Vertebrate phylogeny of hydrogen sulfide vasoactivity.

Hydrogen sulfide (H(2)S) is a recently identified endogenous vasodilator in mammals. In steelhead/rainbow trout (Oncorhynchus mykiss, Osteichthyes), H(2)S produces both dose-dependent dilation and a unique dose-dependent constriction. In this study, we examined H(2)S vasoactivity in all vertebrate classes to determine whether H(2)S is universally vasoactive and to identify phylogenetic and/or environmental trends.

Pregnancy-related maternal deaths.

Pregnancy is a normal biologic process, but because of a variety of physiologic factors, it increases a woman's risk for death. Maternal deaths in pregnancy may be due to conditions unique to pregnancy, conditions associated with pregnancy, or conditions unrelated to but exacerbated by pregnancy. Death may occur during any trimester, during labor/birth, or postpartum.

Vascular anatomy of the gills in a high energy demand teleost, the skipjack tuna (Katsuwonus pelamis).

Tunas (family: Scombridae, Tribe: Thunnini) exhibit anatomical, physiological, and biochemical adaptations that dramatically increase the ability of their cardiorespiratory systems to transfer oxygen from the water to the tissues. In the present study the vascular anatomy of the skipjack tuna, Katsuwonus pelamis, gill was examined by light and scanning electron microscopic analysis of methyl methacrylate vascular corrosion replicas prepared under physiological pressure. The gill filament contains three distinct blood pathways, respiratory, interlamellar, and nutrient.

Transvascular and intravascular fluid transport in the rainbow trout: revisiting Starling's forces, the secondary circulation and interstitial compliance.

The kinetics of transvascular fluid transport across fish capillaries and redistribution of fluids between intravascular compartments in intact fish are unknown. Cannulae were placed in the dorsal aorta (DA) and caudal vein (CV) of rainbow trout Oncorhynchus mykiss (mass 0.45-0.

Gill circulation: regulation of perfusion distribution and metabolism of regulatory molecules.

The fish gill is the primary regulatory interface between internal and external milieu and a variety of neurocrine, endocrine, paracrine, and autocrine signals coordinate and control gill functions. Many of these messengers also affect gill vascular resistance, and they, in turn, may be inactivated (or activated) by branchial vessels. Few studies have critically addressed how flow is distributed within the gill filament, the physiological consequences thereof, or the impact of gill hormone metabolism on gill and systemic homeostasis.

Vascular anatomy of the fish gill.

The fish gill is the most physiologically diversified vertebrate organ, and its vasculature the most intricate. Application of vascular corrosion techniques that couple high-fidelity resins, such as methyl methacrylate, with scanning electron microscopy yields three-dimensional replicas of the microcirculation that have fostered a better appreciate gill perfusion pathways. This is the focus of the present review.

Accidental sharp force injury fatalities.

The authors review all accidental sharp force injury deaths investigated at the Southwestern Institute of Forensic Sciences from 1990 to 1999. Twenty-two cases of accidental sharp force injury were identified, accounting for 0.29% of all accidental deaths (9,562) during the 10-year study period.

Uterine epithelial-sperm interaction, endometrial cycle and sperm storage in the terminal zone of the oviducal gland in the placental smoothhound, Mustelus canis.

The fate of spermatozoa deposited within the female reproductive tract has been described in the smoothhound, Mustelus canis. Evidence of uterine epithelial-sperm interaction is presented, as well as documentation of sperm storage specifically in the terminal zone of the oviducal gland. Sperm fate is correlated with morphology of the endometrial cycle and specificity of storage in the oviducal gland.

Ultrastructure of sperm storage and male genital ducts in a male holocephalan, the elephant fish, Callorhynchus milii.

In chondrichthyes, the process of spermatogenesis produces a spermatocyst composed of Sertoli cells and their cohort of associated spermatozoa linearly arrayed and embedded in the apical end of the Sertoli cell. The extratesticular ducts consist of paired epididymis, ductus deferens, isthmus, and seminal vesicles. In transit through the ducts, spermatozoa undergo modification by secretions of the extratesticular ducts and associated glands, i.

Intracellular and extracellular calcium utilization during hypoxic vasoconstriction of cyclostome aortas.

