Morphometry of the heart of greater rhea (Rhea americana americana,Linnaeus, 1758)

Heart diseases in birds are frequent and generate significant production disorders. Morphometry is a valuable tool to provide fundamental information about heart conditions. Few studies have addressed morphological aspects of the heart of ratite birds, such as the Greater rhea. The present study aimed to analyse rhea heart morphometry, comparing young and adult subjects, in order to provide relevant information for the diagnosis of heart disease in this species. Hearts of young (n = 10) and adult (n = 10) female rheas were used in this research. Heart length and width and sternum length were measured using a caliper. Heart length and width and sternum length in adults were approximately three times greater than in young individuals. The left ventricular wall (LVW) was thicker than the right ventricular wall (RVW) at all ages, and the RVW was thicker in adults when compared to young subjects. The basal and middle RVW regions thicken with advancing age, and the thickness of the interventricular septum (ISW) occupies an intermediate position between the LVW and RVW. In general, an increase in rhea heart thickness and size relative to age is observed. The morphometric variations between young and adult rhea hearts observed in the present study may serve as a comparative subsidy for the diagnosis of cardiac abnormalities observed in this species.     

Age- and sex-dependent regression models for predicting the live weight of West African Dwarf goat from body measurements

The relationships between live weight and eight body measurements of West African Dwarf (WAD) goats were studied using 211 animals under farm condition. The animals were categorized based on age and sex. Data obtained on height at withers (HW), heart girth (HG), body length (BL), head length (HL), and length of hindquarter (LHQ) were fitted into simple linear, allometric, and multiple-regression models to predict live weight from the body measurements according to age group and sex. Results showed that live weight, HG, BL, LHQ, HL, and HW increased with the age of the animals. In multiple-regression model, HG and HL best fit the model for goat kids; HG, HW, and HL for goat aged 13–24 months; while HG, LHQ, HW, and HL best fit the model for goats aged 25–36 months. Coefficients of determination (R ²) values for linear and allometric models for predicting the live weight of WAD goat increased with age in all the body measurements, with HG being the most satisfactory single measurement in predicting the live weight of WAD goat. Sex had significant influence on the model with R ² values consistently higher in females except the models for LHQ and HW.     

Changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and association with racing performance

OBJECTIVE: To evaluate changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and determine whether there was any relationship between cardiac dimensions and racing performance. DESIGN: Longitudinal observational study. ANIMALS: 103 horses. PROCEDURE: 2-dimensional and M-mode echocardiography was performed 4 times at 6-month intervals. RESULTS: Significant cardiac enlargement took place during the study period as indicated by increases in left ventricular internal diameter in diastole (LVIDd), estimated left ventricular muscle mass (LV mass), and mean wall thickness attributable to eccentric left ventricular hypertrophy. Estimated body weight was positively correlated with left ventricular size, and males had significantly larger LVIDd and LV mass than did females. Horses that were racing regularly had larger LVIDd and LV mass than did unraced horses. A significant relationship between left ventricular size and racing performance was observed. The relationship was strongest at the time of the fourth examination. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that age must be taken into account when interpreting results of echocardiography in young Standardbred racehorses because significant cardiac enlargement takes place with age and training. A larger heart was found in horses that were racing, and size of the heart was correlated with athletic performance of the horse.     

Effect of genotype, sex and rearing temperature on carcase and meat quality of guinea fowl

1. The aim of our study was to analyse the effect of genotype (label and standard), sex and rearing temperature (simulating daily outdoor in the summer or winter) on the carcase and meat quality of guinea fowl. Using 20 animals per treatment, slaughtered at 96 d of age we measured the breast angle and the thickness of the skin on the wing membrane. Carcases were weighed and cut into parts according to a standardised procedure to determine the percentages of abdominal fat, breasts, wings and thighs with shanks. 2. At slaughter, standard guinea fowl were heavier than label guinea fowl and for both genotypes, the females were heavier than the males (+5.6%). The mean value of breast angle was 85 degrees. This value was significantly higher for the standard guinea fowls and for the females of both genotypes compared with males. Thus, female carcases, particularly standard females, were more compact. The skin was thicker for the standard guinea fowls (0.84 mm vs 0.77 mm) which could be due to more subcutaneous fat. 3. Carcase yield was higher for the males (68.7% vs 68.2%). The percentage of abdominal fat was higher for the standard guinea fowls (2.8% vs 2.4%) and for the females of both genotypes compared with males. The label guinea fowls had higher yields of breasts and thighs with shanks. For both lines, the breast and thigh meat of females was judged more tender and less stringy. 4. Low rearing temperature decreased growth performance but had no significant effect on carcase quality.     

