Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “extreme rays”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed2005

Imaging findings of Kimura's disease in the soft tissue of the upper extremity.

OBJECTIVE: The objective of our study was to describe the imaging findings of Kimura's disease in the soft tissue of the upper extremity. CONCLUSION: Kimura's disease should be considered as a possible diagnosis when a partially or poorly defined subcutaneous mass of high signal intensity on T1- and T2-weighted images with homogeneous enhancement, surrounding subcutaneous edema, and internal flow voids is seen in the medial epitrochlear region in an Asian person, especially if accompanied by peripheral eosinophilia.

Adolescent↗
PubMed1998

Effect of hand dominance on bone mass measurement in sedentary individuals.

The aim of this study was to determine in healthy sedentary subjects the effect of hand dominance on side-to-side difference in bone area and bone mass for upper and lower extremities. Dual-energy X-ray absorptiometry (DXA) measurements of both forearms and hips were performed on 193 right-handed and 20 left-handed subjects as determined by self-report. Scan acquisition and scan analyses were performed by one investigator, but all scan pairs were independently assessed for symmetry of positioning and movement artifacts by three investigators. Results show that DXA measurements between sides may be highly correlated regardless of the symmetry of the scan pair. However, asymmetric DXA scan pairs may have more than twice the side-to-side difference found in symmetric DXA scan pairs at the hip. Side-to-side differences between subregions were greater than the differences between measurements at the total radius, ulna, or hip. For symmetric pairs of DXA scans, the dominant forearm has significantly higher bone area and bone mineral content (BMC). Bone mineral density (BMD) was significantly higher only in the ulna of the dominant forearm. However, the nondominant forearm has higher values than dominant forearm in at least one DXA measurement in >24% of the subjects. There were no significant differences in any DXA measurements between hips, and higher DXA measurements did not occur significantly more frequently at the hip corresponding to the dominant hand. We conclude that healthy sedentary subjects tend to have proportionally higher bone area and BMC in the dominant forearm that results in similar BMD between dominant and nondominant forearms. This relationship does not appear to be applicable to measurements at the hip. In addition, there is a significant proportion of subjects with higher bone area and BMC in the nondominant extremities. Thus, in sedentary subjects, the consistency in the use of same extremity and the consistency in scan acquisition techniques and scan analyses is of greater importance than the selection of an extremity based on hand dominance in DXA studies.

Journal Article↗
PubMed1994

Ultramicroanalysis of dental plaque films by total reflection X-ray fluorescence.

Microgram quantities of dental plaque were taken near amalgam fillings, gold crowns and intact teeth. Such extremely small samples can be analysed by total reflection X-ray fluorescence (TXRF), a fairly new variant of energy dispersive X-ray fluorescence (EDXRF). More than sixty samples were examined directly without chemical pretreatment. Fifteen elements of interest were detected simultaneously within a wide range of mass fraction and with detection limits of several mg/kg. A significant correlation of the Hg-accumulation in plaque and the amalgam fillings was established. Near these fillings Hg mass fractions can reach a level of 300 mg/kg. The results for other elements, e.g. Au, are less significant.

Computer Simulation↗
PubMed2004

XAFS imaging of Tsukuba gabbroic rocks: area analysis of chemical composition and local structure.

Gabbroic rocks were collected at Mount Tsukuba in Japan, and their XAFS images were studied using a projection-type X-ray fluorescence (XRF) microscope, which is a powerful new tool recently developed for extremely rapid imaging. The instrument employs a grazing-incidence arrangement in order that primary X-rays illuminate the whole sample surface, as well as parallel-beam optics and an extremely close geometry in order to detect XRF by a high-performance X-ray CCD system with 1024 x 1024 pixels. The XRF image indicated that black amphibole and white feldspar, both of which are typical mineral textures of the rock, contain iron. The origin has been suggested to be several small yellowish-brown minerals contained there. The XAFS imaging has been carried out by repeating the exposure of XRF images during the energy scan of the primary X-rays. It has been found that the structure is qualitatively close to that of olivine, and the main differences found in both areas can be explained as a difference in iron and magnesium concentration, i.e. the mixed ratio of forsterite (Mg(2)SiO(4)) and fayalite (Fe(2)SiO(4)). The feasibility of the present XAFS imaging method has been demonstrated for realistic inhomogeneous minerals.

