Comparison and combination of the starch-gel and filter-paper electrophoretic methods applied to human sera: two-dimensional electrophoresis.
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Blood Proteins↗
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Pathognomonic radiological signs for predicting prognosis in patients with chronic atlantoaxial rotatory fixation.
OBJECT: The authors conducted a study to assess the correlation between radiological features and clinical courses in patients with chronic atlantoaxial rotatory fixation (AARF) and to determine diagnostic imaging signs for predicting prognosis. METHODS: There were 24 patients (eight boys and 16 girls) whose mean age was 7.8 years (range 4-14 years) and in whom AARF was diagnosed. The mean follow-up duration was 3.7 years (range 5 weeks-12 years). There were two groups of patients: 15 patients who visited the hospital less than 8 weeks after symptom (torticollis) onset comprised the acute group, and nine patients in whom the diagnosis of AARF was established later than 3 months after symptom onset comprised the chronic group. The chronic group was divided into two subgroups: those in whom the closed reduction could be achieved and those in whom it could not. Clinical data and radiographic studies, including plain radiographs and plain and three-dimensional (3D) computed tomography (CT) reconstructions, were reviewed retrospectively. A deformity of the superior C-2 facet joint was frequently observed in the group of patients with chronic AARF (p < 0.0001). This sign represented a risk factor for recurrent dislocation (p = 0.0003, Fisher exact test). Prominent lateral inclination of C-1 was an impeding factor for reduction of chronic AARF (p < 0.0001, analysis of variance with Fisher post hoc test). Greater than 20 degrees of lateral inclination of the atlas indicated an irreducible subluxation (p = 0.0023, Fisher exact test). CONCLUSIONS: Both facet joint deformity and lateral inclination observed on 3D CT reconstructions can be useful signs to predict the prognosis and the treatment of choice in patients with chronic AARFs.
Adolescent↗
Strain compounding: a new approach for speckle reduction.
A new compounding technique for reducing speckle brightness variations is proposed. This method exploits the decorrelation between signals under different strain states. The different strain states can be created using externally applied forces such as the ones used in sonoelastography. Such forces produce three-dimensional tissue motion. By correcting only the in-plane (i.e., axial and lateral) motion, the images under different strain states have similar characteristics except for speckle appearance caused by the uncorrected out-of-plane (i.e., elevational) motion. Additional speckle decorrelation is also introduced through tissue motion correction caused by the change of effective in-plane sample volume geometry. Therefore, these images can be combined for speckle reduction with less degradation in in-plane spatial resolution than conventional approaches. In this paper, three-dimensional tissue motion under various strain conditions were simulated. It was found that significant speckle decorrelation existed at strains achievable in some clinical situations. Experiments were also conducted to test efficacy of this approach. Pulse-echo data from a gelatin-based phantom were acquired using a 5-MHz, single crystal transducer, and both conventional and compound B-mode images were formed. Results indicated that speckle brightness variations were reduced, and detectability of low contrast objects was enhanced. Performance limitations and fundamental differences between the proposed technique and existing techniques are discussed.
Acoustics↗
Three-dimensional modelling of mercury cycling in the Gulf of Trieste.
The Gulf of Trieste (Northern Adriatic) is subject to mercury pollution from a former mercury mine in Idrija, located along a river which transports mercury-contaminated sediments into the Gulf. Concentrations in suspended and bottom sediments are up to two orders of magnitude higher than in the central and southern Adriatic. Extensive research has been carried out on measurements and modelling of the transport and fate of mercury in the Gulf. Two- and three-dimensional models have been developed to include the influence of the significant advective transport due to currents. Wind, thermohaline forcing, and the Soca river momentum are the most important forcing factors. A two-dimensional model simulated the transport of non-methylated and methylated mercury in dissolved, particulate and plankton fractions. Mercury processes included the input of atmospheric mercury, sedimentation, reduction, methylation and demethylation. The model simulations gave basically what were proper trends of the phenomena; quantitatively the measured and computed results are mainly within a factor of three. To simulate the non-uniform distribution of parameters over the depth, an existing three-dimensional (3D) hydrodynamic and transport-dispersion (TD) model, PCFLOW3D, was adapted and applied. As it was found that most mercury transport is related to suspended sediment particles, a new 3D sediment transport module was also developed and included in the model. Three cases are presented: one describing the simulation of TD of dissolved total mercury; another the simulation of the TD of particulate mercury in the Gulf during a river flood; and the third simulating sediment transport in the Gulf during a period of strong ENE wind. Comparison with measurements was only partly possible, but mainly the computed and measured results were within a factor of two and proper trends of the phenomena were obtained by the simulations. The combination of modelling and measurements has resulted in some interesting conclusions about the phenomenon of the transport and fate of mercury in a coastal sea.
