Magnolol, a major bioactive constituent of the bark of Magnolia officinalis, induces sleep via the benzodiazepine site of GABA(A) receptor in mice

Magnolol (6,6',7,12-tetramethoxy-2,2'-dimethyl-1-beta-berbaman, C(18)H(18)O(2)), an active ingredient of the bark of Magnolia officinalis, has been reported to exert potent anti-epileptic effects via the GABA(A) receptor. The receptor also mediates sleep in humans and animals. The aim of this study was to determine whether magnolol could modulate sleep behaviors by recording EEG and electromyogram in mice. The results showed that magnolol administered i.p. at a dose of 5 or 25 mg/kg could significantly shorten the sleep latency, increase the amount of non-rapid eye movement (non-REM, NREM) and rapid eye movement (REM) sleep for 3 h after administration with an increase in the number of NREM and REM sleep episodes. Magnolol at doses of 5 and 25 mg/kg increased the number of bouts of wakefulness but decreased their duration. On the other hand, magnolol increased the number of state transitions from wakefulness to NREM sleep and subsequently from NREM sleep to wakefulness. Immunohistochemical study showed that magnolol increased c-Fos expression in the neurons of ventrolateral preoptic area, a sleep center in the anterior hypothalamus, and decreased c-Fos expression in the arousal tuberomammillary nucleus, which was located in the caudolateral hypothalamus. The sleep-promoting effects and changes in c-Fos induced by magnolol were reversed by flumazenil, an antagonist at the benzodiazepine site of the GABA(A) receptor. These results indicate that magnolol increased NREM and REM sleep via the GABA(A) receptor.

Difficulties in organ procurement and transplantation in the aboriginal minority people in Taiwan

BACKGROUND

Aboriginal people (AP) are a minority group in Taiwan. Little information on their perspectives on organ transplantation (OT) is available. Their rights for organ donation (OD) and as OT recipients (OTR) are constrained as a vulnerable population in society. This research sought to explore various Highland Aborigine Tribes beliefs systems and concepts related to OT.

METHODS

We employed a qualitative design on a purposive sample including seven categories of Taiwanese AP. Data collected by face-to-face interviews were evaluated by content analysis.

RESULTS

Seventy-five informants (45 female and 30 males) of 18 to 82 years from seven tribes completed interviews: Bunun (n = 20), Shao (n = 18), Tsou (n = 15), Amis (n = 12), Truku (n = 4), Rukai (n = 3), and Puyuma (n = 3). Of there, 33% had no idea of OT. All informants reported lack of knowledge of OD, organ procurement, and OTR. Eighty percent (45-82 years) had no willingness for OD or OTR; others might consult family members and health professionals (HP) to learn about OT. Seven hindering factors were identified: (1) having no background of OT; (2) limited impressions obtained from television news reports; (3) negative concepts of donating one's organs to others; (4) OT concepts contrast with cultural meanings of death; (5) possibility of being stigmatized; (6) fear of being rejected by others; and (7) HP had never mentioned OT.

CONCLUSIONS

Taiwan APs' perspectives of OT concepts showed the majority to be unfamiliar with the concept and benefits of OT. Future research is necessary to explore the possible avenues to facilitate communications between HP and AP leaders, as well as elders in each AP category in Taiwan.

Magnolol, a major bioactive constituent of the bark of Magnolia officinalis, exerts antiepileptic effects via the GABA/benzodiazepine receptor complex in mice

BACKGROUND AND PURPOSE

The aim of this study was to evaluate the anti-convulsant effects of magnolol (6, 6', 7, 12-tetramethoxy-2, 2'-dimethyl-1-β-berbaman, C18H18O2) and the mechanisms involved.

EXPERIMENTAL APPROACH

Mice were treated with magnolol (20, 40 and 80 mg·kg(-1)) 30 min before injection with pentylenetetrazol (PTZ, 60 mg·kg(-1), i.p.). The anti-seizure effects of magnolol were analysed using seizure models of behaviour, EEG and in vitro electrophysiology and c-Fos expression in the hippocampus and cortex.

