seem to reduce mortality in patients with colorectal cancer, but there seems to be a tendency toward a survival benefit in patients undergoing surgery for Dukes Stage C carcinoma. Results seem to justify trials in this patient category to reveal a benefit of H2 receptor antagonists in adjuvant therapy of colorectal carcinoma.

Adenocarcinoma↗
PubMed1995

Effect of labetalol on cerebral blood flow, oxygen metabolism and autoregulation in healthy humans.

We have studied the effects of labetalol on cerebral blood flow (CBF) and cerebral oxygen metabolism (CMRO2) in eight healthy volunteers. CBF was measured by single photon emission computerized tomography before and during infusion of labetalol. CMRO2 was calculated as CBF x cerebral arteriovenous oxygen content difference (CaO2-CvO2). CBF autoregulation was tested during infusion of labetalol by changing arterial pressure and estimating relative changes in global CBF from changes in (CaO2-CvO2). CBF before and during infusion of labetalol was 67 and 65 ml/100 g min-1, respectively (P > 0.05). CMRO2 was 2.9 and 2.8 ml/100 g min-1, respectively (P > 0.05). CBF autoregulation was preserved in all subjects. The lower limit of CBF autoregulation was 88 mm Hg (94% of baseline mean arterial pressure). We conclude that labetalol did not influence global or regional CBF, or CMRO2, and CBF autoregulation was preserved.

Adult↗
PubMed1995

Exercise-induced gastric mucosal acidosis.

Gastric acidosis as assessed by tonometry was applied to evaluate changes in splanchnic blood flow during exercise. In six healthy male oarsmen, we determined gastric acidosis in response to 30 min of maximal ergometer rowing. The gastric mucosa carbon dioxide tension was determined by equilibration of isotonic saline to the tonometer. Arterial bicarbonate (HCO3-), pH, arterial oxygen tension (PaO2), and saturation (SaO2) were obtained simultaneously, while pH (pHi) of the gastric mucosa was calculated using the Henderson-Hasselbach equation. During rowing PaO2 and SaO2 decreased to values of 73.7 mm Hg and 95.5%, respectively (P < 0.05). However, during the last minute of rowing the values were normalized with a hyperventilation reducing PaCO2 to 27.1 mm Hg (P < 0.05). Rowing decreased HCO3- from 25.8 (21.4-28.5) to 14.1 (11.6-17.4) mmol l-1, while the gastric carbon dioxide tension increased from 36.8 (24.1-63.9) to 61.7 (48.9-82.0) mm Hg (P < 0.05). Accordingly, pHi decreased from 7.25 (7.04-7.48) to 6.79 (6.67-6.85) (P < 0.05). Arterial pH also decreased (from 7.42 (7.41-7.44) to 7.29 (7.26-7.33) (P < 0.05)), with the enlarged difference between pH and pHi suggesting marked splanchnic hypoperfusion during rowing.

Acidosis↗
PubMed1995

[Paracetamol poisoning].

Administration of paracetamol (acetaminophen) has analgetic and antipyretic effect. After trauma paracetamol has an anti-inflammatory activity. It was presumed that paracetamol in therapeutic doses had fewer and more acceptable side-effects than other analgetic drugs such as acetylsalicylic acid and NSAID-drugs. However, in toxic concentrations, paracetamol is more life-threatening. The toxic effects of paracetamol most often occur in the liver and kidneys. Phosphate and lactate turn-over can also be impaired. Paracetamol poisoning can induce temporary liver disfunction or even irreversible liver failure with liver transplantation as the only therapeutic possibility. Chronic alcoholics are especially at risk, as liver damage may occur following paracetamol even in recommended doses. When intoxication with paracetamol is presumed, administration of N-acetylcysteine is vital. N-acetylcysteine therapy should be initiated not later than 15 hours after paracetamol intake. Moreover, the antitoxic effect has been observed even when N-acetylcysteine therapy is initiated 24-36 hours after presumed paracetamol intake. Measures of preventing further absorption of paracetamol from the gastrointestinal tract should be taken. Activated charcoal should be given if less than two hours have passed since paracetamol intake. Between two and four hours following paracetamol intake gastric lavage should be performed. During the last 10 years the incidence of paracetamol self-poisoning has increased, but death following paracetamol poisoning is relatively constant at around nine per year in Denmark. It is suggested that the incidence of serious cases of paracetamol poisoning could be reduced by simple measures. Special attention should be paid to the risk-group of chronic alcoholics.

