Viral RNA kinetics is associated with changes in trace elements in target organs of Coxsackie virus B3 infection

Trace elements are pivotal for the host defense, as well as potentially important for viral replication and virulence. Studies of sequential changes in viral replication in target organs of infection are sparse and a possible association with changes in specific trace elements is unknown. In this study Balb/c mice were infected with Coxsackie virus B3 (CVB3). Results indicated that sequential changes in viral replication (RT-PCR) were related to changes in trace element (arsenic, copper, iron, selenium and zinc) concentrations (as determined by ICP-MS) on days 3, 5 and 7 of the infection in serum, heart, lung, liver, pancreas, kidney, spleen, intestine and brain. After an initial viral peak on day 3, viral load drastically decreased in all organs, i.e. by >99% (serum), 97% (lung), 98% (liver), 60% (pancreas), 95% (kidney) and 93% (spleen), except in the heart, intestine and brain in which viral load increased after day 3. Selenium decreased in all organs except the heart while arsenic decreased in all organs except the kidney, spleen and brain. Moreover, selenium was negatively correlated to viral load in serum, liver, pancreas and intestine. To conclude, these findings give evidence that trace elements are directly involved in the replication of CVB3.     

Sequential changes in Fe,Cu, and Zn in target organs during early Coxsackievirus B3 infection in mice

In Coxsackievirus B3 (CB3) infection, the heart and pancreas are major target organs and, as a general host response, an associated immune activation and acute phase reaction develops. Although iron (Fe), copper (Cu), and zinc (Zn) are involved in these responses, sequential trace element changes in different target organs of infection have not been studied to date. In the present study, Fe, Cu, and Zn were measured through inductively coupled plasma mass spectrometry (ICP-MS) in the plasma, liver, spleen, heart, and pancreas during the early phase (d 1 and 3) of CB3 infection in female Balb/c mice. The severity of the infection was assessed through clinical signs of disease and histopathology of the heart and pancreas, including staining of CD4 and CD8 cells in the pancreas. During infection, the concentrations of Fe, Cu, and Zn changed in the plasma, liver, and pancreas, but not in the spleen and heart. The changes in plasma Cu, Zn, and Fe seemed to be biphasic with a decrease at d 1 that turned into increased levels by d 3. Cu showed similar biphasic changes in the liver, spleen, and pancreas, whereas, for Zn and Fe, this pattern was only evident in the liver. In the pancreas, the reverse response occurred with pronounced decreases in Fe (23%, p < 0.05) and Zn (64%, p < 0.01) at d 3. Although the pathophysiological interpretation of these findings requires further research, the sequential determination of these elements may be of clinical value in enterovirus infections in deciding the stage of disease development.     

Susceptibility of chickens to avian encephalomyelitis virus. IV. Behavior of the virus in laying hens.

Some laying hens 6 months of age were inoculated subcutaneously or orally with a chick embryo--adapted strain of avian encephalomyelitis virus and examined for propagation of the virus in the body. When inoculated subcutaneously, the virus appeared in liver, spleen, ovarian follicle, and muscle at the site of inoculation 1 day, in kidney and lumbar part of the spinal cord 3 days, in the pancreas 5 days, in heart, duodenum, and cervical part of the spinal cord 7 days, and in the brain 11 days after inoculation. After its appearance, it increased gradually in amount in liver, spleen, pancreas, muscle at the site of inoculation, and cervical and lumbar parts of the spinal cord, but remained at a low level in any other organ. When examined 14 days after inoculation and later, it was distributed mainly in the central nervous system. It was detected from 12 of 16 organs examined. The highest virus level in each organ was 10(2.6)/0.1 g in pancreas and lumbar part of the spinal cord, which were followed by muscle at the site of inoculation (10(2.0)/0.1 g), spleen (10(1.8)/0.1 g), cervical part of the spinal cord, heart, and liver in the order listed. When inoculated orally, the virus was found sporadically in spleen, pancreas, kidney, cecum, ovarian follicle, and lumbar part of the spinal cord. The virus level was low in these organs, of which pancreas, kidney, and lumbar part of the spinal cord showed the highest virus level, or 10(1.3)/0.1 g.     