Animals↗
Computer-assisted fluoroscopy-based reduction of femoral fractures and antetorsion correction.
OBJECTIVE: Intra-operative fluoroscopy is a valuable tool for visualizing underlying bone, implant, and surgical tool positions in orthopedics. It has brought about the minimally invasive surgical technique of intramedullar nailing to fix femoral shaft fractures. However, the limited field of view and two-dimensional property of fluoroscopic images aggravate intra-operative control of surgical parameters. The purpose of this article is to introduce a surgical navigation system based on fluoroscopy that provides missing information for the procedure of femoral fracture fixation. MATERIALS AND METHODS: Optoelectronic markers are placed on a surgical drill, involved bone fragments, the femoral nail, and the fluoroscope to track their positions. Projection properties of the fluoroscope are acquired through an initial precalibration. The relative positions of bone fragments, implants, and surgical tools are displayed superimposed simultaneously and in real time on multi-planar intra-operative fluoroscopic images. This is achieved by computer simulation of X-ray projections that have taken place with acquisition of the fluoroscopic images. In addition, a method has been developed that allows contactless measurement of three-dimensional anatomic landmarks, based on their representation in fluoroscopic images. In combination with optoelectronic tracking, this enables dynamic calculation of important surgical parameters such as femoral antetorsion. RESULTS: A pilot surgery showed that fracture reduction can benefit from the developed computer-assisted method. An in-vitro study on computer-assisted measurement of femoral antetorsion demonstrated the high degree of precision of this technique.
Bone Nails↗
Characterization of left ventricular mechanical function during arrhythmias with two dimensional echocardiography. I. Premature ventricular contractions.
Two dimensional echocardiography was applied experimentally in the closed chest dog to quantitate left ventricular function during and immediately after single premature ventricular contractions induced through threshold stimulation at the apex. Coupling intervals were varied over a range from 35 to 85 percent of the R-R interval during normal sinus rhythm (920 to 980 ms). The quality of tomographic echocardiographic images during premature as well as postextrasystolic beats was found to be satisfactory for quantitating short axis section areas at end-diastole and end-systole. A systolic fractional area change was computed from two dimensional echocardiographic measurements to characterize mid ventricular cardiac function, which correlated significantly with peak left ventricular pressure and maximal first derivative of left ventricular pressure (dP/dt). Marked shortening of coupling intervals reduced fractional shortening during premature systole and enhanced the degree of potentiation during the postextrasystolic beat. By contrast, premature beats with relatively long coupling intervals caused less reduction in contraction and only minor postextrasystolic potentiation. Systolic shortening of left ventricular length as well as transverse diameters were studied in a two dimensional echocardiographic long axis cross section. During long coupling intervals contraction was normal except for distinct regional systolic outward "bulging" in the apical region. In contrast, short coupling intervals were associated with a more significant generalized derangement of ventricular wall motion during systole. It is concluded that the two dimensional echocardiographic method can be used to portray and quantitate global as well as regional left ventricular function during disturbances of cardiac rhythm.
Animals↗
Computer-aided reduction of zygomatic fractures.
Reconstruction of the craniofacial skeleton after traumatic injury relies on immediate adjacent nondisplaced bone for restoration of contour. In complex fractures, neighboring bone may be lost or significantly fragmented, leaving little guidance to the 3-dimensional skeletal architecture. Recently, image guidance systems have been used in neurosurgery and sinus and spine surgery for intraoperative corroboration using preoperative radiologic images. We report the intraoperative use of an image guidance system for real-time localization of displaced facial skeletal segments during reduction and internal fixation.
Aged↗
Aldose and aldehyde reductases: correlation of molecular modeling and mass spectrometric studies on the binding of inhibitors to the active site.
