Dyskinesias predict the onset of motor response fluctuations in patients with Parkinson's disease on L-dopa monotherapy

The aim of the study was to investigate the relationship between dyskinesias and motor fluctuations in patients with Parkinson's disease on l-dopa monotherapy. We identified 116 patients on l-dopa monotherapy treated between 1965 and 1992 and followed until death. Dyskinesias occurred in 102 patients. Of these, 48 only developed dyskinesias while 54 had both dyskinesias and motor fluctuations. Among patients with both complications, 49 developed dyskinesias before fluctuations, and only five had dyskinesias after the onset of fluctuations. Our findings suggest that dyskinesias predict the onset of motor fluctuations, and may share a common pathophysiological mechanism.

Flow of wet granular materials

The transition from frictional to lubricated flows of a dense suspension of non-Brownian particles is studied. The pertinent parameter characterizing this transition is the Leighton number Le=eta(s)gamma / sigma, the ratio of lubrication to frictional forces. Le defines a critical shear rate below which no steady flow without localization exists. In the frictional regime the shear flow is localized. The lubricated regime is not simply viscous: the ratio of shear to normal stresses remains constant and the velocity profile has a universal form in both frictional and lubricated regimes. Finally, a discrepancy between local and global measurements of viscosity is identified, which suggests inhomogeneity of the material under flow.

Incidence of dementia in a community-dwelling Brazilian population

The authors report the incidence of dementia in a community-dwelling Brazilian population. In 1997, 1656 individuals aged 65 years or more, the majority being of very low educational level, were screened at their homes in Catanduva, Brazil, and dementia was diagnosed in 118 cases. The remaining 1538 individuals were rescreened 3.25 years later applying a health questionnaire, the Mini-Mental State Examination (MMSE) and the Pfeffer Functional Activities Questionnaire (PFAQ). According to PFAQ and MMSE scores, selected subjects were submitted to clinical, neurologic, and cognitive evaluations. The subjects diagnosed with dementia underwent laboratory tests and brain computed tomography. A total of 1119 individuals were rescreened and 50 incident cases of dementia (28 with Alzheimer disease [AD]) were identified. The incidence rate of dementia was 13.8 and of AD was 7.7 per 1000 person-years for individuals aged 65 years or older. The incidence rates of dementia almost doubled with every 5 years of age. There was no difference according to gender, but women had a higher incidence of dementia, predominantly AD, in very old age. There was a trend for higher incidence of dementia in illiterates (p = 0.07), but multivariate analysis disclosed significant association only between age and higher incidence of dementia. The incidence rates of dementia in this Brazilian community are comparable to those reported in Western and Asian studies.

The effects of amorphous carbon films deposited on polyethylene terephthalate on bacterial adhesion

There is an increasing interest in developing new methods to reduce bacteria adhesion onto polymeric materials that are used in biomedical implants. The antibacterial behavior on polyethylene terephthalate (PET) treated by acetylene (C2H2) plasma immersion ion implantation-deposition (PIII-D) is investigated. The surface structure of the treated PET is determined by laser Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The results show that a thin amorphous polymer-like carbon (PLC) layer is formed on the PET surface. Atomic force micrographs (AFM) show that C2H2 PIII-D significantly changes the surface morphology of PET. The capacities of Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) to adhere onto PET are quantitatively determined by plate counting and Gamma-ray counting of 125I radio labeled bacteria in vitro. The results indicate that the adhesion of the two kinds of bacteria to PET is suppressed by PLC. The adhesion efficiency of SE on the coated surface is only about 14% of that of the untreated PET surface, and that of SA is about 35% of that of the virgin surface. The electrokinetic potentials of the bacterial cells and substrates are determined by zeta potential measurement. All the substrates as well as the bacterial strain have negative zeta potentials, and it means that bacterial adhesion is not mediated by electrostatic interactions. The surface energy components of the various substrates and bacteria are calculated based on measurements in water, formamide and diiodomethane. The surface free energies obtained are used to calculate the interfacial free energies of adhesion ( deltaFAdh ) of SA and SE onto various substrates, and it is found that bacterial adhesion is energetically unfavorable on the PLC deposited on PET by C2H2 PIII-D.

