Secondary antibodies as tools to improve tumor to non tumor ratio at radioimmunolocalisation and radioimmunotherapy

One way of selectively improving the efficiency of radioimmunolocalization and radioimmunotherapy is to eliminate redundant, circulating, non-targeting radiolabeled antibodies after saturation of the target sites. Secondary antibodies of different types have been proposed as clearing agents for such purposes. The conceptually different approaches of the 'secondary antibody' strategy including its advantages and limitations are discussed. This mini-review also presents a model describing the kinetics of the components (the antigen, the primary and secondary antibodies) and approaches required to improve the efficacy of both radioimmunolocalization and radioimmunotherapy.

Biological malignancy grading in early-stage ovarian carcinoma

The usefulness of adjuvant therapy in early ovarian cancer is a matter of controversy and there is a need for predictive methods to distinguish between low and high risk patients. Specimens from 95 early-stage ovarian cancer patients have been analysed for conventional clinical variables as well as for the biological markers--DNA content, MIB-1, p53, WAF-1--and correlated to survival. Prognostic significance achieved in univariate analysis could be improved by using a score based on several biological markers. Using a score based on DNA content, MIB-1, p53 and WAF-1, a significant predictor could be achieved with the aim of determining the postsurgical therapy. By using this tool, it is hoped that adjuvant therapy can be avoided for one-third of the patients with early-stage ovarian cancer.

Stepwise prediction of dental caries in children up to 3.5 years of age

The present study is a part of a prospective, longitudinal investigation of caries development in children (n = 692) living in the southern suburbs of Stockholm. The aim was to evaluate, longitudinally, the caries-predictive ability of variables describing social and immigrant background, dietary habits, microbial and oral hygiene factors, and fluoride exposure in children at 1 and 2.5 years of age with respect to caries development before the age of 3.5. The predictors for caries development in children before 2.5 years of age were mutans streptococci (p < 0.01), immigrant background (p < 0.01), and consumption of candy (p < 0.01). The predictors for developing manifest caries between 2.5 and 3.5 years of age were mutans streptococci (p < 0.001), mother's education (p < 0.001), immigrant background (p < 0.01), and consumption of candy (p < 0.05) and sugar-containing beverages (p < 0.05). The caries incidence at 2.5 years of age as well as the caries increment between 2.5 and 3.5 years of age were significantly higher in children with immigrant background compared to non-immigrants. This study indicates that the possibility of identifying children at risk for caries development increases longitudinally from 1 to 3.5 years of age and there was a synergistic effect between age and each predictor.

Use of anticytokeratin monoclonal anti-idiotypic antibodies to improve tumor:nontumor ratio in experimental radioimmunolocalization

A syngeneic, high-affinity, anti-idiotypic monoclonal antibody (MAb; alpha TS1) raised against an anticytokeratin monoclonal antibody (TS1) was evaluated as a second antibody to promote the rapid clearance of radiolabeled TS1 from the blood during experimental radioimmunolocalization. By using a novel biosensor technology (BIAcore), association rate dissociation rate, and affinity constants between the idiotype and the anti-idiotype could be determined. The in vivo results in nude mice carrying HeLa Hep 2 tumors demonstrate the possibility of selectively regulating the amount of the idiotypic 125I-labeled circulating MAb by in vivo injection of this high-affinity, anti-idiotypic antibody. Injection of the anti-idiotype in a molar ratio of 0.75 to the idiotype cleared the blood pool from circulating radiolabeled idiotype within 24 h, with a concomitant rapid excretion of 125I in urine. The total amount of remaining radioactivity in the animals decreased to 15-20% during these 24 h, with the tumors still retaining 60-65% of their initial radioactivity. This approach, using syngeneic primary and secondary MAbs with minimized immunogenicity, significantly improves the tumor:nontumor ratio, thus improving efficiency in experimental radioimmunolocalization and radioimmunotherapy, leaving the endogenous antibody repertoire of the host unaffected.

