The photostability of the fluoroquinolones ciprofloxacin (CPX), ofloxacin (OFX), and fleroxacin (FLX) toward ultraviolet irradiation (UVA) and room light was investigated in dilute aqueous solutions. A series of photoproducts was observed by high-performance liquid chromatography (HPLC) for all three drugs. As little as 1 h of exposure to room light was enough for the formation of detectable amounts of CPX photoproducts. The major CPX photoproduct was characterized as a dimer by liquid secondary ion mass spectrometry, but its structure was not determined. Since irradiation of CPX results (as cited in ref/11) in a loss of antibacterial activity and since all substances, parent drugs as well as their photoproducts, are potential candidates for undesired drug effects, quinolone drugs should be strictly protected from all light during storage and administration.

Anti-Infective Agents↗

PubMed1994

Kinetics and differentiation of somite cells forming the vertebral column: studies on human and chick embryos.

We have studied the kinetics of somite cells with an antibody against proliferating cell nuclear antigen (PCNA/cyclin) in human and chick embryos, and with the BrdU anti-BrdU method in chick embryos, to investigate whether the metameric pattern of the developing vertebral column can be explained by different proliferation rates. Furthermore we applied antibodies against differentiation markers of chondrogenic and myogenic cells of the somites in order to study the correlation between proliferation and differentiation. There are no principal differences in the proliferation pattern of the vertebral column between human and chick embryos. In all stages examined, the cell density is higher in the caudal sclerotome halves than in the cranial halves. Laterally, the caudal sclerotome halves, which give rise to the neural arches, are characterized by a higher proliferative activity than the cranial halves. Although there is a high variability, the labelling indices show significant differences between the two halves with both proliferation markers. With the onset of chondrogenic differentiation, only the perichondrial cells retain a high proliferation rate. During fetal development, the neural arches and their processes grow appositionally. Even at the earliest stages, there is practically no immunostaining for PCNA or BrdU in the desmin-positive myotome cells of human and chick embryos. Axially, a higher proliferation rate is found in the condensed mesenchyme of the anlagen of the intervertebral discs than in the anlagen of the vertebral bodies. During fetal development, cells at the borders between vertebral bodies and intervertebral discs proliferate, indicating appositional growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Electron emission and image-charge acceleration for the impact of very highly charged ions on clean gold.

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Journal Article↗

PubMed1994

Modelling of vascular growth processes: a stochastic biophysical approach to embryonic angiogenesis.

In a computer simulation, growth of a capillary network is driven by a stochastic process on a planar hexagonal grid. Starting at a point source, the probabilities for the formation of new capillary elements depend on local biophysical knowledge. This knowledge is mainly derived from the flow theorem of Hagen-Poiseuille and the diameter exponent delta. The hexagonal grid is visualized as being supported by a cylinder or a sphere. An arterial tree results from the adaptive diameter augmentation, and is considered to have limited fractal properties. The dimension of its border, and the time course of growth and of blood pressure are compared with biological data from the chorioallantoic membrane (CAM) of incubated chicken eggs. The model is discussed in view of mechanosensitivity and cell-matrix interactions of endothelial cells, and CAM haemodynamics.

Allantois↗

PubMed1994

[Adverse health effects in children caused by passive smoking].

The harmful effects of passive smoking (PSE) start early in intrauterine life and comprise direct toxic effects of components of tobaccos smoke on the fetus as well as indirect effects by impeding the normal nutrition of the growing child over effects on the placenta. Consequences are diminished birthweight, and increased perinatal mortality. The sudden infant death syndrome is associated with PSE as are increased incidence of respiratory illnesses in early childhood. Increased bronchial responsiveness, increased asthma prevalence, delayed lung growth and increased incidence of chronic respiratory symptoms later in childhood may well put these children at increased risk for developing chronic obstructive pulmonary disease in their later life.

Adolescent↗

PubMed1994

[Extrapulmonary tuberculosis in childhood. Case reports from a pediatric specialty hospital].

The immigration of people from countries with high incidence of tuberculosis has led to an increased number of cases of tuberculosis in Austria. The number of cases of extrapulmonary tuberculosis has increased too. The variability of the clinical presentation of extrapulmonary tuberculosis which can affect almost every organ system makes it essential to include it in the differential diagnosis of any infectious disease. Early identification and rapid onset of therapy are most important for recovering without complications and avoidance of longterm sequelae. 9 cases of extrapulmonary tuberculosis in the Gottfried von Preyer Children's hospital from 1989 to 1992 show the different clinical features of this disease. 3 cases of tuberculous lymphadenitis, 1 case of tuberculosis of the adenoids, 1 case of tuberclulous pleurits, 3 cases of gastrointestinal tuberculosis and 1 case of a tuberculous meningitis and osteomyelitis are described. All 9 children recovered with antituberculous treatment without complications or sequelae.

Adolescent↗

PubMed1994