Dietary carbohydrate rather than protein intake drives colonic microbial fermentation during weight loss.

PURPOSE: High protein weight loss diets are effective in aiding body weight management. However, high protein and low carbohydrate intakes can alter colonic fermentation profiles in humans and may impact on colonic health. This study aims to identify the most important dietary contributors to colonic fermentation during diet-controlled weight loss. METHODS: Overweight or obese male volunteers (n = 18) consumed a body weight maintenance diet (fed at 1.5× basic metabolic rate, BMR) followed by three weight loss diets (fed at 1× BMR) for 10 days each in a cross-over design. Weight loss diets were designed as normal protein (NPWL, 15% of energy from protein, 55% from carbohydrate), normal protein enriched with free amino acids and moderate amounts of carbohydrate (NPAAWL, 15% of energy from protein, 15% from free AA, 40% from carbohydrate) or high protein containing moderate amounts of carbohydrate (HPWL, 30% of energy from protein, 40% from carbohydrate). Faecal samples collected at the end of each diet period were profiled for dietary metabolites using LC-MS/MS. RESULTS: This study shows that the NPWL diet only induced very minor changes in the faecal metabolome, whereas NPAAWL and HPWL diets decreased carbohydrate-related metabolites (butyrate, ferulic acid) and increased protein-related metabolites. Most faecal metabolites were correlated with dietary carbohydrate and not protein intake. CONCLUSION: This study demonstrates that dietary carbohydrate is the main driver of colonic fermentation in humans and that a balance between dietary carbohydrate and protein should be maintained when designing safe, effective and healthy weight loss diets.

Butyrate-producing bacteria as probiotic supplement: beneficial effects on metabolism and modulation of behaviour in an obesity mouse model.

Obesity is a risk factor for cardio-metabolic and neurological disease. The contribution of gut microbiota to derangements of the gut-brain axis in the context of obesity has been acknowledged, particularly through physiology modulation by short-chain fatty acids (SCFAs). Thus, probiotic interventions and administration of SCFAs have been employed with the purpose of alleviating symptoms in both metabolic and neurological disease. We investigated the effects of four butyrate-producing bacteria from the Lachnospiraceae family on the development of metabolic syndrome and behavioural alterations in a mouse model of diet-induced obesity. Male mice were fed either a high-fat diet (HFD) or an ingredient-matched control diet for 2 months, and bacteria cultures or culture medium were given by gavage to HFD-fed mice every second day. Mice were assessed through a battery of metabolic and behaviour tests, and fluxes through the gut barrier and blood-brain barrier were determined using Dextran-based tracers. One of the administered bacteria from the Coprococcus genus, which produces butyrate and formate, afforded some degree of protection against the development of obesity and its complications. Results from this study, however, are insufficient to support brain health benefits of the bacteria tested. None of the bacteria modulated permeability through the gut or blood-brain barriers. Our results suggest health benefits of a bacteria from Lachnospiraceae family, and encourage further exploration of its use as probiotic.

Molecular and organizational diversity intersect to generate functional synaptic heterogeneity within and between excitatory neuronal subtypes.

Synaptic heterogeneity is a hallmark of complex nervous systems that enables reliable and responsive communication in neural circuits. In this study, we investigated the contributions of voltage-gated calcium channels (VGCCs) to synaptic heterogeneity at two closely related Drosophila glutamatergic motor neurons, one low- and one high-Pr. We find that VGCC levels are highly predictive of heterogeneous release probability among individual active zones (AZs) of low- or high-Pr inputs, but not between neuronal subtypes. Underlying organizational differences in the AZ cytomatrix, VGCC composition, and a more compact arrangement of VGCCs alter the relationship between VGCC levels and Pr at AZs of low- vs. high -Pr inputs, explaining this apparent paradox. We further find that the CAST/ELKS AZ scaffolding protein Bruchpilot differentially regulates VGCC levels at low- and high-Pr AZs following acute glutamate receptor inhibition, indicating that synapse-specific organization also impacts adaptive plasticity. These findings reveal intersecting levels of molecular and spatial diversity with context-specific effects on heterogeneity in synaptic strength and plasticity.

Incidental non-secreting adrenal masses in cancer patients: intra-individual comparison of 18F-fluorodeoxyglucose positron emission tomography/computed tomography with computed tomography and shift magnetic resonance imaging.

The ability of integrated (18)F-fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) to distinguish between benign and malignant incidental non-secreting adrenal masses was evaluated in cancer patients. Results were compared with those of CT and shift magnetic resonance imaging (MRI). A total of 1832 cancer patients who had undergone FDG PET/CT scans were retrospectively evaluated. Visual interpretation, tumour maximum standardized uptake value (SUV(max)), liver SUV(max) and tumour/liver SUV(max) ratios were correlated with the findings of CT, shift MRI and final diagnosis (based on biopsy or clinical/radiological follow-up). A total of 109 adrenal masses were found: 49 were malignant and 60 were benign on final diagnosis. A tumour/liver SUV(max) ratio threshold of 1.0 was more accurate in differentiating the tumour type than tumour SUV(max) or visual interpretation alone. Diagnostic accuracy of CT and shift MRI (92 - 97%) was similar to that for FDG PET/CT (94 - 97%). In conclusion, FDG PET/CT accurately characterizes adrenal tumours, with excellent sensitivity and specificity. Use of 1.0 as the threshold for the tumour/liver SUV(max) ratio seems to be promising for distinguishing benign from malignant adrenal masses in cancer patients.

