Enhanced monoamine release in the median preoptic area following reduced extracellular fluid volume in rats

The role of monoaminergic neural inputs to fluid regulatory systems in the median preoptic nucleus (MnPO) was investigated by examination of monoamine metabolism during reduction of systemic extracellular fluid volume in freely moving rats. Extracellular fluid volume was decreased iso-osmotically by subcutaneous polyethylene glycol (PEG), and extracellular noradrenaline (NA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) were measured using intracerebral microdialysis techniques. PEG treatments significantly increased NA, DA and DOPAC release in the MnPO area. The results suggest that monoaminergic neural systems in the region of the MnPO are important in the control of extracellular fluid balance.

Inhibition by a novel azole antifungal agent with a geranyl group on lanosterol 14 alpha-demethylase of yeast

AFK-108 (1-[2-(2,4-dichlorophenyl)-2-((2E)-3,7-dimethylocta-2,6- dienyloxy)ethyl]-1H-imidazole) is a new imidazole derivative characterized by a geranyl substituent showing strong antifungal activity. Azole antifungal agents are known to be potent inhibitors of lanosterol 14 alpha-demethylase (P450(14)DM) of fungi. The role of the geranyl group of AFK-108 on interaction of AFK-108 with the target was studied by using Saccharomyces cerevisiae P450(14)DM as the model enzyme. AFK-108 and some of its derivatives bound to oxidized P450(14)DM with one-to-one stoichiometry and inhibited the demethylase activity. AFK-108 derivatives having the longer farnesyl or the shorter prenyl group showed lower affinity than AFK-108 for the enzyme. AFK-108 caused 100% inhibition at the equivalent concentration to P450(14)DM in the reaction mixture (0.07 microM), while the farnesyl derivative inhibited the activity by 60% at the same concentration. AFK-108 interfered with the binding of CO to the ferrous P450(14)DM. However, the interfering effect of the prenyl derivative was lower than that of AFK-108. Another AFK-108 derivative having the saturated 3,7-dimethyloctyl group was also a weaker inhibitor than AFK-108. These experiments suggest that the geranyl group of AFK-108 interacts with the substrate binding site of P450(14)DM that recognises the side chain of the substrate. AFK-108 is the first example of an azole derivative interacting with the side chain recognising region of the substrate binding site of P450(14)DM.

Gene structure and multiple mRNA species of Drosophila melanogaster aldolase generating three isozymes with different enzymatic properties

Genomic clones encoding the Drosophila aldolase gene were isolated and the organization of the gene was determined. The protein-coding region spanning nearly 3.5 kb consists of five coding exons (exon 2, 3, 4 alpha, 4 beta, and 4 gamma). The insect exon 2 corresponds to exons 2 to 7 of vertebrate aldolase genes and thus appears to have been formed by the fusion of these 6 exons into a single exon during evolution. The Drosophila aldolase gene is predicted to generate mRNAs for three isozymes (alpha-, beta-, and gamma-types) from the primary transcripts by alternative usage of the final three exons. The reverse transcriptase-PCR assay revealed the occurrence of mRNAs for the three isozymic forms at different developmental stages, and tissue-specific expression was also found to occur in adult flies. In addition to the usual type mRNA species for the alpha-, beta-, and gamma-isozymes, two novel forms of mRNAs, alpha beta- and beta gamma-type mRNAs, were detected tissue-specifically in adult flies, although their functions are unpredictable. The alpha beta-mRNA is an alpha-type mRNA in which exon 4 beta remains unspliced, while the beta gamma-mRNA is a beta-type mRNA with the exon 4 gamma remaining unspliced. Recombinant enzymes expressed in Escherichia coli were all active and exhibited different enzymatic properties.

