Colocolic intussusceptions in children: a pictorial essay and review of the literature.

Colocolic intussusception is a variation of intussusception that is rarely encountered in pediatric patients and as such can prove to be a diagnostic challenge for both the emergency clinician and radiologist. Knowledge of the presentation and imaging findings in these cases can expedite diagnosis and guide the patient to appropriate treatment. The demographics, clinical symptoms, imaging findings, and eventual surgical and pathologic outcomes of 8 children with colocolic intussusception will be presented in this pictorial essay, with a review of the available literature.

Brown fat necrosis with calcifications in the newborn: Risk factors, radiographic findings, and clinical course.

OBJECTIVE: To describe the radiographic appearance of subclinical calcified brown fat necrosis and the associated clinical and laboratory findings. MATERIALS AND METHODS: Picture Archiving and Communications Sytem (PACS) was searched using keywords "soft tissue calcification" and "chest." The clinical record was searched for prior cardiac surgery, bypass, Extracorporeal Membrane Oxygentation (ECMO) and prostaglandin use. Age when calcifications were first detected, location, resolution, and associated laboratory abnormalities were recorded. RESULTS: Nine patients were identified. None had skin lesions. All patients had congenital heart disease and had experienced cardiac/respiratory arrest and/or severe hypotension 1-6 weeks before soft tissue calcifications occurred. Calcifications resolved by 9 weeks to 5 months in 3 patients. The remaining were either deceased or lacked follow-up imaging. Renal ultrasound was performed in all but 1 patient. Nephrocalcinosis was only seen in 1 patient. CONCLUSION: Brown fat necrosis is subclinical, diagnosed on plain film, and likely self-limited. It occurs in term and preterm infants who have undergone significant systemic stress and carries a poor prognosis.

Imaging findings in megacystis-microcolon-intestinal hypoperistalsis syndrome.

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare and frequently lethal form of severe functional intestinal obstruction more commonly found in girls. Imaging features characteristic of this disease include a large dilated bladder, microcolon and intestinal dysmotility. Additional imaging findings may include intestinal malrotation, hydronephrosis and vesicoureteral reflux. It is usually fatal in the first year of life. Because presenting clinical and imaging features can mimic other causes of neonatal bowel obstruction, we compiled examples of this disorder to help the pediatric radiologist recognize imaging findings associated with MMIHS and aid in the development of a long-term management plan and in counseling the family regarding implications of this disorder. We reviewed recent and historical literature relevant to MMIHS and present the imaging and clinical features of four patients with MMIHS treated at our institution as examples of this uncommon disorder.

Retropleural teratoma presenting as an abdominal mass in a 9-month-old boy.

BACKGROUND: Teratomas are rare tumors that present most commonly in the anterior mediastinum and retroperitoneum. To date, the retropleural primary site has not been reported. CASE PRESENTATION: A 9-month-old boy presented with a large, painless, right-sided abdominal mass. Laboratory values, including tumor markers α-fetoprotein and ß-human chorionic gonadotropin, were within normal limits. Diagnostic imaging, including abdominal ultrasound, computed tomographic scan, and magnetic resonance imaging, suggested a large retroperitoneal mass consistent with a teratoma. Because the mass was thought to be arising from the retroperitoneum, an abdominal approach was chosen. After adequate exposure, it became clear that the tumor was arising from above the diaphragm. The diaphragm was incised, and the pleural cavity was entered. The tumor was found in the retropleural space where it was dissected away from the inferior vena cava, aorta, and chest wall. The patient recovered without complications. RESULTS: Histologic examination revealed a mature cystic teratoma with no malignant features. The patient has been disease-free at 7-year follow-up, based upon both clinical examination and diagnostic imaging. CONCLUSION: This is the first case report of a teratoma arising from the retropleural space. Preoperative imaging may be inaccurate for guiding surgical planning because the diaphragm may not be clearly visualized with current diagnostic techniques. Surgeons should be cautious regarding the location of tumors that arise near the diaphragm and should plan surgical resection carefully.

Transient receptor potential melastatin 8 channel involvement in the regulation of vascular tone.

