Culture of vibrating microtome tissue slices as a 3D model in biomedical research

The basic idea behind the use of 3-dimensional (3D) tools in biomedical research is the assumption that the structures under study will perform at the best in vitro if cultivated in an environment that is as similar as possible to their natural in vivo embedding. Tissue slicing fulfills this premise optimally: it is an accessible, unexpensive, imaging-friendly, and technically rather simple procedure which largely preserves the extracellular matrix and includes all or at least most supportive cell types in the correct tissue architecture with little cellular damage. Vibrating microtomes (vibratomes) can further improve the quality of the generated slices because of the lateral, saw-like movement of the blade, which significantly reduces tissue pulling or tearing compared to a straight cut. In spite of its obvious advantages, vibrating microtome slices are rather underrepresented in the current discussion on 3D tools, which is dominated by methods as organoids, organ-on-chip and bioprinting. Here, we review the development of vibrating microtome tissue slices, the major technical features underlying its application, as well as its current use and potential advances, such as a combination with novel microfluidic culture chambers. Once fully integrated into the 3D toolbox, tissue slices may significantly contribute to decrease the use of laboratory animals and is likely to have a strong impact on basic and translational research as well as drug screening.

Herpesvirus saimiri pathogenicity enhanced by thymidine kinase of herpes simplex virus

Herpesvirus saimiri can be used as an efficient gene expression vector for human T lymphocytes and thus may allow applications in experimental leukemia therapy. We constructed recombinant viruses for the functional expression of the thymidine kinase (TK) of herpes simplex virus type 1 (HSV) as a suicide gene. These viruses reliably allowed the targeted elimination of transduced nonpermissive human T cells in vitro after the administration of ganciclovir. To test the reliability of this function under the most stringent permissive conditions, in this study we analyzed the influence of the prodrugs ganciclovir and acyclovir in common marmosets on the acute leukemogenesis induced by either wild-type herpesvirus saimiri C488 or by a recombinant derivative expressing TK of HSV. Antiviral drug treatment did not influence the rapid development of acute disease. In contrast, the presence of the HSV tk gene resulted in a faster disease progression. In addition, HSV TK-expressing viruses showed faster replication than wild-type virus in culture at low serum concentrations. Thus, HSV TK accelerates the replication of herpesvirus saimiri and enhances its pathogenicity. This should be generally considered when HSV TK is applied as a transgene in replication-competent DNA virus vectors for gene therapy.

Functional long-term thymidine kinase suicide gene expression in human T cells using a herpesvirus saimiri vector

Herpesvirus saimiri transforms human T lymphocytes to stable growth and persists episomally without genomic integration and without virus production. The transformed T cells retain essential features of their parental cells including the MHC-restricted antigen specificity which may be useful for applications in adoptive immunotherapy. In order to improve the biological safety of such vectors, the prodrug activating gene thymidine kinase of herpes simplex virus was inserted into the genome of herpesvirus saimiri by homologous recombination. After infection with wild-type or cloned recombinant viruses, T cells from tamarin monkeys and from humans were transformed to stable growth. Thymidine kinase-expressing transformed T cells were efficiently eliminated in the presence of low concentrations of ganciclovir. This elimination mechanism remained fully functional over an observation period of 12 months. The potentially immunogenic neomycin resistance gene expression cassette was deleted from the genome of established mutant viruses by using the prokaryotic Cre/LoxP recombination system. At any time during the course of a therapeutic application, thymidine kinase-expressing transformed human T cells might be eliminated after administration of ganciclovir. In principle, this function could be useful for the T cell-dependent immunotherapy of resistant blood cancer while avoiding the risk of uncontrolled graft-versus-host disease.

