[Effect of bone marrow transplantation conditioning regimen on thyroid and adrenocortical functions in patients with blood diseases]

OBJECTIVE

In order to investigate the life quality of patients with hematological diseases after bone marrow transplantation (BMT).

METHODS

Pituitary-thyroid and adrenocortical function were de tected in 29 patients with hematological diseases before and after BMT.

RESULTS

All patients had normal thyroid and adrenocortical functions before BMT. As compared with pre-BMT,the median serum TSH levels were significantly increased at 3, 6, 12 (P<0.01), 24-60 (P<0.05) months post-BMT. The adrenocortical function had no change in all patients, and thyroid dysfunction were found in 6 of 24 patients detected at a median time of 6 month post-BMT. Five of the 6 thyroid dysfuntion patients developed hypothyroidism, and one hyperthyroidism.

CONCLUSION

There was little effect of conditioning regimen on adrenocortical function, while thyroid dysfunction was common after BMT. Long term follow up on thyroid function in patients after BMT is necessary.

[In vitro reversal of homoharringtonine resistance by the combination of tamoxifen and verapamil]

OBJECTIVE

To investigate the reversal of homoharringtonine (HHT)-resistance by tamoxifen (TAM) or verapamil (VER) alone or in combination.

METHODS

The drug-sensitivity test was performed with semisolid agar culture.

RESULTS

The cytotoxicity of HHT to K562/S cells was not enhanced by TAM or VER alone or in combination,but HHT resistance in HHT resistant cells (K562/H20) was reversed by VER and TAM at nontoxic doses (4micromol/L or 8micromol/L). The IC50 of K562/H20 for HHT decreased from 446.8 +/- 0.08microg/L to 45.1 +/- 0.02microg/L in the presence of 4micromol/L of VER, to 22.4 +/- 0.03microg/L in 8micromol/L of VER, to 85.1 +/- 0.03microg/L in 4micromol/L of TAM and to 26.4 +/- 0.02microg/L in 8micromol/L of TAM. In the presence of combinations of 2micromol/L VER and 4micromol/L TAM and of 2micromol/L VER and 8micromol/L TAM, IC50 of K562/H20 decreased to 30.4 +/- 0.02microg/L and 4.3 +/- 0.04microg/L, respectively.

CONCLUSION

HHT-resistance could be reversed by VER or TAM alone, and the combination of the two drugs showed a synergistic effect.

[Effect of adrenomedullin on mesenteric microvessels and microlymphatics in rat]

The dilatant effect of adrenomedullin (ADM), a novel peptide of 52 amino acids, on the mesenteric microvessels and microlymphatics was investigated under microscopic observation. 10(-6) mol/L ADM could also ameliorate alteration of the hemorheology induced by 10(-5) mol/L norepinephrine (NE) or 10(-7) mol/L endothelin (ET). However, this ameliorative response was markedly inhibited in the presence of NG-nitro-L-arginine (L-NNA), an inhibitor for production of nitric oxide.

The effects of amino acid replacements of glycine 121 on transmembrane helix 3 of rhodopsin

Rhodopsin is a member of a family of G protein-coupled receptors with seven transmembrane (TM) helices. In rhodopsin, Gly121 is a highly conserved amino acid residue near the middle of TM helix 3. TM helix 3 is known to be involved in chromophore-protein interactions and contains the chromophore Schiff base counterion at position 113. We prepared a set of seven single amino acid replacement mutants of rhodopsin at position 121 (G121A, Ser, Thr, Val, Ile, Leu, and Trp) and control mutants with replacements of Gly114 or Ala117. The mutant opsins were expressed in COS cells and reconstituted with either 11-cis-retinal, the ground-state chromophore of rhodopsin, or all-trans-retinal, the isomer formed upon receptor photoactivation. The replacement of Gly121 resulted in a relative reversal in the selectivity of the opsin apoprotein for reconstitution with 11-cis-retinal over all-trans-retinal in COS cell membranes. The mutant pigments also were found to be thermally unstable to varying degrees and reactive to hydroxylamine in the dark. In addition, the size of the residue substituted at position 121 correlated directly to the degree of blue-shift in the lambdamax value of the pigment. These results suggest that Gly121 is an important and specific component of the 11-cis-retinal binding pocket in rhodopsin.