M-MODE ECHOCARDIOGRAPHIC PARAMETERS AND INDICES IN THE NORMAL GERMAN SHEPHERD DOG

M-mode echocardiographic measurements were made from 50 healthy German Shepherd dogs (30 males and 20 females). The dogs were awake and unsedated, in right lateral recumbent position. The following parameters were measured on the echocardiographic images: interventricular septal thickness at end-diastole (IVSd), interventricular septal thickness at end-systole (IVSs), left ventricular internal dimension at end-diastole (LVIDd), left ventricular internal dimension at end-systole (LVIDs), left ventricular posterior wall thickness at end-diastole (LVPWd), left ventricular posterior wall thickness at end-systole (LVPWs), left atrial dimension (LAD), aortic root dimension (AOD), left atrial to aortic root ratio (LAD/AOD), right ventricular internal dimension at end-diastole (RVID), amplitude of mitral valve excursion (DE amplitude), velocity of mitral valve opening (D-E slope), and velocity of mitral valve closure (E-F slope). Fractional shortening (FS) was also calculated. The effect of gender and age on each echocardiographic parameter was analyzed and the relationship between body weight (BW) and each parameter was also investigated. There was a significant relationship between gender and LVPW in systole and diastole and FS. Significant association was also found between BW and IVS, LVID, and LVPW in systole and diastole, FS, LAD, AOD, RVID, DE amplitude, and D-E slope of the mitral valve.     

Ultrasonographic appearance of the coelomic cavity in healthy green iguanas

OBJECTIVE: To describe the ultrasonographic appearance of the coelomic cavity in healthy green iguanas. DESIGN: Cross-sectional study. ANIMALS: 26 healthy green iguanas (20 males and 6 females). PROCEDURES: For coelomic ultrasonography, animals were physically restrained in dorsal recumbency by an assistant; chemical restraint was not used. Qualitative and quantitative observations were recorded. RESULTS: Structures that could be visualized in all animals included the heart and cardiac chambers; liver; caudal vena cava; hepatic veins; portal vein; gallbladder; pyloric portion of the stomach; and, when distended, urinary bladder. Visualization of the kidneys was poor. The spleen could be identified in 17 animals, and the gonads could be identified in 22, but were most easily identified in males evaluated during November (ie, during the breeding season); no females were evaluated during the breeding season. Physiologic enlargement of the testes yielded an acoustic window for the spleen by displacing overlying intestine. Anechoic, free coelomic fluid was identified in 3 animals. Measurements of overall cardiac size, ventricular wall thickness, gallbladder size, thickness of the pyloric portion of the stomach, and splenic size were obtained. Only ventricular wall thickness was significantly correlated with body weight. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that ultrasonography allowed examination of most coelomic structures in green iguanas. The procedure was easily performed and was well tolerated in conscious animals.     

Echocardiographic ratio indices in overtly healthy Boxer dogs screened for heart disease

BACKGROUND: Boxer dogs are routinely screened by echocardiography to exclude congenital and acquired heart disease. Individuals of a given breed may span a large range of body sizes, potentially invalidating linear regression of M-mode measurements against body weight. Echocardiographic ratio indices (ERIs) provide a novel method of characterizing echocardiographic differences between Boxers and other dog breeds. HYPOTHESIS: ERIs obtained from overtly healthy Boxer dogs presented for cardiac screening will be different from ERIs established for normal non-Boxer dogs, and those differences will be unrelated to aortic velocity or systolic blood pressure. ANIMALS: Eighty-one Boxers with no outward clinical signs of heart disease were studied. METHODS: All dogs were examined by 2-dimensional, M-mode, and Doppler echocardiography. M-mode measurements were used to perform ERI calculations, and the indices in Boxers were compared between Boxers with varying severity of arrhythmia and those of normal non-Boxer dogs. RESULTS: Differences in weight-based ERIs, which reflect increased thickness of the left ventricular free wall (LVW) and interventricular septum (IVS) and smaller aortic size, were found in overtly healthy Boxer dogs compared with normal non-Boxer dogs. ERIs of left atrial and LV cavity size in overtly healthy Boxers were not significantly different from those of non-Boxer dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Boxer dogs may have an increased relative thickness of the LVW and IVS that is independent of aortic size, aortic velocity, or arterial blood pressure, and this morphology should be taken into consideration when screening Boxers by echocardiography.     