(99m)Tc-Fab' fragments (sulesomab) for imaging septically loosened total knee arthroplasty.

The diagnostic accuracy of infection scintigraphy with (99m)Tc-labelled monoclonal antibody Fab' fragments (sulesomab) was studied in patients with suspected total knee arthroplasty (TKA) infection. Images from 26 patients were evaluated by two independent readers and compared with a quantitative interpretation of time-activity courses. Microbiological examinations and joint aspiration results were used as reference standards. Histologically, aseptic TKA loosening occurred in two patients and severe, moderate or mild septic loosening in four, nine and 11 patients, respectively. Diagnostic accuracy for severe infection was 100% for both readers, whereas for moderate infection accuracy decreased by 12% and 12% for readers one and two, respectively. For mild infection a further decrease of approximately 61% and 52% occurred for readers one and two, respectively. Quantitative evaluation gave significantly better results over visual interpretation with a diagnostic accuracy of 100% for severe infection and decreased by only 10% and 15% in patients with moderate and mild infection, respectively. Quantitative evaluation of (99m)Tc-Fab' fragments is highly sensitive and specific for diagnostic imaging of infection in patients with septically-loosened TKA.

[Nuclear medical imaging in case of painful knee arthroplasty]. / Nuklearmedizinische Diagnostik bei schmerzhafter Knieprothese.

RATIONALE: The aim of the present study was to calculate the overall diagnostic accuracy of nuclear medical imaging in patients with painful knee arthroplasty. MATERIAL AND METHODS: This retrospective study of all patients (n=87) where a (99m)Tc-triple phase bone scintigraphy (TPBS; n=120) and (99m)Tc-anti-granulocyte scintigraphy (BW 250/183; n=20) for a painful knee arthroplasty was performed between 2003 and 2007. RESULTS: A total of 87 patients with 94 knee arthroplasties were examined to detect septic and aseptic loosening and to differentiate between them. The sensitivity, specificity, the positive and negative predictive value and accuracy of TPBS for the detection of septic knee arthroplasty loosening was 100%, 85%, 55%, 100%, 73% and for BW 250/183 was 91%, 66%, 76%, 85%, 80% for sepsis, respectively. A significant increase in diagnostic accuracy with 94%, 88%, 89%, 95% und 89% (p <0.001) could be achieved when both methods were used in combination. CONCLUSION: Both methods alone have high negative predictive values, but the combination of both is complementary and significantly increases the diagnostic accuracy and positive predictive value for final diagnosis of knee arthroplasty loosening.

Lactobacillus rhamnosus strain GG restores alkaline phosphatase activity in differentiating Caco-2 cells dosed with the potent mycotoxin deoxynivalenol.

Deoxynivalenol (DON) contamination of cereal crops occurs frequently, and may cause acute exposure at high levels or chronic more moderate exposure. DON has proven toxicity including restriction of enterocyte differentiation, which may play a part in DON induced gastroenteritis. The probiotic bacteria Lactobacillus rhamnosus strain GG (GG) can bind DON, and therefore potentially restrict bioavailability of this toxin. Binding efficacy is not significantly altered by heat treatment, and therefore this in vitro study evaluated whether heat inactivated GG could restore the differentiation process in Caco-2 cells, using alkaline phosphatase (ALP) activity as a marker of differentiation. DON (200ng/mL) caused a significant (p<0.001) 36% reduction in ALP activity (1598+/-137U/mg protein) compared to untreated cells (2502+/-80U/mg). A dose dependant restoration of ALP activity was observed where DON treated cells were co-incubated with heat inactivated GG (1719+/-84; 2007+/-142; 2272+/-160U/mg for GG at 1x10(4) (p>0.9), 1x10(7) (p<0.001), and 1x10(10)CFU/mL (p<0.001), respectively). Co-incubation of the non-binding strain, LC-705 (1x10(10)CFU/mL), with DON did not significantly restore the ALP (1841+/-97U/mg, p<0.077) compared to DON only treated cells. When viable GG were co-incubated with DON a similar restoration of ALP activity was observed as seen for heat inactivated GG. These combined data suggest that the major effect of GG on restoring ALP activity, and therefore Caco-2 cell differentiation, was due to specific binding of DON, with possibly a more minor role of non-specific bacterial interference.

Serious complications after radiosynoviorthesis. Survey on frequency and treatment modalities.

