[Receptor scintigraphy using 111In-pentetreotide in endocrine gastroenteropancreatic tumors]

Receptor scintigraphy with 111In-pentetreotide is a complementary imaging technique with a sensitivity of 88% for the localization of the primary tumor and its metastases in patients presenting with the clinical and biochemical symptoms of an endocrine tumor of the gastrointestinal tract or the pancreas. As a whole-body scintigraphic technique it covers all body regions and is also able to reveal small tumors which can only be detected with difficulty or not at all by the usual imaging methods. In 104 patients with GEP tumors or after operative removal of such tumors, receptor scintigraphy proved to be superior to ultrasound and computed tomography in 34%, equal in 52% and inferior in 14% of the cases.

Preoperative localization of gastrointestinal endocrine tumors using somatostatin-receptor scintigraphy

OBJECTIVE

The purpose of this study was to determine the value of somatostatin-receptor scintigraphy (SRS) in the preoperative localization of gastrointestinal endocrine tumors. The authors report their preliminary experiences with this new technique as compared to conventional imaging studies like computed tomography (CT) and ultrasonography (US).

SUMMARY BACKGROUND DATA

Most endocrine tumors possess high-affinity somatostatin-receptors. Using the stable, 111Indium labelled somatostatin analogue pentatreotid, which binds to these receptors, it is possible to detect somatostatin-receptor-positive tumors scintigraphically.

METHODS

In nine patients with various gastrointestinal endocrine tumors, SRS, CT, and US were performed before surgical exploration. The preoperative imaging studies and intraoperative ultrasound (IOUS) were then compared to findings on surgical exploration.

RESULTS

Twelve primary tumors were found in 8 patients at surgical exploration. These primary tumors were correctly identified with SRS in five patients, with US in four patients, and with CT in three patients. In one patient with the Zollinger-Ellison syndrome, scintigraphy suggested a tumor in the area of the hepatoduodenal ligament, while CT and US had negative results. The underlying gastrinoma could not be identified despite extensive surgical exploration. Scintigraphy, CT, and US showed comparable results in the detection of metastases in four patients.

CONCLUSIONS

The data from this small series suggest that SRS is helpful in the preoperative localization of gastrointestinal endocrine tumors.

Somatostatin analog sandostatin and inhibition of tumor growth in patients with metastatic endocrine gastroenteropancreatic tumors

A prospective study was performed to determine the efficacy of octreotide (Sandostatin; SMS 201-995) 200 micrograms tid in controlling tumor growth. The study included 21 patients with metastasized endocrine GEP tumors: 6 gastrinomas, 8 carcinoid syndromes, 7 nonfunctioning tumors. Treatment was performed for 3 to 59 months (median 15 months). Evaluation of the response to octreotide was facilitated in 12 patients by a pretreatment observation period of 3 to 47 months (median 17 months) during which the natural growth behavior was determined. Based on the presence or absence of a control period prior to treatment, 5 patients were considered to be responders, 7 as questionable responders (no pretreatment phase available), and 9 as nonresponders. None of the 21 patients had documented shrinkage of the tumor mass. The most favorable response was tumor standstill. In all but one responder an escape to an initially favorable response occurred after 6 to 28 months (median 14 months). Proved inhibition of growth was paralleled by a reduction of serum and urine hormone parameters, whereas unaltered progression of tumor growth was observed also in the presence of hormone suppression. Tumor growth and hormone release was inhibited in the absence and presence of somatostatin receptors on the tumor. It is concluded that octreotide exerts a limited effect on metastatic GEP tumor growth. The evaluation of a response to octreotide is facilitated by an observation period prior to the drug that provides information on growth characteristics of the tumor. The presence of octreotide receptors does not predict the success of therapy.

Bronchoalveolar lavage. Quantitation of intraalveolar fluid?

