Pharmacokinetic evaluation of a sustained-release compounded procainamide preparation after 24-h (acute) administration in normal dogs.

INTRODUCTION: The objective of the present study was to evaluate the pharmacokinetics of a compounded sustained-release procainamide formulation in normal dogs. ANIMALS: Six healthy, purpose-bred mixed-breed dogs participated in the study. METHODS: In phase I, two dogs were administered oral procainamide (30 mg/kg), and plasma was obtained to determine plasma concentration ranges and duration. In phase II, six dogs were administered procainamide (30 mg/kg by mouth every 12 hours) to determine the pharmacokinetics of sustained-release procainamide. Serum procainamide concentration was determined using an immunochemistry assay. RESULTS: No adverse clinical effects were noted in any of the dogs studied. The average maximum serum concentration, average serum concentration, and average minimum serum concentration were 10.17, 7.13, and 3.07 µg/mL, respectively. The average time over a 12-h period during which procainamide concentration exceeded 12 µg/mL was 2.35 h, was between 4 and 12 µg/mL was 7.19 h, and was less than 4 µg/mL was 2.46 h. The average times at maximum concentration and minimum concentration were 18.67 and 12.25 h, respectively. CONCLUSIONS: Administration of sustained-release procainamide twice daily achieved targeted plasma concentrations in most dogs. Evaluation of serum trough concentrations should be considered owing to interanimal variability to confirm that serum concentrations are within the reported therapeutic range for an individual patient.

Preliminary investigation of orally administered benazepril in horses with left-sided valvular regurgitation.

BACKGROUND: Despite the paucity of data available, orally administered angiotensin-converting enzyme (ACE) inhibitors are empirically used in horses with valvular regurgitation. OBJECTIVE: Evaluate the echocardiographic and hormonal changes in response to oral benazepril in horses with left-sided valvular regurgitation. STUDY DESIGN: Prospective, randomised double-blind, placebo-controlled trial. METHODS: Horses with mitral valve (MR) and/or aortic valve regurgitation (AR) received oral benazepril (n = 6) at a dosage of 1 mg/kg q 12 h or a placebo (n = 5) for 28 days. Echocardiography was performed before drug administration and after 28 days of treatment. Plasma renin activity, serum ACE activity, angiotensin II concentration, aldosterone concentration and biochemical variables were measured before drug administration and after 7 and 28 days of treatment. RESULTS: Relative to baseline, horses treated with benazepril had statistically significant reduction in left ventricular internal diameter in systole (mean difference between groups = -0.97 cm; 95% CI = -1.5 to -0.43 cm), aortic sinus diameter (-0.31 cm; -0.54 to -0.07 cm), and percentage of the aortic annulus diameter occupied by the base of the AR jet (-17.05%; -31.17 to -2.93%) compared with horses receiving a placebo. In addition, horses treated with benazepril had a significantly greater increase in cardiac output (11.95 L/min; 1.17-22.73 L/min) and fractional shortening (7.59%; 3.3-11.88%) compared with horses receiving a placebo. Despite profound serum ACE inhibition, renin activity and concentrations of angiotensin II and aldosterone were not significantly different between treatment groups or among time points. MAIN LIMITATIONS: Very small sample size and short treatment period. CONCLUSIONS: Treatment with oral benazepril resulted in statistically significant echocardiographic changes that might indicate reduced cardiac afterload in horses with left-sided valvular regurgitation. Additional studies with a larger sample size will be necessary to determine if administration of benazepril is beneficial in horses with valvular regurgitation. The Summary is available in Spanish - see Supporting Information.

Attenuation of the blood pressure response to exogenous angiotensin I after oral administration of benazepril to healthy adult horses.

