Above 25†nm emission wavelength shift in blue-violet InGaN quantum wells induced by GaN substrate misorientation profiling: towards broad-band superluminescent diodes.

We report a thorough study of InGaN quantum wells spatially modified by varying the local misorientation of the GaN substrate prior to the epitaxial growth of the structure. More than 25 nm shift of emission wavelength was obtained, which is attributed to indium content changes in the quantum wells. Such an active region is promising for broadening of the emission spectrum of (In,Al,Ga)N superluminescent diodes. We observed that the light intensity changes with misorientation, being stable around 0.5° to 2° and decreasing above 2°. This relation can be used as a base for future device designing.

In situ demonstration of the HTLV-I genome in the spinal cord of a patient with HTLV-I-associated myelopathy.

Using polymerase chain reaction (PCR) and in situ hybridization, we investigated the HTLV-I genome in the CNS of an HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patient with a 20-year disease duration. Neuropathologically, there was severe white matter degeneration throughout the spinal cord, but lymphocytic infiltrates were not evident in any lesion. PCR amplification of the pX region of HTLV-I DNA detected its sequence in the spinal cord and all extra-CNS tissue samples. In situ hybridization using probes complementary to the pX and gag regions detected the HTLV-I genome in the cytoplasm and nucleus of cells in the thoracic cord. The findings indicate a direct involvement of HTLV-I in the neurodegeneration of HAM/TSP.

Immunohistological analysis of P53 expression in human skin tumors.

The p53 expression in various skin tumors was immunohistologically evaluated using two mouse monoclonal anti-p53 antibodies, PAb421 and PAb1801. The p53 expression was not detected in the normal epidermal cells. Nuclear staining suggested that the p53 expression was observed in 10 of 26 squamous cell carcinomas (SCCs) from 24 patients, in one undifferentiated carcinoma, one proliferating trichilemmal cyst, one malignant proliferating trichilemmal tumor and in one metastatic carcinoma of breast cancer. None off four cases of Bowen's disease (SCC in situ) showed nuclear staining. In the SCCs, five of 20 primary lesions, three of four recurrent lesions and both of two metastatic lesions had positive nuclei. There was one case of SCC in which a primary lesion was negative but a recurrent lesion was positive. Thus, p53 expression was more frequently observed in SCCs at more clinically advanced stages. This may suggest that p53 has some relevance to progression of SCC. Nuclear staining was not detected in any of the following cases: two cases of seborrheic keratosis, one eccrine poroma, one keratoacanthoma, 11 basal cell epitheliomas, two mammary Paget's disease, three genital Paget's disease, one sebaceous carcinoma, four malignant melanomas, six lymphomas, two leukemia cutis and two angiosarcomas.

Immunohistochemical demonstration of peptidylarginine deiminase in human sweat glands.

Human skin is known to contain protein-bound citrulline. This is the product of enzymatic deimination of arginine residues catalyzed by peptidylarginine deiminase. We probed frozen sections of human skin with a rabbit antiserum raised to rat skeletal muscle peptidylarginine deiminase using the avidin-biotin-peroxidase complex technique. This led us to interesting findings. No staining was observed in epidermis, inner root sheaths of hair follicles, sebaceous glands, and hair erector muscle. However, we noticed specific staining of the cytoplasm of secretory and myoepithelial cells of both eccrine and apocrine sweat glands. The procedure also stained neoplastic cells present in specimens dissected from extramammary Paget's disease. The data mean that peptidylarginine deiminase may be used as a new marker in the classification of skin neoplasms showing sweat gland differentiation. Possible localization of multiple types of peptidylarginine deiminases in human skin is discussed.

Paraganglioma of the cauda equina: an ultrastructural and immunohistochemical study of two cases.

The ultrastructural and immunohistochemical features of 2 paragangliomas arising in the cauda equina are described. In both cases the tumor cells were arranged in small nests or cords and contained characteristic neurosecretory granules, lamellar stacks of rough endoplasmic reticulum (RER), and some well-developed Golgi apparatuses in their cytoplasm. The cells varied in electron density; the darker cells, occasionally resembling sustentacular cells, were probably dehydrated light cells because they contained a few neurosecretory granules. Sustentacular cells were difficult to identify by electron microscopy, but irregularly distributed S-100 protein and glial fibrillary acidic protein (GFAP) were found in these cells by immunostaining. Many tumor cells contained abundant neurofilaments. Curiously, a few cytokeratin-positive cells were found in 1 case. On microscopic examination, a small area of ganglioneuroma was found associated with the paraganglioma in 1 case. Ganglionic differentiation was concluded to be frequent in paragangliomas of the cauda equina region as in duodenal paragangliomas.

Cat scratch disease. An epidemiological and ultrastructural study of lymphadenitis caused by Warthin-Starry positive bacteria.

The aetiological agent of cat scratch disease (CSD) has been unknown for more than 30 years. Recently, a micro-organism clearly shown with Warthin-Starry silver (W-S) stain was found and thought to be a possible cause of the disease. In this study, 32 cases of regional lymphadenopathy histologically compatible with CSD and 20 contrasting cases of lymphadenopathy were examined retrospectively with W-S stain. W-S positive pleomorphic organisms were clearly demonstrated in 20 of the 32 suspected cases of CSD, but in none of the other cases. The onset of disease in these 20 cases with W-S positive organisms occurred between July and January. This seasonal variation in the onset of disease was highly significant (P less than 0.005) and was not due to a single epidemic. Moreover, some characteristic morphological features of the organism were found by electron microscopic observations. Ultrastructurally, the organism was a bacterium showing a chain-like arrangement, septal formation, branching and clubbed ends.

Plasma-cell dyscrasia with polyneuropathy and endocrine disorders associated with dysfunction of salivary glands.

A case of plasma-cell dyscrasia with polyneuropathy and endocrine disorders that showed dysfunction of the salivary glands is reported. A 49-year-old Japanese man noticed swelling of the cervical lymph nodes and numbness in the lower extremities in May 1983. Histological examination of the enlarged cervical lymph nodes revealed many follicles penetrated by radial capillaries and proliferation of capillaries and plasma cells in the interfollicular area, forming Castleman disease-like lesions. The patient complained of a dry mouth and noticed swelling of the submandibular salivary gland in April 1984. Microscopic examination of this gland revealed an angiofollicular lymphoid lesion resembling that in the lymph nodes. He also suffered from an endocrine disturbance characterized by increased serum adrenocorticotropic hormone and impotence. This is the second reported case of plasma-cell dyscrasia with polyneuropathy and endocrine disorders that showed dysfunction of exocrine secretion. This case indicates that attention must be paid to organs of exocrine secretion as well as of endocrine secretion in this disease.