RigFit: a new approach to superimposing ligand molecules

If structural knowledge of a receptor under consideration is lacking, drug design approaches focus on similarity or dissimilarity analysis of putative ligands. In this context the mutual ligand superposition is of utmost importance. Methods that are rapid enough to facilitate interactive usage, that allow to process sets of conformers and that enable database screening are of special interest here. The ability to superpose molecular fragments instead of entire molecules has proven to be helpful too. The RIGFIT approach meets these requirements and has several additional advantages. In three distinct test applications, we evaluated how closely we can approximate the observed relative orientation for a set of known crystal structures, we employed RIGFIT as a fragment placement procedure, and we performed a fragment-based database screening. The run time of RIGFIT can be traded off against its accuracy. To be competitive in accuracy with another state-of-the-art alignment tool, with which we compare our method explicitly, computing times of about 6 s per superposition on a common day workstation are required. If longer run times can be afforded the accuracy increases significantly. RIGFIT is part of the flexible superposition software FLEXS which can be accessed on the WWW [http:/(/)cartan.gmd.de/FlexS].

The interleukin-17 gene of herpesvirus saimiri

In comparison to wild-type herpesvirus saimiri, viral interleukin-17 gene knockout mutants have unaltered behavior regarding viral replication, T-cell transformation in vitro, and pathogenicity in cottontop tamarins. Thus, this gene is not required for T-cell lymphoma induction but may contribute to apathogenic viral persistence in the natural host, the squirrel monkey.

T-cell lymphoma caused by herpesvirus saimiri C488 independently of ie14/vsag, a viral gene with superantigen homology

The immediate-early gene ie14/vsag of herpesvirus saimiri has homology with murine superantigens. We compared the pathogenesis of infection with either ie14/vsag deletion mutants or wild-type virus C488 in cottontop tamarin monkeys (Saguinus oedipus). Two weeks after infection, all animals developed acute T-cell lymphomas independently of the presence of the viral ie14/vsag gene.

The superantigen-homologous viral immediate-early gene ie14/vsag in herpesvirus saimiri-transformed human T cells

Herpesvirus saimiri C488 transforms human T lymphocytes to stable growth in culture. The growth-transformed human T cells harbor the viral genome in a nonintegrated episomal form without production of virus particles. In these cells, virus gene expression was previously found to be confined to the transforming genes stpC and tip. In order to analyze virus gene expression in more detail, we applied a subtractive hybridization technique and compared stimulated virus-transformed cells with uninfected parental T cells of the same donor. A number of known T-cell activation genes were isolated. Viral stpC/tip cDNAs were enriched after subtraction. In addition, the viral immediate-early, superantigen-homologous gene ie14/vsag was represented by numerous cDNA clones that comprised the entire spliced transcript. Whereas a weak basal expression of ie14/vsag was detected by reverse transcription-PCR only, the phorbol ester-induced transcripts were readily shown by Northern blotting. ie14/vsag, which before had been classified as a major immediate-early gene of herpesvirus saimiri, is localized within a highly conserved region with extensive homologies to the cellular genome. Mutant viruses without the ie14/vsag gene are replication competent and fully capable of transforming human and marmoset T cells. Since ie14/vsag is transiently expressed after stimulation, it may increase T-cell proliferation in an activation-dependent and superantigen-like but apparently Vbeta-independent way.

Determination of albuterol in plasma after aerosol inhalation by gas chromatography-mass spectrometry with selected-ion monitoring

Albuterol is a beta2-adrenergic agonist commonly used as a bronchodilator for the treatment of patients with asthma. We have developed an assay to determine plasma levels as low as 50 pg/ml of albuterol by gas chromatography-mass spectrometry (GC-MS). This assay utilizes isotopically labeled albuterol ([13C]albuterol) as an internal standard. In this assay albuterol and the internal standard are recovered from 1 ml of plasma using solid-phase extraction. The samples are then derivatized to trimethylsilyl ethers using N,O-bis(trimethylsilyl)trifluoro-acetamide with 1% trimethylchlorosilane. The samples are then analyzed by GC-MS with selected-ion monitoring (SIM) for the ions m/z 369.15 and 370.15. The method has been validated for a concentration range of 50-10000 pg/ml in plasma.

[Simplified storage procedure of cryopreserved human parathyroid tissue]

Parathyroid tissue that is stored for replantation purposes is usually kept in a special tank containing fluid nitrogen at -196 degrees C. Our studies demonstrate that storage is also possible in a deep-freezer at -70 degrees C without any loss of quality. Most hospitals own such freezers for storing bone marrow cells at the same temperature. Parathyroid tissue of 11 patients who were operated on because of primary hyperparathyroidism was stored in this way. After six months the tissue showed 75.7% morphologically intact cells. The control group's tissue was stored in liquid nitrogen according to the common method; after the same period of time it showed 76% histologically normal cells.

