Repetitive Intravenous Injections Research Articles

MiR155-5p in adventitial fibroblasts-derived extracellular vesicles inhibits vascular smooth muscle cell proliferation via suppressing angiotensin-converting enzyme expression

ABSTRACT Proliferation of vascular smooth muscle cells (VSMCs) plays crucial roles in vascular remodelling and stiffening in hypertension. Vascular adventitial fibroblasts are a key regulator of vascular wall function and structure. This study is designed to investigate the roles of adventitial fibroblasts-derived extracellular vesicles (EVs) in VSMC proliferation and vascular remodelling in normotensive Wistar-Kyoto rat (WKY) and spontaneously hypertensive rat (SHR), an animal model of human essential hypertension. EVs were isolated from aortic adventitial fibroblasts of WKY (WKY-EVs) and SHR (SHR-EVs). Compared with WKY-EVs, miR155-5p content was reduced, while angiotensin-converting enzyme (ACE) content was increased in SHR-EVs. WKY-EVs inhibited VSMC proliferation of SHR, which was prevented by miR155-5p inhibitor. SHR-EVs promoted VSMC proliferation of both strains, which was enhanced by miR155-5p inhibitor, but abolished by captopril or losartan. Dual luciferase reporter assay showed that ACE was a target gene of miR155-5p. MiR155-5p mimic or overexpression inhibited VSMC proliferation and ACE upregulation of SHR. WKY-EVs reduced ACE mRNA and protein expressions while SHR-EVs only increased ACE protein level in VSMCs of both strains. However, the SHR-EVs-derived from the ACE knockdown-treated adventitial fibroblasts lost the roles in promoting VSMC proliferation and ACE upregulation. Systemic miR155-5p overexpression reduced vascular ACE, angiotensin II and proliferating cell nuclear antigen levels, and attenuated hypertension and vascular remodelling in SHR. Repetitive intravenous injection of SHR-EVs increased blood pressure and vascular ACE contents, and promoted vascular remodelling in both strains, while WKY-EVs reduced vascular ACE contents and attenuated hypertension and vascular remodelling in SHR. We concluded that WKY-EVs-mediated miR155-5p transfer attenuates VSMC proliferation and vascular remodelling in SHR via suppressing ACE expression, while SHR-EVs-mediated ACE transfer promotes VSMC proliferation and vascular remodelling.

The toxicological effect of 4-week repeated intravenous injection of activin a/BMP-2 chimera and 2-week recovery study in Beagle dog*

The purposes of this study was to determine the toxicological effect of repeated intravenous administration of Activin A/BMP-2 chimera (AB204) in beagle dogs for a long period of four weeks and evaluate two-week recovery. AB204 was administered at doses of 0.08, 0.16, or 0.32 mg/kg/day to three male and three female beagle dogs for 4 weeks as the experimental group. For the control group, sterile saline was administered to three male and three female beagle dogs. For the two-week recovery test, two male and two female beagle dogs were randomly selected from the control group and the 0.32 mg/kg/day administered experimental group. General symptoms, body weight, food consumption, ophthalmological examination, electrocardiogram, urinalysis, hematology and blood biochemistry, organ weights, autopsy, and histopathological examination were observed or conducted. No animals died. There was no significant difference in any parameter evaluated between the experimental group and the control group. Histopathological examination revealed compound inflammation at the administration site in both the experimental group and the control group. The inflammation disappeared during the two-week recovery. These results indicated that repetitive intravenous injection of AB204 in beagle dog for a long period of four weeks did not show any toxicity. Therefore, no observed adverse effects level (NOAEL) of AB204 was 0.32 mg/kg/day in big animal model.