KEY RESULTS

Magnolol at doses of 40 and 80 mg·kg(-1) significantly delayed the onset of myoclonic jerks and generalized clonic seizures, and decreased the seizure stage and mortality compared with those of the vehicle-treated animals. EEG recordings showed that magnolol (40 and 80 mg·kg(-1)) prolonged the latency of seizure onset and decreased the number of seizure spikes. The anti-epileptic effect of magnolol was reversed by the GABA(A)/benzodiazepine receptor antagonist flumazenil. Pretreatment with flumazenil decreased the effects of magnolol on prolongation of seizure latency and decline of seizure stage. In a Mg(2+)-free model of epileptiform activity, using multi-electrode array recordings in mouse hippocampal slices, magnolol decreased spontaneous epileptiform discharges. Magnolol also significantly decreased seizure-induced Fos immunoreactivity in the piriform cortex, dentate gyrus and hippocampal area CA1. These effects were attenuated by pretreatment with flumazenil.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that the inhibitory effects of magnolol on epileptiform activity were mediated by the GABA(A) /benzodiazepine receptor complex.

Expression and significance of lipin1 and AMPKα in hepatic insulin resistance in diet-induced insulin resistance rats

BACKGROUND

Lipin1, a lately indentified adipokine, may link obesity with insulin resistance and diabetes. The present study aimed to investigate the changes and significance of lipin1 expression and lipin1-AMPK signaling in diet-induced hepatic insulin resistance.

METHODS

24 4-week-old Male Wistar rats were randomly divided into 2 groups: (1) control group (CO), (2) high-fat diet group (HF). Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. The mRNA levels of α1 and α2 subunit of AMPKα as well as Lipin1 were measured using Real-time RT-PCR. The activities of AMPKα and Akt were evaluated by detection of p-AMPKα (Thr-172) and p-Akt (ser473) by Western blot.

RESULTS

After treatment of 4 months, HF group showed significantly increased levels of body weight, fasting plasma glucose and insulin levels; Plasma and liver total cholesterol (TC), triglycerides (TG) levels were also markedly elevated; Lipin1 expression at both mRNA and protein levels were significantly deceased. Compared with CO group, the mRNA and protein levels of AMPKα1 and AMPKα2 were not changed, whereas the p-AMPK (Thr-172) and p-AKT (ser473) levels in liver were significantly decreased in HF group.

CONCLUSIONS

These findings indicated that the decrease in lipin1 expression and AMPKα activation may contribute to hepatic insulin resistance in diet-induced obese rats.

Behaviour and dynamics of di-ammonium phosphate in bauxite processing residue sand in Western Australia--I. NH3 volatilisation and residual nitrogen availability

BACKGROUND, AIM AND SCOPE

Australia is the largest producer of bauxite in the world, with an annual output of approximately 62 million metric dry tons in 2007. For every tonne of alumina, about 2 tonnes of highly alkaline and highly saline bauxite-processing residue are produced. In Western Australia, Alcoa World Alumina, Australia (Alcoa) produces approximately 15 MT of residue annually from its refineries (Kwinana, Pinjarra and Wagerup). The bauxite-processing residue sand (BRS) fraction represents the primary material for rehabilitating Alcoa's residue disposal areas (RDAs). However, the inherently hostile characteristics (high alkalinity, high salinity and poor nutrient availability) of BRS pose severe limitations for establishing sustainable plant cover systems. Alcoa currently applies 2.7 t ha(-1) of di-ammonium phosphate ((NH(4))(2)HPO(4); DAP)-based fertiliser as a part of rehabilitation of the outer residue sand embankments of its RDAs. Limited information on the behaviour of the dominant components of this inorganic fertiliser in highly alkaline BRS is currently available, despite the known effects of pH on ammonium (NH(4)) and phosphorus (P) behaviour. The aim of this study was to quantify the effects of pH on NH(3) volatilisation and residual nitrogen (N) in BRS following DAP applications.

METHODS

The sponge-trapping and KCl-extraction method was used for determining NH(3) volatilisation from surface-applied DAP in samples of BRS collected from each of Alcoa's three Western Australia Refineries (Kwinana, Pinjarra, Wagerup) under various pH conditions (pH 4, 7, 9 and 11). Following cessation of volatilisation, the residual N was extracted from BRS using 2 M KCl and concentrations of NH (4) (+) -N and NO (3) (-) -N were determined by flow injection analysis.

RESULTS

The quantities of NH(3) volatilised increased dramatically as the pH increased from 4 to 11. Much of the N lost as NH(3) (up to 95.2%) occurred within a short period (24 h to 7 days), particularly for the pH 9 and 11 treatments. Concentrations of residual NH (4) (+) -N recovered in DAP-treated BRS at the end of the experiment decreased with increasing pH. This finding was consistent with increasing loss of N via volatilisation as pH increased. The concentration of NO (3) (-) -N was very low due to no nitrification in BRS.

