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We report a patient with fibrinogen storage disease in which there was proliferation of normal-sized peroxisomes in the hepatocytes. this phenomenon has previously been described in several acquired liver diseases. We believe that this is an adaptation response due to decreased microsomal isoenzyme activity as a result of the excess accumulation of fibrinogen in the endoplasmic reticulum.

In the rat remnant kidney hydrogen peroxide (H2O2) production is increased when compared to the normal kidney. The activities of the peroxisomal H2O2-producing oxidases, D-amino acid oxidase and acylcoenzyme A oxidase, and of the extraperoxisomal superoxide dismutase are decreased in renal homogenate. The peroxisomal L-α-hydroxyacid oxidase and L-lactate oxidase as well as the peroxisomal H2O2 scavenger catalase preserve their activity. The activity of the cytosolic scavenging system, glutathione peroxidase, is decreased by 40%. A starvation period of 48 h does not produce a measurable increase in H2O2 production in the normal nor in the remnant kidney. On visual inspection, peroxisomal morphology and distribution in the renal tubules are similar in the normal and remnant kidney tissue.

C 26:0/C 22:0 ratio can be experimentally increased in serum of normal rats by oral administration of hexacosanoic acid (C 26:0) or of thioridazine, an inhibitor of peroxisomal beta-oxidation. This causes a decreased corticosterone response as well as decreased mobilization of cholesterol esters in zona fasciculata interna cells following ACTH administration. Zona fasciculata interna cells and their nuclei are enlarged and contain more Feulgen DNA in thioridazine-fed rats. The similarity of adrenocortical response to inhibition of peroxisomal beta-oxidation and to C 26:0 administration points to raised VLCFA as the common factor which is also operative in many peroxisomal diseases accompanied by adrenocortical function defects.

Evidence is given that phenothiazines depress hepatic peroxisomal fatty acid oxidation in vivo. After oral administration to rats thioridazine and chlorpromazine inhibit peroxisomal β-oxidation, evaluated by H2O2 production, during 2 weeks. In mice, this effect could not be demonstrated. However, in both species VLCFA are increased after short and long term drug administration. Electron microscopy reveals the presence of membranous structures in liver cytoplasm or lysosomes. The inhibition by thioridazine of peroxisomal β-oxidation does not lead to hepatic peroxisome proliferation. The activities of enzymes related to fatty acid breakdown are not increased and liver peroxisomes are microscopically normal.

Aristolochic acid contamination in herbal remedies leads to interstitial fibrosis, tubular atrophy, and renal failure in humans. To study the cellular mechanisms contributing to the pathophysiology of this renal disease, we studied Wistar rats treated with aristolochic acid and measured tubular and interstitial cell proliferation, epithelial/mesenchymal cell marker expression, tubular membrane integrity, myofibroblast accumulation, oxidative stress, mitochondrial damage, tubular apoptosis, and fibrosis. Oxidative stress, a loss of cadherin concomitant with vimentin expression, basement membrane denudation with active caspase-3 expression, and mitochondrial injury within tubular cells were evident within 5 days of administration of the toxin. During the chronic phase, interstitial mesenchymal cells accumulated in areas of collagen deposits. Impaired regeneration and apoptosis of proximal tubular cells resulted in tubule atrophy with a near absence of dedifferentiated cell transmembrane migration. We suggest that resident fibroblast activation plays a critical role in the process of renal fibrosis during aristolochic acid toxicity.

1. 1. In hypoxic conditions Artemia salina L. forms 3 hemoglobins, which until now had only been characterized by their electrophoretic mobility. 2. 2. We have analysed the oxygen-binding properties of these 3 hemoglobins. 3. 3. HbI shows the lowest oxygen affinity, has an almost negligible Bohr effect and it has no physiological adaptation to temperature changes. 4. 4. HbII shows an intermediate oxygen affinity and a pronounced positive Bohr effect. 5. 5. HbIII has a very high affinity for oxygen, an almost negligible Bohr effect and a good physiological adaptation to temperature changes. 6. 6. By combining the 3 hemoglobins in different proportions Artemia salina L. must be able to withstand diverging environmental conditions.