Levels and distribution of zinc,copper, magnesium,and calcium in rats fed different levels of dietary zinc

Effects of altered dietary zinc on levels of zinc, copper, magnesium, and calcium in organ and peripheral tissues were studied. When rats fed a zinc-deficient diet (1.3 μg Zn/g) for 28 d were compared with rats fed a control diet (37.5 μg Zn/g), levels of zinc were slightly lower in plasma, hair, and skin and 50% lower in femur and pancreas, whereas the levels of copper were higher in all tissue except plasma. Magnesium levels were higher than controls in the heart and lower in the spleen, whereas the calcium levels were lower in plasma, lung, spleen, kidney, and skin and strikingly higher in brain, hair, and femur. When rats fed a zinc-supplemented diet (1.0 mg Zn/g) were compared to the same conrols, levels of zinc in these were higher in all organs and peripheral tissues studied, except heart, lung, and liver; copper levels were higher in liver, kidney, and spleen; magnesium levels were significantly higher in the spleen, but were little affected in other tissues, although calcium levels were higher in pancreas, spleen, kidney, and skin and lower in plasma and hair. These data indicate that overall copper organ and peripheral tissue levels are affected inversely, and zinc and calcium levels directly, by zinc nutriture.     

Tissue Response to a Supplement High in Aluminum and Silicon

The objective was to determine the effects of sodium zeolite A (SZA) on mineral metabolism and tissue mineral composition in calves. Twenty calves were placed on study at 3 days of age and were placed into one of two groups: SS, which received 0.05% BW SZA added to their milk replacer, and CO, which received only milk replacer. Blood samples were taken on days 0, 30, and 60 for mineral analysis. Urine and feces were collected on day 30 for mineral metabolism, and on day 60, the calves were euthanized, and samples were taken from numerous organs for mineral analyses. Aluminum retention was increased in the SS calves (p = 0.001). Silicon concentrations were increased in the aorta, spleen, lung, muscle, and kidney of the SS calves, and aluminum was increased in all SS tissues (p < 0.05). Calcium concentrations were increased in aorta, liver, muscle, and tendon; phosphorus concentrations were increased in aorta, but decreased in plasma; magnesium concentrations were increased in aorta, heart, kidney, liver, and pancreas, but decreased in plasma; and iron concentrations were decreased in kidney and liver (p < 0.05). The accumulation of tissue aluminum and therefore potential adverse consequences may preclude any benefits of using SZA as a dietary supplement.     

Survey of fructose 1,6-bisphosphatase isoenzyme in rat organs and ontogenic expression of the enzyme in rat fetus

1. Among eleven tissues of rat, the liver type of fructose 1,6-bisphosphatase (FBPase) subunit was detected in the liver, kidney, testis, pancreas and lung by Western blot analysis using anti-(liver FBPase) or anti-(muscle FBPase) serum. 2. The muscle type of the enzyme subunit was detected only in the pancreas other than skeletal muscle. Both types of the enzyme subunit were found in the pancreas. 3. Neither anti-(liver FBPase) nor anti-(muscle FBPase) serum detected the band of enzyme subunit on the blots of the extracts of brain, heart, small intestinal mucosa, spleen and placenta. 4. FBPase is present in fetal rat liver at least as early as the 14th day of gestation. 5. In agreement with the increase in immunological staining density, the level of the enzyme activity in fetal liver increased exponentially during fetal development. 6. The muscle enzyme was not detected until the fetus reached the 19th day of gestation.     

Quantitative investigation of antigen and immune response in nervous and lymphoid tissues of Atlantic halibut (Hippoglossus hippoglossus) challenged with nodavirus

The present study reports the quantitative analysis of the spatio-temporal development of nodavirus infection and corresponding immune response in juvenile Atlantic halibut (Hippoglossus hippoglossus) challenged by intramuscular injection of nodavirus. Novel quantitative real-time RT-PCR protocols were applied to evaluate the absolute copy numbers of nodavirus RNA2 (RNA2) and secretory-IgM mRNA (sec-igmicro) in the eye, brain, mid/posterior kidney and spleen sampled over a period of 81 days. In the eye and brain, levels of both RNA2 and sec-igmicro increased significantly early in the infection. In the spleen and mid/posterior kidney, both RNA2 and sec-igmicro were detected but the levels remained unchanged during the experimental period. The levels of RNA2 and sec-igmicro in the eye and brain were strongly correlated (P<0.0001). Nodavirus antigen was demonstrated by immunohistochemistry (IHC) in the retina of eyes from a relatively few fish from day 34 post challenge (brain not examined), but not at any time in the spleen and anterior kidney. By IHC, IgM+ cells were observed in conjunction with nodavirus positive IHC labelling in the retina. In both the spleen and anterior kidney, the number of IgM+ cells increased from day 3 post challenge. By conventional real-time RT-PCR, RNA2 was only sporadically demonstrated in the posterior intestine, heart and gills. ELISA analysis revealed a nodavirus specific antibody response in serum that was significant from day 18 post challenge. No clinical signs or mortality related to nodavirus infection were observed in the challenged halibut. The results suggest that the nodavirus infection induced a significant antibody response through activation of B-cells in the kidney and spleen, and involved a substantial migration of antibody-secreting cells to infected peripheral tissues.     

