Comparison of iterated single-step and Bayesian regressions on genomic evaluations for age at 100 kg in swine.

The effects of modified single-step genomic best linear unbiased prediction (ssGBLUP) iterations on GEBV and SNP were investigated using 85,388 age at 100 kg phenotypes from the BRF SA breeding program Landrace pure line animals, off-tested between 2002 and 2013. Pedigree data comprised animals born between 1999 and 2013. A total of 1,068 animals were assigned to the training population, in which all of them had genotypes, original and corrected age at 100 kg phenotypes, and weighted deregressed proof records. A total of 100 genotyped animals, with high accuracy age at 100 kg estimated breeding values, were assigned to the validation population. After applying the quality control workflow, a set of 41,042 SNP was used for the analysis. Standard and modified ssGBLUP, BayesCπ, and Bayesian Lasso were compared, and their predictive abilities were accessed by approximate true and GEBV correlations. Modified ssGBLUP iteration effects on SNP estimates and GEBV were relevant, in which assigned differential weights and shrinkage caused important losses on ssGBLUP predictive ability for age at 100 kg GEBV. Even though ssGBLUP accuracy can be equal or better than the compared Bayesian methods, additional gains can be obtained by correctly identifying the number of iterations required for best ssGBLUP performance.

Avaliação de características de desempenho e de carcaça de codornas de corte por meio da análise de componentes principais / Evaluation of production and carcass traits of meat - type quails by principal components analysis

Foram utilizados dados de 288 codornas de corte (Coturnix coturnix coturnix) para avaliar a possibilidade de resumir a informação contida no complexo de variáveis originais, eliminando-se variáveis inexpressivas por meio da técnica de componentes principais. Foram registrados o peso vivo (PVIVO) e pesos do peito (PPEITO), das coxas (PCOXA), da gordura abdominal (GA), das vísceras comestíveis (fígado, moela e coração) (FIG, MOELA e CORA) e da carcaça eviscerada (PCEVIS). As carcaças foram secas e trituradas para a avaliação do teor matéria seca (MS), gordura (GORD) e proteína bruta (PB). Dos 11 componentes principais, sete (63,6 por cento) apresentaram variância menor que 0,7 (autovalor inferior a 0,7), sendo sugeridas para descarte, respectivamente, em ordem de menor importância, para explicar a variação total das seguintes variáveis: PCEVIS, PPEITO, PCOXA, CORA, FIG MOELA e GORD. Com base nos resultados, recomenda-se manter as seguintes variáveis em experimentos futuros: PVIVO, MS, PB e GA.

Records on 288 meat type quails (Coturnix coturnix coturnix) were used to identify independent and informative variables by eliminating inexpressive variables by means of principal component analysis. The following performance traits were recorded: live body weight (LBW), eviscerated carcass weight (CW), whole leg weight (WLW), breast weight (BW), abdominal fat pad weight (FW), and giblets weight (liver, gizzard, and heart) (LIW, GW, and HW). The carcasses were also dried and grounded to evaluate dry matter (DM), fat (FA,T) and crude protein (CP) contents. Out of 11 principal components, seven (63.6 percent) showed variance lower than 0.7 (eigenvalue lower than 0.7). The following traits were discarded because they showed inexpressive contribuitions for the total variation: CW, BW, WLW, HW, LIW, GW, and FAT. Based on the results, it is recommended to record the following variables in future experiments: LBW, DM, CP, and FW.