Aldose and aldehyde reductases are monomeric NADPH-dependent oxidoreductases that catalyze the reduction of a wide variety of aldehydes and ketones to their corresponding alcohols. The overall three-dimensional structures of the enzymes are composed of similar alpha/beta TIM-barrels, and the active site residues Tyr 50, His 113, and Trp 114 interacting with the hydrophilic heads of inhibitors are conserved. We have used molecular modeling and mass spectrometry to characterize the interactions between the enzymes and three aldose reductase inhibitors: tolrestat, sorbinil, and zopolrestat. Unlike the IC(50) values (concentration of inhibitor giving 50% of inhibition in solution), the Vc(50) values measured by mass spectrometry (accelerating voltage of ions needed to dissociate 50% of a noncovalent complex in the gas phase) for the two enzymes are similar, and they correlate with the electrostatic and hydrogen-bonding energies calculated between the conserved Tyr 50, His 113, and Trp 114 and the inhibitors. The results of our comparison agree with detailed structural information obtained by X-ray crystallography, suggesting that nonconserved residues from the C-terminal loop account for differences in IC(50) values for the two enzymes. Additionally, they confirm our previous assumption that the Vc(50) values reflect the enzyme-inhibitor electrostatic and hydrogen-bonding interactions and exclude the hydrophobic interactions.
Aldehyde Reductase↗
FORTRAN source listing for simulating three-dimensional convergent beam patterns with absorption by the Bloch wave method.
The FORTRAN source code is given for a computer program that calculates the two-dimensional intensity distribution in convergent-beam transmission electron microdiffraction (CBED) patterns from perfect crystals. The program uses the eigenvalue or Bloch-wave method. It allows three-dimensional dynamical diffraction, and so includes all higher-order Laue zone effects without approximation. No symmetry reduction is included. The program accepts noncentrosymmetric or centrosymmetric crystal structures and allows absorption corrections to be included. It uses the "EISPACK" subroutines for the diagonalisation of a general complex matrix. Up to 100 CBED disks may be included. The code is also available via "Bitnet."
Electron Probe Microanalysis↗
The segmental effect of Cotrel-Dubousset instrumentation on vertebral rotation, rib hump and the thoracic cage in idiopathic scoliosis.
The segmental effect of Cotrel-Dubousset instrumentation (CDI) on the spine and thoracic cage was investigated in 38 patients with adolescent idiopathic scoliosis by preoperative and postoperative postero-anterior and lateral radiographs and computed tomography from T1 to S1. Mean Cobb angle decreased by 67%. The T5-T12 kyphosis in the hypokyphotic patients increased on average by 8.4 degrees (P < 0.001). Average preoperative as well as postoperative maximal vertebral rotation was located at the apex level, and was reduced from 19.0 degrees to 14.3 degrees (P < 0.001). All vertebrae between the upper and lower instrumented vertebrae were significantly derotated. Average derotation for the apical zone was 4.8 degrees (P < 0.001), for the upper instrumented zone it was 2.5 degrees (P < 0.01), and for the lower instrumented zone it was 2.6 degrees (P < 0.01). Vertebral derotation was significantly higher in the apical zone than in the upper and lower instrumented zones. The apical rib hump index (RHi) decreased by 38% (P < 0.001) and the cumulative RHi for the five apical levels decreased by 34% (P < 0.001). The RHi for the two levels above and below the instrumentation each decreased by 20% (n.s.). No significant increase in sagittal or transverse rib cage diameter at any level was observed. The translation in the coronal plane of the apical vertebra of major right thoracic curves improved significantly (P < 0.001). The preoperative flexibility index of the major curve correlated positively (r = 0.47) with derotation at the apex level (P < 0.01). However, no correlation was found between flexibility index and reduction of RHi at the apex level. Vertebral derotation did not correlate with reduction in RHi at any level. The study shows that CDI results in a postoperative three-dimensional improvement of the spine and a limited improvement of the thoracic cage, with no tendency towards a worsened deformity at any level within or outside the instrumentation.
Adolescent↗
Limit of spared pattern vision following lesions of the immature visual cortex.
Lesions of primary visual cortex sustained early in life spare certain aspects of visual processing that can be linked to expansions of bypass pathways to extrastriate cortex. They also trigger, in an age-dependent way, partial or complete transneuronal retrograde degeneration of beta (X) retinal ganglion cells, which are implicated in visual processing under conditions of low contrast. We used two-dimensional geometric patterns whose saliency was reduced by gradually increasing levels of superimposed masking lines, and by reductions in spatial contrast. Normative data were collected from intact cats, and baseline lesion data were collected from cats with lesions sustained as young adults (postnatal day 180, P180). Experimental data were collected from cats that sustained lesions on P1-3 or P26-30. For high contrast patterns, the adult group was impaired at both acquisition (sequential progressive levels of masking) and concurrent (parallel high and low levels of masking) performance, whereas the early-lesioned groups were impaired only at concurrent performance. All lesion groups were equally impaired when contrast was reduced to modest or lower levels. These results show that sparing of masked-pattern learning is limited to the high end of the spatial contrast domain.