AIM: Radiosynoviorthesis using intraarticular injection of beta-emitting radiocolloids is increasingly performed throughout Europe in patients with inflammatory joint disease. It is a cost-effective and safe treatment, local complications are very rare with only eight cases mentioned in the literature so far. No recommendations for therapy of tissue necrosis, infection or thromboembolism after radiosynoviorthesis are available. METHODS: Using a standardized questionary, 260 nuclear medicine physicians and 20 medical liability insurances were asked for the kind and frequency of complications after radiosynoviorthesis between 1998 and 2003. The survey was terminated after nine months with a response of only 25.7%. RESULTS: A total of 53 severe complications were documented (28 necroses, 12 thromboses, 13 joint infections). Eight other complications were seen but difficult to correlate directly with radiosynoviorthesis. Tissue necroses from yttrium-90 were successfully treated by surgical excision and closure of the defect. Rhenium-186-induced ulcers healed by hyperbaric oxygen therapy in two cases. Lesions from erbium-169 showed restoration by conservative treatment. Thromboembolic events happened after radiosynoviorthesis in joints of the lower limb only, mostly treated by conventional anticoagulation. Intraarticular infections showed restoration after intraarticular antibiotics in the majority of cases. CONCLUSION: Severe complications after radiosynoviorthesis seem to be rare. However, because of the low return rate, a reliable frequency cannot be calculated. Nevertheless, important advices regarding treatment concepts can be taken from our data.

Improved treatment of medullary thyroid cancer in a nude mouse model by combined radioimmunochemotherapy: doxorubicin potentiates the therapeutic efficacy of radiolabeled antibodies in a radioresistant tumor type.

Whereas in advanced metastatic medullary thyroid cancer (MTC), a variety of chemotherapeutic regimens have achieved only limited success clinically, more recently, radioimmunotherapy (RIT) with 131I-labeled anti-carcinoembryonic antigen (CEA) monoclonal antibodies (MAbs) has shown promising results. The aims of this study were to compare, in an animal model, the therapeutic efficacy of RIT to clinically used "standard" chemotherapeutic regimens and to evaluate whether combination strategies of both modalities may be feasible and may help to improve therapeutic results in this rather radioresistant tumor type. Nude mice, bearing s.c. xenografts of the human MTC cell line, TT, were treated either with the 131I-labeled anti-CEA MAb, F023C5 IgG, or were administered chemotherapeutic regimens that had shown promising results in patients with metastatic MTC (doxorubicin and cisplatinum monotherapy, combinations of both agents, and a 5-fluorouracil/dacarbazine/streptozotocin scheme). Control groups were left untreated or were injected with an irrelevant radiolabeled antibody at equitoxic dose levels. The maximum tolerated dose (MTD) of each agent was determined. Combinations of chemotherapy and RIT were evaluated as well. Toxicity and tumor growth were monitored at weekly intervals. From the chemotherapeutic agents and schemes tested, doxorubicin monotherapy was the most effective; combination therapies did not result in an increased antitumor efficacy, but they did result in more severe toxicity. At equitoxic doses, no significant difference was found between the therapeutic efficacy of doxorubicin and that of RIT. Myelotoxicity was dose limiting with radiolabeled MAbs (MTD, 600 microCi), as well as with chemotherapeutic regimens containing alkylating agents (cisplatinum, dacarbazine, or streptozotocin). At its MTD (200 microg), doxorubicin caused only mild myelotoxicity, and despite signs of cardiac toxicity, gastrointestinal side effects were dose limiting. Accordingly, bone marrow transplantation (BMT) enabled dose intensification with RIT (MTD with BMT, 1100 microCi), which led to further increased antitumor efficacy, whereas BMT was unable to increase the MTD of doxorubicin. Due to the complementarity of toxic side effects but an anticipated synergism of antitumor efficacy, combinations of RIT with doxorubicin were tested. Administrations of 500 microCi of 131I-labeled anti-CEA and, 48 h later, 200 microg of doxorubicin (i.e., 83 and 100% of the respective single-agent MTDs), were the highest doses that did not result in an increased lethality; with bone marrow support, 1000 microCi of 131I-labeled anti-CEA could be combined with 200 microg of doxorubicin (i.e., 90 and 100% of the individual MTDs). Therapeutic results of this combined radioimmunochemotherapy were superior to equitoxic monotherapy with either agent, and indication for synergistic antitumor effects is given. At its respective MTD, radioimmunochemotherapy led to a 36% cure rate if it was given without bone marrow support and to a 85% permanent cure rate if it was given with bone marrow support. The animal model, as presented in this study, seems to be useful for the preclinical testing of therapeutic agents for the systemic treatment of MTC. At equitoxic doses, RIT with radiolabeled anti-CEA antibodies seems to be equally as effective as chemotherapy with doxorubicin. Combination of RIT and doxorubicin chemotherapy seems to have synergistic therapeutic efficacy, which may be due to a radiosensitizing effect of doxorubicin.

High-linear energy transfer (LET) alpha versus low-LET beta emitters in radioimmunotherapy of solid tumors: therapeutic efficacy and dose-limiting toxicity of 213Bi- versus 90Y-labeled CO17-1A Fab' fragments in a human colonic cancer model.

