The prevalence of autoimmune disease in patients with esophageal achalasia.

Achalasia is a rare disease of the esophagus that has an unknown etiology. Genetic, infectious, and autoimmune mechanisms have each been proposed. Autoimmune diseases often occur in association with one another, either within a single individual or in a family. There have been separate case reports of patients with both achalasia and one or more autoimmune diseases, but no study has yet determined the prevalence of autoimmune diseases in the achalasia population. This paper aims to compare the prevalence of autoimmune disease in patients with esophageal achalasia to the general population. We retrospectively reviewed the charts of 193 achalasia patients who received treatment at Toronto's University Health Network between January 2000 and May 2010 to identify other autoimmune diseases and a number of control conditions. We determined the general population prevalence of autoimmune diseases from published epidemiological studies. The achalasia sample was, on average, 10-15 years older and had slightly more men than the control populations. Compared to the general population, patients with achalasia were 5.4 times more likely to have type I diabetes mellitus (95% confidence interval [CI] 1.5-19), 8.5 times as likely to have hypothyroidism (95% CI 5.0-14), 37 times as likely to have Sjögren's syndrome (95% CI 1.9-205), 43 times as likely to have systemic lupus erythematosus (95% CI 12-154), and 259 times as likely to have uveitis (95% CI 13-1438). Overall, patients with achalasia were 3.6 times more likely to suffer from any autoimmune condition (95% CI 2.5-5.3). Our findings are consistent with the impression that achalasia's etiology has an autoimmune component. Further research is needed to more conclusively define achalasia as an autoimmune disease.

Diagnostic accuracy of the Abbott ID NOW SARS-CoV-2 rapid test for the triage of acute medical admissions.

BACKGROUND: Decisions to isolate patients at risk of having coronavirus disease 2019 (COVID-19) in the emergency department (ED) must be rapid and accurate to ensure prompt treatment and maintain patient flow whilst minimising nosocomial spread. Reverse transcription polymerase chain reaction (RT-PCR) assays are too slow to achieve this, and near-patient testing is being used increasingly to facilitate triage. The ID NOW severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) assay is an isothermal nucleic acid amplification near-patient test which targets the RNA-dependent RNA-polymerase gene. AIM: To assess the diagnostic performance of ID NOW as a COVID-19 triage tool for medical admissions from the ED of a large acute hospital. METHODS: All adult acute medical admissions from the ED between 31st March and 31st July 2021 with valid ID NOW and RT-PCR results were included. The diagnostic accuracy of ID NOW [sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV)] was calculated against the laboratory reference standard. Discrepant results were explored further using cycle threshold values and clinical data. FINDINGS: Two percent (124/6050) of medical admissions were SARS-CoV-2 positive on RT-PCR. Compared with PCR, ID NOW had sensitivity and specificity of 83.1% [95% confidence interval (CI) 75.4-88.7] and 99.5% (95% CI 99.3-99.6), respectively. PPV and NPV were 76.9% (95% CI 69.0-83.2) and 99.6% (95% CI 99.5-99.8), respectively. The median time from arrival in the ED to ID NOW result was 59 min. CONCLUSION: ID NOW provides a rapid and reliable adjunct for the safe triage of patients with COVID-19, and can work effectively when integrated into an ED triage algorithm.

Behavioral repertoire of the Brazilian spiny-rats, Trinomys setosus and Clyomys laticeps: different levels of sociality.

Behavior is a useful trait for comparative studies that provide the comprehension of phylogenetic relationships among species. Here, we present a description of two spiny-rats species' behavioral repertoire, Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). The affiliative and agonistic behavioral patterns were sampled during a three-year study of captive populations of wild animals. Observational data were collected in two phases under different arrangements of individuals in groups. We also compare the behavioral traits of T. setosus and C. laticeps with the known behavioral patterns of Trinomys yonenagae. We add categories to the previous descriptions of T. setosus and a standard ethogram for C. laticeps. Trinomys setosus showed a visual and vocal display we called foot-trembling, which was not described in this form and function for other species studied until now. We discuss the differences in their sociality levels and similarities and differences among behavior patterns and repertoires.

