Ventricular fibrillation threshold during acute ischemia in hypertrophied rat hearts

Summary Ventricular fibrillation threshold was significantly lower in hypertrophied hearts than in normal hearts. Ischemia produced by coronary occlusion reduced fibrillation threshold in both normal and hypertrophied hearts, but the maximum reduction in fibrillation theshold was observed earlier in hypertrophied hearts.     

Some extracellular matrix elements as markers of 'capillary tunnels' in hypertrophied rat heart.

We studied the distribution of the extracellular matrix proteins fibronectin (FN) and laminin (LM) in the hypertrophied hearts of spontaneously hypertensive rats (SHR), using an immunofluorescence method with specific antibodies. The immunohistochemical reaction was positive in the cytoplasm of some hypertrophied cardiomyocytes. The results showed that FN and LM can be used as markers for tunnels, i.e. intracardiocytic invaginations of the sarcolemma. The tunnels observed contained capillaries.     

Some extracellular matrix elements as markers of ‘capillary tunnels’ in hypertrophied rat heart

We studied the distribution of the extracellular matrix proteins fibronectin (FN) and laminin (LM) in the hypertrophied hearts of spontaneously hypertensive rats (SHR), using an immunofluorescence method with specific antibodies. The immunohistochemical reaction was positive in the cytoplasm of some hypertrophied cardiomyocytes. The results showed that FN and LM can be used as markers for tunnels, i.e. intracardiocytic invaginations of the sarcolemma. The tunnels observed contained capillaries.     

A histochemical study of denervated marsupial hemidiaphragm.

The marsupial (quokka) hemidiaphragm showed postdenervation hypertrophy and subsequent atrophy. The type II muscle fibres hypertrophied up to 20 days postoperation and then regressed. However, the type I fibres hypertrophied throughout the experimental period (100 days) studied. Unlike denervated eutherian hemidiaphragm, fibre-splitting was absent in the denervated marsupial muscle. An enhancement of the ATPase reaction in the denervated type I fibres may be due to dedifferentiation. Presumably innervation exerts a 'negative control' and prevents increase of type I fibre size in the normal hemidiaphragm.     

Minoxidil-induced cardiac hypertrophy in guinea pigs

To investigate whether during cardiac hypertrophy changes occur in contractile protein composition and in mechanical and energetic properties of the myocardium, contractile protein composition, isometric force and adenosine triphosphate (ATP) consumption were studied in control and hypertrophied guinea-pig hearts. Cardiac hypertrophy was induced by adding minoxidil (120 or 200 mg/l) to the drinking water. Protein analysis was performed by one-dimensional gel electrophoresis. The myosin heavy-chain (MHC) composition was determined in an enzyme-linked immunosorbent assay (ELISA). ATP consumption and force development were simultaneously measured during isometric contraction in chemically skinned trabeculae. Histochemical analysis of cross-sectional area of cardiomyocytes and interstitial space was performed on the left ventricular tissue of 200 mg/l minoxidil-treated and control guinea pigs. Minoxidil treatment (120 and 200 mg/l) significantly increased left ventricular dry weight normalized for body weight by 19 ± 4 and 24 ± 4%, respectively. No significant differences were found in the cellular cross-sectional area, while interstitial space was slightly decreased in minoxidil-treated hearts. In left ventricular trabeculae of 200 mg/l minoxidil-treated guinea pigs, ATPase activity was slightly less than in those of control guinea pigs, whereas force did not differ significantly. Calcium sensitivity of force and ATPase activity were not affected by minoxidil treatment. Gel electrophoresis revealed no difference in contractile protein composition, but a tendency towards a lower amount of α-MHC in the minoxidil-treated hearts was found in ELISA. Received 1 February 1999; accepted 15 March 1999     

Interarterielle koronare Anastomosen

Summary Wax spheres with a diameter of 35–45 µ and 75–90 µ were injected into one coronary artery of 73 human hearts. The finding of spheres in the opposite coronary artery was considered as evidence for the presence of interarterial coronary anastomoses. In hearts with occlusive coronary sclerosis or ventricular hypertrophy anastomoses were found in approximately 70% of the cases. Of the 15 normal hearts only 1 (7%) was found to have anastomoses.     

