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Biomedical subjects

M Asahi

Publications and source records attributed to M Asahi.

At least 19 recordsLinked to original sources
PubMed2001

[A case of autoimmune progesterone dermatitis].

A 41-year-old Japanese woman came to our clinic complaining of multiple edematous erythemas on the trunk and legs. The eruptions recurred periodically in association with the menstrual cycle. She had received oral progesterone therapy between 24 and 34 years of age. There were no abnormal values found in the routine and hormonal examinations, including progesterone and estrogen levels in serum and urine. After an intradermal skin test with progesterone, she had no reaction after 20 minutes but a positive reaction after 48 hours.

Adult↗
PubMed2001

Effects of matrix metalloproteinase-9 gene knock-out on the proteolysis of blood-brain barrier and white matter components after cerebral ischemia.

Deleterious processes of extracellular proteolysis may contribute to the progression of tissue damage after acute brain injury. We recently showed that matrix metalloproteinase-9 (MMP-9) knock-out mice were protected against ischemic and traumatic brain injury. In this study, we examined the mechanisms involved by focusing on relevant MMP-9 substrates in blood-brain barrier, matrix, and white matter. MMP-9 knock-out and wild-type mice were subjected to transient focal ischemia. MMP-9 levels increased after ischemia in wild-type brain, with expression primarily present in vascular endothelium. Western blots showed that the blood-brain barrier-associated protein and MMP-9 substrate zonae occludens-1 was degraded after ischemia, but this was reduced in knock-out mice. There were no detectable changes in another blood-brain barrier-associated protein, occludin. Correspondingly, blood-brain barrier disruption assessed via Evans Blue leakage was significantly attenuated in MMP-9 knock-out mice compared with wild types. In white matter, ischemic degradation of the MMP-9 substrate myelin basic protein was significantly reduced in knock-out mice compared with wild types, whereas there was no degradation of other myelin proteins that are not MMP substrates (proteolipid protein and DM20). There were no detectable changes in the ubiquitous structural protein actin or the extracellular matrix protein laminin. Finally, 24 hr lesion volumes were significantly reduced in knock-out mice compared with wild types. These data demonstrate that the protective effects of MMP-9 gene knock-out after transient focal ischemia may be mediated by reduced proteolytic degradation of critical blood-brain barrier and white matter components.

Actins↗
PubMed2001

Matrix metalloproteinase 2 gene knockout has no effect on acute brain injury after focal ischemia.

Matrix metalloproteinases (MMPs) may contribute to tissue damage after cerebral ischemia. In this study, wildtype and MMP-2 knockout mice were subjected to permanent and transient (2 h) occlusions of the middle cerebral artery. Gelatin zymography showed that MMP-9 levels were increased in all brains after ischemia. MMP-2 levels did not show a significant increase in wildtype mice, and were not detectable in knockout mice. Laser doppler flowmetry demonstrated equivalent ischemic reductions in perfusion in wildtype and knockout mice. In both permanent and transient occlusion paradigms, there were no statistically significant differences between wildtype and knockout mice in terms of 24 h ischemic lesion volumes. These data suggest that MMP-2 does not contribute to acute tissue damage in this model of focal ischemia.

Animals↗
PubMed2001

Phospholamban domain IB forms an interaction site with the loop between transmembrane helices M6 and M7 of sarco(endo)plasmic reticulum Ca2+ ATPases.

Transmembrane helix M6 of the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) has been shown to form a site of interaction with phospholamban (PLN). Site-directed mutagenesis was carried out in the cytoplasmic loop (L67) between M6 and M7 in SERCA1a to detect other SERCA-PLN binding sites. Mutants N810A, D813A, and R822A had diminished ability to interact functionally with PLN, but only D813A and R822A had reduced physical interaction with PLN. PLN mutants R25A, Q26A, N27A, L28A, Q29A, and N30A had enhanced physical interaction with wild-type (wt) SERCA1a, but physical interaction of these PLN mutants with SERCA1a mutants D813A and R822A was reduced about 2.5 fold (range 1.44-2.82). Exceptions were the interactions of PLN N27A and N30A with SERCA1a D813A, which were reduced by 7.3- and 5.8-fold, respectively. A superinhibitory PLN deletion mutant, PLNDelta21-29, had strong physical interactions with SERCA1a and with SERCA1a mutant D813A. Physical interactions with SERCA1a and mutant D813A were sharply diminished, however, for the PLN deletion mutant, PLNDelta21-30, lacking PLN N30. Physical interactions between SERCA1a and a PLN-cytochrome b(5) chimera containing PLN residues 1-29 were much stronger than those between a PLN-cytochrome b(5) chimera containing PLN residues 1-21 and lacking N27. These results suggest that a SERCA1-PLN interaction site occurs between L67 of SERCA1a and domain IB of PLN, which involves SERCA1a D813 and PLN N27 and N30.

