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At least 865 records · Page 48Linked to original sources
PubMed2002

Dose calculation along the nonwedged direction for externally wedged beams: improvement of dosimetric accuracy with comparatively moderate effort.

Wedge filters ideally modify photon intensities only in one direction. However, in the other, the "nonwedged" direction, the intensity is affected too; it usually decreases with increasing off-axis distance. For external wedges on a particular treatment machine (Varian Clinac 2100C) and 6 MV photons, for example, this decrease is as big as 8%, depending on wedge angle and material, off-axis distance, and phantom depth. We present a way to account for this effect in prescriptions to points off-center in the nonwedged direction. The goal was to minimize the amount of additional data required for this purpose, without unduly compromising the final prescription accuracy. We measure the effective attenuation coefficients in narrow beam geometry for the wedge materials (lead and steel) as a function of thickness and off-axis angle, and the corresponding attenuation in water, again as a function of wedge material thickness and off-axis angle. The data allow us to extract a correction factor for off-axis distances in the nonwedged direction. Neglecting the contribution of scattered radiation and using primary beam data only, shortens data acquisition and simplifies calculations, but still yields surprisingly accurate results. Application of the derived correction reduces the off-axis distance related dose calculation error in wedged fields to < or =1%.

Biophysical Phenomena↗
PubMed1994

A measurement model for the Type A Self-Rating Inventory.

Compared to other questionnaire measures of Type A behavior, the Type A Self-Rating Inventory (TASRI) possesses particularly strong face validity. This study sought to develop a formal measurement model for the TASRI using a sample of 352 male and 479 female undergraduate psychology students. Assessed via structural equation modeling, an oblique two-factor (Hard-Driving, Extroverted) model explained over 90% of the common variance in responses to a subset of 13 of the original 28 TASRI items for men, women, and the pooled data. As hypothesized, relative to women, men had a greater mean score on the Hard-Driving factor and a lower mean score on the Extroverted factor. However, the magnitude of these gender differences is small. When reconceptualized in the context of work on the Big Five factor model, the Hard-Driving and Extroverted factors were found to reflect related elements of positive sociability and negative power, respectively.

Adolescent↗
PubMed2003

Shared, not unique, components of personality and psychosocial functioning predict depression severity after acute-phase cognitive therapy.

In a sample of 100 patients with recurrent major depression, we collected depression severity data early and late in acute-phase cognitive therapy, plus a wide range of psychosocial variables that have been studied extensively in depression research, including measures of interpersonal, cognitive, and social functioning, and personality traits using an inventory that is linked with the Big-Three tradition in personality assessment theory. By assessing this broad range of variables in a single study, we could examine the extent to which relations of these variables with depression were due to (a) a common factor shared across this diverse set of constructs, (b) factors shared among each type of construct (personality vs. psychosocial measures), or (c) specific aspects of the individual measures. Only the most general factor shared across the personality and psychosocial variables predicted later depression.

Acute Disease↗
PubMed1999

Formation of medical and hospital groups.

The first impression of most physicians and hospitals when dealing with managed care companies (MCOs) is that the size or "bigness" of the MCO is a major factor in the success of the MCO in negotiating contracts. This is only true to a degree. Physicians and hospitals have developed a tendency to make an unqualified bolt to also be "big", to put themselves on a more equal negotiating footing with MCOs. They should consider first the circumstances associated with organizational growth that lead to an effective outcome versus those that lead to failure. Effective outcomes happen because local market share can be controlled; management data systems that work are in place; and senior management has depth as well as maturity.

California↗
PubMedDate not supplied

[Specifics of working with chronic mentally ill patients in Specialised Social Help Services--experiences in training and supervision meetings].

