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Biomedical subjects

A Hilson

Publications and source records attributed to A Hilson.

At least 19 recordsLinked to original sources
PubMed1999

In vitro assessment of Lipiodol-targeted radiotherapy for liver and colorectal cancer cell lines.

Intra-arterial Lipiodol has been used to deliver targeted therapies to primary, and some metastatic, liver cancers. Targeted radiotherapy has been used by substituting the iodine in Lipiodol with 131Iodine (131I). Early clinical results are encouraging, but the variable response may partly depend on local pharmacokinetics. This study evaluated the in vitro cytotoxic effects of 131I-Lipiodol on human hepatocellular carcinoma (Hep-G2), human colorectal metastatic cancer (SW620), human colorectal hepatic cancer (LoVo) and human umbilical vein endothelial cells (HUVEC) cell lines. The cell cultures were exposed to 131I-Lipiodol for 48 h, following which cell counts and viability were assessed by haemocytometer, S-Rhodamine uptake and radioactivity assay. The effect of exposure to control Lipiodol, 131I-Lipiodol and 131I alone was evaluated. 131I-Lipiodol was cytotoxic against all the cancer cell lines but not against the non-malignant (HUVEC) cell line. The cytotoxicity effects were very similar in all the cancer cell lines. There were no cytotoxic effects following exposure to plain 131I in any of the cell lines (malignant and non-malignant). A similar trend was seen with radioactivity counts using a gamma counter. The cytotoxic effect of 131I-Lipiodol had a graded effect with an increase in cytotoxicity following the increase in the radioactive dose. This study showed that there was a marked cytotoxic effect by 131I-Lipiodol on all the cancer cell lines. There was no difference between the controls and the 131Iodine. This suggests that effective 131I-Lipiodol targeted therapy is dependent on the uptake and retention of Lipiodol by malignant cells.

Cell Division↗
PubMed1997

Prospective study of hepatobiliary scintigraphy and endoscopic cholangiography for the detection of early biliary complications after orthotopic liver transplantation.

BACKGROUND: Biliary complications are a significant cause of morbidity and death after orthotopic liver transplantation (OLT). This study was a prospective evaluation of endoscopic retrograde cholangiography (ERC) and hepatobiliary scintigraphy (HBS), using 99mTc Mebrofenin, to detect early biliary complications following OLT. METHODS: One hundred consecutive patients who had OLT with a biliary duct-to-duct anastomosis were studied. Of these, 67 had both ERC and HBS performed within 30 days of OLT. Sensitivity, specificity and diagnostic accuracy of HBS in identifying biliary leak or stricture was calculated. RESULTS: Of the 67 cholangiographies performed 45 were normal. In 22 patients there was radiological evidence of a leak (n = 14) or stricture (n = 8) which required further intervention in nine and four patients respectively. The sensitivity and specificity of scintigraphy for the detection of biliary leak after transplantation was 50 and 79 per cent and for biliary stricture 62 and 64 per cent respectively. No patient with normal scintigraphy required biliary intervention. Only six of 14 patients with biliary leaks and two of 20 with strictures suggested by scintigraphy required intervention. If both ERC and HBS reported leak or stricture, the intervention rate was considerably higher at five of seven leaks and two of five strictures. CONCLUSION: This study suggests that scintigraphy is a useful screening test for biliary complications after OLT, ERC is only necessary if HBS is abnormal.

Adolescent↗
PubMed1996

Inter-observer agreement in the reporting of 99Tcm-DMSA renal studies.

The early identification of renal cortical scarring secondary to urinary reflux and/or renal infection is important in the management of patients with recurrent disease. Scintigraphic imaging of the renal cortex using 99Tcm-dimercaptosuccinic acid (DMSA) is often considered the standard method for the diagnosis of renal scars in both adults and children. Consistent reporting of 99Tcm-DMSA is nevertheless essential in ensuring that the clinician can act on the data reported. In this study, seven experienced observers were asked to report, independently, 99Tcm-DMSA data sets from 32 patients. The observers were asked to note the presence of a space occupying lesion or of a renal cortical scar(s) and to conclude if the kidney was normal or abnormal. There was marked variation in the number of renal cortical scars reported, the total number of scars seen and whether or not the kidney was normal or abnormal. After peer review of all data, consensus and referenced criteria were arrived at for a reanalysis of data. All scans were reread by the observers. There was some improvement in the concordant reporting of kidneys with renal scars (51 vs 61%) and whether or not the kidney was normal or abnormal (53 vs 63%). However, this was not statistically significant (at a level of P < 0.05). This study demonstrated significant inter-observer variation regarding the reporting of 99Tcm-DMSA studies. A consensus with agreed guidelines for data interpretation did not significantly affect this apparent lack of consistency of reporting.

Adolescent↗
PubMed1996

Detection of early asymptomatic esophageal dysfunction in systemic sclerosis using a new scintigraphic grading method.

