Synthesis and pharmacological evaluation of isoindolo[1,2-b]quinazolinone and isoindolo[2,1-a]benzimidazole derivatives related to the antitumor agent batracylin

The synthesis and pharmacological activity of isoindolo[1,2-b]quinazolin-12(10H)-ones and isoindolo[2,1-a]benzimidazoles related to batracylin are described. The acute toxicity of batracyclin has been associated with the formation of its N-acetyl metabolite which is a potent inducer of unscheduled DNA synthesis in rat hepatocytes. The desamino derivative and the 8-aza analog of batracylin retained the ability to inhibit topoisomerase II but did not induce unscheduled DNA synthesis. While less active than batracylin, these analogs were cytotoxic to CCRF CEM leukemia cells. The isoindolo[2,1-a]benzimidazole derivatives were inactive as topoisomerase II inhibitors and, in general, failed to exhibit comparable antitumor activity or to induce unscheduled DNA synthesis.

Use of (CA)n polymorphisms to determine the origin of blood cells after allogeneic canine marrow grafting

We have used a polymerase chain reaction-based assay measuring polymorphic (CA)n repeats, a class of simple sequence repeats, to assess the success of allogeneic canine marrow transplants. Results were compared with those obtained with karyotype analysis of dividing cells in recipients that were sex mismatched with their marrow donors. Twenty recipients were conditioned for transplantation of genotypically DLA-identical littermate marrow by 450 cGy of total-body irradiation. In 2 recipients, results could not be compared, since either only cytogenetic or dinucleotide (CA)n marker data existed. Both dogs had autologous marrow recovery. In 15 of the remaining 18 recipients, complete agreement was found between the results obtained with dinucleotide (CA)n markers, cytogenetic studies, and granulocyte changes after transplantation. Seven of the 15 showed eventual autologous recovery, 6 displayed mixtures of host and donor cells, and 2 showed donor-type hematopoiesis. Two of the 18 dogs showed mixed chimerism with (CA)n markers and autologous recovery by cytogenetics, findings that may be related to differences in cells analyzed by the two techniques--i.e., all nucleated cells by (CA)n markers versus dividing cells by cytogenetics. In one additional recipient, results of marrow cytogenetics, granulocyte changes, and (CA)n markers were consistent with a successful allograft, while peripheral blood cytogenetics suggested autologous recovery, possibly the result of erroneous blood sampling. Polymerase chain reaction-based testing for dinucleotide repeat (CA)n polymorphisms, originally developed for genetic mapping in the dog, is useful and reliable when compared with cytogenetic studies, in assessing the success of allogeneic marrow transplants in dogs.

Cardiotoxin II from Taiwan cobra venom, Naja naja atra. Structure in solution and comparison among homologous cardiotoxins

The three-dimensional structure in solution of cardiotoxin II, a membrane toxin from the venom of Taiwan cobra, Naja naja atra, was determined using 1H nuclear magnetic resonance spectroscopy and molecular modeling based on the hybrid distance geometry/dynamic simulated annealing technique. A complete sequence-specific proton assignment was obtained, and the secondary structures of the protein were determined from information on nuclear Overhauser effect connectivities, coupling constants, and hydrogen exchange were confirmed using the main-chain-directed strategy. Twelve simulated annealing structures found to be within a single family were selected based on the condition of distance constraint violation less than 0.02 nm and the dihedral angle violation less than 4 degrees. The average atomic root mean square deviation between the selected structures and their geometric average are 0.079 nm for the backbone atoms and 0.137 nm for all heavy atoms; they are 0.044 nm and 0.117 nm, respectively, when considering the secondary structural residues only. The molecule adopts a compact structure consisting of three major loops emerging from a globular head. These loops contain five strands to form double- and a triple-stranded antiparallel beta sheets. Comparisons are made between this structure and those of its homologous cardiotoxins in order to derive further information on their structural variations.

Characteristics of acupuncture meridians and acupoints in animals

In recent years, an increasing number of studies has been conducted on the biophysical characteristics of the meridians and acupoints in humans and animals. The authors aim to further illustrate the objective existence and superficial locations of the meridians in various species of animals. Twelve sheep, ten goats, thirteen pigs, eleven cats, eight rabbits and seven donkeys were used to measure low impedance lines (LILs) and high percussion sound lines (HPSLs) on the skin surface of the animals, along the vertical planes of the dorsal line, using electrical impulses and high percussion sound. The results of these studies are given.

Antineoplastic activity of benzimidazo[1,2-b]-isoquinolines, indolo[2,3-b]quinolines, and pyridocarbazoles

Substituted pyrido[3,4-b]carbazoles, pyrido[2,3-b]carbazoles, indolo[2,3-b]quinolines, and benzimidazo[1,2-b]-isoquinolines were synthesized and evaluated for biological activity. Several methylated derivatives of these heterocyclic compounds had similar activity to ellipticine as mammalian topoisomerase II inhibitors. Methylated derivatives of these heterocyclic compounds were also highly active in vitro, inhibiting the growth of several human tumor cell lines. These data demonstrate that the antineoplastic activity associated with ellipticine can be retained within a wide variety of analogous heterocyclics.

Solution conformation of enopeptin A, a depsipeptide antibiotic, using 2D NMR and restrained molecular dynamics studies

Studies on the solution conformation of the cyclic depsipeptide antibiotic enopeptin A have been carried out using 2D NMR and molecular modelling techniques. The proton resonances of the antibiotic in DMSO-d6 have been assigned by the use of TOCSY and ROESY experiments. The interproton distance information obtained from the ROESY experiments have been used as the basis for elucidating the probable structures in solution. The restrained molecular dynamics technique was applied to calculate the structures in solution, and six resultant structures with fewer distance constraint violations were obtained that satisfy the experimental restraints very well. The conformation of the cyclic moiety of the molecules is well defined whereas the aliphatic chain segment is disordered.

