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Biomedical subjects

H Fujisawa

Publications and source records attributed to H Fujisawa.

At least 271 records · Page 15Linked to original sources
PubMed1991

Immunoelectron microscopic study of tyrosine hydroxylase immunoreactive nerve fibers and ganglion cells in the rat adrenal gland.

The present immunocytochemical study used an antiserum to tyrosine hydroxylase (TH), the first enzyme in the biosynthetic pathway of catecholamines, and revealed TH immunoreactivity in the ganglion cells and in the varicose nerve fibers of the cortex and medulla in the rat adrenal gland. TH immunoreactive nerve fibers in the cortex and medulla contained large and small granular vesicles, and also small clear vesicles. The immunoreactive nerve fibers were in close apposition to cortical cells in the cortex and in apposition to smooth muscle cells of blood vessels in both the cortex and medulla. Furthermore, TH immunoreactive nerve fibers were sometimes in close apposition to pericytes of blood vessels in the cortex and chromaffin cells in the medulla. The present results suggest that the catecholaminergic nerve fibers in the rat adrenal gland may be both intrinsic and extrinsic in origin.

Adrenal Glands↗
PubMed1991

Dissection of functional domains of the packaging protein of bacteriophage T3 by site-directed mutagenesis.

Intracellular phage T3 DNA is synthesized as a concatemer in which unit-length molecules are joined together in head-to-tail fashion through terminally redundant sequences. During packaging of DNA, mature monomers are cut from the concatemer. The cutting is obligatorily coupled to DNA packaging. The packaging of phage DNA is under the control of a pair of noncapsid proteins, called packaging proteins, gp 18 and gp19. gp19 is an ATP-binding protein that plays multiple roles in DNA packaging. gp19 is predicted, from the sequence of its gene, to contain 586 amino acids, and has consensus sequences for an ATP binding site. To dissect structure-function relationships of gp19, mutations were introduced into the ATP binding domain and the mutant proteins were overproduced, purified and characterized. Mutant gp19 with a Gly-to-Asp mutation at amino acid 61 (gp19 G61D) was defective in DNA packaging due to an altered interaction with ATP. Gp19 G424E, with a change in another putative ATP binding domain, was active in DNA packaging but was defective in DNA cutting. A second mutation in the latter domain, gp19 K430T, and a mutation at 553 (to give gp19 H553L), within a putative Mg2+ binding domain, had only minor effects on gp19 activities.

Amino Acid Sequence↗
PubMed1991

Analysis of interactions among factors involved in the bacteriophage T3 DNA packaging reaction in a defined in vitro system.

During head assembly of phage T3, DNA is packaged into the cavity of a preformed protein shell, called the prohead, with the aid of noncapsid, packaging proteins, the products of genes 18 and 19 (gp18 and gp19). gp18 and gp19 separately form complexes with DNA and proheads, respectively. These complexes associate to form a precursor which can be converted to filled heads by the addition of ATP. Interactions among factors involved in DNA packaging were analyzed. In the presence of ATP, gp19 formed functional complexes with proheads. Formation of gp19-prohead complex showed a sigmoidal dependence on ATP concentration with a half maximal concentration of about 7.5 microM. Six molecules of gp19 bound to the prohead at a saturating amount of gp19. gp19 did not bind to proheads lacking the connector of gp8 (8- prohead). In the absence of ATP, proheads were inactivated by gp19. The gp19-prohead complexes formed in the absence of ATP contained 20-30 gp19 molecules per prohead and formed multimeric aggregates. 8- proheads did not bind gp19 and did not form such aggregates even in the absence of ATP. From these results, we conclude that 6 molecules of gp19 bind to the gp8 connector structure in the portal vertex of the prohead. The cleavage patterns of gp19 by several proteases were altered by the addition of ATP, indicating that ATP induces a conformational change in gp19, gp18 bound only to linear, duplex DNA.

Adenosine Triphosphate↗
PubMed1991

Immunohistochemical localization of tissue-type plasminogen activator in the lining wall of chronic subdural hematoma.

