Clinical Profile of a New Monoclonal Antibody-Based Immunoassay for Tissue Polypeptide Antigen

Our preliminary evaluation of a new monoclonal antibody-based assay for tissue polypeptide antigen (TPA) has shown it to be clinically equivalent to the polyclonal antibody-based assay for TPA. The new assay (TPA-M) employs three monoclonal antibodies to epitopes on cytokeratins 8, 18 and 19. This multicenter, multinational study included 266 patients with newly diagnosed carcinomas of the lung, breast, large bowel and urinary bladder. TPA values from the two assays were compared with three other cytokeratin markers (TPS, CYFRA 21–1 and TPACyk) and with the established reference markers for these malignancies (CEA and NSE for lung, CA 15–3 for breast, CEA and CA 19–9 for colorectal tumors). Analysis of receiver operating characteristic (ROC) curves in lung, colorectal and bladder cancer showed similar sensitivities for the two assays, ranging from 50% to 80% with a specificity of 95%. In breast cancer all the markers studied showed poor sensitivity. However, TPA determination by either method could discriminate advanced stage (stages III and IV) from early stage disease (stages 0 to II). TPA showed similar discriminating ability in bladder cancer. On the basis of the results obtained in our patient series, it seems that of the cytokeratin markers studied, TPA and TPA-M are the most sensitive and offer a wide range of clinical applications.

Food increases the bioavailability of tolterodine but not effective exposure

The objective of this study was to investigate the influence of food on the pharmacokinetics of tolterodine, its active 5-hydroxymethyl metabolite (5-HM), and exposure to the active moiety (sum of unbound tolterodine + 5-HM) in healthy volunteers. Serum concentrations of tolterodine and 5-HM were measured for up to 12 hours after a single oral dose (2 mg) of tolterodine L-tartrate, administered either on an empty stomach or with a standardized medium-fat breakfast. All 23 subjects completing the study were classified as extensive metabolizers (phenotyped with debrisoquine). Pharmacokinetic data on tolterodine and the active moiety were evaluable for 22 subjects; all completing subjects were evaluable for 5-HM pharmacokinetics. Based on Cmax and AUC(infinity) ratios, relative bioavailability of tolterodine in the presence of food was 1.49 (90% confidence interval [CI], 1.35-1.71) and 1.53 (1.35-1.72), respectively. The pharmacokinetics of 5-HM and the active moiety were unaffected by food, as were the rates of drug absorption and terminal half-lives of tolterodine and 5-HM. Given that bioequivalence was observed for the active moiety underfed and fasting conditions, the authors concluded that coadministration of tolterodine with food is not expected to have any clinically relevant effects.

GM-CSF in chemotherapy-induced febrile neutropenia--a double-blind randomized study

Modern chemotherapy programmes render patients susceptible to bacterial and fungal infections, and the risk of developing febrile neutropenia after a chemotherapy course is in proportion to the severity and duration of the neutropenia thus caused. This double-blind randomized study presents details of 29 patients who developed febrile neutropenia an average of 10 days after their course of chemotherapy for different types and stages of malignancy. Fourteen received granulocyte/macrophage colony stimulating factor (GM-CSF) and 15 placebo during 7 consecutive days as subcutaneous injections. The GM-CSF group demonstrated significant increases in total white blood cell count (TWBC) and absolute neutrophil count (ANC) from the morning of the third day of the study. The study concludes that GM-CSF has an important therapeutic role in the treatment of febrile neutropenia that arises during intensive chemotherapy programmes but further studies of dosage and therapy duration are required, as is the development of methods of assessing bone marrow vitality.

Scintigraphy and biodistribution of monoclonal adrenocortical antibody in mice grafted with human adrenocortical carcinoma

BACKGROUND

A murine monoclonal antibody recognizing normal and neoplastic human adrenocortical cells has been evaluated for scintigraphic localization and biodistribution in 53 nude mice grafted subcutaneously with human adrenocortical cell lines SW-13 and T-CAR 1.