Altitude↗
PubMedDate not supplied

Structural polymorphisms of rough mutant lipopolysaccharides Rd to Ra from Salmonella minnesota.

The structural polymorphisms of rough mutant lipopolysaccharides (LPS) Rd, Rc, Rb, and Ra from Salmonella minnesota (strains R4, R7, Rz, R5, R345, and R60, respectively) were investigated as a function of temperature, water content, and Mg2+ concentration. The gel to liquid crystalline (beta<==>alpha) phase transition temperature (Tc) and the state of order within each phase were measured by Fourier transform infrared spectroscopy. The amount of bound water was determined by differential scanning calorimetry and the three-dimensional structures in each phase state were characterized by synchrotron radiation X-ray diffraction. The results indicate an extremely complex dependence of the structural behavior of LPS on ambient conditions. The beta<==>alpha acyl chain melting temperatures at high water contents (95-97%), Tc = 31 to 32 degrees C for LPS Rd, 33 to 35 degrees C for LPS Rc to Rb, and 36 degrees C for LPS Ra, increase with decreasing water content and in the presence of Mg2+ cations with a concomitant broadening of the transition range. Below 30 to 50% water content, no distinct phase transitions can be observed. These effects are most pronounced for LPS with the shortest sugar chains. Below 50% water content, only lamellar structures can be observed in the temperature range 5 to 80 degrees C, independent of the Mg2+ concentration. Above 50% water concentration, for large [LPS]:[Mg2+] molar ratios the predominant structure above Tc is nonlamellar; for smaller [LPS]:[Mg2+] molar ratios a superposition of lamellar and nonlamellar structures is found. For all LPS Rd to Rb at low Mg2+ concentrations, the phase transition is connected with a change in the three-dimensional structure from lamellar or mixed lamellar/nonlamellar to a pure nonlamellar, probably cubic structure. The tendency to form non-lamellar structures decreases with the length of the core oligosaccharide. At an equimolar ratio of [LPS] and [Mg2+] a multibilayered organization is observed. Some of the nonlamellar structures are cubic phases with periodicities between 12 and 16 nm. The molecular dimensions of the single endotoxin molecules in the absence and the presence of external water are estimated from the different lamellar periodicities, including those of free lipid A and deep rough mutant LPS Re. These observations are discussed with respect to the biological importance of LPS as a potent inducer of biological effects in mammals.

Bacterial Toxins↗
PubMed1975

[Misplaced implantation of a pacemaker electrode in a coronary vein].

The wrong implantation of pacemaker electrodes into a coronary vein is in most cases accidentally diagnosed when thoracic X-ray pictures are made in two planes. It is to be excluded not with certainly in the sagittal ray-path of the thoracic X-ray picture and in the ECG of the extremities. The diagnostic criteria for the recognition of a false position are the end of the electrode which is in the frontal ray-path directed dorsally to the spine and a right bundle branch block in the ECG existing since implantation. Pacemaker-synchronous contractions of the diaphragm as well as an increased already at the time of implantation stimulus threshold may be references. Description of an own observation with an up to now long-term stimulation through a coronary vein without complications lasting 15 months, in which a correction of the position is not regarded as necessary due to the regular function of the pacemaker.

Aged↗
PubMed1994

A vibrational spectroscopic study of the self-association of polyinosinic acid and polyguanylic acid in aqueous solution.

We have studied by Raman and ir spectroscopy the structure of self-associated polyinosinic acid and polyguanylic acid in aqueous solution. The results are consistent with the formation of a four-stranded complex, which melts cooperatively near 60 degrees C in the case of poly(I) in the presence of K+ ions. The conformation of the ribose in both systems is mixed C2'-endo/C3'-endo, giving a structure that is intermediate between the extremes proposed previously from x-ray diffraction studies. Characteristic Raman bands for the C2'-endo ribose conformation in polyribonucleotides are identified. The four-stranded structure of poly(I) appears to be very flexible, with approximately 15% of the tetrameric segments being disrupted and approximately 30% of the ribose units adopting a disordered conformation prior to melting. This disordering process increases to approximately 75% above the melting transition, with the remaining approximately 25% of the ribose units keeping an ordered C2'-endo or C3'-endo conformation.

