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R Dick

Publications and source records attributed to R Dick.

At least 37 records · Page 2Linked to original sources
PubMed1995

Determination of ochratoxin A at the ppt level in human blood, serum, milk and some foodstuffs by high-performance liquid chromatography with enhanced fluorescence detection and immunoaffinity column cleanup: methodology and Swiss data.

An improved specific analytical method for ochratoxin A (OA) is presented, combining HPLC separation with enhanced fluorescence detection by post-column addition of ammonia. Commercial immunoaffinity columns (Biocode) were for the first time applied to the cleanup of extracts of body fluids; they could be used up to 20 times for blood serum. The extraction efficiency of OA from human serum and milk as well as its derivatization to esters were studied and improved. The quantitation limit for OA was improved and estimated at 5-10 pg/g for human milk and serum. The mean recovery of OA from serum and milk was estimated at 85%. The overall coefficient of variation for OA determinations in serum, milk and selected foodstuffs was estimated at 10% (concentration range 0.01-5 ng/g). The method was applied to sera of 368 blood donors, 10 pairs of maternal and fetal sera, as well as to 40 human milk samples and selected foodstuffs; the results are discussed.

Carcinogens↗
PubMed1995

Is proximal demarcation of ulcerative colitis determined by the territory of the inferior mesenteric artery?

The sharp demarcation between diseased and normal mucosa often observed in ulcerative colitis remains unexplained by current hypotheses of disease pathogenesis. To investigate whether this demarcation occurs at the watershed of vascular territories, the colonic arterial anatomy of 10 patients with ulcerative colitis was studied by in-vitro angiography and macroscopic and histological examination of total colectomy specimens. Of the 10 perfusion-fixed colectomy specimens studied, 7 had pancolitis associated with a complete marginal artery (Arteria marginalis coli) that spanned the entire length of the large bowel. 3 specimens had sharply demarcated disease in which the marginal artery arose from the inferior mesenteric artery and ended abruptly at the point of mucosal demarcation. The colon proximal to this point was histologically normal. These findings suggest that the proximal extent of colitis is determined by the limit of the marginal artery. We suggest that some characteristic of the mucosal microvasculature in the territory of the inferior mesenteric artery, possibly embryological in origin, predisposes the dependent colon to develop ulcerative colitis.

Adult↗
PubMed1995

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Humans↗
PubMed1995

The role of embolization in palliative care.

Transcatheter arterial embolization (TCAE) is a well recognized radiological technique that has been used for over 25 years. It is a method of diminishing blood flow through selected vessels by inserting haemostatic material under angiographic control. The procedure is performed under local anaesthetic through a femoral or, occasionally, an axillary approach. We present our experience of the use of TCAE in the management of pain and haemorrhage in three hospice inpatients in whom other options had been exhausted. The use of TCAE as a technique for the palliation of these symptoms in the hospice setting is discussed.

Adenocarcinoma, Follicular↗
PubMed1995

Cardiovascular effects of octreotide in patients with hepatic cirrhosis.

Octreotide is thought to reduce splanchnic and variceal blood flow with minimal effects on the systemic circulation in cirrhotic patients with portal hypertension. However, we noticed significant bradycardia in some patients immediately after administration of bolus doses of octreotide. Therefore, we investigated the effect of intravenous octreotide on systemic hemodynamics in 59 patients with cirrhosis. In two double-blind, placebo-controlled protocols, 32 patients received a 25-micrograms bolus and 20 patients received an infusion of 50-micrograms/hr of octreotide/placebo. Immediately after the bolus dose of octreotide was administered, there were significant reductions in pulse rate (77 +/- 3 vs. 65 +/- 3 beats per minute, P < .01) and cardiac output (9.2 +/- 0.8 vs. 7.9 +/- 0.8 L/min; P < .01) and significant increases in mean arterial pressure (81 +/- 3 vs. 87 +/- 3 mm Hg; P < .05), mean pulmonary artery pressure (9.1 +/- 1.0 vs. 16.6 +/- 1.5 mm Hg; P < .01), right atrial pressure (3.8 +/- 0.8 vs. 6.6 +/- 1.0 mm Hg; P < .01), right ventricular pressure (7.1 +/- 0.6 vs. 12.5 +/- 1.3 mm Hg; P < .01), pulmonary capillary wedge pressure (4.8 +/- 0.8 vs. 11.2 +/- 1.4 mm Hg; P < .01), systemic vascular resistance, and pulmonary vascular resistance. Thirty minutes after the start of the infusion, there were significant increases in mean right atrial pressure, right ventricular pressure, pulmonary artery pressure, and pulmonary capillary wedge pressure. This study suggests that intravenous octreotide has significant effects on the systemic circulation in patients with cirrhosis and that these effects appear to be more marked after administration of bolus doses.

