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At least 1,405 records · Page 78Linked to original sources
PubMed2000

The study of locomotor pointing in virtual reality: the validation of a test set-up.

The goal of this experiment was to validate an experimental set-up for studying locomotor pointing. The specific and also original element of this set-up was the interactive nature of virtual reality and movement production. This interaction was achieved through the coupling of a treadmill and a Silicon Graphics system. This latter system generated on a screen (3 x 2.3 m) an environmental array that moved according to the action produced by subjects on a treadmill. The task was to place either foot on a spatial target that appeared on the floor in front of the subject's displacement trajectory. We analyzed the step length patterns of subjects approaching these targets, along with the current target-subject relationship. The results are in agreement with a perception-action coupling type of control mechanism that operates continuously as the subject approaches the desired target. Apparently, these findings mirror observations of real-life locomotion, indicating that the present set-up provides a valid and useful tool for examining human locomotion.

Adult↗
PubMed2001

[Gastrointestinal endoscopy--review and perspectives].

Gastrointestinal endoscopy comprises gastroscopy, colonoscopy, and endoscopic retrograde cholangiopancreatography (ERCP). Endoscopic ultrasonography and small bowel enteroscopy are also available, although not in all endoscopy units. The diagnostic accuracy of gastrointestinal endoscopy is very high. Scientific activities include evaluation of methods/regimens where diagnostic gastroscopy can be replaced by non-invasive Helicobacter screening for certain patients, the use of non-invasive alternatives to ERCP (e.g. magnetic resonance), small bowel enteroscopy without the use of an endoscope, and virtual colonoscopy with computer tomography or magnetic resonance techniques. The move away from traditional endoscopic procedures towards more non-invasive techniques is taking place along with the development of new endoscopic procedures to replace traditional surgical techniques, e.g. endoscopic placement of colonic metal stents in acute colonic obstruction.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1988

Controversies about guidelines to prevent the transmission of human immunodeficiency virus in hospitals in Britain.

The widespread screening of donors of blood, organs and semen for HIV antibody has contributed greatly to the prevention of spread of HIV to patients in British hospitals. The chances of patients acquiring HIV from a contaminated blood transfusion are now estimated at less than 1 in 1 million and factor VIII for haemophiliacs, which is also heat treated, is now virtually always free of HIV contamination. However, the wider use of HIV antibody tests to identify infected patients and rationalize the application of additional 'inoculation risk' precautions, so as to protect staff, is controversial. The risks of hospital staff acquiring HIV following occupational exposure, without such a screening-programme, are extremely low provided a high standard of hygiene is maintained and inoculation injuries are avoided. When needlestick injuries occur, involving HIV infected patients, the chances of transmission of HIV to hospital staff are less than 1 in 100. Current guidelines in Britain depend on use of additional inoculation precautions for patients belonging to HIV risk groups but in practice most of these 'risk patients' are not infected with HIV. Screening HIV antibody tests, preferably with consent, can help the smooth running of operating theatres in areas where many 'risk patients' require surgery, as extra precautions are not necessary for most of these patients who are HIV negative. All antenatal patients should be screened especially in areas of high prevalence of HIV, as this helps to prevent vertical transmission as well as facilitating the rational use of extra precautions to protect health care workers.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Fluorescence in situ hybridization of 16S rRNA gene clones (Clone-FISH) for probe validation and screening of clone libraries.

A method is presented for fluorescence in situ hybridization (FISH) of 16S rRNA gene clones targeting in vivo transcribed plasmid inserts (Clone-FISH). Several different cloning approaches and treatments to generate target-rRNA in the clones were compared. Highest signal intensities of Clone-FISH were obtained using plasmids with a T7 RNA polymerase promoter and host cells with an IPTG-inducible T7 RNA polymerase. Combined IPTG-induction and chloramphenicol treatment of those clones resulted in FISH signals up to 2.8-fold higher than signals of FISH with probe EUB338 to cells of Escherichia coli. Probe dissociation curves for three oligonucleotide probes were compared for reference cells containing native (FISH) or cloned (Clone-FISH) target sequences. Melting behaviour and calculated T(d) values were virtually identical for clones and cells, providing a format to use 16S rRNA gene clones instead of pure cultures for probe validation and optimization of hybridization conditions. The optimized Clone-FISH protocol was also used to screen an environmental clone library for insert sequences of interest. In this application format, 13 out of 82 clones examined were identified to contain sulphate-reducing bacterial rRNA genes. In summary, Clone-FISH is a simple and fast technique, compatible with a wide variety of cloning vectors and hosts, that should have general utility for probe validation and screening of clone libraries.

