Search PubMed⌕ Search

Biomedical subjects

R Dick

Publications and source records attributed to R Dick.

At least 91 records · Page 5Linked to original sources
PubMed1992

Octreotide inhibits the meal-induced increases in the portal venous pressure of cirrhotic patients with portal hypertension: a double-blind, placebo-controlled study.

The aim of this study was to determine the effects of the long-acting somatostatin analog, octreotide, on portal venous pressure and collateral blood flow in cirrhotic patients with portal hypertension during fasting and postprandial states. In a double-blind, placebo-controlled study, we investigated the effects of octreotide on the hepatic venous pressures and azygos blood flow of 21 patients before and after a standard liquid meal containing 40 gm of protein in 250 ml. Octreotide significantly reduced azygos blood flow from a mean of 499 +/- 65 ml/min to a mean of 355 +/- 47 ml/min (p < 0.01), but it had no effect on the hepatic venous pressure gradient. The hepatic venous pressure gradient of patients in the placebo group increased significantly, from a fasting mean of 16.4 +/- 1.6 mm Hg to a mean of 20.0 +/- 1.7 mm Hg 30 min after the meal (p < 0.01). In a second protocol hepatic venous pressures were measured in 20 patients at 30-min intervals for 2 hr after ingestion of the mixed meal. Again the placebo group showed a significant increase in the hepatic venous pressure gradient 30 min after the meal (20.4 +/- 1.5 mm Hg vs. 18.2 +/- 1.2 mm Hg; p < 0.05), but the group receiving octreotide showed no significant changes during the 2 hr of observation. We conclude that octreotide significantly reduces azygos blood flow, with little effect on portal venous pressure, and that it appears to inhibit postprandial increases in portal pressure in cirrhotic patients with portal hypertension.

Blood Flow Velocity↗
PubMed1991

Dietary intake and risk assessment of phototoxic furocoumarins in humans.

The question of whether the furocoumarin content of vegetables is sufficient to induce phototoxic skin reactions after ultraviolet irradiation was examined in two experiments with four human volunteers. In a first experiment, 300 g of celery roots (total phototoxic furocoumarin content 28.2 micrograms/g) was ingested. No skin reactions were observed after UVA exposure (1.5-9 J/cm2), and the blood levels of the furocoumarins--psoralen, 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP)--were below the analytical detection limit of 2 ng/ml. To investigate the phototoxic effects of a mixture of the two most important furocoumarins in vegetables, after gastro-intestinal uptake, 8-MOP and 5-MOP (15 mg each) were ingested separately in a 50% alcoholic solution. A strong and persistent erythema was induced in three out of the four subjects (UVA dose: 3-25 J/cm2). The blood levels immediately before UVA irradiation varied between 14 and 114 ng/ml (8-MOP), and 17 and 70 ng/ml (5-MOP). In the subject who did not show phototoxicity, the blood levels remained at trace levels (3 ng/ml). Two subjects were also tested with a mixture of 10 mg 8-MOP plus 10 mg 5-MOP; in one subject the mixture induced pigmentation only, while in the other a mild-to-medium erythema was induced. The blood levels of the furocoumarins in the two subjects were similar (12-15 ng/ml for 8-MOP and 5-MOP). It is concluded that in humans the phototoxic threshold dose of furocoumarin mixtures is of the order of 10 mg 8-MOP plus 10 mg 5-MOP, which is equivalent to about 15 mg 8-MOP per person (blood levels of 8-MOP and 5-MOP at 30 min after ingestion of about 10-15 ng/ml each). This phototoxic threshold dose was not reached by the consumption of celery roots and other conventional vegetables under normal dietary habits (experimental intake of 2-8 mg per subject of the potentially phototoxic furocoumarin mixture). However, the safety factor between the possible actual intake of furocoumarins and the phototoxic threshold dose is about 2-10, which is relatively small.

5-Methoxypsoralen↗
PubMed1991

Selective regional chemotherapy of unresectable hepatic tumours using lipiodol.

