Biomedical subjects

W Prevoo

Publications and source records attributed to W Prevoo.

8 recordsLinked to original sources

PubMed2005

Adverse effects of radiofrequency ablation of liver tumours in the Netherlands.

BACKGROUND: Radiofrequency ablation (RFA) is a new treatment for liver tumours. Complications encountered after RFA in the Netherlands were evaluated in the present study. METHODS: Between June 1999 and November 2003 patients undergoing RFA of irresectable liver tumours in eight medical centres were registered prospectively. RESULTS: One hundred and forty-three RFA procedures were performed in 122 patients. RFA was combined with partial hepatectomy in 37 instances. Death occurred after two procedures (1.4 per cent), and was mainly due to concomitant partial hepatectomy. A total of 19 major complications occurred after ten procedures, including biliary tract damage (seven patients), liver failure (four), hepatic abscess (three), peritoneal infection (two), intrahepatic haematoma (one), hepatic artery aneurysm (one) and pulmonary embolism (one). Twenty-four minor complications were related to concomitant partial hepatectomy or laparotomy. The overall complication rate was 20.3 per cent and the rate of complications related directly to RFA was 9.8 per cent. CONCLUSION: The procedure-specific complication rate was almost 10 per cent and it is recommended that RFA should be performed only by an experienced team comprising a hepatobiliary surgeon, gastroenterologist, hepatologist and interventional radiologist. Biliary stricture, hepatic vascular damage and hepatic abscesses were the most common major complications.

Adult↗

PubMed2004

The significance of circumscribed malignant mammographic masses in the surveillance of BRCA 1/2 gene mutation carriers.

Breast cancers in gene mutation carriers may escape mammographic detection because of rapid growth and tumor expansion. Therefore, they may mimic benign lesions on the mammogram. Twenty-nine BRCA 1/2 mutation carriers under surveillance developed 31 breast cancers between 1994 and 2001 at a mean age of 44.2 years. Controls were 63 women with 67 breast cancers in the same period at a mean age of 53.8 years, also under surveillance because of a life time risk of at least 15%. In 26% of the carriers vs. 48% of the controls, mammography was the method that first suspected a malignancy. Seven radiologists performed a retrospective review of the original mammograms to establish technical assessment, with special attention for circumscribed lesions and estimated probability of malignancy. In the mutation carriers seven (23%) circumscribed non-calcified mammographic masses were found and three in the controls (4.5%) P=0.01. These masses were proven to be malignant. In both groups around 70% of these fast-growing circumscribed lesions were detected by the patients. The masses were situated in breasts with a good interpretable breast pattern. BRCA 1/2 mutation carriers had a significantly higher percentage of circumscribed non-calcified mammographic masses that proved to be malignant. These mammographic lesions in women at high risk should be described as at least Birads 0 and worked-up with ultrasound and needle biopsy.

Adult↗

PubMed2004

Effect of homocysteine-lowering treatment with folic acid plus vitamin B on cerebrovascular atherosclerosis and white matter abnormalities as determined by MRA and MRI: a placebo-controlled, randomized trial.

BACKGROUND: A high plasma homocysteine concentration is an independent risk factor for large and possibly small vessel disease. We investigated the effects of homocysteine-lowering treatment with folic acid plus vitamin B(6) on markers of cerebrovascular atherosclerosis and cerebral microangiopathy. MATERIALS AND METHODS: Using 158 healthy siblings (mean age 46.0 +/- 7.6 years) of patients with premature atherosclerotic disease, we performed a randomized, placebo-controlled trial using 5 mg of folic acid plus 250 mg of vitamin B(6) daily (n = 78) or placebo medication (n = 80). Participants were followed for 2 years with magnetic resonance angiography (MRA) (carotid stenosis; carotid and/or vertebral elongation) and magnetic resonance imaging (MRI) (white matter abnormalities; cerebral atrophy). RESULTS: Seventeen (10.8%) subjects refused MRA/MRI owing to claustrophobia and were excluded. From the remaining 141 participants, 68 received vitamin and 73 received placebo medication [42 (61.8%) and 48 (65.8%) had postmethionine hyperhomocysteinaemia, respectively]. Twenty-four participants (15.2%; 10 in the treatment and 14 in the placebo group) did not complete both years of the trial. Vitamin treatment was associated with an increase in plasma folate (13-fold vs. placebo; P < 0.001) and vitamin B(6) (8.8-fold; P < 0.001). Fasting and postmethionine total homocysteine concentrations decreased 38.7% (95% CI, 27.4-50.0) and 29.1% (95% CI, 19.2-39.0) vs. placebo (all P < 0.001). During follow up six individuals in the vitamin-treated and 11 in the placebo-treated group deteriorated in their outcome measurements. Vitamin treatment, as compared with placebo, was associated with nonsignificantly improved outcomes on both MRA and MRI outcome measurements (odds ratio 0.48; 95% CI 0.17-1.41; P = 0.18 and 0.48; CI 0.14-1.60; P = 0.23, respectively). CONCLUSIONS: These results could indicate a possible favourable effect of homocysteine-lowering treatment on cerebrovascular atherosclerosis and cerebral microangiopathy among healthy siblings of patients with premature atherosclerotic disease, but larger trials are required to establish this with certainty.

Adult↗

PubMed2003

Initial experience with radiofrequency ablation for hepatic tumours in the Netherlands.

