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1.
Int J Antimicrob Agents ; 64(4): 107301, 2024 Aug 14.
Article in English | MEDLINE | ID: mdl-39151647

ABSTRACT

BACKGROUND: Tenofovir-containing antiretroviral therapy regimens may have long-term toxicity-related side effects. This study aimed to compare the virological efficacy of co-formulated darunavir/ritonavir plus lamivudine with darunavir/ritonavir plus tenofovir and emtricitabine or lamivudine. METHODS: The ANDES study was a 48-week, phase 4, randomized, open-label, non-inferiority trial in treatment-naïve adults living with human immunodeficiency virus (HIV). Patients were randomized on a 1:1 basis to receive a daily oral regimen of either dual therapy based on a generic co-formulation of darunavir/ritonavir (800/100 mg) plus a generic lamivudine 300 mg pill, or triple therapy with darunavir/ritonavir plus tenofovir/emtricitabine (300/200 mg) or tenofovir/lamivudine (300/300 mg). The primary endpoint was the proportion of patients with a viral load of <50 copies/mL at week 48 in the intention-to-treat population. The US Food and Drug Administration snapshot algorithm and a non-inferiority margin of -12% were used. The secondary objective was to analyse safety in the per-protocol population. This study has been registered at ClinicalTrials.gov (NCT02770508). RESULTS: Between November 2015 and 31 October 2020, 336 participants were assigned at random to the triple therapy arm (n=165) or the dual therapy arm (n=171). After 48 weeks, 153 patients in the triple therapy group (93%) and 155 patients in the dual therapy group (91%) achieved virological suppression (difference -2.1%, 95% confidence interval -7.0 to 2.9). Drug-related adverse events were more common in the triple therapy group (P=0.04). Two toxicity-related events led to discontinuation in each group. INTERPRETATION: Co-formulated darunavir/ritonavir plus lamivudine showed non-inferiority and a safer toxicity profile compared with the standard-of-care triple therapy regimen including tenofovir in treatment-naïve patients.

2.
Geriatr Nurs ; 53: 270-279, 2023.
Article in English | MEDLINE | ID: mdl-37598431

ABSTRACT

The present pilot study explored the research aim of understanding how independent-living older adults experience social isolation and loneliness and whether virtual tour digital technology can increase social connectedness (N = 10). Through triangulation of interviews, experiences, and feedback, this study contributes to the knowledge base on the well-being of our ageing populations and how digital technologies, specifically virtual tourism, can aid in this process. The key findings reveal that the participants in our study were moderately lonely but were open to embracing more digital technology, sharing how it is instrumental in facilitating social connection and life administration. Participating in virtual tour experiences was well accepted as participants expressed enjoyment, nostalgia, and interest in future use. However, its contribution to increasing social connections needs to be clarified and requires further investigation. Several future research and education directions are provided.


Subject(s)
Loneliness , Social Isolation , Humans , Aged , Pilot Projects , Aging
3.
Article in English | MEDLINE | ID: mdl-37027731

ABSTRACT

In this paper, we explore how virtual replicas can enhance Mixed Reality (MR) remote collaboration with a 3D reconstruction of the task space. People in different locations may need to work together remotely on complicated tasks. For example, a local user could follow a remote expert's instructions to complete a physical task. However, it could be challenging for the local user to fully understand the remote expert's intentions without effective spatial referencing and action demonstration. In this research, we investigate how virtual replicas can work as a spatial communication cue to improve MR remote collaboration. This approach segments the foreground manipulable objects in the local environment and creates corresponding virtual replicas of physical task objects. The remote user can then manipulate these virtual replicas to explain the task and guide their partner. This enables the local user to rapidly and accurately understand the remote expert's intentions and instructions. Our user study with an object assembly task found that using virtual replica manipulation was more efficient than using 3D annotation drawing in an MR remote collaboration scenario. We report and discuss the findings and limitations of our system and study, and present directions for future research.