The Victorian Active Script Programme: promising signs for general practitioners, population health, and the promotion of physical activity

BACKGROUND

The Active Script Programme (ASP) aimed to increase the number of general practitioners (GPs) in Victoria, Australia who deliver appropriate, consistent, and effective advice on physical activity to patients. To maximise GP participation, a capacity building strategy within Divisions of General Practice (DGPs) was used. The objectives of the programme were to (a) train and support GPs in advising sedentary patients, and (b) develop tools and resources to assist GPs.

OBJECTIVE

To evaluate the effectiveness of the ASP.

METHODS

A systems approach was used to promote capacity in Victorian general practice. Economic analyses were incorporated into the programme's evaluation. Participants were selected DGPs and their GP members. The programme worked with DGPs to train GPs and provide relevant resources. The main outcome measures were (a) changes in GP knowledge and behaviour and (b) cost effectiveness, based on modelled estimates of numbers of patients advised and adopting physical activity and gaining the associated health benefits.

RESULTS

GP awareness and provision of physical activity advice increased. Although the programme's reach was modest, based on actual GP involvement, the cost effectiveness figures (138 Australian dollars per patient to become sufficiently active to gain health benefits, and 3647 Australian dollars per disability adjusted life year saved) are persuasive.

CONCLUSIONS

The ASP increased DGPs' capacity to support GPs to promote physical activity. There is a strong economic argument for governments to invest in such programmes. However, caution is warranted about the maintenance of patients' activity levels. Programme refinement to encourage GPs to use community supports more effectively will guide future development. Further research on long term patient adherence through a multisectorial approach is warranted.

QTL x environment interactions in rice. I. heading date and plant height

One hundred twenty six doubled-haploid (DH) rice lines were evaluated in nine diverse Asian environments to reveal the genetic basis of genotype x environment interactions (GEI) for plant height (PH) and heading date (HD). A subset of lines was also evaluated in four water-limited environments, where the environmental basis of G x E could be more precisely defined. Responses to the environments were resolved into individual QTL x environment interactions using replicated phenotyping and the mixed linear-model approach. A total of 37 main-effect QTLs and 29 epistatic QTLs were identified. On average, these QTLs were detectable in 56% of the environments. When detected in multiple environments, the main effects of most QTLs were consistent in direction but varied considerably in magnitude across environments. Some QTLs had opposite effects in different environments, particularly in water-limited environments, indicating that they responded to the environments differently. Inconsistent QTL detection across environments was due primarily to non- or weak-expression of the QTL, and in part to significant QTL x environment interaction effects in the opposite direction to QTL main effects, and to pronounced epistasis. QTL x environment interactions were trait- and gene-specific. The greater GEI for HD than for PH in rice were reflected by more environment-specific QTLs, greater frequency and magnitude of QTL x environment interaction effects, and more pronounced epistasis for HD than for PH. Our results demonstrated that QTL x environment interaction is an important property of many QTLs, even for highly heritable traits such as height and maturity. Information about QTL x environment interaction is essential if marker-assisted selection is to be applied to the manipulation of quantitative traits.

14-3-3 protein in the CSF of patients with rapidly progressive dementia

BACKGROUND

The presence of 14-3-3 protein in the CSF has been described to have high sensitivity and specificity for Creutzfeldt-Jakob disease (CJD).

OBJECTIVE

To relate 14-3-3 protein in the CSF with the clinical diagnoses of diseases causing rapidly progressive dementia.

METHODS

The authors studied 46 patients with rapidly progressive dementia that was classified into three diagnostic groups: definitive or probable CJD, possible CJD, and other diagnoses. The definitive or probable CJD group comprised 17 patients (3 definitive sporadic, 1 probable iatrogenic, 3 familial, and 10 probable sporadic CJD cases), the possible CJD group was composed of 7 patients, and the group with other diagnoses had 22 patients. Detection of the 14-3-3 protein was done by the immunoblotting method.

