Genetic mapping of chronic childhood-onset spinal muscular atrophy to chromosome 5q11.2-13.3

SPINAL muscular atrophy (SMA) describes a group of heritable degenerative diseases that selectively affect the alpha-motor neuron. Childhood-onset SMAs rank second in frequency to cystic fibrosis among autosomal recessive disorders, and are the leading cause of heritable infant mortality. Predictions that genetic heterogeneity underlies the differences between types of SMA, together with the aggressive nature of the most-severe infantile form, make linkage analysis of SMA potentially complex. We have now analysed 13 clinically heterogeneous SMA families. We find that 'chronic' childhood-onset SMA (including intermediate SMA or SMA type II, and Kugelberg-Welander or SMA type III) is genetically homogeneous, mapping to chromosomal region 5q11.2-13.3.

Analysis of gene transcription in bovine nuclear transfer embryos reconstructed with granulosa cell nuclei

The low efficiency of animal production using somatic cell nuclear transfer procedures is considered to be the result of an incomplete reprogramming of the donor somatic cell nucleus, which leads to a lack of, or abnormal expression of developmentally important genes. However, our current understanding of the process of somatic cell nuclear reprogramming and its effect on gene expression is limited. In this study, we compare the transcription patterns of six developmentally important genes, Oct4, IL6, FGF2, FGF4, FGFr2, and gp130 in single in vitro fertilized (IVF) and nuclear transfer embryos reconstructed using granulosa cells for the donor nuclei. Similar patterns of transcription were detected for Oct4, FGF2, and gp130 in IVF and nuclear transfer embryos during the preimplantation stages of development. However, a number of morula- and blastocyst-stage embryos derived from nuclear transfer procedures showed abnormal transcription of IL6, FGF4, and FGFr2. Previous studies have demonstrated that these three genes play an important role in implantation, early postimplantation development, or both in the mouse. Therefore, the aberrant transcription patterns detected in nuclear transfer embryos may lead to a reduction in embryo viability.

Peptide signal molecules and bacteriocins in Gram-negative bacteria: a genome-wide in silico screening for peptides containing a double-glycine leader sequence and their cognate transporters

Quorum sensing (QS) in Gram-negative bacteria is generally assumed to be mediated by N-acyl-homoserine lactone molecules while Gram-positive bacteria make use of signaling peptides. We analyzed the occurrence in Gram-negative bacteria of peptides and transporters that are involved in quorum sensing in Gram-positive bacteria. Many class II bacteriocins and inducing factors produced by lactic acid bacteria (LAB) and competence stimulating peptides (CSPs) synthesized by streptococci are processed by their cognate ABC-transporters during their secretion. During transport, a conserved leader sequence, termed the double-glycine motif (GG-motif), is cleaved off by the N-terminal domain of the transporter, which belongs to the Peptidase C39 protein family. Several peptides containing a GG-motif were recently described in Gram-negative bacteria (Trends Microbiol 2001;9:164-8). To screen for additional putative GG-motif containing peptides, an in silico strategy based on MEME, HMMER2.2 and Wise2 was designed. Using a curated training set, a motif model of the leader peptide was built and used to screen over 120 fully sequenced bacterial genomes. The screening methodology was applied at the nucleotide level as probably many small peptide genes have not been annotated and may be absent from the non-redundant databases. It was found that 33% of the screened genomes of Gram-negative bacteria contained one or more transporters carrying a Peptidase C39 domain, compared to 44% of the genomes of Gram-positive bacteria. The transporters can be subdivided into four classes on the basis of their domain organization. Genes coding for putative peptides containing 23-142 amino acids and a GG-motif were found in close association with genes coding for Peptidase C39 domain containing proteins. These peptides show structural similarity to bacteriocins and peptide pheromones of Gram-positive bacteria. The possibility of signal transduction based on peptide signaling in Gram-negative bacteria is discussed.

