Resistance Training After Myocardial Infarction in Rats: Its Role on Cardiac and Autonomic Function

Background: Although resistance exercise training is part of cardiovascular rehabilitation programs, little is known about its role on the cardiac and autonomic function after myocardial infarction. Objective: To evaluate the effects of resistance exercise training, started early after myocardial infarction, on cardiac function, hemodynamic profile, and autonomic modulation in rats. Methods: Male Wistar rats were divided into four groups: sedentary control, trained control, sedentary infarcted and trained infarcted rats. Each group with n = 9 rats. The animals underwent maximum load test and echocardiography at the beginning and at the end of the resistance exercise training (in an adapted ladder, 40% to 60% of the maximum load test, 3 months, 5 days/week). At the end, hemodynamic, baroreflex sensitivity and autonomic modulation assessments were made. Results: The maximum load test increased in groups trained control (+32%) and trained infarcted (+46%) in relation to groups sedentary control and sedentary infarcted. Although no change occurred regarding the myocardial infarction size and systolic function, the E/A ratio (-23%), myocardial performance index (-39%) and systolic blood pressure (+6%) improved with resistance exercise training in group trained infarcted. Concomitantly, the training provided additional benefits in the high frequency bands of the pulse interval (+45%), as well as in the low frequency band of systolic blood pressure (-46%) in rats from group trained infarcted in relation to group sedentary infarcted. Conclusion: Resistance exercise training alone may be an important and safe tool in the management of patients after myocardial infarction, considering that it does not lead to significant changes in the ventricular function, reduces the global cardiac stress, and significantly improves the vascular and cardiac autonomic modulation in infarcted rats.

Male Gender and Arterial Hypertension are Plaque Predictors at Coronary Computed Tomography Angiography

Background: Systemic Arterial Hypertension (SAH) is one of the main risk factors for Coronary Artery Disease (CAD), in addition to male gender. Differences in coronary artery lesions between hypertensive and normotensive individuals of both genders at the Coronary Computed Tomography Angiography (CCTA) have not been clearly determined. Objective: To Investigate the calcium score (CS), CAD extent and characteristics of coronary plaques at CCTA in men and women with and without SAH. Methods: Prospective cross-sectional study of 509 patients undergoing CCTA for CAD diagnosis and risk stratification, from November 2011 to December 2012, at Instituto de Cardiologia Dante Pazzanese. Individuals were stratified according to gender and subdivided according to the presence (HT +) or absence (HT-) of SAH. Results: HT+ women were older (62.3 ± 10.2 vs 57.8 ± 12.8, p = 0.01). As for the assessment of CAD extent, the HT+ individuals of both genders had significant CAD, although multivessel disease is more frequent in HT + men. The regression analysis for significant CAD showed that age and male gender were the determinant factors of multivessel disease and CS ≥ 100. Plaque type analysis showed that SAH was a predictive risk factor for partially calcified plaques (OR = 3.9). Conclusion: Hypertensive men had multivessel disease more often than women. Male gender was a determinant factor of significant CAD, multivessel disease, CS ≥ 100 and calcified and partially calcified plaques, whereas SAH was predictive of partially calcified plaques.

Testosterone Deficiency Increases Hospital Readmission and Mortality Rates in Male Patients with Heart Failure