4.
Eur J Paediatr Dent ; 23(2): 111-115, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35722841

ABSTRACT

AIM: Early extraction of first permanent molars (FPMs) is generally considered successful when the second permanent molar and premolar come into contact, regardless of whether the patient has a healthy occlusion. In this study, we aimed to investigate cases in which early extraction had a successful prognosis. METHODS: Study design: Pre-extraction orthopantomograms of children whose one or more FPMs were extracted were examined retrospectively. Post-extraction parameters such as status of the extraction gap, any other diastema formation, and midline shift were evaluated clinically and radiographically. For the dental age estimations, development levels of the teeth were scored using the Demirjian method and the developmental status of a particular tooth was calculated in years based on tables given by Willems et al. [2001]. The ICON index was used to determine the orthodontic treatment needs of patients. STATISTICS: Descriptive analyses and the Kruskal-Wallis test were used for the statistical analysis of the data. CONCLUSION: Early extraction of FPM should be considered successful when there is no formation of any other diastema in the relevant quadrant, midline shift, or orthodontic treatment needs due to extraction.


Subject(s)
Diastema , Tooth Extraction , Bicuspid/diagnostic imaging , Child , Diastema/etiology , Follow-Up Studies , Humans , Molar/diagnostic imaging , Molar/surgery , Retrospective Studies , Tooth Extraction/methods
5.
HIV Med ; 22(4): 254-261, 2021 04.
Article in English | MEDLINE | ID: mdl-33336523

ABSTRACT

OBJECTIVES: To assess the effect of protease inhibitor (PI)-based dual therapy on CD4/CD8 ratio during the first year of therapy in antiretroviral therapy (ART)-naïve patients using data from randomized controlled clinical trials. METHODS: We pooled data from the GARDEL and ANDES studies, both randomized controlled clinical trials that recruited ART-naïve people living with HIV and randomly assigned them to receive PI-based dual therapy (DT) or triple therapy (TT) aiming to compare viral efficacy. We compared median CD4/CD8 ratios and the proportion of patients with CD4/CD8 ratio > 1 at 48 weeks after ART initiation in both treatment arms using the Mann-Whitney U-test and the χ2 test. We performed subgroup analysis for patients > 50 years old, with baseline CD4 counts ≤ 200 cells/µL, viral load > 100 000 HIV RNA copies/mL, and ritonavir-boosted lopinavir-based therapy. RESULTS: We analysed data from 571 patients: 292 on DT and 279 on TT. No differences were observed in CD4/CD8 ratio (0.632 vs. 0.617, P = 0.729) or in the proportion of patients with CD4/CD8 ratio > 1 (17.9% vs. 19.3%, P = 0.678) 48 weeks after ART initiation. Subgroup analysis showed no further differences. CONCLUSION: The impact of PI-based DT regimens on the CD4/CD8 ratio during the first year of treatment for ART-naïve patients is similar to that of TT.


Subject(s)
Anti-HIV Agents , HIV Infections , HIV Protease Inhibitors , HIV-1 , CD4 Lymphocyte Count , CD8-Positive T-Lymphocytes , HIV Infections/drug therapy , Humans , Lamivudine/therapeutic use , Middle Aged , Reverse Transcriptase Inhibitors , Ritonavir/pharmacology , Ritonavir/therapeutic use , Viral Load
6.
IEEE Trans Vis Comput Graph ; 24(11): 2974-2982, 2018 11.
Article in English | MEDLINE | ID: mdl-30387715

ABSTRACT

The advancements in Mixed Reality (MR), Unmanned Aerial Vehicle, and multi-scale collaborative virtual environments have led to new interface opportunities for remote collaboration. This paper explores a novel concept of flying telepresence for multi-scale mixed reality remote collaboration. This work could enable remote collaboration at a larger scale such as building construction. We conducted a user study with three experiments. The first experiment compared two interfaces, static and dynamic IPD, on simulator sickness and body size perception. The second experiment tested the user perception of a virtual object size under three levels of IPD and movement gain manipulation with a fixed eye height in a virtual environment having reduced or rich visual cues. Our last experiment investigated the participant's body size perception for two levels of manipulation of the IPDs and heights using stereo video footage to simulate a flying telepresence experience. The studies found that manipulating IPDs and eye height influenced the user's size perception. We present our findings and share the recommendations for designing a multi-scale MR flying telepresence interface.


