Cytotoxic T cells and neutralizing antibodies induced in rhesus monkeys by virus-like particle HIV vaccines in the absence of protection from SHIV infection

HIV Pr55gag has in the absence of other viral components the capacity to self assemble in budding noninfectious virus-like particles (VLP). The immunological spectrum of the HIV-1IIIB gag-derived VLP was expanded either by stable anchoring of chimeric modified gp 120 on the surface of the VLP (type 1) or by replacing sequences of the Pr55gag precursor by the V3 loop and a linear portion of the CD4 binding domain (type 2). This noninfectious antigen delivery system was evaluated for immunogenicity and efficacy in rhesus macaques without adjuvants. Intramuscular immunization with both types of VLP induced high titers of gag-specific antibodies ranging from 1/8000 to 1/510,000 for type 1 VLP and from 1/4000 to 1/16,000 for type 2 VLP. Only animals immunized with type 1 VLP developed substantial endpoint titers of env-specific antibodies (1/2000-1/32,000) with a neutralizing capacity at serum dilutions of 1/32-1/128. Gag- and env-specific cytotoxic T lymphocyte (CTL) activity was induced by both types of VLP at similar levels. Four weeks after the last immunization animals were challenged intravenously with 20 MID50 of the cell free homologous envelope simian/HIV-1IIIB chimeric challenge stock Despite HIV-1-specific neutralizing and CTL responses, all vaccinated animals became infected.

32-Ascomycinyloxyacetic acid derived immunosuppressants. Independence of immunophilin binding and immunosuppressive potency

The potent immunosuppressant ascomycin (1b) was selectively alkylated at the C-32 carbinol, thus providing esters and amides of 32-ascomycinyloxyacetic acid (4, AOAA). These compounds present structural variation at the FKBP/calcineurin interface. While the native carboxylic acid 4 shows no activity in vitro, esters and simple amides of 4 exhibit potent immunosuppression in the human MLR assay. Moreover, amides show inhibitory activity in the rat popliteal lymph node hyperplasia assay. Surprisingly, FKBP binding was weakened by several orders of magnitude when secondary hydrophobic aryl amides of 4 were tested, while maintaining potent immunosuppressive efficacy in vitro.

Altered serum amino acid profiles in head and neck cancer

Patients who develop squamous cell carcinoma of the head and neck (SCCHN) are often malnourished because of poor dietary habits, excessive alcohol consumption, local tumor effects, tumor-induced cachexia, and the effects of various therapies. The composition of the diet may be a risk factor for the development of head and neck cancer as well as tumor progression. This study compares the amino acid profiles in the banked serum of patients with and without SCCHN. In comparison to the control group, patients with SCCHN had significantly decreased preoperative serum levels of alanine (p = 0.006), asparagine (p = 0.002), aspartic acid (p = 0.0001), glycine (p = 0.0002), histidine (p = 0.002), 3-methylhistidine (p = 0.001), ornithine (p = 0.001), phenylalanine (p = 0.002), serine (p = 0.002), taurine (p < 0.0001), and threonine (p = 0.001). Levels of cystine were significantly elevated in the group of cancer patients (p < 0.0001). No significant differences were noted on the basis of T stage, N stage, or nutritional status. Serum levels increased postoperatively for the majority of the amino acids tested. Postoperative histidine levels were associated with tumor recurrence (p = 0.04). Serum amino acid levels may prove to be useful markers of disease status and provide prognostic information.

A highly sensitive gas chromatographic determination of levamisole in milk

An efficient extraction and sensitive gas chromatographic method is described for the determination of the anthelminthic drug levamisole in milk. Levamisole was extracted from alkaline milk with ethyl acetate. Clean-up of the extract was by a series of liquid-liquid extraction steps. Levamisole residues in the extract were determined by gas chromatography with a nitrogen-phosphorus detector. This method was satisfactory for determining levamisole residues in milk as low as 0.5 ng/g. Mean recoveries of 0.5-10.0 ng/g fortified milk samples ranged from 84.5 to 95.2%. Five replicate analyses performed on a milk containing incurred levamisole residues yielded a mean of 3.34 ng/g levamisole with a CV of 3.0%.

