De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin

BACKGROUND

Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk.

METHODS

From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials.

RESULTS

De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis.

CONCLUSIONS

The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

Inhibition of cathepsin G by 4H-3,1-benzoxazin-4-ones

A series of 4H-3,1-benzoxazin-4-ones is reported that inhibit the serine proteases human cathepsin G and bovine chymotrypsin. The synthesis and kinetic parameters of the alkaline hydrolysis is described. These compounds act as acyl-enzyme inhibitors of both enzymes. The reaction of cathepsin G with 2-benzylamino-4H-3,1-benzoxazin-4-one (20) was studied in detail. A partition in deacylation of the initially formed acyl-enzyme was observed, leading to the formation of 2-(3-benzylureido)benzoic acid (26) and 3-benzylquinazoline-2,4-(1H,3H)-dione (27). A 6-methyl substitution strongly increased the acylation rate of both proteases. Introduction of an aryl moiety into the 2-substituent led to compounds with Ki values towards cathepsin G in the nanomolar range. Their inhibitory potency is stronger than that of other synthetic inhibitors of cathepsin G.

De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin

BACKGROUND

Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk.

METHODS

From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials.

RESULTS

De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis.

CONCLUSIONS

The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

Characterization of porin from Roseobacter denitrificans

Porin from Roseobacter denitrificans was isolated and purified to homogeneity. The pore characteristics from this marine bacterium were compared to those of its phylogenetically closely related freshwater bacteria Rhodobacter capsulatus, Rhodobacter sphaeroides and Rhodopseudomonas blastica. The porin formed weakly cation-selective, general diffusion pores in lipid bilayer membranes. High transmembrane potentials caused channel closing in steps that were of one or two thirds of the initial on-steps indicating that the porin of R. denitrificans comprised three more or less independent channels similar to PhoE and OmpC of Escherichia coli and the porin of Rhodobacter capsulatus. 37b4 Prediction of the secondary structure of the 36 N-terminal amino acid residues indicated two transmembrane beta-strands similar to those of the porins of Rhodobacter capsulatus 37b4 and Rhodopseudomonas blastica. Differences of the single channel conductivities between the porin of R. denitrificans and those of the related freshwater bacteria show that R. denitrificans evolved porin channels that are well adapted to the marine habitat.

[Pilot study on the prevalence of Ornithobacterium rhinotracheale infections in food chickens in northwest Germany]

Samples of sera from broiler chicken and broiler chicken breeder flocks of North Western Germany were examined for presence of antibodies against Ornithobacterium (O.) rhinotracheale with a self-developed ELISA system. A total of 3600 samples of sera from 190 broiler flocks in 70 different farms were tested. In 332 samples of sera (9.4%) from 25 flocks (13.2%) in 22 farms specific antibodies were detected. Additionally, serum samples from the breeder hens, taken between the 9, and 61, weeks of age were tested. In 28 from 29 flocks (96.6%) specific antibodies were detected using this ELISA-system. First detectable antibodies were found between the 14, and 36, week of age in the parent breeder flocks. These results show that infections with O. rhinotracheale are widely distributed in the parent-breeder chicken broiler flocks. The significance of this bacterium as the cause of respiratory diseases in chickens are discussed.

A prospective randomized trial comparing interleukin-2 receptor antibody versus antithymocyte globulin as part of a quadruple immunosuppressive induction therapy following orthotopic liver transplantation

BACKGROUND

Quadruple immunosuppressive induction therapy has been shown to markedly reduce the incidence of acute rejection episodes without increasing the incidence of infectious complications after liver transplantation. However, the use of polyclonal antibody preparations (e.g. antithymocyte globulin [ATG]) is associated with side effects such as fever and tachycardia. To evaluate the efficacy and the safety of a monoclonal antibody directed against the interleukin-2 receptor (BT563) in comparison with ATG as part of a quadruple induction regimen, a prospective, randomized study was conducted.

METHODS

Eighty consecutive adult recipients of primary orthotopic liver transplants were randomized to receive either BT563 (10 mg/day; days 0-12; n=39) or ATG (5 mg/kg/day; days 0-6; n=41) in addition to the standard immunosuppressive protocol consisting of cyclosporine, and prednisolone, and azathioprine.

RESULTS

Patients treated with BT563 had a significantly lower incidence of steroid-sensitive rejection episodes (3 vs. 11; P<0.025) and also significantly fewer drug-related side effects (4 vs. 18, P<0.038) when compared with patients treated with ATG. The incidence of infectious complications was not different between the two groups. Patient survival did not differ significantly between the two groups (84.6% at 1, 2, and 3 years in the BT563 group and 90.2% at 1 year and 87.8% at 2 and 3 years for the ATG group). Analysis of graft function showed an advantage for the BT563 group in terms of postoperative bilirubin levels. However, no differences were observed in long-term follow-up between the two groups.

CONCLUSIONS

Our results indicate that treatment with anti-interleukin-2 receptor antibody as part of quadruple induction therapy after orthotopic liver transplantation is safe and effective and shows fewer steroid-sensitive rejection episodes as well as fewer side effects when compared with quadruple induction therapy including ATG.

