Early Stages Of Feeding Research Articles

Effect of hexachlorobenzene on male and female rat hepatic gamma-glutamyl transpeptidase levels

The effect of 200 ppm hexachlorobenzene (HCB) in the diet on hepatic gamma glutamyl transpeptidase (GGT) levels was examined in F344 male and female rats. During early stages of feeding (4–29 weeks) some females had elevated GGT levels spread throughout the periportal regions, but all those examined at 29 weeks had a few GGT positive foci. The livers of males were not affected at this time. However, after 90 weeks of feeding, males also had elevated periportal GGT activity and a number of GGT positive foci. All females had lost the periportal activity but had developed GGT positive hepatocellular tumours. It therefore appeared that elevated non-focal GGT levels are a poor indicator for HCB toxicity, but GGT positive foci may be a more reliable indicator of carcinogenic changes.

Immunohistochemical Localization of Adenosine 3':5'-Cyclic Monophosphate in Female Ixodid Tick Amblyomma americanum (L.) Salivary Glands

Localization of adenosine 3':5'-cyclic monophosphate (cyclic AMP) in alveoli of salivary glands of female Amblyomma americanum (L.) was accomplished with an indirect immunofluorescent technique. Little cyclic AMP fluorescence was seen in Type I alveoli in glands of unfed females but considerable fluorescence was seen in Type I alveoli of glands obtained from females that had fed. The most intense cyclic AMP fluorescence was observed in complex granular cells of Type II and III alveoli in glands of unfed females and glands from females in early stages of tick feeding. In the latter stages of tick feeding an increase in fluorescence in Type III alveoli was observed in cells near the lumen, possibly adluminal interstitial or transformed granular cells.

Membrane-mediated control of hepatic beta-hydroxy-beta-methylglutaryl-coenzyme A reductase.

Previously we [Sabine & James (1976) Life Sci. 18, 1185--1192] proposed that 'the activity of hepatic beta-hydroxy-beta-methylglutaryl-coenzyme A reductase is critically regulated by the fluidity of its supporting microsomal membrane'. In the present work we examined further this concept of membrane-mediated control, with respect to the specific hypothesis that such control might function as a common mechanism both for the co-ordinated regulation of other enzymes affected by cholesterol feeding and also for the subcellular integration of the several physiological factors known to influence this enzyme's activity. Contrary to earlier expectations, this hypothesis now appears not to hold. We report here that, under those conditions of short-term cholesterol feeding that affected the reductase, a variety of other microsomal enzymes did not display membrane-function interactions, i.e. neither enzymes involved in cholesterol metabolism and also affected by cholesterol feeding (cholesterol 7 alpha-hydroxylase), nor those involved in cholesterol metabolism and not affected by cholesterol feeding (hydroxymethylglutaryl-CoA hydrolase, acyl-CoA:cholesterol acyltransferase), nor those not directly involved in cholesterol metabolism at all (glucose 6-phosphatase). Furthermore, we observed no evidence for the operation of membrane-mediated control of the reductase in other situations known to influence its activity, i.e. starvation, diurnal rhythm, the very early stages of cholesterol feeding and various manipulations in vitro.

Effect of a high glucose diet on insulin binding and insulin action in rat adipocytes. A longitudinal study.

To elucidate the mechanisms whereby changes in dietary composition affect the action of insulin on glucose metabolism, insulin binding and glucose uptake and oxidation have been studied in epididymal fat pad adipocytes from rats fed high glucose diets for 5 and 10 days. After 5 days, insulin binding was increased, the mainly to an increased number of receptors (3.4 X 10(5) vs. 2.4 X 10(5) sites per cell) in spite of increased plasma insulin levels (3.0 +/- 0.2 vs. 2.1 +/- 0.1 microgram/l; P < 0.05). The maximal response of glucose oxidation to insulin was increased (925 +/- 55 vs. 510 +/- 58 n moles/2 X 10(5) cells/2h; P < 0.01) and the dose-response curve of glucose uptake was shifted to the left. After 10 days, receptor number decreased to the control level and the effect of insulin on glucose uptake and oxidation (% basal) were similar to controls. Thus, in the early stage of high glucose feeding, insulin receptor number, and insulin sensitivity of glucose uptake, and insulin responsiveness of glucose oxidation were increased.