Microvessel count and cerebrospinal fluid basic fibroblast growth factor in children with brain tumours

Tumour growth is angiogenesis-dependent; brain tumours have more intense neovascularisation than other tumours and produce basic fibroblast growth factor, a potent angiogenic mediator. Because little is known about the release of basic fibroblast growth factor from brain tumours into extracellular fluids, we tested cerebrospinal fluid (CSF) from 26 children and young adults with brain tumours and 18 controls for basic fibroblast growth factor and for proliferative activity on cultured capillary endothelial cells. We also measured the density of microvessels in tumours by immunohistochemical staining. Basic fibroblast growth factor was detected in the CSF of 62% (16 of 26) patients with brain tumours but in none of the controls. Specimens with basic fibroblast growth factor stimulated DNA synthesis of capillary endothelial cells in vitro. Endothelial proliferative activity was blocked by neutralising antibodies to basic fibroblast growth factor. Basic fibroblast growth factor correlated with mitogenic activity in CSF in vitro (p < or = 0.0001), and with density of microvessels in histological sections (p < or = 0.005). A microvessel count of > or = 68 per 200 x field was associated with tumour recurrence (p = 0.005) and with mortality (p = 0.02). Basic fibroblast growth factor in brain tumours may mediate angiogenesis as measured by microvessel density in histological sections, so has potential as both a marker for neoplasia and a target for tumour treatments. Furthermore, evaluation of cerebrospinal fluid basic fibroblast growth factor, along with microvessel quantitation in biopsied tumours, may provide improved prognostic information for the management of patients with brain tumours.

Understanding patterns of immunoglobulin gene rearrangements

When immunoglobulin (Ig) gene rearrangements are analyzed, several patterns emerge. The rearrangements at the various loci generally appear in a specific temporal order. In addition, within a given locus the frequency of rearrangement of the various gene segments is not equal but is skewed towards preferential rearrangement of particular gene segments. Understanding the reasons for these patterns will shed light on the mechanism of recombination, the regulation of rearrangement, and the relationship between Ig gene rearrangement and B cell development. In this review, we discuss evidence that the observed patterns of Ig gene rearrangement are due to a combination of factors including the recombination signal sequences, sequences in the coding termini, the accessibility of genetic elements to V(D)J recombinase, and cellular selection.

An algorithm and computer program for calculating the mean transit time and distribution rate parameters of generated metabolites undergoing linear tissue distribution and linear or non-linear central elimination

A method is described for calculating the mean transit time and distribution rate parameters of a generated primary metabolite undergoing linear distribution and linear or non-linear central elimination, and of catenary metabolites with any precursor order. It is also applicable to a drug and its interconversion metabolite and does not require separate administration of the metabolite. The method allows steady-state volume of distribution and distribution clearance of a metabolite to be calculated, provided that the central volume of distribution of the metabolite is known. An algorithm and computer program to implement the proposed method are presented. The calculations require the plasma concentration versus time curves of the metabolite and its precursor. The method is applied to both published and simulated data.

Synovial interleukin-1 receptor antagonist and interleukin-1 balance in rheumatoid arthritis

OBJECTIVE

To quantify interleukin-1 receptor antagonist (IL-1ra) and IL-1 production and gene expression by rheumatoid arthritis (RA) synovial tissue (ST) cells.

METHODS

IL-1 alpha, IL-1 beta, and IL-1ra protein levels were measured by enzyme-linked immunosorbent assay in fresh and cultured ST cells, purified synovial macrophages, and fibroblast-like synoviocytes (FLS). The relative expression of the secreted form of IL-1ra (sIL-1ra) and the alternatively spliced intracellular form (icIL-1ra) was determined by reverse transcription polymerase chain reaction (RT-PCR) techniques.

RESULTS

IL-1 alpha, IL-1 beta, and IL-1ra were present in fresh and cultured ST cell samples of synovium from RA and osteoarthritis patients. IL-1ra:IL-1 ratios ranged from 1.2 to 3.6, which is below the 10-100-fold excess of IL-1ra needed to inhibit IL-1 bioactivity. Isolated CD14+ synovial macrophages secreted IL-1ra, but the amount was much less than that of alveolar or in vitro-derived macrophages. Cultured FLS contained intracellular IL-1ra but secreted little IL-1ra into the culture supernatants. RT-PCR showed that icIL-1ra mRNA was more abundant than sIL-1ra mRNA in FLS and unfractionated ST cells.

CONCLUSION

IL-1ra production by RA ST cells is deficient relative to total production of IL-1.

[Studies on the detection of Legionella pneumophila by the application of polymerase chain reaction (PCR)]

DNA fragment of Legionella pneumophila, the PCR was performed with a pair of artificial synthesized primer. Results of agarose electrophoresis and EB staining showed that there was a 870 bp band shared by serogroups 1-14 of L.pneumophila. The sensitivity of PCR in detecting Legionella from water was 350cfu/ml, however, the specific DNA probe labeled with 32P was .43cfu/ml by blot hybridization. The positive rate of tissue specimens from infected guinea-pigs with Legionella pneumophila was 83.3% by PCR detection, and only 26.6% by bacteriological culture method. An outbeak caused by Lp10 was verified by PCR. The result showed that the PCR could detect the infection of Legionella rapidly, specifically and sensitively.

NMR spectra and restrained molecular dynamics of the mushroom toxin viroisin

The conformation of viroisin, the monocyclic toxic heptapeptide of the virotoxin family from mushroom Amanita virosa, was analysed using two-dimensional nuclear magnetic resonance spectroscopy and restrained molecular dynamics simulations. All proton signals were completely assigned, and interproton distances were determined using data from rotating-frame nuclear Overhauser enhancement. The backbone dihedral angles were deduced from measurements of coupling constants. The temperature dependence of the amide proton chemical shifts provided information about hydrogen bonding. Six probable solution conformations of viroisin were derived from the use of distance geometry and restrained molecular dynamics based on a set of distance constraints obtained from experimental data. The results of the structural analysis indicate that viroisin has a well ordered conformation in solution. In all these conformations the functional groups essential for toxicity orient themselves in the same direction so as to bind to the target proteins. This feature is consistent with previous results about the formation of a hydrophobic pocket on one side of the molecule.

The Association for Volunteer Administration and professionalization of the field: suggestions from a survey for the membership

This article analyzes results from a comprehensive survey of members of the Association for Volunteer Administration (AVA), conducted in 1992-93. Two-thirds of the membership completed the mail questionnaire. The article elaborates findings from the survey in the areas of: professional background of members, their position in volunteer administration, their volunteer programs, interest in research in the field, and attitudes toward their work, organization, and profession. The concluding section discusses implications of the findings with respect to the AVA and professionalization of the field.

