bluuebunny/crossref_metadata_2025 huggingface dataset:
Close Localization of Mouse CD14 and CD32/16 in the Cell Surface of Monocytic Cell Lines
Authors: Hisaka Hiroshi , Kataoka Masashi , Higuchi Yasunori , Matsuura Keiko , Yamamoto Shunsuke
Published: April 2003

The binding of a rat anti-mouse CD14 monoclonal antibody (mAb) (rmC5-3) was inhibited by pretreatment of a mouse monocytic cell line WEHI-3 cells with anti-mouse CD32/16 mAb (2.4G2), whereas that of 2.4G2 was not inhibited by pretreatment of WEHI-3 cells with rmC5-3. An enzyme-linked immunosorbent assay showed that rmC5-3 detected peptide 9 corresponding to amino acid position 308–322 of CD14 but 2.4G2 did not. A Western blot analysis of sera revealed that rmC5-3 and 2.4G2 detected the bands thought to be soluble CD14 and CD32/16, respectively. rmC5-3 reacted with mouse CD14-transfected CHO cells, CD14-CHO-K1 cells, but 2.4G2 did not. Lipopolysaccharide-induced tumor necrosis factor (TNF)-α release was enhanced when a monocyte cell line (J774) was pretreated with rmC5-3. The enhancement was abolished by pretreatment with 2.4G2. The release of TNF-α was observed following treatment of J774 cells with 2.4G2 followed by anti-rat IgG F(ab′)2.
Comparative Analysis of the Reactivity of Human Umbilical Vein Endothelial Cells in Organ and Monolayer Culture
Authors: Müller AnnetteM. , Cronen Claus , Müller Klaus-Michael , Kirkpatrick C.James
Published: April 2003

Endothelial monolayer cell cultures have been used to study pathomechanisms under standardized in vitro conditions. These results can only be regarded as valid as long as phenomena studied in vitro are comparable to findings in situ, e.g. in organ culture. The aim of the present study was to examine the reliability and comparability between human umbilical vein endothelial cells (HUVEC) in a monolayer cell culture model and endothelial cells (EC) in organ culture, as well as in the native umbilical cord. Our results prove the reliability of HUVEC as a model for standardized investigations of EC. The differences found suggest that gradual differences in antigen expression in vitro and in situ become apparent by comparing in situ and in vitro investigations.
Effect of Cytotoxic Chemotherapy on Serum Lipid Levels in Breast Cancer Patients
Authors: Rzymowska Jolanta
Published: April 2003

Seventy patients with breast cancer at various clinical stages and 15 patients with fibroadenoma were investigated. After chemotherapy, a significant increase in total triglycerides in malignant breast cancer patients before and after menopause has been observed. The increase in total cholesterol was not significant after chemotherapy. The levels of LDL and HDL cholesterol were significantly decreased in pre- and postmenopausal women treated with chemotherapy.
In situ Detection of Human Monocyte/ Macrophage Serine Esterase-1 mRNA Expression in Human Tissues
Authors: Satoh T. , Hemmerlein B. , Zschunke F. , Radzun H.J.
Published: April 2003

Human monocyte/macrophage serine esterase (HMSE) can be distinguished from esterases of other blood cells by a specific isoelectric focusing pattern of five enzyme variants. Using a HMSE-1 cDNA, expression of mRNA was investigated by nonradioactive in situ hybridization of human biopsy specimens and cytospin preparations. HMSE-1 transcripts could be detected in the myelomonocytic cell line U-937, blood monocytes and in tissue macrophages. Immune accessory cells of the monocyte/macrophage lineage did not express detectable amounts of HMSE-1 mRNA. These results indicate that HMSE-1 represents a cell-lineage-specific enzyme which can be used to characterize physiological and neoplastic variants of the human monocyte/macrophage cell system. The method described will enable further insight into the physiological function of HMSE-1.
Expression of Cell-Cycle-Regulating Transcription Factor E2F-1 in Colorectal Carcinomas
Authors: Yasui Wataru , Fujimoto Junya , Suzuki Tetsuo , Ono Shigehiro , Naka Kazuhito , Yokozaki Hiroshi , Tahara Eiichi
Published: April 2003

The expression of E2F-1 in human colorectal carcinomas was examined immunohistochemically, and the correlation of E2F-1 expression with clinicopathological findings and with the expression of p27Kip1 was analyzed to elucidate the role of E2F-1 in the development and progression of colorectal carcinomas. In nonneoplastic mucosa, a small number of epithelial cells in the proliferative zone were weakly positive for E2F-1. Weak expression of E2F-1 was detected in many adenoma cells. Most of the colorectal carcinomas expressed E2F-1 at various levels, and strong expression of E2F-1 was detected in 56% (49/88) of the cases. There was no correlation between the expression of E2F-1 and any clinicopathological parameters such as tumor stage, depth of tumor invasion and lymph node metastasis. Reduced expression of p27Kip1 was confirmed to be significantly correlated with deep tumor invasion and presence of metastasis. No correlation was evident between overexpression of E2F-1 and reduced p27Kip1 expression.
Stimulatory and Inhibitory Maturation of Human Macrophage-Derived Dendritic Cells
Authors: Chakraborty Abalokita , Li Li , Chakraborty Nitya G. , Mukherji Bijay
Published: April 2003

