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Biomedical subjects

M Morohashi

Publications and source records attributed to M Morohashi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Ultrastructural characteristics of trichilemmal cysts: report of two cases.

Two trichilemmal cysts (TC) on the scalps of two Japanese women were examined at the electron microscopic level. The ultrastructural characteristics of the TC included an abrupt transition from nucleate to anucleate cells, a few oval, small, keratohyaline granules mixed with increasing numbers of tonofibrils from the peripheral layer towards the center, spherical particles with lipid droplets, desmosomal structures in keratinized cells, and the interdigitation of keratin in the uppermost keratinizing cells. The keratinization pattern of the TC was unique in that typical soft or hard keratinization processes did not occur. Trichilemmal keratinization is observed in the trichilemmal sacs that surround the lower ends of catagen or telogen hairs, as well as in the outer root sheaths in the follicular isthmus of anagen hairs. Comparison of the ultrastructure of these two known types of trichilemmal keratinization with the keratinization pattern of the TC in our patients indicates that TC may differentiate into, or originate from, the proliferation of the outer root sheath in the follicular isthmus of anagen hairs.

Adult↗
PubMed2001

Ultrastructural characterization of microvasculature in photoaging.

The cutaneous microvasculature was examined by electron microscopy in order to compare its characteristics in photodamaged preauricular skin and in sun-protected postauricular sites of 15 Japanese women aged 58-81 years. The characteristic ultrastructural features of the microvasculature in photodamaged skin compared with those in sun-protected skin included dilated vessels embedded in elastin which depressed endothelial cells, vessels surrounded by a thick amorphous material composed of multiple laminations of a basement membrane-like material, and activated endothelial cells which had increased numbers of cytoplasmic organelles and pinocytotic vesicles. A novel finding of this study in photodamaged vessels was an increased formation of new vessels (angiogenesis) via two distinct pathways. In severe elastosis, activated endothelial cells with densely packed intracytoplasmic microfilaments extended large pseudopods into the elastotic material. In contrast, isolated mesenchymal cells, which possessed immature Weibel-Palade bodies, were scattered around pre-existing vessels within the Grenz zone. In some cases, many mesenchymal cells with electron-lucent cytoplasms aggregated and interconnected by cytoplasmic processes, which was followed by the formation of vascular structures. These results suggest that there are significant ultrastructural differences in vessels between photoaged and intrinsically aged facial skin and that the photodamaged microvascular system is characterized by the co-existence of regressive changes and angiogenesis.

Aged↗
PubMed2001

Immunohistochemical expression of cyclooxygenase-2 in skin cancers.

BACKGROUND: Cyclooxygenase (COX), also known as prostaglandin endoperoxide synthase, catalyses the conversion of arachidonic acid to prostanoids. There are two different isoforms of COX, referred to as COX-1 and COX-2. Overexpression of COX-2 has been demonstrated in various neoplasms, such as experimentally promoted tumors, gastrointestinal cancers and breast tumors. METHODS: In this study, we used immunohistochemistry to investigate COX-2 expression in a series of basal cell epitheliomas (BCE), Bowen's disease, squamous cell carcinomas (SCC) and metastatic tumors of the skin. RESULTS: Four of 16 BCE showed a positive reaction for COX-2 and the adenoid type of BCE was the most strongly positive. In Bowen's disease, the extent of positive staining for COX-2 was even higher than that in BCE. Eleven of 15 SCC showed a positive reaction for COX-2 and the pattern of staining was heterogeneous with more intense staining in the center of the tumor nests. In metastatic tumors, the percentage of COX-2-positive tumor cells and the intensity of their staining was low compared with Bowen's disease and SCC. CONCLUSIONS: These results indicate that the intensity of COX-2 staining and its heterogeneous distribution are related to the degree of cellular differentiation and the various phenotypes of tumor cells, but the extent of COX-2 staining did not correlate with the degree of malignancy.

Adenocarcinoma↗
PubMed2001

Immunohistochemical study of inducible nitric oxide synthase in skin cancers.

