TTF-1 and HNF-3beta in the developing tracheoesophageal fistula: further evidence for the respiratory origin of the distal esophagus'.

PURPOSE: Using an established rat model of esophageal atresia with tracheoesophageal fistula (EA-TEF), the authors have studied the organogenesis of this congenital anomaly. The authors previously have proposed that the "distal esophagus" actually is of respiratory lineage. In this report this hypothesis is tested by examining the expression of two foregut patterning transcription factors, thyroid transcription factor-1 (TTF-1) and hepatocyte nuclear factor-3beta (HNF-3beta), within the developing TEF. METHODS: Pregnant Sprague-Dawley rats were injected with 2.2 mg/kg of Adriamycin intraperitoneally on days 6 to 9 of gestation. Using microdissection, the trachea, blind-ending esophagus, TEF, and stomach were isolated from embryos of various gestional ages. Immunohistochemistry was performed using polyclonal antibodies to TTF-1 and HNF-3beta. RESULTS: TTF-1 is a homeodomain protein that previously has been shown to be expressed in the lung and trachea but not in the gastrointestinal tract, and which, when deleted in a developing lung, results in a mouse with no peripheral lung parenchyma. TTF-1 was expressed strongly in the lung, fistula, and distal esophagus, but not in the proximal esophagus. HNF-3beta is a forkhead transcription factor important in foregut patterning that binds and activates the TTF-1 promotor sequence. HNF-3beta was expressed globally in the fistula and lung as well as the esophagus. CONCLUSIONS: The expression of the lung-specific transcription factor TTF-1 within the TEF strongly implies that the "distal esophagus" is a respiratory-derived structure and thus supports our theory of TEF organogenesis. The conservation of HNF-3beta expression both in the TEF as well as the normal developing trachea and esophagus suggests that global foregut patterning is intact in the formation of this anomaly, and the defect lies at the level of the respiratory versus gastrointestinal commitment.

The ontogeny of TGF-beta1, -beta2, -beta3, and TGF-beta receptor-II expression in the pancreas: implications for regulation of growth and differentiation.

BACKGROUND/PURPOSE: The transforming growth factor-beta (TGF-beta) cytokines are important regulators of growth and differentiation in multiple mammalian organ systems. Recent studies suggest that they may play a significant role in the regulation of pancreatic organogenesis. The authors proposed to examine the ontogeny of expression of the TGF-beta cytokine isoforms (TGF-beta1, beta2, and beta3), as well as that of the type II TGF-beta receptor (TbetaRII), in the pancreas. We hypothesized that their patterns of expression might help to clarify the manner in which they influence the development of this organ. METHODS: Embryos from pregnant CD-1 mice were harvested on gestational days 12.5, 15.5, and 18.5. Microdissection was performed on the embryos to isolate their pancreases. The pancreases were fixed, frozen embedded, and sectioned with a cryostat. Immunohistochemistrywas performed using polyclonal antibodies to TGF-beta1, beta2, and beta3, and TbetaRII. RESULTS: The patterns of expression of TGF-beta1, beta2, and beta3 were similar throughout gestation. They were all present, though weakly, early in the development of the pancreas, in the E12.5 epithelial cells. Their expression persisted and became localized to the acinar cells later in gestation. TbetaRII staining was present in both the E12.5 epithelial cells and the surrounding mesenchyme. As the pancreas developed, TbetaRII became strongly expressed in the ductal epithelial cells with only minimal staining in the acinar and endocrine cells. CONCLUSIONS: TGF-betas may play a role in regulating pancreatic organogenesis. Our data suggest that they may be required for the normal development of acini. As in other cell systems, TGF-beta1 may act as a suppressor of pancreatic cellular growth and differentiation. The localization of TbetaRII to the mature ductal epithelium may indicate a need for ongoing regulation of growth and differentiation in the pancreatic ducts beyond the fetal period.

Epithelio-mesenchymal interactions in the developing mouse pancreas: morphogenesis of the adult architecture.

BACKGROUND/PURPOSE: The mammalian pancreas is thought to develop through a complex interaction between the budding epithelium and the surrounding mesenchyme. The exact nature of this interaction is unclear. Most of what is known to date of these interactions comes from a series of organ culture experiments done in the late 1960s. Nevertheless, these important experiments may have been confounded by less-defined culture media and organ dissection techniques, because the results are not reproducible in our hands. The authors undertook a study to reexplore these basic epithelio-mesenchymal interactions. METHODS: Using previously described organ dissection and culture techniques the authors examined the basic interactions between the embryonic pancreatic epithelium and its mesenchyme with histological and immunohistological techniques. RESULTS: The authors found that, contrary to previous reports, the earliest pancreatic anlage did not possess the intrinsic signaling necessary to support normal growth and differentiation in vitro. Intimate contact between the epithelium and the mesenchyme may be necessary until E11.5 for normal growth and differentiation. The age of the mesenchyme seemed to correlate with the degree of acinar differentiation, and proximity of mesenchyme was important for acinar differentiation. CONCLUSIONS: Previous investigations into the basic epithelio-mesenchymal interactions in the developing mammalian pancreas may have had confounding factors. Extrinsic signals seem necessary for complete pancreatic differentiation, and mesenchymal factors appear important for acinar differentiation.

