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M Koga

Publications and source records attributed to M Koga.

At least 55 records · Page 3Linked to original sources
PubMed2002

Conventional multiple or microdissection testicular sperm extraction: a comparative study.

BACKGROUND: Testicular sperm extraction (TESE) with ICSI is becoming the first-line treatment for non-obstructive azoospermia (NOA). Recently, the sperm retrieval rate (SRR) by microdissection TESE was reported to be higher than by conventional TESE. However, a comprehensive comparison between multiple and microdissection TESE patients including histological findings has not been reported. METHODS: Patients with NOA who underwent microdissection TESE (n = 56) or multiple TESE (n = 37) were compared. Pre-operative characteristics were similar between groups. In addition, microscopic findings during microdissection TESE also were investigated. RESULTS: Operative time was significantly longer for microdissection TESE than for multiple TESE. Histological examination suggested that spermatogenesis was relatively more impaired in the microdissection TESE group than in the multiple TESE group. Despite this, SRR by microdissection TESE (42.9%) appeared higher than by conventional TESE (35.1%) although this observation failed to reach statistical significance. Seventeen of 26 patients (65.4%) with heterogeneous tubule were successful for sperm retrieval. No severe operative complications occurred in any patient in either group, and no patient required post-operative hormone replacement to treat hypogonadism. CONCLUSIONS: Microsurgical technique is safe and may improve SRR for TESE in a variety of patients with NOA, especially patients with heterogeneous testicular tubules.

Adult↗
PubMed2002

Anti-GT1a IgG in Guillain-Barré syndrome.

OBJECTIVE: To investigate the presence of serum anti-GT1a IgG in Guillain-Barré syndrome (GBS) and its relation to clinical manifestations. BACKGROUND: Several patients with GBS and bulbar palsy have been reported to have serum anti-GT1a IgG. Most, however, also have anti-GQ1b IgG. A previous study failed to detect GT1a in human cranial nerves, but GQ1b was abundant in human ocular motor nerves. Whether anti-GT1a IgG itself determines the clinical manifestations is not yet clear. METHODS: The association of clinical manifestations with the presence of anti-GT1a IgG and with its cross reactivity was investigated. An immunochemical study was performed to determine whether GT1a is present in human cranial nerves. RESULTS: Anti-GT1a and anti-GQ1b IgG were positive in 10% and 9% respectively of 220 consecutive patients with GBS. Patients with anti-GT1a IgG often had cranial nerve palsy (ophthalmoparesis, 57%; facial palsy, 57%; bulbar palsy, 70%), and 39% needed artificial ventilation. These features were also seen in patients with anti-GQ1b IgG. There was no significant difference between the two groups with respect to the frequency of clinical findings. An enzyme-linked immunosorbent assay showed that anti-GT1a IgG cross reacted with GQ1b in 75% of the patients, GD1a in 30%, GM1 in 20%, and GD1b in 20%. All five patients who carried anti-GT1a IgG that did not cross react with GQ1b had bulbar palsy, neck weakness, absence of sensory disturbance, and positive Campylobacter jejuni serology. Thin-layer chromatography with immunostaining showed that GT1a is present in human oculomotor and lower cranial nerves. CONCLUSIONS: These findings provide further evidence that anti-GT1a IgG itself can determine clinical manifestations. The distinctive clinical features of patients with anti-GT1a IgG without anti-GQ1b activity distinguish a specific subgroup within GBS.

Adult↗
PubMed2001

Differential immune response to gangliosides in Guillain-Barré syndrome patients from Japan and The Netherlands.

Anti-ganglioside antibodies are consistently found in Guillain-Barré syndrome (GBS) patients from different geographical parts of the world. Several studies indicated differences in relative frequencies of anti-ganglioside reactivity and isotype distribution between GBS patients from Asia and from Europe. We investigated antibody reactivity against the gangliosides GM1, GM1b and GalNAc-GD1a in GBS patients from Japan and The Netherlands in two different laboratories. The proportion of GBS patients with anti-ganglioside antibodies did not differ between the two countries. GBS patients from The Netherlands more frequently had cross-reacting anti-GalNAc-GD1a/anti-GM1b antibodies and a stronger IgM anti-ganglioside response. Our findings indicate that geographical determined factors, dependent on either the host or the triggering infectious agent, determine the isotype distribution and fine specificity of anti-ganglioside antibodies in GBS patients.

Adolescent↗
PubMed2001

Functional analysis of the propeptides of subtilisin E and aqualysin I as intramolecular chaperones.

