The effect of bacterially produced vitamin B12 analogues (cobamides) on the in vitro absorption of cyanocabalamin.

An incubation system containing rat jejunoileum was used to determine whether analogues of cyanocabalamin (CNCbl) inhibited the in vitro absorption of CNCbl. The naturally occurring analogues "pseudo B12," "factor A," and the nonnaturally occurring analogue desdemethyl B12, were produced by guided biosynthesis with Propionibacterium arabinosum. Factor B was produced by acid cleavage of cyanocabalamin. Inhibition of Co57-CNBbl uptake was demonstrated for cold CNCbl and for desdemethyl B12, although statistical significance was achieved only for cold CNCbl at 40X and 100X the molar quantity of the radiolabeled CNCbl. However, a trend towards progressive inhibition of specific CNCbl binding was shown as increasing concentrations of CNCbl or desdemethyl B12 were used. No inhibition of specific CNCbl binding could be demonstrated for any of the naturally occurring cobamides tested.     

Magnetic resonance imaging compared with echocardiography in the evaluation of pulmonary artery abnormalities in children with tetralogy of Fallot following palliative and corrective surgery

Background. Abnormalities of the pulmonary arteries following palliative or corrective surgery for tetralogy of Fallot (TOF) are common. Our purpose was to compare the usefulness of magnetic resonance imaging (MRI) and echocardiography in the post- operative evaluation of the pulmonary arteries in children with TOF. Objective. Our hypothesis was that MRI is more sensitive than echocardiography in the detection of branch pulmonary artery abnormalities in children with TOF. Materials and methods. Pulmonary artery MRI and echocardiography were performed in 20 children following palliative and/or corrective surgery for TOF. MRI and echocardiography were compared in their ability to detect abnormalities of the pulmonary arteries. Angiographic or surgical correlation was available in 15 children. A perfusion scan for confirmation of pulmonary artery patency was available in one additional child. Results. Abnormalities of the branch pulmonary arteries identified by MRI included: absence or occlusion (2), focal stenosis (15), hypoplasia (2), aneurysm (1), and non-confluence (1). Echocardiography could not adequately visualize the right and left branch pulmonary arteries in eight and ten children, respectively. Echocardiography missed stenosis in 13 branch pulmonary arteries, patency of hypoplastic pulmonary arteries in two children, non-confluence of the pulmonary arteries in one child, and a left pulmonary artery aneurysm in one child. Abnormalities identified by MRI were confirmed in 16 children by angiography, surgery or perfusion scan. Conclusion. MRI is more sensitive than echocardiography for the evaluation of branch pulmonary artery abnormalities in children following surgery for TOF. Received: 13 January 1997 Accepted: 31 July 1997     

The influence of reported paternal attitudes on the decision to breast-feed

Objective: To identify factors that influence a woman's decision to breast-feed.
Methodology: Five hundred and fifty-six women were recruited from the maternity wards of two Perth hospitals. Data were collected from a self-administered questionnaire completed by participants prior to discharge. Logistic regression analysis was used to determine factors influencing the initiation of breast-feeding.
Results: At discharge from hospital 83.8% of women were breast-feeding, including 6% who were giving complementary formula feeds. After controlling for potentially confounding demographic and biomedical factors, the father's reported preference for breast-feeding was found to be the most important factor influencing a woman's decision to breast-feed (OR 10.18).
Conclusion: Fathers participate in and influence the choice of infant feeding method and should be included in breast-feeding discussions.     

Margin of safety for discharge after apnea in preterm infants

OBJECTIVE: Most neonatologists include an apnea-free period in the criteria for the discharge of preterm infants. However, the length of time one should wait after the cessation of apnea before sending an infant home without a monitor is debated. We undertook this study in an attempt to define a minimal and safe observation period between the time of the last apnea episode and discharge. METHODS: We reasoned that in infants with idiopathic apnea of prematurity, the intervals between days on which apnea occurs gradually increase until some point at which clinically significant apnea ceases. Therefore, knowledge about the intervals between days on which apnea occurred just before the last apnea would provide a reasonable estimate of the minimal safe observation interval between the last apnea and discharge. We reviewed the charts of 266 infants born in 1993 and 1994 at 相似文献   

Immediate-early gene expression in cerebral cortex following exposure to chronic-intermittent hypoxia

Chronic-intermittent hypoxia (CIH) was postulated to evoke c-fos expression in cortical regions that modulate sympathetic discharge. Animals exposed to CIH for 30 days exhibited c-fos labeling in medial prefrontal, cingulate, retrosplenial, and insular cortices. Our findings strongly suggest activation of cortical circuits that adaptively regulate sympathetic and cardiovascular activities.     

UNUSUAL CEREBELLAR GANGLIOGLIOMA WITH MARKED CYTOLOGIC ATYPIA

Neuronal differentiation is well documented in cerebellar primitive neuroectodermal tumors but is uncommon in other cerebellar neoplasms. Although rare, gangliogliomas and gangliocytomas have been previously described in the cerebellum. We report a cerebellar ganglioglioma in a 14-year-old boy, which revealed bizzare markedly pleomorphic cells with extremely pronounced nuclear atypia but less than one mitosis per 50 high-power fields and no necrosis. The tumor showed glial as well as neuronal differentiation, with abundant bi- and multinucleated ganglion cells. There were abundant Rosenthal fibers, eosinophilic granular bodies, focal calcification, and perivascular lymphocytic infiltrates. There has been no evidence of tumor recurrence or neurological deterioration 21 years after surgery, although the marked nuclear atypia led to an initial diagnosis of an anaplastic glioma. We stress the need for careful evaluation of cerebellar gliomas in children that show only nuclear atypia or endothelial hyperplasia in the absence of other features of malignancy.