Animals↗
The 3-D monitor and head-mounted display. A quantitative evaluation of advanced laparoscopic viewing technologies.
BACKGROUND: Stereoscopic (3-D) monitors and head-mounted displays have promised to facilitate laparoscopic surgery by increasing positional accuracy and decreasing operative time. To test this hypothesis, we evaluated the performance of subjects using these displays to perform standardized laparoscopic dexterity drills. METHODS: Fifty laparoscopic novices worked within an abdominal cavity simulator using four videoscopic display configurations: (1) standard (2-D) monitor; (2) 3-D monitor; (3) 2-D head-mounted display; and (4) 3-D head-mounted display. Subjects repeated 3 standardized training exercises 2 times. We measured time to complete each drill and number of errors committed. RESULTS: Mean total times to complete all 3 drills were 455, 459, 485, and 449 sec for configurations 1-4, respectively. Mean total errors committed numbered 11.3, 10.4, 12.3, and 10.8, respectively. Neither comparison reached statistical significance (p < 0.05). When 3-D configurations were compared to 2-D configurations overall, a small but statistically significant reduction in errors was noted for 1 drill only (4.3 vs 5.0, p = 0.018). CONCLUSIONS: Three-dimensional imaging slightly reduced the number of errors committed by laparoscopic novices during one test drill; this improvement, however, was not clinically significant. Neither the 3-D monitor nor the head-mounted display decreased task performance time. Widespread adoption of this technology awaits future improvement in display resolution and ease of use.
Clinical Competence↗
Inter- and intramolecular disulfide bonding among lymphocyte plasma membrane proteins and glycoproteins.
The disulfide bonding characteristics of the pig lymph node plasma membrane (PM) proteins and glycoproteins have been examined by 1- and 2-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Reaction of the purified PM vesicles with N-ethyl maleimide (NEM) prior to detergent solubilization was found to markedly reduce the extent of intermolecular disulfide bonding subsequently observed. Thus the blocking of free sulfhydryl groups with NEM prevented the detergent-induced disulfide bonding of numerous components, including PM-bound actin. The extent of intermolecular disulfide bonding among the NEM-pretreated PM glycoproteins purified by lentil lectin affinity chromatography was found to be relatively limited, with only 3% of the total glycoprotein present as intermolecular disulfide-bonded complexes. In contrast, the degree of intramolecular disulfide bonding revealed by a modified 1-dimensional SDS-PAGE technique was quite striking. Among those polypeptides demonstrating a clearly altered mobility upon reduction was the heavy chain of class I and beta-chain of class II major histocompatibility complex (MHC) antigens. The class II alpha-chain, however, was much less affected. These changes have been compared with those observed for proteins containing intramolecular disulfide-bonded domains of known size and number, and considered in the light of recent information on the structure of MHC antigens.
Animals↗
Cytochromes P-450.
1. The cytochromes P-450 are of interest in fields as diverse as biochemistry, pharmacology, mechanistic and synthetic chemistry, carcinogenesis, toxicology, endocrinology, and nutrition. 2. Cytochrome P-450 enzymes are coded by a multi-gene family. 3. The many forms have some elements of similarity in their primary sequences and catalyze chemically equivalent reactions, either mixed-function oxidations or reductions. 4. The catalytic specificity of the individual forms of the enzyme is related to three-dimensional interactions between individual substrates and their binding sites, and the reactions are related in their chemistry. 5. Regulation of enzyme levels appears to involve transcriptional and post-transcriptional aspects.
Animals↗
One-year follow-up of pharmacotherapy-resistant patients with panic disorder treated with cognitive-behavior therapy: Outcome and predictors of remission.
Non-response to pharmacotherapy for panic disorder (PD) is a well-documented problem. However, little information exists to guide next-step strategies for these non-responders. In addition to pharmacologic augmentation strategies, several studies support the efficacy of cognitive-behavior therapy (CBT) for these patients, although data on long-term outcomes has been lacking. In this study, we provide one-year outcomes on a sample of 63 patients who completed group CBT for PD after failing to respond adequately to previous pharmacotherapy. Sustained significant benefit was found for all dimensional outcome scores, and nearly two-thirds of the sample met remission criteria. This occurred with reductions in medication use over the follow-up period. Negative predictors of remission status included comorbid dysthymia, social phobia, and generalized anxiety disorder. These results provide additional evidence for the efficacy of CBT for medication non-responders with PD.
