Two pregnancies after preimplantation genetic diagnosis for osteogenesis imperfecta type I and type IV

Osteogenesis imperfecta (OI) is an autosomal dominant genetic disorder characterized by the presence of brittle bones and decreased bone mass (osteopenia), as a result of mutations in the genes that encode the chains of type I collagen, the major protein of bone. The clinical features of the disease range from death in the perinatal period to normal life span with minimal increase in fractures. The present report describes two polymerase chain reaction (PCR)-based assays allowing preimplantation genetic diagnosis (PGD) on the one hand for OI type I, the mildest form, and on the other hand for OI type IV, which is intermediate in severity between OI type I and OI type III. In the couple referred for PGD for OI type I, the female partner carried a 1-bp deletion in exon 43 of the COL1A1 gene, resulting in a premature stop codon in exon 46. The synthesis of too little type I procollagen results from such a non-functional or COL1A1 null allele. In the other couple, referred for PGD for OI type IV, the male partner carried a G to A substitution in exon 19 of the COL1A2 gene, which results in an abnormal gene product due to an alphaGly247 (GGT) to Ser (AGT) substitution (G247S). Both mutations result in the loss of a specific restriction enzyme recognition site and can therefore be detected by PCR amplification followed by restriction fragment analysis. PCR amplification of genomic DNA of the parents-to-be with one of the two primers fluorescently labelled, followed by automated laser fluorescence (ALF) gel electrophoresis of the amplified and restricted fragments, allowed a distinction between the healthy and affected genotypes. PCR on single Epstein-Barr-virus (EBV)-transformed lymphoblasts resulted in acceptable amplification efficiencies (87% and 85% for OI type I and OI type IV respectively) and the allele drop-out (ADO) rate was assessed at 11.5% and 11.1% for OI type I and OI type IV respectively. With research blastomeres, 100% amplification rates were obtained and no contamination was observed in the blank controls, which validated the tests for clinical application. Embryos obtained after intracytoplasmic sperm injection (ICSI) were evaluated for the presence of the normal genotype of the non-affected parent. For OI type I, two frozen-thawed ICSI-PGD cycles and two fresh ICSI-PGD cycles were carried out for the same couple. The transfer of two unaffected embryos in the last cycle resulted in a twin pregnancy. A twin pregnancy was also achieved in one clinical ICSI-PGD cycle for OI type IV.     

Changes in ascorbic acid content and ascorbate peroxidase activity during the development of Acetabularia mediterranea

We cloned ras-related sequences from goldfish genomic libraries constructed as recombinants using the lambda phage. Restriction enzyme mapping of the clones obtained revealed three kinds of ras-related sequences among approximately 350,000 genomic clones. One of these clones was partially sequenced. Comparison with the nucleotide sequences of mammalian ras genes showed that the determined sequences covered the predicted amino acid coding regions and parts of the intervening regions. The predicted amino acid sequences of the cloned ras-related goldfish gene suggested that the coding region is localized separately in DNA, and that its exon-intron boundaries are exactly the same as those of corresponding mammalian genes. The nucleotide and amino acid sequences of the goldfish ras-related gene may have extensive homologies to mammalian p 21 protein. Among the three mammalian ras proteins, the predicted amino acid sequence of the sequenced ras-related goldfish clone is most closely homologous (96%) to the Kirsten ras protein. Differences in the predicted amino acid sequence were greatest in the sequence predicted from the fourth exon; fewer differences were found in the sequence from the third exon, and only slight or no differences were found in the sequence predicted for the first and second exons. The 12th and 61st amino acids from the N-terminal of the protein, which are thought to be critical positions for GTP binding and catalysis, are both conserved in the goldfish protein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Virus-host Interactions during Hepatitis C Virus Entry - Implications for Pathogenesis and Novel Treatment Approaches

Hepatitis C virus (HCV) is a member of the Flaviviridae family and causes acute and chronic hepatitis. Chronic HCV infection may result in severe liver damage including liver cirrhosis and hepatocellular carcinoma. The liver is the primary target organ of HCV, and the hepatocyte is its primary target cell. Attachment of the virus to the cell surface followed by viral entry is the first step in a cascade of interactions between the virus and the target cell that is required for successful entry into the cell and initiation of infection. This step is an important determinant of tissue tropism and pathogenesis; it thus represents a major target for antiviral host cell responses, such as antibody-mediated virus neutralization. Following the development of novel cell culture models for HCV infection our understanding of the HCV entry process and mechanisms of virus neutralization has been markedly advanced. In this review we summarize recent developments in the molecular biology of viral entry and its impact on pathogenesis of HCV infection, development of novel preventive and therapeutic antiviral strategies.     