Estudo de características de produção de matrizes de corte por meio da análise de componentes principais / Study of meat-type chickens production traits by principal components analysis

Avaliou-se o descarte de variáveis de produção, em análises de componentes principais, de três linhagens de matrizes de corte do Programa de Melhoramento Genético da Universidade Federal de Viçosa, utilizando informações de 270 aves, sendo 90 de cada linhagem. As características analisadas foram dias para postura do primeiro ovo (DPPO), taxa de postura da 22ª a 56ª semana (TP), peso médio individual na 32ª (PMI1), na 40ª (PMI2), na 48ª (PMI3), na 56ª (PMI4) e na 64ª semana (PMI5) e peso médio do ovo, obtido pela média da pesagem de três ovos na 32ª (PMO1), na 40ª (PMO2), na 48ª (PMO3), na 56ª (PMO4) e na 64ª semana (PMO5). Dos 12 componentes principais, sete apresentaram variância menor do que 0,7 (autovalor menor do que 0,7), sugerindo-se sete variáveis para descarte. As variáveis descartadas foram aquelas que apresentaram maiores coeficientes, em valor absoluto, a partir do último componente principal. Observou-se correlação linear simples e significativa entre as variáveis descartadas e as não descartadas, que indica redundância de variáveis, razão do descarte. Recomendam-se as variáveis: DPPO, TP, PM14, PMO1 e PMO4 para o estudo de características da produção de matrizes de frango de corte por meio da análise de componentes principais.

Records of 270 meat-type chickens from three lines, 90 of each one, were used to discard variables in a principal component analysis. Data were obtained from meat-type chicken lines of the genetic breeding program of the Universidade Federal de Viçosa. The following traits were evaluated: days at first egg (DFE), egg production rate (EPR) from 22nd to 56th week, body weights at 32nd (BW1), 40th (BW2), 48th (BW3), 56th (BW4), and 64th weeks of age (BW5), and average of three egg weights, at 32nd (EW1), 40th (EW2), 48th (EW3), 56th (EW4) and at 64th weeks (EW5). From the 12 principal components, seven showed variance lower than 0,7 (eigenvalue lower than 0,7), suggesting seven variables to be discarded. Variables which showed the highest coefficients, in absolute value, in the last principal component were discarded. Highly correlated variables with the smaller principal components variance explain a small part of the whole variation. In addition, discarded variables in function of the significant simple linear correlation with the nondiscorded variable, were considered redundants. The variables DFE, EPR, BW4, EW1, and EW4 are recommended for principal component analysis of broiler matrix.

Coordination of microtubules and the actin cytoskeleton is important in osteoclast function, but calcitonin disrupts sealing zones without affecting microtubule networks.

Bone-resorbing osteoclasts form sealing zones and ruffled borders toward the bone surface. The sealing zone consists of a ring-like alignment of F-actin dots and surrounds the ruffled border, from which protons are secreted into the bone surface. Vacuolar-type proton ATPase (V-ATPase) in osteoclasts is a ruffled border-associated enzyme responsible for the proton secretion. We studied the interaction between microtubules and the actin cytoskeleton in osteoclasts. Confocal microscopic observation revealed that osteoclasts on glass coverslips, dentine slices and Osteologictrade mark discs formed the ring-like structure of F-actin dots, and microtubules overlapped the top of the F-actin dots. Osteoclasts cultured on dentine formed resorption pits within 48 h. The treatment of osteoclasts with cytochalasin D, an F-actin-depolymerizing reagent, induced perturbation of the microtubules in osteoclasts on glass and inhibited their pit-forming activity on dentine in a dose-dependent and reversible manner. Conversely, nocodazole, a microtubule-depolymerizing reagent, disrupted sealing zones and inhibited pit-forming activity of osteoclasts in a dose-dependent and reversible manner. V-ATPase showed a tendency to be localized inside sealing zones in osteoclasts. Treatment of osteoclasts with calcitonin induced both disruption of sealing zones and dispersion of V-ATPase to the whole area of the cytoplasm within 60 min. The microtubule networks in osteoclasts remained unchanged for 60 min even in the presence of calcitonin. These results suggest that coordination of the actin cytoskeleton and microtubules is important in the function of osteoclasts, but calcitonin selectively affects the actin cytoskeleton and induces the dispersion of V-ATPase without causing significant changes in the microtubules.

Screening of antibiotic residues in ewes' milk destined to cheese by a commercial microbiological inhibition assay.

