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Biomedical subjects

H Koizumi

Publications and source records attributed to H Koizumi.

At least 19 recordsLinked to original sources
PubMed1992

MR imaging of brain surface using steady-state free precession.

We present an imaging technique that affords direct and noninvasive visualization of brain surface structure. This technique utilizes the signal before the rf pulse in steady-state free precession. This signal highly reflects the spin-spin relaxation time T2 as was studied in our laboratory (Matsui et al. J. Magn. Reson. 62, 12, 1985). Therefore the cerebrospinal fluid (CSF), having a long T2, is depicted as high intensity. The CSF permeates cerebral sulci and fissures. The imaging time with this technique is less than 1 min.

Cerebral Cortex↗
PubMed1992

Perforin gene expression in stimulated human peripheral blood T cells studied by in situ hybridization and northern blotting analysis.

In situ hybridization was used here to monitor the mRNA level of the pore-forming protein perforin in mitogen-stimulated primary peripheral blood human T cells. In situ hybridization was performed using sense and antisense ribonucleotide probes specific for this granule mediator. After IL-2 treatment, an increase in perforin mRNA could be detected by 4 h; they peaked at 12 h, and decreased after 24 h. The perforin mRNA was also induced in T cells treated with a combination of phorbol ester PMA plus lectin or OKT3 mAb. This latter induction followed slower kinetics, peaking at 48 h. For all three mitogens used, even at peak induction times less than 10% of T cells were labeled with perforin probe. Similar patterns of mRNA expression were observed for both unprimed T cells and lectin-primed T blasts. The induction response of mRNA due to IL-2 stimulation is probably mediated by the IL-2 receptor p75 chain since its mRNA was upregulated by IL-2 with a kinetics comparable to that associated with an increase of perforin mRNA. The p55 IL-2 receptor chain increased much more slowly than p75.

Blotting, Northern↗
PubMed1992

Effects of novel synthesized retinobenzoic acid (Am-80) on adenylate cyclase and arachidonic acid release in pig epidermis.

It has been well established that the psoriatic hyperproliferative epidermis is characterized by a defective beta-adrenergic adenylate cyclase response and an increased arachidonic acid metabolism. Effects of a newly synthesized retinoid, Am-80 (4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)amino) carbamoyl]benzoic acid), on the beta-adrenergic adenylate cyclase response and on the arachidonic acid metabolism of pig epidermis were investigated. Am-80 augmented the beta-adrenergic adenylate cyclase response of the epidermis. The effect was observed at the concentrations of more than 1 microM. The maximum beta-adrenergic augmentation effect induced by Am-80 was similar to those of all-trans-retinoic acid and of hydrocortisone. Am-80 inhibited the basal arachidonic acid release as well as 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated arachidonic acid release from epidermal keratinocytes. The effect was observed at the concentrations of 50-100 microM. The inhibitory effect of Am-80 was similar to those of all-trans-retinoic acid and of hydrocortisone. Our results indicate that Am-80, a newly synthesized retinoid, reveals the beta-adrenergic adenylate cyclase response augmentation effect and the inhibitory effect on the arachidonic acid metabolism of the epidermis. These effects are consistent with a view that Am-80 is another retinoid which has significant pharmacological effects on keratinocytes.

Adenylyl Cyclases↗
PubMed1992

Localization of proteins immunologically related to erythrocyte protein 4.1, spectrin and ankyrin in thyroid gland.

Analogues of erythrocyte protein 4.1, spectrin and ankyrin were examined in the thyroid gland of pig and rat by immunohistochemical techniques. Analysis with immunofluorescence microscopy revealed that the peripheral cytoplasm and apical-lateral plasma membrane of follicle epithelial cells of thyroid glands were stained with antibodies against erythrocyte protein 4.1, spectrin, or ankyrin. The results indicate that membrane skeletal protein lattice might exist in thyroid follicle epithelial cells.

Animals↗
PubMed1992

An association of acanthosis nigricans and Crouzon syndrome.