119 Visualization of Vascular Structures of the Brain Through a Novel Multispectral Fluorescence Microscope After Intravenous Application of ICG

Abstract INTRODUCTION Vascular structures are intraoperatively visualized through the eye-piece of a surgical microscope. The blood flow within the blood vessels can be demonstrated via indocyanine green (ICG) fluorescence. In this study we wanted to find out whether the development of a novel fluorescent surgical microscope, overlapping a multispectral fluorescent image on a white light image, is superior, equal or inferior, compared to the previous models. Moreover, it shall be proved, whether multispectral fluorescence enhances surgeon's orientation through the precise and clearer visualization of blood vessels and the blood flow. METHODS A total of 8 porcine animal models were used. After fixation of the animal's head the parietal cortex and the cortical blood vessels were exposed. A digital imaging of the arterial perfusion, capillary transition and venous drainage after intravenous injection of ICG (5 ml; 5 mg/ml) was then performed. The blood flow was artificially blocked by a surgical clip. After repetitive intravenous injection of ICG and visualisation with multispectral view, the surgical clip was removed and the reperfusion of the brain tissue was visualized with the real time ICG perfusion. RESULTS >The visualization of the anatomical structures of the surgical field under white light as well as the image overlapping were easily performed. The occlusion of blood vessels with surgical clips demonstrate a blockage of the ICG perfusion on the multispectral fluorescent image. The ICG perfusion was again demonstrated after removing the surgical clip and reperfusion of the blood vessel. CONCLUSION Multispectral fluorescence was shown to be superior to the classic ICG fluorescence. With the development of a novel multispectral surgical microscope, which overlaps a fluorescent image on a white light image, the data delivered to the surgeon are enhanced, compared to the previous models. Moreover, the surgeons's orientation is improved thanks to the clear visualization of blood vessels and the blood flow.

The Cardiovascular Effect of Single Injection and Toxicologic Effects of Repetitive 2-Week Intravenous Administration of Activin A/BMP-2 Chimera in Beagle Dog.

This study was performed for the purpose to evaluate the effect of activin A/BMP-2 chimera (AB204) on cardiovascular system and toxicological effect in beagle dogs. When administered AB204 at the dose of 0.32mg/kg via intravenous injection in beagle dogs, there were no changes in systolic, diastolic and mean blood pressure as well as in pulse rate, in addition that there were no differences in ORS complex, PR interval, R-R interval, QT interval and QTcV interval on the electrocardiography. Also, when administered AB204 at the doses of 0.25 and 0.5mg/kg/day via repetitive intravenous injection for 2weeks, it did not cause any significant changes in general symptoms, weight, food intake, ophthalmologic abnormality, urine, hematology, serum biochemistry, organ weight and autopsy values. Therefore, AB204 did not affect cardiovascular functions including blood pressure, pulse rate and ECG, when administered at the dose of ≤0.32mg/kg via single intravenous injection in male beagle dogs. When it was administered at the dose of 0.5mg/kg repetitive intravenous injection for 2weeks, it did not show any toxicity.

Corticotropin-releasing hormone induces depression-like changes of sleep electroencephalogram in healthy women

We reported previously that repetitive intravenous injections of corticotropin-releasing hormone (CRH) around sleep onset prompt depression-like changes in certain sleep and endocrine activity parameters (e.g. decrease of slow-wave sleep during the second half of the night, blunted growth hormone peak, elevated cortisol concentration during the first half of the night). Furthermore a sexual dimorphism of the sleep-endocrine effects of the hormones growth hormone-releasing hormone and ghrelin was observed. In the present placebo-controlled study we investigated the effect of pulsatile administration of 4×50μg CRH on sleep electroencephalogram (EEG) and nocturnal cortisol and GH concentration in young healthy women. After CRH compared to placebo, intermittent wakefulness increased during the total night and the sleep efficiency index decreased. During the first third of the night, REM sleep and stage 2 sleep increased and sleep stage 3 decreased. Cortisol concentration was elevated throughout the night and during the first and second third of the night. GH secretion remained unchanged. Our data suggest that after CRH some sleep and endocrine activity parameters show also depression-like changes in healthy women. These changes are more distinct in women than in men.

Interleukin-1β overproduction is a common cause for neuropathic pain, memory deficit, and depression following peripheral nerve injury in rodents.

