Shinichi Morino

Three‐dimensional structural changes in cerebral microvessels after transient focal cerebral ischemia in rats: Scanning electron microscopic study of corrosion casts

Pathological changes of cerebral microvessels in transient ischemia were investigated by scanning electron microscopy of vascular corrosion casts. Wistar rats were treated with middle cerebral artery (MCA) occlusion for 30 min, 1 h,  3 h,  4 h,  5 h  or  7 h  and  subsequent  reperfusion  for 2 h. The ultrastructures of the cast were observed and computer‐aided montage micrographs were obtained for visualization of the whole microvasculature in the ischemic brain hemisphere. Avascular areas representing ischemic areas were detected in the frontotemporal cortex and caudate putamen in the groups from 30 min to 5 h occlusion. Extravasation of the resin, which probably corresponded to the leakage of plasma or hemorrhage, was seen as spheroidal, conglomerative, large massive and worm‐like types. The spheroidal type, which probably indicated a small leakage or minor hemorrhage, began to appear in the 30‐min occlusion group. The conglomerative type, which probably indicated a larger leakage or moderate hemorrhage, appeared in the 3‐ to 5‐h occlusion groups. The large massive and worm‐like types, which probably indicated a significant hemorrhage, appeared in the 4‐ and 5‐h occlusion groups. The number of these extravasations increased significantly in the 4‐h occlusion group. Arterioles near the avascular area frequently showed vasospastic appearances, such as corrugations, fusiform indentations of endothelial nuclei, continuous circulatory constrictions and severe narrowing with interrupted branches. Arteriolar vasospasm possibly caused prolonged hypoperfusion even if reperfusion was achieved. The capillaries had a thin stringy appearance in the 4‐ and 5‐h occlusion groups. These changes seemed to relate closely with increased intracranial pressure by brain edema or hemorrhage. The present study suggested that the risk of brain edema or hemorrhagic infarction increased beyond 3 h of MCA occlusion, and vasospasm of the arterioles might participate in stroke pathophysiology.

A case of cutaneous protothecosis successfully treated with local thermal therapy as an adjunct to itraconazole therapy in an immunocompromised host

We report a case of human protothecosis in an immunocompromised host which was caused by Prototheca wickerhamii and was successfully treated with thermal adjunct therapy combined with systemic itraconazole therapy. A 78-year-old man taking 30 mg prednisolone daily had a 1-week history of erythematous plaques on the dorsal aspect of his right hand and forearm after sustaining a small traumatic injury. Histopathology of the lesions revealed granulomatous inflammatory changes with numerous microorganisms that had multiple septations in their cytoplasm. On the basis of mycological features and the results of the sugar assimilation test, the etiologic agent was identified as Prototheca wickerhamii. Although the lesion showed no response to the systemic itraconazole therapy and topical ketoconazole treatment, a complete resolution was achieved by the use of thermal therapy as an adjunct to systemic itraconazole.

Myofibroblastic differentiation in atypical fibroxanthomas occurring on sun-exposed skin and in a burn scar: an ultrastructural and immunohistochemical study

Herein, we report the investigation of two cases of atypical fibroxanthoma (AFX). One AFX developed within actinically damaged skin, as is typical, while the other developed within a burn scar within non‐sun‐exposed skin. The two tumors showed almost identical histopathological, immunohistochemical and ultrastructural features. The tumors were composed of pleomorphic spindled, epithelioid, multinucleated and bizarre cells with enlarged atypical nuclei. Most tumor cells expressed vimentin and about 50% expressed CD10. Some tumor cells also expressed α‐smooth muscle actin and CD68. However, there was no expression of cytokeratins, p63, S‐100 protein, melan‐A, HMB 45, desmin, epithelial membrane antigen or CD34. Ultrastructurally, the tumor cells contained myofilaments with dense patches but lacked plasmalemmal caveolae and basal lamina. The most prominent finding was the identification of fibronexus junctions. In addition, there were tumor cells containing numerous lysosomal granules. In conclusion, we clearly showed myofibroblastic differentiation in AFX by electron microscopy. We report also a case of AFX directly developing within a burn scar in the absence of actinic damage.

Syringocystadenoma papilliferum on the male nipple

Syringocystadenoma papilliferum is a rare benign adnexal tumor that most frequently arises from an organoid nevus on the head and neck. Occurrence of this tumor on the male breast is extremely rare. A 74‐year‐old Japanese man presented with a nodule on his left nipple. Histopathological findings were typical for syringocystadenoma papilliferum. Ultrastructurally, constituent epithelial cells of the tumor were divided into three types. We focused on one cell type, undifferentiated clear cells, which have been suggested to be pluripotent cells bearing stem cell nature in syringocystadenoma papilliferum. Immunohistochemically, the tumor cells were negative for cytokeratin 15, which is known as a relatively specific marker for multipotent stem cells in the follicular bulge. We speculated that the clear cells are slightly differentiated toward apocrine rather than stem cells. We also ruled out the possibility of a relationship between the clear cells and Toker cells, which have a clear cytoplasm and are present in the areola region. Dermoscopic examination revealed amorphous milky white areas that corresponded to the pathological findings of luminal deposition of the tumor.

