The effect of CdCl2 and AgNO3 pretreatment on the distribution of 110mAg+ in rat liver

The distribution of 110mAg in the elution fractions obtained from gel filtration (Sephadex G-75) of the supernatants of rat liver homogenates was studied. 110mAgNO3 was administered i.v. at the doses 0.183 and 0.912 mg Ag+ . kg-1 . b . wt.and rats were killed 30 min after the administration. Differential centrifugation of the homogenates was performed to determine 110mAg+ distribution in subcellular structures of hepatocytes. The effect of CdCl2 and AgNO3 pretreatment (2 s.c. injections of 2.5 mg . kg-1 during 48 h) was investigated and results were compared with those obtained without pretreatment. It was found that AgNO3 pretreatment does not affect 110mAg+ distribution in the elution fractions and the major part of the metal is concentrated in the high-molecular-weight protein fraction. On contrary, after CdCl2 pretreatment almost all 110mAg+ is bound in the metallothionein (MT) fraction. Differential centrifugation revealed the main portion of the metal in nuclei and cell membranes and only small amount in lysosomal supernatant. After CdCl2 pretreatment the content of 110mAg+ in supernatant considerably increases. Results confirm the affinity of silver to MT and moreover show that this metal probably does not significantly induce the MT synthesis in the liver tissue.     

Radioautographic study on the localization of an anti-allergic agent, tranilast, in the rat liver

In order to demonstrate the localization associated with metabolism of an anti-allergic agent, Tranilast, in the liver, light microscopic radioautography of the liver was performed. Rats were administrated orally with 3H-Tranilast, and were sacrificed at 15 minutes to 24 hours after the administration. The livers were taken out and fixed, embedded and processed for light microscopic radioautography. 3H-Tranilast was absorbed rapidly, and the radioactivity in the liver increased and decreased within several hours. The number of radioautographic silver grains reached a maximum 3 hours after the administration. From 1 to 6 hours after the administration, the silver grains decreased from the portal area toward the central area. Seventy to 80% of all silver grains on the hepatocytes were retained in the cytoplasms of the hepatocytes at any experimental period. From these results, it was concluded that the localization of radioautographic silver grains was associated with Tranilast uptake of hepatocytes in each hepatic lobular compartment and that the metabolic process from uptake to excretion of Tranilast took part in the hepatocytes in each hepatic lobular compartment.     

The distribution kinetics of waterborne silver-110m in juvenile rainbow trout

Juvenile rainbow trout (Oncorhynchus mykiss) were subjected to a 2-day radioactive pulse of 110mAg at 11.9 microg/l (as AgNO3), followed by a 19-day post-tracer exposure to non-radioactive Ag(I) (3.8 microg/l). The distribution of 110mAg in the gills, liver, intestine, kidney, brain and remaining carcass was investigated over a 19-day post-tracer period. Initially, the intestine contained the highest proportion of the 110mAg burden (34%), however, by day 8, less than 5% of the total radioactivity remained in this tissue. The majority of the 110mAg eliminated from the intestine appeared to distribute to the liver. Eventually, the 110mAg content in the liver accounted for as much as 65% of the total radioactivity in the fish. Apart from the liver and intestine, only the gills and carcass contained any appreciable amount (>5%) of the total body 110mAg content. Liver and gill samples were fractionated using differential centrifugation techniques to discern the subcellular distribution of 110mAg in these tissues. In the liver, the 110mAg levels in the cytosolic fraction increased from 35% to 72% of the total cellular burden between days 8 and 19, respectively. The radioactive pulse in the gills was predominantly found in a membrane compartment termed the nuclear fraction ( approximately 60% of the total). Little change was observed over time (day 8 to day 19) to the subcellular distribution of Ag in the gills. Using size-exclusion chromatography, most ( approximately 70%) of the 110mAg content in the liver cytosol eluted at a molecular weight characteristic of metallothionein. The cytosolic distribution of 110mAg in gills was quite diffuse, occurring primarily in the heavy molecular weight fractions.     

Influence of the arachidonic acid cascade on the in vitro hepatic response to hypoxia.