Behavioral repertoire of the Brazilian spiny-rats, Trinomys setosus and Clyomys laticeps: different levels of sociality / Repertório comportamental dos ratos-espinhos brasileiros, Trinomys setosus e Clyomys laticeps: diferentes níveis de socialidade

Abstract Behavior is a useful trait for comparative studies that provide the comprehension of phylogenetic relationships among species. Here, we present a description of two spiny-rats species' behavioral repertoire, Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). The affiliative and agonistic behavioral patterns were sampled during a three-year study of captive populations of wild animals. Observational data were collected in two phases under different arrangements of individuals in groups. We also compare the behavioral traits of T. setosus and C. laticeps with the known behavioral patterns of Trinomys yonenagae. We add categories to the previous descriptions of T. setosus and a standard ethogram for C. laticeps. Trinomys setosus showed a visual and vocal display we called foot-trembling, which was not described in this form and function for other species studied until now. We discuss the differences in their sociality levels and similarities and differences among behavior patterns and repertoires.

Resumo O comportamento é uma característica útil para estudos comparativos que fornecem a compreensão das relações filogenéticas entre as espécies. Apresentamos aqui uma descrição do repertório comportamental de duas espécies de ratos-de-espinho Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). Os padrões comportamentais afiliativos e agonísticos foram amostrados durante um estudo de três anos em populações de animais silvestres em cativeiro. Os dados foram coletados em duas fases sob diferentes arranjos de indivíduos em grupos sociais. Comparamos as características comportamentais de T. setosus e C. laticeps com as da espécie mais conhecida, T. yonenagae. Adicionamos categorias às descrições anteriores de T. setosus, e um etograma padrão para C. laticeps. Trinomys setosus mostrou uma exibição visual e vocal que chamamos de saltitar, que não foi descrito nesta forma e função para outras espécies do gênero estudado até agora. Discutimos diferenças nos níveis de socialidade e similaridades e diferenças entre os padrões comportamentais e repertórios.

Behavioral repertoire of the Brazilian spiny-rats, Trinomys setosus and Clyomys laticeps: different levels of sociality / Repertório comportamental dos ratos espinhos brasileiros, Trinomys setosus e Clyomys laticeps: diferentes níveis de socialidade

Behavior is a useful trait for comparative studies that provide the comprehension of phylogenetic relationships among species. Here, we present a description of two spiny-rats species' behavioral repertoire, Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). The affiliative and agonistic behavioral patterns were sampled during a three-year study of captive populations of wild animals. Observational data were collected in two phases under different arrangements of individuals in groups. We also compare the behavioral traits of T. setosus and C. laticeps with the known behavioral patterns of Trinomys yonenagae. We add categories to the previous descriptions of T. setosus and a standard ethogram for C. laticeps. Trinomys setosus showed a visual and vocal display we called foot-trembling, which was not described in this form and function for other species studied until now. We discuss the differences in their sociality levels and similarities and differences among behavior patterns and repertoires.

O comportamento é uma característica útil para estudos comparativos que fornecem a compreensão das relações filogenéticas entre as espécies. Apresentamos aqui uma descrição do repertório comportamental de duas espécies de ratos-de-espinho Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). Os padrões comportamentais afiliativos e agonísticos foram amostrados durante um estudo de três anos em populações de animais silvestres em cativeiro. Os dados foram coletados em duas fases sob diferentes arranjos de indivíduos em grupos sociais. Comparamos as características comportamentais de T. setosus e C. laticeps com as da espécie mais conhecida, T. yonenagae. Adicionamos categorias às descrições anteriores de T. setosus, e um etograma padrão para C. laticeps. Trinomys setosus mostrou uma exibição visual e vocal que chamamos de saltitar, que não foi descrito nesta forma e função para outras espécies do gênero estudado até agora. Discutimos diferenças nos níveis de socialidade e similaridades e diferenças entre os padrões comportamentais e repertórios.

Behavioral repertoire of the Brazilian spiny-rats, Trinomys setosus and Clyomys laticeps: different levels of sociality

Abstract Behavior is a useful trait for comparative studies that provide the comprehension of phylogenetic relationships among species. Here, we present a description of two spiny-rats species behavioral repertoire, Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). The affiliative and agonistic behavioral patterns were sampled during a three-year study of captive populations of wild animals. Observational data were collected in two phases under different arrangements of individuals in groups. We also compare the behavioral traits of T. setosus and C. laticeps with the known behavioral patterns of Trinomys yonenagae. We add categories to the previous descriptions of T. setosus and a standard ethogram for C. laticeps. Trinomys setosus showed a visual and vocal display we called foot-trembling, which was not described in this form and function for other species studied until now. We discuss the differences in their sociality levels and similarities and differences among behavior patterns and repertoires.