RESULTS

In the definitive or probable CJD group, the test for 14-3-3 protein in CSF was positive in 14 (82%) cases, whereas 3 patients (1 probable sporadic and 2 familial cases) had negative results. CSF was positive for 14-3-3 protein in three of seven cases with possible CJD (42%). In the group with other diagnoses, three individuals had false-positive results (13%). Their diagnoses were definitive Alzheimer's disease, hypercalcemia, and multiple intracerebral hemorrhages.

CONCLUSIONS

The detection of 14-3-3 protein in CSF is a useful in vivo diagnostic test for CJD and, when used in the appropriate clinical context, shows a good correlation to CJD. The presence of the 14-3-3 protein in the CSF reinforces the CJD clinical diagnosis but may not be able to differentiate CJD from other causes of rapidly progressive dementia in everyday clinical practice.

Identification of QTL for growth- and grain yield-related traits in rice across nine locations of Asia

Rice double-haploid (DH) lines of an indica and japonica cross were grown at nine different locations across four countries in Asia. Genotype-by-environment (G x E) interaction analysis for 11 growth- and grain yield-related traits in nine locations was estimated by AMMI analysis. Maximum G x E interaction was exhibited for fertility percentage number of spikelets and grain yield. Plant height was least affected by environment, and the AMMI model explained a total of 76.2% of the interaction effect. Mean environment was computed by averaging the nine environments and subsequently analyzed with other environments to map quantitative trait loci (QTL). QTL controlling the 11 traits were detected by interval analysis using mapmaker/qtl. A threshold LOD of >/=3.20 was used to identify significant QTL. A total of 126 QTL were identified for the 11 traits across nine locations. Thirty-four QTL common in more than one environment were identified on ten chromosomes. A maximum of 44 QTL were detected for panicle length, and the maximum number of common QTL were detected for days to heading detected. A single locus for plant height (RZ730-RG810) had QTL common in all ten environments, confirming AMMI results that QTL for plant height were affected the least by environment, indicating the stability of the trait. Two QTL were detected for grain yield and 19 for thousand-grain weight in all DH lines. The number of QTL per trait per location ranged from zero to four. Clustering of the QTL for different traits at the same marker intervals was observed for plant height, panicle number, panicle length and spikelet number suggesting that pleiotropism and or tight linkage of different traits could be the possible reason for the congruence of several QTL. The many QTL detected by the same marker interval across environments indicate that QTL for most traits are stable and not essentially affected by environmental factors.

Activation of platelets adhered on amorphous hydrogenated carbon (a-C:H) films synthesized by plasma immersion ion implantation-deposition (PIII-D)

Amorphous carbon films have attracted much attention recently due to their good biocompatibility. Diamond-like carbon (DLC), one form of amorphous carbon that is widely used in many kinds of industries, has been proposed for use in blood contacting medical devices. However, the blood coagulation mechanism on DLC in a biological environment is not well understood. Platelet adhesion and activation are crucial events in the interactions between blood and the materials as they influence the subsequent formation of thrombus. In this work, the behavior of platelets adhered onto hydrogenated amorphous carbon films (a-C:H) is investigated. Hydrogenated amorphous carbon films with different hydrogen contents, structures, and chemical bonds were fabricated at room temperature using plasma immersion ion implantation-deposition (PIII-D). The wettability of the films was investigated by contact angle measurements using several common liquids. Platelet adhesion experiments were conducted to examine the interaction of blood with the films in vitro and the activation of adherent platelets. The results show that the behavior of the platelets adhered on the a-C:H films is influenced by their structure and chemical bond, and it appears that protein interaction plays a key role in the activation of the adherent platelets.