Vascular development in the mouse embryonic pancreas and lung.

PURPOSE: The purpose of this study was to analyze the formation of blood vessels in the developing mouse pancreas and lung by studying two ligands, angiopoietin-1 (ang1) and angiopoietin-2 (ang2), which are thought to play a role as angiogenesis-activating factors in development. Understanding the role of vasculogenic peptides in normal embryonic development also may have important implications for common clinical problems regarding neonatal pulmonary vasculature. METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) as well as Southern blotting was used to determine the ontogeny of angiopoietin-1 and angiopoietin-2 gene expression in the embryonic mouse pancreas and lung. Immunohistochemistry was performed for von Willebrand factor, a known marker of endothelial cells, to chronicle the development of the vasculature in these organs. RESULTS: The authors determined the temporal expression of angiopoietin-1 and angiopoietin-2 as a function of gestational age. RT-PCR data demonstrated expression of ang1 and ang2 in the developing mouse lung between gestational day E9.5 and postnatal day 1, and in the developing pancreas between gestational days E12.5 and E18.5. Southern blot analysis confirmed PCR data for ang2 expression in both the lung and pancreas. The authors also traced the spatial development of the vascular system by von Willebrand factor staining. For both lung and pancreas specimens, no blood vessels were identifiable by immunohistochemistry until embryonic day 12.5. With increased gestational age, the blood vessel networks grew larger. CONCLUSION: The authors have demonstrated that ang1 and ang2 may be involved in the mechanisms of vascular development in the embryonic mouse lung and pancreas.

Esophageal atresia with tracheoesophageal fistula: suggested mechanism in faulty organogenesis.

BACKGROUND/PURPOSE: The organogenesis of esophageal atresia with tracheoesophageal fistula (EA-TEF) is unknown. Using an established model for EA-TEF in rats, the authors proposed to study this aberrancy of development in the hope of gaining insight into its mechanism of formation. METHODS: Pregnant Sprague-Dawley rats were injected with 2.2 mg/kg of Adriamycin intraperitoneally on days 6 through 9 of gestation. Using microdissection, the trachea, blind-ending esophagus, TEF, and stomach were isolated from embryos of various gestional ages. The specimens were analyzed histologically with routine H&E staining. RESULTS: The classic EA-TEF developed in the embryos, with proximal EA and distal TEF. As expected, the atresia formed as a blind-ending pouch, but the distal fistula began as an apparent equal trifurcation of the tracheal anlage into two mainstem bronchi and the fistula tract leading to the stomach. Histological analysis of the fistula tract showed respiratorylike pseudostratified columnar epithelium. CONCLUSIONS: TEF develops as the middle branch of a tracheal trifurcation. EA-TEF occurs by a primary atresia of the esophagus. As a secondary phenomenon, the distal foregut anlage is switched toward the pulmonary phenotype. It trifurcates, and its middle branch grows caudally to fistulize into the stomach.

Selective aortic perfusion and oxygenation: an effective adjunct to external chest compression-based cardiopulmonary resuscitation.

OBJECTIVES: The purpose of this study was to compare the perfusion pressure and rate of return of spontaneous circulation produced by standard advanced cardiac life support with that resulting from advanced cardiac life support with simultaneous aortic occlusion and proximal infusion with oxygenated fluid. BACKGROUND: Cardiopulmonary resuscitation based solely on external chest compression is unable to achieve return of spontaneous circulation in most patients with cardiac arrest. Adjunctive therapies that enhance myocardial oxygen supply may improve outcomes. METHODS: We conducted a prospective, randomized study in mongrel dogs using a fibrillatory model of cardiac arrest with a 20-min arrest time. Dogs were randomized to two groups. Aortic arch and right atrial micromanometers were placed to measure intravascular pressure. Manual external chest compression was used and standardized to an esophageal pulse pressure of 50 mm Hg. Two minutes after initiation of advanced cardiac life support, selective aortic perfusion and oxygenation were initiated in dogs assigned to one group by inflation of an occluding balloon in the descending aorta and infusion of 450 ml of ultrapurified polymerized bovine hemoglobin through a large bore central infusion port. RESULTS: Maximal aortic pressure during standard advanced cardiac life support was 42 +/- 23 (mean +/- SD) versus 69 +/- 28 mm Hg during advanced cardiac life support with selective aortic perfusion and oxygenation. Maximal coronary perfusion pressure during standard therapy was 33 +/- 21 versus 62 +/- 26 mm Hg during combined therapy. Only 2 of 10 dogs receiving standard therapy had return of spontaneous circulation versus 6 of 7 dogs receiving combined therapy. Balloon occlusion alone did not increase perfusion pressure significantly. CONCLUSIONS: The use of selective aortic perfusion and oxygenation increases aortic and coronary perfusion pressures during cardiopulmonary resuscitation, resulting in a large increase in the rate of return of spontaneous circulation. This technique may be an effective adjunct to advanced cardiac life support based on any method of external chest compression and may improve the poor prognosis of patients with cardiac arrest.

