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Biomedical subjects

G J Teule

Publications and source records attributed to G J Teule.

At least 73 records · Page 4Linked to original sources
PubMed1993

Early treatment response in malignant lymphoma, as determined by planar fluorine-18-fluorodeoxyglucose scintigraphy.

Clinical oncology needs flexible techniques for routine monitoring of treatment response. We therefore compared planar 18F-fluorodeoxyglucose (FDG) with a conventional gamma-camera and a special collimator to 67Ga scintigraphy in 26 patients with malignant lymphoma during chemotherapy. The scintigraphic appearance of involved sites was essentially the same with both tracers: in patients eventually achieving complete remission, tracer distribution had normalized after two courses; high uptake reflected treatment failure; faint uptake was associated with variable outcome. For (re)staging, 67Ga may be preferable (higher contrast). To document the initial response, we performed FDG scintigraphy during the first course (n = 11). Effective treatment sharply reduced metabolic tumor activity within days and prior to volume response, whereas abnormal uptake persisted in treatment failure. Planar FDG scintigraphy may be a tool to assess the potentially prognostic initial response rate, preventing over-treatment and allowing a timely switch to more aggressive therapy.

Deoxyglucose↗
PubMed1992

Performance characteristics of a 511-keV collimator for imaging positron emitters with a standard gamma-camera.

Line-source experiments were conducted to assess the performance of a gamma-camera equipped with a specially designed 511-keV collimator for the planar imaging of positron emitters. The results were compared with the camera performance with routinely used collimators and radionuclides (thallium-201, technetium-99m and gallium-67). With positron emitters, scatter contributed less to the widening of the line spread function than with radionuclides emitting lower photon energies. These observations can be explained by the relative deterioration in the discrimination power of the gamma-camera to reject scattered radiation at low energies. Planar 511-keV imaging may provide relevant clinical information, as we showed by fluorodeoxyglucose studies in a patient with a myocardial infarction and in a patient with a malignant lymphoma. It is concluded that positron emitters can be effectively applied for planar imaging with the generally available gamma-cameras. This study implies that radiotracers developed for positron emission tomography may find a place in the practice of conventional nuclear medicine.

Adult↗
PubMed1992

Kinetics and dosimetry of iodine-131-labelled antibody fragments after local administration in patients with rectal cancer.

In 11 patients with rectal cancer, a mixture of F(ab')2 fragments of anti-carcinoembryonic antigen and anti-CA 19.9 labelled with a diagnostic dose of iodine-131 (3-10 MBq) was administered submucosally around the tumour. In this study, the local kinetics in and the dose to the rectal wall, the whole body kinetics and the effective dose equivalent are presented. The early disappearance of the activity from the injection spot was characterized by a T1/2 of 21 h. Initially, about 50% of the plasma activity was due to free 131I. After 4 h, the plasma activity was almost completely protein bound (86%). Maximum plasma activity was observed after the 2nd day. From 72 h p.i., the plasma activity decreased with a T1/2 of 53 h. In the first 24 h, 14% of the injected dose was excreted in the urine and within 4 days about half of the administered activity. The absorbed radiation dose to the rectal wall was estimated to be 0.2 Gy/MBq, presuming a 20 cm3 distribution volume. The dose to the bone marrow was 0.2 mGy/MBq or 0.4 mGy/MBq, assuming a homogeneous tracer distribution or equal blood and bone marrow activity concentrations, respectively. The effective dose equivalent is 1.9 mSv/MBq, mainly determined by the dose to the rectal wall and to a lesser extent by the dose to the remaining body. Postulating comparable kinetics, 123I- or 111In- or 99mTc-labelled fragments would result in 4-25-fold lower effective dose equivalents.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Transport of 67Ga and 111In across a membrane. Role of plasma binding and concentration gradients.