Recent studies suggest that radioimmunotherapy (RIT) with high-linear energy transfer (LET) radiation may have therapeutic advantages over conventional low-LET (e.g., beta-) emissions. Furthermore, fragments may be more effective in controlling tumor growth than complete IgG. However, to the best of our knowledge, no investigators have attempted a direct comparison of the therapeutic efficacy and toxicity of a systemic targeted therapeutic strategy, using high-LET alpha versus low-LET beta emitters in vivo. The aim of this study was, therefore, to assess the toxicity and antitumor efficacy of RIT with the alpha emitter 213Bi/213Po, as compared to the beta emitter 90Y, linked to a monovalent Fab' fragment in a human colonic cancer xenograft model in nude mice. Biodistribution studies of 213Bi- or 88Y-labeled benzyl-diethylene-triamine-pentaacetate-conjugated Fab' fragments of the murine monoclonal antibody CO17-1A were performed in nude mice bearing s.c. human colon cancer xenografts. 213Bi was readily obtained from an "in-house" 225Ac/213Bi generator. It decays by beta- and 440-keV gamma emission, with a t(1/2) of 45.6 min, as compared to the ultra-short-lived alpha emitter, 213Po (t(1/2) = 4.2 micros). For therapy, the mice were injected either with 213Bi- or 90Y-labeled CO17-1A Fab', whereas control groups were left untreated or were given a radiolabeled irrelevant control antibody. The maximum tolerated dose (MTD) of each agent was determined. The mice were treated with or without inhibition of the renal accretion of antibody fragments by D-lysine (T. M. Behr et al., Cancer Res., 55: 3825-3834, 1995), bone marrow transplantation, or combinations thereof. Myelotoxicity and potential second-organ toxicities, as well as tumor growth, were monitored at weekly intervals. Additionally, the therapeutic efficacy of both 213Bi- and 90Y-labeled CO17-1A Fab' was compared in a GW-39 model metastatic to the liver of nude mice. In accordance with kidney uptake values of as high as > or = 80% of the injected dose per gram, the kidney was the first dose-limiting organ using both 90Y- and 213Bi-labeled Fab' fragments. Application of D-lysine decreased the renal dose by >3-fold. Accordingly, myelotoxicity became dose limiting with both conjugates. By using lysine protection, the MTD of 90Y-Fab' was 250 microCi and the MTD of 213Bi-Fab' was 700 microCi, corresponding to blood doses of 5-8 Gy. Additional bone marrow transplantation allowed for an increase of the MTD of 90Y-Fab' to 400 microCi and for 213Bi-Fab' to 1100 microCi, respectively. At these very dose levels, no biochemical or histological evidence of renal damage was observed (kidney doses of <35 Gy). At equitoxic dosing, 213Bi-labeled Fab' fragments were significantly more effective than the respective 90Y-labeled conjugates. In the metastatic model, all untreated controls died from rapidly progressing hepatic metastases at 6-8 weeks after tumor inoculation, whereas a histologically confirmed cure was observed in 95% of those animals treated with 700 microCi of 213Bi-Fab' 10 days after model induction, which is in contrast to an only 20% cure rate in mice treated with 250 microCi of 90Y-Fab'. These data show that RIT with alpha emitters may be therapeutically more effective than conventional beta emitters. Surprisingly, maximum tolerated blood doses were, at 5-8 Gy, very similar between high-LET alpha and low-LET beta emitters. Due to its short physical half-life, 213Bi appears to be especially suitable for use in conjunction with fast-clearing fragments.

Cure of metastatic human colonic cancer in mice with radiolabeled monoclonal antibody fragments.

There is currently no method to cure patients with disseminated colorectal cancer, which is the third leading cancer killer in the Western World. This report shows that the GW-39 intrapulmonary micrometastatic human colonic cancer model in nude mice can be cured with radiolabeled antibodies against carcinoembryonic antigen, and that this approach of radioimmunotherapy is superior to conventional chemotherapy with 5-fluorouracil and leucovorin (5-FU/LV). Monovalent Fab fragments labeled with 131I are superior to intact IgG when survival was evaluated 3, 7, and 14 days after implantation, leading to cures in up to 90% of the mice. Histological results provide support for the differences in therapeutic efficacy observed. Microautoradiography was used to evaluate the intratumoral distribution of each form of antibody. The enhanced tumor control by Fab compared with IgG could be explained in part by the homogeneity of radioantibody distribution of Fab. Biodistribution analysis and initial dose rate calculations for all three forms of antibody also help explain the ability of 131I-labeled Fab to provide better tumor growth control than seen with 131I-labeled IgG. Thus, radioimmunotherapy may be a new modality to treat metastatic disease, particularly when using small antibody fragments.

Cholecystokinin-B/gastrin receptor binding peptides: preclinical development and evaluation of their diagnostic and therapeutic potential.

