Degree Of Starvation Research Articles

Effect of starvation and prednisolone administration on collagen and calcium metabolism in mature rats.

Male rats more than 11/2 years of age were injected with45Ca2+. Some were starved for 4, 9, and 15 days beginning one day later. Others were starved beginning 35 days after receiving the label, and still others were injected with prednisolone until 30% weight loss was induced, although the latter did not receive45Ca2+. In the starved animals, weight losses of 10–12%, 20–22%, and 30–32% were induced. These groups lost 13%, 16%, and 28%, respectively, of their carcass nitrogen while the prednisolone group lost 29%. The femora of these animals exhibited no collagen loss. Calcium in the femora was significantly reduced (8% loss) in the animals starved the most. In the carcass (minus the femora, skin, lungs, and small intestine) collagen was reduced 4%, 7%, and 15% in the starved groups and 11% in the cortisone group while calcium was reduced 6%, 5%, 18%, and 13%, respectively. The c.p.m. and s.a. of calcium in the animals which received the isotope and were starved immediately, were considerably greater than that of the controls, increasing with degree of starvation and was greater in the carcass than in the femora. When starvation was instituted 35 days after administration of isotope, the patterns were similar but the relative increase was far below the previous. The results were interpreted as follows: 1. Collagen in the femora is stable in the presence of great loss of body nitrogen induced by starvation or prednisolone administration. However, in the carcass large decrements may result under these conditions. 2. Small amounts of calcium may be lost without loss of collagen, but with large losses, collagen is lost in roughly equal proportion to calcium. 3. Newly-laid-down calcium becomes altered with time in its chemical or thermodynamic state so that it responds differently in the presence of starvation than it did before.

Effect of Food Quantity on Fecundity of Rainbow Trout, Salmo gairdneri

Studies of histology and development of rainbow trout ovaries indicate that the degree of follicular atresia is associated with degree of starvation during the maturation period. Experimental stocks raised under varying starvation regimes showed that the greater the starvation, the higher the proportion of maturing follicles which regressed. Thus the result was a lower number of eggs brought to maturity in starved fish.Observations on natural populations indicate wide differences in egg size, with corresponding inverse differences in egg number at maturity. Egg size is apparently not effected by diet, but rather through natural selection depending on intraspecific competition. There appeared to be little correlation between egg size and fish size, but some difference did exist between age classes. Variations in egg number are therefore attributable to fish size, egg size and adequacy of diet. Starvation has also a lasting effect on the proportion of a given age-class which matures.

Differences revealed by paper partition chromatography between the gastropod Nassarius reticulatus (L.) and specimens believed to be N. nitida (Jeffreys)

SUMMARYThe ninhydrin-positive patterns produced by chromatography of foot tissue of Nassariics reticulatus from Plymouth and North Wales and of specimens of Nassarius from Essex were established. The similarities and differences between the two are described and the consistent differences found are considered to be indicative of genetic differences between the specimens from Essex and those from the other two areas. The only factor found to affect the otherwise remarkably reproducible pattern given by individuals from the same area was the degree of starvation; the effect was reversible. The pattern given by another marine gastropod, Littorina littorea (L.), is also described. Reference is made to the potentialities of the technique.

Alcohol in intravenous feeding.

Some degree of starvation is a common and accepted sequel to severe injury, and for several days after major operations patients usually lose their appetite and do not eat. In the past attempts have been made to avoid this period of starvation by means of intravenous feeding with protein hydrolysates and various sources of energy. Close examination of the normal response to injury shows, however, that the well-nourished patient has an inherent capacity to survive injury and starvation and to heal his wounds, that after injury the organism so orders its economy that it provides from its own substance the raw materials for the repair of injured tissues as well as the daily energy requirements. The present tendency is thus once more to leave the body as much as possible to its own rather inscrutable devices during the postoperative period. This attitude means that the potential field for intravenous feeding, including the administration of alcohol, has again contracted to the few states in which a patient is unable to ingest or digest food by the alimentary tract. The value of parenteral nutrition is rather uncertain but there may be some place for it in the treatment of patients with fistulas of the small intestine, ulcerative colitis, advanced malnutrition and some forms of hepatic disease. Originally a 5 or 6% solution of amino-acids derived from the acid or enzymic hydrolysis of milk protein was combined with a source of energy such as glucose. The success of intravenous feeding with protein depends, however, on the provision of an adequate accompaniment of calories, which has given rise to most practical difficulties. An uninjured healthy person lying in bed probably requires about 2100 Cal./day, but this basal requirement is increased after injury and by other forms of inflammation (Cuthbertson, 1945). To supply 2100 Cal. would entail the daily infusion of over 11 1. of 5%) or 5.6 1. of 10%) glucose solution. Even normal subjects have only a limited tolerance for repeated large intravenous infusions; after injury and in inflammation of all kinds this tolerance is greatly reduced and, apart from the replacement of losses of body fluids, not more than 2.5 l./day can be safely administered. Emulsions containing up to 30% of fat have been developed and administered intravenously and are safe and satisfactory sources of calories but have a limited stability or ‘shelf-life’. A 15% fat emulsion would provide 1200 Cal. /l. but, unfortunately, is still not commercially available. These various difficulties in providing adequate supplies of energy to accompany or ‘cover’ infusions of protein

