Search PubMed⌕ Search

Biomedical subjects

M Higuchi

Publications and source records attributed to M Higuchi.

At least 253 records · Page 14Linked to original sources
PubMed1991

[A case of Osler-Weber-Rendu disease with brain abscess; the mechanism of the formation of brain abscess and its treatment in Osler-Weber-Rendu disease].

A 54 year-old man, who had a hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease; O-W-R) accompanied by pulmonary arteriovenous fistulas (PAVFs) and congestive heart failure, developed seizure, right hemiparesis and dysphasia. A brain CT scan revealed a cystic lesion with perifocal edema in left frontoparietal lobe. A contrast enhanced CT scan showed a ring-like enhancement. Dynamic CT scans disclosed that the ring in the cortical side was enhanced more thickly than that in the ventricular side. Considering the severity of the cardio-pulmonary condition, and the deep location of the abscess, we performed an echo-guided aspiration and drainage of the abscess under local anesthesia. No bacteria were demonstrated in the culture of the contents of the abscess. After the surgery, the right hemiparesis and dysphasia were much improved and a CT scan showed the marked reduction of the abscess. However, around eight days after the surgery, the patient showed severe pleural effusion due to progressive heart failure and died on the 11th postoperative day. Autopsy disclosed a shrunken brain abscess, multiple cerebral infarction, multiple PAVFs and severe constrictive pericarditis which was regarded as the cause of death in the patient. In this report, we presented the therapeutic advantage of echo-guided surgery for the treatment of brain abscess in a high-risk patient. We also discussed the mechanism of the formation of brain abscess in patients of O-W-R disease by reviewing published cases.

Arteriovenous Fistula↗
PubMed1991

[Two cases of TSH-secreting pituitary adenoma; endocrinological, diagnostic and therapeutic approach to the disease].

Two cases of TSH-secreting pituitary adenoma were reported. Endocrinological and immunohistochemical features of these cases were described and problems in diagnosis and treatment of the rare disease are discussed. [case 1] A 28 year-old woman suffered from hyperthyroidism with a relatively high value of serum TSH (T3; 350 ng/dl, T4; 10.0 micrograms/dl, TSH; 24.5 microU/ml). She was treated with antithyroid drug and then underwent subtotal thyroidectomy. Although the levels of serum T3 and T4 were lowered to within normal range, the level of serum TSH still remained high. One month later, she developed frontal headache, amenorrhea and bitemporal hemianopsia. A CT scan showed an enhanced mass in the sellar and suprasellar region. Preoperative endocrinological studies showed elevated values of TSH (47 microU/ml) and its alpha-subunit (9.0 ng/ml). The levels of both T3 (190 ng/dl) and T4 (10.0 micrograms/dl) were near the upper normal limit. Serum TSH was suppressed by administration of exogenous T3, but did not respond to exogenous TRH, l-Dopa nor bromocriptine. Under the diagnosis of TSH-secreting pituitary adenoma, the patient was operated on by craniotomy and received local radiation therapy (50 Gy). In 1990, 12 years after the treatment, she is well and endocrinologically normal. Immunohistochemical study revealed that most tumor cells were positive for TSH. [case 2] A 28 year-old woman visited our hospital for examination of hyperthyroidism. Serum level of TSH was detectable (4.5 microU/ml). A CT scan performed at that time disclosed no pituitary tumor. Thyroid function was normalized by antithyroid drug, but the level of TSH was still high and progressively increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1991

[Marked growth of arteriovenous malformation 19 years after resection: a case report].

We report a case of arteriovenous malformation (AVM) which recurred as a giant AVM 19 years after resection. At the age of 23, the patient underwent craniotomy for a small AVM with surrounding old hematoma in the right parietal lobe. The AVM was judged to have been removed completely on postoperative angiography, while abnormal small vessels were noted retrospectively. He did well until 19 years later when he had seizures. Repeated angiography showed huge recurrent AVM at the operative site. Considering the risk involved in surgery, he was discharged from the hospital with anticonvulsants. Recurrence of AVM after removal is rare, but patients with AVM surgery should be followed up with CT and angiography for a long period of time.

Adult↗
PubMed1990

Physicochemical and biological characterization of asialoerythropoietin. Suppressive effects of sialic acid in the expression of biological activity of human erythropoietin in vitro.