BACKGROUND: Benazepril has been shown to inhibit circulating angiotensin-converting enzyme (ACE) activity in horses but the optimal dosage is unknown. OBJECTIVES: To determine the lowest tested dose of benazepril that results in ≥75% attenuation in the response of arterial blood pressure (BP) to exogenous angiotensin I (ANG-I) administration. STUDY DESIGN: Prospective experimental study. METHODS: A total of 5 healthy horses were instrumented for the direct measurement of BP. Each horse received 4 intragastric doses of benazepril (0.5, 1, 2 and 4 mg/kg bwt) with a washout period of 7 days between doses. Prior to and 2, 12 and 24 h after benazepril administration, each horse received intravenous (i.v.) boluses of ANG-I at 20, 60 and 200 ng/kg. Attenuation of the systolic arterial pressure (SBP) response to ANG-I and serum ACE activity were quantified and expressed as percentage of inhibition. RESULTS: There was a significant effect of benazepril dose (P = 0.004) and time (P = 0.004) on the percentage of inhibition of the systolic pressor response to ANG-I. Regardless of benazepril dose, the percentage of inhibition was significantly greater 2 h after administration of benazepril compared with 12 and 24 h. At an ANG-I dose of 20 ng/kg, the percentage of inhibition after administration of benazepril at 1 mg/kg bwt (46.6 ± 18.9%) was significantly greater than that achieved after 0.5 mg/kg bwt (19 ± 14%) but not significantly different from that achieved at higher doses of benazepril. Benazepril doses ≥1 mg/kg bwt resulted in serum ACE inhibition of at least 90%. MAIN LIMITATIONS: Small sample size and resulting low statistical power. CONCLUSIONS: Attenuation of the rise in SBP in response to ANG-I after administration of benazepril is modest in horses despite adequate serum ACE inhibition. A dose of 1 mg/kg bwt would be recommended for future investigations of benazepril for the management of cardiovascular diseases in horses.

Congestive heart failure caused by transvenous pacemaker lead prolapse and associated right ventricular outflow tract obstruction in a dog.

A 16-year-old dog was presented for cough as well as increased respiratory rate and effort three years after implantation of a single-lead transvenous artificial pacemaker system. Thoracic radiographs and echocardiography disclosed prolapse of the pacemaker lead into the main pulmonary artery, causing severe pulmonary insufficiency and right-sided volume overload. Repositioning of the pacemaker lead led to improvement of pulmonary insufficiency and resolution of the dog's clinical signs and cavitary effusions. This case describes a late complication of pacemaker implantation that may be avoided by appropriate use of the manufacturer-provided anchoring sleeve and avoidance of excessive lead redundancy.

Cardiovascular effects of pimobendan in healthy mature horses.

REASONS FOR PERFORMING STUDY: Pimobendan is an inodilator used in dogs for the management of heart failure due to myxomatous valve disease or dilated cardiomyopathy. The lack of data regarding the effects of pimobendan in horses prevents the rational use of this drug. OBJECTIVE: To determine the cardiovascular effects of pimobendan in healthy mature horses. STUDY DESIGN: Randomised experimental study. METHODS: Five horses were fasted overnight prior to receiving i.v. pimobendan (0.25 mg/kg bwt), intragastric (i.g.) pimobendan (0.25 mg/kg bwt) or i.g. placebo with a washout period of one week between each administration. Horses were instrumented for the measurement of right ventricular (RV) minimum pressure, RV maximum pressure, RV end diastolic pressure, and maximum rate of increase and decrease in RV pressure before and 0.5, 1, 2, 4, and 8 h after drug administration. Arterial blood pressure, central venous pressure, cardiac output and heart rate were measured at the same time points. Data were expressed as a maximum percentage of change over baseline values. RESULTS: There were no adverse effects associated with administration of pimobendan. The percentage increase in heart rate was significantly greater for horses given pimobendan i.g. (33 ± 4%) and i.v. (36 ± 14%) than for those given a placebo (-2 ± 7%). The percentage increase in maximum rate of increase in RV pressure (35 ± 36%) and the percentage decrease in minimum pressure (47 ± 24%) and end diastolic pressure (34 ± 13%) were significantly greater in horses given pimobendan i.v. than in those given placebo. Other variables measured were not significantly different between treatment groups. CONCLUSION: Pimobendan administered i.v. has positive chronotropic and inotropic effects in healthy mature horses and warrants further investigation for the treatment of heart failure in horses.

