The effectiveness of early endoscopy for upper gastrointestinal hemorrhage: a community-based analysis

OBJECTIVES: The effectiveness of upper endoscopy in unselected patients with upper gastrointestinal hemorrhage has not been well studied. This study was undertaken to identify factors associated with the performance of early endoscopy (ie, within 1 day of hospitalization) and, after adjusting for these factors, to determine associations between early endoscopy and in-hospital mortality, length of stay, and performance of surgery. METHODS: Subjects in this observational cohort study were 3,801 consecutive admissions with upper gastrointestinal hemorrhage to 30 hospitals in a large metropolitan region. Demographic and clinical data were abstracted from hospital records. A multivariable model based on factors that potentially could relate to the decision to perform endoscopy was developed to determine the propensity (0 to 100%) for early endoscopy in each patient. RESULTS: Early endoscopy was performed in 2,240 patients (59%), and although it was not associated with mortality after adjusting for severity of illness among all patients, it was associated with a higher risk of death for patients in the lowest propensity group. Early endoscopy was associated with a lower likelihood of upper gastrointestinal surgery in all patients and in the two highest propensity groups and with a shorter length of stay in the entire cohort and in all subgroups. CONCLUSIONS: In the absence of specific contraindications, early endoscopy should be considered because of associated reductions in length of stay and surgical intervention. Further studies are needed to identify subgroups in whom the procedure may be associated with adverse effects on survival.     

Laboratory investigation of the mass stability of sampling cassettes from inhalable aerosol samplers

A study was conducted to evaluate the mass stability of the materials used in the construction of samplers with internal cassettes for the gravimetric measurement of inhalable aerosol exposures. The internal cassettes from IOM samplers were studied. Results indicate that the mass stability of filters is uniform, but the mass stability of the cassette material may dramatically affect the results of the measurement. Cassettes constructed from plastic exhibited drastic shifts in mass depending on the environmental conditions of their storage. Under room humidity, the plastic cassettes absorbed 1 to 2 mg of water over several days. When these cassettes were placed in a desiccator, they lost mass consistently but did not approach a stable mass. Studies repeated with cassettes made of stainless steel showed negligible mass variability. Based on this study, the use of stainless steel cassettes is recommended for gravimetric determinations of aerosol exposure, although field blanks may in some cases be used for correction of data from plastic cassettes. This study shows the need to evaluate the mass stability of the cassette material of any sampling device where an internal cassette is weighed together with the filter.     

Surface topography of phytochrome A deduced from specific chemical modification with iodoacetamide

Phytochromes are a photoreversible photochromic light switch for photomorphogenesis in plants. The molecular structure and functional mechanism of phytochromes are not fully understood. On the basis of complete mapping of total tryptic digest of the iodoacetamide-modified oat phytochrome A (phyA), the molecular surface topography of phyA was probed by specific chemical modification of cysteine residues with [14C]iodoacetamide. Under native conditions, only two cysteines (Cys-158 and Cys-311) of eleven half-cystines of the N-terminal chromophore binding domain were modified to a significant extent. In the C-terminal domain, six cysteine residues (Cys-715, Cys-774, Cys-809, Cys-869, Cys-961, Cys-995) were readily accessible to iodoacetamide. Among the reactive cysteine residues, only cysteine-311 displayed reactivity that was dependent on the photochromic form (Pr left arrow over right arrow Pfr) of the photoreceptor. Surprisingly, the modification of Cys-311 in the vicinity of the chromophore attachment site (Cys-321) did not have any detectable effect on spectral properties of phyA. Most of the cysteines of the N-terminal domain (Cys-83, Cys-175, Cys-291, Cys-370, Cys-386, Cys-445, Cys-506) are deeply buried in the core of the chromophore binding domain, as they can be modified only after denaturation of the chromoprotein. In the C-terminal domain, modification of only one cysteine residue (Cys-939) required protein denaturation. Since all 22 half-cystines can be modified with iodoacetamide without reduction of the chromoprotein, it follows that oat phyA does not have any disulfide bonds. We found that Cys-311, Cys-774, Cys-961, and Cys-995 could be easily partially oxidized under the conditions used for phytochrome isolation. The surface topography/conformation of oat phyA and its role in protein-protein recognition in phytochrome-mediated signal transduction are discussed in terms of the relative reactivity of cysteine residues.     

Barley varieties for finishing steers: II. Ruminal characteristics and rate, site, and extent of digestion