NMR and dynamical simulated annealing studies on the solution conformation of urotensin II

We determined the structure in solution of the vaso-constrictor hormone urotensin II (dodecapeptide) using nuclear magnetic resonance spectroscopy. Complete assignment of all proton resonances has been achieved and the structural information has been obtained from the interproton distance measurements derived from the nuclear Overhauser enhancement data. A combination of distance geometry and dynamical simulated annealing techniques was used to calculate the structure in solution. Nine resultant structures with fewer distance constraint violations were selected that satisfy the experimental restraints very well. The conformation of the molecule in the cyclic hexapeptide segment (core region) is well-defined whereas the N-terminal segment is disordered. This result correlates very well with the earlier predictions about the biologically active and inactive roles played by the core and the N-terminal segment respectively.

Cardiotoxin III from the Taiwan cobra (Naja naja atra). Determination of structure in solution and comparison with short neurotoxins

The structure in solution of cardiotoxin III, a membrane toxin purified from the venom of the Taiwan cobra, Naja naja atra, is reported. Sequence-specific assignment of 1H-NMR lines was completed and the NMR data show the presence of a triple and a double-stranded antiparallel beta-sheet. Many NOE cross peaks identified in NOESY spectra were applied as distance constraints based on a hybrid distance geometry/dynamical simulated annealing technique; 20 structures were found within a single family. The average value of atomic RMS differences between the 20 structures and their geometric mean is 0.087 nm for the backbone atoms and 0.152 nm for all heavy atoms; they are 0.055 nm and 0.12 nm, respectively for the segments of secondary structure. In these selected structures the backbone of the polypeptide chain folds such that five strands emerge from a globular head. Three major loops link these strands to form a double and a triple-stranded antiparallel beta-sheet. Comparison of the structures of the toxin in solution with the X-ray crystal structure of its homologous protein, cardiotoxin V4II from Naja mossambica mossambica, showed good agreement between the structures except at segments of the turns. As the functions of short neurotoxins and cardiotoxins are distinct, despite their similar secondary structural patterns and tertiary folding, a comparative analysis has been carried out between cardiotoxin III and short neurotoxins of known structures. We discuss their structural features in order to clarify relationships between their structure and function.

In search of the real respiratory neurons: culture of medullary fetal cells sensitive to CO2 and low pH

Although extensively pursued, the real respiratory neurons have remained elusive. We departed from the more conventional physiologic and morphologic methods of system and tissue examination and cultured dissociated fetal rat cells from the areas of the nucleus ambiguus and the nucleus tractus solitarius located within the 2 mm rostral to the obex. Pacemaker-like cells, with a regular single or bursting activity, studied at 3-5 weeks of age, responded to very small pulses of CO2 (50 ms) and low pH with an increase in spike frequency and a decrease in amplitude. Other irregularly beating or silent cells did not respond or else required very large pulses (> 200 ms) to do so. The pacemaker cells also responded to hypoxia induced by administration of sodium hydrosulfite with an increase in spike frequency and amplitude; high oxygen (> 600 Torr) and adenosine produced a decrease in electrical activity. Most of these cells were multipolar after staining with antibodies to neuron-specific enolase and fragment C of tetanus toxin. They did not stain for choline acetyltransferase. The results suggest that these cultured cells, expressing a phenotype inherently responsive to CO2 and low pH, have the characteristics of central respiratory chemoreceptors, and may be involved in the generation of the respiratory rhythm.

[Cigarette smoking and circulatory crisis in tissue transfer]

Circulatory crisis occurred in 2 cases of toe-to-hand transfer and 1 case of musculocutaneous free flap after smoking. Two of them failed and 1 survived after exceeding anti-spasm and anti-thrombosis treatment. Experimental studies showed harmful influences of cigarette smoking on endothelial healing process at the vascular anastomosis site, which was covered by endothelial cells in 16%-32% and platelet in 8%-10% of the smoking group 5-10 days after operation, but in 75%-100% and 0% of the normal group. The mechanism and characteristics of circulatory crisis caused by cigarette smoking are discussed.

Design of antineoplastic agents on the basis of the "2-phenylnaphthalene-type" structural pattern. 2. Synthesis and biological activity studies of benzo]b]naphtho[2,3-d]furan-6,11-dione derivatives

Based on the "2-phenylnaphthalene-type" structural pattern hypothesis developed in our laboratory, a number of benzo[b]naphtho[2,3-d]furan-6,11-diones were designed, synthesized, and evaluated in vitro for their inhibitory action against the growth of human promyelocytic leukemia cells (HL-60), small-cell lung cancer (SCLC), SCLC cells resistant to cisplatin (SCLC/CDDP), National Cancer Institute's disease-oriented primary antitumor 60 cell-line panel, and drug-stimulated topoisomerase II-mediated DNA cleavages. Many compounds designed were found to possess potent activity in one or more of the biological tests. In general, activity found in one of the cell lines tested is often echoed in other cell lines and many also expressed substantial inhibitory activity against topoisomerase II-mediated cleavage activities. One of these compounds, 3-[2-(dimethylamino)ethoxy]-1-hydroxybenzo[b]naphthol[2,3-d]furan- 6,11-dione (8j), exhibited strong inhibitory activity throughout the entire series of test panel. Thus, it appears that the proposed structural pattern hypothesis has received substantial support through experimental verification.