Cloning, Molecular↗
PubMed1997

Virtual reality support system in palliative medicine.

We have been examining the potential value of a VR system for the palliative care of cancer. We recently developed palliative care system which consists of a 100-inch-wide screen, HMD (Head-mounted display) and 8-mm video or a PC. Our goal is to use VR techniques to help alleviate a patient's stress and concern regarding their cancer during hospitalization. We can use this system to present (1) personal video movies, (2) video letters from friends and family, (3) personal video instruction about medical examinations, and (4) interactive information about their cancer using a PC-based VR system. Our preliminary results indicate that interesting VR presentations are useful for reducing stress.

Computer-Assisted Instruction↗
PubMed1981

A cost-benefit analysis of prenatal detection of Down syndrome and neural tube defects in older mothers.

Infants of older mothers have an increased risk of Down syndrome. As public awareness of this disorder increases, so does the number of women requesting prenatal diagnosis for advanced maternal age. A cost-benefit analysis was done to determine the maternal age for which screening for Down syndrome is cost-beneficial. The analysis took into account the cases of neural tube defects which would be detected "incidentally" on amniocentesis, as all amniotic fluid samples have alpha fetoprotein levels measured. British Columbia (B.C.) provides a unique opportunity for such a study: single-year maternal age risk figures for Down syndrome based on virtually complete ascertainment are available; the Department of Medical Genetics Prenatal Diagnosis Clinic is the main referral centre for the province; B.C. has a universal medicare system which facilitates the calculation of medical costs and gives all women financially equal access to prenatal diagnosis. The study concludes that prenatal screening for Down syndrome is cost beneficial for women 34 years old or older at conception. A discount rate of 14% was chosen for this analysis and the effect of such a rate on the results is discussed.

Cost-Benefit Analysis↗
PubMed1996

Prenatal screening for Down's syndrome using inhibin-A as a serum marker.

The value of measuring inhibin-A (a beta A dimer) with human chorionic gonadotrophin (total or the sub-units free a-hCG and free beta-hCG separately), alpha-fetoprotein (AFP), and unconjugated oestriol (uE3) was examined to determine the effect on the performance of serum screening for Down's syndrome between 15 and 22 weeks of pregnancy. The study was based on stored serum samples from 77 Down's syndrome singleton pregnancies and 385 unaffected singleton pregnancies, matched for maternal age, gestational age, and duration of storage of the sample, supplemented by data from 970 white women with unaffected pregnancies. Inhibin-A was elevated in the serum of women with Down's syndrome pregnancies with a median of 1.79 multiples of the median (MOM). Using the four serum markers AFP, uE3, total hCG, and inhibin-A, in addition to maternal age, 70 per cent of Down's syndrome pregnancies were detected for a 5 per cent false-positive rate compared with 59 per cent with the conventional triple test (AFP, uE3, and total hCG with maternal age). If the estimate of gestational age were based on an ultrasound scan examination, the detection rate would be 77 per cent [95 per cent confidence interval (CI) 69-85 per cent] using the four serum markers including inhibin-A, compared with 67 per cent with the triple test or 79 per cent (95 per cent CI 71-87 per cent) if marker values were adjusted for maternal weight. If the detection rate were kept at 70 per cent and the gestational age were estimated by an ultrasound scan examination, the four-marker test would reduce the false-positive rate from 6-1 per cent using the triple test to 2-9 per cent. The results were virtually the same if free beta-hCG was used instead of total hCG. The inhibin-A-based four-marker test is the most effective method of prenatal screening for Down's syndrome suitable for routine use. If the extra cost required to carry out the inhibin-A test were less than about [symbol: see text]3 per woman screened, the four-marker test including inhibin-A would be financially cost-effective.

