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Biomedical subjects

K Nagakura

Publications and source records attributed to K Nagakura.

At least 19 recordsLinked to original sources
PubMed2001

Invasive forms of Toxoplasma gondii, Leishmania amazonensis and Trypanosoma cruzi have a positive charge at their contact site with host cells.

We examined the surface charges of invasive forms of Toxoplasma gondii, Leishmania amazonensis, and Trypanosoma cruzi by atomic force microscopy and surface potential spectroscopy. We found that the specific part of the protozoan which makes initial contact with the host cell is positively charged. This indicates that the positive charge at the site of contact facilitates binding of the invasive protozoan to negatively charged host cells.

Animals↗
PubMed2001

[Clinical efficacy of leuprolide acetate and combined treatment with estramustine for advanced prostate cancer].

BACKGROUND/PURPOSE: Twenty-two institutes have organized Keio University Prostate Cancer Study Group to study clinical efficacy and safety of Leuprolide acetate (Leuplin) for the treatment of advanced prostate cancer (clinical stage D1 and D2). Cotreatment of Leuplin and Estramustine phosphate disodium (Estracyt) has been performed to investigate its clinical efficacy. MATERIALS AND METHODS: One hundred and two cases of advanced prostate cancer were treated either with Leuplin alone (group I), Leuplin and Estracyt (group II) or Estracyt alone (group III). After 12 weeks treatment, clinical effects against subjective symptoms (pain, voiding difficulty, performance status and body weight), serum testosterone level, tumor size and serum PSA level were examined to investigate short-term effect of each treatment. The treatment had been continued for 24 months and the treatment effects including progression free survival and overall survival were analyzed. RESULTS: Clinical efficacy after 12 weeks treatment were examined among 97 cases (group I; 35 cases, group II; 36 cases, group III; 26 cases). The background of those patients in each group was statistically equal. Treatment effects against subjective symptoms and serum testosterone level statistically revealed no significant difference among 3 groups. Treatment effects against primary tumor, bone metastatic lesion, lymphnode metastatic lesion and serum PSA level were investigated and anti-tumor effect was characterized by total efficacy rate (complete remission rate plus partial remission rate) of each treatment group. Treatment efficacy rates for each lesion and PSA demonstrated no statistical difference among 3 treatment groups. Total efficacy rate of group I, II and III were 88.2%, 84.0% and 78.3%, respectively, which statistically revealed no significant difference. Total efficacy rate of each group after completing 24 months treatment was; group I 80.0%, group II 55.6% and group III 83.3%, which statistically showed no significant difference among 3 treatment groups. The median day for progression free survival of group I, II and III were 661, 731 and 517, respectively. The overall survival rate of group I, II and III after completing 24 months treatment were 77.5%, 83.0% and 72.4%, respectively. Both progression free survival rates and overall survival rates revealed no significant difference among 3 groups. Side effects during 24 months treatment were seen in 8.6% of group I, 47.2% of group II and 26.9% of group III, and these occurrence rates were significantly different among the groups (p = 0.0013). CONCLUSION: Although number of the cases had not been able to continue the treatment for their side effects, the statistical characterization demonstrated that cotreatment of Leuplin and Estracyt had no greater treatment effect than monotreatment of each drug.

Aged↗
PubMed2000

Asymptomatic cyst passers of Entamoeba histolytica but not Entamoeba dispar in institutions for the mentally retarded in Japan.

Entamoeba histolytica/Entamoeba dispar was isolated from 50 asymptomatic amebic cyst passers in three institutions for the mentally retarded in Kanagawa Prefecture, Japan. To distinguish between E. histolytica and E. dispar, the isolates were analyzed by PCR, reactivity to monoclonal antibodies, and zymodemes. All isolates were identified as E. histolytica. The results lead us to conceive that, in Japan, E. histolytica is predominant even in asymptomatic cyst passers.

Animals↗
PubMed2000

Gnathostomiasis possibly caused by Gnathostoma malaysiae.

