Radiofrequency power deposition utilizing thermal imaging.

Wavelength effects influence radiofrequency (RF) power deposition distributions and limit magnetic resonance (MR) medical applications at very high magnetic fields. The power depositions in spherical saline gel phantoms were deduced from proton resonance shift thermal maps at both 1.5 T and 3.0 T over a range of conductivities. Phase differences before and after RF heating were measured for both a quadrature head coil and a circular surface coil. A long echo time (TE) pulse sequence with a 3D phase unwrap algorithm provided increased thermal sensitivity. The measured thermal maps agreed with a model of eddy-current heating by circularly polarized oscillating RF fields in a conducting dielectric sphere. At 3.0 T, thermal maps were acquired with a <0.32 degrees C temperature rise at 4 W. Proton resonance shift thermal maps provided a measure of hot spots in very-high-field MR imaging (MRI), in which both the phase sensitivity and signal-to-noise ratio (SNR) were increased. The method provides a means of studying the heat distribution generated by RF coils excited by clinical pulse sequences.     

Clostridium difficile infection: An overview of the disease and its pathogenesis, epidemiology and interventions

Clostridium difficile infection (CDI) is the primary cause of antibiotic-associated diarrhea and is a significant nosocomial disease. In the past ten years, variant toxin-producing strains of C. difficile have emerged, that have been associated with severe disease as well as outbreaks worldwide. This review summarizes current information on C. difficile pathogenesis and disease, and highlights interventions used to combat single and recurrent episodes of CDI.     

A multidisciplinary checklist for management of suspected placenta accreta

Rates of abnormally invasive placentation have been escalating. The condition requires meticulous planning to ensure safety at delivery. Although placenta accreta remains the most common reason for Caesarean hysterectomy in developed nations, medical and surgical therapies have allowed fertility preservation. Most planning strategies start with risk factor assessment and diagnostic imaging. Early planning of arrangements for antepartum and intrapartum management is preferable to late planning, when emergency situations are more likely to occur. Based on maternal and fetal morbidities, and published evidence of factors that may diminish these risks, we have developed a checklist to aid the antepartum and intrapartum management of potentially challenging cases of invasive placentation or to aid in considering tertiary care consultation and transfer. The proposed checklist may best benefit physicians working in primary and secondary levels of care in Canada. Ideally, this checklist would be available in electronic form, with alerts as needed; a copy of the checklist should be kept in the patient's medical chart, with periodic updates.     

Placenta previa is not an independent risk factor for a small for gestational age infant

Previous studies have presented conflicting evidence on the association between intrauterine growth retardation (IUGR) and placenta previa, with some groups reporting rates of IUGR as high as 16-19%. However, most of these studies failed to include a control population, included patients with other factors known to be associated with IUGR (eg, chronic hypertension, fetal anomalies, pregnancy-induced hypertension, insulin-dependent diabetes mellitus, etc), and/or did not confirm the patient's estimated gestational age. During the study period of January 1, 1980 through June 30, 1990, 54,969 deliveries occurred at the three affiliated hospitals of the Maternal-Fetal Medicine Division of the University of Connecticut Health Center. Review of the delivery records revealed 179 singleton pregnancies with documented placenta previa and without the above exclusion factors. One hundred seventy-one of these 179 study patients were compared with 171 women without placenta previa matched for confirmed gestational age, race, parity, and fetal sex. The incidence of small for gestational age (SGA) infants was 4.1% (seven of 171) in the study group and 5.8% (ten of 171) in the control group. Mean birth weights were 2559 and 2476 g, respectively. Neither difference was statistically significant. These results suggest that the prenatal diagnosis of an SGA fetus in a pregnancy complicated by placenta previa should not simply be attributed to abnormal placental implantation. Furthermore, routine ultrasonic examinations for growth in pregnancies complicated by placenta previa are not indicated.     