The high sensitivity of pentagastrin stimulation in detecting primary or metastatic medullary thyroid cancer (MTC) suggests widespread expression of the corresponding receptor type on human MTC. Indeed, autoradiographic studies demonstrated cholecystokinin (CCK)-B/gastrin receptors not only in >90% of MTCs but in a high percentage of small cell lung cancers and potentially a variety of gastrointestinal adenocarcinomas. In a pilot study, we have demonstrated the feasibility of radiolabeled gastrin-I to target CCK-B receptor-expressing tissues in vivo in animals and patients (T. M. Behr et al., Eur. J. Nucl. Med., 25: 424-430, 1998). The aim of the present study was to systematically optimize, in a preclinical model, suitable radioligands for targeting CCK-B receptors in vivo. For this purpose, a variety of CCK/gastrin-related peptides, all having in common the COOH-terminal CCK-receptor binding tetrapeptide sequence Trp-Met-Asp-PheNH2 or derivatives thereof, were studied. They were radioiodinated by the Iodogen or Bolton-Hunter procedures. The peptides tested were members of the gastrin- or cholecystokinin families or possessed characteristics of both, which differ by the intramolecular position of a tyrosyl moiety (occurring in native or sulfated form). Their stability and affinity were studied in vitro and in vivo; their biodistribution and therapeutic efficacy were tested in nude mice bearing s.c. human MTC xenografts. Diethylene-triamine-pentaacetate derivatives of suitable peptides were synthesized, evaluated, and labeled with (111)In. All members of the CCK or gastrin family were stable in serum (with t(1/2)s of several hours at 37 degrees C); nevertheless, the stability of those peptides was highest that bore the NH2-terminal pGlu residues (e.g., big gastrin, gastrin-I, caerulein, and others) or D-amino acids. In accordance to their comparably low affinity, nonsulfated members of the CCK family showed fairly low uptake in the tumor and other CCK-B receptor-expressing tissues (e.g., the stomach). Sulfated CCK derivatives performed significantly better but additionally displayed a high uptake in normal, CCK-A receptor-expressing tissues (such as the liver/gallbladder, pancreas, and bowel). Best tumor uptake and tumor:nontumor ratios were obtained with members of the gastrin family, probably because of their selectivity and affinity for the CCK-B receptor subtype. Pilot therapy experiments in MTC bearing animals showed significant antitumor efficacy as compared with untreated controls. (111)In-Labeled diethylene-triamine-pentaacetate derivatives of minigastrin showed excellent targeting of CCK-B receptor-expressing tissues in animals and a normal human volunteer. These data suggest that CCK/gastrin analogues may be a useful new class of receptor binding peptides for diagnosis and therapy of CCK-B receptor-expressing tumors, such as MTC or small cell lung cancer. Nonsulfated gastrin derivatives may be preferable because of their CCK-B receptor selectivity, and hence, lower accretion in normal CCK-A receptor-expressing organs. Further preclinical as well as clinical studies are ongoing.

Low- versus high-dose radioimmunotherapy with humanized anti-CD22 or chimeric anti-CD20 antibodies in a broad spectrum of B cell-associated malignancies.

Both CD22 and CD20 have been used successfully as target molecules for radioimmunotherapy (RAIT) of low-grade B cell non-Hodgkin's lymphoma. Because both CD20 and CD22 are highly expressed relatively early in the course of B cell maturation, and because its expression is maintained up to relatively mature stages, we studied the potential of the humanized anti-CD22 antibody, hLL2, as well as of the chimeric anti-CD20 (chCD20) antibody, rituximab (IDEC-C2B8), for low- or high-dose (myeloablative) RAIT of a broad range of B cell-associated hematological malignancies. A total of 10 patients with chemorefractory malignant neoplasms of B cell origin were studied with diagnostic (n = 5) and/or potentially therapeutic doses (n = 9) of hLL2 (n = 4; 0.5 mg/kg, 8-315 mCi of 131I) or chCD20 (n = 5; 2.5 mg/kg, 15-495 mCi of 131I). The diagnostic doses were given to establish the patients' eligibility for RAIT and to estimate the individual radiation dosimetry. One patient suffered of Waldenström's macroglobulinemia, eight patients had low- (n = 4), intermediate- (n = 2) or high- (n = 2) grade non-Hodgkin's lymphoma, and one patient had a chemorefractory acute lymphatic leukemia, after having failed five heterologous bone marrow or stem cell transplantations. Three of these 10 patients were scheduled for treatment with conventional (30-63 mCi, cumulated doses of up to 90 mCi of 131I) and 7 with potentially myeloablative (225-495 mCi of 131I) activities of 131I-labeled hLL2 or chCD20 (0.5 and 2.5 mg/kg, respectively); homologous (n = 6) or heterologous (n = 1) stem cell support was provided in these cases. Good tumor targeting was observed in all diagnostic as well as posttherapeutic scans of all patients. In myeloablative therapies, the therapeutic activities were calculated based on the diagnostic radiation dosimetry, aiming at lung and kidney doses < or = 20 Gy. Stem cells were reinfused when the whole-body activity retention fell below 20 mCi. In eight assessable patients, five had complete remissions, two experienced partial remissions (corresponding to an overall response rate of 87%), and one (low-dose) patient had progressive disease despite therapy. In the five assessable, actually stem-cell grafted patients, the complete response rate was 100%. Both CD20 and CD22 seem to be suitable target molecules for high-dose RAIT in a broad spectrum of hematological malignancies of B cell origin with a broad range of maturation stages (from acute lymphatic leukemia to Waldenström's macroglobulinemia). The better therapeutic outcome of patients undergoing high-dose, myeloablative RAIT favors this treatment concept over conventional, low-dose regimens.

Aflatoxin B1 binding by a mixture of Lactobacillus and Propionibacterium: in vitro versus ex vivo.