Comparison of gene transcription in cloned bovine embryos produced by different nuclear transfer techniques

The efficiency of animal production using cloning technology is still relatively low and research to determine a more efficient nuclear transfer procedure is ongoing. One approach which may be informative in assessing the viability of nuclear transfer embryos is the analysis of embryonic gene expression. Using RT-PCR techniques we have previously detected the aberrant expression of FGF4, FGFr2 and IL6 in a significant proportion of bovine granulosa cell-derived nuclear transfer embryos, which correlated with a limited developmental potential in vivo. In order to analyse the effect of different donor cell nuclei on embryonic gene expression we have now analysed the expression of these genes in nuclear transfer embryos reconstructed with fetal epithelial cell nuclei. In addition, we have compared the expression of these genes in bovine nuclear transfer embryos produced by cell fusion or direct injection with variations in the timing of oocyte activation. In all nuclear transfer embryos analysed, FGFr2 and IL6 transcripts were detected at a similar rate to that in IVF embryos. However, the absence of FGF4 transcripts was again evident in a large proportion of nuclear transfer embryos and most significantly in those embryos whose development was activated almost immediately following the transfer of the donor nucleus. The results demonstrate the effects that different donor cell lines and different nuclear transfer procedures may have on the expression of developmentally important genes in nuclear transfer embryos.

XIST expression in human oocytes and preimplantation embryos

During mouse preimplantation development, the exclusive expression of the Xist gene from the paternally inherited allele is thought to play a role in the inactivation of the paternally inherited X chromosome in the extra-embryonic cell lineages of the developing female embryo. Recently, inactivation of the paternally inherited X chromosome has also been shown to occur in the extraembryonic cell lineages of the human female conceptus. In this paper, we determine whether the pattern of XIST expression in human preimplantation embryos is similarly correlated with paternal X inactivation. We developed procedures sensitive to the single cell, for the simultaneous analysis of XIST and HPRT expression and of sexing, initially using human fibroblast cells. Application of these procedures to human cleavage-stage embryos derived by in vitro fertilization revealed a pattern of XIST expression different from that in the mouse. Transcripts of the XIST gene were detected as early as the 1-cell zygote and, with increasing efficiency, through to the 8-cell stage of preimplantation development. In addition, transcripts of XIST were detected in both male (hence from the maternally inherited allele) and female preimplantation embryos. This pattern of expression is not consistent with a role for the early expression of the XIST gene in the choice of paternal X inactivation in the extraembryonic cell lineages of the developing human embryo.

Hydroxypropylmethylcellulose (HPMC) as emulsifier for submicron emulsions: influence of molecular weight and substitution type on the droplet size after high-pressure homogenization

Hydroxypropylmethylcellulose (HPMC) is a known emulsifier as well as a common viscosity enhancer in eye drops. Therefore, HPMC stabilized emulsions appear as interesting drug carriers for ophthalmic use and as a suitable treatment of dry eye syndrome. Since submicron emulsions are known to have an improved drug delivery, attempts were made to reduce the emulsion's droplet size by high-pressure homogenization. Droplet size was dependent on the homogenization pressure and the polymer content. Differences were found between emulsions stabilized with higher and lower molecular weight HPMC. Smaller droplet sizes were obtained with the shorter chained HPMC. No considerable influence of the substitution type was observed.

A hypothesis: the conjunction of soldiers, gas, pigs, ducks, geese and horses in Northern France during the Great War provided the conditions for the emergence of the “Spanish” influenza pandemic of 1918–1919