Inhibition of ionotropic neurotransmitter receptors by antagonists: strategy to estimate the association and the dissociation rate constant of antagonists with very strong affinity to the receptors

Since binding of an agonist to an ionotropic neurotransmitter receptor causes not only channel opening, but also desensitization of the receptor, inhibition of the receptor by the antagonist sometimes becomes very complicated. The transient state kinetics of ligand association and dissociation, and desensitization of the receptor were considered on the basis of the minimal model proposed by Hess' group, and the following possibilities were proposed. 1) When an agonist is simultaneously applied to the receptor with an antagonist whose affinity to the receptor is extremely strong and different from that of the agonist, it is usually impossible to estimate the real inhibition constant exactly from the responses because desensitization of the receptor proceeds before the equilibrium of the ligand binding. Simultaneous addition of the antagonist with strong affinity to the receptor may apparently accelerate inactivation (desensitization) of the receptor. The association rate constant of the antagonist can be estimated by analyses of the rate of the inactivation in the presence and the absence of the antagonist. 2) A preincubated antagonist with a slow dissociation rate constant, i.e., a very effective inhibitor, may cause apparent noncompetitive inhibition of the receptor, since the receptor is desensitized by an agonist as soon as the antagonist dissociates from the receptor and the dissociation of the antagonist from the receptor becomes the rate-determining step. A nicotinic acetylcholine receptor (nAChR) was expressed in Xenopus oocytes by injecting mRNA prepared from Electrophorus electricus electroplax and used for the experiments on inhibition by an antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased monoamine turnover in the subfornical organ area following body fluid depletion

To clarify whether monoaminergic inputs to the subfornical organ (SFO) area participate in fluid regulatory systems, we examined the effects of body fluid depletion on monoamine turnover in the region of the SFO using microdialysis techniques in rats. An iso-osmotic reduction of fluid volume following subcutaneous treatment with polyethylene glycol (PEG) significantly increased dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the SFO area. 5-hydroxytryptamine (5-HT) in the SFO area could be detected after the PEG treatment, while 5-HT was undetectable before the treatment. The data imply that both dopaminergic and serotonergic systems in the SFO area may be involved in controlling body fluid balance.

Mechanisms for appearance of no-flow areas in tumor microvascular bed

In order to elucidate the mechanism for appearance of no-flow areas (areas where tumor blood flow temporarily cease), we directly observed the process of tumor-induced neovascularization and measured pressure change in a feeding vessel (starting vessel) which supplies blood to the tumor vascular network. Total length of tumor vascular network from one starting vessel increased exponentially as the tumor increased in size exponentially. The pressure of the starting vessel increased from approximately 40 cmH2O to 120 cmH2O with enlargement of the tumor size. As soon as the pressure of the starting vessel reached a plateau, however, there was a rapid increase in low-flow or no-flow areas in places within the tumor. We considered that no-flow areas were produced by the imbalance between the pressure elevation of a starting vessel and the enlargement of the vascular network from that vessel.

Segmental asynergy of the left ventricle in a case of tight aortic stenosis associated with mild ischemic heart disease

Emergency aortic valve replacement with double aorto-coronary bypass surgery was performed to treat severe intractable congestive heart failure in an 82-year-old man. Mild circumflex and left anterior descending artery lesions were present and the pressure gradient across the aortic valve was 80 mmHg despite a low cardiac output. The preoperative anteroseptal akinesia seen by two-dimensional echocardiography was normalized after surgery. Thus, even in patients with segmental left ventricular dysfunction, tight aortic stenosis might be present when concomitant mild ischemic heart disease is present.