Nitroglycerin versus epoprostenol: effects on hemodynamics, oxygen delivery, and hepatic venous oxygenation after liver transplantation

Our objective was to determine the effects of vasodilatory treatment with epoprostenol (PGI2) and nitroglycerin (NTG) on systemic oxygen delivery index (DO2) and hepatic venous oxygen saturation (SvhO2) after liver transplantation. This prospective study used repeated-measures design. Fifteen adult patients undergoing orthotopic liver transplantation (OLT) were enrolled. Postoperatively, a fiberoptic pulmonary artery catheter was inserted into the right hepatic vein and a timed infusion of PGI2 and NTG was sequentially performed in random order at the following rates: PGI2 at 5 ng/kg/minute and NTG at 0.1 microgram/kg/minute. Each step in each sequence lasted 45 minutes, followed by a control interval of 45 minutes. Measurements were taken at the end of each period when hemodynamic function was stable. Systemic hemodynamics, DO2, oxygen uptake index (VO2), mixed venous oxygen saturation (SvO2), and SvhO2 were assessed. We found that PGI2 induced an increase of cardiac index (+18%, p < .05); DO2 (+16%, p < .05); and SvhO2 (+11%, p < .05). Mean arterial pressure was decreased during PGI2 infusion (-9%, p < .05), as well as during infusion of NTG (-10%, p < .05). NTG significantly decreased DO2 (-6%, p < .05) and SvhO2 (-4%, p < .05). Neither drug affected VO2. We conclude that PGI2 induced vasodilation and increased systemic oxygen delivery in parallel with SvhO2, suggesting a corresponding increase of hepatic oxygen supply. NTG induced systemic vasodilation and significantly impaired hepatic venous oxygen saturation and DO2. Thus, if vasodilatory therapy is indicated in the patient after liver transplantation, PGI2 appears to be better than NTG in improving DO2 without impairing splanchnic oxygenation.

A peptidoglycan binding domain in the porin-associated protein (PAP) of Rhodospirillum rubrum FR1

The porin-associated protein of Rhodospirillum rubrum FR1 was found to contain a peptidoglycan binding motif. A partial fragment of 179 amino acids, obtained by cleavage of PAP with trypsin, Asp-N protease, and CNBr, was sequenced. Substantial sequence homology was found of the C-terminal part (residues 126-179) of porin-associated protein with OmpA, the peptidoglycan-associated lipoprotein of several bacteria, protein F of Pseudomonas aeruginosa, and PIII of Neisseria gonorrhoeae, the latter being also a porin-associated protein. The 179 amino acid fragment comprised about 67% of the mass spectrometrically determined total mass of PAP of 27850 Da.

Incidence and outcome of arterial complications after orthotopic liver transplantation

Arterial complications can be a major factor in morbidity and mortality after orthotopic liver transplantation (OLT), as they may cause graft failure, sepsis and complications of the biliary tract. From September 1988 to December 1994, 571 OLT were performed in 529 patients. The follow-up period ranged from 8 to 83 months. Actuarial 1-, 3- and 5-year survival figures were 91%, 87% and 85%, respectively. In 12 cases (2.1%) complications of the arterial anastomoses were observed. Early arterial complications occurred in eight cases from various causes, while late arterial complications were exclusively thromboses and developed in four patients 8, 12, 26 and 37 months after surgery, respectively. The main clinical course in patients with arterial thromboses was septic cholangitis with destruction of the biliary tree. Although 70% of the grafts with arterial thrombosis were lost, 30% could, at least temporarily, be salvaged by other treatment options. Provided adequate treatment is carried out, arterial complications do not affect overall patient survival.

[Electrophoretic analysis on the proteolytic decomposition of of FSH preparations]

We investigated the influence of some proteolytic enzymes being present in the digestive canal (pepsin, trypsin, chymotrypsin) on the digestion of porcine FSH-samples by electrophoresis. Trypsin and Chymotrypsin digested the 18-kDa-protein much faster than pepsin, whereas a 67-kDa-protein was much faster digested by Pepsin than by Trypsin or Chymotrypsin. The overall proteolytic effect of Chymotrypsin is small compared with Pepsin and Trypsin. A subsequent digestion with Pepsin, Trypsin and Chymotrypsin led to a complete proteolysis of all proteins being present in the sample.

[Cerebral ischemia during implantation of automatic defibrillators]

In order to study the influence of repetitive episodes of ventricular fibrillation (VF) during defibrillator implantation on the electrical activity of the brain, we performed an electroencephalographic (EEG) monitoring during implantation procedure in 18 patients. For defibrillation threshold testing 62 episodes of VF (1-6 episodes per patient) were induced. The mean duration of VF was 20 +/- 12 s; the mean duration of hypotension during an episode (defined as a mean arterial pressure of 50 mm Hg or less) was 33 +/- 16 s. EEG monitoring was performed using the International 10-20 System. The duration of cardiac arrest-related EEG alteration was assessed by an experienced neurologist and could be determined in 41 test-episodes; in 21 episodes analysis was not possible due to poor recordings. Ischemia-related EEG changes started 7.8 +/- 4.6 s after VF induction and lasted 64 +/- 49 s (range, 12-240). The duration of EEG alteration was significantly (p < .001) correlated with the duration of VF episodes (r = .71) and the associated hypotension (r = .82). With regard to patients the duration of ischemia related EEG changes also correlated significantly (p = .001) with the individual cumulative duration of VF (r = .85) and the associated hypotension (r = .88). In females EEG changes lasted longer than in males (p = .03); this finding, however, was only based on 2 women. Other clinical parameters, such as patient age, degree of congestive heart failure, left ventricular ejection fraction, stroke volume and cardiac index, the order of episodes within the testing sequence, and the time interval between episodes did not correlate with the duration of EEG alteration after VF induction. The duration of ischemia-related EEG alteration during VF episodes depends on the duration of cardiac arrest. In females EEG changes tended to last longer than in males, however, this finding has to be confirmed. An association with other clinical parameters has not been observed. Limitation of VF duration appears to be the most important factor to avoid prolonged cerebral ischemia.

