Serum cytosolic beta-glucosidase activity in a rat model of necrotizing enterocolitis

The diagnosis of necrotizing enterocolitis (NEC) is made from a combination of clinical and radiographic findings. There are no useful screening biochemical markers of intestinal injury. The serum concentration of cytosolic beta-glucosidase (CBG), an enzyme found primarily in enterocytes, is markedly elevated in animal models of ischemia and bowel obstruction. We hypothesized that in a rat model of NEC, serum CBG activity would significantly increase before microscopic evidence of severe intestinal injury. Cohorts of 2-wk-old Sprague-Dawley rats (n = 10/cohort) were anesthetized and underwent laparotomy with occlusion of the superior mesenteric artery (SMA). Platelet-activating factor (200 microg/animal) was injected in the proximal duodenum. Serum and intestinal samples were obtained at time 0 (control) and 30, 60, and 90 min of ischemia (I) and after 90 min of I followed by 60 min of reperfusion (I/R). Histopathologic injury was categorized as either no or minimal injury or mural necrosis by two masked investigators and CBG activity was measured by ELISA. Data were analyzed with Fisher's exact test and ANOVA. Only the I/R group had significantly greater mural necrosis compared with the control group (90% versus 0%, respectively, p < 0.001). In contrast, CBG activity was significantly elevated after only 90 min of I and after I/R (15.1 +/- 5.6 and 16.4 +/- 4.3 units/mL, respectively, p < 0.05). We conclude that serum CBG is elevated before transmural intestinal injury in this model and may have utility as an early marker of ischemia in patients at risk for NEC.     

Pulmonary cystic hydatid disease in Ireland

Background Hydatid disease is rare in Ireland and its incidence and prevalence are unknown. Most cases are diagnosed by a combination of clinical findings, morphological features on imaging and by serological testing. Aims We describe an Irish case of pulmonary hydatid disease detected at bronchoscopy by bronchoalveolar lavage, and discuss the diagnosis and treatment of the disorder.     

Host-pathogen interactions in mycoplasma pathogenesis: virulence and survival strategies of minimalist prokaryotes

Despite their very small genomes mycoplasmas are successful pathogens of man and a wide range of animal hosts. Because of the lack of effective therapeutics and vaccines, mycoplasma diseases continue to be a significant problem for public health as well as livestock production with major socio-economic consequences worldwide. Recent outbreaks and epidemiological studies predict that the incidence of human and animal mycoplasma diseases might increase which indicates the urgent need to develop new approaches for prevention and therapy. Development of such reagents, however, requires a solid understanding of the molecular biology of mycoplasma infections. Knowledge in this field has considerably increased during the past decade since new techniques have been developed and adapted to mycoplasmas that allow these organisms to be studied at the molecular level. Research on the two human pathogens Mycoplasma pneumoniae and Mycoplasma genitalium of which the genome sequences have recently been completed as well as the substantial number of studies carried out on the AIDS-associated mycoplasmas, Mycoplasma penetrans and Mycoplasma fermentans, has led the way, but a number of animal mycoplasmas are becoming increasingly appreciated as models for the study of the molecular basis of mycoplasma diseases. This review summarizes and highlights some of the recent findings concerning the molecular interactions that occur between pathogenic mycoplasmas and their hosts, both the common strategies as well as some unique approaches evolved by particular mycoplasma pathogens, including adherence to and uptake into non-phagocytic host cells, as well as mechanisms of escaping the host immune system.     

Absorption and endogenous faecal excretion of calcium by low birthweight infants on feeds with varying contents of calcium and phosphate

Low birthweight infants aged 4-41 days were given from birth one of three experimental milk formulae varying widely in content of calcium and phosphate. Ca and P in feed, urine, and faeces were measured between carmine markers corresponding to a metabolic period of 48 hours. Calcium enriched in 46Ca to provide a marker for the dietary Ca was added to one feed and 46Ca measured in urine and faeces. True absorption of Ca and endogenous excretion into the bowel could then be inferred. True absorption of Ca was proportional to Ca intake and independent of P intake. Endogenous faecal excretion seemed to be independent of both Ca P intakes, and varied widely between different infants in the range 4-150 mg/day. Urine Ca was low and retention was essentially the difference between true absorption and endogenous faecal excretion. Retention of Ca tended to be much greater on a high Ca intake, but the variability in retention between infants on a given intake was large, paralleling the variability in endogenous faecal excretion. The variability in plasma Ca concentrations in newborn infants may in part be a consequence of wide individual variability in endogenous faecal excretion. The 46Ca marker technique provides a means of investigating the factors determining this variability.     

