On-line strategies for determining trace levels of nitroaromatic explosives and related compounds in water

We report the development and tests of several systems for the simultaneous determination of 18 energetic compounds and related congeners in untreated water samples. In these systems a Restricted Access Material trap or liquid-chromatography precolumn (with a C(18) or porous graphitic carbon, PGC, stationary phase) followed by a PGC analytical column are used for sample clean-up, enrichment and separation of the trace level analytes, which are then analyzed by mass spectrometry (MS). The relative merits of two MS ionization interfaces (atmospheric pressure chemical ionization, APCI, and atmospheric pressure photoionization, APPI) were also compared for the MS identification and quantification of these analytes. APCI was found to be superior in cases where both alternatives are applicable. A major drawback when applying APPI is that no signal is obtained for the cyclic nitramines and nitrate esters. Using APCI, a wide spectrum of unstable compounds can be determined in a single analysis, and the feasibility of using large volume samples (up to 100 mL) in combination with the sensitivity of the MS detection system provide method detection limits ranging from 2.5 pg/mL (for 2,4-dinitrotoluene and 2,6-diamino-6-nitrotoluene) to 563 pg/mL (for pentaerythritol tetranitrate, PETN), with repeatability ranging from 2 to 7%. Other chemometric parameters such as robustness, selectivity, repeatability, and intermediate precision were also evaluated in the validation of the extraction methods for use in water analysis. Tests with untreated groundwater and drinking water samples, spiked with 20 ng of the analytes, yielded results similar to those obtained with high purity water samples.

Minimally important differences were estimated for the Functional Assessment of Cancer Therapy–Colorectal (FACT-C) instrument using a combination of distribution- and anchor-based approaches

OBJECTIVE

To estimate minimally important differences (MIDs) on the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) instrument using anchor- and distribution-based methods.

STUDY DESIGN AND SETTING

Preliminary MIDs were generated for FACT-C scores based on published results for two samples (n = 60 and n = 63) from the FACT-C validation study. Preliminary MIDs were confirmed using data from a Phase II randomized controlled clinical trial (n = 104) and a population-based observational study (n = 568). MIDs were estimated for the colorectal cancer subscale (CCS); the FACT-C Trial Outcome Index (TOI-C), which is the sum of the CCS, physical well-being, and functional well-being subscales; and the FACT-C total score. Both cross-sectional and longitudinal analyses were used.

RESULTS

MIDs were stable across the different patient samples. The recommended MIDs ranged from 2 to 3 points for the CCS, 4 to 6 points for the TOI-C, and 5 to 8 points for the FACT-C total score.

CONCLUSIONS

MIDs can enhance the interpretability of FACT-C scores, and they can be used to provide a basis for sample size estimation and to determine clinical benefit in combination with other measures of efficacy. General guidelines for estimating MIDs for other FACT instruments are suggested.

Cooperative effects by the initiation codon and its flanking regions on translation initiation

The purine-rich Shine-Dalgarno (SD) sequence located a few bases upstream of the mRNA initiation codon supports translation initiation by complementary binding to the anti-SD in the 16S rRNA, close to its 3' end. AUG is the canonical initiation codon but the weaker UUG and GUG codons are also used for a minority of genes. The codon sequence of the downstream region (DR), including the +2 codon immediately following the initiation codon, is also important for initiation efficiency. We have studied the interplay between these three initiation determinants on gene expression in growing Escherichia coli. One optimal SD sequence (SD(+)) and one lacking any apparent complementarity to the anti-SD in 16S rRNA (SD(-)) were analyzed. The SD(+) and DR sequences affected initiation in a synergistic manner and large differences in the effects were found. The gene expression level associated with the most efficient of these DRs together with SD(-) was comparable to that of other DRs together with SD(+). The otherwise weak initiation codon UUG, but not GUG, was comparable with AUG in strength, if placed in the context of two of the DRs. The +2 codon was one, but not the only, determinant for this unexpectedly high efficiency of UUG.

Phase Ib trial of intravenous recombinant humanized monoclonal antibody to vascular endothelial growth factor in combination with chemotherapy in patients with advanced cancer: pharmacologic and long-term safety data

PURPOSE

Tumor angiogenesis mediated by vascular endothelial growth factor (VEGF) is inhibited by the recombinant humanized (rhu) monoclonal antibody (MAb) rhuMAbVEGF, which has synergy with chemotherapy in animal models. The present study was designed to assess the safety and pharmacokinetics of weekly intravenous (IV) rhuMAbVEGF with one of three standard chemotherapy regimens.