A precise calculation of the amount of intraalveolar fluid is the basis of a quantitative analysis of intraalveolar compounds. Different approaches have been made to cover this important problem. Here, we report a comparative study with five markers: 99mTc-DTPA, 51Cr-EDTA, inulin, urea, and methylene blue in animal experiments as well as in human experiments. The marker substances were added to the lavage fluid, and the "dilution" of the markers, i.e., the alveolar fluid, was calculated. The results showed that in animals with healthy lungs the tracer methods are able to calculate amounts of intraalveolar fluid that are comparable to morphologic findings. In animals as well as in humans, methylene blue and inulin were shown to be useless in determining alveolar fluid volume compared with the tracer methods. In humans, the calculations with the urea method and with Tc-DTPA were in the same magnitude, but there was no individual correlation. We conclude that, at present, the methods to quantitate alveolar fluid volume lack precision and add nothing to a deeper understanding of alveolar biology.

Effects of phorbol myristate and ionomycin on in vitro growth of aged Peyer's patch T and B cells

The proliferative responses of Peyer's patch (PP) T cells from aged BALB/c mice to concanavalin A (Con A) are considerably reduced, as compared to those of the young (P < 0.001). This reduced reactivity of aged T cells could be partly, but not entirely, corrected by interleukin 2 (IL-2) (P < 0.001). PP T cells from aged mice responded synergistically to a protein kinase C (PKC) activator, phorbol myristate acetate (PHA), plus a calcium ionophore, ionomycin, at much lower concentrations than to Con A (P < 0.001); however, the maximal proliferative response still remained nearly at 8/10th of the young (P < 0.01) and higher levels of PMA (but not of ionomycin) were required (P < 0.001). Addition of IL-2 restored the diminished response to the levels of the young T cells (P < 0.05), but that of Con A did not (P > 0.05). The proliferative responses of PP B cells to lipopolysaccharide (LPS) do not differ from those of the young (P > 0.05), but the spontaneous proliferation of aged (unstimulated) B cells is enhanced nearly twofold versus that of the young (P < 0.001). Like the PP T cells, PP B cells from aged mice also responded synergistically to PMA plus ionomycin but to a lesser degree than those of the young under the same stimulation (P < 0.01). Their maximal proliferation required higher levels of PMA, but not of ionomycin and was also diminished (P < 0.01), compared to that of the young. B cell stimulatory co-factors, IL-4 and IL-6, failed to affect the response of aged and young B cells to PMA plus ionomycin (P > 0.05), whereas LPS remediates the reduced response of aged B cells to PMA plus ionomycin. Thus, T and B cells from senescent PP demonstrate an impaired proliferative responsiveness via the Ca-dependent PKC pathway. A T cell mitogen and B cell stimulatory cytokines did not alter this activation pathway, once optimally stimulated. Whereas, T cell stimulatory cytokine IL-2 and B cell mitogen LPS could restore the age-associated decline of the corresponding lymphocyte subsets, T and B cells, in activation of the Ca-dependent pathway. The altered transmembrane signal transduction appears to be intrinsically defective in these aged PP T and B cells.

Hemophan versus hemophan--a philippic against the suggestion of constant membrane quality

All statements referring to biocompatibility of dialyzers depend on the suggestion of a constant and reproducible structure of the investigated membrane material. The data presented here strike this concepts in case of hemophane. Two commercially available hemophane dialyzers, the GF MC 120 (Gambro) and the MO 450 (SMAD) membranes, were compared. Significant differences could be seen in the induction of leukopenia and leukocyte sequestration reaction within patients lungs, but also in capacity to influence granulocyte oxidative metabolism and release of granular enzymes. According to these data it seems questionable whether hemophane is a membrane material with constant structure and quality normally expected for products bearing trade names. Excluding other differences (like surface-area or sterilization method) variable amounts of DEAE substituents and/or an inconstant distribution of the DEAE groups within the membranes may be the most possible reason responsible for the differences found. The study underlines the urgent need of an exact physico-chemical characterization of dialyzer membranes and is therefore a challenge for free publication of such basic data by the producers.

