The effect of age on cardiac output and its distribution in the rat

Summary Cardiac output distribution in the rat was found to be affected by age. Cardiac index and blood flow to the liver, kidneys, skin and skeletal muscle were lower in 11–12 month compared to 3–4 month old rats.Acknowledgments. This work was supported by grants from I.C.I. Pharmaceuticals and Mersey Regional Health Authority (Research Scheme No.338). We wish to thank Mr P.J. Roberts for invaluable technical assistance.     

Cardiac hypertrophy accelerated by left cervical sympathectomy in spontaneously hypertensive rats

Summary Cardiac hypertrophy in spontaneously hypertensive rats was accelerated by denervation of the left cervical sympathetic ganglia. Supersensitivity due to denervation may also exist in cardiac muscles.This work was supported by a grant of the Ministry of Education for 1980.     

Seasonal variations of cardiac output in rats.

Cardiac output of rats shows seasonal variations with low values in spring and summer and high ones in autumn and winter. The stroke volume was much more implicated in these changes than the heart rate. The seasonal changes of cardiac output are probably due to changes of thyroid function.     

Beziehung zwischen Nebenniere und aktivem Kationentransport

Summary The active sodium transport through the membrane of coldstored red cells of adrenalectomised rats is significantly decreased, whereas the rate of active exchange of potassium is not influenced by adrenalectomy. Cardiac glycosides likewise slow down only the active sodium exchange in the blood of both the normal and adrenalectomised animals in contrast to their action on human red cells.     

Cathétérisme intracardiaque en clinique

Summary Cardiac catheterization, initially conducted byForssmann in 1929, has become a qualified clinical method. A fine rubber catheter is introduced into the antecubital vein and mechanically reaches the right heart chambers; auricular and ventricular, as well as the pulmonary artery. In some exceptional cases the left auricle and ventricle likewise lend themselves to exploration.     

An examination of factors contributing to delphi accuracy

Three experiments examined the accuracy in the Delphi method. The first experiment assessed the accuracy of group predictions over 1-, 2- and 3- month time spans. Results indicated that predictions derived from the group were more accurate than those of 95 per cent of the individual panelists, but did not exceed in accuracy the best panelists. Experiment 2 evaluated the gross contributions of polling and feedback to Delphi accuracy. The manipulations did not improve the group's ability to forecast the probabilities of the occurrence of events, but did decrease the error in predicting when the events would occur. Experiment 3 separated the effects of polling and feedback as determinants of accuracy. Neither manipulation improved the accuracy of the group's predictions of whether an event would occur. The effect of iterated polling was to reduce the group's error in predicting the time course for those scenarios that did occur.     

Veränderungen der thermoelastischen Kontraktion von Haut und Nerv bei alternden Tieren

Summary The thermo-elastic contraction which has been found to increase with age in the tendons, has been studied in the skin. This shows a contraction between 64–66°C similar to that of tendon fibres. In 22 month old rats, it reaches 5–6 times greater values than in 3 month old animals. The skin also shows a second contraction between 67 and 70°C. After the ninth month, in a continuously increasing degree, a third and fourth step of contraction appear at higher temperatures (up to 82°C).The sciatic nerve also shows a thermo-elastic contraction after the fourth month at 76–80°C. This increases with age, and, as in the case with the skin, several more steps of contraction appear at higher temperatures, up to 92°C. It is improbable that these thermo-elastic contractions are related to «elastin». The changes with increasing age, however, show a similarity to the age changes of «elastin» in so far as the thermic contractility increases with age.     

Immunological aspects of 22q11.2 deletion syndrome

Chromosome 22q11 deletion is the most common chromosomal deletion syndrome and is found in the majority of patients with DiGeorge syndrome and velo-cardio-facial syndrome. Patients with CHARGE syndrome may share similar features. Cardiac malformations, speech delay, and immunodeficiency are the most common manifestations. The immunological phenotype may vary widely between patients. Severe T lymphocyte immunodeficiency is rare—thymic transplantation offers a new approach to treatment, as well as insights into thymic physiology and central tolerance. Combined partial immunodeficiency is more common, leading to recurrent sinopulmonary infection in early childhood. Autoimmunity is an increasingly recognized complication. New insights into pathophysiology are reviewed.     