BACKGROUND: Nitric oxide (NO) is synthesized from the amino acid L-arginine by NO synthase (NOS). Experimental evidence suggests that increased express of inducible NOS (iNOS), which is an NOS isoform and calcium independent, is related to various pathological processes, such as inflammation and cancer. METHODS: In this study, we used immunohistochemistry to investigate iNOS expression in a series of basal cell carcinomas (BCC), Bowen's disease, squamous cell carcinomas (SCC), extramammary Paget's disease (EPD) and metastatic tumors of the skin. RESULTS: Only 1 of 16 BCC cases was positive for iNOS and the intensity of staining was weak. In most of the 10 cases of Bowen's disease, iNOS was weakly expressed and there was a wide range in the percentage of positive tumor cells. Twelve of the 16 cases of SCC were positive for iNOS and the extent of positivity was greater than in Bowen's disease. Two of the 7 cases of EPD were positive for iNOS, and 12 of the 15 cases of metastatic cancer were positive. Well-differentiated adenocarcinomas were diffusely positive, whereas poorly-differentiated ones showed strong and heterogeneous staining. CONCLUSIONS: These results indicated that the expression of iNOS may reflect the proliferation of tumor cells and that a heterogeneous distribution of iNOS may correlate with a wide variety of biological behavior of tumor cells.

Adenocarcinoma↗
PubMed2001

Expression of neuropeptide-degrading enzymes in alopecia areata: an immunohistochemical study.

BACKGROUND: Much clinical evidence suggests that the nervous system, including psychological factors, can influence the course of alopecia areata (AA). However, there has been little substantial evidence of specific participation of cutaneous neurogenic factors in the disease process. OBJECTIVES: As previous studies have demonstrated that stress elicits the release of the neuropeptide substance P (SP) from peripheral nerves and that some patients with AA show prominent SP expression in nerves surrounding their hair follicles, we aimed to evaluate the role of SP in AA. METHODS: We used immunohistochemistry to examine the expression of SP and SP-degrading enzymes in scalp biopsies from patients with AA and from healthy controls. RESULTS: Affected hair follicles in the centre of the areas of hair loss of patients with AA were richly innervated by SP-staining nerve fibres. Strong expression of the SP-degrading enzyme, neutral endopeptidase (NEP), was observed in hair follicles not only in the acute progressive phase of AA but also in the chronic stable phase. Expression of NEP in hair follicles from the margins of areas of hair loss was stronger than in normal controls, but was weaker than in the centre of the areas of hair loss. In addition, endothelial immunoreactivity for angiotensin-converting enzyme (also capable of degrading SP) was not observed in the centre of the areas of hair loss, which was in significant contrast to normal controls as well as to the margins of areas of hair loss where it was expressed. Further, intense expression of endothelial leucocyte adhesion molecule-1 on vessels and many degranulating mast cells was observed adjacent to affected hair follicles in AA, in admixture with dense lymphocytic inflammation. CONCLUSIONS: These findings suggest that SP is endogenously released by dermal nerve fibres around hair follicles and that it may play an important part in epithelial-mesenchymal-neuroectodermal interactions in AA. This study reveals that SP and its degrading enzymes are involved in the pathogenesis of AA, which in turn might explain the pathological significance of neurogenic and psychogenic aspects in the disease process.

Adult↗
PubMed2001

L-lactic acid as a mosquito (Diptera: Culicidae) repellent on human and mouse skin.

The attraction of Aedes albopictus (Skuse) to hands and forearms of human subjects treated with several concentrations of L-LA solution were studied in a test chamber containing proboscis-amputated mosquitoes. Fewer mosquitoes alighted on L-LA treated human skin than on water-treated control skin. Similar results were found using normal mosquitoes following L-LA and water treatment of mouse skin. The relative repellent effects of L-LA varied with concentration. The minimum repellent concentration was lower than previously reported for human skin. The number of alightments decreased at increasing concentrations of L-LA, demonstrating the absolute repellency of L-LA. Unlike previous reports suggesting that L-LA attracted mosquitoes, our studies using human and mouse skin showed that L-LA exhibited both relative and absolute repellency.

Aedes↗
PubMed2001

Characteristics of Pseudomonas aeruginosa isolated from skin infections.

From January 1995 to June 2000, 19 Pseudomonas aeruginosa were detected in 19 cases of infectious skin diseases. Coagulase-negative staphylococci coexisted with P. aeruginosa in 10 cases and P. aeruginosa was also often associated with Enterococcus sp., Staphylococcus aureus, Streptococcus sp. or other species. Twelve cases carried P. aeruginosa more predominantly than the other species. Some coagulase-negative staphylococci, Enterococcus sp., S. aureus and Streptococcus sp. were also predominant. The frequency of predominant P. aeruginosa was significantly higher in secondary infections due to ulcers and decubitus than in secondary infections due to other skin diseases. P. aeruginosa was also often detected in the legs and feet, but not in the trunk. This organism showed high sensitivities to antibiotics, except minocycline. No significant differences in sensitivity or resistance to antibiotics were found between P. aeruginosa when detected as the predominant or single strain and this microorganism when detected as the non-predominant strain. Thus, the detection of P. aeruginosa important in choosing the appropriate antibiotics to be used and this is sometimes influenced by the patient's condition.