If i.v. injected radiogallium does not firmly bind to circulating transferrin in plasma, the transvascular transport of the radionuclide may be affected by diffusion of unbound radionuclide and interstitial transferrin, and may therefore not be specific for transferrin transport. Using equilibrium dialysis, the avidity of 67Ga and 111In to bind to plasma transferrin was compared by evaluating transport of unbound radionuclide across a semipermeable membrane, as a function of the plasma (transferrin) concentration gradient. One chamber of a dialysis cell was filled with human plasma and 67Ga or 111In, and the other, separated by the membrane, with increasing concentrations of plasma in normal saline. The half-time (mean +/- S.D.) for reaching equilibrium between the chambers decreased (P less than 0.05) for 67Ga from 13.1 +/- 3.3 to 4.9 +/- 1.6, 3.7 +/- 1.2 and 3.0 +/- 0.5 h, at plasma concentrations of 0, 25, 50 and 100%, respectively. The equilibrium half-time for 111In did not fall at increasing plasma concentrations and was higher (P less than 0.005) than for 67Ga at 25 to 100% plasma. Hence, 67Ga is not as avidly bound to plasma transferrin as 111In, since, in contrast to 111In, dissociation of the 67Ga-transferrin complex and transmembrane diffusion of unbound 67Ga increases when the plasma transferrin concentration gradient decreases. In vivo, the transvascular transport of 67Ga may be influenced by diffusion of unbound radionuclide, depending on the interstitial transferrin concentration, and may not be a specific indicator of transvascular protein transport.

Biological Transport↗
PubMed1991

Qualitative and quantitative kinetics of submucosally administered antibody fragments in patients with rectal carcinoma: the detection of lymph node metastasis in relation to local tracer diffusion.

Immunoscintigraphy after submucosal administration of a mixture of 131I-anti-CEA and 131I-anti-CA-19-9 around the tumor in patients with rectal carcinoma may improve pre-operative staging and may contribute to the selection of patients eligible for local treatment. However, visual discrimination of local lymph node metastasis appears unreliable, partly because of scatter from the injection site and substantial diffusion of the radiotracer into the interstitium. Analysis of the diffusion profile, however, may improve the sensitivity and accuracy of this immunoscintigraphic approach.

Aged↗
PubMed1991

Total body blood volume redistribution in porcine E. coli septic shock: effect of volume loading, dobutamine, and norepinephrine.

The purpose of the present study was to determine the effect of volume loading alone (CONTR) vs. volume loading in combination with dobutamine (DOBU) or norepinephrine (NOR) on total body blood volume distribution in septic shock. After instrumentation, injection of in vitro labelled 99mTc red blood cells, and baseline measurements, anesthetized, ventilated pigs (n = 21) received 3-4.10(8).kg-1 live E. coli bacteria intravenously. Images of thorax, abdomen, and hindlimb were obtained by using a gamma camera simultaneously with hemodynamic measurements. E. coli infusion resulted in a decrease in arterial pressure, ventricular filling pressures, and cardiac output with a concomitant increase in pulmonary arterial pressure. Blood volume was redistributed from the heart, lungs, spleen, abdomen, and leg to the liver. After randomization, the CONTR group (I, n = 5) was subjected to volume loading, and treatment groups (each n = 8) received volume loading in combination with DOBU (group II, 5-10 micrograms/kg/min) or NOR (group III, 0.25-0.50 micrograms/kg/min). As compared to volume loading alone, DOBU and NOR increased cardiac output but only NOR restored arterial pressure. Volume loading increased blood volume in all regions studied; however, it was unequally distributed amongst organs with a preference for the liver. Neither DOBU nor NOR influenced the partitioning of the infused volume between organs. However, NOR prevented pooling of blood in the leg.

Animals↗
PubMed1989

Sucralphate-technetium scintigraphy in inflammatory bowel disease: experience in 23 patients.

Serial abdominal scanning after the oral administration of sucralphate-99mTc was performed in order to determine the extent of active inflammatory bowel disease in 15 patients with Crohn's disease and in 8 patients with ulcerative colitis. Scintigraphic data were compared with those obtained by endoscopy and radiology in all patients. True positive scans were obtained in 6 (40%) patients with Crohn's disease and in 3 (38%) patients with ulcerative colitis. Overall, sensitivity was higher in colonic disease than that in ileal disease. In 4 (17%) patients, false negative scans were obtained and in the remaining 10 (44%) patients, localisation of the inflammatory bowel disease by the isotope was completely inaccurate. Since sensitivity of the sucralphate-99mTc scintigraphy appears to be low, its widespread use in the screening for inflammatory bowel disease or in assessing the extent of disease involvement cannot be advocated at this moment.

Adult↗
PubMed1988

A prospective study on the dose dependency of cardiotoxicity induced by mitomycin C.