[Immunologic tolerance after experimental liver transplantation]

Allografts in the rat liver are rejected less vigorously than other primarily vascularized allografts; they show a better survival rate and induce donor-specific unresponsiveness or tolerance in some donor-recipient combinations. This overview focuses on the immunologic mechanisms of this privileged status of liver allografts. A variety of possible mechanisms, such as generation of suppressor T-cells, humoral factors and microchimerism, has been related to the observed hyporeactivity. A further analysis of these phenomena may enhance the development of clinical organ transplantation protocols that allow for establishment of donor-specific unresponsiveness without the need for life-long immunosuppression.

Glutamate-induced calcium responses in rat primary cortical cultures are potentiated by co-administration of glutamate transport inhibitors

The effects of glutamate uptake inhibitors on the L-glutamate-induced increase in intracellular calcium concentrations were assessed in rat primary cortical cultures. The glutamate (10 microM)-induced rise in intracellular calcium concentrations was strongly and dose dependently increased and prolonged by simultaneous administration of micromolar concentrations of the reference glutamate transport inhibitors, L-trans-pyrrolidine-2,4-dicarboxylate (PDC) and D- or L-threo-beta-hydroxyaspartate. PDC in concentrations up to 10 microM showed no effect on intracellular calcium when administered alone. The anticancer drug tamoxifen, which was found to be effective as a glutamate transport inhibitor, did not increase but prolonged the cellular calcium response to glutamate, indicating that it had a different mechanism of action compared to that of standard glutamate transport inhibitors. The findings suggest that compounds which inhibit the glutamate transporter may potentiate the excitatory glutamatergic signal of cultured neurons when administered together with glutamate.

Localization of alpha-fetoprotein in developing chick amniotic membrane

The aim of this work was to investigate the localization of alpha-fetoprotein (AFP) in amniotic membrane (AM). By using the immunoperoxidase technique in several developmental stages, which reflected the changes of structure of the AM germinal layers, AFP was detected earliest in 7-day AM and localized selectively in the ectodermal cell layer. This was the only developmental stage at which AM occurred as a two-layer structure, ectoderm and somatic mesoderm, and was AFP-positive. In the zone of fusion of the AM with the inner wall of the allantoic sac, cystlike cavities were observed which were markedly immunoreactive to AFP. In those membranes where fusion had consolidated and a four-layer structure could be distinguished: ectoderm, somatic mesoderm, splanchnic mesoderm and endoderm, AFP was localized in the ectodermal cells and in the splanchnic mesoderm resulting from the inner wall of the allantoic sac. Both mesodermal layers could be distinguished by means of the AFP immunoreaction since AFP labelled the splanchnic, but not the somatic mesoderm. At later developmental stages, e.g. 18-day, the AM had a three-layer structure and AFP was localized selectively throughout the splanchnic mesoderm. The disappearance of the somatic mesoderm coinciding temporarily with the disappearance of AFP from the ectodermal cells, suggests that the presence of AFP in such cells could depend on some factors related to the somatic mesoderm.

Internally quenched fluorogenic substrate for furin

A new substrate for furin, Abz-Arg-Val-Lys-Arg-Gly-Leu-Ala-Tyr(NO2)-Asp-OH, has been synthesized and characterized. The peptide is an internally quenched fluorogenic substrate. The kinetic parameters are Km = 3.8 microM, kcat = 29.3 s-1, and kcat/KM = 7,710,000 M-1 s-1. The substrate is efficiently cleaved by furin; its kcat/KM value is over 2000-fold higher than that of the commonly used substrate Boc-Arg-Val-Arg-Arg-AMC.