Various partially or fully desialylated human erythropoietins were obtained by neuraminidase digestion of the hormone, without non-specific proteolysis and degradation of carbohydrates. Asialoerythropoietin showed a specific activity of 220-IU/mg protein in vivo, although that of the intact erythropoietin was 2.2 x 10(5) IU/mg. A linear relationship was found between the logarithm of the specific activity in vivo and the number of sialic acids. The asialoerythropoietin showed a four-times-higher specific activity in vitro compared with intact erythropoietin using mouse bone marrow cells. It also showed an approximately six-times-higher specific activity in a colony-forming assay for the erythroid colony-forming unit and the erythroid burst-forming unit. Partially or fully de-N-glycosylated erythropoietin derivatives also showed lower in vivo activity but higher in vitro activity than the intact erythropoietin, dependent on the number of sialic acids. To clarify the reason for the enhanced biological activity of asialoerythropoietin in vitro, the binding of intact 125I-erythropoietin or 125I-asialoerythropoietin to cells containing specific receptors for the hormone was analyzed. 125I-asialoerythropoietin bound to spleen cells from anemic mice approximately five times faster than did intact 125I-erythropoietin. The amount of 125I-asialoerythropoietin internalized by target cells, measured in the absence of NaN3, was four times higher than that of intact erythropoietin. These results demonstrate that asialoerythropoietin binds to its receptor faster than the intact form. This may be the main reason for the increased activity of asialoerythropoietin in vitro.

Animals↗
PubMed1990

Cytolytic mechanisms of activated macrophages. Tumor necrosis factor and L-arginine-dependent mechanisms act synergistically as the major cytolytic mechanisms of activated macrophages.

We examined the cytolytic mechanisms of activated macrophages by using proteose peptone- or thioglycollate broth-induced mouse peritoneal macrophages or mouse macrophage hybridomas as effector cells, L.P3 cells, a clone of L929 cells, and P815 cells as target cells, and IFN-gamma and LPS as activators. It was determined that TNF is the main cytolytic molecule against L.P3 cells from the following results: 1) activated macrophages can produce TNF; 2) TNF shows cytotoxic activity against L.P3 cells; 3) the addition of anti-TNF antibody inhibited most of the cytolytic activity of activated macrophages against L.P3 cells. On the other hand, it was concluded that the main cytolytic mechanism against P815 cells is the production of NO2-/NO3- from L-arginine, from the following results: 1) activated macrophages can produce NO2-; 2) NaNO2 shows high cytotoxic activity against P815 cells; 3) the depletion of L-arginine from the medium inhibited most of the cytolytic activity of activated macrophages against P815 cells and NO2- production by activated macrophages. In this study, however, cytostatic effects of L-arginine-dependent effector mechanism were not studied. Thus, these results show that activated macrophages can express at least two cytolytic mechanisms independently, namely, the one that appears to be mediated by the L-arginine-dependent effector mechanism and the second that appears to be mediated directly by TNF. Furthermore, it was demonstrated that TNF and L-arginine-dependent NO2- production act synergistically as killing mechanisms of activated macrophages. These mechanisms can explain the cytolytic activity of activated macrophages against a variety of target cells.

Animals↗
PubMed1990

[The clinical significance of antibody against oncofetal antigen-I in patients with gynecologic tumors].

Oncofetal antigen-I (OFA-I) is a membrane antigen of human cancer cells that cross-reacts with fetal brain tissues. OFA-I has been shown to be immunogenic in man by its ability to provoke humoral antibody in cancer patients which has tumoricidal potential with in vitro and in vivo experimental systems. This study evaluated the antibody profile against this antigen in relation to the course of disease. Twenty seven out of 39 patients with gynecologic tumors had persistently stable antibody levels and antibody titer in six of them increased by more than 4-fold. These patients did not show either recurrence or death, but had a good prognosis. In twelve patients, antibody levels dropped by more than 4-fold and was followed by clinical recurrence and death. These studies show that persistently stable antibody titers are predictive of non-recurrence, and decreasing titers predictive of recurrence.

Antibodies, Neoplasm↗
PubMed1990

Characterization of a thrombin cleavage site mutation (Arg 1689 to Cys) in the factor VIII gene of two unrelated patients with cross-reacting material-positive hemophilia A.

The molecular defect responsible for moderate and severe hemophilia A has been identified for two unrelated patients with the CRM-positive form of this disorder (factor VIII activity of 0.02 and 0.05 U/mL with factor VIII antigen of 0.87 and 2.20 U/mL). In both cases, the immunopurified dysfunctional factor VIII protein is abnormal, in that the 80 Kd light chain is not cleaved by thrombin at arginine-1689. The basis for this failure was identified by polymerase chain reaction amplification of exon 14 of the variant factor VIII genes and direct sequencing of the amplified products. In both cases, a single base substitution (C to T) was identified that produces an arginine to cysteine substitution at amino acid residue 1689. These data identify the molecular defects of the two identical factor VIII variant proteins. The dysfunctional factor VIII has been designated "Factor VIII-East Hartford," the residence of the patient in whom the defect was first identified.

