Distribution of lung disease

Radiologists rely on imaging patterns to arrive at a diagnosis. The different morphological patterns in the lungs are well known, but less emphasis has traditionally been placed on the pattern of distribution. This important feature greatly assists in the differential diagnosis regarding many pulmonary diseases and is the focus of this article. Chest radiographs often result in a narrow differential if one understands the regional differences and microenvironments within the lung and takes into consideration the ancillary imaging findings. High-resolution computed tomography offers additional information at the level of the secondary pulmonary lobule to fine-tune the distribution pattern and, consequently, the differential diagnosis. Disease distribution is often as important as the morphologic appearance of the disorder. This article will approach pulmonary diseases from the perspective of distribution patterns, highlighting the more common patterns. The goal of this review article is to give radiologists a conceptual framework that may be applied in their daily work environment.     

Linked Activity of Neurons in the Sensorimotor Cortex of the Rabbit in the State of a Defensive Dominant and “Animal Hypnosis”

A cryptic focus of excitation (a dominant focus) was created in the brains of rabbits by threshold stimulation of the left limb with a current at a frequency of 0.5 Hz. After creation of a focus, there were equal probabilities of detecting pairs of neurons whose linked activity was dominated by a 2-sec rhythm in the sensorimotor cortex of both the right and left hemispheres (29.3% and 32.4%, respectively). When animals were placed in “animal hypnosis,” the total proportion of neuron pairs whose activity was dominated by the rhythm created by establishment of the dominant decreased significantly only in the right hemisphere (21%). After exiting the state of animal hypnosis, the proportion of neurons in the cortex of the right hemisphere whose activity was dominated by the 2-sec rhythm increased significantly if the neurons in the pair were close-lying but decreased significantly if the neurons in the pair were mutually distant. No such changes after hypnotization were seen in the cortex of the left hemisphere. In both the right and left hemispheres, dominance of the 2-sec rhythm in the activity of pairs of neurons was seen significantly more frequently when cross-correlation histograms were constructed by analyzing cells in relation to the spike activity of neurons generating spikes of the lowest (right hemisphere) or lowest and intermediate (left hemisphere) amplitude on neurograms of multineuron activity. Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 58, No. 2, pp. 183–193, March–April, 2008.     

Healing of gastric mucosal erosions induced by indomethacin and restoration of glucocorticoids levels in the blood of rats

The study was made of the effects of low production of glucoorticoids and subsequent replacement with these hormones on healing of hemorrhagic erosions of rat gastric mucosa emerging 4 hours after administration of indomethacin (25 mg/kg percutaneously). Corticosteroid deficiency was produced by adrenalectomy or blocking function of the hypothalamo-hypophyseo-adrenocortical system by introduction of supraphysiological dose of hydrocortisone i week before indomethacin administration. Replacement therapy was conducted 4 hours after indomethacine administration by subcutaneous injection of corticosterone in a dose of 4 mg/kg. Healing was evaluated by changes in the area of damaged surface of gastric mucosa for 2 days after indomethacin administration. Plasma levels of corticosteroids were controlled. It was found that animals with corticosteroid deficiency had a larger area of mucosal lesion and slow healing vs control rats. Administration of corticosterone in physiological dose to animals with deficient production of corticosteroids stimulated healing of gastric mucosa erosions.     

Robust T-tubulation and maturation of cardiomyocytes using tissue-engineered epicardial mimetics

Complex three-dimensional (3-D) heart structure is an important determinant of cardiac electrical and mechanical function. In this study, we set to develop a versatile tissue-engineered system that can promote important aspects of cardiac functional maturation and reproduce variations in myofiber directions present in native ventricular epicardium. We cultured neonatal rat cardiomyocytes within a 3-D hydrogel environment using microfabricated elastomeric molds with hexagonal posts. By varying individual post orientations along the directions derived from diffusion tensor magnetic resonance imaging (DTMRI) maps of human ventricle, we created large (2.5 × 2.5 cm²) 3-D cardiac tissue patches with cardiomyocyte alignment that replicated human epicardial fiber orientations. After 3 weeks of culture, the advanced structural and functional maturation of the engineered 3-D cardiac tissues compared to age-matched 2-D monolayers was evident from: 1) the presence of dense, aligned and electromechanically-coupled cardiomyocytes, quiescent fibroblasts, and interspersed capillary-like structures, 2) action potential propagation with near-adult conduction velocity and directional dependence on local cardiomyocyte orientation, and 3) robust formation of T-tubules aligned with Z-disks, co-localization of L-type Ca²⁺ channels and ryanodine receptors, and accelerated Ca²⁺ transient kinetics. This biomimetic tissue-engineered platform can enable systematic in vitro studies of cardiac structure–function relationships and promote the development of advanced tissue engineering strategies for cardiac repair and regeneration.     