The Great Influenza Pandemic of 1918-1919 was a cataclysmic outbreak of infection wherein over 50 million people died worldwide within 18 months. The question of the origin is important because most influenza surveillance at present is focussed on S.E. Asia. Two later pandemic viruses in 1957 and 1968 arose in this region. However we present evidence that early outbreaks of a new disease with rapid onset and spreadability, high mortality in young soldiers in the British base camp at Etaples in Northern France in the winter of 1917 is, at least to date, the most likely focus of origin of the pandemic. Pathologists working at Etaples and Aldershot barracks later agreed that these early outbreaks in army camps were the same disease as the infection wave of influenza in 1918. The Etaples camp had the necessary mixture of factors for emergence of pandemic influenza including overcrowding (with 100,000 soldiers daily changing), live pigs, and nearby live geese, duck and chicken markets, horses and an additional factor 24 gases (some of them mutagenic) used in large 100 ton quantities to contaminate soldiers and the landscape. The final trigger for the ensuing pandemic was the return of millions of soldiers to their homelands around the entire world in the autumn of 1918.

Antigenic and sequence analysis of H3 influenza virus haemagglutinins from pigs in Italy

To investigate the possible mechanism of maintenance of old human influenza A (H3N2) viruses in pigs, the haemagglutinins (HAs) of seven isolates from swine were studied by analysis of nucleotide and deduced primary amino acid sequences, as well as reactivity of the HA molecule to chicken antisera and monoclonal antibodies. The swine HAs were closely similar to the HA of the A/Victoria/3/75 human variant as regards antigenic and molecular characteristics. These findings are consistent with the hypothesis that the swine HA genes were transmitted from an early human H3 virus to pigs, where they survived with limited mutations over a period of 5 years. The sequence data were also compared with swine H3 sequences to investigate genetic relationships between the H3 genes from swine viruses isolated in different geographical areas. An evolutionary tree, constructed from the nucleotide sequences of viruses isolated from pigs in China and in Italy, illustrated that, depending on the country of their isolation, the HA genes of swine influenza A (H3N2) viruses have different origins, e.g. human and avian, and evolved independently in different lineages. The study provides direct support for the hypothesis that pigs might serve as a 'mixing vessel' for the generation of pandemic strains of human influenza viruses.

Comparison of two palpation, four radiographic and three ultrasound methods for early detection of mild to moderate canine hip dysplasia

Hip joint laxity was evaluated in Golden Retriever (n = 60), Labrador Retriever (n = 23), and Labrador/Golden Retriever mix (n = 24) puppies. Ortolani and Bardens maneuvers, four radiographic measurement indices and three dynamic ultrasonographic measurements were used. Each puppy was evaluated twice; at 6.5 to 9 and 43 to 79 weeks of age. These nine methods were compared for accuracy in predicting the development of canine hip dysplasia with or without degenerative joint disease by a median age of 16 months. The Bardens maneuver was a significant predictor of canine hip dysplasia/+/-degenerative joint disease for Golden Retriever puppies, however, it was not a reliable predictor for the other two breeds. Norberg angle measurements taken with femurs in a neutral position with hips distracted (PennHip position) was a significant predictor of degenerative joint disease in two breeds, but not in Golden Retriever puppies. Ultrasound measurement was a reliable predictor of hip canine hip dysplasia/+/-degenerative joint disease for Labrador/Golden Retriever mix puppies, but was not reliable for the other two breeds. Palpation, radiographic, and ultrasonographic methods of evaluating hip joint laxity in puppies at 6.5 to 9 weeks of age were not consistently reliable for all three breeds in predicting hip dysplasia with or without degenerative joint disease at one year of age. A strong association was found between Norberg angle and degenerative joint disease occurrence, as well as between distraction index (PennHip) and degenerative joint disease occurrence when measured at 52 to 79 weeks of age, but not when measured at 6.5 to 9 weeks of age in these breeds. These results emphasize the difficulty of early detection of mild hip dysplasia in the dog.