Gnathostomiasis is rarely reported in travelers, although the disease remains a major public health problem in Southeast Asia. A creeping eruption and Quincke's edema (slowly migrating erythema with pruritus) appeared in two Japanese men who had eaten raw freshwater shrimp in Myanmar. A Gnathostoma larva was found in subcutaneous tissue from one of the men. Four species causing human gnathostomiasis, G. hispidum, G. doloresi, G. nipponicum and G. spinigerum, can be distinguished based on the number of nuclei in intestinal epithelial cells of infected larvae, in cross-section. In G. hispidum, only a single large nucleus is found. Morphologically, our larva was initially identified as G. hispidum. However, since the number of epithelial cells was greater and the body width was larger than those of a "large-type" 3rd-stage larva of G. hispidum, the larva was then identified as a 3rd-stage larva of G. malaysiae, Miyazaki and Dun, 1965, as reported by Setasuban et al, (1991). Since no human cases caused by this species of Gnathostoma have previously been encountered, this appears to be the first report of gnathostomiasis due to G. malaysiae.

Animals↗
PubMed1999

Cystic partially differentiated nephroblastoma in an adult: an immunohistochemical, lectin histochemical and ultrastructural study.

AIMS: Cystic partially differentiated nephroblastoma (CPDN) is an uncommon renal multicystic tumour, usually affecting early infants. To our knowledge, this report describes the first case of CPDN occurring in an adult. METHODS AND RESULTS: A 45-year-old man was found incidentally to have a left renal cystic tumour, measuring 20 mm in diameter, at the lower pole far from the pelvis. The tumour was composed of multilocular cystic spaces of variable size and intervening septa without solid nodular areas. The cysts were lined by a single layer of flattened, hobnail, or columnar epithelium. The septa were made of mesenchymal cells, which were admixed with small numbers of loosely aggregated blastemal cells, occasional tubular structures in various stages of development, and a few glomeruloid structures. The tumour cells had no anaplasia, and mitoses were rare. Immunohistochemical and lectin histochemical studies revealed that the cyst lining epithelium and the tubular structures in the septa expressed predominantly the markers for distal tubules and collecting ducts. Ultrastructurally, the cyst lining cells closely resembled collecting duct cells while some tubular structures showed an immature nephrogenic morphology. The patient was alive and well without evidence of recurrence 11 months after surgery. CONCLUSIONS: CPDN does occur in adults, as experienced in Wilms' tumour, though its incidence is extremely low. This study suggests that CPDN may show maturation intermediate between cystic nephroma and Wilms' tumour, even in adult cases.

Biomarkers, Tumor↗
PubMed1998

Total resolution of 17 DL-amino acids labelled with a fluorescent chiral reagent, R(-)-4-(3-isothiocyanatopyrrolidin-1-y1)-7-(N,N-dimethylaminosulfonyl)- 2,1,3-benzoxadiazole, by high-performance liquid chromatography.

Total resolution of 17 DL-amino acids after derivatization with a fluorescent chiral tagging reagent, 4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfony l)-2,1,3- benzoxadiazole [R(-)-DBD-PyNCS], was studied by reversed-phase liquid chromatography. The reaction of the reagent with amino acids proceeds effectively at 55 degrees C for 20 min in the presence of 1% TEA to produce the corresponding fluorescent diastereomers (excitation at 460 nm, emission at 550 nm). Each pair of the resulting derivatives was efficiently separated with water-acetonitrile containing 1% acetic acid as the mobile phase. Peak resolution was in the range of 0.92 (DL-Arg)-9.8 (DL-Cys). Although mutual separation of some DL-amino acids was possible using the elution solvent, simultaneous resolution of 17 DL-amino acids was difficult with a single chromatographic run, even if some gradient elutions were adopted. Therefore, both gradient and isocratic elution systems were used for total resolution of the DL-amino acids. Thus, 17 DL-amino acids were well resolved by a gradient and an isocratic elution systems. The proposed derivatization and elution methods were applied to the determination of DL-amino acids in yogurt. The results showed that some of the L-amino acids, i.e., Glu, Asp, Ser, Gly, Ala, Thr, Pro, Lys, Phe and Met, were found in the methanol extracts of yogurt. On the other hand, the D-amino acids that were identified in the extracts were D-Glu, D-Asp and D-Ala, and the mean % to each L-amino acid were 11.9% (D-Glu), 27.6% (D-Asp) and 56.7% (D-Ala), respectively.

Amino Acids↗
PubMed1998

Brief survey of common intestinal parasites in the Tokyo Metropolitan Area.