PATIENTS AND METHODS

Twelve adult patients were enrolled four on each combination. rhuMAbVEGF, 3 mg/kg IV, was administered weekly for 8 weeks with (1) doxorubicin 50 mg/m(2) every 4 weeks; (2) carboplatin at area under the curve of 6 plus paclitaxel 175 mg/m(2) every 4 weeks; and (3) fluorouracil (5-FU) 500 mg/m(2) with leucovorin 20 mg/m(2) weekly, weeks 1 to 6 every 8 weeks.

RESULTS

The median number of rhuMAbVEGF doses delivered was eight (range, four to eight doses). Grade 3 toxicities were diarrhea (one 5-FU patient), thrombocytopenia (two patients on carboplatin plus paclitaxel), and leukopenia (one patient on carboplatin plus paclitaxel). These toxicities were likely attributable to the chemotherapy component of the regimen. The mean (+/- SD) peak serum level of rhuMAbVEGF was 167 +/- 46 microg/mL, and the mean terminal half-life was 13 days. Total (free plus bound) serum VEGF levels increased from 51 +/- 39 pg/mL (day 0) to 211 +/- 112 (day 49) pg/mL. Three responding patients continued treatment with rhuMAbVEGF and chemotherapy, receiving the equivalent of 36, 20, and 40 total rhuMAbVEGF doses with no cumulative or late toxicities.

CONCLUSION

rhuMAbVEGF can be safely combined with chemotherapy at doses associated with VEGF blockade and without apparent synergistic toxicity. Its contribution to the treatment of advanced solid tumors should be evaluated in randomized treatment trials.

Phase I safety and pharmacokinetic study of recombinant human anti-vascular endothelial growth factor in patients with advanced cancer

PURPOSE

We investigated the safety and pharmacokinetics of a recombinant human monoclonal antibody to vascular endothelial growth factor (rhuMAb VEGF) in patients with cancer.

PATIENTS AND METHODS

Cohorts of patients with metastatic cancer having failed prior therapy entered a phase I trial of rhuMAb VEGF administered by a 90-minute intravenous infusion at doses from 0.1 to 10.0 mg/kg on days 0, 28, 35, and 42. Patients underwent pharmacokinetic sampling on day 0 and had serum samples obtained during the subsequent 28 days. Response assessment was carried out on days 49 and 72.

RESULTS

Twenty-five patients with a median Eastern Cooperative Oncology Group performance status of 0 were accrued. There were no grade III or IV adverse events definitely related to the antibody. There were three episodes of tumor-related bleeding. Infusions of rhuMAb VEGF were well tolerated without significant toxicity. Grades I and II adverse events possibly or probably related to study drug included asthenia, headache, and nausea. Pharmacokinetics revealed a linear profile with a half-life of 21 days. There were no objective responses, though 12 patients experienced stable disease over the duration of the study.

CONCLUSION

rhuMAb VEGF was safely administered without dose-limiting toxicity at doses ranging up to 10 mg/kg. Multiple doses of rhuMAb VEGF were well tolerated, and pharmacokinetic studies indicate that doses of > or = 0.3 mg/kg have a half-life similar to that of other humanized antibodies. Subsequent trials will explore rhuMAb VEGF alone and in combination chemotherapy.

Fusion protein approach to improve the crystal quality of cytochrome bo(3) ubiquinol oxidase from Escherichia coli

Crystals of cytochrome bo(3) ubiquinol oxidase from E. coli diffract X-rays to 3.5 A and the structure determination is in progress. The limiting factor to the elucidation of the structural detail is the quality of the crystals; the diffraction spots from the crystals are diffused which leads to difficulties in processing the data beyond 4.0 A. Weak protein-protein contacts within the crystal lattice is assumed to be the cause of this problem. To improve these contacts, we have introduced protein Z to the C-terminal end of the subunit IV of cytochrome bo(3) and expressed both proteins as a single fusion. We have successfully obtained crystals of this fusion protein. The spot shape problem has clearly been solved in the crystals of the fusion protein although further optimization is necessary to obtain higher resolution. We also discuss the potential applications of this approach to the crystallization of membrane proteins in general.

Structure of a combination of Functional Independence Measure and Instrumental Activity Measure items in community-living persons: a study of individuals with cerebral palsy and spina bifida

OBJECTIVE

To analyze the structure of a combination of physical items from the Functional Independence Measure (FIM) and seven instrumental activity items using ratings of dependence and perceived difficulty.

DESIGN

Disability in terms of dependence and subject's perceived difficulty was studied in patients with cerebral palsy (CP) and spina bifida (SB). Rasch analysis was used to construct calibrated linear measure and to identify suitable models with respect to rating steps.

SETTING

Interviews were performed at home with patients from an outpatient university rehabilitation unit for young disabled persons.

PATIENTS

Fifty-three CP and 20 SB patients (including 5 with other early acquired spinal cord lesions), 20 to 39 years of age, participated and represented 62% and 80%, respectively, of available patients. All had fulfilled an elementary school program.