Studies were undertaken to determine the effect of arachidonic acid, the precursor of bisenoic prostanoic acid derivatives, on the response of the isolated, perfused rabbit liver to hypoxia. Two and one half hours of severe hypoxia resulted in significant increases in hepatic vascular perfusion pressure, tissue wet weight, and the rates of cellular loss of lactic dehydrogenase, malic dehydrogenase, and acid phosphatase into the perfusing medium. Hypoxia also increased the rate of hepatic PGF2 alpha production by 25% after 2 1/2 hours (p less than 0.05, hypoxia vs sham). The addition of arachidonic acid (0.1 microgram/g/min for 150 minutes) to the perfusion medium of hypoxic livers significantly attenuated the changes in perfusion pressure, tissue wet weight, and loss of cellular enzymes. Arachidonic acid administration increased the rate of PGF2 alpha production by 100% (p less than 0.05, sham vs hypoxia + arachidonic acid) within 30 min after hypoxia and maintained this rate for the duration of the study. These results demonstrate that hypoxia mediated prostaglandin F2 alpha synthesis in the rabbit liver can occur in the absence of neural and blood borne components and that significant activation of the arachidonic acid cascade via the administration of exogenous arachidonic acid has a salutary effect on hepatic hemodynamics and cellular integrity during hypoxia.     

Influence of the arachidonic acid cascade on the in vitro hepatic response to hypoxia

Studies were undertaken to determine the effect of arachidonic acid, the precursor of bisenoic prostanoic acid derivatives, on the response of the isolated, perfused rabbit liver to hypoxia. Two and one half hours of severe hypoxia resulted in significant increases in hepatic vascular perfusion pressure, tissue wet weight, and the rates of cellular loss of lactic dehydrogenase, malic dehydrogenase, and acid phosphatase into the perfusing medium. Hypoxia also increased the rate of hepatic PGF_2α production by 25% after 2 hours (p<0.05, hypoxia vs sham). The addition of arachidonic acid (0.1 μg/g/min for 150 minutes) to the perfusion medium of hypoxic livers significantly attenuated the changes in perfusion pressure, tissue wet weight, and loss of cellular enzymes. Arachidonic acid administration increased the rate of PGF_2α production by 100% (p<0.05, sham vs hypoxia + arachidonic acid) within 30 min after hypoxia and maintained this rate for the duration of the study. These results demonstrate that hypoxia mediated prostaglandin F_2α synthesis in the rabbit liver can occur in the absence of neural and blood borne components and that significant activation of the arachidonic acid cascade via the administration of exogenous arachidonic acid has a salutary effect on hepatic hemodynamics and cellular integrity during hypoxia.     

~(125)Ⅰ—蜂毒肽在小鼠体内分布、吸收、排泄的研究

以氯胺T为氧化剂参照Hunter和Greenwood的多肽类化合物的碘化标记法,制备了~(125)I—标记的蜂毒肽在小鼠体内分布、吸收、排泄的研究,实验证明小鼠肌注~(125)I—蜂毒肽后,吸收很快,主要分布部位为肾、肺、心、肝、小肠、关节、脾与肌肉,脑组织中含量很少,肌肉注射后5分钟血液中含量可达70％,~(125)—I蜂毒肽主要经肾排泄,肌注后30分钟肾脏浓集最高,而尿液中以1.5小时为最高,而粪便中排泄少。     

Biliary excretion and distribution of 51Cr(III) and 51Cr(VI) in rats

The biliary excretion and distribution of 51Cr after intravenous administration of 51Cr(III) (61CrCl5) or 51Cr(VI) (Na252CrO4 . 4 H2O) was studied in rats. The cumulative biliary excretion of 51Cr reached 24 hrs after the injection was significantly higher after administration of 51Cr(VI) than after 51Cr(III) 3.51+/-0.7% and 0.51+/-0.05% of administered dose, respectively). This difference was especially due to a higher rate of biliary excretion of 51Cr in the first hours after 51Cr(VI) administration. The excretion of 51Cr via faeces was also higher after administration of 51Cr(VI) (7.35+/-0.45%) OF ADMINISTERED DOSE, AS AGAINST 4.23+/-0.23% after 51Cr(III). On the other hand, no significant difference in urinary excretion of 51Cr was found. Statistically significant differences were also observed in the distribution of 51Cr in the organism after administration of both valence states of the metal.     

