Towards synthetic viruses.

Gene delivery is too complex to be performed with a single carrier molecule. Synthetic multicomponent vectors are being designed that mimic key properties of viruses. Some solutions, such as diverting cell-anchoring molecules or the endogenous nuclear import machinery from their normal function, are directly copied from bacteria and viruses. Some other solutions are original ones: monomolecular genome condensation via detergent dimerization or endosome disruption by the proton sponge effect are not exploited by natural cell invaders. All these components, however, still have to be assembled into a unique supramolecular system, an 'artificial virus'.

Assembly of retrovirus capsid-nucleocapsid proteins in the presence of membranes or RNA.

Retrovirus Gag precursor (PrGag) proteins direct the assembly of roughly spherical immature virus particles, while after proteolytic processing events, the Gag capsid (CA) and nucleocapsid (NC) domains condense on viral RNAs to form mature retrovirus core structures. To investigate the process of retroviral morphogenesis, we examined the properties of histidine-tagged (His-tagged) Moloney murine leukemia (M-MuLV) capsid plus nucleocapsid (CANC) (His-MoCANC) proteins in vitro. The His-MoCANC proteins bound RNA, possessed nucleic acid-annealing activities, and assembled into strand, circle (or sphere), and tube forms in the presence of RNA. Image analysis of electron micrographs revealed that tubes were formed by cage-like lattices of CANC proteins surrounding at least two different types of protein-free cage holes. By virtue of a His tag association with nickel-chelating lipids, His-MoCANC proteins also assembled into planar sheets on lipid monolayers, mimicking the membrane-associated immature PrGag protein forms. Membrane-bound His-MoCANC proteins organized into two-dimensional (2D) cage-like lattices that were closely related to the tube forms, and in the presence of both nickel-chelating lipids and RNAs, 2D lattice forms appeared similar to lattices assembled in the absence of RNA. Our observations are consistent with a M-MuLV morphogenesis model in which proteolytic processing of membrane-bound Gag proteins permits CA and NC domains to rearrange from an immature spherical structure to a condensed mature form while maintaining local protein-protein contacts.

Chemometrics approach to the determination of polymorphism of a drug compound by infrared spectroscopy.

A chemometrics approach, multivariate calibration in particular, was used to determine the polymorphism of a drug compound based on Fourier transform infrared (FTIR) spectroscopy. The partial least-squares projection to latent structure makes use of all of the data, and the latent variables created by the method make use of hidden or partially separated peaks for quantitation. This paper illustrates the usefulness of the partial least-squares multivariate calibration method as an efficient tool to determine the polymorphism of a drug. Also, the analysis suggests the use of information from the modeling as diagnostic tools to gain more insight from the data. In particular, the diagnostic tools allow an analyst to assess design characteristics and any shortcomings of a calibration experiment for the polymorphism of a drug compound.

Atomic force microscopy and electron microscopy analysis of retrovirus Gag proteins assembled in vitro on lipid bilayers.

We have used an in vitro system that mimics the assembly of immature Moloney murine leukemia virus (M-MuLV) particles to examine how viral structural (Gag) proteins oligomerize at membrane interfaces. Ordered arrays of histidine-tagged Moloney capsid protein (his-MoCA) were obtained on membrane bilayers composed of phosphatidylcholine (PC) and the nickel-chelating lipid 1, 2-di-O-hexadecyl-sn-glycero-3-(1'-2"-R-hydroxy-3'N-(5-amino-1-carboxy pentyl)iminodiacetic acid)propyl ether (DHGN). The membrane-bound arrays were analyzed by electron microscopy (EM) and atomic force microscopy (AFM). Two-dimensional projection images obtained by EM showed that bilayer-bound his-MoCA proteins formed cages surrounding different types of protein-free cage holes with similar cage holes spaced at 81.5-A distances and distances between dissimilar cage holes of 45.5 A. AFM images, showing topological features viewed near the membrane-proximal domain of the his-MoCA protein, revealed a cage network of only symmetrical hexamers spaced at 79-A distances. These results are consistent with a model in which dimers constitute structural building blocks and where membrane-proximal and distal his-MoCA regions interact with different partners in membrane-bound arrays.

Rigidone, a sesquiterpene o-quinone from the gorgonian Pseudopterogorgia rigida.