RESULTS

The best scoring model using Rasch analysis was achieved using 5 levels for dependence and 4 levels for perceived difficulty. Hierarchic orders for all items are presented. The FIM items Bowel and Bladder showed different characteristics in the two groups of patients, especially for perceived difficulty, and were excluded in the joint calibrations. There was close overall agreement between the ratings of dependence and perceived difficulty. Person measure values from the Rasch analyses were separated between wheelchair users and walkers.

CONCLUSION

The combination of physical items from FIM and instrumental activity measure (IAM) are useful for disability assessment in community-living persons and should be further studied in other impairment groups.

Translocation and processing of various human parathyroid hormone peptides in Escherichia coli are differentially affected by protein-A-signal-sequence mutations

Two staphylococcal protein-A signal sequences were constructed and tested for function in Escherichia coli, after being linked to human parathyroid hormone (hPTH) cDNAS representing the intact form (1-84 amino acids) and two N-terminal (1-37 and 1-7 amino acids) peptides. One signal sequence was identical to the wild type, and the other signal contained a deletion of 12 bp at the 3' end. The truncated hPTH cDNAs were fused at their 3' ends to IgG-binding domains (ZZ) derived from protein A in order to facilitate purification and characterization. The expression plasmid pSPTH, containing the wild-type signal sequence, secreted efficiently the intact recombinant hPTH (1-84) into the medium. Plasmids containing the truncated hPTH genes after the wild-type signal, gave rise to hPTH-ZZ hybrid proteins which were correctly processed at the N-terminal, but the major fractions appeared in the periplasmic compartment. In contrast, the plasmid pS'PTH which harboured the 4-amino-acid signal deletion did not promote a uniform secretion of intact hPTH (1-84) to the medium, but released a non-processed form both into the periplasmic compartment and to the medium. The related plasmids pS'PTH37ZZ and pS'PTH7ZZ with the mutated signal sequence gave rise to small or trace amounts of unprocessed forms of fusion proteins in the medium and periplasm, thus the secretion competence was markedly reduced. Thus, for correct N-terminal processing, we conclude that the amino acid sequence in the signal adjacent to the expressed protein, is a key determinant. However, release into the medium or periplasmic space appeared to be dependent also on protein folding, irrespective of signal-sequence cleavage. Furthermore, we observed that the peptides with the wild-type signal sequence and correct N-terminal processing, were the only forms that showed internal cleavage of hPTH. Uncleaved signals may contribute to folding characteristics of the ensuing protein and e.g., prevent internal proteolysis.

Co-existing structures of an mRNA stability determinant. The 5' region of the Escherichia coli and Serratia marcescens ompA mRNA

The structure of untranslated regions of mRNA is thought to play a key role in the degradation of mRNAs by specific RNases. As a model system, in vitro transcripts of the stability determining 5' non-coding region of bacterial ompA mRNA were investigated by calculation of secondary structure models and by experiments applying the temperature-gradient gel electrophoresis (TGGE). For the theoretical prediction of secondary structures an algorithm was used, which yields the structure of lowest free energy as well as a large set of suboptimal structures. Three structures were predicted to co-exist in similar concentrations under native conditions. They denature in a low temperature transition leading to a unique structure which denatures in a high temperature transition. The prediction of three structures and two transitions could be confirmed experimentally by TGGE. Due to the use of transcripts of different length the conformational transitions could be attributed to distinct parts of the molecules. A pseudoknot structural motif was predicted theoretically, but could not be confirmed experimentally. Comparing ompA transcripts of E. coli and S. marcescens, a conservation of structural features could be shown in spite of a sequence homology of only 63%. Regarding the sequential folding of the transcript after synthesis, a metastable structure is formed first and is converted slowly into structures of lower free energy. The biological implications for in vivo degradation are discussed.

Fusions to the 5' end of a gene encoding a two-domain analogue of staphylococcal protein A

A novel gene fusion system has been constructed for fusions to the 5' end of gene zz, encoding a two-domain analogue of staphylococcal protein A designated ZZ. Four different genes were fused to the 5' end of zz, and their gene products were analyzed. One of the genes encodes a protein located intracellularly in Escherichia coli and the other three genes encode gene products destined for secretion across the cytoplasmic membrane by the presence of an amino terminal signal sequence. After production in E. coli, the fusion proteins were purified in a single step by IgG-affinity chromatography. The purified ZZ fusions could be used directly for amino terminal sequencing to confirm the start of translation of the intracellular product and the processing of the signal peptide of the translocated products. This is the first example of ZZ fusions to the C-terminus of gene products. To simplify the general use of fusions to the 5' end of zz, a new plasmid vector was constructed containing a multi restriction enzyme cloning linker and the lacZ' gene which enables screening for production in alpha-complementing supE strains of E. coli on indicator plates.