Localization, expression and genomic structure of the gene encoding the human serine protease testisin

Testisin is a recently identified human serine protease expressed by premeiotic testicular germ cells and is a candidate tumor suppressor for testicular cancer. Here, we report the characterization of the gene encoding testisin, designated PRSS21, and its localization on the short arm of human chromosome 16 (16p13.3) between the microsatellite marker D16S246 and the radiation hybrid breakpoint CY23HA. We have further refined the localization to cosmid 406D6 in this interval and have established that the gene is approximately 4. 5 kb in length, and contains six exons and five intervening introns. The structure of PRSS21 is very similar to the human prostasin gene (PRSS8) which maps nearby on 16p11.2, suggesting that these genes may have evolved through gene duplication. Sequence analysis showed that the two known isoforms of testisin are generated by alternative pre-mRNA splicing. A major transcription initiation site was identified 97 nucleotides upstream of the testisin translation start and conforms to a consensus initiator element. The region surrounding the transcription initiation site lacks a TATA consensus sequence, but contains a CCAAT sequence and includes a CpG island. The 5'-flanking region contains several consensus response elements including Sp1, AP1 and several testis-specific elements. Analysis of testisin gene expression in tumor cell lines shows that testisin is not expressed in testicular tumor cells but is aberrantly expressed in some tumor cell lines of non-testis origin. These data provide the basis for identifying potential genetic alterations of PRSS21 that may underlie both testicular abnormalities and tumorigenesis.

Partial "repair" of defective NEF genes in a long-term nonprogressor with human immunodeficiency virus type 1 infection

A 36-bp deletion close to the 5' end of NEF that impaired Nef function was found in a long-term nonprogressor with human immunodeficiency virus type 1 (HIV-1) infection. Forms containing an adjacent duplication of 33 bp were also frequently observed. The duplication showed no homology to the deleted region but restored the overall length of the first variable loop of Nef. NEF alleles carrying the duplication were active in class I major histocompatibility complex (MHC-I) down-modulation and enhancement of virus infectivity. However, they showed little activity in CD4 down-regulation and were unable to stimulate viral replication in human peripheral blood mononuclear cells. Our study indicates that the enhancement of virion infectivity and the stimulation of HIV-1 replication in lymphocytes are distinct functions of Nef. Our findings also illustrate the capacity for repair of attenuating deletions in HIV-1 infection and suggest that a selective pressure for Nef-mediated MHC-I down-modulation and/or enhancement of virion infectivity exists.

The influence of posture on the pharmacokinetics of orally administered nifedipine

1. Nifedipine (20 mg as capsules) and soluble paracetamol (1 g) were co-administered to eight healthy young volunteers on three separate occasions, following which in random order they stood, lay on their left side or lay on their right side for 4 h. 2. The time to maximum plasma concentration of paracetamol was significantly lower when standing or lying on the right side compared with recumbent left, indicating more rapid gastric emptying. 3. The times to maximum plasma concentrations of nifedipine and its metabolite produced at first pass were reduced when standing or lying on the right side. These postures were associated with significantly higher peak plasma concentrations and AUC values of nifedipine but not of its nitropyridine metabolite. 4. The increase in heart rate following nifedipine administration was significantly greater when lying on the right side compared with the left. 5. The data are consistent with transient saturation of first pass metabolism of nifedipine with postures which favour rapid gastric emptying. The results demonstrate the importance of defining the precise posture in studies in which pharmacokinetic and pharmacodynamic measurements are made on drugs which are absorbed rapidly and are subject to presystemic elimination.

