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Deep learning for automated interictal epileptiform discharge (IED) detection has been topical with many published papers in recent years. All existing works viewed EEG signals as time-series and developed specific models for IED classification; however, general time-series classification (TSC) methods were not considered. Moreover, none of these methods were evaluated on any public datasets, making direct comparisons challenging. This paper explored two state-of-the-art convolutional-based TSC algorithms, InceptionTime and Minirocket, on IED detection. We fine-tuned and cross-evaluated them on a public (Temple University Events - TUEV) and two private datasets and provided ready metrics for benchmarking future work. We observed that the optimal parameters correlated with the clinical duration of an IED and achieved the best area under precision-recall curve (AUPRC) of 0.98 and F1 of 0.80 on the private datasets, respectively. The AUPRC and F1 on the TUEV dataset were 0.99 and 0.97, respectively. While algorithms trained on the private sets maintained their performance when tested on the TUEV data, those trained on TUEV could not generalize well to the private data. These results emerge from differences in the class distributions across datasets and indicate a need for public datasets with a better diversity of IED waveforms, background activities and artifacts to facilitate standardization and benchmarking of algorithms.
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Epilepsia , Humanos , Epilepsia/diagnóstico , Cuero Cabelludo , Electroencefalografía/métodos , AlgoritmosRESUMEN
BACKGROUND: Abdominal pain is the most distressing symptom of chronic pancreatitis (CP), and current treatments show limited benefit. Pain phenotypes may be more useful than diagnostic categories when planning treatments, and the presence or absence of constant pain in CP may be a useful prognostic indicator. AIMS: This cross-sectional study examined dimensions of pain in CP, compared pain in CP with chronic primary pain (CPP), and assessed whether constant pain in CP is associated with poorer outcomes. METHODS: Patients with CP (N = 91) and CPP (N = 127) completed the Comprehensive Pancreatitis Assessment Tool. Differences in clinical characteristics and pain dimensions were assessed between a) CP and CPP and b) CP patients with constant versus intermittent pain. Latent class regression analysis was performed (N = 192) to group participants based on pain dimensions and clinical characteristics. RESULTS: Compared to CPP, CP patients had higher quality of life (p < 0.001), lower pain severity (p < 0.001), and were more likely to use strong opioids (p < 0.001). Within CP, constant pain was associated with a stronger response to pain triggers (p < 0.05), greater pain spread (p < 0.01), greater pain severity, more features of central sensitization, greater pain catastrophising, and lower quality of life compared to intermittent pain (all p values ≤ 0.001). Latent class regression analysis identified three groups, that mapped onto the following patient groups 1) combined CPP and CP-constant, 2) majority CPP, and 3) majority CP-intermittent. CONCLUSIONS: Within CP, constant pain may represent a pain phenotype that corresponds with poorer outcomes. CP patients with constant pain show similarities to some patients with CPP, potentially indicating shared mechanisms.
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Dolor Crónico , Pancreatitis Crónica , Dolor Abdominal/etiología , Dolor Crónico/complicaciones , Estudios Transversales , Humanos , Dimensión del Dolor/métodos , Pancreatitis Crónica/complicaciones , Calidad de VidaRESUMEN
BACKGROUND: The diagnostic significance of the atopy patch test for the management of dermatitis possibly triggered by aeroallergens is still controversial. However, sufficiently large studies with routinely tested standardized aeroallergen patch test preparations in dermatitis patients are lacking. OBJECTIVE: To evaluate the reaction frequency and the reaction profiles of 10 until mid-2015 commercially available, standardized aeroallergen patch test preparations of the 'Stallerpatch' test series (Stallergenes, Antony Cedex, France) in a large multicentre patient cohort. METHODS: A retrospective data analysis of patients with suspected aeroallergen-dependent eczematous skin lesions was performed, who were patch tested in 15 Information Network of Departments of Dermatology-associated clinics between 2000 and 2015. Patients were stratified according to their atopic dermatitis (AD) status. RESULTS: The study group included 3676 patients (median age 41 years, 34.8% males, 54.5% AD). The most common aeroallergens causing positive patch test reactions were Dermatophagoides pteronyssinus (19.6%), Dermatophagoides farinae (16.9%), birch (6.2%), timothy grass (6.0%), cat dander (5.4%), mugwort (4.9%) and dog dander (4.6%). Reactions to other pollen allergen preparations, that is 5 grasses (3.2%), cocksfoot (2.1%) and plantain (1.6%), were less common. Positive patch test reactions to aeroallergens were consistently more frequent in patients with AD. These patients showed proportionally less dubious, follicular, irritant and weak positive reactions. Independent of AD status, a patient history of past or present allergic rhinitis was associated with an increased chance of a positive aeroallergen patch test reaction to pollen allergens. CONCLUSION: The aeroallergen patch test is a useful add-on tool in clinical routine, especially in patients with AD and/or respiratory allergy. A patch test series comprising Dermatophagoides pteronyssinus, Dermatophagoides farinae, birch, timothy grass, cat dander and mugwort seems to be suitable. Controlled studies with specific provocation and elimination procedures are required to further evaluate the diagnostic significance of the proposed screening series.
