Nitric oxide (NO) is a cellular mediator and regulator of multiple biologic functions. NO released by alveolar macrophages (AM) is suggested to play a role in mediating pulmonary injury. In murine and rat macrophages, the expression of inducible NO synthase (iNOS) and the release of NO are well established. However, the existence of such a pathway in other species remains controversial. In this study, we examined NO production and iNOS expression by AM from rats and hamsters, two laboratory animal species that are characterized by their disparate pulmonary responses to various inhaled irritants/toxicants. AM were treated with lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), or tumor necrosis factor-alpha (TNF-alpha) in vitro, and nitrite, the stable oxidation product of NO, was assayed by the Griess reaction. Rat AM produced NO in a dose- and time-dependent manner upon stimulation with LPS and/or IFN-gamma, but not with TNF-alpha. Surprisingly, hamster AM did not release detectable levels of NO after the same treatment. Although iNOS expression was demonstrated in rat AM by immunocytochemical and Western blot analyses, no induction of iNOS expression could be found in hamster AM. Using reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, we found that rat and hamster AM could be induced to express iNOS mRNA after treatment with LPS and IFN-gamma. The results presented here indicate that hamster AM, in contrast to rat AM, lack the ability to express iNOS protein and to generate NO in response to LPS, IFN-gamma, or TNF-alpha in vitro. In conclusion, our data suggest striking differences in iNOS regulation and NO production by AM from rats and hamsters, two rodent species that are commonly used in biomedical research and well-known for their disparate responses to pulmonary irritants/toxicants.
Laparoscopic resection of congenital choledochal cyst and choledochojejunostomy in children is feasible. We feel that there is a considerable learning curve with the technique. Future studies will have to prove the feasibility of laparoscopic Roux-en-Y bowel anastomosis without the need for bowel exteriorization.
Numerous investigators have shown that video-assisted thoracoscopic surgery (VATS) can be safely used for specific conditions of newborns, infants, and children. The technique has been postulated to be associated with a lower morbidity, shorter hospital stay, lower costs, and clinical results similar to those achieved by open surgery. The present article reviews the state of the art of VATS for thoracic conditions in children. Most authors focus on the feasibility of single procedures, and only a small number of reports deals with the feasibility in series with multiple types of procedures and larger numbers of patients. Therefore, systematic research on the advantages and limits of VATS in children remains mandatory.
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