Risk factors for acute graft-versus-host disease in 291 consecutive HLA-identical bone marrow transplant recipients

We analysed 35 risk factors for acute GVHD in 291 consecutive recipients of HLA-identical sibling marrow transplants from 1975 to 1993. Of these, 16% developed moderate-to-severe acute GVHD following transplantation. In multivariate analysis, GVHD prophylaxis with monotherapy (MTX or CsA) (P = 0.015) seropositivity for several herpes viruses in the donor (P = 0.015) and seropositivity for CMV in the recipient (P = 0.037) before the transplants as well as early engraftment (P = 0.016), were the principal risk factors for GVHD. A high serum TNF-alpha level during conditioning therapy was also a significant risk factor in 75 recipients (P = 0.005). The risk of grades II-IV acute GVHD increased with the number of risk factors. Thus the cumulative incidence of acute GVHD was 1%, if no risk factor was present, 4% with one, 9% with two, 21% with three and 44% in patients with four risk factors. Factors reported to correlate with acute GVHD, such as age, diagnosis, female donor to male recipient, relative response and donor-responding capacity in MLC, MNS blood group antigen, splenectomy and bone marrow cell dose were not associated with acute GVHD in this study. Five-year survival was 24% in patients with grades II-IV GVHD vs 62% in patients with grades 0-I GVHD (P = 0.0001).

Prognostic value of amplification of c-erb-B2 in bladder carcinoma

Amplification of c-erb-B2 is examined in patients with transitional cell bladder carcinoma. In a pilot study we found that the amplification correlated with high tumor grade. Tumor grade is a known prognostic factor. Therefore, we next examined the prognostic value of c-erb-B2 amplification in patients with >16 years of clinical follow-up. The gene copy number was determined, using semiquantitative PCR, in archival formalin-fixed tissues. Twenty-three percent (37/163 patients) showed the amplification. The amplification correlated with grade and stage. Moreover, we found that tumor grade (P < 0.001) and c-erb-B2 amplification (P < 0.001) showed prognostic information for survival. Patients with grade 3 tumors and concomitant c-erb-B2 amplification showed the worst prognosis. Multivariate analysis indicates that grade and c-erb-B2 amplification are independent prognostic factors.

Inflammation reduces mucosal secretion of hydrogen ions and impairs concentrating function and luminal acidification in feline gallbladder

BACKGROUND

The gallbladder mucosa normally absorbs fluid and secretes H+ ions. The fluid secretion in inflamed gallbladders is induced by prostaglandins and mediated by intramural vasoactive intestinal peptide (VIP)-ergic nerves.

METHODS

The influence of inflammation on gallblader contents due to secretion of H+ into the lumen. In animals with inflamed gallbladder this acid secretion was reduced; there was secretion of HCO3- and no evident acidification of the gallbladder contents. Injection of VIP antiserum or indomethacin restored H+ secretion and inhibited HCO3- and fluid secretion by the inflamed gallbladder mucosa. An impaired acidification of the gallbladder contents due to mucosal inflammation may reduce the solubility of calcium salts in gallbladder bile and increase the risk of their precipitation in the lumen.

CONCLUSION

Mucosal inflammation reduces H+ secretion and impairs acidification of the gallbladder contents.

Synthesis of an N-methyldehydroalanine-containing fragment of microcystin by combination of solid phase peptide synthesis and beta-elimination in solution

A new method for the synthesis of dehydroalanine (delta Ala)-containing peptides has been developed by combining solid phase peptide synthesis (tert-butyloxycarbonyl/HF-chemistry) with solution synthesis. A sequence from cyanobacterial hepatotoxin microcystin, Ac-D-gamma-Glu-[N-Me-delta Ala]-D-Ala-Leu amide was chosen as a model peptide. The precursor for the synthesis of the dehydroalanine-containing peptide, Ac-D-gamma-Glu-[N,S-diMeCys]-D-Ala-Leu, was synthesized on a solid phase followed by sulfonium salt formation on the resin. The resulting S,S-dimethylated peptide was cleaved from the resin with liquid HF. The HPLC-purified S,S-dimethylated cysteine-containing precursor peptide was subjected to beta-elimination in solution catalysed by DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) in methanol. The final product, Ac-D-gamma-Glu-[N-Me-delta Ala]-D-Ala-Leu amide, was purified by HPLC, and analysed by mass spectrometry and 1H NMR spectroscopy. The stability of the model peptide under acidic, neutral and basic conditions has been studied.

