PubMed Health⌕ Search

Biomedical subjects

D Melcher

Publications and source records attributed to D Melcher.

17 recordsLinked to original sources
PubMed2004

[The use of methylphenidate in children: analysis of prescription usage based in routine data of the statutory health insurance bodies concerning drug prescriptions].

UNLABELLED: In Germany only few data is available on the use of stimulants in the treatment of Attention Deficit/Hyperactivity Disorder. For the first time a full survey of health insurance data was carried out on methylphenidate prescriptions from 2000 to 2001 in an East German District. 783 patients of the total cohort received at least one prescription for methylphenidate. In our sample, the treatment prevalence more than doubled in the observation period from 0.6 % to 1.4 % in children aged between 5 and 15 years, this age group representing the largest treatment group. Younger children, adolescents and adults were only rarely treated. The treatment was undertaken predominantly by paediatricians, general practitioners and neurologists/psychiatrists/child psychiatrists. Prescriptions were issued by one, or by not more than two doctors. CONCLUSION: In Mecklenburg-Vorpommern the prevalence of stimulant treatment has clearly increased. Since diagnosis-related data is not available it is not possible to assess the indications for treatment. Further studies should serve to evaluate the correspondence between diagnosis and therapy in relation to stimulant medication.

Adolescent↗
PubMed2001

Visual scene memory and the guidance of saccadic eye movements.

An unresolved question is how much information can be remembered from visual scenes when they are inspected by saccadic eye movements. Subjects used saccadic eye movements to scan a computer-generated scene, and afterwards, recalled as many objects as they could. Scene memory was quite good: it improved with display duration, it persisted over time long after the display was removed, and it continued to accumulate with additional viewings of the same display (Melcher, D. (2001) The persistance of memory for scenes. Nature 412, 401). The occurrence of saccadic eye movements was important to ensure good recall performance, even though subjects often recalled non-fixated objects. Inter-saccadic intervals increased with display duration, showing an influence of duration on global scanning strategy. The choice of saccadic target was predicted by a Random Selection with Distance Weighting (RSDW) model, in which the target for each saccade is selected at random from all available objects, weighted according to distance from fixation, regardless of which objects had previously been fixated. The results show that the visual memory that was reflected in the recall reports was not utilized for the immediate decision about where to look in the scene. Visual memory can be excellent, but it is not always reflected in oculomotor measures, perhaps because the cost of rapid on-line memory retrieval is too great.

Attention↗
PubMed1999

Shapes, surfaces and saccades.

Saccadic localization of spatially extended objects requires the computation of a single saccadic landing position. What representation of the target guides saccades? Saccades were examined for various targets composed of dots to determine whether landing position corresponded to the center-of-gravity (average location) of the dots, the center-of-area of the shape, or the symmetric axis. Targets were composed of dots configured as outline drawings of circles, ellipses, cardioids, wiggly lines, or amorphous blobs. In some cases, dot spacing was varied, extraneous dot clusters were superimposed, or different distributions of dots inside the boundary were added. Quasi-random dot clusters without a well-defined contour were also studied. Instructions were to look at the target as a whole, and keep latency long enough to avoid compromising accuracy. Saccades landed with a high level of precision (S.D.s 7-10% of target eccentricity) near the center-of-area of the target shape, rather than at the center-of-gravity of the dots or on the symmetric axis. Landing position was unaffected by the spacing of dots along the boundary, the addition of dots within the boundary, or the addition of the extraneous dot clusters. When the target was a cluster of quasi-random dots, saccades landed closer to the center-of-area of the implied surface than to the average location of the dots. Overall, the positions of individual dots were important only insofar as the dots affected overall target shape. The results show that a representation of target shape guides saccades, rather than a more primitive representation of individual elements within the attended region.

Female↗
PubMed1996

Differential expression of gp200-MR6 molecule in benign hyperplasia and down-regulation in invasive carcinoma of the breast.

In this study, we used immunohistochemical and biochemical analysis to show that gp200-MR6, a 200 kDa molecule that is functionally associated with the human interleukin 4 (IL-4) receptor complex, is expressed at high levels on normal breast epithelial tissues, at lower levels on in situ carcinomas, and that the expression is lost in the invasive carcinoma of the breast. Furthermore, a preliminary study showed that benign epithelial hyperplasia of the breast expresses the gp200-MR6 heterogeneously. Two populations of cells have been observed: MR6 positive and MR6 negative. Interestingly, MR6-positive cells were observed to have different morphology from those that were MR6 negative; the nuclei of the former were larger and rounded in shape, whereas the nuclei of the latter were relatively small and oval in shape. In sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting, monoclonal antibody MR6 detects the same molecular weight molecule in both normal and transformed tissue, indicating that the molecule is not a product of a truncated gene. The intensity of the gp200-MR6 bands correlates with the immunohistochemical data, indicating that the molecule is expressed at high levels in normal tissue and at lower levels in malignant tissue. These results suggest that analysis of gp200-MR6 expression may be useful in tumour grading and prognostic evaluation in breast cancer. Moreover, the molecule may be involved early in the process of tumorigenesis of the breast, in which a loss or a down-regulation of gp200-MR6 could contribute towards tumour development and progression via an effect on cell growth and differentiation.

Antigens, CD↗
PubMed1996

Rapid review.

Explore the source record for details and available documents.

Female↗
PubMed1995

Role of re-screening of cervical smears in internal quality control.