Adult↗
PubMed1994

Incidence, risk factors, management, and outcome of portal vein abnormalities at orthotopic liver transplantation.

Portal vein thrombosis is often considered a contraindication to orthotopic liver transplantation. We have analyzed the incidence, risk factors, management and outcome of patients with portal vein thrombosis undergoing orthotopic liver transplantation. During the period from October 1988 to October 1992 140 grafts were performed on 132 patients. Fourteen had portal vein thrombosis with either partial (n = 7) or complete (n = 7) occlusion of the portal vein at surgery. Portal vein thrombosis was more common in patients with autoimmune chronic active hepatitis (3/5 vs. 11/127, chi 2 = 13.3, P < 0.001), cryptogenic cirrhosis (4/12 vs. 10/120, chi 2 = 7.2, P < 0.01), or those with tumors (6/22 vs. 10/110, chi 2 = 5.7, P < 0.05). In 13 of the 14 portal inflow was reestablished by flushing, balloon thrombectomy, or passage of a graduated dilator. In one patient complete fibrous obliteration necessitated a portal vein to right gastroepiploic vein anastomosis. On follow-up there have been 6 deaths in this group (6/14 = 43%) from recurrent cancer (n = 1), sepsis (n = 4), and cardiac and renal failure (n = 1). Four of these 6 patients had confirmation of PV patency on imaging. The remaining 8 patients are alive and well (median follow-up 37 months, range 6-53 months). Post-transplant portal vein thrombosis occurred in 3 of the 14 patients (21%) with a portal vein abnormality at surgery and in two of the 118 patients with a normal portal vein (3/14 vs. 2/118, chi 2 = 8.5, P < 0.01). Four of the 5 cases were successfully treated by surgical thrombectomy.

Adolescent↗
PubMed1994

Low-dose intra-arterial thrombolysis in the treatment of phlegmasia caerulea dolens.

Three patients with phlegmasia caerulea dolens treated successfully by low-dose intra-arterial thrombolysis are presented. In all patients a rapid improvement was observed and amputation avoided. The risk of pulmonary embolus was reduced by the use of a retrievable vena cava filter in one patient and thrombolytic therapy in the presence of a previously inserted cava filter in the other two.

Adult↗
PubMed1994

Emergency transjugular intrahepatic portasystemic stent shunting as salvage treatment for uncontrolled variceal bleeding.

Creation of a transjugular intrahepatic portasystemic stent shunt (TIPSS) was used as a rescue treatment for patients with variceal bleeding refractory to standard medical and endoscopic treatment. Over a 2-year period 242 episodes of variceal bleeding were treated and emergency shunting was performed on 20 patients with uncontrolled bleeding (Pugh grade A, one; B, seven; C, 12). The procedure was technically successful and controlled bleeding in all patients. Six patients had early rebleeding within 5 days, and further shunting was required in two. Two had late rebleeding related to shunt occlusion and had a further TIPSS procedure followed by portacaval shunting. Twelve patients died within 40 days from liver failure and sepsis, and there were two late deaths after 2 and 6 months, unrelated to bleeding. TIPSS insertion is an effective therapeutic option in patients with acute variceal bleeding refractory to medical and endoscopic treatment. However, despite control of bleeding in this group, the hospital mortality rate was high, reflecting the severity of the underlying liver disease.

Adult↗
PubMed1994

Review article: the transjugular intrahepatic portosystemic shunt (TIPS) in the treatment of portal hypertension.