BackgroundChronic pain is often accompanied by short-term memory deficit and depression. Currently, it is believed that short-term memory deficit and depression are consequences of chronic pain. Here, we test the hypothesis that the symptoms might be caused by overproduction of interleukin-1beta (IL-1β) in the injured nerve independent of neuropathic pain following spared nerve injury in rats and mice.ResultsMechanical allodynia, a behavioral sign of neuropathic pain, was not correlated with short-term memory deficit and depressive behavior in spared nerve injury rats. Spared nerve injury upregulated IL-1β in the injured sciatic nerve, plasma, and the regions in central nervous system closely associated with pain, memory and emotion, including spinal dorsal horn, hippocampus, prefrontal cortex, nucleus accumbens, and amygdala. Importantly, the spared nerve injury-induced memory deficits, depressive, and pain behaviors were substantially prevented by peri-sciatic administration of IL-1β neutralizing antibody in rats or deletion of IL-1 receptor type 1 in mice. Furthermore, the behavioral abnormalities induced by spared nerve injury were mimicked in naïve rats by repetitive intravenous injection of re combinant rat IL-1β (rrIL-1β) at a pathological concentration as determined from spared nerve injury rats. In addition, microglia were activated by both spared nerve injury and intravenous injection of rrIL-1β and the effect of spared nerve injury was substantially reversed by peri-sciatic administration of anti-IL-1β.ConclusionsNeuropathic pain was not necessary for the development of cognitive and emotional disorders, while the overproduction of IL-1β in the injured sciatic nerve following peripheral nerve injury may be a common mechanism underlying the generation of neuropathic pain, memory deficit, and depression.

The toxicological evaluation of repetitive 2- and 4-week intravenous injection of Activin A/BMP-2 chimera (AB204) into rats

The subchronic (28-days) toxicity of an Activin A/BMP-2 chimera (AB204) was assessed in rats. Sprague–Dawley rats received repetitive intravenous injection of AB204 in doses of 0, 0.25 and 0.5 mg/kg for two weeks and in doses of 0, 0.08, 0.16 and 0.32 mg/kg/day for four weeks. No animal was dead and no change caused by the AB204 was observed in general symptoms, weight variation, and food and water intake as well as blood test and autopsy findings. In conclusion, the no observed adverse effects level (NOAEL) of the AB204 on rats was determined to be 0.32 mg/kg/day.

Ligustilide inhibits microglia-mediated proinflammatory cytokines production and inflammatory pain.

Ligustilide is the main component of Danggui essential oil, and recently reported to have anti-inflammatory and neuroprotective effect. Increasing evidence suggests that glia-mediated neuroinflammation in the spinal cord plays a vital role in the pathogenesis of chronic pain. In the present study, we investigated the anti-inflammatory and anti-nociceptive effect of ligustilide both in vitro and in vivo. In microglial cell line BV2 cells, lipopolysaccharide (LPS) time-dependently increased the mRNA expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6), which was decreased by pretreatment with ligustilide in a dose-dependent manner. Ligustilide also decreased LPS-induced proinflammatory cytokines production in primary cultured microglia. In vivo, intrathecal injection of LPS induced mechanical allodynia in mice. Intravenous injection of ligustilide prevented LPS-induced mechanical allodynia, and decreased LPS-induced TNF-α, IL-1β, and IL-6 up-regulation in the spinal cord. In addition, repetitive intravenous injection of ligustilide attenuated intraplantar injection of complete Freund's adjuvant (CFA)-induced mechanical allodynia and thermal hyperalgesia. The same treatment of ligustilide also inhibited CFA-induced TNF-α, IL-1β, and IL-6 up-regulation and microglial activation in the spinal cord. Taken together, our data suggest that ligustilide can alleviate inflammatory pain partly through inhibition of microglial activation and proinflammatory cytokines production, which indicates a possible benefit from the use of ligustilide in the treatment of inflammatory pain and neuroinflammation-associated disorders.

