Leiomyosarcoma in a domestic ferret: morphologic and immunocytochemical diagnosis.
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Biomedical subjects
S R Brunnert
Publications and source records attributed to S R Brunnert.
Dystrophic cardiac calcinosis in mice: abnormal myocardial response to freeze-thaw injury.
Dystrophic cardiac calcinosis (DCC) is a frequent finding in DBA/2, C3H and BALB/c mice and its etiology is not known. Previous studies have speculated that myocardial necrosis is involved in the pathogenesis of DCC. In this study, cardiac necrosis was induced in DBA/2, C3H and C57BL/6 mice by freeze-thaw injury through the abdominal diaphragm. Four weeks after freeze-thawing, the mice were sacrificed and the hearts and diaphragms were examined. In response to injury, cardiac mineralization was present only in DBA/2 and C3H mice. The myocardium of C57BL/6 mice (control strain) healed by fibrosis without mineralization, the normal response of the myocardium to injury. Calcified diaphragms also were present at the site of freeze-thaw injury in DBA/2 and C3H mice, which is supportive evidence that a systemic abnormality is involved in the pathogenesis of DCC. The conclusion from this study is that the pathogenesis of DCC in DBA/2 and C3H mice is multifactorial and involves both myocardial necrosis and an abnormal response to injury.
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Reversible induction of right ventricular atriopeptin synthesis in hypertrophy due to hypoxia.
Right ventricular hypertrophy produced in rats exposed to 10% oxygen for 3 weeks resulted in a ninefold increase in atriopeptin immunoreactivity (APir) and a 160-fold increase in atriopeptin messenger RNA (AP mRNA) in the right ventricular myocardium. A small but significant increase in left ventricular APir and AP mRNA was also present, probably representing the interventricular septum. Right atrial APir was decreased by 50%, but left atrial APir was not different from normoxic controls. Purification of ventricular tissue extracts by high-performance liquid chromatography revealed primarily the high molecular weight prohormone. The development of right ventricular hypertrophy and right ventricular APir content followed a similar time course, each evident at 7 days of hypoxia and reaching a plateau at 14 days. Hypoxia followed by normoxia caused right ventricular APir to fall to control levels within 3 days, despite persistent right ventricular hypertrophy. This data demonstrates that hypoxia can reversibly induce extra-atrial expression of atriopeptin synthesis in the cardiac ventricle.
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Ventricular atriopeptin. Unmasking of messenger RNA and peptide synthesis by hypertrophy or dexamethasone.
Left ventricular hypertrophy or treatment with dexamethasone caused a 2.5-fold to threefold increase in both immunoreactive atriopeptin (AP) and AP messenger RNA (mRNA), primarily in left ventricular tissue. The combined treatments increased immunoreactive AP and AP mRNA more than either treatment alone. In the animals in which cardiac hypertrophy had been produced by abdominal aortic constriction, there was a decrease in atrial levels of AP and an increase in plasma levels of immunoreactive AP. The increase in left ventricular immunoreactive AP was confirmed by immunohistochemical staining of tissue from hypertrophied and/or dexamethasone-treated rats. The mRNA accumulated in the left ventricle was identical to atrial AP mRNA, as judged by transcriptional start site and by size on Northern blots. Because the mass of ventricular tissue is substantially greater than that of atrial tissue, the induced mRNA levels may represent a total abundance approaching one third of the total AP mRNA in the atria. High performance liquid chromatographic purification of ventricular extracts primarily demonstrated the presence of the high molecular precursor and small amounts of C-terminal peptide AP. Induction of ventricular AP (mRNA and peptide) may represent regression of the tissue to an earlier developmental form. These data provide a unique example of regulation of AP biosynthesis in nonatrial tissue.
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Inflammatory cytokines in a murine model of infection-induced preterm labor: cause or effect?
OBJECTIVE: To characterize the expression of inflammatory cytokines in a murine model of preterm delivery induced by heat-killed bacteria. METHODS: The right uterine horns of female CD-1 mice on day 14.5 of 19-20 days of gestation were inoculated with either sterile media or killed Escherichia coli bacteria (10(5)-10(10) organisms per mouse). The incidence of preterm delivery was recorded. The concentrations of cytokines (interleukin [IL-] 1 alpha, IL-1 beta, IL-1 receptor antagonist [IL-1ra], IL-6, and tumor necrosis factor alpha [TNF alpha]) within maternal and fetal tissue homogenates were determined by enzyme-linked immunosorbent assay at various times after inoculation. RESULTS: Killed E. coli induced preterm delivery in a dose-dependent fashion. Inoculation with 10(10) bacteria (sufficient to cause delivery in all mice) produced increases in IL-1 alpha, IL-1 beta, IL-6, and TNF alpha within uteri and fetal membranes, but not within placentas, fetal bodies, and maternal serum. Maximum mean uterine levels of IL-1 and IL-6 exceeded those of fetal tissues (membranes, placentas, and fetal bodies) by greater than 15-fold. Maximal uterine IL-1 and TNF alpha levels following inoculation with 10(10) bacteria exceeded those that followed inoculation with 10(7) bacteria (below the threshold for delivery) by 2.5- to 5-fold. The anti-inflammatory cytokine IL-1ra was expressed in higher concentrations in fetal than in maternal tissues and was unaltered by the bacterial inoculum. CONCLUSIONS: E. coli induce labor in mice even in the absence of bacterial viability. Although IL-1 and TNF alpha were upregulated by bacterial inocula causing delivery, peak levels were only 2.5- to 5-fold higher than those that occurred with inocula below the threshold for delivery (1000-fold fewer bacteria). Whether IL-1 and TNF alpha mediate labor during in vivo infection, or whether the upregulation of these cytokines merely represents an epiphenomenon accompanying infection, remains unknown.
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