Antibody engineering

Antibody engineering has been an extremely intensive research area for many years. Recent achievements discussed in this review include: (i) significant improvements in the field of selection of antigen-specific antibody fragments on bacteriophages; (ii) new structural work, in particular using NMR; (iii) the cloning of essentially the complete set of human VH genes; (iv) the use of antibodies to catalyze complicated chemical reactions; and (v) novel antibody fusion proteins to potentiate immune therapy. An interesting new development is the replacement of antibodies with more stable protein scaffolds for many future biotechnological applications.

Effects of 12 weeks of ramipril treatment on the quality of life in patients with moderate congestive heart failure: results of a placebo-controlled trial. Ramipril Study Group

The assessment of quality of life (QoL) has become recognized as an important tool for evaluating heart failure therapy. The angiotensin-converting enzyme inhibitor ramipril (mean dose 8 mg) was evaluated in 223 patients with moderate chronic congestive heart failure at 24 centers in 4 Nordic countries following a randomized, double-blind, placebo-controlled, parallel group design. The follow-up period was 12 weeks. QoL was evaluated using a questionnaire with 47 items, including the disease-specific Severe Heart Failure Questionnaire, the Sleep Dysfunction Scale, and the Psychological General Well-Being Index. In both treatment groups the total score increased from baseline to 12 weeks for both the Severe Heart Failure Questionnaire and for the Psychological Well-Being Index, reflecting relief of symptoms and improved well-being. However, no significant differences between the placebo and ramipril groups could be detected. Only a trend toward improvement in sleep on ramipril compared with placebo therapy was observed. In conclusion, in this placebo-controlled trial no significant effects of 12-week ramipril treatment of QoL could be demonstrated in patients with moderate congestive heart failure.

Role of nitric oxide in motility and secretion of the feline hepatobiliary tract

BACKGROUND

Nitric oxide (NO) mediates inhibition of gastrointestinal smooth-muscle cells via nonadrenergic, non-cholinergic (NANC) nervous pathways. The effect of NO on the absorption and secretion by the mucosa of the gastrointestinal and hepatobiliary tracts is less well known. The aim of this study was to evaluate the effects of a pharmacologic blockade of NO synthase on sphincter of Oddi activity, gallbladder function, and bile secretion and to demonstrate the presence of NO synthase-positive neurons in this region.

METHODS

Experiments were conducted on anesthetized cats after blockage of noradrenergic and cholinergic neurotransmission. Flow resistance in the sphincter of Oddi, gallbladder fluid absorption and motility, bile outflow from the liver, and bile salt secretion were registered.

RESULTS

Flow resistance exerted by the sphincter of Oddi increased dose-dependently in response to the NO synthase blocker NG-nitro-L-arginine. The increase in flow resistance was reversed stereospecifically by L-arginine, the substrate for NO synthesis. No significant effects on bile secretion, gallbladder fluid transport, or gallbladder motility were observed. NO synthase-positive neurons were identified close to the sphincter of Oddi and in the gallbladder mucosa.

CONCLUSIONS

This tonically active inhibitory NANC innervation of the sphincter of Oddi may be important in the physiologic regulation of the bile duct pressure.

Bile cytology. Diagnostic role in the management of biliary obstruction

Thirty satisfactory bile specimens from 21 patients (13 with cancer and 8 with benign conditions) were reviewed to assess the diagnostic role of bile cytology in the management of biliary obstruction. Smears were malignant in 5 instances, suspicious in 1, atypical in 2 (8 in the positive group) and negative in 22. There were no false positives. The diagnostic sensitivity was 38%, specificity 100% and overall accuracy 57%. Of interest were (1) hepatocellular carcinoma, causing obstruction in three patients; (2) metastatic colonic adenocarcinoma, causing obstruction in another instance; (3) positive cytodiagnosis in a patient who developed biliary stricture following laparoscopic cholecystectomy; and (4) detection of acidfast bacilli in bile from a case of tuberculous pseudotumor mimicking a hepatic malignancy. Bile cytology is a simple, inexpensive means of obtaining tissue confirmation of neoplastic and specific inflammatory causes of biliary obstruction. It is a useful adjunct to other techniques in this era of fiberoptic diagnostic procedures. Cell block sections should be prepared whenever possible.

