Clinical review: bacteremia caused by anaerobic bacteria in children

This review describes the microbiology, diagnosis and management of bacteremia caused by anaerobic bacteria in children. Bacteroides fragilis, Peptostreptococcus sp., Clostridium sp., and Fusobacterium sp. were the most common clinically significant anaerobic isolates. The strains of anaerobic organisms found depended, to a large extent, on the portal of entry and the underlying disease. Predisposing conditions include: malignant neoplasms, immunodeficiencies, chronic renal insufficiency, decubitus ulcers, perforation of viscus and appendicitis, and neonatal age. Organisms identical to those causing anaerobic bacteremia can often be recovered from other infected sites that may have served as a source of persistent bacteremia. When anaerobes resistant to penicillin are suspected or isolated, antimicrobial drugs such as clindamycin, chloramphenicol, metronidazole, cefoxitin, a carbapenem, or the combination of a beta-lactamase inhibitor and a penicillin should be administered. The early recognition of anaerobic bacteremia and administration of appropriate antimicrobial and surgical therapy play a significant role in preventing mortality and morbidity in pediatric patients.     

Diastolic dysfunction: can it be diagnosed by Doppler echocardiography?

Heart failure with a normal ejection fraction (HFNEF) predominantly afflicts older, female individuals and is considered to be a consequence of diastolic dysfunction. Doppler echocardiography has become the standard method for identifying and characterizing diastolic function. However, the important distinction between Doppler measures of filling dynamics and true indexes of intrinsic ventricular diastolic chamber properties is not widely appreciated. Herein, we delineate physiologic measures of intrinsic ventricular diastolic function, as determined by pressure volume analysis, and compare and contrast these measures with those derived from Doppler echocardiography. Doppler-derived indexes of ventricular filling do not provide specific information on intrinsic passive diastolic properties, and thus, abnormal filling dynamics do not necessarily equate with intrinsic myocardial diastolic dysfunction. This raises a fundamental question as to whether delayed relaxation and/or stiffened passive properties are the unifying pathophysiologic mechanisms in all patients who present with HFNEF.     

Sensitivity of transthoracic versus transesophageal echocardiography for the detection of native valve vegetations in the modern era.

BACKGROUND: Thirteen years ago, transthoracic echocardiography (TTE) was found to be less sensitive than transesophageal echocardiography (TEE) for native valve vegetations. Since then, harmonic imaging and other advances have improved TTE. How this affects the sensitivity of TTE is unknown. METHODS: Fifty patients with echocardiography-diagnosed endocarditis had TTE and TEE examinations on high-end machines. These were matched for date of study with 50 patients who had TTE and TEE examinations that were negative for vegetations. RESULTS: A total of 51 vegetations were seen on TEE. The sensitivity of TTE for vegetations was only 55% (aortic 50% [12/24]; mitral 62% [16/26]; tricuspid 0% [0/1]). Anatomic valvular abnormalities did not alter the sensitivity of TTE (P =.42 for mitral; P =.97 for aortic valves). However, larger vegetations were more likely to be found by TTE. CONCLUSION: Despite advances in imaging during 12 years, TTE is still insensitive compared with TEE for the detection of native valve vegetations, and fails to demonstrate nearly half of them.     

Rapid gas chromatographic-mass spectrometric analysis of [15n]urea: Application to human metabolic studies

A rapid gas chromatographic-mass spectrometric method for [¹⁵N] urea analysis is described which is based on the formation of a TFA-urea derivative. The method is extremely sensitive, being capable of detecting less than 0.2 atom % excess [¹⁵N]urea in as little as 50 μl of plasma and 10 μl of urine with a coefficient of variation of 11%. The method was used to measure in vivo the disappearance of [¹⁵N]urea from plasma and the incorporation of [¹⁵N]ammonium acetate into [¹⁵N]urea. The values obtained for urea pool size and flux are 4.5 ± 0.30 g nitrogen/total body weight and 16.2 ± 1.34 g nitrogen per 24 h per 1.73 m². Following the ingestion of [¹⁵N]ammonium acetate nearly 90% of the ¹⁵N label was incorporated into [¹⁵N]urea by 30 min.     