Aflatoxin B1 (AFB) is a well-known carcinogen and reducing its bioavailability is of great interest for human and animal health. Several probiotic bacteria are able to bind AFB1 in vitro, including Lactobacillus rhamnosus LC-705 and Propionibacterium freudenreichii subsp. shermanii JS. A mixture of these two probiotics is used by the food and feed industry as biopreservative (Bioprofit), making it a promising candidate for future applications. Consequently, this study aims to investigate the in vitro and ex vivo ability of this probiotic mixture to bind AFB1. For in vitro experiments, probiotic mixture was suspended in an AFB1 solution (5 microM), incubated for 1 to 30 min, centrifuged, and AFB1 residues were quantitated in supernatant and pellet. For ex vivo experiments, duodenal loops of chicks were ligated and injected with either AFB1 solution alone or probiotic mixture suspension and AFB1 solution. Lumen content was centrifuged and AFB1 was quantitated in supernatant and pellet. Additionally, AFB1 was extracted from duodenal tissue to calculate tissue uptake. In vitro, 57 to 66% of AFB1 was removed from the solution by the probiotic mixture, but only 38 to 47% could be extracted from the bacterial surface. In ex vivo experiments, only up to 25% of AFB1 was bound by bacteria, and tissue uptake of AFB1 was significantly reduced when probiotic bacteria were present in the duodenal loop. Furthermore, the effect of intestinal mucus on the bacterial binding ability was investigated in vitro and was found to significantly reduce AFB1 binding by the probiotic mixture. However, probiotic mixture could only retard but not prevent AFB1 absorption in duodenal loops. Further work needs to assess the potential of probiotics in different experimental setups.

Comparison of the pressor effect of tyramine after treatment with phenelzine and moclobemide in healthy male volunteers.

This study was conducted to establish the safety, tolerability, side effects, and pressor effects of tyramine on subjects treated with moclobemide, a short-acting reversible and preferential monoamine oxidase inhibitor, and to compare these responses with the responses of subjects treated with phenelzine. Twelve healthy male volunteers participated. An oral tyramine sensitivity test was performed on all subjects 24 hours before the start of a 28-day open-label treatment with phenelzine or moclobemide. A tyramine challenge was performed on day 28 on four subjects treated with phenelzine. The mean dose of oral tyramine required to increase systolic blood pressure by 30 mm Hg was 15 mg. The mean dose of tyramine that produced a clinical response (day 28) in subjects treated with moclobemide was 240 mg. No subject receiving moclobemide responded clinically on day 31 after receiving hourly doses of 20, 40, 80, 160, and 320 mg, respectively. These findings suggest that moclobemide may be used without stringent dietary precautions.

Clinical value of immunoscintigraphy in patients with fever of unknown origin.

UNLABELLED: The aim of our study was to evaluate the clinical value of immunoscintigraphy with the monoclonal antibody 99mTc-BW 250/183 in patients with fever of unknown origin (FUO). The antibody BW 250/183 is an immunoglobulin G1 subtype that binds to the antigen NCA-95, which is expressed on the cell membrane surface of granulocytes. METHODS: We studied 51 patients who were referred with the diagnosis of FUO. Thirty-five percent of the patients suffered from infection, 17% had autoimmune diseases, 14% had neoplasms and 8% had other diseases. The remaining 28% of the patients did not have a diagnosis. Planar imaging was performed in all patients, and 19 patients underwent SPECT. In our analysis, both cold and hot spots were considered diagnostic. RESULTS: Pyogenic infections were visualized correctly in 13 foci. The diagnosis of endocarditis (n = 4) could be determined only by SPECT. False-negative results were found in 4 patients and false-positive uptake was seen in 2 patients. No false-positive uptake or cold spots in the central bone marrow were found in patients with viral, granulomatous and autoimmune diseases or in those patients in whom no FUO cause was found in a 6-mo follow-up. In these patients, a negative scan did not change their diagnostic work-up. Cold spots in the central bone marrow were correctly interpreted in 5 of 6 patients. Sensitivity in detecting pyogenic foci was 73% and specificity was 97%. Positive and negative predictive values were 93% and 87%, respectively. Including areas of decreased uptake in the analysis, sensitivity for detecting an underlying inflammatory or malignant process for FUO was 81 % and specificity was 87%. Positive and negative predictive values were 81% and 87%, respectively. CONCLUSION: Immunoscintigraphy with 99mTc-BW 250/183 in patients with FUO has clinical potential for the diagnosis and exclusion of pyogenic causes of FUO. Metastatic malignant disease and high-grade spondylodiskitis could be diagnosed early in a diagnostic work-up by a characteristic cold spot pattern in the bone marrow. SPECT is indispensible for scintigraphic imaging of endocarditis.

Radiolabeled peptides for targeting cholecystokinin-B/gastrin receptor-expressing tumors.