Adult↗
PubMed2001

Effect of lipase activities of Propionibacterium granulosum and Propionibacterium acnes.

We studied the lipase activities of Propionibacterium granulosum, P. acnes and the suppression of these activities by Jumi-haidoku-to (JHT). Lipase activity of P. acnes biotype III (BIII) was strongest, while that of P. granulosum was faintly expressed. Compared with the control medium, the production of propionic and butyric acids was suppressed by all the tested mediums combined with JHT. The decrease in these acids produced by JHT was significantly higher in P. granulosum than in P. acnes. Although P. acnes BIII may produce a strong effect on acne, the presence of P. granulosum should not be ignored. Further research is required on the correlation between P. acnes and P. granulosum.

Culture Media↗
PubMed2000

An ultrastructural study of pigmented purpuric dermatitis with special reference to fibrous long-spacing collagen.

A case of pigmented purpuric dermatitis (PPD) in a Japanese man aged 59 years is reported with an interesting ultrastructural finding. Clinically, the lesions, which consisted of telangiectatic puncta and pigmentation, were irregular in shape and occurred predominantly on the lower legs without pruritus. Histologically, lymphocytic perivascular infiltrates and extravasation of red blood cells were observed in the papillary dermis. Ultrastructurally, endothelial cells with ovoid nuclei showed swelling and the lumen of the capillary became narrowed. Several banded structures, so-called fibrous long-spacing collagen (FLSC), were observed in the cytoplasm. They were spindle shaped, about 5 microm in length, and showed crossbands of 300-nm-wide intervals with fine intraperiodic bands. These structures were not observed in dermal connective tissue and fibroblasts. These results suggested that FLSC was synthesized in endothelial cells rather than being phagocytosed by endothelial cells, which might be helpful in investigating the etiology of PPD.

Collagen↗
PubMed2000

Characterization of acyclovir susceptibility and genetic stability of varicella-zoster viruses isolated during acyclovir therapy.

We have characterized the susceptibility and genetic stability of varicella-zoster viruses (VZV) isolated from skin lesions of three patients with herpes zoster and six patients with varicella treated with conventional short-term acyclovir (ACV) administration. The susceptibilities to ACV of the serial isolates from the patients were examined, and there was no significant difference in the susceptibility to ACV among the isolates before and during the ACV treatment, indicating that conventional short-term ACV treatment did not generate ACV-resistant VZV infections. Polymerase chain reaction (PCR) analyses of these as well as seven thymidine kinase-deficient VZV strains derived from in vitro ACV treatment were carried out to examine their genomic stability. Five regions containing tandem direct reiterations (R1-R5) were amplified by PCR and compared, and the region containing the Pst I-site was also examined. PCR analyses demonstrated that the R1, R5 and the Pst I-sites were stable and useful in epidemiological studies even after ACV treatment. The R2, R3 and R4 sites were far less stable in these experimental conditions. In this paper we discuss the results of the PCR analyses with regard to the dynamics of VZV population in patients with VZV infection treated with conventional short-term ACV administration.

Acyclovir↗
PubMed2000

CD30 expression on circulating memory CD4+ T cells as a Th2-dominated situation in patients with atopic dermatitis.

Th2 clones have been reported to express CD30 preferentially, but whether T cells producing Th2-type cytokines may favor CD30 expression in the in vivo state remains unknown. We investigated the expression of CD30 on circulating T cells in atopic dermatitis (AD) as a Th2-dominated disorder. Peripheral blood mononuclear cells were prepared from 51 AD patients and 14 nonatopic controls, and their phenotypes were analyzed with flow cytometry. Cytokine production by stimulated CD4+ T cells was also assessed by the single-cell-staining method. Flow cytometric analysis clearly revealed that CD30+ T cells were identifiable in the blood of AD patients with greater frequency compared to controls. The important finding was that CD30 expression was restricted to a small but substantial population of memory (CD45RO+) CD4+ T cells, but not CD8+ ones. In AD patients, it was demonstrated that the percentages of CD30+ cells within CD45RO+ CD4+ T cells correlated well with the disease severity, serum IgE levels, peripheral eosinophil counts, and tendency toward Th2-dominant cytokine pattern as determined by the ratio of interleukin-4 to interferon-gamma production. This study suggests that CD30 expression in circulating T cells might serve as an in vivo marker for the Th2-dominated condition.