Abstract 3956: CD11b Positive Monocytes Are Required for Endothelial Regeneration

Bone marrow (BM)-derived circulating endothelial progenitor cells (EPC) contribute to endothelial cell (EC) regeneration. Systemic transfusion of EPC fosters the restoration of the endothelium after EC damage in mice. Transfusion of mononuclear cells (MNC) leads to an even more pronounced endothelial regeneration compared to EPCs. Here, we determine the role of monocytic cells and their interaction with circulating EPC on EC regeneration. To evaluate the effect of monocytes on re-endothelialization, neointima formation, and endothelial function, wild-type (WT) mice received repetitive intravenous injections of spleen-derived MNC, CD11b-depleted MNC, CD11b+ monocytes, or cell-free vehicle after EC denudation. Endothelial restoration was enhanced and neointima formation reduced after transfusion of MNC and CD11b+ cells. CD11b-depleted cells had no effect. Transfusion of CD11b+ cells in ApoE−/− mice improved endothelial-dependent vasorelaxation while CD11b-depleted cells had no effect. Next, WT mice were treated with clodronate liposomes (10μl/g bw) which induces the ablation of circulating monocytes. Re-endothelialization was diminished in clodronate- compared to vehicle-treated mice. Next, we selectively depleted CD11b+ monocytes using CD11b-DTR mice which express the human diphtheria toxin receptor (DTR) under the control of the CD11b promoter. Treatment with diphtheria toxin (DT) resulted in the complete ablation of circulating monocytes. Re-endothelialization was delayed in DT-treated compared to vehicle-treated mice. Systemic treatment of WT mice with Sca1+ EPC improves endothelial function. Repetitive transfusion of Sca1+ cells enhanced re-endothelialization in vehicle-treated CD11b-DTR mice compared to DT-treated mice. Rescue experiments showed that transfusion of CD11b+ cells in CD11b-DTR mice treated with either vehicle or DT resulted in a comparable enhancement of re-endothelialization. Our results indicate that circulating CD11b+ monocytes contribute to EC regeneration. Ablation of monocytes in vivo leads to a delay in re-endothelialization after focal EC damage which can not be rescued by transfusion of Sca1+ cells.

Repetitive injections of L-glutamic acid, in contrast to those of N-methyl-D,L-aspartic acid, fail to elicit sustained hypothalamic GnRH release in the prepubertal male rhesus monkey (Macaca mulatta).

The purpose of the present study was to examine whether repetitive intravenous injections of L-glutamic acid (Glu), like those of N-methyl-D,L-aspartic acid (NMA), are able to elicit a sustained train of gonadotropin releasing hormone (GnRH) discharges from the hypothalamus of the prepubertal male monkey. In order to utilize pituitary luteinizing hormone (LH) secretion as a bioassay of hypothalamic GnRH release, the responsiveness of the gonadotroph of the prepubertal animals was enhanced prior to the study with a chronic intermittent intravenous infusion of the synthetic decapeptide (0.1 microgram/min for 3 min every h). Sequential intravenous injections of Glu (150 mg/kg BW) were administered at 3-hour intervals for 6 or 24 h. Although the first injection of this acidic amino acid elicited a robust discharge of GnRH, subsequent stimulation with Glu resulted in GnRH discharges with progressively decreasing magnitudes, and by the 9th injection Glu-induced GnRH release was abolished. Peak concentrations of circulating Glu following the 1st and 4th Glu injection were indistinguishable (3,959 +/- 437 vs. 4,139 +/- 72 nmol/ml, respectively). Interestingly, the failure of repetitive intravenous injections of Glu to sustain pulsatile GnRH release was not associated with a loss of responsiveness to NMA administration, nor was it accompanied by a corresponding decrement in Glu induced growth hormone (GH) discharges. As previously demonstrated, repetitive intravenous administration of NMA (2-5 mg/kg BW) every 3 h for 9 h sustained pulsatile GnRH secretion without decrement. A similar intermittent infusion of kainic acid (KA; 1 mg/kg BW every 3 h for 6 h), however, elicited a GnRH response that mimicked that observed in response to intermittent Glu treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of partial nephrectomy on the pharmacokinetics and pharmacodynamics of recombinant human erythropoietin (SNB-5001) in rats