Repeated turn-off and turn-on of fibroin gene transcription during silk gland development of Bombyx mori

To measure the rates of fibroin mRNA synthesis in the posterior silk gland of Bombyx mori through the fourth feeding, fourth molting, and early fifth feeding stages, a saturation hybridization of 3H-RNA pulse labeled for 10 or 30 min to filter-bound fibroin DNA has been carried out. A high rate, 13 molecules/gene/min, of mRNA synthesis at 4 hr before the apolysis stage decreased precipitously to 0.44 and less than 0.084 molecule/gene/min at 4 and 7 hr after the apolysis, respectively. Such low rates, in the range of less than 0.006 to 0.084 molecule/gene/min, are observed for about 30 hr, from 7 hr after the apolysis to 5 hr after the fourth ecdysis, and are followed by a rapid elevation to 2.9 and 14 molecules/gene/min at 10 and 16 hr after the ecdysis, respectively. The rates of fibroin mRNA synthesis, if any, in the middle silk gland (fibroin nonproducer cells) are always less than 0.008 molecule/gene/min. These rates of fibroin mRNA synthesis are totally different from those of synthesis of ribosomal RNA and heterogeneous nuclear RNA of high molecular weight. From these results, we propose the possibility that fibroin gene expression is regulated at the transcriptional level through the repeated turn-off and turn-on of the gene during silk gland development.

DAB-induced changes in NMR relaxation times, water and iron content of rat tissue.

T1 relaxation values of rat liver and spleen tissue have been measured over a 6-month period whilst feeding with p-dimethyl-aminoazobenzene (DAB). Measurements of tissue water and iron content have also been made. A small rise in liver T1 value during the early stages of DAB feeding, from a control value of 296 +/- 12 ms to 318 +/- 12 ms after 3 weeks, probably reflected toxic reaction to the diet rather than preneoplastic changes. Spleen T1 value showed a considerable decrease over this same period, from a mean control value of 505 +/- 14 ms to 394 +/- 21 ms after 3 weeks on the diet. The possible origins of this change are discussed.

Localization of fetal aldolases during early stages of azo-dye hepatocarcinogenesis in rat

We have looked for the synthesis of fetal aldolases A and C during the early stages of hepatocarcinogenesis induced by 3′-methyl-4-(dimethylamino) azobenzene in the rat. Using indirect immunoperoxidase and immunofluorescence techniques we show that oval and transitional cells are the main cellular sites of fetal aldolases A and C production while hepatocytes only synthesize aldolase B. The synthesis of aldolases A and C was confirmed by electrophoresis analysis. These results indicate that different cell types are involved in fetal aldolase production during the early stages of azo-dye feeding and during regeneration after carbon tetrachloride intoxication where the synthesis of these isozymes is restricted to sinusoïdal cells.

Induction of hyporesponsiveness to particulate antigen by feeding: The sequence of immunologic response to fed antigen

The sequence of immunologic response to feeding with particulate antigen (sheep red blood cell, SRBC) was studied in inbred Dark Agouti (DA) rats. Feeding of SRBC to rats led to systemic sensitization as demonstrated by the presence of agglutinating and hemolytic antibodies to SRBC in sera. These humoral responses as well as the number of specific plaque-forming cells (PFCs) to SRBC in the spleen and mesenteric lymph nodes of these animals could be boostered by the intravenous administration of SRBC during the early stages of feeding. With prolongation of feeding both hemolytic and agglutinating antibodies in sera dropped below presensitization levels. In addition, upon parenteral challenge with SRBC the number of PFCs to SRBC and the humoral antibody responses elicited in SRBC-fed rats were found to be significantly lower than those of controls. Antigen-reactive cells, however, were not completely abolished even after 10 wk of feeding. The results demonstrate that a diminished responsiveness to particulate antigen achieved by prolonged feeding is preceded by a state of immunity and is not absolute. The mechanism underlying the phenomenon remains to be elucidated.

