Kinetics of administered aggregated IgG in rats with passive Heymann's nephritis

The kinetics of radiolabeled heat-aggregated human IgG (AHIgG125I) were studied in rats with passive Heymann's nephritis (PHN) induced 72 hr previously with decomplemented rabbit antiserum to rat FX1A. Control rats were injected with decomplemented normal rabbit serum (NRS). Following administration of AHIgG125I (40 mg per 100 g of body wt) control and FX1A animals were sacrificed in groups of five each at 2, 4, 8, 16, and 24 hr and kidney, liver, spleen, lung, plasma, and blood cells obtained. 131I-Labeled human serum albumin (HSA131I) was administered prior to sacrifice as a plasma marker. In FX1A rats the following observations were made in comparison with control rats: (1) A decrease in the concentration of AHIgG125I in glomeruli was observed at 2, 4, and 8 hr after administration; (2) a significant increase in clearance reflected by a decrease in the concentration of plasma trichloroacetic acid (TCA)-precipitable radioactivity, and AHIgG125I (greater than 7 S) was present; (3) a significant increase in non-TCA-precipitable radioactivity in plasma and blood cells at most time periods; and (4) decreased concentrations of AHIgG125I in liver and spleen but not lung. The specificity of these observations was supported in separate experiments by the lack of any difference in the plasma levels of TCA-precipitable radioactivity after administration of radiolabeled albumin to FX1A and control rats. Studies in FX1A and control rats revealed no differences in body weight, kidney weight, hematocrit, blood volume, urine output, glomerular filtration rate, renal blood flow, or renal vascular resistance. A slight increase in urinary rat albumin excretion was observed in FX1A rats. The lower values of AHIgG125I observed in plasma, liver, and spleen associated with increased levels of non-TCA-precipitable radioactivity in plasma and blood cells suggest enhanced catabolism of AHIgG125I in FX1A rats, leading to decreased localization within the mesangium.     

碘[131I]-美妥昔单抗注射液的人体药代动力学研究

研究碘[131I]-美妥昔单抗注射液的人体药代动力学特征,为临床给药方案及临床应用提供依据。将按纳入标准、排除标准和剔除标准选择的患原发性肝细胞肝癌受试者24例平均分为低、中、高剂量组,各组每位受试者经插管注入相应的注射液,分别在不同时刻采集静脉血及收集尿液,测定样品的放射性计数率(min-1);采用纸层析确定各血样血清中药物的比例,依此校正各血样中药物的放射性计数率;用DASver1.0(Drug And Statistics for Windows)药代动力学程序拟合、计算血液药代动力学参数;鉴定尿液中放射性物质的组成,计算各时间段尿液放射性占注入剂量的百分率(%ID),以分析注射液在尿液的清除动力学特点。研究表明:该注射液血液药代动力学符合动力学二室模型,其在人体内分解代谢产物主要以游离131I的形式通过肾脏排泄,注入后120h内排出尿液的放射性占注入剂量的47.70%~51.16%。因此,该注射液的药代动力学特征满足临床要求,推荐临床的给药剂量为每kg人体27.75MBq注射液。     

Proteolytic activity during the absorption of [131I]γ-globulin in the new-born calf

1. Proteolytic activity within the small intestine of unsuckled calves less than 20 hr of age, anaesthetized with sodium pentobarbitone, has been assessed from the break-down of [(131)I]bovine serum gamma-globulin infused into the duodenum.2. Absorption of [(131)I]gamma-globulin was measured by analysis of venous blood, the levels of radioactivity attained in which were comparable with those when [(131)I]PVP K.60 (mean mol.wt. 160,000) was administered. When lymph collected from the thoracic duct during the absorption of [(131)I]gamma-globulin was injected into the femoral vein, the levels of radioactivity in the blood were close to those expected if the labelled material in the lymph had been retained within the plasma. These observations suggested that [(131)I]gamma-globulin was absorbed into the circulation of the anaesthetized young calf without significant break-down.3. Gel-filtration of lymph and plasma from calves fed [(131)I]gamma-globulin has confirmed that proteolysis before and during absorption was slight, since little (131)I labelled material of low mol.wt. was found.4. Gel-filtration of the contents of the alimentary tract from calves fed [(131)I]gamma-globulin showed that some hydrolysis occurred in the abomasum and duodenum and that this was reduced by barbiturate anaesthesia. Protein break-down in the terminal ileum was slight both in the conscious animal and in animals anaesthetized with sodium pentobarbitone.     