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Alérgenos , Animales , Gatos , Perros , Femenino , Francia , Alemania/epidemiología , Humanos , Masculino , Pruebas del Parche , Estudios Retrospectivos , Suiza/epidemiologíaRESUMEN
PURPOSE: Recent studies show that mutations in the gene encoding 11-cis retinol dehydrogenase are associated with fundus albipunctatus. The authors wanted to investigate whether additional, more severe, mutations in the 11-cis retinol dehydrogenase gene might be responsible for more severe forms of hereditary retinal diseases. DESIGN: Case-control molecular genetics study. PARTICIPANTS AND CONTROLS: Two index patients, 7 relatives, and 50 control individuals. METHODS: The authors screened two index patients diagnosed with fundus albipunctatus for mutations in exons 2 to 5 and exon/intron boundaries of the 11-cis retinol dehydrogenase gene by direct sequencing. Control individuals were screened for the presence of the mutations using allele-specific oligonucleotide hybridization. MAIN OUTCOME MEASURES: Mutations in exons 2 to 5 and exon/intron boundaries of the 11-cis retinol dehydrogenase gene. RESULTS: In a compound heterozygote, two novel mutations were found: a 4 bp insertion in exon 2 and a missense mutation Cys267Trp in exon 5. In a second pedigree, a homozygous frameshift mutation in codon 43 (Arg42ct[1-bpdel]) was detected. In both families, the mutations segregate with the disease. The mutations were not found in 50 control individuals. CONCLUSIONS: On the basis of our observations, it is unlikely that mutations in the 11-cis retinol dehydrogenase gene are associated with other, possibly more severe, retinal pathologic conditions/dystrophies or syndromic diseases in which the retina is also affected.
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Oxidorreductasas de Alcohol/genética , Enfermedades Hereditarias del Ojo/genética , Fondo de Ojo , Mutación , Ceguera Nocturna/genética , Adulto , Secuencia de Bases , Estudios de Casos y Controles , Niño , Análisis Mutacional de ADN , Exones/genética , Femenino , Humanos , Datos de Secuencia Molecular , Ceguera Nocturna/enzimología , Hibridación de Ácido Nucleico , LinajeRESUMEN
To elucidate the possible role of 11-cis-retinol dehydrogenase in the visual cycle and/or 9-cis-retinoic acid biosynthesis, we generated mice carrying a targeted disruption of the 11-cis-retinol dehydrogenase gene. Homozygous 11-cis-retinol dehydrogenase mutants developed normally, including their retinas. There was no appreciable loss of photoreceptors. Recently, mutations in the 11-cis-retinol dehydrogenase gene in humans have been associated with fundus albipunctatus. In 11-cis-retinol dehydrogenase knockout mice, the appearance of the fundus was normal and punctata typical of this human hereditary ocular disease were not present. A second typical symptom associated with this disease is delayed dark adaptation. Homozygous 11-cis-retinol dehydrogenase mutants showed normal rod and cone responses. 11-cis-Retinol dehydrogenase knockout mice were capable of dark adaptation. At bleaching levels under which patients suffering from fundus albipunctatus could be detected unequivocally, 11-cis-retinol dehydrogenase knockout animals displayed normal dark adaptation kinetics. However, at high bleaching levels, delayed dark adaptation in 11-cis-retinol dehydrogenase knockout mice was noticed. Reduced 11-cis-retinol oxidation capacity resulted in 11-cis-retinol/13-cis-retinol and 11-cis-retinyl/13-cis-retinyl ester accumulation. Compared with wild-type mice, a large increase in the 11-cis-retinyl ester concentration was noticed in 11-cis-retinol dehydrogenase knockout mice. In the murine retinal pigment epithelium, there has to be an additional mechanism for the biosynthesis of 11-cis-retinal which partially compensates for the loss of the 11-cis-retinol dehydrogenase activity. 