Nucleotide sequence of a cDNA coding for the NADPH-protochlorophyllide oxidoreductase (PCR) of barley (Hordeum vulgare L.) and its expression in Escherichia coli

The primary structure of the NADPH-protochlorophyllide oxidoreductase of barley has been deduced from the nucleotide sequence of a cloned full-length cDNA. This cDNA hybridizes to a 1.7 kb RNA whose steady-state level in dark-grown seedlings is drastically reduced upon illumination. The predicted amino acid sequence (388 residues in length) includes a transit peptide of 74 amino acids whose end point has been delimited by sequencing the N-terminus of the mature protein. Expression of the cDNA in Escherichia coli leads to the synthesis of an enzymatically active precursor of the NADPH-protochlorophyllide oxidoreductase. Activity of this protein in bacterial lysates is completely dependent on the presence of NADPH and protochlorophyllide and requires light.

Leaf-specific thionins of barley-a novel class of cell wall proteins toxic to plant-pathogenic fungi and possibly involved in the defence mechanism of plants

A novel class of highly abundant polypeptides with antifungal activity has been detected in cell walls of barley leaves. Similar polypeptides known as thionins occur not only in monocotyledonous but also in various dictoyledonous plants. The leaf-specific thionins of barley are encoded by a complex multigene family, which consists of at least 50-100 members per haploid genome. All of these genes are confined to chromosome 6. The toxicity of these thionins for plant pathogenic fungi and the fact that their synthesis can also be triggered by pathogens strongly suggest that thionins are a naturally occurring, inducible plant protein possibly involved in the mechanism of plant defence against microbial infections.

[Urticaria vasculitis]

Urticarial vasculitis is a syndrome characterized by a chronic intermittent urticaria and the histological features of necrotizing vasculitis. The skin lesions are often accompanied by arthritis or arthralgia and other systemic diseases. Depressed serum complement can be found in half of the patients.

Characterization of a beta-adrenergic receptor in porcine trachealis muscle

To establish a model of airway smooth muscle function we studied binding of [3H]dihydroalprenolol [( 3H]DHA), a beta-adrenergic antagonist, to membrane preparations of porcine trachealis muscle and investigated the response of adenylate cyclase to l-isoproterenol in tissue and plasma membranes. [3H]DHA binding was of high affinity (Kd = 1.0 +/- 0.1 nM), was saturable (Bmax = 87.6 +/- 13.2 fmol/mg protein), and was 90% beta 2 and 10% beta 1. Adenylate cyclase activity in the membrane preparation was (in pmol.10 min-1.mg protein-1 +/- SE): basal 420 +/- 74, guanosine 5'-triphosphate (GTP) (10 micron) 600 +/- 45, GTP (10 microM) + l-isoproterenol (100 microM) 660 +/- 63, NaF (10 mM) 1,500 +/- 134, and forskolin (100 microM) 3,000 +/- 410. Guanosine 5'-diphosphate (GDP) and GTP were active cofactors; l-isoproterenol appeared to function as an effector exchanging GTP for GDP on the guanine nucleotide regulatory protein. There was close agreement of the effective dose (ED50) of the l-isoproterenol-induced relaxation (0.95 +/- 0.45 microM) and the inhibitory constant of l-isoproterenol binding (0.39 +/- 0.10 microM). l-Isoproterenol (100 microM) induced a 100% increase in adenosine 3',5'-cyclic monophosphate (cAMP) levels in tissue strips over basal activity. Investigation of the difference in adenylate cyclase activity between tissue and plasma membranes revealed that l-isoproterenol responsive adenylate cyclase was diminished after initial homogenization. Electron microscopy demonstrated disruption of all cells at this early stage of preparation. The decrease in l-isoproterenol responsive adenylate cyclase following cell rupture is different from other tissues and suggests a difference in the actions of beta-agonist in smooth muscle compared with other tissues.