Age-related differences in the effect of glucagon on metabolism in rat liver.

The authors found differences in the metabolic response of 10- and 120-day-old rats to glucagon. In 10-day-old young, the administration of glucagon was followed in 5 min by an abrupt small increase in the blood sugar level, which continued to rise and attained the maximum 2 hours after the injection of glucagon. In adult rats there was an abrupt large increase in the blood sugar level in the first minutes after administering glucagon; after that the blood sugar level fell, but remained significantly higher than in the controls. In a series of experiments on the isolated perfused liver, no differences were found in glucose and protein release from the liver into the perfusion medium, but the protein concentration in the liver of the younger rats fell. The results show that the liver of young rats, after the injection of glucagon, draws on its own protein resources for the substrates needed for gluconeogenesis.     

Biliary excretion and organ distribution of 14C radioactivity after 14C-2-ethylhexyl acrylate administration in rats

Rats were intravenously administered (14C)-2-ethylhexyl acrylate at the dose 10 mg/kg or 50 mg/kg b. w. Biliary excretion of 14C-radioactivity was followed in 1-3 hour intervals within the first 24 hours after administration. The rats were then sacrificed and distribution of 14C-radioactivity was followed in some organs. Highest radioactivity was found in liver, less in the kidneys and the least in the brain. A significant increase of bile flow was observed. In the 24-hour intervals 2.2% of the dose was eliminated via bile at both dosages, most of it (83%) during the first 3 hours.     

Effect of exogenous carnitine on carnitine homeostasis in the rat

The interaction of exogenous carnitine with whole body carnitine homeostasis was characterized in the rat. Carnitine was administered in pharmacologic doses (0-33.3 mumols/100 g body weight) by bolus, intravenous injection, and plasma, urine, liver, skeletal muscle and heart content of carnitine and acylcarnitines quantitated over a 48 h period. Pre-injection urinary carnitine excretion was circadian as excretion rates were increased 2-fold during the lights-off cycle as compared with the lights-on cycle. Following carnitine administration, there was an increase in urinary total carnitine excretion which accounted for approx. 60% of the administered carnitine at doses above 8.3 mumols/100 g body weight. Urinary acylcarnitine excretion was increased following carnitine administration in a dose-dependent fashion. During the 24 h following administration of 16.7 mumols [14C]carnitine/100 g body weight, urinary carnitine specific activity averaged only 72 +/- 4% of the injection solution specific activity. This dilution of the [14C]carnitine specific activity suggests that endogenous carnitine contributed to the increased net urinary carnitine excretion following carnitine administration. 5 min after administration of 16.7 mumol carnitine/100 g body weight approx. 80% of the injected carnitine was in the extracellular fluid compartment and 5% in the liver. Plasma, liver and soleus total carnitine contents were increased 6 h after administration of 16.7 mumols carnitine/100 g body weight. 6 h post-administration, 37% of the dose was recovered in the urine, 12% remained in the extracellular compartment, 9% was in the liver and 22% was distributed in the skeletal muscle. In liver and plasma, short chain acylcarnitine content was increased 5 min and 6 h post injection as compared with controls. Plasma, liver, skeletal muscle and heart carnitine contents were not different from control levels 48 h after carnitine administration. The results demonstrate that single, bolus administration of carnitine is effective in increasing urinary acylcarnitine elimination. While liver carnitine content is doubled for at least 6 h following carnitine administration, skeletal muscle and heart carnitine pools are only modestly perturbed following a single intravenous carnitine dose. The dilution of [14C]carnitine specific activity in the urine of treated animals suggests that tissue-blood carnitine or acylcarnitine exchange systems contribute to overall carnitine homeostasis following carnitine administration.     