DISCUSSION

The pH was a key driver for NH(3) volatilisation from DAP-treated BRS and primarily controlled N dynamics in BRS. Results indicate that NH(4) not adsorbed by BRS was highly susceptible to volatilisation. The likely lack of nitrifying bacteria did not allow conversion of ammonium to nitrate, thereby further exacerbating the potential for loss via volatilisation

CONCLUSIONS

It was demonstrated that the pH is the key factor controlling the loss of inorganic N from BRS. Although volatilisation was considerably lower at pH 4, achieving this pH reduction in the field is not possible at present. Findings from this study highlight the need to better understand which forms of N fertiliser are most suitable for use in highly alkaline BRS.

RECOMMENDATION AND PERSPECTIVES

Although pH reduction is the most likely means of stopping NH(3) volatilisation in BRS, it is economically and operationally unfeasible to add sufficient acidity for adequately lowering pH in the BRS for revegetation. More attention on forms of fertilisers more suitable to highly alkaline, microbially inert soil conditions appears to be warranted.

Behaviour and dynamics of di-ammonium phosphate in bauxite processing residue sand in Western Australia--II. Phosphorus fractions and availability

BACKGROUND, AIM AND SCOPE

The production of alumina involves its extraction from bauxite ore using sodium hydroxide under high temperature and pressure. This process yields a large amount of residue wastes, which are difficult to revegetate due to their inherent hostile properties--high alkalinity and sodicity, poor water retention and low nutrient availability. Although phosphorus (P) is a key element limiting successful ecosystem restoration, little information is available on the availability and dynamics of P in rehabilitated bauxite-processing residue sand (BRS). The major aim of this experiment was to quantify P availability and behaviour as affected by pH, source of BRS and di-ammonium phosphate (DAP) application rate.

MATERIALS AND METHODS

This incubation experiment was undertaken using three sources of BRS, three DAP application rates (low, without addition of DAP; medium, 15.07 mg P and 13.63 mg N of DAP per jar, 100 g BRS; and high, 30.15 mg P and 27.26 mg N per jar, 100 g BRS), and four BRS pH treatments (4, 7, 9 and 11 (original)). The moisture content was adjusted to 55% water holding capacity and each BRS sample was incubated at 25 degrees C for a period of 119 days. After this period, Colwell P and 0.1 M H(2)SO(4) extractable P in BRS were determined. In addition, P sequential fractionation was carried out and the concentration of P in each pool was measured.

RESULTS AND DISCUSSION

A significant proportion (37% recovered in Colwell P and 48% in 0.1 M H(2)SO(4) extraction) of P added as DAP in BRS are available for plant use. The pH did not significantly affect 0.1 M H(2)SO(4) extractable P, while concentrations of Colwell P in the higher initial pH treatments (pH 7, 9 and 11) were greater than in the pH 4 treatments. The labile fractions (sum of NH(4)Cl (AP), bicarbonate and first sodium hydroxide extractable P (N(I)P)) consisted of 58-64% and 70-72% of total P in the medium and high DAP rate treatments, respectively. This indicates that most P added as DAP remained labile or moderately labile in BRS, either in solution, or in adsorbed forms on the surface of more crystalline P compounds, sesquioxides and carbonate, or associated with amorphous and some crystalline Al and Fe hydrous oxides. In addition, differences in the hydrochloric acid extractable P and the residual-P fractions among the treatments with and without DAP addition were relative small comparing with other P pools (e.g., NaOH extractable P pools), further indicating the limited capacity of BRS for fixing P added in Ca-P and other most recalcitrant forms.

CONCLUSIONS

P availability in the original BRS without addition of DAP was very low, mostly in recalcitrant form. It has been clearly demonstrated that significant proportions of P added as DAP could remain labile or moderately labile for plant use during the rehabilitation of bauxite-processing residue disposal areas. There was limited capacity of BRS for fixing P in more recalcitrant forms (e.g., Ca-P and residual-P). Concentrations of most P pools in BRS increased with the DAP application rate. The impact of the pH treatment on P availability varied with the type of P pools and the DAP rate.

RECOMMENDATION AND PERSPECTIVES

It is recommended that the development of appropriate techniques for more accurate estimation of P availability in BRS and the quantification of the potential leaching loss of P in BRS are needed for the accurate understanding of P availability and dynamics in BRS. In addition, application of organic matters (e.g., biosolids and biochar, etc.) to BRS may be considered for improving P availability and buffering capacity.

