Pathogenesis of diarrhea due to escherichia coli

E. coli may produce diarrhea by producing enterotoxins, by invasion of the gut, or by adherence. Their presence in the stools by itself does not establish a cause and effect relationship. To be pathogenic they must be able to colonise the gut. It is possible thatE. coli may also produce diarrhea by hitherto unknown mechanisms.     

Structure-activity profile of a series of novel triazoloquinazoline adenosine antagonists

During a search for benzodiazepine receptor modulators, a highly potent adenosine antagonist (CGS 15943) was discovered. The compound was defined as a resonance-stabilized hybrid of the canonical structures 9-chloro-2-(2-furyl)[1,2,4]triazolo[1,5-c]quinazolin-5-amine (2a) and 9-chloro-2-(2-furyl)-5,6-dihydro[1,2,4]triazolo[1,5-c]-quinazolin- 5-imine (2b). Spectroscopic evidence and chemical reactivity in polar media favor the amine form 2a as the major contributor of the two canonical structures. The synthesis of 2 and some of its analogues and the structure-activity relationships in four biological test systems are described. Replacement of the 9-chloro group by hydrogen, hydroxyl, or methoxyl gave compounds with comparable binding potency at the A1 and A2 receptors but much less activity as antagonists of 2-chloroadenosine in guinea pig tracheal strips. Alkylation of the 5-amino group caused, in general, a loss of binding activity, particularly at the A2 receptor, as well as complete loss of activity in the tracheal model. Modification of the 2-furyl group caused a pronounced loss of activity in all of the test systems.     

Surfactant proteins SP-A and SP-D: structure, function and receptors

Surfactant proteins, SP-A and SP-D, are collagen-containing C-type (calcium dependent) lectins called collectins, which contribute significantly to surfactant homeostasis and pulmonary immunity. These highly versatile innate immune molecules are involved in a range of immune functions including viral neutralization, clearance of bacteria, fungi and apoptotic and necrotic cells, down regulation of allergic reaction and resolution of inflammation. Their basic structures include a triple-helical collagen region and a C-terminal homotrimeric lectin or carbohydrate recognition domain (CRD). The trimeric CRDs can recognize carbohydrate or charge patterns on microbes, allergens and dying cells, while the collagen region can interact with receptor molecules present on a variety of immune cells in order to initiate clearance mechanisms. Studies involving gene knock-out mice, murine models of lung hypersensitivity and infection, and functional characterization of cell surface receptors have revealed the diverse roles of SP-A and SP-D in the control of lung inflammation. A recently proposed model based on studies with the calreticulin-CD91 complex as a receptor for SP-A and SP-D has suggested an anti-inflammatory role for SP-A and SP-D in na?ve lungs which would help minimise the potential damage that continual low level exposure to pathogens, allergens and apoptosis can cause. However, when the lungs are overwhelmed with exogenous insults, SP-A and SP-D can assume pro-inflammatory roles in order to complement pulmonary innate and adaptive immunity. This review is an update on the structural and functional aspects of SP-A and SP-D, with emphasis on their roles in controlling pulmonary infection, allergy and inflammation. We also try to put in perspective the controversial subject of the candidate receptor molecules for SP-A and SP-D.     

Patient-controlled epidural analgesia with fentanyl and bupivacaine provides better analgesia than intravenous morphine patient-controlled analgesia for early thoracotomy pain

Background: Intravenous patient-controlled analgesia (IVPCA) and patient-controlled epidural analgesia (PCEA) were studied in terms of analgesic efficacy, respiratory function and side effects after thoracic surgery for 24h. PCEA using fentanyl and bupivacaine as compared to IVPCA using morphine provides better pain relief both at rest and during coughing and is associated with fewer side effects. Aims: To compare IVPCA and PCEA in terms of analgesic efficacy, respiratory function and side effects after thoracic surgery. Settings and Design: Tertiary care teaching hospital. Prospective, randomized and open study. Materials and Methods: Thirty ASA-I or II patients undergoing thoracotomy were assigned randomly to receive either IVPCA using morphine or PCEA using fentanyl and bupivacaine combination postoperatively. No background infusion was administered in either group. Postoperative evaluation included pain intensity both at rest and during coughing, degree of sedation, arterial blood gas, forced vital capacity (FVC), peak expiratory flow rate (PEFR), presence of side effects such as nausea/vomiting and pruritis at 0, 2, 8, 12 and 24h. The primary outcome of the study was the percentage of patients with analgesia failure defined as VAS>30 despite three consecutive PCA boluses requiring rescue analgesia with intravenous fentanyl. Statistical Analysis: Data were analyzed using t -test, chi2 test and Mann-Whitney test. Results: Significantly less number of patients required rescue analgesia in PCEA group ( P< 0.05). Pain relief was better both at rest and during coughing ( P< 0.05) in PCEA group as compared to IVPCA. Patients in the PCEA group were less sedated and had fewer incidences of side effects, i.e. nausea/vomiting and pruritis. Postoperative FVC and PEFR were reduced significantly compared to baseline only in IVPCA group ( P< 0.05). Conclusion: After thoracic surgery, PCEA using fentanyl and bupivacaine as compared to IVPCA using morphine provides better pain relief both at rest and during coughing and associated with fewer side effects.     

Gross tracheal deviation: airway challenges and concerns--two case reports

Practical guidelines and algorithms may not always help in difficult airway management. Large thyroid swellings may be responsible for several difficulties during the perioperative period, such as distortion of the airway, endocrine disturbances and metabolic effects. We here discuss the airway management of two patients with huge thyroid enlargement and gross tracheal deviation. One of those patients had also retrosternal extension of goiter. Both patients were scheduled for an excision of their colloid goiter.