Detection of false-negative results in nested primer PCR of proviral HIV-1 DNA

A control template for a competitive nested primer PCR of the HIV-1 gag region was constructed. This construct shares the primer recognition sequences with the wild-type template and yields a 97-bp fragment after amplification (wild-type: 115 bp). To provide an internal control for the individual PCR runs, six copies of this nested primer control plasmid were introduced into a reaction tube containing the specific sample (under the PCR conditions used, this copy number reproducibly gave a positive PCR signal). The results of our study show the feasibility of this concept by analyzing a plasmid (pBH10) containing HIV-1 wild-type sequences, and examination of samples from a cohort of HIV-1-seropositive subjects demonstrated the clinical usefulness of this test. The control plasmid was detectable in all of the samples but one, which without the use of the control template would have yielded a false-negative result.

Detection of tick-borne encephalitis virus by sample transfer, plaque assay and strand-specific reverse transcriptase polymerase chain reaction: what do we detect?

Experimental inoculation of mice provides a well characterized model for studying infection with tick-borne encephalitis virus (TBEV), a flavivirus pathogenic for humans. Conflicting data on the kinetics of viremia and the development of virus titers in the brain, however, were only recently shown to have resulted from the use of assay systems with different levels of sensitivity in the titration of TBEV, i.e. plaque assay or sample transfer into naive recipient mice. Theoretically, RT-PCR could extend further the detectability to antibody-neutralized virus and when undertaken strand-specifically discriminate active replication from the mere presence of TBEV. We have compared the conventional methods for detection of TBEV with a newly devised RT-PCR method. As expected, RT-PCR, in contrast to the infectivity assays, detected antibody-neutralized virus. Furthermore, the mere presence or active replication of the virus could be differentiated by strand-specific RT-PCR. Plaque assay and sample transfer, in contrast, both detected only infectious virus. However, whereas sample transfer provides higher sensitivity for detection of TBEV from solid organs, the plaque assay is less costly and considering animals welfare more convenient. Thus, the newly devised method may allow the resolution of unanswered questions, while both the traditional infectivity assays retain their benefits in certain situations.

Tumor uptake and metabolism of copper-67-labeled monoclonal antibody chCE7 in nude mice bearing neuroblastoma xenografts

METHODS

ChCE7, an internalizing, neuroblastoma-specific monoclonal antibody (MAb), and its F(ab')2 fragments were derived with the bifunctional ligand 4-(1,4,8,11-tetraazacyclotetradec-1-yl)-methyl benzoic acid tetrahydrochloride (CPTA) and labeled with the potential therapeutic nuclide 67Cu. After internalization and degradation of these immunoconjugates in SKN-AS human neuroblastoma cells, the terminal degradation product was found to be the lysine adduct of the copper complex. In vivo distributions in nude mice bearing neuroblastoma xenografts were studied and extracts from tumor and tissue samples were analyzed.

RESULTS

The intact MAb showed high tumor uptake, stable over 4 days postinjection (33.7% +/- 2.8% ID/g), with tumor/blood ratios increasing from 4.4 on Day 1 to 23.0 on Day 7 postinjection and low levels of radioactivity in other tissues. Analysis of tumor extracts by gel filtration chromatography and high-pressure liquid chromatography (HPLC) showed that over the period of 4 days radioactivity was present both in a high M(r) form, consisting of the MAb/antigen complex, as well as in a low M(r) form, consisting of the copper complex attached to short peptides, including the lys-CPTA complex. There was no evidence of aggregates or MAb/antigen complexes in the blood, radioactivity being exclusively in the form of intact MAb, and radioactivity in the liver was found to consist of intact MAb, MAb fragments and the lys-CPTA metabolite. In the case of the F(ab')2 fragments, high accumulation of radioactivity in the kidneys was observed and analysis of kidney extracts showed it to be due to rapid accumulation of the lys-CPTA complex. When kidney uptake and retention of the CPTA complex as well as of its lysine and glycine adducts was investigated, the lysine complex was taken up more strongly and retained longer in the kidneys than the other compounds.

CONCLUSION

Copper-67-labeled MAb chCE7 F(ab')2 fragments were prepared using a novel bifunctional copper ligand 1-(p-aminobenzyl)-1,4,7,10-tetraazacyclodecane-4,7,10-triacetate (DO3A). Compared with MAb-chCE7 F(ab')2 fragments labeled by the CPTA ligand, labels using the DO3A ligand showed improved biodistributions resulting, 48 hr postinjection, in a 4-fold increase in tumor uptake and a 4-fold reduction of radioactivity in the kidneys.

Quantitative multiple competitive PCR of HIV-1 DNA in a single reaction tube

A quantitative multiple competitive PCR (QMC-PCR) for determination of DNA copy numbers is described. Four competitive DNA templates for the env region of HIV-1 were constructed with sizes longer (187 and 163 bp) or shorter (122 and 105 bp) than the 142 bp of the wild-type PCR product. Varying amounts of each of these competitors are introduced together with the sample into a single reaction tube. Since competitors and wild-type fragments share the same primer recognition sequence (SK68/SK69), amplification occurs according to the rate of the introduced copy numbers. The PCR products are run on an agarose gel, and the copy number of the sample is determined by analyzing the bands with a video densitometer and calculating the equivalence point in a linear regression plot.

