[In vitro fertilization and intracytoplasmic sperm injection: current medical aspects]. / In-vitro-Fertilisation und intrazytoplasmatische Spermieninjektion : Aktuelle medizinische Aspekte.

Since the delivery of the first baby conceived via in vitro fertilization (IVF) in 1978, IVF has become a standard procedure in sterility treatment. In Germany, 78,000 IVF/intracytoplasmic sperm injection (ICSI) cycles are performed annually with a delivery rate per embryo transfer of about 20 %. The cumulative delivery rate after three trials is more than 50 %. The main medical problems are the high rates of multiple pregnancies of more than 20 %, which carry an increased risk for mothers (preeclampsia) and children (preterm delivery, lung immaturity, brain problems). Also singleton babies after IVF are more often too small (small for gestational age, SGA) and delivered preterm. As a result, proper counselling is necessary. New laboratory methods have increased the success rate. Cryopreservation techniques such as vitrification are standard for freezing oocytes, pronuclear-stage oocytes and embryos if they are not needed during the current treatment cycle. Continuous observation of embryos by time-lapse imaging helps to identify the best embryos for transfer. The current legislation in the German embryo protection act (Embryonenschutzgesetz) is the main problem. It is unclear how many fertilized oocytes can be cultured to achieve a transfer of one to three embryos. The prohibition of oocyte donation and surrogacy are not comprehensible from a medical, psychological, and ethical point of view. Reimbursement of publicly insured patients is restricted in comparison with other European countries. Married couples receive half of the payment for three IVF/ICSI cycles; non-married couples receive no payment at all.

Mapping of B-cell epitopes in the nucleocapsid protein of Puumala hantavirus.

Hantavirus nucleocapsid protein (N) has been proven to induce highly protective immune responses in animal models. The knowledge on the mechanisms behind N-induced protection is still limited, although recent data suggest that both cellular and humoral immune responses are of importance. For a detailed B-cell epitope mapping of Puumala hantavirus (PUUV) N, we used recombinant N derivatives of the Russian strain CG18-20 and the Swedish strain Vranica/Hällnäs, as well as overlapping synthetic peptides corresponding to the Finnish prototype strain Sotkamo. The majority of a panel of monoclonal antibodies (mAbs) reacted with proteins derived from all included PUUV strains demonstrating the antigenic similarity of these proteins. In line with previous results, the epitopes of most mAbs were mapped within the 80 N-terminal amino acids of N. The present study further revealed that the epitopes of four mAbs raised against native viral N were located within amino acids 14-45, whereas one mAb raised against recombinant N was mapped to amino acids 14-39. Differences between the reactivity of the PUUV strains Vranica/Hällnäs and CG18-20 N suggested the importance of amino acid position 35 for the integrity of the epitopes. In line with the patterns obtained by the truncated recombinant proteins, mapping by overlapping peptides (PEPSCAN) confirmed a complex recognition pattern for most analyzed mAbs. Together, the results revealed the existence of several, partially overlapping, and discontinuous B-cell epitopes. In addition, based on differences within the same competition group, novel epitopes were defined.

First molecular evidence for Puumala hantavirus in Slovakia.

We report on the first Puumala hantavirus nucleotide sequence (strain Opina-916) amplified from a bank vole trapped in Slovakia, central Europe. Phylogenetic analysis of the S-segment sequence grouped the virus within the western/central European sublineage of Puumala virus. In the neighborhood of the rodent trapping site two cases of human infection by the Puumala virus were verified.

Dobrava hantavirus causes hemorrhagic fever with renal syndrome in central Europe and is carried by two different Apodemus mice species.

In central Europe, hemorrhagic fevers with renal syndrome (HFRS) in humans are caused by the hantavirus species Puumala (transmitted by voles) and a second, Hantaan-related species (transmitted by mice). The second virus could be identified as Dobrava virus. To date, 19 clinical cases of Dobrava infection have been found in Germany and Slovakia. All patients exhibited a mild/moderate clinical course and no case fatality occurred. Screening for infected rodents revealed that the striped field mouse (Apodemus agrarius) represents the main reservoir for Dobrava virus in central Europe. Nucleotide sequence comparisons and phylogenetic analysis based on complete and partial genomic S segment nucleotide sequences placed the Slovakian A. agrarius-derived hantavirus strains within the Dobrava species, forming a cluster on the Dobrava phylogenetic tree. In east Slovakia, a single Dobrava virus-infected yellow-necked mouse (Apodemus flavicollis) was trapped in a locality that predominantly showed Dobrava-infected A. agrarius. Comparison of the S segment sequence (nucleotides 381-935) revealed that the Dobrava strain from A. flavicollis shows only 84.3% nucleotide homology to A. agrarius-derived strains from this location but 96.3% homology to A. flavicollis-derived Dobrava strains from the Balkans (southeast Europe). Phylogenetic analysis of the partial S segment placed the A. flavicollis-derived Dobrava strain from Slovakia on a distinct Dobrava lineage (DOB-Af) together with the south-east European A. flavicollis-derived strains. The results indicate that Dobrava strains from A. agrarius (DOB-Aa) vs. A. flavicollis (DOB-Af) could develop different degrees of virulence in humans.