Background:Testosterone deficiency in patients with heart failure (HF) is associated with decreased exercise capacity and mortality; however, its impact on hospital readmission rate is uncertain. Furthermore, the relationship between testosterone deficiency and sympathetic activation is unknown.Objective:We investigated the role of testosterone level on hospital readmission and mortality rates as well as sympathetic nerve activity in patients with HF.Methods:Total testosterone (TT) and free testosterone (FT) were measured in 110 hospitalized male patients with a left ventricular ejection fraction < 45% and New York Heart Association classification IV. The patients were placed into low testosterone (LT; n = 66) and normal testosterone (NT; n = 44) groups. Hypogonadism was defined as TT < 300 ng/dL and FT < 131 pmol/L. Muscle sympathetic nerve activity (MSNA) was recorded by microneurography in a subpopulation of 27 patients.Results:Length of hospital stay was longer in the LT group compared to in the NT group (37 ± 4 vs. 25 ± 4 days; p = 0.008). Similarly, the cumulative hazard of readmission within 1 year was greater in the LT group compared to in the NT group (44% vs. 22%, p = 0.001). In the single-predictor analysis, TT (hazard ratio [HR], 2.77; 95% confidence interval [CI], 1.58–4.85; p = 0.02) predicted hospital readmission within 90 days. In addition, TT (HR, 4.65; 95% CI, 2.67–8.10; p = 0.009) and readmission within 90 days (HR, 3.27; 95% CI, 1.23–8.69; p = 0.02) predicted increased mortality. Neurohumoral activation, as estimated by MSNA, was significantly higher in the LT group compared to in the NT group (65 ± 3 vs. 51 ± 4 bursts/100 heart beats; p < 0.001).Conclusion:These results support the concept that LT is an independent risk factor for hospital readmission within 90 days and increased mortality in patients with HF. Furthermore, increased MSNA was observed in patients with LT.

The Effect of Sleep Deprivation on Cardiac Function and Tolerance to Ischemia-Reperfusion Injury in Male Rats

Abstract Background: Sleep deprivation (SD) is strongly associated with elevated risk for cardiovascular disease. Objective: To determine the effect of SD on basal hemodynamic functions and tolerance to myocardial ischemia-reperfusion (IR) injury in male rats. Method: SD was induced by using the flowerpot method for 4 days. Isolated hearts were perfused with Langendorff setup, and the following parameters were measured at baseline and after IR: left ventricular developed pressure (LVDP); heart rate (HR); and the maximum rate of increase and decrease of left ventricular pressure (±dp/dt). Heart NOx level, infarct size and coronary flow CK-MB and LDH were measured after IR. Systolic blood pressure (SBP) was measured at start and end of study. Results: In the SD group, the baseline levels of LVDP (19%), +dp/dt (18%), and -dp/dt (21%) were significantly (p < 0.05) lower, and HR (32%) was significantly higher compared to the controls. After ischemia, hearts from SD group displayed a significant increase in HR together with a low hemodynamic function recovery compared to the controls. In the SD group, NOx level in heart, coronary flow CK-MB and LDH and infarct size significantly increased after IR; also SD rats had higher SBP after 4 days. Conclusion: Hearts from SD rats had lower basal cardiac function and less tolerance to IR injury, which may be linked to an increase in NO production following IR.