Information was presented on the development and efficiency of The Specialised Psychiatric Social Help Services for the mentally ill in Poland. It took into consideration the specifics of this work and formal requirements for special training of the staff. The experiences of the 3.5 years of work of the specialised services in the Warszawa Targówek district (October 1997 - June 2001) were discussed. Organisational solutions and basic data about clients and staff and establishments and experiences coming from training and supervision meetings were discussed. Problems and difficulties most often experienced by the staff workers at their work with chronic mentally ill patients were described. Consideration was put from one side on the big rotation of the staff and from the other on the need of the extension of the theoretical and practical knowledge as well as of supervision and support was often mentioned in the questionnaire. A need of elaborating the programme of training and professional courses for workers of the specialised psychiatric social help services was also pointed out.

Adult↗
PubMed1989

[Estimation of the parodontium state in seven-year-old children by means of CPITN Index of parodontium medicinal needs].

The purpose of the work was to estimate the parodontium Medicinal Needs of seven-year-old children from the capital city of Warsaw and province by means of CPITN index. Parodontium state in 180 children has been examined: 60 children from Warsaw (a big town), 60 children from Sulejówek (a small town) and 60 children from Wiazowna commune (a village). Each group under examination was composed of 30 girls and 30 boys. A calibrated probe suggested by WHO has been used for the purposes of the examinations. The data obtained during the examinations have been entered in the chart designed by WHO; they estimate 6 sextants in the oral cavity of a child: healthy (H) designated by 0 code, bleeding (B)--by 1 code, existence of dental calculus (C)--by 2 code. In case of the index teeth absence, the sextant has been excluded from the examinations (X). The estimation of parodontium medicinal needs in 7-year-old children has demonstrated that 40.5% of the children have healthy parodontium (H) and doesn't need any treatment; bleeding existed in 59% of the children; dental calculus (C) has been found in 1 child (0.5%). Medicinal needs is restricted to the improvement of the oral cavity hygiene (TN1) in 59% of the children and to the improvement of the oral cavity hygiene and dental calculus removing (TN2) in 1 child. Medicinal needs are identical for the children of both sexes, they differ considerably according to the environment. Action of oral cavity nursing care should include 32% of the children from a large town, 77% of the children from a small town and 70% of the children from a village.

Child↗
PubMedDate not supplied

[The study of V. I. Lenin's brain].

The investigation of V. I. Lenin's brain was carried out on the basis of study of 1108 cytoarchitectonical slices (thickness of 20 mu), stained by Kresil-Violett (Nissl's method) and 558 slices of fibres stained by Geidenhain's method. This is the first in the history of science detailed microscopical study of the man brain, initiated to creation of russian architectonics (as a science of the brain architecture); this study was served for a foundation of structural basis of science on the brain individual variability of different people including prominent persons. The results of this study is compared with a data of the later macroscopic and microscopic investigation of many persons brain with different professions and abilities. The next peculiarities of the Lenin's brain have been written: 1. The relief complexity and peculiarities of sulci and gyri configuration, especially in frontal lobe. 2. The big percentage of the cortex in a deep of the sulci (so called intrasulcal component), and as a result of the increasing of the summarised size of the cortex cerebri. 3. The riches and pronunciation of s.c. limitrophic adaptation's zones between different areas, especially in the frontal lobe and in the other associative cortical structures. 4. The originality in relation in size between area in one region and regarding to the whole cortex surface. The prevail of the size and variability of phylogenetically new (associative) regions, especially of frontal one (which takes part in the function of situation estimation, prognostication, generalization) and also of parietal and temporal cortex; the phylogenetically old zone are more stable. 5. The large number of the especially big pyramidal neurons in sublayer III (III(3)), that can be supposedly looked as a structural basis of the rich associative connections between different cortical regions. The above mentioned peculiarities have been done as a result of the study chiefly of the right brain hemisphere because the left one was seriously suffered as a result of the vessels damage of atherosclerosis origin.

Brain↗
PubMed2005

The mutagenic potential of duodenoesophageal reflux.