Binding Sites↗
PubMed2001

Sonic hedgehog facilitates dopamine differentiation in the presence of a mesencephalic glial cell line.

The aim of this study was to establish a cellular system to investigate the requirement for cell surface and diffusible molecules in the differentiation of fetal mesencephalic cells toward the dopamine lineage. Toward this end, we immortalized rat embryonic day 14 (E14) mesencephalon with a regulatable retroviral vector encoding v-myc. The stably transduced cells were pooled and designated as VME14 cells. VME14 cells proliferated rapidly, stopped proliferating, extended processes, and expressed GFAP after suppression of the v-myc expression with tetracycline, suggesting that VME14 cells differentiated into glial cells. Dissociated cells derived from the E11 rat mesencephalon gave rise to only a small number of tyrosine hydroxylase (TH)-positive neurons. However, when grown on a monolayer of the differentiated VME14 cells, a significantly higher number of cells differentiated into TH-positive neurons. VME14 cells were transduced with the secreted N-terminal cleavage product of the Sonic hedgehog gene (SHH-N), an inducer of mesencephalic dopaminergic neurons. This monoclonal, SHH-N-overexpressing cell line further enhanced dopaminergic differentiation of E11 rat mesencephalon cells. Thus, SHH-N and signals derived from fetal mesencephalic glia act cooperatively to facilitate dopaminergic differentiation. These fetal mesencephalon-derived cell lines will provide tools for the study of signals involved in dopaminergic differentiation.

Animals↗
PubMed2001

Protective effects of pamiteplase, a modified t-PA, in a rat model of embolic stroke.

The effects of alteplase (tissue plasminogen activator, t-PA) and pamiteplase (a modified t-PA with longer half-life and increased potency) were compared in a clinically relevant model of embolic stroke. Rats were treated with pamiteplase (0.5 mg/kg or 1 mg/kg bolus), alteplase (10 mg/kg infusion) or normal saline. Pamiteplase (1 mg/kg) was as effective as alteplase in reducing 24 h brain infarct volumes, neurological deficit scores and residual clot grades. Cerebral blood flow recovery at 30 min after thrombolytic treatment was partial and did not correlate with 24 h infarct volumes or neurological deficits. However, there was good correlation between 24 h residual clot grades and infarct volumes, suggesting a delayed timeframe for pamiteplase- and alteplase-induced reperfusion.

Animals↗
PubMed2001

[A case of pemphigus foliaceus associated with bullous impetigo successfully treated with tetracycline and nicotinamide].

A 50-year-old Japanese woman visited our clinic, complaining of generalized erythema with painful erosions and bullae. The histopathological findings of the skin lesion suggested development of impetigo. Gentamycin-resistant Staphylococcus aureus was detected by the bacterial culture examination from the impetiginous bullae. A direct immunofluorescence study of the lesion showed an intercellular deposition of IgG and C3 in the upper epidermis. We diagnosed this case as pemphigus foliaceus associated with bullous impetigo. A combined oral administration of tetracycline (200 mg/day) and nicotinamide (1200 mg/day) for 3 weeks was successful. In Japan, patients with moderate to severe symptoms of pemphigus foliaceus are usually treated with oral steroid therapy. To our knowledge, however, there is no reported pemphigus case which has been successfully treated only with tetracycline and nicotinamide.

Anti-Bacterial Agents↗
PubMed2001

Immunohistochemical analysis of metallothionein expression in malignant melanoma in Japanese patients.

Recently, Zelger et al. found that metallothionein expression in melanoma is a useful prognostic indicator in white patients. In this study, we evaluated metallothionein expression in patients with melanoma as a prognostic indicator. We studied the tumors of 44 patients with cutaneous melanoma seen in our clinic from July 1988 to August 1998. Twenty-five neoplasms were metallothionein-positive, and 19 were metallothionein-negative. Only 9 (37.5%) of 24 cases of level I through III melanoma were positive for metallothionein, but 16 (80%) of 20 level IV and V cases were positive. Eight (40%) of 20 cases of "thin" melanoma (thickness: < or = 1.5 mm) were metallothionein-positive, and 17 (70.8%) of 24 cases of "thick" melanoma (thickness: > 1.5 mm) were metallothionein-positive. These results indicate a strong correlation of metallothionein expression with the level of invasion and tumor thickness in melanoma. The survival distribution function curve (Kaplan-Meier) for metallothionein expression showed a much better survival rate in the metallothionein-negative group than in the metallothionein-positive group.

Adolescent↗
PubMed2001

Delayed rt-PA treatment in a rat embolic stroke model: diagnosis and prognosis of ischemic injury and hemorrhagic transformation with magnetic resonance imaging.

