Case report: fatal seronegative rickettsial infection diagnosed by the polymerase chain reaction

A previously healthy man presented with a five day history of high fever and headache, later followed by rash and the appearance of jaundice. On the second hospital day, he suddenly developed seizures, lapsed into a coma, and died. Polymerase chain reaction (PCR) amplification revealed a 434 base pairs DNA fragment common to the genome of typhus and spotted fever group rickettsiae in the patient's blood (estimated at about 1 x 10(2) organisms/ml), and to a lesser degree in the cerebrospinal fluid. However, serological tests for rickettsiae remained negative. PCR techniques may confirm the diagnosis at an early stage, even though the rickettsemia may be minimal and the patient seronegative.

Divergent envelope E2 alphavirus sequences spanning amino acids 297 to 352 induce in mice virus-specific protective immunity and antibodies with complement-mediated cytolytic activity

We have proposed a general algorithm for identification of potential immunoprotective domains (cassettes) on the envelope E2 polypeptide of alphaviruses (H. Grosfeld, B. Velan, M. Leitner, S. Cohen, S. Lustig, B.E. Lachmi, and A. Shafferman, J. Virol. 63:3416-3422, 1989). To assess the generality of our approach, we compared analogous E2 cassettes from Sindbis virus (SIN) and Semliki Forest virus (SFV), two alphaviruses which are philogenetically very remote. The antigenically distinct SFV E2 and SIN E2 cassettes exhibit comparable immunological characteristics. Most significantly, the SIN E2 LMN cassette cluster (E2 amino acids 297 to 352 fused to beta-galactosidase), like the analogous SFV E2 LMN cassettes, elicited high titers of antivirus antibodies in mice and proved to be highly effective in protection against lethal challenge. Mice immunized with SIN E2 LMN were completely protected against intracerebral challenge of 10 to 100 50% lethal doses of different neurovirulent SIN strains. Anti-SIN LMN antibodies, like anti-SFV LMN antibodies, lacked in vitro neutralizing activity, yet both exerted protection against homologous challenge upon transfer to mice. The two antibody preparations exhibited virus-specific complement-mediated cytolysis of cells infected with the homologous but not heterologous virus. These results suggest a possible mechanism for virus-specific E2 LMN-induced protection and demonstrate the generality of our methodology for deciphering immunogenic and protective domains in alphavirus systems. Results suggest also that the E2 LMN sequence of any given alphavirus should be considered as a component of a synthetic vaccine against that specific virus.

Glutamate uptake disguises neurotoxic potency of glutamate agonists in cerebral cortex in dissociated cell culture

The pharmacological properties of glutamate agonists were compared in astrocyte-rich and astrocyte-poor cultures derived from embryonic rat cerebral cortex. The object of this investigation was to determine the extent to which glutamate uptake might influence the receptor-mediated neurotoxic actions of these compounds. In astrocyte-rich cultures, using 30 min exposures, we observed that the potencies of the poorly transported agonists NMDA (35 microM) and D-glutamate (89 microM) were higher than that of L-glutamate (205 microM). In astrocyte-poor cultures, L-glutamate was much more potent, with an EC50 of 5 +/- 4 microM (3-12 microM), for a 30 min exposure, whereas the potencies of NMDA and D-glutamate were essentially unchanged. L- and D-aspartate were also more effective in astrocyte-poor cultures, again with EC50 values of approximately 6-10 microM, as compared with 130 and 108 microM, respectively, in astrocyte-rich cultures. In other experiments, blocking sodium-dependent glutamate uptake in astrocyte-rich cultures, by using a sodium-free medium, made glutamate as potent an agonist as in astrocyte-poor cultures. Finally, we directly assessed the glutamate uptake system in astrocyte-rich and astrocyte-poor cultures and found that uptake was reduced approximately 25-fold in the astrocyte-poor cultures. These results show that in the presence of abundant astrocytes the neurotoxic potencies of L-glutamate, L-aspartate, and D-aspartate are substantially under-estimated.