Single human T cells stimulated in the absence of feeder cells transcribe interleukin-2 and undergo long-term clonal growth in response to defined monoclonal antibodies and cytokine stimulation

The two-signal model of T-cell activation postulates that T lymphocytes require at least two distinct signals for activation. This model has been established with bulk cultures of T cells in which T-cell-T-cell interaction can occur, possibly delivering further unrecognized costimulatory signals. The signal requirements of single T cells for the induction of clonal cell growth or the transcription of cytokines would best be studied in a cell cloning system in the absence of feeder cells; however, such an experimental system has not been reported so far. In this study, we report the long-term cloning of human resting peripheral blood CD4+CD45RO- T cells under feeder cell-free conditions in response to CD3 and CD28 stimulation in the presence of exogenous interleukin-2 (IL-2). Cloning efficiency ranged from 40% to 60% depending on the presence of additional cytokines IL-1 and IL-6. Single-call polymerase chain reaction showed that transcription of IL-2 occurred in cells stimulated through CD3 plus CD28 alone. T cells grown in response to CD3 plus CD28 plus IL-2 stimulation produced both IL-4 and interferon-gamma (IFN-gamma) on restimulation (Th0 cells) and could be functionally differentiated into Th1- or Th2-type cells by the addition of IFN-gamma or IL-4, respectively, during cell cloning. These data show on the single-cell level a two-signal model of T- cell activation for the transcription of IL-2. In addition, these experiments show that IFN-gamma and IL-4 exert their T-cell-differentiating effects directly on the T cell without any further need for antigen-presenting cells. Together, our experiments show the feasability of a defined long-term clonal cell culture system to study the growth and differentiation of human T lymphocytes.

[Measurement of expired alcohol concentrations with a new electrochemical sensor. A model investigation to determine interference with volatile anesthetics and clinical application]

Absorption of irrigating fluid in transurethral prostatic resection (TURP) and percutaneous nephrolitholapaxy (PNL) into veins or delayed absorption due to fluid extravasation may result in a TURP syndrome. The measurement of end-tidal breath alcohol concentration (et AC) as a monitor of absorption of irrigating fluid labelled with 2% ethanol is limited by the disturbance of infrared sensors by volatile anaesthetics and nitrous oxide (N2O) (Fig. 2). An electrochemical sensor is acceptable for this method. The aim of the present study was the evaluation of breath alcohol measurements using an electrochemical sensor device (Alcomed 3010, Envitec). The stability of the sensor in the presence of volatile anaesthetics was examined using a lung model. In a clinical investigation, the device was then applied to spontaneously breathing or mechanically ventilated patients inhaling volatile anaesthetics during endoscopic urological surgery.

METHOD

A two-chamber lung model filled with water for performing noninvasive measurements at the mouth of a patient has already been introduced by Brunner et al. (Fig. 1). With the addition of different amounts of ethanol to the temperature-controlled water, a constant ethanol concentration is achievable in the air above the water that is dependent on adjustments of the ventilator. Increasing concentrations of volatile anaesthetics (isoflurane, enflurane, halothane, and sevoflurane) were added to the fresh gas flow (2 l O2/3 l N2O) and etACs were measured using the manually triggered self-absorbent electrochemical sensor. First, regression equations were established between breath alcohol concentrations and increased volatile anaesthetic concentrations. Regression equations were then established between end-tidal anaesthetic gas concentrations and vaporizer adjustments in order to rule out an influence of ethanol on the anaesthetic gas monitor Ultima V (Datex). In the clinical investigation, 53 intubated and ventilated patients (33 undergoing PNL, 20 undergoing TURP) and 48 patients breathing spontaneously (32 with inhalation anaesthesia, 16 with spinal anaesthesia) were investigated. The etAC was measured with the Alcomed 3010 and compared with gas-chromatographically registered blood alcohol concentrations (BAC). The study had previously been approved by the Ethical Committee of the Medical University of Luebeck. Patients with liver disease and a history of toxic abuse were excluded. Only one value per patient (maximum BAC) was included in the statistics in order to avoid a cluster effect.

RESULTS

The lung model experiments demonstrated that the measurement of etAC with an electrochemical sensor is free of interference by volatile anaesthetics (Table 1). The slope of the regression between the measured alcohol concentration and increased concentrations of anaesthetics did not differ significantly from baseline values. The measurement of end-tidal anaesthetic concentrations was not significantly different from vaporizer adjustments in the presence of increased alcohol concentrations (Table 2). During the clinical investigation, a regression between etAC and BAC was determined for both groups. For the group of patients breathing spontaneously, the correlation coefficient was 0.961 and the regression equation revealed etAC = 0.5677*BAC-0.1303 (Fig. 5). However, in the group of ventilated patients a biphasic course was shown that was dependent on BAC (Fig. 6). At BAC < 0.4%, a similar correlation (r = 0.856) to the spontaneously breathing group could be seen (regression equation: etAC = 0.617*BAC-0.020). Above 0.4% BAC there was no acceptable correlation (r = 0.444, regression equation: etAC = 0.202*BAC+0.104).

CONCLUSIONS

The tested electrochemical sensor does not interfere with volatile anaesthetics and N2O as demonstrated by a lung model. There is a good correlation between etAC and BAC measurements in patients breathing spontaneously with special regard to the slope of the regression (s = 0.57).

