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Biomedical subjects

S J Mather

Publications and source records attributed to S J Mather.

At least 55 records · Page 3Linked to original sources
PubMed1996

Posterior urethral valves in male infants and newborns: detection with US of the urethra before and during voiding.

PURPOSE: To document the appearance and width of the posterior urethra with transperineal ultrasound (US) before and during voiding in male infants and newborns with posterior urethral valves. MATERIALS AND METHODS: Thirty-three patients with bilateral hydronephrosis underwent prospective transabdominal and transperineal US. RESULTS: Fifteen patients had proved posterior urethral valves (obstructed group); 18 patients had no obstruction (unobstructed group). In the obstructed group, the median posterior urethral width was 4.5 mm before and 10.0 mm during voiding. In the unobstructed group, the median posterior urethral width was 1.0 mm (P = .046) before and 4.0 mm (P < .001) during voiding. Bladder wall thickness was 3.0-7.6 mm (obstructed group) and 2.0-5.0 mm (unobstructed group; P < .001). With a posterior urethral diameter of at least 6 mm during voiding as a criterion for transperineal US diagnosis of obstruction, sensitivity was 100%; specificity, 89%; and positive predictive value, 88%. CONCLUSION: Transperineal voiding US is noninvasive and useful in diagnosing posterior urethral valves.

Case-Control Studies↗
PubMed1996

Breast cancer 99mTc SM3 radioimmunoscintigraphy.

99mTc SM3 radioimmunoscintigraphy is combined with kinetic analysis and probability mapping using a change detection algorithm to investigate axillary node involvement before primary surgery in patients with breast cancer. Whereas planar imaging was unsuccessful, axillary node involvement was correctly determined in 11 out of 13 patients 6 out of 7 true negatives and 5 out of 6 true positives down to 0.35 grams. A prospective study is underway.

Adult↗
PubMed1996

Radiolabelled cytokines.

Cytokines are soluble factors that act as intercellular messenger between cells of the immune system. They act by binding to specific receptors that are normally poorly expressed on effector cells but in disease are upregulated following cell activation. Several cytokine/cytokine receptor systems operate in infection, autoimmunity, cancer and other pathological conditions. This enhanced receptor expression can form a target for the diagnosis of the disease process. Many cytokines have characteristics which favour their use as radiopharmaceuticals; these include a relatively low molecular weight, short half life and rapid plasma clearance, binding of high affinity to specific receptors, ready availability due to recombinant technology and lack of immunogenicity. Radiolabelled cytokines are therefore a promising class of peptide radiopharmaceuticals that may have diagnostic potential in a number of pathological conditions.

Animals↗
PubMed1995

Inadvertent extradural insertion of an internal jugular catheter in an infant.

We present an unusual complication of left internal jugular vein catheterization in an 11-week-old infant which we believe has not been described previously. After failed subclavian catheterization, a left internal jugular catheter was placed without apparent difficulty. Confirmatory chest x-ray revealed that the tip of the catheter was in the extradural space.

Catheterization, Central Venous↗
PubMed1995

Postoperative morphine requirements, nausea and vomiting following anaesthesia for tonsillectomy. Comparison of intravenous morphine and non-opioid analgesic techniques.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to be as effective as opioid analgesia following tonsillectomy in children. Opioids are still frequently used but tonsillectomy is associated with a high incidence of vomiting. This study has attempted to assess postoperative analgesic consumption and nausea and vomiting after general anaesthesia for tonsillectomy using either paracetamol premedication, paracetamol plus a NSAID or intravenous morphine to provide postoperative analgesia. Some children required a rescue dose of morphine in the recovery room, including some who had received intravenous morphine at induction. Least supplementary morphine was required by those who had received paracetamol plus ketorolac. Postoperative nausea and vomiting was significantly less in the two groups which were not given intraoperative morphine. The number of vomiting incidents was also much less. We conclude that the preoperative administration of paracetamol alone provides satisfactory analgesia in many children but that supplementary analgesia is still required for some.

Acetaminophen↗
PubMed1993

Radioimmunoscintigraphy with technetium-99m-labelled monoclonal antibody, SM3, in gynaecological cancer.

Radioimmunoscintigraphy (RIS) with technetium-99m labelled SM3, a monoclonal antibody reacting with a polymorphic epithelial mucin glycoprotein core antigen, is evaluated. No adverse effects or thyroid uptake were observed. Studies in 45 patients (one twice) had a sensitivity for gynaecological malignancy of 100% (35/35) and a specificity of 73% (8/11), giving an overall accuracy of 93% (43/46). These results have led to the routine adoption of 99mTc RIS in the management of patients suspected of or having primary or recurrent gynaecological cancer.

