The Renin-Angiotensin-Aldosterone System in Greyhounds and Non-Greyhound Dogs.

Background: The renin-angiotensin-aldosterone system (RAAS) regulates blood pressure, electrolyte homeostasis, and renal function. Blood pressure, serum sodium concentrations, and urinary albumin excretion are higher in Greyhounds than other purebred and mixed-breed dogs.

Hypothesis: Alterations in the RAAS in Greyhounds are associated with hemodynamic and clinicopathologic differences observed in the breed.

Plasma Vasoprotective Eicosanoid Concentrations in Healthy Greyhounds and Non-Greyhound Dogs.

Background: Hypertension and albuminuria often coexist in Greyhounds, suggesting generalized vascular dysfunction that could contribute to the development of a variety of diseases in this breed. Eicosanoid metabolites of arachidonic acid (AA) mediate endothelial function, vascular reactivity, and proteinuria in humans and in rodent models.

Hypothesis: The eicosanoid profile of Greyhounds is shifted toward metabolites that promote vascular dysfunction, hypertension, and proteinuria.

Salt-induced cardiac hypertrophy is independent of blood pressure and endothelin in obese, heart failure-prone SHHF rats.

The interaction of salt sensitivity and obesity in development of cardiac hypertrophy is incompletely understood. The SHHF/Mcc-fa(cp) (SHHF) rat model was used to examine the effect of high salt on cardiac hypertrophy and expression of endothelin (ET) and nitric oxide synthase (NOS) isoforms. Homozygous lean (+/+) and obese (fa(cp)/fa(cp)) SHHF were fed a low-salt diet (0.

Adoptive transfer of splenocytes in SCID mice implicates CD4+ T cells in apoptosis and epithelial proliferation associated with Helicobacter pylori-induced gastritis.

Helicobacter pylori causes severe, rapidly progressive gastritis in severe combined immunodeficient (SCID) mouse recipients of congenic splenocytes. The H. pylori-infected and uninfected C57BL/6J and recipient SCID mice were evaluated to detect CD4+ and CD8+ T cells, B cells, apoptotic epithelial cells, and epithelial cell proliferation at postinoculation weeks 5, 6, 8, and 12.

Increased salt sensitivity secondary to leptin resistance in SHHF rats is mediated by endothelin.

A link between leptin resistance, obesity, and salt sensitivity has been suggested. SHHF/Mcc-fa(cp) rats (SHHF) were used to study the effect of gene dosage of a null mutation of the leptin receptor (cp) on salt sensitivity and response to a combined endothelin A and B receptor antagonist (bosentan). Obese (cp/cp), heterozygous (+/cp), and homozygous lean (+/+) male SHHF were fed a low salt diet (0.

flaA mRNA transcription level correlates with Helicobacter pylori colonisation efficiency in gnotobiotic piglets.

In-vivo passage of the gastric pathogen Helicobacter pylori in gnotobiotic piglets results in a greater colonisation efficiency in subsequent infections. The rate of colonisation steadily increases with the number of passages. To determine if this increased efficiency is related to the level of expression of flaA, a gene which encodes the major subunit of flagella, this study evaluated the level of flaA expression at five points during serial in-vivo passage of strain 26695.

Effect of ovariectomy and estrogen replacement on cardiovascular disease in heart failure-prone SHHF/Mcc- fa cp rats.

The importance of endogenous and exogenous estrogen levels to the development of cardiovascular disease in women in controversial. The purpose of our study was to examine the effect of estrogen on the development of hypertension, cardiac hypertrophy, ventricular function, and gene expression for atrial natriuretic peptide (ANP) and components of the renin angiotensin system in spontaneously hypertensive heart failure rats (SHHF/Mcc- facp). Development of hypertension was prevented in 3-month-old ovariectomized rats receiving subcutaneous 17 beta -estradiol implants (EST) compared to ovariectomized (OVX) and controls (CON).

Comparison of verapamil and felodipine treatment on lipid and glucose metabolism in obese female SHHF/Mcc-facp rats.