Thylakoid membranes contain a high-conductance channel

Ion channels in the thylakoid membrane were investigated by direct patch clamping on swollen thylakoids. A preparation method has been developed in order to release osmotically swollen intact thylakoids from pea protoplasts derived from cotyledons of young Pisum sativum plants. The swollen thylakoids with typical diameters between 10 microm and 20 microm formed reproducibly high-resistance seals with patch pipettes. We observed a potassium channel with a main conductant state of lambda approximately 40 pS and a conductance of lambda approximately 90 pS (in asymmetric 20/100 mM KCl) for the fully open channel. Surprisingly, the thylakoid membranes also contained a high-conductance channel with a main conductant state of lambda approximately 620 pS (in asymmetric 20/100 mM KCl), revealing also higher and lower conductant states. With a different experimental approach we showed that thylakoids are able to accumulate transiently the membrane impermeant fluorescent dye Lucifer Yellow which likewise suggests the presence of a pore-like channel with a diameter large enough to allow permeation of Lucifer Yellow.

[Quality-related education in general medicine]

On the basis of depth interviewing we obtained detailed qualitative data about opinions, experiences and needs of general practitioners (GP) concerning continuing medical education. Two main topics were health promotion and psychosocial aspects of the GP's daily work. Following a broad discussion of the results--comprehensively considering international research--we developed a modern conception for a worth-while and independent continuing medical education leading to a more individualised learning and teaching.

Plasma concentrations of leptin in a bulimic patient

Recently, the obese gene in the ob/ob mouse was cloned, along with its human homologue. The gene product leptin is important in the regulation of body weight. Excessive food intake during a binge might affect leptin synthesis. Alternatively, fluctuations in leptin synthesis might induce binge eating. Therefore, plasma leptin levels of a patient with bulimia nervosa were determined over a period of 48 hr in a natural setting. Amount, type, time of food intake, and binging and purging episodes were concomitantly assessed. Although binging and purging episodes were quite frequent, leptin levels remained stable and were neither related to food intake nor to binge episodes.

Effects of the Escherichia coli DNA-binding protein H-NS on rRNA synthesis in vivo

The Escherichia coli DNA-binding protein H-NS is known to interact specifically with the upstream region of ribosomal RNA transcription units, where it causes transcriptional repression in vitro. Here, we present results demonstrating the effect of H-NS on rRNA transcription in vivo. rRNA synthesis rates were compared in cells that differ in the expression of functional H-NS or FIS molecules. We could show that in the absence of H-NS derepression of rRNA synthesis occurs at low growth rates. During the cell cycle H-NS is responsible for the rapid shut-off of rRNA synthesis at the end of the exponential phase. As it is known for FIS-dependent activation, the inhibitory function of H-NS is specific for P1, the first of the tandem rRNA promoters. The effect of H-NS on rRNA synthesis was further assessed under stress conditions. While under osmotic upshift the reduction in rRNA synthesis is clearly H-NS-dependent, no such influence could be detected at cold shock. Determination of the cellular ppGpp concentrations revealed that H-NS does not mediate its function via alterations in the synthesis of the global effector ppGpp.

Intracellular UDP-N-acetylhexosamine pool affects N-glycan complexity: a mechanism of ammonium action on protein glycosylation

Understanding the mechanisms by which ammonium ions affect glycosylation may suggest strategies for producing glycoproteins with homogeneous biological activity in the presence of undesirable byproducts of cellular energy metabolism. We have previously shown that ammonium ions cause an increase in the intracellular UDP-N-acetylhexosamine (UDPGNAc) pool, which may be responsible for the ammonium-induced increase in complexity and decrease in sialylation state of the N-linked oligosaccharide. To investigate this novel hypothesis, we induced an artificial increase in UDPGNAc pool by treating recombinant BHK cells expressing an IL-2 variant that features an artificial site for N-glycosylation, with glucosamine (1:2 molar ratio to glucose) and uridine (2 mmol L-1) in the absence of ammonium ions or glutamine. The product fractions collected during this treatment showed increased antennarity compared to product collected under control conditions. When this pool was returned to normal levels, the glycosylation pattern regained its original (control) features. However, the sialylation state remained unaffected, suggesting that the decreased sialylation observed under ammonium treatment is due to a different mechanism of action, possibly involving changes in intracellular pH. By pretreating the cells with 0.5 mmol L-1 adenosine, and exposing them continuously to NH4Cl and adenosine we were able to prevent the ammonium-induced increase in UDPGNAc. Product fractions collected during this treatment showed unchanged antennarity but decreased sialylation of the N-linked oligosaccharide, thus conclusively demonstrating that ammonium ions act on protein glycosylation by at least two independent mechanisms, one of which involves an increase in the UDPGNAc pool.