Nucleic Acid Conformation↗
PubMedDate not supplied

[Effect of X-ray contrast medium on peripheral circulation, arterial blood flow and venous capacity in the lower extremities during phlebography (author's transl)].

The influence of contrast medium (20 ml Meglumine Diatrizoate 65%; Angiografin) on peripheral circulation was studied after injection into the vena saphena magna in 12 patients (mean age 40.5 years) with markedly varicose veins. Pneumatic segment-plethysmography and "mercury-in-rubber" strain-gauge-plethysmography were used to investigate local and systemic effects of contrast medium on intravascular basic volume and pressure-dependent venous capacity. Heart rate was controlled by Ecg-monitoring, venous blood pressure by means of a Schwarzer pressure transducer, and peripheral blood flow by means of pneumatic segment-plethysmography. In addition peripheral vascular resistance was calculated. Local effect of contrast medium on large veins was a small insignificant increase (2.2%) of venous capacity. However, there was a significant increase of additional 10% after recirculation (2 P less than 0.01). Intravascular basic volume showed a significant increase as well (2 P less than 0.01). In addition the calculated increase of total intravascular volume--represented by intravascular basic volume plus venous capacity--was 16.3% related to an intravenous pressure of 70 mm Hg. According to these findings, 20 ml contrast medium enlarges the blood volume dumping into the legs with postural changes by approximately 270 ml. Arterial inflow increased significantly (2P less than 0.01) by 40% after contrast injection, whereas mean arterial blood pressure decreased simultaneously. Consequently a reduction of peripheral vascular resistance of 32% was calculated. The neglectable local effect of contrast medium on pressure-dependent venous capacity is probably due to the markedly reduced distensibility of varicose veins. In contrast a striking effect of contrast medium is observed after recirculation, which is felt to be due to a general vasodilatation of capillary vessels and pre- and postcapillary resistance vessels.

Adult↗
PubMed1999

Aluminum-induced osteogenesis in osteopenic rats with normal renal function.

Previous studies have shown a different effect of aluminum (Al) on bone metabolism in animals with chronic renal failure and conversely, positive osteogenic effects in animals with normal renal function. The aim of this study was to evaluate the effect of aluminum on bone metabolism in osteopenic rats. We studied male Wistar rats with severe osteopenia induced by adding NH4Cl (2%) to the drinking water over a 6-month period. The rats were divided into two groups and followed for 4 months. The Aluminum group (G1) received AlC13 intraperitoneally (10 mg/kg/5 days/week) (n = 8); the Control group (G2) did not receive any treatment after stopping the administration of NH4Cl (n = 5). In all animals we measured biochemical markers (serum Ca, P, Cr, Al, osteocalcin, hydroxyproline) as well as bone mineral density and bone histomorphometry (BV/TV, CTh, ObS/BS, OTh, and NOc/TV). Bone aluminum content, measured by atomic absorption spectrometry, was 101.6 +/- 13 microg/g in the Al overloaded group and 1.31 +/- 0.14 in controls. Bone mineral density, evaluated by dual X-ray absorptiometry (DXA) at the proximal extremity of the tibia was significantly higher in G1 (0.292 +/- 0.01 g/cm2 versus 0. 267 +/- 0.02 g/cm2). No significant differences were found between the biochemical markers. In the histomorphometric parameters we observed significant differences in G1 compared with G2: an increase in BV/TV (18.59 +/- 5.6 versus 7.69 +/- 3.08%) and in CTh (0.52 +/- 0.06 versus 0.36 +/- 0.07 mm) with a moderate increment of the osteoid thickness (14.05 +/- 4.72 versus 5.25 +/- 0.9 microm) (P < 0. 05). Changes in others parameters and the relationship between biochemical parameters of bone remodeling, Al, and histology were analyzed. These findings indicate that in rats with normal renal function, Al is able to induce bone formation even when osteopenia is present.

Aluminum↗
PubMed2005

Fetal exposure to sodium valproate associated with Baller-Gerold syndrome: case report and review of the literature.