Forecasting the Italian industrial production index in real time

Daily electricity consumption data, available almost in real time, can be used in Italy to estimate the level of industrial production in any given month before the month is over. We present a number of procedures that do this using electricity consumption in the first 14 days of the month. (This is an extension of a previous model that used monthly electricity data.) We show that, with a number of adjustments, a model using half-monthly electricity data generates acceptable estimates of the monthly production index. More precisely, these estimates are more accurate than univariate forecasts but less accurate than estimates based on monthly electricity data. A further improvement can be obtained by combining ‘half-monthly’ electricity-based estimates with univariate forecasts. We also present quarterly estimates and discuss confidence intervals for various types of forecasts.     

Veränderungen der thermoelastischen Eigenschaften von Sehnenfasern beim Altern

Summary Tendons of the tail of white rats show a thermoelastic contraction after the fifth month of age which appears suddenly at 64–66°C. It is not seen in animals of 3–4 months old. After the nineteenth month, and especially in 27 to 33 month old rats, this contraction becomes much increased. It is supposed that this phenomenon expresses changes in the structure of elastin in ageing animals.     

Variation in the number and size of myelinated nerve fibers regenerated after repeated localized freezing of the sciatic nerve of rats]

The number and size of myelinated fibres have been determined in the nerve to medial head of the gastrocnemius muscle of Rats in which the sciatic nerve had been frozen locally 1 to 5 times at monthly intervals. The contralateral nerve was used as a control. When the measurements were made one month after the last freezing, the number of fibres increased progressively until the 3rd freezing, reaching about 220% of the normal value. No higher values were observed after 4 or 5 freezings. The mean diameter of fibres decreased with the number of operations. When the measurements were made 3, 6, 12 or 18 months after the 3rd freezing, the number of fibres decreased by about 30% between the 1st and the 3rd month and then stabilized. The mean diameter of fibres increased progressively. However, at the 18th month, the size of the myelinated fibres had not reached the normal value.     

A molecular view of cardiogenesis

Cardiac development involves a complex integration of subcellular processes into multicellular and, finally, whole organ effects. Until recently it has been difficult to investigate the genetic control of this organ level differentiation of the heart. The proliferation of molecular biology methodologies has provided mechanisms to directly investigate the control of these processes. This article focuses on molecular lines of research on two key areas in cardiac development: the regulation of expression of sarcomeric contractile and regulatory proteins, and atrial natriuretic factor. Molecular approaches are described which have allowed investigators to begin to determine the tissue and stage-specific expression of genes, to locate those genes in the genome, determine their sequences, and to directly investigate the mechanisms controlling their expression.     

Adenosine is a sensitive oxygen sensor in the heart

Cardiac adenosine is formed both by an oxygen-sensitive (AMP----adenosine) and by an oxygen-insensitive (S-adenosylhomocysteine----adenosine) pathway. The phasic adenosine release during beta-adrenergic stimulation with isoproterenol is closely linked to coronary venous PO2 (isolated heart) and can be almost fully prevented when diastolic aortic pressure is maintained constant (heart in situ). During pressure autoregulation the transmural gradient of free adenosine is only increased when the autoregulatory reserve is exhausted. The critical PO2 below which adenosine formation is enhanced was found to be 3 mm Hg (isolated cardiomyocytes). Collectively, these data indicate that the formation of adenosine is not primarily coupled to the energy expenditure of the heart but to the supply/demand ratio for oxygen.     