The present study examined the pharmacokinetic and pharmacodynamic profiles of recombinant human erythropoietin (SNB-5001) in partially nephrectomized rats. The plasma level of SNB-5001 was measured by a 2-step enzyme immunoassay. The plasma disappearance curve after intravenous injection of SNB-5001 (50 U/kg) in these rats showed a biexponential pattern similar to that in non-treated rats, conforming to a two-compartment model. However, the total body clearance was reduced, the plasma half life was prolonged and the area under the concentration-time curve of SNB-5001 was increased by the partial nephrectomy. The distribution volumes of SNB-5001 were almost the same as those in non-treated rats. It is suggested that the kidney may contribute to the elimination of SNB-5001. Dose-dependent increases of reticulocytes, red blood cells, hemoglobin and hematocrits were observed after seven repetitive intravenous injections of SNB-5001 in both partially nephrectomized rats and non-treated rats. Hemopoietic responses were calculated by subtracting the initial values from the values after SNB-5001 injections of each hematological parameter (reticulocytes, red blood cells, hemoglobin and hematocrits). Hemopoietic responses in partially nephrectomized rats were apparently stronger than those in non-treated rats. These results suggest that the reduction of clearance by the partial nephrectomy may contribute to the hemopoietic responses, in addition to suggesting that the uremic conditions do not inhibit the effects of SNB-5001 in partially nephrectomized rats.

Localization of 131I-labeled p97-specific Fab fragments in human melanoma as a basis for radiotherapy.

33 patients with advanced malignant melanoma were studied after intravenous administration of 131I-labeled Fab fragments specific for p97, an oncofetal glycoprotein of human melanoma. In all, 47 gamma camera imaging studies were performed for the purpose of localization of metastatic deposits. In addition to tumor, 131I-Fab uptake was also seen in liver and kidney. 20 of these studies included simultaneous administration of both an 131I-labeled Fab specific for p97, and an 125I-labeled Fab not specific for p97. Blood clearance of p97-specific Fab was significantly more rapid than for nonspecific Fab. Eight of these patients had biopsies of subcutaneous nodules at 48 and 72 h postinjection in order to assess whether localization of radioactivity was antigen specific. Antigen-specific localization was observed with average ratios of specific/nonspecific uptake of 3.7 (48 h) and 3.4 (72 h); uptake was strongly correlated with tumor p97 concentration (r = 0.81, P less than 0.01). Also, imaging studies of the bio-distribution of 131I-labeled anti-p97 Fab in patients selected for high p97 tumor concentration showed avid tumor uptake and more prolonged retention of labeled Fab in tumor than in normal tissues. Based on these studies, we estimated that total 131I doses of 500 mCi could be safely given to patients before dose-limiting toxicity would be observed. Accordingly, in seven selected patients, phase I radiotherapeutic trials were begun. For improved radiation safety, we developed automated methods to label Fab fragments with up to 200 mCi of 131I. So far, a total of 12 individual therapeutic doses, ranging from 34 to 197 mCi of 131I-labeled to 5 to 10 mg of Fab, have been administered with excellent tumor localization and without major target organ toxicity. Cumulative doses ranged from 132 to 529 mCi 131I. Side effects attributable to the radiation were mild, with a transient drop slightly greater than 50% in platelet and absolute neutrophil counts being observed in the two patients who received cumulative doses greater than 500 mCi. In the combined series of 47 diagnostic and 12 therapeutic studies, four acute reactions were observed: one episode each of transient chills and fever; flushing and hypotension; and two skin rashes. All of these reactions responded promptly to symptomatic therapy. After multiple administrations of 131I-(anti-p97) Fab (IgG1), isotype-specific immunity was observed in three patients. In two of these patients it was possible to successfully reinfuse after immunity had developed with 131I-(anti-p97) Fab of a different isotype (IgG2a). Dosimetry estimates were performed based on the biodistribution of (131)I-Fab in these patients,and for every 100 mCi of (131)I-Fab given, tumor receives 1,040 rads; liver. 325 rads; and bone marrow, 30 rads. Marrow would be expected to be the critical organ, if doses >500 mCi (131)I-Fab are given. These studies demonstrated that, with proper precautions, large doses (of an (131)I-labeled murine Fab fragments immunologically specific for a human melanoma-associated antigen) could be safely given to humans by using repetitive intravenous injections.

