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Biomedical subjects

T E Hilditch

Publications and source records attributed to T E Hilditch.

At least 19 recordsLinked to original sources
PubMed1998

Comparison of helisal rapid blood test and 14C-urea breath test in determining Helicobacter pylori status and predicting ulcer disease in dyspeptic patients.

OBJECTIVE: Noninvasive tests for Helicobacter pylori are used increasingly. Our aim was to compare the Helisal Rapid Blood (HRB) test and 14C-urea breath test (UBT) for determining H. pylori status and predicting ulcer disease. METHODS: Three hundred fifty-one consecutive patients with dyspepsia (mean age 40 yr; range 16-77 yr) had an HRB test and UBT followed by endoscopy with biopsies of the antrum and body for histology and antral urease slide test (CLO test). Patients were excluded if they had previously confirmed ulcer disease, gastric surgery, or anti-H. pylori therapy or were taking nonsteroidal anti-inflammatory drugs. RESULTS: Sixty-three percent of the patients were "gold standard" H. pylori positive (positive CLO test, positive staining), 34% were gold standard negative (negative CLO test, negative staining), and 3% had conflicting CLO test and histology. The UBT was superior to HRB for determining H. pylori status (sensitivity 98% vs 92%, p = 0.04; specificity 100% vs 69%, p < 0.001). The specificity of the HRB decreased with increasing patient age (74% for age <46 yr; 57% for age > or =46 yr). A negative UBT was superior to a negative HRB test for predicting the absence of ulcer disease (47% vs 36 %; p < 0.01). A positive UBT was similar to a positive HRB in predicting the presence of ulcer disease (92% vs 84%; p = 0.23). CONCLUSIONS: The HRB test is inferior to the UBT for determining H. pylori status. The tests have a similar ability to predict the presence of ulcer disease when positive, but a negative UBT is a better predictor of the absence of ulcer disease.

Adolescent↗
PubMed1997

The Helicobacter pylori breath test: a surrogate marker for peptic ulcer disease in dyspeptic patients.

BACKGROUND: There is interest in noninvasive H pylori testing as a means of predicting diagnosis and determining management in dyspeptic patients. AIMS: To assess the value of the 14C urea breath test as a predictor of peptic ulcer disease in patients presenting with dyspepsia. PATIENTS AND METHODS: 327 consecutive patients referred for investigation of dyspepsia had a 14C urea breath test performed before endoscopy. Patients were not included if they had previously confirmed ulcer disease, previous gastric surgery, or were taking non-steroidal anti-inflammatory drugs. RESULTS: Of the 182 patients with a positive 14C urea breath test, duodenal and/or gastric ulcers were present in 45% and erosive duodenitis in a further 2%. Oesophagitis was present in 12% of the breath test positive patients with two thirds of the oesophagitis patients having co-existent ulcer disease. The prevalence of ulcer disease in the H pylori positive dyspeptic patients was independently related to smoking and previous investigation status. If previously uninvestigated, the prevalence of ulcers was 67% in smokers and 46% in non-smokers. If previous upper gastrointestinal investigations were negative, the prevalence of ulcers was 53% in smokers and 28% in non-smokers. Of the 136 patients with a negative breath test, only 5% had peptic ulcers. The most frequent endoscopic finding in these H pylori negative subjects was oesophagitis, being present in 17%. CONCLUSIONS: This study demonstrates that a positive H pylori test is a powerful predictor of the presence of underlying ulcer disease in dyspeptic patients, especially if smokers, and that a negative H pylori test is a powerful predictor of the absence of ulcer disease. It also indicates that a negative upper gastrointestinal investigation does not preclude subsequent presentation with ulcer disease.

Adolescent↗
PubMed1996

The radiation dose to the urinary bladder in radio-iodine therapy.

