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Biomedical subjects

A Wolf

Publications and source records attributed to A Wolf.

At least 37 records · Page 2Linked to original sources
PubMed2004

Laryngeal electromyography in normal Brazilian population.

Quantitative analysis of normal values of motor unit action potentials duration and amplitude of muscles tireoaritenoideus (TA), cricotireoideus (CT), cricoaritenoideus lateralis (CAL), and cricoaritenoideus posterioris (CAP) was performed in 14 adult normal Brazilian volunteers. The recordings were obtained by percutaneously inserted concentric needle electrode. Different motor unit action potentials were manually selected in each muscle for quantitative computerized analysis of duration and amplitude. The mean values for duration and amplitude were respectively 3.8 ms and 413 microV for TA, 4.9 ms and 585 microV for CT 4.1 ms and 388 microV for CAL and 4.5 ms and 475 microV in CAP. There were no similar reports of normal values of motor unit action potentials in Brazilian subjects.

Action Potentials↗
PubMed2004

Laryngeal electromyography: contribution to vocal fold immobility diagnosis.

Laryngeal Electromyography (LEMG) is a diagnostic test commonly used in patients with vocal fold movement disorder. The aim of this study is to describe LEMG in patients with vocal fold immobility. A total of 55 dysphonic patients with vocal fold immobility diagnosed by laryngeal endoscopy were grouped according to probable clinical cause: 1) unknown; 2) traumatic; or 3) tumoral compression. They were submitted to LEMG by percutaneous insertion of concentric needle electrode. LEMG was conclusive in all patients and showed a majority with peripheral nerve injury. LEMG diagnosed peripheral nerve damage in 25 group 1, 12 group 2, and 11 group 3 patients. LEMG was normal in 4 patients, suggesting cricoarytenoid joint fixation. Central nervous system disorders was suggested in 2 and myopathic pattern in 1. As the major cause of vocal fold immobility is peripheral nerve damage, LEMG is an important test to confirm diagnosis.

Adolescent↗
PubMed2003

Improved test of time dilation in special relativity.

An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7Li+ ions at v=0.064c have been measured in the forward and backward direction to an accuracy of Deltanu/nu=1 x 10(-9) using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 x 10(-7) for deviations from the time dilation factor gamma(SR)=(1-v2/c2)(-1/2).

Journal Article↗
PubMed2003

Evidence for subthermal rotational populations in stored molecular ions through state-dependent dissociative recombination.

We demonstrate that the dissociative recombination of D2H+ with low-energy electrons depends on the rotational energy of the molecular ion such that highly excited ions have a larger rate coefficient than colder ones. Observations on an ion beam continuously interacting with electrons at low relative velocity indicate that excited rotational levels are preferentially depleted which, in competition with radiative heating due to blackbody radiation, provides an opportunity for controlling the rotational temperature of stored molecules.

Journal Article↗
PubMed2003

Observation of trielectronic recombination in Be-like Cl ions.

Recombination involving the core excitation of two electrons, which may be termed trielectronic recombination, has been experimentally identified for the first time. Using Cl13+ ions circulating in the TSR heavy-ion storage ring, we have observed surprisingly strong low-energy trielectronic recombination resonances, comparable to the dielectronic process. At higher electron-ion collision energies, trielectronic recombination is suppressed due to the autoionization of the triply excited intermediate state into excited final states. The formation of the intermediate state depends sensitively on configuration mixing, making trielectronic recombination a challenge to atomic-structure calculations.

Journal Article↗
PubMed2003

[Nutrient composition of the muscle, fat, and bone tissue of carcasses during the development of lambs of the merino breed with different feeding intensities].