The authors characterized effects of late recombinant tissue plasminogen activator (rt-PA) administration in a rat embolic stroke model with magnetic resonance imaging (MRI), to assess potential MRI correlates, or predictors, or both, of rt-PA-induced hemorrhage. Diffusion-, perfusion-, and postcontrast T1-weighted MRI were performed between 4 and 9 hours and at 24 hours after embolic stroke in spontaneously hypertensive rats. Treatment with either rt-PA or saline was started 6 hours after stroke. A spectrophotometric hemoglobin assay quantified hemorrhage severity. Before treatment, relative cerebral blood flow index (rCBFi) and apparent diffusion coefficient (ADC) in the ischemic territory were 30% +/- 23% and 60% +/- 5% (of contralateral), respectively, which increased to 45% +/- 39% and 68% +/- 4% 2 hours after rt-PA. After 24 hours, rCBFi and ADC were 27% +/- 27% and 59 +/- 5%. Hemorrhage volume after 24 hours was significantly greater in rt-PA-treated animals than in controls (8.7 +/- 3.7 microL vs. 5.1 +/- 2.4 microL, P < 0.05). Before rt-PA administration, clear postcontrast T1-weighted signal intensity enhancement was evident in areas of subsequent bleeding. These areas had lower rCBFi levels than regions without hemorrhage (23% +/- 22% vs. 36% +/- 29%, P < 0.05). In conclusion, late thrombolytic therapy does not necessarily lead to successful reperfusion. Hemorrhage emerged in areas with relatively low perfusion levels and early blood-brain barrier damage. Magnetic resonance imaging may be useful for quantifying effects of thrombolytic therapy and predicting risks of hemorrhagic transformation.

Animals↗
PubMed2001

Six cases of metastatic malignant melanoma with apparently occult primary lesions.

We report here six cases of malignant melanoma in which metastatic lesions were detected first. Of these, two cases showed some peculiar features: one exhibited widespread subcutaneous bleeding, probably due to venous rupture, and the other case had a rare primary lesion on the penis. In the Japanese literature, there have been 46 cases of malignant melanoma in which metastatic lesions were detected prior to the initial ones. The preferential site for metastasis was the lymph node (32 cases). The primary lesion was unknown in 35 patients. The outcomes were available for 36 of the 46 patients; 23 died, including 18 who died within two years.

Aged↗
PubMed2001

Ionic mechanisms underlying burst firing of layer III sensorimotor cortical neurons of the cat: an in vitro slice study.

We examined the ionic mechanisms underlying burst firing in layer III neurons from cat sensorimotor cortex by intracellular recording in a brain slice. Regular spiking was observed in 77.4% of 137 neurons in response to constant intracellular current pulses of 0.5- to 1-s duration. The rest of the neurons showed burst firing. An initial burst followed by regular-spike firing was seen in 71.0% of 31 bursting neurons. The rest of the bursting neurons (n = 9) exhibited repetitive bursting. In the bursting neurons, spikes comprising the burst were triggered from the afterdepolarization (ADP) of the first spike of the burst. We examined the ionic mechanisms underlying the ADP by applying channel-blocking agents. The ADP was enhanced (rather than blocked) by Ca2+ channel blockade. This enhancement of the ADP by Ca2+ channel blockade was apparent even after blockade of the afterhyperpolarization by apamin or intracellular Ca2+ chelation by EGTA. The firing rate of the regular-spiking cells was increased by apamin, intracellular EGTA or Ca2+ channel blockers. In 17.9% of the neurons examined (n = 56), these agents switched the regular-spiking pattern into a bursting one. Burst firing could not be changed to regular spiking by these agents. Four neurons that responded with a single initial burst in control solution responded with repetitive bursting after application of these agents. We conclude that the main function of Ca2+ influx in layer III neurons is to activate Ca2+-dependent K+ conductance, which prevents or limits burst firing. At a time when spike amplitude was unchanged, the ADP was blocked and the burst firing changed to regular spiking by extracellularly applied tetrodotoxin (TTX) or intracellularly applied N-(2,6-dimethylphenylcarbamoylmethyl) triethyl ammonium bromide (QX314). We concluded that a TTX- and QX314-sensitive Na+ current underlies the ADP and therefore contributes to the burst firing of layer III neurons from the cat cortex.

Action Potentials↗
PubMed2001

Proteus syndrome.

A case of Proteus syndrome is presented, in which severe hemihypertrophy of the left trunk and left lower extremity, scoliosis, endometriosis and huge bizarre-shaped body tumors were observed. Up to 22.6 kg of tumorous tissue was excised. This syndrome was first described in 1983. The name Proteus comes from a Greek mythical sea god who was able to change his body form freely. This syndrome has numerous features including hemihypertrophy, macrodactyly, various subcutaneous masses, scoliosis and other minor abnormalities. Although diagnostic criteria have been established for Proteus syndrome, which is very difficult to differentiate from other congenital hamartomatous syndromes, more case reports are needed to define such a rare disorder. Our patient is the 6th Japanese case in the English literature.

