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Biomedical subjects

M Fujii

Publications and source records attributed to M Fujii.

At least 469 records · Page 26Linked to original sources
PubMed1994

Two distinct regions form a functional activation domain of the HTLV-1 trans-activator Tax1.

Tax1 of human T-cell leukemia virus type 1 (HTLV-1) is an enigmatic viral transactivator that regulates expression of the viral gene and also several cellular genes normally controlled by various mitogenic signals. However, previous studies have failed to define the functional domains of Tax1 for enhancer specificities and for transcriptional activation (95% of the protein portion was indispensable for the activation function). This complexity has hampered understanding of the molecular basis of Tax1 action. In this study, we analysed the activation function of a Tax1 fused to the heterologous DNA-binding domain of the yeast transcription factor GAL4 and dissected the domain required for the activation function by using derivatives of a Tax1 mutant with an insertion between amino acids (a.a.) 170 and 171. Analysis of the derivatives of the mutant fusion protein having various partial overlaps encompassing the interrupted site suggested that two contiguous stretches, AD-I (2-255 a.a.) and AD-II (227-337 a.a.), should be both intact for the activation function of Tax1 and that they form a functional activation domain.

3T3 Cells↗
PubMed1993

Long distance transplant-to-host axon elongation without target deafferentation.

To confirm the entire course of the long distance transplant-to-host axon elongation, the Thy-1 mouse allelic system was used for marking the olfactory bulb (OB) transplant. Axons from OB transplanted into the lateral ventricle and adjacent areas extended for a long distance, through three routes, to the frontal cortical surface, to the olfactory tubercle, the primary olfactory cortex and OB. Because of the OB graft insertion from the dorsal aspect through the neocortex, the host olfactory system remained unaffected. These results demonstrated that the transplanted OB could express its intrinsic ability of the long distance axon elongation without target deafferentation and even if the OB is inserted in the rather mature host.

Animals↗
PubMed1993

Specific modification of structure and property of myoglobin by the formation of tetrazolylhistidine 64(E7). Reaction of the modified myoglobin with molecular oxygen.

Tetrazole-myoglobin (Tet-Mb), a site selectively modified myoglobin with tetrazole anion (-CN4-) covalently attached to the imidazole N epsilon of the distal histidine 64(E7) (see Fig. 1; Kamiya, N., Shiro, Y., Iwata, T., Iizuka, T., and Iwasaki, H. (1991) J. Am. Chem. Soc. 113, 1826-1829), exhibited unique properties in the reduction from ferric to ferrous states and in the reaction of its deoxy form with O2. The redox potential of Tet-Mb is obtained to be -193 mV, which is much lower than that of unmodified (native) myoglobin (50 mV), possibly due to the electrostatic interaction between the heme iron and the tetrazole group. The ferrous deoxy form of Tet-Mb was rapidly oxidized to its ferric form in the reaction with O2 at room temperature through an intermediary formation of its oxy form and with the generation of O2-. The oxy form of Tet-Mb can be detected by the optical spectral measurement at -12 degrees C, the rapid scan measurement at room temperature, and the electron spin resonance measurement of its cobalt-substituted derivative (Tet-Mb(Co2+)) at 77 K. In the kinetic measurement of the O2 binding reaction to Tet-Mb, its association and dissociation rate constants in the bimolecular reaction were 6.1 x 10(7) M-1 s-1 and 2200 s-1, respectively, showing that the tetrazole modification of His-64 extremely accelerates its association and dissociation rates. Taken together with the extremely fast autoxidation rate (53 h-1) obtained, these kinetic results suggested that the channel of O2 from the solvent region to the protein interior is open enough to pass the external ligand. The structure is discussed in relation to those of some genetic mutants. Taking these properties, we demonstrated that Tet-Mb can catalyze O2 consumption to generate O2-, coupled with the NADH-supported enzymatic reduction system of cytochrome P-450cam under an aerobic condition.