An 11-year-old Japanese female having acanthosis nigricans associated with Crouzon syndrome is reported. Crouzon syndrome is a craniostenotic craniofacial malformation associated with premature closure of selective calvarial sutures, exophthalmos, maxillary hypoplasia, and a beak-shaped nose. It is an autosomal dominant inherited disorder. Crouzon syndrome is one of the syndromes which may be associated with acanthosis nigricans. The association of acanthosis nigricans with Crouzon syndrome is assumed to be a rare abnormality, although the true frequency is uncertain. We have reviewed the reported cases of acanthosis nigricans associated with Crouzon syndrome and characteristics were discussed.

Acanthosis Nigricans↗
PubMed1992

Triple cancers in the urogenital area of a patient with aplastic anemia.

Three epithelial neoplastic lesions, perineal Bowenoid papulosis, uterine cervical carcinoma, and bladder transitional cell carcinoma, which occurred in a mildly immunosuppressed patient who had aplastic anemia were studied for human papillomavirus (HPV) infection. In the Bowenoid papulosis, HPV type 16 DNA was identified by polymerase chain reaction (PCR) and by in situ hybridization (ISH). In contrast, in the uterine cervical carcinoma, HPV 16 was not detected, although possibly another unidentified type of HPV in the lesion was suggested by the ISH findings. In the bladder transitional cell carcinoma, neither papillomavirus genus-specific (PGS) antigen nor HPV DNA was found.

Adult↗
PubMed1992

Adenylate cyclase induces intracellular calcium increase in single human epidermal keratinocytes measured by fluorescence microscopy using Fura 2-AM.

Intracellular calcium ([Ca2+]i) is an important second messenger of extracellular signals to induce various cellular responses. Extracellular and intracellular Ca2+ are considered to be important for cellular differentiation and proliferation of epidermal keratinocytes. Several mechanisms which increase [Ca2+]i have been demonstrated in various tissues, but in epidermal keratinocytes these mechanisms are poorly understood. In epidermal keratinocytes the adenylate cyclase-cyclic AMP response is thought to regulate cell proliferation and differentiation. However, the series of reactions which follow the cyclic AMP response remain unknown. Beta-adrenergic agonists increase [Ca2+]i in cultured epidermal keratinocytes, and we have therefore studied whether stimulation of keratinocyte adenylate cyclase could induce [Ca2+]i increase, by using fluorescence microscopy with Fura 2-AM. Adenosine and histamine, which are known to be keratinocyte adenylate cyclase receptor agonists, induced transient [Ca2+]i increase, as did epinephrine. In addition, forskolin, a direct adenylate cyclase activator, and dibutyryl-cyclic AMP also induced an increase in [Ca2+]i. In a calcium-free medium epinephrine, adenosine, histamine and dibutyryl-cyclic AMP induced an increase in [Ca2+]i. These results suggest that cyclic AMP in human epidermal keratinocytes regulates [Ca2+]i, which is released from intracellular stores.

Adenosine↗
PubMed1992

Substance P induces intracellular calcium increase and translocation of protein kinase C in epidermis.

Substance P is a neuropeptide present in, and released from, peripheral C nerve endings. The presence of substance P-positive nerve fibres in the epidermis has been reported. We investigated the effect of substance P on the transmembrane signalling system of pig epidermal keratinocytes. Treatment of pig epidermis with substance P resulted in an increase in inositol 1,4,5-trisphosphate (IP3), and in intracellular free calcium. The treatment also resulted in translocation of protein kinase C from a cytosol to a membrane fraction. Substance P, however, did not affect the beta-adrenergic- or histamine (H2)- adenylate cyclase responses of the epidermis. Neither forskolin-induced, nor cholera toxin-induced cyclic AMP accumulation were affected by substance P treatment. These results consistent with the view that substance P stimulates phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis of keratinocytes, resulting in IP3-Ca2+ and diacylglycerol-protein kinase C signal activation. Although protein kinase C is known to affect the epidermal adenylate cyclase system, no evidence for such 'cross-talk regulation' was detected in keratinocytes by substance P treatment.

Animals↗
PubMed1992

Respiratory activities in relation to palatal muscle contraction.