Subject(s)
Computer Graphics , Imaging, Three-Dimensional/methods , Space Perception/physiology , Spatial Navigation/physiology , Virtual Reality , Adult , Algorithms , Female , Humans , Male , User-Computer Interface , Young Adult
7.
IEEE Trans Vis Comput Graph ; 22(11): 2413-22, 2016 11.
Article in English | MEDLINE | ID: mdl-27479970

ABSTRACT

We present results from research exploring the effect of sharing virtual gaze and pointing cues in a wearable interface for remote collaboration. A local worker wears a Head-mounted Camera, Eye-tracking camera and a Head-Mounted Display and shares video and virtual gaze information with a remote helper. The remote helper can provide feedback using a virtual pointer on the live video view. The prototype system was evaluated with a formal user study. Comparing four conditions, (1) NONE (no cue), (2) POINTER, (3) EYE-TRACKER and (4) BOTH (both pointer and eye-tracker cues), we observed that the task completion performance was best in the BOTH condition with a significant difference of POINTER and EYETRACKER individually. The use of eye-tracking and a pointer also significantly improved the co-presence felt between the users. We discuss the implications of this research and the limitations of the developed system that could be improved in further work.

8.
Arch Virol ; 158(9): 1907-15, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23553458

ABSTRACT

Even though new drugs have been approved for treatment of hepatitis C virus (HCV) infection, the risk of drug-drug interactions and concern about overlapping toxicities has hindered the development of studies in HIV/HCV-coinfected individuals. Traditional treatment with pegylated interferon plus ribavirin (peg-IFN + RBV) is very expensive and has a low rate of sustained virological response in coinfected patients, especially if they are infected with HCV genotype 1. Nitazoxanide (NTZ) is a drug that is being evaluated for the treatment of chronic HCV infection, both in HCV-monoinfected and HIV/HCV-coinfected patients. Understanding the NTZ resistance mechanism could allow the development of resistance to be minimized and would expand the treatment options, mainly in special populations such as HIV/HCV-coinfected patients. Similarly to IFN, NTZ increases the activity of the cellular protein kinase activated by double-stranded RNA (PKR), a key kinase in the innate antiviral response. In order to elucidate whether sequence heterogeneity in the PKR-binding domain of HCV NS5A genotype 1 could influence the antiviral activity of either NTZ monotherapy or peg-IFN + RBV, baseline and end-of-therapy plasma samples from two groups of eleven non-responder HIV/HCV-coinfected patients that had received NTZ or peg-IFN + RBV were studied. Most of the HCV NS5A sequences examined at the end of therapy did not change from the baseline, even after 30 days course of antiviral therapy. An extensive comparison of HCV NS5A genotype 1 and 4 sequences from the database with reported IFN therapy outcome was performed in order to infer their phylogenetic relationships. The HCV genotype 1 NS5A nucleotide sequences from therapy-non-responder patients were intermingled amongst those from the database, irrespective of their IFN-therapy outcome. When comparing NS5A-PKRBD amino acid sequences, significant differences were observed in genotype 4, but not in genotype 1 (p < 0.0001 and p > 0.05, respectively). In conclusion, despite IFN and NTZ sharing the protein kinase activated by double-stranded RNA as their cellular target, the HCV genotype 1 strategy to counteract the IFN action mediated by NS5A ISDR/PKRBD does not explain drug resistance in HIV/HCV-coinfected patients. Other viral factors that are possibly involved are discussed as well.