Functional interaction of transmembrane helices 3 and 6 in rhodopsin. Replacement of phenylalanine 261 by alanine causes reversion of phenotype of a glycine 121 replacement mutant

Replacement of a highly conserved glycine residue on transmembrane (TM) helix 3 of bovine rhodopsin (Gly121) by amino acid residues with larger side chains causes a progressive blue-shift in the lambdamax value of the pigment, a decrease in thermal stability, and an increase in reactivity with hydroxylamine. In addition, mutation of Gly121 causes a relative reversal in the selectivity of opsin for 11-cis-retinal over all-trans-retinal. It was suggested that Gly121 plays an important role in defining the 11-cis-retinal binding pocket of rhodopsin (Han, M., Lin, S. W., Smith, S. O., and Sakmar, T. P. (1996) J. Biol. Chem. 271, 32330-32336). Here, we combined the mutant opsin G121L with second site replacements of four different amino acid residues on TM helix 6: Met257, Val258, Phe261, or Trp265. We show that the loss of function phenotypes of the G121L mutant described above can be partially reverted specifically by the mutation of Phe261, a residue highly conserved in all G protein-coupled receptors. For example, the double-replacement mutant G121L/F261A has spectral, chromophore-binding, and transducin-activating properties intermediate between those of G121L and rhodopsin. This rescue of the G121L defects did not occur with the other second site mutations tested. We conclude that specific portions of TM helices 3 and 6, which include Gly121 and Phe261, respectively, define the chromophore-binding pocket in rhodopsin. Finally, the results are placed in the context of a molecular graphics model of the TM domain of rhodopsin, which includes the retinal-binding pocket.

[The effect of brain-derived neurotrophic factor on regeneration of nerve fibers after crush injury--morphometric evaluation]

Brain-derived neurotrophic factor (BDNF) is produced in Schwann cells and fibroblasts in the peripheral nerve, and is considered to play an important role in survival, maintenance, development and repair of the peripheral neuron. In this study, the effect of human recombinant BDNF on the regeneration of nerve fibers following a crush injury to the sciatic nerves of Sprague-Dawley rats was evaluated. In the experimental group, 20 mg/kg of BDNF was injected subcutaneously three times a week for 4 weeks in seven rats. In the control group, only the dissolving solution used in the experimental group was injected similarly in seven rats as in the experimental group. The various morphometric parameters were evaluated in the peroneal, sural and tibial nerves and the nerve to soleus muscle distal to the crush site. There were no statistically significant differences in the change of body weight, the improvement of the width between the first and fifth toes on the side of the crush, the density of total myelinated fibers (numbers per mm2), the total number of myelinated fibers (number per nerve), maximum and median diameters of myelinated fibers, the density of unmyelinated fibers, and the electron microscopic parameters of axon and myelin sheath. On the other hand, the number of myelin lamellae in relation to the transverse axonal area was significantly greater in the experimental group than in the control group. Therefore, BDNF may promote the myelination. However, such an effect on myelination seems not to be clinically significant, because such an effect was not demonstrated in other morphometric evaluations reflecting the myelination condition. Therefore, taking all the data obtained in this study into consideration, we concluded that there was no definite evidence that BDNF promoted the regeneration of nerve fibers at least under these experimental conditions.

D-Lysergyl peptide synthetase from the ergot fungus Claviceps purpurea

The ergot fungus Claviceps purpurea produces the medically important ergopeptines, which consist of a cyclol-structured tripeptide and D-lysergic acid linked by an amide bond. An enzyme activity capable of non-ribosomal synthesis of D-lysergyl-L-alanyl-L-phenylalanyl-L-proline lactam, the non-cyclol precursor of the ergopeptine ergotamine, has been purified about 18-fold from the ergotamine-producing C. purpurea strain D1. Analysis of radioactively labeled enzyme-substrate complexes revealed a 370-kDa lysergyl peptide synthetase 1 (LPS 1) carrying the amino acid activation domains for alanine, phenylalanine, and proline. The activation of D-lysergic acid is catalyzed by a 140-kDa peptide synthetase (LPS 2) copurifying with LPS 1. LPS 1 and LPS 2 contain 4'-phosphopantetheine and bind their substrates covalently by thioester linkage. Kinetic analysis of the synthesis reaction revealed a Km of approximately 1.4 microM for both D-lysergic acid and its structural homolog dihydrolysergic acid, which is one to two orders of magnitude lower than the Km values for the other amino acids involved. The Km values for the amino acids reflect their relative concentrations in the cellular pool of C. purpurea. This may indicate that in in vivo conditions D-lysergyl peptide formation is limited by the D-lysergic acid concentration in the cell. In vitro, the multienzyme preparation catalyzes the formation of several different D-lysergyl peptide lactams according to the amino acids supplied. Specific antiserum was used to detect LPS 1 in various C. purpurea strains. In C. purpurea wild type, the enzyme was expressed at all stages of cultivation and in different media, suggesting that it is produced constitutively.

