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At least 343 records · Page 19Linked to original sources
PubMed1988

Reduction of radiation dose and imaging costs in scoliosis radiography. Application of large-screen image intensifier photofluorography.

Photofluorography using a large-field image intensifier (Siemens Optilux 57) was applied to scoliosis radiography and compared with a full-size rare-earth screen/film technique. When scoliosis radiography (PA-projection) was performed on 25 adolescent patients, the photofluorographs were found to be of comparable diagnostic quality with full-size films. A close correspondence between the imaging techniques was found in the Cobb angle measurements as well as in the grading of rotation with the pedicle method. The use of photofluorography results in a radiation dose reduction of about one-half and considerable savings in direct imaging costs and archive space. In our opinion the method is particularly well-suited for follow-up and screening evaluation of scoliosis, but in tall patients the image field size of 40 x 40 cm restricts its usefulness as initial examination.

Adolescent↗
PubMed1983

Functional properties of neurons in middle temporal visual area of the macaque monkey. II. Binocular interactions and sensitivity to binocular disparity.

1. Electrophysiological recordings were made in the middle temporal visual area (MT) of five macaque monkeys. Binocularity and selectivity for disparity were examined using a computer-driven stimulator to activate each eye independently. Results were obtained from 91 single units in MT. 2. Most units in MT receive approximately balanced inputs from the two eyes, and very few could be driven through only one eye. 3. In one type of test for disparity selectivity, units were examined with stimuli that had different but fixed horizontal disparities, thereby simulating frontoparallel movements at different distances from the animal. About two-thirds of ;the units tested for fixed disparity selectivity (52/76) showed pronounced sensitivity to horizontal disparity. Most of these units could be grouped into the same four classes of disparity-tuned units that have previously been described in V1 and V2 of the macaque: near, far, tuned excitatory, and tuned inhibitory. 4. Twenty units were tested for sensitivity to vertical stimulus disparity, which does not normally contribute to stereopsis. Most were as sensitive to vertical disparities as to horizontal. 5. Units were also tested for selectivity for stimuli that moved with changing disparity, simulating trajectories with components of motion toward or away from the animal (motion in depth). No units were found to be truly selective for motion in depth. Units tuned for fixed disparity could appear to prefer motion in depth if tested only with trajectories whose common center point was far from the unit's optimal fixed disparity. However, we do not consider this to represent genuine selectivity for motion in depth, since 1) the responses ara adequately and more easily explained in terms of selectivity for fixed disparity and 2) the best overall response of these units is to frontoparallel motion at the optimal fixed disparity. This observation bears importantly on the interpretation of motion in depth selectivity in previous investigations. 6. The presence of a substantial degree of selectivity for fixed disparity in MT, together with previously demonstrated selectivities for direction and speed, indicates that MT is well suited for the analysis of motion in three-dimensional space.

Animals↗
PubMed2006

Group counseling and psychotherapy across the cultural divide: the case of Ethiopian Jewish immigrants in Israel.

Effective counseling across a cultural divide depends on adaptations or changes of technique to suit the particular intercultural circumstances. The concept of mutual creative space provides a guiding principle for therapists who wish to make such changes. This space is 'negotiated' between the therapist/counselor coming from the 'dominant/mainstream' group within society, and the group participants who arrive from another culture. Mutual creative space consists of the negotiation of power and a process of mutual invention, incorporating the creation, by therapist and participants, of something new that did not exist in either of their cultures of origin. A meaningful encounter and effective group counseling can take place following the negotiation of such a creative space. This is illustrated by the example of intercultural group work with Ethiopian Jewish immigrants in Israel, including an analysis of cultural characteristics of the Ethiopian group and specific ways of negotiating mutual creative space in this case. Issues discussed include: establishing trust in the cross cultural context; the use of body language and its interpretation; the psychologist as an authority figure; active participation vs. hidden learning; and working with dreams in such groups.

Counseling↗
PubMed1998

Build or remodel? Preparing facilities for today's and tomorrow's needs.

