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Biomedical subjects

R Yamaguchi

Publications and source records attributed to R Yamaguchi.

At least 109 records · Page 6Linked to original sources
PubMed1996

Uptake and intracellular activity of NM394, a new quinolone, in human polymorphonuclear leukocytes.

The uptake of NM394, a new quinolone, by and its subsequent elution from human polymorphonuclear leukocytes were studied and compared with those of ofloxacin and ciprofloxacin. The kinetics of the uptake of NM394 was similar to that of ciprofloxacin. The maximum intracellular-to-extracellular concentration ratio was 12.3, compared with 8.6 for ciprofloxacin and 4.9 for ofloxacin at the extracellular concentration of 20 micrograms/ml. The elution of NM394 from human polymorphonuclear leukocytes occurs relatively slowly; 5 min after the removal of extracellular NM394, nearly 100% still remained in polymorphonuclear leukocytes, compared with ofloxacin, which was so rapidly eluted that only 12% remained. The uptake of NM394 was significantly decreased at 4 degrees C and by the presence of NaCN but was not affected by the presence of L-glycine, L-leucine, L-serine, adenosine, or NaF. NM394 showed intracellular activity at a concentration of 0.1 microgram/ml that significantly reduced the number of phagocytosed Pseudomonas aeruginosa cells with 2 h of incubation. These results suggest that uptake of NM394 by human polymorphonuclear leukocytes occurs via an active transport system differing from that of ofloxacin, whose uptake is affected by the presence of L-glycine and L-leucine, and that once accumulated, NM394 remains intracellularly active and participates in protection against bacterial infection.

Amino Acids↗
PubMed1996

Hemodynamic study of the anterior communicating artery.

BACKGROUND AND PURPOSE: The anterior communicating artery (ACoA) is a site of predilection for intracranial saccular aneurysms causing subarachnoid hemorrhage. ACoA aneurysms are frequently associated with an asymmetrical circle of Willis. In such cases, the ACoA is probably exposed to high hemodynamic stress caused by a considerable shunt flow across the ACoA to the distal segment of the contralateral anterior cerebral artery (ACA). In the present study, the flow pattern and flow-induced shear stress in the ACoA complex that may initiate aneurysmal lesions were studied under steady and pulsatile flow conditions. METHODS: Flow visualization was studied with dye injection and birefringent flow visualization in symmetrical and asymmetrical models of various sizes of ACoA. The distribution of wall shear stress was measured using an electrochemical method based on a diffusion-controlled reaction of ferricyanide ion to ferrocyanide ion at a platinum electrode embedded in the wall of the ACoA model. RESULTS: With equal flow rate (Reynolds number 150 to 600), vortical flow was formed in the mouth of the ACoA, and no cross flow through the ACoA was observed. The wall shear stress on the mid-wall of the ACoA was almost zero. However, as soon as the flow rate became unequal, a cross flow through the ACoA was observed. The stagnation point also appeared at the medial junction of the ACoA and ACA. The wall shear stress increased to a very high level at the wall of the ACoA and around the stagnation point. CONCLUSIONS: Geometric changes from the symmetrical to the asymmetrical ACoA develop higher shear stress on the ACoA than critical values and the stagnation point at the ACoA junction. A combination of these hemodynamic factors is considered to play an important role in initiation of aneurysm.

Blood Flow Velocity↗
PubMed1996

A retrospective study of canine senile plaques and cerebral amyloid angiopathy.

Epidemiologic and morphologic features of canine senile plaques (SPs) and cerebral amyloid angiopathy (CAA) were examined in 69 necropsied dogs. Dogs having only SPs (diffuse plaques) frequently suffered from malignant neoplasms, and their mean age was significantly lower than that of dogs with CAA only. Morphologically, diffuse plaques showed wide distribution compared with amyloid plaques or CAA and were predominantly concentrated in the frontal cortex. We were unable to find any significant relationship between the severity of the SPs and individual age. These findings may indicate that the occurrence of canine SPs is not strictly associated with aging only and that additional factors are related to the occurrence of SPs, especially diffuse plaques.

Age Factors↗
PubMed1996

Increase in the 8-hydroxyguanine repair activity in the rat kidney after the administration of a renal carcinogen, ferric nitrilotriacetate.