11-cis-Retinyl ester formation is an important part of this adaptation process. Functional consequences of the loss of 11-cis-retinol dehydrogenase activity illustrate important differences in the compensation mechanisms between mice and humans. We furthermore demonstrate that upon 11-cis-retinol accumulation, the 13-cis-retinol concentration also increases. This retinoid is inapplicable to the visual processes, and we therefore speculate that it could be an important catabolic metabolite and its biosynthesis could be part of a process involved in regulating 11-cis-retinol concentrations within the retinal pigment epithelium of 11-cis-retinol dehydrogenase knockout mice.
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Oxidorreductasas de Alcohol/metabolismo , Retinoides/metabolismo , Oxidorreductasas de Alcohol/genética , Animales , Eliminación de Gen , Regulación Enzimológica de la Expresión Génica , Humanos , Ratones , Ratones Noqueados , Visión OcularRESUMEN
In many experimental biological situations, chelating agents like EGTA (ethylene glycol-bis-(beta-amino-ethyl ether) N,N,N',N'-tetra-acetic acid) are commonly used to control or suppress the concentration of divalent ions like Ca2+. The evaluation of liquid junction potentials in electrophysiological measurements, and particularly in patch-clamp situations, requires information about the ions within the solution. Where there is a significant concentration of EGTA present, it is necessary to know the values of the relative mobility of at least the most predominant ionic species of EGTA in order to complete these calculations. EGTA, with four negative charges with different pKas, can therefore exist as four differently charged ions in solution (EGTA-, EGTA2-, EGTA3- and EGTA4-) or as uncharged, although between pH 5.5 and 8 it is almost exclusively EGTA2-. We have measured limiting equivalent conductivities of the most common ionic forms of EGTA (EGTA2- and EGTA3-) encountered at physiological pHs. These were 35.9 +/- 0.7 and 56 +/- 2.5 S cm2 equiv(-1) respectively. Their mobilities relative to K+ were 0.24 +/- 0.01 for EGTA2- and 0.25 +/- 0.01 for EGTA3-. Thus for typical electrophysiological solutions, the contribution of EGTA to the liquid junction potential should be small (e.g. approximately 0.4 mV).
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Ácido Egtácico/química , Electrofisiología/métodos , Aniones , Cloruro de Calcio , Quelantes/química , Conductividad Eléctrica , Concentración de Iones de Hidrógeno , Cinética , Técnicas de Placa-Clamp , SolucionesRESUMEN
We recently cloned the murine 11-cis retinol dehydrogenase gene. A second gene, the murine GCN5L1 gene, was found to be situated upstream of the murine 11-cis retinol dehydrogenase gene. We have isolated and sequenced the complete coding sequence of the murine GCN5L1 gene. The distance between the 3'-end of the murine GCN5L1 gene and the 5'-end of the 11-cis retinol dehydrogenase gene is only 776 nt. The murine GCNSL1 gene consists of four exons encompassing approximately 3.5 kb of genomic DNA. Intron/exon splice sites conform to the GT/AG rule. The open reading frame consists of 375 nucleotides encoding a 14 kDa protein. The murine GCN5L1, like the human GCN5L1 protein, displays weak homology (27%) to yeast GCN5. The distance between the murine, human and bovine GCN5L1 and 11-cis retinol dehydrogenase genes appeared to be conserved.