IL4, IL5 and IL6-mediated regulation of immunoglobulin (Ig) heavy chain class switching and Ig production by gut-associated lymphoid tissue (GALT) B cells from athymic nude (nu/nu) mice

Gut mucosal immunoglobulin (Ig) isotype expression and secretion are known to be regulated by B cell-stimulatory factors (BSF), lymphokines or cytokines from T and non-B cells. The class and amount of Ig secreted appear to depend on the presence of a combination of these factors. The effects of IL-4 and IL-5 on Ig class switching by gut mucosal B cells remain controversial. To shed further light on this issue, young (1-2 months old) athymic nu/nu murine GALT B cells were chosen, because the possibility of in vivo effects of T cells on B cells (in particular at the levels of transcription and translation without changes in surface Ig phenotype expression) cannot be excluded. The results are summarized below. IL-4, IL-5 and IL-6 alone or in combination do not act as IgA heavy chain switch cofactors, but IL-5 and IL-6 do act at least as B cell terminal differentiation factors for any isotype-specific gut-associated lymphoid tissue (GALT) (mesenteric lymph node) B cells in the presence or absence of LPS. The BSF have augmenting effects on class-specific Ig production by GALT sIgM-bearing B cells, when these are treated with the BSF alone. IL-4 alone or in combination with other BSF prevents LPS-stimulated IgM production. BSF without LPS do not evoke production of significant amounts of IgG and IgA by high density (HD) and low density (LD) sIgM-bearing B cells; IgM is synthesized only in small amounts of LD sIgM-bearing B cells in the presence of IL-5 and/or IL-6. There is no difference in the responsiveness of GALT and spleen sIgM-bearing B cells to the BSF.

Nontraumatic, acute neonatal paraplegia

Nontraumatic, acute neonatal paraplegia with associated lower limb vascular phenomena is a relatively rare condition. Three such cases are reported. The paralysis is primarily motor with minimal neurologic recovery. Contractures and bizarre deformities develop at an early stage and necessitate repeated orthopaedic intervention. The most likely etiology appears to be a vascular insult to the spinal cord.

Early developmental profile of ornithine decarboxylase in the frog, Microhyla ornata and its regulation by polyamines

Ornithine decarboxylase (ODC) activity and polyamine levels were measured during early development of the frog, Microhyla ornata. ODC activity was found to be high and it showed three major peaks during the first 60 hr of development. Putrescine and spermidine levels increased gradually during the above period with little change in spermine. Treatment of developing embryos with exogenous putrescine and spermidine prevented the normal increase in ODC activity. Spermine did not have any significant effect. Addition of ornithine also prevented the increase in ODC activity. Experiment using exogenous ornithine and alpha-methylornithine revealed that formation of putrescine and/or spermidine from ornithine is necessary for the suppression of ODC to occur. Suppression of ODC takes place even if conversion of putrescine to spermidine is blocked, indicating that putrescine, independent of its conversion to spermidine, also plays a role in ODC regulation.

Assessment of ventricular function with first-pass radionuclide angiography using technetium 99m hexakis-2-methoxyisobutylisonitrile: a European multicentre study