A new MIRD dynamic model has been used to provide estimates of the dose to the urinary bladder resulting from the administration of the therapeutic agents 131I as iodide (for thyroid carcinoma) and 131I meta-iodobenzylguanidine (MIBG) (for neuroendocrine tumours). Because the latter agent is used for therapeutic purposes in children, dose estimates were obtained for subjects aged 1 year and upwards. Those parameters likely to influence the bladder dose were also investigated, making use of the inherent flexibility of the model. For an administration of 1 GBq of either 131I as iodide or 131I MIBG to an adult subject, the radiation dose to the inner surface of the bladder was estimated to be approximately 1100 mGy, which is nearly twice the value estimated using a constant-volume bladder model. The new model produced dose estimates for children (within the range 1000-2750 mGy GBq-1 of 131I MIBG) which were approximately 50% greater than those derived using a constant-volume bladder model. The urine flow rate was found to have the greatest effect on the bladder dose, a flow of twice the normal rate resulting in a reduction in the bladder dose by a factor of two. On the other hand, a reduction in the urine flow rate to half the normal value was estimated to increase the radiation dose by a factor of two. This was true for subjects of all ages. With normal voiding, the average dose to the bladder wall from 131I beta-radiation was estimated to be 5-13% of the surface beta dose for subjects of different ages, the values being greater in children. This has to be compared with a photon contribution to the average bladder wall dose amounting to 10-20% of the combined surface dose both from beta-particles and from photons.

3-Iodobenzylguanidine↗
PubMed1995

Multi-modality megatherapy with [131I]meta-iodobenzylguanidine, high dose melphalan and total body irradiation with bone marrow rescue: feasibility study of a new strategy for advanced neuroblastoma.

New therapeutic approaches are needed for advanced neuroblastoma as few patients are currently curable. We describe an innovative strategy combining [131I]meta-iodobenzylguanidine ([131I]mIBG) therapy with high dose chemotherapy and total body irradiation. The aim of combining these treatments is to overcome the specific limitations of each when used alone to maximise killing of neuroblastoma cells. Five children received combined therapy with [131I]mIBG followed by high dose melphalan and fractionated total body irradiation. Autologous bone marrow transplantation was undertaken in 3 patients and allogeneic in 2 patients. One patient received additional localised radiotherapy to residual bulk disease. One patient is alive without relapse 32 months after treatment. 4 patients relapsed after remissions of 9, 10, 14 and 21 months. These results indicate that this combined modality approach is feasible and safe, but further evaluation is necessary to establish whether it has advantages over conventional megatherapy using melphalan alone.

3-Iodobenzylguanidine↗
PubMed1995

Dosimetric considerations in 131I-MIBG therapy for neuroblastoma in children.

Dosimetric calculations have been made for organ doses in patients receiving 131I-MIBG therapy as treatment for neuroblastoma. As well as whole body and liver dose, consideration has been given to dosimetry of organs (lung, urinary bladder) whose tolerance may become treatment limiting when 131I-MIBG is given as part of combined modality therapy. Data from both adults and children receiving radiolabelled MIBG for diagnostic or therapeutic purposes have been compared in constructing dosimetry models for children. A recently published urodynamic model has been used in the estimation of radiation dose to the bladder. The results show that liver and lung may receive doses greater than the average total body dose (0.58 mGy MBq-1 and 0.35 mGy MBq-1, respectively, as compared with 0.25 mGy MBq-1 to the whole body). The organ dose estimates do not differ greatly from previous analyses except in the case of the bladder for which the new modelling studies have resulted in lower dose estimates (0.76 mGy MBq-1 administered, for dose to bladder surface from bladder contents) than in some published series. This may result from differing assumptions regarding parameters such as bladder content and urine flow rate, an enhanced fluid intake being assumed in the present bladder dose estimates. Average doses to the bladder wall from the contents were estimated to be 7.4-11.3% of the surface doses. The urodynamic modelling analysis shows that the bladder could receive a much greater dose (by an order of magnitude) in patients who were inadequately hydrated or had impaired renal function.

3-Iodobenzylguanidine↗
PubMed1993

The design and construction of a central radiopharmacy.