UNLABELLED: The high sensitivity of pentagastrin stimulation in detecting primary or metastatic medullary thyroid cancer (MTC) suggests widespread expression of the corresponding receptor type on human MTC. Indeed, autoradiographic studies have demonstrated cholecystokinin (CCK)-B/gastrin receptors not only in more than 90% of MTCs but also in a high percentage of small cell lung cancers, some ovarian cancers, astrocytomas and potentially a variety of adenocarcinomas. The aim of this study was to systematically screen and optimize, in a preclinical model and a pilot clinical study, suitable radioligands for targeting CCK-B receptors in vivo. METHODS: A variety of CCK/gastrin-related peptides, all bearing the C-terminal CCK receptor-binding tetrapeptide sequence Trp-Met-Asp-PheNH2 or derivatives thereof, were studied. They were radioiodinated by the lodogen or Bolton-Hunter procedures. The peptides were members of the gastrin or CCK families, which differ by the intramolecular position of a tyrosyl moiety. Their stability and affinity were studied in vitro and in vivo; their biodistribution and therapeutic efficacy were tested in nude mice bearing subcutaneous human MTC xenografts. Diethylenetriamine pentaacetic acid (DTPA) derivatives of suitable peptides were synthesized successfully, and their preclinical and initial clinical evaluations were performed, labeled with 111In. RESULTS: All members of the CCK or gastrin families were stable in serum (with half-lives of several hours at 37 degrees C); nevertheless, the stability of those peptides bearing N-terminal pGlu residues or D-amino acids was significantly higher. In accordance with their comparably low affinity, nonsulfated members of the CCK family showed fairly low uptake in the tumor and other CCK-B receptor-expressing tissues. Sulfated CCK derivatives performed significantly better but also displayed a comparably high uptake in normal CCK-A receptor-expressing tissues. This effect was probably due to their similar affinity for both CCK-A and CCK-B receptors. Best tumor uptake and tumor-to-nontumor ratios were obtained with members of the gastrin family because of their selectivity and affinity for the CCK-B receptor subtype. Pilot therapy experiments in MTC-bearing animals showed significant antitumor efficacy compared with untreated controls. DTPA derivatives of minigastrin were successfully developed. In a pilot clinical study, radioiodinated and 111In-labeled derivatives showed excellent targeting of physiological CCK-B receptor-expressing organs, as well as all known tumor sites. CONCLUSION: CCK/gastrin analogs may be a useful new class of receptor-binding peptides for diagnosis and therapy of CCK-B receptor-expressing tumors, such as MTC or small cell lung cancer. Nonsulfated gastrin derivatives may be preferable because of their CCK-B receptor selectivity, hence lower accretion in normal CCK-A receptor-expressing organs.

Rapid imaging of experimental colitis with (99m)Tc-interleukin-8 in rabbits.

UNLABELLED: Radiolabeled autologous leukocytes (WBCs) are the gold standard for imaging inflammatory bowel disease (IBD). For the rapid and adequate management of patients with IBD, there is need for a new agent at least as good as radiolabeled WBCs, but easier to prepare and without its inherent risks. In this study, the potential of interleukin-8 (IL-8) labeled with (99m)Tc using hydrazinonicotinamide (HYNIC) to image IBD was investigated in a rabbit model of acute colitis and compared with that of (99m)Tc-HMPAO-labeled granulocytes. METHODS: In rabbits with chemically induced acute colitis, inflammatory lesions were scintigraphically visualized after injection of either IL-8 or purified granulocytes, both labeled with (99m)Tc. Gamma camera images were acquired at 2 min and at 1, 2, and 4 h after injection. Four hours after injection, the rabbits were killed, and the uptake of the radiolabel in the dissected tissues was determined. The dissected colon was imaged and the inflammatory lesions were scored macroscopically. For each affected colon segment, the colitis index (affected colon-to-normal colon uptake ratio, CI) was calculated and correlated with the macroscopically scored severity of inflammation. RESULTS: Both agents visualized the colitis within 1 h after injection. (99m)Tc-HYNIC-IL-8 images of the colonic abnormalities were more accurate and the intensity of uptake in the affected colon continuously increased until 4 h after injection, whereas no further increase 1 h after injection was noticed scintigraphically for (99m)Tc-HMPAO-granulocytes. The absolute uptake in the affected colon was much higher for IL-8 than for the radiolabeled granulocytes with the percentage injected dose per gram (%ID/g) 0.41 +/- 0.04 %ID/g and 0.09 +/- 0.05 4 %ID/g h after injection, respectively. With increasing severity, the CI at 4 h after injection for (99m)Tc-HYNIC-IL-8 was 4.4 +/- 0.6, 13.5 +/- 0.5, and 25.8 +/- 1.0; for granulocytes, the CI at 4 h after injection was 1.5 +/- 0.1, 3.4 +/- 0.2, and 6.4 +/- 0.5, respectively. The CI correlated with the severity of the inflammation (r = 0.95, P < 0.0001 for IL-8; r = 0.95, P < 0.0001 for granulocytes). CONCLUSION: Within 1 h after injection, visualization of the extent of colonic inflammation in vivo was possible with (99m)Tc-HYNIC-IL-8 and (99m)Tc-HMPAO-granulocytes. Within 2 h after injection, (99m)Tc-IL-8 allowed a good evaluation, and within 4 h after injection, a meticulous evaluation of the severity of IBD. Although (99m)Tc-HMPAO-granulocytes were able to delineate the extent of IBD within 2 h after injection, an accurate estimation of severity of inflammation was not possible. (99m)Tc-HYNIC-IL-8 is an inflammation-imaging agent that showed promising results in this study. (99m)Tc-IL-8 can be prepared off-the-shelf and yields excellent imaging with high target-to-background ratios.

(99m)Tc-interleukin-8 for imaging acute osteomyelitis.