Expression of neutral glycosphingolipids and gangliosides in human skeletal and heart muscle determined by indirect immunofluorescence staining

The expression of neutral glycosphingolipids and gangliosides has been studied in human skeletal and heart muscle using indirect immunofluorescence microscopy. Transversal and longitudinal cryosections were immunostained with specific monoclonal and polyclonal antibodies against the neural glycosphingolipids lactosylceramide, globoside, Forssman glycosphingolipid, gangliotetraosylceramide, lacto-N-neotetraosylceramide and against the gangliosides GM3(Neu5Ac) and GM1(Neu5Ac). To confirm the lipid nature of positive staining, control sections were treated with methanol and chloroform:methanol (1:1) before immunostaining. These controls were found to be either negative or strongly reduced in fluorescence intensity, suggesting that lipid bound oligosaccharides were detected. In human skeletal muscle, lactosylceramide was found to be the main neutral glycosphingolipid. Globoside was moderately expressed, lacto-N-neotetraosylceramide and gangliotetraosylceramide were minimally expressed and Forssman glycosphingolipid was not detected in human skeletal muscle. The intensities of the immunohistological stains of GM3 and GM1 correlated to the fact that GM3 is the major ganglioside in skeletal muscle whereas GM1 is expressed only weakly. In human heart muscle globoside was the major neutral glycosphingolipid. Lactosylceramide and lacto-N-neotetraosylceramide were moderately expressed, gangliotetraosylceramide was weakly expressed and the Forssman glycosphingolipid was not expressed at all in cardiac muscle. GM3 and GM1 were detected with almost identical intensity. All glycosphingolipids were present in plasma membranes as well as at the intracellular level.

N-(sulfonyloxy)phthalimides and analogues are potent inactivators of serine proteases

A series of 2-(sulfonyloxy) and 2-(acyloxy)-1H-isoindole-1,3(2H)-diones and analogous 1H-benz[de]isoquinoline-1,3(2H)-diones was prepared, and their potential to inactivate chymotrypsin was investigated. The N-(sulfonyloxy) and N-(acyloxy)phthalimides were found to be potent inactivators of chymotrypsin and related serine proteinases. For the most active compounds, N-(dansyloxy)phthalimide and N-(tosyloxy)phthalimide, the second-order rate constant of chymotrypsin inactivation was in the range of 250,000 m-1 s-1. N-(Mesyloxy)-phthalimide was the most active compound for inactivation of leukocyte elastase. It was shown that these compounds act as true suicide substrates. Enzyme-catalyzed opening of the heterocyclic ring results in the formation of an acyl-enzyme with attached O-acyl or O-sulfonylhydroxamic acid moiety. Subsequent Lossen rearrangement leads to the formation of a highly reactive isocyanate, which irreversibly modifies the target protease.

A novel fluorogenic substrate for ribonucleases. Synthesis and enzymatic characterization

The synthesis and enzymatic characterization of DUPAAA, a novel fluorogenic substrate for RNases of the pancreatic type is described. It consists of the dinucleotide uridylyl-3',5'-deoxyadenosine to which a fluorophore, o-aminobenzoic acid, and a quencher, 2,4-dinitroaniline, have been attached by means of phosphodiester linkages. Due to intramolecular quenching the intact substrate displayed very little fluorescence. Cleavage of the phosphodiester bond at the 3'-side of the uridylyl residue by RNase caused a 60-fold increase in fluorescence. This allowed the continuous and highly sensitive monitoring of enzyme activity. The substrate was turned over efficiently by RNases of the pancreatic type, but no cleavage was observed with the microbial RNase T1. Compared to the dinucleotide substrate UpA, the specificity constant with RNase A, RNase PL3 and RNase U(s) increased 6-, 18-, and 29-fold, respectively. These differences in increased catalytic efficiency most likely reflect differences in the importance of subsites on the enzyme in the binding of elongated substrates. Studies on the interactions of RNase inhibitor with RNase A using DUPAAA as a reporter substrate showed that it was well suited for monitoring this very tight protein-protein interaction using pre-steady-state kinetic methods.

Expression of gangliosides GM3 (NeuAc) and GM3 (NeuGc) in myelomas and hybridomas of mouse, rat, and human origin

In this study gangliosides from various myelomas and hybridomas of mouse, rat, and human origin were characterized by thin-layer and high-performance liquid chromatography, immunological methods (overlay technique) and fast atom bombardment mass spectrometry. Exclusively GM3 substituted with C24:1- and C16:0-fatty acid, was found in all B cell-derived cell lines. C18 sphingosine was the single long chain base in each GM3 ceramide portion. The mouse myeloma (NS-1) and all hybridomas, obtained by fusion of mouse, rat, or human B lymphocytes with murine myelomas, showed high GM3 (NeuGc) content (> 75%) and low GM3 (NeuAc) expression. Absolute amounts of GM3 ranged from 0.2 up to 0.8 mg x 10(-9) cells. Normally, human cells do not express NeuGc, and an Epstein-Barr virus-transformed human B lymphocyte line analyzed in this study retained this sialylation status, expressing exclusively GM3 (NeuAc) (100%). The fusion of human B lymphocytes with mouse myelomas led to high GM3 (NeuGc) expression (average about 85%) in all mouse/human heterohybridomas examined. Our results indicate the chromosomal gene "transfer" and/or the activation of enzymes involved in NeuGc-biosynthesis due to the somatic cell fusion process, which might explain the mouse dominance in the manifestation of the NeuGc-phenotype in hybridomas of human origin.

Quantitation of electrophoretically separated proteins in the submicrogram range by dye elution

A new method for the fast, reliable and reproducible submicrogram quantitation of proteins separated by different electrophoretic techniques is presented. The method is based on a modified sensitive staining technique using Coomassie Brilliant Blue G-250 in colloidal solution combined with an optimized elution procedure of the bound dye in a 3% w/v solution of sodium dodecyl sulfate followed by photometric determination of dye concentration in the eluate. In addition a new method is provided for background correction, even suitable for gels showing strong background staining. The staining procedure allows the detection of 20 ng depending on the nature of the protein and the separation technique used. Quantitation is linear at least in the range from 50 ng to 10 micrograms and highly reproducible even under non-optimized conditions. The presented method can be applied to sodium dodecyl sulfate-electrophoresis, isoelectric focusing and two-dimensional electrophoresis.

