Biomedical subjects
Publications and source records attributed to D Heller.
Ewing's sarcoma is an uncommon malignancy that usually occurs in childhood and is rare in the mandible. A case of Ewing's sarcoma of the mandible is presented and discussed.
1. The importance of MHC genes and background genes in controlling disease resistance, including resistance to avian coccidiosis, has not been clarified in meat-type chickens. 2. The role of class IV MHC genes in resistance to Eimeria acervulina was assessed in F2 progeny of a cross between 2 meat-type lines, selected divergently for immune response to Escherichia coli. 3. Disease susceptibility was assessed by lesion score, body weight, packed cell volume and carotene absorption. 4. Chickens with the "K" class IV MHC haplotype had lower lesion scores than chickens with "F" and "A" haplotypes. 5. Plasma carotene concentrations were higher in chickens with "K" haplotype and lower in chickens with "F" and "A" haplotypes whereas body weight and packed cell volume were less sensitive measures of Eimeria infection. 6. Eimeria acervulina resistance appears to be associated with MHC class IV genes; information about MHC haplotypes may be useful in selecting for increased resistance of meat-type chickens to coccidiosis.
Three experiments investigated visual search for singleton feature targets. The critical dimension on which the target differed from the nontargets was either known in advance or unknown--that is, the critical difference varied either within a dimension or across dimensions. Previous work (Treisman, 1988) had shown that, while the search reaction time (RT) functions were flat in both conditions, there was an intercept cost for the cross-dimension condition. Experiment 1 examined whether this cost would disappear when responses could be based on the detection of any (target-nontarget) difference in the display (by requiring a "heterogeneity/homogeneity" decision). The cost remained. This argues that pop-out requires (or involves) knowledge of the particular dimension in which an odd-one-out target differs from the nontargets; furthermore, that knowledge is acquired through the elimination of dimensions not containing a target. In Experiment 2, the subjects had to eliminate (or ignore) one potential source of difference in order to give a positive response (displays could contain a "noncritical" difference requiring a negative response). The result was a comparatively large cost in the within-dimension (positive) condition. This can be taken to indicate that pop-out as such does not make available information as to the particular feature value in which the target differs from the nontargets. Experiment 3 examined whether search priorities can be biased in accordance with advance knowledge of the likely source of difference. The subjects were found to have a high degree of top-down control over what particular dimension to assign priority of checking to. The implication of the results for models of visual search and selection are discussed.
This case study demonstrates that team development takes time. It involves interpersonal skill development for staff members, management training, and specific team building sessions after the teams form. It is crucial that the specific content of training for managers, staff members, team leaders, and team members evolves from an assessment of organizational needs coupled with involvement of all levels of the department. You may ask if this entire process has made a difference. Yes, it has. Staff members are beginning to be more open and honest with one another regarding issues detrimental to the group process. Above all, team leaders and staff are assuming responsibility together for the workload and process improvement. Implementing the team process without proper training and assessment is sure to fail. Yet we must continue to work and shape the team process toward the final level of self-direction.
"This paper investigates why Third World cities have been growing in the last several decades much more quickly than cities in industrialized countries. For this purpose, we develop a Krugman-type model of economic geography with two continents, North and South, each of which consisting of two regions, East and West. We study the impact different levels of transport costs and tariffs exert on the distribution of economic activities among the regions. We find that lower costs for transport between the regions in the South, for instance, induced by an improved infrastructure, as well as lower tariffs on intercontinental trade tend to lead to less concentrated economies." (SUMMARY IN GER AND FRE)
The recognizability of a letter is impaired by the presence of additional letters. This phenomenon is called lateral masking. Proceeding on the assumption of Bouma (1970) lateral masking can be described in terms of retinal eccentricity of the target letter and the distance between target and flanking stimuli. In this paper, we will address to the question if these kinds of parameters are adequate for describing lateral masking effects. For this purpose, characteristics of the string like its length and its homogenity are varied. The subject's task is to identify the central letter of a tachistoscopically presented string. The targets in the string are flanked both by only x and by different randomly selected letters. Additionally, we varied the length of the string. The data show that these variations influence the strength of the masking effect. It is concluded that a pure sensorical approach is not sufficient for an explanation of lateral masking effects.
A transvaginal sonographic (TVS) scoring system using morphologic features has been developed at our institution to maximize discrimination between benign and malignant ovarian and adnexal cysts. Low (4-7) or intermediate (8-9) scores have been found to correlate with benignity, hence TVS-guided or laparoscopically directed needle aspiration of low-scoring lesions may safely be performed. High-scoring lesions (10-14) are often malignant, therefore in situ needle aspiration of such lesions is not recommended. The aim of our study was to correlate the results of TVS characterization of ovarian and adnexal cysts with the aspiration cytologic evaluation. Twenty-three of the 43 cysts studied were aspirated in situ from the patient; 20 were aspirated from resected surgical specimens. Thirty-six benign cysts had TVS scores ranging from 4 to 12, with a median score of 7. All 25 cysts that were benign by TVS and/or histology were also cytologically benign as well as an additional 11 cysts that were not resected (TVS scores: 4 to 9). Seven cytologically and histologically malignant cysts had high TVS scores (TVS scores 10-14; median = 12). The combination of TVS and needle aspiration cytology is valuable, particularly in the diagnosis of cysts having low or intermediate TVS scores and benign cytology. Aspiration of cysts or masses with high TVS scores is not recommended. This combined evaluation may allow a more limited surgical approach, such as operative laparoscopy, or, in some cases, obviate the need for operative treatment altogether.