Four ruminally and abomasally cannulated steers were used to evaluate the effects of barely variety on rate, site, and extent of digestion of high-concentrate diets. The treatments compared were 1) corn, 2) Gunhilde barley (GUN), Harrington barley (HAR), and 4) Medallion barley (MED). Diets were balanced to be isocaloric and isonitrogenous. Ruminal OM digestion was greater (P = .04) in steers fed corn than in those fed GUN, HAR, and MED (61.9 vs average 53.7%). No differences (P > .10) were seen in ruminal starch digestion (average 92.8%) or in starch flow to the abomasum (average 199 g/d) between diets. Total tract digestion of starch was greater (P = .09) in steers fed barley than in those fed corn (average 98.6 vs 95.7%). Total and nonammonia N presented to the abomasum were greater (P < .05) for steers fed HAR and GUN than for those fed MED and corn. Microbial N flow was lowest (P = .01) in corn-fed steers, highest in steers fed GUN and HAR, and intermediate in steers fed MED. Microbial efficiency was 59% greater (P = .03) in steers fed barley than in steers consuming corn. Ruminal acetate: propionate was lower (P = .002) in steers fed corn and HAR than in those fed GUN and MED. Compared to GUN, HAR, and MED barleys, corn had a lower (P < .03) rate (-.11 vs average -.47) and extent (15 h; 70.3 vs average 98.1%) of in situ starch disappearance. Differences in digestive characteristics found between barley varieties may contribute to differences in animal performance.     

Connexin43 is highly localized to sites of disturbed flow in rat aortic endothelium but connexin37 and connexin40 are more uniformly distributed

Vascular endothelial cells are linked by gap junctions, which facilitate the propagation of electrical and chemical signals along the vessel wall. The aim of this study was to determine the distribution and identity of the gap junction structural proteins (connexins) expressed by endothelial cells in situ. Connexin expression in different regions of the rat aortic endothelium was analyzed with the use of indirect immunofluorescence microscopy and Western blotting. Connexin40 and connexin37 were present in most, if not all, of the thoracic and abdominal aortic endothelia in the form of maculae at cell-cell appositions. In contrast, connexin43 was undetectable in most endothelia but extremely abundant in small numbers of cells localized at the downstream edge of the ostia of branching vessels and at flow dividers, regions that experience turbulent shear stress from disturbed blood flow. To examine the relationship of shear stress and connexin43 expression, localized stress was induced by surgical coarctation of the aorta, which was sufficient to cause striking local upregulation of connexin43 within 8 days. Thus, increases in connexin43 levels are an endothelial response to mechanical stress.     

The association of complete laryngotracheoesophageal cleft with left lung agenesis: pathophysiological clues provided by an experiment of nature

The authors present a patient with complete laryngotracheoesophageal cleft and concurrent left lung agenesis and microgastria. Prenatal ultrasound scan showed polyhydramnios and a hypertrophic right lung. The authors propose that the combination of right lung hypertrophy, polyhydramnios, and microgastria in the absence of a competent laryngeal mechanism may suggest that the preferential path for swallowed amniotic fluid was into the lung, rather than the normal route through the stomach. This case illustrates the prenatal findings suggestive of complete laryngotracheoesophageal cleft and lung agenesis, and suggests a potential causal relationship between shunting of swallowed amniotic fluid into the bronchial tree and prenatal lung hypertrophy and microgastria.     

Pediatric hepatic trauma: does clinical course support intensive care unit stay?

PURPOSE: The objective of this study is to determine if grade of liver injury predicts outcome after blunt hepatic trauma in children and to initiate analysis of current management practices to optimize resource utilization without compromising patient care. METHODS: A retrospective review of 36 children who had blunt hepatic trauma treated at a pediatric trauma center from 1989 to present was performed. Hepatic injuries graded (AAST Organ Injury Scaling) ranged from grade I to IV. Injury Severity Score (ISS), Glasgow Coma Score (GCS), transfusion requirements, liver transaminase levels, associated injuries, intensive care unit (ICU) length of stay, and survival were analyzed. RESULTS: Mean (+/-SEM) age was 6.6+/-0.8 years, mean grade of hepatic injury was 2.4+/-0.2, mean ISS was 17+/-2.6, mean GCS was 13+/-1, and mean transfusion was 15.4 mL/kg of packed red blood cells (PRBC). There were three deaths with a mean ISS of 59+/-9 and a mean GCS of 3+/-0. Death was not associated with a high-grade liver injury, survivors versus nonsurvivors, 2.3+/-0.2 versus 2.7+/-0.3, but was associated with ISS, 13+/-1.4 versus 59+/-9 (P = .005) and GCS, 14+/-1 versus 3+/-0 (P = .005). Only one patient (grade III, ISS = 43) underwent surgery. There were no differences in mean ISS or GCS between grades I to IV patients. The hepatic injury grades of patients requiring transfusion versus no transfusion were significantly different, 3.4+/-0.2 versus 2.2+/-0.2 (P = 0.04). Abused patients had high-grade hepatic injuries and significant laboratory and clinical findings. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly higher in grade III and IV injuries than in grades I and II, 1,157+/-320 versus 333+/-61 (P= .02) and 1,176+/-299 versus 516+/-86 (P= .04), respectively. No children with grade I or II injury had a transfusion requirement or surgical intervention. There were no liver-related complications. CONCLUSIONS: Mortality and morbidity rates in pediatric liver injuries, grades I to IV, correlate with associated injuries not the degree of hepatic damage. ALT, AST, and transfusion requirements are significantly related to degree of liver injury. Low-grade and isolated high-grade liver injuries seldom require transfusion. Blunt liver trauma rarely requires surgical intervention. In retrospect, the need for expensive ICU observation for low-grade and isolated high-grade hepatic injuries is questionably warranted.