Capsules of chronic subdural hematoma were immunohistochemically stained with monoclonal antibody against tissue-type plasminogen activator. Endothelial cells of sinusoids and capillaries in the outer membrane showed strong immunostaining. Endothelial cells of veins and arteries in the dura mater showed moderate and weak staining. No cells other than the endothelial cells were stained. In the inner membrane, tissue-type plasminogen activator immunoreactivity was not seen. The mean concentration of tissue-type plasminogen activator in the hematoma content was higher than that in the plasma. The more the sinusoids in the outer membrane were developed, the higher the concentration of tissue-type plasminogen activator contained in the hematoma fluid. In chronic subdural hematoma, overproduction and oversecretion of tissue-type plasminogen activator from the sinusoidal and capillary endothelial cells in the outer membrane cause increased fibrinolysis, which in turn impairs hemostasis, and hemorrhage from the capillaries recurs, resulting in enlargement of the chronic subdural hematoma.

Adult↗
PubMed1991

Projection of the retinal ganglion cells to the tectum differentiated from the prosencephalon.

The alar plate of the prosencephalon differentiates into a tectum-like structure when transplanted into the mesencephalon around the 10-somite stage. Here, we report on the projection pattern of the retinal ganglion cells to the transplants. Optic nerve fibers were labeled with horseradish peroxidase (HRP) and 3H-proline, and the innervation of the optic nerve fibers to the chimeric tectum was analyzed by HRP histochemistry on whole-mounted specimens, by autoradiography and by electron microscopy on embryonic day 16. In the chimeric tectum, the transplant was distinguished from the host by difference in nuclear structure between the quail and the chick cells. It was shown that the transplant had the laminar pattern of the optic tectum when the transplant was integrated into the host mesencephalon. The whole-mount HRP histochemistry showed that the optic nerve fibers extend to the transplants. Autoradiography showed that the distribution pattern of silver grains was similar in both the host and the transplant. These results may indicate that the optic nerve fibers turn to the transplant and terminate on the transplant. Electron microscopy further confirmed that optic nerve fibers ended by making synaptic contacts with the dendrites in the transplant region of the tectum. These results indicate that the transplant with the laminar pattern of the optic tectum is a true tectum receiving input from the eye.

Animals↗
PubMed1991

The A5 antigen, a candidate for the neuronal recognition molecule, has homologies to complement components and coagulation factors.

The A5 antigen is a neuronal cell surface protein of Xenopus presumed to be involved in the neuronal recognition between the optic nerve fibers and the visual centers. Analyses of cDNA clones revealed that the A5 antigen is a class I membrane protein containing two different internal repeats in the extracellular segment. The first repeat bears homology to domain III of complement components C1r and C1s, and the second repeat is homologous to the C1 and C2 domains of coagulation factors V and VIII. The mRNA for the A5 antigen was present in retinal ganglion cells and visual center neurons. Nonneuronal cells in the peripheral and central nervous systems did not express the mRNA for the A5 antigen.

Amino Acid Sequence↗
PubMed1991

Differentiation disorders of keratinocytes in seborrheic keratosis (acanthotic type).

Since the differential disorder of keratinocytes in seborrheic keratosis remains to be elucidated, the differentiation of seborrheic keratosis (acanthotic type) was examined immunohistochemically using a lectin and two anti-keratin monoclonal antibodies. A lectin, peanut agglutinin (PNA), and anti-keratin monoclonal antibody, 34 beta B4, recognize the whole epidermis except for the basal layer in the normal epidermis. In seborrheic keratosis (acanthotic type), cells unstained with either PNA or 34 beta B4 were found throughout the entire tumor. In the upper part of the tumor, some cells appeared to undergo keratinization without expressing the differential markers recognized by PNA or 34 beta B4. Another anti-keratin monoclonal antibody, 34 beta E12, stained the tissues in the same way as in the normal epidermis. Thus it was indicated that, in seborrheic keratosis (acanthotic type), although differentiation was partially maintained, some cells might undergo maturation without expressing the differentiation markers recognized by PNA or 34 beta B4.