Hereditary ataxia and the sixth chromosome

Possible linkage of the gene or genes for dominant hereditary ataxia and three genetic markers on the short arm of the sixth chromosome (HLA, properdin factor B [Bf], and glyoxalase I) was investigated in five families. Logarithmic odds (lod scores) were calculated for the linkages and found to be either inconclusive or in favor of nonlinkage. Caution is advised in the summing of lod scores for separate families because of the wide spectrum of clinical and anatomical manifestations of dominant hereditary ataxia. Three families with recessive hereditary ataxia were also studied. Identical haplotypes occurred in affected and unaffected siblings. It did not appear likely that the recessive genes of the parents were transmitted in linkage with the markers on the short arm of the sixth chromosome.

[The battered child (Medical and legal questions for the gynaecologist) (author's transl)]

The syndrome of the battered child is described. The legal problems arising from the conflicts between the two basic rights of medical confidentiality and protection of the child are discussed. The relevant paragraphs of the penal code, the civil code and the West German constitution are discussed. A practical solution for the physician in this conflict situation is information of the finding of a trauma of unknown origin to the child protection agency.

Aerodynamic size distribution of cromolyn sodium at ambient and airway humidity

The aerodynamic size distribution of cromolyn sodium was determined at ambient and high (98%) humidity using the single particle aerodynamic relaxation time analyzer. This instrument measures the aerodynamic size single, suspended solid particles and liquid droplets in the respirable size range. The measurement accommodates all properties such as density, shape and surface characteristics that affect aerodynamic behavior. Particle morphology under ambient humidity conditions was studied using scanning electron microscopy. Count median aerodynamic diameter increased from 1.40 to 1.52 micron (p < 0.05), and the mass median aerodynamic diameter increased from 2.31 to 3.02 micron (p < 0.005) when measured at ambient and high humidities. The total mass of 0.99 mg of active ingredient aerosolized at ambient humidity in the size range compatible with pulmonary deposition was approximately 5% of the total mass of active ingredient packaged in the capsule. The low mass of particle aerosolized in the size range appropriate for pulmonary deposition may explain the low estimated deposition of cromolyn reported by other investigators.

Aerodynamic size distribution of metered-dose bronchodilator aerosols

The aerodynamic size distributions of 9 commonly used bronchodilator aerosols were determined by using a new instrument, the single-particle, aerodynamic relaxation time analyzer, which can measure the aerodynamic size of single particles and droplets in real time independent of density, shape, and other physical characteristics. The following commercial preparations were studied: Duo-Medihaler, Medihaler-Epi, Medihaler-Epi Medihaler-Iso, Norisodrine Aerotrol, Alupent, Metaprel, Isuprel Mistometer, Bronkometer, and Asthma-Meter. Count median diameters ranged from 0.62 to 0.82 micrometer, and mass median aerodynamic diameters ranged from 2.8 to 4.3 micrometer. The heterodisperse nature of the aerosols was demonstrated by the relatively large geometric standard deviations, which ranged from 1.5 to 2.1. None of these aerosols had a log-normal distribution; rather, the distribution curves were multimodal.

Modern treatment of bronchial asthma

Various biochemical mediators and autonomic events lead to symptom-causing pathological changes in asthma attacks, that is, mucosal edema, mucous gland hypersecretion, and bronchial smooth muscle contraction. The discovery of alpha and beta adrenergic receptors, and the observation that cyclic AMP is the intracellular effector in cells stimulated by various hormones, led to a better understanding of the mechanism of action of medications of asthma. Emergence evaluation, in addition to history, physical findings, and physiological status, should include prior asthma history, physical findings, and physiological status, should include prior asthma history. Initial emergency therapy in patients with a history suggesting responsiveness to simple measures includes subcutaneous epinephrine, 0.2 to 0.5 mg, or terbutaline sulfate, 0.25 mg. Also, the patient may benefit from inhalation of an aerosolized bronchodilator. Patients who do not respond to initial treatment in three to four hours or who deteriorate, should be hospitalized. Hospitalized asthma patients should be constantly observed and monitored. The emergency treatment should be continued vigorously. Corticosteroid therapy should be started upon admission. The response rate to therapy in the hospitalized asthmatic is highly variable. Outpatient management involves patient education in the nature of asthma and in the fact that multiple drugs and frequent changes in therapy may be required to bring the symptoms under control.