Since 1975 mitomycin C (MMC) has been suggested to be cardiotoxic, especially when combined with or given following doxorubicin. Data on dose dependency or incidence concerning this side effect were not known. We have initiated a prospective study to obtain some more data on these subjects. Forty-four MMC-treated patients were studied, 37 of them could be evaluated. All patients were studied by repeated physical examinations, chest X-rays, electro- and echocardiography and radionuclide left ventricular ejection fraction (EF) determinations. The results were evaluated per cumulative dose level. One of the patients developed cardiac failure after 30 mg m-2 MMC and only 150 mg m-2 doxorubicin. The cardiac failure was predicted by a drop in EF determined during a cold pressor test. None of the other patients developed clinical cardiotoxicity, nor did the studied parameters change. The literature on this subject was also reviewed. Based on the combined data from the present study and the literature, we suggest that MMC-related cardiotoxicity is dose dependent, occurring at cumulative dose levels of 30 mg m-2 or more, mainly in patients also (previously or simultaneously) treated with doxorubicin. The incidence is likely to be less than 10% even for this risk group.

Adult↗
PubMed1988

Biventricular performance during volume loading in patients with early septic shock, with emphasis on the right ventricle: a combined hemodynamic and radionuclide study.

The cardiac response to a rapid volume infusion was studied in 18 patients with septic shock accompanied by pulmonary hypertension. Right and left ventricular ejection fractions were measured, and right and left ventricular volume indices were calculated from ejection fractions and stroke volumes before and 30 minutes after the start of the infusion. Responders (13 patients) showed an increase in stroke volume index (SVI) as a result of a mean 30% increase in right ventricular end-diastolic volume index (RVEDVI) and a mean 17% increase in left ventricular end-diastolic volume index (LVEDVI) during volume loading. In the nonresponders (five patients) fluid loading resulted in a decreased or unchanged SVI; this was accompanied by a 7% increase in RVEDVI but no change in LVEDVI, although both the central venous pressure and pulmonary capillary wedge pressure increased. At baseline, nonresponders differed from responders as evidenced by a high central venous pressure and RVEDVI but a lower mean arterial pressure: thus, right ventricular coronary perfusion pressure was lower and right ventricular wall stress may have been higher. Mean pulmonary artery pressure did not differ between the groups. Our data suggest that in some patients with septic shock volume loading does not result in increased forward flow because of right ventricular failure associated with pulmonary hypertension and coronary hypotension.

Fluid Therapy↗
PubMed1987

Increased systemic microvascular albumin flux in septic shock.

Lymph/plasma (L/P) albumin ratios were followed in a patient with a traumatic thoracic duct lymph fistula, during septic shock when lymph flow was high and at recovery when lymph flow was low. Higher albumin ratios were found during the former. On both occasions, the P-L difference of radioactive counts/min per gram was followed for 6 h after i.v. injection of 51Cr human serum albumin (HSA). Equilibration half times between plasma and lymph amounted to 0.85 h during septic shock and 2.49 h at recovery. The data indicate that systemic microvascular albumin flux had increased during shock in our patient. Increased permeability may have been responsible.

Aged↗
PubMed1987

The immediate effect of nitroglycerin on total body blood volume distribution in patients with congestive heart failure: a non-invasive study.

The effect of sublingually administered nitroglycerin (0.5 mg) on distribution of blood volume in 16 patients with congestive heart failure (NYHA class II and III), randomly assigned to placebo (N = 8) or nitroglycerin (N = 8) was studied 20 minutes after in vivo labelling of red blood cells with 99m-Tc pertechnetate. Count rates over thorax, abdomen and legs were collected with a large field gamma camera and expressed as percentage changes of baseline value. Changes in count rates, averaged for 5, 10 and 15 minutes after drug administration showed a significant decrease in the nitroglycerin group as compared to the placebo group over the thorax (mean 5%, P less than 0.01) and over the liver (mean 5%, P less than 0.05) and a significant increase over the abdomen (mean 4%, P less than 0.01) and the legs (mean 9%, P less than 0.01). After nitroglycerin, the changes in pulmonary activity were variable and did not differ from the placebo group. These results indicate that nitroglycerin causes a redistribution of blood volume in patients with congestive heart failure. An increase in the vascular capacitance in the abdomen and legs may be responsible for a decrease of blood volume of the thorax and the liver in these patients.

Abdomen↗
PubMed1987

Influence of left ventricular function on changes in plasma volume during acetate and bicarbonate dialysis.

The effect of left ventricular function on changes in plasma volume during acetate and bicarbonate dialysis was studied in stable, chronic dialysis patients. Preservation of plasma volume in patients with a normal left ventricular function (mean circumferential fibre shortening velocity (VcF) greater than or equal to 1 circ/s) was significantly less during the first hour of acetate dialysis than during bicarbonate dialysis. However, in patients with impaired left ventricular function (VcF less than 1 circ/s) the decrease in plasma volume was more pronounced during acetate when compared to bicarbonate dialysis. This resulted in a decreased ultrafiltration volume and haemodynamic instability in these patients during acetate dialysis. The fibre shortening velocity increased during acetate and bicarbonate dialysis in patients with a normal left ventricular function, whereas in patients with impaired left ventricular function fibre shortening velocity increased only during bicarbonate dialysis. In conclusion, in patients with an impaired left ventricular function, bicarbonate is preferable to acetate in chronic dialysis.

