Cyclic AMP inhibits increased collagen production by cyclically stretched smooth muscle cells

Rabbit arterial smooth muscle cells, grown on elastin membranes which were cyclically elongated and relaxed, responded by increasing their rates of synthesis of protein and, in particular, of collagen, compared to stationary controls. Raising intracellular cyclic AMP (cAMP) levels by adding theophylline or dibutyryl cAMP to the culture medium prevented the synthetic response to cyclic stretching, but did not alter the rates of protein or collagen synthesis by stationary controls. Both synthesis and degradation of collagen by cyclically stretched cells increased in parallel such that the proportion of synthesized collagen that was degraded was similar to that found in the stationary cultures. Collagen degradation was not affected by theophylline administration to stationary cell cultures but the drug increased degradation of collagen by cyclically stretched cells. We conclude that the net production of protein, and in particular of a structural protein, collagen, by arterial smooth muscle cells subjected to the mechanical force of stretching was inhibited when intracellular levels of cAMP were raised. The results suggest that cAMP may play a role in the modulation of structural protein content of artery walls in response to changes in tensile stress.     

The Fetal Patient: Coordinated Care for Families

Complete and accurate knowledge is critical to parent decision making for families with complex and/or life-threatening fetal conditions. Comprehensive fetal centers are available to provide multidisciplinary specialized assessment, evaluation, diagnosis, and nondirectional counseling. Interventional option may include fetoscopic procedures, open fetal surgery, and ex utero intrapartum treatment. The nurse coordinator serves as the family and health care provider liaison for arrangement of services and communication of the plan of care.     

Impaired Personal Boundaries: A Proposed Nursing Diagnosis

topic . How impaired personal boundaries play a significant role in mental illnesses and co-dependency.
purpose . To demonstrate the value of having a formal nursing diagnosis of "impaired personal boundaries."
source . A concept analysis of personal boundaries, which describes the physical, emotional, intellectual, and spiritual dimensions of personal boundaries.
conclusion . The author recommends a new nursing diagnosis of "impaired personal boundaries," which provides a basis for the plan of care for clients with this difficulty.     

Lung tissue rheology and 1/f noise

The mechanical properties of lung tissue are important contributors to both the elastic and dissipative properties of the entire organ at normal breathing frequencies. A number of detailed studies have shown that the stress adaptation in the tissue of the lung following a step change in volume is very accurately described by the functiont ^−k for some small positive constantk. We applied step increases in length to lung parenchymal strips and found the ensuing stress recovery to be extremely accurately described byt ^−k over almost 3 decades of time, despite the quasi-static stress-length characteristics of the strips being highly nonlinear. The corresponding complex impedance of lung tissue was found to have a magnitude that varied inversely with frequency. We note that this is highly reminiscent of a phenomenon known as 1/f noise, which has been shown to occur ubiquitously throughout the natural world. 1/f noise has been postulated to be a reflection of the complexity of the system that produces it, something like a central limit theorem for dynamic systems. We have therefore developed the hypothesis that thet ^−k nature of lung tissue stress adaptation follows from the fact that lung tissue itself is composed of innumerable components that interact in an extremely rich and varied manner. Thus, although the constantk is no doubt determined by the particular constituents of the tissue, we postulate that the actual functional form of the stress adaptation is not.     

Filamentous actin bundles in the kidney

The distribution of filamentous actin bundles in the rat kidney was studied using a fluorescent phallotoxin label and transmission electron microscopy. The microvillous brush border lining proximal tubules, smooth muscle in renal vessels, and renal corpuscles were the structures most intensely labeled with rhodamine phalloidin. Closer evaluation of renal corpuscles revealed intense labeling of filamentous actin within podocyte foot processes enveloping the glomerular capillary loops. Rhodamine phalloidin also labeled basal bands of filamentous actin in the parietal epithelium and basal bands of actin in proximal and distal tubules. Finally, a band of filamentous actin was evident along the innermost aspect of the kidney capsule, within cells which often joined to form sinus-like compartments.     

Sputum microbiome profiles identify severe asthma phenotypes of relative stability at 12 to 18 months

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Evaluation of method for secondary DNA typing of Mycobacterium tuberculosis with pTBN12 in epidemiologic study of tuberculosis.

Secondary fingerprinting of Mycobacterium tuberculosis DNA with a probe containing the polymorphic GC-rich repetitive sequence present in pTBN12 has been found to have greater discriminating power than does fingerprinting with the insertion sequence IS6110 for strains carrying few copies of IS6110. To validate the use of pTBN12 fingerprinting in the molecular epidemiology of tuberculosis, M. tuberculosis isolates from 67 patients in five states in the United States and in Spain were fingerprinted with both IS6110 and pTBN12. Epidemiologic links among the 67 patients were evaluated by patient interview and/or review of medical records. The 67 isolates had 5 IS6110 fingerprint patterns with two to five copies of IS6110 and 18 pTBN12 patterns, of which 10 were shared by more than 1 isolate. Epidemiologic links are consistently found among patients whose isolates had identical pTBN12 patterns, whereas no links were found among patients whose isolates had unique pTBN12 patterns. This suggests that pTBN12 fingerprinting is a useful tool to identify epidemiologically linked tuberculosis patients whose isolates have identical IS6110 fingerprints containing fewer than six fragments.