Induction and degradation of Zn-, Cu- and Cd-thionein in Chang liver cells

Human liver cells (Chang liver) were exposed to 5 micrograms Zn, 2.5 micrograms Cu or 1 microgram Cd/ml in cultured medium. These exogeneous heavy metals were accumulated by the cells and induced de novo synthesis of metallothionein after a 3-h incubation period. The production of Zn-, Cu- or Cd-thionein started in the cells with accumulation of 1 nmol Zn, 0.3 nmol Cu and 0.1 nmol Cd/mg cytosol protein and subsequently the amounts of metal-binding thioneins increased in agreement with the relative amount of metal accumulated in the cytosol over a 24-h period. When cells containing Zn- or Cu-thionein were placed in metal free medium, 70% or 25% of the zinc or copper bound to each original metallothionein was released after 3 h; bound metals decreased to 85% and 65% respectively after 24 h. The disappearance of metal from metallothionein correlated with increases of metal in the medium. On the other hand, 35S-counts incorporated into Zn- and Cu-thionein decreased only to 40% and 15% of the levels in the original metallothionein after 3 h; 35S-counts decreased to 65% and 45%, respectively, after 24 h, indicating that metals bound to metallothionein decreased more quickly than 35S-counts. These results suggest that metals were released from metallothionein and were excreted into the medium. However, 35S- and 109Cd-counts in Cd-thionein changed very little, if at all, in the cells even after a 24-h incubation period. Our data strongly suggest that Zn- and Cu-thionein are degraded in the cells, but that Cd-thionein remains longer than either Zn- or Cu-thionein. When cells containing Zn-thionein were incubated in metal-free medium, Zn-thionein was digested in the cells and peptide fragments ranging about 200-400 daltons were excreted from the cells.     

Effect of testosterone loading on the kinetic of faecal testosterone excretion in mallards

Intestinal passage time of coloured fodder and testosterone turnover were examined by faecal steroid analysis in mallards in the reproductive and postrefractory period. In the latter, the discharge of coloured fodder began 36 minutes after ingestion in males, and 56 minutes in females. During reproduction the discharge began 93 minutes and 112 minutes after ingestion in males and females, respectively. Total passage time was similar in the reproductive and postrefractory period in both sexes. After intraperitoneal testosterone injection, faecal samples were collected for 8 hours and testosterone levels were measured using RIA. In the postrefractory period, 1-2 hours after testosterone loading a strong increase of faecal testosterone content developed in males, meanwhile a slighter testosterone peak appeared in females. During reproduction testosterone excretion began 1.5-2 hours after injection in both sexes but in females its increase was smaller. The duration of response to testosterone loading was 5 hours in both periods and both sexes. Intensive excretion after T loading appeared earlier in males than in females, but total passage time finished at the same time: 5 hours after loading. The character of testosterone excretion was corresponding to the passage of fodder-chimus-faeces in the reproductive and postrefractory period in both sexes.     

The short-term effect of cortisol, dexamethasone and ACTH administration on the serum levels of hexuronic acids and monosaccharides in man

The levels of serum monosaccharides (SMO) and hexuronic acids (SHA) were measured in subjects without any metabolic or endocrine disease after a short-time administration of cortisol, dexamethasone and ACTH. The effects of the three hormones were evaluated in regard to the urinary excretion of free cortisol and cortisone at basal conditions. In thirteen subjects a significant increase of SMO during cortisol treatment was registered after 24 hours. A distinct difference in the response of SMO to cortisol treatment was observed in patients with normal or increased cortisol excretion, respectively. In the subjects with high urinary free corticoids a peak of SMO occurred soon after 4 hours after cortisol administration, in the next 48 hours no tendency of return towards basal levels was observed. In the subjects with normal urinary free cortisol excretion only a slight increment was seen after 24 hours. Soon after 4 hours in eight subjects dexamethasone administration resulted in an increase of SMO without regard to the excretion of urinary free corticoids. The highest values were obtained after 28 hours of dexamethasone treatment. Ten hours after cessation of dexamethasone the levels of SMO reached the basal values. In the study in which ACTH was administered, an increment of SMO was registered only in the first four hours. In the group of subjects treated with ACTH a slight difference between subjects with normal and increased corticoid excretion was seen. The levels of SHA successively increased after the administration of all three hormones, without regard to the basal excretion of urinary free corticoids. This increase persisted also 10 hours after cessation of cortisol and dexamethasone, and 40 hours after the last dosis of ACTH, respectively. The possibility of an altered metabolism of glucose through the glucuronate pathway under conditions of glucocorticoid excess is discussed.     