As part of a search for novel biologically active compounds in the Macrophage Scavenger Receptor (MSR) assay, the EtOAc extract of a gorgonian coral, Pseudopterogorgia rigida, was shown to be active. Bioassay-guided fractionation of the extract yielded curcuphenol, curcuhydroquinone, curcuquinone, and a novel o-quinone, rigidone (1). The structure and stereochemistry of 1 was determined by interpretation of spectral data and chemical transformation.

Cleavage of tRNA with imidazole and spermine imidazole constructs: a new approach for probing RNA structure.

Hydrolysis of RNA in imidazole buffer and by spermine-imidazole conjugates has been investigated. The RNA models were yeast tRNA(Asp) and a transcript derived from the 3'-terminal sequence of tobacco mosaic virus RNA representing a minihelix capable of being enzymatically aminoacylated with histidine. Imidazole buffer and spermine-imidazole conjugates in the presence of free imidazole cleave phosphodiester bonds in the folded RNAs in a specific fashion. Imidazole buffer induces cleavages preferentially in single-stranded regions because nucleotides in these regions have more conformational freedom and can assume more easily the geometry needed for formation of the hydrolysis intermediate state. Spermine-imidazole constructs supplemented with free imidazole cleave tRNA(Asp) within single-stranded regions after pyrimidine residues with a marked preference for pyrimidine-A sequences. Hydrolysis patterns suggest a cleavage mechanism involving an attack by the imidazole residue of the electrostatically bound spermine-imidazole and by free imidazole at the most accessible single-stranded regions of the RNA. Cleavages in a viral RNA fragment recapitulating a tRNA-like domain were found in agreement with the model of this molecule that accounts for its functional properties, thus illustrating the potential of the imidazole-derived reagents as structural probes for solution mapping of RNAs. The cleavage reactions are simple to perform, provide information reflecting the state of the ribose-phosphate backbone of RNA and can be used for mapping single- and double-stranded regions in RNAs.

Nonenzymatic plasmid ligation mediated by minor groove-binding molecules.

DNA ligation is the weak link in the chain of gene cloning. We have developed a straightforward nonenzymatic alternative to this reaction that employs easily available commercial reagents. The method uses the affinity of distamycin for the minor groove to join DNA ends together. Phosphodiester bonds are formed after cyanoimidazole-promoted phosphate activation in the presence of manganese(II) cations. When transfected into eukaryotic cells, the chemically ligated plasmid is transcribed even more efficiently than after enzymatic ligation. At present this technique compares favorably with T4 ligation for AT-rich cohesive termini, but in principle it could be extended to any restriction site.

Application of Fourier transform infrared spectroscopy to studies of aqueous protein solutions.

Modern protein Fourier transform infrared (FT-IR) spectroscopy has proven to be a versatile and sensitive technique, applicable to many aspects of protein characterization. The major practical drawback for the FT-IR spectroscopy of proteins is the large absorbance band of water, which overlaps the amide I resonances. D2O is often substituted for H2O in infrared experiments. Removal of water from protein samples can be complicated and tedious and potentially lead to denaturation, aggregation, or sample loss. Solvent removal by dialysis is difficult for suspensions and sols. A new method called the D2O dilution technique (Ddt) is described which simplifies the sample preparation step and improves the solvent subtraction. The effect of the D2O concentration on the IR spectrum of aqueous solutions of several model proteins was studied. Dilution of aqueous samples with D2O yields good quality spectra. The Ddt has been evaluated for quantitative analysis using standard proteins and its applicability to solutions and suspensions of a genetically engineered malaria antigen is demonstrated. Use of resolution-enhancement techniques with spectra in mixed solvents has also been investigated.

Specific effect of corticoids on acetylcholine receptor expression in rat skeletal muscle cell cultures.

The potential effect of different classes of steroids on the expression of acetylcholine receptors (AChR) was studied in different primary cultures of newborn-rat skeletal muscle cells. Comparison among three techniques for preparing newborn skeletal muscle cells showed that these systems were equivalent to study AChR expression. Only corticoids stimulated myogenesis as a twofold increase in AChR expression indicated. Among the corticoids, the glucocorticoids were the more potent, whereas the mineralocorticoid aldosterone had less marked effect. The sex hormones progesterone and testosterone partially blocked these effects, without inducing any significant effect when given alone. The steroids tested differed in efficacy in correlation with their different chemical structures. Among the glucocorticoids a clear structure-activity relationship could be established. These results emphasize the specificity of corticoid action on muscle cells and suggest an explanation for the effects induced by glucocorticoids used in treating human muscular or neuromuscular diseases.