Kinetic analysis of the interaction between protein A domain variants and human Fc using plasmon resonance detection

A real-time biospecific interaction analysis (BIA) was performed to study the specific interaction between the Fc portion of human immunoglobulin G1 (Fc1) and a one domain analogue (designated Z) of staphylococcal protein A, in monovalent (Z) and divalent (ZZ) forms, and five different single amino acid substituted Z variants (L17D, N28A, F30A, I31A, K35A). Experimental BIA data were used to calculate association rate constants (kon), dissociation rate constants (koff) and affinity constants (Kaff). The divalent form (ZZ) showed a higher affinity for Fc1 mainly because of a slower off rate. Out of the five mutant Z proteins, four (L17D, N28A, I31A, K35A) showed a decreased affinity to Fc1 compared to the parent Z molecule. Surprisingly, two (L17D, I31A) of these four had the major effect of a decreased binding energy as a lowered kon while the other two (N28A, K35A) mutant proteins showed an increased koff as the major kinetic difference from Z in their binding to Fc1. For five of the six different Z variants, as well as for the ZZ molecule, calculated Kaff and calculated differences in binding free energies relative to the parent Z molecule (delta delta G), are in good agreement with the corresponding values obtained in a competitive displacement assay using radioactively labeled Z as a tracer (Cedergren et al., (1993) Prot. Eng. 6, 441-448). However, the I31A variant, with a measured kon that was more than three orders of magnitude lower than that of Z in the BIA assay, showed a significantly weaker affinity to Fc1 when calculated from the BIA data compared to the competitive displacement assay. The discrepancy between these two methods for Z(I31A) is discussed as well as possible explanations for the unexpected large effect of lowered kon for two of the mutant Z proteins.

Phosphorylation of complement component C3 and C3 fragments by a human platelet protein kinase. Inhibition of factor I-mediated cleavage of C3b

Phosphorylation of C3 in vitro has been shown previously to lead to significantly altered function of the protein. Platelets are known to contain and release considerable amounts of protein kinases and ATP, which are prerequisites for protein phosphorylation. The aim of the present study was to investigate whether C3 is phosphorylated extracellularly by human platelets. Platelet-rich plasma was stimulated by human aggregated gamma-globulin or ADP. The remaining cells were removed by centrifugation, and the plasma was incubated with [gamma-32P]ATP. After precipitation with Sepharose-bound Abs to C3c followed by SDS-PAGE, it was shown that C3 was phosphorylated in the alpha-chain by a protein kinase dependent on Mn2+, Ca2+, or Mg2+ ions. The supernatant from washed, activated platelets was incubated with purified C3 or soluble or activated thiol Sepharose-bound C3b, together with [gamma-32P]ATP. Phosphorylation was seen in the alpha-chain of C3, and to the same extent in the alpha'-chain of both C3b preparations. The analysis of acid hydrolysate demonstrated that C3 contained 32P-labeled Thr and 32P-labeled Ser. After extensive proteolysis with trypsin, the major phosphorylation site was located to a peptide of 3 to 4 kDa that was bound to the activated thiol Sepharose via the free sulphydryl group in the C3d fragment. Incubation of phosphorylated C3b with factors I and H showed that phosphorylation inhibited the cleavage of the alpha'-chain of C3b. The results in this study suggest that phosphorylation is a regulator of C3 during platelet activation induced, for example, by immune complexes.

Phosphorylation of complement component C3 and C3 fragments by a human platelet protein kinase. Inhibition of factor I-mediated cleavage of C3b