Altered structure and expression of the p53 gene in human neuroepithelial tumors

The p53 gene, located on chromosome 17p13.1, may be important in the pathogenesis of human neuroepithelial tumors, because it is a tumor suppressor gene and genetic alteration is essential for certain human cells to acquire the neoplastic phenotype. The structure and expression of the p53 gene were investigated in cultured human glioma cells and biopsied specimens of neuroepithelial tumors. Immunocytochemical examination of p53 gene expression revealed positive nuclear staining in six of seven glioma cell lines tested. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis demonstrated unequivocal heterogeneity of migration rate in p53 bands. Pulse-chase analysis clearly showed an increased half-life of p53 in cultured human glioma cells. These abnormalities are presumably due to genetic alterations in the p53 gene. Nucleotide substitutions in exon 5, 7, or 8 of the p53 gene could be detected by polymerase chain reaction-single strand conformational polymorphic analysis in four of seven (57%) human glioma cell lines, and nine of 29 (31%) biopsied specimens of neuroepithelial tumors examined. The present results indicate that genetic alterations in the p53 gene are responsible for the tumorigenesis of at least some human neuroepithelial tumors.

Actin-actin contact: inhibition of actin-polymerization by subdomain 4 peptide fragments

F-Actin was digested with alpha-chymotrypsin in 6 M urea, and two peptide fragments from subdomain 4 of actin molecule [Kabsch, W., Mannherz, H.G., Suck, D., Pai, E.F., & Holmes K.C. (1990) Nature 347, 37-44] were purified by reverse-phase HPLC and Sephadex G-50 gel filtration. The peptide fragments were identified as segments from Arg-177 to Tyr-198 (2.6-kDa peptide) and from Ser-199 to Tyr-279 (9.1-kDa peptide). Their effects on actin polymerization induced by 50 or 100 mM KCl were studied by measuring the increase in viscosity by the falling ball method. The 2.6-kDa peptide decreased the rate of actin polymerization and increased the critical concentration for the polymerization. Based on the atomic model of the actin filament [Holmes, K.C., Popp, D., Gebhard, W., & Kabsch, W. (1990) Nature 347, 44-49], the peptide is presumed to bind to the barbed end of the actin filament and inhibit the polymerization. By assuming that the peptide affected the rate of association of the actin monomer to the end of the actin filament, well-fitting curves for the polymerization kinetics were calculated. Computer-assisted results indicated that the dissociation constant of the 2.6-kDa peptide for F-actin is 200 to 260 microM. In contrast, the 9.1-kDa peptide only slightly inhibited actin polymerization. These results suggest that the actin-actin interface in the region between Arg-177 and Tyr-198 has a stronger interaction than those between Ser-199 and Tyr-279. The amino acid sequence L-T-D-Y-L present in the 2.6-kDa segment is homologous to a common sequence in the F-actin capping domain of various actin-binding proteins.

In vivo study of flow pattern at human carotid bifurcation with regard to aneurysm development

In order to investigate the developmental mechanism of cerebral aneurysms, the in vivo flow pattern around human cervical carotid bifurcations was studied by flow visualization using digital subtraction angiography with an isotonic contrast medium. The blood stream containing the medium impinged on the apex, then proceeded along the walls of the branches. After opacification of the whole lumen around the apex, most of the medium was carried away, while some remained for a few seconds at the carotid sinus. In the internal carotid artery, the blood struck the wall at an oblique angle near the tops of the arterial curvatures. In cases with atheromatous plaque or kinking of the branch, the blood passed through the stenosed segment and moved upstream, indicating turbulence. The study suggests that haemodynamic forces around the apex consist mainly of impingement on the apex and shear stress to the wall at and around the apex. In branches, high shear stress seems to exist. It might be possible that high shear stress causes degenerative changes in the endothelial layer, initiating the formation of saccular and fusiform cerebral aneurysms.

Indonesian medicinal plants. II. Chemical structures of Pongapinones A and B, two new phenylpropanoids from the bark of Pongamia pinnata (Papilionaceae)

Two new phenylpropanoids named pongapinone A (1) and pongapinone B (2) were isolated from the bark of Pongamia pinnata (Papilionaceae), an Indonesian medicinal plant, and their chemical structures have been elucidated on the basis of their physicochemical properties. Pongapinone A (1) was found to inhibit interleukin-1 production.