Subject(s)
Antiviral Agents/therapeutic use , HIV Infections/complications , Hepacivirus/drug effects , Hepacivirus/genetics , Sequence Analysis, DNA , Treatment Failure , Viral Nonstructural Proteins/genetics , Amino Acid Sequence , Coinfection/drug therapy , Coinfection/virology , Drug Therapy, Combination , Genotype , HIV Infections/drug therapy , HIV Infections/virology , Hepacivirus/classification , Hepatitis C, Chronic/complications , Hepatitis C, Chronic/drug therapy , Hepatitis C, Chronic/virology , Humans , Interferons/pharmacology , Interferons/therapeutic use , Molecular Sequence Data , Nitro Compounds , Polyethylene Glycols/pharmacology , Polyethylene Glycols/therapeutic use , Ribavirin/pharmacology , Ribavirin/therapeutic use , Sequence Alignment , Thiazoles/pharmacology , Thiazoles/therapeutic use , Viral Nonstructural Proteins/chemistry
9.
MMW Fortschr Med ; 154 Suppl 2: 33-40, 2012 Jun 28.
Article in German | MEDLINE | ID: mdl-23424753

ABSTRACT

BACKGROUND: Persons with migration background exhibit higher smoking rates in comparison to the general population.These smokers often cannot be reached by prevention measures at the family doctor's office. METHODS: In summer 2011 the health campaign "Smoke-free by Ramadan" was launched in 11 German cities. Measures included the training of doctors on smoking cessation methods, general bilingual information flyers, and in some cases lectures on smoking, specifically for imams. A number of local events, especially for individuals with Turkish migration background were initiated. For these health events a specially equipped health bus of the BKK-vor-Ort was used, in which visitors were offered following elements: systematic data collection about age, sex and smoking behavior, a test to determine of the severity of nicotine dependence (Fagerström test, FTNA), as well as spirometric lung function test. Smokers were generally motivated to stop smoking. Data were anonymously collected and analysed in a documentation and communication sheet in Turkish language, and test results were handed over to participants on a printed information sheet. RESULTS: Data of 1012 people collected on 8 health days were analysed (70% men, mean age 46.5 years). The percentage of smokers was 41.5% (men) or 30% (women). Of 294 male smokers, according to FTNA 43.6% had low, 24.8% had moderate, and 31.6% strong nicotine dependence; in the 91 female smokers the corresponding rates were 54.9%, 30.8% and 14.3%. The distribution pattern of the dependency levels was statistically significantly different between genders (p = 0.006). Reduced lung function (FEV, < 80%) occurred in smokers more often than in nonsmokers (30% versus 21%). CONCLUSIONS: These results reinforce the importance of low-threshold prevention measures. By screening, here shown by the example of individuals with Turkish migration background, a significant number of smokers was identified who had in addition to strong nicotine addiction also significantly impaired lung function. As the odds for successful cessation without support are below 5%, evidence-based smoking cessation was advised to all smokers.


Subject(s)
Emigrants and Immigrants , Health Promotion/organization & administration , Holidays , Islam , Smoking Cessation/ethnology , Smoking Prevention , Smoking/ethnology , Tobacco Use Disorder/ethnology , Tobacco Use Disorder/rehabilitation , Adolescent , Adult , Aged , Aged, 80 and over , Cross-Sectional Studies , Emigrants and Immigrants/statistics & numerical data , Female , Germany , Humans , Male , Mass Screening/organization & administration , Middle Aged , Mobile Health Units , Patient Compliance/ethnology , Patient Education as Topic , Smoking/epidemiology , Tobacco Use Disorder/epidemiology , Turkey/ethnology , Young Adult
10.
Antiviral Res ; 92(3): 497-9, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22020160

ABSTRACT

There are two new drugs approved and several in development for treatment of chronic HCV; among them nitazoxanide (NTZ). Twelve HIV/HCV genotype 1 co-infected patients were enrolled prospectively to receive a 30 days course of oral NTZ 500 mg bid. This therapy was well tolerated in this group of HIV patients co-infected with HCV genotype 1. Nevertheless no changes in HCV viral load were observed during treatment in none of the patients evaluated. This data suggests that despite the promising results reported for HCV genotype 4 mono-infected patients, NTZ exhibit poor activity as monotherapy in HIV/HCV co-infected patients with genotype 1.