Amino Acid Sequence↗
PubMed1993

The porphyrin-iron hybrid hemoglobins. Absence of the Fe-His bonds in one type of subunits favors a deoxy-like structure with low oxygen affinity.

Protoporphyrin-protoheme hybrid hemoglobins (Hb), in which the protohemes (Fe) in either the alpha- or beta-subunits were substituted with protoporphyrins IX (PP) alpha(PP)2 beta(Fe)2 and alpha(Fe)2 beta(PP)2 have been prepared. The structural and functional properties of these hybrid Hbs were investigated by measuring oxygen equilibrium curves and proton nuclear magnetic resonance spectra. The equilibrium constants of the first ligand, K1, observed for alpha(PP)2 beta(Fe)2 were much smaller than K1 values of HbA. The effects of pH and inositol hexaphosphate on K1 were substantially diminished. On the other hand, K1 values of alpha(Fe)2 beta(PP)2 were similar to those of HbA, including the pH and inositol hexaphosphate effects. The deoxy forms of alpha(PP)2 beta(Fe)2 and alpha(Fe)2 beta(PP)2 showed exchangeable proton resonances at 11 and 14 parts/million arising from the hydrogen bonds at the alpha 1 beta 2 contact in a deoxy-like structure. In the liganded form, these signals were dependent upon solution conditions. As K1 became larger, the reduction in the intensity of these signals was observed for both liganded forms. The resonance position of E11 Val originating from the beta subunits of alpha(PP)2 beta(Fe-CO)2 also varied in accordance with K1. We compare properties of PP-Fe hybrids with those of Co-Fe and Ni-Fe hybrids and conclude that the first oxygen binding to the beta heme may be linked to the metal-proximal His interaction in the alpha subunits. However, the first oxygen binding to the alpha heme is linked minimally to the metal-proximal His interaction in the beta subunits but may be correlated instead to the position of E11 Val relative to the porphyrin plane in the beta subunits.

Hemoglobins↗
PubMed1993

Thalamic neuronal hyperactivity following transection of the spinothalamic tract in the cat: involvement of N-methyl-D-aspartate receptor.

Single neuron activities responding to peripheral stimuli with short latencies were recorded within the thalamic nucleus ventralis posterolateralis (VPL) after transection of the spinothalamic tract (STT) in the cat under alpha-chloralose anesthesia. The VPL neurons showed spontaneous and evoked hyperactivity after STT transection, which was revealed at 1-2 weeks. The spontaneous hyperactivity further progressed until 3-4 weeks. These hyperactivities were observed in core-area neurons as well as neurons found in the shell area, suggesting that some, if not many, of the N-methyl-D-aspartate (NMDA) receptor antagonist (MK-801, 4-16 mg; i.v.) attenuated both the spontaneous and evoked hyperactivity observed after STT transection. No such effects were demonstrated in sham-operated animals. These findings suggest that VPL neurons become hyperactive after STT transection through recruitment of NMDA receptors. The hyperactivity of VPL neurons may represent an important background process in the production of deafferentation pain induced by lesions involving the STT.

Amino Acids↗
PubMed1993

Dynamic changes in cytochrome oxidase activity in the rat somatosensory cortex following thalamocortical deafferentation.

The changes in cytochrome oxidase (CYO) activity in the primary somatosensory cortex (SI) induced by unilateral lesions restricted to the posterior ventrobasal region of the thalamus were investigated by histochemical techniques and photometric semi-quantitation in the rat. The CYO activity decreased rapidly and dramatically in layer IV of the lesioned side, reaching its lowest level within 2 weeks, and remained depressed at 8 weeks post-lesion. Segmentations normally seen in layer IV corresponding to barrels remained absent. While less marked decreases were also noted in other layers, obvious recovery was subsequently observed, attaining levels comparable to those on the intact size at 6 or 8 weeks post-lesion. The persistent decrease in layer IV appears to reflect a reduced thalamocortical activation of the dendritic profiles and neuronal perikarya. The recovery in other layers may represent an increase in the resting level of the initially depressed neuronal activity near to the original levels. The persistent reduction of function in the inhibitory surround, which is normally activated by thalamocortical input, may contribute to the increase in CYO activity.

