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Biomedical subjects

M V Merrick

Publications and source records attributed to M V Merrick.

At least 55 records · Page 3Linked to original sources
PubMed1989

Value of the gamma camera renogram in the differential diagnosis of acute tubular necrosis and rejection in the early post-transplant period. Comparison with biopsy findings.

A group of 128 consecutive patients was identified on whom renal isotope studies had been performed during the first 2 months after renal transplantation and within 7 days of transplant biopsy. The prospective renogram and biopsy reports were reviewed and graded into 4 categories: severe rejection, predominant rejection, predominant acute tubular necrosis (ATN) and pure ATN. Two extreme patterns of renogram were identified: a sharp rise with a fast decline in the first min, attributed to ATN, and a slowly rising curve with no early peak occurring in severe rejection although not specific to this condition. There was a continuous intermediate spectrum. There was no inter-observer variation in gradings at the 2 ends of the spectrum. In the middle part the difference between 2 independent observers never exceeded more than 1 grade. There was good correlation between the biopsy and renogram gradings, with a discrepancy of more than 1 grade in only 5 patients; 2 of these, with severe rejection on the renogram, showed predominant ATN on biopsy, but the final clinical diagnosis was severe rejection (false positive biopsies). Two patients with biopsies showing severe rejection had a sharp initial up-slope in the renograms but a slower down-slope (over 4 min compared with 1 min in true ATN). With better definition of the criteria these renograms would not have been graded as ATN. There was 1 patient in whom no satisfactory explanation for the discrepancy was found (presumed false positive renogram). When properly defined criteria are used to interpret renograms, this simple test is at least as reliable as renal biopsy in differentiating ATN from rejection in the early post-transplant period, especially in the presence of anuria or severe oligurea.

Acute Kidney Injury↗
PubMed1989

Smoking delays gastric emptying of solids.

Oesophageal transit and gastric emptying of liquids and solids was measured in eight normal subjects with a single test meal containing In113 labelled water and an omelette labelled with Tc99m sulphur colloid. Each volunteer was studied, basally, whilst continuously smoking, and while chewing nicotine gum. Neither liquid, nor solid oesophageal transit were affected by smoking, or gum. Liquid gastric emptying occurred exponentially and clearance was not affected by smoking nor gum (mean basal t1/2 17.4 (2.7) (SEM) min, smoking t1/2 16.6 (7.4) min, gum t1/2 12.5 (2.9) min). Gastric emptying of solid had three components. An initial mean lag phase increased from 17.5 (2.7) min, to 27.5 (6.1) min (p less than 0.05) during smoking, but was not prolonged by nicotine gum (17.5 (1.1) min). A subsequent linear emptying phase was also slowed by smoking from a mean of 1.01 (0.15)% min to 0.80 (0.15)% min (p less than 0.05), but was not affected by nicotine gum, 1.06 (0.2)% min. A third complex phase of solid gastric emptying was not analysed. Smoking delays gastric emptying of solids, but not liquids; nicotine is not responsible for this effect. This observation may partly explain the adverse effect of smoking in patients with gastro-oesophageal reflux.

Adult↗
PubMed1989

Cerebral vascular transit time in Alzheimer's disease and Korsakoff's psychosis and its relation to cognitive function.

The cerebral vascular transit time of 17 patients with pre-senile dementia of the Alzheimer type (ATD), nine abstinent patients with alcoholic Korsakoff's psychosis (KOR), and ten age-matched controls was determined by the bolus intravenous injection of pertechnetate. A gamma camera was used to estimate the median transit time (MTT) of the radioactive bolus in a planar (non-tomographic) projection normal to the vertex. The spread of the bolus arriving at the aortic arch was measured independently by a single external detector over the chest, and correction made for the transit time of this input function in calculating the net MTT for the head. Both ATD and KOR groups showed lengthened net MTTs, compatible with reduced cerebral blood flow, and which were correlated with reduced cognitive function. It is concluded that the method employed gives a simple, inexpensive estimate of function-related blood flow to the brain in pre-senile dementia.

Aged↗
PubMed1988

131-I radioiodine therapy for hyperthyroidism in patients with Graves' disease, uninodular goitre and multinodular goitre.