One type of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), is known to increase in rat kidney DNA after the administration of a renal carcinogen, ferric nitrilotriacetate (Fe-NTA). To determine the involvement of oxygen radicals in Fe-NTA carcinogenesis, we examined whether the 8-OH-Gua repair enzymes are induced in the rat kidney after Fe-NTA administration, in addition to our analysis of the 8-OH-Gua levels in the DNA, because the 8-OH-Gua repair activity is known to be induced in mammalian cells by oxidative stress due to ionizing radiation. The 8-OH-Gua repair enzyme activity was determined with an endonuclease assay using a 22-mer double strand DNA, which contains 8-OH-Gua at a specific position. A significant increase in the 8-OH-Gua repair activity was observed in the rat kidney after a single intraperitoneal injection of Fe-NTA (p < 0.01). This is the first report on the induction of the repair activity for 8-OH-Gua after treatment with a chemical carcinogen. This assay will be useful for evaluating the carcinogenicity of oxygen radical-forming chemicals.

Animals↗
PubMed1996

Inheritance of Chediak-Higashi syndrome in Japanese black cattle.

Fifty-six Japanese black cattle affected with Chediak-Higashi syndrome (C-HS) have been referred to Miyazaki University Veterinary Teaching Hospital during the past 12 years, and 44 pedigree records were collected. In pedigree analysis, the parents had no clinical sign, the affected dams had clinically normal calves, and approximately equal numbers of males and females were affected, we therefore considered this syndrome to be an autosomal recessive trait. Quantitative genetic analyses were then made in a restricted area. Segregation analysis by the a priori method in 8 families showed that C-HS was a simple autosomal recessive trait. Furthermore, 36 dams and their 257 offspring (including 8 C-HS affected cattle) were analyzed using population genetics in the same area. The result was the same as in the former analysis.

Animals↗
PubMed1996

[Administration and dosage of fluorouracil (5-FU) continuous i.v. infusion in patients with non-curative resected/non-resected gastric cancer].

This study was conducted to establish the optimum postoperative adjuvant chemotherapy with 5-FU in patients with gastric cancer. Seventy gastric cancer patients were treated after surgery with one of the following regimens; 5-FU 10 mg/kg/24 hrs c.i.v. x 24 days (arm A, n = 25); 5-FU 20 mg/kg/24 hrs c.i.v. x 4 days/w x 3 courses (arm B, n = 16); 5-FU 30 mg/kg/24 hrs c.i.v. x 2 days/w x 4 courses (arm C, n = 25). Blood 5-FU concentration, adverse effects and prognosis in each arm were compared. Changes in blood 5-FU concentrations were dose-related. The three-year survival rates in arms A, B and C were 15.0, 13.5 and 0.0%, respectively; they tended to be greater in arms A and B, but differences were not statistically significant. The most frequent adverse effects of the treatments were gastrointestinal, such as stomatitis. The incidence of reactions tended to be low in arm C, i.e., high-dose intermittent administration. Arm B (4 days-on, 3 days-off) was modified to 4 days-on, 6 days-off (arm B'), because severe stomatitis developed. The severity and incidence of stomatitis were reduced in the modified arm B group. We believe that intensive postoperative adjuvant chemotherapy for patients with gastric cancer should be designed using the arm B' approach.

Adult↗
PubMed1996

Fibromuscular dysplasia of the visceral arteries.

Fibromuscular dysplasia (FMD) commonly involves the renal and carotid arteries. However, visceral arterial involvement is rare. We report a 39-yr-old male who developed ischemic bowel disease twice (once in the jejunal artery and once in the sigmoid artery) as a result of FMD. First ischemic change occurred in the sigmoid colon with manifestation of melena and abdominal pain, and the second occurred in the jejunum, with severe abdominal pain and intestinal stenosis. Angiography revealed the "string of beads" appearance, characteristic of FMD, in those two arteries responsible for the ischemic lesions. Fasting therapy with intravenous hyperalimentation improved both lesions, but secondary stenosis caused by ischemia occurred in the jejunum. Surgical resection of the stenotic jejunum was required. Although the abnormal arteries that had been imaged as a "string of beads" on angiography were not resected, the postoperative course has been uneventful and satisfactory.

Abdominal Pain↗
PubMed1996

Therapeutic effect of the quinolone prodrug prulifloxacin against experimental urinary tract infections in mice.

