Model Study of Vector-Loop Morphology During Electrical Mapping of Microscopic Conduction in Cardiac Tissue

Daunomycin, an antibiotic used in the clinical management of acute leukemia, produces a delayed, lethal cardiac toxicity. The lethality is dose and schedule dependent; histopathologic changes induced by the drug have been described in heart, lung, and kidney from hamsters in both single and multiple dose studies. Mice given a single intravenous dose of daunomycin (10 mg/kg) die 6-7 days later. Drug distribution studies indicate that the rodents excrete most of a single dose of the drug as daunomycin and metabolite within 48 hours after dosage (M. A. Asbell, personal communication).Myocardium from the ventricles of 6 moribund BDF1 mice which had received a single intravenous dose of daunomycin (10 mg/kg), and from controls dosed with physiologic saline, was fixed in glutaraldehyde and prepared for electron microscopy.

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Iron storage sites in the myocardium as revealed by cytohistochemistry

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104030 ◽

1988 ◽

Vol 46 ◽

pp. 394-395

Author(s):

M. Ashraf ◽

F. Thompson ◽

S. Miki ◽

P. Srivastava

Keyword(s):

Cardiac Tissue ◽

Coronary Perfusion ◽

Intracellular Iron ◽

Ether Anesthesia ◽

Intense Staining ◽

Iron Storage ◽

Thin Sections ◽

Rat Hearts ◽

Cacodylate Buffer ◽

Made In

Iron is believed to play an important role in the pathogenesis of ischemic injury. However, the sources of intracellular iron in myocytes are not yet defined. In this study we have attempted to localize iron at various cellular sites of the cardiac tissue with the ferrocyanide technique.Rat hearts were excised under ether anesthesia. They were fixed with coronary perfusion with 3% buffered glutaraldehyde made in 0.1 M cacodylate buffer pH 7.3. Sections, 60 μm in thickness, were cut on a vibratome and were incubated in the medium containing 500 mg of potassium ferrocyanide in 49.5 ml H2O and 0.5 ml concentrated HC1 for 30 minutes at room temperature. Following rinses in the buffer, tissues were dehydrated in ethanol and embedded in Spurr medium.The examination of thin sections revealed intense staining or reaction product in peroxisomes (Fig. 1).

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Immunoelectron microscope detection of C-type natriuretic peptide in normal human atrial tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100147776 ◽

1993 ◽

Vol 51 ◽

pp. 388-389

Author(s):

Chi-Ming Wei ◽

Margaret Hukee ◽

Christopher G.A. McGregor ◽

John C. Burnett

Keyword(s):

Amino Acid ◽

Natriuretic Peptide ◽

Vascular Tone ◽

Cardiac Tissue ◽

Ring Structure ◽

Terminal Amino Acid ◽

Amino Acid Peptide ◽

Normal Human ◽

Terminal Amino ◽

The Brain

C-type natriuretic peptide (CNP) is a newly identified peptide that is structurally related to atrial (ANP) and brain natriuretic peptide (BNP). CNP exists as a 22-amino acid peptide and like ANP and BNP has a 17-amino acid ring formed by a disulfide bond. Unlike these two previously identified cardiac peptides, CNP lacks the COOH-terminal amino acid extension from the ring structure. ANP, BNP and CNP decrease cardiac preload, but unlike ANP and BNP, CNP is not natriuretic. While ANP and BNP have been localized to the heart, recent investigations have failed to detect CNP mRNA in the myocardium although small concentrations of CNP are detectable in the porcine myocardium. While originally localized to the brain, recent investigations have localized CNP to endothelial cells consistent with a paracrine role for CNP in the control of vascular tone. While CNP has been detected in cardiac tissue by radioimmunoassay, no studies have demonstrated CNP localization in normal human heart by immunoelectron microscopy.

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