Circulating human macrophages are often used to generate dendritic cells (DCs) by culturing them in granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4). As DCs are superb antigen-presenting cells, these types of myeloid DCs are now used in many DC-based vaccination protocols, especially in cancer, with the belief that they are essentially stimulatory or ‘immunogenic’. Here we show that just as peripheral macrophage-derived myeloid DCs can be stimulatory, in vitro cultures of myeloid DCs in GM-CSF and IL-4 followed by further maturation in interferon-γ plus bacterial superantigens (as DC maturing agents) can give rise to DCs that are functionally inhibitory. The stimulatory DCs express higher amounts of costimulatory molecules, synthesize IL-12, and efficiently stimulate naive allogeneic T cells in mixed lymphocyte reaction (MLR). The inhibitory DCs, in contrast, express lower concentrations of the critical costimulatory molecules, synthesize large amounts of IL-10, and are either marginally stimulatory or nonstimulatory in MLR. Moreover, while the stimulatory DCs further amplify proliferation of T cells in lectin-driven proliferation assays, the inhibitory DCs suppress T cell proliferation in similar assays, in vitro. Most interestingly, neutralization of the endogenously derived IL-10 with anti-IL-10 antibody with DC cultures as well as exposure of the inhibitory DCs to CpG oligonucleotides or to in vitro activated autologous CD4+ T helper cells repolarize them into stimulatory phenotype. Accordingly, these observations have important implications in translational research involving myeloid DCs.
M-DC8+ Leukocytes – A Novel Human Dendritic Cell Population
Authors: Schäkel Knut , Poppe Claudia , Mayer Elfriede , Federle Christine , Riethmüller Gert , Rieber Ernst Peter
Published: April 2003

Dendritic cells (DC) constitute a heterogeneous leukocyte population having in common a unique capacity to induce primary T cell responses and are therefore most attractive candidates for immunomodulatory strategies. Two populations of blood DC (CD11c+ CD123dim and CD11c– CD123high) have been defined so far. However, their direct isolation for experimental purposes is hampered by their low frequency and by the lack of selective markers allowing large scale purification from blood. Here we describe the monoclonal antibody (mAb) M-DC8, which was generated by immunizing mice with highly enriched blood DC. This mAb specifically reacts with 0.2–1% of blood leukocytes and enables their direct isolation by a one-step immunomagnetic procedure from fresh mononuclear cells. These cells can be differentiated from T cells, B cells, NK cells and monocytes using lineage-specific antibodies. M-DC8+ cells express HLA class II molecules, CD33 and low levels of the costimulatory molecules CD86 and CD40. Upon in vitro culture M-DC8+ cells spontaneously mature into cells with the phenotype of highly stimulatory cells as documented by the upregulation of HLA-DR, CD86 and CD40; in parallel CD80 expression is induced. M-DC8+ cells display an outstanding capacity to present antigen. In particular, they proved to be excellent stimulators of autologous mixed leukocyte reaction and to activate T cells against primary antigens such as keyhole limpet hemocyanin. Furthermore, they induce differentiation of purified allogeneic cytotoxic T cells into alloantigen-specific cytotoxic effector cells. While the phenotypical analysis reveals similarities with the two known blood DC populations, the characteristic expression of FcγRIII (CD16) and the M-DC8 antigen clearly defines them as a novel population of blood DC. The mAb M-DC8 might thus be a valuable tool to determine circulating DC for diagnostic purposes and to isolate these cells for studies of antigen-specific T cell priming.
Role of Antigen-Presenting Cells in Long-Term Antitumor Response Based on Tumor-Derived Apoptotic Body Vaccination
Authors: Henry F. , Bretaudeau L. , Hequet A. , Barbieux I. , Lieubeau B. , Meflah K. , Grégoire M.
Published: April 2003

Cellular therapy prospects for cancer are based on the development of T cell response, resulting in efficient tumor rejection and long-term protection. We have previously shown that treatment combining injection of interleukin-2 and tumor-derived apoptotic bodies, but not tumor cell extracts, permits to reject parental tumor in 40% of rats. We observed the implication of antigen-presenting cells (APCs) and tumor-derived apoptotic bodies in the rejection of established peritoneal carcinomatosis. We demonstrated that apoptotic bodies could be efficiently phagocytosed by monocytes, triggering them to an APC phenotype. When using these phagocytosing APCs, derived from peritoneal or blood monocytes, the remission rate reached 80% of rats. However, due to the lack of specific markers of rat monocyte-derived cells, the precise role of APCs, dendritic cells and/or macrophages responsible for this therapeutic improvement remained to be clarified. In order to elucidate this question, we developed an in vivo preventive cellular therapy based on tumor-derived apoptotic bodies, where macrophages were either depleted or activated. We report here that in a preventive antitumoral apoptotic body vaccination that allows survival for 40% of treated rats, the antitumor response was characterized by a specific long-term memory (cured rats rejected a second parental tumor cell challenge). Depletion of resident macrophages with silica or clodronate liposomes appeared to promote apoptotic body vaccination efficiency, increasing the treatment to 66% of success. In this case, FACS analysis showed that peritoneal cells present are essentially immature APCs and freshly recruited NK cells. In contrast, the onset of peritoneal inflammation by thioglycollate, inducing massive recruitment and activation of macrophages, reduced the overall survival, whatever the treatment was. Also, even though the surviving rate was better in silica-treated rats than control, no long-term protection was elicited. Our data suggest that massive inflammation, recruiting numerous activated macrophages, could inhibit tumor antigen presentation by ‘professional’ APCs having phagocytosed apoptotic bodies, and defavor a specific antitumoral T cell response. Although effective responses were developed against parental tumor cells with silica/apoptotic body treatment, they seemed only partial, limited to primary cytotoxic efficiency. In conclusion, even if macrophages did not appear necessary for a primary response to tumor cells, these cells seemed to be implicated in the establishment of memory and long-term antitumor response.
Alternative versus Classical Activation of Macrophages
Authors: Goerdt Sergij , Politz Oliver , Schledzewski Kai , Birk Robert , Gratchev Alexej , Guillot Pierre , Hakiy Nahid , Klemke Claus-Detlev , Dippel Edgar , Kodelja Vitam , Orfanos Constantin E.
Published: April 2003