[Pilot study of the occurrence of Chlamydia psittaci infections in commercial turkey flocks in Niedersachsen]

Turkeys from 8 commercial flocks, of which were 6 clinically healthy, were examined by use of enzyme-linked immunosorbent assay systems for genus-specific Chlamydia antigens and also for antibodies against Chlamydia psittaci in 4 flocks. Results of the tests indicate the presence of Chlamydia psittaci infections in all 8 flocks. The percentage of combined cloacal and conjunctival swabs positive for Chlamydia antigen ranged from 20-91% [20-70%] whereas the percentage of antibody-positive serum samples ranged from 81-100%. Our findings suggest, that the prevalence of Chlamydia psittaci infections in clinically healthy turkey flocks is higher than hitherto suspected.

Interaction of semisynthetic variants of RNase A with ribonuclease inhibitor

Derivatives of ribonuclease A (RNase A) with modifications in positions 1 and/or 7 were prepared by subtilisin-catalyzed semisynthesis starting from synthetic RNase 1-20 peptides and S-protein (RNase 21-124). The lysyl residue at position 1 was replaced by alanine, whereas Lys-7 was replaced by cysteine that was specifically modified prior to semisynthesis. The enzymes obtained were characterized by protein chemical methods and were active toward uridylyl-3',5'-adenosine and yeast RNA. When Lys-7 was replaced by S-methyl-cysteine or S-carboxamido-contrast, the catalytic properties were only slightly altered. The dissociation constant for the RNase A-RI complex increased from 74 fM (RNase A) to 4.5 pM (Lys-1, Cys-7-methyl RNase), corresponding to a decrease in binding energy of 10 kJ mol-1. Modifications that introduced a positive charge in position 7 (S-aminoethyl- or S-ethylpyridyl-cysteine) led to much smaller losses. The replacement of Lys-1 resulted in a 4-kJ mol-1 loss in binding energy. S-protein bound to RI with Ki = 63.4 pM, 800-fold weaker than RNase A. This corresponded to a 16-kJ mol-1 difference in binding energy. The results show that the N-terminal portion of RNase A contributes significantly to binding of ribonuclease inhibitor and that ionic interactions of Lys-7 and to a smaller extent of Lys-1 provide most of the binding energy.

Different distributions of glycosphingolipids in mouse and rabbit skeletal muscle demonstrated by biochemical and immunohistological analyses

The expression of neutral glycosphingolipids and gangliosides was investigated in mouse and rabbit skeletal muscle by means of biochemical and immunochemical techniques. Neutral glycosphingolipids from muscle of the inbred rabbit strain used in this study showed a simple TLC pattern, comprising mainly monohexosylceramide. In addition to this compound, lactosylceramide, lacto-N-neotetraosylceramide, globoside and Forssman GSL were detected in mouse muscle. The major ganglioside in both species was GM3; GM3 (Neu5Ac) and GM3(Neu5Gc) were found in a 3:1 ratio in mouse muscle, whereas the absence of GM3(Neu5Gc) is characteristic of rabbit muscle. As a general structural feature of all muscle GM3 gangliosides investigated, a C18 fatty acid and C18 sphingosine were the major components besides minor C22 and C24:1 fatty acids of the respective ceramide portions, as revealed by positive and negative ion FAB-MS. alpha 2-3 sialylated lacto-N-neotetraosyl-ceramide (sialylparagloboside) was expressed in both species, whereas the alpha 2-6 sialylated isomeric compound was found only in mouse muscle. Minute quantities of ganglio-series GM1, GD1a, GD1b, and GT1b were detected in muscles from both species. Glycosphingolipid expression could be confirmed immunohistochemically by examining transverse and longitudinal cryosections of skeletal muscle samples. The results provide the basis for the investigation of muscle specific glycosphingolipids that might modulate membrane protein functions in muscle.

Residues 287-301 of human ribonuclease inhibitor do not affect ribonuclease activity and inhibitor binding; a reply

Residues 287-301 of human placental ribonuclease inhibitor have been reported to inhibit pancreatic ribonuclease A in a similar way as the entire inhibitor (Crevel-Thieffry, I., Cotterill, S. and Schuller, E. (1992) Biochim. Biophys. Acta 1122, 107-112). Using three different assays, we were unable to observe inhibition by the synthetic peptide. Moreover, the peptide did not compete with the entire inhibitor for binding to RNAase A.