Arginine↗
PubMed1990

Alterations in membrane fluidity during keratinocyte differentiation measured by fluorescence polarization.

The epidermis shows a distinctive pattern of differentiation wherein keratinocytes proliferate in the basal cell layer and mature into spinous and granular cells. Using a discontinuous density-gradient centrifugation method, guinea-pig keratinocytes were separated into high (HDF), intermediate (IDF), and low (LDF) density fractions. Morphological and flow cytometrical observations demonstrated that HDF, IDF, and LDF were basal, spinous, and granular cell-rich fractions, respectively. Membrane fluidity of the fractionated keratinocytes was measured by diphenylhexatriene fluorescence polarization. Polarization (p)-value of keratinocytes was negatively correlated with temperature. At each temperature, HDF cells showed a lower p-value than IDF or HDF cells except at 40 degrees C. Since a low p-value indicates a high degree of Brownian motion, membrane fluidity is higher in basal cells and lower in spinous and granular cells. Our results indicate that membrane fluidity of guinea-pig keratinocytes decreases during their maturation.

Animals↗
PubMed1990

Effect of purified recombinant human erythropoietin on anemia in rats with experimental renal failure induced by five-sixth nephrectomy.

Recombinant human erythropoietin (rHuEPO) was purified from the conditioned media of Chinese hamster ovary cells with a transfected human erythropoietin gene. We investigated the effects of the rHuEPO in rats with renal anemia induced by partial nephrectomy. Five-sixth nephrectomy resulted in renal failure with anemia. Twenty-five days after the operation plasma urea nitrogen was increased about 2.5 times, and the red blood cell count, hematocrit, and hemoglobin concentration fell to 85% of normal. The reticulocyte count and plasma erythropoietin level did not change such as they do in patients with anemia due to chronic renal failure. Both total red blood cell volume and the plasma iron turnover rate were depressed in five-sixth nephrectomized rats compared with normal rats. The five-sixth nephrectomized rats were injected with rHuEPO (60 IU/kg) intravenously every second day for a total of six injections. After three injections of rHuEPO, circulation volume of total red blood cells was increased from 9.9 ml to 14.6 ml, and the plasma iron turnover rate was increased from 1.03 mg/kg/day to 2.12 mg/kg/day, and the reticulocyte count was also increased. After six injections, a marked increase of the red blood cell count, hematocrit, and hemoglobin concentration were observed. Plasma urea nitrogen and the creatinine levels as indications for renal function did not change after rHuEPO administration in both normal and five-sixth nephrectomized rats. In conclusion rHuEPO has a potent erythropoietic action and it is possible to cure the anemia caused by renal failure.

Anemia↗
PubMed1990

Neoplastic angioendotheliosis: demonstration of immunoglobulin gene rearrangements by the Southern blot hybridization technique.

Using the Southern blot hybridization technique, two cases of 'neoplastic angioendotheliosis' (NAE) were examined for immunoglobulin gene rearrangements. For DNA analysis, frozen kidney (Case 1) and lung (Case 2) tissue, in which intravascular neoplastic cells were abundant, were used. In each case rearrangements were observed in both heavy and light chain genes. On examination of the heavy chain gene, the JH DNA probe detected one rearranged band in Case 1 and two in Case 2 after EcoRI digestion. On examination of the light chain genes, the C kappa DNA probe revealed one rearranged band in Case 1 and two in Case 2 after BamHI digestion, while the C lambda 2 DNA probe revealed only germline configurations after EcoRI digestion in each case. Thus, B-lymphocytic differentiation at the gene level was demonstrated in neoplastic cells in both cases. Since no more than two rearrangements were detected in each immunoglobulin gene, the intravascular neoplastic cells were considered to be monoclonal in nature.

Aged↗
PubMed1990

Multiple keratoacanthomas with peculiar manifestations and course.

The case of a 60-year-old Japanese man with unique multiple keratoacanthomas is reported. The lesions were located in the perioral area, grew peripherally, and healed centrally. Although individual lesions spontaneously regressed, prompt recurrence was observed after excision. Biopsy specimens taken from early proliferative, fully developed, and regressing stages revealed keratoacanthoma. Involucrin was demonstrated in the lesions during development and resolution. The early stage showed homogeneous staining of moderate intensity in the tumor cells at the suprabasal layers, and the staining became slightly irregular and intense when the lesions were fully developed. During resolution the intensity was markedly diminished. These results suggest that preterminal squamous differentiation accelerated during development of the tumors.