In parallel to the Th1/Th2 paradigm, antigen-presenting cells (APC) are divided into classically activated APC (dendritic cells/effector macrophages) and alternatively activated APC (IL-4-induced, alternatively activated macrophages/IL-10-induced, immature dendritic cells). Alternatively activated APC share a special molecular repertoire including receptors of innate immunity with broad specificity for foreign antigen and anti-inflammatory cytokines such as IL-1Ra and alternative macrophage activation-associated CC-chemokine-1. Alternatively activated APC mediated tolerance and downregulated inflammation. Abuse of alternatively activated APC in support of infectious susceptibility or tumor immune escape is counteracted by the classical pathway. Thus, classically and alternatively activated APC secure the balance between proinflammatory and anti-inflammatory immune reactions.
Microdissection of Tissue Sections: Application to the Molecular Genetic Characterisation of Premalignant Lesions
Authors: Walch Axel , Komminoth Paul , Hutzler Peter , Aubele Michaela , Höfler Heinz , Werner Martin
Published: April 2003

The characterisation of the early molecular genetic events of tumor development depends on the selective procurement of histopathologically defined small cell populations from premalignant tissue. In order to obtain high-quality DNA, mRNA and proteins from these small tissue samples and even from single cells, tissue microdissection is one of the most useful techniques, becoming increasingly important for molecular pathologists. Using different microdissection techniques which allow the isolation of morphologically defined cell populations under direct visualisation, it is now feasible to study molecular genetic events that drive the multistep evolution in tumours. This review aims to present the current techniques of tissue microdissection and these techniques are discussed in the light of their ability to isolate premalignant cell populations in particular. Furthermore, we describe the subsequent application of several multiplex molecular analyses for characterising the microdissected premalignant cells. Applying these advanced techniques, alterations in the cellular DNA or the fluctuation of expressed genes that correlate with a particular stage of carcinogenesis can ultimately be compared within or between individual patients. Thus, these new technologies will have an enormous impact on molecular pathology with several diagnostic, prognostic and therapeutic implications.
Divergent Selection for Pentobarbital-Induced Sedation Times in Mice
Authors: Stino Farid K.R. , Samaan Saber S. , Kolta Malak G. , Mizinga Kemmy M. , Soliman Karam F.A.
Published: April 2003

Divergent selection for pentobarbital sedation-time response was practiced in mice for 9 generations. At the end of 9 generations of selection, the long-sedation-time line (LST) slept an average of 433 min; the short sedation time line (SST) slept an average of 29 min. The control line (C) slept an average of 71 min. These differences represent an almost 15-fold increase in sedation time for the LST compared to the SST line and a 6-fold increase compared to the C line. The SST line slept about 40% less than the C line after 9 generations of selection (measured in tenth generation progeny). Analysis of selection differentials and realized heritabilities indicated that selection response did not diminish after 9 generations of selection. Realized heritabilities for sedation time ranged from 0.43 to 0.83 for the LST line and from 0.55 to 0.81 for the SST line. Realized heritabilities did not decrease in magnitude due to selection progress, indicating that more progress can still be achieved. Comparing corrected (for environmental factors) to uncorrected heritabilities showed the importance of including a control line in selection experiments. Crossing of lines to study gene action responsible for this trait revealed that this trait was controlled by a number of genes with additive gene action without dominance, overdominance, epistasis, or maternal effects.
Physiological Effects of Macrocycle 1 on the Rabbit Corpus cavernosum
Authors: Liu Shih-Ping , Hass Martha A. , Horan Patrick , Levin Robert M.
Published: April 2003

When the penis is in the flaccid state, the corpus cavernosum smooth muscle is under adrenergic control in order to maintain the sinusoids in a contracted condition (primarily via α-adrenergic stimulation). Penile erection is mediated by relaxation of corporal smooth muscle through a variety of direct and indirect mechanisms. Pharmacological agents that either inhibit α-adrenergic transmission or facilitate corporal smooth muscle relaxation will be beneficial for penile erection. Preliminary studies on macrocycle 1, a novel bioactive agent, demonstrated that this compound inhibits receptor-stimulated contraction without significantly altering field-stimulated contraction. The current study was designed to determine the physiological effects of macrocycle 1 on the response of the rabbit corpus cavernosum to various forms of stimulation. Sexually mature male New Zealand White rabbits were used in this study. The corpus cavernosum was dissected sharply from the removed penis and two longitudinal strips were prepared for isometric tension studies. Each strip was prestimulated with 200 µmol/l phenylephrine to produce a maximal contraction. The influences of macrocycle 1 (15.6, 62.5, 250, 1,000 µmol/l) on both the contractile response to phenylephrine and the relaxant effects of field stimulation, carbachol, ATP and nitroprusside were determined. The results demonstrated that although basal tension was not altered, the contractile response to phenylephrine was decreased by 5, 18, 47 and 57%, respectively, by the different concentrations of macrocycle 1. The degree of relaxation induced by field stimulation of various frequencies was significantly enhanced by macrocycle 1 in a concentration-dependent manner. Similarly, the degrees of relaxation induced by bethanechol, ATP and nitroprusside were all significantly enhanced in a concentration-dependent manner. The conclusion from this study is that macrocycle 1 significantly inhibits phenylephrine-stimulated contraction and significantly enhances field-stimulated and pharmacologically induced relaxation. Although the mechanisms of action are not clear, its physiological effects on the rabbit corpus cavernosum implicate a potential for the treatment of erectile dysfunction.
Antiprogestin-Mediated Inactivation of Cytochrome P450 3A4
Authors: Jang Graham R. , Benet Leslie Z.
Published: April 2003