Synapse elimination from the mouse neuromuscular junction in vitro: a non-Hebbian activity-dependent process

The effect of action potentials on elimination of mouse neuromuscular junctions (NMJ) was studied in a three-compartment cell culture preparation. Axons from superior cervical ganglion or ventral spinal cord neurons in two lateral compartments formed multiple neuromuscular junctions with muscle cells in a central compartment. The loss of synapses over a 2-7-day period was determined by serial electrophysiological recording and a functional assay. Electrical stimulation of axons from one side compartment during this period, using 30-Hz bursts of 2-s duration, repeated at 10-s intervals, caused a significant increase in synapse elimination compared to unstimulated cultures (p < 0.001). The extent of homosynaptic and heterosynaptic elimination was comparable, i.e., of the 226 functional synapses of each type studied, 111 (49%) of the synapses that had been stimulated were eliminated, and 87 (39%) of unstimulated synapses on the same muscle cells were eliminated. Also, simultaneous bilateral stimulation caused significantly greater elimination of synapses than unilateral stimulation (p < 0.005). These observations are contrary to the Hebbian hypothesis of synaptic plasticity. A spatial effect of stimulus-induced synapse elimination was also evident following simultaneous bilateral stimulation. Prior to stimulation, most muscle cells were innervated by axons from both side compartments, but after bilateral stimulation, muscle cells were predominantly unilaterally innervated by axons from the closer compartment. These experiments suggest that synapse elimination at the NMJ is an activity-dependent process, but it does not follow Hebbian or anti-Hebbian rules of synaptic plasticity. Rather, elimination is a consequence of postsynaptic activation and a function of location of the muscle cell relative to the neuron. An interaction between spatial and activity-dependent effects on synapse elimination could help produce optimal refinement of synaptic connections during postnatal development.

Integration of simian virus 40 into cellular DNA occurs at or near topoisomerase II cleavage hot spots induced by VM-26 (teniposide)

Inhibition of DNA topoisomerase II in simian virus 40 (SV40)-infected BSC-1 cells with a topoisomerase II poison, VM-26 (teniposide), resulted in rapid conversion of a population of the SV40 DNA into a high-molecular-weight form. Characterization of this high-molecular-weight form of SV40 DNA suggests that it is linear, double stranded, and a recombinant with SV40 DNA sequences covalently joined to cellular DNA. The majority of the integrants contain fewer than two tandem copies of SV40 DNA. Neither DNA-damaging agents, such as mitomycin and UV, nor the topoisomerase I inhibitor camptothecin induced detectable integration in this system. In addition, the recombination junctions within the SV40 portion of the integrants correlate with VM-26-induced, topoisomerase II cleavage hot spots on SV40 DNA. These results suggest a direct and specific role for topoisomerase II and possibly the enzyme-inhibitor-DNA ternary cleavable complex in integration. The propensity of poisoned topoisomerase II to induce viral integration also suggests a role for topoisomerase II in a pathway of chromosomal DNA rearrangements.

DNA minor groove-binding ligands: a different class of mammalian DNA topoisomerase I inhibitors

A number of DNA minor groove-binding ligands (MGBLs) are known to exhibit antitumor and antimicrobial activities. We show that DNA topoisomerase (Topo) I may be a pharmacological target of MGBLs. In the presence of calf thymus Topo I, MGBLs induced limited but highly specific single-strand DNA breaks. The 3' ends of the broken DNA strands are covalently linked to Topo I polypeptides. Protein-linked DNA breaks are readily reversed by a brief heating to 65 degrees C or the addition of 0.5 M NaCl. These results suggest that MGBLs, like camptothecin, abort Topo I reactions by trapping reversible cleavable complexes. The sites of cleavage induced by MGBLs are distinctly different from those induced by camptothecin. Two of the major cleavage sites have been sequenced and shown to be highly A + T-rich, suggesting the possible involvement of a Topo I-drug-DNA ternary complex at the sites of cleavage. Different MGBLs also exhibit varying efficiency in inducing Topo I-cleavable complexes, and the order of efficiency is as follows: Hoechst 33342 and 33258 >> distamycin A > berenil > netropsin. The lack of correlation between DNA binding and cleavage efficiency suggest that, in addition to binding to the minor grooves of DNA, MGBLs must also interact with Topo I in trapping Topo I-cleavable complexes.

A structure-activity relationship study of batracylin analogues

A number of isoindolo[1,2-b]quinazolines and some benzo[4,5]isoquinolino[1,2-b]quinazolines as structural modification analogues of the antitumor compound batracylin were synthesized and evaluated against HL-60 cell growth and in topoisomerase II-mediated DNA cleavage assays. Of the compounds studied, 10,12-dihydro-7,8-methylenedioxyisoindolo[1,2-b]quinazolin-1 2(10H)-one (1d), 2-amino-10,12-dihydroisoindolo[1,2-b]quinazolin-12(10H)-one (1p), and 2-amino-7,8-methylenedioxy-10,12-dihydroisoindolo[1,2-b] quinazolin-12(10H)-one (1ab) exhibited good inhibitory activities against HL-60 cell lines as well as induction of topo II-mediated DNA cleavage activities.

The relevance of antibody concentration to the immunohistological quantification of cell proliferation-associated antigens

A number of different factors can profoundly influence the quantification of immunostained cells. Given the characteristics of immunohistological detection systems with non-linearity of signal and antigen concentration, we investigated the relationship of signal (number of stained cells) to the dilution of antibody employed. Three antibodies were studied which have been advocated as being effective in fixed material as markers of cell proliferation: PC10 (anti-proliferating cell nuclear antigen (PCNA)), Ki-S1 and MIB1 (a novel anti-Ki-67). Serial sections of tonsil were immunostained with a range of antibody dilutions using a fixed detection system and the number of stained cells quantified. Similar experiments were performed on tumour xenografts with known growth fraction and, in vitro, on human diploid fibroblasts in logarithmic growth phase. With both PC10 and Ki-S1 the number of stained cells increased with decreasing antibody dilution with no plateau being identified. In contrast, MIB1 showed a clear plateau. Immunocytological data indicate that PCNA and Ki-S1 antigen are present at low (but detectable) levels in at least some non-cycling cells and thus an artificial 'cut-off' has to be employed in assessing the number of proliferating cells with these antibodies. The superiority of MIB1 probably reflects the rapidity of catabolism of the Ki-67 antigen at the end of M phase. Taken together, these data point to the importance of carefully considering fundamental immunochemical properties such as antibody concentration (as well as antibody affinity and sensitivity of detection system) when employing immunological markers of cell proliferation in quantitative procedures.