Resumo O comportamento é uma característica útil para estudos comparativos que fornecem a compreensão das relações filogenéticas entre as espécies. Apresentamos aqui uma descrição do repertório comportamental de duas espécies de ratos-de-espinho Clyomys laticeps and Trinomys setosus (Rodentia: Echimyidae). Os padrões comportamentais afiliativos e agonísticos foram amostrados durante um estudo de três anos em populações de animais silvestres em cativeiro. Os dados foram coletados em duas fases sob diferentes arranjos de indivíduos em grupos sociais. Comparamos as características comportamentais de T. setosus e C. laticeps com as da espécie mais conhecida, T. yonenagae. Adicionamos categorias às descrições anteriores de T. setosus, e um etograma padrão para C. laticeps. Trinomys setosus mostrou uma exibição visual e vocal que chamamos de saltitar, que não foi descrito nesta forma e função para outras espécies do gênero estudado até agora. Discutimos diferenças nos níveis de socialidade e similaridades e diferenças entre os padrões comportamentais e repertórios.

Mechanisms of exercise limitation in hypertrophic cardiomyopathy.

To assess the relation of exercise capacity to indexes of systolic and diastolic function in hypertrophic cardiomyopathy, 81 patients underwent two-dimensional echocardiography, technetium-99m equilibrium radionuclide angiography acquired in list mode and maximal, symptom-limited, treadmill exercise testing with measurement of maximal oxygen consumption (VO2 max). VO2 max for the group was 13.9 to 49.3 (mean 25.4) ml/min per kg. Thirty-six patients (44%) achieved less than or equal to 70% of age-predicted VO2 max. Patients with such a degree of limitation were more likely to be in New York Heart Association functional class II or III (23 of 36 vs. 14 of 45; p = 0.005); there was no such relation between VO2 and the incidence and magnitude of rest left ventricular outflow tract pressure gradient greater than 30 mm Hg (11 of 36 vs. 11 of 45; p = NS and 58 +/- 24 vs. 65 +/- 19 mm Hg; p = NS). In the 22 patients with a left ventricular outflow tract gradient, the ratios of peak ejection to peak filling rate and of atrial contribution to left atrial dimension were related to percent of the age-predicted VO2 max (r = 0.49, p = 0.02 and r = 0.54, p less than 0.02). These ratios reflect impaired left ventricular systolic performance and atrial systolic failure, respectively. Stepwise discriminant analysis revealed these two ratios to be the two strongest predictors (p = 0.0001) of patients with a left ventricular outflow tract gradient whose VO2 max was less than or equal to 70% of the age-predicted value (sensitivity 90%, specificity 100%).(ABSTRACT TRUNCATED AT 250 WORDS)

Structure-activity relationships of novel hematoregulatory peptides.

Hematopoiesis is a lifelong cell renewal process regulated by a family of lineage specific hematopoietic growth factors. Several hematopoietic growth factors such as G-CSF, GM-CSF, and M-CSF have been clinically evaluated for enhancement of host defense in normal and immunocompromised patients and for the treatment of infectious diseases. This paper reports the structure-activity relationships of low molecular weight hematoregulatory peptides based on a nonapeptide (1, SK&F 107647). Like the macromolecular growth factors, these peptides modulate host defense. A molecular target for this class of compounds has not yet been identified. However, the structure-activity relationships established by this study implicate a very specific molecular recognition event that is pivotal for the biological activities of 1 and its analogues.

Cationic technetium-99m complexes of N-substituted pyridoxal derivatives as renal function agents.