SUMMARY BACKGROUND DATA: Duodenogastric-esophageal reflux disease is directly linked to Barrett's esophagus and to the development of esophageal adenocarcinoma. Despite this link, little is known about the mutagenic potential of refluxed material on the esophageal mucosa. We hypothesize that the reflux of gastric and duodenal content causes mutations in esophageal mucosa in vivo. METHODS: Seven Sprague Dawley/Big Blue F1 lacI transgenic rats underwent esophagoduodenostomy (ED) to surgically create duodeno-gastric-esophageal reflux. Fourteen nonoperated rats served as negative (n = 7) and as positive (n = 7/methyl-N-amyl-nitrosamine [MNAN] intraperitoneally) controls. The animals were killed 16 weeks after operation or injection, the entire esophageal mucosa was harvested, and mutation frequency was determined through standard Big Blue Mutagenesis Assay. RESULTS: Gross esophagitis was evident in all operated animals. The frequency of lacI mutations in esophageal mucosal cells of animals with ED was significantly higher, nearly 1.5-fold, than that of nonoperated animals. Nitrosamine administration resulted in a nearly 20-fold increase of lacI mutation frequency. Thirteen mutations were successfully sequenced, 46% occurred at CpG dinucleotide sites and 61% were either C to T or G to A transitions. CONCLUSIONS: The data provide preliminary evidence of the mutagenic potential of bile reflux on esophageal epithelium. The specific mutations are markedly higher than would be expected by chance and are similar to that found in p53 mutations of human esophageal adenocarcinoma, providing a link to human esophageal cancer.

Adenocarcinoma↗
PubMed2004

[A concept of parasite species at the times of molecular studies].

The problem of species recognition in relation to parasite organisms is discussed, based on literature data. Taking into account that over 20 species concepts have hitherto been formulated, the choice of characters, which should define a species differs from author to author. Lately the differences in some gene fragments are regarded as one of most important feature for species differentiation. On this basis some lineages, genotypes or strains have been differentiated within some species, but in most cases the respective authors did not decide to elevate these units to the species level. The present paper focuses on the studies on species representing three genera (Taenia, Echinococcus, Trichinella) as they show, especially the complex studies on the species within the genus Trichinella, how big material is necessary to formulate any proper conclusion and, on the other hand, that the differences in the DNA sequences cannot be the only characters defining species; some other features (morphological, biological, behavioral) should not be considered redundant.

Animals↗
PubMed1996

Lightness contrast in CRT and paper-and-illuminant displays.

The increased use of CRT monitors for displaying and controlling stimuli in studies of surface color poses problems of comparability with data obtained with traditional paper-and-illuminant methods. A review of comparable studies using the two methodologies revealed that CRT studies tend to report larger contrast effects. To investigate factors that may be responsible for this difference, simultaneous lightness contrast was measured using both CRT and paper-and-illuminant presentations. The spatial distribution of luminance in the whole field of view and the visual angles subtended by the displays were controlled. The CRT presentation yielded contrast effects twice as big as those measured for a paper surface in a homogeneously illuminated room. However, a paper display under Gelb lighting yielded almost exactly the same effect size as that measured in the CRT presentation. These results demonstrate that contrast effects in both modes of presentation are affected by the spatial distribution of luminance beyond the basic experimental stimuli.

Adult↗
PubMed2001

[Surveillance of measles in Germany].