AIMS: The aim of this study is to report initial experience with radiofrequency thermoablation (RFA) of malignant hepatic tumours. METHODS: From June 1999 to November 2001, a seven centre study of 50 patients who had undergone RFA, included 102 primary or metastatic tumours. Multimodality therapy, complications, disease free survival and location of recurrence were recorded. Histopathologic examination was performed in a number of tumours treated with RFA and subsequently resected to determine the effect of RFA on the tissue level. RESULTS: 11 tumours (seven patients) were resected after prior treatment with RFA; NADH-diaphorase staining in all these tumours demonstrated non-viable tumour. Postoperative morbidity and mortality occurred in 14 patients and one patient, respectively, in three cases related to the RFA procedure. Median follow-up of 41 patients with non-resected RF ablated tumours was 11 months (range 1-24 months). 26 patients developed a recurrence of which three at the RFA site after 6-12 months. CONCLUSIONS: RFA provides a simple method for local treatment of liver tumours. The introduction of this technique nevertheless involves morbidity and mortality.

Adult↗

PubMed2001

Technical considerations in laparoscopic liver surgery.

BACKGROUND: Laparoscopic solid organ surgery has gained growing acceptance, but this does not hold for laparoscopic surgery of the liver. Laparoscopic liver surgery mainly comprizes diagnostic procedures and treatment of liver cysts. However, we believe there is room for a laparoscopic approach to the liver in selected cases, with the benefits that may be expected from laparoscopic solid organ surgery. METHODS: Between 1993 and 2000, 10 patients with various lesions of the liver underwent laparoscopic surgery. Indications consisted of cystic disease (n = 2), hemangioma (n = 2), focal nodular hyperplasia (n = 2), liver abcess (n = 1), and liver metastasis (n = 3). Laparoscopic treatment varied from fenestration (n = 3) to wedge resections (n = 5), and formal left lateral hepatectomy (n = 2). RESULTS: The mean patient age was 54 years (range, 34-71 years). The mean operative time, including laparoscopic ultrasonography, measured 180 min (range, 80-240 min). Peroperative blood loss ranged from 200 to 450 ml. There was no mortality. In two patients, conversion to laparotomy was necessary. There were no postoperative complications. The mean hospital stay was 6 days (range, 4-11 days). CONCLUSION: Laparoscopic treatment should be considered in selected patients with benign and malignant lesions in the left lobe or frontal segments of the liver.

Adult↗

PubMed1993

Macrophage populations in different stages of induced hepatic metastases in rats: an immunohistochemical analysis.

Macrophages play a role in the host defence against cancer. Little is known about changes in macrophage populations during early metastatic growth. To evaluate the distribution, number and phenotype of macrophages in the development of hepatic metastases in a rat model (Wag/Rij rats and syngeneic CC531 colon carcinoma cell line), an immunohistochemical study was performed with the monoclonal antibodies ED1 (monocytes, and all macrophages), ED2 (resident tissue macrophages, like Kupffer cells) and ED3 (a subpopulation of macrophages which may play a role in the recruitment of lymphocytes). OX19 and His14 were used to identify lymphocytes. In this study a new monoclonal antibody CC52 is described, which recognizes the CC531 tumour cell line. Liver metastases were induced by injection of CC531 colon carcinoma cells into a mesenteric vein. Rats were killed at various intervals. Results show three major macrophage populations during hepatic tumour growth: (1) on day 3, infiltrates are observed around the micrometastases, which contain mainly newly recruited macrophages (ED1+ and ED2-); (2) after 7 days, ED3-positive (ED3+) macrophages together with T lymphocytes are found in the infiltrates; (3) an increase in the number of ED2-positive (ED2+) Kupffer cells is observed in the liver parenchyma after 14 days. In conclusion, the present results suggest that various populations of macrophages, newly recruited (ED1+) as well as resident Kupffer cells (ED2+), are involved in the immune response against tumour cell deposits in the liver.

Adenocarcinoma↗

PubMed1992

The impact of intraoperative ultrasonography of the liver on the surgical strategy of patients with gastrointestinal malignancies and hepatic metastases.

Intraoperative ultrasonography (IOUS) of the liver is a very useful tool during surgery for gastrointestinal tumors or hepatic tumors. In a prospective study of 82 elective operations for 57 gastrointestinal tumors and 25 hepatic tumors or metastases, we compared IOUS with preoperative ultrasonography, CT-scanning and MRI. IOUS supplied additional information in 38% of the operations. In 22% of the cases, this had a major impact on the intraoperative strategy with an alteration of the procedure. IOUS has a higher detection rate of intrahepatic lesions, discriminates better between solid or cystic nature of the tumor and offers the possibility of performing a safe and radical hepatic resection by its ability to localize lesions in relation to vascular structures. IOUS is a safe and simple technique which will be more cost-effective than extensive preoperative evaluation of the liver. It provides a more complete clinical staging of patients for whom adjuvant therapy is considered after resection of a colorectal carcinoma.

Adult↗

PubMed1991

Intra-operative ultrasonography of the liver: a prerequisite for surgery of colorectal cancer?

The results and consequences of intra-operative ultrasonography of the liver were studied in 50 patients who had laparotomy for colorectal cancer. Compared with preoperative imaging techniques like US, CT and MRI, intra-operative US had a higher sensitivity for intrahepatic lesions. Especially in case that adjuvant therapy could have been considered, intra-operative US gave relevant information in 10 patients (20%) by altering the stage of the primary tumour. Four of the 50 patients showed more liver metastases at intra-operative US than detected by preoperative imaging techniques. Resectional therapy of liver metastases could be prevented in these four patients. We advise intra-operative US as routine for all patients undergoing laparotomy for colorectal cancer especially if adjuvant chemotherapy is considered. When surgery is scheduled extensive preoperative liver examination can be avoided if intra-operative US is available.

Adult↗