UNLABELLED: New cationic technetium-chelating agents containing a pyridinium group have been synthesized and evaluated as potential renal radiopharmaceuticals. METHODS: The pyridinium compounds used in the study are N-methyl pyridoxal chloride, N-ethyl pyridoxal chloride, N-propyl pyridoxal chloride, 1-methyl-3-hydroxy-4-formylpyridinium chloride, 1-methyl-2-formyl-3-hydroxypyridinium chloride and the Schiff's bases of N-methyl pyridoxal chloride with amino acid, amino acid ester and amino acid amide. Complexes of these chelating agents with 99mTc were prepared using a Na2S2O4 or a SnCl2 solution as a reducing agent. The purity of the 99mTc complexes was determined by paper electrophoresis in 0.1 M tris buffer. RESULTS: Electrophoresis indicates slightly positive-charged species. The log P values of these complexes showed a hydrophilic nature. Urinary excretion of the 99mTc N-alkylated pyridoxal derivatives, 99mTc-diethylenetriaminepentaacetic acid, 99mTc-mercaptoacetylglycylglycylglycine (MAG3) and 131I-O-iodohippurate were determined in mice and rats at different time intervals. In a rat model, the pyridoxal-derived 99mTc complexes are rapidly excreted in urine and provide clear renal scintigrams. Hepatobiliary excretion was negligible, reducing scan interference from the intestines. Total clearances were lower than that of 131I-hippurate and 99mTc-MAG3. CONCLUSIONS: The rate of urinary clearance of the new tracers was not significantly faster than 99mTc diethylenetriaminepentaacetic acid and the inhibitor N1-methylnicotinamide had only a minimal effect on the renal behavior. Though the new tracers have cationic properties, the pyridinium group did not contribute largely to the excretion of active transport.

Effect of angiotensin-converting enzyme inhibitor (enalapril or imidapril) on ventilation during exercise in patients with chronic heart failure secondary to idiopathic dilated cardiomyopathy.

Eighteen patients with heart failure were studied to clarify whether angiotensin-converting enzyme inhibitor treatment improves excess ventilation during exercise. Treatment with angiotensin-converting enzyme inhibitors had a beneficial effect on excess ventilation during exercise, without significant improvement in exercise capacity in patients with moderate congestive heart failure.

Clinical and electrocardiographic profiles producing exercise-induced U-wave inversion in patients with severe narrowing of the left anterior descending coronary artery.

To elucidate which clinical features produce U-wave inversion, 339 patients with severe narrowing of the left anterior descending artery were evaluated. In patients with anterior myocardial infarction, extensive coronary artery disease and protected left anterior descending arterial territory are essential in the development of U-wave inversion, whereas electrocardiographic changes at rest in addition to anterior lead ST depression, rather than coronary anatomy, are important in those without anterior myocardial infarction.

Delayed recovery of postexercise blood pressure in patients with chronic heart failure.

Thirty-four patients with idiopathic dilated and ischemic cardiomyopathy underwent a symptom-limited cardiopulmonary exercise testing to evaluate the significance of postexercise blood pressure (BP) response. The postexercise BP response was useful in assessing the impaired exercise capacity and increased sympathetic activity in patients with heart failure.

Diagnostic significance of an exercise-induced prominent U wave in acute myocardial infarction.

A prominent U wave induced by exercise testing in patients with anterior wall myocardial infarction is a highly specific but insensitive marker for the narrowing of the left circumflex or right coronary artery, although a U-wave increase alone with or without ST-segment depression may help better identify these coronary artery narrowings. In patients with inferior and/or posterior myocardial infarction, a prominent U wave is regarded as a simple electrocardiographic marker for inferior and/or posterior residual ischemia.

Effect of diltiazem on sympathetic hyperactivity in patients with vasospastic angina as assessed by spectral analysis of arterial pressure and heart rate variability.

The autonomic nervous system importantly regulates coronary arterial tone and vascular resistance. To evaluate a role of autonomic nervous activity and the effects of calcium antagonist in patients with vasospastic angina (VSA), 13 VSA patients with patent coronary arteries (58+/-8 years) and 8 normal subjects (58+/-12 years) were studied. Arterial pressure and electrocardiogram were continuously recorded with the patient in a supine position under controlled respiration (0.2 Hz). Low-frequency (LF) and high-frequency (HF) components of the beat-to-beat variabilities of systolic arterial pressure and RR interval were then estimated by autoregressive power spectral analysis. The LF power (normalized unit) of both systolic arterial pressure (0.53+/-0.17 vs 0.30+/-0.17, p < 0.01) and RR variabilities (0.51+/-0.20 vs 0.31+/-0.16, p < 0.05) in patients with VSA were greater than that in normal subjects. There was no significant difference in the HF power. Seven patients with VSA who were treated with diltiazem (60 to 200 mg/day) had normalized LF power (normalized unit) of both systolic arterial pressure (0.62+/-0.12 vs 0.33+/-0.16, p < 0.01) and RR variabilities (0.55+/-0.23 vs 0.36+/-0.14, p < 0.05), together with clinical improvement. An increased sympathetic vasomotor tone and cardiac sympathetic predominance may play an important role in patients with VSA. Diltiazem improves these sympathetic hyperactivities.