In Germany, as in the entire WHO Region Europe, the goal has been set to eliminate measles by the year 2007. In order to achieve this, high vaccination rates of >/= 95 % are necessary as well as an intensive surveillance consisting of a continuous record of the age and region-specific incidence, vaccination rates and the seroprevalence. Data on the vaccination status, recorded in the districts at the time of school entry, are collected centrally and evaluated at the RKI since 1998. The vaccination rate for the 1(st) dose against measles is on the average 84.6 % and for the 2(nd) dose 14.3 %. A nationwide sentinel established in 1999 with over 1200 medical practitioners permits an estimate of the country-wide measles incidence on the basis of the registered measles cases. Results from the year 2000 showed a very big difference between the old Federal States (mean incidence of 46.8 illness per 100 000) and the new Federal States (0.9 per 100 000). Most of those falling sick were unvaccinated (85.4 %), where 35 % refused the vaccination. Thirty-nine percent of the cases were examined in the laboratory and from these 58 % were clinically confirmed; 10 % of the cases occurred in those receiving one dose of vaccine and none in those receiving 2 doses. The age peak of the sick children was between 1 to 4 years of age. Measles notification is obligatory in Germany since January 2001. From these data, the incidence of the 1(st) quarter has been calculated. It varies widely depending on the State (e. g. Bavaria 5.7 / 100.000 vs < 0.5 % in new Federal States). The seroprevalance studies conducted in 1993 and in 1995/96 show large gaps in immunity of small children and suggests that the MMR vaccination may have been carried out too late. The elimination of measles in Germany can only be achieved if the vaccination rates are increased and the 1(st) MMR vaccination is performed as early as possible. In particular, the vaccination rates for the 2(nd) dose are inadequate to be able to reach those with vaccine failures in a greater proportion and to close the gaps of vaccination.

Adolescent↗
PubMed2003

Reasons for elderly patient hospitalization in departments of internal medicine in Lodz.

BACKGROUND AND AIMS: The number of hospitalizations of elderly patients in Poland has been increasing rapidly in recent years. For Lodz, with the oldest population among big cities in Poland, this is an especially important problem. In order to reduce the number of elderly patient hospitalizations, it is first necessary to know the main reasons for these hospitalizations. This study aimed to determine the reasons for elderly patient hospitalizations in Lodz. METHODS: Data related to elderly patients (65 and over) admitted to departments of internal medicine in three district hospitals in Lodz were collected. The reasons for hospital admission, coded according to the International Classification of Diseases-10th Revision, were used for the calculations. RESULTS: Elderly persons accounted for 53.6% of patients hospitalized at the departments studied. The most frequent reasons for hospital admission of the elderly were cardiovascular diseases (CVD) (54.7%) and respiratory tract diseases (19.9%). The most frequent specific diagnoses for hospitalization were coronary heart disease (CHD) (15.7%), pneumonia (11.5%), stroke (8.5%), hypertension (7.2%), heart failure (5.4%), non-insulin-dependent diabetes (5.3%) and insufficiency of cerebral arteries (5.3%). Hypertension was nearly twice as frequent a reason for hospital admission in women as in men. CONCLUSIONS: Elderly persons account for more than half of patients in departments of internal medicine in Lodz. The most frequent reason for hospital admission of the elderly is CVD, particularly CHD.

Age Distribution↗
PubMedDate not supplied

Dioxins, dibenzofurans, dioxin-like PCBs, and DDE in U.S. fast food, 1995.

Food, especially dairy products, meat, and fish, is the primary source of environmental exposure to dioxins in the general population. Little data exists on dioxin levels in the popular and widely consumed "fast foods". Data presented in a previously published pilot study was limited to measuring only the levels of dioxins and dibenzofurans in three types of U.S. fast food. This study adds to the previous paper by presenting data, in addition to dioxins and dibenzofurans, on the closely related dioxin-like polychlorinated biphenyls (PCBs), and the persistent metabolite of DDT, 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (DDE), in four types of popular U.S. fast food. These include McDonald's Big Mac Hamburger, Pizza Hut's Personal Pan Pizza Supreme, Kentucky Fried Chicken (KFC) three piece original recipe mixed dark and white meat luncheon package, and Häagen-Daz chocolate-chocolate chip ice cream. Dioxin plus dibenzofuran dioxin toxic equivalents (TEQ) ranged from 0.03 to 0.28 TEQ pg/g wet or whole weight for the Big Mac, from 0.03 to 0.29 for the Pizza, from 0.01 to 0.31 for the KFC, and from 0.03 to 0.49 TEQ pg/g for the ice cream. Daily TEQ consumption per kilogram body weight (kg/BW), assuming an average 65 kg adult and a 20 kg child, from one serving of each of these fast food ranged between 0.046 and 1.556 pg/kg in adults whereas in children the values were between 0.15 and 5.05 pg/kg. Total measured PCDD/Fs in the Big Mac, Personal Pan Pizza, KFC, and the Häagen-Daz ice cream varied from 0.58 to 9.31 pg/g. Measured DDE levels in the fast foods ranged from 180 to 3170 pg/g. Total mono-ortho PCB levels ranged up to 500 pg/g or 1.28 TEQ pg/g for the KFC and for di-ortho PCBs up to 740 pg/g or 0.014 TEQ pg/g for the pizza sample. Total PCB values in the four samples ranged up to 1170 pg/g or 1.29 TEQ pg/g for the chicken sample.