Bulk ewes' milk from Spanish dairy farms in the Castilla-La Mancha region and destined for production of protected denomination of origin (PDO) Manchego cheese were analysed each month for antimicrobial residues during the course of 1 year. A microbiological assay specific for ewes' milk (Eclipse '100ov') was used. The number of positive samples by the Eclipse '100ov' test was 2.6%. A second examination of positives following heat treatment at 82 degrees C for 10 min showed a reduction of up to 0.9% (i.e. 63% of the samples detected corresponded to 'false-positives'). Of the confirmed positives, 25% were identified as beta-lactams by a penicillinase solution; the remainder corresponded to antimicrobial compounds that could not be identified. The month of collection was related to the probability of positive results, but to no other factors such as somatic cell counts, bacteriology or composition (fat and protein). The highest rates of positives were observed in September and October. Finally, the results were compared with those obtained by the Delvotest SP method, which showed the detection of a higher number of positive samples compared with the Eclipse '100ov' method.

Quantum control of unidirectional rotations of a chiral molecular motor.

A quantum control method is presented for designing electric fields of laser pulses to drive a chiral molecular motor in desired, rotational directions. Intuitive or counter-intuitive rotational motion of a chiral motor, 2-chloro-5-methyl-cyclopenta-2,4-dienecarbaldehyde, was controlled by electric fields of ps-laser pulses with mid-infrared central frequencies. The control mechanism is discussed by analyzing the time- and frequency-resolved spectrum of the electric fields of the laser pulses. Timing of laser pulses is the essential factor for controlling unidirectional motions.

Occurrence of antibiotic residues in milk from Manchega ewe dairy farms.

Ewe milk samples from different ovine dairy farms from the Castilla-La Mancha region of Spain were collected from bulk tanks to estimate the occurrence of antibiotic residues in raw and heated (82 degrees C, 10 min) milk by the Delvotest SP test. The month of collection, somatic cell counts, and bacteriology were analyzed and examined by means of a logistic regression model. The screening of a total of 2686 raw milk samples showed 1.7% "positive" and 2.1% "doubtful" results, which decreased after heating treatment to 1.3% and 0.4%, respectively. "Positive" and "doubtful" samples were identified by penicillinase and p-aminobenzoic acid solutions, and the majority of them corresponded to antimicrobials different than beta-lactams or sulfonamides. By applying a logistic regression model, a significant effect of month of collection and bacteriology was observed in the initial screening and after the heat treatment. The highest percentages of "positive plus doubtful" results were observed in late summer-early autumn. A slight peak was also observed in spring in raw milk samples. Bacteriology was positively correlated with "positive plus doubtful" results.

Performances of antibiotic screening tests in determining the persistence of penicillin residues in ewe's milk.

Milk collected at 12-h intervals throughout 6 days from three groups of Manchega ewes (n = 12 per group), treated intramuscularly with beta-lactams (benzyl penicillin procaine, ampicillin, and amoxicillin, respectively), was evaluated for antibiotic residue persistence with four microbial inhibitor tests (BRT MRL, CH ATK P&S, Delvotest SP, and Eclipse 100ov) and one enzymatic test (Penzym 100). Antibiotic depletion time was established using a logistic regression model. A clear effect (P < 0.0001) of milking order on the response of all tests was observed with the three antibiotics, but no significant effects were found for milk yield. Except with Eclipse 100ov, positive tests were observed after the recommended withdrawal period of benzyl penicillin procaine (five milkings) from 2% (Delvotest SP) to 11% (CH ATK P&S). There were almost no positive responses beyond the withdrawal period (six milkings) of ampicillin, except for the Penzym 100 test (7%). Residues of amoxicillin were found to persist beyond the six milkings established as the withdrawal period, from 2.8% (Eclipse 100ov) to 72.4% (CH ATK P&S) of positive cases. Higher frequencies of doubtful cases were found with BRT MRL and Delvotest SP assays with the three beta-lactams. Positive and doubtful results could be obtained when milk samples from individual ewes were analyzed using BRT MRL, CH ATK P&S, Delvotest SP, and Penzym 100 tests, even if farmers follow the antibiotic withdrawal periods.