The effect of global ischemia and reperfusion on the plasma levels of vasoactive peptides. The neuroendocrine response to cardiac arrest and resuscitation.

OBJECTIVE: Return of spontaneous circulation with CPR is a function of coronary perfusion pressure, which is determined by vasomotor tone and the force of compression. Vasomotor tone is affected by the relative stimulation of arterial vasoconstricting and vasorelaxing receptors by vasoactive substances. We measured the plasma levels of the endogenous vasoactive peptides arginine vasopressin (AVP) angiotensin II (ANG-II) and atrial natriuretic peptide (ANP) during cardiac arrest and resuscitation. DESIGN: A fibrillatory canine model of canine arrest was used. 'Down time' was greater than 10 min, during which no therapy, including BLS, was given. Standard ACLS was initiated at the end of the down time with manual external chest compression standardized to an esophageal pulse pressure of 50 mmHg. Blood samples were collected through an aortic catheter during spontaneous circulation and 3 min after initiation of ACLS. Peptide levels were measured using standard RIA techniques. Results are reported as the mean +/- S.D. in pg/ml. RESULTS: AVP levels increased from a baseline of 1.7 +/- 1.0 pg/ml during spontaneous circulation to 29.9 +/- 33.3 during cardiac arrest and CPR (P = 0.01). There was a moderate positive correlation between aortic pressure and circulating AVP levels after the first dose of epinephrine (R = 0.5). There was a trend towards higher AVP levels in animals with return of spontaneous circulation (P = 0.12). ANG-II levels increased from a baseline of 14.7 +/- 12.9 pg/ml during spontaneous circulation to 151 +/- 105 during cardiac arrest and CPR (P < 0.05). ANP levels increased from a baseline of 55 +/- 46 pg/ml during spontaneous circulation to 293 +/- 73 during cardiac arrest and CPR (P < 0.01). CONCLUSION: There were significant increases in the levels of these endogenous vasoactive peptides. This reflects the neuroendocrine response to global ischemia and CPR reperfusion. Plasma levels of these peptides may effect the vital organ perfusion pressures, response to exogenous vasopressors, and outcome of resuscitative efforts. Future therapies may be directed at enhancing or blocking the effect of these peptides so as to optimize perfusion pressure which is one of the principle determinants of outcome during CPR.

Type A behaviour pattern: a concept revisited.

It is generally accepted that the type A behaviour pattern is a risk factor in the development of coronary artery disease (CAD). Type A people have been characterized as hard-driving, competitive, aggressive and hurried. A number of investigators have attempted to correlate these facets of type A behaviour with increased risks of CAD. However, there have been conflicting results, primarily owing to differences in methods and CAD outcomes and inconsistencies associated with measuring the type A behaviour pattern. As a result, researchers have begun to focus on subcomponents of the type A behaviour pattern, particularly hostility and anger, that appear to be more reliable predictors of CAD outcome. A reconceptualization of the type A behaviour pattern is required.

The effects of anxiety management training on the control of juvenile diabetes mellitus.

The present study was designed to determine whether diabetic control could be improved through the direct psychological management of stress and anxiety. Five poorly controlled female adolescent diabetics ranging in age from 15 to 18 years were used as subjects. All were seen on an outpatient basis over a 6-month period. A single-subject format employing a multiple-baseline design across subjects was used. The independent variable used was a technique known as anxiety management training. Baseline, attention-control, and treatment data were collected on a number of dependent measures. Subjective estimates of anxiety and tension by each subject were gathered on a biweekly basis using the Multifactorial Scale of Anxiety. Diabetic control was assessed daily using the Diastix method and weekly using the 24-hr quantitative glucose method. Data on the five subjects suggested that improved control of stress and anxiety had a positive effect on diabetic regulation. Lower and more stable urine glucose levels using both urine testing methods were found. However, no decreases in the subjects' personal assessment of tension and anxiety were evident.

Migration of lymphoblasts to the small intestine. III. Strain differences and relationship to distribution and duration of Trichinella spiralis infection.

In NIH strain mice, in which the majority of Trichinella spiralis are located in the anterior half of the small intestine early in the enteral phase of infection, enhanced localization of mesenteric lymphoblasts, nylon wool separated mesenteric T-lymphoblasts and even oxazolone sensitized peripheral lymphoblasts is most prominent in the anterior region of the small intestine. As the worms move to the posterior half of the small intestine, enahnced localization of lymphoblasts is observed in that region only. In BALB/c mice, in which most of the worms are located in the posterior half of the small intestine, enhanced localization of lymphoblasts is primarily in that region. Expulsion of the worms commences within 2--3 days of a large increase in the number of lymphoblasts localizing in the anterior region of the small intestine in NIH strain mice and likewise follows a second and larger increase in the number of lymphoblasts localizing in the posterior region of the small intestine of BALB/c mice.