Aged↗
PubMed1991

Conversion of tyrosine hydroxylase to stable and inactive form by the end products.

We have reported previously that tyrosine hydroxylase in the crude extract from rat striatum exists in the inactive form showing almost no activity at the physiological pH and that the inactive form is produced by the action of the end products of the enzyme, such as dopamine. The incubation of the enzyme with the end products resulted in not only the inactivation but also a remarkable stabilization of the enzyme. Catechols possessing amino groups but no negatively charged groups on the side chains (catecholamine-type catechols) were effective at a concentration as low as 10(-7) M in both the inactivation and stabilization of the enzyme. In contrast, catechols not possessing positively or negatively charged side chains (3,4-dihydroxyphenylethyleneglycol-type catechols) were ineffective at a concentration of 10(-7) M but effective at a concentration of 10(-6) M for both the inactivation and stabilization. Catechols possessing negatively charged groups (3,4-dihydroxyphenylacetic acid-type catechols) were ineffective even at a concentration of 10(-6) M. Thus, the end products of tyrosine hydroxylase appear to serve to keep the enzyme inactive and stable. The reaction mechanism of the conversion of the enzyme from the active/labile form to the inactive/stable form by dopamine was also investigated.

Animals↗
PubMed1991

Exocytosis in pheochromocytoma cells after exposure to a high concentration of potassium.

An electron-microscopic study revealed exocytosis of electron-dense granules in rat pheochromocytoma (PC12) cells after 1-min exposure to a high concentration of potassium medium. Numerous omega profiles indicative of the exocytosis were seen in the surface membrane of the PC12 cells. Most omega profiles showed clear or did not contain the granule contents. Sometimes, the granular, flocculent or dense materials were seen within the omega profiles that were exposed directly to the extracellular medium. Moreover, noncoated or coated omega profiles were observed. Coated vesicles were also visible under the surface membrane. The present study suggests that PC12 cells retain the exocytotic release mechanism for catecholamines.

Animals↗
PubMed1991

Inhibitory effects of catechol derivatives on arachidonic acid-induced aggregation of rabbit platelets.

Pyrocatechol and other non-substituted dihydric phenols, which have strong redox power, inhibited arachidonic acid-induced aggregation of rabbit platelets at much lower concentrations than those at which these phenols inhibited stable prostaglandin endoperoxide, U46619-induced aggregation. Among non-substituted dihydric phenols, pyrocatechol was most potent. In order to clarify the physicochemical properties of the phenolic compounds which control the inhibitory potencies of dihydric phenols, we observed the inhibitory effects of 3- and 4-substituents of pyrocatechol on arachidonic acid-induced platelet aggregation. Among seven derivatives tested, the inhibitory effect of 4-C6H5-substituent was strongest and 4-COOH-substituent was weakest. Inhibitory effects of the catechol derivatives were well correlated with the quotients of their hydrophobicities and oxidation-reduction potentials. Inhibitory effects of hydroquinone and resorcinol were also on the same correlation line. These results suggest that the inhibitory effects of catechol derivatives and other dihydric phenols are controlled by two physicochemical properties: oxidation-reduction potential and hydrophobicity.

Animals↗
PubMed1991

Pharmacological properties of the new non-steroidal anti-inflammatory agent etodolac.

The anti-inflammatory, analgesic, antipyretic and ulcerogenic activities of etodolac (CAS 41340-25-4), a new nonsteroidal anti-inflammatory agent, were compared with those of indometacin and other anti-inflammatory drugs in experimental animals. Etodolac had a remarkable anti-inflammatory effect in various experimental models: ultraviolet erythema, carrageenin-induced edema and swelling of adjuvant arthritis. In these models, the effective dose of etodolac was several fold that of indometacin. Etodolac inhibited prostaglandin E2 formation in a concentration-dependent manner, and its inhibitory potency was about 1/5 of that of indometacin. Etodolac also caused marked inhibition of granuloma formation and leucocyte functions such as chemotaxis, lysosomal enzyme release and active oxygen generation. These effects of etodolac were observed at similar doses of indometacin. Etodolac suppressed inflammatory pain but not non-inflammatory pain, and had an antipyretic effect but did not lower normal rectal temperature. Etodolac had no effect on delayed hypersensitivity reactions and was much less ulcerogenic than indometacin. These results indicate that etodolac is a low ulcerogenic anti-inflammatory agent with suppressing activities on leucocyte functions to the same extent as indometacin and prostaglandin biosynthesis.