Multi-element analysis of trace element levels in human autopsy tissues by using inductively coupled atomic emission spectrometry technique (ICP-AES).

Autopsy tissue samples from the brain front lobe, cerebellum, heart, kidney (cortex and medulla), liver, pancreas, spleen and ovary were analysed for AL, B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr and Zn in 30 (17 women and 13 men) subjects ranging in age from 17 to 96 years at Haukeland University Hospital in Norway. The tissues were selected from macroscopically normal organs and samples were handled according to guidelines recommended to avoid contamination in the pre-analytical phase. Concentration of the trace elements were determined by the inductively coupled plasma atomic emission spectrometry technique (ICP-AES). In most tissues the concentrations of the essential trace elements followed the order Fe> Zn> Cu> Mn> Se> Cr> Co except in the ovary where Se was higher than Mn. The liver was the major site of deposition for Co, Cu and Mn as well as the spleen for Co, brain front lobe for Cu and pancreas for Mn. Ba, Sr and Ni built up in the ovary foLLowed by the kidney. Older subjects accumulated Ba and Sr in most tissues, whereas Al accumulated in the kidney cortex and Cd in the brain cerebellum. Generally males had higher concentrations of trace elements in the different tissue sampLes than females with the exception of Mn in the brain front lobe and heart and Sr in the liver. ICP-AES is a useful method to assess the concentration and the profiLe of trace elements in human autopsy tissues.     

Model to evaluate the toxic effect of drugs: vincristine effect in the mass of organs and in the distribution of radiopharmaceuticals in mice

There are evidences that the biodistribution of radiopharmaceuticals can be modified by some drugs. As chemotherapeutic drugs present important toxic effects, we studied the vincristine effect in the mass of organs and are trying to develop a model to evaluate the action of chemotherapeutic drug using the biodistribution of radiopharmaceuticals. Vincristine was administered (n=15) into female Balb/c mice, the organs isolated and their mass determined. To study the vincristine effect in the biodistribution of technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) or technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA), vincristine (0.03 mg) was administered in the animals (n=15) in three doses. 99mTc-DMSA or 99mTc-DTPA was injected 1h after the last dose. After 0.5h, the animals were sacrificed and the percentage of radioactivity (%ATI) and the percentage of radioactivity per gram of tissue (%ATI/g) in each organ were calculated. The results have shown that the mass decreased significantly (Wilcoxon test, P<0.05) in thymus, spleen, ovary, uterus, kidneys, pancreas. The %ATI to 99mTc-DMSA increased in lung, pancreas, heart, thyroid, brain, and bone, and the %ATI/g increased in uterus, ovary, spleen, thymus, kidney, lung, liver, pancreas, heart, thyroid, brain and bone. To 99mTc-DTPA, the %ATI increased in uterus, ovary, spleen, thymus, kidney, lung, liver, stomach, heart and bone, and the %ATI/g increased in uterus, ovary, spleen, thymus, kidney, lung, liver, stomach, heart and bone. The results were statistically significant (Wilcoxon test). The results can be explained by the metabolization, therapeutic, toxicological or immunosupressive action of the vincristine. This model, probably, should be used to evaluate the toxic effect of various drugs.     

Organ distribution of rat kynureninase and changes of its activity during development

Kynureninase activity was measured in various organs of the rat by a sensitive assay method based on the use of an HPLC system. High activities were detected in liver, kidney and spleen, and much lower activities in adrenals, intestine, lung, heart, brain, skeletal muscle and pancreas. Kynureninase of liver, kidney and spleen showed the same molecular weight (110,000) and the same isoelectric point (pI 5.4). They also showed the same properties of heat stability and apparent optimum pH. The enzymes in kidney and spleen were localized in the cytosol. The developmental study showed increasing activities of the enzyme after birth and a maximum on the 60th day in both liver and spleen. The activity in kidney increased after birth and reached a plateau on the 30th day.     