Calcium channel blockers, verapamil or felodipine, were given to genetically obese 6 and 11-month-old female SHHF/Mcc-facp (SHHF: Spontaneous Hypertension Heart Failure) rats for 8 weeks to investigate their effects on glucose and lipid metabolism and obesity. Both antihypertensive agents significantly decreased systolic blood pressure. In 11-month-old rats, verapamil treatment significantly decreased body weight after 4 weeks whereas with felodipine it was only significantly reduced after 8 weeks.

Verapamil accelerates the transition to heart failure in obese, hypertensive, female SHHF/Mcc-fa(cp) rats.

We sought to characterize the effects of the nonselective Ca2+ channel antagonist, verapamil, and the vascular-selective Ca2+ channel antagonist, felodipine, on obese, hypertensive, heart failure-prone, female SHHF/Mcc-fa(cp) rats. Rats were treated for < or = 2 months with verapamil (57 mg/kg/day) or felodipine (24 mg/kg/day). Blood pressures were determined at monthly intervals by the tail-cuff method.

Renal function and organic anion and cation transport during dehydration and/or food restriction in chickens.

The effect of dehydration in the presence or absence of continued food intake on renal function was evaluated in chickens. In addition, renal transport of organic anions and cations under these conditions was assessed in vitro by uptake of 14C-para-aminohippuric acid and 14C-tetraethylammonium bromide by renal slices. Water restriction with continued food intake resulted in increases in serum osmolality and serum concentrations of sodium, uric acid, calcium and total protein.

Acute renal failure as the cause of death in chickens following intravenous inoculation with avian influenza virus A/chicken/Alabama/7395/75 (H4N8).

One-day-old and 5-week-old commercial leghorn, specific-pathogen-free leghorn, and broiler chickens were inoculated intravenously with either avian influenza virus isolate A/chicken/Alabama/7395/75 (H4N8) (Ck/AL) or sterile diluent. Ck/AL infection resulted in a 44% mortality rate, reduced weight gains, and necrosis of proximal renal tubules and/or tubulointerstitial nephritis. The renal tubule necrosis was more severe and widespread in chickens that died than in chickens that were euthanatized.

Use of a single injection solute-clearance method for determination of glomerular filtration rate and effective renal plasma flow in chickens.

A single-injection clearance method for determining glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) in chickens was compared with the continuous-infusion method. Male and female White Leghorn chickens were anesthetized, and catheters were placed in both brachial veins and over both ureteral openings. A single-bolus injection of 3H-inulin and 14C-para-aminohippuric acid was given at a dose of 1.

Treatment of obese female and male SHHF/Mcc-fa(cp) rats with antihypertensive drugs, nifedipine and enalapril: effects on body weight, fat distribution, insulin resistance and systolic pressure.

Little is known about the effects of common antihypertensive drugs in obese, insulin-resistant females. Nine-month-old obese female SHHF/Mcc-fa(cp) rats that received either nifedipine, a calcium channel antagonist, or enalapril, an angiotensin-converting-enzyme inhibitor, for three months were compared with untreated SHHF/Mcc-fa(cp) rats (controls). After one month, nifedipine significantly decreased body weight in obese females compared to either enalapril or controls.

The effect of antecedent influenza A virus infection on the adherence of Hemophilus influenzae to chinchilla tracheal epithelium.

The adherence of Hemophilus influenzae (type b and nontypable) to ciliated chinchilla respiratory epithelium was investigated using a whole organ perfusion technique. Nontypable H influenzae (NTHi) were shown to be more adherent than type b to these organized and differentiated tracheal organ cultures. Bacteria were found adhering to ciliated cells.

Frequency of fimbriation of nontypable Haemophilus influenzae and its ability to adhere to chinchilla and human respiratory epithelium.

To date, we have examined nearly 60 clinical isolates of nontypable Haemophilus influenzae (26 nasopharyngeal, 33 from middle ear effusions) and have found that 100% were fimbriated. The percentage of cells bearing fimbriae within each isolate varied from less than 10 to 100%, with fimbriae being either peritrichous or bipolar in distribution. Fimbriae were approximately 2.