Adult↗
Superior temporal gyrus and the course of early schizophrenia: progressive, static, or reversible?
Accumulating evidence suggests alterations in brain structure, especially in the prefrontal and temporal cortex, in schizophrenia. Previous studies examining the progression of brain structural alterations in schizophrenia have led to conflicting results. Morphometric studies of the superior temporal gyrus (STG) volumes were conducted in a series of neuroleptic-naive first-episode schizophrenic patients, non-schizophrenic first-episode psychotic patients, and matched healthy controls. Three-dimensional MRI scans were carried out in these subjects before and after one year of treatment. Volume reductions were seen at baseline in the left superior temporal gyrus (adjusted for intracranial volume) in both of the patient groups. Pretreatment illness duration was inversely related to the volume of the left superior temporal gyrus; this relation was confined to males. One-year follow-up MRI investigations in a smaller subset of patients suggested that the STG volume reductions may be reversible. No significant changes were noted in the STG volumes in matched healthy controls who were also scanned at baseline as well as at one-year follow-up. These findings have implications for understanding the nature of the neuropathological processes in early schizophrenia, as well as the potential impact of early treatment.
Adult↗
Radiotherapy-induced ear toxicity.
Despite their particular functional consequences, radiotherapy-induced ear injuries remain under-evaluated and under-reported. These reactions may have acute or late character, may affect all structures of the hearing organ, and result in conductive, sensorineural or mixed hearing loss. Up to 40% of patients have acute middle ear side effects during radical irradiation including acoustic structures and about one-third of patients develop late sensorineural hearing loss (SNHL). Total radiotherapy dose and tumour site seem to be among the most important factors associated with the risk of hearing impairment. Thus, reduction in radiation dose to the auditory structures should be attempted whenever possible. New radiotherapy techniques (3-dimensional conformal irradiation, intensity modulated radiotherapy, proton therapy) allow better dose distribution with lower dose to the non-target organs. Treatment of acute and late external otitis is mainly conservative and includes the anti-inflammatory agents (applied topically and systematically). Post-radiation chronic otitis media and the eustachian tube pathology may be managed with tympanic membrane incision with insertion of a tympanostomy tube (grommet), although the benefit of such approach is controversial and some authors advocate a more conservative approach. In these patients the functional deficit can be alleviated by application of bone conduction hearing aids such as, e.g., the bone anchored hearing aid (BAHA). There is no standard therapy for post-irradiation sudden or progressive SNHL yet corticosteroid therapy, rheologic medications, hyperbaric oxygen or carbogen therapy are usually employed (as for idiopathic SNHL), although controversial data on the efficacy of these treatment modalities have been published. In selected cases with bilateral profound hearing loss or total deafness, cochlear implants may prove effective. Further improvements in radiotherapy techniques and progress in otologic diagnostics and therapy may allow better prevention and management of radiation-related acoustic injury.
Audiometry↗
Two-dimensional 1H NMR of three spin-labeled derivatives of bovine pancreatic trypsin inhibitor.
Three nitroxide spin-labeled monoderivatives of bovine pancreatic trypsin inhibitor were prepared with the amino-specific reagent succinimidyl 1-oxy-2,2,5,5-tetramethyl-3-pyrroline-3-carboxylate. The monoderivatives were purified by ion-exchange and affinity chromatography. Thin-layer maps of tryptic peptides of the monoderivatives showed that the spin-label was incorporated at either the alpha-amino group, Lys-15, or Lys-26. Two-dimensional J-correlated 1H NMR spectra of the monoderivatives were recorded. Spectra were also recorded after reduction by ascorbic acid of the nitroxide label to hydroxylamine. With the nitroxide label present, significant line-broadening effects on many of the cross peaks in the spectra were observed. The extent of line broadening for the C alpha H-NH cross peaks was qualitatively correlated with the distance between the labeled amino group and the average C alpha H-NH position in the crystal structure. The spin-label affects cross peaks of protons within approximately 15 A. This study suggests that it is feasible to accumulate sufficient intramolecular distances in order to determine protein solution structures with the aid of distance geometry algorithms.
Amino Acids↗