Biomarkers↗
PubMed1990

Coexpression of the human papillomavirus type 16 E4 and L1 open reading frames in early cervical neoplasia.

Although the E4 open reading frame (ORF) of human papillomaviruses (HPV) encodes an abundant protein in cutaneous warts, the location and extent of HPV E4 expression in genital precancers, specifically those associated with HPV-16, has not been described. Expression plasmids (pATH) containing segments of the HPV-16 E4 (3401-3620) and L1 (6151-6792) open reading frames (ORFs) were induced and expressed in bacteria and the resulting fusion proteins were used to elicit antisera in rabbits. Antisera reacting to the E4 and L1 components of the fusion proteins were used to screen biopsies from 150 cervical precancers (cervical intraepithelial neoplasia) and condylomata. Six biopsies exhibiting specific immunostaining with the anti-E4 sera. Staining was cytoplasmic, and occurred virtually always in foci containing immunostaining for L1 proteins. Moreover, analysis of these 6 cases and 22 others for HPV-16 RNA by RNA-RNA in situ hybridization demonstrated a similar correlation between E4 immunostaining and the presence of abundant transcripts specific to HPV-16. These data are consistent with the hypothesis that expression of the HPV-16 E4 ORF is dependent upon viral replication and epithelial differentiation, similar to L1 expression, and that the E4 epitopes identified by the rabbit antisera may be unique to HPV-16 relative to other common cervical papillomaviruses.

Condylomata Acuminata↗
PubMed1979

The "neuroleptic" antipsychotic drugs. 1. Mechanisms of action.

The antipsychotic drugs have provided effective and relatively safe treatment of schizophrenia, paranoid illnesses, and manic-depressive conditions marked by psychotic features. These agents are sometimes called "neuroleptic," as virtually all produce signs of extrapyramidal neurologic disorders in addition to their antipsychotic actions; in part, evidently, the neuroleptic effects are an artifact of the means of screening of potential new agents. These agents have a strong and selective antagonistic action on synaptic mechanisms in the brain mediated by dopamine as a neurotransmitter. This antidopamine action almost certainly contributes importantly to their parkinsonism effect (basal ganglia) and their prolactin-elevating (hypothalamic) effect; in addition, antipsychotic actions may be mediated by antidopamine effects, possibly in limbic and other forebrain centers.

Animals↗
PubMed1995

Modulation of Saccharomyces cerevisiae DNA double-strand break repair by SRS2 and RAD51.

RAD52 function is required for virtually all DNA double-strand break repair and recombination events in Saccharomyces cerevisiae. To gain greater insight into the mechanism of RAD52-mediated repair, we screened for genes that suppress partially active alleles of RAD52 when mutant or overexpressed. Described here is the isolation of a phenotypic null allele of SRS2 that suppressed multiple alleles of RAD52 (rad52B, rad52D, rad52-1 and KlRAD52) and RAD51 (KlRAD51) but failed to suppress either a rad52 delta or a rad51 delta. These results indicate that SRS2 antagonizes RAD51 and RAD52 function in recombinational repair. The mechanism of suppression of RAD52 alleles by srs2 is distinct from that which has been previously described for RAD51 overexpression, as both conditions were shown to act additively with respect to the rad52B allele. Furthermore, overexpression of either RAD52 or RAD51 enhanced the recombination-dependent sensitivity of an srs2 delta RAD52 strain, suggesting that RAD52 and RAD51 positively influence recombinational repair mechanisms. Thus, RAD52-dependent recombinational repair is controlled both negatively and positively.

Alleles↗
PubMed1990

Fifteen years of radiological protection experience in a regional radiopharmacy.