Animals↗
PubMed1991

Differentiation of the basal cell epithelioma-like changes overlying dermatofibroma.

Epidermis overlying dermatofibroma rarely displays basal cell epithelioma-like changes (BCE-like changes). Based on the histopathological findings, whether BCE-like changes are induced by dermal lesion or adnexal regression secondary to the solid fibrotic growth remains to be explored. From the standpoint of differentiation, we examined the BCE-like changes overlying dermatofibroma, normal epidermis, and hair follicles. PNA and two kinds of anti-keratin monoclonal antibodies were used to detect markers for epidermal differentiation. When PNA and anti-keratin monoclonal antibody (34betaB4) were used, no difference was observed in the staining patterns among BCE-like changes, hair follicles or normal basal cells. With the other anti-keratin antibody (34betaE12), BCE-like changes and normal basal cells were recognized, though the hair matrix was not. Thus the results obtained indicate that normal basal cells show the most similar differentiation to BCE-like changes.

Antibodies, Monoclonal↗
PubMed1991

Mechanism of anti-inflammatory action of etodolac.

The effect of etodolac (CAS 41340-25-4) on the inflammatory reactions induced by histamine and bradykinin was compared with that of indomethacin and other nonsteroidal anti-inflammatory drugs. Etodolac (50 mg/kg p.o.), indomethacin (20 mg/kg p.o.), diclofenac Na (20 mg/kg p.o.) and acetylsalicylic acid (200 mg/kg p.o.) had no effect on the increase of vascular permeability induced by histamine or bradykinin and on passive cutaneous anaphylaxis in rats. Etodolac (5, 10 and 20 mg/kg p.o.) suppressed concanavalin A-induced paw edema in rats. Etodolac (10 mg/kg p.o.) and bromelain (10 mg/kg i.v.) significantly suppressed the heat-induced elevation of bradykinin in perfusates of rat paws, but indomethacin (20 mg/kg p.o.) and diclofenac Na (20 mg/kg p.o.) did not. Etodolac inhibited bradykinin-forming enzyme activity in a concentration-dependent manner (IC50 = 1.5 x 10[-4) mol/l). These results suggest that etodolac is a unique nonsteroidal anti-inflammatory drug which can inhibit bradykinin formation, unlike indomethacin or diclofenac Na.

Animals↗
PubMed1991

Xeroderma pigmentosum patients belonging to complementation group F and efficient liquid-holding recovery of ultraviolet damage.

A 73-year-old woman with xeroderma pigmentosum (XP), XP107TO, was assigned to complementation group F. The fibroblast of this patient showed a reduced level (19%) of unscheduled DNA synthesis (UDS) compared with normal cells. XP107TO cells were 2.3 times more hypersensitive to ultraviolet C (UVC) than normal cells and in the same range of other XPF cells. A clinical case report of 2 patients belonging to XP group F is also described; together with these clinical findings, the characteristics of XP group F are discussed. These patients manifested mild clinical symptoms, developing skin cancer in later age, although acute sun sensitivity was observed in early age (usually a few months after birth). Fibroblasts derived from these patients showed a substantially reduced level of UDS, considering its mild clinical features. To analyze the discrepancy of low UDS level and late onset of skin cancer in XPF cells, we examined the UV sensitivity under density-inhibited condition using XPF cells. XP cells belonging to complementation group F showed marked enhancement of UV survival when they were held in a density-inhibited condition for 1-4 d after UV irradiation. The enhancement was also observed in normal and XP group A cells, but the recovery in these cell lines was less than that in XP group F cells. XP group F cells have been shown to possess slow and long-lasting excision repair capacity and this type of repair might be stimulated by holding through time of the repair process within one cell cycle.