Early and late effects of ischemic preconditioning on microcirculation of skeletal muscle flaps

The present study was designed to investigate the early and late effects of ischemic preconditioning on muscle flap perfusion and reperfusion-induced skeletal muscle damage. Thirty-six Sprague-Dawley rats were divided into six experimental groups of six animals each. The cremaster muscle flap model and the intravital microscopy system were used to observe microcirculatory changes associated with ischemia-reperfusion injury and ischemic preconditioning. In groups 1, 2, and 3, microcirculatory measurements were taken on the same day; however, in groups 4, 5, and 6, measurements were taken a day after surgery. Group 1 served as a control. The cremaster muscle was prepared as a tube flap, subjected to an hour of perfusion without ischemia. In group 2 (ischemic preconditioning + ischemia group), the cremaster muscle tube flap was subjected to 30 minutes of ischemia and 30 minutes of reperfusion, followed by 4 hours of total ischemia. In group 3 (ischemia alone), the flap was submitted to 4 hours of ischemia alone. In group 4 (control), the cremaster muscle flaps were dissected out, preserved in the subcutaneous tunnel, and submitted to 24 hours of perfusion only. In group 5 (ischemic preconditioning + 24 hours of perfusion + 4 hours of ischemia), the ischemic preconditioning protocol was followed by 24 hours of perfusion and 4 hours of ischemia. In group 6 (24 hours of perfusion + ischemia), the same protocol was used as in group 5 without ischemic preconditioning. Functional capillary perfusion, and the diameters of the arterioles of the first, second, and third order were significantly increased in the ischemic preconditioning group during the early period, but not after 24 hours of perfusion. No differences in the red blood cell velocities of arterioles of the first, second, or third order were found in either the early-effect or late-effect groups. The numbers of rolling, adhering, and transmigrating leukocytes, however, were significantly lower in the ischemic preconditioning group at both early and late follow-up. Ischemic preconditioning of the skeletal muscle flap has both an early and a late protective effect against reperfusion injury. Ischemic preconditioning at the early interval significantly improves muscle flow hemodynamics of the flap and attenuates leukocyte-mediated reperfusion injury. After 24 hours of reperfusion, however, ischemic preconditioning failed to improve the flow hemodynamics of the flap, yet it still protected the skeletal muscle flap from leukocyte-mediated reperfusion injury.     

兔脑微栓塞模型脑血流动力学的CT灌注动态变化

目的探讨兔脑微栓塞模型CT灌注成像（CT perfusion imaging,CTPI）脑血流动力学的动态变化规律。方法 30只新西兰兔,随机分成两组,A组：假手术对照组5只,B组：微栓塞组25只。经颈外动脉向颈内动脉注入直径约0.5 mm的SiO2颗粒10枚,分别于栓塞后30 min、3 h、6 h、12 h及24 h行CTPI,24 h处死动物取脑组织行HE染色。根据HE染色结果将模型分为缺血组和梗死组,分别观察其脑血流量（cerebral blood flow,CBF）、脑血容积（cerebral blood volume,CBV）和平均通过时间（mean transit time,MTT）的动态变化规律。结果 A组CTPI及HE染色均未见明显异常。B组3只因实验意外死亡,1只因下肢静脉穿刺失败导致CTPI失败,21只行CTPI,其中18只灌注异常,3只未见明显异常。18只灌注异常的兔中,HE染色10只脑梗死,7只脑缺血,1只未见明显异常。30 min时7只缺血兔脑不同程度低灌注,表现为CBF降低,MTT延长,CBV无显著变化,3～6 h低灌注进一步加重,CBV值略降低,12 h低灌注不同程度恢复,24 h进一步恢复。30 min时10只梗死兔脑明显低灌注,表现为CBF及CBV显著降低,MTT显著延长,3只兔低灌注分别在3 h、6 h及12 h不同程度恢复,然后下一时间又迅速降低并随着时间延长进一步加剧,其余7只兔低灌注程度随时间延长逐渐加剧或在一定水平上波动。结论脑缺血3～6 h低灌注最明显,12～24 h低灌注不同程度恢复,而脑梗死随时间延长低灌注程度不断加重或一过性恢复后再次加重。脑缺血的特征是CBF和CBV的不匹配,缺血组织CBF显著降低,CBV无显著变化,而脑梗死则表现为这两个参数的一致性下降。     

