Effects of changes in loading conditions and heart rate on the myocardial performance index in cats

OBJECTIVE: To evaluate the effect of changes in hemodynamics on the myocardial performance index (MPI) in cats. ANIMALS: 6 mixed-breed cats. PROCEDURES: Cats were anesthetized by administration of thiopental sodium; anesthesia was maintained by administration of isoflurane. Systolic arterial pressure and central venous pressure were measured by use of catheters, and heart rate was controlled by right atrial pacing. Afterload was increased by balloon occlusion of the descending aorta, and preload was increased by IV infusion of lactated Ringer's solution at a rate of 40 mL/kg/h. Echocardiography was performed for each condition. RESULTS: Atrial pacing significantly increased heart rate. The MPI did not change with heart rate. Arterial pressure and MPI increased significantly during aortic occlusion. The IV infusion increased fractional shortening but did not change the MPI. Multiple regression analysis revealed that the MPI was not affected by heart rate, systolic arterial pressure, central venous pressure, fractional shortening, or velocity of the E wave. CONCLUSIONS AND CLINICAL RELEVANCE: The MPI can be used to assess cardiac function in healthy cats. The MPI is independent of heart rate and systolic arterial pressure but is sensitive to changes in afterload.     

The genetic diversities of 4 species of subg. Lithocerasus (Prunus, Rosaceae) revealed by RAPD analysis

RAPD analysis was applied to reveal the genetic diversities of 4 speciesof subg. Lithocerasus within the genus Prunus using 40accessions representing the subgenera Prunophora, Amygdalus,Lithocerasus and Cerasus. The accession of subg. Lithocerasus are phenotypically similar to members of subgenus Cerasus but different with them in interspecific crossing tests and isozymeprofiles. Two major clusters, `Prunophora and Amygdalus group' and `Cerasus group' were constructed in the phenogram. We revealthat the examined 4 species of subg. Lithocerasus species; P.tomentosa Thunb., P. japonica Thunb., P. glandulosa Thunb.and P. besseyi Bailey, were genetically closer to the members ofsubgenera Prunophora and Amygdalus than to subg. Cerasus.     

Vertical Distribution of Trace Metals in Natural Soil Horizons from Japan Part 2: Effects of Organic Components in Soil

The association of Al, Mn, Fe, Ba, Zn, Cr, Ni, Co and Pb withsoil organic matter (SOM) was investigated in three Japanesesoils. Organically bound metals were assayed by elementalanalysis of a fraction extracted with acidified hydrogenperoxide (H₂O₂) and the humic acid extracted withalkaline reagent, from soil sampled at various depths of solums.A Dystric Cambisol showed higher extractability with acidifiedH₂O₂ for most of the metals than a Humic Andosol and an Orthic Acrisol. A Humic Andosol had more metals associated with humicacid than the other two soils.Cu showed high extractability with acidified H₂O₂ andalso significant association with humic acid, while Pb showedhigh extractability with acidified H₂O₂ but itsassociation with humic acid was relatively low among the metalsinvestigated. As humic acid is highly resistant to weathering,retention of Cu with SOM may last longer than that of Pb.The binding of metals with SOM probably has contributed to theaccumulation of some metals in organic-rich shallow horizons of soil. Such metals were Zn, Cu, Ni and Pb in a Dystric Cambisol,Cu in a Humic Andosol, and Pb and Cu in an Orthic Arisol.     