We studied 201 consecutive patients who received a relatively fixed dose of radioiodine for the treatment of hyperthyroidism between the years 1981-6. Patients with Graves' disease (170) were initially treated with a mean (SE) dose of 369 (10) MBq 131-I with a remission rate of 94% at 6 months and a cumulative relapse rate of 12% at one year and 21% at 5 years. The cumulative incidence of hypothyroidism was 26% at 3 months, 55% at 6 months, 61% at 1 year and 66% at 5 years. Patients with a uninodular goitre (10) were initially treated with a mean (SE) dose of 438 (85) MBq 131-I with a remission rate of 100% at 6 months, without relapse at 1 year but relapsing in 17% at 5 years. The cumulative incidence of hypothyroidism was 26% at 3 months, 30% at 6 months, 40% at 1 year and 40% at 5 years. Patients with a multinodular goitre (21) were initially treated with a mean (SE) dose of 613 (77) MBq 131-I with a remission rate of 79% at 6 months and a cumulative relapse rate of 26% at 1 year and 39% at 5 years. The cumulative incidence of hypothyroidism was 5% at 3 months, 14% at 6 months, 24% at 1 year and 24% at 5 years.

Aged↗
PubMed1988

Cardiotoxicity of mitozantrone assessed by stress and resting nuclear ventriculography.

Fourteen patients with advanced breast cancer were treated with a combination of vincristine, mitozantrone and prednisolone. Before, during and after cessation of treatment radionuclide assessment of ventricular performance was obtained at rest, in response to cold pressor-induced stress and on recovery from stress. Six of 14 patients (46%) developed abnormalities of left ventricular ejection fraction (LVEF). One patient developed clinical signs of cardiac failure. Mitozantrone is an active agent in the treatment of advanced breast cancer but it can produce cardiotoxicity. In this particular middle-aged population, changes in LVEF occurred over a wide range of cumulative doses. Further investigation is required to determine the nature and prognosis of this iatrogenic toxicity.

Adult↗
PubMed1988

A reevaluation of an agent proposed for imaging oestrogen receptors: 17 alpha-[125I]-iodovinyl-11 beta-methoxyoestradiol-3-methyl ether ([125I]VMEME).

The metabolism of an iodinated steroid, 17 alpha-[125I]iodovinyl-11 beta-methoxyoestradiol-3-methyl ether ([125I]VMEME), previously proposed as a potential agent for imaging oestrogen receptor-containing tissues, has been studied and the conditions for synthesis and labelling redefined. It is confirmed that, although the compound does not itself have significant receptor-binding affinity, a metabolite is active. Because of its high solubility in fat and the consequential low contrast of small receptor-containing tumours, there is little prospect of successful early imaging of small axillary or internal mammary lymph node metastases from human breast cancer with this compound. Some more general implications of this finding are considered.

Animals↗
PubMed1987

Bone scintigraphy in testicular tumours.

The role of bone scintigraphy was assessed by follow-up and review of 61 patients with testicular tumours. Skeletal metastases were present in all five patients who died with seminoma and in two of the eight whose deaths were due to teratoma. The only patient with skeletal metastases to have a prolonged survival had a mixed teratoma/seminoma. Bone scintigraphy is indicated in patients with recurrence after radical treatment for seminoma and may be indicated in patients presenting with stage IV seminoma, to identify a sub-group with the worst prognosis. In other patients it is indicated only if there is a specific clinical suspicion of bone metastases.

Bone Neoplasms↗
PubMed1987

Absorbed dose from 14C xylose and 14C mannose.

Tissue distribution and excretion studies have been performed in rats and mice for up to 1 week after oral administration of 14C xylose and 14C mannose. The effective dose-equivalent is calculated to be 15 microSv/MBq for xylose and 120 microSv/MBq for mannose. Since there was no clearance of mannose during the period of the study, the effective dose-equivalent for mannose is almost entirely dependent upon the assumptions made about expected lifetime exposure.

Absorption↗
PubMed1987

Measurement of relative renal function. A comparison of methods and assessment of reproducibility.

A good correlation was found between relative uptake of 99Tcm dimercaptosuccinic acid (DMSA) and relative 131I orthoiodohippuric acid clearance in a group of 100 consecutive patients without evidence of renal failure. In the majority, attenuation correction was found to make no significant difference to relative function measurement. Those in whom it did could be readily identified by inspection of the posterior DMSA images at the time of examination. Two hundred patients were reviewed in whom serial studies had been performed over the previous 5 years. Differences in relative function greater than 5% indicated a high probability that a real change in renal function had occurred. We conclude that whilst renography and DMSA scintigraphy yield complementary information, relative function (L/L + R) can be measured equally well by either method, and the results are sufficiently reproducible to be clinically useful.

Humans↗
PubMed1987

Bone scintigraphy in symptomatic spondylolysis.

In 66 patients with back pain and suspected spondylolysis, the results of bone scintigraphy have been correlated with operative findings and clinical follow-up. Although bone scintigraphy is of little value for primary diagnosis, it helps to distinguish between those patients with established non-union of the defect, and those in whom healing is still progressing and who may benefit from immobilisation. We also found that increased uptake on the contralateral side to a unilateral spondylolysis is suggestive of impending fracture.