Hemocompatibility of titanium oxide films

Hemocompatibility is a key property of biomaterials that come in contact with blood. Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. In this paper, we describe our work of improving hemocompatibility with Ti-O thin films prepared by plasma immersion ion implantation and deposition and by sputtering. The structure and surface chemical and physical properties of the films were characterized by X-ray diffraction, Auger electron spectroscopy, atomic force microscopy (AFM), contact angle measurement, and Hall effect measurement. The behavior of fibrinogen adsorption was investigated by 125I radioactive isotope labeling and AFM. Systematic evaluation of hemocompatibility, including in vitro clotting time, thrombin time, prethrombin time, platelet adhesion, and in vivo implantation into dog's ventral aorta or right auricle from 17 to 90 days, proved that Ti-O films have excellent hemocompatibility. It is suggested that the significantly lower interface tension between Ti-O films and blood and plasma proteins and the semiconducting nature of Ti-O films give them their improved hemocompatibility.

Antithrombogenic investigation of surface energy and optical bandgap and hemocompatibility mechanism of Ti(Ta(+5))O2 thin films

Recent improvements in the antithrombogenic properties of blood contacting biomaterials permit a hybrid design of layers for biomedical applications such as artificial heart valves and stents. Using magnetron sputtering and thermal oxidation, titanium oxide thin films containing tantalum. Ti(Ta(+5))O2, are fabricated to meet the challenge of enhanced hemocompatibility. The blood compatibility is evaluated in vitro by clotting time and platelet adhesion measurement, and in vivo experiments are also conducted. The Ti(Ta(+5))O2 films exhibit attractive blood compatibility exceeding that of low isotropic pyrolytic carbon. Physical properties such as surface energy and semiconductivity are found to play important roles. Our calculated results reveal that the smaller surface force gamma(s) of the film and the smaller blood film interfacial tension gamma(c,blood) are partially responsible for the enhancement of the blood compatibility. Based on the optical bandgap model, the film possesses better hemocompatibility because its optical bandgap of 3.2 eV is wider than that of fibrinogen having a bandgap of 1.8 eV. These factors result in thinner protein layers on the film surface, less protein denaturing, and overall excellent antithrombogenic properties.

Familial Creutzfeldt-Jakob disease associated with a point mutation at codon 210 of the prion protein gene

Creutzfeldt-Jakob disease (CJD), the most known human prion disease, is usually sporadic but approximately 15% of the cases are familial. To date, seven CJD cases with codon 210 mutation (GTT to ATT) have been reported in the literature. We describe a case of a 57 year-old woman who presented gait disturbances and rapidly progressive dementia, leading to death four months after onset. Electroencephalogram revealed periodic activity, diffusion-weighted magnetic resonance imaging showed hypersignal in basal ganglia, and test for 14-3-3 protein was strongly positive in the CSF. The complete prion protein gene coding region was sequenced after PCR amplification, showing a point mutation in codon 210. This is the first case of CJD with codon 210 mutation diagnosed in Brazil. We emphasize the role of genetic search for prion protein gene mutation, even in patients presenting clinical features resembling sporadic CJD.

[Human toll like receptor gene expression in human pulmonary granule epithelial cells and umbilical vein endothelial cells]

OBJECTIVE

To determine whether human Toll like receptors (TLRs) genes are expressed in human lung granule epithelial cells and umbilical vein endothelial cells (UVECs).

METHODS

Specific primers for TLR2 and TLR4 were designed and total RNAs were isolated from human monocyte cell line THP-1, human lung granule epithelial cell line SPC-A-1 and the primary culture of human UVECs. RT-PCR and Northern blotting with digoxin labeling were used for the detection of TLR2 and TLR4 mRNA expression.

RESULTS

TLR4 mRNA expressed in the three types of cells mentioned above. TLR2 mRNA was detected in THP-1 and UVECs, but not in SPC-A-1 cells. By using DNA sequencing, the RT-PCR products were confirmed to be TLR2 and TLR4 cDNAs.

CONCLUSION

This study provided evidence indicating that Toll like receptor genes constitutively express not only in human monocytes but also in human larger vascular endothelial cells and pulmonary granule epithelial cells.

Can we do better with postoperative pain management?