VII.—On Migrations ofLymnœa peregra(Müller) on the Shores of Loch Lomond

SynopsisSeasonal changes in the distribution ofLymnœa peregra(Müller) on a gently sloping beach of Loch Lomond have been studied in detail, with particular reference to the effects of the changes in water level which occur. At lower water temperatures the distribution can be correlated with the availability of food. At higher water temperatures the respiratory needs of adult snails cause them to remain close to the water's edge, even in the absence of food. This is not always true of young snails. Measurement of the fæces produced by such adult snails gives further evidence that a degree of starvation can occur for short periods in the summer months.Comparative data on the characteristics of the physical environment and the general distribution of gastropods in Loch Lomond are given, and the study discussed in relation to previous work on the littoral ecology of large lakes.

THE EFFECT OF GROWTH AND NUTRITION ON MITOCHONDRIA IN LIVER CELLS OF FUNDULUS HETEROCLITUS

In a recent study on Triturus pyrrhogaster (McCurdy, 1939) I found that starvation and re-feeding tend to produce definite changes in the mitochondrial picture of the liver cells. In the course of starvation, the elongated mitochondria which predominate in well-fed animals gradually give way to granular mitochondria, and these latter finally become predominant. When the procedure is reversed and starved animals are re-fed, the mitochondria change in the opposite direction, from granular to elongated. These mitochondrial changes, however, though they clearly depend upon digestive activity and degree of starvation in general, are more closely related to the amounts of fat and glycogen in the liver itself. It can be stated as a rule that in the liver cells of Triturus increase in the fat and glycogen content is accompanied by an increase in the proportion of elongated mitochondria, and decrease in the fat and glycogen content is accompanied by an increase in the proportion of granular mitochondria. There is thus an important relationship between the nutrition of cells and the form of their mitochondria. The present study is concerned with two questions: (1) Does a similar relationship between mitochondrial form and the amount of storage products exist in a different species? (2) Does growth affect the morphology of the mitochondria?

Experiments in Grass Fires againstGlossina morsitansin Southern Rhodesia

1. An account is given of two organised grass fires carried out in the Lomagundi fly-belt of Southern Rhodesia in the years 1927 and 1928, as a method of controllingG. morsitans.2. The effect of these fires on the flora and game is described, and details given of the immediate effect of these fires on both the adult fly and the puparia. The effect on the adult fly was to concentrate it along the shady watercourses and other parts of the forest where the fires were less fierce and the requisite shade was to be found.3. On the puparia, no immediate effect was noticeable. The number of dead puparia collected increased during October and November, and this is considered to be attributable to the lethal effects of the sun, not of the fire.4. The pupal period of the fly decreases from eighty-two days for puparia collected in June, to twenty-one days for puparia collected in November. The period of greatest activity of the fly, as indicated by emerging flies, density and collected puparia, is in September.5. A short account is given of the trypansome infection and food of the fly. On the average 11 per cent. of the flies are infected with pathological trypansomes in the proportion of tencongolensegroup to sevenvivaxgroup. Only one infection of the gland was found out of 1,523 dissections. There is a tendency for the percentage of infected flies to increase during the late dry season. This rise coincides with the increased visibility of the game. Examination of the fat content failed to indicate any degree of starvation amongst the flies.The food of the fly consists almost entirely of mammalian blood, only one case of avian blood being found.6. A final decision has not yet been pronounced upon the efficacy of grass fires as a means of controllingG. morsitansin Southern Rhodesia.