Biomedical subjects

K Higuchi

Publications and source records attributed to K Higuchi.

At least 55 records · Page 3Linked to original sources

PubMed2000

[Infratemporal fossa approach for mid-skull base lesion: its usefulness, surgical anatomy, and intraoperative device].

The usefulness of the infratemporal fossa type C approach is reported through a presentation of a case of clival chordoma, which was successfully treated by this approach. Although it is complicated and includes some demerits, this approach gives a shorter and wider access to mid-skull base pathology than other approaches. Among the demerits, deformity of the temporal region caused by extensive drilling of the bone could be minimized by cosmetic mastoidectomy, which was first applied during this approach by the authors. The surgical anatomy for this approach is demonstrated using a cadaver specimen.

Adult↗

PubMed2000

Helicobacter pylori: criminal or innocent bystander?

Most patients with peptic ulcer disease are infected with Helicobacter pylori. However, the infection may not be always causative for the disease. The prevalence of H. pylori infection is about 50% in general. Therefore, half of the patients with peptic ulcer could be infected with this microorganism just by chance. In such cases, H. pylori may do nothing for the ulcer, although it causes chronic active gastritis. This could be the reason for the existence of both H. pylori-positive nonrecurring ulcers and ulcers that recur even after cure of H. pylori infection. H. pylori-positive non-recurring ulcers should be included in non-H. pylori ulcer disease in addition to H. pylori-negative ulcers. NSAIDs are the major cause of H. pylori-negative ulcers, especially H. pylori-negative gastric ulcers. However, more than 10% of ulcers recurred even after cure of H. pylori infection in nonusers of NSAIDs in a 7-year follow-up study. In the same study, 46% of ulcers did not recur in patients in whom eradication of H. pylori failed. There are few (<5%) H. pylori-negative ulcers; about 10% of ulcers recur after cure of H. pylori infection, and about 40% of H. pylori-positive ulcers do not recur. These are all non-H. pylori ulcers, and they represent 30% of all ulcers, which is the general prevalence rate for nonulcer subjects. Therefore, H. pylori may be an innocent bystander in approximately one third of all ulcer patients.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2000

Comparison of nasal and oral tolerance for the prevention of collagen induced murine arthritis.

OBJECTIVE: Administration of bovine type II collagen (CII) or of its peptide either orally or nasally has been reported to suppress the development of collagen induced arthritis (CIA) in mice and rats. We examined the inhibitory effects of CII delivered by each route on CIA in DBA/1J mice to determine which route was superior. METHODS: Male mice were injected twice with CII in Freund's complete adjuvant to induce CIA. Before induction of CIA, 1, 10, or 40 microg of CII were administered nasally 15 times and 10, 100, 500, or 1000 microg of CII were given 10 times orally. The development of arthritis, arthritis score, CII-specific delayed-type hypersensitivity (DTH) response, and CII-specific antibody levels were examined. RESULTS: Nasal administration of 10 microg of CII 15 times had the most prominent suppressive effects, reducing disease incidence by 50% and inhibiting both CII-specific IgG antibody and DTH responses. Of all the mice undergoing oral administration, those receiving 500 microg of CII 10 times showed the greatest suppressive potential. However, the treatment only delayed disease onset for roughly 3 weeks, lowering CII-specific IgG antibody levels but failing to suppress DTH responses. CONCLUSION: Nasal administration of CII reduced CIA development and inhibited CII-specific T cell and antibody responses to a greater degree than did oral administration.

Administration, Intranasal↗

PubMed2000

Cytoprotective effect of rabeprazole against ethanol-induced gastric mucosal damage: possible involvement of nitric oxide.

The cytoprotective effect of rabeprazole, a new proton pump inhibitor, against ethanol-induced gastric mucosal damage was investigated in rats. Rats received intraperitoneal injections of rabeprazole once only or once daily for 3 days. Subsequently, the rats were given 1 ml of absolute ethanol by oral intubation. Some rats given rabeprazole were treated with N-omega-nitro-L-arginine methyl ester (L-NAME) or indomethacin. Repeated administration of rabeprazole significantly inhibited ethanol-induced gastric mucosal damage, although single administration of this drug did not. Pretreatment with L-NAME abolished the cytoprotective effect of rabeprazole. This inhibitory effect of L-NAME was reversed by L-arginine but not by D-arginine. Pretreatment with indomethacin did not influence the cytoprotective effect of rabeprazole. These results suggest that repeated intraperitoneal administration of rabeprazole has a cytoprotective effect against ethanol-induced gastric mucosal damage and that this effect may be mediated via nitric oxide but not via prostaglandins.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2000

[Small cell carcinoma of the urinary bladder: a case report].