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Proteínas del Tejido Nervioso , Transactivadores/genética , Oxidorreductasas de Alcohol/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bovinos , Clonación Molecular , ADN Complementario , Ligamiento Genético , Humanos , Ratones , Proteínas Mitocondriales , Datos de Secuencia Molecular , Homología de Secuencia de AminoácidoAsunto(s)
Bradiquinina/análogos & derivados , Compuestos de Organotecnecio/síntesis química , Compuestos de Organotecnecio/farmacología , Receptores de Bradiquinina/análisis , Secuencia de Aminoácidos , Animales , Bradiquinina/antagonistas & inhibidores , Bradiquinina/síntesis química , Bradiquinina/metabolismo , Bradiquinina/farmacología , Quelantes/síntesis química , Quelantes/metabolismo , Quelantes/farmacología , Etilaminas/síntesis química , Etilaminas/metabolismo , Etilaminas/farmacología , Cobayas , Marcaje Isotópico/métodos , Datos de Secuencia Molecular , Compuestos de Organotecnecio/metabolismo , Cintigrafía , Receptor de Bradiquinina B2 , Receptores de Bradiquinina/metabolismo , Distribución TisularRESUMEN
The present study describes the synthesis of a [99mTc]diaminomercapto(thio)ether (DAMTE-derivative) as a first compound of a new class of 99mTc-complexes which is tubular excreted. 10-Benzoyl-8-keto-7-aza-2-amino-4,10-dithia-decanoic acid (CO2-DAMTE 3) was synthesized by the reaction of succinimidyl-S-benzoyl-thioglycolate and (S)-2-aminoethyl-L-cysteine. The respective technetium complex, 99mTc-CO2-DAMTE was obtained in radiochemical yields of about 70% using stannous chloride as reducing agent. Hydrolysis of the protecting group was performed either prior to the complexation of pertechnetate ("cold kit") or during the labelling reaction ("hot kit"). Organ distribution was determined in Wistar rats. Within 24 h 40% of the activity were excreted into the feces and 43% into the urine, whereas 10% were retained in the kidneys. In contrast, a first human study showed a very fast renal elimination of 99mTc-CO2-DAMTE, a low liver uptake (< 10%) and no retention in the kidneys. The renal clearance of approx. 240 mL/min/1.73 m2 in addition to the protein binding of > 95% suggests an effective tubular excretion of the compound.
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Cisteína/análogos & derivados , Riñón/diagnóstico por imagen , Compuestos de Organotecnecio/síntesis química , Animales , Proteínas Sanguíneas/metabolismo , Cisteína/síntesis química , Cisteína/metabolismo , Cisteína/farmacocinética , Humanos , Espectroscopía de Resonancia Magnética , Masculino , Compuestos de Organotecnecio/metabolismo , Compuestos de Organotecnecio/farmacocinética , Cintigrafía , Ratas , Ratas Wistar , Distribución TisularRESUMEN
Lately, the specific binding of appropriate monoclonal antibodies to human granulocytes has been used for the scintigraphic detection of inflammatory foci. Using the antibody BW 250/183 we studied the underlying binding kinetics. As an important requirement for a specific cell binding it has been shown that the labelling procedure does not change the immunoreactivity of the antibody. An affinity constant of 2 x 10(9) l/mol has been calculated from binding studies. Usually, 0.25-1.0 mg of the 99mTc-labelled antibody are applied per patient. In the present study an equilibrium in blood appeared quickly after intravenous application; at steady state about one fourth of the activity was cell-bound. The rest of the activity circulated in the plasma in the form of labelled IgG and was able to react directly with those granulocytes which were already accumulated in the inflamed area. Even a drastic reduction of the applied protein mass did not change this equilibrium. The law of mass action seems not to be directly applicable to this problem. Interferences with components of the plasma can be excluded as explanation for this behaviour. After application of in-vitro labelled granulocytes from which unbound antibodies were removed completely by washing, an identical steady state was observed within 10 min after injection; however, in this situation the intravasal residence time of activity increased distinctly.