Regional thallium-201 washout and myocardial hypertrophy in hypertrophic cardiomyopathy and its relation to exertional chest pain.

The mechanism of exertional chest pain in hypertrophic cardiomyopathy is uncertain, but may relate to myocardial ischemia. To study the mechanism of exertional chest pain in hypertrophic cardiomyopathy, dipyridamole-stress thallium-201 single-photon emission computed tomography was performed in 82 consecutive patients, and the 3-hour washout of thallium in relation to the tomographic image, regional wall thickness on echocardiography, and other clinical findings was analyzed. There was a weak inverse correlation of regional washout and wall thickness in 298 analyzed quadrant areas (r = -0.29; p = 0.0001). Twenty-five patients (31%) had history of exertional chest pain, and showed a significantly lower total washout and greater maximal left ventricular wall thickness than did those without chest pain (32 +/- 10% vs 37 +/- 9% [p = 0.03], and 27 +/- 7 vs 23 +/- 7 mm [p = 0.03], respectively). Even in mildly and nonhypertrophied areas, patients with chest pain had a significantly lower regional washout than did those without pain (33 +/- 10% vs 38 +/- 9%; p = 0.02), despite similar left ventricular wall thickness (12 +/- 2 vs 11 +/- 3 mm; p = NS). Reduced washout was strongly associated with exertional chest pain and was observed in myocardial regions that had normal as well as increased thickness, which indicates that this abnormality of thallium kinetics is a function of the disease process and not the magnitude of left ventricular hypertrophy.

Congenital coronary arteriovenous fistula associated with dilated cardiomyopathy.

A 59-year-old housewife with heart failure was found to have dilated cardiomyopathy associated with bilateral coronary artery fistula to the pulmonary artery. Coexistence of coronary arteriovenous fistula and dilated cardiomyopathy has not been reported and seems to be a casual association.

Atherosclerotic aortic plaque detected by transesophageal echocardiography: its significance and limitation as a marker for coronary artery disease in the elderly.

OBJECTIVES: To elucidate whether atherosclerotic aortic plaque detected by transesophageal echocardiography can be a clinically useful marker for coronary artery disease in the elderly. BACKGROUND: Atherosclerotic aortic plaque detected by transesophageal echocardiography has been reported to be a marker for coronary artery disease. Its significance may be important particularly in the elderly population, although to our knowledge, there are no data yet available. METHODS: We performed transesophageal echocardiography on 84 patients who had previously undergone coronary arteriography. The criteria used to diagnose atherosclerotic plaque on transesophageal echocardiography were the presence of focally or linearly increased echodensity of the aortic intima with lumen irregularity and thickening or ulceration. RESULTS: Significant coronary artery disease (> or = 50% stenosis) was detected in at least one major coronary artery in 27 of the 84 patients. Aortic plaques were detected by transesophageal echocardiography in 25 of the 27 patients (93%) with coronary artery disease and in 30 of 57 patients (53%) without coronary disease (p<0.001). Among 24 patients 70 years or older, aortic plaques were present in 13 of 14 (93%) patients with coronary artery disease and 9 of 10 patients (90%) without coronary disease. Among 60 patients younger than 70 years, aortic plaques were present in 12 of 13 patients (92%) with coronary artery disease and 21 of 47 patients (45%) without coronary disease (p<0.01). The independent association between coronary artery disease and the presence of aortic plaque, age, gender, and other coronary risk factors was examined by multiple logistic regression analysis. In patients 70 years or older, the presence of aortic plaque failed to be a predictor of significant coronary artery disease, although it was indeed a strong predictor of coronary artery disease in patients younger than 70 years (p<0.05). CONCLUSIONS: In elderly patients, atherosclerotic aortic plaque detected by transesophageal echocardiography is not useful in predicting significant coronary artery disease. It is useful only in a relatively younger population.

Low dose dobutamine stress echocardiography predicts the improvement of left ventricular systolic function in dilated cardiomyopathy.