Transcription of tissue-specific genes in human preimplantation embryos

We have recently detected de-novo transcripts of the predominantly muscle-specific myotonin protein kinase gene in human preimplantation embryos from the 1-cell to the 4-cell stages. Others have shown de-novo transcripts of the Y-linked genes, ZFY and SRY, in the 1-cell zygote. In order to assess the significance of early transcription of these predominantly tissue-specific genes in preimplantation development, we have analysed individual human oocytes and preimplantation embryos for the presence of transcripts of two further tissue-specific genes, alpha-globin and beta-globin, and two house-keeping genes, HPRT and APRT. Reverse transcriptase polymerase chain reaction assays were developed to the required single cell sensitivity, using human red blood cells and fibroblasts, prior to their application to human oocytes and embryos. As expected, transcripts of the house-keeping genes, HPRT and APRT, were detected at all stages of preimplantation development. Transcripts of 'tissue-specific' alpha-globin were readily detected in preimplantation embryos from the 1-cell stage. However, transcripts of beta-globin were detected only rarely (in only one of the 11 embryos analysed). This difference may be due to the fact that alpha-globin contains a CpG island. A survey of the data on gene expression in early human development suggests that CpG-island-containing genes may be expressed in preimplantation embryos. Expression of these genes in gametes and early embryos may be involved in the survival of CpG islands in evolution.

cDNA libraries from single human preimplantation embryos

In this paper, the construction, evaluation, and application of cDNA libraries from eight unfertilized oocytes and single four-cell-, seven-cell-, and blastocyst-stage embryos are described. Rapid, reproducible, and efficient procedures for the construction of PCR-based cDNA libraries from fewer than 10 cells were first developed in small populations of fibroblast cells. The human embryo libraries display complexities sufficient (between 10(5) and 10(6) clones) to represent the entire active gene population at these early stages of human development. The ubiquitous cytoskeletal elements, beta-actin, keratin-18, and alpha-tubulin, were detected at the expected frequency. Sequencing of consecutively picked random clones, without selection, showed the presence of a variety of sequences, such as the human transposable element, LINE-1 and Alu repeat sequences, housekeeping genes, and tissue-specific genes, such as alpha-globin and FMR-1. In addition to cDNAs corresponding to known ESTs (expressed sequence tags) in the GenBank and dbEST databases, a high proportion of novel sequences were detected. Applications of the libraries to several areas of interest, such as expression of CpG-island-containing "tissue-specific" genes, developmental genes expressed in a stage-specific manner, and a search for monoallelic expression of imprinted genes, are described. The libraries are a valuable resource for the study of gene expression during human preimplantation development and obviate the need for research on the human embryos themselves.

Hypericin for visualization of high grade gliomas: first clinical experience

AIMS

We aimed to demonstrate that Hypericin, a component of St. Johns Wort, selectively visualizes malignant gliomas. Hypericin is known as one of the most powerful photosensitizers in nature with excellent fluorescent properties.

METHODS

In five patients with a recurrence of a malignant glioma a newly developed water soluble formulation of hypericin was given intravenously (0.1 mg/kg body weight) 6 h before the surgical procedure. Tumor resection was performed under white light and fluorescence mode. The intensity grade of the tissue fluorescence was categorisized by the surgeon in three grades, highly fluorescent, weakly fluorescent and not fluorescent. In these areas tissue samples were taken and investigated by two blinded independent neuropathologists. Tissue samples were histologically classified differentiating between tumor tissue, tumor necrosis, tissue with scattered tumor cells and normal brain tissue.

RESULTS

In all patients tumor tissue was clearly distinguishable by its typically red fluorescence color from normal brain tissue which was colored blue under a special fluorescent filter. Histological evaluation of the 110 tissue samples showed a specificity of 100% and sensitivity of 91% for one of the two neuropathologists, whereas specificity for second pathologist was 90% and sensitivity 94%. The i.v. application of Hypericin proofed to be safe in all cases and there were no side effects observed.

CONCLUSION

Hypericin in its water soluble form is a well tolerated drug. In addition to its high photosensitizing properties hypericin will open up interesting new therapeutic possibilities especially when used in combination with fluorescence detection and simultaneously photodynamic therapy.