Afferent Pathways↗
PubMed1993

Human T-cell leukemia virus type 1 Tax activates transcription of the human fra-1 gene through multiple cis elements responsive to transmembrane signals.

We have shown that Tax1 of human T-cell leukemia virus type 1 stimulates the expression of several cellular immediate-early genes (M. Fujii, T. Niki, T. Mori, T. Matsuda, M. Matsui, N. Nomura, and M. Seiki, Oncogene 6:1023-1029, 1991). In this study, the 5'-flanking region of the human fra-1 gene, which is a Tax1-inducible fos-related gene, was isolated and Tax1 or serum-responsive cis elements were analyzed to obtain further insight into the mechanism of Tax1 action. The 62-bp sequence starting 46 nucleotides upstream from the translation initiation site showed 71% homology with the sequence surrounding the TATA box of the c-fos promoter. Regulatory motifs identified in the c-fos promoter, such as an Ets-binding site, E boxes, a CArG box, c-fos AP-1 sites, and two retinoblastoma control elements, were also found upstream of the c-fos homology region. A 502-bp fragment containing these motifs mediated transcriptional activation by Tax1 or by serum in a transient transfection assay. Three independent Tax1-responsive regions (TRRs) were identified, and mutations in each revealed that one of the retinoblastoma control elements in TRR1 and the c-fos AP-1 sites in TRR2 and TRR3 were essential for the activation. Although TRR2 contains a CArG box-like sequence, it was a weak binding site for p67SRF, if it bound at all, and was not required for activation. All three TRRs could also mediate the signals stimulated by serum. Thus, Tax1 appears to activate fra-1 gene expression by means of a part of the cellular machinery similar to that which mediates growth signals.

Base Sequence↗
PubMed1993

Transient rise in serum interleukin-8 concentration during acute myocardial infarction.

OBJECTIVE: To determine whether interleukin-8 (IL-8, a potent activator of neutrophils) is involved in tissue injury during ischaemia and reperfusion in patients with acute myocardial infarction. SETTING: Teaching hospital. SUBJECTS: Five consecutive patients with acute Q-wave myocardial infarction, two patients with stable angina who underwent elective percutaneous transluminal coronary angioplasty, and 10 normal controls. MAIN OUTCOME MEASURE: Serum IL-8 concentration measured by enzyme linked immunosorbent assay (ELISA) over time (every four, eight or 12 hours for 36-72 hours). RESULTS: All five patients with acute myocardial infarction had a transient but significant rise in serum IL-8 concentration (13-1100 ng/l) within 22 hours after the onset of symptoms, whereas IL-8 was not detected in any of the samples from patients with angina pectoris or normal controls. One patient who died of pump failure and two patients who had mild congestive heart failure showed the highest values (1100, 920, and 190 ng/l respectively). CONCLUSIONS: Serum IL-8 concentration showed a transient rise during the very early phase of acute myocardial infarction. In combination with several recent lines of evidence indicating the importance of injurious activities of neutrophils as a cause of tissue damage in acute myocardial infarction and the potent stimulation of neutrophils by IL-8, these results strongly suggest that IL-8 is important in the development of myocardial injury in acute myocardial infarction.

Adult↗
PubMed1993

Differential effects of proteinase inhibitor camostat on exocrine pancreas in fed and fasted rats.