Nonlinear optics in relativistic plasmas

We review our recent work on the various nonlinear optical processes that occur as an intense laser propagates through a relativistic plasma. These include the experimental observations of electron acceleration driven by laser-wakefield generation, relativistic self-focusing, waveguide formation and laser self-channeling.

Ammonium ion and glucosamine dependent increases of oligosaccharide complexity in recombinant glycoproteins secreted from cultivated BHK-21 cells

The effect of different ammonium concentrations and glucosamine on baby hamster kidney (BHK)-21 cell cultures grown in continuously perfused double membrane bioreactors was investigated with respect to the final carbohydrate structures of a secretory recombinant glycoprotein. The human interleukin-2 (IL-2) mutant glycoprotein variant IL-Mu6, which bears a novel N-glycosylation site (created by a single amino acid exchange of Gln100 to Asn), was produced under different defined protein-free culture conditions in the presence or absence of either glutamine, NH4Cl, or glucosamine. Recombinant glycoprotein products were purified and characterized by amino acid sequencing and carbohydrate structural analysis using matrix-assisted laser desorption ionization time of flight mass spectrometry, high-pH anion-exchange chromatography with pulsed amperometric detection, and methylation analysis. In the absence of glutamine, cells secreted glycoprotein forms with preponderantly biantennary, proximal fucosylated carbohydrate chains (85%) with a higher NeuAc content (58%). Under standard conditions in the presence of 7.5 mM glutamine, complex-type N-glycans were found to be mainly biantennary (68%) and triantennary structures (33%) with about 50% containing proximal alpha1-6-linked fucose; 37% of the antenna were found to be substituted with terminal alpha2-3-linked N-acetylneuraminic acid. In the presence of 15 mM exogenously added NH4Cl, a significant and reproducible increase in tri- and tetraantennary oligosaccharides (45% of total) was detected in the secretion product. In glutamin-free cultures supplemented with glucosamine, an intermediate amount of high antennary glycans was detected. The increase in complexity of N-linked oligosaccharides is considered to be brought about by the increased levels of intracellular uridine diphosphate-GlcNAc/GalNAc. These nucleotide sugar pools were found to be significantly elevated in the presence of high NH3/NH4+ and glucosamine concentrations.

Diabetes mellitus and eating disorders: a multicenter study on the comorbidity of the two diseases

Because diet is a key issue in the treatment of diabetes mellitus, it is assumed that these patients are prone to eating disorders. In a multicenter study, we have therefore assessed the prevalence of eating disorders in 662 patients with insulin dependent diabetes mellitus (IDDM) (n = 340) and non-insulin-dependent diabetes mellitus (NIDDM) (n = 322). A two-stage study combining self-rating questionnaires and a standardized interview was carried out. We found a prevalence of eating disorders of 5.9% (lifetime prevalence of 10%), irrespective of gender and type of diabetes; 4.1% of the whole sample reported intentional insulin undertreatment or omission. When patients were stratified according to IDDM and NIDDM, there was no difference in the prevalence of all eating disorders (point prevalence 5.5% vs. 6.5%, lifetime prevalence 10.0% vs. 9.9%). Prevalence of bulimia nervosa (BN) was more frequent in IDDM patients (point prevalence 1.5% vs. 0.3%, lifetime prevalence 3.2% vs. 1.9%) and binge eating (BED) was more frequent in NIDDM patients (point prevalence 1.8% vs. 3.7%, lifetime prevalence 2.6% vs. 5.9%). We conclude that eating disorders seem to be equally frequent in IDDM and NIDDM patients. However, there might be different features of eating disorders in both types of diabetes.