In a developmental study of lambs, the following question was investigated: What is the influence of gender, bodyweight, and feeding intensity on the nutritional value of the carcass as well as the body tissues? This study was conducted with 108 lambs (50% males and 50% females) of the merino breed. The animals were fattened according to three feeding intensity levels ("high","medium", and "low") using varied feed concentrates and hay in their daily rations. They were slaughtered at body weights of 30, 45 or 55 kg. Six male and six female lambs were slaughtered at a bodyweight of 18 kg which was the initial weight of the fattening lambs. The left half of the slaughtered animal was carved according to the guidelines provided by the DLG (German Agricultural Society). For each cut, an examination of the meat(muscle), fatty tissue and bone/tendons was carried out and the percentages of these tissue components were determined for the whole joint. The samples of the tissues as well as the cuts were analysed for dry matter, crude protein, total fat level and crude ash. The carcasses of the male lambs showed higher protein content and lower fat levels. With increasing feeding intensity level and bodyweight, the differences in these nutritional components between the sexes rose. The muscle tissue (meat) of the lamb carcasses at the usual slaughter weight of 45 kg showed relatively low fat content (less than 10%). This was especially noticeable in carcasses of male lambs (less than 8%).

Adipose Tissue↗
PubMed2003

High interobserver variability in endosonographic staging of upper gastrointestinal cancers.

Mostly based on results of experienced examiners, endoscopic ultrasound (EUS) has been reported to be highly accurate for locoregional staging of upper gastrointestinal cancers. However, data on interobserver variability among EUS examiners, depending on their experience levels, is sparse. A study was therefore conducted to analyse well-documented videotapes of EUS examinations of 108 patients with resected cancers of the esophagus (n = 55) or stomach (n = 53) in a strictly blinded fashion by 5 examiners, all of whom were experienced in EUS (more than 300 examinations: n = 3, more than 100 examinations: n = 2). Besides the individual accuracy rates in cancer staging, a kappa-statistic was calculated to check for interobserver variability. Under the conditions described, the staging accuracy of all investigators was lower than that usually achieved under clinical routine conditions. The mean T staging accuracy was 41.1 % +/- 9.4 and 46.9 % +/- 5.4 in gastric and esophageal cancers, respectively. For N-staging the respective values were 47.9 % +/- 5.1 (stomach) and 67.7 % +/- 5.4 (oesophagus). Kappa-values were above 0.4 only in the staging of non-invasive esophagogastric tumours of the N0 and T1-category, corresponding to a fairly good agreement among the five investigators. Differences depending on experience levels could not be consistently found. Hence, it can be concluded that endosonographic cancer staging performed in a blinded manner results in a low accuracy and high interobserver variability even among experienced examiners.

Endosonography↗
PubMed2003

[Doppler sonographic estimation of normal values for flow velocity and resistance indices in renal arteries of healthy infants].