Plasma dependent and independent accumulation of betaine in male and female rat tissues

Tissue betaine is an intracellular osmolyte that also provides a store of labile methyl groups. Despite these important biological roles, there are few data regarding tissue betaine content. We measured the betaine concentration of plasma and various tissues (brain, heart, lungs, liver, kidney, spleen, intestine, reproductive tissues, skeletal muscle and skin) in male and female rats and assessed whether there were any gender-specific differences in betaine content or distribution and whether there was any relationship between tissue accumulation and plasma levels. Betaine was highest in the liver and kidney with values ranging from 1.6 to 9.5 mmol/l and 2.0 to 5.4 mmol/l, respectively. Plasma betaine concentrations were significantly lower than tissue levels except in the brain (? 25 % of plasma) and skeletal muscle (similar to plasma). Regression analysis of the combined male and female data revealed a significant plasma-related accumulation of betaine in the heart, skin and skeletal muscle, while the lung, liver, kidney, spleen, and intestine showed significant plasma-related and plasma-independent accumulations of betaine. The betaine content of the skin, liver and kidney was not significantly different between males and females, but in plasma and all tissues analyzed it was significantly higher in males (P<0.01).     

Distribution of amiodarone and its metabolite, desethylamiodarone, in human tissues

The distribution of the antiarrhythmic drug amiodarone and its principal lipophilic metabolite, desethylamiodarone, was determined in postmortem tissues of six patients who received amiodarone therapy (treatment period, 6-189 days; total dose, 4.8-127.0 g). Amiodarone concentration was highest in liver, lung, adipose tissue, and pancreas, followed by kidney, heart (left ventricle), and thyroid gland, and lowest in antemortem plasma. There was no measurable amiodarone in brain (less than 1.0 microgram/g). Desethylamiodarone concentration was highest in liver and lung, followed by pancreas, adipose tissue, kidney, heart, thyroid gland, and brain, and lowest in plasma. For most patients, the desethylamiodarone concentration was higher than the amiodarone concentration in liver, lung, kidney, heart, thyroid gland, and brain, whereas the parent drug concentration was higher than the metabolite concentration in adipose tissue, pancreas, and plasma. Tissue amiodarone and desethylamiodarone concentrations appeared to be related more closely to the total dose of amiodarone than to their respective plasma concentrations. One patient died of apparent amiodarone-induced pulmonary toxicity after an 18-day period of pharmacotherapy. Clinical evidence of pulmonary dysfunction appeared at 15 days after the initiation of amiodarone therapy, and the patient died at 23 days. Histologic assessment of a lung necropsy specimen revealed acute alveolar interstitial damage. This case represents the earliest reported incident of amiodarone-induced pulmonary toxicity.     

Tissue distribution of glycosphingolipids in a case of Fabry's disease

A survey was made of the glycolipid composition of various tissues, including liver, spleen, kidney (cortex and medulla), lymph node, pancreas, prostate gland, heart muscle, thenar muscle, gastrointestinal smooth muscle, frontal cerebral cortex, anterior thalamus, brain stem, a peripheral autonomic ganglion, and renal arterial intima and media, from a patient who died with Fabry's disease. The tissues had been fixed in formalin for 3 yr. Analytical data on trihexosyl ceramide from heart muscle and pancreas indicate a structure identical to trihexosyl ceramide from kidney: galactosylgalactosylglucosyl ceramide. Fatty acid compositions of trihexosyl ceramide and dihexosyl ceramide revealed a wide range of fatty acids, with 16:0, 18:0, 20:0, 22:0, 24:0, and 24:1 predominating. These glycolipids comprised 10-41% of the total lipid in the formalin-fixed organs studied. Trihexosyl ceramide predominated in all tissues and was the only glycolipid found in muscle tissues, lymph node, and arterial tissues. Dihexosyl ceramide was found in kidney, pancreas, liver, spleen, and cerebral tissues. The accumulation of trihexosyl ceramide in cardiac muscle and arterial tissues may account in part for the cardiovascular complications so prominent in Fabry's disease.     

Susceptibility of chickens to avian encephalomyelitis virus. II. Behavior of the virus in day-old chicks.