MHV68 Latency Modulates the Host Immune Response to Influenza A Virus

Murine gammaherpesvirus 68 (MHV68) is a natural rodent pathogen that has been used as a model to study the pathogenesis of human gammaherpesviruses. Like other herpesviruses, MHV68 causes acute infection and establishes life-long latency in the host. Recently, it has been shown that mice latently infected with MHV68 have resistance to unrelated pathogens in secondary infection models. We therefore hypothesized that latent MHV68 infection could modulate the host response to influenza A virus. To test this hypothesis, mice were infected intranasally with influenza virus following the establishment of MHV68 latency. Mice latently infected with MHV68 showed significantly higher survival to influenza A virus infection than did PBS mock-infected mice. Latent MHV68 infection led to lower influenza viral loads and decreased inflammatory pathology in the lungs. Alveolar macrophages of mice latently infected with MHV68 showed activated status, and adoptive transfer of those activated macrophages into mice followed the infection with influenza A virus had significantly greater survival rates than control mice, suggesting that activated alveolar macrophages are a key mechanistic component in protection from secondary infections.     

Comparative Analysis of the Frequency of Neuron Spike Activity in the Sensorimotor Cortex of the Right and Left Hemispheres in Conditions of Immobilization Catatonia in Rabbits

Multineuron activity was recorded from the sensorimotor cortex of the right and left hemispheres during immobilization catatonia in rabbits. The first session of immobilization of the animals was followed by changes in spike frequency in 47% of neurons in the sensorimotor cortex of the right hemisphere. Of these, 30% showed decreases in spike frequency and 17% showed increases. Spike frequency in the sensorimotor cortex of the left hemisphere changed in only 18% of cells, of which 13% showed decreases in spike frequency and 5% showed increases. The spike frequency of neighboring (recorded with the same electrode) neurons could change reciprocally. Differences in neuron activity in the two hemispheres were virtually absent after the second session of immobilization (several days after the first) – spike activity changed in 21% of neurons in the right hemisphere and 24% in the left hemisphere. The ratios of the numbers of neurons with increases and decreases in spike activity in hypnosis also became identical in the cortex of the right and left hemispheres. A hypothesis is proposed for the involvement of cortical neurons in the organization of hypnosis-like states.     

Beta-adrenergic stimulation modulation of heart rate via synchronization of ryanodine receptor Ca2+ release

A robust "fight or flight response", largely mediated via acute beta-adrenergic receptor (beta-AR) stimulation to the heart to increase its beating rate and contractile performance, is an essential component of the vertebrate survival instinct. While it has long been recognized that activation of beta-AR increases the spontaneous beating rate of sinoatrial nodal cells (SANC), specific links between stimulation of beta-ARs and the resultant increase in firing rate have not been evaluated. Our recent studies employed imaging of subcellular Ca2+ release coupled with recording of membrane potential or current in single, isolated cardiac SANC, to seek novel links between beta-AR stimulation and ryanodine receptor Ca2+ release and heart rate. An overview of these recent results, which provides novel insights into mechanisms of cardiac reserve that underlie the "fight or flight instinct, is presented here.     

Clinical picture of open-angle glaucoma in patients with critical stenosis of the internal carotid artery

Clinical picture of primary open-angle glaucoma (POAG) was studied in 32 patients (57 eyes) with pronounced stenosis of the extracranial segment of the internal carotid artery (ICA) on the side of the glaucomatous eye. Major clinical signs were detected: conjunctival angiopathy, pronounced diffuse dystrophy of the iris, absence of pigmented iridal rim, pseudoexfoliations, pale optic disk with saucer-like excavation of different severity. Intraocular pressure (IOP) was 26-34 mm Hg and could not be normalized by drug therapy or antiglaucomatous surgery. Ultrasonic methods for examination of the eyeball vessels showed pronounced decrease of the bloodflow velocity and a significant increase of resistance index in the orbital and central retinal arteries. Reconstructive operations on the carotid arteries performed in POAG patients for critical stenosis of ICA improved the eyeball hemoperfusion and decreased IOP.