METHODS

The immunoglobulin G1 antibody and its Fab'2 fragment were purified and labeled with 125I. The tumor grafts exhibited diameters of 5 to 15 mm at 4 to 6 weeks after transplantation, when mice received a single subcutaneous or intraperitoneal injection of 50 micrograms iodinated intact or fragmented antibody, respectively.

RESULTS

Examination up to 8 days after immunoglobulin G administration showed mean radioactivity ratios less than 1.0 for tumor to blood and corresponding ratios in tumor to lung, liver, spleen, and kidney from 0.6 to 5.3 at the time of peak tumor to blood ratio. A high background activity was noted on scintigraphic tumor visualization with the iodinated immunoglobulin G. In contrast, the radiolabeled Fab'2 fragment displayed gradually rising tumor to blood ratios, which, 4 days after injection, averaged 10.5 for T-CAR1 and 5.3 for SW-13. Tumor transplants were scintigraphically visualized without substantial background activity 3 days after Fab'2 injection, when the ratio of radioactivity in the tumor to the investigated murine organs was 0.5 to 7.3.

CONCLUSIONS

The findings substantiate that immunoscintigraphy with the Fab'2 fragment of the antiadrenocortical Ac5 antibody may become a tool to localize human adrenocortical carcinoma.

Increased radioresistance of an in vitro transformed human small cell lung cancer cell line

After 4-6 months in continuous culture the human small cell lung cancer (SCLC) cell line, U-1906, changed its radiobiological characteristics spontaneously. The cell line became more radioresistant indicating an increased repair capacity. This change was accompanied by a more adherent growth pattern, a higher clonogeneity, a decrease in the cytokeratin (tissue polypeptide antigen) content and increased glucagon and neuron-specific enolase (NSE) production. Other parameters such as the estramustine-binding protein (EMBP) and the proliferation associated antigen Ki-67 were unaltered. This spontaneous transformation in vitro of U-1906 may reflect a clinically important in vivo phenomenon of SCLC, which frequently develops resistance both to radio- and chemotherapy.

Prolonged bleeding time during nitric oxide inhalation in the rabbit

During a study on the modulatory effect of inhaled nitric oxide (NO) on the airway, we observed an increased bleeding tendency. Therefore, we studied bleeding time and blood rheology in rabbits during inhalation of 3, 30 and 300 parts per million (ppm) NO. The rabbits were intubated during neurolept anaesthesia and were ventilated mechanically. The bleeding time was significantly increased after 15 min of inhalation of 30 ppm NO, from 51 +/- 5 to 72 +/- 7 s (mean +/- SEM, P < 0.001, n = 7). However, there were no changes in haematocrit, whole blood or plasma viscosity, erythrocyte aggregation tendency, or erythrocyte deformability. Inhalation of 3 ppm NO increased bleeding time from 46 +/- 11 to 59 +/- 8 s (n.s., n = 4) and 300 ppm NO from 48 +/- 12 to 78 +/- 17 s (P < 0.05, n = 4). In another group of rabbits mean arterial pressure (MAP) was monitored using NO inhalation. A non-significant decrease was seen with 3 ppm and 30 ppm NO, from 63 +/- 2 to 59 +/- 3 mmHg (n = 6) and from 65 +/- 2 to 61 +/- 1 mmHg (n = 6) respectively. Inhalation with 300 ppm NO decreased MAP from 62 +/- 3 to 55 +/- 2 mmHg (P < 0.05, n = 6). We conclude from these data that inhalation of NO, 30 ppm or more exerts systemic effects.

Effects of inhaled nitric oxide on methacholine-induced bronchoconstriction: a concentration response study in rabbits