Allostimulated lymphocytes inhibit replication of HIV type 1

Previous reports demonstrated that alloantigen- or xenoantigen-specific antibodies displayed neutralizing activity toward human or simian immunodeficiency viruses. In the present article we have addressed the question of alloantigen-induced cell-mediated anti-HIV activity. We show that allostimulation resulted in a lymphocyte population (largely of the CD8-positive phenotype) with the capacity to inhibit HIV-1 replication in PHA blasts of homologous and, unexpectedly, also autologous origin. The allostimulated effector cells exerted their activity via a noncytolytic mechanism. Experiments in which direct cell-to-cell contact between allostimulated effectors and HIV-1-infected PHA blasts was prevented by a semipermeable membrane indicated that soluble mediators were involved in inhibition of HIV-1 replication. As such allostimulated effectors not only would have the capacity to prevent viral replication in allogeneic HIV-1-infected cells (known to play an important role in HIV-1 transmission in vivo), but also might inhibit HIV-1 growth in autologous lymphocytes, the concept of an AIDS vaccine containing both HIV-1 antigens and alloantigens warrants further consideration.

Effect of high- versus intermediate-purity blood coagulation factor concentrates on HIV-1 replication

Controversy exists as to whether treatment of HIV-1-seropositive hemophiliacs with blood coagulation products of high purity might help prevent the decline of CD4-positive lymphocytes and thus delay progression toward AIDS. As viral load has recently been shown to be associated with disease progression in HIV-1 infection, we tested for a possible direct interference of high- or intermediate-purity blood coagulation products with replication of HIV-1. The data obtained revealed comparable replication of HIV-1 in the presence and absence of all blood coagulation products tested (assessed by PCR-based quantitation of proviral HIV-1 DNA in infected cells after a 10-day incubation period). These data suggest that coagulation factor concentrates per se will also have no direct effect on HIV-1 replication in vivo.

A purine-rich sequence in the human BM-40 gene promoter region is a prerequisite for maximum transcription

BM-40 (osteonectin, SPARC [secreted protein, acidic, rich in cysteine]) is a highly conserved, matrix-associated protein that is found in basement membranes, bones and remodeling tissues throughout vertebrate evolution. We are reporting the characterization of the 5' end of the human BM-40 gene. Sequence comparison of the 5' region revealed significant homologies with the bovine and murine genes, including a purine-rich stretch composed of two boxes, GGA-box 1 and 2, separated by a pyrimidine-rich spacer element. Transfection analyses of the human BM-40 promoter provide strong evidence that this region comprises several distinct regulatory domains, to which different functions can be assigned. GGA-box 1 is thereby absolutely required and sufficient by itself for maximal BM-40 transcriptional activity, whereas the spacer element has a down-regulatory effect. Comparative transfection analyses in human cell lines, positive or negative for BM-40 transcripts, indicate that the GGA-box sequences in the human promoter, in contrast to the bovine promoter, do not significantly contribute to cell-type specific expression in human cells.

Interaction with human immunodeficiency virus type 1 modulates innate effector functions of human monocytes

The effect of human immunodeficiency virus (HIV) type 1 on human mononuclear phagocyte effector functions in response to infection with bacteria of the Mycobacterium avium-intracellular complex (MAC) was investigated. The results showed that interaction of HIV-1 or its constituents with CD4 expressed in the monocyte membrane led to substantial impairment of monocyte capacity to restrict the intracellular growth of MAC. This was accompanied by substantially decreased production of tumor necrosis factor-alpha by HIV-1-exposed and MAC-infected monocytes. However, productive HIV-1 infection of monocytes was not required to induce the observed effects. These studies suggest that HIV-1 may interfere with innate mononuclear phagocyte function. This may be of physiologic importance in the late stages of AIDS, when an impaired T cell immunity can no longer provide proper immune-activating signals, and may help to explain the undue susceptibility to MAC infections in these patients.

Growth of Candida albicans in normal and altered faecal flora in the model of continuous flow culture

We used the model of faecal microflora under continuous flow culture (CFC) conditions to study the growth of Candida albicans in mixed cultures. The development of Candida is usually limited by the high germ counts of aerobic and anaerobic bacteria. Candida growth in faecal flora could be obtained neither by the continuous inflow of C. albicans CFC monocultures nor by intermittent input of highly concentrated suspensions of C. albicans into the system. If the system was run under aerobic conditions development of C. albicans could be observed. After some days, however, the faecal flora again suppressed further development of the yeasts. Only marked destruction of the aerobic and anaerobic microflora by antibiotics resulted in growth or overgrowth of Candida albicans.

Genomic sequences and structural organization of the human nidogen gene (NID)

Nidogen/entactin is a ubiquitous 150-kDa multidomain basement membrane protein. Since in vitro binding studies indicated that nidogen may function as a major mediator in basement membrane organization and assembly, analysis of gene structure and regulation of gene expression will help us to understand many biological processes that involve degradation and reorganization of the basement membrane zone. An approximately 100-kb region of genomic DNA encoding the human nidogen gene (NID) including 5' and 3' flanking sequences has been cloned and characterized by restriction mapping and sequencing. The entire gene is more than 90 kb in length and contains 20 exons. All introns interrupt protein coding sequences. The size of individual introns varies significantly, ranging from 0.6 to 18 kb. Its exon/intron structure revealed that the protein domains of human nidogen are organized in a domain-specific manner with various subdomains being encoded by individual exons, indicating that exon duplication and shuffling have played an important role in determining the present structure of the protein. Comparison of the exon organization with the recently published ascidian nidogen amino acid sequence strongly suggests that vertebrate nidogen might have evolved from a common ancestral precursor resembling ascidian nidogen.

