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PubMedDate not supplied

Imaging of leukocytic infiltration in human cerebral infarcts.

The circulating white blood cells of patients with brain infarction were labelled in vitro with Indium-111 tropolonate; the cells were reinjected to study the inflammatory process by gamma camera imaging. Eight patients with acute cerebral ischemic infarct were studied during the first two weeks after the onset of neurological symptoms. In seven cases a well defined area of increased radioactivity was revealed in the infarcted hemisphere indicating active migration and tracking of labelled leukocytes in cerebral infarct. This method allows monitoring of the cellular inflammatory response in human cerebral infarcts and adds another imaging technique.

Acute Disease↗
PubMed1999

Antimicrobial activity and metalloprotease inhibition of hinokitiol-related compounds, the constituents of Thujopsis dolabrata S. and Z. hondai MAK.

Gamma-thujaplicin, beta-dolabrin and hinokitiol(beta-thujaplicin), hinokitiol-related compounds isolated from the wood of Thujopsis dolabrata S. and Z. hondai MAK have antimicrobial activity. In particular, strong antibacterial activity of hinokitiol and beta-dolabrin on Staphylococcus epidermidis IFO-12993 was found, with a minimum inhibitory concentration (MIC) of 0.2 microg/ml. This activity was higher than that of gentamicin, used as a positive control, and so the strong antibacterial activity of both compounds on this bacterium is of considerable interest. Of the three compounds, gamma-thujaplicin showed the strongest antifungal activity and its MIC was found to be around 1.5 microg/ml. The three compounds also inhibited metalloproteases. The inhibitory activity of hinokitiol on carboxypeptidase A was especially strong, its 50%-inhibitory concentration (IC50) being 2.76x10(-6) M. Considering that metalloproteases are involved in inflammation, the strong inhibitory activity of hinokitiol could be important. On the other hand, hinokitiol-acetate did not show any antimicrobial activity and metalloprotease inhibition, suggesting that at least part of the activity is due to metal chelation between the carbonyl group at C-1 and the hydroxyl group at C-2 in the tropolone skeleton.

Anti-Bacterial Agents↗
PubMed2001

Cytotoxicity of the hinokitiol-related compounds, gamma-thujaplicin and beta-dolabrin.

Gamma-thujaplicin and beta-dolabrin, the constituents of the wood of Thujopsis dolabrata Sieb. et Zucc. var. hondai showed strong in vitro cytotoxic effects against the human stomach cancer cell lines KATO-III and Ehrlich's ascites carcinoma. The cytotoxic effects of the two compounds against both tumor cell lines were clear when cell growth was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Gamma-thujaplicin and beta-dolabrin at 0.32 microg/ml inhibited cell growth of human stomach cancer KATO-III by 85 and 67%, and Ehrlich's ascites carcinoma by 91 and 75%, respectively. There is no large difference in cytotoxicity between these compounds, but the activity of gamma-thujaplicin was slightly more potent than that of beta-dolabrin. On the other hand, hinokitiol acetate did not show a cytotoxic effect, suggesting that at least a part of the mechanism of the cytotoxic effect of hinokitiol-related compounds is due to metal chelation between the carbonyl group at C-1 and the hydroxyl group at C-2 in the tropolone skeleton of these molecules. The acute toxicities [50% lethal dose (LD50) value: intraperitoneal injection, Van der Waedem] of gamma-thujaplicin and beta-dolabrin in mice were 277 mg/kg and 232 mg/kg, respectively.

Animals↗
PubMed1997

Biological activity of purpurogallin.

Purpurogallin showed antibacterial activity toward gram-positive bacteria. Strong activity against methicillin-resistant Staphylococcus aureus [minimal inhibitory concentration (MIC) against methicillin of 1600 micrograms/ml] was found, with MIC of 11.0 micrograms/ml. Purpurogallin inhibited the growth of all tested plants and decreased the chlorophyll content in the cotyledons of Brassica campestris subsp. rapa. It showed potent inhibitory activity against prolyl endopeptidase (the 50% inhibitory concentration was 1.6 x 10(-5) M), unlike its analogues, hinokitiol and tropolone.

Anti-Bacterial Agents↗
PubMed1999

Inhibitors of inositol monophosphatase.

Inositol monophosphatase (IMPase) catalyses the hydrolysis of myo-inositol monophosphates to myo-inositol, which is required in the phosphatidyl inositol cell signalling pathway. Here the enzyme structure, mechanism and inhibition of IMPase are reviewed. Lithium, an effective therapy for manic depression, is an uncompetitive inhibitor. In the search for alternative inhibitors to lithium, substrate-based inhibitors, bisphosphonates, terpenoid and tropolone analogues are described.

Inositol↗
PubMed1976

Role of neuronal and extraneuronal factors in temperature mediated responsiveness of adrenoceptors.

