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Biomedical subjects

C C Nimmon

Publications and source records attributed to C C Nimmon.

At least 37 records · Page 2Linked to original sources
PubMed1989

Validity of the mean parenchymal transit time as a screening test for the detection of functional renal artery stenosis in hypertensive patients.

Functional significance of renal artery stenosis (RAS) was assessed by 99Tcm-DTPA radionuclide scintigraphy, using the mean parenchymal transit time (MPTT) of the tracer as an index of renovascular disorder. Two groups of subjects were investigated retrospectively: eight normal live kidney donors; and 11 patients with hypertension, six with and five without significant RAS. MPTT was 171 +/- 11 s in the kidney donors, and there was a significantly prolonged MPTT in patients with RAS, 313 +/- 27 s (p less than 0.05). MPTT was also prolonged in three hypertensive patients with intrinsic renal disorders. The advantages and limitations of this technique are discussed. It is concluded that prolongation of MPTT can detect functionally significant renovascular disorder without pharmacological challenge.

Adult↗
PubMed1989

Irrigation and acute ureteric dilatation--as for ureteroscopy.

The effects of irrigation with sterile and infected saline after acute ureteric dilatation by graded Teflon dilators were evaluated renographically and histologically in minipigs. The minipig ureter was dilated from its normal calibre of 4 F to 10 F, and 100 ml of sterile or infected saline were then introduced from a height of 60 cm under gravity. One week after irrigation and dilatation the ipsilateral kidney was either functioning less than 10% or there was an obstructive nephropathy. Histology at 3 months suggested that extravasation of infected irrigating fluid was the most likely cause of ureteric stricture formation.

Animals↗
PubMed1988

Acute ureteric dilatation for ureteroscopy. An experimental study.

The effects of three methods of acute ureteric dilatation (by graded Teflon dilators, low and high pressure balloon dilators) were evaluated radiologically, renographically and histologically in minipigs. The minipig ureter was dilated from its normal calibre of 4 F to 10 F. All three methods caused upper urinary tract dilatation and an obstructive nephropathy which had not resolved 96 h after dilatation. Histology at 24 h showed destruction of the transitional epithelium, with inflammation throughout the ureteric wall. Four weeks after dilatation the ureter was still dilated and urothelial nests were seen in the lamina propria and in the muscle coats. There was no evidence of ischaemic necrosis or ureteric stricture formation. The implications of these findings for clinical practice are discussed.

Animals↗
PubMed1988

Technetium-99m MAG3, a comparison with iodine-123 and iodine-131 orthoiodohippurate, in patients with renal disorders.

A Phase I study in 12 patients with renal disorders compared the simultaneous clearances of 99mTc-labeled mercaptoacetyltriglycine (MAG3) and 131I-labeled orthoiodohippurate (OIH). The ratio of MAG3 to OIH clearance was 0.61 +/- 0.08 as a result of its smaller volume of distribution, ratio 0.65 +/- 0.09, for the clearance half-lives were similar, ratio 1.09 +/- 0.12. A Phase II study performed serially in 20 patients with equal doses of [99mTc]MAG3 and [123I]OIH gave images of equal quality. The relative renal functions were highly correlated (r = 0.97, p less than 0.001) and transit time analyses gave good correlations: parenchymal transit time index r = 0.81, p less than 0.05. We conclude that [99mTc]MAG3 has some advantages over [99mTc]DTPA and is a suitable replacement for [123I]hippuran in routine renal imaging, relative function, and transit time studies, but not for the accurate estimation of the renal plasma flow.

Adult↗
PubMed1988

Kinetic analysis and probability mapping applied to the detection of ovarian cancer by radioimmunoscintigraphy.

Kinetic analysis with probability mapping is an objective method of serial image analysis applicable to radioimmunoscintigraphy. The technique is described and subjected to clinical testing by comparing the prediction of biopsy histology from the probability map in patients coming to operation. In those with ovarian cancer undergoing second-look laparotomy after completing full courses of chemotherapy, the prediction of histology in 108 biopsy sites was 45 true positives and 38 true negatives, sensitivity 80%, specificity 73%, accuracy 77% p less than 0.001. In patients with tumors less than 2 cm diameter, 41 biopsy sites were predicted with a specificity of 78% and an accuracy of 76%, p less than 0.01. The technique is reducing the need for second-look laparotomy in patients with subclinical and subradiological disease. Such disease is suitable for intraperitoneal radioimmunotherapy.

Adult↗
PubMed1988

Ocular radioimmunoscintigraphy: sensitivity and practical considerations.

Ocular radioimmunoscintigraphy was performed in 20 patients using 99mTc-labeled monoclonal antibody 225.28S, F(ab')2 fragments. Radioimmunoscintigraphy was positive in 13 patients and the diagnosis of ocular melanoma was confirmed by enucleation of the eye or clinical follow-up. Scintigraphy was positive in one patient with lymph node metastasis from an ocular melanoma. In six patients immunoscintigraphy was negative. Using this technique a sensitivity of 92.8% was achieved for detecting ocular melanomas. Single photon emission tomography helped to separate the lesions situated in the nasal quadrant of the eye from the adjacent nasopharyngeal activity. With appropriate imaging techniques small tumors of the order of 3 x 5 x 3 mm could be detected clearly.

Antibodies, Monoclonal↗
PubMed1987

Radionuclide evaluation pre- and postextracorporeal shock wave lithotripsy for renal calculi.