Structure and function of the salivary glands of the tick, Boophilus microplus canestrini (Acarina : Ixodidae)

Salivary glands of the unfed tick Boophilus microplus contain three types of acini. Pyramidal cells in the type I acini have morphological characteristics indicative of epithelia involved in the secretion of hyperosmotic fluids. Granule-secreting cells in the types II and III acini are considered to secrete the enzymes and cement components required during feeding. Cells, which were insignificant in the types II and III acini of unfed ticks, develop during the early stages of feeding and are probably eventually responsible for the secretion of the excess fluid formed from the concentration of the blood meal.

Alteration of biliary ursodeoxycholic acid in guinea pig during early stages of cholestyramine feeding

The effects of cholestyramine feeding on biliary ursodeoxycholic acid, fecal excretion of bile acids and neutral sterols on cholesterol 7α-hydroxylase and hepatic HMG-CoA reductase were examined in the guinea pig. In the bile there was a 57% decrease in the concentration of ursodeoxycholic acid while an increase was observed in the concentration of chenodeoxycholic acid. Cholestyramine feeding for ten days resulted in a decrease in plasma cholesterol levels and an increase in both hepatic HMG-CoA reductase and cholesterol 7α-hydroxylase activities. The fecal excretion of both bile acids and neutral sterols was significantly increased.

Cholesterol excretion and liver cholesterol in rats during early stages of orotic acid feeding

The early effects of orotic add on the concentration of plasma cholesterol, liver cholesterol, and fecal excretion of neutral sterols and bile acids were examined. Feeding rats 1% orotic acid for a week resulted in a decrease in plasma cholesterol and an increase in liver cholesterol. The fecal excretion of bile adds and neutral sterols was decreased significantly ( P < 0.02). This decreased the total sterol excretion ( P < 0.01). In the bile there was a decrease in the concentration of chenodeoxycholic acid while an increase was observed in the concentration of β-muricholic acid.

Genetic Dissection of Cerebellar Development: Mutations Affecting Cell Position

SYNOPSIS. The spastic mutation induces swimming coordination and equilibrium deficiencies in the Mexican axolotl ( Ambystoma mexicanum ). Behavioral ontogeny studies determined that spaslks fail to develop behavior trains of sinusoidal flexures necessary to mediate escape swimming at the time of onset of cerebellar function. Behavior analysis, after lesioning different cranial nerve roots and CNS areas in wild-type animals, confirmed the “behavioral focus” of the mutation to lie in the auricle or vestibulo-cerebellum. Single unit recordings in the cerebellar auricle and adjacent brainstem vestibular zone (area acoustico-lateralis) of mutants revealed a full complement of vestibular unit types found in wild-type. However, the gene appears to alter the physical location of vestibular units in both areas, including a ventral “translocation” of cerebellar units responding to sustained ipsilateral tilt. Correlated with this unit translocation, mutant Purkinje cells and allied afferent tracts are malpositioned ventrally, i.e. , “crowded” into an ectopic zone in the ventro-posterior cerebellum. Studies on cerebellar structure at the time of onset of spasticity (early feeding stage) confirmed the ventral malpositioning of cerebellar cells and fiber tracts seen in adults. In conjunction with these larval studies, mutant larvae injected with tritiated thymidine during early cerebellogenesis and assayed at the early feeding stage revealed a medio-ventral malpositioning of labelled cells; in wild-type, labelled cells were positioned laterally. Interestingly, the neuropathology of the reeler mutation (rev., Mariani et al. , 1977) found in the mouse is remarkably similar to that of the spastic axolotl. Both cerebella are reduced in size, misshapen, and lack fissures. Purkinje cells appear ectopically in the granular layer, white matter and deep cerebellar nuclei. Although both cerebella lack structural integrity, no individual cell type shows marked or progressive degeneration, and cellular untrastructure appears intact; thus, both genes appear to act independently of the genesis of cerebellar elements. Instead, they appear to influence morphogenetic movements by which presumptive cerebellar cells attain their proper positions during the neurogenetic sequence.