Chemotaxis of the marine bacterium Vibrio furnissii to sugars. A potential mechanism for initiating the chitin catabolic cascade

Immense quantities of chitin are catabolized by marine bacteria, and this process involves at least three signal transduction systems in Vibrio furnissii. One system, chemotaxis to chitin oligosaccharides, is probably used to colonize chitin particles. But how do the first few cells find this highly insoluble polysaccharide? The following hypothesis is proposed to answer this question: the bacteria respond to soluble chemo-attractants in exudates from injured organisms. Virtually all chitin-producing organisms also contain glucose and/or trehalose, often at high concentrations such as trehalose in insect hemolymph. Chemotaxis of V. furnissii was therefore studied with a variety of sugars. Fructose, ribose, and glycerol are catabolites but not attractants. The cells exhibit weak constitutive taxis to Glc and GlcNAc. After induction, they show a weak response to galactose but are strongly attracted to the following substrates of the phosphoenolpyruvate:glycose phosphotransferase system (PTS): GlcNAc, trehalose, glucose, sucrose, mannose, and mannitol. There is a rough qualitative but no quantitative correlation between the rate of phosphorylation and the chemotactic response to PTS sugars. Trehalose is especially noteworthy because it is phosphorylated at a very rapid rate by uninduced cells but is not an attractant until the cells are induced. We suggest that unidentified inducible factors link the PTS to chemotaxis.

Mutual antagonism between interferon-gamma and tumor necrosis factor-alpha on fibroblast-like synoviocytes: paradoxical induction of IFN-gamma and TNF-alpha receptor expression

We recently described mutual antagonism between IFN-gamma and TNF-alpha on human fibroblast-like synoviocytes (FLS). TNF-alpha inhibits IFN-gamma-induced HLA-DR expression and IFN-gamma blocks TNF-alpha-dependent synoviocyte proliferation, collagenase production, and GM-CSF secretion. To study the mechanism of antagonism we have analyzed the effect these factors on the expression of cytokine surface receptors. 125I-Labeled cytokine binding was measured on cultured FLS and the results were analyzed by Scatchard plots. Unstimulated synoviocytes expressed 9300 +/- 1560 IFN-gamma binding sites per cell. A single class of high-affinity receptor was observed (Kd = 4.5 +/- 2.5 x 10(-10) M). TNF-alpha did not competitively inhibit 125I-IFN-gamma binding. When FLS were incubated with TNF-alpha (100 ng/ml), there was a paradoxical 49.5 +/- 5.6% increase in the number of binding sites for IFN-gamma (P = 0.001), with no change in the Kd. Unstimulated FLS also expressed 2850 +/- 700 TNF-alpha receptors per cells, with a single Kd consistent with the lower-affinity TNF-alpha receptor (7.4 +/- 0.2 x 10(-10) M). IFN-gamma did not directly interfere with TNF-alpha binding. Preincubation of FLS with 100 U/ml of IFN-gamma resulted in a 28.9 +/- 9.0% increase in TNF-alpha receptor expression (P < 0.008), with no change in the Kd. Low levels of the soluble 55-kD TNF receptor were detected in FLS supernatants. IFN-gamma did not effect soluble TNF receptor production.(ABSTRACT TRUNCATED AT 250 WORDS)

Calculating three-dimensional molecular structure of paliurine B from atom-atom distance and restrained energy minimization

The conformation of paliurine B, a 13-membered cyclopeptide alkaloid isolated from Paliurus ramosissimus, has been determined from 2D NMR and distance geometry, followed by the restrained energy minimization calculation. The conformation of the 13-membered ring is well-defined but that of the acyclic dipeptide tail region is relatively disordered. In addition, the cavity in the 13-membered ring is just large enough to insert a magnesium ion but is a little small for calcium or sodium ions.

A new mammalian DNA topoisomerase I poison Hoechst 33342: cytotoxicity and drug resistance in human cell cultures

Hoechst dye 33342 (Ho33342), like many other DNA minor groove binding ligands and its parent compound Hoechst dye 33258 (Ho33258), nonspecifically inhibits the catalytic activities of many DNA enzymes. However, both Ho33258 and Ho33342 also specifically interrupt the breakage/reunion reaction of mammalian DNA topoisomerase I by trapping reversible topoisomerase I cleavable complexes. The enhanced membrane permeability of Ho33342 over its parent compound Ho33258 has allowed studies of the cellular action of Ho33342. Our results suggest that Ho33342 also traps topoisomerase I but not topoisomerase II into reversible cleavable complexes in human KB cells. Although Ho33342 shares a similar mechanism of action with camptothecin, a prototypic topoisomerase I poison, in trapping topoisomerase I cleavable complexes, Ho33342 differs from camptothecin in its effect on drug-resistant cells. Different from camptothecin, Ho33342 was shown to be about 200-fold less cytotoxic in MDR1-overexpressing human KB V1 cells relative to parental human KB 3-1 cells. Ho33342 is only 5-fold less cytotoxic for camptothecin-resistant CPT-K5 cells, which expresses a highly camptothecin-resistant from of topoisomerase I, than for the wild type human lymphoblast RPMI 8402 cells. Our studies suggest a potential use of Hoechst 33342 as a new topoisomerase I poison in antitumor chemotherapy.

Solution conformation of cobrotoxin: a nuclear magnetic resonance and hybrid distance geometry-dynamical simulated annealing study

The solution conformation of cobrotoxin has been determined by using proton nuclear magnetic resonance spectroscopy. With the combination of various two-dimensional NMR techniques, the 1H-NMR spectrum of cobrotoxin was completely assigned (Yu et al., 1990). A set of 435 approximate interproton distance restraints was derived from nuclear Overhauser enhancement (NOE) measurements. These NOE constraints, in addition to the 29 dihedral angle constraints (from coupling constant measurements) and 26 hydrogen bonding restraints (from the pattern of short-range NOEs), form the basis of 3-D structure determination by the hybrid distance geometry-dynamical simulated annealing method. The 23 structures that were obtained satisfy the experimental restraints, display small deviation from idealized covalent geometry, and possess good nonbonded contacts. Analysis of converged structures indicated that there are two antiparallel beta sheets (double and triple stranded), duly confirming our earlier observations. These are well defined in terms of both atomic root mean square (RMS) differences and backbone torsional angles. The average backbone RMS deviation between the calculated structures and the mean structure, for the beta-sheet regions, is 0.92 A. The mean solution structure was compared with the X-ray crystal structure of erabutoxin b, the homologous protein. This yielded information that both structures resemble each other except at the exposed loop/surface regions, where the solution structure seems to possess more flexibility.