Forty-two patients were evaluated pre- and postextracorporeal shock wave lithotripsy (ESWL) using [99mTc]DTPA renography. A quantitative evaluation showed that the relative renal function decreased 2-3 days post-ESWL on the treated side, and the parenchymal transit time index (PTTI) increased 2-3 days post-ESWL (p less than 0.001) on the treated side and returned to the pretreatment level by 3 wk post-ESWL. The untreated side showed an increase in PTTI 2-3 days post-ESWL (p less than 0.01), which returned to normal by 3 wk post-ESWL. A significantly greater increase in PTTI was seen in patients who received greater than 1,000 shocks as compared with those who received less than 1,000 shocks. Five patients developed obstructing uropathy post-ESWL, when stone fragments caused ureteric obstruction.

Humans↗
PubMed1986

Total and intrarenal flow distribution in healthy subjects: technique, acute effects of ibopamine and of indoramin.

A technique is described for measuring an index of cardiac output, total and individual renal plasma flow, cortical and juxtamedullary nephron flow non-invasively in man with a single injection of 123I-o-iodohippurate. Ibopamine, a dopamine analogue, was administered orally, 200 and 600 mg, in a double-blind, placebo-controlled cross-over study in 6 healthy subjects. No change in pulse, blood pressure, cardiac output, urea, creatinine or electrolytes was seen. Ibopamine reduced effective renal plasma flow and cortical nephron flow and increased urine flow significantly. This may be due to differential vasoconstrictor and vasodilator effects on the two populations of nephrons. Indoramin, and alpha-1 postsynaptic adrenoceptor blocker, was administered orally, 50 mg, in a double-blind, placebo-controlled cross-over study in 14 healthy young males. No change in pulse, cardiac output, urea, creatinine or electrolytes was seen. Indoramin significantly reduced upright but not supine blood pressure and significantly increased effective renal plasma flow. Cortical nephron flow and juxtamedullary nephron flow tended to rise. Plasma renin activity was significantly elevated although there was no change in urinary sodium output. The effect of drugs on intrarenal blood flow distribution may be relevant to the management of essential hypertension.

Adult↗
PubMed1986

A prospective study of 123I-labeled monoclonal antibody imaging in ovarian cancer.

Thirty patients presenting with a pelvic mass were entered into a prospective study on the use of radioimmunoscintigraphy with the 123I-labeled monoclonal antibody HMFG2. The imaging data was obtained without knowledge of the clinical data and compared with subsequent surgical findings. A false-positive diagnosis of ovarian cancer was made in five of ten patients subsequently shown not to have ovarian cancer; thus the technique cannot be used as a screening test. A true-positive diagnosis was made in 19 out of 20 patients shown subsequently to have ovarian cancer. In 18 of these patients the distribution of uptake closely fitted the surgical findings. Methods of improving these results are described. In conclusion, radioimmunoscintigraphy is of no use in determining whether a pelvic mass is due to ovarian cancer, but has benefit in the evaluation of chemotherapy and may, in the future, prevent the need for second-look operations in some circumstances.

Antibodies, Monoclonal↗
PubMed1985

123I radioiodinated antibody imaging of occult ovarian cancer.

A monoclonal antibody HMFG2 labeled with iodine 123 (123I) was given to a patient who had ovarian cancer. The scan taken 18 hours after administration of the antibody demonstrated the presence and the position of residual tumor in the pelvis that was not previously detected by ultrasonography and computerized tomography (CT) scanning. The presence of tumor was confirmed by surgery and histologic as well as immunoperoxidase examination of resected tissues. The tumor mass found was less than 0.8 cm in diameter. It is concluded that, in the search for residual or early ovarian cancer in the pelvis, monoclonal antibody scanning using 123I-labeled HMFG2 can complement ultrasonography and CT scanning.

Adenocarcinoma↗
PubMed1985

Cerebral blood flow in hypertensive patients with cerebrovascular disease: technique for measurement and effect of captopril.

Nineteen patients with unilateral cerebrovascular disease underwent cerebral blood flow (CBF) measurements; ten had been receiving conventional therapy and then were studied after treatment with captopril without or with a diuretic and nine on conventional therapy were studied twice as a control group. CBF (ml min-1) was measured after an intravenous injection of 99Tcm-labelled patient's red cells with a computer linked gamma camera over the vertex and a probe over the aorta. With deconvolution analysis regional CBF is given by regional cerebral volume divided by regional mean transit time. Results in the captopril group showed on average a 10% fall in mean blood pressure and a 10% rise in blood flow to the affected hemisphere. In the control group there was on average a 4% fall in pressure, together with an 11% fall in CBF to the affected hemisphere. Captopril appears to maintain autoregulation in cerebrovascular disease.

Adult↗
PubMed1984

Radioimmunodiagnosis of ovarian cancer using 123I-labelled, tumor-associated monoclonal antibodies.

Monoclonal antibodies to epithelial cells, antigenic determinants labelled with I123 and I125, were administered to 10 immunodeficient mice bearing subcutaneous xenografts of human ovarian cancer. Radio scans of the body taken with a gamma camera at various time intervals demonstrated the presence of the cancer in all the mice. The smallest detectable tumor was approximately 1 mm in diameter. In a subsequent clinical study using 123I-labelled monoclonal antibodies in 10 patients with ovarian cancer, tumor detection was achieved in 8 patients, with tumor uptake of labelled antibody ranging between 0.2-2.6%. As a complementary method to existing forms of diagnosis, the targeting of monoclonal antibodies to ovarian cancer cells in vivo raises the hope of achieving early diagnosis in otherwise undetectable ovarian cancer, and provides encouragement to the concept of selective therapy in oncology.

Adenocarcinoma↗