Novel N-peptidyl-O-acyl hydroxamates: selective inhibitors of cysteine proteinases

A series of N-peptidyl-O-acyl hydroxamates with a lysine in P1 was synthesized and tested as inactivators of lysosomal cysteine proteinases (cathepsins S, L, B and H) and trypsin-like serine proteinases (trypsin, thrombin, plasmin, t-PA). N-peptidyl-O-acyl hydroxamates were shown to be selective inhibitors of cysteine proteinases. With the exception of cathepsin H, the lysosomal cysteine proteinases were inactivated 2-5 orders of magnitude more rapidly than serine proteinases with a comparable primary substrate specificity. The highest second-order rate constants of inactivation for the cysteine proteinases are in the range of 10(5)-10(6) M-1 s-1. The order of inhibitor specificity for the cysteine proteinases is comparable to the enzyme's substrate specificity.

Crystallization of porcine liver ribonuclease inhibitor a member of the family of proteins containing leucine-rich repeats

Single crystals of the RNase inhibitor from porcine liver have been obtained from 30 to 34% saturated ammonium sulphate solutions at pH 6.0 to 7.2, containing 20 mM dithiothreitol, at room temperature over a period of two to three weeks. Because the inhibitor contains 30 1/2-cystinyl residues, all of which occur in the free thiol form, crystallization experiments were carried out in a desiccator under a nitrogen atmosphere. The crystals belong to the tetragonal space group I4, with cell dimensions a = b = 134.76 A and c = 83.65 A. The asymmetric part of the unit cell contains two molecules with a molecular mass of 49,093 Da, as could be shown with a self-rotation function calculated in the resolution range 10.0 to 3.2 A. The crystals diffract to at least 3.2 A resolution and are suitable for an X-ray structure determination.

Selective detection of terminally alpha 2-3 and alpha 2-6 sialylated neolacto-series gangliosides by immunostaining on thin layer chromatograms

A method for selective detection of terminally alpha 2-3 and alpha 2-6 sialylated neolacto-series gangliosides has been developed. The procedure involves separation of gangliosides on high performance thin layer chromatography plates, fixation of the silica gel, treatment with Vibrio cholerae neuraminidase and incubation of the plates with nLcOse4Cer-specific antibodies. Alkaline phosphatase-conjugated second antibodies were used to visualize bound first antibodies by generating a blue dye from 5-bromo-4-chloro-3-indolyl phosphate. Neolacto-series gangliosides from human granulocytes with terminally alpha 2-3 and alpha 2-6 linked N-acetylneuraminic acid served as examples. Neuraminidase treatment of gangliosides with alpha 2-3 substituted sialic acid is necessary prior to immunostaining whereas alpha 2-6 sialylated gangliosides can be detected without enzyme treatment. Steric hindrance of sialic acid bound in position 3 to terminal galactose prevented binding of the antibody to the Gal beta 1-4GlcNAc sequence whereas sialylation in position 6 to terminal galactose does not hinder recognition. The procedure is viable for the detection of amounts down to 10 ng of gangliosides. This method should be useful to screen gangliosides from different tissues or cell lines for the presence of such components, especially if only small quantities of material are available.

Quantitation of proteins separated in N, N'-1,2-dihydroxyethylenebisacrylamide-crosslinked polyacrylamide gels

A simple and rapid method for the quantitation of proteins separated either by sodium dodecyl sulfate-electrophoresis or by isoelectric focusing in slab gels is presented. The method is based on the solubility of polyacrylamide gels crosslinked with N, N'-1, 2-dihydroxyethylenebisacrylamide (DHEBA) in periodic acid. After electrophoretic separation proteins are stained with Coomassie brilliant blue G-250. DHEBA gels show considerable swelling during the staining and destaining process but can be shrunk to their normal size in a 10% (w/v) solution of ammonium sulfate. Stained bands are cut from the gel and solubilized in periodic acid. During dissolution the dye decolorizes. Protein concentration in the solution is determined by a modified Coomassie dye-binding assay. Quantitation is linear in the range of 100 ng to 5 micrograms and not disturbed by dissolved gel. Separations in N, N'-1, 2-dihydroxyethylenebisacrylamide-crosslinked gels show qualities similar to those in normal crosslinked gels.

Mapping of the catalytic site of CHO-t-PA and the t-PA variant BM 06.022 by synthetic inhibitors and substrates

BM 06.022 is a t-PA deletion variant that is produced as inactive inclusion bodies in Escherichia coli and transformed into the native form by an in vitro refolding process. Until now, no X-ray and NMR structures of BM 06.022 were available. Therefore a detailed kinetic analysis of the hydrolysis of peptide substrates and of the inhibition by several benzamidine-derived inhibitors was carried out in order to assess that the active site region of the protease domain of BM 06.022 is correctly structured in comparison with t-PA. Our data reveal that the single-chain as well as the two-chain form of BM 06.022 and native t-PA are similar in catalytic and in inhibitor binding properties. This indicates that the active site and the highly complex rearrangement of t-PA upon cleavage of the Arg275-Ile276 bond are maintained in BM 06.022.

Avian paramyxovirus serotype 1 (Newcastle disease virus)--infections in falcons

From eight falcons and one pigeon which died from NDV over a period of 15 months in Dubai, United Arab Emirates, PMV-1 viruses were isolated on quail embryo cell cultures. The identification of all 9 strains were achieved with the haemagglutination inhibition test against polyclonal chicken PMV-1 antiserum, against mouse monoclonal antibodies as well as with the immunoperoxidase test. Intracerebral pathogenicity index and intravenous pathogenicity index tests were also carried out. Although the virus isolates in this study fell into two distinct groups, the overall clinical symptoms displayed by the falcons tailed to demonstrate any trends or specificity unique to a group. The isolate obtained from a pigeon was similar to the isolates from one group of the falcons and showed no identity with the pigeon variant virus.