Several proteases require propeptides for the correct folding of their own protease domain. We have recently found that the propeptide from a thermostable subtilisin homolog aqualysin I can refold subtilisin BPN' when added in trans. Here, we constructed chimeric genes with subtilisin E and aqualysin I to attempt the in cis folding of subtilisin E by means of the propeptide of aqualysin I. Our results indicate that the propeptide of aqualysin I can to some extent chaperone the intramolecular folding of the denatured subtilisin E. These results suggest that propeptides in the subtilisin family, despite their sequence diversity, have similar functions. Further, some enzymatic properties of some chimeras in which the subtilisin mature domain is partly swapped with that of aqualysin I were shown to be more similar to those of aqualysin I.

Bacillus subtilis↗
PubMed2001

Acute sensory ataxic neuropathy associated with monospecific anti-GD1b IgG antibody.

The authors describe two patients with acute sensory ataxic neuropathy. Both had a profound loss of proprioception and generalized areflexia. High titers of monospecific anti-GD1b IgG antibody were detected in their sera during the acute phase. Sensory ataxia resolved within 2 weeks after the onset. Taken together with the induction of experimental sensory ataxic neuropathy sensitized with GD1b ganglioside, GD1b may be a target molecule for autoantibody in some patients with acute sensory ataxic neuropathy.

Acute Disease↗
PubMed2001

Multidrug resistance-associated protein 3 is a tumor rejection antigen recognized by HLA-A2402-restricted cytotoxic T lymphocytes.

The identification of tumor rejection antigens recognized by CTLs and its application in peptide-based specific immunotherapy against melanomas have been extensively investigated in the past decade. However, only a small number of studies regarding these issues in other epithelial cancers have been reported. In this study, we show that a multidrug resistance-associated protein 3 (MRP3) is a tumor rejection antigen recognized by HLA-A2402-restricted CTLs established from T cells infiltrating into lung adenocarcinoma. MRP3 is expressed in differing quantities in tumor cells of various tissue types and origins. Four dominant MRP3-derived antigenic peptides that are recognized by the CTLs have been identified, each possessing in vitro immunogenicity. Namely, these four peptides (MRP3-503, MRP3-692, MRP3-765, and MRP3-1293) can induce peptide-specific CTLs after in vitro stimulation with these peptides in peripheral blood mononuclear cell cultures of HLA-A24(+) cancer patients, with the CTLs expressing cytotoxicity against HLA-A2402(+) MRP3(+) tumor cells but not against either HLA-A2402(-) or MRP3(-) target cells. The peptide specificity of the cytotoxicity of the CTLs was further confirmed by using peptide-loaded HLA-A24(+) EBV-transformed B cells. Widespread MRP3 expression in various tumor cell lines and tumor tissues at the mRNA level was confirmed. Furthermore, reactivities of the MRP3-peptide-induced CTLs against tumor cells correlated with MRP3 expression in the tumor cells. These results suggest that MRP3 and its derived peptides described in the present paper are potential candidates for cancer vaccines in regard to HLA-A24(+) patients with various tumors, particularly for those tumors that show anticancer drug resistance.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2001

Nematocidal activities of thiabendazole and ivermectin against the larvae of Strongyloides ratti and S. venezuelensis.

With the aim of developing therapeutic agents for strongyloidosis, the disease caused by infection with Strongyloides stercoralis, we established a novel assay technique using S. ratti and S. venezuelensis as models for S. stercoralis. The newly developed assay technique was found to more accurately represent treatment-induced larval paralysis than existing assays. Our method uses paper disks impregnated with the test solution, which even allows materials that are sparingly soluble in water to be tested. An inverted microscope was used to observe the larval states, and these states were recorded using a digital camera. We observed the activities of ivermectin and thiabendazole against larvae and calculated larval motility and velocity. These two factors were then combined to determine the overall viability of larvae at selected concentrations. The activities of the anthelmintics were compared by calculating the concentrations at which 50% viability was demonstrated, or in other words, the concentration at which paralysis was caused in 50% of the individuals (50% paralysis concentration; PC(50)). Evaluations after 24h of exposure yielded the following reproducible PC(50) values for ivermectin and thiabendazole, respectively: S. ratti, 2.4 and 140 microM; and S. venezuelensis, 2.3 and 190 microM. After treatment with ivermectin, there was a tendency for larval motility to be greater than that of the controls at low concentrations, a result that might be associated with its mechanism of action.

Animals↗
PubMed2001

Miller Fisher syndrome and Haemophilus influenzae infection.