Development of a simple and selective separation of 67Cu from irradiated zinc for use in antibody labelling: a comparison of methods

A procedure for the production and separation of Cu isotopes from irradiated Zn was developed. Following a comparison of methods based on extraction, electrolysis and ion-exchange chromatography, a technique for the separation of Cu employing three ion-exchange matrices was developed which was simple, reproducible and hot cell-compatible. The specific activity of the final product was 37 MBq 67Cu/microgram Cu at EOB. The level of impurities was so low that no interference with antibody labelling was observed.

Intra-species characterization of clinical isolates and biotechnologically used strains of Lactobacillus rhamnosus by analysis of the total soluble cytoplasmatic proteins with silver staining

Lactobacillus rhamnosus is often used in milk products because of its technological properties, however it is supposed to be related to human infections as well. Therefore, 23 L. rhamnosus strains, including the type strain, were investigated. Nine strains resulted from biotechnological sources, 14 isolates had a clinical background, 13 came from a swedish culture collection. Biochemical and physiological properties were proved by classical tests. Analysis of the total soluble cytoplasmatic protein patterns was performed with diamine silver staining, a technique not previously applied to lactobacilli. Classical tests were able to confirm all strains as L. rhamnosus. Analysis of protein patterns allowed to differentiate between three clusters. Cluster I contained the type strain and biotechnologically used strains and one clinical strain isolated in Berlin. The second consisted of both, technological and clinical strains. The third cluster contained clinical isolates alone. SDS-PAGE of proteins together with diamine silver staining seems to be helpful to detect intra-species differences. It was stated, that technologically used strains of L. rhamnosus could clearly be differentiated from each other and also from clinical isolates.

[Growth of Candida albicans in normal and altered fecal flora in the continuous flow culture model]

We used the model of fecal microflora under continuous flow culture (cfc) conditions to study the growth of Candida albicans in mixed cultures. The development of Candida is usually limited by the high germ counts of aerobic and anaerobic bacteria. Neither by the continuous inflow of C. albicans-cfc-monocultures nor by intermittent input of highly concentrated suspensions of C. albicans into the system a growth in fecal flora could be obtained. If the system was run under aerobic conditions a development of C. albicans with few hyphal growth could be observed. After some days however, the fecal flora again suppressed a further development of the yeasts. Only a marked destruction of the aerobic and anaerobic microflora by antibiotics resulted in a growth or overgrowth of Candida albicans.

Binding properties and protease stability of recombinant human nidogen

Recombinant human nidogen was obtained from transfected kidney cell clones as a 150-kDa protein with a three-globule structure. It was modified by sulfation and O-glycosylation and a lower level of N-glycosylation than mouse nidogen. Recombinant nidogens of both species were, however, indistinguishable in their affinities for laminin-1 and a recombinant laminin gamma 1 chain fragment and showed a similar binding to collagen IV and the heparan sulfate proteoglycan perlecan. The two nidogens were also equivalent in the promotion of ternary complex formation between these ligands, indicating that this function has been conserved during mammalian evolution. Fewer zinc-binding sites could be identified in human nidogen and correlated with a lower capacity of zinc to prevent binding to laminin and collagen IV. Most remarkable was the greater sensitivity of human nidogen to endogenous proteolysis in cell culture, yielding fragments of 90-145 kDa. Studies with several exogenous proteases, including thrombin and leucocyte elastase, showed lack of stability of the N-terminal globular domain G1 in contrast to what was found for mouse nidogen. Since such degradation could be important for basement membrane remodelling, this difference between human and mouse may be biologically significant.

Cellular processing of copper-67-labeled monoclonal antibody chCE7 by human neuroblastoma cells

Monoclonal antibody chCE7, an internalizing neuroblastoma-specific chimeric antibody, was derivatized with the macrocyclic amine ligand 4-[(1,4,8,11-tetraazacyclotetradec-1-yl)-methyl] benzoic acid tetrahydrochloride and labeled with the potential therapeutic nuclide 67Cu. Using pulse labeling and an acid elution endocytosis assay, 67Cu-chCE7 was found to be internalized into human neuroblastoma (SKN-AS) cells at a similar rate and to a similar extent as 125I-labeled chCE7. Uptake of 67Cu-chCE7 and 125I-chCE7 into the acid stable (intracellular) pool proceeded with similar kinetics during the first 2 h of internalization. However, in contrast to 125I-chCE7-loaded cells, at later times intracellular radioactivity kept increasing in the case of 67Cu-chCE7-loaded cells. It was shown that this effect is due to the intracellular accumulation of a low M(r) degradation product consisting of the 67Cu-4[(1,4,8,11-tetraazacyclotetradec-1-yl)-methyl] benzoic acid complex, possibly with a short peptide attached to it. Degradation of both 125I-chCE7 and 67Cu-chCE7 was inhibited by chloroquine, indicating endosomal or lysosomal degradation, and a 43,000 M(r) fragment was found to be the major high M(r) degradation product in both cases. Although at times between 4 and 6 h of internalization intracellular breakdown of 67Cu-chCE7 was found to proceed more slowly, the major difference between the two immunoconjugates resides in the prolonged cellular retention of the 67Cu-chCE7 metabolite.

When awaiting 'Bio' Champollion: dynamic programming regularization of the protein secondary structure predictions

Predictions of protein secondary structure using current methods are often unrealistic, i.e. the predicted alpha-helices or beta-strands are too short. To improve the realism, various heuristic 'filtering' or 'smoothing' methods are used. They are more or less intuitive and are based on ad hoc corrections. We present a regularization method to obtain a realistic secondary structure from predicted propensities. It is based on the known dynamic programming algorithm and is quite objective. It can be used with any prediction method which yields propensities. The regularized predictions conserve well the overall prediction accuracy and improve the 'protein-likeness' of the prediction.