A system was developed in which it is possible to detect in vivo changes in hepatic H2O2 production, using a combination of the catalase inhibitor, 3-amino-1,2,4-triazole and methanol. In mice, starvation significantly increases hepatic H2O2 production and plasma non-esterified fatty acid concentrations. Short-term refeeding after a 24 h starvation period brings H2O2 production and plasma non-esterified fatty acid concentration back to normal in 3h. Administration of insulin 24 h after the onset of starvation normalizes H2O2 production in less than 2h and decreases non-esterified fatty acid concentration below normal values. The suppression by insulin of H2O2 production, as well as its coherence with plasma non-esterified fatty acid concentration, indicate that increased H2O2 production in starved mice reflects peroxisomal beta-oxidation.

Publisher Summary This chapter discusses the respiratory physiology of adult Artemia sauna L. in relation to oxygen availability. At constant temperature, a zone of respiratory independence above a critical oxygen tension is found. The production of lactic acid in low environmental oxygen concentration is only important in animals acclimated to high partial oxygen pressures. In animals acclimated to low oxygen concentrations, the adaptation consists of the formation of more hemoglobin and especially of hemoglobin III. Hemoglobin III has the highest oxygen affinity and at a physiological pH, it has the lowest Bohr effect and the lowest temperature sensitivity. While lactic acid production probably constitutes a short term or stress response to hypoxic conditions, the long term adaptational mechanism consists in the formation of new hemoglobin and in a change in the proportions of each of the three types of this respiratory pigment.

It has been shown previously that, by using methanol and a catalase inhibitor, 3-amino-1, 2, 4,-triazole, changes in hepatic H2O2 production in vivo can be detected. Using this method in guinea pigs and rats we could demonstrate increased H2O2 production during metabolism in vivo of aminopyrine, especially in phenobarbital-pretreated animals. In contrast, administration of antipyrine does not lead to H2O2 production. In the guinea pigs, phenobarbital induction also stimulates the H2O2 production in vivo without administration of exogenous substrates. The rate and extent of this additional H2O2 production depend on the induction state, drug metabolism and species; the major findings are in agreement with and extend previous research in vitro on microsomes, isolated hepatocytes and perfused liver.

Publisher Summary This chapter present a study on the aerobic metabolism of Artemia spec . In the study, the aerobic metabolism of the brine shrimp Artemia spec was measured with the Warburg constant volume respirometer technique. The experiments, as a part of the study, were carried out in air saturated artificial seawater and the respiratory rate was expressed as QO 2 . The most striking phenomenon in the biology of Artemia is the diapause of the dry cysts in the gastrula stage. This is characterized by the absence of any activity and no respiration can be detected. After hydration of the cysts, the development starts again and respiration increases fast. QO 2 is about 4μ1/h mg W D at the breaking stage and still rises after hatching up to a maximum of about 20 μl/h mg W D during the molting phase between instar II and instar III. After this molting, the QO 2 decreases slowly until the characteristic adult QO 2 is reached. The respiratory rate during ontogeny of Artemia shows several peaks that could all be correlated with molting stages. The chapter also presents a study on the respiratory pigment in Artemia .

1. 1. The accessory nidamental glands of the cuttlefish, Sepia officinalis L. show an intense orange-red coloration in mature females. This colour is due to carotenoid pigments which occur in symbiotic bacteria. 2. 2. Six different pigmented strains of bacteria were isolated. 3. 3. The main pigment in five of these strains is β-carotene. 4. 4. The main pigment in the sixth strain is the keto carotenoid, adonixanthin.

Reactive oxygen intermediates play a role in chronic renal injury and glomerulosclerosis. We investigate changes in renal cortex antioxidant enzyme gene expression in the rat remnant-kidney model of chronic renal failure and compare the new data to enzyme activities published earlier. Antioxidant enzyme gene expression is evaluated by Northern blot analysis of cortex mRNA, using cDNA probes for catalase, copper/zinc-containing superoxide dismutase, and glutathione peroxidase. Catalase gene expression decreases during development of renal failure; this decrease is accompanied by decreased catalase activity during the glomerulosclerosis phase of the remnant-kidney model. Copper/zinc superoxide dismutase and glutathione peroxidase gene expression remain at a normal level during progression of the model, whereas their activities show a temporary decrease in the early remnant kidney. In the remnant-kidney model, catalase seems to be more vulnerable to reactive oxygen intermediates than superoxide dismutase and glutathione peroxidase. Our results show that antioxidant enzyme activity and gene expression do not change in the same direction at all times during disease development and that all antioxidant enzymes do not respond in the same way. Copyright 2000 S. Karger AG, Basel.