OBJECTIVE: To examine the association between Miller Fisher syndrome (MFS) and antecedent Haemophilus influenzae infection. BACKGROUND: Little is known about agents in prior respiratory tract infection of MFS, whereas antecedent upper respiratory symptoms are frequent. H. influenzae is a major pathogen that can cause human respiratory tract infection. METHODS: The authors used ELISA to detect serum antibody against the bacterium in 70 consecutive patients with MFS and 110 with Guillain-Barré syndrome (GBS). RESULTS: Serum anti-H. influenzae IgG and IgM antibody activities were significantly higher in the MFS group than in age- and sex-matched patients with other neurologic diseases (n = 62) and normal control subjects (n = 82). The GBS group showed no significant increase in any class of antibody activities compared with control groups. Serologic evidence of recent infection was found in five (7%) of the patients with MFS and two (2%) of 110 patients with GBS, all of whom had a history of antecedent respiratory tract infection. They frequently showed ophthalmoplegia, but other neurologic features were not remarkable. Serum anti-GQ1b IgG antibody that had cross-reactivity with GT1a ganglioside was detected in six of these seven patients. Thin-layer chromatography with immunostaining showed that serum IgG from H. influenzae-seropositive patients with high anti-GQ1b and anti-GT1a IgG antibody titers bound to the lipopolysaccharide fraction extracted from the type b H. influenzae serostrain. These bands were also stained by anti-GT1a monoclonal antibody (GMR11), indicating that the lipopolysaccharide bears the GT1a epitope. CONCLUSIONS: These findings point to H. influenzae being an agent associated with MFS. Epitopic overlap between H. influenzae and human nerve tissue may be involved in the development of MFS much as GBS is associated with Campylobacter jejuni enteritis.

Adolescent↗
PubMed2001

Intravenous immunoglobulin therapy for Guillain-Barré syndrome with IgG anti-GM1 antibody.

To compare the effects of intravenous immunoglobulin (IVIg) therapy and plasmapheresis for the IgG anti-GM1-positive subtype of Guillain-Barré syndrome (GBS), clinical and electrophysiological recoveries were analyzed in 24 patients treated with IVIg (n = 10) or plasmapheresis (n = 14). At entry, there were no significant differences between the two patient groups in age, sex, clinical severity (Hughes grade), sum scores of distally evoked amplitudes of compound muscle action potentials (CMAPs), and frequency of Campylobacter jejuni infection. The patients treated with IVIg had significantly lower Hughes grade scores 1, 3, and 6 months after onset (P = 0.03), and a higher probability to regain independent locomotion at 6 months [P(logrank) = 0.044]. In the IVIg group, markedly rapid recovery (improvement by two or more Hughes grade scores within 4 weeks) was more frequent (6 of 10 vs. 3 of 14, P = 0. 03), and delayed recovery (unable to walk independently at 6 months) was less frequent (0 of 10 vs. 4 of 14, P = 0.06). CMAP sum score at 6 months tended to be greater for the IVIg group (P = 0.07). For the IgG anti-GM1-positive subgroup of GBS patients, IVIg therapy may be a more efficacious treatment than plasmapheresis.

Action Potentials↗
PubMed2001

7Li 2D CSI of human brain on a clinical scanner.

Lithium salts have been widely used in the treatment of mood disorders, but the mechanism of action is still not clear. In this work, a methodology for two-dimensional Lithium-7 imaging on clinical systems is presented. The data were acquired using a phosphorus volume head coil that was re-tuned for the Lithium-7 frequency. A spectroscopic sequence was used to acquire the free induction decay (FID) after volume excitation using a hard pulse. The results obtained on the head of patients undergoing lithium treatment (n = 7, 0.6 mEq/l average serum level) demonstrate that images of adequate signal to noise ratio (100:1) can be obtained in acceptable imaging times (55 min) using the proposed methodology. The distribution of 7Li appears uniform in the brains of the patients studied.

Brain↗
PubMed2001

Relationship between lymphocyte cyclosporin sensitivity and clinical progress of psoriasis.