Inhaled nitric oxide (NO), at a concentration of 80 ppm, counters the increase in respiratory resistance (Rrs) induced by methacholine, but fails to prevent a reduction in lung compliance (Crs) in a rabbit model. This study reports the effects of 3, 30 and 300 ppm of inhaled NO. New Zealand White rabbits were intubated and mechanically ventilated with 30% oxygen during neurolept anaesthesia. Methacholine (3 mg.ml-1) was nebulized, with or without NO inhalation. Inhalation of 3 and 30 ppm NO had no effect on the induced bronchoconstriction, whereas 300 ppm fully blocked the increase in Rrs. The decrease in Crs due to methacholine was not countered by 3, 30 or 300 ppm NO. On the contrary, inhalation of 300 ppm NO in itself decreased Crs from 5.0 +/- 0.1 to 4.3 +/- 0.1 ml.cmH2O-1. Also, mean arterial pressure (60 +/- 7 to 54 +/- 5 mmHg), alveolar-arterial oxygen tension gradient (0.8 +/- 0.8 to 2.3 +/- 1.8 kPa) and methaemoglobin (0.5 +/- 0.2 to 1.5 +/- 0.5%) changed significantly on inhalation of NO 300 ppm prior to methacholine challenge. We conclude that 3 and 30 ppm NO inhalation does not alter methacholine-induced bronchoconstriction. Inhalation of 300 ppm NO blocks an increase in resistance but fails to counter the reduction in compliance due to methacholine. This suggests that the bronchodilating effects of NO in rabbits in vitro are confined to the large airways.

Clinical and biochemical effects in vivo of monoclonal antitumor antibody in Verner-Morrison's syndrome

BACKGROUND

Monoclonal antibodies have not been evaluated in metastasizing endocrine tumors, even though these lesions may induce severe morbidity of hormone excess in absence of considerable tumor burden.

METHODS

A murine monoclonal antibody of the IgG2a subtype was generated by immunization with dispersed tumor cells from an endocrine pancreatic carcinoma associated with liver and peritoneal metastases as well as a therapy-resistant Verner-Morrison's syndrome.

RESULTS

Immunohistochemical staining disclosed selective tissue reactivity of the antibody and conspicuous immunostaining on the surface of the tumor cells. Infusion of 100 mg antibody over 2 days into the common hepatic artery of the patient was accompanied by reduced diarrhea volume until death 6 weeks later and transient elevation of total plasma immunoreactivity for vasoactive intestinal peptide due to large molecular forms of the peptide. Postmortem examination demonstrated disappearance of peritoneal metastases as well as absence of immunostaining for the injected antibody and the transferrin receptor within residual hepatic tumors.

CONCLUSION

The results substantiate that symptomatic alleviation and perhaps interference with tumor cell mass may be obtained with monoclonal antibodies in patients with endocrine tumors and that the antiidiotypic immunoglobulin response may play a role herein.

Inhalation of nitric oxide modulates methacholine-induced bronchoconstriction in the rabbit

Nitric oxide (NO) accounts for the major effects of endothelium-derived relaxing factor. We investigated whether NO, added to the inspired gas, could exert a bronchodilatory action similar to the pulmonary vasodilation described when administering NO during lung vascular constriction. New Zealand White rabbits were intubated and mechanically-ventilated with 30% oxygen during neuroleptanaesthesia. Methacholine (MCh) was nebulized at increasing concentrations from 0.5 to 4.0 mg.ml-1, with or without inhalation of 80 parts per million (ppm) NO. The technique of rapid airway occlusion during constant-flow inflation was used for measuring respiratory mechanics, i.e. resistance and compliance of the respiratory system. Methacholine nebulization without NO inhalation raised the resistance from 51 +/- 6 (mean +/- 95% confidence interval) to 107 +/- 52 cmH2O.l-1.s at Mch 4 mg.ml-1. During NO inhalation, nebulization of MCh showed no significant increase in resistance. Arterial oxygen tension (PaO2) and compliance fell to the same extent during methacholine challenge, whether NO was inhaled or not. Closure of small airways may be a mechanism that causes the decrease in PaO2 and compliance observed. This suggests that 80 ppm NO added to the inspired gas modulates the response in central airway tone to nebulized MCh in this rabbit model. However, it appears to have less effect on peripheral airways.