Hypoxic vasoconstriction (HV) is an intrinsic response of mammalian pulmonary and cyclostome aortic vascular smooth muscle. The present study examined the utilization of calcium during HV in dorsal aortas (DA) from sea lamprey and New Zealand hagfish. HV was temporally correlated with increased free cytosolic calcium (Ca2+c) in lamprey DA.

Hormone metabolism by the fish gill.

The fish gill, like the mammalian lung, is ideally situated to process circulating biomolecules because: 1) the gill is the only organ perfused by the entire cardiac output, 2) the in-series positioning of branchial and systemic circulations permits "conditioning" of blood immediately before systemic perfusion and 3) gill microcirculation is extensive, providing substantial endothelial/pillar cell surface in contact with plasma. In addition, two or three distinct circulatory pathways within the gill may differentially affect plasma substrates, raising the possibility of vasoactive control of hormone titers. Hormones may be activated or inactivated by the gill, the latter involving extraction (uptake) from the plasma, metabolism by enzymes on the endothelial surface without uptake or uptake plus intracellular metabolism.

Angiotensin signaling and receptor types in teleost fish.

Despite advances characterizing mammalian angiotensin receptors, the phylogeny of fish angiotensin receptors remains unclear. Three aspects of receptor function: (1) the nature of the ligand; (2) the second messenger system activated by it; and (3) the pharmacological profile of specific antagonists, are examined to provide insight into the fish receptor. (1) The octapeptide sequences of fish and mammalian angiotensin II (ANG II) are nearly homologous, differing only at the first and fifth residues.

Hypoxic vasoconstriction of cyclostome systemic vessels: the antecedent of hypoxic pulmonary vasoconstriction?

Hypoxic vasoconstriction (HV) is an intrinsic response of mammalian pulmonary vascular smooth muscle (VSM). In the present study, HV was examined by myography of vessel rings from three primitive vertebrates: New Zealand hagfish (NZH), Pacific hagfish (PH), and sea lamprey (SL). Hypoxia dilated pre-gill arteries (ventral aorta, afferent branchial) from all species, whereas it contracted systemic arteries [dorsal aorta (DA), efferent branchial, celiacomesenteric].

Guanine nucleotide transport by atractyloside-sensitive and -insensitive carriers in isolated heart mitochondria.

In previous work (McKee EE, Bentley AT, Smith RM Jr, and Ciaccio CE, Biochem Biophys Res Commun 257: 466-472, 1999), the transport of guanine nucleotides into the matrix of intact isolated heart mitochondria was demonstrated. In this study, the time course and mechanisms of guanine nucleotide transport are characterized. Two distinct mechanisms of transport were found to be capable of moving guanine nucleotides across the inner membrane.

Spontaneous contractions in elasmobranch vessels in vitro.

Isolated vessels from four elasmobranchs, yellow stingray (Urolophus jamaicensis), clearnose skate (Raja eglanteria), ghost shark (Hydrolagus novaezelandiae), and spiny dogfish (Squalus acanthias), were examined for the presence of spontaneous contractions (SC). SC were observed in otherwise unstimulated dorsal aortas (DA) from stingray and ghost shark, but not in skate DA. Unstimulated ventral aortas (VA) did not exhibit SC.

Effects of endothelin-1 and homologous trout endothelin on cardiovascular function in rainbow trout.

The cardiovascular effects of endothelin (ET)-1 and the recently sequenced homologous trout ET were examined in unanesthetized trout, and vascular capacitance curves were constructed to evaluate the responsiveness of the venous system to ET-1. A bolus dose of 667 pmol/kg ET-1 doubled ventral aortic pressure; produced a triphasic pressor-depressor-pressor response in dorsal aortic pressure (P(DA)); increased central venous pressure, gill resistance, and systemic resistance; and decreased cardiac output, heart rate, and stroke volume. These responses were dose dependent.

The control of blood pressure during external hypercapnia in the rainbow trout (Oncorhynchus mykiss).

Adult freshwater rainbow trout (Oncorhynchus mykiss) were exposed acutely (approximately 20 min) in a stepwise manner to increasing levels of environmental carbon dioxide ranging between 1.7 and 9.0 mmHg (0.