Estudos experimentais sôbre a origem do milho

1) It may seem rather strange that, in spite of the efforts of a considerable number of scientists, the problem of the origin of indian corn or maize still has remained an open question. There are no fossil remains or archaeological relics except those which are quite identical with types still existing. (Fig. 1). The main difficulty in finding the wild ancestor- which may still exist - results from the fact that it has been somewhat difficult to decide what it should be like and also where to look for it. 2) There is no need to discuss the literature since an excellent review has recently been published by MANGELSDORF and REEVES (1939). It may be sufficient to state that there are basically two hypotheses, that of ST. HILAIRE (1829) who considered Brazilian pod corn as the nearest relative of wild corn still existing, and that of ASCHERSON (1875) who considered Euchlaena from Central America as the wild ancestor of corn. Later hypotheses represent or variants of these two hypotheses or of other concepts, howewer generally with neither disproving their predecessors nor showing why the new hypotheses were better than the older ones. Since nearly all possible combinations of ideas have thus been put forward, it har- dly seems possible to find something theoretically new, while it is essential first to produce new facts. 3) The studies about the origin of maize received a new impulse from MANGELSDORF and REEVES'S experimental work on both Zea-Tripsacum and Zea-Euchlaena hybrids. Independently I started experiments in 1937 with the hope that new results might be obtained when using South American material. Having lost priority in some respects I decided to withold publication untill now, when I can put forward more concise ideas about the origin of maize, based on a new experimental reconstruction of the "wild type". 4) The two main aspects of MANGELSDORF and REEVES hypothesis are discussed. We agree with the authors that ST. HILAIRE's theory is probably correct in so far as the tunicata gene is a wild type relic gene, but cannot accept the reconstruction of wild corn as a homozygous pod corn with a hermaphroditic tassel. As shown experimentally (Fig. 2-3) these tassels have their central spike transformed into a terminal, many rowed ear with a flexible rachis, while possessing at the same time the lateral ear. Thus no explanation is given of the origin of the corn ear, which is the main feature of cultivated corn (BRIEGER, 1943). The second part of the hypothesis referring to the origin of Euchlaena from corn, inverting thus ASCHERSON's theory, cannot be accepted for several reasons, stated in some detail. The data at hand justify only the conclusion that both genera, Euchlaena and Zea, are related, and there is as little proof for considering the former as ancestor of the latter as there is for the new inverse theory. 5) The analysis of indigenous corn, which will be published in detail by BRIEGER and CUTLER, showed several very primitive characters, but no type was found which was in all characters sufficiently primitive. A genetical analysis of Paulista Pod Corn showed that it contains the same gene as other tunicates, in the IV chromosome, the segregation being complicated by a new gametophyte factor Ga3. The full results of this analysis shall be published elsewhere. (BRIEGER). Selection experiments with Paulista Pod Corn showed that no approximation to a wild ancestor may be obtained when limiting the studies to pure corn. Thus it seemed necessary to substitute "domesticated" by "wild type" modifiers, and the only means for achieving this substitution are hybridizations with Euchlaena. These hybrids have now been analysed init fourth generation, including backcrosses, and, again, the full data will be published elsewhere, by BRIEGER and ADDISON. In one present publication three forms obtained will be described only, which represent an approximation to wild type corn. 6) Before entering howewer into detail, some arguments against ST. HILAIRE's theory must be mentioned. The premendelian argument, referring to the instability of this character, is explained by the fact that all fertile pod corn plants are heterozygous for the dominant Tu factor. But the sterility of the homozygous TuTu, which phenotypically cannot be identified, is still unexplained. The most important argument against the acceptance of the Tunicata faetor as wild type relic gene was removed recently by CUTLER (not yet published) who showed that this type has been preserved for centuries by the Bolivian indians as a mystical "medicine". 7) The main botanical requirements for transforming the corn ear into a wild type structure are stated, and alternative solutions given. One series of these characters are found in Tripsacum and Euchlaena : 2 rows on opposite sides of the rachis, protection of the grains by scales, fragility of the rachis. There remains the other alternative : 4 rows, possibly forming double rows of female and male spikelets, protection of kernels by their glumes, separation of grains at their base from the cob which is thin and flexible. 