The in vitro antibacterial activity of prulifloxacin (CAS 123447-62-1, NM441), a new quinoline prodrug, against clinical isolates from urinary tract infections was investigated. In addition, it was compared with ofloxacin (CAS 82419-36-1), levofloxacin (CAS 100986-85-4), ciprofloxacin urinary tract infections in mice, as well as its pharmacokinetics. 1. The antibacterial activity of NM394 (6-fluoro-1-methyl-4-oxo-7-(1-piperazinyl)-4H-[1,3]thiazeto[3,2- a]quinoline-3-carboxylic acid), an active metabolite of prulifloxacin, against gram-positive clinical isolates was inferior to that of levofloxacin and tosufloxacin, and equal to that of ofloxacin and ciprofloxacin. Against gram-negative clinical isolates, the activity of NM394 was superior to that of the reference drugs. 2. The therapeutic effect of prulifloxacin on experimental urinary tract infection with Escherichia coli in mice was equal to that of tosufloxacin and ciprofloxacin and superior to that of ofloxacin and levofloxacin. Its therapeutic effect on Pseudomonas aeruginosa infection was equal to that of tosufloxacin and ciprofloxacin, and superior to that of ofloxacin. Against urinary tract infection with olfloxacin-resistant Enterobacter cloacae, prulifloxacin was the most effective of all the drugs tested. 3. The maximal serum concentration of prulifloxacin was slightly higher than that of ciprofloxacin, and the area under the curve (AUC) for prulifloxacin was 1/4 that of ofloxacin, levofloxacin and tosufloxacin. The maximal concentration and AUC of prulifloxacin in lung and kidney were slightly higher than the corresponding values for ciprofloxacin but only 1/2 to 1/4 of the values for ofloxacin, levofloxacin and tosufloxacin. In conclusion, prulifloxacin (NM394) showed potent antibacterial activity against clinical isolates and potent therapeutic efficacy against experimental infection in spite of its lower AUCs compared with the reference drugs. These findings suggest that prulifloxacin may be a useful drug in the treatment of urinary tract infections.

Animals↗
PubMed1996

[A case of internal supravesical hernia].

We report a case of internal supravesical hernia. A 74-year-old male with complaint of abdominal pain underwent an operation for small intestinal obstruction due to its incarceration into the internal supravesical hernia. Retrospectively, the preoperative abdominal CT film showed the relation of the incarcerated intestine, the urinary bladder, and the middle umbilical ligament. This is the first case of the internal supravesical hernia in which the preoperative CT had taken and it will contribute to the preoperative correct diagnosis in the future.

Aged↗
PubMed1995

Delayed-type hypersensitivity to a recombinant mycobacterial antigen, MPB64, in guinea pigs sensitized to Mycobacterium tuberculosis or Mycobacterium bovis BCG.

Recombinant MPB64 (rMPB64), a mycobacterial antigen, was obtained from an Escherichia coli clone transformed with a recombinant expression vector, pMAL64c. The rMPB64 was examined for the activity to elicit delayed-type hypersensitivity (DTH) in guinea pigs injected with liver Mycobacterium tuberculosis H37Rv or live M. bovis BCG Tokyo. It was found that rMPB64 has the same reactivity as native MPB64 (nMPB64) or MPT64 (nMPT64) and the potency to elicit DTH was 13.4 times higher than that of PPD. Because MPB64 is secreted only by living M. tuberculosis and some strains of BCG, it is possible to use this antigen for the diagnosis of tuberculosis.

Amino Acid Sequence↗
PubMed1995

Sequence of the canine c-yes proto-oncogene.

Cloning of the canine yes oncogene was attempted from a cDNA library derived from a healthy canine spleen using a human c-yes-1 probe. The nucleotide and amino acid sequences revealed that the canine yes gene contained an open reading frame consisting of 539 amino acids. Its product had a molecular mass of 60,368 Daltons and showed 95.9 per cent and 90.4 per cent homology with human and chick p61c-yes, respectively. Moreover, the product had a myristylation signal, src homology region (SH) 3, SH2, and tyrosine kinase domains showing 98.8 per cent and 96.0 per cent homology with those of human beings and chickens, respectively. These findings indicate that the products of the canine yes gene may have non-receptor-type tyrosine kinase activity on the cell membrane, as is the case in human and chick p61c-yes.

Amino Acid Sequence↗
PubMed1995

In vitro growth inhibition activities of recombinant feline interferon on all lines derived from canine tumours.

To evaluate the anti-tumour effect of recombinant feline interferon (rFeIFN) against canine neoplastic cells, the antiproliferation and anti-colony-forming activities of rFeIFN were investigated in vitro, using four cell lines derived from canine tumours; oral acanthomatous epulis (MCA-B1), mammary benign mixed tumour (MCM-B2), squamous cell carcinoma (CSCC), and malignant melanoma (CMC-1). The rFeIFN had a dose-dependent inhibitory effect on the cell growth and colony formation of all the cell lines, although the degree of inhibition was lower than that in the feline cell lines used as a positive control, and the sensitivity of the cells to rFeIFN differed.