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Anticuerpos Monoclonales/metabolismo , Granulocitos/metabolismo , Humanos , Radioisótopos de Indio , Inflamación/diagnóstico por imagen , Marcaje Isotópico , Radioinmunodetección , TecnecioRESUMEN
The study was designed to find out whether the commercially available antibodies BMA 130 c, BMA 120, V 9, KL 1, B 72.3 TAG, HEA 125 and Ber-EP 4 would be of help in distinguishing carcinomas from a mesothelial process (mesothelioma/pleuritis) in pleural effusion specimens routinely processed by the cytoblock method. All of the 20 carcinomas included in the study but also 19 of the 20 mesotheliomas expressed cytokeratin (KL 1), whereas vimentin expression was found in 7 of the 20 carcinomas and 19 of the 20 mesotheliomas. 19 of the 20 carcinomas reacted with the epithelial markers B 72.3 and HEA 125, and 18 of them with Ber-EP 4. In contrast, only a few of the 20 mesotheliomas showed a weak reaction to these markers (1 with HEA 125, 2 with B 72.3, and 3 with Ber-EP 4). BMA-130 c was detected in 10/20 carcinomas but in none of the mesotheliomas. BMA-120 was observed in the effusions from 17/20 mesotheliomas and in cover cells which had undergone reactive changes, but also in 2 cases of ovarian carcinoma. The results show that reaction to the "epithelial markers" B 72.3, HEA 125 and Ber-EP 4 is strongly indicative of carcinoma and not of mesothelioma, whereas a positive reaction with the antibody BMA-120 in the absence of reaction to the epithelial markers makes a mesothelial process very likely. However, immunocytochemical distinction cannot be made as yet between mesothelioma cells and pleuritic cells. If simultaneous positivity for BMA-120 and an "epithelial marker" in a pleural effusion is observed the primary tumor could be an ovarian carcinoma.
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Carcinoma/diagnóstico , Mesotelioma/diagnóstico , Derrame Pleural Maligno/patología , Anticuerpos Monoclonales , Biomarcadores de Tumor , Carcinoma/química , Carcinoma/patología , Diagnóstico Diferencial , Humanos , Inmunohistoquímica , Mesotelioma/química , Mesotelioma/patologíaRESUMEN
A two phase radioimmunotherapy based on bispecific MAbs in which one arm recognises a tumour antigen and the other a radiolabelled chelate, may prove more effective in the treatment of carcinomas than currently available immunotherapies. To establish this system we first showed that penetration into human carcinoma xenografts as well as long term retention of intact MAb outside the carcinoma cells can be obtained. Epitope saturation was not obtained however, despite the large MAb doses injected i.v. for 10 days. We then generated hybridomas producing high avidity anti-metal chelate MAbs (anti-DTPA-Y). These hybridomas were fused with hybridomas producing MAbs against CEA or GIT-mucin, and stable bispecific MAb producing quadromas were obtained. For the anti-GIT-mucin x anti-chelate MAb a purification procedure based on double anti-idiotype affinity chromatography was shown to result in greater than 95% pure bispecific immunoreactive MAb. Comparative in vivo stability studies profiled DTPA-Y as the chelate of choice for in vivo application.
