Nitric oxide synthase is absent in only a subset of cases of pyloric stenosis.
OBJECTIVE
The aim of this study was to study nitric oxide synthase (NOS) immunohistochemistry in the pyloric muscle and establish the role of nitric oxide in pyloric stenosis.


METHODS
Pyloric muscle biopsy specimens were obtained from 20 patients with pyloric stenosis during pyloromyotomy. Ten control specimens without pyloric disease were obtained from autopsy performed less than 4 hours after death on age-matched babies who died of other causes. Tissues were fixed in 4% paraformaldehyde immediately. A monoclonal antibody against the neuronal form of NOS (bNOS) was used for immunohistochemistry.


RESULTS
Immunohistochemistry showed activity of bNOS in the control specimens and some pyloric stenosis specimens. This shows that NOS is present in the pylorus in normal cases as well as in a few cases of pyloric stenosis.


CONCLUSIONS
NOS deficiency leading to lack of locally available nitric oxide causes a failure of smooth muscle relaxation. This may account for the cause of pyloric stenosis in infants. However, this study shows that this is true probably only in a subset of cases. The etiology of pyloric stenosis may still be multifactorial. Further investigations are required regarding the etiology of pyloric stenosis. J Pediatr Surg 36:616-619.
Subramaniam
R
R
Department of Paediatric Surgery and Pathology, Booth Hall Children's Hospital, Blackley, Manchester, England.
Doig
C M
CM
Moore
L
L
D001707:Biopsy, Needle; D002675:Child, Preschool; D046508:Culture Techniques; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009126:Muscle Relaxation / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000032:analysis*; D011446:Prospective Studies; D011707:Pyloric Stenosis / Q000201:enzymology* / Q000473:pathology*; D012016:Reference Values; D012680:Sensitivity and Specificity
D019001:Nitric Oxide Synthase