Comparison of echocardiographic and autopsy measurements of cardiac dimensions in the horse

This study was initiated to determine the accuracy of M-mode echocardiography in measuring left ventricular dimensions and estimating heart weights in horses. Left ventricular free wall and interventricular septal thickness and left ventricular external and internal diameters were measured and heart weights estimated from the echocardiograms of 47 horses. Autopsy measurements of the same parameters were then recorded. Statistical comparison of the data demonstrated: (1) Systolic measurements of wall thickness more closely resembled the heart in death than the diastolic measurements; (2) good correlations existed between parameters measured echocardiographically and at autopsy, especially wall thicknesses and left ventricular external diameter (maximum r = 0.82); (3) heart weight was readily predicted from echocardiographic wall thickness regressions (maximum R-squared = 68 per cent). M-mode echocardiography demonstrated the potential for direct and accurate measurements of cardiac mass and some ventricular dimensions in the horse. The data suggested that intense rigor and exsanguination may render the autopsied heart unsatisfactory for comparative measurements when assessing techniques such as echocardiography.     

A quantitative study of cardiac ventricular mass in dogs.

This study was undertaken to determine the correlations between heart weight, ventricular weight and body weight in adult dogs. A total of 130 dogs was selected for the study after necropsy and histological examination. The body weights (BW) were obtained and a standardized dissection technique was used to obtain the total heart weight (HW), total ventricular mass (VW), right ventricular mass (RvW) and the left ventricular plus the interventricular septum mass (Lv + SW). A strong and significant correlation was found between all variables (BW, HW, VW, Lv + SW and RvW). The following ratios were calculated: HW/BW, RvW/BW, Lv + SW/BW, RvW/VW, Lv + SW/VW, RvW/HW, Lv + SW/HW and Lv + SW/RvW. No sex effect was observed on any ratios. A straight linear relationship was observed between HW and Lv + SW or RvW and between Lv + SW and RvW. The ratios Lv + SW/HW, RvW/HW and Lv + SW/RvW could then be used to predict a normal value of Lv + SW or RvW from a known HW value, or a normal value of Lv + SW from a known RvW value. The relations between BW and HW, Lv + SW or RvW were best described by second order equations. Such equations should be utilized to predict a normal value of HW, Lv + SW or RvW from a known BW value.     

Two-dimensional and M-mode echocardiographic measurements of cardiac dimensions in healthy standardbred trotters

The aim of the study was to establish normal echocardiographic values of healthy Standardbred trotters not published previously. Twenty-three clinically normal horses weighing between 350 and 490 kg were examined in the same manner: first a thorough physical and then detailed echocardiographic examination were performed. Standardised two-dimensional (2D) and guided M-mode echocardiographic imaging techniques were used to measure interventricular septal thickness (IVS), left ventricular internal diameter (LVID), left ventricular wall thickness (LVW), left atrial internal diameter (LAID) in end-systole (s) and end-diastole (d) and aortic diameter (AOD) in end-diastole. Mean, range and standard deviation of the different parameters were calculated. The mean values (in centimetres) were as follow (2D/M-mode): IVSs: 4.6/4.7; IVSd: 3.1/3.0; LVIDs: 7.0/7.0; LVIDd: 10.7/10.7; LVWs: 3.9/3.9; LVWd: 2.7/2.7; LAIDs: 10.4/-; LAIDd: 11.3/-; AODd: 7.2/-. Results of two-dimensional and M-mode measurements were compared to each other and to normal values obtained from other breeds.     

