The apical surface of mouse urothelium is covered by two-dimensional crystals (plaques) of uroplakin (UP) particles. To study uroplakin function, we ablated the mouse UPII gene. A comparison of the phenotypes of UPII- and UPIII-deficient mice yielded new insights into the mechanism of plaque formation and some fundamental features of urothelial differentiation. Although UPIII knockout yielded small plaques, UPII knockout abolished plaque formation, indicating that both uroplakin heterodimers (UPIa/II and UPIb/III or IIIb) are required for plaque assembly. Both knockouts had elevated UPIb gene expression, suggesting that this is a general response to defective plaque assembly. Both knockouts also had small superficial cells, suggesting that continued fusion of uroplakin-delivering vesicles with the apical surface may contribute to umbrella cell enlargement. Both knockouts experienced vesicoureteral reflux, hydronephrosis, renal dysfunction, and, in the offspring of some breeding pairs, renal failure and neonatal death. These results highlight the functional importance of uroplakins and establish uroplakin defects as a possible cause of major urinary tract anomalies and death.

Thin-section, high-resolution (1.0/1.5 mm thick slices), low-dose chest CT scans were performed in 55 infants and children. The studies were carried out with 1- and 2-s scan (data acquisition) times using a high-resolution (bone) algorithm. Although there was some motion artifact, the studies provided valuable information for evaluating diffuse parenchymal lung disease. The thin slices provided finer detail and more diagnostic information than images representing thicker sections. Most studies were performed using between 40 and 80 mAs. It is estimated that the patients' radiation exposure was 20% that of conventional high-resolution CT (HRCT) and 57% that of routine chest CT. Diagnostic HRCT scans can be obtained in infants and young children without the need for suspended respiration or specialized ultrafast CT scanners.

We evaluated the use of sonography in monitoring the efficacy of suppressive therapy with a gonadotropin releasing hormone analogue in girls being treated for isosexual precocious puberty. Ten girls 5 to 9 years of age underwent serial sonography and hormonal stimulation tests on the same day. Sonographic trends of decreasing ovarian volume and uterine length indicated early suppression even when absolute values were above threshold. Isosexual precocious puberty in girls can be defined as the premature development of secondary sexual characteristics with associated ovarian and uterine maturation that is inappropriate Changes in ovarian volume were the most sensitive predictor of pituitary-gonadal suppression. Sonography is a sensitive and accurate method of monitoring medical therapy; ovarian volume and analysis of interval change are the most sensitive barometers of change. KEY WORDS: Ultrasonography in infants and children; Pelvic organs; Ovary; Uterus; Precocious puberty. for the patient's age. Clinically, the diagnosis is considered in girls who develop secondary sexual characteristics before 8 years of age or menses before 9 years of age. 1 Approximately 80% of these cases are due to idiopathic activation of the hypothalamicpituitary-~nadal axis without an underlying anatomic cause. In evaluating the patient at the time of initial diagnosis, sonography is capable of describing the initial morphologic changes that have taken place in the uterus and ovaries, and can identify the rare instances of primary gonadal or adrenal neoplasm.4The key physiologic factor that makes sonography useful for monitoring these patients is that the maturational morphologic changes of the uterus and ovaries associated with hormonal stimulation are reversible. When endocrinologic neuraxis suppression is achieved, these organs revert to an infantile (nonstimulated) appearance. 5 ' 6 This regression of sonographic morphologic features normally is observed in women at menopause.Tanner staging measures maturation by means of

Combined cine gradient-recalled echo MRI and MR angiography is a reliable method for imaging pulmonary vascular supply in patients with these disorders. Additional prospective studies comparing MRI and conventional angiography may determine whether routine preoperative conventional angiography is required.

No abstract

In patients with Tetralogy of Fallot, collateral supply to the pulmonary-artery from systemic arterial sources is fequently encountered. However, collateral blood flow arising from the cerebral circulation has, to our knowledge, not been reported in this condition. We describe a patient with Tetralogy of Fallot in whom the left pulmonary artery filled directly via retrograde flow from the left carotid artery. Review of the literature in search of a similar case was unrevealing. A theoretical embryologic basis for this anomaly is discussed. Case reportSV was the 2.7 kg product of a full term gestation. In the newborn period a harsh systolic murmur along the left sternal border and minimal cyanosis were noted. ECG demonstrated right ventricular dominance. The chest roentgenogram showed a right aortic arch and slightly diminished but symmetrical pulmonary vascular markings. An echocardiogram revealed infundibular and valvar pulmonic stenosis with a malalignment ventricular septal defect (VSD). Based on these data, a diagnosis of Tetralogy of Fallot was made.The patient had only minimal cyanosis, and was neurologically intact. At four months of age, a faint continuous murmur became audible at the base. Cardiac catheterization at I6 months revealed infundibular and valvar pulmonic stenosis with a malalignment VSD and overriding aorta. The pulmonary arteries were in continuity and both right and left branch pulmonary arteries filled through the right ventricular injection. The ductus arteriosus was not patent. This study and an arch aortogram done prior to surgical correction at 3 years of age demonstrated that the right aortic arch gave rise separately to four branches: the right internal and external carotids, followed by the right subclavian artery and an aberrant left subclavian as the last branch of the arch. The left carotid did not arise from the aorta but functioned as a connection between the circle of Willis and the left pulmonary artery. Specifically there was retrograde filling of the left carotid artery through the cerebral circulation and through multiple redundant cervical collaterals; the left carotid artery then joined the left pulmonary artery in the region of the ductus arteriosus (Fig. 1).The complete repair consisted of a pulmonary valvulotomy and infundibular widening With a short outflow patch and repair of the VSD. The anomalous carotid artery (4 mm in diameter) was surgically identified, ligated and divided at its entry into the pulmonary artery. The postoperative course was completely uneventful. She was discharged on no medications on the seventh postoperative day. Neurologically the child remains intact. DiscussionThe most common source of systemic collateralization in patients with Tetralogy of Fallot is aberrant vessels arising from the descending aorta. Less frequent sources of flow to a pulmonary artery which have been reported include ductal (6th arch) and hemitruncus, i.e., origin of a pulmonary artery from the ascending aorta (aortic sac) [1].Anomalies of the aortic arch are common in...

Although most often recognized in neonates and young children, congenital cystic adenomatoid malformation of the lung (CCAM) occasionally appears in later years. Three patients, aged 35, 24, and 7 years, are reported. Chest radiographs in each case suggested a localized patchy density, a cystic mass, or a multicystic mass, but computed tomography (CT) best demonstrated the cystic and solid components while ruling out bronchiectasis or major bronchial obstruction. Bronchography contributed no further diagnostic information compared with CT. Each patient underwent lobectomy. Histologically, the characteristic overgrowth of bronchiolar elements replacing normal parenchymal architecture was accompanied by some superimposed inflammatory change. Each patient had a history of pneumonia, and in such patients, characteristic radiographic features should suggest the possibility of late presentation of CCAM.

CT performed to diagnose appendicitis can be limited to the region below the RLP.