Adult↗
PubMed1991

[Brain tumors in Yamaguchi Prefecture--incidence through 4 years].

The incidence of brain tumors was studied in Yamaguchi prefecture of about 1,600,000 population. All of the brain tumor patients admitted to the neurosurgical hospitals in Yamaguchi prefecture were registered. Cases of osteoma, lipoma, scalp tumor and spinal tumor were excluded. From 1986 through 1989, 726 cases were registered. 135 recurrent cases were included. Therefore first-diagnosed primary brain tumors were selected to calculate the true incidence. The number of cases of primary brain tumor was 478 and showed female preponderance (male/female: 207/271). The incidence of primary brain tumor was 7.5/100,000/year (male/female: 6.8/8. 1). No difference was present between the incidence in cities and that in rural districts. Percentages of representative tumors were 28.2% for glioma, 32.8% for meningioma, 13.0% for pituitary adenoma and 10.7% for neurinoma. Age-adjusted incidence was 2.1/100,000/year for glioma and 2.1/100,000/year for meningioma. The incidence of glioma was lower and that of meningioma was higher in Yamaguchi prefecture than those in other reports. Compared with the Brain Tumor Registry of Japan (1969-1983), the percentage of meningioma cases was large in Yamaguchi prefecture. This difference owed partly to the increased number of population over age of 40's in Yamaguchi prefecture. The peak of age distribution was present in age of 50's in Yamaguchi prefecture and in age of 30's and 40's in Brain Tumor Registry of Japan. The peak of age distribution shifted to older ages in Yamaguchi and the difference was conspicuous in age of 60's. This peak consisted of mainly cases of meningioma and partly those of glioma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1991

[A case of intraventricular cyst associated with normal pressure hydrocephalic condition].

A case of intraventricular cyst associated with normal pressure hydrocephalic condition (NPHC) is reported. A 72 year-old female, with 2-year-history of slowly progressing dementia and gait disturbance, was admitted to our hospital on September 19, 1989. On admission, she had mild dementia, unsteadiness of gait, and at times urinary incontinence. Cerebrospinal fluid (CSF) pressure was found to be 90mmH2O by lumbar tap. Plain computed tomographic (CT) scan and T1-weighted magnetic resonance image (MRI) showed asymmetrical enlargement of the trigon and posterior horn of the right lateral ventricle. CT cisternography showed a cyst in the trigon and in the posterior horn of the right lateral ventricle. T1-weighted MRI with Gd-DTPA demonstrated no enhancement of the cyst wall, and there was superior and posteromedial displacement of the choroid plexus at the trigon of the right lateral ventricle. The patient was diagnosed as having an intraventricular cyst in the right trigon with NPHC. Ventriculo-peritoneal shunt and partial removal of the cyst were performed. Histological examination of the cyst wall revealed collagenous strands and no epithelial cells. Developmental intracranial cysts, especially arachnoid or ependymal cysts, occasionally lack an epithelial layer, so their histological diagnosis is difficult. This case was considered to be an arachnoid cyst because there was adhesion between the cyst and the choroid plexus in the right trigon, and superior, posteromedial displacement of the choroid plexus, which indicated extension of the cyst from the extracerebral to the intracerebral region. NPHC was considered to be due to disturbance of CSF circulation caused by gradual expansion of the cyst.

Aged↗
PubMed1990

Involvement of activator protein in the activation of tryptophan hydroxylase by cAMP-dependent protein kinase.

The tryptophan hydroxylase activity of the crude extract from rat brain stem was stimulated approximately 2-fold by incubation with cAMP analogues under protein phosphorylating conditions. The cAMP-dependent activation process of the enzyme needed not only cAMP-dependent protein kinase but also activator protein. The kinetic properties of the enzyme activated by cAMP-dependent protein kinase were very similar to those of the enzyme activated by calmodulin-dependent protein kinase II.

Animals↗