An analysis of the correlation between angiographic and clinical findings in cerebral arteriovenous malformations

One hundred and sixty-seven cases of cerebral arteriovenous malformations (AVMs) confirmed by digital subtract angiography (DSA) and surgery were analyzed to find the correlation between clinical and angiographic findings with regard to sex, age, size of angioma, and number of drainage veins and feeding arteries. Statistical analysis showed that the risk of hemorrhage was highest in small AVMs with only one drainage vein, and decreased with increases of volume and number of AVMs. Statistics also demonstrated that small AVMs usually have one drainage vein and so have a high risk of hemorrhage.

Uptake of antisense oligonucleotides and functional block of acetylcholine receptor subunit gene expression in primary embryonic neurons

Several recent studies have used antisense oligonucleotides in the nervous system to probe the functional role of particular gene products. Since antisense oligonucleotide-mediated block of gene expression typically involves uptake of the oligonucleotides, we have characterized the mechanism of this uptake into developing neurons from embryonic chickens. Antisense oligonucleotides (15 mers) added to the bathing media are taken up into the embryonic chicken sympathetic neurons maintained in vitro. A portion of the oligonucleotide uptake is temperature dependent and saturates at extracellular oligonucleotide concentrations > or = 20 microM. This temperature sensitive, saturable component is effectively completed by single nucleotides of ATP and AMP and is reminiscent of receptor-mediated endocytosis of oligonucleotides described in non-neuronal cells. The efficiency of the oligonucleotide uptake system is dependent on the developmental stage of the animal but independent of the number of days that the neurons are maintained in vitro. Following the uptake of antisense oligonucleotides directed against ion channel subunit genes expressed by these neurons (nicotinic acetylcholine receptor subunit alpha 3; nAChR alpha 3), biophysical assays reveal that the functional expression of the target gene is largely blocked. Thus the number of wild type nAChR channels expressed is decreased by approximately 80%-90%. Furthermore, following antisense deletion of alpha 3, "mutant" nAChRs with distinct functional characteristics are expressed. In sum, these studies characterize the uptake of antisense oligonucleotide and demonstrate the functional block of specific gene expression in primary developing neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

In search of the central respiratory neurons: II. Electrophysiologic studies of medullary fetal cells inherently sensitive to CO2 and low pH

Although extensively pursued, the central respiratory neurons have remained elusive. We departed from the more conventional physiologic and morphologic methods of system and tissue examination and cultured dissociated fetal rat cells (Fitzgerald et al., J Neurosci Res 33:579-589, 1992) from the area of the nucleus ambiguus and the nucleus tractus solitarius located within the 2 mm rostral to the obex. Pacemaker-like cells, with a regular single or bursting activity, studied at 3-5 weeks of age, responded to very small pulses of CO2 (50 ms) and low pH with an increase in spike frequency and a decrease in spike amplitude. Other irregularly beating or silent cells did not respond or else required very large pulses (> 200 ms) to do so. The pacemaker cells also responded to hypoxia induced by administration of sodium hydrosulfite with an increase in spike frequency and amplitude; high oxygen (> 600 torr) and adenosine produced a decrease in electrical activity. Most of these cells were multipolar after staining with antibodies to neuron-specific enolase (NSE) and Fragment C of tetanus toxin. They did not stain for choline acetyltransferase (ChAT). The results suggest that these cultured cells, expressing a phenotype inherently responsive to CO2 and low pH, have the characteristics of central respiratory chemoreceptors, and may be involved in the generation of the respiratory rhythm.

Study of experimental hypoparathyroidism in rats. III. Fluidity changes in brain synaptolemma

The changes of brain synaptolemma fluidity in experimental parathyroidectomized (PTX) rats were studied by using fluorescence polarization and differential scanning calorimetry (DSC) techniques. The results showed that microviscosity (eta) of the rat brain synaptolemma in the cerebral cortex, hippocampus, midbrain and striatum were decreased after a 2-month period of continuous hypocalcemia, and in the hippocampus and cerebral cortex it was decreased significantly as compared with control. These results suggest that the fluidity of the synaptolemma in the brains of hypocalcemic rats is increased. In addition, hypocalcemia also lowered the Tc of hippocampus synaptolemma lipid, which indicates that both fluidity and permeability had increased in these rats.

In search of the central respiratory neurons: I. Dissociated cell cultures of respiratory areas from the upper medulla

Dissociated cells from the areas of the nucleus ambiguus and the nucleus tractus solitarius obtained by tissue punch or block dissection from coronal slices of the medulla at the level of the obex were cultured from fetal rats at 18 to 21 days gestation. The dissociated neurons were plated either directly in vitrogen-coated 35 mm tissue culture dishes or in such dishes which had been seeded with subcultures of cortex- or medulla-derived astrocytes. After the astrocytes reached confluency and were treated with an antimitotic agent, dissociated nucleus ambiguus or nucleus tractus solitarius was plated at 0.5-1.0 x 10(6) cells per dish. Neurons grew well on monolayers of medullary or cortical astrocytes, but survived poorly on vitrogen-coated dishes without a cellular substrate. Rat medulla was preferred as the source of astrocytes. Tissue dissociation with papain rather than trypsin produced less cellular debris, and the neuronal yield from the tissue was higher. The neuronal population was heterogenous in morphology including small and large bipolar, pyramidal, and multipolar cells. Neurons sensitive to CO2 and/or low pH (Rigatto et al., J Neurosci Res 33:590-597, 1992) did not appear to have any definitive morphologic characteristics, but most were multipolar. These neurons stained well with antibodies to neuron-specific enolase and Fragment C of tetanus toxin, but not to choline acetyltransferase (ChAT). These findings suggest that neurons possibly responsible for the central regulation of respiration can be maintained for several weeks in dissociated cell culture, providing a system for neurotransmitter, electrophysiological, and morphological studies.