Novel morphological study of solar lentigines by immunohistochemical and electron microscopic evaluation

Solar lentigines (SL) are hyperpigmented lesions generally seen in elderly people. Their pathogenesis has not been completely elucidated. We examined 75 cases of SL using routine histopathology and immunohistochemistry. In addition, seven cases were evaluated by electron microscopy. Histopathologically, we observed vacuolar changes in the dermoepidermal junction in 85% of the cases. Dermal melanophages were seen in 77% of the cases. The immunohistochemical expression rates in the epidermis for cytokeratin (CK)15, CK14, CK10, p63 and nestin were 76%, 100%, 100%, 100% and 17%, respectively. In 58 cases showing dermal melanophages, expression rates of CD163 and factor XIIIa on melanophages were 79% and 83%, respectively. Double positivity for both proteins was identified in 44 cases (75%). Ultrastructurally, vacuolar structures were seen in the cytoplasm of basal cells and upper dermis in all cases examined. We observed elimination processes of damaged basal keratinocytes, which were probably produced by ultraviolet (UV) irradiation, into the papillary dermis. The segregated damaged cell bodies containing melanin granules seemed to be phagocytosed by poorly immunostimulatory macrophages labeled immunohistochemically by CD163 and factor X IIIa, contributing to prolonged pigmentation of SL. In addition, repeated basal keratinocyte damages may be in association with altered CK and p63 expression patterns in the constituent cells of SL.

Three-dimensional Structure of a Parameatal Urethral Cyst by Scanning Electron Microscopy

We report scanning electron microscopy (SEM) for a case of parameatal urethral cyst. A 6-year-old Japanese boy presented with a cyst on the right lateral side of the urethral meatus. Histological examination revealed a cyst lined with columnar epithelium. An immunohistochemical study showed positive staining for CK7, CK13, and CEA, and negative for CK20 in luminal cells. On SEM examination, the inner surface of the cyst showed ridges arranged in a gyrus-like manner at lower magnification. Higher magnification revealed luminal cells with short microvillus projections. Some cells showed apocrine, merocrine, and possibly holocrine-type secretions.

Mitochondrial changes in motor neurons of homozygotes of leucine 126 TT deletion SOD1 transgenic mice

We investigated the time course of ultrastructural changes of mitochondria in the spinal cord of homozygotes of Leu126TTdel SOD1 (superoxide dismutase 1) with FLAG (signal sequence at the C‐terminal protein) transgenic mice (DF‐homo). Non‐Tg mice and wild‐type human SOD1 with FLAG epitope transgenic mice (WF) were investigated as controls for non‐onset Tg mice. Expansion and vacuolation of the mitochondrial matrix was exhibited in motor neurons in the anterior horns of DF‐homo Tg mice at the presymptomatic stage. Such mitochondrial degeneration became severe at the postsymptomatic stage. In contrast, expansion of the mitochondrial inner‐membrane space was not evident even at the terminal stage. Microvacuoles of cytoplasm and fibrillar inclusions were rarely shown from the early symptomatic stage. WF mice showed expansion and vacuolation of the mitochondrial inner membrane space at old age. Non‐Tgs showed no obvious change in mitochondria. Gold‐labeled human SOD1 immunoreactivity showed small amount of gold deposits in the vacuolated mitochondria. These results suggest that the expansion and vacuolation of mitochondrial matrix in the spinal cord of DF‐homo transgenic mice is the first pathological change, but that it is not directly caused by the aggregation of an abnormal human SOD1 protein in intermembrane space of mitochondria.

Novel in vivo observations on double acting points of luliconazole on Trichophyton rubrum: an ultrastructural study

Scales from lesional skin of 12 patients with tinea pedis were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to gain an insight into the spatial and morphological changes of dermatophytes after application of a clinical dosage of topical luliconazole 1% cream (Lulicon® cream 1%). In all cases, Trichophyton rubrum was identified. The scales from the lesions collected before and after topical luliconazole application were fixed with glutaraldehyde and subjected to SEM and TEM. For SEM, fixed specimens were first placed in 1N-KOH and then post-fixed and observed. SEM showed a swollen appearance of fungal hyphae as an early change, and then shrinkage of them showing a flattened and twisted appearance as a later change. TEM showed cell wall alterations with initial development of and accumulation of a granular structure in the outermost layer and subsequent amorphous and electron-lucent change of the thickened inner part of the cell wall. This is the first report of dramatic morphological changes of T. rubrum before and after topical luliconazole application in vivo demonstrated by SEM and TEM. We hypothesize that luliconazole has double acting points, on the plasma membrane and cell wall, of dermatophyte hyphae.

Scanning Electron-Microscopic View of the Oral and Basal Epithelial Surfaces of the Rat Soft Palate

We studied corresponding structures on the oral and basal surfaces of the oral epithelial layer, focusing on the microanatomy of gustatory papillae. Specimens for scanning electron microscopy were obtained from the rat soft palates and fixed with a mixture of 2% paraformaldehyde and 1% glutaraldehyde. They were first prepared without postfixation and conductive-staining to study the oral surface. After examination, the epithelium was reinforced by additional sputter coating and treated with 6 N NaOH at 60°C to exfoliate the basal epithelial surfaces without any significant artifacts. The papillae, showing circular, elliptical or fusiform protuberances on the oral surface, were classified into two types: types I and II. The type I and type II papillae contained one and two taste pores, respectively. On the basal epithelial surface, the basal portions of the taste buds were associated with concentrically arranged nerve fibers and Schwann cells. Another characteristic finding on the basal epithelial surface was the presence of excretory ducts of minor salivary glands in a close spatial relationship to taste buds. It is suggested that saliva coming out through the duct is mixed with food, thus enabling intimate contact with the taste pores of the papillae.