Blockade of CXCR1/2 chemokine receptors protects against brain damage in ischemic stroke in mice: Ischemia and Reparixin

OBJECTIVE:

Ischemic stroke may result from transient or permanent reductions of regional cerebral blood flow. Polymorphonuclear neutrophils have been described as the earliest inflammatory cells to arrive in ischemic tissue. CXCR1/2 receptors are involved in the recruitment of these cells. However, the contribution of these chemokine receptors during transient brain ischemia in mice remains poorly understood. In this work, we investigated the effects of reparixin, an allosteric antagonist of CXCR1/2 receptors, in a model of middle cerebral artery occlusion and reperfusion in mice.

METHODS:

C57BL/6J male mice treated with reparixin or vehicle were subjected to a middle cerebral artery occlusion procedure 1 h after the treatment. Ninety minutes after ischemia induction, the monofilament that prevented blood flow was removed. Twenty-four hours after the reperfusion procedure, behavioral changes, including motor signs, were analyzed with the SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment (SHIRPA) battery. The animals were sacrificed, and brain tissue was removed for histological and biochemical analyses. Histological sections were stained with hematoxylin and eosin, neutrophil infiltration was estimated by myeloperoxidase activity and the inflammatory cytokine IL-1β was measured by ELISA.

RESULTS:

Pre-treatment with reparixin reduced the motor deficits observed in this model of ischemia and reperfusion. Myeloperoxidase activity and IL-1β were reduced in the reparixin-treated group. Histological analysis revealed that ischemic injury was also attenuated by reparixin pre-treatment.

CONCLUSIONS:

Our results suggest that the blockade of the CXCR1/2 receptors by reparixin promotes neuroprotective effects by reducing the levels of polymorphonuclear infiltration in the brain and the tissue damage associated with middle cerebral artery occlusion and reperfusion.     

Further studies of the metabolism of thyroxine and 3,5,3′-triiodothyronine in the guinea-pig

1. Thyroxine labelled with (125)I and triiodothyronine labelled with (131)I have been administered simultaneously to guinea-pigs and their metabolism studied by whole body counting and measurement of radioactivity in urine, faeces, and blood.2. The half-life of triiodothyronine in the body is about 19 hr, significantly less than that of thyroxine (41 hr).3. After triiodothyronine administration, an unidentified iodinated compound appears in the blood which complicates the estimation of the half-life of this hormone by measurement of the radioactivity in peripheral blood.4. A previous report, based on measurements of blood radioactivity, that the half-lives of the two hormones are similar in the guinea-pig was not confirmed.     

131I-β-CIT多巴胺转运蛋白显像的基础研究

用过氧乙酸法进行 1 31 I标记 β- CIT。以 MPTP连续 5 d注入猫股静脉内 ,建立 PD模型。取正常猫 6只、PD模型猫 3只 ,每只分别注入 74 MBq/ 0 .5 ml　 1 31 I- β- CIT,观察 4 h和 2 0 h时动物体内分布情况。将 74 MBq/0 .5 ml/只 1 31 I- β- CIT经股静脉分别注入正常组及 PD组猫体内 ,于注射后 0 .5、1、2、4、2 0 h进行脑显像 ,计算纹状体 1 31 I-β- CIT的特异性结合。结果显示 :标记物 1 31 I-β- CIT放化纯达 97.6 2 %± 0 .31%。室温下放置 4 h以及分别与水、人新鲜血清孵育 4 h后 ,放化纯平均值分别为 95 .33%± 0 .5 9%、95 .14 %± 0 .87%、95 .0 6 %± 0 .6 4 %。猫静脉注射 1 31 I- β- CIT后 ,放射性主要浓聚于纹状体区 ,其次为肺、肝、肾。以每克组织中放射性占总放射性计数的百分比计算 ,正常猫 4 h和 2 0 h纹状体 /小脑比值分别为 18.31± 3.5 0和 2 0 .5 1± 2 .2 3。 2 0 h PD猫纹状体 /小脑的比值为 11.2 0± 0 .2 9,与 2 0 h正常猫相比显著下降 (P<0 .0 5 )。显像研究显示正常猫纹状体 2 0 h特异性结合为 4 .83± 0 .82 ,PD模型猫为 2 .92± 0 .6 6 ,两者有显著性差异 (P<0 .0 5 )。分布研究与显像研究的结果相符。因此 ,β- CIT是一种较理想的 DAT配体 ,碘标 β- CIT的 DAT功能显     