The VR strain of avian encephalomyelitis virus, which had been adapted to embryonated hen's eggs, was inoculated into 2-day-old chicks by the subcutaneous route (10(2.5) approximately 10(3.0) EID50) or by the oral route (10(4.8) EID50). The chicks were examined chronologically for the distribution of the virus in the body. As a result, minute amounts of the virus were detected from the liver, spleen, pancreas, and muscle at the site of inoculation one day after inoculation and various amounts from almost all the organs 3 days and more after inoculation. The virus titer could nearly reach a maximum 7 to 9 days after inoculation. Above all, such high virus titers as ranging from 10(4.3) to 10(5.8) EID50/0.1 g were demonstrated in the brain, heart, liver, spleen, and pancreas. After that, there was a tendency for virus titer to decrease in most organs and for virus to multiply persistently in the pancreas, brain, and eyeball. Virus titer was maintained at a level of 10(2.3) approximately 10(2.8) EID50/0.1 g in these three organs even 21 days after inoculation. In the group of subcutaneous inoculation, all the chicks manifested clinical signs of infection 5 to 10 days after inoculation. On the other hand, no chicks were involved in clinical infection in the group of oral inoculation. Multiplication of the virus was delayed in the body of these chicks. Small amounts of the virus were detected from the spleen and pancreas 11 days after inoculation. Low titers (10(2.7) EID50/0.1 g at the highest) of the virus were only detected from the brain, spinal cord, spleen, pancreas, esophagus, and other organs 14 and 21 days after inoculation.     

Protein tyrosine phosphorylation in normal rat tissues

• 1.1. Exogenous and endogenous tyrosine protein phosphorylation activities were examined in soluble and partieulate fractions from various normal tissues by using poly-[Glu-⁸⁰Na, Tyr²⁰] and a monoclonal antibody specific for phosphotyrosine.
• 2.2. Phosphorylation of the exogenous substrate by the partieulate forms of TPKs was 2- to 10-fold higher than by soluble forms. The activities of partieulate and soluble enzymes decreased in the following order: spleen > (thymus = kidney) > testes ⩾ (pancreas = liver = brain) > heart.
• 3.3. The level of endogenous phosphorylation in the tissues decreased respectively in the following order: thymus > brain ⩾ (pancreas = liver) > spleen > testes > kidney > heart for the partieulate fractions, and spleen > thymus > brain > pancreas ⩾ liver > testes > kidney > heart for the soluble fractions.
• 4.4. A large number of phosphotyrosine-containing proteins were detected. In addition, several phosphotyrosine-containing proteins of similar molecular weight were found in different tissues and fractions.

     

Effect of age and dietary protein level on tissue mineral levels in female rats

Mineral (phosphorus, sulfur, potassium, calcium, magnesium, iron, zinc, copper, and manganese) concentrations were measured in plasma, and several tissues from female Wistar rats (young: 3-wk-old; mature: 6-mo-old) were fed on a dietary regimen designed to study the combined or singular effects of age and dietary protein on mineral status. Three diets, respectively, contained 5, 15, and 20% of bovine milk casein. Nephrocalcinosis chemically diagnosed by increased calcium and phosphorus in kidney was prevented in rats fed a 5% protein diet. Renal calcium and phosphorus were more accumulated in young rats than mature rats. A 5% protein diet decreased hemoglobin and blood iron. The hepatic and splenic iron was increased by a 5% protein diet in mature rats but was not altered in young rats. Mature rats had higher iron in brain, lung, heart, liver, spleen, kidney, muscle, and tibia than young rats. A 5% protein diet decreased zinc in plasma and liver. Zinc in tibia was increased with dietary protein level in young rats but was not changed in mature rats. A 5% protein diet decreased copper concentration in plasma of young rats but not in mature rats. Mature rats had higher copper in plasma, blood, brain, lung, heart, liver, spleen, and kidney than young rats. With age, manganese concentration was increased in brain but decreased in lung, heart, liver, kidney, and muscle. These results suggest that the response to dietary protein regarding mineral status varies with age.     