Anti-osteosarcoma effects and mechanisms of 4-O-amino-phenol-4‘-demethylepipodophyllotoxin ether

The purpose of this study was to investigate the anti-osteosarcoma effects and mechanisms of 4-O-amino-phenol-4′-demethylepipodophyllotoxin ether (ODE), a new derivative of podophyllotoxin. The results showed that ODE inhibited proliferation of K562, OS-9901, CNE, BGC-823 and Tca-8113 cells in a time- and concentration-dependent manner as determined by microculture tetrazolium (MTT) assay. OS-9901 and K562 cells treated with ODE for 24h showed cell cycle arrest at G2/M and a parallel decrease in G0/G1 and S phase as detected by flow cytometry (FCM). Meanwhile, a fraction of cells with hypodiploid DNA content representing apoptosis were detected by FCM. Morphology observation also revealed typical apoptotic features, including shrinkage of cellular and nuclear membranes, condensed heterochromatin around the nuclear periphery and cytoplasmic vacuolation in OS-9901 cells. Under a confocal laser scanning microscope, intracellular Ca2+ and Mg2+ concentrations were greatly increased whereas the pH value, mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) were markedly reduced in OS-9901 cells after treatment with ODE. Taken together, these results suggest that the anti-osteosarcoma mechanisms of ODE are attributed to apoptosis through increasing intracellular Ca2+ and Mg2+ concentrations, and reducing pH value, MMP and ROS.

A controllable double-well magneto-optical trap for Rb and Cs atoms

We experimentally demonstrate a novel scheme to simultaneously confine two atomic species of (87)Rb and (133)Cs with adjustable spatial separation by a controllable double-well magneto-optic trap. Using a single-loop wire and a magnetic bias field, the two clouds, each containing more than 1 x 10(6) atoms, are spatially separated above and below the wire center of the double-well MOT. The cloud interdistance can be controlled by independently varying the wire current and external bias field. This allows to load the double-well magnetic trap, and to study the dynamics of cold collisions between two-species atoms.

Modafinil exerts a dose-dependent antiepileptic effect mediated by adrenergic α1 and histaminergic H1 receptors in mice

Epilepsy is characterized by neuronal hyperexcitability and hypersynchronization. Disruption of electroencephalographically (EEG) synchronized epileptiform discharges may be a possible therapy for epilepsy. In the present study, to clarify the role of EEG desynchronization on epilepsy, we investigated the effect of modafinil, a potent wake-promoting substance with EEG desynchronization activity, on epilepsy in mice and clarified the receptors involved in the suppression of seizure caused by maximal electroshock (MES) and pentylenetetrazol (PTZ) kindling models. Modafinil given at 22.5, 45, and 90 mg/kg, i.p. significantly decreased the incidence of tonic hindleg extension in MES seizure models, and protected against PTZ-induced convulsive behaviors in a dose-dependent manner. In addition, modafinil at 180 mg/kg exerted an antiepileptic effect in the MES model; however, at the same dosage it increased the seizure stage in the PTZ-kindling model. The antiepileptic effect in both MES and PTZ models was antagonized by the adrenergic alpha(1) receptor antagonist terazosin, but not by the adrenergic alpha(2) receptor antagonist yohimbine or by dopaminergic receptor antagonists, SCH-23390 (for D(1) receptors) and haloperidol (for D(2) ones). Pyrilamine, a histaminergic H(1) receptor antagonist, counteracted the antiepileptic action of modafinil in the PTZ induced-kindling model, but not in the MES seizure model. Taken together, the present findings indicate that modafinil exerted its antiepileptic effect via adrenergic alpha(1) and histaminergic H(1) receptors, and might be of potential use in the treatment of epilepsy.