Based on previous observations of very short periods of linearity for antiprogestin metabolite formation and the presence of a common tertiary amine moiety in each compound as the principal site of their metabolism, we hypothesized that mifepristone, lilopristone and onapristone are oxidized by cytochrome P450 (CYP) 3A4 to reactive nitroso species that complex the heme of the enzyme, thereby inactivating it. Upon preincubation with human liver microsomes in the presence (but not the absence) of NADPH, mifepristone inhibited midazolam 1′-hydroxylation, a marker of CYP3A4 catalytic activity, very potently (IC50 ∼3.5 µmol/l) and extensively (by ∼87%). Lilopristone and onapristone also displayed NADPH and time-dependent inactivation of CYP3A4 with characteristics very similar to mifepristone. These data support antiprogestin-mediated inactivation of CYP3A4 and suggest the potential for drug-drug interactions and time-dependent nonlinearities in pharmacokinetics upon their long-term administration.
Impaired Contraction and Relaxation in the Aorta of Streptozotocin-Diabetic Rats
Authors: Utkan T. , Sarioglu Y. , Yildirim S.
Published: April 2003

It is known that diabetes mellitus alters the vascular responsiveness to several vasoconstrictors and vasodilators. Endothelium-derived nitric oxide is a potent endogenous nitrovasodilator, and endothelin-1 (ET-1) is a potent endothelium-derived vasoconstrictor substance. They play a major role in the modulation of vascular tone. Selective impairment of endothelium-dependent relaxation and impaired vasoconstriction in response to ET-1 could result in vascular disorders. The purpose of our study was to determine whether vascular responses to ET-1 and endothelium-dependent relaxing substances are impaired in rats with streptozotocin-induced diabetes of 2 weeks duration. Endothelium-dependent relaxations produced by carbachol and ATP in aortic rings precontracted with phenylephrine were significantly attenuated in rings from diabetic rats, but the endothelium-independent relaxations produced by sodium nitroprusside and adenosine in diabetic preparations were not changed when compared to the corresponding controls. The ET-1-induced contractions were significantly attenuated with no change in agonist potency (pD2 value) in aortae with and without endothelium obtained from diabetic rats when compared to those from controls. Mechanical removal of the endothelium did not significantly change ET-1 responses of aortae from either diabetic or control rats compared with responses of aortae with intact endothelium. These results suggest that, in this diabetic model, the contractile responsiveness of thoracic aortic muscles and the endothelial functions are significantly altered during 2 weeks of diabetes.
Digital Analysis of the Pharmacological Effects of in vitro Ischemia on Rabbit Corpus cavernosum
Authors: Liu Shih-Ping , Horan Patrick , Levin Robert M.
Published: April 2003

Purpose: Regulation of corporal smooth muscle tone is essential for the initiation of penile erection. In recent years, in vitro isometric tension studies using isolated corpus cavernosal tissue have been used extensively to investigate the mechanisms regulating corporal smooth muscle tone and tension. In the present study, we utilized digital analysis of contractile data generated from investigation of contractile and relaxation responses of isolated rabbit corpus cavenosum to various forms of stimulation. Digital analysis of the contractile and relaxation data allows quantitation of both maximal and mean rates of tension change, and time elapsed to maximal response. Rates of tension changes may provide additional important information regarding cellular events that mediate corporal tone and tension changes. Methods: Sexually mature male New Zealand White rabbits were used. Each corpus cavernosum was dissected sharply from the removed penis, then two longitudinal strips were prepared for isometric tension studies and placed in individual baths. Tension was monitored continually using an 8-channel Grass Polygraph. The Grass PolyVIEW system simultaneously converted analog signals to digital information and stored data using a 486 PC computer. Each corporal strip was prestimulated with 300 µmol/l phenylephrine to produce a maximal contraction, then field stimulation (FS), carbachol and nitroprusside were applied consecutively to determine relaxation effects. This procedure was repeated after strips were deprived of glucose and oxygen (in vitro ischemia) for 1 h. The following parameters were quantitated for all responses: maximal tension change; maximal and mean rates of tension change, and time to maximal response. Results: Effects of 1-hour in vitro ischemia on rabbit corporal tissue were as follows: (1) an 85% decrease in contractile response to phenylephrine, and (2) a marked increase in rate of contractile response to phenylephrine. Phenylephrine precontracted strips exhibited: (3) no change in relaxant response to FS; (4) increased relaxant responses to carbachol and nitroprusside; (5) no change in rates of relaxation in response to FS; (6) increased rates of relaxation in response to carbachol and nitroprusside, (7) no change in elapsed time to maximal relaxation in response to FS, and (8) decreased elapsed time to maximal relaxation in response to carbachol and nitroprusside. Conclusion: Digital analysis of the data generated facilitates recording, reviewing and analyzing of in vitro isometric tension studies on rabbit corpus cavernosum. Digital analysis allows quantification of additional parameters that have important implications for determination of mechanisms by which specific pathological processes occur.
Involvement of Nitric Oxide Synthase in Proteinuria Associated with Chronic Renal Disease in Rats
Authors: Brooks David P. , Contino Lisa C.
Published: April 2003

The present study demonstrates that the nitric oxide synthase inhibitor, aminoguanidine, can attenuate the proteinuria observed in a predominantly noninflammatory model of chronic renal disease in the rat. These data suggest that nitric oxide synthase may be involved in progressive renal disease.
Pedigree Analysis of a Subject with Abnormally Slow Renal Elimination of 6-Hydroxychlorzoxazone
Authors: Vesell Elliot S. , Korsunsky Zhanna
Published: April 2003