Diagnosis, Differential↗
PubMed1990

Characterization of mutations in the factor VIII gene by direct sequencing of amplified genomic DNA.

In order to search for mutations resulting in hemophilia A that are not detectable by restriction analysis, three regions of the factor VIII gene were chosen for direct sequence analysis. Short segments of genomic DNA of 127 unrelated patients with hemophilia A were amplified by polymerase chain reaction. A total of 136,017 nucleotides were sequenced, and four mutations leading to the disease were found: a frameshift at codon 360 due to deletion of two nucleotides (GA), a nonsense codon 1705 due to a C----T transition, and two missense codons at positions 1699 and 1708. The first missense mutation (A----T) results in a Tyr----Phe substitution at a putative von Willebrand factor binding site. The second results in an Arg----Cys substitution at a thrombin cleavage site. In addition, we identified three rare sequence variants: a silent C----T transition at codon 34 which does not result in an amino acid change, a G----C change at codon 345 (Val----Leu), and an A----G change at the third nucleotide of intron 14. Direct sequence analysis of amplified DNA is a powerful but labor-intensive method of identifying mutations in large genes such as the human factor VIII gene.

Base Sequence↗
PubMed1990

Use of denaturing gradient gel electrophoresis to detect point mutations in the factor VIII gene.

Point mutations in the factor VIII gene are responsible for the majority of cases of hemophilia A, and only a small fraction of these mutations can be recognized by restriction endonuclease analysis. We have now used polymerase chain reaction and denaturing gradient gel electrophoresis to characterize single nucleotide substitutions in the factor VIII gene. Five regions of the gene were studied: exon 8, the 3' end of exon 14, exon 17, exon 18, and exon 24. A GC clamp was attached to the 5' PCR primer to allow detection of the majority of single base changes in DNA fragments ranging from 249 to 356 bp. Ten of eleven known point mutations were definitively separated. Fifty-two patients with unknown mutations were then studied by these methods, and the disease-producing mutation was found in three. First, we identified a new missense mutation in exon 14 which is the likely cause of hemophilia A in one patient (tyrosine changed to cysteine at amino acid residue 1709). Second, we found a new missense mutation in exon 18 in one patient (asparagine to aspartic acid at amino acid residue 1922). Third, a previously described mutation in exon 24 was detected (arginine changed to glutamine at amino acid residue 2209). In addition, a new polymorphic nucleotide substitution was found in intron 7. Moreover, these mutations can be detected when the GC-clamped PCR products from all five regions are run in the same denaturing gel. Our results indicate that denaturing gradient gel electrophoresis can be successfully applied to the analysis of point mutations in large genes whose transcripts are not readily available.

Base Sequence↗
PubMed1990

Experimental autoimmune uveoretinitis in mice. Induction by a single eliciting event and dependence on quantitative parameters of immunization.

Experimental autoimmune uveoretinitis (EAU) in the mouse is a recently developed model of ocular autoimmunity. Dependence of disease induction on qualitative and quantitative parameters of immunization was studied in B10.A mice immunized with interphotoreceptor retinoid-binding protein (IRBP). It was found that use of Bordetella pertussis adjuvant as well as its mode of preparation was of critical importance for disease induction; no disease was induced if pertussis adjuvant was omitted. The minimal effective protocol for EAU induction when the vaccine form of B. pertussis adjuvant was used consisted of pretreatment with cyclophosphamide, two divided doses of IRBP in complete Freund's adjuvant (CFA), and two divided doses of B. pertussis vaccine. Any reduction in the immunization schedule resulted in reduced incidence of disease. In contrast, substituting purified B. pertussis toxin (PTX) for the vaccine allowed reduction of the immunization schedule to a single dose of IRBP in CFA and omission of the cyclophosphamide pretreatment. Severity and incidence of disease could be quantitatively controlled by varying the respective doses of IRBP and PTX. In addition, a chronic or an acute clinical course of EAU could be obtained by using either a low-dose or a high-dose immunization, respectively. Establishment of a single dose induction protocol and the quantitation of the immunopathogenic response as a function of the variables of immunization lay the foundation for the further development and utilization of this promising model of ocular autoimmunity.

Adjuvants, Immunologic↗
PubMed1990

Anti-tumour efficacy of mouse spleen cells separated with Dolichos biflorus lectin (DBA) in experimental pulmonary metastasis of B16 melanoma cells.