Beneficial effects of berberine on hemodynamics during acute ischemic left ventricular failure in dogs

In 18 dogs ischemic left ventricular failure characterized by a 30 percent reduction in peak rate of rise of left ventricular pressure (+dp/dt) and elevation of left ventricular end-diastolic pressure (LVEDP) to 15 mmHg or more was produced by ligation of the proximal left anterior descending coronary artery followed by serial occlusions of the distal left circumflex coronary artery. In 10 days, administration of berberine in an intravenous bolus injection (1 mg/kg, within 3 minutes) followed by a constant infusion (0.2 mg/kg/min, 30 minutes) increased the cardiac output (CO) from 1.25 +/- 0.12 to 1.61 +/- 0.17 L/min (P < 0.05), and +dp/dt from 810 +/- 85 to 1021 +/- 130 mmHg/s (P < 0.01), and decreased LVEDP from 16.5 +/- 1.3 to 12.0 +/- 1.0 mmHg (P < 0.05), diastolic blood pressure from 94 +/- 6 to 84 +/- 5 mmHg (P < 0.01), systemic vascular resistance from 7303 +/- 278 to 5442 +/- 231 dynes.x/cm5 (P < 0.01), but did not affect the heart rate. Injection of 5% glucose with the same volume did not improve CO and dp/dt (P > 0.05) but increased the LVEDP from 17.1 +/- 1.4 to 17.8 +/- 1.6 mmHg (P < 0.01) in 8 dogs. The levels of plasma concentration of berberine was determined with high-performance liquid chromatography. The changes in plasma drug level were found parallel to hemodynamic effects of berberine. The results of this study showed that berberine was able to improve the impaired left ventricular function by its positive inotropic effect and mild systemic vasodilatation.

Conformational properties of oxytocin in dimethyl sulfoxide solution: NMR and restrained molecular dynamics studies

The conformation of oxytocin, the neurohypophyseal nonapeptide hormone, in solution in deuterated dimethyl sulfoxide has been determined by 1H-nmr. The structural determination is based on the experimental data set of nuclear Overhauser effect restraints. Obtained after the restrained molecular dynamics simulation on an initial structure of extended conformation, five resultant structures satisfy the experimental restraints well. These structures resemble that of the crystal structure of deamino-oxytocin, an analogue of oxytocin, in terms of a close correlation observed both at two beta-turn regions of the 20-membered tocin ring and at the tripeptide tail end. Based on this comparison and analysis of restrained molecular dynamics trajectories, we found that, although the turns are stabilized by the formation of hydrogen bonds, the oxytocin molecule possesses a slight twist in DMSO solution relative to the orientation of deamino-oxytocin in the crystalline state. Analyses of oxytocin conformation indicate that the tripeptide tail is more flexible than the tocin ring.

Structure of the oxidized long-chain flavodoxin from Anabaena 7120 at 2 A resolution

The structure of the long-chain flavodoxin from the photosynthetic cyanobacterium Anabaena 7120 has been determined at 2 A resolution by the molecular replacement method using the atomic coordinates of the long-chain flavodoxin from Anacystis nidulans. The structure of a third long-chain flavodoxin from Chondrus crispus has recently been reported. Crystals of oxidized A. 7120 flavodoxin belong to the monoclinic space group P2(1) with a = 48.0, b = 32.0, c = 51.6 A, and beta = 92 degrees, and one molecule in the asymmetric unit. The 2 A intensity data were collected with oscillation films at the CHESS synchrotron source and processed to yield 9,795 independent intensities with Rmerg of 0.07. Of these, 8,493 reflections had I > 2 sigma and were used in the analysis. The model obtained by molecular replacement was initially refined by simulated annealing using the XPLOR program. Repeated refitting into omit maps and several rounds of conjugate gradient refinement led to an R-value of 0.185 for a model containing atoms for protein residues 2-169, flavin mononucleotide (FMN), and 104 solvent molecules. The FMN shows many interactions with the protein with the isoalloxazine ring, ribityl sugar, and the 5'-phosphate. The flavin ring has its pyrimidine end buried into the protein, and the functional dimethyl benzene edge is accessible to solvent. The FMN interactions in all three long-chain structures are similar except for the O4' of the ribityl chain, which interacts with the hydroxyl group of Thr 88 side chain in A. 7120, while with a water molecule in the other two. The phosphate group interacts with the atoms of the 9-15 loop as well as with NE1 of Trp 57. The N5 atom of flavin interacts with the amide NH of Ile 59 in A. 7120, whereas in A. nidulans it interacts with the amide NH of Val 59 in a similar manner. In C. crispus flavodoxin, N5 forms a hydrogen bond with the side chain hydroxyl group of the equivalent Thr 58. The hydrogen bond distances to the backbone NH groups in the first two flavodoxins are 3.6 A and 3.5 A, respectively, whereas in the third flavodoxin the distance is 3.1 A, close to the normal value. Even though the hydrogen bond distances are long in the first two cases, still they might have significant energy because their microenvironment in the protein is not accessible to solvent.(ABSTRACT TRUNCATED AT 400 WORDS)

NMR study of the solution conformation of actinomycin D

The solution conformation of actinomycin D, the Gram-positive antibiotic and DNA-binding drug, has been determined by 1H-NMR in deuterated dimethyl sulfoxide. The structure determination is based on the experimental data set of NOE restraints. Four structures were obtained from the distance geometry and restrained molecular dynamics calculation. The resultant structures satisfy the experimental restraints very well. These structures are found to be compatible with the X-ray crystal structures.