Occurrence of Campylobacter spp. in young gulls, duration of Campylobacter infection and reinfection by contact

Two groups of three week old Herring Gulls (Larus argentatus) were held to observe the carrier state with Campylobacter. All 27 birds of group I excreted Campylobacter jejuni biotype III when they were caught from their colony. Four weeks later all but one were negative, indicating that the carrier state lasts until about the seventh week of life, with self-elimination if infection with another Campylobacter species is prevented by housing in a closed environment as in this study. Only one bird became reinfected one year later when gulls from group I were brought into contact with gulls from group II, consisting of ten freshly caught gulls, four of which were infected with the same biotype of Campylobacter, indicating that there might be some kind of immunity protection against infection with the same biotype of Campylobacter spp.

Functional characterization of skin-infiltrating lymphocytes in atopic dermatitis

Skin-infiltrating lymphocytes (SIL) were isolated from skin biopsies of patients with hyperimmunoglobulin E (IgE) atopic dermatitis (AD) and expanded in vitro in the presence of IL-2 in combination with IL-4. Phenotypic analysis of skin-derived cells revealed the predominance of CD4+ T helper/inducer phenotype in SIL populations. In 3H-thymidine incorporation assays, SIL showed proliferation in response to IL-2, IL-3, IL-4, ionomycin (Io) + 12-o-tetradecanoyl-phorbol-13-acetate (TPA) and OKT3 + TPA. OKT4 with and without TPA did not induce proliferation. Tumour necrosis factor alpha (TNF-alpha) did not block proliferative responses of SIL to IL-2 and IL-4. Cultured SIL showed no cytotoxic activity against K562 and Jurkat target cells. Expanded skin-derived T cells were tested for their capacity to secrete several cytokines in vitro. SIL secreted significant amounts of IL-4, GM-CSF and TNF-alpha upon stimulation with mitogens but failed to secrete IFN-gamma. Io in combination with phorbol-ester induced the secretion of larger amounts of IL-4, GM-CSF, TNF-alpha and low amounts of IFN-gamma. The data indicate that SIL derived from AD lesions were defective in their capacity to secrete IFN-gamma but were enriched in T cells capable of producing IL-4 upon stimulation. The results support the possibility of a predominant 'TH2-like' cell-mediated immune response in lesional skin of AD patients.

Tumor-infiltrating lymphocytes isolated from a Ki-1-positive large cell lymphoma of the skin. Phenotypic characterization and analysis of cytokine secretion

Tumor-infiltrating lymphocytes (TIL) were obtained from a biopsy of a patient with a Ki-1-positive large cell lymphoma of the skin. Immunohistologic studies of the large anaplastic tumor cells showed an "aberrant" T "helper/inducer" phenotype (CD30 + CD3-CD4+ CD8-IL-2R + HLA-DR+). Using cDNA probe for the constant region of the T-cell receptor (TCR) beta gene, the cells were identified by their distinct monoclonal rearrangement of T-cell receptor (TCR)-beta DNA. Tumor cells isolated from biopsies were cultured in the presence of interleukin-2 (IL-2). Outgrowing lymphocytes were cloned, expanded in vitro, and 11 clones were subjected to phenotypic analysis: ten clones showed a predominantly CD4-positive T "helper/inducer" phenotype whereas one clone expressed CD8 T "cytotoxic/suppressor" antigens. In contrast to the tumor cells, cells of all clones grown in vitro expressed the TCR-associated CD3 complex. Furthermore, cells from all clones analyzed expressed CD5, CD7, CD45RO (UCHL1), CD11a (LFA-1), CD25, and HLA-DR antigens. Cells of two of ten CD4-positive clones expressed CD45RA (2H4) in addition to UCHL1. T-cell clones isolated from the tumor and grown in vitro exhibited individual DNA restriction band patterns different from that of a DNA tumor biopsy specimen. Therefore, the authors conclude that these T-cell clones represent presumably nonmalignant TIL. All clones tested secreted interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha in vitro. Nine of 11 clones were found to secrete additionally IL-2 and IL-4 upon stimulation with phytohemagglutinin (PHA) whereas two clones did not secrete detectable amounts of IL-4. Selective growth of TIL in the presence of IL-2 opens the possibility to use these cells in adoptive immunotherapy of cutaneous T-cell lymphoma (CTCL). Cytokines secreted by TIL cells in vitro (IL-2, IL-4, IFN-gamma, TNF-alpha) may be involved in their antitumorigenic activity. Moreover, these data implicate that CD4-positive TIL derived from CTCL cannot be grouped into different subsets based on the production of IL-2, IL-4, IFN-gamma, and TNF-alpha.

