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Biomedical subjects

H Yagi

Publications and source records attributed to H Yagi.

At least 181 records · Page 10Linked to original sources
PubMed1994

Effects of fibroblast growth factors and related peptides on food intake by rats.

The effects of acidic fibroblast growth factor (aFGF), basic FGF (bFGF), and related peptides, such as aFGF fragments, on food and water intake were investigated. Infusion of aFGF and bFGF into the third cerebral ventricle significantly suppressed food intake. The potency of aFGF was 1.5 that of bFGF in food intake inhibition. Both FGFs also suppressed water intake. Infusion of a carboxyl-terminal fragment of aFGF, aFGF-(114-140), did not affect food intake, whereas an amino-terminal fragment of aFGF, aFGF-(1-15), was significantly inhibitory. Other amino-terminal fragments, aFGF-(1-20) and aFGF-(1-29), did not affect food intake. However, [Ala16]aFGF-(1-29), in which the cysteine residue at position 16 was replaced with alanine, significantly suppressed food intake. Infusions of functional antagonists for FGFs, anti-aFGF, anti-bFGF, and anti-aFGF-(1-15) IgGs, into the lateral hypothalamus significantly increased food intake. The results suggest that: aFGF, bFGF, and some amino-terminal peptides of aFGF participate in the central regulation of food intake; the lateral hypothalamus is involved in their feeding suppression actions; and these peptides may function as physiologically relevant substances in the adult central nervous system, other than as neurotrophic factors.

Animals↗
PubMed1994

Acidic fibroblast growth factor facilitates generation of long-term potentiation in rat hippocampal slices.

In the present study, effects of acidic fibroblast growth factor (aFGF, 0.5-2.5 ng/ml) on synaptic transmission were investigated in rat hippocampal slices. Stimulation was applied to Schaffer collateral/commissural afferents and evoked spikes were recorded in CA1 pyramidal cell layer. Continuous perfusion of slices with aFGF slightly decreased the basal amplitude of the spikes and significantly increased the paired-pulse facilitation. When brief tetanic stimulation (7 impulses at 100 Hz) was applied 30 min after the perfusion of aFGF, aFGF-treated slices enhanced the magnitude of short-term potentiation after the tetanus and facilitated the generation of long-term potentiation. aFGF also enhanced post-tetanic potentiation directly after the tetanus. These effects of aFGF were dose-dependent. The enhancement of short-term potentiation and facilitation of the generation of long-term potentiation were not evident when aFGF was applied with or 10 min after the tetanus. The results suggest that aFGF is implicated in modulation of synaptic efficacy and can activate some mechanisms related to the generation of long-term potentiation.

Animals↗
PubMed1994

Evaluation of ultraviolet-A protection by sunscreen agents using a mouse model of contact photoallergy.

This study was conducted to investigate in vivo evaluation of protectiveness by sunscreens in the UVA range using a mouse model of contact photoallergy (CPS) to 3,3',4',5-tetrachlorosalicylanilide (TCSA). Mice were sensitized with TCSA painting plus UVA irradiation (TCSA/UVA) on the abdomen and, 5 days later, challenged with TCSA/UVA on the earlobe. Each of four sunscreen agents, benzophenone-3, Parsol 1789, p-aminobenzoic acid, and 2-ethyl-hexyl-p-methoxycinnamate, was applied to the earlobes before irradiation. Their protective efficacy was evaluated in the degree of inhibition of both ear swelling responses and TCSA-epidermal cell photoadduct formation. Two UVA-absorbing sunscreens, benzophenone-3 and Parsol 1789, dramatically inhibited the ear swelling response, while the two UVB-absorbers exhibited a much less suppressive effect. The UVA-absorbing agents functioned via inhibiting the formation of TCSA-epidermal cell photoadducts. This method is thought to be useful for in vivo estimation of UVA protection provided by sunscreens against the exquisite sensitivity involved in photoallergy.

Animals↗
PubMed1994

Disseminated pagetoid reticulosis: need for long-term follow-up.