Acetaminophen↗
PubMed1994

[Radiological findings in patients with a J-shaped ileal reservoir].

This study comprised 116 patients with either ulcerative colitis or familial adenomatous polyposis, who were treated from 1983 to 1990. The patients were subjected to total colectomy followed by formation of an ileoanal reservoir (J-pouch). In a retrospective study the radiological findings of the J-pouch and the reservoir related complications are presented and a description of the applied technique for pouchography is given. A total of 513 radiological investigations were performed--median two per patient (range: 1-44). All 116 patients were subjected to pouchography while 59 patients additionally underwent conventional X-ray investigations, 42 patients were referred to ultrasound and ten patients to CT. Fourty-five percent of the patients presented no radiological complications at all. Patients with a normal primary pouchogram showed a significantly lower risk of long term complications related to the pouch. Pouchography was a useful method for excluding pouch pathology before restoring intestinal continuity as well as showing fistulas or cavities. In cases of leakage and especially stenosis and pouchitis pouchography was, however, less reliable. Ultrasound examination combined with CT-scan was beneficial in diagnosing abscesses.

Adenomatous Polyposis Coli↗
PubMed1994

[Knowledge about colorectal cancer among surgeons in training].

Ninety-five participants in five theoretical courses on colorectal cancers were prior to the course asked to attend a multiple choice examination about colorectal cancer. All participants were under education in general surgery. Their experience in years as doctors was registered as was the time each participant had used for preparation before this course. For thirty-six of the participants the course ended with an examination and the participants had knowledge of that before they attended the course. We found a statistically significant relation between the amount of time spent in preparation and the results obtained in the multiple choice examination. There was no relation between results obtained and experience as a doctor. Participants who knew that an examination was to be held used significantly longer time for preparation and obtained a significantly better results than participants who did not attend any examination at the end of the course. It is concluded that the reading of text books extends the knowledge on colorectal cancer and that doctors during education are more eager to prepare when they know that an examination is waiting.

Clinical Competence↗
PubMed1994

Serum gastrin values in patients with familial adenomatous polyposis.

PURPOSE: An evaluation of the importance of gastrin in the colorectal carcinogenesis in patients with familial adenomatous polyposis was conducted. METHODS: Blood samples from 168 family members of 26 families were investigated for circulating gastrin. Blood was drawn from 65 affected patients, 66 clinically unaffected first-degree relatives, and 37 spouses. RESULTS: We did not find any difference in distribution of serum gastrin among these groups. CONCLUSION: Our results seem to exclude gastrin from being relevant in early carcinogenesis in patients with familial adenomatous polyposis.

Adenomatous Polyposis Coli↗
PubMed1993

Surveillance in hereditary nonpolyposis colorectal cancer: an international cooperative study of 165 families. The International Collaborative Group on HNPCC.

During its second meeting at Amsterdam in 1990, the International Collaborative Group on Hereditary Non-Polyposis Colorectal Cancer (ICG-HNPCC) decided to carry out a pilot study on colorectal cancer surveillance in HNPCC. The objectives of the study were to ascertain in each of the participating centers the number of HNPCC families, the recommended screening procedures, the age at diagnosis of colorectal cancer (CRC), and the occurrence of interval cancers. Nine centers in seven countries including Denmark, Finland, Italy, Japan, The Netherlands, Switzerland, and the United States participated. Data were derived from a total of 165 families. With respect to screening, half of the centers advise colonoscopy as the only procedure. The interval between the consecutive examinations varies from one to three years. In the majority of the centers, screening begins at 20 to 25 years. Lifelong screening is recommended by three centers, while the rest advise discontinuation at age 60 to 75 years. The family material included 840 patients with colorectal cancer. The mean age at diagnosis was 45 years, and about 15 percent were diagnosed at age 60 or later. A total of 682 high-risk relatives are being followed. After the follow-up of 1 to 10 years in these families, only six cases of interval cancers were encountered.

Adolescent↗
PubMed1993

Complications after J-pouch ileoanal anastomosis: stapled compared with handsewn anastomosis.