Animals↗
PubMed1995

A cell line (MCA-B1) derived from a canine oral acanthomatous epulis.

A canine oral acanthomatous epulis cell line designated MCA-B1 was established in culture. Immunohistochemically the cells reacted intensely with anti-keratin antibody and mildly with anti-vimentin antibody. An ultrastructural examination of the cells confirmed their epithelial nature. The modal chromosome number was 72 and the cloning efficiency in soft agar culture ranged from 3.4 to 16.1 per cent with a population doubling time of nine hours. MCA-B1 has since been passaged more than 70 times and maintained in culture for more than a year. Most of the characteristics of the original canine tumour cells were retained in the isolated cell line.

Animals↗
PubMed1995

Establishment of a cell line (MCM-B2) from a benign mixed tumour of canine mammary gland.

A cell line was established from a benign mixed tumour of the canine mammary gland. Light microscopy of the cells cultured on plastic dishes revealed monolayer colonies. Cells that grew within the collagen gel matrix formed large three-dimensional colonies with a branching pattern. Immunohistochemically, these cells reacted intensely with anti-vimentin antiserum and mildly with anti-desmin antiserum. Ultrastructural examination revealed a large nucleus, intracytoplasmic organelles and intermediate filaments, which varied among cells. The cells possessed an abnormal chromosome number, an average of 80 per cell. Histologically, the xenografted tumour of cultured cells was similar to anaplastic carcinoma and reacted strongly with anti-vimentin antiserum, mildly with anti-desmin antiserum, and weakly with anti-keratin antiserum. The average chromosome number of cells form the xenografted tumour was the same as that of the original cultured cells. These findings suggest that the cell line might be derived from stem cells or atypical cells, and that it should be useful as model for the study of cell differentiation and proliferation in canine mammary tumours.

Aneuploidy↗
PubMed1995

Transplantation of a cell line derived from a canine benign mixed mammary tumour into nude mice.

The MCM-B2 canine mammary cell line was serially transplanted into nude mice. The tumour masses consisted of elongated pleomorphic cells of varying size in the first to third passages; oval cells, becoming rounder, in the sixth to eighth passages; and cord-like, glandular and duct-like structures with compact radiating projections in the ninth and tenth passages. Ultrastructural and immunohistochemical examination of round cells confirmed their epithelial cell nature, but the morphology of the elongated and oval cells was identical with that of the original cell line. The findings suggest that the MCM-B2 cell line is a multipotential stem cell or is derived from glandular differentiation of mammary gland.

Animals↗
PubMed1995

Laparoscopic evaluation of indeterminate renal cysts.

OBJECTIVES: To determine the efficacy and safety of laparoscopic evaluation of indeterminate renal cysts. METHODS: Ten patients with indeterminate renal cysts (5 Bosniak type II and 5 Bosniak type III) underwent transperitoneal laparoscopic aspiration of cyst fluid for cytologic analysis with examination, biopsy, and excision of the cyst wall and base. RESULTS: All procedures were successful and without complications. All the lesions were benign. CONCLUSIONS: Laparoscopic evaluation of indeterminate renal cysts is safe and effective. The procedure alleviates patient anxiety about the nature of the lesion and obviates years of radiologic surveillance, thus reducing costs.

Adult↗
PubMed1995

Quality of portal verification images using GLP7 film.

RATIONALE AND OBJECTIVES: To improve portal verification radiographs, we tested the application of GLP7 film. METHODS: The quality of the portal verification radiograph using the XV cassette-GLP7 film combination and the XL cassette-GLP7 film combination was investigated. The XV cassette-XV2 film combination and the SA cassette-GS screen-XTL film combination also were used for comparison. RESULTS: The characteristic curves showed that the relative speeds were 0.32 and 0.47 for the XV-GLP7 and XL-GLP7 combinations and that the average gradients were 1.93, 2.14, and 1.32 for the XV-GLP7, XL-GLP7, and XV-XV2 combinations, respectively. In the experiment using Burger's phantom, the smallest visible volumes were 11.8, 11.3, 28.7, and 19.6 mm3 for the XV-GLP7, XL-GLP7, XV-XV2, and SA-GS-XTL combinations, respectively. In the lower dosage treatment in the clinic, there were no marked differences between the GLP7 film and XV2 film. However, in the higher dosage treatment, the GLP7 film had a better quality than did the XV2 film. CONCLUSION: Portal verification radiographs using GLP7 film are of sufficient quality for clinical use.

Humans↗