Blockade of superoxide generation prevents high-affinity immunoglobulin E receptor-mediated release of allergic mediators by rat mast cell line and human basophils.

BACKGROUND: Previous studies have shown that rat peritoneal mast cells and mast cell model rat basophilic leukaemia (RBL-2H3) cells generate intracellular reactive oxygen species (ROS) in response to antigen challenge. However, the physiological significance of the burst of ROS is poorly understood. OBJECTIVE: The present study was undertaken to investigate the role of superoxide anion in mediator release in rat and human cell systems. METHODS: RBL-2H3 cells were directly stimulated with anti-rat FcepsilonRI alpha-subunit monoclonal antibody (mAb). For the analysis of human cell system, leucocytes were isolated by dextran sedimentation from healthy volunteers or from patients, and challenged either with anti-human FcepsilonRI mAb or with the relevant antigens. Superoxide generation was determined by chemiluminescence-based methods. The releases of histamine and leukotrienes (LT)s were determined by enzyme-linked immunosorben assay (ELISA). RESULTS: Cross-linking of FcepsilonRI on RBL-2H3 cells or on human leucocytes from healthy donors by the anti-FcepsilonRI mAb resulted in a rapid generation of superoxide anion, as determined by chemiluminescence using superoxide-specific probes. Similarly, leucocytes from patients generated superoxide anion in response to the challenge with the relevant allergen but not with the irrelevant allergen. Furthermore, diphenyleneiodonium (DPI), a well-known inhibitor of flavoenzymes suppressed the superoxide generation and the release of histamine and LTC4 induced by the anti-FcepsilonRI mAb or by allergen in parallel. CONCLUSION: These results indicate that both RBL-2H3 cells and human basophils generate superoxide anion upon FcepsilonRI cross-linking either by antibody or by allergen challenge and that blockade of the generation prevents the release of allergic mediators. The findings strongly support the role of superoxide generation in the activation of mast cells and basophils under both physiological and pathological conditions. The findings suggest that drugs regulating the superoxide generation have potential therapeutic use for allergic disorders.

Cell death with predominant apoptotic features in Saccharomyces cerevisiae mediated by deletion of the histone chaperone ASF1/CIA1.

BACKGROUND: Although no potential homologues of multicellular apoptotic genes (e.g. Bax, Bak, Bcl-2, caspases and p53) have been identified in a unicellular eukaryote, previous reports contain several implications of the apoptotic behaviour of yeasts (i.e. Saccharomyces cerevisiae and Schizosaccharomyces pombe). Therefore, whether or not yeast undergoes apoptosis has been a topic of some debate. hCCG1, which is the largest subunit of TFIID and a histone acetyltransferase, appears to be involved in the regulation of apoptosis. The factor hCIA interacts with hCCG1 and functions as a histone chaperone in mammalian cells; its homologue in yeast is Asf1p/Cia1p. Therefore, we anticipated that a yeast mutant in Asf1p/Cia1p would be a valuable tool for studying apoptosis in yeast. RESULTS: We established a strain of S. cerevisiae lacking the histone chaperone ASF1/CIA1. This disruptant, asf1/cia1, arrested preferentially at the G2/M-phase and died. We systematically analysed the phenotype associated with the death of this mutant yeast and identified many changes, such as fragmentation of the nuclei, condensation and fragmentation of chromatin, reduction of the mitochondrial membrane-potential, dysfunction of the mitochondrial proton pump, and a discernible release of cytochrome c to cytoplasm that resembles those in apoptotic multicellular organisms. Other changes potentially associated with the death in our mutant included a reduction in the vacuolar membrane potential, dysfunction of the vacuolar proton pump, reduction of endocytosis, and the presence of many autophagic bodies. However, these mutant yeast cells also showed cellular enlargement, which is characteristic of necrosis. CONCLUSIONS: Cell death in S. cerevisiae occurs with a phenotype that largely resembles apoptosis in multicellular organisms, but that has some features of necrosis. Therefore, we indicate that yeast undergoes a 'prototypal active cell death' that retains some characteristics of passive cell death (necrosis). In addition, we think that active cell death is ubiquitously the essential attribute of life. Although such an active cell death system in yeast remains open to confirmation, we speculate that deletion of the histone chaperone Asf1p/Cia1p inhibits the normal assembly/disassembly of nucleosomes in yeast and thereby initiates the active cell death system.