[Autologous fibrin glue from preoperative blood or plasma donors]

Cryoprecipitate was prepared from autologous plasma donation (fresh frozen plasma). The composition of this cryoprecipitate (fibrinogen, factor XIII, fibronectin) meets the requirements for the fibrinogen component of a fibrin glue. The prepared glue has tensile strength values in dura mater gluing as good as the commercial tissue glues.

[Injury sequelae and late damage of dislocation fracture of the head of the tibia]

Consequences of injury as well as succeeding joint-impairment after fracture dislocation of the tibial head are analysed. Of 38 patients who had undergone operative therapy for fracture dislocation of the tibial head between 1982 and 1991, 30 were followed up after a mean of 6.3 years. With an average age of 46.8 years and a distribution between sexes of 26 men vs. 12 women, types II (17) and V (14) (classification acc. to Moore) clearly outweighed types III (3) and IV (3) as well as type I (1). Causes of injury were dominated by traffic accidents (22/38), 9 patients suffered from accompanying ipsi-, another 9 from contralateral injuries of their lower extremities. For evaluating follow-up results, both Lysholmscore and IKDC-knee-evaluation-form were employed. The latter qualifies the overall result as "normal", "nearly normal", "abnormal" or "severely abnormal". None of the knee-joints assessed was evaluated normal. There were only 2 patients to be qualified nearly normal, whereas 5 had to be assessed abnormal and 23 severely abnormal. These poor results were mainly due to persistent symptoms (pain, swelling, giving-way) (30/30), limited range of motion (27/30) as well as impairment of joint-stability (25/30). Our results stress the need for sophisticated operative and p.op. therapy of these complex injuries.

Mutations in the leader region of ribosomal RNA operons cause structurally defective 30 S ribosomes as revealed by in vivo structural probing

The biogenesis of functional ribosomes is regulated in a very complex manner, involving different proteins and RNA molecules. RNAs are not only essential components of both ribosomal subunits but also transiently interacting factors during particle formation. In eukaryotes snoRNAs act as molecular chaperones to assist maturation, modification and assembly. In a very similar way highly conserved leader sequences of bacterial rRNA operons are involved in the correct formation of 30 S ribosomal subunits. Certain mutations in the rRNA leader region cause severe growth defects due to malfunction of ribosomes which are assembled from such transcription units. To understand how the leader sequences act to facilitate the formation of the correct 30 S subunits we performed in vivo chemical probing to assess structural differences between ribosomes assembled either from rRNA transcribed from wild-type operons or from operons which contain mutations in the rRNA leader region. Cells transformed with plasmids containing the respective rRNA operons were reacted with dimethylsulphate (DMS). Ribosomes were isolated by sucrose gradient centrifugation and modified nucleotides within the 16 S rRNA were identified by primer extension reaction. Structural differences between ribosomes from wild-type and mutant rRNA operons occur in several clusters within the 16 S rRNA secondary structure. The most prominent differences are located in the central domain including the universally conserved pseudoknot structure which connects the 5', the central and the 3' domain of 16 S rRNA. Two other clusters with structural differences fall in the 5' domain where the leader had been shown to interact with mature 16 S rRNA and within the ribosomal protein S4 binding site. The other differences in structure are located in sites which are also known as sites for the action of several antibiotics. The data explain the functional defects of ribosomes from rRNA operons with leader mutations and help to understand the altered biogenesis pathway from mutations in an rRNA leader region to the formation of functionally defective ribosomes.

[Manual labor and Dupuytren disease. The results of a computerized survey in the field of iron metallurgy]

A survey was made among ironworkers to determine if manual work had a special influence on the onset of Dupuytren's disease. In 5,206 workmen examined, 196 were affected, and a careful study of their working conditions showed a definite correlation between hard manual work over many years and the occurrence of Dupuytren's disease, especially in the younger age group. We observed that familial arterial hypertension is a contributory factor. Although Dupuytren's disease cannot be considered as an occupational disease, its development, is favored by hard manual work for at least 10 years. The initiating role of trauma, especially a fracture of the wrist, is confirmed.