The influence of enalapril and spironolactone on electrolyte concentrations in Doberman pinschers with dilated cardiomyopathy.

The combination of an angiotensin-converting enzyme inhibitor (ACEI) with an aldosterone receptor antagonist can increase serum potassium and magnesium and lower serum sodium concentrations. The objective of this study was to retrospectively determine whether an ACEI and spironolactone can be co-administered to Doberman pinschers with occult dilated cardiomyopathy without serious adverse influences on serum electrolyte concentrations. Between 2001 and 2007, 26 client-owned Doberman pinschers were given enalapril, spironolactone, and carvedilol and followed for at least 6 months. Most dogs had been prescribed mexiletine for ventricular tachyarrhythmia suppression. Dogs were treated with pimobendan when congestive heart failure was imminent. Baseline and follow-up (3-10 visits) color-flow Doppler echocardiograms, serum urea nitrogen (SUN), creatinine, sodium, potassium, and magnesium concentration data were tabulated. Compared to baseline data, there were no significant changes in serum sodium or serum creatinine concentrations. Serum magnesium (P = 0.003), serum potassium (P = 0.0001), and SUN (P = 0.0001) concentrations increased significantly with time. Although the combination of ACEI and spironolactone was associated with significant increases in magnesium, potassium, and SUN concentrations, these changes were of no apparent clinical relevance. At the dosages used in this study, this combination of drugs appears safe.

Pharmacodynamic evaluation of 4 angiotensin-converting enzyme inhibitors in healthy adult horses.

BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors are used in horses with cardiovascular disorders despite the paucity of available data regarding their efficacy. HYPOTHESIS: The degree of serum ACE inhibition varies considerably between drugs. ANIMALS: Eight healthy adult horses. METHODS: Randomized prospective study. Horses were fasted overnight prior to receiving one of 4 ACE inhibitors intragastrically, administered at one of 2 dosages, using a randomized Latin square design (benazepril: 0.5 and 0.25 mg/kg; ramipril: 0.3 and 0.1 mg/kg; quinapril: 0.25 and 0.125 mg/kg; perindopril: 0.1 and 0.05 mg/kg). Serum ACE activity was measured using a kinetic spectrophotometric method. RESULTS: There was a significant effect of drug and dosage on maximum ACE inhibition (I(max)), ACE inhibition 24 hours after administration (I(24h)), and area under the curve (AUC(0-48h)). Benazepril at 0.5 mg/kg resulted in significantly higher I(max) (86.9 ± 7.0%) and I(24h) (60.3 ± 7.9%) compared to the other drugs. There was a significant decrease in indirect blood pressure (BP) over time after administration of each drug, but differences in BP were not significantly different between drugs. Pharmacodynamic variables measured after administration of benazepril to horses with free access to hay were not significantly different from those obtained after fasting. Administration of benazepril orally once daily for 7 days did not result in a cumulative effect on ACE inhibition. CONCLUSIONS AND CLINICAL IMPORTANCE: Of the ACE inhibitors tested, oral benazepril (0.5 mg/kg) is the most effective at inhibiting serum ACE activity in healthy horses.

Doppler and volumetric echocardiographic methods for cardiac output measurement in standing adult horses.

BACKGROUND: Cardiac output (CO) is not routinely measured in critically ill adult horses because of invasiveness of currently validated methods. Noninvasive CO monitoring would complement clinical assessment of hemodynamic status in adult horses. HYPOTHESIS: Volumetric methods for measuring CO will have better agreement with lithium dilution than Doppler-based methods. ANIMALS: Eight healthy adult horses. METHODS: Prospective study. CO was manipulated with continuous rate infusions of dobutamine and romifidine to achieve high and low CO states, respectively. At each level, CO was measured by lithium dilution and various echocardiographic methods. Images stored as video loops were reviewed by an individual blinded to the lithium dilution results. RESULTS: Lithium dilution determinations of CO ranged between 16.6 and 63.0 L/min. There was a significant effect of method of CO measurement (P < .001), but no significant effect of CO level (P = .089) or interaction between level and method (P = .607) on the absolute value of the bias. The absolute values of the bias of the right ventricular outflow tract (RVOT) Doppler, Simpson, 4-chamber area-length, and bullet methods [5.5, 6.1, 6.5, 8.8 L/min, respectively] were significantly lower than that of the left ventricular outflow tract (LVOT) Doppler or cubic methods [14.8, 24.3 L/min, respectively]. CONCLUSIONS AND CLINICAL IMPORTANCE: The 4-chamber area-length, Simpson, bullet, and RVOT Doppler provided better agreement with lithium dilution than the other methods evaluated. These methods warrant further investigation for use in critically ill adult horses.