Intravasation of Fat from the Bone Marrow Cavity

Fat labeled with triolein-¹³¹I was introduced through a burr hole into single tibial marrow cavities and the hole was sealed. The radioactivity over the thorax was monitored for 2-5 hours. After sacrifice, the radioactivity was determined in lungs, injected tibia or leg, kidneys, brain, thyroid gland and blood. Presence of pulmonary embolic fat was verified by histologic methods. Intravasation occurred after closure of the burr hole; it was delayed in several animals and failed to occur in 1 animal. The following mean percentages of the injected activity were found: in lungs 44.8% (0.04-85.1%); in tibia 44.7% (7.1-96.8%); in other investigated tissues and organs collectively, less than 1%. In another group, the tibia was fractured either immediately after injection of the labeled fat and closure of the burr hole, or while intravasation was in progress. After 2-5 hours, the lungs contained 23.2% (0.1-65.6) of the labeled fat, which was significantly less than in animals without fracture. In 2 animals, the needle was sealed into the burr hole, and the pressure necessary to produce intravasation was measued. A pressure of 50-100 mm of H₂O produced pulmonary fat embolism as rapidly as the fat was injected.     

Specific neuro-radiological diagnosis of Herpes encephalitis in an animal model

Summary The potential of utilizing a radio-labelled derivative of the antiviral drug (E)-5-(2-iodovinyl)-2-deoxyuridine (IVDU) for the specific, non-invasive, in vivo diagnosis of Herpes simplex virus encephalitis (HSVE) was investigated in a rat model of the disease. Following pharmacological disruption of the blood brain barrier radiolabelled IVDU was administered by intra-carotid injection. Brain radioactivity was compared between control and infected animals via gamma camera scintigraphy. After clearance of non-metabolized drug, markedly higher levels of activity were found in infected brain. Post-mortem studies of cryostat sections of brain examined by autoradiography and immunochemical staining showed the radioactivity selectively accumulated in areas of virus infection. These results indicate that radio-labelled derivatives of antiviral drugs may allow the specific neuro-radiological diagnosis of HSVE.     

Blood clotting factors in cerebrospinal fluid

The activity of blood clotting factors has been investigated in cerebrospinal fluid. No cephalin-like activity was found in cerebrospinal fluid but prothrombin activity averaged about 0·5% of normal plasma activity. The activity of factor VII was negligible in almost all cases. The activity of antihaemophilic factors showed great variation but in the majority of cases it did not exceed 1% of normal plasma activity. High activity for factor V was found in almost all samples of cerebrospinal fluid.     

The break-down of [131I]γ-globulin in the digestive tract of the new-born pig

1. The intestinal absorption of [(131)I]porcine and bovine serum gamma-globulin after oral administration has been investigated in conscious pigs less than 20 hr old. Absorption was measured by the concentration of (131)I in venous blood during the 6 hr after feeding and also by the distribution of (131)I between homogenates of the alimentary tract and the rest of the animal at the end of the experiment.2. The concentration of (131)I in the blood was always low after feeding [(131)I]gamma-globulin, although a large proportion of the isotope fed was found to have left the alimentary tract. This indicated that much of the [(131)I]-gamma-globulin had been hydrolysed into fragments of low mol.wt. which were not retained in the plasma. There were no significant differences between results obtained with homologous and heterologous gamma-globulin.3. Examination by gel-filtration confirmed that, after feeding [(131)I]-serum gamma-globulin, much of the (131)I in the plasma was associated with material of mol.wt. less than 12,400 and demonstrated that the break-down of bovine gamma-globulin was comparable with that of homologous gamma-globulin.4. Comparison of the absorption of [(131)I]serum gamma-globulin from colostrum with that from a chloride solution with a similar Na(+) and K(+) concentration showed that, although the blood concentration remained low, colostrum reduced the hydrolysis of the labelled protein.5. This effect of colostrum could be simulated by the addition to the chloride solution of either the synthetic trypsin inhibitor Trasylol or a higher concentration of unlabelled protein.6. Gel-filtration of samples of the contents of the stomach, duodenum and terminal ileum after feeding [(131)I]serum gamma-globulin showed that proteolysis occurred at all these sites.     