This study investigated the activities of the tensor and levator veli palatini muscles related to respiration. During quiet breathing, no activity was observed in either muscle. With either hypercapnic or hypoxemic condition, the tensor veli palatini muscle exhibited phasic activity during inspiration. The levator veli palatini muscle showed phasic activity during expiration with hypoxemia (PaO2 less than 40 mm Hg). NaCN perfused bilaterally through the carotid sinus induced these respiratory activities. The tensor veli palatini muscle was more sensitive than the levator veli palatini muscle to NaCN.

Animals↗
PubMed1992

Adenosine deaminase activity in sera of patients with psoriasis, mycosis fungoides and adult T cell leukemia.

Adenosine deaminase activities in sera were measured in 18 psoriatic patients, 8 mycosis fungoides patients, and 9 patients with adult T cell leukemia. Adenosine deaminase activity in the sera of the psoriatic patients showed no significant increase. An elevated adenosine deaminase activity was observed in 7 of the 8 patients with mycosis fungoides and 8 of the 9 patients with adult T cell leukemia. After chemotherapy, adenosine deaminase activity in serum of acute adult T cell leukemia was reduced. Adenosine deaminase activity in the sera of 2 patients with smoldering adult T cell leukemia was more elevated, with exacerbation of the disease. It is difficult to grade the extension of the tumors in plaque stage mycosis fungoides and smoldering adult T cell leukemia. To know the progression of the disease is critical in determining its management. These results indicate that adenosine deaminase activity in serum is one of the reliable indicators for the grading of mycosis fungoides and adult T cell leukemia.

Adenosine Deaminase↗
PubMed1992

Intramuscular hemangioma in the digastric muscle.

Intramuscular hemangioma is a distinctly rare neoplasm originating within normal muscle. In the head and neck region, it occurs most frequently in the masseter muscle. Diagnosis of intramuscular hemangioma is extremely difficult because it is not encountered frequently and is often confused with salivary gland stone, parotid neoplasm or other tumors. In this report, a second case of intramuscular hemangioma of the digastric muscle and the diagnosis of this type of tumor in the early stage and the importance of its treatment are described.

Female↗
PubMed1992

[Effects of induced hypotensive anesthesia on the blood coagulation-fibrinolysis system measured by thrombelastography--comparison between prostaglandin E1 and trimethaphan].

The coagulation-fibrinolysis system has been studied in two groups of 16 patients classified ASA 1 undergoing radical mastectomy during controlled hypotensive anesthesia induced by prostaglandin E1 (PGE1) or by trimethaphan (TMP) under enflurane anesthesia. Thrombelastography (TEG) was used to evaluate both coagulation and fibrinolysis systems, while simultaneously measuring platelet aggregation in response to ADP and collagen, prothrombin time (PT), activated partial thromboplastin time (APTT), serum concentrations of fibrinogen, and platelet counts. In the PGE1 group, APTT was significantly shortened (P less than 0.05) while the drug was being infused, but there was no statistically significant difference between the two groups, which was considered due to the effect of enflurane. Also, no statistically significant changes were noted in the other measured parameters. These results suggest that controlled hypotensive anesthesia using either PGE1 or TMP under enflurane anesthesia produces no significant changes in the blood coagulation-fibrinolysis system and that both are useful for the management of bleeding during surgery. Further, TEG was found to reflect other parameters properly. It is therefore useful for monitoring the blood coagulation-fibrinolysis system during anesthesia.

Adult↗
PubMed1992

[An epidemiogenetic study of typical retinitis pigmentosa in Japan--a preliminary report of nationwide, multicenter study].

We performed a nationwide, multicenter study of typical retinitis pigmentosa with reference to the inheritance patterns of the disease. A total of 253 probands were registered during two months of 1989, and an analysis of the parental consanguinity of 182 probands with the method of inbreeding coefficient enabled us to estimate the relative prevalence of genetic types; autosomal recessive trait: 47.6%; autosomal dominant trait: 17.3%; sporadic cases: 34.6%. A comparison of the results with previous studies has indicated a decrease in the prevalence of the autosomal recessive trait and an increase in the sporadic cases, as would be expected from the decrease in consanguineous marriages and offsprings in the past few decades in Japan. X-linked retinitis pigmentosa was rarely identified, but precise evaluation of its frequency needs further investigation.