Characteristics of hydroxyapatite coated titanium porous coatings on Ti-6Al-4V substrates by plasma sprayed method

A porous metal coating applied to solid substrate implants has been shown, in vivo, to anchor implants by bone ingrowth. Calcium phosphate ceramics, in particular hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2), HA], are bioactive ceramics, which are known to be biocompatible and osteoconductive, and these ceramics deposited on to porous-coated devices may enhance bone ingrowth and implant fixation. In this study, bi-feedstock of the titanium powder and composite (Na(2)CO(3)/HA) powder were simultaneously deposited on a Ti-6Al-4V substrate by a plasma sprayed method. At high temperature of plasma torch, the solid state of Na(2)CO(3) would decompose to release CO(2) gas and then eject the molten Ti powder to induce the interconnected pores in the coatings. After cleaning and soaking in deionized water, the residual Na(2)CO(3) in the coating would dissolve to form the open pores, and the HA would exist at the surface of pores in the inner coatings. By varying the particle size of the composite powder, the porosity of porous coating could be varied from 25.0 to 34.0%, and the average pore size of the porous coating could be varied to range between 158.5 and 202.0 microm. Using a standard adhesive test (ASTM C-633), the bonding strength of the coating is between 27.3 and 38.2 MPa. By SEM, the HA was observed at the surface of inner pore in the porous coating. These results suggest that the method exhibits the potential to manufacture the bioactive ceramics on to porous-coated specimen to achieve bone ingrowth fixation for biomedical applications.

Radiation safety impact for top-up operation at the NSRRC

Radiation safety impact for the upcoming top-up operation at the National Synchrotron Radiation Research Center (NSRRC) has been investigated with emphasis on the consequence of injection efficiency. Keeping the storage ring at high stored current by frequent injections, the top-up operation will inevitably increase the radiation dose compared with that in the present decay mode, especially when the injection efficiency is low. In addition, significantly high level of radiation could stream through the ratchet wall openings during top-up injections while shutters are open. Therefore, a series of radiation safety analyses including calculations and measurements have been carried out to assess the feasibility of this mode on the prospective radiation protection. The paper summarises the evaluation and the corresponding action plans for radiation safety.

Network-based real-time radiation monitoring system in Synchrotron Radiation Research Center

The real-time radiation monitoring system (RMS) in the Synchrotron Radiation Research Center (SRRC) has been upgraded significantly during the past years. The new framework of the RMS is built on the popular network technology, including Ethernet hardware connections and Web-based software interfaces. It features virtually no distance limitations, flexible and scalable equipment connections, faster response time, remote diagnosis, easy maintenance, as well as many graphic user interface software tools. This paper briefly describes the radiation environment in SRRC and presents the system configuration, basic functions, and some operational results of this real-time RMS. Besides the control of radiation exposures, it has been demonstrated that a variety of valuable information or correlations could be extracted from the measured radiation levels delivered by the RMS, including the changes of operating conditions, beam loss pattern, radiation skyshine, and so on. The real-time RMS can be conveniently accessed either using the dedicated client program or World Wide Web interface. The address of the Web site is http:// www-rms.srrc.gov.tw.

Volatile Fingerprinting (SPME-GC-FID) to Detect and Discriminate Diseases of Potato Tubers

Volatiles from Russet Burbank potatoes inoculated with Erwinia carotovora subsp. carotovora, E. carotovora subsp. atroseptica, Pythium ultimum, Phytophthora infestans, or Fusarium sambucinum were monitored by sampling the head space 3, 4, and 5 days after inoculation, using a solid phase microextraction (SPME) fiber to trap and gas chromatography with flame ionization detector (GC-FID) to fingerprint volatiles. Noninoculated (NON) potatoes served as the control. Volatile fingerprints varied among diseases. Within a disease, the fingerprints varied with time since inoculation and among blocks. In general, more volatiles were observed on the fourth and fifth day after inoculation than on the third day. The amount of volatile compounds produced (peak area) within a disease group increased with incubation time; however, the variation among blocks was much higher. The amount of volatiles produced, in general, was associated with disease severity. Disease-specific volatiles were observed. The F. sambucinum chromatogram had two unique peaks at retention time (RT) = 14.1 and 17.3 min. P. infestans produced few peaks and the profile was quite similar to NON. In contrast, E. carotovora subsp. carotovora, E. carotovora subsp. atroseptica, and Pythium ultimum produced many peaks, and the P. ultimum was different from the bacteria, in that the chromatogram peaks at RT = 4.04 and 8.76 min were absent. Instead, it produced a distinct peak at RT = 1.71 min. E. carotovora subsp. carotovora and E. carotovora subsp. atroseptica couldn't be discriminated based on unique peaks; however, they varied in concentration of volatiles produced. E. carotovora subsp. carotovora produced more of RT = 2.0 min and less of RT = 2.3 and 2.44 min than E. carotovora subsp. atroseptica. A back-propagation network (using neural networks) was developed to classify volatile profiles into six disease-groups. Cross-validation classification probabilities were NON = 71, E. carotovora subsp. carotovora = 71, E. carotovora subsp. atroseptica = 71, P. ultimum = 67, Phytophthora infestans = 46, and F. sambucinum = 75%.