Fractionation studies on the absorption of labelled immunoglobulin G by the gut of young rats.

1. Centrifugation in density gradients was used to study the fragments produced during intraluminal and intracellular digestion, after the injection of 125I-labelled immunoglobulin G (IgG) into different regions of the small intestine of 14 to 15-day-old (pre-closure) and 24-day-old (post-closure/ rats. 2. After injection into the proximal small intestine and into the ileum of pre-closure animals, the bulk of the radioactivity recorded for gut washes and gut homogenates was located at 4S-7S. The serum from animals which had received injections into the proximal small intestine had high radioactivity and one peak at 7S; the serum from animals which had received injections into the ileum had low radioactivity and no activity in the 7S region. 3. After injection into the proximal small intestine of post-closure animals, the bulk of the radioactivity recorded for gut wash samples was located at 3-5S--5S. Gut homogenates had peak activity at 2-5S--4S. Thus large molecular weight products can be absorbed by the proximal enterocytes of post-closure rats and degraded. The sera of these animals had low radioactivity. 4. After injection into the distal small intestine of post-closure animals, the bulk of the radioactivity recorded for gut wash and gut homogenate samples was located at 4S-7S and in this respect the radioactivity plots resembled those for (2) above. Serum radioactivity was low. 5. The effect of precipitation with trichloroacetic acid and incubation with specific antiserum upon the radioactivity of gut washes, gut homogenates and serum samples was recorded. 6. The relevance of these findings to studies on the transmission of protein by the rat small intestine is discussed.     

Milestones in the development of Lym-1 therapy

Lym-1, a monoclonal antibody (MAb) that preferentially targets malignant lymphocytes, has induced therapeutic remissions in patients with advanced non-Hodgkin's lymphoma (NHL) or chronic lymphocytic leukemia (CLL) when labeled with iodine-131 (131I). Based on the strategy of fractionating the total radiation dose, trials were designed to define the safety, toxicity, and efficacy of a series of doses of 131I-Lym-1 given 2-6 weeks apart. All patients had disease resistant to standard therapy. 131I-Lym-1 was given after unconjugated Lym-1 and the 131I dose was escalated in Phase I-II trials. Therapy proved safe. The dose-limiting toxicity was thrombocytopenia. Nonhematological toxicities did not exceed grade 2 except for infrequent instances of grade 3 hypotension. In a low-dose (LD) trial of 131I-Lym-1, tumor regression occurred in 25 (83%) of 30 patients and 17 (57 %) had durable remissions; 3 of the remissions were complete. In a maximum tolerated dose (MTD) trial of 131I-Lym-1, 10 (71%) of 14 entries that received at least two doses of 131I-Lym-1 therapy and 11 (52%) of 21 total entries had remissions; 7 of the remissions were complete. All 3 entries in the MTD cohort of 100 mCi/m2 [3.7 MBq/m2] of body surface area had durable complete remissions. Therapeutic remission and human anti-mouse antibody (HAMA) after Lym-1 therapy were associated with increased survival that was significant in multivariate analyses. Evidence for an Ab3 idiotypic network with an antibody cytotoxic for Raji human lymphoma was found in the only patient examined in detail thus far; this patient was studied because she had a high titer, HAMA and prolonged survival. In conclusion, 131I-Lym-1 induced durable remissions in patients with chemotherapy-resistant NHL or CLL and was associated with acceptable toxicity. In a subset of the patients, survival was quite prolonged perhaps related to development of Ab3.     