A method for the evaluation of the efficiency of signal sequences for secretion and correct N-terminal processing of human parathyroid hormone produced in Escherichia coli

Expression plasmids have been constructed for evaluation of different signal sequences for secretion and correct amino terminal processing of foreign proteins expressed in Escherichia coli. cDNA representing the N-terminal region (1-37) of human parathyroid hormone was inserted between DNA coding for two different forms of the signal sequence and two IgG binding domains (ZZ) derived from Staphylococcal protein A. The expression products were secreted to the periplasm and even to the growth medium and were easily purified by affinity chromatography using the ZZ part as a specific handle. Further analyses showed that the expression products were correctly processed to the mature protein hPTH(1-37)ZZ in a construct where the wild type signal sequence of Staphylococcus protein A was used. When a mutated signal sequence which lacks the normal cleavage site was employed, the fusion protein was not cleaved. Since signal sequences seem to be processed in the correct way in this system, we conclude that the general design of this type of expression vector is well suited for studying the N-terminal processing and secretion of heterologous proteins in E. coli.

An evaluation of different enzymatic cleavage methods for recombinant fusion proteins, applied on des(1-3)insulin-like growth factor I

Different enzymatic methods for cleavage of recombinant fusion proteins were compared. To find an efficient cleavage method, five different fusion proteins were produced. The fusion proteins differed only in the linker region between the fusion partner and the desired product, human des(1-3)insulin-like growth factor I. A cleavage study was performed with enterokinase, plasmin, thrombin, urokinase, and recombinant H64A subtilisin. Significant cleavage was obtained using thrombin, H64A subtilisin, and enterokinase. Thrombin cleavage was studied on a larger scale and des(1-3)IGF-I was recovered at a final yield of 3 mg/L growth medium. Thrombin and enterokinase were also studied as immobilized proteases and they cleaved the fusion proteins with retained activity. To further improve thrombin cleavage, a continuous reactor was constructed, consisting of a closed system with a thrombin column and an ion exchange column in series. Here, the fusion protein circulated while free des(1-3)IGF-I was bound to the ion exchange column after release from the fusion protein. In the reactor, thrombin was as efficient as the free enzyme but gave a diminished rate of product degradation.

Thrombin and H64A subtilisin cleavage of fusion proteins for preparation of human recombinant parathyroid hormone

Human parathyroid hormone, hPTH, an 84 amino acid polypeptide, was produced intracellularly in Escherichia coli as a fusion protein, linked to the C-terminus of a 15 kD IgG-binding protein. Approximately 100 mg fusion protein was obtained per liter fermentation medium. To test the efficiency of two alternative enzymatic cleavage methods, two fusion proteins differing only in the linker region were constructed. Cleavage of a Phe-Phe-Pro-Arg linker was obtained with bovine thrombin and cleavage of a Phe-Ala-His-Tyr linker with recombinant H64A subtilisin. Both enzymes yielded the correct N-terminus and cleaved their respective linkers quantitatively, although additional internal cleavage sites in hPTH were detected and characterized. The linker cleavage conditions were optimized and hPTH was purified to homogeneity. Thrombin cleavage resulted in a final yield of 5 mg hPTH/L, while H64A subtilisin cleavage was more specific and gave 8 mg/L. The purified recombinant product was identical to native hPTH and exhibited full biological activity in an adenylate cyclase assay.

A recombinant Escherichia coli heat-stable enterotoxin (STa) fusion protein eliciting anti-STa neutralizing antibodies

A recombinant fusion protein consisting of native Escherichia coli heat-stable enterotoxin (STa) and a dimer of a synthetic IgG-binding fragment (ZZ), derived from Staphylococcus aureus protein A was produced in E. coli. The fusion protein (ZZSTa) was secreted in large quantities into the growth medium and recovered by affinity chromatography on IgG-Sepharose. Rabbits immunized with the fusion protein responded by producing high serum levels of anti-STa antibodies that also effectively neutralized STa toxicity in infant mice. The fusion peptide ZZSTa had a substantially decreased toxicity as compared with native STa. A polymeric form of ZZSTa separated by size fractionation was about 100 times less toxic than the monomeric fusion protein, yet both forms had the same capacity to induce neutralizing antibodies. This suggests that modified non-toxic forms of ZZSTa with retained immunogenicity may be produced and tested for their usefulness as functional components in a vaccine against diarrhoea caused by enterotoxigenic E. coli.