CASE REPORT: We report three patients with a history of maternal valproate use during pregnancy who presented with a combination of metopic suture synostosis and upper limb malformations, which could be diagnosed as Baller-Gerold syndrome (BGS). The patients underwent surgical treatment for the craniofacial deformity, during which standard frontocranial reconstruction was performed. REVIEW OF THE LITERATURE: Only 32 patients have been reported in the world literature and these cases support the emerging view that BGS is not a distinct syndrome, but should instead be considered to be an heterogeneous phenotype with variable etiology. CONCLUSIONS: Our case series suggests for the first time that fetal sodium valproate exposure may also cause this phenotype.

Craniosynostoses↗
PubMed2004

Whiplash injury: is there a role for electromyographic studies?

INTRODUCTION: This retrospective study was undertaken to assess the value of carrying out baseline and follow-up electromyography (EMG) for patients with whiplash-associated disorders (WAD, grades I and II) after they had undergone rear-end car collisions, and to determine if there is any agreement with clinical and imaging (CT and MRI) findings. MATERIALS AND METHODS: We carried out a retrospective review of 330 patients seeking compensation after rear-end car collisions. The treating physician referred all patients for EMG studies in the post-injury follow-up period and for additional CT scans and MRIs. All patients underwent physical and X-ray examination by the senior author (SD), and 75 patients with persistent radicular complaints were referred again for EMG studies. The results of the association between patient complaints, clinical examination, and EMG, CT and MRI studies are reported. RESULTS: We sought but failed to find any correlations between 354 EMG results with those of 278 CT scans and 75 MRIs. Both subjective complaints and early vs late EMG abnormalities showed statistical agreement and persistency of findings only at disc level C7/D1. CONCLUSIONS: Our data indicate that follow-up EMG studies for patients with WAD do not contribute any useful information for patient management.

Accidents, Traffic↗
PubMed2004

Gait analysis of sporadic and hereditary spastic paraplegia.

OBJECTIVES: Sporadic (SSP) and hereditary spastic paraplegias (HSP) are clinically and genetically heterogeneous disorders, which are characterised by a slowly progressive spastic paraparesis. Initial symptoms and the rate of progression are variable even among members of the same family. Spastic paraparesis is the major and most disabling clinical symptom and was assessed with gait analysis using a three-dimensional infrared movement analysis system. METHODS AND RESULTS: 22 patients with clinically and/or genetically confirmed SSP/HSP were compared with age-matched control subjects. Significantly lower values were found for gait velocity, stride length, step height and the range of motion of the knee-angle. The gait pattern is characterised by a severe spasticity of both legs with only mild paresis. The balance-related gait parameters show a broad-based gait without inwardly rotated feet. No correlation was found between disease duration and the severity of the gait disorder and the central motor conduction time to the leg muscles and the abnormal gait parameters. The gait pattern did not differ between the 7 SSP cases and the 15 HSP cases. CONCLUSIONS: We conclude that three-dimensional gait analysis can uncover specific features of such rare gait disorders, and may be used as an objective tool to quantify the impairment of gait parameters in patients with SSP/HSP and thus can be used to monitor disease progression and the effect of therapeutic interventions.

Adult↗
PubMedDate not supplied

Severe bone changes in a case of Hutchinson-Gilford syndrome.

The Hutchinson-Gilford progeria syndrome (HGPS) is a very rare, but well known inherited condition of uncertain etiology in which features of premature and accelerated aging are mixed with those of delayed maturity and immaturity. Appearance at birth and birth weight are usually normal but growth typically slows after 1 year. All organ systems undergo degeneration to such an extent that the patient resembles an old man or woman. Short stature, micrognatia, alopecia, sculptured nose, prominent scalp veins, loss of subcutaneous fat, prominent joints, hyperlipidemia and early arteriosclerosis characterize the syndrome. Skeletal compromise includes hypoplasia and dysplasia, persistent open fontanelles, severe osteolysis and pathological fractures. There are no intellectual deficits in patients with this syndrome, and intelligence is unaffected. The life span in progeria is shortened by early arteriosclerosis. In this case, we review the characteristics of the severe osteolytic compromise in distal arms and limbs and bone deformities in a case of an 8-year-old girl, who was admitted to our hospital with short stature and loss of hair. On examination, the child had the major clinical criteria for HGPS as well as severe alterations in osteogenesis, including craniofacial disproportion, short and sculptured nose, delayed dentition, severe scoliosis, clavicular deformity and asymmetrical and hypoplastic arms and legs. Generalized osteopenia and severe osteolytic compromise in distal extremities were found by X-ray examination. In summary, we report the case of an 8-year-old girl who meets the diagnostic criteria for HGPS with severe involvement of her bones and joints with a review of the current literature and a possible therapeutic approach.