Cyclosporin (CYA) is a therapeutic agent used in the treatment of psoriasis vulgaris. However, the effectiveness of CYA therapy varies among patients. In the present study, due to the fact that CYA mainly acts on lymphocytes, we hypothesized that a measurement of the sensitivity of lymphocytes to CYA in vitro (IC50) could be applied to patients with psoriasis vulgaris to determine therapeutic success. We measured IC50 levels of 32 patients presenting with psoriasis prior to CYA administration, and classified them into three groups according to IC50 levels: favorable, moderate and low sensitivity. CYA sensitivity levels were correlated with the degree of improvements in psoriasis area and severity index (PASI) scores, CYA dosage and occurrence of side-effects (hepatopathy and nephropathy). Results showed the degree of improvement in PASI scores differed significantly between the favorable and low sensitivity groups (P < 0.05). Furthermore, CYA dosage was lowest in the favorable sensitivity group and highest in the low sensitivity group. Moreover, hepatopathies and nephropathies were detected in the low and moderate sensitivity groups, but not in the favorable sensitivity group. These results suggest that the effectiveness of CYA therapy as a treatment of psoriasis vulgaris is affected by the sensitivity of lymphocytes in each patient.

Adult↗
PubMed2001

DAF-7/TGF-beta expression required for the normal larval development in C. elegans is controlled by a presumed guanylyl cyclase DAF-11.

In C. elegans development, unfavorable growth conditions lead a larva to an arrested and enduring form called a dauer. To elucidate components upstream of DAF-7/TGF-beta in this control pathway, we isolated a mutant that was defective in daf-7 promoter::gfp reporter expression and showed an arrested (dauer-constitutive) phenotype. It has a new mutation in the daf-11 gene encoding a transmembrane guanylyl cyclase. We show that daf-11 gene and a related gene daf-21 act upstream of daf-7, and cilium-related genes che-2 and che-3 are placed between daf-11 and daf-7, in the genetic pathway controlling dauer formation. Expression of daf-11 cDNA by cell specific promoters suggests that daf-11 acts cell autonomously in ASI chemosensory neurons for daf-7 expression.

Alleles↗
PubMed2001

Analysis of cooking oil fumes by ultraviolet spectrometry and gas chromatography-mass spectrometry.

This paper investigated the components, especially aldehydes, in the fume condensates from four kinds of cooking oil using ultraviolet (UV) spectrometry and gas chromatography-mass spectrometry (GC-MS). It was observed that there was a great change of the UV absorption spectra from the results of the unheated oil to the results of the fume after heat treatment (190-200, 230-240, and 270-280 degrees C). There was a strong peak within the wavelength range of 260-270 nm in each condensate sample. From the GC-MS results, it was tentatively deduced that there were some 2,4-dialkylenaldehydes and other conjugated compounds in the condensates. The results showed there were large amounts of hexanal and 2-heptenal in the cooking oil fume and that the total aldehyde peak areas of the condensates from four kinds of oil were around 30-50% of the total peak area at 270-280 degrees C.

Aldehydes↗
PubMed2001

Antecedent symptoms in Guillain-Barré syndrome: an important indicator for clinical and serological subgroups.

OBJECTIVES: To examine whether Guillain-Barré syndrome (GBS) can be classified in clinical and immunological subgroups based on the type of prior illness. Background - The existence of antecedent symptoms supports the diagnosis of GBS in patients who experience acute muscle weakness progression. However, little is known about additional meanings of determining antecedent symptoms. MATERIALS AND METHODS: Prospective investigation of prior infectious illness in GBS and related disorders (n=176). RESULTS: The frequent antecedent symptoms in GBS and related disorders were fever (52%), cough (48%), sore throat (39%), nasal discharge (30%), and diarrhea (27%). Patients who had sore throats or coughs frequently had ophthalmoparesis (respectively P=0.0004, P=0.001) and IgG anti-GQ1b antibody (P=0.01, P=0.007). Fever was associated with bulbar palsy (P=0.047) and headache with facial palsy (P=0.04). Patients with diarrhea often had anti-ganglioside IgG (anti-GM1 [P=0.0006] and anti-GM1b [P=0.008]), IgM (anti-GM1 [P=0.03], anti-GM1b [P=0.02], and anti-GalNAc-GD1a [P=0.047]) antibodies and rarely showed ophthalmoparesis or bulbar palsy (respectively P=0.02, P=0.04). Diarrhea and abdominal pain were closely associated with Campylobacter jejuni serology (respectively P<0.0001, P=0.01), whereas other symptoms were not related to pathogens such as cytomegalovirus, Epstein-Barr virus, or Mycoplasma pneumoniae. CONCLUSIONS: Our comprehensive study showed that GBS preceded by sore throat, cough, fever, headache, or diarrhea respectively forms clinical or serological subgroups, or both. This association is not necessarily dependent on infection by the known trigger pathogens.

Adolescent↗