UNLABELLED: Summary. Colour coded Duplex sonography (CDI) is an important method for the judgement of renal perfusion in infancy. By means of CDI the renal artery (RA), the segmental renal arteries (SA) and the interlobar arteries (ILA) can be differentiated. By means of pulsed Doppler sonography flow parameters in renal vessels can be measured. AIM: As flow parameters in different renal arteries are age dependent, normal values of the flow velocities and resistance indices were estimated. METHOD: We investigated 147 healthy children by CDI. Children were subdivided into 4 groups: 38 infants (< 1 year), 38 toddlers (> or = 1 year and < 6 years), 37 school children (> or = 6 and < 12 years) and 34 adolescents (> or = 12 and < 18 years). All children were investigated by computersonography with a 5 or 7,5 MHz transducer. In all children blood flow was measured in the RA, SA and ILA. From the flow profile peak systolic flow velocity (Vmax), endsystolic (Ves), enddiastolic (Ved) and time average (TAV) flow velocity as well as the resistance index (RI) were measured. RESULTS: Flow velocity and resistance indices were age dependent and related to the location within the renal vascular tree. The highest flow velocity was found in the renal artery, lowest in the ILA. In infants, Vmax in the RA was 51,5 +/- 13,4, in the SA 33 +/- 8 and in the ILA 19,5 +/- 5 cm/s. In toddlers, Vmax in the RA was 71,3 +/- 13,5, in the SA 43,6 +/- 8,5 and in the ILA 28,3 +/- 6,8 cm/s. In school age children, Vmax in the RA measured 80 +/- 18, in the SA 45,5 +/- 9,1 and in the ILA 27,9 +/- 5,3 cm/s. In adolescents, Vmax in the RA was 80,7 +/- 13,7, in the SA 46,8 +/- 11,8 and in the ILA 28 +/- 6,1 cm/s. From RA to SA the other flow velocity Ves, Ved, TAV decreased about 30 % and from SA to ILA about 30 %. Flow velocity in the different renal arteries was age dependent. The lowest flow velocity was found in newborns and infants, highest in elder school children and adolescents. The flow velocity markedly increased from infancy to early childhood whereas in elder children and adolescents a slower increase of the flow velocity could be found. Every flow velocity within the RA and AIL showed a statistically significant increase with increasing age (p < 0,0001). Resistance indices decreased from the renal artery to the interlobar arteries. The RI of infants within the RA was 0,82 +/- 0,11, within the SA 0,81 +/- 0,12 and within the AIL 0,73 +/- 0,17. In toddlers the RI within the RA was 0,71 +/- 0,08, within the SA 0,67 +/- 0,07 and within the ILA 0,65 +/- 0,08. In school age children the RI within the RA was 0,71 +/- 0,09, within the SA 0,66 +/- 0,08 and the ILA 0,58 +/- 0,10. In adolescents the RI within the RA was 0,69 +/- 0,06, within the SA 0,63 +/- 0,07 and within the ILA 0,60 +/- 0,06. Additionally, resistance indices decreased with increasing age. Statistical analysis showed a significant decrease with increasing age (p < 0,0001). Highest resistance indices could be found in early infancy and in the renal arteries, lowest resistance indices were measured in school age and adolescence and in the interlobar arteries. CONCLUSION: As flow velocity and resistance indices are age dependent and dependent on the location of the sample volume in different renal arteries, both parameters have to be considered if pathological flow parameters are measured. The determination of normal values of flow velocity and resistance indices in different renal arteries facilitate the judgement of pathologic flow parameters. For comparative controls flow measurements within the renal artery and interlobar arteries should be used.

Aging↗
PubMed2002

Cloning and molecular characterization of two mosquito iron regulatory proteins.

Iron regulatory proteins (IRPs) control the synthesis of various proteins at the translational level by binding to iron responsive elements (IREs) in the mRNAs. Iron, infection, and stress can alter IRP/IRE binding activity. Insect messenger RNAs for ferritin and succinate dehydrogenase subunit b have IREs that are active translational control sites. We have cloned and sequenced cDNAs encoding proteins from the IRP1 family for the mosquitoes, Aedes aegypti and Anopheles gambiae. Both deduced amino acid sequences show substantial similarity to human IRP1 and Drosophila IRP1A and IRP1B, and all of the residues thought to be involved in aconitase activity and iron-sulfur cluster formation are conserved. Recombinant A. aegypti IRP1 binds to transcripts of the IREs of mosquito or human ferritin subunit mRNAs. No significant change in A. gambiae IRP1 messenger RNA could be detected during the various developmental stages of the life cycle, following iron loading by blood feeding, or after bacterial or parasitic infections. These data suggest that there is no change in gene transcription. Furthermore, bacterial challenge of A. gambiae cells did not change IRP1 protein levels. In contrast, IRP1 binding activity for the IRE was elevated following immune induction. These data show that changes in IRP1/IRE binding activity occur as part of the insect immune response.

Aedes↗
PubMed2002

You get what you expect? A critical appraisal of imaging methodology in endosonographic cancer staging.