[A case of acute renal failure and liver dysfunction induced by carbamazepine(CBZ)].

A 56-year-old female with symptomatic epilepsy was admitted to our hospital because of acute renal failure(ARF) and liver dysfunction(LD) after receiving CBZ for two months. She had suffered a drug eruption caused by phenobarbital and valproate six months previously. Renal and liver biopsies presented acute interstitial nephritis and active chronic hepatitis, respectively. Drug-induced lymphocyte stimulating test showed CBZ positivity. Steroid therapy resulted in recovery from ARF and LD. CBZ sometimes causes ARF or LD, but rarely induces both simultaneously, especially in adults. Pathological evidence of two lesions other than from autopsy seems to be the first step in this case. Cross reaction with other antiepileptic agents was also of interest, suggesting that one member of the cytochrome P450 subfamily, CYP3A, participated in the mechanism.

A novel pathophysiologic phenomenon in cachexic patients with chronic obstructive pulmonary disease: the relationship between the circadian rhythm of circulating leptin and the very low-frequency component of heart rate variability.

Cachexic patients with chronic obstructive pulmonary disease (COPD) show abnormalities of the autonomic nervous system (ANS), neuroendocrine function, and energy expenditure. Leptin has been implicated in the regulation of ANS, neuroendocine function, and thermogenesis in humans. We assessed the physiologic significance of the circadian rhythm of circulating leptin using power spectrum analysis of heart rate variability (HRV) in nine cachexic male patients with COPD, eight noncachexic patients with COPD, and seven healthy control subjects. A diurnal pattern of 24-h leptin levels was present in both the control subjects (analysis of variance [ANOVA]; F = 7.80, p < 0.0001) and noncachexic COPD patients (F = 9.29, p < 0.0001), but was strikingly absent in the cachexic COPD patients (F = 2.09, p = NS). Analysis of HRV demonstrated that the diurnal rhythm of 24-h very low frequency (VLF; 0.003 to 0.04 Hz) showed significantly identical fluctuations with those of 24-h leptin levels, in all of the three groups (r = 0.388, p < 0.0001). Because VLF has been considered to reflect neuroendocrine and thermoregulatory influences, these data may suggest that the loss of circadian rhythm of circulating leptin has clinical importance in the pathophysiologic features in cachexic patients with COPD.

Exposure of RBL-2H3 mast cells to Ag(+) induces cell degranulation and mediator release.

There is a growing need to understand the impact of environmental sulfhydryl group-reactive heavy metals on the immune system. Here we show that Ag(+) induces mast cell degranulation, as does the aggregation of the high affinity immunoglobulin E receptor (FcepsilonRI). Micromolar quantities of Ag(+) specifically induced degranulation of mast cell model rat basophilic leukemia (RBL-2H3) cells without showing cytotoxicity. The Ag(+)-mediated degranulation could be observed as rapidly as 5 min after the addition of the ions. Ag(+) also induced a rapid change in tyrosine phosphorylation of multiple cellular proteins including the focal adhesion kinase but not Syk kinase. The Syk-selective inhibitor piceatannol and the Src family-selective tyrosine kinase inhibitor PP1 dose-dependently inhibited FcepsilonRI-mediated degranulation, whereas neither compound inhibited the Ag(+)-mediated degranulation. Furthermore, likewise FcepsilonRI aggregation, Ag(+) also induced leukotriene secretion. These results show that Ag(+) activates RBL-2H3 mast cells through a tyrosine phosphorylation-linked mechanism, which is distinct from that involved in FcepsilonRI-mediated activation.