A 64-year-old man presented with asymptomatic gross hematuria. Cystoscopy revealed a non-papillary broad-based tumor on the posterior wall of the bladder. He had no evidence of metastases. Urine cytology showed a cluster of molded tumor cells with naked hyperchromatic nuclei, which indicated small cell carcinoma. He received preoperative irradiation to the bladder and underwent partial cystectomy. Pathological examination of the specimen showed small cell carcinoma at the stage of pT2. Two years after the operation, he had no evidence of recurrence.

Carcinoma, Small Cell↗

PubMed2000

[Study of the two-step tuberculin tests and gamma-interferon assays in elderly persons].

Recently, an outbreak of lung tuberculosis among elderly residents happened in the home for aged, and it has become a social problem. To analyze the problem of tuberculosis in the elderly persons, we performed two-step tuberculin tests at two weeks interval and gamma-interferon assays for diagnosis of human tuberculosis to residents in the home for aged. 45 males (age; 77.3 +/- 8.9 SD) and 118 females (age; 81.9 +/- 8.6 SD) elderly persons (> or = 60) were examined. Standard dose of PPD was injected intracutaneously, and read at 48 hours. Erythema of 10 mm diameter or more was considered positive. The results were as follows. (1) The percentages of positive reactors in the 1st (T1) and the 2nd (T2) tuberculin tests were 50.3% and 68.1%, respectively. (2) The diameters of erythema and percentage of positive reactors (T1) did not very with age, but the size of erythema increased from 13.5 mm (T1) to 21.2 mm (T2) among those below 80 years, and from 13.0 mm (T1) to 16.4 mm (T2) among those 80 years or higher (p < 0.01). (3) The percentage of positive reactors (T1) varied by sex, namely males react stronger than females. (4) A dose of interferon-gamma released specifically in response to PPD stimulation of whole blood cultures showed no close relation with the diameters of erythema. In conclusion, tuberculin reactivity waned among elderly persons, and the fact suggests that they would have lower resistance against new infections, and as a result, they might have higher risk of developing tuberculosis. Elderly residents should be performed two-step tuberculin tests at the time of their entrance to the home for aged, and negative reactors should carefully be followed up.

Aged↗

PubMed2000

Characterization of the anti-cancer-cell parasporal proteins of a Bacillus thuringiensis isolate.

An unusual activity, associated with non-insecticidal and non-haemolytic parasporal inclusion proteins of a Bacillus thuringiensis soil isolate, designated 89-T-26-17, was characterized. The parasporal inclusion of this isolate was bipyramidal, rounded at both ends, containing proteins of 180, 150, 120, 100, and 88 kDa. No homologies with the Cry and Cyt proteins of B. thuringiensis were detected based on N-terminal sequences. Proteolytic processing of the inclusion proteins by proteinase K, trypsin, and chymotrypsin produced a major protein of 64 kDa exhibiting cytocidal activity against human leukaemic T cells and uterus cervix cancer (HeLa) cells. The protease-activated proteins showed no cytotoxicity to normal T cells.

Amino Acid Sequence↗

PubMed2000

[A case of psoriatic arthropathy complicated with spinal fracture and epidural hematoma].

A 78-year-old man with psoriatic arthropathy complicated with traumatic spinal fracture and epidural hematoma is reported. He had fallen down the stairs. On admission one hour after injury, he developed an incomplete C6 quadriparesis. CT revealed a C6-7 fracture and dislocation on sagittal reconstruction. MR imaging disclosed the compression of the spinal cord between the posterior margin of the vertebral body and an epidural hematoma. The patient had had the skin lesion, psoriasis vulgaris, for about 20 years and been previously treated for uveitis. Serological tests for rheumatoid factor and HLA B-27 were negative. Emergent laminectomy and evacuation of the epidural hematoma were carried out because of progressive neurological deterioration. Osteoporotic laminar bone and ossified yellow ligament were observed to have been fractured. Conservative therapy was selected for spinal instability. Although a respiratory complication occurred postoperatively, he was transferred to the rehabilitation facility in an improved neurological condition.

