Breast MRI: Early experience with a 3-D fat-suppressed Gradient Echo Sequence in the evaluation of breast lesions

The early clinical experience with a 3-Dimensional Fourier Transform Gradient Echo sequence with fat suppression in the evaluation of breast masses is reported. Ten female patients with breast malignancies were pre-operatively evaluated with this sequence and the results compared with the pathological specimens. The scanning protocol included a noncontrast sequence followed by an immediate post-contrast sequence (completed 4.5 min after intravenous contrast injection) and a delayed sequence. Images were assessed for maximum lesion and parenchymal enhancement, lesion size and additional enhancing abnormalities. In six patients, malignant masses enhanced maximally on the immediate post-contrast sequence with parenchyma enhancing maximally on delayed images. In three cases, there was preferential enhancement of malignant lesions over normal parenchyma but to a similar degree on both post-contrast sequences. In one case, both the lesion and parenchyma enhanced maximally on the delayed sequence. Magnetic resonance assessed lesion size accurately and also detected satellite malignancies in one case. However, lesion grade, associated in situ carcinoma and lymphovascular invasion did not impact on lesion enhancement. In this small series, a contrast-enhanced, fat-suppressed 3-D Gradient Echo Sequence detected breast carcinoma with high sensitivity. The technique holds promise but further evaluation is required.     

Treatment of conjunctival papillomata with topical interferon Alfa-2b

PURPOSE: Two patients with biopsy-proven conjunctival papillomata exhibited complete resolution after treatment with topical Interferon Alfa-2b (IFNalpha2b). DESIGN: Interventional case reports. METHODS: Two patients with monocular biopsy-confirmed conjunctival papillomata were treated with IFNalpha2b, 1 million units/cc, one drop four times daily until clinical resolution was achieved. RESULTS: (Patient 1) The lesion's size was significantly reduced at 1 month. Complete resolution was noted at the 3-month visit. No recurrences were seen 40 months post-treatment. (Patient 2) The lesion completely resolved after 6 weeks of treatment. No recurrence has occurred 18 months post-treatment. No systemic or local side effect of treatment was noted. CONCLUSIONS: Two sizable conjunctival papillomata resolved using topical IFNalpha2b alone. Interferon is usually not considered effective for large solid tumors without surgical debulking. We realize that this is a limited case series, but these cases may serve as a basis for further investigation.     

Mathematics and the gap junctions: in-phase synchronization of identical neurons

A close consideration of some mathematical results with regards to neuronal synchronization mechanisms are examined. It is well known that intercellular coupling via gap junctions normally occurs between identical neurons, such as the coupling between inhibitory interneurons belonging to the same class. It is unknown why this should happen. The theory of coupled oscillators offers some explanations to answer the questions of the functional role of electrical interactions mediated by gap junctions and the necessity to couple identical neurons. The inference presented here from the mathematical results is that only if the cells are identical will their firing synchronize in-phase. Thus, we propose the concept that the functional role of gap junctional electrical coupling is to synchronize neurons in-phase and therefore this type of coupling will be found between neurons belonging to the same class.     

VALsartan In Acute myocardial iNfarcTion (VALIANT) trial: baseline characteristics in context

BACKGROUND: The VALsartan In Acute myocardial iNfarcTion (VALIANT) trial compared outcomes with: (1) angiotensin-converting enzyme inhibition (ACEI) with the reference agent captopril; (2) angiotensin-receptor blockade (ARB) with valsartan; or (3) both in patients with heart failure (HF) and/or left ventricular systolic dysfunction (LVSD) after myocardial infarction (MI). AIMS: a goal of this active-control trial was to simulate conditions that would lead current practitioners to use ACEIs. Thus, we compared characteristics of VALIANT patients with those of patients in placebo-controlled trials that established ACEIs as standard treatment. METHODS AND RESULTS: We collected demographic, clinical, medication and imaging information from 14703 patients in 24 countries. This high-risk population was a median 65.8 years old, and 31.1% were female. Most (51.8%) showed imaging evidence of LVSD at enrollment. Most (72%) had Killip class>/=II HF. Patients received evidence-based therapies at rates similar to those of contemporary MI trials and at an improved rate compared with prior placebo-controlled ACEI trials. CONCLUSION: VALIANT represents the largest globally representative cohort enrolled with HF and/or LVSD after MI. Patients were similar to those in placebo-controlled ACEI trials while reflecting improvements in evidence-based care. With enrollment complete, VALIANT is poised to define the optimal strategy for renin-angiotensin system blockade after MI to improve cardiovascular outcomes.     