Radiological protection experience in a regional radiopharmacy, currently handling 28.5 TBq (770 Ci) 99mTc y-1, is reviewed for the period 1974-1988. The results of personnel monitoring have shown a downward trend (by more than a factor of two) in radiation exposure of individual staff members, despite the workload per person [6000 GBq (162 Ci) 99mTc y-1] remaining virtually constant. Adequate staff selection and training contribute to the reduction in dose. A significant reduction in dose to the eyes was achieved by installing lead glass screens in the radiopharmacy work stations, and tungsten syringe shields reduced radiation dose to the hands. The use of commercially available kits for producing 99mTc radiopharmaceuticals, rather than relying on in-house preparations that require more operator handling, has also contributed to reduction in radiation exposure. Internal contamination of staff members with 125I was markedly reduced when the practice of sub-dispensing high-specific activity solutions of the radionuclide was discontinued. Annual doses from external radiation currently average less than 6 mSv (600 mrem) to the trunk, less than 7 mSv (700 mrem) to the eyes, and 50 mSv (5 rem) to the hands. Internal contamination of personnel with 125I, 131I, and 99mTc, as detected by thyroid and whole-body monitoring, contributed less than 65 mSv y-1 (6.5 rem) to the thyroid gland and less than 0.1 mSv y-1 (10 mrem) to the whole body.

Humans↗
PubMed2004

Interface delamination of layered media: acoustic spectroscopy and modal analysis.

We have developed a method of resonance ultrasound spectroscopy (RUS) to study the acoustic spectral response to interface delamination in a triple-layered rectangular parallelepiped [Al(aluminum)/polymer/Al]. Combination of laser-Doppler interferometry and the Rayleigh-Ritz approximation affected mode identification in the measured resonance spectrum. Point-contact RUS is capable of sensing a minute delamination (1.5% of total area). Modal analysis using a number of resonance modes can deduce the delamination area and location in the interface. Not only screening but also defect characterization is possible. At the same time, some resonance modes are totally insensitive to an interface imperfection. These modes are found to have virtually no strain energy arising from the bonding layer.

Journal Article↗
PubMed1987

Haemophilia A: carrier detection and prenatal diagnosis by linkage analysis using DNA polymorphism.

Restriction fragment length polymorphisms (RFLPs) within or close to the factor VIII locus are very useful for genetic linkage analysis. Such RFLPs allow a mutant allele to be tracked in a family, segregating haemophilia A even when, as is usually the case, the precise mutation causing failure to synthesise factor VIII is unknown. To date two markers tightly linked to the factor VIII locus have been described, one of which is highly polymorphic and therefore informative in most kindreds. A significant crossover rate, however, does not make diagnosis absolute. Three intragenic RFLPs have been defined, which, taken together, are informative in about 70% of women, providing virtually deterministic genetic diagnosis.

DNA↗
PubMed2003

Involvement of an SCFSlmb complex in timely elimination of E2F upon initiation of DNA replication in Drosophila.

BACKGROUND: Cul1 is a core component of the evolutionarily conserved SCF-type ubiquitin ligases that target specific proteins for destruction. SCF action contributes to cell cycle progression but few of the key targets of its action have been identified. RESULTS: We found that expression of the mouse Cul1 (mCul1) in the larval wing disc has a dominant negative effect. It reduces, but does not eliminate, the function of SCF complexes, promotes accumulation of Cubitus interruptus (a target of SCF action), triggers apoptosis, and causes a small wing phenotype. A screen for mutations that dominantly modify this phenotype showed effective suppression upon reduction of E2F function, suggesting that compromised downregulation of E2F contributes to the phenotype. Partial inactivation of Cul1 delayed the abrupt loss of E2F immunofluorescence beyond its normal point of downregulation at the onset of S phase. Additional screens showed that mild reduction in function of the F-box encoding gene slimb enhanced the mCul1 overexpression phenotype. Cell cycle modulation of E2F levels is virtually absent in slimb mutant cells in which slimb function is severely reduced. This implicates Slimb, a known targeting subunit of SCF, in E2F downregulation. In addition, Slimb and E2F interacted in vitro in a phosphorylation-dependent manner. CONCLUSION: We have used genetic and physical interactions to identify the G1/S transcription factor E2F as an SCFSlmb target in Drosophila. These results argue that the SCFSlmb ubiquitin ligase directs E2F destruction in S phase.

Animals↗
PubMed1993

[Risk of infection transmission by blood components].