[Protein fingerprinting as a method for strain-specific differentiation of technologically useful Lactobacillus strains from clinical isolates]

Lactobacilli are often used in products of animal origin because of their technological properties and as protective cultures against pathogenic microorganisms, however they are supposed to be related to human infections as well. Therefore 39 strains of species that are in biotechnological usage, including the type strains, and some clinical isolates were investigated. 9 strains of L. acidophilus, 7 of L. gasseri and 23 strains of L. rhamnosus were tested. Biochemical and physiological properties were proved by classical tests. Analysis of the total soluble cytoplasmatic protein patterns was performed with diamine silver staining, a technique not previously applied to lactobacilli. Classical tests were able to confirm all strains as belonging to one of the three species. Analysis of protein patterns allowed to differentiate between strains of the same species. In case of L. acidophilus biotechnologically used strains and clinical isolates were clustered separately. L. rhamnosus formed three clusters. SDS-PAGE of proteins together with diamine silver staining seems to be helpful to detect intra-species differences. It was stated, that technologically used strains of lactobacilli could clearly be differentiated from another and also from clinical isolates.

Lipoprotein-associated paf (LA-paf) was found in washed human platelets and monocyte/macrophage-like U937 cells

Beyond cholesterol, inflammatory ether phospholipids such as platelet-activating factor (paf) may play a role in atherogenesis. (1) We detected a paf-like compound ('LA-paf') associated with human serum lipoproteins, mainly in LDL but not with the lipoprotein-poor fraction. (2) LA-paf was also found in washed human platelets, from where it was partially released during platelet aggregation in response to paf (50 nM) or thrombin (1 U). In addition, resident monocyte/macrophage-like U937 cells carried huge amounts of LA-paf (41 ng per 10(7) cells) and metabolized added [3H]paf to a labelled compound co-eluting with the retention time of LA-paf in standard HPLC. (3) Functionally, LA-paf had a comparable potency to synthetic paf, because LA-paf aggregated washed aspirin-treated platelets in a concentration-dependent manner. The specific paf receptor antagonist WEB2086 inhibited the platelet aggregation induced by three distinct LA-paf preparations as compared with synthetic paf with similar inhibitory concentrations (IC50: 35.6 +/- 12.8, 24.0 +/- 4.0, 38.0 +/- 15.8 nM for LA-paf, and 43.6 +/- 6.5 nM for synthetic paf), indicating that LA-paf interacted with paf receptors. (4) However, LA-paf had a distinct retention time using high-pressure liquid chromatography (HPLC) as compared with synthetic paf. LA-paf eluted at 9-15 min and synthetic paf at 21-24 min. In addition, total and non-specific [3H]paf binding to intact washed human platelets was affected differently by the two unlabelled agonists: while LA-paf increased total and non-specific (but not specific) binding in a significant manner (P < 0.002 and P < 0.007) as LDL did (P < 0.006 and P < 0.03), synthetic paf decreased total binding (P < 0.03). Similarly, low-density lipoproteins (LDL) increased significantly the total [3H]paf binding. In contrast, paf did not affect specific [125I]LDL binding to human fibroblasts. Our results show the presence of LA-paf in lipoproteins, washed human platelets and monocyte/macrophage-like cells. As LDL and LA-paf purified from the same LDL particles increased significantly the total [3H]paf binding to intact human platelets, it might modulate platelet adherence to vascular endothelial cells.

Constitutive expression of chimeric neo-Rev response element transcripts suppresses HIV-1 replication in human CD4+ T lymphocytes

We have previously reported that chimeric neomycin phosphotransferase (neo)-Rev response element (RRE) transcripts suppress the function of the human immunodeficiency virus type 1 (HIV-1) Rev trans-activator protein in HeLa cells. In an extension of these experiments, human CD4+ CEM cells (G418-resistant cell populations and clonal isolates) stably expressing chimeric neo-RRE genes (2, 3, or 6 RRE copies) were generated using retroviral-mediated gene transfer. The transduced CEM clones were infected with the HIV-1 HTLVIIIB isolate and the following three phenotypes were observed: (i) the transduced CEM cells were readily infected with HIV-1 indistinguishable from the control CEM cells; (ii) the appearance of HIV-1 replication markers was significantly delayed; (iii) no signs of HIV-1 replication were detectable although proviral HIV-1 DNA sequences could be detected in these cells. Furthermore, HIV antigen expression was limited in neo-resistant CEM cell populations inoculated with the HIV-1 HTLVIIIB isolate. Only 10% of the CEM-pX17-3xRRE cells and 20% of the CEM-pX17-2xRRE cells displayed HIV-1 antigens 43 days after challenge and had retained CD4 surface expression on 47% and 64% of the cells, respectively. In sharp contrast, 80% of the CEM-pX17 or the CEM-pX17-6xRRE cells expressed HIV-1 antigens but no CD4 antigens were detectable in these cultures. These results clearly indicate that RRE decoys could be developed into an effective somatic gene therapy approach against HIV-1 induced acquired immunodeficiency syndrome (AIDS).

Technique for training schizophrenic patients in illness self-management: a controlled trial

OBJECTIVE

To determine whether schizophrenic outpatients receiving low-dose neuroleptic therapy could learn and retain complex information and skills related to self-management of their illness, a novel technique of teaching, using cognitive and behavioral methods, was designed to compensate for the patients' learning disabilities.