Subject(s)
Antiviral Agents/therapeutic use , Coinfection/drug therapy , HIV Infections/complications , Hepatitis C, Chronic/drug therapy , Thiazoles/therapeutic use , Viral Load/drug effects , Adult , Antiviral Agents/administration & dosage , Female , Genotype , Hepacivirus/genetics , Hepatitis C, Chronic/complications , Hepatitis C, Chronic/virology , Humans , Male , Middle Aged , Nitro Compounds , Pilot Projects , Thiazoles/administration & dosage , Treatment Failure
11.
Biotechnol Appl Biochem ; 52(Pt 2): 167-75, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18412541

ABSTRACT

The gene encoding Psp HJ147 UDG (Psychrobacter sp. HJ147 uracil-DNA glycosylase) was cloned and sequenced. The gene consists of 735 bp for coding a protein with 244 amino acid residues. The deduced amino acid sequence of Psp HJ147 UDG showed a high similarity to that of Psychrobacter articus, Psychrobacter cryohalolentis K5 and Psychrobacter sp. PRwf-1. The PCR-amplified Psp HJ147 UDG gene was expressed under the control of the T7lac promoter on pTYB1 in Escherichia coli BL21(DE3). The expressed enzyme was purified with IMPACT-CN (intein-mediated purification with an affinity chitin-binding tag) system. The optimum pH and temperature of the purified enzyme were 7.0-7.5 and 20-25 degrees C respectively. The optimum NaCl and KCl concentrations for the activity of the purified enzyme ranged from 50 to75 mM. The half-life of the enzyme at 50 degrees C was approx. 45 s. These heat-labile characteristics enabled Psp HJ147 UDG to control carry-over contamination in direct PCR without loss of the PCR product. Psp HJ147 UDG's contaminant control in both direct PCR and indirect PCR exhibited superiority over the UDG of the marine psychrophilic bacterium strain BMTU 3346 and that of E. coli.


Subject(s)
Hot Temperature , Polymerase Chain Reaction/methods , Psychrobacter/enzymology , Uracil-DNA Glycosidase/genetics , Uracil-DNA Glycosidase/metabolism , Amino Acid Sequence , Biocatalysis , Cloning, Molecular , Enzyme Stability , Gene Expression , Sequence Analysis, DNA , Uracil-DNA Glycosidase/chemistry , Uracil-DNA Glycosidase/isolation & purification
12.
Int J STD AIDS ; 19(12): 866-7, 2008 Dec.
Article in English | MEDLINE | ID: mdl-19050223

ABSTRACT

SUMMARY: A 41-year-old pregnant woman with multiple virological failures started darunavir, enfuvirtide, zidovudine and lamivudine at week 28 of pregnancy. During week 38, the patient had a viral load <400 copies/mL and a CD4 count of 180 cells/mm(3) (13%). The child was found to be in good health, with negative HIV-polymerase chain reactions at birth, at two and at six months.