The family of an unusual subject was studied. When tested with chlorzoxazone (CX; 250 mg p.o.) on four separate occasions 5 years ago, this subject showed abnormally slow renal elimination of 6-hydroxychlorzoxazone (HCX), the primary CX metabolite. Since rates of CX biotransformation to HCX have served as a probe of the important cytochrome P450 isozyme, CYP 2E1, it was of interest that this unusual subject had normal conversion of CX to HCX. The present study revealed that over the past 5 years this subject accelerated his renal rate of HCX elimination which now lies at the slow end of the curve for normal subjects. His wife and 5 children all had more rapid rates than he for renal HCX elimination.
A Comparison of Spasmogenic and Relaxant Responses in Aortae from C57/BL/KsJ Diabetic Mice with Those from Their Non-Diabetic Litter Mates
Authors: Piercy V. , Taylor S.G.
Published: April 2003

We have investigated the responsiveness of thoracic aorta from the C57/BL/KsJ-db/db mouse (a model of type II diabetes) using a small-vessel myograph. The maximum tension developed in response to phenylephrine was greater in diabetic mice compared with non-diabetic (+/?) mice (2.7 ± 0.1 and 1.8 ± 0.1 mN/mm, respectively). Responses to phenylephrine were enhanced in tissues from both phenotypes when pre-incubated with L-NAME (100 µmol/l) and after the addition of oxyhaemoglobin (3 µmol/l), suggesting that endogenous NO release occurs in both. The maximum relaxation to carbachol was less in db/db mice (32 ± 4%) than in +/? mice (49 ± 5%) whilst that to sodium nitroprusside was similar (>90%). However, the concentration-effect curve to both vasorelaxants in db/db mice lay to the right of that in the +/? mice. These results suggest that the responsiveness of the vasculature is altered in the db/db mouse. Since this mouse is a model of type II diabetes this may be a consequence of hyperglycaemia and/or insulin resistance.
Respiratory Depression Produced by Intravenously Administered NBQX
Authors: McManigle John E. , Gillis Richard A. , Dretchen Kenneth L. , Taveira Da Silva Angelo M. , Hernandez Yvonne M.
Published: April 2003

To determine whether blockade of non-N-methyl-D-aspartate (non-NMDA) excitatory amino acid receptors affects breathing, we administered the non-NMDA receptor antagonist, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX), to anesthetized cats while monitoring phrenic nerve discharge, blood pressure and heart rate. NBQX, 3 and 10 mg/kg, i.v., reduced phrenic amplitude 59 ± 20% (n = 3) and 88 ± 6% (n = 5), respectively, and decreased respiratory rate. Phrenic activity was completely silenced in 3 animals. These effects were accompanied by decreased blood pressure and heart rate. Our data indicate that NBQX, a competitive antagonist of non-NMDA receptors, is a powerful depressant of cardiorespiratory activity.
Role of Cyclic Adenosine Monophosphate in Reducing Superoxide Anion Generation in Guinea Pig Alveolar Macrophages
Authors: Takei Katsumi , Tokuyama Kenichi , Kato Masahiko , Morikawa Akihiro
Published: April 2003

Alveolar macrophages (AM) may contribute to airway inflammation via release of superoxide anion (O–2). Elevation of intracellular cyclic adenosine monophosphate (cAMP) levels has been shown to suppress O–2 generation, although the exact mechanism is uncertain. To examine the inhibitory effect of cAMP against different stimuli for O–2 generation, we compared the effect of cAMP on O–2 generation caused by phorbol myristate acetate (PMA), a direct protein kinase C activator, and N-formyl-methionyl-leucyl-phenylalanine (FMLP), which couples its membrane receptor and stimulates guanosine triphosphate binding protein, in guinea pig AM. Cyclic nucleotide phosphodiesterase (PDE) isoenzyme inhibitors or CPT-cAMP, a cAMP analogue, were used in order to increase intracellular cAMP levels. The O–2 generation caused by either PMA or FMLP was reduced by cilostazol (PDE 3 inhibitor) and Ro20-1724 (PDE 4 inhibitor), but not by zaprinast (PDE 5 inhibitor). The degree of reduction in O–2 generation was not different between PMA and FMLP. Furthermore, CPT-cAMP also reduced PMA- or FMLP-induced O–2 generation to a similar degree, although only high concentrations (10–5 or 10–4 mol/l) of this agent were effective in producing significant inhibition. A remarkable elevation of the cAMP level is required to produce the inhibitory effect on O–2 generation in guinea pig AM. An elevation of cAMP may suppress O–2 generation by inhibiting plural sites of the intracellular signaling pathways.
Morphometric and Functional Changes of Rat Pituitary Somatotropes and Lactotropes after Central Administration of Somatostatin
Authors: Milošević Verica , Brkić Branislava , Velkovski S.D. , Sekulić Milka , Lovren Mirjana , Starčević Vesna , Severs W.B.
Published: April 2003

This study examined effects of intracerebroventricularly (i.c.v.) administered somatostatin (SRIH-14 and SRIH-28) on growth and function of pituitary somatotropes (GH cells) and lactotropes (PRL cells). Male rats received three i.c.v. injections (1 µg/5 µl) of SRIH-14 or SRIH-28 every second day. Blood samples were collected for hormone assays and pituitaries were removed for histological and morphometric evaluation 5 days after the last i.c.v. treatment. Compared to control animals, SRIH treatment decreased (p < 0.05) pituitary weight and all morphometric measurements obtained in GH and PRL cells. Concentrations of serum growth hormone (GH) and prolactin (PRL) in both SRIH-treated groups were also lower (p < 0.05) than in control rats. These findings suggest that centrally administered somatostatin is specifically involved in the control of growth and secretory activity of GH and PRL cells. Thus, pharmacological manipulation of SRIH receptors reached from cerebrospinal fluid may alter systemic effects of GH and PRL.
Bopindolol: A Slowly Dissociating Antagonist from the β-Adrenoceptors in Guinea Pig Atria
Authors: Hosohata Yoshiaki , Hattori Kaoru , Shen Yang , Okuyama Masahiro , Kaneko Hiroyuki , Ohnuki Toshio , Suzuki Jun , Nagatomo Takafumi
Published: April 2003