Effects of dihydroergotoxine on central cholinergic neuronal systems and discrimination learning test in aged rats

We evaluated changes in the cholinergic neuronal system and learning ability with aging. Choline acetyltransferase (ChAT) activity, a presynaptic index of the cholinergic system, was decreased in the cerebral cortex, hippocampus, striatum, and hypothalamus in the brain of aged rats compared with young adults. Muscarinic cholinergic binding sites (receptors, MCR), a postsynaptic index of the cholinergic system, were markedly decreased in all areas of the brain. However, intraperitoneal injection of 1 mg/kg of dihydroergotoxine (DHET) for 14 days normalized both ChAT and MCR in the cerebral cortex and hippocampus. In the striatum, ChAT was normalized, but MCR did not recover. Aged rats showed marked learning impairment in a 30-day operant type brightness discrimination learning test. Daily DHET administration restored the discrimination ability in the aged rats to nearly the young adult level. DHET had no effects on central cholinergic indices or learning test results in young adult rats. These findings suggest that learning is impaired in aged rats due to impairment in the central cholinergic neuronal system, and that DHET normalizes the decreased function in this system, restoring the learning ability.

Systemic and cutaneous plasmacytosis with multiple skin lesions and polyclonal hypergammaglobulinaemia: significant serum interleukin-6 levels

We report two patients who developed benign plasmacytosis with multiple skin lesions. The cases were characterized by hyperplasia of mature plasma cells, and polyclonal hypergammaglobulinaemia. One patient had hyperplasia of mature plasma cells not only in the skin, but also extensively in lymph nodes and the retroperitoneal areas around the ureters. The other had plasma cell hyperplasia limited to the skin. Extensive investigations failed to reveal any clinical or laboratory evidence suggesting the presence of any underlying disease accompanying the hypergammaglobulinaemia and/or plasma cell proliferation, such as chronic infectious disease, collagen disease or other chronic inflammatory disorder. Clinically and histologically, the first patient showed features compatible with a diagnosis of systemic plasmacytosis and the second with a diagnosis of cutaneous plasmacytosis. Significant serum interleukin-6 (IL-6) levels were detected in both patients, suggesting that IL-6 may be involved in the pathogenesis of these conditions.

Progression of Takayasu's aortitis in a young japanese woman: Serial angiographic study

Progression of Takayasu's aortitis was observed by serial angiography over 2 years. Acute aortic regurgitation due to marked dilatation of the proximal ascending aorta was followed by aneurysmal dilatation of the distal ascending aorta. Aneurysmal dilatation of the carotid arteries then developed, with subsequent obstruction of both the bilateral vessels by thrombosis.

Deep negative T waves associated with reversible left ventricular dysfunction in acute adrenal crisis

We report two cases of reversible left ventricular dysfunction associated with deep negative T waves during acute adrenal crisis due to isolated deficiency of adrenocorticotrophic hormone. There were no symptoms suggestive of heart disease in either case and left ventricular wall motion abnormalities, present mainly around the left ventricular apex, returned to normal in 1-2 weeks. Deep negative T waves normalized 4 weeks after corticosteroid administration. Acute adrenal crisis should be considered when deep negative T waves are associated with left ventricular dysfunction without cardiac symptoms.

Distribution of 5'-nucleotidase in muscle of some marine fishes

A preliminary examination for the purification and characterization of 5'-nucleotidase of fish muscle was carried out and the following results were obtained. 1. The activities of 5'-nucleotidase in the muscles of marine vertebrates and invertebrates (total 11 species) were determined. The highest activity of 5'-nucleotidase was found in Blackrock fish Sebastes inermis, which was then used as a material for estimation of subcellular distribution and solubilization of the enzyme. 2. The 5'-nucleotidase of ordinary muscle of the fish Sebastes inermis was found in nuclear, microsomal and cytosolic fractions. About half of the total activity was found in the nuclear fraction, whereas the highest specific activity was observed in the microsomal fraction. 3. Complete solubilization of the enzyme was attained by using a high concentration of detergent such as Triton X-100, CHAPS, octylglucoside, octylthioglucoside and sodium deoxycholate, suggesting that the enzyme was tightly bound to the membrane. 4. Based on the results of solubility and stability tests, Triton X-100 seemed suitable for solubilizing 5'-nucleotidase from the membrane. 5. Microsomal 5'-nucleotidase was an Mg(2+)-activated enzyme, and no inactivation was observed up to 50 mM of Mg2+.