In the context of a multicentre study on the use of technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-Sestamibi), we evaluated the accuracy of the ventricular function assessed at rest by means of first-pass radionuclide angiocardiography acquired during the injection of the tracer for myocardial perfusion scintigraphy. The results were compared with first-pass studies performed using reference tracers sodium pertechnetate Tc 99m or technetium 99m diethylene triamine penta-acetic acid or with gated radionuclide angiocardiography. A total of 66 patients of the 105 enrolled in the study could be evaluated. The comparison of the first-pass studies was possible in 33 subjects with regard to the left ventricular ejection fraction, yielding r = 0.909 (P less than 10(-6)), and in 22 cases with regard to the right ventricular ejection fraction, yielding r = 0.712 (P less than 0.001). The comparison between the first-pass study using 99mTc-Sestamibi and the equilibrium gated radionuclide angiocardiography was possible for the left ventricular ejection fraction in 26 cases, with r = 0.937 (P less than 10(-6)), and for the right ventricular ejection fraction in 15 subjects, with r = 0.783 (P less than 0.001). In conclusion, the assessment of ventricular function performed by acquiring a first-pass radionuclide angiocardiograph during the injection of 99mTc-Sestamibi for perfusion myocardial scintigraphy can be considered reliable and accurate, when compared with the usually employed techniques. This result confirms the feasibility of a combined evaluation of perfusion and function at rest and during stress testing, which represents one of the most interesting advantages offered by the use of 99mTc-Sestamibi.

Kinetics of pulmonary leukocyte sequestration in man during hemodialysis with different membrane-types

Although it has been suggested that pulmonary sequestration of leukocytes could account for membrane-dependent white blood cell depletion in HD, direct evidence in patients is still lacking. Therefore a study was initiated to test whether and how leukocytes distribute in the lung circulation during HD with different membranes. Thirteen patients suffering from chronic renal failure underwent lung scintigraphy during HD with cuprophane (n = 3), hemophane (n = 8) and polysulfone (n = 2) lowflux capillary dialyzers. Isolated autologous leukocytes were labelled with 99m-Technetium and reinfused before starting HD. Distribution of leukocyte related activity was registered by lung scintigraphy. In comparison to normal lung scintigraphy performed without HD, an impressive redistribution peak was demonstrated 10-20 min after the start of HD with cuprophane and also to a lesser extent with hemophane. When HD was performed with polysulfone the decrease in activity was delayed but no real redistribution was obtained. In accordance with other phenomena, such as peripheral leukopenia and changes in granulocyte oxidative metabolism, pulmonary sequestration of leukocytes takes place in man in the initial phase of HD and appears to be strongly dependent on the type of membrane.

[99mTc-2-methoxy-isobutyl-isonitrile in the diagnosis of coronary heart disease: results of a multicenter study]

A total of 226 patients was studied in a phase-III multicenter trial to compare the results of stress/rest 99mTc-MIBI with 201TI scintigraphy and/or coronary arteriography. The evaluation of planar and SPECT imaging was based on a semiquantitative visual scoring. A congruent diagnosis was generated from all planar 201TI and 99mTc-MIBI scintigrams performed in 36 patients. In 62 of 63 patients, SPECT-studies with 99mTc-MIBI and 201TI led to an identical diagnosis. In one patient a positive result was obtained with 201TI-SPECT whereas 99mTc-MIBI was negative. Segmental agreement for 1509 SPECT segments was 85.7%, for 554 planar segments it was 86.6%. In comparison to coronary arteriography, performed in 180 patients, the overall sensitivity for the correct diagnosis of coronary artery disease (CAD) was 86% for planar MIBI scintigraphy or 92% for MIBI-SPECT. Overall specificity was 100% for planar imaging and 57% for SPECT. The low specificity of MIBI-SPECT was probably due to high prevalence of CAD in this study population. In a subgroup of 43 patients, who underwent coronary angiography, identical results were found with 99mTc-MIBI and 201TI. Only one patient showed a positive scintigraphic result with both 99mTc-MIBI and 201TI without angiographically proven stenosis greater than 50% or prior myocardial infarction. Vessel sensitivities in stenosed coronary arteries (greater than 50% stenosis) were 54% for the LAD and 87% for the RCX/RCA areas with MIBI-SPECT, or 51% or 79% for planar scintigraphy, respectively. Vessel specificities for SPECT were 65% in the LAD or 52% in the RCX/RCA, or 90% or 83% in planar imaging.(ABSTRACT TRUNCATED AT 250 WORDS)

99mTc-2-Methoxy-lsobutyl-Isonitril in der Diagnostik der koronaren Herzkrankheit: Ergebnisse einer Multizenterstudie