OBJECTIVE: Our purpose was to immunolocalize urokinase-type plasminogen activator and the plasminogen activator inhibitors 1 and 2 in human implantation sites, with emphasis on the types of trophoblast expressing the plasminogen activator and the inhibitors. STUDY DESIGN: Urokinase and the plasminogen activator inhibitors 1 and 2 were localized immunohistochemically in early human implantation sites in unruptured ectopic pregnancies from patients in an in vitro fertilization program. RESULTS: Urokinase kinase and the plasminogen activator inhibitors 1 and 2 were localized in the cytoplasm of cytotrophoblasts and in the cytoplasm and plasma membranes of intermediate and syncytiotrophoblast. Greater staining was noted in nonvillous, relative to villous, cytotrophoblasts for urokinase and both inhibitors. CONCLUSIONS: Urokinase-type plasminogen activator and the plasminogen activator inhibitors 1 and 2 were localized in all three forms of trophoblast at the maternal-fetal interface in early human implantation sites, particularly the differentiated and invasive forms of trophoblast. These results support a role for the plasminogen activator or inhibitors in the controlled invasion of the maternal decidua by the trophoblast during human implantation.
It has been proposed that epithelial ovarian cancers arise in germinal inclusion cysts of the ovary, which are thought to form as stigmata of ovulation. To evaluate whether the frequency of germinal inclusion cysts is associated with ovarian cancer, the authors counted the germinal inclusion cysts in single slides of sections from ovaries of 148 women who underwent incidental oophorectomy and from the contralateral ovaries of 37 women with unilateral ovarian cancer at Columbia-Presbyterian Medical Center, New York, New York, in 1985-1991. The mean number of germinal inclusion cysts was 2.7 for cases and 3.6 for controls. Conditional logistic regression analysis showed that germinal inclusion cysts were not associated with ovarian cancer (odds ratio = 0.98, 95% confidence interval 0.92-1.04). These findings do not support the hypothesis that increased formation of inclusion cysts is a risk factor for ovarian cancer.
Information on MHC may improve the efficiency of selection for immunological traits via the application of marker assisted selection or by selecting directly for a specific restriction fragment length polymorphism (RFLP) band or MHC haplotype. An experimental procedure is presented here for identifying MHC genes that are related to early immune response. A Class IV cDNA clone was used to probe Southern blots of erythrocyte genomic DNA from chickens. Chickens were taken from the second (S2) and third (S3) generations of replicated lines divergently selected for high antibody response (HC1, HC2) or low antibody response (LC1, LC2) to Escherichia coli vaccination at 10 days of age. These selection criteria have been found to be associated with other immunological parameters. The hypothesis that these selected lines differ in their MHC loci was evaluated by comparing the frequencies of MHC RFLP markers (single RFLP bands) and haplotypes (patterns of RFLP bands). The significant differences between LC and HC in the frequency of many MHC RFLP bands and of five MHC haplotypes indicate that early antibody production is influenced by MHC genes. The reliability of the association between the selection and frequency differences was tested and proven in most cases by analysis of the replicated lines. These differences in RFLP markers represent a change in allelic frequencies in MHC genes, probably due to selection. The results imply a connection between the Class IV genes and early antibody production, and they show the potential of prospective breeding not only by immunological phenotype but also by genotype (i.e., using RFLP markers of the MHC).
In several experiments the motion after-effect as elicited by spirals and gratings ("waterfall displays") is used to analyze the processing of information within the visual system. The duration and judged strength of after-effects are determined with respect to different fixation conditions (monocular and binocular fixation conditions as well as centric and eccentric fixation). The results show, that motion after-effects in spirals and waterfall displays are generated and processed in different ways within the visual system. The results are discussed on the basis of a metric of the visual system by means of the motion after-effect.
The purpose of this study was to examine histologically and radiographically the effect of a bleaching agent, a mixture of sodium perborate and superoxol (30% hydrogen peroxide), without a heat source on the cervical root surface and periodontal tissue of endodontically treated teeth of dogs. Endodontic treatment was performed on anterior teeth of dogs. The endodontically treated teeth were then divided into two groups. One group received walking bleach procedures, while the other group did not. The animals were killed at intervals of 1 and 3 months after bleaching for histological and radiographic examination. External cervical root resorption was only observed in bleached teeth at 3-month but not at 1-month observation.