Adult↗
PubMed1993

Radioimmunoscintigraphy with technetium-99m labelled monoclonal antibody, 1A3, in colorectal cancer.

This study of radioimmunoscintigraphy (RIS) was primarily undertaken to determine how the imaging results related to surgical findings. Technetium-99m radiolabelled 1A3, a monoclonal antibody against a columnar cell surface antigen, was used. No adverse effects or thyroid uptake was observed in 127 studies. The 85 primary colorectal cancers were all image positive. In the assessment of recurrent tumour in the abdomen or pelvis, the accuracy was 33/35 (94%), including true-positive findings in some whose serum carcinoembryonic antigen was normal. There was a positive predictive value for abdominal or pelvic recurrence of 92% and a negative predictive value of 100%, at a prevalence of 66%. In those patients whose liver was able to be evaluated, the accuracy was 72/79 (91%). There was a positive predictive value for liver metastases of 88% and a negative predictive value of 93%, at a prevalence of 32%. The simple procedure for labelling antibody with 99mTc and its ready availability allow a completed report to be given within 24 h of the request.

Adult↗
PubMed1993

Disturbed gastric and small bowel transit in severe idiopathic constipation.

Many patients with severe idiopathic constipation complain of upper gastrointestinal symptoms, and these often persist after subtotal colectomy. To determine if there is a disturbance of upper gastrointestinal motility in this condition, we have studied gastric emptying for solids (111In-containing pancake) and liquids (99mTc-containing orange juice) for a longer period after a meal (6 hr) than in previously reported gastric emptying studies. Small bowel transit for solids was also measured. All patients had emptied their colon the day before the study. Twelve women (mean age 36 years) with a bowel frequency of less than once per week, proven slow intestinal transit, and a normal diameter colon were studied. Twelve healthy controls (eight female and four male, mean age 33) were also studied. As a group the constipated patients demonstrated no statistically significant delay in emptying during the first 3 hr, although the emptying rate for three of 12 individuals fell outside the normal range. However, at 6 hr after ingestion of the meal, six of 10 patients had residual gastric contents greater than normal--up to 48% solid residue (median: 11% for patients and 0% for controls, P < 0.01) and 40% of liquid (median 9% vs 0%, P < 0.01). Three of four patients with upper gastrointestinal symptoms 6 hr after the meal had gastric retention of solids markedly outside the normal range (48%, 32%, and 16%; normal < 4%). Small bowel transit time was assessed as the time for the solid phase to pass from the duodenum to the cecum; the constipated patients demonstrated delayed transit (median: 75 vs 55 min, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Localization of neuroendocrine tumours and insulinomas using radiolabelled somatostatin analogues, 123I-Tyr3-octreotide and 111In-pentatreotide.

OBJECTIVE: A number of neoplasms are known to express somatostatin receptors; the use of somatostatin receptor imaging in their localization has recently been described, but the resolution and discrimination of the isotopes used remains sub-optimal. We have looked at the use of a new 111In-labelled analogue of somatostatin, pentatreotide, in the visualization and functional characterization of a number of neoplastic conditions. PATIENTS: Thirteen patients with proven neoplasms were scanned using this agent. Planar and single-photon-emission computerized tomographic (SPECT) images of the relevant part of the body were obtained using a gamma-camera at 10 minutes and 4 and 21 hours after injection of the radiopharmaceutical. In six patients (three carcinoid, three insulinomas) scanning was also performed using 123I-Tyr-3-octreotide. RESULTS: Primary tumours or metastases were visualized in six of the seven patients with neuroendocrine tumours, and three of six patients with insulinoma. One patient with an insulinoma who had a positive scan showed absent uptake when rescanned after tumour removal. A rise in blood glucose (more than twice basal) in response to octreotide was seen only in those insulinoma patients with positive scans. In cases where both 111In-pentratreotide and 123I-Tyr-3-octreotide scans were performed, both radiopharmaceuticals identified the same 4/6 tumours; however, tumour definition (reflecting high tumour to background ratio) was better with pentatreotide on the 21-hour images with minimum biliary and gut activity, allowing better resolution of the tumour image. CONCLUSION: It appears that 111In-pentatreotide scintigraphy is a rapid and safe procedure for the visualization of neuroendocrine tumours possessing somatostatin binding sites. A positive scan may be predictive of neuroendocrine responsiveness to octreotide therapy. In addition, it also appears that 111In-pentatreotide has superior kinetics compared to 123I-Tyr-3-octreotide, typically achieving more satisfactory tumour to background ratios, and may thus be more useful in the localization of endocrine tumours.

Adult↗
PubMed1993

Radioisotope determination of regional colonic transit in severe constipation: comparison with radio opaque markers.