Inhalation of nitric oxide modulates methacholine-induced bronchoconstriction in the rabbit

Nitric oxide (NO) accounts for the major effects of endothelium-derived relaxing factor. We investigated whether NO, added to the inspired gas, could exert a bronchodilatory action similar to the pulmonary vasodilation described when administering NO during lung vascular constriction. New Zealand White rabbits were intubated and mechanically-ventilated with 30% oxygen during neuroleptanaesthesia. Methacholine (MCh) was nebulized at increasing concentrations from 0.5 to 4.0 mg.ml-1, with or without inhalation of 80 parts per million (ppm) NO. The technique of rapid airway occlusion during constant-flow inflation was used for measuring respiratory mechanics, i.e. resistance and compliance of the respiratory system. Methacholine nebulization without NO inhalation raised the resistance from 51 +/- 6 (mean +/- 95% confidence interval) to 107 +/- 52 cmH2O.l-1.s at Mch 4 mg.ml-1. During NO inhalation, nebulization of MCh showed no significant increase in resistance. Arterial oxygen tension (PaO2) and compliance fell to the same extent during methacholine challenge, whether NO was inhaled or not. Closure of small airways may be a mechanism that causes the decrease in PaO2 and compliance observed. This suggests that 80 ppm NO added to the inspired gas modulates the response in central airway tone to nebulized MCh in this rabbit model. However, it appears to have less effect on peripheral airways.

Distribution and elimination of the somatostatin analogue (111In-DTPA-D-Phe1)-Octreotide (OctreoScan111)

The distribution and elimination characteristics of the 111In-labelled somatostatin analogue OctreoScan111 were studied in 23 patients with malignant tumours. The substance exhibited a rapid blood elimination following a bi-phasic pattern. The initial part of the elimination curves showed a t1/2a of between 0.27 and 3.6 h. The patients investigated had creatinine clearance rates ranging from 33 to 124 ml/min. However, within this range, no apparent correlation was found between the OctreoScan111 elimination rate and kidney function. Also no correlation was observed between the amount of administered activity and the elimination rate of OctreoScan111. The serum radioactivity of 6 patients was analyzed with respect to molecular size. These experiments showed that OctreoScan111 circulated unbound in serum. About 3% of the radioactivity, most probably representing 111In-chloride of DTPA-111In-chloride, circulated protein-bound. The elimination of OctreoScan111 radioactivity in urine displayed a bi-phasic pattern. Size separation of the radioactivity appearing in the urine after 24 h showed a higher molecular weight when compared with OctreoScan111, indicating the existence of a metabolite of the injected substance. The results obtained are discussed in the light of a potential role for the substance in systemic radiotherapy.

Somatostatin receptor scintigraphy of carcinoid tumours using the [111In-DTPA-D-Phe1]-octreotide

Somatostatin-receptor scintigraphy using the 111In-labelled somatostatin-analogue octreotide ([111In-DTPA-D-Phe1]-octreotide) was performed in 40 patients with carcinoid tumours. In 31/40 patients, this scintigraphy proved positive compared with the 33/40 patients whose tumours were disclosed on CT scans. In addition, 18 previously unidentified lesions were detected with this scintigraphy. Two of these lesions represented previously undetectable primary tumours. It is concluded that somatostatin receptor scintigraphy using [111In-DTPA-D-Phe1]-octreotide has a future role in the staging of patients with carcinoid disease.

Immunotargeting with monoclonal cytokeratin 8 antibodies of human urothelial cancer transplanted to nude mice

The possibility of using cytokeratin antibodies for the radioimmunolocalization of urinary bladder cancer was studied. A monoclonal murine IgG antibody was raised against cytokeratin 8 and labelled with iodine-125; normal murine IgG was used for control purposes. The urothelial cancer cell line RT4 was transplanted into immunodeficient nude mice. The anti-cytokeratin 8 antibody was administered intraperitoneally and its uptake in the tumour and other organs was analyzed with a computerized gamma camera. Optimal scintigraphic visualization occurred 11 days after antibody administration. The tumour/blood ratio of the specific antibody was 5.64 (+/- 5.01 SD) on day 11, compared with 0.73 (+/- 0.35 SD) in the control. Autoradiography demonstrated antibody uptake preferentially in viable sections of the tumour. The antibody uptake is presumed to be the result mainly of binding to the released cytokeratin in and around cells lysed during natural cellular death. The monoclonal murine anti-cytokeratin antibody is of potential interest in studies aimed at improving the clinical staging of urinary bladder cancer.

