Search PubMed⌕ Search

Biomedical subjects

R Dick

Publications and source records attributed to R Dick.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1989

Gianturco expandable metallic biliary stents: results of a European clinical trial.

Eleven patients with benign strictures (after choledochojejunostomy, n = 10; chronic pancreatitis, n = 1) and 16 with malignant biliary strictures (cancer of the pancreas, n = 7; cholangiocarcinoma, n = 5) were treated with a self-expanding metallic biliary stent. The patients with benign disease had failed treatment with surgical reconstruction and transhepatic balloon dilation. All patients had immediate relief of jaundice and cholangitis. In a follow-up period of 6-21 months, nine of the 11 patients with benign disease had no difficulties with infection, pruritus, or recurrent jaundice. In patients with malignant strictures, the stent produced relief of biliary obstruction unless recurrent tumor invaded the bile ducts. With careful patient selection, this stent appears to be useful in the management of biliary obstruction, particularly in benign disease.

Adult↗
PubMed1989

Wedged hepatic venous pressure recording and venography for the assessment of pre-cirrhotic and cirrhotic liver disease.

Wedged hepatic venous pressure recording and venography were investigated to assess histologic reflection of the stage of chronic liver disease. Forty-nine patients were studied. The four main groups and the means of the pressure gradients (WHVP - FHVP) with their 95% confidence limits were chronic active hepatitis (n = 12), 6 mm Hg (4.35-7.65); chronic hepatitis in transition to cirrhosis (n = 9), 10.3 mm Hg (6.6-14.1); and established cirrhosis (n = 8), 15.4 mm Hg (9.4-21.4); but only 3.4 mm Hg (2.2-4.6) in near-normal liver (n = 8). A pressure gradient of more than 5 mm Hg was always associated with significant liver disease on liver biopsy. In 25 patients venographies were assessed. Whereas patients with near-normal biopsy specimens had normal appearances, patients with more severe disease showed increasingly severe changes. The techniques applied should not replace liver biopsy. However, they provide relevant supplementary information, might have a place in follow-up studies to assess progression of disease, and occasionally reduce the need for liver biopsy.

Hepatic Veins↗
PubMed1989

Atherosclerotic renovascular disease causing renal impairment--a case for treatment.

Renovascular disease is a potentially curable cause of renal failure. In a prospective survey over an eighteen month period atherosclerotic renal artery disease was the cause of renal failure in 14% of patients over the age of fifty years accepted for renal replacement therapy at this hospital. Ten patients were found to be suffering from atherosclerotic renovascular disease causing renal failure but in only one was treatment able to reverse renal failure. The major problem with this group of patients is the widespread nature of their disease affecting many other organs. Significant morbidity is associated with their investigation. Although potentially curable, atherosclerotic renovascular disease is a frequent cause of renal failure in patients over the age of fifty years but is also difficult to treat.

Aged↗
PubMed1988

Evaluation of the dehydration-rehydration method for production of contrast-carrying liposomes.

We measured the amounts of three types of radiographic contrast media (RCM) that could be entrapped in liposomes prepared by the dehydration-rehydration vesicle (DRV) technique. To make DRVs, one initially makes water-containing, small unilamellar vesicles, adds contrast media and lyophilizes the mixture. Upon rehydration, the DRVs re-form, passively entrapping RCM. Diatrizoate, iohexol and iotrolan proved to be entrappable in similar amounts (diatrizoate was best), but all of these amounts were less than for other small molecules, such as carboxyfluorescein (P less than 0.05). Entrapment was directly proportional to lipid concentration (r = 0.76; P less than 0.002), and inversely related to iodine concentration (r = 0.86; P less than 0.002). Under ideal conditions with neutral lipids, 19.45 +/- 9.9% of diatrizoate was entrapped, corresponding to 1.05 +/- 0.50 g I per g lipid. These values are close to those achievable for large unilamellar vesicles. Use of an automated mixing device (the Microfluidizer) in place of sonication, facilitated production of large liposome batches and improved entrapment (P less than 0.05). Computed tomography (CT) scans of rats showed 30 and 218 HU of liver and spleen enhancement, respectively, per g I/kg injected DRVs. These studies showed this method (possible augmented by the Microfluidizer) allows efficient production of contrast-carrying liposomes.

Animals↗
PubMed1988

Non-invasive investigation of liver disease in haemophilic patients.

Liver biopsy specimens previously taken from 16 haemophilic patients with chronic non-A, non-B hepatitis were reviewed. The degree of fibrosis correlated with serum procollagen III peptide (sPIIIP) concentrations, measured both at the time of biopsy and 4.25 years later. Two patients with extremely high sPIIIP concentrations had collateral veins on computed tomography, suggesting portal hypertension. Twenty eight of 47 patients (60%) had splenomegaly on computed tomography, and of 28 patients in whom intravenous contrast medium was used, seven (25%) had collateral oesophageal veins. Serum procollagen III peptide estimations and computed tomography, both non-invasive investigations, indicated that hepatic fibrosis and portal hypertension had developed in a proportion of haemophilic patients with non-A, non-B hepatitis. Infection with the human immunodeficiency virus (HIV) may modify the course of this presumably cytopathic virus infection of the liver.