Adolescent↗
PubMed2001

[Evaluation of dermatological symptoms of Yusho patients in the annual examination in 1999-2000].

We analyzed the severity grades of the skin symptoms of Yusho patients who visited the annual examinations in 1999 and 2000. The severity grades of the skin symptoms clearly improved. The patients graded as 0 increased and those graded as II.III-III or III.IV-IV decreased as compared to the data in 1993. The pattern of the skin severity scores did not change much, although the patients who showed 0.1 reached 68% in 2000. The blood PCB concentration of Yusho patients also clearly decreased, especially in the patients who showed "A" pattern. Furthermore, the skin changes of the aged patients should be analyzed in detail in the future.

Female↗
PubMed2000

[Occupational contact dermatitis in women].

In work in which women predominate, the highest rate of the occupational contact dermatitis is seen among hairdressers and medical nursing staffs. Twelve such cases are presented and several points regarding the diagnosis and treatments are discussed. The patients were five hairdressers, two dental technicians, two nurses and three woman divers. A patch test was useful in identifying the allergens or irritants in most cases.

Adolescent↗
PubMed2000

Effects of matrix metalloproteinase-9 gene knock-out on morphological and motor outcomes after traumatic brain injury.

Matrix metalloproteinases (MMPs) belong to a class of extracellular proteinases responsible for maintaining and remodeling the extracellular matrix. In addition to multiple functions in normal physiology, abnormal MMP expression and activity may also participate in the pathophysiology of cerebral disease. Here, we show that MMP-9 (gelatinase B; EC.3.4.24.35) contributes to the pathophysiology of traumatic brain injury. After controlled cortical impact in mice, MMP-9 was increased in traumatized brain. Total MMP-9 levels at 24 hr were significantly increased as measured by a substrate cleavage assay. Zymograms showed that MMP-9 was elevated as early as 3 hr after traumatic brain injury, reaching a maximum at approximately 24 hr. Increased MMP-9 levels persisted for up to 1 week. Western blot analysis indicated increased profiles of MMP-9 expression that corresponded with the zymographic data. Knock-out mice deficient in MMP-9 gene expression were compared with wild-type littermates in terms of morphological and motor outcomes after trauma. Motor outcomes were measured at 1, 2, and 7 d after traumatic brain injury by the use of a rotarod device. MMP-9 knock-out mice had less motor deficits than wild-type mice. At 7 d, traumatic brain lesion volumes on Nissl-stained histological sections were significantly smaller in MMP-9 knock-out mice. These data demonstrate that MMP-9 contributes to the pathophysiology of traumatic brain injury and suggest that interruption of the MMP proteolytic cascade may be a possible therapeutic approach for preventing the secondary progression of damage after brain trauma.

Analysis of Variance↗
PubMed2000

[Occupationally induced hydrofluoric acid burns: an analysis of 9 patients from the aspect of occupational health].

We report here 9 patients suffering from hydrofluoric acid burn who visited our clinic from July, 1979 to February, 2000. These 9 cases occupied 25% of all chemical burn cases experienced in our clinic. All the patients were men ranging in age from 20 to 53 (mean age 35 years; average 36.8 years). At the time of accidental exposures, 6 patients had been engaged in washing or cleaning work, and 2 had been changing the parts of instruments containing hydrofluoric acid. Eight patients received burns on the hands and/or fingers. During the work, 2 patients had used vinyl chloride or rubber gloves, but three patients employed no protection for the hands. After the symptoms began to develop, it was found that the glove of one patient had a pin hole. Coupled with the occasions described in previous reports, the causal factors of hydrofluoric acid burn could be divided as follows: 1) negligence or carelessness of workers, in particular skilled persons, in handling hydrofluoric acid, 2) ignorance of the dangerousness of hydrofluoric acid, 3) the presence of pin hole (s) in protection gloves, and 4) unexpected accident. Hydrofluoric acid is one of the most corrosive inorganic acids, and can produce progressive and serious tissue necrosis with severe pain. To prevent burns due to this chemical, enlightenment and reeducation of the workers regarding the hazard of hydrofluoric acid are necessary.

Accidents, Occupational↗
PubMed2000

[A case of occupational contact dermatitis due to hydroxylamine].

A 36-year-old man, working in a chemical industry, had a generalized pruritic eruption. A forty-eight hour patch test revealed positivity for 1% hydroxylamine. Prevention of exposure to this chemical resulted in a dramatic improvement of the symptoms. Based on these findings, we diagnosed this case as occupational contact dermatitis due to hydroxylamine. There has been few case reports of contact dermatitis due to hydroxylamine. Histopathological examination revealed a marked spongiosis and a spongiotic bulla formation in the epidermis and follicular infundibulum, suggesting an allergic reaction.

Adult↗