Transoesophageal echocardiography in heart disease—old technologies, new tricks

Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, ‘new tricks’ in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection, TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.     

In vivo MRI of cancer cell fate at the single-cell level in a mouse model of breast cancer metastasis to the brain.

Metastasis (the spread of cancer from a primary tumor to secondary organs) is responsible for most cancer deaths. The ability to follow the fate of a population of tumor cells over time in an experimental animal would provide a powerful new way to monitor the metastatic process. Here we describe a magnetic resonance imaging (MRI) technique that permits the tracking of breast cancer cells in a mouse model of brain metastasis at the single-cell level. Cancer cells that were injected into the left ventricle of the mouse heart and then delivered to the brain were detectable on MR images. This allowed the visualization of the initial delivery and distribution of cells, as well as the growth of tumors from a subset of these cells within the whole intact brain volume. The ability to follow the metastatic process from the single-cell stage through metastatic growth, and to quantify and monitor the presence of solitary undivided cells will facilitate progress in understanding the mechanisms of brain metastasis and tumor dormancy, and the development of therapeutics to treat this disease.     

Quantification of naturally occurring benzodiazepine-like substances in human breast milk

The possible occurrence of benzodiazepine-like substances in human breast milk was investigated in 35 healthy, newly delivered women who were known not to be taking benzodiazepines. Maternal blood samples and a sample of breast milk were obtained on the fifth post partum day. A radioreceptor technique (lower limit of detection 1.5 ng/ml; difference between duplicates at various concentrations <7%) was used for measuring benzodiazepine-like substances in blood and breast milk (with and without prior extraction). No benzodiazepine-like substances could be demonstrated in any of the blood samples taken from the 35 women. Measurable concentrations of benzodiazepine-like substances were demonstrated in all but 1 of the 35 breast milk samples. The mean concentration of benzodiazepine-like substances for all 35 women was 4.3±2.3 ng/ml (range 0–9.3 ng/ml) expressed as lorazepam. The corresponding value for extracted breast milk was 2.6±1.5 ng/ml (range 0–7.0 ng/ml). There was no association between concentrations of benzodiazepine-like substances in breast milk and maternal age, weight, height and body mass or parity, or the sex of the infant and infant birth weight. We suggest that non-detectable amounts of benzodiazepine-like substances in serum are concentrated in the mammillary glands and excreted in a higher concentration in breast milk. It is less likely that the relevant benzodiazepines are produced in the mammillary glands.     

Toxicity of the blue-green alga (cyanobacterium) Microcystis aeruginosa in drinking water to growing pigs,as an animal model for human injury and risk assessment

Hepatotoxins from blue-green algae are increasingly recognized as a potential hazard in drinking water supplies. The clinical consequences of ingestion include acute or chronic liver injury, with the possibility of enhanced susceptibility to, and growth of, liver tumors. To establish guidelines for water safety requires the demonstration of dose-dependent effects of toxicity and experimental determination of maximum “no-adverse-effect levels.” This paper describes the use of growing pigs as a model for human injury resulting from Microcystis toxins in drinking water. Risk assessment calculations using a series of safety factors are carried out, resulting in a guideline level after incorporating an additional safety factor for tumor promotion of approximately 1.0 μg toxins/L. With the Microcystis used for this trial, that concentration corresponds to 5000 cells/mL. © 1994 by John Wiley & Sons, Inc..     

Artifacts due to stimulus correlated motion in functional imaging of the brain

To assess the effect of stimulus correlated motion on the appearance of functional magnetic resonance images, conventional visual and motor protocols were each performed by four normal volunteers and an image co-registration technique was used to retrospectively monitor subject motion. In three studies synthetic data sets were constructed from single baseline images using the positional information obtained from the co-registration procedure. Cumulative difference images were then created from both the synthetic and functional image sets. Stimulus correlated motion was detected in all eight studies and the synthetic cumulative difference images showed striking similarities to the equivalent functional images in each case.     

Course of depressive symptoms and medication adherence after acute coronary syndromes: an electronic medication monitoring study.

OBJECTIVES: We tested whether improvements in depressive symptoms precede improved adherence to aspirin in patients with acute coronary syndromes (ACS). BACKGROUND: Depression is associated with medication nonadherence in patients with ACS, but it is unclear whether changes in depression impact on adherence. METHODS: Electronic medication monitoring was used to measure adherence to aspirin during a 3-month period in a consecutive cohort of 172 patients (25 to 85 years) recruited within 1 week of hospitalization for ACS. Depressive symptom severity was assessed using the Beck Depression Inventory (BDI) during hospitalization and at 1 and 3 months after hospitalization. Adherence was defined as the percentage of days aspirin was taken as prescribed. RESULTS: Depression severity in hospital was associated with nonadherence in a gradient fashion: 15% of non-depressed patients (BDI score 0 to 4), 29% of mildly depressed patients (BDI score 10 to 16), and 37% of patients with moderately-to-severely depressive symptoms (BDI score >16) took aspirin less than 80% of the time (p = 0.03). A cross-lagged path analytic model revealed that improvements in depressive symptoms in the first month after the ACS were associated with improvements in adherence rates in the subsequent 2 months (standardized direct effect -0.32, p = 0.016). CONCLUSIONS: Diagnosis and treatment of depressive symptoms may improve medication adherence in patients after ACS.     

FUSION OF THE FIRST METACARPOPHALANGEAL JOINT FOR POST-TRAUMATIC CONDITIONS

Fusion of the metarcarpophalangeal joint of the thumb is an accepted treatment in the management of instability or osteoarthritis following trauma to this joint. A review was made of the literature and 30 of the senior author's (RH) patients who had had this operation, in order to determine what effect the operation had on the pain in their thumb, any symptoms of instability, interference with work and daily activities, and strength in the hand. All of the patients achieved bony union and the average angle of fusion was 7.6 degrees of flexion. All of the patients were either satisfied or very satisfied with the results of the operation, and had an average increase of 6.3 points on a 12 point rating scale. However, 48% of patients had some mild intermittent pain and 43% complained of some difficulty with fine motor tasks. Twelve patients were able to attend for formal evaluation including the Jebson and Crawford Hand Function Tests which revealed some decrease in hand function in all of those tested. It was concluded that this method of arthrodesis of the metacarpophalangeal joint of the thumb gives reliable results, with high patient acceptance, but does not result in an entirely normal thumb or hand function.