Accidental Falls↗

PubMed2000

Structure of lamina propria lymphoid follicles and associated epithelium in the gastric mucosa during Helicobacter pylori infection in ulcer-bearing Mongolian gerbils.

To develop a gerbil model of Helicobacter pylori-induced chronic active gastritis comparable in severity to human lesions, we made acetic acid-induced ulcer in the anterior antral wall and concurrently challenged 1 x 10(8) colony-forming units bacteria per os. At 30 and 60 days after inoculation, the number of viable bacteria colonizing on the surface epithelium of the gastric mucosa was larger in ulcer-bearing animals compared to non-bearing ones. Furthermore, in the former animals, neutrophil and mononuclear cell infiltration as well as lymphoid follicle formation in the lamina propria was more prominent. Electron microscopically, lymphoid follicle-associated epithelium displayed specialized structures. Namely, brush cells interposed between mucous epithelial cells and characterized by prominent microfilament bundles and many apical vesicles or caveola specifically embraced the cluster of intraepithelially invading lymphocytes and macrophage-like cells by the attenuated cytoplasm in an analogous manner to M cells in Peyer's patches. The present study has demonstrated that ulcer formation enhances both H. pylori colonization and lamina propria lymphoid follicle formation and suggested that follicle-associated epithelium might play roles in the delivery of intraluminal antigen.

Animals↗

PubMed2000

[A case of intravascular malignant lymphomatosis presenting as cerebral infarction].

A case of intravascular malignant lymphomatosis (IML) presenting as progressive cerebral infarction is reported. A 62-year-old previously healthy male developed progressive dementia. MRI of the brain at the nearest hospital revealed multiple infarcts with unknown etiology. His level of consciousness deteriorated rapidly, and then he was transferred to our hospital for further evaluation. High grade fever, raised serum C reactive protein (CRP), and raised lymphoma markers (serum LDH and soluble IL-2 receptor (sIL-2R)) were observed. Repeated brain MRI disclosed progression of multifocal cerebral infarctions. We considered IML most likely, and we performed muscle biopsy. However muscle biopsy didn't demonstrate any proliferation of neoplastic cells of lymphoid origin within small vessels. Thereafter IML was diagnosed by brain biopsy. The patient underwent chemotherapy, but died of pneumonia due to severe myelosuppression. IML is a rare disease but most commonly shows neurological symptomatology as its clinical manifestation. Dementia is the most common neurological symptom, and progressive multiple infarction is the most common of the MRI findings. Rapidly progressive dementia associated with multiple infarction, when elevated CRP, LDH and sIL-2R are observed in the laboratory data, is suggestive of IML.

Biomarkers, Tumor↗

PubMed2000

The invasion of Mycobacterium tuberculosis into non-phagocytic cells.

To explore the ability of tubercle bacilli to invade and survive within non-phagocytic cells, we used in this study a human fibroblast cell line, WI-38, derived from normal embryonic lung and a human epithelial cell line, SQ-5, derived from lung squamous cell carcinoma. Live M. tuberculosis Erdman and M. tuberculosis H37Rv invaded WI-38 cells more efficiently than live M. tuberculosis H37Ra, M. bovis Ravenel, M. bovis BCG Tokyo and M. bovis BCG Pasteur. The capability of tubercle bacilli to invade WI-38 cells was Erdman > or = H37Rv > BCG Pasteur [symbol: see text] M. bovis Ravenel [symbol: see text] BCG Tokyo > H37Ra. A similar invasive ability was observed using SQ-5 cells. In contrast with live bacilli, heat-killed bacilli failed to invade WI-38 cells, whereas they were detected within SQ-5 cells. These results and incorporation of latex beads suggest that SQ-5 cells, but not WI-38 cells, possess phagocytic activity. H37Rv multiplied most actively within WI-38 cells when compared to H37Ra and BCG Tokyo, suggesting that the ability to invade and survive within non-phagocytic cells reflects the more active invasion of virulent M. tuberculosis than avirulent M. tuberculosis. The assay system used in this study may help us to clarify the virulence of tubercle bacilli in vitro.

