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Biomedical subjects

E Muller

Publications and source records attributed to E Muller.

At least 19 recordsLinked to original sources
PubMed2007

Molecular analysis of a full-length sequence of a new yam badnavirus from Dioscorea sansibarensis.

Badnavirus-like particles were observed by ISEM in viral preparations from yam (Dioscorea sansibarensis) leaves from Benin. Use of the viral preparation as template for PCR amplification with badnavirus-specific primers gave rise to a 579-bp product with most nucleotide identity (70.8%) to Dioscorea alata bacilliform virus (DaBV, Accession numbers X94575-X94582), the only other yam badnavirus sequenced to date. A full-length badnavirus sequence was generated, which consisted of 7261 nucleotides with a typical Badnavirus genome organisation. The full-length sequence shared most identity (61.9%) to DaBV (Accession numbers X94575-X94582) and hence represents a member of a new badnavirus species termed Dioscorea sansibarensis bacilliform virus (DsBV).

Badnavirus↗
PubMed2006

Molecular ecology and emergence of tropical plant viruses.

An appreciation of the risks caused by emergent plant viruses is critical in tropical areas that rely heavily on agriculture for subsistence and rural livelihood. Molecular ecology, within 10 years, has unraveled the factors responsible for the emergence of several of the economically most important tropical plant viruses: Rice yellow mottle virus (RYMV), Cassava mosaic geminiviruses (CMGs), Maize streak virus (MSV), and Banana streak virus (BSV). A large range of mechanisms--most unsuspected until recently--were involved: recombination and synergism between virus species, new vector biotypes, genome integration of the virus, host adaptation, and long-distance dispersal. A complex chain of molecular and ecological events resulted in novel virus-vector-plant-environment interactions that led to virus emergence. It invariably involved a major agricultural change: crop introduction, cultural intensification, germplasm movement, and new genotypes. A current challenge is now to complement the analysis of the causes by an assessment of the risks of emergence. Recent attempts to assess the risks of emergence of virulent virus strains are described.

Ecosystem↗
PubMed2006

Overview of a paediatric renal transplant programme.

INTRODUCTION: Renal transplantation is the therapy of choice for children with end-stage renal failure. There are many challenges associated with a paediatric programme in a developing country where organs are limited. METHODS: A retrospective review was undertaken of 149 paediatric renal transplants performed between 1968 and 2006 with specific emphasis on transplants performed in the last 10 years. Survival of patients and grafts was analysed and specific problems related to drugs and infections were reviewed. RESULTS: On review of the total programme, 60% of the transplants have been performed in the last 10 years, with satisfactory overall patient and graft survival for the first 8 years post transplant. At this point, transfer to adult units with non-compliance becomes a significant problem. Rejection is less of a problem than previously but infection is now a bigger issue--specifically tuberculosis (TB), cytomegalovirus (CMV) and Epstein-Barr virus (EBV) infections with related complications. A wide variety of drugs are available for tailoring immunosuppression to minimise side-effects. CONCLUSION: It is possible to have a successful paediatric transplant programme in a developing country. However, to improve long-term outcomes certain issues need to be addressed, including reduction of nephrotoxic drugs and cardiovascular risk factors and providing successful adolescent to adult unit transition.

Adolescent↗
PubMed2006

Liver transplantation at Red Cross War Memorial Children's Hospital.

UNLABELLED: The liver transplant programme for infants and children at Red Cross War Memorial Children's Hospital is the only established paediatric service in sub-Saharan Africa. Referrals for liver transplant assessment come from most provinces within South Africa as well as neighbouring countries. PATIENTS AND METHODS: Since 1987, 81 children (range 6 months-14 years) have had 84 liver transplants with biliary atresia being the most frequent diagnosis. The indications for transplantation include biliary atresia (48), metabolic (7), fulminant hepatic failure (10), redo transplants (3) and other (16). Four combined liver/kidney transplants have been performed. Fifty-three were reduced-size transplants with donor/recipient weight ratios ranging from 2:1 to 11:1 and 32 children weighed less than 10 kg. RESULTS: Sixty patients (74%) survived 3 months-14 years post-transplant. Overall cumulative 1- and 5-year patient survival figures are 79% and 70% respectively. However, with the introduction of prophylactic intravenous ganciclovir and the exclusion of hepatitis B virus (HBV) IgG core Ab-positive donors, the 1-year patient survival is 90% and the projected 5-year paediatric survival is > 80%. Early (< 1 month) post-liver-transplant mortality was low. Causes include primary malfunction (1), inferior vena cava thrombosis (1), bleeding oesophageal ulcer (1), sepsis (1) and cerebral oedema (1). Late morbidity and mortality was mainly due to infections: de novo hepatitis B (5 patients, 2 deaths), Epstein-Barr virus (EBV)- related post-transplantation lymphoproliferative disease (12 patients, 7 deaths) and cytomegalovirus (CMV) disease (10 patients, 5 deaths). Tuberculosis (TB) treatment in 3 patients was complicated by chronic rejection (1) and TB-drug-induced subfulminant liver failure (1). CONCLUSION: Despite limited resources, a successful paediatric programme has been established with good patient and graft survival figures and excellent quality of life. Shortage of donors because of infection with HBV and human immunodeficiency virus (HIV) leads to significant waiting-list mortality and infrequent transplantation.