Characterization of an extended form of recombinant human insulin-like growth factor II

To investigate the biological role of variants of human insulin-like growth factor II (IGF-II), an extended form designated IGF-IIE21, with a molecular mass of 9.8 kDa, was produced in Escherichia coli as a stable and soluble secreted fusion protein. After site-specific cleavage of the affinity purified fusion protein, followed by purification using ion exchange and reversed phase chromatography, it could be demonstrated that IGF-IIE21 and IGF-II have similar or identical activities according to radioimmunoassay and radioreceptor assay. However, IGF-IIE21 showed only 1% growth promotion activity as compared with IGF-II in a clonal expansion assay using human K562 cells which lacks IGF-I receptors. These results suggest that this extended variant of IGF-II can bind to the receptor but has limited growth promoting activity.

Purification and characterization of recombinant human insulin-like growth factor II (IGF-II) expressed as a secreted fusion protein in Escherichia coli

Human insulin-like growth factor II (IGF-II) was produced in an Escherichia coli ompT strain as a 22.5-kDa fusion protein. IGF-II was fused to the carboxy-terminal of a synthetic 15-kDa IgG-binding protein, originating from staphylococcal protein A, via a unique methionine linker. During fermentation, the fusion protein was exported to the growth medium at levels exceeding 900 mg/liter and subsequently affinity purified on IgG Sepharose followed by ion exchange on S Sepharose. After chemical cleavage with CNBr, yielding an authentic IGF-II molecule, the recombinant IGF-II was purified to homogeneity by a two step procedure involving ion-exchange and reverse-phase HPLC. A substantial fraction of the secreted protein was found to be biologically active, eliminating the need for complex refolding procedures. The yield of highly purified and biologically active IGF-II was 5-7 mg/liter of fermenter broth. The IGF-II produced by this method displayed biochemical, immunological, receptor binding, and biological activity properties equal to those of native IGF-II isolated from human serum.

Synthesis and secretion of a fibrinolytically active tissue-type plasminogen activator variant in Escherichia coli

A gene encoding a variant (lacking amino acids 6-173) of human tissue-type plasminogen activator (t-PA), consisting only of the second kringle domain (K2) and the serine protease domain (P), was fused to a DNA segment coding for the signal peptide of staphylococcal protein A and a synthetic gene coding for a protein with ability to bind immunoglobulin G (IgG). The fusion protein which was synthesized in Escherichia coli and secreted into the growth medium, was found to be fibrinolytically active. Purification of the fusion protein was performed in a single step by affinity chromatography with immobilized IgG. Enzymatically active K2P was liberated from the fusion protein by cleavage at a unique Asn-Gly dipeptide sequence using hydroxylamine. These results demonstrate that a variant of human t-PA can be synthesized and secreted by E. coli as a fibrinolytically active fusion protein, which upon specific cleavage yields an active variant t-PA of the expected size.

Human immunodeficiency viral protease is catalytically active as a fusion protein: characterization of the fusion and native enzymes produced in Escherichia coli

Processing of the gag and pol gene precursor proteins of retroviruses is essential for the production of mature infectious virions. The processing is directed by a viral protease that itself is part of these precursors and is presumed to cleave itself autocatalytically. To facilitate study of this process, the protease was produced as a fusion protein in Escherichia coli. In this construct, the 10,793-Da protease was preceeded by two copies of a modified IgG binding domain derived from protein A. The IgG binding domain was linked to the protease by an Asp-Pro peptide bond which could not be cleaved by the viral protease. A dimer of the 25,400-Da fusion protein was catalytically active, specifically cleaving a substrate peptide at the correct Tyr-Pro bond. Thus, the fusion protein could serve as a model of the viral gag-pol polyprotein. The finding that the fusion protein was catalytically active supports the suggestion that a gag-pol dimer can initiate a proteolytic cascade after budding of the immature virus. The fusion protein also provided a source of authentic protease. The protease was released from the fusion construct by incubation with formic acid, cleaving the Asp-Pro linkage which had been inserted between the IgG binding domain and the protease.

Enhanced immunogenicity of recombinant peptide fusions containing multiple copies of a heterologous T helper epitope

We have examined the immune response against the nonimmunogenic heat-stable enterotoxin (STa) of enterotoxigenic Escherichia coli using recombinant fusion proteins containing the STa-peptide linked to an IgG-binding analogue of protein A and varying numbers of the T helper epitope 323-339 from ovalbumin (ova). By immunization of inbred strains of mice with a series of STa fusion proteins, containing up to four copies of ova tandemly multiplied, we demonstrated that the anti-STa antibody response is controlled by ova-specific T helper cells in a genetically restricted manner. In the responding mouse strains (2 out of 3 tested), the level of antibody production was increased by addition of multiple ova epitopes, the anti-STa response being considerably higher to fusion proteins containing four than one or two ova epitopes.