Effects of an oral dose of the synthetic trypsin inhibitor camostat on pancreatic exocrine function were examined in rats that were either fasted from 12 h before feeding camostat to the end of experiments or fed ad libitum. Camostat (100 mg/kg body wt) caused significant increases in plasma cholecystokinin bioactivity (peak 13.4 +/- 2.0 pM at 30 min for fasted rats vs. 16.6 +/- 1.7 pM at 2 h for fed rats; not significant) and pancreatic exocrine secretion. In fed rats, but not in fasted rats, significant increases in pancreatic exocrine secretion were observed again at 12 h after a single oral dose of camostat (juice flow 10.3 +/- 0.4 microliters/20 min in fasted rats vs. 175.5 +/- 17.8 microliters/20 min in fed rats; P < 0.001), although pancreatic juice flow in fed and fasted control rats was nearly the same. When the pancreata from camostat-pretreated rats were isolated and perfused, the early effects of camostat on pancreatic exocrine secretion were abolished, whereas the late effects (12 h postfeeding) in fed rats were still observed (juice flow 33.7 +/- 3.4 microliters/20 min vs. control 2.8 +/- 0.4 microliters/20 min; P < 0.001). Thus, in addition to humoral and neural factors, persistent functional changes might have occurred in the pancreas of the fed camostat-pretreated rats. These present results indicate that oral camostat induces two different effects, immediate and delayed, on pancreatic exocrine secretory function. Camostat exerts its immediate effects in both fed and fasted rats, whereas delayed effects were induced only in fed rats.

Administration, Oral↗
PubMed1993

Isolation and characterization of angiotensin I-converting enzyme inhibitory peptides derived from bonito bowels.

Four angiotensin I-converting enzyme (EC 3.4.15.1) (ACE) inhibitory peptides C105, C107, C111, and C112 were isolated from bonito bowels. C111 was obtained from liver, while the others were from intestine. Their amino acids were sequenced as Ser-Val-Ala-Lys-Leu-Glu-Lys for C105, Ala-Leu-Pro-His-Ala for C107, Gly-Val-Tyr-Pro-His-Lys for C111, and Ile-Arg-Pro-Val-Gln for C112. Their ACE inhibition activities were measured for synthetic peptides. The IC50 of these peptides were estimated to be 82, 79, 1.6, and 1.4 microM, respectively. Carboxyl-terminal amino acid(s) were considered to be essential for their expression of ACE inhibition for C105, C107, and C111, while the amino terminal tripeptide Ile-Arg-Pro of C112 was presumed to inhibit ACE after the removal of a dipeptide from C112 with ACE digestion. Presumed original proteins of these peptides are discussed.

Amino Acid Sequence↗
PubMed1993

Antihypertensive effects of peptides in autolysate of bonito bowels on spontaneously hypertensive rats.

An autolysate of bonito bowels was treated with ultrafiltration, loose RO concentration, ion-exchange chromatography, and reverse phase chromatography to increase its potency to inhibit angiotensin I-converting enzyme (ACE) activity by 16-fold. Oral administration of the partially purified autolysate decreased the systolic blood pressure of spontaneously hypertensive rats (SHR) in a dose-dependent manner at the doses of 1 g peptides/kg or higher. The relationship between the antihypertensive activity (in vivo) of the partially purified preparation and its ACE inhibitory activity (in vitro) in comparison with previously reported ACE inhibitory peptides is discussed.

Amino Acid Sequence↗
PubMed1993

Angiotensin I-converting enzyme inhibitory peptides derived from bonito bowels autolysate.

Six angiotensin I-converting enzyme inhibitory peptides were isolated from a bonito bowels autolysate. Their amino acids were sequenced as Tyr-Arg-Pro-Tyr, Gly-His-Phe, Val-Arg-Pro, Ile-Lys-Pro, Leu-Arg-Pro, and Ile-Arg-Pro. Peptides having corresponding amino acid sequences were synthesized by a solid-phase method and their inhibition of the activity measured. IC50 of these peptides were estimated to be 320, 1100, 2.2, 2.5, 1.0, and 1.8 microM, respectively. The role of carboxyl terminal proline residues on the inhibition is discussed.

Amino Acid Sequence↗
PubMed1993

Platelet abnormalities in a dog suffering from gangrenous mastitis by Staphylococcus aureus infection.