Since 1955, when sanitary conditions were poor, the incidence of intestinal parasitism has steadily decreased. Similarly, the number of requests for fecal examinations by physicians has also decreased. However, in our hospital, the incidence of parasites detected in fecal material has been increasing since 1994, regardless of the decreasing number of stool exams performed. Possible reasons for this situation can be summarized as follows: First, an effective drug for treating Trichuris trichiura and Enterobius vermicularis infections has reduced the incidence of these two helminths. Second, an apparent increase in the incidence of infections with the tapeworms Diphyllobothrium latum and Diplogonoporus grandis may just be a reflection of patients gathering at a few facilities for treatment. Third, the number of individuals infected with a single Ascaris is significantly increasing. Fourth, parasites related with travel abroad (Schistosoma haematobium and Opisthorchis viverrini) are appearing due to the increase in travel to and from foreign countries. Of the above, we think particular attention should be paid to the increase in A. lumbricoides infections.

Ascariasis↗
PubMed1998

Diagnosis of kala-azar by nested PCR based on amplification of the Leishmania mini-exon gene.

To diagnose visceral leishmaniasis (kala-azar), we have developed a nested PCR method based on amplification of the mini-exon gene, which is unique and tandomly repeated in the Leishmania genome. Nested PCR was sufficiently sensitive for the detection of DNA in an amount equivalent to a single Leishmania parasite or less. We examined the usefulness of this PCR method using bone marrow aspirates and buffy coat cells collected from kala-azar patients who had or had not received chemotherapy in northwest China. We obtained PCR positivity for all of the parasitologically positive bone marrow samples from the patients. Some ambiguities with the primary PCR results were eliminated by the subsequent nested PCR. The buffy coat samples from 7 of 12 patients with splenomegaly were positive by the nested PCR, although only 2 of them were positive for parasites by culture. However, buffy coat samples from nine children, whose splenomegaly has been reduced and clinically cured by antimony treatment, were all negative. Thus, this nested PCR method represents a new tool for the diagnosis of kala-azar with patient blood samples instead of bone marrow or spleen aspirates obtained by more invasive procedures.

Adolescent↗
PubMed1998

[Clinical study on cystinuria in children--the stone management and the prevention of calculi recurrence].

BACKGROUND: Cystinuria is an autosomal recessive disorder, and primary manifestation is the repeated formation of cystine calculi. Little information is available regarding clinical course of pediatric cystinuria having followed into adulthood. We report our experience with the management and the clinical course on cystinuria in children, who have been followed up for relatively long time. MATERIALS AND METHODS: We retrospectively reviewed the records of all pediatric patients with cystinuria in whom urolithiasis was treated from 1970 to 1996. RESULTS: A total of 15 pediatric patients with cystine calculi (9 boys, 6 girls) were treated in our hospital. Average age at diagnosis was 3 years 4 months old. Mean follow-up was 104 months. Stone location was upper urinary tract in 11 cases, bladder in 3 cases and both upper urinary tract and bladder in 1 case. Medical treatments including hydration, urine alkalization and dissolution therapy were performed in all patients. In three cases whose urinary cystine level ranged from 138 to 326 mg/gCr, cystine calculi were disappeared by medical therapy alone. In one of 3 cases vesicoureteral reflux was identified. Side effects were noticed in 30.0% of patients with tiopronin and in 85.7% of those with D-penicillamine, especially in 1 case with tiopronin nephrotic syndrome being noticed. Surgical procedures were performed in 13 patients (lithotomy: 17 calculi, endourology: 7 calculi and ESWL: 7 calculi). The stone free rate was 100% with lithotomy, 80 to 100% with endourology and 43% with ESWL at an average of 5.9 procedures. No complications were recognized after the surgical treatments. The stone events of 15 patients ranged from 0 to 1.5 (average 0.55). In all six patients followed up over the age of 20 years, stone recurrences were observed exclusively between 17 and 20 years of age. CONCLUSION: Dissolution therapy is more effective for cystinuric patients in whom urinary cystine excretion is less than 330 mg/gCr. For those cases with low urinary cystine level it is necessary to evaluate structural abnormalities of the urinary tract to avoid stone recurrence. ESWL and endourology should be tried for pediatric cystinuria except for neonates and infants, considering its safety. The patients and their parents must have adequate knowledge about the disease itself and its management. Prevention of cystine calculi recurrences depends on patient compliance to the therapeutic regimens necessitating close follow up according to the clinical conditions, especially for those in pubertic or postpubertic age.