Prevalence of trypanosome infections in dogs from Chagas disease endemic regions in Panama, Central America.

The prevalence of canine trypanosomosis was investigated in two Chagas disease endemic rural communities located in the central region of Panama. Serologic tests for Trypanosoma cruzi infection revealed a prevalence of 11.1%. Hemocultures coupled with PCR analysis demonstrated a Trypanosoma rangeli infection rate of 5.1%. An overall trypanosome infection index of 16.2% (16/99) was detected in this canine population. One dog had a mixed infection of T. cruzi and T. rangeli. Six of the trypanosome-infected dogs belong to people who were diagnosed of Chagas disease. We conclude that dogs from this rural area of Panama are frequently infected with trypanosomes transmitted by the sylvatic vector, Rhodnius pallescens, and suggest that dogs are important in the peridomestic transmission cycle of trypanosomes as reservoirs and hosts. The epidemiological implications of these findings are discussed.

Characterization of glucose-repression-resistant mutants of Bacillus subtilis: identification of the glcR gene.

In Bacillus subtilis, carbon catabolite repression (CCR) is mediated by the pleiotropic repressor CcpA and by ATP-dependent phosphorylation of the HPr protein of the phosphotransferase system (PTS). In this study, we attempted to identify novel genes that are involved in the signal transduction pathway that ultimately results in CCR in the presence of repressing carbon sources such as glucose. Seven mutants resistant to glucose repression of the levanase operon were isolated and characterized. All mutations were trans-acting and pleiotropic as determined by analyzing CCR of beta-xylosidase and of the sacPA and bglPH operon. Moreover, all mutations specifically affected repression exerted by glucose but not by other sugars. The mutations were mapped to three different loci on the genetic map, ptsG, glcR, and pgi. These three genes encode proteins involved in glucose metabolism. A novel repressor gene, glcR (ywpI), defined by two mutations, was studied in more detail. The glcR mutants exhibit loss of glucose repression of catabolic operons, a deficiency in glucose transport, and absence of expression of the ptsG gene. The mutant GlcR proteins act as super-repressors of ptsG expression.

The two-component system ArlS-ArlR is a regulator of virulence gene expression in Staphylococcus aureus.

Staphylococcus aureus is a major human pathogen that produces many virulence factors in a temporally regulated manner controlled by at least two global virulence regulatory loci (agr and sarA). We identified previously a two-component system, ArlS-ArlR, that modifies the activity of extracellular serine protease and may be involved in virulence regulation. Here, we show that mutations in either arlR or arlS increase the production of secreted proteins [alpha-toxin (Hla), beta-haemolysin, lipase, coagulase, serine protease (Ssp)] and especially protein A (Spa). Furthermore, the pattern of proteins secreted by both mutants was strikingly different from that of the wild-type strain. Transcriptional fusions showed that expression of hla, ssp and spa was higher in both mutants than in the wild-type strain, indicating that the arl operon decreases the production of virulence factors by downregulating the transcription of their genes. The arl mutation did not change spa expression in an agrA mutant or in a sarA mutant, suggesting that both the sarA and the agr loci are required for the action of arl on spa. Northern blot analyses indicated that the arl mutation increased the synthesis of both RNA II and RNA III, but decreased sarA transcription. Finally, arl was not autoregulated, but its expression was stimulated by agr and sarA. These results suggest that the Arl system interacts with both agr and sarA regulatory loci to modulate the virulence regulation network.

Regulation of the acetoin catabolic pathway is controlled by sigma L in Bacillus subtilis.