Spectral analysis of epicardial 60-lead electrograms in dogs with 4-week-old myocardial infarction.

There were few studies on the spectral analysis of multiple-lead epicardial electrograms in chronic myocardial infarction. Spectral analysis of multi-lead epicardial electrograms was performed in 6 sham-operated dogs (N group) and 8 dogs with 4-week-old myocardial infarction (MI group). Four weeks after the ligation of left anterior descending coronary artery, fast Fourier transform was performed on 60-lead epicardial electrograms, and then inverse transform was performed on 5 frequency ranges from 0 to 250 Hz. From the QRS onset to QRS offset, the time integration of unsigned value of reconstructed waveform was calculated and displayed as AQRS maps. On 0-25 Hz AQRS map, there was no significant difference between the 2 groups. In the frequency ranges of 25-250 Hz, MI group had significantly smaller AQRS values than N group solely in the infarct zone. It was shown that high frequency potentials (25-250 Hz) within QRS complex were reduced in the infarct zone.

Ethnicity and skeletal Class III morphology: a pubertal growth analysis using thin-plate spline analysis.

A longitudinal retrospective study using thin-plate spline analysis was used to investigate skeletal Class III etiology in Japanese female adolescents. Headfilms of 40 subjects were chosen from the archives of the Orthodontic department at Niigata University Dental Hospital, and were traced at IIIB and IVA Hellman dental ages. Twenty-eight homologous landmarks, representing hard and soft tissue, were digitized. These were used to reproduce a consensus for the profilogram, craniomaxillary complex, mandible, and soft tissue for each age and skeletal group. Generalized least-square analysis revealed a significant shape difference between age-matched groups (P < .001), except for the craniomaxillary complex at stage IVA. T test for size analysis showed unequivocally increased mandibular size in skeletal Class III, which directly increased the craniofacial size collectively (P < .05). A deviant profilogram showed anisotropy displaying as maxillary deficiency, acute cranial base, and obtuse gonial angle in addition to increased facial height at stage IIIB. Maxillary retrusion decreased while the mandible showed excessive incremental growth and a forward position caused by deficient orthocephalization at stage IVA. Craniomaxillary complex total spline and partial warps (PW)3 and 2 showed a maxillary retrusion at stage IIIB opposite an acute cranial base at stage IVA. Mandibular total spline and PW4, 5 showed changes affecting most landmarks and their spatial interrelationship, especially a stretch along the articulare-pogonion axis. In soft tissue analysis, PW8 showed large and local changes which paralleled the underlying hard tissue components. Allometry of the mandible and anisotropy of the cranial base, the maxilla, and the mandible asserted the complexity of craniofacial growth and the difficulty of predicting its outcome.

Abnormal distribution of anionic sites in the glomerular basement membrane in glomerulonephritis of dogs infected with Dirofilaria immitis.

Ultrastructural alteration of anionic sites (ASs) in the glomerular basement membrane (GBM) was studied in glomerulonephritis characterized by linear capillary IgG deposition in four dogs infected with Dirofilaria immitis and two normal control dogs using polyethyleneimine. ASs were identified as small dense particles distributed regularly in the lamina rara externa (LRE), but there were no ASs in the lamina densa (LD) of the GBM of the control dogs. In the glomeruli of the infected dogs, ASs were distributed regularly or irregularly in the thickened LD. ASs were in addition localized over the characteristic continuous bands of subendothelial dense deposits. The number of ASs of the LRE increased in all four infected cases as compared to the controls (p<0.01).

Experimental sensitization with Japanese cedar pollen in dogs.