BACKGROUND

In the last decade, there has been heightened awareness that pain management needs to be a priority for all health care settings and clinicians. The article will overview practice guidelines and new technology, and assess their impact on pain relief in inpatient and outpatient surgeries from a patient's perspective.

METHODS

Literature was retrieved by searches from 1996 to 2000 Medline and CINAHL (nursing database), using keywords "postoperative pain," "postsurgical pain," "patient outcomes," "pain outcomes," "survey," "questionnaire," and "practice guidelines."

RESULTS

Overall, current practice standards have had minimal impact on decreasing patients' reports of pain. The incidence of moderate to severe pain with cardiac, abdominal, and orthopedic inpatient procedures has been reported as high as 25% to 50%, and incidence of moderate pain after ambulatory procedures is 25% or higher.

CONCLUSIONS

Despite the advances, the incidence of pain remains high. Yet the future is promising, with new standards from the Joint Commission on Accreditation of Health care Organizations paving the way for reduction of institutional barriers and improved implementation of guidelines.

Are the dominant and recessive plant disease resistance genes similar? A case study of rice R genes and Xanthomonas oryzae pv. oryzae races

The resistance of rice to its bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo) has both qualitative and quantitative components that were investigated using three near-isogenic line sets for four resistance (R) genes (Xa4, xa5, xa13, and Xa21) and 12 Xoo races. Our results indicate that these two resistance components of rice plants were associated with the properties of the R genes. The qualitative component of the R genes was reflected by their large effects against corresponding avirulent Xoo races. The quantitative component of the R genes was their residual effects against corresponding virulent races and their epistatic effects, which together could lead to high-level resistance in a race-specific manner. Our results revealed important differences between the different types of R genes. Two R genes, Xa4 and Xa21, showed complete dominance against the avirulent Xoo races and had large residual effects against virulent ones. They acted independently and cumulatively, suggesting they are involved in different pathways of the rice defensive system. The third R gene, xa5, showed partial dominance or additivity to the avirulent Xoo races and had relatively small but significant residual effects against the virulent races. In contrast, xa13 was completely recessive, had no residual effects against the virulent races, and showed more pronounced race specificity. There was a strong interaction leading to increased resistance between xa13 and xa5 and between either of them and Xa4 or Xa21, suggesting their regulatory roles in the rice defensive pathway(s). Our results indicated that high-level and durable resistance to Xoo should be more efficiently achieved by pyramiding different types of R genes.

Effect of nicotine on vasoconstrictor and vasodilator responses in human skin vasculature

Our objective was to test the hypothesis that acute exposure of human skin vasculature to nicotine may have deleterious effects on endothelial function. Vasoconstriction and vasorelaxation in isolated perfused human skin flaps (approximately 8 x 18 cm) derived from dermolipectomy specimens were assessed by studying changes in skin perfusion pressure measured by a pressure transducer, and skin perfusion was assessed by a dermofluorometry technique (n = 4 or 5). It was observed that nicotine (10(-7) M) amplified (P < 0.05) the norepinephrine (NE)-induced concentration-dependent (10(-7)-10(-5) M) increase in skin vasoconstriction compared with the control. This amplification effect of nicotine in NE-induced skin vasoconstriction was not blocked by the nicotine-receptor antagonist hexamethonium (10(-6) M) or the cyclooxygenase inhibitor indomethacin (10(-5) M). It was also observed that ACh and nitroglycerin (NTG) elicited a concentration-dependent (10(-8)-10(-5) M) vasorelaxation in skin flaps preconstricted with 8 x 10(-7) M of NE. The vasorelaxation induced by ACh was attenuated (P < 0.05) in the presence of nicotine (10(-7) M) compared with the control. However, skin vasorelaxation induced by NTG was not affected by nicotine (10(-7) M). ACh and NTG are known to induce endothelium-dependent and -independent vasorelaxation, respectively. The present findings were interpreted to indicate that acute exposure of human skin vasculature to nicotine was associated with 1) amplification of NE-induced skin vasoconstriction and 2) impairment of endothelium-dependent skin vasorelaxation. Cyclooxygenase products and nicotine receptors blocked by hexamethonium were not involved in the amplification of NE-induced skin vasoconstriction by nicotine. These findings may provide further insight into the pathogenesis of skin vasospasm in skin flap surgery and skin ischemic disease associated with cigarette smoking or use of smokeless tobacco.