Protein composition of nuclear ribonucleoprotein particles isolated from liver of rats in the early stages of feeding of 3′-methyl-4-dimethylaminoazobenzene and from hepatoma induced by the same carcinogen

The feeding of carcinogenic 3′-methyl-4-dimethylaminoazobenzene (3′-MeDAB) in the early stages results in a change in the protein composition of the nuclear ribonucleoprotein particles of the rat liver. These particles are associated with newly synthesized RNA and it is assumed that they are involved in the processing and in the transport of this RNA. After 6 weeks of feeding of this azocarcinogen, the amount of one of the main polypeptides (apparent molecular weight 42 000) is decreased and after 10 weeks of feeding the particles are devoid of this polypeptide completely. Feeding of the non-carcinogenic p-aminoazobenzene (AB) is without any effect. The loss of this polypeptide is not characteristic for the malignant transformation. In the nuclear ribonucleoprotein particles isolated from hepatoma which has been induced by 3′-MeDAB this polypeptide is present in even higher proportion to other polypeptides than it is in particles isolated from liver cells of control animals. The 3′-MeDAB binds to the proteins of the liver nuclear ribonucleoprotein particles and interferes with the RNA processing. It is proposed that the changes in the composition of the protein moiety of the particles reflect changes in the population of liver cells leading finally to the selection of hepatoma cells which are resistant to the toxic effect of 3′-MeDAB on RNA processing.

Morphology, Physiology, Behavior, and Ecology of Perca fluviatilis L. and P. flavescens Mitchill

A review of literature on Perca fluviatilis and P. flavescens indicated one difference (in the position of the predorsal bone) sufficient to maintain their separateness as species. Otherwise they are overwhelmingly equivalent biologically. Their distributions are limited by the same effects of temperature, current speed, salinity, and dissolved oxygen. They are similar in gonadal development and age at first maturity; in the effects of water temperature and latitude on spawning time, and of environmental fertility on fecundity; in spawning behavior, fecundity, and the course of larval development. Growth capacities are similar and their expression subject to population density and temperature in the same way. Both species are adapted to a diet of small live animals, but will take whatever is available; cannibalism is characteristic, and may begin at the same early feeding stage. The two species show similarities in diurnal periodicity of feeding and in total food consumption. They also have the same pattern of development of light responses, of schooling, of activity and of daily and seasonal migrations. Within the fish community they fulfill the same role as converters of invertebrate foods into a form suitable for consumption by terminal fish predators, especially Stizostedion spp., influencing the population dynamics of their predators in similar ways. Key words: Percidae, morphology, physiology, ecology, Perca, life history, growth, reproduction, yellow perch, Eurasian perch

Development of locomotor behavior in wild type and spastic (sp/sp) axolotls, Ambystoma mexicanum.

The homozygous recessive spastic mutant found in the Mexican axolotl shows violent coiling and thrashing behavior when subjected to strong tactile or electrical stimulation. In order to establish the time of onset of the first behavioral manifestation of the spastic gene, an etiological analysis of the ontogeny of swimming behavior in mutants and wild type siblings was undertaken. The locomotor patterns shown by embryos in response to an electrical stimulus were analyzed quantitatively from the embryonic early flexure stage through the larval early feeding stage. Spastic larvae failed to show dorsal-up swimming frequencies equal to those of sibling controls from day 12 (Harrison stage 40) of development indicating a lack of equilibrium. Both spastics and their siblings showed "sinusoid swimming" and "coiling" behavior in response to an aversive stimulus through day 18 (Harrison state 46, early feeding stage) of development. From day 18, wild type siblings abruptly decreased "coiling" behavior and showed strong "escape swimming" in response to an intense stimulus. Spastics never developed "escape swimming" patterns but retained a mixture of "sinusoid swimming" and "coiling" patterns characteristic of pre-feeding stage larvae.