Animals↗

PubMed1999

Potentially lethal damage repair and its inhibitory effect of caffeine in two yolk sac tumor cell lines with different radiosensitivities.

PURPOSE: In order to investigate the role of potentially lethal damage repair (PLDR) in cellular radiosensitivity, PLDR and its inhibitory effect by caffeine was examined. In addition, cell cycle distribution was also examined. MATERIALS AND METHODS: Two rat yolk sac tumor cell lines, NMT-1 and NMT-1R, with different radiosensitivities in vitro were used. The capacity for PLDR was examined using confluent-phase cells, and evaluated by calculating the recovery ratio. Inhibitory effect of caffeine on PLDR was examined with doses of 1, 5 and 10 mM. RESULTS: The capacity of PLDR in two cell lines reflected radiosensitivity. The recovery ratio after irradiation of 5 Gy was 2.8 in the radiosensitive NMT-1 and 5.2 in the radioresistant NMT-1R, and recovery reached its peak level at 6 h in both cell lines. The degree of inhibition of PLDR was weaker in NMT-1R than that in NMT-1 at the same dose level, and was correlated with reduction of G2-arrested cells by caffeine. CONCLUSIONS: The results of this study suggest that the capacity of PLDR may be one of the determinant factors for radiosensitivity in the two cell lines used, and the inhibitory effect of caffeine on PLDR was in part attributable to the modification of the cell cycle progression.

Animals↗

PubMed1999

Somatic mutation of the PTEN/MMAC1 gene in breast cancers with microsatellite instability.

The extent to which microsatellite instability (MI) contributes to the etiology of breast cancer has not been established in any large-scale studies. We examined 528 samples of tumor DNA from patients with primary breast cancer for MI, using 14 polymorphic CA-repeat markers. The frequency of MI in these tumors was unexpectedly low (10/528, 1.9%). The ten MI+ tumors were analyzed for mutations in five potential target genes that contain simple repeat sequences (TGFBIIR, IGF2R, hMSH6, BAX and PTEN/MMAC1). A somatic insertion of an extra adenine in the (A)6 region at codon 321-323 (exon 8) of the PTEN/MMAC1 gene, leading to a frame-shift, was identified in one tumor. This observation represented the first documented instance of PTEN/MMAC1 alteration in a MI+ primary breast cancer.

Breast Neoplasms↗

PubMed1999

DNA replication errors produced by the replicative apparatus of Escherichia coli.

It has been hard to detect forward mutations generated during DNA synthesis in vitro by replicative DNA polymerases, because of their extremely high fidelity and a high background level of pre-existing mutations in the single-stranded template DNA used. Using the oriC plasmid DNA replication in vitro system and the rpsL forward mutation assay, we examined the fidelity of DNA replication catalyzed by the replicative apparatus of Escherichia coli. Upon DNA synthesis by the fully reconstituted system, the frequency of rpsL-mutations in the product DNA was increased to 1.9x10(-4), 50-fold higher than the background level of the template DNA. Among the mutations generated in vitro, single-base frameshifts predominated and occurred with a pattern similar to those induced in mismatch-repair deficient E. coli cells, indicating that the major replication error was slippage at runs of the same nucleotide. Large deletions and other structural alterations of DNA appeared to be induced also during the action of the replicative apparatus.

Base Pairing↗

PubMed1999

Expression of the c-fos gene induced by parathyroid hormone in the bones of SAMP6 mice, a murine model for senile osteoporosis.

SAMP6 mice are a murine model for senile osteoporosis, characterized by low peak bone mass seen at 4 or 5 months of age. Parathyroid hormone (PTH)-induced c-fos expression was examined in the bones, bone-marrow cells and kidney tissues of 2-month-old male SAMP6 mice. SAMP2 mice, which have a higher peak bone mass, were used as controls. The expression of c-fos in the bone peaked at 30 min after 60 microg/kg of human PTH(1-34) administration. After peaking, the expression fell quickly in SAMP2 mice. This decrease in expression was delayed in SAMP6 mice and the expression was higher at 1 h than in SAMP2 mice. The phenomenon observed in the bone appears to be tissue specific as it was not seen in the bone-marrow cells or kidney tissue. Immunohistochemical studies showed that c-Fos protein was localized to the nuclei of some of the osteocytes and a few of the osteoblasts in the cortical bone, and that osteocytes expressing c-Fos protein increased after PTH treatment. These results suggest that osteocytes might contribute to the maintenance of higher levels of c-fos expression in the bones of SAMP6 mice and may be related to cortical osteopenia in these mice by modulating bone remodeling and/or modeling.