8) Three successive stages in the reconstruction of wild corn, obtained experimentally, are discussed and illustrated, all characterized by the presence of the Tu gene. a) The structure of the Fl hybrids has already been described in 1943. The main features of the Tunicata hybrids (Fig. -8), when compared with non-tunicate hybrids (Fig. 5-6), consist in the absence of scaly protections, the fragility of the rachis and finally the differentiation of the double rows into one male and one female spikelet. As has been pointed out, these characters represent new phenotypic effects of the tunicate factor which do not appear in the presence of pure maize modifiers. b) The next step was observed among the first backcross to teosinte (Fig. 9). As shown in the photography, Fig. 9D, the features are essencially those of the Fl plants, except that the rachis is more teosinte like, with longer internodes, irregular four-row-arrangement and a complete fragility on the nodes. c) In the next generation a completely new type appeared (Fig. 10) which resembles neither corn nor teosinte, mainly in consequence of one character: the rachis is thin and flexible and not fragile, while the grains have an abscission layer at the base, The medium sized, pointed, brownish and hard granis are protected by their well developed corneous glumes. This last form may not yet be the nearest approach to a wild grass, and I shall try in further experiments to introduce other changes such as an increase of fertile flowers per spikelet, the reduction of difference between terminal and lateral inflorescences, etc.. But the nature of the atavistic reversion is alveadwy such that it alters considerably our expectation when looking for a still existing wild ancestor of corn. 9) The next step in our deductions must now consist in an reversion of our question. We must now explain how we may obtain domesticated corn, starting from a hypothetical wild plant, similar to type c. Of the several changes which must have been necessary to attract the attention of the Indians, the following two seem to me the most important: the disappearance of all abscission layers and the reduction of the glumes. This may have been brought about by an accumulation of mutations. But it seems much more probable to assume that some crossing with a tripsacoid grass or even with Tripsacum australe may have been responsible. In such a cross, the two types of abscission layer would be counterbalanced as shown by the Flhybrids of corn, Tripsacum and Euchlaena. Furthermore in later generations a.tu-allele of Tripsacum may become homozygous and substitute the wild tunicate factor of corn. The hypothesis of a hybrid origin of cultivated corn is not completely new, but has been discussed already by HARSHBERGER and COLLINS. Our hypothesis differs from that of MANGELSDORF and REEVES who assume that crosses with Tripsacum are responsible only for some features of Central and North American corn. 10) The following arguments give indirects evidence in support of our hypothesis: a) Several characters have been observed in indigenous corn from the central region of South America, which may be interpreted as "tripsacoid". b) Equally "zeoid" characters seem to be present in Tripsacum australe of central South-America. c) A system of unbalanced factors, combined by the in-tergeneric cross, may be responsible for the sterility of the wild type tunicata factor when homozygous, a result of the action of modifiers, brought in from Tripsacum together with the tuallele. d) The hybrid theory may explain satisfactorily the presence of so many lethals and semilethals, responsible for the phenomenon of inbreeding in cultivated corn. It must be emphasized that corn does not possess any efficient mechanism to prevent crossing and which could explain the accumulation of these mutants during the evolutionary process. Teosinte which'has about the same mechanism of sexual reproduction has not accumulated such genes, nor self-sterile plants in spite of their pronounced preference for crossing. 11) The second most important step in domestication must have consisted in transforming a four rowed ear into an ear with many rows. The fusion theory, recently revived byLANGHAM is rejected. What happened evidently, just as in succulent pXants (Cactus) or in cones os Gymnosperms, is that there has been a change in phyllotaxy and a symmetry of longitudinal rows superimposed on the original spiral arrangement. 12) The geographical distribution of indigenous corn in South America has been discussed. So far, we may distinguish three zones. The most primitive corn appears in the central lowlands of what I call the Central Triangle of South America: east of the Andies, south of the Amazone-Basin, Northwest of a line formed by the rivers São Prancisco-Paraná and including the Paraguay-Basin. The uniformity of the types found in this extremely large zone is astonishing (BRIEGER and CUTLER). To the west, there is the well known Andian region, characterized by a large number of extremely diverse types from small pop corn to large Cuszco, from soft starch to modified sweet corn, from large cylindrical ears to small round ears, etc.. The third region extends along the atlantic coast in the east, from the Caribean Sea to the Argentine, and is characterized by Cateto, an orange hard flint corn. The Andean types must have been obtained very early, and undoubtedly are the result of the intense Inca agriculture. The Cateto type may be obtained easily by crosses, for instance, of "São Paulo Pointed Pop" to some orange soft corn of the central region. The relation of these three South American zones to Central and North America are not discussed, and it seems essential first to study the intermediate region of Ecuador, Colombia and Venezuela. The geograprical distribution of chromosome knobs is rapidly discussed; but it seems that no conclusions can be drawn before a large number of Tripsacum species has been analysed.

