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The changes in the amount, rate of synthesis and the nucleotide composition of different RNA fractious in excised barley leaves floated on water or kinetic (10 mg/l) in the dark were examined. In excised leaves floated on water all nucleic acid components declined and these declines were retarded by kinetin. Barley leaves floated on water showed a stimulation of 32P incorporation into various RNA fractions within 48 hours followed by a decline after 96-144 hours. The leaves floated on kinetin, however, showed an even higher incorporation of 32P into RNA by 48 hours which remained at a comparatively higher level throughout the experiment. In spite of the above changes in RNA synthesis significant differences in the 32P sucrose gradient profiles or in the 32P nucleotide composition of RNA from water and kinetin floated leaves were not noted. The results of this study show that important changes in nucleic acid metabolism occur during the early stages of leaf senescence and that alterations in nucleic acid metabolism during senescence and during kinetic treatment may involve quantitative and only subtle qualitative changes. [ABSTRACT FROM AUTHOR]

In the guinea pig anaphylatoxin produces mast cell damage that is similar to that produced by antigen-antibody reaction but is different from that produced by chemical histamine liberators. This damage is inhibited by iodoacetate, p­chloromercuribenzoate, phenol and cold, but is not inhibited by calcium lack or previous heating of the tissue to 45° C. Mepyramine reduces but does not abolish the contraction of the ileum produced by anaphylatoxin. Previous heating of a sensitized ileum to 45° C., although completely abolishing the anaphylactic response, does not interfere with the contraction induced by anaphylatoxin. Furthermore desensitization to anaphylatoxin does not modify the anaphylactic contraction. The implication of anaphylatoxin with the anaphylactic reaction is discussed. It is concluded: (a) that anaphylatoxin shares with the anaphylactic reaction part of the pathway leading to histamine release; (b) that the mechanism of action of anaphylatoxin is quite different from that of the chemical histamine liberators. [ABSTRACT FROM AUTHOR]

The article focuses on the seasonal heat resistance limits of the plants in Western Australia and their connection with water deficits, cell sap properties as well as the regeneration ability of heat damaged plants. Based on earlier literature on leaf heat resistance limits for arid and semi-arid regions in Western Australia, semi-succulent and woolly, mesophytic species have higher resistance values compared to Acacia. In 1969, researcher W. Schwarz observed that the heat resistance limit of Pinus cembra and Rhododendron ferrugineum is affected by the prevailing temperature, the daylength and the endogenous rhythm.

The article discusses the dermatological condition known as kerato-acanthoma, including its clinical features, histopathology, and treatment options. The author explains that the tumors consist primarily of an overgrowth of hyperplasmic epithelium, and discusses differences between this condition and squamous carcinoma, including the small degree of atypicality of epithelial cells demonstrated in the former.

Artificial tetraploids of the Linum perenne group closely resemble their diploid progenitors in macroscopic characters, but differ markedly in their pollen morphology. The pollen of the diploids invariably has three furrows, that of the natural tetraploids normally has six pores and that of the artificial tetraploids typically has six furrows. The pollen of the artificial tetraploids is particularly variable because of tendencies towards syncolpy and the asymmetrical arrangement of furrows. The artificial autotetraploids tend to have lower pollen fertilities and more meiotic irregularities than the artificial allotetraploids. None of the artificial tetraploids resembled the natural tetraploid L. perenne subsp. anglicum particularly closely, but its origin is discussed in the light of the available evidence. [ABSTRACT FROM AUTHOR]

Effects of a nonionic surface active agent (lauroyl/myristoyl di (z-hydroxyethyl) amide) and one anionic surfactant (sodium (linear) dodecylbenzene sulphonate) on cell ultrastructure were determined using Pizaloenopsis protocorms. There were no observable effects after 5 days exposure to woo ppm of the nonionic. However, the anionic caused severe damage. Drastic changes in morphology, loss of membranes, swelling of thylakoids and appearance of dense osmophilic granules were evident in chloroplasts. Other effects include disintegration of polysomes into monosomes; swelling of mitochondria; dispersion of chromatin in the nucleus; appearance of unidentified vesicles in the cytoplasm and plasmolysis of cells. These ultra- structural changes can be attributed to the possible emulsification of membrane lipids as well as precipitation and dispersion of cellular proteins. [ABSTRACT FROM AUTHOR]