BACKGROUND AND AIMS: After an initial period of excellent results with newly introduced imaging procedures, the accuracy of most imaging methods declines in later publications. This effect may be due to various methodological factors involved in the research. Using the example of endoscopic ultrasound (EUS), this study aimed to elucidate one of the factors possibly concerned--namely, the extent to which the examiners are adequately blinded. METHODS: Well documented videotapes of EUS examinations of 101 patients with resected tumours of the oesophagus (n=32), stomach (n=33), or pancreas (n=36) were evaluated in three different ways: firstly, retrospective analysis under routine clinical conditions; secondly, evaluation of EUS videotapes in a strictly blinded fashion; and thirdly, evaluation of the same videotapes but with additional information from the video endoscopic appearance (oesophageal/gastric cancer) or from computed tomography results (pancreatic cancer). Histopathological T staging was used as the reference method. RESULTS: The accuracy of EUS in T staging was 73% under routine conditions. This value fell significantly to 53% for the blinded evaluation but increased again to 62% for the unblinded evaluation. The sensitivity of staging T1/T2 tumours was 72% (routine EUS), 59% (blinded EUS), and 70% (unblinded EUS). The respective values for advanced tumours were 85%, 74%, and 72%. CONCLUSIONS: The accuracy of EUS for T staging in clinical practice appears to be lower than has previously been reported. In addition, blinded analysis produced significantly poorer results, which improved when another test was added. It may be speculated that better results with routine EUS obtained in a clinical setting are due to additional sources of information.

Digestive System Neoplasms↗
PubMed2002

Mapping of a further locus for X-linked craniofrontonasal syndrome.

Craniofrontonasal syndrome is a rare dysostosis syndrome with an unusual pattern of X-linked inheritance, because males are usually not or less severely affected than females. Previously, a CFNS locus has been localised in Xp22. We report on a haplotype analysis in a German CFNS family, mapping the CFNS locus to the pericentromeric region of the X chromosome. This discrepancy can be explained by locus heterogeneity. Furthermore, random X inactivation could be demonstrated in affected females. The most plausible interpretation for this unusual pattern of X-linked inheritance is metabolic interference. Consequently, we propose that the CFNS gene escapes X inactivation.

Cell Line↗
PubMed2001

Search for the familon via B(+/-) --> pi+/-X(0), B(+/-) --> K(+/-)X(0), and B(0) --> K(0)(S)X(0) decays.

We have searched for the two-body decay of the B meson to a light pseudoscalar meson h = pi(+/-),K+/-,K(0)(S) and a massless neutral feebly interacting particle X(0) such as the familon, the Nambu-Goldstone boson associated with a spontaneously broken global family symmetry. We find no significant signal by analyzing a data sample containing 9.7x10(6) BBbar mesons collected with the CLEO detector at the Cornell Electron Storage Ring, and set 90% C.L. upper limits italicB(B(+/-) --> h(+/-)X(0)) = 4.9x10(-5) and italicB(B(0) --> K(0)(S)X(0)) = 5.3x10(-5). These limits correspond to a lower bound of approximately 10(8) GeV on the family symmetry breaking scale with vector coupling involving the third generation of quarks.

Journal Article↗
PubMed2001

Branching fraction and photon energy spectrum for b --> s gamma.

We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, = 2.346+/-0.032+/-0.011 GeV, and - (2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.

Journal Article↗
PubMed2001

Hadronic mass moments in inclusive semileptonic B meson decays.

We have measured the first and second moments of the hadronic mass-squared distribution in B-->X(c)l nu, for P(lepton)>1.5 GeV/c. We find = 0.251+/-0.066 GeV(2), <(M(2)(X)- )(2)> = 0.576+/-0.170 GeV(4), where M macro(D) is the spin-averaged D meson mass. From that first moment and the first moment of the photon energy spectrum in b-->s gamma, we find the heavy quark effective theory parameter lambda(1) (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) to be -0.24+/-0.11 GeV(2). Using these first moments and the B semileptonic width, and assuming parton-hadron duality, we obtain absolute value of V(cb) = 0.0404+/-0.0013.

Journal Article↗
PubMed2001

First measurement of gamma(D*(+)).