The effect of elimination of intersubunit disulfide bonds on the activity, assembly, and secretion of recombinant human acetylcholinesterase. Expression of acetylcholinesterase Cys-580----Ala mutant

Site-directed mutagenesis was used to study the cysteine residue involved in the assembly of human acetylcholinesterase (HuAChE) catalytic subunits. Substitution of the cysteine at position 580 by alanine resulted in impairment of interchain disulfide bridge formation; the mutagenized enzyme (C580A) was secreted from recombinant cells in the monomeric form and failed to assemble into dimers. The mutant monomeric HuAChE did not differ from the native oligomeric enzyme neither in rate of catalysis nor in affinity to acetylthiocholine. Mutant monomers were also shown to retain the acetylcholinesterase characteristic sensitivity to high substrate concentrations. The mutation did not seem to affect the efficiencies of either synthesis or secretion of recombinant HuAChE polypeptides, as was demonstrated in cell lines derived from human embryonic kidney (293 cells) as well as from a human neuroblastoma (SK-N-SH). Furthermore, the mutation did not lead to an increase in accumulation of intracellular HuAChE polypeptides, suggesting that export of acetylcholinesterase from cells may not be coupled to subunit assembly.

Delineation of protective epitopes on the E2-envelope glycoprotein of Semliki Forest virus

Two short linear peptides, 17 and 14 amino acids long, on the Semliki Forest virus (SFV) E2-envelope polypeptide are shown to be involved in the protection of mice against lethal challenge with SFV. Peptides corresponding to these two regions, designated H and L, were selected for study on the basis of our model for prediction of protective epitopes on E2 polypeptide of alphaviruses. These peptides were produced in Escherichia coli as recombinant proteins fused to the amino terminus of beta-galactosidase. Both the H epitope (amino acid positions 227-243 on E2) and L epitope (amino acid positions 297-310) are recognized by antibodies raised against SFV, and both trigger antibodies that interact with native SFV-E2. Vaccination of mice with the H-beta-galactosidase polypeptide confers 64-87% protection against a lethal viral challenge (250 LD50), and immunization with L-beta-galactosidase leads to 23-66% protection of challenged mice. The efficacy of the L-based synthetic vaccine could be improved further (up to 100% protection) by presentation of this epitope as a dimer fused to beta-galactosidase. These results provide evidence that the algorithm and the methodology proposed by us previously are effective tools for identification of linear protective epitopes on E2-envelope of SFV.

Recombinant human acetylcholinesterase is secreted from transiently transfected 293 cells as a soluble globular enzyme

1. Coding sequences for the human acetylcholinesterase (HuAChE; EC 3.1.1.7) hydrophilic subunit were subcloned in an expression plasmid vector under the control of cytomegalovirus IE gene enhancer-promoter. The human embryonic kidney cell line 293, transiently transfected with this vector, expressed catalytically active acetylcholinesterase. 2. The recombinant gene product exhibits biochemical traits similar to native "true" acetylcholinesterase as manifested by characteristic substrate inhibition, a Km of 117 microM toward acetylthiocholine, and a high sensitivity to the specific acetylcholinesterase inhibitor BW284C51. 3. The transiently transfected 293 cells (100 mm dish) produce in 24 hr active enzyme capable of hydrolyzing 1500 nmol acetylthiocholine per min. Eighty percent of the enzymatic activity appears in the cell growth medium as soluble acetylcholinesterase; most of the cell associated activity is confined to the cytosolic fraction requiring neither detergent nor high salt for its solubilization. 4. The active secreted recombinant enzyme appears in the monomeric, dimeric, and tetrameric globular hydrophilic molecular forms. 5. In conclusion, the catalytic subunit expressed from the hydrophilic AChE cDNA species has the inherent potential to be secreted in the soluble globular form and to generate polymorphism through self-association.

Semliki Forest virus E2 envelope epitopes induce a nonneutralizing humoral response which protects mice against lethal challenge