As the site for the patient care moves from inpatient settings, hospitals face major decisions about the future of their facilities. Those build in the 1970's and early 1980's do not necessarily accommodate today's technology and patient care equipment, not convert readily to outpatient space. Thus administrators face the challenge of deciding what and how much to remodel in a facility, and what should be new construction. Duke University Medical Center, which includes 1124 licensed inpatient beds, on campus clinics, and off-site primary care practices, has faced such a challenge. In the past five years, administrators, clinicians, and facility designers have systematically reviewed current facility status, and planned renovations and new construction. All inpatient units were renovated in less than two years. During this time, clinical services were maintained and occupancy issues were managed. Space utilization, design and new technology resulted in units better suited to the needs of patients, families and staff.

Academic Medical Centers↗
PubMed2001

New contrast agents for imaging the liver.

The contrast agents suited for hepatic imaging can be divided into nonspecific, extracellular space- (ECS) directed, reticuloendothelial system- (RES) selective, and hepatocyte-selective compounds. There is a wide variation in regard to biodistribution, pharmacokinetics, contrast behavior, and tissue specificity. The ECS contrast agents provide information on vascularization and perfusion similar to that of X-ray contrast agents. The RES- and hepatocyte-specific contrast agents offer more "functional" information that may enhance tissue characterization; however, the biology of the different hepatocellular and nonhepatocellular tumors is limiting the diagnostic efficacy of the tissue-specific compounds in many respects.

Animals↗
PubMedDate not supplied

[Evaluation of +Gz tolerance following simulation of 8-hr flight].

Tolerance of +Gz (head-pelvis) centrifugation of pilots was evaluated following simulation of a long flight on single-seat fighter. The experiment involved 5 test-subjects who were exposed to +Gz before and after simulated 8-hr flight with a growth gradient of 0.1 u/s without anti-g suits and muscles relaxed; in addition, limiting tolerance of intricate profile +Gz loads of 2.0 to 9.0 units with a growth gradient of 1.0 u/s of test-subjects in anti-g suits (AGS) with a change-over pressure valve in the peak mode using muscle straining and breathing maneuvers. To counteract the negative effects of extended flight, various seat configurations: with a back inclination at 30 degrees to the +Gz vector and changeable geometry with a back inclination at 55 degrees to the vector. The other counter-measures applied were cool air shower, suit ventilation, physical exercises, lower body massage with AGS, electrostimulation of the back and lumber region, profiling of the supporting and soft parts of the seat, and 30-s exposure to +5 Gz. Hemodynamic and respiration parameters as well as body temperature were measured in the course of 8 hrs of flight and during and shortly after centrifugation. According to the results of the investigation, seat inclination at 55 degrees to the +Gz vector and tested system of countermeasures prevent degradation of tolerance of large (9 u.) loads following 8-hr flight simulation with the use of the modern anti-g gear,

Acceleration↗
PubMed1991

To excite a heart: a bird's view.

Ultrastructural investigations of avian cardiac muscle, including ratite hearts, have provided great insights into the mechanisms as to how excitation leads to contraction in the heart. The geometry of the conduction fibers of ratite hearts confirms earlier observations on birds showing that the geometry of the conduction system and its component cells is adapted to hearts of different sizes and rates of contraction so as to maintain a differential in conduction velocities between the conduction system and the working fibers. The study of the ratite conduction fibers bears out the idea of an inverse relationship between the size of the gap junctions and the input resistance of cardiac cells. The anomalous extended junctional SR typical of all avian hearts, proscribes the notion of direct contact transduction into calcium release for contraction of an excitatory signal propagating at the cell surface. Couplings appear well suited to maintain direct, if transitory, connections to the extracellular space in addition to harboring channels for intracellular calcium release.

Actin Cytoskeleton↗
PubMed1986

Decompression sickness and intravenous bubble formation using a 7.8 psia simulated pressure-suit environment.