A 54-year-old woman had an erythematous plaque on the left index finger for 2 years. Histologically there was a dense infiltrate of atypical mononuclear cells in the epidermis that produced a pagetoid appearance. A diagnosis of localized pagetoid reticulosis was made. Three years after total removal of the finger lesion, erythematous plaques appeared on her left thigh, followed by the development of similar plaques on the right thigh and lower abdomen. Histologically these skin lesions had the same pagetoid appearance as the plaque on the finger. This suggested development of the disseminated type of pagetoid reticulosis, long after removal of the initial skin lesion.

Diagnosis, Differential↗
PubMed1994

Mutagenic selectivity at the HPRT locus in V-79 cells: comparison of mutations caused by bay-region benzo[a]pyrene 7,8-diol-9,-10-epoxide enantiomers with high and low carcinogenic activity.

Earlier studies from our laboratories characterized the mutation profile of the optically active (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(+)-BPDE--the ultimate carcinogenic metabolite of benzo[a]pyrene] in the coding region of the hypoxanthine (guanine) phosphoribosyltransferase (HPRT) gene of Chinese hamster V-79 cells. In the present study, we evaluated the mutation profile of (-)-7S,8R-dihydroxy-9R, 10S-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene [(-)-BPDE-a weakly carcinogenic or inactive enantiomer] and compared its mutation profile with that of (+)-BPDE. In both diol epoxide enantiomers, the benzylic 7-hydroxy group and epoxide oxygen are trans. The mutation frequency for V-79 cells treated with DMSO vehicle or with a low, non-cytotoxic dose (0.5 microM) or a high cytotoxic dose (2.0 microM) of (-)-BPDE was 1, 25 or 185 8-azaguanine-resistant colonies/10(5) survivors, respectively. Independent 8-azaguanine-resistant clones were isolated, and complementary DNAs were prepared by reverse transcription. The coding region of the HPRT gene was amplified by the polymerase chain reaction and sequenced. Altogether, 92 (-)-BPDE-induced mutant clones were examined. At both doses, base substitutions were the most prevalent mutations observed (present in approximately 7% of the mutant clones), followed by exon deletions (present in approximately 22% of the mutant clones) and frame shift mutations (present in approximately 6% of the mutant clones) in the cDNAs analyzed. At the high cytotoxic dose, 5 out of 36 base substitutions occurred at AT base pairs (14%) and 31 at GC base pairs (86%). At the low, non-cytotoxic dose, 7 out of 34 base substitutions were at AT base pairs (21%) and 27 were at GC base pairs (79%). Although there was a trend towards an increase in the proportion of mutations at AT base pairs when the dose of (-)-BPDE was decreased, this trend was not statistically significant. The data also indicated no dose-dependent differences in the kinds of base substitutions or exon deletions in cDNAs induced by (-)-BPDE. Ninety-one per cent of the (-)-BPDE-induced mutations that occurred at guanine were on the non-transcribed strand of DNA and 9% were on the transcribed strand. In contrast to these results, 50% of the (-)-BPDE-induced mutations that occurred at adenine were on the transcribed strand and 50% on the non-transcribed strand.(ABSTRACT TRUNCATED AT 400 WORDS)

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1994

Facial erythema and pigmentation as an initial manifestation of chronic graft-versus-host disease.

Two bone marrow transplant recipients developed chronic graft-versus-host disease, presenting with a mild erythematous, pigmented eruption only on the face three and ten months after transplantation. Histologically, the lesions showed liquefaction degeneration of basal keratinocytes and incontinence of melanin in the upper dermis with a mild infiltrate of T-lymphocytes. These findings suggest that such a facial eruption occasionally may represent an initial manifestation of chronic GVHD.

Adolescent↗
PubMed1994

Cutaneous T-cell lymphoma with massive co-infiltration of polyclonal B cells.

A 76-year-old man presented with a 3-month history of a cutaneous nodule on the right thigh. The tumour was composed of CD3+, large atypical cells, and CD20+, small normal-appearing cells. Flow cytometry showed that CD20+ cells outnumbered CD3+ cells. By Southern blot hybridization analyses, the malignant cells were shown to be of T-cell origin, because of the presence of rearranged bands for the beta chain of the T-cell receptor, but not for the immunoglobulin heavy chain. This case represents a T-cell lymphoma intermingled with a large number of non-neoplastic B cells.