Along the 422 amino acids of the Semliki Forest virus (SFV) E2 envelope glycoprotein, we identified 13 peptide cassettes (ranging in size from 15 to 25 amino acids and designated A through N) that contain hydrophilic sequences flanked by amino acid sequences conserved in the E2 envelopes of the alphavirus family. Six peptide blocks containing either a single cassette or two to three contiguous cassettes (A, BC, DE, FG, HIK, and LMN) were produced in Escherichia coli as recombinant proteins fused to the N terminus of beta-galactosidase. All of the SFV E2 recombinant polypeptides except A-beta-galactosidase were recognized on Western blots (immunoblots) by anti-SFV polyclonal antisera. In addition, these five recombinant proteins induced in mice antibodies that interacted specifically with SFV E2 protein on Western blots as well as with the intact virions in an enzyme-linked immunosorbent assay. The six hybrid proteins were used to vaccinate mice and were tested for the ability to confer resistance against lethal doses of SFV. Peptides BC and HIK, located at amino acid positions 114 to 149 and 216 to 288, respectively, of E2, protected partially (40 to 60%) against SFV challenge. A third peptide, LMN, located between amino acid positions 289 and 352, rendered mice totally resistant to an SFV challenge of 250 50% lethal doses. The partially protective effects of the BC and HIK cassettes and the high efficacy of the LMN cassette were consistently demonstrated, independent of the adjuvant (complete Freund or alum), immunization protocol, and strain of mice used. None of the antisera raised against any given cassette could neutralize the virus in an in vitro tissue culture assay or in a plaque reduction neutralization test. Nevertheless, passive transfer experiments demonstrated that in the case of LMN, the protective effect was mainly of a humoral nature.

Expression of Shiga toxin epitopes in E. coli immunological characterization

Synthetic oligodeoxynucleotides encoding for two peptides corresponding to residues 9-21 and 19-31 in the amino acid sequence of the B subunit of Shiga toxin were prepared and inserted into pTOZ plasmid, in phase with the lacZ gene. The resultant vectors were used for transfection of E. coli. The bacteria containing the recombinant DNA expressed the respective peptides in the form of fusion proteins with beta-galactosidase. The N-terminal region of the Shiga toxin B subunit, containing the two peptides, was previously identified as a relevant epitope of the toxin, leading to the induction of neutralizing antibodies. The present study demonstrates that the bacterial extracts containing the fusion proteins as the products of the recombinant vectors, when used for immunization of rabbits, elicited a humoral immune response which was specific toward the respective peptides. Furthermore, the antibodies cross-reacted with the intact Shiga toxin.

Production of monoclonal antibodies toward bovine interferons-alpha suitable for immunopurification

Five murine hybridoma clones, producing monoclonal antibodies (MAbs) to bovine interferon-alpha (BoIFN-alpha) were established. One of these, F12, secreted MAbs giving high titers, in ELISA tests, neutralizing both BoIFN-alpha, -alpha C, and BoIFN-alpha D activities, belonging to the mouse IgG1 class, and having a binding affinity constant of 10(8) M-1. F12 MAbs were used for immunoaffinity purification of BoIFN-alpha, and recombinant BoIFN-alpha C from Escherichia coli extracts was purified to homogeneity in SDS-PAGE analysis and to a specific activity of 2 X 10(8) U/mg with 90% recovery of activity.

Typology of mood assessment curves by means of cluster analysis of computerized mathematical descriptions of time-series mood data collected from depressive inpatients treated with antidepressants

A recently developed method for the computerized description of mood curves was applied to self-evaluation mood data of a large sample of 136 depressive inpatients. The values of the mathematical parameters from this description were analysed by cluster analysis to determine different types of mood courses of patients undergoing therapy with antidepressants. In general, the most unfavorable type of mood course was overrepresented in the group of neurotic depressive patients, the most favorable one in the group of endogenous depressive patients. But in this latter diagnostic group, a remarkable proportion of patients with the unfavorable mood course was observed, indicating the well-known phenomenon of non-response to antidepressants. The results can be interpreted as a validation of the new method of computerized description of mood curves. This method might lead to interesting possibilities in drug treatment evaluation.

A non-linear mathematical model for computerized analysis of mood curves: construction of the model and its application to the mood curves of depressive and schizophrenic inpatients

A non-linear mathematical model for the computerized description of mood curves is presented. This model reaches a high goodness of fit to the real data and seems superior to a linear model recently proposed. Using this model in a computer program for describing the mood data of a large sample of psychiatric inpatients, significant and clinically meaningful group differences between the mood curves of schizophrenic, endogenous depressive, and neurotic depressive inpatients could be demonstrated. The application of this methodology might be helpful among others in the field of evaluative research.