OBJECTIVE: To compare the morbidity after stapled compared with handsewn J-pouch ileoanal anastomoses. DESIGN: Retrospective study. SETTING: University Hospital, Copenhagen, Denmark. SUBJECTS: 144 consecutive patients who underwent either handsewn or stapled J-pouch ileoanal anastomosis between November 1983 and December 1991. MAIN OUTCOME MEASURES: Length of operation; operative blood loss; incidence of anastomotic breakdown, fistula and stenosis; and number of pouches that were excised as a result of complications. RESULTS: Ninety-six patients had handsewn, and 48 patients had stapled, anastomoses. There were no differences between the groups except in the length of operation (median (range) 270 (155-420) in the handsewn group compared with 197 (135-300) in the stapled group, p < 0.001), and the incidence of later stenosis of the anastomosis (22/96, 23%, compared with 3/48, 6%, p = 0.02). Patients who developed anastomotic breakdown lost significantly more blood during operation (median 2300 ml, range 1100-7500, compared with 1600 ml, range 600-6000, p = 0.02), and women were more likely to develop anastomotic leaks than men (15/70 compared with 3/74, p = 0.009). CONCLUSION: We conclude that so far the stapled anastomoses have given superior results, but it remains to be seen whether other differences will emerge as length of follow up increases.

Adolescent↗
PubMed1993

Congenital genetic instability in colorectal carcinomas.

INTRODUCTION: Oncogenic evolution is probably based on a progressive selection of clonal subpopulations from within a single clone. This selection is supposed to be based on enhanced genetic instability in the genome. In the vast majority of patients this increased lability is supposed to be the result of acquired alterations, and once established, it may contribute to the continuing, genetic instability within the neoplastic cells. It has been postulated, that inborn chromosomal instability is not limited to a few rare syndromes. Indeed, one of the common colorectal cancer (CRC) syndromes, familial adenomatous polyposis (FAP), is supposed to be a chromosomal instability syndrome. Also the hereditary nonpolyposis colorectal cancer syndrome (Lynch Syndrome (LS)) has shown genomic instability. Knudson (1971, 1985) has shown, that the same gene can be involved in both the hereditary form of a cancer and in the sporadic form of the same cancer. Due to the existence of such hereditary chromosomal instability syndromes, inherited genetic instability may be of some importance in the evolution of sporadic colorectal cancers. METHODS: In vitro research on dermal fibroblasts is based on the theory, that all studied cells of an individual carry the same genetic material, irrespective of their in vivo expression. Increased in vitro tetraploidy (IVT+) in skin fibroblast cultures is supposed to be a germinally transmitted expression of genomic instability, with special reference to LS. At the same time the chromosomal aberrations, which occur in neoplasms, can be measured by flow cytometric DNA analysis. The DNA content, thus measured, is supposed to be an expression of somatic acquired genetic instability. Finally, since occult mandibular osteomas have been shown to be associated with FAP, we have investigated a substantial part of our patients with this phenotypical marker. AIM OF STUDY: In CRC the adenoma-carcinoma sequence is widely accepted, and the purpose of our investigation was to find a correlation, if any, between: Changes in adenoma flow cytometric DNA content and histological grade and type of adenomas. Changes in dermal fibroblast IVT+ from adenoma patients and histological grade and type of adenomas. Changes in dermal fibroblast IVT+ and flow cytometrical DNA content in adenomas and carcinomas from the same patients. Furthermore, we wanted to investigate if: The occurrence of IVT+ in skin fibroblasts among patients with CRC was different from that of IVT+ among patients without colorectal neoplasies. The occurrence of IVT+ in skin fibroblasts among patients with CRC was associated with the occurrence of occult mandibular osteomas in the same patients. The occurrence of dermal fibroblast IVT+ conveyed any prognostic significance in CRC patients. RESULTS AND CONCLUSIONS: 1) A significant correlation was found between both the occurrence of skin fibroblast IVT+ and adenoma DNA aneuploidy in relation to the degree of dysplasia and histological type of adenomas. This signifies, that inborn and acquired genetic instability is correlated to the adenoma-carcinoma sequence. IVT+ was found to be correlated to the progression of adenomas to carcinomas and not to the development of adenomas. 2) A direct correlation between IVT+ and adenoma DNA aneuploidy could not be demonstrated. However, among those patients with diploid adenomas and IVT+ 57% showed villous adenomas. Among those patients with diploid adenomas and IVT- only 14% had villous adenomas. This further substantiates the correlation of IVT+ to the adenoma-carcinoma sequence. IVT+ was highly associated with DNA aneuploidy in carcinomas, and since IVT+ was found to be significantly associated with CRC's with a DNA index > or = 1.5, it is suggested that IVT+ mainly is correlated to the early steps in tumor progression. 3) IVT+ was found in 34% of sporadic CRC, and tumor DNA aneuploidy was demonstrated in 73%...

Adenoma↗