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Biomedical subjects

A Lerman

Publications and source records attributed to A Lerman.

120 records · Page 7Linked to original sources
PubMed1990

Endothelin: a new cardiovascular regulatory peptide.

Endothelin, a recently discovered peptide produced by endothelial cells, contracts vascular strips in vitro with greater potency than any previously known vasoconstrictor. Infusions of pharmacologic doses of endothelin in vivo result in a prolonged pressor response and a preferential impairment of renal hemodynamic and excretory functions. Endothelin also directly stimulates the release of aldosterone from the adrenal gland and inhibits renin release in vitro. A highly sensitive and specific radioimmunoassay has confirmed that endothelin circulates in human plasma, and increased plasma endothelin levels have been associated with various cardiovascular disease states. This review summarizes the current knowledge about the molecular biologic features and physiologic actions of endothelin and also explores the role of endothelin, through its local and systemic function, as a regulator of vascular tone in normal and pathophysiologic states.

Amino Acid Sequence↗
PubMed1990

Increased endothelin in experimental heart failure.

Recent studies demonstrate that endothelin, a potent endogenous vasoconstrictor peptide, circulates in plasma of normal animals and humans. However, the role of this peptide in pathophysiological states remains unclear. The present study was designed to test the hypothesis that circulating endothelin concentrations are increased in experimental congestive heart failure (CHF), a pathophysiological state characterized by activation of vasoconstrictor mechanisms. In anesthetized dogs with CHF produced by 8 days of rapid ventricular pacing (n = 28), circulating plasma endothelin was increased compared with values for normal controls (n = 28; 20.4 +/- 1.4 versus 9.7 +/- 0.9 pg/ml, respectively; p less than 0.0001). A plasma endothelin level of more than 14.0 was a sensitive and specific indicator of significant CHF. Moreover, within the group with experimental CHF, right atrial pressure and pulmonary capillary wedge pressure correlated independently with circulating endothelin levels. Based on recent studies demonstrating the physiological actions of twofold increases in circulating endothelin, as observed in the present study, a possible role for endothelin in the pathophysiology of CHF is advanced.

Animals↗
PubMed1990

Massive gastric distention in the intubated patient. A marker for a defective airway.

Tracheal intubation is a commonly performed procedure generally associated with a low complication rate. A clinical sign that could lead to early detection of complications could improve management of mechanically ventilated patients. We present two instances of potentially lethal complications that were heralded by the presence of massive gastric distention. This finding should alert physicians that an abnormal communication may exist between the endotracheal tube and the gastrointestinal tract.

Aged↗
PubMed1988

Waterborne typhoid fever in Haifa, Israel: clinical, microbiologic, and therapeutic aspects of a major outbreak.

A major outbreak of waterborne typhoid fever involving 77 verified cases occurred in 1985 in a large suburban area of Haifa, Israel. The authors summarize the clinical, microbiologic, and therapeutic aspects of these patients. Fever, usually higher than 39 degrees C, was the hallmark of the disease. Other manifestations of typhoid, although relatively frequent, are presented as part of a mild nonspecific symptom complex, often found only in the prodromal period. An elevated level of serum glutamic-oxaloacetic transaminase (mean, 81 IU/ml) was the most characteristic laboratory abnormality, occurring in 94% of the patients. Blood cultures were positive in 46 of the 50 patients (92%), and were not affected by prior outpatient antibiotic therapy. The first blood culture was diagnostic in 93% of the cases. Although fever tended to disappear more rapidly among patients receiving ampicillin than among those treated with chloramphenicol, results of therapy were similar in both groups. Nevertheless, the relapse rate of 36% among 25 chloramphenicol-treated patients was significantly higher than the 9% noted among 22 patients treated with ampicillin. Except for one case of hemolytic anemia, serious complications were conspicuously absent, and outcomes were uniformly favorable.

Adolescent↗
PubMed1986

The effect of hyperbaric oxygen on acute experimental sulfide poisoning in the rat.

In order to evaluate the efficiency of hyperbaric oxygen in experimental acute sulfide poisoning, we studied the effect of 1 ATA (atmosphere absolute) oxygen and sodium nitrite therapy. We then studied the effect of oxygen at 3 ATA alone and in combination with intraperitoneal sodium nitrite injection on rats poisoned by intraperitoneal injection of LD75 sulfide. Electroencephalogram and heart rate were continuously monitored. We also studied the effect of sodium nitrite and hyperbaric oxygen administered before the poisoning (protective effect). In our experimental set, death of untreated poisoned animals occurred within 5 min. There is a parallel between modification of the EEG pattern and apnea. Respiratory arrest always preceded cardiac arrest. Pure oxygen (1 ATA O2) is effective in preventing death in experimental sulfide poisoning. 3 ATA oxygen was significantly more effective in preventing death than 1 ATA oxygen, or sodium nitrite alone. The best therapeutic regimen was a combination of 3 ATA oxygen and sodium nitrite administration.