Short report: simultaneous occurrence of Dobrava, Puumala, and Tula Hantaviruses in Slovakia.

The prevalence of antibody to hantaviruses in Slovakia (serum panel n = 2,133) was lower in the western part (0.54%) and higher in the eastern part (1.91%) of the country and was found to be significantly enhanced in a group of forest workers from eastern Slovakia (5.88%). One-third of the IgM-negative convalescent phase sera from patients with hemorrhagic fever with renal syndrome exhibited antibodies reacting predominantly with Puumala virus antigen, while two-thirds had antibodies directed mainly against Hantaan virus antigen. Fine analysis of two Hantaan virus-reactive sera by a focus reduction neutralization test showed that Dobrava hantavirus was the source of these human infections. Initial results of rodent screening indicated the circulation of Dobrava virus in populations of striped field mice (Apodemus agrarius) in eastern Slovakia.

Recombination in Tula hantavirus evolution: analysis of genetic lineages from Slovakia.

To examine the evolution of Tula hantavirus (TUL), carried by the European common vole (Microtus arvalis and M. rossiaemeridionalis), we have analyzed genetic variants from Slovakia, the country where the virus is endemic. Phylogenetic analysis (PHYLIP) based on either partial (nucleotides [nt] 441 to 898) or complete N-protein-encoding sequences divided Slovakian TUL variants into two main lineages: (i) strains from eastern Slovakia, which clustered with Russian strains, and (ii) strains from western Slovakia situated closer to those from the Czech Republic. We found genetic diversity of 19% between the two groups and 4% within the western Slovakian TUL strains. Phylogenetic analysis of the 3' noncoding region (3'-NCR), however, placed the eastern Slovakian strains closer to those from western Slovakia and the Czech Republic, with a greater distance to the Russian strains, suggesting a recombinant nature of the S segment in the eastern Slovakian TUL lineage. A bootscan search of the S-segment sequences of TUL strains revealed at least two recombination points in the S sequences of eastern Slovakian TUL strains (nt 400 to 415 and around 1200) which agreed well with the pattern of amino acid substitutions in the N protein and deletions/insertions in the 3'-NCR of the S segment. These data suggest that homologous recombination events occurred in the evolution of hantaviruses.

Coding strategy of the S and M genomic segments of a hantavirus representing a new subtype of the Puumala serotype.

The hantavirus strain Vranica was previously reported to have been isolated from a bank vole in Bosnia-Hercegovina and associated with the occurrence of hemorrhagic fever with renal syndrome (HRFS) in humans. The complete cDNA nucleotide sequences of the small (S) and medium (M) genomic RNA segments of this virus were determined. Major open reading frames were found in the S and M segment between nucleotide positions 43 and 1341 coding for a polypeptide of 433 amino acid residues and between nucleotide positions 41 and 3,484 coding for 1,148 amino acid residues, respectively. The analysis and the alignment of the nucleotide and the derived amino acid sequences with known sequences of other hantavirus strains demonstrate that Vranica resembles Swedish strains and represents a new virus subtype of the Puumala serotype distinct from the subtypes represented by virus strains CG18-20 and Sotkamo.

Genetic characterization of a new hantavirus detected in Microtus arvalis from Slovakia.

A new hantavirus, called Malacky, has been identified in lung tissue specimens of a vole, Microtus arvalis, by the reverse transcriptase polymerase chain reaction (RT-PCR). The voles were trapped in a geographical area in Slovakia where hemorrhagic fever with renal syndrome (HFRS) is endemic in the human population. Sequence analysis of a major part of the S segment showed this virus to represent a new subtype within Tula, a new hantavirus genetic group defined very recently.

Mosaic pbpX genes of major clones of penicillin-resistant Streptococcus pneumoniae have evolved from pbpX genes of a penicillin-sensitive Streptococcus oralis.