Subject(s)
Antiretroviral Therapy, Highly Active , HIV Envelope Protein gp41/therapeutic use , HIV Fusion Inhibitors/therapeutic use , HIV Infections/drug therapy , HIV Protease Inhibitors/therapeutic use , Peptide Fragments/therapeutic use , Sulfonamides/therapeutic use , Adult , CD4 Lymphocyte Count , Darunavir , Drug Resistance, Multiple, Viral , Drug Therapy, Combination , Enfuvirtide , Female , HIV Envelope Protein gp41/administration & dosage , HIV Fusion Inhibitors/administration & dosage , HIV Infections/virology , HIV Protease Inhibitors/administration & dosage , HIV-1/drug effects , Humans , Infant, Newborn , Peptide Fragments/administration & dosage , Pregnancy , Pregnancy Outcome , Sulfonamides/administration & dosage , Treatment Outcome , Viral Load
13.
Appl Environ Microbiol ; 74(21): 6563-9, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18791030

ABSTRACT

The known archaeal family B DNA polymerases are unable to participate in the PCR in the presence of uracil. Here, we report on a novel archaeal family B DNA polymerase from Nanoarchaeum equitans that can successfully utilize deaminated bases such as uracil and hypoxanthine and on its application to PCR. N. equitans family B DNA polymerase (Neq DNA polymerase) produced lambda DNA fragments up to 10 kb with an approximately 2.2-fold-lower error rate (5.53 x 10(-6)) than Taq DNA polymerase (11.98 x 10(-6)). Uniquely, Neq DNA polymerase also amplified lambda DNA fragments using dUTP (in place of dTTP) or dITP (partially replaced with dGTP). To increase PCR efficiency, Taq and Neq DNA polymerases were mixed in different ratios; a ratio of 10:1 efficiently facilitated long PCR (20 kb). In the presence of dUTP, the PCR efficiency of the enzyme mixture was two- to threefold higher than that of either Taq and Neq DNA polymerase alone. These results suggest that Neq DNA polymerase and Neq plus DNA polymerase (a mixture of Taq and Neq DNA polymerases) are useful in DNA amplification and PCR-based applications, particularly in clinical diagnoses using uracil-DNA glycosylase.


Subject(s)
DNA-Directed DNA Polymerase/metabolism , Nanoarchaeota/enzymology , Polymerase Chain Reaction/methods , Bacteriophage lambda/genetics , DNA, Viral/genetics , DNA-Directed DNA Polymerase/isolation & purification , Hypoxanthine/metabolism , Molecular Weight , Substrate Specificity , Uracil/metabolism
14.
Environ Microbiol ; 10(12): 3212-24, 2008 Dec.
Article in English | MEDLINE | ID: mdl-18647334

ABSTRACT

DNA ligases are divided into two groups according to their cofactor requirement to form ligase-adenylate, ATP-dependent DNA ligases and NAD(+)-dependent DNA ligases. The conventional view that archaeal DNA ligases only utilize ATP has recently been disputed with discoveries of dual-specificity DNA ligases (ATP/ADP or ATP/NAD(+)) from the orders Desulfurococcales and Thermococcales. Here, we studied DNA ligase encoded by the hyperthermophilic crenarchaeon Sulfophobococcus zilligii. The ligase exhibited multiple cofactor specificity utilizing ADP and GTP in addition to ATP. The unusual cofactor specificity was confirmed via a DNA ligase nick-closing activity assay using a fluorescein/biotin-labelled oligonucleotide and a radiolabelled oligonucleotide. The exploitation of GTP as a catalytic energy source has not to date been reported in any known DNA ligase. This phenomenon may provide evolutionary evidence of the nucleotide cofactor utilization by DNA ligases. To bolster this hypothesis, we summarize and evaluate previous assertions. We contend that DNA ligase evolution likely started from crenarchaeotal DNA ligases and diverged to eukaryal DNA ligases and euryarchaeotal DNA ligases. Subsequently, the NAD(+)-utilizing property of some euryarchaeotal DNA ligases may have successfully differentiated to bacterial NAD(+)-dependent DNA ligases.