Multiple ST clonal complexes,with a predominance of ST131, of Escherichia coli harbouring blaCTX-M-15 in a tertiary hospital in Tanzania

The molecular epidemiology of 32 non-duplicate, CTX-M-15 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains, isolated from clinical samples, was investigated. Multilocus sequence typing revealed multiple sequence type clonal complexes: ST131 (12), ST405 (4), ST638 (3), ST38 (2), ST827 (2), ST224 (1), ST648 (1), ST46 (1) and two new sequence type clonal complexes (1845 and 1848) in 22 pulsed field gel electrophoresis clusters. The bla_CTX-M-15 gene was located on conjugative IncF plasmids. This is the first report of the worldwide emerging clonal complex ST131 linked to bla_CTX-M-15 in Tanzania and demonstrates the need for constant surveillance in developing countries to prevent the spread of these multiresistant isolates.     

Long-term changes of serum chemokine levels in vaccinated military personnel

Background

Members of the United States Armed Forces receive a series of vaccinations during their course of service. To investigate the influence of multiple vaccinations on innate immunity, we measured concentrations of a panel of immunomodulatory and pro-inflammatory cytokines in serum samples from a group of such individuals.

Results

Significantly increased levels of macrophage inflammatory protein 1α (MIP-1α), MIP-1β and interleukin 8 (IL-8) were detected. Since these cytokines are known to have anti-human immunodeficiency virus (HIV) activity, we tested the effect of serum from these individuals on HIV-1 infectivity and susceptibility of their peripheral blood mononuclear cells (PBMCs) to HIV-1 infection in vitro. Sera from vaccinated military personnel inhibited, and their PBMCs were partially resistant to, infection by HIV-1 strains tropic to CCR5 (R5), but not to CXCR4 (X4), chemokine receptor.

Conclusion

These findings demonstrate that increased anti-HIV chemokines can be detected in vaccine recipients up to 68 weeks following immunization.     

S-adenosylmethionine decreases the peak blood alcohol levels 3 h after an acute bolus of ethanol by inducing alcohol metabolizing enzymes in the liver

Introduction

An alcohol bolus causes the blood alcohol level (BAL) to peak at 1–2 h post ingestion. The ethanol elimination rate is regulated by alcohol metabolizing enzymes, primarily alcohol dehydrogenase (ADH1), acetaldehyde dehydrogenase (ALDH), and cytochrome P450 (CYP2E1). Recently, S-adenosylmethionine (SAMe) was found to reduce acute BALs 3 h after an alcohol bolus. The question, then, was: what is the mechanism involved in this reduction of BAL by feeding SAMe? To answer this question, we investigated the changes in ethanol metabolizing enzymes and the epigenetic changes that regulate the expression of these enzymes during acute binge drinking and chronic drinking.

Methods

Rats were fed a bolus of ethanol with or without SAMe, and were sacrificed at 3 h or 12 h after the bolus.

Results

RT-PCR and Western blot analyses showed that SAMe significantly induced ADH1 levels in the 3 h liver samples. However, SAMe did not affect the changes in ADH1 protein levels 12 h post bolus. Since SAMe is a methyl donor, it was postulated that the ADH1 gene expression up regulation at 3 h was due to a histone modification induced by methylation from methyl transferases. Dimethylated histone 3 lysine 4 (H3K4me2), a modification responsible for gene expression activation, was found to be significantly increased by SAMe at 3 h post bolus.

Conclusion

These results correlated with the low BAL found at 3 h post bolus, and support the concept that SAMe increased the gene expression to increase the elimination rate of ethanol in binge drinking by increasing H3K4me2.     

Distribution of a morphogenic peptide activating the head growth of hydra in rat organs following intravascular administration of3H-labeled peptide

The organ distribution of radioactivity following intravascular bolus injection of³H-Lys-head growth activator in rats was studied. Two minutes after injection the renal level of radioactivity exceeded the blood level 7-fold; 80% of the total activity was bound with the blood cell membranes. An analysis of chemical derivatives of the labeled peptide in the plasma by means of reverse-phase high-performance liquid chromatography revealed the presence of several groups of radioactive metabolites with different hydrophilic properties. High-performance liquid chromatography of blood extracts obtained from samples taken 0.5, 1, 1.5, 2, 31, and 60 min after injection showed the transformation of initially hydrophobic head growth activator into more hydrophilic fragments. The³H-Lys-head growth activator-associated radioactivity could be reliably detected in the blood onl during the first two minutes after injection. The half-period of blood-to-organ distribution of³H-labeled head growth activator lasted less than 30 seconds. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 466–469, November, 1994 Presented by E. I. Chazov, Member of the Russian Academy of Medical Sciences     