A linear mathematical model for computerized analyses of mood curves. An empirical investigation on mood courses in depressive and schizophrenic inpatients

The repetitious measurement of actual mood alterations becomes more and more common in research oriented psychiatric departments. In this article a new method for the mathematical description and statistical evaluation of time series data is presented. This computerized approach is less restrictive than other procedures and seems to be very appropriate to the complex structure of time series. First results on mood courses of depressive and schizophrenic patients are presented to demonstrate the usefulness and validity of this new method.

Specific residues within an amino-terminal domain of 35 residues of interferon alpha are responsible for recognition of the human interferon alpha cell receptor and for triggering biological effects

Bovine interferon alpha C (IFN-alpha C) manifest at least 10(5)-fold lower antiviral activity on human cells than on bovine cells (Velan, B., Cohen, S., Grosfeld, H., Leitner, M., and Shafferman, A. (1985) J. Biol. Chem. 260, 5498-5504). By oligonucleotide site-directed mutagenesis within the coding region for the NH2-terminal 44-residue domain of BoIFN-alpha C, we replaced up to 18 residues by the corresponding HuIFN-alpha J1 residues. (HuIFN-alpha J1 is less than 60% homologous in sequence to BoIFN-alpha C.) The nine different bovine-human-IFN alpha hybrids obtained were compared to BoIFN-alpha C and HuIFN-alpha J1 with respect to their potential to induce an antiviral state, synthesis of 2-5A-synthetase, and their specific binding to human and bovine cells. Relative to BoIFN-alpha C, a gradual increase in biological activities (antiviral or 2-5A-synthetase) of approximately 10-, 10(2)-, 10(3)-, and approximately 10(4)-fold is obtained, depending on the number and positions of the residues substituted. A direct correlation exists between biological response and ability of IFN alpha to bind specifically to human cells. A BoIFN alpha molecule mutated in the 10-44 NH2-terminal domain was obtained which is 15, 8, and 35% as active as HuIFN-alpha J1 on human cells in specific binding, induction of antiviral, and 2-5A-synthetase activities, respectively. We concluded that at least 5 of the 12 residues at positions 10; 21, 22, 24; 27; 31, 34, 35, 37, 40; 42, 43 in the 10-44 NH2-terminal domain are critical for recognition of the human IFN-alpha cell receptor and for biological activity. These residues are found among 10 strictly conserved residues in all reported mammalian IFN alpha S, and they act in a cooperative manner to induce a biological response in human cells. The gap between the extent of improvement in binding capacity of the BoIFN alpha mutants on human cells and the corresponding biological response suggests that the primary signal of binding to the cell receptor is amplified within the cell. On bovine cells, HuIFN-alpha J1 and BoIFN-alpha C also compete for the same receptor, and it seems that at least part of the 10-44 NH2-terminal domain on IFN alpha is also involved in interaction with the bovine IFN alpha cell receptor.

Optimizing a nonlinear mathematical approach for the computerized analysis of mood curves

A nonlinear mathematical model for computerized description of mood curves is presented. This model reaches a high goodness of fit to the real data. It seems superior to two other models recently proposed. Using this model in a computer program for describing the mood data of a large sample of inpatients, significant and clinically meaningful group differences between the mood curves of schizophrenic, endogenous-depressive, and neurotic-depressive inpatients could be demonstrated. The application of the methodology might be helpful, e.g. in the field of evaluative research.

Priming immunization against cholera toxin and E. coli heat-labile toxin by a cholera toxin short peptide-beta-galactosidase hybrid synthesized in E. coli

A synthetic oligodeoxynucleotide encoding for a small peptide was employed for the expression of this peptide in a form suitable for immunization. The encoded peptide, namely, the region 50-64 of the B subunit of cholera toxin (CTP3), had previously been identified as a relevant epitope of cholera toxin. Thus, multiple immunizations with its conjugate to a protein carrier led to an efficient neutralizing response against native cholera toxin. Immunization with the resulting fusion protein of CTP3 and beta-galactosidase, followed by a booster injection of a sub-immunizing amount (1 microgram) of cholera toxin, led to a substantial level of neutralizing antibodies against both cholera toxin and the heat-labile toxin of Escherichia coli.