Radio-opaque markers have a well established role in distinguishing between patients with normal and those with slow intestinal transit, but in the latter group their accuracy in defining the region of delay has not been established. To study regional colonic transit accurately the transit of a radioisotope labelled meal was determined and findings were compared with those of simultaneously ingested radio-opaque markers. Twelve healthy controls (mean age 33 years) and 12 severely constipated women (mean age 36 years, bowel frequency < once per week) were studied On day 1, a meal containing 10 MBq 111In bound to 0.7 mm resin microspheres was ingested. Subjects also ingested a set of radiologically distinguishable markers on three successive days. Abdominal scans were obtained three times daily for 7 days. Abdominal radiographs were obtained after 72 or 96 hours and again at 144 or 168 hours. Eight 'regions of interest' were created--one for the small bowel, six for the colon, and one for excreted stool. The constipated patients all showed colonic transit outside the normal range, with a variable site of delay demonstrated by time activity curves for each region. To provide a different measure of the effectiveness of colonic transport, the movement of the 'centre of mass' for the radioisotope and for the markers was then determined. The radioisotope and radiopaque marker methods gave similar results. At all times between 24 and 144 hours there was no significant difference for the position of the centre of mass between the radio-opaque and marker methods. At all times, however, the mean difference between the markers and the radioisotopes was positive, indicating that the center of mass of the markers was always head of that of the radioisotope. The mean difference between the methods was never greater than one region of interest, and ranged from 12 to 72% of one region of interest in the colon. The difference between these two methods could reach up to two colonic segments in certain patients at one time. Radioisotope ingestion provides accurate information about the transit through individual colonic regions because of the possibility of frequent observations and the clear delineation of the entire colon. Although these features were not obtained with radio-opaque markers, they are suitable as a screening test for the presence and pattern of colonic delay.

Adult↗
PubMed1993

Disturbed gastric emptying in the short bowel syndrome. Evidence for a 'colonic brake'.

Gastric emptying of liquid (orange juice containing technetium-99m (99mTc) labelled antimony sulphide colloid) and solid (570 kcal pancake containing 0.5 mm resin microspheres labelled with Indium-111 (111-In)) was measured in seven patients with jejunum and no colon (jejunal lengths 30-160 cm), six patients with jejunum in continuity with the colon (jejunal length 25-75 cm), and in 12 normal subjects. In patients with no colon early emptying of liquid was rapid (median 25% emptying: 7 v 25 min, no colon v normal, p < 0.05); early gastric emptying of solid was rapid in two (each with less than 100 cm jejunum) and normal in the other five. Gastric emptying of liquid and solid for patients with jejunum in continuity with the colon was normal for the first three hours. There was increased liquid and solid retained in the stomach at six hours in both groups of patients (p < 0.01). Small bowel transit time was faster than in normal subjects for liquid in both groups of patients (p < 0.05) and for solid in those with no colon (p < 0.05). Rapid gastric emptying of liquid may contribute to the large stomal output in patients with a high jejunostomy. Preservation of the colon after a major small intestinal resection exerts a braking effect on the rate of early gastric emptying of liquid.

Adult↗
PubMed1992

The mechanism of hepatic uptake of a radiolabelled monoclonal antibody.

Clinical and experimental scintigraphic studies have found that radiolabelled antibodies are not only taken up by tumour(s) but also by normal liver. The accumulation of radionuclides in this organ poses a major problem to the use of radiolabelled antibodies as diagnostic and therapeutic tools. In an attempt to understand the mechanism of hepatic uptake and clearance of radiolabelled antibodies, the intrahepatic biodistribution of an 111In-labelled MAb (HMFG1), was determined following i.v. administration to normal male rats. Two hours after administration the liver contained 15% of the injected dose, with most of the remaining radioactivity in the blood. The hepatic burden of the 111In MAb remained constant over the next 72 hr in the face of decreasing blood levels of radioactivity as well as its urinary and faecal excretion. At 2 and 72 hr after injection, 50% and 10% respectively of the hepatic radiolabel was due to blood borne antibody. Following a collagenase-cell isolation procedure, only 23% of the amount remaining in the liver at 2 hr was found to be cell-associated; 66% was lost during the cell isolation and purification procedure. Cellular uptake increased with time so that, by 72 hr after administration, 58% was cell-associated and 29% freely removable. At all timepoints, the parenchymal cells contained more activity than non-parenchymal cells. No evidence of antibody-receptor interactions could be obtained either in vivo or in cultures of hepatic parenchymal and non-parenchymal cells. Our data suggest that the bulk of the hepatic burden of 111In MAb results from extravascular pooling of the antibody.

Animals↗