The transient receptor potential melastatin 8 (TRPM8) channel has been characterized as a cold and menthol receptor expressed in a subpopulation of sensory neurons but was recently identified in other tissues, including the respiratory tract, urinary system, and vasculature. Thus TRPM8 may play multiple functional roles, likely to be in a tissue- and activation state-dependent manner. We examined the TRPM8 channel presence in large arteries from rats and the functional consequences of their activation. We also aimed to examine whether these channels contribute to control of conscious human skin blood flow. TRPM8 mRNA and protein were detected in rat tail, femoral and mesenteric arteries, and thoracic aorta. This was confirmed in single isolated vascular myocytes by immunocytochemistry. Isometric contraction studies on endothelium-denuded relaxed rat vessels found small contractions on application of the TRPM8-specific agonist menthol (300 microM). However, both menthol and another agonist icilin (50 microM) caused relaxation of vessels precontracted with KCl (60 mM) or the alpha-adrenoceptor agonist phenylephrine (2 microM) and a reduction in sympathetic nerve-mediated contraction. These effects were antagonized by bromoenol lactone treatment, suggesting the involvement of Ca(2+)-independent phospholipase A(2) activation in TRPM8-mediated vasodilatation. In thoracic aorta with intact endothelium, menthol-induced inhibition of KCl-induced contraction was enhanced. This was unaltered by preincubation with either N(omega)-nitro-l-arginine methyl ester (l-NAME; 100 nM), a nitric oxide synthase inhibitor, or the ACh receptor antagonist atropine (1 microM). Application of menthol (3% solution, topical application) to skin caused increased blood flow in conscious humans, as measured by laser Doppler fluximetry. Vasodilatation was markedly reduced or abolished by prior application of l-NAME (passive application, 10 mM) or atropine (iontophoretic application, 100 nM, 30 s at 70 microA). We conclude that TRPM8 channels are present in rat artery vascular smooth muscle and on activation cause vasoconstriction or vasodilatation, dependent on previous vasomotor tone. TRPM8 channels may also contribute to human cutaneous vasculature control, likely with the involvement of additional neuronal mechanisms.

Modulation of contractile function through neuropeptide Y receptors during development of cardiomyocyte hypertrophy.

Severity of left ventricular hypertrophy (LVH) correlates with elevated plasma levels of neuropeptide Y (NPY) in hypertension. NPY elicits positive and negative contractile effects in cardiomyocytes through Y(1) and Y(2) receptors, respectively. This study tested the hypothesis that NPY receptor-mediated contraction is altered during progression of LVH. Ventricular cardiomyocytes were isolated from spontaneously hypertensive rats (SHRs) pre-LVH (12 weeks), during development (16 weeks), and at established LVH (20 weeks) and age-matched normotensive Wistar Kyoto (WKY) rats. Electrically stimulated (60 V, 0.5 Hz) cell shortening was measured using edge detection and receptor expression determined at mRNA and protein level. The NPY and Y(1) receptor-selective agonist, Leu(31)Pro(34)NPY, stimulated increases in contractile amplitude, which were abolished by the Y(1) receptor-selective antagonist, BIBP3226 [R-N(2)-(diphenyl-acetyl)-N-(4-hydroxyphenyl)methyl-argininamide)], confirming Y(1) receptor involvement. Potencies of both agonists were enhanced in SHR cardiomyocytes at 20 weeks (2300- and 380-fold versus controls). Maximal responses were not attenuated. BIBP3226 unmasked a negative contraction effect of NPY, elicited over the concentration range (10(-12) to 3 x 10(-9) M) in which NPY and PYY(3-36) attenuated the positive contraction effects of isoproterenol, the potencies of which were increased in cardiomyocytes from SHRs at 20 weeks (175- and 145-fold versus controls); maximal responses were not altered. Expression of NPY-Y(1) and NPY-Y(2) receptor mRNAs was decreased (55 and 69%) in left ventricular cardiomyocytes from 20-week-old SHRs versus age-matched WKY rats; parallel decreases (32 and 80%) were observed at protein level. Enhancement of NPY potency, producing (opposing) contractile effects on cardiomyocytes together with unchanged maximal response despite reduced receptor number, enables NPY to contribute to regulating cardiac performance during compensatory LVH.