Circadian Variations in Gastric Acid and Pepsin Secretion and Intragastric Bile Acid in Patients with Reflux Esophagitis and in Healthy Controls

Objectives : Duodenogastric reflux is a physiological phenomenon in both fasting and postprandial state. Because this suggests that bile acids may reflux into the esophagus together with the acid in patients with reflux esophagitis, we investigated the circadian variations of acid and pepsin secretion and intragastric bile acid concentrations in 25 patients with reflux esophagitis and in 15 healthy controls. Methods : Between-meal, nocturnal gastric and meal-stimulated acid and pepsin secretion and bile acid concentrations were measured by continuous gastric aspiration and intragastric titration. Results : Bile acids were found in 85 and 59% of gastric samples ( p < 0.05). Intragastric bile acid concentrations were 6–8-fold higher in esophagitis patients than controls during the day. Approximately 10% of gastric samples from reflux esophagitis patients had a pH greater than 7, and all contained more than 500 μmol/L bile acids. Bile acids and pepsin were simultaneously revealed in 98% of the gastric samples from patients with reflux esophagitis with pH less than 4. Mean daily acid output (meal excluded) averaged 3.5 ± 0.1 in healthy subjects and 2.7 ± 0.2 mmol/30 minutes in esophagitis patients ( p < 0.05); meal-induced acid secretions were similar. Total (24-h) acid secretion averaged 192.3 ± 12.4 and 162.4 ± 10.5 mmol/24 h ( p < 0.05). There were no differences in the daily pepsin output. Conclusions : Our data indicate that almost all "acid" gastroesophageal refluxes should be considered as "mixed" refluxes. Because bile acids are found in the stomach irrespective of whether the environment was acid or alkaline, pH-metry provides no useful information on the pattern of duodenogastric reflux into the esophagus. Variability in the composition of the gastroesophageal refluxate may explain why the severity of esophageal lesions differs in patients with similar pattern of acid refluxes.     

Effects of 2,5-hexanedione on the ovary and fertility. An experimental study in mice.

Sixty-day-old virgin female Swiss CD1 mice were treated with 1.5% 2,5-hexanedione in their drinking water; control mice received tap water; duration of treatment was either 4 or 6 weeks. Under these conditions the treated mice did not show any clinical symptoms although electromyography revealed some signs of polyneuropathy. Protein and DNA content per mg of ovarian tissue in treated mice were not significantly different from controls. Histological examination of ovarian sections at the light microscope level showed no significant alterations after exposure. A morphometric study revealed a statistically significant reduction in the number of growing oocytes after 6 weeks of treatment. For fertility studies three groups of 15 female mice each were treated for 0, 4 or 6 weeks as above and then permanently housed with untreated proven breeder male mice (one male per female); cages were checked daily for newly born mice. All litters appeared normal by gross examination. During the first 14 weeks of continuous mating the mean litter size (number of newborns per litter) remained about 11.4 in all groups; this number subsequently began to decrease. Control and 4-week treatment regression curves did not differ statistically, while the slope of the 6-week line was significantly steeper, indicating a faster decrease in litter size over time and a shortening of fertile life in the latter group of treated females.     

In-hospital mortality in patients with renal dysfunction admitted for myocardial infarction: the Emilia-Romagna region of Italy database of hospital admissions

Background

In-hospital mortality of patients with myocardial infarction (MI) in different European populations and renal dysfunction is variable. We aimed to evaluate in-hospital mortality for MI in chronic kidney disease (CKD), in end-stage renal disease (ESRD), and in subjects admitted for MI without renal dysfunction living in the Emilia-Romagna region of Italy.

Methods

We considered all cases of MI (first event) recorded in the database of hospital admissions of the region Emilia-Romagna of Italy, from January 1999 to December 2009. The criterion for inclusion was the presence, as a first discharge diagnosis, of acute MI (International Classification of Diseases, 9th Revision, Clinical Modification). The Charlson comorbidity index (CCI), with the exclusion of CKD, was calculated. The outcome variable was in-hospital mortality for MI, and its association with comorbidities, CKD and ESRD, was analyzed.

Results

During the considered period, 88,014 cases of first MI were recorded. The percentage of patients admitted with MI and died during hospitalization were higher in patients with ESRD (38.3 %) and CKD (16.5 %) than in those without renal dysfunction (14 %) (p < 0.01). In CKD and ESRD patients, data of in-hospital mortality for MI exhibited a twofold increase in the analyzed period. In-hospital mortality for MI was independently associated with age (OR 1.077, 95 % CI 1.075–1.080, p < 0.001), CCI excluding CKD (OR 1.101, 95 % CI 1.069–1.134, p < 0.001), cerebrovascular disease (OR 1.450, 95 % CI 1.349–1.557, p < 0.001), malignancy (OR 1.234, 95 % CI 1.153–1.320, p < 0.001), and ESRD (OR 4.137, 95 % CI 3.511–4.875, p < 0.001).

Conclusions

As for the Emilia-Romagna region of Italy, in-hospital mortality for MI is increasing over the last years, and mortality seems to be related with patients’ comorbidities and presence of advanced stages of CKD.