Adult↗
PubMed1997

Bilateral adrenal neuroblastoma.

Neuroblastoma has been recognized as the most common solid tumor of infancy and childhood. The occurrence of bilateral adrenal neuroblastoma, however, is extremely rare and only a small number of cases have been previously reported. The authors herein report the clinical, histopathological and molecular biological features of two bilateral adrenal cases out of 125 neuroblastoma patients treated at Kyushu University Hospital over a 35-year period. The clinical and histopathological data of the two cases of bilateral adrenal neuroblastoma were reviewed. In Case 1, which had multiple liver metastases, a post-mortem examination revealed bilateral adrenal involvement. In Case 2, which had been detected by mass screening, CT showed masses in both adrenal glands. No big differences in size were recognized between the tumors in either of the cases. A histopathological examination revealed rosette fibrillary type neuroblastomas in both cases. The DNA of these tumor samples stored at -80 degrees C was extracted and the number of copies of the N-myc gene was determined by a Southern blot analysis. Fourteen copies of the gene were detected in Case 1, whereas neither of the tumors in Case 2 showed any amplification. The clinical outcome, histopathological findings and N-myc gene analysis of two cases might support the variety of biological features of this rare group of neuroblastoma.

Adrenal Gland Neoplasms↗
PubMed2003

Increase in nitric oxide bioavailability improves endothelial function in endothelin-1 transgenic mice.

BACKGROUND: Endothelin-1 (ET-1) has been described as a very potent vasoconstrictor. Nevertheless, transgenic mice overexpressing ET-1 have been shown to exhibit normal blood pressure. We thus hypothesized that vascular ET-1 effects may be antagonized by increased activity of other regulatory systems, such as the increase in bioavailability of the endothelial counterpart of ET-1, nitric oxide (NO). METHODS: Endothelium-dependent and -independent vascular function was assessed as relaxation/contraction of isolated preconstricted aortic rings to acetylcholine (10(-10)-10(-4) mol/l), sodium nitroprusside (10(-10)-10(-4) mol/l), ET-1 (10(-10)-10(-7) mol/l) and big ET-1 (10(-10)-10(-7) mol/l), respectively, in ET-1 transgenic mice and corresponding controls. To unmask the impact of the NO system, we furthermore analysed vessel rings incubated in vitro with the NO-synthase inhibitor L-N(G)-nitroarginine methyl ester (L-NAME, 10(-4) mol/l). RESULTS: Maximum endothelium-dependent relaxation was enhanced in ET-1 transgenic mice (93+/-3% vs 84+/-4% for wild-type littermates; P<0.05) and was inhibited by preincubation with L-NAME in both ET-transgenic mice and wild-type littermates (11+/-5% vs 9+/-4% maximum relaxation, respectively). Endothelium-independent relaxation was similar among all groups. Maximum vascular contraction to ET-1 and big ET-1 was reduced in ET-1 transgenic mice (P<0.05 vs wild-type littermates). Preincubation with L-NAME reduced this difference, indicating the involvement of augmented NO availability. Correspondingly, urinary nitrate/nitrite excretion was significantly elevated in ET-1 transgenic mice. CONCLUSIONS: These data suggest that in transgenic mice overexpressing ET-1, increased NO bioavailability counteracts the contractile potency of elevated ET-1 levels and leads to an improvement of endothelium-dependent relaxation. Thus, in the presence of an activated ET system, up-regulation of NO production may be capable of maintaining vascular tone in a normal range and therefore may prevent the development of hypertension.