Subject(s)
Coenzymes/pharmacology , DNA Ligases/genetics , DNA Ligases/metabolism , Desulfurococcaceae/enzymology , Nucleotides/pharmacology , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Amino Acid Sequence , DNA/metabolism , DNA Breaks, Single-Stranded , DNA, Archaeal/chemistry , DNA, Archaeal/genetics , Desulfurococcaceae/genetics , Desulfurococcaceae/metabolism , Evolution, Molecular , Guanosine Triphosphate/metabolism , Molecular Sequence Data , Sequence Alignment , Sequence Analysis, DNA
15.
Appl Microbiol Biotechnol ; 80(5): 785-94, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18626641

ABSTRACT

In this study, the gene encoding Bacillus sp. HJ171 uracil-DNA glycosylase (Bsp HJ171 UDG) was cloned and sequenced. The Bsp HJ171 UDG gene consists of a 738-bp DNA sequence, which encodes for a protein that is 245-amino-acid residues in length. The deduced amino acid sequence of the Bsp HJ171 UDG had a high sequence similarity with other bacterial UDGs. The molecular mass of the protein derived from this amino acid sequence was 27.218 kDa. The Bsp HJ171 UDG gene was expressed under the control of a T7lac promoter in the pTYB1 plasmid in Escherichia coli BL21 (DE3). The expressed enzyme was purified in one step using the Intein Mediated Purification with an Affinity Chitin-binding Tag purification system. The optimal temperature range, pH, NaCl concentration, and KCl concentration of the purified enzyme was 20-25 degrees C, 8.0, 25 and 25 mM, respectively. The half-life of the enzyme at 40 degrees C and 50 degrees C were approximately 131 and 45 s, respectively. These heat-labile characteristics enabled Bsp HJ171 UDG to control carry-over contamination in the polymerase chain reaction product (PCR) without losing the PCR product.


Subject(s)
Bacillus/enzymology , Bacterial Proteins/chemistry , Polymerase Chain Reaction/standards , Uracil-DNA Glycosidase/chemistry , Amino Acid Sequence , Bacillus/classification , Bacillus/genetics , Bacterial Proteins/genetics , Bacterial Proteins/isolation & purification , Bacterial Proteins/metabolism , Cloning, Molecular , Enzyme Stability , Escherichia coli/genetics , Escherichia coli/metabolism , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction/methods , Sequence Alignment , Uracil-DNA Glycosidase/genetics , Uracil-DNA Glycosidase/isolation & purification , Uracil-DNA Glycosidase/metabolism
16.
J Microbiol Biotechnol ; 18(2): 287-94, 2008 Feb.
Article in English | MEDLINE | ID: mdl-18309273

ABSTRACT

Three amino acid residues (His119, Glu164, and Glu338) in the active site of Thermus caldophilus GK24 beta- glycosidase (Tca beta-glycosidase), a family 1 glycosyl hydrolase, were mutated by site-directed mutagenesis. To verify the key catalytic residues, Glu164 and Glu338 were changed to Gly and Gln, respectively. The E164G mutation resulted in drastic reductions of both beta-galactosidase and beta-glucosidase activities, and the E338Q mutation caused complete loss of activity, confirming that the two residues are essential for the reaction process of glycosidic linkage hydrolysis. To investigate the role of His119 in substrate binding and enzyme activity, the residue was substituted with Gly. The H119G mutant showed 53-fold reduced activity on 5 mM p-nitrophenyl beta-Dgalactopyranoside, when compared with the wild type; however, both the wild-type and mutant enzymes showed similar activity on 5 mM p-nitrophenyl beta-D-glucopyranoside at 75degreeC. Kinetic analysis with p-nitrophenyl beta-D-galactopyranoside revealed that the kcat value of the H119G mutant was 76.3-fold lower than that of the wild type, but the Km of the mutant was 15.3-fold higher than that of the wild type owing to the much lower affinity of the mutant. Thus, the catalytic efficiency (kcat/Km) of the mutant decreased to 0.08% to that of the wild type. The kcat value of the H119G mutant for p-nitrophenyl beta- D-glucopyranoside was 5.1-fold higher than that of the wild type, but the catalytic efficiency of the mutant was 2.5% of that of the wild type. The H119G mutation gave rise to changes in optima pH (from 5.5-6.5 to 5.5) and temperature (from 90 degrees C to 80-85 degrees C). This difference of temperature optima originated in the decrease of H119G's thermostability. These results indicate that His119 is a crucial residue in beta- galactosidase and beta-glucosidase activities and also influences the enzyme's substrate binding affinity and thermostability.