A histochemical study of denervated marsupial hemidiaphragm

Summary The marsupial (quokka) hemidiaphragm showed postdenervation hypertrophy and subsequent atrophy. The type II muscle fibres hypertrophied up to 20 days postoperation and then regressed. However, the type I fibres hypertrophied throughout the experimental period (100 days) studied. Unlike denervated eutherian hemidiaphragm, fibre-splitting was absent in the denervated marsupial muscle. An enhancement of the ATPase reaction in the denervated type I fibres may be due to dedifferentiation. Presumably innervation exerts a negative control and prevents increase of type I fibre size in the normal hemidiaphragm.I am grateful to Dr O.M. Sola and Professor B.A. Kakulas for their help and encouragement.     

Effects of disuse and nerve stump length on the development of fibrillation in denervated soleus muscle

Summary Both in normal (control) and in cordotomized (disused) rats, the soleus muscle was denervated either by cutting the sciatic nerve near the trochanter (proximal denervation) or by cutting the soleus nerve near the insertion into the muscle (distal denervation). In the control muscles, the development of fibrillation was not dependent on the level of nerve section. In disused muscles, the development of fibrillation was greater following distal denervation than following the proximal one.     

Bilinear correlation between tissue water content and diastolic stiffness of the ventricular myocardium

Summary In oedematous and dehydrated canine hearts a close bilinear correlation was demonstrated between myocardial water content and diastolic stiffness (characterized by the passive elastic modulus) with an optimal minimum of stiffness at normal myocardial water content.     

Abnormalities in the development and reproduction of Blattella germanica (L.) (Dictyoptera: Blattellidae) treated with insect growth regulators with juvenile hormone activity

Summary Laboratory populations of German cockroach reared on food treated with R-20458 (75 ppm) or Ro 20-3600 (3000 ppm) became completely sterile and eventually extinct. The hypertrophied oocytes had excessively laid chorion, and the hypertrophied accessory sex glands contained excessive amounts of protein.     

Über den Nukleinsäuregehalt des normalen und hypertrophischen Kaninchenherzens

Summary In left ventricular myocardium of 9 hypertrophic (artificial aortic insufficiency) and 12 normal rabbit hearts, ribonucleic and desoxyribonucleic acids were determined. In hypertrophy DNA-P was significantly reduced, where-as RNA-P was higher than in normal myocardium. The RNA-P/DNA-P ratio was 2·9 in normal as compared to 4·0 in hypertrophic heart muscle.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Effect of glomerulopressin on the lymphatic hearts of the toad,probably mediated by prostaglandins

Summary Glomerulopressin acts on the lymphatic hearts of toads: increasing the passage of T-1824 from the abdominal lymphatic sac to the veins in normal animals, but not in toads treated with indomethacin.     

The influence of salt intake on glomerular count in compensatory kidney hypertrophy in rats of different ages

Summary Drinking saline instead of water elevated the glomerular count in hypertrophied kidneys of rats uninephrectomized as adults. No changes occurred in glomerular concentration in kideny tissue indicating a more marked increase of other kidney structures. This procedure was ineffective in immature animals.     

Das Verhalten des Glykogens bei linksventrikulärer Hypertrophie nach artifizieller peripherer Widerstandserhöhung

Summary By an artificial stenosis of the abdominal aorta, hypertrophy of the left heart is produced. Different degrees of narrowing of the aorta lead to different degrees of heart hypertrophy. After a starvation of 24 h, the glycogen content of the heart that is in a hypertrophic condition is higher than in normal hearts.     

