Cricoid split for subglottic stenosis in infancy

Historically, tracheostomy has been used for infants with airway obstruction caused by congenital or acquired subglottic stenosis. Postoperative morbidity and mortality with this provisional operation led Cotton, in 1980, to substitute anterior cricoid split as the primary definitive procedure. Within the past three years, anterior cricoid split has been performed in 4 infants, aged 3 to 9 months, with acquired (3 patients) or congenital (1 patient) subglottic stenosis requiring ventilation through an endotracheal tube. Following cricoid split, the trachea is stented for 12 to 14 days by a nasotracheal tube, with extubation and rigid bronchoscopy in the operating room with the patient under anesthesia to confirm healing and patency. During an 18- to 24-month follow-up in these 4 patients, morbidity has been minimal, patency has persisted, and stridor has not recurred. Accordingly, a conclusive operation, cricoid split, rather than a temporizing tracheostomy may be employed for certain obstructive tracheal lesions early in life.     

Superantigen responses and co-stimulation: CD28 and CTLA-4 have opposing effects on T cell expansion in vitro and in vivo

Co-stimulation via the CD28/CTLA-4 system appears critical forT cell proliferation to peptide antigens presented in associationwith MHC. In this study, we examine the roles of CD28 and CTLA-4in the response of murine T cells to the superantigen staphylococcalenterotoxin B (SEB). In vitro, antibodies against B7-1/B7-2or Fab fragments of anti-CD28 antibodies significantly inhibitthe response of splenocytes to SEB. Conversely, Fab fragmentsof anti-CTLA-4 antibodies augment the proliferative response.Further, addition of blocking antibodies directed against B7-1/B7-2augment proliferation co-stimulated by intact anti-CD28 antibodies.These data support the hypothesis that CD28 and CTLA-4 exertopposing effects upon early T cell activation. In vivo, Intactanti-CD28 antibodies and non-stimulatory Fab fragments of anti-CD28appear to have similar inhibitory effects upon the expansionof V_ß8⁺ T cells. In contrast, both intact and Fabfragments of anti-CTLA-4 appear to amplify this expansion. Weconclude that the SEB response is significantly augmented byCD28-derived signaling and this in turn may be attenuated bysignals through CTLA-4.     

Survival and developmental disability in infants with birth weights of 501 to 800 grams, born between 1979 and 1994

OBJECTIVE: Because the survival rate has increased for extremely low birth weight neonates, many have raised the concern that the rate of developmental disability among survivors will also increase. To address this concern, we analyzed changes over time in survival and major neurosensory impairment in a sample of extremely low birth weight infants born between July 1, 1979, and June 30, 1994. METHODS: The study sample included 513 infants with birth weights of 501 to 800 g who were cared for in either of the two neonatal intensive care units that serve a 17-county region in northwest North Carolina and who were born to mothers residing in that region. At 1 year of age (corrected for gestation), survivors were examined by a pediatrician and were tested using the Bayley Scales of Infant Development. Major neurosensory impairment was defined as cerebral palsy, a Bayley Mental Developmental Index <68, or blindness. A total of 209/216 (97%) of survivors were examined at 1 year of age. Epoch of birth was defined as follows: epoch 1, July 1, 1979 to June 30, 1984; epoch 2, July 1, 1984 to June 30, 1989; and epoch 3, July 1, 1989 to June 30, 1994. RESULTS: Survival rates for epochs 1, 2, and 3 were, respectively, 24/120 (20%), 63/175 (36%), and 129/218 (59%). In contrast, the proportions with a major neurosensory impairment did not increase over time; rates for successive epochs were 6/24 (25%), 17/61 (28%), and 26/124 (21%). Rates of cerebral palsy were 3/24 (13%), 12/61 (20%), and 9/124 (7%); rates of delayed mental development were 4/24 (17%), 12/61 (20%), and 17/124 (14%); and rates of blindness were 2/24 (8%), 0/62, and 5/124 (4%), respectively. CONCLUSIONS: This analysis suggests that the increasing survival of extremely low birth weight neonates since the late 1970s has not resulted in an increased rate of major developmental problems identifiable at 1 year of age.     

Aberrant crypt focus promotion and glucose intolerance: correlation in the rat across diets differing in fat, n-3 fatty acids and energy

McKeown-Eyssen (Cancer Epidemiol. Biomarkers Prevent., 3, 687-695, 1994) and Giovannucci (Cancer Causes Control, 6, 164-179, 1995), noting the striking similarity in lifestyle risk factors for colorectal cancer and insulin resistance, proposed that the hyperinsulinemia, glycemia and hypertriglyceridemia associated with insulin resistance promotes colon cancer. To compare the effect of diet on colon cancer promotion and insulin resistance in the F344 rat, we assessed the effect of fat, n-3 fatty acids and energy in pairwise comparisons on average size of aberrant crypt foci (ACF) and on glucose intolerance in the same animals in a single experiment. Diets high in fat and energy increased and diets with increased n-3 fatty acids and calorie restriction decreased both ACF growth and glucose intolerance compared with control diets. The measures of promotion of colon cancer and insulin resistance were strongly correlated (n = 98, r = 0.67, P < 0.001). In addition, both were highly correlated with daily energy intake (r = 0.62 and 0.66) and were also correlated with basal (post-prandial) insulin, glucose and triglycerides (r = 0.31-0.53, P < 0.01). We concluded that ACF growth and glucose intolerance are correlated for a wide range of diets and that increased circulating energy (glucose and triglycerides) may lead to both colon cancer promotion and insulin resistance.