Animals↗

PubMed1999

Functional B-cell response in intrahepatic lymphoid follicles in chronic hepatitis C.

Intrahepatic lymphoid follicle (ILF) formation is one of the most characteristic and commonly observed histological features in patients with chronic hepatitis C. However, little is known regarding whether follicles in the liver belong to functional lymphoid tissues, where B cells are activated, differentiated, and proliferated, or if the lymphocytes are merely infiltrated after recruitment from the secondary lymphoid organs. To ascertain this possibility, we examined the expression of markers for B-cell activation, differentiation, and proliferation in ILFs in patients with chronic hepatitis C using surgically resected specimens, and compared them with specimens of perihepatic lymph nodes by an immunohistochemical technique. Germinal center (GC) formation in the ILFs was frequently found in HCV-positive cases. The distribution of immunoglobulin M (IgM)-, IgD-, and IgG-positive cells and the expression patterns of Ki-67, CD23, or bcl-2 and bcl-6 gene products in the follicles with GC formation in the liver of patients with chronic hepatitis C were similar to those of lymph nodes, indicating that B cells are activated, proliferated, and differentiated in the ILFs with GC formation in patients with chronic hepatitis C. Oligoclonal expansion of B cells in the livers with ILFs was confirmed by an analysis of immunoglobulin heavy chain (IgH) gene rearrangement determined by polymerase chain reaction (PCR). These data strongly suggest that ILFs with GC formation, which are frequently found in patients with chronic hepatitis C, may functionally be the same as those found in lymph nodes with respect to B-cell expansion and maturation.

Adult↗

PubMed1999

Identification of peak bone mass QTL in a spontaneously osteoporotic mouse strain.

The whole genome scan for quantitative trait loci (QTLs) specifying peak bone mass was performed with the F2 intercrosses of SAMP6, an established murine model of senile osteoporosis, exhibiting a significantly lower peak bone mass, and SAMP2, exhibiting a higher peak bone mass. Cortical thickness index (CTI), a parameter of bone mass of femurs, was measured in 488 F2 progeny at 4 months of age, when the animals attained peak bone mass by microphotodensitometry. Genetic markers were typed at 90 loci spanning all chromosomes except the Y. By interval mapping of 246 male F2 mice, two loci were identified with significant linkage to peak bone mass, one on Chromosome (Chr) 11 and another on Chr 13, with a maximum lod score of 10.8 (22.2% of the total variance) and 5.8 (10.0%), respectively. Another locus on the X Chr was suggestive of a QTL associated oppositely with a low peak bone mass to the SAMP2 allele. This association was consistent with the distribution of peak bone mass in the F1 and F2. These findings should be useful to elucidate the genetics of osteoporosis.

Animals↗

PubMed1999

Genetic typing of the senescence-accelerated mouse (SAM) strains with microsatellite markers.

The Senescence-Accelerated Mouse (SAM) strains constitute a murine model of accelerated senescence originating from the ancestral AKR/J strains and consist of nine senescence-prone (SAMP) strains and four senescence-resistant (SAMR) strains. The chromosomes (Chrs) of the SAM strains were typed with 581 microsatellite markers amplified by PCR, and the fundamental genetic information of the SAM strains was obtained. One-third of the examined markers displayed polymorphism among the strains, and only two alleles were detected in almost all loci among the SAM and AKR/J strains. However, in 12 loci (5.6% of total 215 polymorphic markers), the third allele was detected among the SAM strains. The genetic typing and developmental history suggested that the SAM strains were related inbred strains developed by the accidental crossing between the AKR/J strain and other unknown strain(s). Comparison of the distribution of the loci in the SAMP and the SAMR series revealed notable differences in the four regions on Chrs 4, 14, 16, and 17. This indicated that some of these chromosomal sites might contain the genes responsible for accelerated senescence in the SAMP series.

Aging↗