The ORF YBL042 of Saccharomyces cerevisiae encodes a uridine permease

The purpose of this work was to identify the function of an open reading frame called YBL042, found during the systematic sequencing of Saccharomyces cerevisiae's chromosome II. The YBL042 gene product shows 70% similarity with the uracil permease and the allantoin permease encoded by FUR4 and DAL4, respectively. The mutation constructed by disruption of this ORF is allelic to the FUI1 gene previously described as encoding the uridine permease but not cloned yet. A strain carrying the disrupted allele and a fui1 mutant exhibit the same phenotype as they do not grow on a medium containing uridine as the sole source of pyrimidines and as they are resistant to 10(-3) M 5-fluorouridine (5FUI), a toxic analog of uridine. Even though the FUI1 gene has a multicopy suppressor effect on uracil transport, its product does not seem to be involved in this transport, in contrast to the FUR4 gene product which is involved in uridine transport. Moreover, the FUI1 gene product does not play any role in allantoin transport.

On the chemical modification of pacemaker electrodes and patterned surface functionalization of planar substrates

We report on experiments towards the chemical modification of metal electrodes in order to enhance biocompatibility or improve cell adhesion properties. In the first example pacemaker electrodes were modified with a thin polysiloxane network which allowed for further derivatization with a poly(ethylene glycol) layer. The primary goal was to suppress inflammatory response of tissue after implantation of electrodes. FTIR, ESCA and a.c.-impedance spectroscopy show the integrity of the ultrathin membrane. No significant reduction of the electrode capacitance was observed, providing further proof for the deposition of a homogeneously thin membrane. The second example deals with the patterned chemical modification of planar surfaces. The goal was to eventually effect selective adhesion of electrosensitive cells above microelectrodes for stimulation and/or recording. First results demonstrate the compatibility of monolayer deposition techniques with common photolithography. It is thus possible to create surfaces with patterned chemical functionality. A gas-phase silylation process was developed in order to control more precisely surface hydration and reaction parameters than is possible with common solution-based silylation procedures.

IXDB, an X chromosome integrated database

The integrated X chromosome database (IXDB) is a repository for physical mapping data of the human X chromosome. Its current content is the result of a strict integration of data stemming from many different sources. The main features of IXDB include a flexible and extendible schema, a comfortable and fully cross-referenced WWW interface (http://ixdb.mpimg-berlin-dahlem.mpg.de ) and a graphical map viewer implemented in JAVA. The database stores objects used in physical mapping as well as the maps resulting from this work, but a strong emphasis is placed on recording experiments that connect objects together. This should greatly contribute to fulfilling one of the major goals of the database: to support the construction of an integrated physical, genetic, transcript and sequence map of the human X chromosome.

p27Kip1 is expressed transiently in developing myotomes and enhances myogenesis

Vertebrate skeletal muscle development is characterized by tight coupling of muscle differentiation with cell cycle arrest in G1/G0. Key regulators of G1 progression are the G1 cyclin-dependent kinases, their positive regulators, the G1 cyclins, and their negative regulators, the cyclin-dependent kinase inhibitors (CDIs). Here we show that p27Kip1 protein, a G1 CDI, is expressed in a prominent but transient wave in the developing myotomes of the mouse embryo. We relate its expression to expression of MyoD and myogenin proteins, which are determination and differentiation class myogenic regulatory factors, respectively. Functional assays showed that ectopic p27 expression can powerfully enhance the efficiency of MyoD-initiated muscle differentiation in cell culture. When considered together with the myotomal expression patterns of p18, p21, and p57, these results suggest a model in which p27 acts as a "trigger" CDI while myoblasts are exiting the cell cycle and initiating differentiation. At later times, when p27 protein has been down-regulated, it is proposed that accumulation of p18, p21, and p57 maintain the differentiated myocytes in a postmitotic state.