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Anticuerpos Monoclonales/uso terapéutico , Neoplasias del Colon/radioterapia , Neoplasias Pancreáticas/radioterapia , Ácido Pentético/uso terapéutico , Radioisótopos de Itrio/uso terapéutico , Animales , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/metabolismo , Neoplasias del Colon/metabolismo , Humanos , Inyecciones Intravenosas , Ratones , Ratones Desnudos , Neoplasias Pancreáticas/metabolismo , Ácido Pentético/metabolismo , Células Tumorales Cultivadas , Radioisótopos de Itrio/metabolismoAsunto(s)
Anticuerpos Monoclonales/uso terapéutico , Neoplasias Experimentales/radioterapia , Animales , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Antígeno Carcinoembrionario/inmunología , Humanos , Ratones , Neoplasias Experimentales/inmunología , Neoplasias Experimentales/metabolismo , Ácido Pentético/uso terapéutico , Radioterapia/métodos , Receptores de Droga/biosíntesis , Receptores de Droga/inmunología , Radioisótopos de Itrio/uso terapéuticoRESUMEN
We have found that a maleimidobenzoyl spacer attached to OH-4' of the rhodosamine moiety of rhodosaminylanthracyclinone-type anthracyclines is most suitable for the attachment of these drugs to carriers, providing important advantages: The spacer is selectively and most readily introduced into the rhodosamine moiety of the drugs, is stable enough for proper handling of the derivatives, and can easily be attached to thiol groups of carrier systems such as reduced monoclonal antibodies. The anthracyclines can be liberated from the conjugates by mere hydrolysis, requiring neither hydrolytic enzymes nor acidic pH. Liberation of the drugs can, moreover, be affected by the presence of the appropriate substituents Z on the phenylene ring of the spacer, thus allowing slowed or enhanced liberation of the cytostatically active drug. The corresponding p-maleimidobenzoyl derivatives of beta-rhodomycin I, N,N-dimethyldaunorubicin, and rodorubicin have been attached to thiol groups of the hinge region of reduced monoclonal antibody BW 494/32, directed against a pancreatic cancer associated glycoprotein antigen, resulting in MoAb BW 494/32 conjugates, carrying 4.8-6.8 mol of cytotoxic residues/mol of MoAb. Rodorubicin was similarly attached to MoAb BW 575/931/2, directed against a small cell lung cancer associated antigen and to MoAb BW 431/26, recognizing an epitope detectable on carcinoembryonic antigen. The results provide evidence that the newly developed method of coupling of anthracyclines to the hinge region of monoclonal antibodies may be of broader use.
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Antraciclinas , Antibióticos Antineoplásicos/química , Anticuerpos Monoclonales , Hexosaminas/química , Antibióticos Antineoplásicos/síntesis química , Complejo Antígeno-Anticuerpo/análisis , Antígenos de Neoplasias/análisis , Antígenos de Neoplasias/inmunología , Sitios de Unión , Estabilidad de Medicamentos , Hexosaminas/síntesis química , Humanos , Indicadores y Reactivos , Cinética , Espectroscopía de Resonancia Magnética , Estructura Molecular , Unión Proteica , Relación Estructura-ActividadRESUMEN
Immunoscintigraphy is a new method for in vivo diagnosis of diseases using monoclonal antibodies. Emphasis is placed on diagnosis of malignant tumors although the range of application includes a number of non-malignant diseases. To date, no European country has issued clear guidelines on the testing and registration of those monoclonal antibodies labelled with a radionuclide and used for diagnostic. This involves the risk of overregulation which would considerably reduce the applicability of the method. This holds particularly true since the complications initially anticipated with the use of such compounds did not occur. The conduct of immunoscintigraphy has evolved during the last few years. For reasons of applicability, but also and mainly for reasons of radiation hygiene, I-131 and finally also In-111 were abandoned as labelling nuclides and replaced by Tc-99m. The protein amount involved was reduced. Some false estimations, which were due to particularities or artifacts of the iodinated antibodies used at the beginning, had to be corrected: the representation of the liver in a scintigram is part of the physiological distribution of antibodies; and fragments of antibodies normally do not present the anticipated kinetic advantages. The clinical results obtained with colon carcinomas show that not only recurrencies and metastases, but also primary tumors can be detected with equally high sensitivity. In contrast, radioimmunotherapy does not yet seem as successful, at least against solid tumors.