Three human interferon-alpha 2 subvariants disclose structural and functional differences

The human interferon-alpha 2 subvariants 2a, 2b and 2c differ by only one or two amino acids at positions 23 and/or 34 of the mature protein. In this study, the coding regions of the three interferon-alpha 2 subvariants were derived from the cDNA of interferon-alpha 2c by site-directed in vitro mutagenesis. The interferon-alpha subvariants were synthesized using the same Escherichia coli strain for production and were subsequently purified. Comparative studies revealed that they differ significantly in their biological and antigenic properties. Therefore, amino acid positions 23 and 34 seem to be crucial for structure/function of human interferon-alpha. Furthermore, the study points to the importance of defining, whether such minor structural variants of naturally occurring polypeptides represent functional variants.

Differential stability of recombinant human insulin-like growth factor II in Escherichia coli and Staphylococcus aureus

Recombinant human insulin-like growth factor II (IGF-II), produced as a soluble extracellular fusion protein, was shown to be proteolytically degraded in Escherichia coli. In contrast, the fusion protein secreted from Staphylococcus aureus was stable and the full length product could be recovered by affinity chromatography. After site specific cleavage of the fusion protein, soluble IGF-II with biological activity was obtained without refolding procedures. These results demonstrate that a eukaryotic protein unstable in E. coli can be stabilized by expression in a Gram positive host. The full-length fusion protein from S. aureus was used to characterize the protease responsible for the degradation in E. coli. Biochemical and genetic analysis suggests a specific degradation by the outer membrane protease (OmpT).

Expression and characterization of a recombinant human parathyroid hormone secreted by Escherichia coli employing the staphylococcal protein A promoter and signal sequence

Human parathyroid hormone (hPTH) is a peptide hormone consisting of 84 amino acids (hPTH(1-84)). Employing the promoter and signal sequence of Staphylococcus aureus-protein A we have expressed hPTH in Escherichia coli. The expressed proteins are excreted to the growth medium, allowing for rapid and easy purification of the desired products. By amino acid sequence analysis and mass spectrometry, we have shown that the major excreted product is correctly processed human identical hPTH(1-84). The purified recombinant hPTH(1-84) stimulates adenylate cyclase activity in rat osteosarcoma cell membranes to exactly the same extent as synthetic parathyroid hormone standards, indicating that the recombinant product has full biological activity.

Rhizobium meliloti anthranilate synthase gene: cloning, sequence, and expression in Escherichia coli

We determined the DNA sequence of the Rhizobium meliloti gene encoding anthranilate synthase, the first enzyme of the tryptophan pathway. Sequences similar to those seen for the two subunits of the enzyme as found in all other procaryotic species studied are present in a single open reading frame of 729 codons. This apparent gene fusion joins the C terminus of the large subunit (TrpE) to the N terminus of the small subunit (TrpG) through a short connecting segment. We designate the fused gene trpE(G). The gene is flanked by a typical rho-independent terminator at the 3' end and a complex regulatory region at the 5' end resembling those of operons under transcriptional attenuation control. The location of the promoter was determined by S1 nuclease protection, using Rhizobium mRNA. Although this promoter was inactive in Escherichia coli, mutations eliciting activity were easily obtained. One of these was a C----T change at position -9 in the -10 region. The +1 position of the mRNA is the first base of the initiation codon of the leader peptide, implying that unlike trpE(G), which has a normal Shine-Dalgarno sequence, the leader peptide gene lacks a ribosome-binding site.

Dual affinity fusion approach and its use to express recombinant human insulin-like growth factor II

A dual affinity fusion concept has been developed in which the gene encoding the desired product is fused between two flanking heterologous genes encoding IgG- and albumin-binding domains. Using sequential IgG and serum albumin affinity chromatography, a full-length tripartite fusion protein is obtained. This approach was used to recover a full-length fusion product in Escherichia coli containing the human insulin-like growth factor II (IGF-II). Surprisingly, the recombinant IGF-II showed increased stability against proteolytic degradation in E. coli when produced as a dual affinity fusion protein, as compared to an N-terminal fusion protein. After site-specific cleavage of the tripartite fusion protein, IGF-II molecules with immunological and receptor binding activity were obtained without renaturation steps. The results demonstrate that proteins can fold into biologically active structures, even if provided with large flanking heterologous protein domains. The concept was further used to characterize the specific degradation of recombinant IGF-II in this heterologous host.