Territorial defence of space and feeding sites by a plethodontid salamander

Two series of experiments were conducted, one in field enclosures and another in the laboratory, to test the hypothesis that the salamander Desmognathus monticola (family Plethodontidae) defends its refuges and feeding sites against conspecific intruders. When two identical cover sites were provided as refuges in the laboratory, residents and intruders occupied separate cover sites significantly more often than the same sites. Residents did not, however, show strong preference for the same site, nor did they consistently defend a specific site. When food supplements were provided consistently at the same cover sites in field enclosures, resident D. monticola occupied and defended the feeding sites significantly more frequently against intruders than the non-feeding cover sites. Individuals not receiving food supplements also excluded intruders from the occupied cover sites but did not defend a specific cover site. Residents in enclosures where no food supplements were provided were significantly more active at night, outside cover sites, than residents receiving food supplements. Individual D. monticola exhibit territoriality by excluding intruders from the refuges they occupy. Providing food supplements increases the site specificity of individuals and decreases the amount of time spent in nocturnal activity.     

The Non-Benzodiazepine Anxiolytic Drug Etifoxine Causes a Rapid,Receptor-Independent Stimulation of Neurosteroid Biosynthesis

Neurosteroids can modulate the activity of the GABA_A receptors, and thus affect anxiety-like behaviors. The non-benzodiazepine anxiolytic compound etifoxine has been shown to increase neurosteroid concentrations in brain tissue but the mode of action of etifoxine on neurosteroid formation has not yet been elucidated. In the present study, we have thus investigated the effect and the mechanism of action of etifoxine on neurosteroid biosynthesis using the frog hypothalamus as an experimental model. Exposure of frog hypothalamic explants to graded concentrations of etifoxine produced a dose-dependent increase in the biosynthesis of 17-hydroxypregnenolone, dehydroepiandrosterone, progesterone and tetrahydroprogesterone, associated with a decrease in the production of dihydroprogesterone. Time-course experiments revealed that a 15-min incubation of hypothalamic explants with etifoxine was sufficient to induce a robust increase in neurosteroid synthesis, suggesting that etifoxine activates steroidogenic enzymes at a post-translational level. Etifoxine-evoked neurosteroid biosynthesis was not affected by the central-type benzodiazepine (CBR) receptor antagonist flumazenil, the translocator protein (TSPO) antagonist PK11195 or the GABA_A receptor antagonist bicuculline. In addition, the stimulatory effects of etifoxine and the triakontatetraneuropeptide TTN, a TSPO agonist, were additive, indicating that these two compounds act through distinct mechanisms. Etifoxine also induced a rapid stimulation of neurosteroid biosynthesis from frog hypothalamus homogenates, a preparation in which membrane receptor signalling is disrupted. In conclusion, the present study demonstrates that etifoxine stimulates neurosteroid production through a membrane receptor-independent mechanism.     

Taxonomic studies in the genus Peristylus (Orchidaceae) in Thailand

A taxonomic review of the Thai species of the orchid genus Peristylus is presented. Seventeen species are recognised, five of them new to Thailand. Peristylus rigidus and P. phuwuaensis are endemic species, new to science, and the widespread P. maingayi and P. mannii have recently been newly recorded in the country. In addition, two further collections do not match any known Thai species, but very much resemble P. nematocaulon from the Himalayas and China. The present study will form the basis for the taxonomic account of Peristylus in the Flora of Thailand.     

Similar qualitative and quantitative changes of mitochondrial respiration following strength and endurance training in normoxia and hypoxia in sedentary humans