Aged↗
PubMed1994

Accumulation of blood-borne horseradish peroxidase in medial portions of the mouse hippocampus.

The intracerebral distribution of intravenously injected horseradish peroxidase (HRP) in young adult DDD mice was examined. HRP-tetramethylbenzidine reaction products were observed in the medial portions of the hippocampus, particularly the medial CA1 region and medial dentate gyrus. Reaction products were observed in the subfornical organ in mice decapitated 5 min after HRP injection, and then also progressively more caudally in the medial portions of the hippocampus as postinjection survival time increased. These findings suggest that blood-borne macromolecules have ready access to the medial portions of the hippocampus, particularly the medial CA1 region and medial dentate gyrus.

Animals↗
PubMed1994

Accessory cell ability of Langerhans cells for superantigen is resistant to ultraviolet-B light.

We examined the effects of ultraviolet-B (UVB) irradiation on the accessory cell ability of Langerhans cells (LC) to induce a T-cell response to a superantigen, staphylococcal enterotoxin B (SEB). The ability of LC-enriched epidermal cells (LC-EC) to evoke a T-cell response to SEB was retained at the doses of UVB (up to 40 mJ/cm2) that profoundly affected the antigen-presenting function of LC-EC for a hapten, trinitrophenyl (TNP), and a protein antigen, conalbumin. Thus, the LC accessory function for superantigens is more resistant to UVB irradiation than that for ordinary antigens. This UVB resistance is presumably due to no requirement of antigen processing for superantigens as chemically fixed or chloroquine-treated LC-EC still retained their ability to induce T-cell responses to SEB. Higher doses of UVB (more than 60 mJ/cm2) reduced the accessory cell ability of LC-EC for SEB up to 50% of control. The addition of monoclonal antibodies against adhesion molecules between LC and T cells to the culture resulted in a substantial suppression of the T-cell response to SEB induced by nonirradiated LC-EC, while the UVB-irradiated LC-EC-induced T-cell response was not significantly blocked with these monoclonal antibodies. This suggested that the reduction of LC ability for superantigen by high doses of UVB is at least partly due to the impairment of adhesion molecules on LC by UVB irradiation.

Animals↗
PubMed1994

Afloqualone photosensitivity: immunogenicity of afloqualone-photomodified epidermal cells.

Afloqualone (AQ) is an oral muscle relaxant and evokes ultraviolet A (UVA)-induced photosensitivity dermatitis as a side effect. Histologic observations of the skin eruption suggest that AQ photosensitivity is mediated not only by phototoxic but also by photoallergic mechanisms. To address the immunological mechanisms of AQ photosensitivity, we examined the immunogenicity of AQ-photomodified epidermal cells in mice. Afloqualone was covalently coupled with bovine serum albumin by irradiation with UVA but not UVB. Because of this ability of AQ to photobind to protein, murine epidermal cells were easily modified with AQ by exposure to UVA. Subcutaneous inoculation of AQ-photomodified epidermal cells successfully induced an antigen-specific delayed-type hypersensitivity in mice. These findings suggest that AQ-photoderivatized epidermal cells are highly immunogenic and that photomodification of epidermal cells with AQ is an initial event to evoke AQ photosensitivity dermatitis.

Animals↗
PubMed1994

Different effects between antihypertensive drugs on nephrotic-range proteinuria in renovascular hypertension.

A 61-year-old man developed renovascular hypertension characterized by nephrotic-range proteinuria. When he was treated with a calcium channel blocker, glomerular filtration fraction was 0.26 and massive proteinuria ranging from 10 to 15 g/day persisted. An angiotensin-converting enzyme inhibitor markedly reduced the proteinuria to 1-2 g/day with a filtration fraction of 0.20. After the antihypertensive drug was switched to a beta-blocker, the filtration fraction was 0.23 and urinary protein excretion was 3-4 g/day. Blood pressure control was comparable by each drug. These findings suggest a role of intraglomerular hydraulic mechanism in the etiology of massive proteinuria in renovascular hypertension.

Adrenergic beta-Antagonists↗
PubMed1994

A case of bullous systemic lupus erythematosus.

