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Biomedical subjects

F Weidner

Publications and source records attributed to F Weidner.

At least 19 recordsLinked to original sources
PubMed2001

Inhibition and enhancement of the spontaneous emission of quantum dots in structured microresonators.

Spontaneous emission of quantum dot systems in laterally structured microcavities that exhibit photon confinement in all three directions has been studied by time-resolved photoluminescence spectroscopy. For on-resonance conditions, we find that the dot emission rate is increased substantially over that of the unstructured planar cavity. For off-resonance conditions, we are able to suppress the emission rate by an order of magnitude by using cavities with metal coatings, which we attribute to the suppression of leaky optical modes in these structures.

Journal Article↗
PubMed1999

Activated T cells enter rat lymph nodes and Peyer's patches via high endothelial venules: survival by tissue-specific proliferation and preferential exit of CD8+ T cell progeny.

Activated T cells reach the lymph nodes via afferent lymphatics but it is unknown to what extent they also enter them directly via high endothelial venules (HEV). Little is known about the mechanism mediating the proliferation of activated T cells within lymphoid tissues in vivo or the subsequent fate of the progeny. Therefore, we stimulated rat T cells via TCR and CD28 in vitro and after injection identified them in the blood and the HEV of lymphoid organs at several time points. In addition, the proliferation of these cells was studied after entering different lymphoid organs. Our results show that, firstly, activated T cells continuously enter lymph nodes and Peyer's patches directly via HEV. Second, they proliferate within lymphoid organs, the rate significantly depending on the microenvironment. Third, mainly CD8+ progeny are able to leave the tissues and re-enter the blood. Thus, the distribution of activated T cells circulating through the body can be regulated during entry, but also within the tissue by influencing their proliferation and subsequent release.

Animals↗
PubMed1999

An acute sign of ischemic infarction: the hyperdense middle cerebral artery.

Ischemic cerebrovascular accidents are a leading cause of death with significant disability common among the survivors. The hyperdense artery sign seen on computed tomography is a useful finding in the early recognition of nonhemorrhagic cerebral infarction. We report a case of a hyperdense middle cerebral artery.

Aged↗
PubMed1996

[Focal epithelial hyperplasia (Heck's disease) in a Turkish family].

A 31-year-old Turkish patient and some family members suffered from multiple hyperplastic oral mucosal papules. Intralesional papilloma virus was not found but the patient had elevated levels of CD8 lymphocytes in his peripheral blood. We diagnosed focal epithelial hyperplasia of Heck.

Adult↗
PubMed1985

Congenital nevi less than or equal to 10 cm as precursors to melanoma. 52 cases, a review, and a new conception.

Fifty-two congenital melanocytic nevi (CMN) as precursors to melanoma or severe melanocytic dysplasia were reviewed macroscopically and microscopically. Forty-eight "small" CMN measured less than 10 cm in diameter. Histologically, only five reached to the lower third of the dermis or subcutis ("deep type"); the remaining 47 were limited to the upper two thirds of the corium ("superficial type"). There were 47 invasive melanomas, two in situ melanomas, and three severe focal melanocytic dysplasias. All melanomas were of "epidermal" origin and primarily of the superficial spreading type. The age at diagnosis ranged from 18 to 79 years. Prepubertal melanomas were not observed. Melanoma may also arise on small CMN. The most frequent origin of the melanomas in small CMN and the preferred age at manifestation seem to be different from that for giant nevi.

Adolescent↗
PubMed1983

Hyperthermic perfusion in malignant melanoma: 5-year results.

Between December 1975 and December 1980 a total of 154 patients with potentially curable malignant melanoma were treated by adjuvant hyperthermic perfusion. The basic therapy consisted in local excision of the primary tumor with elective dissection of the regional lymph nodes. The 4- and 5-year survival rates for our 103 patients with stage-I disease who were perfused are 90% +/- 9% and 80% +/- 17%. The 4- and 5-year survival rates for 51 patients with stage-II disease are 50% +/- 16% and 37% +/- 28%. Compared with historic control groups of patients who were treated at our hospital with the same surgical methods but without perfusion, essentially better results were achieved with adjuvant hyperthermic perfusion. It is concluded from our results that hyperthermic perfusion can further improve the prognosis for patients with malignant melanomas of the limbs.

Chemotherapy, Cancer, Regional Perfusion↗
PubMed1982

The influence of lymph node metastasis and ulceration of primary melanoma on germinal centers within draining lymph nodes: a histomorphometric study.