Morphologic alterations induced by aflatoxin B1 in Bacillus thuringiensis (Berliner)]

Significative ultrastructural alterations shown in aflatoxin B1, treated cells of Bacillus thuringiensis are: increase of number of mesosomes which are hypertrophied, decrease of ribosomes and formation of imperfect cell septa.     

Cardiomyocyte growth and sarcomerogenesis at the intercalated disc

Cardiomyocytes grow during heart maturation or disease-related cardiac remodeling. We present evidence that the intercalated disc (ID) is integral to both longitudinal and lateral growth: increases in width are accommodated by lateral extension of the plicate tread regions and increases in length by sarcomere insertion within the ID. At the margin between myofibril and the folded membrane of the ID lies a transitional junction through which the thin filaments from the last sarcomere run to the ID membrane and it has been suggested that this junction acts as a proto Z-disc for sarcomere addition. In support of this hypothesis, we have investigated the ultrastructure of the ID in mouse hearts from control and dilated cardiomyopathy (DCM) models, the MLP-null and a cardiac-specific β-catenin mutant, cΔex3, as well as in human left ventricle from normal and DCM samples. We find that the ID amplitude can vary tenfold from 0.2 μm up to a maximum of ~2 μm allowing gradual expansion during heart growth. At the greatest amplitude, equivalent to a sarcomere length, A-bands and thick filaments are found within the ID membrane loops together with a Z-disc, which develops at the transitional junction position. Here, also, the tops of the membrane folds, which are rich in αII spectrin, become enlarged and associated with junctional sarcoplasmic reticulum. Systematically larger ID amplitudes are found in DCM samples. Other morphological differences between mouse DCM and normal hearts suggest that sarcomere inclusion is compromised in the diseased hearts.     

The effects of salicylate and aspirin on the activity of phosphorylase a in perfused hearts of rats

Summary Sodium salicylate and aspirin are known to have a glycogenolytic effect as judged by either the glycogen level or lactate production in perfused hearts of rats. In this work it was possible to demonstrate that phosphorylase a level was increased in the hearts subjected to the action of these drugs.     

Wiederherstellung des normalen Herzschlages nach elektrisch erzeugtem Kammerflimmern durch Adenosintriphosphorsäure

Summary (1) In the isolated mammalian heart (rabbit, cat, dog) electrically induced ventricular fibrillation is stopped in practically 100% of the cases by adenosin-triphosphoric acid (ATP) in doses of 0.25–20 mg, and the normal rhythm of the heart is permanently restored (as far as the experiment extends).(2) This effect of ATP follows from a primary blocking, which leads to a complete cessation of the activity of the ventricles with diastolic dilatation of the heart.(3) In as much as adenyl acid from yeast and adenosin (in large doses) also stop ventricular fibrillation, the energetic effect of ATP seems to be of no importance in stopping it; it is a specific effect of the adenyl compounds on the bundle ofHis.     

聚焦超声辐照右足三里对痛阈的影响

目的观察聚焦超声辐照正常人右足三里对痛闽的影响。方法40例正常健康人,随机分成聚焦超声辐照组和安慰剂对照组,各20例。聚焦超声辐照右足三里30min,用Electronic Von Frey测定机械痛阈。在聚焦超声辐照前和开始辐照后10、20、30、40、50、60min记录机械痛阈。安慰剂对照组同时进行对比测量。结果超声辐照组,辐照前后左右两侧痛阈值分别有显著性差异（P〈0.01）;对照组,辐照前后左右两侧痛阈值均无统计学意义（左侧P=0．904,右侧P=0．274）。超声辐照组相邻时间水平有显著差异（P〈0．01）,对照组相邻时间水平无显著差异;左右两侧不同部位间无显著性差异（P=0．176）;时间与部位无交互效应（P=0．411）。结论聚焦超声辐照单侧足三里后痛阈明显升高,从而具有一定的镇痛作用。