The dissociating and/or residual inhibitory effects of bopindolol from β-adrenoceptors of atria strips pretreated with this drug which was then washed out with buffers on the responses to isoprenaline were determined and compared with those of propranolol, pindolol, atenolol, and the two active metabolites of bopindolol: 18-502 and 20-785. Low concentrations of bopindolol (10–9 to 10–8 mol/l) and the active metabolite 18-502 (10–9 mol/l) produced rightward shifts of the concentration-response curves. On the other hand, high concentrations of bopindolol (10–7 mol/l) and metabolite 18-502 (10–8 and 10–7 mol/l) produced a reduced maximum response by isoprenaline, suggesting that these nonparallel rightward shifts have pD2 values of 7.57 (bopindolol) and 7.67 (18-502), respectively, at 0 min after washout with buffers. Pindolol (10–7 mol/l) and propranolol (10–7 and 10–8 mol/l) also produced a rightward shift of isoprenaline response curves, and these concentration-response curves in guinea pig atria strips pretreated with pindolol (10–7 mol/l) and propranolol (10–6 mol/l) recovered to control levels. Neither of these drugs, however, reduced the maximum response by isoprenaline. A high concentration (10–5 mol/l) of atenolol was required for a rightward shift of the isoprenaline concentration-response curve, and this drug also did not reduce the maximum response. Thus, we conclude that bopindolol and metabolite 18-502 slowly dissociate and act as noncompetitive β-antagonists rather than easily reversible β-adrenoceptor antagonists.
Vascular and Excretory Effects of Angiotensin II in the Rat Isolated Perfused Kidney: Influence of an AT1 and a NonselectiveAT Receptor Antagonist
Authors: Hilchey Sean , Quilley John , Bell-Quilley Caroline
Published: April 2003

Angiotensin II (AII) is a potent vasoconstrictor which, at physiological plasma concentrations, produces antinatriuresis, whereas high intrarenal concentrations cause natriuresis and diuresis. We examined the effects of a selective AT1 receptor antagonist, losartan, and a nonselective AT receptor antagonist, Sar1Thr8AII, on the response to infusion of AII in the isolated rat kidney perfused at constant pressure with a recirculating modified Krebs-Henseleit buffer. AII increased renal vascular resistance (RVR), glomerular filtration rate (GFR) and urinary volume (UV) and sodium excretion (UNaV) without changing the fractional excretion of water or electrolytes. Thus, changes in GFR can account for the natriuresis/diuresis. Both AII receptor antagonists prevented the increase in RVR. However, losartan was without effect on angiotensin-induced increases in GFR, UV or UNaV, whereas Sar1Thr8 AII also prevented the increases in GFR, UV and UNaV. The angiotensin receptor mediating the increase in GFR can be dissociated from that mediating the increase in RVR, providing functional evidence of angiotensin receptor subtypes in the rat kidney.
Thyroid Accumulation and Adverse Effects of Imipramine and Desipramine in Rats after Long-Term Administration
Authors: Rousseau Annick , Marquet Pierre , Lagorce Jean F. , Sauvage Marie F. , Buxeraud Jacques , Lachâtre Gérard , Raby Claude
Published: April 2003

The respective adverse effects of imipramine and desipramine on serum thyroid hormone levels and their accumulation in thyroid were investigated in male Wistar rats. Two groups of 30 rats were gavaged for 4 weeks with 30 mg/kg/day imipramine hydrochloride (IMI) or desipramine hydrochloride (DESI), while the control group (12 rats) received the arabic gum vehicle only. In the IMI-treated group, the serum thyroxine (T4) level significantly decreased (by 13%) and IMI and its metabolite DESI were accumulated in the thyroid, as pointed out by mean thyroid-to-serum concentration ratios close to 12 and 8, respectively. In the DESI-treated group, the mean thyroid-to-serum concentration ratio of the drug was close to 14, and significant decreases in both serum T4 (–20%) and triiodothyronine serum levels (–14%) were found. The accumulation of antidepressant drugs in the thyroid was more pronounced and the thyroid serum levels were even lower after DESI administration than after IMI administration. These results are in favour of an antithyroid action of IMI and DESI due to the formation of a complex in the thyroid between molecular iodine and the drugs or metabolites.
Study of Propranolol and Its Related Adrenoceptor Antagonists on Changes of Gastric Electrical Parameters Induced by Ethanol in Rats
Authors: Kaan Sheung K. , Cho Chi H.
Published: April 2003