Expression of the REB transcriptional activator in rice grains improves the yield of recombinant proteins whose genes are controlled by a Reb-responsive promoter

The gene encoding the rice transcription factor, REB (rice endosperm bZIP) was cloned from a bacterial artificial chromosome library of rice. The cloned 6,227-bp-long Reb gene is composed of six exons and five introns and is flanked by a 1.2-kb 5' promoter and a 1.2-kb 3' terminator region. The function of the Reb gene was explored by a transient assay by using a rice immature endosperm system. The effector constructs containing the native gene or fusion genes linking Reb to the rice actin (Act) or globulin (Glb) gene promoters and the reporter gene construct Glb-beta-glucuronidase (GUS) were used in this study. When these effector constructs were cotransferred with the reporter uidA gene encoding GUS under the control of the Glb promoter into immature rice endosperm cells, the Glb promoter was activated. The transient GUS expression was 2.0 to 2.5-fold higher with the effector construct than without. When the upstream activation sequence containing the GCCACGT(A/C)AG motifs of the Glb promoter was deleted, the activation by REB was abolished. On the other hand, a gain-of-function experiment showed that inserting the upstream activation sequence into the glutelin-1 (Gt1) promoter made it responsive to activation by REB. When cotransformed with Reb gene, mature transgenic rice grains containing the human lysozyme gene driven by the Glb promoter produced 3.7-fold more lysozyme. Accumulation of recombinant lysozyme in mature seed ranged from 30.57 to 279.61 microg.mg(-1) total soluble protein in individual transformants from 30 independent transformation events. Thus, our results show that REB is not only a transcriptional activator, it can also be used to increase the expression of recombinant protein in transgenic rice grains.

[Spectrophotometric determination of trace copper in electroplating wastewater]

In the presence of CPB and OP, the chromogenic reaction of DBH-PF with Cu(II) was studied. The results show that the purple micelle reaction has high sensitivity in the medium of (CH2)6N4-HCl(pH = 5.4) buffered solution, the molar absorptivity is 1.8 x 10(5) L.mol-1.cm-1, and Beer's law is obeyed for Cu(II) in the range of 0.0-9.0 micrograms.25 mL-1 at 540 nm. Combined with solvent extraction separation, the method has been applied to the determination of trace Cu in electroplating wastewater with satisfactory results.

[K. pneumoniea endotoxin induced mice beta-defensin-4 mRNA expression and its signaling transduction]

OBJECTIVE

To investigate the in vivo effects of Klebsiella pneumoniae endotoxin(LPS) on beta-defensin expression and the relevant signaling transduction pathway.

METHODS

A LPS tolerant mouse C3H/HeJ with a point mutation at Toll-like receptor-4 (TLR4) gene and its wild type strain C3H/HeN were used in this study. C3H/HeJ and C3H/HeN were injected with 4 mg/kg of LPS intraperitoneally. The tracheas, lungs and kidneys of the C3H/HeJ and C3H/HeN were collected respectively at different LPS-treated time points, and the total RNA of each sample was extracted. The expression of mice beta-defensin-3 and/or beta-defensin-4 mRNA in these tissues was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). The sequence of cDNA amplified from the lung of C3H/HeN treated by LPS for 24 h was analyzed. By using western blot, p-I kappa B alpha (phosphorylated I kappa B alpha) and I kappa B alpha of in the lungs of C3H/HeJ and C3H/HeN were detected at different time points after treatment with LPS or without LPS.