Changes in bath temperature caused changes in the adrenergic responsiveness of rabbit iris dilator muscle as indicated by shifts in dose-response curves along the log axis and changes in maximum responses. Responses of control tissues to an alpha agonist (norepinephrine) were increased at lower temperatures and responses to a beta agonist (isoprenaline) were increased at higher temperatures. Responses of control tissues were compared with responses of tissues pretreated with cocaine or with responses of adrenergically denervated tissues (chemical and surgical). Changes in ED50 values with temperature change are similar in control, cocaine pretreated or denervated muscles. In contrast, changes in maximum response with temperature change are reversed by cocaine pretreatment or denervation. Pretreatment of tissues with an inhibitor of catechol-o-methyl transferase (tropolone) or an inhibitor of monoamine oxidase (iproniazid) did not affect the temperature sensitivity of adrenoceptors. Also, responses to terbutaline, a beta agonist not susceptible to catechol-o-methyl transferase, changed with temperature. These data indicate that for rabbit iris dilator muscle both a neuronal and an extraneuronal component are involved in adrenoceptor response changes induced by temperature change and that changes in rates of activity of metabolizing enzymes are not involved.

Animals↗
PubMedDate not supplied

Platelet preservation during cardiopulmonary bypass with iloprost and Duraflo-II heparin-coated surfaces.

To test the hypothesis that temporary platelet inhibition during cardiopulmonary bypass (CPB) with surface heparinized systems may result in platelet preservation, nine Yorkshire pigs were placed on CPB for 3 hours. Platelet labeling was done in all pigs with Indium-111 tropolone. CPB was instituted with a roller pump, a hollow fiber membrane oxygenator (Bentley CM-50 [Baxter-Bentley Laboratories, Irvine, CA]), and an arterial filter. The extracorporeal perfusion systems were surface-coated with the Duraflo-II heparin complex. Group A pigs (n = 5) were systemically heparinized (activated coagulation time longer than 400 sec). Group B pigs (n = 4) were placed on CPB without systematic heparinization, but have received the stable prostacyclin-analog Iloprost (ZK36374) at 1 ng/kg/min i.v. from 30 min before and during CPB. Platelet counts declined in group A pigs at 5 min, 1 hr, 2 hr, and 3 hr of CPB to 79.8% (mean), 66.5%, 71.3%, and 69.0% of pre-CPB values, respectively (p less than 0.05). In group B pigs, mean platelet count during CPB was higher than 90% of control value. Percentage of injected radioactivity detected in the oxygenator was 2.82% in group A pigs versus 0.73% in group B pigs (p = 0.0541). Surface heparinization with the Duraflo II heparin coating complex in combination with Iloprost-induced temporary platelet inhibition resulted in platelet count preservation during CPB in the pig model.

Animals↗
PubMed1990

[Experimental studies on the pathogenesis of adult respiratory distress syndrome using 111In-labeled polymorphonuclear leukocytes].

This study was undertaken to clarify the mechanism of the development of ARDS and to improve its treatment by studying the role of polymorphonuclear leukocytes (PMNs) in an endotoxin shock model of rats. PMNs from a rat were labeled with 111In by the use of tropolone and were injected into rats pretreated with endotoxin. Then the biodistribution of PMNs was studied by either counting the radioactivity of excised organs or using a gamma scintillation camera on the anesthetized rats. The two methods facilitated to observe the distribution of PMNs fairly a short time after the injection of endotoxin. There was a significantly higher radioactivity in the lungs of the endotoxin group than in the control group. The accumulation of PMNs into the lungs occurred immediately after endotoxin injection. In rats depleted of the complement by cobra venom factor (CVF), an increase in radioactivity in the lung was not observed. These results indicate that the complement system is involved in the pathogenesis of ARDS. When rats were injected with methylprednisolone, the pulmonary accumulation of 111In-PMNs by endotoxin were suppressed. This is an experimental support of possible beneficial effects of corticosteroids in the treatment of ARDS.

Animals↗
PubMed1988

[Influence of endogenous catecholamines on responses of rat lung to beta-adrenergic agonists].

Relaxation responses to the beta-adrenoceptor agonists: isoprenaline (non selective), salbutamol (beta 2-selective) and noradrenaline (plus phentolamine 10(-5) M) (beta 1-selective) have been obtained on rat lung parenchymal strips in the absence and presence of pargyline and tropolone (monoamino-oxidase and catechol-O-methyltransferase inhibitors), cocaine (neuronal uptake blocking agent), corticosterone (extraneuronal uptake inhibitor) as well as in reserpinized rat. Responses to these beta-adrenergic agonists were not potentiated in the presence of any of these inhibitors. This indicates that endogenous catecholamines, enzymatic or uptake processes, do not modulate beta-adrenoceptor mediated responses of rat lung strip and demonstrates that there is no correlation between neuronal uptake/beta 1-adrenoceptors and extraneuronal uptake/beta 2-adrenoceptor mediated responses, as had previously been suggested.