Alopecia↗
PubMed1998

The radiographic analysis of web height.

Web creep is a common complication following surgical release of syndactyly. Currently, normal web height has not been objectively determined, which prevents accurate analysis of the degree of web creep after surgery. The purpose of this study was to design a technique to reproducibly measure web height and to define the standard web height in a control population. Four hundred thirty-seven standard left posteroanterior hand x-rays of children without any upper extremity pathology were evaluated. Web height was measured as a relative ratio to digital length using standard landmarks. All measurements were tabulated according to gender, age, and web space. Statistical analysis was performed to determine the reliability of this technique and to delineate any differences between web space, gender, and age. There was no significant intraobserver or interobserver difference and web height was similar in males and females. There was a significant difference between web height with respect to web location and age. Normal ranges of web height with regard to age and web position were determined and plotted as graphs. Using this measurement method, web creep can be evaluated and comparison studies of different surgical techniques performed.

Adolescent↗
PubMed2005

Quantum interference during high-order harmonic generation from aligned molecules.

High-order harmonic generation (HHG) from atoms and molecules offers potential application as a coherent ultrashort radiation source in the extreme ultraviolet and soft X-ray regions. In the three-step model of HHG, an electron tunnels out from the atom and may recombine with the parent ion (emitting a high-energy photon) after undergoing laser-driven motion in the continuum. Aligned molecules can be used to study quantum phenomena in HHG associated with molecular symmetries; in particular, simultaneous observations of both ion yields and harmonic signals under the same conditions serve to disentangle the contributions from the ionization and recombination processes. Here we report evidence for quantum interference of electron de Broglie waves in the recombination process of HHG from aligned CO2 molecules. The interference takes place within a single molecule and within one optical cycle. Characteristic modulation patterns of the harmonic signals measured as a function of the pump-probe delay are explained with simple formulae determined by the valence orbital of the molecules. We propose that simultaneous observations of both ion yields and harmonic signals can serve as a new route to probe the instantaneous structure of molecular systems.

Journal Article↗
PubMed2002

Destructive osteoblastoma of the cervical spine with complete neurologic recovery.

STUDY DESIGN: Case report. OBJECTIVE: To describe a patient with a large tumor lesion of the 6th vertebrae affecting surrounding soft tissue, and symptoms of cord compression. Histologic diagnosis indicated a destructive osteoblastoma following dorsal and anterior resection and internal fixation. SETTING: University Hospital, Germany. METHODS: A 23-year old male patient was admitted with a 2-month history of increasing upper extremity weakness and pain. X-ray and MRI indicated massive involvement of the anterior and posterior elements of the 6th vertebrae with a large soft tissue mass. Following emergency decompression and dorsal stabilization, the pathologic investigation revealed a destructive osteoblastoma. Subsequent dorsal and anterior resection with internal fixation were performed. RESULTS: The patient initially presented with symptoms of beginning paraplegia of C6/7. According to the neurologic classification of spinal cord injury, motor function score was 56 and sensory function score 83. After emergency dorsal decompression and internal fixation with Luque-Instrumentation he showed increasing neurological recovery. Complete neurological recovery was achieved at 2 and 12-months postoperatively, following secondary dorsal and anterior resection of the tumor and internal fixation with bone cement (PalacosR) and Harms-cage. Radiologic signs of local recurrence were identified 1 year postoperatively. CONCLUSION: Osteoblastoma of the cervical spine is rare. Patients often present with severe neurological symptoms due to significant tumor mass. Complete resection is necessary to regain full recovery, to prevent recurrence and, in some cases, malignant transformation.

Adult↗