Plasma neuropeptide-Y levels, monoamine metabolism, electrolyte excretion and drinking behavior in children with attention-deficit hyperactivity disorder

Against a background of (a) increased drinking behavior in children with attention-deficit hyperactivity disorder (ADHD); (b) the parallel between some behaviors associated with ADHD and hypertension; (c) the use of the spontaneously hypertensive rat as a model for ADHD; and (d) similarities in the changes of neuropeptide Y (NPY) and catecholamine in studies of hypertension and drinking, NPY, catecholamines and electrolyte balance were compared in the plasma and urine of healthy children and those with ADHD. Drinking was monitored during 3 h of neuropsychological tests over 2 days in 14 ADHD and nine healthy children. Patients drank four times as much water and showed twice the levels of NPY found in controls. In controls there were positive and in patients there were negative relationships for NPY with drinking and restless behavior. Patients' plasma levels of norepinephrine (NE) and epinephrine were slightly elevated, but urinary levels of NE and the serotonin metabolite were markedly increased. Urinary excretion rates for sodium (not potassium), phosphate and especially calcium were decreased in patients even after covarying for less urine production in the ADHD group. NPY levels were inversely related to calcium excretion and drinking was inversely related to circulating sodium. Increases of drinking and circulating NPY in ADHD children and decreased electrolyte excretion may reflect a common disturbance in metabolic homeostasis.

Influence of pH adjustment on microcapsules obtained from complex coacervation of gelatin and acacia

The coacervation behaviour of commercial grade gelatin and acacia mixtures was studied with five different acids to adjust the coacervation pH, i.e. HCl, HNO3, H2SO4, acetic acid, and citric acid. The electrical equivalence pH value (EEP) of the polymer mixture was determined by means of a streaming current detector (SCD). With all acids--except H2SO4--maximum coacervate yield was observed at the EEP. Using H2SO4 the EEP was found at a lower pH value than compared with the point of maximum coacervate yield. The quantity of coacervate at the EEP was significantly reduced in the presence of H2SO4 whereas with all other acids, almost no differences were found. The dependence of the coacervate volume on the added amount of acid did not change in parallel to the dry coacervate yield and there was no coincidence of the maximum coacervate volume and the EEP. The barrier properties of the capsule shells of corresponding microcapsules using indomethacin as a model drug were examined by dissolution studies. Indomethacin microcapsules showed the slowest release rate when the coacervation pH was adjusted to the EEP and not to the pH of maximum coacervate yield. As expected from the coacervation behaviour, dissolution profiles of the microcapsules were quite similar even when different acids were used for pH adjustment.

Scientific lessons from the first influenza pandemic of the 20th century

Re-analysis of the influenza pandemic of 1918 has given reassurance about a rather low reproductive number (R(o)), a prolonged herald wave of virus and that the skewed mortality towards the young adult could be a singularly unique event dependent upon previous infection history, perhaps not to be repeated in a future pandemic. Over 99% of those who contracted the virus survived, in spite of the absence of antivirals, vaccine and antibiotics for the secondary bacteria infections which probably accounted for one-third of the 50 million deaths. Therefore, in spite of a three-fold population increase since 1918 and 100 thousand plane journeys daily, judicious and careful planning together with a stockpile of antiviral drugs, oseltamivir, zanamivir and M2 blockers and a generic H5N1 vaccine, and application of hygiene would be expected to reduce mortality in a new pandemic, to figures significantly less than 1918.

In vitro skin permeation and penetration of nonivamide from novel film-forming emulsions

The purpose of this study was to develop film-forming emulsions (FFE) facilitating long-term treatment of chronic pruritus with capsaicinoids. To this end, oil-in-water emulsions, which comprise dispersions of sustained-release polymers, were examined. Such emulsions form a film when applied to the skin and encapsulate the oily drug solution in a dry polymeric matrix. Permeation of the antipruritic drug nonivamide (NVA) is controlled by the matrix. Permeation rates of NVA from FFE and its concentration in the skin are equivalent to those achieved with a conventional semisolid formulation, but can be maintained for a longer period of time. FFE may therefore improve the treatment of chronic pruritus with capsaicinoids by enhancing patient compliance by means of a sustained-release regimen.