Tissue Distribution and Immunocytochemical Localization of Neurotrophin-3 in the Brain and Peripheral Tissues of Rats

Abstract: The tissue distribution of neurotrophin-3 (NT-3) was investigated in rats at 1 month of age using a newly established, sensitive two-site enzyme immunoassay system for NT-3, as well as the immunocytochemical localization of this protein. The immunoassay for NT-3 enabled us to quantify NT-3 at levels > 3 pg per assay. In the rat brain, NT-3 was detectable only in the olfactory bulb (0.54 ng/g wet weight), cerebellum (0.71 ng/g), septum (0.91 ng/g), and hippocampus (6.3 ng/g). By contrast, NT-3 was widely distributed in peripheral tissues. Appreciable levels of NT-3 were also found in the thymus (31 ng/g), heart (38 ng/g), diaphragm (21 ng/g), liver (45 ng/g), pancreas (892 ng/g), spleen (133 ng/g), kidney (40 ng/g), and adrenal gland (46 ng/g). An antibody specific for NT-3 bound to pyramidal cells in the CA2-CA4 regions of the hippocampus, to A cells in the islets of Langerhans in the pancreas, to unidentified cells in the red pulp of the spleen, to liver cells, and to muscle fibers in the diaphragm from rats at 1 month of age. Molecular masses of NT-3-immunoreactive proteins in the hippocampus and pancreas were 14 and 12 kDa, respectively. Thus, in rats, NT-3 was detected in restricted regions of the brain and in the visceral targets of the nodose ganglia at high concentrations. Our present results suggest that NT-3 not only functions as a classical target-derived neurotrophic factor but also can play other roles.     

Effects of nicotine and vitamin E on carbonic anhydrase activity in some rat tissues in vivo and in vitro

Effects of nicotine, nicotine + vitamin E and nicotine + Hippophea rhamnoides L. extract (HRe-1) on muscle, heart, lungs, testicle, kidney, stomach, brain and liver carbonic anhydrase (CA; EC 4.2.1.1.) enzyme activities were investigated in vivo. Groups of rats were given nicotine (0.5 mg/kg/day, i.p.), nicotine + vitamin E (75 mg/kg/day, i.g.), nicotine + HRe-1 (250 mg/kg/day, i.g.) and a control group vehicle only. The results showed that nicotine inhibited the heart, lung, stomach and liver CA enzyme activities by approximately 80% (p < 0.001), approximately 94% (p < 0.001), approximately 47% (p < 0.001) and approximately 81% (p < 0.001) respectively, and activated muscle and kidney, but had no effects on the testicle and brain CA activities. Nicotine + vitamin E inhibited the heart and liver CA enzyme activities by approximately 50% (p < 0.001), and approximately 50% (p < 0.001), respectively, and nicotine + vitamin E activated the muscle CA activity. However, nicotine + vitamin E had no effect on lung, testicle, kidney, stomach and brain CA activities. Nicotine + HRe-1 inhibited the heart and stomach CA enzyme activities by approximately 51% (p < 0.001), and approximately 32% (p < 0.002), respectively, and activated the muscle and brain CA activities, but had no effects on the lung, testicle, kidney, and liver CA activities. In vitro CA inhibition results for similar experiments correlated well with the in vivo experimental results in lungs, testicles, kidney, stomach, brain and liver tissues.     

Distribution of high mobility group proteins in different tissues of rats during aging

The distribution of high mobility group (HMG) proteins has been studied in the liver, brain, kidney, lung, spleen, testis, thymus, and heart of young (19 weeks) and old (118 weeks) rats. These proteins were extracted with perchloric acid, fractionated by CM-Sephadex column chromatography, and analysed by acetic acid-urea polyacrylamide slab gel electrophoresis. As compared with that in young rats, the level of total HMG proteins in the old increased in liver and lung, decreased in thymus, heart, brain, and kidney, and remained unchanged in spleen and testis. In particular, the levels of HMG 1 and 2 were maximum in the thymus of young rats and dropped drastically in the old. However, the amount of HMG 17 was high in the spleen of both young and old rats, though it was comparatively higher in the former. Such age-dependent variation in the level of HMG proteins of different tissues denotes indirectly differences in the functional state of chromatin, and in growth and activity of cells, during aging.     

Glutathione reductase activity and flavin concentration in guinea-pig tissues.

Glutathione reductase (GR) activity and flavin concentration were studied in systemic tissues (brain, heart, lung, liver, spleen, stomach, pancreas, muscle, kidney, testis) and blood components (erythrocytes and plasma) from male guinea-pigs. GR activity and the flavin concentration were high in kidney and liver, and low in muscle. GR activity in erythrocytes was found in a range of tissues, but flavin concentration in erythrocytes was lower than in any tissues. GR was saturated with flavin adenine dinucleotide (FAD) in almost all tissues, but not in muscle or erythrocytes.