Protein,nucleic acids and cell structure in the regenerating mouse liver

Summary Prior to the onset of mitotic activity in the regenerating mouse liver, the concentrations of total protein and DNA, but not of RNA, decreased to 93 per cent of their levels in normal liver. During maximum mitosis (48–72 hours), the DNA and RNA concentrations were 110 per cent of their normal levels. The concentrations of liver nucleic acids 24 hours after a sham-operation were also about 110 per cent of normal values.Increased concentrations of insoluble protein were found at 12, 24 and 144 hours after partial hepatectomy. This may reflect an increase in the stability of the liver cell membranes during the regenerative period. Increased amounts of various cytoplasmic membranes were indicated by electronmicroscopy and may also have contributed to the increase in insoluble protein.A temporary increase in the measured solubility of the liver protein occurred during maximum mitosis. It is suggested that this was due to the association of protein with lipids during the depletion of accumulated fat from the regenerating liver.This investigation was facilitated by grants from the Royal. Physiographical Society.I wish to thank Professor I. Agrell and Docent B. Karlsson for helpful advice and criticism and Miss E. K. Persson for skilled technical assistance.     

The effect of 110mAg on ceruloplasmin oxidase activity in rats

The effect of single i.v. injection of 110mAgNO3 (0.183 mg Ag+ X kg-1 b.wt.) in rats on the ceruloplasmin oxidase activity (Cp) and copper serum concentration was studied. It was found that Cp activity in the serum decreased to 70% of the control value and simultaneously serum copper concentration decrease to 30% of the control level. In both cases the decrease was independent on the time elapsed after silver administration. Comparing these results with those reported recently in mice Cu deficit in the rat serum was approximately twice higher. This fact is considered to be an inter-species difference. The concentration of copper in the hepatic supernatant significantly decreased (to eight times from control value) after silver injection. Only less than 10% of the total amount of Ag found in whole liver was taken up to hepatic supernatant. GPC analysis of the supernatant (Sephadex G-75) revealed that no Ag-metallothionein fraction is present. On the basis of the results obtained it was concluded that the mechanism of silver inhibition of Cp oxidase activity remains still in question.     

A Clinical Study of Isoniazid Inactivation

The rate of inactivation of isoniazid (INH) in a host organism varies widely, probably because of genetic factors. A simple chemical test was used to determine INH levels in 24 tuberculous patients three and six hours after oral administration of the drug. Results are expressed in terms of half-life values of free INH in the body. Seven of the 24 patients inactivated INH rapidly (half-life average: 64 minutes); the remaining 17 metabolized INH at a slower rate (half-life average: 186 minutes). The range of individual half-life values was 30 to 305 minutes. A provisional half-life limit of 110 minutes was used to define “fast inactivators”; 110-160 minutes, “mo$\tilde{d}$erate inactivators”; and over 160 minutes, “slow inactivators”. Although INH inactivation may not be directly related to therapeutic failure, the security margin of the treatment may be diminished in those patients who inactivate INH rapidly.     

Adenosine transport in liver before and after organ preservation.

The effect of 24-h cold storage of liver on nucleoside transport was investigated. Nucleoside transport was estimated under conditions when both known types of nucleoside transport, facilitated diffusion and Na+/nucleoside cotransport, were active and when one of these transport mechanisms was inhibited. The rate of adenosine transport was not decreased after long-term cold storage of the liver. Inhibition of one of the transport systems decreased the rate of adenosine uptake before and after preservation of the liver to about the same extent. The adenosine transport rate was maintained during long-term (100 min) liver perfusion ex vivo. Slight activation of energy-dependent transport in the beginning of reperfusion and the slower recovery of this transport after the second transition from Na+-free to Na+-containing perfusion are not regarded as physiologically important because they were observed after changing the ionic content of the extracellular medium. We conclude that the nucleoside transport systems in liver are quite well preserved after 24-h cold storage of the organ.