Acetylcholine↗
PubMed1989

Are there gaps in the provision of perinatal care in Greece?

STUDY OBJECTIVE: The objective was to test the hypothesis that easy access to sophisticated hospitals is associated with a reduction in perinatal mortality. DESIGN: The study was a nationwide questionnaire survey of a birth cohort. SUBJECTS: All deliveries greater than 500g weight of singleton live births and stillbirths occurring throughout Greece during April 1983 were included. Completed questionnaires were returned for 10,953 deliveries (8% of total annual registered births in Greece), and data on 10,790 singleton births were analysed, including 127 stillbirths and 137 early neonatal deaths. MEASUREMENTS AND MAIN RESULTS: The questionnaires contained information on demographic characteristics of each parent, mother's reproductive history, and clinical course of pregnancy, labour and perinatal period. Mothers living in big urban centres were compared with the rest of the country. Overall mortality rates were similar but births in the big urban centres were of significantly lower weight due to fetal growth retardation. Logistic regression analysis, taking account of birthweight, parity, maternal age, and maternal education showed that there was an advantage to mothers living in big urban centres, perinatal mortality being 63% higher in the rest of the country (chi 2 = 7.4, p less than 0.01). CONCLUSION: The evidence obtained supports the original hypothesis and suggest that a reduction in the high perinatal mortality rate in Greece may be achieved by restructuring the perinatal services.

Adult↗
PubMed2004

Lateral inhibition for center-surround reorganization of the frequency map of bat auditory cortex.

Repetitive acoustic stimulation, auditory fear conditioning, and focal electric stimulation of the auditory cortex (AC) each evoke the reorganization of the central auditory system. Our current study of the big brown bat indicates that focal electric stimulation of the AC evokes center-surround reorganization of the frequency map of the AC. In the center, the neuron's best frequencies (BFs), together with their frequency-tuning curves, shift toward the BFs of electrically stimulated cortical neurons (centripetal BF shifts). In the surround, BFs shift away from the stimulated cortical BF (centrifugal BF shifts). Centripetal BF shifts are much larger than centrifugal BF shifts. An antagonist (bicuculline methiodide) of inhibitory synaptic transmitter receptors changes centrifugal BF shifts into centripetal BF shifts, whereas its agonist (muscimol) changes centripetal BF shifts into centrifugal BF shifts. This reorganization of the AC thus depends on a balance between facilitation and inhibition evoked by focal cortical electric stimulation. Unlike neurons in the AC of the big brown bat, neurons in the Doppler-shifted constant-frequency (DSCF) area of the AC of the mustached bat are highly specialized for fine-frequency analysis and show almost exclusively centrifugal BF shifts for focal electric stimulation of the DSCF area. Our current data indicate that in the highly specialized area, lateral inhibition is strong compared with the less-specialized area and that the specialized and nonspecialized areas both share the same inhibitory mechanism for centrifugal BF shifts.

Acoustic Stimulation↗
PubMed1976

[The azygos system].

The great variety of anatomical dispositions of the azygos system explains its facility of adaptation. The second lumbar vein is able to play a buffer role between the caval systems or, conversely, is able to direct venous flow to a preferential system. In case of portal hypertension, an inferior omphalo-azygos flow by the right ascending lumbar vein was noticed. Finally, the left venous system may either be the major element of the azygos system (mainly by a big ascending lumbar vein) or be divided in 2 distinct streams to the azygos venous trunc. The final disposition of the azygos system seems to correlate well with a progressive evolution towards an unique trunc, linking directly the two caval systems (this being confirmed by foetal data). Practically, the study of the arterial and venous relations of the azygos crossing have interesting applications in surgery.

Azygos Vein↗