UNLABELLED: Early and accurate diagnosis of osteomyelitis remains a clinical problem. Acute osteomyelitis often occurs in infants and most often is located in the long bones. Radiologic images show changes only in advanced stages of disease. Scintigraphic imaging with (99m)Tc-methylene diphosphonate (MDP), or bone scanning, is much more sensitive in detecting acute osteomyelitis but lacks specificity. We evaluated the performance of (99m)Tc-interleukin-8 (IL-8) in an experimental model of acute osteomyelitis. METHODS: Acute pyogenic osteomyelitis was induced in 10 rabbits by inserting sodium morrhuate and Staphylococcus aureus into the medullary cavity of the right femur. The cavity was closed with liquid cement. A sham operation was performed on the left femur. Routine radiographs were obtained just before scintigraphy. Ten days after surgery, the rabbits were divided into 2 groups of 5 animals, received an injection of either 18.5 MBq (111)In-granulocytes or 18.5 MBq (67)Ga-citrate, and were imaged both 24 h after injection and 48 h after injection. On day 12, the rabbits received either 18.5 MBq (99m)Tc-MDP or 18.5 MBq (99m)Tc-IL-8, and serial images were acquired at 0, 1, 2, 4, 8, 12, and 24 h after injection. Uptake in the infected femur was determined by drawing regions of interest. Ratios of infected femur (target) to sham-operated femur (background) (T/Bs) were calculated. After the final images were obtained, the rabbits were killed and the right femur was dissected and analyzed for microbiologic and histopathologic evidence of osteomyelitis. RESULTS: Acute osteomyelitis developed in 8 of 10 rabbits. All imaging agents correctly detected the acute osteomyelitis in these animals. The extent of infection was optimally visualized with (67)Ga-citrate and delayed bone scanning, whereas diaphyseal photopenia was noted with both (99m)Tc-IL-8 and (111)In-granulocytes. In 1 rabbit with osteomyelitis, imaging results were falsely negative with (111)In-granulocytes and falsely positive with (99m)Tc-MDP. Quantitative analysis of the images revealed that the uptake in the infected region was highest with (67)Ga-citrate (4.9 +/- 0.8 percentage injected dose [%ID]) and (99m)Tc-MDP (4.7 +/- 0.7 %ID), whereas the uptake in the infected area was significantly lower with (99m)Tc-IL-8 (2.2 +/- 0.2 %ID) and (111)In-granulocytes (0.8 +/- 0.2 %ID) (P < 0.0042). In contrast, the T/Bs were significantly higher for (99m)Tc-IL-8 (T/B, 6.2 +/- 0.3 at 4 h after injection) than for (67)Ga-citrate, (99m)Tc-MDP, and (111)In-granulocytes, which had ratios of 1.5 +/- 0.4, 1.9 +/- 0.2, and 1.4 +/- 0.1, respectively (P < 0.0001). Radiography correctly revealed acute osteomyelitis in only 2 of 8 rabbits. CONCLUSION: In this rabbit model of osteomyelitis, (99m)Tc-IL-8 clearly revealed the osteomyelitic lesion. Although the absolute uptake in the osteomyelitic area was significantly lower than that obtained with (99m)Tc-MDP and (67)Ga-citrate, the T/Bs were significantly higher for (99m)Tc-IL-8 because of fast background clearance. The ease of preparation, good image quality, and lower radiation burden suggest that (99m)Tc-IL-8 may be a suitable imaging agent for the scintigraphic evaluation of acute osteomyelitis.

Photopenia in chronic vertebral osteomyelitis with technetium-99m-antigranulocyte antibody (BW 250/183).

UNLABELLED: Photon-deficient areas in 99mTc/111 in white blood cell (WBC) images for diagnosing vertebral osteomyelitis have been published often. This study retrospectively evaluated whether the use of 99mTc-labeled monoclonal antigranulocyte antibodies (BW 250/183) is superior to WBC and whether it offers higher specificity. METHODS: The study included 81 patients (46 men, 35 women; mean age 55 +/- 2 yr; from 1989 to 1995) with clinically suspected vertebral osteomyelitis who underwent scintigraphic imaging after intravenous injection of 555 MBq 99mTc-labeled monoclonal antigranulocyte antibodies. Forty patients suffered from osteomyelitis (20 men, 20 women; mean age 56 +/- 6 yr), 6 patients had metastases, 28 patients had spondylosis and disk herniation and 5 patients vertebral compression fractures. Diagnosis was not histologically verified in 2 patients. Planar imaging was performed at 4 and 24 hr postinjection. Histology of osteomyelitis was available in 30 patients, clinical follow-up in 10 patients. Visual uptake scores and quantitative uptake scores of the suspected areas were calculated. The results were compared to a semiquantitative histological score (high, medium, low grade) as well as to the scintigraphic scores. RESULTS: Scintigraphy showed photopenia in all patients with histologically proven vertebral osteomyelitis, independent of the grade of infection. A quantitative evaluation of 4 and 24 hr postinjection demonstrated a 58% increase of the uptake score in cases of histologically proven high-grade infections. This increase was seen predominantly in the thoracic spine but not in lumbar spine. All nonosseous paravertebral abscesses (n = 2) showed positive images and an increasing uptake over 24 hr. CONCLUSION: Paravertebral soft tissue infections can be differentiated excellently, whereas vertebral osteomyelitis, vertebral tumors or fractures can be localized, but no differentiation is possible.