Biomedical subjects

A Buchner

Publications and source records attributed to A Buchner.

At least 55 records · Page 3Linked to original sources

PubMed1998

Irrelevant auditory material affects counting.

R. H. Logie and D. A. Baddeley (1987) suggested that event counting may be supported by a phonologically based working-memory structure referred to as the phonological loop. However, inconsistent results concerning the detrimental effects of irrelevant speech on event counting led them to propose that lexical or semantic representations are also involved. In 4 experiments, the authors showed that this extension of Logie and Baddeley's original conceptualization was unnecessary. Instead, the number of irrelevant syllables spoken per time unit, a factor that was not taken into account in previous research, can explain Logie and Baddeley's results. In addition, the present results support the hypothesis that in cases of interference from the auditory channel, correction processes that help to recover the current running total from past running totals are also involved in counting performance.

Adolescent↗

PubMed1998

Radiological features of osteogenic sarcoma of the jaws. A comparative study of different radiographic modalities.

OBJECTIVE: To evaluate the clinical and radiological features of osteogenic sarcoma of the jaws with particular reference to the effectiveness of the radiographic modalities used. MATERIAL AND METHODS: A total of 66 cases (57 from the English-language literature and nine new cases) were critically evaluated for the features depicted with intra-oral and panoramic radiography and CT. RESULTS: The mean age of the patients was 36 years (median 31.5 years). There were no differences in gender distribution. A ratio of 1:1.6 between the maxilla and the mandible was found. Lesions had diffuse borders in 78% of cases and defined but not corticated borders in 22%. Twenty-nine per cent were radiolucent, 29% radiopaque and 41% mixed density. Widening of the periodontal ligament space (PDL) was seen in 14 of the 47 (28%) lesions associated with teeth and structural changes in the mandibular canal in 34% of the mandibular lesions. There was a periosteal reaction in 48% and soft tissue involvement in 33% of the lesions. CONCLUSIONS: Widening of the PDL space was best demonstrated on periapical radiographs. Structural changes in the mandibular canal were shown mainly with panoramic radiographs. Periosteal reaction was best demonstrated by occlusal radiographs and soft tissue involvement by CT. Thorough radiological examination using periapical, occlusal and panoramic radiography, and recognition of the radiological features of osteogenic sarcoma should lead to earlier diagnosis.

Adolescent↗

PubMed1998

An immunohistochemical study of p53 and PCNA in inflammatory papillary hyperplasia of the palate: a dilemma of interpretation.

OBJECTIVE: Inflammatory papillary hyperplasia of the palate (IPHP) or the granular type of denture stomatitis, is a non-neoplastic lesion characterized histologically by a significant epithelial hyperplasia and inflammatory infiltrate usually caused by trauma and Candida infection. p53 and proliferative cell nuclear antigen (PCNA) are cell-cycle regulators, that when overexpressed, are considered by many investigators as markers of malignant transformation. The objective of this study was to investigate the immunodetection of p53 and PCNA in IPHP, and to correlate these results with the degree of epithelial hyperplasia and inflammatory infiltrate. MATERIALS AND METHODS: In 12 cases diagnosed clinically as IPHP, Candida was cultured from the denture base and the palatal mucosa. Lesions were biopsied and stained with H&E for histomorphometric analysis of the epithelial width and inflammatory infiltrate. PAS and Gram stains were used for screening of Candida. Sections were immunostained with DO-7 for p53 and PC-10 for PCNA. Fifteen palatal biopsies obtained from autopsies of edentulous subjects with normal palatal mucosa served as controls. RESULTS: All cultures of swabs from both the palatal mucosa and denture base were positive for Candida. Candidal hyphae could not be identified in PAS stained sections. Small foci of Gram-positive organisms were found in two cases of IPHP. Epithelial width and inflammation were significantly higher in IPHP than in controls (P < 0.001). A three-fold increase in positively stained cells for p53 and a two-fold increase in positively stained cells for PCNA were seen in IPHP compared with controls (P < 0.001). CONCLUSIONS: Although a significant increase in the immunodetection of p53 and PCNA may indicate a malignant potential, IPHP has never been reported to undergo malignant transformation nor is it associated with cytologic signs of dysplasia. The increase in the epithelial width and inflammation degree is probably associated with the colonization of the denture bases with Candida organisms. The increased detection of p53 and PCNA can be a secondary effect of cytokines originating from both the inflammatory cells and the keratinocytes. Thus, immunodetection of p53 and PCNA by current immunohistochemical methods on archival tissues is neither specific nor sensitive enough to be used as indicators for malignant potential in the absence of cytological dysplastic changes or genetic proof of mutated cell cycle genes.

Aged↗

PubMed1997

[Which factors modify the reproducibility of patient positioning in the daily irradiation routine?].