Prolonged QT interval and cardiac arrhythmias in two neonates: sudden infant death syndrome in one case

Two neonates with arrhythmias and the long QT syndrome are described. The arrhythmias were detected in utero and both infants were apparently well after birth. The first infant, although well, had a bradycardia for the first 9 days of life. A normal heart rate was documented at 10 days but a prolonged QT interval was not appreciated on the ECG. He was discharged from hospital but died suddenly and unexpectedly 3 days later. A post-mortem examination failed to find a cause for his death which therefore fell into the category of the sudden infant death syndrome (SIDS). A retrospective analysis of the perinatal electrocardiogram showed a probable junctional rhythm with 2:1 conduction to the ventricle; the QT interval was prolonged at 0.52 seconds (QTC = 0.63). The second infant had a QT interval of 0.52 seconds (QTC = 0.54) and frequent ventricular premature beats on a 24-hour electrocardiogram. She was treated with propranolol and remains well 2 years later. Sudden infant death has often been described in the siblings of children with the long QT syndrome and one other report described a case of SIDS which was said to have had a prolonged QT interval on the perinatal ECG. This report, however, provides unquestionable evidence, in one case, of an association between the long QT syndrome and SIDS.     

Exogenous lung surfactant: effect on radiographic appearance in premature infants

At birth, premature infants of 25-29 weeks gestation, at high risk for development of neonatal respiratory distress syndrome (RDS), were given a single dose (90 mg) of calf lung surfactant extract (CLSE) by intratracheal instillation. The frequency and severity of RDS were assessed with use of a simple radiographic scoring system in which pulmonary parenchymal densities and the prominence of the air-bronchogram effect were used as indicators of widespread atelectasis. Radiographs were obtained in surfactant-treated and control infants within the first 90 minutes of life as part of an initial evaluation of their pulmonary status. Subsequent examinations were performed at less than 24 hours and less than 48 hours of age. Radiographic assessment of lung disease compared consistently with coordinated data on oxygen and mean airway pressure requirements of the infants. Both indicated a significantly decreased frequency and severity of RDS in the infants treated with surfactant. The results provide supporting evidence of the effectiveness of exogenous lung surfactant replacement in mitigating RDS in very premature infants.     

Meniscal injuries: detection using MR imaging

Both retrospective and blinded analyses of thin-section, high-resolution magnetic resonance (MR) images of the knee joint, produced using a solenoid surface coil, indicate that MR imaging is an effective technique for evaluating meniscal injuries. Images of 49 patients were evaluated, and the results were correlated with those of subsequent arthroscopy. A grading scale was developed to rate the index of suspicion of a meniscal tear based on the MR images. Overall, approximately 80% of menisci rated grade 4 (definite tear) or 3 (probable tear) were found to have corresponding tears at arthroscopy. In many other patients with a grade 4 or 3 meniscus in whom a corresponding tear was not found arthroscopically, meniscal tears at other sites or other abnormalities were correctly diagnosed using MR. A majority of the false-positive MR images involved the posterior horns of the menisci, the sites of most false-negative arthroscopic diagnoses. The predictive value of a negative MR image was almost 100%. Even in patients with moderate-to-large effusions, the menisci were accurately evaluated. The results imply that MR imaging is useful in the preoperative evaluation of suspected meniscal tears.     

Pulmonary embolism after hip or knee replacement: postoperative changes on pulmonary scintigrams in asymptomatic patients

Serial pulmonary imaging has proved to be effective in the evaluation of patients undergoing total joint arthroplasty. A clinical dilemma arises in asymptomatic patients whose postoperative pulmonary images differ from the preoperative images. The authors prospectively evaluated 403 patients with serial imaging to determine the significance of changed postoperative images in asymptomatic patients undergoing total hip or knee arthroplasty. Twenty-two (5.5%) patients had significant changes on postoperative images. Seventeen were asymptomatic; all but one underwent pulmonary angiography. Documented pulmonary emboli were demonstrated in 100% of patients whose postoperative images changed to indicate a high probability of pulmonary embolism, 71% whose images changed to a moderate probability, and 0% whose images changed to indeterminate probability. Overall, pulmonary emboli occurred in 76% of all asymptomatic patients with significantly change postoperative images. Asymptomatic pulmonary embolism is a significant occurrence after total hip or knee repair, and a changed lung scan with appropriate clinical evaluation is an accurate indicator of pulmonary emboli in asymptomatic postarthroplasty patients.