A comparison of the Glasgow Coma Scale and the Reaction Level Scale (RLS85)

The Glasgow Coma Scale (GCS) and the Reaction Level Scale (RLS85) were compared for rating neurosurgical patients in regard to ranking order of deficit severity, interobserver variability, and coverage for relevant factors. Four physicians, four registered nurses, and four assistant nurses performed 72 pairwise ratings on 47 neurosurgical patients. The rank correlation between the GCS sum score and the RLS85 was -0.94, suggesting the same ranking order of severity and indicating that the underlying concepts of somnolence, delirium, and motor responses in coma are evaluated in the same way. By the sign test, the RLS85 was shown to have better interobserver agreement than the GCS sum score and the eye-motor-verbal (EMV) profile. The interobserver grading disagreements in both scales were distributed over the entire range of responsiveness, and for the GCS sum score they were slanted to combined segments 9 to 15. The RLS85 showed full coverage of relevant factors, while 43 (60%) of the 72 test occasions in the GCS sum score and the EMV profiles showed untestable features, most often because of patient intubation. The pseudoscore (that is, the choice of value given to untestable features) affects interobserver agreement as well as the estimated overall patient responsiveness in the GCS sum score. Assessment by the order of applying the scales showed a significant effect on the GCS eye-opening scale (p = 0.01) and the GCS sum score (p = 0.03), indicating a sensitivity to environmental stimuli unrelated to the patient's status. This study demonstrates that basically the same information as that found in the separate eye, motor, and verbal scales of the GCS can be combined directly into the RLS85, which has better interobserver agreement and better coverage than the GCS sum score.

Current reporting of responsiveness in acute cerebral disorders. A survey of the neurosurgical literature

One hundred sixty-six papers published in seven neurosurgical journals from 1983 through 1985 have been surveyed to determine the methods used for assessment of overall patient responsiveness in acute cerebral disorders (coma grading). Fifty-one different coma scales or modifications were found. The Glasgow Coma Scale (GCS) sum score (that is, the sum of the scores of the individual eye, verbal, and motor scales) dominated (54%), and was used in 73 (76%) of 96 of the head-injury studies; in 56 (77%) of these 73 studies it was the single method of grading neurological status. The GCS sum score was used in 16 (23%) of 70 studies in patients with other etiologies. The Hunt and Hess scale was used in 26 (57%) of 46 reports of patients with subarachnoid hemorrhage. In 31 (55%) of the 56 studies of head injuries using the GCS alone, it was not obvious if the 12- or 13-grade scale was used. In 13 studies (23%) no reference to methodological investigations was made. In 44 papers (79%) the handling of untestable features, such as intubation or swollen eyes, was not reported. In the 56 studies using the GCS alone, coma was defined in many different ways and in 22 studies the definition of coma was not specified. In 63% of reports, the GCS sum score scale was combined in one to five groups of scores and this was done in 32 different ways. No information was available to describe the procedure of data aggregation or the reliability of the 13-grade GCS sum score. The lack of standardization makes it unnecessarily difficult to perform valid comparisons between different series of patients. Since the GCS sum score is the most widely used scale, it is suggested that the reporting of the GCS sum score should be standardized regarding pseudoscoring, coma definition, and use of combined scores. Further studies on the reliability of the GCS sum score are needed.

Assessment of responsiveness in acute cerebral disorders. A multicentre study on the reaction level scale (RLS 85)

A new scale for assessment of overall responsiveness, the Reaction Level Scale (RLS 85), which has been shown to have better reliability than the Glasgow Coma Scale (GCS), has been tested in four neurosurgical departments regarding inter-observer agreement and coverage i.e. the proportion of patients that could be assessed by the scale. In a carefully designed study 51 observers pairwise performed 164 tests on 88 patients. Reliability was studied by the Kappa method, which is defined as inter-observer agreement corrected for agreement by chance. The inter-observer agreement measured as overall Kappa was good (K = 0.69 +/- 0.05) and there were no significant differences between the departments, professional categories or aetiologies. Regarding the separate RLS 85 levels the Kappa values were above 0.65, except for withdrawing (K = 0.51) and flexor responses (K = 0.55). There was good inter-observer agreement on coma (K = 0.71). In conclusion, the RLS 85 proved to be easily learnt, it showed full coverage without pseudoscoring, and it was used in a consistent way by doctors, nurses and assistant nurses of four different neurosurgical departments in two Scandinavian countries.

The Reaction Level Scale (RLS85). Manual and guidelines

The Reaction Level Scale (RLS85) is a "coma scale" for the direct assessment of overall reaction level in patients with acute brain disorders. It is devised for reliable use even in the management of patients who are difficult to assess, such as intubated patients and patients with swollen eyelids. We here present the manual of the RLS85 and the guidelines for its use. The underlying concepts as well as limitations are outlined. Condensed information of known reliability and validity is presented. A training scheme for presumed observers (doctors, nurses and assistant nurses) is outlined. It is suggested that users of the RLS85 refer to these guidelines and in scientific reports clearly state any deviations from this present manual in order to facilitate valid comparisons between different studies and different groups of patients.