AIM: Factors which influence the accuracy of the field application during daily irradiation routine are not well known. The aim of this prospective analysis was to determine the significance of these factors on the occurrence of field misadjustments in irradiation without immobilization and to evaluate their clinical relevance. PATIENTS AND METHODS: Fifty-three patients received external cobalt-60 beam irradiation without fixation. Once weekly portal images of all treatment fields were carried out. In addition to objective patient data (age, weight, height, general condition, irradiation indication), the psychological situation of the patient during treatment (anxiety, restlessness, pain) and work circumstances of the medical staff during treatment were evaluated once weekly. The distance of clearly visible anatomic structures to the field borders of the portal images were measured and the deviation to the corresponding simulator images was calculated. Patient data were correlated to the number of field misadjustments (deviation larger than 1 cm). RESULTS: Patients whose condition is generally poor and patients being treated palliatively, patients with feeling of anxiety, restlessness or pain during simulation or irradiation and heavy patients (90 kg and more) were more often misadjusted. The number of field misadjustments increased with the stress of the medical staff. CONCLUSIONS: The problem of reproducibility of external beam irradiation without fixation in palliative treatment is of clinical relevance. Effective analgesic therapy and a comfortable and painfree patient set-up reduce misadjustments. In curative treatment, immobilization techniques should be used.

Aged↗

PubMed1997

Clinical and radiological features of odontogenic myxoma of the jaws.

OBJECTIVES: To analyse critically the clinical and radiological features of odontogenic myxoma. METHODS: The clinical features of 164 cases of odontogenic myxoma (two new and 162 from the literature) and the radiological features of 96 cases (two new and 94 from the literature) were analysed. RESULTS: Most of the tumors (75%) were diagnosed in the 2nd to 4th decades. The male to female ratio was 1:1.5. Tumors were located in the mandible in two-thirds and in the maxilla one-third of cases. A multilocular appearance was observed in 55% and unilocular in 36%; 9% were not loculated. There was a statistically significant correlation (P < 0.000) between the size of the lesion and its locularity with the larger lesions more likely to be multilocular. Only 5% of the tumors were associated with an unerupted tooth. CONCLUSIONS: Odontogenic myxoma has a variable clinical and radiological appearance and it should be considered in the differential diagnosis of radiolucent and mixed radiolucent-radiopaque lesions of both jaws in all age groups.

Adolescent↗

PubMed1997

The nature of memory processes underlying recognition judgments in the process dissociation procedure.

The hypothesis is tested that the memory processes involved in recognition judgments in the process dissociation procedure are the same as those involved in standard source-monitoring tasks. It is shown how source-monitoring response categories can be mapped onto process dissociation response categories. On the basis of this abbreviation, an experiment was conducted in which it was possible to compare, using a multinomial modeling approach, the parameters representing memory processes in the process dissociation procedure with those involved in source monitoring. For the two different encoding conditions realized, the results are compatible with the hypothesis that the same processes are involved in source monitoring and in recognition judgments in the process dissociation procedure. Implications for the interpretation of the model's parameters are discussed.

Adolescent↗

PubMed1996

Application of real-time ultrasonography for the detection of tarsal vein thrombosis in cattle.

The clinical and ultrasonographic features of the thrombosis of three tarsal veins in a six-year-old dairy cow are described. Thrombosis and metastatic abscessation developed on the left tarsus six days after the amputation of the lateral claw of the left hindlimb. Originally, the cow suffered from a severe purulent arthritis of the distal interphalangeal joint and a retroarticular abscess, caused by interdigital necrobacillosis. By means of real-time ultrasonography, using a 7.5 MHz transducer, a marked subcutaneous oedema, a subcutaneous abscess, and a thrombosis of the ramus cranialis and ramus caudalis of the vena saphena lateralis reaching the confluence into the vena saphena lateralis and a thrombosis of the ramus caudalis of the vena saphena medialis could be identified. The thrombosed veins were not compressible, were oval and had an increased diameter of up to 9 x 12 mm. Intraluminal masses were visualised as hypoechoic structures and the veins distal to the thrombosis were distended up to 10 x 13 mm. The differential diagnosis and pathogenesis of the thrombosis and the abscessation are discussed, and the clinical course and the sonographic observations of the thrombosis during a six week period are described.

Abscess↗

PubMed1996

On assumptions of, relations between, and evaluations of some process dissociation measurement models.

In this article, we analyze both M. J. Wainwright and E. M. Reingold's (1996) view of the process dissociation measurement models presented by A. Buchner, E. Erdfelder, and B. Vaterrodt-Plünnecke (1995) and their suggestions on that topic. This analysis reveals a number of problems in Wainwright and Reingold's approach. Some of these problems are more subtle than others; but they are nevertheless consequential. Thus, researchers working with the process dissociation procedure should be aware of these problems.