The actions of different adrenoceptor antagonists on gastric potential difference (PD), electrical current (I) and resistance (R) were studied, using the voltage clamp technique. In an isolated gastric mucosal tissue, 5% ethanol was able to reduce the PD and I across the gastric mucosa. Direct incubation with propranolol 10–4 mol/l either from the mucosal or submucosal sides attenuated such effects. Intraperitoneal administration of propranolol (2.5–10 mg/kg), a nonselective β-adrenoceptor blocker with significant membrane-stabilizing activity, given 30 min before the preparation of the gastric tissue, not only alleviated the fall in PD and I across the gastric mucosa, but also increased the R of the stomach tissue. Butoxamine, a selective β2-antagonist, produced the similar but less significant effects in the same experimental setting. Metroprolol, a β1-adrenoceptor blocker, given by the similar doses did not produce significant effects. Nonselective β-adrenoceptor blocker, nadolol but not the β- and α-adrenoceptor blocker, labetalol, also significantly preserved the decrease of PD induced by ethanol, but to a lesser extent. These findings suggest that blockade of the β2-receptors in the gastric mucosa together with membrane-stabilizing activity could improve the integrity of the gastric mucosa, and these effects are probably acting through its direct action on the tissue.
Subacute Cocaine Treatment Changes Expression of Mouse Liver Cytochrome P450 Isoforms
Authors: Powers James F. , Shuster Louis
Published: April 2003

Acute administration of single high doses of cocaine (50 or 60 mg/kg) produces liver injury in mice that have been pretreated with inducers of mixed function oxidases. Multiple low doses of cocaine (10–30 mg/kg) will produce hepatotoxicity without prior induction. To establish whether cocaine can induce its own activation, mice were given three daily injections of cocaine. Total cytochrome P450 content of the liver did not change. After 3 days the amount of cytochrome P450 2B10, as measured by pentoxy resorufin-O-dealkylase activity and immunoblotting, increased 3-fold. Cytochrome P450 2A5-catalyzed coumarin 7-hydroxylase activity and immunoreactive protein increased by about 50%. Enzyme activities and Western blotting of isoforms 1A, 2E, and 3A showed no change during this time. Chronic cocaine increased N-hydroxylation of norcocaine. Immunoinhibition studies showed that cytochrome P450 2A5 was the major isoform responsible for norcocaine N-hydroxylation. These results demonstrate that chronic cocaine can induce its own metabolism. Similar increases were also observed in mice not susceptible to liver injury from chronic cocaine.
Effect of Am-80, a Synthetic Derivative of Retinoid, on Experimental Arthritis in Mice
Authors: Nagai Hiroichi , Matsuura Satoko , Bouda Keiko , Takaoka Yuko , Wang Ting , Niwa Satoru , Shudo Koichi
Published: April 2003

Am-80 is a newly snythesized retinoid with the structure of one aromatic amide among retinobenzoic acids. It exhibits specific biological activities of retinoic acid such as the activation of cellular differentiation and proliferation. We investigated the effect of Am-80 on collagen-induced arthritis (CIA) in mice and the immunopharmacological action on the production of several cytokines in the in vitro and in vivo models. Am-80, at doses of 0.3, 1 and 3 mg/kg, significantly inhibited the severity and development of the arthritis index, progression of foot pad swelling, bone damage and histopathological alterations. Am-80 also inhibited the production of anti-type II collagen (CII) IgG antibody, but did not affect the delayed-type hypersensitivity (DTH) response in arthritic mice. To determine the inhibitory mechanism of Am-80, we studied the effect of Am-80 on the production of cytokines. Am-80 did not affect the production of IFN-γ by Th1 cells (1E10.H2 cells) and IL-4 by Th2 cells (D10.G4.1 cells), respectively. Am-80 selectively inhibited bacterial lipopolysaccharide (LPS)-induced IL-6, but not TNF-α and IL-1β, production in mice. Moreover Am-80 inhibited IL-1β induced IL-6 production and IL-6 mRNA expression in human osteoblast-like cells (MG-63). The inhibition of IL-6 production by Am-80 was due to downregulation of the pretranscription or the transcription of IL-6 in MG 63 cells. These findings suggest that the inhibitory effect of Am-80 on CIA is partially by modulating the production of the proinflammatory cytokine, IL-6.
Effects of Losartan on the Sexual Behavior of Male Rats
Authors: Chan Paul , Liu Ju-Chi , Tong Yat-Ching , Chen Yi-Jen , Wang Chia-Chen , Tomlinson Brian , Cheng Juei-Tang
Published: April 2003

Many commonly used antihypertensive drugs such as diuretics and beta-blockers can interfere with sexual function in both sexes, causing loss of libido, impairment of erectile function and ejaculation in men, and delay or prevent orgasm in women. Newly developed antihypertensive drugs should ideally not interfere with the patients’ quality of life including sexual function. This study examined the effects of losartan, a nonpeptide, specific antagonist for type I angiotensin II receptors, on the male sexual behavior of rats. Spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats were treated with losartan 30 mg/ kg/day or saline control for 7, 30 and 90 days. Dark-cycle video recording was used to analyze the male sexual activities of the rats. No significant alteration in male sexual performance was observed after 7 and 30 days of treatment with losartan. In contrast, SHRs treated with propranolol 5 mg/kg/day showed increases in intromission latency, ejaculation latency and postejaculatory period indicating decreased libido and erectile and ejaculatory function. Upon completion of 90 days of losartan administration, the mount latency of the SHR was significantly increased, suggesting a decrease in libido although other parameters were unchanged and there was no effect in WKY rats. It is therefore concluded that losartan may have an advantage in preservation of sexual function when used clinically for the treatment of hypertensive disorders.
Inhibition of Calcium Influx during Hypoxia/Reoxygenation in Primary Cultured Rat Hepatocytes
Authors: Crenesse D. , Hugues M. , Ferre C. , Poiree J.C. , Benoliel J. , Dolisi C. , Gugenheim J.
Published: April 2003