Arachidonic acid-induced H+ and Ca2+ increases in both the cytoplasm and nucleoplasm of rat cerebellar granule cells

1. Arachidonic acid (AA) exerts multiple physiological and pathophysiological effects in the brain. By continuously measuring the intracellular pH (pH(i)) and Ca2+ levels ([Ca2+]i) in primary cultured rat cerebellar granule cells, we have found, for the first time, that 20 min treatment with 10 microM AA resulted in marked increases in Ca2+ and H+ levels in both the cytosol and nucleus. 2. A much higher concentration (40 mM) of another weak acid, propionic acid, was needed to induce a similar change in pH(i). The [Ca2+]i increase was probably caused by AA-induced activation of Ni2+-sensitive cationic channels, but did not involve NMDA channels or the Na+-Ca2+ exchanger. 3. AA-induced acidosis occurs by a different mechanism involving predominantly the passive diffusion of the un-ionized form of AA, rather than a protein carrier, as proposed by Kamp & Hamilton for fatty acids (FAs) in artificial phospholipid bilayers (the 'flip-flop' model). The following results, which are similar to those observed in lipid bilayers, support this conclusion: (1) FAs containing a -COOH group (AA, linoleic acid, alpha-linolenic acid, and docosahexaenoic acid) induced intracellular acidosis, whereas a FA with a -COOCH3 group (AA methyl ester) had little effect on pH(i), (2) a FA amine, tetradecylamine, induced intracellular alkalosis, and (3) the AA-/FA-induced pH(i) changes were reversed by bovine serum albumin. 4. Further evidence in support of a passive diffusion model, rather than a membrane protein carrier, is that: (1) there was a linear relationship between the initial rate of acid flux and the concentration of AA (2-100 microM), (2) acidosis was not inhibited by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid, a potent inhibitor of the plasma membrane FA carrier protein, and (3) the involvement of most known H+-related membrane carriers and H+ conductance has been ruled out. 5. Since AA can be released under both physiological and pathophysiological conditions, the possible significance of the AA-evoked increases in H+ and Ca2+ in both the cytoplasm and nucleoplasm is discussed.

A full biological response to autoantibodies in Graves' disease requires a disulfide-bonded loop in the thyrotropin receptor N terminus homologous to a laminin epidermal growth factor-like domain

We observed amino acid homology between the cysteine-rich N terminus of the thyrotropin receptor (TSHR) ectodomain and epidermal growth factor-like repeats in the laminin gamma1 chain. Thyroid-stimulating autoantibodies (TSAb), the cause of Graves' disease, interact with this region of the TSHR in a manner critically dependent on antigen conformation. We studied the role of the cluster of four cysteine (Cys) residues in this region of the TSHR on the functional response to TSAb in Graves' patients' sera. As a benchmark we also studied TSH binding and action. Removal in various permutations of the four cysteines at TSHR positions 24, 29, 31, and 41 (signal peptide residues are 1-21) revealed Cys(41) to be the key residue for receptor expression. Forced pairing of Cys(41) with any one of the three upstream Cys residues was necessary for trafficking to the cell surface of a TSHR with high affinity TSH binding similar to the wild-type receptor. However, for a full biological response to TSAb, forced pairing of Cys(41) with Cys(29) or with Cys(31), but not with Cys(24), retained functional activity comparable with the wild-type TSHR. These data suggest that an N-terminal disulfide-bonded loop between Cys(41) and Cys(29) or its close neighbor Cys(31) comprises, in part, the highly conformational epitope for TSAb at the critical N terminus of the TSHR. Amino acid homology, as well as cysteine pairing similar to the laminin gamma1 chain epidermal growth factor-like repeat 11, suggests conformational similarity between the two molecules and raises the possibility of molecular mimicry in the pathogenesis of Graves' disease.