The purpose of this study was to determine the minimum spacesuit pressure required to prevent decompression sickness (DCS) during operational conditions in a 50% oxygen/50% nitrogen environment. In this study, 30 male volunteer subjects were exposed in groups of three, to three consecutive daily extravehicular activity (EVA) simulations at 7.8 psia (5,031 m altitude equivalent) for a continuous period of 6 h. During each altitude exposure, the subjects participated in similar exercise workloads expected to be experienced by astronauts during a typical EVA scenario. Precordial Doppler monitoring revealed that 73.3% of the subjects had intravenous bubbling during at least 1 d of the 3 d of exposure, with 26.7% remaining bubble-free during the entire study. No correlation was found between either body fat or age and incidence of bubble formation. One case of DCS occurred during the study indicating that 7.8 psia is not sufficient pressure to totally preclude DCS in a 50% oxygen/50% nitrogen environment. The necessary pressure awaits further study.

Adult↗
PubMedDate not supplied

Epidural anatomy examined by cryomicrotome section. Influence of age, vertebral level, and disease.

BACKGROUND AND OBJECTIVES: Cryomicrotome section is a means of anatomic examination with minimal artifact ideally suited to delineating details of tissue relationships in the epidural space. In the past, healthy adult lumbar levels have been studied by this method. This report extends observations to other regions of the vertebral column, other age groups, and some abnormal conditions. METHODS: The bodies of 26 adults were frozen in toto soon after death, and the bodies of 2 children were frozen after embalming. Unstained anatomy was revealed by sectioning, and the exposed surface was photographed. RESULTS: As compared with the lumbar level, there are diminished epidural contents at the thoracic and cervical levels, and the ligamentum flavum is more frequently discontinuous. A large basivertebral vein with its origin in the anterior epidural space is typical of the lower thoracic and upper lumbar levels. Although the epidural contents are typically divided into compartments, there is incomplete segmentation of the posterior compartments during early childhood and often at thoracic levels in adults. In advanced age with degenerative disc and joint changes, distortion and compression of the epidural space are typical. CONCLUSIONS: Variations in epidural anatomy due to vertebral level, age, and disease may alter the ease of epidural entry and passage of catheters and injected solution.

Adult↗
PubMedDate not supplied

Countermeasure of the negative effects of weightlessness on physical systems in long-term space flights.

The system of countermeasure of microgravity effects has been developed in Russia that allowed to perform safely long-term space flights. This system that includes different means and methods such as special regimens of physical exercises, axial loading ("Pingiun") and antigravity suits, low body negative pressure device (LBNP, "Chibis") and "cuffs" and others has been used with certain variations at certain stages of flight in 27 successfully accomplished space flights that lasted from 60 to 439 days. The pre-, in- and postflight studies performed in 57 crew members of these flights have shown that the system of countermeasure is effective in preventing or diminishing to a great extent almost all the negative effects of weightlessness in flights of a year and more duration and that the intensity and duration of changes recorded in different body systems after flights do not correlate significantly to flight durations, correlating strongly to the volume and intensity of physical exercises used during flight and especially during concluding stage of it.

Aerospace Medicine↗
PubMed1976

[Distribution of intravenously injected enzymes of heterologous, homologous and autologous origin. Distribution and transport of cell enzymes within the extracellular space. III (author's transl)].

The disappearance rates of intravenously injected enzymes of heterologous, homologous and autologous origin were determined in rats. Within four hours after administration, the activities show an exponential decline, that is either mono- or biphasic. The constant of the exponential function is a measure of the capillary permeability. In the case of biphasic disappearance this holds true only for the first slope, whereas the second one represents the elimination of active enzyme molecules from the extracellular space. If the decline in enzyme activity is monophasic the elimination of those enzymes from the interstitial space is limited by the permeability of the capillary membrane. Enzymes of homologous and autologous origin (extracts of liver or muscle) show a close correlation between their molecular weights and their rates of distribution within the extracellular compartment. For heterologous enzymes (crystallized) such a correlation could not be found. Possible causes for these differences in distribution are discussed. Heterologous and/or crystallized enzymes seem not to be suited for studies on the distribution of cell enzymes within the extracellular space. After enzymes are released from injured cells they undergo the processes of distribution, transport and elimination which are superimposed. The effects of the distribution and transport of enzymes on the results of clinical studies on enzyme elimination are discussed. It seems questionable at this point to assume that from the elimination rate of enzymes and their actual plasma activity one can account for the amount of enzymes originally released from injured cells.

Animals↗
PubMedDate not supplied

Chemography: the art of navigating in chemical space.