A novel genetic marker to differentiate feline herpesvirus type 1 field isolates

Five recent field isolates of feline herpesvirus type 1 (FHV-1) were compared by digestion with a restriction endonuclease, SalI or MluI. The SalI digestion showed a potentially useful difference in one isolate 00-035 that had an approximately 3.0 kbp fragment instead of a 2.6 kbp fragment in the other strains. After cloning the 3.0 and 2.6 kbp fragments, the nucleotide sequences were analyzed. The result showed that the 3.0 kbp fragment of 00-035 included a complete open reading frame of the herpes simplex virus 1 (HSV-1) homologue of the UL17 gene and a 5'-part of UL16 gene and that only one nucleotide substitution was found in the 5'-region of UL17 gene where the SalI site of the 2.6 kbp fragment locates. Based on these nucleotide sequences, two PCR primers were designed to amplify the region around the SalI site in the UL17 gene and the PCR was carried out using 78 field isolates from various parts of Japan. The SalI digestion of the PCR products revealed an interesting profile in that the genotype without the SalI site in UL17 gene was dominant in Tottori and Yamagata prefectures (69% and 75%, respectively) but minor in the other regions of Japan (0-10%). These results suggest that the SalI digestion method described in the present study can be used as a genetic marker to differentiate some FHV-1 field isolates and this is the first report that showed different distributions of FHV-1 genotypes using the novel genetic marker.     

Microconidia act the role as spermatia in the sexual reproduction of <Emphasis Type="Italic">Botrytis cinerea</Emphasis>

In the sexual reproductive cycle of Botrytis cinerea, large numbers of microconidia were observed in all the crosses that formed sexual bodies. To clarify the role of the microconidia in sexual reproduction, they were separated using a sucrose density gradient and then used in crossing tests with fungal sclerotia. Sexual bodies were formed in all the crosses in the five mating combinations, demonstrating that microconidia are able to function as spermatia during sexual reproduction of B. cinerea.     

Cloning of bovine MAIL and its mRNA expression in white blood cells of Holstein cows

Molecule possessing ankyrin-repeats induced by lipopolysaccharide (MAIL) is known as an IkappaB protein induced after administration of bacterial lipopolysaccharide (LPS) to mice. In the present study, we cloned bovine MAIL cDNA and examined its mRNA expression in white blood cells isolated from Holstein cows. Bovine MAIL had more than 80% amino acid identities with murine and human MAILs, highly conserved ankyrin-repeat motifs and PEST-like sequences. Bovine MAIL mRNA was undetectable in isolated peripheral white blood cells, but rapidly induced (<1h) after stimulation by LPS and lipid A in vitro in a dose-dependent manner. The lipid A-induced MAIL mRNA expression was found in polymorphonuclear cells, monocytes/macrophages and total lymphocytes, but not in T-lymphocytes. MAIL mRNA was also induced in vivo in peripheral blood leukocytes of cows after intramammary injection of Escherichia coli derived from coliform mastitis. Thus, bovine MAIL, as rodent MAILs, is induced by inflammatory stimuli in specific immune cells in vitro and in vivo, suggesting a role in inflammatory responses to bacterial infection in cattle.     

Cardiovascular effects of a phosphodiesterase III inhibitor in the presence of carvedilol in dogs

The aim of this study was to determine whether dobutamine, dopamine, or milrinone (a phosphodiesterase [PDE] III inhibitor) would support cardiac function that had been attenuated by administration of the beta-blocker, carvedilol (0.2, 0.4, or 0.8 mg/kg). Hemodynamic and cardiac parameters including the heart rate (HR), left-ventricular fractional shortening (FS), and arterial pressure were measured in six healthy dogs without cardiac disease. Carvedilol did not affect FS or arterial pressure, but decreased the HR significantly. The positive inotropic and chronotropic responses to dobutamine and dopamine were attenuated by carvedilol, whereas arterial pressure was unaffected. Milrinone did not affect the HR and decreased arterial pressure, whereas FS was significantly greater both in the control and carvedilol-treated groups. Although milrinone affect the negative chronotropic effects of carvedilol, milrinone increased FS and prevented the decrease in arterial pressure. These results suggest that inhibition of PDE III preserves cardiac contractility and hemodynamic function in the presence of carvedilol.     