Endurance and strength training are established as distinct exercise modalities, increasing either mitochondrial density or myofibrillar units. Recent research, however, suggests that mitochondrial biogenesis is stimulated by both training modalities. To test the training "specificity" hypothesis, mitochondrial respiration was studied in permeabilized muscle fibers from 25 sedentary adults after endurance (ET) or strength training (ST) in normoxia or hypoxia [fraction of inspired oxygen (Fi(O(2))) = 21% or 13.5%]. Biopsies were taken from the musculus vastus lateralis, and cycle-ergometric incremental maximum oxygen uptake (VO(2max)) exercise tests were performed under normoxia, before and after the 10-wk training program. The main finding was a significant increase (P < 0.05) of fatty acid oxidation capacity per muscle mass, after endurance and strength training under normoxia [2.6- and 2.4-fold for endurance training normoxia group (ET(N)) and strength training normoxia group (ST(N)); n = 8 and 3] and hypoxia [2.0-fold for the endurance training hypoxia group (ET(H)) and strength training hypoxia group (ST(H)); n = 7 and 7], and higher coupling control of oxidative phosphorylation. The enhanced lipid oxidative phosphorylation (OXPHOS) capacity was mainly (87%) due to qualitative mitochondrial changes increasing the relative capacity for fatty acid oxidation (P < 0.01). Mitochondrial tissue-density contributed to a smaller extent (13%), reflected by the gain in muscle mass-specific respiratory capacity with a physiological substrate cocktail (glutamate, malate, succinate, and octanoylcarnitine). No significant increase was observed in mitochondrial DNA (mtDNA) content. Physiological OXPHOS capacity increased significantly in ET(N) (P < 0.01), with the same trend in ET(H) and ST(H) (P < 0.1). The limitation of flux by the phosphorylation system was diminished after training. Importantly, key mitochondrial adaptations were similar after endurance and strength training, regardless of normoxic or hypoxic exercise. The transition from a sedentary to an active lifestyle induced muscular changes of mitochondrial quality representative of mitochondrial health.     

Model-based design and control of a small-scale integrated continuous end-to-end mAb platform

A continuous integrated bioprocess available from the earliest stages of process development allows for an easier, more efficient and faster development and characterization of an integrated process as well as production of small-scale drug candidates. The process presented in this article is a proof-of-concept of a continuous end-to-end monoclonal antibody production platform at a very small scale based on a 200 ml alternating tangential flow filtration perfusion bioreactor, integrated with the purification process with a model-based design and control. The downstream process, consisting of a periodic twin-column protein A capture, a virus inactivation, a CEX column and an AEX column, was compactly implemented in a single chromatography system, with a purification time of less than 4 hr. Monoclonal antibodies were produced for 17 days in a high cell density perfusion culture of CHO cells with titers up to 1.0 mg/ml. A digital twin of the downstream process was created by modelling all the chromatography steps. These models were used for real-time decision making by the implementation of control strategies to automatize and optimize the operation of the process. A consistent glycosylation pattern of the purified product was ensured by the steady state operation of the process. Regarding the removal of impurities, at least a 4-log reduction in the HCP levels was achieved. The recovery yield was up to 60%, and a maximum productivity of 0.8 mg/ml/day of purified product was obtained.     

Spontaneous ophthalmic lesions in young Swiss mice.

BACKGROUND AND PURPOSE: Outbred mice are frequently used in toxicity evaluation. Due to their small size, ophthalmologic examination of such animals is difficult with regard to restraint and use of instruments designed for human medicine. The clinical appearance and incidence of spontaneous ophthalmic lesions should be helpful in selecting mice for toxicity studies and allow distinction between intercurrent spontaneous ocular changes and those attributable to drugs or chemicals. METHODS: Pretest ophthalmologic examinations of about 3,000 4- to 5-week-old Swiss mice, Crl:CD1 (ICR)BR, conducted in 1995 and 1996, provided information about spontaneous ocular changes and their incidence. Eye evaluations were performed after pupil dilatation (0.5% tropicamide instillation), using indirect ophthalmoscopy, and when indicated, a portable slit lamp. RESULTS: Lenticular opacities and heterogeneity/prominence were the most common findings (up to 19%) in the anterior segment. Abnormalities of the cornea and iris were detected in up to 4% of mice. Hyaloid artery remnant, as well as isolated cases of floating bodies or hemorrhage, was observed in the vitreous of 12 to 17% of mice. Approximately 2 to 4% of mice had colobomatous fundus, retinal fold, or retinal atrophy. A few mice had chorioretinal atrophy, hemorrhage, or abnormal pattern of the retinal vasculature. Remaining findings consisted of incomplete palpebral fissure, microphthalmia, exophthalmia, ophthalmic hemorrhage, and scleral mass. CONCLUSIONS: Due to severity of the condition or interference with ocular examination, affected mice should be eliminated from experimental studies. Hence, pretest ocular examinations of mice are indicated in safety-assessment toxicity studies.