[Primary sclerosing cholangitis]. / Die primär-sklerosierende Cholangitis.

In a 40-year-old patient unexplained recurrent attacks of epigastric colic with transient cholestatic icterus occurred over a 9-year period. When the patient was again hospitalised because of progressive pain-free icterus associated with mild pruritus (alkaline phosphatase 900 U/l, direct bilirubin 305 mumol/l, GOT 187 U/l, GPT 103 U/l) sonography revealed liver enlargement to 17 cm, extended intrahepatic bile ducts and an echodense area of about 1 cm size in the region of the bifurcation of the common hepatic duct. Fine-needle puncture did not yield clear cytological findings. Endoscopic retrograde cholangiopancreatography pointed to sclerosing cholangitis. This diagnosis was confirmed by liver punch biopsy. Since the patient did not agree to a liver transplantation, he was treated with 450 mg ursodeoxycholic acid twice daily, resulting in marked reduction of the liver parameters until severe cholangiosepsis and acute renal failure occurred about 4 months later. The septic condition and its complications could not be managed despite thorough intensive-care measures so that a liver transplant had to be performed after all. Histology of the explantate revealed a cholangiocarcinoma in the region of the bifurcation of the common hepatic duct. At first the patient's condition improved markedly but one and half months later the transplant was rejected and the patient died.

[Eosinophilic fasciitis (Shulman's syndrome)]. / Eosinophile Fasziitis (Shulman-Syndrom).

A 36-year-old man had noted a firm and painful swelling of the upper and lower limb, increasing over the previous few weeks. He had no fever, but the erythrocyte sedimentation rate was slightly increased (20 mm in the first hour). In addition there was a mild normochromic, normocytic anaemia (13 g/dl) and thrombocytosis (517,000/microliters). Gamma-globulin fraction was raised to 26%. The blood eosinophilia of 44% and the histological findings in a wedge biopsy of the lower leg (oedematous widened connective tissue septa, inflammatory infiltrate with eosinophilic granulocytes) established the diagnosis of eosinophilic fasciitis (Shulman syndrome). During oral treatment with prednisone (100 mg/d) the clinical symptoms regressed and the eosinophilia in peripheral blood disappeared. In the course of the subsequent seven months the prednisone dose was reduced gradually to 10 mg daily. But, because the symptoms did not entirely disappear the prednisone dose had to be increased temporarily for four times until there was a further, stepwise, reduction of the symptoms. But mild induration of the lower leg persisted. Maintenance treatment with prednisone, 10 mg daily, has been continued in order to avoid recurrence.

[Paroxysmal non-hereditary angioedema]. / Paroxysmales nicht-hereditäres Angioödem.

Recurrent hypovolaemic shock had been occurring over the last five and four years, respectively, in a 53-year-old woman and a 46-year-old man who had previously been healthy. The attacks were characterized by a tension feeling and sometimes oedema in the limbs, as well as increased thirst. Within a few hours sweating, tachycardia, orthostatic complaints and shock would occur. The woman's systolic blood pressure would fall to 70 mm Hg and the pulse rate rise to 150/min. The man's blood pressure was not measurable by sphygmomanometer during his first attack. Haematocrit rose to 61 and 71.5%, haemoglobin concentration to 20.7 and 21.3 g/dl, respectively. On administration of plasma expanders all abnormal clinical and biochemical changes quickly disappeared, only to recur within weeks or months. The cause of the condition is an increased permeability of the tissue capillaries, while renal, pulmonary and cerebral vessels apparently are unaffected. During ketotifen and tebonin (gingko biloba extract) administration to the man, he required no further hospitalization for nine months, after which he had three severe attacks. The woman had a severe attack of hypovolaemic shock one month on this treatment. The prognosis of capillary leak syndrome is bad.

High cell density fermentation of recombinant Escherichia coli expressing human interferon alpha 1.

A defined medium was developed which, by means of a specific fed-batch mode, allows growth of the recombinant Escherichia coli strain TG1 (pBB210) up to a cell density of 60 g dry weight/l. Apart from glucose and aqueous ammonia fed as carbon and nitrogen sources, it was necessary to supply other nutrients or O2-enriched air. Aqueous ammonia also served for pH control. The pO2 level was kept at 20% saturation via closed-loop controls operating the two output variables of stirrer speed and glucose feeding rate. This fed-batch method prevented significant accumulation of acetate and other metabolic by-products. The recombinant E. coli expressed interferon alpha 1 more efficiently at a lower specific growth rate (muPr approximately 0.15 h-1) than at the maximum specific growth rate (mu max = 0.45 h-1). Therefore, fermentation in the batch phase at mu max was only allowed to continue up to a medium cell density. In the succeeding fed-batch phase, the specific growth rate was reduced to muPr by increasing the stirrer speed according to an empirically developed time scale.