Animals↗
PubMed1981

Phanerozoic cycles of sedimentary carbon and sulfur.

A reservoir model of a Recent steady-state sedimentary system in which the reduced sulfur and oxidized sulfur reservoirs were coupled with the oxidized carbon and reduced carbon reservoirs was constructed. The time curve of the sulfur isotope ratios of the sedimentary sulfate reservoir was used to drive the model back to the beginning of Cambrian time (600 million years ago), producing the reservoir sizes and isotope values and material fluxes of the carbon-sulfur system. The predicted values of carbon isotope ratios of the carbonate reservoir agree well with observed values, showing that the model is basically sound. Some general conclusions from this success are (i) material flux rates in the carbon-oxygen-sulfur system of the geologic past (averaged over tens of millions of years) lie within about a factor of 2 of Recent rates. (ii) The oxidation-reduction balances of Phanerozoic time were dominated by reciprocal relationships between carbon and sulfur compounds. (iii) The rate of production of atmospheric oxygen by storage in sediments of organic carbon of photosynthetic origin increased from the Cambrian Period to the Permian Period and declined somewhat from the Permian Period to the Present. (iv) The storage of oxygen in oxidized sulfur compounds kept pace (within the limits of the data) with oxygen production. (v) Transfer of oxygen from CO(2) to SO(4) from the Cambrian to the Permian Period was several times the Recent free oxygen content of the atmosphere.

Journal Article↗
PubMedDate not supplied

C-type natriuretic peptide immunoreactivity in human breast vascular endothelial cells.

The present study was undertaken to determine the presence of CNP immunoreactivity in human breast tissue (n = 9). Immunohistochemical staining of breast tissue revealed the presence of CNP immunoreactivity localized to vascular endothelial cells. This study demonstrates for the first time that CNP immunoreactivity is present in humans. Based upon the knows biological actions of CNP, these findings suggest that CNP may function as part of an endothelium-derived vasoregulatory system.

Atrial Natriuretic Factor↗
PubMedDate not supplied

The endothelium: dysfunction and beyond.

Since its anatomic discovery in the 19th century, the endothelium was considered to fulfill no other purpose than that of a physical barrier between blood and tissue, until Furchgott and colleagues defined endothelium-dependent vasoreactivity in the late 1970s. Henceforth, a functional paradigm defined the balance between endothelium-derived relaxing factors and endothelium-derived contracting factors as the hallmark of endothelial cell integrity. As a consequence, any reflection of a deviation from this state was defined as endothelial dysfunction, most notably the impairment of vasorelaxation in response to pharmacologic stimuli such as acetylcholine or nonpharmacologic stimuli such as shear stress and cold pressor. Within the coronary artery tree these alterations have been recognized before the development of obstructive coronary artery disease, affecting the microcirculation before the epicardial conduit vessel. Furthermore, recent clinical trials outlined the prognostic significance of these changes, whereby impairment of increase in coronary blood flow in response to endothelium-dependent stimuli seemed to be of utmost importance. Thus it is intriguing to speculate on the evolving role of myocardial perfusion imaging in combination with pharmacologic and nonpharmacologic stimuli for the noninvasive assessment of coronary endothelial dysfunction in patients at risk for future adverse events. At a minimum, this review aims to put endothelial dysfunction into an imaging perspective beyond the scope of the conventional approach.

Animals↗
PubMedDate not supplied

Methylergonovine-induced diffuse coronary spasm in a patient with exercise-induced coronary spasm after heart transplantation.

Coronary artery spasm is a rarely reported condition after heart transplantation. We report a case of exercise-induced coronary artery spasm in a patient 1-year after orthotopic heart transplantation. Serial quantitative coronary angiography showed significant diffuse loss of luminal diameter. Provocative testing with intracoronary acetylcholine and intravenous methylergonovine maleate was performed in an effort to document efficacy of the antispasm regimen. Infusion of acetylcholine into the left anterior descending coronary artery resulted in transient closure of the vessel. Diffuse spasm resulting in hypotension and ventricular fibrillation occurred with intravenous methylergonovine maleate administration. Because of the risk of provoking diffuse spasm, intravenous administration of methylergonovine maleate should be avoided in the posttransplantation setting. Review of the literature suggests that coronary artery spasm after transplantation is often associated with severe transplant coronary artery disease and may be associated with a poor prognosis. Coronary artery spasm may be a more common cause of syncope and death after transplantation than it is currently thought to be.

Acetylcholine↗