Phosphorylation of C3 in vitro has been shown previously to lead to significantly altered function of the protein. Platelets are known to contain and release considerable amounts of protein kinases and ATP, which are prerequisites for protein phosphorylation. The aim of the present study was to investigate whether C3 is phosphorylated extracellularly by human platelets. Platelet-rich plasma was stimulated by human aggregated gamma-globulin or ADP. The remaining cells were removed by centrifugation, and the plasma was incubated with [gamma-32P]ATP. After precipitation with Sepharose-bound Abs to C3c followed by SDS-PAGE, it was shown that C3 was phosphorylated in the alpha-chain by a protein kinase dependent on Mn2+, Ca2+, or Mg2+ ions. The supernatant from washed, activated platelets was incubated with purified C3 or soluble or activated thiol Sepharose-bound C3b, together with [gamma-32P]ATP. Phosphorylation was seen in the alpha-chain of C3, and to the same extent in the alpha'-chain of both C3b preparations. The analysis of acid hydrolysate demonstrated that C3 contained 32P-labeled Thr and 32P-labeled Ser. After extensive proteolysis with trypsin, the major phosphorylation site was located to a peptide of 3 to 4 kDa that was bound to the activated thiol Sepharose via the free sulphydryl group in the C3d fragment. Incubation of phosphorylated C3b with factors I and H showed that phosphorylation inhibited the cleavage of the alpha'-chain of C3b. The results in this study suggest that phosphorylation is a regulator of C3 during platelet activation induced, for example, by immune complexes.

In vivo and in vitro interactions between idiotypic and antiidiotypic monoclonal antibodies against placental alkaline phosphatase

A monoclonal antiidiotypic antibody alpha H7, was generated against a monoclonal antibody H7 with specificity towards placental alkaline phosphatase. The in vitro and in vivo effects of alpha H7 were investigated. The antiidiotypic antibody was found to generate stable complexes with the radiolabeled idiotypic antibody, visualized both in vivo and in vitro, as revealed by PAGE and autoradiography. Using biosensor technology (BIAcore, Pharmacia) the interactions were followed in real time and the association rate, dissociation rate, and affinity constants between the reactants were determined (KA H7/PLAP 6.7 x 10(9) M-1, KA H7/alpha H7 3.2 x 10(9) M-1). By in vivo injection of the antiidiotype, a rapid dose dependent clearance of circulating radiolabeled idiotypes was demonstrated and a decrease in total body radioactivity was recorded with a concomitant dramatic increase in non-protein-bound 125I excreted in the urine. It is concluded that idiotypic-antiidiotypic interactions offer advantages in the regulation of antibody levels in vivo.

Direct and competitive kinetic analysis of the interaction between human IgG1 and a one domain analogue of protein A

Direct and competitive kinetic analysis of the binding between a one domain analogue of protein A, and mutants thereof, to immobilised hIgG1 was compared using a biosensor system based on surface plasmon resonance detection. Rate constants determined from both assays were almost identical. The experiments demonstrate that competitive kinetic analysis can be used in combination with biosensor technology, and indicate that competitive kinetic analysis may extend the use of the technology to include low molecular weight analytes.

Prognostic value of erb-B2 and myc amplification in breast cancer imprints

BACKGROUND

Amplification of erb-B2 and myc shows prognostic value in patients with operable breast cancer. Amplification is usually detected in tumor samples remaining after pathologic work-up, preventing the examination of small tumors.

METHODS

Tumor imprints that contained low numbers of contaminating normal cells were obtained from small tumors. The prognostic value of erb-B2 and myc amplification in imprint breast preparations was examined, using the polymerase chain reaction (PCR) to determine gene copy number. Tumor material was obtained from 162 patients with breast cancer operated 1975-1976.

RESULTS

Amplification of erb-B2 existed in 21% and myc in 16% of the patients. Both erb-B2 and myc amplification showed prognostic significance in univariate analysis for survival and relapse free survival. In multivariate analysis, erb-B2 was a significant factor. In small tumors less than 13 mm in greatest dimension, erb-B2 showed prognostic significance for survival but not for relapse free survival.

CONCLUSIONS

The use of imprints/PCR allows the detection of gene amplification in breast cancer. The procedure is suitable for the analysis of small tumors and can be used to examine very small tumors, such as those detected mammographically.