Modifications in the type distribution of muscle fibers induced by repeated local freezings the rat sciatic nerve]

In the Rat, after a localized freezing of the sciatic nerve inducing a complete denervation of the medial head of the gastrocnemius muscle, the reinnervation took place within 16-18 days under our experimental conditions. After only one freezing, a limited and stable "type-grouping" of muscle fibres is observed from 30 to 360 days. After 2 to 5 freezing repeated every three weeks, the muscular changes observed one month after the last freezing are much more pronounced than when only one freezing is performed. These changes consist of a progressive increase in the number of type I and type II C fibres. This transformation is not stable: 3 months after the 3rd freezing, the muscle pattern does not differ from that which is noted after a single freezing.     

Certain biochemical effects of garlic oil on rats maintained on high fat-high cholesterol diet

The feeding of a high fat-high cholesterol (HF-HC) diet to normal rats for 1 month increased the lipid components cholesterol and triglyceride in serum, liver and kidneys and decreased the serum albumin very significantly. Administration of garlic oil (100 mg/kg b. wt/day) for 1 month together with the HF-HC diet to another group almost nullified the lipid-increasing and albumin-decreasing effects of that diet. The reduction in total lipids, cholesterol and triglycerides and the restoration to normal level of serum albumin were highly significant in the garlic oil group. Adipose tissue triglyceride lipase activity was significantly increased in both the above groups with a much greater rise in the oil group.     

Certain biochemical effects of garlic oil on rats maintained on high fat-high cholesterol diet

Summary The feeding of a high fat-high cholesterol (HF-HC) diet to normal rats for 1 month increased the lipid components cholesterol and triglyceride in serum, liver and kidneys and decreased the serum albumin very significantly. Administration of garlic oil (100 mg/kg b. wt/day) for 1 month together with the HF-HC diet to another group almost nullified the lipid-increasing and albumin-decreasing effects of that diet. The reduction in total lipids, cholesterol and triglycerides and the restoration to normal level of serum albumin were highly significant in the garlic oil group. Adipose tissue triglyceride lipase activity was significantly increased in both the above groups with a much greater rise in the oil group.     

International equity flows and the predictability of US stock returns

We examined the link between international equity flows and US stock returns. Based on the results of tests of in‐sample and out‐of‐sample predictability of stock returns, we found evidence of a strong positive (negative) link between international equity flows and contemporaneous (one‐month‐ahead) stock returns. Our results also indicate that an investor, in real time, could have used information on the link between international equity flows and one‐month‐ahead stock returns to improve the performance of simple trading rules. Copyright © 2007 John Wiley & Sons, Ltd.     

Die DNS-synthese im rattenherzen als funktion des lebensalters. Autoradiographische untersuchungen mit3H-thymidin

Summary The percentage of DNA-synthesising heart muscle nuclei of white rats (³H-thymidine, autoradiography) decreases rapidly during the first month of life reaching a minimum at the fourth month. From then up to 27 months the number of labelled muscle nuclei remains rather constant. Also in nuclei of connective tissue the³H-thymidine labelling index decreases as a function of the rats age. The number of mitotic figures is always about 10 times lower than labelled nuclei. Mostly in heart muscle cells they occur as collapsed mitoses never leading to cytoplasma division¹⁴.     

Enhancement of vertebrate cardiogenesis by a lectin from perivitelline fluid of horseshoe crab embryo

Cardiac myocytes are the first cells to differentiate during the development of a vertebrate embryo. A wide variety of molecules take part in various steps in this process. While exploring biologically active molecules from marine sources, we found that a constituent of perivitelline fluid from embryos of the Indian horseshoe crab can enhance growth and differentiation of chick embryonic heart. We have purified the factor and identified the cardiac promoting molecule to be a novel lectin. We show that this molecule influences cardiac development by increasing the number of cells constituting the heart and by modulating the expression of several cardiac development regulatory genes in chick embryos. Using mouse embryonic stem cells we show that the cardiac myocyte-enhancing capacity of this molecule extends to mammals and its effects can be blocked using methylated sugars. This molecule may prove to be an important tool in the study of cardiomyocyte differentiation.