Expression of human insulin-like growth factor I in bacteria: use of optimized gene fusion vectors to facilitate protein purification

Several fusions between the gene for human insulin-like growth factor I (IGF-I) and the genes for different IgG-binding fragments of staphylococcal protein A were assembled and compared regarding expression, secretion, and purification of the peptide hormone. After IgG affinity purification of the fusion proteins from the growth medium of Staphylococcus aureus or Escherichia coli, native IGF-I was released by cleavage of an Asn-Gly peptide bond with hydroxylamine. An optimized expression system based on a modified synthetic IgG-binding domain (z), resistant to hydroxylamine, gave the highest yield of fusion protein. After cleavage, the hormone could be separated from the IgG-binding moiety and from noncleaved fusion protein by a second passage through the IgG affinity column. The biological activity and the purity of the IGF-I obtained were confirmed by a radioreceptor assay, N-terminal sequence analysis, polyacrylamide gel electrophoresis, isoelectric focusing, and high-performance liquid chromatography.

Fibrinopeptide A and fibrinogen fragment B beta 15-42 and their relation to the operative trauma and post-operative thromboembolism in neurosurgical patients

In an earlier study on post-operative thromboembolism in neurosurgery the incidence of deep vein thromboses (DVT) diagnosed by the fibrinogen uptake test and phlebography was reduced to the same extent by two different prophylactic methods (low dose heparin or calf muscle stimulation + dextran). However, patients with lower limb paresis due to a brain lesion experienced relatively often a less successful prophylaxis compared to patients with spinal lesions. There are few reports on successful clinical methods for haematological screening of post-operative DVT. The aim of this study was to examine possible haematological indicators for post-operative thromboembolism and secondarily to elucidate whether there exist some special coagulatory or fibrinolytic characteristics in patients who had been operated upon for brain lesions. We have studied two specific coagulatory factors (FPA reflecting thrombin generation and B beta 15-42 reflecting plasmin activity) in connection with neurosurgical operations. Patients in the above-mentioned study on post-operative DVT operated upon for malignant cerebral tumours or intracranial vascular disease exhibited post-operatively higher values for FPA compared to other neurosurgical diagnoses. B beta 15-42 was higher in the malignant tumour group and almost significantly higher in the intracranial vascular group (p less than 0.065). These differences could not be ascribed to the occurrence of DVT. Another 15 patients divided into a minor and a major lesion group were investigated with determination of both parameters pre- and post-operatively. Concerning FPA an increase was noticed post-operatively compared to pre-operatively in the major lesion group.(ABSTRACT TRUNCATED AT 250 WORDS)

A synthetic IgG-binding domain based on staphylococcal protein A

A synthetic IgG-binding domain based on staphylococcal protein A was designed with the aid of sequence comparisons and computer graphic analysis. A strategy, utilizing non-palindromic restriction sites, was used to overcome the difficulties of introducing site-specific changes into the repetitive gene. A single mutagenized gene fragment was polymerized to different multiplicities, and the different gene products were expressed in Escherichia coli. Using this scheme, protein A-like proteins composed of different numbers of IgG-binding domains were produced. These domains were changed to lack asparagine--glycine dipeptide sequences as well as methionine residues and are thus, in contrast to native protein A, resistant to treatment with hydroxylamine and cyanogen bromide.

A gene fusion system for generating antibodies against short peptides

A novel method to obtain specific antibodies against short peptides is described, involving synthesis of the corresponding oligodeoxynucleotides followed by cloning into a new set of fusion vectors, pEZZ8 and pEZZ18, based on two synthetic IgG-binding domains (ZZ) of Staphylococcus aureus protein A. The soluble gene fusion product thus obtained, can be collected from the culture medium of Escherichia coli and rapidly recovered in a one-step procedure by IgG affinity chromatography. The system was used to express a fusion protein consisting of the two Z fragments and the C-terminal part [amino acids (aa) 57-70] of human insulin-like growth factor I (IGF-I). This 16-kDa protein was purified by affinity chromatography on IgG Sepharose and antibodies were raised in rabbits. The fusion protein elicited peptide-specific antibodies, as measured by solid-phase radioimmuno assay and Western blotting, reactive with both synthetic C-terminal peptide and the native human IGF-I protein. The results suggests that the gene fusion system can be used for efficient antibody production against short peptides encoded by synthetic oligodeoxynucleotides.

On a free autologous graft of the greater omentum for spinal CSF drainage

A pedicular flap of the greater omentum can after transposition through the posterior abdominal wall to the lumbar subarachnoid space resorb cerebrospinal fluid (CSF), according to earlier studies. The present study investigates the basic prerequisites in rats and cats for a simplification of the method, utilizing a free omental graft transplanted to the lumbar or cervical region, in contact with neighbouring sacrospinal muscles. It is concluded from long term studies that the free omental graft "survives" and preserves its histological characteristics by revascularization between muscle and omentum, indicating a useful resorptive function.