METHOD

The subjects were 41 patients with DSM-III-R schizophrenia who were receiving constant maintenance neuroleptic drug therapy. They were randomly assigned to structured, modularized skills training or to supportive group psychotherapy.

RESULTS

The patients who received skills training made significant gains in each of the areas taught, while those participating in group therapy did not. The skills learned during training were retained without significant erosion over a 1-year follow-up period.

CONCLUSIONS

The effectiveness of modularized teaching of illness self-management skills to schizophrenic patients appears to be largely independent of baseline psychology and symptom improvement. Such an approach is useful for overcoming or compensating for the enduring cognitive and information processing deficits commonly found in schizophrenia.

Neural development

The FESN-sponsored follow-up meeting on neural development highlighted progress toward understanding several central issues in developmental neurobiology with particular emphasis on investigation into the mechanisms of cell fate determination. In systems as diverse as the HSN neurons of C. elegans, the photoreceptor cells of the Drosophila eye, the wide range of cell types within the vertebrate retina and the neurons of the cerebral cortex, hindbrain and spinal cord, the importance of environment in the determination and maintenance of cell fate was clearly established. Advances in cell marking techniques, including fluorescent dye and retroviral tagging, have enabled the fates of cells in normal and heterotypic environments to be followed and have demonstrated the initial plasticity of the progenitor cell population in many systems. The recent establishment of in vitro systems for studying neural development should further define the precise nature and identity of the environmental signals that act to establish and maintain cell fate. Of course, establishment of cell identity is only the initial phase in the formation of the mature nervous system. Once the fate of individual cells is determined, migration of cells to appropriate locations, extension of axons to appropriate targets and refinement of neuronal circuitry must occur. Both the definition of genes that influence these processes in nematodes and recent advances in imaging techniques that provide a means of observing these later, dynamic processes in 'living' brain slices promise to significantly advance understanding of the complexities of development of functional nervous systems.

Expression of chimeric neo-Rev response element sequences interferes with Rev-dependent HIV-1 Gag expression

Recombinant plasmids containing reiterated human immunodeficiency virus type 1 (HIV-1) Rev response element (RRE) sequences were constructed to suppress Rev-dependent HIV-1 Gag expression. The mammalian expression vectors pMAMneo containing one, three, or six repeats of the RRE sequence were cotransfected with a HIV-1 HTLV-IIIB proviral DNA into HeLa cells. All three RRE expression plasmids reduced replication of HIV-1 with similar efficacy. Furthermore, the chimeric expression vector pCMV neoRRE6 x ----(containing six copies of the RRE sequence) was used to establish HeLa cell lines constitutively expressing RRE. A plasmid encoding a Rev-dependent HIV-1 p24 Gag protein was cotransfected with the wild-type Rev expression plasmid into three different RRE-expressing HeLa cell lines. p24 Gag protein production in the culture supernatants of the HeLaneoRRE cells was compared with two neo-expressing cell lines. Although all cell lines (HeLaneoRRE, HeLaneo) displayed similar transfection efficiencies, p24 Gag protein synthesis was markedly reduced in the RRE-expressing cell lines in comparison to the control cells.

Formation of new muscle fibres and tumours after injection of cultured myogenic cells

We examined the effects of implantation of cultured myogenic cells from a permanent cell line into soleus muscles of histocompatible adult mice. Myogenic cells (10(6) or 10(4)) were implanted into intact muscles, muscles frozen with liquid nitrogen, paralysed with botulinum toxin or reinnervated after long-term (seven months) denervation. Formation of numerous muscle fibres in myogenic cell-injected muscles raised the total number of fibres up to ten times above control by four weeks. Larger effects were found in freeze-damaged than in paralysed muscles. The new fibres had small calibers, considerable length (greater than 1.3 mm, maximum distance over which serial sections were made), were multinucleated and were oriented parallel to the large-diameter fibres of the host muscles. In some experiments beta-galactosidase, introduced into myogenic cells via retroviral transfection, was detected in small and large muscle fibres 4-20 weeks after implantation, indicating survival of the grafted cells and formation of mosaic (host-donor) and new fibres of donor origin. Muscle weight increased significantly and, rather surprisingly, a parallel increase was found in isometric tetanic tension of isolated nerve-muscle preparations; thus tension per mg muscle tissue was not different from normal. By eight weeks reduction of acetylcholine sensitivity and down-regulation of neural cell adhesion molecule to normal were observed, indicating that synaptic transmission at the new fibres was mature. After different periods of time (5-20 weeks, depending on the subclone used) tumours developed in most but not all injected limbs (37 out of 39). The tumours were destructive to the muscles and were classified as rhabdomyosarcomas. Prior to tumour formation, neural cell adhesion molecule positive cells reappeared in the muscles; since the myogenic cells initially produced differentiated muscle fibres, it appears that malignant growth is induced by factors in vivo. Thus, at present the outcome of such implantation is unpredictable.

trans-activation of the HIV-1 LTR by the HIV-1 Tat and HTLV-I Tax proteins is mediated by different cis-acting sequences

Human immunodeficiency virus type 1 (HIV-1) gene expression is regulated by viral and cellular factors interacting with cis-elements located in the retroviral long terminal repeat (LTR). In this report we analyzed HIV-1 LTR-specific regulatory sequences responsive to the HIV-1 Tat and HTLV-I Tax trans-activator proteins. Our results indicate that the Sp1 binding sites in the HIV-1 LTR are crucially involved in Tat-mediated gene expression in human Jurkat T-cells whereas they are dispensable for HTLV-I Tax-induced activation. In contrast, the NF-kB binding sites within the HIV-1 LTR are essential for Tax-mediated transcription but had only marginal effect on Tat-induced reporter gene expression.

