Limitations of homology searching for identification of T-cell antigens with library derived mimicry epitopes.

Mimicry epitopes that are recognized by T-cells can be identified through screening of synthetic peptide libraries. We have shown that these mimicry epitopes share sequence similarity with the corresponding natural epitopes and that mimicry sequences can be used for the definition of protein derived T-cell epitopes from databases. This can be done by either homology searching or pattern searching. Here we discuss the advantages and disadvantages of homology searching as an alternative for the generally applicable recognition pattern approach. We show that only for part of the library derived mimicry epitopes, the degree of similarity to the natural epitope may be high enough for successful homology searching in small databases.     

An experimental marker vaccine and accompanying serological diagnostic test both based on envelope glycoprotein E2 of classical swine fever virus (CSFV)

Envelope glycoprotein E2 is the most immunogenic protein of classical swine fever virus (CSFV). In a proposed model of the antigenic structure of E2, the N-terminal half of E2 forms two independent structural antigenic units, A and BC. E2 without transmembrane region (E2-TMR) is expressed and secreted into the medium of insect cells by use of the baculovirus expression system. The immune response induced by E2 protects pigs against CSFV. Recently, we showed that the protective immune response to a homologous CSFV challenge can be induced by a single unit, A or BC, of E2. An indirect blocking ELISA, or complex trapping blocking assay (CTB) based on both units is routinely used worldwide for serological diagnosis of CSFV infections. Here we show that E2-TMR is secreted into the medium as a homodimer. This E2 homodimer was used to develop a CTB detecting antibodies directed against one immunogenic unit of E2. Thus, the protective immune response induced by E2 containing one unit was not detected with a modified CTB based on the other unit, whereas immune responses induced by a variety of low virulent CSFV strains were detected with such a modified CTB. These results indicate that a deletion E2 protein in combination with a modified CTB are feasible as CSF marker vaccine and accompanying differentiating diagnostic test.     

Epidemiology of child deaths due to drowning in Matlab, Bangladesh.

BACKGROUND: Although the recent decline in child mortality in Bangladesh is remarkable, death from causes other than infectious diseases and malnutrition remains an important component of child mortality. Death from drowning of children can be expected to be a problem in Bangladesh given the geographical features of the country. OBJECTIVE: The objectives of this study are to determine the trend, pattern, and correlates of drowning deaths. METHODS: Data are presented on deaths of children (1-4 years) due to drowning derived from a longitudinal, population-based surveillance system in operation in a rural area of Bangladesh in 1983-1995. Moreover, a case-control study was carried out to identify the risk factors associated with drowning. RESULTS: Deaths due to drowning ranged from about 10% to 25% of child deaths during 1983-1995. The absolute risk of dying from drowning remained almost the same over the study period but the proportion of drownings to all causes of death has increased. Drowning is especially prevalent in the second year of life. Age of the mother and parity have a significant impact on drowning. The risk of dying from drowning increases with the age of mother and much more sharply with the number of living children in the family. Two socioeconomic variables did not have an influence on the risk of drowning. CONCLUSIONS: A substantial proportion of child deaths could be averted if parents and other close relatives paid more attention to the safety of children. The Child Health Programme of the Ministry of Health and Family Welfare of Bangladesh should develop health education programmes for villagers alerting them to the dangers of drowning and measures to prevent it.     

Understanding the feasibility of integrated care: a rival viewpoint on the influence of actions and the institutional context

There is in Europe growing awareness that the delivery of integrated care is required to meet the demands of an increasing number of patients with multiple problems. It is also clear that the provision of integrated care is difficult to achieve. As yet, the debate about the circumstances enabling or hindering provision is not settled. The objective of this article is to generate more knowledge on this issue. It is often assumed that the feasibility of integrated care provision is caused by characteristics of the legislation, the financing system and other aspects of the institutional context. Here it is argued that these characteristics are relevant but not decisive. Based on empirical evidence from the Dutch case a rival viewpoint is presented, suggesting that it is the commitment of the actors involved, their support, and the way developments are being managed, that make the difference. Following presentation of the evidence, the implications of the findings for integrated care policy are discussed.     

Penetration of ciprofloxacin, norfloxacin and ofloxacin into the aqueous humor using different topical application modes