Acetates↗
PubMed1987

Effects of vasodilators prostaglandin E1 and methylprednisolone on pulmonary hypertension and right ventricular performance during volume loading in porcine septic shock: a combined invasive and radionuclide study.

In 16 anesthetized pigs the cardiovascular effects of prostaglandin E1 and methylprednisolone (MPS) during E. coli sepsis were studied. Gated blood pool scans and hemodynamic studies were simultaneously performed. A control group, group I (n = 4), received volume loading alone; groups II, III, and IV received (each n = 4) volume loading after intravenous administration of MPS, prostaglandin E1, and both MPS and prostaglandin E1, respectively. Groups were formed by randomization, such that the effects of prostaglandin E1 (0.1 microgram/kg/min) and MPS (30 mg/kg) could be analyzed separately and in combination. Eight animals treated with prostaglandin E1 were compared with eight animals not receiving prostaglandin E1. The same method was applied to the MPS group. E. coli infusion resulted in an abrupt increase in pulmonary arterial pressure while systemic blood pressure gradually fell. Cardiac output decreased. Gated blood pool studies showed an increase in right ventricular end-diastolic volume and a decrease in right ventricular ejection fraction. Consequently, right-to-left ventricular end-diastolic volume ratio increased. Pulmonary arterial pressure was lowered in the treatment groups compared to control group. During volume loading right ventricular ejection fraction improved in the prostaglandin E1 group but remained low in the MPS group. Compared to control group, cardiac output did not change and mean systemic arterial pressure significantly decreased in the prostaglandin E1 group. Treatment with prostaglandin E1, MPS, or both drugs and volume loading did not reveal any difference between the four groups with respect to cardiac output, right and left ventricular volumes, and left ventricular ejection fraction. The present study indicates that in a porcine model of E. coli septic shock with acute pulmonary hypertension, prostaglandin E1 and MPS treatment decrease pulmonary vascular resistance but also systemic vascular resistance. Prior to and during volume loading right ventricular ejection fraction increased in the prostaglandin E1 group. However, neither prostaglandin E1 nor MPS improved right ventricular performance and forward flow during volume loading.

Alprostadil↗
PubMed1987

Volume expansion, dobutamine and noradrenaline for treatment of right ventricular dysfunction in porcine septic shock: a combined invasive and radionuclide study.

The purposes of the present study were 1) to explore if volume loading in combination with dobutamine or noradrenaline would be superior to volume loading alone in the treatment of right ventricular (RV) dysfunction in septic shock complicated by acute pulmonary hypertension and 2) to determine whether noradrenaline would be superior to dobutamine because of its vasoconstrictor effects on the peripheral circulation, resulting in increased RV coronary perfusion pressure. Experiments were performed on 21 anesthetized, ventilated pigs. Gated blood pool studies and hemodynamic measurements were performed simultaneously. All animals were given 3-4 X 10(8)/kg live E. coli bacteria, resulting in an abrupt increase in pulmonary arterial pressure and a decrease in arterial pressure, cardiac output, and RV ejection fraction. Right ventricular end-systolic volume was unchanged; RV end-diastolic volume and RV coronary perfusion pressure fell. After randomization, the control group (I, n = 5) was subjected to volume loading, and treatment groups (each n = 8) received volume loading in combination with dobutamine (group II, 5-10 micrograms/kg/min) or noradrenaline (group III, 0.25-0.50 micrograms/kg/min). In contrast to volume loading alone, dobutamine and noradrenaline increased cardiac output and RV ejection fraction, but only noradrenaline restored mean arterial pressure. Noradrenaline improved RV contractility, as judged from the RV end-systolic pressure-volume relationship, probably because it increased the RV perfusion. Thus, noradrenaline in combination with volume loading may be the treatment of choice to improve RV performance in porcine septic shock associated with pulmonary hypertension.

Animals↗
PubMed1986

CT and nuclear medicine imaging in vertebral metastases.

Three cases are presented to illustrate the value of CT in elucidating the diagnosis in cancer patients presenting with complaints that are clinically highly suspicious for osseous metastases, where isotope bone imaging and conventional radiography failed to confirm the clinician's suspicion.

Aged↗