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Anticuerpos Monoclonales , Neoplasias del Colon/diagnóstico por imagen , Animales , Neoplasias del Colon/secundario , Evaluación de Medicamentos , Política de Salud , Humanos , Técnicas In Vitro , Países Bajos , Cintigrafía , Sistema de RegistrosRESUMEN
The routine application of immunoscintigraphy for the detection of colorectal carcinomas is now possible thanks to the development of the BW 431/31-F(ab')2-DTPA-In-111 or the BW 431/26-Tc-99m kits. The quick tumor localization (6 hours p.i.), the specificity and sensitivity (approximately equal to 90%) as well as the lack of side reactions argue for the quality of the reagents. The change from I-131 labelled murine monoclonal antibodies (MAbs) to In-111 or Tc-99m immunoconjugates in kit form resulted in a reduction of radiation dose for the patient down to 20% (In-111) or to 5% (Tc-99m) of the dose applied using I-131 labelled MAbs. The BW 250/183-Tc-99m conjugate suited for the immunoscintigraphic detection of inflammatory processes by in vivo labelling of granulocytes possesses the same favourable characteristics. The specific tumor immunotherapy of pancreatic carcinoma using MAb BW 494 points to interesting effects which have to be statistically confirmed in future clinical trials.
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Anticuerpos Monoclonales/uso terapéutico , Neoplasias Colorrectales/diagnóstico por imagen , Inmunoterapia/métodos , Neoplasias Pancreáticas/terapia , Especificidad de Anticuerpos , Antígeno Carcinoembrionario/inmunología , Granulocitos , Humanos , Radioisótopos de Indio , Ácido Pentético , Tecnecio , Tomografía Computarizada de EmisiónRESUMEN
Starting from the phenomenon that the amount of circulating CEA in patients' sera did not significantly influence immunoscintigraphic visualization of CEA expressing tumors, we built up an in vitro model to explain this phenomenon. Blocking experiments in this model system showed that the CEA specific MAbs BW 431/26 and BW 431/31 could not be inhibited in their binding to cell associated CEA, if they were preincubated with a 20 molar excess of serum CEA. In contrast, the CEA-NCA cross reactive MAbs could be inhibited in their binding to tumor associated CEA under identical conditions. These data combined with western blotting analysis of patients' sera and affinity constant determinations argue that conformational changes in serum CEA cause a decreased affinity of the CEA specific MAbs to serum CEA allowing a preferential binding to tumor associated CEA.
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Antígenos de Neoplasias , Antígeno Carcinoembrionario/análisis , Moléculas de Adhesión Celular , Neoplasias/diagnóstico por imagen , Anticuerpos Monoclonales , Biomarcadores de Tumor/análisis , Antígeno Carcinoembrionario/inmunología , Epítopos/inmunología , Glicoproteínas/inmunología , Humanos , Técnicas In Vitro , Neoplasias/metabolismo , CintigrafíaRESUMEN
When used for immunoscintigraphic detection of malignant tumours, monoclonal antibodies are frequently labelled with indium-111. This study investigated whether antibody properties are affected by DTPA, the chelating agent with which the antibody has to be bound before labelling with indium-111. Chromatography, cell binding assays and animal studies indicated marked changes in the chemical, immunological and biological properties of the F(ab')2 antibody fragment 431/31 at DTPA:F(ab')2 ratios greater than 1. It is concluded that, in order to avoid lasting effects on the normal biokinetic behaviour of this antibody, the DTPA:F(ab')2 ratio for the antibody should not exceed 1.
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Anticuerpos Monoclonales , Radioisótopos de Indio , Marcaje Isotópico/métodos , Ácido Pentético , Fragmentos Fab de Inmunoglobulinas , Fragmentos de InmunoglobulinasRESUMEN
The effects of cryonecrosis in rat kidney after single and repeated local freezing were studied by morphological and cell kinetic methods. Shortly after single and repeated cryolesions a well-demarcated coagulation necrosis developed which was replaced by granulation tissue. 4 weeks after the second freezing only a small fibrous scar was visible. Cell analysis revealed no significant differences between single and repeated cryolesions. Autoradiographically, however, it was shown that the labelling index of fibroblasts in the granulation tissue was higher after repeated than after single cryolesions. The proliferation maxima of epithelial cells were delayed for 24 h. After 4 weeks the cell proliferation again had reached normal values. Hardly any differences between wound healing after single and after repeated cryolesion were found. Thus, repeated is advisable and no complications should be expected.