Over a 30 month period from 1987 to 1990, selective hepatic cannulation under fluoroscopic control was performed in 57 consecutive patients with primary and secondary malignancies of the liver. Fifty-three patients were subsequently treated using intra-arterial Lipiodol emulsified with epirubicin. The tumours treated were hepatocellular carcinoma (n = 35), metastatic adenocarcinoma (n = 14), intrahepatic cholangiocarcinoma (n = 3) and leiomyosarcoma (n = 1). For hepatocellular carcinoma the cumulative survival was 38% at one year; the median survival was 12.2 months for Stage I, 6.3 months for Stage II and 0.9 months for Stage III tumours. In metastatic disease the cumulative survival was 63% at one year. These data suggest that targeted intra-arterial chemotherapy with Lipiodol-epirubicin is a useful palliative therapy for patients with Stage I and II HCC, and that a controlled trial of this treatment should be undertaken.

Adenocarcinoma↗
PubMed1991

[Femoral anteversion in upper femoral epiphysiolysis in adolescents. Apropos of 25 cases].

CT-scan examinations have been performed in 25 children with slipped capital femoral epiphysis (SCFE) and in 127 children in an out-patients orthopaedic consultation. A low femoral anteversion (FA) was present in SCFE. This morphological abnormality, in association with other factors, could explain the production of SCFE at the moment of the most important fragility of the upper femoral growth plate, which is puberty. A statistical analysis showed that the risk of SCFE was distinctly greater, even for the contralateral hip when FA was low.

Adolescent↗
PubMed1990

Use of Gianturco self-expandable stents in the tracheobronchial tree.

Gianturco self-expandable stents were used successfully in the management of 5 patients with tracheobronchial pathology. Placement was performed under endoscopic and fluoroscopic guidance. None of the patients has experienced complications secondary to the stent placement, and in all of them the clinical problems resolved satisfactorily. Longer follow-up is required to determine the place of tracheobronchial stenting in patients with respiratory compromise.

Aged↗
PubMed1990

The effect of non-protein liquid meals on the hepatic venous pressure gradient in patients with cirrhosis.

It has been suggested that protein feeding increases portal pressure in cirrhotic patients, but that carbohydrate and fat have little effect. We examined the relationship between feeding and portal pressure, using different liquid test meals (250 or 500 ml non-protein, 250 ml protein-containing, 500 ml water), in 29 alcoholic patients with cirrhosis and portal hypertension. The mean hepatic venous pressure gradient (HVPG) increased significantly 30 min after the protein meal (10% increase; p = 0.009) and returned to basal levels at 60 min. The mean HVPG also increased significantly after the non-protein meal: after 500 ml the increase was 23% at 30 min (p = 0.046) and 17% at 60 min (p = 0.12); and after 250 ml it was 15% at 30 min (p = 0.012) and 7% at 60 min (p = 0.05). Ingestion of 500 ml water caused a small, non-significant, increase in mean HVPG. Plasma glucagon levels increased significantly at 30 and 60 min after the protein meal, but did not change significantly after the non-protein meal or water. Both protein-containing and non-protein meals significantly elevate HVPG in alcoholic patients with cirrhosis and portal hypertension.

Adult↗
PubMed1990

Self-expandable stainless steel braided endoprosthesis for biliary strictures.

A new type of biliary stent was inserted in 45 patients with symptomatic biliary strictures, 40 malignant and five benign. The stent is made of stainless steel woven into a tubular mesh. It is introduced in compressed form on a 7- or 9-F delivery catheter and released at the site of the stricture. Fully open, the stent has an internal diameter of 1 cm. The 30-day mortality was 7%. The early (less than 72 hours) complication rate was 16%. Recurrent jaundice occurred in 42%; late complications of sepsis without jaundice occurred in an additional 11%. None of the stents migrated. This new design allows a large-diameter stent to be inserted percutaneously without increased risk of complications. The frequency of recurrent jaundice, however, was not less than that observed with plastic stents, but this may have reflected the spectrum of patients treated, many with hilar strictures and previous interventions.

Aged↗
PubMed1989

Influence of some instrumental parameters on the determination of quantitative data using the PET scanner PC4096-15WB.

In order to evaluate the influence of physical and instrumental limitations of the PET technique on metabolic data, various parameters have been tested. The measurements were done with a whole body PET scanner PC4096-15WB. The dependence on the transaxial resolution of reconstruction filter cut off frequency alpha c was investigated. The high resolution (4.8 mm at r = 0 in the field of view) and the low scatter fraction (less than 5%) of this system yields a higher grey/white matter ratio (3.8:1) than that found with older scanners (2:1). The use of a rotating pin source allows transmission scans to be performed after tracer administration with an error of less than 5%.

Image Processing, Computer-Assisted↗