Defects in thyroid hormone production, transport and utilization are classified. Particular attention is given to inherited intrathyroidal defects in hormone synthesis which impair thyroid function and lead to goitre formation and hypothyroidism. Anomalies in biosynthesis may also result from disease or drugs. Reference is made to the derangement of iodine metabolism that results from iodine deficiency and from insufficient TSH. Illustrative clinical problems with regard to transport and utilization are quoted, and it is inferred that they lie in rather neglected areas. Throughout an attempt has been made to show how the clinical problems that are encountered in practice may, by the techniques of investigation available to us, be related to the theoretical list of defects that are included in the classification. [ABSTRACT FROM PUBLISHER]

, , 488-491. Experience of valve replacement with the Beall compressed Teflon disc valve in 59 patients confirms that the incidence of clinically significant late red cell destruction is high. An apparently previously unrecorded high incidence of early haemolysis, so severe in one patient as to be directly the cause of death, is reported. In 29 patients there was massive haemolysis in early convalescence, not recognized in urine from some hours after the end of bypass and never encountered with other designs of prosthetic valve or homograft valve. [ABSTRACT FROM PUBLISHER]

The article presents a study which evaluates some current practices in undergraduate physiology courses in State Universities. The observation that undergraduate physiology is very diverse and unstandardized, made for an intriguing and interesting problem. By using a questionnaire, the information on current practices and programs in undergraduate animal physiology courses was obtained. The questionnaires revealed that at the graduate level, the opportunity for specialization in physiology is more common and widespread. It was found that there was a great disparity in the numbers of instructional personnel and auxiliary staff that are available for physiology programs. The introductory vertebrate physiology and introductory human physiology courses are the commonest offering in the four-semester credit course. The findings reveal that another advanced course that is prevalent at the undergraduate level is cell physiology. According to the study, undergraduate physiology courses offered by state universities disclose a great diversity and disparity between institutions, with considerable individuality in the manner of educating students in physiology.

The basic heritable physiologic mechanism of man and other vertebrates consists of neurovascular stimulus response activities in which afferent impulse potential is redirected in the terminal neuron, by presynaptic axon reflex for uninhibited antidromic conduction, to within the walls of nutrient arterioles for vasodilation diffusion of oxygen and other hemic substances to provide Cell excitation, function, metabolism, rehabilitation, and reproduction. Many pathophysiologic disease processes develop in response to prolonged overstimulation of afferent potential, and to peripheral reflex vasodilation diffusion of excess neurokinin and other hemic substances that result in nutrient arterial perivascular interstitial edematous inflammatory degenerative and proliferative activities in the walls of arteries, nerves, and other tissue, and accelerated cell activities beyond their tolerance, while predominating over the associated inhibiting acitivities and inputs in contributing to unbalanced homeostasis. The abnormal manifestations include neuritis, arteritis, arteriosclerosis, anoxia, mucus epithelial hyperplasia' and metaplasia, decalcification, dystrophy and dysfunction, muscle degeneration, joint instability, pain, lowered stimulation threshold, and impaired neural conduction and reflexes. Identification and elimination of the etiologic factors responsible for prolonged noxious stimulation attain reversal of physiologic unbalanced mechanism, elimination of pain, and the resumption of normal activities. [ABSTRACT FROM AUTHOR]

The article focuses on some of the molecular mechanisms involved in the regulation of cell function and offers a conceptual framework on the categories of all potential molecular control mechanisms. It talks about the regulation of the general levels of cellular flow of information as a way to systematically deal with achieving cell regulation. The four basic levels at which control can be exerted include the transcription of genetic information from DNA to RNA, the translation of information from RNA to protein, direct modification of a protein's activity, and degradation of protein.

The article presents information about the study "Some Characteristic and Biological Functions of the Skin Surface," conducted by M.B. Sulzberger and F. Herrmann. The very thin, topmost layer of the skin, which not so long ago was looked upon as lifeless and inert, actually encompasses a great many highly intricate and complex physico-chemical systems exercising a variety of integrated and vitally important functions. Practically all these functions aid the body's defence against exogenous or endogenous insults--and virtually all show some patterns of homeostasis.