Structural studies of gangliosides from the YAC-1 mouse lymphoma cell line by immunological detection and fast atom bombardment mass spectrometry

YAC-1 cells were propagated in bioreactors in 1 l and 7.5 l volumes. The cells were metabolically labelled with D-[1-14C]galactose and D-[1-14C]glucosamine. The ganglioside fraction, purified by DEAE-Sepharose and silica gel column chromatography, showed on thin layer chromatography four major bands with mobilities between GM1 and GD1a. Gangliosides, obtained by further purification steps including high performance liquid chromatography on silica gel 60 columns with a gradient system of isopropanol:hexane:water, and preparative high performance TLC were characterized by (1) immunostaining of corresponding asialogangliosides obtained by mild acid hydrolysis and neuraminidase treatment and (2) fast atom bombardment mass spectrometry of native and permethylated samples and methylation analysis of GM1b ganglioside. As well as small amounts of GM2 and GM1, the major gangliosides found in the complex mixture were GM1b and GalNAc-GM1b. The structural heterogeneity of these gangliosides was caused by (a) substitution of the ceramide moiety by fatty acids of different chain length and degree of unsaturation (C16:0, C24:0, C24:1) and (b) N-substitution of the sialic acid moieties with either acetyl or glycolyl groups. Disialogangliosides were detected only in low amounts and will be the subject of further investigation. A polyclonal chicken antiserum was raised against IVNeuAc-GgOse5Cer. The antiserum was highly specific for gangliosides (IVNeuAc and IVNeuGc) and asialogangliosides with a GgOse5Cer backbone. No cross-reaction with GM1b or GgOse4Cer was observed.

[The occurrence of Campylobacter spp. and Salmonella spp. in gulls in northern Germany]

Out of a total of 207 gulls--20 Black headed gulls, 185 Herring gulls and 2 Common gulls--128 (62%) and 23 (11%) birds, respectively, were infected with Campylobacter spp. (C.) and Salmonella spp. C. jejuni was predominant in gulls less than two years old (89%) and C. coli in older birds (75%). Furthermore, the infection rate with Campylobacters was depending on the habitats of the birds. The rate for C. jejuni and C. coli, respectively, was in gulls from regional garbage dumps 78% and 4%, from the coast 58% and 21%, and from islands 47% and 47% of the isolations in the corresponding area. Salmonellae were mainly isolated in the period from September to February from gulls less than one year old and from birds from the coast.

Interleukin-4 promotes the expansion of skin-infiltrating lymphocytes from atopic dermatitis in vitro

Functional studies of lymphocytes in atopic dermatitis (AD) have so far focused on peripheral blood mononuclear cells (PBMC), whereas cells at the involved site, the skin, have not been examined. Accordingly, we have developed methods to generate lymphocyte cultures from biopsies of inflammatory skin areas. Skin-infiltrating lymphocytes (SIL) were isolated from skin biopsies of 6 patients with severe AD and expanded in vitro in the presence of interleukin-2 (IL-2) without additional antigens. After 6-10 d in culture, outgrowth of mononuclear cells from biopsy tissue was observed in all cases. Phenotypic analysis of skin-derived cells revealed the predominance of CD4+ T-helper/inducer phenotype in SIL populations. Parallel cultures of SIL and PBMC showed an increase and expansion of CD8+ T cells in cultured PBMC, whereas the CD4+ phenotype was predominant in SIL cultures. As indicated by their expression of HLA-DR and CD25 antigens, most of the SIL were activated and the cells mainly expressed T-cell receptors (TCR) composed of alpha and beta chains. Different strategies for expansion of SIL in vitro were examined. High levels of IL-4 (1,000 U/ml) in combination with IL-2 (50 U/ml or 1,000 U/ml) preferentially promoted growth of SIL derived from AD and were much more effective than IL-2 alone. No cells expanded in cultures with IL-4 alone. SIL grown with high concentrations of IL-4 contained a significant proportion of double-positive CD4+8+ cells. No other marked differences were observed in the distribution of T cell subsets in cultures propagated under different conditions for 21 d. Our results demonstrate the feasibility of growing infiltrating T lymphocytes from inflammatory skin of AD patients. The use of high concentrations of IL-2 in combination with high levels of IL-4 allows a large expansion of these cells and thus represents a useful strategy to expand cells for further functional and molecular biologic studies.

Inhibition of the protein C activator Protac, a serine proteinase from the venom of the southern copperhead snake Agkistrodon contortrix contortrix

ProtacR, the single chain glycoprotein in the venom of Agkistrodon contortrix snake subspecies and related pit vipers has found broad application as a protein C activator in blood coagulation research and diagnosis. Inhibition studies were performed to further elucidate the nature of this serine proteinase. Benzamidine derivatives are poor inhibitors of ProtacR. Only a few 4-amidinoanilides of N alpha-substituted omega-phenyl-alpha-aminoalkylcarboxylic acids exert potent inhibitory activities. The active site of ProtacR appears to be accessible only for inhibitors with well-fitting structural features.

Inhibition of chymotrypsin and pancreatic elastase by 4H-3,1-benzoxazin-4-ones

Eight 3,1-Benzoxazin-4-ones have been used to inactivate chymotrypsin and pancreatic elastase. Whereas 6,7-dimethoxy substitution only slightly decreased the acylation rate constant, the deacylation reaction was nearly unaffected. Bulky alkoxy groups in position 2 of the heterocyclic moiety were shown to increase enormously the acylation rate of chymotrypsin, but not that of elastase.