[The categorization of mandibular growth potential by Petrovic, Lavergne and Stutzmann]

The results of the study show whether the classification of mandibular growth potential, as proposed by Petrovic, Lavergne and Stutzmann has any influence on the treatment with a function regulator. X-rays of 140 class II patients were analysed after a treatment time of approximately 2 years. In comparison with 133 class II children without any treatment, a significant increase of mandibular length was observed in almost all children treated. There was no significant difference in the increase of mandibular length between category 2 (low growth potential) and category 5 (high growth potential).

Heterogenic mRNAs with an identical protein-coding region of the human embryonic myosin alkali light chain in skeletal muscle cells

The formation of human myotubes in culture is accompanied by the induction of developmentally regulated, muscle-specific genes. We have studied the expression of human myosin light chain proteins and mRNAs during myogenesis in culture, in particular the skeletal embryonic myosin light chain 1 (MC1emb), which is indistinguishable from MLC1 of adult atrial cardiac muscle (MLC1A) as has been shown for rodent and bovine MLC1emb. We have identified distinct MLC1emb/MLC1A mRNAs in cultured human skeletal muscle cells that differ in their 5' and 3' untranslated regions but contain identical protein-coding regions. The alternative 3' untranslated region is detectable also in RNA of human atria. The different MLC1emb RNAs are likely to be encoded by one gene. It appears that the two MLC1emb 5' untranslated regions of the human gene are specific for man. In the mouse, only one 5' untranslated region of the MLC1emb gene has been detected.

Nephrogenic adenoma of the bladder: urographic spectrum

Nephrogenic adenoma is a rare, proliferative response of urothelium to urinary infection or injury of the bladder mucosa. Histologically, the lesion resembles proximal tubules of the nephron. While it can occur throughout the urinary tract, it usually appears in the bladder, with diverse radiographic manifestations. Of 6 patients with nephrogenic adenoma of the bladder, 3 presented with masses in the bladder and 2 with irregularities of the bladder mucosa on urography, while 1 showed no focal urographic abnormalities. There were no distinctive radiographic features of nephrogenic adenoma that would allow it to be differentiated from tumor or other inflammatory lesions. Although it is considered benign, bladder involvement may be extensive and eradication of the tumor may be difficult.

Regulated expression of nuclear protein(s) in myogenic cells that binds to a conserved 3' untranslated region in pro alpha 1 (I) collagen cDNA

We describe the identification and DNA-binding properties of nuclear proteins from rat L6 myoblasts which recognize an interspecies conserved 3' untranslated segment of pro alpha 1 (I) collagen cDNA. Levels of the two pro alpha 1 (I) collagen RNAs, present in L6 myoblasts, decreased drastically between 54 and 75 h after induction of myotube formation in serum-free medium. Both mRNAs contained a conserved sequence segment of 135 nucleotides (termed tame sequence) in the 3' untranslated region that had 96% homology to the human and murine pro alpha 1 (I) collagen genes. The cDNA of this tame sequence was specifically recognized by nuclear protein(s) from L6 myoblasts, as judged by gel retardation assays and DNase I footprints. The tame-binding protein(s) was able to recognize its target sequence on double-stranded DNA but bound also to the appropriate single-stranded oligonucleotide. Protein that bound to the tame sequence was undetectable in nuclear extracts of L6 myotubes that did not accumulate the two collagen mRNAs. Therefore, the activity of this nuclear protein seems to be linked to accumulation of the sequences that it recognizes in vitro. The collagen RNAs and the nuclear tame-binding proteins reappeared after a change of medium, which further suggests that the RNAs and the protein(s) are coordinately regulated.

Lymphocyte antigen Leu-19 as a molecular marker of regeneration in human skeletal muscle

Antigen Leu-19 (Leu19-Ag), a 200- to 220-kDa surface glycoprotein, was originally identified on a subset of human peripheral lymphocytes exhibiting non-major histocompatibility complex-restricted cytotoxicity. Here we report that monoclonal antibody Leu-19 (mAb-Leu19) labels structures in human skeletal muscle: (i) satellite cells, which form the stem cell pool of muscle fiber regeneration, both in normal and diseased muscle; (ii) myotubes and myotube projections in regions of muscle fiber repair; (iii) periodically organized fibrillar structures in areas of regeneration; (iv) the surface of myoblasts and developing myotubes in culture. mAb-Leu19 precipitated a protein of approximately 200 kDa from cultured muscle cells. Our data show that Leu19-Ag is expressed on muscle-specific components of myosegments in repair and thus represents a molecular marker of muscle regeneration. On the basis of this molecular marker and using laser scan microscopy, it is possible to visualize at the light microscopic level hitherto undetectable details of muscle regeneration in routine cryostat sections.

Localization of the putative precursor of Alzheimer's disease-specific amyloid at nuclear envelopes of adult human muscle

Cloning and sequence analysis revealed the putative amyloid A4 precursor (pre-A4) of Alzheimer's disease to have characteristics of a membrane-spanning glycoprotein. In addition to brain, pre-A4 mRNA was found in adult human muscle and other tissues. We demonstrate by in situ hybridization that pre-A4 mRNA is present in adult human muscle, in cultured human myoblasts and myotubes. Immunofluorescence with antipeptide antibodies shows the putative pre-A4 protein to be expressed in adult human muscle and associated with some but not all nuclear envelopes. Despite high levels of a single 3.5-kb pre-A4 mRNA species in cultured myoblasts and myotubes, the presence of putative pre-A4 protein could not be detected by immunofluorescence. This suggests that putative pre-A4 protein is stabilized and therefore functioning in the innervated muscle tissue but not in developing, i.e. non-innervated cultured muscle cells. The selective localization of the protein on distinct nuclear envelopes could reflect an interaction with motor endplates.