Subject(s)
Mutation, Missense , Thermus/enzymology , beta-Galactosidase/genetics , beta-Galactosidase/metabolism , Amino Acid Sequence , Amino Acid Substitution , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Binding Sites , Enzyme Stability , Hydrogen-Ion Concentration , Kinetics , Molecular Sequence Data , Mutagenesis, Site-Directed , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Alignment , Substrate Specificity , Thermus/chemistry , Thermus/genetics , beta-Galactosidase/chemistry
18.
Article in Russian | MEDLINE | ID: mdl-695940

ABSTRACT

In experiments on cats it was shown that the creation of generator of pathologically intensified excitation (GPiE) in the orbital cortex resulted in certain pathological changes of sleep. These changes were expressed in a shortening of the wakefulness period and prolongation of the sleep state, the relationship between slow-wave and paradoxical sleep phases remaining unchanged. The results of the investigations confirm the suggestion concerning the participation of the orbito-frontal cortex in sleep induction. The obtained data are analyzed with respect to the general concept about the role of determinant structures in the nervous system activity and the theory of generator mechanisms of neuropathological syndromes characterized by hyperactivity of the systems.


Subject(s)
Frontal Lobe/physiology , Sleep/physiology , Animals , Cats , Electroencephalography , Periodicity , Sleep Stages/physiology , Tetanus Toxin
19.
Biull Eksp Biol Med ; 84(11): 531-4, 1977 Nov.
Article in Russian | MEDLINE | ID: mdl-563254

ABSTRACT

Acute experiments on cats showed that injection of tetanus toxin into the orbital cortex (which destroys various types of inhibition) resulted in the formation of a local generator of pathologically enhanced excitation in this cortex area. Chronic experiments showed that cats with such a generator in the orbital cortex developed pathological changes of sleep, expressed in reduction of the duration of wakefulness and development of the slow-wave and paradoxical sleep phases being, retained. The results of this investigation confirm the view on the participation of the orbitofrontal cortex in sleep induction. They are in favour of the general conception on the role of the determinant structure in the nervous system activity and the theory of the generator mechanisms of the neuropathological syndromes characterized by the hyperactivity of the system.


Subject(s)
Frontal Lobe/physiopathology , Sleep Wake Disorders/physiopathology , Tetanus Toxin/poisoning , Animals , Cats , Electroencephalography , Humans , Sleep Wake Disorders/etiology , Time Factors , Visual Cortex/physiopathology
20.
Fiziol Zh SSSR Im I M Sechenova ; 62(12): 1760-6, 1976 Dec.
Article in Russian | MEDLINE | ID: mdl-1010060

ABSTRACT

In adult cats, it was shown that the orbital cortex had direct contra - and ipsilateral projections to oral and caudal reticular nuclei of the pons, to caudal part of the Guden neuclei, to pons covering nucleus, to sulure nucleus, to trigeminal nuclei, and to such conducting formations, as the trapezoid body and pyramidal tract. The orbital gyri connections were mostly ipsilateral and to the caudal part of caudal reticular nucleus of the pons, to oral part of the reticular giganto-cellular nucleus, and to the own pons nuclei. The highest firing rate and amplitude were recorded in the inhibition zone of the reticular formation (the site of overlapping of the oral and caudal reticular nuclei of the pons).


Subject(s)
Cerebral Cortex/physiology , Pons/physiology , Reticular Formation/physiology , Animals , Brain Mapping , Cats , Cerebral Cortex/drug effects , Electrophysiology , Neural Pathways , Strychnine/pharmacology
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