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Johnson Et Al. (johnson + et_al)

Distribution by Scientific Domains
Medical Sciences40%
Life Sciences40%

Selected Abstracts

Toxicity of nonylphenol on the cnidarian Hydra attenuata and environmental risk assessment

ENVIRONMENTAL TOXICOLOGY, Issue 4 2006
S. Pachura-Bouchet
Abstract Alkylphenols and their derivatives, alkylphenol polyethoxylates (APEs), are synthetic chemicals of concern owing to their endocrine properties. Nonylphenol (NP) is a critical APE metabolite because of its recalcitrance to biodegradation, toxicity, and ability to bio-accumulate in aquatic organisms. Studies of NP effects in vertebrates demonstrated estrogenic disrupting properties in fish, birds, reptiles, and mammal cells in which NP displaces the natural estrogen from its receptor. Less is known on its toxicity toward invertebrates. Effects on reproduction have been reported, but toxicity on development has been poorly documented thus far. We investigated NP toxicity on survival and regeneration of the freshwater coelenterate Hydra attenuata. Hydra is known for its regenerative capacity and its sensitivity to chemical pollution. It has been used for over 20 years to screen for teratogenicity of chemicals (Johnson et al. (1982) Teratog Carcinog Mutagen 2:263,276). Our results showed that hydra appeared as one of the most sensitive species to acute and chronic toxicity of NP compared to several freshwater invertebrates. Regeneration was disrupted at NP concentrations lower than those affecting survival. Toxicity thresholds of NP for aquatic vertebrates and invertebrates are also reported and discussed in the context of environmental risk assessment and of water quality objectives recommended for surface waters in industrialized countries. NP levels have decreased during the last decade because of a voluntary agreement of surfactant producers and users. At present, concentrations of NP found in surface waters are far below 1 ,g/L in Europe, but can reach several ,g/L when wastewater treatment plant inefficiency occurs. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 388,394, 2006. [source]

Meconium ileus,it is time to act now!

PEDIATRIC PULMONOLOGY, Issue 10 2010
Matthias Kappler MD
Meconium ileus is a life-threatening presentation of neonates with cystic fibrosis (CF). Notwithstanding, today the long-term prognosis of such patients is comparable to that of CF patients not diagnosed in screening programs and not suffering from this insult,1,3 as confirmed by the article of Johnson et al. in this issue of Pediatric Pulmonology. Good news then for CF patients and CF caretakers, working with the modern interdisciplinary setting of neonatal intensive care, including radiology, anesthesiology, and pediatric surgery experts. State of the art management of life-threatening neonatal ileus during this fragile early phase of life obviously balances all disadvantages associated with neonatal ileus and provides an outcome not different from that in CF patients without meconium ileus, but diagnosed later during early childhood. Pediatr Pulmonol. 2010; 45:949,950. © 2010 Wiley-Liss, Inc. [source]

Editor's remarks: Chemotopic odorant coding in a mammalian olfactory system, Johnson et al., J Comp Neurol 503:1,34,

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2007
Thomas E. Finger Associate Editor
No abstract is available for this article. [source]

Desire for Castration Is Not a Body Integrity Identity Disorder: Comment on Johnson et al. (2007), Brett et al. (2007), and Roberts et al. (2008)

THE JOURNAL OF SEXUAL MEDICINE, Issue 2pt1 2010
Anne A. Lawrence
No abstract is available for this article. [source]

Renewed debate over postnatal oogenesis in the mammalian ovary

BIOESSAYS, Issue 8 2004
Chuck Greenfeld
The central dogma of female reproductive biology has long held that oogenesis ceases prior to birth in mammals. During the first half of the last century, there was much debate about whether this was the case or whether oogenesis continued in the postnatal ovary. A report in 1951 effectively put an end to this debate and laid the foundation for the dogma. A new paper by Johnson et al. (2004)1 resurrects the debate over whether postnatal oogenesis occurs in the mammalian ovary. If confirmed, this would have tremendous impact on issues related to female fertility and reproductive longevity. BioEssays 26:829,832, 2004. © 2004 Wiley Periodicals, Inc. [source]