Adolescent↗
PubMed2004

Molecular variability analysis of five new complete cacao swollen shoot virus genomic sequences.

Cacao swollen shoot virus (CSSV), a member of the family Caulimovi-ridae, genus Badnavirus occurs in all the main cacao-growing areas of West Africa. We amplified, cloned and sequenced complete genomes of five new isolates, two originating from Togo and three originating from Ghana. The genome of these five newly sequenced isolates all contain the five putative open reading frames I, II, III, X and Y described for the first sequenced CSSV isolate, Agou1 originating from Togo. Their genomes have been aligned with the genome of Agou1. The nucleotide and amino acid sequence identities between isolates have been calculated and a phylogenetic analysis has been made including other pararetroviruses. Maximum nucleotide sequence variability between complete genomes of CSSV isolates was 29.4%. Geographical differentiation between isolates appears more important than differentiation between mild and severe isolates. ORF X differs greatly in size and sequence between the Togolese isolates Nyongbo2 and Agou1, and the four other isolates, its functional role is therefore clearly questionable.

Badnavirus↗
PubMed2001

Effectiveness of propranolol for cocaine dependence treatment may depend on cocaine withdrawal symptom severity.

Propranolol may reduce symptoms of autonomic arousal associated with early cocaine abstinence and improve treatment outcome. This trial was an 8-week, double-blind, placebo-controlled trial of propranolol in 108 cocaine dependent subjects. The primary outcome measure was quantitative urinary benzoylecgonine levels. Secondary outcome measures included treatment retention, addiction severity index results, cocaine craving, mood and anxiety symptoms, cocaine withdrawal symptoms, and adverse events. Propranolol treated subjects had lower cocaine withdrawal symptom severity but otherwise did not differ from placebo treated subjects in any outcome measure. However, in a secondary, exploratory analysis, subjects with more severe cocaine withdrawal symptoms responded better to propranolol in comparison to placebo. In these subjects, propranolol treatment was associated with better treatment retention and lower urinary benzoylecgonine levels as compared with the placebo treatment. Propranolol may be useful only for the treatment of cocaine dependent patients with severe cocaine withdrawal symptoms.

Adolescent↗
PubMed2001

Convergent synthesis of potent peptide inhibitors of the Grb2-SH2 domain by palladium catalyzed coupling of a terminal alkyne.

A new strategy was developed to prepare in a very efficient and convergent manner C-terminal modified tripeptides with high affinities for the Grb2-SH2 domain. Using Pd(PPh3)2Cl2 as catalyst, selected naphthyl iodides and triflates were coupled to Ac-Pmp(t-Bu)2-Ac6c-Asn-NH(prop-2-ynyl). The resulting alkyne derivatives were hydrogenated and deprotected to afford potent Grb2-SH2 inhibitors.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Effects on the neutral lipid contents of the liver, ileum and serum during experimental schistosomiasis.

During infection of vertebrate hosts with Schistosoma mansoni,worm eggs trapped in host tissues induce granulomatous lesions that interfere with normal organ functions. Even though both the liver and the intestine are particularly susceptible to egg-induced tissue damage, little information is available on the pathobiochemical changes induced in these organs during infection. Using a mouse model, we investigated whether the lipid profiles of the liver and ileum were altered significantly as a result of infection. We found that triacylglycerol and cholesteryl ester levels decreased significantly as infection progressed.

Animals↗
PubMed2001

Early detection of cacao swollen shoot virus using the polymerase chain reaction.