We report a case of bullous systemic lupus erythematosus (SLE). The patient suddenly presented with a widespread blistering eruption on the trunk and neck during the course of treatment of SLE. A skin biopsy specimen showed subepidermal blisters, and direct immunofluorescence (IF) revealed deposition of IgA, IgG and IgM at the dermoepidermal junction. Indirect IF showed linear IgG deposition along the base of 1 M NaCl-split skin. Rapid resolution of the blisters occurred following treatment with dapsone 50 mg daily.

Child↗
PubMed1994

Pemphigus associated with metastatic carcinoid.

Patients with pemphigus are occasionally associated with neoplasms. We report a case of pemphigus with carcinoid. To our knowledge, this is the first case of coexistence of pemphigus and carcinoid.

Adult↗
PubMed1994

Familial congenital hypopituitarism with central diabetes insipidus.

Congenital hypopituitarism (CH) presenting with central diabetes insipidus is typically associated with midline facial deformities or ophthalmological abnormalities. We present three brothers with CH and central diabetes insipidus not associated with any of these predisposing conditions. All three subjects presented with clinical features typical for CH (neonatal hypoglycemia, short stature, protruding forehead, and microgenitalia). All had hypoplastic genitalia indicating in utero gonadotropin deficiency, and all had complete GH deficiency. One represented low levels of thyroid hormones and TSH, indicating central hypothyroidism. Water deprivation examination in two of the brothers demonstrated complete arginine vasopressin deficiency in one and partial deficiency in the other. Magnetic resonance imaging indicated absence of the pituitary stalk, severe hypoplastic anterior pituitary in all three brothers, and absence of any posterior pituitary gland in two of the three. The other sibling had an ectopic posterior pituitary. This first report of familial CH with central diabetes insipidus may represent a previously unknown midline anomaly and provide new insights into the genetic control of pituitary and hypothalamic development.

Antibodies↗
PubMed1994

[Quantitative flow-cytometric analysis of CD34-positive stem cells in peripheral blood stem cell harvests].

The percentage of CD34-positive cells (the CD34-positive rate) in peripheral blood stem cell harvests (PBSCH) was determined using two color flow cytometric methods, i.e., representation in a histogram (the histogram method) and the two-dimensional side scatter-fluorescence representation (the SSC-FL method). For all samples examined, the CD34-positive rate obtained using the histogram method was higher than that obtained using the SSC-FL method. This finding was probably due to the fact that some monocytes non-specifically reacted with anti-CD34 monoclonal antibody, and the histogram method could not distinguish these non-specifically stained cells from CD34-positive precursor cells. On the other hand, the SSC-FL method seemed to yield a more accurate measurement of the percentage of CD34-positive cells in PBSCH samples. Based on this finding, it is recommended that the histogram method, which is currently used at most commercial laboratories, be reviewed in favor of the SSC-FL method when the CD34-positive cell rate of PBSCH is to be determined.

Adolescent↗
PubMed1994

[The clinical application of quantitative computed tomography to osteoporosis and it's related disorders].

Bone mineral in spinal vertebral bone, using the methods of single and dual energy tomographies (SEQCT and DEQCT) were applied to the studies of osteoporosis. The measurement of bone mineral in spinal bone with DEQCT was useful for elimination of fat mass effect in bone marrow, but has poorer reprocibility and higher dose-expose of radioactivity, compared with these of bone mineral by the SEQCT method. Bone mineral in the third lumbar spine of osteoporosis patients without bone fracture was employed in the SEQCT method, indicated that bone loss was age dependent in both sex and bone mineral showed O level which might be influenced by the fat mass in the marrow. The fat mass in the marrow was age-dependent. Bone mineral, in addition to fat mass effect was evaluated to give a diagnosis of osteoporosis. Physical activity was responsible for an increase of bone mineral. The more disable physical activity life was, the more diminished bone mineral was. The role of bone mineral was rationally distributed, and unbalanced bone mineral disposition permitted to induction into the degenerative central nervous system. The measurement of bone mineral in the spinal bone by the SEQCT method made possible a diagnosis and prevention of osteoporosis and observation of the therapeutic effect and clinical course was possible in osteoporosis patients.

Absorptiometry, Photon↗