A total of 226 patients was studied in a phase-Ill multicenter trial to compare the results of stress/rest 99mTc-MIBI with 201TI scintigraphy and/or coronary arteriography. The evaluation of planar and SPECT imaging was based on a semiquantitative visual scoring. A congruent diagnosis was generated from all planar 201TI and 99mTc-MIBI scintigrams performed in 36 patients. In 62 of 63 patients, SPECT-studies with 99mTc-MIBI and 201TI led to an identical diagnosis. In one patient a positive result was obtained with 201TI-SPECT whereas 99mTc-MIBI was negative. Segmental agreement for 1509 SPECT segments was 85.7%, for 554 planar segments it was 86.6%. In comparison to coronary arteriography, performed in 180 patients, the overall sensitivity for the correct diagnosis of coronary artery disease (CAD) was 86% for planar MIBI scintigraphy or 92% for MIBI-SPECT. Overall specificity was 100% for planar imaging and 57% for SPECT. The low specificity of MIBI-SPECT was probably due to high prevalence of CAD in this study population. In a subgroup of 43 patients, who underwent coronary angiography, identical results were found with 99mTc-MIBI and 201TI. Only one patient showed a positive scintigraphic result with both 99mTc-MIBI and 201TI without angiographically proven stenosis greater than 50% or prior myocardial infarction. Vessel sensitivities in stenosed coronary arteries (>50% stenosis) were 54% for the LAD and 87% for the RCX/RCA areas with MIBI-SPECT, or 51 % or 79% for planar scintigraphy, respectively. Vessel specificities for SPECT were 65% in the U\D or 52% in the RCX/RCA, or 90% or 83% in planar imaging. According to the results of this study, 99mTc-MIBI is of the same diagnostic value as 201TI in nuclear cardiology. Scintigraphy with both radiopharmaceuticals correlates well with the diagnosis of CAD. Therefore, 99mTc-MIBI might be an effective substitute for 201TI for myocardial perfusion scintigraphy.

[Effect of fenofibrate on fibrinogen concentration and blood viscosity. Consequences for myocardial microcirculation in coronary heart disease?]

The effect of fenofibrate (a clofibrate derivative) on fibrinogen concentration, blood viscosity and myocardial microcirculation was examined in 35 patients with coronary heart disease (n = 27) or hypertension (n = 8). After eight weeks' administration of 250 mg fenofibrate daily cholesterol and triglycerides levels decreased significantly, as did the fibrinogen concentration, from a mean of 300.7 +/- 75.1 mg/dl to 252.3 +/- 61.2 mg/dl (P less than 0.01). Plasma viscosity and erythrocyte aggregation were also significantly lowered (from 1.43 +/- 0.09 to 1.37 +/- 0.07 mPas and 15.0 +/- 3.1 to 13.5 +/- 2.2, respectively; P less than 0.01). In eight of twelve subjects selected from the whole group thallium myocardial scintigraphy demonstrated, after eight weeks of treatment with fenofibrate, a global (in two) or regional (in six) increase in blood flow. Reduction of fibrinogen concentration may in coronary heart disease achieve an improvement in myocardial microcirculation with decreased myocardial ischaemia.

Granulocyte-related bioincompatibility of hemodialysis: inhibition of oxidative metabolism, degranulation reaction, enzyme release and leukocyte sequestration in the lung

Hemodialysis (HD) induced contact of granulocytes with cuprophan and modified cuprophan, i.e. hemophan, membranes leads to over-stimulation of their oxidative metabolism. This is shown by the fact that after starting HD the peripheral granulocytes are less stimulable to chemiluminescence (CL) and peroxide production (cytochrome C reduction). Such alterations are likely to be connected with a granular staining loss, enzyme release and sequestration of granulocytes in the lung, which coincides with reported clinical features like dyspnoea and drop in arterial oxygen pressure. HD with polysulfone membranes causes a degranulation reaction too, but does not produce granulocyte inhibition and pulmonary sequestration of leukocytes, clearly indicating that these phenomena strongly depend on the different dialyzer membranes.