Combinatorial chemistry needs focused molecular diversity applied to the druglike chemical space (drugspace). A drugspace map can be obtained by systematically applying the same conventions when examining the chemical space, in a manner similar to the Mercator convention in geography: Rules are equivalent to dimensions (e.g., longitude and latitude), while structures are equivalent to objects (e.g., cities and countries). Selected rules include size, lipophilicity, polarizability, charge, flexibility, rigidity, and hydrogen bond capacity. For these, extreme values were set, e.g., maximum molecular weight 1500, calculated negative logarithm of the octanol/water partition between -10 and 20, and up to 30 nonterminal rotatable bonds. Only S, N, O, P, and halogens were considered as elements besides C and H. Selected objects include a set of "satellite" structures and a set of representative drugs ("core" structures). Satellites, intentionally placed outside drugspace, have extreme values in one or several of the desired properties, while containing druglike chemical fragments. ChemGPS (chemical global positioning system) is a tool that combines these predefined rules and objects to provide a global drugspace map. The ChemGPS drugspace map coordinates are t-scores extracted via principal component analysis (PCA) from 72 descriptors that evaluate the above-mentioned rules on a total set of 423 satellite and core structures. Global ChemGPS scores describe well the latent structures extracted with PCA for a set of 8599 monocarboxylates, a set of 45 heteroaromatic compounds, and for 87 alpha-amino acids. ChemGPS positions novel structures in drugspace via PCA-score prediction, providing a unique mapping device for the druglike chemical space. ChemGPS scores are comparable across a large number of chemicals and do not change as new structures are predicted, making this tool a well-suited reference system for comparing multiple libraries and for keeping track of previously explored regions of the chemical space.

Journal Article↗
PubMed1992

Beyond the basics of endoscopy suite design.

For unit managers facing their first (or next) suite design, these beyond-the-basics points of advice may be helpful: 1. Allow ample time; 2 years from planning to ribbon-cutting is the minimum. 2. Start with the program, not the space. 3. Look ahead 5 to 7 years. 4. Choose an architectural firm with experience in designing endoscopy suites. 5. Work with staff and physicians to assess their needs and benefit from timely feedback on key decisions. 6. Be prepared to be flexible, especially when converting or remodeling space not fully described in existing drawings. 7. Build a client-architect relationship based on mutual respect that will remain in place through the first few months of operation.

Endoscopy↗
PubMed2001

Contrast-enhanced magnetic resonance angiography of the iliac arteries: optimization by injection simulation.

Protocols for contrast-enhanced magnetic resonance angiography (CE-MRA) of the iliac arteries were optimized by computer simulations based on an impulse response function (IRF) of contrast agent (CA) concentration as a function of time obtained for 20 patients. Protocols with sequential, centric, and elliptical k-space coverage, different repetition rates (5 and 10 ms), and CA doses (0.1, 0.2, and 0.3 mmol/kg b.w.) were compared in terms of signal-to-noise ratio (SNR), distortion of vessel profiles, and sensitivity to timing errors. IRF-based simulations successfully characterized CA recirculation. Slow-rate CA infusions were found to achieve relatively high enhancement. In terms of SNR, there is no advantage in increasing the repetition rate. Distortion of vessel profiles is more likely in elliptic and centric k-space coverage. Protocols based on sequential k-space coverage and relatively long CA infusions proved to be particularly suited to large-FOV iliac examinations as they are relatively insensitive to timing errors.

Adult↗
PubMed1989

Crystallization and preliminary X-ray analysis of the human c-H-ras-oncogene product p21 complexed with GTP analogues.

The catalytic domain (amino acid residues 1 to 166) of the human ras-oncogene product p21 complexed with the GTP analogues beta,gamma-imido-GTP (GMPPNP), beta,gamma-methylene-GTP (GMPPCP), and guanosine-5'-(gamma-thiotriphosphate) (GTP gamma S) have been been crystallized. Crystals of the GMPPNP and GMPPCP complexes are well suited for high resolution X-ray crystallography. They belong to space group P3(1)21 (or its enantiomorph P3(2)21) with unit cell axes a=b=40.3 A and c = 162.2 A.

Base Sequence↗