Heterogeneity of Hypertrophy in Feline Hypertrophic Heart Disease

Eighty-six cats with non-dilated left ventricular myocardial hypertrophy were studied retrospectively. Cats were categorized by two-dimensional echocardiography as having symmetric ventricular hypertrophy (Type I), asymmetric with predominant septal thickening hypertrophy (Type II), and asymmetric hypertrophy with predominant free-wall thickening (Type III). The distribution of hypertrophy was judged subjectively and objectively. Subjective and objective results were similar (P= 0.03) although overlap existed between groups. Morphologic patterns (Types I, II, and III) were compared with breed, age, sex, heart rate, percent fractional shortening, left atrial size, serum creatinine concentration, and the presence (yes/no) of pleural effusion, pulmonary edema, pericardial effusion, heart murmur, dyspnea, thromboembolism, hyperthyroidism, and being alive at the time of study. Interventricular septal thickness, left ventricular free wall thickness, percent fractional shortening, and left atrial size additionally were compared to 3-month survival. Cats with Type HI hypertrophy were more likely to experience thromboembolism than cats with Type II hypertrophy (P= 0.05) and cats with Type I hypertrophy were more likely to have heart murmurs than cats with Type III (P= 0.02). No other significant associations were found in comparison to pattern of hypertrophy. Both left atrial size and percent fractional shortening significantly correlated with 3-month survival (P < 0.001 for each). The degree of interventricular septal wall thickness was associated with 3-month survival (P= 0.02) when known hyperthyroid cats were excluded from the study group, while left ventricular free wall thickness consistently was not associated with survival. This study demonstrates the heterogeneity of hypertrophy in cats with hyper-trophic heart disease and provides predictors of survival (left atrial size, percent fractional shortening, and interventricular septal wall thickness when compared with euthanasia/spontaneous death data).     

Twenty-Four-Hour Ambulatory Electrocardiography in Normal Cats

Twenty-four-hour ambulatory electrocardiograms were recorded in two age groups of 10 normal cats each: group 1 (1 to 4 years) and group 2 (8 to 14 years), with equal numbers of males and females in each group. Average heart rates over the 24-hour recording period ranged from 114 to 202 beats/minute (bpm). The mean 24-hour average rate did not differ between group 1 and group 2 (157.6 vs. 156.3+/-5.3 bpm, respectively); however, females (both groups combined) had higher average heart rates than males (166.8 vs. 147.1+/-5.3 bpm, respectively). Females also had a higher mean minimum heart rate than males (116.9 vs. 96.5+/-4.2 bpm, respectively); but there were no gender or age group differences in maximum heart rate. Results of hourly analyses of average, minimum, and maximum heart rates were similar. Mean heart rates rose from mid-afternoon to about 9:00 PM and were lowest just after midnight. Although regular sinus rhythm predominated, periods of sinus arrhythmia were evident in most cats, especially in early morning hours. Supraventricular extrasystoles were uncommon. Isolated ventricular extrasystoles occurred more frequently in group 2 cats; multiform configuration was observed in both groups. Repetitive ventricular extrasystoles, which usually consisted of occasional couplets, occurred more frequently in group 2 cats. One older cat had 2 short runs of ventricular tachycardia. Another older cat appeared to have a recurrent accelerated idioventricular rhythm.     

Reference Values and Repeatability of B-Mode and M-Mode Echocardiographic Parameters in Healthy Donkey (Equus asinus)—The Guide to Assess Healthy Heart