Adolescent↗
PubMed1986

The value of non-staging skeletal scintigraphy in breast cancer.

A series of 315 patients with histologically proven breast cancer had skeletal scintigraphy performed for defined reasons other than initial staging. Of these, 173 (55%) were found to be abnormal. The yield of abnormalities was highest (83%) in patients with bone pain or tenderness and radiographic evidence of metastases: 38% in those with bone pain or tenderness alone, 37% in asymptomatic patients with local or regional recurrence and 54% in those with non-bony metastases. The overall actuarial survival over a maximum follow-up of 9 years was significantly worse for those with abnormal scintigraphy. Non-staging skeletal scintigraphy is useful in detecting asymptomatic bone metastases at the time of local or regional recurrence or in the presence of non-bony metastases.

Actuarial Analysis↗
PubMed1986

A comparison of simplified and standard methods for the measurement of glomerular filtration rate and renal tubular function.

Two methods of measuring the clearance of 99Tcm DTPA, OIH and iothalamate were compared with standard techniques of measuring the clearance rates of inulin and sodium para-aminohippurate. The best correlation was between the clearance of subcutaneously injected radiolabelled iothalamate or 99Tcm DTPA and that of inulin. 99Tcm DTPA and 131I OIH clearances measured by a two blood sample technique did not give as good a correlation with inulin and PAH clearances respectively. When measurements of GFR and tubular function were repeated on the same patients the changes measured by inulin and PAH clearances did not correlate with those measured by the two blood sample technique using 99Tcm DTPA and OIH. Our results suggest that the clearance of subcutaneously injected iothalamate or DTPA can replace inulin clearance measurements. The two blood sample technique of measuring DTPA and OIH clearance does not directly reflect inulin and PAH clearance and is insufficiently reproducible to be used to follow changes in renal function.

Adult↗
PubMed1986

Bone scintigraphy in lung cancer: a reappraisal.

The prognostic significance of bone scintigraphy was investigated by following 587 consecutive patients with lung cancer, in whom this investigation had been performed, for up to 9 years, or until death. Survival was unrelated to age, sex or cell type. However, pain and abnormal bone scintigraphy were both independently associated with a significantly reduced survival compared with those who were free of pain or who had normal bone scintigraphy. These factors were cumulative. The association remained equally valid for all cell types. Claims that a single metastasis is not prognostically significant are unfounded. It is suggested that the results of some chemotherapy trials must be reconsidered in the light of present findings, because of the lack of adequate control groups; the results could be construed to show a beneficial effect only in patients with bone metastases and a poor prognosis, but little or no effect in patients with normal bone scintigraphy. As judged by clinical and radiological follow-up and post-mortem examination, skeletal scintigraphy in patients with lung cancer had a sensitivity of 0.89, a non-specificity (false positives/true negatives) of 0.00 and an accuracy of 0.78. With existing radiopharmaceuticals there is an irreducible residue of false negatives due to deposits which provoke little or no osteoblastic response. Bone scintigraphy is, thus, indicated in any patient with lung cancer with unexplained symptoms and whenever staging is required, because of the prognostic implications. It should precede other staging investigations because the high detection rate may render other tests unnecessary.

Adult↗
PubMed1985

Is bile acid malabsorption underdiagnosed? An evaluation of accuracy of diagnosis by measurement of SeHCAT retention.

The cause of intractable chronic diarrhoea was found to be malabsorption of bile acid in five out of 42 patients thought to have the irritable bowel syndrome, six out of 29 patients with persistent diarrhoea after surgery for peptic ulcer, 23 who had undergone small bowel resection, and two others. Specific treatment brought symptomatic relief. The diagnosis was established by measuring the proportion of SeHCAT, a synthetic bile salt, retained one week after oral administration of a tracer dose of less than 100 micrograms of the compound labelled with 40 kBq (1 microCi) of selenium-75. These results indicate that malabsorption of bile acid is a more common cause of chronic diarrhoea than is generally appreciated. Measurement of retention of SeHCAT is a simple, accurate, and acceptable means of establishing the diagnosis of this debilitating but treatable condition.

Adult↗
PubMed1985

Bladder cancer: the value of routine bone scintigraphy.

Two hundred and twenty-one patients with invasive bladder cancer had routine bone scintigraphy performed as part of tumour staging. The incidence of detectable metastases was 12%. Skeletal scintigraphy at diagnosis has a sensitivity of only 38%. The predictive value of a negative examination was 92%. These results suggest that skeletal scintigraphy is not indicated as a routine staging procedure in carcinoma of the bladder.

Aged↗