Measurement of the fall in the level of plasma radioactivity after intravenous administration of radiohippuran as a test of renal function

The level of plasma radioactivity following a single intravenous injection of ¹³¹I-labelled sodium orthoiodohippurate (radiohuppuran) falls with time in a tri-exponential fashion. The rate of fall of plasma radioactivity after an intravenous injection of radiohippuran was measured over the period 25 to 40 minutes from the time of injection and was expressed as the half-life of radiohippuran. The results suggest that this procedure may provide a valid measure of renal function which is more sensitive than the blood urea estimation but less sensitive than the creatinine clearance.     

δ-aminolevulinic acid dehydrase (porphobilinogen synthase) in two families with inherited enzyme deficiency

The inheritance of a deficient delta-aminolevulinic acid dehydrase (ALA-D; synonym: porphobilinogen synthase; EC 4.2.1.24) was studied in blood samples of two families over three generations. The propositus in each family was a young male acute hepatic porphyria patient with an almost complete ALA-D deficiency in the homozygous state (ALA-D activity less than 2% of controls). Heterozygotes are clinically non-affected (mean ALA-D 36% of controls). The mode of transmission could be traced by enzyme activity and electrophoretic polymorphism studies. Heterozygotes are detected by the demonstration of enzyme activity in the gel. The notation D was used for the gene expressing the defective enzyme. The "phenotype" D-1 was observed in six, the "phenotype" D-2 in three of all heterozygotes studied. These results are compatible with a single normal allele in heterozygotes responsible for enzyme activity. Quantitative assays and the segregation pattern in both families suggest a 3-allele-system for the inheritance of ALA-D deficiency.     

Moderate exercise training promotes adaptations in coronary blood flow and adenosine production in normotensive rats

OBJECTIVES:

Aerobic exercise training prevents cardiovascular risks. Regular exercise promotes functional and structural adaptations that are associated with several cardiovascular benefits. The aim of this study is to investigate the effects of swimming training on coronary blood flow, adenosine production and cardiac capillaries in normotensive rats.

METHODS:

Wistar rats were randomly divided into two groups: control (C) and trained (T). An exercise protocol was performed for 10 weeks and 60 min/day with a tail overload of 5% bodyweight. Coronary blood flow was quantified with a color microsphere technique, and cardiac capillaries were quantified using light microscopy. Adenine nucleotide hydrolysis was evaluated by enzymatic activity, and protein expression was evaluated by western blot. The results are presented as the means ± SEMs (p<0.05).

RESULTS:

Exercise training increased the coronary blood flow and the myocardial capillary-to-fiber ratio. Moreover, the circulating and cardiac extracellular adenine nucleotide hydrolysis was higher in the trained rats than in the sedentary rats due to the increased activity and protein expression of enzymes, such as E-NTPDase and 5′-nucleotidase.

CONCLUSIONS:

Swimming training increases coronary blood flow, number of cardiac capillaries, and adenine nucleotide hydrolysis. Increased adenosine production may be an important contributor to the enhanced coronary blood flow and angiogenesis that were observed in the exercise-trained rats; collectively, these results suggest improved myocardial perfusion.     

Autoradiographic localization of 131I-labelled thyroxine in the tissues of rat

An attempt was made to visualize the sites of localization of 131I-labelled thyroxine in the tissues of the rat by autoradiographic dipping techniques. The maximal uptake of 131I-throxine in rats occurred at 12 hours in all the tissues examined. The radioactivity continued to decrease from 12 to 36 hours after the injection. In the liver and kidney, the decline after 12 hours was rather marked. The radioactivity decreased only slightly from 12 to 36 hours in the spleen. After 3 hours of injection, the radioactivity was consistently higher in the thyroid follicular epithelial cells than in the interfollicular connective tissue. A high concentration of radioactivity was found at the periphery of the colloid areas.