Adolescent↗
PubMed1998

Detection of fowl mites inside two hospital rooms.

Many mites were found on bookshelves near the windows in 2 rooms of the Department of Pediatrics on the 4th floor in the Tokai University Hospital. Fortunately, nobody reported being bitten by, or experiencing itching due to, the mites. The arthropods were tentatively identified as adults of the northern fowl mite, Ornithonyssus sylviarum (Canestrini et Frazago, 1877), commonly called "Torisashi-dani" in Japanese. It appears the mites came from an empty wagtail nest which was outside the windows. Since migrating birds like the wagtail may carry O. sylviarum and other pests and pathogens, and their possible transfer to domestic birds, more attention should be paid to the danger posed by bird mites.

Animals↗
PubMed1998

Leishmania mini-exon genes for molecular epidemiology of leishmaniasis in China and Ecuador.

The mini-exon gene is unique and is tandemly repeated in the Leishmania genome. The transcribed region is highly conserved, but the non-transcribed spacer region is distinct in length and in sequence among different Leishmania species. The usefulness of PCR amplification of the Leishmania mini-exon gene was examined for molecular epidemiology of visceral and cutaneous leishmaniasis. We previously described a PCR method for amplification of the mini-exon gene and obtained positive amplification in bone marrow aspirates of patients with visceral leishmaniasis in China. In this study, we have cloned and sequenced two PCR products from the patients. The sequences of two products revealed 100% identity and showed more similarity to the mini-exon gene of L. donovani Indian strain than those of L. donovani complex in Africa and South America. We also applied this PCR method to the diagnosis of cutaneous leishmaniasis. We obtained positive PCR amplification in skin biopsy materials taken from patients with cutaneous leishmaniasis in Ecuador. Since this PCR amplification is simple and requires only a pair of primers to detect all Leishmania species distributed in Ecuador, the method may be a useful tool for the detection of parasites, not only from patients, but also from sandflies and reservoir animals in this area of endemicity.

Animals↗
PubMed1996

Distinctive serial magnetic resonance changes in a young woman with rapidly evolved neurocysticercosis, with positron emission tomography results.

A woman aged 21 years noticed numbness of the left hand, dysarthria, and right hemiparesis. Magnetic resonance imaging (MRI) showed homogeneously enhanced lesions in the bilateral cerebral white matter; these enlarged within 2 weeks, showing ring-like enhancement, and then spontaneously decreased in size and enhancement. Neurocysticercosis was confirmed by repeated, significantly positive serology results and the dramatic response to praziquantel. Subsequently, positron emission tomography (PET) revealed persisting regions of possibly decreased cerebral uptake of [18F]2-fluoro-2-deoxyglucose. This is the first documentation of such distinctive serial MRI changes and the results of PET in neurocysticercosis.

Adult↗
PubMed1996

[Invasive amebiasis at an institution for the mentally retarded in Shizuoka Prefecture].

Amebiasis caused by Entamoeba histolytica at an institution for mentally retarded in Shizuoka Prefecture is reported. Five of the 50 patients showed E. histolytica cysts in their stools and 4 were positive serologically. The polymerase chain reaction and restriction fragment length polymorphism revealed that the isolates were pathogenic-type E. histolytica. Epidemiological analysis revealed that the amebic infection was caused by the abnormal behavior of mentally retarded patients. Administration of diloxanide furoate and metronidazole for cyst-carriers eliminated cysts from the stool and lowered the antibody titer.

Adult↗
PubMed1992

Serologic findings in hepatic ascariasis: a case report.

A 56-year-old Japanese woman underwent partial hepatectomy for intrahepatic cystic masses. Before operation, the patient had been diagnosed as liver abscess due to Ascaris infection serologically. The excised hepatic lesions consisted of encapsulated old abscesses, with a few calcified parasitic ova and numerous Charcot-Leiden's crystals microscopically seen in necrotic exudate. However, no parasitic worms were found in the cystic cavity. The eggs in the tissues were indistinguishable from other helminthic ova morphologically, but stained positively for Ascaris antigens by the indirect immunoperoxidase method. The results indicate that the serologic diagnosis of intrahepatic ascariasis may be feasible, practical, and reliable.

Animals↗