Isolation and sequence of a developmentally regulated putative novel gene, priA, from the basidiomycete Lentinus edodes

Screening for gene(s) homologous to v-Ha-ras (Harvey rat sarcoma viral ras gene) in the basidiomycete, Lentinus edodes, resulted in the isolation of a novel gene (designated priA), in addition to a ras gene homologue [Hori et al., Gene 105 (1991) 91-96]. The priA gene has a coding capacity of 258 amino acids (aa) interrupted by two short putative introns. The 5'-upstream region of priA contains GGGCGG box, CCAAT box, TATAAA box and CT sequence elements in 5'----3' order. One transcription start point (tsp) was located 10 nucleotides upstream from a TATAAA box and another tsp just in a CT sequence. The deduced PRIA protein (26.7 kDa), rich in Ser (42 residues), Pro (29 residues) and Thr (27 residues), contained different types of putative zinc-binding motifs. It initiated with a hydrophobic aa sequence and terminated with the unique sequence, Cys-Aaa-Aaa-Xaa (where Aaa is aliphatic aa and Xaa is any aa), implying an association with the inner membrane surface via acylation of the Cys residue. The priA gene expression was found to be developmentally regulated with primordia/immature fruiting bodies having much higher levels of priA transcript. Preprimordial mycelia and mature fruiting bodies, however, contain very low levels of priA transcript. The priA gene may play a role during the beginning of fruiting.

Suppression of anchorage-independent growth of human glioblastoma cell by major histocompatibility complex class I gene-transfection

The host's immune system discriminates tumor cells from normal cells by recognizing the major histocompatibility complex (MHC) class I antigen expressed on the tumor cell membrane. However, the role of MHC class I antigen in tumor cells has not yet been clarified. In this study, the influence of MHC class I antigen expression on the tumorigenicity of a human glioblastoma cell line (KMG4) is examined. Barely detectable levels of MHC class I messenger ribonucleic acid were found to express in KMG4 cells by Northern blot analysis using mouse MHC class I (H-2Ld) and human leukocyte antigen (HLA)-B7 genes as probes. The H-2Ld gene connected at the downstream end of murine mammary tumor virus (MMTV)-promoter was cotransfected with the neomycine-resistant gene pSV2-neo into KMG4 cells, and the drug-resistant cells were selected. The KMG4 cells (KMG4-MMTV-Ld), which acquired the MHC class I gene were detected by Northern blot analysis with H-2Ld as the probe, and by immunohistochemistry using the H-2Ld-specific monoclonal antibody. Tumorigenicity, as determined by colony-forming ability in soft agar, was then compared between MHC class I-expressing KMG4-MMTV-Ld and nonexpressing control cells. The MHC class I-expressing cells were found to be deprived of colony-forming ability, indicating that MHC class I antigen could negatively influence the anchorage-independent cell growth of the human glioblastoma cell line KMG4.

Circadian variation of tumor blood flow in rat subcutaneous tumors and its alteration by angiotensin II-induced hypertension

