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Biomedical subjects

H Kohda

Publications and source records attributed to H Kohda.

At least 19 recordsLinked to original sources
PubMed1995

Scanning electron microscopic observations of extracted terminal hair follicles of the adult human scalp and eyebrow with special references to the bulge area.

Scanning electron microscopic studies of human terminal hair follicles of the scalp and eyebrow have previously been limited to the hair shaft. In this study we investigated EDTA-treated extracted whole hair follicles in which most of the basal cell surface of the outer root sheath was well preserved. In the bulge area of scalp follicles there were many knob-like or villous projections. These were located in some specimens on one side of the follicle, while in others they were located around the entire circumference of the follicle. These projections were thought to represent the anchoring points of the branched follicular end of the arrector muscles. Ring-like elevations with groove-like depressions above and below were also observed surrounding the entire follicle. These were thought to represent the track of circumfollicular arrector muscles which depressed the outer root sheath when they repeatedly contracted. Most anagen eyebrow follicles showed morphological variations in the bulge area such as lattice-window-like structures and undulation patterns. In telogen follicles, the bulge became indistinguishable from the clubbed end. The lower end of these telogen follicles showed irregularly shaped bulge areas, but did not show lattice-window-like structures or undulation patterns as observed in anagen follicles. Interestingly, a hole was found in some bulge areas of both anagen and telogen follicles. Serial vertical sections of follicles revealed invaginated areas, which seemed to correspond to the openings seen in whole mounts. In vertical sections of eyebrow follicles some keratinocytes of the outer root sheaths of the bulge area were seen to be melanized to various extents. This phenomen was independent of hair cycle phase.

Adult↗
PubMed1995

Merkel cells do not require trophic maintenance from the nerves in adult human skin.

A 34-year-old Japanese man with hereditary sensory neuropathy was examined to evaluate the distribution, density and inter-relationship between Merkel cells and peripheral nerves in the skin. An epidermal sheet of affected plantar skin showed numerous CAM 5.2-reactive Merkel cells, whereas PGP 9.5-reactive peripheral nerves were completely absent in the epidermis and dermis. These findings strongly suggest that Merkel cells do not require trophic maintenance from nerves in adult human skin.

Adult↗
PubMed1995

Cutaneous cysts of Gardner's syndrome are similar to follicular stem cells.

Cutaneous cysts from a patient with Gardner's syndrome were histopathologically studied in detail. The cysts were, by and large, indistinguishable from ordinary epidermal cysts. However, several distinctive features were found: 1) epidermal or trichilemmal keratinization, 2) mature sebaceous glands connected with the cyst wall, 3) hair matrix-like structures associated with dermal papilla cells, 4) pilomatricoma-like changes, 5) intraluminal masses or pericystic deposits of shadow cells variably accompanied with foreign body reaction, 6) foreign body reaction or masses of shadow cells lining completely eroded cysts, 7) the presumptive bulge area, and 8) epithelial islands adjacent to the cyst. Each cutaneous cyst showed a variable combination of the findings described above. Foci of the basal layer of some cyst walls or epithelial islands were immunohistochemically stained with CK19, where CK20-reactive Merkel cells were also present. These findings were consistent with those of the bulge area. Unexpectedly, desmin-reactive muscle bundles, presumably indicating arrector pili muscle, were observed along the cyst wall. Our observations suggest that Gardner's cysts may be derived from putative follicular stem cells which reside in the bulge area.

Adult↗
PubMed1995

Localized myxedema, associated with increased serum hyaluronic acid, and response to steroid pulse therapy.

A 66-year-old man presented with Graves' disease and widespread localized myxedema. Extensive lesions were present on the legs, feet, hands, and face. TSH receptor antibody (TBII) was markedly positive and the serum hyaluronic acid level was very high. Intravenous steroid pulse therapy was followed by oral therapy with gradual tapering. This regimen markedly improved the skin lesions and resulted in a decrease of the serum hyaluronic acid level. The findings suggest that steroid pulse therapy is effective for the treatment of extensive localized myxedema. In addition, the serum hyaluronic acid level may be a useful parameter for the follow-up of patients with this condition.

Administration, Oral↗
PubMed1994

Importance of cytotoxic T lymphocytes in the rejection of transplanted hepatocellular carcinoma.