Anti-tumour effector cells were generated through 4 days culture of normal C57BL/6 splenocytes in a medium containing concanavalin A supernatant and then fractionated with Dolichos biflorus lectin (DBA) into DBA+ (agglutinable with DBA) and DBA- (non-agglutinable with DBA) cells. The DBA- cells, infused intravenously into mice together with B16 melanoma cells, or adoptively transferred into mice 3 days after the injection of B16 cells, caused a marked decrease in the number of lung nodules, while the DBA+ cells exerted no effect. On the other hand, the DBA+ cells exhibited higher cytolytic activity in vitro than the DBA- cells in short-term 51Cr-release assays. Then, we analysed the mechanism of the strong anti-tumour activity of DBA- cells in vivo. We found that DBA- cells showed higher response to recombinant interleukin-2 (rIL-2) than DBA+ cells and proliferated very well with a small amount of IL-2. In addition, DBA- cells adhered more strongly to lung endothelial cells than DBA+ cells in response to rIL-1 or rTNF. Furthermore, DBA- cells produced larger amounts of macrophage activating factor (MAF) including IFN-gamma when cultured with B16 melanoma. Taken together, our results show that DBA- cells are effective in reducing experimental pulmonary metastases not only by the direct lytic activity but also by the indirect killing activity through the activated macrophage.

Animals↗
PubMed1990

Physicochemical and biological comparison of recombinant human erythropoietin with human urinary erythropoietin.

Physicochemical and biological properties of recombinant human erythropoietin (rhEPO) were compared with human urinary erythropoietin (uEPO). uEPO and rhEPO were purified to apparent homogeneity from the urine of patients with aplastic anemia and from the conditioned medium of Chinese hamster ovary (CHO) cells transfected with a cDNA clone for human EPO, respectively. The microheterogeneous nature of both factors, observed on isoelectric focusing, is derived from the difference of the number of terminal sialic acid residues bound to the carbohydrate chains of the EPO molecule. The primary structure of rhEPO, consisting of 165 amino acid residues, was determined, and the C-terminal arginine predicted from the cDNA sequence was confirmed to be missing, as described previously (Recny et al. (1987) J. Biol. Chem. 262, 17156). Three N-glycosylation and one O-glycosylation sites of both factors were determined as Asn24, Asn38, and Asn83 and Ser126, respectively. Two disulfide linkages are located between Cys7 and Cys161, and between Cys29 and Cys33, in both EPOs. Hematogenic potencies of rhEPO and uEPO compared in normal and in partially nephrectomized rats were approximately the same. Both factors also stimulated the colony formation of CFU-E, BFU-E, and CFU-Meg in a dose-dependent manner. From these results, it is concluded that rhEPO produced in CHO cells transfected with cDNA clone for human EPO is indistinguishable from uEPO physicochemically and biologically, and is valuable for further research and for clinical use.

Amino Acid Sequence↗
PubMed1990

Effects of recombinant human erythropoietin on anaemic W/Wv and Sl/Sld mice.

The effects of recombinant human erythropoietin (rHuEPO) on anaemic W/Wv and Sl/Sld mice were investigated. rHuEPO was injected every day for a week in doses up to 86,000 iu/kg. Wv/+ and Sld+ mice, which have genetically a weak anaemia, received 17 or 86 iu/kg of rHuEPO and showed dose-dependent increases in haemoglobin, PCV, RBC and reticulocytes to the same extent as that in normal mice. W/Wv mice also showed increases in the haematological parameters in response to 8600 iu/kg of rHuEPO but the dose was much higher than that for normal mice. A reticulocyte increase in W/Wv mice appeared later than in normal mice and was not sustained for 2 weeks even though the rHuEPO treatment was continued. Sl/Sld mice, however, did not show any significant haematological effect from doses up to 86,000 iu/kg. In both W/Wv and Sl/Sld mice receiving 8600 and 86,000 iu/kg of rHuEPO, respectively, an increase in splenic or bone marrow CFU-E was observed regardless of the defect in their haemopoietic systems. The plasma erythropoietin (EPO) level in W/Wv and Sl/Sld mice was inversely correlated with the haemoglobin, indicating that EPO production was not influenced by the haemopoietic defect and was regulated by the hypoxic properties of the anaemia. These results indicate that a large dose of exogenous rHuEPO is effective for the anaemia in W/Wv mice caused by a stem cell defect but not for the anaemia in Sl/Sld mice caused by a defective microenvironment.

Anemia, Macrocytic↗