Microscopic counts and histoelectronic measurement of germinal centers in regional lymph nodes of melanoma patients showed a significant progressive increase in average number, as well as area, of germinal centers with occurrence of (adjacent) metastasis and presence of primary-tumor ulceration. The findings confirm in a quantitative manner the stage-dependent effect of progressive liberation of tumor antigen [10] on lymph node centers of humoral immune response.

Adult↗
PubMed1982

[Papulous mucinosis in lupus erythematosus integumentalis].

Report on a 55-year-old female patient developing skin-colored papules on her back and shoulders after sun exposure and later on typical lupus erythematosus (LE) lesions. During therapy with chloroquine there was regression of LE and annular extension of peripherally developed mucinous papules which did not vanish entirely. Histochemically, dense reticular deposits of metachromatic mucinous material was found in the mid cutis.

Female↗
PubMed1982

[Metastasizing basalioma of the temporal area or continuous extension? Surgical approach and results].

By means of histological sections the rare diagnosis of a basalioma of the temporal area with regional metastases in the parotid gland and in the neck could be verified. Subsequently the surgical treatment and the postoperative results are described. The operation consisted of an en bloc excision of the basalioma, exstirpation of the parotid gland and radical neck dissection. Since the tumor had also infiltrated the facial nerve, the nerve had to be sacrificed and reconstructed using the superficial peroneal nerve. In order to obtain immediately a satisfactory esthetic result in the face region, in addition to the facial nerve graft, the corner of the mouth and the eyelids were taken up using solvent dehydrated dura mater and parts of the temporal muscle and its fascia. A face-lifting supported this procedure. The primary closure of the temporal skin defect was successfully performed using a regional skin flap from the scalp.

Adult↗
PubMed1981

[Classification of malignant melanomas of skin (author's transl)].

Classification of 241 malignant melanomas was made by computer-aided analysis of 14 clinical and 17 histological variables accomplished by clinical diapositives and renewed histological sections. Marked type-related parameters concerned, among others, tumor location, sex and age of patient as well as histological variables of epidermal thickness and surface, intracorneal pigment, sort of melanocytic dysplasia, follicular involvement, dermal elastosis, increased peritumoral vascularity. Tumors demonstrating histologically combined features of SSM and LMM and also spindle celled verrucous melanomas had all to be classified as SSM. Adequate typification of malignant skin melanomas solely by histology provides representative sectioning guided by the histopathologist and then is possible in nearly every case.

Humans↗
PubMed1981

8-year-survival in malignant melanoma related to sex and tumor location.

1,322 melanoma patients in the clinical stage I were followed up for at least 8 years. The females clearly predominated (sex ratio f : m = 2.2 : 1). Trunk melanomas prevailed in males extremity melanoma in females. The overall survival was strikingly better in females than in males. In 936 of the patients exhibiting "high risk" melanomas, tumors located on the upper extremities and on the lower extremities gave the relatively best 8-year-survival rates (60.7% resp. 62.7%). 8-years-survival rates decreased if head (52.8%) and trunk locations (40.3%) were involved. As to these anatomic sites of the primary tumor, there were no statistically relevant differences between the survival rates of the females and the males. Thus, the anatomic site of malignant melanoma is especially important for the prognosis largely explaining the sex differences of the overall survival rates.

Female↗
PubMed1981

[Diagnostic accuracy in epithelial skin tumors].

Between 1967 and 1977 histological diagnosis of 5,238 epithelial skin tumors has been established. 38.6 percent of the material came from dermatologists in practice. The macroscopical diagnosis could be verified in 72.9 percent of the tumors. Highest rates resulted in basalioma, seborrheic keratosis, benign adnexa tumors and precancerous lesions. Clinicians yielded better diagnostic correlation than practitioners. The same was true when the histological diagnosis of epithelial skin tumors was compared with the clinical diagnosis, at a total of 64.5 percent diagnostic correlation.

Diagnosis, Differential↗
PubMed1980

[Malignant melanomas of the skin. Early diagnosis and differential diagnosis.--conclusion].

Amelioration of prognosis in cutaneous malignant melanomas essentially depends on early diagnosis which necessitates the knowledge of some risks and clinical signs of malignancy. The clinical and also histological items of lentigo maligna melanoma, superficial spreading melanoma, acro-lentiginous melanoma and nodular melanoma are referred in detail. Hints are given at the precursor lesions as well as the early signs of malignancy. For differential diagnosis, eight kinds of relatively frequent pigmented skin lesions are discussed.

Angiomatosis↗