Japanese cedar pollinosis is a type I allergic disease mediated by immunoglobulin E (IgE) antibodies to Japanese cedar (Cryptomeria japonica) pollen antigen (CPAg). By using 22 dogs consisting of 20 dogs aged 3 months and 2 dogs aged 3 years, immunization was performed by subcutaneous injections of CPAg with aluminum hydroxide gel. Variable levels of CPAg-specific IgE antibody response were detected in 21 of the 22 immunized dogs two weeks after the second immunization. This study provided an experimental sensitization system with CPAg in dogs, which will be useful for further immunological studies on Japanese cedar pollinosis.

Diphenyleneiodonium prevents reactive oxygen species generation, tyrosine phosphorylation, and histamine release in RBL-2H3 mast cells.

Mast cells play a central role in immediate allergic reactions mediated by immunoglobulin E. It has recently been reported that mast cells generate intracellular reactive oxygen species (ROS) in response to stimulation with divergent physiologically relevant stimulants. However, the physiological role of ROS is poorly understood. Here we demonstrate that mast cell model rat basophilic leukemia (RBL-2H3) cells generate ROS in response to antigen and the calcium-ionophore A23187 via activation of diphenyleneiodonuim (DPI)-sensitive enzyme and that blockade of ROS generation by DPI suppresses histamine release induced by either stimulant. Increased tyrosine phosphorylation of pp125(FAK) and a 77-kDa protein coprecipitating specifically with the kinase occurred in parallel with the secretion, and blockade of ROS generation by DPI also suppressed the tyrosine phosphorylation of both proteins. These findings suggest that ROS generated by a flavoenzyme-dependent mechanism may be involved in histamine release through the pp125(FAK) pathway.

Dobutamine stress echocardiography for the diagnosis of myocardial viability: assessment of left ventricular systolic velocities in longitudinal axis by pulsed Doppler tissue imaging.

Dobutamine (DOB) stress two-dimensional echocardiography is an established method for the detection of viable myocardium, but conventional assessment of wall motion is subjective. We measured quantitatively the left ventricular systolic velocities along the longitudinal axis by pulsed Doppler tissue imaging (DTI). In 30 patients with previous myocardial infarction, pulsed DTI focused on the infarct area was performed from an apical two- or four-chamber view before and during DOB (10 microg/kg/min) stress one day before coronary angioplasty. We calculated peak systolic velocity (S), regional pre-ejection period (PEP, the time interval from the onset of QRS to the onset of systolic wave) and regional ejection time (ET). Left ventriculography was obtained before and 3 months after coronary angioplasty to assess regional wall motion. Improvement of abnormal wall motion was observed in 19 patients (group P) but not in 11 (group N). Group P had significantly larger S and smaller PEP/ET than group N during DOB stress, although there were no significant differences in these indices between the groups at baseline. As a consequence, group P had a significantly larger percent change in S and a smaller percent change in PEP/ET than group N (164+/-39 vs 117+/-20% and 88+/-17 vs 116+/-29%, respectively, p < 0.01). It is suggested that the quantitative measurement of longitudinal systolic velocities during DOB stress by DTI is useful for the precise assessment of myocardial viability.

Anisotropic effects of sodium channel blockers on the wavelength for ventricular excitation in dogs.

The purpose of this study was to determine the anisotropic effects of sodium channel blockers on wavelength (WL) and proarrhythmia. In 18 anesthetized, open chest dogs, a 64-electrode array was placed on the left ventricle and the ventricle was constantly paced. Disopyramide, lidocaine or flecainide was intracoronarily administered. Conduction velocity (theta) and activation-recovery interval (ARI) were measured in the longitudinal (L) and transverse (T) directions. Flecainide markedly decreased thetaL, but did not alter thetaT or ARIs in either direction. As a result, the wavelength was significantly shortened only in the L direction. Disopyramide or lidocaine did not show direction-dependent effects on theta or WL. In 3 of 6 dogs with flecainide exposure, ventricular fibrillation (VF) developed. However, no VF occurred with disopyramide or lidocaine. Accordingly, the WL is dependent on the fiber orientation of myocardium. The anisotropic shortening of the WL may explain the character of the proarrhythmia observed with flecainide.