Effect of changes in circulating amylase levels on amylase output in bile.

The relation between plasma and biliary amylase activity and their relationship to the functional state of the pancreas were studied in anesthetized rabbits. Repetitive intravenous injections of cholecystokinin resulted in a 25-fold rise in the secretion of amylase via the pancreatic duct, followed at first by a 50% increase in plasma amylase concentration and later by a 270% increase in biliary amylase concentration. There was then a gradual, roughly synchronous decline in both plasma and biliary values toward basal level despite a continued highly augmented rate of pancreatic ductal secretion. "Near-total" pancreatectomy completely abolished the effect. These observations are consistent with a cholecystokinin-induced basolateral secretion of amylase from pancreas into blood and its subsequent movement from blood into bile down a concentration gradient. The output of amylase in bile, however, was quite small and does not suggest that biliary transport of amylase has an important function either as a means of secreting and recycling digestive enzyme into the gut or as a major excretory pathway for circulating amylase in the rabbit.

Effect of covalent attachment of polyethylene glycol on immunogenicity and circulating life of bovine liver catalase.

Methoxypolyethylene glycols of 1900 daltons (PEG-1900) or 5000 daltons (PEG-5000) were covalently attached to bovine liver catalase using 2,4,6-trichloro-s-triazine as the coupling agent. Rabbits were immunized by the intravenous and intramuscular routes with catalase modified by covalent attachment of PEG-1900 to 43% of the amino groups (PEG-1900-catalase). The intravenous antiserum did not yield detectable antibodies against PEG-1900-catalase or native catalase, as determined by Ouchterlony and complement fixation methods, whereas the intramuscular antiserum contained antibodies to both PEG-1900-catalase and catalase. PEG-1900 did not react with either antiserum. Catalase was prepared in which PEG-5000 was attached to 40% of the amino groups (PEG-5000-catalase). This catalase preparation did not react with either antiserum. PEG-1900-catalase retained 93% of its enzymatic activity; PEG-5000-catalase retained 95%. PEG-5000-catalase resisted digestion by trypsin, chymotrypsin, and a protease from Streptomyces griseus. PEG-1900-catalase and PEG-5000-catalase exhibited enhanced circulating lives in the blood of acatalasemic mice during repetitive intravenous injections. No evidence was seen of an immune response to injections of the modified enzymes. Mice injected repetitively with PEG-5000-catalase remained immune competent for unmodieied catalase, and no evidence of tissue or organ damage was seen.

SOME HISTOLOGIC AND CYTOLOGIC FEATURES OF LEUKEMIAS INDUCED BY DIBUTYLNITROSAMINE IN CBA/H-T<sub>6</sub>T<sub>6</sub> MICE

Repetitive intravenous injections of a small dose of dibutylnitrosamine frequently induced acute leukemias of reticulumcell type in low-leukemic mice with an average latent period of 152 days and with an average effective dose of 244μg. Two cases of leukemias were transplantable in syngeneic hosts.Electron microscopic study revealed no virus-like particles in the leukemic cells.The modal number of chromosomes of transplanted leukemic cells shifted from 40 in earlier passages to 41 in later. Through those passages about 50 per cent of cells with 40 chromosomes and about 90 per cent of cells with 41 chromosomes had one chromosome characterized by a secondary constriction.Discussion was made on some factors responsible for leukemogenesis by dibutylnitrosamine.