AIMS: To investigate the use of rapid re-screening as a quality control method for previously screened cervical slides; to compare this method with 10% random re-screening and clinically indicated double screening. METHODS: Between June 1990 and December 1994, 117,890 negative smears were subjected to rapid re-screening. RESULTS: This study shows that rapid re-screening detects far greater numbers of false negative cases when compared with both 10% random re-screening and clinically indicated double screening, with no additional demand on human resources. The technique also identifies variation in the performance of screening personnel as an additional benefit. CONCLUSION: Rapid re-screening is an effective method of quality control. Although less sensitive, rapid re-screening should replace 10% random re-screening and selected re-screening as greater numbers of false negative results are detected while consuming less resources.

Cytological Techniques↗
PubMed1994

Identification of glioma-associated antigen MUC 2-63 as CD44.

Monoclonal antibody MUC 2-63 recognises neurogenic tumours and has been used successfully for radioimaging human malignant gliomas. We now show that the MUC 2-63 antigen has the same tissue distribution and molecular weight range as the CD44 antigen and confirm the identity of these two molecules in blocking studies using MUC 2-63 and the CD44 anti-framework antibody F10-44-2. Thus not only MUC 2-63 but also other anti-CD44 monoclonal antibodies should prove useful in imaging and, perhaps, therapy of brain tumours.

Antibodies↗
PubMed1990

Tumour-associated upregulation of the IL-4 receptor complex.

In a previous study we have shown that monoclonal antibody MR6, which we believe recognizes a component of the human IL-4 receptor complex, binds to a wide variety of epithelial tumours. We have now used this reagent to carry out more detailed analysis of tumours of the breast. Our immunohistochemical data indicate that approximately 30% of these tumours show elevated expression of the molecule to which MR6 binds. In addition, three samples of lymphoma were all MR6-positive. Normal breast tissue from the same patients was either negative or weakly positive. Immunoprecipitation and Western blotting analysis with MR6 show that the molecule expressed on tumour cells is indistinguishable from that on normal tissues. It has an apparent molecular weight of 200 kD, but is highly sensitive to proteolysis yielding a molecule of 145 kD. These data raise the possibility that upregulation of the IL-4 receptor complex may be involved in tumourigenesis. In addition, since only a third of tumours are MR6-positive, the antibody may have potential in differential diagnosis.

Antibodies, Monoclonal↗
PubMed1988

Association between villous atrophy in rheumatoid arthritis and a rheumatoid factor and gliadin-specific IgG.

93 patients with rheumatoid arthritis (RA) were examined for histological or other evidence of gut abnormalities. 44 had raised levels of IgG to gliadin, and of these 38 (86%) were also positive for IgA rheumatoid factor (RF). 24 patients (15 with raised levels of IgA RF and wheat protein IgG [AB+] and 9 with normal levels of both antibodies [AB-]) underwent jejunal biopsy. 6 of the AB+ and 1 of the AB- patients had villous atrophy. The AB+ group had lower villous surface/volume ratio and small intestinal lactase concentrations than did the AB- group or age-matched controls. There was no significant difference between the two groups of RA patients in disease severity or treatment regimen. The findings suggest that the gut may play a more important part in the immunopathogenesis of some cases of RA than in others, and that the former may be identified by raised levels of IgA RF and wheat protein IgG.

Adolescent↗
PubMed1987

The lower limb as a presenting site of malignant lymphoma.

Cutaneous malignant lymphomas should be considered in the differential diagnosis of unusual swellings or ulcers presenting on the limbs. Four cases on the lower limb are described. They may appear as nodules, plaques or ulcers and it is recommended that cytology is used to supplement histology in diagnosis. Successful treatment with radiotherapy is possible but the overall prognosis is frequently poor.

Aged↗
PubMed1978

Malignant lymphomas. A cytological/histological classification.

Early diagnosis and differentiation of malignant lymphomas is important as the various types have a very different prognosis. Aspiration cytology is useful in the initial diagnosis, monitoring the change from one cell type to a more primitive cell type and for diagnosing spread of lymphoma.

Classification↗
PubMed1976

Transplantation in mesangiocapillary glomerulonephritis with intramembranous dense "deposits": recurrence of disease.

Six patients with mesangiocapillary glomerulonephritis and intramembranous dense "deposits" developed terminal renal failure and were transplanted, three from living and three from cadaver donors. Eight renal biopsy specimens were obtained from five of the grafts, from 1 to 26 months following transplantation. All six biopsy specimens taken later than seven months following the graft showed recurrence of dense intramembranous "deposits" in the basement membranes of glomeruli, and of Bowman's capsule and tubular basement in five. Recurrence of "deposits" was associated with deposition of C3 on immunofluorescent study in all but one specimen; in addition, IgM was found in two specimens, but IgG and early complement components were absent. Only two patients, however, showed glomerular proliferation associated with profuse proteinuria. In the other subjects the recurrence of the "deposit" was not associated with clinical findings. Graft loss, which occurred in two patients, was predominantly from rejection.

Adult↗
PubMed1975

Assessment of diagnostic aspiration curettage as an outpatient procedure.

Aspiration curettage proved acceptable to patients and medical staff when incorporated into a busy outpatient practice. The diagnostic reliability of curettings obtained was shown to be 93.5 per cent accurate. In all patients where mucus only is obtained, where symptoms persist or recur, or when aspiration curettage is too distressing, conventional curettage is mandatory.

Cytodiagnosis↗