A polymerase chain reaction assay was developed which allows early detection of cacao swollen shoot virus (CSSV) in DNA extracts from cacao plantlets agroinoculated with the Togolese isolate Agou 1. The primers used were derived from badnavirus conserved sequences and nucleic acid was extracted with the Plant DNeasy extraction kit (Qiagen). CSSV genome was detectable between 6 and 20 days after inoculation. The first leaf symptoms appeared after 4 weeks and the first shoot swelling symptoms after 8 weeks.

Badnavirus↗
PubMed2001

GABA(A) receptor cell surface number and subunit stability are regulated by the ubiquitin-like protein Plic-1.

Controlling the number of functional gamma-aminobutyric acid A (GABA(A)) receptors in neuronal membranes is a crucial factor for the efficacy of inhibitory neurotransmission. Here we describe the direct interaction of GABA(A) receptors with the ubiquitin-like protein Plic-1. Furthermore, Plic-1 is enriched at inhibitory synapses and is associated with subsynaptic membranes. Functionally, Plic-1 facilitates GABA(A) receptor cell surface expression without affecting the rate of receptor internalization. Plic-1 also enhances the stability of intracellular GABA(A) receptor subunits, increasing the number of receptors available for insertion into the plasma membrane. Our study identifies a previously unknown role for Plic-1, a modulation of GABA(A) receptor cell surface number, which suggests that Plic-1 facilitates accumulation of these receptors in dendritic membranes.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Pain and dental implantology: sensory quantification and affective aspects. Part I: At the private dental office.

After an extensive review of the dental literature, few articles were found related to pain and implantology. Management of orofacial pain has traditionally been a difficult challenge for the dental-medical profession. Patients may be afraid of dental pain, particularly in cases of dental implantology. Therefore, a study to obtain more conclusive data was developed. Taking into account that the perception of pain and the threshold of pain vary among individuals, a 2-year clinical study was established in private practice utilizing a verbal method (double-blind). The study was used to quantify sensory and affective aspects of pain associated with dental implantology on 75 patients in a private dental office. All of the implants were placed by the same clinician. Data were recorded following a Pain Data Sheet designed for this particular study. The aim of this study was to obtain different aspects of data as follows: 1) Fear of the dentist and fear of dental implant procedures utilizing a descriptive scale of 1 to 10, with 1 indicative of no fear. 2) Dental areas and ridges: Dental pain, pain in edentulous areas, and pain in the implanted area utilizing a scale of 0 to 8, with 0 indicative of no pain. 3) Function and pain: during mastication, swallowing, speech, yawning, opening, closing, and lateral excursions and indication of cervical pain or back pain, each calibrated by the presence or absence of pain. 4) Palpation and pain of the temporomandibular joint, the temporal muscle, the area of the pterygoid muscles, masseter muscle, and sternocleidomastoid muscle, all calibrated on the indication of presence or absence of pain. 5) Others: ear pain, neuralgia, headaches, edema, and hematoma, calibrated on the basis of presence or absence. The aforementioned factors were evaluated immediately before surgery and after surgery, at 24 hours, and during a follow up for a period of 2 years at intervals of 1 week; 1, 2, 3, 4, and 6 months; and 1 and 2 years after surgery. Also recorded were the uses of presurgical and postsurgical medication at the first and second surgical phases, age, sex, buccal opening, number and position of implants, previous dental experiences, and the psychological preparation for dental implant treatment. The results of the statistical analysis indicate no correlation between pain and dental implantology procedures, in a private dental practice, at the level of significance of P > .001.

Adolescent↗
PubMed2000

Intersubband electroluminescence from silicon-based quantum cascade structures.

The quantum cascade laser, which uses electronic transitions within a single band of a semiconductor, constitutes a possible way to integrate active optical components into silicon-based technology. This concept necessitates a transition with a narrow linewidth and an upper state with a sufficiently long lifetime. We report the observation of intersubband electroluminescence from a p-type silicon/silicon-germanium quantum cascade structure, centered at 130 millielectron volts with a width of 22 millielectron volts, with the expected polarization, and discernible up to 180 kelvin. The nonradiative lifetime is found to depend strongly on the design of the quantum well structure, and is shown to reach values comparable to that of an equivalent GaInAs/AlInAs laser structure.

Journal Article↗
PubMed2000

Cooperativity of Staphylococcal aureus enterotoxin B superantigen, major histocompatibility complex class II, and CD80 for immunotherapy of advanced spontaneous metastases in a clinically relevant postoperative mouse breast cancer model.