OBJECTIVE: To determine whether dobutamine stress echocardiography can predict the improvement of left ventricular systolic function in patients with dilated cardiomyopathy (DCM). METHODS: Myocardial contractile reserve, as assessed by dobutamine stress echocardiography, was determined in 18 patients with DCM (mean (SD) age 53 (13) years, left ventricular ejection fraction (LVEF) 28 (10)%) and compared with changes in LVEF during a follow up period of 15 (8) months. The LVEF and regional left ventricular wall motion score (0, normal to 4, dyskinesis) of 12 segments in short axis and four chamber views were analysed before and after dobutamine infusion (5-20 microg/kg/min). RESULTS: During a follow up period of 15 (8) months, a significant improvement in LVEF (> 20%) was found in seven patients but not in the remaining 11. Baseline haemodynamic findings were similar in both groups. Patients with an improvement in follow up LVEF showed a greater change in wall motion score from baseline during dobutamine infusion than patients with no improvement (at rest, 1.7 (0.4) v 1.9 (0.2), NS; dobutamine 10 microg/kg/min, 0.6 (0.4) v 1.2 (0.4), p < 0.05). The percentage change in LVEF during dobutamine infusion was also significantly greater in patients who showed improvement than in those who did not. The change in LVEF during the follow up period (follow up LVEF/baseline LVEF) correlated well with the change in LVEF during dobutamine stress (LVEF at rest/LVEF at dobutamine 10 microg/kg/min; r = 0.74, p < 0.001). CONCLUSIONS: Changes in left ventricular systolic performance during low dose dobutamine stress echocardiography are a useful marker to predict the outcome of left ventricular systolic function in patients with DCM.

Radioimmunoscintigraphy using technetium-99m-labeled parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen in athymic nude mice bearing tumor.

Biodistribution and imaging characteristics of Tc-99m-labeled parental mouse and mouse-human chimeric antibodies to carcinoembryonic antigen (CEA), designated F11-39 and ChF11-39, respectively, were evaluated in athymic nude mice bearing the human CEA-producing gastric carcinoma (MKN-45) xenografts. Group F monoclonal antibodies such as F11-39 and ChF11-39 have been found to recognize the protein epitopes present on the domain B3 of the CEA molecule and to discriminate CEA in tumor tissues from the CEA-related antigens. The Tc-99m labeling was performed by immediately mixing a reduced antibody by 2-mercaptoethanol with Tc-99m pertechnetate in the presence of stannous chloride. The labeling yields of the two antibodies were greater than 95% when estimated using gel chromatography. Although these Tc-99m-labeled antibodies were stable in neutral saline solution, Tc-99m from both labeled antibodies was associated with cysteine solution. Technetium-99m ChF11-39 was more susceptible to transchelation than was Tc-99m F11-39. The immunoreactivity of each Tc-99m-labeled antibody was confirmed using MKN-45 cell-binding assay. Biodistribution studies in tumor-bearing mice were performed at 1 h, 5 h, and 20 h after being given IV injections of 3.7 MBq of either Tc-99m F11-39 or Tc-99m ChF11-39. All tumor-to-organ uptake ratios increased with time for both Tc-99m-labeled antibodies. Imaging results also showed selective and progressive accumulation of both Tc-99m antibodies at the tumor site. Both these Tc-99m-labeled antibodies have proved to be good radiotracers giving satisfactory scintigrams of the CEA-producing tumor.

Tumor-specific accumulation of 125I-labeled mouse-human chimeric anti-CEA antibody in a xenografted human cancer model demonstrated by whole-body autoradiography and immunostaining.

Whole-body autoradiography (WBAR) was used to study the biodistribution of 125I-labeled mouse-human chimeric antibody (Ch F11-39) to carcinoembryonic antigen (CEA) in athymic nude mice bearing the CEA-producing MKN-45 human gastric carcinoma xenografts. Significantly high uptake of 125I-Ch F11-39 in the tumors obtained by tissue-counting technique was confirmed by WBAR of mice of 12, 24, 48, and 96 h postinjection of 125I-Ch F11-39. When compared with histochemical or immunohistochemical staining results of the tumor tissue sections, imaging profiles of 125I-Ch F11-39 obtained by WBARs were topographically correlated with histopathological findings of tissues and immunohistochemical localization of CEA in the tumor tissues, indicating that the accumulation of 125I-Ch F11-39 at the tumor site is based on its specificity for CEA. These results demonstrate that this chimeric antibody may serve as a potential useful diagnostic and/or therapeutic reagent for human CEA-producing cancers.