Neurosteroid analogues. 4. The effect of methyl substitution at the C-5 and C-10 positions of neurosteroids on electrophysiological activity at GABAA receptors

A series of analogues of the neuroactive steroids 3 alpha-hydroxy-5 alpha-pregnan-20-one and 3 alpha-hydroxy-5 beta-pregnan-20-one were studied to elucidate the mode of binding of 5 alpha-and 5 beta-reduced steroids to steroid binding sites on GABAA receptors. Analogues which were either 3 alpha-hydroxy-20-ketosteroids or 3 alpha-hydroxysteroid-17 beta-carbonitriles and which contained various methyl group substitution patterns at C-5 and C-10 were prepared. Evaluations utilized whole-cell patch clamp electrophysiological methods carried out on cultured rat hippocampal neurons, and the results obtained with the rigid 17 beta-carbonitrile analogs were analyzed using molecular modeling methods. The molecular modeling results provide a rationale for the observation that the configuration of the hydroxyl group at C-3 is a greater determinant of anesthetic potency than the configuration of the A,B ring fusion at C-5. The electrophysiological results identify steric restrictions for the space that can be occupied in 5 alpha- and 5 beta-reduced steroid modulators of GABAA receptors in the regions of space proximate to the steroid C-5, C-10, and possibly C-4 positions. This information is useful for the development of nonsteroidal analogues that can modulate GABAA receptors via interactions at steroid binding sites.

Increased expression of PDGF and c-myc genes in lungs and pulmonary arteries of pulmonary hypertensive rats induced by hypoxia

The role of growth factors and proto-oncogene in pulmonary vascular structural remodelling is not well known. The present study examined gene expression of platelet-derived growth factor (PDGF)-A and -B chain and proto-oncogene, c-myc, in lung tissue and pulmonary artery of rats exposed to hypoxia and compared to those levels of gene expression in normal rats. Normal lungs and pulmonary artery expressed PDGF-A chain transcript of 1.7 kb and PDGF-B chain transcript of 3.5 Kb. The c-myc transcript of 2.2 kb was expressed as well. After hypoxic exposure for 7 and 14 days mRNA levels of PDGF-B chain and c-myc were elevated significantly compared with those of control rats. PDGF-A chain mRNA increased after hypoxia for 7 days, and then declined. These results suggest that activation of autocrine and/or paracrine is important in proliferation mechanism of pulmonary artery smooth muscle cells in hypoxic pulmonary hypertensive rats.

In vitro expansion of murine hematopoietic progenitor cells by leukemia inhibitory factor, stem cell factor, and interleukin-1 beta

Murine hematopoietic progenitor cells were markedly expanded in the presence of leukemia inhibitory factor (LIF), interleukin (IL)-1 beta and/or stem cell factor (SCF), although SCF+IL-1 beta +IL-3, LIF+SCF+IL-3, and SCF+IL-1 beta showed an appreciable effect on the in vitro expansion of hematopoietic progenitor cells as well. In the presence of LIF+SCF+IL-1 beta, highly proliferative potential colony-forming units (CFU-HPP) and colony forming units of mixed lineages (CFU-Mix) were more efficiently expanded than colony forming units granulocytes/macrophage (CFU-GM) and burst-forming units of erythroid lineage (BFU-E) compared with the colony formations of freshly obtained bone marrow cells. The cell yield on day 5 in the presence of LIF+SCF+IL-1 beta was comparable to that in SCF+IL-1 beta and SCF+IL-1 beta +IL-3. Nevertheless, colony formations were marked in LIF+SCF+IL-1 beta, thus suggesting that this combination can generate hematopoietic progenitor cells that possess greater potential for CFU-HPP, CFU-Mix, CFU-GM, and BFU-E colony formations. Hematopoietic cells expanded in the presence of LIF+SCF+IL-1 beta showed increased mRNA expressions of IL-1 beta, IL-3, IL-6, granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage (GM)-CSF, interferon gamma (IFN-gamma), and LIF compared with those of nontreated hematopoietic cells. Furthermore, LIF+SCF+IL-1 beta induced increased IL-3 and GM-CSF mRNA expression in hematopoietic cells but induced decreased macrophage inflammatory protein 1 alpha (MIP1 alpha) mRNA expression as compared with SCF+IL-1 beta +IL-3. These results suggest that the balance between stimulatory and inhibitory cytokines plays an important role in in vitro expansion of hematopoietic progenitor cells.