Characterization and uptake of radiolabelled meta-iodobenzylguanidine (MIBG) in a human neuroblastoma heterotransplant model in athymic rats

Cells from an established human neuroblastoma cell line, SH-SY5Y, were demonstrated to grow and form solid tumours in nude rats. This cell line, which is an adrenergic subclone of the SK-N-SH cell line, has previously been used in differentiation model studies. The tumours retained the neuronal phenotype of the cultured cells, as evidenced by the expression of neuron-specific enolase (NSE) and chromogranin A + B. The transcription factor Isl-1, a protein expressed in subsets of neurons and endocrine cells as well as in neuroblastoma cells, was also expressed in the transplanted tumours, thus further verifying the retained phenotype of the cells under in vivo conditions. At scintigraphy utilizing 123I-MIBG the optimal tumour/background ratio was obtained 20 h after injection. The assessment of tissue/serum ratios showed the highest uptake in the spleen (0.067% per gram of inj. activity), neuroblastoma tumours (0.067% per gram of inj. activity) and in the adrenals (0.065% per gram of inj. activity).

Distribution of monoclonal antiparathyroid antibody E11 in mice grafted with human parathyroid adenoma and carcinoma

One hundred six immunoincompetent mice grafted with human parathyroid adenoma or carcinoma were used to evaluate distribution of the murine monoclonal antibody E11, which recognizes a calcium sensor of high molecular weight on the parathyroid cell surface. The subcutaneous parathyroid grafts were infiltrated with murine fibrous tissue, which seemed to increase with the duration of transplantation and the size of inserted tissue pieces. Intraperitoneal injection of biotinylated or 125I-labeled E11 antibody indicated time- and dose-dependent antibody accumulation, as well as the presence of unoccupied binding sites in the transplanted parathyroid tissue. The iodinated intact immunoglobulin G and Fab fragment of the E11 antibody demonstrated low radioactivity in the lung, liver, spleen, kidney, and intestine for up to 14 days, except for the Fab fragment, which was rapidly accumulated and cleared from the kidney. The peak radioactivity ratio in the adenoma tissue versus blood averaged 2.8 for the intact antibody and 5.3 for the Fab fragment, whereas the corresponding values for the carcinoma tissue were 8.6 and 8.8, respectively. These ratios increased considerably, especially for the adenoma specimens, when weights of the excised grafts were adjusted for the calculated content of parathyroid tissue. The results support that the E11 antibody may localize even minute amounts of human parathyroid adenoma and carcinoma tissue.

Silver stains for identification of neuroendocrine cells. A study of the chemical background

The chemical background of silver stains used for visualization and characterization of peripheral neuroendocrine cells in the gastrointestinal tract and pancreas, and of their corresponding tumours, was studied in tissue sections and by a dot-blot technique. Sequential staining of pancreatic islets with an immunohistochemical procedure and silver staining of the same tissue section revealed that chromogranin A immunostained cells also displayed an argyrophil reaction with the Grimelius method, but no argentaffin reaction with the Masson technique. Accordingly, purified chromogranin A (15 micrograms or less) treated in formalin and applied to nitrocellulose did not show any argentaffin reaction but displayed a dose-related argyrophil reaction. Equal quantities of other polypeptide components did not give rise to any silver reaction. Further dot-blot studies showed that the tryptophan and tyrosine metabolites, dopamine, norepinephrine, 5-hydroxytryptamine and 5-hydroxinodole caused strongly argentaffin and argyrophil reactions while epinephrine, 5-hydroxyindole-3-acetic acid and 5-hydroxytryptophan gave only the former reaction. Among other chemical components studied, only guanine displayed weak silver staining. The results indicate that the reaction products between aldehydes and the granular content of biogenic amines synthesized from tryptophan and tyrosine display an argentaffin reaction and that the granular chromogranin A caused an argyrophil but no argentaffin reaction.