OBJECTIVE: To screen patients with systemic sclerosis (SSc) for esophageal disease and to demonstrate a new system of grading dysmotility; to determine the relationship between the symptom of dysphagia and the degree of hypomotility shown by scintigraphy. METHODS: 301 patients with SSc were studied by esophageal scintigraphy using a semisolid orally ingested bolus to detect esophageal dysfunction and gastroesophageal reflux. A new system of grading was used to quantitate the degree of dysfunction, ranging from grade 0 (normal) to grade 4 (severe abnormality). RESULTS: 246 (82%) patients in the study population had evidence of esophageal hypomotility. Gastroesophageal reflux was noted in 83 (28%) patient. The largest number of patients (33%) were found to have grade 2 abnormalities. The number of patients with reflux decreased with increasing severity of grade, from grade 2 to grade 4 (35 to 13%). A retrospective study of the symptoms of 50 of the total study population showed that increasing severity of grade correlated with increasing mean duration of SSc. There was no significant relationship between disease subset and the presence or severity of esophageal hypomotility. 60% of patients in grades 1 and 2 (i.e. with observed dysmotility shown on scintigraphy) had no symptoms of dysphagia. In the more severe grades (scan grades 3 and 4), symptoms of dysphagia correlated with increase in grade. CONCLUSION: Symptoms may be unreliable in judging the presence of extent of esophageal disease in SSc. Esophageal scintigraphy is a useful noninvasive screening test for the detection of asymptomatic disease. The new grading system provides information that rapidly identifies the stage of esophageal disease and gives comparative data for followup and interventional studies.

Adolescent↗
PubMed1993

Deletion analysis maps ocular albinism proximal to the steroid sulphatase locus.

We describe a pedigree in which four male members are affected by a contiguous gene abnormality involving the short arm of the X chromosome (Xp22.32). Bivariate flow cytometry of lymphoblastoid cell lines from two of these individuals and a normal male showed a 6-7 megabase deletion in affected males, and high resolution chromosomal G-banding of an obligate heterozygote showed the deletion to reside in the Xp22.32 region. Affected members had X-linked ichthyosis due to steroid sulphatase deficiency, Kallmann's syndrome, but no ocular albinism. In two out of four affected individuals studied, there was unilateral renal agenesis. Deletion analysis using the Xp22.32 markers MIC2, DXS31, DXS 89, GMGX9, DXS278, DXS143, and DXS9 showed that the deletion extended from DXS31 to DXS143 (inclusive). The absence of ocular albinism in this pedigree shows conclusively that the X-linked ocular albinism gene resides proximal to the DXS143 locus. Further, the inconstant association of unilateral renal agenesis with X-linked Kallmann's syndrome, even when the latter is caused by a complete deletion of the gene, suggests that the absence of the X-linked Kallmann gene can be compensated in renal development.

Albinism, Ocular↗
PubMed1991

Therapeutic aspects of radio-isotopes in hepatobiliary malignancy.

Liver tumours frequently present at a late stage and only a minority of patients are likely to benefit from resection or transplantation. Inoperable tumours carry a grave prognosis. External beam irradiation of the liver is dose-limited by the radiosensitivity of hepatocytes, particularly in the presence of cirrhosis, but internal radiation using radio-isotope sources can achieve more selective irradiation of the chosen field. Sealed sources are dose-limited by their effects on surrounding tissues, whereas with unsealed sources the dose of radio-isotope administered is limited by bone marrow suppression. Iridium-192 wires are most frequently employed as a sealed intracavitary source. They may be inserted surgically, transhepatically or endoscopically. Doses of up to 60 Gy can be delivered to a malignant biliary stricture without damage to the surrounding parenchyma. The incidence of cholangitis is low if treatment is administered after insertion of an endoprosthesis. Unsealed radio-isotope sources may be injected directly into the tumour, administered embolically via the hepatic artery in the form of microspheres or lipid droplets, or given via parenteral infusion attached to tumour-specific antibodies. Of these vehicles, the lipid agent Lipiodol appears to be the most effective and can deliver a potentially lethal dose of radiation to small tumours. Host reaction to the injected antibody remains a major drawback to the use of monoclonal antibodies as targeting agents. Iodine-131 is a beta- and gamma-emitter, producing a local tumoricidal effect and allowing accurate dosimetry by means of external scintigraphy. Yttrium-90 is a pure beta-emitter with a greater maximum beta energy and cytotoxic range; however, it is retained in bony tissues, resulting in a dose-related risk of marrow suppression. Bone absorption cannot be measured by external imaging owing to the absence of gamma emission. This lack of accurate dosimetry, coupled with the toxic side-effects of yttrium treatment, make iodine-131 the current isotope of choice.

Antibodies↗
PubMed1991

Ablation of recurrent primary liver cancer using 131I-lipiodol.

A case of recurrent hepatocellular carcinoma following resection is reported. The patient received 2 treatments of 131I-lipiodol administered via the hepatic artery at angiography. Good localization in tumour tissue was observed on subsequent computed tomographic scans and no adverse effects were seen after either treatment. After the first treatment 2 nodules of recurrent tumour were resected and proved to be totally necrotic. The patient remains well 9 months later with a persistently elevated serum alphafetoprotein but no evidence of residual tumour. It is suggested that 131I-lipiodol may be the treatment of choice for small tumours in elderly high-risk patients.

Aged↗
PubMed1989

Gallium-67 scintigraphy in the detection of infected polycystic kidneys in renal transplant recipients.

Renal transplant recipients with underlying polycystic kidney disease (PKD) may present with recurrent urinary tract infection (UTI). This is often due to persistent infection in one or both of the native polycystic kidneys. It may be necessary to remove the infected kidney in order to remove the source of persistent infection. Gallium-67 scintigraphy was performed in 11 renal transplant recipients with underlying PKD. Positive studies were obtained in four recipients who had recurrent UTI. The scan also localized which of the kidneys (native or transplant) was the site of persistent infection. These four recipients subsequently had nephrectomy of the infected polycystic kidneys as suggested by the scan. Negative scans were obtained in seven recipients who did not have recurrent UTI. Gallium scintigraphy is a useful test for detecting and localizing the site of persistent UTI in renal transplant recipients with underlying PKD who present with recurrent UTI.

False Negative Reactions↗