A Ras-mediated signal transduction pathway is involved in the control of sex myoblast migration in Caenorhabditis elegans

Sex myoblast migration in the Caenorhabditis elegans hermaphrodite represents a simple, genetically amenable model system for studying how cell migration is regulated during development. Two separable components of sex myoblast guidance have been described: a gonad-independent mechanism sufficient for the initial anterior migration to the mid-body region, and a gonad-dependent mechanism required for precise final positioning (J. H. Thomas, M. J. Stern and H. R. Horvitz (1990) Cell 62, 1041–1052). Here, we demonstrate a role for a Ras-mediated signal transduction pathway in controlling sex myoblast migration. Loss-of-function mutations in let-60 ras, ksr-1, lin-45 raf, let-537/mek-2 or sur-1/mpk-1 cause defects in sex myoblast final positions that resemble those seen in gonad-ablated animals, while constitutively active let-60 ras(G13E) trans-genes allow fairly precise positioning to occur in the absence of the gonad. A mosaic analysis demonstrated that let-60 ras is required within the sex myoblasts to control proper positioning. Our results suggest that gonadal signals normally stimulate let-60 ras activity in the sex myoblasts, thereby making them competent to sense or respond to positional cues that determine the precise endpoint of migration. let-60 ras may have additional roles in sex myoblast guidance as well. Finally, we have also investigated genetic interactions between let-60 ras and other genes important for sex myoblast migration, including egl-15, which encodes a fibroblast growth factor receptor tyrosine kinase (D. L. DeVore, H. R. Horvitz and M. J. Stern (1995) Cell 83, 611–623). Since mutations reducing Ras pathway activity cause a different phenotype than those reducing egl-15 activity and since constitutive Ras activity only partially suppresses the migration defects of egl-15 mutants, we argue that let-60 ras and egl-15 do not act together in a single linear pathway.

Effects of temperature and humidity on the performance of polymer-coated surface acoustic wave vapor sensor arrays

The influences of temperature and atmospheric humidity on the performance of an array of eight polymer-coated 158-MHz surface acoustic wave vapor sensors were investigated. Sensitivities to the seven organic vapors examined all exhibited negative Arrhenius temperature dependencies, with responses increasing by factors of 1.5-4.4 on going from 38 to 18 degrees C. The magnitudes of the temperature effects, while generally similar, differed sufficiently among certain sensor-vapor combinations to cause marked changes in vapor response patterns. In addition, it was found that operating identically coated sensors at different temperatures could provide a means for discriminating certain vapors. The changes in sensor responses with temperature agreed reasonably well with those expected assuming ideal vapor sorption behavior and indicated that changes in the moduli of the sensor coatings were not important mediating factors. Responses to relative humidity (RH) from 0 to 85% RH were important even for the nonpolar sensor coatings. Significant changes in the sensitivities to the organic vapors were observed as a function of atmospheric humidity for several sensor-vapor combinations, which, in turn, affected the patterns of responses obtained from the sensor array. Results indicate that small changes in temperature or humidity have a larger effect on baseline stabilities than on the responses to the vapors. Monte Carlo simulations of sensor responses show that the ability to discriminate vapors in binary and ternary mixtures using a four-sensor array remains high regardless of the operating temperature and ambient humidity, provided that temperature-or humidity-induced changes in the response patterns are taken into account.