Analysis of the HLA-ABC linkage disequilibrium: decreasing strength of gametic association with increasing map distance

1242 HLA-ABC haplotypes of the North German population (Hambrug) as deduced by family analyses are described. They are in perfect agreement with recently published data by Mayr (1977) from Austria (Vienna) in all parameters tested: frequency of the single HLA-alleles, haplotype distribution and linkage disequilibrium values. Gametic association studies revealed that 69.4% of the B and C genes (map distance 0.2cM) 36.9% of the A and C genes (0.6 cM), but only 23.2% of the A and B genes (0.8 cM) were significantly more often combined than expected due to their frequencies. From these findings it seems likely that the linkage disequilibrium within the MHC is rather due to a short evolutionary period than to selective forces. Some observations as to the most common European haplotype A1,B8 are discussed.

Foreign body removal with the flexible fiberoptic bronchoscope

Intrabronchial foreign bodies are occasionally encountered in adults but most available information in humans consists only of reports evaluating one or two cases. We surveyed our experience and found seven patients with intrabronchial foreign bodies who had been examined with the flexible fiberoptic bronchoscope, six of whom were managed successfully. Nine cases have been identified in the literature. Although there were no major complications in either our cases or those in the literature, several problems were identified which under other circumstances could have caused significant complications. We assessed all of these cases for situations which presented potential risk to the patient. These risks were grouped into the following problem categories: 1. selection of appropriate bronchoscope, 2. availability of appropriate instruments, 3. control of the foreign body, and 4. unexpected foreign bodies. Endoscopists planning to use the FFB in foreign body removal should be aware of the problems and hazards which may ensue if improperly managed, and should attempt to gain experience either in the animal laboratory or in models prior to approaching patients with foreign bodies with the flexible fiberoptic bronchoscope.

Haplotype analysis of the linkage group HLA-A:HAL-B:Bf and its bearing on the interpretation of the linkage disequilibrium

The analysis of 650 HLA-A:HAL-B:Bf three-factor haplotypes revealed significant associations only between alleles of the very closely linked genes HLA-A and HLA-B, and Bf, respectively. Most striking is the highly significnat association of the rare Bf variant F1 with HLA-B18 and of S1 with HLA-B13, HLA-B14, and HLA-Bw21. Only random allele distributions were observed when considering the somewhat more distant genes HLA-A and Bf or the higher order interaction at all three genes. From these findings it seems likely that the linkage disequilibrium within the MHC is not due to selective forces, but rather due to a short evolutionary period.

No indication of postnatal selection at the HL-A loci

When the HL--A allele frequency and the distribution of 2, 3 and 4 different antigens, respectively, in children and old people were compared no differences could be observed between the two groups. The data thus disprove a simple model by which HL--A heterozygosity should enhance surveillance.

Linkage studies between HL-A and GPT polymorphisms and other genetic markers

The phenotypes of 56 families with 126 children from the Hamburg area as well as gene frequencies and segregation of the genetic markers GPT, AP, ADA, AK, PGM1, PGM3, 6-PGD, CHE, C3, Gc, Tf, Hp and Cp were studied. In regard to linkage, the informative families were correlated to the results of HL-A and GPT typing. The linkage was tested according to the sequential test by MORTON (1955). See article. For other gene loci, linkage to the HL-A or GPT system could not be proved. But the positive lod scores of HL-A/GPT, HL-A/AP and GPT/6-PGD may give indication for linkage.

Establishing an optical flatness standard

Methods proposed by the authors to establish a flatness standard without using a liquid mirror are proved in practice and extended. The extension is performed by a development of methods for the determination and compensation of random and systematic measuring errors by means of condition equations which must be satisfied by the measured sums of deviations from absolute planeness. Linear errors of these sums of deviations which can lead to ambiguities and errors of planeness deviations can be discovered and completely eliminated. Also nonlinear errors, for example, as a result of temperature differences or of mechanical stress, can be recognized without repeating the interference photography procedure. The deviations from absolute planeness of three fused silica plates were determined along seven diameters (angular distance 2pi/14) with an accuracy of lambda/500 (mean square error). This was performed by evaluating two sets of four different interference photographs, each with contour plane distances of lambda/50 (from fringe to fringe).