Donkey (Equus asinus), the cheapest form of agricultural power in Egypt, is used principally as draught or pack animals and may also be ridden, or used for threshing, raising water, milling, and other work. The aim of the present study was to provide B-mode and M-mode echocardiographic reference ranges from a sample of population of donkeys (E. asinus) based on the probability theory and statistics. In the present study, B-mode and 2-dimensional guided M-mode echocardiography were performed on 44 clinically healthy donkeys (E. asinus) (22 males and 22 females), without any neither clinical nor echocardiographic evidence of cardiovascular diseases, aged 2–25 year old, and weighed 150–350 kg. The echocardiographic dimensions, including interventricular septum thickness at end diastole, interventricular septum thickness at end systole, left ventricular internal diameter at end diastole, left ventricular internal diameter at end systole, left ventricular posterior wall thickness at end diastole, and left ventricular posterior wall thickness at end systole were assessed. The cardiac function indices, including end diastolic volume, end systolic volume, stroke volume, ejection fraction, and fractional shortening were also measured. B-mode and guided M-mode echocardiographic examination of healthy donkeys revealed that both the interventricular septum thickness and the left ventricular posterior free wall were greater during systole than diastole. However, the left ventricular dimension during diastole was greater than systole. Furthermore, the recorded data of cardiac function indices, including end diastolic volume, end systolic volume, stroke volume, ejection fraction, and fractional shortening using B-mode echocardiography were closer to those recorded by guided M-mode echocardiography. To our knowledge, this is the first Egyptian study to report the echocardiographic reference ranges of donkeys (E. asinus) based on the probability theory and statistics, the coefficient of variation. The results of the present study can be used as standard and reference values for further echocardiographic studies in donkeys and represent a step in the identification, interpretation, and evaluation of cardiovascular disorders in such animals.     

Echocardiographic characteristics of chickens with ascites syndrome

1. B- and M-mode echocardiography was used to compare cardiac function in broilers with spontaneous ascites syndrome with that of normal chickens. 2. Thirty ascitic chickens and 15 normal chickens aged three, 4, 5, and 6 weeks from the same flock (180 birds in total) were examined. They were restrained gently in a natural standing position, and echocardiographs were obtained from a 7.0-MHz linear transducer placed on the left pectoral apterium. Indices of cardiac structure and functioning were calculated from the echocardiographs, and some were normalised to body weight. Heart rate was also measured. 3. All cardiac structural indices in both ascitic and normal chickens increased with age. Compared with normal chickens, right ventricular diameter at the end of systole in ascitic chickens was greater at 4, 5 and 6 weeks of age. Ventricular septal thickness at the end of both systole and diastole was greater in ascitic chickens at 5 and 6 weeks. Left ventricular free wall thickness at the end of diastole was less in ascitic chickens at 3 weeks. However, all the structural indices decreased with age after normalisation with body weight. 4. The heart rate of ascitic chickens was lower at 4, 5 and 6 weeks. Normalised left ventricular fractional shortening was lower in ascitic chickens at 4, 5 and 6 weeks, as was normalised right ventricular fractional shortening. Incrassation of the ventricular septum (Delta T), which changed little in normal chickens, was less at 4, 5 and 6 weeks in ascitic chickens. Left ventricular fractional shortening, right ventricular fractional shortening and Delta T were all negatively correlated with ascites heart index at all ages. 5. Taken together the results suggest heart failure of both ventricle, but that right ventricular dysfunction is more extensive than left ventricular dysfunction. We suggest that secondary pulmonary hypertension would result in these ascitic chickens due to volume overload.     

Relationship of Echocardiographic Measurements and Velocity at Maximum Heart Rate Measured During Prerace Training Period in Thoroughbred Horses

The objective of this study was to investigate in Thoroughbreds, the relation between the development of the heart at prerace period and the velocity at maximum heart rate (VHRmax) between the 24th and 28th month before starting to race. Twenty-one Thoroughbreds (11 female, 10 male) were used in this study. The echocardiographic data were obtained from the short-axis view in guided M-mode, at 4-month intervals until the 24th month after birth. The VHRmax was measured monthly from the 24th to the 28th month by E-Trakka. Linear regression analyses were performed between echocardiographic parameters and VHRmax values at 24 and 28 months after birth. The results indicated that left ventricular internal diameter in diastole at 12 months (LVIDD₁₂) tended to be negatively correlated with VHRmax measured at the 24th month (P = .098). However, ejection fraction (EF₁₂) (P = .061) and fractional shortening (FS₁₂) (P = .056) values tended to be positively correlated with VHRmax measured at the 24th month (VHRmax₂₄). There was a tendency toward negative correlation between interventricular septal thickening percentage (IVST%) measured 1 month after birth and VHRmax measured at the 28th month (VHRmax₂₈) (P = .079). In contrast, there were positive correlations between mean wall thickness of 4 months (MWT₄), relative wall thickness of 4 months (RWT₄), and VHRmax₂₈ (P < .05). EF₁₆ and FS₁₆ tended to be correlated with VHRmax₂₈. Furthermore, EF and FS parameters measured in 20 months after birth (EF₂₀ and FS₂₀) were correlated with VHRmax₂₈ (P < .05). There was a tendency toward a positive correlation between the left ventricular muscle mass of horses at 24 months of age (LVM₂₄) and VHRmax₂₈ (P = .097). In addition, mean wall thickness of 24 (MWT₂₄) months and relative wall thickness of 24 months (RWT₂₄) were significantly correlated with VHRmax₂₈ (P < .05). In this study, we observed a relationship between some echocardiographic parameters measured during developmental period and VHRmax measured during prerace training period. Because VHRmax is related to athletic potential, echocardiographic parameters measured at early ages may be used as selection criteria.     