Bacillus subtilis grown in media containing amino acids or glucose secretes acetate, pyruvate, and large quantities of acetoin into the growth medium. Acetoin can be reused by the bacteria during stationary phase when other carbon sources have been depleted. The acoABCL operon encodes the E1alpha, E1beta, E2, and E3 subunits of the acetoin dehydrogenase complex in B. subtilis. Expression of this operon is induced by acetoin and repressed by glucose in the growth medium. The acoR gene is located downstream from the acoABCL operon and encodes a positive regulator which stimulates the transcription of the operon. The product of acoR has similarities to transcriptional activators of sigma 54-dependent promoters. The four genes of the operon are transcribed from a -12, -24 promoter, and transcription is abolished in acoR and sigL mutants. Deletion analysis showed that DNA sequences more than 85 bp upstream from the transcriptional start site are necessary for full induction of the operon. These upstream activating sequences are probably the targets of AcoR. Analysis of an acoR'-'lacZ strain of B. subtilis showed that the expression of acoR is not induced by acetoin and is repressed by the presence of glucose in the growth medium. Transcription of acoR is also negatively controlled by CcpA, a global regulator of carbon catabolite repression. A specific interaction of CcpA in the upstream region of acoR was demonstrated by DNase I footprinting experiments, suggesting that repression of transcription of acoR is mediated by the binding of CcpA to the promoter region of acoR.

The CtsR regulator of stress response is active as a dimer and specifically degraded in vivo at 37 degrees C.

CtsR (class three stress gene repressor) negatively regulates the expression of class III heat shock genes (clpP, clpE and the clpC operon) by binding to a directly repeated heptanucleotide operator sequence (A/GGTCAAA NAN A/GGTCAAA). CtsR-dependent genes are expressed at a low level at 37 degrees C and are strongly induced under heat shock conditions. We performed a structure/function analysis of the CtsR protein, which is highly conserved among low G+C Gram-positive bacteria. Random chemical mutagenesis, in vitro cross-linking, in vivo co-expression of wild-type and mutant forms of CtsR and the construction of chimeric proteins with the DNA-binding domain of the lambda CI repressor allowed us to identify three different functional domains within CtsR: a helix-turn-helix DNA-binding domain, a dimerization domain and a putative heat-sensing domain. We provide evidence suggesting that CtsR is active as a dimer. Transcriptional analysis of a clpP'-bgaB fusion and/or Western blotting experiments using antibodies directed against the CtsR protein indicate that ClpP and ClpX are involved in CtsR degradation at 37 degrees C. This in turn leads to a low steady-state level of CtsR within the cell, as CtsR negatively autoregulates its own synthesis. This is the first example of degradation of a repressor of stress response genes by the Clp ATP-dependent protease.

The clpP multigenic family in Streptomyces lividans: conditional expression of the clpP3 clpP4 operon is controlled by PopR, a novel transcriptional activator.

The clpP genes are widespread among living organisms and encode the proteolytic subunit of the Clp ATP-dependent protease. These genes are present in a single copy in most eubacteria. However, five clpP genes were identified in Streptomyces coelicolor. The clpP1 clpP2 operon was studied: mutations affected the growth cycle in various Streptomyces. Here, we report studies of the expression of the clpP3 clpP4 operon in Streptomyces lividans. The clpP3 operon was induced in a clpP1 mutant strain, and the regulation of expression was investigated in detail. The product of the putative regulator gene, downstream from clpP4, was purified. Gel migration shift assays and DNase I footprinting showed that this protein binds to the clpP3 promoter and recognizes a tandem 6 bp palindromic repeat (TCTGCC-3N-GGCAGA). In vivo, this DNA-binding protein, named PopR, acts as an activator of the clpP3 operon. Studies of popR expression indicate that the regulator is probably controlled at the post-transcriptional level.

Expression of a new operon from Bacillus subtilis, ykzB-ykoL, under the control of the TnrA and PhoP-phoR global regulators.