RESULTS

1. beta-defensin-4 mRNA was detected in the lungs of C3H/HeN after 24 h treatment with LPS. In contrast, no signal was determined in C3H/HeJ mice with LPS treatment and the C3H/HeN mice without LPS treatment. 2. Compared with the control, increas of the p-I kappa B alpha was observed in the lungs of C3H/HeN at 4 h after treatment with LPS, while both the p-I kappa B alpha and I kappa B alpha contents showed a tendency to go down at 8 h after treatment and dramatically decreased at 24 h. But there were no changes in the of p-I kappa B alpha and I kappa B alpha content the lungs of C3H/HeJ under the same conditions.

CONCLUSION

K. pneumoniea endotoxin could induce the expression of beta-defensin-4 mRNA in the lung of C3H/HeN, and TLR4-mediated NF-kappa B activation signaling pathway may be responsible for this event.

[An immunohistochemical study of distribution of insulin in lateral pterygoid muscle after functional mandibular protrusion in rats]

OBJECTIVE

The aim of this study is to investigate the effects of insulin on the lateral pterygoid muscle of growing rats after the functional mandibular protrusion.

METHODS

An immunohistochemical (the ABC method) method was used to detect the location and distribution of insulin in the lateral pterygoid muscle of rats.

RESULTS

1. Insulin located in the cell membrane of the lateral pterygoid muscle. 2. The distribution of insulin in the lateral pterygoid muscle of rats was enhanced after the functional mandibular protrusion.

CONCLUSION

Insulin may play an important role in adaptive remodeling of the lateral pterygoid muscle after the treatment of functional mandibular protrusion.

[Study on the structure-activity relationships of retinoids. II. 3D-QSAR of retinoids and receptor interaction]

Precise prediction of the binding constant of ligand to receptor is an important aspect of structure-based drug design. Almost all methods including de novo design and 3D database search are over concentrated on structure generation rather than quantitative evaluation of the binding properties of the newly produced molecule. Using epididymal retinoic acid binding protein (ERABP) as a model, we simulated the interaction between retinoids and their receptor with DOCK program and obtained an equation for predicting the binding constants. According to the docking conformers of the ligands, CoMFA was also used to deduce a pharmacophoric model of this series of compound.

Amplification effect and mechanism of action of ET-1 in U-46619-induced vasoconstriction in pig skin

The aim of this study was to investigate if a low concentration of endothelin-1 (ET-1; 8 x 10(-10) M) may amplify the skin vasoconstrictor effect of other vasoactive substances in the pathogenesis of skin vasospasm. Pig skin flaps (6 x 16 cm) were perfused with Krebs buffer equilibrated with 95% O(2) and 5% CO(2) at 37 degrees C and pH 7.4. Skin perfusion pressure measured by a pressure transducer and skin perfusion assessed by the dermofluorometry technique were used for assessment of skin vasoconstriction. We observed that ET-1 (8 x 10(-10) M) significantly amplified the concentration-dependent (10(-7)-10(-5) M) skin vasoconstrictor effect of norepinephrine. More importantly, we observed for the first time that this low concentration of ET-1 also amplified the concentration-dependent (10(-8)-10(-6) M) skin vasoconstrictor effect of the thromboxane A(2) mimetic U-46619, and this amplification effect of ET-1 was completely blocked by the protein kinase C (PKC) inhibitor chelerythrine (5 x 10(-6) M). Conversely, the PKC activator phorbol 12,13-dibutyrate (10(-7) M) amplified the vasoconstrictor effect of U-46619. Furthermore, the sensitivity of the skin vasculature to the vasoconstrictor effect of extracellular Ca(2+) in U-46619-induced skin vasoconstriction was significantly enhanced in the presence of 8 x 10(-10) M ET-1. Finally, the cyclooxygenase inhibitor indomethacin (5 x 10(-6) M) did not affect the amplification effect of ET-1 on U-46619-induced skin vasoconstriction. We conclude that a low concentration of ET-1 can amplify the skin vasoconstrictor effect of U-46619 independent of endogenous cyclooxygenase products, and the mechanism may involve activation of PKC and increase in sensitivity of the contractile apparatus to Ca(2+) in smooth muscle cells.