Aspergillus endocarditis in chronic granulomatous disease

We report the first case, to our knowledge, of Aspergillus endocarditis in chronic granulomatous disease in a patient who also had an atrial septal defect. A diagnosis was made on culture of the organism from the mass despite extensive prior investigation. The presence of distinctive skin lesions as a diagnostic clue of fungaemia is highlighted. Possible advances in diagnosis by detection of fungal cell wall components and in prophylaxis by use of itraconazole are referred to. We conclude that fungal endocarditis should be considered in this condition, especially in the presence of a structural heart defect.     

Bursting in inhibitory interneuronal networks: A role for gap-junctional coupling

Much work now emphasizes the concept that interneuronal networks play critical roles in generating synchronized, oscillatory behavior. Experimental work has shown that functional inhibitory networks alone can produce synchronized activity, and theoretical work has demonstrated how synchrony could occur in mutually inhibitory networks. Even though gap junctions are known to exist between interneurons, their role is far from clear. We present a mechanism by which synchronized bursting can be produced in a minimal network of mutually inhibitory and gap-junctionally coupled neurons. The bursting relies on the presence of persistent sodium and slowly inactivating potassium currents in the individual neurons. Both GABAA inhibitory currents and gap-junctional coupling are required for stable bursting behavior to be obtained. Typically, the role of gap-junctional coupling is focused on synchronization mechanisms. However, these results suggest that a possible role of gap-junctional coupling may lie in the generation and stabilization of bursting oscillatory behavior.     

Response time of the Narkotest anesthetic gas monitor

Response time (RT) of the Narkotest anesthetic gas monitor was measured for 7 inhalation anesthetics, using a 5 L/min fresh gas flow (FGF). Time to 63 percent of maximum response (RT63) and to 95 percent of maximum response (RT95) was directly related to rubber/gas and oil/gas partition coefficients. RT95 ranged from 7 seconds for N2O to 843 seconds for methoxyflurane. RT measured at 0.5 L/min FGF was markedly prolonged over RT at 5 L/min. When the Narkotest was placed on the expiratory limbs of circle-absorber breathing circuits, the difference between the calibrated Narkotest reading (Fn) and the mixed expired circuit concentration (Fc) was shown to depend on the rate of increase of the circuit concentration.     

Regional myocardial dysfunction: evaluation of patients with prior myocardial infarction with fast CT

A prototype ultrafast cine computed tomographic (CT) scanner, designed specifically for cardiac imaging, was used to evaluate a preliminary series of patients with prior myocardial infarction (n = 21) and a control group without coronary artery disease (n = 5). Multilevel 50-msec CT scan exposures were obtained during peripheral intravenous bolus injections of contrast medium. A comparison was made between cine-CT scans and standard left ventriculographic images in assessing segmental left ventricular motion. Results indicate that cine CT, performed at sufficiently rapid speeds (20 scans per second) to allow useful analysis of regional ventricular wall motion, can provide adequate image quality. Analysis of 110 segments revealed a good correlation (90.9%) between the two techniques in characterizing normal from abnormal regional wall motion. Cine CT, based on this initial study, demonstrates considerable potential for evaluating not only cardiac chamber dimensions but also segmental wall dynamics.