Echocardiographic parameters of captive western lowland gorillas (Gorilla gorilla gorilla)

A total of 163 echocardiographic studies on western lowland gorillas (Gorilla gorilla gorilla) were submitted for evaluation; 140 from 99 animals were suitable for analysis. Of these, 81 studies (42 studies from 35 males ranging in age from 11-41+ yr and 39 studies from 31 females ranging in age from 11-41+ yr) are reported here. Three studies from 3 females and 56 studies from 30 males were excluded from this report due to cardiac abnormalities. Cardiac parameters measured were aortic root (Ao Rt) diameter and left atrial (L atrium) size. Left ventricular (LV) measurements included left ventricular internal diameter in systole (LVID(s)) and diastole (LVID(d)) as well as diastolic septal (IVS) and posterior wall thickness (LVPW). Values considered to be normal in females > 11 yr of age were: Ao Rt < 3.5 cm, L atrium < 4.0 cm, LVID(d) < 5.0 cm, IVS < 1.4 cm, LVPW < 1.4 cm, and ejection fraction (EF) > 60%. The data from male gorillas show a separation in animals based on three cardiac parameters: systolic function, LV cavity size, and LV wall thickness. Male gorillas > 11 yr of age fall into two groups; unaffected and affected. Unaffected animals are defined as those with no echocardiographic abnormalities and a consistent Ao Rt of < 4.0 cm, LVID(d) of < 6.0 cm, IVS and LVPW of <1.5 cm, and an EF of > 58%. The affected group consisted of male gorillas that exhibited changes in echocardiographic parameters representing the presence of cardiovascular disease. The results determined in this database, gathered from data collected from 1999-2009, suggest a sex-based difference between males and females with predominantly males demonstrating evidence of cardiac disease. The most striking finding seen in this study is that of progressive LV hypertrophy and depressed LV EF in affected adult male gorillas.     

Contractile activity of cultured adult Dirofilaria immitis

A method for long-term maintenance of adult heartworms (HW) in culture for use in contractile activity studies was developed. Culture conditions included Eagle's minimum essential medium (MEM) containing Earle's balanced salt solution and MEM vitamins and supplemented with 10% horse serum, pH 7.6, 37 degrees C, and humidified 5% CO2:95% room air atmosphere. Motility was observed for up to 91 days. Reducing the culture atmosphere from 20% oxygen to 5% oxygen reduced acid production and survival to 28 days or less. Spontaneous contractile activity of adult HW coils (1 cm diameter) was measured using an isometric force displacement transducer system. Activity had an arrhythmic pattern of good magnitude that could be recorded after up to 50 days in culture for male HW and after up to 40 days in culture for female HW. Analyses of contractile activity included determination of its amplitude, frequency, contraction index, and basal tension. Amplitude for males (3.4 +/- 1.2 g) (mean +/- S.D.) was significantly greater (P < 0.02) than that for females (3.0 +/- 1.1 g), whereas frequency for females (8.2 +/- 2.3 min) was significantly greater (P < 0.03) than that for males (7.5 +/- 2.3 min). The contraction index for females was 16.7 +/- 13.7 mm/min and for males, 14.4 +/- 9.0 mm/min. The difference was not significant. The contraction index was based on line integration of the record of contractile activity. Amplitude and frequency of contractile activity for anterior segments (2.5 cm), suspended lengthwise, from cultured adult female HW, were not significantly different from results for coils, but the contraction index (34.5 +/- 33.8) was significantly higher (P < 0.01) indicating that the pattern of activity was more uniform in the segments. An applied basal tension of about 4 g was suitable for the coils, while a suitable basal tension for segments was about 1.5 g. For coils, amplitude, frequency, and contraction index increased significantly (P < 0.02) with increase in basal tension. Coils were not sensitive to changes in ionic, glucose, oxygen, and osmol concentrations, and pH (6.8-7.6) of the bathing solution. A pH of 8.0 markedly increased basal tension and contractile activity. At 20 degrees C contractile activity stopped. These effects of pH and temperature were reversible. The HW appeared resistant to changes in their environment. This is probably related to an efficient cuticular barrier. The culture and recording methods used in this study open improved opportunities for quantitative evaluation of responsiveness of HW to a variety of physiological and pharmacological factors.     