A combinatorial library of an alpha-helical bacterial receptor domain

The construction and characterization of a combinatorial library of a solvent-exposed surface of an alpha-helical domain derived from a bacterial receptor is described. Using a novel solid-phase approach, the library was assembled in a directed and successive manner utilizing single-stranded oligonucleotides containing multiple random substitutions for the variegated segments of the gene fragment. The simultaneous substitution of 13 residues to all 20 possible amino acids was carried out in a region spanning 81 nucleotides. The randomization was made in codons for amino acids that were modelled to be solvent accessible at a surface made up from two of the three alpha-helices of a monovalent Fc-binding domain of staphylococcal protein A. After cloning of the PCR-amplified library into a phagemid vector adapted for phage display of the mutants, DNA sequencing analysis suggested a random distribution of codons in the mutagenized positions. Four members of the library with multiple substitutions were produced in Escherichia coli as fusions to an albumin-binding affinity tag derived from streptococcal protein G. The fusion proteins were purified by human serum albumin affinity chromatography and subsequently characterized by SDS-electrophoresis, CD spectroscopy and biosensor analysis. The analyses showed that the mutant protein A derivatives could all be secreted as soluble full-length proteins. Furthermore, the CD analysis showed that all mutants, except one with a proline introduced into helix 2, have secondary structures in close agreement with the wild-type domain. These results proved that members of this alpha-helical receptor library with multiple substitutions in the solvent-exposed surface remain stable and soluble in E. coli.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspiration cytology of liver abscesses. With an emphasis on diagnostic pitfalls

Clinical and imaging features of liver abscesses are not specific. Necrotic hepatic neoplasms, primary or secondary, can mimic abscesses, and vice versa. Thirty-eight patients who had cytologic confirmed abscesses were analyzed. There was clinical, radiologic and cytologic concurrence in 27 patients. In six cases the clinically suspicious lesion turned out to be inflammatory. The remaining five were malignant. There were four amebic and three tuberculous cases in this series. Cytologically, pyogenic abscesses contained a heavy, neutrophilic, inflammatory exudate with nuclear debris. By comparison, amebic cases contained more necrotic debris, with degenerating hepatocytes and fewer inflammatory cells. Acid-fast bacilli were identified in two tuberculous abscesses; however, only one contained caseous necrotic material and epithelioid cells. A potential pitfall in the cytologic diagnosis of a case of inflammatory pseudotumor is emphasized. The diagnosis of liver abscess should be established by clinical and imaging findings in conjunction with needle aspiration.

Tuberculous pseudotumor causing biliary obstruction. Report of a case with diagnosis by fine needle aspiration biopsy and bile cytology

Hepatobiliary tuberculosis is a rare but distinct clinical entity. We report an unusual case of biliary tract obstruction due to localized hepatic tuberculosis with periportal tuberculous adenitis. The lesion mimicked a malignancy clinically and radiologically. Fine needle aspiration biopsy revealed granulomas, epithelioid histiocytes and Langhans' giant cells. The cytodiagnosis was confirmed by identification of acid-fast bacilli in the bile cytology and isolation of Mycobacterium tuberculosis by culture. The patient responded to antituberculosis therapy. The usefulness of bile cytology in the diagnostic management of biliary tract obstruction is illustrated.

The influence of VDT work on musculoskeletal disorders

Relationships between visual display terminal (VDT) use and musculoskeletal problems were examined in a group of 353 office workers, using data from medical and workplace investigations as well as questionnaires. There were no general differences between VDT and non-VDT users as to the occurrence of muscle problems. Combinations of specific VDT work situations such as data entry work or work with a VDT for more than 20 h/week and the presence of some other factors were, however, associated with excess risks of certain muscle problems. The extraneous factors involved in the definitions of such risk groups were: use of bifocal or progressive glasses at a VDT; stomach-related stress reactions; limited rest break opportunity; repetitive movements; non-use of lower arm support; and possibly the vertical position of the keyboard; and presence of specular glare.

Musculoskeletal disorders among visual display terminal workers: individual, ergonomic, and work organizational factors

A number of individual, ergonomic, and organizational factors of presumed importance for the occurrence of musculoskeletal disorders were investigated in a group of 260 visual display terminal (VDT) workers. The cross-sectional study utilized medical and workplace investigations as well as questionnaires. The results were subjected to a multivariate analysis in order to find the major factors associated with various upper-body muscular problems. Several such factors were identified for each investigated type of musculoskeletal problem. Some were related to the individual: age, gender, woman with children at home, use of spectacles, smoking, stomach-related stress reactions, and negative affectivity. Organizational variables of importance were opportunities for flexible rest breaks, extreme peer contacts, task flexibility, and overtime. Identified ergonomic variables were static work posture, hand position, use of lower arm support, repeated work movements, and keyboard or VDT vertical position.