Fischer rats became resistant to syngeneic hepatocellular carcinoma (FAA-HTC1) cells on repeated sensitization with mitomycin C-treated FAA-HTC1 cells. In contrast, FAA-HTC1 cells injected into the liver killed normal control Fischer rats within 2 months. Histopathological studies revealed massive accumulation of mononuclear cells in the tumor tissues of sensitized rats that rejected syngeneic FAA-HTC1 cells, whereas very few mononuclear cells were found in the tumor tissues of control rats. Cell populations infiltrating the tumor tissues were identified by flow cytometric analysis. Mononuclear cells found within the regressing tumors of the sensitized rats were identified as mostly T cells, and two-thirds of these T cells were CD8-positive. Compared with the activity in control rats, the killer activity of mononuclear cells infiltrating tumors was significantly increased in the sensitized rats 7 days after tumor inoculation. Depletion of CD8(+) T cells significantly reduced the cytotoxicity of mononuclear cells infiltrating tumors obtained from sensitized rats. In contrast, depletion of CD16(+) cells reduced the cytotoxicity of mononuclear cells infiltrating tumors obtained from both control and sensitized rats. Furthermore, the CD16(+) cell-depleted fraction of mononuclear cells infiltrating tumors showed significant cytotoxicity against FAA-HTC1 cells, but failed to show cytotoxicity against other syngeneic tumor cells or allogeneic hepatoma cells.

Animals↗
PubMed1994

Two- and three-dimensional observations of human terminal and vellus hair follicles.

Extracted human terminal and vellus hair follicles were prepared by EDTA and examined by light and electron microscopes. These samples were morphologically well preserved and enabled us to observe 3-dimensional (3-D) views of the outer surfaces of hair follicles. Interestingly, the bulge areas of terminal and vellus hair follicles showed several morphological variations, such as knob-like swellings and villous projections, independent of hair cycle. Moreover, skirt-like structures were furnished in the small vellus hair follicles independent of hair cycle, but not terminal and large vellus hair follicles. These morphological variations of human hair follicles were confirmed to genuinely represent 3-D views by means of the conventional transverse and vertical sections of the human skin.

Edetic Acid↗
PubMed1994

Immunohistochemical demonstration of keratin 19 expression in isolated human hair follicles.

We examined keratins 19 and 8 in extracted human hair follicles using monoclonal antibodies Ks19.1 and CAM5.2, respectively. Ks19.1 reactivity was found in the bulge and infundibulum. Ks19.1(+) cells were dense in the bulge of vellus and intermediate hair follicles. The intact bulge of terminal hair could not be extracted, but the presence of Ks19.1(+) cells was confirmed in transverse sections. Infundibular Ks19.1(+) cells exhibited a dense network pattern of staining in terminal hair follicle, but only a few cells were labeled in vellus and intermediate hair follicles. CAM5.2(+) cells, i.e., Merkel cells, were found in the same locations as Ks19.1(+) cells but were less dense. These patterns of distribution and staining density were not influenced by different phases of hair cycle. Sequential staining of Ks19.1 and CAM5.2 in the same hair follicle demonstrated that the same cells could be reactive for both. However, considering the large number of Ks19.1(+) cells and rather small number of CAM5.2 in the same locations, it was assumed that only a subset of Ks19.1(+) cells are Merkel cells. It was postulated that the bulge area of human adult hair follicles houses embryonic pluripotential cells characterized by stem cells and post-stem cells and that the Merkel cells in the bulge area arise from these immature cells and may play a role in the maintenance and stimulation of this group of immature cells.

Aged↗
PubMed1994

Immunohistochemical demonstration of the expression of neurofilament proteins in Merkel cells.

The presence of immunoreactive neurofilament proteins has previously been reported in Merkel cell carcinomas but not in normal human epidermal and dermal Merkel cells. We have studied the immunoreactivity of epidermal Merkel cells for neurofilament triplet proteins (68 KD, 70 KD, 160 KD, 200 KD), using epidermal sheets prepared from the plantar skin of human adults, which enabled us to survey large numbers of Merkel cells. Neurofilament protein 200 KD-positive cells were readily identified, while neurofilament protein 68 KD-, 70 KD- and 160 KD-positive cells were largely absent. 200 KD-positive cells in the epidermis were confirmed to represent Merkel cells by a sequential immunoenzyme labeling for the simple epithelial type cytokeratin (No. 8). 200 KD-positive cells were 5.9% of the total number of epidermal Merkel cells. Despite a heterogeneous expression of neurofilament protein subspecies between the normal and transformed Merkel cells, the presence of neurofilament proteins in epidermal Merkel cells may link them to Merkel cell carcinomas.

Adult↗
PubMed1993

Arrector pili muscles surround human facial vellus hair follicles.

Arrector pili muscles have been assumed to attach to one side of the hair follicle, specifically the posterior wall of the bulge area. In this study, we demonstrated immunohistochemically that desminreactive arrector pili muscle, admixed with the connective tissue sheath, is present around the entire circumference of the vellus hair follicle.

Connective Tissue↗
PubMed1992

Induction of Mn-superoxide dismutase by tumor necrosis factor, interleukin-1 and interleukin-6 in human hepatoma cells.