扬子鳄的年龄鉴定技术

在2003年3月~2005年3月间,分4次对0.5~6.5年龄段已知年龄的人工饲养的扬子鳄头长(HL)、头宽(HW)、吻眼间距(SE)和眼间距(EE)这4个头部形态参数和体长进行测量。在所测量的各年龄段中,鳄的体长范围互有重叠,不适合作为鳄年龄鉴定的指标。以体长作为协变量的协方差分析表明:头长在0.5龄与2.5龄间(P=0.173)无显著性差异,头宽在0.5龄与1.5、2.5和3.5龄间(P=1.171、P=1.013、P=1.533)以及1.5龄与2.5龄间(P=0.159)无显著性差异;而头长和头宽在其他年龄段间,以及吻眼间距和眼间距在所有年龄段间均有极显著性差异;同一批鳄生长一年后,即1.5龄长到2.5龄,2.5龄长到3.5龄,4.5龄长到5.5龄,其头部形态的4个参数都有显著性变化,而在不同年份生长的同龄鳄间,如在1.52、.5和5.5龄的同龄鳄间,其吻眼间距都存在显著性差异,头长和头宽在2.5和5.5龄时具有显著性差异,眼间距却都无显著性差异,保持着稳定的状态;在同龄的不同性别鳄中,如4.5龄的雌雄鳄间,眼间距无显著性差异,即该参数不存在性别的差异。经比较分析显示,扬子鳄的年龄不宜通过体长、头长、头宽和吻眼间距等参数进行确定,而与眼间距值存在着对应关系。这一研究结果为野生扬子鳄种群的结构变化建立动态模型,为野生扬子鳄的性成熟年龄及生育年龄做出准确的判断,对鳄的引种贸易和科研中的样本筛选等具有重要的指导作用。     

M-MODE ECHOCARDIOGRAPHIC REFERENCE VALUES IN CATS IN THE FIRST THREE MONTHS OF LIFE

Thirty-five young cats were studied by echocardiography from the 2nd to 12th weeks of life to analyze correlation between body weight, body surface area, age and heart rate with fourteen echocardiographic parameters. There was a positive linear correlation (r = 0.49-0.78) between the independent variables (body weight, body surface area, age) and left ventricular wall thickness and diameter, aortic diameter and left atrial diameter, whereas there was a negative correlation (r = -0.39 and r = -0.43) between the heart rate and left ventricular diameter during systole and diastole. No linear dependence of the fractional shortening, ejection fraction, percentage thickening of the interventricular septum and left ventricular posterior wall, LA/AO ratio, and the ratio IVSED/LVWED to the independent variables was observed.     

The effect of hypothyroidism on cardiac function in dogs

The thyroid hormones have direct and indirect effects on the heart. So it is possible that depression of left ventricular function is associated with hypothyroidism. This publication describes cardiac findings (auscultation, electrocardiography, echocardiography) in ten hypothyroid dogs. Low heart rates, reduced R-amplitudes and bradycardic arrhythmias (first and second-degree AV block) were found on the electrocardiogram before treatment. On the echocardiograms most of the dogs showed reduced contractillity and reduced left ventricular wall thickness. Seven dogs were reexamined after levothyroxine supplementation. Effects of treatment were increased heart rates and R-amplitudes as well as disappearance of the bradycardic arrhythmias in electrocardiographic examination. The echocardiographic examination showed increased contractility and increased left ventricular wall thickness.