Awareness↗

PubMed1996

Radiologic features of central giant cell granuloma of the jaws.

The radiologic features of central giant cell granuloma (CGCG) have not been clearly defined, and conflicting descriptions appear in the literature. This study analyzes the radiologic and clinical features of 80 cases of CGCG. In nearly 50% of the cases the lesion is located in the posterior area of the jaws, that is, the molar, ramus, and tuberosity, and not in the deciduous teeth-bearing area as was accepted in the past. Only 51% of CGCGs are multilocular, and the frequency of these lesions is significantly higher in the mandible than in the maxilla. The correlation between the lesion's size and its locularity is statistically significant, and larger lesions assume a multilocular appearance. Only 6% of the lesions crossed the midline of the jaws, a feature that was considered in the past as typical for CGCG.

Adolescent↗

PubMed1996

The central odontogenic fibroma and the hyperplastic dental follicle: study with Picrosirius red and polarizing microscopy.

The central odontogenic fibroma (COF) is an uncommon odontogenic tumor in which the microscopic appearance is similar to that of the hyperplastic dental follicle (HDF). Distinction between these lesions is based mainly on their clinical and radiologic features. The collagen of 5 cases of COF and 13 cases of HDF was studied histochemically by staining sections with Picrosirius red and examining them by polarizing microscopy. Polarization colors of the collagen fibers of the lesions were recorded according to their width. While no differences were seen between the polarization colors of thin fibers (<0.8 mm) in both lesions, the polarization colors of thick fibers (1.6-2 mm) of COF were significantly more green and greenish-yellow as compared with those of HDF. These findings suggest that the Picrosirius red polarization method can be used as a diagnostic tool to differentiate between COF and HDF..

Azo Compounds↗

PubMed1996

Pigmented lateral periodontal cyst and other pigmented odontogenic lesions.

OBJECTIVE: To report a case of lateral periodontal cyst (LPC) with marked melanin pigmentation in a 38-year-old Black male and to discuss the phenomenon of melanin pigmentation in odontogenic cysts and tumors. RESULTS: Histologically, the epithelial lining of the LPC contained an abundant amount of melanin granules throughout the entire epithelium. Ultrastructurally, epithelial cells contained mature melanosomes (stage IV melanosomes). Melanophages containing aggregates of melanosomes were identified in the connective tissue cyst wall. Perusal of the literature revealed that melanin pigmentation in odontogenic lesions is uncommon. Melanin has been reported in calcifying odontogenic cyst (18 cases), odontogenic keratocyst (8 cases), adenomatoid odontogenic tumor (3 cases), ameloblastic fibroma (3 cases), odontoma (2 cases), and ameloblastic fibro-odontoma, odonto-ameloblastoma, and odontogenic fibroma (1 case each). CONCLUSIONS: Almost all pigmented odontogenic lesions; occurred in Blacks and Asians; they are almost non-existent in Whites. Thus, racial pigmentation probably plays an important role in such lesions.

Adult↗

PubMed1996

Unconscious Gender Bias in Fame Judgments?

In two experiments the conditions of, and the processes leading to, gender biases in fame judgments were investigated. In Experiment 1, the gender bias was not reduced in a condition that alerted participants to the gender of the names. In Experiment 2, participants' sex-role orientation, but not their gender, was related to the gender bias. The process dissociation procedure was used in both experiments in an attempt to separate conscious and unconscious memory processes contributing to the gender bias. Using L. L. Jacoby's (1991) original measurement model there appeared to be evidence for unconscious influences on the gender bias in fame judgments. Unfortunately, this evidence disappeared when a model was used that takes guessing and, hence, response biases into account, which confirms that measurement models that ignore response biases in the process dissociation procedure may lead to erroneous conclusions.

Journal Article↗

PubMed1996

Investigating Fame Judgments: On the Generality of Hypotheses, Conclusions, and Measurement Models

In this article, we try to clarify some of the issues raised by S. C. Draine, A. G. Greenwald, and M. R. Banaji (1996) concerning our investigation into the gender bias in fame judgments (A. Buchner & W. Wippich, 1996). First, we did not test the general hypothesis and did not draw the general conclusion that Drain et al. suggest we did. Second, we did not reject M. R. Banaji and A. G. Greenwald's (1995) assumptions about the familiarity of male and female names in the fame judgment task, but we showed how one could have come to reject it using a widespread measurement model for the process dissociation procedure. Third, we argue that the processes which Draine et al. suggest should also be included in the measurement model we used are probably negligible, and if they are not, then the validity of the results of a number of fame judgment experiments must be called into question. In general, however, we agree with what seems to be the main message ofM. R. Banaji and A. G. Greenwald's (1995) research, namely, that social categories have to be considered whenever priming is investigated within a social domain.