Magnetic resonance imaging in children suffering from spina bifida

22 children with myelomeningocele (MMC) were examined by magnetic resonance imaging (MRI). After operative closure a tethered cord was found in 78% of the patients. A primary tethered cord was detected in all patients where a lipomyelomeningocele had not been operated on yet. Additional malformations shown by MRI were hydromyelia and diastematomyelia. No correlation could be found between the degree of morphologic changes and the clinical course. In covered MMCs, MRI investigation is recommended as method of choice before operation. After operative closure a control-MRI should be performed after three months. If there are no pathological findings, further follow-up should be done by ultrasound investigation twice a year.

[Diabetes mellitus in advanced age. 7. Kidney function and behavior of blood pressure in long-term diabetic patients in the Newbrandenburg district]

Only 5.84 per cent of the 19,968 diabetics of the district Neubrandenburg had a diabetes duration of 15 and crore years (long term diabetics) in 1982. 44.9 per cent of these long term diabetics showed increased serum Oeatinine values and 54.7 per cent a hypertonia, where the fracture of each of these pathological influence parameters rose in conformability of the age. The frequency of hypertonia grew with rising serum creatinine value. The role of hypertonia for the excess mortality of the long term diabetics is well proved, where a persistent hypertonia possibly accelerates the renal failure stronger than a no more settled metabolism as it occurs in this group of patients. The high frequency of hypertonia values of blood pressure with the long term diabetics of a country district lets expect existing reserves in reading an improve of prognosis by optimizing the methods of antihypertensive therapy.

Laser-induced fusion of mammalian cells and plant protoplasts

An ultraviolet-laser microbeam was shown to be suitable for inducing fusion of individually selected plant protoplasts or of B-lymphocytes with myeloma cells. The fusion took place in normal culture medium and the fusogenic condition perturbed the cells only for a fraction of a millisecond. Without manipulating the cell culture except for exposing the cells to laser light, fusion products between preselected individual pairs may be produced.

[Kidney function and behavior of blood pressure in short-term diabetic patients. A follow-up study 1982-1986]

In 1982 there were increased creatinine values in 24.9 per cent (n = 344) of 1,380 investigated short-term diabetics of a closed territory. The course of disease of these 344 cases was followed in a follow-up-study. None of the patients had come to dialysis treatment. 32.3 per cent had died until 1986. In no case uremia caused the death. Hypertonias had a significant higher creatinine level than normotoniacs. The creatinine rise was on a higher level with the hypertoniacs. In 1982 the frequency of hypertension in the group of the died patients was with 65.8 per cent significant higher than in the group of the 1986 still living patients (32.9 per cent).

[Diagnostic value of alpha 1-acid glycoprotein in the cerebrospinal fluid]

Samples from 1415 neurological patients were used to study the diagnostic value of acid alpha 1-glycoprotein in the lumbar cerebrospinal fluid. The value of analysis for this substance is considered to lie in the detection of non-specific acute-phase reactions of various causes in the CNS with special reference to barrier problems. The large number of pathologically elevated values associated with acute inflammations of the meninges and cerebral parenchyme is particularly striking. The results of the studies are analyzed on the basis of comprehensive control investigations (n = 559).

[Kidney function, blood pressure and weight behavior in long-term diabetic patients]

All long-term diabetics (1,108 cases) of the district Neubrandenburg were investigated in a cross-section study and compared with a non-diabetic population. Long-term diabetics were significantly more frequently suffering from renal insufficiency (44.9%) and hypertension (54.7%) but they were more rarely obese than nondiabetics. A clearly positive correlation existed in the two groups between hypertension and renal insufficiency as well as between obesity and hypertension. With growing age the proportion of long-term diabetics suffering from renal insufficiency and hypertension increased. The treatment of hypertension must be regarded as highly important in the care of diabetics.

[Vipoma. 9-year observations using currently available therapy methods]

A now 61-year old man with hypersecretion of vasoactive intestinal polypeptide (VIP) due to carcinoma of the tail of the pancreas was treated and followed for nine years. Combined administration of lomustin (2.5 mg/kg on day 1) and 5-fluorouracil (30 mg/kg on days 2-6) over eight courses at six-week intervals achieved clinical remission for 13 months. No clinical improvement was observed with streptozocin (500 mg/m2 on days 1-5) for two courses four weeks apart. Treatment had to be discontinued after the second course because of the onset of (rarely observed) neurotoxic side-effect of bilateral peroneal paresis. High doses of somatostatin (6.9 micrograms/kg hourly intravenously) immediately and markedly reduced stool quantity. But at a lower dose (3.4 micrograms/kg hourly i.v.) there was no noticeable effect. In the further course of the disease, massive attacks of diarrhoea at varying intervals were best controlled in intensity and duration by prednisolone (50-60 mg daily). Other drugs which have been recommended for such cases (indometacin, lithium, trifluoperazine, nicotinic acid and clonidine) had no worth-while effect. In future long-acting somatostatin analogues may provide better prospects for long-term treatment.