We present the first measurement of the D*(+) width using 9/fb of e(+)e(-) data collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method uses advanced tracking techniques and a reconstruction method that takes advantage of the small vertical size of the Cornell Electron-positron Storage Ring beam spot to measure the energy release distribution from the D*(+)-->D(0)pi(+) decay. We find gamma(D*(+)) = 96+/-4 (stat)+/-22 (syst) keV. We also measure the energy release in the decay and compute Delta m identical with m(D*(+))-m(D(0)) = 145.412+/-0.002 (stat)+/-0.012 (syst) MeV/c(2).

Journal Article↗
PubMed2001

Morphometric study of the human lumbar spine for operation-workspace specifications.

STUDY DESIGN: The anatomy of the lumbar vertebrae of 55 patients was measured by use of data provided by computed tomography. On the basis of these measurements, the location of puncture points and the orientation of the surgical instruments for pedicle, vertebral body, and disc entry points were calculated for open as well as percutaneous surgery. OBJECTIVE: Normal anatomic variations of the lumbar spine were investigated to define the workspace for several spinal procedures and to define the workspace of a robot designed to guide the physician during those procedures. SUMMARY OF BACKGROUND: Several comprehensive studies of vertebrae dimensions have been conducted in the past, but they lack several dimensions that are needed to determine the exact location of the entry point and orientation of the tool, in particular when a computerized guidance system is used. METHODS: Fifty-five spinal columns (L1-L5, total 250 vertebrae) were measured by computed tomography. These data provide geometric relations that determine entry points and tool orientations for different spinal interventions. RESULTS: The workspace for spinal operations was defined on the basis of anatomic data taken from computed tomography scans. The data included 15 measurements for each vertebra that defined its shape. The processed data provided puncture points for several spinal procedures in both open and percutaneous surgery. CONCLUSIONS: This study provides additional information on vertebral structure needed to calculate accurately the entry point and tool orientation in various spinal procedures. These statistical data are also valuable for model and implant designs and for workspace specifications for a robot-assisted surgery system.

Adult↗
PubMed2001

Nontruncating APC germ-line mutations and mismatch repair deficiency play a minor role in APC mutation-negative polyposis.

Familial adenomatous polyposis, an autosomal-dominantly inherited colorectal cancer predisposition syndrome, is caused by germ-line mutations in the adenomatous polyposis coli (APC) gene. Despite the use of different screening methods, studies worldwide fail to identify APC mutations in 20-50% of all familial adenomatous polyposis patients (APC mutation-negatives). In this study, missense mutations in the coding region of the APC gene, which would have been missed by the protein truncation test, as well as mutations in the APC promoter and the 3' untranslated region, were determined by the single nucleotide polymorphism discovery assay and direct DNA sequencing in 31 mutation-negative polyposis patients. Seventeen gene alterations were identified, whereof four (12.9%) represent possibly pathogenic germ-line mutations: silent A290T (promoter) and A8822G (3' untranslated region) as well as missense R99W and E1317Q (coding region). The 27 remaining, truly APC mutation-negative polyposis patients displayed a significantly later age at diagnosis compared with APC mutation carriers (46.1 versus 35.2 years; P < 0.01). APC mutation-negative individuals with >100 colonic polyps were more likely to present with extracolonic disease (P < 0.05) than those with <100. Assessment of microsatellite instability (MSI), a hallmark of mismatch repair deficiency, in 68 tumors from 21 truly APC mutation-negative patients, identified 4 (5.9%) unstable tubulo-villous adenomas (3 MSI-High and 1 MSI-Low), stemming from 4 (19%) unrelated individuals and likely to be caused by hMLH1 promoter hypermethylation. In conclusion, only a small proportion of APC germ-line mutation carriers is missed by the protein truncation test, and mismatch repair deficiency does not seem to substantially contribute to tumor development in APC mutation-negative polyposis patients.

3' Untranslated Regions↗