Journal Article↗

PubMed1996

[Comparative determination of creatine kinase activity in the cerebrospinal fluid and in the blood of health cattle].

Cerebrospinal fluid (CSF) was obtained by puncture of the canalis vertebralis at the lumbosacral foramen. The activities of creatine kinase (CK) in CSF and plasma samples of 68 healthy cattle of different age and breeds were analysed. No significant correlation between CK activities of CSF and plasma was found. The obtained CSF were classified macroscopically into groups of clear-colourless, flaky-colourless, and bloody-flaky samples. The CK activities of clear-colourless CSF showed a normal distribution and were used for further analysis. The range of standard values of CK activities in CSF (0.2-18.7 U/I) was defined after identification of runaways and narrowing of random sample to 95%.

Aging↗

PubMed1995

Metastatic tumours to the oral region. An overview.

Metastatic tumours to the oral region are uncommon. There are more published cases of jawbone metastases than in oral soft tissues. The most common primary sources of metastatic tumours to the oral region are the breast, lung, kidney, bone and colon. The breast is the most common primary site for tumours metastasising to the jawbones, whereas the lung is the most common source for metastases to the oral soft tissues. In the jawbones, the common location of the metastatic lesions is the mandible, with the molar area being the most frequent involved site. In the oral soft tissues, the attached gingiva is the most common affected site followed by the tongue. In nearly 30% of cases, the metastatic lesion in the oral region is the first indication of an undiscovered malignancy at a distant site. The biological basis of the metastatic process is discussed.

Adult↗

PubMed1995

Negative correlations between control performance and verbalizable knowledge: indicators for implicit learning in process control tasks?

Negative correlations between task performance in dynamic control tasks and verbalizable knowledge, as assessed by a post-task questionnaire, have been interpreted as dissociations that indicate two antagonistic modes of learning, one being "explicit", the other "implicit". This paper views the control tasks as finite-state automata and offers an alternative interpretation of these negative correlations. It is argued that "good controllers" observe fewer different state transitions and, consequently, can answer fewer post-task questions about system transitions than can "bad controllers". Two experiments demonstrate the validity of the argument by showing the predicted negative relationship between control performance and the number of explored state transitions, and the predicted positive relationship between the number of explored state transitions and questionnaire scores. However, the experiments also elucidate important boundary conditions for the critical effects. We discuss the implications of these findings, and of other problems arising from the process control paradigm, for conclusions about implicit versus explicit learning processes.

Adolescent↗

PubMed1995

[Clinical chemical investigation of selected laboratory parameters of cerebrospinal fluid and blood of health cattle].

Selected Parameters in cerebrospinal fluid of adult, healthy cattle of different breeds were analyzed. Group size amounted to 68. Liquor samples were taken by lumbosacral punction. At the same time blood was taken from the Vena jugularis for analysis of the same parameters as in cerebrospinal fluid. Classification into 3 groups based on the macroscopic aspect of the cerebrospinal fluid: clear-colourless, flaky-colourless, bloody-flaky. In the first group all parameters were analyzed in order to fix standard distribution. A range of standard values of every parameter in cerebrospinal fluid was defined after finding of runaways and narrowing of random sample to 95%. Standard values for the parameters were: TP 0.83-1.40 g/l, GLU 1.18-3.20 mmol/l, LAC 1.4-1.9 mmol/l, CK 0.2-18.7 U/l, GLDH 0.7-3.7 U/l, AST 3.2-12.8 U/l. Possibilities to integrate results from the other two groups into these standard values were shown. A linear correlation between cerebrospinal fluid and blood serum values was found to exist for GLU (r = 0.91), LAC (r = 0.55) and GLDH (r = 0.48).

Animals↗

PubMed1994

Radiologic features of central odontogenic fibroma.

The central odontogenic fibroma is a rare benign neoplasm that is considered to be derived from mesenchymal dental tissue. This study reviews and analyzes the radiologic features of 51 cases (5 new cases and 46 from the literature). Central odontogenic fibroma appears in both the mandible and maxilla (55% and 45%, respectively). In the maxilla it has a tendency to involve the anterior area, whereas in the mandible the molar and premolar areas are the most prevalent sites. The majority of central odontogenic fibromas are unilocular radiolucent lesions with well-defined borders, but they may also appear as multilocular lesions and in rare instances may exhibit a mixed radiolucent/radiopaque appearance with poorly defined or diffused borders. The great variability in radiologic appearance of the central odontogenic fibroma means that it should be considered in the differential diagnosis of all radiolucencies found in the jaws.

Adolescent↗