Insight into thyrotropin receptor cleavage by engineering the single polypeptide chain luteinizing hormone receptor into a cleaving, two subunit receptor

To gain insight into the thyrotropin hormone (TSH) receptor (TSHR) cleavage, we sought to convert the noncleaving luteinizing hormone (LH) receptor (LHR) into a cleaved, two-subunit molecule. For this purpose, we generated a series of LHR mutants and chimeric LH-TSH receptors. Cleavage of mature, ligand binding receptors on the cell surface was determined by covalent 125I-labeled hCG crosslinking to intact, stably transfected mammalian cells. We first targeted a cluster of three N-linked glycans in the LHR (N295, N303, N317) in a region corresponding to the primary TSHR cleavage site, which has only one N-linked glycan. Elimination by mutagenesis of the most strategic N-linked glycan (LHR-N317Q) generated only a trace amount of LHR cleavage. Removal of the other N-linked glycans had no additive effect. A much greater degree of cleavage ( approximately 50%) was evident in a chimeric LH-TSHR in which the juxtamembrane segment of the LHR (domain E; amino acids 317-367) was replaced with the corresponding domain of the TSHR (residues 363-418). Similarly cleaving LHR were created using a much smaller component within this region, namely LHR-NET317-319 replaced with TSHR-GQE367-369, or by substitution of the same three amino-acid residues with AAA (LHR-NET317-319AAA). In summary, our data alter current concepts regarding TSHR cleavage by suggesting limited (not absent) amino-acid specificity in a region important for TSHR cleavage (GQE367-369). The data also support the concept of a separate and distinct downstream cleavage site 2 in the TSHR.

Defective repression of c-myc in breast cancer cells: A loss at the core of the transforming growth factor beta growth arrest program

Loss of growth inhibitory responses to the cytokine transforming growth factor beta (TGF-beta) in cancer cells may result from mutational inactivation of TGF-beta receptors or their signal transducers, the Smad transcription factors. In breast cancer, however, loss of TGF-beta growth inhibition often occurs without a loss of these signaling components. A genome-wide analysis of rapid TGF-beta gene responses in MCF-10A human mammary epithelial cells and MDA-MB-231 breast cancer cells shows that c-myc repression, a response that is key to the TGF-beta program of cell cycle arrest, is selectively lost in the cancer cell line. Transformation of MCF-10A cells with c-Ha-ras and c-erbB2 oncogenes also led to a selective loss of c-myc repression and cell cycle arrest response. TGF-beta stimulation of epithelial cells rapidly induces the formation of a Smad complex that specifically recognizes a TGF-beta inhibitory element in the c-myc promoter. Formation of this complex is deficient in the oncogenically transformed breast cells. These results suggest that a Smad complex that specifically mediates c-myc repression is a target of oncogenic signals in breast cancer.

Risk factors for uterine fibroids among women undergoing tubal sterilization

Uterine leiomyomas are reported to be the most common benign gynecologic tumors affecting premenopausal women, and they are often associated with considerable morbidity. The purpose of this study was to identify risk factors for uterine fibroids among women undergoing tubal sterilization. Cases comprised women aged 17-44 years whose uterine fibroids were first visualized at the time of tubal sterilization (1978-1979 or 1985-1987) or who reported a history of uterine fibroids (n = 317). Controls were randomly selected from women with no laparoscopic evidence of or history of fibroids (n = 1,268). Adjusted odds ratios were estimated using unconditional logistic regression separately for White (n = 1,235) and African-American (n = 350) women. Risk factors for White women included: age 40-44 years (odds ratio (OR) = 6.3; 95% confidence interval (CI): 3.5, 11.6), > or =5 years since last delivery (OR = 1.9; 95% CI: 1.1, 3.1), lifetime cigarette smoking of > or =1 pack/day (OR = 1.6; 95% CI: 1.1, 2.3), menstrual cycle length of >30 days (OR = 1.6; 95% CI: 1.1, 3.3), and menstrual bleeding for > or =6 days (OR = 1.4; 95% CI: 1.0, 2.0). Parous women were at reduced risk compared with nulliparous women (OR = 0.2; 95% CI: 0.1, 0.3). Advancing age was the only significant risk factor for African-American women (ages 40-44 years, OR = 27.5; 95% CI: 5.6, 83.6). Current oral contraceptive use and elective abortion were not associated with fibroids.