Control and integration of cell signaling pathways during C. elegans vulval development

Vulval development in the Caenorhabditis elegans hermaphrodite represents a simple, genetically tractable system for studying how cell signaling events control cell fate decisions. Current models suggest that proper specification of vulval cell fates relies on the integration of multiple signaling systems, including one that involves a receptor tyrosine kinase (RTK)-->Ras-->mitogen activated protein kinase (MAPK) cascade and one that involves a LIN-12/Notch family receptor. In this review, we first discuss how genetic strategies are being used to identify and analyze components that control vulval cell fate decisions. We then describe the different signaling systems that have been elucidated and how they relate to one another. Finally, we highlight several recently characterized genes that encode positive regulators, negative regulators or potential targets of the RTK-->Ras-->MAPK cascade involved in vulval induction.

Availability of liposomes as drug carriers to the brain

Phospholipid vesicles, also known as liposomes, were examined for their ability to act as a drug carrier to the brain. 9-Amino-1,2,3,4-tetrahydroacridine (THA), a centrally acting acetylcholinesterase inhibitor, was used as a model drug. THA was encapsulated in dehydration-rehydration vesicles (DRV) composed of egg yolk phosphatidylcholine, cholesterol and dipalmitoyl-phosphatidic acid (molar ratio, 10/10/1) and injected into the heart of mice. The toxicity and side effects of THA were reduced by encapsulation in liposomes. The THA concentration in the mouse brain after injection of THA-encapsulated DRV at a dose of 2 mg/kg remained higher than that of free THA at the same dose. Effective concentration of THA in the brain was also prolonged by the use of liposomes, although accumulation of THA in the spleen and kidney was observed. We, therefore, concluded that liposomes are useful as carriers of drugs to the brain.

The effects of acute and chronic exercise on sleep. A meta-analytic review

Studies attempting to ascertain the effects of acute and chronic exercise on measures of sleep have yielded conflicting results and interpretations. Methodological differences among studies may explain this lack of consensus; however, small sample sizes and subsequently low statistical power may also have contributed. In an attempt to resolve these issues, this review used meta-analytical techniques to: (a) re-examine the effects of exercise on sleep; and (b) examine possible moderators of these effects. Studies meeting the selection criteria were included in the analysis. Analyses of moderating factors were performed for stage 4 sleep and rapid eye movement (REM) sleep. The results indicated that acute and chronic exercise increased slow wave sleep (SWS) and total sleep time but decreased sleep onset latency and REM sleep. Moderating variables influencing the magnitude and direction of these effects were related to characteristics of the individual (e.g. sex, age, fitness level) and the exercise (e.g. time of day exercise was completed, type of exercise, exercise duration). Mechanisms which have been suggested to explain the relationship between exercise and sleep are discussed and directions for further research are provided.

The C. elegans ksr-1 gene encodes a novel Raf-related kinase involved in Ras-mediated signal transduction

Vulval induction in C. elegans is controlled by a highly conserved signaling pathway similar to the RTK-Ras-MAPK cascade in mammals. By screening for suppressors of the Multivulva phenotype caused by an activated let-60 ras allele, we isolated mutations in a gene, ksr-1, that acts as a positive modifier of vulval induction and is required for at least two other let-60 ras-mediated processes. Although ksr-1 mutations do not perturb vulval induction in an otherwise wild-type background, they have very strong effects on vulval induction in genetic backgrounds where Ras pathway activity is constitutively activated or compromised, suggesting that ksr-1 activity is required for maximal stimulation of vulval fates by the Ras pathway. Genetic epistasis analysis suggests that ksr-1 acts downstream of or in parallel to let-60 ras. We cloned ksr-1 and have shown that it encodes a novel putative protein kinase related to the Raf family of Ser/Thr kinases.