Effects of Tumor Necrosis Factor (TNF), Interleukin-1 (IL-1), Interleukin-6 (IL-6) and Interferon-gamma (IFN-gamma) on the expression of Mn-superoxide dismutase (Mn-SOD) protein were investigated in human hepatoma cells, Hu-H1, which revealed resistance to the cytotoxicity of TNF and IL-1. Both TNF and IL-1 enhanced the Mn-SOD production to the level of 30- to 40-fold. IL-6 also increased the enzyme protein to 2- to 3-fold of the basal level without any cell proliferative effect. A specific antibody against IL-6 almost completely inhibited the induction of Mn-SOD. IL-6, as well as TNF and IL-1, appears to play some role in the Mn-SOD protein expression in human hepatoma cells.

Antibodies↗
PubMed1992

The effect of IL-6 on the des-gamma-carboxy prothrombin synthesis in human hepatoma cells.

Effects of several cytokines on des-gamma-carboxy prothrombin (PIVKA II) synthesis in human hepatoma cells were investigated to know the process of PIVKA II production during a liver allograft rejection. Human recombinant interleukin-6 (IL-6) significantly stimulated the PIVKA II synthesis without any influence on the cell proliferation. The effect was almost completely neutralized by the specific anti-IL-6 antibody. Neither tumor necrosis factor (TNF), interleukin-1 (IL-1) nor interferon-gamma (IFN-gamma) had such a stimulative effect. IL-6 appears to stimulate PIVKA II production, and would be a candidate of factors that enhance the production of PIVKA II during a liver allograft rejection.

Biomarkers↗
PubMed1992

Diagnostic utility of magnetic resonance imaging in malignant melanoma.

BACKGROUND: Dermatologists sometimes have difficulty in making the diagnosis of a melanocytic tumor. OBJECTIVE: Our purpose was to establish a noninvasive method for the diagnosis of malignant melanoma. We investigated the diagnostic usefulness of magnetic resonance imaging (MRI) in 23 lesions of primary malignant melanoma, metastatic malignant melanoma, and benign pigmented skin tumors. METHODS: The morphologic characteristics and the signal intensity of the tumors were analyzed to differentiate malignant and benign pigmented skin tumors by means of the tumor-to-fat contrast ratio of the signal intensity. RESULTS: The morphologic characteristics of the tumors obtained by MRI were not an absolute criterion for diagnosis of malignant melanoma, but the signal intensity of the tumor assessed by the tumor-to-fat contrast ratio on T2-weighted images clearly differentiated between primary malignant melanoma and benign pigmented skin tumors. CONCLUSION: These findings indicated that MRI is useful for noninvasive diagnosis of malignant melanoma.

Diagnosis, Differential↗
PubMed1992

A unique case of extramammary Paget's disease. Derivation from eccrine porocarcinoma?

A unique case of extramammary Paget's disease is reported that may have derived from eccrine porocarcinoma. A palm-sized erythematous plaque on the patient's pubis spread to the lower abdominal wall. The center of the lesion contained a reddish tumor. Histologic findings of the erythematous plaque showed features of extra-mammary Paget's disease. Those of the reddish tumor, however, corresponded most closely to eccrine porocarcinoma, though we could not entirely rule out that the changes corresponded to larger nests of less differentiated Paget cells. The two distinct neoplastic areas showed continuity both clinically and histologically; our case differed from epidermotropic eccrine porocarcinoma in several clinicopathologic respects. Our case suggests the possibility that extramammary Paget's disease could arise from preexisting porocarcinoma.

Adenoma, Sweat Gland↗
PubMed1992

Digital verrucous fibroangioma: a new variant of verrucous hemangioma.

In this article, we report on 4 cases of a dome-shaped nodule on the dorsum of the finger, which had been present since birth and slowly enlarged. On light microscopic examination, these nodules showed similarities to verrucous hemangioma. However, they were characterized by distinct clinical features and proliferation of dermal connective tissue. We consider these tumors to be a variant of verrucous hemangioma and propose to term them digital verrucous fibroangioma.

Adolescent↗
PubMed1991

Pigmented macules on the palms and/or soles of Japanese subjects: influences of clinical severity and duration of illness.

We have suggested that pigmented macules on the palms and/or soles occur in response to various systemic diseases. In the present paper, we evaluated the influences of clinical severity and duration of illness in Japanese subjects. In males, cases who suffered from cerebral vascular accident (CVA) for long periods and/or severely tended to have numerous pigmented macules. In females, cases with CVA did not show any similar tendency. As the result of our prior and present studies, we conclude that underlying systemic disease itself can play a pivotal role in the development of pigmented macules on the palms and/or soles of Japanese subjects. We emphasize that such a pigmented macular eruption with characteristic clinical features is an important sign of internal disorders, including malignancy.

Activities of Daily Living↗