Following an inspection by the Medicines Control Agency (MCA) of the existing radiopharmacy, it was necessary to design and build a new facility at the Western Infirmary to supply radiopharmaceuticals for patient use throughout the West of Scotland. This is one of the largest radiopharmacies in Europe, supplying some 40,000 patient doses per year prepared using both closed and open procedures. The design parameters and construction details of the new facility are presented.

Facility Design and Construction↗
PubMed1991

Radiological protection guidance for radioactive patients--new data for therapeutic 131I.

Patients leaving hospital after 131I treatment for thyrotoxicosis face restrictions on their contact with other members of the public. These restrictions depend on the level of residual body radioactivity which for practical purposes can be taken to be almost entirely in the thyroid gland. This study provides an appropriate data base from which to draw advice to patients consistent with current radiological protection requirements in terms of the duration of these restrictions. Thyroidal retention of 131I was measured in 77 thyrotoxic patients over a period of 1-50 days after a first therapeutic administration of the radionuclide. Mean 131I activity in the gland (+/- S.D.) at 1 day was 56.1 +/- 11.1% of the administered dose activity and thereafter retention followed a single exponential decay pattern with a mean effective half-life (+/- S.E.M.) of 6.35 +/- 0.14 days. In patients who required further 131I therapy, there was evidence that retention could be markedly reduced if there was virtual ablation of thyroid tissue. It is proposed that these retention data can be used to determine body radioactivity at any interval after the administration of 131I for treatment of thyrotoxicosis, thus obviating the need for serial measurements in every individual patient.

Adult↗
PubMed1991

Plasma gastrin, daytime intragastric pH, and nocturnal acid output before and at 1 and 7 months after eradication of Helicobacter pylori in duodenal ulcer subjects.

Nine patients with Helicobacter pylori-related antral gastritis and history of duodenal ulceration were studied before and at 1 and 7 months after eradication of the infection by a 4-week course of tripotassium dicitrato bismuthate, metronidazole, and amoxycillin. The median basal gastrin concentration before eradication was 30 ng/l (range, 20-60) and fell to 20 ng/l (5-20) at 1 month (p less than 0.02) and 15 ng/l (5-20) at 7 months (p less than 0.01) after eradication. The integrated gastrin response to a peptide meal was 3650 ng/l.min (range, 1875-6025) before treatment compared with 1800 ng/l.min (range, 1200-3075) at 1 month (p less than 0.01) and 1312 ng/l.min (875-2625) at 7 months (p less than 0.03). Daytime intragastric pH (0900-2100 h) was similar before treatment (median, 1.4; range, 1.1-2.1) and at 1 month (1.4; 1.1-2.3) and 7 months (1.4; 1-2.2) after eradication. In five of the patients nighttime acid output (2300-0900 h) was also studied and was similar before (median, 86 mmol/10 h; range, 52-114) and at 1 month (76 mmol/10 h; 50-143) and 7 months (94 mmol/10 h; 63-106) after eradication. In conclusion, eradication of H. pylori is accompanied by a sustained fall in serum gastrin concentrations but is not accompanied by an early or late reduction of daytime intragastric acidity or nighttime acid output.

Adult↗
PubMed1990

Tumor spheroid model for the biologically targeted radiotherapy of neuroblastoma micrometastases.

Neuroblastoma is a pediatric malignancy with a poor prognosis at least partly attributable to an early pattern of dissemination. New approaches to treatment of micrometastases include targeted radiotherapy using radiolabeled antibodies or molecules which are taken up preferentially by tumor cells. Multicellular tumor spheroids (MTS) resemble micrometastases during the avascular phase of their development. A human neuroblastoma cell line (NBl-G) was grown as MTS and incubated briefly with a radiolabeled monoclonal antibody (131I-UJ13A) directed against neuroectodermal antigens. Spheroid response was evaluated in terms of regrowth delay or proportion sterilized. A dose-response relationship was demonstrated in terms of 131I activity or duration of incubation. Control experiments using unlabeled UJ13A, radiolabeled nonspecific antibody (T2.10), radiolabeled human serum albumin, and radiolabeled sodium iodide showed these to be relatively ineffective compared to 131I-UJ13A. The cell line NBl-G grown as MTS has also been found to preferentially accumulate the radiolabeled catecholamine precursor molecule m-[131I]iodobenzylguanidine compared to cell lines derived from other tumor types. NBl-G cells grown as MTS provide a promising laboratory model for targeted radiotherapy of neuroblastoma micrometastases using radiolabeled antibodies or m-iodobenzylguanidine.