Neurosteroid analogues. 3. The synthesis and electrophysiological evaluation of benz[e]indene congeners of neuroactive steroids having the 5 beta-configuration

A series of 7-(2-hydroxyethyl)benz[e]indene analogues of 3 alpha-hydroxy-5 beta-pregnan-20-one (7), a neuroactive steroid known to be a positive allosteric modulator of GABAA receptor function, was prepared. Electrophysiological measurements carried out on cultured rat hippocampal neurons were used to evaluate the modulatory effects of the analogues on GABAA receptor function. Analogues were tested for their ability to potentiate 1 microM GABA-mediated chloride currents and for their ability to directly gate chloride currents at this ligand-gated ion channel. Active analogues typically enhanced GABA-mediated currents at concentrations below those required to directly gate chloride currents. The dose-response relationships for potentiation of 1 microM GABA-mediated chloride currents were studied for [3S-(3 alpha, 3a alpha, 5a beta, 7 beta, 9a alpha, 9b beta)]-1- [dodecahydro-7-(2-hydroxyethyl)-3a-methyl-1H-benz[e]inden-3- yl]ethanone (3), steroid 7, 3 alpha-hydroxy-5 alpha-pregnan-20-one (5), and the analogous 7 alpha-(2-hydroxyethyl)benz[e]indene analogue of steroid 5 (compound 1). Compound 3 was the most active potentiator (EC50 = 0.017 microM) of GABA-mediated current. The direct gating actions of compound 3 were not observed at a concentration of 1 microM, but were observed at a concentration of 10 microM.

sur-2, a novel gene, functions late in the let-60 ras-mediated signaling pathway during Caenorhabditis elegans vulval induction

We describe here a new gene acting downstream of let-60 ras in the vulval signaling pathway of Caenorhabditis elegans. The sur-2 (suppressor of ras) gene is defined by eight mutations identified in a genetic screen for suppressors of the Multivulva phenotype of let-60(n1046), an activated let-60 ras mutation. sur-2 mutations result in pleiotropic, incompletely penetrant phenotypes that include a Vulvaless phenotype in hermaphrodites, defects in development of the male tail, gonadal abnormalities, and larval lethality, indicating a role for the sur-2 gene product in multiple developmental events. Genetic epistasis analyses suggest that sur-2 is required late in the vulval signaling pathway, downstream of let-60 Ras, and is likely to act downstream of the Raf/MAP Kinase cascade. We cloned the sur-2 gene by DNA-mediated transformation and have shown that it encodes a novel protein. We also show that a sur-2::lacZ transgene is expressed in the vulval precursor cells at the time of vulval determination.

High-resolution structural studies of the retinal--Glu113 interaction in rhodopsin

The key to understanding the reaction mechanism of rhodopsin lies in determining the structure of the retinal binding site and in defining the charge interactions between Glu113 and the retinal protonated Schiff base chromophore. We have been using 13C-NMR chemical shift data to determine the location of the Glu113 carboxyl side chain in relation to the retinal. The NMR data constrain one of the carboxylate oxygens of Glu113 to be ca. 3 A from the C12 position of the retinal with the second oxygen oriented away from the conjugated chain. A water molecule forming a hydrogen bond with the Schiff base is incorporated into the model to account for the high C = N stretching frequency [Han et al., Biophys. J., 65 (1993) 899]. In this study, we have refined the counterion position and have shown that it can reproduce the observed chemical shift data as well as the red-shifted absorption maximum of rhodopsin. Furthermore, the retinal binding site geometry derived from the NMR constraints can be readily incorporated into a recent structural model of the apoprotein.

Ras farnesyltransferase inhibitors suppress the phenotype resulting from an activated ras mutation in Caenorhabditis elegans

Attachment of Ras protein to the membrane, which requires farnesylation at its C terminus, is essential for its biological activity. A promising pharmacological approach of antagonizing oncogenic Ras activity is to develop inhibitors of farnesyltransferase. We use Caenorhabditis elegans vulval differentiation, which is controlled by a Ras-mediated signal transduction pathway, as a model system to test previously identified farnesyltransferase inhibitors. We show here that two farnesyltransferase inhibitors, manumycin and gliotoxin, suppress the Multivulva phenotype resulting from an activated let-60 ras mutation, but not the Multivulva phenotype resulting from mutations in the lin-1 gene or the lin-15 gene, which act downstream and upstream of let-60 ras, respectively, in the signaling pathway. These results are consistent with the idea that the suppression of the Multivulva phenotype of let-60 ras by the two inhibitors is specific for Ras protein and that the mutant Ras protein might be more sensitive than wild-type Ras to the farnesyltransferase inhibitors. This work suggests that C. elegans vulval development could be a simple and effective in vivo system for evaluation of farnesyltransferase inhibitors against Ras-activated tumors.