Adrenergic alpha-Agonists↗
PubMed1987

Mechanism of ionophoric transport of indium-111 cations through a lipid bilayer membrane.

The use of mobile ionophores to facilitate the transport of 111In through a lipid bilayer membrane has broad applications in liposome technology and cell labeling. However, the mechanism of such ionophore-mediated transport of 111In through a lipid bilayer membrane is not completely clear. The present report describes the correlations of the behaviors of ionophoric loading of 111In into liposomes with the lipophilicity and the indium-binding affinity of three ionophores, namely, 8-hydroxyquinoline, acetylacetone, and tropolone. Our results suggest that the mechanism of the ionophoric transport of 111In through a lipid bilayer membrane involves the rapid exchange of 111In cations among the ionophores in both the aqueous solution and the lipid bilayer. Furthermore, the effectiveness of an ionophore in facilitating the transport of 111In from the external aqueous compartment to the entrapped nitrilotriacetic acid depends not only on the lipophilicity of the [111In]ionophore complex, but also on the lipophilicity of the free ionophore itself and the competition of 111In between nitrilotriacetic acid inside the inner aqueous compartment of the liposome and the ionophore imbedded in the lipid bilayer membrane of the liposome.

Animals↗
PubMed1987

Effects of chelates and incubation media on platelet labeling with indium-111.

We studied the effects of various [111In]chelates and incubation media on labeling efficiency (LE) and in vivo survival of platelets. High LE of human and rabbit platelets in plasma were obtained with [111In]tropolone and [111In]mercaptopyridine-N-oxide. Indium-111 oxine in plasma resulted in a moderate LE and required a longer incubation time, while [111In]oxine sulfate had low LE and inconsistent labeling. High LE for all forms of [111In]chelates were achieved in labeling media free of plasma. However, in vivo platelet survival in rabbits was markedly reduced when platelets were labeled in the absence of plasma.

Animals↗
PubMed1988

Potential use of indium-111-labeled polymorphonuclear leukocytes for the detection of lung microvascular injury.

The early stages of microvascular injury are often difficult to detect due to the lack of a suitable marker to assess such an injury. We utilized the well known phenomenon of polymorphonuclear leukocyte (PMN) migration to the microvascular bed as a result of acute inflammatory reactions originating from the damaged cells. A radiotracer technique was developed, employing indium-111-labeled PMN for the detection of microvascular injury induced by hyperoxia. New Zealand white rabbits exposed to either 100% oxygen or air for various intervals of time were injected with indium-111-tropolone or oxine-labeled PMNs. Influx of radioactive PMN into the lung was detected in 72 hr/oxygen-exposed animals using gamma scintigraphic technique. Analysis of dry/wet ratios and histological examinations of the lung biopsies indicated noncardiogenic edema formation at this stage. Mortality was 50% beyond 96 hr/oxygen exposure. Our study thus provided a means to detect early microvascular injury during 72 hr/oxygen-exposure, which was not detectable by any other noninvasive techniques. The use of indium-111-labeled PMN thus appears to be a potentially important tool for the clinical assessment of lung microvascular injury.

Animals↗
PubMed1988

Migratory patterns of different indium-111 labeled leukocyte populations (chiefly lymphocytes) from control and thymectomized rats.

The blood clearance and 24-hr organ distribution of five lymphocyte-rich suspensions harvested from different source organs were compared in the Wistar rat, after labeling with [111In]tropolone and intravenous injection. Peripheral blood lymphocytes (chiefly T cells) had the highest levels in the blood and lymph nodes, a relatively higher level in intestine and a lower level in the spleen than other suspensions. Thymocytes cleared promptly from the blood, accumulated markedly in the liver, moderately in the spleen, but very poorly in other organs, including the thymus. Splenic cells (rich in B cells) sequestered predominantly in the spleen and liver. Splenic cells nonadherent to nylon wool (T-cell enriched) had a relatively high uptake in lymph nodes and marrow. Splenic cells from thymectomized rats (NK cell enriched) localized predominantly in the liver and spleen, and poorly in lymph nodes. We conclude that the source organ for harvesting rat lymphocytes is an important determinant in their localization, as well as other factors such as the techniques of isolation, the toxicity and stability of the radioactive label and the cell radiation dose from internalized radioactivity.

Animals↗
PubMed1985

Homing and circulation of indium-111-labelled leucocytes. A post-mortem study.

The history of a patient with a suspected ischemic brain infarct undergoing an indium-111-tropolone white cell labelled test is reported. The patient, who died 12 h after injection of the labelled cells, suffered of a brain haemorrhage. The post-mortem examination has allowed for the first time the measurement of radioactivity in different organs following the injection of indium-111-labelled leucocytes. High radioactivity was found only in tissues affected by inflammatory processes and in the lymphonodes draining the corresponding areas. This report clearly indicates the importance of this method for the study of white cell localization and circulation to the sites of infections.