Acute effects of hepatocarcinogens on mouse-liver microsomal antigens

The endoplasmic reticulum membranes of mouse liver have been shown to contain antigenic components which are affected by single injections of the hepato-carcinogen o-AAT. One of these antigens decreased in concentration after carcinogen treatment and another increased. Similar changes were not induced by the non-carcinogenic p-AAT, but o-AAT incorporated in the diet did affect these antigens during the early stages ( 2 weeks) of feeding.

Glucose-6-phosphatase activity in rat liver parenchyma during azo-dye carcinogenesis.

AbstractThe glucose‐6‐phosphatase (C‐6‐Pase) activity was investigated by the Wachstein and Meisel method in preneoplastic rat liver parenchyma, as well as in normal liver and hepatomas induced by 4‐dimethylaminoazobenzene (DAB).Normal liver shows a high G‐6‐Pase activity restricted to the cytoplasm of hepatocytes. At early stages of DAB feeding, the centrolobular degenerating zones give a coarser reaction while portal areas retain a normal activity. In cirrhotic liver, the intensity of the reaction varies greatly from one nodule of regeneration to another but is relatively uniform within each nodule.Hyperbasophilic foci are found in nodules with either high or low G‐6‐Pase activity. The foci developing from highly active nodules show a loss of G‐6‐Pase activity and the tumors are negative.It appears from these studies that a) the variations in G‐6‐Pase activity observed in regenerating nodules play no role in the development of hyperbasophilic foci and hepatomas, and b) the loss of activity occurring in hyperbasophilic foci and tumors probably represents a secondary feature of the neoplastic transformation.

Histochemical study on rat liver glycogen during DAB carcinogenesis.

AbstractThe distribution of glycogen in livers of DAB‐fed rats has been examined by the PAS reaction. At early stages of DAB feeding, a loss of glycogen was observed in cells of centrolobular areas undergoing a degenerative process. Intense glycogen staining was shown, on the other hand, by the hyperplastic nodules which develop from cells of periportal areas. At later stages, the formation of hyperbasophilic foci was found to be accompanied by a loss of glycogen, and the hepatomas, which apparently arise from such foci, were PAS‐negative.It thus seems that a radical change in glycogen metabolism is associated with the neoplastic transformation. Alterations inglycogen metabolism being considered irrelevant to neoplasia per se, these results suggest that hyperbasophilic foci are the sites not only of modifications in the regulation of the cell cycle that initiate neoplastic growth but also of parallel changes responsible for secondary features of tumors.

Comparative studies on the enzyme activities in the mice liver cells of normal, regenerating and tumor developed

1) It was already reported that the tumor formation in the liver of mice fed for a long period on the low protein diet added by Luteoskyrin.In present paper some histological and enzymological studies were carried out on the mice liver.2) Any remarkable change on the alkaline phosphatase activity of liver cells was not recognized between the standard diet group mice and the mice tested.Regarding glutamic oxaloacetic transaminase activity, a little deviation was found only in the early stage of feeding.3) The cysteine desulfhydrase activity in the liver cells of mice was decreased promptly, when the protein (casein) concentration in the diet was decreased. These phenomenon seemed to be retained for all the feeding period in the liver of mice fed on low protein diet as well as the liver of mice fed on low protein diet added by Luteoskyrin.This results suggested that the decreased activity of cysteine desulfhydrase was one of the essential factors of the starting point of the abnormal metabolism in mice liver.4) The β-glucuronidase activity of the mice liver increased in the middle and later period of feeding of low protein diet added by Luteoskyrin and lastly the value of the activity got approximately the same level as that of infancy.The enzyme activity of the tumor developed mice was shown a rather high value after 180 days feeding.

Studies on the dwarf disease of mulberry tree

1. In the transmission experiments of mulberry dwarf virus by adults of lozenge-marked leafhopper, Hishimonus disciguttus Walker, the rate of transmission by the leafhoppers captured at Taimei village, Kumamoto Prefecture was 48 percent, whereas the leafhoppers from Kikuchi city in the same Prefecture induced 17 percent transmission.2. The rate of transmission by nymphs of the leafhopper was 3 percent.3. In the serial transmission by each adult of leafhoppers, it was found that the leafhoppers were able to transmit the virus more readily at the later transmission stages than at the early stages of infection feeding.