The transjugular intrahepatic portosystemic shunt (TIPS) is a non-surgical intrahepatic shunt connecting the hepatic and portal veins. The shunt can be inserted successfully in more than 90% of patients and it effectively decompresses the portal venous circulation. Serious complications, such as intraperitoneal bleeding, occur but they are uncommon. The role of TIPS in the treatment of portal hypertension is currently being evaluated. There are few controlled data available to compare TIPS with established treatment such as drugs, injection sclerotherapy, endoscopic banding or shunt surgery. TIPS has also been used to treat ascites, the Budd-Chiari syndrome and cirrhotic hydrothorax. Concerns over the long-term patency and the true incidence of encephalopathy following TIPS raise doubts about its long-term efficacy. Controlled trials are required to demonstrate the cost-effectiveness of TIPS for individual indications before it is widely adopted. TIPS may find its most immediate application in the emergency treatment of active variceal haemorrhage refractory to standard medical and endoscopic therapy, as there is no satisfactory treatment currently available for this high-risk group. TIPS may also have a role in patients awaiting liver transplantation who bleed from varices. Long-term patency should not be an issue in this patient group and portal decompression may reduce blood transfusion requirements during transplant surgery.

Clinical Trials as Topic↗
PubMed1994

Rim calcification in primary liver cell carcinoma mimicking hydatid disease.

The case described is of a primary liver cell carcinoma (PLCC), which was initially misdiagnosed as hepatic hydatid disease. The computed tomographic appearances of hepatic hydatid disease are often characteristic although not specific. When supported by the clinical findings, however, they will probably not be confused with other liver masses. In this case the presence of peripheral rim calcification, commonly seen in hydatid disease but which has not been previously noted in PLCC, lead to an erroneous diagnosis.

Calcinosis↗
PubMed1994

Selective radionuclide localisation in primary liver tumours (pilot study).

The therapeutic potential of 131I-Lipiodol was investigated in 8 patients with cholangiocarcinoma (CCA) and 15 patients with hepatocellular carcinoma (HCC). Patients received one or two doses of 131I-Lipiodol via hepatic arterial injection. The mean total administered activity was 668 (SD 325) MBq in CCA and 953 (SD 477) MBq in HCC. One patient with CCA retained 131I-Lipiodol. The cumulative radiation dose was 9.6 Gy to tumour, 6.4 Gy to liver and 1.5 Gy to lung. The patient remained asymptomatic with no evidence of tumour 30 months from the start of treatment, whereas the remaining 7 patients exhibited tumour progression. The mean survival in CCA was 11.6 (SD 14.5) months. All 15 patients with HCC retained 131I with tumour: liver ratios of up to 30:1. The mean cumulative radiation dose was 34.7 (SD 32.4) Gy to tumour, 3.3 (SD 1.5) Gy to liver and 4.4 (SD 2.3) Gy to lung. The mean dose per administered activity was 3.8 (SD 4.1) cGy/MBq. Partial response (reduction in tumour size > 50%) was observed in 6 patients (40%). The mean survival was 7.1 (SD 6.0) months. 131I-Lipiodol can deliver highly selective internal irradiation to foci of HCC with evidence of objective response and may be the treatment of choice for patients with cirrhosis and a small tumour.

Adult↗
PubMed1994

The radiology of sarcoidosis.

Sarcoidosis is a multisystem granulomatous disease of unknown aetiology. The role of radiology is not only to support the clinical diagnosis but also as an adjunct to monitor the course and progression of the disease. The cornerstone of radiological assessment is the plain radiograph, however newer imaging methods are producing more information in relation to the anatomical distribution and pathophysiology which may ultimately have a profound effect on the management of this protean disease.

Female↗
PubMed1993

Peptide-induced changes in class I heavy chains alter allorecognition.

Class I molecules of the MHC are intimately involved in the development and function of CD8+ T cells. Small peptides, derived from endogenous proteins, bind within the Ag binding groove created by the beta-pleated sheets and alpha-helices of the alpha 1 and alpha 2 domains of the class I molecule. This peptide-MHC complex has been shown to influence allorecognition by CD8+ T cells. However, the precise role of peptide in alloantigen recognition remains unclear. We have previously shown that conformational changes induced in the class I molecules can be identified as specific alterations in serologic epitopes. These results suggested that alloreactive T cells may detect structural changes in MHC based on the nature of the peptide binding to the class I protein. Here, we have shown that, in at least some instances, alloreactivity may not depend on the recognition of a precise self-peptide but on an epitope on the class I molecule influenced by the peptide. The nature of specific peptides expressed by class I-bearing cells may, therefore, have a dramatic effect on T cell development, self-tolerance, and alloreactivity.

Amino Acid Sequence↗