Circadian fluctuation in tumor blood flow of the rat subcutaneous tumor was investigated. Tumor tissue blood flows in the daytime zone (10 a.m. to 4 p.m.) and in the nighttime zone (10 p.m. to 4 a.m.) in both the first phase (doubling time of tumor volume = 1.7 days) and the second phase (doubling time of tumor volume = 5.7 days) of growth of the LY80 tumor in rats were measured using the hydrogen gas clearance technique. In the first phase of tumor growth, the tumor blood flow was 20.3 +/- 12.2 ml/min/100 g in the daytime zone (n = 22) and 46.6 +/- 19.3 ml/min/100 g in the nighttime zone (n = 22). In the second phase, tumor blood flow was 9.6 +/- 5.7 ml/min/100 g in the daytime zone (n = 45) and 19.4 +/- 8.2 ml/min/100 g in the nighttime zone (n = 38). Tumor blood flow in the nighttime zone was significantly higher than that in the daytime zone (first phase, P less than 0.001; second phase, P less than 0.001). However, there were no significant differences in the mean arterial blood pressure, tumor size, and body weight of rats between the daytime zone and the nighttime zone. There was also a marked difference in the effect of angiotensin II-induced hypertension on tumor blood flow between the daytime zone and the nighttime zone. These results suggest that circadian fluctuations in tumor blood flow should be carefully considered when developing strategies to maximize the effectiveness of cancer therapy in relation to the flow rate of circulating blood.

Cytokeratin Polypeptide Profile of Merkel Cells in Human Fetal and Adult Skin: Difference of Expression of Cytokeratins in Epidermal and Dermal Merkel Cells

The origin of Merkel cells is uncertain, although current evidence by immunohistochemical keratin marker studies favors an epidermal derivation. We studied the expression of keratin species in Merkel cells of human fetus and adult using 19 anti-keratin antibodies. Epidermal and dermal Merkel cells contained not only simple epithelium-type but also some stratified epithelium-type keratins. Interestingly, expression of some keratins was different between epidermal and dermal Merkel cells, for example, AN3 (50, 58 kD) and CKB1 (50 kD) recognized epidermal Merkel cells, but not dermal Merkel cells. These results suggest that surrounding keratinocytes influence the expression of cytokeratins in Merkel cells or that dermal Merkel cells undergo a modification from keratin-producing epidermal Merkel cells to a more neural cell type by the association with nerve endings in the upper dermis. On the other hand, certain cytokeratin polypeptides recognizable with Ks19.1 (40 kD), CK5 (45 kD), and CAM5.2 (52.5 kD) were expressed in both epidermal and dermal Merkel cells. The expression of simple epithelium-type keratins in Merkel cells remained even after the epidermal basal cells gradually lost their expression.

Continuous murmur in Lutembacher syndrome analyzed by Doppler echocardiography

A continuous murmur was heard in a 47-year-old woman with Lutembacher syndrome. Transesophageal and intraoperative Doppler echocardiography revealed the murmur originating from the accelerated blood flow passing through the small atrial septal defect. To our knowledge, this is the first reported case of a continuous murmur in Lutembacher syndrome analyzed by Doppler echocardiography.

[Postoperative infection control in patients with hepatic, biliary tract, and pancreatic cancers]

Postoperative infection occurs more frequently in patients with malignant disease than in patients with benign disease. Postoperative infection control in patients with hepatic cancer, biliary tract cancer and pancreatic cancer is studied. Although in patients with jaundice due to malignancy the rate of positive bacterial culture of the bile collected at the time of PTCD was low, the rate of positive bile culture increased after 10 to 14 days of PTCD. The predominant strain was Enterococcus spp., followed by Klebsiella spp., Enterobacter spp. and E. coli in that order. These bacteria isolated from the bile were considered to be causative organisms of postoperative infection. Prophylactic antibiotics after the operation for jaundice due to malignancy should be chosen based on the results of bile culture. In patients undergoing hepatectomy, which is considered to be an aseptic operation, gram positive cocci such as S. aureus was the most frequently encountered organism. On the other hand, in patients undergoing hepatectomy and intestinal anastomosis, enteric bacteria were frequently isolated from the infectious foci. In this study there were 6 cases of methicillin-resistant S. aureus (MRSA) postoperative infection, 3 cases after pancreatoduodenectomy, and 3 cases after hepatectomy. Even after an aseptic operation, postoperative MRSA infection is likely to occur in patients undergoing a more invasive operation, so hospital infection control should be again emphasized.