Penicillin-resistant clinical isolates of Streptococcus pneumoniae contain mosaic penicillin-binding protein (PBP) genes that encode PBPs with decreased affinity for beta-lactam antibiotics. The mosaic blocks are believed to be the result of gene transfer of homologous PBP genes from related penicillin-resistant species. We have now identified a gene homologous to the pneumococcal PBP2x gene (pbpX) in a penicillin-sensitive Streptococcus oralis isolate M3 from South Africa that diverged by almost 20% from pbpX of penicillin-sensitive pneumococci, and a central sequence block of a mosaic pbpX gene of Streptococcus mitis strain NCTC 10712. In contrast, it differed by only 2-4% of the 1 to 1.5 kb mosaic block in pbpX genes of three genetically unrelated penicillin-resistant S. pneumoniae isolates, two of them representing clones of serotype 6B and 23F, which are prevalent in Spain and are also already found in other countries. With low concentrations of cefotaxime, transformants of the sensitive S. pneumoniae R6 strain could be selected containing pbpX genes from either S. mitis NCTC 10712 or S. oralis M3, demonstrating that genetic exchange can already occur between beta-lactam-sensitive species. These data are in agreement with the assumption that PBPs as penicillin-resistance determinants have evolved by the accumulation of point mutations in genes of sensitive commensal species.

Relatedness of penicillin-binding protein 1a genes from different clones of penicillin-resistant Streptococcus pneumoniae isolated in South Africa and Spain.

Penicillin-resistant strains of Streptococcus pneumoniae have been common in South Africa and Spain for several years. Multilocus enzyme electrophoresis identified one clone of capsular type 6B which was prevalent in Spain and another clone of type 23F that was present in both countries. Genes for penicillin-binding proteins (PBPs) in penicillin-resistant strains are often mosaics where parts of the pneumococcal genes are replaced by homologous genes from other species. We have compared the mosaic structures of the PBP 1a genes from the two clones as well as from genetically distinct South African isolates. Four classes of mosaic PBP 1a genes were found that contained blocks of sequences divergent by 6-22% from those of sensitive genes; two classes contained sequences coming from more than one external source. Data are presented showing that the PBP 1a genes from the 23F and the 6B clone are related, and that the two PBP 1a genes from the South African isolates are also related. We suggest that the type 23F clone originated in Spain prior to distribution into other continents.

Genetic relationships of penicillin-susceptible and -resistant Streptococcus pneumoniae strains isolated on different continents.

Sixty-six strains of Streptococcus pneumoniae isolated in different parts of the world, 46 resistant and 22 susceptible to penicillin, were subdivided by multilocus enzyme electrophoresis into 28 distinct electrophoretic types (ETs). The ETs to which penicillin-susceptible strains were assigned differed from those containing resistant isolates of the same serotype. Five common clones could be recognized among the penicillin-resistant bacteria by combining the ETs, the antigenic properties of penicillin-binding proteins PBP 1a and 2b, and the tetracycline and chloramphenicol resistance profiles. Two clones were found in Finland and were associated with capsular serotypes 6B and 23F, respectively. Two clones were from Spain (type 6B and 9V, respectively). The fifth clone was isolated in South Africa and in Spain and contained both serotype 23F isolates and one type 19F strain. The other resistant strains were represented by rare isolates distributed among 12 other ETs, confirming that resistance to penicillin has evolved by multiple branches. Because capsular type was mixed in several ETs, the results also demonstrate that it may vary among very closely related pneumococci.

Novel plasmids in clinical strains of Streptococcus pneumoniae.

Small plasmids were found in two clinical isolates of Streptococcus pneumoniae from Spain (strains 671 and 678) and in one strain (SpR) isolated in Germany. All three strains contained one plasmid (2.75 to 3.1 kb) which is related to the only previously described pneumococcal plasmid, pDP1. Strains 678 and SpR carried a second plasmid of 2.6 kb and 2.7 kb, respectively. These two plasmids hybridized neither with each other, nor with pDP1, demonstrating that they represent new types of plasmids not having been found in pneumococci before.

Cloning and characterization of the genes for ribosomal proteins L10 and L12 from Synechocystis Sp. PCC 6803: comparison of gene clustering pattern and protein sequence homology between cyanobacteria and chloroplasts.

The endosymbiont theory proposes that chloroplasts have originated from ancestral cyanobacteria through a process of engulfment and subsequent symbiotic adaptation. The molecular data for testing this theory have mainly been the nucleotide sequence of rRNAs and of photosystem component genes. In order to provide additional data in this area, we have isolated genomic clones of Synechocystis DNA containing the ribosomal protein gene cluster rplJL. The nucleotide sequence of this cluster and flanking regions was determined and the derived amino acid sequences were compared to the available homologous sequences from other eubacteria and chloroplasts. In Escherichia coli these two genes are part of a larger cluster, i.e., rplKAJL-rpoBC. In Synechocystis, the genes for the RNA polymerase subunit (rpoBC) are shown to be widely separated from the r-protein genes. The Synechocystis gene arrangement is similar to that in the chloroplast system, where the rpoBC1C2 and rplKAJL clusters are separated and located in two cell compartments, the chloroplast and the nucleus, respectively.