5,5-Dimethylthiazolidine-4-carboxylic acid (DTC) as a proline analog with restricted conformation.

Spectroscopic evidence is presented for the lack of intramolecular hydrogen bonding in a simple peptide derivative of 5,5-dimethylthiazolidine-4-carboxylic acid (Dtc). The infrared spectrum of Boc-Pro-Ile-OMe 1 in nonpolar solvents displays two N-H stretching bands at 3419 and 3330 cm-1 in CCl4 and one at 3417 and 3328 cm-1 in CHCl3. The low frequency band at 3328-3330 cm-1 may be assigned to conformations with an intramolecular hydrogen bond between the Ile N-H and Boc C = O. The band at 3417-3419 cm-1 is the normal Ile N-H stretch. In the polar solvent CH3CN only one NH stretching band at 3365 cm-1 is observed. The IR spectrum of Boc-Dtc-Ile-OMe 2, on the other hand, displays one N-H stretching band at 3423 cm-1 in CCl4 and one at 3418 cm-1 in CHCl3. The IR spectrum of 2 does not display the N-H stretching band that would arise from intramolecular hydrogen bonding between the Boc C = O and Ile N-H. The lack of intramolecular hydrogen bonding for Boc-Dtc-Ile-OMe 2 was evident also in the NMR spectra in nonpolar solvents. The 1H-NMR spectrum of the Pro dipeptide 1 in 50% CDCl3/C6D6 at 20 degrees displayed two Ile-NH signals at 6.58 and 7.74 ppm. The latter signal corresponds to the intramolecularly hydrogen bonded Ile-NH in the trans-Boc isomer of 1 (60% of the total population), while the former signal corresponds to the nonhydrogen bonded Ile-NH in the cis-Boc isomer.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intestinal drug smuggling--a new diagnostic and therapeutic problem]. / Intestinaler Rauschgiftschmuggel--ein neues diagnostisches und therapeutisches Problem.

Since spring 1985 81 persons were examined because of suspected intestinal drug-smuggling (body-packing). 46 patients (57%) had drug-packages in the gastro-intestinal tract, in 35 persons (43%) the suspicion was not confirmed. 26 patients had swallowed the drugs (mostly cocaine) whereas in 20 cases drugs were found in the rectum (mostly heroine). Most important for diagnosis was abdominal x-ray whereas in our hands abdominal sonography was unreliable. When body-packing is diagnosed, observation and mild laxative in conjunction with sufficient beverages are recommended. Serious complications in our series comprised one patient with mechanical ileus and another with heroine-poisoning after rupture of a package.

[Idiopathic cold agglutinin disease. Clinical aspects, therapy and course in 6 patients]. / Die idiopathische Kälteagglutininkrankheit. Klinik, Therapie und Verlauf bei 6 Patienten.

Clinical features, diagnostic procedure, therapy, course of the disease and prognosis in 6 patients with severe idiopathic chronic cold agglutinin disease are described. In 5 patients the main complaint was cold mediated acrocyanosis. The cold agglutinin in all patients was of anti-I type and belonged to IgM immunoglobulin. Keeping warm provided symptomatic relief and the hemolysis decreased to a milder form. Treatment with glucocorticoids alone failed in two patients but succeeded in combination with chlorambucil or cyclophosphamid. One patient developed a lymphoproliferative disorder 11 years after diagnosis of idiopathic chronic cold agglutinin disease.

[Principles of modern antibiotic therapy in general practice and the clinic]. / Grundsätze moderner Antibiotikatherapie in Praxis und Klinik.

It is reported on the principles of modern therapy with antibiotics and here above all is referred to the differences in the antibiotic treatment in practice and clinic. Issuing from the infections usually occurring in practice with the spectre of causative agents known in many cases the therapeutic possibilities are discussed also taking into consideration economic points of view. In contrast to this in infections in the clinic, so-called nosocomial diseases, changing situations are present, which need a therapy on the basis of the antibiogramme. In these cases partly also combination therapies for the enlargement of the spectre of action and for the increase of the antibacterial activity are used.