Bovine interferon alpha genes. Structure and expression

The bovine genome contains a gene family of interferon-alpha s (bIFN-alpha) that consists of at least five distinct members. Four of the bIFN-alpha genes isolated show a high degree of homology (97% in the nucleotide sequence and 93% in amino acid sequence). The overall homology in amino acid sequence of bIFN-alpha to human, murine, and rat IFNs-alpha is approximately 60%. Yet there are amino acid clusters (positions 28-41 and 118-146) which are highly conserved throughout the mammalian evolution and in which the overall homology can be as high as 86%. Within the C terminus conserved cluster there is a sequence containing 9 amino acids completely conserved in 16 mammalian IFNs-alpha and of these, 7 are also shared with a similar domain in some bacterial toxins, implying a common functional role for these domains. One of the genes, IFN-alpha C, was expressed in Escherichia coli. The purified bacterial IFN (specific activity, 2 X 10(8) units/mg) exhibited antiviral activity on bovine cells but no detectable activity was demonstrated on human and simian cells.

Identification by affinity labeling of potential sites in 23-S rRNA interacting with the 3' end of tRNA

A derivative of tRNAPhe carrying at its 3' end a photolyzable group was chemically synthesized by coupling p-azidobenzoylglycylhydrazide to periodate-oxidized tRNA. The reaction converts the 3'-terminal ribofuranoside residue into a six-membered ring. The binding of p-azidobenzoylglycylhydrazide-tRNA to 70-S ribosomes resembles the binding of Phe-tRNA in its requirement for poly(U) and Mg2+ dependence. Irradiation at wavelengths greater than 300 nm of complexes of p-azidobenzoylglycylhydrazide-tRNA and 70-S ribosomes results in the covalent binding of approximately 20% of the reversibly bound tRNA to the ribosomes. The labeling occurs predominantly at a single site in 23-S rRNA within the sequence included in the 18-S fragment. To identify the modified sequence, an RNase A digest of 23-S rRNA was fractionated on a hydrophobic matrix (Porapak Q) and adsorbed and non-adsorbed fractions were compared by fingerprint analysis. A relatively intense spot was observed in the expected region in the fingerprint of the adsorbed fraction. The presence of an unusual nucleotide in the sequence of this oligonucleotide was demonstrated by a mobility-shift analysis of a partial nuclease P1 digest. The sequence derived is G*-A-A-G-C (the asterisk denoting the site of modification). Sequences at six positions in the 23-S rRNA are compatible with the sequence of the oligonucleotide determined. Of the six positions five are located within nucleotides 1467-1887. This region of approximately 400 nucleotides is likely to include the sequence interacting with the 3' end of tRNA and possibly forming part of the peptidyl-transferase center.

The cardiovascular effects of dopamine in the severely asphyxiated neonate

The cardiovascular effects of dopamine were evaluated in 14 severely asphyxiated neonates. After a period of stabilization, either dopamine 2.5 micrograms/kg/minute or placebo was infused in a randomized double-blind protocol. In seven dopamine-treated infants, echocardiographically determined shortening fraction and mean velocity of circumferential fiber shortening increased when compared to preinfusion values (P less than 0.05). There was no significant change in these echo indices of cardiac function in the placebo-treated group. Systolic blood pressure rose in the dopamine group when compared to predopamine infusion values and to the postinfusion values of the placebo group (P less than 0.001 and 0.025, respectively). Diastolic blood pressure increased to a small degree in the dopamine group. There was no significant change in heart rate or echocardiographically measured systolic time intervals. Low doses of dopamine increase cardiac performance and raise systolic blood pressure in the severely asphyxiated neonate.

[Molybdocene dichloride as an antitumor agent (author's transl)]

The antitumor activity of molybdocene dichloride is tested against Ehrlich ascites tumor in CF1 mice. The application of 75 of 100 mg/kg 24 h after transplantation achieves 100% tumor inhibition until day 30. Following the d0 and d1 metallocene dichlorides of titanium and vanadium, molybdocene dichloride is the first analogous d2 system revealing similar antineoplastic properties.

[Double-contrast examination in hypotonia in the operated stomach (author's transl)]

The technique of examination, as well as the extent and quality of visualisation are described, basing on a selected case material of patients who had been subjected to stomach surgery; the extensive possibilities of diagnosis are studied. Hypotonia and double contrast offer considerable advantages over the conventional examination of the operated stomach. Assessment of mucosal conditions, especially in the anastomosis range, is facilitated, thus offering a chance to improve the method of diagnosis. Hypotonic double-contrast examination should always be performed if there are no possibilities of endoscopic examination.