Neuroendocrine pancreatic tumours: clinical presentation, biochemical and histopathological findings in 84 patients

A prospective study has been performed on 84 patients with endocrine pancreatic tumours evaluated at the Medical Department in Uppsala. Available information concerning the patients' presenting symptoms, age at diagnosis, clinical syndrome, tumour location, location of metastases, diagnostic radiology, biochemical and histopathological findings has been analysed. Our results indicate that most patients initially show rather vague and non-specific symptoms, with dyspepsia and pain being the most frequent presenting features. The median delay between appearance of the first symptom and diagnosis was 2 years; the delay was 35 months in sporadic cases and 14.5 months in familial cases. In spite of improvements in diagnostic methods, the median age at diagnosis (53 years) has not been reduced, and most patients are encountered when the tumour has reached an advanced stage. There is a need for a method of screening patients with still uncharacteristic abdominal symptoms for a neuroendocrine tumour. The presence of elevated levels of plasma chromogranin in all patients with a proven tumour suggests that such possibilities exist, and the use of this biochemical marker in the future might reduce the age at diagnosis and thus improve the likelihood of cure and survival of patients with endocrine pancreatic tumours.

A polyclonal antiserum against chromogranin A and B--a new sensitive marker for neuroendocrine tumours

Chromogranins A, B, and C, proteins that are co-stored and co-released with peptides and amines, have been identified in a variety of neuroendocrine tissues, both normal and neoplastic. We examined the secretion of chromogranin A and chromogranin A + B by hormone-producing tumours in patients with endocrine pancreatic tumours, carcinoid tumours, pheochromocytomas, and small cell lung cancer. The radioimmunoassay determining the plasma concentrations of chromogranin A + B showed a greater sensitivity than that determining chromogranin A alone. All patients with endocrine pancreatic tumours, carcinoids, and pheochromocytomas had increased levels of chromogranin A + B, whereas a small number of the patients (5/18 with endocrine pancreatic tumours and 1/3 with pheochromocytomas) had normal levels of chromogranin A. Also in immunocytochemical stainings, our polyclonal antiserum detecting both chromogranin A and B showed a greater sensitivity than other available antisera against chromogranin A, B and C. We have demonstrated that a polyclonal antiserum against a mixture of chromogranin A and B might be a more sensitive marker than chromogranin A alone for diagnosing neuroendocrine tumours. This is not surprising, since both chromogranins are widely distributed in neuroendocrine cells.

Chromogranins--new sensitive markers for neuroendocrine tumors

Chromogranins A, B and C, proteins that are costored and coreleased with peptides and amines, have been identified in a variety of endocrine and nervous tissues, both normal and neoplastic. We examined the secretion of chromogranin A and chromogranin A + B by hormone-producing tumors in patients with endocrine pancreatic tumors (EPT), carcinoid tumors, pheochromocytomas and small cell lung cancer (SCLC). Radioimmunoassay (RIA) of the plasma/serum concentrations of chromogranin A + B showed a greater sensitivity than RIA of chromogranin A alone. All patients with EPT, carcinoids and pheochromocytomas had increased levels of chromogranin A + B, whereas a small number of the patients (5/18 with EPT and 1/3 with pheochromocytomas) had normal levels of chromogranin A. Also in immunocytochemical stainings, our polyclonal antiserum detecting both chromogranin A and B showed a greater sensitivity than other available antisera against chromogranin A, B and C.

The release of chromogranin A and B like activity from human lung cancer cell lines. A potential marker for a subset of small cell lung cancer

Human small cell lung cancer (SCLC) is in vivo and in vitro characterized by a heterogeneous spectrum of neuroendocrine markers. The non-SCLC group is deprived of these markers, or expresses them in low quantities. In this paper we report on the release to the culture medium of neuroendocrine associated proteins, chromogranin A and B like activity (CABLA). The culture medium from three out of five SCLC cell lines and in one/five non-SCLC cell line contained significant levels of CABLA. Normal diploid foreskin fibroblasts and a histiocytic lymphoma cell line were deprived of CABLA production. The presence of CABLA in both SCLC and non-SCLC further stress their common histogenetic origin. The CABLA values were partly unrelated to other neuroendocrine markers. Determinations of CABLA could thus be a potential and valuable marker for a subset of SCLC.