IL-1 receptor antagonist protein production and gene expression in rheumatoid arthritis and osteoarthritis synovium

IL-1 can participate in the perpetuation of arthritis through direct stimulation of synoviocytes and augmentation of matrix degradation. Hence, local production of the IL-1R antagonist protein (IRAP) might be an important negative feedback signal that regulates synovitis. We assessed synovial IRAP production in synovia from 30 individuals, by using a specific mAb and the immunoperoxidase staining method. IRAP was detected in 11 of 12 rheumatoid arthritis (RA) synovial tissues (ST) and was located primarily in the sublining, particularly in perivascular regions enriched for macrophages. Some staining was observed in the intimal lining of the synovium, although this was significantly less than in the sublining (p less than 0.05). Nine of 12 osteoarthritis (OA) tissues were positive for IRAP. In contrast to RA, the staining was observed primarily in the synovial lining in OA, with only minimal sublining IRAP being detected. Synovia from four patients without arthritis were negative (three autopsy specimens and one post-traumatic sample). Of the other two patients with miscellaneous diagnoses, one sample was negative (tenosynovitis) and one was positive (seronegative inflammatory arthritis) (sublining). Studies of serial sections and double-immunostaining experiments indicated that macrophages are the major cells containing immunoreactive IRAP. IRAP gene expression in vivo was determined by performing in situ hybridization on ST from 17 arthritis patients. RNA sense IRAP probes did not hybridize to any tissues. Anti-sense IRAP probes bound to two of nine RA tissues, two of six OA tissues, one of one seronegative inflammatory arthropathy tissue, and none of one flexor tenosynovitis tissue. As with immunoreactive protein, IRAP mRNA was primarily localized to cells in the synovial lining in OA but was more prominent in perivascular lymphoid aggregates in RA and seronegative inflammatory arthropathy. Northern blot analysis was performed on RNA isolated from nine ST. The appropriately sized IRAP band was identified in six of nine samples (five of six RA and one of three OA). Supernatants from cultured RA and OA ST cells contained immunoreactive and biologically active IRAP. Hence, IRAP gene expression and protein production occur in RA and OA synovium, albeit in different distributions.

Multiple-model adaptive predictive control of mean arterial pressure and cardiac output

A multiple-model adaptive predictive controller has been designed to simultaneously regulate mean arterial pressure and cardiac output in congestive heart failure subjects by adjusting the infusion rates of nitroprusside and dopamine. The algorithm is based on the multiple-model adaptive controller and utilizes model predictive controllers to provide reliable control in each model subspace. A total of 36 linear small-signal models were needed to span the entire space of anticipated responses. To reduce computation time, only the six models with the highest probabilities were used in the control calculations. The controller was evaluated on laboratory animals that were either surgically or pharmacologically altered to exhibit symptoms of congestive heart failure. During trials, the controller performance was robust with respect to excessive switching between models and nonconvergence to a single dominant model. A comparison is also made with a previous multiple-drug controller design.

[Report on first finding an epidemic of Scrub typhus in north rural areas]

In the autumn of 1989 and 1990, an epidemic of Scrub typhus occurred in north rural areas in Tianjin. The authors investigated the epidemic on clinical, epidemiological, serological and etiological features, 44 patients were diagnosed serologically or clinically as Scrub typhus and 42 of them (95.5%) were diagnosed serologically by IFA method. 10 sera specimens collected from the patients were determined distinctively by CF method, 8 of them were > or = 1:20 titre to Gilliam type antigen of tsutsugamushi. The try for isolating pathogens failed of success. The epidemic areas is situated in 39.45'-40.05' north latitudes and showed it was the new epidemic area in the north of China.

[A research on the quality of radix Astragali]

Milkvetch root (Radix Astragali) and its likes were determined in their contents of trace elements, total extracts and astragalin A. The result showed there was some relationship between the drug quality, trace-element contents, difference of species, growing areas and on-the-spot processing methods.

IL-1 receptor antagonist protein production and gene expression in rheumatoid arthritis and osteoarthritis synovium

IL-1 can participate in the perpetuation of arthritis through direct stimulation of synoviocytes and augmentation of matrix degradation. Hence, local production of the IL-1R antagonist protein (IRAP) might be an important negative feedback signal that regulates synovitis. We assessed synovial IRAP production in synovia from 30 individuals, by using a specific mAb and the immunoperoxidase staining method. IRAP was detected in 11 of 12 rheumatoid arthritis (RA) synovial tissues (ST) and was located primarily in the sublining, particularly in perivascular regions enriched for macrophages. Some staining was observed in the intimal lining of the synovium, although this was significantly less than in the sublining (p less than 0.05). Nine of 12 osteoarthritis (OA) tissues were positive for IRAP. In contrast to RA, the staining was observed primarily in the synovial lining in OA, with only minimal sublining IRAP being detected. Synovia from four patients without arthritis were negative (three autopsy specimens and one post-traumatic sample). Of the other two patients with miscellaneous diagnoses, one sample was negative (tenosynovitis) and one was positive (seronegative inflammatory arthritis) (sublining). Studies of serial sections and double-immunostaining experiments indicated that macrophages are the major cells containing immunoreactive IRAP. IRAP gene expression in vivo was determined by performing in situ hybridization on ST from 17 arthritis patients. RNA sense IRAP probes did not hybridize to any tissues. Anti-sense IRAP probes bound to two of nine RA tissues, two of six OA tissues, one of one seronegative inflammatory arthropathy tissue, and none of one flexor tenosynovitis tissue. As with immunoreactive protein, IRAP mRNA was primarily localized to cells in the synovial lining in OA but was more prominent in perivascular lymphoid aggregates in RA and seronegative inflammatory arthropathy. Northern blot analysis was performed on RNA isolated from nine ST. The appropriately sized IRAP band was identified in six of nine samples (five of six RA and one of three OA). Supernatants from cultured RA and OA ST cells contained immunoreactive and biologically active IRAP. Hence, IRAP gene expression and protein production occur in RA and OA synovium, albeit in different distributions.

Metabolism in and function of the central dopamine system after transplanting adrenal medullary tissue into the rat brain

The unilateral nigrostriatal pathway of rats was destroyed by microinjecting 6-hydroxydopamine (6-OH-DA), and isogenous rat adrenal medullary tissue was then transplanted into the lesioned lateral caudate nucleus. After 2 months, rotational movement was almost abolished in 40% of the transplanted rats, and it was significantly reduced in the remaining 60%. Dopamine (DA) and its metabolites contents were significantly decreased in the lesioned side of the forebrain, while no changes of NA were found. After transplanting adrenal medullary tissue, the DA contents increased by 9% only, whereas the NA contents increased significantly. In addition, by examining synaptosomes in the brains of these rats, we found that on the lesioned side of nontransplanted rats, DA uptake and DA receptor binding were increased significantly, while no such changes were seen in the transplanted group.