Uma nova modalidade de sexo-determinação no grilo sul-americano eneoptera surinamensis

The male of Eneoptera surinamensis (Orthoptera-Eneopteridae) is provided with 9 chromosomes, that is, with 3 pairs of autosomes and 3 sex chromosomes. Spermatogonia. - The autosomes of the spermatogonia are of the same size and U-shaped. One of the sex chromosomes approximately equalling the autosomes in size is telocentric, while the other two are much larger and V-shaped. One of the latter is smaller than the other. The sex chromosomes as showed in Figs. 1 and 2 are designated by X, Yl and Y2, X being the larger V, Yl the smaller one and Y2 the rod-shaped. Primary spermatocytes. - Before the growth period of the spermatocytes all the three sex chromosomes are visible in a state of strong heteropycnosis. X is remarkable in this stage in having two long arms well separated by a wide commissural segment. (Figs. 4, 5 and 6). During the growth period Y2 disappears, while X and Yl remain in a condensed form until metaphase. These may be separated from one another or united in the most varied and irregular manner. (Fig. 7 to 12). In the latter case the segments in contact seem to be always different so that we cannot recognize any homology of parts in the sense os genetics. At diplotene Y2 reappears together with the autosomal tetrads. X and Yl may again be seen as separate or united elements. (Figs. 13 and 14). At later diakinesis and metaphase the three sex chromosomes are always independent from each other, Y2 being typically rod-shaped, X and Yl V-shaped, X being a little larger than Yl. (Fig. 15 to 18). At metaphase the three condensed tetrads go to the equatorial plane, while the sex chromosomes occupy any position at both sides of this plane. In almost all figures which could be perfectly analysed X appeared at one side of the autosomal plate an Yl together with Y2 far apart at the other side. (Figs. 16 and 18). Only a few exception have been found. (Figs. 17 and 19). At anaphase X goes in precession to one pole, Yl and Y2 to the other (Figs. 20 and 21). As it is suggested by the few figures in which a localization of the sex chromosomes different from the normal has been observed, the possibility of other types of segregation of these elements cannot be entirely precluded. But, if this does happen, the resulting gametes should be inviable or give inviable zygotes. Early in anaphase autosomes and sex chromosomes divide longitudinally, being maintained united only by the kinetochore. (Figs. 20 and 21). At metaphase the three sex chromosomes seem to show no special repulsion against each other, X being found in the proximity of Yl or Y2 indifferently. At anaphase, however, the evidences in hand point to a stronger repulsion between X on the one side and both Ys on the other, so that in spite of the mutual repulsion of the latter they finish by going to the same pole. Secondary spermatocytes. - At telophase of the primary spermatocytes all the chromosomes enter into distension without disappearing of view. A nuclear membrane is formed around the chromosomes. All the chromosomes excepting Y2 which has two arms, are four-branched. (Fig. 22). Soon the chromosomes enter again into contraction giving rise to the secondary metaphase plate. Secondary spermatocytes provided as expected with four and five chromosomes are abundantly found. (Figs. 23 and 24). In the former all chromosomes are X-shaped while in the latter there is one which is V-shaped. This is the rod- shaped Y2. In the anaphase of the spermatocytes with four chromosomes all the chromosomes are V-shaped, one of them (X) being much larger than the others. In those with five there is one rod-shaped chromosome (Y2). (Fig. 25), Spermatids. Two classes of spermatids are produced, one with X and other with Yl and Y2. All the autosomes as well as Y2 soon enter into solution, X remaining visible for long time in one class and Yl in the other. (Figs. 26 and 27). Since both are very alike at this stage, one cannot distinguish the two classes of spermatids. Somatic chromosomes in the famale. - In the follicular cells of the ovary 8 chromosomes were found, two of which are much larger than the rest. (Figs. 29 and 30). These are considered as being sex chromosomes. CONCLUSION: Eneoptera surinamensis has a new type of sex-determining mechanism, the male being X Yl Y2 and the female XX. The sex chromosomes segregate without entering into contact at metaphase or forming group. After a review of the other known cases of complex sex chromosome mechanism the author held that Eneoptera is the unique representative of a true determinate segregation of sex chromosomes. Y2 behaving as sex chromosome and as autosome is considered as representing an intermediary state of the evolution of the sex chromosomes.