Calcium has been demonstrated to play an important role in hepatocyte damage during ischemia/reperfusion phases. Calcium influx was determined in primary cultured rat hepatocytes submitted to a succession of warm hypoxia and reoxygenation phases in the presence of diltiazem, gallopamil and a Na+/H+ antiport inhibitor, HOE-694. Only diltiazem significantly inhibited calcium influx with higher potency after reoxygenation than after hypoxia only, suggesting a complex mechanism of action of diltiazem which could act on different physiological functions involved in Ca2+ invasion of hepatocytes after hypoxic insult.
Misoprostol-Inhibited Rat Gastric Emptying Is Independent of Gastric Inhibitory Polypeptide Release
Authors: Chang Full-Young , Chen Tseng-Shing , Lee Shou-Dong , Doong Ming-Luen , Wang PaulusS.
Published: April 2003

We studied the effects of orally or intraperitoneally administrated misoprostol on rat gastric emptying and looked what was the role of gastric inhibitory polypeptide (GIP) in this emptying. The rats initially received oral misoprostol at doses of 1, 10, 50, and 100 μg/kg. Another group of rats received misoprostol intraperitonally at doses of 10, 50, 250, and 500 μg/kg. Using an oral radiochromium motility marker, the liquid gastric emptying was measurement 30 min after misoprostol treatment. The plasma GIP levels were measured by a home-made radioimmunoassay kit. Oral treatments at the doses of 1 and 10 μg/kg did not influence emptying, whereas other doses delayed emptying (p < 0.01). Except the 10- μg/kg injection, other doses exhibited a dose-dependent inhibition in emptying (p < 0.01). Neither oral feeding nor intraperitoneal injection changed plasma GIP levels. We conclude that liquid gastric emptying is disturbed after various routes of misoprostol treatment; GIP appears less important in the misoprostol-mediated gastric emptying.
Histamine H2 Receptor Antagonism by T-593: Studies on cAMP Generation in Hepa Cells Expressing Histamine H2 Receptor
Authors: Tashiro Takao , Ono Kageyoshi , Watanabe Tsuyoshi , Inoie Masukazu , Arai Hirotoshi , Kimura Satoshi , Kurokawa Kiyoshi
Published: April 2003

Histamine H2 receptor antagonism by T-593 was investigated in Hepa cells expressing canine histamine H2 receptors. T-593 inhibited generation of cAMP in Hepa cells stimulated by 10–5 mol/l histamine with an IC50 value of 2.3 × 10–6 mol/l, (S)-(–)-T-593, one of the enantiomers comprising racemic T-593, inhibited cAMP generation with an IC50 value of 6.1 × 10–7 mol/l. On the other hand, the other enantiomer (R)-(+)-T-593 exhibited only a negligible effect. Incubation of the cell with (S)-(–)-T-593 for 60 min depressed the maximal response of the concentration-response curve of histamine with a nonparallel rightward shift. The slope of a Schild plot was 1.27. In contrast, (S)-(–)-T-593 caused a parallel rightward shift of the curve, with a Schild plot slope that did not significantly differ from unity, by treating the cells for 15 min. The H2 receptor-blocking action of (S)-(–)-T-593 remained almost unaffected after washing out the drug, whereas the effect of ranitidine was reversible after washing. These results suggest that T-593 possesses a time-dependent unsurmountable antagonistic action against histamine H2 receptor. T-593 may interact with the histamine H2 receptor molecule in a slowly associable and dissociable manner.
Enhancement by Arginine Vasopressinof the L-Type Ca2+ Current in Guinea PigVentricular Myocytes
Authors: Kurata Shuichi , Ishikawa Kazuo , Iijima Toshihiko
Published: April 2003

Effects of arginine-vasopressin (AVP) on the cardiac L-type Ca2+ current (ICa,L) were investigated in single ventricular cells of guinea pig hearts by the conventional and nystatin-perforated patch clamp methods. Using the conventional whole-cell clamp method, AVP (0.01–1 μmol/l) appeared to have little effect on ICa,L, but the same concentrations of AVP consistently increased ICa,L using the nystatin-perforated patch clamp mode. The stimulatory effect was blocked by either OPC-21268 (8 μmol/l), a selective V1 receptor antagonist, or staurosporine (10 nmol/l), an inhibitor of protein kinases. AVP further increased the amplitude of ICa,L previously augmented maximally by isoprenaline (1 μmol/l). When myocytes were pretreated with ryanodine (2 μmol/l) or cyclopiazonic acid (3 μmol/l), the increase in ICa,L by AVP was partially reduced. The present results indicate that protein kinase C might be involved in the AVP-induced increase of ICa,L. The AVP-induced increase in ICa,L may require intracellular constituents, which might be washed out during the use of the conventional whole-cell patch clamp method.
Effects of Green Tea Catechins on Membrane Fluidity
Authors: Tsuchiya Hironori
Published: April 2003

Catechins originating from green tea have been used in plaque inhibition for caries prevention and treatment for liver damage because of their antibacterial activity against cariogenic bacteria and protective activity on hepatic cells. The effects of catechins on membrane fluidity were studied by a fluorescence polarization method using liposomes prepared with dipalmitoylphosphatidylcholine and dioleoylphosphatidylcholine to assess their pharmacological mechanism at μmol/l levels found in human body fluids after clinical application. All eight catechins tested, ranging from 1 to 1,000 μmol/l, significantly reduced membrane fluidity in both hydrophilic and hydrophobic regions of lipid bilayers. Catechin gallate esters were superior in fluidity reduction to the corresponding nonesters. The fluidity-reducing degree was different between the cis and trans forms, suggesting the stereospecific activity of catechins. A reference antiplaque agent, chlorhexidine, similarly reduced membrane fluidity at the antibacterial concentration. (+)-Catechin (250 μmol/l) and (–)-epigallocatechin gallate (2.5 μmol/l) significantly prevented the membrane fluidization induced by hepatotoxic chloroform. These results indicate that the reduction in membrane fluidity is responsible for the antiplaque and hepatoprotective effects of green tea catechins.