Genetic heterogeneity in familial juvenile polyposis

Juvenile polyposis syndrome (JPS) is an autosomal dominant syndrome characterized by multiple gastrointestinal hamartomatous polyps in the absence of the extraintestinal features that are classic for other hamartomatous polyposis syndromes, such as Bannayan-Riley-Ruvalcaba syndrome (BRRS) and Cowden disease (CD). About 50% of BRRS and >80% of CD demonstrate germ-line mutations in the tumor suppressor and dual phosphatase, PTEN. Germ-line mutation of PTEN as a cause for JPS in a child is controversial because extraintestinal manifestations that would exclude JPS could appear after adolescence, altering the clinical diagnosis. Here, we investigated a family in which the 55-year-old father, who lacks thyroid or skin findings characteristic of CD, demonstrated a germ-line mutation in PTEN that was passed to identical twin daughters, who both manifested JPS. The mutation was a deletion of five bases beginning seven bases from the start of exon 4 of PTEN, which caused aberrant transcripts by reverse transcription-PCR that were absent from a normal individual. Thus, mutations in PTEN are associated with JPS in addition to CD and some BRRS families, although the incidence of PTEN germ-line mutations in JPS might be more rare than that reported for SMAD4, a gene found to be mutated in approximately one-half of the JPS families investigated.

A conserved interaction between Moe1 and Mal3 is important for proper spindle formation in Schizosaccharomyces pombe

Moe1 is a conserved fission yeast protein that negatively affects microtubule stability/assembly. We conducted a two-hybrid screen to search for Moe1-binding proteins and isolated Mal3, a homologue of human EB1. We show that Moe1 and Mal3 expressed in bacteria form a complex and that Moe1 and Mal3 expressed in fission yeast cosediment with microtubules. Deletion of either moe1 or mal3 does not result in lethality; however, deletion of both moe1 and mal3 leads to cell death in the cold. The resulting cells appear to die of chromosome missegregation, which correlates with the presence of abnormal spindles. We investigated the cause for the formation of monopolar spindles and found that only one of the two spindle pole bodies (SPBs) contains gamma-tubulin, although both SPBs appear to be equal in size and properly inserted in the nuclear membrane. Moreover, the moe1 mal3 double null mutant in the cold contains abnormally short and abundant interphase microtubule bundles. These data suggest that Moe1 and Mal3 play a role in maintaining proper microtubule dynamics/integrity and distribution of gamma-tubulin to the SPBs during mitosis. Finally, we show that human Moe1 and EB1 can each rescue the phenotype of the moe1 mal3 double null mutant and form a complex, suggesting that these proteins are part of a well-conserved mechanism for regulating spindle functioning.

Fission yeast Ras1 effector Scd1 interacts with the spindle and affects its proper formation

Ras1 GTPase is the Schizosaccharomyces pombe homolog of the mammalian Ha-Ras proto-oncoprotein. Ras1 interacts with Scd1 (aka Ral1), a presumptive guanine nucleotide exchange factor for Cdc42sp, to control organization of the cytoskeleton. In this study, we demonstrated that the scd1 deletion (scd1Delta) induced hypersensitivity to microtubule destabilizing drugs and instability of the minichromosome. Overexpression of scd1 induced formation of abnormal spindles and chromosome missegregation. The scd1 deletion worsened the defects of spindle formation in tubulin mutants; by contrast, it did not induce lethality in mutants defective in the spindle pole bodies. These genetic data suggest that Scd1 can interact with tubulin with substantial specificity to affect proper spindle formation and chromosome segregation. Subcellular localization data further illustrated that a GFP-Scd1 fusion protein can associate with the spindle. Finally, we showed that unlike ras1Delta and scd1Delta, byr2Delta (affecting the Ras1 effector for mating) is not synthetically lethal with the tubulin mutations. These data collectively suggest that the Ras1 pathway can impinge upon microtubules through Scd1, but not Byr2, to affect proper spindle formation and chromosome segregation.

[A further research on physiopathological basis of "Liver Yang Forming Wind Syndrome"]

The multiple experimental parameters of different aspects in this study were determined in the patients with "Liver Yang Forming Wind Syndrome (LYFWS)", "Qi Deficiency Blood Stagnation Syndrome (QDBSS)" and "Yin Deficiency Forming Wind Syndrome (YDFWS)". The results showed that cerebral hemorrhage was similar to cerebral infarction in almost all parameters and the two diseases were with LYFWS. It was found that there were several characteristics in LYFWS, i.e. 1. Hyperfunction of sympathetic adrenal medullary system. 2. Hypotriiodothyroidoglobulin syndrome. 3. The marked changes of the active substance regulating vessel smooth muscle function. 4. The increased inflammatory medicators. The pathophysiological parameters in patients with QDBSS were the same as those with YDFWS, but the changes of QDBSS and YDFWS weRe milder than those of LYFWS.