The ykzB and ykoL genes encode two peptides, of 51 and 60 amino acids, the functions of which are unknown. The ykzB and tnrA genes are contiguous and transcribed divergently. Expression of ykzB and ykoL is induced by glutamate and is under the control of the TnrA global regulator of nitrogen utilization. TnrA regulated its own synthesis in glutamate minimal medium. Two DNA sequences (TnrAB1 and TnrAB2) homologous to the TnrA binding site are present in the region between tnrA and ykzB. Deletion mapping indicated that the TnrAB2 binding site was involved in activation of the ykzB promoter. In addition, transcription of tnrA depends on the presence of the TnrAB1 binding site. The ykzB and ykoL genes are probably in the same transcriptional unit. A single promoter involved in transcription in the presence of glutamate was mapped by primer extension. ykoL expression was induced by phosphate limitation and depended on the PhoP-PhoR two-component regulatory system. Its promoter was mapped to the region between ykoL and ykzB. Four boxes similar to the PhoP binding site are present upstream from the ykoL promoter. These boxes are probably recognized by PhoP approximately P during the activation of transcription in phosphate limitation conditions.

Production of Cry11A and Cry11Ba toxins in Bacillus sphaericus confers toxicity towards Aedes aegypti and resistant Culex populations.

Cry11A from Bacillus thuringiensis subsp. israelensis and Cry11Ba from Bacillus thuringiensis subsp. jegathesan were introduced, separately and in combination, into the chromosome of Bacillus sphaericus 2297 by in vivo recombination. Two loci on the B. sphaericus chromosome were chosen as target sites for recombination: the binary toxin locus and the gene encoding the 36-kDa protease that may be responsible for the cleavage of the Mtx protein. Disruption of the protease gene did not increase the larvicidal activity of the recombinant strain against Aedes aegypti and Culex pipiens. Synthesis of the Cry11A and Cry11Ba toxins made the recombinant strains toxic to A. aegypti larvae to which the parental strain was not toxic. The strain containing Cry11Ba was more toxic than strains containing the added Cry11A or both Cry11A and Cry11Ba. The production of the two toxins together with the binary toxin did not significantly increase the toxicity of the recombinant strain to susceptible C. pipiens larvae. However, the production of Cry11A and/or Cry11Ba partially overcame the resistance of C. pipiens SPHAE and Culex quinquefasciatus GeoR to B. sphaericus strain 2297.

ClpE, a novel type of HSP100 ATPase, is part of the CtsR heat shock regulon of Bacillus subtilis.

Clp ATPases, which include the ubiquitous HSP100 family, are classified according to their structural features and sequence similarities. During the course of the Bacillus subtilis genome sequencing project, we identified a gene encoding a new member of the HSP100 family. We designated this protein ClpE, as it is the prototype of a novel subfamily among the Clp ATPases, and have identified homologues in several bacteria, including Listeria monocytogenes, Enterococcus faecalis, Streptococcus pyogenes, Streptococcus pneumoniae, Lactobacillus sakei and Clostridium acetobutylicum. A unique feature of these Hsp100-type Clp ATPases is their amino-terminal zinc finger motif. Unlike the other class III genes of B. subtilis (clpC and clpP ), clpE does not appear to be required for stress tolerance. Transcriptional analysis revealed two sigmaA-type promoters, expression from which was shown to be inducible by heat shock and puromycin treatment. Investigation of the regulatory mechanism controlling clpE expression indicates that this gene is controlled by CtsR and is thus a member of the class III heat shock genes of B. subtilis. CtsR negatively regulates clpE expression by binding to the promoter region, in which five CtsR binding sites were identified through DNase I footprinting and sequence analysis.

Role of bkdR, a transcriptional activator of the sigL-dependent isoleucine and valine degradation pathway in Bacillus subtilis.