Adolescent↗
PubMed2000

A case of localized follicular hamartoma: an ultrastructural and immunohistochemical study.

We report the case of a 22-year-old woman with a nevoid plaque that we termed localized follicular hamartoma. The plaque was noticed at puberty on a unilateral site of the face and scalp. Clinically, it revealed numerous, skin-colored to light brown papules alone and in groups, occasionally bearing a single hair. Histologically, branched epithelial nests of squamoid and/or basaloid cells were revealed in connection with the interfollicular epidermis and the upper portions of hair follicles, of which the lower portions showed normal structures. Immunohistochemically, the epithelial nests showed the keratin expression consisted with that of the infundibular epithelium. S-100-positive cells were found in the epithelial nests and the stroma. Factor XIIIa-positive dendritic cells were numerous in adjacent to the epithelial nests. Ultrastructurally, immature melanocytes with a small number of premelanosomes and Merkel cells were found in the nests. Stromal dendritic cells showed the adherent features of the cytoplasmic processes to anchoring fibrils or basal lamina of the epithelial nests. From these findings, our case is a hamartoma, which seems to be an abortive growth of secondary hair germs with a limited differentiation to the upper follicular portion.

Adult↗
PubMed2000

Immunohistochemical localization of ornithine decarboxylase in skin tumors.

BACKGROUND: Ornithine decarboxylase (ODC) plays an important role in the biosynthesis of polyamines. Induction of ODC and polyamine synthesis has been demonstrated in neoplastic tumors and is thought to be related to the degree of malignancy. METHODS: In this study, we investigated a series of basal cell epitheliomas (BCE), Bowen's disease, squamous cell carcinomas (SCC), and metastatic tumors of the skin using an antibody against ODC for immunohistochemistry. RESULTS: Eight of 12 cases of BCE failed to show a positive reaction for ODC. In Bowen's disease, 5 of 13 cases diffusely showed positive reaction for ODC. Fourteen of 15 cases of SCC showed ODC expression, the intensity of which was decreased in the peripheral layer. At higher magnification, the distribution of ODC in the positive SCC cases showed granular and heterogenous patterns. Ten of 14 cases of metastatic skin tumors exhibited positive reactions, and well-differentiated adenocarcinomas tended to show more strongly positive than poorly-differentiated ones. CONCLUSIONS: These results support the conclusion that the intensity and the incidence of positive immunohistochemical staining for ODC correlate with the degree of cellular differentiation, and furthermore, that heterogenous distribution of ODC staining may be associated with heterogeneity of tumor cells.

Bowen's Disease↗
PubMed2000

Alopecia mice derived from albino ddY mice: breeding, histological and ultrastructural studies.

Sparse-haired (SH) mice arose spontaneously in a stock of sib-mated albino ddY mice. Hair loss in the skin of SH mice begins at 3 weeks of age and progresses with age. On the basis of breeding studies between SH mice and albino ddY mice, the phenotype of SH mice is identified as autosomal recessive inheritance. Histological examination shows that numerous pilary canals begin to widen and the outer root sheath becomes thin at 1 week of age. The inner root sheath and the hair were separated. Ultrastructural examination reveals that electron dense materials which formed coalesced and irregularly coiled chains are seen at the level of firm attachment of the hair to its inner root sheath. At the level of hair and inner root sheath separation, linear materials with high electron density are observed in the exocuticle of the hair cuticle. These results suggest that the appearance of electron dense materials is closely related to the mechanism of hair loss in SH mice and SH mice may be useful as an animal model in human hypotrichosis.

Alopecia↗
PubMed2000

Correlation between Propionibacterium acnes biotypes, lipase activity and rash degree in acne patients.

We examined the possible correlation between biotypes of Propionibacterium acnes, lipase activity, and rash degree in acne patients. Among 5 P. acnes biotypes, P. acnes biotype 3 (B3) was the most common, followed by P. acnes biotypes 1, 2 and 4; P. acnes biotype 5 was not found. P. acnes B3 was isolated from more severe skin rashes than those of the other biotypes. Production of propionic acid (PA) and butyric acid (BA) by P. acnes B3 was higher than those by the other P. acnes biotypes. As the rash degree in acne patients was more severe, the production of PA and BA elevated. Although only a few P. acnes strains were examined in the present study, P. acnes B3 had the highest lipase activity and might have the greatest influence on skin rash in acne patients.

Acne Vulgaris↗