Ultrastructural analysis of folliculogenesis in the ovary of the yellow spotted stingray, Urolophus jamaicensis.

The ovary of the yellow spotted ray, Urolophus jamaicensis, is embedded in the epigonal gland, a lymphomyeloid organ. The covering of the ovary is composed of a germinal epithelium that is cuboidal and dome-shaped with microvilli. Adjacent cells have elaborate intercellular folds that create dilated intercellular spaces.

Origin of guanine nucleotides in isolated heart mitochondria.

Presence of guanine nucleotide within the matrix of mitochondria is uncontested; the mechanism by which GTP takes up residence in the matrix is unknown. In this report, we demonstrate for the first time that direct transport of guanine nucleotide across the inner membrane of heart mitochondria is possible. Transport of guanine nucleotides from the medium to the matrix was suggested by inhibition of translation in isolated rat heart mitochondria when GTP-gamma-S was added to the medium.

Pharmacological characterization of arginine vasotocin vascular smooth muscle receptors in the trout (Oncorhynchus mykiss) in vitro.

Arginine vasotocin (AVT) is present in the neurohypophysis of all nonmammalian vertebrates and it appears to be the antecedent of the neurohypophysial nonapeptide hormones. Relatively little is known about AVT receptors in lower vertebrates, especially fish, and the present study was designed to examine AVT receptor interactions in trout vascular and nonvascular smooth muscle in vitro. AVT produced dose-dependent contraction of isolated rings from celiacomesenteric, coronary, and efferent branchial arteries, ventral aorta, anterior cardinal vein, and strips of ductus Cuvier.

Sperm aggregations in the spermatheca of female desmognathine salamanders (Amphibia: Urodela: Plethodontidae).

The alignment of sperm in a cloacal sperm storage gland, the spermatheca, was studied in female desmognathine salamanders by scanning and transmission electron microscopy. Females representing nine species and collected in spring, late summer, and fall in the southern Appalachian Mountains contained abundant sperm in their spermathecae. The spermatheca is a compound tubuloalveolar gland connected by a single common tube to the middorsal wall of the cloaca.

Catecholaminergic regulation of venous function in the rainbow trout.

The significance of the sympathetic nervous system (SNS) in regulating peripheral vascular resistance and cardiac function in fish has been well established, whereas its effect on venous function in vivo is unknown. Two protocols were employed in the present study to evaluate SNS effects on the venous system in intact, unanesthetized trout. In the first, trout were instrumented with pressure cannulas in the ventral (PVA) and dorsal (PDA) aortas and ductus Cuvier (PVEN), and cardiac output (CO) was measured with a flow probe around the ventral aorta.

Effects of natriuretic peptides and nitroprusside on venous function in trout.

Active venous regulation of cardiovascular function is well known in mammals but has not been demonstrated in fish. In the present studies, the natriuretic peptides (NP) rat atrial natriuretic peptide (ANP) and trout ventricular natriuretic peptide (VNP), clearance receptor inhibitor SC-46542, and sodium nitroprusside (SNP) were infused into unanesthetized trout fitted with pressure cannulas in the ventral aorta, dorsal aorta, and ductus Cuvier, and a ventral aorta (VA) flow probe was used to measure cardiac output (CO). In another group, in vivo vascular (venous) capacitance curves were obtained during ANP or SNP infusion.

Cardiovascular effects of homologous bradykinin in rainbow trout.

Bradykinins have only recently been identified in fish, and a detailed analysis of their cardiovascular actions is lacking. The present study examines the cardiovascular effects of trout bradykinin ([Arg0,Trp5,Leu8]bradykinin; tBK) in conscious trout, Oncorhynchus mykiss. tBK (1-10 nmol/kg body wt bolus) produced triphasic pressor-depressor-pressor responses.

Topical substance P and corneal epithelial wound closure in the rabbit.

Purpose: The authors determined the effect of topically applied substance P (SP) on the rate of corneal epithelial wound closure in the rabbit.

Methods: Uniform circular lesions, 6.5 mm in diameter, were made bilaterally in the corneal epithelium of 24 rabbits using N-heptanol.