OBJECTIVE: Assessment of the present risk of blood-borne infection associated with homologous blood transfusion in Central Europe with particular emphasis on HIV and HCV infections. DATA SOURCES: The relevant literature in the English and German language and the authors' data. STUDY SELECTION: No special study has been carried out for the present paper. RESULTS: The recognition of the risk for transmitting HIV by transfusion has led to a bundle of measures which have improved the safety of blood supply in Germany. A stricter donor selection as well as screening for HIV 1 and HIV 2 have reduced the risk to transmit HIV to the order of 1 per 1 million units transfused. The transmission of hepatitis B is estimated to be in the order of 1:50,000. The anti-HCV testing, introduced in 1990, has markedly reduced the transmission of HCV to less than 1:5,000 per unit as judged from our own data. A further reduction is expected by an improved HCV screening in the near future. Fatal disease from bacterial contamination is rare, with an estimated risk of one in a million units. Syphilis transmitted by transfusion is virtually not occurring anymore. However, increased efforts should continue to enhance the safety of blood, bearing in mind that a zero risk is not achievable for effective therapies. The estimation of risks is a dynamic, time-dependent value which has to be estimated for a geographically defined population for a given time period. CONCLUSIONS: The risk of transfusion-associated infection has been markedly reduced in recent years. Albeit there is a small but definitive risk, which is often overestimated. The risks have to be defined to estimate the risk/benefit ratio of the homologous as well as the autologous transfusion for the individual patient.

Blood Banks↗
PubMed1978

Occult thyroid disease in an elderly hospitalized population.

Measurements of thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH), and T3 talc uptake (T3TU) were performed on 425 hospitalized patients over 60 years of age. Unsuspected thyroid disease was found in 10 patients (2.4%); 9 were hypothyroid and 1 hyperthyroid. Another 11% of the population had abnormal T4 or TSH levels but were not proved to have thyroid disease. Repeat measurements in 10 of 40 patients with low serum T4 concentrations showed a return of the tests to normal. The low T4 levels occurred in patients who were seriously ill and were usually associated with low T3TU values. Low serum T3 concentrations were observed in 32 of the patients. Although we found TSH to be the most useful test in the diagnosis of hypothyroidism, it is a relatively expensive test and is not helpful in screening for hyperthyroidism. The present results suggest that the best single test for screening for occult thyroid disease is a serum T4 measurement. We recommend a T4 test on all hospitalized patients over age 60 years. Serum should be held in the laboratory for measurement of TSH concentration if the T4 result is below 6.5 micrograms/dl. A T3 resin or talc uptake and a serum T3 measurement should be performed to rule out hyperthyroidism if the serum T4 concentration is elevated. This regimen will identify virtually all cases of occult thyroid disease.

Age Factors↗
PubMed2006

Disability and rehabilitation in the dizzy patient.

PURPOSE OF REVIEW: This review focuses on prospective studies of vertigo and balance therapy in the past 3 years, including advances in vertigo-habituation exercises for adults, pediatric intervention, and virtual reality techniques, and, in more depth, the literature pertinent to driving motor vehicles. RECENT FINDINGS: Increased support has been generated for the efficacy of a minimal, home-based vertigo-habituation program for adults with peripheral vestibular disorders. Vestibular rehabilitation has been shown to be associated with improvements in independence and dynamic visual acuity. Community-based vestibular rehabilitation has been shown to be efficacious for selected patients, after careful screening, when trained personnel provide intervention. Vestibular rehabilitation has been incorporated into the rehabilitation program for head-injured military personnel who will be returned to duty, and multifactorial balance rehabilitation has been shown to be useful for children with hearing and balance impairments. Virtual reality techniques have made significant advances, so immersive environments have potential for rehabilitation for patients with vestibular disorders and for developing training regimens for astronauts to ameliorate some effects of exposure to microgravity. Driving skill, in general, is affected by use of benzodiazepines. For many patients with vestibular impairments driving is a particularly problematic activity of daily living. SUMMARY: Progress has been made in studies of acute care, community-based, and pediatric vestibular rehabilitation. Work on simulator-based paradigms has moved toward readiness for implementation. Studies of driving have provided some insight into the problems of these patients. More work remains to be done on all of these problems.

Activities of Daily Living↗