The clinical and angiographic spectrum of isolated,nondominant, left circumflex coronary disease

Sixteen of 994 patients with arteriosclerotic heart disease and dominant right coronary arteries had isolated left circumflex obstruction. Of these, 6 patients had significant (75%) narrowing in the main circumflex, 10 in 1 of the marginal branches and 1 in the atrioventricular groove branch. Angina was mild in 5, moderate to severe in 8, and unstable in 1. Four patients had prior myocardial infarction (MI), and 1 had a recent MI complicated by posterior papillary muscle rupture. The EKG was normal in 5, showed an MI in 2, LBBB in 1, RBBB in 2, ST-T wave changes in 3, LVH in 2, and atrial fibrillation in 2. Left ventricular angiography performed in the right anterior oblique projection revealed normal contraction in 9 patients, apical hypokinesis in 4, posterobasal hypokinesis in 1, and diffuse hypokinesis in 2. The left ventricular end diastolic pressure was normal in 11 patients and elevated in 5. The cardiac index was normal in 12 patients and reduced in 2. Isolated, nondominant, left circumflex coronary disease is an uncommon entity in symptomatic patients. However, when present, it may produce significant clinical and hemodynamic impairment.     

The effect of phosphodiesterase inhibitors on the extinction of cocaine-induced conditioned place preference in mice

Several phosphodiesterase inhibitors (PDEis) improve cognition, suggesting that an increase in brain cAMP and cGMP facilitates learning and memory. Since extinction of drug-seeking behavior requires associative learning, consolidation and formation of new memory, the present study investigated the efficacy of three different PDEis in the extinction of cocaine-induced conditioned place preference (CPP) in B6129S mice. Mice were conditioned by escalating doses of cocaine which was resistant to extinction by free exploration. Immediately following each extinction session mice received (a) saline/vehicle, (b) rolipram (PDE4 inhibitor), (c) BAY-73-6691 (PDE9 inhibitor) or (d) papaverine (PDE10A inhibitor). Mice that received saline/vehicle during extinction training showed no reduction in CPP for >10 days. BAY-73-6691 (a) dose-dependently increased cGMP in hippocampus and amygdala, (b) significantly facilitated extinction and (c) diminished the reinstatement of cocaine CPP. Rolipram, which selectively increased brain cAMP levels, and papaverine which caused increases in both cAMP and cGMP levels, had no significant effect on the extinction of cocaine CPP. The results suggest that increase in hippocampal and amygdalar cGMP levels via blockade of PDE9 has a prominent role in the consolidation of extinction learning.     

The interval between prothrombin time tests and the quality of oral anticoagulants treatment in patients with chronic atrial fibrillation

BACKGROUND: The incidence of stroke in patients with atrial fibrillation (AF) can be significantly reduced with warfarin therapy especially if optimally controlled. OBJECTIVES: To evaluate the effect of the interval between consecutive prothrombin time measurements on the time in therapeutic range (INR 2-3) in a cohort of patients with AF on chronic warfarin treatment in the community. METHODS: All INR measurements available from a relatively large cohort of patients with chronic AF were reviewed and the mean interval between consecutive INR tests of each patient was correlated with the time in therapeutic range (TTR). RESULTS: Altogether 251,916 INR measurements performed in 4408 patients over a period of seven years were reviewed. Sixty percent of patients had their INR measured on average every 2 to 3 weeks and most others were followed at intervals of 4 weeks or longer. A small proportion (3.6%) had their INR measured on average every week. A significant decline in the time in therapeutic range was observed as the intervals between tests increased. At one to three weeks interval the TTR was 48%, at 4 weeks interval 45% and at 5 weeks 41% (P<0.0005). A five percent increment in TTR was observed if more tests were performed at multiplications of exactly 7 days (43% vs 48% P<0.0001). CONCLUSIONS: A better control with an increase in the TTR was observed in patients with atrial fibrillation if prothrombin time tests are performed at regular intervals of no longer than 3 weeks.