Imaging of inflammation with granulocytes labelled in vivo

We have looked for inflammatory lesions in 37 patients using granulocytes labelled in vivo. For the purpose of cell labelling we used a monoclonal murine antibody reacting with NCA and carcinoembryonic antigen (CEA) (BW 250/183) labelled with 99Tcm. All abscesses and other inflammatory lesions were visualized with excellent quality scintigrams between 2 and 6 h after the injection. As the antibody can be stored in a freeze-dried form and labelled at any time in any department of nuclear medicine with 99Tcm without cell separation being necessary, the method appears to be suitable even for use in acute diagnosis. No side effects have so far been found.

In vivo labelling of granulocytes with 99mTc anti-NCA monoclonal antibodies for imaging inflammation

We looked for inflammatory lesions in 45 patients using in vivo labelled granulocytes. For the purposes of cell labelling we used a murine, monoclonal antibody reacting with NCA and CEA (BW 250/183) (Bosslet et al. 1985) labelled with 99mTc-pertechnetate. All abscesses and other inflammatory lesions were visualized with excellent quality scintigrams between 2 and 6 h after the injection. As the antibody can be stored in a freeze-dried form and labelled at any time in any Department of Nuclear Medicine with 99mTc-pertechnetate, without cell isolation being necessary, the method appears to be suitable even for use in acute diagnosis. No side-effects have so far occurred, even in patients injected up to three times.

[99mTc tin colloid scintigraphy in the diagnosis of acute rejection reactions in kidney transplants]

Quantitative measurements of 99MTc-tin colloid uptake in renal transplants permits differentiation of acute rejection from other causes of deteriorating renal function, such as acute tubular necrosis, cyclosporin A nephrotoxicity or chronic rejection. 144 99mTc-tin colloid scintigrams were performed on 71 renal transplants; the results were compared with clinical, biochemical and histological findings. Sensitivity of colloid scintigraphy is 97.4% and specificity is 80%. Compared with other isotope methods, this has the advantage that it does not depend on comparison with repeated examinations.

Adenylate cyclase stimulation and [3H]thymidine incorporation in human thyroid tissues and thyrocyte cultures: the effect of IgG preparation from patients with different thyroid disorders

Primary cell cultures of normal and adenomatous human thyroid tissues were incubated with TSH or ammonium sulphate precipited IGG fractions (1 mg/ml) of sera from patients with different thyroid diseases (Graves' disease: active n = 7 in remission n = 12; thyroid autonomy n = 39; simple euthyroid goitre n = 15) and were compared to controls (n = 26). [3H]thymidine incorporation in primary thyrocyte cultures demonstrated a typical bell shape curve after incubation with EGF and TSH with a maximal effect at 10-100 microIU/ml. This effect, however, was inconsistent and positive only in 2 of 7 primary cultures. Only TSH positive cultures were used for IgG studies. 16-28% of IGG fractions from sera of thyroid patients caused high (more than X + 5 SD of controls) stimulation of [3H]thymidine incorporation. Dose response curves of IgG fractions of 19 additional patients (Graves' disease in remission n = 15; thyroid autonomy n = 4) showed an increase in [3H]thymidine incorporation at 0.1 mg protein/ml for 10 patients and at low concentrations of 10-5 mg/ml for 5 patients. There was a good correlation (r = 0.72) (P less than 0.0001) between positive findings in TSH-binding inhibition (TBII) and AC-stimulation (TSI) IGG fractions but none between stimulation of [3H]thymidine incorporation and any other thyroid specific immunoglobulin nor thyroid function nor any other available data. Immunoglobulins stimulating [3H]thymidine incorporation differ therefore from TBII and TSI. The growth effect of these immunoglobulins, however, has yet to be determined.