Plasma adrenomedullin concentration in dogs with myxomatous mitral valvular disease

Adrenomedullin (AM), a peptide identified to have vasodilating and natriuretic effects, is involved in the regulation of the cardiovascular system. To evaluate plasma AM concentration in dogs with myxomatous mitral valvular disease (MMVD), and to investigate the associations between the concentrations of plasma AM and natriuretic peptides and the echocardiographic data, we evaluated plasma AM concentrations in 31 healthy control dogs and 57 dogs with MMVD. Plasma AM concentrations in dogs with MMVD were higher than that in the control subjects. The plasma AM concentration increased in conjunction with the severity of heart failure according to the International Small Animal Cardiac Health Council (ISACHC). The AM concentrations were 25.1 ± 5.0 fmol/ml (ISACHC class Ia), 29.9 ± 11.0 fmol/ml (ISACHC class Ib), 43.4 ± 19.8 fmol/ml (ISACHC class II) and 73.5 ± 21.7 fmol/ml (ISACHC class III) and 7.5 ± 5.1 fmol/ml (control group), respectively. The receiver operating characteristic curve indicated an area of 0.93 (95% CI, 0.8801-0.9889; <0.0001), a cutoff value of 30.5 fmol/ml, a sensitivity of 87.1%, and a specificity of 82.5% for the determination of congestive heart failure. Plasma AM concentrations correlated with atrial natriuretic peptide concentrations, LA/Ao ratio, and left ventricular diameter. In conclusion, AM may be a potential diagnostic marker for canine MMVD and possibly plays a pathophysiological role in collaboration with the other neurohumoral factors such as natriuretic peptides.     

Regulation of root-to-leaf Na and Cl transport and its association with photosynthetic activity in salt-tolerant soybean genotypes

ABSTRACT

Soil salinity is a major constraint to sustainable crop production. Genetic improvements are needed for growing soybean in salinity-prone environments. Salt-tolerant soybean genotypes alleviate a reduction in photosynthesis and growth under saline conditions; however, the detailed mechanisms involved remain unclear. Here, we aimed to clarify how Na and Cl root-to-leaf transport is quantitatively regulated, and to identify whether photosynthetic tolerance depends on traits associated with either stomata or with mesophyll tissues. Two pairs of pot-grown soybean near-isogenic lines (NILs) consisting of tolerant and susceptible counterparts, derived from a cross between salt-tolerant FT-Abyara and salt-sensitive C01, were subjected to salinity treatment in a rainout greenhouse. Comparison of photosynthetic responses between genotypes indicated that genotypic differences in salinity tolerance depended on the ability for sustained CO₂ assimilation in mesophyll tissues, rather than stomatal conductance. The ratio of photosynthetic rate to intercellular CO₂ concentration (A/Ci) declined exponentially with increasing Na and Cl concentration regardless of genotype, but tolerant genotypes effectively kept both elements at significantly low levels. Under saline conditions, tolerant genotypes reduced Na and Cl content at the two transport pathways: from root to stem, and from stem to leaf, but the reduction of Cl at each pathway was only minor. These results suggest that integrating genetic capacity for Cl transport regulation and osmotic adjustment should be an important target in salinity-tolerance soybean breeding.     

Etiologic study of upper respiratory infections of household dogs

Infectious tracheobronchitis (ITB), also known as the kennel cough, is a respiratory syndrome of dogs and usually appears to be contagious among dogs housed in groups. Etiologic agent of ITB is multiple and sometimes complex. In the present study, 68 household dogs showing clinical signs of respiratory infection were examined, and 20 dogs (29.4%) were found to be positive for either of following agents. Bordetella bronchiseptica (B.b.) was most frequently detected from nasal and oropharynx sites of 7 dogs (10.3%). Among the viruses examined, canine parainfluenza virus (CPIV) was detected with the highest frequency (7.4%). Other pathogens included in the order of frequency group 1 canine coronavirus (4.4%), canine adenovirus type 2 (2.9%), group 2 canine respiratory coronavirus (1.5%), and canine distemper virus (1.5%). Only 2 cases showed mixed infections. Neither influenza A virus nor canine bocavirus (minute virus of canines) was found in any dogs examined. These results indicate that both B.b. and CPIV are likely to be the principal etiologic agents of canine ITB in Japan, and they may be considered as the target for prophylaxis by vaccination.