Severe gangrenous mastitis due to Staphylococcus aureus infection was diagnosed in a 7 year-old intact female beagle which was presented with swelling of mammary glands after dystocia. Leukocytosis (25,200-48,600/microliters), decreased platelets (107,000-179,000/microliters), and abnormal platelet pattern continued during the critical condition. Consistent with platelet pattern, large platelets were observed in the blood smear. The number of leukocytes and platelets rapidly returned to normal during treatment, and the platelet pattern was also restored. The number and pattern of platelet may provide a clue for the evaluation of the clinical condition and/or severity of the lesions in the dog with mastitis.

Animals↗
PubMed1993

Prognostic significance of proliferating cell nuclear antigen (PCNA) expression in non-small cell lung cancer.

Formalin-fixed, paraffin-embedded tissue sections of resected tumors from 90 patients were immunohistochemically studied to assess the prognostic value of proliferating cell nuclear antigen (PCNA) expression in non-small cell lung cancer. The individual tumors were classified into groups of high, moderate or low proliferative grade, and 38 (42.2%) patients had a high grade of proliferation. No statistically significant correlations were observed between PCNA grade and TNM status, pathological stage, resectability, histological type, degree of histological differentiation. Only vascular invasion significantly correlated with proliferative grade (p < 0.05). Survival analysis showed that patients with low proliferative grade tumors survived significantly longer (a 5-year survival rate of 83.3%) than those with high proliferative grade tumors (39.4%, p < 0.005). Cox's multivariate analysis revealed that PCNA grade was a significant prognostic determinant of survival. These results suggest that PCNA expression provides an independent prognostic variable for patients with non-small cell lung cancer and that it may be useful to consider this factor in treatment planning.

Aged↗
PubMed1993

Mortality and morbidity in two-year disease-free survivors of small cell lung cancer after treatment with combination chemotherapy with or without irradiation.

We evaluated the long-term outcome of 148 patients with small cell lung cancer (SCLC) who had been entered into clinical trials of chemotherapy with or without thoracic and prophylactic cranial irradiation (PCI) between 1981 and 1987. Eighteen patients (12%) survived for 2 or more years. With a minimum follow-up of 4.5 years, 10 of the 18 patients who remained disease-free at 2 years are currently alive and free of SCLC. Seven of these 10 patients currently function as they did before diagnosis. However, three suffer from central nervous system changes of varying degrees in severity which appeared 2-3 years after PCI. Eight of the 18 patients who were disease-free at 2 years have died. Two died of isolated relapse in the brain at 3.6 and 4.2 years after initiation of chemotherapy. Five died of other malignancies while continuing their complete response to SCLC; two of non-small cell lung cancer, two of acute myelogenous leukemia, and one of hepatocellular carcinoma. Another patient died of an unrelated disease without any evidence of SCLC. A small but substantial proportion of patients who underwent intensive treatment will achieve long-term survival; however, these patients remain at higher risk for second cancers and late toxicities. Therefore, attention must be directed to defining the safest way to employ such treatment in the management of SCLC.

Adult↗
PubMed1993

Long-term results of combination chemotherapy with or without irradiation in small cell lung cancer: a 5- to 11-year follow-up.

Between April 1981 and December 1987, 148 patients with newly diagnosed small cell lung cancer (SCLC) were treated using combination chemotherapy with or without thoracic irradiation and prophylactic cranial irradiation (PCI) in a series of cooperative therapeutic trials. With a minimum follow-up of 4.7 years, 13 (9%) patients survived and were free of SCLC. These included 11 (15%) of 76 patients with limited disease and two (3%) of 72 patients with extensive disease. Three died without any evidence of SCLC (one each from second leukemia, non-small cell lung cancer, and unrelated disease). The remaining 10 (7%) patients are currently alive and free of SCLC beyond 4.7 years. Since late relapse beyond 5 years is a very rare event, these patients may have been cured. However, late toxicity of PCI must be kept in mind. Three among the 10 patients have suffered from neuropsychologic symptoms of varying degrees in severity. Although the long-term survival rate is a benchmark in the treatment of SCLC, modifications of therapy that may potentially avoid such toxicities should be considered hereafter.

Aged↗