A new gene, bkdR (formerly called yqiR), encoding a regulator with a central (catalytic) domain was found in Bacillus subtilis. This gene controls the utilization of isoleucine and valine as sole nitrogen sources. Seven genes, previously called yqiS, yqiT, yqiU, yqiV, bfmBAA, bfmBAB, and bfmBB and now referred to as ptb, bcd, buk, lpd, bkdA1, bkdA2, and bkdB, are located downstream from the bkdR gene in B. subtilis. The products of these genes are similar to phosphate butyryl coenzyme A transferase, leucine dehydrogenase, butyrate kinase, and four components of the branched-chain keto acid dehydrogenase complex: E3 (dihydrolipoamide dehydrogenase), E1alpha (dehydrogenase), E1beta (decarboxylase), and E2 (dihydrolipoamide acyltransferase). Isoleucine and valine utilization was abolished in bcd and bkdR null mutants of B. subtilis. The seven genes appear to be organized as an operon, bkd, transcribed from a -12, -24 promoter. The expression of the bkd operon was induced by the presence of isoleucine or valine in the growth medium and depended upon the presence of the sigma factor SigL, a member of the sigma 54 family. Transcription of this operon was abolished in strains containing a null mutation in the regulatory gene bkdR. Deletion analysis showed that upstream activating sequences are involved in the expression of the bkd operon and are probably the target of bkdR. Transcription of the bkd operon is also negatively controlled by CodY, a global regulator of gene expression in response to nutritional conditions.

CtsR, a novel regulator of stress and heat shock response, controls clp and molecular chaperone gene expression in gram-positive bacteria.

clpP and clpC of Bacillus subtillis encode subunits of the Clp ATP-dependent protease and are required for stress survival, including growth at high temperature. They play essential roles in stationary phase adaptive responses such as the competence and sporulation developmental pathways, and belong to the so-called class III group of heat shock genes, whose mode of regulation is unknown and whose expression is induced by heat shock or general stress conditions. The product of ctsR, the first gene of the clpC operon, has now been shown to act as a repressor of both clpP and clpC, as well as clpE, which encodes a novel member of the Hsp100 Clp ATPase family. The CtsR protein was purified and shown to bind specifically to the promoter regions of all three clp genes. Random mutagenesis, DNasel footprinting and DNA sequence deletions and comparisons were used to define a consensus CtsR recognition sequence as a directly repeated heptad upstream from the three clp genes. This target sequence was also found upstream from clp and other heat shock genes of several Gram-positive bacteria, including Listeria monocytogenes, Streptococcus salivarius, S. pneumoniae, S. pyogenes, S. thermophilus, Enterococcus faecalis, Staphylococcus aureus, Leuconostoc oenos, Lactobacillus sake, Lactococcus lactis and Clostridium acetobutylicum. CtsR homologues were also identified in several of these bacteria, indicating that heat shock regulation by CtsR is highly conserved in Gram-positive bacteria.

Clinical comparison of three methods to measure blood pressure in nonsedated dogs.

OBJECTIVE: To determine arterial blood pressure in client-owned dogs, using direct arterial puncture, oscillometry, and Doppler ultrasonography in a clinical setting. DESIGN: Prospective study. ANIMALS: 8 clinically normal client-owned dogs. PROCEDURE: Blood pressures of nonsedated dogs were measured simultaneously, using each of the 3 methods. Mean values obtained were compared with published mean values. Ability of noninvasive methods (Doppler ultrasonography and oscillometry) to accurately predict results of the invasive method, and relationships between blood pressure and age, body weight, and degree of patient anxiety were determined. RESULTS: Calculated ranges of values (mean +/- 2 SD) determined by direct arterial puncture were: systolic pressure, 114 to 194 mm Hg; diastolic pressure, 66 to 102 mm Hg; and mean pressure, 85 to 129 mm Hg. Ranges determined by use of oscillometry were: systolic, 110 to 190 mm Hg; diastolic, 35 to 107 mm Hg; and mean, 78 to 138 mm Hg. Ultrasonographic and oscillometric values did not accurately predict direct values, but mean values of systolic and mean pressures were similar among methods. Relationships were not detected between age or body weight and blood pressure. Significant differences in blood pressure were not detected between anxious and nonanxious dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Mean values of systolic, diastolic, and mean arterial blood pressure measured in nonsedated client-owned dogs, using invasive and noninvasive methods in a clinical setting, are comparable with those determined for acclimatized, trained, or sedated dogs. However, results of noninvasive methods may not accurately reflect direct values.