Contribuição a história natural do «Pararu» Scardafella squammata squammata(Lesson) (1)

The main wild doves of the region of Piracicaba (State of S. Paulo, Brazil) are Columba cayennensis sylvestris Vieillot, Oreopeleia montana montana (L.), Leptotila verreauxi decipiens Salvadori, Columbigallina talpacoti talpacoti. (Temminck) and Scardafella squammata squammata (Lesson). The last one is well known for the beauty of the coloration of its feathers and for the characteristic sounds produced when flying up. Of common occurrence around the local farms, that species can easily be recognized not only for the mentioned peculiarities as for the voice of the adults, which was translated into the Brazilian onomatopoeia by the expression "fogo-apagou". S. squammata's biology being not well known, the Author presents some notes on its nidification, behaviour of both sexes and of the young birds. The data were gotten in nature and with specimens kept in captivity, where the reproduction took place. In such a situation, the male dove used thin and small wooden shavings to build the nest, an artificial material unknown by him when in nature. This fact may be considered as another proof of the plasticity of the instinctive conduct of birds, not so marked as the one given by SCHIRCH (1931) concerning Synallaxis sp. (Furnariidae), which made use of wire pieces and also barbed wires in confectioning the nest. The copulation was sometimes verified, being preceded by the phenomena well known in other Columbidae species. The nest had its building ready just on the day in which the first egg was laid. As it generally happens amongst doves, the nest was not carefully made - a simple and shallow bowl (diameter = 10 cm), where two entirely white eggs were put.. .. ..(22,5-24,5 x 18,0-19,0 mm). The eclosion took place 14 days after the laying of the last egg. As soon as the young doves (at least the male one) can feed by themselves, they try to produce the characteristic species sounds. "Pararu", a common name oly applied to another species - Claravis godefrida (Temminck) - is reported, which is preferably used by people in this region to call the studied dove. No differences between the coloration of the fathers of the two sexes were observed. The female dove seemed to be a little thinner than the male. In addition, the slight differences between the sounds produced by the male and female are pointed out.

Male-female interaction during breeding and non-breeding seasons in Akodon azarae (Rodentia, Muridae)

Dyad encounters between male and female adults of Akodon azarae (Fischer, 1829) were analyzed by means of observational techniques in a natural closure during the breeding and non-breeding seasons. The animals were held in observation during 21 days, with daily 15-minute recordings of interindividual separation distance, relative displacements, characteristics of the male-female interaction, copulation, and construction and exclusive or shared use of nests by each pair. The couples, which bred successfully, showed, on average, the longest separation distance between male and female allowed by the closure. During the first two weeks of gestation the females exhibited more displacements than their respective mates did. The male-pregnant female encounters were significantly more aggressive than those recorded between pairs which did not breed successfully. During the non-breeding season a shorter average distance between individuals and a frequent use of nests shared by the pair were recorded. The results obtained are discussed within the framework of the social system of A. azarae.

Description of the male of Hypognatha belem (Araneae, Araneidae)

The male of Hypognatha belem Levi, 1996 is described and illustrated for the first time. New records expand the distribution range of the species to northeastern and southeastern Brazil.

Skull morphometrics of adult male Antartic fur seal, Arctocephalus gazella, and South American fur seal A. australis

The skull morphometrics of adult male Antarctic fur seal, Arctocephalus gazella (Peters, 1875) and South American fur seal, A. australis (Zimmermann, 1783) were investigated using a collection of 45 and 38 skulls, respectively. Eighteen measurements were taken for each specimen. Comparative univariate and multivariate statistical analyses included standard statistics, one-way analysis of variance, principal component analysis and discriminant analysis. Individual variation was relatively high for some variables, as expressed by the coefficient of variation. Skulls of A. gazella were larger than those of A. australis for all but two variables: squamosal jugal suture and rostral length. Both species differed significantly as shown by both univariate and multivariate analyses. The discriminant function correctly classified all specimens. The standardized canonical coefficients showed that the variables which most contribute to the differentiation between species were, in decreasing order, the rostral length, palatal length, palatal width at postcanine 5 and braincase width. The present study corroborates that A. gazella and A. australis are phenotipically distinct species.