 · Background: A prospective study was undertaken to determine the transcorneal penetration of three topically applied fluoroquinolones into aqueous humor. · Methods: Cataract patients (n=224) preoperatively received topically applied gyrase inhibitors (0.3% ciprofloxacin, 0.3% norfloxacin, 0.3% ofloxacin) in two different application modes. In application mode I, patients received on the day before operation 3×1 eye drop at 2-h intervals, and on the day of operation 3 drops at 1-h intervals. In application mode II, patients received 9 drops at 15-min intervals on the day of operation only. Just before cataract surgery 50–100 μl aqueous humor was aspirated and stored at –80 °C. The HPLC method was used for measuring the concentration. · Results: The highest concentrations of all tested antibiotics were measured after the mode of application in which one drop was given every 15 min between 06:00 and 08:00 hours before operation. In this mode, ciprofloxacin achieved a mean aqueous level of 379.8±327.8 μg/l (range 33–1388 μg/l), norfloxacin 182.1±118.1 μg/l (range 38–480 μg/l) and ofloxacin 563.9±372.1 μg/l (range 64–1455 μg/l). These mean concentration are all above the MIC₉₀ of gram-negative bacteria like Proteus mirabilis and Escherichia coli. In some cases the concentrations of ciprofloxacin and ofloxacin, but never norfloxacin, reached therapeutic values above the MIC₉₀ of Staphylococcus aureus and Staphylococcus epidermidis · Conclusions: The mean concentration value of 0.3% ciprofloxacin and of 0.3% ofloxacin in the aqueous humor reached the MIC₉₀ values of the frequently occurring gram-positive and gram-negative bacteria. Of the currently available topical fluoroquinolones, ofloxacin achieved the highest aqueous humor concentration. Considering the higher antimicrobial activity of ciprofloxacin, both ciprofloxacin and ofloxacin may be useful ophthalmic agents in antibacterial management, but they are not efficient against Streptococcus pneumoniae and Pseudomonas aeruginosa. Received: 8 September 1997 Revised version received: 19 March 1998 Accepted: 8 April 1998     

Phenotypic variations in a family with retinal dystrophy as result of different mutations in the ABCR gene

AIMS: To describe two phenotypic variations of autosomal recessive retinal dystrophy occurring in a consanguineous family in a pseudodominant pattern, resulting from mutations in the ATP binding cassette transporter (ABCR) gene. METHODS: Patients of this family underwent an extensive ophthalmic evaluation, including fundus photography, fluorescein angiography, and electroretinography (ERG). Genetic analysis comprised sequence analysis of the retina specific ABCR gene. RESULTS: Five patients presented with decreased visual acuity in the second decade, central chorioretinal atrophy associated with a central scotoma, and severely decreased photopic and scotopic ERG responses. This clinical picture, which in our opinion resembles a cone-rod dystrophy (CRD), was associated with compound heterozygosity for IVS30+ 1g -->t and IVS40+5g-->a mutations in the ABCR gene. The four remaining patients presented with night blindness in the first decade because of a retinitis pigmentosa-like (RP-like) dystrophy. In addition to a pale "waxy" optic disc, attenuated retinal vessels and bone spicule deposits, a widespread chorioretinal atrophy was observed. The scotopic ERG was extinguished and the photopic ERG was severely diminished. Genetic analysis revealed a homozygous 5' splice mutation IVS30+1g -->t in the ABCR gene. CONCLUSION: Mutations in the ABCR gene can cause clinical pictures resembling autosomal recessive RP and autosomal recessive CRD.     

Identification of Melissa officinalis Subspecies by DNA Fingerprinting

The random amplified polymorphic DNA analysis (RAPD) is a method to study genetic variability within and between populations and species on the basis of the amplification of anonymous fragments from genomic DNA templates by means of polymerase chain reaction (PCR). We applied RAPD analysis in order to distinguish medicinal plant subspecies at the level of their genomes. In this study we investigated various samples of two MELISSA subspecies and showed that RAPD analysis is a fast and reliable method to distinguish subspecies on the pharmaceutical market that have been previously classified according to the distribution pattern of compounds present in the lemon balm oil.     

Multiple-dose pharmacokinetics, safety, and tolerability of bosentan, an endothelin receptor antagonist, in healthy male volunteers.

The multiple-dose pharmacokinetics, safety, and tolerability of oral bosentan, a selective endothelin receptor antagonist, were investigated in healthy male volunteers. In study A, an ascending-dose, double-blind, placebo-controlled trial, doses of 100, 200, 500, and 1000 mg bosentan or placebo were given once daily for 8 days as tablets (100 and 500 mg dose strength). In study B, a double-blind, placebo-controlled trial, 500 mg tablets of bosentan or placebo tablets were given once daily for 8 days with two additional single intravenous dose administrations of 250 mg bosentan 48 hours before the first and 24 hours after the last oral dose. The drug was very well tolerated. No effects on pulse rate, ECGs, or clinical laboratory tests were observed. Marginal effects on blood pressure were seen in subjects only when standing. The oral bioavailability of bosentan was 43% to 48%, with a small interindividual variability of 20%. Doses above 500 mg did not lead to significant further increases in plasma levels of bosentan. From the first to the last day of the oral treatment phase, plasma concentrations of bosentan decreased by 30% to 40% due to a 2-fold increase in plasma clearance. Absorption and plasma protein binding did not change. The 24-hour urinary excretion of 6 beta-hydroxycortisol was increased in parallel by approximately 1.7-fold, indicating induction of cytochrome P450 3A isozymes. The two metabolites of bosentan reached plasma concentrations well below those of bosentan and will most likely not contribute to the pharmacological activity.