Fourteen cases of Papillary Endometrial Carcinoma (EC) were analyzed by Interactive Computerized Morphometry. Seven cases were diagnosed as well differentiated adenocarcinomas with papillary features (PF) and belonged to a group of EC with associated adenomatous hyperplasia (AH). Seven cases were diagnosed as uterine papillary serous carcinomas (PA) and belonged to a group of EC without associated AH. Two morphometric procedures were used. DRAW for the characterization of individual nuclei (area, perimeter, chord) and NU-MEAS for tissue architectural features (crowding and stratification). Using a stepwise discriminant multifactorial analysis, both methods proved to be accurate for the two diagnostic categories, as shown by the 100% posterior probabilities and by the two diagnostic categories, as shown by the 100% posterior probabilities and by the distances between group means. A doubtful case was analyzed and classified using a K-nearest neighbor procedure, compared to the individual case in the database. The distinction between the two types of papillary EC is important for the differential diagnosis of the two lesions. Well differentiated adenocarcinoma with papillary features is seen usually in the context of a well-differentiated adenocarcinoma, in a group of patients known to have estrogen-related less aggressive tumors. Uterine papillary serous carcinoma was described to have a biological behavior similar to that of papillary ovarian carcinoma and is encountered in a group of patients with more invasive and less differentiated EC2. Computerized interactive morphometry is a valuable method to use for the accuracy of this differential diagnosis in doubtful cases.
Epidermal growth factor (EGF) and its receptor (EGF-R) were immunohistochemically localized in trophoblast during human implantation from intrauterine and ectopic pregnancies. EGF immunostaining was absent to light in the cytotrophoblast (CT), light to moderate in intermediate trophoblast (IT), and intense in the syncytiotrophoblast (ST). In ST, EGF immunostaining was found mostly in the cytoplasm; however, staining of the plasma membrane was also noted. Immunostaining for the EGF-R was absent to light in the CT and moderate to intense in the IT. Immunostaining for the EGF-R was intense in the ST, with moderate staining in the cytoplasm and intense staining in the plasma membrane. Staining was most intense on the microvilli of the ST. Additionally, EGF-R immunostaining could be demonstrated on nuclear membranes. The increase in the intensity of the immunostaining for both EGF and EGF-R noted in CT, IT, and ST suggests a differentiated expression of this receptor-ligand system in human trophoblast and provides evidence for an autocrine/paracrine role for EGF in trophoblast function. The presence of this receptor-ligand system during early human implantation strongly supports a role for EGF and the EGF-R in embryo-uterine signalling and the implantation process.
It has repeatedly been shown that the time and accuracy of recognizing a word depend strongly on where in the word the eye is fixating. Word-recognition performance is maximal when the eye fixates a region near the word's center, and decreases to both sides of this "optimal viewing position." The reason for this phenomenon is assumed to be the strong drop-off of visual acuity: the visibility of letters decreases with increasing eccentricity from fixation location. Consequently, fewer letters can be identified when the beginning or ending of a word is fixated than when its center is fixated. The present study is a test of this visual acuity hypothesis. If the phenomenon is caused by letter visibility, then it should be sensitive to variations of visual conditions in which the letters are presented. By increasing the interletter distances of the word (e.g., a_t_t_e_m_p_t), letter visibility was decreased. As expected from our hypothesis, the viewing-position effect became more exaggerated. An additional experiment showed that destroying word-shape information (e.g., aTtEmPt) decreased overall word-recognition performance but had no influence on the viewing-position effect. Varying the viewing position in words might thus be used as a paradigm, allowing one to separate out the contribution of letter information and supraletter information to word recognition.
To test the utility of biotinylated DNA probes against various subtypes of human papillomavirus (HPV), we performed in situ DNA hybridization on routinely processed archival material from 30 patients with serial cervical biopsies including conization (group I) and a prospective group of 35 patients whose cervical biopsies showed various degrees of koilocytotic atypia and/or dysplasia (group II). Commercially available biotinylated probe cocktails against HPV types 6 and 11, 16 and 18, and 31, 35 and 51 were detected via the avidin-biotin horseradish peroxidase technique. Virus was found in 87% (26/30) of group I and 57% (20/35) of group II. Almost exclusively, viral types 16, 18, 31, 35 and 51 were detected in group I; 54% (19/35) of group II stained for types 16, 18 or 31, 35 and 51; 2.9% (1/35) stained for types 6 and 11. Nine percent of group II (3/35) showed coinfection with types 16, 18 and 31, 35 and 51. Three of six vulvar condylomata (50%) stained for types 6 and 11. In general, weaker staining was associated with greater dysplasia. In situ hybridization using biotinylated DNA probes is useful in identifying patients infected with dysplasia/carcinoma-associated HPV subtypes and can be performed easily on routine surgical specimens.
Twenty women with cervical and vaginal human papillomavirus-associated lesions were treated with CO2 laser ablation followed by eight weekly applications of 5-fluorouracil. Viral subtyping in a majority of patients and histology were obtained before and after treatment. After treatment 88% (15 of 17) had normal vaginal biopsies, and 59% (10 of 17) had normal cervical biopsies. There were no treatment failures with subtype 6/11 infection of the cervix or vagina. All the failures were with viral subtypes 16/18 and 31/35/51. The protocol was effective in treating patients with cervical and vaginal human papillomavirus-associated lesions.
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