Adolescent↗
PubMed1988

Transthoracic image guided biopsy.

Transthoracic image guided biopsy is now firmly established in the armamentarium of diagnostic tests to establish the nature of a mass in the lung, pleura, mediastinum or chest wall. It may be performed under computed tomographic, ultrasonic or fluoroscopic control, and provided a fine needle technique is employed, morbidity is low. Worldwide reports show a 90% true positive yield and a false positive rate of less than 1%.

Aged↗
PubMed1987

The Carey-Coons percutaneous biliary endoprosthesis: a three-centre experience in 87 patients.

Eighty-seven patients with malignant obstruction of the biliary tract from three centres and deemed unsuitable for surgery underwent insertion of the 'Carey-Coons' transhepatic endoprosthesis. It was successfully introduced in all, with early relief of cholestasis in 97%. The 30 day mortality rate was 11.5%, which is lower than reported in series using different endoprostheses. Two fifths of patients had complications, especially cholangitis. Despite its ease of insertion the design of the endoprosthesis may be related to the high incidence of cholangitis and to formation of biliary sludge and occlusion found in follow up. Although the anchoring threads prevented migration, they may have played a role in infection at the skin entry site in four patients and in tumour seeding to the skin in a further two. Still further improvements in endoprosthesis design are desirable.

Adenoma, Bile Duct↗
PubMed1987

Molecular analysis of antigen recognition by insulin-specific T-cell hybridomas from B6 wild-type and bm12 mutant mice.

Molecular analysis of the heterodimeric T-cell antigen receptor of insulin-specific class II-restricted T-cell hybridomas (THys) derived from C57BL/6 (B6) wild-type and B6.C-H-2bm12 (bm12) mutant mice revealed that such T cells use a diverse V gene repertoire. Analysis of three THys that use related V genes, however, showed a number of novel features. Two THys that share major histocompatibility complex restriction use V alpha genes that are 98.6% homologous. Two THys sharing the same antigen fine specificity use a particular germ line V beta D beta J beta combination. A 21-base-pair deletion in the 5' segment of the J beta gene occurs in one THy, suggesting a novel mechanism for generating diversity in T-cell antigen receptor beta genes. The first amino acid encoded by N sequences at the V-D junction is conserved in a pair of T cells which recognize identical antigenic epitopes. The implications of these findings for the structural mechanisms underlying major histocompatibility complex-restricted antigen-specific T-cell recognition are discussed.

Animals↗
PubMed1987

Tetany despite normocalcaemia and normomagnesaemia following parathyroidectomy.

Two patients with long-standing hyperparathyroidism due to a parathyroid adenoma are described. Both had severe osteitis fibrosa cystica and a proximal myopathy. Both were treated with alfacalcidol (2 micrograms/day) prior to and following parathyroidectomy, and infused with calcium gluconate following the operation. Plasma total and ionized calcium and magnesium concentrations were maintained within the normal range. However, both developed tetany in the postoperative period in spite of normal ionized calcium and magnesium concentrations. Tetany continued for 4 weeks in one patient and for longer in the other. Prolonged hypercalcaemia may result in a state of neuromuscular excitability following parathyroidectomy even at high normal concentrations of ionized calcium.

Adenoma↗
PubMed1987

A controlled study of faecal distribution in ulcerative colitis and proctitis.

The object of this study was to assess faecal distribution and faecal stasis in patients with ulcerative colitis and healthy control subjects and to relate the findings to the activity and extent of the disease. Each subject ingested 10 radiopaque markers daily for 13 days and attended for a plain abdominal roentgenogram on the 14th day. Patients with active ulcerative proctocolitis retained significantly fewer markers in the whole colon (median values, 11 versus 24 markers) due to a decrease of markers in the left colon (median values, 3 versus 13 markers) compared with the control group (p less than 0.05). Patients with either proctitis or colitis in remission and control subjects retained similar numbers of markers. The results of this study suggest that, as a group, patients with proctocolitis do not have proximal faecal stasis.

Adult↗
PubMed1987

The treatment of Wilson's disease with zinc. IV. Efficacy monitoring using urine and plasma copper.

Progress has been made in establishing the efficacy and safety of oral zinc as a maintenance therapy for Wilson's disease. It is important to develop simple, noninvasive monitoring methods to assure the adequacy of zinc therapy in individual patients. In this paper we report the use of 24-hr urine copper and plasma copper measurements to monitor efficacy of zinc maintenance therapy in 30 Wilson's disease patients. In examples of therapeutic inadequacy such as noncompliance, these values increase. With continued long-term adequate therapy, they remain stable or decrease. These two simple monitoring tools appear to be very useful in monitoring Wilson's disease patients receiving zinc therapy.

Ceruloplasmin↗
PubMed1986

Cannon lecture. The impact of radiology on hepatology.

Because of remarkable advances in diagnostic imaging and the development of a variety of useful interventional techniques, radiology now plays a central role in the diagnosis and treatment of patients with hepatic disease. These include focal, vascular, and metabolic liver diseases, abnormalities of the biliary tract, and conditions associated with hepatic transplantation. Thus, optimal care of patients with liver disease now requires that there be close cooperation between the two specialties.

Angiography↗