Antibodies, Monoclonal↗
PubMed1990

Fifteen years of radiological protection experience in a regional radiopharmacy.

Radiological protection experience in a regional radiopharmacy, currently handling 28.5 TBq (770 Ci) 99mTc y-1, is reviewed for the period 1974-1988. The results of personnel monitoring have shown a downward trend (by more than a factor of two) in radiation exposure of individual staff members, despite the workload per person [6000 GBq (162 Ci) 99mTc y-1] remaining virtually constant. Adequate staff selection and training contribute to the reduction in dose. A significant reduction in dose to the eyes was achieved by installing lead glass screens in the radiopharmacy work stations, and tungsten syringe shields reduced radiation dose to the hands. The use of commercially available kits for producing 99mTc radiopharmaceuticals, rather than relying on in-house preparations that require more operator handling, has also contributed to reduction in radiation exposure. Internal contamination of staff members with 125I was markedly reduced when the practice of sub-dispensing high-specific activity solutions of the radionuclide was discontinued. Annual doses from external radiation currently average less than 6 mSv (600 mrem) to the trunk, less than 7 mSv (700 mrem) to the eyes, and 50 mSv (5 rem) to the hands. Internal contamination of personnel with 125I, 131I, and 99mTc, as detected by thyroid and whole-body monitoring, contributed less than 65 mSv y-1 (6.5 rem) to the thyroid gland and less than 0.1 mSv y-1 (10 mrem) to the whole body.

Humans↗
PubMed1990

Investigation of factors affecting adhesion of 99Tcm labelled colloids to glass vials.

Factors which may possibly influence the adhesion of 99Tcm labelled colloid to glass vials were investigated. Of five colloids studied, two protein-free tin colloids were affected most by the problem, some 12-18% being lost by adhesion to the glass vial when the colloid was left resting on the bench, or 60-87% when it was rotated for a period of 4 h. The proportion of activity which adhered to the vial was dependent on the time the product had been contained within it, whether on the bench or rotated. Two of the colloids, both of which contained protein, were affected only slightly by the problem, one being a tin colloid and the other a sulphur colloid. An antimony sulphide colloid, which contained no added protein, was virtually unaffected by the problem. The degree of adhesion was not related to the pH of the product, nor to the temperature at which the product was stored, nor to the tendency of the colloid particles to grow in size upon vigorous agitation.

Colloids↗
PubMed1990

Effect of simulated intragastric haemorrhage on gastric acid secretion, gastric motility, and serum gastrin.

The majority of upper gastrointestinal bleeds stop spontaneously despite the low pH and proteolytic activity of gastric juice which inhibit coagulation and platelet aggregation. In order to investigate this paradox six healthy male volunteers received intragastric infusions of 160 ml autologous venous blood or 160 ml egg white acting as control in random order on separate days. Basal acid output was calculated before infusion, net acid secretion and gastric volume emptied were calculated after intragastric infusions. Serum gastrin concentrations were also measured before and after intragastric infusions and expressed as the integrated gastrin response. Basal acid output (mmol/h) was 4.7 (1.9) (mean (SEM)) before egg white infusion and 5.9 (2.6) before venous blood infusion. After egg white infusion net acid secretion (mmol/20 min) increased to 5.6 (3.1) compared with 2.3 (1.3) after venous blood infusion (p less than 0.05). The gastric volume emptied (ml/20 min) was less after venous blood infusion at 105 (28) compared with 321 (66) after egg white infusion (p less than 0.03). Integrated gastrin response was similar after venous blood and egg white infusion. When compared with an equivalent protein meal intragastric blood stimulates less acid secretion and delays gastric emptying. This effect may facilitate haemostasis after gastric bleeding.

Adult↗