Cerebral Hemorrhage↗
PubMed1985

Gallium-68 lipophilic complexes for labeling platelets.

Generator produced 68Ga-labeled platelets could be useful for positron emission tomographic (PET) studies of thrombosis or atherosclerosis. To label platelets with 68Ga, we have studied the effects of trace metals in elutions of 68Ga from 68Ge. Studies were conducted on the formation of lipophilic 68Ga complexes 8-hydroxyquinoline, tropolone, and mercaptopyridine-N-oxide (MPO). Parameters such as pH, buffers, concentration of ligand, and stability with time were investigated. High performance liquid chromatography and instant thin layer chromatography were used to quantitate formation of the 68Ga complex. Platelets from human, dog, and rabbit plasma were incubated with the 68Ga complexes and the percent labeling determined. Accumulation of platelets in the catheter scraped aorta of the rabbit was determined by PET imaging, tissue counting, and autoradiography. Gallium-68 MPO gave 40-60% labeling of rabbit platelets with higher accumulation in the scraped aorta compared to the normal.

Animals↗
PubMed1985

Intrahepatic kinetics of indium-111-labelled platelets.

The intrahepatic kinetics of 111indium-labelled platelets have been studied using dynamic gamma camera scintigraphy immediately following injection. Platelets labelled in saline with 111In-oxine or 111In-acetylacetonate underwent rapidly reversible hepatic sequestration, indicating that they were "activated". Platelets labelled in plasma with 111In-tropolonate, however, did not display this phenomenon. On the assumption that plasma-labelled platelets display a normal initial bio-distribution, mean intrahepatic platelet transit time, as a factor of the transit time of 99m-Tc labelled red cells, was 1.45 +/- SE 0.12 (n = 6), implying the normal presence of a small intrahepatic platelet pool. Unlike the liver, transit through the spleen was not sensitive to the labelling medium; thus the mean intrasplenic transit time of plasma-labelled platelets was 9.3 +/- SE 0.7 min (n = 10), and of saline-labelled platelets 9.5 +/- SE 0.3 min (n = 8).

Blood Platelets↗
PubMed1984

A functional comparison of IIIindium-labelled elicited peripheral blood neutrophils and peritoneal neutrophils in the rat.

A functional comparison between elicited peripheral blood neutrophils has been made in vivo and in vitro. Preliminary experiments showed that separation of peripheral blood cells on a metrizamide gradient yielded too few neutrophils for efficient radiolabelling with indium (In): hence a mixed cell preparation comprising 80% neutrophils was elicited in the peripheral blood of adult male rats by the administration of endotoxin (0.25 mg i.a.) and cobra venom factor (200 microliter i.p.) 20 h before. Peritoneal neutrophils were collected 4 h after the i.p. injection of 6 ml thioglycollate. Both populations differed markedly from normal peripheral neutrophils on the in vitro testing of random locomotion, chemotaxis and phagocytosis of Candida. After labelling with IIIIn-tropolonate, a greater proportion (mean = 8%) of peripheral blood cells localized to an E. coli/Freund's complete adjuvant-induced abscess compared with peritoneal neutrophils (mean = 3%). The abscess could be visualized externally by scanning with both cell preparations, but the distribution of activity differed markedly. The greater hepatic sequestration of peritoneal neutrophils suggested cell damage or activation. To overcome the difficulty of harvesting normal peripheral blood neutrophils in the rat, either of these populations can be used to follow the kinetics of inflammation. However, elicited peripheral blood cells yield a higher proportion of responding cells.

Abscess↗
PubMed1983

New "ex vivo" radioisotopic method of quantitation of platelet deposition - studies in four animal species.

We have developed a sensitive and quantitative method of "ex vivo" evaluation of platelet deposition on collagen strips, from rabbit Achilles tendon, superfused by flowing blood and applied it to four animal species, cat, rabbit, dog and pig. Autologous platelets were labeled with indium-111-tropolone, injected to the animal 24 hr before the superfusion and the number of deposited platelets was quantitated from the tendon gamma-radiation and the blood platelet count. We detected some platelet consumption with superfusion time when blood was reinfused entering the contralateral jugular vein after collagen contact but not if blood was discarded after the contact. Therefore, in order to have a more physiological animal model we decided to discard blood after superfusion of the tendon. In all species except for the cat there was a linear relationship between increase of platelet on the tendon and time of exposure to blood superfusion. The highest number of platelets deposited on the collagen was found in cats, the lowest in dogs. Ultrastructural analysis showed the platelets were deposited as aggregates after only 5 min of superfusion.

Animals↗