One of the leading causes of death for women is metastatic breast cancer. Because most animal tumors do not accurately model clinical metastatic disease, the development of effective therapies has progressed slowly. In this study, we establish the poorly immunogenic mouse 4T1 mammary carcinoma as a postsurgical animal model. 4T1 growth characteristics parallel highly invasive human metastatic mammary carcinoma and, at the time of surgery, the extent of disease is comparable with human stage IV breast cancer. Progress in understanding the immune response has led to innovative immune-based anticancer therapies. Here, we test in this postsurgical model, a novel cell-based vaccine, combining MHC class II, CD80(B7.1), and SEB superantigen. Effective treatment of tumor-bearing mice with this immunotherapy requires expression of all three molecules. Mean survival time is extended from 5-7.5 weeks for control-treated mice to 6-10.5 weeks for therapy-treated mice. Increased survival is accompanied by a maximum of 100-fold decrease in clonogenic lung metastases. These therapeutic effects are particularly noteworthy because: (a) the postoperative model demonstrates that early metastases responsible for morbidity are established by 2 weeks after tumor inoculation with 7 x 10(3) parental 4T1 cells into the mammary gland; (b) the immunotherapy is started 4 weeks after tumor inoculation when the mice contain extensive, pre-established, disseminated metastases; and (c) CD4+ and CD8+ T cells are required for the effect.

Animals↗
PubMed2000

Effect of hypothermia on the volume of rat glial cells.

1. The cell volume of suspended C6 glioma cells and primary cultured rat astrocytes was measured at normothermia (37 degrees C), and at mild (32 degrees C) and moderate (27 degrees C) hypothermia by flow cytometry with electrical cell sizing. 2. Under control conditions (37 degrees C), C6 glioma cells had a volume of 809 +/- 29 microm3. Moderate hypothermia (27 degrees C) led to rapid cell swelling, with a maximum volume of 113.1 +/- 1.3 % of control being achieved after 50 min. After rewarming to 37 degrees C, cell volume recovered very slowly and incompletely (to 107.2 +/- 0.4 % of control). Less severe hypothermia (32 degrees C) led to a smaller increase in cell volume (108.7 +/- 0.5 % of control). 3. The maximal cell swelling response and the kinetics of swelling were similar in C6 glioma cells and primary cultured astrocytes. 4. Hypothermia-induced cell swelling was dependent on the presence of extracellular Na+ and was reduced by the Na+-H+ antiporter inhibitor EIPA. 5. The underlying mechanisms of hypothermia-induced cell swelling are an intracellular accumulation of Na+ by (1) differential effects of hypothermia on the membrane permeabilities of Na+ and K+ and (2) activation of the Na+-H+ antiporter by a shift of its activation curve to a more alkaline value.

Animals↗
PubMed2000

Electrospray and chemical ionization mass spectrometry of di-n-butyl sulfate. Unimolecular chemistry of its protonated form and quantification method by liquid chromatography/electrospray ionization tandem mass spectrometry

Di-n-butyl sulfate (DNBS) has been studied by electrospray (ESI) and chemical (CI) ionization mass spectrometry. The use of methanol as solvent in electrospray ionization allows observation of relatively abundant [DNBS + CH(3)OH + H](+) ions (m/z 243) which upon collision dissociate to [DNBS + H](+) ions (m/z 211). In both ESI and CI experiments, it is found that [DNBS + H](+) ions lead to m/z 113 daughter ions. The composition of this m/z 113 fragment ion and its mechanism of formation have been established by high resolution measurements and CID-MIKE experiments. An 'internal substitution' reaction involving an ion-neutral intermediate is proposed to explain the formation of a [C(8)H(17)](+) ion (m/z 113) by loss of a H(2)SO(4) molecule. Finally, a LC/ESI-MS/MS quantification method is proposed in which a detection limit of di-n-butyl sulfate in the ppm range is obtained. It is suggested that the quantification method might be extended to higher dialkyl sulfates. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2000

Surface and friction characterization by thermoelectric measurements during ultrasonic friction processes

Even though friction is one of the oldest problems in physics many aspects of friction processes are not clear today. We present an experimental setup, which permits the study of tribological systems by measuring the dissipated heat at the interface of two surfaces during a friction process with a time resolution of 1 ms. The apparatus is based on a standard ultrasonic wire-bond machine used in semiconductor industries to connect the internal semiconductor die to the external leads, but the standard bond wire is replaced by a thermocouple. To demonstrate the ability of the apparatus it will be shown that bond substrates used in semiconductor industries can be unequivocally characterized.

Journal Article↗