Adolescent↗
PubMed1991

Expression of perforin and serine esterases by human gamma/delta T cells.

gamma/delta T cells have recently been described in association with a number of disorders, including autoimmune diseases. gamma/delta T cells are thought to play a cytotoxic role, but their mechanism of action is not known. Several granule mediators of cytotoxicity, including a pore-forming protein (perforin), and a family of serine esterases, have been isolated from cytotoxic T lymphocytes (CTL), lymphokine-activated killer (LAK) cells, and natural killer (NK) cells. We demonstrate here that gamma/delta T cells also express these mediators. Northern blots show that gamma/delta T cells express perforin, serine esterase 1 (SE 1), and SE 2. Three polyclonal antisera - raised against murine perforin, a peptide composed of amino acids 1-34 of human perforin, and human peforin expressed in bacteria - all reacted with a 70-kD protein in gamma/delta T cells on Western blots. Immunostaining with antiperforin antisera shows that primary gamma/delta T cells also contain perforin. Electron microscopy reveals that the granules of gamma/delta T cells resemble those of CTL, LAK, and NK cells. Gamma/delta T cells also resemble LAK cells in possessing inclusion bodies in their nuclei. These results imply that gamma/delta T cells resemble other cytolytic lymphocytes in their mechanism of action.

Blotting, Northern↗
PubMed1991

Presence and localization of proteins immunologically related to erythrocyte protein 4.1 in human skin.

Analogues of human erythrocyte protein 4.1 have been examined in the human skin by immunochemical techniques using anti-human erythrocyte protein 4.1 antibodies. Immunoblot analysis revealed that human epidermis contains 4.1-like proteins of 80 kDa and 78 kDa that cross react with anti-protein 4.1 antibodies. Analysis with immunofluorescence microscopy revealed that the plasma membrane of the human epidermal keratinocyte was stained intensively in the basal cells, whereas spinous cells were moderately stained. It is noted that eccrine sweat gland cells and ductal cells were also stained in the peripheral cytoplasma. Taken together, these results demonstrate that 4.1-like proteins are present in human epidermal keratinocytes, eccrine sweat gland cells and ductal cells. The present findings enable us to suggest that a membrane skeletal protein lattice might exist in these cells.

Antibodies↗
PubMed1991

Adenylate cyclase induces intracellular Ca2+ increase in single human epidermal keratinocytes of the epidermal sheet as measured by digital imaging microscopy using Fura 2-AM.

Intracellular Ca2+ ([Ca2+]i) is thought to act as a second messenger of transmembrane signalling systems. However, no measurement of [Ca2+]i has been made in intact epidermal keratinocytes. We have developed a method for measuring [Ca2+]i in human keratinocytes from pure epidermal sheet by the application of digital imaging fluorescence microscopy with the use of Fura 2-AM. Normal human pure epidermal sheets were obtained by dispase treatment. Epinephrine and salbutamol induced transient [Ca2+]i increases. Propranolol, a beta-antagonist, inhibited this response, while prazosin and yohimbine (alpha 1- and alpha 2-antagonists, respectively) did not affect the response. Histamine and adenosine, also receptor agonists of the epidermal adenylate cyclase system, induced a similar [Ca2+]i increase, as did forskolin, a direct activator of adenylate cyclase. These data coincide with those previously presented for cultured human epidermal keratinocytes, and reveal that adenylate cyclase activation induces an increase of [Ca2+]i in intact epidermal cells. This technique enables the kinetics of [Ca2+]i in various skin disorders to be investigated.

Adenosine↗
PubMed1991

Apolipoprotein B is a major perforin inhibitor protein in human serum.

We purified the high-molecular-weight perforin inhibitor protein from normal human serum using DEAE-cellulose, HPLC-gel filtration and hydroxylapatite chromatography. This protein was shown to be identical to the serum apolipoprotein B-100 in terms of amino acid composition and the sequence of the digested peptides. This inhibitor protein not only inhibits the membrane binding activity of perforin but also the pore insertion activity of membrane-bound perforin.

Amino Acid Sequence↗