Light microscopy. Extracellular sheath and lipid droplets of dermal melanocytes in semithin Epon sections.
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Cytoplasm↗
Biomedical subjects
R Knobler
Publications and source records attributed to R Knobler.
[Oculodermal melanocytosis (nevus of ota) and blue nevus (author's transl)].
Report is made of a patient having concurrently an Ota nevus and a blue nevus. The dermal melanocytes showed a marked formation of large intracytoplasmatic vacuoles. Reference to the important role of an "extracellular sheath" is made. The nearly identical ultrastructural characteristics of dermal melanocytes in various dermal melanocyte disorders seems to imply a common pathological origin in their development.
Adult↗
[Nervus of ota (author's transl)].
A 27-year-old woman presented with a distinct gray-blue coloration of the left eye and the periorbital region. The right periorbital region also displayed minimal pigmentation. It was established that eye drops containing mercury had been administered for some years. Initially hydargyrosis was considered as an etiologic factor. Finally we arrived at the diagnosis of nevus of Ota on conjunction with a blue nevus on the forehead. The simultaneous occurrence of a nevus of Ota and the blue nevus suggest a common basic developmental disturbance. The nevus of Ota represents a benign dermal hyperpigmentation syndrome and has to be differentiated from melanosis bulbi.
Adult↗
Challenge of penicillin-allergic volunteers with penicillin-contaminated meat.
In order to obtain information about the clinical course and immunological background of possible allergic reactions due to penicillin-containing food, nine volunteers with penicillin allergy proved by case history, positive skin tests and/or positive penicilloyl-specific RAST were exposed to penicillin-contaminated pork. For this purpose a farm pig from an inbred strain received "therapeutic" doses of benzyl procain penicillin before being slaughtered. Meat samples were taken from muscle tissues, kidney and liver and analyzed by diffusion and extraction methods. Very small amounts of penicillin were detectable in muscle tissue, whereas kidney material contained up to five times as much (0.12 mcg/g). Except two cases which reacted with itchy sensations after ingestion of penicillin contaminated meat "á la tartare", all probands were clinically free of symptoms. Assaying penicilloyl-specific IgE antibodies by RAST during the trial, a tendency to increased levels in the serum after 2 and 24 h was noted, whereas the titers of BPO-specific IgG antibodies measured by the red cell-linked antigen-antiglobulin reaction (RCLAAR) remained unchanged. It is concluded from this study that small and hidden amounts of penicillin and its derivatives in food seldom induce anaphylactic reactions in penicillin allergic patients.
Adult↗
In vivo validation of tissue segmentation based on a 3D feature map using both a hamster brain tumor model and stereotactically guided biopsy of brain tumors in man.
The purpose of this study was to validate our MR tissue segmentation technique using a hamster brain tumor model and malignant brain tumors in man. We used a multispectral tissue segmentation analysis. Three sets of MRI data were included: proton density, T2-weighted fast spin echo, and T1-weighted spin echo, as inputs. Three image preprocessing steps included correcting image nonuniformity, application of an anisotropic diffusion type filter, and data point selection by a qualified observer. We used the k-Nearest Neighbor segmentation algorithm, which does not require prior knowledge of the sample distribution. This choice allowed us to optimize the different tissue clusters present in three-dimensional (3D) feature space. In vivo validation of the technique was performed in hamsters harboring tumors induced with JC virus-transformed HJC-15 cells, as compared to three control animals. Human brain tumors obtained by stereotactically guided biopsy in six patients were also included in the study. Finally, brain tumors were removed from two patients who underwent conventional craniotomy using segmentation-derived images as a guide. In the hamsters, 10 tissues were correctly identified by segmentation and were confirmed histologically (P < .02). In the patients, there was also a strong correlation between our segmentation results and the tissue obtained by stereotactic biopsy (P < .01). In one of the two patients who underwent open craniotomy, segmentation images were useful in revealing tumor spread into vital areas of the brain (motor area). In conclusion, the results of segmentation correlate well with the tissues in vivo and thus warrant further clinical utilization and evaluation.
Adult↗
T-cell clones specific for myelin basic protein induce chronic relapsing paralysis and demyelination.
Experimental allergic encephalomyelitis (EAE) serves as a model for autoimmune diseases mediated by T lymphocytes. Following sensitization to rat, mouse or guinea pig myelin basic protein (MBP) in complete Freund's adjuvant, inbred mouse strains PL/J (H-2u), SJL/J (H-2s) and (PL/J X SJL/J)F1((PLSJ)F1) develop EAE. Whereas sensitization to the N-terminal 37 amino-acid peptide of rat or guinea pig MBP [MBP(1-37)] induces EAE in PL/J mice, immunization to the C-terminal peptide (89-169) leads to EAE in SJL/J mice. The immune response to MBP in (PLSJ)F1 mice is not co-dominant; sensitization to the N-terminal peptide induces EAE, while sensitization to the C-terminal peptide does not. We have generated MBP-specific T-cell clones restricted to class II (Ia) antigens of the major histocompatibility complex (MHC) from PL/J and (PLSJ)F1 mice following sensitization to rat MBP. Two such I-Au-restricted T-cell clones that proliferate in response to the encephalitogenic N-terminal MBP peptide and recognize a shared determinant with mouse (self) MBP cause paralysis in 100% of (PLSJ)F1 mice tested. Paralysis is induced even when recipients are injected with as few as 1 X 10(5) cloned T cells. Relapsing paralysis followed in two-thirds of the recipients after recovery from acute paralysis, whereas one-third developed chronic persistent paralysis, a form of EAE not usually seen. Histopathology revealed intense perivascular inflammation, demyelination and remyelination within the central nervous system of paralysed mice. The experimental disease induced with these clones shares important features with human demyelinating diseases such as multiple sclerosis. This is the first demonstration that T-cell clones that respond to a defined self-antigen can induce clinical and histological autoimmune disease.
Animals↗
Marked and sustained improvement of systemic sclerosis following polychemotherapy for coexistent multiple myeloma.
We present the case of a patient who had systemic sclerosis (SSc) with progressive cutaneous and pulmonary involvement and a coexisting monoclonal gammopathy which gradually progressed to overt multiple myeloma. Strikingly, successful VMCP (vincristine, melphalan, cyclophosphamide and prednisolone) polychemotherapy for myeloma was accompanied by a marked and sustained improvement of SSc that has persisted for 2 years after chemotherapy. Most noticeable was a substantial skin softening in our patient, with a > 50% reduction in the skin thickness score following VMCP treatment. Our case suggests that polychemotherapy may represent a promising treatment option in patients with SSc who are refractory to available treatments.
Aged↗